WO2012043729A1 - Secondary-battery porous-membrane slurry, secondary-battery porous membrane, secondary-battery electrode, secondary-battery separator, secondary battery, and method for manufacturing secondary-battery porous membrane - Google Patents

Secondary-battery porous-membrane slurry, secondary-battery porous membrane, secondary-battery electrode, secondary-battery separator, secondary battery, and method for manufacturing secondary-battery porous membrane Download PDF

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Publication number
WO2012043729A1
WO2012043729A1 PCT/JP2011/072403 JP2011072403W WO2012043729A1 WO 2012043729 A1 WO2012043729 A1 WO 2012043729A1 JP 2011072403 W JP2011072403 W JP 2011072403W WO 2012043729 A1 WO2012043729 A1 WO 2012043729A1
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Prior art keywords
acrylic polymer
secondary battery
polymer particles
porous membrane
particles
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PCT/JP2011/072403
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French (fr)
Japanese (ja)
Inventor
金田　拓也
琢也 石井
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日本ゼオン株式会社
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Priority to CN201180057676.9A priority Critical patent/CN103262297B/en
Priority to KR1020137010881A priority patent/KR101921659B1/en
Priority to JP2012536550A priority patent/JP5605591B2/en
Publication of WO2012043729A1 publication Critical patent/WO2012043729A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/42—Acrylic resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a secondary battery porous membrane slurry, and more specifically, a secondary battery porous membrane formed on the surface of an electrode or separator of a lithium ion secondary battery, which has high reliability and can contribute to improvement of battery cycle characteristics.
  • the present invention relates to a secondary battery porous membrane slurry for manufacturing.
  • the present invention also relates to a secondary battery electrode, a secondary battery separator and a secondary battery provided with such a secondary battery porous membrane.
  • lithium ion secondary batteries exhibit the highest energy density, and are often used especially for small electronics. In addition to small-sized applications, development for automobiles is also expected. Among them, there is a demand for extending the life of lithium ion secondary batteries and further improving safety.
  • a lithium-ion secondary battery uses a polyolefin-based organic separator such as polyethylene or polypropylene in order to prevent a short circuit between the positive electrode and the negative electrode.
  • a polyolefin-based organic separator such as polyethylene or polypropylene
  • the polyolefin-based organic separator has a physical property of melting at 200 ° C. or lower, when the battery becomes hot due to internal or external stimulation, the organic separator shrinks or melts, and the volume of the organic separator is increased. Change. As a result, an explosion or the like may occur due to a short circuit between the positive electrode and the negative electrode, discharge of electric energy, or the like.
  • a layer (porous film) containing non-conductive particles such as inorganic particles on the polyolefin-based organic separator or on the electrode (positive electrode or negative electrode) ) Is proposed. Furthermore, in order to prevent thermal runaway due to an abnormal reaction of the battery, a porous film including polymer particles that are melted by heat and polymer particles that increase the degree of swelling into an electrolyte solution by heat has been proposed. When the temperature of the secondary battery rises abnormally due to a short circuit or the like, fine pores in the porous film are blocked by melting or swelling of the polymer particles, thereby preventing ions from passing between the electrodes. It is considered to have a function (shutdown function) that cuts off current and suppresses further temperature rise.
  • Patent Document 1 describes a porous film containing heat-resistant resin fine particles and organic fine particles having a shutdown function for improving safety. Further, it is described that an ethylene-vinyl acetate polymer is used as a binder for a porous film.
  • Patent Document 2 describes a method for improving powder-off of inorganic filler from a porous film by using water-dispersible acrylic polymer particles having a hydrophilic group such as sulfonic acid as a binder. Further, it is described that a water-dispersible acrylic polymer particle can have a tough and flexible porous film by further having a crosslinkable group.
  • JP 2006-139978 A International Patent Publication WO2009 / 123168
  • the porous film described in Patent Document 1 uses an ethylene-vinyl acetate polymer as a binder, the heat-resistant resin fine particles in the slurry for forming the porous film And the dispersibility of the organic fine particles is not sufficient, and the uniformity of the porous film is poor. As a result, the porous membrane may not have sufficient strength and a shutdown function.
  • the porous film described in Patent Document 2 is excellent in dispersibility of the inorganic filler in the porous film slurry.
  • the present invention can be produced using a secondary battery porous membrane slurry excellent in coatability and dispersibility of non-conductive particles, and can improve the cycle characteristics of the obtained secondary battery. It aims at providing a secondary battery porous membrane with high intensity. Moreover, it aims at providing the secondary battery electrode and secondary battery separator with a favorable shutdown function.
  • the uniformity and strength of the porous film can be improved by introducing a sulfonic acid group and an epoxy group into different acrylic polymer particles and using them as a binder. It was found that it can be improved. That is, by using a specific binder, the crosslinking reaction in the slurry production process can be suppressed, and the viscosity of the slurry can be reduced. Therefore, the dispersibility of non-conductive particles in the porous membrane slurry and the coating property of the porous membrane slurry can be improved, and a porous membrane having high uniformity and strength can be obtained.
  • the present inventor has improved the dispersibility of non-conductive particles in the porous membrane slurry and the coating property of the porous membrane slurry, so that in addition to the productivity of the porous membrane, the secondary using the porous membrane It has been found that the cycle characteristics of the battery are also improved.
  • the gist of the present invention aimed at solving such problems is as follows. (1) comprising non-conductive particles containing an organic polymer, a binder and a solvent; The secondary battery porous membrane slurry in which the binder contains acrylic polymer particles A having sulfonic acid groups and acrylic polymer particles B having epoxy groups.
  • the acrylic polymer particles A and the acrylic polymer particles B are The secondary battery porous membrane slurry according to (1) or (2), comprising a (meth) acrylonitrile monomer unit and a (meth) acrylate monomer unit.
  • the content ratio of the (meth) acrylonitrile monomer unit in the polymer particles is 2.5 to 40% by mass
  • the secondary battery porous membrane slurry according to (3), wherein the content ratio of the (meth) acrylic acid ester monomer unit in the polymer particles is 60 to 97.5% by mass.
  • the content ratio of sulfonic acid groups in the acrylic polymer particles A is 0.04 to 5.8 mass%, and the content ratio of epoxy groups in the acrylic polymer particles B is 0.03 to 3.0 mass%.
  • the weight ratio of the sulfonic acid group in the acrylic polymer particle A to the epoxy group in the acrylic polymer particle B is 0.2 to 3.
  • the temperature at which the weight loss ratio of the non-conductive particles reaches 10% by mass when heated at a heating rate of 10 ° C./min in a nitrogen atmosphere by a thermobalance is 250 ° C. or more,
  • the non-conductive particles have an average particle size of 0.1 to 2.0 ⁇ m;
  • a secondary battery porous membrane formed by forming the secondary battery porous membrane slurry according to any one of (1) to (8) above into a film and drying it.
  • Organic separator A secondary battery separator comprising the secondary battery porous film according to (9), which is laminated on the organic separator.
  • a secondary battery including a positive electrode, a negative electrode, an organic separator, and an electrolyte solution, wherein the secondary battery porous film according to (9) is laminated on any of the positive electrode, the negative electrode, and the organic separator.
  • a method for producing a secondary battery porous membrane comprising a step of applying the secondary battery porous membrane slurry according to any one of (1) to (8) above to a substrate and then drying.
  • a secondary battery for producing a secondary battery porous film that is excellent in uniformity and strength and can contribute to cycle characteristics of a secondary battery by including non-conductive particles and a binder having a characteristic composition.
  • a porous membrane slurry is provided.
  • the porous film slurry is excellent in dispersibility and coatability.
  • the secondary battery porous membrane produced using the porous membrane slurry is laminated on the surface of the electrode or organic separator, thereby preventing non-conductive particles and electrode active material from detaching (powder-off). Excellent shutdown function (reliability).
  • the secondary battery porous membrane slurry of the present invention (hereinafter sometimes referred to as “porous membrane slurry”) is a slurry for forming a secondary battery porous membrane described later.
  • the porous film slurry contains non-conductive particles and a binder having a characteristic composition, and the non-conductive particles, the binder and optional components are uniformly dispersed in a solvent described later as a solid content.
  • Non-conductive particles The nonconductive particles used in the present invention include an organic polymer.
  • metal contamination hereinafter sometimes referred to as “metal foreign matter”
  • the production cost of the secondary battery porous membrane slurry can be reduced.
  • the non-conductive particles preferably contain divinylbenzene monomer units.
  • the content ratio of the divinylbenzene monomer unit in the total monomer weight in the non-conductive particles is preferably 20 to 80% by mass, more preferably 25 to 70% by mass, and particularly preferably 30 to 60% by mass. .
  • the crosslink density of the nonconductive particles is increased, so that the heat resistance of the nonconductive particles is improved, and the reliability of the obtained secondary battery porous film is also improved. improves.
  • the non-conductive particles preferably further contain an ethyl vinyl benzene monomer unit.
  • the content ratio of the ethyl vinylbenzene monomer unit in the total monomer weight in the non-conductive particles is preferably 3.2 to 48% by mass, more preferably 10 to 40% by mass.
  • the content ratio (divinylbenzene / ethylvinylbenzene) of the divinylbenzene monomer unit and the ethylvinylbenzene monomer unit contained in the nonconductive particles is preferably 1.0 to 5.25, more preferably 1. It is 25 to 5.00, particularly preferably 1.25 to 4.75.
  • the crosslink density of the nonconductive particles is increased, so that the heat resistance of the nonconductive particles is increased. Improves.
  • the flexibility and strength of the obtained secondary battery porous membrane are improved.
  • the electrode active material can be prevented from being detached (powder falling), and therefore a secondary battery using the secondary battery porous film exhibits excellent cycle characteristics.
  • the non-conductive particles preferably contain a polar group-containing monomer in addition to the two types of monomer units.
  • the polar group-containing monomer is a monomer that contains a polar group in the molecular structure and can be copolymerized with divinylbenzene and ethylvinylbenzene.
  • a polar group refers to a functional group that can dissociate in water or a functional group having polarization. Specifically, a carboxyl group, a sulfonic acid group, a hydroxyl group, an amide group, a cationic group, a cyano group, an epoxy group, and the like. Is mentioned.
  • Examples of the carboxyl group-containing monomer include monocarboxylic acids, dicarboxylic acids, dicarboxylic acid anhydrides, and derivatives thereof.
  • Monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxyacrylic acid , ⁇ -diaminoacrylic acid and the like.
  • dicarboxylic acid examples include maleic acid, fumaric acid, itaconic acid, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, and fluoromaleic acid.
  • dicarboxylic acid anhydride examples include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride.
  • Dicarboxylic acid derivatives include maleic esters such as methyl allyl maleate, diphenyl maleate, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, and fluoroalkyl maleate.
  • sulfonic acid group-containing monomer examples include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylic acid-2-ethyl sulfonate, 2-acrylamido-2-methylpropane sulfonic acid. And 3-allyloxy-2-hydroxypropanesulfonic acid.
  • hydroxyl group-containing monomer examples include ethylenically unsaturated alcohols such as (meth) allyl alcohol, 3-buten-1-ol, 5-hexen-1-ol; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate Ethylenically unsaturated carboxylic acids such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, di-2-hydroxyethyl maleate, di-4-hydroxybutyl maleate and di-2-hydroxypropyl itaconate Alkanol esters of acids; general formula CH 2 ⁇ CR 1 —COO— (C n H 2n O) m —H (m is an integer from 2 to 9, n is an integer from 2 to 4, R 1 is a hydrogen or methyl group 2-hydroxy ester of polyalkylene glycol and (meth) acrylic acid represented by Mono (meth) acrylic esters of dihydroxy esters of dicarboxylic acids such as til-2 ′-(meth)
  • amide group-containing monomer examples include acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide and the like.
  • Examples of the cationic group-containing monomer include dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate.
  • Examples of the cyano group-containing monomer include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile.
  • Examples of the epoxy group-containing monomer include glycidyl acrylate and glycidyl methacrylate.
  • salts of carboxyl group-containing monomers sulfonic acid group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, cationic group-containing monomers, and cyano group-containing monomers
  • the monomers listed above and appropriate combinations thereof can be used.
  • Composed of various ions alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt, organic amine salts such as ammonium salt, monoethanolamine salt and triethanolamine saltcan be mentioned.
  • polar group-containing monomer a carboxyl group-containing monomer and an amide group-containing monomer are preferable, and acrylic acid, methacrylic acid, itaconic acid, and acrylamide are particularly preferable.
  • the content ratio of the polar group-containing monomer in the total monomer weight in the non-conductive particles is preferably 0.05 to 4% by mass, more preferably 0.1 to 3% by mass, and particularly preferably 0.2 to 2%. % By mass.
  • the content ratio of the polar group-containing monomer in the total monomer weight in the non-conductive particles is in the above range, excellent dispersibility and low moisture content on the surface of the non-conductive particles have excellent cycle characteristics. Show.
  • the non-conductive particles may contain an arbitrary monomer unit in addition to the above three types of monomer units.
  • the optional monomer include polyvalent (meth) acrylate compounds, aromatic monovinyl compounds, (meth) acrylic acid ester monomers, conjugated diene monomers, vinyl ester compounds, and ⁇ -olefin compounds. Two or more of these monomers may be contained in the nonconductive particles.
  • polyvalent (meth) acrylate compound examples include polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol diacrylate, neopentyl glycol diacrylate, polypropylene glycol diacrylate, and 2,2′-bis.
  • Diacrylate compounds such as (4-acryloxypropyroxyphenyl) propane and 2,2′-bis (4-acryloxydiethoxyphenyl) propane; trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate
  • Triacrylate compounds such as; tetraacrylate compounds such as tetramethylol methane tetraacrylate; ethylene glycol dimethacrylate, diethylene glycol Dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol Dimethacrylate compounds such as dimethacrylate, polypropylene glycol dimethacrylate, and 2,2′-bis (4-methacryloxydiethoxyphenyl
  • aromatic monovinyl compound examples include styrene, ⁇ -methylstyrene, fluorostyrene, vinyl pyridine and the like.
  • acrylate monomer examples include butyl acrylate, 2-ethylhexyl ethyl acrylate, N, N′-dimethylaminoethyl acrylate, and the like.
  • methacrylic acid ester monomer examples include butyl methacrylate, 2-ethylhexyl methacrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, N, N′-dimethylaminoethyl methacrylate and the like.
  • conjugated diene monomer examples include butadiene and isoprene.
  • vinyl ester compounds examples include vinyl acetate.
  • Examples of ⁇ -olefin compounds include 4-methyl-1-pentene.
  • any one of the above monomers can be used alone or in combination of two or more.
  • styrene, methyl methacrylate, or a combination thereof is particularly preferable from the viewpoint of reactivity with divinylbenzene and ethylvinylbenzene.
  • the content ratio of arbitrary monomer units in the total monomer weight in the non-conductive particles is preferably 3 to 80% by mass, more preferably 4 to 70% by mass, and particularly preferably 5 to 60% by mass. .
  • the preferable content ratio is 4.5 to 76.5% by mass based on the total amount of monomers constituting the non-conductive particles. is there. In the case where both styrene and methyl methacrylate are contained, it is preferable that the sum thereof is within this range.
  • the heat resistance of the non-conductive particles can be improved, the heat resistance of the porous film can be improved, and thus at a high temperature.
  • production of the short circuit of a battery can be reduced.
  • the content ratio of styrene and / or methyl methacrylate to 4.5% by mass or more, it is possible to prevent the dispersibility of the nonconductive particles from being lowered, to increase the strength of the porous film, and to achieve film uniformity. Can also be obtained.
  • the production method of the non-conductive particles is not particularly limited, and the emulsion polymerization method or the soap-free polymerization method is performed by dissolving or dispersing the monomer constituting the non-conductive particles and other optional components as necessary in a dispersion medium. To polymerize in such a dispersion.
  • emulsion polymerization it is preferable to carry out the polymerization in a plurality of stages in order to obtain a desired particle diameter and average circularity.
  • a seed polymer particle is formed by first polymerizing a part of the monomer constituting the non-conductive particle, and then the other polymer is absorbed in the seed polymer particle and polymerized in that state.
  • non-conductive particles seed polymerization method.
  • the polymerization can be further divided into a plurality of stages.
  • the seed polymer particle A is formed by using a part of the monomer constituting the nonconductive particle, and the seed polymer particle A and another single amount constituting the nonconductive particle.
  • a seed polymer particle B having a larger particle size using the body, and further, the seed polymer particle B, the remaining monomers constituting the non-conductive particles, and other optional components as necessary Can be used to form non-conductive particles having a larger particle size.
  • the seed polymer particles A and the seed polymer particles B using a part or all (preferably all) of the polar group-containing monomers of the monomers constituting the non-conductive particles when forming the seed polymer particles A and the seed polymer particles B, This is preferable for ensuring the stability of the particles. Furthermore, in this case, it is possible to use styrene, which is an arbitrary monomer, as the monomer for forming the seed polymer particles A. When forming the seed polymer particles B and the non-conductive particles, the seed polymer particles It is preferable in order to ensure the absorbability of the monomer.
  • the monomer constituting the nonconductive particles is not in a state where all the monomers are mixed in the polymerization. Also good.
  • the composition of the monomer derived from the polymerization unit constituting the nonconductive particles in the finally obtained nonconductive particles constitutes the nonconductive particles described above. It is preferable that the composition ratio of the monomers to be satisfied is satisfied.
  • Examples of the medium used for the polymerization of the monomers constituting the nonconductive particles include water, organic solvents, and mixtures thereof.
  • the organic solvent those which are inert to radical polymerization and do not inhibit the polymerization of monomers can be used.
  • Specific examples of the organic solvent include alcohols such as methanol, ethanol, propanol, cyclohexanol and octanol, esters such as dibutyl phthalate and dioctyl phthalate, ketones such as cyclohexanone, and mixtures thereof.
  • an aqueous medium such as water is used as a dispersion medium, and emulsion polymerization can be performed as polymerization.
  • the amount ratio of these when the seed polymer particles and the monomer are reacted is preferably 2 to 19 parts by weight, more preferably 3 to 16 parts by weight, based on 1 part by weight of the seed polymer particles. Even more preferably, it is 4 to 12 parts by mass.
  • the usage-amount of a monomer 2 mass parts or more with respect to 1 mass part of seed polymer particles the mechanical strength and heat resistance of the nonelectroconductive particle obtained can be improved.
  • the monomer can be efficiently absorbed into the seed polymer particle by setting the amount of the monomer used to 19 parts by mass or less with respect to 1 part by mass of the seed polymer particle, a single amount that is not absorbed by the seed polymer particle.
  • the body weight can be kept in a small range.
  • the particle size of the non-conductive particles can be controlled well, the generation of coarse particles having a wide particle size distribution and a large amount of fine particles can be prevented.
  • Specific operations for the polymerization include a method in which the monomer is added to the aqueous dispersion of seed polymer particles at a time, and a method in which the monomer is divided or continuously added while performing the polymerization. It is preferred that the monomer be absorbed by the seed polymer particles before polymerization begins and substantial crosslinking occurs in the seed polymer particles. If the monomer is added after the middle of the polymerization, the monomer is not absorbed by the seed polymer particles, so that a large amount of fine particles are generated, the polymerization stability is deteriorated, and the polymerization reaction may not be maintained.
  • the seed polymer particles it is preferable to add all monomers to the seed polymer particles before the start of polymerization, or to finish adding all monomers before the polymerization conversion rate reaches about 30%.
  • An optional component can be added to the polymerization reaction system in addition to the monomer constituting the non-conductive particles and the dispersion medium.
  • components such as a polymerization initiator, a surfactant, and a suspension protective agent can be added.
  • a polymerization initiator a general water-soluble radical polymerization initiator or oil-soluble radical polymerization initiator can be used, but a monomer that is not absorbed by the seed polymer particles rarely initiates polymerization in the aqueous phase. In view of this, it is preferable to use a water-soluble radical polymerization initiator.
  • water-soluble radical polymerization initiator examples include potassium persulfate, sodium persulfate, cumene hydroperoxide, hydrogen peroxide, or the water-soluble initiator or an oil-soluble initiator described later and a reducing agent such as sodium bisulfite.
  • a reducing agent such as sodium bisulfite.
  • Oil-soluble radical polymerization initiators include benzoyl peroxide, ⁇ , ⁇ '-azobisisobutyronitrile, t-butylperoxy-2-ethylhexanoate, 3,5,5-trimethylhexanoyl A peroxide etc. can be mentioned.
  • oil-soluble radical polymerization initiators t-butylperoxy-2-ethylhexanoate can be preferably used.
  • a water-soluble polymerization inhibitor such as potassium dichromate, ferric chloride, or hydroquinone because generation of fine particles can be suppressed.
  • a surfactant a normal one can be used, and examples thereof include anionic emulsifiers such as sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium dialkylsulfosuccinate, and a formalin condensate of naphthalenesulfonic acid.
  • nonionic surfactants such as polyoxyethylene nonylphenyl ether, polyethylene glycol monostearate, sorbitan monostearate can be used in combination.
  • Preferred examples of the suspension protective agent include polyvinyl alcohol, carboxymethyl cellulose, sodium polyacrylate, and a fine powder inorganic compound.
  • the shape of the non-conductive particles used in the present invention is not particularly limited, such as a spherical shape, a needle shape, a rod shape, a spindle shape, and a plate shape, but a spherical shape, a needle shape, and a spindle shape are preferable.
  • porous particles can also be used as the non-conductive particles.
  • the content ratio of the non-conductive particles per 100% by mass of the total solid content of the porous membrane slurry is preferably 70 to 97% by mass, more preferably 80 to 95% by mass, and particularly preferably 85 to 95% by mass.
  • the content ratio of the nonconductive particles per 100% by mass of the total solid content of the porous membrane slurry within the above range, a porous membrane exhibiting high thermal stability can be obtained.
  • desorption (powder removal) of non-conductive particles from the porous film can be suppressed, and a porous film having high strength can be obtained, and deterioration of battery characteristics such as cycle characteristics can be prevented.
  • the non-conductive particles have high heat resistance from the viewpoint of imparting heat resistance to the porous film and improving the reliability of a secondary battery electrode and a secondary battery separator described later.
  • the temperature at which the weight loss rate of the non-conductive particles reaches 10% by mass when heated at a heating rate of 10 ° C./min in a thermobalance analysis in a nitrogen atmosphere is preferably 250 ° C. or more, more preferably It is 300 ° C. or higher, particularly preferably 360 ° C. or higher.
  • the upper limit of the temperature is not particularly limited, but can be, for example, 450 ° C. or less.
  • non-conductive particles having a metal foreign matter content of 100 ppm or less.
  • the metal foreign matter or metal ions are eluted in the porous membrane slurry, and this causes ionic crosslinking with the polymer in the porous membrane slurry. Aggregation results in a decrease in the porosity of the porous membrane. Therefore, there is a possibility that the rate characteristic (output characteristic) of the secondary battery using the porous film is deteriorated.
  • the inclusion of Ca, Co, Cu, Fe, Mg, Ni, Zn, Cr and the like is most undesirable.
  • the metal content in the non-conductive particles is preferably 100 ppm or less, more preferably 50 ppm or less, in terms of the total amount of these metal ions.
  • metal foreign matter means a simple metal or a metal ion other than non-conductive particles.
  • the content of the metal foreign matter in the non-conductive particles can be measured using ICP (Inductively Coupled Plasma).
  • the average particle diameter of the non-conductive particles used in the present invention is preferably 0.1 to 2 ⁇ m, more preferably 0.1 to 1 ⁇ m, and particularly preferably 0.1 to 0.8 ⁇ m.
  • the average particle diameter of the non-conductive particles is in the range of 0.1 to 0.8 ⁇ m because the dispersion, the ease of coating, and the controllability of the voids are excellent.
  • the average particle diameter can be obtained from an average value obtained by observing an electron microscope and calculating (a + b) / 2 by taking the longest side of the particle image as a and the shortest side as b for 100 or more particles. .
  • the average circularity of the nonconductive particles used in the present invention is preferably 0.900 to 0.995, more preferably 0.91 to 0.98, and particularly preferably 0.92 to 0.97.
  • the BET specific surface area of the non-conductive particles used in the present invention is specifically 0.9 to 200 m 2 / from the viewpoint of suppressing aggregation of the non-conductive particles and optimizing the fluidity of the porous membrane slurry. g is preferable, and 1.5 to 150 m 2 / g is more preferable.
  • the particle size distribution of the non-conductive particles is preferably 1.00 to 1.4, more preferably 1.00 to 1.3, and particularly preferably 1.00 to 1.2.
  • a predetermined gap can be maintained between the non-conductive particles, so that the lithium migration is inhibited and the resistance is increased in the secondary battery of the present invention. This can be suppressed.
  • the particle size distribution of the non-conductive particles is obtained by measuring the particle size with a laser diffraction scattering particle size distribution measuring device (LS230) manufactured by Beckman Co., Ltd., and then obtaining the volume average particle size V and the number average particle size. It can be determined by the ratio V / N with N.
  • the binder used in the present invention includes acrylic polymer particles A having sulfonic acid groups and acrylic polymer particles B having epoxy groups.
  • the binder containing the acrylic polymer particles A and the acrylic polymer particles B gelation of the porous film slurry can be prevented, so that a uniform porous film can be formed. .
  • the acrylic polymer particle A having a sulfonic acid group includes a monomer unit having a sulfonic acid group.
  • the polymer as the acrylic polymer particle A includes a monomer unit having a sulfonic acid group.
  • Examples of monomers having a sulfonic acid group include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylic acid-2-ethyl sulfonate, 2-acrylamido-2-methyl.
  • Examples thereof include propanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, sodium styrenesulfonate, and the like.
  • the content ratio of the monomer unit having a sulfonic acid group in the acrylic polymer particle A is preferably 0.3 to 10% by mass, more preferably 1.3 to 9% by mass.
  • the binder can be provided with a good binding property, and the non-conductive particles are detached from the porous film (powder off). ) Can be suppressed.
  • the content ratio of the sulfonic acid group in the acrylic polymer particles A is preferably 0.04 to 5.8% by mass, more preferably 0.1 to 4% by mass, and particularly preferably 0.5 to 3.5% by mass. is there.
  • the content ratio of the sulfonic acid group in the acrylic polymer particles A is within the above range, the increase in the viscosity of the porous film slurry can be prevented, and the coating property of the porous film slurry can be kept good.
  • the reactivity with the epoxy group of the acrylic polymer particle B mentioned later becomes high. Furthermore, the dispersibility of the nonconductive particles in the porous membrane slurry is improved.
  • the acrylic polymer particle A preferably further contains a (meth) acrylonitrile monomer unit in addition to the monomer unit having a sulfonic acid group.
  • the content ratio of the (meth) acrylonitrile monomer unit in the acrylic polymer particles A is preferably 2.5 to 40% by mass, more preferably 3 to 37% by mass, and particularly preferably 5 to 35% by mass.
  • the strength of the binder is improved, so that a secondary battery having excellent cycle characteristics can be manufactured.
  • the acrylic polymer particle A having a sulfonic acid group further contains a (meth) acrylic acid ester monomer unit in addition to the monomer unit.
  • the content ratio of the (meth) acrylic acid ester monomer unit in the acrylic polymer particles A is preferably 60 to 97.5% by mass, more preferably 62 to 96% by mass, and particularly preferably 65 to 95% by mass. .
  • the binder does not elute into the electrolytic solution of the secondary battery and exhibits an appropriate swelling property to the electrolytic solution.
  • the lithium ion conductivity can be kept good. As a result, the cycle characteristics of the secondary battery can be improved.
  • Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2- Acrylic acid alkyl esters such as ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate , Pentyl methacrylate, hexyl methacrylate, heptyl
  • non-carbonylic oxygen atoms are shown because they exhibit lithium ion conductivity by moderate swelling into the electrolyte without eluting into the electrolyte, and in addition, they are less likely to cause bridging aggregation by the polymer in the dispersion of the active material.
  • the acrylic polymer particles A are in addition to the above monomer units (monomer units having a sulfonic acid group, (meth) acrylonitrile monomer units, and (meth) acrylic acid ester monomer units). It is preferable to contain other monomer units copolymerizable with.
  • the content ratio of the other monomer units in the acrylic polymer particles A is preferably 0.1 to 10% by mass, more preferably 0.1 to 5% by mass. When the content ratio of the other monomer units in the acrylic polymer particles A is in the above range, the dispersibility of the particles does not decrease, and a porous film can be formed uniformly.
  • styrene-based monomers such as styrene, chlorostyrene, vinyltoluene, t-butylstyrene, vinylbenzoic acid, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, ⁇ -methylstyrene, and divinylbenzene.
  • Acrylic acid methacrylic acid, crotonic acid, 2-ethylacrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxyacrylic acid, ⁇ -diamino
  • An ethylenically unsaturated carboxylic acid having a monocarboxylic acid such as acrylic acid; maleic acid, fumaric acid, itaconic acid, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, and Dicarboxylic acid such as maleate ester Ethylenically unsaturated carboxylic acids and derivatives thereof; olefins such as ethylene and propylene; diene monomers such as butadiene and isoprene; halogen atom-containing monomers such as vinyl chloride and vinylidene chloride; vinyl acetate
  • the acrylic polymer particle B having an epoxy group comprises a monomer unit having an epoxy group.
  • the polymer as the acrylic polymer particle B includes a monomer unit having an epoxy group.
  • Monomers having an epoxy group include unsaturated glycidyl ethers such as vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o-allylphenyl glycidyl ether; butadiene monoepoxide, chloroprene monoepoxide, 4,5-epoxy- Diene or polyene monoepoxides such as 2-pentene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene; 3,4-epoxy-1-butene, 1,2 Alkenyl epoxides such as epoxy-5-hexene and 1,2-epoxy-9-decene; glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, glycidyl-4-heptenoate, glycid
  • the content ratio of the monomer unit having an epoxy group in the acrylic polymer particle B is preferably 0.3 to 8% by mass, more preferably 0.3 to 5% by mass.
  • the binder can be provided with a favorable binding property, and the non-conductive particles are detached from the porous film (powder off). Can be suppressed.
  • the content ratio of the epoxy group in the acrylic polymer particle B is preferably 0.03 to 3.0% by mass, more preferably 0.1 to 2.5% by mass, and particularly preferably 0.1 to 1.5% by mass. It is.
  • the content ratio of the epoxy group in the acrylic polymer particles B is within the above range, the viscosity of the porous film slurry can be prevented from increasing, and the coating property of the porous film slurry can be kept good.
  • strength of a porous film improves.
  • Acrylic polymer particles B include (meth) acrylonitrile monomer units, (meth) acrylic acid ester monomer units and other monomer units copolymerizable therewith, in addition to monomer units having an epoxy group. It is preferable that it is further included.
  • the content ratio of the (meth) acrylonitrile monomer unit in the acrylic particles B, the content ratio of the (meth) acrylic acid ester monomer unit, and the content ratio of other monomer units copolymerizable therewith are the above-mentioned acrylic. It is the same as the content ratio in the polymer particle A.
  • each monomer can illustrate the monomer similar to the monomer in the acrylic polymer particle A mentioned above.
  • the weight ratio of the acrylic polymer particles A to the acrylic polymer particles B is preferably 0.3 to 3, more preferably 0.4 to 3, particularly preferably 0. .5-2.
  • the acrylic polymer particles A and the acrylic polymer particles B are used in the state of a dispersion or dissolved solution dispersed in a dispersion medium (water or organic solvent) (hereinafter referred to as “polymer particle dispersion A” and It may be described as “polymer particle dispersion B”).
  • a dispersion medium water or organic solvent
  • an organic solvent such as N-methylpyrrolidone (NMP) is used.
  • the average particle diameter of dispersed acrylic polymer particles A and acrylic polymer particles B (dispersed particles) The diameter is preferably 0.05 to 0.5 ⁇ m, more preferably 0.07 to 0.4 ⁇ m, and most preferably 0.1 to 0.25 ⁇ m.
  • the average particle diameter of the acrylic polymer particles A and the acrylic polymer particles B is in the above range, the strength and flexibility of the obtained porous film are improved.
  • the solid content concentration of the dispersion is usually 15 to 70% by mass, preferably 20 to 65% by mass, More preferably, it is 30 to 60% by mass. When the solid content concentration is within this range, workability in producing the porous membrane slurry is good.
  • the glass transition temperature (Tg) of the acrylic polymer particles A and B used in the present invention is preferably ⁇ 50 to 25 ° C., more preferably ⁇ 45 to 15 ° C., and particularly preferably ⁇ 40 to 5 ° C. Since the porous film of the present invention has excellent strength and flexibility when the Tg of the acrylic polymer particle A and the acrylic polymer particle B is in the above range, the output characteristics of the secondary battery using the porous film are Can be improved.
  • the glass transition temperatures of the acrylic polymer particles A and the acrylic polymer particles B can be prepared by combining various monomers.
  • the production method of the acrylic polymer particles A and the acrylic polymer particles B used in the present invention is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method may be used. it can.
  • the polymerization reaction any reaction such as ionic polymerization, radical polymerization, and living radical polymerization can be used.
  • the polymerization initiator used for the polymerization include lauroyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butyl peroxypivalate, 3,3,5-trimethylhexanoyl peroxide, and the like.
  • Organic peroxides, azo compounds such as ⁇ , ⁇ ′-azobisisobutyronitrile, ammonium persulfate, potassium persulfate, and the like.
  • Acrylic polymer particles A and acrylic polymer particles B used in the present invention have a particulate metal removal step of removing particulate metals contained in the polymer particle dispersion A and the polymer particle dispersion B in the production process. It is preferable that it was obtained through this.
  • the content of the particulate metal component contained in the polymer particle dispersion A and the polymer particle dispersion B is 10 ppm or less, thereby preventing metal ion cross-linking between the polymers in the porous membrane slurry over time, and the viscosity. The rise can be prevented. Furthermore, there is little concern about self-discharge increase due to internal short circuit of the secondary battery or dissolution / precipitation during charging, and the cycle characteristics and safety of the battery are improved.
  • the method for removing the particulate metal component from the polymer particle dispersion A and the polymer particle dispersion B in the particulate metal removal step is not particularly limited.
  • the removal method include a removal method by centrifugation, a removal method by magnetic force, and the like.
  • the method of removing by magnetic force is preferable.
  • the method for removing by magnetic force is not particularly limited as long as the metal component can be removed. However, in consideration of productivity and removal efficiency, it is preferably in the production line of acrylic polymer particles A and acrylic polymer particles B. This is done by placing a magnetic filter.
  • the method for producing the binder used in the present invention is not particularly limited, and is produced by mixing the polymer particle dispersion A and the polymer particle dispersion B described above.
  • the mixing device is not particularly limited as long as it can uniformly mix the polymer particle dispersion A and the polymer particle dispersion B.
  • a mixing device such as a stirring type, a shaking type, and a rotary type is used.
  • a method is mentioned.
  • a method using a dispersion kneader such as a homogenizer, a ball mill, a sand mill, a roll mill, a planetary mixer, and a planetary kneader can be used.
  • the content ratio of the acrylic polymer particles A in the binder is preferably 30 to 75% by mass, more preferably 33 to 66% by mass, and the content ratio of the acrylic polymer particles B in the binder is preferably 25 to 70% by mass. More preferably, the content is 33 to 66% by mass.
  • the content ratio of the acrylic polymer particles A and the acrylic polymer particles B in the binder is in the above range, the binding force is good, and the binder is dispersed without thickening, so the smoothness of the porous film is also improved. Excellent.
  • the weight ratio of the sulfonic acid groups in the acrylic polymer particles A to the epoxy groups in the acrylic polymer particles B in the binder (sulfonic acid groups / epoxy groups) is preferably 0.2 to 3, more preferably 0.3 to 3. Particularly preferred is 0.3 to 2.
  • the weight ratio of the sulfonic acid group to the epoxy group in the binder (sulfonic acid group / epoxy group) is within the above range, gelation of the porous film slurry can be prevented, and the coating property of the porous film slurry can be improved. The strength of the obtained porous membrane is improved.
  • the average particle size of the binder is preferably 0.05 to 0.5 ⁇ m, more preferably 0.07 to 0.4 ⁇ m, and particularly preferably 0.10 to 0.25 ⁇ m.
  • the average particle size can be determined by measuring the particle size distribution by laser diffraction.
  • the content ratio of the binder per 100% by mass of the total solid content of the porous membrane slurry is preferably 0.5 to 20% by mass, more preferably 5 to 20% by mass, and particularly preferably 5 to 15% by mass.
  • solvent As a solvent used for the porous membrane slurry, either water or an organic solvent can be used.
  • organic solvents include cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as acetone, ethyl methyl ketone, diisopropyl ketone, cyclohexanone, methylcyclohexane, and ethylcyclohexane.
  • cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane
  • aromatic hydrocarbons such as toluene, xylene, and ethylbenzene
  • ketones such as acetone, ethyl methyl ketone, diisopropyl ketone, cyclohexanone, methylcyclohexane, and ethylcyclo
  • Chlorinated aliphatic hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride; Esters such as ethyl acetate, butyl acetate, ⁇ -butyrolactone and ⁇ -caprolactone; Acylonitriles such as acetonitrile and propionitrile; Tetrahydrofuran, Ethers such as ethylene glycol diethyl ether: alcohols such as methanol, ethanol, isopropanol, ethylene glycol and ethylene glycol monomethyl ether; N-methyl Amides such as lupyrrolidone and N, N-dimethylformamide are exemplified.
  • solvents may be used alone or as a mixed solvent by mixing two or more of them.
  • a solvent having excellent dispersibility of non-conductive particles and having a low boiling point and high volatility is preferable because it can be removed in a short time and at a low temperature.
  • acetone, toluene, cyclohexanone, cyclopentane, tetrahydrofuran, cyclohexane, xylene, water, N-methylpyrrolidone, or a mixed solvent thereof is preferable.
  • the porous membrane slurry may further contain optional components.
  • optional components include inorganic particles, dispersants, leveling agents, antioxidants, binders other than the above binders, thickeners, antifoaming agents, and electrolytic solution additives having functions such as suppression of electrolytic solution decomposition. And the like. These are not particularly limited as long as they do not affect the battery reaction.
  • the inorganic particles for example, various inorganic particles such as aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, aluminum nitride, calcium fluoride, barium fluoride talc, and montmorillonite can be used. In particular, non-spherical atypical particles are preferred.
  • the content ratio of the inorganic particles per 100% by mass of the total solid content of the porous membrane slurry is 20% by mass or less, more preferably 10% by mass or less. When the content ratio of the inorganic particles is within this range, a porous film having high strength and good lithium ion permeability can be obtained.
  • the dispersant examples include anionic compounds, cationic compounds, nonionic compounds, and polymer compounds.
  • a dispersing agent is selected according to the nonelectroconductive particle to be used.
  • the content ratio of the dispersing agent per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less. When the content ratio of the dispersant is within this range, the coating property of the porous membrane slurry of the present invention is good, and a uniform porous membrane can be obtained.
  • leveling agents include surfactants such as alkyl surfactants, silicone surfactants, fluorine surfactants, and metal surfactants.
  • the content ratio of the surfactant per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less.
  • the antioxidant examples include a phenol compound, a hydroquinone compound, an organic phosphorus compound, a sulfur compound, a phenylenediamine compound, and a polymer type phenol compound.
  • the polymer type phenol compound is a polymer having a phenol structure in the molecule, and a polymer type phenol compound having a weight average molecular weight of 200 to 1000, preferably 600 to 700 is preferably used.
  • the content ratio of the antioxidant per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less. When the content ratio of the antioxidant is within this range, the cycle life of the battery is excellent.
  • binders other than the binder examples include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylic acid derivatives, polyacrylonitrile derivatives, and soft polymers used in electrode binders described later. Can be used.
  • the content rate of binder other than the said binder per 100 mass% of total solid content of a porous membrane slurry is 10 mass% or less. When the content ratio of the binder is within this range, the adhesion between the porous film of the present invention and the electrode active material layer and organic separator described later is good.
  • thickeners include cellulosic polymers such as carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, and ammonium salts and alkali metal salts thereof; (modified) poly (meth) acrylic acid and ammonium salts and alkali metal salts thereof; ) Polyvinyl alcohols such as polyvinyl alcohol, copolymers of acrylic acid or acrylate and vinyl alcohol, maleic anhydride or copolymers of maleic acid or fumaric acid and vinyl alcohol; polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, modified Examples thereof include polyacrylic acid, oxidized starch, phosphoric acid starch, casein, various modified starches, acrylonitrile-butadiene copolymer hydride, and the like.
  • cellulosic polymers such as carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, and ammonium salts and alkali metal salts thereof; (modified) poly (meth) acrylic acid and ammonium salt
  • the content ratio of the thickener per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less.
  • the content of the thickener is within this range, the coating property of the porous membrane slurry of the present invention and the adhesion between the porous membrane of the present invention and the electrode active material layer and organic separator described later are good.
  • “(modified) poly” means “unmodified poly” or “modified poly”
  • (meth) acryl” means “acryl” or “methacryl”.
  • the antifoaming agent metal soaps, polysiloxanes, polyethers, higher alcohols, perfluoroalkyls and the like are used.
  • the content ratio of the antifoaming agent per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less.
  • the electrolytic solution additive vinylene carbonate used in an electrode slurry and an electrolytic solution described later can be used.
  • the content ratio of the electrolytic solution additive per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less.
  • nanoparticles such as fumed silica and fumed alumina.
  • the total content of the above-mentioned arbitrary components per 100% by mass of the total solid content of the porous membrane slurry is preferably 40% by mass or less, more preferably 20% by mass or less. However, if the total of the non-conductive particles, binder, and optional components (excluding inorganic particles and binder) is less than 100% by mass, the content of the binder as an optional component is increased appropriately. And a composition can be obtained.
  • the solid content concentration of the porous membrane slurry is not particularly limited as long as the slurry can be applied and immersed and has a fluid viscosity, but is generally about 10 to 50% by mass.
  • Components other than the solid content are components that volatilize in the drying step, and include, in addition to the solvent, for example, a medium in which these are dissolved or dispersed during preparation and addition of non-conductive particles and a binder.
  • the production method of the secondary battery porous membrane slurry is not particularly limited, and is produced by mixing the non-conductive particles, the binder, the solvent, and optional components added as necessary.
  • the non-conductive particles are highly dispersed regardless of the mixing method and mixing order.
  • a membrane slurry can be obtained.
  • the mixing apparatus a mixing apparatus similar to the mixing apparatus used for the production of the binder described above can be used. Among them, it is particularly preferable to use a high dispersion apparatus such as a bead mill, a roll mill, or a fill mix that can add a high dispersion share.
  • the viscosity of the porous membrane slurry is preferably 10 to 10,000 mPa ⁇ s, more preferably 50 to 500 mPa ⁇ s, from the viewpoints of uniform coatability and slurry aging stability.
  • the viscosity is a value measured using a B-type viscometer at 25 ° C. and a rotation speed of 60 rpm.
  • the secondary battery porous membrane of the present invention (hereinafter sometimes referred to as “porous membrane”) is formed by forming the above-described secondary battery porous membrane slurry into a film and drying it. .
  • the porous film is used by being laminated on an organic separator or an electrode, or used as an organic separator itself.
  • a porous film slurry containing the above non-conductive particles, a binder, a solvent and an optional component is applied on a predetermined substrate (positive electrode, negative electrode or organic separator).
  • the porous membrane of the present invention is manufactured by the above-described methods (I) to (III), and the detailed manufacturing method will be described below.
  • the porous membrane slurry of the present invention is produced by applying a porous membrane slurry onto a predetermined substrate (positive electrode, negative electrode or organic separator) and drying.
  • the method for applying the slurry onto the substrate is not particularly limited, and examples thereof include a doctor blade method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method.
  • the gravure method is preferable in that a uniform porous film can be obtained.
  • drying method examples include drying with warm air, hot air, low-humidity air, vacuum drying, and drying by irradiation with (far) infrared rays or electron beams.
  • the drying temperature can vary depending on the type of solvent used. In order to completely remove the solvent, for example, when a low-volatility solvent such as N-methylpyrrolidone is used, it is preferably dried at a high temperature of 120 ° C. or higher with a blower-type dryer. Conversely, when a highly volatile solvent is used, it can be dried at a low temperature of 100 ° C. or lower. When forming a porous film on the organic separator mentioned later, since it is necessary to dry without causing shrinkage of the organic separator, drying at a low temperature of 100 ° C. or lower is preferable.
  • the porous membrane of the present invention is produced by immersing the porous membrane slurry in a substrate (positive electrode, negative electrode or organic separator) and drying.
  • the method for immersing the slurry in the substrate is not particularly limited, and for example, the slurry can be immersed by dip coating with a dip coater or the like.
  • Examples of the drying method include the same methods as the drying method in the method (I) described above.
  • a porous film slurry is applied on a release film and formed into a film, thereby producing a porous film formed on the release film.
  • the obtained porous film is transferred onto a substrate (positive electrode, negative electrode or organic separator).
  • a coating method the same method as the coating method in the above-mentioned method (I) can be mentioned.
  • the transfer method is not particularly limited.
  • the porous film obtained by the methods (I) to (III) is then subjected to pressure treatment using a die press or a roll press, if necessary, and a substrate (positive electrode, negative electrode or organic separator) and porous film. It is also possible to improve the adhesion. However, at this time, if the pressure treatment is excessively performed, the porosity of the porous film may be impaired, so the pressure and the pressure time are controlled appropriately.
  • the film thickness of the porous film is not particularly limited and is appropriately set according to the use or application field of the porous film. However, if the film is too thin, a uniform film cannot be formed. Since the capacity per volume (weight) decreases, 0.5 to 50 ⁇ m is preferable, and 0.5 to 10 ⁇ m is more preferable.
  • the porous film of the present invention is formed on the surface of a substrate (positive electrode, negative electrode or organic separator) and is particularly preferably used as a protective film or separator for an electrode active material layer described later.
  • the porous film of the present invention may be formed on any surface of the positive electrode, negative electrode or organic separator of the secondary battery, or may be formed on all of the positive electrode, negative electrode and organic separator.
  • Secondary battery electrode Examples of the secondary battery include a lithium ion secondary battery and a nickel metal hydride secondary battery. Among these, since the lithium ion secondary battery is preferable because safety improvement is most demanded and the effect of introducing the porous film is the highest, a case where it is used for a lithium ion secondary battery will be described below.
  • the secondary battery electrode of the present invention includes a current collector, an electrode active material layer comprising an electrode active material and a binder, which is attached to the current collector, and a laminate on the surface of the electrode active material layer.
  • the above-described secondary battery porous membrane is described below.
  • the electrode active material layer containing the electrode active material and the electrode binder is attached to the current collector, and the surface of the electrode active material layer has the above-mentioned secondary battery porosity.
  • a film is laminated.
  • the electrode active material used for the electrode for the lithium ion secondary battery is not particularly limited as long as it can reversibly insert and release lithium ions by applying a potential in the electrolyte, and can be an inorganic compound or an organic compound.
  • Electrode active materials (positive electrode active materials) for lithium ion secondary battery positive electrodes are broadly classified into those made of inorganic compounds and those made of organic compounds.
  • Examples of the positive electrode active material made of an inorganic compound include transition metal oxides, composite oxides of lithium and transition metals, and transition metal sulfides.
  • As the transition metal Fe, Co, Ni, Mn and the like are used.
  • the inorganic compound used for the positive electrode active material include LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiFePO 4 , LiFeVO 4, and other lithium-containing composite metal oxides; TiS 2 , TiS 3 , non- Transition metal sulfides such as crystalline MoS 2 ; transition metal oxides such as Cu 2 V 2 O 3 , amorphous V 2 O—P 2 O 5 , MoO 3 , V 2 O 5 , V 6 O 13 It is done. These compounds may be partially element-substituted.
  • the positive electrode active material made of an organic compound for example, a conductive polymer such as polyacetylene or poly-p-phenylene can be used.
  • An iron-based oxide having poor electrical conductivity may be used as an electrode active material covered with a carbon material by allowing a carbon source material to be present during reduction firing. These compounds may be partially element-substituted.
  • the positive electrode active material for a lithium ion secondary battery may be a mixture of the above inorganic compound and organic compound.
  • the particle diameter of the positive electrode active material is appropriately selected in consideration of the arbitrary constituent requirements of the battery. From the viewpoint of improving battery characteristics such as rate characteristics and cycle characteristics, the 50% volume cumulative diameter is usually 0.1. It is ⁇ 50 ⁇ m, preferably 1 to 20 ⁇ m. When the 50% volume cumulative diameter is within this range, a secondary battery having a large charge / discharge capacity can be obtained, and handling of the slurry for electrodes and the electrodes is easy.
  • the 50% volume cumulative diameter can be determined by measuring the particle size distribution by laser diffraction.
  • Examples of electrode active materials (negative electrode active materials) for negative electrodes of lithium ion secondary batteries include carbonaceous materials such as amorphous carbon, graphite, natural graphite, mesocarbon microbeads, pitch-based carbon fibers, and high conductivity such as polyacene. Molecular compounds and the like.
  • carbonaceous materials such as amorphous carbon, graphite, natural graphite, mesocarbon microbeads, pitch-based carbon fibers, and high conductivity such as polyacene. Molecular compounds and the like.
  • metals such as silicon, tin, zinc, manganese, iron, nickel, alloys thereof, oxides or sulfates of the metals or alloys are used.
  • lithium alloys such as lithium metal, Li—Al, Li—Bi—Cd, and Li—Sn—Cd, lithium transition metal nitride, silicone, and the like can be used.
  • the electrode active material a material obtained by attaching a conductivity imparting material to the surface by a mechanical modification method can be used.
  • the particle size of the negative electrode active material is appropriately selected in consideration of the other structural requirements of the battery. From the viewpoint of improving battery characteristics such as initial efficiency, rate characteristics, and cycle characteristics, a 50% volume cumulative diameter is usually The thickness is 1 to 50 ⁇ m, preferably 15 to 30 ⁇ m.
  • the electrode active material layer includes a binder (hereinafter sometimes referred to as “electrode binder”) in addition to the electrode active material.
  • electrode binder a binder
  • the binding property of the electrode active material layer in the electrode is improved, the strength against the mechanical force applied during the process of winding the electrode is increased, and the electrode active material in the electrode is increased. Since the material layer is less likely to be detached, the risk of a short circuit due to the desorbed material is reduced.
  • Various resin components can be used as the electrode binder.
  • polyethylene polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyacrylic acid derivatives, polyacrylonitrile derivatives, and the like can be used. These may be used alone or in combination of two or more.
  • the binder used for the porous film of this invention can also be used as a binder for electrodes.
  • the soft polymer illustrated below can also be used as a binder for electrodes.
  • Acrylic acid such as polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, butyl acrylate / styrene copolymer, butyl acrylate / acrylonitrile copolymer, butyl acrylate / acrylonitrile / glycidyl methacrylate copolymer
  • an acrylic soft polymer which is a homopolymer of a methacrylic acid derivative or a copolymer with a monomer copolymerizable therewith;
  • Isobutylene-based soft polymers such as polyisobutylene, isobutylene-isoprene rubber, isobutylene-styrene copolymer;
  • Olefinic soft polymers of Vinyl-based soft polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, vinyl acetate / styrene copolymer; Epoxy-based soft polymers such as polyethylene oxide, polypropylene oxide, epichlorohydrin rubber; Fluorine-containing soft polymers such as vinylidene fluoride rubber and tetrafluoroethylene-propylene rubber; Examples thereof include other soft polymers such as natural rubber, polypeptide, protein, polyester-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, and polyamide-based thermoplastic elastomer. These soft polymers may have a cross-linked structure or may have a functional group introduced by modification.
  • the amount of the electrode binder in the electrode active material layer is preferably from 0.1 to 5 parts by weight, more preferably from 0.2 to 4 parts by weight, particularly preferably from 0.1 to 100 parts by weight of the electrode active material. 5 to 3 parts by mass.
  • the amount of the electrode binder in the electrode active material layer is within the above range, it is possible to prevent the active material from being detached from the electrode without inhibiting the battery reaction.
  • the electrode binder is prepared as a solution or dispersion to produce an electrode.
  • the viscosity at that time is usually in the range of 1 to 300,000 mPa ⁇ s, preferably 50 to 10,000 mPa ⁇ s.
  • the viscosity is a value measured using a B-type viscometer at 25 ° C. and a rotation speed of 60 rpm.
  • the electrode active material layer may contain an optional additive such as a conductivity-imparting material or a reinforcing material in addition to the electrode active material and the electrode binder.
  • an optional additive such as a conductivity-imparting material or a reinforcing material in addition to the electrode active material and the electrode binder.
  • a conductivity-imparting material conductive carbon such as acetylene black, ketjen black, carbon black, graphite, vapor-grown carbon fiber, and carbon nanotube can be used. Examples thereof include carbon powders such as graphite, and fibers and foils of various metals.
  • the reinforcing material various inorganic and organic spherical, plate-like, rod-like or fibrous fillers can be used.
  • the conductivity imparting material By using the conductivity imparting material, the electrical contact between the electrode active materials can be improved, and the discharge rate characteristics can be improved when used in a lithium ion secondary battery.
  • the amount of the conductivity-imparting material and the reinforcing material used is usually 0 to 20 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the electrode active material.
  • an isothiazoline-based compound or a chelate compound may be included in the electrode active material layer.
  • the electrode active material layer can be formed by adhering a slurry containing an electrode active material, an electrode binder and a solvent (hereinafter also referred to as “electrode slurry”) to a current collector.
  • the solvent is not particularly limited as long as it dissolves or disperses the electrode binder, but preferably dissolves.
  • the electrode binder is adsorbed on the surface of the electrode active material or any additive, thereby stabilizing the dispersion of the electrode active material.
  • organic solvents include cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; ketones such as ethyl methyl ketone and cyclohexanone; ethyl acetate, butyl acetate, ⁇ -butyrolactone, ⁇ -Esters such as caprolactone; Acylonitriles such as acetonitrile and propionitrile; Ethers such as tetrahydrofuran and ethylene glycol diethyl ether; Alcohols such as methanol, ethanol, isopropanol, ethylene glycol and ethylene glycol monomethyl ether; N-methyl Amides such as pyrrolidone and N, N-dimethylformamide are exemplified. These solvents may be used alone or in admixture of two or more and
  • the electrode slurry may further contain additives that exhibit various functions such as a thickener.
  • a thickener a polymer soluble in the solvent used for the electrode slurry is used.
  • the thickener exemplified in the porous membrane slurry of the present invention can be used.
  • the amount of the thickener used is preferably 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the electrode active material. When the use amount of the thickener is within the above range, the coating property of the electrode slurry and the adhesion to the current collector are good.
  • the electrode slurry contains trifluoropropylene carbonate, vinylene carbonate, catechol carbonate, 1,6-dioxaspiro [4,4] nonane-2,7 in order to increase the stability and life of the battery.
  • -Dione, 12-crown-4-ether and the like can be used. These may be used by being contained in an electrolyte solution described later.
  • the amount of the solvent in the electrode slurry is adjusted to a viscosity suitable for coating depending on the type of the electrode active material, the electrode binder, and the like. Specifically, the concentration of solids in the electrode slurry is preferably 30 to 90% by mass, and more preferably combined with any additive such as an electrode active material, an electrode binder, and a conductivity-imparting material. Is used by adjusting the amount to 40 to 80% by mass.
  • the electrode slurry is obtained by mixing an electrode active material, an electrode binder, an optional additive such as a conductivity imparting agent added as necessary, and a solvent using a mixer. Mixing may be performed by supplying the above components all at once to a mixer.
  • electrode active materials, electrode binders, conductivity-imparting materials and thickeners as constituents of electrode slurries
  • conductivity is imparted by mixing the conductivity-imparting materials and thickeners in a solvent. It is preferable to disperse the material in the form of fine particles, and then add a binder for the electrode and an electrode active material and further mix, since the dispersibility of the slurry is improved.
  • a ball mill, sand mill, pigment disperser, crusher, ultrasonic disperser, homogenizer, planetary mixer, Hobart mixer, etc. can be used. It is preferable because aggregation of the resin can be suppressed.
  • the particle size of the electrode slurry is preferably 35 ⁇ m or less, more preferably 25 ⁇ m or less.
  • the conductivity imparting material is highly dispersible and a homogeneous electrode can be obtained.
  • the current collector is not particularly limited as long as it is an electrically conductive and electrochemically durable material. From the viewpoint of having heat resistance, for example, iron, copper, aluminum, nickel, stainless steel, etc. Metal materials such as titanium, tantalum, gold, and platinum are preferable. Among these, aluminum is particularly preferable for the positive electrode of the lithium ion secondary battery, and copper is particularly preferable for the negative electrode of the lithium ion secondary battery.
  • the shape of the current collector is not particularly limited, but a sheet shape having a thickness of about 0.001 to 0.5 mm is preferable. In order to increase the adhesive strength of the electrode active material layer, the current collector is preferably used after roughening in advance.
  • Examples of the roughening method include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method.
  • a mechanical polishing method an abrasive cloth paper with a fixed abrasive particle, a grindstone, an emery buff, a wire brush provided with a steel wire or the like is used.
  • an intermediate layer may be formed on the surface of the current collector in order to increase the adhesive strength and conductivity of the electrode active material layer.
  • the method for producing the electrode active material layer may be any method in which the electrode active material layer is bound in layers on at least one surface, preferably both surfaces of the current collector.
  • the electrode slurry is applied to a current collector and dried, and then heat-treated at 120 ° C. or higher for 1 hour or longer to form an electrode active material layer.
  • the method for applying the electrode slurry to the current collector is not particularly limited. Examples thereof include a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method.
  • Examples of the drying method include drying by warm air, hot air, low-humidity air, vacuum drying, and drying by irradiation with (far) infrared rays or electron beams.
  • the porosity of the electrode active material layer is lower by pressure treatment using a mold press or a roll press.
  • a preferable range of the porosity is 5 to 15%, more preferably 7 to 13%. If the porosity is too high, charging efficiency and discharging efficiency are deteriorated. When the porosity is too low, there are problems that it is difficult to obtain a high volume capacity, or that the electrode active material layer is easily peeled off and is likely to be defective. Further, when a curable polymer is used, it is preferably cured.
  • the thickness of the electrode active material layer is usually 5 to 300 ⁇ m, preferably 10 to 250 ⁇ m, for both the positive electrode and the negative electrode.
  • the secondary battery electrode of the present invention is manufactured by laminating the secondary battery porous film of the present invention on the surface of the electrode active material layer of the current collector in which the electrode active material layer is bound in a layered manner.
  • the laminating method is not particularly limited, and examples thereof include the methods (I) to (III) described in the above method for producing a porous film.
  • the secondary battery separator of the present invention comprises an organic separator and the above-described secondary battery porous film laminated on the organic separator. That is, the secondary battery separator of the present invention is formed by laminating the above-described secondary battery porous film on an organic separator.
  • Organic separator As an organic separator for a lithium ion secondary battery, known ones such as a polyolefin resin such as polyethylene and polypropylene and a separator containing an aromatic polyamide resin are used.
  • a porous membrane having a fine pore size, having no electron conductivity and ionic conductivity and high resistance to organic solvents is used.
  • a microporous film made of a resin such as a mixture or a copolymer thereof, polyethylene terephthalate, polycycloolefin, polyether sulfone, polyamide, polyimide, polyimide amide, polyaramid, polycycloolefin, nylon, polytetrafluoroethylene
  • a microporous membrane made of a resin such as the above, or a woven fabric of polyolefin fibers, a nonwoven fabric thereof, an aggregate of insulating substance particles, or the like.
  • the thickness of the organic separator is usually 0.5 to 40 ⁇ m, preferably 1 to 30 ⁇ m, more preferably 1 to 20 ⁇ m. Within this range, the resistance due to the organic separator in the battery is reduced. Moreover, the workability
  • examples of the polyolefin-based resin used as the material for the organic separator include homopolymers such as polyethylene and polypropylene, copolymers, and mixtures thereof.
  • examples of the polyethylene include low density, medium density, and high density polyethylene, and high density polyethylene is preferable from the viewpoint of piercing strength and mechanical strength. These polyethylenes may be mixed in two or more types for the purpose of imparting flexibility.
  • the polymerization catalyst used for these polyethylenes is not particularly limited, and examples thereof include Ziegler-Natta catalysts, Phillips catalysts, and metallocene catalysts.
  • the viscosity average molecular weight of polyethylene is preferably 100,000 to 12 million, and more preferably 200,000 to 3 million.
  • polypropylene include homopolymers, random copolymers, and block copolymers, and one kind or a mixture of two or more kinds can be used.
  • the polymerization catalyst is not particularly limited, and examples thereof include Ziegler-Natta catalysts and metallocene catalysts.
  • the stereoregularity is not particularly limited, and isotactic, syndiotactic or atactic can be used.
  • isotactic polypropylene because it is inexpensive.
  • an appropriate amount of a polyolefin other than polyethylene or polypropylene, and an additive such as an antioxidant or a nucleating agent may be added to the polyolefin as long as the effects of the present invention are not impaired.
  • a publicly known one is used. For example, after forming a melt-extruded film of polypropylene and polyethylene, annealing is performed at a low temperature to grow a crystal domain, and in this state, stretching is performed.
  • a wet method in which a microporous film is formed by removing the film that has started to form an island phase by using this solvent or low-molecular solvent with another volatile solvent is selected.
  • a dry method is preferable in that a large void can be easily obtained for the purpose of reducing the resistance.
  • the organic separator used in the present invention may contain any filler or fiber compound for the purpose of controlling strength, hardness, and heat shrinkage.
  • a low molecular weight compound or A coating treatment with a polymer compound an electromagnetic radiation treatment such as ultraviolet rays, or a plasma treatment such as corona discharge / plasma gas may be performed.
  • the coating treatment is preferably performed with a polymer compound containing a polar group such as a carboxylic acid group, a hydroxyl group, and a sulfonic acid group from the viewpoint that the impregnation property of the electrolytic solution is high and the adhesion with the porous film is easily obtained.
  • the secondary battery separator of the present invention is manufactured by laminating the secondary battery porous film of the present invention on the organic separator.
  • the laminating method is not particularly limited, and examples thereof include the methods (I) to (III) described in the above method for producing a porous film.
  • the secondary battery of the present invention includes a positive electrode, a negative electrode, an organic separator, and an electrolytic solution, and the above porous film is laminated on any of the positive electrode, the negative electrode, and the organic separator.
  • Electrode As the electrolytic solution, an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is used.
  • a lithium salt is used as the supporting electrolyte.
  • the lithium salt is not particularly limited, LiPF 6, LiAsF 6, LiBF 4, LiSbF 6, LiAlCl 4, LiClO 4, CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) NLi, and the like.
  • LiPF 6 , LiClO 4 , and CF 3 SO 3 Li that are easily soluble in a solvent and exhibit a high degree of dissociation are preferable. Two or more of these may be used in combination. Since the lithium ion conductivity increases as the supporting electrolyte having a higher degree of dissociation is used, the lithium ion conductivity can be adjusted depending on the type of the supporting electrolyte.
  • the organic solvent used in the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolyte, but dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate.
  • DMC dimethyl carbonate
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • PC propylene carbonate
  • Carbonates such as (BC) and methyl ethyl carbonate (MEC); esters such as ⁇ -butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide; Are preferably used. Moreover, you may use the liquid mixture of these solvents.
  • carbonates are preferable because they have a high dielectric constant and a wide stable potential region. Since the lithium ion conductivity increases as the viscosity of the solvent used decreases, the lithium ion conductivity can be adjusted depending on the type of the solvent.
  • the concentration of the supporting electrolyte in the electrolytic solution is usually 1 to 30% by mass, preferably 5 to 20% by mass.
  • the concentration is usually 0.5 to 2.5 mol / L depending on the type of the supporting electrolyte. If the concentration of the supporting electrolyte is too low or too high, the ionic conductivity tends to decrease. Since the degree of swelling of the polymer particles increases as the concentration of the electrolytic solution used decreases, the lithium ion conductivity can be adjusted by the concentration of the electrolytic solution.
  • a positive electrode and a negative electrode are overlapped with an organic separator, and this is wound into a battery container according to the shape of the battery, put into a battery container, and an electrolytic solution is injected into the battery container. And sealing.
  • the porous film of the present invention is laminated on any one of the positive electrode, the negative electrode, and the organic separator.
  • the method of laminating the porous film of the present invention on the positive electrode, the negative electrode, and the organic separator is as described in the method (I) or (II).
  • an expanded metal, an overcurrent prevention element such as a fuse or a PTC element, a lead plate, or the like can be inserted to prevent an increase in pressure inside the battery and overcharge / discharge.
  • the shape of the battery may be any of a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, a flat shape, and the like.
  • the porous film of the present invention is preferably laminated on the surface of the electrode active material layer of the positive electrode or the negative electrode.
  • the porous film of the present invention By laminating the porous film of the present invention on the surface of the electrode active material layer, even if the organic separator is contracted by heat, a short circuit between the positive electrode and the negative electrode is not caused, and high safety is maintained.
  • the porous membrane of the present invention By laminating the porous membrane of the present invention on the surface of the electrode active material layer, the porous membrane can function as a separator without an organic separator, and a secondary battery can be produced at low cost. become. Further, even when an organic separator is used, higher rate characteristics can be expressed because the holes formed on the separator surface are not filled.
  • a secondary battery porous membrane (organic separator with a porous membrane) or a secondary battery electrode (electrode with a porous membrane) is cut into a width of 10 cm and a length of 1.5 m, and the cut secondary battery porous membrane or secondary battery electrode The thickness was measured at 60 points of 20 points every 3 cm in the width direction and every 5 cm in the length direction using a thickness meter (MH-15M) manufactured by Nikon Corporation. From the standard deviation and average value of the film thickness, Based on the formula, film thickness variation [%] was calculated and evaluated according to the following criteria.
  • x represents an average value of the film thickness
  • n represents the number of measurements.
  • the concentration of LiPF 6 is 1 mol / liter.
  • the solution dissolved in was used. This was enclosed in a 2032 type coin cell. I took the lead from the coin cell, put a thermocouple, and put it in the oven. While applying an alternating current with an amplitude of 10 mV and a frequency of 1 kHz, the temperature was raised to 200 ° C. at a temperature rising rate of 1.6 ° C./min, and the cell resistance during this time was measured to confirm the occurrence of a short circuit.
  • the concentration of LiPF 6 is 1 mol / liter.
  • the solution dissolved in was used. This was enclosed in a 2032 type coin cell.
  • the addition amount [g] of the monomer having an epoxy group added during the polymerization of the acrylic polymer particle B is e
  • the molecular weight is f
  • the molecular weight corresponding to the epoxy group portion is g (43.05)
  • the total amount of the monomer is Assuming that h, the content [% by mass] of the epoxy group (with respect to the total amount of the monomers) in the acrylic polymer particles B is calculated as in the following formula.
  • Content ratio of epoxy group in acrylic polymer particle B (B) (E / f) ⁇ g / h ⁇ 100 [mass%]
  • Example 1 ⁇ (1) Production of seed polymer particle A>
  • 100 parts of styrene, 1.0 part of sodium dodecylbenzenesulfonate, 100 parts of ion-exchanged water, and 0.5 part of potassium persulfate were placed and polymerized at 80 ° C. for 8 hours. Thereby, an aqueous dispersion of seed polymer particles A having an average particle diameter of 60 nm was obtained.
  • styrene 97 parts of styrene, 3 parts of methacrylic acid, 4 parts of t-dodecyl mercaptan, 0.5 part of sodium dodecylbenzenesulfonate, and 100 parts of ion-exchanged water were mixed to disperse the monomer mixture.
  • the body was prepared.
  • the monomer mixture dispersion was continuously added to the mixture for 4 hours to polymerize.
  • the reaction was carried out while maintaining the temperature of the reaction system at 80 ° C. during continuous addition of the dispersion of the monomer mixture. After completion of the continuous addition, the reaction was further continued at 90 ° C. for 3 hours. Thereby, an aqueous dispersion of seed polymer particles B having an average particle diameter of 200 nm was obtained.
  • aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • acrylic polymer particle A the content ratio of the monomer unit having a sulfonic acid group is 4.0%, the content ratio of the sulfonic acid group is 1.56%, the content ratio of the acrylonitrile monomer unit is 14.9%, The content ratio of the (meth) acrylic acid ester monomer unit was 81.1%.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having an epoxy acid group is 3.0%
  • the content ratio of the epoxy acid group is 0.91%
  • the content ratio of the acrylonitrile monomer unit is 15.1%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 81.9%.
  • An aqueous dispersion of non-conductive particles obtained in step (3), an aqueous dispersion of acrylic polymer particles A obtained in step (4), an aqueous dispersion of acrylic polymer particles B obtained in step (5), and A 1% aqueous solution of carboxymethylcellulose is mixed in water so that the solid content weight ratio is 83.1: 6.15: 6.15: 4.6, and water is added as a solvent, followed by dispersion using a bead mill. To obtain a porous membrane slurry. In addition, content of raw materials other than water (total solid content) in the porous membrane slurry was set to 50% by mass.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.7.
  • the positive electrode obtained in the step (7) was cut into a circle having a diameter of 13 mm to obtain a circular positive electrode.
  • the negative electrode obtained in step (8) was cut into a circle having a diameter of 14 mm to obtain a circular negative electrode.
  • the organic separator with a porous film obtained in the step (9) was cut out into a circle having a diameter of 18 mm to obtain a circular organic separator with a porous film.
  • a circular positive electrode is placed on the inner bottom surface of a stainless steel coin-type outer container provided with polypropylene packing, a circular organic separator with a porous film is placed on it, and a circular negative electrode is placed thereon. They were placed and stored in a container.
  • the circular positive electrode was placed so that the surface on the aluminum foil side faced the bottom surface side of the outer container and the surface on the positive electrode active material layer side faced upward.
  • the circular negative electrode was placed so that the surface on the negative electrode active material layer side faced toward the organic separator with a circular porous film and the surface on the copper foil side faced upward.
  • This container was vacuum-dried at 105 ° C. for 24 hours.
  • a lithium ion secondary battery (coin cell CR2032) having a thickness of about 3.2 mm was manufactured.
  • Example 2 After the negative electrode active material layer is completely covered with the porous film slurry obtained in the step (6) of Example 1 on the negative electrode active material layer side surface of the negative electrode obtained in the step (8) of Example 1, after drying was applied so that the thickness of the porous film was 5 ⁇ m to obtain a slurry layer.
  • the slurry layer was dried at 50 ° C. for 10 minutes to form a porous film, and a negative electrode with a porous film was obtained.
  • the obtained negative electrode with a porous film had a layer structure of (porous film) / (negative electrode active material layer) / (copper foil).
  • the uniformity and reliability of the porous film of the obtained negative electrode with a porous film, and powder fall-off property were evaluated. The results are shown in Table 1.
  • an organic separator (single layer polypropylene separator, porosity 55%, thickness 25 ⁇ m, organic separator in the step (9) of Example 1 was used. The same as that used as a).
  • Example 1 a secondary battery was obtained and evaluated in the same manner as in Example 1 except that the above negative electrode with a porous film was used instead of the negative electrode obtained in Step (8) of Example 1. It was. The results are shown in Table 1. In placing the negative electrode with a circular porous film in the outer container, the negative electrode was placed so that the porous film side faced to the circular organic separator side and the copper foil side faced to the upper side.
  • Example 3 Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.7.
  • a polymer aqueous dispersion containing an unreacted monomer was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles A1 was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the acrylic polymer particle A has a sulfonic acid group-containing monomer unit content of 4.0%, a sulfonic acid group content of 1.56%, an acrylonitrile monomer unit content of 7%, )
  • the content of acrylic acid ester monomer units was 89%.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 90.0 parts of n-butyl acrylate, 7.0 parts of acrylonitrile, 3.0 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization After adding 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, the mixture is sufficiently stirred, and then heated to 70 ° C.
  • the content ratio of the monomer unit having an epoxy acid group is 3.0%, the content ratio of the epoxy acid group is 0.91%, the content ratio of the acrylonitrile monomer unit is 7%, ) The content of acrylic acid ester monomer units was 90.0%.
  • Example 4 instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.7.
  • a polymer aqueous dispersion containing an unreacted monomer was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the acrylic polymer particle A has a sulfonic acid group-containing monomer unit content of 4.0%, a sulfonic acid group content of 1.56%, an acrylonitrile monomer unit content of 29.9%, The content ratio of the (meth) acrylic acid ester monomer unit was 66.1%.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 66.8 parts of n-butyl acrylate, 30.2 parts of acrylonitrile, 3.0 parts of glycidyl methacrylate, 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, An aqueous polymer dispersion containing was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having an epoxy acid group is 3.0%
  • the content ratio of the epoxy acid group is 0.91%
  • the content ratio of the acrylonitrile monomer unit is 30.2%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 66.8%.
  • Example 5 The same operation as in Example 1 was performed except that the porous film slurry was produced using the following nonconductive particles instead of the nonconductive particles obtained in the steps (1) to (3) of Example 1.
  • the organic separator with a porous membrane and the secondary battery were obtained and evaluated. The results are shown in Table 1.
  • Example 6 The same operation as in Example 1 was performed except that the porous film slurry was produced using the following nonconductive particles instead of the nonconductive particles obtained in the steps (1) to (3) of Example 1.
  • the organic separator with a porous membrane and the secondary battery were obtained and evaluated. The results are shown in Table 1.
  • ⁇ Production of seed polymer particle A> In a reactor equipped with a stirrer, 95 parts of styrene, 5 parts of divinylbenzene, 1.0 part of sodium dodecylbenzenesulfonate, 100 parts of ion-exchanged water, and 0.5 part of potassium persulfate are placed at 80 ° C. for 8 hours. Polymerized. Thereby, an aqueous dispersion of seed polymer particles A having an average particle diameter of 60 nm was obtained.
  • Example 7 Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 3.4.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the acrylic polymer particle A has a sulfonic acid group-containing monomer unit content of 5.0%, a sulfonic acid group content of 1.95%, and an acrylonitrile monomer unit content of 14.8%.
  • the content ratio of the (meth) acrylic acid ester monomer unit was 80.2%.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 82.9 parts of n-butyl acrylate, 15.2 parts of acrylonitrile, 1.9 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, An aqueous polymer dispersion containing was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having an epoxy acid group is 1.9%
  • the content ratio of the epoxy acid group is 0.58%
  • the content ratio of the acrylonitrile monomer unit is 15.2%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 82.9%.
  • Example 8 Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 0.6.
  • a polymer aqueous dispersion containing an unreacted monomer was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having a sulfonic acid group is 2.2%, the content ratio of the sulfonic acid group is 0.86%, the content ratio of the acrylonitrile monomer unit is 15.2%, The content ratio of the (meth) acrylic acid ester monomer unit was 82.6%.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 80.5 parts of n-butyl acrylate, 14.8 parts of acrylonitrile, 4.7 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, and unreacted monomers are removed.
  • An aqueous polymer dispersion containing was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having an epoxy acid group is 4.7%
  • the content ratio of the epoxy acid group is 1.42%
  • the content ratio of the acrylonitrile monomer unit is 14.8%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 80.5%.
  • Example 9 instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 2.8.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having a sulfonic acid group is 9.8%
  • the content ratio of the sulfonic acid group is 3.82%
  • the content ratio of the acrylonitrile monomer unit is 14.0%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 76.2%.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 80.6 parts of n-butyl acrylate, 14.9 parts of acrylonitrile, 4.5 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, An aqueous polymer dispersion containing was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having an epoxy acid group is 4.5%
  • the content ratio of the epoxy acid group is 1.36%
  • the content ratio of the acrylonitrile monomer unit is 14.9%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 80.6%.
  • Example 10 Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.8.
  • aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • acrylic polymer particle A the content ratio of the monomer unit having a sulfonic acid group is 1.0%, the content ratio of the sulfonic acid group is 0.39%, the content ratio of the acrylonitrile monomer unit is 15.4%, The content ratio of the (meth) acrylic acid ester monomer unit was 83.6%.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 83.9 parts of n-butyl acrylate, 15.4 parts of acrylonitrile, 0.7 part of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, and unreacted monomers are removed.
  • An aqueous polymer dispersion containing was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • acrylic polymer particle B the content ratio of the monomer unit having an epoxy acid group is 0.7%, the content ratio of the epoxy acid group is 0.21%, the content ratio of the acrylonitrile monomer unit is 15.4%, The content ratio of the (meth) acrylic acid ester monomer unit was 83.9%.
  • Example 11 Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.5.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having a sulfonic acid group is 7.7%
  • the content ratio of the sulfonic acid group is 3.00%
  • the content ratio of the acrylonitrile monomer unit is 14.4%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 77.9%.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 78.7 parts of n-butyl acrylate, 14.5 parts of acrylonitrile, 6.8 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, and unreacted monomers are removed.
  • An aqueous polymer dispersion containing was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having an epoxy acid group is 6.8%
  • the content ratio of the epoxy acid group is 2.06%
  • the content ratio of the acrylonitrile monomer unit is 14.5%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 78.7%.
  • Example 12 The same operation as in Example 1 was performed except that the porous film slurry was produced using the following nonconductive particles instead of the nonconductive particles obtained in the steps (1) to (3) of Example 1.
  • the organic separator with a porous membrane and the secondary battery were obtained and evaluated. The results are shown in Table 1.
  • ⁇ Manufacture of seed polymer particles C> In a reactor equipped with a stirrer, 2 parts of the aqueous dispersion of seed polymer particles B obtained in step (2) of Example 1 on a solids basis (ie, based on the weight of seed polymer particles B), sodium dodecylbenzenesulfonate 0.2 parts, 0.5 parts of potassium persulfate and 100 parts of ion-exchanged water were mixed to obtain a mixture, and the temperature was raised to 80 ° C.
  • styrene 97 parts of styrene, 3 parts of methacrylic acid, 4 parts of t-dodecyl mercaptan, 0.5 part of sodium dodecylbenzenesulfonate, and 100 parts of ion-exchanged water were mixed to disperse the monomer mixture.
  • the body was prepared.
  • the monomer mixture dispersion was continuously added to the mixture for 4 hours to polymerize.
  • the temperature of the reaction system during continuous addition of the dispersion of the monomer mixture was maintained at 80 ° C. to carry out the reaction. After completion of the continuous addition, the reaction was further continued at 90 ° C. for 3 hours. Thereby, an aqueous dispersion of seed polymer particles C having an average particle diameter of 400 nm was obtained.
  • Example 13 The same operation as in Example 1 was performed except that the porous film slurry was produced using the following nonconductive particles instead of the nonconductive particles obtained in the steps (1) to (3) of Example 1.
  • the organic separator with a porous membrane and the secondary battery were obtained and evaluated. The results are shown in Table 1.
  • composition of monomers (styrene, methacrylic acid, divinylbenzene, ethylvinylbenzene, and methyl methacrylate) used from formation of seed polymer particles to obtaining nonconductive particles, and heat resistance temperature of nonconductive particles (T10) Value), average circularity and particle size distribution are as shown in Table 1.
  • Example 14 ⁇ Preparation of NMP dispersion of non-conductive particles> After adding 200 parts of N-methyl-2-pyrrolidone (NMP) to 100 parts of an aqueous dispersion of non-conductive particles obtained in step (3) of Example 1 (solid content concentration: 20%) and mixing them well. The water and NMP in the system were distilled off in a 90 ° C. reduced pressure environment to obtain an NMP dispersion of nonconductive particles (solid content concentration 20%).
  • NMP N-methyl-2-pyrrolidone
  • the solid content ratio of the NMP dispersion of non-conductive particles, the NMP dispersion of acrylic polymer particles A, and the NMP dispersion of acrylic polymer particles B obtained in the above steps is 87.0: 6.5: 6.
  • the weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.7.
  • Example 1 a secondary battery was obtained and evaluated in the same manner as in Example 1 except that the above negative electrode with a porous film was used instead of the negative electrode obtained in Step (8) of Example 1. It was. The results are shown in Table 1. In placing the negative electrode with a circular porous film in the outer container, the negative electrode was placed so that the porous film side faced to the circular organic separator side and the copper foil side faced to the upper side.
  • Example 1 except that the porous polymer slurry was produced using the following acrylic polymer particles C instead of the acrylic polymer particles A and B obtained in the steps (4) and (5) of Example 1. The same operation was performed to obtain an organic separator with a porous film and a secondary battery and evaluated. The results are shown in Table 1.
  • Polymerization was performed by heating to obtain an aqueous polymer dispersion containing unreacted monomers. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 ⁇ m acrylic polymer particles C was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. The acrylic polymer particle C had a sulfonic acid group and an epoxy group, and the acrylic polymer particle C had a sulfonic acid group content of 0.78% and an epoxy group content of 0.45%.
  • Comparative Example 2 instead of the acrylic polymer particles B obtained in the step (5) of Example 1, instead of using the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles B were used. Except that the porous membrane slurry was produced, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation was performed. The results are shown in Table 1.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 78.7 parts of n-butyl acrylate, 14.5 parts of acrylonitrile, 6.8 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, and unreacted monomers are removed.
  • An aqueous polymer dispersion containing was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having an epoxy acid group is 6.8%
  • the content ratio of the epoxy acid group is 2.06%
  • the content ratio of the acrylonitrile monomer unit is 14.5%
  • the content ratio of the (meth) acrylic acid ester monomer unit was 78.7%.
  • a polymer aqueous dispersion containing an unreacted monomer was obtained.
  • the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having a sulfonic acid group is 6.8%, the content ratio of the sulfonic acid group is 2.65%, the content ratio of the acrylonitrile monomer unit is 14.5%, The content ratio of the (meth) acrylic acid ester monomer unit was 78.7%.
  • Example 4 The same operation as in Example 1 was performed except that a porous membrane slurry was produced using the following acrylic polymer particles A instead of the acrylic polymer particles A obtained in the step (4) of Example 1. An organic separator with a porous film and a secondary battery were obtained and evaluated. The results are shown in Table 1. In addition, the acrylic polymer particle B used the thing similar to the acrylic polymer particle B obtained at the process (5) of Example 1. FIG.
  • aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 ⁇ m acrylic polymer particles A was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having a sulfonic acid group in the acrylic polymer particle A is 0%, the content ratio of the sulfonic acid group is 0%, the content ratio of the acrylonitrile monomer unit is 15.5%, (meth) acrylic
  • the content rate of the acid ester monomer unit was 84.5%.
  • Example 5 The same operation as in Example 1 was performed except that a porous membrane slurry was produced using the following acrylic polymer particles B instead of the acrylic polymer particles B obtained in the step (5) of Example 1. An organic separator with a porous film and a secondary battery were obtained and evaluated. The results are shown in Table 1. In addition, the acrylic polymer particle A used the thing similar to the acrylic polymer particle A obtained at the process (4) of Example 1. FIG.
  • ⁇ Preparation of acrylic polymer particle B> In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 84.5 parts of n-butyl acrylate, 15.5 parts of acrylonitrile, 0.05 part of t-dodecyl mercaptan as a molecular weight modifier, and potassium persulfate as a polymerization initiator were added in an amount of 0. 3 parts, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier is added, and after sufficiently stirring, polymerization is carried out by heating to 70 ° C., and a polymer aqueous dispersion containing unreacted monomers is prepared. Obtained.
  • aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0.
  • An aqueous dispersion of 18 ⁇ m acrylic polymer particles B was obtained.
  • the polymerization conversion rate determined from the solid content concentration was approximately 99%.
  • the content ratio of the monomer unit having an epoxy acid group in the acrylic polymer particle B is 0%, the content ratio of the epoxy acid group is 0%, the content ratio of the acrylonitrile monomer unit is 15.5%, (meth) acrylic
  • the content rate of the acid ester monomer unit was 84.5%.
  • Secondary battery porous membrane slurry comprising non-conductive particles containing an organic polymer, and a binder, wherein the binder comprises acrylic polymer particles A having sulfonic acid groups and acrylic polymer particles B having epoxy groups
  • the binder comprises acrylic polymer particles A having sulfonic acid groups and acrylic polymer particles B having epoxy groups
  • the secondary battery separator, the secondary battery electrode and the secondary battery having the secondary battery porous film formed using Examples 1 to 14 are excellent in the balance of the uniformity, reliability and cycle characteristics of the porous film.

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Abstract

[Problem] To provide a high-strength, highly uniform secondary-battery porous membrane that is capable of improving the cycle characteristics of a resulting secondary battery and is manufactured using a secondary-battery porous-membrane slurry that exhibits excellent coating performance and contains highly-dispersed nonconductive particles. Also, to provide a secondary-battery electrode and secondary-battery separator having good shutdown functionality. [Solution] This secondary-battery porous-membrane slurry is characterized by containing organic-polymer-containing nonconductive particles, a binder, and a solvent, and is further characterized in that said binder contains particles (A) of an acrylic polymer that has a sulfonic acid group and particles (B) of an acrylic polymer that has an epoxy group.

Description

二次電池多孔膜スラリー、二次電池多孔膜、二次電池電極、二次電池セパレーター、二次電池、及び二次電池多孔膜の製造方法Secondary battery porous membrane slurry, secondary battery porous membrane, secondary battery electrode, secondary battery separator, secondary battery, and method for producing secondary battery porous membrane
　本発明は二次電池多孔膜スラリーに関し、さらに詳しくはリチウムイオン二次電池の電極またはセパレーターの表面に形成され、信頼性が高く、電池のサイクル特性の改善に寄与しうる二次電池多孔膜を製造するための二次電池多孔膜スラリーに関する。また本発明は、かかる二次電池多孔膜を備えた二次電池電極、二次電池セパレーター及び二次電池に関する。 The present invention relates to a secondary battery porous membrane slurry, and more specifically, a secondary battery porous membrane formed on the surface of an electrode or separator of a lithium ion secondary battery, which has high reliability and can contribute to improvement of battery cycle characteristics. The present invention relates to a secondary battery porous membrane slurry for manufacturing. The present invention also relates to a secondary battery electrode, a secondary battery separator and a secondary battery provided with such a secondary battery porous membrane.
　実用化されている電池の中でも、リチウムイオン二次電池は最も高いエネルギー密度を示し、特に小型エレクトロニクス用に多く使用されている。また、小型用途に加えて自動車向けへの展開も期待されている。その中で、リチウムイオン二次電池の長寿命化と、安全性のさらなる向上が要望されている。 Among the batteries in practical use, lithium ion secondary batteries exhibit the highest energy density, and are often used especially for small electronics. In addition to small-sized applications, development for automobiles is also expected. Among them, there is a demand for extending the life of lithium ion secondary batteries and further improving safety.
　リチウムイオン二次電池には、一般に、正極と負極との間の短絡を防ぐ為に、ポリエチレンやポリプロピレン等のポリオレフィン系有機セパレーターが用いられている。ポリオレフィン系有機セパレーターは２００℃以下で溶融する物性を有している為、内部及びまたは外部の刺激により電池が高温になる場合には、有機セパレーターの収縮や溶融などが起こり、有機セパレーターの体積が変化する。その結果、正極及び負極の短絡、電気エネルギーの放出などにより爆発などが起こる恐れがある。 In general, a lithium-ion secondary battery uses a polyolefin-based organic separator such as polyethylene or polypropylene in order to prevent a short circuit between the positive electrode and the negative electrode. Since the polyolefin-based organic separator has a physical property of melting at 200 ° C. or lower, when the battery becomes hot due to internal or external stimulation, the organic separator shrinks or melts, and the volume of the organic separator is increased. Change. As a result, an explosion or the like may occur due to a short circuit between the positive electrode and the negative electrode, discharge of electric energy, or the like.
　このような、ポリオレフィン系有機セパレーターを用いることに起因した問題を解決するため、ポリオレフィン系有機セパレーター上又は電極（正極や負極）上に、無機粒子などの非導電性粒子を含有する層（多孔膜）を積層することが提案されている。更に、電池の異常反応による熱暴走を防ぐために、熱で溶融するポリマー粒子や、熱で電解液への膨潤度が上昇するポリマー粒子を含む多孔膜が提案されている。短絡などにより二次電池の温度が異常上昇した場合、多孔膜中の微細な空孔を、該ポリマー粒子が溶融又は膨潤することにより閉塞し、これにより電極間のイオン通過が阻止されるので、電流を遮断し、それ以上の温度上昇を抑制する機能（シャットダウン機能）を有すると考えられている。 In order to solve the problems caused by using such a polyolefin-based organic separator, a layer (porous film) containing non-conductive particles such as inorganic particles on the polyolefin-based organic separator or on the electrode (positive electrode or negative electrode) ) Is proposed. Furthermore, in order to prevent thermal runaway due to an abnormal reaction of the battery, a porous film including polymer particles that are melted by heat and polymer particles that increase the degree of swelling into an electrolyte solution by heat has been proposed. When the temperature of the secondary battery rises abnormally due to a short circuit or the like, fine pores in the porous film are blocked by melting or swelling of the polymer particles, thereby preventing ions from passing between the electrodes. It is considered to have a function (shutdown function) that cuts off current and suppresses further temperature rise.
　例えば、特許文献１には、安全性向上のため、耐熱性樹脂微粒子とシャットダウン機能を持つ有機微粒子とを含む多孔膜が記載されている。また、多孔膜用バインダーとしてエチレン－酢酸ビニル重合体を用いることが記載されている。 For example, Patent Document 1 describes a porous film containing heat-resistant resin fine particles and organic fine particles having a shutdown function for improving safety. Further, it is described that an ethylene-vinyl acetate polymer is used as a binder for a porous film.
　特許文献２には、スルホン酸等の親水性基を有する水分散性アクリル重合体粒子をバインダーとして用いることで多孔膜からの無機フィラーの粉落ちを改善する方法が記載されている。また、水分散性アクリル重合体粒子中に、更に架橋性基を有することで、強靭で柔軟な多孔膜を有することができることが記載されている。 Patent Document 2 describes a method for improving powder-off of inorganic filler from a porous film by using water-dispersible acrylic polymer particles having a hydrophilic group such as sulfonic acid as a binder. Further, it is described that a water-dispersible acrylic polymer particle can have a tough and flexible porous film by further having a crosslinkable group.
特開２００６－１３９９７８号公報JP 2006-139978 A 国際特許公開ＷＯ２００９／１２３１６８号International Patent Publication WO2009 / 123168
　しかしながら、本発明者の検討によれば、特許文献１に記載の多孔膜は、エチレン－酢酸ビニル重合体をバインダーとして用いているために、該多孔膜を形成するためのスラリーにおける耐熱性樹脂微粒子と有機微粒子の分散性が十分でなく、多孔膜の均一性に劣る。その結果、多孔膜に十分な強度とシャットダウン機能を持たせることができない場合があった。また、特許文献２に記載の多孔膜は、多孔膜スラリー中での無機フィラーの分散性に優れるが、バインダーとしてのアクリル重合体粒子中に親水性基と架橋性基とを含有させた場合、互いに反応性を有する官能基があるため、スラリー製造工程で架橋反応を起こす傾向があることが分かった。そのため、スラリーの塗工性が経時的に不安定となり、結果として、多孔膜の均一性及び強度が不十分となる場合があった。 However, according to the study of the present inventor, since the porous film described in Patent Document 1 uses an ethylene-vinyl acetate polymer as a binder, the heat-resistant resin fine particles in the slurry for forming the porous film And the dispersibility of the organic fine particles is not sufficient, and the uniformity of the porous film is poor. As a result, the porous membrane may not have sufficient strength and a shutdown function. Moreover, the porous film described in Patent Document 2 is excellent in dispersibility of the inorganic filler in the porous film slurry. However, when a hydrophilic group and a crosslinkable group are contained in the acrylic polymer particles as a binder, It was found that there is a tendency to cause a crosslinking reaction in the slurry production process because there are functional groups having reactivity with each other. Therefore, the coating property of the slurry becomes unstable over time, and as a result, the uniformity and strength of the porous film may be insufficient.
　したがって、本発明は、塗工性及び非導電性粒子の分散性に優れた二次電池多孔膜スラリーを用いて製造され、得られる二次電池のサイクル特性を向上させることができ、均一性及び強度の高い二次電池多孔膜を提供することを目的としている。また、シャットダウン機能の良好な二次電池電極及び二次電池セパレーターを提供することを目的としている。 Therefore, the present invention can be produced using a secondary battery porous membrane slurry excellent in coatability and dispersibility of non-conductive particles, and can improve the cycle characteristics of the obtained secondary battery. It aims at providing a secondary battery porous membrane with high intensity. Moreover, it aims at providing the secondary battery electrode and secondary battery separator with a favorable shutdown function.
　そこで、本発明者が検討した結果、スルホン酸基とエポキシ基とをそれぞれ別のアクリル重合体粒子中に導入し、それらをブレンドしたものをバインダーとして用いることで、多孔膜の均一性及び強度を向上させることができることを見出した。つまり、特定のバインダーを用いることで、スラリー製造工程における架橋反応を抑制し、スラリーの増粘などを低減できる。そのため、多孔膜スラリー中における非導電性粒子の分散性と多孔膜スラリーの塗工性を改善でき、均一性及び強度の高い多孔膜を得ることができる。また、本発明者は、多孔膜スラリー中における非導電性粒子の分散性と多孔膜スラリーの塗工性が改善されることで、多孔膜の生産性に加え、該多孔膜を用いた二次電池のサイクル特性も向上することを見出した。 Therefore, as a result of the study by the present inventors, the uniformity and strength of the porous film can be improved by introducing a sulfonic acid group and an epoxy group into different acrylic polymer particles and using them as a binder. It was found that it can be improved. That is, by using a specific binder, the crosslinking reaction in the slurry production process can be suppressed, and the viscosity of the slurry can be reduced. Therefore, the dispersibility of non-conductive particles in the porous membrane slurry and the coating property of the porous membrane slurry can be improved, and a porous membrane having high uniformity and strength can be obtained. Further, the present inventor has improved the dispersibility of non-conductive particles in the porous membrane slurry and the coating property of the porous membrane slurry, so that in addition to the productivity of the porous membrane, the secondary using the porous membrane It has been found that the cycle characteristics of the battery are also improved.
　このような課題の解決を目的とした本発明の要旨は以下のとおりである。
（１）有機高分子を含む非導電性粒子、バインダー及び溶媒を含んでなり、
　該バインダーが、スルホン酸基を有するアクリル重合体粒子Ａ、及びエポキシ基を有するアクリル重合体粒子Ｂを含む二次電池多孔膜スラリー。 The gist of the present invention aimed at solving such problems is as follows.
(1) comprising non-conductive particles containing an organic polymer, a binder and a solvent;
The secondary battery porous membrane slurry in which the binder contains acrylic polymer particles A having sulfonic acid groups and acrylic polymer particles B having epoxy groups.
（２）全固形分１００質量％当たりの前記非導電性粒子の含有割合が７０～９７質量％、前記バインダーの含有割合が０．５～２０質量％である（１）に記載の二次電池多孔膜スラリー。 (2) The secondary battery according to (1), wherein the content of the nonconductive particles per 100% by mass of the total solid is 70 to 97% by mass and the content of the binder is 0.5 to 20% by mass. Porous membrane slurry.
（３）前記アクリル重合体粒子Ａ及び前記アクリル重合体粒子Ｂが、
　（メタ）アクリロニトリル単量体単位、及び（メタ）アクリル酸エステル単量体単位を含んでなる（１）または（２）に記載の二次電池多孔膜スラリー。 (3) The acrylic polymer particles A and the acrylic polymer particles B are
The secondary battery porous membrane slurry according to (1) or (2), comprising a (meth) acrylonitrile monomer unit and a (meth) acrylate monomer unit.
（４）前記アクリル重合体粒子Ａ及び前記アクリル重合体粒子Ｂにおける、
　重合体粒子中の（メタ）アクリロニトリル単量体単位の含有割合が２．５～４０質量％であり、
　重合体粒子中の（メタ）アクリル酸エステル単量体単位の含有割合が６０～９７．５質量％である（３）に記載の二次電池多孔膜スラリー。 (4) In the acrylic polymer particles A and the acrylic polymer particles B,
The content ratio of the (meth) acrylonitrile monomer unit in the polymer particles is 2.5 to 40% by mass,
The secondary battery porous membrane slurry according to (3), wherein the content ratio of the (meth) acrylic acid ester monomer unit in the polymer particles is 60 to 97.5% by mass.
（５）前記アクリル重合体粒子Ｂに対する前記アクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）が０．３～３である（１）～（４）のいずれかに記載の二次電池多孔膜スラリー。 (5) Any of (1) to (4), wherein a weight ratio of the acrylic polymer particles A to the acrylic polymer particles B (acrylic polymer particles A / acrylic polymer particles B) is 0.3 to 3. The secondary battery porous membrane slurry according to 1.
（６）前記アクリル重合体粒子Ａにおけるスルホン酸基の含有割合が０．０４～５．８質量％、前記アクリル重合体粒子Ｂにおけるエポキシ基の含有割合が０．０３～３．０質量％である、（１）～（５）のいずれかに記載の二次電池多孔膜スラリー。 (6) The content ratio of sulfonic acid groups in the acrylic polymer particles A is 0.04 to 5.8 mass%, and the content ratio of epoxy groups in the acrylic polymer particles B is 0.03 to 3.0 mass%. The secondary battery porous membrane slurry according to any one of (1) to (5).
（７）前記バインダーにおける、前記アクリル重合体粒子Ｂにおけるエポキシ基に対する前記アクリル重合体粒子Ａにおけるスルホン酸基の重量比（スルホン酸基／エポキシ基）が０．２～３である（１）～（６）のいずれかに記載の二次電池多孔膜スラリー。 (7) In the binder, the weight ratio of the sulfonic acid group in the acrylic polymer particle A to the epoxy group in the acrylic polymer particle B (sulfonic acid group / epoxy group) is 0.2 to 3. (6) The secondary battery porous membrane slurry according to any one of (6).
（８）熱天秤により窒素雰囲気下で昇温速度１０℃／分で加熱したときの前記非導電性粒子の減量割合が１０質量％に達する温度が２５０℃以上であり、
　該非導電性粒子の平均粒子径が０．１～２．０μｍであり、
　該非導電性粒子の平均円形度が０．９００～０．９９５である（１）～（７）のいずれかに記載の二次電池多孔膜スラリー。 (8) The temperature at which the weight loss ratio of the non-conductive particles reaches 10% by mass when heated at a heating rate of 10 ° C./min in a nitrogen atmosphere by a thermobalance is 250 ° C. or more,
The non-conductive particles have an average particle size of 0.1 to 2.0 μm;
The secondary battery porous membrane slurry according to any one of (1) to (7), wherein the non-conductive particles have an average circularity of 0.900 to 0.995.
（９）上記（１）～（８）のいずれかに記載の二次電池多孔膜スラリーを、膜状に形成、乾燥してなる二次電池多孔膜。 (9) A secondary battery porous membrane formed by forming the secondary battery porous membrane slurry according to any one of (1) to (8) above into a film and drying it.
（１０）集電体、
　該集電体に付着してなる、電極活物質及び電極用結着剤を含んでなる電極活物質層、及び、
　該電極活物質層の表面に積層された、（９）に記載の二次電池多孔膜、を含んでなる、二次電池電極。 (10) current collector,
An electrode active material layer comprising an electrode active material and an electrode binder, which is attached to the current collector; and
A secondary battery electrode comprising the secondary battery porous film according to (9), which is laminated on the surface of the electrode active material layer.
（１１）有機セパレーター、
　該有機セパレーターに積層された、（９）に記載の二次電池多孔膜、を含んでなる、二次電池セパレーター。 (11) Organic separator,
A secondary battery separator comprising the secondary battery porous film according to (9), which is laminated on the organic separator.
（１２）正極、負極、有機セパレーター及び電解液を含む二次電池であって、前記正極、負極及び有機セパレーターのいずれかに、（９）に記載の二次電池多孔膜が積層されてなる二次電池。 (12) A secondary battery including a positive electrode, a negative electrode, an organic separator, and an electrolyte solution, wherein the secondary battery porous film according to (9) is laminated on any of the positive electrode, the negative electrode, and the organic separator. Next battery.
（１３）上記（１）～（８）のいずれかに記載の二次電池多孔膜スラリーを基材に塗布し、次いで乾燥する工程を含む二次電池多孔膜の製造方法。 (13) A method for producing a secondary battery porous membrane comprising a step of applying the secondary battery porous membrane slurry according to any one of (1) to (8) above to a substrate and then drying.
　本発明によれば、非導電性粒子と特性組成のバインダーを含むことで、均一性及び強度に優れ、二次電池のサイクル特性に寄与しうる二次電池多孔膜を製造するための二次電池多孔膜スラリーが提供される。また、該多孔膜スラリーは分散性と塗工性に優れる。さらにまた、該多孔膜スラリーを用いて製造される二次電池多孔膜を、電極や有機セパレーターの表面に積層することで、非導電性粒子や電極活物質の脱離防止（粉落ち性）や、シャットダウン機能（信頼性）に優れる。 According to the present invention, a secondary battery for producing a secondary battery porous film that is excellent in uniformity and strength and can contribute to cycle characteristics of a secondary battery by including non-conductive particles and a binder having a characteristic composition. A porous membrane slurry is provided. The porous film slurry is excellent in dispersibility and coatability. Furthermore, the secondary battery porous membrane produced using the porous membrane slurry is laminated on the surface of the electrode or organic separator, thereby preventing non-conductive particles and electrode active material from detaching (powder-off). Excellent shutdown function (reliability).
　以下、本発明の（１）二次電池多孔膜スラリー、（２）二次電池多孔膜、（３）二次電池電極、（４）二次電池セパレーター、及び（５）二次電池について順次説明する。 Hereinafter, (1) secondary battery porous membrane slurry, (2) secondary battery porous membrane, (3) secondary battery electrode, (4) secondary battery separator, and (5) secondary battery of the present invention will be described in order. To do.
（１）二次電池多孔膜スラリー
　本発明の二次電池多孔膜スラリー（以下、「多孔膜スラリー」と表すことがある。）は、後述する二次電池多孔膜を形成するためのスラリーである。多孔膜スラリーは、非導電性粒子と特性組成のバインダーを含み、固形分として該非導電性粒子、該バインダー及び任意の成分を、後述する溶媒に均一に分散したものである。 (1) Secondary Battery Porous Membrane Slurry The secondary battery porous membrane slurry of the present invention (hereinafter sometimes referred to as “porous membrane slurry”) is a slurry for forming a secondary battery porous membrane described later. . The porous film slurry contains non-conductive particles and a binder having a characteristic composition, and the non-conductive particles, the binder and optional components are uniformly dispersed in a solvent described later as a solid content.
（非導電性粒子）
　本発明に用いる非導電性粒子は、有機高分子を含む。本発明においては、有機高分子を含む非導電性粒子を用いることで、二次電池の性能に悪影響を及ぼす金属のコンタミネーション（以下、「金属異物」と表すことがある。）を少なくすることができると共に、二次電池多孔膜スラリーの製造コストを抑えることができる。 (Non-conductive particles)
The nonconductive particles used in the present invention include an organic polymer. In the present invention, by using non-conductive particles containing an organic polymer, metal contamination (hereinafter sometimes referred to as “metal foreign matter”) that adversely affects the performance of the secondary battery is reduced. In addition, the production cost of the secondary battery porous membrane slurry can be reduced.
　非導電性粒子は、ジビニルベンゼン単量体単位を含むことが好ましい。非導電性粒子における単量体合計重量中のジビニルベンゼン単量体単位の含有割合は、好ましくは２０～８０質量％、より好ましくは２５～７０質量％、特に好ましくは３０～６０質量％である。ジビニルベンゼン単量体単位の含有割合を上記範囲とすることで、非導電性粒子の架橋密度が高くなるため非導電性粒子の耐熱性が向上し、得られる二次電池多孔膜の信頼性も向上する。 The non-conductive particles preferably contain divinylbenzene monomer units. The content ratio of the divinylbenzene monomer unit in the total monomer weight in the non-conductive particles is preferably 20 to 80% by mass, more preferably 25 to 70% by mass, and particularly preferably 30 to 60% by mass. . By setting the content ratio of the divinylbenzene monomer unit within the above range, the crosslink density of the nonconductive particles is increased, so that the heat resistance of the nonconductive particles is improved, and the reliability of the obtained secondary battery porous film is also improved. improves.
　非導電性粒子は、更にエチルビニルベンゼン単量体単位を含むことが好ましい。非導電性粒子における単量体合計重量中のエチルビニルベンゼン単量体単位の含有割合は、好ましくは３．２～４８質量％、より好ましくは１０～４０質量％である。エチルビニルベンゼン単量体単位の含有割合を上記範囲とすることで、後述するバインダーとの結着性が良好になると共に、得られる二次電池多孔膜の柔軟性が良好になる。また、該二次電池多孔膜を電極に積層して二次電池電極を作製した場合において、電極活物質の脱離（粉落ち）を防止できる。その結果、該二次電池多孔膜を用いた二次電池は優れたサイクル特性を示す。 The non-conductive particles preferably further contain an ethyl vinyl benzene monomer unit. The content ratio of the ethyl vinylbenzene monomer unit in the total monomer weight in the non-conductive particles is preferably 3.2 to 48% by mass, more preferably 10 to 40% by mass. By making the content rate of an ethyl vinylbenzene monomer unit into the said range, while the binding property with the binder mentioned later becomes favorable, the softness | flexibility of the secondary battery porous film obtained becomes favorable. Further, when the secondary battery porous film is laminated on the electrode to produce a secondary battery electrode, it is possible to prevent the electrode active material from being detached (powder falling). As a result, the secondary battery using the secondary battery porous film exhibits excellent cycle characteristics.
　非導電性粒子に含まれるジビニルベンゼン単量体単位とエチルビニルベンゼン単量体単位の含有量比（ジビニルベンゼン／エチルビニルベンゼン）は、好ましくは１．０～５．２５、より好ましくは１．２５～５．００、特に好ましくは１．２５～４．７５である。非導電性粒子に含まれるジビニルベンゼン単量体単位とエチルビニルベンゼン単量体単位の含有量比を上記範囲とすることで、非導電性粒子の架橋密度が高くなるため非導電性粒子の耐熱性が向上する。その結果、得られる二次電池多孔膜の柔軟性及び強度が向上する。また、二次電池電極を作製した場合において、電極活物質の脱離（粉落ち）を防止できるため、該二次電池多孔膜を用いた二次電池は優れたサイクル特性を示す。 The content ratio (divinylbenzene / ethylvinylbenzene) of the divinylbenzene monomer unit and the ethylvinylbenzene monomer unit contained in the nonconductive particles is preferably 1.0 to 5.25, more preferably 1. It is 25 to 5.00, particularly preferably 1.25 to 4.75. By setting the content ratio of the divinylbenzene monomer unit and the ethylvinylbenzene monomer unit contained in the nonconductive particles within the above range, the crosslink density of the nonconductive particles is increased, so that the heat resistance of the nonconductive particles is increased. Improves. As a result, the flexibility and strength of the obtained secondary battery porous membrane are improved. In addition, when a secondary battery electrode is produced, the electrode active material can be prevented from being detached (powder falling), and therefore a secondary battery using the secondary battery porous film exhibits excellent cycle characteristics.
　非導電性粒子は、上記２種の単量体単位に加えて、極性基含有モノマーを含むことが好ましい。 The non-conductive particles preferably contain a polar group-containing monomer in addition to the two types of monomer units.
　極性基含有モノマーとは、分子構造中に極性基を含有し、且つ、ジビニルベンゼン及びエチルビニルベンゼンと共重合しうる単量体である。極性基とは、水中で解離しうる官能基や分極を有する官能基のことをいい、具体的には、カルボキシル基、スルホン酸基、水酸基、アミド基、カチオン性基、シアノ基、エポキシ基などが挙げられる。 The polar group-containing monomer is a monomer that contains a polar group in the molecular structure and can be copolymerized with divinylbenzene and ethylvinylbenzene. A polar group refers to a functional group that can dissociate in water or a functional group having polarization. Specifically, a carboxyl group, a sulfonic acid group, a hydroxyl group, an amide group, a cationic group, a cyano group, an epoxy group, and the like. Is mentioned.
　カルボキシル基含有モノマーとしては、モノカルボン酸、ジカルボン酸、ジカルボン酸の無水物、及びこれらの誘導体などが挙げられる。
　モノカルボン酸としては、アクリル酸、メタクリル酸、クロトン酸、２－エチルアクリル酸、イソクロトン酸、α－アセトキシアクリル酸、β－ｔｒａｎｓ－アリールオキシアクリル酸、α－クロロ－β－Ｅ－メトキシアクリル酸、β－ジアミノアクリル酸などが挙げられる。
　ジカルボン酸としては、マレイン酸、フマル酸、イタコン酸、メチルマレイン酸、ジメチルマレイン酸、フェニルマレイン酸、クロロマレイン酸、ジクロロマレイン酸、及びフルオロマレイン酸などが挙げられる。
　ジカルボン酸の無水物としては、無水マレイン酸、アクリル酸無水物、メチル無水マレイン酸、ジメチル無水マレイン酸などが挙げられる。
　ジカルボン酸誘導体としては、マレイン酸メチルアリル、マレイン酸ジフェニル、マレイン酸ノニル、マレイン酸デシル、マレイン酸ドデシル、マレイン酸オクタデシル、及びマレイン酸フルオロアルキルなどのマレイン酸エステルが挙げられる。 Examples of the carboxyl group-containing monomer include monocarboxylic acids, dicarboxylic acids, dicarboxylic acid anhydrides, and derivatives thereof.
Monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, isocrotonic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid , Β-diaminoacrylic acid and the like.
Examples of the dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, and fluoromaleic acid.
Examples of the dicarboxylic acid anhydride include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride.
Dicarboxylic acid derivatives include maleic esters such as methyl allyl maleate, diphenyl maleate, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, and fluoroalkyl maleate.
　スルホン酸基含有モノマーとしては、ビニルスルホン酸、メチルビニルスルホン酸、（メタ）アリルスルホン酸、スチレンスルホン酸、（メタ）アクリル酸－２－スルホン酸エチル、２－アクリルアミド－２－メチルプロパンスルホン酸、３－アリロキシ－２－ヒドロキシプロパンスルホン酸などが挙げられる。 Examples of the sulfonic acid group-containing monomer include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylic acid-2-ethyl sulfonate, 2-acrylamido-2-methylpropane sulfonic acid. And 3-allyloxy-2-hydroxypropanesulfonic acid.
　水酸基含有モノマーとしては、（メタ）アリルアルコール、３－ブテン－１－オール、５－ヘキセン－１－オールなどのエチレン性不飽和アルコール；アクリル酸－２－ヒドロキシエチル、アクリル酸－２－ヒドロキシプロピル、メタクリル酸－２－ヒドロキシエチル、メタクリル酸－２－ヒドロキシプロピル、マレイン酸ジ－２－ヒドロキシエチル、マレイン酸ジ－４－ヒドロキシブチル、イタコン酸ジ－２－ヒドロキシプロピルなどのエチレン性不飽和カルボン酸のアルカノールエステル類；一般式ＣＨ２＝ＣＲ１－ＣＯＯ－（ＣｎＨ２ｎＯ）ｍ－Ｈ（ｍは２ないし９の整数、ｎは２ないし４の整数、Ｒ１は水素又はメチル基を表す）で表されるポリアルキレングリコールと（メタ）アクリル酸とのエステル類；２－ヒドロキシエチル－２’－（メタ）アクリロイルオキシフタレート、２－ヒドロキシエチル－２’－（メタ）アクリロイルオキシサクシネートなどのジカルボン酸のジヒドロキシエステルのモノ（メタ）アクリル酸エステル類；２－ヒドロキシエチルビニルエーテル、２－ヒドロキシプロピルビニルエーテルなどのビニルエーテル類；（メタ）アリル－２－ヒドロキシエチルエーテル、（メタ）アリル－２－ヒドロキシプロピルエーテル、（メタ）アリル－３－ヒドロキシプロピルエーテル、（メタ）アリル－２－ヒドロキシブチルエーテル、（メタ）アリル－３－ヒドロキシブチルエーテル、（メタ）アリル－４－ヒドロキシブチルエーテル、（メタ）アリル－６－ヒドロキシヘキシルエーテルなどのアルキレングリコールのモノ（メタ）アリルエーテル類；ジエチレングリコールモノ（メタ）アリルエーテル、ジプロピレングリコールモノ（メタ）アリルエーテルなどのポリオキシアルキレングリコール（メタ）モノアリルエーテル類；グリセリンモノ（メタ）アリルエーテル、（メタ）アリル－２－クロロ－３－ヒドロキシプロピルエーテル、（メタ）アリル－２－ヒドロキシ－３－クロロプロピルエーテルなどの、（ポリ）アルキレングリコールのハロゲン及びヒドロキシ置換体のモノ（メタ）アリルエーテル；オイゲノール、イソオイゲノールなどの多価フェノールのモノ（メタ）アリルエーテル及びそのハロゲン置換体；（メタ）アリル－２－ヒドロキシエチルチオエーテル、（メタ）アリル－２－ヒドロキシプロピルチオエーテルなどのアルキレングリコールの（メタ）アリルチオエーテル類；などが挙げられる。 Examples of the hydroxyl group-containing monomer include ethylenically unsaturated alcohols such as (meth) allyl alcohol, 3-buten-1-ol, 5-hexen-1-ol; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate Ethylenically unsaturated carboxylic acids such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, di-2-hydroxyethyl maleate, di-4-hydroxybutyl maleate and di-2-hydroxypropyl itaconate Alkanol esters of acids; general formula CH 2 ═CR 1 —COO— (C n H 2n O) m —H (m is an integer from 2 to 9, n is an integer from 2 to 4, R 1 is a hydrogen or methyl group 2-hydroxy ester of polyalkylene glycol and (meth) acrylic acid represented by Mono (meth) acrylic esters of dihydroxy esters of dicarboxylic acids such as til-2 ′-(meth) acryloyloxyphthalate, 2-hydroxyethyl-2 ′-(meth) acryloyloxysuccinate; 2-hydroxyethyl vinyl ether; Vinyl ethers such as 2-hydroxypropyl vinyl ether; (meth) allyl-2-hydroxyethyl ether, (meth) allyl-2-hydroxypropyl ether, (meth) allyl-3-hydroxypropyl ether, (meth) allyl-2- Mono (meth) allyl ethers of alkylene glycols such as hydroxybutyl ether, (meth) allyl-3-hydroxybutyl ether, (meth) allyl-4-hydroxybutyl ether, (meth) allyl-6-hydroxyhexyl ether Polyoxyalkylene glycol (meth) monoallyl ethers such as diethylene glycol mono (meth) allyl ether and dipropylene glycol mono (meth) allyl ether; glycerin mono (meth) allyl ether, (meth) allyl-2-chloro-3 -Mono (meth) allyl ethers of halogen and hydroxy-substituted products of (poly) alkylene glycol, such as hydroxypropyl ether, (meth) allyl-2-hydroxy-3-chloropropyl ether; polyphenols such as eugenol, isoeugenol (Meth) allylthio of alkylene glycol such as (meth) allyl-2-hydroxyethylthioether, (meth) allyl-2-hydroxypropylthioether, and the like Ether compounds; and the like.
　アミド基含有モノマーとしては、アクリルアミド、メタクリルアミド、Ｎ－メチロールアクリルアミド、Ｎ－メチロールメタクリルアミドなどが挙げられる。 Examples of the amide group-containing monomer include acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide and the like.
　カチオン性基含有モノマーとしては、ジメチルアミノエチル（メタ）アクリレート、ジメチルアミノプロピル（メタ）アクリレートなどが挙げられる。 Examples of the cationic group-containing monomer include dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate.
　シアノ基含有モノマーとしては、アクリロニトリル、メタクリロニトリルなどのシアン化ビニル化合物が挙げられる。 Examples of the cyano group-containing monomer include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile.
　エポキシ基含有モノマーとしては、グリシジルアクリレート、グリシジルメタクリレートなどが挙げられる。 Examples of the epoxy group-containing monomer include glycidyl acrylate and glycidyl methacrylate.
　カルボキシル基含有モノマー、スルホン酸基含有モノマー、水酸基含有モノマー、アミド基含有モノマー、カチオン性基含有モノマー、及びシアノ基含有モノマーの塩としては、上に列挙した単量体と、それらと組み合わせうる適切なイオンとにより構成される、ナトリウム塩、カリウム塩等のアルカリ金属塩、カルシウム塩、マグネシウム塩等のアルカリ土類金属塩、アンモニウム塩、モノエタノールアミン塩、トリエタノールアミン塩等の有機アミン塩などを挙げることができる。 As salts of carboxyl group-containing monomers, sulfonic acid group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, cationic group-containing monomers, and cyano group-containing monomers, the monomers listed above and appropriate combinations thereof can be used. Composed of various ions, alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt, organic amine salts such as ammonium salt, monoethanolamine salt and triethanolamine salt Can be mentioned.
　極性基含有モノマーとしては、カルボキシル基含有モノマー、アミド基含有モノマーが好ましく、アクリル酸、メタクリル酸、イタコン酸、アクリルアミドが特に好ましい。 As the polar group-containing monomer, a carboxyl group-containing monomer and an amide group-containing monomer are preferable, and acrylic acid, methacrylic acid, itaconic acid, and acrylamide are particularly preferable.
　非導電性粒子における単量体合計重量中の極性基含有モノマーの含有割合は、好ましくは０．０５～４質量％、より好ましくは０．１～３質量％、特に好ましくは０．２～２質量％である。非導電性粒子における単量体合計重量中の極性基含有モノマーの含有割合が上記範囲であると、分散性に優れ、かつ非導電性粒子表面の含水量が少ない為に、優れたサイクル特性を示す。 The content ratio of the polar group-containing monomer in the total monomer weight in the non-conductive particles is preferably 0.05 to 4% by mass, more preferably 0.1 to 3% by mass, and particularly preferably 0.2 to 2%. % By mass. When the content ratio of the polar group-containing monomer in the total monomer weight in the non-conductive particles is in the above range, excellent dispersibility and low moisture content on the surface of the non-conductive particles have excellent cycle characteristics. Show.
　非導電性粒子は、上記３種の単量体単位に加えて、任意の単量体単位を含んでもよい。任意の単量体としては、多価（メタ）アクリレート化合物、芳香族モノビニル化合物、（メタ）アクリル酸エステルモノマー、共役ジエンモノマー、ビニルエステル化合物、α－オレフィン化合物が挙げられる。これらの単量体は、非導電性粒子中に２種以上含まれていてもよい。 The non-conductive particles may contain an arbitrary monomer unit in addition to the above three types of monomer units. Examples of the optional monomer include polyvalent (meth) acrylate compounds, aromatic monovinyl compounds, (meth) acrylic acid ester monomers, conjugated diene monomers, vinyl ester compounds, and α-olefin compounds. Two or more of these monomers may be contained in the nonconductive particles.
　多価（メタ）アクリレート化合物としては、ポリエチレングリコールジアクリレート、１，３－ブチレングリコールジアクリレート、１，６－ヘキサングリコールジアクリレート、ネオペンチルグリコールジアクリレート、ポリプロピレングリコールジアクリレート、２，２’－ビス（４－アクリロキシプロピロキシフェニル）プロパン、２，２’－ビス（４－アクリロキシジエトキシフェニル）プロパンなどのジアクリレート化合物；トリメチロールプロパントリアクリレート、トリメチロールエタントリアクリレート、テトラメチロールメタントリアクリレートなどのトリアクリレート化合物；テトラメチロールメタンテトラアクリレートなどのテトラアクリレート化合物；エチレングリコールジメタクリレート、ジエチレングリコールジメタクリレート、トリエチレングリコールジメタクリレート、ポリエチレングリコールジメタクリレート、１，３－ブチレングリコールジメタクリレート、１，４－ブチレングリコールジメタクリレート、１，６－ヘキサングリコールジメタクリレート、ネオペンチルグリコールジメタクリレート、ジプロピレングリコールジメタクリレート、ポリプロピレングリコールジメタクリレート、２，２’－ビス（４－メタクリロキシジエトキシフェニル）プロパンなどのジメタクリレート化合物；トリメチロールプロパントリメタクリレート、トリメチロールエタントリメタクリレートなどのトリメタクリレート化合物などが挙げられる。これらの中でも、エチレングリコールジメタクリレートまたはトリメチロールプロパントリメタクリレートを用いることが好ましい。 Examples of the polyvalent (meth) acrylate compound include polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol diacrylate, neopentyl glycol diacrylate, polypropylene glycol diacrylate, and 2,2′-bis. Diacrylate compounds such as (4-acryloxypropyroxyphenyl) propane and 2,2′-bis (4-acryloxydiethoxyphenyl) propane; trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate Triacrylate compounds such as; tetraacrylate compounds such as tetramethylol methane tetraacrylate; ethylene glycol dimethacrylate, diethylene glycol Dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol Dimethacrylate compounds such as dimethacrylate, polypropylene glycol dimethacrylate, and 2,2′-bis (4-methacryloxydiethoxyphenyl) propane; and trimethacrylate compounds such as trimethylolpropane trimethacrylate and trimethylolethane trimethacrylate . Among these, it is preferable to use ethylene glycol dimethacrylate or trimethylolpropane trimethacrylate.
　芳香族モノビニル化合物としては、スチレン、α－メチルスチレン、フルオロスチレン、ビニルピリジンなどが挙げられる。 Examples of the aromatic monovinyl compound include styrene, α-methylstyrene, fluorostyrene, vinyl pyridine and the like.
　アクリル酸エステルモノマーとしては、ブチルアクリレート、２－エチルヘキシルエチルアクリレート、Ｎ，Ｎ’－ジメチルアミノエチルアクリレートなどが挙げられる。 Examples of the acrylate monomer include butyl acrylate, 2-ethylhexyl ethyl acrylate, N, N′-dimethylaminoethyl acrylate, and the like.
　メタクリル酸エステルモノマーとしては、ブチルメタクリレート、２－エチルヘキシルメタクリレート、メチルメタクリレート、２－ヒドロキシエチルメタクリレート、Ｎ，Ｎ’－ジメチルアミノエチルメタクリレートなどが挙げられる。 Examples of the methacrylic acid ester monomer include butyl methacrylate, 2-ethylhexyl methacrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, N, N′-dimethylaminoethyl methacrylate and the like.
　共役ジエンモノマーとしては、ブタジエン、イソプレンなどが挙げられる。 Examples of the conjugated diene monomer include butadiene and isoprene.
　ビニルエステル化合物としては、酢酸ビニルなどが挙げられる。 Examples of vinyl ester compounds include vinyl acetate.
　α－オレフィン化合物としては、４－メチル－１－ペンテンなどが挙げられる。 Examples of α-olefin compounds include 4-methyl-1-pentene.
　上記の任意の単量体は、いずれか１種を単独で又は２種以上を組み合わせて用いることができる。上記任意の単量体の中でも、特に、スチレン、メチルメタクリレート、又はこれらの組み合わせがジビニルベンゼンおよびエチルビニルベンゼンとの反応性の観点から好ましい。 Any one of the above monomers can be used alone or in combination of two or more. Among the above optional monomers, styrene, methyl methacrylate, or a combination thereof is particularly preferable from the viewpoint of reactivity with divinylbenzene and ethylvinylbenzene.
　非導電性粒子における単量体合計重量中の任意の単量体単位の含有割合は、好ましくは３～８０質量％、より好ましくは４～７０質量％、特に好ましくは５～６０質量％である。特に、任意の単量体として、スチレン及び／又はメチルメタクリレートを含む場合、その好ましい含有割合は、非導電性粒子を構成する単量体全量を基準として、４．５～７６．５質量％である。スチレン及びメチルメタクリレートの両方を含有する場合は、それらの合計がこの範囲であることが好ましい。スチレン及び／又はメチルメタクリレートの含有割合を７６．５質量％以下とすることにより、非導電性粒子の耐熱性を向上させることができ、多孔膜の耐熱性を向上させることができ、ひいては高温における電池の短絡の発生を低減することができる。一方スチレン及び／又はメチルメタクリレートの含有割合を４．５質量％以上とすることにより、非導電性粒子の分散性が低下することを防ぎ、多孔膜の強度を高めることができ、且つ膜均一性をも得ることができる。 The content ratio of arbitrary monomer units in the total monomer weight in the non-conductive particles is preferably 3 to 80% by mass, more preferably 4 to 70% by mass, and particularly preferably 5 to 60% by mass. . In particular, when styrene and / or methyl methacrylate is included as an optional monomer, the preferable content ratio is 4.5 to 76.5% by mass based on the total amount of monomers constituting the non-conductive particles. is there. In the case where both styrene and methyl methacrylate are contained, it is preferable that the sum thereof is within this range. By setting the content ratio of styrene and / or methyl methacrylate to 76.5% by mass or less, the heat resistance of the non-conductive particles can be improved, the heat resistance of the porous film can be improved, and thus at a high temperature. Generation | occurrence | production of the short circuit of a battery can be reduced. On the other hand, by setting the content ratio of styrene and / or methyl methacrylate to 4.5% by mass or more, it is possible to prevent the dispersibility of the nonconductive particles from being lowered, to increase the strength of the porous film, and to achieve film uniformity. Can also be obtained.
（非導電性粒子の製造方法）
　非導電性粒子の製造方法は特に限定されず、非導電性粒子を構成する単量体及び必要に応じて他の任意の成分を分散媒に溶解又は分散させ、乳化重合法またはソープフリー重合法によって、かかる分散液中で重合する方法が挙げられる。 (Method for producing non-conductive particles)
The production method of the non-conductive particles is not particularly limited, and the emulsion polymerization method or the soap-free polymerization method is performed by dissolving or dispersing the monomer constituting the non-conductive particles and other optional components as necessary in a dispersion medium. To polymerize in such a dispersion.
　乳化重合においては、重合を、複数の段階に分けて行うことが、所望の粒子径及び平均円形度を得る上で好ましい。例えば、非導電性粒子を構成する単量体の一部を先に重合させることによりシードポリマー粒子を形成し、続いて、該シードポリマー粒子に他の単量体を吸収させ、その状態で重合を行い、非導電性粒子を製造することができる（シード重合法）。さらには、シードポリマー粒子の形成に際し、重合をさらに複数の段階に分けて行うことができる。 In emulsion polymerization, it is preferable to carry out the polymerization in a plurality of stages in order to obtain a desired particle diameter and average circularity. For example, a seed polymer particle is formed by first polymerizing a part of the monomer constituting the non-conductive particle, and then the other polymer is absorbed in the seed polymer particle and polymerized in that state. To produce non-conductive particles (seed polymerization method). Furthermore, when forming the seed polymer particles, the polymerization can be further divided into a plurality of stages.
　より具体的には、例えば、非導電性粒子を構成する単量体の一部を用いてシードポリマー粒子Ａを形成し、かかるシードポリマー粒子Ａと、非導電性粒子を構成する別の単量体とを用いてより大きな粒子径を有するシードポリマー粒子Ｂを形成し、さらに、かかるシードポリマー粒子Ｂと、非導電性粒子を構成する残りの単量体及び必要に応じて他の任意の成分とを用いて、さらに大きな粒子径を有する非導電性粒子を形成することができる。
　このように、シードポリマー粒子を２段階の反応で形成し、それからさらに非導電性粒子を形成することにより、安定して所望の粒子径及び平均円形度を得られるという利点がある。この場合、非導電性粒子を構成する単量体のうちの極性基含有モノマーの一部又は全部（好ましくは全部）を、シードポリマー粒子Ａ及びシードポリマー粒子Ｂを形成する際に用いることが、粒子の安定性確保のため好ましい。さらに、この場合において、シードポリマー粒子Ａを形成するための単量体として、任意の単量体であるスチレンを用いることが、シードポリマー粒子Ｂおよび非導電性粒子を形成する際、シードポリマー粒子への単量体の吸収性を確保するため好ましい。 More specifically, for example, the seed polymer particle A is formed by using a part of the monomer constituting the nonconductive particle, and the seed polymer particle A and another single amount constituting the nonconductive particle. A seed polymer particle B having a larger particle size using the body, and further, the seed polymer particle B, the remaining monomers constituting the non-conductive particles, and other optional components as necessary Can be used to form non-conductive particles having a larger particle size.
Thus, there is an advantage that a desired particle diameter and average circularity can be stably obtained by forming seed polymer particles by a two-step reaction and further forming non-conductive particles. In this case, using a part or all (preferably all) of the polar group-containing monomers of the monomers constituting the non-conductive particles when forming the seed polymer particles A and the seed polymer particles B, This is preferable for ensuring the stability of the particles. Furthermore, in this case, it is possible to use styrene, which is an arbitrary monomer, as the monomer for forming the seed polymer particles A. When forming the seed polymer particles B and the non-conductive particles, the seed polymer particles It is preferable in order to ensure the absorbability of the monomer.
　このように複数の段階に分けて重合を行う場合も含まれるため、非導電性粒子を構成する単量体は、重合に際して、その全ての単量体が混合物となった状態とされていなくてもよい。重合が複数の段階に分けて行われる場合、最終的に得られる非導電性粒子において、非導電性粒子を構成する重合単位に由来する単量体の組成が、前述した非導電性粒子を構成する単量体の組成比を満たしていることが好ましい。 Since the case where the polymerization is performed in a plurality of stages as described above is also included, the monomer constituting the nonconductive particles is not in a state where all the monomers are mixed in the polymerization. Also good. When the polymerization is carried out in a plurality of stages, the composition of the monomer derived from the polymerization unit constituting the nonconductive particles in the finally obtained nonconductive particles constitutes the nonconductive particles described above. It is preferable that the composition ratio of the monomers to be satisfied is satisfied.
　非導電性粒子を構成する単量体の重合に用いる媒体としては、水、有機溶媒、及びこれらの混合物を挙げることができる。有機溶媒としては、ラジカル重合に不活性でかつ単量体の重合を阻害しないものを用いうる。有機溶媒の具体例としては、メタノール、エタノール、プロパノール、シクロヘキサノール、オクタノールなどのアルコール類、フタル酸ジブチル、フタル酸ジオクチルなどのエステル類、シクロヘキサノンなどのケトン類、及びこれらの混合物が挙げられる。好ましくは、分散媒として水などの水性の媒体を用い、重合として乳化重合を行うことができる。 Examples of the medium used for the polymerization of the monomers constituting the nonconductive particles include water, organic solvents, and mixtures thereof. As the organic solvent, those which are inert to radical polymerization and do not inhibit the polymerization of monomers can be used. Specific examples of the organic solvent include alcohols such as methanol, ethanol, propanol, cyclohexanol and octanol, esters such as dibutyl phthalate and dioctyl phthalate, ketones such as cyclohexanone, and mixtures thereof. Preferably, an aqueous medium such as water is used as a dispersion medium, and emulsion polymerization can be performed as polymerization.
　シードポリマー粒子と単量体とを反応させる際のこれらの量比は、シードポリマー粒子１質量部に対する単量体の使用量として、好ましくは２～１９質量部、より好ましくは３～１６質量部、さらにより好ましくは４～１２質量部である。シードポリマー粒子１質量部に対する単量体の使用量を２質量部以上とすることにより、得られる非導電性粒子の機械的強度及び耐熱性を高めることができる。また、シードポリマー粒子１質量部に対する単量体の使用量を１９質量部以下とすることにより、効率よくシードポリマー粒子へ単量体を吸収させることができるため、シードポリマー粒子に吸収されない単量体量を少ない範囲に保つことができる。また、非導電性粒子の粒子径のコントロールを良好に行うことができるため、幅広い粒子径分布を持つ粗大粒子や多量の微少粒子の発生を防ぐことができる。 The amount ratio of these when the seed polymer particles and the monomer are reacted is preferably 2 to 19 parts by weight, more preferably 3 to 16 parts by weight, based on 1 part by weight of the seed polymer particles. Even more preferably, it is 4 to 12 parts by mass. By making the usage-amount of a monomer 2 mass parts or more with respect to 1 mass part of seed polymer particles, the mechanical strength and heat resistance of the nonelectroconductive particle obtained can be improved. Moreover, since the monomer can be efficiently absorbed into the seed polymer particle by setting the amount of the monomer used to 19 parts by mass or less with respect to 1 part by mass of the seed polymer particle, a single amount that is not absorbed by the seed polymer particle. The body weight can be kept in a small range. In addition, since the particle size of the non-conductive particles can be controlled well, the generation of coarse particles having a wide particle size distribution and a large amount of fine particles can be prevented.
　重合の具体的な操作としては、シードポリマー粒子の水性分散体に対して単量体を一時に投入する方法、重合を行いながら単量体を分割して又は連続的に添加する方法がある。重合が開始してシードポリマー粒子中において実質的に架橋が生ずる前にシードポリマー粒子に単量体を吸収させることが好ましい。
　重合の中期以降に単量体を添加すると、単量体がシードポリマー粒子に吸収されないため、微少粒子が多量に生じて重合安定性が悪くなり、重合反応を維持することができない場合がある。そのためシードポリマー粒子に対してすべての単量体を重合開始前に添加するか、重合転化率が３０％程度に達する前にすべての単量体の添加を終了させておくことが好ましい。特に重合の開始前にシードポリマー粒子の水性分散体に単量体を加えて撹拌し、シードポリマー粒子にこれを吸収させた後に重合を開始することが好ましい。 Specific operations for the polymerization include a method in which the monomer is added to the aqueous dispersion of seed polymer particles at a time, and a method in which the monomer is divided or continuously added while performing the polymerization. It is preferred that the monomer be absorbed by the seed polymer particles before polymerization begins and substantial crosslinking occurs in the seed polymer particles.
If the monomer is added after the middle of the polymerization, the monomer is not absorbed by the seed polymer particles, so that a large amount of fine particles are generated, the polymerization stability is deteriorated, and the polymerization reaction may not be maintained. Therefore, it is preferable to add all monomers to the seed polymer particles before the start of polymerization, or to finish adding all monomers before the polymerization conversion rate reaches about 30%. In particular, it is preferable to start the polymerization after the monomer is added to the aqueous dispersion of seed polymer particles and stirred before the polymerization starts, and the seed polymer particles absorb this.
　重合の反応系には、非導電性粒子を構成する単量体及び分散媒の他に、任意成分を加えることができる。具体的には、重合開始剤、界面活性剤、懸濁保護剤等の成分を加えることができる。重合開始剤としては、一般の水溶性のラジカル重合開始剤あるいは油溶性のラジカル重合開始剤を用いることができるが、シードポリマー粒子に吸収されない単量体が水相で重合を開始することの少ない点で水溶性のラジカル重合開始剤を用いることが好ましい。水溶性のラジカル重合開始剤としては、過硫酸カリウム、過硫酸ナトリウム、クメンハイドロパーオキサイド、過酸化水素、あるいは前記水溶性開始剤または後述の油溶性開始剤と重亜硫酸水素ナトリウムなどの還元剤との組み合わせによるレドックス系開始剤が挙げられる。また、油溶性のラジカル重合開始剤としては、ベンゾイルパーオキサイド、α，α’－アゾビスイソブチロニトリル、ｔ－ブチルパーオキシ－２－エチルヘキサノエート、３，５，５－トリメチルヘキサノイルパーオキサイドなどを挙げることができる。油溶性のラジカル重合開始剤のなかでは、ｔ－ブチルパーオキシ－２－エチルヘキサノエートを好ましく用いることができる。なお、重合反応においては、重クロム酸カリウム、塩化第２鉄、ハイドロキノンなどの水溶性の重合禁止剤を少量添加すると、微少粒子の発生を抑制することができるので好ましい。
　界面活性剤としては通常のものを用いることができ、例えばドデシルベンゼンスルホン酸ナトリウム、ラウリル硫酸ナトリウム、ジアルキルスルホコハク酸ナトリウム、ナフタレンスルホン酸のホルマリン縮合物などのアニオン系乳化剤を例示することができる。さらに、ポリオキシエチレンノニルフェニルエーテル、ポリエチレングリコールモノステアレート、ソルビタンモノステアレートなどのノニオン系界面活性剤を併用することも可能である。好ましい懸濁保護剤としては、ポリビニルアルコール、カルボキシルメチルセルロース、ポリアクリル酸ナトリウムあるいは微粉末無機化合物などを挙げることができる。 An optional component can be added to the polymerization reaction system in addition to the monomer constituting the non-conductive particles and the dispersion medium. Specifically, components such as a polymerization initiator, a surfactant, and a suspension protective agent can be added. As the polymerization initiator, a general water-soluble radical polymerization initiator or oil-soluble radical polymerization initiator can be used, but a monomer that is not absorbed by the seed polymer particles rarely initiates polymerization in the aqueous phase. In view of this, it is preferable to use a water-soluble radical polymerization initiator. Examples of the water-soluble radical polymerization initiator include potassium persulfate, sodium persulfate, cumene hydroperoxide, hydrogen peroxide, or the water-soluble initiator or an oil-soluble initiator described later and a reducing agent such as sodium bisulfite. The redox initiator by the combination of these is mentioned. Oil-soluble radical polymerization initiators include benzoyl peroxide, α, α'-azobisisobutyronitrile, t-butylperoxy-2-ethylhexanoate, 3,5,5-trimethylhexanoyl A peroxide etc. can be mentioned. Of the oil-soluble radical polymerization initiators, t-butylperoxy-2-ethylhexanoate can be preferably used. In the polymerization reaction, it is preferable to add a small amount of a water-soluble polymerization inhibitor such as potassium dichromate, ferric chloride, or hydroquinone because generation of fine particles can be suppressed.
As the surfactant, a normal one can be used, and examples thereof include anionic emulsifiers such as sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium dialkylsulfosuccinate, and a formalin condensate of naphthalenesulfonic acid. Furthermore, nonionic surfactants such as polyoxyethylene nonylphenyl ether, polyethylene glycol monostearate, sorbitan monostearate can be used in combination. Preferred examples of the suspension protective agent include polyvinyl alcohol, carboxymethyl cellulose, sodium polyacrylate, and a fine powder inorganic compound.
（非導電性粒子の性状）
　本発明に用いる非導電性粒子の形状は、球状、針状、棒状、紡錘状、板状等特に限定されないが、球状、針状、紡錘状が好ましい。また、非導電性粒子として、多孔性粒子を使用することもできる。多孔膜スラリーの全固形分１００質量％当たりの非導電性粒子の含有割合は、好ましくは７０～９７質量％、より好ましくは８０～９５質量％、特に好ましくは８５～９５質量％である。多孔膜スラリーの全固形分１００質量％当たりの非導電性粒子の含有割合を上記範囲とすることにより、高い熱安定性を示す多孔膜を得ることができる。また、非導電性粒子の多孔膜からの脱離（粉落ち）を抑制し、高い強度を示す多孔膜を得ることができると共に、サイクル特性等の電池特性の低下を防ぐことができる。 (Properties of non-conductive particles)
The shape of the non-conductive particles used in the present invention is not particularly limited, such as a spherical shape, a needle shape, a rod shape, a spindle shape, and a plate shape, but a spherical shape, a needle shape, and a spindle shape are preferable. Moreover, porous particles can also be used as the non-conductive particles. The content ratio of the non-conductive particles per 100% by mass of the total solid content of the porous membrane slurry is preferably 70 to 97% by mass, more preferably 80 to 95% by mass, and particularly preferably 85 to 95% by mass. By setting the content ratio of the nonconductive particles per 100% by mass of the total solid content of the porous membrane slurry within the above range, a porous membrane exhibiting high thermal stability can be obtained. In addition, desorption (powder removal) of non-conductive particles from the porous film can be suppressed, and a porous film having high strength can be obtained, and deterioration of battery characteristics such as cycle characteristics can be prevented.
　非導電性粒子が高い耐熱性を有することが、多孔膜に耐熱性を付与し、後述する二次電池電極や二次電池セパレーターの信頼性を向上させる観点から好ましい。具体的には、窒素雰囲気下における熱天秤分析において昇温速度１０℃／分で加熱したときの非導電性粒子の減量割合が１０質量％に達する温度が、好ましくは２５０℃以上、より好ましくは３００℃以上、特に好ましくは３６０℃以上である。一方、当該温度の上限は特に制限されないが、例えば４５０℃以下とすることができる。 It is preferable that the non-conductive particles have high heat resistance from the viewpoint of imparting heat resistance to the porous film and improving the reliability of a secondary battery electrode and a secondary battery separator described later. Specifically, the temperature at which the weight loss rate of the non-conductive particles reaches 10% by mass when heated at a heating rate of 10 ° C./min in a thermobalance analysis in a nitrogen atmosphere is preferably 250 ° C. or more, more preferably It is 300 ° C. or higher, particularly preferably 360 ° C. or higher. On the other hand, the upper limit of the temperature is not particularly limited, but can be, for example, 450 ° C. or less.
　本発明においては、非導電性粒子として、金属異物の含有量が１００ｐｐｍ以下のものを用いることが好ましい。金属異物または金属イオンが多く含まれる非導電性粒子を用いると、多孔膜スラリー中において、前記金属異物又は金属イオンが溶出し、これが多孔膜スラリー中のポリマーとイオン架橋を起こし、多孔膜スラリーが凝集し結果として多孔膜の多孔性が下がる。そのため、該多孔膜を用いた二次電池のレート特性（出力特性）が悪化する恐れがある。前記金属としては、特にＣａ、Ｃｏ、Ｃｕ、Ｆｅ、Ｍｇ、Ｎｉ、ＺｎおよびＣｒ等の含有が最も好ましくない。従って、非導電性粒子中の金属含有量としては、これらの金属イオンの合計量で、好ましくは１００ｐｐｍ以下、更に好ましくは５０ｐｐｍ以下である。上記含有量が少ないほど電池特性の劣化が起こりにくくなる。ここでいう「金属異物」とは、非導電性粒子以外の金属単体または金属イオンを意味する。非導電性粒子中の金属異物の含有量は、ＩＣＰ（Ｉｎｄｕｃｔｉｖｅｌｙ　Ｃｏｕｐｌｅｄ　Ｐｌａｓｍａ）を用いて測定することができる。 In the present invention, it is preferable to use non-conductive particles having a metal foreign matter content of 100 ppm or less. When non-conductive particles containing a large amount of metal foreign matter or metal ions are used, the metal foreign matter or metal ions are eluted in the porous membrane slurry, and this causes ionic crosslinking with the polymer in the porous membrane slurry. Aggregation results in a decrease in the porosity of the porous membrane. Therefore, there is a possibility that the rate characteristic (output characteristic) of the secondary battery using the porous film is deteriorated. As the metal, the inclusion of Ca, Co, Cu, Fe, Mg, Ni, Zn, Cr and the like is most undesirable. Therefore, the metal content in the non-conductive particles is preferably 100 ppm or less, more preferably 50 ppm or less, in terms of the total amount of these metal ions. The smaller the content, the less likely the battery characteristics will deteriorate. As used herein, “metal foreign matter” means a simple metal or a metal ion other than non-conductive particles. The content of the metal foreign matter in the non-conductive particles can be measured using ICP (Inductively Coupled Plasma).
　本発明に用いる非導電性粒子の平均粒子径は、好ましくは０．１～２μｍ、より好ましくは０．１～１μｍ、特に好ましくは０．１～０．８μｍである。非導電性粒子の平均粒子径を前記範囲とすることにより、多孔膜スラリーの分散状態の制御がしやすくなるため、均質な所定厚みの多孔膜の製造が容易になる。また、多孔膜中の粒子充填率が高くなることを抑制できるため、多孔膜中のイオン伝導性が低下することを抑制でき、優れたサイクル特性を実現できる。非導電性粒子の平均粒子径を、０．１～０．８μｍの範囲にすると、分散、塗布の容易さ、空隙のコントロール性に優れるので特に好ましい。平均粒子径は、電子顕微鏡観察を行い、１００個以上の粒子について、その粒子像の最長辺をａ、最短辺をｂとし、（ａ＋ｂ）／２を算出し、その平均値から求めることができる。 The average particle diameter of the non-conductive particles used in the present invention is preferably 0.1 to 2 μm, more preferably 0.1 to 1 μm, and particularly preferably 0.1 to 0.8 μm. By making the average particle diameter of the non-conductive particles within the above range, it becomes easy to control the dispersion state of the porous film slurry, so that it becomes easy to produce a porous film having a uniform predetermined thickness. Moreover, since it can suppress that the particle filling rate in a porous film becomes high, it can suppress that the ionic conductivity in a porous film falls, and can implement | achieve the outstanding cycling characteristics. It is particularly preferable that the average particle diameter of the non-conductive particles is in the range of 0.1 to 0.8 μm because the dispersion, the ease of coating, and the controllability of the voids are excellent. The average particle diameter can be obtained from an average value obtained by observing an electron microscope and calculating (a + b) / 2 by taking the longest side of the particle image as a and the shortest side as b for 100 or more particles. .
　本発明に用いる非導電性粒子の平均円形度は、好ましくは０．９００～０．９９５、より好ましくは０．９１～０．９８、特に好ましくは０．９２～０．９７である。非導電性粒子の平均円形度を前記範囲とすることにより、非導電性粒子同士の接触面積を適度に保つことができるため、多孔膜の強度及び耐熱性を向上させることができる。その結果、該多孔膜を用いた二次電池の信頼性を向上させることができる。 The average circularity of the nonconductive particles used in the present invention is preferably 0.900 to 0.995, more preferably 0.91 to 0.98, and particularly preferably 0.92 to 0.97. By setting the average circularity of the non-conductive particles in the above range, the contact area between the non-conductive particles can be kept moderate, and the strength and heat resistance of the porous film can be improved. As a result, the reliability of the secondary battery using the porous film can be improved.
　また、本発明に用いる非導電性粒子のＢＥＴ比表面積は、非導電性粒子の凝集を抑制し、多孔膜スラリーの流動性を好適化する観点から具体的には、０．９～２００ｍ２／ｇであることが好ましく、１．５～１５０ｍ２／ｇであることがより好ましい。 Further, the BET specific surface area of the non-conductive particles used in the present invention is specifically 0.9 to 200 m 2 / from the viewpoint of suppressing aggregation of the non-conductive particles and optimizing the fluidity of the porous membrane slurry. g is preferable, and 1.5 to 150 m 2 / g is more preferable.
　非導電性粒子の粒子径分布は、好ましくは１．００～１．４、より好ましくは１．００～１．３、特に好ましくは１．００～１．２である。非導電性粒子の粒子径分布を前記範囲とすることにより、非導電性粒子間において所定の空隙を保つことができるため、本発明の二次電池中においてリチウムの移動を阻害し抵抗が増大することを抑制することができる。なお、非導電性粒子の粒子径分布は、ベックマン株式会社製のレーザー回折散乱粒度分布測定装置（ＬＳ２３０）にて粒子径測定を行った後、得られた体積平均粒子径Ｖと数平均粒子径Ｎとの比Ｖ／Ｎで求めることができる。 The particle size distribution of the non-conductive particles is preferably 1.00 to 1.4, more preferably 1.00 to 1.3, and particularly preferably 1.00 to 1.2. By setting the particle size distribution of the non-conductive particles within the above range, a predetermined gap can be maintained between the non-conductive particles, so that the lithium migration is inhibited and the resistance is increased in the secondary battery of the present invention. This can be suppressed. In addition, the particle size distribution of the non-conductive particles is obtained by measuring the particle size with a laser diffraction scattering particle size distribution measuring device (LS230) manufactured by Beckman Co., Ltd., and then obtaining the volume average particle size V and the number average particle size. It can be determined by the ratio V / N with N.
（バインダー）
　本発明に用いるバインダーは、スルホン酸基を有するアクリル重合体粒子Ａ、及びエポキシ基を有するアクリル重合体粒子Ｂを含む。本発明においては、該アクリル重合体粒子Ａ及び該アクリル重合体粒子Ｂを含むバインダーを用いることで、多孔膜スラリーのゲル化を防止することができるため、均一な多孔膜を形成することができる。 (binder)
The binder used in the present invention includes acrylic polymer particles A having sulfonic acid groups and acrylic polymer particles B having epoxy groups. In the present invention, by using the binder containing the acrylic polymer particles A and the acrylic polymer particles B, gelation of the porous film slurry can be prevented, so that a uniform porous film can be formed. .
　スルホン酸基を有するアクリル重合体粒子Ａは、スルホン酸基を有する単量体単位を含んでなる。具体的には、アクリル重合体粒子Ａとしての重合体中に、スルホン酸基を有する単量体単位を含むことを特徴とする。 The acrylic polymer particle A having a sulfonic acid group includes a monomer unit having a sulfonic acid group. Specifically, the polymer as the acrylic polymer particle A includes a monomer unit having a sulfonic acid group.
　スルホン酸基を有する単量体としては、ビニルスルホン酸、メチルビニルスルホン酸、（メタ）アリルスルホン酸、スチレンスルホン酸、（メタ）アクリル酸－２－スルホン酸エチル、２－アクリルアミド－２－メチルプロパンスルホン酸、３－アリロキシ－２－ヒドロキシプロパンスルホン酸、スチレンスルホン酸ナトリウムなどが挙げられる。 Examples of monomers having a sulfonic acid group include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylic acid-2-ethyl sulfonate, 2-acrylamido-2-methyl. Examples thereof include propanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, sodium styrenesulfonate, and the like.
　アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は、好ましくは０．３～１０質量％、より好ましくは１．３～９質量％である。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合が上記範囲であると、バインダーに良好な結着性を付与でき、非導電性粒子の多孔膜からの脱離(粉落ち)を抑制することができる。 The content ratio of the monomer unit having a sulfonic acid group in the acrylic polymer particle A is preferably 0.3 to 10% by mass, more preferably 1.3 to 9% by mass. When the content ratio of the monomer unit having a sulfonic acid group in the acrylic polymer particle A is in the above range, the binder can be provided with a good binding property, and the non-conductive particles are detached from the porous film (powder off). ) Can be suppressed.
　アクリル重合体粒子Ａにおけるスルホン酸基の含有割合は、好ましくは０．０４～５．８質量％、より好ましくは０．１～４質量％、特に好ましくは０．５～３．５質量％である。アクリル重合体粒子Ａにおけるスルホン酸基の含有割合が上記範囲であると、多孔膜スラリーの粘度上昇を防止し、多孔膜スラリーの塗工性を良好に保つことができる。また、非導電性粒子に対して十分な結着力を有すると共に、後述するアクリル重合体粒子Ｂのエポキシ基との反応性が高くなる。さらにまた、多孔膜スラリーにおける非導電性粒子の分散性を向上させる。 The content ratio of the sulfonic acid group in the acrylic polymer particles A is preferably 0.04 to 5.8% by mass, more preferably 0.1 to 4% by mass, and particularly preferably 0.5 to 3.5% by mass. is there. When the content ratio of the sulfonic acid group in the acrylic polymer particles A is within the above range, the increase in the viscosity of the porous film slurry can be prevented, and the coating property of the porous film slurry can be kept good. Moreover, while having sufficient binding force with respect to a nonelectroconductive particle, the reactivity with the epoxy group of the acrylic polymer particle B mentioned later becomes high. Furthermore, the dispersibility of the nonconductive particles in the porous membrane slurry is improved.
　アクリル重合体粒子Ａは、スルホン酸基を有する単量体単位以外に、（メタ）アクリロニトリル単量体単位を更に含むことが好ましい。アクリル重合体粒子Ａにおける（メタ）アクリロニトリル単量体単位の含有割合は、好ましくは２．５～４０質量％、より好ましくは３～３７質量％、特に好ましくは５～３５質量％である。アクリル重合体粒子Ａにおける（メタ）アクリロニトリル単量体単位の含有割合が上記範囲であると、バインダーの強度が向上するため、優れたサイクル特性を有する二次電池を製造することができる。 The acrylic polymer particle A preferably further contains a (meth) acrylonitrile monomer unit in addition to the monomer unit having a sulfonic acid group. The content ratio of the (meth) acrylonitrile monomer unit in the acrylic polymer particles A is preferably 2.5 to 40% by mass, more preferably 3 to 37% by mass, and particularly preferably 5 to 35% by mass. When the content ratio of the (meth) acrylonitrile monomer unit in the acrylic polymer particles A is within the above range, the strength of the binder is improved, so that a secondary battery having excellent cycle characteristics can be manufactured.
　また、本発明において、スルホン酸基を有するアクリル重合体粒子Ａが、上記単量体単位以外に、（メタ）アクリル酸エステル単量体単位を更に含むことが好ましい。アクリル重合体粒子Ａにおける（メタ）アクリル酸エステル単量体単位の含有割合は、好ましくは６０～９７．５質量％、より好ましくは６２～９６質量％、特に好ましくは６５～９５質量％である。アクリル重合体粒子Ａにおける（メタ）アクリル酸エステル単量体単位の含有割合が上記範囲であると、バインダーが二次電池の電解液に溶出せずに電解液への適度な膨潤性を示すため、リチウムイオンの伝導性を良好に保つことができる。その結果、二次電池のサイクル特性を向上させることができる。 In the present invention, it is preferable that the acrylic polymer particle A having a sulfonic acid group further contains a (meth) acrylic acid ester monomer unit in addition to the monomer unit. The content ratio of the (meth) acrylic acid ester monomer unit in the acrylic polymer particles A is preferably 60 to 97.5% by mass, more preferably 62 to 96% by mass, and particularly preferably 65 to 95% by mass. . When the content ratio of the (meth) acrylic acid ester monomer unit in the acrylic polymer particle A is in the above range, the binder does not elute into the electrolytic solution of the secondary battery and exhibits an appropriate swelling property to the electrolytic solution. The lithium ion conductivity can be kept good. As a result, the cycle characteristics of the secondary battery can be improved.
　（メタ）アクリル酸エステル単量体としては、メチルアクリレート、エチルアクリレート、ｎ－プロピルアクリレート、イソプロピルアクリレート、ｎ－ブチルアクリレート、ｔ－ブチルアクリレート、ペンチルアクリレート、ヘキシルアクリレート、ヘプチルアクリレート、オクチルアクリレート、２－エチルヘキシルアクリレート、ノニルアクリレート、デシルアクリレート、ラウリルアクリレート、ｎ－テトラデシルアクリレート、ステアリルアクリレートなどのアクリル酸アルキルエステル；メチルメタクリレート、エチルメタクリレート、ｎ－プロピルメタクリレート、イソプロピルメタクリレート、ｎ－ブチルメタクリレート、ｔ－ブチルメタクリレート、ペンチルメタクリレート、ヘキシルメタクリレート、ヘプチルメタクリレート、オクチルメタクリレート、２－エチルヘキシルメタクリレート、ノニルメタクリレート、デシルメタクリレート、ラウリルメタクリレート、ｎ－テトラデシルメタクリレート、ステアリルメタクリレートなどのメタクリル酸アルキルエステルが挙げられる。これらの中でも、電解液に溶出せずに電解液への適度な膨潤によるリチウムイオンの伝導性を示すこと、加えて活物質の分散においてポリマーによる橋架け凝集を起こしにくいことから非カルボニル性酸素原子に結合するアルキル基の炭素数が２～１３のエチル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、ラウリル（メタ）アクリレートが好ましく、中でも非カルボニル性酸素原子に結合するアルキル基の炭素数が４～１０である、ｎ－ブチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレートが好ましい。 Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2- Acrylic acid alkyl esters such as ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate , Pentyl methacrylate, hexyl methacrylate, heptyl methacrylate Rate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n- tetradecyl methacrylate, methacrylic acid alkyl esters such as stearyl methacrylate. Among these, non-carbonylic oxygen atoms are shown because they exhibit lithium ion conductivity by moderate swelling into the electrolyte without eluting into the electrolyte, and in addition, they are less likely to cause bridging aggregation by the polymer in the dispersion of the active material. Preferred are ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate having 2 to 13 carbon atoms in the alkyl group bonded to Preferred are n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, in which the alkyl group to be bonded has 4 to 10 carbon atoms.
　さらに、アクリル重合体粒子Ａは、上記単量体単位（スルホン酸基を有する単量体単位、（メタ）アクリロニトリル単量体単位、及び（メタ）アクリル酸エステル単量体単位）以外に、これらと共重合可能な他の単量体単位を含むことが好ましい。アクリル重合体粒子Ａにおける他の単量体単位の含有割合は、好ましくは０．１～１０質量％、より好ましくは０．１～５質量％である。アクリル重合体粒子Ａにおける他の単量体単位の含有割合が上記範囲であると、粒子の分散性が低下することがなく、均一に多孔膜を形成することが可能となる。 Further, the acrylic polymer particles A are in addition to the above monomer units (monomer units having a sulfonic acid group, (meth) acrylonitrile monomer units, and (meth) acrylic acid ester monomer units). It is preferable to contain other monomer units copolymerizable with. The content ratio of the other monomer units in the acrylic polymer particles A is preferably 0.1 to 10% by mass, more preferably 0.1 to 5% by mass. When the content ratio of the other monomer units in the acrylic polymer particles A is in the above range, the dispersibility of the particles does not decrease, and a porous film can be formed uniformly.
　他の単量体としては、スチレン、クロロスチレン、ビニルトルエン、ｔ－ブチルスチレン、ビニル安息香酸、ビニル安息香酸メチル、ビニルナフタレン、クロロメチルスチレン、α－メチルスチレン、ジビニルベンゼン等のスチレン系単量体；アクリル酸、メタクリル酸、クロトン酸、２－エチルアクリル酸、イソクロトン酸、α－アセトキシアクリル酸、β－ｔｒａｎｓ－アリールオキシアクリル酸、α－クロロ－β－Ｅ－メトキシアクリル酸、β－ジアミノアクリル酸等のモノカルボン酸を有するエチレン系不飽和カルボン酸；マレイン酸、フマル酸、イタコン酸、メチルマレイン酸、ジメチルマレイン酸、フェニルマレイン酸、クロロマレイン酸、ジクロロマレイン酸、フルオロマレイン酸、及びマレイン酸エステル等のジカルボン酸を有するエチレン系不飽和カルボン酸及びその誘導体；エチレン、プロピレン等のオレフィン類；ブタジエン、イソプレン等のジエン系単量体；塩化ビニル、塩化ビニリデン等のハロゲン原子含有単量体；酢酸ビニル、プロピオン酸ビニル、酪酸ビニル等のビニルエステル類；メチルビニルエーテル、エチルビニルエーテル、ブチルビニルエーテル等のビニルエーテル類；メチルビニルケトン、エチルビニルケトン、ブチルビニルケトン、ヘキシルビニルケトン、イソプロペニルビニルケトン等のビニルケトン類；Ｎ－ビニルピロリドン、ビニルピリジン、ビニルイミダゾール等の複素環含有ビニル化合物；アクリルアミド、Ｎ－メチロールアクリルアミドなどのアミド系単量体；などが挙げられる。なお、アクリル重合体粒子Ａは、他の単量体単位を、１種類だけ含んでいてもよく、２種類以上を任意の比率で組み合わせて含んでいてもよい。 Other monomers include styrene-based monomers such as styrene, chlorostyrene, vinyltoluene, t-butylstyrene, vinylbenzoic acid, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, α-methylstyrene, and divinylbenzene. Acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, isocrotonic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, β-diamino An ethylenically unsaturated carboxylic acid having a monocarboxylic acid such as acrylic acid; maleic acid, fumaric acid, itaconic acid, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, and Dicarboxylic acid such as maleate ester Ethylenically unsaturated carboxylic acids and derivatives thereof; olefins such as ethylene and propylene; diene monomers such as butadiene and isoprene; halogen atom-containing monomers such as vinyl chloride and vinylidene chloride; vinyl acetate and vinyl propionate Vinyl esters such as vinyl butyrate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and butyl vinyl ether; vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone and isopropenyl vinyl ketone; N-vinyl And heterocyclic ring-containing vinyl compounds such as pyrrolidone, vinylpyridine and vinylimidazole; amide monomers such as acrylamide and N-methylolacrylamide; The acrylic polymer particle A may contain only one type of other monomer unit, or may contain two or more types combined in any ratio.
　エポキシ基を有するアクリル重合体粒子Ｂは、エポキシ基を有する単量体単位を含んでなる。具体的には、アクリル重合体粒子Ｂとしての重合体中に、エポキシ基を有する単量体単位を含むことを特徴とする。 The acrylic polymer particle B having an epoxy group comprises a monomer unit having an epoxy group. Specifically, the polymer as the acrylic polymer particle B includes a monomer unit having an epoxy group.
　エポキシ基を有する単量体としては、ビニルグリシジルエーテル、アリルグリシジルエーテル、ブテニルグリシジルエーテル、ｏ－アリルフェニルグリシジルエーテルなどの不飽和グリシジルエーテル；ブタジエンモノエポキシド、クロロプレンモノエポキシド、４，５－エポキシ－２－ペンテン、３，４－エポキシ－１－ビニルシクロヘキセン、１，２－エポキシ－５，９－シクロドデカジエンなどのジエンまたはポリエンのモノエポキシド；３，４－エポキシ－１－ブテン、１，２－エポキシ－５－ヘキセン、１，２－エポキシ－９－デセンなどのアルケニルエポキシド；グリシジルアクリレート、グリシジルメタクリレート、グリシジルクロトネート、グリシジル－４－ヘプテノエート、グリシジルソルベート、グリシジルリノレート、グリシジル－４－メチル－３－ペンテノエート、３－シクロヘキセンカルボン酸のグリシジルエステル、４－メチル－３－シクロヘキセンカルボン酸のグリシジルエステルなどの不飽和カルボン酸のグリシジルエステル類；が挙げられる。中でも、酸官能性基との反応性が高いことから、得られる多孔膜の結着性が高く粉落ちが低く、多孔膜を用いた電池のサイクル特性に優れることから、ビニルグリシジルエーテル、アリルグリシジルエーテル、グリシジルアクリレート、グリシジルメタクリレートが好ましく、グリシジルアクリレート、グリシジルメタクリレートが最も好ましい。 Monomers having an epoxy group include unsaturated glycidyl ethers such as vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o-allylphenyl glycidyl ether; butadiene monoepoxide, chloroprene monoepoxide, 4,5-epoxy- Diene or polyene monoepoxides such as 2-pentene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene; 3,4-epoxy-1-butene, 1,2 Alkenyl epoxides such as epoxy-5-hexene and 1,2-epoxy-9-decene; glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, glycidyl-4-heptenoate, glycidyl sorbate, glycidyl linoleate , Glycidyl-4-methyl-3-pentenoate, 3-glycidyl ester of cyclohexene carboxylic acid, glycidyl esters of unsaturated carboxylic acids such as 4-methyl-3-glycidyl ester of cyclohexene carboxylic acids; and the like. Among them, since the reactivity with the acid functional group is high, the binding property of the obtained porous film is high, the powder fall is low, and the cycle characteristics of the battery using the porous film are excellent. Therefore, vinyl glycidyl ether, allyl glycidyl Ether, glycidyl acrylate and glycidyl methacrylate are preferred, and glycidyl acrylate and glycidyl methacrylate are most preferred.
　アクリル重合体粒子Ｂにおけるエポキシ基を有する単量体単位の含有割合は、好ましくは０．３～８質量％、より好ましくは０．３～５質量％である。アクリル重合体粒子Ｂにおけるエポキシ基を有する単量体単位の含有割合が上記範囲であると、バインダーに良好な結着性を付与でき、非導電性粒子の多孔膜からの脱離(粉落ち)を抑制することができる。 The content ratio of the monomer unit having an epoxy group in the acrylic polymer particle B is preferably 0.3 to 8% by mass, more preferably 0.3 to 5% by mass. When the content ratio of the monomer unit having an epoxy group in the acrylic polymer particle B is in the above range, the binder can be provided with a favorable binding property, and the non-conductive particles are detached from the porous film (powder off). Can be suppressed.
　アクリル重合体粒子Ｂにおけるエポキシ基の含有割合は、好ましくは０．０３～３．０質量％、より好ましくは０．１～２．５質量％、特に好ましくは０．１～１．５質量％である。アクリル重合体粒子Ｂにおけるエポキシ基の含有割合が上記範囲であると、多孔膜スラリーの粘度上昇を防止し、多孔膜スラリーの塗工性を良好に保つことができる。また、上述したアクリル重合体粒子Ａのスルホン酸基との反応性が高くなるため、多孔膜の強度が向上する。 The content ratio of the epoxy group in the acrylic polymer particle B is preferably 0.03 to 3.0% by mass, more preferably 0.1 to 2.5% by mass, and particularly preferably 0.1 to 1.5% by mass. It is. When the content ratio of the epoxy group in the acrylic polymer particles B is within the above range, the viscosity of the porous film slurry can be prevented from increasing, and the coating property of the porous film slurry can be kept good. Moreover, since the reactivity with the sulfonic acid group of the acrylic polymer particle A mentioned above becomes high, the intensity | strength of a porous film improves.
　アクリル重合体粒子Ｂは、エポキシ基を有する単量体単位以外に、（メタ）アクリロニトリル単量体単位、（メタ）アクリル酸エステル単量体単位及びこれらと共重合可能な他の単量体単位を更に含むことが好ましい。アクリル粒子Ｂにおける（メタ）アクリロニトリル単量体単位の含有割合、（メタ）アクリル酸エステル単量体単位の含有割合及びこれらと共重合可能な他の単量体単位の含有割合は、上述したアクリル重合体粒子Ａにおける含有割合と同様である。また、各単量体は、上述したアクリル重合体粒子Ａにおける単量体と同様の単量体を例示することができる。 Acrylic polymer particles B include (meth) acrylonitrile monomer units, (meth) acrylic acid ester monomer units and other monomer units copolymerizable therewith, in addition to monomer units having an epoxy group. It is preferable that it is further included. The content ratio of the (meth) acrylonitrile monomer unit in the acrylic particles B, the content ratio of the (meth) acrylic acid ester monomer unit, and the content ratio of other monomer units copolymerizable therewith are the above-mentioned acrylic. It is the same as the content ratio in the polymer particle A. Moreover, each monomer can illustrate the monomer similar to the monomer in the acrylic polymer particle A mentioned above.
　アクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は、好ましくは０．３～３、より好ましくは０．４～３、特に好ましくは０．５～２である。アクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比を上記範囲にすることで、多孔膜スラリーのゲル化（粘度上昇）を防止し、多孔膜スラリーの塗工性を良好にすることができ、得られる多孔膜の強度が向上する。 The weight ratio of the acrylic polymer particles A to the acrylic polymer particles B (acrylic polymer particles A / acrylic polymer particles B) is preferably 0.3 to 3, more preferably 0.4 to 3, particularly preferably 0. .5-2. By setting the weight ratio of the acrylic polymer particles A to the acrylic polymer particles B within the above range, gelation (viscosity increase) of the porous membrane slurry can be prevented, and the coating property of the porous membrane slurry can be improved. The strength of the obtained porous membrane is improved.
　アクリル重合体粒子Ａ及びアクリル重合体粒子Ｂは、分散媒（水または有機溶媒）に分散された分散液または溶解された溶液の状態で使用される（以下、「重合体粒子分散液Ａ」及び「重合体粒子分散液Ｂ」と記載することがある。）。本発明においては、環境の観点に優れ、乾燥速度が速いという観点から分散媒として水を用いることが好ましい。また、分散媒として有機溶媒を用いる場合、Ｎ－メチルピロリドン（ＮＭＰ）等の有機溶剤が用いられる。 The acrylic polymer particles A and the acrylic polymer particles B are used in the state of a dispersion or dissolved solution dispersed in a dispersion medium (water or organic solvent) (hereinafter referred to as “polymer particle dispersion A” and It may be described as “polymer particle dispersion B”). In the present invention, it is preferable to use water as a dispersion medium from the viewpoints of excellent environmental viewpoint and high drying speed. When an organic solvent is used as the dispersion medium, an organic solvent such as N-methylpyrrolidone (NMP) is used.
　アクリル重合体粒子Ａ及びアクリル重合体粒子Ｂが分散媒に粒子状で分散している場合において、粒子状で分散しているアクリル重合体粒子Ａ及びアクリル重合体粒子Ｂの平均粒子径（分散粒子径）は、０．０５～０．５μｍが好ましく、０．０７～０．４μｍがさらに好ましく、最も好ましくは０．１～０．２５μｍである。アクリル重合体粒子Ａ及びアクリル重合体粒子Ｂの平均粒子径が上記範囲であると、得られる多孔膜の強度および柔軟性が良好となる。 When acrylic polymer particles A and acrylic polymer particles B are dispersed in a dispersion medium, the average particle diameter of dispersed acrylic polymer particles A and acrylic polymer particles B (dispersed particles) The diameter is preferably 0.05 to 0.5 μm, more preferably 0.07 to 0.4 μm, and most preferably 0.1 to 0.25 μm. When the average particle diameter of the acrylic polymer particles A and the acrylic polymer particles B is in the above range, the strength and flexibility of the obtained porous film are improved.
　アクリル重合体粒子Ａ及びアクリル重合体粒子Ｂが分散媒に粒子状で分散している場合において、分散液の固形分濃度は、通常１５～７０質量％であり、２０～６５質量％が好ましく、３０～６０質量％がさらに好ましい。固形分濃度がこの範囲であると、多孔膜スラリーを製造する際における作業性が良好である。 When the acrylic polymer particles A and the acrylic polymer particles B are dispersed in the dispersion medium in a particulate form, the solid content concentration of the dispersion is usually 15 to 70% by mass, preferably 20 to 65% by mass, More preferably, it is 30 to 60% by mass. When the solid content concentration is within this range, workability in producing the porous membrane slurry is good.
　本発明に用いるアクリル重合体粒子Ａ及びＢのガラス転移温度（Ｔｇ）は、好ましくは－５０～２５℃、より好ましくは－４５～１５℃、特に好ましくは－４０～５℃である。アクリル重合体粒子Ａ及びアクリル重合体粒子ＢのＴｇが上記範囲にあることにより、本発明の多孔膜が優れた強度と柔軟性を有するため、該多孔膜を用いた二次電池の出力特性を向上させることができる。なお、アクリル重合体粒子Ａ及びアクリル重合体粒子Ｂのガラス転移温度は、様々なモノマーを組み合わせることによって調製可能である。 The glass transition temperature (Tg) of the acrylic polymer particles A and B used in the present invention is preferably −50 to 25 ° C., more preferably −45 to 15 ° C., and particularly preferably −40 to 5 ° C. Since the porous film of the present invention has excellent strength and flexibility when the Tg of the acrylic polymer particle A and the acrylic polymer particle B is in the above range, the output characteristics of the secondary battery using the porous film are Can be improved. The glass transition temperatures of the acrylic polymer particles A and the acrylic polymer particles B can be prepared by combining various monomers.
　本発明に用いるアクリル重合体粒子Ａ及びアクリル重合体粒子Ｂの製造方法は特に限定はされず、溶液重合法、懸濁重合法、塊状重合法、乳化重合法などのいずれの方法も用いることができる。重合反応としては、イオン重合、ラジカル重合、リビングラジカル重合などいずれの反応も用いることができる。重合に用いる重合開始剤としては、たとえば過酸化ラウロイル、ジイソプロピルパーオキシジカーボネート、ジ－２－エチルヘキシルパーオキシジカーボネート、ｔ－ブチルパーオキシピバレート、３，３，５－トリメチルヘキサノイルパーオキサイドなどの有機過酸化物、α，α’－アゾビスイソブチロニトリルなどのアゾ化合物、または過硫酸アンモニウム、過硫酸カリウムなどがあげられる。 The production method of the acrylic polymer particles A and the acrylic polymer particles B used in the present invention is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method may be used. it can. As the polymerization reaction, any reaction such as ionic polymerization, radical polymerization, and living radical polymerization can be used. Examples of the polymerization initiator used for the polymerization include lauroyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butyl peroxypivalate, 3,3,5-trimethylhexanoyl peroxide, and the like. Organic peroxides, azo compounds such as α, α′-azobisisobutyronitrile, ammonium persulfate, potassium persulfate, and the like.
　本発明に用いるアクリル重合体粒子Ａ及びアクリル重合体粒子Ｂは、その製造工程において、重合体粒子分散液Ａ及び重合体粒子分散液Ｂに含まれる粒子状の金属を除去する粒子状金属除去工程を経て得られたものであることが好ましい。重合体粒子分散液Ａ及び重合体粒子分散液Ｂに含まれる粒子状金属成分の含有量が１０ｐｐｍ以下であることにより、多孔膜スラリー中のポリマー間の経時での金属イオン架橋を防止し、粘度上昇を防ぐことができる。さらに二次電池の内部短絡や充電時の溶解・析出による自己放電増大の懸念が少なく、電池のサイクル特性や安全性が向上する。 Acrylic polymer particles A and acrylic polymer particles B used in the present invention have a particulate metal removal step of removing particulate metals contained in the polymer particle dispersion A and the polymer particle dispersion B in the production process. It is preferable that it was obtained through this. The content of the particulate metal component contained in the polymer particle dispersion A and the polymer particle dispersion B is 10 ppm or less, thereby preventing metal ion cross-linking between the polymers in the porous membrane slurry over time, and the viscosity. The rise can be prevented. Furthermore, there is little concern about self-discharge increase due to internal short circuit of the secondary battery or dissolution / precipitation during charging, and the cycle characteristics and safety of the battery are improved.
　前記粒子状金属除去工程における重合体粒子分散液Ａ及び重合体粒子分散液Ｂから粒子状の金属成分を除去する方法は特に限定されず、例えば、濾過フィルターによる濾過により除去する方法、振動ふるいにより除去する方法、遠心分離により除去する方法、磁力により除去する方法等が挙げられる。中でも、除去対象が金属成分であるため磁力により除去する方法が好ましい。磁力により除去する方法としては、金属成分が除去できる方法であれば特に限定はされないが、生産性および除去効率を考慮すると、好ましくはアクリル重合体粒子Ａ及びアクリル重合体粒子Ｂの製造ライン中に磁気フィルターを配置することで行われる。 The method for removing the particulate metal component from the polymer particle dispersion A and the polymer particle dispersion B in the particulate metal removal step is not particularly limited. Examples of the removal method include a removal method by centrifugation, a removal method by magnetic force, and the like. Especially, since the removal object is a metal component, the method of removing by magnetic force is preferable. The method for removing by magnetic force is not particularly limited as long as the metal component can be removed. However, in consideration of productivity and removal efficiency, it is preferably in the production line of acrylic polymer particles A and acrylic polymer particles B. This is done by placing a magnetic filter.
　本発明に用いるバインダーの製造方法は、特に限定されず、上述した重合体粒子分散液Ａ及び重合体粒子分散液Ｂを混合することにより製造される。混合装置は、重合体粒子分散液Ａ及び重合体粒子分散液Ｂを均一に混合できる装置であれば特に限定されず、例えば、撹拌式、振とう式、および回転式などの混合装置を使用した方法が挙げられる。また、ホモジナイザー、ボールミル、サンドミル、ロールミル、プラネタリーミキサーおよび遊星式混練機などの分散混練装置を使用した方法が挙げられる。 The method for producing the binder used in the present invention is not particularly limited, and is produced by mixing the polymer particle dispersion A and the polymer particle dispersion B described above. The mixing device is not particularly limited as long as it can uniformly mix the polymer particle dispersion A and the polymer particle dispersion B. For example, a mixing device such as a stirring type, a shaking type, and a rotary type is used. A method is mentioned. In addition, a method using a dispersion kneader such as a homogenizer, a ball mill, a sand mill, a roll mill, a planetary mixer, and a planetary kneader can be used.
　バインダーにおけるアクリル重合体粒子Ａの含有割合は、好ましくは３０～７５質量％、より好ましくは３３～６６質量％であり、バインダーにおけるアクリル重合体粒子Ｂの含有割合は、好ましくは２５～７０質量％、より好ましくは３３～６６質量％である。バインダーにおけるアクリル重合体粒子Ａ及びアクリル重合体粒子Ｂの含有割合が上記範囲であると、結着力が良好であり、また、バインダーが増粘することなく分散するため、多孔膜の平滑性にも優れる。 The content ratio of the acrylic polymer particles A in the binder is preferably 30 to 75% by mass, more preferably 33 to 66% by mass, and the content ratio of the acrylic polymer particles B in the binder is preferably 25 to 70% by mass. More preferably, the content is 33 to 66% by mass. When the content ratio of the acrylic polymer particles A and the acrylic polymer particles B in the binder is in the above range, the binding force is good, and the binder is dispersed without thickening, so the smoothness of the porous film is also improved. Excellent.
　バインダーにおける、アクリル重合体粒子Ｂにおけるエポキシ基に対するアクリル重合体粒子Ａにおけるスルホン酸基の重量比（スルホン酸基／エポキシ基）は、好ましくは０．２～３、より好ましくは０．３～３、特に好ましくは０．３～２である。バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が上記範囲であると、多孔膜スラリーのゲル化を防止し、多孔膜スラリーの塗工性を良好にすることができ、得られる多孔膜の強度が向上する。 The weight ratio of the sulfonic acid groups in the acrylic polymer particles A to the epoxy groups in the acrylic polymer particles B in the binder (sulfonic acid groups / epoxy groups) is preferably 0.2 to 3, more preferably 0.3 to 3. Particularly preferred is 0.3 to 2. When the weight ratio of the sulfonic acid group to the epoxy group in the binder (sulfonic acid group / epoxy group) is within the above range, gelation of the porous film slurry can be prevented, and the coating property of the porous film slurry can be improved. The strength of the obtained porous membrane is improved.
　バインダーの平均粒子径は、好ましくは０．０５～０．５μｍ、より好ましくは０．０７～０．４μｍ、特に好ましくは０．１０～０．２５μｍである。平均粒子径は、レーザー回折で粒度分布を測定することにより求めることができる。バインダーの平均粒子径を上記範囲とすることで、非導電性粒子との結着性が良好になるため、得られる二次電池多孔膜の柔軟性が向上し、二次電池多孔膜から非導電性粒子が脱離（粉落ち）することを防止できる。その結果、該二次電池多孔膜を用いた二次電池は優れた安全性及びサイクル特性を示す。 The average particle size of the binder is preferably 0.05 to 0.5 μm, more preferably 0.07 to 0.4 μm, and particularly preferably 0.10 to 0.25 μm. The average particle size can be determined by measuring the particle size distribution by laser diffraction. By making the average particle diameter of the binder within the above range, the binding property with the non-conductive particles becomes better, so the flexibility of the obtained secondary battery porous film is improved, and the secondary battery porous film is non-conductive. Detachment (powder falling) of the conductive particles can be prevented. As a result, the secondary battery using the secondary battery porous membrane exhibits excellent safety and cycle characteristics.
　多孔膜スラリーの全固形分１００質量％当たりのバインダーの含有割合は、好ましくは０．５～２０質量％、より好ましくは５～２０質量％、特に好ましくは５～１５質量％である。多孔膜スラリーの全固形分１００質量％当たりのバインダーの含有割合を前記範囲にすることにより、非導電性粒子同士の結着力を良好に保つことができ、多孔膜の柔軟性が向上する。また、得られる二次電池のサイクル特性を向上させることができる。 The content ratio of the binder per 100% by mass of the total solid content of the porous membrane slurry is preferably 0.5 to 20% by mass, more preferably 5 to 20% by mass, and particularly preferably 5 to 15% by mass. By making the content rate of the binder per 100% by mass of the total solid content of the porous membrane slurry within the above range, the binding force between the nonconductive particles can be kept good, and the flexibility of the porous membrane is improved. Moreover, the cycle characteristics of the obtained secondary battery can be improved.
（溶媒）
　多孔膜スラリーに用いる溶媒としては、水および有機溶媒のいずれも使用できる。有機溶媒としては、シクロペンタン、シクロヘキサンなどの環状脂肪族炭化水素類；トルエン、キシレン、エチルベンゼンなどの芳香族炭化水素類；アセトン、エチルメチルケトン、ジイソプロピルケトン、シクロヘキサノン、メチルシクロヘキサン、エチルシクロヘキサンなどのケトン類；メチレンクロライド、クロロホルム、四塩化炭素など塩素系脂肪族炭化水素；芳酢酸エチル、酢酸ブチル、γ－ブチロラクトン、ε－カプロラクトンなどのエステル類；アセトニトリル、プロピオニトリルなどのアシロニトリル類；テトラヒドロフラン、エチレングリコールジエチルエーテルなどのエーテル類：メタノール、エタノール、イソプロパノール、エチレングリコール、エチレングリコールモノメチルエーテルなどのアルコール類；Ｎ－メチルピロリドン、Ｎ，Ｎ－ジメチルホルムアミドなどのアミド類があげられる。 (solvent)
As a solvent used for the porous membrane slurry, either water or an organic solvent can be used. Examples of organic solvents include cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as acetone, ethyl methyl ketone, diisopropyl ketone, cyclohexanone, methylcyclohexane, and ethylcyclohexane. Chlorinated aliphatic hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride; Esters such as ethyl acetate, butyl acetate, γ-butyrolactone and ε-caprolactone; Acylonitriles such as acetonitrile and propionitrile; Tetrahydrofuran, Ethers such as ethylene glycol diethyl ether: alcohols such as methanol, ethanol, isopropanol, ethylene glycol and ethylene glycol monomethyl ether; N-methyl Amides such as lupyrrolidone and N, N-dimethylformamide are exemplified.
　これらの溶媒は、単独で使用しても、これらを２種以上混合して混合溶媒として使用してもよい。これらの中でも特に、非導電性粒子の分散性にすぐれ、沸点が低く揮発性の高い溶媒が、短時間でかつ低温で除去できるので好ましい。具体的には、アセトン、トルエン、シクロヘキサノン、シクロペンタン、テトラヒドロフラン、シクロヘキサン、キシレン、水、若しくはＮ－メチルピロリドン、またはこれらの混合溶媒が好ましい。 These solvents may be used alone or as a mixed solvent by mixing two or more of them. Among these, a solvent having excellent dispersibility of non-conductive particles and having a low boiling point and high volatility is preferable because it can be removed in a short time and at a low temperature. Specifically, acetone, toluene, cyclohexanone, cyclopentane, tetrahydrofuran, cyclohexane, xylene, water, N-methylpyrrolidone, or a mixed solvent thereof is preferable.
（任意の成分）
　多孔膜スラリーには、上記成分（非導電性粒子、バインダー及び溶媒）のほかに、さらに任意の成分が含まれていてもよい。かかる任意の成分としては、無機粒子、分散剤、レベリング剤、酸化防止剤、上記バインダー以外の結着剤、増粘剤、消泡剤や、電解液分解抑制等の機能を有する電解液添加剤等の成分を挙げることができる。これらは電池反応に影響を及ぼさないものであれば特に限られない。 (Optional ingredients)
In addition to the above components (nonconductive particles, binder and solvent), the porous membrane slurry may further contain optional components. Examples of such optional components include inorganic particles, dispersants, leveling agents, antioxidants, binders other than the above binders, thickeners, antifoaming agents, and electrolytic solution additives having functions such as suppression of electrolytic solution decomposition. And the like. These are not particularly limited as long as they do not affect the battery reaction.
　無機粒子としては、例えば酸化アルミニウム、酸化珪素、酸化マグネシウム、酸化チタン、窒化アルミニウム、フッ化カルシウム、フッ化バリウムタルク、モンモリロナイトなどの各種無機粒子を使用することができる。特に球状ではない異型粒子が好ましい。多孔膜スラリーの全固形分１００質量％当たりの無機粒子の含有割合は、２０質量％以下、より好ましくは１０質量％以下である。無機粒子の含有割合がこの範囲であると、強度が強く、リチウムイオンの透過性が良好な多孔膜を得ることができる。 As the inorganic particles, for example, various inorganic particles such as aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, aluminum nitride, calcium fluoride, barium fluoride talc, and montmorillonite can be used. In particular, non-spherical atypical particles are preferred. The content ratio of the inorganic particles per 100% by mass of the total solid content of the porous membrane slurry is 20% by mass or less, more preferably 10% by mass or less. When the content ratio of the inorganic particles is within this range, a porous film having high strength and good lithium ion permeability can be obtained.
　分散剤としてはアニオン性化合物、カチオン性化合物、非イオン性化合物、高分子化合物が例示される。分散剤は用いる非導電性粒子に応じて選択される。多孔膜スラリーの全固形分１００質量％当たりの分散剤の含有割合は、電池特性に影響が及ばない範囲が好ましく、具体的には１０質量％以下である。分散剤の含有割合がこの範囲であると、本発明の多孔膜スラリーの塗工性が良好であり、均一な多孔膜を得ることができる。 Examples of the dispersant include anionic compounds, cationic compounds, nonionic compounds, and polymer compounds. A dispersing agent is selected according to the nonelectroconductive particle to be used. The content ratio of the dispersing agent per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less. When the content ratio of the dispersant is within this range, the coating property of the porous membrane slurry of the present invention is good, and a uniform porous membrane can be obtained.
　レベリング剤としてはアルキル系界面活性剤、シリコーン系界面活性剤、フッ素系界面活性剤、金属系界面活性剤などの界面活性剤が挙げられる。多孔膜スラリーの全固形分１００質量％当たりの界面活性剤の含有割合は、電池特性に影響が及ばない範囲が好ましく、具体的には１０質量％以下である。前記界面活性剤を混合することにより、本発明の多孔膜スラリーを所定の基材に塗工する際に発生するはじきを防止し、多孔膜の平滑性を向上させることができる。 Examples of leveling agents include surfactants such as alkyl surfactants, silicone surfactants, fluorine surfactants, and metal surfactants. The content ratio of the surfactant per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less. By mixing the surfactant, repelling that occurs when the porous membrane slurry of the present invention is applied to a predetermined substrate can be prevented, and the smoothness of the porous membrane can be improved.
　酸化防止剤としてはフェノール化合物、ハイドロキノン化合物、有機リン化合物、硫黄化合物、フェニレンジアミン化合物、ポリマー型フェノール化合物等が挙げられる。ポリマー型フェノール化合物は、分子内にフェノール構造を有する重合体であり、重量平均分子量が２００～１０００、好ましくは６００～７００のポリマー型フェノール化合物が好ましく用いられる。多孔膜スラリーの全固形分１００質量％当たりの酸化防止剤の含有割合は、電池特性に影響が及ばない範囲が好ましく、具体的には１０質量％以下である。酸化防止剤の含有割合がこの範囲であると、電池のサイクル寿命が優れる。 Examples of the antioxidant include a phenol compound, a hydroquinone compound, an organic phosphorus compound, a sulfur compound, a phenylenediamine compound, and a polymer type phenol compound. The polymer type phenol compound is a polymer having a phenol structure in the molecule, and a polymer type phenol compound having a weight average molecular weight of 200 to 1000, preferably 600 to 700 is preferably used. The content ratio of the antioxidant per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less. When the content ratio of the antioxidant is within this range, the cycle life of the battery is excellent.
　上記バインダー以外の結着剤としては、後述の電極用結着剤に使用されるポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリアクリル酸誘導体、ポリアクリロニトリル誘導体、軟質重合体などを用いることができる。多孔膜スラリーの全固形分１００質量％当たりの上記バインダー以外の結着剤の含有割合は、１０質量％以下である。結着剤の含有割合がこの範囲であると、本発明の多孔膜と後述する電極活物質層や有機セパレーターとの密着性が良好である。 Examples of binders other than the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyacrylic acid derivatives, polyacrylonitrile derivatives, and soft polymers used in electrode binders described later. Can be used. The content rate of binder other than the said binder per 100 mass% of total solid content of a porous membrane slurry is 10 mass% or less. When the content ratio of the binder is within this range, the adhesion between the porous film of the present invention and the electrode active material layer and organic separator described later is good.
　増粘剤としては、カルボキシメチルセルロース、メチルセルロース、ヒドロキシプロピルセルロースなどのセルロース系ポリマーおよびこれらのアンモニウム塩並びにアルカリ金属塩；（変性）ポリ（メタ）アクリル酸およびこれらのアンモニウム塩並びにアルカリ金属塩；（変性）ポリビニルアルコール、アクリル酸又はアクリル酸塩とビニルアルコールの共重合体、無水マレイン酸又はマレイン酸もしくはフマル酸とビニルアルコールの共重合体などのポリビニルアルコール類；ポリエチレングリコール、ポリエチレンオキシド、ポリビニルピロリドン、変性ポリアクリル酸、酸化スターチ、リン酸スターチ、カゼイン、各種変性デンプン、アクリロニトリル－ブタジエン共重合体水素化物などが挙げられる。多孔膜スラリーの全固形分１００質量％当たりの増粘剤の含有割合は、電池特性に影響が及ばない範囲が好ましく、具体的には１０質量％以下である。増粘剤の含有割合がこの範囲であると、本発明の多孔膜スラリーの塗工性や、本発明の多孔膜と後述する電極活物質層や有機セパレーターとの密着性が良好である。本発明において、「（変性）ポリ」は「未変性ポリ」又は「変性ポリ」を意味し、「（メタ）アクリル」は、「アクリル」又は「メタアクリル」を意味する。 Examples of thickeners include cellulosic polymers such as carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, and ammonium salts and alkali metal salts thereof; (modified) poly (meth) acrylic acid and ammonium salts and alkali metal salts thereof; ) Polyvinyl alcohols such as polyvinyl alcohol, copolymers of acrylic acid or acrylate and vinyl alcohol, maleic anhydride or copolymers of maleic acid or fumaric acid and vinyl alcohol; polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, modified Examples thereof include polyacrylic acid, oxidized starch, phosphoric acid starch, casein, various modified starches, acrylonitrile-butadiene copolymer hydride, and the like. The content ratio of the thickener per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less. When the content of the thickener is within this range, the coating property of the porous membrane slurry of the present invention and the adhesion between the porous membrane of the present invention and the electrode active material layer and organic separator described later are good. In the present invention, “(modified) poly” means “unmodified poly” or “modified poly”, and “(meth) acryl” means “acryl” or “methacryl”.
　消泡剤としては、金属石鹸類、ポリシロキサン類、ポリエーテル類、高級アルコール類、パーフルオロアルキル類などが用いられる。多孔膜スラリーの全固形分１００質量％当たりの消泡剤の含有割合は、電池特性に影響が及ばない範囲が好ましく、具体的には１０質量％以下である。消泡剤を混合することにより、バインダーの消泡工程を短縮することができる。 As the antifoaming agent, metal soaps, polysiloxanes, polyethers, higher alcohols, perfluoroalkyls and the like are used. The content ratio of the antifoaming agent per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less. By mixing an antifoaming agent, the defoaming step of the binder can be shortened.
　電解液添加剤は、後述する電極用スラリー中及び電解液中に使用されるビニレンカーボネートなどを用いることができる。多孔膜スラリーの全固形分１００質量％当たりの電解液添加剤の含有割合は、電池特性に影響が及ばない範囲が好ましく、具体的には１０質量％以下である。電解液添加剤を混合することにより、電池のサイクル寿命が優れる。 As the electrolytic solution additive, vinylene carbonate used in an electrode slurry and an electrolytic solution described later can be used. The content ratio of the electrolytic solution additive per 100% by mass of the total solid content of the porous membrane slurry is preferably within a range that does not affect the battery characteristics, and specifically 10% by mass or less. By mixing the electrolyte additive, the cycle life of the battery is excellent.
　その他には、フュームドシリカやフュームドアルミナなどのナノ微粒子が挙げられる。前記ナノ微粒子を混合することにより多孔膜スラリーのチキソ性をコントロールすることができ、さらにそれにより得られる多孔膜のレベリング性を向上させることができる。 Other examples include nanoparticles such as fumed silica and fumed alumina. By mixing the nano fine particles, the thixotropy of the porous membrane slurry can be controlled, and the leveling properties of the porous membrane obtained thereby can be improved.
　多孔膜スラリーの全固形分１００質量％当たりの上記任意の成分の含有割合の合計は、好ましくは４０質量％以下、より好ましくは２０質量％以下である。ただし、上記非導電性粒子、バインダー、及び任意の成分（但し無機粒子、結着剤を除く）の合計が１００質量％に満たない場合は、任意成分としての結着剤の含有割合を適宜増量し、組成物を得ることができる。 The total content of the above-mentioned arbitrary components per 100% by mass of the total solid content of the porous membrane slurry is preferably 40% by mass or less, more preferably 20% by mass or less. However, if the total of the non-conductive particles, binder, and optional components (excluding inorganic particles and binder) is less than 100% by mass, the content of the binder as an optional component is increased appropriately. And a composition can be obtained.
　多孔膜スラリーの固形分濃度は、該スラリーの塗布、浸漬が可能な程度でかつ、流動性を有する粘度になる限り特に限定はされないが、一般的には１０～５０質量％程度である。 The solid content concentration of the porous membrane slurry is not particularly limited as long as the slurry can be applied and immersed and has a fluid viscosity, but is generally about 10 to 50% by mass.
　固形分以外の成分は、乾燥の工程により揮発する成分であり、前記溶媒に加え、例えば、非導電性粒子及びバインダーの調製及び添加に際しこれらを溶解または分散させていた媒質をも含む。 Components other than the solid content are components that volatilize in the drying step, and include, in addition to the solvent, for example, a medium in which these are dissolved or dispersed during preparation and addition of non-conductive particles and a binder.
　二次電池多孔膜スラリーの製造方法は、特に限定はされず、上記の非導電性粒子、バインダー、溶媒及び必要に応じ添加される任意の成分を混合することにより製造される。本発明においては上記成分（非導電性粒子、バインダー、溶媒及び必要に応じ添加される任意の成分）を用いることにより混合方法や混合順序にかかわらず、非導電性粒子が高度に分散された多孔膜スラリーを得ることができる。混合装置は、上述したバインダーの製造に用いる混合装置と同様の混合装置を使用することができる。中でも高い分散シェアを加えることができる、ビーズミル、ロールミル、フィルミックス等の高分散装置を使用することが特に好ましい。 The production method of the secondary battery porous membrane slurry is not particularly limited, and is produced by mixing the non-conductive particles, the binder, the solvent, and optional components added as necessary. In the present invention, by using the above components (non-conductive particles, binder, solvent, and optional components added as necessary), the non-conductive particles are highly dispersed regardless of the mixing method and mixing order. A membrane slurry can be obtained. As the mixing apparatus, a mixing apparatus similar to the mixing apparatus used for the production of the binder described above can be used. Among them, it is particularly preferable to use a high dispersion apparatus such as a bead mill, a roll mill, or a fill mix that can add a high dispersion share.
　多孔膜スラリーの粘度は、均一塗工性、スラリー経時安定性の観点から、好ましくは１０～１０，０００ｍＰａ・ｓ、更に好ましくは５０～５００ｍＰａ・ｓである。前記粘度は、Ｂ型粘度計を用いて２５℃、回転数６０ｒｐｍで測定した時の値である。 The viscosity of the porous membrane slurry is preferably 10 to 10,000 mPa · s, more preferably 50 to 500 mPa · s, from the viewpoints of uniform coatability and slurry aging stability. The viscosity is a value measured using a B-type viscometer at 25 ° C. and a rotation speed of 60 rpm.
（２）二次電池多孔膜
　本発明の二次電池多孔膜（以下、「多孔膜」と表すことがある。）は、上述した二次電池多孔膜スラリーを膜状に形成、乾燥してなる。
　多孔膜は、有機セパレーターや電極に積層して用いたり、有機セパレーターそのものとして用いたりする。 (2) Secondary Battery Porous Membrane The secondary battery porous membrane of the present invention (hereinafter sometimes referred to as “porous membrane”) is formed by forming the above-described secondary battery porous membrane slurry into a film and drying it. .
The porous film is used by being laminated on an organic separator or an electrode, or used as an organic separator itself.
＜二次電池多孔膜の製造方法＞
　本発明の多孔膜を製造する方法としては、（Ｉ）上記の非導電性粒子、バインダー、溶媒及び任意の成分を含む多孔膜スラリーを所定の基材（正極、負極または有機セパレーター）上に塗布し、次いで乾燥する方法；（ＩＩ）上記の非導電性粒子、バインダー、溶媒及び任意の成分を含む多孔膜スラリーを基材（正極、負極または有機セパレーター）に浸漬後、これを乾燥する方法；（ＩＩＩ）上記の非導電性粒子、バインダー、溶媒及び任意の成分を含む多孔膜スラリーを、剥離フィルム上に塗布、成膜し、得られた多孔膜を所定の基材（正極、負極または有機セパレーター）上に転写する方法；が挙げられる。この中でも、（Ｉ）多孔膜スラリーを基材（正極、負極または有機セパレーター）に塗布し、次いで乾燥する方法が、多孔膜の膜厚を制御しやすいことから最も好ましい。 <Method for producing secondary battery porous membrane>
As a method for producing a porous film of the present invention, (I) a porous film slurry containing the above non-conductive particles, a binder, a solvent and an optional component is applied on a predetermined substrate (positive electrode, negative electrode or organic separator). (II) A method of drying the porous film slurry containing the above non-conductive particles, a binder, a solvent and an optional component after immersing the substrate in a substrate (positive electrode, negative electrode or organic separator); (III) A porous film slurry containing the above non-conductive particles, binder, solvent and optional components is applied and formed on a release film, and the resulting porous film is formed into a predetermined substrate (positive electrode, negative electrode or organic) And a method of transferring onto the separator). Among these, (I) The method of applying the porous film slurry to the substrate (positive electrode, negative electrode or organic separator) and then drying is most preferable because the film thickness of the porous film can be easily controlled.
　本発明の多孔膜は、上述の（Ｉ）～（ＩＩＩ）の方法で製造されるが、その詳細な製造方法を以下に説明する。
　（Ｉ）の方法では、多孔膜スラリーを、所定の基材（正極、負極または有機セパレーター）上に塗布し、乾燥することで本発明の多孔膜は製造される。 The porous membrane of the present invention is manufactured by the above-described methods (I) to (III), and the detailed manufacturing method will be described below.
In the method (I), the porous membrane slurry of the present invention is produced by applying a porous membrane slurry onto a predetermined substrate (positive electrode, negative electrode or organic separator) and drying.
　該スラリーを基材上に塗布する方法は特に制限されず、例えば、ドクターブレード法、リバースロール法、ダイレクトロール法、グラビア法、エクストルージョン法、ハケ塗り法などの方法が挙げられる。中でも、均一な多孔膜が得られる点でグラビア法が好ましい。 The method for applying the slurry onto the substrate is not particularly limited, and examples thereof include a doctor blade method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method. Among these, the gravure method is preferable in that a uniform porous film can be obtained.
　乾燥方法としては例えば温風、熱風、低湿風による乾燥、真空乾燥、（遠）赤外線や電子線などの照射による乾燥法が挙げられる。乾燥温度は、使用する溶媒の種類によって変えることができる。溶媒を完全に除去するために、例えば、Ｎ－メチルピロリドン等の揮発性の低い溶媒を用いる場合には送風式の乾燥機で１２０℃以上の高温で乾燥させることが好ましい。逆に揮発性の高い溶媒を用いる場合には１００℃以下の低温において乾燥させることもできる。多孔膜を後述する有機セパレーター上に形成する際は、有機セパレーターの収縮を起こさずに乾燥させることが必要の為、１００℃以下の低温での乾燥が好ましい。 Examples of the drying method include drying with warm air, hot air, low-humidity air, vacuum drying, and drying by irradiation with (far) infrared rays or electron beams. The drying temperature can vary depending on the type of solvent used. In order to completely remove the solvent, for example, when a low-volatility solvent such as N-methylpyrrolidone is used, it is preferably dried at a high temperature of 120 ° C. or higher with a blower-type dryer. Conversely, when a highly volatile solvent is used, it can be dried at a low temperature of 100 ° C. or lower. When forming a porous film on the organic separator mentioned later, since it is necessary to dry without causing shrinkage of the organic separator, drying at a low temperature of 100 ° C. or lower is preferable.
　（ＩＩ）の方法では、多孔膜スラリーを基材（正極、負極または有機セパレーター）に浸漬し、乾燥することで本発明の多孔膜は製造される。該スラリーを基材に浸漬する方法は特に制限されず、例えば、ディップコーター等でディップコーティングすることで浸漬することができる。
　乾燥方法としては、上述の（Ｉ）の方法での乾燥方法と同じ方法が挙げられる。 In the method (II), the porous membrane of the present invention is produced by immersing the porous membrane slurry in a substrate (positive electrode, negative electrode or organic separator) and drying. The method for immersing the slurry in the substrate is not particularly limited, and for example, the slurry can be immersed by dip coating with a dip coater or the like.
Examples of the drying method include the same methods as the drying method in the method (I) described above.
　（ＩＩＩ）の方法では、多孔膜スラリーを剥離フィルム上に塗布、成膜し、剥離フィルム上に形成された多孔膜を製造する。次いで、得られた多孔膜は基材（正極、負極または有機セパレーター）上に転写される。
　塗布方法としては、上述の（Ｉ）の方法での塗布方法と同じ方法が挙げられる。転写方法は特に限定されない。 In the method (III), a porous film slurry is applied on a release film and formed into a film, thereby producing a porous film formed on the release film. Next, the obtained porous film is transferred onto a substrate (positive electrode, negative electrode or organic separator).
As a coating method, the same method as the coating method in the above-mentioned method (I) can be mentioned. The transfer method is not particularly limited.
　（Ｉ）～（ＩＩＩ）の方法で得られた多孔膜は、次いで、必要に応じ、金型プレスやロールプレスなどを用い、加圧処理により基材（正極、負極または有機セパレーター）と多孔膜との密着性を向上させることもできる。ただし、この際、過度に加圧処理を行うと、多孔膜の空隙率が損なわれることがあるため、圧力および加圧時間を適宜に制御する。 The porous film obtained by the methods (I) to (III) is then subjected to pressure treatment using a die press or a roll press, if necessary, and a substrate (positive electrode, negative electrode or organic separator) and porous film. It is also possible to improve the adhesion. However, at this time, if the pressure treatment is excessively performed, the porosity of the porous film may be impaired, so the pressure and the pressure time are controlled appropriately.
　多孔膜の膜厚は、特に限定はされず、多孔膜の用途あるいは適用分野に応じて適宜に設定されるが、薄すぎると均一な膜を形成できず、逆に厚すぎると電池内での体積（重量）あたりの容量（ｃａｐａｃｉｔｙ）が減ることから、０．５～５０μｍが好ましく、０．５～１０μｍがより好ましい。 The film thickness of the porous film is not particularly limited and is appropriately set according to the use or application field of the porous film. However, if the film is too thin, a uniform film cannot be formed. Since the capacity per volume (weight) decreases, 0.5 to 50 μm is preferable, and 0.5 to 10 μm is more preferable.
　本発明の多孔膜は、基材（正極、負極または有機セパレーター）の表面に成膜され、後述する電極活物質層の保護膜あるいはセパレーターとして特に好ましく用いられる。本発明の多孔膜は、二次電池の正極、負極または有機セパレーターの何れの表面に成膜されてもよく、正極、負極および有機セパレーターの全てに成膜されてもよい。 The porous film of the present invention is formed on the surface of a substrate (positive electrode, negative electrode or organic separator) and is particularly preferably used as a protective film or separator for an electrode active material layer described later. The porous film of the present invention may be formed on any surface of the positive electrode, negative electrode or organic separator of the secondary battery, or may be formed on all of the positive electrode, negative electrode and organic separator.
（３）二次電池電極
　二次電池としては、リチウムイオン二次電池やニッケル水素二次電池等が挙げられる。この中でも、安全性向上が最も求められており多孔膜導入効果が最も高いことからリチウムイオン二次電池が好ましいため、以下においては、リチウムイオン二次電池に使用する場合について説明する。
　本発明の二次電池電極は、集電体、該集電体に付着してなる、電極活物質及び結着剤を含んでなる電極活物質層、及び、該電極活物質層の表面に積層された上述の二次電池多孔膜を含んでなる。つまり、本発明の二次電池電極は、電極活物質及び電極用結着剤を含む電極活物質層が集電体に付着し、かつ、電極活物質層の表面に、上述の二次電池多孔膜が積層されてなる。 (3) Secondary battery electrode Examples of the secondary battery include a lithium ion secondary battery and a nickel metal hydride secondary battery. Among these, since the lithium ion secondary battery is preferable because safety improvement is most demanded and the effect of introducing the porous film is the highest, a case where it is used for a lithium ion secondary battery will be described below.
The secondary battery electrode of the present invention includes a current collector, an electrode active material layer comprising an electrode active material and a binder, which is attached to the current collector, and a laminate on the surface of the electrode active material layer. The above-described secondary battery porous membrane. That is, in the secondary battery electrode of the present invention, the electrode active material layer containing the electrode active material and the electrode binder is attached to the current collector, and the surface of the electrode active material layer has the above-mentioned secondary battery porosity. A film is laminated.
（電極活物質）
　リチウムイオン二次電池用電極に用いられる電極活物質は、電解質中で電位をかける事により可逆的にリチウムイオンを挿入放出できるものであればよく、無機化合物でも有機化合物でも用いることができる。 (Electrode active material)
The electrode active material used for the electrode for the lithium ion secondary battery is not particularly limited as long as it can reversibly insert and release lithium ions by applying a potential in the electrolyte, and can be an inorganic compound or an organic compound.
　リチウムイオン二次電池正極用の電極活物質（正極活物質）は、無機化合物からなるものと有機化合物からなるものとに大別される。無機化合物からなる正極活物質としては、遷移金属酸化物、リチウムと遷移金属との複合酸化物、遷移金属硫化物などが挙げられる。上記の遷移金属としては、Ｆｅ、Ｃｏ、Ｎｉ、Ｍｎ等が使用される。正極活物質に使用される無機化合物の具体例としては、ＬｉＣｏＯ２、ＬｉＮｉＯ２、ＬｉＭｎＯ２、ＬｉＭｎ２Ｏ４、ＬｉＦｅＰＯ４、ＬｉＦｅＶＯ４などのリチウム含有複合金属酸化物；ＴｉＳ２、ＴｉＳ３、非晶質ＭｏＳ２等の遷移金属硫化物；Ｃｕ２Ｖ２Ｏ３、非晶質Ｖ２Ｏ－Ｐ２Ｏ５、ＭｏＯ３、Ｖ２Ｏ５、Ｖ６Ｏ１３などの遷移金属酸化物が挙げられる。これらの化合物は、部分的に元素置換したものであってもよい。有機化合物からなる正極活物質としては、例えば、ポリアセチレン、ポリ－ｐ－フェニレンなどの導電性高分子を用いることもできる。電気伝導性に乏しい、鉄系酸化物は、還元焼成時に炭素源物質を存在させることで、炭素材料で覆われた電極活物質として用いてもよい。また、これら化合物は、部分的に元素置換したものであってもよい。 Electrode active materials (positive electrode active materials) for lithium ion secondary battery positive electrodes are broadly classified into those made of inorganic compounds and those made of organic compounds. Examples of the positive electrode active material made of an inorganic compound include transition metal oxides, composite oxides of lithium and transition metals, and transition metal sulfides. As the transition metal, Fe, Co, Ni, Mn and the like are used. Specific examples of the inorganic compound used for the positive electrode active material include LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiFePO 4 , LiFeVO 4, and other lithium-containing composite metal oxides; TiS 2 , TiS 3 , non- Transition metal sulfides such as crystalline MoS 2 ; transition metal oxides such as Cu 2 V 2 O 3 , amorphous V 2 O—P 2 O 5 , MoO 3 , V 2 O 5 , V 6 O 13 It is done. These compounds may be partially element-substituted. As the positive electrode active material made of an organic compound, for example, a conductive polymer such as polyacetylene or poly-p-phenylene can be used. An iron-based oxide having poor electrical conductivity may be used as an electrode active material covered with a carbon material by allowing a carbon source material to be present during reduction firing. These compounds may be partially element-substituted.
　リチウムイオン二次電池用の正極活物質は、上記の無機化合物と有機化合物の混合物であってもよい。正極活物質の粒子径は、電池の任意の構成要件との兼ね合いで適宜選択されるが、レート特性、サイクル特性などの電池特性の向上の観点から、５０％体積累積径が、通常０．１～５０μｍ、好ましくは１～２０μｍである。５０％体積累積径がこの範囲であると、充放電容量が大きい二次電池を得ることができ、かつ電極用スラリーおよび電極を製造する際の取扱いが容易である。５０％体積累積径は、レーザー回折で粒度分布を測定することにより求めることができる。 The positive electrode active material for a lithium ion secondary battery may be a mixture of the above inorganic compound and organic compound. The particle diameter of the positive electrode active material is appropriately selected in consideration of the arbitrary constituent requirements of the battery. From the viewpoint of improving battery characteristics such as rate characteristics and cycle characteristics, the 50% volume cumulative diameter is usually 0.1. It is ˜50 μm, preferably 1 to 20 μm. When the 50% volume cumulative diameter is within this range, a secondary battery having a large charge / discharge capacity can be obtained, and handling of the slurry for electrodes and the electrodes is easy. The 50% volume cumulative diameter can be determined by measuring the particle size distribution by laser diffraction.
　リチウムイオン二次電池負極用の電極活物質（負極活物質）としては、たとえば、アモルファスカーボン、グラファイト、天然黒鉛、メゾカーボンマイクロビーズ、ピッチ系炭素繊維などの炭素質材料、ポリアセン等の導電性高分子化合物などがあげられる。また、負極活物質としては、ケイ素、錫、亜鉛、マンガン、鉄、ニッケル等の金属やこれらの合金、前記金属又は合金の酸化物や硫酸塩が用いられる。加えて、金属リチウム、Ｌｉ－Ａｌ、Ｌｉ－Ｂｉ－Ｃｄ、Ｌｉ－Ｓｎ－Ｃｄ等のリチウム合金、リチウム遷移金属窒化物、シリコーン等を使用できる。電極活物質は、機械的改質法により表面に導電付与材を付着させたものも使用できる。負極活物質の粒子径は、電池の他の構成要件との兼ね合いで適宜選択されるが、初期効率、レート特性、サイクル特性などの電池特性の向上の観点から、５０％体積累積径が、通常１～５０μｍ、好ましくは１５～３０μｍである。 Examples of electrode active materials (negative electrode active materials) for negative electrodes of lithium ion secondary batteries include carbonaceous materials such as amorphous carbon, graphite, natural graphite, mesocarbon microbeads, pitch-based carbon fibers, and high conductivity such as polyacene. Molecular compounds and the like. In addition, as the negative electrode active material, metals such as silicon, tin, zinc, manganese, iron, nickel, alloys thereof, oxides or sulfates of the metals or alloys are used. In addition, lithium alloys such as lithium metal, Li—Al, Li—Bi—Cd, and Li—Sn—Cd, lithium transition metal nitride, silicone, and the like can be used. As the electrode active material, a material obtained by attaching a conductivity imparting material to the surface by a mechanical modification method can be used. The particle size of the negative electrode active material is appropriately selected in consideration of the other structural requirements of the battery. From the viewpoint of improving battery characteristics such as initial efficiency, rate characteristics, and cycle characteristics, a 50% volume cumulative diameter is usually The thickness is 1 to 50 μm, preferably 15 to 30 μm.
（電極用結着剤）
　本発明において、電極活物質層は電極活物質の他に、結着剤（以下、「電極用結着剤」と記載することがある。）を含む。電極用結着剤を含むことにより電極中の電極活物質層の結着性が向上し、電極の捲回時等の工程上においてかかる機械的な力に対する強度が上がり、また電極中の電極活物質層が脱離しにくくなることから、脱離物による短絡等の危険性が小さくなる。 (Binder for electrode)
In the present invention, the electrode active material layer includes a binder (hereinafter sometimes referred to as “electrode binder”) in addition to the electrode active material. By including the binder for the electrode, the binding property of the electrode active material layer in the electrode is improved, the strength against the mechanical force applied during the process of winding the electrode is increased, and the electrode active material in the electrode is increased. Since the material layer is less likely to be detached, the risk of a short circuit due to the desorbed material is reduced.
　電極用結着剤としては様々な樹脂成分を用いることができる。例えば、ポリエチレン、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）、テトラフルオロエチレン－ヘキサフルオロプロピレン共重合体（ＦＥＰ）、ポリアクリル酸誘導体、ポリアクリロニトリル誘導体などを用いることができる。これらは単独で用いてもよく、２種以上を組み合わせて用いてもよい。また、本発明の多孔膜に用いるバインダーを電極用結着剤として用いることもできる。 Various resin components can be used as the electrode binder. For example, polyethylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyacrylic acid derivatives, polyacrylonitrile derivatives, and the like can be used. These may be used alone or in combination of two or more. Moreover, the binder used for the porous film of this invention can also be used as a binder for electrodes.
　更に、下に例示する軟質重合体も電極用結着剤として使用することができる。
　ポリブチルアクリレート、ポリブチルメタクリレート、ポリヒドロキシエチルメタクリレート、ポリアクリルアミド、ポリアクリロニトリル、ブチルアクリレート・スチレン共重合体、ブチルアクリレート・アクリロニトリル共重合体、ブチルアクリレート・アクリロニトリル・グリシジルメタクリレート共重合体などの、アクリル酸またはメタクリル酸誘導体の単独重合体またはそれと共重合可能なモノマーとの共重合体である、アクリル系軟質重合体；
　ポリイソブチレン、イソブチレン・イソプレンゴム、イソブチレン・スチレン共重合体などのイソブチレン系軟質重合体；
　ポリブタジエン、ポリイソプレン、ブタジエン・スチレンランダム共重合体、イソプレン・スチレンランダム共重合体、アクリロニトリル・ブタジエン共重合体、アクリロニトリル・ブタジエン・スチレン共重合体、ブタジエン・スチレン・ブロック共重合体、スチレン・ブタジエン・スチレン・ブロック共重合体、イソプレン・スチレン・ブロック共重合体、スチレン・イソプレン・スチレン・ブロック共重合体などジエン系軟質重合体；
　ジメチルポリシロキサン、ジフェニルポリシロキサン、ジヒドロキシポリシロキサンなどのケイ素含有軟質重合体；
　液状ポリエチレン、ポリプロピレン、ポリ－１－ブテン、エチレン・α－オレフィン共重合体、プロピレン・α－オレフィン共重合体、エチレン・プロピレン・ジエン共重合体（ＥＰＤＭ）、エチレン・プロピレン・スチレン共重合体などのオレフィン系軟質重合体；
　ポリビニルアルコール、ポリ酢酸ビニル、ポリステアリン酸ビニル、酢酸ビニル・スチレン共重合体などビニル系軟質重合体；
　ポリエチレンオキシド、ポリプロピレンオキシド、エピクロルヒドリンゴムなどのエポキシ系軟質重合体；
　フッ化ビニリデン系ゴム、四フッ化エチレン－プロピレンゴムなどのフッ素含有軟質重合体；
　天然ゴム、ポリペプチド、蛋白質、ポリエステル系熱可塑性エラストマー、塩化ビニル系熱可塑性エラストマー、ポリアミド系熱可塑性エラストマーなどのその他の軟質重合体などが挙げられる。これらの軟質重合体は、架橋構造を有したものであってもよく、また、変性により官能基を導入したものであってもよい。 Furthermore, the soft polymer illustrated below can also be used as a binder for electrodes.
Acrylic acid such as polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, butyl acrylate / styrene copolymer, butyl acrylate / acrylonitrile copolymer, butyl acrylate / acrylonitrile / glycidyl methacrylate copolymer Or an acrylic soft polymer, which is a homopolymer of a methacrylic acid derivative or a copolymer with a monomer copolymerizable therewith;
Isobutylene-based soft polymers such as polyisobutylene, isobutylene-isoprene rubber, isobutylene-styrene copolymer;
Polybutadiene, polyisoprene, butadiene / styrene random copolymer, isoprene / styrene random copolymer, acrylonitrile / butadiene copolymer, acrylonitrile / butadiene / styrene copolymer, butadiene / styrene / block copolymer, styrene / butadiene / Diene-based soft polymers such as styrene block copolymer, isoprene / styrene block copolymer, styrene / isoprene / styrene block copolymer;
Silicon-containing soft polymers such as dimethylpolysiloxane, diphenylpolysiloxane, dihydroxypolysiloxane;
Liquid polyethylene, polypropylene, poly-1-butene, ethylene / α-olefin copolymer, propylene / α-olefin copolymer, ethylene / propylene / diene copolymer (EPDM), ethylene / propylene / styrene copolymer, etc. Olefinic soft polymers of
Vinyl-based soft polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, vinyl acetate / styrene copolymer;
Epoxy-based soft polymers such as polyethylene oxide, polypropylene oxide, epichlorohydrin rubber;
Fluorine-containing soft polymers such as vinylidene fluoride rubber and tetrafluoroethylene-propylene rubber;
Examples thereof include other soft polymers such as natural rubber, polypeptide, protein, polyester-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, and polyamide-based thermoplastic elastomer. These soft polymers may have a cross-linked structure or may have a functional group introduced by modification.
　電極活物質層における電極用結着剤の量は、電極活物質１００質量部に対して、好ましくは０．１～５質量部、より好ましくは０．２～４質量部、特に好ましくは０．５～３質量部である。電極活物質層における電極用結着剤量が前記範囲であることにより、電池反応を阻害せずに、電極から活物質が脱離するのを防ぐことができる。 The amount of the electrode binder in the electrode active material layer is preferably from 0.1 to 5 parts by weight, more preferably from 0.2 to 4 parts by weight, particularly preferably from 0.1 to 100 parts by weight of the electrode active material. 5 to 3 parts by mass. When the amount of the electrode binder in the electrode active material layer is within the above range, it is possible to prevent the active material from being detached from the electrode without inhibiting the battery reaction.
　電極用結着剤は、電極を作製するために溶液もしくは分散液として調製される。その時の粘度は、通常１～３００，０００ｍＰａ・ｓの範囲、好ましくは５０～１０，０００ｍＰａ・ｓである。前記粘度は、Ｂ型粘度計を用いて２５℃、回転数６０ｒｐｍで測定した時の値である。 The electrode binder is prepared as a solution or dispersion to produce an electrode. The viscosity at that time is usually in the range of 1 to 300,000 mPa · s, preferably 50 to 10,000 mPa · s. The viscosity is a value measured using a B-type viscometer at 25 ° C. and a rotation speed of 60 rpm.
（任意の添加剤）
　本発明において、電極活物質層には、上記の電極活物質と電極用結着剤の他に、導電性付与材や補強材などの任意の添加剤を含有していてもよい。導電付与材としては、アセチレンブラック、ケッチェンブラック、カーボンブラック、グラファイト、気相成長カーボン繊維、カーボンナノチューブ等の導電性カーボンを使用することができる。黒鉛などの炭素粉末、各種金属のファイバーや箔などが挙げられる。補強材としては、各種の無機および有機の球状、板状、棒状または繊維状のフィラーが使用できる。導電性付与材を用いることにより電極活物質同士の電気的接触を向上させることができ、リチウムイオン二次電池に用いる場合に放電レート特性を改善することができる。導電性付与材や補強材の使用量は、電極活物質１００質量部に対して通常０～２０質量部、好ましくは１～１０質量部である。また、イソチアゾリン系化合物やキレート化合物を、電極活物質層中に含んでもよい。 (Optional additive)
In the present invention, the electrode active material layer may contain an optional additive such as a conductivity-imparting material or a reinforcing material in addition to the electrode active material and the electrode binder. As the conductivity-imparting material, conductive carbon such as acetylene black, ketjen black, carbon black, graphite, vapor-grown carbon fiber, and carbon nanotube can be used. Examples thereof include carbon powders such as graphite, and fibers and foils of various metals. As the reinforcing material, various inorganic and organic spherical, plate-like, rod-like or fibrous fillers can be used. By using the conductivity imparting material, the electrical contact between the electrode active materials can be improved, and the discharge rate characteristics can be improved when used in a lithium ion secondary battery. The amount of the conductivity-imparting material and the reinforcing material used is usually 0 to 20 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the electrode active material. Further, an isothiazoline-based compound or a chelate compound may be included in the electrode active material layer.
　電極活物質層は、電極活物質、電極用結着剤及び溶媒を含むスラリー（以下、「電極用スラリー」と呼ぶことがある。）を集電体に付着させて形成することができる。 The electrode active material layer can be formed by adhering a slurry containing an electrode active material, an electrode binder and a solvent (hereinafter also referred to as “electrode slurry”) to a current collector.
　溶媒としては、電極用結着剤を溶解または粒子状に分散するものであればよいが、溶解するものが好ましい。電極用結着剤を溶解する溶媒を用いると、電極用結着剤が電極活物質や任意の添加剤の表面に吸着することにより、電極活物質などの分散が安定化する。 The solvent is not particularly limited as long as it dissolves or disperses the electrode binder, but preferably dissolves. When a solvent that dissolves the electrode binder is used, the electrode binder is adsorbed on the surface of the electrode active material or any additive, thereby stabilizing the dispersion of the electrode active material.
　電極用スラリーに用いる溶媒としては、水および有機溶媒のいずれも使用できる。有機溶媒としては、シクロペンタン、シクロヘキサンなどの環状脂肪族炭化水素類；トルエン、キシレンなどの芳香族炭化水素類；エチルメチルケトン、シクロヘキサノンなどのケトン類；酢酸エチル、酢酸ブチル、γ－ブチロラクトン、ε－カプロラクトンなどのエステル類；アセトニトリル、プロピオニトリルなどのアシロニトリル類；テトラヒドロフラン、エチレングリコールジエチルエーテルなどのエーテル類；メタノール、エタノール、イソプロパノール、エチレングリコール、エチレングリコールモノメチルエーテルなどのアルコール類；Ｎ－メチルピロリドン、Ｎ，Ｎ－ジメチルホルムアミドなどのアミド類があげられる。これらの溶媒は、単独または２種以上を混合して、乾燥速度や環境上の観点から適宜選択して用いることができる。 As the solvent used for the electrode slurry, either water or an organic solvent can be used. Examples of organic solvents include cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; ketones such as ethyl methyl ketone and cyclohexanone; ethyl acetate, butyl acetate, γ-butyrolactone, ε -Esters such as caprolactone; Acylonitriles such as acetonitrile and propionitrile; Ethers such as tetrahydrofuran and ethylene glycol diethyl ether; Alcohols such as methanol, ethanol, isopropanol, ethylene glycol and ethylene glycol monomethyl ether; N-methyl Amides such as pyrrolidone and N, N-dimethylformamide are exemplified. These solvents may be used alone or in admixture of two or more and appropriately selected from the viewpoint of drying speed and environment.
　電極用スラリーには、さらに増粘剤などの各種の機能を発現する添加剤を含有させることができる。増粘剤としては、電極用スラリーに用いる溶媒に可溶な重合体が用いられる。具体的には、本発明の多孔膜スラリーで例示した増粘剤を用いることができる。増粘剤の使用量は、電極活物質１００質量部に対して、０．５～１．５質量部が好ましい。増粘剤の使用量が前記範囲であると、電極用スラリーの塗工性及び集電体との密着性が良好である。 The electrode slurry may further contain additives that exhibit various functions such as a thickener. As the thickener, a polymer soluble in the solvent used for the electrode slurry is used. Specifically, the thickener exemplified in the porous membrane slurry of the present invention can be used. The amount of the thickener used is preferably 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the electrode active material. When the use amount of the thickener is within the above range, the coating property of the electrode slurry and the adhesion to the current collector are good.
　さらに、電極用スラリーには、上記成分の他に、電池の安定性や寿命を高めるため、トリフルオロプロピレンカーボネート、ビニレンカーボネート、カテコールカーボネート、１，６－ジオキサスピロ［４，４］ノナン－２，７－ジオン、１２－クラウン－４－エーテル等が使用できる。また、これらは後述する電解液に含有せしめて用いてもよい。 Furthermore, in addition to the above components, the electrode slurry contains trifluoropropylene carbonate, vinylene carbonate, catechol carbonate, 1,6-dioxaspiro [4,4] nonane-2,7 in order to increase the stability and life of the battery. -Dione, 12-crown-4-ether and the like can be used. These may be used by being contained in an electrolyte solution described later.
　電極用スラリーにおける溶媒の量は、電極活物質や電極用結着剤などの種類に応じ、塗工に好適な粘度になるように調整して用いる。具体的には、電極用スラリー中の、電極活物質、電極用結着剤および導電性付与材などの任意の添加剤を合わせた固形分の濃度が、好ましくは３０～９０質量％、より好ましくは４０～８０質量％となる量に調整して用いられる。 The amount of the solvent in the electrode slurry is adjusted to a viscosity suitable for coating depending on the type of the electrode active material, the electrode binder, and the like. Specifically, the concentration of solids in the electrode slurry is preferably 30 to 90% by mass, and more preferably combined with any additive such as an electrode active material, an electrode binder, and a conductivity-imparting material. Is used by adjusting the amount to 40 to 80% by mass.
　電極用スラリーは、電極活物質、電極用結着剤、必要に応じて添加される導電性付与材などの任意の添加剤、および溶媒を、混合機を用いて混合して得られる。混合は、上記の各成分を一括して混合機に供給し、混合してもよい。電極用スラリーの構成成分として、電極活物質、電極用結着剤、導電性付与材及び増粘剤を用いる場合には、導電性付与材および増粘剤を溶媒中で混合して導電性付与材を微粒子状に分散させ、次いで電極用結着剤、電極活物質を添加してさらに混合することがスラリーの分散性が向上するので好ましい。混合機としては、ボールミル、サンドミル、顔料分散機、擂潰機、超音波分散機、ホモジナイザー、プラネタリーミキサー、ホバートミキサーなどを用いることができるが、ボールミルを用いると導電性付与材や電極活物質の凝集を抑制できるので好ましい。 The electrode slurry is obtained by mixing an electrode active material, an electrode binder, an optional additive such as a conductivity imparting agent added as necessary, and a solvent using a mixer. Mixing may be performed by supplying the above components all at once to a mixer. When using electrode active materials, electrode binders, conductivity-imparting materials and thickeners as constituents of electrode slurries, conductivity is imparted by mixing the conductivity-imparting materials and thickeners in a solvent. It is preferable to disperse the material in the form of fine particles, and then add a binder for the electrode and an electrode active material and further mix, since the dispersibility of the slurry is improved. As the mixer, a ball mill, sand mill, pigment disperser, crusher, ultrasonic disperser, homogenizer, planetary mixer, Hobart mixer, etc. can be used. It is preferable because aggregation of the resin can be suppressed.
　電極用スラリーの粒度は、好ましくは３５μｍ以下であり、さらに好ましくは２５μｍ以下である。スラリーの粒度が上記範囲にあると、導電性付与材の分散性が高く、均質な電極が得られる。 The particle size of the electrode slurry is preferably 35 μm or less, more preferably 25 μm or less. When the particle size of the slurry is in the above range, the conductivity imparting material is highly dispersible and a homogeneous electrode can be obtained.
（集電体）
　集電体は、電気導電性を有しかつ電気化学的に耐久性のある材料であれば特に制限されないが、耐熱性を有するとの観点から、例えば、鉄、銅、アルミニウム、ニッケル、ステンレス鋼、チタン、タンタル、金、白金などの金属材料が好ましい。中でも、リチウムイオン二次電池の正極用としてはアルミニウムが特に好ましく、リチウムイオン二次電池の負極用としては銅が特に好ましい。集電体の形状は特に制限されないが、厚さ０．００１～０．５ｍｍ程度のシート状のものが好ましい。集電体は、電極活物質層の接着強度を高めるため、予め粗面化処理して使用するのが好ましい。粗面化方法としては、機械的研磨法、電解研磨法、化学研磨法などが挙げられる。機械的研磨法においては、研磨剤粒子を固着した研磨布紙、砥石、エメリバフ、鋼線などを備えたワイヤーブラシ等が使用される。また、電極活物質層の接着強度や導電性を高めるために、集電体表面に中間層を形成してもよい。 (Current collector)
The current collector is not particularly limited as long as it is an electrically conductive and electrochemically durable material. From the viewpoint of having heat resistance, for example, iron, copper, aluminum, nickel, stainless steel, etc. Metal materials such as titanium, tantalum, gold, and platinum are preferable. Among these, aluminum is particularly preferable for the positive electrode of the lithium ion secondary battery, and copper is particularly preferable for the negative electrode of the lithium ion secondary battery. The shape of the current collector is not particularly limited, but a sheet shape having a thickness of about 0.001 to 0.5 mm is preferable. In order to increase the adhesive strength of the electrode active material layer, the current collector is preferably used after roughening in advance. Examples of the roughening method include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method. In the mechanical polishing method, an abrasive cloth paper with a fixed abrasive particle, a grindstone, an emery buff, a wire brush provided with a steel wire or the like is used. Further, an intermediate layer may be formed on the surface of the current collector in order to increase the adhesive strength and conductivity of the electrode active material layer.
　電極活物質層の製造方法は、前記集電体の少なくとも片面、好ましくは両面に電極活物質層を層状に結着させる方法であればよい。例えば、前記電極用スラリーを集電体に塗布、乾燥し、次いで、１２０℃以上で１時間以上加熱処理して電極活物質層を形成する。電極用スラリーを集電体へ塗布する方法は特に制限されない。例えば、ドクターブレード法、ディップ法、リバースロール法、ダイレクトロール法、グラビア法、エクストルージョン法、ハケ塗り法などの方法が挙げられる。乾燥方法としては例えば温風、熱風、低湿風による乾燥、真空乾燥、（遠）赤外線や電子線などの照射による乾燥法が挙げられる。 The method for producing the electrode active material layer may be any method in which the electrode active material layer is bound in layers on at least one surface, preferably both surfaces of the current collector. For example, the electrode slurry is applied to a current collector and dried, and then heat-treated at 120 ° C. or higher for 1 hour or longer to form an electrode active material layer. The method for applying the electrode slurry to the current collector is not particularly limited. Examples thereof include a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method. Examples of the drying method include drying by warm air, hot air, low-humidity air, vacuum drying, and drying by irradiation with (far) infrared rays or electron beams.
　次いで、金型プレスやロールプレスなどを用い、加圧処理により電極活物質層の空隙率を低くすることが好ましい。空隙率の好ましい範囲は５～１５％、より好ましくは７～１３％である。空隙率が高すぎると充電効率や放電効率が悪化する。空隙率が低すぎる場合は、高い体積容量が得難かったり、電極活物質層が剥がれ易く不良を発生し易いといった問題を生じる。さらに、硬化性の重合体を用いる場合は、硬化させることが好ましい。 Next, it is preferable to lower the porosity of the electrode active material layer by pressure treatment using a mold press or a roll press. A preferable range of the porosity is 5 to 15%, more preferably 7 to 13%. If the porosity is too high, charging efficiency and discharging efficiency are deteriorated. When the porosity is too low, there are problems that it is difficult to obtain a high volume capacity, or that the electrode active material layer is easily peeled off and is likely to be defective. Further, when a curable polymer is used, it is preferably cured.
　電極活物質層の厚みは、正極、負極とも、通常５～３００μｍであり、好ましくは１０～２５０μｍである。 The thickness of the electrode active material layer is usually 5 to 300 μm, preferably 10 to 250 μm, for both the positive electrode and the negative electrode.
　本発明の二次電池電極は、電極活物質層が層状に結着した集電体の電極活物質層表面に、本発明の二次電池多孔膜を積層することで製造される。 The secondary battery electrode of the present invention is manufactured by laminating the secondary battery porous film of the present invention on the surface of the electrode active material layer of the current collector in which the electrode active material layer is bound in a layered manner.
　積層方法は特に限定されないが、上述の多孔膜の製造方法で説明した（Ｉ）～（ＩＩＩ）の方法が挙げられる。 The laminating method is not particularly limited, and examples thereof include the methods (I) to (III) described in the above method for producing a porous film.
（４）二次電池セパレーター
　本発明の二次電池セパレーターは、有機セパレーター、該有機セパレーターに積層された上述の二次電池多孔膜を含んでなる。つまり、本発明の二次電池セパレーターは、有機セパレーター上に、上述の二次電池多孔膜が積層されてなる。 (4) Secondary battery separator The secondary battery separator of the present invention comprises an organic separator and the above-described secondary battery porous film laminated on the organic separator. That is, the secondary battery separator of the present invention is formed by laminating the above-described secondary battery porous film on an organic separator.
（有機セパレーター）
　リチウムイオン二次電池用の有機セパレーターとしては、ポリエチレン、ポリプロピレンなどのポリオレフィン樹脂や芳香族ポリアミド樹脂を含んでなるセパレーターなどの公知のものが用いられる。 (Organic separator)
As an organic separator for a lithium ion secondary battery, known ones such as a polyolefin resin such as polyethylene and polypropylene and a separator containing an aromatic polyamide resin are used.
　本発明に用いる有機セパレーターとしては、電子伝導性がなくイオン伝導性があり、有機溶媒の耐性が高い、孔径の微細な多孔質膜が用いられ、例えばポリオレフィン系（ポリエチレン、ポリプロピレン、ポリブテン、ポリ塩化ビニル）、及びこれらの混合物あるいは共重合体等の樹脂からなる微多孔膜、ポリエチレンテレフタレート、ポリシクロオレフィン、ポリエーテルスルフォン、ポリアミド、ポリイミド、ポリイミドアミド、ポリアラミド、ポリシクロオレフィン、ナイロン、ポリテトラフルオロエチレン等の樹脂からなる微多孔膜またはポリオレフィン系の繊維を織ったもの、またはその不織布、絶縁性物質粒子の集合体等が挙げられる。これらの中でも、本発明の多孔膜スラリーの塗工性が優れ、セパレーター全体の膜厚を薄くし電池内の活物質比率を上げて体積あたりの容量を上げることができるため、ポリオレフィン系の樹脂からなる微多孔膜が好ましい。 As the organic separator used in the present invention, a porous membrane having a fine pore size, having no electron conductivity and ionic conductivity and high resistance to organic solvents is used. For example, polyolefin-based (polyethylene, polypropylene, polybutene, polychlorinated) Vinyl), and a microporous film made of a resin such as a mixture or a copolymer thereof, polyethylene terephthalate, polycycloolefin, polyether sulfone, polyamide, polyimide, polyimide amide, polyaramid, polycycloolefin, nylon, polytetrafluoroethylene Examples thereof include a microporous membrane made of a resin such as the above, or a woven fabric of polyolefin fibers, a nonwoven fabric thereof, an aggregate of insulating substance particles, or the like. Among these, since the coating property of the porous membrane slurry of the present invention is excellent, the film thickness of the entire separator can be reduced and the active material ratio in the battery can be increased to increase the capacity per volume. A microporous membrane is preferred.
　有機セパレーターの厚さは、通常０．５～４０μｍ、好ましくは１～３０μｍ、更に好ましくは１～２０μｍである。この範囲であると電池内での有機セパレーターによる抵抗が小さくなる。また、本発明の多孔膜スラリーを有機セパレーターに塗工する際の作業性が良い。 The thickness of the organic separator is usually 0.5 to 40 μm, preferably 1 to 30 μm, more preferably 1 to 20 μm. Within this range, the resistance due to the organic separator in the battery is reduced. Moreover, the workability | operativity at the time of coating the porous membrane slurry of this invention to an organic separator is good.
　本発明において、有機セパレーターの材料として用いるポリオレフィン系の樹脂としては、ポリエチレン、ポリプロピレン等のホモポリマー、コポリマー、更にはこれらの混合物が挙げられる。ポリエチレンとしては、低密度、中密度、高密度のポリエチレンが挙げられ、突き刺し強度や機械的な強度の観点から、高密度のポリエチレンが好ましい。また、これらのポリエチレンは柔軟性を付与する目的から２種以上を混合しても良い。これらポリエチレンに用いる重合触媒も特に制限はなく、チーグラー・ナッタ系触媒やフィリップス系触媒やメタロセン系触媒などが挙げられる。機械強度と高透過性を両立させる観点から、ポリエチレンの粘度平均分子量は１０万～１２００万が好ましく、より好ましくは２０万～３００万である。ポリプロピレンとしては、ホモポリマー、ランダムコポリマー、ブロックコポリマーが挙げられ、一種類または二種類以上を混合して使用することができる。また重合触媒も特に制限はなく、チーグラー・ナッタ系触媒やメタロセン系触媒などが挙げられる。また立体規則性にも特に制限はなく、アイソタクチックやシンジオタクチックやアタクチックを使用することができるが、安価である点からアイソタクチックポリプロピレンを使用するのが望ましい。さらに本発明の効果を損なわない範囲で、ポリオレフィンにはポリエチレン或いはポリプロピレン以外のポリオレフィン及び酸化防止剤、核剤などの添加剤を適量添加してもよい。 In the present invention, examples of the polyolefin-based resin used as the material for the organic separator include homopolymers such as polyethylene and polypropylene, copolymers, and mixtures thereof. Examples of the polyethylene include low density, medium density, and high density polyethylene, and high density polyethylene is preferable from the viewpoint of piercing strength and mechanical strength. These polyethylenes may be mixed in two or more types for the purpose of imparting flexibility. The polymerization catalyst used for these polyethylenes is not particularly limited, and examples thereof include Ziegler-Natta catalysts, Phillips catalysts, and metallocene catalysts. From the viewpoint of achieving both mechanical strength and high permeability, the viscosity average molecular weight of polyethylene is preferably 100,000 to 12 million, and more preferably 200,000 to 3 million. Examples of polypropylene include homopolymers, random copolymers, and block copolymers, and one kind or a mixture of two or more kinds can be used. The polymerization catalyst is not particularly limited, and examples thereof include Ziegler-Natta catalysts and metallocene catalysts. The stereoregularity is not particularly limited, and isotactic, syndiotactic or atactic can be used. However, it is desirable to use isotactic polypropylene because it is inexpensive. Furthermore, an appropriate amount of a polyolefin other than polyethylene or polypropylene, and an additive such as an antioxidant or a nucleating agent may be added to the polyolefin as long as the effects of the present invention are not impaired.
　ポリオレフィン系の有機セパレーターを作製する方法としては、公知公用のものが用いられ、例えば、ポリプロピレン、ポリエチレンを溶融押し出しフィルム製膜した後に、低温でアニーリングさせ結晶ドメインを成長させて、この状態で延伸を行い、非晶領域を延ばす事で微多孔膜を形成する乾式方法；炭化水素溶媒やその他低分子材料とポリプロピレン、ポリエチレンを混合した後に、フィルム形成させて、次いで、非晶相に溶媒や低分子が集まり島相を形成し始めたフィルムを、この溶媒や低分子を他の揮発し易い溶媒を用いて除去する事で微多孔膜が形成される湿式方法；などが選ばれる。この中でも、抵抗を下げる目的で、大きな空隙を得やすい点で、乾式方法が好ましい。 As a method for producing a polyolefin-based organic separator, a publicly known one is used. For example, after forming a melt-extruded film of polypropylene and polyethylene, annealing is performed at a low temperature to grow a crystal domain, and in this state, stretching is performed. A dry method of forming a microporous film by extending the amorphous region; mixing a hydrocarbon solvent or other low molecular weight material with polypropylene or polyethylene, forming a film, and then forming a solvent or low molecular weight into the amorphous phase A wet method in which a microporous film is formed by removing the film that has started to form an island phase by using this solvent or low-molecular solvent with another volatile solvent is selected. Among these, a dry method is preferable in that a large void can be easily obtained for the purpose of reducing the resistance.
　本発明に用いる有機セパレーターは、強度や硬度、熱収縮率を制御する目的で、任意のフィラーや繊維化合物を含んでもよい。また、本発明の多孔膜を積層する場合に、有機セパレーターと多孔膜との密着性を向上させたり、電解液に対する表面張力を下げて液の含浸性を向上させる目的で、あらかじめ低分子化合物や高分子化合物で被覆処理したり、紫外線などの電磁線処理、コロナ放電・プラズマガスなどのプラズマ処理を行ってもよい。
　特に、電解液の含浸性が高く前記多孔膜との密着性を得やすい点から、カルボン酸基、水酸基及びスルホン酸基などの極性基を含有する高分子化合物で被覆処理するのが好ましい。 The organic separator used in the present invention may contain any filler or fiber compound for the purpose of controlling strength, hardness, and heat shrinkage. Further, when laminating the porous membrane of the present invention, a low molecular weight compound or A coating treatment with a polymer compound, an electromagnetic radiation treatment such as ultraviolet rays, or a plasma treatment such as corona discharge / plasma gas may be performed.
In particular, the coating treatment is preferably performed with a polymer compound containing a polar group such as a carboxylic acid group, a hydroxyl group, and a sulfonic acid group from the viewpoint that the impregnation property of the electrolytic solution is high and the adhesion with the porous film is easily obtained.
　本発明の二次電池セパレーターは、上記の有機セパレーター上に、本発明の二次電池多孔膜を積層することで製造される。 The secondary battery separator of the present invention is manufactured by laminating the secondary battery porous film of the present invention on the organic separator.
　積層方法は特に限定されないが、上述の多孔膜の製造方法で説明した（Ｉ）～（ＩＩＩ）の方法が挙げられる。 The laminating method is not particularly limited, and examples thereof include the methods (I) to (III) described in the above method for producing a porous film.
（５）二次電池
　本発明の二次電池は、正極、負極、有機セパレーター及び電解液を含み、正極、負極及び有機セパレーターのいずれかに、上述の多孔膜が積層されてなる。 (5) Secondary Battery The secondary battery of the present invention includes a positive electrode, a negative electrode, an organic separator, and an electrolytic solution, and the above porous film is laminated on any of the positive electrode, the negative electrode, and the organic separator.
（電解液）
　電解液としては、有機溶媒に支持電解質を溶解した有機電解液が用いられる。支持電解質としては、リチウム塩が用いられる。リチウム塩としては、特に制限はないが、ＬｉＰＦ６、ＬｉＡｓＦ６、ＬｉＢＦ４、ＬｉＳｂＦ６、ＬｉＡｌＣｌ４、ＬｉＣｌＯ４、ＣＦ３ＳＯ３Ｌｉ、Ｃ４Ｆ９ＳＯ３Ｌｉ、ＣＦ３ＣＯＯＬｉ、（ＣＦ３ＣＯ）２ＮＬｉ、（ＣＦ３ＳＯ２）２ＮＬｉ、（Ｃ２Ｆ５ＳＯ２）ＮＬｉなどが挙げられる。中でも、溶媒に溶けやすく高い解離度を示すＬｉＰＦ６、ＬｉＣｌＯ４、ＣＦ３ＳＯ３Ｌｉが好ましい。これらは、二種以上を併用してもよい。解離度の高い支持電解質を用いるほどリチウムイオン伝導度が高くなるので、支持電解質の種類によりリチウムイオン伝導度を調節することができる。 (Electrolyte)
As the electrolytic solution, an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is used. A lithium salt is used as the supporting electrolyte. The lithium salt is not particularly limited, LiPF 6, LiAsF 6, LiBF 4, LiSbF 6, LiAlCl 4, LiClO 4, CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) NLi, and the like. Among these, LiPF 6 , LiClO 4 , and CF 3 SO 3 Li that are easily soluble in a solvent and exhibit a high degree of dissociation are preferable. Two or more of these may be used in combination. Since the lithium ion conductivity increases as the supporting electrolyte having a higher degree of dissociation is used, the lithium ion conductivity can be adjusted depending on the type of the supporting electrolyte.
　電解液に使用する有機溶媒としては、支持電解質を溶解できるものであれば特に限定されないが、ジメチルカーボネート（ＤＭＣ）、エチレンカーボネート（ＥＣ）、ジエチルカーボネート（ＤＥＣ）、プロピレンカーボネート（ＰＣ）、ブチレンカーボネート（ＢＣ）、メチルエチルカーボネート（ＭＥＣ）などのカーボネート類；γ－ブチロラクトン、ギ酸メチルなどのエステル類；１，２－ジメトキシエタン、テトラヒドロフランなどのエーテル類；スルホラン、ジメチルスルホキシドなどの含硫黄化合物類；が好適に用いられる。またこれらの溶媒の混合液を用いてもよい。中でも、誘電率が高く、安定な電位領域が広いのでカーボネート類が好ましい。用いる溶媒の粘度が低いほどリチウムイオン伝導度が高くなるので、溶媒の種類によりリチウムイオン伝導度を調節することができる。 The organic solvent used in the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolyte, but dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate. Carbonates such as (BC) and methyl ethyl carbonate (MEC); esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide; Are preferably used. Moreover, you may use the liquid mixture of these solvents. Among these, carbonates are preferable because they have a high dielectric constant and a wide stable potential region. Since the lithium ion conductivity increases as the viscosity of the solvent used decreases, the lithium ion conductivity can be adjusted depending on the type of the solvent.
　電解液中における支持電解質の濃度は、通常１～３０質量％、好ましくは５～２０質量％である。また、支持電解質の種類に応じて、通常０．５～２．５モル／Ｌの濃度で用いられる。支持電解質の濃度が低すぎても高すぎてもイオン導電度は低下する傾向にある。用いる電解液の濃度が低いほど重合体粒子の膨潤度が大きくなるので、電解液の濃度によりリチウムイオン伝導度を調節することができる。 The concentration of the supporting electrolyte in the electrolytic solution is usually 1 to 30% by mass, preferably 5 to 20% by mass. The concentration is usually 0.5 to 2.5 mol / L depending on the type of the supporting electrolyte. If the concentration of the supporting electrolyte is too low or too high, the ionic conductivity tends to decrease. Since the degree of swelling of the polymer particles increases as the concentration of the electrolytic solution used decreases, the lithium ion conductivity can be adjusted by the concentration of the electrolytic solution.
　二次電池の具体的な製造方法としては、正極と負極とを有機セパレーターを介して重ね合わせ、これを電池形状に応じて巻く、折るなどして電池容器に入れ、電池容器に電解液を注入して封口する方法が挙げられる。本発明の多孔膜は、正極、負極、及び有機セパレーターのいずれかに積層される。本発明の多孔膜を、正極、負極、有機セパレーターに積層する方法は、上述した（Ｉ）または（ＩＩ）の方法の通りである。また、上述の（ＩＩＩ）の方法の通り、独立で多孔膜のみを正極、負極または有機セパレーターに積層することも可能である。必要に応じてエキスパンドメタルや、ヒューズ、ＰＴＣ素子などの過電流防止素子、リード板などを入れ、電池内部の圧力上昇、過充放電の防止をする事もできる。電池の形状は、コイン型、ボタン型、シート型、円筒型、角形、扁平型など何れであってもよい。 As a specific method for producing a secondary battery, a positive electrode and a negative electrode are overlapped with an organic separator, and this is wound into a battery container according to the shape of the battery, put into a battery container, and an electrolytic solution is injected into the battery container. And sealing. The porous film of the present invention is laminated on any one of the positive electrode, the negative electrode, and the organic separator. The method of laminating the porous film of the present invention on the positive electrode, the negative electrode, and the organic separator is as described in the method (I) or (II). Moreover, it is also possible to laminate | stack only a porous film on a positive electrode, a negative electrode, or an organic separator independently as the above-mentioned method of (III). If necessary, an expanded metal, an overcurrent prevention element such as a fuse or a PTC element, a lead plate, or the like can be inserted to prevent an increase in pressure inside the battery and overcharge / discharge. The shape of the battery may be any of a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, a flat shape, and the like.
　本発明の二次電池においては、本発明の多孔膜を、正極又は負極の電極活物質層表面に積層することが好ましい。本発明の多孔膜を電極活物質層表面に積層することにより、有機セパレーターが熱による収縮を起こしても、正極・負極間の短絡を起こすことがなく、高い安全性が保たれる。加えて、本発明の多孔膜を電極活物質層表面に積層することにより、有機セパレーターがなくても、多孔膜がセパレーターとしての機能を果たすことができ、低コストで二次電池の作製が可能になる。また、有機セパレーターを用いた場合においても、セパレーター表面に形成されている孔を埋めることがないため、より高いレート特性を発現することができる。 In the secondary battery of the present invention, the porous film of the present invention is preferably laminated on the surface of the electrode active material layer of the positive electrode or the negative electrode. By laminating the porous film of the present invention on the surface of the electrode active material layer, even if the organic separator is contracted by heat, a short circuit between the positive electrode and the negative electrode is not caused, and high safety is maintained. In addition, by laminating the porous membrane of the present invention on the surface of the electrode active material layer, the porous membrane can function as a separator without an organic separator, and a secondary battery can be produced at low cost. become. Further, even when an organic separator is used, higher rate characteristics can be expressed because the holes formed on the separator surface are not filled.
　以下に、実施例を挙げて本発明を説明するが、本発明はこれに限定されるものではない。尚、本実施例における部および％は、特記しない限り質量基準である。実施例および比較例において、各種物性は以下のように評価する。 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. In addition, unless otherwise indicated, the part and% in a present Example are a mass reference | standard. In Examples and Comparative Examples, various physical properties are evaluated as follows.
＜非導電性粒子の耐熱温度（Ｔ１０値）＞
　窒素雰囲気下において、熱天秤により３０℃から昇温速度１０℃／分で加熱し、非導電性粒子の減量割合が１０質量％に達する温度［℃］を求め、耐熱温度とした。 <Heat-resistant temperature of non-conductive particles (T10 value)>
In a nitrogen atmosphere, the mixture was heated from 30 ° C. at a heating rate of 10 ° C./min with a thermobalance, and the temperature [° C.] at which the non-conductive particle weight loss ratio reached 10% by mass was determined as the heat resistant temperature.
＜非導電性粒子の平均粒子径＞
　電子顕微鏡にて２５０００倍の倍率で撮影した写真から１００個の非導電性粒子を任意に選択し、その粒子像の最長辺をａ、最短辺をｂとしたとき、（ａ＋ｂ）／２を粒径とし、１００個の平均から平均粒子径［μｍ］を算出した。 <Average particle size of non-conductive particles>
100 non-conductive particles are arbitrarily selected from a photograph taken with an electron microscope at a magnification of 25000 times, and when the longest side of the particle image is a and the shortest side is b, (a + b) / 2 The average particle diameter [μm] was calculated from the average of 100 particles.
＜非導電性粒子の平均円形度＞
　電子顕微鏡にて２５０００倍の倍率で撮影した写真から１００個の非導電性粒子を任意に選択し、その粒子像と同じ投影面積を持つ円の周囲長をＬ０、粒子像の周囲長をＬとしたとき、Ｌ０／Ｌを円形度とし、１００個の平均から平均円形度を算出した。 <Average circularity of non-conductive particles>
100 non-conductive particles are arbitrarily selected from a photograph taken with an electron microscope at a magnification of 25000 times, the circumference of a circle having the same projected area as the particle image is L 0 , and the circumference of the particle image is L In this case, L 0 / L was defined as the circularity, and the average circularity was calculated from the average of 100 pieces.
＜非導電性粒子の粒子径分布＞
　非導電性粒子の粒子径分布は、ベックマン株式会社製のレーザー回折散乱粒度分布測定装置（LS230）にて粒子径測定を行った後、得られた体積平均粒子径をＶ、数平均粒子径をＮとし、以下の式で求めた。
　粒子径分布＝Ｖ／Ｎ <Particle size distribution of non-conductive particles>
The particle size distribution of the non-conductive particles is determined by measuring the particle size with a laser diffraction scattering particle size distribution measuring device (LS230) manufactured by Beckman Co., Ltd. N was determined by the following formula.
Particle size distribution = V / N
＜多孔膜の均一性＞
　二次電池多孔膜（多孔膜付有機セパレーター）もしくは二次電池電極（多孔膜付電極）を、幅１０ｃｍ×長さ１.５ｍに切り出して、切り出した二次電池多孔膜もしくは二次電池電極の厚みを、株式会社ニコン製の厚さ計（ＭＨ－１５Ｍ）を用いて幅方向３点×長さ方向５ｃｍおきに２０点の６０点において測定し、膜厚の標準偏差と平均値から、下記式に基づき、膜厚のばらつき［％］を計算し、下記の基準で評価した。
Figure JPOXMLDOC01-appb-M000001
 　ここで、ｘは膜厚の平均値、ｎは測定数を示す。
　（評価基準）
　Ａ：２％未満
　Ｂ：２％以上～３％未満
　Ｃ：３％以上～１０％未満
　Ｄ：１０％以上 <Uniformity of porous film>
A secondary battery porous membrane (organic separator with a porous membrane) or a secondary battery electrode (electrode with a porous membrane) is cut into a width of 10 cm and a length of 1.5 m, and the cut secondary battery porous membrane or secondary battery electrode The thickness was measured at 60 points of 20 points every 3 cm in the width direction and every 5 cm in the length direction using a thickness meter (MH-15M) manufactured by Nikon Corporation. From the standard deviation and average value of the film thickness, Based on the formula, film thickness variation [%] was calculated and evaluated according to the following criteria.
Figure JPOXMLDOC01-appb-M000001
 Here, x represents an average value of the film thickness, and n represents the number of measurements.
(Evaluation criteria)
A: Less than 2% B: 2% to less than 3% C: 3% to less than 10% D: 10% or more
　＜二次電池セパレーター（多孔膜付有機セパレーター）の信頼性試験＞
　二次電池セパレーター（多孔膜付有機セパレーター）を直径１９ｍｍの円形に打ち抜き、非イオン性界面活性剤（花王社製；エマルゲン２１０Ｐ）の３重量％メタノール溶液中に浸漬して風乾した。この円形の二次電池セパレーターに電解液を含浸させ、一対の円形のＳＵＳ板（直径１５．５ｍｍ）に挟み、（ＳＵＳ板）／（円形の二次電池セパレーター）／（ＳＵＳ板）という構成に重ね合わせた。ここで電解液はエチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）とをＥＣ：ＤＥＣ＝１：２（２０℃での容積比）で混合してなる混合溶媒にＬｉＰＦ６を１モル／リットルの濃度で溶解させた溶液を用いた。これを２０３２型コインセルに封入した。コインセルからリード線をとり、熱電対を付けてオーブンの中に入れた。振幅１０ｍＶ、１ｋＨｚの周波数の交流を印加しながら、昇温速度１．６℃／分で２００℃まで昇温させ、この間のセル抵抗を測定することで短絡の発生状況を確認した。本試験では温度上昇と共にシャットダウンにより抵抗値が上昇し、少なくとも１０００Ω／ｃｍ２以上になる。その後、１０Ω／ｃｍ２以下まで急激に低下した場合に短絡が発生したものとした。尚、この試験を２０回行ない、評価は下記の基準で評価した。
　（評価基準）
　Ａ：短絡発生数０個
　Ｂ：短絡発生数１個
　Ｃ：短絡発生数２～３個
　Ｄ：短絡発生数４個以上 <Reliability test of secondary battery separator (organic separator with porous membrane)>
A secondary battery separator (organic separator with a porous film) was punched into a circle having a diameter of 19 mm, immersed in a 3 wt% methanol solution of a nonionic surfactant (manufactured by Kao Corporation; Emulgen 210P), and air-dried. This circular secondary battery separator is impregnated with an electrolyte and sandwiched between a pair of circular SUS plates (diameter 15.5 mm), and the structure is (SUS plate) / (circular secondary battery separator) / (SUS plate). Superimposed. Here, the electrolytic solution is a mixed solvent obtained by mixing ethylene carbonate (EC) and diethyl carbonate (DEC) at EC: DEC = 1: 2 (volume ratio at 20 ° C.). The concentration of LiPF 6 is 1 mol / liter. The solution dissolved in was used. This was enclosed in a 2032 type coin cell. I took the lead from the coin cell, put a thermocouple, and put it in the oven. While applying an alternating current with an amplitude of 10 mV and a frequency of 1 kHz, the temperature was raised to 200 ° C. at a temperature rising rate of 1.6 ° C./min, and the cell resistance during this time was measured to confirm the occurrence of a short circuit. In this test, the resistance value increases due to shutdown with a temperature rise and becomes at least 1000 Ω / cm 2 or more. Thereafter, it was assumed that a short circuit occurred when the voltage dropped rapidly to 10 Ω / cm 2 or less. In addition, this test was performed 20 times and evaluation was performed according to the following criteria.
(Evaluation criteria)
A: Number of short-circuit occurrences 0 B: Number of short-circuit occurrences 1 C: Number of short-circuit occurrences 2 to 3 D: Number of short-circuit occurrences 4 or more
＜二次電池電極（多孔膜付電極）の信頼性試験＞
　有機セパレーター（単層のポリプロピレン製セパレーター、気孔率５５％、厚さ２５μｍ）を直径１９ｍｍの円形に打ち抜き、非イオン性界面活性剤（花王社製；エマルゲン２１０Ｐ）の３重量％メタノール溶液中に浸漬して風乾した。一方、測定対象の二次電池電極（多孔膜付電極）を直径１９ｍｍの円形に打ち抜いた。これらに電解液を含浸させ、これらを重ねて、一対の円形のＳＵＳ板（直径１５．５ｍｍ）に挟み、（ＳＵＳ板）／（円形の有機セパレーター）／（円形の二次電池電極）／（ＳＵＳ板）という構成に重ね合わせた。円形の二次電池電極は、その多孔膜側の面が有機セパレーター側となるよう配置した。ここで電解液はエチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）とをＥＣ：ＤＥＣ＝１：２（２０℃での容積比）で混合してなる混合溶媒にＬｉＰＦ６を１モル／リットルの濃度で溶解させた溶液を用いた。これを２０３２型コインセルに封入した。コインセルからリード線をとり、熱電対を付けてオーブンの中に入れた。振幅１０ｍＶ、１ｋＨｚの周波数の交流を印加しながら、昇温速度１．６℃／分で２００℃まで昇温させ、この間のセル抵抗を測定することで短絡の発生状況を確認した。本試験では温度上昇と共にシャットダウンにより抵抗値が上昇し少なくとも１０００Ω／ｃｍ２以上になる。その後、１０Ω／ｃｍ２以下まで急激に低下した場合に短絡が発生したものとした。尚、この試験を２０回行ない、評価は下記の基準で評価した。
　（評価基準）
　Ａ：短絡発生数０個
　Ｂ：短絡発生数１～２個
　Ｃ：短絡発生数３個以上 <Reliability test of secondary battery electrode (electrode with porous film)>
An organic separator (single-layer polypropylene separator, porosity 55%, thickness 25 μm) is punched into a circle with a diameter of 19 mm, and immersed in a 3% by weight methanol solution of a nonionic surfactant (manufactured by Kao Corporation; Emulgen 210P). And air dried. On the other hand, the secondary battery electrode (electrode with porous film) to be measured was punched into a circle having a diameter of 19 mm. These are impregnated with an electrolytic solution, and these are overlapped and sandwiched between a pair of circular SUS plates (diameter 15.5 mm), and (SUS plate) / (circular organic separator) / (circular secondary battery electrode) / ( SUS plate). The circular secondary battery electrode was arranged so that the surface on the porous membrane side was the organic separator side. Here, the electrolytic solution is a mixed solvent obtained by mixing ethylene carbonate (EC) and diethyl carbonate (DEC) at EC: DEC = 1: 2 (volume ratio at 20 ° C.). The concentration of LiPF 6 is 1 mol / liter. The solution dissolved in was used. This was enclosed in a 2032 type coin cell. I took the lead from the coin cell, put a thermocouple, and put it in the oven. While applying an alternating current with an amplitude of 10 mV and a frequency of 1 kHz, the temperature was raised to 200 ° C. at a temperature rising rate of 1.6 ° C./min, and the cell resistance during this time was measured to confirm the occurrence of a short circuit. In this test, the resistance value increases due to shutdown with a rise in temperature and becomes at least 1000 Ω / cm 2 or more. Thereafter, it was assumed that a short circuit occurred when the voltage dropped rapidly to 10 Ω / cm 2 or less. In addition, this test was performed 20 times and evaluation was performed according to the following criteria.
(Evaluation criteria)
A: Number of short-circuit occurrences 0 B: Number of short-circuit occurrences 1 to 2 C: Number of short-circuit occurrences 3 or more
＜二次電池のサイクル特性＞
　得られた二次電池（コイン型電池）を、２０℃で０．２Ｃの定電流で４．３Ｖまで充電し、０．２Ｃの定電流で３．０Ｖまで放電する操作を１サイクルとし、充放電を繰り返した。２サイクル目における放電容量に対する１００サイクル目おける放電容量の割合を百分率で算出して充放電サイクル特性とし、下記の基準で判定した。この値が大きいほど繰り返し充放電による容量減が少ないことを示す。
　（評価基準）
　Ａ：９７％以上
　Ｂ：９５％以上９７％未満
　Ｃ：９０％以上９５％未満
　Ｄ：８５％以上９０％未満
　Ｅ：８５％未満 <Cycle characteristics of secondary battery>
The operation of charging the obtained secondary battery (coin-type battery) to 4.3 V at a constant current of 0.2 C at 20 ° C. and discharging to 3.0 V at a constant current of 0.2 C is defined as one cycle. The discharge was repeated. The ratio of the discharge capacity in the 100th cycle to the discharge capacity in the second cycle was calculated as a percentage to obtain charge / discharge cycle characteristics, and the determination was made according to the following criteria. It shows that the capacity | capacitance reduction by repeated charging / discharging is so small that this value is large.
(Evaluation criteria)
A: 97% or more B: 95% or more and less than 97% C: 90% or more and less than 95% D: 85% or more and less than 90% E: Less than 85%
＜二次電池電極（多孔膜付電極）の粉落ち性＞
　二次電池電極（多孔膜付電極）を５ｃｍ角で切り出して、５００ｍｌのガラス瓶に入れ、しんとう機で３００ｒｐｍにて３時間しんとうさせた。落ちた粉の質量をａ、しんとう前の二次電池電極の質量をｂ、多孔膜を積層する前の電極の質量をｃ、多孔膜を積層していない電極のみをしんとうさせた際の落ちた粉の質量をｄとし、落ちた粉の比率Ｘ［質量％］を下記式で計算し、以下の基準で評価した。
　Ｘ＝（ａ－ｄ）／（ｂ－ｃ－ａ）×１００　［質量％］
（評価基準）
　Ａ：２質量％未満
　Ｂ：２質量％以上５質量％未満
　Ｃ：５質量％以上 <Powder removal property of secondary battery electrode (electrode with porous film)>
A secondary battery electrode (electrode with a porous film) was cut out at 5 cm square, put into a 500 ml glass bottle, and allowed to stand for 3 hours at 300 rpm with a machine. The mass of the dropped powder was a, the mass of the secondary battery electrode before the b was b, the mass of the electrode before laminating the porous film was c, and only the electrode without laminating the porous film was dropped The mass of the powder was d, and the ratio X [mass%] of the fallen powder was calculated by the following formula and evaluated according to the following criteria.
X = (ad) / (bca) × 100 [mass%]
(Evaluation criteria)
A: Less than 2% by mass B: 2% by mass or more and less than 5% by mass C: 5% by mass or more
＜二次電池セパレーター（多孔膜付有機セパレーター）の粉落ち性＞
　二次電池セパレーター（多孔膜付有機セパレーター）を５ｃｍ角で切り出して、５００ｍｌのガラス瓶に入れ、しんとう機で３００ｒｐｍにて３時間しんとうさせた。しんとう前の二次電池セパレーターの質量をａ、しんとう後の二次電池セパレーターの質量をｂとし、落ちた粉の比率Ｘ［質量％］を下記式で計算し、以下の基準で評価した。
　Ｘ＝（ａ－ｂ）／ａ×１００　［質量％］
（評価基準）
　Ａ：１質量％未満
　Ｂ：１質量％以上３質量％未満
　Ｃ：３質量％以上５質量％未満
　Ｄ：５質量％以上１０質量％未満
　Ｅ：１０質量％以上 <Powder removal performance of secondary battery separator (organic separator with porous membrane)>
A secondary battery separator (organic separator with a porous film) was cut out in a 5 cm square, placed in a 500 ml glass bottle, and allowed to stand for 3 hours at 300 rpm with a knitting machine. The mass of the secondary battery separator before the mating was a, the mass of the secondary battery separator after the mating was b, and the ratio X [% by mass] of the fallen powder was calculated by the following formula and evaluated according to the following criteria.
X = (ab) / a × 100 [mass%]
(Evaluation criteria)
A: Less than 1 mass% B: 1 mass% or more and less than 3 mass% C: 3 mass% or more and less than 5 mass% D: 5 mass% or more and less than 10 mass% E: 10 mass% or more
＜重合体粒子におけるスルホン酸基及びエポキシ基の含有割合の測定＞
　アクリル重合体粒子Ａの重合時に添加したスルホン酸基を有する単量体の添加量［ｇ］をａ、分子量をｂ、スルホン酸基部分に当たる分子量をｃ（８１．０７）、単量体全量をｄとすると、アクリル重合体粒子Ａにおける（単量体全量に対する）スルホン酸基の含有割合［質量％］が下記式のように計算される。
　アクリル重合体粒子Ａにおけるスルホン酸基の含有割合（Ａ）
　＝（ａ／ｂ）×ｃ／ｄ×１００　［質量％］ <Measurement of content ratio of sulfonic acid group and epoxy group in polymer particle>
The addition amount [g] of the monomer having a sulfonic acid group added during the polymerization of the acrylic polymer particle A is a, the molecular weight is b, the molecular weight corresponding to the sulfonic acid group portion is c (81.07), and the total amount of the monomer is Assuming d, the content ratio [% by mass] of the sulfonic acid group (relative to the total amount of monomers) in the acrylic polymer particles A is calculated as in the following formula.
Content ratio of sulfonic acid group in acrylic polymer particle A (A)
= (A / b) x c / d x 100 [mass%]
　同様にアクリル重合体粒子Ｂの重合時に添加したエポキシ基を有する単量体の添加量［ｇ］をｅ、分子量をｆ、エポキシ基部分に当たる分子量をｇ（４３．０５）、単量体全量をｈとすると、アクリル重合体粒子Ｂにおける（単量体全量に対する）エポキシ基の含有割合［質量％］が下記式のように計算される。
　アクリル重合体粒子Ｂにおけるエポキシ基の含有割合（Ｂ）
　　　　　　　　　　　 ＝（ｅ／ｆ）×ｇ／ｈ×１００　［質量％］ Similarly, the addition amount [g] of the monomer having an epoxy group added during the polymerization of the acrylic polymer particle B is e, the molecular weight is f, the molecular weight corresponding to the epoxy group portion is g (43.05), and the total amount of the monomer is Assuming that h, the content [% by mass] of the epoxy group (with respect to the total amount of the monomers) in the acrylic polymer particles B is calculated as in the following formula.
Content ratio of epoxy group in acrylic polymer particle B (B)
= (E / f) × g / h × 100 [mass%]
＜バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）の測定＞
　スラリー作成時に添加したアクリル重合体粒子Ａの固形分量［ｇ］をＣとし、スラリー作成時に添加したアクリル重合体粒子Ｂの固形分量［ｇ］をＤとした。さらに、重合体粒子におけるスルホン酸基及びエポキシ基の含有割合の測定にて得られた、アクリル重合体粒子Ａにおけるスルホン酸基の含有割合（Ａ）及びアクリル重合体粒子Ｂにおけるスルホン酸基の含有割合（Ｂ）を用いて、スルホン酸基／エポキシ基の重量比は下記のように計算できる。
　スルホン酸基／エポキシ基＝（Ａ×Ｃ）／（Ｂ×Ｄ）［重量比］ <Measurement of weight ratio of sulfonic acid group to epoxy group in binder (sulfonic acid group / epoxy group)>
The solid content [g] of the acrylic polymer particles A added at the time of slurry preparation was C, and the solid content [g] of the acrylic polymer particles B added at the time of slurry preparation was D. Furthermore, the content ratio (A) of the sulfonic acid group in the acrylic polymer particle A and the content of the sulfonic acid group in the acrylic polymer particle B obtained by measuring the content ratio of the sulfonic acid group and the epoxy group in the polymer particle. Using the ratio (B), the weight ratio of sulfonic acid group / epoxy group can be calculated as follows.
Sulfonic acid group / epoxy group = (A × C) / (B × D) [weight ratio]
（実施例１）
＜（１）シードポリマー粒子Ａの製造＞
　撹拌機を備えた反応器に、スチレン１００部、ドデシルベンゼンスルホン酸ナトリウム１．０部、イオン交換水１００部、及び過硫酸カリウム０．５部を入れ、８０℃で８時間重合させた。これにより、平均粒子径６０ｎｍのシードポリマー粒子Ａの水分散体を得た。 Example 1
<(1) Production of seed polymer particle A>
In a reactor equipped with a stirrer, 100 parts of styrene, 1.0 part of sodium dodecylbenzenesulfonate, 100 parts of ion-exchanged water, and 0.5 part of potassium persulfate were placed and polymerized at 80 ° C. for 8 hours. Thereby, an aqueous dispersion of seed polymer particles A having an average particle diameter of 60 nm was obtained.
＜（２）シードポリマー粒子Ｂの製造＞
　撹拌機を備えた反応器に、工程（１）で得たシードポリマー粒子Ａの水分散体を固形分基準（即ちシードポリマー粒子Ａの重量基準）で２部、ドデシルベンゼンスルホン酸ナトリウムを０．２部、過硫酸カリウムを０．５部、及びイオン交換水を１００部入れ、混合して混合物を得、８０℃に昇温した。一方、別の容器中でスチレン９７部、メタクリル酸３部、ｔ－ドデシルメルカプタン４部、ドデシルベンゼンスルホン酸ナトリウム０．５部、及びイオン交換水１００部を混合して、単量体混合物の分散体を調製した。この単量体混合物の分散体を、４時間かけて、上記混合物中に、連続的に添加して重合させた。単量体混合物の分散体の連続的な添加中における反応系の温度は８０℃に維持し、反応を行った。連続的な添加の終了後、さらに９０℃で３時間反応を継続させた。
　これにより、平均粒子径２００ｎｍのシードポリマー粒子Ｂの水分散体を得た。 <(2) Production of seed polymer particle B>
In a reactor equipped with a stirrer, 2 parts of the aqueous dispersion of the seed polymer particles A obtained in the step (1) on a solids basis (that is, on the basis of the weight of the seed polymer particles A) and 0. 2% of sodium dodecylbenzenesulfonate. 2 parts, 0.5 part of potassium persulfate and 100 parts of ion exchange water were added and mixed to obtain a mixture, which was heated to 80 ° C. Meanwhile, in another container, 97 parts of styrene, 3 parts of methacrylic acid, 4 parts of t-dodecyl mercaptan, 0.5 part of sodium dodecylbenzenesulfonate, and 100 parts of ion-exchanged water were mixed to disperse the monomer mixture. The body was prepared. The monomer mixture dispersion was continuously added to the mixture for 4 hours to polymerize. The reaction was carried out while maintaining the temperature of the reaction system at 80 ° C. during continuous addition of the dispersion of the monomer mixture. After completion of the continuous addition, the reaction was further continued at 90 ° C. for 3 hours.
Thereby, an aqueous dispersion of seed polymer particles B having an average particle diameter of 200 nm was obtained.
＜（３）非導電性粒子の製造＞
　次に、撹拌機を備えた反応器に、工程（２）で得たシードポリマー粒子Ｂの水分散体を固形分基準（即ちシードポリマー粒子Ｂ重量基準）で１０部、単量体混合物（ジビニルベンゼンとエチルビニルベンゼンの混合物、単量体混合比：ジビニルベンゼン／エチルビニルベンゼン＝６０／４０、新日鐵化学社製、製品名：ＤＶＢ－５７０）を９０部、ドデシルベンゼンスルホン酸ナトリウムを１部、重合開始剤としてｔ－ブチルパーオキシ－２－エチルヘキサノエート（日油社製、商品名：パーブチルＯ）を５部、及びイオン交換水を２００部入れ、３５℃で１２時間撹拌することで、シードポリマー粒子Ｂに単量体混合物及び重合開始剤を完全に吸収させた。その後、これを９０℃で４時間重合させた。その後、スチームを導入して未反応の単量体を除去した。
　これにより、平均粒子径０．４μｍの非導電性粒子の水分散体を得た。
　シードポリマー粒子の形成から、非導電性粒子を得るまでに用いた単量体（スチレン、メタクリル酸、ジビニルベンゼン、及びエチルビニルベンゼン）の組成、並びに非導電性粒子の耐熱温度（Ｔ１０値）、平均円形度及び粒子径分布は、表１に示す通りである。 <(3) Production of non-conductive particles>
Next, in a reactor equipped with a stirrer, 10 parts of the aqueous dispersion of the seed polymer particles B obtained in the step (2) on the basis of the solid content (that is, based on the weight of the seed polymer particles B) and a monomer mixture (divinyl) Mixture of benzene and ethyl vinyl benzene, monomer mixing ratio: divinyl benzene / ethyl vinyl benzene = 60/40, manufactured by Nippon Steel Chemical Co., Ltd., product name: DVB-570), 1 part sodium dodecylbenzene sulfonate 5 parts of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name: Perbutyl O) as a polymerization initiator and 200 parts of ion-exchanged water are added and stirred at 35 ° C. for 12 hours. Thus, the monomer mixture and the polymerization initiator were completely absorbed in the seed polymer particles B. Thereafter, this was polymerized at 90 ° C. for 4 hours. Thereafter, steam was introduced to remove unreacted monomers.
This obtained the water dispersion of the nonelectroconductive particle with an average particle diameter of 0.4 micrometer.
Composition of monomers (styrene, methacrylic acid, divinylbenzene, and ethylvinylbenzene) used from formation of seed polymer particles to obtaining nonconductive particles, and heat resistance temperature (T10 value) of nonconductive particles, The average circularity and particle size distribution are as shown in Table 1.
＜（４）アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８１．１部、アクリロニトリル１４．９部、２－アクリルアミド－２－メチルプロパンスルホン酸４．０部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は４．０％、スルホン酸基の含有割合は１．５６％、アクリロニトリル単量体単位の含有割合は１４．９％、（メタ）アクリル酸エステル単量体単位の含有割合は８１．１％であった。 <(4) Production of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 81.1 parts of n-butyl acrylate, 14.9 parts of acrylonitrile, 4.0 parts of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator 0.05 parts of mercaptan, 0.3 parts of potassium persulfate as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, sufficiently stirred, and then heated to 70 ° C. for polymerization, A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In acrylic polymer particle A, the content ratio of the monomer unit having a sulfonic acid group is 4.0%, the content ratio of the sulfonic acid group is 1.56%, the content ratio of the acrylonitrile monomer unit is 14.9%, The content ratio of the (meth) acrylic acid ester monomer unit was 81.1%.
＜（５）アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８１．９部、アクリロニトリル１５．１部、グリシジルメタクリレート３．０部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は３．０％、エポキシ酸基の含有割合は０．９１％、アクリロニトリル単量体単位の含有割合は１５．１％、（メタ）アクリル酸エステル単量体単位の含有割合は８１．９％であった。 <(5) Production of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 81.9 parts of n-butyl acrylate, 15.1 parts of acrylonitrile, 3.0 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, An aqueous polymer dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 3.0%, the content ratio of the epoxy acid group is 0.91%, the content ratio of the acrylonitrile monomer unit is 15.1%, The content ratio of the (meth) acrylic acid ester monomer unit was 81.9%.
＜（６）多孔膜スラリーの製造＞
　増粘剤として、エーテル化度が０．８～１．０で、１％水溶液粘度が１０～２０ｍＰａ・ｓであるカルボキシメチルセルロース（ダイセル化学工業株式会社製ダイセル１２２０）を用いて、１％水溶液を調製した。
　工程（３）で得た非導電性粒子の水分散体、工程（４）で得たアクリル重合体粒子Ａの水分散液、工程（５）で得たアクリル重合体粒子Ｂの水分散液及びカルボキシメチルセルロースの１％水溶液を、固形分重量比が８３．１：６．１５：６．１５：４．６となるように水中で混合し、更に溶媒として水を加えて、ビーズミルを用いて分散させ多孔膜スラリーを得た。なお、多孔膜スラリーにおける水以外の原料（固形分の合計）の含有量は、５０質量％となるようにした。
　なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が１．７であった。 <(6) Production of porous membrane slurry>
As the thickener, carboxymethyl cellulose (Daicel Chemical Industries, Ltd. Daicel 1220) having a degree of etherification of 0.8 to 1.0 and a 1% aqueous solution viscosity of 10 to 20 mPa · s was used to prepare a 1% aqueous solution. Prepared.
An aqueous dispersion of non-conductive particles obtained in step (3), an aqueous dispersion of acrylic polymer particles A obtained in step (4), an aqueous dispersion of acrylic polymer particles B obtained in step (5), and A 1% aqueous solution of carboxymethylcellulose is mixed in water so that the solid content weight ratio is 83.1: 6.15: 6.15: 4.6, and water is added as a solvent, followed by dispersion using a bead mill. To obtain a porous membrane slurry. In addition, content of raw materials other than water (total solid content) in the porous membrane slurry was set to 50% by mass.
The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.7.
＜（７）正極の製造＞
　正極活物質としてのスピネル構造を有するマンガン酸リチウム９５部に、電極用結着剤としてのＰＶＤＦ（ポリフッ化ビニリデン、呉羽化学社製、商品名：ＫＦ－１１００）を固形分換算量で３部となるように加え、さらに、アセチレンブラック２部、及びＮ－メチルピロリドン２０部を加えて、これらをプラネタリーミキサーで混合して、スラリー状の正極用電極組成物（正極用スラリー）を得た。この正極用スラリーを厚さ１８μｍのアルミニウム箔の片面に塗布し、１２０℃で３時間乾燥した後、ロールプレスして全厚みが１００μｍの、正極活物質層を有する正極を得た。 <(7) Production of positive electrode>
95 parts of lithium manganate having a spinel structure as a positive electrode active material and 3 parts of PVDF (polyvinylidene fluoride, manufactured by Kureha Chemical Co., Ltd., trade name: KF-1100) as an electrode binder in terms of solid content In addition, 2 parts of acetylene black and 20 parts of N-methylpyrrolidone were added and mixed with a planetary mixer to obtain a slurry-like positive electrode composition (positive electrode slurry). This positive electrode slurry was applied to one side of an aluminum foil having a thickness of 18 μm, dried at 120 ° C. for 3 hours, and then roll-pressed to obtain a positive electrode having a positive electrode active material layer having a total thickness of 100 μm.
＜（８）負極の製造＞
　負極活物質としての粒子径２０μｍ、比表面積４．２ｍ２／ｇのグラファイト９８部と、電極用結着剤としてのＳＢＲ（スチレン－ブタジエンゴム、ガラス転移温度：－１０℃）の固形分換算量１部とを混合し、この混合物にさらにカルボキシメチルセルロースを１．０部を混合し、更に溶媒として水を加えて、これらをプラネタリーミキサーで混合して、スラリー状の負極用電極組成物（負極用スラリー）を調製した。この負極用スラリーを厚さ１８μｍの銅箔の片面に塗布し、１２０℃で３時間乾燥した後、ロールプレスして全厚みが６０μｍの、負極活物質層を有する負極を得た。 <(8) Production of negative electrode>
Solid amount of 98 parts of graphite having a particle diameter of 20 μm as a negative electrode active material and a specific surface area of 4.2 m 2 / g and SBR (styrene-butadiene rubber, glass transition temperature: −10 ° C.) as an electrode binder 1 part is mixed, 1.0 part of carboxymethyl cellulose is further mixed with this mixture, water is further added as a solvent, and these are mixed with a planetary mixer to form a slurry-like negative electrode composition (negative electrode). Slurry) was prepared. This negative electrode slurry was applied to one side of a 18 μm thick copper foil, dried at 120 ° C. for 3 hours, and then roll pressed to obtain a negative electrode having a total thickness of 60 μm and having a negative electrode active material layer.
＜（９）二次電池セパレーター（多孔膜付有機セパレーター）の製造＞
　乾式法により製造された単層のポリプロピレン製セパレーター（気孔率５５％、厚さ２５μｍ）を、有機セパレーターとして用意した。この有機セパレーターの一方の面に、工程（６）で得た多孔膜スラリーを、乾燥後の厚みが５μｍとなるようにワイヤーバーを用いて塗布してスラリー層を得、スラリー層を５０℃で１０分間乾燥し、多孔膜を形成した。続いて、有機セパレーターの他方の面にも、同様に多孔膜を形成し、両面に多孔膜を有する、多孔膜付有機セパレーターを得た。 <(9) Production of secondary battery separator (organic separator with porous membrane)>
A single-layer polypropylene separator (porosity 55%, thickness 25 μm) produced by a dry method was prepared as an organic separator. On one surface of the organic separator, the porous membrane slurry obtained in the step (6) is applied using a wire bar so that the thickness after drying is 5 μm to obtain a slurry layer, and the slurry layer at 50 ° C. It was dried for 10 minutes to form a porous film. Subsequently, a porous film was similarly formed on the other surface of the organic separator, and an organic separator with a porous film having a porous film on both surfaces was obtained.
＜（１０）二次電池セパレーター（多孔膜付有機セパレーター）を有する二次電池の製造＞
　工程（７）で得られた正極を直径１３ｍｍの円形に切り抜いて、円形の正極を得た。工程（８）で得られた負極を直径１４ｍｍの円形に切り抜いて、円形の負極を得た。また、工程（９）で得た多孔膜付有機セパレーターを直径１８ｍｍの円形に切り抜いて、円形の多孔膜付有機セパレーターを得た。
　ポリプロピレン製パッキンを設けたステンレス鋼製のコイン型外装容器の内底面上に円形の正極を載置し、その上に円形の多孔膜付有機セパレーターを載置し、さらにその上に円形の負極を載置し、これらを容器内に収納した。円形の正極は、そのアルミニウム箔側の面が外装容器の底面側に向き、正極活物質層側の面が上側に向くよう載置した。円形の負極は、その負極活物質層側の面が円形の多孔膜付有機セパレーター側に向き、銅箔側の面が上側に向くよう載置した。この容器を１０５℃で２４時間、真空乾燥した。
　容器中に電解液を空気が残らないように注入し、ポリプロピレン製パッキンを介して外装容器に厚さ０．２ｍｍのステンレス鋼のキャップをかぶせて固定し、電池缶を封止して、直径２０ｍｍ、厚さ約３．２ｍｍのリチウムイオン二次電池（コインセルＣＲ２０３２）を製造した。電解液としてはエチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）とをＥＣ：ＤＥＣ＝１：２（２０℃での容積比）で混合してなる混合溶媒にＬｉＰＦ６を１モル／リットルの濃度で溶解させた溶液を用いた。 <(10) Production of Secondary Battery Having Secondary Battery Separator (Organic Separator with Porous Film)>
The positive electrode obtained in the step (7) was cut into a circle having a diameter of 13 mm to obtain a circular positive electrode. The negative electrode obtained in step (8) was cut into a circle having a diameter of 14 mm to obtain a circular negative electrode. Moreover, the organic separator with a porous film obtained in the step (9) was cut out into a circle having a diameter of 18 mm to obtain a circular organic separator with a porous film.
A circular positive electrode is placed on the inner bottom surface of a stainless steel coin-type outer container provided with polypropylene packing, a circular organic separator with a porous film is placed on it, and a circular negative electrode is placed thereon. They were placed and stored in a container. The circular positive electrode was placed so that the surface on the aluminum foil side faced the bottom surface side of the outer container and the surface on the positive electrode active material layer side faced upward. The circular negative electrode was placed so that the surface on the negative electrode active material layer side faced toward the organic separator with a circular porous film and the surface on the copper foil side faced upward. This container was vacuum-dried at 105 ° C. for 24 hours.
Inject the electrolyte into the container so that no air remains, fix the outer container with a 0.2 mm thick stainless steel cap through a polypropylene packing, seal the battery can, and 20 mm in diameter. A lithium ion secondary battery (coin cell CR2032) having a thickness of about 3.2 mm was manufactured. As an electrolytic solution, LiPF 6 is mixed at a concentration of 1 mol / liter in a mixed solvent obtained by mixing ethylene carbonate (EC) and diethyl carbonate (DEC) at EC: DEC = 1: 2 (volume ratio at 20 ° C.). The dissolved solution was used.
＜（１１）評価＞
　得られた多孔膜付有機セパレーターの多孔膜の均一性及び信頼性、粉落ち性、並びに得られた二次電池のサイクル特性を評価した。結果を表１に示す。 <(11) Evaluation>
The uniformity and reliability of the porous film of the obtained organic separator with a porous film, powder fall-off property, and cycle characteristics of the obtained secondary battery were evaluated. The results are shown in Table 1.
（実施例２）
　実施例１の工程（８）で得た負極の負極活物質層側の面に、実施例１の工程（６）で得た多孔膜スラリーを、負極活物質層が完全に覆われ、乾燥後の多孔膜厚みが５μｍとなるように塗布してスラリー層を得た。スラリー層を５０℃で１０分間乾燥し、多孔膜を形成し、多孔膜付負極を得た。得られた多孔膜付負極は、（多孔膜）／（負極活物質層）／（銅箔）の層構成を有していた。得られた多孔膜付負極の多孔膜の均一性及び信頼性、粉落ち性を評価した。結果を表１に示す。 (Example 2)
After the negative electrode active material layer is completely covered with the porous film slurry obtained in the step (6) of Example 1 on the negative electrode active material layer side surface of the negative electrode obtained in the step (8) of Example 1, after drying Was applied so that the thickness of the porous film was 5 μm to obtain a slurry layer. The slurry layer was dried at 50 ° C. for 10 minutes to form a porous film, and a negative electrode with a porous film was obtained. The obtained negative electrode with a porous film had a layer structure of (porous film) / (negative electrode active material layer) / (copper foil). The uniformity and reliability of the porous film of the obtained negative electrode with a porous film, and powder fall-off property were evaluated. The results are shown in Table 1.
　実施例１の工程（９）で得た多孔膜付有機セパレーターの代わりに、有機セパレーター（単層のポリプロピレン製セパレーター、気孔率５５％、厚さ２５μｍ、実施例１の工程（９）で有機セパレーターとして用いられているものと同じ）を用いた。 Instead of the organic separator with a porous membrane obtained in the step (9) of Example 1, an organic separator (single layer polypropylene separator, porosity 55%, thickness 25 μm, organic separator in the step (9) of Example 1 was used. The same as that used as a).
　また、実施例１の工程（８）で得た負極の代わりに、上記多孔膜付負極を用いたこと以外は、実施例１と同様の操作を行って、二次電池を得、評価を行った。結果を表１に示す。なお、円形の多孔膜付負極を外装容器内に載置するにあたっては、その多孔膜側の面が円形の有機セパレーター側に向き、銅箔側の面が上側に向くよう載置した。 Further, a secondary battery was obtained and evaluated in the same manner as in Example 1 except that the above negative electrode with a porous film was used instead of the negative electrode obtained in Step (8) of Example 1. It was. The results are shown in Table 1. In placing the negative electrode with a circular porous film in the outer container, the negative electrode was placed so that the porous film side faced to the circular organic separator side and the copper foil side faced to the upper side.
（実施例３）
　実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いた。また、実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いた。該アクリル重合体粒子Ａ及び該アクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が１．７であった。 (Example 3)
Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1. The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.7.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８９．０部、アクリロニトリル７．０部、２－アクリルアミド－２－メチルプロパンスルホン酸４．０部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａ１の水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は４．０％、スルホン酸基の含有割合は１．５６％、アクリロニトリル単量体単位の含有割合は７％、（メタ）アクリル酸エステル単量体単位の含有割合は８９％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 89.0 parts of n-butyl acrylate, 7.0 parts of acrylonitrile, 4.0 parts of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator 0.05 parts of mercaptan, 0.3 parts of potassium persulfate as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, sufficiently stirred, and then heated to 70 ° C. for polymerization. A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A1 was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. The acrylic polymer particle A has a sulfonic acid group-containing monomer unit content of 4.0%, a sulfonic acid group content of 1.56%, an acrylonitrile monomer unit content of 7%, ) The content of acrylic acid ester monomer units was 89%.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート９０．０部、アクリロニトリル７．０部、グリシジルメタクリレート３．０部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウムを１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は３．０％、エポキシ酸基の含有割合は０．９１％、アクリロニトリル単量体単位の含有割合は７％、（メタ）アクリル酸エステル単量体単位の含有割合は９０．０％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 90.0 parts of n-butyl acrylate, 7.0 parts of acrylonitrile, 3.0 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization After adding 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, the mixture is sufficiently stirred, and then heated to 70 ° C. to carry out polymerization to give an unreacted monomer A polymer aqueous dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 3.0%, the content ratio of the epoxy acid group is 0.91%, the content ratio of the acrylonitrile monomer unit is 7%, ) The content of acrylic acid ester monomer units was 90.0%.
（実施例４）
　実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いた。また、実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いた。該アクリル重合体粒子Ａ及び該アクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。
　なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が１．７であった。 Example 4
Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.7.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート６６．１部、アクリロニトリル２９．９部、２－アクリルアミド－２－メチルプロパンスルホン酸４．０部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は４．０％、スルホン酸基の含有割合は１．５６％、アクリロニトリル単量体単位の含有割合は２９．９％、（メタ）アクリル酸エステル単量体単位の含有割合は６６．１％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 66.1 parts of n-butyl acrylate, 29.9 parts of acrylonitrile, 4.0 parts of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator 0.05 parts of mercaptan, 0.3 parts of potassium persulfate as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, sufficiently stirred, and then heated to 70 ° C. for polymerization, A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. The acrylic polymer particle A has a sulfonic acid group-containing monomer unit content of 4.0%, a sulfonic acid group content of 1.56%, an acrylonitrile monomer unit content of 29.9%, The content ratio of the (meth) acrylic acid ester monomer unit was 66.1%.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート６６．８部、アクリロニトリル３０．２部、グリシジルメタクリレート３．０部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は３．０％、エポキシ酸基の含有割合は０．９１％、アクリロニトリル単量体単位の含有割合は３０．２％、（メタ）アクリル酸エステル単量体単位の含有割合は６６．８％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 66.8 parts of n-butyl acrylate, 30.2 parts of acrylonitrile, 3.0 parts of glycidyl methacrylate, 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, An aqueous polymer dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 3.0%, the content ratio of the epoxy acid group is 0.91%, the content ratio of the acrylonitrile monomer unit is 30.2%, The content ratio of the (meth) acrylic acid ester monomer unit was 66.8%.
（実施例５）
　実施例１の工程（１）～（３）で得た非導電性粒子の代わりに、下記の非導電性粒子を用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。 (Example 5)
The same operation as in Example 1 was performed except that the porous film slurry was produced using the following nonconductive particles instead of the nonconductive particles obtained in the steps (1) to (3) of Example 1. The organic separator with a porous membrane and the secondary battery were obtained and evaluated. The results are shown in Table 1.
＜非導電性粒子の製造＞
　撹拌機を備えた反応器に、実施例１の工程（１）、（２）で得たシードポリマー粒子Ｂの水分散体を固形分基準（即ちシードポリマー粒子Ｂ重量基準）で１０部、ジビニルベンゼンとエチルビニルベンゼンの混合物（単量体混合比：ジビニルベンゼン／エチルビニルベンゼン＝６０／４０、新日鐵化学社製、製品名：ＤＶＢ－５７０）を３３部、エチルビニルベンゼンを５７部、ドデシルベンゼンスルホン酸ナトリウムを１部、重合開始剤としてｔ－ブチルパーオキシ－２－エチルヘキサノエート（日油社製、商品名：パーブチルＯ）を５部、及びイオン交換水を２００部入れ、３５℃で１２時間撹拌することで、シードポリマー粒子Ｂに単量体混合物及び重合開始剤を完全に吸収させた。その後、これを９０℃で４時間重合させた。その後、スチームを導入して未反応の単量体を除去した。
　これにより、平均粒子径０．４μｍの非導電性粒子の水分散体を得た。
　シードポリマー粒子の形成から、非導電性粒子を得るまでに用いた単量体（スチレン、メタクリル酸、ジビニルベンゼン、及びエチルビニルベンゼン）の組成、並びに非導電性粒子の耐熱温度（Ｔ１０値）、平均円形度及び粒子径分布は、表１に示す通りである。 <Manufacture of non-conductive particles>
In a reactor equipped with a stirrer, 10 parts of an aqueous dispersion of seed polymer particles B obtained in steps (1) and (2) of Example 1 on a solids basis (ie, based on the weight of seed polymer particles B), divinyl A mixture of benzene and ethyl vinyl benzene (monomer mixture ratio: divinyl benzene / ethyl vinyl benzene = 60/40, manufactured by Nippon Steel Chemical Co., Ltd., product name: DVB-570), 33 parts, ethyl vinyl benzene 57 parts, 1 part of sodium dodecylbenzenesulfonate, 5 parts of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name: perbutyl O) as a polymerization initiator, and 200 parts of ion-exchanged water were added. By stirring at 35 ° C. for 12 hours, the seed polymer particles B were completely absorbed with the monomer mixture and the polymerization initiator. Thereafter, this was polymerized at 90 ° C. for 4 hours. Thereafter, steam was introduced to remove unreacted monomers.
This obtained the water dispersion of the nonelectroconductive particle with an average particle diameter of 0.4 micrometer.
Composition of monomers (styrene, methacrylic acid, divinylbenzene, and ethylvinylbenzene) used from formation of seed polymer particles to obtaining nonconductive particles, and heat resistance temperature (T10 value) of nonconductive particles, The average circularity and particle size distribution are as shown in Table 1.
（実施例６）
　実施例１の工程（１）～（３）で得た非導電性粒子の代わりに、下記の非導電性粒子を用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。 (Example 6)
The same operation as in Example 1 was performed except that the porous film slurry was produced using the following nonconductive particles instead of the nonconductive particles obtained in the steps (1) to (3) of Example 1. The organic separator with a porous membrane and the secondary battery were obtained and evaluated. The results are shown in Table 1.
＜シードポリマー粒子Ａの製造＞
　撹拌機を備えた反応器に、スチレン９５部、ジビニルベンゼン５部、ドデシルベンゼンスルホン酸ナトリウム１．０部、イオン交換水１００部、及び過硫酸カリウム０．５部を入れ、８０℃で８時間重合させた。これにより、平均粒子径６０ｎｍのシードポリマー粒子Ａの水分散体を得た。 <Production of seed polymer particle A>
In a reactor equipped with a stirrer, 95 parts of styrene, 5 parts of divinylbenzene, 1.0 part of sodium dodecylbenzenesulfonate, 100 parts of ion-exchanged water, and 0.5 part of potassium persulfate are placed at 80 ° C. for 8 hours. Polymerized. Thereby, an aqueous dispersion of seed polymer particles A having an average particle diameter of 60 nm was obtained.
＜非導電性粒子の製造＞
　撹拌機を備えた反応器に、上記シードポリマー粒子Ａの水分散体を用いたこと以外は、実施例１の工程(２)、（３）と同様に操作し、平均円形度が０．９１の非導電性粒子の水分散体を得た。シードポリマー粒子の形成から、非導電性粒子を得るまでに用いた単量体（スチレン、メタクリル酸、ジビニルベンゼン、及びエチルビニルベンゼン）の組成、並びに非導電性粒子の耐熱温度（Ｔ１０値）、平均粒子径及び粒子径分布は、表１に示す通りである。 <Manufacture of non-conductive particles>
The average circularity is 0.91 except that the aqueous dispersion of the seed polymer particles A is used in a reactor equipped with a stirrer, in the same manner as in steps (2) and (3) of Example 1. An aqueous dispersion of non-conductive particles was obtained. Composition of monomers (styrene, methacrylic acid, divinylbenzene, and ethylvinylbenzene) used from formation of seed polymer particles to obtaining nonconductive particles, and heat resistance temperature (T10 value) of nonconductive particles, The average particle size and particle size distribution are as shown in Table 1.
（実施例７）
　実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いた。また、実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いた。該アクリル重合体粒子Ａ及び該アクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。
　なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が３．４であった。 (Example 7)
Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 3.4.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８０．２部、アクリロニトリル１４．８部、２－アクリルアミド－２－メチルプロパンスルホン酸５．０部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は５．０％、スルホン酸基の含有割合は１．９５％、アクリロニトリル単量体単位の含有割合は１４．８％、（メタ）アクリル酸エステル単量体単位の含有割合は８０．２％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 80.2 parts of n-butyl acrylate, 14.8 parts of acrylonitrile, 5.0 parts of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator 0.05 parts of mercaptan, 0.3 parts of potassium persulfate as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, sufficiently stirred, and then heated to 70 ° C. for polymerization, A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. The acrylic polymer particle A has a sulfonic acid group-containing monomer unit content of 5.0%, a sulfonic acid group content of 1.95%, and an acrylonitrile monomer unit content of 14.8%. The content ratio of the (meth) acrylic acid ester monomer unit was 80.2%.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８２．９部、アクリロニトリル１５．２部、グリシジルメタクリレート１．９部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は１．９％、エポキシ酸基の含有割合は０．５８％、アクリロニトリル単量体単位の含有割合は１５．２％、（メタ）アクリル酸エステル単量体単位の含有割合は８２．９％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 82.9 parts of n-butyl acrylate, 15.2 parts of acrylonitrile, 1.9 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, An aqueous polymer dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 1.9%, the content ratio of the epoxy acid group is 0.58%, the content ratio of the acrylonitrile monomer unit is 15.2%, The content ratio of the (meth) acrylic acid ester monomer unit was 82.9%.
（実施例８）
実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いた。また、実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いた。該アクリル重合体粒子Ａ及び該アクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。
　なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が０．６であった。 (Example 8)
Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 0.6.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８２．６部、アクリロニトリル１５．２部、２－アクリルアミド－２－メチルプロパンスルホン酸２．２部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウムを１．０部入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は２．２％、スルホン酸基の含有割合は０．８６％、アクリロニトリル単量体単位の含有割合は１５．２％、（メタ）アクリル酸エステル単量体単位の含有割合は８２．６％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 82.6 parts of n-butyl acrylate, 15.2 parts of acrylonitrile, 2.2 parts of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator Mercaptan 0.05 part, potassium persulfate 0.3 part as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier was added, and after stirring sufficiently, the mixture was heated to 70 ° C. for polymerization, A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In acrylic polymer particle A, the content ratio of the monomer unit having a sulfonic acid group is 2.2%, the content ratio of the sulfonic acid group is 0.86%, the content ratio of the acrylonitrile monomer unit is 15.2%, The content ratio of the (meth) acrylic acid ester monomer unit was 82.6%.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８０．５部、アクリロニトリル１４．８部、グリシジルメタクリレート４．７部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は４．７％、エポキシ酸基の含有割合は１．４２％、アクリロニトリル単量体単位の含有割合は１４．８％、（メタ）アクリル酸エステル単量体単位の含有割合は８０．５％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 80.5 parts of n-butyl acrylate, 14.8 parts of acrylonitrile, 4.7 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, and unreacted monomers are removed. An aqueous polymer dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 4.7%, the content ratio of the epoxy acid group is 1.42%, the content ratio of the acrylonitrile monomer unit is 14.8%, The content ratio of the (meth) acrylic acid ester monomer unit was 80.5%.
（実施例９）
　実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いた。また、実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いた。該アクリル重合体粒子Ａ及び該アクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。
　なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が２．８であった。 Example 9
Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 2.8.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート７６．２部、アクリロニトリル１４．０部、２－アクリルアミド－２－メチルプロパンスルホン酸９．８部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は９．８％、スルホン酸基の含有割合は３．８２％、アクリロニトリル単量体単位の含有割合は１４．０％、（メタ）アクリル酸エステル単量体単位の含有割合は７６．２％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 76.2 parts of n-butyl acrylate, 14.0 parts of acrylonitrile, 9.8 parts of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator 0.05 parts of mercaptan, 0.3 parts of potassium persulfate as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, sufficiently stirred, and then heated to 70 ° C. for polymerization, A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle A, the content ratio of the monomer unit having a sulfonic acid group is 9.8%, the content ratio of the sulfonic acid group is 3.82%, the content ratio of the acrylonitrile monomer unit is 14.0%, The content ratio of the (meth) acrylic acid ester monomer unit was 76.2%.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８０．６部、アクリロニトリル１４．９部、グリシジルメタクリレート４．５部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は４．５％、エポキシ酸基の含有割合は１．３６％、アクリロニトリル単量体単位の含有割合は１４．９％、（メタ）アクリル酸エステル単量体単位の含有割合は８０．６％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 80.6 parts of n-butyl acrylate, 14.9 parts of acrylonitrile, 4.5 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, An aqueous polymer dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 4.5%, the content ratio of the epoxy acid group is 1.36%, the content ratio of the acrylonitrile monomer unit is 14.9%, The content ratio of the (meth) acrylic acid ester monomer unit was 80.6%.
（実施例１０）
　実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いた。また、実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いた。該アクリル重合体粒子Ａ及び該アクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。
　なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が１．８であった。 (Example 10)
Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.8.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８３．６部、アクリロニトリル１５．４部、２－アクリルアミド－２－メチルプロパンスルホン酸１．０部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は１．０％、スルホン酸基の含有割合は０．３９％、アクリロニトリル単量体単位の含有割合は１５．４％、（メタ）アクリル酸エステル単量体単位の含有割合は８３．６％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 83.6 parts of n-butyl acrylate, 15.4 parts of acrylonitrile, 1.0 part of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator 0.05 parts of mercaptan, 0.3 parts of potassium persulfate as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, sufficiently stirred, and then heated to 70 ° C. for polymerization, A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In acrylic polymer particle A, the content ratio of the monomer unit having a sulfonic acid group is 1.0%, the content ratio of the sulfonic acid group is 0.39%, the content ratio of the acrylonitrile monomer unit is 15.4%, The content ratio of the (meth) acrylic acid ester monomer unit was 83.6%.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８３．９部、アクリロニトリル１５．４部、グリシジルメタクリレート０．７部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は０．７％、エポキシ酸基の含有割合は０．２１％、アクリロニトリル単量体単位の含有割合は１５．４％、（メタ）アクリル酸エステル単量体単位の含有割合は８３．９％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 83.9 parts of n-butyl acrylate, 15.4 parts of acrylonitrile, 0.7 part of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, and unreacted monomers are removed. An aqueous polymer dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 0.7%, the content ratio of the epoxy acid group is 0.21%, the content ratio of the acrylonitrile monomer unit is 15.4%, The content ratio of the (meth) acrylic acid ester monomer unit was 83.9%.
（実施例１１）
　実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いた。また、実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いた。該アクリル重合体粒子Ａ及び該アクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。
　なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が１．５であった。 (Example 11)
Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles A were used. Moreover, the following acrylic polymer particle B was used instead of the acrylic polymer particle B obtained in the step (5) of Example 1. Except that the porous polymer slurry was produced using the acrylic polymer particles A and the acrylic polymer particles B, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation Went. The results are shown in Table 1.
The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.5.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート７７．９部、アクリロニトリル１４．４部、２－アクリルアミド－２－メチルプロパンスルホン酸７．７部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は７．７％、スルホン酸基の含有割合は３．００％、アクリロニトリル単量体単位の含有割合は１４．４％、（メタ）アクリル酸エステル単量体単位の含有割合は７７．９％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion exchange water, 77.9 parts of n-butyl acrylate, 14.4 parts of acrylonitrile, 7.7 parts of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator 0.05 parts of mercaptan, 0.3 parts of potassium persulfate as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, sufficiently stirred, and then heated to 70 ° C. for polymerization. A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle A, the content ratio of the monomer unit having a sulfonic acid group is 7.7%, the content ratio of the sulfonic acid group is 3.00%, the content ratio of the acrylonitrile monomer unit is 14.4%, The content ratio of the (meth) acrylic acid ester monomer unit was 77.9%.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート７８．７部、アクリロニトリル１４．５部、グリシジルメタクリレート６．８部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は６．８％、エポキシ酸基の含有割合は２．０６％、アクリロニトリル単量体単位の含有割合は１４．５％、（メタ）アクリル酸エステル単量体単位の含有割合は７８．７％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 78.7 parts of n-butyl acrylate, 14.5 parts of acrylonitrile, 6.8 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, and unreacted monomers are removed. An aqueous polymer dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 6.8%, the content ratio of the epoxy acid group is 2.06%, the content ratio of the acrylonitrile monomer unit is 14.5%, The content ratio of the (meth) acrylic acid ester monomer unit was 78.7%.
（実施例１２）
　実施例１の工程（１）～（３）で得た非導電性粒子の代わりに、下記の非導電性粒子を用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。 (Example 12)
The same operation as in Example 1 was performed except that the porous film slurry was produced using the following nonconductive particles instead of the nonconductive particles obtained in the steps (1) to (3) of Example 1. The organic separator with a porous membrane and the secondary battery were obtained and evaluated. The results are shown in Table 1.
＜シードポリマー粒子Ｃの製造＞
　撹拌機を備えた反応器に、実施例１の工程（２）で得たシードポリマー粒子Ｂの水分散体を固形分基準（即ちシードポリマー粒子Ｂ重量基準）で２部、ドデシルベンゼンスルホン酸ナトリウムを０．２部、過硫酸カリウムを０．５部、及びイオン交換水を１００部入れ、混合して混合物を得、８０℃に昇温した。一方、別の容器中でスチレン９７部、メタクリル酸３部、ｔ－ドデシルメルカプタン４部、ドデシルベンゼンスルホン酸ナトリウム０．５部、及びイオン交換水１００部を混合して、単量体混合物の分散体を調製した。この単量体混合物の分散体を、４時間かけて、上記混合物中に、連続的に添加して重合させた。単量体混合物の分散体の連続的な添加中の反応系の温度は８０℃に維持し、反応を行った。連続的な添加の終了後、さらに９０℃で３時間反応を継続させた。
　これにより、平均粒子径４００ｎｍのシードポリマー粒子Ｃの水分散体を得た。 <Manufacture of seed polymer particles C>
In a reactor equipped with a stirrer, 2 parts of the aqueous dispersion of seed polymer particles B obtained in step (2) of Example 1 on a solids basis (ie, based on the weight of seed polymer particles B), sodium dodecylbenzenesulfonate 0.2 parts, 0.5 parts of potassium persulfate and 100 parts of ion-exchanged water were mixed to obtain a mixture, and the temperature was raised to 80 ° C. Meanwhile, in another container, 97 parts of styrene, 3 parts of methacrylic acid, 4 parts of t-dodecyl mercaptan, 0.5 part of sodium dodecylbenzenesulfonate, and 100 parts of ion-exchanged water were mixed to disperse the monomer mixture. The body was prepared. The monomer mixture dispersion was continuously added to the mixture for 4 hours to polymerize. The temperature of the reaction system during continuous addition of the dispersion of the monomer mixture was maintained at 80 ° C. to carry out the reaction. After completion of the continuous addition, the reaction was further continued at 90 ° C. for 3 hours.
Thereby, an aqueous dispersion of seed polymer particles C having an average particle diameter of 400 nm was obtained.
＜非導電性粒子の製造＞
　実施例１の工程（２）で得たシードポリマー粒子Ｂの代わりに、上記シードポリマー粒子Ｃを用い、実施例１の工程（３）と同様の操作を行って、平均粒子径７００ｎｍの非導電性粒子の水分散体を得た。シードポリマーの形成から、非導電性粒子を得るまでに用いた単量体（スチレン、メタクリル酸、ジビニルベンゼン、及びエチルビニルベンゼン）の組成、並びに非導電性粒子の耐熱温度（Ｔ１０値）、平均円形度及び粒子径分布は、表１に示す通りである。 <Manufacture of non-conductive particles>
Using the seed polymer particle C in place of the seed polymer particle B obtained in the step (2) of Example 1, the same operation as in the step (3) of Example 1 was performed to obtain a non-conductive material having an average particle diameter of 700 nm. An aqueous dispersion of conductive particles was obtained. Composition of monomers (styrene, methacrylic acid, divinylbenzene, and ethylvinylbenzene) used from formation of seed polymer to obtaining nonconductive particles, heat resistance temperature (T10 value) of nonconductive particles, average The circularity and particle size distribution are as shown in Table 1.
（実施例１３）
　実施例１の工程（１）～（３）で得た非導電性粒子の代わりに、下記の非導電性粒子を用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。 (Example 13)
The same operation as in Example 1 was performed except that the porous film slurry was produced using the following nonconductive particles instead of the nonconductive particles obtained in the steps (1) to (3) of Example 1. The organic separator with a porous membrane and the secondary battery were obtained and evaluated. The results are shown in Table 1.
＜非導電性粒子の製造＞
　実施例１の工程（３）で用いた単量体混合物の代わりに、ジビニルベンゼンとエチルビニルベンゼンの混合物（単量体混合比：ジビニルベンゼン／エチルビニルベンゼン＝８２／１８、新日鐵化学社製、製品名：ＤＶＢ－８１０）を７２部、及びメチルメタクリレートを１８部用いたこと以外は、実施例１の工程（３）と同様の操作を行って、平均粒子径４００ｎｍの非導電性粒子の水分散体を得た。シードポリマー粒子の形成から、非導電性粒子を得るまでに用いた単量体（スチレン、メタクリル酸、ジビニルベンゼン、エチルビニルベンゼン、及びメチルメタクリレート）の組成、並びに非導電性粒子の耐熱温度（Ｔ１０値）、平均円形度及び粒子径分布は、表１に示す通りである。 <Manufacture of non-conductive particles>
Instead of the monomer mixture used in step (3) of Example 1, a mixture of divinylbenzene and ethylvinylbenzene (monomer mixture ratio: divinylbenzene / ethylvinylbenzene = 82/18, Nippon Steel Chemical Co., Ltd.) Product, product name: DVB-810) and non-conductive particles having an average particle diameter of 400 nm by performing the same operation as in step (3) of Example 1 except that 72 parts and 18 parts of methyl methacrylate were used. An aqueous dispersion was obtained. Composition of monomers (styrene, methacrylic acid, divinylbenzene, ethylvinylbenzene, and methyl methacrylate) used from formation of seed polymer particles to obtaining nonconductive particles, and heat resistance temperature of nonconductive particles (T10) Value), average circularity and particle size distribution are as shown in Table 1.
（実施例１４）
＜非導電性粒子のＮＭＰ分散体の作製＞
　実施例１の工程（３）で得た非導電性粒子の水分散体１００部（固形分濃度は２０％）にＮ－メチル－２－ピロリドン（ＮＭＰ）２００部を添加し十分に混合した後、９０℃減圧環境で系内の水およびＮＭＰを留去して、非導電性粒子のＮＭＰ分散体（固形分濃度は２０％）を得た。 (Example 14)
<Preparation of NMP dispersion of non-conductive particles>
After adding 200 parts of N-methyl-2-pyrrolidone (NMP) to 100 parts of an aqueous dispersion of non-conductive particles obtained in step (3) of Example 1 (solid content concentration: 20%) and mixing them well. The water and NMP in the system were distilled off in a 90 ° C. reduced pressure environment to obtain an NMP dispersion of nonconductive particles (solid content concentration 20%).
＜アクリル重合体粒子ＡのＮＭＰ分散体の作製＞
　実施例１の工程（４）で得たアクリル重合体粒子Ａの水分散体１００部（固形分は４０％）にＮＭＰ７６０部を添加し十分に混合した後、９０℃減圧環境で系内の水とＮＭＰを留去して、アクリル重合体粒子ＡのＮＭＰ分散体（固形分は１０％）を得た。 <Preparation of NMP dispersion of acrylic polymer particles A>
After adding 760 parts of NMP to 100 parts of the aqueous dispersion of acrylic polymer particles A obtained in the step (4) of Example 1 (solid content is 40%) and mixing them well, And NMP were distilled off to obtain an NMP dispersion (solid content: 10%) of acrylic polymer particles A.
＜アクリル重合体粒子ＢのＮＭＰ分散体の作製＞
　実施例１の工程（５）で得たアクリル重合体粒子Ｂの水分散体１００部（固形分は４０％）にＮＭＰ７６０部を添加し十分に混合した後、９０℃減圧環境で系内の水とＮＭＰを留去して、アクリル重合体粒子ＢのＮＭＰ分散体（固形分は１０％）を得た。 <Preparation of NMP dispersion of acrylic polymer particles B>
After adding 760 parts of NMP to 100 parts (solid content is 40%) of the aqueous dispersion of acrylic polymer particles B obtained in the step (5) of Example 1 and mixing them well, And NMP were distilled off to obtain an NMP dispersion (solid content: 10%) of acrylic polymer particles B.
＜多孔膜スラリーの製造＞
　上記の工程で得た非導電性粒子のＮＭＰ分散体、アクリル重合体粒子ＡのＮＭＰ分散体および、アクリル重合体粒子ＢのＮＭＰ分散体を、固形分比が８７．０：６．５：６．５となるよう混合して、固形分濃度１８％の多孔膜スラリーを得た。
　なお、多孔膜スラリー中のアクリル重合体粒子Ｂに対するアクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）は１、バインダーにおけるエポキシ基に対するスルホン酸基の重量比（スルホン酸基／エポキシ基）が１．７であった。 <Manufacture of porous membrane slurry>
The solid content ratio of the NMP dispersion of non-conductive particles, the NMP dispersion of acrylic polymer particles A, and the NMP dispersion of acrylic polymer particles B obtained in the above steps is 87.0: 6.5: 6. To obtain a porous membrane slurry having a solid content concentration of 18%.
The weight ratio of acrylic polymer particles A to acrylic polymer particles B in the porous membrane slurry (acrylic polymer particles A / acrylic polymer particles B) is 1, and the weight ratio of sulfonic acid groups to epoxy groups in the binder (sulfone Acid group / epoxy group) was 1.7.
＜多孔膜付負極の製造＞
　実施例１の工程（８）で得た負極の負極活物質層側の面に、上記の工程で得た多孔膜スラリーを、負極活物質層が完全に覆われ、乾燥後の多孔膜厚みが５μｍとなるように塗布してスラリー層を得た。スラリー層を１００℃で１０分間乾燥し、多孔膜を形成し、多孔膜付負極を得た。得られた多孔膜付負極は、（多孔膜）／（負極活物質層）／（銅箔）の層構成を有していた。得られた多孔膜付負極の多孔膜の均一性及び信頼性、粉落ち性を評価した。結果を表１に示す。 <Manufacture of negative electrode with porous film>
On the negative electrode active material layer side surface of the negative electrode obtained in the step (8) of Example 1, the negative electrode active material layer is completely covered with the porous film slurry obtained in the above step, and the porous film thickness after drying is The slurry layer was obtained by applying to 5 μm. The slurry layer was dried at 100 ° C. for 10 minutes to form a porous film, and a negative electrode with a porous film was obtained. The obtained negative electrode with a porous film had a layer structure of (porous film) / (negative electrode active material layer) / (copper foil). The uniformity and reliability of the porous film of the obtained negative electrode with a porous film, and powder fall-off property were evaluated. The results are shown in Table 1.
＜多孔膜付き負極を有する二次電池の製造＞
　実施例１の工程（９）で得た多孔膜付有機セパレーターの代わりに、有機セパレーター（単層のポリプロピレン製セパレーター、気孔率５５％、厚さ２５μｍ、実施例１の工程（９）で有機セパレーターとして用いられているものと同じ）を用いた。 <Production of secondary battery having negative electrode with porous film>
Instead of the organic separator with a porous membrane obtained in the step (9) of Example 1, an organic separator (single layer polypropylene separator, porosity 55%, thickness 25 μm, organic separator in the step (9) of Example 1 was used. The same as that used as a).
　また、実施例１の工程（８）で得た負極の代わりに、上記多孔膜付負極を用いたこと以外は、実施例１と同様の操作を行って、二次電池を得、評価を行った。結果を表１に示す。なお、円形の多孔膜付負極を外装容器内に載置するにあたっては、その多孔膜側の面が円形の有機セパレーター側に向き、銅箔側の面が上側に向くよう載置した。 Further, a secondary battery was obtained and evaluated in the same manner as in Example 1 except that the above negative electrode with a porous film was used instead of the negative electrode obtained in Step (8) of Example 1. It was. The results are shown in Table 1. In placing the negative electrode with a circular porous film in the outer container, the negative electrode was placed so that the porous film side faced to the circular organic separator side and the copper foil side faced to the upper side.
（比較例１）
　実施例１の工程（４）、（５）で得たアクリル重合体粒子Ａ、Ｂの代わりに、下記のアクリル重合体粒子Ｃを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。 (Comparative Example 1)
Example 1 except that the porous polymer slurry was produced using the following acrylic polymer particles C instead of the acrylic polymer particles A and B obtained in the steps (4) and (5) of Example 1. The same operation was performed to obtain an organic separator with a porous film and a secondary battery and evaluated. The results are shown in Table 1.
＜アクリル重合体粒子Ｃの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８１．５部、アクリロニトリル１５．０部、２－アクリルアミド－２－メチルプロパンスルホン酸２．０部、グリシジルメタクリレート１．５部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｃの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。また、アクリル重合体粒子Ｃはスルホン酸基とエポキシ基を有し、アクリル重合体粒子Ｃにおけるスルホン酸基の含有割合は０．７８％、エポキシ基の含有割合は０．４５％であった。 <Preparation of acrylic polymer particle C>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 81.5 parts of n-butyl acrylate, 15.0 parts of acrylonitrile, 2.0 parts of 2-acrylamido-2-methylpropanesulfonic acid, 1.5 parts of glycidyl methacrylate and Add 0.05 parts of t-dodecyl mercaptan as a molecular weight regulator, 0.3 parts of potassium persulfate as a polymerization initiator, and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier. Polymerization was performed by heating to obtain an aqueous polymer dispersion containing unreacted monomers. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles C was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. The acrylic polymer particle C had a sulfonic acid group and an epoxy group, and the acrylic polymer particle C had a sulfonic acid group content of 0.78% and an epoxy group content of 0.45%.
（比較例２）
　実施例１の工程（４）で得たアクリル重合体粒子Ａを用いず、実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。 (Comparative Example 2)
Instead of the acrylic polymer particles B obtained in the step (5) of Example 1, instead of using the acrylic polymer particles A obtained in the step (4) of Example 1, the following acrylic polymer particles B were used. Except that the porous membrane slurry was produced, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation was performed. The results are shown in Table 1.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート７８．７部、アクリロニトリル１４．５部、グリシジルメタクリレート６．８部、および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は６．８％、エポキシ酸基の含有割合は２．０６％、アクリロニトリル単量体単位の含有割合は１４．５％、（メタ）アクリル酸エステル単量体単位の含有割合は７８．７％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 78.7 parts of n-butyl acrylate, 14.5 parts of acrylonitrile, 6.8 parts of glycidyl methacrylate, and 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, polymerization Put 0.3 parts of potassium persulfate as an initiator and 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, and after sufficiently stirring, the mixture is heated to 70 ° C. to perform polymerization, and unreacted monomers are removed. An aqueous polymer dispersion containing was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle B, the content ratio of the monomer unit having an epoxy acid group is 6.8%, the content ratio of the epoxy acid group is 2.06%, the content ratio of the acrylonitrile monomer unit is 14.5%, The content ratio of the (meth) acrylic acid ester monomer unit was 78.7%.
（比較例３）
　実施例１の工程（５）で得たアクリル重合体粒子Ｂを用いず、実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。 (Comparative Example 3)
Instead of the acrylic polymer particles A obtained in the step (4) of Example 1, instead of using the acrylic polymer particles B obtained in the step (5) of Example 1, the following acrylic polymer particles A were used. Except that the porous membrane slurry was produced, the same operation as in Example 1 was performed to obtain an organic separator with a porous membrane and a secondary battery, and evaluation was performed. The results are shown in Table 1.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート７８．７部、アクリロニトリル１４．５部、２－アクリルアミド－２－メチルプロパンスルホン酸６．８部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は６．８％、スルホン酸基の含有割合は２．６５％、アクリロニトリル単量体単位の含有割合は１４．５％、（メタ）アクリル酸エステル単量体単位の含有割合は７８．７％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 78.7 parts of n-butyl acrylate, 14.5 parts of acrylonitrile, 6.8 parts of 2-acrylamido-2-methylpropanesulfonic acid and t-dodecyl as a molecular weight regulator 0.05 parts of mercaptan, 0.3 parts of potassium persulfate as a polymerization initiator, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier, sufficiently stirred, and then heated to 70 ° C. for polymerization. A polymer aqueous dispersion containing an unreacted monomer was obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. In the acrylic polymer particle A, the content ratio of the monomer unit having a sulfonic acid group is 6.8%, the content ratio of the sulfonic acid group is 2.65%, the content ratio of the acrylonitrile monomer unit is 14.5%, The content ratio of the (meth) acrylic acid ester monomer unit was 78.7%.
（比較例４）
　実施例１の工程（４）で得たアクリル重合体粒子Ａの代わりに、下記のアクリル重合体粒子Ａを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。なお、アクリル重合体粒子Ｂは、実施例１の工程（５）で得られたアクリル重合体粒子Ｂと同様のものを用いた。 (Comparative Example 4)
The same operation as in Example 1 was performed except that a porous membrane slurry was produced using the following acrylic polymer particles A instead of the acrylic polymer particles A obtained in the step (4) of Example 1. An organic separator with a porous film and a secondary battery were obtained and evaluated. The results are shown in Table 1. In addition, the acrylic polymer particle B used the thing similar to the acrylic polymer particle B obtained at the process (5) of Example 1. FIG.
＜アクリル重合体粒子Ａの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８４．５部、アクリロニトリル１５．５部および分子量調整剤としてｔ一ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ａの水分散液を得た。
なお、固形分濃度から求めた重合転化率はほぼ９９％であった。アクリル重合体粒子Ａにおけるスルホン酸基を有する単量体単位の含有割合は０％、スルホン酸基の含有割合は０％、アクリロニトリル単量体単位の含有割合は１５．５％、（メタ）アクリル酸エステル単量体単位の含有割合は８４．５％であった。 <Preparation of acrylic polymer particle A>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 84.5 parts of n-butyl acrylate, 15.5 parts of acrylonitrile, 0.05 part of t-dodecyl mercaptan as a molecular weight regulator, and potassium persulfate as a polymerization initiator were added in an amount of 0. 3 parts, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier is added, and after sufficiently stirring, polymerization is carried out by heating to 70 ° C., and a polymer aqueous dispersion containing unreacted monomers is prepared. Obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles A was obtained.
The polymerization conversion rate determined from the solid content concentration was approximately 99%. The content ratio of the monomer unit having a sulfonic acid group in the acrylic polymer particle A is 0%, the content ratio of the sulfonic acid group is 0%, the content ratio of the acrylonitrile monomer unit is 15.5%, (meth) acrylic The content rate of the acid ester monomer unit was 84.5%.
（比較例５）
　実施例１の工程（５）で得たアクリル重合体粒子Ｂの代わりに、下記のアクリル重合体粒子Ｂを用いて多孔膜スラリーを製造したこと以外は、実施例１と同様の操作を行って、多孔膜付有機セパレーター及び二次電池を得、評価を行った。結果を表１に示す。なお、アクリル重合体粒子Ａは、実施例１の工程（４）で得られたアクリル重合体粒子Ａと同様のものを用いた。 (Comparative Example 5)
The same operation as in Example 1 was performed except that a porous membrane slurry was produced using the following acrylic polymer particles B instead of the acrylic polymer particles B obtained in the step (5) of Example 1. An organic separator with a porous film and a secondary battery were obtained and evaluated. The results are shown in Table 1. In addition, the acrylic polymer particle A used the thing similar to the acrylic polymer particle A obtained at the process (4) of Example 1. FIG.
＜アクリル重合体粒子Ｂの作製＞
　撹拌機付きのオートクレーブに、イオン交換水３００部、ｎ－ブチルアクリレート８４．５部、アクリロニトリル１５．５部および分子量調整剤としてｔ－ドデシルメルカプタン０．０５部、重合開始剤として過硫酸カリウム０．３部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム１．０部を入れ、十分に撹拝した後、７０℃に加温して重合を行い、未反応の単量体を含有する重合体水分散液を得た。次いで、該重合体水分散液を２５℃に冷却し、これにアンモニア水を添加してｐＨを７に調整後、スチームを導入して未反応の単量体を除去し、平均粒子径０．１８μｍのアクリル重合体粒子Ｂの水分散液を得た。
なお、固形分濃度から求めた重合転化率はほぼ９９％であった。
　アクリル重合体粒子Ｂにおけるエポキシ酸基を有する単量体単位の含有割合は０％、エポキシ酸基の含有割合は０％、アクリロニトリル単量体単位の含有割合は１５．５％、（メタ）アクリル酸エステル単量体単位の含有割合は８４．５％であった。 <Preparation of acrylic polymer particle B>
In an autoclave equipped with a stirrer, 300 parts of ion-exchanged water, 84.5 parts of n-butyl acrylate, 15.5 parts of acrylonitrile, 0.05 part of t-dodecyl mercaptan as a molecular weight modifier, and potassium persulfate as a polymerization initiator were added in an amount of 0. 3 parts, 1.0 part of sodium dodecylbenzenesulfonate as an emulsifier is added, and after sufficiently stirring, polymerization is carried out by heating to 70 ° C., and a polymer aqueous dispersion containing unreacted monomers is prepared. Obtained. Next, the aqueous polymer dispersion was cooled to 25 ° C., and aqueous ammonia was added to adjust the pH to 7. Steam was introduced to remove unreacted monomers, and the average particle size was reduced to 0. An aqueous dispersion of 18 μm acrylic polymer particles B was obtained.
The polymerization conversion rate determined from the solid content concentration was approximately 99%.
The content ratio of the monomer unit having an epoxy acid group in the acrylic polymer particle B is 0%, the content ratio of the epoxy acid group is 0%, the content ratio of the acrylonitrile monomer unit is 15.5%, (meth) acrylic The content rate of the acid ester monomer unit was 84.5%.
（比較例６）
　実施例２の工程（４）、（５）で得たアクリル重合体粒子Ａ、Ｂの代わりに、比較例１で得られたアクリル重合体Ｃを用いて多孔膜スラリーを製造したこと以外は、実施例２と同様の操作を行って、多孔膜付負極及び二次電池を得、評価を行った。結果を表１に示す。 (Comparative Example 6)
Other than having produced the porous membrane slurry using the acrylic polymer C obtained in Comparative Example 1 instead of the acrylic polymer particles A and B obtained in the steps (4) and (5) of Example 2, The same operation as in Example 2 was performed to obtain a negative electrode with a porous film and a secondary battery, and evaluation was performed. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１の結果から、以下のことがいえる。
　有機高分子を含む非導電性粒子、及びバインダーを含んでなり、該バインダーが、スルホン酸基を有するアクリル重合体粒子Ａ、及びエポキシ基を有するアクリル重合体粒子Ｂからなる二次電池多孔膜スラリー（実施例１～１４）を用いて形成した二次電池多孔膜を有する二次電池セパレーター、二次電池電極及び二次電池は、多孔膜の均一性、信頼性、サイクル特性のバランスに優れる。
　一方、スルホン酸基とエポキシ基を一つの重合体粒子に有するバインダーを用いた場合（比較例１，６）、スルホン酸基を有さないバインダーを用いた場合（比較例２，４）、及びエポキシ基を有さないバインダーを用いた場合（比較例３，５）においては、多孔膜の均一性、信頼性、サイクル特性のバランスに劣る。 From the results in Table 1, the following can be said.
Secondary battery porous membrane slurry comprising non-conductive particles containing an organic polymer, and a binder, wherein the binder comprises acrylic polymer particles A having sulfonic acid groups and acrylic polymer particles B having epoxy groups The secondary battery separator, the secondary battery electrode and the secondary battery having the secondary battery porous film formed using Examples 1 to 14 are excellent in the balance of the uniformity, reliability and cycle characteristics of the porous film.
On the other hand, when using a binder having a sulfonic acid group and an epoxy group in one polymer particle (Comparative Examples 1 and 6), using a binder having no sulfonic acid group (Comparative Examples 2 and 4), and In the case of using a binder having no epoxy group (Comparative Examples 3 and 5), the balance of the uniformity, reliability, and cycle characteristics of the porous film is inferior.

Claims (13)

  1. 　有機高分子を含む非導電性粒子、バインダー及び溶媒を含んでなり、
    　該バインダーが、スルホン酸基を有するアクリル重合体粒子Ａ、及びエポキシ基を有するアクリル重合体粒子Ｂを含む二次電池多孔膜スラリー。     Comprising non-conductive particles containing organic polymer, binder and solvent,
    The secondary battery porous membrane slurry in which the binder contains acrylic polymer particles A having sulfonic acid groups and acrylic polymer particles B having epoxy groups.
  2. 　全固形分１００質量％当たりの前記非導電性粒子の含有割合が７０～９７質量％、前記バインダーの含有割合が０．５～２０質量％である請求項１に記載の二次電池多孔膜スラリー。 The secondary battery porous membrane slurry according to claim 1, wherein the content ratio of the nonconductive particles per 100 mass% of the total solid content is 70 to 97 mass%, and the content ratio of the binder is 0.5 to 20 mass%. .
  3. 　前記アクリル重合体粒子Ａ及び前記アクリル重合体粒子Ｂが、
    　（メタ）アクリロニトリル単量体単位、及び（メタ）アクリル酸エステル単量体単位を含んでなる請求項１または２に記載の二次電池多孔膜スラリー。     The acrylic polymer particles A and the acrylic polymer particles B are
    The secondary battery porous membrane slurry according to claim 1 or 2, comprising a (meth) acrylonitrile monomer unit and a (meth) acrylic acid ester monomer unit.
  4. 　前記アクリル重合体粒子Ａ及び前記アクリル重合体粒子Ｂにおける、
    　重合体粒子中の（メタ）アクリロニトリル単量体単位の含有割合が２．５～４０質量％であり、
    　重合体粒子中の（メタ）アクリル酸エステル単量体単位の含有割合が６０～９７．５質量％である請求項３に記載の二次電池多孔膜スラリー。     In the acrylic polymer particles A and the acrylic polymer particles B,
    The content ratio of the (meth) acrylonitrile monomer unit in the polymer particles is 2.5 to 40% by mass,
    The secondary battery porous membrane slurry according to claim 3, wherein the content ratio of the (meth) acrylate monomer units in the polymer particles is 60 to 97.5 mass%.
  5. 　前記アクリル重合体粒子Ｂに対する前記アクリル重合体粒子Ａの重量比（アクリル重合体粒子Ａ／アクリル重合体粒子Ｂ）が０．３～３である請求項１～４のいずれかに記載の二次電池多孔膜スラリー。 The secondary according to any one of claims 1 to 4, wherein a weight ratio of the acrylic polymer particles A to the acrylic polymer particles B (acrylic polymer particles A / acrylic polymer particles B) is 0.3 to 3. Battery porous membrane slurry.
  6. 　前記アクリル重合体粒子Ａにおけるスルホン酸基の含有割合が０．０４～５．８質量％、前記アクリル重合体粒子Ｂにおけるエポキシ基の含有割合が０．０３～３．０質量％である、請求項１～５のいずれかに記載の二次電池多孔膜スラリー。 The sulfonic acid group content in the acrylic polymer particles A is 0.04 to 5.8% by mass, and the epoxy group content in the acrylic polymer particles B is 0.03 to 3.0% by mass. Item 6. The secondary battery porous membrane slurry according to any one of Items 1 to 5.
  7. 　前記バインダーにおける、前記アクリル重合体粒子Ｂにおけるエポキシ基に対する前記アクリル重合体粒子Ａにおけるスルホン酸基の重量比（スルホン酸基／エポキシ基）が０．２～３である請求項１～６のいずれかに記載の二次電池多孔膜スラリー。 The weight ratio of the sulfonic acid groups in the acrylic polymer particles A to the epoxy groups in the acrylic polymer particles B (sulfonic acid groups / epoxy groups) in the binder is 0.2 to 3. A secondary battery porous membrane slurry according to claim 1.
  8. 　熱天秤により窒素雰囲気下で昇温速度１０℃／分で加熱したときの前記非導電性粒子の減量割合が１０質量％に達する温度が２５０℃以上であり、
    　該非導電性粒子の平均粒子径が０．１～２．０μｍであり、
    　該非導電性粒子の平均円形度が０．９００～０．９９５である請求項１～７のいずれかに記載の二次電池多孔膜スラリー。     The temperature at which the weight loss ratio of the non-conductive particles reaches 10% by mass when heated at a rate of temperature increase of 10 ° C./min in a nitrogen atmosphere by a thermobalance is 250 ° C. or more,
    The non-conductive particles have an average particle size of 0.1 to 2.0 μm;
    The secondary battery porous membrane slurry according to any one of claims 1 to 7, wherein the non-conductive particles have an average circularity of 0.900 to 0.995.
  9. 　請求項１～８のいずれかに記載の二次電池多孔膜スラリーを、膜状に形成、乾燥してなる二次電池多孔膜。 A secondary battery porous membrane obtained by forming the secondary battery porous membrane slurry according to any one of claims 1 to 8 into a film shape and drying it.
  10. 　集電体、
    　該集電体に付着してなる、電極活物質及び電極用結着剤を含んでなる電極活物質層、及び、
    　該電極活物質層の表面に積層された、請求項９に記載の二次電池多孔膜、を含んでなる、二次電池電極。     Current collector,
    An electrode active material layer comprising an electrode active material and an electrode binder, which is attached to the current collector; and
    A secondary battery electrode comprising the secondary battery porous film according to claim 9, which is laminated on a surface of the electrode active material layer.
  11. 　有機セパレーター、
    　該有機セパレーターに積層された、請求項９に記載の二次電池多孔膜、を含んでなる、二次電池セパレーター。     Organic separator,
    A secondary battery separator comprising the secondary battery porous film according to claim 9, which is laminated on the organic separator.
  12. 　正極、負極、有機セパレーター及び電解液を含む二次電池であって、前記正極、負極及び有機セパレーターのいずれかに、請求項９に記載の二次電池多孔膜が積層されてなる二次電池。 A secondary battery including a positive electrode, a negative electrode, an organic separator, and an electrolyte solution, wherein the secondary battery porous film according to claim 9 is laminated on any of the positive electrode, the negative electrode, and the organic separator.
  13. 　請求項１～８のいずれかに記載の二次電池多孔膜スラリーを基材に塗布し、次いで乾燥する工程を含む二次電池多孔膜の製造方法。 A method for producing a secondary battery porous membrane, comprising a step of applying the secondary battery porous membrane slurry according to any one of claims 1 to 8 to a substrate and then drying.
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