WO2022138371A1 - Non-aqueous secondary battery electrode binder, non-aqueous secondary battery electrode binder composition, and non-aqueous secondary battery - Google Patents

Non-aqueous secondary battery electrode binder, non-aqueous secondary battery electrode binder composition, and non-aqueous secondary battery Download PDF

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Publication number
WO2022138371A1
WO2022138371A1 PCT/JP2021/046248 JP2021046248W WO2022138371A1 WO 2022138371 A1 WO2022138371 A1 WO 2022138371A1 JP 2021046248 W JP2021046248 W JP 2021046248W WO 2022138371 A1 WO2022138371 A1 WO 2022138371A1
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Prior art keywords
copolymer
structural unit
secondary battery
aqueous secondary
mol
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PCT/JP2021/046248
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French (fr)
Japanese (ja)
Inventor
勇汰 川原
亮介 池端
秀雄 堀越
充 花▲崎▼
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昭和電工株式会社
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Priority to JP2022572222A priority Critical patent/JPWO2022138371A1/ja
Priority to CN202180085858.0A priority patent/CN116745328A/en
Priority to KR1020237021163A priority patent/KR20230124923A/en
Publication of WO2022138371A1 publication Critical patent/WO2022138371A1/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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F212/02—Monomers containing only one unsaturated aliphatic radical
    • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
    • C08F212/06—Hydrocarbons
    • C08F212/08—Styrene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
    • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
    • C08G65/32—Polymers modified by chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
    • C08L25/02—Homopolymers or copolymers of hydrocarbons
    • C08L25/04—Homopolymers or copolymers of styrene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
    • C08L71/02—Polyalkylene oxides
    • 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
    • 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
    • H01M4/139—Processes of manufacture
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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

Definitions

  • the present invention relates to a non-aqueous secondary battery electrode binder, a non-aqueous secondary battery electrode binder composition, and a non-aqueous secondary battery electrode.
  • the non-aqueous secondary battery includes, for example, a positive electrode using a metal oxide or the like as a positive electrode active material, a negative electrode using a material such as graphite as a negative electrode active material, and an electrolytic solution.
  • a non-aqueous secondary battery is a secondary battery in which ions serving as charge carriers move between a positive electrode and a negative electrode to charge and discharge the battery.
  • a typical example is a lithium ion secondary battery as a non-aqueous secondary battery.
  • Non-aqueous secondary batteries are used as power sources for notebook computers, mobile phones, power tools, and electronic / communication devices in terms of miniaturization and weight reduction. Recently, it has also been used in electric vehicles, hybrid vehicles, and the like from the viewpoint of application to environmental vehicles. Under these circumstances, there is a strong demand for higher output, higher capacity, longer life, etc. of non-aqueous secondary batteries.
  • the binder used for the positive electrode and the negative electrode has a role of binding the electrode active material to each other and a role of binding the electrode active material and the current collector.
  • Water dispersion binders are being developed to improve the capacity of non-aqueous secondary batteries and protect the working environment.
  • a styrene-butadiene rubber (SBR) -based aqueous dispersion using carboxymethyl cellulose (CMC) as a thickener is known.
  • Patent Document 1 describes a method for polymerizing ethylene oxide with an alkylene oxide other than ethylene oxide, an alkyl glycidyl ether, an allyl glycidyl ether, or a combination thereof. It is described that the composition containing the copolymer obtained by polymerization can be used as a binder material in a battery electrode containing electroactive particles.
  • Patent Document 2 a copolymer obtained from a (meth) acrylic acid ester and a vinyl monomer having an acid component; a polyoxyethylene alkyl ether derivative, a polyoxyethylene-polyoxypropylene condensate, and a polyoxyethylene-
  • a secondary battery negative electrode comprising an electrode layer containing at least one selected from the group consisting of polyoxypropylene alkyl ether derivatives; is described.
  • Patent Documents 1 and 2 when used as a binder for electrodes, there is room for improving the peel strength of the electrode active material layer with respect to the current collector, and the internal resistance is reduced when the battery is manufactured. There is room for.
  • the present invention is a non-aqueous secondary battery electrode binder that can effectively improve the peeling strength of the electrode active material layer with respect to the current collector in a non-aqueous secondary battery, and contribute to the reduction of the internal resistance of the battery and the improvement of the cycle characteristics. It is an object of the present invention to provide a non-aqueous secondary battery electrode binder composition and a non-aqueous secondary battery electrode.
  • the copolymer (A) is a polymer of a compound having an ethylenically unsaturated bond.
  • the copolymer (A) has an eleventh structural unit derived from the monomer (a1) and a twelfth structural unit derived from the monomer (a2); or the monomer (a1). ), A twelfth structural unit derived from the monomer (a2), and a thirteenth structural unit derived from the internal cross-linking agent (a3).
  • the monomer (a1) is a nonionic compound having an ethylenically unsaturated bond, having neither a hydroxy group nor a cyano group, and having a plurality of independent ethylenically unsaturated bonds.
  • the monomer (a2) is a compound having an ethylenically unsaturated bond and an anionic functional group and not having a plurality of independent ethylenically unsaturated bonds.
  • the internal cross-linking agent (a3) has a plurality of independent ethylenically unsaturated bonds and forms a cross-linked structure by radical polymerization of the monomer (a1) and the monomer containing the monomer (a2).
  • the content of the 12th structural unit with respect to 100 parts by mass of the 11th structural unit is 1.0 part by mass or more and 30 parts by mass or less.
  • the content of the 13th structural unit with respect to 100 parts by mass of the 11th structural unit is 0 parts by mass or more and 20 parts by mass or less.
  • the copolymer (B) contains the 21st structural unit represented by the following formula (1) in an amount of 5.0 mol% or more and 98 mol% or less, and the 22nd structure represented by the following formula (2).
  • the unit has 0.30 mol% or more and 90 mol% or less in all structural units, and the 23rd structural unit represented by the following formula (3) has 0.30 mol% or more and 10 mol% or less in all structural units.
  • the total content of the 21st structural unit, the 22nd structural unit, and the 23rd structural unit in the total structural unit of the copolymer (B) is 90% by mass or more.
  • the mass ratio of the content of the copolymer (A) to the content of the copolymer (B) is 50.0 / 50.0 or more and 99.0 / 1.0 or less.
  • Non-aqueous secondary battery electrode binder is
  • R 1 is an alkyl group having 1 or more and 6 or less carbon atoms which may have a branch.
  • R 2 is a group having an ethylenically unsaturated bond.
  • the copolymer (B) is The 21st structural unit is 5.0 mol% or more and 50 mol% or less, The 22nd structural unit is 40 mol% or more and 90 mol% or less, The non-aqueous secondary battery electrode binder according to [1], which contains the 23rd structural unit in an amount of 0.30 mol% or more and 10 mol% or less.
  • the copolymer (B) is The 21st structural unit is 70 mol% or more and 98 mol% or less, The 22nd structural unit is 0.30 mol% or more and 20 mol% or less, The non-aqueous secondary battery electrode binder according to [1], which contains the 23rd structural unit in an amount of 0.30 mol% or more and 10 mol% or less.
  • R 2 is a non-aqueous secondary battery electrode binder according to any one of [1] to [4] represented by the following formula (4).
  • R 21 is an alkylene group having 1 to 5 carbon atoms which may have a branch
  • R 22 is a vinyloxy group, an allyloxy group, a (meth) acryloyl group, and a (meth) acryloyloxy.
  • the block copolymer (B) is a block copolymer having a first block composed of a 21st structural unit, a second block composed of a 22nd structural unit, and a third block composed of a 23rd structural unit.
  • the copolymer (A) contains 80% by mass or more of the 11th structural unit and the 12th structural unit in total. binder.
  • the content of the 13th structural unit with respect to 100 parts by mass of the 11th structural unit is 0.050 parts by mass or more, any of [1] to [9].
  • a non-aqueous secondary battery electrode binder composition comprising the non-aqueous secondary battery electrode binder according to any one of [1] to [10] and an aqueous medium.
  • the non-aqueous secondary battery electrode binder according to any one of [1] to [10], an electrode active material, and an aqueous medium are included.
  • the aqueous medium is a non-aqueous secondary battery electrode slurry which is one medium selected from the group consisting of water, a hydrophilic solvent, and a mixture containing water and a hydrophilic solvent.
  • a non-aqueous secondary battery electrode comprising the non-aqueous secondary battery electrode binder according to any one of [1] to [10].
  • the peeling strength of the electrode active material layer with respect to the current collector can be effectively improved, and the non-aqueous secondary battery electrode can contribute to the reduction of the internal resistance of the battery and the improvement of the cycle characteristics.
  • Binders, non-aqueous secondary battery electrode binder compositions, and non-aqueous secondary battery electrodes can be provided.
  • both a non-aqueous secondary battery electrode binder also referred to as a non-aqueous secondary battery electrode binder
  • a non-aqueous secondary battery electrode binder composition also referred to as a non-aqueous secondary battery electrode binder composition
  • a non-aqueous secondary battery electrode slurry also referred to as a non-aqueous secondary battery electrode slurry
  • a non-aqueous secondary battery electrode and a non-aqueous secondary battery
  • (Meta) acrylic is a general term for acrylic and methacrylic
  • (meth) acrylate is a general term for acrylate and methacrylate.
  • the “nonvolatile component” is a component remaining after weighing 1 g of the composition in an aluminum dish having a diameter of 5 cm and drying at 105 ° C. for 1 hour while circulating air in a dryer at 1 atm (1013 hPa).
  • the form of the composition includes, but is not limited to, a solution, a dispersion, and a slurry.
  • the “nonvolatile content concentration” is the mass ratio (mass%) of the non-volatile content after drying under the above conditions with respect to the mass (1 g) of the composition before drying.
  • Ethylene unsaturated bond refers to an ethylenically unsaturated bond having radical polymerization unless otherwise specified.
  • the structural unit derived from the compound having a certain ethylenically unsaturated bond is the chemical structure of the portion other than the ethylenically unsaturated bond of the compound and its structure in the polymer. It is assumed that the chemical structure of the part other than the part corresponding to the ethylenically unsaturated bond of the unit is the same.
  • the structural unit derived from acrylic acid has a structure of ⁇ CH 2 CH (COOH) ⁇ in the polymer.
  • an ethylenically unsaturated bond may remain as a structural unit of the polymer.
  • a plurality of independent ethylenically unsaturated bonds are a plurality of ethylenically unsaturated bonds that do not form conjugated diene with each other.
  • the structural unit derived from divinylbenzene may have a structure having no ethylenically unsaturated bond (a form in which a portion corresponding to any ethylenically unsaturated bond is incorporated into a polymer chain), or one ethylene.
  • a structure having a sex-unsaturated bond (a form in which only the portion corresponding to one ethylenically unsaturated bond is incorporated into the polymer chain) may be used.
  • the chemical structure of the monomer does not correspond to the chemical structure of the polymer, such as chemical reaction of the part other than the chain corresponding to the ethylenically unsaturated bond after polymerization
  • the chemical structure after polymerization is used as a reference. ..
  • vinyl acetate is polymerized and then saponified, it is not a structural unit derived from vinyl acetate but a structural unit derived from vinyl alcohol in consideration of the chemical structure of the polymer.
  • Non-aqueous secondary battery electrode binder contains the copolymer (A) and the copolymer (B).
  • the electrode binder means a non-aqueous secondary battery electrode binder according to the present invention.
  • the electrode binder may contain other components, and may contain, for example, a polymer other than the copolymer (A) and the copolymer (B).
  • the non-aqueous secondary battery electrode binder according to the present invention is preferably made of the copolymer (A) and the copolymer (B).
  • the copolymer (A) and the copolymer (B) will be described in detail.
  • the copolymer (A) is a polymer of a compound having an ethylenically unsaturated bond.
  • the copolymer (A) has an eleventh structural unit derived from the monomer (a1) and a twelfth structural unit derived from the monomer (a2).
  • the copolymer (A) may further have a thirteenth structural unit derived from the internal cross-linking agent (a3).
  • the copolymer (A) contains a structural unit derived from another monomer (a4) that does not fall under any of the monomer (a1), the monomer (a2), and the internal cross-linking agent (a3). But it may be. Details of each monomer and internal cross-linking agent will be described below.
  • the monomer (a1) is a nonionic (neither anionic or cationic functional group) compound having an ethylenically unsaturated bond and not having a plurality of independent ethylenically unsaturated bonds. be.
  • the monomer (a1) preferably does not have a polyoxyalkylene structure.
  • the monomer (a1) has neither a hydroxy group nor a cyano group.
  • the monomer (a1) preferably has no polar functional group.
  • the monomer (a1) may contain only one kind of compound, or may contain two or more kinds of compounds.
  • the monomer (a1) is preferably at least one of a (meth) acrylic acid ester having no polar functional group and an aromatic vinyl compound, and more preferably containing both.
  • the (meth) acrylic acid ester having no polar functional group more preferably contains a (meth) acrylic acid alkyl ester.
  • the total content of the (meth) acrylic acid alkyl ester and the aromatic vinyl compound in the monomer (a1) is more preferably 80% by mass or more, further preferably 90% by mass or more, and 100% by mass. Is most preferable.
  • composition of the monomer (a1) in order to adjust the glass transition point of the copolymer (A) or to adjust the polymerization rate according to the molecular design, within the range specified in the present invention. It is preferable to appropriately adjust the preferred compound and the amount thereof.
  • Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, n-propyl (meth) acrylic acid, isopropyl (meth) acrylic acid, and n-butyl (meth) acrylic acid. , (Meta) tert-butyl acrylate, (meth) cyclohexyl acrylate, (meth) 2-ethylhexyl acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and the like. ..
  • the aromatic vinyl compound does not contain a (meth) acryloyl group.
  • the aromatic vinyl compound include styrene, t-butylstyrene, ⁇ -methylstyrene, p-methylstyrene, 1,1-diphenylethylene and the like.
  • the monomer (a1) contains an aromatic vinyl compound
  • the monomer (a1) more preferably contains at least one of styrene and ⁇ -methylstyrene, and further preferably contains styrene.
  • the monomer (a1) may contain a plurality of ethylenically unsaturated bonds forming conjugated diene with each other.
  • Examples of the compound having a plurality of ethylenically unsaturated bonds forming conjugated diene with each other include 1,3-butadiene, 1,3-pentadiene and the like.
  • the monomer (a2) is a compound having an ethylenically unsaturated bond and an anionic functional group.
  • the monomer (a2) does not have multiple independent ethylenically unsaturated bonds.
  • the monomer (a2) preferably does not have a polyoxyalkylene structure.
  • Examples of the anionic functional group include a carboxy group, a sulfo group, a phosphoric acid group and the like. Further, the anionic functional group may form a salt.
  • the monomer (a2) preferably contains a compound having at least one of a carboxy group and a sulfo group, and more preferably contains a compound having a carboxy group.
  • the monomer (a2) may contain only one kind of compound, or may contain two or more kinds of compounds.
  • the monomer (a2) may contain a compound having a plurality of the same kind of anionic functional groups in one molecule. That is, the copolymer (A) may contain a plurality of anionic functional groups of the same type in one structural unit.
  • the monomer (a2) may contain a compound having two or more different anionic functional groups in one molecule. That is, the copolymer (A) may contain two or more different anionic functional groups in one structural unit.
  • the monomer (a2) may contain two or more kinds of compounds containing different anionic functional groups. That is, the copolymer (A) may contain two or more structural units containing different anionic functional groups.
  • Examples of the monomer (a2) include unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid; half esters of unsaturated dicarboxylic acids; parastyrene. Examples include sulfonic acid.
  • the monomer (a2) preferably contains at least one of (meth) acrylic acid and itaconic acid.
  • At least a part of the structural unit derived from the monomer (a2) may form a salt with a basic substance.
  • examples of the monomer (a2) forming the salt include sodium (meth) acrylate, sodium parastyrene sulfonate, and the like.
  • the monomer (a2) preferably contains at least one of a sulfonic acid having an ethylenically unsaturated bond and a salt thereof, and more preferably contains a sulfonic acid salt having an ethylenically unsaturated bond.
  • the sulfonic acid preferably contains an aromatic vinyl compound having a sulfo group, and more preferably contains parastyrene sulfonic acid.
  • the sulfonate preferably contains a salt of an aromatic vinyl compound having a sulfo group, more preferably contains a parastyrene sulfonate, and even more preferably contains sodium parastyrene sulfonate. This is because the generation of coarse particles can be suppressed in the electrode binder composition described later.
  • the internal cross-linking agent (a3) is a compound having a plurality of independent ethylenically unsaturated bonds and capable of forming a cross-linked structure by radical polymerization of a monomer containing the monomers (a1) and (a2).
  • Examples of such a compound include divinylbenzene, ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate and the like.
  • the other monomer (a4) does not correspond to any of the monomers (a1) to (a3).
  • Examples of the other monomer (a4) include a compound having an ethylenically unsaturated bond and a polar functional group, and a surfactant having an ethylenically unsaturated bond (hereinafter, may be referred to as "polymerizable surfactant").
  • polymerizable surfactant a surfactant having an ethylenically unsaturated bond
  • Compounds having an ethylenically unsaturated bond and having a function as a silane coupling agent, and the like are not limited thereto.
  • the polar functional group preferably contains at least one of a hydroxy group and a cyano group.
  • the monomer having an ethylenically unsaturated bond and a polar functional group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl acrylate, and (meth) acrylonitrile.
  • the copolymer (A) preferably contains a structural unit derived from an ethylenically unsaturated bond and a compound containing a hydroxy group, and more preferably has a structural unit derived from a (meth) acrylate having a hydroxy group. It is more preferable to contain a structural unit derived from 2-hydroxyethyl (meth) acrylate.
  • Examples of the polymerizable surfactant include compounds having an ethylenically unsaturated bond and having a function as a surfactant, and examples thereof include compounds represented by the following chemical formulas (6) to (9). ..
  • R 3 is preferably an alkyl group, and p is preferably an integer of 10 to 40. It is more preferable that R 3 has 10 to 40 carbon atoms, and it is further preferable that R 3 is a linear unsubstituted alkyl group having 10 to 40 carbon atoms.
  • R 4 is preferably an alkyl group, and q is preferably an integer of 10 to 12. It is more preferable that R 4 has 10 to 40 carbon atoms, and it is further preferable that R 4 is a linear unsubstituted alkyl group having 10 to 40 carbon atoms.
  • R 5 is preferably an alkyl group, and M 1 is preferably NH 4 or Na. It is more preferable that R 5 has 10 to 40 carbon atoms, and it is further preferable that R 5 is a linear unsubstituted alkyl group having 10 to 40 carbon atoms.
  • R 6 is preferably an alkyl group, and M 2 is preferably NH 4 or Na. It is more preferable that R 6 has 10 to 40 carbon atoms, and it is further preferable that R 6 is a linear unsubstituted alkyl group having 10 to 40 carbon atoms.
  • Examples of the compound having an ethylenically unsaturated bond and having a function as a silane coupling agent include vinyltrimethoxysilane, ⁇ -methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, and ⁇ -methacryloxypropyltriethoxysilane. And so on.
  • the content of the 12th structural unit derived from the monomer (a2) is 1.0 part by mass or more with respect to 100 parts by mass of the 11th structural unit derived from the monomer (a1). It is preferably 2.0 parts by mass or more, and more preferably 3.5 parts by mass or more. This is because the mechanical stability of the electrode binder is improved. This is also because the peel strength of the electrode active material layer containing the electrode binder according to the present invention is improved.
  • the content of the 12th structural unit derived from the monomer (a2) is 30 parts by mass or less with respect to 100 parts by mass of the 11th structural unit derived from the monomer (a1). , 15 parts by mass or less, more preferably 7.5 parts by mass or less. This is to suppress gelation of the electrode binder. This is also because the mechanical stability of the electrode binder is improved.
  • the mass ratio of the 11th structural unit and the 12th structural unit to the copolymer (A) is preferably 80% by mass or more, more preferably 85% by mass or more, and 90% by mass or more in total. It is more preferable to have. This is because the effect obtained by the present invention is further enhanced by increasing the content of these structural units.
  • the internal cross-linking agent (a3) has a portion of 100 parts by mass of the eleventh structural unit derived from the monomer (a1).
  • the content of the derived 13th structural unit is 0 parts by mass or more, preferably 0.050 parts by mass or more, more preferably 0.075 parts by mass or more, and 0.50 parts by mass or more. It is more preferable to have. This is because the deterioration of the electrode binder can be suppressed, and the cycle characteristics (discharge capacity retention rate) of the battery using the electrode having the electrode active material layer containing the electrode binder according to the present invention can be improved.
  • the copolymer (A) contains a structural unit derived from the internal cross-linking agent (a3), it is derived from the internal cross-linking agent (a3) with respect to 100 parts by mass of the 11th structural unit derived from the monomer (a1).
  • the content of the thirteenth structural unit is 20 parts by mass or less, preferably 7.5 parts by mass or less, and more preferably 2.5 parts by mass or less. This is to suppress gelation of the electrode binder.
  • the glass transition point Tg of the copolymer (A) is obtained as a temperature differential of DSC by performing DSC measurement in a nitrogen gas atmosphere at a heating rate of 10 ° C./min using EXSTAR DSC / SS7020 manufactured by Hitachi High-Tech Science. The peak top temperature of the DDSC chart.
  • the glass transition point Tg of the copolymer (A) is preferably ⁇ 30 ° C. or higher, more preferably ⁇ 10 ° C. or higher, and even more preferably 0 ° C. or higher. This is because the cycle characteristics of the non-aqueous secondary battery including the electrode binder according to the present invention are improved.
  • the glass transition point Tg of the copolymer (A) is preferably 100 ° C. or lower, more preferably 50 ° C. or lower, and even more preferably 30 ° C. or lower. This is because the adhesion of the electrode active material layer containing the electrode binder according to the present invention to the current collector foil is improved.
  • the copolymer (A) can be obtained by copolymerizing a monomer containing the monomers (a1) and (a2). As the monomer, an internal cross-linking agent (a3) and another monomer (a4) may be copolymerized, if necessary.
  • the monomers used for synthesizing the copolymer (A) may be collectively referred to as the monomer (a).
  • Examples of the polymerization method include emulsion polymerization of the monomer (a) in the aqueous medium (b).
  • components used in the synthesis of the copolymer (A) by emulsion polymerization include, for example, a non-polymerizable surfactant (c), a basic substance (d), a radical polymerization initiator (e), and the like. Examples thereof include a chain transfer agent (f).
  • the aqueous medium (b) is water, a hydrophilic solvent, or a mixture thereof.
  • the hydrophilic solvent include methanol, ethanol, isopropyl alcohol, N-methylpyrrolidone and the like.
  • the aqueous medium (b) is preferably water.
  • a water to which a hydrophilic solvent is added may be used as long as the polymerization stability is not impaired.
  • a surfactant (c) that does not have polymerizability and does not correspond to the copolymer (B) described later may be used.
  • the surfactant (c) can improve the dispersion stability of the dispersion liquid (emulsion) during and / or after the polymerization.
  • anionic surfactant examples include an alkylbenzene sulfonate, an alkyl sulfate ester salt, a polyoxyethylene alkyl ether sulfate ester salt, and a fatty acid salt.
  • nonionic surfactant examples include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polycyclic phenyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, and polyoxyethylene sorbitan fatty acid ester.
  • the above-mentioned surfactant may be used alone or in combination of two or more.
  • the basic substance (d) may be added.
  • the acidic component contained in the monomer (a) can be neutralized and the pH can be adjusted.
  • the pH By adjusting the pH, the mechanical stability and chemical stability of the dispersion during and / or after emulsion polymerization can be improved.
  • the pH of the dispersion liquid at 23 ° C. may be appropriately adjusted depending on the specifications of the electrodes, the conditions for preparing the slurry described later, and the like, and is not limited, but is preferably 1.5 to 10, preferably 6.0 to 9. It is more preferably 0, and even more preferably 5.0 to 9.0. This is to suppress the sedimentation of the active material in the electrode slurry described later.
  • Examples of the basic substance (d) include ammonia, triethylamine, sodium hydroxide, lithium hydroxide and the like. These basic substances (d) may be used alone or in combination of two or more.
  • the radical polymerization initiator (e) used in the emulsion polymerization is not particularly limited, and known ones can be used.
  • the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate; hydrogen peroxide; azo compounds; organic peroxides such as t-butylhydroperoxide, tert-butylperoxybenzoate and cumenehydroperoxide. Examples include oxides. Of these, persulfates and organic peroxides are preferable.
  • a radical polymerization initiator and a reducing agent such as sodium bisulfite, longalit, and ascorbic acid may be used in combination during emulsion polymerization for redox polymerization.
  • the amount of the radical polymerization initiator added is preferably 0.10 part by mass or more, and more preferably 0.80 part by mass or more with respect to 100 parts by mass of the monomer (a). This is because the conversion rate of the monomer (a) to the copolymer (A) at the time of polymerization can be increased.
  • the amount of the radical polymerization initiator added is preferably 3.0 parts by mass or less, and more preferably 2.0 parts by mass or less with respect to 100 parts by mass of the monomer (a). This is because the molecular weight of the copolymer (A) can be increased and the swelling rate of the electrode active material layer with respect to the electrolytic solution can be reduced.
  • the chain transfer agent (f) is used to adjust the molecular weight of the copolymer (A) in emulsion polymerization.
  • the chain transfer agent (f) include n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, 2-ethylhexylthioglycolate, 2-mercaptoethanol, ⁇ -mercaptopropionic acid, methyl alcohol, and n-propyl alcohol. Examples thereof include isopropyl alcohol, t-butyl alcohol and benzyl alcohol.
  • Examples of the emulsion polymerization method include a method of emulsion polymerization while continuously supplying each component used for emulsion polymerization.
  • the temperature of the emulsion polymerization is not particularly limited, but is, for example, 30 to 90 ° C, preferably 50 to 85 ° C, and even more preferably 55 to 80 ° C.
  • Emulsion polymerization is preferably carried out with stirring. Further, it is preferable that the monomer (a) and the radical polymerization initiator are continuously supplied so as to be uniform in the reaction vessel.
  • the copolymer (B) has a 21st structural unit represented by the following formula (1), a 22nd structural unit represented by the following formula (2), and a 23rd structure represented by the following formula (3). It has a unit and.
  • the copolymer (B) preferably has a plurality of ethylenically unsaturated bonds in one molecule.
  • the copolymer (B) may contain a structural unit that does not fall under any of the 21st structural unit, the 22nd structural unit, and the 23rd structural unit.
  • the terminal structure is not considered unless otherwise specified when describing the structure of the structural unit.
  • the content of a certain structural unit in the copolymer (B) is the content of the structural unit in the structure excluding the terminal structure unless otherwise specified.
  • the copolymer (B) when the copolymer (B) is composed of a certain structural unit, it may contain a terminal structure in addition to the structural unit.
  • the terminal structure in the copolymer (B) is on the molecular terminal side of the ether bond closest to the molecular terminal, and is not included in any of the structures of the following formulas (1) to (3). It is a structure. Further, the terminal structure does not include the structures represented by the following formulas (1) to (3).
  • R 1 is an alkyl group having 1 or more and 6 or less carbon atoms which may have a branch.
  • R 1 preferably has 4 or less carbon atoms, more preferably 2 or less carbon atoms, and even more preferably a methyl group.
  • R 2 is a group having an ethylenically unsaturated bond.
  • the number of ethylenically unsaturated bonds contained in one 23rd structural unit is preferably one.
  • R2 is preferably represented by the following formula (4).
  • R 21 is an alkylene group having 1 to 5 carbon atoms which may have a branch
  • R 22 is a vinyloxy group, an allyloxy group, a (meth) acryloyl group, a (meth) acryloyloxy group, and-.
  • OCH 2 -CH 2 -CH 2 CH 2 is any one of them.
  • R 21 is preferably an alkylene group having 1 or 2 carbon atoms, and more preferably a methylene group.
  • R 22 is more preferably any one of an allyloxy group, a (meth) acryloyl group, and a (meth) acryloyloxy group, and even more preferably an allyloxy group.
  • the hydrophilicity of the copolymer (B) can be controlled in an appropriate range. For example, if the content of the 21st structural unit in the copolymer (B) is increased, the hydrophilicity of the copolymer (B) is improved, and if the content of the 21st structural unit is decreased, the copolymer (B) is used. The hydrophilicity of is reduced.
  • the crystallinity of the copolymer (B) can be adjusted to an appropriate range, and the copolymer (B) can be adjusted. Crystallinity can be controlled. For example, if the content of the 21st structural unit in the copolymer (B) is increased, the crystallinity of the copolymer (B) is improved, and if the content of the 21st structural unit is decreased, the copolymer (B) is used. Crystallinity is reduced.
  • the content of the 21st structural unit in the total structural units is 5.0 mol% or more, preferably 18 mol% or more, and preferably 25 mol% or more. More preferred. In the copolymer (B), the content of the 21st structural unit in the total structural units is 98 mol% or less, preferably 97 mol% or less.
  • the content of the 22nd structural unit in all the structural units is 0.30 mol% or more, preferably 0.50 mol% or more, preferably 0.70 mol% or more. Is more preferable.
  • the content of the 22nd structural unit in the total structural units is 90 mol% or less, preferably 80 mol% or less, and more preferably 75 mol% or less. ..
  • the content of the 23rd structural unit in all the structural units is 0.30 mol% or more, preferably 0.50 mol% or more, preferably 0.70 mol% or more. Is more preferable.
  • the content of the 23rd structural unit in the total structural units is 10 mol% or less, preferably 6.0 mol% or less, and preferably 4.5 mol% or less. Is more preferable.
  • the total content of the 21st structural unit, the 22nd structural unit, and the 23rd structural unit in the total structural unit of the copolymer (B) is 90% by mass or more, and 95% by mass or more. It is more preferably 98% by mass or more, and most preferably 100% by mass.
  • the structural unit constituting the copolymer (B) does not include the terminal structure (definition is as described above). The same applies to the copolymer (B1) according to the first form and the copolymer (B2) according to the second form described below.
  • copolymer (B) examples include the following two preferable forms having different hydrophilicity. Hereinafter, these forms will be described as the copolymer (B1) according to the first form and the copolymer (B2) according to the second form.
  • the copolymer (B2) according to the second form is more hydrophilic than the copolymer (B1) according to the first form.
  • the content of the 21st structural unit in the total structural units is preferably 5.0 mol% or more, more preferably 18 mol% or more, and 25 mol% or more. Is more preferable.
  • the content of the 21st structural unit in the total structural units is preferably 50 mol% or less, more preferably 40 mol% or less.
  • the content of the 22nd structural unit in the total structural units is preferably 40 mol% or more, more preferably 50 mol% or more, and more preferably 60 mol% or more. Is even more preferable.
  • the content of the 22nd structural unit in the total structural units is preferably 90 mol% or less, more preferably 80 mol% or less, and 75 mol% or less. Is even more preferable.
  • the content of the 23rd structural unit in all the structural units is preferably 0.30 mol% or more, more preferably 0.50 mol% or more, and 0. It is more preferably 70 mol% or more.
  • the content of the 23rd structural unit in the total structural units is preferably 10 mol% or less, more preferably 6.0 mol% or less, and 4.5 mol. It is more preferably% or less.
  • the content of the 21st structural unit in the total structural units is preferably 70 mol% or more, more preferably 80 mol% or more, and more preferably 90 mol% or more. Is even more preferable.
  • the content of the 21st structural unit in the total structural units is preferably 98 mol% or less, more preferably 97 mol% or less.
  • the content of the 22nd structural unit in the total structural units is preferably 0.30 mol% or more, more preferably 0.50 mol% or more, and 0. It is more preferably 70 mol% or more.
  • the content of the 22nd structural unit in the total structural units is preferably 20 mol% or less, more preferably 15 mol% or less, and 10 mol% or less. Is even more preferable.
  • the content of the 23rd structural unit in the total structural units is preferably 0.30 mol% or more, more preferably 0.50 mol% or more, and 0. It is more preferably 70 mol% or more.
  • the content of the 23rd structural unit in the total structural units is preferably 10 mol% or less, more preferably 6.0 mol% or less, and 4.5 mol. It is more preferably% or less.
  • the copolymer (B) is preferably a block copolymer having a first block composed of the 21st structural unit, a second block composed of the 22nd structural unit, and a third block composed of the 23rd structural unit.
  • the copolymer (B) is more preferably a ternary block copolymer composed of a first block, a second block, and a third block (however, the terminal structure may be included as defined above).
  • the copolymer (B) is a ternary in which the first block, the second block, and the third block are arranged in that order (that is, the second block exists between the first block and the third block). It is more preferably a block copolymer.
  • the preferred range of the weight average molecular weight of the copolymer (B) depends on the presence or absence of water solubility of the copolymer (B).
  • the weight average of the copolymer (B) is a pull-run conversion value measured by an aqueous GPC under the conditions shown below.
  • the weight average molecular weight M w (pullulan equivalent value) of the copolymer (B) is preferably 10,000 or more, more preferably 30,000 or more, and further preferably 50,000 or more. This is because the strength of the electrode is improved. Further, in this case, the weight average molecular weight M w (pullulan equivalent value) of the copolymer (B) is preferably 300,000 or less, more preferably 200,000 or less, and further preferably 120,000 or less. This is because the dispersibility of the solid content in the electrode slurry described later is improved.
  • the copolymer (B) When it is impossible to dissolve the copolymer (B) in a 0.1 M NaNO 3 aqueous solution to prepare an aqueous solution containing 0.1% by mass of the copolymer (B), the copolymer (B) is used.
  • the weight average molecular weight of the above is a polystyrene-equivalent value measured by a solvent-based GPC under the conditions shown below.
  • the weight average molecular weight M w (polystyrene equivalent value) of the copolymer (B) is preferably 10,000 or more, more preferably 20,000 or more, and further preferably 30,000 or more. This is because the strength of the electrode is improved. Further, in this case, the weight average molecular weight M w (polystyrene equivalent value) of the copolymer (B) is preferably 200,000 or less, more preferably 150,000 or less, and further preferably 80,000 or less. This is because the dispersibility of the solid content in the electrode slurry described later is improved.
  • copolymer (B) is preferably, for example, a ternary block copolymer represented by the following formula (5).
  • n: m: l 5.0 to 98: 0.30 to 90: 0.30 to 4.5
  • n: m: l 18 to 97: 0.50 to 80: 0.
  • the preferred range of weight average molecular weight is as described above.
  • the weight average molecular weight is 10,000 to 200,000 in terms of polystyrene. It is preferably 20,000 to 150,000, more preferably 30,000 to 80,000.
  • the weight average molecular weight is 10,000 to 300,000 in terms of pullulan, which is 30,000. It is preferably about 200,000, more preferably 50,000 to 120,000.
  • the method for synthesizing the copolymer (B) is not particularly limited, but it can be obtained, for example, by ring-opening polymerization of the epoxide using an acid catalyst. Further, trialkylaluminum, hydroxide, alkali metal alkoxide and the like may be used as the catalyst.
  • the copolymer (B) is used as a block copolymer, it is preferable to polymerize the monomers corresponding to the respective structural units one by one in order. In this case, it is preferable that the order of polymerization corresponds to a desired sequence.
  • the polymerization is preferably carried out in an aqueous medium, and the aqueous medium that can be used is the same as the aqueous medium (b) described above, but may be different from the aqueous medium used for synthesizing the copolymer (A). good.
  • the mass ratio of the copolymer (A) to the copolymer (B) is 50.0 / 50.0 or more. It is preferably 53.0 / 47.0 or more, more preferably 64.0 / 36.0 or more, and even more preferably 77.0 / 23.0 or more. This is because the peel strength of the electrode active material layer containing the electrode binder according to the present invention to the current collector is improved. Further, this is because the cycle characteristics of the non-aqueous secondary battery provided with the electrode active material layer on the electrode are improved.
  • the mass ratio of the copolymer (A) to the copolymer (B) is 99.0 / 1.0 or less. It is preferably 97.5 / 2.5 or less, more preferably 96.5 / 3.5 or less, and further preferably 93.0 / 7.0 or less. This is because the internal resistance of the non-aqueous secondary battery provided with the electrode active material layer containing the electrode binder according to the present invention is reduced, and the cycle characteristics of the non-aqueous secondary battery are improved. Further, when the internal resistance of the non-aqueous secondary battery is further reduced, the mass ratio is more preferably 88.0 / 12.0 or less.
  • Non-aqueous secondary battery electrode binder composition includes an electrode binder containing the copolymer (A) and the copolymer (B), and an aqueous medium (C). ) And.
  • the non-aqueous secondary battery electrode binder composition of the present embodiment is the binder composition for the non-aqueous secondary battery electrode of the present embodiment.
  • the copolymer (A) is preferably dispersed in the aqueous medium (C).
  • the copolymer (B) may be dispersed or dissolved in the aqueous medium (C).
  • the binder composition includes, for example, a component used for producing the electrode binder according to the present invention, a binder other than the electrode binder according to the present invention, and a copolymer (B) as well as the copolymer (A). ) May also be contained, such as a polymer and a surfactant.
  • the aqueous medium (C) is the same as the aqueous medium (b) described above, but is different from the aqueous medium used for the synthesis of the copolymer (A) and the aqueous medium used for the synthesis of the copolymer (B). May be.
  • the content of the electrode binder according to the present invention in the non-volatile content in the binder composition is preferably 80% by mass or more, more preferably 90% by mass or more, and more preferably 95% by mass or more. It is more preferably 98% by mass or more, and even more preferably 98% by mass or more. This is to increase the contribution of the electrode binder to the desired effect of the present invention.
  • the non-volatile content concentration of the binder composition is preferably 20% by mass or more, more preferably 25% by mass or more, and further preferably 30% by mass or more. This is to increase the amount of the active ingredient contained in the binder composition.
  • the non-volatile content concentration of the binder composition can be adjusted by the amount of the aqueous medium (C).
  • the non-volatile content concentration of the binder composition is preferably 80% by mass or less, more preferably 70% by mass or less, and further preferably 60% by mass or less. This is to suppress an increase in the viscosity of the binder composition and facilitate the production of a slurry described later.
  • a method for producing a binder composition a method of mixing a mixed solution containing the copolymer (A) and a mixed solution containing the copolymer (B) and adding other components as necessary is used. Can be mentioned.
  • the method for producing the binder composition one of the copolymer (A) and the copolymer (B) is added as a mixed solution, and the other is added as a solid such as powder, and if necessary, the other. Examples include a method of adding an ingredient.
  • the copolymer (A) and the copolymer (B) are mixed as a solid, added to the aqueous medium (C), and if necessary, other components are added. The method can be mentioned.
  • the method for producing the binder composition is not limited to the examples given here.
  • the non-aqueous secondary battery electrode slurry is a slurry for a non-aqueous secondary battery electrode.
  • the electrode slurry includes an electrode binder according to the present invention, an electrode active material, and an aqueous medium.
  • the copolymer (A) is preferably dispersed in an aqueous medium.
  • the copolymer (B) may be dispersed or dissolved in an aqueous medium.
  • the electrode slurry can also be used as a thickener, a conductive auxiliary agent, a component used for producing the electrode binder according to the present invention, a binder other than the electrode binder according to the present invention, and a copolymer (A).
  • a polymer, a surfactant, or the like that does not correspond to the copolymer (B) may be contained.
  • Electrode binder content The content of the electrode binder is preferably 0.50 part by mass or more, and more preferably 1.0 part by mass or more with respect to 100 parts by mass of the electrode active material. This is to fully exhibit the effect of the electrode binder.
  • the content of the electrode binder is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and 3.0 parts by mass or less with respect to 100 parts by mass of the electrode active material. Is even more preferable. This is to increase the content of the electrode active material in the electrode active material layer produced by using the electrode slurry.
  • the electrode active material is a material capable of intercalation / deintercalation of ions that become charge carriers such as lithium ions.
  • the ion serving as a charge carrier is preferably an alkali metal ion, more preferably a lithium ion, a sodium ion, or a potassium ion, and even more preferably a lithium ion.
  • the electrode active material that is, the negative electrode active material preferably contains at least one of a carbon material, a material containing silicon, and a material containing titanium.
  • the carbon material used as the electrode active material include coke such as petroleum coke, pitch coke, and coal coke, carbonized organic polymer, artificial graphite, and graphite such as natural graphite.
  • the material containing silicon include a simple substance of silicon and a silicon compound such as silicon oxide.
  • the material containing titanium include lithium titanate and the like. These materials may be used alone, or may be mixed or combined.
  • the negative electrode active material preferably contains at least one of a carbon material and a material containing silicon, and more preferably contains a carbon material. This is because the effect of the electrode binder on improving the binding property between the electrode active materials and between the electrode active material and the current collector is very large.
  • the electrode active material uses a material having a higher standard electrode potential than the negative electrode active material.
  • a lithium composite oxide containing nickel such as a Ni—Co—Mn-based lithium composite oxide, a Ni—Mn—Al based lithium composite oxide, and a Ni—Co—Al based lithium composite oxide.
  • these substances may be used alone or in combination of two or more.
  • thickener examples include celluloses such as carboxymethyl cellulose (CMC), hydroxyethyl cellulose and hydroxypropyl cellulose, ammonium salts of celluloses, alkali metal salts of celluloses, polyvinyl alcohol, polyvinylpyrrolidone and the like.
  • the thickener preferably contains at least one of carboxymethyl cellulose, an ammonium salt of carboxymethyl cellulose, and an alkali metal salt of carboxymethyl cellulose. This is because the electrode active material is easily dispersed in the electrode slurry.
  • the content of the thickener in the electrode slurry is preferably 0.50 part by mass or more, and more preferably 0.80 part by mass or more with respect to 100 parts by mass of the electrode active material. This is to improve the bondability between the electrode active materials and between the electrode active material and the current collector in the electrode active material layer produced by using the electrode slurry.
  • the content of the thickener in the electrode slurry is preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, and 1.5 parts by mass with respect to 100 parts by mass of the electrode active material. The following is more preferable. This is because the coatability of the electrode slurry is improved.
  • the aqueous medium is the same as the aqueous medium (b) described above, but may be different from the aqueous medium used for the synthesis of the copolymer (A) and the aqueous medium used for the synthesis of the copolymer (B). good.
  • the conductive auxiliary agent it is preferable to use carbon black, carbon fiber or the like.
  • carbon black include furnace black, acetylene black, denka black (registered trademark, manufactured by Denka Co., Ltd.), and Ketjen black (registered trademark, manufactured by Ketjen Black International Co., Ltd.).
  • the carbon fiber include carbon nanotubes and carbon nanofibers, and examples of the carbon nanotube include VGCF (registered trademark, manufactured by Showa Denko Co., Ltd.), which is a vapor phase carbon fiber.
  • the non-volatile content concentration of the electrode slurry is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more. This is because the concentration of the active ingredient in the electrode slurry becomes high, and a sufficient amount of the electrode active material layer can be formed with a small amount of the electrode slurry.
  • the non-volatile content concentration of the electrode slurry can be adjusted by adjusting the amount of the aqueous medium in the electrode slurry.
  • the non-volatile content concentration of the electrode slurry is preferably 85% by mass or less, more preferably 75% by mass or less, and further preferably 65% by mass or less. This is to maintain good coatability of the electrode slurry.
  • the viscosity of the electrode slurry is preferably 20000 mPa ⁇ s or less, more preferably 10,000 mPa ⁇ s or less, and further preferably 5000 mPa ⁇ s or less. This is because the applicability of the electrode slurry to the current collector is improved and the productivity of the electrodes is improved.
  • the viscosity of the electrode slurry is greatly affected by the non-volatile content concentration of the electrode slurry and the type and amount of the thickener.
  • the pH of the electrode slurry at 23 ° C. may be appropriately adjusted depending on the specifications of the electrode, the production conditions, and the like, and is not limited, but is preferably 2.0 to 10, and more preferably 4.0 to 9.0. , More preferably 6.0 to 9.0. This is to improve the durability of the battery manufactured by using the electrode slurry.
  • Methods for preparing the electrode slurry include a binder composition, an electrode active material, a thickener if necessary, an aqueous medium if necessary, a conductive auxiliary agent if necessary, and others if necessary.
  • a method of mixing with the components of the above can be mentioned, but the method is not limited to this method.
  • the order of the components to be added is not particularly limited and may be appropriately determined.
  • Examples of the mixing method include a method using a mixing device such as a stirring type, a rotary type, and a shaking type.
  • Non-aqueous secondary battery electrode includes a current collector and an electrode active material layer formed on the current collector.
  • Examples of the shape of the electrode include a laminated body and a wound body, but the shape is not particularly limited. Further, the range of forming the electrode active material layer on the current collector is not particularly limited, and it may be formed on the entire surface of the current collector or may be formed on a part of the surface of the current collector. When the current collector is in the shape of a plate, foil, or the like, the electrode active material layer may be formed on both sides of the current collector, or may be formed on only one side.
  • the current collector is preferably a metal sheet having a thickness of 0.001 mm or more and 0.5 mm or less, and examples of the metal include iron, copper, aluminum, nickel, and stainless steel.
  • the current collector is preferably a copper foil.
  • the electrode active material layer includes an electrode binder and an electrode active material.
  • the electrode active material layer may contain a conductive auxiliary agent, a thickener and the like. The components listed here are as described above.
  • Electrode manufacturing method As a method for manufacturing an electrode, for example, an electrode slurry is applied onto a current collector, dried to form an electrode active material layer, and then cut into an appropriate size.
  • the method of applying the electrode slurry onto the current collector is not particularly limited, but for example, the reverse roll method, the direct roll method, the doctor blade method, the knife method, the extrusion method, the curtain method, the gravure method, the bar method, and the dip method. Law, squeeze method, etc. can be mentioned.
  • the doctor blade method, the knife method, or the extrusion method is preferably used in consideration of various physical properties such as the viscosity of the electrode slurry and the drying property. This is because it is possible to obtain an electrode active material layer having a smooth surface and a small variation in thickness.
  • the electrode slurry may be applied to only one side of the current collector or may be applied to both sides. When the electrode slurry is applied to both sides of the current collector, it may be applied sequentially on one side at a time or on both sides at the same time. Further, the electrode slurry may be continuously applied to the current collector or may be applied intermittently.
  • the coating amount of the electrode slurry can be appropriately determined according to the design capacity of the battery, the composition of the electrode slurry, and the like. The coating amount of the electrode slurry depends on the properties of the electrode slurry, but is preferably 13 mg / cm 2 or less (when coated on both sides, the coating amount per one side). This is because the occurrence of cracks on the electrode surface can be suppressed in the process of drying the electrode slurry.
  • an electrode active material layer is formed on the current collector.
  • the method for drying the electrode slurry is not particularly limited, and for example, hot air, reduced pressure or vacuum environment, (far) infrared rays, and low temperature air can be used alone or in combination.
  • the drying temperature and drying time of the electrode slurry can be appropriately adjusted depending on the concentration of the non-volatile content in the electrode slurry, the amount of coating on the current collector, and the like.
  • the drying temperature is preferably 40 ° C. or higher and 350 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower from the viewpoint of productivity.
  • the drying time is preferably 1 minute or more and 30 minutes or less.
  • the electrode sheet on which the electrode active material layer is formed on the current collector may be cut in order to obtain an appropriate size and shape as an electrode.
  • the method for cutting the electrode sheet is not particularly limited, but for example, a slit, a laser, a wire cut, a cutter, a Thomson, or the like can be used.
  • the electrode sheet may be pressed as needed before or after cutting the electrode sheet.
  • the electrode active material is firmly bound to the current collector, and the electrode can be made thinner, so that the non-aqueous battery can be miniaturized.
  • a pressing method a general method can be used, and it is particularly preferable to use a die pressing method or a roll pressing method.
  • the pressing pressure is not particularly limited, but is preferably 0.5 t / cm 2 or more and 5 t / cm 2 or less.
  • the linear pressure is not particularly limited, but is preferably 0.5 t / cm or more and 5 t / cm or less. This is to suppress the insertion of charge carriers such as lithium ions into the electrode active material and the decrease in the desorption capacity while obtaining the above effects by the press.
  • Non-water-based secondary battery > A lithium ion secondary battery will be described as a preferred example of the non-aqueous secondary battery according to the present embodiment, but the battery configuration is not limited to that described here.
  • the non-aqueous secondary battery according to the present embodiment has a positive electrode, a negative electrode, an electrolytic solution, and, if necessary, a component such as a separator, housed in an exterior body, and is one of a positive electrode and a negative electrode. Alternatively, the electrodes produced by the above method are used for both.
  • at least one of the positive electrode and the negative electrode contains the electrode binder according to the present invention, but it is preferable that at least the negative electrode contains the electrode binder according to the present invention.
  • Electrolyte As the electrolytic solution, a non-aqueous liquid having ionic conductivity is used.
  • the electrolytic solution include a solution in which an electrolyte is dissolved in an organic solvent, an ionic liquid, and the like, and the former is preferable. This is because a non-aqueous battery having a low manufacturing cost and a low internal resistance can be obtained.
  • an alkali metal salt can be used and can be appropriately selected depending on the type of the electrode active material and the like.
  • the electrolyte include LiClO 4 , LiBF 6 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiB 10 Cl 10 , LiAlCl 4 , LiCl, LiBr, LiB (C2H 5 ). 4 , CF 3 SO 3 Li, CH 3 SO 3 Li, LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 N, lithium aliphatic carboxylate and the like can be mentioned. Further, other alkali metal salts can also be used as the electrolyte.
  • the organic solvent that dissolves the electrolyte is not particularly limited, and is, for example, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), dimethyl carbonate (DMC), and fluoroethylene carbonate.
  • EC ethylene carbonate
  • PC propylene carbonate
  • DEC diethyl carbonate
  • MEC methyl ethyl carbonate
  • DMC dimethyl carbonate
  • FEC fluoroethylene carbonate
  • carbonic acid ester compounds such as vinylene carbonate (VC)
  • nitrile compounds such as acetonitrile Ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate and other carboxylic acid esters can be mentioned.
  • These organic solvents may be used alone or in combination of two or more. Above all, it is preferable to use a combination of a linear carbonate solvent.
  • the exterior body for example, a laminated material of an aluminum foil and a resin film can be appropriately used, but the exterior body is not limited to this.
  • the shape of the battery may be any shape such as a coin type, a button type, a sheet type, a cylindrical type, a square type, and a flat type.
  • a negative electrode of a lithium ion secondary battery and a lithium ion secondary battery are manufactured, and the negative electrode of the lithium ion secondary battery and the lithium ion secondary battery according to the comparative example are used.
  • the effect of the present invention is confirmed.
  • the present invention is not limited thereto.
  • the water used in the following Examples and Comparative Examples is ion-exchanged water.
  • the content of the copolymer (A) or the copolymer (CA) in the aqueous dispersion was adjusted to 40% by mass.
  • a polyoxyethylene alkyl ether sulfate ester salt manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., High Tenor 08E
  • the surfactant is contained in an amount of 0.20 parts by mass with respect to 100 parts by mass of the copolymer (A) or the copolymer (CA).
  • the obtained film was cut into 2 mm ⁇ 2 mm, sealed in an aluminum pan, and DSC measurement was performed using EXSTAR DSC / SS7020 manufactured by Hitachi High-Tech Science Co., Ltd. at a heating rate of 10 ° C./min in a nitrogen gas atmosphere.
  • the peak top temperature of the DDSC chart obtained as the temperature differential of DSC was measured, and this temperature was defined as the glass transition point Tg (° C.) of the copolymer (P) and the copolymer (CP).
  • the measurement temperature range was ⁇ 40 ° C. to 200 ° C.
  • the measured glass transition point values are shown in Table 1.
  • the dispersion liquid of the copolymer (A) or the copolymer (CA) and the dispersion liquid or the aqueous solution of the copolymer (B) were mixed.
  • the ratios of the copolymer (A) or the copolymer (CA) and the copolymer (B) are shown in Tables 4 and 5 (comparing the differences in conditions).
  • the mass ratio of Example 1 was set to the mass ratio shown in both Table 4 and Table 5).
  • the non-volatile content concentration (mass%) of the binder compositions obtained in Examples and Comparative Examples was measured by the following method. The measurement results are shown in Tables 4 and 5.
  • the positive electrode slurry was applied to both sides of an aluminum foil (positive electrode current collector) having a thickness of 15 ⁇ m by the direct roll method.
  • the amount of the positive electrode slurry applied to the positive electrode current collector was adjusted so that the thickness after the roll press treatment described later was 125 ⁇ m per side.
  • the positive electrode slurry applied on the positive electrode current collector was dried at 120 ° C. for 5 minutes and pressed by a roll press (manufactured by Thunk Metal Co., Ltd., press load 5 tons, roll width 7 cm) to form a positive electrode active material layer.
  • a positive electrode sheet was obtained.
  • the obtained positive electrode sheet was cut out to a size of 50 mm ⁇ 40 mm, and a conductive tab was attached to prepare a positive electrode.
  • CMC Carboxymethyl Cellulose-Sodium Salt, Sunrose (Registered Trademark) MAC500LC manufactured by Nippon Paper Chemical Co., Ltd.
  • Negative electrode slurry was applied to both sides of a copper foil (negative electrode current collector) having a thickness of 10 ⁇ m by the direct roll method.
  • the amount of the negative electrode slurry applied to the negative electrode current collector was adjusted so that the thickness after the roll press treatment described later was 170 ⁇ m per side.
  • the negative electrode slurry applied on the negative electrode current collector is dried at 90 ° C. for 10 minutes, pressed by a roll press (manufactured by Thunk Metal, press load 8 t, roll width 7 cm), and the negative electrode active material layer is placed on the current collector.
  • a roll press manufactured by Thunk Metal, press load 8 t, roll width 7 cm
  • the negative electrode active material layer is placed on the current collector.
  • the obtained negative electrode sheet was cut out to a size of 52 mm ⁇ 42 mm, and a conductive tab was attached to prepare a negative electrode.
  • EC ethylene carbonate
  • EMC ethylmethyl carbonate
  • DEC diethyl carbonate
  • the negative electrode active material layer bonded to the SUS plate is peeled off by 20 mm in the length direction from one end of the test piece, and the test piece on the copper foil side is peeled off.
  • this portion was grasped by the chuck on the upper side of the testing machine. Further, one end of the SUS plate from which the negative electrode active material layer was peeled off was grasped by the lower chuck.
  • the copper foil was peeled off from the test piece at a speed of 100 ⁇ 10 mm / min, and a graph of peeling length (mm) -peeling force (mN) was obtained.
  • the average value (mN) of the peeling force at the peeling length of 10 to 45 mm was calculated, and the value obtained by dividing the average value of the peeling force by the width of the test piece of 25 mm was the peeling strength (mN / mN /) of the negative electrode active material layer. mm).
  • peeling between the double-sided tape and the SUS plate and interfacial peeling between the double-sided tape and the negative electrode active material layer did not occur during the test.
  • the time integral value of the current in the steps (i) and (ii) is the charge capacity
  • the time integral value of the current in the step (iv) is the discharge capacity.
  • the discharge capacity in the first cycle and the discharge capacity in the 100th cycle were measured.
  • 100 ⁇ (discharge capacity in the 100th cycle) / (discharge capacity in the first cycle) [%] was calculated as the cycle capacity retention rate under high temperature of the battery, and is shown in Tables 1 and 2.
  • Comparative Example 1 an electrode and a battery were produced using a binder composition containing no copolymer (B). However, the internal resistance of the battery could not be sufficiently reduced, and the discharge capacity retention rate was not sufficient.
  • Comparative Example 2 an electrode and a battery were prepared using a binder composition containing an excess of the copolymer (B). However, the peel strength of the negative electrode active material layer in the electrode was low. In addition, the discharge capacity retention rate of the battery was not sufficient.
  • a binder composition was prepared using a copolymer (CA-1) having no twelfth structural unit.
  • a binder composition was prepared using a copolymer (CA-2) having an excess of the twelfth structural unit.
  • a binder composition was prepared using a copolymer (CA-3) having an excess of the thirteenth structural unit.
  • the peel strength of the negative electrode active material layer in the electrode produced by using these binder compositions was low.
  • the internal resistance of the battery could not be sufficiently reduced, and the discharge capacity retention rate was not sufficient.
  • the peel strength of the electrode active material layer with respect to the current collector is effectively improved in the non-aqueous secondary battery, and the internal resistance of the battery is reduced. And it can be seen that it can contribute to the improvement of cycle characteristics.

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Abstract

Provided is a binder for non-aqueous secondary battery electrodes, that effectively improves peel strength from a current collector of an electrode active material layer and can contribute to a reduction in the internal resistance of a battery and an improvement in cycle characteristics. This binder for non-aqueous secondary battery electrodes includes a copolymer (A) and a copolymer (B). The copolymer (A) has 11th to 13th structural units that are derived from: monomers (a1), (a2) that have an ethylenically unsaturated bond; and an internal cross-linking agent (a3). The copolymer (B) has, among all structural units, 5.0–98 mol%, 0.30–90 mol%, and 0.30–10 mol%, respectively, of 21st to 23rd structural units indicated by formulas (1)–(3).　Chemical formula 1 (In formula (2), R1 indicates a C1–6 alkyl group that may be branched. In formula (3), R2 indicates a group having an ethylenically unsaturated bond.)

Description

非水系二次電池電極バインダー、非水系二次電池電極バインダー組成物、及び非水系二次電池電極Non-aqueous secondary battery electrode binder, non-aqueous secondary battery electrode binder composition, and non-aqueous secondary battery electrode
　本発明は、非水系二次電池電極バインダー、非水系二次電池電極バインダー組成物、及び非水系二次電池電極に関する。
　本願は、２０２０年１２月２４日に、日本に出願された特願２０２０－２１４８８２号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a non-aqueous secondary battery electrode binder, a non-aqueous secondary battery electrode binder composition, and a non-aqueous secondary battery electrode.
This application claims priority based on Japanese Patent Application No. 2020-214882 filed in Japan on December 24, 2020, the contents of which are incorporated herein by reference.
　非水系二次電池は、例えば、金属酸化物などを正極活物質とした正極と、黒鉛等の材料を負極活物質とした負極と、電解液とを含む。非水系二次電池は、電荷キャリアとなるイオンが正極と負極との間を移動することにより電池の充放電が行われる二次電池である。 The non-aqueous secondary battery includes, for example, a positive electrode using a metal oxide or the like as a positive electrode active material, a negative electrode using a material such as graphite as a negative electrode active material, and an electrolytic solution. A non-aqueous secondary battery is a secondary battery in which ions serving as charge carriers move between a positive electrode and a negative electrode to charge and discharge the battery.
　非水系二次電池としてリチウムイオン二次電池が代表例として挙げられる。非水系二次電池は、小型化、軽量化の面からノート型パソコン、携帯電話、電動工具、電子・通信機器の電源として使用されている。また、最近では環境車両適用の観点から電気自動車及びハイブリッド自動車等にも使用されている。その中で、非水系二次電池の高出力化、高容量化、長寿命化等が強く求められている。 A typical example is a lithium ion secondary battery as a non-aqueous secondary battery. Non-aqueous secondary batteries are used as power sources for notebook computers, mobile phones, power tools, and electronic / communication devices in terms of miniaturization and weight reduction. Recently, it has also been used in electric vehicles, hybrid vehicles, and the like from the viewpoint of application to environmental vehicles. Under these circumstances, there is a strong demand for higher output, higher capacity, longer life, etc. of non-aqueous secondary batteries.
　正極及び負極に使用されるバインダーには、電極活物質同士を結着させる役割、及び電極活物質と集電体とを結着させる役割がある。非水系二次電池の容量向上、作業環境保全のため、水分散系バインダーの開発が進められている。例えば、増粘剤としてカルボキシメチルセルロース（ＣＭＣ）を併用したスチレン－ブタジエンゴム（ＳＢＲ）系の水分散体が知られている。 The binder used for the positive electrode and the negative electrode has a role of binding the electrode active material to each other and a role of binding the electrode active material and the current collector. Water dispersion binders are being developed to improve the capacity of non-aqueous secondary batteries and protect the working environment. For example, a styrene-butadiene rubber (SBR) -based aqueous dispersion using carboxymethyl cellulose (CMC) as a thickener is known.
　特許文献１では、エチレンオキシドと、エチレンオキシド以外のアルキレンオキシド、アルキルグリシジルエーテル、アリルグリシジルエーテル又はそれらの組合せとを重合する方法が記載されている。重合して得られるコポリマーを含む組成物は、電気活性粒子を含む電池電極におけるバインダー材として使用することができることが記載されている。 Patent Document 1 describes a method for polymerizing ethylene oxide with an alkylene oxide other than ethylene oxide, an alkyl glycidyl ether, an allyl glycidyl ether, or a combination thereof. It is described that the composition containing the copolymer obtained by polymerization can be used as a binder material in a battery electrode containing electroactive particles.
　特許文献２では、（メタ）アクリル酸エステル及び酸成分を有するビニル単量体から得られる共重合体と；ポリオキシエチレンアルキルエーテル誘導体、ポリオキシエチレン－ポリオキシプロピレン縮合物、及びポリオキシエチレン－ポリオキシプロピレンアルキルエーテル誘導体からなる群より選択される少なくとも一種と；を含有する電極層を備えた二次電池負極が記載されている。 In Patent Document 2, a copolymer obtained from a (meth) acrylic acid ester and a vinyl monomer having an acid component; a polyoxyethylene alkyl ether derivative, a polyoxyethylene-polyoxypropylene condensate, and a polyoxyethylene- A secondary battery negative electrode comprising an electrode layer containing at least one selected from the group consisting of polyoxypropylene alkyl ether derivatives; is described.
特表２０１２－５１７５１９号公報Special Table 2012-517519 Gazette 特開２０１４－２３９０７０号公報Japanese Unexamined Patent Publication No. 2014-239070
　しかしながら、特許文献１及び２に記載の成分においては、電極用バインダーとして用いた場合に、電極活物質層の集電体に対する剥離強度の向上の余地、及び電池を作成した場合の内部抵抗の低減の余地がある。 However, in the components described in Patent Documents 1 and 2, when used as a binder for electrodes, there is room for improving the peel strength of the electrode active material layer with respect to the current collector, and the internal resistance is reduced when the battery is manufactured. There is room for.
　本発明は、非水系二次電池において電極活物質層の集電体に対する剥離強度を効果的に向上させ、電池の内部抵抗の低減及びサイクル特性の向上に貢献できる非水系二次電池電極バインダー、非水系二次電池電極バインダー組成物、及び非水系二次電池電極を提供することを目的とする。 INDUSTRIAL APPLICABILITY The present invention is a non-aqueous secondary battery electrode binder that can effectively improve the peeling strength of the electrode active material layer with respect to the current collector in a non-aqueous secondary battery, and contribute to the reduction of the internal resistance of the battery and the improvement of the cycle characteristics. It is an object of the present invention to provide a non-aqueous secondary battery electrode binder composition and a non-aqueous secondary battery electrode.
　上記課題を解決するため、本発明は以下の［１］～［１４］の通りである。
［１］　共重合体（Ａ）及び共重合体（Ｂ）を含む非水系二次電池電極バインダーであって、
　前記共重合体（Ａ）は、エチレン性不飽和結合を有する化合物の重合体であり、
　前記共重合体（Ａ）は、単量体（ａ１）に由来する第１１構造単位と、単量体（ａ２）に由来する第１２構造単位と、を有し；或いは、単量体（ａ１）に由来する第１１構造単位と、単量体（ａ２）に由来する第１２構造単位と、内部架橋剤（ａ３）に由来する第１３構造単位と、を有し、
　前記単量体（ａ１）は、エチレン性不飽和結合を有し、ヒドロキシ基及びシアノ基のいずれも有さず、独立した複数のエチレン性不飽和結合を有しないノニオン性化合物であり、
　前記単量体（ａ２）は、エチレン性不飽和結合及びアニオン性官能基を有し、独立した複数のエチレン性不飽和結合を有しない化合物であり、
　前記内部架橋剤（ａ３）は、独立した複数のエチレン性不飽和結合を有し、前記単量体（ａ１）及び前記単量体（ａ２）を含む単量体のラジカル重合において架橋構造を形成可能な化合物であり、
　前記共重合体（Ａ）において、前記第１１構造単位１００質量部に対する、前記第１２構造単位の含有量は１．０質量部以上３０質量部以下であり、
　前記共重合体（Ａ）において、前記第１１構造単位１００質量部に対する、前記第１３構造単位の含有量は、０質量部以上２０質量部以下であり、
　前記共重合体（Ｂ）は、下記式（１）で表される第２１構造単位を全構造単位中５．０モル％以上９８モル％以下、下記式（２）で表される第２２構造単位を全構造単位中０．３０モル％以上９０モル％以下、及び下記式（３）で表される第２３構造単位を全構造単位中０．３０モル％以上１０モル％以下有し、
　前記共重合体（Ｂ）における、全構造単位中の、前記第２１構造単位、前記第２２構造単位、及び前記第２３構造単位の合計含有率は、９０質量％以上であり、
　前記共重合体（Ａ）の含有量と、前記共重合体（Ｂ）の含有量との質量比は、５０．０／５０．０以上９９．０／１．０以下であることを特徴とする非水系二次電池電極バインダー。
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000006
 　（式（２）において、Ｒ１は、分岐を有してもよい炭素数１以上６以下のアルキル基である。）
Figure JPOXMLDOC01-appb-C000007
 　（式（３）において、Ｒ２は、エチレン性不飽和結合を有する基である。）
［２］　前記共重合体（Ｂ）は、
　　前記第２１構造単位を、５．０モル％以上５０モル％以下、
　　前記第２２構造単位を、４０モル％以上９０モル％以下、
　　前記第２３構造単位を、０．３０モル％以上１０モル％以下
含む［１］に記載の非水系二次電池電極バインダー。
［３］　前記共重合体（Ｂ）は、
　　前記第２１構造単位を、７０モル％以上９８モル％以下、
　　前記第２２構造単位を、０．３０モル％以上２０モル％以下、
　　前記第２３構造単位を、０．３０モル％以上１０モル％以下
含む［１］に記載の非水系二次電池電極バインダー。
［４］　前記式（３）において、Ｒ２は、ビニルオキシ基、アリルオキシ基、（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、及び－ＯＣＨ２－ＣＨ２－ＣＨ２＝ＣＨ２からなる群より選ばれる少なくともいずれか１つを有する［１］～［３］のいずれかに記載の非水系二次電池電極バインダー。
［５］　前記式（３）において、Ｒ２は、下記式（４）で表される［１］～［４］のいずれかに記載の非水系二次電池電極バインダー。
Figure JPOXMLDOC01-appb-C000008
 （式（４）において、Ｒ２１は分岐を有してもよい炭素数１～５のアルキレン基であり、Ｒ２２は、ビニルオキシ基、アリルオキシ基、（メタ）アクリロイル基、及び（メタ）アクリロイルオキシ基からなる群より選ばれる１つの官能基である。）
［６］　前記共重合体（Ｂ）は、第２１構造単位からなる第１ブロック、第２２構造単位からなる第２ブロック、及び第２３構造単位からなる第３ブロックを有するブロック共重合体である［１］～［５］のいずれかに記載の非水系二次電池電極バインダー。
［７］　前記単量体（ａ１）は、極性官能基を有さない［１］～［６］のいずれかに記載の非水系二次電池電極バインダー。
［８］　前記単量体（ａ２）は、カルボキシ基、及びスルホ基のうち少なくともいずれかを有する化合物である［１］～［７］のいずれかに記載の非水系二次電池電極バインダー。
［９］　前記共重合体（Ａ）は、前記第１１構造単位及び前記第１２構造単位を合計で８０質量％以上含む［１］～［８］のいずれかに記載の非水系二次電池電極バインダー。［１０］　前記共重合体（Ａ）において、前記第１１構造単位１００質量部に対する、前記第１３構造単位の含有量は、０．０５０質量部以上である［１］～［９］のいずれかに記載の非水系二次電池電極バインダー。
［１１］　［１］～［１０］のいずれかに記載の非水系二次電池電極バインダーと水性媒体とを含む非水系二次電池電極バインダー組成物。
［１２］　［１］～［１０］のいずれかに記載の非水系二次電池電極バインダーと、電極活物質と、水性媒体と、を含み、
　該水性媒体は、水、親水性の溶媒、及び水と親水性の溶媒とを含む混合物からなる群から選択される１つ媒体である非水系二次電池電極スラリー。
［１３］　［１］～［１０］のいずれかに記載の非水系二次電池電極バインダーを含む非水系二次電池電極。
［１４］　［１３］に記載の非水系二次電池電極を含む、非水系二次電池。 In order to solve the above problems, the present invention is as follows [1] to [14].
[1] A non-aqueous secondary battery electrode binder containing the copolymer (A) and the copolymer (B).
The copolymer (A) is a polymer of a compound having an ethylenically unsaturated bond.
The copolymer (A) has an eleventh structural unit derived from the monomer (a1) and a twelfth structural unit derived from the monomer (a2); or the monomer (a1). ), A twelfth structural unit derived from the monomer (a2), and a thirteenth structural unit derived from the internal cross-linking agent (a3).
The monomer (a1) is a nonionic compound having an ethylenically unsaturated bond, having neither a hydroxy group nor a cyano group, and having a plurality of independent ethylenically unsaturated bonds.
The monomer (a2) is a compound having an ethylenically unsaturated bond and an anionic functional group and not having a plurality of independent ethylenically unsaturated bonds.
The internal cross-linking agent (a3) has a plurality of independent ethylenically unsaturated bonds and forms a cross-linked structure by radical polymerization of the monomer (a1) and the monomer containing the monomer (a2). It is a possible compound and
In the copolymer (A), the content of the 12th structural unit with respect to 100 parts by mass of the 11th structural unit is 1.0 part by mass or more and 30 parts by mass or less.
In the copolymer (A), the content of the 13th structural unit with respect to 100 parts by mass of the 11th structural unit is 0 parts by mass or more and 20 parts by mass or less.
The copolymer (B) contains the 21st structural unit represented by the following formula (1) in an amount of 5.0 mol% or more and 98 mol% or less, and the 22nd structure represented by the following formula (2). The unit has 0.30 mol% or more and 90 mol% or less in all structural units, and the 23rd structural unit represented by the following formula (3) has 0.30 mol% or more and 10 mol% or less in all structural units.
The total content of the 21st structural unit, the 22nd structural unit, and the 23rd structural unit in the total structural unit of the copolymer (B) is 90% by mass or more.
The mass ratio of the content of the copolymer (A) to the content of the copolymer (B) is 50.0 / 50.0 or more and 99.0 / 1.0 or less. Non-aqueous secondary battery electrode binder.
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000006
 (In the formula (2), R 1 is an alkyl group having 1 or more and 6 or less carbon atoms which may have a branch.)
Figure JPOXMLDOC01-appb-C000007
 (In formula (3), R 2 is a group having an ethylenically unsaturated bond.)
[2] The copolymer (B) is
The 21st structural unit is 5.0 mol% or more and 50 mol% or less,
The 22nd structural unit is 40 mol% or more and 90 mol% or less,
The non-aqueous secondary battery electrode binder according to [1], which contains the 23rd structural unit in an amount of 0.30 mol% or more and 10 mol% or less.
[3] The copolymer (B) is
The 21st structural unit is 70 mol% or more and 98 mol% or less,
The 22nd structural unit is 0.30 mol% or more and 20 mol% or less,
The non-aqueous secondary battery electrode binder according to [1], which contains the 23rd structural unit in an amount of 0.30 mol% or more and 10 mol% or less.
[4] In the above formula (3), R 2 is composed of a vinyloxy group, an allyloxy group, a (meth) acryloyl group, a (meth) acryloyloxy group, and -OCH 2 -CH 2 -CH 2 = CH 2 . The non-aqueous secondary battery electrode binder according to any one of [1] to [3], which has at least one selected.
[5] In the formula (3), R 2 is a non-aqueous secondary battery electrode binder according to any one of [1] to [4] represented by the following formula (4).
Figure JPOXMLDOC01-appb-C000008
 (In the formula (4), R 21 is an alkylene group having 1 to 5 carbon atoms which may have a branch, and R 22 is a vinyloxy group, an allyloxy group, a (meth) acryloyl group, and a (meth) acryloyloxy. It is one functional group selected from the group consisting of groups.)
[6] The block copolymer (B) is a block copolymer having a first block composed of a 21st structural unit, a second block composed of a 22nd structural unit, and a third block composed of a 23rd structural unit. The non-aqueous secondary battery electrode binder according to any one of [1] to [5].
[7] The non-aqueous secondary battery electrode binder according to any one of [1] to [6], wherein the monomer (a1) does not have a polar functional group.
[8] The non-aqueous secondary battery electrode binder according to any one of [1] to [7], wherein the monomer (a2) is a compound having at least one of a carboxy group and a sulfo group.
[9] The non-aqueous secondary battery electrode according to any one of [1] to [8], wherein the copolymer (A) contains 80% by mass or more of the 11th structural unit and the 12th structural unit in total. binder. [10] In the copolymer (A), the content of the 13th structural unit with respect to 100 parts by mass of the 11th structural unit is 0.050 parts by mass or more, any of [1] to [9]. The non-aqueous secondary battery electrode binder described in 1.
[11] A non-aqueous secondary battery electrode binder composition comprising the non-aqueous secondary battery electrode binder according to any one of [1] to [10] and an aqueous medium.
[12] The non-aqueous secondary battery electrode binder according to any one of [1] to [10], an electrode active material, and an aqueous medium are included.
The aqueous medium is a non-aqueous secondary battery electrode slurry which is one medium selected from the group consisting of water, a hydrophilic solvent, and a mixture containing water and a hydrophilic solvent.
[13] A non-aqueous secondary battery electrode comprising the non-aqueous secondary battery electrode binder according to any one of [1] to [10].
[14] A non-aqueous secondary battery including the non-aqueous secondary battery electrode according to [13].
　本発明によれば、非水系二次電池において電極活物質層の集電体に対する剥離強度を効果的に向上させ、電池の内部抵抗の低減及びサイクル特性の向上に貢献できる非水系二次電池電極バインダー、非水系二次電池電極バインダー組成物、及び非水系二次電池電極を提供することができる。 According to the present invention, in a non-aqueous secondary battery, the peeling strength of the electrode active material layer with respect to the current collector can be effectively improved, and the non-aqueous secondary battery electrode can contribute to the reduction of the internal resistance of the battery and the improvement of the cycle characteristics. Binders, non-aqueous secondary battery electrode binder compositions, and non-aqueous secondary battery electrodes can be provided.
　以下、本発明の実施形態として、非水系二次電池電極バインダー（非水系二次電池電極用バインダーともいう）、非水系二次電池電極バインダー組成物（非水系二次電池電極用バインダー組成物ともいう）、非水系二次電池電極スラリー（非水系二次電池電極用スラリーともいう）、非水系二次電池電極、及び非水系二次電池について説明する。 Hereinafter, as an embodiment of the present invention, both a non-aqueous secondary battery electrode binder (also referred to as a non-aqueous secondary battery electrode binder) and a non-aqueous secondary battery electrode binder composition (also referred to as a non-aqueous secondary battery electrode binder composition). A non-aqueous secondary battery electrode slurry (also referred to as a non-aqueous secondary battery electrode slurry), a non-aqueous secondary battery electrode, and a non-aqueous secondary battery will be described.
　「（メタ）アクリル」とは、アクリル及びメタクリルの総称であり、「（メタ）アクリレート」とは、アクリレート及びメタクリレートの総称である。 "(Meta) acrylic" is a general term for acrylic and methacrylic, and "(meth) acrylate" is a general term for acrylate and methacrylate.
　「不揮発分」は、直径５ｃｍのアルミ皿に組成物を１ｇ秤量し、１気圧（１０１３ｈＰａ）で、乾燥器内で空気を循環させながら１０５℃で１時間乾燥させ後に残った成分である。組成物の形態は、溶液、分散液、スラリーが挙げられるが、これらに限られない。「不揮発分濃度」とは、乾燥前の組成物の質量（１ｇ）に対する、上記条件下で乾燥後の不揮発分の質量割合（質量％）である。 The "nonvolatile component" is a component remaining after weighing 1 g of the composition in an aluminum dish having a diameter of 5 cm and drying at 105 ° C. for 1 hour while circulating air in a dryer at 1 atm (1013 hPa). The form of the composition includes, but is not limited to, a solution, a dispersion, and a slurry. The "nonvolatile content concentration" is the mass ratio (mass%) of the non-volatile content after drying under the above conditions with respect to the mass (1 g) of the composition before drying.
　「エチレン性不飽和結合」とは、特に断りがない限り、ラジカル重合性を有するエチレン性不飽和結合を指す。 "Ethylene unsaturated bond" refers to an ethylenically unsaturated bond having radical polymerization unless otherwise specified.
　エチレン性不飽和結合を有する化合物の重合体において、あるエチレン性不飽和結合を有する化合物に由来する構造単位は、その化合物のエチレン性不飽和結合以外の部分の化学構造と、重合体におけるその構造単位のエチレン性不飽和結合に対応する部分以外の部分の化学構造とが同じであるとする。例えば、アクリル酸由来の構造単位は、重合体において－ＣＨ２ＣＨ（ＣＯＯＨ）－の構造を有している。 In the polymer of a compound having an ethylenically unsaturated bond, the structural unit derived from the compound having a certain ethylenically unsaturated bond is the chemical structure of the portion other than the ethylenically unsaturated bond of the compound and its structure in the polymer. It is assumed that the chemical structure of the part other than the part corresponding to the ethylenically unsaturated bond of the unit is the same. For example, the structural unit derived from acrylic acid has a structure of −CH 2 CH (COOH) − in the polymer.
　また、独立した複数のエチレン性不飽和結合を有する化合物については、重合体の構造単位としてエチレン性不飽和結合が残っていてもよい。独立した複数のエチレン性不飽和結合とは、互いに共役ジエンを形成しない複数のエチレン性不飽和結合を言う。例えば、ジビニルベンゼン由来の構造単位は、エチレン性不飽和結合を有さない構造（いずれのエチレン性不飽和結合に対応する部分も重合体の鎖に取り込まれた形態）でもよく、１個のエチレン性不飽和結合を有する構造（一方のエチレン性不飽和結合に対応する部分のみ重合体の鎖に取り込まれた形態）でもよい。 Further, for a compound having a plurality of independent ethylenically unsaturated bonds, an ethylenically unsaturated bond may remain as a structural unit of the polymer. A plurality of independent ethylenically unsaturated bonds are a plurality of ethylenically unsaturated bonds that do not form conjugated diene with each other. For example, the structural unit derived from divinylbenzene may have a structure having no ethylenically unsaturated bond (a form in which a portion corresponding to any ethylenically unsaturated bond is incorporated into a polymer chain), or one ethylene. A structure having a sex-unsaturated bond (a form in which only the portion corresponding to one ethylenically unsaturated bond is incorporated into the polymer chain) may be used.
　さらに、重合後にエチレン性不飽和結合に対応する鎖以外の部分を化学反応させる等、単量体の化学構造と重合体の化学構造とで対応しない場合は、重合後の化学構造を基準とする。例えば、酢酸ビニルを重合し、その後けん化した場合においては、重合体の化学構造を基準に考えて、酢酸ビニル由来の構造単位ではなく、ビニルアルコール由来の構造単位とする。 Furthermore, if the chemical structure of the monomer does not correspond to the chemical structure of the polymer, such as chemical reaction of the part other than the chain corresponding to the ethylenically unsaturated bond after polymerization, the chemical structure after polymerization is used as a reference. .. For example, when vinyl acetate is polymerized and then saponified, it is not a structural unit derived from vinyl acetate but a structural unit derived from vinyl alcohol in consideration of the chemical structure of the polymer.
＜１．非水系二次電池電極バインダー＞
　本発明にかかる非水系二次電池電極バインダーは共重合体（Ａ）及び共重合体（Ｂ）を含む。以下、特に断りがなければ、電極バインダーは、本発明にかかる非水系二次電池電極バインダーを意味する。電極バインダーは、その他の成分を含んでもよく、例えば、共重合体（Ａ）及び共重合体（Ｂ）以外の重合体を含んでもよい。本発明にかかる非水系二次電池電極バインダーは共重合体（Ａ）及び共重合体（Ｂ）からなることが好ましい。
以下、共重合体（Ａ）及び共重合体（Ｂ）について詳細に述べる。 <1. Non-aqueous secondary battery electrode binder ＞
The non-aqueous secondary battery electrode binder according to the present invention contains the copolymer (A) and the copolymer (B). Hereinafter, unless otherwise specified, the electrode binder means a non-aqueous secondary battery electrode binder according to the present invention. The electrode binder may contain other components, and may contain, for example, a polymer other than the copolymer (A) and the copolymer (B). The non-aqueous secondary battery electrode binder according to the present invention is preferably made of the copolymer (A) and the copolymer (B).
Hereinafter, the copolymer (A) and the copolymer (B) will be described in detail.
〔１－１．共重合体（Ａ）〕
　共重合体（Ａ）は、エチレン性不飽和結合を有する化合物の重合体である。共重合体（Ａ）は、単量体（ａ１）に由来する第１１構造単位と、単量体（ａ２）に由来する第１２構造単位と、を有する。共重合体（Ａ）は、さらに内部架橋剤（ａ３）に由来する第１３構造単位を有してもよい。共重合体（Ａ）は、単量体（ａ１）、単量体（ａ２）、及び内部架橋剤（ａ３）のいずれにも該当しないその他の単量体（ａ４）に由来する構造単位を含んでもよい。それぞれの単量体及び内部架橋剤の詳細については以下に説明する。 [1-1. Copolymer (A)]
The copolymer (A) is a polymer of a compound having an ethylenically unsaturated bond. The copolymer (A) has an eleventh structural unit derived from the monomer (a1) and a twelfth structural unit derived from the monomer (a2). The copolymer (A) may further have a thirteenth structural unit derived from the internal cross-linking agent (a3). The copolymer (A) contains a structural unit derived from another monomer (a4) that does not fall under any of the monomer (a1), the monomer (a2), and the internal cross-linking agent (a3). But it may be. Details of each monomer and internal cross-linking agent will be described below.
［１－１－１．単量体（ａ１）］
　単量体（ａ１）は、エチレン性不飽和結合を有し、独立した複数のエチレン性不飽和結合を有しないノニオン性（アニオン性官能基及びカチオン性官能基のいずれも有さない）化合物である。単量体（ａ１）は、ポリオキシアルキレン構造を有さないことが好ましい。 [1-1-1. Monomer (a1)]
The monomer (a1) is a nonionic (neither anionic or cationic functional group) compound having an ethylenically unsaturated bond and not having a plurality of independent ethylenically unsaturated bonds. be. The monomer (a1) preferably does not have a polyoxyalkylene structure.
　単量体（ａ１）は、ヒドロキシ基及びシアノ基のいずれも有さない。単量体（ａ１）は、極性官能基を有さないことが好ましい。単量体（ａ１）は、１種類の化合物のみを含んでもよく、２種類以上の化合物を含んでもよい。単量体（ａ１）は、極性官能基を有しない（メタ）アクリル酸エステル及び芳香族ビニル化合物のうち少なくともいずれかであることが好ましく、両方を含むことがより好ましい。極性官能基を有しない（メタ）アクリル酸エステルは、（メタ）アクリル酸アルキルエステルを含むことがさらに好ましい。単量体（ａ１）における、（メタ）アクリル酸アルキルエステル及び芳香族ビニル化合物の合計含有率は８０質量％以上であることがさらに好ましく、９０質量％以上であることがさらに好ましく、１００質量％であることが最も好ましい。 The monomer (a1) has neither a hydroxy group nor a cyano group. The monomer (a1) preferably has no polar functional group. The monomer (a1) may contain only one kind of compound, or may contain two or more kinds of compounds. The monomer (a1) is preferably at least one of a (meth) acrylic acid ester having no polar functional group and an aromatic vinyl compound, and more preferably containing both. The (meth) acrylic acid ester having no polar functional group more preferably contains a (meth) acrylic acid alkyl ester. The total content of the (meth) acrylic acid alkyl ester and the aromatic vinyl compound in the monomer (a1) is more preferably 80% by mass or more, further preferably 90% by mass or more, and 100% by mass. Is most preferable.
　また、単量体（ａ１）の組成について、共重合体（Ａ）のガラス転移点を調整するため、あるいは分子設計に応じた重合速度を調整するために、本発明で規定する範囲内で、好ましい化合物及びその量を適宜調整することが好ましい。 Further, regarding the composition of the monomer (a1), in order to adjust the glass transition point of the copolymer (A) or to adjust the polymerization rate according to the molecular design, within the range specified in the present invention. It is preferable to appropriately adjust the preferred compound and the amount thereof.
　（メタ）アクリル酸アルキルエステルとしては、例えば、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ｎ－プロピル、（メタ）アクリル酸イソプロピル、（メタ）アクリル酸ｎ－ブチル、（メタ）アクリル酸ｔｅｒｔ－ブチル、（メタ）アクリル酸シクロヘキシル、（メタ）アクリル酸２－エチルヘキシル、（メタ）アクリル酸イソボルニル、（メタ）アクリル酸ラウリル、（メタ）アクリル酸ステアリル等が挙げられる。 Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, n-propyl (meth) acrylic acid, isopropyl (meth) acrylic acid, and n-butyl (meth) acrylic acid. , (Meta) tert-butyl acrylate, (meth) cyclohexyl acrylate, (meth) 2-ethylhexyl acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and the like. ..
　ここで芳香族ビニル化合物は、（メタ）アクリロイル基を含まない。芳香族ビニル化合物としては、例えば、スチレン、ｔ－ブチルスチレン、α－メチルスチレン、ｐ－メチルスチレン、１，１－ジフェニルエチレン等が挙げられる。単量体（ａ１）が芳香族ビニル化合物を含む場合、単量体（ａ１）は、スチレン、α－メチルスチレンの少なくともいずれかを含むことがより好ましく、スチレンを含むことがさらに好ましい。 Here, the aromatic vinyl compound does not contain a (meth) acryloyl group. Examples of the aromatic vinyl compound include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, 1,1-diphenylethylene and the like. When the monomer (a1) contains an aromatic vinyl compound, the monomer (a1) more preferably contains at least one of styrene and α-methylstyrene, and further preferably contains styrene.
　単量体（ａ１）は、互いに共役ジエンを形成する複数のエチレン性不飽和結合を含んでもよい。互いに共役ジエンを形成する複数のエチレン性不飽和結合を有する化合物としては、例えば、１，３－ブタジエン、１，３－ペンタジエン等が挙げられる。 The monomer (a1) may contain a plurality of ethylenically unsaturated bonds forming conjugated diene with each other. Examples of the compound having a plurality of ethylenically unsaturated bonds forming conjugated diene with each other include 1,3-butadiene, 1,3-pentadiene and the like.
［１－１－２．単量体（ａ２）］
　単量体（ａ２）は、エチレン性不飽和結合及びアニオン性官能基を有する化合物である。単量体（ａ２）は、独立した複数のエチレン性不飽和結合を有しない。単量体（ａ２）は、ポリオキシアルキレン構造を有さないことが好ましい。アニオン性官能基としては、例えば、カルボキシ基、スルホ基、及びリン酸基等が挙げられる。また、アニオン性官能基は、塩を形成していてもよい。単量体（ａ２）は、カルボキシ基、及びスルホ基のうち少なくともいずれかを有する化合物を含むことが好ましく、カルボキシ基を有する化合物を含むことがより好ましい。 [1-1-2. Monomer (a2)]
The monomer (a2) is a compound having an ethylenically unsaturated bond and an anionic functional group. The monomer (a2) does not have multiple independent ethylenically unsaturated bonds. The monomer (a2) preferably does not have a polyoxyalkylene structure. Examples of the anionic functional group include a carboxy group, a sulfo group, a phosphoric acid group and the like. Further, the anionic functional group may form a salt. The monomer (a2) preferably contains a compound having at least one of a carboxy group and a sulfo group, and more preferably contains a compound having a carboxy group.
　単量体（ａ２）は、１種類の化合物のみを含んでもよく、２種類以上の化合物を含んでもよい。単量体（ａ２）は、１分子中に、同種のアニオン性官能基を複数有する化合物を含んでもよい。すなわち、共重合体（Ａ）は、１つの構造単位中に同種のアニオン性官能基を複数含んでもよい。単量体（ａ２）は、１分子中に、２種類以上の異なるアニオン性官能基を有する化合物を含んでもよい。すなわち、共重合体（Ａ）は、１つの構造単位中に２種類以上の異なるアニオン性官能基を含んでもよい。また、単量体（ａ２）は、異なるアニオン性官能基を含む２種類以上の化合物を含んでいてもよい。すなわち、共重合体（Ａ）は、異なるアニオン性官能基を含む２種類以上の構造単位を含んでもよい。 The monomer (a2) may contain only one kind of compound, or may contain two or more kinds of compounds. The monomer (a2) may contain a compound having a plurality of the same kind of anionic functional groups in one molecule. That is, the copolymer (A) may contain a plurality of anionic functional groups of the same type in one structural unit. The monomer (a2) may contain a compound having two or more different anionic functional groups in one molecule. That is, the copolymer (A) may contain two or more different anionic functional groups in one structural unit. Further, the monomer (a2) may contain two or more kinds of compounds containing different anionic functional groups. That is, the copolymer (A) may contain two or more structural units containing different anionic functional groups.
　単量体（ａ２）としては、（メタ）アクリル酸、クロトン酸等の不飽和モノカルボン酸；マレイン酸、フマル酸、イタコン酸等の不飽和ジカルボン酸；不飽和ジカルボン酸のハーフエステル；パラスチレンスルホン酸等が挙げられる。これらの中でも、単量体（ａ２）は（メタ）アクリル酸、イタコン酸のうち少なくとも１つを含むことが好ましい。 Examples of the monomer (a2) include unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid; half esters of unsaturated dicarboxylic acids; parastyrene. Examples include sulfonic acid. Among these, the monomer (a2) preferably contains at least one of (meth) acrylic acid and itaconic acid.
　単量体（ａ２）に由来する構造単位の少なくとも一部は、塩基性物質との塩を形成していてもよい。ここで、塩を形成している単量体（ａ２）としては、（メタ）アクリル酸ナトリウム、パラスチレンスルホン酸ナトリウム等が挙げられる。 At least a part of the structural unit derived from the monomer (a2) may form a salt with a basic substance. Here, examples of the monomer (a2) forming the salt include sodium (meth) acrylate, sodium parastyrene sulfonate, and the like.
　単量体（ａ２）は、エチレン性不飽和結合を有するスルホン酸及びその塩のうち少なくともいずれかを含むことが好ましく、エチレン性不飽和結合を有するスルホン酸塩を含むことがより好ましい。スルホン酸としては、スルホ基を有する芳香族ビニル化合物を含むことが好ましく、パラスチレンスルホン酸を含むことがより好ましい。スルホン酸塩としては、スルホ基を有する芳香族ビニル化合物の塩を含むことが好ましく、パラスチレンスルホン酸塩を含むことがより好ましく、パラスチレンスルホン酸ナトリウムを含むことがさらに好ましい。後述する電極バインダー組成物において粗粒の発生を抑制できるためである。 The monomer (a2) preferably contains at least one of a sulfonic acid having an ethylenically unsaturated bond and a salt thereof, and more preferably contains a sulfonic acid salt having an ethylenically unsaturated bond. The sulfonic acid preferably contains an aromatic vinyl compound having a sulfo group, and more preferably contains parastyrene sulfonic acid. The sulfonate preferably contains a salt of an aromatic vinyl compound having a sulfo group, more preferably contains a parastyrene sulfonate, and even more preferably contains sodium parastyrene sulfonate. This is because the generation of coarse particles can be suppressed in the electrode binder composition described later.
［１－１－３．内部架橋剤（ａ３）］
　内部架橋剤（ａ３）は、独立した複数のエチレン性不飽和結合を有し、単量体（ａ１）及び（ａ２）を含む単量体のラジカル重合において架橋構造を形成可能な化合物である。このような化合物としては、ジビニルベンゼン、エチレングリコールジ（メタ）アクリレート、１，６－ヘキサンジオールジ（メタ）アクリレート、２－ヒドロキシ－３－アクリロイロキシプロピルメタクリレート等が挙げられる。 [1-1-3. Internal cross-linking agent (a3)]
The internal cross-linking agent (a3) is a compound having a plurality of independent ethylenically unsaturated bonds and capable of forming a cross-linked structure by radical polymerization of a monomer containing the monomers (a1) and (a2). Examples of such a compound include divinylbenzene, ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate and the like.
［１－１－４．その他の単量体（ａ４）］
　その他の単量体（ａ４）は、単量体（ａ１）～（ａ３）のいずれにも該当しない。その他の単量体（ａ４）としては、エチレン性不飽和結合及び極性官能基を有する化合物、エチレン性不飽和結合を有する界面活性剤（以下、「重合性界面活性剤」とすることもある）、エチレン性不飽和結合を有しシランカップリング剤としての機能を有する化合物等が挙げられるがこれらに限られない。 [1-1-4. Other monomers (a4)]
The other monomer (a4) does not correspond to any of the monomers (a1) to (a3). Examples of the other monomer (a4) include a compound having an ethylenically unsaturated bond and a polar functional group, and a surfactant having an ethylenically unsaturated bond (hereinafter, may be referred to as "polymerizable surfactant"). , Compounds having an ethylenically unsaturated bond and having a function as a silane coupling agent, and the like are not limited thereto.
　極性官能基としては、ヒドロキシ基及びシアノ基のうち少なくともいずれかを含むことが好ましい。エチレン性不飽和結合及び極性官能基を有する単量体としては、例えば、（メタ）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）アクリロニトリル等が挙げられる。共重合体（Ａ）は、エチレン性不飽和結合及びヒドロキシ基を含む化合物に由来する構造単位を含むことが好ましく、ヒドロキシ基を有する（メタ）アクリレートに由来する構造単位を有することがより好ましく、（メタ）アクリル酸２－ヒドロキシエチルに由来する構造単位を含むことがさらに好ましい。 The polar functional group preferably contains at least one of a hydroxy group and a cyano group. Examples of the monomer having an ethylenically unsaturated bond and a polar functional group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl acrylate, and (meth) acrylonitrile. The copolymer (A) preferably contains a structural unit derived from an ethylenically unsaturated bond and a compound containing a hydroxy group, and more preferably has a structural unit derived from a (meth) acrylate having a hydroxy group. It is more preferable to contain a structural unit derived from 2-hydroxyethyl (meth) acrylate.
　重合性界面活性剤としては、エチレン性不飽和結合を有し、かつ界面活性剤としての機能を有する化合物で、例えば、以下の化学式（６）～（９）で表される化合物等が挙げられる。 Examples of the polymerizable surfactant include compounds having an ethylenically unsaturated bond and having a function as a surfactant, and examples thereof include compounds represented by the following chemical formulas (6) to (9). ..
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000009
　式（６）中、Ｒ３はアルキル基であることが好ましく、ｐは１０～４０の整数であることが好ましい。Ｒ３の炭素数は１０～４０であることがより好ましく、Ｒ３は炭素数１０～４０の直鎖無置換アルキル基であることがさらに好ましい。 In formula (6), R 3 is preferably an alkyl group, and p is preferably an integer of 10 to 40. It is more preferable that R 3 has 10 to 40 carbon atoms, and it is further preferable that R 3 is a linear unsubstituted alkyl group having 10 to 40 carbon atoms.
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000010
　式（７）中、Ｒ４はアルキル基であることが好ましく、ｑは１０～１２の整数であることが好ましい。Ｒ４の炭素数は１０～４０であることがより好ましく、Ｒ４は炭素数１０～４０の直鎖無置換アルキル基であることがさらに好ましい。 In formula (7), R 4 is preferably an alkyl group, and q is preferably an integer of 10 to 12. It is more preferable that R 4 has 10 to 40 carbon atoms, and it is further preferable that R 4 is a linear unsubstituted alkyl group having 10 to 40 carbon atoms.
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000011
　式（８）中、Ｒ５はアルキル基であることが好ましく、Ｍ１はＮＨ４またはＮａであることが好ましい。Ｒ５の炭素数は１０～４０であることがより好ましく、Ｒ５は炭素数１０～４０の直鎖無置換アルキル基であることがさらに好ましい。 In formula (8), R 5 is preferably an alkyl group, and M 1 is preferably NH 4 or Na. It is more preferable that R 5 has 10 to 40 carbon atoms, and it is further preferable that R 5 is a linear unsubstituted alkyl group having 10 to 40 carbon atoms.
Figure JPOXMLDOC01-appb-C000012
Figure JPOXMLDOC01-appb-C000012
　式（９）中、Ｒ６はアルキル基であることが好ましく、Ｍ２はＮＨ４またはＮａであることが好ましい。Ｒ６の炭素数は１０～４０であることがより好ましく、Ｒ６は炭素数１０～４０の直鎖無置換アルキル基であることがさらに好ましい。 In formula (9), R 6 is preferably an alkyl group, and M 2 is preferably NH 4 or Na. It is more preferable that R 6 has 10 to 40 carbon atoms, and it is further preferable that R 6 is a linear unsubstituted alkyl group having 10 to 40 carbon atoms.
　エチレン性不飽和結合を有しシランカップリング剤としての機能を有する化合物としては、例えば、ビニルトリメトキシシラン、γ－メタクリロキシプロピルトリメトキシシラン、ビニルトリエトキシシラン、γ－メタクリロキシプロピルトリエトキシシラン等が挙げられる。 Examples of the compound having an ethylenically unsaturated bond and having a function as a silane coupling agent include vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltriethoxysilane. And so on.
〔１－１－５．共重合体（Ａ）における各構造単位の含有量〕
　共重合体（Ａ）において、単量体（ａ１）に由来する第１１構造単位１００質量部に対する、単量体（ａ２）に由来する第１２構造単位の含有量は、１．０質量部以上であり、２．０質量部以上であることが好ましく、３．５質量部以上であることがより好ましい。電極バインダーの機械的安定性が向上するためである。また、本発明にかかる電極バインダーを含む電極活物質層の剥離強度が向上するためである。 [1-1-5. Content of each structural unit in the copolymer (A)]
In the copolymer (A), the content of the 12th structural unit derived from the monomer (a2) is 1.0 part by mass or more with respect to 100 parts by mass of the 11th structural unit derived from the monomer (a1). It is preferably 2.0 parts by mass or more, and more preferably 3.5 parts by mass or more. This is because the mechanical stability of the electrode binder is improved. This is also because the peel strength of the electrode active material layer containing the electrode binder according to the present invention is improved.
　共重合体（Ａ）において、単量体（ａ１）に由来する第１１構造単位１００質量部に対する、単量体（ａ２）に由来する第１２構造単位の含有量は、３０質量部以下であり、１５質量部以下であることが好ましく、７．５質量部以下であることがより好ましい。電極バインダーのゲル化を抑制するためである。また、電極バインダーの機械的安定性が向上するためである。 In the copolymer (A), the content of the 12th structural unit derived from the monomer (a2) is 30 parts by mass or less with respect to 100 parts by mass of the 11th structural unit derived from the monomer (a1). , 15 parts by mass or less, more preferably 7.5 parts by mass or less. This is to suppress gelation of the electrode binder. This is also because the mechanical stability of the electrode binder is improved.
　第１１構造単位及び第１２構造単位の共重合体（Ａ）に占める質量割合は、合計で８０質量％以上であることが好ましく、８５質量％以上であることがより好ましく、９０質量％以上であることがさらに好ましい。これらの構造単位の含有率を高めることで、本発明により得られる効果がより一層大きくなるためである。 The mass ratio of the 11th structural unit and the 12th structural unit to the copolymer (A) is preferably 80% by mass or more, more preferably 85% by mass or more, and 90% by mass or more in total. It is more preferable to have. This is because the effect obtained by the present invention is further enhanced by increasing the content of these structural units.
　共重合体（Ａ）において、内部架橋剤（ａ３）に由来する第１３構造単位を含む場合、単量体（ａ１）に由来する第１１構造単位１００質量部に対する、内部架橋剤（ａ３）に由来する第１３構造単位の含有量は、０質量部以上であり、０．０５０質量部以上であることが好ましく、０．０７５質量部以上であることがより好ましく、０．５０質量部以上であることがさらに好ましい。電極バインダーの劣化を抑制し、本発明にかかる電極バインダーを含む電極活物質層を有する電極を用いた電池のサイクル特性（放電容量維持率）を向上させることができるためである。 When the copolymer (A) contains the thirteenth structural unit derived from the internal cross-linking agent (a3), the internal cross-linking agent (a3) has a portion of 100 parts by mass of the eleventh structural unit derived from the monomer (a1). The content of the derived 13th structural unit is 0 parts by mass or more, preferably 0.050 parts by mass or more, more preferably 0.075 parts by mass or more, and 0.50 parts by mass or more. It is more preferable to have. This is because the deterioration of the electrode binder can be suppressed, and the cycle characteristics (discharge capacity retention rate) of the battery using the electrode having the electrode active material layer containing the electrode binder according to the present invention can be improved.
　共重合体（Ａ）において、内部架橋剤（ａ３）に由来する構造単位を含む場合、単量体（ａ１）に由来する第１１構造単位１００質量部に対する、内部架橋剤（ａ３）に由来する第１３構造単位の含有量は、２０質量部以下であり、７．５質量部以下であることが好ましく、２．５質量部以下であることがより好ましい。電極バインダーのゲル化を抑制するためである。 When the copolymer (A) contains a structural unit derived from the internal cross-linking agent (a3), it is derived from the internal cross-linking agent (a3) with respect to 100 parts by mass of the 11th structural unit derived from the monomer (a1). The content of the thirteenth structural unit is 20 parts by mass or less, preferably 7.5 parts by mass or less, and more preferably 2.5 parts by mass or less. This is to suppress gelation of the electrode binder.
［１－１－６．共重合体（Ａ）のガラス転移点］
　共重合体（Ａ）のガラス転移点Ｔｇは、日立ハイテクサイエンス社製　ＥＸＳＴＡＲ　ＤＳＣ／ＳＳ７０２０を用いて昇温速度１０℃／分、窒素ガス雰囲気下でＤＳＣ測定を行い、ＤＳＣの温度微分として得られるＤＤＳＣチャートのピークトップ温度である。 [1-1-6. Glass transition point of copolymer (A)]
The glass transition point Tg of the copolymer (A) is obtained as a temperature differential of DSC by performing DSC measurement in a nitrogen gas atmosphere at a heating rate of 10 ° C./min using EXSTAR DSC / SS7020 manufactured by Hitachi High-Tech Science. The peak top temperature of the DDSC chart.
　共重合体（Ａ）のガラス転移点Ｔｇは、－３０℃以上であることが好ましく、－１０℃以上であることがより好ましく、０℃以上であることがさらに好ましい。本発明にかかる電極バインダーを含む非水系二次電池のサイクル特性が向上するためである。 The glass transition point Tg of the copolymer (A) is preferably −30 ° C. or higher, more preferably −10 ° C. or higher, and even more preferably 0 ° C. or higher. This is because the cycle characteristics of the non-aqueous secondary battery including the electrode binder according to the present invention are improved.
　共重合体（Ａ）のガラス転移点Ｔｇは、１００℃以下であることが好ましく、５０℃以下であることがより好ましく、３０℃以下であることがさらに好ましい。本発明にかかる電極バインダーを含む電極活物質層の集電箔に対する密着性が向上するためである。 The glass transition point Tg of the copolymer (A) is preferably 100 ° C. or lower, more preferably 50 ° C. or lower, and even more preferably 30 ° C. or lower. This is because the adhesion of the electrode active material layer containing the electrode binder according to the present invention to the current collector foil is improved.
［１－１－７．共重合体（Ａ）の合成方法］
　共重合体（Ａ）は、単量体（ａ１）及び（ａ２）を含む単量体を共重合することで得られる。単量体として、必要に応じて内部架橋剤（ａ３）、他の単量体（ａ４）も共重合してよい。ここで、共重合体（Ａ）を合成するために用いられる単量体を総称して単量体（ａ）と呼ぶこともある。重合方法としては、例えば、水性媒体（ｂ）中での単量体（ａ）の乳化重合が挙げられる。乳化重合による共重合体（Ａ）の合成において用いられるその他の成分としては、例えば、重合性を有さない界面活性剤（ｃ）、塩基性物質（ｄ）、ラジカル重合開始剤（ｅ）、連鎖移動剤（ｆ）等が挙げられる。以下、共重合体（Ａ）の合成のために必要な、あるいは必要に応じて用いてもよいこれらの成分、及び乳化重合法について説明するが、単量体（ａ）については、上述した通りのため、以下においては説明しない。 [1-1-7. Method for synthesizing copolymer (A)]
The copolymer (A) can be obtained by copolymerizing a monomer containing the monomers (a1) and (a2). As the monomer, an internal cross-linking agent (a3) and another monomer (a4) may be copolymerized, if necessary. Here, the monomers used for synthesizing the copolymer (A) may be collectively referred to as the monomer (a). Examples of the polymerization method include emulsion polymerization of the monomer (a) in the aqueous medium (b). Other components used in the synthesis of the copolymer (A) by emulsion polymerization include, for example, a non-polymerizable surfactant (c), a basic substance (d), a radical polymerization initiator (e), and the like. Examples thereof include a chain transfer agent (f). Hereinafter, these components necessary for the synthesis of the copolymer (A) or may be used as needed, and the emulsion polymerization method will be described, but the monomer (a) will be described as described above. Therefore, it will not be described below.
　水性媒体（ｂ）は、水、親水性の溶媒、またはこれらの混合物である。親水性の溶媒としては、メタノール、エタノール、イソプロピルアルコール、及びＮ－メチルピロリドン等が挙げられる。重合安定性の観点から、水性媒体（ｂ）は水であることが好ましい。なお、重合安定性を損なわない限り、水性媒体（ｂ）として、水に親水性の溶媒を添加したものを用いてもよい。 The aqueous medium (b) is water, a hydrophilic solvent, or a mixture thereof. Examples of the hydrophilic solvent include methanol, ethanol, isopropyl alcohol, N-methylpyrrolidone and the like. From the viewpoint of polymerization stability, the aqueous medium (b) is preferably water. As the aqueous medium (b), a water to which a hydrophilic solvent is added may be used as long as the polymerization stability is not impaired.
　単量体（ａ）の乳化重合において、重合性を有さず、かつ後述する共重合体（Ｂ）にも該当しない界面活性剤（ｃ）を用いてもよい。界面活性剤（ｃ）は、重合中及び／または重合後の分散液（エマルジョン）の分散安定性を向上させることができる。界面活性剤（ｃ）としては、アニオン性界面活性剤、ノニオン性界面活性剤を用いることが好ましい。 In the emulsion polymerization of the monomer (a), a surfactant (c) that does not have polymerizability and does not correspond to the copolymer (B) described later may be used. The surfactant (c) can improve the dispersion stability of the dispersion liquid (emulsion) during and / or after the polymerization. As the surfactant (c), it is preferable to use an anionic surfactant or a nonionic surfactant.
　アニオン性界面活性剤としては、例えば、アルキルベンゼンスルホン酸塩、アルキル硫酸エステル塩、ポリオキシエチレンアルキルエーテル硫酸エステル塩、脂肪酸塩が挙げられる。 Examples of the anionic surfactant include an alkylbenzene sulfonate, an alkyl sulfate ester salt, a polyoxyethylene alkyl ether sulfate ester salt, and a fatty acid salt.
　ノニオン性界面活性剤としては、ポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルフェニルエーテル、ポリオキシエチレン多環フェニルエーテル、ポリオキシアルキレンアルキルエーテル、ソルビタン脂肪酸エステル、ポリオキシエチレンソルビタン脂肪酸エステルが挙げられる。 Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polycyclic phenyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, and polyoxyethylene sorbitan fatty acid ester.
　上記の界面活性剤は、１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。 The above-mentioned surfactant may be used alone or in combination of two or more.
　単量体（ａ）を水性媒体（ｂ）中で乳化重合する場合は、塩基性物質（ｄ）を加えてもよい。塩基性物質（ｄ）を加えることで、単量体（ａ）に含まれる酸性成分を中和し、ｐＨを調整することができる。ｐＨを調整することで、乳化重合中及び／または乳化重合後の分散液の機械的安定性、化学的安定性を向上させることができる。 When the monomer (a) is emulsion-polymerized in the aqueous medium (b), the basic substance (d) may be added. By adding the basic substance (d), the acidic component contained in the monomer (a) can be neutralized and the pH can be adjusted. By adjusting the pH, the mechanical stability and chemical stability of the dispersion during and / or after emulsion polymerization can be improved.
　分散液の２３℃でのｐＨは、電極の仕様、後述するスラリー作製の条件等によって適宜調整すればよく、限定はされないが、１．５～１０であることが好ましく、６．０～９．０であることがより好ましく、５．０～９．０であることがさらに好ましい。後述の電極スラリー中の活物質の沈降を抑制するためである。 The pH of the dispersion liquid at 23 ° C. may be appropriately adjusted depending on the specifications of the electrodes, the conditions for preparing the slurry described later, and the like, and is not limited, but is preferably 1.5 to 10, preferably 6.0 to 9. It is more preferably 0, and even more preferably 5.0 to 9.0. This is to suppress the sedimentation of the active material in the electrode slurry described later.
　塩基性物質（ｄ）としては、アンモニア、トリエチルアミン、水酸化ナトリウム、水酸化リチウム等が挙げられる。これらの塩基性物質（ｄ）は、１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。 Examples of the basic substance (d) include ammonia, triethylamine, sodium hydroxide, lithium hydroxide and the like. These basic substances (d) may be used alone or in combination of two or more.
　乳化重合の際に用いられるラジカル重合開始剤（ｅ）としては、特に限定されるものではなく、公知のものを用いることができる。ラジカル重合開始剤としては、例えば、過硫酸アンモニウム、過硫酸カリウムなどの過硫酸塩；過酸化水素；アゾ化合物；ｔ－ブチルハイドロパーオキサイド、ｔｅｒｔ－ブチルパーオキシベンゾエート、クメンハイドロパーオキサイドなどの有機過酸化物が挙げられる。中でも、過硫酸塩及び有機過酸化物が好ましい。本実施形態においては、乳化重合の際にラジカル重合開始剤と、重亜硫酸ナトリウム、ロンガリット、アスコルビン酸等の還元剤とを併用して、レドックス重合してもよい。 The radical polymerization initiator (e) used in the emulsion polymerization is not particularly limited, and known ones can be used. Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate; hydrogen peroxide; azo compounds; organic peroxides such as t-butylhydroperoxide, tert-butylperoxybenzoate and cumenehydroperoxide. Examples include oxides. Of these, persulfates and organic peroxides are preferable. In the present embodiment, a radical polymerization initiator and a reducing agent such as sodium bisulfite, longalit, and ascorbic acid may be used in combination during emulsion polymerization for redox polymerization.
　ラジカル重合開始剤の添加量は、単量体（ａ）１００質量部に対して０．１０質量部以上であることが好ましく、０．８０質量部以上であることがより好ましい。単量体（ａ）の重合時の共重合体（Ａ）への転化率を高くすることができるためである。ラジカル重合開始剤の添加量は、単量体（ａ）１００質量部に対して３．０質量部以下であることが好ましく、２．０質量部以下であることがより好ましい。共重合体（Ａ）の分子量を高くすることができ、電極活物質層の電解液に対する膨潤率を下げることができるためである。 The amount of the radical polymerization initiator added is preferably 0.10 part by mass or more, and more preferably 0.80 part by mass or more with respect to 100 parts by mass of the monomer (a). This is because the conversion rate of the monomer (a) to the copolymer (A) at the time of polymerization can be increased. The amount of the radical polymerization initiator added is preferably 3.0 parts by mass or less, and more preferably 2.0 parts by mass or less with respect to 100 parts by mass of the monomer (a). This is because the molecular weight of the copolymer (A) can be increased and the swelling rate of the electrode active material layer with respect to the electrolytic solution can be reduced.
　連鎖移動剤（ｆ）は、乳化重合において共重合体（Ａ）の分子量を調整するために用いられる。連鎖移動剤（ｆ）としては、ｎ－ドデシルメルカプタン、ｔｅｒｔ－ドデシルメルカプタン、ｎ－ブチルメルカプタン、２－エチルヘキシルチオグリコレート、２－メルカプトエタノール、β－メルカプトプロピオン酸、メチルアルコール、ｎ－プロピルアルコール、イソプロピルアルコール、ｔ－ブチルアルコール、ベンジルアルコール等が挙げられる。 The chain transfer agent (f) is used to adjust the molecular weight of the copolymer (A) in emulsion polymerization. Examples of the chain transfer agent (f) include n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, 2-ethylhexylthioglycolate, 2-mercaptoethanol, β-mercaptopropionic acid, methyl alcohol, and n-propyl alcohol. Examples thereof include isopropyl alcohol, t-butyl alcohol and benzyl alcohol.
　乳化重合法としては、例えば、乳化重合に使用する各成分を連続供給しながら乳化重合する方法等が挙げられる。乳化重合の温度は、特に限定はされないが、例えば、３０～９０℃であり、５０～８５℃であることが好ましく、５５～８０℃であることがさらに好ましい。乳化重合は攪拌しながら行うことが好ましい。また、単量体（ａ）及びラジカル重合開始剤は反応容器内で均一になるよう連続供給することが好ましい。 Examples of the emulsion polymerization method include a method of emulsion polymerization while continuously supplying each component used for emulsion polymerization. The temperature of the emulsion polymerization is not particularly limited, but is, for example, 30 to 90 ° C, preferably 50 to 85 ° C, and even more preferably 55 to 80 ° C. Emulsion polymerization is preferably carried out with stirring. Further, it is preferable that the monomer (a) and the radical polymerization initiator are continuously supplied so as to be uniform in the reaction vessel.
〔１－２．共重合体（Ｂ）〕
［１－２－１．共重合体（Ｂ）に含まれる構造単位］
　共重合体（Ｂ）は、下記式（１）で表される第２１構造単位と、下記式（２）で表される第２２構造単位と、下記式（３）で表される第２３構造単位と、を有する。共重合体（Ｂ）は、１分子中にエチレン性不飽和結合を複数有することが好ましい。共重合体（Ｂ）は、第２１構造単位、第２２構造単位、及び第２３構造単位のいずれにも該当しない構造単位を含んでもよい。 [1-2. Copolymer (B)]
[1-2-1. Structural unit contained in the copolymer (B)]
The copolymer (B) has a 21st structural unit represented by the following formula (1), a 22nd structural unit represented by the following formula (2), and a 23rd structure represented by the following formula (3). It has a unit and. The copolymer (B) preferably has a plurality of ethylenically unsaturated bonds in one molecule. The copolymer (B) may contain a structural unit that does not fall under any of the 21st structural unit, the 22nd structural unit, and the 23rd structural unit.
　なお、共重合体（Ｂ）において、構造単位の構成について述べる際には、特に断りがなければ末端構造は考慮しない。例えば、共重合体（Ｂ）における、ある構造単位の含有率については、特に断りがなければ、末端構造を除く構造中のその構造単位の含有率である。また、共重合体（Ｂ）が、ある構造単位からなるとされる場合、その構造単位以外に末端構造を含んでもよい。ここで共重合体（Ｂ）における末端構造とは、分子末端に最も近いエーテル結合よりも分子末端側にあり、かつ下記の式（１）～（３）のいずれの構造中にも含まれない構造である。さらに、末端構造中には下記の式（１）～（３）に示される構造は含まれない。 In the copolymer (B), the terminal structure is not considered unless otherwise specified when describing the structure of the structural unit. For example, the content of a certain structural unit in the copolymer (B) is the content of the structural unit in the structure excluding the terminal structure unless otherwise specified. Further, when the copolymer (B) is composed of a certain structural unit, it may contain a terminal structure in addition to the structural unit. Here, the terminal structure in the copolymer (B) is on the molecular terminal side of the ether bond closest to the molecular terminal, and is not included in any of the structures of the following formulas (1) to (3). It is a structure. Further, the terminal structure does not include the structures represented by the following formulas (1) to (3).
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000014
Figure JPOXMLDOC01-appb-C000014
　式（２）において、Ｒ１は、分岐を有してもよい炭素数１以上６以下のアルキル基である。Ｒ１は、炭素数４以下であることが好ましく、炭素数２以下であることがより好ましく、メチル基であることがさらに好ましい。 In the formula (2), R 1 is an alkyl group having 1 or more and 6 or less carbon atoms which may have a branch. R 1 preferably has 4 or less carbon atoms, more preferably 2 or less carbon atoms, and even more preferably a methyl group.
Figure JPOXMLDOC01-appb-C000015
Figure JPOXMLDOC01-appb-C000015
　式（３）において、Ｒ２は、エチレン性不飽和結合を有する基である。Ｒ２は、ビニルオキシ基（－ＯＣＨ２＝ＣＨ２）、アリルオキシ基（－ＯＣＨ２－ＣＨ２＝ＣＨ２）、（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、及び－ＯＣＨ２－ＣＨ２－ＣＨ２＝ＣＨ２からなる群より選ばれる少なくともいずれか１つを有することが好ましく、アリルオキシ基、（メタ）アクリロイル基、及び（メタ）アクリロイルオキシ基からなる群より選ばれる少なくともいずれか１つを有することがより好ましく、アリルオキシ基を有することがさらに好ましい。１つの第２３構造単位に含まれるエチレン性不飽和結合は、１個であることが好ましい。 In formula (3), R 2 is a group having an ethylenically unsaturated bond. R2 is a vinyloxy group (-OCH 2 = CH 2 ), an allyloxy group (-OCH 2 -CH 2 = CH 2 ), a (meth) acryloyl group, a (meth) acryloyloxy group, and -OCH 2 -CH 2- . It is preferable to have at least one selected from the group consisting of CH 2 = CH 2 , and at least one selected from the group consisting of an allyloxy group, a (meth) acryloyl group, and a (meth) acryloyloxy group. It is more preferable to have it, and it is further preferable to have an allyloxy group. The number of ethylenically unsaturated bonds contained in one 23rd structural unit is preferably one.
　Ｒ２の構造は、下記式（４）で表されることが好ましい。 The structure of R2 is preferably represented by the following formula (4).
Figure JPOXMLDOC01-appb-C000016
Figure JPOXMLDOC01-appb-C000016
　式（４）において、Ｒ２１は分岐を有してもよい炭素数１～５のアルキレン基、Ｒ２２は、ビニルオキシ基、アリルオキシ基、（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、及び－ＯＣＨ２－ＣＨ２－ＣＨ２＝ＣＨ２のうちいずれか１つである。 In formula (4), R 21 is an alkylene group having 1 to 5 carbon atoms which may have a branch, and R 22 is a vinyloxy group, an allyloxy group, a (meth) acryloyl group, a (meth) acryloyloxy group, and-. OCH 2 -CH 2 -CH 2 = CH 2 is any one of them.
　式（４）において、Ｒ２１は炭素数１または２のアルキレン基であることが好ましく、メチレン基であることがより好ましい。式（４）において、Ｒ２２は、アリルオキシ基、（メタ）アクリロイル基、及び（メタ）アクリロイルオキシ基のうちいずれか１つであることがより好ましく、アリルオキシ基であることがさらに好ましい。 In the formula (4), R 21 is preferably an alkylene group having 1 or 2 carbon atoms, and more preferably a methylene group. In the formula (4), R 22 is more preferably any one of an allyloxy group, a (meth) acryloyl group, and a (meth) acryloyloxy group, and even more preferably an allyloxy group.
［１－２－２．共重合体（Ｂ）に含まれる各構造単位の含有率］
　共重合体（Ｂ）における、第２１構造単位及び第２２構造単位の含有量を調整することで、共重合体（Ｂ）の親水性を適切な範囲にコントロールできる。例えば、共重合体（Ｂ）における第２１構造単位の含有量を増やせば、共重合体（Ｂ）の親水性は向上し、第２１構造単位の含有量を減らせば、共重合体（Ｂ）の親水性は低下する。 [1-2-2. Content of each structural unit contained in the copolymer (B)]
By adjusting the contents of the 21st structural unit and the 22nd structural unit in the copolymer (B), the hydrophilicity of the copolymer (B) can be controlled in an appropriate range. For example, if the content of the 21st structural unit in the copolymer (B) is increased, the hydrophilicity of the copolymer (B) is improved, and if the content of the 21st structural unit is decreased, the copolymer (B) is used. The hydrophilicity of is reduced.
　共重合体（Ｂ）における、第２１構造単位及び第２２構造単位の含有量を調整することで、共重合体（Ｂ）の結晶性を適切な範囲に調整し、共重合体（Ｂ）の結晶性をコントロールできる。例えば、共重合体（Ｂ）における第２１構造単位の含有量を増やせば、共重合体（Ｂ）の結晶性は向上し、第２１構造単位の含有量を減らせば、共重合体（Ｂ）の結晶性は低下する。 By adjusting the contents of the 21st structural unit and the 22nd structural unit in the copolymer (B), the crystallinity of the copolymer (B) can be adjusted to an appropriate range, and the copolymer (B) can be adjusted. Crystallinity can be controlled. For example, if the content of the 21st structural unit in the copolymer (B) is increased, the crystallinity of the copolymer (B) is improved, and if the content of the 21st structural unit is decreased, the copolymer (B) is used. Crystallinity is reduced.
　以下、共重合体（Ｂ）に含まれるこれらの構造単位の含有量の関係について説明する。 Hereinafter, the relationship between the contents of these structural units contained in the copolymer (B) will be described.
　共重合体（Ｂ）において、全構造単位中の、第２１構造単位の含有率は、５．０モル％以上であり、１８モル％以上であることが好ましく、２５モル％以上であることがより好ましい。共重合体（Ｂ）において、全構造単位中の、第２１構造単位の含有率は、９８モル％以下であり、９７モル％以下であることが好ましい。 In the copolymer (B), the content of the 21st structural unit in the total structural units is 5.0 mol% or more, preferably 18 mol% or more, and preferably 25 mol% or more. More preferred. In the copolymer (B), the content of the 21st structural unit in the total structural units is 98 mol% or less, preferably 97 mol% or less.
　共重合体（Ｂ）において、全構造単位中の、第２２構造単位の含有率は、０．３０モル％以上であり、０．５０モル％以上であることが好ましく、０．７０モル％以上であることがより好ましい。共重合体（Ｂ）において、全構造単位中の、第２２構造単位の含有率は、９０モル％以下であり、８０モル％以下であることが好ましく、７５モル％以下であることがより好ましい。 In the copolymer (B), the content of the 22nd structural unit in all the structural units is 0.30 mol% or more, preferably 0.50 mol% or more, preferably 0.70 mol% or more. Is more preferable. In the copolymer (B), the content of the 22nd structural unit in the total structural units is 90 mol% or less, preferably 80 mol% or less, and more preferably 75 mol% or less. ..
　共重合体（Ｂ）において、全構造単位中の、第２３構造単位の含有率は、０．３０モル％以上であり、０．５０モル％以上であることが好ましく、０．７０モル％以上であることがより好ましい。共重合体（Ｂ）において、全構造単位中の、第２３構造単位の含有率は、１０モル％以下であり、６．０モル％以下であることが好ましく、４．５モル％以下であることがより好ましい。 In the copolymer (B), the content of the 23rd structural unit in all the structural units is 0.30 mol% or more, preferably 0.50 mol% or more, preferably 0.70 mol% or more. Is more preferable. In the copolymer (B), the content of the 23rd structural unit in the total structural units is 10 mol% or less, preferably 6.0 mol% or less, and preferably 4.5 mol% or less. Is more preferable.
　共重合体（Ｂ）における、全構造単位中の、第２１構造単位、第２２構造単位、及び第２３構造単位の合計含有率は、９０質量％以上であり、９５質量％以上であることが好ましく、９８質量％以上であることがより好ましく、１００質量％であることが最も好ましい。 The total content of the 21st structural unit, the 22nd structural unit, and the 23rd structural unit in the total structural unit of the copolymer (B) is 90% by mass or more, and 95% by mass or more. It is more preferably 98% by mass or more, and most preferably 100% by mass.
　なお、共重合体（Ｂ）を構成する構造単位には、末端構造（定義は上記の通り）は含まない。この点については、以下に述べる第１の形態にかかる共重合体（Ｂ１）、及び第２の形態にかかる共重合体（Ｂ２）についても同様である。 The structural unit constituting the copolymer (B) does not include the terminal structure (definition is as described above). The same applies to the copolymer (B1) according to the first form and the copolymer (B2) according to the second form described below.
［１－２－３．共重合体（Ｂ）の形態］
　共重合体（Ｂ）として、親水性の異なる以下の２つの好ましい形態が挙げられる。以下これらの形態を、第１の形態にかかる共重合体（Ｂ１）、及び第２の形態にかかる共重合体（Ｂ２）として説明する。第２の形態にかかる共重合体（Ｂ２）の方が第１の形態にかかる共重合体（Ｂ１）よりも親水性が高い。 [1-2-3. Form of copolymer (B)]
Examples of the copolymer (B) include the following two preferable forms having different hydrophilicity. Hereinafter, these forms will be described as the copolymer (B1) according to the first form and the copolymer (B2) according to the second form. The copolymer (B2) according to the second form is more hydrophilic than the copolymer (B1) according to the first form.
［１－２－４．共重合体（Ｂ１）（第１の形態）］
　共重合体（Ｂ１）において、全構造単位中の、第２１構造単位の含有率は、５．０モル％以上であることが好ましく、１８モル％以上であることがより好ましく、２５モル％以上であることがさらに好ましい。共重合体（Ｂ１）において、全構造単位中の、第２１構造単位の含有率は、５０モル％以下であることが好ましく、４０モル％以下であることがより好ましい。 [1-2-4. Copolymer (B1) (first form)]
In the copolymer (B1), the content of the 21st structural unit in the total structural units is preferably 5.0 mol% or more, more preferably 18 mol% or more, and 25 mol% or more. Is more preferable. In the copolymer (B1), the content of the 21st structural unit in the total structural units is preferably 50 mol% or less, more preferably 40 mol% or less.
　共重合体（Ｂ１）において、全構造単位中の、第２２構造単位の含有率は、４０モル％以上であることが好ましく、５０モル％以上であることがより好ましく、６０モル％以上であることがさらに好ましい。共重合体（Ｂ１）において、全構造単位中の、第２２構造単位の含有率は、９０モル％以下であることが好ましく、８０モル％以下であることがより好ましく、７５モル％以下であることがさらに好ましい。 In the copolymer (B1), the content of the 22nd structural unit in the total structural units is preferably 40 mol% or more, more preferably 50 mol% or more, and more preferably 60 mol% or more. Is even more preferable. In the copolymer (B1), the content of the 22nd structural unit in the total structural units is preferably 90 mol% or less, more preferably 80 mol% or less, and 75 mol% or less. Is even more preferable.
　共重合体（Ｂ１）において、全構造単位中の、第２３構造単位の含有率は、０．３０モル％以上であることが好ましく、０．５０モル％以上であることがより好ましく、０．７０モル％以上であることがさらに好ましい。共重合体（Ｂ１）において、全構造単位中の、第２３構造単位の含有率は、１０モル％以下であることが好ましく、６．０モル％以下であることがより好ましく、４．５モル％以下であることがさらに好ましい。 In the copolymer (B1), the content of the 23rd structural unit in all the structural units is preferably 0.30 mol% or more, more preferably 0.50 mol% or more, and 0. It is more preferably 70 mol% or more. In the copolymer (B1), the content of the 23rd structural unit in the total structural units is preferably 10 mol% or less, more preferably 6.0 mol% or less, and 4.5 mol. It is more preferably% or less.
［１－２－５．共重合体（Ｂ２）（第２の形態）］
　共重合体（Ｂ２）において、全構造単位中の、第２１構造単位の含有率は、７０モル％以上であることが好ましく、８０モル％以上であることがより好ましく、９０モル％以上であることがさらに好ましい。共重合体（Ｂ２）において、全構造単位中の、第２１構造単位の含有率は、９８モル％以下であることが好ましく、９７モル％以下であることがより好ましい。 [1-2-5. Copolymer (B2) (second form)]
In the copolymer (B2), the content of the 21st structural unit in the total structural units is preferably 70 mol% or more, more preferably 80 mol% or more, and more preferably 90 mol% or more. Is even more preferable. In the copolymer (B2), the content of the 21st structural unit in the total structural units is preferably 98 mol% or less, more preferably 97 mol% or less.
　共重合体（Ｂ２）において、全構造単位中の、第２２構造単位の含有率は、０．３０モル％以上であることが好ましく、０．５０モル％以上であることがより好ましく、０．７０モル％以上であることがさらに好ましい。共重合体（Ｂ２）において、全構造単位中の、第２２構造単位の含有率は、２０モル％以下であることが好ましく、１５モル％以下であることがより好ましく、１０モル％以下であることがさらに好ましい。 In the copolymer (B2), the content of the 22nd structural unit in the total structural units is preferably 0.30 mol% or more, more preferably 0.50 mol% or more, and 0. It is more preferably 70 mol% or more. In the copolymer (B2), the content of the 22nd structural unit in the total structural units is preferably 20 mol% or less, more preferably 15 mol% or less, and 10 mol% or less. Is even more preferable.
　共重合体（Ｂ２）において、全構造単位中の、第２３構造単位の含有率は、０．３０モル％以上であることが好ましく、０．５０モル％以上であることがより好ましく、０．７０モル％以上であることがさらに好ましい。共重合体（Ｂ２）において、全構造単位中の、第２３構造単位の含有率は、１０モル％以下であることが好ましく、６．０モル％以下であることがより好ましく、４．５モル％以下であることがさらに好ましい。 In the copolymer (B2), the content of the 23rd structural unit in the total structural units is preferably 0.30 mol% or more, more preferably 0.50 mol% or more, and 0. It is more preferably 70 mol% or more. In the copolymer (B2), the content of the 23rd structural unit in the total structural units is preferably 10 mol% or less, more preferably 6.0 mol% or less, and 4.5 mol. It is more preferably% or less.
［１－２－６．共重合体（Ｂ）の構造］
　共重合体（Ｂ）は、第２１構造単位からなる第１ブロック、第２２構造単位からなる第２ブロック、及び第２３構造単位からなる第３ブロックを有するブロック共重合体であることが好ましい。共重合体（Ｂ）は、第１ブロック、第２ブロック、及び第３ブロックからなる（ただし、上記定義の通り末端構造は含んでもよい）３元ブロック共重合体であることがより好ましい。共重合体（Ｂ）は、第１ブロック、第２ブロック、及び第３ブロックがその順に配列された（すなわち、第１ブロックと、第３ブロックとの間に第２ブロックが存在する）３元ブロック共重合体であることがさらに好ましい。 [1-2-6. Structure of copolymer (B)]
The copolymer (B) is preferably a block copolymer having a first block composed of the 21st structural unit, a second block composed of the 22nd structural unit, and a third block composed of the 23rd structural unit. The copolymer (B) is more preferably a ternary block copolymer composed of a first block, a second block, and a third block (however, the terminal structure may be included as defined above). The copolymer (B) is a ternary in which the first block, the second block, and the third block are arranged in that order (that is, the second block exists between the first block and the third block). It is more preferably a block copolymer.
　共重合体（Ｂ）の重量平均分子量の好ましい範囲は、共重合体（Ｂ）の水溶性の有無によって異なる。共重合体（Ｂ）を、０．１Ｍ　ＮａＮＯ３水溶液に溶解させて、共重合体（Ｂ）を０．１質量％含む水溶液の作製が可能である場合、共重合体（Ｂ）の重量平均分子量は、以下に示す条件の水系ＧＰＣで測定したプルラン換算値である。 The preferred range of the weight average molecular weight of the copolymer (B) depends on the presence or absence of water solubility of the copolymer (B). When the copolymer (B) can be dissolved in a 0.1 M NaNO 3 aqueous solution to prepare an aqueous solution containing 0.1% by mass of the copolymer (B), the weight average of the copolymer (B) The molecular weight is a pull-run conversion value measured by an aqueous GPC under the conditions shown below.
（水系ＧＰＣ）
　ＧＰＣ装置：ＧＰＣ‐１０１（昭和電工（株）製）
　溶媒：０．１Ｍ　ＮａＮＯ３水溶液
　サンプルカラム：Ｓｈｏｄｅｘ　Ｃｏｌｕｍｎ　Ｏｈｐａｋ　ＳＢ－８０６　ＨＱ（８．０ｍｍＩ．Ｄ．　ｘ　３００ｍｍ）　×２
　リファレンスカラム：Ｓｈｏｄｅｘ　Ｃｏｌｕｍｎ　Ｏｈｐａｋ　ＳＢ－８００　ＲＬ（８．０ｍｍＩ．Ｄ．　ｘ　３００ｍｍ）　×２
　カラム温度：４０℃
　サンプル濃度：０．１質量％
　検出器：ＲＩ－７１Ｓ（株式会社島津製作所製）
　流量：１ｍｌ／ｍｉｎ
　分子量スタンダード：プルラン（Ｐ‐５、Ｐ－１０、Ｐ‐２０、Ｐ－５０、Ｐ‐１００、Ｐ－２００、Ｐ－４００、Ｐ－８００、Ｐ－１３００、Ｐ－２５００（昭和電工株式会社製）） (Water-based GPC)
GPC device: GPC-101 (manufactured by Showa Denko KK)
Solvent: 0.1M NaNO 3 aqueous solution Sample column: Shodex Volume Ohpak SB-806 HQ (8.0 mm ID x 300 mm) x 2
Reference column: Shodex Colon Ohpak SB-800 RL (8.0 mm ID x 300 mm) x 2
Column temperature: 40 ° C
Sample concentration: 0.1% by mass
Detector: RI-71S (manufactured by Shimadzu Corporation)
Flow rate: 1 ml / min
Molecular weight standard: Pullulan (P-5, P-10, P-20, P-50, P-100, P-200, P-400, P-800, P-1300, P-2500 (manufactured by Showa Denko KK) )))
　この場合、共重合体（Ｂ）の重量平均分子量Ｍｗ（プルラン換算値）は、１００００以上であることが好ましく、３００００以上であることがより好ましく、５００００以上であることがさらに好ましい。電極の強度が向上するためである。また、この場合、共重合体（Ｂ）の重量平均分子量Ｍｗ（プルラン換算値）は、３０００００以下であることが好ましく、２０００００以下であることがより好ましく、１２００００以下であることがさらに好ましい。後述する電極スラリーにおける固形分の分散性が向上するためである。 In this case, the weight average molecular weight M w (pullulan equivalent value) of the copolymer (B) is preferably 10,000 or more, more preferably 30,000 or more, and further preferably 50,000 or more. This is because the strength of the electrode is improved. Further, in this case, the weight average molecular weight M w (pullulan equivalent value) of the copolymer (B) is preferably 300,000 or less, more preferably 200,000 or less, and further preferably 120,000 or less. This is because the dispersibility of the solid content in the electrode slurry described later is improved.
　共重合体（Ｂ）を、０．１Ｍ　ＮａＮＯ３水溶液に溶解させて、共重合体（Ｂ）を０．１質量％含む水溶液を作製することが不可能である場合、共重合体（Ｂ）の重量平均分子量は、以下に示す条件の溶剤系ＧＰＣで測定したポリスチレン換算値である。 When it is impossible to dissolve the copolymer (B) in a 0.1 M NaNO 3 aqueous solution to prepare an aqueous solution containing 0.1% by mass of the copolymer (B), the copolymer (B) is used. The weight average molecular weight of the above is a polystyrene-equivalent value measured by a solvent-based GPC under the conditions shown below.
（溶剤系ＧＰＣ）
　ＧＰＣ装置：Ｗａｔｅｒｓ　ＧＰＣ　Ｓｙｓｔｅｍ　ｅ２６９５
　溶媒：テトラヒドロフラン
　カラム：ＳＨＯＤＥＸ　ＫＦ－８０６Ｌ　×２、ＳＨＯＤＥＸ　ＫＦ－Ｇ（昭和電工（株）製））カラム温度：４０℃
　カラム温度：４０℃
　サンプル濃度：０．２質量％
　検出器：Ｗａｔｅｒｓ　２４１４ＲＩ
　流量：０．６５ｍＬ／ｍｉｎ
　分子量スタンダード：ポリスチレン（Ｓｈｏｄｅｘ　Ｐｏｌｙｓｔｙｒｅｎｅ　ＳＴＡＮＤＡＲＤ　ＳＬ－１０５、ＳＭ－１０５（昭和電工株式会社製）） (Solvent-based GPC)
GPC device: Waters GPC System e2695
Solvent: Tetrahydrofuran Column: SHODEX KF-806L x 2, SHODEX KF-G (manufactured by Showa Denko KK) Column temperature: 40 ° C.
Column temperature: 40 ° C
Sample concentration: 0.2% by mass
Detector: Waters 2414RI
Flow rate: 0.65 mL / min
Molecular weight standard: Polystyrene (Shodex Polystyrene STANDARD SL-105, SM-105 (manufactured by Showa Denko KK))
　この場合、共重合体（Ｂ）の重量平均分子量Ｍｗ（ポリスチレン換算値）は、１００００以上であることが好ましく、２００００以上であることがより好ましく、３００００以上であることがさらに好ましい。電極の強度が向上するためである。また、この場合、共重合体（Ｂ）の重量平均分子量Ｍｗ（ポリスチレン換算値）は、２０００００以下であることが好ましく、１５００００以下であることがより好ましく、８００００以下であることがさらに好ましい。後述する電極スラリーにおける固形分の分散性が向上するためである。 In this case, the weight average molecular weight M w (polystyrene equivalent value) of the copolymer (B) is preferably 10,000 or more, more preferably 20,000 or more, and further preferably 30,000 or more. This is because the strength of the electrode is improved. Further, in this case, the weight average molecular weight M w (polystyrene equivalent value) of the copolymer (B) is preferably 200,000 or less, more preferably 150,000 or less, and further preferably 80,000 or less. This is because the dispersibility of the solid content in the electrode slurry described later is improved.
［１－２－７．共重合体（Ｂ）の具体例］
　共重合体（Ｂ）は、例えば、以下の式（５）で表される３元ブロック共重合体であることが好ましい。 [1-2-7. Specific example of copolymer (B)]
The copolymer (B) is preferably, for example, a ternary block copolymer represented by the following formula (5).
Figure JPOXMLDOC01-appb-C000017
Figure JPOXMLDOC01-appb-C000017
　式（５）において、ｎ：ｍ：ｌ＝５．０～９８：０．３０～９０：０．３０～４．５、ｎ：ｍ：ｌ＝１８～９７：０．５０～８０：０．５０～６．０であることが好ましく、ｎ：ｍ：ｌ＝２５～９７：０．７０～７５：０．８０～４．５であることがより好ましい。重量平均分子量の好ましい範囲については上記の通りである。 In the formula (5), n: m: l = 5.0 to 98: 0.30 to 90: 0.30 to 4.5, n: m: l = 18 to 97: 0.50 to 80: 0. It is preferably 50 to 6.0, and more preferably n: m: l = 25 to 97: 0.70 to 75: 0.80 to 4.5. The preferred range of weight average molecular weight is as described above.
　上記式（５）で表される共重合体の第１の形態は、ｎ：ｍ：ｌ＝５．０～５０：４０～９０：０．３０～４．５であり、ｎ：ｍ：ｌ＝１８～４０：５０～８０：０．５０～６であることが好ましく、ｎ：ｍ：ｌ＝２５～４０：６０～７５：０．８０～４．５であることがより好ましい。０．１Ｍ　ＮａＮＯ３水溶液に溶解させて、第１の形態にかかる共重合体を０．１質量％含む水溶液の作製が不可能である場合、重量平均分子量はポリスチレン換算で１００００～２０００００であり、２００００～１５００００であることが好ましく、３００００～８００００であることがより好ましい。 The first form of the copolymer represented by the above formula (5) is n: m: l = 5.0 to 50:40 to 90: 0.30 to 4.5, and n: m: l. = 18-40: 50-80: 0.50-6, more preferably n: m: l = 25-40: 60-75: 0.80-4.5. When it is impossible to prepare an aqueous solution containing 0.1% by mass of the copolymer according to the first embodiment by dissolving it in a 0.1 M NaNO 3 aqueous solution, the weight average molecular weight is 10,000 to 200,000 in terms of polystyrene. It is preferably 20,000 to 150,000, more preferably 30,000 to 80,000.
　第１の形態について、より具体的な共重合体として、式（５）において、ｎ：ｍ：ｌ＝３０：６９：１．０、Ｍｗ＝５００００である共重合体（Ｂ２－１）が挙げられる。 Regarding the first embodiment, as a more specific copolymer, the copolymer (B2-1) having n: m: l = 30: 69: 1.0 and Mw = 50,000 in the formula (5) is mentioned. Be done.
　上記式（５）で表される共重合体の第２の形態は、ｎ：ｍ：ｌ＝７０～９８：０．３０～２０：０．３０～１０であり、ｎ：ｍ：ｌ＝８０～９７：０．５０～１５：０．５０～６．０であることが好ましく、ｎ：ｍ：ｌ＝９０～９７：０．７０～１０：０．８０～４．５、Ｍｗ＝５００００～８００００であることがより好ましい。０．１Ｍ　ＮａＮＯ３水溶液に溶解させて、第２の形態にかかる共重合体を０．１質量％含む水溶液の作製が可能である場合、重量平均分子量はプルラン換算で１００００～３０００００であり、３００００～２０００００であることが好ましく、５００００～１２００００であることがより好ましい。 The second form of the copolymer represented by the above formula (5) is n: m: l = 70 to 98: 0.30 to 20: 0.30 to 10, and n: m: l = 80. It is preferably from 97: 0.50 to 15: 0.50 to 6.0, n: m: l = 90 to 97: 0.70 to 10: 0.80 to 4.5, Mw = 50,000 to It is more preferably 80,000. When it is possible to prepare an aqueous solution containing 0.1% by mass of the copolymer according to the second embodiment by dissolving it in a 0.1 M NaNO 3 aqueous solution, the weight average molecular weight is 10,000 to 300,000 in terms of pullulan, which is 30,000. It is preferably about 200,000, more preferably 50,000 to 120,000.
　第２の形態について、より具体的な重合体として、式（５）において、ｎ：ｍ：ｌ＝９３：６．０：１．０、Ｍｗ＝８０，０００である共重合体（Ｂ２－２）、及びｎ：ｍ：ｌ＝９６：１．０：３．０、Ｍｗ＝８０，０００である共重合体（Ｂ２－３）が挙げられる。 Regarding the second embodiment, as a more specific polymer, a copolymer (B2-2) having n: m: l = 93: 6.0: 1.0 and Mw = 80,000 in the formula (5). ), And a copolymer (B2-3) having n: m: l = 96: 1.0: 3.0 and Mw = 80,000.
［１－２－８．共重合体（Ｂ）の合成方法］
　共重合体（Ｂ）の合成方法は、特に限定されないが、例えば、酸触媒を用いたエポキシドの開環重合により得られる。また、触媒としてトリアルキルアルミニウム、水酸化物、アルカリ金属アルコキシド等を用いてもよい。共重合体（Ｂ）をブロック共重合体とする場合、それぞれの構造単位に対応する単量体を、１種類ずつ順番に重合することが好ましい。この場合、重合する順番は所望の配列に対応させることが好ましい。重合は水性媒体中で行うことが好ましく、用いることができる水性媒体については上述した水性媒体（ｂ）と同様であるが、共重合体（Ａ）の合成に用いた水性媒体と異なっていてもよい。 [1-2-8. Method for synthesizing copolymer (B)]
The method for synthesizing the copolymer (B) is not particularly limited, but it can be obtained, for example, by ring-opening polymerization of the epoxide using an acid catalyst. Further, trialkylaluminum, hydroxide, alkali metal alkoxide and the like may be used as the catalyst. When the copolymer (B) is used as a block copolymer, it is preferable to polymerize the monomers corresponding to the respective structural units one by one in order. In this case, it is preferable that the order of polymerization corresponds to a desired sequence. The polymerization is preferably carried out in an aqueous medium, and the aqueous medium that can be used is the same as the aqueous medium (b) described above, but may be different from the aqueous medium used for synthesizing the copolymer (A). good.
［１－３．共重合体（Ａ）及び共重合体（Ｂ）の質量比］
　本発明にかかる電極バインダーにおいて、共重合体（Ａ）と共重合体（Ｂ）との質量比（共重合体（Ａ）／共重合体（Ｂ））は、５０．０／５０．０以上であり、５３．０／４７．０以上であることが好ましく、６４．０／３６．０以上であることがより好ましく、７７．０／２３．０以上であることがさらに好ましい。本発明にかかる電極バインダーを含む電極活物質層の集電体に対する剥離強度が向上するためである。また、この電極活物質層を電極に備えた非水系二次電池のサイクル特性が向上するためである。 [1-3. Mass ratio of copolymer (A) and copolymer (B)]
In the electrode binder according to the present invention, the mass ratio of the copolymer (A) to the copolymer (B) (polymer (A) / copolymer (B)) is 50.0 / 50.0 or more. It is preferably 53.0 / 47.0 or more, more preferably 64.0 / 36.0 or more, and even more preferably 77.0 / 23.0 or more. This is because the peel strength of the electrode active material layer containing the electrode binder according to the present invention to the current collector is improved. Further, this is because the cycle characteristics of the non-aqueous secondary battery provided with the electrode active material layer on the electrode are improved.
　本発明にかかる電極バインダーにおいて、共重合体（Ａ）と共重合体（Ｂ）との質量比（共重合体（Ａ）／共重合体（Ｂ））は、９９．０／１．０以下であり、９７．５／２．５以下であることが好ましく、９６．５／３．５以下であることがより好ましく、９３．０／７．０以下であることがさらに好ましい。本発明にかかる電極バインダーを含む電極活物質層を電極に備えた非水系二次電池の内部抵抗が低下する、及び非水系二次電池のサイクル特性が向上するためである。また、非水系二次電池の内部抵抗をさらに低下させる場合、上記質量比は８８．０／１２．０以下であることがさらに好ましい。 In the electrode binder according to the present invention, the mass ratio of the copolymer (A) to the copolymer (B) (copolymer (A) / copolymer (B)) is 99.0 / 1.0 or less. It is preferably 97.5 / 2.5 or less, more preferably 96.5 / 3.5 or less, and further preferably 93.0 / 7.0 or less. This is because the internal resistance of the non-aqueous secondary battery provided with the electrode active material layer containing the electrode binder according to the present invention is reduced, and the cycle characteristics of the non-aqueous secondary battery are improved. Further, when the internal resistance of the non-aqueous secondary battery is further reduced, the mass ratio is more preferably 88.0 / 12.0 or less.
＜２．非水系二次電池電極バインダー組成物＞
　本実施形態の非水系二次電池電極バインダー組成物（以下、バインダー組成物とすることもある）は、共重合体（Ａ）及び共重合体（Ｂ）を含む電極バインダーと、水性媒体（Ｃ）とを含む。本実施形態の非水系二次電池電極バインダー組成物は、本実施形態の非水系二次電池電極用バインダー組成物である。バインダー組成物において、共重合体（Ａ）は、水性媒体（Ｃ）中に分散していることが好ましい。共重合体（Ｂ）は、水性媒体（Ｃ）中に分散していてもよく、溶解していてもよい。バインダー組成物は、これらの成分の他に、例えば、本発明にかかる電極バインダーの作製に用いた成分、本発明にかかる電極バインダー以外のバインダー、共重合体（Ａ）にも共重合体（Ｂ）にも該当しない重合体、界面活性剤等を含んでもよい。 <2. Non-aqueous secondary battery electrode binder composition>
The non-aqueous secondary battery electrode binder composition of the present embodiment (hereinafter, may be referred to as a binder composition) includes an electrode binder containing the copolymer (A) and the copolymer (B), and an aqueous medium (C). ) And. The non-aqueous secondary battery electrode binder composition of the present embodiment is the binder composition for the non-aqueous secondary battery electrode of the present embodiment. In the binder composition, the copolymer (A) is preferably dispersed in the aqueous medium (C). The copolymer (B) may be dispersed or dissolved in the aqueous medium (C). In addition to these components, the binder composition includes, for example, a component used for producing the electrode binder according to the present invention, a binder other than the electrode binder according to the present invention, and a copolymer (B) as well as the copolymer (A). ) May also be contained, such as a polymer and a surfactant.
　水性媒体（Ｃ）については上述した水性媒体（ｂ）と同様であるが、共重合体（Ａ）の合成に用いた水性媒体、及び共重合体（Ｂ）の合成に用いた水性媒体と異なっていてもよい。 The aqueous medium (C) is the same as the aqueous medium (b) described above, but is different from the aqueous medium used for the synthesis of the copolymer (A) and the aqueous medium used for the synthesis of the copolymer (B). May be.
　バインダー組成物における、不揮発分中の、本発明にかかる電極バインダーの含有率は、８０質量％以上であることが好ましく、９０質量％以上であることがより好ましく、９５質量％以上であることがさらに好ましく、９８質量％以上であることがさらに好ましい。電極バインダーによる本発明の目的とする効果への寄与を大きくするためである。 The content of the electrode binder according to the present invention in the non-volatile content in the binder composition is preferably 80% by mass or more, more preferably 90% by mass or more, and more preferably 95% by mass or more. It is more preferably 98% by mass or more, and even more preferably 98% by mass or more. This is to increase the contribution of the electrode binder to the desired effect of the present invention.
　バインダー組成物の不揮発分濃度は、２０質量％以上であることが好ましく、２５質量％以上であることがより好ましく、３０質量％以上であることがさらに好ましい。バインダー組成物中に含まれる有効成分の量を多くするためである。バインダー組成物の不揮発分濃度は、水性媒体（Ｃ）の量により調整できる。 The non-volatile content concentration of the binder composition is preferably 20% by mass or more, more preferably 25% by mass or more, and further preferably 30% by mass or more. This is to increase the amount of the active ingredient contained in the binder composition. The non-volatile content concentration of the binder composition can be adjusted by the amount of the aqueous medium (C).
　バインダー組成物の不揮発分濃度は、８０質量％以下であることが好ましく、７０質量％以下であることがより好ましく、６０質量％以下であることがさらに好ましい。バインダー組成物の粘度の上昇を抑制し、後述するスラリーを作製しやすくするためである。 The non-volatile content concentration of the binder composition is preferably 80% by mass or less, more preferably 70% by mass or less, and further preferably 60% by mass or less. This is to suppress an increase in the viscosity of the binder composition and facilitate the production of a slurry described later.
　バインダー組成物の製造方法の一例としては、共重合体（Ａ）を含む混合液と、共重合体（Ｂ）を含む混合液とを混合し、必要に応じてその他の成分を添加する方法が挙げられる。バインダー組成物の製造方法の別の一例としては、共重合体（Ａ）及び共重合体（Ｂ）のうち一方を混合液として、他方を粉末等の固体として添加し、必要に応じてその他の成分を添加する方法が挙げられる。バインダー組成物の製造方法の別の一例としては、共重合体（Ａ）及び共重合体（Ｂ）を固体として混合し、水性媒体（Ｃ）に加え、必要に応じてその他の成分を添加する方法が挙げられる。なお、バインダー組成物の製造方法はここで挙げた例に限られない。 As an example of a method for producing a binder composition, a method of mixing a mixed solution containing the copolymer (A) and a mixed solution containing the copolymer (B) and adding other components as necessary is used. Can be mentioned. As another example of the method for producing the binder composition, one of the copolymer (A) and the copolymer (B) is added as a mixed solution, and the other is added as a solid such as powder, and if necessary, the other. Examples include a method of adding an ingredient. As another example of the method for producing the binder composition, the copolymer (A) and the copolymer (B) are mixed as a solid, added to the aqueous medium (C), and if necessary, other components are added. The method can be mentioned. The method for producing the binder composition is not limited to the examples given here.
＜３．非水系二次電池電極スラリー＞
　次に、非水系二次電池電極スラリー（以下、「電極スラリー」とすることもある）について詳述する。非水系二次電池電極スラリーは、非水系二次電池電極用スラリーである。電極スラリーは、本発明にかかる電極バインダーと、電極活物質と、水性媒体と、を含む。電極スラリーにおいて、共重合体（Ａ）は、水性媒体中に分散していることが好ましい。共重合体（Ｂ）は、水性媒体中に分散していてもよく、溶解していてもよい。電極スラリーは、これらの成分の他に、増粘剤、導電助剤、本発明にかかる電極バインダーの作製に用いた成分、本発明にかかる電極バインダー以外のバインダー、共重合体（Ａ）にも共重合体（Ｂ）にも該当しない重合体、界面活性剤等を含んでもよい。 <3. Non-aqueous secondary battery electrode slurry>
Next, the non-aqueous secondary battery electrode slurry (hereinafter, may be referred to as “electrode slurry”) will be described in detail. The non-aqueous secondary battery electrode slurry is a slurry for a non-aqueous secondary battery electrode. The electrode slurry includes an electrode binder according to the present invention, an electrode active material, and an aqueous medium. In the electrode slurry, the copolymer (A) is preferably dispersed in an aqueous medium. The copolymer (B) may be dispersed or dissolved in an aqueous medium. In addition to these components, the electrode slurry can also be used as a thickener, a conductive auxiliary agent, a component used for producing the electrode binder according to the present invention, a binder other than the electrode binder according to the present invention, and a copolymer (A). A polymer, a surfactant, or the like that does not correspond to the copolymer (B) may be contained.
〔３－１．電極バインダーの含有量〕
　電極バインダーの含有量は、電極活物質１００質量部に対して、０．５０質量部以上であることが好ましく、１．０質量部以上であることがより好ましい。電極バインダーによる効果を十分に発現させるためである。 [3-1. Electrode binder content]
The content of the electrode binder is preferably 0.50 part by mass or more, and more preferably 1.0 part by mass or more with respect to 100 parts by mass of the electrode active material. This is to fully exhibit the effect of the electrode binder.
　電極バインダーの含有量は、電極活物質１００質量部に対して、５．０質量部以下であることが好ましく、４．０質量部以下であることがより好ましく、３．０質量部以下であることがさらに好ましい。電極スラリーを用いて作製される電極活物質層において、電極活物質の含有率を高めるためである。 The content of the electrode binder is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and 3.0 parts by mass or less with respect to 100 parts by mass of the electrode active material. Is even more preferable. This is to increase the content of the electrode active material in the electrode active material layer produced by using the electrode slurry.
〔３－２．電極活物質〕
　電極活物質は、リチウムイオン等の電荷キャリアとなるイオンを挿入（Ｉｎｔｅｒｃａｒａｔｉｏｎ）／脱離（Ｄｅｉｎｔｅｒｃａｌａｔｉｏｎ）可能な材料である。電荷キャリアとなるイオンはアルカリ金属イオンであることが好ましく、リチウムイオン、ナトリウムイオン、カリウムイオンであることがより好ましく、リチウムイオンであることがさらに好ましい。 [3-2. Electrode active material]
The electrode active material is a material capable of intercalation / deintercalation of ions that become charge carriers such as lithium ions. The ion serving as a charge carrier is preferably an alkali metal ion, more preferably a lithium ion, a sodium ion, or a potassium ion, and even more preferably a lithium ion.
　電極が負極である場合、電極活物質、すなわち負極活物質は、炭素材料、ケイ素を含む材料、チタンを含む材料のうち少なくともいずれかを含むことが好ましい。電極活物質として用いられる炭素材料としては、例えば、石油コークス、ピッチコークス、石炭コークス等のコークス、有機高分子の炭素化物、人造黒鉛、天然黒鉛等の黒鉛が挙げられる。ケイ素を含む材料としては、例えば、ケイ素単体、酸化ケイ素等のケイ素化合物が挙げられる。チタンを含む材料としては、例えばチタン酸リチウム等が挙げられる。これらの材料は、単独で用いてもよいが、混合あるいは複合化して用いてもよい。 When the electrode is a negative electrode, the electrode active material, that is, the negative electrode active material preferably contains at least one of a carbon material, a material containing silicon, and a material containing titanium. Examples of the carbon material used as the electrode active material include coke such as petroleum coke, pitch coke, and coal coke, carbonized organic polymer, artificial graphite, and graphite such as natural graphite. Examples of the material containing silicon include a simple substance of silicon and a silicon compound such as silicon oxide. Examples of the material containing titanium include lithium titanate and the like. These materials may be used alone, or may be mixed or combined.
　負極活物質は、炭素材料、ケイ素を含む材料のうち少なくともいずれかを含むことが好ましく、炭素材料を含むことがより好ましい。電極バインダーによる電極活物質間、及び電極活物質と集電体との間の結着性を向上させる効果が非常に大きいためである。 The negative electrode active material preferably contains at least one of a carbon material and a material containing silicon, and more preferably contains a carbon material. This is because the effect of the electrode binder on improving the binding property between the electrode active materials and between the electrode active material and the current collector is very large.
　電極が正極である場合、電極活物質、すなわち正極活物質は、負極活物質よりも標準電極電位が貴な物質を用いる。正極活物質としては、Ｎｉ－Ｃｏ－Ｍｎ系のリチウム複合酸化物、Ｎｉ－Ｍｎ－Ａｌ系のリチウム複合酸化物、Ｎｉ－Ｃｏ－Ａｌ系のリチウム複合酸化物などのニッケルを含むリチウム複合酸化物；コバルト酸リチウム（ＬｉＣｏＯ２）；スピネル型マンガン酸リチウム（ＬｉＭｎ２Ｏ４）；オリビン型燐酸鉄リチウム；ＴｉＳ２、ＭｎＯ２、ＭｏＯ３、Ｖ２Ｏ５等のカルコゲン化合物等が挙げられる。正極活物質として、これらの物質は１種で用いてもよく、あるいは２種類以上を組み合わせて用いてもよい。 When the electrode is a positive electrode, the electrode active material, that is, the positive electrode active material, uses a material having a higher standard electrode potential than the negative electrode active material. As the positive electrode active material, a lithium composite oxide containing nickel such as a Ni—Co—Mn-based lithium composite oxide, a Ni—Mn—Al based lithium composite oxide, and a Ni—Co—Al based lithium composite oxide. Lithium cobalt oxide (LiCoO 2 ); Spinel-type lithium manganate (LiMn 2 O 4 ); Olivin-type lithium iron phosphate; TiS 2 , MnO 2 , MoO 3 , V2 O 5 , and the like. As the positive electrode active material, these substances may be used alone or in combination of two or more.
〔３－３．増粘剤〕
　増粘剤としては、カルボキシメチルセルロース（ＣＭＣ）、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース等のセルロース類、セルロース類のアンモニウム塩、セルロース類のアルカリ金属塩、ポリビニルアルコ－ル、ポリビニルピロリドン等が挙げられる。増粘剤は、カルボキシメチルセルロース、カルボキシメチルセルロースのアンモニウム塩、カルボキシメチルセルロースアルカリ金属塩のうち少なくともいずれかを含むことが好ましい。電極スラリー中で電極活物質が分散しやすくなるためである。 [3-3. Thickener]
Examples of the thickener include celluloses such as carboxymethyl cellulose (CMC), hydroxyethyl cellulose and hydroxypropyl cellulose, ammonium salts of celluloses, alkali metal salts of celluloses, polyvinyl alcohol, polyvinylpyrrolidone and the like. The thickener preferably contains at least one of carboxymethyl cellulose, an ammonium salt of carboxymethyl cellulose, and an alkali metal salt of carboxymethyl cellulose. This is because the electrode active material is easily dispersed in the electrode slurry.
　電極スラリーにおける増粘剤の含有量は、電極活物質１００質量部に対して０．５０質量部以上であることが好ましく、０．８０質量部以上であることがより好ましい。電極スラリーを用いて作製される電極活物質層において、電極活物質間、及び電極活物質と集電体との間の結着性を向上させるためである。 The content of the thickener in the electrode slurry is preferably 0.50 part by mass or more, and more preferably 0.80 part by mass or more with respect to 100 parts by mass of the electrode active material. This is to improve the bondability between the electrode active materials and between the electrode active material and the current collector in the electrode active material layer produced by using the electrode slurry.
　電極スラリーにおける増粘剤の含有量は、電極活物質１００質量部に対して３．０質量部以下であることが好ましく、２．０質量部以下であることがより好ましく、１．５質量部以下であることがさらに好ましい。電極スラリーの塗工性が向上するためである。 The content of the thickener in the electrode slurry is preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, and 1.5 parts by mass with respect to 100 parts by mass of the electrode active material. The following is more preferable. This is because the coatability of the electrode slurry is improved.
〔３－４．水性媒体〕
　水性媒体については上述した水性媒体（ｂ）と同様であるが、共重合体（Ａ）の合成に用いた水性媒体、及び共重合体（Ｂ）の合成に用いた水性媒体と異なっていてもよい。 [3-4. Aqueous medium]
The aqueous medium is the same as the aqueous medium (b) described above, but may be different from the aqueous medium used for the synthesis of the copolymer (A) and the aqueous medium used for the synthesis of the copolymer (B). good.
〔３－５．導電助剤〕
　導電助剤としては、カーボンブラック、炭素繊維等を用いることが好ましい。カーボンブラックとしては、ファーネスブラック、アセチレンブラック、デンカブラック（登録商標、デンカ株式会社製）、ケッチェンブラック（登録商標、ケッチェンブラックインターナショナル株式会社製）等が挙げられる。炭素繊維は、カーボンナノチューブ、カーボンナノファイバー等が挙げられ、カーボンナノチューブとしては、気相法炭素繊維であるＶＧＣＦ（登録商標、昭和電工株式会社製）が好ましい例として挙げられる。 [3-5. Conductive aid]
As the conductive auxiliary agent, it is preferable to use carbon black, carbon fiber or the like. Examples of carbon black include furnace black, acetylene black, denka black (registered trademark, manufactured by Denka Co., Ltd.), and Ketjen black (registered trademark, manufactured by Ketjen Black International Co., Ltd.). Examples of the carbon fiber include carbon nanotubes and carbon nanofibers, and examples of the carbon nanotube include VGCF (registered trademark, manufactured by Showa Denko Co., Ltd.), which is a vapor phase carbon fiber.
〔３－６．電極スラリーの性質〕
　電極スラリーの不揮発分濃度は、２０質量％以上であることが好ましく、３０質量％以上であることがより好ましく、４０質量％以上であることがさらに好ましい。電極スラリー中の有効成分の濃度が高くなり、少ない電極スラリーの量で、十分な量の電極活物質層を形成できるためである。電極スラリーの不揮発分濃度は、電極スラリー中の水性媒体の量で調整できる。 [3-6. Properties of electrode slurry]
The non-volatile content concentration of the electrode slurry is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more. This is because the concentration of the active ingredient in the electrode slurry becomes high, and a sufficient amount of the electrode active material layer can be formed with a small amount of the electrode slurry. The non-volatile content concentration of the electrode slurry can be adjusted by adjusting the amount of the aqueous medium in the electrode slurry.
　電極スラリーの不揮発分濃度は、８５質量％以下であることが好ましく、７５質量％以下であることがより好ましく、６５質量％以下であることがさらに好ましい。電極スラリーの塗工性を良好に保つためである。 The non-volatile content concentration of the electrode slurry is preferably 85% by mass or less, more preferably 75% by mass or less, and further preferably 65% by mass or less. This is to maintain good coatability of the electrode slurry.
　電極スラリーの粘度は、２００００ｍＰａ・ｓ以下であることが好ましく、１００００ｍＰａ・ｓ以下であることがより好ましく、５０００ｍＰａ・ｓ以下であることがさらに好ましい。電極スラリーの集電体への塗布性を向上させ、電極の生産性が向上するためである。電極スラリーの粘度は、電極スラリーの不揮発分濃度、及び増粘剤の種類及び量により大きく影響される。 The viscosity of the electrode slurry is preferably 20000 mPa · s or less, more preferably 10,000 mPa · s or less, and further preferably 5000 mPa · s or less. This is because the applicability of the electrode slurry to the current collector is improved and the productivity of the electrodes is improved. The viscosity of the electrode slurry is greatly affected by the non-volatile content concentration of the electrode slurry and the type and amount of the thickener.
　２３℃における電極スラリーのｐＨは、電極の仕様及び作製条件等によって適宜調整すればよく、限定はされないが、好ましくは２．０～１０であり、より好ましくは４．０～９．０であり、さらに好ましくは６．０～９．０である。電極スラリーを用いて作製される電池の耐久性を向上させるためである。 The pH of the electrode slurry at 23 ° C. may be appropriately adjusted depending on the specifications of the electrode, the production conditions, and the like, and is not limited, but is preferably 2.0 to 10, and more preferably 4.0 to 9.0. , More preferably 6.0 to 9.0. This is to improve the durability of the battery manufactured by using the electrode slurry.
〔３－７．電極スラリーの製造方法〕
　電極スラリーを調製する方法としては、バインダー組成物と、電極活物質と、必要に応じて増粘剤と、必要に応じて水性媒体と、必要に応じて導電助剤と、必要に応じてその他の成分とを混合する方法が挙げられるがこの方法に限られない。添加する成分の順序は、特に限定されず、適宜決めればよい。混合方法としては、攪拌式、回転式、振とう式等の混合装置を使用する方法が挙げられる。 [3-7. Method of manufacturing electrode slurry]
Methods for preparing the electrode slurry include a binder composition, an electrode active material, a thickener if necessary, an aqueous medium if necessary, a conductive auxiliary agent if necessary, and others if necessary. A method of mixing with the components of the above can be mentioned, but the method is not limited to this method. The order of the components to be added is not particularly limited and may be appropriately determined. Examples of the mixing method include a method using a mixing device such as a stirring type, a rotary type, and a shaking type.
＜４．非水系二次電池電極＞
　本実施形態にかかる非水系二次電池電極（以下、「電極」とすることもある）は、集電体と、集電体上に形成された電極活物質層と、を備える。電極の形状としては、例えば、積層体及び捲回体等が挙げられるが、特に限定されない。また、集電体上への電極活物質層の形成範囲は特に限定されず、集電体の全面に形成されていてもよく、集電体の一部の面に形成されていてもよい。集電体が板、箔等の形状である場合、電極活物質層は、集電体の両面に形成されていてもよく、片面のみに形成されていてもよい。 <4. Non-aqueous secondary battery electrode ＞
The non-aqueous secondary battery electrode (hereinafter, may be referred to as “electrode”) according to the present embodiment includes a current collector and an electrode active material layer formed on the current collector. Examples of the shape of the electrode include a laminated body and a wound body, but the shape is not particularly limited. Further, the range of forming the electrode active material layer on the current collector is not particularly limited, and it may be formed on the entire surface of the current collector or may be formed on a part of the surface of the current collector. When the current collector is in the shape of a plate, foil, or the like, the electrode active material layer may be formed on both sides of the current collector, or may be formed on only one side.
〔４－１．集電体〕
　集電体は、厚さ０．００１ｍｍ以上０．５ｍｍ以下の金属シートであることが好ましく、金属としては、鉄、銅、アルミニウム、ニッケル、ステンレス等が挙げられる。非水系二次電池電極が、リチウムイオン二次電池の負極である場合、集電体は、銅箔であることが好ましい。 [4-1. Current collector]
The current collector is preferably a metal sheet having a thickness of 0.001 mm or more and 0.5 mm or less, and examples of the metal include iron, copper, aluminum, nickel, and stainless steel. When the non-aqueous secondary battery electrode is the negative electrode of the lithium ion secondary battery, the current collector is preferably a copper foil.
〔４－２．電極活物質層〕
　本実施形態にかかる電極活物質層は、電極バインダー及び電極活物質を含む。電極活物質層は、導電助剤、増粘剤等を含んでもよい。ここで挙げた成分については上述したとおりである。 [4-2. Electrode active material layer]
The electrode active material layer according to the present embodiment includes an electrode binder and an electrode active material. The electrode active material layer may contain a conductive auxiliary agent, a thickener and the like. The components listed here are as described above.
〔４－３．電極の製造方法〕
　電極の製造方法としては、例えば、電極スラリーを集電体上に塗布し、乾燥させて電極活物質層を形成した後、適当な大きさに切断することにより製造できる。 [4-3. Electrode manufacturing method]
As a method for manufacturing an electrode, for example, an electrode slurry is applied onto a current collector, dried to form an electrode active material layer, and then cut into an appropriate size.
　電極スラリーを集電体上に塗布する方法としては、特に限定されないが、例えば、リバースロール法、ダイレクトロール法、ドクターブレード法、ナイフ法、エクストルージョン法、カーテン法、グラビア法、バー法、ディップ法、スクイーズ法等が挙げられる。これらの中でも、電極スラリーの粘性等の諸物性及び乾燥性を考慮すると、ドクターブレード法、ナイフ法、またはエクストルージョン法を用いることが好ましい。表面が滑らかで、厚さのばらつきが小さな電極活物質層を得ることができるためである。 The method of applying the electrode slurry onto the current collector is not particularly limited, but for example, the reverse roll method, the direct roll method, the doctor blade method, the knife method, the extrusion method, the curtain method, the gravure method, the bar method, and the dip method. Law, squeeze method, etc. can be mentioned. Among these, the doctor blade method, the knife method, or the extrusion method is preferably used in consideration of various physical properties such as the viscosity of the electrode slurry and the drying property. This is because it is possible to obtain an electrode active material layer having a smooth surface and a small variation in thickness.
　電極スラリーは、集電体の片面にのみ塗布してもよいし、両面に塗布してもよい。電極スラリーを集電体の両面に塗布する場合は、片面ずつ逐次塗布してもよいし、両面同時に塗布してもよい。また、電極スラリーは、集電体へ連続的に塗布してもよいし、間欠的に塗布してもよい。電極スラリーの塗布量は、電池の設計容量、及び電極スラリーの組成などに応じて適宜決定できる。電極スラリーの塗布量は、電極スラリーの性質にもよるが、１３ｍｇ／ｃｍ２以下（両面に塗布する場合、片面あたりの塗布量）であることが好ましい。電極スラリーの乾燥工程において電極表面の亀裂の発生を抑制できるためである。 The electrode slurry may be applied to only one side of the current collector or may be applied to both sides. When the electrode slurry is applied to both sides of the current collector, it may be applied sequentially on one side at a time or on both sides at the same time. Further, the electrode slurry may be continuously applied to the current collector or may be applied intermittently. The coating amount of the electrode slurry can be appropriately determined according to the design capacity of the battery, the composition of the electrode slurry, and the like. The coating amount of the electrode slurry depends on the properties of the electrode slurry, but is preferably 13 mg / cm 2 or less (when coated on both sides, the coating amount per one side). This is because the occurrence of cracks on the electrode surface can be suppressed in the process of drying the electrode slurry.
　集電体上に塗布された電極スラリーを乾燥することにより、集電体上に電極活物質層が形成される。電極スラリーの乾燥方法は、特に限定されないが、例えば、熱風、減圧あるいは真空環境、（遠）赤外線、低温風を単独あるいは組み合わせて用いることができる。電極スラリーの乾燥温度及び乾燥時間は、電極スラリー中の不揮発分濃度、集電体への塗布量等によって適宜調整することができる。乾燥温度は、４０℃以上３５０℃以下であることが好ましく、生産性の観点から、６０℃以上１００℃以下であることがより好ましい。乾燥時間は１分以上３０分以下であることが好ましい。 By drying the electrode slurry applied on the current collector, an electrode active material layer is formed on the current collector. The method for drying the electrode slurry is not particularly limited, and for example, hot air, reduced pressure or vacuum environment, (far) infrared rays, and low temperature air can be used alone or in combination. The drying temperature and drying time of the electrode slurry can be appropriately adjusted depending on the concentration of the non-volatile content in the electrode slurry, the amount of coating on the current collector, and the like. The drying temperature is preferably 40 ° C. or higher and 350 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower from the viewpoint of productivity. The drying time is preferably 1 minute or more and 30 minutes or less.
　集電体上に電極活物質層が形成された電極シートは、電極として適当な大きさ及び形状にするために切断されてもよい。電極シートの切断方法は特に限定されないが、例えば、スリット、レーザー、ワイヤーカット、カッター、トムソン等を用いることができる。 The electrode sheet on which the electrode active material layer is formed on the current collector may be cut in order to obtain an appropriate size and shape as an electrode. The method for cutting the electrode sheet is not particularly limited, but for example, a slit, a laser, a wire cut, a cutter, a Thomson, or the like can be used.
　電極シートを切断する前または後に、必要に応じて電極シートをプレスしてもよい。それによって電極活物質を集電体により強固に結着させ、さらに電極を薄くすることによる非水系電池の小型化が可能になる。プレスの方法としては、一般的な方法を用いることができ、特に金型プレス法またはロールプレス法を用いることが好ましい。金型プレス法の場合、プレス圧は、特に限定されないが、０．５ｔ／ｃｍ２以上５ｔ／ｃｍ２以下とすることが好ましい。ロールプレス法の場合、線圧は、特に限定されないが、０．５ｔ／ｃｍ以上５ｔ／ｃｍ以下とすることが好ましい。プレスによる上記効果を得つつ、電極活物質へのリチウムイオン等の電荷キャリアの挿入及び脱離容量の低下を抑制するためである。 The electrode sheet may be pressed as needed before or after cutting the electrode sheet. As a result, the electrode active material is firmly bound to the current collector, and the electrode can be made thinner, so that the non-aqueous battery can be miniaturized. As a pressing method, a general method can be used, and it is particularly preferable to use a die pressing method or a roll pressing method. In the case of the die pressing method, the pressing pressure is not particularly limited, but is preferably 0.5 t / cm 2 or more and 5 t / cm 2 or less. In the case of the roll press method, the linear pressure is not particularly limited, but is preferably 0.5 t / cm or more and 5 t / cm or less. This is to suppress the insertion of charge carriers such as lithium ions into the electrode active material and the decrease in the desorption capacity while obtaining the above effects by the press.
＜５．非水系二次電池＞
　本実施形態にかかる非水系二次電池の好ましい一例として、リチウムイオン二次電池について説明するが、電池の構成はここで説明したものに限られない。本実施形態にかかる非水系二次電池は、正極と、負極と、電解液と、必要に応じてセパレータ等の部品と、が外装体に収容されたものであり、正極及び負極のうちの一方または両方に上記の方法により作製された電極を用いる。本実施形態にかかる非水系二次電池において、正極及び負極の少なくとも一方が、本発明にかかる電極バインダーを含むが、少なくとも負極が本発明にかかる電極バインダーを含むことが好ましい。 <5. Non-water-based secondary battery ＞
A lithium ion secondary battery will be described as a preferred example of the non-aqueous secondary battery according to the present embodiment, but the battery configuration is not limited to that described here. The non-aqueous secondary battery according to the present embodiment has a positive electrode, a negative electrode, an electrolytic solution, and, if necessary, a component such as a separator, housed in an exterior body, and is one of a positive electrode and a negative electrode. Alternatively, the electrodes produced by the above method are used for both. In the non-aqueous secondary battery according to the present embodiment, at least one of the positive electrode and the negative electrode contains the electrode binder according to the present invention, but it is preferable that at least the negative electrode contains the electrode binder according to the present invention.
〔５－１．電解液〕
　電解液としては、イオン伝導性を有する非水系の液体を使用する。電解液としては、電解質を有機溶媒に溶解させた溶液、イオン液体等が挙げられるが、前者が好ましい。製造コストが低く、内部抵抗の低い非水系電池が得られるためである。 [5-1. Electrolyte]
As the electrolytic solution, a non-aqueous liquid having ionic conductivity is used. Examples of the electrolytic solution include a solution in which an electrolyte is dissolved in an organic solvent, an ionic liquid, and the like, and the former is preferable. This is because a non-aqueous battery having a low manufacturing cost and a low internal resistance can be obtained.
　電解質としては、アルカリ金属塩を用いることができ、電極活物質の種類等に応じ適宜選択できる。電解質としては、例えば、ＬｉＣｌＯ４、ＬｉＢＦ６、ＬｉＰＦ６、ＬｉＣＦ３ＳＯ３、ＬｉＣＦ３ＣＯ２、ＬｉＡｓＦ６、ＬｉＳｂＦ６、ＬｉＢ１０Ｃｌ１０、ＬｉＡｌＣｌ４、ＬｉＣｌ、ＬｉＢｒ、ＬｉＢ（Ｃ２Ｈ５）４、ＣＦ３ＳＯ３Ｌｉ、ＣＨ３ＳＯ３Ｌｉ、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＳＯ３、Ｌｉ（ＣＦ３ＳＯ２）２Ｎ、脂肪族カルボン酸リチウム等が挙げられる。また、電解質として、その他のアルカリ金属塩を用いることもできる。 As the electrolyte, an alkali metal salt can be used and can be appropriately selected depending on the type of the electrode active material and the like. Examples of the electrolyte include LiClO 4 , LiBF 6 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiB 10 Cl 10 , LiAlCl 4 , LiCl, LiBr, LiB (C2H 5 ). 4 , CF 3 SO 3 Li, CH 3 SO 3 Li, LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 N, lithium aliphatic carboxylate and the like can be mentioned. Further, other alkali metal salts can also be used as the electrolyte.
　電解質を溶解する有機溶媒としては、特に限定されないが、例えば、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ジエチルカーボネート（ＤＥＣ）、メチルエチルカーボネート（ＭＥＣ）、ジメチルカーボネート（ＤＭＣ）、フルオロエチレンカーボネート（ＦＥＣ）、ビニレンカーボネート（ＶＣ）等の炭酸エステル化合物；アセトニトリル等のニトリル化合物
酢酸エチル、酢酸プロピル、プロピオン酸メチル、プロピオン酸エチル、プロピオン酸プロピルなどのカルボン酸エステルが挙げられる。これらの有機溶媒は、１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。中でも、直鎖カーボネート系溶媒を組合せたものを用いることが好ましい。直鎖カーボネート系溶媒としては炭酸ジエチル、炭酸ジメチル、炭酸エチルメチルが挙げられる。 The organic solvent that dissolves the electrolyte is not particularly limited, and is, for example, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), dimethyl carbonate (DMC), and fluoroethylene carbonate. (FEC), carbonic acid ester compounds such as vinylene carbonate (VC); nitrile compounds such as acetonitrile Ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate and other carboxylic acid esters can be mentioned. These organic solvents may be used alone or in combination of two or more. Above all, it is preferable to use a combination of a linear carbonate solvent. Examples of the linear carbonate-based solvent include diethyl carbonate, dimethyl carbonate, and ethylmethyl carbonate.
〔５－２．外装体〕
　外装体としては、例えばアルミニウム箔と樹脂フィルムとのラミネート材などを適宜使用できるが、これに限られない。電池の形状は、コイン型、ボタン型、シート型、円筒型、角型、扁平型等、いずれの形状であってもよい。 [5-2. Exterior]
As the exterior body, for example, a laminated material of an aluminum foil and a resin film can be appropriately used, but the exterior body is not limited to this. The shape of the battery may be any shape such as a coin type, a button type, a sheet type, a cylindrical type, a square type, and a flat type.
　以下の実施例では、本発明の構成の一例としてリチウムイオン二次電池の負極、及びリチウムイオン二次電池を作製し、比較例にかかるリチウムイオン二次電池の負極、及びリチウムイオン二次電池と比較して、本発明の効果を確認する。なお、本発明はこれらによっては限定されない。なお、以下の実施例及び比較例で用いられる水は、特に断りがなければ、イオン交換水である。 In the following examples, as an example of the configuration of the present invention, a negative electrode of a lithium ion secondary battery and a lithium ion secondary battery are manufactured, and the negative electrode of the lithium ion secondary battery and the lithium ion secondary battery according to the comparative example are used. By comparison, the effect of the present invention is confirmed. The present invention is not limited thereto. Unless otherwise specified, the water used in the following Examples and Comparative Examples is ion-exchanged water.
＜１．共重合体（Ａ）または共重合体（ＣＡ）の水分散液＞
〔１－１．共重合体（Ａ）または共重合体（ＣＡ）の水分散液の作製〕
　表１及び表２に示す組成（質量部）の単量体（ａ）をラジカル重合し、共重合体（Ａ－１）～（Ａ－９）及び共重合体（ＣＡ－１）～（ＣＡ－３）それぞれの水分散液を得た。ここで、共重合体（Ａ－１）～（Ａ－９）を区別せずに述べる場合は共重合体（Ａ）、共重合体（ＣＡ－１）～（ＣＡ－３）を区別せずに述べる場合は共重合体（ＣＡ）とする。水分散液中の共重合体（Ａ）または共重合体（ＣＡ）の含有率は４０質量％となるようにした。重合に際しては、界面活性剤として、ポリオキシエチレンアルキルエーテル硫酸エステル塩（第一工業製薬株式会社製、ハイテノール０８Ｅ）を用いている。生成した水分散液において、上記界面活性剤は、共重合体（Ａ）または共重合体（ＣＡ）１００質量部に対して、０．２０質量部含んでいる。 <1. Water dispersion of copolymer (A) or copolymer (CA)>
[1-1. Preparation of water dispersion of copolymer (A) or copolymer (CA)]
The monomer (a) having the composition (part by mass) shown in Tables 1 and 2 is radically polymerized to carry out the copolymers (A-1) to (A-9) and the copolymers (CA-1) to (CA-1) to (CA). -3) Each aqueous dispersion was obtained. Here, when the copolymers (A-1) to (A-9) are described without distinction, the copolymer (A) and the copolymers (CA-1) to (CA-3) are not distinguished. In the case of the above, it is a copolymer (CA). The content of the copolymer (A) or the copolymer (CA) in the aqueous dispersion was adjusted to 40% by mass. In the polymerization, a polyoxyethylene alkyl ether sulfate ester salt (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., High Tenor 08E) is used as a surfactant. In the generated aqueous dispersion, the surfactant is contained in an amount of 0.20 parts by mass with respect to 100 parts by mass of the copolymer (A) or the copolymer (CA).
〔１－２．評価１：共重合体（Ａ）及び共重合体（ＣＡ）のガラス転移点の測定〕
　共重合体（Ａ）及び共重合体（ＣＡ）のガラス転移点の測定について説明する。得られた共重合体（Ａ）及び共重合体（ＣＡ）の水分散液をポリエチレンシート上に流延し、５０℃、５時間乾燥させたのち、５０℃で１時間９８ｋＰａ条件下で真空乾燥させて厚さ０．５ｍｍのフィルムを得た。 [1-2. Evaluation 1: Measurement of the glass transition point of the copolymer (A) and the copolymer (CA)]
The measurement of the glass transition point of the copolymer (A) and the copolymer (CA) will be described. The obtained aqueous dispersions of the copolymer (A) and the copolymer (CA) were cast on a polyethylene sheet, dried at 50 ° C. for 5 hours, and then vacuum dried at 50 ° C. for 1 hour under 98 kPa conditions. A film having a thickness of 0.5 mm was obtained.
　得られたフィルムを２ｍｍ×２ｍｍにカットし、アルミパンに密封して日立ハイテクサイエンス社製　ＥＸＳＴＡＲ　ＤＳＣ／ＳＳ７０２０を用いて昇温速度１０℃／分、窒素ガス雰囲気下でＤＳＣ測定を行った。ＤＳＣの温度微分として得られるＤＤＳＣチャートのピークトップ温度を測定し、この温度を共重合体（Ｐ）及び共重合体（ＣＰ）のガラス転移点Ｔｇ（℃）とした。測定温度範囲は－４０℃～２００℃とした。測定されたガラス転移点の値を表１に示す。 The obtained film was cut into 2 mm × 2 mm, sealed in an aluminum pan, and DSC measurement was performed using EXSTAR DSC / SS7020 manufactured by Hitachi High-Tech Science Co., Ltd. at a heating rate of 10 ° C./min in a nitrogen gas atmosphere. The peak top temperature of the DDSC chart obtained as the temperature differential of DSC was measured, and this temperature was defined as the glass transition point Tg (° C.) of the copolymer (P) and the copolymer (CP). The measurement temperature range was −40 ° C. to 200 ° C. The measured glass transition point values are shown in Table 1.
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000018
Figure JPOXMLDOC01-appb-T000019
Figure JPOXMLDOC01-appb-T000019
＜２．共重合体（Ｂ）の水溶液または水分散液の作製＞
　下に示す構造単位（１０）からなるブロックと、構造単位（１１）からなるブロックと、構造単位（１２）からなるブロックがこの順で配列された３元ブロック共重合体を４０質量％含む水分散液及び水溶液を、３種類作製した。これらの水分散液及び水溶液は、３元ブロック共重合体に含まれる各構造単位の含有率が異なっている。これら３種類の共重合体（Ｂ－１）～（Ｂ－３）の構成は表３に示すとおりである。 <2. Preparation of aqueous solution or aqueous dispersion of copolymer (B)>
Water containing 40% by mass of a ternary block copolymer in which a block composed of the structural unit (10), a block composed of the structural unit (11), and a block composed of the structural unit (12) are arranged in this order as shown below. Three types of dispersions and aqueous solutions were prepared. These aqueous dispersions and aqueous solutions have different contents of each structural unit contained in the ternary block copolymer. The configurations of these three types of copolymers (B-1) to (B-3) are as shown in Table 3.
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-T000020
Figure JPOXMLDOC01-appb-C000021
Figure JPOXMLDOC01-appb-C000021
Figure JPOXMLDOC01-appb-C000022
Figure JPOXMLDOC01-appb-C000022
Figure JPOXMLDOC01-appb-C000023
Figure JPOXMLDOC01-appb-C000023
＜３．バインダー組成物＞
〔３－１．バインダー組成物の調製〕
　共重合体（Ａ）または共重合体（ＣＡ）の分散液と、共重合体（Ｂ）の分散液または水溶液と、を混合した。各実施例及び比較例におけるこれらの混合量は、共重合体（Ａ）または共重合体（ＣＡ）と、共重合体（Ｂ）との割合が表４及び表５（条件の違いを比較しやすいように実施例１については表４及び表５のいずれにも記載した）に示される質量割合となるようにした。 <3. Binder composition>
[3-1. Preparation of binder composition]
The dispersion liquid of the copolymer (A) or the copolymer (CA) and the dispersion liquid or the aqueous solution of the copolymer (B) were mixed. In each of the examples and comparative examples, the ratios of the copolymer (A) or the copolymer (CA) and the copolymer (B) are shown in Tables 4 and 5 (comparing the differences in conditions). For ease of use, the mass ratio of Example 1 was set to the mass ratio shown in both Table 4 and Table 5).
Figure JPOXMLDOC01-appb-T000024
Figure JPOXMLDOC01-appb-T000024
Figure JPOXMLDOC01-appb-T000025
Figure JPOXMLDOC01-appb-T000025
　実施例及び比較例で得られたバインダー組成物の不揮発分濃度（質量％）を、以下の方法で測定した。測定結果を表４及び表５に示す。 The non-volatile content concentration (mass%) of the binder compositions obtained in Examples and Comparative Examples was measured by the following method. The measurement results are shown in Tables 4 and 5.
〔３－２．評価２：バインダー組成物の不揮発分濃度〕
　直径５ｃｍのアルミ皿にバインダー組成物を１ｇ秤量し、１気圧（１０１３ｈＰａ）で、乾燥器内で空気を循環させながら１０５℃で１時間乾燥させ、後に残った成分の質量を測定した。乾燥前のバインダー組成物の質量（１ｇ）に対する、乾燥後に残った上記成分の質量割合（質量％）を不揮発分濃度として算出した。 [3-2. Evaluation 2: Non-volatile content concentration of binder composition]
1 g of the binder composition was weighed on an aluminum dish having a diameter of 5 cm, dried at 1 atm (1013 hPa) at 105 ° C. for 1 hour while circulating air in a dryer, and the mass of the remaining components was measured. The mass ratio (mass%) of the above-mentioned components remaining after drying with respect to the mass (1 g) of the binder composition before drying was calculated as the non-volatile content concentration.
＜４．電極及び電池性能の評価＞
　各実施例及び比較例で作製したバインダー組成物を用いて、負極及びリチウムイオン二次電池を作製して、評価を行った。 <4. Evaluation of electrode and battery performance>
Using the binder compositions prepared in each Example and Comparative Example, a negative electrode and a lithium ion secondary battery were prepared and evaluated.
〔４－１．電池の作製〕
［４－１－１．正極の作製］
　正極活物質としてＬｉＮｉ０．６Ｍｎ０．２Ｃｏ０．２Ｏ２を９４質量部、導電助剤としてアセチレンブラックを３質量部、バインダーとしてポリフッ化ビニリデン３質量部を混合したものに、Ｎ－メチルピロリドンを５０質量部加えてさらに混合して正極スラリーを作製した。 [4-1. Battery production]
[4-1-1. Fabrication of positive electrode]
N - N- _ 50 parts by mass of methylpyrrolidone was added and further mixed to prepare a positive electrode slurry.
　厚さ１５μｍのアルミニウム箔（正極集電体）の両面に、正極スラリーを、ダイレクトロール法により塗布した。正極集電体への正極スラリーの塗布量は、後述するロールプレス処理後の厚さが片面当たり１２５μｍになるように調整した。 The positive electrode slurry was applied to both sides of an aluminum foil (positive electrode current collector) having a thickness of 15 μm by the direct roll method. The amount of the positive electrode slurry applied to the positive electrode current collector was adjusted so that the thickness after the roll press treatment described later was 125 μm per side.
　正極集電体上に塗布された正極スラリーを、１２０℃で５分乾燥し、ロールプレスにより（サンクメタル社製、プレス荷重５ｔ、ロール幅７ｃｍ）でプレスし、正極活物質層が形成された正極シートを得た。得られた正極シートを５０ｍｍ×４０ｍｍに切り出し、導電タブをつけて正極を作製した。 The positive electrode slurry applied on the positive electrode current collector was dried at 120 ° C. for 5 minutes and pressed by a roll press (manufactured by Thunk Metal Co., Ltd., press load 5 tons, roll width 7 cm) to form a positive electrode active material layer. A positive electrode sheet was obtained. The obtained positive electrode sheet was cut out to a size of 50 mm × 40 mm, and a conductive tab was attached to prepare a positive electrode.
［４－１－２．負極の作製］
　負極活物質として人造黒鉛（Ｇ４９、江西紫宸科技有限公司製）を１００質量部、各実施例及び比較例で作製したバインダー組成物を３．９質量部（不揮発分として１．５質量部）、及びＣＭＣ（カルボキシメチルセルロース－ナトリウム塩・日本製紙ケミカル株式会社製サンローズ（登録商標）ＭＡＣ５００ＬＣ）の２質量％水溶液を６２質量部混合し、さらに水を２８質量部添加して、負極スラリーを得た。 [4-1-2. Fabrication of negative electrode]
100 parts by mass of artificial graphite (G49, manufactured by Esai Shiho Technology Co., Ltd.) as a negative electrode active material, and 3.9 parts by mass of the binder composition prepared in each Example and Comparative Example (1.5 parts by mass as a non-volatile content). , And CMC (Carboxymethyl Cellulose-Sodium Salt, Sunrose (Registered Trademark) MAC500LC manufactured by Nippon Paper Chemical Co., Ltd.) are mixed in an amount of 62 parts by mass, and 28 parts by mass of water is further added to obtain a negative electrode slurry. rice field.
　厚さ１０μｍの銅箔（負極集電体）の両面に、負極スラリーを、ダイレクトロール法により塗布した。負極集電体への負極スラリーの塗布量は、後述するロールプレス処理後の厚さが片面当たり１７０μｍになるように調整した。 Negative electrode slurry was applied to both sides of a copper foil (negative electrode current collector) having a thickness of 10 μm by the direct roll method. The amount of the negative electrode slurry applied to the negative electrode current collector was adjusted so that the thickness after the roll press treatment described later was 170 μm per side.
　負極集電体上に塗布された負極スラリーを、９０℃で１０分乾燥させ、ロールプレスにより（サンクメタル社製、プレス荷重８ｔ、ロール幅７ｃｍ）プレスし、集電体上に負極活物質層が形成された負極シートを得た。得られた負極シートを５２ｍｍ×４２ｍｍに切り出し、導電タブをつけて負極を作製した。 The negative electrode slurry applied on the negative electrode current collector is dried at 90 ° C. for 10 minutes, pressed by a roll press (manufactured by Thunk Metal, press load 8 t, roll width 7 cm), and the negative electrode active material layer is placed on the current collector. Was formed to obtain a negative electrode sheet. The obtained negative electrode sheet was cut out to a size of 52 mm × 42 mm, and a conductive tab was attached to prepare a negative electrode.
［４－１－３．電池の作製］
　正極と負極との間にポリオレフィン系の多孔性フィルムからなるセパレータ（ポリエチレン製、２５μｍ）を介在させて、正極活物質層と負極活物質層とが互いに対向するようにアルミラミネート外装体（電池パック）の中に収納した。この外装体中に電解液を注液し真空含浸を行い、真空ヒートシーラーでパッキングし、評価用のリチウムイオン二次電池を作製した。電解液は、エチレンカーボネート（ＥＣ）／エチルメチルカーボネート（ＥＭＣ）／ジエチルカーボネート（ＤＥＣ）＝３０／５０／２０（体積比）の混合溶媒にＬｉＰＦ６を１．０ｍｏｌ／Ｌで溶解させた溶液９９質量部に、ビニレンカーボネート１質量部を混合して作製した。 [4-1-3. Battery production]
An aluminum-laminated exterior body (battery pack) with a separator (made of polyethylene, 25 μm) made of a polyolefin-based porous film interposed between the positive electrode and the negative electrode so that the positive electrode active material layer and the negative electrode active material layer face each other. ). An electrolytic solution was injected into the exterior body, vacuum impregnated, and packed with a vacuum heat sealer to prepare a lithium ion secondary battery for evaluation. The electrolytic solution is a solution 99 in which LiPF 6 is dissolved at 1.0 mol / L in a mixed solvent of ethylene carbonate (EC) / ethylmethyl carbonate (EMC) / diethyl carbonate (DEC) = 30/50/20 (volume ratio). It was prepared by mixing 1 part by mass of vinylene carbonate with 1 part by mass.
〔４－２．電極及び電池の評価〕
［４－２－１．評価３：負極活物質層の剥離強度（電極性能）］
　負極活物質層の集電体に対する剥離強度を以下のように測定した。上記の負極作製工程におけるプレス後の負極シートを２５ｍｍ×１００ｍｍのサイズにカットし、試験片とした。試験片上の負極活物質層と、幅５０ｍｍ、長さ２００ｍｍＳＵＳ板とを両面テープ（ＮＩＴＴＯＴＡＰＥ（登録商標）　Ｎｏ．５、日東電工（株）製）を用いて、試験片の中心とＳＵＳ板の中心とが一致するように貼り合わせた。なお、両面テープは試験片の全範囲をカバーするように貼り合わせた。 [4-2. Evaluation of electrodes and batteries]
[4-2-1. Evaluation 3: Peeling strength of negative electrode active material layer (electrode performance)]
The peel strength of the negative electrode active material layer with respect to the current collector was measured as follows. The negative electrode sheet after pressing in the above negative electrode manufacturing step was cut into a size of 25 mm × 100 mm and used as a test piece. Using double-sided tape (NITTO TAPE (registered trademark) No. 5, manufactured by Nitto Denko KK) with the negative electrode active material layer on the test piece and a SUS plate with a width of 50 mm and a length of 200 mm, the center of the test piece and the center of the SUS plate. It was pasted so that it matches. The double-sided tape was attached so as to cover the entire range of the test piece.
　試験片とＳＵＳ板とを貼り合わせた状態で１０分放置した後、ＳＵＳ板と貼り合わせられている負極活物質層を、試験片の一端から長さ方向に２０ｍｍ剥がし、銅箔側の試験片を１８０°折り返し、この部分（負極活物質層を剥がした試験片の部分の銅箔側）を試験機の上側のチャックで掴んだ。さらに、負極活物質層を剥がされた方のＳＵＳ板の一端を下側チャックで掴んだ。その状態で、試験片から銅箔を１００±１０ｍｍ／ｍｉｎの速度で引き剥がし、剥離長さ（ｍｍ）－剥離力（ｍＮ）のグラフを得た。得られたグラフにおいて剥離長さ１０～４５ｍｍにおける剥離力の平均値（ｍＮ）を算出し、剥離力の平均値を試験片の幅２５ｍｍで割った数値を負極活物質層の剥離強度（ｍＮ／ｍｍ）とした。なお、いずれの実施例及び比較例においても、試験中、両面テープとＳＵＳ板の間での剥離、及び両面テープと負極活物質層との間での界面剥離は起こらなかった。 After leaving the test piece and the SUS plate bonded together for 10 minutes, the negative electrode active material layer bonded to the SUS plate is peeled off by 20 mm in the length direction from one end of the test piece, and the test piece on the copper foil side is peeled off. Was folded back 180 °, and this portion (the copper foil side of the portion of the test piece from which the negative electrode active material layer was peeled off) was grasped by the chuck on the upper side of the testing machine. Further, one end of the SUS plate from which the negative electrode active material layer was peeled off was grasped by the lower chuck. In that state, the copper foil was peeled off from the test piece at a speed of 100 ± 10 mm / min, and a graph of peeling length (mm) -peeling force (mN) was obtained. In the obtained graph, the average value (mN) of the peeling force at the peeling length of 10 to 45 mm was calculated, and the value obtained by dividing the average value of the peeling force by the width of the test piece of 25 mm was the peeling strength (mN / mN /) of the negative electrode active material layer. mm). In each of the Examples and Comparative Examples, peeling between the double-sided tape and the SUS plate and interfacial peeling between the double-sided tape and the negative electrode active material layer did not occur during the test.
［４－２－２．評価４：電池の内部抵抗（ＤＣＲ）］
　電池の内部抵抗（ＤＣＲ（Ω））の測定は、２５℃の条件下、以下の手順で行った。レストポテンシャルから３．６Ｖまで０．２Ｃの定電流充電し、充電状態を初期容量の５０％（ＳＯＣ５０％）にした。その後、０．２Ｃ、０．５Ｃ、１Ｃおよび２Ｃの各電流値で６０秒間放電を行った。これらの４種の電流値（１秒間での値）と電圧の関係からＳＯＣ５０％でのＤＣＲ（Ω）を決定した。 [4-2-2. Evaluation 4: Battery internal resistance (DCR)]
The internal resistance (DCR (Ω)) of the battery was measured under the condition of 25 ° C. by the following procedure. A constant current charge of 0.2 C was performed from the rest potential to 3.6 V, and the charged state was set to 50% of the initial capacity (SOC 50%). Then, discharge was performed for 60 seconds at each current value of 0.2C, 0.5C, 1C and 2C. The DCR (Ω) at 50% SOC was determined from the relationship between these four types of current values (values per second) and voltage.
［４－２－３．評価５：高温下でのサイクル容量維持率（電池性能）］
　電池の、高温下でのサイクル容量維持率は、４５℃の条件下、以下の工程（ｉ）～（ｉｖ）の順で繰り返し行った。ここで、（ｉ）～（ｉｖ）の一連の操作１回分を１サイクルとする。 [4-2-3. Evaluation 5: Cycle capacity retention rate at high temperature (battery performance)]
The cycle capacity retention rate of the battery under high temperature was repeated in the following steps (i) to (iv) under the condition of 45 ° C. Here, one cycle of a series of operations (i) to (iv) is defined as one cycle.
（ｉ）電圧４．２Ｖになるまで、電流１Ｃで充電する（定電流（ＣＣ）充電）。
（ｉｉ）電圧４．２Ｖで、電流０．０５Ｃになるまで充電する（定電圧（ＣＶ）充電）。（ｉｉｉ）３０分静置する。
（ｉｖ）電圧２．７５Ｖになるまで電流１Ｃで放電する（定電流（ＣＣ）放電）。 (I) Charge with a current of 1 C until the voltage reaches 4.2 V (constant current (CC) charge).
(Ii) Charge at a voltage of 4.2 V until the current reaches 0.05 C (constant voltage (CV) charge). (Iii) Let stand for 30 minutes.
(Iv) Discharge with a current of 1 C until the voltage reaches 2.75 V (constant current (CC) discharge).
　工程（ｉ）及び（ｉｉ）における、電流の時間積分値を充電容量、工程（ｉｖ）における、電流の時間積分値を放電容量とする。１サイクル目の放電容量、及び１００サイクル目の放電容量を測定した。１００×（１００サイクル目の放電容量）／（１サイクル目の放電容量）［％］を電池の高温下でのサイクル容量維持率として算出し、表１と表２に示した。 The time integral value of the current in the steps (i) and (ii) is the charge capacity, and the time integral value of the current in the step (iv) is the discharge capacity. The discharge capacity in the first cycle and the discharge capacity in the 100th cycle were measured. 100 × (discharge capacity in the 100th cycle) / (discharge capacity in the first cycle) [%] was calculated as the cycle capacity retention rate under high temperature of the battery, and is shown in Tables 1 and 2.
＜５．評価結果＞
　各実施例の評価結果を見ると、いずれの実施例にかかる電極も負極活物質層の剥離強度が高いことがわかる。電池の評価において、いずれの実施例にかかる電池も低い内部抵抗及び高い放電容量維持率（優れたサイクル特性）を有することがわかる。 <5. Evaluation result>
Looking at the evaluation results of each example, it can be seen that the electrode according to each example has a high peel strength of the negative electrode active material layer. In the evaluation of the batteries, it can be seen that the batteries according to any of the embodiments have low internal resistance and high discharge capacity retention rate (excellent cycle characteristics).
　比較例１では、共重合体（Ｂ）を含まないバインダー組成物を用いて電極及び電池を作製した。しかし、電池の内部抵抗を十分に低減できず、また、放電容量維持率も十分ではなかった。 In Comparative Example 1, an electrode and a battery were produced using a binder composition containing no copolymer (B). However, the internal resistance of the battery could not be sufficiently reduced, and the discharge capacity retention rate was not sufficient.
　比較例２では、共重合体（Ｂ）を過剰に含むバインダー組成物を用いて電極及び電池を作製した。しかし、電極における負極活物質層の剥離強度は低かった。また、電池の放電容量維持率も十分ではなかった。 In Comparative Example 2, an electrode and a battery were prepared using a binder composition containing an excess of the copolymer (B). However, the peel strength of the negative electrode active material layer in the electrode was low. In addition, the discharge capacity retention rate of the battery was not sufficient.
　比較例３では、第１２構造単位を有さない共重合体（ＣＡ－１）を用いてバインダー組成物を作製した。比較例４では、第１２構造単位を過剰に有する共重合体（ＣＡ－２）を用いてバインダー組成物を作製した。比較例５では、第１３構造単位を過剰に有する共重合体（ＣＡ－３）を用いてバインダー組成物を作製した。しかし、これらのバインダー組成物を用いて作製された電極における負極活物質層の剥離強度は低かった。また、電池の内部抵抗を十分に低減できず、また、放電容量維持率も十分ではなかった。 In Comparative Example 3, a binder composition was prepared using a copolymer (CA-1) having no twelfth structural unit. In Comparative Example 4, a binder composition was prepared using a copolymer (CA-2) having an excess of the twelfth structural unit. In Comparative Example 5, a binder composition was prepared using a copolymer (CA-3) having an excess of the thirteenth structural unit. However, the peel strength of the negative electrode active material layer in the electrode produced by using these binder compositions was low. In addition, the internal resistance of the battery could not be sufficiently reduced, and the discharge capacity retention rate was not sufficient.
　以上のことから、本発明にかかる非水系二次電池電極バインダーによれば、非水系二次電池において電極活物質層の集電体に対する剥離強度を効果的に向上させ、電池の内部抵抗の低減及びサイクル特性の向上に貢献できることがわかる。 From the above, according to the non-aqueous secondary battery electrode binder according to the present invention, the peel strength of the electrode active material layer with respect to the current collector is effectively improved in the non-aqueous secondary battery, and the internal resistance of the battery is reduced. And it can be seen that it can contribute to the improvement of cycle characteristics.

Claims (14)

  1. 　共重合体（Ａ）及び共重合体（Ｂ）を含む非水系二次電池電極バインダーであって、
    　前記共重合体（Ａ）は、エチレン性不飽和結合を有する化合物の重合体であり、
    　前記共重合体（Ａ）は、単量体（ａ１）に由来する第１１構造単位と、単量体（ａ２）に由来する第１２構造単位と、を有し；或いは、単量体（ａ１）に由来する第１１構造単位と、単量体（ａ２）に由来する第１２構造単位と、内部架橋剤（ａ３）に由来する第１３構造単位と、を有し、
    　前記単量体（ａ１）は、エチレン性不飽和結合を有し、ヒドロキシ基及びシアノ基のいずれも有さず、独立した複数のエチレン性不飽和結合を有しないノニオン性化合物であり、
    　前記単量体（ａ２）は、エチレン性不飽和結合及びアニオン性官能基を有し、独立した複数のエチレン性不飽和結合を有しない化合物であり、
    　前記内部架橋剤（ａ３）は、独立した複数のエチレン性不飽和結合を有し、前記単量体（ａ１）及び前記単量体（ａ２）を含む単量体のラジカル重合において架橋構造を形成可能な化合物であり、
    　前記共重合体（Ａ）において、前記第１１構造単位１００質量部に対する、前記第１２構造単位の含有量は１．０質量部以上３０質量部以下であり、
    　前記共重合体（Ａ）において、前記第１１構造単位１００質量部に対する、前記第１３構造単位の含有量は、０質量部以上２０質量部以下であり、
    　前記共重合体（Ｂ）は、下記式（１）で表される第２１構造単位を全構造単位中５．０モル％以上９８モル％以下、下記式（２）で表される第２２構造単位を全構造単位中０．３０モル％以上９０モル％以下、及び下記式（３）で表される第２３構造単位を全構造単位中０．３０モル％以上１０モル％以下有し、
    　前記共重合体（Ｂ）における、全構造単位中の、前記第２１構造単位、前記第２２構造単位、及び前記第２３構造単位の合計含有率は、９０質量％以上であり、
    　前記共重合体（Ａ）の含有量と、前記共重合体（Ｂ）の含有量との質量比は、５０．０／５０．０以上９９．０／１．０以下であることを特徴とする非水系二次電池電極バインダー。
    Figure JPOXMLDOC01-appb-C000001
    Figure JPOXMLDOC01-appb-C000002
     　（式（２）において、Ｒ１は、分岐を有してもよい炭素数１以上６以下のアルキル基である。）
    Figure JPOXMLDOC01-appb-C000003
     　（式（３）において、Ｒ２は、エチレン性不飽和結合を有する基である。）     A non-aqueous secondary battery electrode binder containing the copolymer (A) and the copolymer (B).
    The copolymer (A) is a polymer of a compound having an ethylenically unsaturated bond.
    The copolymer (A) has an eleventh structural unit derived from the monomer (a1) and a twelfth structural unit derived from the monomer (a2); or the monomer (a1). ), A twelfth structural unit derived from the monomer (a2), and a thirteenth structural unit derived from the internal cross-linking agent (a3).
    The monomer (a1) is a nonionic compound having an ethylenically unsaturated bond, having neither a hydroxy group nor a cyano group, and having a plurality of independent ethylenically unsaturated bonds.
    The monomer (a2) is a compound having an ethylenically unsaturated bond and an anionic functional group and not having a plurality of independent ethylenically unsaturated bonds.
    The internal cross-linking agent (a3) has a plurality of independent ethylenically unsaturated bonds and forms a cross-linked structure by radical polymerization of the monomer (a1) and the monomer containing the monomer (a2). It is a possible compound and
    In the copolymer (A), the content of the 12th structural unit with respect to 100 parts by mass of the 11th structural unit is 1.0 part by mass or more and 30 parts by mass or less.
    In the copolymer (A), the content of the 13th structural unit with respect to 100 parts by mass of the 11th structural unit is 0 parts by mass or more and 20 parts by mass or less.
    The copolymer (B) contains the 21st structural unit represented by the following formula (1) in an amount of 5.0 mol% or more and 98 mol% or less, and the 22nd structure represented by the following formula (2). The unit has 0.30 mol% or more and 90 mol% or less in all structural units, and the 23rd structural unit represented by the following formula (3) has 0.30 mol% or more and 10 mol% or less in all structural units.
    The total content of the 21st structural unit, the 22nd structural unit, and the 23rd structural unit in the total structural unit of the copolymer (B) is 90% by mass or more.
    The mass ratio of the content of the copolymer (A) to the content of the copolymer (B) is 50.0 / 50.0 or more and 99.0 / 1.0 or less. Non-aqueous secondary battery electrode binder.
    Figure JPOXMLDOC01-appb-C000001
    Figure JPOXMLDOC01-appb-C000002
     (In the formula (2), R 1 is an alkyl group having 1 or more and 6 or less carbon atoms which may have a branch.)
    Figure JPOXMLDOC01-appb-C000003
     (In formula (3), R 2 is a group having an ethylenically unsaturated bond.)
  2. 　前記共重合体（Ｂ）は、
    　　前記第２１構造単位を、５．０モル％以上５０モル％以下、
    　　前記第２２構造単位を、４０モル％以上９０モル％以下、
    　　前記第２３構造単位を、０．３０モル％以上１０モル％以下
    含む請求項１に記載の非水系二次電池電極バインダー。     The copolymer (B) is
    The 21st structural unit is 5.0 mol% or more and 50 mol% or less,
    The 22nd structural unit is 40 mol% or more and 90 mol% or less,
    The non-aqueous secondary battery electrode binder according to claim 1, which contains the 23rd structural unit in an amount of 0.30 mol% or more and 10 mol% or less.
  3. 　前記共重合体（Ｂ）は、
    　　前記第２１構造単位を、７０モル％以上９８モル％以下、
    　　前記第２２構造単位を、０．３０モル％以上２０モル％以下、
    　　前記第２３構造単位を、０．３０モル％以上１０モル％以下
    含む請求項１に記載の非水系二次電池電極バインダー。     The copolymer (B) is
    The 21st structural unit is 70 mol% or more and 98 mol% or less,
    The 22nd structural unit is 0.30 mol% or more and 20 mol% or less,
    The non-aqueous secondary battery electrode binder according to claim 1, which contains the 23rd structural unit in an amount of 0.30 mol% or more and 10 mol% or less.
  4. 　前記式（３）において、Ｒ２は、ビニルオキシ基、アリルオキシ基、（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、及び－ＯＣＨ２－ＣＨ２－ＣＨ２＝ＣＨ２からなる群より選ばれる少なくともいずれか１つを有する請求項１～３のいずれか一項に記載の非水系二次電池電極バインダー。 In the formula (3), R 2 is at least selected from the group consisting of a vinyloxy group, an allyloxy group, a (meth) acryloyl group, a (meth) acryloyloxy group, and -OCH 2 -CH 2 -CH 2 = CH 2 . The non-aqueous secondary battery electrode binder according to any one of claims 1 to 3, which has any one.
  5. 　前記式（３）において、Ｒ２は、下記式（４）で表される請求項１～４のいずれか一項に記載の非水系二次電池電極バインダー。
    Figure JPOXMLDOC01-appb-C000004
     （式（４）において、Ｒ２１は分岐を有してもよい炭素数１～５のアルキレン基であり、Ｒ２２は、ビニルオキシ基、アリルオキシ基、（メタ）アクリロイル基、及び（メタ）アクリロイルオキシ基からなる群より選ばれる１つの官能基である。）     In the above formula (3), R 2 is the non-aqueous secondary battery electrode binder according to any one of claims 1 to 4 represented by the following formula (4).
    Figure JPOXMLDOC01-appb-C000004
     (In the formula (4), R 21 is an alkylene group having 1 to 5 carbon atoms which may have a branch, and R 22 is a vinyloxy group, an allyloxy group, a (meth) acryloyl group, and a (meth) acryloyloxy. It is one functional group selected from the group consisting of groups.)
  6. 　前記共重合体（Ｂ）は、第２１構造単位からなる第１ブロック、第２２構造単位からなる第２ブロック、及び第２３構造単位からなる第３ブロックを有するブロック共重合体である請求項１～５のいずれか１項に記載の非水系二次電池電極バインダー。 The block copolymer (B) is a block copolymer having a first block composed of a 21st structural unit, a second block composed of a 22nd structural unit, and a third block composed of a 23rd structural unit. The non-aqueous secondary battery electrode binder according to any one of 5 to 5.
  7. 　前記単量体（ａ１）は、極性官能基を有さない請求項１～６のいずれか１項に記載の非水系二次電池電極バインダー。 The non-aqueous secondary battery electrode binder according to any one of claims 1 to 6, wherein the monomer (a1) does not have a polar functional group.
  8. 　前記単量体（ａ２）は、カルボキシ基、及びスルホ基のうち少なくともいずれかを有する化合物である請求項１～７のいずれか１項に記載の非水系二次電池電極バインダー。 The non-aqueous secondary battery electrode binder according to any one of claims 1 to 7, wherein the monomer (a2) is a compound having at least one of a carboxy group and a sulfo group.
  9. 　前記共重合体（Ａ）は、前記第１１構造単位及び前記第１２構造単位を合計で８０質量％以上含む請求項１～８のいずれか１項に記載の非水系二次電池電極バインダー。 The non-aqueous secondary battery electrode binder according to any one of claims 1 to 8, wherein the copolymer (A) contains 80% by mass or more of the 11th structural unit and the 12th structural unit in total.
  10. 　前記共重合体（Ａ）において、前記第１１構造単位１００質量部に対する、前記第１３構造単位の含有量は、０．０５０質量部以上である請求項１～９のいずれか１項に記載の非水系二次電池電極バインダー。 The invention according to any one of claims 1 to 9, wherein in the copolymer (A), the content of the 13th structural unit with respect to 100 parts by mass of the 11th structural unit is 0.050 parts by mass or more. Non-aqueous secondary battery electrode binder.
  11. 　請求項１～１０のいずれか１項に記載の非水系二次電池電極バインダーと、水性媒体と、を含む非水系二次電池電極バインダー組成物。 A non-aqueous secondary battery electrode binder composition comprising the non-aqueous secondary battery electrode binder according to any one of claims 1 to 10 and an aqueous medium.
  12. 　請求項１～１０のいずれか１項に記載の非水系二次電池電極バインダーと、電極活物質と、水性媒体と、を含み、
    　該水性媒体は、水、親水性の溶媒、及び水と親水性の溶媒とを含む混合物からなる群から選択される１つ媒体である非水系二次電池電極スラリー。     The non-aqueous secondary battery electrode binder according to any one of claims 1 to 10, the electrode active material, and an aqueous medium are included.
    The aqueous medium is a non-aqueous secondary battery electrode slurry which is one medium selected from the group consisting of water, a hydrophilic solvent, and a mixture containing water and a hydrophilic solvent.
  13. 　請求項１～１０のいずれか１項に記載の非水系二次電池電極バインダーを含む非水系二次電池電極。 A non-aqueous secondary battery electrode containing the non-aqueous secondary battery electrode binder according to any one of claims 1 to 10.
  14. 　請求項１３に記載の非水系二次電池電極を含む、非水系二次電池。 A non-aqueous secondary battery including the non-aqueous secondary battery electrode according to claim 13.
PCT/JP2021/046248 2020-12-24 2021-12-15 Non-aqueous secondary battery electrode binder, non-aqueous secondary battery electrode binder composition, and non-aqueous secondary battery WO2022138371A1 (en)

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