WO2011065460A1 - Polymer electrolyte, polymer electrolyte film, film-electrode assembly, and solid polymer fuel cell - Google Patents

Polymer electrolyte, polymer electrolyte film, film-electrode assembly, and solid polymer fuel cell Download PDF

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Publication number
WO2011065460A1
WO2011065460A1 PCT/JP2010/071088 JP2010071088W WO2011065460A1 WO 2011065460 A1 WO2011065460 A1 WO 2011065460A1 JP 2010071088 W JP2010071088 W JP 2010071088W WO 2011065460 A1 WO2011065460 A1 WO 2011065460A1
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Prior art keywords
polymer electrolyte
aromatic vinyl
polymer
block
polymer block
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PCT/JP2010/071088
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French (fr)
Japanese (ja)
Inventor
竹友 山下
友裕 小野
和哉 清水
敬次 久保
望 須郷
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株式会社クラレ
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Priority to JP2011543309A priority Critical patent/JP5629692B2/en
Publication of WO2011065460A1 publication Critical patent/WO2011065460A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
    • H01B1/12—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances organic substances
    • H01B1/122—Ionic conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018—Polymeric electrolyte materials
    • H01M8/102—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer
    • H01M8/1023—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0065—Solid electrolytes
    • H01M2300/0082—Organic polymers
    • 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
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a polymer electrolyte excellent in ion conductivity under low humidity and less swollen by water, a polymer electrolyte membrane composed of the polymer electrolyte, and a membrane-electrode junction using the polymer electrolyte membrane And a polymer electrolyte fuel cell.
  • PEFCs polymer electrolyte fuel cells
  • a polymer electrolyte fuel cell is generally configured as follows. On both sides of the polymer electrolyte membrane having proton conductivity, a catalyst layer containing carbon powder carrying a white metal catalyst and an ion conductive binder made of a polymer electrolyte is disposed. A gas diffusion layer, which is a porous material through which fuel gas and oxidant gas are passed, is disposed outside each catalyst layer. Carbon paper, carbon cloth, or the like is used as the gas diffusion layer.
  • a structure in which a catalyst layer and a gas diffusion layer are integrated is called a gas diffusion electrode, and a structure in which a pair of gas diffusion electrodes is bonded to a polymer electrolyte membrane so that the catalyst layer faces the polymer electrolyte membrane is a membrane- It is called an electrode assembly (MEA; Mebrane Electrode Assembly).
  • MEA Mebrane Electrode Assembly
  • separators On both sides of the membrane-electrode assembly, separators having conductivity and airtightness are disposed.
  • a gas flow path for supplying fuel gas or oxidant gas (for example, air) to the electrode surface is formed in the contact portion of the membrane-electrode assembly and the separator or in the separator.
  • Electric power is generated by supplying a fuel gas to one electrode (fuel electrode) and an oxidant gas (such as air) containing oxygen to the other electrode (oxygen electrode). That is, at the fuel electrode, the fuel is ionized to generate protons and electrons, the protons pass through the polymer electrolyte membrane, and the electrons move through an external electric circuit formed by connecting the two electrodes, and are respectively transferred to the oxygen electrode. Reach and react with the oxidant gas to produce water. In this way, the chemical energy of the fuel can be directly converted into electric energy and taken out.
  • oxidant gas such as air
  • polymer electrolyte fuel cells usually perform intermittent operation that repeats start-up, operation, and stop, instead of continuous operation, in general applications as described above.
  • the polymer electrolyte membrane is wet during operation, but the humidity of the membrane decreases when stopped. For this reason, a polymer electrolyte membrane having high proton conductivity even under low humidity is desired in order to quickly exhibit performance at start-up.
  • Nafion a registered trademark of Nafion, DuPont
  • Nafion is a perfluorocarbon sulfonic acid polymer, because it is chemically stable.
  • Nafion is excellent in ionic conductivity under low humidity, but there is a possibility that a fluorine-based compound that adversely affects the environment may be generated as a decomposition product during long-term use or disposal. Further, since it has drawbacks such as high fuel permeability and high cost, an alternative material has been demanded.
  • hydrocarbon-based materials have been proposed as alternatives to perfluorocarbon sulfonic acid-based polymers such as Nafion.
  • PES polyethersulfone
  • PEEK polyetheretherketone
  • Patent Document 1 proposes a sulfonated product of PES. Since such a material does not contain fluorine, no fluorine compound is generated even if the material is deteriorated.
  • the raw material polymer itself is advantageous in terms of price compared to the perfluorocarbon sulfonic acid polymer.
  • the ion conductive groups are uniformly dispersed in the molecule, so the density of the ion conductive groups is low and it is difficult to achieve high ion conductivity. is there.
  • a sulfonated product of a modified PES having a polymer block having an ion conductive group introduced therein and a polymer block having no ion conductive group introduced therein has also been proposed.
  • it is a condensation polymer, an exchange reaction of repeating units occurs at the time of synthesis and the block structure is destroyed, so that a phase separation structure cannot be obtained and sufficient ion channels cannot be formed.
  • the polymer electrolyte membrane described in Patent Document 3 is composed of a block polymer having an aromatic vinyl polymer block and an aliphatic vinyl polymer block, which does not cause the above-described repeating unit exchange reaction.
  • the structure is retained. Therefore, ion channels can be formed by the phase separation structure unique to the block polymer.
  • the polymer electrolyte membrane composed of a block polymer having an aromatic vinyl polymer block and an aliphatic vinyl polymer block has insufficient performance in a low humidity state. There was a limit. Therefore, the actual situation is that sufficient ion conductivity cannot be secured in a low humidity state.
  • the polymer electrolyte membrane is used in a solid polymer fuel cell, it is desired that the polymer electrolyte membrane is less swelled by water in contact with the polymer electrolyte membrane during power generation of the polymer electrolyte fuel cell.
  • the polymer electrolyte membrane is deformed by swelling, peeling of the polymer electrolyte membrane from the electrode tends to occur in the membrane-electrode assembly.
  • a significant change in the shape of the polymer electrolyte membrane, and hence breakdown may occur, which may adversely affect long-term durability.
  • a block copolymer comprising at least an aromatic vinyl polymer block (A) and an aliphatic vinyl polymer block (B) as constituent components.
  • the aromatic vinyl polymer block (A) has an ion conductive group content per repeating unit of 1.5 to 3.0, and the aliphatic vinyl polymer block (B) has found that the above-mentioned problems can be solved by providing a polymer electrolyte characterized by not having an ion conductive group.
  • a polymer electrolyte comprising a block copolymer having at least an aromatic vinyl polymer block (A) and an aliphatic vinyl polymer block (B) as constituent components, wherein the aromatic vinyl polymer block ( The ion conductive group content per repeating unit in A) is 1.5 to 3.0, and the aliphatic vinyl polymer block (B) does not have an ion conductive group.
  • the present invention relates to a polymer electrolyte.
  • the invention according to claim 2 2.
  • the invention according to claim 3 2.
  • the aliphatic vinyl polymer block (B) is an alkene unit having 2 to 8 carbon atoms, a cycloalkene unit having 5 to 8 carbon atoms, a vinyl cycloalkane unit having 7 to 10 carbon atoms, or a vinyl having 7 to 10 carbon atoms. It is a rubbery polymer block containing as a main component at least one repeating unit selected from the group consisting of a cycloalkene unit, a conjugated diene unit having 4 to 8 carbon atoms, and a conjugated cycloalkadiene unit having 5 to 8 carbon atoms.
  • the invention according to claim 5 The polymer electrolyte according to claim 1, wherein the ion conductive group is a proton conductive group.
  • the invention according to claim 6 The aromatic vinyl polymer block (C) mainly comprising an aromatic vinyl compound unit having no ion conductive group as a repeating unit is contained as a constituent component in an amount of 20 to 60% by weight.
  • the present invention relates to a polymer electrolyte.
  • the invention according to claim 7 provides The aromatic vinyl compound unit, which is the main repeating unit of the aromatic vinyl polymer block (C), is a substituted aromatic vinyl compound having 1 to 3 C 1-8 hydrocarbon groups on the aromatic ring. It is a compound unit, It is related with the polymer electrolyte of Claim 6.
  • the invention according to claim 8 provides The present invention relates to a polymer electrolyte membrane comprising the polymer electrolyte according to claim 1.
  • the invention described in claim 9 The present invention relates to a membrane-electrode assembly having a multilayer structure of at least the polymer electrolyte membrane according to claim 8 and an electrode layer.
  • the invention according to claim 10 provides A solid polymer fuel cell comprising the membrane-electrode assembly according to claim 9.
  • the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) undergo microphase separation, and the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) have the property of gathering together, and since the aromatic vinyl polymer block (A) has an ion conductive group, the aromatic vinyl polymer block (A) An ion channel is formed by the aggregation of each other, and becomes a path for ions such as protons.
  • microphase separation means phase separation in a microscopic sense, and more specifically, means phase separation in which the formed domain size is less than or equal to the wavelength of visible light (3800 to 7800 mm). Shall.
  • the aromatic vinyl polymer block (A) has an ion conductive group content of 1.5 to 3.0 per repeating unit, and the aliphatic vinyl polymer block (B) has an ion conductivity.
  • the ion channel is dense and ion-conducting groups are present.
  • the polymer electrolyte membrane comprising the polymer electrolyte of the present invention
  • phase separation occurs remarkably and ion conductivity becomes high, and particularly has high ion conductivity under low humidity.
  • the membrane-electrode assembly comprising the polymer electrolyte fuel cell, it is possible to obtain high output characteristics even under a low humidity, and there is little swelling due to water, and the bonding property to the electrode is also improved. Excellent.
  • the block copolymer constituting the polymer electrolyte of the present invention contains an aromatic vinyl polymer block (A) as a constituent component.
  • the aromatic vinyl polymer block (A) has an aromatic vinyl compound unit as a main repeating unit and an ion conductive group content per repeating unit of 1.5 to 3.0. It is appropriately selected depending on the required performance of the molecular electrolyte. From the viewpoint of ion conductivity, it is preferably 1.7 or more, and from the viewpoint of ease of introduction of the sulfonic acid group, it is preferably 1.5 to 2.0.
  • the aromatic vinyl compound unit that is a repeating unit of the aromatic vinyl polymer block (A) is a structure that can be formed by polymerization of an aromatic vinyl compound.
  • the aromatic vinyl compound refers to a compound having at least one functional group containing at least one aromatic ring and an addition polymerizable carbon double bond directly bonded to a carbon atom on at least one aromatic ring.
  • Examples thereof include compounds in which hydrogen on an aromatic ring such as a benzene ring is substituted with a substituent such as a vinyl group, a 1-alkylethenyl group (eg, an isopropenyl group), or a 1-arylethenyl group.
  • a substituent such as a vinyl group, a 1-alkylethenyl group (eg, an isopropenyl group), or a 1-arylethenyl group.
  • Specific examples include styrene, ⁇ -methylstyrene, and diphenylethylene.
  • the aromatic vinyl compound that can form an aromatic vinyl compound unit that is a repeating unit of the aromatic vinyl polymer block (A) preferably has 10 or more carbon atoms that form an aromatic ring.
  • a compound having a plurality of aromatic rings having 10 or less carbon atoms such as a benzene ring and a compound having a condensed ring obtained by condensing the aromatic rings having 10 or less carbon atoms can be given.
  • aromatic vinyl compound having a plurality of benzene rings examples include vinyl biphenyl, vinyl terphenyl, phenoxystyrene, and diphenylethylene.
  • examples of the condensed ring include a naphthalene ring, a phenanthrene ring, an anthracene ring, a pyrene ring, a chrysene ring, and a fluorene ring.
  • aromatic vinyl compounds include vinyl naphthalene, vinyl phenanthrene, vinyl anthracene, vinyl pyrene, and vinyl chrysene vinyl fluorene.
  • vinyl naphthalene, vinyl biphenyl, and vinyl terphenyl are preferred because the molecular weight of the repeating unit is small and the structure is compact, which is advantageous for increasing the density of the ion channel.
  • Vinyl biphenyl is even more preferred.
  • the average molecular weight of the aromatic vinyl compound unit is preferably 400 or less, preferably 300 or less, and more preferably 200 or less.
  • the average molecular weight is a polymer block obtained by substituting all ion conductive groups of the aromatic vinyl polymer block with hydrogen (that is, the corresponding ion conductivity). It is calculated assuming a polymer block having no group. If the average molecular weight of the repeating unit is too large, the density of the ion channel may decrease, which is not preferable.
  • aromatic vinyl compound When the aromatic vinyl compound is polymerized into the aromatic vinyl polymer block (A), two or more aromatic vinyl compounds may be used in combination.
  • the form in the case of copolymerizing two or more of these may be random copolymerization, block copolymerization, graft copolymerization or tapered copolymerization.
  • the aromatic vinyl polymer block (A) may contain one or more other monomer units as long as the effects of the invention are not impaired.
  • monomers that can constitute such other monomer units include conjugated dienes having 4 to 8 carbon atoms (1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 2,4 -Hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-heptadiene, 1,4-heptadiene, 3,5-heptadiene, etc.), carbon number 2-8 Alkenes (ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-heptene, 2-heptene, 1-octene, 2-octene, etc.) , (Meth) acrylate esters (methyl (methylene
  • the aromatic vinyl polymer block (A) occupies 5 to 50% by weight of the polymer electrolyte in order for the polymer electrolyte membrane to satisfy both ion conductivity and water resistance. From the viewpoint of ionic conductivity, it is more preferable to occupy 35 to 50% by weight, and from the viewpoint of water resistance, it is more preferable to occupy 5 to 25% by weight. To achieve both ionic conductivity and water resistance, 20% is preferable. More preferably, it accounts for ⁇ 40% by weight.
  • the aromatic vinyl polymer block (A) is advantageous in causing microphase separation from the aliphatic vinyl polymer block (B) by using the aromatic vinyl compound block as a main repeating unit.
  • That the aromatic vinyl compound unit is the main repeating unit means that the aromatic vinyl polymer block (A) accounts for more than 80% by weight, and in order to impart sufficient ion conductivity, 90% It is more preferable to occupy 95% by weight or more, and even more preferably 95% by weight or more. If it is less than 80% by weight, the ion conductive group content per repeating unit in the aromatic vinyl polymer block (A) decreases, and the density of the ion conductive group also decreases, so that the effect of the present invention is obtained. It may disappear.
  • the weight ratio is calculated assuming a polymer block in which all ion conductive groups of the aromatic vinyl polymer block are substituted with hydrogen (that is, a polymer block having no corresponding ion conductive group).
  • the aromatic vinyl polymer block (A) referred to in the present invention is not limited to those in which the same type of monomer continuously constitutes the main chain, but the aromatic vinyl compound unit is a main repeating unit, and is uniform. Any material capable of forming a phase is included.
  • the phase can be observed with a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • the molecular weight per aromatic vinyl polymer block (A) is appropriately selected depending on the properties of the polymer electrolyte, required performance, other polymer components, and the like.
  • the mechanical properties of the resulting polymer electrolyte membrane tend to be high, but when it is too large, it becomes difficult to form and form a block copolymer, and when the molecular weight is small, the microphase separation structure, and thus Since it is difficult to form an ion channel, ion conductivity and mechanical properties tend to be lowered. Therefore, it is important to appropriately select a molecular weight according to required performance.
  • the molecular weight per aromatic vinyl polymer block (A) is calculated as a structure in which an ion conductive group is substituted with hydrogen (that is, a block copolymer having no corresponding ion conductive group), it is calculated in terms of standard polystyrene.
  • the number average molecular weight is usually selected from 1,000 to 1,000,000, preferably selected from the range of 2,000 to 250,000, and selected from 3,000 to 100,000. More preferably, it is selected from 4,000 to 50,000, more preferably from 5,000 to 25,000. Further, from the viewpoint of ease of solution preparation during film formation and film forming properties, it is preferably selected from 5,000 to 10,000.
  • the aromatic vinyl polymer block (A) may be crosslinked by a known method within a range not impairing the effects of the present invention. By introducing cross-linking, the ion channel phase formed by the aromatic vinyl polymer block (A) is less likely to swell, and changes in mechanical properties (such as tensile properties) between drying and wetting tend to be further reduced. It is in.
  • the number of moles of ion conductive groups per 1 g of aromatic vinyl polymer block (A) is preferably 4.8 meq / g or more in order to exhibit the effects of the present invention. .1 meq / g or more is more preferable, and 5.6 meq / g or more is even more preferable.
  • the ion conductive group possessed by the aromatic vinyl polymer block (A) is not particularly limited, and a functional group having ion conductivity can be used, particularly those having high affinity with anions and / or cations, Those in which some of the functional groups are easily dissociated as ions are suitable, and examples thereof include sulfonic acid groups, phosphonic acid groups, carboxylic acid groups, quaternary ammonium salts, and quaternary salts of pyridine.
  • a proton conductive group or a salt obtained by exchanging protons of the proton conductive group with other ions is excellent in proton conductivity, and examples thereof include sulfonic acid groups, phosphonic acid groups, carboxylic acid groups, and salts thereof.
  • sulfonic acid groups and phosphonic acid groups and their salts are preferably used.
  • the ion exchange capacity can be adjusted by appropriately selecting the type and concentration of the ion conductive group.
  • the position of the ion conductive group in the aromatic vinyl polymer block (A) is not particularly limited, but it is introduced onto the aromatic ring of the aromatic vinyl compound unit for ease of introduction of the ion conductive group. Is preferred.
  • the block copolymer constituting the polymer electrolyte of the present invention comprises an aliphatic vinyl polymer block (B) as a constituent component.
  • the aliphatic vinyl polymer block (B) has an aliphatic vinyl compound unit as a main repeating unit and does not have an ion conductive group.
  • the aliphatic vinyl compound unit which is the main repeating unit of the aliphatic vinyl polymer block (B), is a structure that can be formed by polymerization of an aliphatic vinyl compound.
  • the aliphatic vinyl compound refers to a compound having at least one functional group containing an addition polymerizable carbon double bond directly bonded to a carbon atom that does not constitute at least one aromatic ring.
  • Examples of the aliphatic vinyl compound unit include alkene units having 2 to 8 carbon atoms, cycloalkene units having 5 to 8 carbon atoms, vinylcycloalkane units having 7 to 10 carbon atoms, and vinylcycloalkene units having 7 to 10 carbon atoms. And conjugated diene units having 4 to 8 carbon atoms and conjugated cycloalkadiene units having 5 to 8 carbon atoms. You may use the repeating unit chosen from these groups individually or in combination of 2 or more types.
  • the form in the case of polymerizing (copolymerizing) two or more kinds may be random copolymerization, block copolymerization, graft copolymerization or tapered copolymerization.
  • the monomer to be polymerized has a plurality of carbon-carbon double bonds
  • any of them may be used for the polymerization.
  • a conjugated diene a plurality of kinds of polymerizable positions (for example, 1, 3 -Diene 1,2-bond, 3,4-bond, 1,4-bond polymerization), but there is no particular limitation, and the ratio (for example, ratio of 1,2-bond to 1,4-bond) ) Is not particularly limited.
  • the alkene having 2 to 8 carbon atoms includes ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 1- Cycloalkene having 5 to 8 carbon atoms such as hexene, 2-hexene, 1-heptene, 2-heptene, 1-octene, 2-octene, etc., and vinyl having 7 to 10 carbon atoms such as cyclopentene, cyclohexene, cycloheptene and cyclooctene
  • cycloalkanes include vinylcyclopentane, vinylcyclohexane, vinylcycloheptane, and vinylcyclooctane.
  • Examples of vinylcycloalkene having 7 to 10 carbon atoms include vinylcyclopentene, vinylcyclohexene, vinylcycloheptene, and vinylcyclooctene.
  • Examples of the conjugated cycloalkadiene having 5 to 8 carbon atoms such as heptadiene and 2,4-heptadiene include cyclopentadiene and 1,3-cyclohexadiene. These monomers may be used independently and may use 2 or more types together.
  • the monomer for forming the aliphatic vinyl polymer block (B) has a plurality of carbon-carbon double bonds as in the case of vinylcycloalkene, conjugated diene or conjugated cycloalkadiene
  • the repeating unit after polymerization has a carbon-carbon double bond
  • a structure in which this is further saturated can be used as the repeating unit. This can be obtained by hydrogenating the remaining carbon-carbon double bond when the monomer is polymerized.
  • a carbon-carbon double bond has a structure in which 30 mol% or more thereof is hydrogenated.
  • the abundance (or hydrogenation rate) of the carbon-carbon double bond can be calculated by a commonly used method, for example, iodine value measurement method, 1 H-NMR measurement or the like.
  • the aliphatic vinyl polymer block (B) has a carbon number of 2 from the viewpoint of giving the resulting block copolymer elasticity and, in turn, good moldability in the production of a membrane-electrode assembly and a polymer electrolyte fuel cell. It consists of alkene units of ⁇ 8, cycloalkene units of 5 to 8 carbon atoms, vinylcycloalkene units of 7 to 10 carbon atoms, conjugated diene units of 4 to 8 carbon atoms and conjugated cycloalkadiene units of 5 to 8 carbon atoms.
  • preferred as the alkene unit are structural units saturated with double bonds of isobutene units, 1,3-butadiene units (1-butene units, 2-butene units), and structural units saturated with double bonds of isoprene units.
  • the aliphatic vinyl compound unit is the main repeating unit, that is, the aliphatic vinyl compound unit exceeds 50% by weight and exceeds 70% by weight. Preferably, it exceeds 90% by weight.
  • the aliphatic vinyl polymer block (B) has other repeating units as long as the purpose of the aliphatic vinyl polymer block (B) to give elasticity to the block copolymer is not impaired.
  • aromatic vinyl compound units such as styrene units and vinylnaphthalene units, halogen-containing vinyl compound units such as vinyl chloride units, acrylate ester units having 1 to 12 carbon side chains, and sides having 1 to 12 carbon atoms It may contain a methacrylic ester unit having a chain.
  • the copolymerization form of the monomer and the other monomer is random copolymerization.
  • the amount of such other monomer used is less than 50% by weight of the aliphatic vinyl polymer block (B), more preferably less than 30% by weight, and even more preferably less than 10% by weight. preferable.
  • the aliphatic vinyl polymer block (B) is a rubber-like polymer block
  • the block copolymer becomes elastic and flexible as a whole, and a membrane-electrode assembly and a polymer electrolyte fuel cell are produced.
  • formability assembling property, joining property, tightening property, etc.
  • the rubber-like polymer block here means a polymer block having a glass transition point or softening point of 30 ° C. or lower, preferably 20 ° C. or lower, more preferably 10 ° C. or lower.
  • the main component is at least one repeating unit selected from the group consisting of a vinylcycloalkene unit having 10 to 10, a conjugated diene unit having 4 to 8 carbon atoms, and a conjugated cycloalkadiene unit having 5 to 8 carbon atoms, More preferably, the main component is at least one repeating unit selected from the group consisting of alkene units having 2 to 5 carbon atoms and conjugated diene units having 4 to 5 carbon atoms.
  • the molecular weight per aliphatic vinyl polymer block (B) is appropriately selected depending on the properties of the polymer electrolyte, required performance, other polymer components, and the like.
  • the number average molecular weight in terms of standard polystyrene is usually selected from 1,000 to 1,000,000, preferably from 5,000 to 500,000, and preferably 10,000 to 200,000. It is more preferable to select between.
  • the aliphatic vinyl polymer block (B) is a rubbery polymer block, it is particularly selected from 15,000 to 120,000 from the viewpoint of achieving both moldability and flexibility. preferable.
  • the aliphatic vinyl polymer block (B) does not have an ion conductive group.
  • having no ion-conducting group means that the ion-conducting group is not substantially ion-conducting, and enhances microphase separation from the aromatic vinyl polymer block (A).
  • the ion conductive group content per repeating unit is preferably 0.1 or less, more preferably 0.01 or less, and most preferably not at all. However, in production, it may be advantageous to contain about 0.001 to 0.05 ion conductive groups per repeating unit.
  • the aliphatic vinyl polymer block (B) is hydrophobic, phase separation with the aromatic vinyl polymer block (A) occurs favorably.
  • it is preferably substantially free of hydrophilic groups such as hydroxyl groups and amino groups, and it is also preferred that substantially no polar groups such as ester groups are present.
  • the block structure of the block copolymer comprising the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) as constituent components is not particularly limited, the aromatic vinyl polymer block (A) It is desirable that there is a plurality, and that both ends of at least one aliphatic vinyl polymer block (B) are not terminals of the block copolymer.
  • Examples include an ABA type triblock copolymer, an ABBA type triblock copolymer and an AB type diblock copolymer, an ABBA type AB block copolymer.
  • Block copolymers may be used alone or in combination of two or more.
  • the block copolymer has a plurality of aromatic vinyl polymer blocks (A) and / or aliphatic vinyl polymer blocks (B), these blocks may be the same or different. .
  • the weight ratio of the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) constituting the block copolymer is obtained.
  • it is appropriately selected depending on the required performance of the block copolymer to be obtained, it is preferably 95: 5 to 55:45 from the viewpoint of ionic conductivity, and 45:55 to 5:95 is preferable from the viewpoint of water resistance. In order to achieve both ionic conductivity and water resistance, 60:40 to 40:60 is preferable.
  • this weight ratio is 95: 5 to 5:95, it is advantageous for the ion channel formed by the aromatic vinyl polymer block (A) to be a cylindrical or continuous phase by microphase separation.
  • the hydrophobic vinyl polymer block (B) which is hydrophobic, has an appropriate ratio and exhibits excellent water resistance.
  • the weight ratio is calculated assuming a polymer block in which all ion conductive groups of the block copolymer are replaced with hydrogen.
  • the block copolymer used in the present invention includes those partially containing graft bonds.
  • Examples of the block copolymer partially containing a graft bond include those in which a part of the constituting polymer block is grafted to the main structure (for example, main chain) of the block copolymer.
  • the number average molecular weight of the block copolymer used in the present invention is not particularly limited, but the number average molecular weight not considering the ion conductive group is usually 10,000 to 1,000,000 as the number average molecular weight in terms of standard polystyrene. Preferably, 15,000 to 700,000 is more preferable, and 20,000 to 500,000 is even more preferable.
  • the block copolymer constituting the polymer electrolyte of the present invention needs to have an ion conductive group in the aromatic vinyl polymer block (A).
  • ions in the present invention when referring to ionic conductivity include protons.
  • the ion conductive group is not particularly limited as long as the membrane-electrode assembly produced using the polymer electrolyte can exhibit sufficient ionic conductivity, and in particular, —SO 3 M or —PO
  • a sulfonic acid group, a phosphonic acid group or a salt thereof represented by 3 HM (wherein M represents a hydrogen atom, an ammonium ion or an alkali metal ion) is preferably used.
  • a carboxyl group or a salt thereof can also be used.
  • the aromatic vinyl polymer block (A) having an ion conductive group is particularly effective for improving the radical resistance of the polymer electrolyte.
  • the amount of ion-conducting group introduced is appropriately selected depending on the required performance of the resulting block copolymer, etc., but exhibits sufficient ion conductivity for use as a polymer electrolyte membrane for a polymer electrolyte fuel cell.
  • the block copolymer has an ion exchange capacity (overall IEC) of 0.40 meq / g or more, and preferably 0.50 meq / g or more. It is more preferable that the amount is 0.60 meq / g or more.
  • the upper limit of the ion exchange capacity of the block copolymer is preferably 4.5 meq / g or less, because if the ion exchange capacity becomes too large, the hydrophilicity tends to increase and the water resistance tends to be insufficient. It is more preferably 0.0 meq / g or less, and further preferably 3.5 meq / g or less.
  • the block copolymer used in the present invention may contain an aromatic vinyl polymer block (C) mainly comprising an aromatic vinyl compound unit having no ion conductive group as a repeating unit.
  • the aromatic vinyl polymer block (C) accounts for 20 to 60% by weight of the polymer electrolyte, it is excellent in mechanical strength when used as a membrane, which is preferable. More preferably, it occupies 23 to 50% by weight, and further preferably occupies 25 to 40% by weight.
  • the aromatic vinyl polymer block (C) having an aromatic vinyl compound unit mainly having no ion conductive group as a repeating unit is a polymer block having an aromatic vinyl compound unit as a main repeating unit.
  • the polymer block is excellent in shape stability of a polymer electrolyte molded body (for example, a polymer electrolyte membrane). Therefore, it is particularly useful when the aliphatic vinyl polymer block (B) is a rubbery polymer block.
  • the aromatic vinyl polymer block (C) is preferably phase-separated from both the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) to form a constrained phase. That is, since the aromatic vinyl polymer block (C) having no ionic conductivity forms an independent phase, the shape stability is further improved.
  • the aromatic vinyl polymer block (C) is mainly composed of an aromatic vinyl compound unit having no ion conductive group as a repeating unit.
  • the aromatic vinyl-based compound unit having mainly no ion-conducting group as a repeating unit means that the aromatic vinyl-based polymer block (C) has substantially no ion conductivity.
  • the ion conductive group content per repeating unit of the aromatic vinyl polymer block (C) is 0.1 or less, more preferably 0.01 or less, and most preferably not at all. It is. Alternatively, it is preferably 1/10 or less, more preferably 1/20, and even more preferably 1/100 or less with respect to the ion conductive group of the aromatic vinyl polymer block (A). .
  • the aromatic vinyl polymer block (C) does not substantially have ionic conductivity, and phase separation with the aromatic vinyl polymer block (A) forming the ion channel is favorably expressed. Efficient ion conduction can be performed.
  • aromatic vinyl polymer block (C) is hydrophobic, phase separation with the aromatic vinyl polymer block (A) occurs favorably.
  • it is preferably substantially free of hydrophilic groups such as hydroxyl groups and amino groups, and it is also preferred that substantially no polar groups such as ester groups are present.
  • the aromatic vinyl compound unit which is the main repeating unit of the aromatic vinyl polymer block (C) is a structure which can be formed by polymerization of an aromatic vinyl compound.
  • the aromatic vinyl compound refers to a compound having at least one functional group containing at least one aromatic ring and an addition polymerizable carbon double bond directly bonded to a carbon atom on at least one aromatic ring.
  • the aromatic ring of the aromatic vinyl compound is preferably a carbocyclic aromatic ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, and a pyrene ring.
  • the aromatic vinyl compound unit is preferably a substituted aromatic vinyl compound unit having 1 to 3 hydrocarbon groups having 1 to 8 carbon atoms on the aromatic ring. Examples thereof include compounds in which hydrogen on the aromatic ring is substituted with a substituent such as a vinyl group, 1-alkylethenyl group (eg, isopropenyl group), 1-arylethenyl group.
  • styrene 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, 4-n-propylstyrene, 4-isopropylstyrene, 4-n-butylstyrene, 4-isobutylstyrene, 4- t-butylstyrene, 4-n-octylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,5-dimethylstyrene, 2,4,6-trimethylstyrene, 2-methoxystyrene, 3-methoxy Styrene, 4-methoxystyrene, vinylnaphthalene, vinylanthracene, alkyl groups having 1 to 4 hydrogen atoms bonded to ⁇ -carbon atoms (methyl group, ethyl group, n-propyl group, isopropy
  • the aromatic vinyl polymer block (C) may contain one or more other monomer units within a range not impairing the effects of the present invention.
  • examples of such other monomers include conjugated dienes having 4 to 8 carbon atoms (1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 2,4-hexadiene, 2,3- Dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-heptadiene, 1,4-heptadiene, 3,5-heptadiene, etc.), alkenes having 2 to 8 carbon atoms (ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-heptene, 2-heptene, 1-octene, 2-octene, etc.), (meth) acrylic acid ester (Methyl (meth)
  • the aromatic vinyl polymer block (C) is preferably used in the range of 60% by weight or less of the block copolymer, more preferably in the range of 50% by weight or less, and in the range of 40% by weight or less. Is more preferable.
  • the ratio of the aromatic vinyl polymer block (C) to the aromatic vinyl polymer block (A) is not particularly limited, but the ratio of the monomer units before introducing the ion conductive group is 85: It is preferably in the range of 15 to 0: 100, and in the range of 65:35 to 20:80 in order to achieve both the mechanical strength of the aromatic vinyl polymer block (C) and high ionic conductivity. Preferably, it is in the range of 55:45 to 35:65, more preferably in the range of 45:55 to 35:65.
  • the aromatic vinyl polymer block (C) may be composed of a polymer block having an aromatic vinyl compound unit represented by the following general formula (a) as a main repeating unit.
  • the alkyl group having 1 to 4 carbon atoms represented by R 1 in the general formula (a) may be linear or branched, and is a methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group. , Isobutyl group, tert-butyl group and the like.
  • the alkyl group having 1 to 8 carbon atoms represented by R 2 to R 4 in the general formula (a) may be linear or branched, and is methyl, ethyl, propyl, isopropyl, butyl, sec -Butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, 1-methylpentyl group, heptyl group, octyl group and the like.
  • aromatic vinyl compound unit represented by the general formula (a) include 4-methylstyrene unit, 4-tert-butylstyrene unit, ⁇ , 4-dimethylstyrene unit, ⁇ -methyl-4. -Tert-butylstyrene units and the like may be mentioned, and these may be used alone or in combination of two or more.
  • the form in the case of polymerizing (copolymerizing) two or more of these may be random copolymerization, block copolymerization, graft copolymerization, or tapered copolymerization.
  • R 1 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms
  • R 2 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, but at least one of them is carbon Represents an alkyl group of 1 to 8)
  • the polymer electrolyte of the present invention there is a method of introducing an ion conductive group after producing a block copolymer having no ion conductive group.
  • an ion conductive group for example, when a sulfonic acid group is introduced as an ion conductive group, the sulfonation reaction of polystyrene takes place preferentially at the para position of the aromatic ring, so that the main repeating unit of the aromatic vinyl polymer block is the 4-methylstyrene unit.
  • the aromatic vinyl polymer block (C) is obtained by polymerization of an aromatic vinyl compound (for example, a substituted aromatic vinyl compound) in which introduction of an ion conductive group is unlikely to occur. It is possible to use a monomer that is sufficiently less reactive in introducing an ion conductive group than an aromatic vinyl compound (for example, an unsubstituted aromatic vinyl compound) for constituting the combined block (A). It is advantageous in producing the polymer electrolyte of the present invention by a method of introducing an ion conductive group after producing a block copolymer not having it.
  • the polymer electrolyte of the present invention is produced by a method of introducing an ion conductive group into the block copolymer, it corresponds to the aromatic vinyl polymer block (C) in the block copolymer before the introduction of the ion conductive group.
  • the aromatic vinyl polymer block is very difficult to introduce an ion conductive group.
  • the ion conductive group introduction rate of the polymer block (A) is significantly higher than that of the aromatic vinyl polymer block (C) in all cases.
  • the ion conductive group of the aromatic vinyl polymer block (A) preferably occupies at least 85%, more preferably 90% or more of the total ion conductive group of the block copolymer, 95% It is more preferable to occupy the above.
  • the above-described aromatic vinyl compound unit is the main repeating unit of the aromatic vinyl polymer block (C) and exceeds 50% by weight. Further, it is more preferably 70% by weight or more, and still more preferably 90% by weight or more.
  • the molecular weight of the aromatic vinyl polymer block (C) is appropriately selected depending on the properties of the polymer electrolyte, required performance, other polymer components, and the like. When the molecular weight is large, the mechanical properties of the polymer electrolyte tend to be high, but when it is too large, it becomes difficult to mold and form a block copolymer, and when the molecular weight is small, the mechanical properties tend to be low, It is important to select the molecular weight appropriately according to the required performance.
  • the number average molecular weight in terms of standard polystyrene is usually preferably selected from 800 to 500,000, more preferably from 2,000 to 150,000, more preferably from 3,000 to 50,000. More preferably, it is selected from among 000.
  • the block copolymer used in the present invention comprises an aromatic vinyl polymer block (C), an aromatic vinyl polymer block (A) and an aliphatic vinyl polymer block (B), the block copolymer
  • the structure of the polymer is not particularly limited, but examples include an ABCA tetrablock copolymer, an ABBC tetrablock copolymer, and an ABCB tetrablock copolymer.
  • Copolymer C—B—C—A tetrablock copolymer, A—B—A—C tetra block copolymer, A—C—B—C—A penta block copolymer, C—A—B—A -C pentablock copolymer, ABCCBCA pentablock copolymer, CBABBC pentablock copolymer, ABCBAB block Polymer, ABCA-A-C pentablock copolymer, AB C—B—C—Pentablock copolymer, A—A—A—B—C—Penta block copolymer, A—A—A—C—B—Penta block copolymer, B—A—B—A—C Pentablock copolymer, BACBCA pentablock copolymer, BABBCB pentablock copolymer, CACBBC pentablock copolymer Etc.
  • C blocks From the viewpoint of restraint, it is preferable to have a plurality of C blocks, and it is particularly preferable to have C blocks at both ends. Moreover, when emulsifying and using the polymer electrolyte of this invention, it is preferable to have A block at both ends from a viewpoint of the ease of preparation of an emulsion. Further, from the viewpoint of solubility and dispersibility in an organic solvent, a C—A—C—B—C pentablock copolymer is desirable.
  • the block copolymer used in the present invention includes those partially containing graft bonds.
  • Examples of the block copolymer partially containing a graft bond include those in which a part of the constituting polymer block is graft-bonded to a main part (for example, main chain) of the block copolymer.
  • the production method of the block copolymer in the polymer electrolyte used in the present invention is not particularly limited, and a known method can be used, but after producing the block copolymer having no ion conductive group.
  • a method of bonding an ion conductive group is preferable.
  • a polymer block having no ion conductive group corresponding to the aromatic vinyl polymer block (A) in the block copolymer having no ion conductive group is referred to as an aromatic vinyl polymer block (A ) '.
  • the production method of the polymer block (B) is appropriately selected from a radical polymerization method, an anionic polymerization method, a cationic polymerization method, a coordination polymerization method, and the like. From the industrial easiness, a radical polymerization method and an anionic polymerization method are used.
  • the cationic polymerization method is preferably selected.
  • the so-called living polymerization method is preferable from the viewpoints of molecular weight control, molecular weight distribution control, polymer structure control, ease of bonding between the aromatic vinyl polymer block (A) ′ and the aliphatic vinyl polymer block (B), and the like.
  • a living radical polymerization method, a living anion polymerization method, and a living cation polymerization method are preferable.
  • Specific examples of the production method include an aromatic vinyl polymer block (A) ′ having an aromatic vinyl compound such as 4-vinylbiphenyl as a main repeating unit and an aliphatic vinyl polymer block (B) comprising a conjugated diene.
  • a method for producing a block copolymer containing as a component will be described. In this case, it is produced by a living anionic polymerization method from the viewpoint of industrial ease, molecular weight, molecular weight distribution, ease of bonding between the aromatic vinyl polymer block (A) ′ and the aliphatic vinyl polymer block (B), and the like. And the following specific synthesis examples are shown.
  • An aromatic vinyl compound such as 4-vinylbiphenyl is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then conjugated diene, 4-vinylbiphenyl, etc.
  • a method of sequentially polymerizing aromatic vinyl compounds to obtain an A′-BA ′ type block copolymer is provided.
  • An aromatic vinyl compound such as 4-vinylbiphenyl is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then conjugated diene is polymerized.
  • aromatic vinyl polymer block (C) having an aromatic vinyl compound such as 4-tert-butylstyrene as the main repeating unit, and aromatic vinyl compounds such as 4-vinylbiphenyl.
  • a method for producing a block copolymer comprising as constituent components an aromatic vinyl polymer block (A) ′ as a repeating unit and a polymer block (B) comprising a conjugated diene will be described.
  • the living anionic polymerization method is preferred from the viewpoint of industrial ease, molecular weight, molecular weight distribution, ease of bonding of polymer blocks (C), (B) and (A) ′, and the following specific synthesis Examples are given and can be adopted / applied.
  • An aromatic vinyl compound such as 4-tert-butylstyrene is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then conjugated diene, 4-vinylbiphenyl
  • a method of obtaining a CBA ′ type block copolymer by sequentially polymerizing aromatic vinyl compounds such as
  • An aromatic vinyl compound such as 4-tert-butylstyrene is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then an aromatic such as 4-vinylbiphenyl is used.
  • An aromatic vinyl compound such as 4-tert-butylstyrene is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then an aromatic such as 4-vinylbiphenyl.
  • C—A′-BA—C type block by sequentially polymerizing aromatic vinyl compounds such as aromatic vinyl compounds, conjugated dienes, 4-vinylbiphenyl, and aromatic vinyl compounds such as 4-tert-butylstyrene A method for obtaining a copolymer.
  • the block copolymer thus produced is subjected to a hydrogenation reaction of double bonds of conjugated diene units having 4 to 8 carbon atoms constituting the aliphatic vinyl polymer block (B).
  • a hydrogenation reaction a solution of a block copolymer obtained by anionic polymerization or the like is charged into a pressure vessel, and a hydrogenation reaction is performed in a hydrogen atmosphere using a Ziegler type hydrogenation catalyst such as a Ni / Al type. The method of performing can be illustrated.
  • Sulfonation can be performed by a known sulfonation method.
  • a sulfonation method an organic solvent solution or suspension of a block copolymer is prepared, a sulfonating agent is added and mixed, a method of adding a gaseous sulfonating agent directly to the block copolymer, etc. Is exemplified.
  • Sulfonating agents used include sulfuric acid, a mixture of sulfuric acid and aliphatic acid anhydride, chlorosulfonic acid, a mixture of chlorosulfonic acid and trimethylsilyl chloride, sulfur trioxide, a mixture of sulfur trioxide and triethyl phosphate.
  • aromatic organic sulfonic acids represented by 2,4,6-trimethylbenzenesulfonic acid.
  • organic solvent to be used include halogenated hydrocarbons such as methylene chloride, linear aliphatic hydrocarbons such as hexane, cyclic aliphatic hydrocarbons such as cyclohexane, and the like. You may use it, selecting suitably from several combinations.
  • a method for removing the sulfonated product as a solid from the reaction solution containing the sulfonated product of the block copolymer a method of pouring the reaction solution into water and precipitating the sulfonated product, and then distilling off the solvent at atmospheric pressure, Stopper water is gradually added and suspended in the reaction solution, and the sulfonated product is precipitated, and then the solvent is distilled off at atmospheric pressure. From the viewpoint of increasing the washing efficiency, a method of gradually adding and suspending the stopper water in the reaction solution to precipitate the sulfonated product is suitably used.
  • Phosphonation can be performed by a known phosphonation method. Specifically, for example, an organic solvent solution or suspension of a block copolymer is prepared, and the copolymer is reacted with chloromethyl ether or the like in the presence of anhydrous aluminum chloride to introduce a halomethyl group into the aromatic ring. Thereafter, there may be mentioned a method in which phosphorus trichloride and anhydrous aluminum chloride are added and reacted, followed by a hydrolysis reaction to introduce a phosphonic acid group.
  • a method may be exemplified in which phosphorus trichloride and anhydrous aluminum chloride are added to the copolymer and reacted to introduce a phosphinic acid group into the aromatic ring, and then the phosphinic acid group is oxidized with nitric acid to form a phosphonic acid group.
  • the ion exchange capacity of the block copolymer is preferably 0.40 meq / g or more, more preferably 0.50 meq / g or more, and further preferably 0.60 meq / g.
  • the ion exchange capacity of the sulfonated or phosphonated block copolymer, or the sulfonation rate or phosphonation rate in the aromatic vinyl compound in the block copolymer is determined by acid value titration, infrared spectroscopic measurement, nuclear It can be calculated using analytical means such as magnetic resonance spectrum ( 1 H-NMR spectrum) measurement.
  • the ion conductive group may be introduced in the form of a salt neutralized with a suitable metal ion (for example, alkali metal ion) or counter ion (for example, ammonium ion).
  • a suitable metal ion for example, alkali metal ion
  • counter ion for example, ammonium ion
  • a block copolymer having a sulfonic acid group in a salt form can be obtained by ion exchange by an appropriate method.
  • the polymer electrolyte of the present invention can be added to various additives such as a softening agent, a stabilizer, a light stabilizer, an antistatic agent, a release agent, a flame retardant, a foaming agent, a pigment, and a dye as long as the effects of the present invention are not impaired. Further, each of them may contain a brightener or the like alone or in combination of two or more.
  • softener examples include petroleum softeners such as paraffinic, naphthenic or aromatic process oils, paraffin, vegetable oil softeners, plasticizers, and the like.
  • Stabilizers include phenol-based stabilizers, sulfur-based stabilizers, phosphorus-based stabilizers, and the like. Specific examples include 2,6-di-t-butyl-p-cresol, pentaerythryl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) Benzene, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, 2,2-thio-diethyleneb
  • the content of the block copolymer in the polymer electrolyte of the present invention is preferably 50% by weight or more, more preferably 70% by weight or more, and 90% by weight or more. It is even more preferable.
  • the polymer electrolyte membrane of the present invention suitable for use in a polymer electrolyte fuel cell or the like preferably has a thickness of about 5 to 300 ⁇ m, preferably 6 to 200 ⁇ m, from the viewpoints of membrane resistance, membrane strength, handling properties, and the like. More preferably, it is about 7 to 100 ⁇ m. When it is desired to lower the membrane resistance, 7 to 30 ⁇ m is preferable. When the membrane resistance is kept low and the membrane strength is increased, 20 to 60 ⁇ m is preferable. When the membrane strength is important, 50 to 100 ⁇ m is preferable.
  • any method for preparing the polymer electrolyte membrane any method can be adopted as long as it is a normal method for such preparation.
  • a solution coating method for obtaining a polymer electrolyte membrane having a desired thickness, or a polytetrafluoroethylene sheet or the like of 5% by weight or less a solution coating method for obtaining a polymer electrolyte membrane having a desired thickness, or a polytetrafluoroethylene sheet or the like of 5% by weight or less.
  • the solvent is gradually removed over 1 to several days to obtain a polymer electrolyte membrane having a desired thickness.
  • a method of forming a film using a known method such as a cast method, hot press molding, roll molding, extrusion molding, etc. can be used, but it is easy to adjust a polymer electrolyte membrane having good strength and flexibility. Therefore, the solution coating method is preferably used.
  • the same or different block copolymer solution may be newly applied on the obtained polymer electrolyte membrane layer and dried to be laminated. Further, the same or different polymer electrolyte membranes obtained as described above may be laminated by being pressure-bonded by hot roll molding or the like.
  • the solvent used when preparing the polymer electrolyte membrane in a uniform solution system is capable of preparing a solution having a viscosity that allows solution coating without destroying the structure of the block copolymer. If there is no particular limitation. Specifically, halogenated hydrocarbons such as methylene chloride and chlorobenzene, aromatic hydrocarbons such as toluene, xylene, and benzene, linear aliphatic hydrocarbons such as hexane and heptane, and cyclic fats such as cyclohexane.
  • halogenated hydrocarbons such as methylene chloride and chlorobenzene
  • aromatic hydrocarbons such as toluene, xylene, and benzene
  • linear aliphatic hydrocarbons such as hexane and heptane
  • cyclic fats such as cyclohexane.
  • Examples include aromatic hydrocarbons, ethers such as tetrahydrofuran, alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol and isobutyl alcohol, or mixed solvents thereof.
  • ethers such as tetrahydrofuran
  • alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol and isobutyl alcohol, or mixed solvents thereof.
  • one or more combinations can be appropriately selected and used from the solvents exemplified above.
  • a mixed solvent of benzene and methanol, chlorobenzene is preferable, and a mixed solvent of toluene and isobutyl alcohol, a mixed solvent of toluene and isopropyl alcohol, and chlorobenzene are particularly preferable.
  • the aromatic vinyl polymer block (A) having an ion conductive group is hydrophilic and the aliphatic vinyl polymer block (B) is hydrophobic, it has a protective colloid forming ability, and a surfactant is used.
  • An emulsion can be obtained without any problems. Further, by using a polar solvent such as water, particles having an ion conductive group having a high polarity in the outer shell can be easily produced.
  • a known method can be used as a method for preparing the emulsion, it is preferable to apply the phase inversion emulsification method in that the distribution of the dispersed particle diameter can be narrowed. That is, a polar solvent such as water is added while stirring a solution obtained by dissolving the block polymer in a suitable organic solvent with an emulsifier. Initially, a polar solvent such as water is dispersed in the organic solvent system as particles, but when the polar solvent exceeds a certain amount, it becomes a co-continuous state, and the viscosity rapidly increases. Further, when a polar solvent is added, the polar solvent becomes a continuous phase and the organic solvent becomes fine particles, and the viscosity rapidly decreases. By using this method, an emulsion having a uniform dispersed particle size can be obtained.
  • the block polymer When the dispersion particle size of the emulsion is larger than 1 ⁇ m, the block polymer has a phase-separated structure within the particle, and not all ion conductive groups have come out in the outer shell. It cannot be used effectively. Therefore, when a block polymer is used, it is desirable to make fine particles until the average dispersed particle size is 1 ⁇ m or less, depending on the molecular weight of the polymer used and the block ratio. In many cases, since the average dispersed particle size in the pre-emulsification is 1 ⁇ m or more, further fine dispersion is required.
  • a known method can be used, but a method that does not use a medium such as a ball for grinding in a ball mill is preferable from the viewpoint of preventing impurities from being mixed.
  • Specific examples include a high-pressure collision method.
  • the solvent removal conditions in the solution coating method may be arbitrarily selected as long as the conditions are such that the solvent can be completely removed at a temperature equal to or lower than the temperature at which ion conductive groups such as sulfonic acid groups of the block copolymer are removed. Is possible.
  • a plurality of temperatures may be arbitrarily combined, or a combination of ventilation and vacuum may be arbitrarily combined. Specifically, a method of removing the solvent by hot air drying at about 60 to 100 ° C. over 4 minutes, a method of removing the solvent in 2 to 4 minutes by hot air drying at about 100 to 140 ° C., After preliminarily drying at about 25 ° C.
  • Examples include a method of drying for about 1 to 12 hours by vacuum drying under an atmosphere of about 40 ° C. From the viewpoint of easy preparation of a polymer electrolyte membrane having good strength and flexibility, a method of removing the solvent by hot air drying at about 60 to 100 ° C. over 4 minutes, or about 1 to 3 hours at about 25 ° C. Then, after pre-drying, dry with hot air drying at about 100 ° C. over several minutes, or after pre-drying at about 25 ° C. for about 1 to 3 hours and then in an atmosphere at about 25-40 ° C. under vacuum A method of drying for about 1 to 12 hours by drying is preferably used.
  • the membrane-electrode assembly of the present invention using a polymer electrolyte membrane produced from the polymer electrolyte of the present invention will be described.
  • a known method can be applied.
  • a catalyst paste containing an ion conductive binder is applied on the gas diffusion layer by a printing method or a spray method and dried.
  • a solution or suspension containing an ion conductive binder is applied to both surfaces of the polymer electrolyte membrane and / or the catalyst layer surface of a pair of gas diffusion electrodes, and the polymer electrolyte membrane and the catalyst layer surface There is a method of bonding them together by thermocompression bonding.
  • the solution or suspension may be applied to one or both of the polymer electrolyte membrane and the catalyst layer surface.
  • the catalyst paste is applied to a base film made of polytetrafluoroethylene (PTFE) and dried to form a catalyst layer, and then a pair of base films on the base film is formed.
  • PTFE polytetrafluoroethylene
  • the catalyst layer is transferred to both sides of the polymer electrolyte membrane by thermocompression bonding, and the base film is peeled off to obtain a joined body of the polymer electrolyte membrane and the catalyst layer.
  • a gas diffusion layer is formed on each catalyst layer by hot pressing.
  • Examples of the ion conductive binder constituting the membrane-electrode assembly include existing perfluorosulfones such as “Nafion” (registered trademark, manufactured by DuPont) and “Gore-select” (registered trademark, manufactured by Gore).
  • An ion conductive binder made of an acid polymer, an ion conductive binder made of a sulfonated polyethersulfone or a sulfonated polyetherketone, an ion conductive binder made of polybenzimidazole impregnated with phosphoric acid or sulfuric acid can be used. .
  • an ion conductive binder from the block copolymer which comprises the polymer electrolyte membrane of this invention.
  • the polymer electrolyte membrane is composed of a plurality of materials such as a multilayer structure
  • the polymer electrolyte constituting the surface in contact with the gas diffusion electrode of the polymer electrolyte membrane, or the same type of material as the polymer electrolyte that is the main component of the surface More preferably, an ion conductive binder formed from the same material is used.
  • the constituent material of the catalyst layer of the membrane-electrode assembly is not particularly limited as the conductive material / catalyst support, and examples thereof include carbon materials.
  • the carbon material include carbon black such as furnace black, channel black, and acetylene black, activated carbon, graphite, and the like. These may be used alone or in combination of two or more.
  • the catalyst metal may be any metal that promotes the oxidation reaction of fuel such as hydrogen or methanol and the reduction reaction of oxygen, such as platinum, gold, silver, palladium, iridium, rhodium, ruthenium, iron, Cobalt, nickel, chromium, tungsten, manganese, palladium, etc., or alloys thereof, for example, platinum-ruthenium alloy can be mentioned.
  • the particle size of the metal serving as a catalyst is usually 10 to 300 angstroms.
  • the catalyst layer may contain a water repellent as necessary.
  • the water repellent include various thermoplastic resins such as polytetrafluoroethylene, polyvinylidene fluoride, styrene butadiene copolymer, and polyether ether ketone.
  • the gas diffusion layer of the membrane-electrode assembly is made of a material having conductivity and gas permeability, and examples of such a material include porous materials made of carbon fibers such as carbon paper and carbon cloth. Moreover, in order to improve water repellency, this material may be subjected to water repellency treatment.
  • the membrane-electrode assembly of the present invention uses a pure hydrogen type using hydrogen as a fuel gas, a methanol reforming type using hydrogen obtained by reforming methanol, and hydrogen obtained by reforming natural gas. Natural gas reforming type, gasoline reforming type using hydrogen obtained by reforming gasoline, direct methanol type using methanol directly, etc. is there.
  • the polymer electrolyte membrane comprising the polymer electrolyte of the present invention has high proton conductivity at low humidity and low resistance, and the membrane-electrode assembly comprising the polymer electrolyte membrane uses hydrogen as a fuel.
  • the membrane-electrode assembly comprising the polymer electrolyte membrane uses hydrogen as a fuel.
  • the number average molecular weight was measured by the gel permeation chromatography (GPC) method under the following conditions.
  • Device manufactured by Tosoh Corporation, trade name: HLC-8220GPC Eluent: THF
  • Column manufactured by Tosoh Corporation, trade name: 1 TSK-GEL (TSKgel G3000HxL (inner diameter 7.6 mm, effective length 30 cm)), TSKgel Super Multipore HZ-M (inner diameter 4.6 mm, effective length 15 cm) 3 in total)
  • Detector RI Liquid feed amount: 0.35 ml / min
  • Number average molecular weight calculation Standard polystyrene conversion
  • the number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSVBtBSItBS is 35,000, the 1,4-bond amount determined from 1 H-NMR measurement is 93.0%, and the content of 4-vinylbiphenyl units is included. The amount was 36.6% by weight, and the content of 4-tert-butylstyrene units was 30.4% by weight.
  • tBSVBtBSEPtBS poly(2-tert-butylstyrene) -b-poly (4-vinylbiphenyl) -b-poly (4-tert-butylstyrene) -b-hydrogenated polyisoprene-b-poly (4-tert- Butylstyrene)
  • tBSVBIVBtBS poly (4-tert-butylstyrene) -b-poly (4-vinylbiphenyl) -b-polyisoprene-b -Poly (4-vinylbiphenyl) -b-poly (4-tert-butylstyrene)
  • the number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSVBIVBtBS is 158,000, the 1,4-bond amount determined from 1 H-NMR measurement is 94.0%, and the content of 4-vinylbiphenyl units The amount was 33.9% by weight, and the content of 4-tert-butylstyrene units was 22.0% by weight.
  • tBSVBEPVBtBS Poly (4-tert-butylstyrene) -b-poly (4-vinylbiphenyl) -b-hydrogenated polyisoprene-b-poly (4-vinylbiphenyl) -b-poly (4-tert-butylstyrene)
  • ⁇ Reference Example 3> (Production of block copolymer consisting of polystyrene, hydrogenated polyisoprene and poly (4-tert-butylstyrene))
  • Into a 1400 mL autoclave 820 ml of dehydrated cyclohexane and 1.7 ml of sec-butyllithium (1.25 M-cyclohexane solution) were charged, and then 19.8 ml of 4-tert-butylstyrene and 27.7 ml of styrene were successively added at 50 ° C.
  • tBSSIStBS Polystyrene-b-polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene)
  • the number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSSIStBS was 86,000, the 1,4-bond content determined from 1 H-NMR measurement was 94.0%, and the styrene unit content was 32. The content of 9.9% by weight and 4-tert-butylstyrene unit was 29.8% by weight.
  • tBSSEPStBS poly (4-tert-butylstyrene) -b-polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene)
  • tBSSIStBS polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene)
  • the number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSSIStBS was 72,000, the 1,4-bond amount determined from 1 H-NMR measurement was 94.0%, and the styrene unit content was 29. The content of 4% by weight and 4-tert-butylstyrene unit was 30.0% by weight.
  • tBSSEPStBS poly (4-tert-butylstyrene) -b-polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene)
  • tBSSIStBS Polystyrene-b-polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene)
  • the number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSSIStBS was 64,000, the 1,4-bond content determined from 1 H-NMR measurement was 94.2%, and the styrene unit content was 41.
  • the content of 2-wt% and 4-tert-butylstyrene units was 29.4 wt%.
  • tBSSEPStBS poly (4-tert-butylstyrene) -b-polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene)
  • ⁇ Production Example 1> (Aromatic vinyl polymer block (A) mainly composed of sulfonated 4-vinylbiphenyl units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and aroma mainly composed of 4-tert-butylstyrene)
  • a sulfonated tBSVBtBSEPtBS which is a polymer electrolyte of the present invention.
  • the sulfonic acid group content per repeating unit of the polymer block containing 4-vinylbiphenyl unit modified with sulfonic acid group which is the aromatic vinyl polymer block (A) having sulfonic acid group of the obtained sulfonated tBSVBtBSEPtBS is The titration was 1.96, and the ion exchange capacity of the polymer electrolyte was 3.0 meq / g.
  • ⁇ Production Example 2> (Aromatic vinyl polymer block (A) mainly composed of sulfonated 4-vinylbiphenyl units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and mainly composed of 4-tert-butylstyrene units)
  • Block copolymer composed of aromatic vinyl polymer block (C) (synthesis of sulfonated tBSVBtBSEPtBS) 5 g of the block copolymer (tBSVBtBSEPtBS) obtained in Reference Example 1 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, followed by addition of 200 ml of methylene chloride and stirring at room temperature.
  • a sulfonated tBSVBtBSEPtBS which is a polymer electrolyte of the present invention.
  • the ion exchange capacity of the polymer electrolyte was 2.77 meq / g.
  • Block copolymer composed of aromatic vinyl polymer block (C) (synthesis of sulfonated tBSVBEPVBtBS) 5 g of the block copolymer (tBSVBEPVBtBS) obtained in Reference Example 2 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, and then 180 ml of methylene chloride was added and stirred at room temperature.
  • a sulfonated tBSVBEPVBtBS which is a polymer electrolyte of the present invention.
  • the content of sulfonic acid group per repeating unit of the polymer block containing 4-vinylbiphenyl unit modified with sulfonic acid group, which is the aromatic vinyl polymer block (A) of the obtained sulfonated tBSVBEPVBtBS is 1.54 from titration.
  • the ion exchange capacity of the polymer electrolyte was 2.33 meq / g.
  • Block copolymer consisting of a polymer block (C) (synthesis of sulfonated tBSSEPStBS) 40 g of the block copolymer (tBSSEPStBS) obtained in Reference Example 3 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, and then 500 ml of methylene chloride was added and stirred at room temperature. And dissolved.
  • a sulfonation reagent obtained by reacting 61.4 ml of acetic anhydride and 27.5 ml of sulfuric acid at 0 ° C. in 123 ml of methylene chloride was gradually added dropwise over 5 minutes.
  • 20 ml of distilled water as a stopper was added.
  • 0.7 L of distilled water was slowly poured into the polymer solution to coagulate and precipitate the polymer.
  • the methylene chloride was removed by distillation at atmospheric pressure, followed by filtration.
  • the solid content obtained by filtration was transferred to a beaker, 1.3 L of distilled water was added, and washing was performed with stirring, followed by filtration and recovery.
  • a sulfonated tBSSEPStBS which is a polymer electrolyte not belonging to the present invention.
  • the content of sulfonic acid group per repeating unit of the polymer block containing styrene group modified with sulfonic acid group of the obtained sulfonated tBSSEPStBS is 1.00 from 1 H-NMR analysis, and the ion exchange of the polymer electrolyte The capacity was 2.52 meq / g.
  • Block copolymer consisting of a polymer block (C) (synthesis of sulfonated tBSSEPStBS) 40 g of the block copolymer (tBSSEPStBS) obtained in Reference Example 3 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, and then added with 452 ml of methylene chloride and stirred at room temperature. And dissolved.
  • a sulfonation reagent obtained by reacting 55.5 ml of acetic anhydride and 24.8 ml of sulfuric acid at 0 ° C. in 111 ml of methylene chloride was gradually added dropwise over 5 minutes.
  • 20 ml of distilled water as a stopper was added.
  • 0.7 L of distilled water was slowly poured into the polymer solution to coagulate and precipitate the polymer.
  • the methylene chloride was removed by distillation at atmospheric pressure, followed by filtration.
  • the solid content obtained by filtration was transferred to a beaker, 1.3 L of distilled water was added, and washing was performed with stirring, followed by filtration and recovery.
  • a sulfonated tBSSEPStBS which is a polymer electrolyte not belonging to the present invention.
  • the content of sulfonic acid group per repeating unit of the polymer block containing styrene group modified with sulfonic acid group of the obtained sulfonated tBSSEPStBS is 1.00 from 1 H-NMR analysis, and the ion exchange of the polymer electrolyte The capacity was 2.30 meq / g.
  • Block copolymer composed of aromatic vinyl polymer block (C) (synthesis of sulfonated tBSVBtBSEPtBS) 5 g of the block copolymer (tBSVBtBSEPtBS) obtained in Reference Example 1 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, followed by addition of 200 ml of methylene chloride and stirring at room temperature.
  • a sulfonated tBSVBtBSEPtBS which is a polymer electrolyte not belonging to the present invention.
  • the content of sulfonic acid groups per repeating unit of the polymer block containing a benzene ring of 4-vinylbiphenyl units modified with sulfonic acid groups of the obtained sulfonated tBSVBtBSEPtBS is 1.30 from titration.
  • the ion exchange capacity was 2.17 meq / g.
  • Block copolymer consisting of a polymer block (C) (synthesis of sulfonated tBSSEPStBS) 40 g of the block copolymer (tBSSEPStBS) obtained in Reference Example 5 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, and then added with 540 ml of methylene chloride and stirred at room temperature. And dissolved.
  • a sulfonation reagent obtained by reacting 89.0 ml of acetic anhydride and 51.8 ml of sulfuric acid at 0 ° C. in 44.5 ml of methylene chloride was gradually added dropwise over 5 minutes.
  • 20 ml of distilled water as a stopper was added.
  • 0.6 L of distilled water was slowly poured into the polymer solution to solidify and precipitate the polymer.
  • the methylene chloride was removed by distillation at atmospheric pressure, followed by filtration.
  • the solid content obtained by filtration was transferred to a beaker, 1.3 L of distilled water was added, and washing was performed with stirring, followed by filtration and recovery.
  • a sulfonated tBSSEPStBS which is a polymer electrolyte not belonging to the present invention.
  • the content of sulfonic acid group per repeating unit of the polymer block containing styrene group modified with sulfonic acid group of the obtained sulfonated tBSSEPStBS is 1.00 from 1 H-NMR analysis, and the ion exchange of the polymer electrolyte The capacity was 2.99 meq / g.
  • Example 1 (Production of polymer electrolyte membrane) A 25 wt% toluene / isobutyl alcohol (weight ratio 6/4) solution of the sulfonated tBSVBtBSEPtBS (ion exchange capacity 3.0 meq / g) obtained in Production Example 1 was prepared, and a release-treated PET film [(stock ) “Toyobo Ester Film K1504” manufactured by Toyobo Co., Ltd.] was coated at a thickness of about 250 ⁇ m and dried in a hot air dryer at 100 ° C. for 4 minutes to obtain a film having a thickness of 35 ⁇ m.
  • a release-treated PET film [(stock ) “Toyobo Ester Film K1504” manufactured by Toyobo Co., Ltd.] was coated at a thickness of about 250 ⁇ m and dried in a hot air dryer at 100 ° C. for 4 minutes to obtain a film having a thickness of 35 ⁇ m.
  • Example 2 (Production of polymer electrolyte membrane) A 30% by weight toluene / isobutyl alcohol (weight ratio 6/4) solution of the sulfonated tBSVBtBSEPtBS (ion exchange capacity 2.77 meq / g) obtained in Production Example 2 was prepared, and a release-treated PET film [(Strain ) "Toyobo Ester Film K1504" manufactured by Toyobo Co., Ltd.] with a thickness of about 150 ⁇ m, and dried in a hot air dryer at 100 ° C. for 4 minutes to obtain a 20 ⁇ m thick film.
  • a release-treated PET film [(Strain ) "Toyobo Ester Film K1504" manufactured by Toyobo Co., Ltd.] with a thickness of about 150 ⁇ m, and dried in a hot air dryer at 100 ° C. for 4 minutes to obtain a 20 ⁇ m thick film.
  • Example 3 (Production of polymer electrolyte membrane) A 1% by weight chlorobenzene solution of the sulfonated tBSVBEPVBtBS (ion exchange capacity 2.33 meq / g) obtained in Production Example 3 was prepared and cast into a container made of a polytetrafluoroethylene sheet. By gradually removing the solvent, a 29 ⁇ m thick film was obtained.
  • ⁇ Comparative Example 1> (Production of polymer electrolyte membrane) A 18% by weight toluene / isopropyl alcohol (5/5 by weight) solution of the sulfonated tBSSEPStBS obtained in Production Example 4 was prepared, and a release-treated PET film [“Toyobo Ester Film K1504” manufactured by Toyobo Co., Ltd.] A film having a thickness of about 350 ⁇ m was coated thereon, dried at 100 ° C. for 4 minutes, and then peeled off from the PET film to obtain a film having a thickness of 30 ⁇ m.
  • ⁇ Comparative Example 2> (Production of polymer electrolyte membrane) A 19% by weight toluene / isopropyl alcohol (weight ratio 5/5) solution of the sulfonated tBSSEPStBS obtained in Production Example 5 was prepared, and a release-treated PET film ["Toyobo Ester Film K1504" manufactured by Toyobo Co., Ltd.] A film with a thickness of about 350 ⁇ m was coated thereon, dried at 100 ° C. for 4 minutes, and then peeled off from the PET film to obtain a film with a thickness of 31 ⁇ m.
  • a polymer electrolyte membrane of 1 cm ⁇ 4 cm was sandwiched between a pair of platinum electrodes and attached to an open cell.
  • the measurement cell was installed in a constant temperature and humidity chamber adjusted to a temperature of 80 ° C. and a relative humidity of 30%, and the ionic conductivity of the membrane was measured by an AC impedance method.
  • Table 1 shows the measurement results of ionic conductivity and linear expansion coefficient of the polymer electrolytes used in Examples 1 to 3 and Comparative Examples 1 to 4 and the produced polymer electrolyte membranes.
  • Example 1 has a higher ion conductivity and a lower linear expansion coefficient even if the ion exchange capacity is substantially the same. That is, the polymer electrolyte membrane of the present invention has high ion conductivity and high shape stability in water. The same can be said for the comparison between Example 3 and Comparative Example 2. Moreover, when Example 2 and Comparative Example 4 which show comparable ionic conductivity are compared, Example 2 has a much lower linear expansion coefficient and is excellent in shape stability in water.
  • the polymer electrolyte membrane comprising the polymer electrolyte of the present invention is excellent in ionic conductivity under low humidity. Therefore, the low humidity of the membrane-electrode assembly and the solid polymer fuel cell using the same The output characteristics below are also excellent. Further, the polymer electrolyte membrane is less swollen by water and has good shape stability in water.
  • a membrane-electrode assembly excellent in output characteristics under low humidity and a solid polymer fuel cell can be provided.

Abstract

Disclosed are: a polymer electrolyte which has high ion conductivity even when placed under low-moisture conditions, is swollen with water to a less extent, and can serve as an alternate for fluorine-containing polymer electrolytes such as Nafion; and a polymer electrolyte film, a film-electrode assembly and a solid polymer fuel cell each produced by using the polymer electrolyte. Specifically disclosed are: a polymer electrolyte comprising a block copolymer composed of at least an aromatic vinyl polymer block (A) and an aliphatic vinyl polymer block (B) as constituents, and characterized in that the content of an ion-conducting group in the aromatic vinyl polymer block (A) is 1.5 to 3.0 groups per repeating unit and the rubber polymer block (B) has no ion-conducting group; and a polymer electrolyte film, a film-electrode assembly and a solid polymer fuel cell, each of which is produced using the polymer electrolyte.

Description

高分子電解質、高分子電解質膜、膜－電極接合体及び固体高分子型燃料電池Polymer electrolyte, polymer electrolyte membrane, membrane-electrode assembly, and solid polymer fuel cell
　本発明は、低湿度下でのイオン伝導性に優れ、かつ、水による膨潤が少ない高分子電解質、該高分子電解質からなる高分子電解質膜、ならびに該高分子電解質膜を使用した膜－電極接合体及び固体高分子型燃料電池に関する。 The present invention relates to a polymer electrolyte excellent in ion conductivity under low humidity and less swollen by water, a polymer electrolyte membrane composed of the polymer electrolyte, and a membrane-electrode junction using the polymer electrolyte membrane And a polymer electrolyte fuel cell.
　近年、燃料電池技術は、エネルギー・環境問題の抜本的解決策として、さらには将来の水素エネルギー時代の中心的エネルギー変換システムとして、柱の１つに数えられている。特に固体高分子型燃料電池（ＰＥＦＣ；Ｐｏｌｙｍｅｒ　Ｅｌｅｃｔｒｏｌｙｔｅ　Ｆｕｅｌ　Ｃｅｌｌ）は、小型軽量化などの観点から、電気自動車用の駆動電源や携帯機器用の電源、さらに電気と熱を同時利用する家庭据置き用の電源機器などへの適用が検討されている。また燃料として水素を用いるものは、出力、経済性などの観点から幅広い用途展開が期待されている。 In recent years, fuel cell technology has been counted as one of the pillars as a fundamental solution for energy and environmental problems, and as a central energy conversion system in the future hydrogen energy era. In particular, polymer electrolyte fuel cells (PEFCs) are used for stationary electric power sources for electric vehicles, portable devices, and households that use both electricity and heat from the viewpoint of miniaturization and weight reduction. Application to other power supply devices is under consideration. In addition, those using hydrogen as a fuel are expected to be used in a wide range of applications from the viewpoint of output and economy.
　固体高分子型燃料電池は、一般に次のように構成される。プロトン伝導性を有する高分子電解質膜の両側に、白金属の金属触媒を担持したカーボン粉末と高分子電解質からなるイオン伝導性バインダーとを含む触媒層が配置される。各触媒層の外側には、燃料ガス及び酸化剤ガスをそれぞれ通気する多孔性材料であるガス拡散層が配置される。ガス拡散層としてはカーボンペーパー、カーボンクロスなどが用いられる。触媒層とガス拡散層を一体化したものはガス拡散電極と呼ばれ、また一対のガス拡散電極をそれぞれ触媒層が高分子電解質膜と向かい合うように高分子電解質膜に接合した構造体は膜－電極接合体（ＭＥＡ；Ｍｅｍｂｒａｎｅ　Ｅｌｅｃｔｒｏｄｅ　Ａｓｓｅｍｂｌｙ）と呼ばれている。この膜－電極接合体の両側には、導電性と気密性を備えたセパレータが配置される。電極面に燃料ガス又は酸化剤ガス（例えば空気）を供給するガス流路が膜－電極接合体とセパレータの接触部分又はセパレータ内に形成されている。一方の電極（燃料極）に燃料ガスを供給し、他方の電極（酸素極）に酸素を含有する酸化剤ガス（空気など）を供給して発電する。すなわち、燃料極では燃料がイオン化されてプロトンと電子が生じ、プロトンは高分子電解質膜を透過して、電子は両電極をつなぐことによって形成される外部電気回路を移動して、それぞれ酸素極に到達し、酸化剤ガスと反応することで水が生成する。このようにして、燃料の化学エネルギーを電気エネルギーに直接変換して取り出すことができる。 A polymer electrolyte fuel cell is generally configured as follows. On both sides of the polymer electrolyte membrane having proton conductivity, a catalyst layer containing carbon powder carrying a white metal catalyst and an ion conductive binder made of a polymer electrolyte is disposed. A gas diffusion layer, which is a porous material through which fuel gas and oxidant gas are passed, is disposed outside each catalyst layer. Carbon paper, carbon cloth, or the like is used as the gas diffusion layer. A structure in which a catalyst layer and a gas diffusion layer are integrated is called a gas diffusion electrode, and a structure in which a pair of gas diffusion electrodes is bonded to a polymer electrolyte membrane so that the catalyst layer faces the polymer electrolyte membrane is a membrane- It is called an electrode assembly (MEA; Mebrane Electrode Assembly). On both sides of the membrane-electrode assembly, separators having conductivity and airtightness are disposed. A gas flow path for supplying fuel gas or oxidant gas (for example, air) to the electrode surface is formed in the contact portion of the membrane-electrode assembly and the separator or in the separator. Electric power is generated by supplying a fuel gas to one electrode (fuel electrode) and an oxidant gas (such as air) containing oxygen to the other electrode (oxygen electrode). That is, at the fuel electrode, the fuel is ionized to generate protons and electrons, the protons pass through the polymer electrolyte membrane, and the electrons move through an external electric circuit formed by connecting the two electrodes, and are respectively transferred to the oxygen electrode. Reach and react with the oxidant gas to produce water. In this way, the chemical energy of the fuel can be directly converted into electric energy and taken out.
　これらの固体高分子型燃料電池は、上記のような一般的用途では、連続運転ではなく、起動、運転、停止を繰り返す断続運転を行うのが通常である。運転時には高分子電解質膜は湿潤下にあるが、停止時には膜の湿度低下が起こる。このため、起動時に速やかに性能を発揮するために、低湿度下でも高いプロトン伝導性を有する高分子電解質膜が望まれている。 These polymer electrolyte fuel cells usually perform intermittent operation that repeats start-up, operation, and stop, instead of continuous operation, in general applications as described above. The polymer electrolyte membrane is wet during operation, but the humidity of the membrane decreases when stopped. For this reason, a polymer electrolyte membrane having high proton conductivity even under low humidity is desired in order to quickly exhibit performance at start-up.
　一般的に、固体高分子型燃料電池用の高分子電解質膜としては、化学的に安定であるという理由からパーフルオロカーボンスルホン酸系高分子であるナフィオン（Ｎａｆｉｏｎ、デュポン社の登録商標。以下同様）が用いられている。しかしながら、ナフィオンは低湿度下におけるイオン伝導性に優れている反面、長期使用時や廃棄時に分解物として環境に悪影響を及ぼすフッ素系化合物が発生する可能性がある。また、燃料透過性が高い、高価であるなどの欠点も有しているため、代替材料が求められていた。 In general, as a polymer electrolyte membrane for a polymer electrolyte fuel cell, Nafion (a registered trademark of Nafion, DuPont), which is a perfluorocarbon sulfonic acid polymer, because it is chemically stable. Is used. However, Nafion is excellent in ionic conductivity under low humidity, but there is a possibility that a fluorine-based compound that adversely affects the environment may be generated as a decomposition product during long-term use or disposal. Further, since it has drawbacks such as high fuel permeability and high cost, an alternative material has been demanded.
　そこで近年、ナフィオンなどのパーフルオロカーボンスルホン酸系高分子に代わる材料として炭化水素系材料が提案されている。具体的にはポリエーテルサルホン（ＰＥＳ）やポリエーテルエーテルケトン（ＰＥＥＫ）に代表されるエンジニアリングプラスチック系ポリマーにスルホン酸基などのイオン伝導性基を導入した材料である。 Therefore, in recent years, hydrocarbon-based materials have been proposed as alternatives to perfluorocarbon sulfonic acid-based polymers such as Nafion. Specifically, it is a material in which an ion conductive group such as a sulfonic acid group is introduced into an engineering plastic polymer represented by polyethersulfone (PES) or polyetheretherketone (PEEK).
　例えば、特許文献１にはＰＥＳのスルホン化物が提案されている。このような材料はフッ素が含まれていないため、たとえ材料の劣化が起こってもフッ素系化合物は全く発生しない。また、イオン伝導性基導入や製膜などの製造技術的課題があるものの、原料高分子自体はパーフルオロカーボンスルホン酸系高分子に比べて、価格的にも有利である。 For example, Patent Document 1 proposes a sulfonated product of PES. Since such a material does not contain fluorine, no fluorine compound is generated even if the material is deteriorated. In addition, although there are manufacturing technical problems such as introduction of an ion conductive group and film formation, the raw material polymer itself is advantageous in terms of price compared to the perfluorocarbon sulfonic acid polymer.
　しかしながらこれらエンジニアリングプラスチック系ポリマーを用いた高分子電解質はイオン伝導性基が分子内に均一に分散しているため、イオン伝導性基の密度が低くなり、高いイオン伝導性を達成することは困難である。 However, in polymer electrolytes using these engineering plastic polymers, the ion conductive groups are uniformly dispersed in the molecule, so the density of the ion conductive groups is low and it is difficult to achieve high ion conductivity. is there.
　イオン伝導性基密度の高いイオンチャンネルを形成する目的で、イオン伝導性基が導入された重合体ブロックとイオン伝導性基が導入されていない重合体ブロックを有する変性ＰＥＳのスルホン化物も提案されている（特許文献２参照）が、縮合系ポリマーであるため合成時に繰り返し単位の交換反応が起こり、ブロック構造が崩れることで、相分離構造が得られず、十分なイオンチャンネルの形成ができない。 For the purpose of forming an ion channel having a high ion conductive group density, a sulfonated product of a modified PES having a polymer block having an ion conductive group introduced therein and a polymer block having no ion conductive group introduced therein has also been proposed. However, since it is a condensation polymer, an exchange reaction of repeating units occurs at the time of synthesis and the block structure is destroyed, so that a phase separation structure cannot be obtained and sufficient ion channels cannot be formed.
　一方、特許文献３記載の高分子電解質膜は芳香族ビニル系重合体ブロックと脂肪族ビニル系重合体ブロックを有するブロックポリマーからなり、これらは上記のような繰り返し単位の交換反応は起きないのでブロック構造は保持される。したがって、ブロックポリマー特有の相分離構造によってイオンチャンネルを形成することができる。 On the other hand, the polymer electrolyte membrane described in Patent Document 3 is composed of a block polymer having an aromatic vinyl polymer block and an aliphatic vinyl polymer block, which does not cause the above-described repeating unit exchange reaction. The structure is retained. Therefore, ion channels can be formed by the phase separation structure unique to the block polymer.
特開平１０－０４５９１３号公報Japanese Patent Laid-Open No. 10-045913 特開平１３－２５０５６７号公報Japanese Patent Laid-Open No. 13-250567 特開２００６－２１０３２６号公報JP 2006-210326 A
　しかしながら芳香族ビニル系重合体ブロックと脂肪族ビニル系重合体ブロックを有するブロックポリマーからなる高分子電解質膜は、低湿度状態では性能が不十分であり、イオン交換容量を高くしても性能には限界があった。したがって、低湿度状態で十分なイオン伝導性が確保できないのが実態であった。
　また、該高分子電解質膜を固体高分子型燃料電池に用いる場合には、固体高分子型燃料電池の発電中に高分子電解質膜と接する水による膨潤が少ないという特性も望まれる。高分子電解質膜が膨潤により変形すると、膜－電極接合体において、高分子電解質膜の電極からの剥離などが起こりやすくなる。また、前述した固体高分子型燃料電池の断続運転において、高分子電解質膜の著しい形状変化、ひいては破壊などが生じ、長期耐久性に悪影響を及ぼす可能性がある。 However, the polymer electrolyte membrane composed of a block polymer having an aromatic vinyl polymer block and an aliphatic vinyl polymer block has insufficient performance in a low humidity state. There was a limit. Therefore, the actual situation is that sufficient ion conductivity cannot be secured in a low humidity state.
In addition, when the polymer electrolyte membrane is used in a solid polymer fuel cell, it is desired that the polymer electrolyte membrane is less swelled by water in contact with the polymer electrolyte membrane during power generation of the polymer electrolyte fuel cell. When the polymer electrolyte membrane is deformed by swelling, peeling of the polymer electrolyte membrane from the electrode tends to occur in the membrane-electrode assembly. Further, in the intermittent operation of the above-described solid polymer fuel cell, a significant change in the shape of the polymer electrolyte membrane, and hence breakdown, may occur, which may adversely affect long-term durability.
　本発明者らは上記課題を解決すべく鋭意検討を行った結果、少なくとも芳香族ビニル系重合体ブロック（Ａ）と脂肪族ビニル系重合体ブロック（Ｂ）とを構成成分とするブロック共重合体であって、前記芳香族ビニル系重合体ブロック（Ａ）における繰り返し単位あたりのイオン伝導性基含有量が１．５～３．０個であって、前記脂肪族ビニル系重合体ブロック（Ｂ）がイオン伝導性基を有しないことを特徴とする高分子電解質を提供することで上記課題を解決できることを見出し、本発明を完成した。 As a result of intensive studies aimed at solving the above-mentioned problems, the present inventors have found that a block copolymer comprising at least an aromatic vinyl polymer block (A) and an aliphatic vinyl polymer block (B) as constituent components. The aromatic vinyl polymer block (A) has an ion conductive group content per repeating unit of 1.5 to 3.0, and the aliphatic vinyl polymer block (B) Has found that the above-mentioned problems can be solved by providing a polymer electrolyte characterized by not having an ion conductive group.
　すなわち、請求項１に記載の発明は、
少なくとも芳香族ビニル系重合体ブロック（Ａ）と脂肪族ビニル系重合体ブロック（Ｂ）とを構成成分とするブロック共重合体からなる高分子電解質であって、前記芳香族ビニル系重合体ブロック（Ａ）における繰り返し単位あたりのイオン伝導性基含有量が１．５～３．０個であって、前記脂肪族ビニル系重合体ブロック（Ｂ）がイオン伝導性基を有しないことを特徴とする高分子電解質に関する。 That is, the invention described in claim 1
A polymer electrolyte comprising a block copolymer having at least an aromatic vinyl polymer block (A) and an aliphatic vinyl polymer block (B) as constituent components, wherein the aromatic vinyl polymer block ( The ion conductive group content per repeating unit in A) is 1.5 to 3.0, and the aliphatic vinyl polymer block (B) does not have an ion conductive group. The present invention relates to a polymer electrolyte.
　また請求項２に記載の発明は、
前記芳香族ビニル系重合体ブロック（Ａ）が前記高分子電解質の５～５０重量％を占めることを特徴とする請求項１に記載の高分子電解質に関する。 The invention according to claim 2
2. The polymer electrolyte according to claim 1, wherein the aromatic vinyl polymer block (A) accounts for 5 to 50% by weight of the polymer electrolyte.
　また請求項３に記載の発明は、
前記芳香族ビニル系重合体ブロック（Ａ）１ｇあたりのイオン伝導性基含有量が４．８ｍｅｑ／ｇ以上であることを特徴とする請求項１に記載の高分子電解質に関する。 The invention according to claim 3
2. The polymer electrolyte according to claim 1, wherein the ion conductive group content per 1 g of the aromatic vinyl polymer block (A) is 4.8 meq / g or more.
　また請求項４に記載の発明は、
前記脂肪族ビニル系重合体ブロック（Ｂ）が、炭素数２～８のアルケン単位、炭素数５～８のシクロアルケン単位、炭素数７～１０のビニルシクロアルカン単位、炭素数７～１０のビニルシクロアルケン単位、炭素数４～８の共役ジエン単位及び炭素数５～８の共役シクロアルカジエン単位からなる群より選ばれる少なくとも１種の繰り返し単位を主成分とするゴム状重合体ブロックであることを特徴とする請求項１に記載の高分子電解質に関する。 The invention according to claim 4
The aliphatic vinyl polymer block (B) is an alkene unit having 2 to 8 carbon atoms, a cycloalkene unit having 5 to 8 carbon atoms, a vinyl cycloalkane unit having 7 to 10 carbon atoms, or a vinyl having 7 to 10 carbon atoms. It is a rubbery polymer block containing as a main component at least one repeating unit selected from the group consisting of a cycloalkene unit, a conjugated diene unit having 4 to 8 carbon atoms, and a conjugated cycloalkadiene unit having 5 to 8 carbon atoms. The polymer electrolyte according to claim 1.
　また請求項５に記載の発明は、
前記イオン伝導性基がプロトン伝導性基であることを特徴とする請求項１に記載の高分子電解質に関する。 The invention according to claim 5
The polymer electrolyte according to claim 1, wherein the ion conductive group is a proton conductive group.
　また請求項６に記載の発明は、
主としてイオン伝導性基を有しない芳香族ビニル系化合物単位を繰り返し単位とする芳香族ビニル系重合体ブロック（Ｃ）を構成成分として２０～６０重量％含むことを特徴とする請求項１に記載の高分子電解質に関する。 The invention according to claim 6
The aromatic vinyl polymer block (C) mainly comprising an aromatic vinyl compound unit having no ion conductive group as a repeating unit is contained as a constituent component in an amount of 20 to 60% by weight. The present invention relates to a polymer electrolyte.
　また請求項７に記載の発明は、
前記芳香族ビニル系重合体ブロック（Ｃ）の主たる繰り返し単位である前記芳香族ビニル系化合物単位は１～３個の炭素数１～８の炭化水素基を芳香環上に有する置換芳香族ビニル系化合物単位であることを特徴とする請求項６に記載の高分子電解質に関する。 The invention according to claim 7 provides
The aromatic vinyl compound unit, which is the main repeating unit of the aromatic vinyl polymer block (C), is a substituted aromatic vinyl compound having 1 to 3 C 1-8 hydrocarbon groups on the aromatic ring. It is a compound unit, It is related with the polymer electrolyte of Claim 6.
　また請求項８に記載の発明は、
請求項１に記載の高分子電解質からなる高分子電解質膜に関する。 The invention according to claim 8 provides
The present invention relates to a polymer electrolyte membrane comprising the polymer electrolyte according to claim 1.
　また請求項９に記載の発明は、
少なくとも請求項８に記載の高分子電解質膜と電極層との複層構造である膜－電極接合体に関する。 The invention described in claim 9
The present invention relates to a membrane-electrode assembly having a multilayer structure of at least the polymer electrolyte membrane according to claim 8 and an electrode layer.
　また請求項１０に記載の発明は、
請求項９に記載の膜－電極接合体を備える固体高分子型燃料電池に関する。 The invention according to claim 10 provides
A solid polymer fuel cell comprising the membrane-electrode assembly according to claim 9.
　本発明の高分子電解質であるブロック共重合体において、芳香族ビニル系重合体ブロック（Ａ）と脂肪族ビニル系重合体ブロック（Ｂ）とはミクロ相分離を起こし、芳香族ビニル系重合体ブロック（Ａ）同士と脂肪族ビニル系重合体ブロック（Ｂ）同士とがそれぞれ集合する性質があり、芳香族ビニル系重合体ブロック（Ａ）はイオン伝導性基を有するので芳香族ビニル系重合体ブロック（Ａ）同士の集合によりイオンチャンネルが形成され、プロトン等のイオンの通り道となる。 In the block copolymer which is the polymer electrolyte of the present invention, the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) undergo microphase separation, and the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) have the property of gathering together, and since the aromatic vinyl polymer block (A) has an ion conductive group, the aromatic vinyl polymer block (A) An ion channel is formed by the aggregation of each other, and becomes a path for ions such as protons.
　なおここで、「ミクロ相分離」とは微視的な意味での相分離を意味し、より詳しくは形成されるドメインサイズが可視光の波長（３８００～７８００Å）以下である相分離を意味するものとする。 Here, “microphase separation” means phase separation in a microscopic sense, and more specifically, means phase separation in which the formed domain size is less than or equal to the wavelength of visible light (3800 to 7800 mm). Shall.
　前記芳香族ビニル系重合体ブロック（Ａ）における繰り返し単位あたりのイオン伝導性基含有量が１．５～３．０個であって、前記脂肪族ビニル系重合体ブロック（Ｂ）がイオン伝導性基を有しないことで、該イオンチャンネルは高密度でイオン伝導性基が存在する。 The aromatic vinyl polymer block (A) has an ion conductive group content of 1.5 to 3.0 per repeating unit, and the aliphatic vinyl polymer block (B) has an ion conductivity. By not having groups, the ion channel is dense and ion-conducting groups are present.
　この結果、本発明の高分子電解質からなる高分子電解質膜は、相分離が顕著に起こり、イオン伝導性が高くなり、特に低湿度下における高いイオン伝導性を有し、該高分子電解質膜を含んでなる膜－電極接合体は固体高分子型燃料電池に用いることで、低湿度下においても高い出力特性を得ることが可能であり、また水による膨潤も少なく、電極との接合性にも優れる。 As a result, in the polymer electrolyte membrane comprising the polymer electrolyte of the present invention, phase separation occurs remarkably and ion conductivity becomes high, and particularly has high ion conductivity under low humidity. By using the membrane-electrode assembly comprising the polymer electrolyte fuel cell, it is possible to obtain high output characteristics even under a low humidity, and there is little swelling due to water, and the bonding property to the electrode is also improved. Excellent.
　以下、本発明について詳細に説明する。
　本発明の高分子電解質を構成するブロック共重合体は、芳香族ビニル系重合体ブロック（Ａ）を構成成分とする。該芳香族ビニル系重合体ブロック（Ａ）は芳香族ビニル系化合物単位を主たる繰り返し単位とし、かつ、繰り返し単位あたりのイオン伝導性基含有量が１．５～３．０個であるが、高分子電解質の要求性能等によって適宜選択される。イオン伝導性の観点からは１．７個以上であることが好ましく、スルホン酸基の導入のしやすさの観点からは１．５個～２．０個であることが好ましい。 Hereinafter, the present invention will be described in detail.
The block copolymer constituting the polymer electrolyte of the present invention contains an aromatic vinyl polymer block (A) as a constituent component. The aromatic vinyl polymer block (A) has an aromatic vinyl compound unit as a main repeating unit and an ion conductive group content per repeating unit of 1.5 to 3.0. It is appropriately selected depending on the required performance of the molecular electrolyte. From the viewpoint of ion conductivity, it is preferably 1.7 or more, and from the viewpoint of ease of introduction of the sulfonic acid group, it is preferably 1.5 to 2.0.
　ここで、芳香族ビニル系重合体ブロック（Ａ）の繰り返し単位である芳香族ビニル系化合物単位とは、芳香族ビニル系化合物の重合によって形成できる構造である。該芳香族ビニル系化合物とは、少なくとも１つの芳香環と、少なくとも一つの芳香環上の炭素原子に直結する付加重合性炭素二重結合を含む官能基を少なくとも１つ有する化合物を指す。 Here, the aromatic vinyl compound unit that is a repeating unit of the aromatic vinyl polymer block (A) is a structure that can be formed by polymerization of an aromatic vinyl compound. The aromatic vinyl compound refers to a compound having at least one functional group containing at least one aromatic ring and an addition polymerizable carbon double bond directly bonded to a carbon atom on at least one aromatic ring.
　例えばベンゼン環などの芳香環上の水素をビニル基、１－アルキルエテニル基（例えばイソプロペニル基）、１－アリールエテニル基などの置換基で置換した化合物が挙げられる。具体的にはスチレン、α－メチルスチレン、ジフェニルエチレンが挙げられる。 Examples thereof include compounds in which hydrogen on an aromatic ring such as a benzene ring is substituted with a substituent such as a vinyl group, a 1-alkylethenyl group (eg, an isopropenyl group), or a 1-arylethenyl group. Specific examples include styrene, α-methylstyrene, and diphenylethylene.
　また、芳香族ビニル系重合体ブロック（Ａ）の繰り返し単位である芳香族ビニル系化合物単位を形成できる芳香族ビニル系化合物は芳香環を形成する炭素原子を１０以上有することが好ましい。例えば、ベンゼン環などの炭素数１０以下の芳香環を複数有する化合物、該炭素数１０以下の芳香環が縮合した縮合環を有する化合物が挙げられる。 The aromatic vinyl compound that can form an aromatic vinyl compound unit that is a repeating unit of the aromatic vinyl polymer block (A) preferably has 10 or more carbon atoms that form an aromatic ring. For example, a compound having a plurality of aromatic rings having 10 or less carbon atoms such as a benzene ring and a compound having a condensed ring obtained by condensing the aromatic rings having 10 or less carbon atoms can be given.
　ベンゼン環を複数有する芳香族ビニル系化合物の例としては、ビニルビフェニル、ビニルターフェニル、フェノキシスチレン、ジフェニルエチレンが挙げられる。 Examples of the aromatic vinyl compound having a plurality of benzene rings include vinyl biphenyl, vinyl terphenyl, phenoxystyrene, and diphenylethylene.
　また前記縮合環としては、ナフタレン環、フェナントレン環、アントラセン環、ピレン環、クリセン環、フルオレン環が挙げられる。これら芳香族ビニル系化合物の具体例として、ビニルナフタレン、ビニルフェナントレン、ビニルアントラセン、ビニルピレン、ビニルクリセンビニルフルオレンが挙げられる。 In addition, examples of the condensed ring include a naphthalene ring, a phenanthrene ring, an anthracene ring, a pyrene ring, a chrysene ring, and a fluorene ring. Specific examples of these aromatic vinyl compounds include vinyl naphthalene, vinyl phenanthrene, vinyl anthracene, vinyl pyrene, and vinyl chrysene vinyl fluorene.
　中でも繰り返し単位の分子量が小さく、構造がコンパクトなことからイオンチャンネルの高密度化に有利であるという点で、ビニルナフタレン、ビニルビフェニル、ビニルターフェニルが好ましく、イオン伝導性基の導入しやすさからビニルビフェニルがより一層好ましい。 Of these, vinyl naphthalene, vinyl biphenyl, and vinyl terphenyl are preferred because the molecular weight of the repeating unit is small and the structure is compact, which is advantageous for increasing the density of the ion channel. Vinyl biphenyl is even more preferred.
　芳香族ビニル系化合物単位の平均分子量は、４００以下であることが好ましく、３００以下であることが好ましく、２００以下であることがより好ましい。該平均分子量は繰り返し単位の芳香族ビニル化合物単位がイオン伝導性基を有する場合は芳香族ビニル系重合体ブロックの全てのイオン伝導性基を水素に置換した重合体ブロック（すなわち対応するイオン伝導性基を有しない重合体ブロック）を想定して算出する。繰り返し単位の平均分子量が大きすぎるとイオンチャンネルの密度が低下する場合があり、好ましくない。 The average molecular weight of the aromatic vinyl compound unit is preferably 400 or less, preferably 300 or less, and more preferably 200 or less. When the aromatic vinyl compound unit of the repeating unit has an ion conductive group, the average molecular weight is a polymer block obtained by substituting all ion conductive groups of the aromatic vinyl polymer block with hydrogen (that is, the corresponding ion conductivity). It is calculated assuming a polymer block having no group. If the average molecular weight of the repeating unit is too large, the density of the ion channel may decrease, which is not preferable.
　芳香族ビニル系化合物を重合して芳香族ビニル系重合体ブロック（Ａ）とする場合、芳香族ビニル系化合物は、２種以上組み合わせて使用してもよい。これらの２種以上を共重合させる場合の形態はランダム共重合でもブロック共重合でもグラフト共重合でもテーパード共重合でもよい。 When the aromatic vinyl compound is polymerized into the aromatic vinyl polymer block (A), two or more aromatic vinyl compounds may be used in combination. The form in the case of copolymerizing two or more of these may be random copolymerization, block copolymerization, graft copolymerization or tapered copolymerization.
　また、芳香族ビニル系重合体ブロック（Ａ）は発明の効果を損なわない範囲内で１種もしくは複数の他の単量体単位を含んでいてもよい。かかる他の単量体単位を構成できる単量体としては、例えば、炭素数４～８の共役ジエン（１，３－ブタジエン、１，３－ペンタジエン、イソプレン、１，３－ヘキサジエン、２，４－ヘキサジエン、２，３－ジメチル－１，３－ブタジエン、２－エチル－１，３－ブタジエン、１，３－ヘプタジエン、１，４－ヘプタジエン、３，５－ヘプタジエン等）、炭素数２～８のアルケン（エチレン、プロピレン、１－ブテン、２－ブテン、イソブテン、１－ペンテン、２－ペンテン、１－ヘキセン、２－ヘキセン、１－ヘプテン、２－ヘプテン、１－オクテン、２－オクテン等）、（メタ）アクリル酸エステル（（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ブチル等）、ビニルエステル（酢酸ビニル、プロピオン酸ビニル、酪酸ビニル、ピバリン酸ビニル等）、ビニルエーテル（メチルビニルエーテル、イソブチルビニルエーテル等）等が挙げられる。上記他の単量体との共重合形態はランダム共重合であることが望ましい。 In addition, the aromatic vinyl polymer block (A) may contain one or more other monomer units as long as the effects of the invention are not impaired. Examples of monomers that can constitute such other monomer units include conjugated dienes having 4 to 8 carbon atoms (1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 2,4 -Hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-heptadiene, 1,4-heptadiene, 3,5-heptadiene, etc.), carbon number 2-8 Alkenes (ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-heptene, 2-heptene, 1-octene, 2-octene, etc.) , (Meth) acrylate esters (methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, etc.), vinyl esters (vinyl acetate, propion) Vinyl, vinyl butyrate, vinyl pivalate, etc.), vinyl ethers (methyl vinyl ether, isobutyl vinyl ether, etc.), and the like. The copolymerization form with the other monomer is desirably random copolymerization.
　芳香族ビニル系重合体ブロック（Ａ）が前記高分子電解質の５～５０重量％を占めることが、高分子電解質膜がイオン伝導性と耐水性を両立させる上で、好ましい。イオン伝導度の観点からは３５～５０重量％を占めることがより好ましく、耐水性の観点からは５～２５重量％を占めることがより好ましく、イオン伝導度と耐水性を両立させるためには２０～４０重量％を占めることがより好ましい。 It is preferable that the aromatic vinyl polymer block (A) occupies 5 to 50% by weight of the polymer electrolyte in order for the polymer electrolyte membrane to satisfy both ion conductivity and water resistance. From the viewpoint of ionic conductivity, it is more preferable to occupy 35 to 50% by weight, and from the viewpoint of water resistance, it is more preferable to occupy 5 to 25% by weight. To achieve both ionic conductivity and water resistance, 20% is preferable. More preferably, it accounts for ˜40% by weight.
　芳香族ビニル系重合体ブロック（Ａ）は芳香族ビニル系化合物単位を主たる繰り返し単位とすることで、脂肪族ビニル系重合体ブロック（Ｂ）とのミクロ相分離を起こす上で有利であり、この結果イオン伝導性を高めることができる。該芳香族ビニル系化合物単位が主たる繰り返し単位であるとは、芳香族ビニル系重合体ブロック（Ａ）の８０重量％を超えて占めることであり、十分なイオン伝導性を付与するために、９０重量％以上を占めることがより好ましく、９５重量％以上を占めることがより一層好ましい。８０重量％を下回ると、芳香族ビニル系重合体ブロック（Ａ）における繰り返し単位あたりのイオン伝導性基含有量が少なくなり、イオン伝導性基の密度も低下するため、本発明の効果が得られなくなる場合がある。ここで該重量割合は芳香族ビニル系重合体ブロックの全てのイオン伝導性基を水素に置換した重合体ブロック（すなわち対応するイオン伝導性基を有しない重合体ブロック）を想定して算出する。 The aromatic vinyl polymer block (A) is advantageous in causing microphase separation from the aliphatic vinyl polymer block (B) by using the aromatic vinyl compound block as a main repeating unit. As a result, ion conductivity can be increased. That the aromatic vinyl compound unit is the main repeating unit means that the aromatic vinyl polymer block (A) accounts for more than 80% by weight, and in order to impart sufficient ion conductivity, 90% It is more preferable to occupy 95% by weight or more, and even more preferably 95% by weight or more. If it is less than 80% by weight, the ion conductive group content per repeating unit in the aromatic vinyl polymer block (A) decreases, and the density of the ion conductive group also decreases, so that the effect of the present invention is obtained. It may disappear. Here, the weight ratio is calculated assuming a polymer block in which all ion conductive groups of the aromatic vinyl polymer block are substituted with hydrogen (that is, a polymer block having no corresponding ion conductive group).
　このように本発明で言う芳香族ビニル系重合体ブロック（Ａ）とは同種のモノマーが連続して主鎖を構成するものだけでなく、芳香族ビニル系化合物単位を主たる繰り返し単位とし、均一な相を形成できるものであれば含む。なお、相の観察は透過型電子顕微鏡（ＴＥＭ）で行うことができる。すなわち、高分子電解質より作製した高分子電解質膜をエポキシ樹脂で包埋した後、クライオウルトラミクロトームを用いて厚さ約９０ｎｍの超薄切片を作製し、この超薄切片を酢酸鉛で染色することで、芳香族ビニル系重合体ブロック（Ａ）を観察することができる。 As described above, the aromatic vinyl polymer block (A) referred to in the present invention is not limited to those in which the same type of monomer continuously constitutes the main chain, but the aromatic vinyl compound unit is a main repeating unit, and is uniform. Any material capable of forming a phase is included. The phase can be observed with a transmission electron microscope (TEM). In other words, after embedding a polymer electrolyte membrane made from a polymer electrolyte with an epoxy resin, an ultrathin section having a thickness of about 90 nm is prepared using a cryo-ultramicrotome, and this ultrathin section is stained with lead acetate. The aromatic vinyl polymer block (A) can be observed.
　芳香族ビニル系重合体ブロック（Ａ）１つあたりの分子量は、高分子電解質の性状、要求性能、他の重合体成分等によって適宜選択される。分子量が大きい場合、得られる高分子電解質膜の力学特性が高くなる傾向にあるが、大きすぎるとブロック共重合体の成形、製膜が困難になり、分子量が小さい場合、ミクロ相分離構造、ひいては、イオンチャンネルを形成しにくくなるため、イオン伝導性、力学特性が低下する傾向にあることから、必要性能に応じて分子量を適宜選択することが重要である。 The molecular weight per aromatic vinyl polymer block (A) is appropriately selected depending on the properties of the polymer electrolyte, required performance, other polymer components, and the like. When the molecular weight is large, the mechanical properties of the resulting polymer electrolyte membrane tend to be high, but when it is too large, it becomes difficult to form and form a block copolymer, and when the molecular weight is small, the microphase separation structure, and thus Since it is difficult to form an ion channel, ion conductivity and mechanical properties tend to be lowered. Therefore, it is important to appropriately select a molecular weight according to required performance.
　芳香族ビニル系重合体ブロック（Ａ）１つあたりの分子量は、イオン伝導性基を水素に置換した構造（すなわち対応するイオン伝導性基を有しないブロック共重合体）として計算すると標準ポリスチレン換算の数平均分子量として、通常、１，０００～１，０００，０００の間から選択され、２，０００～２５０，０００の範囲から選択されるのが好ましく、３，０００～１００，０００の間から選択されるのがより好ましく、４，０００～５０，０００の間から選択されるのがさらに好ましく、５，０００～２５，０００の間から選択されるのが特に好ましい。また、製膜時の溶液調製のしやすさ、および製膜性の観点から、５，０００～１０，０００の間から選択されるのが好ましい。 When the molecular weight per aromatic vinyl polymer block (A) is calculated as a structure in which an ion conductive group is substituted with hydrogen (that is, a block copolymer having no corresponding ion conductive group), it is calculated in terms of standard polystyrene. The number average molecular weight is usually selected from 1,000 to 1,000,000, preferably selected from the range of 2,000 to 250,000, and selected from 3,000 to 100,000. More preferably, it is selected from 4,000 to 50,000, more preferably from 5,000 to 25,000. Further, from the viewpoint of ease of solution preparation during film formation and film forming properties, it is preferably selected from 5,000 to 10,000.
　また、芳香族ビニル系重合体ブロック（Ａ）は、本発明の効果を損なわない範囲内で公知の方法により架橋されていてもよい。架橋を導入することにより、芳香族ビニル系重合体ブロック（Ａ）が形成するイオンチャンネル相が膨潤しにくくなり、乾燥時と湿潤時の力学特性（引張特性等）の変化などが更に小さくなる傾向にある。 The aromatic vinyl polymer block (A) may be crosslinked by a known method within a range not impairing the effects of the present invention. By introducing cross-linking, the ion channel phase formed by the aromatic vinyl polymer block (A) is less likely to swell, and changes in mechanical properties (such as tensile properties) between drying and wetting tend to be further reduced. It is in.
　芳香族ビニル系重合体ブロック（Ａ）１ｇあたりのイオン伝導性基のモル数（ＡブロックＩＥＣ）は、本発明の効果を発現するために、４．８ｍｅｑ／ｇ以上であることが好ましく、５．１ｍｅｑ／ｇ以上がさらに好ましく、５．６ｍｅｑ／ｇ以上であることがより一層好ましい。 The number of moles of ion conductive groups per 1 g of aromatic vinyl polymer block (A) (A block IEC) is preferably 4.8 meq / g or more in order to exhibit the effects of the present invention. .1 meq / g or more is more preferable, and 5.6 meq / g or more is even more preferable.
　芳香族ビニル系重合体ブロック（Ａ）が有するイオン伝導性基としては特に限定はなく、イオン伝導性を有する官能基を用いることが出来、アニオンおよび／またはカチオンとの親和性が高いもの、特に官能基の一部がイオンとして解離しやすいものが好適であり、例えばスルホン酸基、ホスホン酸基、カルボン酸基、４級アンモニウム塩、ピリジンの４級塩などが挙げられる。特にプロトン伝導性基または該プロトン伝導性基のプロトンを他のイオンと交換した塩はプロトン伝導性に優れ、例えばスルホン酸基、ホスホン酸基、カルボン酸基並びにそれらの塩などが挙げられる。イオン伝導性、導入しやすさ、価格などの観点からスルホン酸基及びホスホン酸基並びにそれらの塩が好適に用いられる。イオン伝導性基の種類や濃度を適宜選択することでイオン交換容量を調節することができる。 The ion conductive group possessed by the aromatic vinyl polymer block (A) is not particularly limited, and a functional group having ion conductivity can be used, particularly those having high affinity with anions and / or cations, Those in which some of the functional groups are easily dissociated as ions are suitable, and examples thereof include sulfonic acid groups, phosphonic acid groups, carboxylic acid groups, quaternary ammonium salts, and quaternary salts of pyridine. In particular, a proton conductive group or a salt obtained by exchanging protons of the proton conductive group with other ions is excellent in proton conductivity, and examples thereof include sulfonic acid groups, phosphonic acid groups, carboxylic acid groups, and salts thereof. From the viewpoints of ion conductivity, ease of introduction, cost, etc., sulfonic acid groups and phosphonic acid groups and their salts are preferably used. The ion exchange capacity can be adjusted by appropriately selecting the type and concentration of the ion conductive group.
　芳香族ビニル系重合体ブロック（Ａ）中におけるイオン伝導性基の位置については特に制限はないが、イオン伝導性基導入の容易さから、芳香族ビニル系化合物単位の芳香環上に導入するのが好ましい。 The position of the ion conductive group in the aromatic vinyl polymer block (A) is not particularly limited, but it is introduced onto the aromatic ring of the aromatic vinyl compound unit for ease of introduction of the ion conductive group. Is preferred.
　また、本発明の高分子電解質を構成するブロック共重合体は、脂肪族ビニル系重合体ブロック（Ｂ）を構成成分とする。該脂肪族ビニル系重合体ブロック（Ｂ）は脂肪族ビニル系化合物単位を主たる繰り返し単位とし、かつ、イオン伝導性基を有しない。 Also, the block copolymer constituting the polymer electrolyte of the present invention comprises an aliphatic vinyl polymer block (B) as a constituent component. The aliphatic vinyl polymer block (B) has an aliphatic vinyl compound unit as a main repeating unit and does not have an ion conductive group.
　ここで、脂肪族ビニル系重合体ブロック（Ｂ）の主たる繰り返し単位である脂肪族ビニル系化合物単位とは、脂肪族ビニル系化合物の重合によって形成できる構造である。該脂肪族ビニル系化合物とは、少なくとも一つの芳香環を構成しない炭素原子に直結する付加重合性炭素二重結合を含む官能基を少なくとも１つ有する化合物を指す。 Here, the aliphatic vinyl compound unit, which is the main repeating unit of the aliphatic vinyl polymer block (B), is a structure that can be formed by polymerization of an aliphatic vinyl compound. The aliphatic vinyl compound refers to a compound having at least one functional group containing an addition polymerizable carbon double bond directly bonded to a carbon atom that does not constitute at least one aromatic ring.
　前記脂肪族ビニル系化合物単位としては、炭素数２～８のアルケン単位、炭素数５～８のシクロアルケン単位、炭素数７～１０のビニルシクロアルカン単位、炭素数７～１０のビニルシクロアルケン単位、炭素数４～８の共役ジエン単位及び炭素数５～８の共役シクロアルカジエン単位が挙げられる。これらの群から選ばれる繰り返し単位は単独または２種以上組み合わせて用いてもよい。２種以上を重合（共重合）させる場合の形態はランダム共重合でもブロック共重合でもグラフト共重合でもテーパード共重合でもよい。また、重合に供する単量体が炭素－炭素二重結合を複数有する場合にはそのいずれが重合に用いられてもよく、共役ジエンの場合には複数種の重合可能な位置（例えば１，３－ジエンの１，２－結合、３，４－結合、１，４－結合による重合）があるが、特に限定はなく、その割合（例えば１，２－結合と１，４－結合との割合）にも特に制限はない。 Examples of the aliphatic vinyl compound unit include alkene units having 2 to 8 carbon atoms, cycloalkene units having 5 to 8 carbon atoms, vinylcycloalkane units having 7 to 10 carbon atoms, and vinylcycloalkene units having 7 to 10 carbon atoms. And conjugated diene units having 4 to 8 carbon atoms and conjugated cycloalkadiene units having 5 to 8 carbon atoms. You may use the repeating unit chosen from these groups individually or in combination of 2 or more types. The form in the case of polymerizing (copolymerizing) two or more kinds may be random copolymerization, block copolymerization, graft copolymerization or tapered copolymerization. Further, when the monomer to be polymerized has a plurality of carbon-carbon double bonds, any of them may be used for the polymerization. In the case of a conjugated diene, a plurality of kinds of polymerizable positions (for example, 1, 3 -Diene 1,2-bond, 3,4-bond, 1,4-bond polymerization), but there is no particular limitation, and the ratio (for example, ratio of 1,2-bond to 1,4-bond) ) Is not particularly limited.
　このような単量体単位を構成する単量体のうち、炭素数２～８のアルケンとしては、エチレン、プロピレン、１－ブテン、２－ブテン、イソブテン、１－ペンテン、２－ペンテン、１－ヘキセン、２－ヘキセン、１－ヘプテン、２－ヘプテン、１－オクテン、２－オクテンなど、炭素数５～８のシクロアルケンとしてはシクロペンテン、シクロヘキセン、シクロヘプテンおよびシクロオクテンなど、炭素数７～１０のビニルシクロアルカンとしてはビニルシクロペンタン、ビニルシクロヘキサン、ビニルシクロヘプタン、ビニルシクロオクタンなど、炭素数７～１０のビニルシクロアルケンとしてはビニルシクロペンテン、ビニルシクロヘキセン、ビニルシクロヘプテン、ビニルシクロオクテンなど、炭素数４～８の共役ジエンとしては１，３－ブタジエン、１，３－ペンタジエン、イソプレン、１，３－ヘキサジエン、２，４－ヘキサジエン、２，３－ジメチル－１，３－ブタジエン、２－エチル－１，３－ブタジエン、１，３－ヘプタジエン、２，４－ヘプタジエンなど、炭素数５～８の共役シクロアルカジエンとしては、シクロペンタジエン、１，３－シクロヘキサジエンなどがそれぞれ挙げられる。これら単量体は単独で用いてもよく、２種以上を併用してもよい。 Among these monomers constituting the monomer unit, the alkene having 2 to 8 carbon atoms includes ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 1- Cycloalkene having 5 to 8 carbon atoms such as hexene, 2-hexene, 1-heptene, 2-heptene, 1-octene, 2-octene, etc., and vinyl having 7 to 10 carbon atoms such as cyclopentene, cyclohexene, cycloheptene and cyclooctene Examples of cycloalkanes include vinylcyclopentane, vinylcyclohexane, vinylcycloheptane, and vinylcyclooctane. Examples of vinylcycloalkene having 7 to 10 carbon atoms include vinylcyclopentene, vinylcyclohexene, vinylcycloheptene, and vinylcyclooctene. 1 to 8 conjugated dienes 3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 2,4-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3- Examples of the conjugated cycloalkadiene having 5 to 8 carbon atoms such as heptadiene and 2,4-heptadiene include cyclopentadiene and 1,3-cyclohexadiene. These monomers may be used independently and may use 2 or more types together.
　脂肪族ビニル系重合体ブロック（Ｂ）を形成するための単量体が、ビニルシクロアルケンや共役ジエンや共役シクロアルカジエンである場合のように炭素－炭素二重結合を複数有している場合には、重合後の繰り返し単位は炭素－炭素二重結合を有するが、更にこれを飽和させた構造を繰り返し単位とすることもできる。これは上記単量体を重合させた場合は残留した炭素－炭素二重結合を水素添加することで得られる。本発明の高分子電解質膜を用いた膜－電極接合体の発電性能、耐熱劣化性の向上などの観点から、かかる炭素－炭素二重結合はその３０モル％以上が水素添加された構造であることが好ましく、５０モル％以上が水素添加された構造であることがより好ましく、８０モル％以上が水素添加された構造であることがより一層好ましい。炭素－炭素二重結合の存在率（または水素添加率）は、一般に用いられている方法、例えば、ヨウ素価測定法、1Ｈ－ＮＭＲ測定等によって算出することができる。 When the monomer for forming the aliphatic vinyl polymer block (B) has a plurality of carbon-carbon double bonds as in the case of vinylcycloalkene, conjugated diene or conjugated cycloalkadiene In addition, although the repeating unit after polymerization has a carbon-carbon double bond, a structure in which this is further saturated can be used as the repeating unit. This can be obtained by hydrogenating the remaining carbon-carbon double bond when the monomer is polymerized. From the viewpoint of improving the power generation performance and heat deterioration resistance of the membrane-electrode assembly using the polymer electrolyte membrane of the present invention, such a carbon-carbon double bond has a structure in which 30 mol% or more thereof is hydrogenated. It is more preferable that a structure in which 50 mol% or more is hydrogenated is more preferable, and a structure in which 80 mol% or more is hydrogenated is even more preferable. The abundance (or hydrogenation rate) of the carbon-carbon double bond can be calculated by a commonly used method, for example, iodine value measurement method, 1 H-NMR measurement or the like.
　脂肪族ビニル系重合体ブロック（Ｂ）は、得られるブロック共重合体に、弾力性ひいては膜－電極接合体や固体高分子型燃料電池の作製にあたって良好な成形性を与える観点から、炭素数２～８のアルケン単位、炭素数５～８のシクロアルケン単位、炭素数７～１０のビニルシクロアルケン単位、炭素数４～８の共役ジエン単位及び炭素数５～８の共役シクロアルカジエン単位よりなる群から選ばれる少なくとも一種の繰り返し単位からなる重合体ブロックであることが好ましく、炭素数３～６のアルケン単位、炭素数４～６の共役ジエン単位から選ばれる少なくとも１種の繰り返し単位からなる重合体ブロックであることがより好ましく、炭素数４～５のアルケン単位、炭素数４～５の共役ジエン単位から選ばれる少なくとも１種の繰り返し単位からなる重合体ブロックであることがより一層好ましい。
　上記で、アルケン単位として好ましいのはイソブテン単位、１，３－ブタジエン単位の二重結合を飽和した構造単位（１－ブテン単位、２－ブテン単位）、イソプレン単位の二重結合を飽和した構造単位（２－メチル－１－ブテン単位、３－メチル－１－ブテン単位、２－メチル－２－ブテン単位）であり、特に柔軟性の高さから１，３－ブタジエン単位の二重結合を飽和した構造単位（１－ブテン単位、２－ブテン単位）、イソプレン単位の二重結合を飽和した構造単位（２－メチル－１－ブテン単位、３－メチル－１－ブテン単位、２－メチル－２－ブテン単位）が、最も好ましい。共役ジエン単位として最も好ましいのは１，３－ブタジエン単位、イソプレン単位である。 The aliphatic vinyl polymer block (B) has a carbon number of 2 from the viewpoint of giving the resulting block copolymer elasticity and, in turn, good moldability in the production of a membrane-electrode assembly and a polymer electrolyte fuel cell. It consists of alkene units of ˜8, cycloalkene units of 5 to 8 carbon atoms, vinylcycloalkene units of 7 to 10 carbon atoms, conjugated diene units of 4 to 8 carbon atoms and conjugated cycloalkadiene units of 5 to 8 carbon atoms. It is preferably a polymer block composed of at least one repeating unit selected from the group, and a polymer block composed of at least one repeating unit selected from alkene units having 3 to 6 carbon atoms and conjugated diene units having 4 to 6 carbon atoms. It is more preferably a combined block, and at least one repeating unit selected from alkene units having 4 to 5 carbon atoms and conjugated diene units having 4 to 5 carbon atoms. It is more preferably a polymer block comprising a unit.
In the above, preferred as the alkene unit are structural units saturated with double bonds of isobutene units, 1,3-butadiene units (1-butene units, 2-butene units), and structural units saturated with double bonds of isoprene units. (2-methyl-1-butene unit, 3-methyl-1-butene unit, 2-methyl-2-butene unit), especially saturated double bond of 1,3-butadiene unit due to its high flexibility Structural units (1-butene units, 2-butene units), structural units saturated with double bonds of isoprene units (2-methyl-1-butene units, 3-methyl-1-butene units, 2-methyl-2 -Butene units) are most preferred. Most preferred conjugated diene units are 1,3-butadiene units and isoprene units.
　脂肪族ビニル系重合体ブロック（Ｂ）は脂肪族ビニル系化合物単位が主たる繰り返し単位であり、すなわち、脂肪族ビニル系化合物単位が５０重量％を超えており、７０重量％を超えていることが好ましく、９０重量％を超えていることがより好ましい。 In the aliphatic vinyl polymer block (B), the aliphatic vinyl compound unit is the main repeating unit, that is, the aliphatic vinyl compound unit exceeds 50% by weight and exceeds 70% by weight. Preferably, it exceeds 90% by weight.
　脂肪族ビニル系重合体ブロック（Ｂ）は、上記繰り返し単位以外に、ブロック共重合体に弾力性を与えるという脂肪族ビニル系重合体ブロック（Ｂ）の目的を損なわない範囲で他の繰り返し単位、例えばスチレン単位、ビニルナフタレン単位等の芳香族ビニル系化合物単位、塩化ビニル単位等のハロゲン含有ビニル化合物単位、炭素数１～１２の側鎖を有するアクリル酸エステル単位、ならびに炭素数１～１２の側鎖を有するメタクリル酸エステル単位等を含んでいてもよい。この場合上記単量体と他の単量体との共重合形態はランダム共重合であることが望ましい。かかる他の単量体の使用量は、脂肪族ビニル系重合体ブロック（Ｂ）の５０重量％未満であり、３０重量％未満であるのがより好ましく、１０重量％未満であるのがより一層好ましい。 In addition to the above repeating units, the aliphatic vinyl polymer block (B) has other repeating units as long as the purpose of the aliphatic vinyl polymer block (B) to give elasticity to the block copolymer is not impaired. For example, aromatic vinyl compound units such as styrene units and vinylnaphthalene units, halogen-containing vinyl compound units such as vinyl chloride units, acrylate ester units having 1 to 12 carbon side chains, and sides having 1 to 12 carbon atoms It may contain a methacrylic ester unit having a chain. In this case, it is desirable that the copolymerization form of the monomer and the other monomer is random copolymerization. The amount of such other monomer used is less than 50% by weight of the aliphatic vinyl polymer block (B), more preferably less than 30% by weight, and even more preferably less than 10% by weight. preferable.
　脂肪族ビニル系重合体ブロック（Ｂ）をゴム状重合体ブロックとした場合、ブロック共重合体が全体として弾力性を帯びかつ柔軟になり、膜－電極接合体や固体高分子型燃料電池の作製に当たって成形性（組立性、接合性、締付性など）等が改善される。ここでいうゴム状重合体ブロックとはガラス転移点あるいは軟化点が３０℃以下、好ましくは２０℃以下、より好ましくは１０℃以下の重合体ブロックを意味する。 When the aliphatic vinyl polymer block (B) is a rubber-like polymer block, the block copolymer becomes elastic and flexible as a whole, and a membrane-electrode assembly and a polymer electrolyte fuel cell are produced. In this case, formability (assembling property, joining property, tightening property, etc.) and the like are improved. The rubber-like polymer block here means a polymer block having a glass transition point or softening point of 30 ° C. or lower, preferably 20 ° C. or lower, more preferably 10 ° C. or lower.
　重合体ブロック（Ｂ）をゴム状重合体ブロックとする上では、炭素数２～８のアルケン単位、炭素数５～８のシクロアルケン単位、炭素数７～１０のビニルシクロアルカン単位、炭素数７～１０のビニルシクロアルケン単位、炭素数４～８の共役ジエン単位及び炭素数５～８の共役シクロアルカジエン単位からなる群より選ばれる少なくとも１種の繰り返し単位を主成分とすることが好ましく、炭素数２～５のアルケン単位、炭素数４～５の共役ジエン単位からなる群より選ばれる少なくとも１種の繰り返し単位を主成分とすることがより好ましい。 When the polymer block (B) is a rubbery polymer block, the alkene unit having 2 to 8 carbon atoms, the cycloalkene unit having 5 to 8 carbon atoms, the vinylcycloalkane unit having 7 to 10 carbon atoms, the carbon number 7 Preferably, the main component is at least one repeating unit selected from the group consisting of a vinylcycloalkene unit having 10 to 10, a conjugated diene unit having 4 to 8 carbon atoms, and a conjugated cycloalkadiene unit having 5 to 8 carbon atoms, More preferably, the main component is at least one repeating unit selected from the group consisting of alkene units having 2 to 5 carbon atoms and conjugated diene units having 4 to 5 carbon atoms.
　脂肪族ビニル系重合体ブロック（Ｂ）１つあたりの分子量は、高分子電解質の性状、要求性能、他の重合体成分等によって適宜選択される。標準ポリスチレン換算の数平均分子量として、通常、１，０００～１，０００，０００の間から選択され、５，０００～５００，０００の範囲から選択されるのが好ましく、１０，０００～２００，０００の間から選択されるのがより好ましい。また、脂肪族ビニル系重合体ブロック（Ｂ）をゴム状重合体ブロックとした場合、成形性、および柔軟性を両立する観点から、１５，０００～１２０，０００の間から選択されるのが特に好ましい。 The molecular weight per aliphatic vinyl polymer block (B) is appropriately selected depending on the properties of the polymer electrolyte, required performance, other polymer components, and the like. The number average molecular weight in terms of standard polystyrene is usually selected from 1,000 to 1,000,000, preferably from 5,000 to 500,000, and preferably 10,000 to 200,000. It is more preferable to select between. When the aliphatic vinyl polymer block (B) is a rubbery polymer block, it is particularly selected from 15,000 to 120,000 from the viewpoint of achieving both moldability and flexibility. preferable.
　脂肪族ビニル系重合体ブロック（Ｂ）はイオン伝導性基を有さない。ここでイオン伝導性基を有さないとは実質的にイオン伝導性を有さない程度であることを意味しており、芳香族ビニル系重合体ブロック（Ａ）とのミクロ相分離性を高める上では、例えば繰り返し単位あたりのイオン伝導性基含有量が０．１以下であることが好ましく、０．０１以下であることがより好ましく、全く有さないことが最も好ましい。但し製造上、繰り返し単位あたり０．００１～０．０５程度のイオン伝導性基を含有する方が有利な場合がある。 The aliphatic vinyl polymer block (B) does not have an ion conductive group. Here, having no ion-conducting group means that the ion-conducting group is not substantially ion-conducting, and enhances microphase separation from the aromatic vinyl polymer block (A). Above, for example, the ion conductive group content per repeating unit is preferably 0.1 or less, more preferably 0.01 or less, and most preferably not at all. However, in production, it may be advantageous to contain about 0.001 to 0.05 ion conductive groups per repeating unit.
　脂肪族ビニル系重合体ブロック（Ｂ）は疎水性であることで芳香族ビニル系重合体ブロック（Ａ）との相分離が良好に起こるので好ましい。例えば水酸基、アミノ基などの親水性基を実質的に有さないことが好ましく、エステル基などの極性基を実質的に有さないことも好ましい。 Since the aliphatic vinyl polymer block (B) is hydrophobic, phase separation with the aromatic vinyl polymer block (A) occurs favorably. For example, it is preferably substantially free of hydrophilic groups such as hydroxyl groups and amino groups, and it is also preferred that substantially no polar groups such as ester groups are present.
　芳香族ビニル系重合体ブロック（Ａ）と脂肪族ビニル系重合体ブロック（Ｂ）とを構成成分とするブロック共重合体のブロック構造は特に限定されないが、芳香族ビニル系重合体ブロック（Ａ）は複数あることが望ましく、少なくとも１つの脂肪族ビニル系重合体ブロック（Ｂ）の両端は、ブロック共重合体の末端でないことが望ましい。例としてＡ－Ｂ－Ａ型トリブロック共重合体、Ａ－Ｂ－Ａ型トリブロック共重合体とＡ－Ｂ型ジブロック共重合体との混合物、Ａ－Ｂ－Ａ－Ｂ型テトラブロック共重合体、Ａ－Ｂ－Ａ－Ｂ－Ａ型ペンタブロック共重合体、Ｂ－Ａ－Ｂ－Ａ－Ｂ型ペンタブロック共重合体、（Ａ－Ｂ）ｎＸ型共重合体（Ｘはカップリング成分を表す）、（Ｂ－Ａ）ｎＸ型共重合体（Ｘはカップリング成分を表す）等が挙げられる。これらのブロック共重合体は、各単独で用いても２種以上組み合わせて用いてもよい。ここでブロック共重合体が芳香族ビニル系重合体ブロック（Ａ）及び／又は脂肪族ビニル系重合体ブロック（Ｂ）を複数有する場合は、これらのブロックは同じであっても異なっていても良い。 Although the block structure of the block copolymer comprising the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) as constituent components is not particularly limited, the aromatic vinyl polymer block (A) It is desirable that there is a plurality, and that both ends of at least one aliphatic vinyl polymer block (B) are not terminals of the block copolymer. Examples include an ABA type triblock copolymer, an ABBA type triblock copolymer and an AB type diblock copolymer, an ABBA type AB block copolymer. Polymer, ABABABA type pentablock copolymer, BABBAB type pentablock copolymer, (AB) nX type copolymer (X is coupling) And (BA) nX-type copolymer (X represents a coupling component). These block copolymers may be used alone or in combination of two or more. When the block copolymer has a plurality of aromatic vinyl polymer blocks (A) and / or aliphatic vinyl polymer blocks (B), these blocks may be the same or different. .
　本発明の高分子電解質を構成するブロック共重合体において、該ブロック共重合体を構成する芳香族ビニル系重合体ブロック（Ａ）と脂肪族ビニル系重合体ブロック（Ｂ）との重量比は得られるブロック共重合体の要求性能によって適宜選択されるが、イオン伝導度の観点からは９５：５～５５：４５であるのが好ましく、耐水性の観点からは４５：５５～５：９５が好ましく、イオン伝導度と耐水性を両立させるためには６０：４０～４０：６０が好ましい。この重量比が９５：５～５：９５である場合には、ミクロ相分離により芳香族ビニル系重合体ブロック（Ａ）の形成するイオンチャンネルがシリンダー状ないし連続相となるのに有利であって、実用上十分なイオン伝導性が発現し、また疎水性である脂肪族ビニル系重合体ブロック（Ｂ）の割合が適切となって優れた耐水性が発現する。なお、ここで上記重量比は、ブロック共重合体の全てのイオン伝導性基を水素に置換した重合体ブロックを想定して算出する。 In the block copolymer constituting the polymer electrolyte of the present invention, the weight ratio of the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) constituting the block copolymer is obtained. Although it is appropriately selected depending on the required performance of the block copolymer to be obtained, it is preferably 95: 5 to 55:45 from the viewpoint of ionic conductivity, and 45:55 to 5:95 is preferable from the viewpoint of water resistance. In order to achieve both ionic conductivity and water resistance, 60:40 to 40:60 is preferable. When this weight ratio is 95: 5 to 5:95, it is advantageous for the ion channel formed by the aromatic vinyl polymer block (A) to be a cylindrical or continuous phase by microphase separation. The practically sufficient ionic conductivity is exhibited, and the hydrophobic vinyl polymer block (B), which is hydrophobic, has an appropriate ratio and exhibits excellent water resistance. Here, the weight ratio is calculated assuming a polymer block in which all ion conductive groups of the block copolymer are replaced with hydrogen.
　本発明で使用するブロック共重合体は、一部にグラフト結合を含むものも包含する。一部にグラフト結合を含むブロック共重合体としては、構成する重合体ブロックの一部がブロック共重合体の主たる構造（例えば主鎖）にグラフト結合したものなどが挙げられる。 The block copolymer used in the present invention includes those partially containing graft bonds. Examples of the block copolymer partially containing a graft bond include those in which a part of the constituting polymer block is grafted to the main structure (for example, main chain) of the block copolymer.
　本発明で用いるブロック共重合体の数平均分子量は特に制限されないが、イオン伝導性基を考慮しない数平均分子量は標準ポリスチレン換算の数平均分子量として、通常、１０，０００～１，０００，０００が好ましく、１５，０００～７００，０００がより好ましく、２０，０００～５００，０００がより一層好ましい。 The number average molecular weight of the block copolymer used in the present invention is not particularly limited, but the number average molecular weight not considering the ion conductive group is usually 10,000 to 1,000,000 as the number average molecular weight in terms of standard polystyrene. Preferably, 15,000 to 700,000 is more preferable, and 20,000 to 500,000 is even more preferable.
　本発明の高分子電解質を構成するブロック共重合体は芳香族ビニル系重合体ブロック（Ａ）にイオン伝導性基を有することが必要である。本発明でイオン伝導性に言及する場合のイオンとしてはプロトンなどが挙げられる。イオン伝導性基としては、該高分子電解質を用いて作製される膜－電極接合体が十分なイオン伝導度を発現できるような基であれば特に限定されないが、中でも－ＳＯ3Ｍ又は－ＰＯ3ＨＭ（式中、Ｍは水素原子、アンモニウムイオン又はアルカリ金属イオンを表す）で表されるスルホン酸基、ホスホン酸基又はそれらの塩が好適に用いられる。イオン伝導性基としては、また、カルボキシル基又はその塩も用いることができる。芳香族ビニル系重合体ブロック（Ａ）がイオン伝導性基を有することで、高分子電解質の耐ラジカル性を向上させるのに特に有効である。 The block copolymer constituting the polymer electrolyte of the present invention needs to have an ion conductive group in the aromatic vinyl polymer block (A). Examples of ions in the present invention when referring to ionic conductivity include protons. The ion conductive group is not particularly limited as long as the membrane-electrode assembly produced using the polymer electrolyte can exhibit sufficient ionic conductivity, and in particular, —SO 3 M or —PO A sulfonic acid group, a phosphonic acid group or a salt thereof represented by 3 HM (wherein M represents a hydrogen atom, an ammonium ion or an alkali metal ion) is preferably used. As the ion conductive group, a carboxyl group or a salt thereof can also be used. The aromatic vinyl polymer block (A) having an ion conductive group is particularly effective for improving the radical resistance of the polymer electrolyte.
　イオン伝導性基の導入量は、得られるブロック共重合体の要求性能等によって適宜選択されるが、固体高分子型燃料電池用の高分子電解質膜として使用するのに十分なイオン伝導性を発現するためには、通常、ブロック共重合体のイオン交換容量（全体ＩＥＣ）が０．４０ｍｅｑ／ｇ以上となるような量であることが好ましく、０．５０ｍｅｑ／ｇ以上となるような量であることがより好ましく、０．６０ｍｅｑ／ｇ以上となるような量であることが更に好ましい。ブロック共重合体のイオン交換容量の上限については、イオン交換容量が大きくなりすぎると親水性が高まり耐水性が不十分になる傾向となるので、４．５ｍｅｑ／ｇ以下であるのが好ましく、４．０ｍｅｑ／ｇ以下であるのがより好ましく、３．５ｍｅｑ／ｇ以下であるのが更に好ましい。 The amount of ion-conducting group introduced is appropriately selected depending on the required performance of the resulting block copolymer, etc., but exhibits sufficient ion conductivity for use as a polymer electrolyte membrane for a polymer electrolyte fuel cell. In order to achieve this, it is usually preferable that the block copolymer has an ion exchange capacity (overall IEC) of 0.40 meq / g or more, and preferably 0.50 meq / g or more. It is more preferable that the amount is 0.60 meq / g or more. The upper limit of the ion exchange capacity of the block copolymer is preferably 4.5 meq / g or less, because if the ion exchange capacity becomes too large, the hydrophilicity tends to increase and the water resistance tends to be insufficient. It is more preferably 0.0 meq / g or less, and further preferably 3.5 meq / g or less.
　本発明で用いるブロック共重合体は主としてイオン伝導性基を有しない芳香族ビニル系化合物単位を繰り返し単位とする芳香族ビニル系重合体ブロック（Ｃ）を含んでいても良い。 The block copolymer used in the present invention may contain an aromatic vinyl polymer block (C) mainly comprising an aromatic vinyl compound unit having no ion conductive group as a repeating unit.
　芳香族ビニル系重合体ブロック（Ｃ）が前記高分子電解質の２０～６０重量％を占めることによって、膜として使用する時の機械的強度に優れ、好ましい。より好ましくは２３～５０重量％を占めることであり、更に好ましくは２５～４０重量％を占めることである。 Since the aromatic vinyl polymer block (C) accounts for 20 to 60% by weight of the polymer electrolyte, it is excellent in mechanical strength when used as a membrane, which is preferable. More preferably, it occupies 23 to 50% by weight, and further preferably occupies 25 to 40% by weight.
　主としてイオン伝導性基を有しない芳香族ビニル系化合物単位を繰り返し単位とする芳香族ビニル系重合体ブロック（Ｃ）とは、芳香族ビニル系化合物単位を主たる繰り返し単位とする重合体ブロックである。該重合体ブロックは高分子電解質の成形体（例えば高分子電解質膜）の形状安定性を優れたものとする。したがって脂肪族ビニル系重合体ブロック（Ｂ）がゴム状重合体ブロックである場合は特に有用である。芳香族ビニル系重合体ブロック（Ｃ）は、芳香族ビニル系重合体ブロック（Ａ）、脂肪族ビニル系重合体ブロック（Ｂ）のいずれとも相分離して拘束相を形成することが好ましい。すなわちイオン伝導性を有しない芳香族ビニル系重合体ブロック（Ｃ）が独立した相を形成するのでより形状安定性が優れたものとなる。 The aromatic vinyl polymer block (C) having an aromatic vinyl compound unit mainly having no ion conductive group as a repeating unit is a polymer block having an aromatic vinyl compound unit as a main repeating unit. The polymer block is excellent in shape stability of a polymer electrolyte molded body (for example, a polymer electrolyte membrane). Therefore, it is particularly useful when the aliphatic vinyl polymer block (B) is a rubbery polymer block. The aromatic vinyl polymer block (C) is preferably phase-separated from both the aromatic vinyl polymer block (A) and the aliphatic vinyl polymer block (B) to form a constrained phase. That is, since the aromatic vinyl polymer block (C) having no ionic conductivity forms an independent phase, the shape stability is further improved.
　芳香族ビニル系重合体ブロック（Ｃ）は主としてイオン伝導性基を有しない芳香族ビニル系化合物単位を繰り返し単位とする。ここで主としてイオン伝導性基を有さない芳香族ビニル系化合物単位を繰り返し単位とするとは芳香族ビニル系重合体ブロック（Ｃ）が実質的にイオン伝導性を有さない程度であることを意味しており、例えば芳香族ビニル系重合体ブロック（Ｃ）の繰り返し単位あたりのイオン伝導性基含有量が０．１以下、より好ましくは０．０１以下であり、最も好ましくは全く有さないことである。または芳香族ビニル系重合体ブロック（Ａ）の有するイオン伝導性基に対して１／１０以下であることが好ましく、１／２０であることがより好ましく、１／１００以下であることが更に好ましい。この結果、芳香族ビニル系重合体ブロック（Ｃ）は実質的にイオン伝導性を有しなくなり、イオンチャンネルを形成する芳香族ビニル系重合体ブロック（Ａ）との相分離が良好に発現するので、効率よいイオン伝導を行うことができる。 The aromatic vinyl polymer block (C) is mainly composed of an aromatic vinyl compound unit having no ion conductive group as a repeating unit. Here, the aromatic vinyl-based compound unit having mainly no ion-conducting group as a repeating unit means that the aromatic vinyl-based polymer block (C) has substantially no ion conductivity. For example, the ion conductive group content per repeating unit of the aromatic vinyl polymer block (C) is 0.1 or less, more preferably 0.01 or less, and most preferably not at all. It is. Alternatively, it is preferably 1/10 or less, more preferably 1/20, and even more preferably 1/100 or less with respect to the ion conductive group of the aromatic vinyl polymer block (A). . As a result, the aromatic vinyl polymer block (C) does not substantially have ionic conductivity, and phase separation with the aromatic vinyl polymer block (A) forming the ion channel is favorably expressed. Efficient ion conduction can be performed.
　芳香族ビニル系重合体ブロック（Ｃ）は疎水性であることで芳香族ビニル系重合体ブロック（Ａ）との相分離が良好に起こるので好ましい。例えば水酸基、アミノ基などの親水性基を実質的に有さないことが好ましく、エステル基などの極性基を実質的に有さないことも好ましい。 Since the aromatic vinyl polymer block (C) is hydrophobic, phase separation with the aromatic vinyl polymer block (A) occurs favorably. For example, it is preferably substantially free of hydrophilic groups such as hydroxyl groups and amino groups, and it is also preferred that substantially no polar groups such as ester groups are present.
　ここで、芳香族ビニル系重合体ブロック（Ｃ）の主たる繰り返し単位である芳香族ビニル系化合物単位とは、芳香族ビニル系化合物の重合によって形成できる構造である。該芳香族ビニル系化合物とは、少なくとも１つの芳香環と、少なくとも一つの芳香環上の炭素原子に直結する付加重合性炭素二重結合を含む官能基を少なくとも１つ有する化合物を指す。 Here, the aromatic vinyl compound unit which is the main repeating unit of the aromatic vinyl polymer block (C) is a structure which can be formed by polymerization of an aromatic vinyl compound. The aromatic vinyl compound refers to a compound having at least one functional group containing at least one aromatic ring and an addition polymerizable carbon double bond directly bonded to a carbon atom on at least one aromatic ring.
　上記の芳香族ビニル系化合物が有する芳香環は炭素環式芳香環であるのが好ましく、ベンゼン環、ナフタレン環、アントラセン環、ピレン環等が挙げられる。これら芳香族ビニル系化合物としては、芳香族ビニル系化合物単位は１～３個の炭素数１～８の炭化水素基を芳香環上に有する置換芳香族ビニル系化合物単位であることが望ましい。例えば、芳香環上の水素をビニル基、１－アルキルエテニル基（例えばイソプロペニル基）、１－アリールエテニル基などの置換基で置換した化合物が挙げられる。例えば、スチレン、２－メチルスチレン、３－メチルスチレン、４－メチルスチレン、４－エチルスチレン、４－ｎ－プロピルスチレン、４－イソプロピルスチレン、４－ｎ－ブチルスチレン、４－イソブチルスチレン、４－ｔ－ブチルスチレン、４－ｎ－オクチルスチレン、２，４－ジメチルスチレン、２，５－ジメチルスチレン、３，５－ジメチルスチレン、２，４，６－トリメチルスチレン、２－メトキシスチレン、３－メトキシスチレン、４－メトキシスチレン、ビニルナフタレン、ビニルアントラセン、α－炭素原子に結合した水素原子が炭素数１～４のアルキル基（メチル基、エチル基、ｎ－プロピル基、イソプロピル基、ｎ－ブチル基、イソブチル基、ｓｅｃ－ブチル基、もしくはｔｅｒｔ－ブチル基）、炭素数１～４のハロゲン化アルキル基（クロロメチル基、２－クロロエチル基、３－クロロエチル基等）又はフェニル基で置換された芳香族ビニル系化合物（具体的には、α－メチルスチレン、α，４－ジメチルスチレン、α－メチル－４－エチルスチレン、α－メチル－４－ｔ－ブチルスチレン、α－メチル－４－イソプロピルスチレン、１，１－ジフェニルエチレン等）が挙げられる。 The aromatic ring of the aromatic vinyl compound is preferably a carbocyclic aromatic ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, and a pyrene ring. As these aromatic vinyl compounds, the aromatic vinyl compound unit is preferably a substituted aromatic vinyl compound unit having 1 to 3 hydrocarbon groups having 1 to 8 carbon atoms on the aromatic ring. Examples thereof include compounds in which hydrogen on the aromatic ring is substituted with a substituent such as a vinyl group, 1-alkylethenyl group (eg, isopropenyl group), 1-arylethenyl group. For example, styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, 4-n-propylstyrene, 4-isopropylstyrene, 4-n-butylstyrene, 4-isobutylstyrene, 4- t-butylstyrene, 4-n-octylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,5-dimethylstyrene, 2,4,6-trimethylstyrene, 2-methoxystyrene, 3-methoxy Styrene, 4-methoxystyrene, vinylnaphthalene, vinylanthracene, alkyl groups having 1 to 4 hydrogen atoms bonded to α-carbon atoms (methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group) , Isobutyl group, sec-butyl group, or tert-butyl group), halo having 1 to 4 carbon atoms Aromatic vinyl compounds substituted with alkyl group (chloromethyl group, 2-chloroethyl group, 3-chloroethyl group, etc.) or phenyl group (specifically, α-methylstyrene, α, 4-dimethylstyrene, α-methyl-4-ethylstyrene, α-methyl-4-t-butylstyrene, α-methyl-4-isopropylstyrene, 1,1-diphenylethylene, etc.).
　これらは１種又は２種以上組み合わせて使用できるが、中でも４－ｔ－ブチルスチレン、４－イソプロピルスチレン、α－メチル－４－ｔ－ブチルスチレン、α－メチル－４－イソプロピルスチレンが好ましい。これらの２種以上を共重合させる場合の形態はランダム共重合でもブロック共重合でもグラフト共重合でもテーパード共重合でもよい。 These can be used alone or in combination of two or more, among which 4-t-butylstyrene, 4-isopropylstyrene, α-methyl-4-t-butylstyrene, and α-methyl-4-isopropylstyrene are preferable. The form in the case of copolymerizing two or more of these may be random copolymerization, block copolymerization, graft copolymerization or tapered copolymerization.
　芳香族ビニル系重合体ブロック（Ｃ）は、本発明の効果を損なわない範囲内で１種もしくは複数の他の単量体単位を含んでいてもよい。かかる他の単量体としては、例えば、炭素数４～８の共役ジエン（１，３－ブタジエン、１，３－ペンタジエン、イソプレン、１，３－ヘキサジエン、２，４－ヘキサジエン、２，３－ジメチル－１，３－ブタジエン、２－エチル－１，３－ブタジエン、１，３－ヘプタジエン、１，４－ヘプタジエン、３，５－ヘプタジエン等）、炭素数２～８のアルケン（エチレン、プロピレン、１－ブテン、２－ブテン、イソブテン、１－ペンテン、２－ペンテン、１－ヘキセン、２－ヘキセン、１－ヘプテン、２－ヘプテン、１－オクテン、２－オクテン等）、（メタ）アクリル酸エステル（（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ブチル等）、ビニルエステル（酢酸ビニル、プロピオン酸ビニル、酪酸ビニル、ピバリン酸ビニル等）、ビニルエーテル（メチルビニルエーテル、イソブチルビニルエーテル等）等が挙げられる。上記他の単量体との共重合形態はランダム共重合であることが望ましい。 The aromatic vinyl polymer block (C) may contain one or more other monomer units within a range not impairing the effects of the present invention. Examples of such other monomers include conjugated dienes having 4 to 8 carbon atoms (1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 2,4-hexadiene, 2,3- Dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-heptadiene, 1,4-heptadiene, 3,5-heptadiene, etc.), alkenes having 2 to 8 carbon atoms (ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-heptene, 2-heptene, 1-octene, 2-octene, etc.), (meth) acrylic acid ester (Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl butyrate, Vinyl valine acid, etc.), vinyl ethers (methyl vinyl ether, isobutyl vinyl ether, etc.), and the like. The copolymerization form with the other monomer is desirably random copolymerization.
　芳香族ビニル系重合体ブロック（Ｃ）はブロック共重合体の６０重量％以下の範囲で用いることが好ましく、５０重量％以下の範囲で用いることがより好ましく、４０重量％以下の範囲で用いることがより好ましい。 The aromatic vinyl polymer block (C) is preferably used in the range of 60% by weight or less of the block copolymer, more preferably in the range of 50% by weight or less, and in the range of 40% by weight or less. Is more preferable.
　芳香族ビニル系重合体ブロック（Ｃ）と芳香族ビニル系重合体ブロック（Ａ）との比率に特に限定はないが、イオン伝導性基を導入する前の単量体単位の比率として、８５：１５～０：１００の範囲であることが好ましく、芳香族ビニル系重合体ブロック（Ｃ）による機械的強度と、高いイオン伝導性を両立する上では、６５：３５～２０：８０の範囲であることが好ましく、５５：４５～３５：６５の範囲であることがより好ましく、４５：５５～３５：６５の範囲であることがさらに好ましい。 The ratio of the aromatic vinyl polymer block (C) to the aromatic vinyl polymer block (A) is not particularly limited, but the ratio of the monomer units before introducing the ion conductive group is 85: It is preferably in the range of 15 to 0: 100, and in the range of 65:35 to 20:80 in order to achieve both the mechanical strength of the aromatic vinyl polymer block (C) and high ionic conductivity. Preferably, it is in the range of 55:45 to 35:65, more preferably in the range of 45:55 to 35:65.
　芳香族ビニル系重合体ブロック（Ｃ）は、下記の一般式（ａ）で表される芳香族ビニル系化合物単位を主たる繰り返し単位として有する重合体ブロックから構成されていてもよい。一般式（ａ）のＲ1で表される炭素数１～４のアルキル基は、直鎖状でも分岐状でもよく、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｓｅｃ－ブチル基、イソブチル基、ｔｅｒｔ－ブチル基などが挙げられる。一般式（ａ）のＲ2～Ｒ4で表される炭素数１～８のアルキル基は、直鎖状でも分岐状でもよく、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｓｅｃ－ブチル基、イソブチル基、ｔｅｒｔ－ブチル基、ペンチル基、イソペンチル基、ネオペンチル基、ｔｅｒｔ－ペンチル基、ヘキシル基、１－メチルペンチル基、ヘプチル基、オクチル基などが挙げられる。一般式（ａ）で表される芳香族ビニル系化合物単位の好適な具体例としては、４－メチルスチレン単位、４－ｔｅｒｔ－ブチルスチレン単位、α，４－ジメチルスチレン単位、α－メチル－４－ｔｅｒｔ－ブチルスチレン単位等が挙げられ、これらは１種または２種以上組み合わせて用いてもよい。これら２種以上を重合（共重合）させる場合の形態はランダム共重合でもブロック共重合でもグラフト共重合でもテーパード共重合でもよい。 The aromatic vinyl polymer block (C) may be composed of a polymer block having an aromatic vinyl compound unit represented by the following general formula (a) as a main repeating unit. The alkyl group having 1 to 4 carbon atoms represented by R 1 in the general formula (a) may be linear or branched, and is a methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group. , Isobutyl group, tert-butyl group and the like. The alkyl group having 1 to 8 carbon atoms represented by R 2 to R 4 in the general formula (a) may be linear or branched, and is methyl, ethyl, propyl, isopropyl, butyl, sec -Butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, 1-methylpentyl group, heptyl group, octyl group and the like. Preferable specific examples of the aromatic vinyl compound unit represented by the general formula (a) include 4-methylstyrene unit, 4-tert-butylstyrene unit, α, 4-dimethylstyrene unit, α-methyl-4. -Tert-butylstyrene units and the like may be mentioned, and these may be used alone or in combination of two or more. The form in the case of polymerizing (copolymerizing) two or more of these may be random copolymerization, block copolymerization, graft copolymerization, or tapered copolymerization.
Figure JPOXMLDOC01-appb-C000001
 （式中、Ｒ1は水素原子又は炭素数１～４のアルキル基であり、Ｒ2～Ｒ4はそれぞれ独立に水素原子又は炭素数１～８のアルキル基を表すが、少なくとも１つは炭素数１～８のアルキル基を表す）
Figure JPOXMLDOC01-appb-C000001
 Wherein R 1 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R 2 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, but at least one of them is carbon Represents an alkyl group of 1 to 8)
　本発明の高分子電解質の製造方法の一つとして、イオン伝導性基を有しないブロック共重合体を製造後、イオン伝導性基を導入する方法が挙げられる。例えばイオン伝導性基としてスルホン酸基を導入する場合、ポリスチレンのスルホン化反応は芳香環のパラ位に優先的に起こるので、芳香族ビニル系重合体ブロックの主たる繰り返し単位が上記４－メチルスチレン単位、４－ｔｅｒｔ－ブチルスチレン単位、α，４－ジメチルスチレン単位、α－メチル－４－ｔｅｒｔ－ブチルスチレン単位等、４位（パラ位）が置換されたスチレン構造である場合、対応する芳香族ビニル系重合体ブロックへのスルホン化反応は起こりにくくなる（スルホン化の反応速度が低下、または完全に反応が進行しない）。このため芳香族ビニル系重合体ブロックにスルホン酸基が導入されにくくなり、該芳香族ビニル系重合体ブロックをイオン伝導性基を有しない芳香族ビニル化合物単位とする上で有利である。特に４位が嵩高い置換基で置換された構造である場合一層有利であり、該置換基としてはイソプロピル基、ｓｅｃ－ブチル基、ｔｅｒｔ－ブチル基が挙げられ、４－ｔｅｒｔ－ブチルスチレン単位がより有利である。このように、芳香族ビニル系重合体ブロック（Ｃ）をイオン伝導性基の導入が起こりにくい芳香族ビニル系化合物（例えば置換芳香族ビニル系化合物）の重合によって得ること、少なくとも芳香族ビニル系重合体ブロック（Ａ）を構成するための芳香族ビニル系化合物（例えば無置換芳香族ビニル系化合物）よりも十分イオン伝導性基導入反応の反応性が低いモノマーを用いることが、イオン伝導性基を有しないブロック共重合体を製造後、イオン伝導性基を導入する方法によって本発明の高分子電解質を製造する上で有利である。 As one method for producing the polymer electrolyte of the present invention, there is a method of introducing an ion conductive group after producing a block copolymer having no ion conductive group. For example, when a sulfonic acid group is introduced as an ion conductive group, the sulfonation reaction of polystyrene takes place preferentially at the para position of the aromatic ring, so that the main repeating unit of the aromatic vinyl polymer block is the 4-methylstyrene unit. 4-tert-butylstyrene unit, α, 4-dimethylstyrene unit, α-methyl-4-tert-butylstyrene unit, etc., when the styrene structure is substituted at the 4-position (para-position), the corresponding aromatic The sulfonation reaction to the vinyl polymer block is less likely to occur (the sulfonation reaction rate is reduced or the reaction does not proceed completely). For this reason, it becomes difficult to introduce a sulfonic acid group into the aromatic vinyl polymer block, which is advantageous in making the aromatic vinyl polymer block an aromatic vinyl compound unit having no ion conductive group. In particular, it is more advantageous when the structure is substituted at the 4-position with a bulky substituent. Examples of the substituent include an isopropyl group, a sec-butyl group, and a tert-butyl group, and a 4-tert-butylstyrene unit includes More advantageous. As described above, the aromatic vinyl polymer block (C) is obtained by polymerization of an aromatic vinyl compound (for example, a substituted aromatic vinyl compound) in which introduction of an ion conductive group is unlikely to occur. It is possible to use a monomer that is sufficiently less reactive in introducing an ion conductive group than an aromatic vinyl compound (for example, an unsubstituted aromatic vinyl compound) for constituting the combined block (A). It is advantageous in producing the polymer electrolyte of the present invention by a method of introducing an ion conductive group after producing a block copolymer not having it.
　ブロック共重合体にイオン伝導性基を導入する方法で本発明の高分子電解質を製造する場合、イオン伝導性基導入前のブロック共重合体において、芳香族ビニル系重合体ブロック（Ｃ）に相当する芳香族ビニル系重合体ブロックは、芳香族ビニル系重合体ブロック（Ａ）に相当する芳香族ビニル系重合体ブロックに比べて非常にイオン伝導性基が導入されにくく、このため、芳香族ビニル系重合体ブロック（Ａ）のイオン伝導性基導入率が、あらゆる場合において芳香族ビニル系重合体ブロック（Ｃ）よりも有意に高い。芳香族ビニル系重合体ブロック（Ａ）のイオン伝導性基は、ブロック共重合体の全イオン伝導性基の少なくとも８５％以上を占めることが好ましく、９０％以上を占めることがより好ましく、９５％以上を占めることが更に好ましい。 When the polymer electrolyte of the present invention is produced by a method of introducing an ion conductive group into the block copolymer, it corresponds to the aromatic vinyl polymer block (C) in the block copolymer before the introduction of the ion conductive group. As compared with the aromatic vinyl polymer block corresponding to the aromatic vinyl polymer block (A), the aromatic vinyl polymer block is very difficult to introduce an ion conductive group. The ion conductive group introduction rate of the polymer block (A) is significantly higher than that of the aromatic vinyl polymer block (C) in all cases. The ion conductive group of the aromatic vinyl polymer block (A) preferably occupies at least 85%, more preferably 90% or more of the total ion conductive group of the block copolymer, 95% It is more preferable to occupy the above.
　拘束相としての機能を果たす観点から、上記した芳香族ビニル系化合物単位は、芳香族ビニル系重合体ブロック（Ｃ）の主たる繰り返し単位であり、５０重量％を超えている。また７０重量％以上を占めることがより好ましく、９０重量％以上を占めることがより一層好ましい。 From the viewpoint of fulfilling the function as a constrained phase, the above-described aromatic vinyl compound unit is the main repeating unit of the aromatic vinyl polymer block (C) and exceeds 50% by weight. Further, it is more preferably 70% by weight or more, and still more preferably 90% by weight or more.
　芳香族ビニル系重合体ブロック（Ｃ）の分子量は、高分子電解質の性状、要求性能、他の重合体成分等によって適宜選択される。分子量が大きい場合、高分子電解質の力学特性が高くなる傾向にあるが、大きすぎるとブロック共重合体の成形、製膜が困難になり、分子量が小さい場合、力学特性が低くなる傾向にあり、必要性能に応じて分子量を適宜選択することが重要である。標準ポリスチレン換算の数平均分子量として、通常、８００～５００，０００の間から選択されるのが好ましく、２，０００～１５０，０００の間から選択されるのがより好ましく、３，０００～５０，０００の間から選択されるのがさらに好ましい。 The molecular weight of the aromatic vinyl polymer block (C) is appropriately selected depending on the properties of the polymer electrolyte, required performance, other polymer components, and the like. When the molecular weight is large, the mechanical properties of the polymer electrolyte tend to be high, but when it is too large, it becomes difficult to mold and form a block copolymer, and when the molecular weight is small, the mechanical properties tend to be low, It is important to select the molecular weight appropriately according to the required performance. The number average molecular weight in terms of standard polystyrene is usually preferably selected from 800 to 500,000, more preferably from 2,000 to 150,000, more preferably from 3,000 to 50,000. More preferably, it is selected from among 000.
　本発明で用いるブロック共重合体が芳香族ビニル系重合体ブロック（Ｃ）、芳香族ビニル系重合体ブロック（Ａ）及び脂肪族ビニル系重合体ブロック（Ｂ）から構成される場合、該ブロック共重合体の構造は、特に限定されないが、例としてＡ－Ｂ－Ｃ－Ａテトラブロック共重合体、Ｂ－Ａ－Ｂ－Ｃテトラブロック共重合体、Ａ－Ｂ－Ｃ－Ｂテトラブロック共重合体、Ｃ－Ｂ－Ｃ－Ａテトラブロック共重合体、Ａ－Ｂ－Ａ－Ｃテトラブロック共重合体、Ａ－Ｃ－Ｂ－Ｃ－Ａペンタブロック共重合体、Ｃ－Ａ－Ｂ－Ａ－Ｃペンタブロック共重合体、Ａ－Ｃ－Ｂ－Ｃ－Ａペンタブロック共重合体、Ｃ－Ｂ－Ａ－Ｂ－Ｃペンタブロック共重合体、Ａ－Ｂ－Ｃ－Ａ－Ｂペンタブロック共重合体、Ａ－Ｂ－Ｃ－Ａ－Ｃペンタブロック共重合体、Ａ－Ｂ－Ｃ－Ｂ－Ｃペンタブロック共重合体、Ａ－Ｂ－Ａ－Ｂ－Ｃペンタブロック共重合体、Ａ－Ｂ－Ａ－Ｃ－Ｂペンタブロック共重合体、Ｂ－Ａ－Ｂ－Ａ－Ｃペンタブロック共重合体、Ｂ－Ａ－Ｂ－Ｃ－Ａペンタブロック共重合体、Ｂ－Ａ－Ｂ－Ｃ－Ｂペンタブロック共重合体、Ｃ－Ａ－Ｃ－Ｂ－Ｃペンタブロック共重合体等が挙げられる。拘束性の観点から、Ｃブロックを複数有することが好ましく、特に両端にＣブロックを有することが好ましい。また、本発明の高分子電解質を乳化させて用いる場合は、乳化液の調製し易さの観点から、Ａブロックを両端に有することが好ましい。また有機溶媒への溶解性、分散性の観点からＣ－Ａ－Ｃ－Ｂ－Ｃペンタブロック共重合体が望ましい。 When the block copolymer used in the present invention comprises an aromatic vinyl polymer block (C), an aromatic vinyl polymer block (A) and an aliphatic vinyl polymer block (B), the block copolymer The structure of the polymer is not particularly limited, but examples include an ABCA tetrablock copolymer, an ABBC tetrablock copolymer, and an ABCB tetrablock copolymer. Copolymer, C—B—C—A tetrablock copolymer, A—B—A—C tetra block copolymer, A—C—B—C—A penta block copolymer, C—A—B—A -C pentablock copolymer, ABCCBCA pentablock copolymer, CBABBC pentablock copolymer, ABCBAB block Polymer, ABCA-A-C pentablock copolymer, AB C—B—C—Pentablock copolymer, A—A—A—B—C—Penta block copolymer, A—A—A—C—B—Penta block copolymer, B—A—B—A—C Pentablock copolymer, BACBCA pentablock copolymer, BABBCB pentablock copolymer, CACBBC pentablock copolymer Etc. From the viewpoint of restraint, it is preferable to have a plurality of C blocks, and it is particularly preferable to have C blocks at both ends. Moreover, when emulsifying and using the polymer electrolyte of this invention, it is preferable to have A block at both ends from a viewpoint of the ease of preparation of an emulsion. Further, from the viewpoint of solubility and dispersibility in an organic solvent, a C—A—C—B—C pentablock copolymer is desirable.
　本発明で使用するブロック共重合体は、一部にグラフト結合を含むものも包含する。一部にグラフト結合を含むブロック共重合体としては、構成する重合体ブロックの一部がブロック共重合体の主たる部分（例えば主鎖）にグラフト結合したものなどが挙げられる。 The block copolymer used in the present invention includes those partially containing graft bonds. Examples of the block copolymer partially containing a graft bond include those in which a part of the constituting polymer block is graft-bonded to a main part (for example, main chain) of the block copolymer.
　本発明で用いられる高分子電解質におけるブロック共重合体の製造方法に関しては、特に限定されず、公知の方法を用いることができるが、イオン伝導性基を有さないブロック共重合体を製造した後、イオン伝導性基を結合させる方法が好ましい。以下、該イオン伝導性基を有さないブロック共重合体における芳香族ビニル系重合体ブロック（Ａ）に相当するイオン伝導性基を有さない重合体ブロックを芳香族ビニル系重合体ブロック（Ａ）’として、説明する。 The production method of the block copolymer in the polymer electrolyte used in the present invention is not particularly limited, and a known method can be used, but after producing the block copolymer having no ion conductive group. A method of bonding an ion conductive group is preferable. Hereinafter, a polymer block having no ion conductive group corresponding to the aromatic vinyl polymer block (A) in the block copolymer having no ion conductive group is referred to as an aromatic vinyl polymer block (A ) '.
　芳香族ビニル系重合体ブロック（Ａ）’又は脂肪族ビニル系重合体ブロック（Ｂ）を構成する単量体の種類、分子量等によって、芳香族ビニル系重合体ブロック（Ａ）’又は脂肪族ビニル系重合体ブロック（Ｂ）の製造方法は、ラジカル重合法、アニオン重合法、カチオン重合法、配位重合法等から適宜選択されるが、工業的な容易さから、ラジカル重合法、アニオン重合法、カチオン重合法が好ましく選択される。特に、分子量制御、分子量分布制御、重合体構造制御、芳香族ビニル系重合体ブロック（Ａ）’と脂肪族ビニル系重合体ブロック（Ｂ）との結合の容易さ等からいわゆるリビング重合法が好ましく、具体的にはリビングラジカル重合法、リビングアニオン重合法、リビングカチオン重合法が好ましい。 Aromatic vinyl polymer block (A) 'or aliphatic vinyl polymer block (A)' or aliphatic vinyl polymer block (B), depending on the type, molecular weight, etc. of the monomers constituting the aromatic vinyl polymer block (A) 'or aliphatic vinyl polymer block (B) The production method of the polymer block (B) is appropriately selected from a radical polymerization method, an anionic polymerization method, a cationic polymerization method, a coordination polymerization method, and the like. From the industrial easiness, a radical polymerization method and an anionic polymerization method are used. The cationic polymerization method is preferably selected. In particular, the so-called living polymerization method is preferable from the viewpoints of molecular weight control, molecular weight distribution control, polymer structure control, ease of bonding between the aromatic vinyl polymer block (A) ′ and the aliphatic vinyl polymer block (B), and the like. Specifically, a living radical polymerization method, a living anion polymerization method, and a living cation polymerization method are preferable.
　製造方法の具体例として、４－ビニルビフェニル等の芳香族ビニル系化合物を主たる繰り返し単位とする芳香族ビニル系重合体ブロック（Ａ）’及び共役ジエンからなる脂肪族ビニル系重合体ブロック（Ｂ）を成分とするブロック共重合体の製造方法について述べる。
　この場合、工業的容易さ、分子量、分子量分布、芳香族ビニル系重合体ブロック（Ａ）’と脂肪族ビニル系重合体ブロック（Ｂ）との結合の容易さ等からリビングアニオン重合法で製造するのが好ましく、次のような具体的な合成例が示される。 Specific examples of the production method include an aromatic vinyl polymer block (A) ′ having an aromatic vinyl compound such as 4-vinylbiphenyl as a main repeating unit and an aliphatic vinyl polymer block (B) comprising a conjugated diene. A method for producing a block copolymer containing as a component will be described.
In this case, it is produced by a living anionic polymerization method from the viewpoint of industrial ease, molecular weight, molecular weight distribution, ease of bonding between the aromatic vinyl polymer block (A) ′ and the aliphatic vinyl polymer block (B), and the like. And the following specific synthesis examples are shown.
（１）トルエン溶媒中でアニオン重合開始剤を用いて、１０～４０℃の温度条件下で、４－ビニルビフェニル等の芳香族ビニル系化合物を重合し、その後共役ジエン、４－ビニルビフェニル等の芳香族ビニル系化合物を逐次重合させ、Ａ’－Ｂ－Ａ’型ブロック共重合体を得る方法。 (1) An aromatic vinyl compound such as 4-vinylbiphenyl is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then conjugated diene, 4-vinylbiphenyl, etc. A method of sequentially polymerizing aromatic vinyl compounds to obtain an A′-BA ′ type block copolymer.
（２）トルエン溶媒中でアニオン重合開始剤を用いて、１０～４０℃の温度条件下で、４－ビニルビフェニル等の芳香族ビニル系化合物を重合し、その後共役ジエンを重合させた後、安息香酸フェニル等のカップリング剤を添加してＡ’－Ｂ－Ａ’型ブロック共重合体を得る方法。 (2) An aromatic vinyl compound such as 4-vinylbiphenyl is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then conjugated diene is polymerized. A method of obtaining an A′-BA ′ type block copolymer by adding a coupling agent such as acid phenyl.
　製造方法の具体例として、４－ｔｅｒｔ－ブチルスチレン等の芳香族ビニル系化合物を主たる繰り返し単位とする芳香族ビニル系重合体ブロック（Ｃ）、４－ビニルビフェニル等の芳香族ビニル系化合物を主たる繰り返し単位とする芳香族ビニル系重合体ブロック（Ａ）’及び共役ジエンからなる重合体ブロック（Ｂ）を構成成分とするブロック共重合体の製造方法について述べる。この場合、工業的容易さ、分子量、分子量分布、重合体ブロック（Ｃ）、（Ｂ）及び（Ａ）’の結合の容易さ等からリビングアニオン重合法が好ましく、次のような具体的な合成例が挙げられ、採用／応用することができる。 Specific examples of the production method include aromatic vinyl polymer block (C) having an aromatic vinyl compound such as 4-tert-butylstyrene as the main repeating unit, and aromatic vinyl compounds such as 4-vinylbiphenyl. A method for producing a block copolymer comprising as constituent components an aromatic vinyl polymer block (A) ′ as a repeating unit and a polymer block (B) comprising a conjugated diene will be described. In this case, the living anionic polymerization method is preferred from the viewpoint of industrial ease, molecular weight, molecular weight distribution, ease of bonding of polymer blocks (C), (B) and (A) ′, and the following specific synthesis Examples are given and can be adopted / applied.
（３）トルエン溶媒中でアニオン重合開始剤を用いて、１０～４０℃の温度条件下で、４－ｔｅｒｔ－ブチルスチレン等の芳香族ビニル系化合物を重合し、その後共役ジエン、４－ビニルビフェニル等の芳香族ビニル系化合物を逐次重合させＣ－Ｂ－Ａ’型ブロック共重合体を得る方法。 (3) An aromatic vinyl compound such as 4-tert-butylstyrene is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then conjugated diene, 4-vinylbiphenyl A method of obtaining a CBA ′ type block copolymer by sequentially polymerizing aromatic vinyl compounds such as
（４）トルエン溶媒中でアニオン重合開始剤を用いて、１０～４０℃の温度条件下で、４－ｔｅｒｔ－ブチルスチレン等の芳香族ビニル系化合物を重合し、その後４－ビニルビフェニル等の芳香族ビニル系化合物、共役ジエンを逐次重合させた後、安息香酸フェニル等のカップリング剤を添加してＣ－Ａ’－Ｂ－Ａ’－Ｃ型ブロック共重合体を得る方法。 (4) An aromatic vinyl compound such as 4-tert-butylstyrene is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then an aromatic such as 4-vinylbiphenyl is used. A method in which a group vinyl compound and a conjugated diene are sequentially polymerized, and then a coupling agent such as phenyl benzoate is added to obtain a CAA'-BA'-C type block copolymer.
（５）トルエン溶媒中でアニオン重合開始剤を用いて、１０～４０℃の温度条件下で、４－ｔｅｒｔ－ブチルスチレン等の芳香族ビニル系化合物を重合し、その後４－ビニルビフェニル等の芳香族ビニル系化合物、共役ジエン、４－ビニルビフェニル等の芳香族ビニル系化合物、４－ｔｅｒｔ－ブチルスチレン等の芳香族ビニル系化合物を逐次重合させＣ－Ａ’－Ｂ－Ａ’－Ｃ型ブロック共重合体を得る方法。 (5) An aromatic vinyl compound such as 4-tert-butylstyrene is polymerized at a temperature of 10 to 40 ° C. using an anionic polymerization initiator in a toluene solvent, and then an aromatic such as 4-vinylbiphenyl. C—A′-BA—C type block by sequentially polymerizing aromatic vinyl compounds such as aromatic vinyl compounds, conjugated dienes, 4-vinylbiphenyl, and aromatic vinyl compounds such as 4-tert-butylstyrene A method for obtaining a copolymer.
　このようにして製造されたブロック共重合体は、脂肪族ビニル系重合体ブロック（Ｂ）を構成する炭素数４～８の共役ジエン単位の二重結合の水素添加反応に供される。該水素添加反応の方法としては、アニオン重合等で得られたブロック共重合体の溶液を耐圧容器に仕込み、Ｎｉ／Ａｌ系等のＺｉｅｇｌｅｒ系水素添加触媒を用いて、水素雰囲気下において水素添加反応を行う方法を例示できる。 The block copolymer thus produced is subjected to a hydrogenation reaction of double bonds of conjugated diene units having 4 to 8 carbon atoms constituting the aliphatic vinyl polymer block (B). As a method of the hydrogenation reaction, a solution of a block copolymer obtained by anionic polymerization or the like is charged into a pressure vessel, and a hydrogenation reaction is performed in a hydrogen atmosphere using a Ziegler type hydrogenation catalyst such as a Ni / Al type. The method of performing can be illustrated.
　次に、得られたブロック共重合体にイオン伝導性基を結合させる方法について述べる。 Next, a method for bonding an ion conductive group to the obtained block copolymer will be described.
　まず、得られたブロック共重合体にスルホン酸基を導入する方法について述べる。スルホン化は、公知のスルホン化の方法で行える。このような方法としては、ブロック共重合体の有機溶媒溶液や縣濁液を調製し、スルホン化剤を添加し混合する方法やブロック共重合体に直接ガス状のスルホン化剤を添加する方法等が例示される。 First, a method for introducing a sulfonic acid group into the obtained block copolymer will be described. Sulfonation can be performed by a known sulfonation method. As such a method, an organic solvent solution or suspension of a block copolymer is prepared, a sulfonating agent is added and mixed, a method of adding a gaseous sulfonating agent directly to the block copolymer, etc. Is exemplified.
　使用するスルホン化剤としては、硫酸、硫酸と脂肪族酸無水物との混合物系、クロロスルホン酸、クロロスルホン酸と塩化トリメチルシリルとの混合物系、三酸化硫黄、三酸化硫黄とトリエチルホスフェートとの混合物系、さらに２，４，６－トリメチルベンゼンスルホン酸に代表される芳香族有機スルホン酸等が例示される。また、使用する有機溶媒としては、塩化メチレン等のハロゲン化炭化水素類、ヘキサン等の直鎖式脂肪族炭化水素類、シクロヘキサン等の環式脂肪族炭化水素類等が例示でき、必要に応じて複数の組み合わせから、適宜選択して使用してもよい。 Sulfonating agents used include sulfuric acid, a mixture of sulfuric acid and aliphatic acid anhydride, chlorosulfonic acid, a mixture of chlorosulfonic acid and trimethylsilyl chloride, sulfur trioxide, a mixture of sulfur trioxide and triethyl phosphate. Examples thereof include aromatic organic sulfonic acids represented by 2,4,6-trimethylbenzenesulfonic acid. Examples of the organic solvent to be used include halogenated hydrocarbons such as methylene chloride, linear aliphatic hydrocarbons such as hexane, cyclic aliphatic hydrocarbons such as cyclohexane, and the like. You may use it, selecting suitably from several combinations.
　得られたブロック共重合体のスルホン化物を含む反応溶液から、スルホン化物を固形物として取り出す方法としては、水中に反応溶液を注ぎスルホン化物を沈殿させた後に溶媒を常圧留去する方法や、反応溶液中に停止剤の水を徐々に添加し懸濁せしめ、スルホン化物を析出させた後に溶媒を常圧留去する方法などが挙げられるが、スルホン化物が微分散化し、その後の水での洗浄効率が高くなる観点から、反応溶液中に停止剤の水を徐々に添加し、懸濁せしめ、スルホン化物を析出させる方法が好適に用いられる。 As a method for removing the sulfonated product as a solid from the reaction solution containing the sulfonated product of the block copolymer, a method of pouring the reaction solution into water and precipitating the sulfonated product, and then distilling off the solvent at atmospheric pressure, Stopper water is gradually added and suspended in the reaction solution, and the sulfonated product is precipitated, and then the solvent is distilled off at atmospheric pressure. From the viewpoint of increasing the washing efficiency, a method of gradually adding and suspending the stopper water in the reaction solution to precipitate the sulfonated product is suitably used.
　次に、得られたブロック共重合体にホスホン酸基を導入する方法について述べる。ホスホン化は、公知のホスホン化の方法で行える。具体的には、例えば、ブロック共重合体の有機溶媒溶液や懸濁液を調製し、無水塩化アルミニウムの存在下、該共重合体をクロロメチルエーテル等と反応させ、芳香環にハロメチル基を導入後、これに三塩化リンと無水塩化アルミニウムを加えて反応させ、さらに加水分解反応を行ってホスホン酸基を導入する方法などが挙げられる。あるいは、該共重合体に三塩化リンと無水塩化アルミニウムを加えて反応させ、芳香環にホスフィン酸基を導入後、硝酸によりホスフィン酸基を酸化してホスホン酸基とする方法等が例示できる。 Next, a method for introducing a phosphonic acid group into the obtained block copolymer will be described. Phosphonation can be performed by a known phosphonation method. Specifically, for example, an organic solvent solution or suspension of a block copolymer is prepared, and the copolymer is reacted with chloromethyl ether or the like in the presence of anhydrous aluminum chloride to introduce a halomethyl group into the aromatic ring. Thereafter, there may be mentioned a method in which phosphorus trichloride and anhydrous aluminum chloride are added and reacted, followed by a hydrolysis reaction to introduce a phosphonic acid group. Alternatively, a method may be exemplified in which phosphorus trichloride and anhydrous aluminum chloride are added to the copolymer and reacted to introduce a phosphinic acid group into the aromatic ring, and then the phosphinic acid group is oxidized with nitric acid to form a phosphonic acid group.
　スルホン化又はホスホン化の程度としては、すでに述べたごとく、ブロック共重合体のイオン交換容量が好ましくは０．４０ｍｅｑ／ｇ以上、より好ましくは０．５０ｍｅｑ／ｇ以上、さらに好ましくは０．６０ｍｅｑ／ｇ以上であり、一方で、好ましくは４．５ｍｅｑ／ｇ以下、より好ましくは４．０ｍｅｑ／ｇ以下、さらに好ましくは３．５ｍｅｑ／ｇ以下であるようにスルホン化またはホスホン化されることが望ましい。これにより実用的なイオン伝導性能が得られる。スルホン化またはホスホン化されたブロック共重合体のイオン交換容量、もしくはブロック共重合体における芳香族ビニル系化合物中のスルホン化率又はホスホン化率は、酸価滴定法、赤外分光スペクトル測定、核磁気共鳴スペクトル（1Ｈ－ＮＭＲスペクトル）測定等の分析手段を用いて算出することができる。 As the degree of sulfonation or phosphonation, as already described, the ion exchange capacity of the block copolymer is preferably 0.40 meq / g or more, more preferably 0.50 meq / g or more, and further preferably 0.60 meq / g. On the other hand, it is desirable to be sulfonated or phosphonated so that it is preferably 4.5 meq / g or less, more preferably 4.0 meq / g or less, and even more preferably 3.5 meq / g or less. . Thereby, practical ion conduction performance is obtained. The ion exchange capacity of the sulfonated or phosphonated block copolymer, or the sulfonation rate or phosphonation rate in the aromatic vinyl compound in the block copolymer is determined by acid value titration, infrared spectroscopic measurement, nuclear It can be calculated using analytical means such as magnetic resonance spectrum ( 1 H-NMR spectrum) measurement.
　イオン伝導性基は、適当な金属イオン（例えばアルカリ金属イオン）あるいは対イオン（例えばアンモニウムイオン）で中和されている塩の形で導入されていてもよい。例えば、適当な方法でイオン交換することにより、スルホン酸基を塩型にしたブロック共重合体を得ることができる。 The ion conductive group may be introduced in the form of a salt neutralized with a suitable metal ion (for example, alkali metal ion) or counter ion (for example, ammonium ion). For example, a block copolymer having a sulfonic acid group in a salt form can be obtained by ion exchange by an appropriate method.
　本発明の高分子電解質は、本発明の効果を損なわない限り、各種添加剤、例えば、軟化剤、安定剤、光安定剤、帯電防止剤、離型剤、難燃剤、発泡剤、顔料、染料、増白剤等を各単独で又は２種以上組み合わせて含有していても良い。 The polymer electrolyte of the present invention can be added to various additives such as a softening agent, a stabilizer, a light stabilizer, an antistatic agent, a release agent, a flame retardant, a foaming agent, a pigment, and a dye as long as the effects of the present invention are not impaired. Further, each of them may contain a brightener or the like alone or in combination of two or more.
　軟化剤としては、パラフィン系、ナフテン系もしくはアロマ系のプロセスオイル等の石油系軟化剤、パラフィン、植物油系軟化剤、可塑剤等が挙げられる。 Examples of the softener include petroleum softeners such as paraffinic, naphthenic or aromatic process oils, paraffin, vegetable oil softeners, plasticizers, and the like.
　安定剤は、フェノール系安定剤、イオウ系安定剤、リン系安定剤等を包含し、具体例としては、２，６－ジ－ｔ－ブチル－ｐ－クレゾール、ペンタエリスチリル－テトラキス［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、１，３，５－トリメチル－２，４，６－トリス（３，５－ジ－ｔ－ブチル－４－ヒドロキシベンジル）ベンゼン、オクタデシル－３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート、トリエチレングリコール－ビス［３－（３－ｔ－ブチル－５－メチル－４－ヒドロキシフェニル）プロピオネート］、２，４－ビス－（ｎ－オクチルチオ）－６－（４－ヒドロキシ－３，５－ジ－ｔ－ブチルアニリノ）－１，３，５－トリアジン、２，２－チオ－ジエチレンビス[３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート]、Ｎ，Ｎ’－ヘキサメチレンビス（３，５－ジ－ｔ－ブチル－４－ヒドロキシ－ヒドロジナマミド）、３，５－ジ－ｔ－ブチル－４－ヒドロキシ－ベンジルホスホネート－ジエチルエステル、トリス－（３，５－ジ－ｔ－ブチル－４－ヒドロキシベンジル）－イソシアヌレート、３，９－ビス｛２－［３－（３－ｔ－ブチル－４－ヒドロキシ－５－メチルフェニル）プロピオニルオキシ］－１，１－ジメチルエチル｝－２，４，８，１０－テトラオキサスピロ［５．５］ウンデカン等のフェノール系安定剤；ペンタエリスリチルテトラキス（３－ラウリルチオプロピオネート）、ジステアリル３，３’－チオジプロピオネート、ジラウリル３，３’－チオジプロピオネート、ジミリスチル３，３’－チオジプロピオネート等のイオウ系安定剤；トリスノニルフェニルホスファイト、トリス（２，４－ジ－ｔ－ブチルフェニル）ホスファイト、ジアステリルペンタエリスリトールジホスファイト、ビス（２，６－ジ－ｔ－ブチル－４－メチルフェニル）ペンタエリスリトールジホスファイト等のリン系安定剤が挙げられる。 Stabilizers include phenol-based stabilizers, sulfur-based stabilizers, phosphorus-based stabilizers, and the like. Specific examples include 2,6-di-t-butyl-p-cresol, pentaerythryl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) Benzene, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, 2,2-thio-diethylenebi [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrodinamide), 3, 5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 3,9-bis {2- [3 Phenols such as-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane Stabilizer; pentaerythrityl tetrakis (3-lauryl thiopropionate), distearyl 3,3'-thiodipropionate, dilauryl 3,3'-thiodipropiate Sulfur stabilizers such as onate and dimyristyl 3,3′-thiodipropionate; trisnonylphenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, diasterylpentaerythritol diphosphite, bis And phosphorus stabilizers such as (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite.
　本発明の高分子電解質におけるブロック共重合体の含有量は、イオン伝導性の観点から、５０重量％以上であることが好ましく、７０重量％以上であることがより好ましく、９０重量％以上であることがより一層好ましい。 From the viewpoint of ion conductivity, the content of the block copolymer in the polymer electrolyte of the present invention is preferably 50% by weight or more, more preferably 70% by weight or more, and 90% by weight or more. It is even more preferable.
　固体高分子型燃料電池用途などに好適な本発明の高分子電解質膜は、膜抵抗、膜強度、ハンドリング性等の観点から、その膜厚が５～３００μｍ程度であることが好ましく、６～２００μｍ程度であることがより好ましく、７～１００μｍ程度であることがさらに好ましい。膜抵抗を低くしたい場合には７～３０μｍ、膜抵抗を低く保ち膜強度を持たせる場合には、２０～６０μｍ、膜強度を重視する場合には５０～１００μｍが好ましい。 The polymer electrolyte membrane of the present invention suitable for use in a polymer electrolyte fuel cell or the like preferably has a thickness of about 5 to 300 μm, preferably 6 to 200 μm, from the viewpoints of membrane resistance, membrane strength, handling properties, and the like. More preferably, it is about 7 to 100 μm. When it is desired to lower the membrane resistance, 7 to 30 μm is preferable. When the membrane resistance is kept low and the membrane strength is increased, 20 to 60 μm is preferable. When the membrane strength is important, 50 to 100 μm is preferable.
　該高分子電解質膜の調製方法については、かかる調製のための通常の方法であればいずれの方法も採用できるが、例えば、高分子電解質膜を構成するブロック共重合体又は該ブロック共重合体及び上記したような添加剤を適当な溶媒と混合して、５重量％以上の該ブロック共重合体の溶液又は懸濁液又は乳化液を調製した後、離型処理済みのＰＥＴフィルム等に、コーターやアプリケーター等を用いて塗布した後、適切な条件で溶媒を除去することによって、所望の厚みを有する高分子電解質膜を得る溶液塗工方法や、ポリテトラフルオロエチレンシート等に５重量％以下の該ブロック共重合体の溶液又は懸濁液又は乳化液をキャストした後、１～数日かけて溶媒を徐々に除去することによって、所望の厚みを有する高分子電解質膜を得るキャスト法や、熱プレス成形、ロール成形、押し出し成形等の公知の方法を用いて成膜する方法などを用いることができるが、良好な強度と柔軟性を有する高分子電解質膜を調整しやすい観点から、溶液塗工方法が好適に用いられる。 As a method for preparing the polymer electrolyte membrane, any method can be adopted as long as it is a normal method for such preparation. For example, a block copolymer constituting the polymer electrolyte membrane or the block copolymer and After the additive as described above is mixed with a suitable solvent to prepare a solution or suspension or emulsion of 5% by weight or more of the block copolymer, the coated film is applied to a release-treated PET film or the like. Or by applying a solution under an appropriate condition after application using an applicator or the like, a solution coating method for obtaining a polymer electrolyte membrane having a desired thickness, or a polytetrafluoroethylene sheet or the like of 5% by weight or less. After casting the block copolymer solution or suspension or emulsion, the solvent is gradually removed over 1 to several days to obtain a polymer electrolyte membrane having a desired thickness. A method of forming a film using a known method such as a cast method, hot press molding, roll molding, extrusion molding, etc. can be used, but it is easy to adjust a polymer electrolyte membrane having good strength and flexibility. Therefore, the solution coating method is preferably used.
　また、得られた高分子電解質膜層の上に、新たに、同じまたは異なるブロック共重合体溶液を塗布して乾燥することにより積層化させてもよい。また、上記のようにして得られた、同じまたは異なる高分子電解質膜同士を熱ロール成形等で圧着させて積層化させてもよい。 Alternatively, the same or different block copolymer solution may be newly applied on the obtained polymer electrolyte membrane layer and dried to be laminated. Further, the same or different polymer electrolyte membranes obtained as described above may be laminated by being pressure-bonded by hot roll molding or the like.
　高分子電解質膜を均一溶液系で調整する場合に使用する溶媒は、ブロック共重合体の構造を破壊することなく、溶液塗工が可能な程度の粘度の溶液を調製することが可能なものであれば特に制限されない。具体的には、塩化メチレン、クロロベンゼン等のハロゲン化炭化水素類、トルエン、キシレン、ベンゼン等の芳香族炭化水素類、ヘキサン、ヘプタン等の直鎖式脂肪族炭化水素類、シクロヘキサン等の環式脂肪族炭化水素類、テトラヒドロフラン等のエーテル類、メタノール、エタノール、プロパノール、イソプロピルアルコール、ブタノール、イソブチルアルコール等のアルコール類、あるいはこれらの混合溶媒等が例示できる。ブロック共重合体の構成、分子量、イオン交換容量等に応じて、上記に例示した溶媒の中から、１種又は２種以上の組み合わせを適宜選択し使用することができるが、特に良好な強度と柔軟性を有する高分子電解質膜を調整しやすい観点から、トルエンとイソブチルアルコールの混合溶媒、トルエンとイソプロピルアルコールの混合溶媒、シクロヘキサンとイソプロピルアルコールの混合溶媒、シクロヘキサンとイソブチルアルコールの混合溶媒、テトラヒドロフラン、テトラヒドロフランとメタノールの混合溶媒、クロロベンゼンが好ましく、特に、トルエンとイソブチルアルコールの混合溶媒、トルエンとイソプロピルアルコールの混合溶媒、クロロベンゼンが好ましい。 The solvent used when preparing the polymer electrolyte membrane in a uniform solution system is capable of preparing a solution having a viscosity that allows solution coating without destroying the structure of the block copolymer. If there is no particular limitation. Specifically, halogenated hydrocarbons such as methylene chloride and chlorobenzene, aromatic hydrocarbons such as toluene, xylene, and benzene, linear aliphatic hydrocarbons such as hexane and heptane, and cyclic fats such as cyclohexane. Examples include aromatic hydrocarbons, ethers such as tetrahydrofuran, alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol and isobutyl alcohol, or mixed solvents thereof. Depending on the configuration of the block copolymer, molecular weight, ion exchange capacity, etc., one or more combinations can be appropriately selected and used from the solvents exemplified above. From the viewpoint of easy adjustment of a flexible polymer electrolyte membrane, a mixed solvent of toluene and isobutyl alcohol, a mixed solvent of toluene and isopropyl alcohol, a mixed solvent of cyclohexane and isopropyl alcohol, a mixed solvent of cyclohexane and isobutyl alcohol, tetrahydrofuran, tetrahydrofuran A mixed solvent of benzene and methanol, chlorobenzene is preferable, and a mixed solvent of toluene and isobutyl alcohol, a mixed solvent of toluene and isopropyl alcohol, and chlorobenzene are particularly preferable.
　次に、高分子電解質膜を乳化液系で調整する場合について述べる。イオン伝導性基を有する芳香族ビニル系重合体ブロック（Ａ）が親水性、脂肪族ビニル系重合体ブロック（Ｂ）が疎水性であるため保護コロイド形成能があり、界面活性剤を使用することなく乳化液を得ることができる。また、水などの極性溶媒を使用することで、極性の高いイオン伝導性基を外殻に有する粒子を容易に製造することができる。 Next, the case where the polymer electrolyte membrane is adjusted with the emulsion system will be described. Since the aromatic vinyl polymer block (A) having an ion conductive group is hydrophilic and the aliphatic vinyl polymer block (B) is hydrophobic, it has a protective colloid forming ability, and a surfactant is used. An emulsion can be obtained without any problems. Further, by using a polar solvent such as water, particles having an ion conductive group having a high polarity in the outer shell can be easily produced.
　上記乳化液を作成する方法としては公知の方法を用いることができるが、分散粒径の分布を狭くできる点で転相乳化法を応用するのが好ましい。即ち、該ブロックポリマーを適当な有機溶剤に溶解した液を乳化機などで攪拌しながら水等の極性溶剤を加えていく。初期は有機溶剤系の中に水などの極性溶剤が粒子として分散している状態にあるが、極性溶剤がある量を超えると共連続状態となり、急激に粘度が上昇する。さらに極性溶剤を添加すると極性溶剤が連続相、有機溶媒が微粒子となり、粘度は急激に低下する。この方法を用いることで、分散粒径の揃った乳化液を得ることができる。 Although a known method can be used as a method for preparing the emulsion, it is preferable to apply the phase inversion emulsification method in that the distribution of the dispersed particle diameter can be narrowed. That is, a polar solvent such as water is added while stirring a solution obtained by dissolving the block polymer in a suitable organic solvent with an emulsifier. Initially, a polar solvent such as water is dispersed in the organic solvent system as particles, but when the polar solvent exceeds a certain amount, it becomes a co-continuous state, and the viscosity rapidly increases. Further, when a polar solvent is added, the polar solvent becomes a continuous phase and the organic solvent becomes fine particles, and the viscosity rapidly decreases. By using this method, an emulsion having a uniform dispersed particle size can be obtained.
　乳化液の分散粒径が１μｍを超える大粒径である場合、粒子内でブロックポリマーが相分離した構造となり、全てのイオン伝導性基が外殻に出てきていないため、イオン伝導性基を有効に使用することができない。したがって、ブロックポリマーを用いる場合には用いるポリマーの分子量やブロックの比率にもよるが、平均分散粒径が１μｍ以下になるまで微粒子化するのが望ましい。多くの場合、上記プレ乳化での平均分散粒径は１μｍ以上となるため、さらなる微分散化が必要となる。微分散化の手法としては公知の方法を用いることができるが、不純物混入防止の観点でボールミルにおける粉砕用のボールのようなメディアを使用しない方法が好ましい。具体例としては高圧衝突法などが挙げられる。 When the dispersion particle size of the emulsion is larger than 1 μm, the block polymer has a phase-separated structure within the particle, and not all ion conductive groups have come out in the outer shell. It cannot be used effectively. Therefore, when a block polymer is used, it is desirable to make fine particles until the average dispersed particle size is 1 μm or less, depending on the molecular weight of the polymer used and the block ratio. In many cases, since the average dispersed particle size in the pre-emulsification is 1 μm or more, further fine dispersion is required. As a fine dispersion method, a known method can be used, but a method that does not use a medium such as a ball for grinding in a ball mill is preferable from the viewpoint of preventing impurities from being mixed. Specific examples include a high-pressure collision method.
　また、溶液塗工方法における溶媒除去の条件は、ブロック共重合体のスルホン酸基等のイオン伝導性基が脱落する温度以下で、溶媒を完全に除去できる条件であれば任意に選択することが可能である。所望の物性を発現させるため、複数の温度を任意に組み合わせたり、通風気下と真空下等を任意に組み合わせてもよい。具体的には、６０～１００℃程度の熱風乾燥にて４分以上かけて溶媒を除去する方法や、１００～１４０℃程度の熱風乾燥にて２～４分にて溶媒を除去する方法や、２５℃程度で１～３時間程度、予備乾燥させた後、１００℃程度の熱風乾燥にて数分かけて乾燥する方法や、２５℃程度で１～３時間程度、予備乾燥させた後、２５～４０℃程度の雰囲気下、真空乾燥にて１～１２時間程度乾燥する方法などが挙げられる。良好な強度と柔軟性を有する高分子電解質膜を調製しやすい観点から、６０～１００℃程度の熱風乾燥にて４分以上かけて溶媒を除去する方法や、２５℃程度で１～３時間程度、予備乾燥させた後、１００℃程度の熱風乾燥にて数分かけて乾燥する方法や、２５℃程度で１～３時間程度、予備乾燥させた後、２５～４０℃程度の雰囲気下、真空乾燥にて１～１２時間程度乾燥する方法などが好適に用いられる。 In addition, the solvent removal conditions in the solution coating method may be arbitrarily selected as long as the conditions are such that the solvent can be completely removed at a temperature equal to or lower than the temperature at which ion conductive groups such as sulfonic acid groups of the block copolymer are removed. Is possible. In order to express desired physical properties, a plurality of temperatures may be arbitrarily combined, or a combination of ventilation and vacuum may be arbitrarily combined. Specifically, a method of removing the solvent by hot air drying at about 60 to 100 ° C. over 4 minutes, a method of removing the solvent in 2 to 4 minutes by hot air drying at about 100 to 140 ° C., After preliminarily drying at about 25 ° C. for about 1 to 3 hours and then drying with hot air drying at about 100 ° C. for several minutes, or after preliminary drying at about 25 ° C. for about 1 to 3 hours, 25 Examples include a method of drying for about 1 to 12 hours by vacuum drying under an atmosphere of about 40 ° C. From the viewpoint of easy preparation of a polymer electrolyte membrane having good strength and flexibility, a method of removing the solvent by hot air drying at about 60 to 100 ° C. over 4 minutes, or about 1 to 3 hours at about 25 ° C. Then, after pre-drying, dry with hot air drying at about 100 ° C. over several minutes, or after pre-drying at about 25 ° C. for about 1 to 3 hours and then in an atmosphere at about 25-40 ° C. under vacuum A method of drying for about 1 to 12 hours by drying is preferably used.
　次に、本発明の高分子電解質より作製した高分子電解質膜を用いた本発明の膜－電極接合体について述べる。膜－電極接合体の製造については特に制限はなく、公知の方法を適用することができ、例えば、イオン伝導性バインダーを含む触媒ペーストを印刷法やスプレー法により、ガス拡散層上に塗布し乾燥することで触媒層とガス拡散層との接合体を形成させ、ついで１対の接合体をそれぞれ触媒層を内側にして、高分子電解質膜の両側にホットプレスなどにより接合させる方法や、上記触媒ペーストを印刷法やスプレー法により高分子電解質の両側に塗布し、乾燥して触媒層を形成させ、それぞれの触媒層に、ホットプレスなどによりガス拡散層を圧着させる方法がある。さらに別の製造方法として、イオン伝導性バインダーを含む溶液又は懸濁液を、高分子電解質膜の両面及び／又は１対のガス拡散電極の触媒層面に塗布し、高分子電解質膜と触媒層面とを張り合わせ、熱圧着などにより接合させる方法がある。この場合、該溶液又は懸濁液は高分子電解質膜及び触媒層面のいずれか一方に塗付してもよいし、両方に塗付してもよい。さらに他の製造方法として、まず、上記触媒ペーストをポリテトラフルオロエチレン（ＰＴＦＥ）製などの基材フィルムに塗布し、乾燥して触媒層を形成させ、ついで、１対のこの基材フィルム上の触媒層を高分子電解質膜の両側に加熱圧着により転写し、基材フィルムを剥離することで高分子電解質膜と触媒層との接合体を得、それぞれの触媒層にホットプレスによりガス拡散層を圧着する方法がある。これらの方法においては、イオン伝導性基をＮａなどの金属との塩にした状態で行い、接合後の酸処理によってプロトン型に戻す処理を行ってもよい。 Next, the membrane-electrode assembly of the present invention using a polymer electrolyte membrane produced from the polymer electrolyte of the present invention will be described. There is no particular limitation on the production of the membrane-electrode assembly, and a known method can be applied. For example, a catalyst paste containing an ion conductive binder is applied on the gas diffusion layer by a printing method or a spray method and dried. Forming a joined body of the catalyst layer and the gas diffusion layer, and then joining the pair of joined bodies to each side of the polymer electrolyte membrane by hot pressing or the like with the catalyst layer inside, or the catalyst There is a method in which a paste is applied to both sides of a polymer electrolyte by a printing method or a spray method, dried to form a catalyst layer, and a gas diffusion layer is pressure-bonded to each catalyst layer by hot pressing or the like. As yet another production method, a solution or suspension containing an ion conductive binder is applied to both surfaces of the polymer electrolyte membrane and / or the catalyst layer surface of a pair of gas diffusion electrodes, and the polymer electrolyte membrane and the catalyst layer surface There is a method of bonding them together by thermocompression bonding. In this case, the solution or suspension may be applied to one or both of the polymer electrolyte membrane and the catalyst layer surface. As another manufacturing method, first, the catalyst paste is applied to a base film made of polytetrafluoroethylene (PTFE) and dried to form a catalyst layer, and then a pair of base films on the base film is formed. The catalyst layer is transferred to both sides of the polymer electrolyte membrane by thermocompression bonding, and the base film is peeled off to obtain a joined body of the polymer electrolyte membrane and the catalyst layer. A gas diffusion layer is formed on each catalyst layer by hot pressing. There is a method of crimping. In these methods, an ion conductive group may be in a salt state with a metal such as Na, and a treatment for returning to a proton type by acid treatment after bonding may be performed.
　上記膜－電極接合体を構成するイオン伝導性バインダーとしては、例えば、「Ｎａｆｉｏｎ」（登録商標、デュポン社製）や「Ｇｏｒｅ－ｓｅｌｅｃｔ」（登録商標、ゴア社製）などの既存のパーフルオロスルホン酸系ポリマーからなるイオン伝導性バインダー、スルホン化ポリエーテルスルホンやスルホン化ポリエーテルケトンからなるイオン伝導性バインダー、リン酸や硫酸を含浸したポリベンズイミダゾールからなるイオン伝導性バインダー等を用いることができる。また、本発明の高分子電解質膜を構成するブロック共重合体からイオン伝導性バインダーを作製してもよい。なお、高分子電解質膜とガス拡散電極との密着性を一層高めるためには、高分子電解質膜を構成する高分子電解質と同種の材料、より好ましくは同一の材料から形成したイオン伝導性バインダーを用いることが好ましい。高分子電解質膜が複層構造など複数の材料からなる場合、高分子電解質膜のガス拡散電極と接する面を構成する高分子電解質、または該面の主たる構成成分である高分子電解質と同種の材料、より好ましくは同一の材料から形成したイオン伝導性バインダーを用いることが好ましい。 Examples of the ion conductive binder constituting the membrane-electrode assembly include existing perfluorosulfones such as “Nafion” (registered trademark, manufactured by DuPont) and “Gore-select” (registered trademark, manufactured by Gore). An ion conductive binder made of an acid polymer, an ion conductive binder made of a sulfonated polyethersulfone or a sulfonated polyetherketone, an ion conductive binder made of polybenzimidazole impregnated with phosphoric acid or sulfuric acid can be used. . Moreover, you may produce an ion conductive binder from the block copolymer which comprises the polymer electrolyte membrane of this invention. In order to further improve the adhesion between the polymer electrolyte membrane and the gas diffusion electrode, an ion conductive binder formed of the same material as the polymer electrolyte constituting the polymer electrolyte membrane, more preferably the same material, is used. It is preferable to use it. When the polymer electrolyte membrane is composed of a plurality of materials such as a multilayer structure, the polymer electrolyte constituting the surface in contact with the gas diffusion electrode of the polymer electrolyte membrane, or the same type of material as the polymer electrolyte that is the main component of the surface More preferably, an ion conductive binder formed from the same material is used.
　上記膜－電極接合体の触媒層の構成材料について、導電材／触媒担体としては特に制限はなく、例えば炭素材料が挙げられる。炭素材料としては、例えば、ファーネスブラック、チャンネルブラック、アセチレンブラック等のカーボンブラック、活性炭、黒鉛などが挙げられ、これら単独であるいは２種以上混合して使用される。触媒金属としては、水素やメタノールなどの燃料の酸化反応及び酸素の還元反応を促進する金属であればいずれのものでもよく、例えば、白金、金、銀、パラジウム、イリジウム、ロジウム、ルテニウム、鉄、コバルト、ニッケル、クロム、タングステン、マンガン、パラジウム等、あるいはそれらの合金、例えば白金－ルテニウム合金が挙げられる。中でも白金や白金合金が多くの場合用いられる。触媒となる金属の粒径は、通常は、１０～３００オングストロームである。これら触媒はカーボン等の導電材／触媒担体に担持させた方が触媒使用量は少なくコスト的に有利である。また、触媒層には、必要に応じて撥水剤が含まれていてもよい。撥水剤としては例えばポリテトラフルオロエチレン、ポリフッ化ビニリデン、スチレンブタジエン共重合体、ポリエーテルエーテルケトン等の各種熱可塑性樹脂が挙げられる。 The constituent material of the catalyst layer of the membrane-electrode assembly is not particularly limited as the conductive material / catalyst support, and examples thereof include carbon materials. Examples of the carbon material include carbon black such as furnace black, channel black, and acetylene black, activated carbon, graphite, and the like. These may be used alone or in combination of two or more. The catalyst metal may be any metal that promotes the oxidation reaction of fuel such as hydrogen or methanol and the reduction reaction of oxygen, such as platinum, gold, silver, palladium, iridium, rhodium, ruthenium, iron, Cobalt, nickel, chromium, tungsten, manganese, palladium, etc., or alloys thereof, for example, platinum-ruthenium alloy can be mentioned. Of these, platinum and platinum alloys are often used. The particle size of the metal serving as a catalyst is usually 10 to 300 angstroms. When these catalysts are supported on a conductive material such as carbon / catalyst support, the amount of catalyst used is small and it is advantageous in terms of cost. The catalyst layer may contain a water repellent as necessary. Examples of the water repellent include various thermoplastic resins such as polytetrafluoroethylene, polyvinylidene fluoride, styrene butadiene copolymer, and polyether ether ketone.
　上記膜－電極接合体のガス拡散層は、導電性及びガス透過性を備えた材料から構成され、かかる材料として例えばカーボンペーパーやカーボンクロス等の炭素繊維よりなる多孔性材料が挙げられる。また、かかる材料には、撥水性を向上させるために、撥水化処理を施してもよい。 The gas diffusion layer of the membrane-electrode assembly is made of a material having conductivity and gas permeability, and examples of such a material include porous materials made of carbon fibers such as carbon paper and carbon cloth. Moreover, in order to improve water repellency, this material may be subjected to water repellency treatment.
　上記のような方法で得られた膜－電極接合体を、極室分離と電極へのガス供給流路の役割を兼ねた導電性のセパレータ材の間に挿入することにより、固体高分子型燃料電池が得られる。本発明の膜－電極接合体は、燃料ガスとして水素を使用した純水素型、メタノールを改質して得られる水素を使用したメタノール改質型、天然ガスを改質して得られる水素を使用した天然ガス改質型、ガソリンを改質して得られる水素を使用したガソリン改質型、メタノールを直接使用する直接メタノール型等の固体高分子型燃料電池用膜－電極接合体として使用可能である。 By inserting the membrane-electrode assembly obtained by the method as described above between the conductive separator material that also serves as a gas supply flow path to the electrode separation and the electrode, a solid polymer fuel A battery is obtained. The membrane-electrode assembly of the present invention uses a pure hydrogen type using hydrogen as a fuel gas, a methanol reforming type using hydrogen obtained by reforming methanol, and hydrogen obtained by reforming natural gas. Natural gas reforming type, gasoline reforming type using hydrogen obtained by reforming gasoline, direct methanol type using methanol directly, etc. is there.
　本発明の高分子電解質からなる高分子電解質膜は、低湿度下における高いプロトン伝導性を有し、低抵抗を示し、該高分子電解質膜を含んでなる膜－電極接合体は水素を燃料とする固体高分子型燃料電池に用いることで、低湿度下においても高い出力特性を得ることが可能であり、また、水による膨潤が少なく、電極との接合性にも優れる。 The polymer electrolyte membrane comprising the polymer electrolyte of the present invention has high proton conductivity at low humidity and low resistance, and the membrane-electrode assembly comprising the polymer electrolyte membrane uses hydrogen as a fuel. When used in a polymer electrolyte fuel cell, it is possible to obtain high output characteristics even under low humidity, and there is little swelling due to water and excellent bondability with electrodes.
　以下、実施例及び比較例を挙げて本発明をさらに具体的に説明するが、本発明はこれらの実施例により限定されるものではない。 Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
（ブロック共重合体のイオン交換容量の測定方法）
　試料を密閉できるガラス容器中にブロック共重合体を秤量（秤量値ａ（ｇ））し、過剰量の塩化ナトリウム飽和水溶液（（３００～５００）×ａ（ｍｌ））を添加して１２時間攪拌した。フェノールフタレインを指示薬として、水中に発生した塩化水素を０．０１規定のＮａＯＨ標準水溶液（力価ｆ）にて滴定（滴定量ｂ（ｍｌ））した。
　イオン交換容量は次式により求めた。
イオン交換容量（ｍｅｑ／ｇ）＝（０．０１×ｂ×ｆ）／ａ (Measurement method of ion exchange capacity of block copolymer)
Weigh the block copolymer (weighing value a (g)) in a glass container that can seal the sample, add an excess amount of a saturated aqueous sodium chloride solution ((300 to 500) × a (ml)), and stir for 12 hours. did. Using phenolphthalein as an indicator, hydrogen chloride generated in water was titrated (a titration b (ml)) with a 0.01 N NaOH standard aqueous solution (titer f).
The ion exchange capacity was determined by the following formula.
Ion exchange capacity (meq / g) = (0.01 × b × f) / a
（ブロック共重合体の数平均分子量の測定方法）
　数平均分子量はゲルパーミエーションクロマトグラフィー（ＧＰＣ）法により下記の条件で測定した。
　　装置：東ソー（株）製、商品名：ＨＬＣ－８２２０ＧＰＣ
　　溶離液：ＴＨＦ
　　カラム：東ソー（株）製、商品名：ＴＳＫ－ＧＥＬ（ＴＳＫｇｅｌ　Ｇ３０００ＨｘＬ（内径７．６ｍｍ、有効長３０ｃｍ）を１本、ＴＳＫｇｅｌ　Ｓｕｐｅｒ　Ｍｕｌｔｉｐｏｒｅ　ＨＺ－Ｍ（内径４．６ｍｍ、有効長１５ｃｍ）を２本の計３本を直列で接続）
　　カラム温度：４０℃
　　検出器：ＲＩ
　　送液量：０．３５ｍｌ／分
　　数平均分子量計算：標準ポリスチレン換算 (Method for measuring the number average molecular weight of the block copolymer)
The number average molecular weight was measured by the gel permeation chromatography (GPC) method under the following conditions.
Device: manufactured by Tosoh Corporation, trade name: HLC-8220GPC
Eluent: THF
Column: manufactured by Tosoh Corporation, trade name: 1 TSK-GEL (TSKgel G3000HxL (inner diameter 7.6 mm, effective length 30 cm)), TSKgel Super Multipore HZ-M (inner diameter 4.6 mm, effective length 15 cm) 3 in total)
Column temperature: 40 ° C
Detector: RI
Liquid feed amount: 0.35 ml / min Number average molecular weight calculation: Standard polystyrene conversion
＜参考例１＞
（ポリ（４－ビニルビフェニル）、水添ポリイソプレン及びポリ（４－ｔｅｒｔ－ブチルスチレン）からなるブロック共重合体の製造）
　１０００ｍＬオートクレーブに、脱水トルエン４３５ｍｌ及びｓｅｃ－ブチルリチウム（１．０５Ｍ－シクロヘキサン溶液）１．７１ｍｌを仕込んだ後、４－ｔｅｒｔ－ブチルスチレン７．６ｍｌ、４－ビニルビフェニル２５．３ｇ、４－ｔｅｒｔ－ブチルスチレン７．１ｍｌ、イソプレン２６．４ｍｌ、４－ｔｅｒｔ－ブチルスチレン６．６ｍｌを逐次添加し、４０℃で逐次重合させることにより、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリ（４－ビニルビフェニル）－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリイソプレン－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＶＢｔＢＳＩｔＢＳと略記する）を合成した。得られたｔＢＳＶＢｔＢＳＩｔＢＳの数平均分子量（ＧＰＣ測定、標準ポリスチレン換算）は３５，０００であり、1Ｈ－ＮＭＲ測定から求めた１，４－結合量は９３．０％、４－ビニルビフェニル単位の含有量は３６．６重量％、４－ｔｅｒｔ－ブチルスチレン単位の含有量は３０．４重量％であった。 <Reference Example 1>
(Production of block copolymer comprising poly (4-vinylbiphenyl), hydrogenated polyisoprene and poly (4-tert-butylstyrene))
A 1000 mL autoclave was charged with 435 ml of dehydrated toluene and 1.71 ml of sec-butyllithium (1.05 M-cyclohexane solution), and then 7.6 ml of 4-tert-butylstyrene, 25.3 g of 4-vinylbiphenyl, 4-tert- By sequentially adding 7.1 ml of butylstyrene, 26.4 ml of isoprene, and 6.6 ml of 4-tert-butylstyrene, and successively polymerizing at 40 ° C., poly (4-tert-butylstyrene) -b-poly (4- Vinylbiphenyl) -b-poly (4-tert-butylstyrene) -b-polyisoprene-b-poly (4-tert-butylstyrene) (hereinafter abbreviated as tBSVBtBSItBS) was synthesized. The number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSVBtBSItBS is 35,000, the 1,4-bond amount determined from 1 H-NMR measurement is 93.0%, and the content of 4-vinylbiphenyl units is included. The amount was 36.6% by weight, and the content of 4-tert-butylstyrene units was 30.4% by weight.
　合成したｔＢＳＶＢｔＢＳＩｔＢＳのシクロヘキサン溶液を調製し、十分に窒素置換を行った耐圧容器に仕込んだ後、Ｎｉ／Ａｌ系のＺｉｅｇｌｅｒ系水素添加触媒を用いて、水素雰囲気下において７０℃で８時間水素添加反応を行い、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリ（４－ビニルビフェニル）－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－水添ポリイソプレン－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＶＢｔＢＳＥＰｔＢＳと略記する）を得た。得られたｔＢＳＶＢｔＢＳＥＰｔＢＳの水素添加率を1Ｈ－ＮＭＲスペクトル測定により算出したところ、ポリイソプレンの二重結合に由来するピークは検出されなかった。 A cyclohexane solution of synthesized tBSVBtBSItBS was prepared and charged into a pressure-resistant vessel that had been sufficiently purged with nitrogen. Then, a hydrogenation reaction was performed at 70 ° C. for 8 hours in a hydrogen atmosphere using a Ni / Al Ziegler hydrogenation catalyst. Poly (4-tert-butylstyrene) -b-poly (4-vinylbiphenyl) -b-poly (4-tert-butylstyrene) -b-hydrogenated polyisoprene-b-poly (4-tert- Butylstyrene) (hereinafter abbreviated as tBSVBtBSEPtBS). When the hydrogenation rate of the obtained tBSVBtBSEPtBS was calculated by 1 H-NMR spectrum measurement, no peak derived from the polyisoprene double bond was detected.
＜参考例２＞
（ポリ（４－ビニルビフェニル）、水添ポリイソプレン及びポリ（４－ｔｅｒｔ－ブチルスチレン）からなるブロック共重合体の製造）
　１０００ｍＬオートクレーブに、脱水トルエン４３５ｍｌ及びｓｅｃ－ブチルリチウム（１．２０Ｍ－シクロヘキサン溶液）１．０ｍｌを仕込んだ後、４－ｔｅｒｔ－ブチルスチレン１０．３ｍｌ、４－ビニルビフェニル２２．８ｇ、イソプレン３６．８ｍｌを添加し、４０℃で重合させ、安息香酸フェニル１３７ｍｇを添加し、カップリングさせることにより、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリ（４－ビニルビフェニル）－ｂ－ポリイソプレン－ｂ－ポリ（４－ビニルビフェニル）－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＶＢＩＶＢｔＢＳと略記する）を合成した。得られたｔＢＳＶＢＩＶＢｔＢＳの数平均分子量（ＧＰＣ測定、標準ポリスチレン換算）は１５８，０００であり、1Ｈ－ＮＭＲ測定から求めた１，４－結合量は９４．０％、４－ビニルビフェニル単位の含有量は３３．９重量％、４－ｔｅｒｔ－ブチルスチレン単位の含有量は２２．０重量％であった。 <Reference Example 2>
(Production of block copolymer comprising poly (4-vinylbiphenyl), hydrogenated polyisoprene and poly (4-tert-butylstyrene))
A 1000 mL autoclave was charged with 435 ml of dehydrated toluene and 1.0 ml of sec-butyllithium (1.20 M-cyclohexane solution), and then 10.3 ml of 4-tert-butylstyrene, 22.8 g of 4-vinylbiphenyl, and 36.8 ml of isoprene. Is added, polymerized at 40 ° C., 137 mg of phenyl benzoate is added and coupled to give poly (4-tert-butylstyrene) -b-poly (4-vinylbiphenyl) -b-polyisoprene-b -Poly (4-vinylbiphenyl) -b-poly (4-tert-butylstyrene) (hereinafter abbreviated as tBSVBIVBtBS) was synthesized. The number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSVBIVBtBS is 158,000, the 1,4-bond amount determined from 1 H-NMR measurement is 94.0%, and the content of 4-vinylbiphenyl units The amount was 33.9% by weight, and the content of 4-tert-butylstyrene units was 22.0% by weight.
　合成したｔＢＳＶＢＩＶＢｔＢＳのシクロヘキサン溶液を調製し、十分に窒素置換を行った耐圧容器に仕込んだ後、Ｎｉ／Ａｌ系のＺｉｅｇｌｅｒ系水素添加触媒を用いて、水素雰囲気下において７０℃で８時間水素添加反応を行い、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリ（４－ビニルビフェニル）－ｂ－水添ポリイソプレン－ｂ－ポリ（４－ビニルビフェニル）－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＶＢＥＰＶＢｔＢＳと略記する）を得た。得られたｔＢＳＶＢＥＰＶＢｔＢＳの水素添加率を1Ｈ－ＮＭＲスペクトル測定により算出したところ、ポリイソプレンの二重結合に由来するピークは検出されなかった。 A cyclohexane solution of synthesized tBSVBIVBtBS was prepared and charged into a pressure-resistant vessel that had been fully purged with nitrogen. Then, a hydrogenation reaction was performed at 70 ° C. for 8 hours in a hydrogen atmosphere using a Ni / Al Ziegler hydrogenation catalyst. Poly (4-tert-butylstyrene) -b-poly (4-vinylbiphenyl) -b-hydrogenated polyisoprene-b-poly (4-vinylbiphenyl) -b-poly (4-tert-butylstyrene) (Hereinafter abbreviated as tBSVBEPVBtBS). When the hydrogenation rate of the obtained tBSVBEPVBtBS was calculated by 1 H-NMR spectrum measurement, no peak derived from the polyisoprene double bond was detected.
＜参考例３＞
（ポリスチレン、水添ポリイソプレン及びポリ（４－ｔｅｒｔ－ブチルスチレン））からなるブロック共重合体の製造）
　１４００ｍＬオートクレーブに、脱水シクロヘキサン８２０ｍｌ及びｓｅｃ－ブチルリチウム（１．２５Ｍ－シクロヘキサン溶液）１．７ｍｌを仕込んだ後、４－ｔｅｒｔ－ブチルスチレン１９．８ｍｌ、スチレン２７．７ｍｌを逐次添加し、５０℃で逐次重合させ、次いでイソプレン８０．４ｍｌ、スチレン２６．６ｍｌ、及び４－ｔｅｒｔ－ブチルスチレン１８．１ｍｌを逐次添加し、６０℃で逐次重合させることにより、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリスチレン－ｂ－ポリイソプレン－ｂ－ポリスチレン－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＳＩＳｔＢＳと略記する）を合成した。得られたｔＢＳＳＩＳｔＢＳの数平均分子量（ＧＰＣ測定、標準ポリスチレン換算）は８６，０００であり、1Ｈ－ＮＭＲ測定から求めた１，４－結合量は９４．０％、スチレン単位の含有量は３２．９重量％、４－ｔｅｒｔ－ブチルスチレン単位の含有量は２９．８重量％であった。 <Reference Example 3>
(Production of block copolymer consisting of polystyrene, hydrogenated polyisoprene and poly (4-tert-butylstyrene))
Into a 1400 mL autoclave, 820 ml of dehydrated cyclohexane and 1.7 ml of sec-butyllithium (1.25 M-cyclohexane solution) were charged, and then 19.8 ml of 4-tert-butylstyrene and 27.7 ml of styrene were successively added at 50 ° C. Poly (4-tert-butylstyrene) -b by sequential polymerization and then sequential addition of 80.4 ml of isoprene, 26.6 ml of styrene and 18.1 ml of 4-tert-butylstyrene and successive polymerization at 60 ° C. -Polystyrene-b-polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene) (hereinafter abbreviated as tBSSIStBS) was synthesized. The number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSSIStBS was 86,000, the 1,4-bond content determined from 1 H-NMR measurement was 94.0%, and the styrene unit content was 32. The content of 9.9% by weight and 4-tert-butylstyrene unit was 29.8% by weight.
　合成したｔＢＳＳＩＳｔＢＳのシクロヘキサン溶液を調製し、十分に窒素置換を行った耐圧容器に仕込んだ後、Ｎｉ／Ａｌ系のＺｉｅｇｌｅｒ系水素添加触媒を用いて、水素雰囲気下において７０℃で８時間水素添加反応を行い、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリスチレン－ｂ－水添ポリイソプレン－ｂ－ポリスチレン－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＳＥＰＳｔＢＳと略記する）を得た。得られたｔＢＳＳＥＰＳｔＢＳの水素添加率を1Ｈ－ＮＭＲスペクトル測定により算出したところ、ポリイソプレンの二重結合に由来するピークは検出されなかった。 After preparing a cyclohexane solution of the synthesized tBSSIStBS and charging it in a pressure vessel sufficiently purged with nitrogen, a hydrogenation reaction was performed at 70 ° C. for 8 hours in a hydrogen atmosphere using a Ni / Al Ziegler hydrogenation catalyst. To obtain poly (4-tert-butylstyrene) -b-polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene) (hereinafter abbreviated as tBSSEPStBS). . When the hydrogenation rate of the obtained tBSSEPStBS was calculated by 1 H-NMR spectrum measurement, no peak derived from the polyisoprene double bond was detected.
＜参考例４＞
（ポリスチレン、水添ポリイソプレン及びポリ（４－ｔｅｒｔ－ブチルスチレン）からなるブロック共重合体の製造）
　１４００ｍＬオートクレーブに、脱水シクロヘキサン７６８ｍｌ及びｓｅｃ－ブチルリチウム（１．２５Ｍ－シクロヘキサン溶液）１．７６ｍｌを仕込んだ後、４－ｔｅｒｔ－ブチルスチレン６０．７ｍｌ、スチレン５５．６ｍｌを逐次添加し、５０℃で逐次重合させ、次いでイソプレン２０２ｍｌ、スチレン５４．１ｍｌ、及び４－ｔｅｒｔ－ブチルスチレン５６．７ｍｌを逐次添加し、６０℃で逐次重合させることにより、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリスチレン－ｂ－ポリイソプレン－ｂ－ポリスチレン－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＳＩＳｔＢＳと略記する）を合成した。得られたｔＢＳＳＩＳｔＢＳの数平均分子量（ＧＰＣ測定、標準ポリスチレン換算）は７２，０００であり、1Ｈ－ＮＭＲ測定から求めた１，４－結合量は９４．０％、スチレン単位の含有量は２９．４重量％、４－ｔｅｒｔ－ブチルスチレン単位の含有量は３０．０重量％であった。 <Reference Example 4>
(Production of block copolymer consisting of polystyrene, hydrogenated polyisoprene and poly (4-tert-butylstyrene))
A 1400 mL autoclave was charged with 768 ml of dehydrated cyclohexane and 1.76 ml of sec-butyllithium (1.25 M-cyclohexane solution), and then 60.7 ml of 4-tert-butylstyrene and 55.6 ml of styrene were successively added at 50 ° C. Poly (4-tert-butylstyrene) -b-polystyrene by sequential polymerization followed by sequential addition of 202 ml of isoprene, 54.1 ml of styrene and 56.7 ml of 4-tert-butylstyrene and sequential polymerization at 60 ° C. -B-polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene) (hereinafter abbreviated as tBSSIStBS) was synthesized. The number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSSIStBS was 72,000, the 1,4-bond amount determined from 1 H-NMR measurement was 94.0%, and the styrene unit content was 29. The content of 4% by weight and 4-tert-butylstyrene unit was 30.0% by weight.
　合成したｔＢＳＳＩＳｔＢＳのシクロヘキサン溶液を調製し、十分に窒素置換を行った耐圧容器に仕込んだ後、Ｎｉ／Ａｌ系のＺｉｅｇｌｅｒ系水素添加触媒を用いて、水素雰囲気下において７０℃で８時間水素添加反応を行い、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリスチレン－ｂ－水添ポリイソプレン－ｂ－ポリスチレン－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＳＥＰＳｔＢＳと略記する）を得た。得られたｔＢＳＳＥＰＳｔＢＳの水素添加率を1Ｈ－ＮＭＲスペクトル測定により算出したところ、ポリイソプレンの二重結合に由来するピークは検出されなかった。 After preparing a cyclohexane solution of the synthesized tBSSIStBS and charging it in a pressure vessel sufficiently purged with nitrogen, a hydrogenation reaction was performed at 70 ° C. for 8 hours in a hydrogen atmosphere using a Ni / Al Ziegler hydrogenation catalyst. To obtain poly (4-tert-butylstyrene) -b-polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene) (hereinafter abbreviated as tBSSEPStBS). . When the hydrogenation rate of the obtained tBSSEPStBS was calculated by 1 H-NMR spectrum measurement, no peak derived from the polyisoprene double bond was detected.
＜参考例５＞
（ポリスチレン、水添ポリイソプレン及びポリ（４－ｔｅｒｔ－ブチルスチレン））からなるブロック共重合体の製造）
　１４００ｍＬオートクレーブに、脱水シクロヘキサン５９３ｍｌ及びｓｅｃ－ブチルリチウム（１．００Ｍ－シクロヘキサン溶液）２．９ｍｌを仕込んだ後、４－ｔｅｒｔ－ブチルスチレン２２．９ｍｌ、スチレン３２．６ｍｌを逐次添加し、５０℃で逐次重合させ、次いでイソプレン５９．０ｍｌ、スチレン２９．３ｍｌ、及び４－ｔｅｒｔ－ブチルスチレン２０．３ｍｌを逐次添加し、６０℃で逐次重合させることにより、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリスチレン－ｂ－ポリイソプレン－ｂ－ポリスチレン－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＳＩＳｔＢＳと略記する）を合成した。得られたｔＢＳＳＩＳｔＢＳの数平均分子量（ＧＰＣ測定、標準ポリスチレン換算）は６４，０００であり、1Ｈ－ＮＭＲ測定から求めた１，４－結合量は９４．２％、スチレン単位の含有量は４１．２重量％、４－ｔｅｒｔ－ブチルスチレン単位の含有量は２９．４重量％であった。 <Reference Example 5>
(Production of block copolymer consisting of polystyrene, hydrogenated polyisoprene and poly (4-tert-butylstyrene))
In a 1400 mL autoclave, 593 ml of dehydrated cyclohexane and 2.9 ml of sec-butyllithium (1.00 M-cyclohexane solution) were charged, and then 22.9 ml of 4-tert-butylstyrene and 32.6 ml of styrene were successively added at 50 ° C. Poly (4-tert-butylstyrene) -b by sequential polymerization, followed by sequential addition of 59.0 ml of isoprene, 29.3 ml of styrene, and 20.3 ml of 4-tert-butylstyrene and sequential polymerization at 60 ° C. -Polystyrene-b-polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene) (hereinafter abbreviated as tBSSIStBS) was synthesized. The number average molecular weight (GPC measurement, standard polystyrene conversion) of the obtained tBSSIStBS was 64,000, the 1,4-bond content determined from 1 H-NMR measurement was 94.2%, and the styrene unit content was 41. The content of 2-wt% and 4-tert-butylstyrene units was 29.4 wt%.
　合成したｔＢＳＳＩＳｔＢＳのシクロヘキサン溶液を調製し、十分に窒素置換を行った耐圧容器に仕込んだ後、Ｎｉ／Ａｌ系のＺｉｅｇｌｅｒ系水素添加触媒を用いて、水素雰囲気下において７０℃で８時間水素添加反応を行い、ポリ（４－ｔｅｒｔ－ブチルスチレン）－ｂ－ポリスチレン－ｂ－水添ポリイソプレン－ｂ－ポリスチレン－ｂ－ポリ（４－ｔｅｒｔ－ブチルスチレン）（以下、ｔＢＳＳＥＰＳｔＢＳと略記する）を得た。得られたｔＢＳＳＥＰＳｔＢＳの水素添加率を1Ｈ－ＮＭＲスペクトル測定により算出したところ、ポリイソプレンの二重結合に由来するピークは検出されなかった。 After preparing a cyclohexane solution of the synthesized tBSSIStBS and charging it in a pressure vessel sufficiently purged with nitrogen, a hydrogenation reaction was performed at 70 ° C. for 8 hours in a hydrogen atmosphere using a Ni / Al Ziegler hydrogenation catalyst. To obtain poly (4-tert-butylstyrene) -b-polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (4-tert-butylstyrene) (hereinafter abbreviated as tBSSEPStBS). . When the hydrogenation rate of the obtained tBSSEPStBS was calculated by 1 H-NMR spectrum measurement, no peak derived from the polyisoprene double bond was detected.
＜製造例１＞
（主としてスルホン化４－ビニルビフェニル単位からなる芳香族ビニル系重合体ブロック（Ａ）、主として水添イソプレン単位からなる脂肪族ビニル系重合体ブロック（Ｂ）及び主として４－ｔｅｒｔ－ブチルスチレンからなる芳香族ビニル系重合体ブロック（Ｃ）からなるブロック共重合体（スルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳ）の合成）
　参考例１で得られたブロック共重合体（ｔＢＳＶＢｔＢＳＥＰｔＢＳ）５ｇを、撹拌機付きのガラス製反応容器中にて１時間真空乾燥し、ついで窒素置換した後、塩化メチレン２００ｍｌを加え、室温にて攪拌して溶解させた。溶解後、塩化メチレン５０ｍｌ、クロロスルホン酸３．５ｍｌの混合溶液を、３０分かけて徐々に滴下した。室温にて４０時間攪拌後、停止剤としての蒸留水を１０ｍｌ添加した。その後、攪拌下、２５０ｍｌの蒸留水を重合体溶液にゆっくり注ぎ、重合体を凝固析出させた。塩化メチレンを常圧留去にて除去した後、ろ過した。ろ過により得られた固形分をビーカーに移し、蒸留水を１Ｌ添加して、攪拌下で洗浄を行った後、ろ過回収を行った。この洗浄及びろ過の操作を洗浄水のｐＨに変化がなくなるまで繰り返し、最後にろ集した重合体を真空乾燥して本発明の高分子電解質であるスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳを得た。得られたスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳのスルホン酸基を有する芳香族ビニル系重合体ブロック（Ａ）であるスルホン酸基変性した４－ビニルビフェニル単位を含む重合体ブロックの繰り返し単位あたりのスルホン酸基含有量は滴定から１．９６個であり、該高分子電解質のイオン交換容量は３．０ｍｅｑ／ｇであった。 <Production Example 1>
(Aromatic vinyl polymer block (A) mainly composed of sulfonated 4-vinylbiphenyl units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and aroma mainly composed of 4-tert-butylstyrene) Block copolymer consisting of aromatic vinyl polymer block (C) (synthesis of sulfonated tBSVBtBSEPtBS)
5 g of the block copolymer (tBSVBtBSEPtBS) obtained in Reference Example 1 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, followed by addition of 200 ml of methylene chloride and stirring at room temperature. And dissolved. After dissolution, a mixed solution of 50 ml of methylene chloride and 3.5 ml of chlorosulfonic acid was gradually added dropwise over 30 minutes. After stirring at room temperature for 40 hours, 10 ml of distilled water as a stopper was added. Thereafter, 250 ml of distilled water was slowly poured into the polymer solution with stirring to solidify and precipitate the polymer. The methylene chloride was removed by distillation at atmospheric pressure, followed by filtration. The solid content obtained by filtration was transferred to a beaker, 1 L of distilled water was added, washed with stirring, and then collected by filtration. This washing and filtration operation was repeated until there was no change in the pH of the washing water. Finally, the polymer collected by filtration was vacuum-dried to obtain a sulfonated tBSVBtBSEPtBS which is a polymer electrolyte of the present invention. The sulfonic acid group content per repeating unit of the polymer block containing 4-vinylbiphenyl unit modified with sulfonic acid group which is the aromatic vinyl polymer block (A) having sulfonic acid group of the obtained sulfonated tBSVBtBSEPtBS is The titration was 1.96, and the ion exchange capacity of the polymer electrolyte was 3.0 meq / g.
＜製造例２＞
（主としてスルホン化４－ビニルビフェニル単位からなる芳香族ビニル系重合体ブロック（Ａ）、主として水添イソプレン単位からなる脂肪族ビニル系重合体ブロック（Ｂ）及び主として４－ｔｅｒｔ－ブチルスチレン単位からなる芳香族ビニル系重合体ブロック（Ｃ）からなるブロック共重合体（スルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳ）の合成）
　参考例１で得られたブロック共重合体（ｔＢＳＶＢｔＢＳＥＰｔＢＳ）５ｇを、撹拌機付きのガラス製反応容器中にて１時間真空乾燥し、ついで窒素置換した後、塩化メチレン２００ｍｌを加え、室温にて攪拌して溶解させた。溶解後、塩化メチレン５０ｍｌ、クロロスルホン酸２．８ｍｌの混合溶液を、３０分かけて徐々に滴下した。室温にて７時間攪拌後、停止剤としての蒸留水を１０ｍｌ添加した。その後、攪拌下、２５０ｍｌの蒸留水を重合体溶液にゆっくり注ぎ、重合体を凝固析出させた。塩化メチレンを常圧留去にて除去した後、ろ過した。ろ過により得られた固形分をビーカーに移し、蒸留水を１Ｌ添加して、攪拌下で洗浄を行った後、ろ過回収を行った。この洗浄及びろ過の操作を洗浄水のｐＨに変化がなくなるまで繰り返し、最後にろ集した重合体を真空乾燥して本発明の高分子電解質であるスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳを得た。得られたスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳの芳香族ビニル系重合体ブロック（Ａ）であるスルホン酸基変性した４－ビニルビフェニル単位を含む重合体ブロックの繰り返し単位あたりのスルホン酸基含有量は滴定から１．７６個であり、該高分子電解質のイオン交換容量は２．７７ｍｅｑ／ｇであった。 <Production Example 2>
(Aromatic vinyl polymer block (A) mainly composed of sulfonated 4-vinylbiphenyl units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and mainly composed of 4-tert-butylstyrene units) Block copolymer composed of aromatic vinyl polymer block (C) (synthesis of sulfonated tBSVBtBSEPtBS)
5 g of the block copolymer (tBSVBtBSEPtBS) obtained in Reference Example 1 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, followed by addition of 200 ml of methylene chloride and stirring at room temperature. And dissolved. After dissolution, a mixed solution of 50 ml of methylene chloride and 2.8 ml of chlorosulfonic acid was gradually added dropwise over 30 minutes. After stirring for 7 hours at room temperature, 10 ml of distilled water as a stopper was added. Thereafter, 250 ml of distilled water was slowly poured into the polymer solution with stirring to solidify and precipitate the polymer. The methylene chloride was removed by distillation at atmospheric pressure, followed by filtration. The solid content obtained by filtration was transferred to a beaker, 1 L of distilled water was added, washed with stirring, and then collected by filtration. This washing and filtration operation was repeated until there was no change in the pH of the washing water. Finally, the polymer collected by filtration was vacuum-dried to obtain a sulfonated tBSVBtBSEPtBS which is a polymer electrolyte of the present invention. The content of sulfonic acid group per repeating unit of the polymer block containing 4-vinylbiphenyl unit modified with sulfonic acid group, which is the aromatic vinyl polymer block (A) of the obtained sulfonated tBSVBtBSEPtBS, was 1.76 from titration. The ion exchange capacity of the polymer electrolyte was 2.77 meq / g.
＜製造例３＞
（主としてスルホン化４－ビニルビフェニル単位からなる芳香族ビニル系重合体ブロック（Ａ）、主として水添イソプレン単位からなる脂肪族ビニル系重合体ブロック（Ｂ）及び主として４－ｔｅｒｔ－ブチルスチレン単位からなる芳香族ビニル系重合体ブロック（Ｃ）からなるブロック共重合体（スルホン化ｔＢＳＶＢＥＰＶＢｔＢＳ）の合成）
　参考例２で得られたブロック共重合体（ｔＢＳＶＢＥＰＶＢｔＢＳ）５ｇを、撹拌機付きのガラス製反応容器中にて１時間真空乾燥し、ついで窒素置換した後、塩化メチレン１８０ｍｌを加え、室温にて攪拌して溶解させた。溶解後、塩化メチレン４０ｍｌ、クロロスルホン酸２．８ｍｌの混合溶液を、３０分かけて徐々に滴下した。室温にて４時間攪拌後、停止剤としての蒸留水を１０ｍｌ添加した。その後、攪拌下、２２０ｍｌの蒸留水を重合体溶液にゆっくり注ぎ、重合体を凝固析出させた。塩化メチレンを常圧留去にて除去した後、ろ過した。ろ過により得られた固形分をビーカーに移し、蒸留水を１Ｌ添加して、攪拌下で洗浄を行った後、ろ過回収を行った。この洗浄及びろ過の操作を洗浄水のｐＨに変化がなくなるまで繰り返し、最後にろ集した重合体を真空乾燥して本発明の高分子電解質であるスルホン化ｔＢＳＶＢＥＰＶＢｔＢＳを得た。得られたスルホン化ｔＢＳＶＢＥＰＶＢｔＢＳの芳香族ビニル系重合体ブロック（Ａ）であるスルホン酸基変性した４－ビニルビフェニル単位を含む重合体ブロックの繰り返し単位あたりのスルホン酸基含有量は滴定から１．５４個であり、該高分子電解質のイオン交換容量は２．３３ｍｅｑ／ｇであった。 <Production Example 3>
(Aromatic vinyl polymer block (A) mainly composed of sulfonated 4-vinylbiphenyl units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and mainly composed of 4-tert-butylstyrene units) Block copolymer composed of aromatic vinyl polymer block (C) (synthesis of sulfonated tBSVBEPVBtBS)
5 g of the block copolymer (tBSVBEPVBtBS) obtained in Reference Example 2 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, and then 180 ml of methylene chloride was added and stirred at room temperature. And dissolved. After dissolution, a mixed solution of 40 ml of methylene chloride and 2.8 ml of chlorosulfonic acid was gradually added dropwise over 30 minutes. After stirring for 4 hours at room temperature, 10 ml of distilled water as a stopper was added. Thereafter, 220 ml of distilled water was slowly poured into the polymer solution with stirring to solidify and precipitate the polymer. The methylene chloride was removed by distillation at atmospheric pressure, followed by filtration. The solid content obtained by filtration was transferred to a beaker, 1 L of distilled water was added, washed with stirring, and then collected by filtration. This washing and filtration operation was repeated until there was no change in the pH of the washing water. Finally, the polymer collected by filtration was vacuum-dried to obtain a sulfonated tBSVBEPVBtBS which is a polymer electrolyte of the present invention. The content of sulfonic acid group per repeating unit of the polymer block containing 4-vinylbiphenyl unit modified with sulfonic acid group, which is the aromatic vinyl polymer block (A) of the obtained sulfonated tBSVBEPVBtBS is 1.54 from titration. The ion exchange capacity of the polymer electrolyte was 2.33 meq / g.
＜製造例４＞
（主としてスルホン化スチレン単位からなる芳香族ビニル系重合体ブロック（Ａ）、主として水添イソプレン単位からなる脂肪族ビニル系重合体ブロック（Ｂ）及び主として４－ｔｅｒｔ－ブチルスチレン単位からなる芳香族ビニル系重合体ブロック（Ｃ）からなるブロック共重合体（スルホン化ｔＢＳＳＥＰＳｔＢＳ）の合成）
　参考例３で得られたブロック共重合体（ｔＢＳＳＥＰＳｔＢＳ）４０ｇを、攪拌機付きのガラス製反応容器中にて１時間真空乾燥し、ついで窒素置換した後、塩化メチレン５００ｍｌを加え、室温にて攪拌して溶解させた。溶解後、塩化メチレン１２３ｍｌ中、０℃にて無水酢酸６１．４ｍｌと硫酸２７．５ｍｌとを反応させて得られたスルホン化試薬を、５分かけて徐々に滴下した。室温にて７２時間攪拌後、停止剤の蒸留水を２０ｍｌ添加した。その後、０．７Ｌの蒸留水を重合体溶液にゆっくり注ぎ、重合体を凝固析出させた。塩化メチレンを常圧留去にて除去した後、ろ過した。ろ過により得られた固形分をビーカーに移し、蒸留水を１．３Ｌ添加して、攪拌下で洗浄を行った後、ろ過回収を行った。この洗浄及びろ過の操作を洗浄水のｐＨに変化がなくなるまで繰り返し、最後にろ集した重合体を真空乾燥して本発明に属しない高分子電解質であるスルホン化ｔＢＳＳＥＰＳｔＢＳを得た。得られたスルホン化ｔＢＳＳＥＰＳｔＢＳのスルホン酸基変性したスチレン単位を含む重合体ブロックの繰り返し単位あたりのスルホン酸基含有量は1Ｈ－ＮＭＲ分析から１．００個であり、該高分子電解質のイオン交換容量は２．５２ｍｅｑ／ｇであった。 <Production Example 4>
(Aromatic vinyl polymer block (A) mainly composed of sulfonated styrene units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and aromatic vinyl mainly composed of 4-tert-butylstyrene units) Block copolymer consisting of a polymer block (C) (synthesis of sulfonated tBSSEPStBS)
40 g of the block copolymer (tBSSEPStBS) obtained in Reference Example 3 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, and then 500 ml of methylene chloride was added and stirred at room temperature. And dissolved. After dissolution, a sulfonation reagent obtained by reacting 61.4 ml of acetic anhydride and 27.5 ml of sulfuric acid at 0 ° C. in 123 ml of methylene chloride was gradually added dropwise over 5 minutes. After stirring at room temperature for 72 hours, 20 ml of distilled water as a stopper was added. Thereafter, 0.7 L of distilled water was slowly poured into the polymer solution to coagulate and precipitate the polymer. The methylene chloride was removed by distillation at atmospheric pressure, followed by filtration. The solid content obtained by filtration was transferred to a beaker, 1.3 L of distilled water was added, and washing was performed with stirring, followed by filtration and recovery. This washing and filtration operation was repeated until there was no change in the pH of the washing water. Finally, the polymer collected by filtration was vacuum dried to obtain a sulfonated tBSSEPStBS, which is a polymer electrolyte not belonging to the present invention. The content of sulfonic acid group per repeating unit of the polymer block containing styrene group modified with sulfonic acid group of the obtained sulfonated tBSSEPStBS is 1.00 from 1 H-NMR analysis, and the ion exchange of the polymer electrolyte The capacity was 2.52 meq / g.
＜製造例５＞
（主としてスルホン化スチレン単位からなる芳香族ビニル系重合体ブロック（Ａ）、主として水添イソプレン単位からなる脂肪族ビニル系重合体ブロック（Ｂ）及び主として４－ｔｅｒｔ－ブチルスチレン単位からなる芳香族ビニル系重合体ブロック（Ｃ）からなるブロック共重合体（スルホン化ｔＢＳＳＥＰＳｔＢＳ）の合成）
　参考例３で得られたブロック共重合体（ｔＢＳＳＥＰＳｔＢＳ）４０ｇを、攪拌機付きのガラス製反応容器中にて１時間真空乾燥し、ついで窒素置換した後、塩化メチレン４５２ｍｌを加え、室温にて攪拌して溶解させた。溶解後、塩化メチレン１１１ｍｌ中、０℃にて無水酢酸５５．５ｍｌと硫酸２４．８ｍｌとを反応させて得られたスルホン化試薬を、５分かけて徐々に滴下した。室温にて７２時間攪拌後、停止剤の蒸留水を２０ｍｌ添加した。その後、０．７Ｌの蒸留水を重合体溶液にゆっくり注ぎ、重合体を凝固析出させた。塩化メチレンを常圧留去にて除去した後、ろ過した。ろ過により得られた固形分をビーカーに移し、蒸留水を１．３Ｌ添加して、攪拌下で洗浄を行った後、ろ過回収を行った。この洗浄及びろ過の操作を洗浄水のｐＨに変化がなくなるまで繰り返し、最後にろ集した重合体を真空乾燥して本発明に属しない高分子電解質であるスルホン化ｔＢＳＳＥＰＳｔＢＳを得た。得られたスルホン化ｔＢＳＳＥＰＳｔＢＳのスルホン酸基変性したスチレン単位を含む重合体ブロックの繰り返し単位あたりのスルホン酸基含有量は1Ｈ－ＮＭＲ分析から１．００個であり、該高分子電解質のイオン交換容量は２．３０ｍｅｑ／ｇであった。 <Production Example 5>
(Aromatic vinyl polymer block (A) mainly composed of sulfonated styrene units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and aromatic vinyl mainly composed of 4-tert-butylstyrene units) Block copolymer consisting of a polymer block (C) (synthesis of sulfonated tBSSEPStBS)
40 g of the block copolymer (tBSSEPStBS) obtained in Reference Example 3 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, and then added with 452 ml of methylene chloride and stirred at room temperature. And dissolved. After dissolution, a sulfonation reagent obtained by reacting 55.5 ml of acetic anhydride and 24.8 ml of sulfuric acid at 0 ° C. in 111 ml of methylene chloride was gradually added dropwise over 5 minutes. After stirring at room temperature for 72 hours, 20 ml of distilled water as a stopper was added. Thereafter, 0.7 L of distilled water was slowly poured into the polymer solution to coagulate and precipitate the polymer. The methylene chloride was removed by distillation at atmospheric pressure, followed by filtration. The solid content obtained by filtration was transferred to a beaker, 1.3 L of distilled water was added, and washing was performed with stirring, followed by filtration and recovery. This washing and filtration operation was repeated until there was no change in the pH of the washing water. Finally, the polymer collected by filtration was vacuum dried to obtain a sulfonated tBSSEPStBS, which is a polymer electrolyte not belonging to the present invention. The content of sulfonic acid group per repeating unit of the polymer block containing styrene group modified with sulfonic acid group of the obtained sulfonated tBSSEPStBS is 1.00 from 1 H-NMR analysis, and the ion exchange of the polymer electrolyte The capacity was 2.30 meq / g.
＜製造例６＞
（主としてスルホン化４－ビニルビフェニル単位からなる芳香族ビニル系重合体ブロック（Ａ）、主として水添イソプレン単位からなる脂肪族ビニル系重合体ブロック（Ｂ）及び主として４－ｔｅｒｔ－ブチルスチレン単位からなる芳香族ビニル系重合体ブロック（Ｃ）からなるブロック共重合体（スルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳ）の合成）
　参考例１で得られたブロック共重合体（ｔＢＳＶＢｔＢＳＥＰｔＢＳ）５ｇを、撹拌機付きのガラス製反応容器中にて１時間真空乾燥し、ついで窒素置換した後、塩化メチレン２００ｍｌを加え、室温にて攪拌して溶解させた。溶解後、塩化メチレン５０ｍｌ、クロロスルホン酸２．８ｍｌの混合溶液を、３０分かけて徐々に滴下した。室温にて７時間攪拌後、停止剤としての蒸留水を１０ｍｌ添加した。その後、攪拌下、２５０ｍｌの蒸留水を重合体溶液にゆっくり注ぎ、重合体を凝固析出させた。塩化メチレンを常圧留去にて除去した後、ろ過した。ろ過により得られた固形分をビーカーに移し、蒸留水を１Ｌ添加して、攪拌下で洗浄を行った後、ろ過回収を行った。この洗浄及びろ過の操作を洗浄水のｐＨに変化がなくなるまで繰り返し、最後にろ集した重合体を真空乾燥して本発明に属しない高分子電解質であるスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳを得た。得られたスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳのスルホン酸基変性した４－ビニルビフェニル単位のベンゼン環を含む重合体ブロックの繰り返し単位あたりのスルホン酸基含有量は滴定から１.３０個であり、該高分子電解質のイオン交換容量は２．１７ｍｅｑ／ｇであった。 <Production Example 6>
(Aromatic vinyl polymer block (A) mainly composed of sulfonated 4-vinylbiphenyl units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and mainly composed of 4-tert-butylstyrene units) Block copolymer composed of aromatic vinyl polymer block (C) (synthesis of sulfonated tBSVBtBSEPtBS)
5 g of the block copolymer (tBSVBtBSEPtBS) obtained in Reference Example 1 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, followed by addition of 200 ml of methylene chloride and stirring at room temperature. And dissolved. After dissolution, a mixed solution of 50 ml of methylene chloride and 2.8 ml of chlorosulfonic acid was gradually added dropwise over 30 minutes. After stirring for 7 hours at room temperature, 10 ml of distilled water as a stopper was added. Thereafter, 250 ml of distilled water was slowly poured into the polymer solution with stirring to solidify and precipitate the polymer. The methylene chloride was removed by distillation at atmospheric pressure, followed by filtration. The solid content obtained by filtration was transferred to a beaker, 1 L of distilled water was added, washed with stirring, and then collected by filtration. This washing and filtration operation was repeated until there was no change in the pH of the washing water. Finally, the polymer collected by filtration was vacuum dried to obtain a sulfonated tBSVBtBSEPtBS which is a polymer electrolyte not belonging to the present invention. The content of sulfonic acid groups per repeating unit of the polymer block containing a benzene ring of 4-vinylbiphenyl units modified with sulfonic acid groups of the obtained sulfonated tBSVBtBSEPtBS is 1.30 from titration. The ion exchange capacity was 2.17 meq / g.
＜製造例７＞
（主としてスルホン化スチレン単位からなる芳香族ビニル系重合体ブロック（Ａ）、主として水添イソプレン単位からなる脂肪族ビニル系重合体ブロック（Ｂ）及び主として４－ｔｅｒｔ－ブチルスチレン単位からなる芳香族ビニル系重合体ブロック（Ｃ）からなるブロック共重合体（スルホン化ｔＢＳＳＥＰＳｔＢＳ）の合成）
　参考例５で得られたブロック共重合体（ｔＢＳＳＥＰＳｔＢＳ）４０ｇを、攪拌機付きのガラス製反応容器中にて１時間真空乾燥し、ついで窒素置換した後、塩化メチレン５４０ｍｌを加え、室温にて攪拌して溶解させた。溶解後、塩化メチレン４４．５ｍｌ中、０℃にて無水酢酸８９．０ｍｌと硫酸５１．８ｍｌとを反応させて得られたスルホン化試薬を、５分かけて徐々に滴下した。室温にて７２時間攪拌後、停止剤の蒸留水を２０ｍｌ添加した。その後、０．６Ｌの蒸留水を重合体溶液にゆっくり注ぎ、重合体を凝固析出させた。塩化メチレンを常圧留去にて除去した後、ろ過した。ろ過により得られた固形分をビーカーに移し、蒸留水を１．３Ｌ添加して、攪拌下で洗浄を行った後、ろ過回収を行った。この洗浄及びろ過の操作を洗浄水のｐＨに変化がなくなるまで繰り返し、最後にろ集した重合体を真空乾燥して本発明に属しない高分子電解質であるスルホン化ｔＢＳＳＥＰＳｔＢＳを得た。得られたスルホン化ｔＢＳＳＥＰＳｔＢＳのスルホン酸基変性したスチレン単位を含む重合体ブロックの繰り返し単位あたりのスルホン酸基含有量は1Ｈ－ＮＭＲ分析から１．００個であり、該高分子電解質のイオン交換容量は２．９９ｍｅｑ／ｇであった。 <Production Example 7>
(Aromatic vinyl polymer block (A) mainly composed of sulfonated styrene units, aliphatic vinyl polymer block (B) mainly composed of hydrogenated isoprene units, and aromatic vinyl mainly composed of 4-tert-butylstyrene units) Block copolymer consisting of a polymer block (C) (synthesis of sulfonated tBSSEPStBS)
40 g of the block copolymer (tBSSEPStBS) obtained in Reference Example 5 was vacuum-dried in a glass reaction vessel equipped with a stirrer for 1 hour and then purged with nitrogen, and then added with 540 ml of methylene chloride and stirred at room temperature. And dissolved. After dissolution, a sulfonation reagent obtained by reacting 89.0 ml of acetic anhydride and 51.8 ml of sulfuric acid at 0 ° C. in 44.5 ml of methylene chloride was gradually added dropwise over 5 minutes. After stirring at room temperature for 72 hours, 20 ml of distilled water as a stopper was added. Thereafter, 0.6 L of distilled water was slowly poured into the polymer solution to solidify and precipitate the polymer. The methylene chloride was removed by distillation at atmospheric pressure, followed by filtration. The solid content obtained by filtration was transferred to a beaker, 1.3 L of distilled water was added, and washing was performed with stirring, followed by filtration and recovery. This washing and filtration operation was repeated until there was no change in the pH of the washing water. Finally, the polymer collected by filtration was vacuum dried to obtain a sulfonated tBSSEPStBS, which is a polymer electrolyte not belonging to the present invention. The content of sulfonic acid group per repeating unit of the polymer block containing styrene group modified with sulfonic acid group of the obtained sulfonated tBSSEPStBS is 1.00 from 1 H-NMR analysis, and the ion exchange of the polymer electrolyte The capacity was 2.99 meq / g.
＜実施例１＞
（高分子電解質膜の作製）
　製造例１で得られたスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳ（イオン交換容量３．０ｍｅｑ／ｇ）の２５重量％のトルエン／イソブチルアルコール（重量比６／４）溶液を調製し、離型処理済みＰＥＴフィルム［（株）東洋紡製「東洋紡エステルフィルムＫ１５０４」］上に約２５０μｍの厚みでコートし、熱風乾燥機にて、１００℃、４分間乾燥させることで、厚さ３５μｍの膜を得た。 <Example 1>
(Production of polymer electrolyte membrane)
A 25 wt% toluene / isobutyl alcohol (weight ratio 6/4) solution of the sulfonated tBSVBtBSEPtBS (ion exchange capacity 3.0 meq / g) obtained in Production Example 1 was prepared, and a release-treated PET film [(stock ) “Toyobo Ester Film K1504” manufactured by Toyobo Co., Ltd.] was coated at a thickness of about 250 μm and dried in a hot air dryer at 100 ° C. for 4 minutes to obtain a film having a thickness of 35 μm.
＜実施例２＞
（高分子電解質膜の作製）
　製造例２で得られたスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳ（イオン交換容量２．７７ｍｅｑ／ｇ）の３０重量％のトルエン／イソブチルアルコール（重量比６／４）溶液を調製し、離型処理済みＰＥＴフィルム［（株）東洋紡製「東洋紡エステルフィルムＫ１５０４」］上に約１５０μｍの厚みでコートし、熱風乾燥機にて、１００℃、４分間乾燥させることで、厚さ２０μｍの膜を得た。 <Example 2>
(Production of polymer electrolyte membrane)
A 30% by weight toluene / isobutyl alcohol (weight ratio 6/4) solution of the sulfonated tBSVBtBSEPtBS (ion exchange capacity 2.77 meq / g) obtained in Production Example 2 was prepared, and a release-treated PET film [(Strain ) "Toyobo Ester Film K1504" manufactured by Toyobo Co., Ltd.] with a thickness of about 150 μm, and dried in a hot air dryer at 100 ° C. for 4 minutes to obtain a 20 μm thick film.
＜実施例３＞
（高分子電解質膜の作製）
　製造例３で得られたスルホン化ｔＢＳＶＢＥＰＶＢｔＢＳ（イオン交換容量２．３３ｍｅｑ／ｇ）の１重量％のクロロベンゼン溶液を調製し、ポリテトラフルオロエチレンシートで作製した容器にキャストした後、１～数日かけて溶媒を徐々に除去することによって、厚さ２９μｍの膜を得た。 <Example 3>
(Production of polymer electrolyte membrane)
A 1% by weight chlorobenzene solution of the sulfonated tBSVBEPVBtBS (ion exchange capacity 2.33 meq / g) obtained in Production Example 3 was prepared and cast into a container made of a polytetrafluoroethylene sheet. By gradually removing the solvent, a 29 μm thick film was obtained.
＜比較例１＞
（高分子電解質膜の作製）
　製造例４で得られたスルホン化ｔＢＳＳＥＰＳｔＢＳの１８重量％のトルエン／イソプロピルアルコール（重量比５／５）溶液を調製し、離型処理済みＰＥＴフィルム［（株）東洋紡製「東洋紡エステルフィルムＫ１５０４」］上に約３５０μｍの厚みでコートし、１００℃で４分乾燥後、ＰＥＴフィルムから剥離することで、厚さ３０μｍの膜を得た。 <Comparative Example 1>
(Production of polymer electrolyte membrane)
A 18% by weight toluene / isopropyl alcohol (5/5 by weight) solution of the sulfonated tBSSEPStBS obtained in Production Example 4 was prepared, and a release-treated PET film [“Toyobo Ester Film K1504” manufactured by Toyobo Co., Ltd.] A film having a thickness of about 350 μm was coated thereon, dried at 100 ° C. for 4 minutes, and then peeled off from the PET film to obtain a film having a thickness of 30 μm.
＜比較例２＞
（高分子電解質膜の作製）
　製造例５で得られたスルホン化ｔＢＳＳＥＰＳｔＢＳの１９重量％のトルエン／イソプロピルアルコール（重量比５／５）溶液を調製し、離型処理済みＰＥＴフィルム［（株）東洋紡製「東洋紡エステルフィルムＫ１５０４」］上に約３５０μｍの厚みでコートし、１００℃で４分乾燥後、ＰＥＴフィルムから剥離することで、厚さ３１μｍの膜を得た。 <Comparative Example 2>
(Production of polymer electrolyte membrane)
A 19% by weight toluene / isopropyl alcohol (weight ratio 5/5) solution of the sulfonated tBSSEPStBS obtained in Production Example 5 was prepared, and a release-treated PET film ["Toyobo Ester Film K1504" manufactured by Toyobo Co., Ltd.] A film with a thickness of about 350 μm was coated thereon, dried at 100 ° C. for 4 minutes, and then peeled off from the PET film to obtain a film with a thickness of 31 μm.
＜比較例３＞
（高分子電解質膜の作製）
　製造例６で得られたスルホン化ｔＢＳＶＢｔＢＳＥＰｔＢＳ（イオン交換容量２．１７ｍｅｑ／ｇ）の３０重量％のトルエン／イソブチルアルコール（重量比６／４）溶液を調製し、離型処理済みＰＥＴフィルム［（株）東洋紡製「東洋紡エステルフィルムＫ１５０４」］上に約２５０μｍの厚みでコートし、熱風乾燥機にて、１００℃、４分間乾燥させることで、厚さ３３μｍの膜を得た。 <Comparative Example 3>
(Production of polymer electrolyte membrane)
A 30% by weight toluene / isobutyl alcohol (weight ratio 6/4) solution of the sulfonated tBSVBtBSEPtBS (ion exchange capacity 2.17 meq / g) obtained in Production Example 6 was prepared, and a release-treated PET film [(Strain ) “Toyobo Ester Film K1504” manufactured by Toyobo Co., Ltd.] was coated to a thickness of about 250 μm, and dried in a hot air dryer at 100 ° C. for 4 minutes to obtain a film having a thickness of 33 μm.
　＜比較例４＞
（高分子電解質膜の作製）
　製造例７で得られたスルホン化ｔＢＳＳＥＰＳｔＢＳ（イオン交換容量２．９９ｍｅｑ／ｇ）の１８重量％のトルエン／イソプロピルアルコール（重量比５／５）溶液を調製し、離型処理済みＰＥＴフィルム［（株）東洋紡製「東洋紡エステルフィルムＫ１５０４」］上に約３５０μｍの厚みでコートし、１００℃で４分乾燥後、ＰＥＴフィルムから剥離することで、厚さ３０μｍの膜を得た。 <Comparative Example 4>
(Production of polymer electrolyte membrane)
A 18% by weight toluene / isopropyl alcohol (5/5 weight ratio) solution of the sulfonated tBSSEPStBS (ion exchange capacity 2.99 meq / g) obtained in Production Example 7 was prepared, and the release-treated PET film [(stock ) “Toyobo Ester Film K1504” manufactured by Toyobo Co., Ltd.] was coated at a thickness of about 350 μm, dried at 100 ° C. for 4 minutes, and then peeled off from the PET film to obtain a film having a thickness of 30 μm.
（実施例及び比較例の高分子電解質膜の性能試験及びその結果）
　各実施例又は比較例で得られた、スルホン化ブロック共重合体からなる高分子電解質膜の性能試験を以下のように行った。 (Performance tests and results of polymer electrolyte membranes of Examples and Comparative Examples)
The performance test of the polymer electrolyte membrane made of the sulfonated block copolymer obtained in each Example or Comparative Example was performed as follows.
（イオン伝導度の測定）
　１ｃｍ×４ｃｍの高分子電解質膜を１対の白金電極で挟み、開放系セルに装着した。測定セルを、温度８０℃及び相対湿度３０％に調節した恒温恒湿器内に設置し、交流インピーダンス法により上記膜のイオン伝導度を測定した。 (Ion conductivity measurement)
A polymer electrolyte membrane of 1 cm × 4 cm was sandwiched between a pair of platinum electrodes and attached to an open cell. The measurement cell was installed in a constant temperature and humidity chamber adjusted to a temperature of 80 ° C. and a relative humidity of 30%, and the ionic conductivity of the membrane was measured by an AC impedance method.
　（線膨張率の測定）
　１ｃｍ×４ｃｍの試料を室温で４時間蒸留水に浸漬した後に、長手方向の長さ（ｘ）を計測し、以下の式により算出した。
　線膨張率（％）＝（ｘ－４）／４×１００ (Measurement of linear expansion coefficient)
After immersing a sample of 1 cm × 4 cm in distilled water at room temperature for 4 hours, the length (x) in the longitudinal direction was measured and calculated by the following formula.
Linear expansion coefficient (%) = (x−4) / 4 × 100
　実施例１～３と比較例１～４で用いた高分子電解質、及び、作製した高分子電解質膜に関するイオン伝導度及び線膨張率の測定結果を表１に示す。 Table 1 shows the measurement results of ionic conductivity and linear expansion coefficient of the polymer electrolytes used in Examples 1 to 3 and Comparative Examples 1 to 4 and the produced polymer electrolyte membranes.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例１と比較例４を比較すると、ほぼ同じイオン交換容量であっても実施例１の方がイオン伝導度が高く、線膨張率が低いことが分かる。すなわち、本発明の高分子電解質膜はイオン伝導性が高く、水中での形状安定性も高い。実施例３と比較例２の比較でも同様のことが言える。
　また、同程度のイオン伝導度を示す実施例２と比較例４を比較すると、実施例２の方がはるかに線膨張率が低く、水中での形状安定性に優れる。 When Example 1 and Comparative Example 4 are compared, it can be seen that Example 1 has a higher ion conductivity and a lower linear expansion coefficient even if the ion exchange capacity is substantially the same. That is, the polymer electrolyte membrane of the present invention has high ion conductivity and high shape stability in water. The same can be said for the comparison between Example 3 and Comparative Example 2.
Moreover, when Example 2 and Comparative Example 4 which show comparable ionic conductivity are compared, Example 2 has a much lower linear expansion coefficient and is excellent in shape stability in water.
　上記試験の結果から、本発明の高分子電解質からなる高分子電解質膜は、低湿度下におけるイオン伝導性に優れるため、これを用いた膜－電極接合体及び固体高分子型燃料電池の低湿度下における出力特性も優れると言える。また、該高分子電解質膜は水による膨潤が少なく、水中での形状安定性が良好である。 From the results of the above test, the polymer electrolyte membrane comprising the polymer electrolyte of the present invention is excellent in ionic conductivity under low humidity. Therefore, the low humidity of the membrane-electrode assembly and the solid polymer fuel cell using the same The output characteristics below are also excellent. Further, the polymer electrolyte membrane is less swollen by water and has good shape stability in water.
　本発明の高分子電解質、これからなる高分子電解質膜を用いることにより、低湿度下における出力特性に優れた膜－電極接合体、及び固体高分子型燃料電池を提供できる。 By using the polymer electrolyte of the present invention and a polymer electrolyte membrane comprising the polymer electrolyte, a membrane-electrode assembly excellent in output characteristics under low humidity and a solid polymer fuel cell can be provided.

Claims (10)

  1. 　少なくとも芳香族ビニル系重合体ブロック（Ａ）と脂肪族ビニル系重合体ブロック（Ｂ）とを構成成分とするブロック共重合体からなる高分子電解質であって、前記芳香族ビニル系重合体ブロック（Ａ）における繰り返し単位あたりのイオン伝導性基含有量が１．５～３．０個であって、前記脂肪族ビニル系重合体ブロック（Ｂ）がイオン伝導性基を有しないことを特徴とする高分子電解質。 A polymer electrolyte comprising a block copolymer having at least an aromatic vinyl polymer block (A) and an aliphatic vinyl polymer block (B) as constituent components, wherein the aromatic vinyl polymer block ( The ion conductive group content per repeating unit in A) is 1.5 to 3.0, and the aliphatic vinyl polymer block (B) does not have an ion conductive group. Polymer electrolyte.
  2. 　前記芳香族ビニル系重合体ブロック（Ａ）が前記高分子電解質の５～５０重量％を占めることを特徴とする請求項１に記載の高分子電解質。 2. The polymer electrolyte according to claim 1, wherein the aromatic vinyl polymer block (A) accounts for 5 to 50% by weight of the polymer electrolyte.
  3. 　前記芳香族ビニル系重合体ブロック（Ａ）１ｇあたりのイオン伝導性基含有量が４．８ｍｅｑ／ｇ以上であることを特徴とする請求項１に記載の高分子電解質。 2. The polymer electrolyte according to claim 1, wherein an ion conductive group content per 1 g of the aromatic vinyl polymer block (A) is 4.8 meq / g or more.
  4. 　前記脂肪族ビニル系重合体ブロック（Ｂ）が、炭素数２～８のアルケン単位、炭素数５～８のシクロアルケン単位、炭素数７～１０のビニルシクロアルカン単位、炭素数７～１０のビニルシクロアルケン単位、炭素数４～８の共役ジエン単位及び炭素数５～８の共役シクロアルカジエン単位からなる群より選ばれる少なくとも１種の繰り返し単位を主成分とするゴム状重合体ブロックであることを特徴とする請求項１に記載の高分子電解質。 The aliphatic vinyl polymer block (B) is an alkene unit having 2 to 8 carbon atoms, a cycloalkene unit having 5 to 8 carbon atoms, a vinyl cycloalkane unit having 7 to 10 carbon atoms, or a vinyl having 7 to 10 carbon atoms. It is a rubbery polymer block containing as a main component at least one repeating unit selected from the group consisting of a cycloalkene unit, a conjugated diene unit having 4 to 8 carbon atoms, and a conjugated cycloalkadiene unit having 5 to 8 carbon atoms. The polymer electrolyte according to claim 1, wherein
  5. 　前記イオン伝導性基がプロトン伝導性基であることを特徴とする請求項１に記載の高分子電解質。 The polymer electrolyte according to claim 1, wherein the ion conductive group is a proton conductive group.
  6. 　主としてイオン伝導性基を有しない芳香族ビニル系化合物単位を繰り返し単位とする芳香族ビニル系重合体ブロック（Ｃ）を構成成分として２０～６０重量％含むことを特徴とする請求項１に記載の高分子電解質。 The aromatic vinyl polymer block (C) mainly comprising an aromatic vinyl compound unit having no ion conductive group as a repeating unit is contained as a constituent component in an amount of 20 to 60% by weight. Polymer electrolyte.
  7. 　前記芳香族ビニル系重合体ブロック（Ｃ）の主たる繰り返し単位である前記芳香族ビニル系化合物単位は１～３個の炭素数１～８の炭化水素基を芳香環上に有する置換芳香族ビニル系化合物単位であることを特徴とする請求項６に記載の高分子電解質。 The aromatic vinyl compound unit, which is the main repeating unit of the aromatic vinyl polymer block (C), is a substituted aromatic vinyl compound having 1 to 3 C 1-8 hydrocarbon groups on the aromatic ring. The polymer electrolyte according to claim 6, wherein the polymer electrolyte is a compound unit.
  8. 　請求項１に記載の高分子電解質からなる高分子電解質膜。 A polymer electrolyte membrane comprising the polymer electrolyte according to claim 1.
  9. 　請求項８に記載の高分子電解質膜と電極層との複層構造である膜－電極接合体。 A membrane-electrode assembly having a multilayer structure of the polymer electrolyte membrane according to claim 8 and an electrode layer.
  10. 　請求項９に記載の膜－電極接合体を備える固体高分子型燃料電池。 A polymer electrolyte fuel cell comprising the membrane-electrode assembly according to claim 9.
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