Electrolyte materials, membrane electrode assemblies, and polymer electrolyte fuel cells

Abstract

The present invention provides: an electrolyte material which enables the formation of a fuel cell having excellent power generation characteristics by suppressing cracking of a catalyst layer if applied to the catalyst layer in a membrane electrode assembly; a membrane electrode assembly; and a polymer electrolyte fuel cell.　An electrolyte material according to the present invention is formed of a polymer that has an ion exchange group; and the polymer comprises a unit based on tetrafluoroethylene, a unit having an ion exchange group without containing a cyclic ether structure, a unit containing a cyclic ether structure, and a unit based on a monomer that has two or more polymerizable unsaturated bonds.

Description

[Technical Field]

[0001] The present invention relates to an electrolyte material, a membrane electrode assembly, and a polymer electrolyte fuel cell. [Background technology]

[0002] It is known that a membrane electrode assembly of a polymer electrolyte fuel cell includes an anode having a catalyst layer containing an electrolyte material, a cathode having a catalyst layer containing an electrolyte material, and a solid polymer electrolyte membrane disposed between the anode and the cathode and containing an electrolyte material. The electrolyte material used for each member constituting the membrane electrode assembly is composed of a polymer having an ion exchange group. Patent Document 1 discloses that an electrolyte material made of a polymer having a unit based on tetrafluoroethylene, a unit having an ion exchange group, and a unit containing a cyclic ether structure is used in a catalyst layer of a cathode or anode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 104380 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for further improvements in the performance of fuel cells. The present inventors have found that when an electrolyte material such as that described in Patent Document 1 is used for a catalyst layer, the power generation characteristics of the fuel cell are good, but cracking of the catalyst layer cannot be sufficiently suppressed, and there is room for improvement.

[0005] The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an electrolyte material, a membrane electrode assembly, and a solid polymer fuel cell that, when applied to a catalyst layer of a membrane electrode assembly, can suppress cracking of the catalyst layer and form a fuel cell with excellent power generation characteristics. [Means for solving the problem]

[0006] As a result of intensive research into the above-mentioned problems, the present inventors have found that the desired effects can be obtained by using, in a catalyst layer, an electrolyte material composed of a polymer having a unit based on tetrafluoroethylene, a unit not containing a cyclic ether structure and having an ion exchange group, a unit containing a cyclic ether structure, and a unit based on a monomer having two or more polymerizable unsaturated bonds, and have arrived at the present invention.

[0007] That is, the present inventors have found that the above problems can be solved by the following configuration. [1] An electrolyte material made of a polymer having an ion exchange group, The electrolyte material is characterized in that the polymer has a unit based on tetrafluoroethylene, a unit not containing a cyclic ether structure and having an ion exchange group, a unit containing a cyclic ether structure, and a unit based on a monomer having two or more polymerizable unsaturated bonds. [2] The molar ratio of the content of units based on the monomer having two or more polymerizable unsaturated bonds to the content of units based on tetrafluoroethylene is 4.3 × 10 -4 ~9.9×10 -3 The electrolyte material according to [1], [3] The molar ratio of the content of the unit based on the monomer having two or more polymerizable unsaturated bonds to the content of the unit containing the cyclic ether structure is 6.7 × 10 -4 ~9.9×10 -3 The electrolyte material according to [1] or [2], [4] The electrolyte material according to any one of [1] to [3], wherein the content of units based on the monomer having two or more polymerizable unsaturated bonds relative to all units contained in the polymer having an ion exchange group is 0.001 to 10 mol %. [5] The electrolyte material according to any one of [1] to [4], wherein the unit containing a cyclic ether structure is at least one unit selected from the group consisting of a unit represented by the formula (u11) described below, a unit represented by the formula (u12) described below, a unit represented by the formula (u21) described below, a unit represented by the formula (u22) described below, and a unit represented by the formula (u24) described below. In formula (u11), R 11 is a divalent perfluoroalkylene group which may have an ether-bonded oxygen atom, and R 12 , R 13 , R 15 and R 16 are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom, and R 14 represents a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom, a fluorine atom, or -R 11 (SO2X(SO2R f ) a ) - M + It is a group represented by M + is H + , a monovalent metal cation or an ammonium ion in which one or more hydrogen atoms may be substituted with a hydrocarbon group, and R f represents a linear or branched perfluoroalkyl group which may have an ether-bonded oxygen atom, X represents an oxygen atom, a nitrogen atom, or a carbon atom, and when X represents an oxygen atom, a=0; when X represents a nitrogen atom, a=1; and when X represents a carbon atom, a=2. In formula (u12), R 21 is a perfluoroalkylene group having 1 to 6 carbon atoms or a perfluoroalkylene group having 2 to 6 carbon atoms and an ether-bonding oxygen atom between the carbon-carbon bonds, and R 22 represents a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms, a perfluoroalkyl group having 2 to 6 carbon atoms and an ether-bonded oxygen atom between the carbon-carbon bonds, or -R 21 (SO2X(SO2R f ) a ) - M + It is a group represented by M + , Rf , X and a are the same as above. In formula (u21), R 41 , R 42 , R 43 , R 44 , R 45 and R 46 are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom. In formula (u22), s is 0 or 1, and R 51 and R 52 are each independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a spiro ring formed by linking together (when s is 0), and R 53 and R 54 are each independently a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and R 55 is a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms. In formula (u24), R 71 , R 72 , R 73 , R 74 , R 75 and R 76 are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom. [6] The electrolyte material according to [5], wherein the unit containing a cyclic ether structure is a unit represented by formula (u22). [7] The electrolyte material according to any one of [1] to [6], wherein the unit based on a monomer having two or more polymerizable unsaturated bonds is a unit represented by formula (u41) described below. In formula (u41), Q 4 is an oxygen atom or a divalent perfluoroalkylene group which may have an ether-bonding oxygen atom. [8] The electrolyte material according to [7], wherein the unit based on a monomer having two or more polymerizable unsaturated bonds is at least one unit selected from the group consisting of a unit represented by the formula (u41-1), a unit represented by the formula (u41-2), and a unit represented by the formula (u41-3) described below. [9] The electrolyte material according to any one of [1] to [8], wherein the unit having an ion exchange group and not containing a cyclic ether structure is at least one of a unit represented by the formula (u31) described below and a unit represented by the formula (u32) described below. In formula (u31), Z is a fluorine atom or a trifluoromethyl group, q is 0 or 1, m is an integer of 0 to 3, p is 0 or 1, n is an integer of 1 to 12, m+p>0, and M + is H + , a monovalent metal cation, or an ammonium ion in which one or more hydrogen atoms may be substituted with a hydrocarbon group. In formula (u32), Q 1 is a perfluoroalkylene group which may have an ether-bonded oxygen atom, and Q 2 represents a single bond or a perfluoroalkylene group which may have an ether bond oxygen atom, Y represents a fluorine atom or a monovalent perfluoroalkyl group, q represents 0 or 1, and R f is a linear or branched perfluoroalkyl group which may have an ether-bonded oxygen atom, X is an oxygen atom, a nitrogen atom or a carbon atom, a=0 when X is an oxygen atom, a=1 when X is a nitrogen atom, and a=2 when X is a carbon atom, R f If there are multiple R f They may be the same or different.

[10] The electrolyte material according to any one of [1] to [9], wherein the ion exchange capacity of the polymer is 0.5 to 2.5 meq / g dry resin.

[11] A membrane electrode assembly comprising: an anode having a catalyst layer containing an electrolyte material made of a catalyst and a polymer having ion exchange groups; a cathode having a catalyst layer containing an electrolyte material made of a catalyst and a polymer having ion exchange groups; and a solid polymer electrolyte membrane disposed between the anode and the cathode and containing a fluorine-containing polymer having ion exchange groups, A membrane / electrode assembly, wherein at least one of the electrolyte material contained in the anode and the electrolyte material contained in the cathode is the electrolyte material according to any one of [1] to

[10] .

[12] A polymer electrolyte fuel cell comprising the membrane electrode assembly according to

[11] . [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an electrolyte material, a membrane electrode assembly, and a polymer electrolyte fuel cell which, when applied to a catalyst layer of a membrane electrode assembly, can suppress cracking of the catalyst layer and form a fuel cell with excellent power generation characteristics. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an example of a membrane electrode assembly of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The terms used in the present invention have the following meanings. The term "unit" in a polymer refers to an atomic group derived from one molecule of a monomer formed by polymerization of the monomer. The unit may be an atomic group formed directly by the polymerization reaction, or may be an atomic group in which a part of the atomic group is converted into a different structure by treating the polymer obtained by the polymerization reaction. The term "precursor group of an ion exchange group" refers to a group that can be converted into an ion exchange group by hydrolysis, acidification, or other treatment such as salt exchange with a metal cation. The term "precursor polymer" refers to a polymer in which the ion-exchange groups are in the form of precursor groups and which can be converted into a polymer having ion-exchange groups. The "TQ value" is the volumetric flow rate value of a polymer, and is determined by the method described in the Examples section. The TQ value is an index of molecular weight. A numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0011] The unit represented by formula (u11) is written as unit (u11). Units represented by other formulas are written in the same way. Furthermore, the monomer represented by formula (m11) will be referred to as monomer (m11). Monomers represented by other formulas will be similarly referred to. The units (u11), (u12), (u21), (u22) and (u24) may be collectively referred to as "specific cyclic ether structural units". The monomer (m11), the monomer (m12), the monomer (m21), the monomer (m22) and the monomer (m24) may be collectively referred to as "specific cyclic monomers".

[0012] The content (mol %) of each unit contained in the polymer is calculated from the amount of each monomer charged when producing the polymer.

[0013] [Electrolyte materials] The electrolyte material of the present invention is an electrolyte material made of a polymer having an ion exchange group, and the polymer has a unit based on tetrafluoroethylene (hereinafter also referred to as "unit A"), a unit having an ion exchange group but not containing a cyclic ether structure (hereinafter also referred to as "unit B"), a unit containing a cyclic ether structure (hereinafter also referred to as "unit C"), and a unit based on a monomer having two or more polymerizable unsaturated bonds (hereinafter also referred to as "unit D"). Hereinafter, the above polymer constituting the electrolyte material of the present invention will also be referred to as "polymer (H)". The electrolyte material of the present invention can provide a catalyst layer with reduced cracking and a fuel cell with excellent power generation characteristics. Although the details of the reason for this are not clear, it is presumed that this is due to the polymer (H) having both units C and D.

[0014] The polymer (H) is suitably used as a polymer constituting the electrolyte material contained in the catalyst layer of the membrane electrode assembly.

[0015] <Unit A> The unit A is a unit based on tetrafluoroethylene (TFE). The presence of the unit A imparts water repellency, increases the water discharge ability in the catalyst layer, and improves the power generation efficiency of the fuel cell. The content of the unit A is preferably from 1 to 50 mol %, more preferably from 10 to 45 mol %, particularly preferably from 20 to 35 mol %, based on all units contained in the polymer (H).

[0016] <Unit B> The unit B does not contain a cyclic ether structure and has an ion-exchange group. The unit B is preferably a unit based on a perfluoromonomer having an ion-exchange group and does not contain a cyclic ether structure, more preferably the unit (u31) or the unit (u32) in terms of achieving better power generation efficiency of the fuel cell, and particularly preferably the unit (u32) in terms of achieving better power generation efficiency of the fuel cell.

[0017] [ka]

[0018] In the unit (u31), Z is a fluorine atom or a trifluoromethyl group, q is 0 or 1, m is an integer of 0 to 3, p is 0 or 1, n is an integer of 1 to 12, and m+p>0. M + is H +, a monovalent metal cation (e.g., potassium ion, sodium ion) or an ammonium ion in which one or more hydrogen atoms may be substituted with a hydrocarbon group (e.g., methyl group, ethyl group). From the viewpoint of high conductivity, H + is preferred.

[0019] [ka]

[0020] Unit (u32), Q 1 is a perfluoroalkylene group which may have an ether-bonding oxygen atom. Q 2 is a single bond or a perfluoroalkylene group which may have an ether-bonding oxygen atom. Q 1 and Q 2 When the perfluoroalkylene group has an ether-bonding oxygen atom, the number of oxygen atoms may be 1 or 2 or more. The ether-bonding oxygen atom may be located between the carbon atom-carbon atom bonds of the perfluoroalkylene group, or may be located at the end of the carbon atom bond. The perfluoroalkylene group may be linear or branched, but is preferably linear. The number of carbon atoms in the perfluoroalkylene group is preferably 1 to 6, particularly preferably 1 to 4. When the number of carbon atoms is 6 or less, the boiling point of the raw material fluorine-containing monomer is low, facilitating distillation purification, and further, the decrease in the ion exchange capacity of the polymer (H) is suppressed, resulting in good proton conductivity.

[0021] Q 2 is preferably a perfluoroalkylene group having 1 to 6 carbon atoms which may have an ether-bonding oxygen atom. 2 is a perfluoroalkylene group having 1 to 6 carbon atoms which may have an ether-bonded oxygen atom, 2 is a single bond, the stability of power generation performance is excellent when the fuel cell is operated for a long period of time. Q 1 and Q2 At least one of the groups is preferably a perfluoroalkylene group having 1 to 6 carbon atoms and an ether-bonding oxygen atom. A monomer having a perfluoroalkylene group having 1 to 6 carbon atoms and an ether-bonding oxygen atom can be synthesized without going through a fluorination reaction with fluorine gas, and therefore has a good yield and is easy to produce.

[0022] Y is a fluorine atom or a monovalent perfluoroalkyl group. Y is preferably a fluorine atom or a linear perfluoroalkyl group having 1 to 6 carbon atoms which may have an ether-bonded oxygen atom, and more preferably a higher functional group (-(SO2X(SO2R f ) a ) - H + A fluorine atom is particularly preferred in terms of achieving a desired group density. q is 0 or 1. R f is a linear or branched perfluoroalkyl group which may have an ether-bonded oxygen atom. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 8, and particularly preferably 1 to 6. Two or more R f If there are two or more R f may be the same or different from each other. X is an oxygen atom, a nitrogen atom, or a carbon atom, and when X is an oxygen atom, a=0; when X is a nitrogen atom, a=1; and when X is a carbon atom, a=2.

[0023] As the unit (u32), the units (u32-1) to (u32-3) are preferred, with the unit (u32-1) being particularly preferred, in view of ease of production and ease of industrial implementation.

[0024] [ka]

[0025] The content of the units B is preferably 30 to 85 mol %, more preferably 40 to 75 mol %, and particularly preferably 45 to 70 mol %, based on the total units contained in the polymer (H). When the content of the units B is equal to or greater than the lower limit of the above range, sufficient ion exchange capacity can be ensured, which is advantageous in that sufficient ion conductivity can be ensured, and when it is equal to or less than the upper limit, swelling of the polymer is suppressed, the flooding phenomenon in the catalyst layer is suppressed, and the membrane electrode assembly can exhibit excellent power generation characteristics even under low temperature and high humidity conditions. The polymer (H) may contain only one type or two or more types of units B. When two or more types are contained, the above content means the total amount thereof.

[0026] <Unit C> The unit C is a unit containing a cyclic ether structure. The unit C is preferably the following specific cyclic ether structural unit, since it allows a catalyst layer with better oxygen permeability to be obtained.

[0027] [ka]

[0028] Unit (u11), R 11 is a divalent perfluoroalkylene group which may have an ether-bonded oxygen atom. When the perfluoroalkylene group has an ether-bonded oxygen atom, the number of oxygen atoms may be one or more. The ether-bonded oxygen atom may be located between the carbon-carbon bonds of the perfluoroalkylene group, or at the carbon atom bond terminal. The perfluoroalkylene group may be linear or branched, but is preferably linear. R 12 , R 13 , R 15 and R 16 R are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom. 15 and R 16In view of high polymerization reactivity, it is preferable that at least one of the groups is a fluorine atom, and it is more preferable that both of the groups are fluorine atoms. R 14 represents a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom, a fluorine atom, or -R 11 (SO2X(SO2R f ) a ) - M + It is a group represented by the formula (u11). When the perfluoroalkyl group has an ether-bonded oxygen atom, the number of oxygen atoms may be one or more. The ether-bonded oxygen atom may be located between the carbon-carbon bonds of the perfluoroalkyl group, or at the end of the carbon atom bond. The perfluoroalkyl group may be linear or branched, but is preferably linear. In formula (u11), two R 11 If it contains two R 11 may be the same or different from each other. M + is H + , a monovalent metal cation (e.g., potassium ion, sodium ion) or an ammonium ion in which one or more hydrogen atoms may be substituted with a hydrocarbon group (e.g., methyl group, ethyl group). From the viewpoint of high conductivity, H + In formula (u11), two M + If it contains two M + may be the same or different from each other. R f is a linear or branched perfluoroalkyl group which may have an ether-bonded oxygen atom. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 8, and particularly preferably 1 to 6. In formula (u11), two or more R f If there are two or more R f may be the same or different from each other. X is an oxygen atom, a nitrogen atom, or a carbon atom, and when X is an oxygen atom, a = 0, when X is a nitrogen atom, a = 1, and when X is a carbon atom, a = 2. When formula (u11) contains two Xs, the two Xs may be the same or different. -(SO2X(SO2R f ) a ) - M + Specific examples of the group include a sulfonic acid group (-SO3 - M + group), sulfonimide group (-SO2N(SO2R f ) - M + group), or sulfonmethide group (-SO2C(SO2R f )2) - M + groups).

[0029] The unit (u11) is preferably the unit (u11-1). + is M in equation (u11) + is synonymous with.

[0030] [ka]

[0031] [ka]

[0032] Unit (u12), R 21 is a perfluoroalkylene group having 1 to 6 carbon atoms or a perfluoroalkylene group having 2 to 6 carbon atoms and having an ether-bonding oxygen atom between the carbon-carbon bond. When the perfluoroalkylene group has an ether-bonding oxygen atom, the number of oxygen atoms may be 1 or 2 or more. The perfluoroalkylene group may be linear or branched, but is preferably linear. R 22 represents a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms, a perfluoroalkyl group having 2 to 6 carbon atoms and an ether-bonded oxygen atom between the carbon-carbon bonds, or -R 21 (SO2X(SO2R f ) a ) - M +When the perfluoroalkyl group has an ether-bonded oxygen atom, the number of oxygen atoms may be one or more. The perfluoroalkyl group may be linear or branched, but is preferably linear. In formula (u12), two R 21 If it contains two R 21 may be the same or different from each other. M + , R f , X and a are the M + , R f , X and a.

[0033] Specific examples of the unit (u12) include the unit (u12-1) and the unit (u12-2). + is M in equation (u11) + is synonymous with.

[0034] [ka]

[0035] [ka]

[0036] Unit (u21), R 41 , R 42 , R 43 , R 44 , R 45 and R 46 are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom. When the perfluoroalkyl group has an ether-bonded oxygen atom, the number of oxygen atoms may be one or two or more. The ether-bonded oxygen atom may be located between the carbon-carbon bonds of the perfluoroalkyl group or at the carbon atom bond terminal. The perfluoroalkyl group may be linear or branched, but is preferably linear. R 45 and R46 In view of high polymerization reactivity, it is preferable that at least one of the groups is a fluorine atom, and it is particularly preferable that both of the groups are fluorine atoms.

[0037] The unit (u21) is preferably the unit (u21-1).

[0038] [ka]

[0039] [ka]

[0040] In the unit (u22), s is 0 or 1, and 0 is preferred. R 51 and R 52 are each independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a spiro ring formed by linking together (when s is 0). R 53 and R 54 are each independently a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms. R 55 R is a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms. 55 is preferably a fluorine atom because of its high polymerization reactivity. The perfluoroalkyl group and perfluoroalkoxy group may be linear or branched, but are preferably linear.

[0041] The unit (u22) is preferably the unit (u22-1).

[0042] [ka]

[0043] [ka]

[0044] Unit (u24), R 71 ~R 76 are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom. When the perfluoroalkyl group has an ether-bonded oxygen atom, the number of oxygen atoms may be one or two or more. The ether-bonded oxygen atom may be inserted between the carbon-carbon bonds of the perfluoroalkyl group or at the carbon atom bond terminal. The perfluoroalkyl group may be linear or branched, but is preferably linear. R 71 ~R 74 is preferably a fluorine atom because of its high polymerization reactivity.

[0045] Among the specific cyclic ether structural units described above, the unit C preferably contains at least one unit selected from the group consisting of the unit (u21), the unit (u22), and the unit (u24), and particularly preferably the unit (u22), in order to obtain a catalyst layer with superior oxygen permeability.

[0046] The lower limit of the content of the units C relative to all units contained in the polymer (H) is preferably 1 mol %, more preferably 5 mol %, particularly preferably 10 mol %, in view of better power generation characteristics of the fuel cell. The upper limit of the content of units C relative to all units contained in polymer (H) is preferably 50 mol%, more preferably 40 mol%, and particularly preferably 30 mol%, from the viewpoints of being able to further suppress the occurrence of cracks in the catalyst layer and of achieving better power generation properties. The polymer (H) may contain only one type of unit C, or may contain two or more types of units C. When two or more types are contained, the above content means the total amount thereof.

[0047] <Unit D> The unit D is a unit based on a monomer having two or more polymerizable unsaturated bonds. In the present invention, a unit based on a monomer containing a cyclic ether structure and having two or more polymerizable unsaturated bonds is treated as the unit D. Specific examples of the polymerizable unsaturated bond include a carbon atom-carbon atom double bond (C=C) and a carbon atom-carbon atom triple bond (C≡C). The number of polymerizable unsaturated bonds in a monomer having two or more polymerizable unsaturated bonds is preferably 2 to 6, more preferably 2 or 3, and particularly preferably 2, in terms of better polymerization reactivity. The monomer having two or more polymerizable unsaturated bonds is preferably a monomer having a fluorine atom, more preferably a perfluoromonomer.

[0048] The unit D is preferably a unit represented by formula (u41) from the viewpoint of further suppressing cracking of the catalyst layer. The unit represented by formula (u41) may be in a form that crosslinks two polymer chains, or may be in a form that is incorporated into the same polymer chain.

[0049] [ka]

[0050] In formula (u41), Q 4 is an oxygen atom or a divalent perfluoroalkylene group which may have an ether-bonding oxygen atom. Q 4 When the perfluoroalkylene group has an ether-bonding oxygen atom, the number of oxygen atoms may be 1 or 2 or more. The ether-bonding oxygen atom may be located between the carbon atom-carbon atom bonds of the perfluoroalkylene group, or may be located at the end of the carbon atom bond. The perfluoroalkylene group may be linear or branched, but is preferably linear. The perfluoroalkylene group preferably has 1 to 10 carbon atoms, more preferably 2 to 8 carbon atoms, and particularly preferably 3 or 4 carbon atoms.

[0051] Specific examples of the unit D include the unit (u41-1), the unit (u41-2) and the unit (u41-3), and the unit (u41-2) is preferred since it can further suppress the occurrence of cracks in the catalyst layer.

[0052] [ka]

[0053] In the above units, m1 and m3 are integers of 2 to 8, with 3 or 4 being particularly preferred. In the above unit, m2 and m4 each independently represent an integer of 0 to 5, and m2+m4≧1.

[0054] The lower limit of the content of the unit D relative to all units contained in the polymer (H) is preferably 0.001 mol %, more preferably 0.005 mol %, and particularly preferably 0.01 mol %, from the viewpoint of further suppressing the occurrence of cracks in the catalyst layer. The upper limit of the content of units D relative to all units contained in polymer (H) is preferably 10 mol %, more preferably 5 mol %, even more preferably 1 mol %, and particularly preferably 0.2 mol %, in terms of better power generation properties. The polymer (H) may contain only one type of unit D, or may contain two or more types of units D. When two or more types are contained, the above content means the total amount thereof.

[0055] <Other units> The polymer (H) may contain units other than those described above (hereinafter also referred to as "other units"). Specific examples of such units include units based on monomers such as perfluoro(3-butenyl vinyl ether), perfluoro(allyl vinyl ether), perfluoroα-olefins (such as hexafluoropropylene), and perfluoro(alkyl vinyl ethers).

[0056] <Content ratio> In polymer (H), the molar ratio of the content of unit D to the content of unit A (content of unit D / content of unit A) is 4.3 × 10 -4 ~9.9×10 -3 is preferred, 7.2 × 10 -4 ~7.5×10 -3 is more preferable, and 1.0×10 -3 ~5.0×10 -3 is particularly preferred, and 1.5 × 10 -3 ~3.3×10 -3 is even more preferable, and 1.5×10 -3 ~3.2×10 -3 is even more preferred. The molar ratio (content of unit D / content of unit A) is 4.3 x 10 -4 If the molar ratio (content of unit D / content of unit A) is 9.9×10 or more, the effect of increasing the molecular weight of polymer (H) is sufficient. -3 If it is below this, the production of the polymer (H) becomes easy. In particular, the molar ratio (content of unit D / content of unit A) is 1.5 × 10 -3 ~3.2×10 -3 Within this range, the occurrence of cracks in the catalyst layer can be further suppressed, and the power generation characteristics of the fuel cell can be further improved.

[0057] In polymer (H), the molar ratio of the content of unit D to the content of unit C (content of unit D / content of unit C) is 6.7 × 10 -4 ~9.9×10 -3 is preferred, 8.4 × 10 -4 ~7.7×10 -3 is more preferable, and 1.0×10 -3 ~5.5×10 -3 is particularly preferred, and 1.4 × 10 -3 ~2.5×10 -3 is even more preferred. The molar ratio (content of unit D / content of unit C) is 6.7 x 10 -4 If the molar ratio (content of unit D / content of unit C) is 9.9×10 or more, the effect of increasing the molecular weight of polymer (H) is sufficient. -3If it is below this, the production of the polymer (H) becomes easy. In particular, the molar ratio (content of unit D / content of unit C) is 1.4 × 10 -3 ~2.5×10 -3 Within this range, the occurrence of cracks in the catalyst layer can be further suppressed, and the power generation characteristics of the fuel cell can be further improved.

[0058] <Physical properties> The ion exchange capacity of the polymer (H) is preferably 0.5 meq / g dry resin or more, more preferably 0.9 meq / g dry resin or more, particularly preferably 1.1 meq / g dry resin or more, and even more preferably 1.3 meq / g dry resin. The ion exchange capacity of the polymer (H) is preferably 2.5 meq / g dry resin or less, more preferably 2.0 meq / g dry resin or less, particularly preferably 1.6 meq / g dry resin or less, and even more preferably 1.5 meq / g dry resin or less. If the ion exchange capacity is above the lower limit, the conductivity of the polymer (H) is high, and sufficient cell output can be obtained when used as a polymer in the catalyst layer of a fuel cell. If the ion exchange capacity is below the upper limit, the polymer can be easily synthesized.

[0059] A particularly preferred embodiment of the polymer (H) is one in which the unit C contains a unit represented by the formula (u22) and the ion exchange capacity is 1.3 meq / g dry resin or more. When the polymer (H) of this embodiment is used as a polymer in a catalyst layer of a fuel cell, the power generation characteristics of the fuel cell are particularly excellent.

[0060] The Q value of the polymer (H) is 1 to 500 mm 3 / sec is preferable, 10 to 300 mm 3 / sec is more preferable, 20-100mm 3 / sec is particularly preferred. Q value is 1mm 3 When the Q value is 500 mm / s or more, the solubility or dispersibility of the polymer (H) is improved, and the liquid composition described below can be easily prepared. 3 If the viscosity is less than 1 / second, the polymer (H) has a sufficient molecular weight and is excellent in mechanical strength. As described below, the Q value represents the extrusion amount (flow rate) per unit time at 300°C when the TQ value exceeds 300°C, and for the same composition, the lower the Q value, the higher the molecular weight of the polymer.

[0061] <Method for producing polymer (H)> Polymer (H) is produced, for example, by converting the precursor group of polymer (F) having a precursor group of an ion exchange group obtained by polymerizing TFE, a perfluoromonomer not containing a cyclic ether structure and having a precursor group of an ion exchange group, a cyclic monomer (preferably a specific cyclic monomer), and a monomer having two or more polymerizable unsaturated bonds, into an ion exchange group. The precursor group of the ion exchange group is a group that can be converted into the ion exchange group by a treatment such as hydrolysis described later. For example, when the ion exchange group is a sulfonic acid group (-SO3H), the precursor group is a sulfonyl fluoride group (-SO2F). Each monomer that can be used to produce the polymer (H) will be explained below.

[0062] (Perfluoromonomers that do not contain cyclic ether structures and have precursor groups for ion exchange groups) Examples of perfluoromonomers that do not contain a cyclic ether structure and have a precursor group of an ion-exchange group include monomer (m31) and monomer (m32), and monomer (m32) is preferred in terms of better power generation characteristics of the fuel cell.

[0063] CF2=CF(CF2) q (OCF2CFZ) m O p (CF2) n SO2F (m31)

[0064] The monomer (m31) corresponds to the unit (u31). Z, q, m, p, and n have the same meanings as Z, q, m, p, and n in formula (u31), respectively.

[0065] The monomer (m31) is preferably the monomers (m31-1) to (m31-4). CF2=CFO(CF2) n1 SO2F (m31-1) CF2=CFCF2O(CF2) n4 SO2F (m31-2) CF2=CF(OCF2CF(CF3)) m3 O(CF2) n3 SO2F (m31-3) CF2=CFOCF2CF(CF3)O(CF2) n2 SO2F (m31-4) Here, n1, n2, n3, and n4 are integers from 1 to 12, and m3 is an integer from 1 to 3.

[0066] The monomer (m31) can be synthesized by the method described in, for example, Prog. Polym. Sci., Vol. 12, 1986, pp. 233-237; US Pat. No. 4,330,654; and the like.

[0067] [ka]

[0068] Q 1 , Q 2 , Y and q are the Q 1 , Q 2 , Y and q.

[0069] The monomer (m32) corresponds to the unit (u32). As the monomer (m32), the monomers (m32-1) to (m32-3) are preferred, and the monomer (m32-1) is particularly preferred, since the polymer (H) can be easily produced and industrially implemented.

[0070] [ka]

[0071] The monomer (m32) can be synthesized by the method described in, for example, WO 2007 / 013533 pamphlet, JP 2008-202039 A, and the like.

[0072] (cyclic monomer) The unit (u11) is obtained by polymerizing the monomer (m11), and preferred embodiments of the monomer (m11) include the monomers (m11-1) to (m11-4). The monomer (m11) can be synthesized by a known method. In formula (m11), R 11 ~R 16 are the R in equation (u11), respectively. 11 ~R 16 is synonymous with.

[0073] [ka]

[0074] The unit (u12) is obtained by polymerizing the monomer (m12), and preferred embodiments of the monomer (m12) include the monomers (m12-1) and (m12-2). The monomer (m12) can be synthesized by a known method. R in equation (m12) 21 and R 22 are the R in equation (u12), respectively. 21 and R 22 is synonymous with.

[0075] [ka]

[0076] The unit (u21) is obtained by polymerizing the monomer (m21), and preferred embodiments of the monomer (m21) include the monomers (m21-1) and (m21-2). The monomer (m21) can be synthesized by a known method. R in equation (m21) 41 ~R 46 are the R in equation (u21), respectively. 41 ~R 46 is synonymous with.

[0077] [ka]

[0078] The unit (u22) is obtained by polymerizing the monomer (m22), and preferred embodiments of the monomer (m22) include the monomers (m22-1) to (m22-11). The monomer (m22) can be synthesized by a known method. R in equation (m22) 51 ~R 55 and s are the R 51 ~R 55 and s.

[0079] [ka]

[0080] The unit (u24) is obtained by cyclopolymerizing the monomer (m24), and preferred embodiments of the monomer (m24) include the monomers (m24-1) to (m24-3). The monomer (m24) can be synthesized by a known method. R in equation (m24) 71 ~R 76 are the R in equation (u24), respectively. 71 ~R 76 is synonymous with.

[0081] CF(R 71 )=C(R 73 )-O-CF(R 76 )-CF(R 75 )-C(R 74 )=CF(R 72 ) (m24) CF2=CF-O-CF2-CF2-CF=CF2(m24-1) CF2=CF-O-CF2-CF(CF3)-CF=CF2(m24-2) CF2=CF-O-CF(CF3)-CF2-CF=CF2(m24-3)

[0082] (Monomers having two or more polymerizable unsaturated bonds) An example of the monomer having two or more polymerizable unsaturated bonds is the monomer (m41). (CF2=CF)2Q 4 (m41)

[0083] The monomer (m41) corresponds to the unit (u41). Q in equation (m41) 4 is Q in equation (u41). 4 is synonymous with.

[0084] The monomer (m41) is preferably the monomers (m41-1) to (m41-3). CF2=CF-O-CF=CF2(m41-1) CF2=CF-O-(CF2) m1 -O-CF=CF2(m41-2) CF2=CF-[OCF2CF(CF3)] m2 -O-(CF2) m3 -[OCF(CF3)CF2] m4 -O-CF=CF2(m41-3)

[0085] The monomers (m41-1) to (m41-3) correspond to the units (u41-1) to (u41-3), respectively. m1 in formula (m41-2) has the same meaning as m1 in formula (u41-2). In formula (m41-3), m2, m3, and m4 have the same meanings as m2, m3, and m4 in formula (u41-3), respectively.

[0086] As an example of a method for converting a precursor group of an ion exchange group into an ion exchange group, a case where the precursor group of an ion exchange group is -SO2F will be explained. The group represented by -SO2F is a sulfonic acid group (-SO3 - H + ), for example, the following method (i) can be mentioned, in which a group represented by -SO2F is converted into a sulfonimide group (-SO2N(SO2R f ) - H + ) can be converted to, for example, the following method (ii). (i) A method in which a group represented by -SO2F is hydrolyzed to form a sulfonate, and the sulfonate is converted into an acid form to convert it into a sulfonic acid group. (ii) A method in which a group represented by -SO2F is imidized to form a salt-type sulfonimide group, and then further converted to an acid-type sulfonimide group by converting it to an acid-type sulfonimide group.

[0087] Method (i): Hydrolysis is carried out, for example, by contacting a precursor polymer having a group represented by -SO2F with a basic compound in a solvent. Examples of basic compounds include sodium hydroxide and potassium hydroxide. Examples of solvents include water and mixed solvents of water and polar solvents. Examples of polar solvents include alcohols (e.g., methanol, ethanol), dimethyl sulfoxide, etc. The conversion to an acid form is carried out, for example, by contacting the polymer having a sulfonate with an aqueous solution of hydrochloric acid, sulfuric acid, or the like. The hydrolysis and conversion to an acid form are usually carried out at 0 to 120°C.

[0088] Method (ii): The imidization may be carried out, for example, by the following method. (ii-1) A group represented by -SO2F and R f How to react with SO2NHM. (ii-2) In the presence of an alkali metal hydroxide, an alkali metal carbonate, MF, ammonia, or a primary to tertiary amine, a group represented by -SO2F and R f How to react with SO2NH2. (ii-3) A group represented by -SO2F and R f A method of reacting with SO2NMSi(CH3)3. Here, M is an alkali metal or primary to quaternary ammonium. The conversion to an acid form is carried out by treating a polymer having a salt form of sulfonimide group with an acid (sulfuric acid, nitric acid, hydrochloric acid, etc.).

[0089] Polymer (H) in which the ion exchange group is a sulfonimide group can also be produced by polymerizing a monomer in which the group represented by —SOF in monomer (m11), (m12), (m31), or (m32) has been converted to a sulfonimide group, with monomer (m21) or monomer (m22). A monomer in which the group represented by -SO2F has been converted into a sulfonimide group can be produced by adding chlorine or bromine to the carbon-carbon double bond of monomer (m11), (m12), (m31) or (m32), converting the group represented by -SO2F into a sulfonimide group by method (ii), and then carrying out a dechlorination or debromination reaction using metallic zinc.

[0090] [Membrane electrode assembly] The membrane electrode assembly of the present invention is a membrane electrode assembly comprising: an anode having a catalyst layer containing an electrolyte material made of a catalyst and a polymer having ion exchange groups; a cathode having a catalyst layer containing an electrolyte material made of a catalyst and a polymer having ion exchange groups; and a solid polymer electrolyte membrane disposed between the anode and the cathode and containing a fluorinated polymer having ion exchange groups. At least one of the electrolyte material contained in the anode and the electrolyte material contained in the cathode is an electrolyte material made of the polymer (H) described above.

[0091] 1 is a cross-sectional view showing an example of a membrane electrode assembly of the present invention. The membrane electrode assembly 10 includes an anode 13 having a catalyst layer 11 and a gas diffusion layer 12, a cathode 14 having the catalyst layer 11 and the gas diffusion layer 12, and a solid polymer electrolyte membrane 15 disposed between the anode 13 and the cathode 14 in contact with the catalyst layer 11. In the following description, the anode and the cathode may be collectively referred to as "electrodes."

[0092] [Electrodes (anode and cathode)] The anode 13 and the cathode 14 each have a catalyst layer 11 and a gas diffusion layer 12 .

[0093] <Catalyst layer> The electrolyte material contained in at least one of the catalyst layer 11 of the anode 13 and the catalyst layer 11 of the cathode 14 may be an electrolyte material made of polymer (H), and both may be electrolyte materials made of polymer (H). When the electrolyte material contained in one catalyst layer 11 is an electrolyte material made of polymer (H) and the electrolyte material contained in the other catalyst layer 11 is not an electrolyte material made of polymer (H), the proton-conductive polymer contained in the latter catalyst layer 11 is preferably polymer (S) described below. In the membrane / electrode assembly of the present invention, from the viewpoint of gas permeability, it is preferable that the electrolyte material contained in at least the cathode is an electrolyte material made of polymer (H).

[0094] The thickness of the catalyst layer is preferably 1 to 20 μm, particularly preferably 3 to 10 μm, from the viewpoint of facilitating gas diffusion in the catalyst layer and further improving the power generation performance of the polymer electrolyte fuel cell. The thickness of the catalyst layer is a value measured by observing the cross section of the catalyst layer with a scanning electron microscope or the like, and means the arithmetic mean value of 10 arbitrary points.

[0095] (catalyst) The catalyst contained in the catalyst layer may be, for example, a supported catalyst in which platinum or a platinum alloy is supported on a carbon support. Specific examples of the carbon support include carbon black powder, graphitized carbon, carbon fiber, and carbon nanotubes. The platinum alloy is preferably an alloy of platinum with at least one metal selected from the group consisting of platinum group metals excluding platinum (ruthenium, rhodium, palladium, osmium, iridium), gold, silver, chromium, iron, titanium, manganese, cobalt, nickel, molybdenum, tungsten, aluminum, silicon, zinc, and tin. When a supported catalyst is used, the amount of the catalyst supported is preferably 10 to 80 mass %, particularly preferably 10 to 70 mass %, based on the total mass of the supported catalyst, from the viewpoints of better power generation efficiency of the fuel cell and cost.

[0096] <Gas diffusion layer> The gas diffusion layer 12 has the function of diffusing gas uniformly in the catalyst layer 11 and also functions as a current collector. Examples of the gas diffusion layer 12 include carbon paper, carbon cloth, and carbon felt. The gas diffusion layer 12 is preferably treated with polytetrafluoroethylene or the like to be water-repellent. Although the membrane electrode assembly 10 in FIG. 1 includes a gas diffusion layer 12, the gas diffusion layer is an optional component and does not necessarily need to be included in the membrane electrode assembly.

[0097] <Other components> The anode 13 and the cathode 14 may have other components in addition to those described above. A specific example of the other member is a carbon layer (not shown) provided between the catalyst layer 11 and the gas diffusion layer 12. The provision of the carbon layer improves the gas diffusion properties on the surface of the catalyst layer 11, thereby further improving the power generation performance of the fuel cell. The carbon layer contains, for example, carbon and a nonionic fluorine-containing polymer. A specific example of the carbon is preferably carbon nanofiber having a fiber diameter of 1 to 1000 nm and a fiber length of 1000 μm or less. A specific example of the nonionic fluorine-containing polymer is polytetrafluoroethylene.

[0098] <Method for forming catalyst layer> The catalyst layer 11 can be formed by a known method.

[0099] [Solid polymer electrolyte membrane] The solid polymer electrolyte membrane 15 is a fluorine-containing polymer (hereinafter also referred to as "polymer (S)") having an ion-exchange group. The polymer (S) may be any polymer having an ion exchange group and a fluorine atom, but from the viewpoint of high chemical durability, it preferably has units based on the above-mentioned perfluoromonomer that can be contained in the polymer (H). Specific examples of the unit based on a perfluoromonomer in the polymer (S) include the unit (u31) and the unit (u32), and the unit (u32) is particularly preferred in terms of better power generation characteristics of the fuel cell.

[0100] The content of units based on perfluoromonomers is preferably from 5 to 40 mol %, more preferably from 10 to 35 mol %, and particularly preferably from 15 to 30 mol %, based on all units contained in the polymer (S). The polymer (S) may contain only one type of unit based on a perfluoromonomer, or may contain two or more types. When two or more types are contained, the above content means the total amount thereof.

[0101] The polymer (S) may further comprise units based on tetrafluoroethylene (TFE). The content of units based on tetrafluoroethylene is preferably from 50 to 90 mol %, more preferably from 60 to 85 mol %, and particularly preferably from 65 to 80 mol %, based on all units contained in the polymer (S).

[0102] The polymer (S) may contain units other than those mentioned above (hereinafter also referred to as "other units"). Specific examples of such units are the same as the other units in the polymer (H).

[0103] The ion exchange capacity of the polymer (S) is preferably 1.10 to 3.0 meq / g dry resin, more preferably 1.20 to 3.0 meq / g dry resin, and particularly preferably 1.25 to 2.5 meq / g dry resin. If the ion exchange capacity is equal to or greater than the lower limit of the above range, the ionic conductivity of the polymer (S) is increased, and therefore sufficient cell output can be obtained when the membrane electrode assembly is applied to a polymer electrolyte fuel cell. If the ion exchange capacity is equal to or less than the upper limit of the above range, swelling of the polymer (S) when it absorbs water is suppressed, and the mechanical strength of the solid polymer electrolyte membrane is increased. Flooding in the polymer electrolyte fuel cell can be suppressed. The ion exchange capacity of the polymer (S) can be determined by the method described in the Examples section below.

[0104] The TQ value of the precursor polymer (S) of the polymer (S) is preferably from 200 to 350°C, more preferably from 210 to 340°C, and particularly preferably from 220 to 330°C. When the TQ value is equal to or greater than the lower limit of the above range, the polymer (S) has a sufficient molecular weight and is excellent in mechanical strength. When the TQ value is equal to or less than the upper limit of the above range, the solubility or dispersibility of the polymer (S) is improved, making it easy to prepare a liquid composition containing the polymer (S). The TQ value of the precursor polymer (S) is measured by the method described in the Examples section below.

[0105] (Method for producing polymer (S)) The polymer (S) can be produced, for example, by polymerizing a monomer having a precursor group of an ion-exchange group to obtain a polymer, and then converting the precursor group into an ion-exchange group. Specific examples of monomers that can be used in the production of polymer (S) include monomer (m31), monomer (m32), tetrafluoroethylene, perfluoro(3-butenyl vinyl ether), perfluoro(allyl vinyl ether), perfluoro α-olefins (hexafluoropropylene, etc.), and perfluoro(alkyl vinyl ethers) that are exemplified in the production method of polymer (H). The method for converting the precursor group of the ion exchange group into the ion exchange group is the same as in the method for producing polymer (H).

[0106] <Other components> To further improve durability, the solid polymer electrolyte membrane 15 may contain one or more atoms selected from the group consisting of cerium and manganese. Cerium and manganese decompose hydrogen peroxide, a substance that causes deterioration of the solid polymer electrolyte membrane 15. Cerium and manganese are preferably present in the solid polymer electrolyte membrane 15 as ions, but may also be present as sparingly soluble salts, such as cerium oxide. The solid polymer electrolyte membrane 15 may contain silica or heteropolyacid (zirconium phosphate, phosphomolybdic acid, phosphotungstic acid, etc.) as a water-retaining agent to prevent drying.

[0107] The solid polymer electrolyte membrane 15 may be reinforced with a reinforcing material. Examples of the reinforcing material include a porous body, fiber, woven fabric, and nonwoven fabric. Examples of the reinforcing material include polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer, polyethylene, polypropylene, and polyphenylene sulfide.

[0108] <Method for forming a solid polymer electrolyte membrane> The solid polymer electrolyte membrane 15 can be formed, for example, by a method (casting method) in which a liquid composition containing the polymer (S) is applied onto the substrate film or catalyst layer 11 and dried. The liquid composition is a dispersion in which the polymer (S) is dispersed in a solvent containing at least one of an organic solvent and water.

[0109] [Method for manufacturing membrane electrode assembly] The membrane electrode assembly 10 is produced, for example, by the following method. (i) A method in which a catalyst layer 11 is formed on a solid polymer electrolyte membrane 15 to form a membrane catalyst layer assembly, and the membrane catalyst layer assembly is sandwiched between gas diffusion layers 12. (ii) A method in which a catalyst layer 11 is formed on a gas diffusion layer 12 to form electrodes (anode 13, cathode 14), and a solid polymer electrolyte membrane 15 is sandwiched between the electrodes.

[0110] [Polymer electrolyte fuel cell] The polymer electrolyte fuel cell of the present invention includes the above-described membrane electrode assembly. The polymer electrolyte fuel cell of the present invention includes the above-mentioned membrane electrode assembly, and therefore has excellent power generation efficiency. The polymer electrolyte fuel cell of the present invention may have separators on both sides of the membrane electrode assembly, each having grooves formed therein to serve as gas flow paths. Specific examples of the separator include a metal separator, a carbon separator, a separator made of a material in which graphite and resin are mixed, and separators made of various conductive materials. In a polymer electrolyte fuel cell, power is generated by supplying a gas containing oxygen to the cathode and a gas containing hydrogen to the anode. The above-described membrane electrode assembly can also be applied to a methanol fuel cell, which generates electricity by supplying methanol to the anode. [Example]

[0111] The present invention will be described in detail below with reference to examples. Examples 1-1 to 1-9 are preparation examples, Examples 2-1 to 2-7 are working examples, and Examples 2-8 and 2-9 are comparative examples. However, the present invention is not limited to these examples.

[0112] [Content of each unit in the polymer] The content (mol %) of each unit contained in polymer (H) was calculated from the amount of each monomer used in producing polymer (F). The content of each unit in polymer (H) is the same as the content of the corresponding unit in polymer (F).

[0113] [Ion exchange capacity] Polymer (F) was vacuum-dried at 210°C for 16 hours. The dried polymer (F) was weighed and placed in a polycarbonate container. The dried polymer (F) was then immersed in a 0.7 N sodium hydroxide solution (solvent: water / methanol = 10 / 90 (mass ratio)) at 60°C for 72 hours or more, thereby completely converting the -SOF groups of the dried polymer (F) to the Na salt form. The sodium hydroxide solution in which the dried polymer (F) had been immersed was back-titrated with 0.1 mol / L hydrochloric acid using phenolphthalein as an indicator to determine the amount of sodium hydroxide in the solution, and the ion exchange capacity (milliequivalents / g dry resin, meq / g) was calculated. The ion exchange capacity of polymer (H) is the same as the ion exchange capacity measured using polymer (F), which is the precursor polymer.

[0114] [TQ value] Using a flow tester (Shimadzu Corporation, CFT-500A) equipped with a nozzle having a length of 1 mm and an inner diameter of 1 mm, polymer (F), which is the polymer before hydrolysis treatment of polymer (H), was melt-extruded while changing the temperature under the condition of an extrusion pressure of 2.94 MPa (gauge pressure). 3 The temperature at which the extrusion rate reaches 1 / s (TQ value) was determined. For the same composition, the higher the TQ value, the higher the molecular weight of the polymer. When the TQ value exceeds 300°C, the extrusion rate at 300°C (Q value: mm 3 / sec, 300°C).

[0115] [monomer] The monomers used in the following preparation examples are as follows:

[0116] <Monomer corresponding to unit A> Tetrafluoroethylene (TFE)

[0117] <Monomer corresponding to unit B> Monomer (m32-1)

[0118] [ka]

[0119] Monomer (m31-4)

[0120] [ka]

[0121] Monomer (m31-5) CF2=CFOCF2CF2SO2F (m31-5)

[0122] <Monomer corresponding to unit C> Monomer (m22-1)

[0123] [ka]

[0124] Monomer (m24-1)

[0125] [ka]

[0126] Monomer (m21-1)

[0127] [ka]

[0128] <Monomer corresponding to unit D> ·C4-DVE:CF2=CF-O-(CF2)4-O-CF=CF2 ·C3-DVE:CF2=CF-O-(CF2)3-O-CF=CF2

[0129] [Radical polymerization initiator] The radical polymerization initiators used in the following preparation examples are as follows: ·PFB:CF3CF2CF2C(=O)OOC(=O)CF2CF2CF3 ·IPP:(CH3)2CHOC(=O)OOC(=O)OCH(CH3)2 ·V-601:Dimethyl 2,2'-azobis(2-methylpropionate)

[0130] [solvent] The solvents used in the following preparation examples are as follows.

[0131] HFC-52-13p:CF3(CF2)4CF2H HCFC-225cb: CClF2CF2CHClF HFE-347pc-f:CF3CH2OCF2CF2H MeOH:CH3OH EtOH:C2H5OH

[0132] [Example 1-1: Preparation example] <Synthesis of Polymer (F-1)> A 230 mL stainless steel reactor was charged with 97.4 g of monomer (m32-1), 17.1 g of monomer (m22-1), and 0.06 g of C4-DVE, and 1.58 g of a solution of HFC-52-13p in which the radical initiator PFB had been dissolved to a concentration of 2.39 mass% was added. After charging, the mixture was thoroughly frozen and degassed using liquid nitrogen. Thereafter, 9.11 g of TFE was charged, stirred at 100 rpm, and heated to 24°C to initiate polymerization. The pressure at the start of polymerization was 0.32 MPaG. The internal temperature was maintained at 24°C and the reaction was continued for 24 hours, after which the system was cooled and the gas in the system was purged to terminate the polymerization. The pressure at the end of the reaction was 0.02 MPaG. Thereafter, the remaining monomer (m22-1) was distilled off at 24°C under reduced pressure for 3 hours to obtain a polymer solution. The resulting polymer solution was diluted with 202 g of HFC-52-13p, and then 89.6 g of MeOH was added to flocculate the polymer, which was then filtered. The polymer was then washed three times with a mixed solvent of HFC-52-13p / MeOH = 2 / 1 (mass ratio). The polymer was dried in vacuo at 210 °C for 16 hours, yielding 31.7 g of polymer (F-1). The ion exchange capacity was 1.39 meq / g dry resin.

[0133] <Preparation of Polymer (H-1)> Polymer (F-1) was contacted with a reaction liquid containing 15% by mass of potassium hydroxide, 20% by mass of MeOH, and 65% by mass of ultrapure water at 80°C for 48 hours to hydrolyze the -SO2F groups in the polymer and convert them to -SO3K groups. After separation by filtration, the polymer was immersed in ultrapure water at 80°C to rinse off the alkali. Next, the polymer was immersed in a 3N aqueous hydrochloric acid solution at 80°C for 0.5 hours, separated by filtration, immersed in ultrapure water at 80°C, and filtered after 0.5 hours. This procedure was repeated a total of eight times to convert the -SO3K groups in the polymer to sulfonic acid groups. Subsequently, the polymer was repeatedly washed with ultrapure water until the pH of the water in which it was immersed reached 7. During the acidification process, the polymer was immersed in 10% by mass of hydrogen peroxide solution at 80°C for 16 hours. The polymer was then dried at room temperature under a nitrogen atmosphere to obtain Polymer (H-1).

[0134] <Preparation of Liquid Composition (D-1)> 14.0 g of polymer (H-1), 68.9 g of EtOH, and 44.2 g of ultrapure water (ultrapure water / EtOH = 40 / 60 (mass ratio)) were placed in a 0.2 L glass autoclave, sealed, and mixed and stirred at 115 ° C. for 6 hours at 300 rpm using a double helical impeller, then cooled and filtered using a pressure filter (filter paper: Advantec Toyo Co., Ltd., PF040) to obtain a liquid composition (D-1) in which polymer (H-1) was uniformly dispersed in the mixed solvent. The solid content of the resulting liquid composition was 11.1 mass%.

[0135] [Example 1-2: Preparation example] <Synthesis of Polymer (F-2)> A 230 mL stainless steel reactor was charged with 97.4 g of monomer (m32-1), 17.2 g of monomer (m22-1), and 0.13 g of C4-DVE, and 36.1 mg of IPP, a radical polymerization initiator, was added. After charging, the mixture was thoroughly frozen and degassed using liquid nitrogen. Thereafter, 9.12 g of TFE was charged, stirred at 100 rpm, and heated to 40°C to initiate polymerization. The pressure at the start of polymerization was 0.42 MPaG. The internal temperature was maintained at 40°C and the reaction was continued for 24 hours, after which the system was cooled and the gas in the system was purged to terminate the polymerization. The pressure at the end of the reaction was 0.07 MPaG. Thereafter, the remaining monomer (m22-1) was distilled off at 40°C under reduced pressure for 3 hours to obtain a polymer solution. The resulting polymer solution was diluted with 204 g of HFC-52-13p, and then 154 g of MeOH was added to flocculate the polymer, which was then filtered. The polymer was then washed three times with a mixed solvent of HFC-52-13p / MeOH = 2 / 1 (mass ratio). The polymer was dried in vacuo at 210 °C for 16 hours, yielding 23.3 g of polymer (F-2). The ion exchange capacity was 1.54 meq / g dry resin.

[0136] <Preparation of Polymer (H-2) and Liquid Composition (D-2)> A polymer (H-2) and a liquid composition (D-2) were obtained in the same manner as in Example 1-1, except that the polymer (F-2) was used instead of the polymer (F-1).

[0137] [Example 1-3: Preparation example] <Synthesis of Polymer (F-3)> A 495 mL stainless steel reactor was charged with 428 g of monomer (m31-4), 63.4 g of monomer (m22-1), and 0.27 g of C4-DVE, and 148 mg of IPP, a radical polymerization initiator, was added. After charging, the mixture was thoroughly frozen and degassed using liquid nitrogen. Then, 14.6 g of TFE was added, stirred at 100 rpm, and heated to 40°C to initiate polymerization. The internal temperature was maintained at 40°C, and the reaction was continued for 24 hours. After that, the reaction was cooled and the gas in the system was purged to terminate the polymerization. The remaining monomer (m22-1) was then distilled off at 24°C under reduced pressure for 3 hours to obtain a polymer solution. The resulting polymer solution was diluted with HCFC-225cb, and then hexane was added to flocculate the polymer, which was then filtered. The polymer was then washed three times with hexane. The polymer was dried in vacuo at 210°C for 16 hours, yielding 83.0 g of polymer (F-3). The ion exchange capacity was 1.16 meq / g dry resin.

[0138] <Preparation of Polymer (H-3) and Liquid Composition (D-3)> Polymer (H-3) and liquid composition (D-3) were obtained in the same manner as in Example 1-1, except that polymer (F-3) was used instead of polymer (F-1).

[0139] [Example 1-4: Preparation example] <Synthesis of Polymer (F-4)> A 495 mL stainless steel reactor was charged with 398 g of monomer (m31-5), 93.9 g of monomer (m22-1), and 0.40 g of C4-DVE. 148 mg of the radical polymerization initiator IPP was added, and the mixture was thoroughly frozen and degassed using liquid nitrogen. Then, 21.6 g of TFE was added, stirred at 100 rpm, and the temperature was raised to 40 °C to initiate polymerization. The internal temperature was maintained at 40 °C, and the reaction was continued for 24 hours. The system was then cooled and the gas in the system was purged to terminate the polymerization. The remaining monomer (m22-1) was then distilled off at 24 °C under reduced pressure for 3 hours, yielding a polymer solution. The resulting polymer solution was diluted with HCFC-225cb, and then hexane was added to flocculate the polymer, which was then filtered. The polymer was then washed three times with hexane. The polymer was dried in vacuo at 210°C for 16 hours, yielding 83.0 g of polymer (F-4). The ion exchange capacity was 1.44 meq / g dry resin.

[0140] <Preparation of Polymer (H-4) and Liquid Composition (D-4)> Polymer (H-4) and liquid composition (D-4) were obtained in the same manner as in Example 1-1, except that polymer (F-4) was used instead of polymer (F-1).

[0141] [Example 1-5: Preparation example] <Synthesis of Polymer F> A 230 mL stainless steel reactor was charged with 78.9 g of monomer (m32-1), 31.1 g of monomer (m24-1), 0.06 g of C4-DVE, and 37.0 g of HFC-52-13p as a polymerization medium, and the mixture was thoroughly frozen and degassed using liquid nitrogen. The mixture was then stirred at 230 rpm, heated to 40°C, and charged with 4.20 g of TFE. A mixture of 45.5 mg of IPP (a radical polymerization initiator) and 3.00 g of HFC-52-13p was pressurized into the reactor to initiate polymerization. TFE was continuously added while maintaining the initiation pressure. The reaction was continued for 6 hours, and when the amount of TFE continuously introduced reached 4.65 g, the reactor was cooled and the gas in the system was purged to terminate the polymerization, yielding a polymer solution. The resulting polymer solution was diluted with HFC-52-13p, and then HFE-347pc-f was added to flocculate the polymer, which was then filtered. This process of adding HFE-347pc-f, stirring, washing, and filtering was repeated twice. The polymer was dried in vacuo at 210°C for 16 hours, yielding 10.1 g of polymer (F-5). The ion exchange capacity was 1.29 meq / g dry resin.

[0142] <Preparation of Polymer (H-5) and Liquid Composition (D-5)> A polymer (H-5) and a liquid composition (D-5) were obtained in the same manner as in Example 1-1, except that the polymer (F-5) was used instead of the polymer (F-1).

[0143] [Example 1-6: Preparation example] <Synthesis of Polymer F> A 230 mL stainless steel reactor was charged with 67.8 g of monomer (m32-1), 4.81 g of monomer (m21-1), 0.04 g of C4-DVE, and 87.6 g of HCFC-225cb as the polymerization medium. 40.1 mg of IPP, a radical polymerization initiator, was added. After charging, the mixture was thoroughly frozen and degassed using liquid nitrogen. Then, 6.90 g of TFE was added, stirred at 200 rpm, and heated to 40 ° C to initiate polymerization. The internal temperature was maintained at 40 ° C, and the reaction was continued for 6.3 hours. After that, the mixture was cooled and the gas in the system was purged to terminate the polymerization. The remaining monomer (m21-1) was then distilled off at 24 ° C under reduced pressure for 3 hours, yielding a polymer solution. The resulting polymer solution was diluted with HCFC-225cb, and then hexane was added to flocculate the polymer, which was then filtered. The polymer was then washed three times with hexane. The polymer was dried in vacuo at 210°C for 16 hours, yielding 21.7 g of polymer (F-6). The ion exchange capacity was 1.39 meq / g dry resin.

[0144] <Preparation of Polymer (H-6) and Liquid Composition (D-6)> A polymer (H-6) and a liquid composition (D-6) were obtained in the same manner as in Example 1-1, except that the polymer (F-6) was used instead of the polymer (F-1).

[0145] [Example 1-7: Preparation example] <Synthesis of Polymer (F-7)> A 230 mL stainless steel reactor was charged with 97.4 g of monomer (m32-1), 17.1 g of monomer (m22-1), and 0.05 g of C3-DVE, and 1.57 g of a solution of HFC-52-13p in which PFB, the radical polymerization initiator, had been dissolved to a concentration of 2.39 mass%, was added. After charging, the mixture was thoroughly frozen and degassed using liquid nitrogen. Then, 9.00 g of TFE was charged, stirred at 100 rpm, and heated to 24 ° C to initiate polymerization. The internal temperature was maintained at 24 ° C and the reaction was continued for 24 hours, after which the system was cooled and the gas in the system was purged to terminate the polymerization. Thereafter, the remaining monomer (m22-1) was distilled off at 24 ° C under reduced pressure for 3 hours to obtain a polymer solution. The resulting polymer solution was diluted with HFC-52-13p, and MeOH was added to coagulate the polymer, which was then filtered. The polymer was then washed three times with a mixed solvent of HFC-52-13p / MeOH = 2 / 1 (mass ratio). The polymer was dried in vacuo at 210 °C for 16 hours to obtain 30.0 g of polymer (F-7). The ion exchange capacity was 1.39 meq / g dry resin.

[0146] <Preparation of Polymer (H-7) and Liquid Composition (D-7)> Polymer (H-7) and liquid composition (D-7) were obtained in the same manner as in Example 1-1, except that polymer (F-7) was used instead of polymer (F-1).

[0147] [Example 1-8: Preparation example] (Synthesis of Polymer (F-8)) A 495 mL stainless steel reactor was charged with 226 g of monomer (m32-1) and 39.0 g of monomer (m22-1), and 3.00 g of a solution of HFC-52-13p in which PFB, a radical polymerization initiator, had been dissolved so that the concentration was 2.68 mass % was added. After charging, the mixture was thoroughly frozen and degassed using liquid nitrogen. Then, 11.0 g of TFE was charged, stirred at 100 rpm, and heated to 22 ° C to initiate polymerization. The internal temperature was maintained at 22 ° C and the reaction was continued for 24 hours, after which the system was cooled and the gas in the system was purged to terminate the polymerization. Thereafter, the remaining monomer (m22-1) was distilled off at 24 ° C under reduced pressure for 3 hours to obtain a polymer solution. The resulting polymer solution was diluted with HFC-52-13p and then poured into a mixed solvent of HFC-52-13p / MeOH = 80 / 20 (mass ratio) to coagulate the polymer, which was then filtered. The polymer was then washed three times with a mixed solvent of HFC-52-13p / MeOH = 50 / 50 (mass ratio). The polymer was dried in vacuo at 210 °C for 16 hours to obtain 58.7 g of polymer (F-8). The ion exchange capacity was 1.46 meq / g dry resin.

[0148] <Preparation of Polymer (H-8)> Polymer (H-8) was obtained in the same manner as in Example 1-1, except that polymer (F-8) was used instead of polymer (F-1) and the filtration operation was carried out a total of 10 times.

[0149] <Preparation of Liquid Composition (D-8)> 23.0 g of polymer (H-8), 48.5 g of EtOH, and 48.5 g of ultrapure water (ultrapure water / EtOH = 50 / 50 (mass ratio)) were placed in a 0.2 L glass autoclave, sealed, and mixed and stirred at 110 ° C. for 6 hours at 300 rpm using a double helical impeller, then cooled and filtered (filter: Advantec Toyo Co., Ltd., TCP-10V) to obtain a liquid composition (D-8) in which polymer (H-8) was uniformly dispersed in the mixed solvent. The solid content of the resulting liquid composition was 19.3 mass%.

[0150] [Example 1-9: Preparation example] <Synthesis of Polymer (F-9)> A 230 mL stainless steel reactor was charged with 75.0 g of the monomer (m32-1), 0.05 g of C4-DVE, and 92.3 g of HFC-52-13p as a polymerization medium, and the contents were thoroughly frozen and degassed using liquid nitrogen. The mixture was then stirred at 230 rpm and heated to 70°C, at which point TFE was added until the pressure reached 0.71 MPaG. A mixture of 51.0 mg of initiator V-601 and 2.74 g of HFC-52-13p was pressurized into the reactor to initiate polymerization. TFE was continuously added while maintaining the pressure at 0.71 MPaG. The reaction was continued for 6 hours, and when the amount of TFE continuously introduced reached 18.2 g, the reactor was cooled and the gas in the system was purged to terminate the polymerization, yielding a polymer solution. The resulting polymer solution was diluted with 100 g of HFC-52-13p, and then 400 g of HFE-347pc-f was added to flocculate the polymer, which was then filtered. This procedure of adding 250 g of HFE-347pc-f, stirring, washing, and filtering was repeated twice. The resulting solution was dried in vacuo at 240°C for 16 hours, yielding 32.0 g of polymer (F-9).

[0151] <Preparation of Polymer (H-9) and Liquid Composition (D-9)> A polymer (H-9) and a liquid composition (D-9) were obtained in the same manner as in Example 1-1, except that the polymer (F-9) was used instead of the polymer (F-1).

[0152] Table 1 shows the ion exchange capacity, TQ value or Q value, and the content (mol %) of each unit in the polymer.

[0153] [Table 1]

[0154] [Example 2-1] A liquid composition (solid content = 28.0 mass %, ethanol / water = 60 / 40 (mass ratio)) in which an acid-type sulfonic acid group-containing fluoropolymer having an ion exchange capacity of 1.25 meq / g dry resin was dispersed was obtained using the method described in Example 8 (ion exchange resin liquid AV1) of Japanese Patent No. 6468475. The liquid composition was applied to an ethylene-tetrafluoroethylene copolymer sheet using a die coater while adjusting the coating amount of the liquid composition so that the film thickness was 25 μm, dried at 80°C, and further heat-treated at 160°C for 30 minutes to obtain a 25 μm-thick electrolyte membrane for battery evaluation. 18.61 g of water, 9.66 g of ethanol, 5.86 g of liquid composition (D-1), and 100 g of zirconia beads with a diameter of 5 mm were added to 3.0 g of a supported catalyst (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., product name: TEC10E50E) in which 50% platinum was supported on carbon powder, and the mixture was uniformly dispersed in a planetary bead mill at 300 rpm for 90 minutes. 24.67 g of water and 16.44 g of ethanol were added to the mixture, and the mixture was further dispersed in a planetary bead mill at 300 rpm for 90 minutes to obtain a coating solution for forming a cathode catalyst layer with a solids content of 8% by mass. The coating solution for forming a cathode catalyst layer was applied to the electrolyte membrane for battery evaluation with an applicator, dried at 80°C, and further heat-treated at 160°C for 30 minutes, resulting in a platinum content of 0.2 mg / cm. 2 An electrolyte membrane with a cathode catalyst layer was prepared. A liquid composition (D-10) (solid content concentration = 26.0 mass%, ethanol / water = 60 / 40 (mass ratio)) in which an acid-type sulfonic acid group-containing fluoropolymer having an ion exchange capacity of 1.1 milliequivalents / gram dry resin is dispersed was obtained using the method described in Example 4 of JP 2018-55877 A. 117 g of water was added to 20.0 g of a supported catalyst (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., product name: TEC10E50E) in which 50% by mass of platinum was supported on carbon powder, and the mixture was uniformly dispersed using ultrasonic waves for 10 minutes. 30.8 g of the liquid composition described above was added thereto, and then 112 g of ethanol was added to obtain a coating liquid for forming a catalyst layer with a solid content of 10% by mass. The coating liquid for forming a catalyst layer was applied to an ethylene-tetrafluoroethylene copolymer sheet, dried at 80°C, and further subjected to heat treatment at 160°C for 30 minutes, resulting in a platinum content of 0.4 mg / cm. 2An anode catalyst layer sheet of the above was prepared. The anode catalyst layer of the anode catalyst layer sheet was placed on the cathode catalyst layer-free side of the previously obtained electrolyte membrane with a cathode catalyst layer, and the anode catalyst layer was bonded to the electrolyte membrane under the following heat-press conditions: 130°C, 2 minutes, 1.5 MPa. The ethylene-tetrafluoroethylene copolymer sheet was then peeled off to obtain an electrode with an area of ​​25 cm. 2 A membrane catalyst layer assembly of this size was obtained. The membrane / catalyst layer assembly was sandwiched between an anode gas diffusion substrate (manufactured by NOK Corporation, product name: X0086 IX92 CX320) and a cathode gas diffusion substrate (manufactured by NOK Corporation, product name: H2315 T10X6 CX96) to obtain a membrane / electrode assembly. The gas diffusion substrate had a carbon layer made of carbon particles and PTFE on one surface, and was positioned so that the carbon layer was in contact with the catalyst layer of the membrane / catalyst layer assembly.

[0155] [Example 2-2 to Example 2-9] A membrane / electrode assembly was obtained in the same manner as in Example 2-1, except that the liquid composition shown in Table 2 was used as the cathode catalyst layer coating fluid and the amounts of the liquid composition and solvent added were adjusted so that the composition of the cathode catalyst layer coating fluid did not change.

[0156] [Evaluation test] <Power generation characteristics> The obtained membrane electrode assemblies of Examples 2-1 to 2-9 were assembled into a power generation cell, and the temperature of the membrane electrode assembly was maintained at 80°C. Hydrogen gas (utilization rate 70%) was supplied to the anode, and air (utilization rate 50%) was supplied to the cathode, each pressurized to 151 kPa (absolute pressure). The gases were humidified to a relative humidity of 100% RH for both hydrogen and air, and the current density was 2 A / cm. 2 The cell voltage at this time was recorded and evaluated according to the following criteria. The higher the cell voltage, the better the power generation characteristics of the polymer electrolyte fuel cell. The evaluation results are shown in Table 2. ◎:0.58V or more 〇: 0.50V or more, less than 0.58V ×: Less than 0.50V

[0157] <Cracks in the catalyst layer> The electrolyte membrane with a cathode catalyst layer was imaged at 200x magnification using a digital microscope (Keyence, VHX-5000). Images were taken with and without transmitted light, shining light on the back side of the electrolyte membrane with a cathode catalyst layer as viewed from the lens. White spots that appeared only when transmitted light was present were judged to be cracks in the catalyst layer. The percentage of the area of ​​cracks in the catalyst layer relative to the entire field of view was calculated using image analysis software ImageJ, and evaluated according to the following criteria. The evaluation results are shown in Table 2. ◎: Less than 1% 〇: 1% or more, less than 3% ×: 3% or more

[0158] [Table 2]

[0159] As shown in Table 2, it was confirmed that by using a polymer having a unit based on tetrafluoroethylene, a unit not containing a cyclic ether structure but having an ion exchange group, a unit containing a cyclic ether structure, and a unit based on a monomer having two or more polymerizable unsaturated bonds, it is possible to suppress cracking of the catalyst layer and form a fuel cell with excellent power generation characteristics. The entire contents of the specification, claims, abstract and drawings of Japanese Patent Application No. 2021-055644, filed on March 29, 2021, are hereby incorporated by reference as the disclosure of the specification of the present invention. [Explanation of symbols]

[0160] 10 Membrane electrode assembly 11 Catalyst layer 12 Gas diffusion layer 13 Anode 14 cathode 15 Solid polymer electrolyte membrane

Claims

1. An electrolyte material made of a polymer having an ion exchange group, the polymer has a unit based on tetrafluoroethylene, a unit not containing a cyclic ether structure but having an ion exchange group, a unit containing a cyclic ether structure, and a unit based on a monomer having two or more polymerizable unsaturated bonds, the content of the units based on tetrafluoroethylene is 1 to 50 mol % based on all units contained in the polymer, the content of the units having an ion exchange group and not having a cyclic ether structure is 30 to 85 mol % based on the total units contained in the polymer; the content of the unit containing a cyclic ether structure is 1 to 50 mol % based on the total units contained in the polymer, the content of units based on the monomer having two or more polymerizable unsaturated bonds is 0.001 to 10 mol % based on all units contained in the polymer, the molar ratio of the content of units based on the monomer having two or more polymerizable unsaturated bonds to the content of units based on tetrafluoroethylene is 4.3×10 −4 to 9.9×10 −3 , an electrolyte material characterized in that the molar ratio of the content of units based on the monomer having two or more polymerizable unsaturated bonds to the content of units containing the cyclic ether structure is 6.7×10 −4 to 9.9×10 −3 .

2. 2. The electrolyte material according to claim 1, wherein the unit containing a cyclic ether structure is at least one unit selected from the group consisting of a unit represented by formula (u11), a unit represented by formula (u12), a unit represented by formula (u21), a unit represented by formula (u22), and a unit represented by formula (u24). 【Chemical 1】 In formula (u11), R １１ is a divalent perfluoroalkylene group which may have an ether-bonded oxygen atom, and R １２ , R １３ , R １５ and R １６ are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom, and R １４ represents a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom, a fluorine atom, or —R １１ (SO ２ X (SO ２ R ｆ ) ａ ) － M ＋ It is a group represented by the formula: M ＋ Is, H ＋ , a monovalent metal cation or an ammonium ion in which one or more hydrogen atoms may be substituted with a hydrocarbon group, and R ｆ represents a linear or branched perfluoroalkyl group which may have an ether-bonded oxygen atom, X represents an oxygen atom, a nitrogen atom or a carbon atom, and when X represents an oxygen atom, a=0; when X represents a nitrogen atom, a=1; and when X represents a carbon atom, a=2. In formula (u12), R ２１ is a perfluoroalkylene group having 1 to 6 carbon atoms or a perfluoroalkylene group having 2 to 6 carbon atoms and an ether-bonding oxygen atom between the carbon-carbon bonds, and R ２２ represents a fluorine atom, a perfluoroalkyl group having 1 to 6 carbon atoms, a perfluoroalkyl group having 2 to 6 carbon atoms and an ether-bonded oxygen atom between the carbon-carbon bonds, or -R ２１ (SO ２ X (SO ２ R ｆ ) ａ ) － M ＋ It is a group represented by the formula: M ＋ , R ｆ , X and a are the same as above. In formula (u21), R ４１ , R ４２ , R ４３ , R ４４ , R ４５ and R ４６ are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom. In formula (u22), s is 0 or 1, and R ５１ and R ５２ are each independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a spiro ring formed by linking together (when s is 0), and R ５３ and R ５４ are each independently a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and R ５５ is a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms. In formula (u24), R ７１ , R ７２ , R ７３ , R ７４ , R ７５ and R ７６ are each independently a monovalent perfluoroalkyl group which may have an ether-bonded oxygen atom or a fluorine atom.

3. The electrolyte material according to claim 2 , wherein the unit containing a cyclic ether structure is a unit represented by formula (u22).

4. The electrolyte material according to any one of claims 1 to 3, wherein the unit based on a monomer having two or more polymerizable unsaturated bonds is a unit represented by formula (u41): 【Chemistry 2】 In formula (u41), Q ４ is an oxygen atom or a divalent perfluoroalkylene group which may have an ether-bonding oxygen atom.

5. The unit based on a monomer having two or more polymerizable unsaturated bonds is at least one unit selected from the group consisting of a unit represented by formula (u41-1), a unit represented by formula (u41-2), and a unit represented by formula (u41-3). The electrolyte material according to claim 4. 【Chemistry 3】 In the formulae (u41-2) and (u41-3), m1 and m3 are integers of 2 to 8. In the formula (u41-3), m2 and m4 each independently represent an integer of 0 to 5, and m2+m4≧1.

6. The electrolyte material according to any one of claims 1 to 5, wherein the unit having an ion exchange group and not containing a cyclic ether structure is at least one of a unit represented by formula (u31) and a unit represented by formula (u32): 【Chemistry 4】 In formula (u31), Z is a fluorine atom or a trifluoromethyl group, q is 0 or 1, m is an integer of 0 to 3, p is 0 or 1, n is an integer of 1 to 12, m+p>0, and M ＋ Is, H ＋ , a monovalent metal cation, or an ammonium ion in which one or more hydrogen atoms may be substituted with a hydrocarbon group. In formula (u32), Q １ is a perfluoroalkylene group which may have an ether-bonded oxygen atom, and Q ２ represents a single bond or a perfluoroalkylene group which may have an ether bond oxygen atom, Y represents a fluorine atom or a monovalent perfluoroalkyl group, q represents 0 or 1, and R ｆ represents a linear or branched perfluoroalkyl group which may have an ether-bonded oxygen atom, X represents an oxygen atom, a nitrogen atom, or a carbon atom, and when X represents an oxygen atom, a=0, when X represents a nitrogen atom, a=1, and when X represents a carbon atom, a=2; R ｆ If there are multiple R ｆ They may be the same or different.

7. 7. The electrolyte material according to claim 1, wherein the ion exchange capacity of the polymer is 0.5 to 2.5 meq / g dry resin.

8. A membrane electrode assembly comprising: an anode having a catalyst layer containing an electrolyte material made of a catalyst and a polymer having ion exchange groups; a cathode having a catalyst layer containing an electrolyte material made of a catalyst and a polymer having ion exchange groups; and a solid polymer electrolyte membrane disposed between the anode and the cathode and containing a fluorine-containing polymer having ion exchange groups, 8. A membrane electrode assembly, wherein at least one of the electrolyte material contained in the anode and the electrolyte material contained in the cathode is the electrolyte material according to claim 1.

9. A polymer electrolyte fuel cell comprising the membrane electrode assembly according to claim 8.

Images