JP2009231218A - Membrane electrode assembly for stationary or portable fuel cell, stationary or portable fuel cell, and resin paste for gas diffusion layer of stationary or portable fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a membrane electrode assembly for a stationary or portable fuel cell suppressing peeling off of a gas diffusion layer to the operation stop of the fuel cell or variation of environment of the membrane electrode assembly such storage environment and enhancing durability. <P>SOLUTION: A gas diffusion layer on a cathode side contains a hydroxyl group-containing fluorine polymer having the following structural unit. [In formula (1), R<SP>1</SP>shows a fluorine atom, a fluoroalkyl group, or a group represented by -OR<SP>2</SP>(R<SP>2</SP>shows an alkyl group or a fluoroalkyl group), in formula (2), R<SP>3</SP>shows a hydrogen atom or a methyl group, R<SP>4</SP>shows an alkyl group or a group represented by -(CH<SB>2</SB>)<SB>x</SB>-OR<SP>5</SP>or -OCOR<SP>5</SP>(R<SP>5</SP>shows an alkyl group or a glycidyl group, and x is 0 or 1), a carboxyl group or an alkoxycarbonyl group, in formula (3), R<SP>6</SP>shows a hydrogen atom or a methyl group, R<SP>7</SP>shows a hydrogen atom or a hydroxyalkyl group, and v is 0 or 1]. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a membrane electrode assembly for a stationary or portable fuel cell, a stationary or portable fuel cell, and a resin paste for a gas diffusion layer of the stationary or portable fuel cell.

  A polymer electrolyte fuel cell is configured as a unit of a cell in which an anode and a cathode where a reaction responsible for power generation occurs and a polymer solid electrolyte membrane serving as a proton conductor between the anode and the cathode are sandwiched between separators.

  The electrode includes an electrode base material that promotes gas diffusion and collects current, and a catalyst layer that actually becomes an electrochemical reaction field. The catalyst layer is formed of an electrode electrolyte made of an ion exchange resin and carbon particles having catalyst fine particles such as platinum supported on the surface. Specifically, in the anode, the fuel gas reacts on the catalyst fine particles to generate protons and electrons, the electrons are conducted to the electrode substrate, and the protons move through the electrode electrolyte and are conducted to the polymer solid electrolyte membrane. On the other hand, at the cathode, the oxidizing gas, protons conducted from the polymer solid electrolyte membrane through the cathode electrode electrolyte, and electrons conducted from the electrode substrate react on the catalyst fine particles to generate water.

Thus, fuel cells are actively studied as the next generation power source because the product is only water and the energy exchange rate is high.
As ion-exchange resin electrolytes for fuel cells, Nafion (registered trademark; Patent Documents 1 and 2) manufactured by DuPont and sulfonated polyarylene (Patent Documents 3 and 4) are known.

  Here, in order to obtain high output in the fuel cell, it is necessary to perform the above reaction efficiently. As a method for efficiently supplying reactants to the catalyst layer, discharging the product from the catalyst layer, and conducting electrons between the catalyst layer and the separator efficiently, for example, carbon paper treated with water repellent with polytetrafluoroethylene and its A technique is widely known that includes a gas diffusion layer on which a microporous layer composed of polytetrafluoroethylene and carbon powder is laminated. However, polytetrafluoroethylene is excellent in chemical stability and water repellency, but has low affinity with other substances, so when environmental changes where membrane electrode assemblies are placed, such as start / stop and storage environment, overlap, There has been a problem that the gas diffusion layer is peeled off and the performance of the fuel cell is lowered. In particular, when the softening point as in the non-perfluoropolymer electrode electrolyte is close to the decomposition temperature, there is a problem that the temperature during thermocompression bonding cannot be increased so that sufficient adhesion is obtained between the catalyst layer and the gas diffusion layer.

In order to solve such a problem, an attempt has been made to improve the bondability between the gas diffusion layer and the catalyst layer by providing an adhesive layer between the gas diffusion layer and the catalyst layer. For example, Patent Document 5 discloses an adhesive layer having a hydrogen ion conductive polymer electrolyte and conductive carbon. Patent Document 7 proposes an adhesive layer of a solvent-soluble perfluoropolymer having a low heat distortion temperature and carbon black.
JP 2007-26820 A JP 2007-13938 A JP 2003-331868 A JP 2004-149056 A Japanese Patent Laid-Open No. 2004-214045 JP 2004-259661 A

  However, when a resin having a high water content such as a proton conductive polymer electrolyte as in Patent Document 5 is used for the adhesive layer, the proton conductive polymer electrolyte swells including the power generation water, and the discharge of the power generation water is inhibited. There is a problem that the battery performance is lowered. Further, in Patent Document 6, although the thermal deformation temperature is lower, the bonding property by thermocompression bonding is improved than that of polytetrafluoroethylene, but since it is a perfluoro resin, the adhesive property of the resin itself is low and sufficient bonding property is obtained. There was a problem that it was not possible.

  The present invention has been made in view of the above viewpoints, and suppresses the separation of the gas diffusion layer with respect to the start and stop of the fuel cell and the environmental change where the membrane electrode assembly is placed such as the storage environment, and has excellent durability. An object of the present invention is to provide a membrane electrode assembly for a stationary or portable fuel cell.

  As a result of intensive studies to achieve the above object, the present inventors have devised a fluororesin binder to be included in at least a layer of the gas diffusion layer in contact with the catalyst layer, so that the bonding property between the gas diffusion layer and the catalyst layer is improved. As a result, the present inventors have found that the output of the fuel cell can be improved as compared with the gas diffusion layer using only polytetrafluoroethylene.

That is, the constituent requirements of the present invention are as follows.
[1] In a membrane / electrode assembly including an ion exchange resin membrane, a catalyst layer, and a gas diffusion layer, the gas diffusion layer on the cathode side has the following structural units (a), (b), and (c) A membrane electrode assembly for a stationary or portable fuel cell comprising the hydroxyl group-containing fluoropolymer (A).

(A) A structural unit represented by the following formula (1).
(B) A structural unit represented by the following formula (2).
(C) A structural unit represented by the following formula (3).

[In the formula (1), R ¹ is a fluorine atom, a fluoroalkyl group or a group represented by —OR ² (R ²
Represents an alkyl group or a fluoroalkyl group)]

[In the formula (2), R ³ represents a hydrogen atom or a methyl group, R ⁴ represents an alkyl group, and a group represented by — (CH ₂ ) _x —OR ⁵ or —OCOR ⁵ (R ⁵ represents an alkyl group or a glycidyl group. , X represents a number of 0 or 1, and represents a carboxyl group or an alkoxycarbonyl group]

[In formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydroxyalkyl group, and v represents a number of 0 or 1]
[2] The gas diffusion layer comprises a microporous layer in contact with the electrode layer and a porous base material layer in contact with the microporous layer, and the microporous layer contains the fluoropolymer (A). Membrane electrode assembly for portable fuel cells.
[3] The stationary or portable fuel cell membrane electrode assembly according to [2], wherein the microporous layer and the porous base material layer contain the fluoropolymer (A).
[4] The stationary or portable fuel cell membrane electrode assembly according to [1] to [3], wherein the gas diffusion layer contains a fluoropolymer (B) having no hydroxyl group.
[5] The stationary or portable fuel cell membrane electrode assembly according to any one of claims 1 to 4, wherein the cathode-side and anode-side gas diffusion layers contain a hydroxyl group-containing fluoropolymer (A).
[6] The stationary or portable fuel cell membrane / electrode assembly according to [1] to [5], wherein the hydroxyl group-containing fluoropolymer (A) has a glass transition temperature of 30 ° C to 160 ° C.
[7] The stationary or portable fuel cell membrane electrode assembly according to [1] to [6], wherein the hydroxyl group-containing fluoropolymer (A) is insoluble in water.
[8] At least one of the catalyst layer on the anode side and the cathode side includes a structural unit represented by the following general formula (A) and a structural unit represented by the following general formula (B) The fixed or portable fuel cell membrane electrode assembly according to [1], which is a polyarylene having a sulfonic acid group.

(Wherein, Y is _{-CO -, - SO 2 -,} - SO -, - CONH -, - COO -, - (CF 2) l
- (l is an integer of 1 to _{10), - C (CF 3)} 2 - represents at least one structure selected from the group consisting of, Z is a direct bond _{or, - (CH 2) l -} ( l is an integer of 1 to 10), at least one structure selected from the group consisting of —C (CH ₃ ) ₂ —, —O—, and —S—, and Ar represents —SO ₃ H or — An aromatic group having a substituent represented by O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H is shown. p shows the integer of 1-12, m shows the integer of 0-10, n shows the integer of 0-10, k shows the integer of 1-4. )

(In the formula, A and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH.
-, - COO -, - ( CF 2) l - (l is an integer of 1 to _{10), - (CH 2) l} - (l is an integer of 1 to 10), - CR _'2 - ( R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, —O—, or —S—. B represents independently an oxygen atom or a sulfur atom, R ^{1 to} R ¹⁶ may be the same or different from each other, and a hydrogen atom, a fluorine atom, an alkyl group, part or all of which are halogenated It represents at least one atom or group selected from the group consisting of halogenated alkyl groups, allyl groups, aryl groups, nitro groups, and nitrile groups. s and t represent an integer of 0 to 4, and r represents 0 or an integer of 1 or more. )
[9] A stationary or portable fuel cell having the membrane electrode assembly of [1] to [8].
[10] A resin paste for a gas diffusion layer of a stationary or portable fuel cell, comprising a hydroxyl group-containing fluoropolymer (A) having the following structural units (a), (b) and (c).

(A) A structural unit represented by the following formula (1).
(B) A structural unit represented by the following formula (2).
(C) A structural unit represented by the following formula (3).

[In the formula (1), R ¹ is a fluorine atom, a fluoroalkyl group or a group represented by —OR ² (R ²
Represents an alkyl group or a fluoroalkyl group)]

[In the formula (2), R ³ represents a hydrogen atom or a methyl group, R ⁴ represents an alkyl group, and a group represented by — (CH ₂ ) _x —OR ⁵ or —OCOR ⁵ (R ⁵ represents an alkyl group or a glycidyl group. , X represents a number of 0 or 1, and represents a carboxyl group or an alkoxycarbonyl group]

[In formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydroxyalkyl group, and v represents a number of 0 or 1]

According to the present invention, the start and stop of the fuel cell and the change of the environment in which the membrane electrode assembly is placed such as the storage environment is suppressed, and the gas diffusion layer is prevented from being peeled off. It is possible to provide a stationary or portable fuel cell membrane electrode assembly having a high output with respect to a gas diffusion layer using.

Hereinafter, the membrane electrode assembly for a stationary or portable fuel cell, the stationary or portable fuel cell, and the resin paste for a gas diffusion layer of the stationary or portable fuel cell according to the present invention will be described in detail.
[Membrane electrode assembly]
The membrane electrode assembly of the present invention includes an ion exchange resin membrane, a catalyst layer, and a gas diffusion layer. Typically, a cathode electrode catalyst layer is provided on one side of the ion exchange resin membrane, and an anode electrode catalyst layer is provided on the other side. Further, the ion exchange of each catalyst layer on the cathode side and the anode side is performed. Gas diffusion layers are provided on the cathode side and the anode side in contact with the side opposite to the resin film. Hereinafter, each of the gas diffusion layer, the catalyst layer, and the ion exchange resin membrane will be described.
[Gas diffusion layer]
The gas diffusion layer is composed of a porous substrate or a laminated structure of a porous substrate and a microporous layer. When the gas diffusion layer is composed of a laminated structure of a porous substrate and a microporous layer, the microporous layer is provided in contact with the catalyst layer. The gas diffusion layer on the cathode side needs to contain the hydroxyl group-containing fluorine-containing polymer (A) in order to impart water repellency, and the gas diffusion layers on the cathode side and anode side must contain the hydroxyl group-containing fluorine-containing polymer (A ) Is preferably included. When the gas diffusion layer is composed of a laminated structure of a porous substrate and a microporous layer, either one of the microporous layer and the porous substrate or both of the layers contain the hydroxyl group-containing fluoropolymer (A). The microporous layer preferably contains a hydroxyl group-containing fluoropolymer (A).
(1) Microporous layer The microporous layer contains carbon powder and a hydroxyl group-containing fluoropolymer (A) as a water repellent. Moreover, in addition to these components, the fluoropolymer (B) which does not have a hydroxyl group can be included. The microporous layer is formed using a microporous layer forming paste in which carbon powder or the like is dispersed in a solvent.

In the microporous layer composition used in the present invention, the carbon powder and the water repellent agent are preferably present in a weight ratio of 30 to 95:70 to 5, and are present in a weight ratio of 50 to 90:50 to 10. Is more preferable. When the content of the carbon powder is less than 30% by weight, it is difficult to form fine pores in the microporous layer, and the reactants are not easily diffused. When the content of the carbon powder exceeds 90% by weight, the carbon powder may drop off, which is not preferable.

The coating amount of the microporous layer used in the present invention is usually 0.5 to 15 mg / cm ² and is 0
. It is preferable that it exists in 5-10 mg / cm < ² >. When the coating amount is less than the above range, it is influenced by the porous substrate, the smoothness of the microporous layer is not sufficient, and the effect of forming the microporous layer cannot be obtained. On the other hand, when the coating amount exceeds the above range, the permeability of hydrogen, which is a fuel, decreases on the anode side, and the permeability and drainage of air (oxygen) decrease on the cathode side, thereby generating power. May decrease. For the above reason, when the microporous layer is composed of a plurality of layers, it is preferable that the total coating amount of each layer is in the above range.
(1-1) Carbon powder Examples of the carbon powder include carbon powder, carbon fiber, fullerene, carbon nanotube, carbon nanofiber, and silicon carbide whisker whose surface is coated with a carbon film. These may be used alone or in combination of two or more.

The carbon powder is preferably carbon black such as oil furnace black, channel black, lamp black, thermal black, and acetylene black from the viewpoint of electron conductivity and specific surface area.

  Examples of the oil furnace black include “Vulcan XC-72”, “Vulcan P”, “Black Pearls 880”, “Black Pearls 1100”, “Black Pearls 1300”, “Black Pearls 2000”, and “Regal 400” manufactured by Cabot Corporation. “Ketjen Black EC” manufactured by Lion Corporation, “# 3150, # 3250” manufactured by Mitsubishi Chemical Corporation, and the like. Examples of the acetylene black include “DENKA BLACK” manufactured by Denki Kagaku Kogyo.

As the carbon fiber, rayon-based carbon fiber, PAN-based carbon fiber, lignin pover-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, and the like can be used. Among these, vapor-grown carbon fiber is preferable.
(1-2) Hydroxyl-containing fluoropolymer (A)
The hydroxyl group-containing fluoropolymer (A) comprises the following structural units (a), (b) and (c).

(A) A structural unit represented by the following formula (1).
(B) A structural unit represented by the following formula (2).
(C) A structural unit represented by the following formula (3).

[In the formula (1), R ¹ is a fluorine atom, a fluoroalkyl group or a group represented by —OR ² (R ²
Represents an alkyl group or a fluoroalkyl group)]

[In the formula (2), R ³ represents a hydrogen atom or a methyl group, R ⁴ represents an alkyl group, and a group represented by — (CH ₂ ) _x —OR ⁵ or —OCOR ⁵ (R ⁵ represents an alkyl group or a glycidyl group. , X represents a number of 0 or 1, and represents a carboxyl group or an alkoxycarbonyl group]

[In formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydroxyalkyl group, and v represents a number of 0 or 1]
(I) Structural unit (a)
In the above formula (1), examples of the fluoroalkyl group represented by R ¹ and R ² include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluorohexyl group, a perfluorocyclohexyl group, and the like. A C1-C6 fluoroalkyl group is mentioned. Examples of the alkyl group for R ² include a methyl group, an ethyl group, a propyl group,
C1-C6 alkyl groups, such as a butyl group, a hexyl group, a cyclohexyl group, are mentioned.

  The structural unit (a) can be introduced by using a fluorine-containing vinyl monomer as a polymerization component. Such a fluorine-containing vinyl monomer is not particularly limited as long as it is a compound having at least one polymerizable unsaturated double bond and at least one fluorine atom. Examples thereof include fluororefines such as tetrafluoroethylene, hexafluoropropylene and 3,3,3-trifluoropropylene; alkyl perfluorovinyl ethers or alkoxyalkyl perfluorovinyl ethers; perfluoro (methyl vinyl ether), perfluoro Perfluoro (alkyl vinyl ethers) such as (ethyl vinyl ether), perfluoro (propyl vinyl ether), perfluoro (butyl vinyl ether), perfluoro (isobutyl vinyl ether); perfluoro (alkoxyalkyl vinyl ether) such as perfluoro (propoxypropyl vinyl ether) ) A single species or a combination of two or more species.

  Among these, hexafluoropropylene and perfluoro (alkyl vinyl ether) or perfluoro (alkoxyalkyl vinyl ether) are more preferable, and it is more preferable to use these in combination.

  In addition, the content rate of a structural unit (a) is 20-70 mol% when the whole quantity of a hydroxyl-containing fluoropolymer is 100 mol%. This is because if the content is less than 20 mol%, sufficient water repellency cannot be imparted to the gas diffusion layer, and the battery performance deteriorates due to retention of water as a power generation product. This is because if the content exceeds 70 mol%, the solubility of the hydroxyl group-containing fluoropolymer in an organic solvent or the adhesion to a substrate may be lowered.

For these reasons, the content of the structural unit (a) is more preferably 25 to 65 mol%, and more preferably 30 to 60 mol%, based on the total amount of the hydroxyl group-containing fluoropolymer. Is more preferable.
(Ii) Structural unit (b)
In the formula (2), examples of the alkyl group represented by R ⁴ or R ⁵ include alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, propyl group, hexyl group, cyclohexyl group, and lauryl group. Examples of the group include a methoxycarbonyl group and an ethoxycarbonyl group.

The structural unit (b) can be introduced by using the above-mentioned vinyl monomer having a substituent as a polymerization component. Examples of such vinyl monomers include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n -Alkyl vinyl ethers or cycloalkyl vinyl ethers such as octyl vinyl ether, n-dodecyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether; allyl ethers such as ethyl allyl ether, butyl allyl ether; vinyl acetate, vinyl propionate, vinyl butyrate, pivalin Carboxylic acid vinyl ester such as vinyl acid vinyl, vinyl caproate, vinyl vinyl versatate, vinyl stearate Tellurium; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2- ( (Meth) acrylic acid esters such as n-propoxy) ethyl (meth) acrylate; (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and other unsaturated carboxylic acids, etc. The combination of is mentioned.

  In addition, the content rate of a structural unit (b) is 5-50 mol% when the whole quantity of a hydroxyl-containing fluoropolymer is 100 mol%. This is because if the content is less than 5 mol%, the solubility of the hydroxyl group-containing fluoropolymer in the organic solvent may be reduced. On the other hand, if the content exceeds 50 mol%, This is because sufficient water repellency cannot be imparted to the diffusion layer, and battery performance deteriorates due to retention of water as a power generation product.

For such reasons, the content of the structural unit (b) is more preferably 10 to 40 mol%, more preferably 10 to 35 mol%, based on the total amount of the hydroxyl group-containing fluoropolymer. Is more preferable.
(Iii) Structural unit (c)
In formula (3), the hydroxyalkyl group for R ⁷ is a 2-hydroxyethyl group,
Examples thereof include 2-hydroxypropyl group, 3-hydroxypropyl group, 4-hydroxybutyl group, 3-hydroxybutyl group, 5-hydroxypentyl group, and 6-hydroxyhexyl group.

  The structural unit (c) can be introduced by using a hydroxyl group-containing vinyl monomer as a polymerization component. Examples of such hydroxyl group-containing vinyl monomers include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 3-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether, Examples include hydroxyl group-containing vinyl ethers such as 6-hydroxyhexyl vinyl ether, hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether, 4-hydroxybutyl allyl ether, and glycerol monoallyl ether, allyl alcohol, and the like.

  Moreover, as a hydroxyl-containing vinyl monomer, in addition to the above, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, caprolactone (meth) acrylate, polypropylene Glycol (meth) acrylate or the like can be used.

  In addition, it is preferable that the content rate of a structural unit (c) shall be 10-60 mol% when the whole quantity of a hydroxyl-containing fluoropolymer is 100 mol%. The reason for this is that when the content is less than 10 mol%, sufficient hydrogen bonds are not formed between the hydroxyl group in the fluoropolymer and the hydrophilic functional group on the catalyst layer carbon, so the catalyst layer and the gas diffusion layer are not formed. This is because sufficient adhesion cannot be obtained. On the other hand, when the content exceeds 60 mol%, sufficient water repellency cannot be imparted to the gas diffusion layer, and the battery performance deteriorates due to retention of water as the power generation product.

For these reasons, the content of the structural unit (c) is more preferably 15 to 55 mol% with respect to the total amount of the hydroxyl group-containing fluoropolymer, and 15 to 50 mol%. Is more preferable.
(Iv) Structural unit (d) and structural unit (e)
The hydroxyl group-containing fluoropolymer preferably further comprises the following structural unit (d).

  (D) A structural unit represented by the following formula (4).

[In formula (4), R ⁸ and R ⁹ may be the same or different and each represents a hydrogen atom, an alkyl group, a halogenated alkyl group or an aryl group]
In the formula (4), the alkyl group of R ⁸ or R ^{9 is} an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group or a propyl group, and the halogenated alkyl group is a trifluoromethyl group or perfluoro group. C1-C4 fluoroalkyl groups, such as an ethyl group, a perfluoropropyl group, a perfluorobutyl group, etc., A phenyl group, a benzyl group, a naphthyl group etc. are each mentioned as an aryl group.

  The structural unit (d) can be introduced by using an azo group-containing polysiloxane compound having a polysiloxane segment represented by the formula (4). Examples of such azo group-containing polysiloxane compounds include compounds represented by the following formula (5).

[In the formula (5), R ^{10 to} R ¹³ may be the same or different and each represents a hydrogen atom, an alkyl group or a cyano group, and R ^{14 to} R ¹⁷ may be the same or different and represent a hydrogen atom. Alternatively, it represents an alkyl group, p and q are numbers 1 to 6, s and t are numbers 0 to 6, y is a number 1 to 200, and z is a number 1 to 20. ]
When the compound represented by the formula (5) is used, the structural unit (d) is included in the hydroxyl group-containing fluoropolymer as a part of the structural unit (e).

  (E) A structural unit represented by the following formula (6).

[In the formula (6), R ^{10 to} R ¹³ , R ^{14 to} R ¹⁷ , p, q, s, t, and y are the same as in the above formula (5). ]
In the formulas (5) and (6), examples of the alkyl group represented by R ^{10 to} R ¹³ include alkyl groups having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, a hexyl group, and a cyclohexyl group. Examples of the alkyl group of ^{14 to} R ¹⁷ include an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, and a propyl group.

  In the present invention, the azo group-containing polysiloxane compound represented by the above formula (5) is particularly preferably a compound represented by the following formula (7).

[In Formula (7), y and z are the same as the said Formula (5). ]
In addition, it is preferable that the content rate of a structural unit (d) shall be 0.1-10 mol% when the whole quantity of a hydroxyl-containing fluoropolymer is 100 mol%. The reason for this is that when the content is less than 0.1 mol%, the surface slipperiness of the cured coating film is lowered, and the scratch resistance of the coating film may be lowered. If the amount exceeds 10 mol%, the transparency of the hydroxyl group-containing fluoropolymer is inferior, and when used as a coating material, repelling and the like are likely to occur during coating.

For these reasons, the content of the structural unit (d) is more preferably 0.1 to 5 mol% with respect to the total amount of the hydroxyl group-containing fluoropolymer, More preferably, it is mol%. For the same reason, the content of the structural unit (e) is desirably determined so that the content of the structural unit (d) contained therein is in the above range.
(V) Molecular Weight The hydroxyl group-containing fluoropolymer preferably has a polystyrene-equivalent number average molecular weight of 5,000 to 500,000 measured by gel permeation chromatography using tetrahydrofuran as a solvent. The reason for this is that when the number average molecular weight is less than 5,000, the mechanical strength of the hydroxyl group-containing fluoropolymer is lowered, and the bondability between the microporous layer and the catalyst layer may be lowered. Is over 500,000, the viscosity of the hydroxyl group-containing fluoropolymer solution or the hydroxyl group-containing fluoropolymer-containing microporous layer paste becomes high, which may make impregnation or coating difficult.

For these reasons, the number average molecular weight in terms of polystyrene of the hydroxyl group-containing fluoropolymer is more preferably 10,000 to 300,000, and even more preferably 10,000 to 100,000.
(1-3) Other fluorine-containing polymer (B)
The microporous material may contain a fluorine-containing polymer (B) having no hydroxyl group in addition to the hydroxyl group-containing fluorine-containing polymer (A). The fluorine-containing polymer (B) having no hydroxyl group imparts water repellency to the porous substrate in the same manner as the hydroxyl group-containing fluorine-containing polymer (A). Specific examples of the fluorine-containing polymer (B) having no hydroxyl group include polytetrafluoroethylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride, alkoxy vinyl ether, silane coupling agent, silicone resin, wax, polyphosphazene. Perfluorocarbon polymers having an aliphatic ring structure in the molecule, copolymers of fluorine-containing olefins and hydrocarbon olefins, copolymers of fluorine-containing acrylates and acrylates and / or methacrylates, polyvinylidene fluoride, poly Chlorotrifluoroethylene, polyhexafluoropropylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafur Roechiren - ethylene copolymer, polyvinylidene fluoride - hexafluoropropane, or their copolymers. Among these, a fluororesin is preferable from the viewpoint of durability of water repellency and ease of handling in use, and polytetrafluoroethylene and a tetrafluoroethylene-hexafluoropropylene copolymer are more preferable.
(1-4) Microporous layer forming paste The microporous layer used in the present invention is formed using the following microporous layer forming paste.

  In the present invention, the total weight of the carbon powder and the water repellent in the paste is 3% by weight to 50% by weight, preferably 10% by weight to 40% by weight, and the use ratio of the solvent is 50% by weight to 97% by weight. % By weight, preferably 60% by weight to 90% by weight, and the proportion of the dispersant used as necessary is 0% by weight to 45% by weight, preferably 0% by weight to 20% by weight. . When the use ratio of the carbon powder is less than the above range, it is difficult to form micropores in the microporous layer, and the reactant is not easily diffused. If it is larger than the above range, the carbon powder may fall off. If the ratio of the water repellent used is less than the above range, the carbon powder may fall off, which is not preferable. In addition, the water repellency becomes insufficient and the diffusibility of water may decrease, resulting in a decrease in power generation characteristics.If the ratio is larger than the above range, it is difficult to form fine pores in the microporous layer, and the reactants may not diffuse. Sometimes it is not done easily. When the use ratio of the solvent is within the above range, the coating property at the time of forming the microporous layer is excellent. When the proportion of the dispersant used is in the above range, a microporous layer-forming paste having excellent fluidity and storage stability can be obtained.

The water repellent is preferably used in a state dissolved in an organic solvent or dispersed in water for ease of handling in use.
The solvent for the microporous layer forming paste used in the present invention is not particularly limited, but water, methanol, ethanol, n-propyl alcohol, 2-propanol, 2-methyl-2-propanol, 2-butanol, isobutyl alcohol, and the like. Alcohols such as furan, tetrahydrofuran, tetrahydropyran, 1,2-dimethoxyethane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, γ-butyrolactone; dimethyl sulfoxide, N-methylformamide, N, N- Examples include dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolodon. The said solvent may be used individually by 1 type, or may be used in combination of 2 or more type.

  If necessary, a dispersant may be further added to the microporous layer forming paste used in the present invention. Examples of such a dispersant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  Examples of the anionic surfactant include oleic acid / N-methyltaurine, potassium oleate / diethanolamine salt, alkyl ether sulfate / triethanolamine salt, polyoxyethylene alkyl ether sulfate / triethanolamine salt, special modified polyether Amine salt of ester acid, amine salt of higher fatty acid derivative, amine salt of special modified polyester acid, amine salt of high molecular weight polyether ester acid, amine salt of special modified phosphoric acid ester, high molecular weight polyester acid amide amine salt, special fatty acid derivative Amidoamine salt, alkylamine salt of higher fatty acid, amidoamine salt of high molecular weight polycarboxylic acid, sodium laurate, sodium stearate, sodium oleyl sulfate sodium salt, cetyl Sulfate sodium salt, stearyl sulfate sodium salt, oleyl sulfate sodium salt, lauryl ether sulfate, sodium alkylbenzene sulfonate, oil-soluble alkylbenzene sulfonate, α-olefin sulfonate, higher alcohol phosphate monoester disodium Salt, higher alcohol phosphoric acid diester disodium salt, zinc dialkyldithiophosphate and the like.

Examples of the cationic surfactant include benzyldimethyl {2- [2- (P-1
, 1,3,3-tetramethylbutylphenoxy) ethoxy] ethyl} ammonium chloride, octadecylamine acetate, tetradecylamine acetate, octadecyltrimethylammonium chloride, tallow trimethylammonium chloride, dodecyltrimethylammonium chloride, coconut trimethylammonium chloride Hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, palm dimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, dioleyldimethylammonium chloride, 1-hydroxyethyl-2-tallow imidazoline quaternary salt, 2-Heptadecenyl-hydroxyeth Imidazoline, stearamide ethyl diethylamine acetate, stearamide ethyl diethylamine hydrochloride, triethanolamine monostearate formate, alkyl pyridium salt, higher alkylamine ethylene oxide adduct, polyacrylamide amine salt, modified polyacrylamide amine salt, par And fluoroalkyl quaternary ammonium iodide.

  Examples of the amphoteric surfactant include dimethyl coconut betaine, dimethyl lauryl betaine, sodium laurylaminoethylglycine, sodium laurylaminopropionate, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, amide betaine, imidazolinium betaine, lecithin, 3 -[Ω-fluoroaccanoyl-N-ethylamino] -1-propanesulfonic acid sodium, N- [3- (perfluorooctanesulfonamido) propyl] -N, N-dimethyl-N-carboxymethyleneammonium betaine Can be mentioned.

  Examples of the nonionic surfactant include coconut fatty acid diethanolamide (1: 2 type), coconut fatty acid diethanolamide (1: 1 type), bovine fatty acid diethanolamide (1: 2 type), and bovine fatty acid diethanolamide (1). : 1 type), oleic acid diethanolamide (1: 1 type), hydroxyethyl lauryl amine, polyethylene glycol lauryl amine, polyethylene glycol palm amine, polyethylene glycol stearyl amine, polyethylene glycol beef tallow amine, polyethylene glycol beef tallow propylene diamine, polyethylene glycol di Oleylamine, dimethyllaurylamine oxide, dimethylstearylamine oxide, dihydroxyethyllaurylamine oxide, perfluoroalkylamine oxide, poly Vinylpyrrolidone, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, fatty acid ester of glycerin, fatty acid ester of pentaerythritol, fatty acid ester of sorbit, fatty acid ester of sorbitan And fatty acid esters of sugar.

The said dispersing agent may be used individually by 1 type, or may be used in combination of 2 or more type.
Of these, alkylphenol ethylene oxide adducts are preferred. When the above dispersant is added to the microporous layer-forming paste, the storage stability and fluidity are excellent, and the productivity during coating is improved.

The paste composition for forming a microporous layer used in the present invention can be prepared, for example, by mixing the above components at a predetermined ratio and kneading them by a conventionally known method. The order of mixing the components is not particularly limited. For example, all the components are mixed and stirred for a certain period of time, or components other than the dispersant are mixed and stirred for a certain period of time, and then the dispersant is added as necessary. It is preferable to add and to stir for a certain time. Moreover, you may adjust the quantity of an organic solvent as needed, and may adjust the viscosity of a composition.

(1-5) Formation method of microporous layer As a formation method of the microporous layer used by this invention, it forms by drying after apply | coating the said paste directly on a water-repellent agent coating porous base material or a catalyst layer. It is possible to form a microporous layer by applying a microporous layer forming paste on another transfer substrate and then transferring it to the water repellent coated porous substrate or catalyst layer by hot pressing. May be. Moreover, you may form by laminating | stacking the said microporous layer in several times.

Examples of the method for applying the microporous layer forming paste include brush coating, brush coating, bar coater coating, knife coater coating, doctor blade method, screen printing, and spray coating.
Removal of the solvent of the coating film formed on the substrate is performed by drying at a temperature of 30 ° C. to 200 ° C., preferably 40 ° C. to 180 ° C., for a time of 1 minute to 250 minutes, preferably 5 minutes to 120 minutes. Can do. Furthermore, the dispersant used as necessary can be removed by immersing in a solvent and extracting the dispersant as necessary. The solvent is selected from solvents that dissolve only the dispersant without dissolving the water repellent, and examples thereof include alcohols such as methanol, ethanol, 1-propanol, and 2-propanol. Further, the dispersant can be thermally decomposed and removed at a temperature lower than the decomposition and alteration temperature of the water repellent. The thermal decomposition is performed at a temperature of 200 ° C. to 400 ° C., preferably 250 ° C. to 380 ° C., for a time of 30 seconds to 250 minutes, preferably 10 minutes to 180 minutes. As the transfer substrate, a polytetrafluoroethylene (PTFE) sheet or a glass plate or a metal plate whose surface is treated with a release agent can be used.

The hot press conditions are as follows: temperature 30 ° C. to 200 ° C., preferably 40 ° C. to 180 ° C., pressure 5 to 300 kg / cm ² , preferably 10 to 120 kg / cm ² , time 30 seconds to 60 minutes, preferably 1 minute to 30 For minutes. Within the above range, the bonding property between the water repellent coated porous substrate or catalyst layer and the microporous layer is improved.
(1-6) Water-repellent treatment method for microporous layer The hydroxyl group-containing fluoropolymer (A) used in the present invention can be contained in a porous substrate or microporous layer as a water-repellent agent by the method described above. . Moreover, it can also contain by forming a gas diffusion layer using water repellents other than a hydroxyl-containing fluoropolymer, and adding a hydroxyl-containing fluoropolymer later. As a method to be added later, a solution in which a hydroxyl group-containing fluoropolymer is dissolved in a solvent containing an organic solvent or a solution in which a hydroxyl group-containing fluoropolymer is suspended in a solvent containing water is added to the gas diffusion layer. It can apply | coat and dry to the surface which contacts a catalyst layer, and can form a hydroxyl-containing fluoropolymer layer. Although it does not specifically limit as an organic solvent, A ketone type | system | group, an ether type | system | group, and an alcohol type are preferable. The application method is not particularly limited, and examples thereof include a doctor blade method, screen printing, and spray coating method. As an impregnation method, first, a solution in which a hydroxyl group-containing fluoropolymer is dissolved in an organic solvent is prepared. A porous substrate or a porous substrate having a microporous layer formed thereon is immersed in this solution for several minutes, and the organic solvent is dried and removed. Thereby, an adhesive fluororesin can be added. The organic solvent is not particularly limited as long as it dissolves the hydroxyl group-containing fluoropolymer and has a boiling point not higher than the decomposition temperature of the hydroxyl group-containing fluoropolymer. When the hydroxyl group-containing fluoropolymer is added later, the addition amount is 0.01 to 5 mg / cm ² , preferably 0.1 to 1 mg / cm ² . If it is below the above range, sufficient adhesion cannot be obtained, and if it is above the above range, the pores of the gas diffusion layer are blocked and the battery performance is deteriorated.
(2) Porous base material As the porous base material used in the present invention, a porous base material generally used for fuel cells, for example, a porous conductive sheet mainly composed of a conductive substance, is particularly limited. It can be used without being done.

  Examples of the conductive substance include a fired body from polyacrylonitrile, a fired body from pitch, carbon powders such as graphite and expanded graphite, stainless steel, molybdenum, and titanium. Although the form of the said conductive substance is not specifically limited, such as fibrous form or particle form, Preferably it is a fibrous conductive inorganic substance (inorganic conductive fiber), Most preferably, it is a carbon fiber.

  As a porous conductive sheet using inorganic conductive fibers, either a woven fabric or a non-woven fabric structure can be used. As the woven fabric, plain weaving, oblique weaving, satin weaving, crest weaving, binding weaving and the like can be used without any particular limitation. Moreover, as a nonwoven fabric, what was manufactured by methods, such as a papermaking method, a needle punch method, a spun bond method, a water jet punch method, a melt blow method, can be used without being specifically limited. The porous conductive sheet using inorganic conductive fibers may be a knitted fabric.

  In particular, when carbon fiber is used as such a fabric, a plain fabric using flame-resistant spun yarn is carbonized or graphitized, and the flame-resistant yarn is carbonized after being processed into a nonwoven fabric by a needle punch method or a water jet punch method. Or a graphitized nonwoven fabric, a flame-resistant yarn, a mat nonwoven fabric by a paper making method using carbonized yarn or graphitized yarn, and the like are preferable. For example, Toray carbon paper “TGP series”, “SO series”, carbon cloth manufactured by E-TEK, carbon paper and carbon felt manufactured by SGL, carbon paper manufactured by Mitsubishi Rayon, and the like are preferably used.

Further, a hydroxyl group-containing fluoropolymer (A) or a hydroxyl group-containing fluoropolymer (A) and a fluoropolymer (B) having no hydroxyl group can be added as a water repellent material to form a porous substrate. . In this case, the hydroxyl group-containing fluoropolymer (A) used for the porous substrate and the fluoropolymer (B) having no hydroxyl group are the same as those used for the microporous layer.
(2-1) Method for forming porous substrate The porous substrate is preferably formed by subjecting the conductive material to a water repellent treatment. A water-repellent treatment of a porous substrate is carried out by dispersing a hydroxyl group-containing fluoropolymer (A) or a hydroxyl group-containing fluoropolymer (A) and a fluoropolymer (B) having no hydroxyl group in water. John or a water repellent solution dissolved in an organic solvent (hereinafter also referred to as a water repellent treatment resin) is coated with a water repellent by the method described below, and the components other than the water repellent (solvent, dispersion) It can be prepared by drying and thermally decomposing the agent. As the water repellent coating method, a dip coating method, a screen printing method, a spray coating method or a coating method using a doctor blade, a gravure coating method, a silk screen method, a painting method, etc. are used depending on the viscosity of the composition. It is not limited to this. Among these, the dip coating method is preferable. In the case of the dip coating method, the coating amount of the water repellent resin can be adjusted by the concentration of the dispersion or the water repellent solution. The coating amount of the water repellent treatment resin on the porous substrate is preferably such that the weight ratio of the water repellent to the water repellent treated porous substrate is 1 wt% to 50 wt%, more preferably 2 wt%. -30% by weight, preferably 5-20% by weight.

It is preferable that the coating amount of the water-repellent treatment resin is within the above-mentioned range since CO ₂ is discharged at the anode and generated water is discharged at the cathode, which improves power generation characteristics.
Further, when the microporous layer forming paste is applied to the water-repellent treated porous substrate, the microporous layer forming paste is prevented from being clogged with the porous substrate by the penetration into the porous substrate, water, Since a gas diffusion path can be secured, power generation characteristics are improved, which is preferable.
[Catalyst layer]
The catalyst layer constituting the membrane electrode assembly can be formed using a catalyst paste. The catalyst paste contains a catalyst, an ion exchange resin electrolyte and a solvent, and preferably contains a carbon fiber, a resin having no ion exchanger, water, a dispersant, etc. in addition to the catalyst, the ion exchange resin electrolyte and the solvent. be able to.
(1) Catalyst As the catalyst, a noble metal catalyst such as platinum, palladium, gold, ruthenium or iridium is preferably used. The noble metal catalyst may contain two or more elements such as an alloy or a mixture.

  From the viewpoint of effectively using the catalyst, a catalyst in which the above catalyst is supported on carbon fine particles having a high specific surface area can be used. As the carbon support, carbon black such as oil furnace black, channel black, lamp black, thermal black, acetylene black and the like is preferable from the viewpoint of electron conductivity and specific surface area.

  Examples of the oil furnace black include “Vulcan XC-72”, “Vulcan P”, “Black Pearls 880”, “Black Pearls 1100”, “Black Pearls 1300”, “Black Pearls 2000”, and “Regal 400” manufactured by Cabot Corporation. “Ketjen Black EC” manufactured by Lion Corporation, “# 3150, # 3250” manufactured by Mitsubishi Chemical Corporation, and the like. Examples of the acetylene black include “DENKA BLACK” manufactured by Denki Kagaku Kogyo.

  Further, as the carbon, artificial graphite or carbon obtained from an organic compound such as natural graphite, pitch, coke, polyacrylonitrile, phenol resin, furan resin, or the like may be used.

As the form of the carbon material, a particulate form as well as a fibrous form can be used.
The amount of the catalyst supported on the carbon is not particularly limited as long as it is an amount that can effectively exhibit catalytic activity, but the catalyst content in the catalyst-supported carbon is 10 to 95% by weight. Desirably, it is more suitable in it being 20 to 85 weight%. If the catalyst content is higher than the above range, the number of catalysts that are not used effectively increases, resulting in an inefficient electrode. Further, when the catalyst content is smaller than the above, a sufficient amount of catalyst cannot be obtained, so that the battery performance is lowered.
(2) Ion exchange resin electrolyte The ion exchange resin electrolyte functions as a binder component for binding the carbon carrying the catalyst, and efficiently supplies ions generated by the reaction on the catalyst to the ion conductive membrane at the fuel electrode. In addition, the air electrode efficiently supplies ions supplied from the ion conductive membrane to the catalyst.

  The ion exchange resin for the catalyst layer used in the present invention is preferably a polymer having a proton exchange group in order to improve proton conductivity in the catalyst layer. Proton exchange groups contained in such polymers include sulfonic acid groups, carboxylic acid groups, and phosphoric acid groups, but are not particularly limited. A polymer having such a proton exchange group is also selected without any particular limitation, and a polymer having a proton exchange group composed of a fluoroalkyl ether side chain and a fluoroalkyl main chain, or a sulfonated polyarylene. Etc. are preferably used. In addition, a polyarylene polymer having a sulfonic acid group constituting the aromatic ion exchange resin membrane described above may be used as an ion exchange resin, and a polymer containing a fluorine atom having a proton exchange group, or ethylene Or other polymers obtained from styrene or the like, copolymers or blends thereof.

  As such an ion exchange resin electrolyte, known ones can be used without particular limitation, and for example, Nafion (DuPont, registered trademark), sulfonated polyarylene, etc. can be used without particular limitation.

Although the specific aspect of the sulfonated polyarylene that can be used in the present invention is not particularly limited, a preferable aspect will be described later.
(3) Carbon fiber Carbon fiber may be further added to the catalyst layer used in the present invention as necessary. As such carbon fibers, rayon-based carbon fibers, PAN-based carbon fibers, lignin pover-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, and the like can be used. Among these, vapor-grown carbon fibers Is preferred.

When such a carbon fiber is further added to the catalyst layer, the pore volume in the catalyst layer is increased, so that the diffusibility of fuel gas and oxygen gas is improved, and flooding due to the generated water can be improved. Performance is improved.
(4) Resin not having an ion exchange group For the catalyst layer used in the present invention, a resin not having an ion exchange group may be used as necessary. These resins are preferably resins with high water repellency. For example, fluorine-containing copolymers, silane coupling agents, silicone resins, waxes, polyphosphazenes and the like can be mentioned, and fluorine-containing copolymers are preferred.

Examples of the fluorinated copolymer include a vinylidene fluoride copolymer, a perfluorocarbon polymer having an aliphatic ring structure in the molecule, a copolymer of a fluorinated olefin and a hydrocarbon olefin, and a fluorinated acrylate. Examples thereof include a copolymer with acrylate or / and methacrylate. Use of these resins having no ion exchange group is preferable because the wet state in the catalyst layer can be appropriately maintained.
(5) Water You may add water further to the catalyst paste composition used by this invention as needed. By adding water, there is an effect of reducing heat generation when preparing the catalyst paste composition.
(6) Dispersant A dispersant may be further added to the catalyst paste composition used in the present invention as necessary. Examples of such a dispersant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  Examples of the anionic surfactant include oleic acid / N-methyltaurine, potassium oleate / diethanolamine salt, alkyl ether sulfate / triethanolamine salt, polyoxyethylene alkyl ether sulfate / triethanolamine salt, special modified polyether Amine salt of ester acid, amine salt of higher fatty acid derivative, amine salt of special modified polyester acid, amine salt of high molecular weight polyether ester acid, amine salt of special modified phosphoric acid ester, high molecular weight polyester acid amide amine salt, special fatty acid derivative Amidoamine salt, alkylamine salt of higher fatty acid, amidoamine salt of high molecular weight polycarboxylic acid, sodium laurate, sodium stearate, sodium oleyl sulfate sodium salt, cetyl Sulfate sodium salt, stearyl sulfate sodium salt, oleyl sulfate sodium salt, lauryl ether sulfate, sodium alkylbenzene sulfonate, oil-soluble alkylbenzene sulfonate, α-olefin sulfonate, higher alcohol phosphate monoester disodium Salt, higher alcohol phosphoric acid diester disodium salt, zinc dialkyldithiophosphate and the like.

Examples of the cationic surfactant include benzyldimethyl {2- [2- (P-1,1,3,3-tetramethylbutylphenoxy) ethoxy] ethyl} ammonium chloride, octadecylamine acetate, tetradecylamine. Acetate, octadecyltrimethylammonium chloride, tallow trimethylammonium chloride, dodecyltrimethylammonium chloride, coconut trimethylammonium chloride, hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, coconut dimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, octadecyldimethylbenzyl Ammonium chloride, dioleyldimethylammonium chloride, 1- Roxyethyl-2-tallow imidazoline quaternary salt, 2-heptadecenyl-hydroxyethyl imidazoline, stearamide ethyl diethylamine acetate, stearamide ethyl diethylamine hydrochloride, triethanolamine monostearate formate, alkyl pyridium salt, higher alkyl amine ethylene Examples thereof include oxide adducts, polyacrylamide amine salts, modified polyacrylamide amine salts, and perfluoroalkyl quaternary ammonium iodides.

  Examples of the amphoteric surfactant include dimethyl coconut betaine, dimethyl lauryl betaine, sodium laurylaminoethylglycine, sodium laurylaminopropionate, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, amide betaine, imidazolinium betaine, lecithin, 3 -[Ω-fluoroaccanoyl-N-ethylamino] -1-propanesulfonic acid sodium, N- [3- (perfluorooctanesulfonamido) propyl] -N, N-dimethyl-N-carboxymethyleneammonium betaine Can be mentioned.

  Examples of the nonionic surfactant include coconut fatty acid diethanolamide (1: 2 type), coconut fatty acid diethanolamide (1: 1 type), bovine fatty acid diethanolamide (1: 2 type), and bovine fatty acid diethanolamide (1). : 1 type), oleic acid diethanolamide (1: 1 type), hydroxyethyl lauryl amine, polyethylene glycol lauryl amine, polyethylene glycol palm amine, polyethylene glycol stearyl amine, polyethylene glycol beef tallow amine, polyethylene glycol beef tallow propylene diamine, polyethylene glycol di Oleylamine, dimethyllaurylamine oxide, dimethylstearylamine oxide, dihydroxyethyllaurylamine oxide, perfluoroalkylamine oxide, poly Vinylpyrrolidone, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, fatty acid ester of glycerin, fatty acid ester of pentaerythritol, fatty acid ester of sorbit, fatty acid ester of sorbitan And fatty acid esters of sugar.

The said dispersing agent may be used individually by 1 type, or may be used in combination of 2 or more type. Among these, a surfactant having a basic group is preferable, an anionic or cationic surfactant is more preferable, and a surfactant having a molecular weight of 5,000 to 30,000 is more preferable. When the above dispersant is added to the electrode paste composition, the storage stability and fluidity are excellent, and the productivity during coating is improved.
(7) Catalyst layer composition In the present invention, the proportion of carbon black on which the catalyst is supported is 25 to 85% by weight, preferably 40 to 70% by weight. The use ratio is 10% by weight to 60% by weight, preferably 15% by weight to 50% by weight, and the use ratio of the resin having no ion exchange group used as necessary is 0% by weight. % To 40% by weight, preferably 0% to 20% by weight, and the proportion of carbon fiber used as necessary is 0% to 40% by weight, preferably 0% to 30% by weight. %, And the proportion of the dispersant used as necessary is 0 to 10% by weight, preferably 0 to 5% by weight.
(8) Catalyst paste composition The catalyst paste is formed by dissolving or dispersing each component in the usage ratio shown in the section of the catalyst layer in an organic solvent. Although the organic solvent used for a catalyst paste is not specifically limited, The following organic solvents are mentioned. Moreover, it is more preferable to use water in combination with these organic solvents.

Examples of the organic solvent used in the present invention include methanol, ethanol, n-propyl alcohol, 2-propanol, 2-methyl-2-propanol, 2-butanol, isobutyl alcohol, n-butyl alcohol, and 2-methyl-1. -Propanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2,2-dimethyl 1-propanol, cyclohexanol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexa Nord, 4-methylcyclohexanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, furan, tetrahydrofuran, tetrahydropyrandioxane, 1,2-dimethoxyethane, butyl ether, phenyl ether, isopentyl ether, diethoxy Ethane, bis (2-methoxyethyl) ether, bis (2-ethoxyethyl) ether, cineol, benzylethyl ether, anisole, phenetole, acetal, acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone, 2-hexanone, 4-methyl-2-pentanone, 2-heptanone, 2,4-dimethyl-3-pentanone, 2-octanone, n-butyl acetate, isobutyl acetate, sec-butyl acetate, vinegar Pentyl, isopentyl acetate, 3-methoxybutyl acetate, methyl butyrate, ethyl butyrate, methyl lactate, ethyl lactate, butyl lactate, dimethyl sulfoxide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, N , N-dimethylacetamide, N-methylpyrrolidone and the like, and these can be used in combination of one or more.

The proportion of the organic solvent used in the catalyst paste is 50 to 98 parts by weight, preferably 60 to 90 parts by weight, more preferably 70 to 85 parts by weight, with the total amount of the catalyst paste being 100 parts by weight. Part. Moreover, the usage-amount of water is 0-95 mass parts, Preferably it is 5-80 mass parts, More preferably, it is 10-30 mass parts.
When the use ratio of the organic solvent is within the above range, the coating property during electrode formation is excellent.

If the ratio of water used exceeds zero and falls within the above range, the risk of heat generation and ignition during electrode paste preparation can be reduced.

(9) Preparation of catalyst paste composition The catalyst paste composition can be prepared, for example, by mixing the above-mentioned components at a predetermined ratio and kneading them by a conventionally known method. The order of mixing the components is not particularly limited. For example, all the components are mixed and stirred for a certain period of time, or components other than the dispersant are mixed and stirred for a certain period of time, and then the dispersant is added as necessary. It is preferable to add and to stir for a certain time. Moreover, you may adjust the quantity of an organic solvent as needed, and may adjust the viscosity of a composition.
(10) Formation of catalyst layer The catalyst layer of the membrane electrode assembly according to the present invention can be formed by directly applying the electrode paste composition onto an ion exchange resin film and drying it.

Examples of the electrode paste composition coating method include brush coating, brush coating, bar coater coating, knife coater coating, doctor blade method, screen printing, and spray coating.
Removal of the solvent of the coating film formed on the substrate is performed by drying at a temperature of 30 ° C. to 200 ° C., preferably 40 ° C. to 180 ° C., for a time of 1 minute to 250 minutes, preferably 5 minutes to 120 minutes. be able to.

Catalyst layer formed on the substrate, if the cathode side to which an oxidant is supplied, that the platinum catalyst content in the catalyst layer is 0.1mg / cm ² ~6.0mg / cm ² preferably, more preferably from ^{0.3mg / cm 2 ~2.0mg / cm 2} . If the anode side of the fuel is supplied, a platinum catalyst content in the catalyst layer is preferably from ^{0.1mg / cm 2 ~4.0mg / cm 2} , more preferably 0.2 mg / cm ² ~ 1.0 mg / cm ² .

If the amount of platinum catalyst contained in the catalyst layer is less than the above range, the protonation reaction amount of hydrogen as a fuel on both the cathode side and the anode side decreases, and the power generation performance decreases. If the amount of platinum catalyst contained in the catalyst layer is more than the above range, the amount of platinum catalyst that is not used in the reaction increases, but if it is the anode side, the permeability of hydrogen as a fuel is reduced, and if it is the cathode side Air (oxygen) permeability and drainage may be reduced, and power generation performance may be reduced.

[Ion exchange resin membrane]
The ion exchange resin membrane used in the present invention is preferably a polymer having a proton exchange group in order to improve proton conductivity. Proton exchange groups contained in such polymers include sulfonic acid groups, carboxylic acid groups, and phosphoric acid groups, but are not particularly limited. A polymer having such a proton exchange group is also selected without any particular limitation, but sulfonated polyarylene is preferably used from the viewpoint of proton conductivity and gas permeation suppression. For example, the ion exchange resin membranes shown in Patent Document 3 and Patent Document 4 are suitable.

[Formation of membrane electrode assembly]
The membrane-electrode assembly according to the present invention is a method of joining the ion exchange resin membrane on which the catalyst layer is formed and a porous substrate by hot pressing or the like, and a porous substrate on which the catalyst layer is formed and ion exchange. The resin film is manufactured by a method of bonding by hot pressing or the like so that the catalyst layer side is in contact with the ion exchange resin film.

The conditions of the hot press are as follows: temperature is 50 ° C. to 200 ° C., preferably 80 ° C. to 180 ° C., pressure is 5 to 200 kg / cm ² , preferably 10 to 100 kg / cm ² , and time is 10 seconds to 60 minutes, preferably 1 to 30 minutes. By performing hot pressing under conditions within the above range, the bondability between the electrode layer and the film is improved.

Although the specific aspect of the sulfonated polyarylene that can be used in the present invention is not particularly limited, a preferable aspect will be described later.
[Adhesive layer]
In the stationary or portable fuel cell membrane electrode assembly of the present invention, an adhesive layer can be provided between the gas diffusion layer and the catalyst layer. By providing the adhesive layer, the bondability between the gas diffusion layer and the catalyst layer can be improved. In the case where the hydroxyl group-containing fluoropolymer (A) is contained only in the cathode-side gas diffusion layer and not in the anode-side gas diffusion layer, the adhesive layer is formed between the anode-side gas diffusion layer and the catalyst layer. It is particularly effective for improving adhesion.

The adhesive layer may have a known configuration such as an adhesive layer having a hydrogen ion conductive polymer electrolyte and conductive carbon, or an adhesive layer of a solvent-soluble perfluoropolymer having a low thermal deformation temperature and carbon black.
[Sulfonated polyarylene]
As the ion exchange resin, a protonic acid group-containing aromatic polymer can be used from the viewpoint of improving heat resistance and mechanical strength. Preferably, the structural unit represented by the following general formula (A) and the following general formula ( It is a polyarylene having a sulfonic acid group represented by the following general formula (C) including the structural unit represented by B). Such an ion exchange resin can also be used as an aromatic ion exchange resin membrane sandwiched between electrodes.
<Sulphonic acid unit>

In the general formula (A), Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —CO.
It represents at least one structure selected from the group consisting of O—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), and —C (CF ₃ ) ₂ —. Among, -CO -, - SO ₂ - is preferred.

Z is a direct bond or at least one selected from the group consisting of — (CH ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —C (CH ₃ ) ₂ —, —O—, and —S—. The structure of the species is shown. Among these, a direct bond and -O- are preferable.

Ar is an aromatic group having a substituent represented by —SO ₃ H or —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H (p represents an integer of 1 to 12). Indicates.
Specific examples of the aromatic group include a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Of these groups, a phenyl group and a naphthyl group are preferable. -SO ₃
At least one substituent represented by H or —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H (p represents an integer of 1 to 12) is substituted. In the case of a naphthyl group, it is preferable that two or more are substituted.

m is an integer of 0 to 10, preferably 0 to 2, n is an integer of 0 to 10, preferably 0 to 2, and k is an integer of 1 to 4.
As a preferable combination of the values of m and n and the structures of Y, Z and Ar,
(1) a structure in which m = 0, n = 0, Y is —CO—, and Ar is a phenyl group having —SO ₃ H as a substituent;
(2) a structure in which m = 1, n = 0, Y is —CO—, Z is —O—, and Ar is a phenyl group having —SO ₃ H as a substituent;
(3) a structure in which m = 1, n = 1, k = 1, Y is —CO—, Z is —O—, and Ar is a phenyl group having —SO ₃ H as a substituent;
(4) a m = 1, n = 0, Y is -CO-, 2 pieces of -SO ₃ as Ar is a substituted group
A structure which is a naphthyl group having H,
(5) m = 1, n = 0, Y is —CO—, Z is —O—, and Ar is a phenyl group having —O (CH ₂ ) ₄ SO ₃ H as a substituent. Examples include structures.
<Hydrophobic unit>

In the general formula (B), A and D are independently a direct bond or —CO—, —SO ₂ —, —S.
O -, - CONH -, - COO -, - (CF 2) l - (l is an integer of 1 to _{10), - (CH 2) l} - (l is an integer of 1 to 10), - CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, —O—, and —S—. And at least one structure. Here, specific examples of the structure represented by —CR ′ ₂ — include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, propyl group, octyl group, decyl group. Group, octadecyl group, phenyl group, trifluoromethyl group, and the like.

Among these, a direct bond, —CO—, —SO ₂ —, —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group), cyclohexylidene Group, fluorenylidene group and -O- are preferred.

B is independently an oxygen atom or a sulfur atom, preferably an oxygen atom.
R ^{1 to} R ¹⁶ may be the same as or different from each other, and are a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group in which a part or all of them are halogenated, an allyl group, an aryl group, a nitro group, a nitrile group. At least one atom or group selected from the group consisting of

  Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group, a cyclohexyl group, and an octyl group. Examples of the halogenated alkyl group include a trifluoromethyl group, a pentafluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group. Examples of the allyl group include a propenyl group, and examples of the aryl group include a phenyl group and a pentafluorophenyl group.

s and t represent an integer of 0 to 4. r shows 0 or an integer greater than or equal to 1, and an upper limit is 100 normally, Preferably it is 1-80.
Preferred combinations of the values of s and t and the structures of A, B, D, and R ^{1 to} R ¹⁶ include (1) s = 1, t = 1, and A is —CR ′ ₂ — (R ′ Represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, B is an oxygen atom, D is —CO— or —SO ₂ —. Wherein R ^{1 to} R ¹⁶ are hydrogen atoms or fluorine atoms, (2) s = 1, t = 0, B is an oxygen atom, D is —CO— or —SO ₂ —. A structure in which R ^{1 to} R ¹⁶ are a hydrogen atom or a fluorine atom, (3) s = 0, t = 1, and A is —CR ′ ₂ — (R ′ is an aliphatic hydrocarbon group, aromatic carbonization. Hydrogen group and halogenated hydrocarbon group), cyclohexylidene group, fluorenylidene group, B is an oxygen atom , R ^{1 to} R ¹⁶ are a hydrogen atom, a fluorine atom, or a nitrile group.
<Polymer structure>

In the general formula (C), A, B, D, Y, Z, Ar, k, m, n, r, s, t, and R ^{1 to} R ¹⁶ are respectively in the general formulas (A) and (B). A, B, D, Y, Z, Ar, k
, M, n, r, s, t, and R ^{1 to} R ¹⁶ . x and y represent molar ratios when x + y = 100 mol%.

In the polyarylene having a sulfonic acid group used in the present invention, the structural unit represented by the formula (A), that is, the unit of x is 0.5 to 100 mol%, preferably 10 to 99.999 mol%, The structural unit represented by the formula (B), that is, the y unit is contained in a ratio of 99.5 to 0 mol%, preferably 90 to 0.001 mol%.
<Method for producing polymer>
For the production of the polyarylene having a sulfonic acid group, for example, the following three methods, Method A, Method B and Method C, can be used.

  (Method A) For example, in the method described in JP-A No. 2004-137444, a monomer having a sulfonate group that can be a structural unit represented by the above general formula (A) and the above general formula (B) To produce a polyarylene having a sulfonic acid ester group by copolymerizing with a monomer or oligomer that can be a structural unit, and deesterifying the sulfonic acid ester group to convert the sulfonic acid ester group into a sulfonic acid group Can be synthesized.

  (Method B) For example, in the method described in JP-A No. 2001-342241, a monomer having a skeleton represented by the general formula (A) and having no sulfonic acid group or sulfonic acid ester group, and the general formula (B It is also possible to synthesize the polymer by copolymerizing with a monomer or oligomer that can be a structural unit represented by formula (I) and sulfonating the polymer using a sulfonating agent.

(Method C) In the general formula (A), Ar is —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p
In the case of an aromatic group having a substituent represented by SO ₃ H, for example, JP-A-2005-6
The precursor monomer that can be the structural unit represented by the general formula (A) and the monomer or oligomer that can be the structural unit represented by the general formula (B) by the method described in Japanese Patent No. 0625. It can also be synthesized by polymerizing and then introducing an alkyl sulfonic acid or a fluorine-substituted alkyl sulfonic acid.

  Specific examples of the monomer having a sulfonate group that can be used in (Method A) and can be the structural unit represented by the above general formula (A) are disclosed in JP-A Nos. 2004-137444 and 2004-2004. Examples thereof include sulfonic acid esters described in Japanese Patent Nos. 3459997 and 2004-346163.

  As specific examples of the monomer having no sulfonic acid group or sulfonic acid ester group that can be a structural unit represented by the above general formula (A) that can be used in (Method B), JP-A-2001-342241, Examples thereof include dihalides described in JP-A-2002-29389.

  Specific examples of precursor monomers that can be used in (Method C) and can be structural units represented by the above general formula (A) include dihalides described in JP-A-2005-36125. Can be mentioned.

In addition, as a specific example of a monomer or oligomer that can be a structural unit represented by the general formula (B) used in any method,
When r = 0, for example, 4,4′-dichlorobenzophenone, 4,4′-dichlorobenzanilide, 2,2-bis (4-chlorophenyl) difluoromethane, 2,2-bis (4-chlorophenyl) -1, 1,1,3,3,3-hexafluoropropane, 4-chlorobenzoic acid-4-chlorophenyl ester, bis (4-chlorophenyl) sulfoxide, bis (4-chlorophenyl) sulfone, 2,6-dichlorobenzonitrile It is done. In these compounds, a compound in which a chlorine atom is replaced with a bromine atom or an iodine atom is exemplified.

In the case of r = 1, for example, compounds described in JP-A-2003-113136 can be exemplified.
In the case of r ≧ 2, for example, JP 2004-137444 A, JP 2004-244517 A, JP 2004-346146 A, JP 2005-112985 A, Japanese Patent Application 2003-348524, and Japanese Patent Application 2004-211739. And compounds described in Japanese Patent Application No. 2004- 211740.

  In order to obtain a polyarylene having a sulfonic acid group, first, a monomer that can be a structural unit represented by the general formula (A) and a monomer that can be a structural unit represented by the general formula (B), Alternatively, it is necessary to copolymerize with an oligomer to obtain a precursor polyarylene. This copolymerization is carried out in the presence of a catalyst, and the catalyst used in this case is a catalyst system containing a transition metal compound. This catalyst system is (1) a transition metal salt and a ligand. A compound (hereinafter referred to as “ligand component”) or a transition metal complex coordinated with a ligand (including a copper salt) and (2) a reducing agent as essential components, and further increase the polymerization rate. Therefore, “salt” may be added.

  Specific examples of these catalyst components, the use ratio of each component, the polymerization conditions such as the reaction solvent, concentration, temperature, time, etc. include the compounds described in JP-A No. 2001-342241.

The polyarylene having a sulfonic acid group can be obtained by converting the precursor polyarylene into a polyarylene having a sulfonic acid group. As this method, there are the following three methods.
(Method A) A method of deesterifying a polyarylene having a sulfonic acid ester group as a precursor by the method described in JP-A-2004-137444.
(Method B) A method of sulfonating a precursor polyarylene by the method described in JP-A-2001-342241.
(Method C) A method of introducing an alkylsulfonic acid group into the precursor polyarylene by the method described in JP-A-2005-60625.

  The polyarylene having a sulfonic acid group of the general formula (C) produced by the above method has an ion exchange capacity of usually 0.3 to 5 meq / g, preferably 0.5 to 3 meq / g, more preferably Is 0.8 to 2.8 meq / g. If it is less than 0.3 meq / g, the proton conductivity is low and the power generation performance is low. On the other hand, if it exceeds 5 meq / g, the water resistance may be significantly lowered.

  The ion exchange capacity is, for example, a precursor monomer that can be a structural unit represented by the general formula (A), a monomer that can be a structural unit represented by the general formula (B), or the kind of oligomer, and the use ratio. It can be adjusted by changing the combination.

The molecular weight of the polyarylene having a sulfonic acid group thus obtained is 10,000 to 1,000,000, preferably 20,000 to 800,000 in terms of polystyrene-equivalent weight average molecular weight by gel permeation chromatography (GPC).

[Stationary or portable fuel cell]
The stationary or portable fuel cell of the present invention includes at least one electricity generation unit including at least one membrane-electrode assembly and separators located on both sides thereof; a fuel supply unit that supplies fuel to the electricity generation unit; And an oxidant supply unit that supplies the oxidant to the electricity generation unit, wherein the membrane-electrode assembly is as described above.

  As the separator used in the battery of the present invention, those used in ordinary fuel cells can be used. Specifically, carbon type or metal type can be used.

  Moreover, as a member which comprises a fuel cell, it is possible to use a well-known thing without a restriction | limiting in particular. The battery of the present invention can be used as a single cell or as a stack in which a plurality of single cells are connected in series. As a stacking method, a known method can be used. Specifically, planar stacking in which single cells are arranged in a plane and bipolar stacking in which single cells are stacked via separators each having a fuel or oxidant flow path formed on the back surface of the separator can be used. .

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.
[Synthesis Example 1: Synthesis of hydroxyl-containing fluoropolymer (a)]
A 2.0-liter stainless steel autoclave with a magnetic stirrer was sufficiently replaced with nitrogen gas, and then 400 g of ethyl acetate, 60.3 g of perfluoro (propyl vinyl ether), 27.2 g of ethyl vinyl ether, 33.2 g of hydroxyethyl vinyl ether, Lauroyl oxide 1.00 g, azo group-containing polydimethylsiloxane represented by the above formula (7) (VPS1001 (trade name), Wako Pure Chemical Industries, Ltd.) 1.7 g and nonionic reactive emulsifier (NE-30) (Product name, manufactured by Asahi Denka Kogyo Co., Ltd.) 40.0 g was charged, cooled to −50 ° C. with dry ice-methanol, and then oxygen in the system was removed again with nitrogen gas.

Next, 79.3 g of hexafluoropropylene was charged and the temperature increase was started. The pressure when the temperature in the autoclave reached 60 ° C. was 5.3 × 10 ⁵ Pa. Then 70
The reaction was continued with stirring at 20 ° C. for 20 hours. When the pressure dropped to 1.7 × 10 ⁵ Pa, the autoclave was cooled with water to stop the reaction. After reaching room temperature, unreacted monomers were released and the autoclave was opened to obtain a polymer solution having a solid content concentration of 26.4%. The obtained polymer solution was put into methanol to precipitate a polymer, washed with methanol, and vacuum dried at 50 ° C. to obtain 220 g of a hydroxyl group-containing fluoropolymer. This is referred to as a hydroxyl group-containing fluoropolymer.

The obtained hydroxyl group-containing fluoropolymer had a polystyrene-reduced number average molecular weight of 70000 by gel permeation chromatography and a glass transition temperature of 30 ° C. by DSC measurement. The hydroxyl group concentration based on the charging ratio of the monomer was 1.56 mol / g.

  VPS1001 is an azo group-containing polydimethylsiloxane represented by the above formula (7) having a number average molecular weight of 70 to 90,000 and a polysiloxane moiety having a molecular weight of about 10,000. NE-30 is a nonionic reactive emulsifier wherein n is 9, m is 1 and u is 30 in the above formula (10).

Furthermore, in Table 1, the correspondence between the monomer and the structural unit is as follows.
Monomer Structural unit Hexafluoropropylene (a)
Perfluoro (propyl vinyl ether) (a)
Ethyl vinyl ether (b)
Hydroxyethyl vinyl ether (c)
NE-30 (f)
Polydimethylsiloxane skeleton (d)
[Synthesis Example 2: Synthesis of hydroxyl group-containing fluoropolymer (b)]
A 2.0-liter stainless steel autoclave with a magnetic stirrer was sufficiently replaced with nitrogen gas, and then 400 g of ethyl acetate, 77.2 g of perfluoro (propyl vinyl ether), 58.5 g of ethyl vinyl ether, 25.8 g of hydroxyethyl vinyl ether, Lauroyl oxide 1.00 g, azo group-containing polydimethylsiloxane represented by the above formula (7) (VPS1001 (trade name), manufactured by Wako Pure Chemical Industries, Ltd.) 7.8 g and nonionic reactive emulsifier (NE-30) (Product name, manufactured by Asahi Denka Kogyo Co., Ltd.) 52.1 g was charged, cooled to −50 ° C. with dry ice-methanol, and then oxygen in the system was removed again with nitrogen gas.

Next, 98.9 g of hexafluoropropylene was charged, and the temperature increase was started. The pressure when the temperature in the autoclave reached 60 ° C. was 5.3 × 10 ⁵ Pa. Then 70
The reaction was continued with stirring at 20 ° C. for 20 hours. When the pressure dropped to 1.7 × 10 ⁵ Pa, the autoclave was cooled with water to stop the reaction. After reaching room temperature, unreacted monomers were released and the autoclave was opened to obtain a polymer solution having a solid content concentration of 26.4%. The obtained polymer solution was put into methanol to precipitate a polymer, washed with methanol, and vacuum dried at 50 ° C. to obtain 220 g of a hydroxyl group-containing fluoropolymer. This is referred to as a hydroxyl group-containing fluoropolymer.

The obtained hydroxyl group-containing fluoropolymer had a polystyrene-reduced weight average molecular weight of 70000 by gel permeation chromatography and a glass transition temperature of 32 ° C. by DSC measurement.
Met. The hydroxyl group concentration based on the charging ratio of the monomer was 0.93 mol / g.

  VPS1001 is an azo group-containing polydimethylsiloxane represented by the above formula (7) having a number average molecular weight of 70 to 90,000 and a polysiloxane moiety having a molecular weight of about 10,000. NE-30 is a nonionic reactive emulsifier wherein n is 9, m is 1 and u is 30 in the above formula (10).

Furthermore, in Table 1, the correspondence between the monomer and the structural unit is as follows.
Monomer Structural unit Hexafluoropropylene (a)
Perfluoro (propyl vinyl ether) (a)
Ethyl vinyl ether (b)
Hydroxyethyl vinyl ether (c)
NE-30 (f)
Polydimethylsiloxane skeleton (d)
[Comparative Synthesis Example 1: Synthesis of fluoropolymer (C) containing no hydroxyl group]
A stainless steel autoclave with an internal volume of 2.0 liters equipped with a magnetic stirrer was sufficiently replaced with nitrogen gas, and then 400 g of ethyl acetate, 77.2 g of perfluoro (propyl vinyl ether), 83.6 g of ethyl vinyl ether, 1.00 g of lauroyl peroxide, the above 2.2 g of azo group-containing polydimethylsiloxane represented by formula (7) (VPS1001 (trade name), manufactured by Wako Pure Chemical Industries, Ltd.) and nonionic reactive emulsifier (NE-30 (trade name), Asahi Denka) 52.2 g (manufactured by Kogyo Co., Ltd.) was charged, cooled to −50 ° C. with dry ice-methanol, and oxygen in the system was removed again with nitrogen gas.

Next, 98.9 g of hexafluoropropylene was charged, and the temperature increase was started. The pressure when the temperature in the autoclave reached 60 ° C. was 5.3 × 10 ⁵ Pa. Then 70
The reaction was continued with stirring at 20 ° C. for 20 hours. When the pressure dropped to 1.7 × 10 ⁵ Pa, the autoclave was cooled with water to stop the reaction. After reaching room temperature, unreacted monomers were released and the autoclave was opened to obtain a polymer solution having a solid content concentration of 26.4%. The obtained polymer solution was put into methanol to precipitate a polymer, washed with methanol, and vacuum dried at 50 ° C. to obtain 220 g of a hydroxyl group-containing fluoropolymer. This is referred to as a hydroxyl group-containing fluoropolymer.

The obtained hydroxyl group-containing fluoropolymer had a polystyrene-reduced number average molecular weight of 80,000 by gel permeation chromatography and a glass transition temperature of 33 ° C. by DSC measurement. Moreover, the hydroxyl group concentration from the charging ratio to the monomer was 0 mol / g.

  VPS1001 is an azo group-containing polydimethylsiloxane represented by the above formula (7) having a number average molecular weight of 70 to 90,000 and a polysiloxane moiety having a molecular weight of about 10,000. NE-30 is a nonionic reactive emulsifier wherein n is 9, m is 1 and u is 30 in the above formula (10).

Furthermore, in Table 1, the correspondence between the monomer and the structural unit is as follows.
Monomer Structural unit Hexafluoropropylene (a)
Perfluoro (propyl vinyl ether) (a)
Ethyl vinyl ether (b)
Hydroxyethyl vinyl ether (c)
NE-30 (f)
Polydimethylsiloxane skeleton (d)
(Production of ion exchange resin)
[Synthesis Example 3: Synthesis of ion exchange resin (d)]
(1) Synthesis of hydrophobic unit Into a 1 L three-necked flask equipped with a stirrer, thermometer, Dean-stark tube, nitrogen introduction tube, and cooling tube, 29.8 g (104 mmol) of 4,4′-dichlorodiphenylsulfone, 2, 27.4 g (111 mmol) of 2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane and 20.0 g (145 mmol) of potassium carbonate were weighed. After nitrogen substitution, 168 mL of sulfolane and 84 mL of toluene were added and stirred. The reaction solution was heated to reflux at 150 ° C. in an oil bath. Water produced by the reaction was trapped in a Dean-stark tube. After 3 hours, when almost no water was observed, toluene was removed from the Dean-stark tube out of the system. The reaction temperature was gradually raised to 200 ° C. and stirring was continued for 5 hours. Then, 7.5 g (30 mmol) of 4,4′-dichlorobenzophenone was added, and the reaction was further continued for 8 hours.

  The reaction solution was allowed to cool, and diluted with 100 mL of toluene. Inorganic salts insoluble in the reaction solution were filtered, and the filtrate was poured into 2 L of methanol to precipitate the product. The precipitated product was filtered and dried, then dissolved in 250 mL of tetrahydrofuran, and poured into 2 L of methanol for reprecipitation. The precipitated white powder was filtered and dried to obtain 56 g of a hydrophobic unit. The number average molecular weight (Mn) measured by GPC was 10,500. The obtained compound was confirmed to be an oligomer represented by the formula (I).

(2) Synthesis of Sulfonated Polyarylene 135.5 g (338 mmol) of neopentyl 3- (2,5-dichlorobenzoyl) benzenesulfonate was added to a 1 L three-necked flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube, (1) 44.5 g (4.2 mmol) of hydrophobic unit of Mn 10,500 obtained in the above, 6.71 g (10.3 mmol) of bis (triphenylphosphine) nickel dichloride, 1.54 g (10.3 mmol) of sodium iodide, 35.9 g (136 mmol) of phenylphosphine and 53.7 g (820 mmol) of zinc were weighed and replaced with dry nitrogen. 430 mL of N, N-dimethylacetamide (DMAc) was added thereto, and stirring was continued for 3 hours while maintaining the reaction temperature at 80 ° C. Then, 730 mL of DMAc was added for dilution, and insoluble matters were filtered off.

  The obtained solution was put into a 2 L three-necked flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, heated and stirred at 115 ° C., and 44 g (506 mmol) of lithium bromide was added. After stirring for 7 hours, the product was precipitated by pouring into 5 L of acetone. Next, after washing in order of 1N hydrochloric acid and pure water, it was dried to obtain 124 g of the desired sulfonated polymer. The weight average molecular weight (Mw) of the obtained polymer was 170,000. The obtained polymer is presumed to be a sulfonated polymer represented by the formula (II). The ion exchange capacity of this polymer was 2.3 meq / g. The ion exchange capacity is determined by preparing a membrane made of an ion exchange resin, weighing a predetermined amount, and using phenolphthalein dissolved in a THF / water mixed solvent as an indicator, titrating with a standard solution of NaOH, and neutralizing point. Was used to determine the ion exchange capacity.

(3) Production of ion exchange resin membrane A 10% by weight N-methylpyrrolidone (NMP) solution of polyarylene having a sulfonic acid group is cast on a glass plate to form a film, and the ion exchange resin membrane has a thickness of 30 μm. Got.
(4) Measurement of molecular weight The molecular weight of the polyarylene having no sulfonic acid group was determined by GPC using polystyrene as the solvent and the molecular weight in terms of polystyrene was obtained. The molecular weight of the polyarylene having a sulfonic acid group was determined in terms of polystyrene by GPC using N-methyl-2-pyrrolidone to which lithium bromide and phosphoric acid were added as an eluent.
[Evaluation of power generation and adhesion]
A catalyst-coated ion exchange resin membrane, which will be described later, is sandwiched between two gas diffusion layers, which will be described later, so that the microporous layer and the catalyst layer are in contact with each other, and heated at 160 ° C. and 60 kgf / cm ² for 15 minutes. A membrane-electrode assembly was produced by pressure heating, and assembled into an evaluation fuel cell manufactured by Electrochem, and tightened with a torque wrench at 300 cN m to produce a fuel cell. Hydrogen was supplied to the anode so that the utilization rate was 70%, and air was supplied to the cathode so that the utilization rate was 40%. The anode and cathode feed gases were humidified at 100% relative humidity. The initial performance of the fuel cell was evaluated by measuring the output when the power was generated at 0.75 V at a battery temperature of 70 ° C. Thereafter, a resistance test was performed three times by leaving the fuel cell at −10 ° C. for 24 hours, and the output was measured again under the above conditions to evaluate the performance after the resistance test. After the power generation test, the fuel cell for evaluation was disassembled and the peeling state of the gas diffusion layer was confirmed, ○ where no peeling was seen, x when the gas diffusion layer was dropped, no dropping occurred, A portion where peeling was observed was indicated as Δ.
[Example 1]
(Production of gas diffusion layer)
(1) Production of porous substrate Carbon paper (trade name: TGPH-060, manufactured by Toray Industries, Inc.) as a porous substrate is cut into a size of 5 cm × 5 cm, and this is 30 mL of 1.0 wt% hydroxyl group-containing material. Fluoropolymer (I) 1,
After being immersed in 2 dimethoxyethane solution for 5 minutes, it was dried in a 75 ° C. drying oven for 30 minutes. A hydroxyl group-containing fluoropolymer (I) coated porous substrate was produced. The adhesion amount of the hydroxyl group-containing fluoropolymer (A) at this time was 0.1 mg / cm ² .
(2) Formation of microporous layer 1.0 g of carbon particles (trade name: Ketjen Black EC, manufactured by Lion Corp.), 2.0 g of the hydroxyl group-containing fluoropolymer (I) described in Synthesis Example 1, 0.6 g of distilled water, 11.4 g of 1,2-dimethoxyethane was mixed, and this mixture was stirred using a planetary ball mill (trade name: P-5, manufactured by Fritsch) until uniform to prepare a microporous layer forming paste. . After applying this paste uniformly using an applicator so that the weight of the microporous layer is 1.5 mg / cm ² , the paste is dried for 30 minutes in a drying oven at 75 ° C. Polymer (A) coat-coated porous substrate was prepared.
(Catalyst paste composition)
Using commercially available 46% by weight platinum-supported carbon (trade name: TEC10E50E, manufactured by Tanaka Kikinzoku), 1.5 g of platinum-supported carbon, 2.4 g of a small amount of distilled water, 20% Nafion (registered trademark) solution 5 manufactured by DuPont 0.2 g and 10.2 g of isopropanol were mixed, and the mixture was stirred using a planetary ball mill (trade name: P-5, manufactured by Fritsch) until uniform to prepare a catalyst paste.
(Catalyst-coated ion exchange resin membrane production)
The catalyst paste is uniformly applied to one side of the ion exchange resin membrane using an applicator so that the amount of platinum deposited is 0.5 mg / cm ² , and then dried in a drying oven at 75 ° C. for 30 minutes. Then, an anode catalyst layer was formed. Use an applicator so that the amount of platinum deposited is 0.5 mg / cm ² on the surface of the ion exchange resin membrane on which the anode catalyst layer is formed, on the side opposite to the surface on which the anode catalyst layer is formed. After uniformly coating, it was dried in a drying furnace at 75 ° C. for 30 minutes to form a cathode catalyst layer, and a catalyst-coated ion exchange resin membrane was produced.
[Example 2]
(Production of gas diffusion layer)
(1) Production of porous substrate Carbon paper (trade name: TGPH-060, manufactured by Toray Industries, Inc.) as a porous substrate was cut into a size of 5 cm x 5 cm, and this was cut into 30 mL of 1.2 wt% polytetra After being immersed in the fluoroethylene resin fine particle dispersion aqueous solution for 5 minutes, it was dried in a drying furnace at 75 ° C. for 15 minutes. This substrate was baked in an electric furnace at 370 ° C. for 1 hour to produce a water repellent coated porous substrate for anode and cathode.
(2) Formation of microporous layer A water repellent coated porous substrate with a microporous layer was produced in the same manner as in Example 1.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Example 3]
(Production of gas diffusion layer)
(1) Production of porous substrate A water repellent-coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Carbon particles (trade name: Ketjen Black EC, manufactured by Lion Corporation) ) 2.4 g, 60 wt% polytetrafluoroethylene resin fine particle dispersion aqueous solution 6.2 g, distilled water 104.9 g, dispersant (trade name: TRITONX-100, manufactured by Sigma-Aldrich) 10.3 g The mixture was stirred using a planetary ball mill (trade name: P-5, manufactured by Fritsch) until uniform, to prepare a microporous layer forming paste for an anode. After applying this paste uniformly using an applicator so that the weight of the microporous layer is 1.0 mg / cm ² , the paste is dried in a drying furnace at 75 ° C. for 30 minutes to provide a water repellent coating with a microporous layer. A porous substrate was prepared.
(3) Hydroxyl-containing fluorine-containing polymer coat The above-mentioned water-repellent-coated porous substrate with a microporous layer is immersed in 30 mL of a 10 wt% hydroxyl-containing fluoropolymer (ii) 1,2 dimethoxyethane solution for 5 minutes. Then, it was dried for 30 minutes in a 75 ° C. drying oven. A hydroxyl group-containing fluoropolymer (I) coat gas diffusion layer was produced. The adhesion amount of the hydroxyl group-containing fluoropolymer (I) at this time was 1.0 mg / cm ² .
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Example 4]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Hydroxyl group-containing fluorinated polymer coat The above-mentioned water-repellent-coated porous substrate with a microporous layer was added to 30 mL of 0.1% by weight hydroxyl group-containing fluorinated polymer (ii) 1,2 dimethoxyethane solution for 5 minutes. After being immersed, it was dried in a drying furnace at 75 ° C. for 30 minutes. A hydroxyl group-containing fluoropolymer (I) coat gas diffusion layer was produced. The adhesion amount of the hydroxyl group-containing fluoropolymer (A) at this time was 0.01 mg / cm ² .
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Example 5]
(Production of gas diffusion layer)
(1) Production of porous substrate)
A water repellent coated porous substrate was prepared in the same manner as in Example 2 (2) Formation of a microporous layer A water repellent coated porous substrate with a microporous layer was prepared in the same manner as in Example 3. . This gas diffusion layer was used for the anode.
(3) Formation of adhesive layer 4.45 g of 20% Nafion (registered trademark) solution manufactured by DuPont, 7.02 g of normal propanol, 7.42 g of distilled water, and 1.11 g of ketjen black EC are mixed, and this mixture is made into a planetary ball mill until uniform. (Product name: P-5, manufactured by Fritsch) was used to stir to prepare an adhesive layer paste. The paste was applied onto a microporous layer of a water-repellent-coated porous substrate with a microporous layer with an applicator and then dried in a drying furnace at 75 ° C. for 30 minutes to produce a gas diffusion layer with an adhesive layer. The coating amount after drying of the adhesive layer was 2 mg / cm ² . This gas diffusion layer was used for the anode.
(4) Hydroxyl group-containing fluoropolymer coat A hydroxyl group-containing fluoropolymer (I) coat gas diffusion layer was produced in the same manner as in Example 4. This gas diffusion layer was used for the cathode.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Example 6]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Hydroxyl group-containing fluoropolymer coat A hydroxyl group-containing fluoropolymer (I) coat gas diffusion layer was produced in the same manner as in Example 3.
(Preparation of catalyst paste composition)
Using commercially available 46 wt% platinum-supported carbon (trade name: TEC10E50E, manufactured by Tanaka Kikinzoku Co., Ltd.), 1.5 g of platinum-supported carbon, 0.6 g of ion-exchange resin electrolyte for catalyst layer of Synthesis Example 3 (d), distilled water 0.9 g, 10.2 g of 1,2-dimethoxyethane and 2.2 g of normal propanol are mixed, and this mixture is stirred using a planetary ball mill (trade name: P-5, manufactured by Fritsch) until uniform. A catalyst paste was prepared.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Example 7]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Hydroxyl group-containing fluoropolymer coat A hydroxyl group-containing fluoropolymer (I) coat gas diffusion layer was produced in the same manner as in Example 4.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 7.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Example 8]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Hydroxyl-containing fluorinated polymer coat Hydroxyl-containing fluorinated polymer in the same manner as in Example 4 except that the hydroxyl-containing fluorinated polymer (ii) is used instead of the hydroxyl-containing fluorinated polymer (ii). B) A coating gas diffusion layer was prepared.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 7.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 1]
(Gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 2]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 7.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 3]
(Production of gas diffusion layer)
(1) Preparation of porous substrate Fluoropolymer (c) Coated porosity in the same manner as in Example 1 except that the fluoropolymer (c) is used instead of the hydroxyl group-containing fluoropolymer (a). A substrate was prepared.
(2) Formation of microporous layer Water repellent-coated porous group with a microporous layer in the same manner as in Example 1 except that the fluoropolymer (c) is used instead of the hydroxyl group-containing fluoropolymer (a). A material was prepared.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 4]
(Production of gas diffusion layer)
(1) Production of porous substrate A water-repellent-coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Fluorine-containing polymer instead of hydroxyl-containing fluorine-containing polymer (A) A water repellent coated porous substrate with a microporous layer was prepared in the same manner as in Example 1 except that the polymer (c) was used.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 5]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Fluorine-containing polymer coat Fluorine-containing polymer (c) Coat gas diffusion layer in the same manner as in Example 3 except that the fluorine-containing polymer (c) is used instead of the hydroxyl group-containing fluoropolymer (a). Was made.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 6]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Fluorine-containing polymer coat Fluorine-containing polymer (c) coated gas diffusion layer in the same manner as in Example 4 except that the fluorine-containing polymer (c) is used instead of the hydroxyl group-containing fluorine-containing polymer (a). Was made.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 7]
(Gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Fluorine-containing polymer coat Fluorine-containing polymer (c) coated gas diffusion layer in the same manner as in Example 4 except that the fluorine-containing polymer (c) is used instead of the hydroxyl group-containing fluorine-containing polymer (a). Was made.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 7.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 8]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Nafion Coat DuPont 20% Nafion (registered trademark) solution with normal propanol 5.5% by weight
Dilute to A water-repellent-coated porous substrate with a microporous layer was immersed in this solution for 5 minutes and dried in a drying furnace at 75 ° C. for 30 minutes to prepare a Nafion coat gas diffusion layer. The amount of Nafion deposited was 1.0 mg / cm2.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 9]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared.
(3) Formation of adhesive layer 4.45 g of 20% Nafion (registered trademark) solution manufactured by DuPont, 7.02 g of normal propanol, 7.42 g of distilled water, and 1.11 g of ketjen black EC are mixed, and this mixture is made into a planetary ball mill until uniform. (Product name: P-5, manufactured by Fritsch) was used to stir to prepare an adhesive layer paste. This paste was applied on a microporous layer of a water-repellent-coated porous substrate with a microporous layer with an applicator and then dried in a drying oven at 75 ° C. for 30 minutes. The coating amount after drying of the adhesive layer was 2 mg / cm ² .
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.
[Comparative Example 10]
(Production of gas diffusion layer)
(1) Production of porous substrate Water repellent coated porous substrate was produced in the same manner as in Example 2. (2) Formation of microporous layer Water repellent with microporous layer in the same manner as in Example 3. An agent-coated porous substrate was prepared. This gas diffusion layer was used for the cathode.
(3) Hydroxyl group-containing fluoropolymer coat A hydroxyl group-containing fluoropolymer (I) coat gas diffusion layer was produced in the same manner as in Example 4. This gas diffusion layer was used for the anode.
(Preparation of catalyst paste composition)
Anode and cathode catalyst pastes were prepared in the same manner as in Example 1.
(Catalyst-coated ion exchange resin membrane production)
A catalyst-coated ion exchange resin membrane was produced in the same manner as in Example 1.

  Table 1 shows the configurations and evaluation results of the membrane electrode assemblies of each Example and Comparative Example.

Claims (10)

In a membrane / electrode assembly including an ion exchange resin membrane, a catalyst layer, and a gas diffusion layer, the gas diffusion layer on the cathode side contains a hydroxyl group-containing component having the following structural units (a), (b), and (c). A stationary or portable fuel cell membrane electrode assembly comprising the fluoropolymer (A).
(A) A structural unit represented by the following formula (1).
(B) A structural unit represented by the following formula (2).
(C) A structural unit represented by the following formula (3).

[In the formula (1), R ¹ is a fluorine atom, a fluoroalkyl group or a group represented by —OR ² (R ²
Represents an alkyl group or a fluoroalkyl group)]

[In the formula (2), R ³ represents a hydrogen atom or a methyl group, R ⁴ represents an alkyl group, and a group represented by — (CH ₂ ) _x —OR ⁵ or —OCOR ⁵ (R ⁵ represents an alkyl group or a glycidyl group. , X represents a number of 0 or 1, and represents a carboxyl group or an alkoxycarbonyl group]

[In formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydroxyalkyl group, and v represents a number of 0 or 1]   The stationary or portable device according to claim 1, wherein the gas diffusion layer comprises a microporous layer in contact with the electrode layer and a porous base material layer in contact with the microporous layer, and the microporous layer contains the fluoropolymer (A). Type membrane electrode assembly for fuel cell.   The membrane electrode assembly for stationary or portable fuel cells according to claim 2, wherein the microporous layer and the porous base material layer contain the fluoropolymer (A).   The stationary or portable fuel cell membrane electrode assembly as described in any one of Claims 1-3 in which a gas diffusion layer contains the fluoropolymer (B) which does not have a hydroxyl group.   The membrane electrode assembly for stationary or portable fuel cells according to any one of claims 1 to 4, wherein the gas diffusion layers on the cathode side and the anode side contain a hydroxyl group-containing fluoropolymer (A).   The stationary or portable fuel cell membrane electrode assembly according to any one of claims 1 to 5, wherein the hydroxyl group-containing fluoropolymer (A) has a glass transition temperature of 30C to 160C. 7. The stationary or portable fuel cell membrane electrode assembly according to any one of claims 1 to 6, wherein the hydroxyl group-containing fluoropolymer (A) is insoluble in water. At least one of the catalyst layer on the anode side and the cathode side includes a structural unit represented by the following general formula (A) and a structural unit represented by the following general formula (B). The membrane / electrode assembly for a stationary or portable fuel cell according to claim 1, which is a polyarylene having a group.

(Wherein, Y is _{-CO -, - SO 2 -,} - SO -, - CONH -, - COO -, - (CF 2) l
- (l is an integer of 1 to _{10), - C (CF 3)} 2 - represents at least one structure selected from the group consisting of, Z is a direct bond _{or, - (CH 2) l -} ( l is an integer of 1 to 10), at least one structure selected from the group consisting of —C (CH ₃ ) ₂ —, —O—, and —S—, and Ar represents —SO ₃ H or — An aromatic group having a substituent represented by O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H is shown. p shows the integer of 1-12, m shows the integer of 0-10, n shows the integer of 0-10, k shows the integer of 1-4. )

(In the formula, A and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH.
-, - COO -, - ( CF 2) l - (l is an integer of 1 to _{10), - (CH 2) l} - (l is an integer of 1 to 10), - CR _'2 - ( R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, —O—, or —S—. B represents independently an oxygen atom or a sulfur atom, R ^{1 to} R ¹⁶ may be the same or different from each other, and a hydrogen atom, a fluorine atom, an alkyl group, part or all of which are halogenated It represents at least one atom or group selected from the group consisting of halogenated alkyl groups, allyl groups, aryl groups, nitro groups, and nitrile groups. s and t represent an integer of 0 to 4, and r represents 0 or an integer of 1 or more. )   A stationary or portable fuel cell comprising the membrane electrode assembly according to any one of claims 1 to 8. A resin paste for a gas diffusion layer of a stationary or portable fuel cell, comprising a hydroxyl group-containing fluoropolymer (A) having the following structural units (a), (b) and (c).
(A) A structural unit represented by the following formula (1).
(B) A structural unit represented by the following formula (2).
(C) A structural unit represented by the following formula (3).

[In the formula (1), R ¹ is a fluorine atom, a fluoroalkyl group or a group represented by —OR ² (R ²
Represents an alkyl group or a fluoroalkyl group)]

[In the formula (2), R ³ represents a hydrogen atom or a methyl group, R ⁴ represents an alkyl group, and a group represented by — (CH ₂ ) _x —OR ⁵ or —OCOR ⁵ (R ⁵ represents an alkyl group or a glycidyl group. , X represents a number of 0 or 1, and represents a carboxyl group or an alkoxycarbonyl group]

[In formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a hydrogen atom or a hydroxyalkyl group, and v represents a number of 0 or 1]