JP4993024B1 - Membrane-electrode assembly for fuel cell, method for producing the same, and polymer electrolyte fuel cell using the membrane-electrode assembly - Google Patents

Abstract

An object of the present invention is to provide a membrane-electrode assembly having high adhesion between a catalyst layer and a conductive porous layer.
In the membrane-electrode assembly of the present invention, a gas diffusion layer for a fuel cell is laminated on one side or both sides of a catalyst layer-electrolyte membrane laminate in which a catalyst layer, an electrolyte membrane, and a catalyst layer are sequentially laminated. A fuel cell membrane-electrode assembly, wherein the fuel cell gas diffusion layer has a conductive porous layer, and the catalyst layer and the conductive porous layer are in contact with each other. The conductive porous layer includes at least conductive carbon particles, and a glass transition temperature equal to or lower than the glass transition temperature of the electrolyte contained in the catalyst layer, and the electrolyte membrane. A polymer that satisfies at least one of the glass transition temperature of the hydrogen ion conductive resin that constitutes the polymer, and the polymer in the conductive porous layer has a catalyst layer rather than a surface that is not in contact with the catalyst layer. Densely on the surface in contact with A.
[Selection figure] None

Description

  The present invention relates to a membrane-electrode assembly for a fuel cell, a method for producing the same, and a polymer electrolyte fuel cell using the membrane-electrode assembly.

  The membrane-electrode assembly (MEA) constituting the polymer electrolyte fuel cell has a structure in which a gas diffusion layer, a catalyst layer, an ion conductive solid polymer electrolyte membrane, a catalyst layer, and a gas diffusion layer are sequentially laminated. ing.

  The reaction of the polymer electrolyte fuel cell proceeds at a three-phase interface in the catalyst layer where the catalyst particles, the electrolyte and the fuel gas are in contact. In order to obtain high power generation performance, moisture generated by the electrode reaction at this three-phase interface is efficiently discharged out of the electrode system so that the fuel gas can be supplied without stagnation, and the supplied fuel gas can be removed. It is important that the electrode catalyst layer is uniformly diffused. For this reason, it is necessary to dispose a gas diffusion layer in the vicinity of the catalyst layer in order to efficiently supply the fuel gas to the catalyst surface and enhance drainage in the electrode.

  In general, a conductive porous substrate such as carbon paper or carbon cloth is used for the gas diffusion layer. Furthermore, for the purpose of improving the conductivity, gas diffusibility, water discharge property, etc. of this conductive porous substrate, the conductive porous layer containing conductive carbon particles, water-repellent resin, etc. is changed to a conductive porous group. It may be formed on the material.

  However, since the conventional conductive porous layer uses only a fluororesin having a high glass transition temperature as in Patent Documents 1 and 2, the adhesion between the conductive porous layer and the catalyst layer is poor, and the battery There was a problem that performance was not stable. Moreover, in order to improve adhesiveness, it is necessary to join at a high temperature of 260 ° C. or higher. When such a process is performed, the hydrogen ion conductive polymer electrolyte contained in the catalyst layer and the resin constituting the electrolyte membrane As a result, the battery performance is adversely affected, and it has been difficult to actually bond under such conditions.

JP 2006-278037 A JP 2006-339018 A

  An object of the present invention is to provide a membrane-electrode assembly having high adhesion between a catalyst layer and a gas diffusion layer.

  In view of the above problems, the present inventors have made extensive studies to impart desired performance to a membrane-electrode assembly. As a result, it has been found that an integrated membrane-electrode assembly can be provided by applying a conductive porous layer containing a specific component to the gas diffusion layer. Specifically, the conductive porous layer is in contact with the catalyst layer, and the polymer in the conductive porous layer (the glass transition temperature is equal to or lower than the glass transition temperature of the electrolyte contained in the catalyst layer, and the electrolyte membrane) The gas diffusion layer is laminated on the catalyst layer-electrolyte membrane laminate so that at least one of the following resins constituting the resin is present more closely on the surface in contact with the catalyst layer than on the surface not in contact with the catalyst layer Thus, a membrane-electrode assembly integrated with the catalyst layer-electrolyte membrane laminate can be provided. The present invention has been completed based on such findings.

That is, the present invention relates to the following fuel cell membrane-electrode assembly and a polymer electrolyte fuel cell using the same.
Item 1. A fuel cell membrane-electrode assembly in which a fuel cell gas diffusion layer is laminated on one or both sides of a catalyst layer-electrolyte membrane laminate in which a catalyst layer, an electrolyte membrane, and a catalyst layer are sequentially laminated,
The fuel cell gas diffusion layer has a conductive porous layer, and is laminated on the catalyst layer-electrolyte membrane laminate so that the catalyst layer and the conductive porous layer are in contact with each other.
The conductive porous layer includes at least conductive carbon particles, and a glass transition temperature equal to or lower than a glass transition temperature of a hydrogen ion conductive polymer electrolyte contained in the catalyst layer, and a hydrogen ion conductive resin constituting the electrolyte membrane. high molecular weight polymer satisfying at least one of the following glass transition temperature be comprised by drying the containing Mushirubeden porous layer forming paste composition,
The membrane-electrode assembly for a fuel cell, wherein the polymer in the conductive porous layer is present more closely on the surface in contact with the catalyst layer than on the surface not in contact with the catalyst layer.
Item 2. The glass transition temperature of the polymer in the conductive porous layer is equal to or lower than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer, and the hydrogen ions constituting the electrolyte membrane Item 2. The fuel cell membrane-electrode assembly according to Item 1, which is not higher than the glass transition temperature of the conductive resin.
Item 3. Item 3. The fuel cell membrane-electrode assembly according to Item 1 or 2, wherein a conductive porous substrate is laminated on the conductive porous layer.
Item 4. Item 4. The fuel cell membrane-electrode assembly according to Item 3, wherein the conductive porous substrate is carbon paper, carbon cloth, or carbon nonwoven fabric.
Item 5. Item 5. The fuel cell membrane-electrode assembly according to Item 3 or 4, wherein the conductive porous substrate is provided with water repellency by a fluororesin.
Item 6. The method for producing a membrane-electrode assembly for a fuel cell according to any one of Items 1 to 5,
(I) On the substrate, at least conductive carbon particles, and the glass transition temperature is equal to or lower than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer, and the hydrogen ion conductive resin constituting the electrolyte membrane After applying and drying a conductive porous layer-forming paste composition containing a polymer that satisfies at least one of the glass transition temperature below the conductive transition layer, the conductive porous layer is peeled off from the substrate, A step of producing a conductive porous layer in which a polymer is present more densely than the opposite surface, and (II) the conductive porous layer on one side or both sides of the catalyst layer-electrolyte membrane laminate. A method for producing a membrane-electrode assembly for a fuel cell, comprising a step of disposing the conductive porous layer so that a dense polymer polymer surface and a catalyst layer face each other, and heat-integrating them.
Item 7. In step (II), at least one of the temperature of the hot press is not higher than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer and not higher than the glass transition temperature of the hydrogen ion conductive resin constituting the electrolyte membrane. Item 7. A method for producing a membrane-electrode assembly for a fuel cell according to Item 6, wherein
Item 8. In step (II), the temperature of the hot press is not higher than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer and not higher than the glass transition temperature of the hydrogen ion conductive resin constituting the electrolyte membrane. Item 8. A method for producing a membrane-electrode assembly for a fuel cell according to Item 6 or 7.
Item 9. Item 6. A polymer electrolyte fuel cell comprising the fuel cell membrane-electrode assembly according to any one of Items 1 to 5.

1. Membrane-electrode assembly for fuel cell The membrane-electrode assembly of the present invention is a catalyst layer-electrolyte membrane laminate in which a gas diffusion layer having a conductive porous layer is sequentially laminated with a catalyst layer, an electrolyte membrane and a catalyst layer. Are laminated on one or both sides. In the membrane-electrode assembly of the present invention, the gas diffusion layer is laminated so that the catalyst layer of the catalyst layer-electrolyte membrane laminate and the conductive porous layer of the gas diffusion layer are in contact with each other.

(1) Gas diffusion layer for fuel cells The gas diffusion layer for fuel cells used in the present invention has a conductive porous layer. The conductive porous layer is a layer containing at least conductive carbon particles and a polymer.

<Conductive porous layer>
The conductive porous layer contains at least conductive carbon particles and a polymer. The thickness of the conductive porous layer is not limited, but is usually about 1 μm to 150 μm, preferably about 5 μm to 100 μm. In the present invention, a gas diffusion layer having excellent gas diffusion characteristics and water management characteristics can be formed by providing a conductive porous layer.

Conductive carbon particles The conductive carbon particles are not particularly limited as long as they are conductive carbon materials, and known or commercially available ones can be used. Examples thereof include carbon black such as channel black, furnace black, ketjen black, acetylene black and lamp black; graphite; activated carbon and the like. These can be used alone or in combination of two or more. By containing these conductive carbon particles, the conductivity of the gas diffusion layer can be improved.

  When carbon black is used as the conductive carbon particles, the average particle diameter (arithmetic average particle diameter) of carbon black is not limited, and is usually about 5 nm to 200 nm, preferably about 5 nm to 100 nm. When carbon black aggregates are used, the thickness may be about 10 to 600 nm, preferably about 50 to 500 nm. When graphite, activated carbon or the like is used, the average particle size may be about 500 nm to 40 μm, preferably about 1 μm to 35 μm. The average particle size of the conductive carbon particles can be measured by, for example, a particle size distribution measuring device LA-920: manufactured by Horiba, Ltd.

As a high molecular polymer , the glass transition temperature (Tg) is equal to or lower than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer, and the hydrogen ion conductive resin constituting the electrolyte membrane. The resin is not limited as long as it is a resin satisfying at least one of the glass transition temperature (Tg) or less (the resin referred to in the present invention is a concept including an elastomer or the like), and a known or commercially available one can be used. The glass transition temperature of the polymer is specifically preferably about -30 to 220 ° C, more preferably about -20 to 210 ° C. For example, the same hydrogen ion conductive resin as the electrolyte membrane described later may be used, or the same resin component as the hydrogen ion conductive polymer electrolyte contained in the catalyst layer may be used. May be. Specifically, ion conductive polymer resins (Nafion, etc.), vinyl acetate resins, styrene-acrylic copolymer resins, styrene-vinyl acetate copolymer resins, ethylene-vinyl acetate copolymer resins, polyester-acrylic copolymers. Examples thereof include polymer resins, urethane resins, acrylic resins, and polyvinylidene fluoride (PVDF). Moreover, fluororubber, silicone rubber, etc., such as a hexafluoropropylene-vinylidene fluoride copolymer and a trifluoroethylene chloride-vinylidene fluoride copolymer, are also mentioned. These high molecular polymers may be used alone or in combination of two or more.

  If an elastomer such as fluororubber is used as the polymer, the flexibility of the conductive porous layer can be improved, and the adhesiveness with other layers can be improved because the Tg of the elastomer is low. In addition, elasticity and strength can be expressed. In addition, in this specification, fluororubber is a thing with Tg of about -30-100 degreeC. Therefore, it is easy to produce a membrane-electrode assembly using a gas diffusion layer having a conductive porous layer.

  The elastomer may be an elastomer emulsion (a suspension in which elastomer particles are dispersed) or an elastomer dissolved in a dispersion medium. When using an elastomer emulsion, the elastomer may be dispersed in a dispersion medium for adjustment, or a commercially available product may be used. Examples of the dispersion medium include water, ethanol, propanol, and the like. Examples of the dispersion medium in the case of using an elastomer dissolved in the dispersion medium include N-methylpyrrolidone (NMP), methyl ethyl ketone (MEK), toluene, vinyl acetate, dimethylacetamide (DMA), isopropyl alcohol (IPA), and the like. Can be mentioned.

  Moreover, since water repellency is imparted to the conductive porous layer, a water repellant resin such as a fluororesin can be used to the extent that the effects of the present invention are not hindered. In particular, when a polymer having poor water repellency is used as the polymer, it is effective for improving water repellency. Examples of such a fluororesin include polytetrafluoroethylene resin (PTFE), fluorinated ethylene propylene resin (FEP), perfluoroalkoxy resin (PFA), and the like.

  In the present invention, in the conductive porous layer forming paste composition, in addition to the conductive carbon particles and the polymer, the conductive carbon fiber, the dispersant, Alcohol etc. can also be included. A polymer having a large Tg may also be included as long as the effects of the present invention are not impaired.

Conductive carbon fiber By adding conductive carbon fiber, not only can the surface quality of the coated surface of the paste composition for forming a conductive porous layer be improved, but also a highly conductive sheet-like conductive porous layer Can also be made. The conductive carbon fiber used in the conductive porous layer is not particularly limited. For example, vapor grown carbon fiber (VGCF (registered trademark)), carbon nanotube, carbon nanowall, carbon nano A cup etc. are mentioned. These conductive carbon fibers may be used alone or in combination of two or more.

  The fiber diameter of the conductive carbon fiber is not particularly limited, but the average may be about 50 to 450 nm, preferably about 100 to 250 nm. By using such conductive carbon fibers, it is possible to increase the fine pore volume on the order of nanometers and to expect effects such as flooding resistance by improving gas diffusion performance and drainage performance. The fiber length is not limited, and the average may be 4 to 50 μm, preferably about 10 to 20 μm. The average aspect ratio is about 5 to 600, preferably about 10 to 500. The fiber diameter, fiber length, and aspect ratio of the conductive carbon fiber can be measured by an image measured with a scanning electron microscope (SEM) or the like.

The dispersant dispersant is not limited as long as it can disperse the conductive carbon particles and the polymer in water, and a known or commercially available dispersant can be used. Examples of such a dispersant include nonionic dispersants such as polyoxyethylene distyrenated phenyl ether, polyoxyethylene alkylene alkyl ether, and polyethylene glycol alkyl ether; alkyl trimethyl ammonium salt, dialkyl dimethyl ammonium chloride, alkyl pyridium. Examples thereof include cationic dispersants such as chloride; anionic dispersants such as polyoxyethylene fatty acid esters and acidic group-containing structure-modified polyacrylates. These dispersing agents can be used alone or in combination of two or more.

It does not specifically limit as alcohol alcohol, What is necessary is just to use a well-known or commercially available thing, For example, C1-C5 monohydric or polyhydric alcohol is mentioned. Specific examples include methanol, ethanol, 1-propanol, isopropanol, 1-butanol, and 1-pentanol.

<Characteristics of conductive porous layer>
In the present invention, the conductive porous layer has different polymer polymer component ratios on the front and back sides. That is, in the conductive porous layer, the polymer present on one surface is present more densely than the opposite surface. In the present invention, when two or more kinds of the above-described polymer are included, at least one of the polymers may be present on a certain one surface more densely than the opposite surface. The distribution state of the polymer component in the conductive porous layer can be confirmed by analyzing both surfaces by, for example, energy dispersive X-ray fluorescence analysis. The distribution of the polymer component can also be analyzed by performing energy dispersive X-ray fluorescence analysis in the layer cross-sectional direction. In addition, when using a styrene-acrylic acid-based rubber or the like, if the element specific to the polymer is not detected by energy dispersive X-ray fluorescence analysis, the polymer is analyzed by a Fourier transform infrared spectrophotometer or the like. What is necessary is just to observe the functional group resulting from a polymer.

<Method for producing conductive porous layer>
In the present invention, the conductive porous layer can be obtained, for example, by applying and drying a conductive porous layer forming paste composition on a substrate and peeling the substrate.

  When the conductive porous layer is formed by the method as described above, the polymer component contained in the conductive porous layer forming paste composition is in contact with the substrate when the paste composition is dried. By utilizing the phenomenon of segregation from the surface side that is not in contact to the surface side in contact with the substrate, the ratio of the polymer component present on the surface of the conductive porous layer can be adjusted. Therefore, the amount of the polymer used, the viscosity of the paste composition, the particle size when using an elastomer emulsion as the polymer, the drying time, the specific gravity of the carbon material (conductive carbon particles, conductive carbon fibers, etc.) The density of the polymer component can be increased on one surface by adjusting the functional group on the surface of the carbon material (conductive carbon particles, conductive carbon fiber, etc.). In particular, as the viscosity of the paste composition is lower and the drying time is longer, the resin tends to be segregated (see Table 1).

Content The blending ratio of the conductive porous layer forming paste composition is, for example, conductive carbon particles (when conductive carbon fibers are included, the total amount of conductive carbon particles and conductive carbon fibers) is 100 weights. Part of the polymer, about 30 to 200 parts by weight (preferably 40 to 150 parts by weight), about 0 to 100 parts by weight (preferably 5 to 50 parts by weight) of dispersant, 0 to 1100 parts by weight of alcohol or water. Part (preferably 100 to 1000 parts by weight). When the conductive carbon fiber is included, the content ratio of the conductive carbon particles to the conductive carbon fiber is about 9: 1 (weight ratio) to 1: 9 (weight ratio), particularly 8: 2 ( Weight ratio) to about 2: 8 (weight ratio) is preferable. In order to improve water repellency, about 5 to 250 parts by weight (preferably 10 to 200 parts by weight) of a fluororesin may be included. In addition, what is necessary is just to make solid content in the said range, when using an elastomer emulsion as a high molecular polymer. When the conductive porous layer forming paste composition contains a resin component having a large Tg, such as a fluororesin, the content ratio of the high molecular polymer and the resin component having a large Tg is 9 : 1 (weight ratio) to about 4: 6 (weight ratio), especially about 8: 2 (weight ratio) to about 5: 5 (weight ratio) is preferable.

  The conductive porous layer forming paste composition contains the components described above.

  A base material will not be specifically limited if a paste composition can be apply | coated, A well-known or commercially available base material can be used widely. Examples of such a substrate include polyimide, polyethylene terephthalate, polyparabanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyether ether ketone, polyetherimide, polyarylate, and polyethylene naphthalate. And polymer films such as polypropylene. Also, use ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluorofluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. Can do. Among these, a polymer film excellent in heat resistance and easily available is preferable. For example, films of polyethylene terephthalate, polyethylene naphthalate, polytetrafluoroethylene (PTFE), polyimide, and the like are preferable.

  It is preferable that a release layer is laminated on the substrate. Examples of the release layer include those composed of known waxes. Moreover, you may use the film etc. which were coated with SiOx, a fluororesin, etc. as a base material with which the release layer was laminated | stacked.

  The thickness of the substrate is usually about 6 to 100 μm, preferably about 10 to 60 μm, from the viewpoints of handleability and economy.

  As a coating method, a blade such as a known or commercially available doctor blade, a wire bar, a tool such as a squeegee, an applicator, a die coat or the like may be used.

  The coating amount of the paste composition is not limited, but for example, the thickness may be about 1 to 150 μm, preferably about 5 to 100 μm.

  Also, the drying conditions are not limited, and may be appropriately changed depending on conditions such as the volatilization temperature of the solvent (alcohol or the like) to be used, the glass transition temperature of the polymer, and the like.

<Characteristics of gas diffusion layer for fuel cells>
In the present invention, the fuel cell gas diffusion layer has the above-described conductive porous layer. In the conductive porous layer, the existing high molecular polymers are different from each other in the proportion of the high molecular polymers. In addition, in the case where a plurality of high molecular polymers are included in the conductive porous layer, at least one high molecular polymer (Tg is included in the catalyst layer) included in the conductive porous layer. The high molecular polymer satisfying at least one of the glass transition temperature of the hydrogen ion conductive polymer electrolyte and the glass transition temperature of the hydrogen ion conductive resin constituting the electrolyte membrane is different between the front and back sides. Just do it. In the present invention, the conductive porous layer can be used as it is as a gas diffusion layer.

<Conductive porous substrate>
On the gas diffusion layer, a known or commercially available gas diffusion layer (carbon paper, carbon cloth, carbon felt, etc.) may be formed as a conductive porous substrate.

When referring to TGP-H-060 manufactured by Toray Industries, Inc. as an example, the characteristics of commonly used carbon paper are as follows: thickness: 190 μm, electric resistance: thickness direction 80 mΩ · cm, surface direction 5.8 mΩ · cm, porosity: 78%, bulk density: 0.44 g / cm ³ , surface roughness: 8 μm, and the like. The thickness of the carbon paper or the like is not limited, but is usually about 50 to 1000 μm, preferably about 100 to 400 μm.

  It is preferable that the conductive porous substrate has been subjected to a water repellent treatment in advance. Thereby, the water repellency of the conductive porous substrate can be further improved.

  Examples of the water repellent treatment include a method of immersing the conductive porous substrate in an aqueous dispersion in which a fluorine resin or the like is dispersed. Examples of the fluorine-based resin include those described above. In this case, in order to disperse the fluororesin in water, the above-described dispersant is preferably used as an aqueous suspension containing the fluororesin and the aqueous dispersant.

  The content of the fluororesin in the aqueous dispersion is not limited, but may be, for example, about 1 to 30 parts by weight, preferably about 2 to 20 parts by weight with respect to 100 parts by weight of water.

(2) Catalyst layer-electrolyte membrane laminate <electrolyte membrane>
The electrolyte membrane is not limited as long as it is hydrogen ion conductive, and a known or commercially available membrane can be used. Specific examples of the electrolyte membrane include, for example, “Nafion” (registered trademark) membrane manufactured by DuPont, “Flemion” (registered trademark) membrane manufactured by Asahi Glass Co., Ltd., and “Aciplex” (registered trademark) manufactured by Asahi Kasei Corporation. ) Membrane, “Gore Select” (registered trademark) membrane manufactured by Gore, and the like.

  The thickness of the electrolyte membrane is usually about 20 to 250 μm, preferably about 20 to 150 μm.

<Catalyst layer>
As the catalyst layer, a known or commercially available platinum-containing catalyst layer (cathode catalyst or anode catalyst) can be used. Specifically, the catalyst layer is composed of (1) a dried product of a paste composition for forming a catalyst layer containing carbon particles supporting catalyst particles and (2) a hydrogen ion conductive polymer electrolyte. is there.

  The catalyst particles are not limited as long as they have an oxidation-reduction reaction (oxidation of hydrogen at the anode and reduction of oxygen at the cathode) and have catalytic activity. For example, platinum, platinum alloys, platinum compounds, etc. Is mentioned. Examples of the platinum alloy include an alloy of platinum and at least one metal selected from ruthenium, palladium, nickel, molybdenum, iridium, iron, and cobalt.

  Examples of the hydrogen ion conductive polymer electrolyte include perfluorosulfonic acid-based fluorine ion exchange resins, more specifically, perfluorocarbon sulfone in which the C—H bond of the hydrocarbon ion-exchange membrane is substituted with fluorine. Examples include acid-based polymers (PFS-based polymers).

  The thickness of the catalyst layer is not limited, but is usually about 1 to 100 μm, preferably about 2 to 50 μm.

  Note that a fluorine resin, non-polymer fluorine material such as fluorinated pitch, fluorinated carbon, and fluorinated graphite can be added to the catalyst layer as a water repellent.

<Method for producing catalyst layer-electrolyte membrane laminate>
The catalyst layer-electrolyte membrane laminate is, for example, a catalyst layer transfer film disposed so that the catalyst layer and the electrolyte membrane face each other, and the catalyst layer is transferred to the electrolyte membrane by applying pressure under heating conditions. It can be manufactured by peeling off. If this operation is repeated twice, a catalyst layer-electrolyte membrane laminate in which a catalyst layer is laminated on both sides of the electrolyte membrane can be produced. However, considering workability and the like, the catalyst layer is placed on both sides of the electrolyte membrane. It is good to laminate at the same time.

  When transferring, it may be pressurized from the base film side of the catalyst layer transfer film using a known press machine or the like. The pressure level at that time is usually about 0.5 to 10 MPa, preferably about 1 to 8 MPa in order to avoid transfer failure. Further, it is preferable to heat the pressure surface during this pressure operation in order to avoid transfer failure. What is necessary is just to change a heating temperature suitably with the kind of electrolyte membrane to be used.

  In addition, it does not restrict | limit especially as a base film, The thing similar to the above-mentioned base material can be used. For example, polymer films such as polyimide, polyethylene terephthalate (PET), polysulfone, polyethersulfone, polyphenylene sulfide, polyether ether ketone, polyetherimide, polyarylate, polyethylene naphthalate (PEN), polyethylene, polypropylene, polyolefin, etc. Can be mentioned. Also, ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE) It is also possible to use a heat-resistant fluororesin such as Among these, a polymer film that is inexpensive and easily available is preferable, and polyethylene terephthalate or the like is more preferable.

  The thickness of the base film is usually about 6 to 150 μm, preferably about 12 to 75 μm, from the viewpoints of workability and economical efficiency for forming a catalyst layer on the base film.

  Moreover, the base film may be one in which a release layer is laminated. Examples of the release layer include those composed of known waxes, known SiOx, plastic films coated with a fluorine-based resin, and the like. Moreover, what was comprised by laminating | stacking a film with high mold release property on a base film, for example, what has structures, such as a laminated body of a PET base material and a heat resistant fluororesin base material, may be used.

(3) Manufacturing method of fuel cell membrane-electrode assembly In the present invention, first,
(I) On the substrate, at least conductive carbon particles, and the glass transition temperature is equal to or lower than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer, and the hydrogen ion conductive resin constituting the electrolyte membrane After applying and drying a conductive porous layer-forming paste composition containing a polymer that satisfies at least one of the glass transition temperature below the conductive transition layer, the conductive porous layer is peeled off from the substrate, The conductive porous layer is formed by a step of producing a conductive porous layer in which the polymer is present more densely than the opposite surface.

further,
(II) The conductive porous layer is arranged on one side or both sides of the catalyst layer-electrolyte membrane laminate so that the dense polymer polymer surface of the conductive porous layer faces the catalyst layer. The membrane-electrode assembly of the present invention is obtained by the process of hot pressing and integration.

  In the step (II), the temperature of the hot press is at least not higher than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer and not higher than the glass transition temperature of the hydrogen ion conductive resin constituting the electrolyte membrane. One may be satisfied, but it is preferably not higher than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer and not higher than the glass transition temperature of the hydrogen ion conductive resin constituting the electrolyte membrane. . Specifically, when the hydrogen ion conductive resin constituting the electrolyte and the electrolyte membrane contained in the catalyst layer is Nafion, the temperature is preferably about 30 to 130 ° C, more preferably about 50 to 120 ° C. Moreover, in the case of the electrolyte resin used with a phosphoric acid fuel cell, about 130-220 degreeC is preferable and about 140-210 degreeC is more preferable. By setting the hot press temperature within the above range, an integrated membrane-electrode assembly is produced without altering the hydrogen ion conductive polymer electrolyte contained in the catalyst layer and the resin constituting the electrolyte membrane. be able to.

2. Solid polymer fuel cell By providing a known or commercially available separator to the membrane-electrode assembly of the present invention, a solid polymer fuel cell comprising the membrane-electrode assembly of the present invention can be obtained.

  According to the present invention, a gas diffusion layer having a conductive porous layer is used to integrate with a catalyst layer-electrolyte membrane laminate to provide a membrane-electrode assembly having high adhesion between the catalyst layer and the gas diffusion layer. can do.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

<Material>
For the preparation of the conductive porous layer forming paste composition, the following materials were used unless otherwise specified.
Conductive carbon particles: Furnace black (Vulcan xc72R: manufactured by Cabot Corporation), average molecular weight 1000 to 3000
Fluorine resin: Polytetrafluoroethylene (PTFE) (AD911L: Asahi Glass Co., Ltd.)
Polymer (1): Nafion (using 5 wt% Nafion solution “DE-520” manufactured by DuPont), Tg: 130 ° C.
Polymer (2): AP-2675 (manufactured by Showa Denko KK; emulsion using styrene-acrylic acid copolymer resin; solid content 50 wt%), Tg: 0 ° C.
Conductive carbon fiber: VGCF (VGCF (registered trademark) (standard product): manufactured by Showa Denko KK; average fiber diameter 150 nm, average fiber length 10-20 μm, average aspect ratio 10-500)
Dispersant: Emulgen A60 (manufactured by Kao Corporation)

<Manufacture of catalyst layer-electrolyte membrane laminate>
Using a known material, a catalyst layer-electrolyte membrane laminate was produced by a known method. Specifically, it is as follows.

  4 g of platinum catalyst-supporting carbon particles (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., “TEC10E50E”), 40 g of an ion conductive polymer electrolyte solution (Nafion 5 wt% solution: “DE-520” manufactured by DuPont), 12 g of distilled water, n-butanol 20 g of t-butanol and 20 g of t-butanol were mixed and stirred and mixed in a disperser to obtain a paste composition for forming an anode catalyst layer and a paste composition for forming a cathode catalyst layer.

By applying the paste composition for forming an anode catalyst layer and the paste composition for forming a cathode catalyst layer on a transfer substrate (material: polyethylene terephthalate film) using an applicator, and drying at 95 ° C. for about 30 minutes. A catalyst layer was formed to prepare an anode catalyst layer forming transfer sheet and a cathode catalyst layer forming transfer sheet. The coating amount of the catalyst layer was such that the platinum loading amount was about 0.45 mg / cm ^{2 for} both the anode catalyst layer and the cathode catalyst layer.

  Using the anode catalyst layer-forming transfer sheet and the cathode catalyst layer-forming transfer sheet prepared as described above, the electrolyte membrane (“NR-212” manufactured by DuPont; film thickness of 50 μm) is formed on each surface at 135 ° C. and 5 MPa. After performing the heat press for a minute, only the transfer base material was peeled off to prepare an electrolyte membrane-catalyst layer laminate.

Examples 1-6 and Comparative Examples 1-6
<Example 1>
Conductive carbon particles 100 parts by weight, fluororesin 50 parts by weight, conductive carbon fiber 75 parts by weight, polymer (1) 1250 parts by weight (solid content 62.5 parts by weight), dispersant 25 parts by weight and water A conductive porous layer forming paste composition was prepared by dispersing 350 parts by weight by media dispersion. This conductive porous layer forming paste composition was applied on a polyethylene terephthalate (PET) film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The viscosity of the paste composition was a value of about 150 mPa · s at a shear rate of 1000 (1 / s). The viscosity of the paste composition was measured using hysica MCR301 manufactured by Anton Paar (a jig having a diameter of 50 mm and an angle of 1 ° was used). In addition, the same measurement was implemented also about the paste composition of the other Example and the comparative example. Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled from the PET film on which the release layer is formed, and a polymer polymer (polymer polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte membrane laminate. (1)) is brought into contact with the surface, and the membrane-electrode assembly of Example 1 is obtained by hot pressing under conditions of a press temperature of 100 ° C., a press pressure of 7.5 kN, and a press time of 2 minutes. Produced.

<Example 2>
Conductive carbon particles 100 parts by weight, fluororesin 50 parts by weight, conductive carbon fiber 75 parts by weight, polymer (1) 1250 parts by weight (solid content 62.5 parts by weight), polymer (2) A conductive porous layer forming paste composition was prepared by dispersing 200 parts by weight (solid content: 100 parts by weight), dispersing agent 25 parts by weight and water 350 parts by weight by media dispersion. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The paste composition had a shear rate of 1000 (1 / s) and a shear viscosity of about 130 mPa · s. Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled from the PET film on which the release layer is formed, and a polymer polymer (polymer polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte membrane laminate. The film of Example 2 was obtained by bringing the surface on which (1) and (2)) are densely in contact with each other and performing hot pressing under conditions of a pressing temperature of 100 ° C., a pressing pressure of 7.5 kN, and a pressing time of 2 minutes. An electrode assembly was produced.

<Example 3>
Conductive carbon particles 100 parts by weight, fluororesin 50 parts by weight, conductive carbon fiber 75 parts by weight, polymer (1) 1250 parts by weight (solid content 62.5 parts by weight), polymer (2) A conductive porous layer forming paste composition was prepared by dispersing 200 parts by weight (solid content: 100 parts by weight) and 350 parts by weight of water by media dispersion. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The paste composition had a shear rate of 1000 (1 / s) and a shear viscosity of about 130 mPa · s. Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled off from the PET film on which the release layer is formed, and a polymer (conductive polymer (polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte laminate. The membrane-electrode of Example 3 is brought into contact with the surface on which 1) and (2)) are densely contacted and hot pressed under conditions of a press temperature of 100 ° C., a press pressure of 7.5 kN, and a press time of 2 minutes. A joined body was produced.

<Example 4>
Conductive porous layer forming paste composition by dispersing 50 parts by weight of conductive carbon particles, 50 parts by weight of fluorine-based resin and 2000 parts by weight of polymer (1) (solid content of 100 parts by weight) by media dispersion. Was formulated. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The viscosity of the paste composition was a value of about 250 mPa · s at a shear rate of 1000 (1 / s). Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled off from the PET film on which the release layer is formed, and a polymer (conductive polymer (polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte laminate. 1)) is brought into contact with the surface, and the membrane-electrode assembly of Example 4 is produced by hot pressing under conditions of a press temperature of 100 ° C., a press pressure of 7.5 kN, and a press time of 2 minutes. did.

<Example 5>
Conductive porous material is obtained by dispersing 50 parts by weight of conductive carbon particles, 50 parts by weight of a fluororesin, 2000 parts by weight of a polymer (1) (solid content of 100 parts by weight) and 25 parts by weight of a dispersant by media dispersion. A paste composition for layer formation was prepared. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The viscosity of the paste composition was a value of about 250 mPa · s at a shear rate of 1000 (1 / s). Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled off from the PET film on which the release layer is formed, and a polymer (conductive polymer (polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte laminate. 1)) is brought into contact with the surface, and the membrane-electrode assembly of Example 5 is produced by hot pressing under conditions of a press temperature of 100 ° C., a press pressure of 7.5 kN, and a press time of 2 minutes. did.

<Example 6>
100 parts by weight of conductive carbon particles, 50 parts by weight of fluorocarbon resin, 75 parts by weight of conductive carbon fiber, 1250 parts by weight of the polymer (1), 25 parts by weight of dispersant and 1050 parts by weight of water are dispersed by media dispersion. Thus, a conductive porous layer forming paste composition was prepared. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The paste composition had a shear rate of 1000 (1 / s) and a shear viscosity of about 60 mPa · s. Then, it was made to dry for about 30 minutes in the drying furnace set to 95 degreeC, and the electroconductive porous layer was produced.

  The conductive porous layer is peeled from the PET film on which the release layer is formed, and a polymer polymer (polymer polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte membrane laminate. (1)) is placed in close contact with the surface, and heat-pressed under the conditions of a press temperature of 100 ° C., a press pressure of 7.5 kN, and a press time of 2 minutes, whereby the membrane-electrode bonding of Example 6 The body was made.

<Comparative Example 1>
Conductive carbon particles 100 parts by weight, fluororesin 50 parts by weight, conductive carbon fiber 75 parts by weight, polymer (1) 1250 parts by weight (solid content 62.5 parts by weight), dispersant 25 parts by weight and water A conductive porous layer forming paste composition was prepared by dispersing 350 parts by weight by media dispersion. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The viscosity of the paste composition was a value of about 150 mPa · s at a shear rate of 1000 (1 / s). Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled off from the PET film on which the release layer is formed, and the polymer polymer (polymer polymer ( The membrane-electrode assembly of Comparative Example 1 was produced by bringing the surface having a low density of 1)) into contact and performing hot pressing under conditions of a pressing temperature of 100 ° C., a pressing pressure of 7.5 kN, and a pressing time of 2 minutes.

<Comparative example 2>
Conductive carbon particles 100 parts by weight, fluororesin 50 parts by weight, conductive carbon fiber 75 parts by weight, polymer (1) 1250 parts by weight (solid content 62.5 parts by weight), polymer (2) A conductive porous layer forming paste composition was prepared by dispersing 200 parts by weight (solid content: 100 parts by weight), dispersing agent 25 parts by weight and water 350 parts by weight by media dispersion. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The paste composition had a shear rate of 1000 (1 / s) and a shear viscosity of about 130 mPa · s. Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled off from the PET film on which the release layer is formed, and a polymer (conductive polymer (polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte laminate. The membrane-electrode assembly of Comparative Example 2 was brought into contact with the sparse surface of 1) and (2)) and subjected to hot pressing under conditions of a pressing temperature of 100 ° C., a pressing pressure of 7.5 kN, and a pressing time of 2 minutes. Was made.

<Comparative Example 3>
Conductive carbon particles 100 parts by weight, fluororesin 50 parts by weight, conductive carbon fiber 75 parts by weight, polymer (1) 1250 parts by weight (solid content 62.5 parts by weight), polymer (2) A conductive porous layer forming paste composition was prepared by dispersing 200 parts by weight (solid content: 100 parts by weight) and 350 parts by weight of water by media dispersion. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The paste composition had a shear rate of 1000 (1 / s) and a shear viscosity of about 130 mPa · s. Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled off from the PET film on which the release layer is formed, and a polymer (conductive polymer (polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte laminate. The membrane-electrode assembly of Comparative Example 3 was brought into contact with the sparse surface of 1) and (2)) and hot-pressed under conditions of a press temperature of 100 ° C., a press pressure of 7.5 kN, and a press time of 2 minutes. Was made.

<Comparative example 4>
Conductive porous layer forming paste composition by dispersing 50 parts by weight of conductive carbon particles, 50 parts by weight of fluorine-based resin and 2000 parts by weight of polymer (1) (solid content of 100 parts by weight) by media dispersion. Was formulated. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. The viscosity of the paste composition was a value of about 250 mPa · s at a shear rate of 1000 (1 / s). Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled off from the PET film on which the release layer is formed, and a polymer (conductive polymer (polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte laminate. The membrane-electrode assembly of Comparative Example 4 was produced by contacting the surface with the sparse 1)) and performing hot pressing under conditions of a pressing temperature of 100 ° C., a pressing pressure of 7.5 kN, and a pressing time of 2 minutes.

<Comparative Example 5>
Conductive porous material is obtained by dispersing 50 parts by weight of conductive carbon particles, 50 parts by weight of a fluororesin, 2000 parts by weight of a polymer (1) (solid content of 100 parts by weight) and 25 parts by weight of a dispersant by media dispersion. A paste composition for layer formation was prepared. This conductive porous layer-forming paste composition was applied on a PET film on which a release layer was formed using an applicator so as to have a thickness of about 50 μm. Then, it was dried for about 15 minutes in a drying oven set at 95 ° C. to produce a conductive porous layer.

  The conductive porous layer is peeled off from the PET film on which the release layer is formed, and a polymer (conductive polymer (polymer) of the conductive porous layer is formed on the surface of the catalyst layer on the cathode side of the catalyst layer-electrolyte laminate. The membrane-electrode assembly of Comparative Example 5 was produced by bringing the surface having the sparse 1)) into contact and performing hot pressing under conditions of a pressing temperature of 100 ° C., a pressing pressure of 7.5 kN, and a pressing time of 2 minutes.

<Comparative Example 6>
Conductive carbon particles 100 parts by weight, PTFE 250 parts by weight (Daikin Industries, Ltd. Lubron LDW-41: 175 parts by weight, DuPont PTFE 31-JR: 75 parts by weight), conductive carbon fiber 25 parts by weight, dispersion 25 parts by weight of the agent and 850 parts by weight of water were dispersed by media dispersion to prepare a conductive porous forming paste composition (conducting carbon with respect to the total amount of conductive carbon particles and conductive carbon fibers). Fiber 20% by weight).

Further, the water-repellent layer was subjected to water-repellent treatment by adjusting the coating amount of the water-repellent layer to about 35 g / m ² and the coating thickness to about 35 μm. Carbon paper is used for the conductive porous substrate, and PTFE suspension (100 parts by weight of PTFE suspension is 60 parts by weight of PTFE and 2 parts of dispersing agent (polyoxyethylene alkylene alkyl ether) with respect to 100 parts by weight of water. 2 parts impregnated with 5 parts by weight of PTFE water dispersion, dried in air at 95 ° C. for about 15 minutes, and then in air at about 300 ° C. for 2 hours A water-repellent treatment was performed by firing to a certain extent.

Using the applicator (manufactured by Sheen Instruments Ltd, “Micrometer Adjustable Film Applicator, 1117/200”), the coating amount of the conductive porous layer forming paste composition prepared above was 35 g / m ^{2 in} terms of solid content. The water-repellent-treated conductive porous substrate was uniformly coated on one surface so as to reach a degree. Next, after drying at 95 ° C. for about 20 minutes in the air atmosphere, the conductive porous layer was formed on the surface of the water-repellent conductive porous substrate by firing at 300 ° C. for about 2 hours in the air atmosphere. A gas diffusion layer was manufactured. The conductive porous layer surface of the water-repellent treated porous substrate coated with the conductive porous layer is adjacent to the catalyst layer under the conditions of a press temperature of 100 ° C., a press pressure of 7.5 kN, and a press time of 2 minutes. A membrane-electrode assembly of Comparative Example 6 was produced by hot pressing.

<Evaluation test of conductive porous layer>
As a representative example, Table 1 shows the results of observation of the front and back surfaces of the conductive porous layers of Example 1 and Example 6 by energy dispersive X-ray fluorescence analysis. As a result, the presence ratio of F element and S element possessed by Nafion resin and PTFE resin is different between the front and back of the conductive porous layer, and both PTFE resin and Nafion resin are segregated on the front and back of the conductive porous layer. It was confirmed that Moreover, the difference of the result of Example 6 is remarkable compared with the result of Example 1, and it becomes easy to segregate resin more by making the paste composition for conductive porous layer formation low viscosity. It could be confirmed. Similar results are obtained for Examples 2 to 5. In Table 1, “PET film contact surface” refers to the surface that was in contact with the PET film before peeling the PET film from the conductive porous layer, and “PET film non-contact surface” refers to PET The surface opposite to the film contact surface is shown.

<Evaluation test of membrane-electrode assembly>
Using an intermediate temperature press device (manufactured by Tester Sangyo Co., Ltd.), the adhesion between the conductive porous layer and the catalyst layer in the membrane-electrode assemblies of Examples 1 to 6 and Comparative Examples 1 to 6 was measured.

In addition, evaluation of adhesiveness judged subjectively whether it adhered, without the layers peeling. In particular,
◯: It is firmly attached and cannot be easily peeled by hand. ×: It is judged that it can be easily peeled by hand or is not in close contact at all. The results are shown in Table 2.

  In order to show high adhesion between the conductive porous layer and the catalyst layer, as shown in Examples 1 to 6, the surface of the conductive porous layer on which the polymer is densely present and the catalyst layer are adjacent to each other. We confirmed the necessity of layering.

  From the above results, it is possible to produce an integrated membrane-electrode assembly by superimposing the surface of the conductive porous layer on which the polymer polymer is densely present and the catalyst layer adjacent to each other. It was confirmed that the entire electrode could be thinned.

Claims (9)

A fuel cell membrane-electrode assembly in which a fuel cell gas diffusion layer is laminated on one or both sides of a catalyst layer-electrolyte membrane laminate in which a catalyst layer, an electrolyte membrane, and a catalyst layer are sequentially laminated,
The fuel cell gas diffusion layer has a conductive porous layer, and is laminated on the catalyst layer-electrolyte membrane laminate so that the catalyst layer and the conductive porous layer are in contact with each other.
The conductive porous layer includes at least conductive carbon particles, and a glass transition temperature equal to or lower than a glass transition temperature of a hydrogen ion conductive polymer electrolyte contained in the catalyst layer, and a hydrogen ion conductive resin constituting the electrolyte membrane. high molecular weight polymer satisfying at least one of the following glass transition temperature be comprised by drying the containing Mushirubeden porous layer forming paste composition,
The membrane-electrode assembly for a fuel cell, wherein the polymer in the conductive porous layer is present more closely on the surface in contact with the catalyst layer than on the surface not in contact with the catalyst layer. The glass transition temperature of the polymer in the conductive porous layer is equal to or lower than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer, and the hydrogen ions constituting the electrolyte membrane The membrane-electrode assembly for a fuel cell according to claim 1, which is not higher than the glass transition temperature of the conductive resin. The membrane-electrode assembly for a fuel cell according to claim 1 or 2, wherein a conductive porous substrate is laminated on the conductive porous layer. The membrane-electrode assembly for a fuel cell according to claim 3, wherein the conductive porous substrate is carbon paper, carbon cloth, or carbon non-woven fabric. The membrane-electrode assembly for a fuel cell according to claim 3 or 4, wherein the conductive porous substrate is provided with water repellency by a fluororesin. A method for producing a membrane-electrode assembly for a fuel cell according to any one of claims 1 to 5,
(I) On the substrate, at least conductive carbon particles, and the glass transition temperature is equal to or lower than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer, and the hydrogen ion conductive resin constituting the electrolyte membrane After applying and drying a conductive porous layer-forming paste composition containing a polymer that satisfies at least one of the glass transition temperature below the conductive transition layer, the conductive porous layer is peeled off from the substrate, A step of producing a conductive porous layer in which a polymer is present more densely than the opposite surface, and (II) the conductive porous layer on one side or both sides of the catalyst layer-electrolyte membrane laminate. A method for producing a membrane-electrode assembly for a fuel cell, comprising a step of disposing the conductive porous layer so that a dense polymer polymer surface and a catalyst layer face each other, and heat-integrating them. In step (II), at least one of the temperature of the hot press is not higher than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer and not higher than the glass transition temperature of the hydrogen ion conductive resin constituting the electrolyte membrane. The manufacturing method of the membrane-electrode assembly for fuel cells of Claim 6 which satisfy | fills. In step (II), the temperature of the hot press is not higher than the glass transition temperature of the hydrogen ion conductive polymer electrolyte contained in the catalyst layer and not higher than the glass transition temperature of the hydrogen ion conductive resin constituting the electrolyte membrane. The manufacturing method of the membrane-electrode assembly for fuel cells of Claim 6 or 7. A polymer electrolyte fuel cell comprising the fuel cell membrane-electrode assembly according to any one of claims 1 to 5.