JP2008047431A - Holding sheet for manufacturing membrane electrode assembly for fuel cell and manufacturing method of membrane electrode assembly for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form an electrode catalyst layer by coating without generating wrinkles in a polymer electrolyte membrane and suppress contamination of the polymer electrolyte membrane caused by a holding sheet composition. <P>SOLUTION: The holding sheet used for manufacturing the membrane electrode assembly for a fuel cell having the electrode catalyst on both sides of a solid polymer electrolyte membrane is held by coming in contact with the solid polymer electrolyte membrane or the electrode catalyst layer, the holding sheet contains a polymer composition having main chains crosslinked with -N-(CH<SB>2</SB>)<SB>6</SB>-N- and carbon, and the contents of the carbon is 36-53 wt.% of the total amount of the polymer composition and the carbon. The manufacturing method of the membrane electrode assembly contains a first fixing process for fixing the solid polymer electrolyte membrane to the holding sheet, a first coating process for coating the fixed solid polymer electrolyte membrane with cathode catalyst layer paste or anode catalyst layer paste, and a first removing process for removing the holding sheet for manufacturing the membrane electrode assembly for the fuel cell from the solid polymer electrolyte membrane. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a membrane electrode structure for a fuel cell, and more particularly to a technique for suppressing soot generated when a catalyst is formed on an electrolyte membrane.

  Currently, depletion of petroleum resources is a serious problem, and environmental problems such as air pollution and global warming due to consumption of fossil fuels are becoming more serious. Under such circumstances, fuel cells have attracted attention as a clean electric power source for electric motors that does not generate carbon dioxide and have been extensively developed, and some have begun to be put into practical use.

  When a fuel cell is mounted on an automobile or the like, a solid polymer fuel cell using a polymer electrolyte membrane is preferably used because a high voltage and a large current can be easily obtained. As a membrane electrode structure used for a polymer electrolyte fuel cell, an ion conductive polymer electrolyte membrane is sandwiched between a pair of electrode catalyst layers, and a diffusion layer is laminated on each electrode catalyst layer. Are known. The electrode catalyst layer is formed by supporting a catalyst such as platinum on a catalyst carrier such as carbon black and integrating them with an ion conductive polymer binder. This membrane electrode structure forms a polymer electrolyte fuel cell by further laminating a separator also serving as a gas passage on each electrode catalyst layer.

  In such a polymer electrolyte fuel cell, one electrode catalyst layer is used as a fuel electrode, a reducing gas such as hydrogen or methanol is introduced through a diffusion layer, and the other electrode catalyst layer is used as an oxygen electrode for diffusion. An oxidizing gas such as air or oxygen is introduced through the layer. On the fuel electrode side, protons (H +) and electrons are generated from the reducing gas by the action of the catalyst contained in the electrode catalyst layer, and the protons move to the electrode catalyst layer on the oxygen electrode side through the polymer electrolyte membrane. . Then, protons react with the oxidizing gas and electrons introduced into the oxygen electrode by the action of the catalyst contained in the electrode catalyst layer in the electrode catalyst layer on the oxygen electrode side to generate water. Therefore, by connecting the fuel electrode and the oxygen electrode with a conducting wire, a circuit for sending electrons generated at the fuel electrode to the oxygen electrode is formed, and a current can be taken out.

  In order to produce such a membrane electrode structure, conventionally, a method in which an electrode catalyst layer is separately formed on a support, and this and a polymer electrolyte membrane are bonded together and thermocompression bonded is generally used. However, in this method, since the electrode catalyst layer is solidified and formed and then bonded onto the electrolyte membrane, there is a problem that it is difficult to make them adhere to each other and the contact resistance is high.

  For such problems, a technique for producing a membrane electrode structure by directly printing an electrode catalyst paste on the electrolyte membrane by screen printing, a bar coater, a doctor blade or the like and drying it (see, for example, Patent Document 1), A technique of applying an electrode catalyst layer slurry while adsorbing and holding a solid polymer electrolyte membrane on a plate by vacuuming (see, for example, Patent Document 2), and further, an electrode catalyst while holding the solid polymer electrolyte membrane on a holding sheet A technique for applying a layer slurry and removing the holding sheet after drying to obtain a membrane electrode structure (see, for example, Patent Document 3) has been proposed.

JP 2000-268829 A JP 2003-100314 A JP-A-2005-163808

  However, in the production method described in Patent Document 1, the polymer electrolyte membrane swells due to the solvent component contained in the printed electrode catalyst paste, and the electrode catalyst layer and the polymer electrolyte membrane shrink due to drying after printing. As a result, there is a problem that wrinkles are generated in the polymer electrolyte membrane. Furthermore, there is a problem that it is difficult to form an electrode catalyst layer having a desired shape and size on the polymer electrolyte membrane by coating. In addition, in the method described in Patent Document 2, it is difficult to handle the transfer of the solid polymer electrolyte membrane from the perforated plate being evacuated to the drying step, and the solid polymer electrolyte membrane may be damaged. It was. Furthermore, in the method described in Patent Document 3, the membrane electrode structure is formed while being held on the holding sheet, so that the problem of wrinkles can be solved. However, the resin component of the holding sheet is formed by the adhesive force of the sheet. A part (Si or SiO) is transferred to the membrane electrode structure after peeling and contaminates it, and after the subsequent heat treatment of the membrane electrode structure, it has an adverse effect, causing a decrease in conductivity and deterioration of durability. There was a problem of becoming.

  The present invention has been made in view of the above situation, and by applying an electrode catalyst layer on a polymer electrolyte membrane without causing wrinkles on the polymer electrolyte membrane by fixing the polymer electrolyte membrane on a holding sheet. In addition, an electrode catalyst layer having a desired shape can be formed. Further, when the holding sheet is peeled from the membrane electrode structure, the components of the holding sheet do not remain in the membrane electrode structure. An object of the present invention is to provide a fuel cell membrane electrode structure manufacturing holding sheet capable of preventing electrode structure contamination, and a fuel cell membrane electrode structure manufacturing method using the sheet.

The fuel cell membrane electrode structure production holding sheet of the present invention is a fuel cell membrane electrode structure used when producing a fuel cell membrane electrode structure comprising electrode catalyst layers on both sides of a solid polymer electrolyte membrane. A body-manufacturing holding sheet, which is held by contacting a solid polymer electrolyte membrane or an electrode catalyst layer, and a polymer component in which —N— (CH ₂ ) ₆ —N— is crosslinked between main chains; Carbon is contained, and the carbon content is 36 to 53% by weight based on the total amount of the polymer component and carbon.

  According to the present invention having the above-described configuration, since the holding sheet for manufacturing a fuel cell membrane electrode structure has an appropriate range of adhesive strength, the solid polymer electrolyte membrane is fixed at the time of forming the electrode catalyst layer, and soot is generated. While being suppressed, it can be peeled from the holding sheet after the molding without damaging the solid polymer electrolyte membrane and the electrode catalyst layer. Moreover, it can suppress that a solid polymer electrolyte membrane is contaminated with the component of a holding sheet.

In the holding sheet for producing the membrane electrode structure for a fuel cell, the main chain of the polymer component is a carboxyl group-based acrylic rubber represented by the following chemical formula (1), and —N— (CH ₂ ) A preferred form is that ₆ -N-crosslinking is performed.

（Ｙ、Ｚは整数、Ｒはアルキル基）

(Y and Z are integers, R is an alkyl group)

The —N— (CH ₂ ) ₆ —N— bridge in the carboxyl group of the main chain is preferably formed by reacting the carboxyl group of the main chain with hexamethylenediamine.

  The method for producing a fuel cell membrane electrode structure of the present invention is a method for producing a fuel cell membrane electrode structure in which a cathode electrode catalyst layer and an anode electrode catalyst layer are formed on a solid polymer electrolyte membrane, respectively. A first fixing step of installing the solid polymer electrolyte membrane on the above-mentioned holding sheet for manufacturing a fuel cell membrane electrode structure; and a cathode electrode catalyst layer paste or an anode electrode catalyst layer paste on the fixed solid polymer electrolyte membrane It has the 1st application process which apply | coats one of these, and the 1st removal process which removes a holding sheet from a solid polymer electrolyte membrane, It is characterized by the above-mentioned.

  According to the method for producing an electrode structure for a fuel cell of the present invention, when applying the cathode (or anode) electrode catalyst layer paste, the solid polymer electrolyte membrane is fixed from the back side of the paste application surface by the fixing of the holding sheet. Therefore, generation | occurrence | production of the wrinkle of the polymer electrolyte membrane resulting from the swelling of the solid polymer electrolyte membrane by the solvent contained in a paste can be suppressed.

  The present invention preferably includes a first drying step of a composite in which an electrode catalyst layer is provided on a solid polymer electrolyte membrane between the first coating step and the first removal step.

  The drying process of the composite after the application of the electrode catalyst layer paste can be performed at an arbitrary stage. In particular, according to such an embodiment, the solids high between the first application process and the first removal process. Since the molecular electrolyte membrane is fixed by fixing the holding sheet, it not only suppresses the shrinkage of the solid polymer electrolyte membrane during drying, but also breaks when handling it by moving it back and forth from the upstream to the downstream of the process during drying. Can be suppressed.

  In addition, the present invention includes a second fixing step in which the composite is turned over and the electrode catalyst layer side of the composite is placed on the holding sheet after the first removal step, and the solid polymer electrolyte membrane side of the fixed composite It is preferable to have a second application step of applying the other of the anode electrode catalyst layer paste or the cathode electrode catalyst layer paste and a second removal step of removing the holding sheet from the composite.

  According to such a form, when the electrode catalyst layer paste is applied, the already formed electrode catalyst layer is fixed by fixing the holding sheet, and this electrode catalyst layer further fixes the solid polymer electrolyte membrane. Occurrence of wrinkles of the solid polymer electrolyte membrane due to swelling of the solid polymer electrolyte membrane by the solvent contained in the paste can be suppressed.

  This invention makes it a preferable form to have a 2nd drying process of a composite_body | complex between a 2nd application | coating process and a 2nd removal process.

  According to such a form, like the drying process between the first application process and the first removal process, the electrode catalyst layer already applied is also applied between the second application process and the second removal process. Since it is fixed by the fixing of the holding sheet, the shrinkage of the solid polymer electrolyte membrane can be suppressed.

Hereinafter, preferred embodiments of the present invention will be described.
The fuel cell membrane electrode structure production holding sheet of the present invention is a fixing sheet used when producing a fuel cell membrane electrode structure having electrode catalyst layers on both sides of a solid polymer electrolyte membrane. . This holding sheet contains a polymer component and carbon in which —N— (CH ₂ ) ₆ —N— is cross-linked between main chains, and the carbon content is equal to the total amount of the polymer component and carbon. It is characterized by being 36 to 53% by weight.

  As an example of such a polymer component, it is preferable to use a carboxyl group-based acrylic rubber having a rubber polymer structure represented by the following chemical formula (1).

（Ｙ、Ｚは整数、Ｒはアルキル基）

(Y and Z are integers, R is an alkyl group)

  In the present invention, this polymer and hexamethylenediamine are reacted to crosslink carboxyl groups between the polymers. In the polymer in which the polymer of the chemical formula (1) is cross-linked, as shown in the chemical formula (2) below, one carboxyl group of each main chain is cross-linked to form one amide bond at each end of the cross-link. And a form having two amide bonds as shown in chemical formula (3), or a form in which these are mixed.

  In the present invention, the carbon to be mixed with the crosslinked polymer component is preferably 36 to 53% by weight with respect to the total amount of the polymer component and carbon because the adhesive strength is within an appropriate range. When the amount of carbon is less than 36% by weight, the adhesive strength of the holding sheet is too strong, and the membrane electrode structure is damaged when it is peeled off after forming the membrane electrode structure. On the other hand, the amount of carbon is 53% by weight. When it exceeds%, the adhesive strength of the holding sheet is insufficient, the membrane electrode structure is not sufficiently fixed, and wrinkles may be generated. Examples of the carbon to be added include FEF (Fast Extension Furnace), SRF (Semi-Reinforcing Furnace), and FT (Fine Thermal).

  The fuel cell membrane electrode structure production holding sheet of the present invention is prepared by blending various blending agents and vulcanizing agents with the polymer and carbon, and kneading them with a roll, a kneader intermix or a banbury, etc. The sheet can be formed by a Bowell molding machine or the like and vulcanized and molded by press molding, compression molding, transfer molding or injection molding to form a sheet. Specific embodiments of the holding sheet will be described later in Examples.

Next, a preferred embodiment of a manufacturing process of a membrane electrode structure using the holding sheet for manufacturing a membrane electrode structure for a fuel cell of the present invention will be described with reference to the drawings as appropriate.
FIG. 1 is a schematic diagram showing an embodiment of the present invention. In FIG. 1, the code | symbol 1 is a holding base material made from aluminum or SUS for performing a series of processes. On the holding substrate 1, a holding sheet 2 having adhesiveness is fixed.

  First, the solid polymer electrolyte membrane 3 is stuck on the holding sheet 2 (first fixing step). Subsequently, the cathode electrode catalyst layer paste 4 is applied onto the solid polymer electrolyte membrane 3 by an arbitrary application means 5 such as a bar coater or a doctor blade (first application step), and is kept fixed by the holding sheet 2. Then, the solid polymer electrolyte membrane 3 and the cathode electrode catalyst layer 4 are dried. After drying, they are peeled off from the holding sheet 2 (first removal step), turned over, and the cathode electrode catalyst layer 4 side is attached to the holding sheet 2 (second fixing step). The anode electrode catalyst layer paste 6 is applied onto the solid polymer electrolyte membrane 3 by the application means 5 (second application step), and the solid polymer electrolyte membrane 3 and the anode electrode catalyst layer are kept fixed by the holding sheet 2. 6 is dried. After drying, the film is peeled from the holding sheet 2 (second removal step) to obtain a membrane-electrode composite in which the cathode electrode catalyst layer 4 and the anode electrode catalyst layer 6 are formed on both surfaces of the solid polymer electrolyte membrane 3.

  A means for applying the cathode electrode catalyst layer paste and the anode electrode catalyst layer paste to the polymer electrolyte membrane is not particularly limited, such as screen printing, printing with a bar coater, or a doctor blade.

  In particular, when a doctor blade or a bar coater is used, a membrane-electrode composite in which an electrode catalyst layer is freely formed can be obtained by using a laminating film cut into a desired shape. Specifically, after the solid polymer electrolyte membrane is fixed on the holding sheet, a laminating film cut into a desired shape is stuck on the solid polymer electrolyte membrane. The cathode electrode catalyst layer paste is applied and dried within the cutout range of the laminating film, the solid polymer electrolyte membrane is peeled off from the holding sheet and turned over, and the cathode electrode catalyst layer side is fixed on the holding sheet. Subsequently, another laminating film cut into a desired shape is attached onto the solid polymer electrolyte membrane, and the anode electrode catalyst layer paste is similarly applied and dried. Finally, by removing the laminating films on both sides, a membrane-electrode assembly in which the electrode catalyst layer is freely formed can be obtained. The laminating film for the cathode electrode catalyst layer may be removed immediately after the cathode electrode catalyst layer is dried. Also in this embodiment, the order of application of the cathode and anode can be reversed.

  The holding sheet used in the present invention is required to have an appropriate range of adhesive strength. The method for measuring the adhesive strength is described in JIS Z0237. As shown in FIG. 2, the specimen 2 (and the holding substrate 1) of the holding sheet is bonded to the adherend 7, and one end thereof is peeled off and attached. It peels in the direction of 90 degrees with respect to the mating direction, and measures the force required for peeling. Specifically, measurement is performed using the adherend 7 as a stainless steel plate, and the adhesive strength is preferably 200 gf / 30 mm or more. If the adhesive strength is less than 200 gf / 30 mm, the fixing effect is not sufficient, swelling / shrinkage during application and drying of the electrode catalyst layer paste cannot be suppressed, and wrinkles occur due to partial peeling. End up.

  In the present invention, after the first fixing step, the first coating step, the first drying step, and the first removing step, the composite is turned over and the second fixing step, the second coating step, the second drying step, and the second removing step are performed. However, the method for producing the membrane electrode complex is not limited to this mode, and one electrode is formed by the first fixing step to the first drying step. After the formation of the catalyst layer, the other electrode catalyst layer can be formed by fixing the composite by other known methods such as vacuuming or electrostatic adsorption and performing the second coating step.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
A. Production of Holding Sheet for Manufacturing Membrane Electrode Structure The holding sheets of Examples 1 to 3 and Comparative Examples 1 to 4 were produced by the following method.

[Example 1]
1000 g of polymer A (carboxyl group-based acrylic polymer, trade name: AR-14, manufactured by Nippon Zeon Co., Ltd.) as a polymer component, and amine-based anti-aging agent (4,4′-bis (α, α-dimethylbenzyl) diphenylamine as a compounding agent ), Processing aid (higher fatty acid) 60 g, carbon (trade name: FEF grade seast 116, manufactured by Tokai Carbon Co., Ltd.) 600 g, vulcanizing agent (hexamethylene diamine carbamate, trade name: Diak # 1, manufactured by Dupont) 4 g, 16 g of vulcanization accelerator (1,3-di-orthotolylguanidine, trade name: Noxeller DT, manufactured by Ouchi Shinsei Chemical Co., Ltd.) is lightened with an electronic balance (trade name: EB2800-12, manufactured by Shimadzu Corporation) and rolled ( Kneading was performed using a product name: φ6 “× 15” test roll ll type EC-R-FE (manufactured by Irie Iron Works).

  At this time, when the temperature rises due to the heat generated by the kneading shear force, the vulcanizing agent starts to react and burns during vulcanization molding (the rubber surface becomes rough and a fluttering pattern appears). Kneading was carried out while adjusting the roll to 100 ° C. or less with cooling water, because the crosslinking reaction was accelerated during the flow and could cause fusion marks and cracks at the fusion site.

Part of the kneaded material is rolled out into a sheet with a thickness of 2.5 mm (when the pre-vulcanized rubber material is put into a rubber vulcanization mold, it is molded into a shape that matches the product weight and shape) And cut into a shape that matches the size of the sheet of 100 mm × 100 mm. The cut sheet is put in a 2 mm thick, 100 mm × 100 mm mold heated to 170 ° C. in advance, and 170 ° C. and 200 kgf / cm ² pressure at a press machine (100 t electric vulcanizing press, manufactured by Yasuda Seiki Seisakusho). The condition was maintained for 10 minutes, the rubber was vulcanized, and the target sheet of Example 1 was molded.

[Example 2]
A sheet of Example 2 was produced in the same manner as Example 1 except that 900 g of carbon was used.

[Example 3]
A sheet of Example 3 was produced in the same manner as Example 1 except that 1200 g of carbon was used.

[Comparative Example 1]
A sheet of Comparative Example 1 was produced in the same manner as Example 1 except that 1500 g of carbon was used.

[Comparative Example 2]
A sheet of Comparative Example 2 was produced in the same manner as Example 1 except that 300 g of carbon was used.

[Comparative Example 3]
Implemented except that instead of polymer A, 1000 g of polymer B (active chlorine acrylic rubber, trade name: PA402, manufactured by Nippon Mektron) was used and 500 g of carbon (trade name: FEF grade seast 116, manufactured by Tokai Carbon Co., Ltd.) was used. In the same manner as in Example 1, a sheet of Comparative Example 3 was produced.

[Comparative Example 4]
Further, as Comparative Example 4, silicon rubber (trade name: SRT-43-2, manufactured by SAKASE CHEMICAL INDUSTRY CO., LTD.) Was used to prepare a holding sheet having a thickness of 2 mm and a shape of 100 mm × 100 mm. The polymers and carbon compositions of Examples 1 to 3 and Comparative Examples 1 to 4 are shown in Table 1.

B. Adhesion test In the test method shown in FIG. 2, a stainless steel plate was used as the adherend 7, and the holding sheet 2 and the holding substrate 1 were bonded to the adherend 7. A tension gauge is attached to one end of the holding sheet 2, and as shown in FIG. 2, it is peeled off from one end where the tension gauge is attached and peeled off in a direction of 90 degrees with respect to the bonded direction, and the tension required for peeling is measured. did. The measurement results are also shown in the “Adhesion” item of Table 1.

C. Ion exchange membranes were affixed to the holding sheets of the contamination test examples and comparative examples, and left for 10 minutes in an atmosphere at 130 ° C. After leaving, the ion exchange membrane is peeled off from the holding sheet, and the ion exchange membrane surface secondary ion mass spectrum measurement is performed in the time-of-flight secondary ion mass spectrometry method (TOF-SIMS method) on the part where the holding sheet is attached. Then, qualitative and quantitative analysis of adhering elements by sheet pasting and drying was performed. The measurement results are also shown in the item “Si amount on electrolyte membrane” in Table 1. Table 2 shows the secondary ion mass spectrum measurement conditions by the TOF-SIMS method.

D. Crosslinking Acceleration Test An ion exchange membrane was attached to the holding sheets of Examples and Comparative Examples, and left in an atmosphere at 130 ° C. for 10 minutes. After leaving, the ion exchange membrane was peeled off from the holding sheet, and the portion where the holding sheet was attached was further left under an atmosphere of 120 ° C. for 200 hours. After that, the weight average molecular weight Mw / number average molecular weight Mn of the ion exchange membrane by means of gel permeation chromatography (GPC) by rubber attachment and drying is measured, and the degree of crosslinking is promoted in comparison with the ion exchange membrane without attachment of the holding sheet. The degree was calculated. The measurement results are also shown in the item “Crosslinking acceleration” in Table 1. Table 3 shows the GPC measurement conditions.

  Further, as shown in FIG. 1, each of the holding sheets of Examples and Comparative Examples was formed on an aluminum holding substrate 1. The solid polymer electrolyte membrane 3 is placed thereon, the cathode electrode catalyst layer paste 4 is applied and dried, the solid polymer electrolyte membrane 3 is peeled off from the holding sheet 2 and turned over, and the cathode electrode catalyst layer side is held on the holding sheet 2 was installed. Subsequently, the anode electrode catalyst layer paste 5 was applied and dried, and peeled off from the holding sheet 2 to obtain a membrane electrode composite.

  In the membrane electrode assembly using the holding sheets of Examples 1 to 3, since the holding sheet had an adhesive strength in an appropriate range (see the item “Adhesive strength” in Table 1), the solid polymer electrolyte membrane and No wrinkles or damage was observed in each electrode catalyst layer. Moreover, there was no Si contamination and heat durability was ensured. On the other hand, in the membrane electrode assembly using the holding sheet of Comparative Example 1, because there was too much carbon and the adhesive strength was insufficient, the adhesion of the solid polymer electrolyte membrane and the electrode catalyst layer was insufficient in the drying step, Habit has occurred. The membrane electrode composites using the holding sheets of Comparative Examples 2 and 3 have problems such that the carbon is too little and the adhesive strength is excessive, and the polymer electrolyte membrane is damaged at the time of peeling. Furthermore, in the membrane electrode assembly using the holding sheet of Comparative Example 4 using Si rubber and Comparative Example 3 using Polymer B, Si contamination was observed, and further, crosslinking promotion was observed.

  As mentioned above, although the effect of this invention was demonstrated by the Example, this invention is not limited only to the range of the said Example, As mentioned above, one electrode catalyst layer is formed by the 1st fixing process-the 1st drying process. It includes a form in which the other electrode catalyst layer is formed by another known method after the formation.

  The contact resistance between the electrode catalyst layer and the polymer electrolyte membrane is improved, the membrane electrode assembly is prevented from wrinkling and deformation, and the polymer electrolyte membrane is not contaminated by the holding sheet component, and the electrode catalyst layer has any shape It is possible to provide a polymer electrolyte fuel cell having

It is a schematic diagram which shows the manufacturing method of the membrane-electrode structure of this invention. It is a schematic diagram of the measuring method of the adhesive force of the holding sheet in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Holding base material 2 Holding sheet 3 Solid polymer electrolyte membrane
4 Electrode catalyst layer (paste)
5 Coating means 6 Electrode catalyst layer (paste)
7 adherend

Claims (7)

A fuel cell membrane electrode structure production holding sheet used when producing a fuel cell membrane electrode structure comprising electrode catalyst layers on both sides of a solid polymer electrolyte membrane,
The fuel cell membrane electrode structure production holding sheet is held by contacting the solid polymer electrolyte membrane or the electrode catalyst layer,
The fuel cell membrane electrode structure production holding sheet contains a polymer component in which —N— (CH ₂ ) ₆ —N— is crosslinked between the main chains and carbon,
The holding sheet for producing a membrane electrode structure for a fuel cell, wherein the carbon content is 36 to 53% by weight based on the total amount of the polymer component and carbon. The main chain of the polymer component is a carboxyl group-based acrylic rubber represented by the following chemical formula (1), and the —N— (CH ₂ ) ₆ —N— bridge is formed on the carboxyl group of the main chain. The holding sheet for producing a fuel cell membrane electrode structure according to claim 1.

(Y and Z are integers, R is an alkyl group) 3. The fuel cell membrane electrode structure production according to claim 1, wherein the —N— (CH ₂ ) ₆ —N— bridge in the carboxyl group of the main chain is formed by hexamethylenediamine. 4. Holding sheet. A method for producing a membrane electrode structure for a fuel cell in which a cathode electrode catalyst layer and an anode electrode catalyst layer are respectively formed on a solid polymer electrolyte membrane,
A first fixing step of installing the solid polymer electrolyte membrane on the fuel cell membrane electrode structure production holding sheet according to any one of claims 1 to 3;
A first coating step of coating one of a cathode electrode catalyst layer paste or an anode electrode catalyst layer paste on the solid polymer electrolyte membrane fixed;
A fuel cell membrane electrode structure manufacturing method comprising: a first removal step of removing the fuel cell membrane electrode structure manufacturing holding sheet from the solid polymer electrolyte membrane.   5. A first drying step of a composite comprising the electrode catalyst layer provided on the solid polymer electrolyte membrane between the first coating step and the first removal step. The manufacturing method of the membrane electrode structure for fuel cells as described in any one of. After the first removal step, a second fixing step of turning the composite upside down and placing the electrode catalyst layer side of the composite on the fuel cell membrane electrode structure production holding sheet;
A second application step of applying the other of the anode electrode catalyst layer paste or the cathode electrode catalyst layer paste to the solid polymer electrolyte membrane side of the fixed composite;
6. The method for producing a membrane electrode structure for a fuel cell according to claim 4 or 5, further comprising a second removing step of removing the sheet for producing the membrane electrode structure for a fuel cell from the composite.   The method for producing a membrane electrode structure for a fuel cell according to claim 6, further comprising a second drying step of the composite body between the second application step and the second removal step.

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