JP2008251376A - Transfer sheet for manufacturing electrolyte membrane-electrode assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer sheet for manufacturing an electrolyte membrane-electrode assembly capable of completely transferring a catalyst layer without almost peeling off a peeling-off layer from the transfer sheet. <P>SOLUTION: The transfer sheet is a transfer sheet for manufacturing an electrolyte membrane-electrode assembly wherein the peeling-off layer and catalyst layer are formed on at least one side of a base material sheet, and the peeling-off layer is formed of a resin with a melting point of 100°C or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transfer sheet for producing an electrode-electrolyte membrane assembly.

  A fuel cell is a system that generates electricity by an electrochemical reaction between hydrogen and oxygen by arranging catalyst layers on both sides of an electrolyte membrane, and only water is generated during power generation. Unlike conventional internal combustion engines, fuel cells are attracting attention as a next-generation clean energy system because they do not generate environmentally harmful gases such as carbon dioxide.

  A polymer electrolyte fuel cell uses a hydrogen ion conductive polymer electrolyte membrane as an electrolyte membrane layer, a catalyst layer is arranged on both sides thereof, an electrode substrate is arranged on both sides thereof, and this is further sandwiched between separators. Has a structure. A catalyst layer is arranged on both sides of the electrolyte membrane layer, and then an electrode substrate is arranged on both sides thereof (that is, electrode substrate / catalyst layer / electrolyte membrane / catalyst layer / electrode substrate layer configuration) It is called an electrode-electrolyte membrane assembly.

  Various methods have been proposed to date for producing catalyst layers for fuel cells and the like. Among these, the transfer method of transferring the catalyst layer once produced using another base material to the electrolyte membrane is easy to form the catalyst layer, and since there is little adverse effect on the electrolyte membrane and the gas diffusion layer, It is advantageous.

  For example, Patent Document 1 discloses a transfer sheet for producing an electrode-electrolyte membrane assembly, in which a catalyst layer is formed on at least one surface of a substrate via a release layer. The release layer is a layer necessary for completely transferring the catalyst layer from the transfer sheet.

  However, when the catalyst layer is transferred using the transfer sheet, it is inevitable that the release layer is transferred simultaneously with the catalyst layer. The release layer does not have electron and ion conductivity. Therefore, if the release layer adheres to the catalyst layer, the electron and ion conduction is hindered, and the fuel cell performance is deteriorated. In addition, if the release layer remains on the catalyst layer, gas diffusibility is lowered, which also contributes to a decrease in fuel cell performance.

For this reason, there is a demand for the development of a transfer sheet for producing an electrode-electrolyte membrane assembly, in which the release layer hardly peels from the transfer sheet and the catalyst layer can be completely transferred.
JP 2003-25794 A

  An object of the present invention is to provide a transfer sheet for producing an electrode-electrolyte membrane assembly free from the above drawbacks.

  The present inventor has intensively studied to solve the above problems. As a result, when forming a peeling layer and a catalyst layer in at least one surface of a base material, it discovered that the said subject could be solved by pattern-forming a peeling layer. The present invention has been completed based on such findings.

The present invention provides the transfer sheet according to item 1 and item 2 below.
Item 1. A transfer sheet for producing an electrode-electrolyte membrane assembly in which a release layer and a catalyst layer are formed on at least one side of a base sheet, wherein the release layer is made of a resin having a melting point of 100 ° C. or more, and the release layer A transfer sheet in which a pattern is formed on a substrate sheet.
Item 2. Item 2. The transfer sheet according to Item 1, wherein the release layer is formed at an end of the substrate sheet, and the catalyst layer is formed on the surface of the substrate sheet and the release layer other than the release layer formed on the substrate sheet.

Transfer sheet for producing electrode-electrolyte membrane assembly The transfer sheet for producing an electrode-electrolyte membrane assembly of the present invention is formed by forming a catalyst layer on at least one surface of a substrate sheet via a release layer.

  In the present invention, the release layer is patterned on the substrate sheet. An example of the peeling layer patterned on the base material sheet is shown in FIGS. 1 to 3, a cross-sectional view is shown above and a plan view is shown below.

  In the present invention, the catalyst layer is formed on the patterned release layer and on the substrate sheet on which the release layer is not formed. An example of the transfer sheet of the present invention is shown in FIG. FIG. 4 is a cross-sectional view of the transfer sheet of the present invention.

  In the transfer sheet of the present invention, the release layer is formed at the end of the base sheet, and the catalyst layer is formed on the surface of the base sheet and the release layer other than the release layer formed on the base sheet. preferable.

As the base sheet , for example, polyimide, polyethylene terephthalate, polyparvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyether ether ketone, polyetherimide, polyarylate, polyethylene naphthalate Examples thereof include polymer films such as phthalate.

  In addition, heat resistance of ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. Fluorine resin can also be used.

  Further, the base sheet may be paper such as art paper, coated paper, coated paper such as lightweight coated paper, non-coated paper such as notebook paper, copy paper, etc. in addition to the polymer film.

  The thickness of the base sheet is usually about 6 to 100 μm, preferably about 6 to 30 μm, and more preferably about 6 to 15 μm from the viewpoints of handleability and economy.

  Therefore, as a base material sheet, an inexpensive and easily available polymer film is preferable, and polyethylene terephthalate or the like is more preferable.

Release Layer In the present invention, the release layer is made of a resin having a melting point of 100 ° C. or higher.

  Examples of the resin having a melting point of 100 ° C. or higher include fluororesin, silicone resin, melamine resin, polyethersulfone, polyamide resin (nylon 66), polyimide resin, polyester resin, (meth) acrylic resin, acrylic polyol resin, and cyclic olefin. Resin, norbornene resin, polycarbonate resin, polyarylate resin, polyamideimide resin, polyetherimide resin, polysulfone resin and the like.

  Specific examples of the fluororesin include Fluon manufactured by Asahi Glass Co., Dinion manufactured by Sumitomo 3M Co., Marvel Coat manufactured by Hishoe Chemical Co., and Daiel Latex manufactured by Daikin. Specific examples of the silicone resin include silicone RTV rubber manufactured by Shin-Etsu Chemical Co., Ltd., grease mate paste manufactured by Kure Kogyo Co., Ltd., and Tospearl manufactured by Momentive Performance Materials Japan. Specific examples of the melamine resin include Nicaret manufactured by Nippon Carbide Industries. Specific examples of the polyethersulfone resin include Sumitomo Chemical manufactured by Sumitomo Chemical. Specific examples of the polyamide resin include VISTAMID manufactured by Daicel Degussa. Specific examples of the polyimide resin include HL-P500 manufactured by Hitachi Chemical Co., Ltd., Photo Nice manufactured by Toray Industries, Inc., CT series manufactured by Kyocera Corporation, S. Examples include Payer ML manufactured by T Company. Specific examples of the polyester resin include Almatex manufactured by Mitsui Chemicals, Byron manufactured by Toyobo, and Vylonal manufactured by Toyobo. Specific examples of the (meth) acrylic resin include ray queen manufactured by Mitsubishi Rayon Co., and dialnal manufactured by Mitsubishi Rayon Co., Ltd. Specific examples of the acrylic polyol resin include Thermolac SU-100A manufactured by Soken Chemical Co., Ltd. Specific examples of the cyclic olefin-based resin include an appel made by Mitsui Chemicals. Specific examples of the norbornene-based resin include Arton G manufactured by JSR Corporation. Specific examples of the polycarbonate resin include panlite manufactured by Teijin Chemicals Ltd. Specific examples of the polyarylate resin include U polymer manufactured by Unitika Ltd. Specific examples of the polyamideimide resin include HL-P200 manufactured by Hitachi Chemical Co., Ltd., Viromax manufactured by Toyobo Co., Ltd., and the like. Specific examples of the polyetherimide resin include ULTEM manufactured by Nippon Polypenco.

  Particularly preferred resins are fluororesins (Fluon manufactured by Asahi Kasei Co., Ltd.) and Arton G manufactured by norbornene resin JSR.

  The melting point of the resin was measured using DSC (differential scanning calorimetry) according to JIS K7121.

  The thickness of the release layer is usually about 0.01 to 1000 μm, preferably about 0.1 to 500 μm, more preferably about 0.2 to 20 μm.

  In patterning the release layer on the substrate sheet, the resin is preferably applied according to a known method so as to have a desired thickness. In order to facilitate the coating operation, the resin may be dissolved or dispersed in an appropriate solvent and used in the form of a solution or an emulsion. The coating method is not particularly limited, and for example, general methods such as knife coater, bar coater, spray coater, dip coater, spin coater, roll coater, die coater, curtain coater, and screen printing can be applied. .

Catalyst layer The catalyst layer is a known one.

  The catalyst layer contains carbon particles supporting catalyst particles and a hydrogen ion conductive polymer electrolyte.

  Examples of the catalyst particles include platinum and platinum compounds. Examples of the platinum compound include an alloy of platinum and at least one metal selected from the group consisting of ruthenium, palladium, nickel, molybdenum, iridium, iron and the like.

  Examples of the hydrogen ion conductive polymer electrolyte include perfluorosulfonic acid-based fluorine ion exchange resins.

  In forming the catalyst layer on the release layer and the base sheet, the carbon particles supporting the catalyst particles and the hydrogen ion conductive polymer electrolyte are mixed and dispersed in an appropriate solvent to form a paste. The paste is preferably applied onto the release layer and the base sheet according to a known method so that the catalyst layer to be formed has a desired thickness.

  Examples of the solvent include various alcohols, various ethers, various dialkyl sulfoxides, water, or a mixture thereof.

  The method for applying the paste is not particularly limited. For example, a general method such as a knife coater, bar coater, spray coater, dip coater, spin coater, roll coater, die coater, curtain coater, or screen printing can be used. Applicable.

  After applying such paste, the catalyst layer is formed by drying. The drying temperature is desirably equal to or lower than the melting point of the resin constituting the release layer, and is usually about 40 to 100 ° C, preferably about 60 to 80 ° C. Although depending on the drying temperature, the drying time is usually about 5 minutes to 2 hours, preferably about 30 minutes to 1 hour.

  The thickness of the catalyst layer is usually about 10 to 50 μm, preferably about 15 to 30 μm.

Catalyst layer-electrolyte membrane laminate The electrolyte membrane (catalyst layer-electrolyte membrane laminate) on which the catalyst layer is laminated is, for example, arranged such that the transfer sheet is disposed so that the catalyst layer surface of the transfer sheet of the present invention faces the electrolyte membrane surface. After pressing, the substrate sheet of the transfer sheet is peeled off. By repeating this operation twice, a catalyst layer-electrolyte membrane laminate in which the catalyst layer surface is laminated on both surfaces of the electrolyte membrane is produced.

  In consideration of workability, the catalyst layer surface is preferably laminated on both surfaces of the electrolyte membrane at the same time. In this case, for example, the transfer sheet may be disposed such that the catalyst layer surface of the transfer sheet of the present invention faces both surfaces of the electrolyte membrane, and after pressing, the substrate sheet of the transfer sheet may be peeled off.

  The electrolyte membrane used is a known one. The thickness of the electrolyte membrane is usually about 20 to 250 μm, preferably about 20 to 80 μm. Specific examples of electrolyte membranes include “Nafion” membrane manufactured by DuPont, “Flemion” membrane manufactured by Asahi Glass Co., Ltd., “Aciplex” membrane manufactured by Asahi Kasei Co., Ltd., and “Gore Select” manufactured by Gore. Examples include membranes.

  The pressure level is usually about 0.5 to 20 Mpa, preferably about 1 to 10 Mpa in order to avoid transfer defects. Further, it is preferable to heat the pressure surface during this pressure operation in order to avoid transfer failure. The heating temperature is usually 200 ° C. or lower, preferably 150 ° C. or lower in order to avoid breakage, modification, etc. of the electrolyte membrane.

Electrode-electrolyte membrane assembly An electrode-electrolyte membrane assembly is produced by placing an electrode substrate on both sides of a catalyst layer-electrolyte membrane laminate and applying pressure.

  The electrode base material is well known, and various electrode base materials constituting a fuel electrode and an air electrode can be used.

  The pressure level is usually about 0.1 to 100 Mpa, preferably about 5 to 15 Mpa. It is preferable to heat at the time of this pressurization operation, and heating temperature may be about 120-150 degreeC normally.

  In the transfer sheet for producing an electrode-electrolyte membrane assembly of the present invention, the release layer hardly peels off from the transfer sheet, and the catalyst layer can be completely transferred.

  Therefore, if the transfer sheet of the present invention is used, a high-quality fuel cell having excellent battery performance can be produced.

  Further, the transfer sheet of the present invention has the following advantages.

  Since the release layer is provided, it becomes a trigger for peeling the base sheet of the transfer sheet from the electrolyte membrane at the time of transfer, and it becomes easy to peel off.

  Since the release layer is patterned only at the end of the catalyst layer, the release layer does not cover the entire surface of the catalyst layer when the catalyst layer is transferred.

  When the transfer sheet is cut, the release layer is a guide for cutting.

  The present invention will be further clarified by the following examples and comparative examples.

Example 1
Platinum ruthenium-supported carbon (Pt: 27.2% by weight, Ru: 28.7% by weight) (Tanaka Kikinzoku Co., Ltd., TEC62E58) 10 parts by weight and 5% by weight electrolyte solution (manufactured by DuPont, DE-520, solvent) : 1-propanol / water = 1/1 (weight ratio)) was added to 100 parts by weight of isopropyl alcohol and 2 parts by weight of propylene glycol, and mixed and dispersed to prepare a catalyst layer forming paste.

  As the release layer forming paste, a dispersion type (commercially available) of fluororesin (Fluon, manufactured by Asahi Glass Co., Ltd.) was used.

  Next, on the PET film (Toyobo Co., Ltd., E5100, thickness 25 μm, width 95 mm), a release layer forming paste is applied by gravure printing at a thickness of about 0.5 to 1 μm, 10.5 mm from both ends of the PET film. Worked. The release layer forming paste was dried, and the release layer was patterned on the PET film as shown in FIG.

  On the release layer and on the PET film on which no release layer is formed, the prepared paste for forming a catalyst is applied with a doctor blade to a thickness of 50 μm, and this is dried at 50 ° C. for 12 hours in an air atmosphere. A catalyst layer was formed.

  The produced catalyst layer transfer sheet was completed by earing at a position 10 mm from both ends of the PET film.

Example 2
The same catalyst layer forming paste and release layer forming paste as in Example 1 were used.

  The print pattern shape of the release layer is different. On the PET film (Toyobo Co., Ltd., E5100, thickness 25 μm, width 95 mm), the release layer forming paste by gravure printing is 5.5 mm from the inside of the PET film 5 mm inside. The width line pattern was applied with a thickness of about 0.5 to 1 μm. The release layer forming paste was dried, and a release layer was patterned on the PET film as shown in FIG.

  A catalyst layer forming paste was applied to a thickness of 50 μm with a doctor blade on a release layer and a PET film on which no release layer was formed, and this was dried at 50 ° C. in an air atmosphere for 12 hours to obtain a catalyst layer. Formed.

  The produced catalyst layer transfer sheet was completed by earing at a position 10 mm from both ends of the PET film.

Example 3
The same catalyst layer forming paste and release layer forming paste as in Example 1 were used.

  On a PET film (Toyobo Co., Ltd., E5100, thickness 25 μm, width 95 mm), a paste for forming a release layer by gravure printing is used as a reference 5 mm from the both ends of the PET film, a 5.5 mm wide line, and the film flow direction The film was applied at a thickness of about 0.5 to 1 μm so that a desired film length was obtained by separating a line having a width of 5.5 mm perpendicularly to the substrate by 74 mm. The release layer forming paste was dried, and the release layer was patterned on the PET film as shown in FIG.

  A catalyst layer forming paste was applied to a thickness of 50 μm with a doctor blade on a release layer and a PET film on which no release layer was formed, and this was dried at 50 ° C. in an air atmosphere for 12 hours to obtain a catalyst layer. Formed.

  The produced catalyst layer transfer sheet was completed by earing at a position 10 mm from both ends of the PET film.

Example 4
The same catalyst layer forming paste as in Example 1 was used.

  For the release layer forming paste, norbornene resin (manufactured by JSR, trade name: Arton G), acrylic polyol resin (manufactured by Soken Chemicals, trade name: Thermolac SU-100A) and toluene / methyl ethyl ketone (weight ratio 7/3) ) At a ratio of 40/10/50 (weight ratio).

  Next, on the PET film (Toyobo Co., Ltd., E5100, thickness 25 μm, width 95 mm), a release layer forming paste is applied by gravure printing at a thickness of about 0.5 to 1 μm, 10.5 mm from both ends of the PET film. Worked. The release layer forming paste was dried, and the release layer was patterned on the PET film as shown in FIG.

  On the release layer and on the PET film on which no release layer is formed, the prepared paste for forming a catalyst is applied with a doctor blade to a thickness of 50 μm, and this is dried at 50 ° C. for 12 hours in an air atmosphere. A catalyst layer was formed.

  The produced catalyst layer transfer sheet was completed by earing at a position 10 mm from both ends of the PET film.

Comparative Example 1
The same catalyst layer forming paste as in Example 1 was used.

  On a PET film (Toyobo Co., Ltd., E5100, thickness 25 μm, width 95 mm), a catalyst layer forming paste was applied with a doctor blade to a thickness of 50 μm, and this was dried at 50 ° C. in air for 12 hours. A catalyst layer was formed.

  The produced catalyst layer transfer sheet was completed by earing at a position 10 mm from both ends of the PET film.

Comparative Example 2
The same catalyst layer forming paste and release layer forming paste as in Example 1 were used.

  On a PET film (Toyobo Co., Ltd., E5100, thickness 25 μm, width 95 mm), a release layer forming paste was applied to the entire surface with a thickness of about 0.5 to 1 μm. The release layer forming paste was dried to form a release layer on the PET film.

  On the release layer, a catalyst layer forming paste was applied with a doctor blade so as to have a thickness of 50 μm, and this was dried in an air atmosphere at 50 ° C. for 12 hours to form a catalyst layer.

  The produced catalyst layer transfer sheet was completed by earing at a position 10 mm from both ends of the PET film.

  The transferability of the transfer sheets prepared in Examples 1 to 4 and Comparative Examples 1 and 2 was evaluated. The results are shown in the table below.

FIG. 1 is a drawing showing an example in which a release layer is patterned on a substrate sheet. FIG. 2 is a drawing showing an example in which a release layer is patterned on a substrate sheet. FIG. 3 is a drawing showing an example in which a release layer is patterned on a substrate sheet. FIG. 4 is a cross-sectional view showing an example of the transfer sheet of the present invention.

Claims (2)

A transfer sheet for producing an electrode-electrolyte membrane assembly, in which a release layer and a catalyst layer are formed on at least one side of a substrate sheet,
The release layer is made of a resin having a melting point of 100 ° C. or higher,
The release layer is patterned on the substrate sheet,
Transfer sheet.   The transfer sheet according to claim 1, wherein the release layer is formed at an end of the base sheet, and the catalyst layer is formed on the surface of the base sheet and the release layer other than the release layer formed on the base sheet. .

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