JP6201398B2 - Transfer sheet with mask film / base film, method for producing transfer sheet with mask film / base film, and method for producing catalyst layer sheet - Google Patents

Description

The present invention relates to a mask film base film with a transfer sheet, the mask film base film with a manufacturing method of the transfer sheet and manufacturing how the catalyst layer sheet.

  A solid polymer fuel cell using a polymer electrolyte membrane as an ion conductor is known as one of fuel cells that directly convert the reaction energy of a raw material gas into electric energy. The polymer electrolyte fuel cell is expected as an energy source for automobiles, railways, cogeneration systems, and the like because it has a shorter start-up time than other fuel cells and can operate at room temperature.

FIG. 1 is an exploded perspective view showing an example of the internal structure of a polymer electrolyte fuel cell. As shown in FIG. 1, a pair of electrode catalyst layers 52 </ b> A and 52 </ b> F are provided on both surfaces (upper surface and lower surface in the drawing) of the polymer electrolyte membrane 51 constituting the solid polymer fuel cell 50. Are formed so as to face each other. A gas diffusion layer 53A is formed on the electrode catalyst layer 52A, and a gas diffusion layer 53F is formed on the electrode catalyst layer 52F.
The polymer electrolyte membrane 51, the electrode catalyst layers 52A and 52F, and the gas diffusion layers 53A and 53F constitute a membrane electrode assembly (MEA) of the polymer electrolyte fuel cell 50. The separators 54A and 54F are arranged on the gas diffusion layers 53A and 53F so as to sandwich the membrane electrode assembly.

  The separators 54A and 54F have gas flow paths 55A and 55F, and these gas flow paths 55A and 55F face the gas diffusion layers 53A and 53F on both surfaces (the upper surface and the lower surface in the drawing) of the separators 54A and 54F. It is recessed on the side surface. Further, the separators 54A, 54F have cooling water passages 56A, 56F, and these cooling water passages 56A, 56F are recessed on the surface opposite to the gas flow paths 55A, 55F on both surfaces of the separators 54A, 54F. Yes.

  In the above-described polymer electrolyte fuel cell 50, cooling water is caused to flow through each of the pair of cooling water passages 56A and 56F, and for example, oxygen gas is caused to flow through one gas passage 55A, and the other gas passage 55F. For example, hydrogen gas is allowed to flow. And an electromotive force is produced | generated between a pair of gas diffusion layers 53A and 53F when oxygen gas and hydrogen gas advance electrode reaction in presence of a catalyst.

  As a method for producing such a membrane electrode assembly of the polymer electrolyte fuel cell 50, an electrode catalyst layer (hereinafter simply referred to as “catalyst layer”) is provided on a polymer electrolyte membrane (hereinafter also simply referred to as “electrolyte membrane”) 51. It is also referred to as “.” As one of the methods for forming 52A and 52F, there is a method using a catalyst layer sheet. In the method of forming the catalyst layers 52A and 52F on the electrolyte membrane 51 using the catalyst layer sheet, first, two catalyst layer sheets each having a catalyst layer formed on a transfer sheet are prepared. That is, a catalyst layer sheet in which the catalyst layer 52A is formed on the transfer sheet and a catalyst layer sheet in which the catalyst layer 52F is formed on the transfer sheet are prepared. And these catalyst layer sheets are arrange | positioned on both surfaces of the electrolyte membrane 51 so that the catalyst layers 52A and 52F may face the electrolyte membrane 51 side. Then, the catalyst layers 52A and 52F are transferred onto the electrolyte membrane 51 by applying a heat press or the like, and then the catalyst layers 52A and 52F are respectively formed on the electrolyte membrane 51 by peeling only the transfer sheet of the catalyst layer sheet. Form.

Conventionally, inexpensive resin films such as polyethylene terephthalate have been used for this transfer sheet. However, since the transfer sheet formed of this resin film has poor transferability, when the catalyst layers 52A and 52F are transferred to the electrolyte membrane 51 using the catalyst layer sheet in which the catalyst layers 52A and 52F are formed on the transfer sheet, the transfer sheet The catalyst layer residue was generated on the sheet, causing electrolyte membrane pinholes.
In order to improve this problem, a film in which a release layer is provided on a transfer sheet has been proposed.
The release layer is made of an olefin resin or a melamine resin. Patent Document 1 discloses a release film mainly composed of polyolefin.

However, since polyolefin has a low melting point, there is a problem that when the catalyst layers 52A and 52F are transferred to a release film composed of polyolefin at a high temperature of about 70 to 200 ° C., thermal wrinkles due to shrinkage of the polyolefin occur. It was.
As materials having high transferability, in addition to the above resins, ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer ( There are fluorine resins such as PFA) and polytetrafluoroethylene (PTFE).

JP 2006-150812 A

However, a film formed of a fluororesin having high transferability alone is soft and easily changes in dimensions. For this reason, there existed a problem in the handleability at the time of film conveyance in a manufacturing process, such as a wrinkle entering a film.
The present invention has been made in view of the above circumstances, and a membrane electrode assembly suitable for producing a membrane electrode assembly of a polymer electrolyte fuel cell and a mask capable of producing a polymer electrolyte fuel cell It is an object of the present invention to provide a transfer sheet with a film / base film.
Another object is to provide a manufacturing how the catalyst layer sheet formed by using the manufacturing method and the transfer sheet of the transfer sheet.

In order to solve the above-described problems, an aspect of the present invention provides a transfer sheet with a mask film and a base film for producing a membrane electrode assembly for a polymer electrolyte fuel cell, a transfer sheet, and one surface of the transfer sheet. Provided with a mask film having a desired opening, and a base film provided on a surface opposite to the mask film of the transfer sheet,
The mask film and the base film were each bonded to the transfer sheet via an adhesive layer, and the adhesive layer was measured at 180 ° peel strength (JIS-K) measured at a peel rate of 300 mm / min using a tensile tester. -6854-2: 1999) is in the range of 0.1 N / 25 mm or more and 2.0 N / 25 mm or less.

In one embodiment of the transfer sheet with a mask film / base film, the thickness of the adhesive layer may be in the range of 1 μm to 30 μm.
Moreover, the one aspect | mode of the said transfer film with a mask film and a base film WHEREIN: It is good also as forming the said mask film and the said base film with the film with the same dimensional change rate.

Moreover, the one aspect | mode of the said transfer film with a mask film and a base film WHEREIN: The said mask film and the said base film are good also as forming with the same material.
In one embodiment of the above transfer sheet with a mask film / base film, the transfer sheet may be an ethylene tetrafluoroethylene copolymer (ETFE), a tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or tetrafluoroperfluoro. It may be formed of a resin selected from an alkyl vinyl ether copolymer (PFA) and polytetrafluoroethylene (PTFE).

According to another aspect of the present invention, there is provided a method for producing the transfer sheet with a mask film / base film described above, wherein the opening is formed after the mask film is bonded to the transfer sheet. A method for producing a transfer sheet with a mask film and a base film.
Another aspect of the present invention is a method for producing the transfer sheet with a mask film / base film described above, wherein the opening is formed in the mask film, and then the mask film is bonded to the transfer sheet. A method for producing a transfer sheet with a mask film and a base film.

  Further, in another aspect of the present invention, a catalyst layer is formed on the transfer sheet in the opening provided in the transfer sheet with the mask film / base film described above, while leaving the catalyst layer on the transfer sheet, The method for producing a catalyst layer sheet, wherein the mask film, the base film, and the adhesive layer are peeled from the transfer sheet with the mask film / base film.

Another aspect of the present invention is a catalyst layer sheet produced by the method for producing a catalyst layer sheet described above, and comprising the catalyst layer formed on the transfer sheet.
Moreover, the other aspect of this invention is a polymer electrolyte fuel cell provided with the membrane electrode assembly manufactured using the catalyst layer sheet | seat of the said description.

  According to one embodiment of the present invention, the catalyst layer can be processed into various shapes by providing a mask film having a desired opening on one surface of the transfer sheet. In addition, by providing a base film made of the same material as the mask film on the surface opposite to the mask film of the transfer sheet, it is possible to suppress a change in the size of the transfer sheet in the drying process when forming the catalyst layer.

  Further, 180 ° peel strength (JIS−) was measured by measuring the adhesive layers formed between the mask film and the transfer sheet and between the base film and the transfer sheet using a tensile tester at a peel rate of 300 mm / min. K-6854-2: 1999) is within a range of 0.1 N / 25 mm or more and 2.0 N / 25 mm or less, so that the mask film and the base film can be easily peeled off from the transfer sheet after forming the catalyst layer. Is possible. For this reason, a good quality catalyst layer sheet can be provided. Moreover, a membrane electrode assembly suitable as a membrane electrode assembly of a polymer electrolyte fuel cell can be produced by using this good quality catalyst layer sheet.

It is a disassembled perspective view which shows the internal structure of the polymer electrolyte fuel cell which concerns on embodiment of this invention. It is the schematic which shows the structure of the transfer sheet (before and after catalyst layer formation) and catalyst layer sheet | seat with a mask film and base film which concern on embodiment of this invention.

  Hereinafter, an embodiment of a method for producing a membrane electrode assembly for a polymer electrolyte fuel cell and a polymer electrolyte fuel cell according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an exploded perspective view showing one embodiment of a polymer electrolyte fuel cell according to the present invention. In the following description, for the sake of convenience, the same reference numerals are given to the members described above, and redundant description thereof will be omitted. The present invention is not limited to the embodiments described below, and modifications such as design changes based on the knowledge of those skilled in the art can be added. Embodiments to which such modifications are added Are also included in the scope of the present invention.

  One embodiment of a transfer sheet with a mask film and a base film according to the present invention will be described with reference to FIG. FIG. 2A is a plan view showing the structure of a transfer sheet D10 with a mask film / base film for producing a membrane / electrode assembly of a polymer electrolyte fuel cell according to this embodiment. FIG. 2B is a cross-sectional view showing the structure of the transfer sheet D10 with a mask film / base film in a state where the catalyst layer 52A (52F) is not formed. FIG. 2C is a cross-sectional view showing the structure of the transfer sheet D20 with a mask film / base film in a state where the catalyst layer 52A (52F) is formed. As shown in FIGS. 2A to 2C, transfer sheets D10 and D20 with a mask film / base film are provided on one surface of the transfer sheet D2, and a mask film D1 having a desired opening, A base film D3 provided on the surface of the transfer sheet D2 opposite to the mask film D1 is provided via adhesive layers D4 and D5.

FIG. 2D shows the structure of the catalyst layer sheet D30 obtained by removing the mask film D2, the base film D3, and the adhesive layers D4 and D5 from the transfer sheet D20 with the mask film and base film shown in FIG. FIG.
The transfer sheet D2 is a sheet made of a material that can peel the catalyst layers 52A and 52F. For example, fluorine such as ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. System resin can be used as a material for the transfer sheet D2.

The thickness of the transfer sheet D2 can be appropriately selected according to the material so that the strength and heat resistance are appropriate, but usually a thickness of about 1 to 100 μm is preferably used.
Adhesive layers D4 and D5 are respectively formed on the surfaces of the mask film D1 and the base film D3 on the transfer sheet D2 side according to the present embodiment. In other words, the transfer sheet D2 is sandwiched between the mask film D1 and the base film D3 via the adhesive layers D4 and D5. Thus, the transfer sheet D10 with a mask film / base film is configured.

  The pressure-sensitive adhesive layers D4 and D5 according to the present embodiment have a 180 ° peel strength (JIS-K-6854-2: 1999) of 0.1 N / 25 mm or more measured using a tensile tester at a peel rate of 300 mm / min. It is desirable to be within a range of 0 N / 25 mm or less. If it is less than 0.1 N / 25 mm, the adhesion with the transfer sheet D2 is weak, and a gap is generated between the mask film D1 and the transfer sheet D2. In this case, the catalyst ink enters the gap when the catalyst layer is formed, and the linearity of the outer periphery of the catalyst layer is degraded. Further, if the thickness exceeds 2.0 N / 25 mm, the adhesion between the mask film D1 / base film D3 and the transfer sheet D2 is too strong, and therefore when the mask film D1 or the base film D3 is peeled off from the transfer sheet D2 after the catalyst layer is formed. In addition, the transfer sheet D2 is elongated, and a high-quality catalyst layer sheet D30 cannot be manufactured.

The thickness of the pressure-sensitive adhesive layers D4 and D5 according to this embodiment is preferably in the range of 0.1 μm to 30 μm. If it is less than 0.1 μm, uneven coating of the adhesive layers D4 and D5 will occur. Moreover, since the catalyst layers D4 and D5 are usually formed with a thickness of about 1 μm to 30 μm, a thickness exceeding 30 μm is not necessary.
The adhesive layers D4 and D5 according to the present embodiment are not particularly limited as long as they have a desired peel strength. For example, materials such as an epoxy resin, an acrylic resin, a urethane resin, a silicone resin, and rubber can be used as the adhesive layers D4 and D5.

The mask film D1 and the base film D3 are sheets made of a material having a small dimensional change rate. For example, an inexpensive polyester resin such as polyethylene terephthalate having excellent mechanical strength can be used as the material for the mask film D1 and the base film D3.
In order to form the catalyst layers 52A, 52F on the transfer sheet D10 with the mask film / base film, first, a catalyst ink is prepared by mixing the catalyst material-supporting carbon body, the polymer electrolyte and the solvent, and then the mask film / base film. There is a method of applying and drying the catalyst ink on the transfer sheet D10 with film.

As the polymer electrolyte of the catalyst ink, a polymer material having proton conductivity, for example, a fluorine-based polymer electrolyte or a hydrocarbon-based polymer electrolyte can be used. Examples of the fluoropolymer electrolyte include NAFION (registered trademark) manufactured by DuPont, FLEMION (registered trademark) manufactured by Asahi Glass Co., Ltd., ACIPLEX (registered trademark) manufactured by Asahi Kasei Co., Ltd., and GORE-SELECT (registered trademark) manufactured by Gore. Etc. Among these, in order to increase the output voltage of the polymer electrolyte fuel cell 50, it is desirable to use NAFION (registered trademark) manufactured by DuPont as a polymer electrolyte of the catalyst ink.
Examples of the hydrocarbon polymer electrolyte include electrolytes such as sulfonated polyetherketone, sulfonated polyethersulfone, sulfonated polyetherethersulfone, sulfonated polysulfide, and sulfonated polyphenylene.

  As the ink solvent, a solvent that does not erode the catalyst substance-supporting carbon body and the polymer electrolyte and dissolves the polymer electrolyte in a fluid state or disperses the polymer electrolyte as a fine gel is used. Is desirable. Such an ink solvent preferably contains a volatile organic solvent. Examples of the organic solvent contained in the ink solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, pentanol and other alcohols, acetone, and methyl ethyl ketone. , Pentanone, methyl isobutyl ketone, heptanone, cyclohexanone, methyl cyclohexanone, acetonyl acetone, diisobutyl ketone and other ketone solvents, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, anisole, methoxy toluene, dibutyl ether and other ether solvents, and other dimethylformamide , Dimethylacetamide, N-methylpyrrolidone, ethylene glycol, diethylene glycol, diacetone alcohol Le, 1-methoxy-2-propanol polar solvent such as, an organic solvent may be used which two or more are mixed among these solvents.

When a lower alcohol is used as the organic solvent, it is preferable to use the ink solvent as a mixed solvent with water in order to increase the ignition temperature of the ink solvent. Further, in order to increase the affinity with the polymer electrolyte, it is preferable that the ink solvent contains water to the extent that the polymer electrolyte is separated from the ink solvent to cause white turbidity or the polymer electrolyte does not gel. .
If the solid content of the catalyst substance-carrying carbon body or polymer electrolyte contained in the catalyst ink is excessive, the viscosity of the catalyst ink increases and cracks are likely to occur on the surfaces of the catalyst layers 52A and 52F. On the other hand, when the solid content is excessively low, the film formation speed of the catalyst layers 52A and 52F is decreased, and the productivity of the catalyst layers 52A and 52F is reduced. Therefore, the solid content of the catalyst ink is preferably in the range of 1% by mass to 50% by mass.

Incidentally, even in the case of a catalyst ink in which the contents of the catalyst material-supporting carbon body and the polymer electrolyte are equal to each other, the viscosity of the catalyst ink increases as the proportion of carbon particles increases, and conversely, the catalyst decreases as the proportion of carbon particles decreases. The viscosity of the ink is lowered. Therefore, the concentration of carbon particles contained in the catalyst ink is preferably in the range of 10% by mass to 80% by mass.
In addition, adjustment of the solid content of the catalyst ink, adjustment of the concentration of carbon particles in the solid content, and addition of a dispersant to the catalyst ink at the time of the dispersion treatment, the viscosity of the catalyst ink is set to a predetermined value. It is also possible to adjust to the value of. Moreover, it is preferable that the mass ratio of the polymer electrolyte with respect to a catalyst substance carrying | support carbon body exists in the range of 0.04 mass% or more and 3.00 mass% or less.

  In the catalyst ink coating step, the catalyst ink produced as described above is applied to the transfer sheet D10 with a mask film / base film. When the ink temperature of the catalyst ink is lower than 10 ° C., the viscosity of the catalyst ink increases, and it becomes difficult to obtain uniform catalyst layers 52A and 52F. If the ink temperature exceeds 50 ° C., the solvent of the catalyst ink volatilizes during coating.

  When the catalyst ink is applied onto the substrate (that is, the transfer sheet D2), the catalyst ink is applied onto the substrate using a doctor blade method, a dipping method, a screen printing method, a roll coating method, a spray method, or the like. be able to. Among these, spray methods such as a pressure spray method, an ultrasonic spray method, and an electrostatic spray method are preferable. According to such a method, since the catalyst ink hardly aggregates when the coated catalyst ink is dried, it is possible to obtain homogeneous catalyst layers 52A and 52F having a high porosity.

  The electrolyte membrane 51 is a polymer membrane having proton conductivity. As a material of the electrolyte membrane 51, for example, a fluorine-based polymer electrolyte or a hydrocarbon-based polymer electrolyte can be used. Examples of the fluoropolymer electrolyte include NAFION (registered trademark) manufactured by DuPont, FLEMION (registered trademark) manufactured by Asahi Glass Co., Ltd., ACIPLEX (registered trademark) manufactured by Asahi Kasei Co., Ltd., and GORE-SELECT (registered trademark) manufactured by Gore. Can be used. Among these, NAFION (registered trademark) manufactured by DuPont can be suitably used to increase the output voltage of the polymer electrolyte fuel cell 50.

  As the hydrocarbon polymer electrolyte, electrolytes such as sulfonated polyetherketone, sulfonated polyethersulfone, sulfonated polyetherethersulfone, sulfonated polysulfide, and sulfonated polyphenylene can be used. In order to secure adhesion between the catalyst layers 52A and 52F and the polymer electrolyte membrane 51, the catalyst layers 52A and 52F and the polymer electrolyte membrane 51 are preferably formed of the same material.

  The gas diffusion layers 53A and 53F are sheets made of a material having gas diffusibility and conductivity. For example, porous carbon materials such as carbon cloth, carbon paper, and nonwoven fabric can be used as the sheet material for the gas diffusion layers 53A and 53F. When the gas diffusion layers 53A and 53F are used as the base material, it is preferable to form a coating layer (not shown) in advance on the application surface to which the catalyst ink is applied.

  The eye-catching layer is a layer that prevents the catalyst ink from penetrating into the gas diffusion layers 53A and 53F. When the application amount of the catalyst ink is small, it is particularly preferable because the catalyst ink is deposited on the mesh layer and the mesh layer forms a three-phase interface. As such a sealing layer, for example, a layer obtained by sintering a fluorine resin solution in which carbon particles are dispersed at a temperature equal to or higher than the melting point of the fluorine resin can be used. Note that polytetrafluoroethylene (PTFE) or the like is used as the fluorine-based resin.

[Method for producing polymer electrolyte fuel cell]
In the manufacturing method of the polymer electrolyte fuel cell 50, first, the two catalyst layers 52A and 52F formed by the above method are arranged so as to face both surfaces of the electrolyte membrane 51.
Here, when the electrolyte membrane 51 is used as a base material on which the catalyst layers 52A and 52F are formed, the above arrangement is realized by forming the catalyst layers 52A and 52F on both surfaces of the electrolyte membrane 51. . When the gas diffusion layers 53A and 53F or the transfer sheet D2 are used as the base material, the above arrangement is realized by disposing the gas diffusion layers 53A and 53F or the transfer sheet D2 on both sides of the electrolyte membrane 51. Is done.

If the two catalyst layers 52A and 52F are arranged so as to face both surfaces of the polymer electrolyte membrane 51, then the two catalyst layers 52A and 52F and the polymer electrolyte membrane 51 are heated and pressurized. As a result, the catalyst layers 52A and 52F and the polymer electrolyte membrane 51 are joined to form one membrane electrode assembly.
When the polymer electrolyte membrane 51 is used as a substrate on which the catalyst layers 52A and 52F are formed, the gas diffusion layers 53A and 53F are disposed on both sides of the polymer electrolyte membrane 51, and then heated and heated. A membrane electrode assembly is formed by applying pressure. When the gas diffusion layers 53A and 53F are used as the base material, the polymer electrolyte membrane 51 is disposed between the gas diffusion layers 53A and 53F, and then these are heated and pressurized to form a membrane electrode assembly. It is formed.

  When the transfer sheet D2 is used as the substrate, the two catalyst layer sheets D30 on which the catalyst layers 52A and 52F are formed are arranged on both sides of the polymer electrolyte membrane 51 and then heated. The catalyst layers 52A and 52F are pressed against both surfaces of the polymer electrolyte membrane 51 by applying pressure. Then, after the transfer sheet D2 is peeled off from the catalyst layers 52A and 52F pressure-bonded to both surfaces of the polymer electrolyte membrane 51, the gas diffusion layers 53A and 53F are disposed on both surfaces of the polymer electrolyte membrane 51, and these are heated. By pressing together, one membrane electrode assembly can be obtained. Thereafter, the polymer electrolyte fuel cell 50 is manufactured by sandwiching both surfaces of the obtained membrane electrode assembly with a pair of separators 54A and 54F.

  For the separators 54A and 54F, for example, a carbon type or a metal type is used. Incidentally, the separators 54A and 54F may be configured integrally with the gas diffusion layers 53A and 53F. In the case where the separators 54A and 54F or the catalyst layers 52A and 52F have a gas diffusion function similar to the gas diffusion layers 53A and 53F, the gas diffusion layers 53A and 53F may be omitted.

  The manufacturing method of the transfer sheet D10 with a mask film / base film and the catalyst layer sheet D30 described above will be described with reference to the following specific examples and comparative examples. Moreover, the result of the peeling strength measurement of the mask film D1 / base film D3 and the transfer sheet D2 on the manufactured transfer sheet D10 with the mask film / base film will be described.

(Measurement of peel strength between mask film D1, base film D3 and transfer sheet D2)
A transfer sheet D10 with a mask film and a base film was prepared by arranging and laminating adhesive layers D4 and D5 respectively formed on the mask film D1 and the base film D3 on the front surface and the back surface of the transfer sheet D2. The transfer sheet D2 of the transfer sheet D10 with the mask film / base film is fixed, the end of the mask film D1 is sandwiched between the chucks of a tensile tester, and the peeling speed is 300 mm / min, 23 ° C., 50% RH, 180 °. The results of measuring the peel strength are shown in Table 1. In Table 1, a case where the shape of the outer periphery of the catalyst layer is good is indicated by “◯”, and a case where the shape of the outer periphery of the catalyst layer is poor (specifically, when the linearity is poor) is indicated by “x”. Show. Further, the case where the shape of the outer peripheral portion of the catalyst layer cannot be measured is indicated by “−”.

Example 1
A transfer sheet D10 with a mask film and a base film in which the thicknesses of the adhesive layers D4 and D5 formed on the mask film D1 and the base film D3 are 2.5 μm and the thicknesses of the mask film D1 and the base film D3 are 50 μm, respectively. Produced. And when the peeling strength measurement was implemented about the transfer sheet D10 with the mask film and base film, 180 degree peeling strength was 0.3 N / 25mm.

(Catalyst ink preparation method)
As a catalyst material-supporting carbon body, platinum-supporting carbon (trade name: TEC10E50E, manufactured by Tanaka Kikinzoku) and a solvent were kneaded using a planetary ball mill (trade name: P-7, manufactured by Fritsch Japan). At this time, the ball mill pot and balls were made of zirconia. Next, Nafion (registered trademark, manufactured by DuPont), which is a 20% by mass polymer electrolyte solution, was added as a polymer electrolyte, and kneaded again to prepare a catalyst ink.

(Catalyst layer sheet preparation method)
Next, the catalyst ink was applied to a transfer film D10 with a mask film / base film using polyethylene terephthalate with an adhesive on the mask film D1 and the base film D3, and tetrafluoroethylene as the transfer sheet D2. And the catalyst layer sheet | seat formed using the transfer sheet D10 with a mask film base film of Example 1 by drying the catalyst ink apply | coated on the transfer sheet D2 in the atmospheric condition whose temperature is 80 degreeC for 5 minutes. D30 was obtained. At this time, the thickness of the electrode catalyst layers 52A and 52F was adjusted so that the supported amount of the catalyst substance was 0.4 mg / cm ² . Observation of the outer peripheral shape of the produced catalyst layers 52A and 52F was good.

(Example 2)
A transfer sheet D10 with a mask film and a base film was prepared in the same manner as in Example 1 except that the thicknesses of the mask film D1 and the base film D3 were each 25 μm. The peel strength was 0.3 N / 25 mm, and the catalyst The shape of the outer periphery of the layer was good.

(Example 3)
A transfer sheet D10 with a mask film and a base film was prepared in the same manner as in Example 1 except that the thicknesses of the mask film D1 and the base film D3 were each 15 μm. The peel strength was 1.2 N / 25 mm, and the catalyst The shape of the outer periphery of the layer was good.

(Comparative Example 1)
Mask film as in Example 1, except that the thicknesses of the adhesive layers D4 and D5 of the mask film D1 and the base film D3 are 0.1 μm, respectively, and the film thicknesses of the mask film D1 and the base film D3 are 15 μm, respectively. -When the transfer sheet D10 with a base film was produced, the peel strength was as weak as 0.05 N / 25 mm, the catalyst ink entered the gap between the mask film D1 and the transfer sheet D2, and the outer shape of the catalyst layer was poorly linear. It was.

(Comparative Example 2)
The thicknesses of the adhesive layers D4 and D5 formed of an adhesive material having a lower adhesive strength than the adhesive material used in Example 1 were 7 μm, respectively, and the thicknesses of the mask film D1 and the base film D3 were 50 μm, respectively. A transfer sheet D10 with a mask film / base film was prepared in the same manner as in Example 1. As a result, the peel strength was as low as 0.07 N / 25 mm, and the catalyst ink entered the gap between the mask film D1 and the transfer sheet D2. The shape of the outer periphery was poor in linearity.

(Comparative Example 3)
The mask is the same as in Example 1 except that the thicknesses of the adhesive layers D4 and D5 formed on the mask film D1 and the base film D3 are 10 μm, respectively, and the film thicknesses of the mask film D1 and the base film D3 are 50 μm, respectively. When the transfer sheet D10 with a film / base film was produced, the peel strength was as strong as 3.0 N / 25 mm, and it was difficult to peel the mask film D1 from the transfer sheet D2, and the transfer sheet D2 was wrinkled.

As the above-mentioned result shows, a membrane electrode assembly suitable as a membrane electrode assembly of the polymer electrolyte fuel cell 50 can be manufactured by using the transfer sheet D10 with a mask film / base film according to this embodiment.
Therefore, this embodiment can be suitably used for a fuel cell using the polymer electrolyte membrane 51, a stationary cogeneration system, a fuel cell vehicle (FCV), and the like, and has great industrial utility value.

(Other embodiments)
In the above-described embodiment, the case where the adhesive layers D4 and D5 are respectively formed on one surface of the mask film D1 and the base film D3 has been described. However, the present invention is not limited to this. For example, after forming the adhesive layers D4 and D5 on both surfaces of the transfer sheet D2, the mask film D1 and the base film D3 may be formed on the adhesive layers D4 and D5, respectively. Even the transfer film D10 with the mask film / base film formed in this way has the same effects as the above-described effects.

DESCRIPTION OF SYMBOLS 50 ... Solid polymer fuel cell 51 ... Polymer electrolyte membrane 52A, 52F ... Electrode catalyst layer 53A, 53F ... Gas diffusion layer 54A, 54F ... Separator 55A, 55F ... Gas flow path 56A, 56F ... Cooling water path D1 ... Mask Film D2 ... Transfer sheet D3 ... Base film D4, D5 ... Adhesive layer D10 ... Transfer sheet with mask film / base film (before catalyst layer formation)
D20 ... Transfer sheet with mask film / base film (after catalyst layer formation)
D30 ... Catalyst layer sheet

Claims (8)

A transfer sheet with a mask film and a base film for producing a membrane electrode assembly for a polymer electrolyte fuel cell, a transfer sheet, a mask film having a desired opening provided on one surface of the transfer sheet, A base film provided on the surface of the transfer sheet opposite to the mask film; and
The mask film and the base film are each bonded to the transfer sheet via an adhesive layer,
180 degree peeling strength (JIS-K-6854-2: 1999) which measured the said adhesion layer at the peeling speed of 300 mm / min using the tensile tester is in the range of 0.1N / 25mm or more and 2.0N / 25mm or less. A transfer sheet with a mask film and a base film, characterized in that   The transfer sheet with a mask film / base film according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness in the range of 1 μm to 30 μm.   The transfer sheet with a mask film / base film according to claim 1, wherein the mask film and the base film are formed of films having the same dimensional change rate.   The transfer sheet with a mask film / base film according to any one of claims 1 to 3, wherein the mask film and the base film are formed of the same material.   The transfer sheet is made of ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), and polytetrafluoroethylene (PTFE). The transfer sheet with a mask film / base film according to any one of claims 1 to 4, wherein the transfer sheet is formed of a resin selected from the group consisting of: A method for producing a transfer sheet with a mask film and a base film according to any one of claims 1 to 5,
A method for producing a transfer sheet with a mask film and a base film, wherein the opening is formed after the mask film is bonded to the transfer sheet. A method for producing a transfer sheet with a mask film and a base film according to any one of claims 1 to 5,
A method for producing a transfer sheet with a mask film and a base film, comprising: forming the opening in the mask film; and bonding the mask film to the transfer sheet.   A catalyst layer is formed on the transfer sheet in the opening provided in the transfer sheet with a mask film and a base film according to any one of claims 1 to 5, and the catalyst layer is left on the transfer sheet. Meanwhile, the method for producing a catalyst layer sheet, comprising peeling off the mask film, the base film, and the adhesive layer from the mask film / base film-attached transfer sheet.

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