JP6997935B2 - Manufacturing method of separator for fuel cell - Google Patents

Description

The present invention relates to a method for manufacturing a separator for a fuel cell.

A fuel cell is a device that extracts the generated Gibbs energy of water generated when hydrogen is electrochemically oxidized as electrical energy.

In general, this type of fuel cell is put into practical use by stacking a plurality of fuel cell cells to form a stack. A fuel cell usually has an electrolyte electrode junction in which an anode electrode that supplies fuel gas to one side of an electrolyte and a cathode electrode that supplies an oxidizing agent gas to the other side are joined, and a gas flow path, a refrigerant liquid flow path, or the like is used. It is sandwiched by a pair of formed separators.

In a fuel cell having such a structure, it is necessary to prevent mixing of the fuel gas and the oxidant gas, leakage of each gas or a refrigerant, and the like. Therefore, an adhesive seal member is often provided at a portion where airtightness and liquidtightness are required, such as between the separator and the electrolyte, and between the separators.

For example, as a method for manufacturing a separator, a method using an adhesive containing a thermosetting main component such as an epoxy-based adhesive (Patent Documents 1 and 2) as an adhesive used for a joint with a metal layer and an adherend layer. Has been invented.
Epoxy adhesives need to be cured, and it takes time to complete the curing, and during curing, curing defects may occur due to the effects of impurities, etc., so be extremely careful when handling the work environment. I had to do it.
Therefore, in Patent Document 3, a thermoplastic hot melt adhesive containing an olefin-based thermoplastic resin is used as an adhesive to heat and bond the metal layer. However, there are problems such as weak adhesive strength.

Japanese Unexamined Patent Publication No. 2005-129343 Japanese Unexamined Patent Publication No. 7-249417 Japanese Unexamined Patent Publication No. 2007-188718

In view of the above problems, an object of the present invention is to bond an adherend layer to a laminate formed by laminating a metal layer and a thermoplastic hot melt adhesive layer containing a resin having an acid value of 1 to 200 mgKOH / g in this order. In the method of manufacturing a separator for a fuel cell, an electromagnetic induction heating method is used during the bonding step to obtain a separator for a fuel cell having adhesion in a short time and good adhesive strength.

As a result of repeated sharp research, the present inventors have found a fuel cell separator and a method for manufacturing a fuel cell separator that solves the problem.

That is, the present invention is a method for manufacturing a separator for a fuel cell, which comprises a step of adhering a laminate formed by laminating a metal layer and a thermoplastic hot melt adhesive layer in this order and an adherend layer. The present invention relates to a method for producing a separator for a fuel cell, wherein the step includes a step of heating a metal layer by electromagnetic induction heating, and the thermoplastic hot melt adhesive contains a resin having an acid value of 1 to 200 mgKOH / g. ..

The present invention also relates to a method for producing the separator for a fuel cell, wherein the resin contains a copolymer of ethylene and (meth) acrylic acid and / or a polyolefin.

The present invention also relates to a method for producing the separator for a fuel cell, wherein the resin contains a copolymer of an acid-modified styrene-based aromatic hydrocarbon and a conjugated diene block, or a hydrogenated product thereof.

The present invention also relates to a method for manufacturing the separator for a fuel cell, which is characterized in that the melting point of the resin is 70 to 250 ° C.

The present invention also relates to a method for producing the fuel cell separator, wherein the thermoplastic hot melt adhesive contains a component soluble in xylene at 25 ° C., but the content thereof is less than 5% by weight.

The present invention also relates to a method for manufacturing a fuel cell separator, wherein the adherend layer is a metal layer.

The present invention also relates to a method for manufacturing a separator for a fuel cell, which is characterized in that the time required for a step of heating a metal layer by electromagnetic induction heating is within 5 seconds.

The present invention also relates to a method for manufacturing a fuel cell, which comprises a method for manufacturing the separator for a fuel cell.

As described above, according to the method for manufacturing a fuel cell separator according to the present invention, the bonding time of a conductive layer such as a carbon or metal layer in the coolant flow path of the separator is short, and the heat resistance is good. Adhesion can be done.

A typical embodiment of the fuel cell of the present invention is shown. A typical embodiment of the fuel cell of the present invention is shown. A typical embodiment of the fuel cell of the present invention is shown.

Hereinafter, the method for producing the separator of the present invention will be described.

[Fuel cell structure]
The structure of the fuel cell of the present invention will be described in detail. FIG. 1 shows a cross-sectional view of the fuel cell 1. The fuel cell 1 includes a power generator 18 and a separator 11. The power generator 18 is composed of an electrolyte film 71, an anode layer 41, a cathode layer 42, and a gas diffusion layer 31 and 32, and the separator 11 is a metal layer 13, an adherend layer 15 and a cooling layer bonded by a thermoplastic hot melt adhesive layer 12. It consists of a liquid flow path.

The electrolyte membrane 71 has a function of moving hydrogen ions generated in the anode layer 41 to the cathode layer 42. As the material of the electrolyte membrane 71, a chemically stable fluororesin resin, for example, a perfluorocarbonic acid (nafillon) resin membrane is used.

The anode layer 41 and the cathode layer 42 have a function of promoting an oxidation reaction of hydrogen on the anode electrode side and a reduction reaction of oxygen on the cathode electrode side. The catalyst is generally used in the form of particles, which are attached to the carrier of the catalyst in order to increase the area of the electrode to be reacted. As the catalyst, platinum or the like, which is a platinum group element having a smaller activation overvoltage for the oxidation reaction of hydrogen and the reduction reaction of oxygen, is used. As the carrier of the catalyst, a carbon material, for example, carbon black or the like is used.

The gas diffusion layers 31 and 32 have a function of diffusing hydrogen gas, which is a fuel gas, and air, which is an oxidant gas, to the anode layer 41 and the cathode layer 42, and a function of moving electrons. .. For the gas diffusion layers 31 and 32, carbon fiber woven fabric, carbon paper, or the like, which is a material having electrical conductivity, is used.

[Separator]
The separator 11 of the present invention is laminated on the power generation body 18 and has a function of separating the fuel gas and the oxidant gas in the adjacent fuel cell. The separator 11 is formed by adhering to a metal layer 13 and an adherend layer 15 formed in an uneven shape with an electrically conductive material. By making the electric conductive layer uneven, gas flow paths 17 and 19 through which fuel gas or oxidation gas flows, and a cooling liquid LLC (long-Life-Coolant) containing ethylene glycol or the like are used, and the flowing cooling liquid is used. A flow path 14 is formed.

The separator 11 of the fuel cell having such a structure needs to be cooled with a coolant in order to prevent heat generated during power generation or the like. Therefore, a cooling liquid flow path 14 is formed in order to improve the cooling efficiency in the separator and circulate the cooling liquid. In the separator 11, the metal layer 13 and the adherend layer 15 are formed by the thermoplastic hot melt adhesive layer 12. It is made by gluing.

[Metal layer]
The metal layer 13 of the separator of the present invention is preferably formed of a conductive and acid-resistant titanium (Ti), titanium alloy, gold (Au), platinum (Pt), SUS316, SUS304 stainless steel or the like.
The thickness of the metal layer 13 is preferably 10 to 500 μm, more preferably 50 to 300 μm. If the thickness of the metal layer is less than 10 μm, cooling water leaks due to fatigue of the metal layer, and if it is 500 μm or more, the weight of the cell becomes heavy, which is not realistic.

[Applied layer]
The adherend layer 15 is made of a metal, ceramics, a polymer, or the like, and does not necessarily have to be a conductor.

[Thermoplastic hot melt adhesive layer]
The thermoplastic hot-melt adhesive forming the thermoplastic hot-melt adhesive layer of the present invention is in a molten state when heated, and is solidified by cooling and adheres to the adherend layer.
(Resin with acid value of 1 to 200 mgKOH / g)
The thermoplastic hot melt adhesive is characterized by containing a resin having an acid value of 1 to 200 mgKOH / g.
The acid value of the present invention is the number of mg of potassium hydroxide required to neutralize 1 g of free fatty acid.
The acid value of the resin contained in the thermoplastic hot melt adhesive of the present invention is characterized by being 1 to 200 mgKOH / g, and more preferably 1 to 160 mgKOH / g. If the acid value of the resin is less than 1 mgKOH / g, the adhesive strength with the metal is weak and it cannot be used. The force is greatly reduced.
The resins contained in the thermoplastic hot melt adhesive include acid-modified olefins, (meth) acrylic acid copolymers, acid-modified styrene-based aromatic hydrocarbons, styrene-butylene-styrene block polymer (SBS), and styrene-ethylene. An acid-modified product of a copolymer with a conjugated diene block such as propylene-styrene block polymer (SEPS), styrene-isoprene-styrene block polymer (SIS), styrene-butylene butadiene-styrene block polymer (SBBS), or an acid-modified product thereof. Examples include polymer, rosin-based resin, and the like.

(Melting point of resin with acid value of 1 to 200 mgKOH / g)
The melting point of the present invention is based on the differential scanning calorimetry (DSC: heat flux) in JIS K 7121.
The melting point of the resin having an acid value of 1 to 200 mgKOH / g contained in the thermoplastic hot melt adhesive of the present invention is preferably 70 to 250 ° C, more preferably 130 to 250 ° C. If the melting point of the resin is less than 70 ° C, it has no heat resistance and peels off at a high temperature, and if it is higher than 250 ° C, the adhesive strength decreases at a low temperature and may peel off at a low temperature.

(A component of a resin having an acid value of 1 to 200 mgKOH / g that is soluble in xylene at 25 ° C)
The resin having an acid value of 1 to 200 mgKOH / g contains a component soluble in xylene at 25 ° C., but the content thereof is preferably less than 5% by weight. More preferably, it is less than 2% by weight. A component that contains a component soluble in xylene at 25 ° C but softens at less than 70 ° C even if the melting point of the resin having an acid value of 1 to 200 mgKOH / g is 70 ° C or higher when the content is 5% by weight or more. Since it is contained, the adhesive strength may decrease at high temperatures and peel off. It is preferable that the resin having an acid value of 1 to 200 mgKOH / g does not contain a component soluble in xylene at 25 ° C. However, even if a resin having an acid value of 1 to 200 mgKOH / g contains a component soluble in xylene at 25 ° C, the content is 5 If it is less than% by weight, it is firmly adhered. If it is contained in an amount of 5% by weight or more, the adhesive strength is lowered.

(Other resins)
In the thermoplastic hot melt adhesive of the present invention, other resins can be used in combination with the above resin having an acid value of 1 to 200 mgKOH / g. Thermoplastic hot melt adhesives are obtained by themselves or by mixing thermoplastic polymers, tackifiers, waxes and the like. Thermoplastic polymers include ABS, polyamide, polyester, polyurethane, acrylic, polycarbonate, polystyrene, polyethylene, polypropylene, poly-1-butene, polyisobutylene, polymethylpentene, propylene-ethylene copolymer, and ethylene-propylene-diene co-weight. Combined, ethylene / butene-1 copolymers, polyolefins such as ethylene / octene copolymers, cyclic polyolefins such as cyclopentadiene with ethylene and / or propylene copolymers, ethylene / vinyl acetate copolymers (EVA), Polycone introduced with polar groups such as ethylene / ethyl acrylate copolymer (EEA), isobutylene / maleic anhydride copolymer, maleic anhydride-modified polypropylene, maleic acid-modified polypropylene, acrylic acid-modified polypropylene, styrene-based elastomer, etc. Can be mentioned. The tackifier is not particularly limited, but is a petroleum resin such as a phenol resin, a modified phenol resin, a terpene phenol resin, a xylene phenol resin, a cyclopentadiene-phenol resin, a xylene resin, an aliphatic type, an alicyclic group type, or an aromatic type. , Hydrogenated aliphatic, alicyclic, aromatic petroleum resins, phenol-modified petroleum resins, rosin ester resins, hydrogenated rosin ester resins, low molecular weight polystyrene resins, terpene resins, hydrogen Examples thereof include a tackifier resin such as added terpene resin. Waxes include carnauba wax, canderia wax, montan wax, paraffin wax, microwax, fisher tropus wax, polyethylene wax, polypropylene wax, oxides of these waxes, ethylene-acrylic acid copolymer, and ethylene-methacrylic acid. Examples include polymers.

(Additive)
As the thermoplastic hot melt adhesive of the present invention, various additives can be used as needed. For example, antiblocking agents, inorganic fillers, antioxidants, fillers, flame retardants, plasticizers, antistatic agents, light stabilizers, UV absorbers and heavy metal deactivating agents.

Examples of the inorganic filler include particles such as metals, metal oxides and metal hydroxides, and fibrous materials. Specifically, glass fiber, carbon fiber, calcium silicate, calcium titanate, aluminum borate fiber, flake-like glass, talc, kaolin, mica, hydrotalcite, calcium carbonate, zinc carbonate, zinc oxide, monohydrogen phosphate. Calcium, Wallastnite, Silica, Zeolite, Alumina, Boehmite, Aluminum Hydroxide, Titanium Oxide, Silicon Oxide, Magnesium Oxide, Calcium Silica, Alumina Sodium Silate, Magnesium Silica, Carbon Nanochieve, Graphite, Copper, Silver, Aluminum, Nickel , Iron, calcium fluoride, mica, montmorillonite, apatite and the like.
Antioxidants include high molecular weight hindered polyhydric phenol, triazine derivative, high molecular weight hindered phenol, dialkyl phenol sulfide, 2,2-methylene-bis- (4-methyl-6-3-butylphenol), 4 , 4-Methyl-bis- (2,6-di-third-butylphenol), 2,6-di-third-butylphenol-p-cresol, 2,5-di-3-butylhydroquinone, 2,2 , 4-trimethyl-1,2-dihydroquinone, 2,2,4-trimethyl-1,2-dihydroquinone, nickel dibutyl dithiocarbamate, 1-oxy-3-methyl-4-isopropylbenzene, 4,4- Examples thereof include butylidenebis- (3-methyl-6-3-butylphenol), 2-mercaptobenzoimidazole and the like.

Examples of the filler include wet silica, aluminum hydroxide, aluminum oxide, magnesium oxide, montmorillonite, mica, smectite, organic montmorillonite, organic mica, and organic smectite.

Examples of the flame retardant include a phosphorus-containing compound-based flame retardant, a halogen-containing compound-based flame retardant, a sulfonic acid metal salt-based flame retardant, and a silicon-containing compound-based flame retardant.
Examples of the plasticizer include phthalate ester plasticizer, polyester plasticizer, aliphatic dibasic acid ester plasticizer, aliphatic monobasic acid ester plasticizer, phosphoric acid ester plasticizer, and citric acid ester plasticizer. , Epoxy-based plasticizers, trimellitic acid ester-based plasticizers, tetrahydrophthalate ester-based plasticizers, glycol-based plasticizers, bisphenol A alkylene oxide derivatives and the like.
The antistatic agent may be one that is widely used as an antistatic agent for plastics, and specifically, a nonionic surfactant (for example, a fatty acid ester of a polyhydric alcohol, an ethylene oxide adduct of an alkylamine, and an alkyl). Aminium ethylene oxide adduct fatty acid esters, etc.), anionic surfactants (eg, alkylbenzene sulfonates, higher alcohol sulfates, etc.), cationic surfactants (eg, aliphatic amine salts, quaternary ammonium salts). Etc.), amphoteric surfactants (eg, imidazoline type, betaine type, etc.).

Examples of the light stabilizer include hindered amine compounds and benzoate compounds.
Examples of the ultraviolet absorber include a benzophenone-based ultraviolet absorber, a triazine-based ultraviolet absorber, and a benzotriazole-based ultraviolet absorber.
Examples of the heavy metal inactivating agent include salicylic acid derivatives, hydrazide derivatives, oxalic acid amide derivatives and the like.

The above additives can be used alone or in admixture of two or more at any ratio as required.

[Electromagnetic induction heating]
In the electromagnetic induction heating of the present invention, an alternating current is generated by passing a high-frequency alternating current through the coil of the electromagnetic induction heating device, and an eddy current is generated inside the conductive material in the magnetic field to generate this eddy current. This is a heating method in which a conductive material is heated by the eddy current heat based on the eddy current. The higher the frequency of the alternating current flowing through the coil, the faster the change in the magnetic field, the larger the eddy current based on it, and the shorter the heating time. The coil is, for example, a solenoid type coil, and does not necessarily have to be cylindrical, and may be provided with a magnetic material such as an iron core or ferrite inside.
As a heating method, the coil may be heated by applying an electric current above or below the metal layer or the adherend layer to be heated, or a separator may be inserted in the coil and the electric current may be applied to the coil to heat the coil. ..

[Manufacturing method of separator]
In the method for producing a separator of the present invention, a thermoplastic hot melt adhesive is attached to an adherend layer 15 and sandwiched between metal layers 13. For example, the adherend layer 15 and the metal layer 13 may be sandwiched or bonded by applying a dispenser or using a thermoplastic hot melt adhesive as a film in advance. Next, the metal layer 13 and the adherend layer 15 are laminated to the extent that they can be heated by the electromagnetic induction heating device, and a current is passed through the coil of the electromagnetic induction heating device within 5 seconds, and the metal layer 13 and / or the coated layer 13 and / or the coated layer 13 and / or the coated layer 15 are laminated. The layer 15 is heated to melt the thermoplastic hot melt adhesive. Even if the current of the electromagnetic induction heating device is cut off and the heating is completed, the metal layer 13 and the adherend layer 15 are waited until they cool down, and then the thermoplastic hot melt adhesive is cooled and then bonded.

Hereinafter, the present invention will be described based on examples, but the present invention is not limited thereto.

<Synthesis example of resin A having an acid value of 1 to 200 mgKOH / g>
20 parts of maleic anhydride and 375 parts of xylene are charged in 100 parts of polypropylene having a weight average molecular weight (hereinafter abbreviated as Mw) of 10,000 in a 3-port flask equipped with a nitrogen inlet, a thermometer, and a stirrer, and under nitrogen reflux. After raising the temperature to 130 ° C., 0.1 part of benzoyl peroxide is dissolved in 40 parts of xylene and added dropwise for 90 minutes. After dropping, the mixture is reacted at 130 ° C. for 4 hours and then cooled to room temperature for 60 minutes. The obtained suspension was filtered, xylene was removed, and then washing with methyl ethyl ketone was repeated 2-3 times, and washing was performed until maleic anhydride and maleic anhydride alone reaction product were hardly observed in the methyl ethyl ketone by liquid chromatography. continue. The obtained powder of maleic anhydride-modified propylene resin was air-dried to obtain it.
<Example of synthesis of resin B to G having an acid value of 1 to 200 mgKOH>
Using polypropylene having Mw of 7,000, 20,000, 50,000, 100,000, 200,000 and 300,000, respectively, with <Synthesis example of resin A having an acid value of 1 to 200 mgKOH / g>. In the same manner, the maleic anhydride-modified propylene resin (resins B to G) having Mw of the raw material polypropylene of 7,000, 20,000, 50,000, 100,000, 200,000 and 300,000 is prepared. Yeah.

<Resin H with an acid value of 1 to 200 mgKOH>
Primacol 5980I manufactured by Dow Chemical Co., Ltd., which is an ethylene-acrylic acid copolymer, was used.
<Resin I with an acid value of 1 to 200 mgKOH>
As a hydrogenated product of a copolymer of an acid-modified styrene-based aromatic hydrocarbon and a conjugated diene block, Tough Tech M1953 (styrene content 40% by weight, acid value 10 mgKOH / g) manufactured by Asahi Kasei Co., Ltd. was used.
<Resin J with an acid value of 1 to 200 mgKOH>
The copolymer of acid-modified styrene-based aromatic hydrocarbon and conjugated diene block is Kraton FG1901X manufactured by Kraton Polymer Co., Ltd. (styrene content 28% by weight, maleic anhydride added 2.0% by weight, acid value 22 mgKOH / g) was used.
<Resin K>
Novatec LD LC600A manufactured by Japan Polyethylene Corporation, which is polypropylene, was used. Acid value: less than 1 mgKOH / g.
<Resin L>
VS-1047 manufactured by Seiko PMC Corporation, which is a styrene-acrylic acid resin, was used. Acid value: 240 mgKOH / g.

<Manufacturing method of thermoplastic hot melt adhesive resin (1), (2), (4) to (7)>
The thermoplastic resin of the present invention was produced by mixing the above resin with a resin having an acid value of less than 1 and / or 200 mg or more and polypropylene A (FL02A manufactured by Japan Polypropylene Corporation) and blending them with an extruder.
<Thermoplastic hot melt adhesive (3), (8)-(10)>
As the thermoplastic hot melt adhesives (3) and (8) to (10), the resins B, H, I and J were used as they were.

<Measuring method of components soluble in xylene at 25 ° C>
The component soluble in xylene at 25 ° C. in the resin having an acid value of 1 to 200 mgKOH / g was calculated by the following method. The resin pellets were melted by heating at 130 ° C. for 3 hours using about 50 times by weight of xylene, and then allowed to cool overnight at 25 ° C. to precipitate crystallized products. The crystallization was filtered, the filtrate was collected, and concentrated to dryness. Further, it was dried under reduced pressure overnight at 80 ° C. to remove the residual solvent, and a component soluble in xylene at 25 ° C. was obtained. From the weight of the resin pellet and the component soluble in xylene at 25 ° C., the weight% of the component soluble in xylene at 25 ° C. was calculated.
The resins H, I, and J could not be measured because they could be made of toluene.

<Film formation method>
Using an extruded laminator, the thermoplastic hot-melt adhesive shown in Tables 2-1 and 2-2 was laminated on a release-treated PET film (thickness: 25 μm) with different film thicknesses, and wound at the winding section. A thermoplastic adhesive layer was prepared.
The processing conditions are shown below.
Extruded laminator: 400M / M test made by Musashinokikai Resin temperature directly under the EXT laminator die: 140-240 ° C (adjusted appropriately by resin MFR etc.)
Processing speed: 30 m / min T die width: 400 mm
Cooling roll surface temperature: 20 ° C

<Manufacturing method of adhesive structure>
In order to evaluate the performance of the separator manufacturing method of the present invention, an adhesive structure was prepared by the following manufacturing method and evaluated. The composition and evaluation results of the thermoplastic hot melt adhesive used are shown in Tables 1-1 and 1-2 and Tables 2-1 and 2-2.

An electromagnetic induction heating device in which a metal layer (100 μm aluminum plate), a thermoplastic hot melt adhesive layer (thickness: 20 to 500 μm), and an adherend layer (100 μm aluminum plate) are laminated, and an input voltage: 100 V and a power consumption: 550 W. The thermoplastic hot-melt adhesive is softened by heating for 1 to 5 seconds, and when the heating is completed, the thermoplastic hot-melt adhesive is pressure-bonded by an electromagnetic induction heating device to cool and solidify the thermoplastic hot-melt adhesive, and an adhesive structure is obtained. Be done.

<Adhesive strength>
The T peel strength of the bonded structure was measured using a tensile tester. The measurement conditions are as follows.
・ Sample width: 10 mm
-Measurement temperature: 23 ° C, 80 ° C
・ Tensile speed: 10 mm / min
The evaluation results were 0 for 80N / 10mm or more and x for less than 80N / 10mm.

<Adhesive strength after warm water>
After immersing the adhesive structure in warm water at 80 ° C. for 96 hours, the T peel strength of the adhesive structure was measured using a tensile tester. The measurement conditions are as follows.
・ Sample width: 10 mm
・ Measurement temperature: 23 ° C
・ Tensile speed: 10 mm / min
The evaluation results were 100 N / 10 mm or more: ⊚, 80 N / 10 mm or more: 〇, 20 N / 10 mm or less: Δ, 20 N / 10 mm or less: ×. 〇 and ◎ were accepted.

(Comparative Examples 1 and 2)
The results of evaluation are shown in Comparative Example 1 using a polypropylene resin having an acid value of 1 mgKOH / g and Comparative Example 2 using a styrene-acrylic acid resin having an acid value of 240 mgKOH / g. The adhesive strength was low in all the comparative examples.

(Comparative Example 3)
In Comparative Example 3, an adhesive resin (1) was used, and a sample was prepared by heat sealing (250 ° C.) and evaluated. The adhesive strength was low.

By using the method for producing a separator of the present invention, a separator having adhesive strength (normal temperature and 80 ° C.) and adhesive strength after warm water and a fuel cell using the same can be obtained by adhering in a short time.

1 fuel cell, 11 separator, 12 thermoplastic hot melt adhesive layer,
13 metal layer, 14 coolant flow path, 15 adherend layer, 17,19 gas flow path,
18 power generator, 41 anode layer, 42 cathode layer, 31, 32 gas diffusion layer,
71 Electrolyte membrane

Claims (8)

A method for manufacturing a separator for a fuel cell, which comprises a step of adhering a laminate formed by laminating a metal layer and a thermoplastic hot melt adhesive layer in this order and an adherend layer, wherein the step is electromagnetic induction heating. A method for producing a separator for a fuel cell, which comprises a step of heating a metal layer with a fuel, and the thermoplastic hot melt adhesive contains a resin having an acid value of 1 to 200 mgKOH / g. The method for producing a separator for a fuel cell according to claim 1, wherein the resin contains a copolymer of ethylene and (meth) acrylic acid and / or a polyolefin. The method for producing a fuel cell separator according to claim 1 or 2, wherein the resin contains a copolymer of an acid-modified styrene-based aromatic hydrocarbon and a conjugated diene block, or a hydrogenated product thereof. .. The method for manufacturing a separator for a fuel cell according to any one of claims 1 to 3, wherein the melting point of the resin is 70 to 250 ° C. The fuel cell separator according to any one of claims 1 to 4, wherein the thermoplastic hot melt adhesive contains a component soluble in xylene at 25 ° C., but the content thereof is less than 5% by weight. Manufacturing method. The method for manufacturing a fuel cell separator according to any one of claims 1 to 5, wherein the adherend layer is a metal layer. The method for manufacturing a separator for a fuel cell according to any one of claims 1 to 6, wherein the time required for the step of heating the metal layer by electromagnetic induction heating is within 5 seconds. A method for manufacturing a fuel cell, which comprises the method for manufacturing a separator for a fuel cell according to any one of claims 1 to 7.

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