Adhesive sealing film for fuel cell

Abstract

Provided is an adhesive sealing film for a fuel cell, which uses a resin composition capable of suppressing a decrease in tensile fracture stress. An adhesive sealing film (10) for a fuel cell has a base material layer (11) made of a resin as a forming material, and adhesive layers (13) laminated on both surfaces of the base material layer (11) with intermediate layers (12) interposed therebetween. The base material layer (11) is formed from a resin composition containing a polyester resin other than a liquid crystal polymer, a low-melting-point liquid crystal polymer having a crystal melting temperature of 250 DEG C or less, and an acid-modified polyethylene resin, the intermediate layer (12) is formed from an acid-modified polyethylene resin or an imine-modified polyolefin resin, and the adhesive layer (13) is formed from an acid-modified polypropylene resin.

Description

Technical Field

[0001] The invention relates to an adhesive sealing film for a fuel cell. Background Art

[0002] Among polyester resins, liquid crystal polymers have good hydrolysis resistance, but liquid crystal polymers with a crystal melting temperature of 280°C or higher are difficult to be mixed with other resins to form polymer alloys. Therefore, resin compositions obtained by polymer alloying low-melting-point liquid crystal polymers with a crystal melting temperature of 250°C or lower with other resins are commercially available (for example, see Patent Documents 1 and 2).

[0003] In addition, Patent Document 3 discloses a hot-melt adhesive resin laminate.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-214677

[0005] Patent Document 2: Japanese Patent Application Publication No. 2022-83103

[0006] Patent Document 3: Japanese Patent Application Publication No. 2019-137853 Summary of the invention

[0007] A resin composition in which a low melting point liquid crystal polymer having a crystal melting temperature of 250° C. or less is finely dispersed has a problem that the tensile breaking stress of the resin composition decreases due to the low hydrolysis resistance of the liquid crystal polymer, and when stored or used under humid conditions.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an adhesive sealing film for a fuel cell using a resin composition capable of suppressing a decrease in tensile breaking stress.

[0009] The first scheme is: an adhesive sealing film for a fuel cell, comprising a base layer formed of a resin as a forming material and an adhesive layer laminated on both sides of the base layer via an intermediate layer, the base layer being formed of a resin composition containing a polyester resin other than a liquid crystal polymer, a low-melting point liquid crystal polymer having a crystal melting temperature of less than 250°C, and an acid-modified polyethylene resin, the intermediate layer being formed of an acid-modified polyethylene resin or an imine-modified polyolefin resin, and the adhesive layer being formed of an acid-modified polypropylene resin.

[0010] A second embodiment is the adhesive sealing film for a fuel cell according to the first embodiment, wherein the base material layer contains an acid-modified polyolefin compound as a compatible material.

[0011] A third aspect is the adhesive sealing film for a fuel cell according to the first aspect or the second aspect, wherein the intermediate layer contains an acid-modified polyolefin compound as a compatible material.

[0012] The fourth scheme is: an adhesive sealing film for a fuel cell according to any one of the first to third schemes, wherein in the substrate layer, taking the entire resin composition as 100 parts by weight, the polyester resin other than the liquid crystal polymer is 40 parts by weight to 60 parts by weight, the low-melting point liquid crystal polymer is 20 parts by weight to 40 parts by weight, and the acid-modified polyethylene resin is 5 parts by weight to 30 parts by weight.

[0013] According to the present invention, there can be provided an adhesive sealing film for a fuel cell using a resin composition capable of suppressing a decrease in tensile breaking stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a cross-sectional view illustrating an adhesive sealing film for a fuel cell according to an embodiment.

[0015] (Explanation of Reference Numerals)

[0016] 10 ... an adhesive sealing film for a fuel cell, 11 ... a base material layer, 12 ... an intermediate layer, 13 ... an adhesive layer. DETAILED DESCRIPTION

[0017] Hereinafter, the present invention will be described based on preferred embodiments.

[0018] The fuel cell adhesive sealing film 10 of the embodiment includes a base layer 11 formed of a resin and an adhesive layer 13 laminated on both sides of the base layer 11 via an intermediate layer 12. The layer structure of the fuel cell adhesive sealing film 10 is composed of five layers: adhesive layer 13 / intermediate layer 12 / base layer 11 / intermediate layer 12 / adhesive layer 13.

[0019] The base material layer 11 is formed of a resin composition containing a polyester resin other than a liquid crystal polymer, a low melting point liquid crystal polymer having a crystal melting temperature of 250° C. or less, and an acid-modified polyethylene resin.

[0020] The base material layer 11 contains a polyester resin other than a liquid crystal polymer. These polyester resins are non-liquid crystal polyester resins, and may be, for example, linear polyester resins obtained by polycondensation of a dicarboxylic acid component and a diol component.

[0021] Examples of the dicarboxylic acid component of the polyester resin include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene-1,4-dicarboxylic acid, and naphthalene-2,6-dicarboxylic acid; and aliphatic dicarboxylic acids such as adipic acid and sebacic acid.

[0022] Examples of the diol component of the polyester resin include linear diols such as ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, and 1,6-hexamethylene glycol; branched diols such as neopentyl glycol and 2,2-dialkyl-1,3-propylene glycol; cyclic diols such as cyclopentane dimethanol and cyclohexanedimethanol, etc. Examples of the alkyl group of the side chain branching from the main chain of the branched diol include methyl, ethyl, propyl, and butyl.

[0023] Specific examples of the polyester resin include, but are not particularly limited to, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, and modified polyesters obtained by modifying a portion of the dicarboxylic acid components and / or diol components in these polyesters with other dicarboxylic acid components and / or diol components.

[0024] The base material layer 11 contains a low melting point liquid crystal polymer having a crystal melting temperature of 250° C. or less. The liquid crystal polymer is a thermoplastic resin that exhibits liquid crystallinity when melted, and is preferably a liquid crystal polymer formed of a polyester resin. The polyester resin other than the liquid crystal polymer may be a thermoplastic resin that does not exhibit liquid crystallinity when melted.

[0025] The low melting point liquid crystal polymer may be composed of only one type of low melting point liquid crystal polymer or may be a mixture of a plurality of types of low melting point liquid crystal polymers.

[0026] The low melting point liquid crystal polymer may be a liquid crystal polyester or a liquid crystal polyester amide which is called a thermotropic liquid crystal polymer and forms an anisotropic melting layer, and preferably a liquid crystal polyester.

[0027] The crystal melting temperature of the low melting point liquid crystal polymer is the temperature of the crystal melting peak measured using a differential scanning calorimeter. Regarding the measurement method using a differential scanning calorimeter, after observing the endothermic peak temperature (Tm1) when measured at a temperature increase of 20°C / minute from room temperature, it is kept at a temperature 20°C to 50°C higher than Tm1 for 10 minutes, then, after cooling the sample to room temperature at a temperature decrease of 20°C / minute, the endothermic peak is observed when measured again at a temperature increase of 20°C / minute, and the temperature showing the top of the peak is taken as the crystal melting temperature of the liquid crystal polymer. The crystal melting temperature of the low melting point liquid crystal polymer is below 250°C, preferably 160°C to 240°C, more preferably 170°C to 230°C, and particularly preferably 200°C to 230°C.

[0028] As repeating units constituting the low melting point liquid crystal polymer, for example, aromatic hydroxycarboxylic acid units (-O-Ar-CO-), aromatic dicarboxylic acid units (-CO-Ar-CO-), aromatic diol units (-O-Ar-O-), aromatic aminocarboxylic acid units (-NH-Ar-CO-), aromatic hydroxylamine units (-O-Ar-NH-), aromatic diamine units (-NH-Ar-NH-), aliphatic diol units (-O-Ra-O-) and aliphatic dicarboxylic acid units (-O-Ra-O-). Wherein, -Ar- represents an aromatic group, and -Ra- represents an aliphatic group. The -CO- groups contained in these units are not limited to being derived from carboxylic acid (-CO-OH), but may also be derived from acylates (-CO-O-COR), ester derivatives (-CO-OR), acyl halides (-CO-X), etc. In addition, the -O- groups and the -NH- groups are not limited to being derived from hydroxyl (-OH) and amino (-NH-) groups, respectively. 2 ), or may be derived from acylate (-O-COR and -NH-COR), etc. wherein R represents an organic group such as an alkyl group or an aryl group, and X represents a halogen atom.

[0029] As long as the polyester is established as a low melting point liquid crystal polymer, the repeating units constituting these liquid crystal polymers may be only one kind or a combination of two or more kinds, but it is desirable to include at least one hydroxycarboxylic acid unit. As the low melting point liquid crystal polymer, it is preferred that each repeating unit includes a fully aromatic low melting point liquid crystal polymer with an aromatic group.

[0030] Specific examples of the aromatic hydroxycarboxylic acid unit include units derived from 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy-2-naphthoic acid, 7-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4'-hydroxyphenyl-4-benzoic acid, 3'-hydroxyphenyl-4-benzoic acid, 4'-hydroxyphenyl-3-benzoic acid, and alkyl, alkoxy or halogen-substituted products thereof. Among them, from the viewpoint of heat resistance and mechanical strength of the obtained liquid crystal polymer, and easy adjustment of the melting point, preferably, units derived from one or more selected from 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid.

[0031] Specific examples of the aromatic dicarboxylic acid unit include units derived from terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 4,4'-dicarboxybiphenyl, 3,4'-dicarboxybiphenyl and 4,4"-dicarboxyterphenyl, and alkyl, alkoxy or halogen-substituted products thereof. Among them, from the viewpoint of effectively improving the heat resistance of the obtained liquid crystal polymer, preferably, the unit is derived from one or more selected from terephthalic acid, isophthalic acid and 2,6-naphthalene dicarboxylic acid, and more preferably, the terephthalic acid unit or the 2,6-naphthalene dicarboxylic acid unit.

[0032] Specific examples of the aromatic diol unit include hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 2,2'-dihydroxybinaphthyl, and units derived from alkyl, alkoxy or halogen-substituted products thereof. Among them, from the viewpoint of excellent reactivity during polymerization, preferably, units derived from one or more selected from hydroquinone, resorcinol, 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene, more preferably, units derived from one or more selected from hydroquinone, 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene.

[0033] Specific examples of the aliphatic diol unit include units derived from ethylene glycol, 1,4-butanediol, and 1,6-hexanediol. In addition, during the production, a polymer containing an aliphatic diol such as polyethylene terephthalate and polybutylene terephthalate can be reacted with the aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, and their acylates, ester derivatives, acyl halides, etc.

[0034] Specific examples of the aliphatic dicarboxylic acid unit include units derived from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, fumaric acid, maleic acid, 1,4-cyclohexanedicarboxylic acid, and hexahydroterephthalic acid. Among them, units derived from oxalic acid, succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and 1,4-cyclohexanedicarboxylic acid are preferred from the viewpoint of achieving excellent reactivity during polymerization.

[0035] The base layer 11 contains an acid-modified polyethylene resin. Examples of polyethylene include low-density polyethylene, high-density polyethylene, and linear low-density polyethylene. The proportion of the acid-modified polyethylene resin in the base layer 11 is, for example, 5% by weight to 30% by weight.

[0036] Examples of methods for producing the acid-modified polyethylene resin include a method of graft-modifying a polyethylene resin that is not acid-modified by melt blending with a monomer containing an acid functional group; and a method of copolymerizing an ethylene monomer with a monomer containing an acid functional group.

[0037] Examples of the monomer containing an acid functional group include monomers containing carboxylic acid groups and monomers containing acid anhydride groups. Examples of the monomer containing a carboxylic acid group include α,β-unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, maleic acid, nadic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, tetrahydrophthalic acid, and endo-bicyclo[2.2.1]-5-heptene-2,3-dicarboxylic acid (nadic acid).

[0038] Examples of the acid anhydride group-containing monomer include unsaturated dicarboxylic acid anhydride monomers such as maleic anhydride, nadic anhydride, itaconic anhydride, citraconic anhydride, and nadic anhydride.

[0039] As the manufacturing method of the resin composition of the substrate layer 11, a method of mixing polyester resin, low melting point liquid crystal polymer, and acid-modified polyethylene resin by melt blending or the like can be cited. It is also possible to first mix two of the three types of polyester resin, low melting point liquid crystal polymer, and acid-modified polyethylene resin and then add the remaining one to mix. As the device for melt blending, there is no particular limitation, and a single screw extruder, a multi-screw extruder, a Banbury mixer, a plastomill, a heated roll kneading machine, etc. can be used. Furthermore, mixing can also be carried out in the following manner: after dry blending polyester resin, low melting point liquid crystal polymer, and acid-modified polyolefin, a film is made using an extruder or the like.

[0040] As a result of mixing the resin composition of the substrate layer 11, a sea-island structure can be formed in which the polyester resin constitutes a sea portion, and the low-melting-point liquid crystal polymer and the acid-modified polyethylene resin respectively constitute island portions. Since the acid-modified polyethylene resin is well dispersed in the polyester resin and the low-melting-point liquid crystal polymer, the hydrolysis of the ester bonds and the like contained in the polyester resin and the low-melting-point liquid crystal polymer can be suppressed even in a high-temperature and high-humidity environment such as during thermoforming. Furthermore, the decrease in the tensile breaking stress of the resin composition can be suppressed.

[0041] Preferably, the proportion of the polyester resin other than the liquid crystal polymer is 40 to 60 parts by weight, the low melting point liquid crystal polymer is 20 to 40 parts by weight, and the acid-modified polyethylene resin is 5 to 30 parts by weight, based on 100 parts by weight of the total resin composition of the substrate layer 11. It is preferred that the proportion of the polyester resin other than the liquid crystal polymer is greater than that of the low melting point liquid crystal polymer, and it is preferred that the proportion of the low melting point liquid crystal polymer is greater than that of the acid-modified polyethylene resin.

[0042] The resin composition of the substrate layer 11 may contain any component. Examples of the arbitrary resin component include polyolefin resins, olefin elastomers, styrene elastomers, etc. Additives are not particularly limited, and examples thereof include fillers, colorants, antioxidants, defoamers, leveling agents, light absorbers, etc.

[0043] The resin composition of the substrate layer 11 may contain an acid-modified polyolefin compound as a compatible material. Examples of the acid-modified polyolefin compound include acid-modified polyolefins having a molecular weight selected from the range of 9,000 to 160,000. Examples of the acid-modified polyethylene resin of the substrate layer 11 include acid-modified polyethylene having a molecular weight of 200,000 or more. The proportion of the compatible material in the substrate layer 11 may be 1% by weight to 3% by weight.

[0044] The resin composition of the substrate layer 11 may be a composition that does not contain a high melting point liquid crystal polymer whose crystal melting temperature exceeds 250° C. Furthermore, the resin composition of the substrate layer 11 may be a composition that does not contain a resin component whose melting temperature (melting point) exceeds 250° C. The thickness of the substrate layer 11 is not particularly limited, and may be 60 μm to 120 μm.

[0045] The intermediate layer 12 is formed of an acid-modified polyethylene resin or an imine-modified polyolefin resin.

[0046] As the acid-modified polyethylene resin of the intermediate layer 12, there can be cited graft polymers obtained by grafting and modifying polyethylene resins that are not acid-modified with monomers containing acid functional groups by melt blending, copolymers obtained by copolymerizing ethylene monomers with monomers containing acid functional groups, etc. As the monomers containing acid functional groups, there can be cited monomers containing carboxylic acid groups, and monomers containing acid anhydride groups. As polyethylene, there can be cited low-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc.

[0047] Examples of the imine-modified polyolefin resin of the intermediate layer 12 include polymer compounds obtained by modifying polyolefin resins such as polyethylene resins and polypropylene with imine compounds.

[0048] The intermediate layer 12 can improve the adhesive force (interlayer peel strength) between the base layer 11 and the adhesive layer 13. The thickness of the intermediate layer 12 is not particularly limited, and can be 1 μm to 20 μm. The acid-modified polyethylene resin contained in the intermediate layer 12 can be of the same grade as the acid-modified polyethylene resin contained in the base layer 11, or can be of a different grade.

[0049] The intermediate layer 12 may contain an acid-modified polyolefin compound as a compatible material. Examples of the acid-modified polyolefin compound include acid-modified polyolefins having a molecular weight selected from the range of 9,000 to 160,000. Examples of the acid-modified polyethylene resin of the intermediate layer 12 include acid-modified polyethylene having a molecular weight of 200,000 or more. The proportion of the compatible material in the intermediate layer 12 may be 1% by weight to 3% by weight.

[0050] The resin composition of the intermediate layer 12 may contain any component. As the arbitrary resin component, polyolefin resin, olefin elastomer, styrene elastomer, etc. can be cited. As additives, there are no particular restrictions, and fillers, colorants, antioxidants, defoamers, leveling agents, light absorbers, etc. can be cited.

[0051] The adhesive layer 13 is formed of an adhesive polypropylene resin such as an acid-modified polypropylene resin. Examples of the acid-modified polypropylene resin include graft polymers obtained by grafting and modifying a non-acid-modified polypropylene resin with a monomer containing an acid functional group by melt blending, copolymers obtained by copolymerizing a propylene monomer with a monomer containing an acid functional group, and the like. Examples of the monomer containing an acid functional group include the monomer containing a carboxylic acid group and the monomer containing an acid anhydride group. Examples of polypropylene include homopolypropylene, block polypropylene, and random polypropylene.

[0052] The adhesive layer 13 can obtain good adhesion to the adherend of the fuel cell adhesive sealing film 10. The thickness of the adhesive layer 13 is not particularly limited, but may be 10 μm to 40 μm.

[0053] The resin composition of the adhesive layer 13 may contain any component. As any resin component, polyolefin resin, olefin elastomer, styrene elastomer, etc. may be cited. As additives, there is no particular limitation, and fillers, colorants, antioxidants, defoamers, leveling agents, light absorbers, etc. may be cited. As antioxidants, phenolic, phosphite, thioether, etc. may be used alone or in combination.

[0054] It is particularly preferred to add an antioxidant to the resin layer serving as the outermost layer.

[0055] The adhesive sealing film 10 for a fuel cell of the embodiment can be used as an adhesive material, a sealing material, etc. in a fuel cell. The adhesive sealing film 10 for a fuel cell of the embodiment can be suitably used as a gasket of a fuel cell, for example.

[0056] As the electrolyte membrane of the fuel cell, a known or commercially available solid polymer electrolyte membrane can be used. For example, a hydrogen ion conductive polymer electrolyte, a perfluorosulfonic acid-based fluorine ion exchange resin, an anion conductive solid polymer electrolyte membrane, etc. can be listed. A catalyst layer of platinum, a platinum alloy, a platinum compound, etc., which is a cathode catalyst or an anode catalyst, can be stacked on the surface of the electrolyte membrane. In a single cell (cell) of a fuel cell, a gasket is arranged on both sides of a membrane electrode complex including an electrolyte membrane and a catalyst layer, separated by an auxiliary gasket. The auxiliary gasket and the gasket are formed in a ring or frame shape in a manner surrounding the periphery of the membrane electrode complex.

[0057] Example

[0058] Hereinafter, the present invention will be specifically described based on examples.

[0059] <Base material layer>

[0060] A polymer alloy of a polyester resin and a low-melting-point liquid crystal polymer was melt-blended with an acid-modified polyethylene resin, and the resulting resin composition was formed into a film having a thickness of 90 μm to obtain a base material layer.

[0061] As the polyester resin and the low melting point liquid crystal polymer, a polymer alloy (trade name: TECROS (registered trademark) T-440HS, manufactured by Ueno Pharmaceutical Co., Ltd., "PET / LCP" in the table) obtained by mixing polyethylene terephthalate (PET) and liquid crystal polymer (LCP) in a weight ratio of 60:40 was used. The liquid crystal polymer contained in the polymer alloy is a low melting point liquid crystal polymer having a crystal melting temperature of 220°C.

[0062] As the acid-modified polyethylene resin, a commercially available acid-modified polyethylene (trade name: ADMER (registered trademark) SF728, manufactured by Mitsui Chemicals, Inc., "APE" in the table) was used. In No. 1, only PET / LCP (without APE) was used, in No. 2, the weight ratio of PET / LCP to APE was set to 90:10, and in No. 3, the weight ratio of PET / LCP to APE was set to 80:20.

[0063] Regarding the measurement of tensile stress at break, the film of the obtained substrate layer was punched into a dumbbell shape of No. 5 and the obtained sample was measured under the conditions of chuck distance: 80 mm, mark distance: 45 mm, and stretching speed: 300 mm / min. After preparing each sample so that the stretching direction is the MD direction (flow direction) or the TD direction (width direction), the tensile stress at break was calculated from the cross-sectional area (width 6 mm, thickness 0.09 mm) at the narrow width portion of the sample.

[0064] The pressure cooker test (PCT) was carried out under the conditions of 110°C, 85% RH, and 96h. The tensile stress at break was measured before and after PCT for the same sample, and the maintenance rate before and after PCT was calculated. The maintenance rate was obtained by (tensile stress at break after PCT) / (tensile stress at break before PCT)×100(%). The results of the tensile stress at break are shown in Table 1.

[0065]

Table 1

[0066]

[0067] As shown in Table 1, it was confirmed that the addition of an acid-modified polyethylene resin could suppress a decrease in tensile breaking stress after PCT.

[0068] <Adhesive sealing film for fuel cells>

[0069] An adhesive sealing film for a fuel cell consisting of five layers: adhesive layer / intermediate layer / base material layer / intermediate layer / adhesive layer was prepared. The thickness of the intermediate layer was 5 μm, and the thickness of the adhesive layer was 25 μm.

[0070] As the intermediate layers of No. 1 to 3, APE of the same grade as the acid-modified polyethylene resin used for the substrate layer was used. In the intermediate layers of No. 4 to 6, APE and a compatible material were mixed at a weight ratio of 98:2. The compatible materials used were C1 (trade name: Youmex (registered trademark) 1001, manufactured by Sanyo Chemical Industries, Ltd., acid-modified polypropylene resin) in No. 4, C2 (trade name: Rikeaid (registered trademark) MG-670P, manufactured by Riken Vitamin Co., Ltd., acid-modified polypropylene resin) in No. 5, and C3 (trade name: Rikeaid (registered trademark) KG-005P, manufactured by Riken Vitamin Co., Ltd., silica-based polypropylene resin) in No. 6.

[0071] As the adhesive layer, a resin composition was used in which two acid-modified polypropylene resins (trade name: ADMER (registered trademark) QE060, manufactured by Mitsui Chemicals, Inc., "APP1" in the table; and trade name: ADMER (registered trademark) QF575, manufactured by Mitsui Chemicals, Inc., "APP2" in the table) and an antioxidant (a mixture of phenolic, phosphite and thioether resins) were mixed in a weight ratio of 55:40:5, and 3500 ppm of the resin composition was added relative to the resin component of the adhesive layer.

[0072] The interlayer peel strength of the adhesive sealing film for fuel cells was measured as an average of N=3 (average of values ​​measured three times).

[0073]

Table 2

[0074]

[0075] As shown in Table 2, when no compatible material is used, the interlayer peeling strength of sample No. 2 is the highest. When a compatible material is used, the interlayer peeling strength is further improved.

Claims

1. An adhesive sealing film for a fuel cell, comprising a base layer formed of a resin and adhesive layers laminated on both sides of the base layer via an intermediate layer, wherein: The substrate layer is formed of a resin composition containing a polyester resin other than a liquid crystal polymer, a low melting point liquid crystal polymer having a crystal melting temperature of 250° C. or less, and an acid-modified polyethylene resin. The intermediate layer is formed of an acid-modified polyethylene resin or an imine-modified polyolefin resin. The adhesive layer is formed of an acid-modified polypropylene resin.

2. The adhesive sealing film for a fuel cell according to claim 1, wherein: The base material layer contains an acid-modified polyolefin compound as a compatible material.

3. The adhesive sealing film for a fuel cell according to claim 1, wherein: The intermediate layer contains an acid-modified polyolefin compound as a compatible material.

4. The adhesive sealing film for a fuel cell according to claim 1, wherein: In the substrate layer, taking the entire resin composition as 100 parts by weight, the proportions are 40 to 60 parts by weight of the polyester resin other than the liquid crystal polymer, 20 to 40 parts by weight of the low-melting point liquid crystal polymer, and 5 to 30 parts by weight of the acid-modified polyethylene resin.

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