Classifications

• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• This disclosure relates to a gasket member for a fuel cell.
• hot melt adhesive compositions have come to be used as adhesive films or sheets (hereinafter collectively referred to as "adhesive members") in chemical batteries such as lithium ion batteries and fuel cells that are incorporated into notebook computers, smartphones, tablets, automobiles, etc., as well as physical batteries such as solar cells and capacitors. It is known that relatively good adhesive strength can be obtained by using hot melt adhesive compositions whose main component is an acid-modified olefin thermoplastic resin (hereinafter also referred to as “acid-modified polyolefin”) to bond metal substrates such as iron, aluminum, titanium, and other metals, as well as alloys thereof, which are used as the substrates for the components of these batteries.
• acid-modified polyolefin an acid-modified olefin thermoplastic resin
• fuel cells operate in a humid atmosphere to improve the proton conductivity of the electrolyte membrane, and because water is generated during the power generation reaction, the components that make up the fuel cell must have high hydrolysis resistance.
• output density can be improved by increasing the operating temperature of the fuel cell, there is a demand for use in high-temperature environments (e.g., 100°C or higher) from the perspective of miniaturizing the fuel cell.
• Patent Document 1 describes a gasket member for a polymer electrolyte fuel cell that is composed of a laminate including at least a base layer and adhesive layers arranged on both sides of the base layer, and the laminate has a breaking elongation retention rate of 60% or more after being left in water at 120°C for 300 hours.
• Patent Document 2 describes a gasket member for a polymer electrolyte fuel cell that is composed of a laminate including at least a base layer and adhesive layers arranged on both sides of the base layer, and the base layer contains polyphenylsulfone.
• the problem that one embodiment of the present disclosure aims to solve is to provide a gasket member for a fuel cell that has excellent adhesive durability in an environment where high temperatures and moisture are present.
• a gasket member for a fuel cell comprising a base material layer and adhesive layers disposed on both sides of the base material layer, the base material layer containing polyimide, having a breaking stress of 50 N/ mm2 or more and a breaking elongation of 50% or more.
• a gasket member for a fuel cell that has excellent adhesion durability even in high temperature and moisture-containing environments.
• the gasket member for a fuel cell according to the present disclosure is described in detail below. The description below may be based on a representative embodiment of the gasket member for a fuel cell according to the present disclosure, but the gasket member for a fuel cell according to the present disclosure is not limited to such an embodiment, and can be modified as appropriate within the scope of the purpose of the present disclosure.
• a numerical range expressed using “to” means a range that includes the numerical values before and after “to” as the lower and upper limits.
• “high temperature” means 100° C. or higher.
• an "environment in which moisture is present” is, for example, an environment in which an object is held in water.
• the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range.
• the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.
• the molecular weight of a compound having a molecular weight distribution is the weight average molecular weight (Mw).
• Mw weight average molecular weight
• the gasket member for a fuel cell according to the present disclosure (hereinafter also referred to simply as the "gasket member”) comprises a base material layer and adhesive layers disposed on both sides of the base material layer, the base material layer containing polyimide, and having a breaking stress of 50 N/mm2 or more and a breaking elongation of 50% or more.
• the substrate layer is the middle layer, and the adhesive layer is the surface layer.
• a primer layer may be further disposed between the substrate layer and the adhesive layer.
• the primer layer is a layer that contributes to improving the adhesive strength between the substrate layer and the adhesive layer.
• the surface layer is a layer disposed on the upper and lower surfaces
• the intermediate layer is a layer other than the surface layer
• Typical layer configurations of gasket components include a three-layer structure of adhesive layer/substrate layer/adhesive layer, and a five-layer structure of adhesive layer/primer layer/substrate layer/primer layer/adhesive layer.
• the gasket member according to the present disclosure is configured to include a base material layer and adhesive layers disposed on both sides of the base material layer, and is presumed to have improved hydrolysis resistance and excellent adhesion durability even in a high temperature and moisture-containing environment because the base material layer contains polyimide and has a breaking stress of 50 N/ mm2 or more and a breaking elongation of 50% or more.
• Patent Documents 1 and 2 do not mention that the base material layer contains polyimide.
• adhesive durability is evaluated by preparing a test piece from a bonded assembly obtained by adhering the adhesive layer of a gasket member to an adherend (specifically, a SUS304 plate with a thickness of 0.1 mm), and then holding the test piece in water at 120°C for 500 hours, after which the test piece is evaluated based on the peel strength. Details of the evaluation method and conditions for adhesive durability are described in the Examples below.
• the base layer contains polyimide. By containing polyimide, the base layer has excellent heat resistance and hydrolysis resistance. In addition, when a primer layer is disposed, the base layer has excellent adhesion to the primer layer.
• Polyimide is a polymer that contains imide bonds in its molecules.
• the total amount of polyimide in the substrate layer is preferably 60% by mass or more, and more preferably 70% by mass or more. There is no particular upper limit to the total amount of polyimide in the substrate layer, but in one embodiment of the present invention, the total amount of polyimide in the substrate layer is preferably 99.9% by mass or less, more preferably 98% by mass or less, and even more preferably 95% by mass or less.
• the substrate layer may contain a polymer other than polyimide (hereinafter also referred to as "other polymer A”) for the purposes of heat resistance, hydrolysis resistance, ease of formability, etc.
• other polymer A a polymer other than polyimide
• polymer A examples include, for example, phenol resin, urea resin, melamine resin, benzoguanamine resin, alkyd resin, unsaturated polyester resin, vinyl ester resin, diallyl terephthalate resin, silicone resin, urethane resin, furan resin, ketone resin, xylene resin, benzoxazine resin, active ester resin, aniline resin, cyanate ester resin, styrene-maleic anhydride (SMA) resin, polyethylene resin, polypropylene resin, polystyrene resin, rubber-modified polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene terephthalate resin, ethylene vinyl alcohol resin, cellulose acetate resin, ionomer resin, polyacrylonitrile
• Such resins include phthalate resins, polylactic acid resins, polyphenylene ether resins, modified polyphenylene ether resins, polycarbonate resins, polyarylate resins, polyether ether ketone resins, polyketone resins, liquid crystal polyester resins, fluororesins, syndiotactic polystyrene resins, cyclic polyolefin resins, ⁇ -olefin copolymers, propylene-based elastomers, polyisoprene, hydrogenated polyisoprene, polybutadiene, cycloolefin polymers, cycloolefin copolymers, polyamines, polyamides, melamine resins, urea resins, styrene-based thermoplastic resins, hydroxyl-modified polyolefin resins, glycidyl methacrylate-modified polyolefin resins, polyamide-imide resins, polyphenylsulfone
• the content of the other polymer in the base layer may be, for example, 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and particularly preferably 5% by mass or more.
• the content of the other polymer A is within such a range, the improvement effect of the other polymer A in the gasket member is enhanced.
• the content of the other polymer A in the base layer is preferably 50% by mass or less, more preferably 35% by mass or less, and particularly preferably 20% by mass or less.
• the gasket member can further improve its heat resistance, hydrolysis resistance, and ease of moldability.
• the breaking stress of the base layer is preferably 100 N/mm 2 or more, and more preferably 150 N/mm 2 or more.
• the upper limit of the breaking stress is, for example, 500 N/mm 2 .
• the breaking elongation of the base layer is preferably 50% or more, and more preferably 60% or more.
• the upper limit of the breaking elongation is, for example, 200%.
• the base layer preferably has a breaking elongation retention rate of 50% or more, more preferably 60% or more, and even more preferably 70% or more after being kept in water at 120° C. for 3000 hours.
• the breaking elongation retention rate is 50% or more, the adhesion durability is further improved.
• the base layer preferably has a breaking stress retention of 100% or less, more preferably 95% or less, and even more preferably 90% or less, after being kept in water at 120° C. for 3000 hours. When the breaking stress retention is 100% or less, the adhesion durability is further improved.
• the breaking elongation retention rate and the breaking stress retention rate are measured by the following method.
• the base material layer is peeled off from the gasket member.
• the breaking stress (initial breaking stress) and breaking elongation (initial breaking elongation) of the peeled sample are measured.
• the peeled sample is immersed in water at 120°C and held for 3000 hours, after which the breaking stress and breaking elongation are measured.
• the measured values obtained are divided by the initial breaking stress and initial breaking elongation to calculate the breaking stress retention and breaking elongation retention.
• the breaking stress and breaking elongation are measured by punching out a No.
• Breaking stress retention rate (%) (breaking stress after 3000 hours in water at 120°C ⁇ initial breaking stress) x 100
• Breaking elongation retention rate (%) (breaking elongation after being held in water at 120°C for 3000 hours / initial breaking elongation) x 100
• the softening point of the base layer is preferably 175°C or higher, more preferably 180°C or higher, and particularly preferably 185°C or higher. Having a softening point within this range improves the heat resistance of the gasket member.
• the storage modulus of the base layer at 160°C is preferably 500 MPa or more, more preferably 700 MPa or more, and particularly preferably 1000 MPa or more.
• the storage modulus of the base layer at 170°C is preferably 500 MPa or more, more preferably 700 MPa or more, and particularly preferably 1000 MPa or more. If the storage modulus in this temperature range is 500 MPa or more, deformation and damage to the gasket member due to thermocompression during bonding can be prevented.
• the thickness change rate of the base layer in a compression creep test is preferably 30% or less, more preferably 25% or less, and particularly preferably 20% or less.
• the thermal change rate of the base layer in a heat shrinkage test is preferably 0.50% or less, more preferably 0.30% or less, and particularly preferably 0.20% or less.
• the softening point and storage modulus are values determined using a tensile viscoelasticity device (DMS6100 manufactured by Hitachi High-Tech Sanence Corporation). Specifically, the object to be measured is heated from room temperature to 250°C at a frequency of 1 Hz and a heating rate of 2°C/min, and the changes in storage modulus, loss modulus, and tan ⁇ with temperature are recorded.
• the softening point refers to the temperature at which tan ⁇ is at its maximum.
• the melt flow rate of the base layer is preferably 1 g/10 min or more, more preferably 2 g/10 min or more.
• the melt flow rate of the base layer is preferably 50 g/10 min or less, more preferably 30 g/10 min or less. If the melt flow rate of the base layer is below the lower limit, the melt viscosity is high and sheet molding becomes difficult, and if it is above the upper limit, the melt tension is too low and sheet molding also tends to become difficult.
• the melt flow rate of the base layer is a value measured in accordance with JIS K7210:2014 (ISO 1133 2011).
• the melt flow rate of the base layer was measured at a resin temperature of 300°C and a load of 2.16 kg.
• the substrate layer may further include an additive selected from the group consisting of antioxidants, UV absorbers, fillers, reinforcing fibers, release agents, processing aids, flame retardants, plasticizers, nucleating agents, antistatic agents, pigments, dyes, foaming agents, and combinations thereof.
• an additive selected from the group consisting of antioxidants, UV absorbers, fillers, reinforcing fibers, release agents, processing aids, flame retardants, plasticizers, nucleating agents, antistatic agents, pigments, dyes, foaming agents, and combinations thereof.
• the primer layer preferably contains an acid-modified polyolefin or a polycarbonate diol, and more preferably contains an acid-modified polyolefin.
• the content of the acid-modified polyolefin and polycarbonate diol in the primer layer is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more, and may be 100% by mass, based on the total amount of the primer layer.
• the content of the acid-modified polyolefin and polycarbonate diol is within such a range, the effect of improving the adhesion durability of the primer layer is enhanced.
• an acid-modified polyolefin is an unmodified polyolefin (hereinafter also simply referred to as "polyolefin") that has been graft-modified with an acid compound selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic anhydrides, and combinations thereof.
• examples of monomer units constituting the polyolefin include monomer units derived from monomers selected from the group consisting of ⁇ -olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene, diene monomers such as butadiene, isoprene, and chloroprene, aromatic vinyl compounds such as styrene, and combinations thereof.
• ⁇ -olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene
• diene monomers such as butadiene, isoprene, and chloroprene
• aromatic vinyl compounds such as styrene, and combinations thereof.
• polypropylene is particularly preferred.
• Polypropylene is a polymer containing propylene units as the main component, and may be a homopolymer or copolymer, or may be an alloy or blend with other polymer components.
• the content of propylene units is preferably 60% by mass or more, and more preferably 75% by mass or more.
• polypropylene examples include homopolymers such as amorphous polypropylene and crystalline polypropylene, copolymers mainly made of propylene, halogen-modified products such as chlorinated polypropylene, and alloys or blends of polypropylene with other polymers.
• the polypropylene is preferably a copolymer mainly made of propylene, and an example of a copolymer mainly made of propylene is a propylene-1-butene copolymer.
• monomer units constituting polypropylene copolymers or alloys include monomer units derived from monomers selected from the group consisting of ⁇ -olefins such as ethylene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene, diene monomers such as butadiene, isoprene, chloroprene, and diene monomers, aromatic vinyl compounds such as vinyl acetate, (meth)acrylic acid esters, and styrene, and combinations thereof.
• the number of carbon atoms in the monomer is preferably 2 to 10, and more preferably 2 to 5.
• the method for producing polyolefins includes a known method using a polymerization catalyst.
• the polymerization catalyst include Ziegler catalysts and metallocene catalysts
• examples of the polymerization method include slurry polymerization and gas phase polymerization.
• the acid compound used in producing the acid-modified polyolefin is selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic anhydrides, and combinations thereof.
• Unsaturated carboxylic acids are compounds that have an ethylenic double bond and a carboxylic acid group in the same molecule, and examples include various unsaturated monocarboxylic acids and unsaturated dicarboxylic acids. These acid compounds may be used alone or in combination of two or more types.
• unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid.
• unsaturated dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, citraconic acid, nadic acid, and endic acid.
• Unsaturated carboxylic acid anhydrides are compounds that have an ethylenic double bond and a carboxylic acid anhydride group in the same molecule, and examples thereof include the acid anhydrides of the unsaturated dicarboxylic acids mentioned above.
• Specific examples of acid anhydrides of unsaturated dicarboxylic acids include maleic anhydride, fumaric anhydride, itaconic anhydride, citraconic anhydride, nadic anhydride, and endic anhydride.
• maleic acid and maleic anhydride are preferably used because of their high modifying effect, and maleic anhydride is particularly preferably used.
• the acid-modified polyolefin contained in the primer layer is preferably maleic anhydride-modified polyolefin.
• a known method can be used. For example, there is a method in which an acid compound is graft-reacted with a polyolefin in a molten or solution state in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound.
• a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound.
• the temperature for the grafting reaction is preferably 80 to 160°C when the reaction is carried out in a solution state, and 150 to 300°C when the reaction is carried out in a molten state.
• the reaction rate is high at or above the lower limit of the reaction temperature range mentioned above, and the decrease in the molecular weight of the resin can be suppressed at or below the upper limit of the reaction range mentioned above, and the mechanical strength of the resulting acid-modified polyolefin can be maintained.
• the radical polymerization initiator to be used may be selected from commercially available organic peroxides, taking into consideration the reaction temperature, etc.
• the amount of acid compound grafted to the acid-modified polyolefin is preferably 0.2 mass% or more, more preferably 0.4 mass% or more, and particularly preferably 0.6 mass% or more.
• the amount of the grafted acid compound is within such a range, the adhesion of the primer layer can be improved.
• the amount of acid compound grafted to the acid-modified polyolefin is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.
• the amount of grafted acid compound is within such a range, it is possible to suppress the deterioration of physical properties due to a decrease in molecular weight.
• the amount of the acid compound grafted to the acid-modified polyolefin is defined by the following formula based on the acid value of the acid-modified polyolefin.
• Graft amount (mass%) acid value ⁇ M ⁇ 100/(1000 ⁇ 56.1 ⁇ V)
• V valence of acid group (however, in the case of containing an acid anhydride group, this is the valence of the acid group when the acid anhydride group is completely hydrolyzed)
• the acid value indicates the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of a sample, and is measured in accordance with JIS K 0070:1992.
• the melting point of the acid-modified polyolefin is preferably 50°C or higher, and more preferably 60°C or higher. If the melting point of the acid-modified polyolefin is within this range, the heat resistance and adhesive strength at high temperatures of the primer layer can be further improved.
• the melting point of the acid-modified polyolefin is preferably 160°C or less, and more preferably 100°C or less. If the melting point of the acid-modified polyolefin is within this range, good thermocompression bonding properties can be obtained, and the adhesive durability at low temperatures can be improved.
• the melting point refers to the temperature at the top of the endothermic peak that occurs in the process of holding the material at 180°C for several minutes using a differential scanning calorimeter (DSC), then cooling it to 0°C, and then raising the temperature to 200°C at a rate of 10°C per minute.
• DSC differential scanning calorimeter
• the weight average molecular weight (Mw) of the acid-modified polyolefin is preferably 10,000 to 300,000, more preferably 30,000 to 250,000, and even more preferably 50,000 to 200,000.
• acidic polyolefin commercially available products
• examples of commercially available products include “MODIC” manufactured by Mitsubishi Chemical Corporation, “ADMER” and “UNISTOLL” manufactured by Mitsui Chemicals, Inc., “TOYOTAC” manufactured by Toyobo Co., Ltd., “UMEX” manufactured by Sanyo Chemical Industries, Ltd., “REXPERL EAA” and “REXPERL ET” manufactured by Japan Polyethylene Co., Ltd., "PRIMACOL” manufactured by Dow Chemical Co., Ltd., "NUCREL” manufactured by DuPont-Mitsui Polychemicals, and “BONDINE” manufactured by Arkema.
• polycarbonate diols examples include reaction products of low molecular weight diols and/or bisphenols such as bisphenol A with ethylene carbonate or dialkyl carbonates such as dibutyl carbonate.
• Low molecular weight diols include ethylene glycol, propylene glycol, cyclohexanedimethanol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, etc.
• polycarbonate diol commercially available products may be used, such as Duranol T5650J, Duranol T5652, and Duranol G3452 (manufactured by Asahi Kasei Corporation), ETERNACOLL UH-50, ETERNACOLL UH-100 (manufactured by UBE Corporation), Benebiol HS0830B, and Benebiol NL1010DB (manufactured by Mitsubishi Chemical Corporation).
• the primer layer may contain a polymer other than the acid-modified polyolefin and polycarbonate diol described above (hereinafter also referred to as "other polymer B") for the purposes of adhesion, hydrolysis resistance, heat resistance, etc.
• other polymer B a polymer other than the acid-modified polyolefin and polycarbonate diol described above
• the other polymer B may be one type or two or more types.
• polymer B examples include phenolic resin, urea resin, melamine resin, benzoguanamine resin, alkyd resin, unsaturated polyester resin, vinyl ester resin, diallyl terephthalate resin, silicone resin, urethane resin, furan resin, ketone resin, xylene resin, thermosetting polyimide resin, benzoxazine resin, active ester resin, aniline resin, cyanate ester resin, styrene-maleic anhydride (SMA) resin, polyethylene resin, polypropylene resin, polystyrene resin, rubber-modified polystyrene resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, polymethyl methacrylate resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene terephthalate resin, ethylene vinyl alcohol resin, cellulose acetate resin, ionomer resin, poly
• the content of the other polymer B in the primer layer is preferably 0.1% by mass or more, more preferably 1% by mass or more, and particularly preferably 5% by mass or more, based on the total amount of the primer layer.
• the content of the other polymer B is within this range, the improving effect of the other polymer B is enhanced.
• the content of other polymer B in the primer layer is preferably 50% by mass or less, more preferably 35% by mass or less, and particularly preferably 20% by mass or less, based on the total amount of the primer layer.
• the amount added is within such a range, the multilayer sheet can further improve the adhesion, hydrolysis resistance, and heat resistance.
• the primer layer preferably further contains a curing agent.
• the curing agent is preferably a compound capable of forming a crosslinked structure between acidic polyolefins or polycarbonate diols.
• examples of the curing agent include isocyanate compounds, epoxy compounds, carbodiimide compounds, and oxazoline compounds, and it is more preferable that the curing agent is at least one selected from isocyanate compounds and epoxy compounds.
• the isocyanate compound is preferably a compound having two or more isocyanate groups (-NCO) (i.e., a polyfunctional isocyanate compound), and examples thereof include difunctional diisocyanates, and trifunctional or higher isocyanates having a structure such as an adduct structure, an isocyanurate structure, or a biuret structure.
• -NCO isocyanate groups
• isocyanate commercially available products may be used, such as Duranate TPA-100, Duranate T4900-70B, Duranate MFA-75B, Duranate MHG80B, and Duranate 21S-75E (manufactured by Asahi Kasei Corporation), Takenate A-3, Takenate A-50, Takenate 500, Takenate 600, STABIOT D-370N, and STABIOT D-376N (manufactured by Mitsui Chemicals, Inc.).
• Duranate TPA-100 Duranate T4900-70B
• Duranate MFA-75B Duranate MHG80B
• 21S-75E manufactured by Asahi Kasei Corporation
• Takenate A-3 Takenate A-50, Takenate 500, Takenate 600, STABIOT D-370N, and STABIOT D-376N (manufactured by Mitsui Chemicals, Inc.).
• epoxy compounds include bisphenol type epoxy resins such as bisphenol A type epoxy resins (different from hydrogenated bisphenol A type epoxy resins) and bisphenol F type epoxy resins; hydrogenated bisphenol type epoxy resins; novolac type epoxy resins; biphenyl type epoxy resins; stilbene type epoxy resins; hydroquinone type epoxy resins; naphthalene skeleton type epoxy resins; tetraphenylolethane type epoxy resins; trishydroxyphenylmethane type epoxy resins; dicyclopentadiene phenol type epoxy resins; alicyclic epoxy resins such as 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol; and polyglycidyl esters of polybasic acids such as diglycidyl esters of hexahydrophthal
• glycidyl esters glycidyl ethers such as sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polypropylene glycol diglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, and cyclohexanedimethanol diglycidyl ether; diene polymer type epoxy resins such as polybutadiene or polyisoprene; glycidyl amine type epoxy resins such as tetraglycidyldiaminodiphenylmethane, tetraglycidylbisaminomethylcyclohexane, diglycidylan
• epoxy compound commercially available products may be used, and examples thereof include EPICLON HP7200, EPICLON HP4700, EPICLON HP4710 (manufactured by DIC Corporation), jER828, jER157S70 (manufactured by Mitsubishi Chemical Corporation), JP-100, JP-200 (manufactured by Nippon Soda Co., Ltd.), EPPN-501H, NC-7000 (manufactured by Nippon Kayaku Co., Ltd.), TETRAD-C, TETRAD-X (manufactured by Mitsubishi Gas Chemical Co., Ltd.), and the like.
• the amount of hardener to be added can be determined appropriately depending on the type and content of the acidic polyolefin or polycarbonate diol, the type and content of the other polymer B, etc. Only one type of hardener may be used, or two or more types may be used.
• the amount of the isocyanate compound added is preferably 0.1% by mass to 50% by mass, more preferably 5% by mass to 40% by mass, and even more preferably 10% by mass to 35% by mass, relative to the content of the acid-modified polyolefin.
• the adhesive durability of the multilayer sheet is improved, and shape stability tends to be easily obtained.
• the amount of epoxy compound added is preferably 0.1% by mass to 40% by mass, more preferably 1% by mass to 30% by mass, and even more preferably 5% by mass to 20% by mass, relative to the content of the acid-modified polyolefin.
• the adhesive durability of the multilayer sheet tends to be improved and overcuring tends to be easily suppressed.
• additive X an additive selected from imidazole compounds, dioctyl tin laurate, amine compounds, phosphorus compounds, etc.
• additive X may be added to the primer layer.
• Additive X may be a catalyst added in order to promote the reaction of the curing agent.
• additive X The amount of additive X to be added can be determined appropriately depending on the type and amount of curing agent used, the type and amount of acid-modified polyolefin used, etc. Additive X may be used alone or in combination of two or more types.
• the primer layer may further include an additive selected from the group consisting of antioxidants, UV absorbers, fillers, reinforcing fibers, release agents, processing aids, flame retardants, plasticizers, nucleating agents, antistatic agents, pigments, dyes, foaming agents, and combinations thereof.
• an additive selected from the group consisting of antioxidants, UV absorbers, fillers, reinforcing fibers, release agents, processing aids, flame retardants, plasticizers, nucleating agents, antistatic agents, pigments, dyes, foaming agents, and combinations thereof.
• the adhesive layer is a layer that exhibits adhesion to an adherend.
• the adhesive layer is preferably a layer containing at least one selected from polyethylene, polypropylene, an ethylene-propylene copolymer, a styrene-based thermoplastic elastomer, polyester, polyamide, and an acid-modified polyolefin, and more preferably a layer containing an acid-modified polyolefin.
• examples of monomer units constituting the polyolefin include monomer units derived from monomers selected from the group consisting of ⁇ -olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene, diene monomers such as butadiene, isoprene, and chloroprene, aromatic vinyl compounds such as styrene, and combinations thereof.
• the number of carbon atoms in the monomer is preferably 2 to 10, and more preferably 2 to 5.
• polyolefins selected from the group consisting of polymer blends of polyethylene and polypropylene, ethylene-propylene copolymers, and combinations thereof are preferred because they have high adhesive strength to the substrate.
• Polyethylene is a polymer containing ethylene units as the main component, and may be either a homopolymer or a copolymer. When it is a copolymer, the content of ethylene units in the polyethylene is preferably 50% by mass or more, and may be 70% by mass or more.
• Specific examples of polyethylene include homopolymers such as low-density polyethylene, high-density polyethylene, and linear low-density polyethylene; copolymers such as ethylene-diene monomer copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid ester copolymers, and ethylene-methacrylic acid ester copolymers; and halogen-modified products such as chlorinated polyethylene.
• Polypropylene is a polymer containing propylene units as the main component, and may be either a homopolymer or a copolymer. When it is a copolymer, the content of propylene units in the polypropylene is preferably 50% by mass or more, and may be 70% by mass or more. Specific examples of polypropylene include homopolymers such as amorphous polypropylene and crystalline polypropylene, copolymers such as propylene-diene monomer copolymer, and halogen-modified products such as chlorinated polypropylene.
• Ethylene-propylene copolymer is a polymer containing ethylene units and propylene units, and may be composed of only ethylene units and propylene units, or may further contain other monomer units in addition to ethylene units and propylene units.
• An example of an ethylene-propylene copolymer containing other monomer units is an ethylene-propylene-diene monomer copolymer.
• the total amount of ethylene units and propylene units in the ethylene-propylene copolymer is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.
• polyolefins In addition to physical blends of multiple components of these resins, polyolefins also include reactive blends in which functional groups are reacted between different polymers in a molding machine, graft copolymers and block copolymers made of multiple segments, and compositions in which physical blends of these are microdispersed using them as compatibilizers.
• the total amount of ethylene units and propylene units is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.
• the mass ratio of ethylene units to propylene units contained in the polyolefin is preferably 10/90 to 40/60, more preferably 15/85 to 35/65. When the mass ratio of ethylene units is equal to or greater than the lower limit of this range, the thermocompression bondability of the acid-modified polyolefin is improved, and the adhesive strength can be improved.
• the mass ratio of ethylene units is equal to or less than the upper limit of this range, the adhesive strength at high temperatures can be improved.
• the mass ratio of ethylene units to propylene units within the range shown above, it is possible to achieve both adhesive durability at high temperatures and adhesive durability at low temperatures.
• the "mass ratio of ethylene units and propylene units contained in the polyolefin" means the mass ratio of ethylene units and propylene units in all ethylene units and propylene units contained in the polyethylene and polypropylene.
• the mass ratio of ethylene units and propylene units is determined from the absorbance ratio of the characteristic absorption of polyethylene (719 cm -1 ) and the characteristic absorption of polypropylene (1167 cm -1 ) in the IR spectrum. Specifically, a calibration curve is used to convert the absorbance ratio of ethylene units and propylene units to a mass ratio.
• the calibration curve can be created by blending commercially available polyethylene and polypropylene at various ratios and plotting the blending ratio and the absorbance ratio.
• Polyethylene, polypropylene and ethylene-propylene copolymers may contain monomer units other than ethylene units and propylene units.
• monomers that form monomer units other than ethylene units and propylene units include ⁇ -olefins such as 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene, diene monomers such as butadiene, isoprene, and chloroprene, unsaturated carboxylic acids and derivatives thereof such as vinyl acetate, acrylic acid esters, acrylic acid, methacrylic acid, and methacrylic acid esters, and aromatic vinyl compounds such as styrene.
• ⁇ -olefins such as 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene
• diene monomers such as butadiene, isoprene, and chloroprene
• unsaturated carboxylic acids and derivatives thereof such as vinyl acetate, acrylic acid esters
• the content of monomer units other than ethylene units and propylene units in polyolefins is preferably 30% by mass or less, more preferably 20% by mass or less, and particularly preferably 10% by mass or less. If the content of monomer units other than ethylene units and propylene units is within such a range, the properties of the polyolefin such as water resistance, chemical resistance, and durability are improved, and polyolefins can be produced at low cost.
• Manufacturing methods for polyolefins include known manufacturing methods that use polymerization catalysts.
• Polymerization catalysts include Ziegler catalysts and metallocene catalysts, and polymerization methods include slurry polymerization and gas phase polymerization.
• Impact-resistant polypropylene also known as polypropylene block polymer, is essentially a mixture of polypropylene and a propylene-ethylene random copolymer, and can be manufactured by a process consisting of a first step of obtaining a propylene homopolymer and a second step of obtaining a propylene-ethylene random copolymer.
• the weight average molecular weight (Mw) of the acid-modified polyolefin contained in the adhesive layer is preferably 50,000 to 1,000,000, more preferably 100,000 to 750,000, and even more preferably 150,000 to 500,000.
• the melting point of the acid-modified polyolefin is preferably 130°C or higher, and more preferably 135°C or higher. If the melting point of the acid-modified polyolefin is within this range, the heat resistance of the adhesive layer and its adhesive strength at high temperatures can be improved.
• the melting point of the acid-modified polyolefin is preferably 160°C or less, and more preferably 150°C or less. When the melting point of the acid-modified polyolefin is within this range, good thermocompression bonding properties can be obtained, and the adhesive durability at low temperatures can be improved.
• the melt flow rate of the acid-modified polyolefin is preferably 3 g/10 min or more, more preferably 7 g/10 min or more.
• the melt flow rate of the acid-modified polyolefin is preferably 50 g/10 min or less, more preferably 30 g/10 min or less.
• the melt flow rate of the adhesive layer is a value measured in accordance with JIS K7210:2014 (ISO 1133 2011).
• the melt flow rate of the adhesive layer was measured at a resin temperature of 230°C and a load of 2.16 kg.
• the content of the acid-modified polyolefin in the adhesive layer may be 2% by mass or more based on the total amount of the adhesive layer.
• the acid-modified polyolefin may be used in a mixture with an unmodified polyolefin, and when an acid-modified polyolefin with a high degree of acid modification is used, a small amount of about 2% by mass may be used based on the total amount of the adhesive layer.
• the content of the acid-modified polyolefin in the adhesive layer is preferably 30% by mass or more based on the total amount of the adhesive layer, more preferably 70% by mass or more, and particularly preferably 90% by mass or more, and may be 100% by mass.
• Polymers other than acid-modified polyolefins can be added to the adhesive layer for the purpose of improving the adhesive strength at low temperatures, adhesive durability, molding stability, and adhesion to the base layer.
• examples of other polymers C include styrene-butadiene-styrene block copolymers and their hydrogenated products, styrene-isoprene-styrene block copolymers and their hydrogenated products, styrene-isobutylene-styrene block copolymers, and styrene-based graft copolymers in which styrene homopolymers or copolymers are grafted onto polyolefins.
• Unmodified polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers may also be added as other polymers C.
• the lower limit of the content of other polymer C in the adhesive layer is preferably 1 mass% or more, more preferably 2 mass% or more, and particularly preferably 3 mass% or more. When the amount added is within this range, the improving effect of the other polymer C is enhanced.
• the upper limit of the content of other polymer C in the adhesive layer is preferably 50% by mass or less, more preferably 30% by mass or less, and particularly preferably 10% by mass or less.
• the adhesive layer can obtain high heat resistance and high adhesive strength at high temperatures.
• an acid-modified polyolefin with a high degree of acid modification is used, the content of acid-modified polyolefin can be reduced. In such a case, the content of unmodified polyolefin may be high, and the upper limit of the content of unmodified polyolefin in the adhesive composition may be 98% by mass.
• a crosslinkable resin may be added to the adhesive layer, it is preferable that the crosslinkable resin is small or not present at all in the adhesive layer.
• the crosslinkable resin is small, the crystallinity of the acid-modified polyolefin is increased, improving heat resistance and hydrolysis resistance.
• the crosslinkable resin is small, the molecular weight can be prevented from becoming excessively large due to crosslinking, improving the moldability of the adhesive layer.
• the content of the crosslinkable resin in the adhesive layer is preferably less than 3 mass%, more preferably less than 1 mass%, and particularly preferably less than 0.5 mass%, and may be 0 mass%.
• the crosslinkable resin is capable of crosslinking the main component of the adhesive layer, and examples of the crosslinkable resin include resins having multiple functional groups such as phenol novolac-modified epoxy resin, oxazoline group-containing styrene resin, and epoxy group-containing polyolefin resin.
• the adhesive layer may further include an additive selected from the group consisting of antioxidants, UV absorbers, fillers, reinforcing fibers, release agents, processing aids, flame retardants, plasticizers, nucleating agents, antistatic agents, pigments, dyes, foaming agents, and combinations thereof.
• an additive selected from the group consisting of antioxidants, UV absorbers, fillers, reinforcing fibers, release agents, processing aids, flame retardants, plasticizers, nucleating agents, antistatic agents, pigments, dyes, foaming agents, and combinations thereof.
• the substrate layer preferably has a thickness in the range of 10 ⁇ m to 300 ⁇ m, more preferably in the range of 30 ⁇ m to 250 ⁇ m, and particularly preferably in the range of 50 ⁇ m to 200 ⁇ m.
• a thickness of the substrate layer is equal to or greater than this lower limit, sufficient rigidity is obtained.
• the thickness of the substrate layer is equal to or less than this upper limit, the effect on the thickness of the fuel cell incorporating the gasket member can be reduced.
• the primer layer preferably has a thickness in the range of 1 ⁇ m to 20 ⁇ m, more preferably in the range of 5 ⁇ m to 20 ⁇ m, and particularly preferably in the range of 10 ⁇ m to 20 ⁇ m.
• a thickness of the primer layer is equal to or greater than this lower limit, sufficient adhesion is obtained.
• the thickness of the primer layer is equal to or less than this upper limit, the effect on the thickness of the fuel cell incorporating the gasket member can be reduced.
• the adhesive layer preferably has a thickness in the range of 10 ⁇ m to 200 ⁇ m, more preferably in the range of 20 ⁇ m to 150 ⁇ m, and particularly preferably in the range of 30 ⁇ m to 100 ⁇ m.
• the thickness of the adhesive layer is equal to or greater than this lower limit, the occurrence of poor adhesion can be suppressed.
• the thickness of the adhesive layer is equal to or less than this upper limit, the adhesive can be prevented from spilling out of the gasket member, and malfunctions of the fuel cell incorporating the gasket member can be prevented.
• the gasket member and the assembly using it can exhibit excellent adhesive performance, durability, productivity, and cost-effectiveness.
• the total thickness of the gasket member is preferably 30 ⁇ m to 400 ⁇ m, more preferably 50 ⁇ m to 350 ⁇ m, and especially preferably 50 ⁇ m to 300 ⁇ m.
• the thickness of the gasket member and each layer that constitutes the gasket member is the arithmetic average of the thicknesses at three locations measured by preparing a slice having a cross section perpendicular to the main surface of the gasket member and using a VHS-8000 digital microscope (manufactured by Keyence Corporation).
• the base layer and adhesive layer are generally each manufactured from a resin composition as a raw material.
• the resin compositions that are the raw materials for the base layer and adhesive layer are compositions whose main component is resin and are made from the components of the base layer and adhesive layer described above.
• the resin composition that forms the base layer and adhesive layer can be produced by melt-kneading the main resin component and, if necessary, other components in an extruder, Banbury mixer, or heated roll, etc., and then cooling and solidifying the strands extruded from the nozzle holes of the die head while pulling them with water, etc., and cutting them into pellets.
• the temperature for melt-kneading the resin composition used in the base layer is preferably 150°C to 320°C, more preferably 180°C to 300°C, and the kneading time is usually 0.5 minutes to 20 minutes, preferably 1 minute to 15 minutes.
• the temperature for melt-kneading the resin composition used in the adhesive layer is preferably 150°C to 270°C, more preferably 170°C to 250°C, and the kneading time is usually 0.5 minutes to 20 minutes, preferably 1 minute to 15 minutes.
• the substrate layer and adhesive layer can be obtained by molding the resin composition used for the substrate layer and the resin composition used for the adhesive layer thus obtained into a film using a conventional method (e.g., extrusion molding).
• the primer layer is preferably formed on at least one side of the substrate layer by using a coating method. That is, the primer layer is preferably a coating layer.
• the primer layer can be formed by dissolving or dispersing the components of the primer layer described above in a solvent to prepare a primer layer-forming composition, coating the primer layer-forming composition on the substrate layer using a coating means, volatilizing the solvent to form a substrate layer with a coating film, bonding the substrate layer with the coating film obtained to an adhesive layer, and then curing the coating film.
• the solvent may be an organic solvent capable of dissolving or dispersing the components of the primer layer.
• a means for applying the primer layer-forming composition include a bar coater, a spray gun, a dispenser, a roll coater, a curtain coater, and a dip coater.
• the temperature and time for volatilizing the solvent can be set appropriately taking into consideration the type of solvent, etc., and can be, for example, 50°C to 200°C and 0.1 minutes to 5 minutes.
• the gasket member according to the present disclosure has a breaking stress of 50 N/mm2 or more and a breaking elongation of 50% or more, which improves hydrolysis resistance and provides excellent adhesion durability even in a high-temperature and moisture-containing environment.
• the breaking stress is preferably 50 N/mm 2 or more, and more preferably 60 N/mm 2 or more.
• the upper limit of the breaking stress is, for example, 100 N/mm 2 .
• the breaking elongation is preferably 50% or more, and more preferably 60% or more.
• the upper limit of the breaking elongation is, for example, 1,000%.
• the methods for measuring the breaking stress and breaking elongation are as described above.
• the gasket member according to the present disclosure can be manufactured as follows. First, the substrate layer with the coating film and the adhesive layer are each prepared in advance. Next, the surface of the substrate layer on which the coating film is disposed is placed opposite the adhesive layer, and a multi-layer laminate is obtained by thermal lamination. The laminate is then cured to harden the coating, thereby obtaining a gasket member.
• the thermal lamination can be carried out using a known laminator. There are no limitations on the lamination conditions, and general conditions can be applied.
• the lamination temperature is preferably from 50°C to 200°C, and more preferably from 80°C to 150°C.
• the transport speed during lamination is preferably 0.01 m/min to 200 m/min, and more preferably 0.1 m/min to 100 m/min.
• the lamination pressure is preferably from 0.01 MPa to 10 MPa, and more preferably from 0.1 MPa to 5 MPa.
• the coating hardens and a gasket member is obtained in which the base layer, primer layer, and adhesive layer are more firmly bonded.
• the curing conditions are, for example, to leave the laminate at rest for 0.5 to 7 days at a temperature of 40°C to 150°C.
• the gasket member according to the present disclosure can be bonded to an adherend formed of various materials such as metal, glass, ceramics, or plastic. This makes it possible to produce an assembly including the gasket member and the adherend.
• an assembly including the gasket member can be used as a member or part of a layered battery.
• the metal used as the adherend may be a commonly known metal plate, flat metal plate or metal foil, and iron, copper, aluminum, lead, zinc, titanium, chromium, stainless steel, etc. can be used. Among these, iron, aluminum, titanium and stainless steel are particularly preferred.
• thermoplastic or thermosetting resins can be used as the plastic to be used as the adherend.
• Composite materials in which inorganic materials such as glass or ceramics, or fillers or fibers such as metal or carbon are combined with resin can also be used.
• the gasket member according to the present disclosure is for use in a fuel cell, and is a gasket member that is disposed between the electrolyte membrane and the separator of the fuel cell.
• one adhesive layer is disposed on the electrolyte membrane side, and the other adhesive layer is disposed on the separator side.
• Base material Polyimide film (PI film): As the PI film, Upilex 125RN (thickness 125 ⁇ m, manufactured by UBE) was used. ⁇ Polyphenylsulfone film (PPSU film): The PPSU film used was Radel R-5000 (manufactured by Solvay), and a film having a thickness of 70 ⁇ m was produced using a T-die extruder.
• PI film Polyimide film
• PPSU film Polyphenylsulfone film
• Primer layer material ⁇ Acid-modified polyolefin-1 (PO-1) Propylene-butene-1 copolymer, melting point: 70°C, molecular weight: Mw 100,000, maleic anhydride modification rate: 1.1% by mass ⁇ Acid-modified polyolefin-2 (PO-2) Propylene-butene-1 copolymer, melting point 80°C, molecular weight Mw90,000, maleic anhydride modification rate 1.1% by mass ⁇ Polycarbonate diol-1 (PD-1) Duranol T5650J (manufactured by Asahi Kasei Corporation)
• ⁇ Curing Agent> ⁇ Isocyanate compound-1 Duranate TPA-100 (manufactured by Asahi Kasei Corporation) ⁇ Isocyanate compound-2 Duranate T4900-70B (manufactured by Asahi Kasei Corporation) Epoxy compound-1 EPICLON HP-7200 (DIC Corporation)
• Adhesive layer material TM55 (manufactured by Toagosei, Aronmelt (registered trademark) TM55, melting point 142° C.) was used to prepare a film having a thickness of 55 ⁇ m using a T-die extruder.
• Substrate layer Both sides of the substrate were treated with a corona treatment machine (Navidas, Polydyne 1, discharge amount: 81.5 W ⁇ min/m 2 , one round trip).
• Adhesive layer One side (only the surface to be bonded to the primer layer) was treated with a corona treatment machine (Navidas, Polydyne 1, discharge amount: 81.5 W ⁇ min/m 2 , one round trip).
• compositions for forming a primer layer As compositions for forming a primer layer, primer 1 (P-1) to primer 3 (P-3) were prepared as follows.
• Primer 1 (P-1) 67.0 g of polycarbonate diol-1 (PD-1) was dissolved in a mixed solvent of 33.0 g of toluene and 14.9 g of methyl ethyl ketone, and then 30.1 g of isocyanate compound-1 was dissolved therein to obtain primer 1 (P-1).
• Primer 2 (P-2) 14.9 g of acid-modified polyolefin-1 (PO-1) was dissolved in a mixed solvent of 36.2 g of methyl ethyl ketone and 50.8 g of methylcyclohexane at 60° C. under heating, and then 0.3 g of dioctyl tin laurate, 2.4 g of isocyanate compound-1, and 2.4 g of isocyanate compound-2 were dissolved therein to obtain primer 2 (PO-2).
• Primer 3 20.0 g of acid-modified polyolefin-2 (PO-2) was dissolved in a mixed solvent of 35.5 g of toluene, 8.3 g of methyl ethyl ketone, and 82.9 g of methylcyclohexane at 60° C. under heating, and then 2.0 g of epoxy compound-1 and 0.03 g of imidazole compound-1 were dissolved therein to obtain primer 3 (PO-3).
• compositions of Primer 1 (P-1) to Primer 3 (P-3) are summarized in Table 1 below.
• P-1 to P-3 correspond to Primer 1 (P-1) to Primer 3 (P-3), respectively.
• the unit of composition is "g.”
• Example 1 Primer 1 (P-1) was applied to one side of a polyimide film (PI, thickness 125 ⁇ m) with a bar coater to a coating thickness of 10 ⁇ m (dry), and the solvent was evaporated at 100° C. for 1 minute to obtain a coated film (coated substrate layer). Thereafter, the coating surface of the obtained coated film was bonded to TM55 (acid-modified polypropylene film; thickness 55 ⁇ m) by thermal lamination (room temperature (23° C.), 0.3 m/min, 0.3 MPa). Primer 1 (P-1) was also applied to the uncoated side of the PI film in the same manner, and the film was bonded to TM55 to obtain a laminate.
• TM55 room temperature (23° C.), 0.3 m/min, 0.3 MPa
• the resulting laminate was then cured at 60°C for 2 days to harden the coating, thereby obtaining a gasket member (thickness 255 ⁇ m) in which an adhesive layer (thickness 55 ⁇ m)/primer layer (thickness 10 ⁇ m)/base layer (thickness 125 ⁇ m)/primer layer (thickness 10 ⁇ m)/adhesive layer (thickness 55 ⁇ m) were laminated in that order.
• Example 2 Primer 2 (P-2) was applied to one side of a polyimide film (PI, thickness 125 ⁇ m) with a bar coater to a coating thickness of 10 ⁇ m (dry), and the solvent was evaporated at 100° C. for 1 minute to obtain a coated film (coated substrate layer). Thereafter, the coating surface of the obtained coated film was bonded to TM55 (acid-modified polypropylene film; thickness 55 ⁇ m) by thermal lamination (100° C., 0.3 m/min, 0.3 MPa). Primer 2 (P-2) was also applied to the uncoated side of the PI film in the same manner, and the laminate was obtained by bonding with TM55.
• TM55 acid-modified polypropylene film
• the resulting laminate was then cured at 100°C for 4 days to harden the coating, thereby obtaining a gasket member (thickness 255 ⁇ m) in which an adhesive layer (thickness 55 ⁇ m)/primer layer (thickness 10 ⁇ m)/base layer (thickness 125 ⁇ m)/primer layer (thickness 10 ⁇ m)/adhesive layer (thickness 55 ⁇ m) were laminated in that order.
• Example 3 Primer 3 (P-3) was applied to one side of a polyimide film (PI, thickness 125 ⁇ m) with a bar coater to a coating thickness of 10 ⁇ m (dry), and the solvent was evaporated at 100° C. for 1 minute to obtain a coated film (coated substrate layer). Thereafter, the coating surface of the obtained coated film was bonded to TM55 (acid-modified polypropylene film; thickness 55 ⁇ m) by thermal lamination (100° C., 0.3 m/min, 0.3 MPa). Primer 3 (P-3) was also applied to the uncoated side of the PI film in the same manner, and the laminate was obtained by bonding with TM55.
• TM55 acid-modified polypropylene film
• the resulting laminate was then cured at 80°C for 2 days to harden the coating, thereby obtaining a gasket member (thickness 255 ⁇ m) in which an adhesive layer (thickness 55 ⁇ m)/primer layer (thickness 10 ⁇ m)/substrate layer (thickness 125 ⁇ m)/primer layer (thickness 10 ⁇ m)/adhesive layer (thickness 55 ⁇ m) were laminated in that order.
• Example 1 A gasket member (thickness 200 ⁇ m) was obtained in the same manner as in Example 1, except that the polyimide film was changed to a polyphenylsulfone film (PPSU, thickness 70 ⁇ m).
• PPSU polyphenylsulfone film
• Example 2 A gasket member (thickness 200 ⁇ m) was obtained in the same manner as in Example 2, except that the polyimide film was changed to a polyphenylsulfone film (PPSU, thickness 70 ⁇ m).
• PPSU polyphenylsulfone film
• Example 3 A gasket member (thickness 200 ⁇ m) was obtained in the same manner as in Example 3, except that the polyimide film was changed to a polyphenylsulfone film (PPSU, thickness 70 ⁇ m).
• PPSU polyphenylsulfone film
• ⁇ Retention rate of breaking elongation and retention rate of breaking stress The rupture stress (initial rupture stress) and rupture elongation (initial rupture elongation) of the PI film and the PPSU film were measured.
• the PI film and the PPSU film were immersed in water at 120° C. and held for 3000 hours, after which the rupture stress and rupture elongation were measured.
• the measured values were divided by the initial rupture stress and the initial rupture elongation to calculate the rupture stress retention and the rupture elongation retention.
• the rupture stress and rupture elongation were measured by punching out a No.
• Breaking stress retention rate (%) (breaking stress after 3000 hours in water at 120°C ⁇ initial breaking stress) x 100
• Breaking elongation retention rate (%) (breaking elongation after being held in water at 120°C for 3000 hours / initial breaking elongation) x 100
• breaking stress and breaking elongation were measured by punching out a No. 3 dumbbell shape as specified in JIS K 6251, and pulling it with a tensile tester at a pulling speed of 30 mm/min and a gauge length of 20 mm.
• the test environment was 23° C., and the average value of two measurements was used. The results are shown in Table 3.
• the initial peel strength was measured by the hot water peel test described below.
• a SUS304 plate having a thickness of 0.1 mm was used as the adherend, and the gasket member produced in the examples and comparative examples was sandwiched between the SUS304 plates and heat-pressed (180°C, 3 seconds, 1 MPa) with a precision press to produce a bonded body.
• This bonded body was cut into a strip of 10 mm width to prepare a test piece.
• the bonded part of the test piece was 10 mm wide and 15 mm long.
• P-1 to P-3 correspond to primer 1 (P-1) to primer 3 (P-3), respectively.
• the gasket members of the examples in which the base layer contains polyimide has a breaking stress of 50 N/ mm2 or more, and has a breaking elongation of 50% or more, are superior in adhesion durability in high temperature and moisture-containing environments compared to the comparative examples in which the base layer does not contain polyimide.

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