Photocurable resin composition, fuel cell, and sealing method

Abstract

To provide a photocurable resin composition having high curing degree after light irradiation, while maintaining high elongation and high strength cured product characteristics.SOLUTION: A photocurable resin composition contains the following components (A) to (C): component (A): a polyisobutylene resin containing one or more (meth)acryloyl groups and a unit -[CH2C(CH3)2]-, component (B): component (b1): acrylate monomer having alicyclic hydrocarbon group with the carbon number of 5-25, and component (b2): acrylate monomer having a linear or branched alkyl group with the carbon number of 11-30, component (C): a photoradical polymerization initiator.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a photocurable resin composition, a fuel cell, and a sealing method.

Background Art

[0002] In recent years, fuel cells have attracted attention as new energy systems for automobiles and households. A fuel cell is a power generation device that extracts electricity by chemically reacting hydrogen and oxygen. In addition, fuel cells are next-generation clean power generation devices because they have high energy efficiency during power generation and water is generated by the reaction of hydrogen and oxygen. There are four types of fuel cells: polymer electrolyte fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, and solid oxide fuel cells. Among them, polymer electrolyte fuel cells are expected to be used in applications such as power sources for automobiles, home power generation devices, small power sources for electronic devices such as mobile phones, and emergency power sources because they have high power generation efficiency while operating at a relatively low temperature (around 80°C).

[0003] As shown in FIG. 1, the cell 1 of a polymer electrolyte fuel cell has a structure including an electrolyte membrane electrode assembly 5 (MEA) in which a polymer electrolyte membrane 4 is sandwiched between an air electrode 3a and a fuel electrode 3b, a frame 6 that supports the MEA, and a separator 2 in which a gas flow path is formed.

[0004] To start a polymer electrolyte fuel cell, it is necessary to separately supply a fuel gas containing hydrogen to the fuel electrode (anode) 3b and an oxidizing gas containing oxygen to the air electrode (cathode) 3a. This is because if the separation is insufficient and one gas mixes with the other gas, the power generation efficiency may decrease. Against this background, sealants are widely used for the purpose of preventing leakage of fuel gas, oxygen gas, etc. Specifically, seal portions 7 formed using a sealant are arranged between adjacent separators 2, between the separator 2 and the frame 6, between the frame 6 and the polymer electrolyte membrane 4 or the MEA 5, etc.

[0005] As a sealant used in a solid polymer fuel cell, since it is a rubber elastomer excellent in gas barrier properties, low moisture permeability, heat resistance, acid resistance, and flexibility, a heat-curable resin composition obtained by hydrosilylation reaction using a polyisobutylene-based polymer (see Patent Document 1), a heat-curable resin composition obtained by hydrosilylation reaction using a fluoropolyether compound (see Patent Document 2), a heat-curable resin composition obtained by hydrosilylation reaction using a fluoropolymer (see Patent Document 3), and a heat-curable resin composition using ethylene-propylene-diene rubber (see Patent Document 4) have been studied. However, since the heat-curable resin compositions of Patent Documents 1 to 4 require a heating step for curing, there has been a problem that the process time is long. Therefore, a photocurable resin composition capable of shortening the tact time of the curing process has attracted attention. Patent Document 5 discloses a telechelic polyisobutylene polymer having two or three terminal acrylate groups and a polymer composition containing a reactive diluent.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0007] The above-described photocurable resin composition is used for bonding a polymer electrolyte membrane or the like. However, if the degree of curing after light irradiation is low and the reaction is not sufficient, volatile components may be generated from the cured product and adhere to the catalyst layer, which may cause a decrease in power generation performance (see International Publication No. 2009 / 047908 and Japanese Patent Application Laid-Open No. 2009-096413). Further, although the cured product of the polymer composition of Patent Document 5 has cured product characteristics of high elongation and high strength, there is a problem in that the degree of curing after light irradiation is low and volatile components are likely to be generated from the cured product.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide a photocurable resin composition having a high degree of curing after light irradiation while maintaining the cured product characteristics of high elongation and high strength.

Means for Solving the Problems

[0009] The gist of the present invention will be described below.

[0010] [1] A photocurable resin composition comprising the following components (A) to (C): Component (A): A polyisobutylene resin containing one or more (meth)acryloyl groups and -[CH2C(CH3)2]- units Component (B): Component (b1): An acrylate monomer having an alicyclic hydrocarbon group having 5 to 25 carbon atoms and component (b2): An acrylate monomer having a linear or branched alkyl group having 11 to 30 carbon atoms Component (C): A photo radical polymerization initiator.

[0011] [2] The photocurable resin composition according to [1], wherein the component (A) is a polyisobutylene resin represented by the following general formula (1):

[0012]

Chemical formula

[0013] (In the general formula (1), R 1represents a monovalent or polyvalent aromatic hydrocarbon group, or a monovalent or polyvalent aliphatic hydrocarbon group, PIB represents a polyisobutylene backbone containing the above -[CH2C(CH3)2]- unit, and R 4 represents a divalent hydrocarbon group having 2 to 6 carbon atoms, and R 2 and R 3 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R 5 represents a hydrogen atom or a methyl group, and n is an integer of 1 to 6.) [3] The photocurable resin composition according to [1] or [2], which contains 20 to 95 parts by mass of the component (b1) and 3 to 70 parts by mass of the component (b2) with respect to 100 parts by mass of the component (A).

[0014] [4] The component (b1) is one or more selected from the group consisting of cyclohexyl acrylate, trimethylcyclohexyl acrylate, 4-t-butylcyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyacrylate, isobornyl acrylate, and adamantyl acrylate, and the component (b2) is one or more selected from the group consisting of isostearyl acrylate, stearyl acrylate, tridecyl acrylate, lauryl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexyl decyl acrylate, heptadecyl acrylate, and octyl nonyl acrylate. The photocurable resin composition according to any one of [1] to [3].

[0015] [5] A curable sealant for a fuel cell, which contains the photocurable resin composition according to any one of [1] to [4].

[0016] [6] The curable sealant for a fuel cell according to [5], which is a curable sealant for a fuel cell for the periphery of one or more members selected from the group consisting of a separator, a frame, a polymer electrolyte membrane, a fuel electrode, an air electrode, and an electrolyte membrane electrode assembly, which are members in a fuel cell.

[0017] [7] The curable sealing agent for a fuel cell according to [6], wherein the curable sealing agent for a fuel cell is a sealing agent between adjacent separators in a fuel cell or a sealing agent between a frame of a fuel cell and a polymer electrolyte membrane or an electrolyte membrane electrode assembly.

[0018] [8] The curable sealing agent for a fuel cell according to any one of [5] to [7], wherein the curable sealing agent for a fuel cell is a curable sealing agent for a solid polymer fuel cell.

[0019] [9] A cured product obtained by irradiating light on the photocurable resin composition according to any one of [1] to [4] or the curable sealing agent for a fuel cell according to any one of [5] to [8].

[0020]

[10] A fuel cell, wherein a seal portion between adjacent separators in a fuel cell or a seal portion between a frame of a fuel cell and a polymer electrolyte membrane or an electrolyte membrane electrode assembly contains the cured product according to [9].

[0021]

[11] The fuel cell according to

[10] , wherein the fuel cell is a solid polymer fuel cell.

[0022]

[12] A method for sealing at least a part between two flanges, wherein at least one of the flanges is a flange capable of transmitting active energy rays, and the method includes: a step of applying the photocurable resin composition according to any one of [1] to [4] on the surface of one flange; a step of bonding the flange coated with the photocurable resin composition and the other flange through the photocurable resin composition; and a step of irradiating the photocurable resin composition with active energy rays through the flange capable of transmitting active energy rays to cure the photocurable resin composition and seal at least a part between the two flanges.

[0023]

[13] A method for sealing at least a part between two flanges, comprising: applying the photocurable resin composition according to any one of [1] to [4] on the surface of one flange; irradiating the photocurable resin composition with active energy rays to cure the photocurable resin composition, and forming a gasket made of a cured product of the photocurable resin composition on the one flange; placing the other flange on the gasket and pressing the one flange and the other flange through the gasket to seal at least a part between the two flanges.

[0024]

[14] A method for sealing at least a part between two flanges, comprising: placing a gasket forming mold on one flange; injecting the photocurable resin composition according to any one of [1] to [4] into at least a part of the gap between the gasket forming mold and the one flange; irradiating the photocurable resin composition with active energy rays to cure the photocurable resin composition, and forming a gasket made of a cured product of the photocurable resin composition on the one flange; removing the mold from the one flange; placing the other flange on the gasket and pressing the one flange and the other flange through the gasket to seal at least a part between the two flanges.

Advantages of the Invention

[0025] The present invention provides a photocurable resin composition having a high degree of cure after light irradiation while maintaining the cured product characteristics of high elongation and high strength.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0027] One embodiment of the present invention is a photocurable resin composition comprising the following components (A) to (C): Component (A): a polyisobutylene resin containing one or more (meth)acryloyl groups and a -[CH2C(CH3)2]- unit Component (B): Component (b1): an acrylate monomer having an alicyclic hydrocarbon group having 5 to 25 carbon atoms, and Component (b2): an acrylate monomer having a linear or branched alkyl group having 11 to 30 carbon atoms. Component (C): Photoradical polymerization initiator.

[0028] According to the present invention, there is provided a photocurable resin composition that has a high degree of cure after light irradiation while maintaining high elongation and high strength properties of the cured product.

[0029] The details of the invention are described below.

[0030] <Component (A)> The component (A) used in the present invention is not particularly limited as long as it is a polyisobutylene resin having one or more (meth)acryloyl groups and containing -[CH2C(CH3)2]- units (a polymer having a polyisobutylene backbone). As the component (A), for example, it suffices to have -[CH2C(CH3)2]- units (polyisobutylene backbone), and it may be a polymer containing "other constitutional units than -[CH2C(CH3)2]- units". The component (A) appropriately contains, for example, 70% by mass or more, preferably 75% by mass or more, more preferably 80% by mass or more of -[CH2C(CH3)2]- units based on the total amount of the constitutional units. Also, the component (A) appropriately contains, for example, less than 100% by mass, in another embodiment 95% by mass or less, and in yet another embodiment 90% by mass or less of -[CH2C(CH3)2]- units based on the total amount of the constitutional units. The component (A) preferably has 1 to 12, more preferably 2 to 8, still more preferably 2 to 4, and particularly preferably 2 (meth)acryloyl groups. In the present invention, although not bound by theory, the polymer can be defined, for example, as a compound having a structure with repeating units of monomers in the main chain of the polymer and consisting of 100 or more repeating units. Also, the (meth)acryloyl group may be present in either the side chain and / or the terminal of the molecule, but from the viewpoint of excellent high elongation and high strength cured product properties, it is preferably present at the terminal of the molecule.

[0031] As the component (A), a polyisobutylene resin represented by the following general formula (1) is preferable from the viewpoint of obtaining a photocurable resin composition having excellent high elongation and high strength cured product properties. Specific examples of the component (A) include polyisobutylene resins having a (meth)acryloyloxyalkoxyphenyl group. Although the main skeleton of the component (A) in the present invention is a polyisobutylene skeleton, in addition to mainly using isobutylene as the monomer constituting this polyisobutylene skeleton, other monomers may be used for copolymerization as long as the effects of the present invention are not impaired. The component (A) is more preferably liquid at room temperature (25°C) since a photocurable resin composition capable of corresponding to coating by screen printing can be obtained.

[0032]

Chem.

[0033] In general formula (1), R 1 represents a monovalent or polyvalent aromatic hydrocarbon group or a monovalent or polyvalent aliphatic hydrocarbon group, preferably a polyvalent aromatic hydrocarbon group, and particularly preferably a divalent phenylene group. Here, the polyvalent aromatic hydrocarbon group and the polyvalent aliphatic hydrocarbon group respectively refer to a 2- to 6-valent aromatic hydrocarbon group and an aliphatic hydrocarbon group. PIB represents a polyisobutylene skeleton containing (or consisting of) the above -[CH2C(CH3)2]- unit. R 4 represents a divalent hydrocarbon group having 2 to 6 carbon atoms, preferably a divalent hydrocarbon group having 2 or 3 carbon atoms. As the above divalent hydrocarbon group, an alkylene group, an alkenylene group, an alkynylene group, etc. are preferable. The above divalent hydrocarbon group may have any substituent such as a halogen atom, an amino group, a cyano group, a nitro group, a hydroxy group. R 2 and R 3 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably a hydrogen atom. Examples of the above monovalent hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, etc., and these monovalent hydrocarbon groups may have any substituent such as a halogen atom, an amino group, a cyano group, a nitro group, a hydroxy group. R 5 represents a hydrogen atom or a methyl group. n is an integer of 1 to 6, and particularly preferably an integer of 2 to 4. When n is 2 or more, PIB, R 2 、R 3 、R 4 、R 5 may be the same or different from each other.

[0034] The molecular weight of component (A) in the present invention is not particularly limited. However, since it can be applied by screen printing and has excellent cured product properties of high elongation and high strength, the number average molecular weight measured by chromatography is preferably, for example, from 200 to 500,000, more preferably from 1,000 to 100,000, and particularly preferably from 3,000 to 50,000. The number average molecular weight is calculated by the standard polystyrene conversion method using size exclusion chromatography (SEC). When two or more types of component (A) are used in combination, it is preferable that the number average molecular weight of at least one of them is within the above range.

[0035] The viscosity of component (A) in the present invention at 25°C is not particularly limited. However, from the viewpoint of workability and the like, for example, it is 5 Pa·s or more, preferably 50 Pa·s or more, more preferably 100 Pa·s or more, and for example, 3,000 Pa·s or less, preferably 2,500 Pa·s or less, more preferably 2,000 Pa·s or less. The particularly preferred viscosity is 1,750 Pa·s or less. Unless otherwise specified, the viscosity was measured using a cone and plate viscometer at 25°C. When two or more types of component (A) are used in combination, it is preferable that the viscosity of at least one of them is within the above range.

[0036] The production method of the component (A) is not particularly limited, and known methods can be used. For example, the method of reacting a hydroxyl-terminated polyisobutylene with acryloyl chloride or methacryloyl chloride disclosed in Polymer Bulletin, Vol. 6, pp. 135-141 (1981), T.P. Liao and J.P. Kennedy, and Polymer Bulletin, Vol. 20, pp. 253-260 (1988), Puskas et al. can be mentioned. Further, as other production methods of the component (A), there are a method of reacting a hydroxyl-terminated polyisobutylene with a compound having a (meth)acryloyl group and an isocyanate group, a method of reacting a hydroxyl-terminated polyisobutylene with a compound having an isocyanate group and a compound having a (meth)acryloyl group and a hydroxyl group, and a method of reacting a hydroxyl-terminated polyisobutylene with (meth)acrylic acid or a lower (meth)acrylate using a dehydration esterification method or a transesterification method, etc.

[0037] In addition, the production method of the polyisobutylene resin represented by the general formula (1) is not particularly limited, but preferably, a method of reacting a halogen-terminated polyisobutylene with a compound having a (meth)acryloyl group and a phenoxy group represented by the following general formula (2) disclosed in JP-A-2013-216782 can be mentioned. The halogen-terminated polyisobutylene can be obtained by a known method, for example, by cationic polymerization, and more preferably by living cationic polymerization.

[0038]

Chemical formula

[0039] In the general formula (2), R 2 , R 3 , R 4 , and R 5 may be as defined in the general formula (1) above. Specifically, R 4 represents a divalent hydrocarbon group having 2 to 6 carbon atoms. R 2 and R 3each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R 5 represents a hydrogen atom or a methyl group. Examples of the compound represented by the above formula (2) include phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxybutyl (meth) acrylate, phenoxypentyl (meth) acrylate, etc., and preferably phenoxyethyl (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxybutyl (meth) acrylate, phenoxypentyl (meth) acrylate, etc.

[0040] <(Component B)> The (B) component of the present invention is a (b1) component: an acrylate monomer having an alicyclic hydrocarbon group with 5 to 25 carbon atoms and a (b2) component: an acrylate monomer having a linear or branched alkyl group with 11 to 30 carbon atoms. By combining the (b1) component and the (b2) component, a photocurable resin composition with a high degree of cure after light irradiation can be obtained while maintaining the properties of a cured product with high elongation and high strength. Further, by combining the (b1) component and the (b2) component, it exhibits the effect of having a low viscosity and excellent adhesion to PEN used for the frame. The acrylate monomer of the (B) component is preferably monofunctional from the viewpoints of having a low viscosity, excellent adhesion to polyethylene naphthalate (PEN), and excellent properties of a cured product with high elongation and high strength. The (B) component is, for example, a compound represented by H2C=CH-C(=O)-O-R 6 wherein the R 6 which is an alicyclic hydrocarbon group having 5 to 25 carbon atoms corresponds to the (b1) component, and the R 6 which is a linear or branched alkyl group having 11 to 30 carbon atoms corresponds to the (b2) component.

[0041] Examples of the alicyclic hydrocarbon group having 5 to 25 carbon atoms in the component (b1) include a cyclohexyl group, a trimethylcyclohexyl group, a 4-t-butylcyclohexyl group, a dicyclopentanyl group, a dicyclopentenyl group, an isobornyl group, and an adamantyl group. The component (b1) is not particularly limited, and examples thereof include cyclohexyl acrylate, trimethylcyclohexyl acrylate, 4-t-butylcyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, isobornyl acrylate, and adamantyl acrylate. Among them, 4-t-butylcyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, and isobornyl acrylate are preferable. The component (b1) can be used alone or as a mixture of two or more. The commercially available products of the component (b1) are not particularly limited, and examples thereof include SR-506 (isobornyl acrylate, manufactured by Sartomer), FA-513AS (dicyclopentanyl acrylate, manufactured by Showa Denko Materials Co., Ltd.), TBCHA (4-t-butylcyclohexyl acrylate, manufactured by KJ Chemicals Co., Ltd.), and IB-XA (isobornyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.).

[0042] The carbon number of the component (b2) is preferably 25 or less, preferably 23 or less, and more preferably 21 or less. Further, as the component (b2), selecting an acrylate monomer having a linear alkyl group results in even better curability, and selecting an acrylate monomer having a branched alkyl group can yield a cured product with even higher strength. Examples of the component (b2) include isostearyl acrylate, stearyl acrylate, tridecyl acrylate, lauryl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexyl decyl acrylate, heptadecyl acrylate, octyl nonyl acrylate, etc. Among them, isostearyl acrylate, tridecyl acrylate, lauryl acrylate, and tetradecyl acrylate are preferred. The component (b2) can be used alone or as a mixture of two or more. The commercially available products of the component (b2) are not particularly limited, and examples include ISTA (isostearyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.), STA (stearyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.), SR489D (tridecyl acrylate, manufactured by Sartomer Co., Ltd.), LA (lauryl acrylate, manufactured by BASF), L-A (lauryl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.), etc.

[0043] As the blending amount of the component (B), it is preferably included in the range of 20 to 95 parts by mass of the component (b1) and 3 to 70 parts by mass of the component (b2) with respect to 100 parts by mass of the component (A). More preferably, it is included in the range of 30 to 90 parts by mass of the component (b1) and 5 to 60 parts by mass of the component (b2). Even more preferably, it is included in the range of 40 to 85 parts by mass of the component (b1) and 7 to 50 parts by mass of the component (b2). Even more preferably, it is included in the range of 44 to 78 parts by mass of the component (b1) and 9 to 44 parts by mass of the component (b2). By being within the above range, it is possible to further provide a photocurable resin composition having a high curing degree after light irradiation while maintaining the properties of a cured product with low viscosity, high elongation, and high strength. When using a plurality of types of the component (A), it is preferable that the total amount satisfies the above relationship. Similarly, when using a plurality of types of the component (b1) or a plurality of types of the component (b2), it is preferable that the total amount of each satisfies the above relationship.

[0044] <(C) component> The photo radical polymerization initiator of the component (C) used in the present invention is not limited as long as it is a compound that generates radicals by irradiating active energy rays. Here, the active energy rays include all light in a broad sense such as radiation such as α-rays and β-rays, electromagnetic waves such as γ-rays and X-rays, electron beams, ultraviolet rays having a wavelength of about 100 to 400 nm, and visible light having a wavelength of about 400 to 800 nm, and are preferably ultraviolet rays. Examples of the component (C) include acetophenone-based photo radical polymerization initiators, benzoin-based photo radical polymerization initiators, benzophenone-based photo radical polymerization initiators, thioxanthone-based photo radical polymerization initiators, acylphosphine oxide-based photo radical polymerization initiators, titanocene-based photo radical polymerization initiators, etc. Among these, from the viewpoint of obtaining a photocurable resin composition that can be photocured in a short time by irradiating active energy rays, acetophenone-based photo radical polymerization initiators and acylphosphine oxide-based photo radical polymerization initiators are preferable. These may be used alone or in combination of two or more.

[0045] Examples of the acetophenone-based photo radical polymerization initiator include, but are not limited to, diethoxyacetophenone, 1-phenyl-2-hydroxy-2-methylpropan-1-one, benzyldimethylketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer, etc. Commercially available products of the acetophenone-based photo radical polymerization initiator include Omnirad (registered trademark, the same applies hereinafter) 184, Omnirad1173, Omnirad2959, Omnirad127 (manufactured by IGM Resins B.V.), ESACURE (registered trademark) KIP-150 (manufactured by IGM Resins B.V.).

[0046] Examples of the acylphosphine oxide-based photo radical polymerization initiator include, but are not limited to, bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, etc. Commercially available products of the acylphosphine oxide-based photo radical polymerization initiator include OmniradTPO, Omnirad819, Omnirad819DW (manufactured by IGM Resins B.V.).

[0047] The blending amount of the component (C) is not particularly limited, but is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, and particularly preferably 1.1 to 10 parts by mass with respect to 100 parts by mass of the component (A). By being within the above range, it is possible to further provide a photocurable resin composition that can cope with coating by screen printing and can be photocured in a short time. When a plurality of types of component (A) are used, it is preferable that the total amount satisfies the above relationship. Similarly, when a plurality of types of component (C) are used, it is preferable that the total amount satisfies the above relationship.

[0048] <Any component> With respect to the composition of the present invention, within a range that does not impair the object of the present invention, an oligomer or polymer having a (meth)acryloyl group (excluding the component (A) of the present invention), a (meth)acrylate monomer other than the component (B), an inorganic filler, an organic peroxide, a curing accelerator, a storage stabilizer, an antioxidant, a light stabilizer, a plasticizer, a pigment, a flame retardant, and additives such as a surfactant can be used.

[0049] The oligomer or polymer having a (meth)acryloyl group (excluding the component (A) of the present invention) is not particularly limited. For example, urethane (meth)acrylate having a polybutadiene skeleton, urethane (meth)acrylate having a hydrogenated polybutadiene skeleton, urethane (meth)acrylate having a polycarbonate skeleton, urethane (meth)acrylate having a polyether skeleton, urethane (meth)acrylate having a polyester skeleton, urethane (meth)acrylate having a castor oil skeleton, isoprene-based (meth)acrylate, hydrogenated isoprene-based (meth)acrylate, epoxy (meth)acrylate, (meth)acrylic group-containing acrylic polymer, etc. can be mentioned. Among these, since they are excellent in compatibility with the component (A) and the component (B) of the present invention, urethane (meth)acrylate having a polybutadiene skeleton, urethane (meth)acrylate having a hydrogenated polybutadiene skeleton, urethane (meth)acrylate having a castor oil skeleton, isoprene-based (meth)acrylate, hydrogenated isoprene-based (meth)acrylate are preferable. In the present invention, an oligomer refers to a compound having a structure with repeating units of monomers in the main chain and consisting of 2 to 100 repeating units. These may be used alone or in combination of two or more. Also, the (meth)acrylate monomer other than the component (B) may be contained within a range that does not impair the object of the present invention, but when it impairs the object, it is preferably not contained.

[0050] The photocurable resin composition of the present invention may contain an inorganic filler in an amount that does not inhibit storage stability for the purpose of improving the elastic modulus, fluidity, etc. of the cured product. Specifically, examples include inorganic powders, metallic powders, etc. Examples of the inorganic powder filler include glass, fumed silica, alumina, mica, ceramics, silicone rubber powder, calcium carbonate, aluminum nitride, carbon powder, kaolin clay, dried clay minerals, dried diatomaceous earth, etc. The blending amount of the inorganic powder is preferably about 0.1 to 100 parts by mass with respect to 100 parts by mass of the component (A).

[0051] Fumed silica can be blended for the purpose of adjusting the viscosity of the photocurable resin composition or improving the mechanical strength of the cured product. Preferably, those hydrophobically treated with organochlorosilanes, polyorganosiloxanes, hexamethyldisilazane, etc. can be used. Specific examples of fumed silica include commercially available products such as Aerosil (registered trademark) R974, R972, R972V, R972CF, R805, R812, R812S, R816, R8200, RY200, RX200, RY200S, R202 manufactured by Nippon Aerosil Co., Ltd.

[0052] The photocurable resin composition of the present invention may contain an organic peroxide for the purpose of imparting curability by heating or a redox reaction. The use of a redox reaction is preferable because radical species can be generated at room temperature. The organic peroxide is not particularly limited, and examples thereof include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, and acetylacetone peroxide; peroxyketals such as 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)octane, n-butyl-4,4-bis(t-butylperoxy)valerate, and 2,2-bis(t-butylperoxy)butane; hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide; dialkyl peroxides such as di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3; diacyl peroxides such as acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, succinic acid peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and m-toluoyl peroxide;Peroxydicarbonates such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, bis-(4-t-butylcyclohexyl) peroxydicarbonate, dimyristyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, dimethoxyisopropyl peroxydicarbonate, di(3-methyl-3-methoxybutyl) peroxydicarbonate, diallyl peroxydicarbonate; peroxyesters such as t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxypivalate, t-butyl peroxyneodecanoate, cumyl peroxyneodecanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxymaleic acid, t-butyl peroxyisopropyl carbonate, cumyl peroxy octoate, t-hexyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxyneohexanoate, t-hexyl peroxyneohexanoate, cumyl peroxyneohexanoate; and acetylcyclohexylsulfonyl peroxide, t-butyl peroxyallyl carbonate and the like. These organic peroxides may be used alone or in combination of two or more. Among these, cumene hydroperoxide is preferably used from the viewpoint of curability.;

[0053] When an organic peroxide is used in the present invention, a curing accelerator can be blended for the purpose of accelerating the redox reaction. Such a curing accelerator is not particularly limited, but preferably saccharin (o-benzoic sulfimide), hydrazine compounds, amine compounds, mercaptan compounds, transition metal-containing compounds and the like are used.

[0054] Examples of the hydrazine compound include 1-acetyl-2-phenylhydrazine, 1-acetyl-2(p-tolyl)hydrazine, 1-benzoyl-2-phenylhydrazine, 1-(1’,1’,1’-trifluoro)acetyl-2-phenylhydrazine, 1,5-diphenyl-carbohydrazine, 1-formyl-2-phenylhydrazine, 1-acetyl-2-(p-bromophenyl)hydrazine, 1-acetyl-2-(p-nitrophenyl)hydrazine, 1-acetyl-2-(2’-phenylethylhydrazine), ethyl carbazate, p-nitrophenylhydrazine, p-trisulfonyl hydrazide, and the like.

[0055] Examples of the amine compound include 2-ethylhexylamine; heterocyclic secondary amines such as 1,2,3,4-tetrahydroquinaldine; heterocyclic tertiary amines such as quinoline, methylquinoline, quinazoline, quinoxaline, phenazine; aromatic tertiary amines such as N,N-dimethyl-p-toluidine, N,N-dimethylanisidine, N,N-dimethylaniline; azole compounds such as 1,2,4-triazole, oxazole, oxadiazole, thiadiazole, benzotriazole, hydroxybenzotriazole, benzoxazole, 1,2,3-benzothiadiazole, 3-mercaptobenzotriazole, and the like.

[0056] Examples of the mercaptan compound include n-dodecyl mercaptan, ethyl mercaptan, butyl mercaptan, tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane trithioglycolate, pentaerythritol tetrakisthiolglycolate, and the like.

[0057] As the transition metal-containing compound, a metal chelate complex salt is preferably used. For example, iron pentadionate, cobalt pentadionate, copper pentadionate, copper propylenediamine, copper ethylenediamine, iron naphthenate, nickel naphthenate, cobalt naphthenate, copper naphthenate, copper octoate, iron hexoate, iron propionate, vanadium acetylacetonate, etc. can be mentioned.

[0058] The above-mentioned curing accelerator may be used alone or in combination of a plurality. Among these, a mixture of saccharin, a hydrazine-based compound, an amine-based compound and a transition metal-containing compound is more preferable because of its good curing acceleration effect.

[0059] The photocurable resin composition of the present invention may contain a storage stabilizer. As the storage stabilizer, radical absorbers such as benzoquinone, hydroquinone, hydroquinone monomethyl ether, metal chelating agents such as ethylenediaminetetraacetic acid or its disodium salt, oxalic acid, acetylacetone, o-aminophenol, etc. can also be used.

[0060] The photocurable resin composition of the present invention may contain an antioxidant. Examples of the antioxidant include quinone compounds such as β-naphthoquinone, 2-methoxy-1,4-naphthoquinone, methylhydroquinone, hydroquinone, hydroquinone monomethyl ether, mono-t-butylhydroquinone, 2,5-di-t-butylhydroquinone, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, 2,5-di-t-butyl-p-benzoquinone; 2,2-methylenebis(4-methyl-6-t-butylphenol), catechol, t-butylcatechol, 2-butyl-4-hydroxyanisole, 2,6-di-t-butyl-p-cresol, 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate, 4,4'-butylidenebis(6-t-butyl-3-methylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol), 3,9-bis[2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide], benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy, C7-C9 side chain alkyl ester, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 3,3',3",5,5',5"-hexa-t-butyl-a,a',a"-(mesitylene-2,4,6-tolyl)tri-p-cresol, calcium diethyl bis[[3,5-bis(1,1-(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-t-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-t-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, reaction product of N-phenylbenzeneamine and 2,4,6-trimethylpentene, 2,6-di-t-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, phenols such as picric acid; tris(2,4-di-t-butylphenyl)phosphite, tris[2-[[2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]ethyl]amine, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphorous acid, tetrakis(2,4-di-t-butylphenyl)[1,1-biphenyl]-4,4'-diylbisphosphonite, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenz[d,f][1,3,2]dioxaphosphepin and other phosphorus compounds; dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, pentaerythrityl tetrakis(3-laurylthiopropionate), 2-mercaptobenzimidazole and other sulfur compounds; amine compounds such as phenothiazine; lactone compounds; vitamin E compounds and the like. Among them, phenolic compounds are preferred.,

[0061] The photocurable resin composition of the present invention may contain a light stabilizer. Examples of the light stabilizer include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 1-[2-[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl]-4-[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy]-2,2,6,6-tetramethylpiperidine, 1,2,2,6,6-pentamethyl-4-piperidinyl-methacrylate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl] methyl] butyl malonate, bis(2,2,6,6-tetramethyl-1(octyloxy)-4-piperidinyl) decanedioate, the reaction product of 1,1-dimethylethyl hydroperoxide and octane, N,N’,N”,N”’-tetrakis-(4,6-bis-(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) amino)-triazin-2-yl)-4,7-diazadecane-1,10-diamine, the polycondensate of dibutylamine·1,3,5-triazine·N,N’-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly[[6-(1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl) imino]], the polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 2,2,4,4-tetramethyl-20-(β-lauryl oxycarbonyl) ethyl-7-oxa-3,20-diazadispiro[5·1·11·2] heneicosan-21-one, β-alanine-N-(2,2,6,6-tetramethyl-4-piperidinyl)-dodecyl ester / tetradecyl ester, N-acetyl-3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione, 2,2,4,4-Tetramethyl-7-oxa-3,20-diazadispiro〔5,1,11,2〕henicosan-21-one, 2,2,4,4-tetramethyl-21-oxa-3,20-diazadicyclo-〔5,1,11,2〕-henicosane-20-propanoic acid dodecyl ester / tetradecyl ester, propanedioic acid-〔(4-methoxyphenyl)-methylene〕-bis(1,2,2,6,6-pentamethyl-4-piperidinyl) ester, higher fatty acid esters of 2,2,6,6-tetramethyl-4-piperidinol, hindered amine compounds such as 1,3-benzenedicarboxamide, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl); benzophenone compounds such as octabenzone; 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-〔2-hydroxy-3-(3,4,5,6-tetrahydrophthalimido-methyl)-5-methylphenyl〕benzotriazole, 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-t-pentylphenyl)benzotriazole, reaction product of methyl 3-(3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl)propionate and polyethylene glycol, benzotriazole compounds such as 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol; benzoate compounds such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate; triazine compounds such as 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-〔(hexyl)oxy〕phenol and the like. Particularly preferred is a hindered amine compound.,

[0062] The photocurable resin composition of the present invention may contain an adhesion promoter. Examples of the adhesion promoter include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, methacryloxyoctyltrimethoxysilane, vinyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyl-tris(β-methoxyethoxy)silane, γ-chloropropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-ureidopropyltriethoxysilane, hydroxyethyl methacrylate phosphate ester, methacryloxyoxyethyl acid phosphate, methacryloxyoxyethyl acid phosphate monoethylamine half salt, 2-hydroxyethyl methacrylic acid phosphate, and the like. Among these, hydroxyethyl methacrylate phosphate ester, methacryloxyoxyethyl acid phosphate, methacryloxyoxyethyl acid phosphate monoethylamine half salt, 2-hydroxyethyl methacrylic acid phosphate, and the like are preferable. The content of the adhesion promoter is preferably 0.05 to 30 parts by mass, more preferably 0.2 to 10 parts by mass, based on 100 parts by mass of the component (A).

[0063] The photocurable resin composition of the present invention can be produced by a conventionally known method. For example, a predetermined amount of the component (A) to the component (C), and, if necessary, optional components are blended, and using mixing means such as a mixer, it can be produced by mixing preferably at a temperature of 10 to 70 ° C for preferably 0.1 to 5 hours. Also, it is preferable to produce in a light-shielded environment.

[0064] <Coating method> As a method for applying the photocurable resin composition of the present invention to an adherend, for example, methods such as dispensing using an automatic applicator, spraying, inkjet, screen printing, gravure printing, dipping, spin coating, etc. can be used. Among them, the photocurable resin composition of the present invention is optimal for screen printing because it is a photocurable resin composition with a high degree of cure and low viscosity after light irradiation while maintaining the properties of a cured product with high elongation and high strength. Note that the photocurable resin composition of the present invention is preferably liquid at 25°C from the viewpoint of coatability.

[0065] <Curing method> When curing the photocurable resin composition of the present invention by irradiating it with active energy rays such as ultraviolet rays and visible light, the active energy ray source is not particularly limited. For example, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LEDs, fluorescent lamps, sunlight, electron beam irradiation devices, etc. can be mentioned. The irradiation dose of active energy ray irradiation is preferably 3 kJ / m 2 or more, more preferably 5 kJ / m 2 or more, and preferably 70 kJ / m 2 or less, more preferably 60 kJ / m 2 or less, and particularly preferably 50 kJ / m 2 or less from the viewpoint of the tact time of the curing process.

[0066] The photocurable resin composition of the present invention is not particularly limited, but the degree of cure is preferably 75% or more, more preferably 77% or more, and even more preferably 80% or more. Note that the degree of cure is the value measured by the method described in the examples below.

[0067] <Cured product> The cured product of the present invention can be obtained by irradiating the photocurable resin composition of the present invention with active energy rays such as ultraviolet rays by the above curing method. The cured product of the present invention is not limited as long as it is a cured product of the photocurable resin composition of the present invention, regardless of the curing method.

[0068] The cured product of the present invention, or the cured product obtained by curing the photocurable resin composition of the present invention, is not particularly limited, but preferably has a hardness of 3 to 95, more preferably 5 to 90. The hardness of the cured product is the value measured by the method described in the examples below.

[0069] The cured product of the present invention, or the cured product obtained by curing the photocurable resin composition of the present invention, is not particularly limited, but preferably has a tensile strength of 1.2 MPa or more, more preferably 1.7 MPa or more. The tensile strength of the cured product is the value measured by the method described in the examples below.

[0070] The cured product of the present invention, or the cured product obtained by curing the photocurable resin composition of the present invention, is not particularly limited, but preferably has an elongation rate of 310% or more, more preferably 350% or more. The elongation rate of the cured product is the value measured by the method described in the examples below.

[0071] <Use and Sealing Agent> The photocurable resin composition of the present invention or its cured product is preferably used as a curable sealing agent. In the present invention, the sealing agent includes applications such as adhesives, coating agents, casting agents, potting agents, etc. In addition, when used in such applications, the photocurable resin composition of the present invention is preferably liquid at 25°C.

[0072] As specific uses of the sealant, since the photocurable resin composition of the present invention or a cured product thereof is a rubber elastic body excellent in low gas permeability, low moisture permeability, heat resistance, acid resistance, and flexibility, it can be used in fuel cells, solar cells, dye-sensitized solar cells, lithium-ion batteries, electrolytic capacitors, liquid crystal displays, organic EL displays, electronic papers, LEDs, hard disk devices, photodiodes, optical communication / circuits, electric wires / cables / optical fibers, optical isolators, laminates such as IC cards, sensors, substrates, pharmaceuticals / medical instruments / devices, etc. Among these applications, the photocurable resin composition of the present invention is particularly preferably used in fuel cell applications because it cures rapidly upon irradiation with active energy rays such as ultraviolet rays, and the cured product has excellent gas barrier properties.

[0073] <Fuel cell> A fuel cell is a power generation device that generates electricity by chemically reacting hydrogen and oxygen. There are four types of fuel cells: polymer electrolyte fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, and solid oxide fuel cells. Among them, polymer electrolyte fuel cells are used in applications such as power sources for automobiles, home power generation devices, small power sources for electronic devices such as mobile phones, and emergency power sources because they have high power generation efficiency while operating at a relatively low temperature (around 80°C).

[0074] As shown in FIG. 1, a typical cell 1 of a polymer electrolyte fuel cell has a structure including an electrolyte membrane electrode assembly 5 (MEA) in which a polymer electrolyte membrane 4 is sandwiched between an air electrode 3a and a fuel electrode 3b, a frame 6 that supports the MEA 5, and a separator 2 in which gas flow paths are formed. Also, at the start-up of the polymer electrolyte fuel cell, a fuel gas (hydrogen gas) and an oxidizing gas (oxygen gas) are supplied through an oxidizing gas flow path 8a and a fuel gas flow path 8b. Further, cooling water flows through a flow path 9 for the purpose of alleviating heat generation during power generation. Note that a stack of hundreds of these cells packaged together is called a cell stack 10 of a polymer electrolyte fuel cell 11 as shown in FIG. 2.

[0075] When a fuel gas (hydrogen gas) is supplied to the fuel electrode and an oxidizing gas (oxygen gas) is supplied to the oxygen electrode (air electrode), the following reactions occur at each electrode, and overall, a reaction that produces water (H2 + 1 / 2O2 → H2O) occurs. Specifically, protons (H + ) generated at the fuel electrode diffuse through the solid polymer membrane and move to the oxygen electrode side, and the water (H2O) generated by reacting with oxygen is discharged from the oxygen electrode side: Fuel electrode (anode): H2 → 2H + + 2e - Oxygen electrode (cathode): 1 / 2O2 + 2H + + 2e - → H2O.

[0076] To start a solid polymer fuel cell, it is necessary to separately supply a fuel gas containing hydrogen to the anode and an oxidizing gas containing oxygen to the cathode. This is because if the isolation is insufficient and one gas mixes with the other gas, there is a risk of a decrease in power generation efficiency. Against this background, sealants are frequently used for the purpose of preventing leakage of fuel gas, oxygen gas, etc. Specifically, sealants are used between adjacent separators, between a separator and a frame, between a frame and a polymer electrolyte membrane or MEA, etc.

[0077] The sealant of the present invention can be suitably used as a curable sealant for a fuel cell for use around one or more members selected from the group consisting of a separator, a frame, a polymer electrolyte membrane, a fuel electrode, an air electrode, and an electrolyte membrane electrode assembly, which are members in a fuel cell. In particular, the sealant of the present invention can be suitably used as a sealant between adjacent separators in a fuel cell or as a sealant between a frame of a fuel cell and a polymer electrolyte membrane or an electrolyte membrane electrode assembly.

[0078] As the polymer electrolyte membrane 4, a cation exchange membrane having ion conductivity can be mentioned. Preferably, it is chemically stable and strong against operation at high temperatures, and examples include fluorine-based polymers having a sulfonic acid group represented by the following formula (3). As commercially available products, Nafion (registered trademark) manufactured by DuPont, Flemion (registered trademark) manufactured by AGC Inc., Aciplex (registered trademark) manufactured by Asahi Kasei Corporation, etc. can be mentioned. Usually, the polymer electrolyte membrane is a material that is difficult to adhere, but by using the photocurable resin composition of the present invention, it can be adhered.

[0079]

Chemical formula

[0080] The fuel electrode 3b is what is called a hydrogen electrode or an anode, and a known one is used. For example, a carbon supporting a catalyst such as platinum, nickel, or ruthenium can be used. Further, the air electrode 3a is what is called an oxygen electrode or a cathode, and a known one is used. For example, a carbon supporting a catalyst such as platinum or an alloy can be used. A gas diffusion layer that functions to diffuse gas or moisturize the polymer electrolyte membrane may be provided on the surface of each electrode. As the gas diffusion layer, a known one is used, and examples include carbon paper, carbon cloth, and carbon fiber.

[0081] As shown in FIG. 1, the separator 2 has fine uneven flow paths through which fuel gas or oxidizing gas passes and is supplied to the electrodes. The separator 2 is made of aluminum, stainless steel, titanium, graphite, carbon, etc.

[0082] The frame 6 supports and reinforces the polymer electrolyte membrane 4 or MEA 5, which is a thin film, so that they do not break. Examples of the material of the frame 6 include thermoplastic resins such as polyvinyl chloride, polyethylene naphthalate (PEN), polyethylene terephthalate, polypropylene, and polycarbonate. In addition, in order to bond members using the photocurable resin composition of the present invention or a cured product thereof, it is preferable that the members transmit light.

[0083] The fuel cell of the present invention is a fuel cell characterized by being sealed with the photocurable resin composition of the present invention or a cured product thereof. Members that require sealing in a fuel cell include separators, frames, polymer electrolyte membranes, fuel electrodes, air electrodes, MEAs, etc., and a seal portion can be formed between these members. More specific sealing locations (locations where a seal portion is formed) include between adjacent separators, between a separator and a frame, between a frame and a polymer electrolyte membrane or MEA, etc.

[0084] The cured product can be obtained by irradiating the photocurable resin composition of the present invention or the sealant of the present invention with energy rays such as light to cure it. The photocurable resin composition, sealant, or cured product of the present invention can be used as a seal portion around members such as separators, frames, polymer electrolyte membranes, fuel electrodes, air electrodes, and electrolyte membrane electrode assemblies for fuel cells.

[0085] The photocurable resin composition, sealant, or cured product of the present invention can be suitably used for the seal portion between adjacent separators in a fuel cell or the seal portion between the frame of a fuel cell and a polymer electrolyte membrane or an electrolyte membrane electrode assembly.

[0086] Note that the main purpose of the seal between the separator and the frame or between the polymer electrolyte membrane or MEA and the frame is to prevent gas mixing and leakage, and the purpose of the seal between adjacent separators is to prevent gas leakage and leakage of cooling water from the cooling water flow path to the outside. Since the acid generated from the polymer electrolyte membrane creates a strong acid atmosphere, the sealant is required to have acid resistance.

[0087] <Sealing method> The sealing method using the photocurable resin composition of the present invention is not particularly limited, but typically includes the form-in-place gasket (FIPG) method, the cure-in-place gasket (CIPG) method, the mold-in-place gasket (MIPG) method, the liquid injection molding method, and the like.

[0088] The FIPG method is a technique in which a photocurable resin composition is applied to one flange of a component to be sealed by an automatic coating device or the like, and while being bonded to the other flange, active energy rays such as ultraviolet rays are irradiated from the flange side through which light can pass, so that the photocurable resin composition is cured to form an adhesive seal. This method can be used when sealing at least a part between at least two flanges of a component to be sealed having at least two flanges. At this time, at least one of the flanges is capable of transmitting light of active energy rays. This method includes a step of applying the photocurable resin composition of the present invention to at least one surface of the flange, a step of bonding one flange coated with the photocurable resin composition to the other flange via the photocurable resin composition, and a step of irradiating active energy rays through the light-transmissive flange to cure the photocurable resin composition and seal at least a part between the at least two flanges.

[0089] That is, according to one embodiment of the present invention, there is provided a method for sealing at least a part between two flanges, wherein at least one of the flanges is a flange capable of transmitting active energy rays, the method comprising: applying the photocurable resin composition of the present invention to the surface of one of the flanges; bonding the flange coated with the photocurable resin composition and the other flange through the photocurable resin composition; and irradiating the photocurable resin composition with active energy rays through the flange capable of transmitting active energy rays to cure the photocurable resin composition and seal at least a part between the two flanges.

[0090] CIPG is a technique including a step of bead-applying a photocurable resin composition to a flange of a component to be sealed by a screen printing coater, an automatic coater, or the like, irradiating active energy rays such as ultraviolet rays to cure the photocurable resin composition to form a gasket, and a step of bonding with the other flange to perform compression sealing. This method can be used when sealing at least a part between at least two flanges of a component to be sealed having at least two flanges. The method includes: applying the above-described photocurable resin composition to at least one of the flanges; irradiating the applied photocurable resin composition with active energy rays to cure the photocurable resin composition and form a gasket made of a cured product of the photocurable resin composition; placing the other flange on the gasket and crimping the one flange coated with the photocurable resin composition and the other flange through the gasket to seal at least a part between the at least two flanges.

[0091] That is, according to one embodiment of the present invention, there is provided a method for sealing at least a part between two flanges, comprising: applying the photocurable resin composition of the present invention to the surface of one flange; irradiating the photocurable resin composition with active energy rays to cure the photocurable resin composition and form a gasket made of a cured product of the photocurable resin composition on the one flange; placing the other flange on the gasket and pressing the one flange and the other flange through the gasket to seal at least a part between the two flanges.

[0092] MIPG is a method in which a mold made of a material capable of transmitting active energy rays is pressure-bonded to one flange of a component to be sealed in advance, a photocurable resin composition is injected into the cavity formed between the mold and the flange, and active energy rays such as ultraviolet rays are irradiated to photocure and form a gasket, which is then bonded to the other flange and compression-sealed. The mold is preferably made of a light-transmissive material, and specifically, glass, polymethyl methacrylate (PMMA), polycarbonate, cycloolefin polymer, olefin, etc. may be mentioned. Further, in order to facilitate removal from the mold after gasket formation, it is preferable to apply a release agent such as a fluorine-based or silicone-based release agent to the mold in advance. The method can be used when sealing at least a part between at least two flanges of a component to be sealed having at least two flanges. The method includes: arranging a gasket-forming mold on at least one of the flanges; injecting the above-mentioned photocurable resin composition into at least a part of the gap between the gasket-forming mold and the flange on which the mold is arranged; irradiating the photocurable resin composition with the active energy rays to cure the photocurable resin composition and form a gasket made of a cured product of the photocurable resin composition; removing the mold from the one flange; placing the other flange on the gasket and pressing the one flange and the other flange through the gasket to seal at least a part between the at least two flanges.

[0093] That is, according to one embodiment of the present invention, a method for sealing at least a part between two flanges includes: a step of disposing a gasket-forming mold on one of the flanges; a step of injecting the photocurable resin composition of the present invention into at least a part of the gap between the gasket-forming mold and the one flange; a step of irradiating the photocurable resin composition with active energy rays to cure the photocurable resin composition and form a gasket made of a cured product of the photocurable resin composition on the one flange; a step of removing the mold from the one flange; and a step of disposing the other flange on the gasket and crimping the one flange and the other flange via the gasket to seal at least a part between the two flanges. At this time, the gasket-forming mold is preferably capable of transmitting active energy rays.

[0094] Liquid injection molding is a method including flowing a photocurable resin composition into a mold made of a material capable of transmitting light under a specific pressure, irradiating with active energy rays such as ultraviolet rays, and photocuring to form a gasket. Then, one flange is bonded to the other flange via this gasket for compression sealing. Note that the mold is preferably made of a material capable of transmitting light. Specifically, examples include glass, PMMA, polycarbonate, cycloolefin polymer, and olefin. Further, in order to facilitate removal from the mold after gasket formation, it is preferable to apply a release agent such as a fluorine-based or silicone-based release agent to the mold in advance.

Examples

[0095] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0096] <Production of polyisobutylene (a1) having an acryloyloxyethoxyphenyl group> After replacing the inside of a 5 L separable flask with nitrogen, 200 mL of n-hexane and 2000 mL of butyl chloride were added, and the mixture was cooled to -70 °C while stirring under a nitrogen atmosphere. Next, 840 mL (9 mol) of isobutylene, 12 g (0.05 mol) of p-dicumyl chloride, and 1.1 g (0.012 mol) of 2-methylpyridine were added. After the reaction mixture was cooled to -70 °C, 5.0 mL (0.05 mol) of titanium tetrachloride was added to initiate polymerization. Three hours after the start of polymerization, 40 g of phenoxyethyl acrylate (Light Acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.) and 110 ml of titanium tetrachloride were added. Thereafter, stirring was continued at -70 °C for 4 hours, and then 1000 ml of methanol was added to stop the reaction.

[0097] The supernatant was separated from the reaction solution, the solvent and the like were distilled off, the product was dissolved in 3000 ml of n-hexane, washed three times with 3000 ml of pure water, reprecipitated from methanol, and then the solvent was distilled off under reduced pressure. The obtained polymer was vacuum dried at 80 °C for 24 hours to obtain polyisobutylene (a1) having an acryloyloxyethoxyphenyl group.

[0098] The above (a1) contains -[CH2C(CH3)2]- units and contains two acryloyl groups. More specifically, in the general formula (1), R 1 represents a phenylene group, PIB represents a polyisobutylene skeleton, and R 4 represents a hydrocarbon group having 2 carbon atoms, and R 2 and R 3 each independently represent a hydrogen atom, and R 5 is a polymer that is a hydrogen atom. The number average molecular weight (chromatography method, polystyrene conversion) of the (a1) component was 11,100, and the viscosity (25 °C) of the (a1) component was 1550 Pa·s.

[0099] <Preparation of photocurable resin composition> ·Example 1 100 parts by mass of polyisobutylene (a1) having an acryloyloxyethoxyphenyl group as component (A) of the present invention, 78 parts by mass of isobornyl acrylate (IB-XA, manufactured by Kyoeisha Chemical Co., Ltd.) as (b1-1) of component (B), 9 parts by mass of n-lauryl acrylate (L-A, manufactured by Kyoeisha Chemical Co., Ltd.) as (b2-1), and 8 parts by mass of 1-phenyl-2-hydroxy-2-methylpropan-1-one (Omnirad 1173, manufactured by IGM Resins B.V.) as component (C) were added and mixed with a planetary mixer at room temperature (25°C) for 60 minutes under light shielding to obtain Example 1, which is a photocurable resin composition.

[0100] · Example 2 In Example 1, Example 2 was obtained in the same manner as in Example 1, except that (b1-1) was changed to 72 parts by mass and (b2-1) was changed to 16 parts by mass.

[0101] · Example 3 In Example 1, Example 3 was obtained in the same manner as in Example 1, except that (b1-1) was changed to 66 parts by mass and (b2-1) was changed to 22 parts by mass.

[0102] · Example 4 In Example 1, Example 4 was obtained in the same manner as in Example 1, except that (b1-1) was changed to 44 parts by mass and (b2-1) was changed to 44 parts by mass.

[0103] · Example 5 In Example 3, Example 5 was obtained in the same manner as in Example 3, except that dicyclopentanyl acrylate (FA-513AS, manufactured by Showa Denko Materials Co., Ltd.) was used as (b1-2) instead of (b1-1).

[0104] · Example 6 In Example 3, Example 6 was obtained in the same manner as in Example 3, except that 4-t-butylcyclohexyl acrylate (TBCHA, manufactured by KJ Chemicals Co., Ltd.) was used as (b1-3) instead of (b1-1).

[0105] · Example 7 In Example 3, Example 7 was obtained in the same manner as in Example 3, except that isostearyl acrylate (ISTA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was used as (b2-2) instead of (b2-1).

[0106] · Comparative Example 1 In Example 1, Comparative Example 1 was obtained in the same manner as in Example 1, except that (b1-1) was 88 parts by mass and (b2-1) was excluded.

[0107] · Comparative Example 2 In Example 1, Comparative Example 2 was obtained in the same manner as in Example 1, except that (b1-1) was excluded and (b2-1) was 88 parts by mass.

[0108] · Comparative Example 3 In Example 3, Comparative Example 3 was obtained in the same manner as in Example 3, except that isobornyl methacrylate was used instead of (b1-1).

[0109] · Comparative Example 4 In Comparative Example 3, Comparative Example 4 was obtained in the same manner as in Comparative Example 3, except that n-lauryl methacrylate was used instead of (b2-1).

[0110] · Comparative Example 5 In Example 3, Comparative Example 5 was obtained in the same manner as in Example 3, except that phenoxyethyl acrylate was used instead of (b1-1).

[0111] The following tests (1) to (4) were conducted on the photocurable resin compositions prepared in each example and comparative example. The results are shown in Table 1 below. The test methods used in the examples and comparative examples in Table 1 are as follows. It was determined that it was suitable if at least all of the following (1) to (4) passed.

[0112] (1) Curing degree confirmation test The degree of cure was measured by measuring the reduction rate of acryloyl or methacryloyl groups in the photocurable resin composition before and after irradiation with light using FT-IR (Spectrum 100, manufactured by Perkin Elmer). The reduction rate was measured by measuring the change in the wavelength of 1635 cm from the baseline in the FT-IR measurement chart of the photocurable resin composition layer before irradiation with light. -1 The absorption peak (absorption peak of the CH2=CH2- group) height (P1) of the photocurable resin composition after irradiation with light was measured. The difference between the absorption peak height (P1) of the photocurable resin composition after irradiation with light and the difference between the absorption peak height (P1) of the photocurable resin composition after irradiation with light -1 The absorption peak height (P2) of the photocurable resin composition was calculated by substituting the absorption peak height (P2) of the photocurable resin composition into the following formula (1). 2 The results are shown in Table 1. A degree of cure of 75% or more is considered acceptable, more preferably 77% or more, and particularly preferably 80% or more.

[0113] Curing degree (%)=((P1-P2) / P1)×100 ···(1) (2) Hardness measurement The thickness of the photocurable resin composition was set to 1 mm, and the cumulative light dose was 45 kJ / m 2 The specimen was cured by irradiating it with ultraviolet light at 1000 kJ / s to produce a sheet-like cured product. The pressure surface of an A-type durometer (hardness tester) was pressed with a force of 10 N while being kept parallel to the test piece (six sheets of cured product stacked together, set to a thickness of 6 mm), and the pressure surface was pressed against the sample to bring the specimen into close contact with the pressure surface. The maximum value was read during the measurement and recorded as the "hardness." The results are shown in Table 1. Details are in accordance with JIS K 6253 (2012). A hardness of 3 to 95 is considered acceptable, with a hardness of 5 to 90 being more preferable.

[0114] (3) Tensile strength measurement The thickness of the photocurable resin composition was set to 1 mm, and the cumulative light dose was 45 kJ / m 2It was irradiated with ultraviolet rays and cured to produce a sheet-like cured product. A test piece was produced by punching with a No. 3 dumbbell. Both ends of the test piece were fixed to the chuck so that the major axis of the test piece and the center of the chuck were in a straight line. The test piece was pulled at a tensile speed of 500 mm / min, and the maximum load was measured. The strength at the maximum load was defined as the "tensile strength (MPa)". The results are shown in Table 1. Details follow JIS K 6251 (2010). In the present invention, from the viewpoint of high strength, if the tensile strength is 1.2 MPa or more, it is considered qualified, and 1.7 MPa or more is more preferable.

[0115] (4) Measurement of elongation rate of cured product The thickness of the photocurable resin composition was set to 1 mm, and it was irradiated with ultraviolet rays of an integrated light amount of 45 kJ / m 2 and cured to produce a sheet-like cured product. A test piece was produced by punching with a No. 3 dumbbell, and marking lines at 20 mm intervals were marked on the test piece.

[0116] It was fixed to the chuck in the same manner as in the measurement of tensile strength, and pulled at a tensile speed of 500 mm / min until the test piece was cut. Since the test piece elongated and the interval between the marking lines widened during the measurement, the interval between the marking lines was measured with calipers until the test piece was cut. Based on the initial interval between the marking lines, the ratio of elongation was defined as the "elongation rate (%)". Evaluation was carried out based on the following criteria, and the results are shown in Table 1. In terms of high extensibility, if the elongation rate is 310% or more, it is considered qualified, and 350% or more is more preferable.

[0117]

Table 1

[0118] According to Examples 1 to 7 in Table 1, it can be seen that the present invention can provide a photocurable resin composition having a high degree of cure after light irradiation while maintaining the cured product characteristics of high elongation and high strength.

[0119] Further, Comparative Example 1 in Table 1 is a photocurable resin composition that does not contain (b2-1) of component (B) of the present invention, but the result is inferior in that it is not a cured product with high elongation. Further, Comparative Example 2 is a photocurable resin composition that does not contain (b1-1) of component (B) of the present invention, but the result is inferior in that it is not a cured product with high elongation and high strength. Further, Comparative Example 3 is a photocurable resin composition using a methacrylate monomer having an alicyclic hydrocarbon group instead of component (b1) of component (B) of the present invention, but the degree of curing is inferior. Comparative Example 4 is a photocurable resin composition using a methacrylate monomer having an alicyclic hydrocarbon group instead of component (b1) of component (B) of the present invention and using a methacrylate monomer having a linear or branched alkyl group instead of component (b2), but the degree of curing is inferior. Further, Comparative Example 5 is a photocurable resin composition using an acrylate monomer having an aromatic ring instead of component (b1) of component (B) of the present invention, but it is not compatible with component (A) of the present invention and separates, so that the test could not be conducted.

[0120] Furthermore, (5) an adhesion test to PEN and (6) a viscosity measurement were performed. The results are shown in Table 2.

[0121] (5) Adhesion test to PEN The photocurable resin compositions of Examples 1 to 7 and Comparative Examples 1 to 5 were applied to a PEN test piece having a width of 25 mm × a length of 100 mm × a thickness of 1.6 mm, and then the same PEN test pieces were bonded and fixed so as to have a width of 25 mm × a length of 10 mm. After that, the integrated light amount was 45 kJ / m 2The test specimens were prepared by irradiating with ultraviolet rays and curing the photocurable resin composition. Both ends of the test specimens were fixed, and the strength at the maximum load measured by tensile measurement at a tensile speed of 10 mm / min was defined as the adhesive strength (MPa) to PEN. The results are shown in Table 2. In the present invention, from the viewpoint of excellent adhesive strength to PEN used for the frame, if the adhesive strength is 0.8 MPa or more, it is considered qualified, and more preferably 1.0 MPa or more. Note that although the results of Comparative Examples 3 and 4 in Table 2 are stated as uncured, it means that the test could not be conducted because they were not cured. In Comparative Example 5, the test could not be conducted because they were not compatible. Note that as the PEN, a member that transmits light was used.

[0122] (6) Viscosity measurement The viscosity (Pa·s) of each photocurable resin composition was measured using a rheometer HAAKE MARS3 manufactured by Thermo Fisher Scientific Co., Ltd. based on the following measurement conditions. In the present invention, from the viewpoint of excellent screen printability and adhesion to the polymer electrolyte membrane, if the viscosity is 50 Pa·s or less, it is considered qualified, more preferably 20 Pa·s or less, and particularly preferably 10 Pa·s or less. Note that in Comparative Example 5, the test could not be conducted because they were not compatible.

[0123] Measurement conditions Shear rate 10 (1 / s) Temperature 25°C.

[0124]

Table 2

[0125] According to Examples 1 to 7 in Table 2, it can be seen that the present invention has excellent adhesion to PEN used for the frame and has a low viscosity. Further, in Comparative Example 1, which is a photocurable resin composition not containing (b2-1) of component (B) of the present invention, there was no problem with the adhesion to PEN, but in Comparative Example 2, which is a photocurable resin composition not containing (b1-1), the adhesion to PEN was poor. Further, Comparative Example 3 is a photocurable resin composition using a methacrylate monomer having an alicyclic hydrocarbon group instead of component (b1) of component (B) of the present invention, but it was uncured. Comparative Example 4 is a photocurable resin composition using a methacrylate monomer having an alicyclic hydrocarbon group instead of component (b1) of component (B) of the present invention and using a methacrylate monomer having a linear or branched alkyl group instead of component (b2), and the result was that it was uncured. Further, Comparative Example 5 is a photocurable resin composition using an acrylate monomer having an aromatic ring instead of component (b1) of component (B) of the present invention, but it was not compatible with component (A) of the present invention and separated, so that the test could not be performed.

[0126] Furthermore, tests on (7) water vapor transmission rate (water vapor barrier property) and (8) hydrogen gas barrier property were conducted.

[0127] (7) Water vapor transmission rate (water vapor barrier property) The photocurable resin composition of Example 2 was poured into a frame of 200 mm × 200 mm × 1.0 mm. Then, ultraviolet rays were irradiated for 20 seconds with an integrated light amount of 45 kJ / m 2 so as to obtain a sheet-like cured product with a thickness of 1.0 mm. 5 g of anhydrous calcium chloride was placed in an aluminum cup having an opening with a diameter of 30 mm, and the cup was set to cover the cured product. After measuring the "initial total weight" (g), it was left in a constant temperature and humidity chamber maintained at an atmospheric temperature of 40°C and a relative humidity of 95% RH for 24 hours, and the "total weight after standing" (g) was measured, and the water vapor transmission rate (g / m 2 ·24 h) was calculated and evaluated based on the following evaluation criteria. The results are shown in Table 3. The detailed test method conformed to JIS Z 0208. In addition, the water vapor transmission rate is 10 g / m when used as a curable sealant for fuel cells. 2·Preferably less than 24 hours.

[0128] [Evaluation Criteria] Pass: The water vapor transmission rate is 10 g / m 2 ·Less than 24 hours Fail: The water vapor transmission rate is 10 g / m 2 ·24 hours or more.

[0129] (8) Hydrogen gas barrier property test Using the photocurable resin composition of Example 2, ultraviolet light was irradiated for 20 seconds with an integrated light amount of 45 kJ / m 2 to prepare a sheet-like cured product with a thickness of 1.0 mm. Next, using the obtained sheet-like cured product, the hydrogen gas barrier property was measured in accordance with JIS K7126-1:2006 (Plastics - Films and Sheets - Gas Permeability Test Methods - Part 1: Differential Pressure Method). The type of test was the pressure sensor method, and the conditions were measured at 23°C with the test gas (hydrogen gas) on the high-pressure side at 100 kPa, and evaluated based on the following evaluation criteria. The results are shown in Table 3. Note that the hydrogen gas barrier property, when used as a photocurable sealant for fuel cells, is preferably less than 1×10 -15 mol·m / m 2 ·s·Pa.

[0130] [Evaluation Criteria] Pass: 1×10 -15 mol·m / m 2 ·s·Pa or less Fail: 1×10 -15 mol·m / m 2 ·s·Pa or more.

[0131] [Table 3]

[0132] According to Example 2 in Table 3, it can be seen that the present invention has low water vapor transmission rate, excellent hydrogen gas barrier property, and good sealing property. [Industrial Applicability]

[0133] The present invention has been made in view of the above circumstances. Since it is a photocurable resin composition having a high degree of cure after light irradiation while maintaining the properties of a cured product with high elongation and high strength, it can be used for various sealing applications. In particular, it is industrially useful because it is effective as a curable sealant for fuel cells.

Explanation of Signs

[0134] 1 Cell of a solid polymer fuel cell 2 Separator 3a Air electrode (cathode) 3b Fuel electrode (anode) 4 Polymer electrolyte membrane 5 Membrane electrode assembly (MEA) 6 Frame 7 Seal part 8a Oxidizing gas flow path 8b Fuel gas flow path 9 Cooling water flow path 10 Cell stack 11 Solid polymer fuel cell

Claims

1. A curable sealant for fuel cells for use around one or more members selected from the group consisting of a separator, a frame, a polymer electrolyte membrane, a fuel electrode, an air electrode, and an electrolyte membrane electrode assembly, which is a member in a fuel cell and contains the following components (A) to (C): The photocurable resin composition contains 30 to 90 parts by mass of component (b1) and 5 to 60 parts by mass of component (b2) with respect to 100 parts by mass of component (A), and is a curable sealant for fuel cells: (A) component: having one or more (meth)acryloyl groups and a -[CH ２ C(CH ３ ) ２ -unit, and a polyisobutylene resin represented by the following general formula (1) 【Chemical 1】 (In the general formula (1), R1 represents a monovalent or polyvalent aromatic hydrocarbon group or a monovalent or polyvalent aliphatic hydrocarbon group, PIB represents a polyisobutylene skeleton containing the -[CH2C(CH3)2]- unit, R4 represents a divalent hydrocarbon group having 2 to 6 carbon atoms, R2 and R3 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, R5 represents a hydrogen atom or a methyl group, and n is an integer of 1 to 6.) Component (B): Component (b1): An acrylate monomer having an alicyclic hydrocarbon group having 5 to 25 carbon atoms and Component (b2): An acrylate monomer having a linear or branched alkyl group having 11 to 30 carbon atoms Component (C): A photo radical polymerization initiator.

2. The photocurable resin composition contains 44 to 78 parts by mass of component (b1) and 9 to 44 parts by mass of component (b2) with respect to 100 parts by mass of component (A), and is the curable sealant for fuel cells according to Claim 1.

3. Component (b1) is one or more selected from the group consisting of cyclohexyl acrylate, trimethylcyclohexyl acrylate, 4-t-butylcyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyacrylate, isobornyl acrylate, and adamantyl acrylate, Component (b2) is one or more selected from the group consisting of isostearyl acrylate, stearyl acrylate, tridecyl acrylate, lauryl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexyl decyl acrylate, heptadecyl acrylate, and octyl nonyl acrylate, and is the curable sealant for fuel cells according to Claim 1 or 2. **Claim 4**: The component (b1) is one or more selected from the group consisting of 4-t-butylcyclohexyl acrylate, dicyclopentanyl acrylate, and isobornyl acrylate, the component (b2) is one or more selected from the group consisting of isostearyl acrylate and lauryl acrylate, and the curable sealant for fuel cells according to any one of Claims 1 to 3. **Claim 5** The curable sealant for fuel cells according to any one of Claims 1 to 4, wherein the curable sealant for fuel cells is a sealant between adjacent separators in a fuel cell or a sealant between a frame of a fuel cell and a polymer electrolyte membrane or an electrolyte membrane electrode assembly. **Claim 6**: The curable sealant for fuel cells is a sealant between a frame of a fuel cell and a polymer electrolyte membrane or an electrolyte membrane electrode assembly, and the material of the frame is one or more selected from the group consisting of polyvinyl chloride, polyethylene naphthalate (PEN), polyethylene terephthalate, polypropylene, and polycarbonate. The curable sealant for fuel cells according to Claim 5. **Claim 7**: The curable sealant for fuel cells according to Claim 6, wherein the material of the frame is polyethylene naphthalate (PEN). **Claim 8** The curable sealant for fuel cells according to any one of Claims 1 to 7, wherein the curable sealant for fuel cells is a curable sealant for a solid polymer fuel cell. **Claim 9** A cured product obtained by irradiating the curable sealant for fuel cells according to any one of Claims 1 to 8 with light. **Claim 10** A fuel cell, wherein a seal portion between adjacent separators in a fuel cell or a seal portion between a frame of a fuel cell and a polymer electrolyte membrane or an electrolyte membrane electrode assembly contains the cured product according to Claim 9. **Claim 11** The fuel cell according to Claim 10, wherein the fuel cell is a solid polymer fuel cell. **Claim 12** A method of sealing at least a part between two flanges, wherein at least one of the flanges is a flange capable of transmitting active energy rays, a step of applying the curable sealant for fuel cells according to any one of Claims 1 to 8 to the surface of one flange; and a step of bonding the flange coated with the curable sealant for fuel cells and the other flange through the curable sealant for fuel cells. A step of irradiating the curable sealant for a fuel cell with active energy rays through a flange capable of transmitting the active energy rays to cure the curable sealant for a fuel cell and sealing at least a part between the two flanges; A method comprising the above.

13. A method of sealing at least a part between two flanges, comprising: A step of applying the curable sealant for a fuel cell according to any one of claims 1 to 8 to the surface of one flange; A step of irradiating the curable sealant for a fuel cell with active energy rays to cure the curable sealant for a fuel cell and forming a gasket made of a cured product of the curable sealant for a fuel cell on the one flange; A step of placing the other flange on the gasket and crimping the one flange and the other flange via the gasket to seal at least a part between the two flanges; A method comprising the above.

14. A method of sealing at least a part between two flanges, comprising: A step of placing a gasket forming mold on one flange; A step of injecting the curable sealant for a fuel cell according to any one of claims 1 to 8 into at least a part of the gap between the gasket forming mold and the one flange; A step of irradiating the curable sealant for a fuel cell with active energy rays to cure the curable sealant for a fuel cell and forming a gasket made of a cured product of the curable sealant for a fuel cell on the one flange; A step of removing the mold from the one flange; A step of placing the other flange on the gasket and crimping the one flange and the other flange via the gasket to seal at least a part between the two flanges; A method comprising the above.

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