Photocurable resin composition, fuel cell and sealing method

Abstract

To provide a photocurable resin composition which is excellent in low out gas property of a cured product and prevents elution of a phosphorus element.SOLUTION: A photocurable resin composition contains the following components (A) to (C), and 1 to 20 pts.mass of the component (C) with respect to 100 pts.mass of the component (A). Component (A): polyisobutylene resin containing one or more (meth)acryloyl groups and a -[CH2C(CH3)2]- unit. Component (B): isobornyl (meth)acrylate. Component (C): ketal-based photoradical polymerization initiator.SELECTED DRAWING: None

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, household 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 a sealant used in polymer electrolyte fuel cells, a polyisobutylene-based polymer photocurable resin composition is known because it is a rubber elastic body excellent in gas permeability resistance, low moisture permeability, heat resistance, acid resistance, and flexibility (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, resin compositions used in solid polymer fuel cells have been required to suppress outgassing during and after curing. However, when a photoinitiator with low reactivity is used, outgassing occurs. Therefore, when a photoinitiator with high reactivity is used to suppress outgassing, there is a problem that when the cured product comes into contact with water generated during power generation of the fuel cell, phosphorus elements elute, reducing the power generation efficiency of the fuel cell.

[0006] The present invention has been made in view of the above situation, and an object thereof is to provide a photocurable resin composition that provides a cured product having both low outgassing properties of the cured product and no elution of phosphorus elements. [Means for Solving the Problems]

[0007] [1] A photocurable resin composition containing the following components (A) to (C), The photocurable resin composition contains 1 to 20 parts by mass of component (C) with respect to 100 parts by mass of component (A). Component (A): A polyisobutylene resin containing one or more (meth)acryloyl groups and -[CH2C(CH3)2]- units Component (B): Isobornyl (meth)acrylate Component (C): A ketal-based photo radical polymerization initiator [2] The photocurable resin composition according to [1], wherein the component (C) is a benzyl ketal-based photo radical polymerization initiator. [3] The photocurable resin composition according to claim 1, wherein the component (C) is 2,2-dimethoxy-2-phenylacetophenone. [4] The photocurable resin composition according to [1], further comprising, as component (D), a (meth)acrylate monomer having a linear or branched alkyl group having 5 to 30 carbon atoms (excluding the component (B)). [5] The photocurable resin composition according to [1], containing 30 to 130 parts by mass of component (B) with respect to 100 parts by mass of component (A). [6] The photocurable resin composition according to [1], characterized by not containing an acylphosphine-based photo radical polymerization initiator. [7] A sealing agent comprising the photocurable resin composition according to any one of [1] to [6]. [8] A cured product obtained by irradiating the photocurable resin composition according to any one of [1] to [6] or the sealing agent according to [7] with light. [9] A fuel cell including any one of the group consisting of a seal between adjacent separators in a fuel cell, a seal between a frame of the fuel cell and an electrolyte membrane, and a seal between the frame of the fuel cell and an electrolyte membrane electrode assembly, wherein any one of the seals is the cured product described in [8].

[10] A method for sealing at least a portion of a gap between at least two flanges of a sealed part having at least two flanges, the method comprising the steps of: applying the photocurable resin composition described in any one of [1] to [6] 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; and placing the other flange on the gasket and crimping the one flange to which the photocurable resin composition has been applied and the other flange via the gasket to seal at least a portion of the gap between the at least two flanges. Effect of the Invention

[0008] The present invention provides a photocurable resin composition that gives a cured product that has both low outgassing properties and no elution of phosphorus element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] One embodiment of the present invention comprises the following components (A) to (C): A photocurable resin composition comprising 1 to 20 parts by mass of component (C) per 100 parts by mass of component (A). Component (A): Polyisobutylene resin containing one or more (meth)acryloyl groups and a -[CH2C(CH3)2]- unit (B) Component: Isobornyl (meth)acrylate (C) Component: Ketal-based photoinitiator According to the present invention, a photocurable resin composition is provided that gives a cured product having both low outgassing properties and no elution of phosphorus element. The details of the invention will be described below. In this specification, "X to Y" is used to mean including the numerical values (X and Y) described before and after as the lower limit value and the upper limit value, and means "X or more and Y or less". Also, in the present invention, (meth)acrylate means both acrylate and methacrylate.

[0010] <(A) Component> The (A) component 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 skeleton). As the (A) component, for example, it may have -[CH2C(CH3)2]- units (polyisobutylene skeleton), and may be a polymer containing "other constitutional units other than -[CH2C(CH3)2]- units". The (A) component preferably contains -[CH2C(CH3)2]- units in an amount of, for example, 70% by mass or more, preferably 75% by mass or more, more preferably 80% by mass or more, based on the total amount of the constitutional units. Also, the (A) component preferably contains -[CH2C(CH3)2]- units in an amount of, for example, less than 100% by mass, in another embodiment 95% by mass or less, and in another embodiment 90% by mass or less, based on the total amount of the constitutional units. The (A) component 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, a polymer can be defined, for example, as a structure having 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 obtaining a photocurable resin composition that gives a cured product excellent in low outgassing properties, it is preferably present at the terminal of the molecule.

[0011] 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 that gives a cured product excellent in low outgassing 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 copolymerized as long as the effects of the present invention are not impaired. Since a photocurable resin composition with good dischargeability from a dispenser can be obtained for the component (A), it is preferably liquid at normal temperature (25°C).

[0012]

Chemical formula

[0013] In the 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, particularly preferably a divalent phenylene group. At this time, the polyvalent aromatic hydrocarbon group and the polyvalent aliphatic hydrocarbon group each refer to a 2- to 6-valent aromatic hydrocarbon group and aliphatic hydrocarbon group, respectively. PIB represents a polyisobutylene skeleton containing the -[CH2C(CH3)2]- unit (or consisting of the -[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 3each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably a hydrogen atom. The monovalent hydrocarbon group includes 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, etc. R 5 represents a hydrogen atom or a methyl group. n is an integer of 1 to 6, 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.

[0014] The molecular weight of the component (A) in the present invention is not particularly limited, but from the viewpoint of obtaining a photocurable resin composition having more excellent sealing properties, the number average molecular weight by chromatographic measurement is, for example, preferably 200 to 500,000, more preferably 1,000 to 100,000, and particularly preferably 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 kinds 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.

[0015] The viscosity of the component (A) in the present invention at 25°C is not particularly limited, but since a photocurable resin composition having good dischargeability from a dispenser can be obtained, 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, 3000 Pa·s or less, preferably 2500 Pa·s or less, more preferably 2000 Pa·s or less. The particularly preferred viscosity is 1750 Pa·s or less. Unless otherwise specified, the viscosity was measured using a cone plate viscometer at 25°C. When two or more kinds of component (A) are used in combination, it is preferable that the viscosity of at least one of them is within the above range.

[0016] The production method of the component (A) is not particularly limited, and known methods can be used. For example, the method of reacting hydroxyl-terminated polyisobutylene 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. with acryloyl chloride or methacryloyl chloride can be mentioned. Further, as other production methods of the component (A), a method of reacting hydroxyl-terminated polyisobutylene with a compound having a (meth)acryloyl group and an isocyanate group, a method of reacting hydroxyl-terminated polyisobutylene with a compound having an isocyanate group and a compound having a (meth)acryloyl group and a hydroxyl group, a method of reacting hydroxyl-terminated polyisobutylene with (meth)acrylic acid or a lower ester of (meth)acrylic acid using a dehydration esterification method or a transesterification method, etc. can be mentioned.

[0017] Further, 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 disclosed in JP-A-2013-216782 with a compound having a (meth)acryloyl group and a phenoxy group represented by the following general formula (2) 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.

[0018]

Chemical formula

[0019] 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.

[0020] <(Component B)> The (B) component of the present invention is isobornyl (meth)acrylate. By including the (B) component, the generation of outgas of the cured product can be suppressed. Further, it is preferable to include 30 to 130 parts by mass of the (B) component, more preferably 40 to 120 parts by mass, and most preferably 50 to 110 parts by mass with respect to 100 parts by mass of the (A) component. By including 30 parts by mass or more of the (B) component, the generation of outgas of the cured product can be suppressed, and by including 130 parts by mass or less, a photocurable resin composition excellent in sealing properties can be obtained. Further, from the viewpoint of further suppressing the generation of outgas of the cured product, isobornyl acrylate is preferable.

[0021] The commercially available products of the (B) component are not particularly limited, and examples include SR-506 (isobornyl acrylate, manufactured by Arkema), IB-XA (isobornyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.), etc.

[0022] <(Component C)> The (C) component of the present invention is a ketal-based photo radical polymerization initiator. A ketal is an ether synthesized from a ketone, and R 8 -C(OR 6 )(OR 7 )-R 9 (wherein the R 6 ~R 9It is an organic compound represented by (an organic group). By irradiating active energy rays, radicals are generated from the component (C) and the photocurable resin composition of the present invention can be cured. Here, the active energy rays include all light in a broad sense such as radiation like α-rays and β-rays, electromagnetic waves like γ-rays and X-rays, electron beams, ultraviolet rays with a wavelength of about 100 to 400 nm, visible light with a wavelength of about 400 to 800 nm, etc., and are preferably ultraviolet rays. By containing 1 to 20 parts by mass of the component (C) with respect to 100 parts by mass of the component (A), a photocurable resin composition capable of suppressing the elution of phosphorus element from the cured product can be obtained. Also, from the viewpoint of being more excellent in low outgassing property, a benzyl ketal-based photo radical polymerization initiator is preferable. Benzyl ketal refers to a ketal synthesized from benzyl which is an aromatic diketone. Also, from the viewpoint of being more excellent in low outgassing property from the cured product, it is preferable to contain 1 to 10 parts by mass of the component (C) with respect to 100 parts by mass of the component (A), and most preferably 1 to 5 parts by mass. Also, a photo radical initiator other than the component (C) may be used in combination. When a photo radical initiator other than the component (C) is used in combination, from the viewpoint of the low outgassing property of the cured product, the content of the photo radical initiator other than the component (C) is preferably 50% by mass or less, more preferably 30% by mass or less, and further preferably 10% by mass or less in 100% by mass of the total photo radical polymerization initiator containing the component (C). The lower limit value is 0% by mass. Also, from the viewpoint of being excellent in suppressing the elution of phosphorus element from the cured product, it is preferably substantially free of an acylphosphine-based photo radical polymerization initiator. Here, being substantially free means that the content of the acylphosphine-based photo radical polymerization initiator is 1% by mass or less in 100% by mass of the total photo radical polymerization initiator containing the component (C). The lower limit value is 0% by mass.

[0023] Examples of the acylphosphine-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-based photo radical polymerization initiator include LUCIRIN TPO, IRGACURE819, IRGACURE819DW (manufactured by BASF), etc.

[0024] The commercially available products of the component (C) are not particularly limited, and examples thereof include Omnirad651 (2,2-dimethoxy-2-phenylacetophenone, manufactured by IGM Resins B.V.).

[0025] <Component (D)> Furthermore, the present invention may contain, as component (D), a (meth)acrylate monomer having a linear or branched alkyl group with 5 to 30 carbon atoms, provided that component (D) excludes the aforementioned component (B). By including component (D), the cured product is more excellent in low outgassing property. Examples of the linear or branched alkyl group with 5 to 30 carbon atoms contained in component (D) include linear alkyl groups such as n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, lauryl group (n-dodecyl group), n-tridecyl group, myristyl group (n-tetradecyl group), n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, stearyl group (n-octadecyl group), n-nonadecyl group, n-icosyl group, etc.; branched alkyl groups such as 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylpropyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, 1-methylpentyl group, 4-methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, 1-methylhexyl group, 2-ethylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethylpentyl group, 1-propylbutyl group, 1-ethyl-1,2-dimethylpropyl group, 1-methylheptyl group, 1-ethylhexyl group, 1-propylpentyl group, 2-propylpentyl group, isononyl group (7-methyloctyl group), 1-methyloctyl group, 2,2-dimethylheptyl group, 1-ethylheptyl group, 3-ethylheptyl group, 1-propylhexyl group, 1-butylpentyl group, 1-methylnonyl group, 1-ethyloctyl group, 1-propylheptyl group, 1-butylhexyl group, isostearyl group, etc. Also, from the viewpoint of making the cured product more excellent in low outgassing property, component (D) is preferably an acrylate monomer having a linear or branched alkyl group with 5 to 30 carbon atoms.

[0026] The carbon number of the component (D) is preferably 25 or less, preferably 22 or less, more preferably 19 or less, and particularly preferably 15 or less. On the other hand, the lower limit of the carbon number is preferably 6 or more, more preferably 7 or more, particularly preferably 8 or more, and most preferably 9 or more. The component (D) is not particularly limited, and examples thereof include isostearyl (meth) acrylate, stearyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octyl nonyl (meth) acrylate, etc. Among them, isostearyl acrylate, tridecyl acrylate, lauryl acrylate, and tetradecyl acrylate are preferred. The component (D) can be used alone or as a mixture of two or more kinds.

[0027] There is no particular limitation on the commercially available products of the component (D), and examples thereof 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), LA (lauryl acrylate, manufactured by BASF), L-A (lauryl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.), etc.

[0028] The blending amount of the component (D) is not particularly limited. For example, it is 1 to 60 parts by mass, preferably 2 to 50 parts by mass, more preferably 3 to 35 parts by mass, and particularly preferably 4 to 20 parts by mass with respect to 100 parts by mass of the component (A). Further, with respect to 100 parts by mass of the component (A), the total mass of the component (D) and the component (B) is 30 to 190 parts by mass, preferably 40 to 170 parts by mass, and more preferably 50 to 130 parts by mass. The blending mass ratio of the component (B) and the component (D) is not particularly limited. For example, (B) component:(D) component is 99:1 to 60:40, preferably 97:3 to 70:30, and preferably 95:5 to 80:20. By being within the above range, a photocurable resin composition excellent in the low outgassing property of the cured product can be further provided.

[0029] <Optional component> For the photocurable resin composition of the present invention, within a range not impairing the object of the present invention, an oligomer or polymer having a (meth)acryloyl group (not including the component (A) of the present invention), a (meth)acrylate monomer (not including the component (B) and the component (D) of the present invention), a filler, an organic peroxide, a curing accelerator, a storage stabilizer, an antioxidant, an antifoaming agent, a dispersant, a polymerization inhibitor, a light stabilizer, an adhesion promoter, a plasticizer, a pigment, a flame retardant, and additives such as a surfactant can be used. Further, it is preferable that a compound containing a phosphorus element is substantially not contained from the viewpoint of phosphorus element elution. Here, "substantially" means 0.2% by mass or less, more preferably 0.05% by mass or less, and still more preferably 0.01% by mass or less in 100% by mass of the total photocurable resin composition.

[0030] The oligomer or polymer having the (meth)acryloyl group (not including 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. The blending amount of the oligomer or polymer having the (meth)acryloyl group is not particularly limited, but is 5 to 300 parts by mass, more preferably 20 to 150 parts by mass, and particularly preferably 30 to 50 parts by mass with respect to 100 parts by mass of the component (A). By being within the above range, it is possible to provide a photocurable resin composition capable of obtaining a cured product having even more excellent low outgassing properties.

[0031] Examples of the (meth)acrylate monomer other than the component (B) and the component (D) include a (meth)acrylate monomer having a linear or branched alkyl group with 1 to 4 carbon atoms or 31 or more carbon atoms, and a (meth)acrylate monomer having an alicyclic hydrocarbon group other than the component (B). The (meth)acrylate monomer other than the component (B) and the component (D) may be contained within a range not impairing the object of the present invention, but in order to more remarkably obtain the effect of the present invention, it is preferable that these components are not contained. That is, the photocurable resin composition according to the present invention preferably substantially does not contain a (meth)acrylate monomer other than the component (B) and the component (D). Here, the term "substantially" means 0.2% by mass or less, more preferably 0.05% by mass or less, and still more preferably 0.01% by mass or less in 100% by mass of the entire photocurable resin composition.

[0032] For the present invention, for the purpose of improving the elastic modulus, fluidity, etc. of the cured product, a filler may be added to such an extent that the storage stability is not impaired. Specifically, organic powders, inorganic powders, metallic powders, etc. can be mentioned. Examples of the filler of the inorganic powder 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). If it is 0.1 part by mass or more, a sufficient effect can be expected, and if it is 100 parts by mass or less, the fluidity of the photocurable resin composition can be sufficiently maintained and a certain workability can be maintained, which is preferable.

[0033] 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, for example, commercially available products such as Aerosil R974, R972, R972V, R972CF, R805, R812, R812S, R816, R8200, RY200, RX200, RY200S, R202, etc. manufactured by Nippon Aerosil.

[0034] The photocurable resin composition of the present invention may contain an organic peroxide for the purpose of imparting curability by heating or 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; Peroxy esters 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.;

[0035] In the present invention, a curing accelerator can be blended. 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.

[0036] 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-trisulfonylhydrazide, and the like.

[0037] 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, ethyl 4-(dimethylamino)benzoate; morpholine tertiary amines such as 2(dimethylamino)2(4methylbenzyl)1(4morpholinophenyl)butan1one; azole compounds such as 1,2,4-triazole, oxazole, oxadiazole, thiadiazole, benzotriazole, hydroxybenzotriazole, benzoxazole, 1,2,3-benzothiadiazole, 3-mercaptobenzotriazole, and the like.

[0038] 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.

[0039] 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. may be mentioned.

[0040] The above-mentioned curing accelerator may be used alone or in combination of two or more. Among these, saccharin, hydrazine-based compounds, amine-based compounds, and transition metal-containing compounds are more preferable because of their good curing acceleration effect.

[0041] 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.

[0042] 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, the reaction product of N-phenylbenzenamine 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]dioxaphosphefin-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]dioxaphosphefin 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.,

[0043] The photocurable resin composition of the present invention may contain an antifoaming agent. By containing an antifoaming agent, generation of bubbles during coating can be suppressed, and the sealing property of the photocurable resin composition of the present invention can be improved. The antifoaming agent is not particularly limited, but for example, mineral oil-based, polyether-based, and silicone-based antifoaming agents are used, and silicone-based antifoaming agents are preferably used. The amount of the antifoaming agent used is not particularly limited, but from the viewpoint of the low outgassing property of the cured product, it is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, and even more preferably 3 to 6 parts by mass with respect to 100 parts by mass of the component (A).

[0044] The photocurable resin composition of the present invention may contain a dispersant. By containing a dispersant, the viscosity can be adjusted to an arbitrary value and the workability can be improved. From the viewpoint of ease of handling when preparing the photocurable resin composition, it is preferably liquid at room temperature. Examples of the dispersant include polyether compounds, carboxylic acid amide compounds, hydroxycarboxylic acid amide compounds (including polyhydroxycarboxylic acid amide compounds), urea urethane amide compounds, and polyvinylpyrrolidone, polysaccharide derivatives (such as guar gum and xanthan gum), benzyl alcohol, xylene, ethanol, terpene, and mixtures of one or more of them.

[0045] The dispersant is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, and even more preferably 0.15 to 1 part by mass with respect to 100 parts by mass of the component (A). By being 0.01 part by mass or more, the viscosity and thixotropy can be improved, and by being 5 parts by mass or less, generation of outgas from the cured product of the present invention can be suppressed.

[0046] 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)-triazine-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〕heneicosan-21-one, 2,2,4,4-tetramethyl-21-oxa-3,20-diazadicyclo-〔5,1,11,2〕-heneicosan-20-propanoic acid dodecyl / tetradecyl ester, propane dioic 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 series such as 1,3-benzenedicarboxamide, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl); benzophenone series 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 series compounds such as 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol; benzoate series compounds such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate; triazine series 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 series compound.,

[0047] The photocurable resin composition of the present invention may contain an adhesion promoter. Examples of the adhesion promoter include 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, (meth)acryloxyoctyltrimethoxysilane, 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 (meth)acrylate phosphate, (meth)acryloxyoxyethyl acid phosphate, (meth)acryloxyoxyethyl acid phosphate monoethylamine half salt, 2-hydroxyethyl (meth)acrylate phosphate, and the like. Among these, hydroxyethyl (meth)acrylate phosphate, (meth)acryloxyoxyethyl acid phosphate, (meth)acryloxyoxyethyl acid phosphate monoethylamine half salt, 2-hydroxyethyl (meth)acrylate 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).

[0048] It is preferable to add a polymerization inhibitor to the present invention. Specific examples of the polymerization inhibitor include organic polymerization inhibitors such as hydroquinone, tert-butylhydroquinone, hydroquinone monomethyl ether, 2,6-di-tert-butyl-4-methylphenol, 2,4,6-tri-tert-butylphenol, 4-tert-butylcatechol, benzoquinone, phenothiazine, N-nitroso-N-phenylhydroxylamine ammonium, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and dibutylhydroxytoluene; inorganic polymerization inhibitors such as copper chloride, copper sulfate, and iron sulfate; and organic salt polymerization inhibitors such as copper dibutyldithiocarbamate and aluminum salt of N-nitroso-N-phenylhydroxylamine. The polymerization inhibitor is preferably contained in an amount of 0.01 to 1 part by mass, more preferably 0.08 to 0.5 part by mass, and most preferably 0.1 to 0.3 part by mass based on 100 parts by mass of the component (A). By blending the polymerization inhibitor in an amount within the above range, the storage stability and curability of the curable resin composition can be maintained well.

[0049] The photocurable resin composition of the present invention can be produced by a conventionally known method. For example, predetermined amounts of the components (A) to (C) are blended, and if necessary, predetermined amounts of the component (D) and / or optional components are also blended, and then 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. Further, it is preferable to produce it in a light-shielded environment.

[0050] <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 coater, spraying, inkjet, screen printing, gravure printing, dipping, and spin coating can be used. Among them, since the photocurable resin composition of the present invention is excellent in sealing property and has a low viscosity, it is most suitable for dispensing. In addition, from the viewpoint of coatability, the photocurable resin composition of the present invention is preferably liquid at 25°C.

[0051] <Hardening 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 or less, more preferably 60 kJ / m or less, and particularly preferably 50 kJ / m or less from the viewpoint of the tact time of the curing process. 2 or less, more preferably 60 kJ / m 2 or less, and particularly preferably 50 kJ / m 2 or less.

[0052] <Cured product> The cured product of the present invention is obtained by curing the photocurable resin composition of the present invention by irradiating it with active energy rays such as ultraviolet rays by the above-mentioned 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. 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 the hardness measured by a Type A durometer (hardness tester) is preferably 3 to 95, and more preferably 5 to 90.

[0053] <Use and sealant> The use for which the photocurable resin composition of the present invention is preferably used is a sealant. In the present invention, the sealant includes uses such as adhesives, coating agents, casting agents, potting agents, etc. When used in such applications, the photocurable resin composition of the present invention is preferably liquid at 25°C.

[0054] As specific uses of the sealant, since the photocurable resin composition of the present invention or its cured product is a rubber elastic body excellent in low gas permeability, low moisture permeability, heat resistance, acid resistance, and flexibility, fuel cells, solar cells, dye-sensitized solar cells, lithium-ion batteries, electrolytic capacitors, liquid crystal displays, organic EL displays, electronic paper, LEDs, hard disk devices, photodiodes, optical communication / circuits, electric wires / cables / optical fibers, optical isolators, laminated bodies such as IC cards, sensors, substrates, pharmaceuticals / medical instruments / devices, etc. can be mentioned. Among these uses, the photocurable resin composition of the present invention is particularly preferable for fuel cells, hard disk devices, liquid crystal displays, and organic EL displays because the cured product has excellent low outgassing properties and excellent sealing properties, and the use for fuel cells is most preferable because phosphorus elements do not elute from the cured product.

[0055] <Fuel cell> A fuel cell is a power generation device that generates electricity by chemically reacting hydrogen and oxygen. In addition, 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 for 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).

[0056] When fuel gas (hydrogen gas) is supplied to the fuel electrode and oxidizing gas (oxygen gas) is supplied to the oxygen electrode (air electrode), the following reactions occur at each electrode, and overall, a reaction (H2 + 1 / 2O2 → H2O) in which water is generated occurs. Specifically, the protons (H + ) generated at the fuel electrode diffuse through the polymer electrolyte 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

[0057] To start a polymer electrolyte 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 separation is insufficient and one gas mixes with the other, it may cause 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. The sealant of the present invention can be suitably used as a curable sealant for a fuel cell 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 a 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 a membrane electrode assembly.

[0058] 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. As members that require sealing in a fuel cell, there are 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 the 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. By irradiating the photocurable resin composition of the present invention or the sealant of the present invention with energy rays such as light and curing it, a cured product thereof can be obtained. The photocurable resin composition, sealant, or cured product thereof 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. The photocurable resin composition, sealant, or cured product thereof 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. Note that the main purpose of sealing "between a separator and a frame" or "between a polymer electrolyte membrane or MEA and a frame" is to prevent gas mixing and leakage, and the purpose of sealing between adjacent separators is to prevent gas leakage and prevent cooling water from leaking to the outside from the cooling water flow path. Since it becomes a strong acid atmosphere due to the acid generated from the polymer electrolyte membrane, the sealant is required to have acid resistance.

[0059] <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, cure-in-place gasket (CIPG) method, mold-in-place gasket (MIPG) method, liquid injection molding method, etc. Note that in this specification, "sealing" means closing, and "sealant" means a sealing material. The sealant is sometimes called a "gasket".

[0060] The FIPG method is a technique for adhesively sealing by applying a photocurable resin composition to one flange of a component to be sealed using an automatic coating device or the like, irradiating active energy rays such as ultraviolet rays from the flange side capable of transmitting light in a state where it is bonded to the other flange, and curing the photocurable resin composition. 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. The 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 and the other flange via the photocurable resin composition, and a step of irradiating the photocurable resin composition with active energy rays through the flange capable of transmitting the active energy rays to cure the photocurable resin composition and seal at least a part between the at least two flanges. 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, and the method includes a step of applying the photocurable resin composition of the present invention to the surface of one flange, a step of bonding the flange coated with the photocurable resin composition and the other flange via the photocurable resin composition, and a step of irradiating the photocurable resin composition with active energy rays through the flange capable of transmitting the active energy rays to cure the photocurable resin composition and seal at least a part between the two flanges.

[0061] CIPG is a method that includes a step of bead-applying a photocurable resin composition onto the flange of a component to be sealed using a screen printing coater, an automatic coater, or the like, irradiating the photocurable resin composition with active energy rays such as ultraviolet rays to cure the photocurable resin composition and form a gasket, and a step of bonding and compression-sealing with the other flange. 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 a step of applying the above-described photocurable resin composition onto at least one of the flanges, irradiating the applied photocurable resin composition with active energy rays to cure the photocurable resin composition, forming a gasket made of the 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 via the gasket to seal at least a part between the at least two flanges. That is, according to one embodiment of the present invention, there is provided a method for sealing at least a part between two flanges, the method including a step of applying the photocurable resin composition of the present invention onto the surface of one flange, irradiating the photocurable resin composition with active energy rays to cure the photocurable resin composition, forming a gasket made of the cured product of the photocurable resin composition on the one flange, 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.

[0062] MIPG is a method in which a mold made of a material capable of transmitting active energy rays is press - contacted in advance with one flange of the component to be sealed, 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, and then bonded to the other flange for compression sealing. The mold is preferably made of a material that can transmit light. Specifically, glass, polymethyl methacrylate (PMMA), polycarbonate, cycloolefin polymer, olefin, etc. can be mentioned. Also, 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. 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 a step of disposing a gasket - forming mold on at least one of the flanges, a step of 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 disposed, a step of irradiating the photocurable resin composition with the active energy rays to cure the photocurable resin composition and form a gasket made of the cured product of the photocurable resin composition, a step of removing the mold from the one flange, a step of disposing 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.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: arranging a gasket-forming mold on one flange; 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; irradiating the photocurable resin composition with active energy rays to cure the photocurable resin composition and form a gasket made of the cured product of the photocurable resin composition on the one flange; removing the mold from the one flange; arranging 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. At this time, it is preferable that the gasket-forming mold is transmissive to active energy rays.

[0063] Liquid injection molding is a method including flowing a photocurable resin composition into a mold made of a light-transmissive material under a specific pressure, irradiating with active energy rays such as ultraviolet rays to photocure and form a gasket. Then, one flange is bonded to the other flange through this gasket for compression sealing. The mold is preferably made of a light-transmissive material. Specifically, examples include glass, PMMA, polycarbonate, cycloolefin polymer, olefin, etc. Also, 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

[0064] Examples are given below to explain the present invention in more detail, but the present invention is not limited to these examples.

[0065] <Preparation of Photocurable Resin Composition> Each component was taken in the parts by mass shown in Table 1 and mixed with a planetary mixer at room temperature (25°C) for 60 minutes under light shielding to obtain a photocurable resin composition. The detailed addition amounts follow Table 1, and all numerical values are expressed in parts by mass.

[0066] <Production of polyisobutylene (a1) having an acryloyloxyethoxyphenyl group> After purging the inside of the container 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. Then, after stirring was continued at - 70 °C for 4 hours, 1000 mL of methanol was added to stop the reaction. The supernatant was separated from the reaction solution, and after distilling off the solvent and the like, 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.

[0067] The above - mentioned a1 contains - [CH2C(CH3)2] - units and contains two acryloyl groups. More specifically, in general formula (1), R 1 represents a phenylene group, PIB represents a polyisobutylene skeleton, R 4 represents a hydrocarbon group having 2 carbon atoms, 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 (by chromatography method, polystyrene conversion) of the a1 component is 11,100, and the viscosity (25 °C) of the a1 component was 1550 Pa·s.

[0068] <Component (A) and comparative component> a1: Polyisobutylene having an acryloyloxyethoxyphenyl group a’1: Terminal acrylated hydrogenated polyisoprene (UC-102 manufactured by Kuraray Co., Ltd.) a’2: Adduct-based urethane acrylate (UN-2601 manufactured by Negami Kogyo Co., Ltd.) <(Component (B) and comparative components)> b1: Isobornyl acrylate (IBX-A manufactured by Kyoeisha Chemical Co., Ltd.) b’1: Dicyclopentenyl acrylate (FA-511AS manufactured by Hitachi Chemical Co., Ltd.) <(Component (C) and comparative components)> c1: 2,2-Dimethoxy-2-phenylacetophenone (Omnirad 651 manufactured by IGM Resins B.V.) c’1: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (Omnirad TPO manufactured by IGM Resins B.V.) c’2: Oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone (KIP150 manufactured by lamberti) c’3: 2-Hydroxy-2-methylpropiophenone (Omnirad1173 manufactured by IGM Resins B.V.) c’4: 4’-(2-Hydroxyethoxy)-2-methylpropiophenone (Omnirad2959 manufactured by IGM Resins B.V.) c’5: 3-Ketocoumarin (Esacure 3644 manufactured by IGM Resins B.V.) c’6: 2,4-Diethylthioxanthone-9-one (JRCure-1106 manufactured by Tianjin Jiuri New Materials Co., Ltd.) c’7: Methyl benzoylformate (Omnirad MBF manufactured by IGM Resins B.V.) <(Component (D))> d1: Lauryl acrylate (L-A manufactured by Kyoeisha Chemical Co., Ltd.) <Optional component> Curing accelerator: Ethyl 4-(dimethylamino)benzoate (JRCure-1101 manufactured by Tianjin Jiuri New Materials Co., Ltd.) Curing accelerator: 2(Dimethylamino)2(4Methylbenzyl)1(4Morpholinophenyl)butan1one (JRCure-1118 manufactured by Tianjin Jiuri New Materials Co., Ltd.) Defoaming agent: silicone-based defoaming agent (BYK-1799 manufactured by BYK-Chemie) Dispersant: polyhydroxycarboxylic acid amide compound (BYK-405 manufactured by BYK Chemie Japan)

[0069] For the photocurable resin compositions prepared in each example and comparative example, the following tests (1) and (2) were conducted. 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) and (2) passed.

[0070] (1) Outgas test of cured product: Each photocurable resin composition was irradiated with ultraviolet light having an integrated light amount of 40 kJ / m 2 to obtain a cured product. 20 mg of this cured product was weighed and set in a thermogravimetric analyzer TG / DTA220 manufactured by Seiko Instruments Inc., and the weight loss rate after 3 hours at 120 °C was measured and taken as the outgas amount. The results are summarized in Table 1. The outgas amount is preferably 2.0% by weight or less. (2) Phosphorus element elution test: Each photocurable resin composition was irradiated with ultraviolet light having an integrated light amount of 40 kJ / m 2 to obtain a cured product. 500 mg of this cured product was weighed and immersed in 300 ml of pure water at 95 °C for 100 hours to obtain an eluate. This eluate was set in an inductively coupled plasma mass spectrometer 7700x ICP-MS manufactured by Agilent Technologies, and the high-frequency output of the plasma: 1550 W, and the amount of phosphorus element after 0.1-second integration was measured. The results are summarized in Table 1. The amount of phosphorus element is preferably 0.1 ppm or less.

[0071]

Table 1

[0072] According to Examples 1 to 2 in Table 1, it can be seen that the present invention can provide a photocurable resin composition that is excellent in the low outgassing property of the cured product and from which phosphorus element does not elute. Comparative Example 1 in Table 1 is a composition in which the content of component (C) deviates from the predetermined content, but the outgassing property of the cured product is poor. Further, Comparative Examples 2 to 4 are compositions containing comparative components that are not component (A) or component (B) of the present invention, but the outgassing property of the cured product is poor. Further, Comparative Examples 5 to 16 are compositions containing comparative components that are not component (C) of the present invention, but the outgassing property of the cured product is poor or the phosphorus element elutes.

Industrial Applicability

[0073] The present invention has been made in view of the above circumstances, and since it is a photocurable resin composition that is excellent in the low outgassing property of the cured product and from which phosphorus element does not elute, 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.

Claims

1. A photocurable resin composition comprising the following components (A) to (C), wherein the component (C) is contained in an amount of 1 to 20 parts by mass based on 100 parts by mass of the component (A). Component (A): A polyisobutylene resin containing one or more (meth)acryloyl groups and a -[CH ２ C(CH ３ ) ２ -unit Component (B): isobornyl (meth)acrylate Component (C): a ketal-based photo radical polymerization initiator

2. The photocurable resin composition according to claim 1, wherein the component (C) is a benzyl ketal-based photo radical polymerization initiator.

3. The photocurable resin composition according to claim 1, wherein the component (C) is 2,2-dimethoxy-2-phenylacetophenone.

4. The photocurable resin composition according to claim 1, further comprising, as the component (D), a (meth)acrylate monomer having a linear or branched alkyl group with 5 to 30 carbon atoms (excluding the component (B)).

5. The photocurable resin composition according to claim 1, wherein the component (B) is contained in an amount of 30 to 130 parts by mass based on 100 parts by mass of the component (A).

6. The photocurable resin composition according to claim 1, which does not contain an acylphosphine-based photo radical polymerization initiator.

7. A sealant comprising the photocurable resin composition according to any one of claims 1 to 6.

8. A cured product obtained by irradiating the photocurable resin composition according to any one of claims 1 to 6 or the sealant according to claim 7 with light.

9. A fuel cell comprising any one of the seals consisting of the seal between adjacent separators in a fuel cell, the seal between the frame and the electrolyte membrane of the fuel cell, and the seal between the frame and the electrolyte membrane electrode assembly of the fuel cell, wherein any one of the seals is the cured product according to claim 8.

10. A method for sealing at least a part between at least two flanges of a component to be sealed having at least two flanges, the method comprising: applying the photocurable resin composition according to any one of claims 1 to 6 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; disposing the other flange on the gasket, and pressing the one flange coated with the photocurable resin composition and the other flange via the gasket to seal at least a part between the at least two flanges.

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