Photocurable resin composition

Abstract

The present invention provides a photocurable resin composition that can be cured with visible light, can be used as an adhesive or a sealant for members that include polyethylene naphthalate (PEN) and do not readily transmit ultraviolet light, and also has excellent acidic aqueous solution resistance. This photocurable resin composition includes (A) an oligomer that has at least one (meth)acryloyl group, (B) a thioxanthone photoinitiator, and (C) a tertiary amine that has at least two aromatic rings in the molecule thereof.

Description

Photocurable resin composition

[0001] The present invention relates to a photocurable resin composition.

[0002] In recent years, fuel cells have been attracting attention as a new energy system for automobiles and homes. A fuel cell is a power generation device that generates electricity by chemically reacting hydrogen and oxygen. Furthermore, fuel cells are a clean, next-generation power generation device due to their high energy efficiency and the production of water through the reaction of hydrogen and oxygen. Fuel cells are classified into four types: polymer electrolyte fuel cells (PEFCs), phosphoric acid fuel cells (PFCs), molten carbonate fuel cells (MCFCs), and solid oxide fuel cells (SOFCs). Among these, polymer electrolyte fuel cells offer high power generation efficiency despite their relatively low operating temperatures (around 80°C), making them promising for use in automobile power sources, home power generators, small power sources for electronic devices such as mobile phones, and emergency power sources. Subgaskets made of PEN (polyethylene naphthalate) are used to seal fuel cells and electrolytes, which consist of oxidizers and an acidic aqueous solution, to prevent leakage (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 2018-160447

[0004] Since the PEN used in the subgasket blocks light in the ultraviolet region (365 nm wavelength region), the adhesives and sealants used in the subgasket must be curable in the visible light region. However, conventional photocurable resin compositions that are curable in visible light are not resistant to acidic aqueous solutions.

[0005] As a result of extensive research to achieve the above object, the present inventors have completed a photocurable resin composition that cures well in the visible light region (405 nm wavelength region) and has excellent resistance to acidic aqueous solutions.

[0006] The gist of the present invention will now be described.

[0007] [1] A photocurable resin composition comprising components (A) to (C): component (A): an oligomer having one or more (meth)acryloyl groups in one molecule; component (B): a thioxanthone-based photoinitiator; and component (C): a tertiary amine having two or more aromatic rings in one molecule.

[0008] [2] The photocurable resin composition according to [1], wherein the component (A) is a polyisobutylene resin having one or more (meth)acryloyl groups.

[0009] [3] The photocurable resin composition according to [1] or [2], wherein the content of the component (B) is 0.05 to 10 parts by mass per 100 parts by mass of the component (A).

[0010] [4] The photocurable resin composition according to [1] or [2], wherein the content of the component (C) is 0.05 to 10 parts by mass per 100 parts by mass of the component (A).

[0011] [5] The photocurable resin composition according to [1] or [2], wherein the component (C) is a compound having an α-aminoalkylphenone structure.

[0012] [6] The photocurable resin composition according to [1] or [2], further comprising, as component (D), a compound having one or more (meth)acryloyl groups in one molecule (excluding component (A)).

[0013] [7] The photocurable resin composition according to [6], wherein the component (D) contains either a monofunctional aliphatic (meth)acrylate or a monofunctional alicyclic (meth)acrylate.

[0014] [8] The photocurable resin composition according to [1] or [2], which is used on an adherend containing polyethylene naphthalate.

[0015] [9] A sealant for a fuel cell comprising the photocurable resin composition according to [1] or [2].

[0016]

[10] A cured product obtained by curing the photocurable resin composition according to [1] or [2] with active energy rays having a wavelength of 400 to 780 nm.

[0017] The present invention provides a photocurable resin composition that is curable with visible light, can be applied to polyethylene naphthalate (PEN) and other materials that are difficult to transmit ultraviolet light, and has excellent resistance to acidic aqueous solutions.

[0018] The present invention will be described in detail below. However, the present invention is not limited to the following embodiments. In this specification, "X to Y" means a range including the numerical values ​​(X and Y) written before and after it as the lower and upper limits, respectively, and means "X or more and Y or less." In the present invention, a compound having a (meth)acryloyl group refers to a (meth)acrylate. The (meth)acryloyl group may have the (meth)acryloyl group in the form of a (meth)acryloyloxy group. Furthermore, the term "(meth)acryloyl" includes both acryloyl and methacryloyl. Therefore, for example, the term "(meth)acryloyl group" refers to an acryloyl group (H ２ C=CH-C(=O)-) and methacryloyl groups (H ２ C=C(CH ３ )-C(=O)-). Similarly, the term "(meth)acrylate" includes both acrylate and methacrylate, the term "(meth)acrylic" includes both acrylic and methacrylic, and the term "(meth)acrylamide" includes both acrylamide and methacrylamide. In this specification, "mass" is synonymous with "weight."

[0019] The component (A) of the present invention is an oligomer having one or more (meth)acryloyl groups per molecule. The (meth)acryloyl groups may be bonded to the terminal or side chain of the oligomer, but are preferably bonded to the terminal from the viewpoint of excellent curability of the photocurable resin composition. The "oligomer" referred to in the present invention refers to a polymer in which two to several tens of monomer units (including monomer units other than (meth)acrylate monomers) are repeated, and which has a weight-average molecular weight of 1,000 or more.

[0020] The main chain structure of component (A) is not particularly limited, but examples thereof include a polyether main chain structure, a polyester main chain structure, a polycarbonate main chain structure, a polyurethane main chain structure, a polyamide main chain structure, a polyurea main chain structure, a polyimide main chain structure, and a vinyl polymer main chain structure. Among these, a vinyl polymer main chain structure is preferred due to its excellent rubber properties and high degree of freedom in polymer design. Component (A) may also be a mixture containing two or more main chain structures. The vinyl polymer main chain structure is not particularly limited as long as it is a vinyl polymer structure obtained by polymerizing a compound having an ethylenically unsaturated group. Specific examples include polyethylene, polypropylene, polyisobutylene, poly(meth)acrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride, polybutadiene, polyisoprene, polyvinyl acetate, polyvinyl butyral, and polyvinyl ether. Among these, a polyisobutylene resin having one or more (meth)acryloyl groups is preferred, as it can provide a cured product with excellent gas barrier properties and excellent resistance to acidic aqueous solutions.

[0021] The polyisobutylene resin having one or more (meth)acryloyl groups includes, for example, —[CH ２ C(CH ３ ) ２ ]- units (polyisobutylene skeleton), and ２ C(CH ３ ) ２ The component (A) may be a polyisobutylene resin containing other structural units than the —[CH ]- unit. ２ C(CH ３ ) ２ ]- units, for example, in an amount of 70% by mass or more, preferably 75% by mass or more, and more preferably 80% by mass or more, based on the total amount of structural units. ２ C(CH ３ ) ２ ]-units in an amount of, for example, 100% by mass or less, in another embodiment, 95% by mass or less, and in still another embodiment, 90% by mass or less. The component (A) preferably has 1 to 6, more preferably 2 to 4, even more preferably 2 to 3, and particularly preferably 2 (meth)acryloyl groups.

[0022] Specific examples of the polyisobutylene resin having one or more (meth)acryloyl groups include polyisobutylene polymers having (meth)acryloyloxyalkoxyphenyl groups. The main skeleton of component (A) in the present invention is a polyisobutylene skeleton. While isobutylene is primarily used as the monomer constituting this polyisobutylene skeleton, other monomers may be copolymerized within a range that does not impair the effects of the present invention. Component (A) is preferably liquid at room temperature (25°C) for excellent workability. Component (A) is characterized by low moisture permeability due to the inclusion of a polyisobutylene skeleton. Component (A) may be a diblock or triblock compound with other blocks, but a monoblock compound is most preferred. Component (A) contains two or more (meth)acryloyloxy groups in the compound, and preferably has two (meth)acryloyloxy groups from the viewpoint of curability.

[0023] The method for producing the component (A) is not limited, and the component can be produced by the methods described in JP 2013-35901 A, WO 2013 / 047314 A, WO 2017 / 099043 A, etc.

[0024] Specific examples of the component (A) include EP400V in the EPION (registered trademark) series manufactured by Kaneka Corporation, but are not limited thereto.

[0025] The component (A) may contain one type alone or two or more types in combination.

[0026] Component (B) of the present invention is a thioxanthone-based photoinitiator. Use of component (B) can impart visible light curability, and use of component (B) in combination with component (A) and component (C), described below, can improve resistance to acidic aqueous solutions. Specific examples of component (B) include, but are not limited to, thioxanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-dimethylthioxanthene-9-one, 2,4-diethylthioxanthone, 1-chloro-4-propoxythioxanthone, and 2,4-diethylthioxanthene-9-one, among other thioxanthone derivatives. From the viewpoint of visible light curability and acid aqueous solution resistance when used in combination with the components (A) and (C), thioxanthone, 2,4-dimethylthioxanthene-9-one, and 2,4-diethylthioxanthene-9-one are preferred, 2,4-dimethylthioxanthene-9-one and 2,4-diethylthioxanthene-9-one are more preferred, and 2,4-diethylthioxanthene-9-one is most preferred. The component (B) may contain one type alone or two or more types in combination.

[0027] The content of the component (B) is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and most preferably 0.3 to 3 parts by mass, per 100 parts by mass of the component (A). By having the content of the component (B) be 0.05 to 10 parts by mass per 100 parts by mass of the component (A), it is possible to impart visible light curability to the photocurable resin composition and improve the acidic aqueous solution resistance of the cured product.

[0028] The component (C) of the present invention is a tertiary amine having two or more aromatic rings in one molecule. By using the component (C) in combination with the component (B), the visible light curability of the photocurable resin composition and the acidic aqueous solution resistance of the cured product can be improved. From the viewpoint of acidic aqueous solution resistance, the component (C) preferably has two to four aromatic rings in one molecule, and most preferably has two. From the viewpoint of improving visible light curability and acidic aqueous solution resistance by using the component (B) in combination, the component (C) is preferably a compound having an α-aminoalkylphenone structure, and more preferably has a molecular weight of 300 to 500. Specific examples include 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone and 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one, but from the viewpoint of obtaining a cured product with even better resistance to acidic aqueous solutions, 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one is preferred. The component (C) may contain one type alone or two or more types in combination.

[0029] The content of the component (C) is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and most preferably 0.3 to 3 parts by mass, per 100 parts by mass of the component (A). By having the content of the component (C) be 0.05 to 10 parts by mass per 100 parts by mass of the component (A), it is possible to impart visible light curability to the photocurable resin composition and improve the acidic aqueous solution resistance of the cured product.

[0030] The mass ratio of the component (B) to the component (C) (mass of the component (B):mass of the component (C)) is preferably 90:10 to 10:90, more preferably 70:30 to 30:70, and most preferably 40:60 to 60:40. By having this ratio of 90:10 to 10:90, it is possible to impart visible light curability to the photocurable resin composition, and further improve the acidic aqueous solution resistance of the cured product.

[0031] Furthermore, the photocurable resin composition of the present invention preferably contains, as component (D), a compound having one or more (meth)acryloyl groups in one molecule (excluding component (A)). By including component (D), workability and adhesive strength can be improved. From the viewpoint of improving workability when mixed with component (A), a (meth)acrylate monomer is preferred. Examples of (meth)acrylate monomers include monofunctional (meth)acrylate monomers, bifunctional (meth)acrylate monomers, trifunctional (meth)acrylate monomers, and (meth)acrylamide monomers. Two or more types of (meth)acrylate monomers may be used in combination. Furthermore, multiple other (meth)acrylate monomers may also be used in combination. The molecular weight of these (meth)acrylate monomers is not particularly limited, but is, for example, less than 1,000. From the viewpoint of improving workability, the component (D) is preferably a monofunctional (meth)acrylate monomer or a bifunctional (meth)acrylate monomer, more preferably a monofunctional (meth)acrylate monomer, and particularly preferably a monofunctional acrylate monomer.

[0032] Specific examples of the monofunctional (meth)acrylate monomer include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, butoxyethyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octylheptyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate. aliphatic (meth)acrylates such as methyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, ethoxypolypropylene glycol (meth)acrylate, and mono(2-(meth)acryloyloxyethyl)succinate; alicyclic (meth)acrylates such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, mono(2-(meth)acryloyloxyethyl)tetrahydrophthalate, and mono(2-(meth)acryloyloxyethyl)hexahydrophthalate;Benzyl (meth)acrylate, phenyl (meth)acrylate, o-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, p-cumylphenoxyethyl (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, 1-naphthoxyethyl (meth)acrylate, 2-naphthoxyethyl (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxy aromatic (meth)acrylates such as phenoxy polyethylene glycol (meth)acrylate, phenoxy polypropylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-(o-phenylphenoxy)propyl (meth)acrylate, 2-hydroxy-3-(1-naphthoxy)propyl (meth)acrylate, and 2-hydroxy-3-(2-naphthoxy)propyl (meth)acrylate; 2-tetrahydrofurfuryl (meth)acrylate heterocyclic (meth)acrylates such as acrylate, N-(meth)acryloyloxyethylhexahydrophthalimide, 2-(meth)acryloyloxyethyl-N-carbazole, caprolactone-modified products thereof, ω-carboxy-polycaprolactone mono(meth)acrylate, glycidyl (meth)acrylate, α-ethylglycidyl (meth)acrylate, α-propylglycidyl (meth)acrylate, α-butylglycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 2-ethyl ... compounds having an ethylenically unsaturated group and an epoxy group, such as butylglycidyl (meth)acrylate, 2-propylglycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 3,4-epoxyheptyl (meth)acrylate, α-ethyl-6,7-epoxyheptyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinylbenzyl glycidyl ether;Ethylenically unsaturated groups and oxetanyl such as (2-ethyl-2-oxetanyl)methyl (meth)acrylate, (2-methyl-2-oxetanyl)methyl (meth)acrylate, 2-(2-ethyl-2-oxetanyl)ethyl (meth)acrylate, 2-(2-methyl-2-oxetanyl)ethyl (meth)acrylate, 3-(2-ethyl-2-oxetanyl)propyl (meth)acrylate, and 3-(2-methyl-2-oxetanyl)propyl (meth)acrylate compounds having an ethylenically unsaturated group and an isocyanate group, such as 2-(meth)acryloxyethyl isocyanate; compounds having an ethylenically unsaturated group and a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate;

[0033] From the viewpoint of not lowering the acid aqueous solution resistance, the (D) component preferably contains either one of a monofunctional aliphatic (meth)acrylate or a monofunctional alicyclic (meth)acrylate, more preferably contains one or more compounds selected from the group consisting of lauryl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate, and most preferably contains both lauryl (meth)acrylate and isobornyl (meth)acrylate. Also, from the viewpoint of more excellent reactivity, the (D) component preferably contains either one of a monofunctional aliphatic acrylate or a monofunctional alicyclic acrylate, and preferred specific examples are as described above.

[0034] Specific examples of the bifunctional (meth)acrylate monomer include 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and ethylene oxide-modified neopentyl glycol di(meth). ) acrylate, propylene oxide side-modified neopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, epichlorohydrin-modified bisphenol A di(meth)acrylate, ethylene oxide-modified bisphenol S di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, dicyclopentenyl di(meth)acrylate, ethylene oxide-modified dicyclopentenyl di(meth)acrylate, di(meth)acryloyl isocyanurate, and the like, but are not limited to these.

[0035] The content of the (D) component is preferably 1 to 200 parts by weight, more preferably 30 to 150 parts by weight, and most preferably 50 to 100 parts by weight, per 100 parts by weight of the (A) component. A content of 1 to 200 parts by weight of the (D) component per 100 parts by weight of the (A) component improves workability and prevents a decrease in acidic aqueous solution resistance. When the (D) component contains both a monofunctional alicyclic (meth)acrylate and a monofunctional aliphatic (meth)acrylate, the mass ratio of the alicyclic (meth)acrylate to the aliphatic (meth)acrylate is preferably 40:60 to 95:5, more preferably 50:50 to 95:5. A ratio of 40:60 to 95:5 prevents a decrease in adhesion to PEN or acidic aqueous solution resistance.

[0036] The photocurable resin composition of the present invention may contain an antifoaming agent, a rheology control agent, an antioxidant, etc. in an appropriate amount within the range that does not impair the properties. The addition of these can improve workability and heat resistance.

[0037] Examples of the defoaming agent include silica-based compounds, amide-based compounds, silicone-based (including polysiloxane-based) compounds, and paraffin-based mineral oils, but in the present invention, silicone-based (including polysiloxane-based) compounds are preferred in terms of their defoaming effect. From the viewpoints of improving the defoaming properties of the photocurable resin composition of the present invention and not reducing the visible light curability or acidic aqueous solution resistance, the content of the defoaming agent is preferably 0.1 to 5 mass%, and more preferably 0.5 to 3 mass%, relative to 100 mass% of the entire photocurable resin composition.

[0038] The rheology control agent generally refers to an additive that controls the rheological properties of a composition when added to the composition, and is called a thixotropic agent, anti-settling agent, anti-sagging agent, thickener, etc. Examples of the rheology control agent include inorganic rheology control agents such as amorphous silicon dioxide, montmorillonite, bentonite, and colloidal alumina; polyolefin rheology control agents such as polyethylene and polypropylene; cellulose rheology control agents such as nitrocellulose, carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose; alginic acid rheology control agents such as sodium alginate; protein rheology control agents such as casein, sodium caseinate, and ammonium caseinate; polyvinyl alcohol and polyvinylpyrrolidone; Examples of suitable rheology control agents include urea-based rheology control agents; polyacrylic acid-based rheology control agents such as sodium polyacrylate; polyether-based rheology control agents such as polyether dialkyl esters and polyether dialkyl ethers; urea-based rheology control agents obtained by reacting an isocyanate group-containing compound such as methyl isocyanate, ethyl isocyanate, ethylene diisocyanate, or hexamethylene diisocyanate with an amino group-containing compound such as ethylamine, propylamine, ethylene diamine, or hexamethylene diamine; and polycarboxylic acid-based rheology control agents such as polyhydroxycarboxylic acid amides. Among these, polycarboxylic acid-based rheology control agents are preferred from the viewpoint of not reducing the visible light curability or acidic aqueous solution resistance, and rheology control agents containing polyhydroxycarboxylic acid amides are more preferred. From the viewpoints of improving the workability of the photocurable resin composition of the present invention and not reducing the visible light curability or acidic aqueous solution resistance, the content of the rheology control agent is preferably 0.01 to 5 mass%, more preferably 0.05 to 3 mass%, relative to 100 mass% of the total photocurable resin composition.

[0039] Examples of the antioxidant that can be used include phenolic antioxidants, hindered phenolic antioxidants, organic sulfur antioxidants, amine antioxidants, and benzotriazole antioxidants. Among these, from the viewpoint of not reducing the visible light curability and acidic aqueous solution resistance, phenolic antioxidants are preferred, and dibutylhydroxytoluene (BHT) is more preferred. From the viewpoint of improving the heat resistance of the photocurable resin composition of the present invention and not reducing the visible light curability and acidic aqueous solution resistance, the content of the antioxidant is preferably 0.001 to 3 mass%, more preferably 0.01 to 2 mass%, relative to 100 mass% of the entire photocurable resin composition.

[0040] The photocurable resin composition of the present invention can be produced by a conventionally known method. For example, it can be produced by blending predetermined amounts of components (A), (B), and (C), and optionally added component (D) and other components, and mixing them using a mixing means such as a mixer (e.g., a planetary mixer) at a temperature of preferably 10 to 70°C for preferably 0.1 to 5 hours. It is also preferable to produce the composition in a light-shielded environment.

[0041] <Coating Method> The photocurable resin composition of the present invention can be applied to an adherend by a known coating method for resin compositions, such as dispensing using an automatic coater, spraying, inkjet printing, screen printing, gravure printing, dipping, spin coating, or the like.

[0042] <Curing Method> The photocurable resin composition of the present invention can be cured by irradiation with active energy rays such as ultraviolet rays and visible light. In particular, the photocurable resin composition of the present invention has excellent visible light curing properties, and therefore can be suitably used for curing with active energy rays of 400 nm to 780 nm, which are visible light rays. The source of the active energy rays used in this case is not particularly limited, and examples include 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, and electron beam irradiation devices. The dose (cumulative light amount) of active energy ray irradiation is set to 10 kJ / m from the viewpoint of the properties of the cured product. ２ It is preferable that the concentration is equal to or higher than 20 kJ / m ２ From the viewpoint of the tact time of the curing process, ２ It is preferably 60 kJ / m or less, and more preferably 60 kJ / m ２ or less, and particularly preferably 50 kJ / m ２ The following is the result.

[0043] <Adherend> The photocurable resin composition of the present invention can be used with an adherend that is not particularly limited, but examples thereof include metal-metal, metal and plastic, metal and rubber, metal and glass, plastic and rubber, plastic and glass, plastic-plastic, rubber-rubber, rubber-glass, and glass-glass. Examples of metals include, but are not limited to, gold, silver, iron, aluminum, magnesium, copper, stainless steel, and titanium. Examples of plastics include, but are not limited to, fiber-reinforced plastic (FRP), carbon fiber-reinforced plastic (CFRP), polyacrylic, polyester, polyamide, acrylonitrile-butadiene-styrene, nylon 6, polycarbonate, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyphenylene ether, polyether ether ketone, polyethylene, polypropylene, and polyethylene naphthalate. Examples of rubbers include, but are not limited to, nitrile rubber, butyl rubber, urethane rubber, silicone rubber, and EPDM. In particular, the photocurable resin composition of the present invention has excellent adhesive strength to polyethylene naphthalate (PEN), and is therefore suitable for use with adherends containing polyethylene naphthalate (PEN).

[0044] <Applications> From the viewpoint of the low moisture permeability derived from component (A) and the visible light curability and acidic aqueous solution resistance obtained from the combination with components (B) to (C), the photocurable resin composition of the present invention can be used in fuel cells, solar cells, dye-sensitized solar cells, lithium ion batteries, electrolytic capacitors, liquid crystal displays, organic EL displays, electronic paper, LEDs, hard disk drives, photodiodes, optical communications / circuits, electric wires / cables / optical fibers, optical isolators, laminates such as IC cards, sensors, substrates, pharmaceutical / medical instruments / devices, etc. Among these, the photocurable resin composition of the present invention is particularly preferably used for fuel cells because of its excellent acidic aqueous solution resistance.

[0045] <Sealing Method> The photocurable resin composition of the present invention is preferably used as a sealant. A sealant is applied to the gaps of one adherend or two or more adherends to keep the interior airtight, thereby preventing leakage and preventing the intrusion of moisture from the outside, so-called sealing. Hereinafter, a composition containing the photocurable resin composition for this purpose before curing will be referred to as a sealant, a cured product obtained by curing the photocurable resin composition for use as a sealant will be referred to as a seal, and the curing method will be referred to as a sealing method.

[0046] When the photocurable resin composition of the present invention is used as a sealant, it is preferably liquid at 25° C., and more preferably has a viscosity of 1 to 100 Pa·s at 25° C. Sealing methods using the photocurable resin composition of the present invention are not particularly limited, but examples include FIPG (formed-in-place gasket), CIPG (cured-in-place gasket), and MIPG (molded-in-place gasket).

[0047] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0048] Example 1, Comparative Examples 1 to 8 The following components were prepared to prepare photocurable resin compositions. Component (A): Polyisobutylene having a (meth)acryloyl group (number of (meth)acryloyl functional groups: 2, trade name: EPION EP400V (manufactured by Kaneka Corporation)) Component (B): 2,4-diethylthioxanthen-9-one (trade name: JRCure-1106 (manufactured by Tianjin Kunikushi New Materials Co., Ltd.)) Component (B'-1): 3-ketocoumarin (trade name: Esacure 3644 (manufactured by IGM Resins)) Component (B'-2): Benzophenone (reagent) Component (B'-3): 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO (manufactured by IGM Resins)) Component (B'-4): 2-hydroxy-2-methyl-1-phenylpropanone (trade name: Omnirad 1173 (manufactured by IGM Resins)) (C) component: 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one (molecular weight: 380.53, trade name: JRCure-1118 (manufactured by Tianjin Kunikushi New Materials Co., Ltd.)) (C') component: ethyl-4-(dimethylamino)benzoate (molecular weight: 193.25, trade name: Omnirad EDB (manufactured by IGM Resins)) (D-1) isobornyl acrylate (trade name: Light Acrylate IB-XA (manufactured by Kyoeisha Chemical Co., Ltd.)) (D-2) lauryl acrylate (trade name: Light Acrylate L-A (manufactured by Kyoeisha Chemical Co., Ltd.)) (D-3) dicyclopentanyl methacrylate (trade name: Fancryl FA-513M (manufactured by Resonac Corporation)) (Others) Silicone-based defoaming agent (a mixture of hydrophobic particles and defoaming polysiloxane, product name: BYK-1799 (manufactured by BYK Japan Co., Ltd.)) Rheology control agent (a solution of polyhydroxycarboxylic acid amide, product name: RHEOBYK-405 (manufactured by BYK Japan Co., Ltd.)) Antioxidant (dibutylhydroxytoluene, BHT) (reagent)

[0049] Resin compositions of Example 1 and Comparative Examples 1 to 8 were prepared. Components other than components (B) and (C) were weighed into a stirring vessel and stirred with a mixer for 30 minutes. Next, components (B) and (C) were added in the dark, and the mixture was stirred with a mixer for 30 minutes. Detailed amounts prepared are shown in Table 1, and all values ​​are expressed in parts by mass.

[0050]

[0051] A visible light curing test and an acid aqueous solution resistance test were carried out on the resin compositions of Example 1 and Comparative Examples 1 to 8. The results are summarized in Table 2.

[0052] [Visible light curing] The photocurable resin compositions of Example 1 and Comparative Examples 1 to 8 were applied to a PEN test piece measuring 10 mm in width, 30 mm in length, and 200 μm in thickness. After that, a similar PEN test piece was attached and fixed to the test piece so as to have a width of 10 mm and a length of 5 mm. Then, the test piece was subjected to a visible light irradiation at a wavelength of 405 nm and an integrated light amount of 45 kJ / m ２ The photocurable resin composition was cured by irradiating it with light of 1000 W at 1000 W to prepare a test piece. The test piece was evaluated according to the following evaluation criteria. A rating of "A" was deemed to be acceptable. <Evaluation criteria> A: The two bonded test pieces did not come apart when stress was applied by hand (cured). B: The two bonded test pieces came apart when stress was applied by hand (not cured).

[0053] [Acid aqueous solution resistance] Using a tensile tester, both ends of the test piece prepared in the visible light curing test were fixed and pulled at a pulling rate of 10 mm / min. The strength at the maximum load (shear adhesive strength) was measured according to JIS K6850 (1999) and recorded as the initial measured value. The adhesive area was 10 mm x 5 mm (unit: MPa). A sulfuric acid aqueous solution of pH 3.0 was placed in a glass bottle, the test piece was immersed, the glass bottle was sealed, and the bottle was left standing in a constant temperature bath at 95 ° C for 500 hours. The glass bottle was removed from the constant temperature bath and returned to room temperature, after which the test piece was washed with water and dried at room temperature for 2 hours. Using a tensile tester, both ends of the dried test piece were fixed and pulled at a pulling rate of 10 mm / min. The measured strength at the maximum load (shear adhesive strength) was recorded as the measured value after 95 ° C x 500 h (unit: MPa). In addition, since no curing was confirmed in the visible light curing test for Comparative Examples 6 to 8, they were excluded from the evaluation of acid aqueous solution resistance. (Percentage of change) The percent of change was calculated using the following formula. Tests with a percent of change within ±20% were considered to be acceptable. Percentage of change (%) = (shear adhesive strength after immersion at 95°C for 500 hours - initial shear adhesive strength) / initial shear adhesive strength x 100 (%)

[0054]

[0055] The photocurable resin composition of Example 1, which contained components (A) to (C), also exhibited good visible light curability, and showed little decrease in adhesive strength even after an acidic aqueous solution test. Comparative Examples 6 and 7, which used 2-hydroxy-2-methyl-1-phenylpropanone instead of component (B), lacked visible light curability and did not cure. Comparative Examples 1, 2, 4, and 5, which used 3-ketocoumarin, benzophenone, or 2,4,6-trimethylbenzoyl-diphenylphosphine oxide instead of component (B), exhibited good visible light curability, but showed a significant decrease in adhesive strength in the acidic aqueous solution test. Comparative Example 3, which used a tertiary amine (ethyl-4-(dimethylamino)benzoate) having only one aromatic ring per molecule instead of component (C), also showed a significant decrease in adhesive strength in the acidic aqueous solution test. Comparative Example 8, which used benzophenone instead of component (B) and did not contain component (C), did not exhibit visible light curability. These findings demonstrate that combining components (A) to (C) can achieve both visible light curability and acidic aqueous solution resistance.

[0056] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2024-058439) filed on April 1, 2024, the contents of which are incorporated herein by reference.

[0057] The photocurable resin composition of the present invention is curable with visible light, is applicable to substrates such as polyethylene naphthalate (PEN) that are poorly transparent to ultraviolet light, exhibits excellent adhesive strength, and is resistant to acidic aqueous solutions, making it extremely useful industrially.

Claims

1. A photocurable resin composition comprising components (A) to (C): Component (A): an oligomer having one or more (meth)acryloyl groups in one molecule; Component (B): a thioxanthone-based photoinitiator; and Component (C): a tertiary amine having two or more aromatic rings in one molecule.

2. The photocurable resin composition according to claim 1, wherein component (A) is a polyisobutylene resin having one or more (meth)acryloyl groups.

3. The photocurable resin composition according to claim 1 or 2, wherein the content of the component (B) is 0.05 to 10 parts by mass per 100 parts by mass of the component (A).

4. A photocurable resin composition according to claim 1 or 2, wherein the content of said component (C) is 0.05 to 10 parts by mass per 100 parts by mass of said component (A).

5. The photocurable resin composition according to claim 1 or 2, wherein the component (C) is a compound having an α-aminoalkylphenone structure.

6. The photocurable resin composition according to claim 1 or 2, further comprising, as component (D), a compound having one or more (meth)acryloyl groups in one molecule (excluding component (A)).

7. The photocurable resin composition according to claim 6, wherein component (D) contains either a monofunctional aliphatic (meth)acrylate or a monofunctional alicyclic (meth)acrylate.

8. The photocurable resin composition according to claim 1 or 2, which is used on an adherend containing polyethylene naphthalate.

9. A sealant for fuel cells comprising the photocurable resin composition according to claim 1 or 2.

10. A cured product obtained by curing the photocurable resin composition according to claim 1 or 2 with active energy rays having a wavelength of 400 to 780 nm.

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