Photocurable resin composition for gaskets

Abstract

To provide a photocurable resin composition for a gasket which is excellent in shape maintenance, crushability and peelability.SOLUTION: A photocurable resin composition for a gasket contains a (meth)acrylate oligomer (A), a (meth)acrylate monomer (B), a thixotropic imparting agent (C), and a photopolymerization initiator (D), in which a content of the photopolymerization initiator (D) is 2.5 pts.wt. or more with respect to 100 pts.wt. of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B), a content of the methacrylate monomer is 30 pts.wt. or less with respect to 100 pts.wt. of the total of the (meth)acrylate monomer (B), and a rosin derivative is not contained, and a weight average molecular weight of the (meth)acrylate oligomer (A) is 1,500 or more or an elastic modulus of a cured product is 20 MPa or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photocurable resin composition for a gasket. [Background technology]

[0002] Photocurable resin compositions are used as sealing materials for electronic devices or precision parts. For example, in hard disk drives, a disk or its reading section is sealed by a gasket made of a photocurable resin composition to prevent contamination by moisture or dust. Regarding photocurable resin compositions used in such gaskets, Patent Documents 1 to 3 propose the use of rosin derivatives such as rosin esters in photocurable resin compositions for gaskets that contain (meth)acrylate oligomers, (meth)acrylate monomers, photopolymerization initiators, and thixotropic agents in order to reduce moisture permeability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-43642 A [Patent Document 2] JP 2017-8126 A [Patent Document 3] JP 2018-105421 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, photocurable resin compositions containing rosin derivatives as described in Patent Documents 1 to 3 have a problem in that they are difficult to peel from the interface between a member and the photocurable resin composition due to their increased adhesiveness.

[0005] Furthermore, it was found that there is room for improvement in terms of shape retention and crushability in the gasket agent. That is, when the shape retention of the gasket agent is poor, the shape of the applied gasket resin composition changes between the start and end of application, between application and the UV curing process, or during UV curing, which may cause the intended shape to be lost or the applied shape to be not uniform. Also, when the crushability of the gasket agent is poor, there is a tendency for problems to occur when the components are joined together, such as not being able to be tightened in the first place, the gasket not being crushed and not being able to adhere, or the components being deformed.

[0006] An object of the present invention is to provide a photocurable resin composition for gaskets that is excellent in shape retention, crushability and peelability. [Means for solving the problem]

[0007] The present invention includes the following. [1] A photocurable resin composition for gaskets, comprising: (A) a (meth)acrylate oligomer; (B) a (meth)acrylate monomer; (C) a thixotropic agent; and (D) a photopolymerization initiator, The weight average molecular weight of the (meth)acrylate oligomer (A) is 1,500 or more, The content of the photopolymerization initiator (D) is 2.5 parts by weight or more per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B); The content of the methacrylate monomer (B1) is 30 parts by weight or less based on 100 parts by weight of the total (meth)acrylate monomers (B), and Contains no rosin derivatives Photocurable resin composition for gaskets. [2] A photocurable resin composition for gaskets, comprising: (A) a (meth)acrylate oligomer; (B) a (meth)acrylate monomer; (C) a thixotropic agent; and (D) a photopolymerization initiator, The elastic modulus of the cured product of the photocurable resin composition for gaskets is 20 MPa or less, The content of the photopolymerization initiator (D) is 2.5 parts by weight or more per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B); The content of the methacrylate monomer (B1) is 30 parts by weight or less based on 100 parts by weight of the total (meth)acrylate monomers (B), and Contains no rosin derivatives Photocurable resin composition for gaskets. [3] The photocurable resin composition for gaskets [1] or [2], wherein the content of the (meth)acrylate oligomer (A) is 35 parts by weight or more and 80 parts by weight or less per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B). [4] A photocurable resin composition for gaskets according to any one of [1] to [3], comprising 50 parts by weight or more and 100 parts by weight or less of one or more selected from the group consisting of alkyl (meth)acrylates, hydroxyalkyl (meth)acrylates, cycloalkyl (meth)acrylates, aromatic (meth)acrylates, and tetrahydrofurfuryl alcohol (meth)acrylic acid polymer esters, relative to a total of 100 parts by weight of (meth)acrylate monomers (B). [5] A photocurable resin composition for gaskets according to any one of [1] to [4], in which the content of the thixotropic agent (C) is 0.01 parts by weight or more and 20 parts by weight or less per 100 parts by weight of the total of the photocurable resin composition for gaskets excluding the photopolymerization initiator (D) and the thixotropic agent (C). Effect of the Invention

[0008] According to the present invention, it is possible to provide a photocurable resin composition for gaskets that is excellent in shape retention, crushability and peelability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Definition] In this specification, "(meth)acrylic" means at least one of acrylic and methacrylic, and "(meth)acryloyl group" means at least one of acryloyl group and methacryloyl group. In this specification, the "weight average molecular weight" is a weight average molecular weight measured by gel permeation chromatography (GPC) and converted using a calibration curve of standard polystyrene. In this specification, when referring to a numerical range, the term "to" means that both ends of the range are included. That is, "35 to 80 parts by weight" means "35 parts by weight or more and 80 parts by weight or less." In this specification, "less than or equal to" means "the same as or less than," and "more than or equal to" means "the same as or greater than."

[0010] [Photocurable resin composition for gaskets] The photocurable resin composition for gaskets comprises a (meth)acrylate oligomer (A), a (meth)acrylate monomer (B), a thixotropic agent (C) and a photopolymerization initiator (D), wherein the weight average molecular weight of the (meth)acrylate oligomer (A) is 1,500 or more, the content of the photopolymerization initiator (D) is 2.5 parts by weight or more per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B), the content of the methacrylate monomer (B1) is 30 parts by weight or less per 100 parts by weight of the total of the (meth)acrylate monomer (B), and the photocurable resin composition does not contain a rosin derivative.

[0011] The photocurable resin composition for gaskets has excellent shape retention, crushability, and peelability, and therefore can be applied to a desired shape and location, and the shape does not change between the start and end of application, between application and the UV curing step, or until UV curing is completed, and the composition can fulfill the basic role of a gasket (airtightness and / or liquid tightness).

[0012] <(Meth)acrylate Oligomer (A)> The (meth)acrylate oligomer (A) is not particularly limited as long as it is an oligomer having one or more (meth)acryloyl groups in the molecule. Examples of the (meth)acrylate oligomer (A) include urethane (meth)acrylate oligomers and epoxy (meth)acrylate oligomers.

[0013] <<Urethane (meth)acrylate oligomer>> The urethane (meth)acrylate oligomer may be an aromatic, aliphatic, polyether, polycarbonate, polyester, or combination thereof. These may be used alone or in combination of two or more.

[0014] The urethane (meth)acrylate oligomer can be produced, for example, by reacting an organic diisocyanate with a resin having a hydroxyl group, and then further reacting the resulting resin with a mono- to penta-functional (meth)acrylate having a hydroxyl group, as described in JP 2008-260898 A.

[0015] Examples of the organic diisocyanate include aromatic, aliphatic, and alicyclic diisocyanates, and specific examples thereof include aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate, aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, and alicyclic diisocyanates such as hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane. Among these, alicyclic diisocyanates are preferred.

[0016] Examples of the resin having hydroxyl groups include polyalkylenes having hydroxyl groups at both ends, hydrogenated polyalkylenes having hydroxyl groups at both ends, polyols having hydroxyl groups at both ends, polycarbonates having hydroxyl groups at both ends, and polyesters having hydroxyl groups at both ends. Polyalkylenes having hydrogenated hydroxyl groups at both ends are preferred, and polybutadiene having hydrogenated hydroxyl groups at both ends and polyisoprene having hydrogenated hydroxyl groups at both ends are more preferred.

[0017] Examples of the mono- to penta-functional (meth)acrylate having a hydroxyl group include hydroxyalkylene (meth)acrylate, trimethylolpropane diacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and alkyl oxide modified products thereof.

[0018] In addition to those described in the examples, commercially available urethane (meth)acrylate oligomers include EBECRYL4858 (manufactured by Daicel-Allnex Corporation), UN-2301 (manufactured by Negami Chemical Industries, Ltd.), EBECRYL4859 (manufactured by Daicel-Allnex Corporation), and EBECRYL4738 (manufactured by Daicel-Allnex Corporation).

[0019] <<Epoxy (meth)acrylate oligomer>> The epoxy (meth)acrylate oligomer is an oligomer in which all epoxy groups in an epoxy resin are reacted with (meth)acrylic acid. The epoxy (meth)acrylate oligomer may include an oligomer in which some epoxy groups in an epoxy resin are reacted with (meth)acrylic acid, that is, an oligomer having an epoxy group and a (meth)acryloyl group in the resin. Here, examples of the epoxy resin include aromatic epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, and other epoxy resins. The epoxy (meth)acrylate oligomer is preferably an epoxy (meth)acrylate oligomer of an aromatic epoxy resin. The epoxy (meth)acrylate oligomer may be one type or a combination of two or more types.

[0020] Commercially available epoxy (meth)acrylate oligomers include EB3700 (manufactured by Daicel-Allnex) and EB3708 (manufactured by Daicel-Allnex).

[0021] <<Weight average molecular weight of (meth)acrylate oligomer (A)>> The weight average molecular weight of the (meth)acrylate oligomer (A) is 1,500 or more. When the weight average molecular weight of the (meth)acrylate oligomer (A) is less than 1,500, the elastic modulus of the cured product tends to be large and the crushability tends to be poor. The weight average molecular weight of the (meth)acrylate oligomer (A) is preferably 1,500 to 30,000. When the weight average molecular weight of the (meth)acrylate oligomer (A) is 30,000 or less, the tackiness of the cured product can be suppressed and the peelability tends to be better.

[0022] <<Preferred Embodiments of (Meth)acrylate Oligomer (A)>> The (meth)acrylate oligomer (A) preferably has 2-6 (meth)acryloyl groups, more preferably 2-4, and particularly preferably 2-3.

[0023] The (meth)acrylate oligomer (A) may be one or a combination of two or more. That is, the (meth)acrylate oligomer (A) may be one or more acrylate oligomers (A1), one or more methacrylate oligomers (A2), or a combination of one or more acrylate oligomers (A1) and one or more methacrylate oligomers (A2). The (meth)acrylate oligomer (A) is preferably an acrylate oligomer (A1), and more preferably a urethane acrylate oligomer.

[0024] <(Meth)acrylate Monomer (B)> The (meth)acrylate monomer (B) is not particularly limited as long as it is an acrylate monomer and / or a methacrylate monomer having one or more (meth)acryloyl groups in the molecule. Examples of the (meth)acrylate monomer (B) include alkyl (meth)acrylate monomers, (meth)acrylate monomers having a ring structure, (meth)acrylate monomers containing a hydroxyl group, (meth)acrylate monomers having a heterocyclic structure, and other (meth)acrylate monomers.

[0025] <<Alkyl (meth)acrylate monomer>> Examples of the alkyl (meth)acrylate monomer include methyl (meth)acrylate, ethyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, isomyristyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, isodecyl (meth)acrylate, stearyl (meth)acrylate, and lauryl (meth)acrylate.

[0026] <<(Meth)acrylate monomers having a ring structure>> The (meth)acrylate monomer having a ring structure is preferably at least one selected from the group consisting of aromatic (meth)acrylate monomers and alicyclic (meth)acrylate monomers. The (meth)acrylate monomer having a ring structure is not a (meth)acrylate monomer having a heterocyclic structure.

[0027] Examples of the aromatic (meth)acrylate monomer include benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, ethoxylated phenylphenol (meth)acrylate, phenoxybenzyl (meth)acrylate, naphthalene (meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, modified bisphenol A di(meth)acrylate (bisphenol A diglycidyl ether methacrylic acid adduct, bisphenol A alkylene oxide adduct diglycidyl ether methacrylic acid adduct, 9,9-bis[4-(2-methacryloyloxyethoxy)phenyl]fluorene), and the like.

[0028] Examples of the alicyclic (meth)acrylate monomer include dicyclopentenyloxyethyl (meth)acrylate, norbornene (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, and tert-butylcyclohexyl (meth)acrylate.

[0029] <<Hydroxyl group-containing (meth)acrylate monomer>> Examples of the hydroxyl group-containing (meth)acrylate monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, diethylene glycol monoethyl ether (meth)acrylate, polyol poly(meth)acrylate (containing hydroxyl group), etc. Here, examples of the polyol poly(meth)acrylate include trimethylolpropane di(meth)acrylate, polypentaerythritol poly(meth)acrylate, etc.

[0030] <<(Meth)acrylate monomers having heterocyclic structures>> Examples of the (meth)acrylate monomer having a heterocyclic structure include tetrahydrofurfuryl (meth)acrylate, ester of tetrahydrofurfuryl alcohol (meth)acrylic acid polymer, etc. Examples of commercially available products of ester of tetrahydrofurfuryl alcohol (meth)acrylic acid polymer include Viscoat #150D (manufactured by Osaka Organic Chemical Industry Co., Ltd.).

[0031] <<Other (meth)acrylate monomers>> Other (meth)acrylate monomers include (meth)acrylate monomers containing a carboxyl group, polyfunctional (meth)acrylate monomers, and the like.

[0032] <<<(Meth)acrylate monomers containing carboxyl groups>>> Examples of the (meth)acrylate monomer containing a carboxyl group include aliphatic, aromatic and alicyclic (meth)acrylate monomers containing a carboxyl group. Specific examples of (meth)acrylate monomers containing a carboxyl group include (meth)acrylic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxypropyl succinic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxypropyl phthalic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyloxypropyl hexahydrophthalic acid, and ω-carboxy-polycaprolactone mono(meth)acrylate.

[0033] <<<Polyfunctional (meth)acrylate monomer>>> Examples of the polyfunctional (meth)acrylate monomer include esters of aliphatic polyhydric alcohols and (meth)acrylic acid, and esters of alkylene oxide adducts of aliphatic polyhydric alcohols and (meth)acrylic acid. Specific examples of polyfunctional (meth)acrylate monomers include ethoxylated 1,6-hexanediol di(meth)acrylate, 1,6-hexanediol acrylic acid polymer ester, polyester di(meth)acrylate, polyethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, epichlorohydrin-modified glycerol tri(meth)acrylate, ethoxylated glycerol tri(meth)acrylate, PO (propylene oxide)-modified glycerol tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, alkoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol octa(meth)acrylate, and polypentaerythritol poly(meth)acrylate.

[0034] <<Preferred Embodiments of (Meth)acrylate Monomer (B)>> The weight average molecular weight of the (meth)acrylate monomer (B) is preferably less than 1500. The number of (meth)acryloyl groups contained in the (meth)acrylate monomer (B) is preferably 1-4, and particularly preferably 1-3.

[0035] The (meth)acrylate monomer (B) may be one or a combination of two or more kinds, i.e., the (meth)acrylate monomer (B) may be one or more kinds of methacrylate monomer (B1), one or more kinds of acrylate monomer (B2), or a combination of one or more kinds of methacrylate monomer (B1) and one or more kinds of acrylate monomer (B2).

[0036] <Thixotropic agent (C)> The thixotropic agent (C) may be an inorganic thixotropic agent or an organic thixotropic agent.

[0037] Examples of inorganic thixotropy-imparting agents include inorganic fine particles such as calcium carbonate, aluminum hydroxide, silica (fumed silica, precipitated silica), titanium oxide, asbestos powder, copper oxide, copper hydroxide, iron oxide, alumina, zinc oxide, lead oxide, magnesium oxide, tin oxide, carbon, mica, smectite, and carbon black. The inorganic thixotropy-imparting agents may be surface-treated. Examples of surface treatment agents for inorganic thixotropy-imparting agents include monoalkyltrialkoxysilane, dimethyldichlorosilane, polydimethylsiloxane, and hexamethyldisilazane. Surface-treated or untreated fumed silica may be commercially available.

[0038] Examples of organic thixotropy-imparting agents include organic fine particles such as polystyrene beads, polyethylene particles, acrylic particles, polysiloxane resin particles, isoprene rubber particles, and polyamide particles; polymeric compounds such as polyethylene, polysiloxane, polyacrylic, polyamide, polyvinyl alcohol, alkyl-modified cellulose, peptides, and polypeptides; and organic compounds such as amide wax, hydrogenated castor oil derivatives, 1,3,5-tris(trialkoxysilylalkyl)isocyanurate, fatty acid amides, oxidized polyethylene, sodium carboxymethylcellulose, xanthan gum, modified polyester polyol, ethyl cellulose, methyl cellulose, cellulose derivatives, and organic bentonite. The thixotropic agent (C) may be one type or a combination of two or more types.

[0039] <Photopolymerization initiator (D)> The photopolymerization initiator (D) may be a photoradical polymerization initiator that generates radicals by irradiation with light. Examples of the photoradical polymerization initiator include alkylphenones, benzophenones, acetophenones, acylphosphine oxides, titanocenes, oxime esters, benzoin ethers, thioxanthones, and anthraquinones.

[0040] Specific examples of photoradical polymerization initiators include 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, benzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1,2-hydroxy -2-Methyl-1-phenyl-propan-1-one, 2-methyl-1-[4-methylthio]phenyl]-2-morpholinopropan-1-one, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone], benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, oligo2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone , oligo 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanol, 2-hydroxy-2-methyl-1-phenyl-1-propanone, isopropylthioxanthone, o-benzoylbenzoic acid methyl ester, [4-(methylphenylthio)phenyl]phenylmethane, 2,4-diethylthioxanthone, 2-chlorothioxanthone, benzophenone, ethyl anthraquinone, benzophenone ammonium salt, thioxanthone ammonium salt, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentane phosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 4,4'-bisdiethylaminobenzophenone, 1,4 dibenzoylbenzene, 10-butyl-2-chloroacridone, 2,2'bis(o-chlorophenyl)4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)1,2'-biimidazole, 2,2'bis(o-chlorophenyl)4,5,4',5'-tetraphenyl-1,Examples of photoinitiators include 2'-biimidazole, 4-benzoyldiphenyl ether, acrylated benzophenone, bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, o-methylbenzoyl benzoate, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ethyl ester, active tertiary amines, carbazole-phenone photoinitiators, acridine photoinitiators, triazine photoinitiators, and benzoyl photoinitiators.

[0041] The photopolymerization initiator (D) may be a commercially available product. From the viewpoint of making the photopolymerization initiator (D) less susceptible to oxygen inhibition, which is a cause of non-curing in the radical reaction of the (meth)acrylate oligomer (A) and / or the (meth)acrylate monomer (B), oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are more preferable. The photopolymerization initiator (D) may be one type or a combination of two or more types.

[0042] <Other ingredients (E)> The photocurable resin composition for gaskets may contain other components such as a plasticizer (E1), an adhesion promoter, an antioxidant, an antifoaming agent, a colorant, a filler, a chain transfer agent, a heat and / or light stabilizer, a surface tension adjuster, a surfactant, a leveling agent, an ionic liquid, an ultraviolet absorber, a flame retardant, and a polymer, within the scope of the effects of the present invention. Here, when a liquid non-reactive compound such as a flame retardant, a polymer, an ionic liquid, etc. acts as a plasticizer, it is included in the plasticizer. In addition, when an antioxidant or an ultraviolet absorber acts as a heat and / or light stabilizer, it is included in the heat and / or light stabilizer. As these specific components, known components can be used. From the viewpoint of obtaining a cured product with a small elastic modulus and flexibility, the photocurable resin composition for gaskets may further contain a plasticizer (E1).

[0043] <<Plasticizer (E1)>> The plasticizer (E1) is a component that does not harden by itself upon irradiation with light. Examples of such plasticizers include plasticizers having an ester structure and plasticizers other than those having an ester structure. Examples of plasticizers having an ester structure include citrate ester plasticizers, phthalate ester plasticizers, polycarboxylic acid alkyl ester plasticizers, adipate ester plasticizers, sebacic acid ester plasticizers, and other ester plasticizers. Examples of plasticizers other than those having an ester structure include xylene resin-based plasticizers, acrylic polymer-based plasticizers, polybutadiene-based plasticizers, polyisoprene-based plasticizers, polybutene-based plasticizers, terpene-based plasticizers, and other plasticizers.

[0044] Examples of the citrate ester plasticizer include tributyl acetyl citrate, triethyl acetyl citrate, 2-ethylhexyl acetyl citrate, tributyl citrate, and triethyl citrate. Examples of the phthalate plasticizer include dibutyl phthalate, diisononyl phthalate, diheptyl phthalate, di(2-ethylhexyl) phthalate, diisodecyl phthalate, and butyl benzyl phthalate. Examples of polycarboxylic acid alkyl ester plasticizers include C3 to C12 alkyl esters of polycarboxylic acids such as diisononyl 1,2-cyclohexanedicarboxylate. Examples of the adipate plasticizer include adipate diesters such as dioctyl adipate, diisononyl adipate, diisodecyl adipate, and bis-(2-butoxyethyl) adipate. Examples of the sebacic acid ester plasticizer include dioctyl sebacate and diisononyl sebacate. Other ester-based plasticizers include phosphate esters such as tricresyl phosphate and tributyl phosphate; trimellitic esters such as trioctyl trimellitate; alkyl esters of polyoxyalkylene glycols such as triethylene glycol bis(2-ethylhexanoate) (for example, C3 to C12 alkyl esters of di-, tri-, or tetraethylene glycol); polyester-based plasticizers such as adipic acid polyesters and polyester polyols (excluding adipic acid diesters); epoxy-based ester-based plasticizers; and benzoic acid ester-based plasticizers.

[0045] The xylene resin plasticizer is an aromatic oligomer based on m-xylene, and examples of commercially available products include Nikanol LL and Nikanol L (manufactured by Fudow Co., Ltd.). The acrylic polymer plasticizer is a prepolymerized acrylic polymer (which may or may not contain a reactive group), and examples of commercially available products include UP1061 and UP1010 (manufactured by Toagosei Co., Ltd.). Examples of the polybutadiene-based plasticizer include polybutadiene, its hydrides, derivatives thereof having hydroxyl groups introduced at both ends, and derivatives of these hydrides having hydroxyl groups introduced at both ends. Examples of the polyisoprene-based plasticizer include polyisoprene, its hydrides, derivatives thereof having hydroxyl groups introduced at both ends, and derivatives of these hydrides having hydroxyl groups introduced at both ends. Examples of the polybutene plasticizer include polybutene, its hydrogenated derivatives, derivatives of these having hydroxyl groups introduced at both ends, and derivatives of these hydrogenated derivatives having hydroxyl groups introduced at both ends. Examples of the terpene plasticizer include terpene resins, terpene phenol resins, modified terpene resins, and hydrogenated terpene resins. Other plasticizers include polyol-based plasticizers such as polycarbonate polyol (excluding polyether polyol and polyester polyol); thermoplastic elastomers; petroleum resins; alicyclic saturated hydrocarbon resins; and polyether-based plasticizers such as polyether polyol.

[0046] Examples of adhesion promoters include silane coupling agents.Specific examples of adhesion promoters include trialkoxysilanes such as vinyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltriethoxysilane, ethoxytributoxysilane, cyclohexyltriethoxysilane, and phenyltriisopropoxysilane;tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, dimethoxydiethoxysilane, dimethoxydiisopropoxysilane, diethoxydiisopropoxysilane, and diethoxydibutoxysilane;dialkoxysilanes such as dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, diethyldibutoxysilane, and phenylethyldiethoxysilane.

[0047] Examples of the heat and / or light stabilizer include hindered phenol-based antioxidants, phosphorus-based processing heat stabilizers, sulfur-based heat stabilizers, hydroxylamine-based processing heat stabilizers, benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, hindered amine-based light stabilizers, and benzoate-based ultraviolet absorbers. Specific examples of heat and / or light stabilizers include dibutylhydroxytoluene (BHT), 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], n-butyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, octylated diphenylamine, 2,4,-bis[(octylthio)methyl]-O-cresol, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and dibutylhydroxytoluene.

[0048] Examples of the surface conditioner include silicone compounds such as polyether-modified silicone, polyester-modified silicone, polydimethylsiloxane, and polymethylalkylsiloxane; fluorine compounds such as fluoroalkyl carboxylic acid and perfluoroalkyl carboxylic acid; silicone-fluorine compounds such as perfluoro-modified silicone; and acrylic compounds such as poly(meth)acrylate, polyether-modified acrylic polymer, polyester-modified acrylic polymer, and perfluoroalkyl-modified acrylic polymer. Examples of commercially available surface conditioners include polyether-modified siloxane (TEGOGLIDE440, Evonik).

[0049] Examples of the filler include inorganic fillers and organic fillers, and include not only powder fillers but also fillers that may act as conductive agents, static neutralizers, flame retardants, buffer improvers, colorants, etc. Examples of the inorganic fillers include metal oxides and metal hydroxide particles such as silica, fumed silica, precipitated silica, asbestos powder, copper oxide, copper hydroxide, iron oxide, alumina, aluminum hydroxide, zinc oxide, lead oxide, magnesia, and tin oxide, as well as inorganic fine particles such as calcium carbonate, carbon, silica, mica, talc, smectite, and carbon black, expanded graphite powder, powdered graphite, or metal fine particles. Examples of the organic fillers include organic fine particles such as polyethyl acrylate resin, polyurethane resin, polyethylene resin, polypropylene resin, urea resin, melamine resin, benzoguanamine resin, phenol resin, acrylic resin, styrene resin, and silicone resin. Fillers which also act as flame retardants include powdered organic halogen compounds, red phosphorus, antimony trioxide, expandable graphite, magnetite, or aluminum hydroxide.

[0050] Examples of colorants include various pigments and dyes, and these additives can be appropriately selected depending on the application.

[0051] The other components (E) may each be one type or a combination of two or more types, for example, one or more plasticizers (E1) may be combined with one or more components other than the plasticizer. The photocurable resin composition for gaskets does not contain a rosin derivative. When the photocurable resin composition for gaskets contains a rosin derivative, the peelability is poor. The rosin derivative is a substance derived from rosin obtained from pine resin or the like, and examples of the rosin derivative include rosin ester, hydrogenated rosin ester, acid-modified rosin, rosin-containing diol, metal salt of rosin, disproportionated rosin, rosin-modified phenolic resin, maleic rosin, and maleic acid-modified rosin resin. Other examples of the rosin derivative include those described in JP 2017-43642 A, JP 2017-8126 A, and JP 2018-105421 A.

[0052] <Content> The content of each component in the photocurable resin composition for gaskets is as follows. The content of the methacrylate monomer (B1) is 30 parts by weight or less per 100 parts by weight of the (meth)acrylate monomer (B). If the content of the methacrylate monomer (B1) exceeds 30 parts by weight per 100 parts by weight of the (meth)acrylate monomer (B), the peelability is poor. The content of the methacrylate monomer (B1) is preferably 20 parts by weight or less per 100 parts by weight of the (meth)acrylate monomer (B). The remainder is the acrylate monomer (B2).

[0053] The content of the photopolymerization initiator (D) is 2.5 parts by weight or more per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B). If the content of the photopolymerization initiator (D) is less than 2.5 parts by weight per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B), the peelability is poor. It is preferable that the content of the photopolymerization initiator (D) is 20 parts by weight or less per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B).

[0054] The content of each component in the photocurable resin composition for gaskets is preferably as follows. The content of the (meth)acrylate oligomer (A) is preferably 35 parts by weight or more and 80 parts by weight or less, more preferably 40 parts by weight or more and 80 parts by weight or less, and particularly preferably 50 parts by weight or more and 80 parts by weight or less, relative to 100 parts by weight in total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B). When the content of the (meth)acrylate oligomer (A) is within the above range, the effects of the present invention can be efficiently exhibited.

[0055] The total content of the alkyl (meth)acrylate, hydroxyalkyl (meth)acrylate, cycloalkyl (meth)acrylate, aromatic (meth)acrylate and tetrahydrofurfuryl alcohol (meth)acrylic acid polymer ester is preferably 50 parts by weight or more and 100 parts by weight or less relative to 100 parts by weight of the (meth)acrylate monomer (B). If it is within such a range, the effect of the present invention can be exhibited more efficiently.

[0056] The content of the thixotropic agent (C) is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 20 parts by weight, and particularly preferably 1 to 15 parts by weight, based on 100 parts by weight of the total photocurable resin composition for gaskets excluding the photopolymerization initiator (D) and the thixotropic agent (C). When the content of the thixotropic agent (C) is within the above range, both the ejection property and the liquid shape retention can be achieved.

[0057] The content of the plasticizer (E1) is preferably 100 parts by weight or less, more preferably 80 parts by weight or less, and particularly preferably 70 parts by weight or less, based on 100 parts by weight in total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B). When the content of the plasticizer (E1) is 100 parts by weight or less, based on 100 parts by weight in total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B), softening is possible without inhibiting surface curability.

[0058] The content of the filler is preferably 100 parts by weight or less, more preferably 70 parts by weight or less, and particularly preferably 40 parts by weight or less, per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B). When the content of the filler is 100 parts by weight or less, per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B), it is possible to improve the releasability while maintaining the viscosity and elastic modulus in the optimum range.

[0059] The total content of the (meth)acrylate oligomer (A), the (meth)acrylate monomer (B), the plasticizer (E1) and the filler is preferably 50 parts by weight or more and 100 parts by weight or less, and particularly preferably 70 parts by weight or more and 100 parts by weight or less, based on 100 parts by weight of the photocurable resin composition for gaskets excluding the photopolymerization initiator (D) and the thixotropic agent (C). If it is in such a range, the effect of the present invention can be efficiently exhibited. Note that, when the photocurable resin composition for gaskets does not contain the plasticizer (E1) and / or the filler, the above total is the total content of the (meth)acrylate oligomer (A), the (meth)acrylate monomer (B), and the filler and / or the plasticizer (E1).

[0060] <Viscosity, thixotropy ratio> Shear rate of photocurable resin composition for gaskets: 1 sec -1 From the viewpoint of shape retention, the viscosity at shear rate of the photocurable resin composition for gaskets is preferably 1,000 to 1,000,000 mPa·s, and particularly preferably 10,000 to 500,000 mPa·s. -1 The viscosity at may be 60,000 to 1,000,000 mPa·s, 80,000 to 1,000,000 mPa·s, or 100,000 to 1,000,000 mPa·s. Shear rate of photocurable resin composition for gaskets: 10 sec -1From the viewpoint of ejection property, the viscosity at a shear rate of 10 to 100,000 mPa·s is preferably 1,000 to 80,000 mPa·s. -1 The viscosity at may be 15,000 to 100,000 mPa·s, or 20,000 to 100,000 mPa·s. The thixotropic ratio (TI value) of the photocurable resin composition for gaskets is preferably 1.2-10, more preferably 1.5-10, and particularly preferably 3.3-10, from the viewpoints of dischargeability and shape retention. The viscosity of the photocurable resin composition for gaskets was measured using a rheometer (manufactured by Anton Paar) with a cone rotor (φ=25 mm, rotor angle 2°) at 25° C. at a shear rate of 0.01 (s -1 ) to 100(sec -1 The thixotropy ratio is the value measured by changing the shear rate to 1 s -1 Viscosity at 10 sec / shear rate -1 Viscosity at a shear rate of 1 s -1 "Viscosity at shear rate of 10 seconds" -1 The viscosity at 100° C. is calculated by dividing the viscosity at 100° C. by the viscosity at 100° C.

[0061] <Elasticity modulus> From the viewpoint of sealing property and crushing property, the elastic modulus of the cured product of the photocurable resin composition for gaskets is preferably 20 MPa or less, more preferably 0.01 to 20 MPa, further preferably 0.1 to 10 MPa, and particularly preferably 0.2 to 5 MPa. The specific conditions for curing the photocurable resin composition for gaskets when obtaining the cured product are arbitrary, but are preferably 365 nm LED and 400 mW / cm 2 The curing condition may be set to 30 seconds.

[0062] A specific method for measuring the elastic modulus may be as follows. The photocurable resin composition for gaskets is cured under the above conditions to obtain a dumbbell-shaped test piece with a measurement part of 30 mm in length, 5 mm in width, and 0.5 mm in thickness. A tensile test is performed on the obtained test piece at 25°C at a speed of 10 mm / min using a Minebea Technograph TG-2kN tension and compression tester, and the elastic modulus of the cured product is calculated.

[0063] [Further photocurable resin composition for gaskets] Further, the photocurable resin composition for gaskets comprises a (meth)acrylate oligomer (A'), a (meth)acrylate monomer (B), a thixotropic agent (C) and a photopolymerization initiator (D), and the cured product has an elastic modulus of 20 MPa or less, the content of the photopolymerization initiator (D) is 2.5 parts by weight or more per 100 parts by weight of the total of the (meth)acrylate oligomer (A') and the (meth)acrylate monomer, and the content of the methacrylate monomer is 30 parts by weight or less per 100 parts by weight of the total of the (meth)acrylate monomer, and does not contain a rosin derivative.

[0064] In the further photocurable resin composition for gaskets, the (meth)acrylate oligomer (A') is as described for the (meth)acrylate oligomer (A) except that the weight average molecular weight thereof may be 1,500 or less. In the further photocurable resin composition for gaskets, the (meth)acrylate monomer (B), the thixotropic agent (C), the photopolymerization initiator (D), and the contents and properties of each component are as described in the photocurable resin composition for gaskets. The elastic modulus of the cured product in the further photocurable resin composition for gaskets is preferably 0.01 to 20 MPa, particularly preferably 0.1 to 10 MPa, from the viewpoint of sealing property and crushing property. The specific conditions for curing the photocurable resin composition for gaskets when obtaining the cured product are as described in the photocurable resin composition for gaskets. The elastic modulus of the cured product can be increased by decreasing the molecular weight of the (meth)acrylate oligomer (A') or increasing the content of the (meth)acrylate oligomer (A'). In addition, the elastic modulus of the cured product can be increased by adding a filler or increasing the amount of the filler. The elastic modulus of the cured product can be decreased by adding a plasticizer or increasing the amount of the plasticizer.

[0065] (Method of preparation and use) The photocurable resin composition for gaskets can be produced by mixing the respective components, and can be used by a known method. EXAMPLES

[0066] The compositions of the examples and comparative examples were produced using the following raw materials. The "molecular weight" refers to the weight average molecular weight. The "number of functional groups" in the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B) refers to the number of (meth)acryloyl groups in the molecule.

[0067] 1. (Meth)acrylate Oligomer (A) UV3520EA (polyester urethane acrylate (diluted with 30% ethyl acetate), manufactured by Mitsubishi Chemical Corporation. Functional group number: 2. Molecular weight: 14,000.) The UV3520EA solvent-removed product was obtained by removing ethyl acetate from UV3520EA. UV3300B (Polyether urethane acrylate, manufactured by Mitsubishi Chemical Corporation. Functional groups: 2. Molecular weight: 13,000.) EBECRYL 210 (aromatic urethane acrylate, manufactured by Daicel-Allnex Corporation. Functional groups: 2. Molecular weight: 1,500.) UN9200A (Polycarbonate urethane acrylate, manufactured by Negami Chemical Industries, Ltd. Functional group number: 2. Molecular weight: 15,000.) UV3200B (polyester urethane acrylate, manufactured by Mitsubishi Chemical Corporation. Functional groups: 2. Molecular weight: 10,000.) UV3000B (polyester urethane acrylate, manufactured by Mitsubishi Chemical Corporation. Functional groups: 2. Molecular weight: 18,000.) EBECRYL 8402 (Aliphatic urethane acrylate, manufactured by Daicel-Allnex Corporation. Number of functional groups: 2. Molecular weight: 1,000.)

[0068] 2. (Meth)acrylate Monomer (B) 2-1. Methacrylate monomer (B1) BZ (benzyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd., number of functional groups: 1) HOB (2-hydroxybutyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd., functional group number: 1) HO-MS (2-methacryloyloxyethyl succinate, manufactured by Kyoeisha Chemical Co., Ltd., number of functional groups: 1) 2-2. Acrylate monomer (B2) LA (Lauryl acrylate, manufactured by Kyoeisha Chemical Co., Ltd., Number of functional groups: 1) A-BZ (benzyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd., number of functional groups: 1) 4-HBA (4-hydroxybutyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., functional group number: 1) IBOA (Isobornyl acrylate, manufactured by Nippon Shokubai Co., Ltd., functional group number: 1) Viscoat #150D (tetrahydrofurfuryl alcohol acrylic acid polymer ester, manufactured by Osaka Organic Chemical Industry Co., Ltd., number of functional groups: 1)

[0069] 3. Thixotropic agent (C) VP NKC130 (Octyltrimethoxysilane-treated fumed silica, manufactured by Nippon Aerosil Co., Ltd.) CAB-O-SIL TG-308F (fumed silica, manufactured by Cabot Corporation) 4. Photopolymerization initiator (D) KIP150 (oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], manufactured by Lamberti) Omnirad 819 (Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, manufactured by IGM Resins BV) 5. Other Ingredients (E) Plasticizer (E1) CTROFLEX A-4 (acetyl tributyl citrate, manufactured by Morimura Shoji Co., Ltd.) PB-3A (benzoic acid ester, manufactured by DIC) Filler (E) HE-3040 (high density polyethylene, manufactured by Sumitomo Seika Chemicals) SG-95 (talc, manufactured by Nippon Talc Co., Ltd.) 6. Rosin derivatives KE-311 (hydrogenated rosin ester (solid), manufactured by Arakawa Chemical Industries, Ltd.)

[0070] The compositions of Examples 1 to 16 and Comparative Examples 1 to 5 were prepared by mixing the ingredients in the amounts (parts by weight) shown in Tables 1 to 3 below and stirring with a stirrer (RW28 (IKA), 600 rpm).

[0071] 〔evaluation〕 (1) Viscosity The viscosity was measured using a rheometer (manufactured by Anton Paar) with a cone rotor (φ=25 mm, rotor angle 2°) at 25°C and a shear rate of 0.01 (s -1 ) to 100(sec -1 ) and the measurements were performed.

[0072] (2) TI value (thixotropic index) The TI value was calculated according to the following formula: TI value = shear rate 1 (sec -1 ) Viscosity / shear rate 10(sec -1 ) Viscosity at

[0073] (3) Elastic modulus (MPa) Uses 365nm LED, 400mW / cm 2 The composition was cured under the conditions of 30 x 30 seconds to obtain a dumbbell-shaped test piece with a measurement area of ​​30 mm in length, 5 mm in width, and 0.5 mm in thickness. A tensile test was carried out at 25°C and a speed of 10 mm / min using a Minebea Technograph TG-2kN tension and compression tester to measure the elastic modulus.

[0074] (4) Coating shape (shape retention) Using a dispenser (Musashi Engineering), the solution was applied in a square shape onto a 5cm x 5cm x 3mm SUS (with screw holes at each corner). The shape of the solution was observed with a laser microscope (Olympus) 1 minute and 5 minutes after application. ◎: The change in resin height after 1 minute and after 5 minutes is within 5% ○: The change in resin height between 1 minute and 5 minutes is more than 5% and less than 10% ×: The change in resin height between 1 minute and 5 minutes is more than 10%

[0075] (5) Crushability Apply in the same manner as above and cure with UV (using 365 nm LED, 400 mW / cm 2 The sample was then compressed by 20% and 30% of the applied height after being placed in a 5cm x 5cm x 3mm PC (polycarbonate, with screw holes in the four corners) and screwed in place. A thickness gauge equivalent to the spacer was used to check whether the sample could be compressed to the specified thickness, and the crushability was evaluated. ◎: The specified thickness is reached uniformly throughout at both 20% and 30% compression. ○: The entire surface uniformly reaches the specified thickness at 20% compression, and there are some areas that do not reach the specified thickness at 30% compression. ×: Some parts do not collapse to the specified thickness even with 20% compression

[0076] (6) Waterproof test (liquid-tightness) The coating was applied in the same manner as above, UV cured, water-sensitive paper was attached to the inside of the coating area, and a spacer was installed so that it was compressed by 20% of the coating height. After sandwiching it with SUS, screws were fastened, and it was submerged 30 cm in water to evaluate the liquid-tightness. ○: No discoloration on water-sensitive paper after 30 minutes. ×: Discoloration of the water-sensitive paper occurs after 30 minutes.

[0077] (7) Peelability The workpiece after the above SUS bonding was peeled off, and the peelability was evaluated according to the following criteria. ◯: Easily peeled off from the interface, no adhesive residue ×: Not easily peeled off from the interface, or cohesive failure occurred, or liquid components were attached

[0078] The above results are summarized in Tables 1 to 3.

[0079] [Table 1]

[0080] [Table 2]

[0081] [Table 3]

[0082] The compositions of the examples were excellent in shape retention, crushability and peelability. Furthermore, the compositions of the examples were excellent in liquid-tightness and could be used as gaskets. Comparison of Example 1 with Examples 2 and 3, and comparison of Example 4 with Example 5, showed that when the composition further contained a plasticizer, the elastic modulus of the cured product was smaller. Comparing Examples 1 to 5, 7, and 9 to 12 with Examples 6 and 8, it was found that when the elastic modulus of the cured product was low, the crushability was superior. By comparing Examples 1, 3-4, 7, and 8 with Examples 2, 3, 6, and 9-16,-1 When the viscosity at the coating temperature was high and the TI value was large, the coating shape was better. Comparison of Examples 3, 9, and 10 and Comparative Example 4 shows that even when the composition contains a methacrylate monomer, the effect of the present invention is achieved when the content of the (meth)acrylate monomer (B1) is 30 parts by weight or less per 100 parts by weight of the total of the (meth)acrylate monomers (B). A comparison between Example 16 and Example 3 shows that the effects of the present invention were achieved even when the type of plasticizer was changed.

[0083] The composition of Comparative Example 1 did not contain a thixotropic agent, and therefore had low thixotropy and poor shape retention. The composition of Comparative Example 2, which contained a rosin derivative, had poor releasability. The composition of Comparative Example 3 had poor crushability because the weight average molecular weight of the (meth)acrylate oligomer (A) was less than 1,500, or the elastic modulus of the cured product exceeded 20 MPa. The composition of Comparative Example 4 had poor releasability because the content of the methacrylate monomer (B1) exceeded 30 parts by weight per 100 parts by weight of the total of the (meth)acrylate monomers (B). The composition of Comparative Example 5 had poor releasability because the content of the photopolymerization initiator (D) was less than 2.5 parts by weight per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B).

Claims

1. A photocurable resin composition for gaskets, comprising: a (meth)acrylate oligomer (A), a (meth)acrylate monomer (B), a thixotropic agent (C), a photopolymerization initiator (D), and a plasticizer (E1), The weight average molecular weight of the (meth)acrylate oligomer (A) is 1,500 or more, The content of the photopolymerization initiator (D) is 2.5 parts by weight or more based on 100 parts by weight in total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B); the content of the methacrylate monomer (B1) is 30 parts by weight or less based on 100 parts by weight of the total of the (meth)acrylate monomers (B); the plasticizer (E1) is at least one selected from the group consisting of citrate ester plasticizers, adipate ester plasticizers, sebacate ester plasticizers, and benzoate ester plasticizers; Does not contain rosin derivatives, and The elastic modulus of the cured product of the photocurable resin composition for gaskets is 2.2 MPa or less. Photocurable resin compositions for gaskets (however, excluding photocurable resin compositions for gaskets containing a vinyl monomer having a propylene glycol skeleton, excluding photocurable resin compositions for gaskets containing acryloyl-terminated polyisobutylene, and excluding photocurable resin compositions for gaskets containing a phosphate ester having a photoreactive functional group in the molecule).

2. 2. The photocurable resin composition for gaskets according to claim 1, wherein the content of the (meth)acrylate oligomer (A) is 35 parts by weight or more and 80 parts by weight or less per 100 parts by weight of the total of the (meth)acrylate oligomer (A) and the (meth)acrylate monomer (B).

3. 3. The photocurable resin composition for gaskets according to claim 1 or 2, comprising 50 parts by weight or more and 100 parts by weight or less of one or more selected from the group consisting of alkyl (meth)acrylates, hydroxyalkyl (meth)acrylates, cycloalkyl (meth)acrylates, aromatic (meth)acrylates, and tetrahydrofurfuryl alcohol (meth)acrylic acid polymer esters, relative to a total of 100 parts by weight of the (meth)acrylate monomers (B).

4. The photocurable resin composition for gaskets according to any one of claims 1 to 3, wherein the content of the thixotropic agent (C) is 0.01 parts by weight or more and 20 parts by weight or less based on a total of 100 parts by weight of the photocurable resin composition for gaskets excluding the photopolymerization initiator (D) and the thixotropic agent (C).

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