Polymerizable composition, photocurable adhesive, method for producing cured product, and cured product

Abstract

To provide a polymerizable composition which has low viscosity and gives a cured product excellent in moist heat resistance and adhesive force.SOLUTION: The polymerizable composition contains a cationically polymerizable compound (A) and a photocationic polymerization initiator (B). The cationically polymerizable compound (A) contains an epoxy polymer (A1) and a monofunctional epoxy compound (A2). The cationically polymerizable compound (A) preferably contains an aliphatic epoxy compound (A3), preferably contains an oxetane compound (A4), and preferably contains an alicyclic epoxy compound (A6).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polymerizable composition containing a cationically polymerizable compound. [Background technology]

[0002] Cationically polymerizable compositions are used in the fields of inks, paints, various coating agents, adhesives, optical members, and the like. For example, the following Patent Documents 1 to 3 disclose various photocurable adhesives. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-236389 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-149262 [Patent Document 3] International Publication No. 2008 / 111584 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a polymerizable composition which has a low viscosity and gives a cured product having excellent resistance to moist heat and adhesive strength. [Means for solving the problem]

[0005] As a result of extensive investigations, the present inventors have found that a polymerizable composition that gives a cured product having excellent moist heat resistance and adhesive strength can be obtained by using an epoxy polymer and a monofunctional epoxy compound in combination as a cationically polymerizable compound, and have arrived at the present invention.

[0006] The present invention is a polymerizable composition containing a cationically polymerizable compound (A) and a photocationic polymerization initiator (B), wherein the cationically polymerizable compound (A) contains an epoxy polymer (A1) and a monofunctional epoxy compound (A2). [Effects of the Invention]

[0007] The polymerizable composition of the present invention has a low viscosity and the cured product has excellent resistance to moist heat and adhesive strength, and is therefore particularly useful as an adhesive. DETAILED DESCRIPTION OF THE INVENTION

[0008] The polymerizable composition of the present invention will be described below. The polymerizable composition of the present invention contains an epoxy polymer (A1) and a monofunctional epoxy compound (A2) as the cationically polymerizable compound (A).

[0009] The epoxy polymer (A1) is preferably a polyfunctional epoxy compound having a specific novolac structure, and examples thereof include phenol novolac epoxy resins, cresol novolac epoxy resins, phenol-naphthol novolac epoxy resins, bisphenol novolac epoxy resins, and aralkyl epoxy resins in which an aralkyl group is introduced into the main chain of a novolac structure.

[0010] In the present invention, a polymerizable composition in which the epoxy polymer (A1) has a structural unit represented by the following general formula (I) is preferred because it gives a cured product with excellent moist heat resistance and adhesive strength.

[0011] [ka] In the formula, Ar represents a benzene ring or a naphthalene ring. R 1represents a halogen atom, a hydroxyl group, a nitro group, a cyano group, a hydrocarbon group of 1 to 20 carbon atoms which may have a substituent, a heterocyclic group of 2 to 10 carbon atoms which may have a substituent, a heterocyclic group containing 3 to 30 carbon atoms which may have a substituent, or a group in which one or more methylene groups in the hydrocarbon group of 1 to 20 carbon atoms have been substituted with a divalent group selected from the following <Group A>, or a group in which one or more methylene groups in the heterocyclic group containing 3 to 30 carbon atoms have been substituted with a divalent group selected from the following <Group A>, Y 1 , Y 2 and Y 3 each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, or a group in which one or more methylene groups in the hydrocarbon group having 1 to 20 carbon atoms have been substituted with a divalent group selected from the following <Group A>, a represents an integer of 0 to 4, b represents an integer of 0 to 4; c represents an integer of 0 to 4; a+b is 1 to 4, and a+b+c is 1 to 4. <Group A>: -O-, -CO-, -COO-, -OCO-, -NR 11 -, -NR 12 CO-, -S- R 11 and R 12 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.

[0012] Examples of the halogen atom in the general formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0013] The hydrocarbon group having 1 to 20 carbon atoms in the general formula (I) is a group consisting of carbon atoms and hydrogen atoms and having 1 to 20 carbon atoms. Examples of the hydrocarbon group having 1 to 20 carbon atoms include aliphatic hydrocarbon groups having 1 to 20 carbon atoms and aromatic hydrocarbon ring-containing groups having 6 to 20 carbon atoms.

[0014] Examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms in the general formula (I) include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, and a cycloalkylalkyl group having 4 to 20 carbon atoms.

[0015] The alkyl group having 1 to 20 carbon atoms may be linear or branched. Examples of linear alkyl groups include methyl, ethyl, propyl, butyl, iso-amyl, tert-amyl, hexyl, heptyl, and octyl. Examples of branched alkyl groups include iso-propyl, sec-butyl, tert-butyl, iso-butyl, iso-pentyl, tert-pentyl, 2-hexyl, 3-hexyl, 2-heptyl, 3-heptyl, iso-heptyl, tert-heptyl, iso-octyl, tert-octyl, 2-ethylhexyl, nonyl, isononyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, hebrotadecyl, and octadecyl.

[0016] Examples of cycloalkyl groups having 3 to 20 carbon atoms include saturated monocyclic alkyl groups having 3 to 20 carbon atoms, saturated polycyclic alkyl groups having 3 to 20 carbon atoms, and groups having 4 to 20 carbon atoms in which one or more hydrogen atoms in the ring of these groups have been substituted with an alkyl group. Examples of the saturated monocyclic alkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl. Examples of the saturated polycyclic alkyl groups include adamantyl, decahydronaphthyl, octahydropentalene, and bicyclo[1.1.1]pentanyl. Examples of alkyl groups substituting hydrogen atoms in the ring of saturated monocyclic or saturated polycyclic alkyl groups include the groups exemplified above as alkyl groups having 1 to 20 carbon atoms. Examples of groups in which one or more hydrogen atoms in the ring of a saturated polycyclic alkyl group have been substituted with an alkyl group include bornyl.

[0017] A cycloalkylalkyl group having 4 to 20 carbon atoms means a group having 4 to 20 carbon atoms in which a hydrogen atom of an alkyl group is substituted with a cycloalkyl group. The cycloalkyl group in the cycloalkylalkyl group may be monocyclic or polycyclic. Examples of cycloalkylalkyl groups having 4 to 20 carbon atoms and a monocyclic cycloalkyl group include cyclopropylmethyl, 2-cyclobutylethyl, 3-cyclopentylpropyl, 4-cyclohexylbutyl, cycloheptylmethyl, cyclooctylmethyl, 2-cyclononylethyl, and 2-cyclodecylethyl. Examples of cycloalkylalkyl groups having 4 to 20 carbon atoms and a polycyclic cycloalkyl group include 3-3-adamantylpropyl and decahydronaphthylpropyl.

[0018] The aromatic hydrocarbon ring-containing group having 6 to 20 carbon atoms in the general formula (I) is a hydrocarbon group that contains an aromatic hydrocarbon ring but does not contain a heterocycle, and may have an aliphatic hydrocarbon group. Examples of the aromatic hydrocarbon ring-containing group include an aryl group having 6 to 20 carbon atoms and an arylalkyl group having 7 to 20 carbon atoms.

[0019] The aryl group having 6 to 20 carbon atoms may have a monocyclic structure, a fused ring structure, or two linked aromatic hydrocarbon rings. Examples of the aryl group having a fused ring structure having 6 to 20 carbon atoms include hydrocarbon-type aromatic fused ring groups having 7 to 20 carbon atoms, which are structures in which two or more aromatic hydrocarbon rings are fused together.

[0020] Examples of the aryl group having a monocyclic structure and having 6 to 20 carbon atoms include phenyl, tolyl, xylyl, ethylphenyl, 2,4,6-trimethylphenyl, etc. Examples of the hydrocarbon-type aromatic fused ring group having 7 to 20 carbon atoms include naphthyl, anthracenyl, phenanthryl, pyrenyl, fluorenyl, and indenofluorenyl.

[0021] The aryl group in which two aromatic hydrocarbon rings are linked may be one in which two aromatic hydrocarbon rings of a monocyclic structure are linked together, one in which an aromatic hydrocarbon ring of a monocyclic structure and an aromatic hydrocarbon ring of a fused ring structure are linked together, or one in which an aromatic hydrocarbon ring of a fused ring structure and an aromatic hydrocarbon ring of a fused ring structure are linked together. Examples of the linking group that links two aromatic hydrocarbon rings include a single bond, a sulfide group (—S—), and a carbonyl group. Examples of the aryl group in which two monocyclic aromatic hydrocarbon rings are linked together include biphenyl, diphenyl sulfide, and benzoylphenyl.

[0022] An arylalkyl group having 7 to 20 carbon atoms is a group in which one or more hydrogen atoms in an alkyl group are substituted with an aryl group. Examples of the arylalkyl group having 7 to 20 carbon atoms include benzyl, fluorenyl, indenyl, 9-fluorenylmethyl, α-methylbenzyl, α,α-dimethylbenzyl, phenylethyl, and naphthylpropyl groups.

[0023] As a substituent that the hydrocarbon group having 1 to 20 carbon atoms may have, a group having a reactive group capable of forming a carbon-carbon covalent bond by reacting with itself is preferred, as this improves curability. Examples of the reactive group include epoxy groups such as a glycidyl ether group and a cycloalkene oxide group; ethylenically unsaturated groups such as an acrylic group, a methacrylic group, a vinyl group, and a vinyl ether group; a halogen atom, a cyano group, a nitro group, a hydroxyl group, an amino group, a carboxyl group, a mercapto group, and an isocyanate group. Among the reactive groups, a glycidyl ether group and a cycloalkene oxide group are preferred because of their good adhesiveness, and a glycidyl ether group is particularly preferred because of their good heat resistance. The portion of the group having a reactive group other than the reactive group is a hydrocarbon group having 1 to 15 carbon atoms or a hydrocarbon group having 1 to 15 carbon atoms in which one or more methylene groups have been substituted with a divalent group selected from the above <Group A>, and examples of the hydrocarbon group having 1 to 15 carbon atoms include those having 1 to 15 carbon atoms selected from the above examples of the hydrocarbon group having 1 to 20 carbon atoms.

[0024] Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms include groups in which one hydrogen atom has been removed from the aforementioned hydrocarbon group having 1 to 20 carbon atoms, such as alkylene groups and arylene groups, and these groups may have the same substituent as the aforementioned hydrocarbon group having 1 to 20 carbon atoms.

[0025] The heterocyclic group having 2 to 10 carbon atoms in the general formula (I) is a group in which one hydrogen atom has been removed from a heterocyclic compound. The heterocyclic group may have a monocyclic structure or a fused ring structure. Examples of the heterocyclic group having a fused ring structure having 2 to 10 carbon atoms include a heterocycle-containing fused ring group having 3 to 10 carbon atoms, which is a structure in which a heterocycle and a heterocycle or a hydrocarbon ring are fused together. Specific examples of heterocyclic groups include pyridyl, quinolyl, thiazolyl, tetrahydrofuranyl, dioxolanyl, tetrahydropyranyl, methylthiophenyl, hexylthiophenyl, benzothiophenyl, pyrrolyl, pyrrolidinyl, imidazolyl, imidazolidinyl, imidazolinyl, pyrazolyl, pyrazolidinyl, piperidinyl, piperazinyl, pyrimidinyl, furyl, thienyl, benzoxazol-2-yl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl, morpholinyl, and the like. The heterocyclic group may have a substituent, and examples of the substituent include a halogen atom, a cyano group, a nitro group, a hydroxyl group, a thiol group, -COOH, or -SO2H.

[0026] The heterocyclic ring-containing group having 3 to 30 carbon atoms in the general formula (I) is a group having 3 to 30 carbon atoms in which one or more hydrogen atoms in a hydrocarbon group have been substituted with a heterocyclic group. Examples of the heterocyclic group include the groups exemplified above as the heterocyclic group having 2 to 10 carbon atoms. Examples of the hydrocarbon group include the hydrocarbon group having 1 to 20 carbon atoms. The heterocycle-containing group may have an aromatic hydrocarbon ring-containing group or an aliphatic hydrocarbon group, and may have a substituent such as a halogen atom, a cyano group, a nitro group, a hydroxyl group, a thiol group, -COOH, or -SOH. Furthermore, the "number of carbon atoms of 3 to 30" in the heterocyclic ring-containing group having 3 to 30 carbon atoms refers to the total number of carbon atoms in the heterocyclic ring-containing group.

[0027] The hydrocarbon group having 1 to 20 carbon atoms and the heterocyclic ring-containing group having 3 to 30 carbon atoms in which two or more methylene groups have been substituted with a divalent group selected from the above <Group A> do not have a structure in which the divalent groups are adjacent to each other.

[0028] In the present invention, when a hydrogen atom in the group is substituted with a substituent, the number of carbon atoms in the group refers to the number of carbon atoms in the group after the substitution. For example, when a hydrogen atom in the alkyl group having 1 to 20 carbon atoms is substituted, the number of carbon atoms of 1 to 20 refers to the number of carbon atoms after the hydrogen atom is substituted, not the number of carbon atoms before the hydrogen atom is substituted. In the present invention, the number of carbon atoms in a group in which a methylene group in a group with a predetermined number of carbon atoms is replaced with a divalent group defines the number of carbon atoms in the group before the substitution. For example, in the case of a group in which a methylene group in an alkyl group having 1 to 20 carbon atoms is replaced with a divalent group, the term "1 to 20 carbon atoms" refers to the number of carbon atoms before the methylene group in the alkyl group is replaced with the divalent group, not the number of carbon atoms after the replacement.

[0029] In the general formula (I), Y 1 However, a group in which one hydrogen atom has been removed from an aromatic hydrocarbon ring-containing group having 6 to 20 carbon atoms is preferred, and among these, a polymerizable composition in which the arylene group having 6 to 20 carbon atoms, which may have a substituent, is preferred because it can give a cured product having excellent moist heat resistance and adhesive strength. Examples of the arylene group include a phenylene group, a biphenylene group, and a naphthylene group. A phenylene group is preferred because it can give a polymerizable composition with low viscosity and excellent handleability, and a biphenylene group is preferred because it can give a polymerizable composition with particularly good adhesiveness and a cured product having excellent heat resistance and moist heat resistance.

[0030] In the general formula (I), Y 2 and Y 3 However, an aliphatic hydrocarbon group having 1 to 20 carbon atoms is preferred, and among these, an alkylene group having 1 to 20 carbon atoms is preferred, and an alkylene group having 1 to 10 carbon atoms is particularly preferred, and among these, an alkylene group having 1 to 5 carbon atoms is particularly preferred because it allows the production of a cured product having excellent resistance to moist heat.

[0031] In the general formula (I), a is preferably an integer of 1 to 4, b is preferably an integer of 0 to 3, and c is preferably an integer of 0 to 3. Among these, a polymerizable composition in which a is an integer of 1 to 2 and c is preferably an integer of 0 to 2 is preferred because it can give a cured product with excellent moist heat resistance and adhesive strength, and a polymerizable composition in which a is 1 and c is 0 is particularly preferred.

[0032] In the present invention, a polymerizable composition in which the structural unit represented by the general formula (I) is a structural unit represented by the following general formula (Ia) is preferred because it gives a cured product with excellent moist heat resistance and adhesive strength.

[0033] [ka] In the formula, R 2 represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms, Y 4 represents an arylene group having 6 to 20 carbon atoms which may have a substituent, Y 5 represents a divalent alkylene group having 1 to 10 carbon atoms, d represents an integer of 1 to 4; e represents an integer of 0 to 3; d+e is 1 to 4.

[0034] Specific examples of the structural units of the epoxy polymer (A1) include the following structural units.

[0035] [ka]

[0036] In the present invention, a polymerizable composition having an epoxy equivalent of the epoxy polymer (A1) of 180 g / eq or more and less than 350 g / eq is preferred because it cures at a low exposure dose and gives a cured product with excellent heat resistance. The epoxy equivalent is more preferably 200 g / eq or more and less than 325 g / eq, and particularly preferably 220 g / eq or more and 300 g / eq.

[0037] As the epoxy polymer (A1), commercially available products can be used, such as Epiclon N-660, Epiclon N-730, and Epiclon N-865 (manufactured by DIC), NC-2000L, NC-3000, and NC-7000L (manufactured by Nippon Kayaku Co., Ltd.).

[0038] The monofunctional epoxy compound (A2) is a compound having only one epoxy group and no alicyclic epoxy group. The alicyclic epoxy group refers to a cycloalkene oxide structure. The monofunctional epoxy compound (A2) includes a monofunctional aromatic epoxy compound and a monofunctional aliphatic epoxy compound.

[0039] The monofunctional aromatic epoxy compound is an epoxy compound having only one epoxy group and an aromatic ring, and specific examples thereof include monoglycidyl ethers of monohydric phenols having at least one aromatic ring, such as phenol, cresol, and butylphenol, or alkylene oxide adducts thereof; glycidyl esters of benzoic acids, such as benzoic acid, toluic acid, and naphthoic acid; and epoxidized products of styrene oxide.

[0040] A monofunctional aliphatic epoxy compound is an epoxy compound that has only one epoxy group and does not have an aromatic ring or an alicyclic epoxy group, and examples thereof include glycidyl ethers of aliphatic alcohols, glycidyl esters of alkylcarboxylic acids, etc. Representative compounds include allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, C12-13 mixed alkyl glycidyl ethers, monoglycidyl ethers of higher aliphatic alcohols, and glycidyl esters of higher fatty acids.

[0041] In the present invention, a polymerizable composition in which the epoxy equivalent of the monofunctional epoxy compound (A2) is 150 g / eq. or more and less than 500 g / eq. is preferred because it has low viscosity, is easy to handle, and gives a cured product with excellent moist heat resistance. The epoxy equivalent is more preferably 160 g / eq. or more and less than 475 g / eq., and particularly preferably 170 g / eq. or more and less than 450 g / eq.

[0042] The monofunctional epoxy compound (A2) may be a commercially available product, such as Denacol EX-121, Denacol EX-141, Denacol EX-142, Denacol EX-145, Denacol EX-146, Denacol EX-147, or Denacol EX-171 (manufactured by Nagase ChemteX Co., Ltd.), Adekaglycirol ED-501, Adekaglycirol ED-502, Adekaglycirol ED-509S, or Adekaglycirol ED-529 (manufactured by ADEKA), Epolite M-1230 (manufactured by Kyoeisha Chemical Co., Ltd.), Epogose 2EH (manufactured by Yokkaichi Synthetic Co., Ltd.), or Cardolite LITE513E (manufactured by Cardolite Co., Ltd.).

[0043] A polymerizable composition containing 50 parts by mass or more but less than 99 parts by mass of the cationically polymerizable compound (A) per 100 parts by mass of the solid content of the polymerizable composition is preferred because it gives a cured product with excellent wet heat resistance, more preferably 75 parts by mass or more but less than 97 parts by mass, and particularly preferably 85 parts by mass or more but less than 95 parts by mass. The solid content here refers to the parts by mass of the total polymerizable composition excluding the parts by mass of the solvent described below.

[0044] In the present invention, a polymerizable composition containing 5 to less than 50 parts by mass of epoxy polymer (A1) per 100 parts by mass of cationically polymerizable compound (A) is preferred because it gives a cured product with excellent moist heat resistance. The content of epoxy polymer (A1) is particularly preferably 10 to less than 40 parts by mass in order to achieve both low viscosity and heat resistance.

[0045] In the present invention, a polymerizable composition containing 0.5 to 50 parts by mass of a monofunctional epoxy compound (A2) per 100 parts by mass of a cationically polymerizable compound (A) is preferred because it provides a cured product with low viscosity, excellent handleability, and excellent moist heat resistance. The content of the monofunctional epoxy compound (A2) is more preferably 1.0 to 40 parts by mass, and particularly preferably 5 to 30 parts by mass to achieve both low viscosity and heat resistance.

[0046] The cationically polymerizable compound (A) preferably contains an aliphatic epoxy compound (A3), since this gives a polymerizable composition with low viscosity and excellent handleability.

[0047] The aliphatic epoxy compound (A3) is a compound having at least two epoxy groups and having no aromatic ring or alicyclic epoxy group, and examples thereof include polyfunctional epoxy compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, and polyglycidyl esters of aliphatic long-chain polybasic acids. Representative compounds include glycidyl ethers of polyhydric alcohols such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, tetraglycidyl ether of sorbitol, hexaglycidyl ether of dipentaerythritol, diglycidyl ether of polyethylene glycol, and diglycidyl ether of polypropylene glycol; polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as propylene glycol, trimethylolpropane, and glycerin; diglycidyl esters of aliphatic long-chain dibasic acids; epoxidized soybean oil; and epoxidized polybutadiene.

[0048] The aliphatic epoxy compound (A3) may be a commercially available product, and examples thereof include Denacol EX-810, Denacol EX-861, Denacol EX-211, Denacol EX-252, Denacol EX-614, Denacol EX-313, Denacol EX-512, and Denacol EX-321 (manufactured by Nagase ChemteX), Adeka Resin EP-4088S, Adeka Glysilol ED-503G, Adeka Glysilol ED-506, Adeka Glysilol ED-523T, and Adeka Glysilol ED-505 (manufactured by ADEKA), Epolite 40E, Epolite 70P, Epolite 1500NP, Epolite 1600, Epolite 80MF, Epolite 100MF, and Epolite 4000 (manufactured by Kyoeisha Chemical Co., Ltd.).

[0049] In the present invention, a polymerizable composition containing 10 parts by mass or more and less than 50 parts by mass of an aliphatic epoxy compound (A3) per 100 parts by mass of a cationically polymerizable compound (A) is preferred because it has low viscosity and excellent handleability. The content of the aliphatic epoxy compound (A3) is more preferably 15 parts by mass or more and 30 parts by mass or less in order to achieve both low viscosity and heat resistance.

[0050] The cationically polymerizable compound (A) preferably contains an oxetane compound (A4) because a polymerizable composition with good curability can be obtained.

[0051] The oxetane compound (A4) is a compound having at least one oxetanyl group and no epoxy group. Examples of the compound having one oxetanyl group include 3-ethyl-3-(hydroxymethyl)oxetane, 3-ethyl-3-(methoxymethyl)oxetane, 3-ethyl-3-(hexyloxymethyl)oxetane, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, 3-ethyl-3-(cyclohexyloxymethyl)oxetane, and 3-ethyl-3-(4-hydroxybutyloxymethyl)oxetane. Examples of the compound having two oxetanyl groups include 3,7-bis(3-oxetanyl)-5-oxa-nonane and 1,4-bis[(3-ethyl-3-oxetaniyl)]. 1,4-bis(3-ethyl-3-oxetanylmethoxy)butane, 1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, 3-ethyl-3-(3-ethyl-3-oxetanylmethyloxymethyl)oxetane, xylylene bisoxetane, and the like.

[0052] The oxetane compound (A4) may be a commercially available product, such as Aron Oxetane OXT-121, OXT-221, EXOH, POX, OXA, OXT-101, OXT-211, or OXT-212 (manufactured by Toagosei Co., Ltd.), or Ethanacol OXBP or OXTP (manufactured by Ube Industries, Ltd.).

[0053] In the present invention, a polymerizable composition containing 1 to 30 parts by mass of an oxetane compound (A4) per 100 parts by mass of a cationically polymerizable compound (A) is preferred because it has good curability. The content of the oxetane compound (A4) is more preferably 15 to 25 parts by mass in order to achieve good curability, adhesiveness, and heat resistance.

[0054] The cationically polymerizable compound (A) may contain an aromatic epoxy compound (A5). The aromatic epoxy compound (A5) is a compound other than the epoxy polymer (A1) that has an aromatic ring and at least two epoxy groups. Examples include glycidyl ethers of bisphenol A, bisphenol F, or compounds obtained by further adding alkylene oxide to these; glycidyl ethers of aromatic compounds having two or more phenolic hydroxyl groups, such as resorcinol, hydroquinone, and catechol; polyglycidyl ethers of aromatic compounds having two or more alcoholic hydroxyl groups, such as benzenedimethanol, benzenediethanol, and benzenedibutanol; and glycidyl esters of polybasic aromatic compounds having two or more carboxylic acids, such as phthalic acid, terephthalic acid, and trimellitic acid.

[0055] As the aromatic epoxy compound (A5), commercially available products can also be used, and examples thereof include Denacol EX-201 (manufactured by Nagase ChemteX), Oxol PG-100, Oxol EG-200, Oxol EG-280, Oxol CG-500 (manufactured by Osaka Gas Chemicals), Epiclon 830, Epiclon 840 (manufactured by DIC), Adeka Resin EP-4100, Adeka Resin EP-4900 (manufactured by ADEKA), and YX-4000 (manufactured by Mitsubishi Chemical).

[0056] The cationically polymerizable compound (A) preferably contains an alicyclic epoxy compound (A6), since this gives a polymerizable composition that has low viscosity, is easy to handle, and has good curability.

[0057] The alicyclic epoxy compound (A6) is a compound having a cycloalkene oxide structure and not having an aromatic ring. The cycloalkene oxide structure is a structure in which an aliphatic ring and an epoxy ring share a part of the ring structure, such as a cyclohexene oxide structure or a cyclopentene oxide structure, which is obtained by epoxidizing a cyclohexene ring-containing compound or a cyclopentene ring-containing compound with an oxidizing agent.

[0058] Among the alicyclic epoxy compounds, examples of compounds having one cycloalkene oxide structure include 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, dicyclopentadiene diepoxide, dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1-epoxyethyl-3,4-epoxycyclohexane, and 1,2-epoxy-2-epoxyethylcyclohexane.

[0059] The alicyclic epoxy compound (A6) can be a commercially available product, and examples thereof include CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2000, CELLOXIDE 3000 (manufactured by Daicel), and LDO (manufactured by Symrise).

[0060] In the present invention, a polymerizable composition containing 0.5 to 15 parts by mass of an alicyclic epoxy compound (A6) per 100 parts by mass of a cationically polymerizable compound (A) is preferred because it has low viscosity, is easy to handle, and has good curability. The content of the alicyclic epoxy compound (A6) is preferably 1 to 10 parts by mass in order to achieve good curability, adhesiveness, and heat resistance.

[0061] The polymerizable composition of the present invention contains a cationic photopolymerization initiator (B). The photocationic polymerization initiator (B) may be any compound capable of releasing a substance that initiates cationic polymerization upon irradiation with light. However, a double salt, which is an onium salt that releases a Lewis acid upon irradiation with light, or a derivative thereof is preferred, as this allows a polymerizable composition with excellent curability to be obtained.

[0062] Examples of double salts that are onium salts or derivatives thereof include salts of a cation and anion represented by the following general formula (i). [A] m+ [B] m- (i)

[0063] where cation [A]m+ is an onium, and its structure can be represented, for example, by the following general formula: [(R 21 ) x Q] m+ (ii) In the above general formula (ii), R 21 represents an organic group having 1 to 60 carbon atoms and may contain any number of atoms other than carbon atoms. x represents an integer of 1 to 5. x R 21 are each independently the same or different. x R 21 At least one of these represents the organic group having an aromatic ring. Q represents an atom or an atomic group selected from the group consisting of S, N, Se, Te, P, As, Sb, Bi, O, I, Br, Cl, F, and N=N. Also, a cation [A] m+ When the valence of Q in the formula is q, the relationship m=xq must hold. However, N=N is treated as having a valence of 0.

[0064] Also, anions [B] m- is preferably a halide complex, and the structure thereof can be represented, for example, by the following general formula (iii). [LX y ] m- (iii) In the above general formula (iii), L represents a metal or metalloid that is the central atom of the halide complex, and is B, P, As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn, or Co. X represents a halogen atom. y represents an integer of 3 to 7. In addition, the anion [B] m- When the valence of L in the compound is p, the relationship m=yp must hold.

[0065] The anion [LX y ] m- A specific example is tetrakis(pentafluorophenyl)borate [(C6F5)4B] -, tetrafluoroborate (BF4) - , hexafluorophosphate (PF6) - , hexafluoroantimonate (SbF6) - , hexafluoroarsenate (AsF6) - , hexachloroantimonate (SbCl6) - , tris(pentafluoromethyl)trifluorophosphate ion (FAP anion), and the like.

[0066] Also, anions [B] m- may be a structure represented by the following general formula (iv): [LX y-1 (OH)] m- (iv) Here, L, X, and b are the same as above. Other anions include perchlorate ions (ClO4) - , trifluoromethyl sulfite ion (CF3SO3) - , fluorosulfonate ion (FSO3) - , toluenesulfonate anion, trinitrobenzenesulfonate anion, camphorsulfonate, nonafluorobutanesulfonate, hexadecafluorooctane sulfonate, tetraarylborate, tetrakis(pentafluorophenyl)borate, and the like.

[0067] Among these onium salts, sulfonium salts of a sulfonium cation such as a triphenylsulfonium cation represented by Group I or Group II below and an anion such as hexafluorophosphate, hexafluoroantimonate, or tetrakis(pentafluorophenyl)borate are preferred in the present invention, as they result in a polymerizable composition with superior curability.

[0068] [ka]

[0069] [ka]

[0070] In the present invention, a composition containing 1 to 20 parts by mass of the cationic photopolymerization initiator (B) per 100 parts by mass of the cationic polymerizable compound (A) is preferred because it has good curability. The content of the cationic photopolymerization initiator (B) is more preferably 2 to 10 parts by mass in order to achieve both curability and heat resistance.

[0071] As the cationic photopolymerization initiator (B), commercially available products can be used, for example, KAYARAD PCI-220, KAYARAD PCI-620 (manufactured by Nippon Kayaku Co., Ltd.), UVI-6990 (manufactured by Dow Chemical Co., Ltd.), ADEKA ADEKA ARCLES SP-150, ADEKA OPTOMER SP-170 (manufactured by ADEKA), CI-5102, CIT-1370, CIT-1682, CIP-1866S, CIP-2048S, CIP-2064S (manufactured by Nippon Soda Co., Ltd.), DP I-101, DPI-102, DPI-103, DPI-105, MPI-103, MPI-105, BBI-101, BBI-102, BBI-103, BBI-105, TPS-101, TPS-102, TPS-103, TPS-105, MDS-103, MDS-105, DTS-102, DTS-103 (manufactured by Midori Chemical), PI-2074 (manufactured by Rhodia), CPI-100P (manufactured by San-Apro), and the like.

[0072] The polymerizable composition of the present invention can use a solvent capable of dissolving or dispersing each component. The solvent is a compound that is liquid at 25°C and 1 atmosphere and does not fall into the above-mentioned categories. Examples of the solvent include ketones such as methyl ethyl ketone, methyl amyl ketone, diethyl ketone, acetone, methyl isopropyl ketone, methyl isobutyl ketone, cyclohexanone, and 2-heptanone; ether solvents such as ethyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane, propylene glycol monomethyl ether, and dipropylene glycol dimethyl ether; ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, cyclohexyl acetate, ethyl lactate, dimethyl succinate, and Texanol; cellosolve solvents such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; alcohol solvents such as methanol, ethanol, iso- or n-propanol, iso- or n-butanol, and amyl alcohol; and ethylene glycol monomethyl acetate, ethylene glycol monoethyl acetate, and propylene glycol-1-monomethyl ether-2-acetate (PGMEA). ), ether ester solvents such as dipropylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, and ethoxyethyl propionate; BTX solvents such as benzene, toluene, and xylene; aliphatic hydrocarbon solvents such as hexane, heptane, octane, and cyclohexane; terpene hydrocarbon oils such as turpentine oil, D-limonene, and pinene; paraffin solvents such as mineral spirits, Swazol #310 (Cosmo Matsuyama Oil Co., Ltd.), and Solvesso #100 (Exxon Chemical Co., Ltd.); carbon tetrachloride halogenated aliphatic hydrocarbon solvents such as chloroform, trichloroethylene, methylene chloride, and 1,2-dichloroethane; halogenated aromatic hydrocarbon solvents such as chlorobenzene; propylene carbonate, carbitol-based solvents, aniline, triethylamine, pyridine, acetic acid, acetonitrile, carbon disulfide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and water, and these solvents can also be used as a mixed solvent of two or more of them.

[0073] To the polymerizable composition of the present invention, various resin additives may be added, as needed, such as other monomers, other polymerization initiators, inorganic fillers, organic fillers, colorants such as pigments and dyes, photosensitizers, antifoaming agents, thickeners, surfactants, leveling agents, flame retardants, thixotropic agents, diluents, plasticizers, stabilizers, polymerization inhibitors, ultraviolet absorbers, antioxidants, antistatic agents, flow adjusters, and adhesion promoters. However, it is preferable that the polymerizable composition of the present invention does not contain a radical polymerizable compound or a radical polymerization initiator, since this would result in poor adhesion.

[0074] The content of the solvent in the polymerizable composition of the present invention is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and particularly preferably 10 parts by mass or less, relative to 100 parts by mass of the polymerizable composition. When the content of the solvent is within the above range, damage to the substrate is small, which is preferable.

[0075] The total amount of optional components other than the cationically polymerizable compound (A) and the photocationic polymerization initiator (B) in the polymerizable composition of the present invention varies depending on the application of the present invention, etc., but from the viewpoint of further enhancing the effects of the present invention, it is preferably 20 parts by mass or less per 100 parts by mass of the cationically polymerizable compound (A), and particularly preferably 10 parts by mass or less in order to achieve both the improvement in performance due to the addition of the optional components and the features of the present invention.

[0076] Specific applications of the polymerizable composition of the present invention include optical materials such as eyeglasses and imaging lenses, paints, coating agents, lining agents, inks, resists, liquid resists, adhesives, printing plates, insulating varnishes, insulating sheets, laminates, printed circuit boards, sealants for semiconductor devices, LED packages, liquid crystal injection ports, organic electroluminescence (EL) devices, optical elements, electrical insulation, electronic components, and separation membranes, molding materials, putties, glass fiber impregnating agents, fillers, passivation films for semiconductors and solar ponds, interlayer insulating films, protective films, prism lens sheets used in the backlights of liquid crystal display devices, Fresnel lens sheets used in screens of projection televisions, and lens portions of lens sheets such as lenticular lens sheets, or backlights using such sheets, optical lenses such as microlenses, optical elements, optical connectors, optical waveguides, and casting agents for optical shaping. For example, substrates to which the polymerizable composition can be applied as a coating agent include metal, wood, rubber, plastic, glass, and ceramic products. In particular, the polymerizable composition of the present invention is useful as an adhesive because it has low viscosity and can give a cured product having excellent resistance to moist heat and adhesive strength. [Example]

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0078] [Examples 1 to 18, Comparative Examples 1 to 7] Polymerizable compositions were prepared by mixing the components according to the formulations shown in Tables 1 to 3, and the viscosity, optical properties, initial adhesion, adhesiveness, moist heat resistance, and heat resistance were evaluated. The evaluation results are shown in Tables 1 to 3. The components in the table are as follows:

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] <Evaluation method> (viscosity) The viscosity μ of the polymerizable compositions obtained in the Examples and Comparative Examples immediately after production was measured using a viscometer (a cone-plate type viscometer (TVE-22L manufactured by Toki Sangyo Co., Ltd.)) in an atmosphere of 25°C, and evaluated according to the following criteria. A lower viscosity is preferable because it is easier to handle, and a rating of S to B indicates that there is no problem with handleability. S: μ≦35 mPa·s A: 35 mPa·s<μ≦60 mPa·s B: 60 mPa·s<μ≦150 mPa·s C: 150 mPa·s<μ

[0087] (Optical properties) The polymerizable compositions obtained in the examples and comparative examples were each applied to a glass plate in a thickness of 50 μm, and another sheet of glass was attached to the glass plate. The resulting glass plate was then irradiated with 1000 mJ / cm 2 of high-pressure Hg lamp. 2Irradiated with light and heated at 150 °C for 1 hour to obtain test pieces. The b* of the obtained test pieces was measured using an ultraviolet-visible-near-infrared spectrophotometer V-670 (manufactured by JASCO Corporation), and evaluated according to the following criteria. Since the smaller the b*, the better the optical properties, it is preferable. When it is A to B, it can be judged that the optical properties are particularly excellent. A: b* ≤ 5 B: 5 < b* ≤ 10 or less C: 10 < b*

[0088] (Initial adhesiveness) For the test pieces obtained in the same manner as the test pieces used for the evaluation of optical properties, after standing for 3 minutes under the conditions of 30 °C, 50% RH, and atmospheric pressure, the test pieces were cut into a width of 2.0 cm to obtain evaluation samples. Using this evaluation sample, a 90° peel test was conducted and evaluated according to the following criteria. Since the higher the initial adhesiveness, the better the curability, it is preferable. When it is S to B, it can be judged that the curability is particularly excellent. S: 2.5 N / 2 cm or more or substrate failure A: 1.5 N / 2 cm or more and less than 2.5 N / 2 cm B: 0.5 N / 2 cm or more and less than 1.5 N / 2 cm C: Less than 0.5 N / 2 cm

[0089] (Adhesiveness) For the test pieces obtained in the same manner as the test pieces used for the evaluation of optical properties, after leaving them for 12 hours under the conditions of 30 °C, 50% RH, and atmospheric pressure, the test pieces were cut into a width of 2.0 cm to obtain evaluation samples. Using this evaluation sample, a 90° peel test was conducted and evaluated according to the following criteria. Since the higher the adhesiveness, the better the adhesiveness as an adhesive, it is preferable. If it is S to A, it can be judged that it is particularly useful as an adhesive. S: 2.5 N / 2 cm or more or substrate failure A: 1.5 N / 2 cm or more and less than 2.5 N / 2 cm B: 0.5 N / 2 cm or more and less than 1.5 N / 2 cm C: Less than 0.5 N / 2 cm

[0090] (Moisture and heat resistance) Test pieces obtained in the same manner as the test pieces used to evaluate the optical properties were left for 500 hours under conditions of 85°C, 85% RH, and atmospheric pressure, and then cut into 2.0 cm widths to obtain evaluation samples. A 90° peel test was performed using these evaluation samples, and they were evaluated according to the following criteria. Higher adhesion is preferable because it indicates better resistance to moist heat, and a rating of S to A indicates particularly excellent resistance to moist heat. S:1.5N / 2cm or more A: 1.0N / 2cm or more, less than 1.5N / 2cm B: 0.5N / 2cm or more, less than 1.0N / 2cm C: Less than 0.5N / 2cm

[0091] (Heat resistance) The b* of test specimens obtained in the same manner as the test specimens used to evaluate the optical properties was measured using a V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation). After leaving the specimens for 500 hours under conditions of 200°C, 85% RH, and atmospheric pressure, the b* was measured again, and the difference Δb* from the initial b* was calculated and evaluated according to the following criteria. The smaller the Δb*, the better the heat resistance, and a rating of S to A is considered to be particularly excellent in heat resistance. S:Δb*<3 A:3≦Δb*<5 B:5≦Δb*<8 C:8≦Δb*

[0092] [Table 1]

[0093] [Table 2]

[0094] [Table 3]

[0095] As shown in Tables 1 to 3, the polymerizable composition of the present invention has low viscosity, excellent handleability, and excellent curability. Furthermore, the cured product of the polymerizable composition of the present invention has excellent adhesive strength, moist heat resistance, and heat resistance, making it particularly useful as an adhesive.

Claims

1. Contains a cationically polymerizable compound (A) and a photocationic polymerization initiator (B), the cationically polymerizable compound (A) contains an epoxy polymer (A1) and a monofunctional epoxy compound (A2), A photocurable adhesive containing a polymerizable composition in which the epoxy polymer (A1) is a polymer having a structural unit represented by the following general formula (I): 【Chemical 1】 In the formula, Ar represents a benzene ring or a naphthalene ring. R １ represents a halogen atom, a hydroxyl group, a nitro group, a cyano group, a hydrocarbon group of 1 to 20 carbon atoms which may have a substituent, a heterocyclic group of 2 to 10 carbon atoms which may have a substituent, a heterocycle-containing group of 3 to 30 carbon atoms which may have a substituent, or a group in which one or more methylene groups in the hydrocarbon group of 1 to 20 carbon atoms have been substituted with a divalent group selected from the following <Group A>, or a group in which one or more methylene groups in the heterocycle-containing group of 3 to 30 carbon atoms have been substituted with a divalent group selected from the following <Group A>, Y １ represents an unsubstituted arylene group having 6 to 20 carbon atoms, Y ２ and Y ３ each independently represents a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, or a group in which one or more methylene groups in the hydrocarbon group having 1 to 20 carbon atoms have been substituted with a divalent group selected from the following <Group A>, a represents an integer of 0 to 4; b represents an integer of 0 to 4; c represents an integer of 0 to 4; a+b is 1 to 4, and a+b+c is 1 to 4. <Group A>: -O-, -CO-, -COO-, -OCO-, -NR １１ -, -NR １２ CO-, -S- R １１ and R １２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.

2. 2. The photocurable adhesive according to claim 1, wherein the cationically polymerizable compound (A) contains an aliphatic epoxy compound (A3).

3. 3. The photocurable adhesive according to claim 1, wherein the cationically polymerizable compound (A) contains an oxetane compound (A4).

4. The photocurable adhesive according to any one of claims 1 to 3, wherein the cationically polymerizable compound (A) contains an alicyclic epoxy compound (A6).

5. 5. The photocurable adhesive according to claim 1, wherein the epoxy equivalent of the epoxy polymer (A1) is 180 g / eq. or more and less than 350 g / eq.

6. 6. The photocurable adhesive according to claim 1, wherein the monofunctional epoxy compound (A2) has an epoxy equivalent of 150 g / eq. or more and less than 500 g / eq.

7. 7. The photocurable adhesive according to claim 1, wherein the content of the epoxy polymer (A1) is 5 parts by mass or more and less than 50 parts by mass per 100 parts by mass of the cationically polymerizable compound (A).

8. 8. The photocurable adhesive according to claim 1, wherein the content of the monofunctional epoxy compound (A2) is 0.5 parts by mass or more and less than 50 parts by mass per 100 parts by mass of the cationically polymerizable compound (A).

9. A method for producing a cured product, comprising the step of irradiating the photocurable adhesive according to any one of claims 1 to 8 with active energy rays or heating the adhesive.

10. A cured product of the photocurable adhesive according to any one of claims 1 to 8.

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