JP2003277352A - Sulfonium salt, cationic polymerization initiator, curable composition, curing method and cured material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a sulfonium salt which has excellent solubility in a cationic polymerizable compound, does not emit a smell from a cured material obtained by cationic polymerization and has high polymerization activity by heat, light or an active energy beam such as electron beam, X-ray, etc. <P>SOLUTION: The sulfonium salt is represented by general formula [I] [R<SP>1</SP>s are each a 1-18C alkyl group or the like; m is an integer of 0-7; R<SP>1</SP>s are mutually the same or different; R<SP>2</SP>is an alkyl group which may be substituted with a fixed group and has 9-24 carbon atoms; R<SP>3</SP>is hydrogen, a halogen, a 1-8C alkyl group, a 1-8C alkoxy group or a phenyl group; A is a 6-20C aryl group which may be substituted with a fixed group, a 1-18C alkyl group or alkoxy group; X<SP>-</SP>is a nonnucleophilic anion]. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel sulfonium salt, a cationic polymerization initiator, a curable composition, a curing method and a cured product. Specifically, heat, light or an active energy ray such as an electron beam or an X-ray is applied to cure a cation polymerizable compound, a sulfonium salt, a cation polymerization initiator containing the sulfonium salt, and a cation polymerization initiator. The present invention relates to a curable composition containing an agent, a method for curing a cationically polymerizable compound using the cationic polymerization initiator, and a cured product obtained by the curing method.

[0002]

2. Description of the Related Art Conventionally, various sulfonium salts have been used as a polymerization initiator used when curing a cationically polymerizable compound such as an epoxy compound under the action of active energy rays such as heat, light or electron rays and X-rays. Proposed (JP-A-50-151997, JP-A-50-158680,
See JP-A-2-178303). However, JP-A-5
The triarylsulfonium salts described in JP-A No. 0-151997 and JP-A No. 50-158680 are known as polymerization initiators having high photopolymerization initiation ability, but have low solubility in cationically polymerizable compounds, and However, there is a problem in that a cured product obtained by cationic polymerization produces an odor derived from a decomposition product of the polymerization initiator. In addition, JP-A-2
The dialkylbenzylsulfonium salt described in JP-A-178303 and the like is useful as a thermal polymerization initiator, but its performance as a photopolymerization initiator is extremely low.

A phenacylsulfonium salt having a naphthalene nucleus has been reported in JP-A-9-118663 as a cationic polymerization initiator which has solved these problems, but the sulfonium salt is dissolved in a cationically polymerizable compound. The sex is still insufficient. A dialkylphenacylsulfonium salt has been proposed as a compound having improved solubility in a cationically polymerizable compound (US Pat. No. 6,031,014), but this compound has low performance as a photopolymerization initiator.

[0004]

DISCLOSURE OF THE INVENTION The present invention has good solubility in a cationically polymerizable compound, has no odor from a cured product obtained by cationic polymerization, and has activity of heat, light and electron beams, X-rays and the like. Sulfonium salt having high polymerization activity by energy rays, cationic polymerization initiator containing the sulfonium salt, curable composition containing the cationic polymerization initiator, method for curing cationically polymerizable compound using the cationic polymerization initiator, and It is an object to provide a cured product obtained by the curing method.

[0005]

The sulfonium salt of the present invention is a sulfonium salt represented by the general formula [1].

[Chemical 2] [In the formula, R ¹ represents an alkyl group having 1 to 18 carbon atoms, a hydroxy group, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, and 1 carbon atom. ~
An alkylcarbonyl group having 19 carbon atoms, an arylcarbonyl group having 7 to 11 carbon atoms, an alkoxycarbonyl group having 2 to 19 carbon atoms,
Aryloxycarbonyl group having 7 to 11 carbon atoms, 2 carbon atoms
~ 19 acyloxy groups, C6-10 arylthio groups,
Represents a cyano group, a nitro group or a halogen, and m represents 0 to 7
And R ¹ may be the same as or different from each other. R ² represents an alkyl group which may be substituted with a group selected from hydroxy, alkylcarbonyl, arylcarbonyl, cyano, aryl, alkoxy, aryloxy, nitro and halogen, and has 9 to 24 carbon atoms. R ³ represents hydrogen, halogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group. A has 6 to 6 carbon atoms which may be substituted with a group selected from alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, arylthio, aryl, aryloxy, cyano, nitro and halogen. 20 represents an aryl group, hydroxy, alkylcarbonyl, arylcarbonyl, cyano, aryl, alkoxy, aryloxy, nitro, and an optionally substituted alkyl group or alkoxy group having 1 to 18 carbon atoms. X ⁻ represents a non-nucleophilic anion. Further, the cationic polymerization initiator of the present invention is characterized by containing at least one kind of the sulfonium salt, and the curable composition of the present invention comprises a cationic polymerizable compound and the cationic polymerization initiator. The method for curing a cationically polymerizable compound of the present invention is characterized in that the curable composition is cured by the action of heat, light or active energy rays. The cured product of the present invention is obtained by the curing method.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION First, the sulfonium salt of the present invention represented by the general formula [1] will be described in detail below. In the general formula [1], R ¹ is an alkyl group having 1 to 18 carbon atoms,
Hydroxy group, C1-18 alkoxy group, C6
~ 10 aryl groups, C6-10 aryloxy groups,
An alkylcarbonyl group having 1 to 19 carbon atoms, an arylcarbonyl group having 7 to 11 carbon atoms, an alkoxycarbonyl group having 2 to 19 carbon atoms, an aryloxycarbonyl group having 7 to 11 carbon atoms, an acyloxy group having 2 to 19 carbon atoms, It represents an arylthio group having 6 to 10 carbon atoms, a cyano group, a nitro group or halogen, m represents an integer of 0 to 7, and R ^1's may be the same or different. Of these, those in which m of R ¹ is 0 are preferable.

Examples of the alkyl group having 1 to 18 carbon atoms for R ¹ include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl and octadecyl, isopropyl,
Examples thereof include branched alkyl groups such as isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl and isohexyl, and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. Examples of the alkoxy group having 1 to 18 carbon atoms of R ¹ include groups such as methoxy, ethoxy, propoxy, butoxy, hexyloxy, decyloxy, dodecyloxy. Examples of the aryl group having 6 to 10 carbon atoms for R ¹ include groups such as phenyl and naphthyl.
Examples of the aryloxy group having 6 to 10 carbon atoms of R ¹ include groups such as phenoxy and naphthyloxy. Examples of the alkylcarbonyl group having 1 to 19 carbon atoms of R ¹ include groups such as acetyl, propionyl, butanoyl, isobutanoyl, heptanoyl, octanoyl, decanoyl, dodecanoyl, octadecanoyl and the like. Examples of the arylcarbonyl group having 7 to 11 carbon atoms of R ¹ include groups such as benzoyl and naphthoyl. The above-mentioned carbon number of R ¹ is 2
Examples of the alkoxycarbonyl group of ~ 19 include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl,
Examples include groups such as octyloxycarbonyl, tetradecyloxycarbonyl, octadecyloxycarbonyl and the like. Examples of the C 7-11 aryloxycarbonyl group of R ¹ include groups such as phenoxycarbonyl and naphthoxycarbonyl. Examples of the acyloxy group having 2 to 19 carbon atoms of R ¹ include groups such as acetoxy, ethylcarbonyloxy, propylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy and octadecylcarbonyloxy. The carbon number of R ¹ is 6
Examples of the arylthio group of to 10 include groups such as phenylthio and naphthylthio. Examples of the halogen of R ¹ include fluorine, chlorine, bromine, iodine and the like.

In the general formula [1], R ² represents an alkyl group which may be substituted with a group selected from hydroxy, alkylcarbonyl, arylcarbonyl, cyano, aryl, alkoxy, aryloxy, nitro and halogen. The number is 9-24. When the carbon number of R ² is 8 or less, the solubility in the cationically polymerizable compound becomes insufficient. Further, when the carbon number of R ² is 25 or more, the solubility in the cationically polymerizable compound is improved, but the cationic polymerization initiating ability is deteriorated. R ² is an unsubstituted carbon number 9 to
When it is an alkyl group of 24, examples of R ² include linear or branched alkyl groups such as nonyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl and the like. When R ² is an alkyl group having a substituent, the total number of carbon atoms of the substituent and the alkyl group is 9
R ² may be any as long as it is ˜24. Examples of the alkyl group when R ² has the above substituents include methyl, ethyl, propyl, butyl, pentyl, octyl, decyl,
Examples thereof include linear or branched alkyl groups such as dodecyl, tetradecyl, hexadecyl, octadecyl and the like, and have 1 to 24 carbon atoms. The alkylcarbonyl group which is a substituent of R ² is a group such as acetyl and propionyl and has 1 to 23 carbon atoms. The arylcarbonyl group is a group such as benzoyl or naphthoyl and has 7 to 11 carbon atoms. The aryl group is a group such as phenyl and naphthyl, and has 6 to 10 carbon atoms. The alkoxy group is a group such as methoxy, ethoxy, and propoxy, and has 1 carbon atom.
~ 23. The aryloxy group is a group such as phenoxy or naphthyloxy and has 6 to 10 carbon atoms. Examples of the halogen include fluorine, chlorine, bromine, iodine and the like. Of these, the number of carbon atoms of R ² is preferably 10 to 20, and more preferably 12 to 18 because of its excellent solubility in the cationically polymerizable compound.

In the general formula [1], R ³ represents hydrogen, halogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms or a phenyl group. Examples of the halogen include fluorine, chlorine, bromine, iodine and the like. The carbon number 1
As the alkyl group of ~ 8, straight chain alkyl groups such as methyl, ethyl, propyl, butyl, hexyl and octyl,
Examples thereof include branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl and isohexyl, and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. Examples of the alkoxyl group having 1 to 8 carbon atoms include groups such as methoxy, ethoxy, propoxy, butoxy and hexyloxy.
Of these, hydrogen, a methyl group, an ethyl group and a phenyl group are preferable, and one in which R ³ is hydrogen is particularly preferable.

In the general formula [1], A is a group selected from alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, arylthio, aryl, aryloxy, cyano, nitro and halogen. An optionally substituted aryl group having 6 to 20 carbon atoms, a hydroxy group, an alkylcarbonyl group, an arylcarbonyl group, a cyano group, an aryl group, an alkoxy group, an aryloxy group, a nitro group and a halogen group; 18 represents an alkyl group or an alkoxy group.
Examples of the aryl group having 6 to 20 carbon atoms of A include phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, chrysenyl, naphthacenyl and benzanthracenyl groups.

The aryl group having 6 to 20 carbon atoms of A may have the above-mentioned substituent. Explaining the substituent, the alkyl group is a linear alkyl group such as methyl, ethyl, propyl, butyl, pentyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, isopropyl, isobutyl, sec-butyl, tert-. Butyl, isopentyl, neopentyl, tert
An alkyl group having a branch such as pentyl and isohexyl, cyclopropyl, cyclobutyl, cyclopentyl,
It is a cycloalkyl group such as cyclohexyl and has 1 to 18 carbon atoms. The alkoxy group is a group such as methoxy, ethoxy, propoxy, butoxy, hexyloxy, decyloxy, dodecyloxy, etc., having 1 to 18 carbon atoms.
Is. The alkylcarbonyl group is a group such as acetyl, propionyl, butanoyl, isobutanoyl, heptanoyl, octanoyl, decanoyl, dodecanoyl, octadecanoyl, etc., and has 1 to 18 carbon atoms. The arylcarbonyl group is a group such as benzoyl and naphthoyl and has 7 to 11 carbon atoms. The alkoxycarbonyl group is a group such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, octyloxycarbonyl, tetradecyloxycarbonyl, octadecyloxycarbonyl, etc., and has 2 to 19 carbon atoms. The aryloxycarbonyl group is a group such as phenoxycarbonyl and naphthoxycarbonyl, which has 7 to 1 carbon atoms.
Is 1. The acyloxy group is a group such as acetoxy, ethylcarbonyloxy, propylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, octadecylcarbonyloxy and the like, and has 2 carbon atoms.
Is ~ 19. The arylthio group is a group such as phenylthio or naphthylthio and has 6 to 10 carbon atoms. The aryl group is a group such as phenyl and naphthyl, and has 6 to 10 carbon atoms. The aryloxy group is a group such as phenoxy or naphthyloxy and has 6 to 10 carbon atoms. Examples of the halogen include fluorine, chlorine, bromine, iodine and the like.

As the C 1-18 alkyl group of A,
Methyl, ethyl, propyl, butyl, pentyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl,
Linear alkyl groups such as octadecyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl,
Neopentyl, tert-pentyl, branched alkyl groups such as isohexyl, cyclopropyl, cyclobutyl,
Examples thereof include cycloalkyl groups such as cyclopentyl and cyclohexyl. Further, examples of the alkoxy group having 1 to 18 carbon atoms of A include groups such as methoxy, ethoxy, propoxy, butoxy, hexyloxy, decyloxy, dodecyloxy.

The alkyl group and the alkoxy group having 1 to 18 carbon atoms of A may have the above-mentioned substituents. Explaining the substituent, the alkylcarbonyl group is a group such as acetyl and propionyl and has 1 to 11 carbon atoms. Further, the arylcarbonyl group is a group such as benzoyl and naphthoyl and has 7 carbon atoms.
~ 11, the aryl group is a group such as phenyl, naphthyl, etc., the carbon number is 6 to 10, the alkoxy group is a group such as methoxy, ethoxy, propoxy, etc., the carbon number is 1 to 1
0, the aryloxy group is a group such as phenoxy and naphthyloxy, the carbon number is 6 to 10, the halogen is
Fluorine, chlorine, bromine, iodine and the like.

Of these, the preferred group as A is an aryl group having 6 to 20 carbon atoms, which is excellent in the ability to initiate photopolymerization, and particularly a phenyl group. When A is an aryl group having 21 or more carbon atoms, the solubility in the cationically polymerizable compound becomes insufficient.

In the general formula [1], it is a non-nucleophilic anion.
X^-As SbF₆ ^-, AsF₆ ^-, PF₆ ^-, BF_Four ^-, B (C₆F5)_Four ^-
Etc. Of these, especially SbF₆ ^-, PF₆ ^-, B (C
₆F_Five) _Four ^-Is preferable because of its excellent photopolymerization initiation ability.

The sulfonium salt of the present invention can be produced by the following reaction, for example, based on the method described in Japan Chemical Journal, 87 , (5), 74 (1966).

[Chemical 3]

The above reaction is carried out in a polar solvent such as acetonitrile, ethyl acetate, tetrahydrofuran, dioxane, ethanol, acetone, methyl ethyl ketone, chloroform and dichloromethane at a temperature from room temperature to about the boiling point of each solvent for 1 hour to several days. . After the reaction is completed,
The precipitated inorganic salt (AgB) is filtered off and the solvent is removed to obtain the sulfonium salt of the present invention as a solid or viscous liquid. These can be purified by washing with a suitable organic solvent or by recrystallization, if necessary.

The sulfonium salt of the present invention can be produced by the following reaction, for example, based on the method described in J. Org. Chem., 32 , 2580 (1967).

[Chemical 4]

The above reaction is carried out at room temperature to 15 times in an organic solvent such as acetonitrile, tetrahydrofuran, dioxane, ethanol, acetone or the like without a solvent or if necessary.
It is performed at a temperature of about 0 ° C. for 1 hour to several tens of hours. After completion of the reaction, the reaction solution and alkali metal non-nucleophilic anion salt MX
^{(M +: Li +, Na} +, K + , such as _{^{.X -: SbF 6 -, AsF}} 6 -, PF 6 -, BF
_{^{4 -, B (C 6 F}} 5) 4 - and the like. The aqueous solution of 1) is added and stirred to carry out a metathesis reaction. The precipitated solid is filtered off or the separated oily substance is extracted with an organic solvent to remove the solvent, whereby the sulfonium salt of the present invention is obtained as a solid or viscous liquid. These can be purified by washing with a suitable organic solvent or by recrystallization, if necessary.

The structure of the obtained sulfonium salt can be identified by a general analytical method (for example, nuclear magnetic resonance spectrum, infrared absorption spectrum, elemental analysis, etc.). The structure of the sulfonium salt described in the present specification was identified especially by a nuclear magnetic resonance spectrum. Specifically, the chemical shift of the proton of α-carbon bonded to the positively charged sulfur atom can be easily identified by moving to the lower magnetic field side compared to that of the raw material.

Table 1 shows typical examples of the sulfonium salt of the present invention represented by the above general formula [1]. However, X in the formula ^-
Is _{^{SbF 6 -, AsF 6 -,}} PF 6 -, BF 4 -, B (C 6 F 5) 4 - shows a non-nucleophilic anion, and the like.

[0022]

[Table 1]

The sulfonium salt of the present invention is used as a cationic polymerization initiator and may be used alone or in combination with other cationic polymerization initiators. That is, the cationic polymerization initiator of the present invention contains at least one kind of the above-mentioned sulfonium salt of the present invention. As the other cationic polymerization initiator, all known ones can be used in combination, and examples thereof include a sulfonium salt, an iodonium salt, a phosphonium salt, a pyridinium salt, and an iron-arene complex. When used in combination with other cationic polymerization initiators, the ratio is 10
Normally, 1 to 2 other cationic polymerization initiators are used per 0 part by weight.
The amount is 00 parts by weight, preferably 5 to 100 parts by weight.

Other cationic polymerization initiators will be described. Examples of the sulfonium salt include triphenylsulfonium hexafluorophosphate and bis [4
-(Diphenylsulfonio) -phenyl] sulfide bishexafluorophosphate, bis [4- (diphenylsulfonio) -phenyl] sulfide bishexafluoroantimonate, 4-di (p-toluyl) sulfonio-4-tert-butylphenyl Carbonyl-diphenyl sulfide hexafluorophosphate, 4-di (p-
Toluyl) sulfonio-4-tert-butylphenylcarbonyl-diphenyl sulfide hexafluoroantimonate, 7-di (p-toluyl) sulfonio-2-isopropyl-thioxanthone hexafluorophosphate, 7-di (p-toluyl) sulfonio-2- Isopropyl-thioxanthone hexafluforoantimonate and the like, and JP-A-7-61964 and JP-A-8-165.
290, US Pat. No. 4,231,951, US Pat. No. 4
Examples thereof include aromatic sulfonium salts described in No. 256828 and the like.

Examples of the iodonium salt as a cationic polymerization initiator include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, and JP-A-6- Aromatic iodonium salts described in U.S. Pat. No. 184170, U.S. Pat. No. 4,256,828 and the like can be mentioned.

Examples of the phosphonium salt as a cationic polymerization initiator include tetraphenylphosphonium hexafluorophosphate, tetraphenylphosphonium hexafluoroantimonate, and the like, and JP-A-6-
Examples thereof include aromatic phosphonium salts described in 157624 and the like. Examples of the pyridinium salt that is a cationic polymerization initiator include, for example, Patent Publication No. 251.
Examples thereof include pyridinium salts described in JP-A No. 9480 and JP-A No. 5-222112.

The curable composition of the present invention comprises the cationic polymerization initiator of the present invention and a cationic polymerizable compound. Examples of the cationically polymerizable compound to which the cationic polymerization initiator of the present invention can be applied include epoxy compounds, vinyl ether compounds, oxetane compounds, ethylenically unsaturated compounds such as styrene, and further spiro orthoester compounds, bicyclo Examples include cyclic ethers such as orthoester compounds and spiro orthocarbonate compounds.

Examples of the epoxy compound to which the cationic polymerization initiator of the present invention can be applied include aromatic epoxy compounds, alicyclic epoxy compounds and aliphatic epoxy compounds. As the aromatic epoxy compound,
Mono- and polyhydric phenols having at least one aromatic ring, or polyglycidyl ethers of alkylene oxide adducts thereof, such as phenol, bisphenol A, bisphenol F, or polyglycidyl compounds in which alkylene oxides are further added. Ether, phenol novolac type epoxy resin, o-, p-,
Examples thereof include m-cresol novolac type epoxy resin.

Examples of the alicyclic epoxy compound include a cyclohexene oxide-containing compound or a cyclopentene oxide-containing compound obtained by epoxidizing at least one cyclohexene ring- or cyclopentene ring-containing compound with an oxidizing agent. For example, 3,4-epoxycyclohexylmethyl-3,4-
Epoxycyclohexanecarboxylate, 3,4-epoxy-1-methylcyclohexyl-3,4-epoxy-1-methylhexanecarboxylate, 6-methyl-
3,4-epoxycyclohexylmethyl-6-methyl-
3,4-epoxycyclohexanecarboxylate,
3,4-epoxy-3-methylcyclohexylmethyl-
3,4-epoxy-3-methylcyclohexanecarboxylate, 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5 5-Spiro-3,4-epoxy) cyclohexane-metadioxane, bis (3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxy-6
-Methylcyclohexylcarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylenebis (3,4-epoxycyclohexanecarboxylate) and the like.

As the aliphatic epoxy compound, a polyglycidyl ether of an aliphatic polyhydric alcohol or an alkylene oxide adduct thereof, a polyglycidyl ester of an aliphatic long-chain polybasic acid, a homopolymer synthesized by vinyl polymerization of glycidyl acrylate or glycidyl methacrylate is used. Examples thereof include polymers, copolymers synthesized by vinyl polymerization of glycidyl acrylate or glycidyl methacrylate and other vinyl monomers, and the like. Typical aliphatic epoxy compounds include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, glycerin triglycidyl ether, and trimethylolpropane triglycidyl. Ether, tetraglycidyl ether of sorbitol, hexaglycidyl ether of dipentaerythritol, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, etc. One or two of aliphatic polyhydric alcohols such as glycidyl ether of polyhydric alcohol, propylene glycol, trimethylolpropane and glycerin. Polyglycol ether of polyether polyol obtained by adding the above alkylene oxide, diglycidyl ester of aliphatic long-chain dibasic acid, monoglycidyl ether of aliphatic higher alcohol, glycidyl ester of higher fatty acid, large epoxidation Soybean oil, octyl epoxy stearate, butyl epoxy stearate, epoxidized polybutadiene and the like can be mentioned.

Examples of the vinyl ether compound to which the cationic polymerization initiator of the present invention can be applied include methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, 2-chloroethyl vinyl ether, and 2-phenoxyethyl vinyl ether. , 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, stearyl vinyl ether, 2-acetoxyethyl vinyl ether, diethylene glycol monovinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether and other alkyl vinyl ether compounds, aryl vinyl ether, 2-metacroyl Oxyethyl vinyl ether, 2-acloy Alkenyl vinyl ether compounds such as oxyethyl vinyl ether, phenyl vinyl ethers, aryl vinyl ether compounds such as p-methoxyphenyl vinyl ether, 1,4-butanediol divinyl ether, triethylene glycol divinyl ether, 1,4-benzenedivinyl ether, hydroquinone divinyl ether, Examples thereof include polyfunctional vinyl ether compounds such as cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, dipropylene divinyl ether, and hexanediol divinyl ether.

The oxetane compound to which the cationic polymerization initiator of the present invention can be applied is, for example, 3
-Ethyl-3-hydroxymethyloxetane, 3- (meth) aryloxymethyl-3-ethyloxetane,
(3-Ethyl-3-oxetanylmethoxy) methylbenzene, 4-fluoro- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, 4-methoxy-
[1- (3-Ethyl-3-oxetanylmethoxy) methyl] benzene, [1- (3-Ethyl-3-oxetanylmethoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, Isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl-3-oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, ethyldiethylene glycol (3- Ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyl (3-
Ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3)
-Oxetanylmethyl) ether, 2-tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-)
Oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-) Oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl)
Ether, pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, 3,7-bis ( 3-oxetanyl) -5-oxanonane, 3,3- (1,3- (2-methylenyl) propanediylbis (oxymethylene)) bis- (3-ethyloxetane), 1,4-bis [(3-ethyl -3-Oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl]
Ethane, 1,3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether,
Dicyclopentenyl bis (3-ethyl-3-oxetanylmethyl) ether, triethylene glycol bis (3
-Ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether,
Trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3-ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane,
Pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-Ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol Hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone modified dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, dito Trimethylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, E
O-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether,
EO modified hydrogenated bisphenol A bis (3-ethyl-3-
Oxetanylmethyl) ether, PO modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl)
Ether, EO modified bisphenol F (3-ethyl-3
-Oxetanylmethyl) ether and the like.

The ethylenically unsaturated compound to which the cationic polymerization initiator of the present invention can be applied includes cations such as styrene, vinylcyclohexene, isobutylene, polybutadiene and their derivatives, N-vinylcarbazole, N-vinylpyrrolidone. Examples include polymerizable nitrogen-containing compounds.

Examples of the spiro orthoester compound to which the cationic polymerization initiator of the present invention can be applied include
1,4,6-trioxaspiro [4,4] nonane, 2-methyl-1,4,6-trioxaspiro [4,4] nonane,
1,4,6-trioxaspiro [4,5] decane and the like can be mentioned.

The bicycloorthoester compound to which the cationic polymerization initiator of the present invention can be applied is 1-phenyl-4-ethyl-2,6,7-trioxabicyclo [2,2,2] octane, 1-ethyl-4-hydroxymethyl-2,6,7-trioxabicyclo [2,2,
2] Octane and the like can be mentioned.

Examples of the spiro orthocarbonate compound to which the cationic polymerization initiator of the present invention can be applied include 1,5,7,11-tetraoxaspiro [5,5] undecane, 3,9-dibenzyl-1, Examples include 5,7,11-tetraoxaspiro [5,5] undecane.

When the cationically polymerizable compound is cured using the sulfonium salt of the present invention, the cationically polymerizable compound may be used alone or in combination of two or more. The sulfonium salt of the present invention is particularly an epoxy compound,
It is suitable for curing oxetane compounds and vinyl ether compounds.

The ratio of the sulfonium salt of the present invention to the cationically polymerizable compound used is not particularly limited, but 0.01 to 20 parts by weight, preferably 0.1 to 20 parts by weight of the sulfonium salt of the present invention is used with respect to 100 parts by weight of the cationically polymerizable compound. 10 parts by weight. If the amount of this sulfonium salt is less than 0.01 parts by weight, the polymerization of the cationically polymerizable compound will be insufficient, and if it is more than 20 parts by weight, the properties of the cured product may deteriorate. The suitable use ratio of the sulfonium salt of the present invention is the nature of the cationically polymerizable compound, the type and irradiation amount of active energy rays, desired curing time, temperature, humidity, coating thickness, and the amount of other cationic polymerization initiator used. Etc. are determined by considering various factors.

In order to facilitate the dissolution of the sulfonium salt of the present invention in the cationically polymerizable compound, a solvent which does not inhibit cationic polymerization, such as propylene carbonate, ethylene carbonate, carbitol, carbitol acetate, γ, is prepared in advance. -A sulfonium salt may be dissolved in butyrolactone or the like. The proportion of the solvent used is usually 50 to 300 with respect to 100 parts by weight of the sulfonium salt of the present invention.
Parts by weight, preferably 75 to 200 parts by weight.

The curable composition of the present invention contains the above-mentioned sulfonium salt and a cationically polymerizable compound, and if necessary, a pigment, a filler, an antistatic agent, a flame retardant, an antifoaming agent. Additives such as flow control agents, sensitizers, and light stabilizers can be added. Examples of the pigment include titanium oxide, iron oxide, inorganic pigments such as carbon black, azo-based pigments,
Known organic pigments such as cyanine-based, phthalocyanine-based, and quinacridone-based organic pigments can be used. The mixing ratio of the pigment is 100 parts by weight of the curable composition of the present invention,
Usually, it is 1 to 500 parts by weight, preferably 1 to 100 parts by weight.

As the above-mentioned filler, conventionally known ones such as fused silica, crystalline silica, calcium carbonate, aluminum oxide, zirconium oxide, aluminum hydroxide, magnesium carbonate, mica, talc, calcium silicate and lithium aluminum silicate can be used. Can be mentioned. The blending ratio of the filler is usually 1 to 1000 parts by weight, preferably 1 to 500 parts by weight with respect to 100 parts by weight of the curable composition of the present invention.

Examples of the antistatic agent include glycerin fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, N, N-bis (2-hydroxyethyl) alkylamine, polyoxyethylene alkylamine, polyoxy. Non-ionic activators such as ethylene alkyl amine fatty acid ester and alkyl diethanol amide, anionic activators such as alkyl sulfonate, alkyl benzene sulfonate and alkyl phosphate, cationic activators such as tetraalkyl ammonium salt and trialkyl benzyl ammonium salt Activator, amphoteric activator such as alkyl betaine, alkyl imidazolium betaine, methoxy polyethylene glycol (meth) acrylate, quaternary ammonium salt group-containing (meth) acrylate, Conventionally known copolymers such as quaternary ammonium salt group-containing maleimide and the like can be mentioned. The mixing ratio of the antistatic agent is usually 0.1 to 50 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the curable composition of the present invention.

As the flame retardant, antimony trioxide,
Inorganic flame retardants such as antimony pentoxide, tin oxide, tin hydroxide, molybdenum oxide, zinc borate, barium metaborate, red phosphorus, aluminum hydroxide, magnesium hydroxide, calcium aluminate, tetrabromophthalic anhydride, hexabromobenzene Examples include conventionally known bromine flame retardants such as decabromobiphenyl ether and phosphoric acid flame retardants such as tris (tribromophenyl) phosphate. The mixing ratio of the flame retardant, the curable composition 10 of the present invention
1 to 100 parts by weight, preferably 1 to 0 parts by weight
~ 50 parts by weight.

As the antifoaming agent, isopropanol,
Alcohols such as n-butanol, octadecyl alcohol, hexadecyl alcohol, metal soaps such as calcium stearate and aluminum stearate, phosphoric acid esters such as tributyl phosphate, fatty acid esters such as glycerin monolaurate, polyalkylene glycol, etc. Conventionally known ones such as polyethers, dimethyl silicone oil, organically modified silicone oil, fluorosilicone oil, and silicones such as silica / silicone corn compound are listed. The blending ratio of the defoaming agent is 100 parts by weight of the curable composition of the present invention.
Usually, it is 0.1 to 20 parts by weight, preferably 0.1 to 10 parts by weight.

As the flow regulator, conventionally known ones such as hydrogenated castor oil type, polyethylene oxide type, organic bentonite type, colloidal silica type, amide wax type, metal soap type and acrylic acid ester polymer type are used. Can be mentioned. The mixing ratio of the flow regulator is usually 0.1 to 30 parts by weight, preferably 0.1 to 15 parts by weight, based on 100 parts by weight of the curable composition of the present invention.

Examples of the sensitizer include conventionally known ones such as anthracene, phenylcyclohexyl ketone, thioxanthone, phenothiazine, chlorothioxanthone, xanthone, diphenylanthracene, rubrene, carbazole, naphthol, perylene, tetracene and derivatives thereof. . When these sensitizers are used, the compounding ratio is usually 1 to 200 parts by weight, preferably 5 to 100 parts by weight, based on 100 parts by weight of the sulfonium salt of the present invention.

As the above-mentioned light stabilizer, conventionally known ones such as benzotriazole-based, benzophenone-based, salicylate-based, cyanoacrylate-based ultraviolet absorption type, hindered amine-based radical trapping type, nickel complex-based quenching type, etc. Is mentioned. The mixing ratio of the light stabilizer is 100 parts by weight of the curable composition of the present invention.
Usually, it is 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight.

A solvent for diluting can be added to the curable composition of the present invention within a range that does not impair the cationic polymerization. The addition ratio of the solvent is usually 1 to 100 parts by weight, preferably 5 to 80 parts by weight, based on 100 parts by weight of the curable composition of the present invention. As the solvent, for example,
Toluene, xylene, anisole, cyclohexanone,
Diethylene glycol dimethyl ether, propylene glycol methyl ether acetate, butyl cellosolve, butyl acetate, amyl acetate, diethylene glycol and the like can be mentioned.

The curable composition of the present invention may contain non-reactive resins and (meth) acrylic acid ester compound for modification. The mixing ratio of them is
With respect to 100 parts by weight of the curable composition of the present invention, usually 10 to 2
The amount is 00 parts by weight, preferably 10 to 100 parts by weight. Examples of the non-reactive resins include acrylic polymers,
Examples thereof include polyurethane polymers, polyester elastomers, polyvinyl chloride polymers, acrylonitrile rubber and the like. As the (meth) acrylic acid ester compound,
For example, oligomers such as epoxy (meth) acrylate, urethane (meth) acrylate, polyester poly (meth) acrylate, which are reaction products of epoxy resin such as bisphenol A type epoxy resin or novolac type epoxy resin and (meth) acrylic acid, 2-hydroxy (meth)
Examples thereof include monomers such as acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol tri (meth) acrylate. When blending the (meth) acrylic acid ester compound, it is preferable to use a photoradical polymerization initiator. Examples of the photoradical polymerization initiator include conventionally known ones such as 1-hydroxycyclohexyl phenyl ketone, acetophenone dimethyl ketol, and benzoyl methyl ether. The proportion of the radical photopolymerization initiator used is usually 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the (meth) acrylic acid ester compound.

The curable composition of the present invention can be prepared by a method such as mixing, dissolving or kneading the above-mentioned cationically polymerizable compound, cationic polymerization initiator and photo-radical polymerization initiator at room temperature or if necessary. it can.

The curable composition of the present invention can be cured to a touch-free state or a solvent-insoluble state after 0.1 seconds to several minutes by irradiation with light or an active energy ray. The active energy ray may be any one as long as it has the energy to induce the decomposition of the sulfonium salt of the present invention, but is preferably a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp metal halide lamp, a xenon lamp, carbon. Arc lamp,
A fluorescent lamp or the like is used. Also, semiconductor laser, argon laser, laser light such as He-Cd laser, electron beam,
Highly active energy rays such as X-rays and radiation can also be used. The irradiation time of the active energy ray depends on the intensity of the active energy ray, but usually 0.1 to 10 seconds is sufficient at room temperature. However, for relatively thick coatings, it may be preferable to spend more time. 0.1 seconds to several minutes after irradiation with active energy rays, most curable compositions are dried by touch by cationic polymerization, but if necessary, after irradiation with active energy rays, room temperature to 150 ° C.
It is also possible to cure by heating for several seconds to several hours.

The curable composition of the present invention can also be cured by heating. The heat curing is carried out by heating at 80 to 250 ° C., preferably 100 to 200 ° C. for several minutes to several hours.

Specific uses of the curable composition of the present invention include paints, coating agents, inks, resists, adhesives, molding materials, casting materials, putties, glass fiber impregnating agents, sealing agents, stereolithography. Things etc. are mentioned.

[0054]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following.

Example 1 Synthesis of 2-naphthyldodecylphenacylsulfonium hexafluorophosphate (Compound No. 1 in Table 1) 33 parts by weight of 2-naphthyldodecyl sulfide, 20 parts by weight of phenacyl bromide, silver hexafluorophosphate 25 parts by weight and 650 parts by weight of dichloromethane were mixed and reacted at room temperature to 35 ° C. for 4 days. The reaction solution was filtered to remove silver bromide, and the solvent was removed from the filtrate under reduced pressure using an evaporator. The obtained viscous oily substance was washed with ethanol and dried under reduced pressure at room temperature to obtain 51 parts by weight of 2-naphthyldodecylphenacylsulfonium hexafluorophosphate (yield = 86%). ¹ H-NMR (d ₆ -acetone): δ7.5 to 8.9 (12
H), δ6.1 (2H), δ4.1 (2H), δ1.9 (2H), δ1.5
(2H), δ1.1 to 1.3 (16H), δ0.8 (3H)

Example 2 Synthesis of 2-naphthyltetradecylphenacylsulfonium hexafluorophosphate (Compound No. in Table 1
2) 2-naphthyltetradecylphenacylsulfonium hexafluorophosphate 54 was reacted in the same manner as in Example 1 except that 36 parts by weight of 2-naphthyltetradecyl sulfide was used instead of 2-naphthyldodecyl sulfide of Example 1. Part by weight was obtained (yield = 86%). ¹ H-NMR (d ₆
-Acetone): δ7.5 to 8.9 (12H), δ6.1 (2H), δ4.
1 (2H), δ1.9 (2H), δ1.5 (2H), δ1.1 to 1.3 (20
H), δ0.8 (3H)

Example 3 Synthesis of 2-naphthyloctadecylphenacylsulfonium hexafluorophosphate (Compound No. in Table 1
3) The reaction was performed in the same manner as in Example 1 except that 41 parts by weight of 2-naphthyloctadecyl sulfide was used instead of 2-naphthyldodecyl sulfide of Example 1, and 58 parts by weight of 2-naphthyloctadecylphenacylsulfonium hexafluorophosphate. Was obtained (yield = 85%). ¹ H-NMR (d ₆
-Acetone): δ7.5 to 8.9 (12H), δ6.1 (2H), δ4.
1 (2H), δ1.9 (2H), δ1.5 (2H), δ1.1 to 1.3 (28
H), δ0.8 (3H)

Examples 1 to 1 relating to the sulfonium salt of the present invention
3 and Comparative Examples 1 to 3 described below were subjected to the following tests, and the evaluation results are shown in Table 2.

[0059]

[Table 2] * 1: 2-naphthylmethylphenacylsulfonium hexafluorophosphate * 2: Triarylsulfonium hexafluorophosphate (UCC, trade name, UVI-6990, 50% propylene carbonate solution) * 3: Decylmethylphenacylsulfonium hexafluoro Phosphate * 4: VE-1; cyclohexanedimethanol divinyl ether (CHVE) * 5: VE-2; 3,6,9,12-tetraoxatetradeca-1,1
3-diene (DVE-3) * 6: EP-1; 3,4-epoxycyclohexylmethyl-3,
4-epoxycyclohexanecarboxylate (UCC, trade name, UVR-6110)

Test Method <Solubility> The cationically polymerizable compounds (VE-
1, VE-2, EP-1) sulfonium salt in pure
After adding 0% by weight and mixing at room temperature, the appearance was visually judged.

<Photocurable> Alicyclic epoxy compound EP-1
100 parts by weight of sulfonium salt γ-butyrolactone 50
% Solution was added and mixed uniformly. This compounded solution is applied to a polyester film with an applicator so that the film thickness is 40 μm, and after photocuring under the following conditions,
The pencil hardness of the coating film was measured. (Condition-1) UV irradiation conditions ・ UV irradiation device: Belt conveyor type UV irradiation device (manufactured by Fusion UV Systems) ・ Lamp: 2kW (100W / cm) parallel light type metal halide lamp, irradiation distance 18cm ・ Conveyor speed: 4m / Minute / irradiation frequency: 1 time

(Condition-2) The condition-1 is the same as the condition-1 except that the irradiation number is changed to three times.

<Odor of Coating Film> The odor of the cured coating film obtained above was evaluated by the sense of smell.

Evaluation Results From the results shown in Table 2, the sulfonium salt of the present invention is soluble,
It can be seen that it is excellent in any evaluation regarding the photocurability and the residual odor of the coating film of the cured product.

[0065]

INDUSTRIAL APPLICABILITY The sulfonium salt of the present invention has a good solubility in a cationically polymerizable compound, and also improves the curability of the cationically polymerizable compound by the action of active energy rays such as heat, light, electron beams and X rays. It is excellent and has high performance as a cationic polymerization initiator. Furthermore, since the cured product obtained using the sulfonium salt of the present invention has no odor, the sulfonium salt of the present invention is a cationically polymerizable paint, coating agent, ink, resist, adhesive, molding material, casting It is suitable as a material, a putty, a glass fiber impregnating agent, a filling agent, a cationic polymerization initiator for a photosensitive resin for stereolithography and the like.

Continued front page    (72) Inventor Takeshi Endo             2-4-33 Monto-cho, Yonezawa City, Yamagata Prefecture Mansho             Interrace 3F-8 F-term (reference) 4H006 AA01 AA03 AB40                 4H048 AA01 AA03 AB40 VA75 VB10                 4J005 AA07 BB02                 4J015 EA05                 4J036 AA01 GA03 HA01

Claims (11)

[Claims] 1. A sulfonium salt represented by the general formula [1]. [Chemical 1] [In the formula, R ¹ represents an alkyl group having 1 to 18 carbon atoms, a hydroxy group, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, and 1 carbon atom. ~
An alkylcarbonyl group having 19 carbon atoms, an arylcarbonyl group having 7 to 11 carbon atoms, an alkoxycarbonyl group having 2 to 19 carbon atoms,
Aryloxycarbonyl group having 7 to 11 carbon atoms, 2 carbon atoms
~ 19 acyloxy groups, C6-10 arylthio groups,
Represents a cyano group, a nitro group or a halogen, and m represents 0 to 7
And R ¹ may be the same as or different from each other. R ² represents an alkyl group which may be substituted with a group selected from hydroxy, alkylcarbonyl, arylcarbonyl, cyano, aryl, alkoxy, aryloxy, nitro and halogen, and has 9 to 24 carbon atoms. R ³ represents hydrogen, halogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a phenyl group. A has 6 to 6 carbon atoms which may be substituted with a group selected from alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, arylthio, aryl, aryloxy, cyano, nitro and halogen. 20 represents an aryl group, hydroxy, alkylcarbonyl, arylcarbonyl, cyano, aryl, alkoxy, aryloxy, nitro, and an optionally substituted alkyl group or alkoxy group having 1 to 18 carbon atoms. X ⁻ represents a non-nucleophilic anion. ] Wherein wherein X ^{- _{SbF 6 -, AsF 6 -,}} PF 6 -, BF 4 - and B
(C ₆ F _{5) 4} ^- anions sulfonium salt according to claim 1, wherein is selected from. 3. The sulfonium salt according to claim 1, wherein A is a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group or a benzanthracenyl group. 4. The sulfonium salt according to claim ¹ , wherein m of R ¹ is 0. 5. The sulfonium salt according to claim 1, wherein R ² has 10 to 20 carbon atoms. 6. The sulfonium salt according to claim 1, wherein R ³ is hydrogen. 7. The sulfonium salt according to claim 1, wherein A is a phenyl group. 8. A cationic polymerization initiator comprising at least one kind of the sulfonium salt according to claim 1. 9. A curable composition comprising a cationically polymerizable compound and the cationic polymerization initiator according to claim 8. 10. The curable composition according to claim 9 is heated,
A method for curing a cationically polymerizable compound, which comprises curing by applying light or an active energy ray. 11. A cured product obtained by the curing method according to claim 10.