JP5706651B2 - Fluorinated alkyl phosphate sulfonium salt, acid generator and curable composition - Google Patents

Description

  The present invention relates firstly to a sulfonium salt, and secondly to an acid generator, more specifically, when an active energy ray such as heat, light, electron beam or X-ray is applied to cure a cationically polymerizable compound. The present invention relates to an acid generator containing a specific sulfonium salt suitable for the above. Thirdly, the present invention relates to a curable composition containing the acid generator and a cured product obtained by curing the curable composition.

  Conventionally, a sulfonium salt is known as a cationic polymerization initiator that cures a cationically polymerizable compound such as an epoxy compound by acting an active energy ray such as heat, light, electron beam, or X-ray (Patent Documents 1 and 2). 3, 4).

By the way, the cationic polymerization initiator described in these specifications contains BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , and SbF ₆ ⁻ as anions, but the cationic polymerization initiation performance varies depending on the type of anion. BF ₄ ⁻ <PF ₆ ⁻ <AsF ₆ ⁻ <SbF ₆ ⁻ in this order. However, good polymerization initiation ability _AsF ⁶ -, SbF ₆ ^- cationic polymerization initiator containing the As, limited use applications from toxicity problems of Sb, SbF ₆ ^- in applications salts were restricted such stereolithography It is only used. Therefore, in general, PF ₆ polymerization initiation ability is poor ^- the salts are utilized, PF ₆ ^- salt, for example, SbF ₆ ^- to obtain the cure rate comparable to salt, the latter 10 times more The amount of unreacted initiator, the solvent used as needed to dissolve the initiator, or the decomposition product of the initiator is increased, and the physical properties of the cured product are impaired. In addition, since the amount of HF produced as a by-product due to decomposition of the initiator is increased, there is a problem that the base material and equipment are easily corroded. Thus free of toxic metals, SbF ₆ ^- cationic polymerization initiator having a cationic polymerization initiating ability comparable to salt has been strongly desired.

As acid generators that meet this problem, acid generators that have the same or similar cation moiety as the present application and have a counter anion other than SbF ₆ (Patent Documents 5, 6, 7, and 8) have been disclosed. Compared to SbF ₆ , the curability is poor and impractical.

JP-A-2-196812 Japanese Patent Laid-Open No. 3-17101 Japanese Patent Laid-Open No. 3-205405 JP-A-3-237107 JP 2006-282633 A JP 2006-96742 A JP 2008-303167 A JP 2010-132614 A

In the above-mentioned background, the first object of the present invention is to provide a new sulfonium salt that does not contain a highly toxic element such as Sb and is excellent in cationic polymerization ability.
A second object of the present invention is a new acid generator comprising a sulfonium salt, which is highly toxic elementally safe such as Sb, excellent in curability, and highly compatible with a cationically polymerizable compound such as an epoxy compound. Is to provide.
The third object of the present invention is to provide a curable composition and a cured product using the acid generator.

  The present inventor has found that a sulfonium salt represented by the following formula (1) is suitable for the above purpose. That is, the present invention provides a sulfonium salt represented by the formula (1).

[In formula (1), R ¹ and R ² each independently represents an alkyl group or an aralkyl group, and R ³ represents hydrogen, an alkyl group, a hydroxy group, a carboxyl group, an alkoxy group, an aryloxy group, an alkylcarbonyl group, an aryl group. Carbonyl group, aralkylcarbonyl group, alkoxycarbonyl group, aryloxycarbonyl group, aralkyloxycarbonyl group, alkylcarbonyloxy group, arylcarbonyloxy group, aralkylcarbonyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, aralkyloxycarbonyl Oxy group, arylthiocarbonyl group, arylthio group, alkylthio group, aryl group, heterocyclic hydrocarbon group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, aryl Represents a sulfonyl group, a hydroxy (poly) alkyleneoxy group, optionally substituted amino group, a cyano group, a nitro group or a halogen atom, m represents the number of R ^3, is an integer of 0 to 5. Rf represents an alkyl group in which 80% or more of hydrogen is substituted with a fluorine atom. b represents the number thereof and is an integer of 1 to 5. Rf may be the same or different. ]

Moreover, this invention is an acid generator characterized by containing said sulfonium salt.

  Moreover, this invention is a curable composition which contains the said acid generator and a cationically polymerizable compound.

  Furthermore, the present invention is a cured product obtained by curing the curable composition.

Since the sulfonium salt of the present invention does not contain a highly toxic element such as Sb, it is safe and excellent in curability and highly compatible with a cationically polymerizable compound such as an epoxy compound.
The acid generator of the present invention is excellent in thermal potential, and can cure the cationically polymerizable compound in a short time at a predetermined temperature without impairing storage stability. The acid generator of the present invention can also be cured by light.
Since the curable composition of this invention contains said acid generator, it is excellent in storage stability, and is excellent in workability | operativity since it is highly reactive.
The cured product of the present invention has high safety because it does not contain highly toxic elements such as Sb.

  Hereinafter, embodiments of the present invention will be described in detail.

In formula (1), among R ^{1 to} R ³ , the alkyl group is a linear alkyl group having 1 to 18 carbon atoms (methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, etc.), a branched alkyl group having 1 to 18 carbon atoms (isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl and isooctadecyl), and cycloalkyl groups having 3 to 18 carbon atoms (such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and 4-decylcyclohexyl).

In the formula (1), among R ¹ and R ² , as the aralkyl group, a lower alkyl group substituted with an aryl group having 6 to 10 carbon atoms (benzyl, 2-methylbenzyl, 1-naphthylmethyl, 2-naphthyl) Methyl and the like).

In the formula (1), the alkoxy group in R ³ is a linear or branched alkoxy group having 1 to 18 carbon atoms (methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy Hexyloxy, decyloxy, dodecyloxy, octadecyloxy and the like).

In Formula (1), examples of the aryloxy group in R ³ include aryloxy groups having 6 to 10 carbon atoms (such as phenoxy and naphthyloxy).

In the formula (1), the alkylcarbonyl group in R ³ is a linear or branched alkylcarbonyl group having 2 to 18 carbon atoms (acetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl 3-methylbutanoyl, octanoyl, decanoyl, dodecanoyl, octadecanoyl, etc.).

In the formula (1), examples of the arylcarbonyl group in R ³ include arylcarbonyl groups having 7 to 11 carbon atoms (such as benzoyl and naphthoyl).

In formula (1), the aralkylcarbonyl group in R ³ is a lower alkylcarbonyl group substituted with an aryl group having 6 to 10 carbon atoms (benzylcarbonyl, 2-methylbenzylcarbonyl, 1-naphthylmethylcarbonyl, 2 -Naphthylmethylcarbonyl and the like).

In the formula (1), as the alkoxycarbonyl group in R ³ , a linear or branched alkoxycarbonyl group having 2 to 18 carbon atoms (methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl) , Butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, octyloxycarbonyl, tetradecyloxycarbonyl, octadecyloxycarbonyl, and the like.

In Formula (1), examples of the aryloxycarbonyl group in R ³ include aryloxycarbonyl groups having 7 to 11 carbon atoms (such as phenoxycarbonyl and naphthoxycarbonyl).

In formula (1), the aralkyloxycarbonyl group in R ³ is a lower alkoxycarbonyl group substituted with an aryl group having 6 to 10 carbon atoms (benzyloxycarbonyl, 2-methylbenzyloxycarbonyl, 1-naphthylmethyl). Oxycarbonyl, 2-naphthylmethyloxycarbonyl, etc.).

In the formula (1), the alkylcarbonyloxy group in R ³ is a linear or branched alkylcarbonyloxy group having 2 to 19 carbon atoms (acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, butylcarbonyl Oxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, octadecylcarbonyloxy and the like.

In the formula (1), examples of the arylcarbonyloxy group in R ³ include arylcarbonyloxy groups having 7 to 11 carbon atoms (such as benzoyloxy and naphthoyloxy).

In formula (1), the aralkylcarbonyloxy group in R ³ is a lower alkylcarbonyl group substituted with an aryl group having 6 to 10 carbon atoms (benzylcarbonyloxy, 2-methylbenzylcarbonyloxy, 1-naphthylmethyl). Carbonyloxy, 2-naphthylmethylcarbonyloxy and the like).

In the formula (1), the alkoxycarbonyloxy group in R ³ is a linear or branched alkoxycarbonyl group having 2 to 18 carbon atoms (methoxycarbonyloxy, ethoxycarbonyloxy, propoxycarbonyloxy). , Isopropoxycarbonyloxy, butoxycarbonyloxy, isobutoxycarbonyloxy, sec-butoxycarbonyloxy, tert-butoxycarbonyloxy, octyloxycarbonyloxy, tetradecyloxycarbonyloxy, octadecyloxycarbonyloxy and the like.

In Formula (1), examples of the aryloxycarbonyloxy group in R ³ include aryloxycarbonyloxy groups having 7 to 11 carbon atoms (such as phenoxycarbonyloxy and naphthoxycarbonyloxy).

In the formula (1), the aralkyloxycarbonyloxy group in R ³ is a lower alkoxycarbonyloxy group substituted with an aryl group having 6 to 10 carbon atoms (benzyloxycarbonyloxy, 2-methylbenzyloxycarbonyloxy, 1-naphthylmethyloxycarbonyloxy, 2-naphthylmethyloxycarbonyloxy and the like).

In Formula (1), examples of the arylthiocarbonyl group in R ³ include arylthiocarbonyl groups having 7 to 11 carbon atoms (such as phenylthiocarbonyl and naphthoxythiocarbonyl).

In the formula (1), the arylthio group in R ³ is an arylthio group having 6 to 20 carbon atoms (phenylthio, 2-methylphenylthio, 3-methylphenylthio, 4-methylphenylthio, 2-chlorophenylthio, 3 -Chlorophenylthio, 4-chlorophenylthio, 2-bromophenylthio, 3-bromophenylthio, 4-bromophenylthio, 2-fluorophenylthio, 3-fluorophenylthio, 4-fluorophenylthio, 2-hydroxyphenylthio 4-hydroxyphenylthio, 2-methoxyphenylthio, 4-methoxyphenylthio, 1-naphthylthio, 2-naphthylthio, 4- [4- (phenylthio) benzoyl] phenylthio, 4- [4- (phenylthio) phenoxy] phenylthio , 4- [4- (Phenylthio O) phenyl] phenylthio, 4- (phenylthio) phenylthio, 4-benzoylphenylthio, 4-benzoyl-2-chlorophenylthio, 4-benzoyl-3-chlorophenylthio, 4-benzoyl-3-methylthiophenylthio, 4-benzoyl 2-methylthiophenylthio, 4- (4-methylthiobenzoyl) phenylthio, 4- (2-methylthiobenzoyl) phenylthio, 4- (p-methylbenzoyl) phenylthio, 4- (p-ethylbenzoyl) phenylthio 4- (p -Isopropylbenzoyl) phenylthio, 4- (p-tert-butylbenzoyl) phenylthio and the like.

In formula (1), the alkylthio group in R ³ is a linear or branched alkylthio group having 1 to 18 carbon atoms (methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, sec-butylthio, tert- Butylthio, pentylthio, isopentylthio, neopentylthio, tert-pentylthio, octylthio, decylthio, dodecylthio, isooctadecylthio and the like.

In the formula (1), examples of the aryl group in R ³ include aryl groups having 6 to 10 carbon atoms (phenyl, tolyl, dimethylphenyl, naphthyl, and the like).

In formula (1), the heterocyclic hydrocarbon group in R ³ is a heterocyclic hydrocarbon group having 4 to 20 carbon atoms (thienyl, furanyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, pyrazinyl, Indolyl, benzofuranyl, benzothienyl, quinolyl, isoquinolyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenothiazinyl, phenazinyl, xanthenyl, thianthenyl, phenoxazinyl, phenoxathiinyl, chromanyl, isochromanyl, dibenzothienyl, xanthonyl, dithiothionyl, etc. ) And the like.

In Formula (1), examples of the aryloxy group in R ³ include aryloxy groups having 6 to 10 carbon atoms (such as phenoxy and naphthyloxy).

In the formula (1), as the alkylsulfinyl group in R ³ , a linear or branched sulfinyl group having 1 to 18 carbon atoms (methylsulfinyl, ethylsulfinyl, propylsulfinyl, isopropylsulfinyl, butylsulfinyl, isobutylsulfinyl, sec -Butylsulfinyl, tert-butylsulfinyl, pentylsulfinyl, isopentylsulfinyl, neopentylsulfinyl, tert-pentylsulfinyl, octylsulfinyl, isooctadecylsulfinyl and the like.

In formula (1), examples of the arylsulfinyl group in R ³ include arylsulfinyl groups having 6 to 10 carbon atoms (such as phenylsulfinyl, tolylsulfinyl, and naphthylsulfinyl).

In formula (1), the alkylsulfonyl group in R ³ is a linear or branched alkylsulfonyl group having 1 to 18 carbon atoms (methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl, neopentylsulfonyl, tert-pentylsulfonyl, octylsulfonyl, octadecylsulfonyl and the like.

In the formula (1), examples of the arylsulfonyl group in R ³ include arylsulfonyl groups having 6 to 10 carbon atoms (phenylsulfonyl, tolylsulfonyl (tosyl group), naphthylsulfonyl, etc.) and the like.

In the formula (1), examples of the hydroxy (poly) alkyleneoxy group in R ³ include a hydroxy (poly) alkyleneoxy group represented by the following formula.
HO (-AO) q-
[AO represents an ethyleneoxy group and / or a propyleneoxy group, and q represents an integer of 1 to 5. ]

In formula (1), the amino group in R ³ includes an amino group (—NH ₂ ) and a substituted amino group having 1 to 15 carbon atoms (methylamino, dimethylamino, ethylamino, methylethylamino, diethylamino, n- Propylamino, methyl-n-propylamino, ethyl-n-propylamino, n-propylamino, isopropylamino, isopropylmethylamino, isopropylethylamino, diisopropylamino, phenylamino, diphenylamino, methylphenylamino, ethylphenylamino, n-propylphenylamino, isopropylphenylamino and the like).

In the formula (1), examples of the halogen atom group in R ³ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the formula (1), R ¹ and R ² are independent of each other, and therefore may be the same as or different from each other.

In the formula (1), m represents the number of R ³ and is an integer of 0 to 5, preferably 0 to 3, more preferably 0 to 2, particularly preferably 0 or 1.

Among the sulfonium salts represented by the formula (1) of the present invention, preferred specific examples include:
Phenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-hydroxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-methoxycarbonyloxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-acetoxy Phenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-benzyloxycarbonyloxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, phenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4- Hydroxyphenyl-methyl-benzylsulfonium tris (Pentafluoroethyl) trifluorophosphate, 4-methoxycarbonyloxyphenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-acetoxyphenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4 -Benzyloxycarbonyloxyphenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate, phenyl-methyl-2-methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-hydroxyphenyl-methyl-2-methyl Benzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-methoxycarbonyloxyphene Ru-methyl-2-methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-acetoxyphenyl-methyl-2-methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-benzyloxycarbonyloxyphenyl-methyl 2-methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, phenyl-methyl-1-naphthylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium tris (penta Fluoroethyl) trifluorophosphate, 4-methoxycarbonyloxyphenyl-methyl-1-naphthylmethylsulfonium tris Ntafluoroethyl) trifluorophosphate, 4-acetoxyphenyl-methyl-1-naphthylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate and 4-benzyloxycarbonyloxyphenyl-methyl-1-naphthylmethylsulfonium tris (pentafluoroethyl) ) Trifluorophosphate.

  As a manufacturing method of the sulfonium salt of this invention, it can manufacture according to the following Reaction Formula.

In addition, R < ¹ > -R < ³ >, Rf, and b in reaction formula are the same as the definition in Formula (1). X ⁻ represents a halogen anion, and M ⁺ represents an alkali metal (such as lithium, sodium and potassium) cation. MX represents a salt of an alkali metal cation and a halogen anion.

That is, a sulfonium halide of formula (2) (see JP-A-3-48654 for the synthesis method) is dissolved or dispersed in an organic solvent such as dichloromethane, and the fluorinated alkyl phosphate anion and alkali metal cation of formula (3) are dissolved in the solution. And the resulting two-layer mixture is stirred at a temperature of 20 to 80 ° C. for 1 to 3 hours, and the sulfonium halide of formula (2) and the fluorine of formula (3) are mixed. After reacting a salt of an alkyl phosphate anion and an alkali metal cation to separate the organic solvent layer, the organic solvent is distilled off to obtain a sulfonium salt of the formula (1).

The chemical structure of the sulfonium salt of the present invention can be determined by a general analytical method (for example, ¹ H-, ¹¹ B-, ¹³ C-, ¹⁹ F-, ³¹ P-nuclear magnetic resonance spectrum, infrared absorption spectrum and / or element). Analysis).

  The sulfonium salt of the present invention is suitable as an acid generator. The acid generator means an acid that is decomposed by heating or light irradiation to generate an acid. The generated acid can be used as a catalyst for curing reaction of epoxide.

  As the acid generator of the present invention, the sulfonium salt of the present invention may be used as it is, or another acid generator may be contained in this.

  When other acid generators are contained, the content (mol%) of the other acid generators is preferably 1 to 100, more preferably 5 to 50, based on the total number of moles of the sulfonium salt of the present invention. is there.

  Other acid generators include conventionally known compounds such as onium salts (sulfonium, iodonium, selenium, ammonium, phosphonium, etc.) and salts of transition metal complex ions with anions.

  The acid generator of the present invention may be dissolved in advance in a solvent that does not inhibit cationic polymerization in order to facilitate dissolution in the cationic polymerizable compound.

  Solvents include carbonates such as propylene carbonate, ethylene carbonate, 1,2-butylene carbonate, dimethyl carbonate and diethyl carbonate; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone and 2-heptanone; ethylene glycol, ethylene glycol Multivalents such as monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol, and dipropylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, or monophenyl ether Alcohols and derivatives thereof; cyclic ethers such as dioxane Class: ethyl formate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl pyruvate, ethyl ethoxyacetate, methyl methoxypropionate, ethyl ethoxypropionate, Methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate And esters such as aromatic hydrocarbons such as toluene and xylene.

  When a solvent is used, the use ratio of the solvent is preferably 15 to 1000 parts by weight, more preferably 30 to 500 parts by weight with respect to 100 parts by weight of the acid generator of the present invention. The solvent to be used may be used independently or may use 2 or more types together.

  The curable composition of this invention is comprised from said acid generator and a cationically polymerizable compound.

  Examples of the cationic polymerizable compound include cyclic ethers (epoxides and oxetanes), ethylenically unsaturated compounds (vinyl ether and styrene, etc.), bicycloorthoesters, spiroorthocarbonates and spiroorthoesters (Japanese Patent Laid-Open No. 11-060996). JP-A 09-302269, JP-A 2003-026993, JP-A 2002-206017, JP-A 11-349895, JP-A 10-212343, JP-A 2000-119306, JP-A 10-67812, JP 2000-186071, JP 08-85775, JP 08-134405, JP 2008-20838, JP 2008-20839, JP 2008-20841, JP 2008-26660, JP 2008-26444. , JP 2 07-277327, photopolymer social gathering “Photopolymer Handbook” (1989, Industrial Research Committee), General Technology Center “UV / EB Curing Technology” (1982, General Technology Center), Radtech Study Group “UV. EB Curing Material "(1992, CMC), Technical Information Association," Hardening Failure / Inhibition Causes in UV Curing and Countermeasures "(2003, Technical Information Association), Coloring Materials, 68, (5), 286-293 (1995), fine chemicals, 29, (19), 5-14 (2000), etc.).

  Known epoxides can be used, and include aromatic epoxides, alicyclic epoxides and aliphatic epoxides.

  Examples of the aromatic epoxide include glycidyl ethers of monovalent or polyvalent phenols (phenol, bisphenol A, phenol novolac and compounds obtained by adducting these alkylene oxides) having at least one aromatic ring.

  As an alicyclic epoxide, a compound obtained by epoxidizing a compound having at least one cyclohexene or cyclopentene ring with an oxidizing agent (3,4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate, etc.) Is mentioned.

  Aliphatic epoxides include aliphatic polyhydric alcohols or polyglycidyl ethers of this alkylene oxide adduct (1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, etc.), aliphatic polybasic acids Examples thereof include polyglycidyl esters (such as diglycidyl tetrahydrophthalate) and epoxidized products of long chain unsaturated compounds (such as epoxidized soybean oil and epoxidized polybutadiene).

As oxetane, known ones can be used. For example, 3-ethyl-3-hydroxymethyloxetane, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3- Oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, oxetanylsilsesquioxetane, phenol novolac oxetane, etc. Is mentioned.

  As the ethylenically unsaturated compound, known cationic polymerizable monomers and the like can be used, and include aliphatic monovinyl ether, aromatic monovinyl ether, polyfunctional vinyl ether, styrene, and cationic polymerizable nitrogen-containing monomer.

  Examples of the aliphatic monovinyl ether include methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, and cyclohexyl vinyl ether.

  Examples of the aromatic monovinyl ether include 2-phenoxyethyl vinyl ether, phenyl vinyl ether and p-methoxyphenyl vinyl ether.

  Examples of the polyfunctional vinyl ether include butanediol-1,4-divinyl ether and triethylene glycol divinyl ether.

  Examples of styrene include styrene, α-methylstyrene, p-methoxystyrene, and p-tert-butoxystyrene.

  Examples of the cationic polymerizable nitrogen-containing monomer include N-vinylcarbazole and N-vinylpyrrolidone.

  Bicycloorthoesters include 1-phenyl-4-ethyl-2,6,7-trioxabicyclo [2.2.2] octane and 1-ethyl-4-hydroxymethyl-2,6,7-trioxabicyclo. -[2.2.2] octane and the like.

  Examples of spiro orthocarbonates include 1,5,7,11-tetraoxaspiro [5.5] undecane and 3,9-dibenzyl-1,5,7,11-tetraoxaspiro [5.5] undecane. It is done.

  Spiro orthoesters include 1,4,6-trioxaspiro [4.4] nonane, 2-methyl-1,4,6-trioxaspiro [4.4] nonane and 1,4,6-trioxas. Examples include pyro [4.5] decane.

Of these cationically polymerizable compounds, epoxide, oxetane and vinyl ether are preferable, epoxide and oxetane are more preferable, and alicyclic epoxide and oxetane are particularly preferable. Moreover, these cationically polymerizable compounds may be used alone or in combination of two or more.

  The content of the acid generator of the present invention in the curable composition is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight with respect to 100 parts of the cationic polymerizable compound. Within this range, the polymerization of the cationically polymerizable compound is further sufficient, and the physical properties of the cured product are further improved. This content is determined by considering various factors such as the nature of the cationically polymerizable compound, the type of energy beam and the irradiation amount, temperature, curing time, humidity, and coating thickness, and is limited to the above range. Not.

  In the curable composition of the present invention, if necessary, known additives (sensitizers, pigments, fillers, antistatic agents, flame retardants, antifoaming agents, flow regulators, light stabilizers, antioxidants) Agents, adhesion promoters, ion scavengers, anti-coloring agents, solvents, non-reactive resins and radical polymerizable compounds).

  The curable composition of the present invention basically does not require a sensitizer, but can contain a sensitizer as necessary to supplement the curability. As such a sensitizer, known sensitizers (JP-A-11-279212 and JP-A-09-183960) can be used, and anthracene {anthracene, 9,10-dibutoxyanthracene, 9,10 -Dimethoxyanthracene, 9,10-diethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 9,10-dipropoxyanthracene, etc.}; pyrene; 1,2-benzanthracene; perylene; tetracene; coronene; thioxanthone { Thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 2,4-diethylthioxanthone}; phenothiazine {phenothiazine, N-methylphenothiazine, N-ethylphenothiazine, N- Xanthone; naphthalene {1-naphthol, 2-naphthol, 1-methoxynaphthalene, 2-methoxynaphthalene, 1,4-dihydroxynaphthalene, 4-methoxy-1-naphthol, etc.}; ketone {dimethoxyacetophenone, Diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4′-isopropyl-2-hydroxy-2-methylpropiophenone, 4-benzoyl-4′-methyldiphenyl sulfide, etc.}; Carbazole {N-phenylcarbazole, N-ethylcarbazole, poly-N-vinylcarbazole and N-glycidylcarbazole and the like}; chrysene {1,4-dimethoxychrysene and 1,4-di-α-methylbenzyloxychrysene and the like}; Phenan Tren {9-hydroxyphenanthrene, 9-methoxyphenanthrene, 9-hydroxy-10-methoxyphenanthrene, 9-hydroxy-10-ethoxyphenanthrene, etc.} and the like.

  When the sensitizer is contained, the content of the sensitizer is preferably 1 to 300 parts by weight, more preferably 5 to 200 parts by weight, with respect to 100 parts of the acid generator.

  Known pigments can be used as the pigment, and examples include inorganic pigments (such as titanium oxide, iron oxide, and carbon black) and organic pigments (such as azo pigments, cyanine pigments, phthalocyanine pigments, and quinacridone pigments).

  When the pigment is contained, the content of the pigment is preferably 0.5 to 400,000 parts by weight, more preferably 10 to 150,000 parts by weight with respect to 100 parts of the acid generator.

  As the filler, known fillers can be used, such as fused silica, crystalline silica, calcium carbonate, aluminum oxide, aluminum hydroxide, zirconium oxide, magnesium carbonate, mica, talc, calcium silicate and lithium aluminum silicate. Can be mentioned.

  When the filler is contained, the content of the filler is preferably 50 to 600,000 parts by weight, more preferably 300 to 200,000 parts by weight with respect to 100 parts of the acid generator.

  As the antistatic agent, known antistatic agents can be used, and examples include nonionic antistatic agents, anionic antistatic agents, cationic antistatic agents, amphoteric antistatic agents, and polymeric antistatic agents. .

  When the antistatic agent is contained, the content of the antistatic agent is preferably 0.1 to 20000 parts by weight, more preferably 0.6 to 5000 parts by weight with respect to 100 parts of the acid generator.

  As the flame retardant, known flame retardants can be used. Inorganic flame retardant {antimony trioxide, antimony pentoxide, tin oxide, tin hydroxide, molybdenum oxide, zinc borate, barium metaborate, red phosphorus, aluminum hydroxide , Magnesium hydroxide, calcium aluminate, etc.}; bromine flame retardant {tetrabromophthalic anhydride, hexabromobenzene, decabromobiphenyl ether, etc.}; and phosphate ester flame retardant {tris (tribromophenyl) phosphate, etc.} It is done.

  When the flame retardant is contained, the content of the flame retardant is preferably 0.5 to 40000 parts by weight, more preferably 5 to 10000 parts by weight with respect to 100 parts of the acid generator.

As the antifoaming agent, known antifoaming agents can be used, such as alcohol defoaming agents, metal soap defoaming agents, phosphate ester defoaming agents, fatty acid ester defoaming agents, polyether defoaming agents, and silicone defoaming agents. And mineral oil defoaming agents.

As the flow control agent, known flow control agents can be used, and examples thereof include hydrogenated castor oil, polyethylene oxide, organic bentonite, colloidal silica, amide wax, metal soap, and acrylate polymer.
As the light stabilizer, known light stabilizers and the like can be used. Ultraviolet absorbing stabilizers {benzotriazole, benzophenone, salicylate, cyanoacrylate and derivatives thereof}; radical scavenging stabilizers {hindered amines, etc.}; and quenching And a type stabilizer {nickel complex etc.}.
As the antioxidant, known antioxidants can be used, and examples include phenolic antioxidants (monophenolic, bisphenolic and polymeric phenolic), sulfur antioxidants and phosphorus antioxidants. It is done.
As the adhesion-imparting agent, a known adhesion-imparting agent can be used, and examples thereof include a coupling agent, a silane coupling agent, and a titanium coupling agent.
As the ion scavenger, known ion scavengers and the like can be used, and organic aluminum (alkoxyaluminum, phenoxyaluminum, etc.) and the like can be mentioned.
Known anti-coloring agents can be used as the anti-coloring agent. In general, antioxidants are effective. Phenol type antioxidants (monophenol type, bisphenol type and high molecular phenol type, etc.), sulfur type oxidation Examples thereof include an inhibitor and a phosphorus-based antioxidant.

  When an antifoaming agent, a flow control agent, a light stabilizer, an antioxidant, an adhesion promoter, an ion scavenger, or a coloring inhibitor is contained, each content is 0 with respect to 100 parts of the acid generator. 0.1 to 20000 parts by weight is preferable, and 0.5 to 5000 parts by weight is more preferable.

  The solvent is not limited as long as it can be used for dissolving the cationic polymerizable compound or adjusting the viscosity of the curable composition, and those mentioned as the solvent for the acid generator can be used.

  When the solvent is contained, the content of the solvent is preferably 50 to 2,000,000 parts by weight, more preferably 200 to 500,000 parts by weight with respect to 100 parts of the acid generator.

  Non-reactive resins include polyester, polyvinyl acetate, polyvinyl chloride, polybutadiene, polycarbonate, polystyrene, polyvinyl ether, polyvinyl butyral, polybutene, hydrogenated styrene butadiene block copolymer, and (meth) acrylic ester co-polymer. Examples include coalescence and polyurethane. The number average molecular weight of these resins is preferably 1,000 to 500,000, and more preferably 5,000 to 100,000 (the number average molecular weight is a value measured by a general method such as GPC).

  When the non-reactive resin is contained, the content of the non-reactive resin is preferably 5 to 400000 parts by weight, more preferably 50 to 150,000 parts by weight with respect to 100 parts of the acid generator.

  When a non-reactive resin is contained, it is desirable to dissolve the non-reactive resin in a solvent in advance in order to facilitate dissolution of the non-reactive resin with the cationic polymerizable compound.

  As radically polymerizable compounds, known {Photopolymer social gathering “Photopolymer Handbook” (1989, Industrial Research Committee), General Technology Center “UV / EB Curing Technology” (1982, General Technology Center), Radtech Research The radical-polymerizable compounds of the “UV / EB Curing Materials” (1992, CMC) edited by the Society and the “Technical Information Association” “Hardening Failure / Inhibition Causes and Countermeasures for UV Curing” (2003, Technical Information Association)} Monofunctional monomers, bifunctional monomers, polyfunctional monomers, epoxy (meth) acrylates, polyester (meth) acrylates and urethane (meth) acrylates can be used.

  When the radically polymerizable compound is contained, the content of the radically polymerizable compound is preferably 5 to 400000 parts by weight, more preferably 50 to 150,000 parts by weight with respect to 100 parts of the acid generator.

  When a radically polymerizable compound is contained, it is preferable to use a radical polymerization initiator that initiates polymerization by heat or light in order to increase the molecular weight of the compound by radical polymerization.

  As the radical polymerization initiator, known radical polymerization initiators can be used, thermal radical polymerization initiators (organic peroxides, azo compounds, etc.) and photo radical polymerization initiators (acetophenone initiators, benzophenone initiators, Michler ketone-based initiator, benzoin-based initiator, thioxanthone-based initiator, acylphosphine-based initiator, etc.).

  When the radical polymerization initiator is contained, the content of the radical polymerization initiator is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 10 parts by weight with respect to 100 parts of the radical polymerizable compound. .

  The curable composition of the present invention comprises a cationically polymerizable compound, an acid generator, and optionally an additive, which are uniformly mixed and dissolved at room temperature (about 20 to 30 ° C.) or optionally heated (about 40 to 90 ° C.). Alternatively, it can be prepared by kneading with three rolls or the like.

The curable composition of the present invention can be cured by heating or irradiation with energy rays to obtain a cured product.
As the energy ray, any energy ray may be used as long as it has an energy that induces decomposition of the sulfonium salt of the present invention, but low pressure, medium pressure, high pressure or ultrahigh pressure mercury lamp, metal halide lamp, LED lamp, xenon lamp, carbon arc lamp, Energy rays in the ultraviolet to visible light region (wavelength: about 100 to about 800 nm) obtained from a fluorescent lamp, a semiconductor solid state laser, an argon laser, a He—Cd laser, a KrF excimer laser, an ArF excimer laser, an F ₂ laser, or the like are preferable. In addition, the radiation which has high energy, such as an electron beam or an X-ray, can also be used for an energy beam.

  The irradiation time of the energy beam is affected by the intensity of the energy beam and the energy beam permeability to the curable composition, but at room temperature (about 20 to 30 ° C.), about 0.1 to 10 seconds is sufficient. . However, when the energy ray permeability is low or the film thickness of the curable composition is large, it may be preferable to spend more time. From 0.1 seconds to several minutes after irradiation with energy rays, most curable compositions are cured by cationic polymerization, but if necessary, after irradiation with energy rays, at room temperature (about 20-30 ° C) to 150 ° C. It is possible to heat and cure after several seconds to several hours.

  As a heating method for curing, for example, a conventionally known method such as heat circulation heating, infrared heating, high-frequency heating or the like can be used.

The heating temperature necessary for curing is not particularly limited as long as curing proceeds sufficiently and does not deteriorate the substrate, but is preferably in the range of 50 to 250 ° C, more preferably in the range of 80 to 200 ° C. Although the heating time depends on the heating temperature, it is preferably several minutes to several hours from the viewpoint of productivity.

  Specific uses of the curable composition of the present invention include paints, coating agents, inks, inkjet inks, positive resists, resist films, liquid resists, negative resists, MEMS resists, positive photosensitive materials, negatives. Type photosensitive material, various adhesives, molding material, casting material, putty, glass fiber impregnating agent, sealing material, sealing material, sealing material, optical semiconductor (LED) sealing material, optical waveguide material, nanoimprint material, Examples thereof include materials for photofabrication and micro stereolithography.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not intending to be limited to this. Unless otherwise specified, “part” means “part by weight” and “%” means “% by weight”.

[Example 1]
Synthesis of 4-hydroxyphenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate 2.97 g (0.01 mol) of 4-hydroxyphenyl-methyl-benzylsulfonium chloride was dispersed in 15 ml of dichloromethane and equimolar 30 g of an aqueous solution containing potassium tris (pentafluoroethyl) trifluorophosphate was mixed at room temperature and stirred for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, then transferred to a rotary evaporator, and the solvent was distilled off to obtain 4-hydroxyphenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate. 74 g was obtained. (Yield 90%)
NMR
3.11 ppm (s, 3H, sulfonium methyl)
4.71 ppm (d, 2H, phenylmethylene)
6.92-7.58 ppm (m, 9H, benzene nucleus)
8.34 ppm (s, 1H, HO)

[Example 2]
Synthesis of 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate 3.18 g (0.01 mol) of 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium chloride in 15 ml of dichloromethane After dispersion, 30 g of an aqueous solution containing equimolar potassium tris (pentafluoroethyl) trifluorophosphate was mixed at room temperature and stirred for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, and then transferred to a rotary evaporator and the solvent was distilled off, whereby 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate was obtained. 6.94 g of was obtained. (Yield 90%)
NMR
3.14 ppm (s, 3H, sulfonium methyl)
4.77 ppm (t, 2H, naphthylmethylene)
6.99 to 8.07 ppm (m, 11H, benzene naphthalene nucleus)
8.32 ppm (s, 1H, HO)

Example 3
Synthesis of 4-acetoxyphenylbenzylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate 6.76 g (0.01 mol) of benzyl-4-hydroxyphenylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate synthesized in Example 1 Is dissolved in 100 ml of acetonitrile, and 1.22 g (0.012 mol) of triethylamine is added at 10 ° C. or less, and 0.95 g (0.012 mol) of acetyl chloride is added dropwise after 30 minutes. After stirring for 3 hours, the triethylamine hydrochloride formed as a by-product was removed by filtration, transferred to a rotary evaporator, and the solvent was distilled off to give 4.70 g of 4-acetoxyphenylbenzylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate. (Yield 65.5%) was obtained.
NMR
2. 20 ppm (s, 3H, acetyl)
3.14 ppm (s, 3H, sulfonium methyl)
4.82 ppm (d, 2H, phenylmethylene)
7.01 to 7.83 ppm (m, 9H, benzene nucleus)

Example 4
Synthesis of 4-hydroxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate 1.92 g (0.01 mol) of 4-hydroxyphenyldimethylsulfonium chloride is dispersed in 15 ml of dichloromethane and equimolar tris (pentafluoroethyl) trifluoro 30 g of an aqueous solution containing potassium rophosphate was mixed at room temperature and stirred for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, and then transferred to a rotary evaporator and the solvent was distilled off to obtain 5.86 g of 4-hydroxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate. . (Yield 93%)
NMR
3.13 ppm (s, 6H, sulfonium methyl)
6.91-7.59 ppm (dd, 4H, benzene nucleus)
8.33 ppm (s, 1H, HO)

Example 5
Synthesis of 4-acetoxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate 6.00 g (0.01 mol) of 4-hydroxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate synthesized in Example 4 was acetonitrile. Dissolve in 100 ml, add 1.22 g (0.012 mol) of triethylamine at 10 ° C. or less, and after 30 minutes, add 0.95 g (0.012 mol) of acetyl chloride dropwise. After stirring for 3 hours, the triethylamine hydrochloride formed as a by-product was removed by filtration, transferred to a rotary evaporator and the solvent was distilled off, whereby 4.40 g of 4-acetoxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate ( Yield 68.4%) was obtained.
NMR
2.19ppm (s, 3H, acetyl)
3.18 ppm (s, 6H, sulfonium methyl)
7.20-7.89 ppm (dd, 4H, benzene nucleus)

[Comparative Example 1]
4-hydroxyphenyl - methyl - Synthesis of 4-hydroxyphenyl benzyl sulfonium hexafluoroantimonate - methyl - benzyl sulfonium chloride 2.97g (0.01 mole) was dispersed in dichloromethane 15 ml, aqueous solution containing KSbF ₆ equimolar 30 g was mixed at room temperature and stirred as it was for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, then transferred to a rotary evaporator and the solvent was distilled off to obtain 4.02 g of 4-hydroxyphenyl-methyl-benzylsulfonium hexafluoroantimonate. (Yield 86%)

[Comparative Example 2]
Synthesis of 4-hydroxyphenyl-methyl-benzylsulfonium tetrakis (pentafluorophenyl) borate 2.97 g (0.01 mol) of 4-hydroxyphenyl-methyl-benzylsulfonium chloride was dispersed in 15 ml of dichloromethane, and equimolar tetrakis ( 30 g of an aqueous solution containing lithium pentafluorophenyl) borate was mixed at room temperature and stirred for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, then transferred to a rotary evaporator and the solvent was distilled off to obtain 7.46 g of 4-hydroxyphenyl-methyl-benzylsulfonium tetrakis (pentafluorophenyl) borate. It was. (Yield 82%)

[Comparative Example 3]
Synthesis of 4-hydroxyphenyl-methyl-benzylsulfonium hexafluorophosphate 30 g of aqueous solution containing 2.97 g (0.01 mol) of 4-hydroxyphenyl-methyl-benzylsulfonium chloride in 15 ml of dichloromethane and equimolar KPF ₆ Were mixed at room temperature and stirred as such for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, then transferred to a rotary evaporator, and the solvent was distilled off to obtain 3.31 g of 4-hydroxyphenyl-methyl-benzylsulfonium hexafluorophosphate. (Yield 88%)

[Comparative Example 4]
4-hydroxyphenyl dimethyl sulfonium hexafluoroantimonate synthesized 4-hydroxyphenyl dimethyl sulfonium chloride 1.92g of (0.01 mol) was dispersed in dichloromethane 15 ml, of an aqueous solution 30g including KSbF ₆ equimolar mixed at room temperature The mixture was stirred for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, and then transferred to a rotary evaporator, and the solvent was distilled off to obtain 3.56 g of 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate. (Yield 91%)

[Comparative Example 5]
Synthesis of 4-hydroxyphenyldimethylsulfonium tetrakis (pentafluorophenyl) borate 1.92 g (0.01 mol) of 4-hydroxyphenyldimethylsulfonium chloride is dispersed in 15 ml of dichloromethane and equimolar lithium tetrakis (pentafluorophenyl) borate 30 g of an aqueous solution containing was mixed at room temperature and stirred for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, and then transferred to a rotary evaporator and the solvent was distilled off to obtain 7.09 g of 4-hydroxyphenyldimethylsulfonium tetrakis (pentafluorophenyl) borate. (Yield 85%)

[Comparative Example 6]
Synthesis of 4-hydroxyphenyldimethylsulfonium hexafluorophosphate 1.92 g (0.01 mol) of 4-hydroxyphenyldimethylsulfonium chloride is dispersed in 15 ml of dichloromethane, and 30 g of an aqueous solution containing equimolar KPF ₆ is mixed at room temperature. The mixture was stirred for 3 hours. The dichloromethane layer was washed three times with water by a liquid separation operation, and then transferred to a rotary evaporator and the solvent was distilled off to obtain 2.79 g of 4-hydroxyphenyldimethylsulfonium hexafluorophosphate. (Yield 93%)

[Examples 6 to 10 and Comparative Examples 7 to 12]
The sulfonium salt (acid generator) of the present invention and the compound of the comparative example, each 1 part by weight, and 100 parts by weight of epoxide (bisphenol A type epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd., Epicoat 828) which is a cationically polymerizable compound The mixture was mixed to prepare a curable composition, and the gel time was measured according to the method of JISK5909.

As can be seen from the results in Table 1, the fluorinated alkyl phosphate sulfonium salt of the present invention is superior to the comparative sulfonium salt in curing performance of the cationic polymerization compound and has a toxic element such as Sb. Because there is no safety. Therefore, it turns out that it is useful as an acid generator.

The sulfonium salt of the present invention includes paints, coating agents, inks, inkjet inks, positive resists (formation of connection terminals and wiring patterns for manufacturing electronic components such as circuit boards, CSPs, MEMS elements, etc.), resist films, liquid resists, negatives Type resists (permanent film materials such as semiconductor device surface protection films, interlayer insulation films, planarization films, etc.), MEMS resists, photosensitive materials, various adhesives, molding materials, casting materials, putty, glass fiber impregnation It is preferably used as an acid generator used in an agent, a sealing material, a sealing material, a sealing material, an optical semiconductor (LED) sealing material, a nanoimprint material, a photofabrication material, a micro stereolithography material, and the like.

Claims (6)

The thermal acid generator which generate | occur | produces an acid by heating containing the fluorinated alkyl phosphate sulfonium salt shown by following formula (1).

[In formula (1), R ¹ and R ² each independently represents an alkyl group or an aralkyl group, and R ³ represents hydrogen, an alkyl group, a hydroxy group, a carboxyl group, an alkoxy group, an aryloxy group, an alkylcarbonyl group, an aryl group. Carbonyl group, aralkylcarbonyl group, alkoxycarbonyl group, aryloxycarbonyl group, aralkyloxycarbonyl group, alkylcarbonyloxy group, arylcarbonyloxy group, aralkylcarbonyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, aralkyloxycarbonyl Oxy group, arylthiocarbonyl group, arylthio group, alkylthio group, aryl group, heterocyclic hydrocarbon group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, aryl Represents a sulfonyl group, a hydroxy (poly) alkyleneoxy group, optionally substituted amino group, a cyano group, a nitro group or a halogen atom, m represents the number of R ^3, is an integer of 0 to 5. Rf represents an alkyl group in which 80% or more of hydrogen is substituted with a fluorine atom. b represents the number thereof and is an integer of 1 to 5. Rf may be the same or different. ] ^2. The thermal acid generation according to claim 1, wherein R ¹ is an alkyl group, R ² is an alkyl group or an aralkyl group, and R ³ is hydrogen, a hydroxy group, an acetoxy group, a methoxycarbonyloxy group, or a benzyloxycarbonyloxy group. Agent . The thermal acid generator according to claim 1 or 2, wherein m is 1. The sulfonium salt is phenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-hydroxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-acetoxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4 -Methoxycarbonyloxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-benzyloxycarbonyloxyphenyldimethylsulfonium tris (pentafluoroethyl) trifluorophosphate, phenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluoro Phosphate, 4-hydroxyphenyl-methyl-benzyl Rufonium tris (pentafluoroethyl) trifluorophosphate, 4-acetoxyphenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-methoxycarbonyloxyphenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate 4-benzyloxycarbonyloxyphenyl-methyl-benzylsulfonium tris (pentafluoroethyl) trifluorophosphate, phenyl-methyl-2-methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-hydroxyphenyl-methyl-2 -Methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-methoxyca Bonyloxyphenyl-methyl-2-methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-acetoxyphenyl-methyl-2-methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-benzyloxycarbonyloxyphenyl -Methyl-2-methylbenzylsulfonium tris (pentafluoroethyl) trifluorophosphate, phenyl-methyl-1-naphthylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate, 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium tris (Pentafluoroethyl) trifluorophosphate, 4-methoxycarbonyloxyphenyl-methyl-1-naphthylmethylsulfate Nitris (pentafluoroethyl) trifluorophosphate, 4-acetoxyphenyl-methyl-1-naphthylmethylsulfonium tris (pentafluoroethyl) trifluorophosphate and 4-benzyloxycarbonyloxyphenyl-methyl-1-naphthylmethylsulfonium tris ( The thermal acid generator according to claim 1 or 2, which is a kind selected from the group consisting of (pentafluoroethyl) trifluorophosphate. A curable composition comprising the thermal acid generator according to any one of claims 1 to 4 and a cationically polymerizable compound. A cured product obtained by curing the curable composition according to claim 5 .