JP4999044B2 - Sulfonium salt compound, cationic polymerization initiator and thermosetting composition - Google Patents

Description

  The present invention relates to a sulfonium salt compound, a cationic polymerization initiator and a thermosetting composition, and more particularly to a novel sulfonium salt compound, and a cationic polymerization initiator and a thermosetting composition using the same.

  The cationic polymerizable initiator has a function of receiving an energy such as heat and light to generate an acid and curing a cationic polymerizable compound such as an epoxy compound, and a sulfonium salt compound is used.

For example, in claim 1 of Patent Document 1, R ₁ S ⁺ R ₂ R ₃ X ⁻ (wherein R ₁ represents an alkyl group having a phenyl group or an ester group which may be substituted at the α-position of a sulfur atom; ₂ and R ₃ each represent an alkyl group which may have a substituent, and X represents SbF ₆ , AsF ₆ , PF ₆ or BF ₄ ). The sulfonium salt compound of Patent Document 1 has a feature of curing a cationic polymerizable compound in a short time. Further, claim 1 of Patent Document 2 discloses an aromatic sulfonium salt compound using a trifluoromethanesulfonate anion as a counter ion. Patent Document 2 describes that the sulfonium salt compound is improved in crystallinity by using a trifluoromethanesulfonate anion as a counter ion and has good stability to heat and light.
JP-A-7-126313 JP 2004-217551 A

  Like the sulfonium salt compound described in Patent Document 1, the cationic polymerization initiator is required to give a quicker curing by heating in order to shorten the curing process of the thermosetting composition containing the cationic polymerization initiator. ing. In addition, for printed circuit board interlayer insulation films, multilayer board insulation films, optical films, protective film applications for displays, etc., a high degree of flatness is required for the cured product after the thermosetting composition is cured. There is also a demand for a material that rapidly progresses until the formation of the resin and gives a curing behavior in which the time in the gel state having reflowability during the curing lasts to some extent. Furthermore, the cationic polymerization initiator is required to have good compatibility with the cationic polymerizable compound, no volatilization at the time of thermal curing, and no bleeding out from the cured product after curing.

  Accordingly, an object of the present invention is to provide a sulfonium salt compound suitable as a cationic polymerization initiator, capable of giving a thermosetting composition having a fast gelation to a cationic polymerizable thermosetting composition, and a cationic polymerization initiator using the same. The object is to provide a thermosetting composition.

  As a result of intensive studies to solve the above problems, the present inventors have found that when a sulfonium salt compound having a specific structure is used as a cationic polymerization initiator, the thermosetting composition has a fast gelation thermosetting behavior. As a result, the present invention has been completed.

（式中、Ａは炭素数１〜４のアルカンジイル基、Ｒは水素原子またはメチル基、Ｒ¹およびＲ²は、それぞれ独立に炭素数１〜８のアルキル基または下記一般式（２）、

（式中、Ａ¹は炭素数１〜４のアルカンジイル基、環Ｂはベンゼン環またはナフタレン環、Ｒ³は炭素数１〜４のアルキル基、ｎは０〜５の整数である）で表される基であり、Ｒ¹およびＲ²は、連結してテトラヒドロチオフェン環を形成してもよく、Ａｎ^y-は、ｙ価のアニオン、ｙは１または２である）で表されることを特徴とするものである。 The sulfonium salt compound of the present invention has the following general formula (1),

(In the formula, A is an alkanediyl group having 1 to 4 carbon atoms, R is a hydrogen atom or a methyl group, R ¹ and R ² are each independently an alkyl group having 1 to 8 carbon atoms, or the following general formula (2),

(Wherein A ¹ is an alkanediyl group having 1 to 4 carbon atoms, ring B is a benzene ring or naphthalene ring, R ³ is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 5). R ¹ and R ² may be linked to form a tetrahydrothiophene ring, An ^y− is a y-valent anion, and y is 1 or 2. It is a feature.

  The cationic polymerization initiator of the present invention is the above-described sulfonium salt compound of the present invention.

  Furthermore, the thermosetting composition of the present invention is characterized by containing the cationic polymerization initiator and the cationic polymerizable compound of the present invention.

  The sulfonium salt compound of the present invention functions as a cationic polymerization initiator that gives a cationically polymerizable thermosetting composition a fast gelling curing behavior.

で表され、カチオン重合開始剤として有用である。上記一般式（１）において、Ａは炭素数１〜４のアルカンジイル基であり、例えば、−ＣＨ₂−、−ＣＨ₂−ＣＨ₂−、−ＣＨ₂−ＣＨ₂−ＣＨ₂−、−ＣＨ（ＣＨ₃）−ＣＨ₂−、−ＣＨ₂−ＣＨ（ＣＨ₃）−、−Ｃ（ＣＨ₃）₂−、−ＣＨ₂−ＣＨ₂−ＣＨ₂−ＣＨ₂−、−ＣＨ（ＣＨ₃）−ＣＨ₂−ＣＨ₂−、−ＣＨ₂−ＣＨ（ＣＨ₃）−ＣＨ₂−、−ＣＨ₂−ＣＨ₂−ＣＨ（ＣＨ₃）−、−ＣＨ（ＣＨ₃）−ＣＨ（ＣＨ₃）−、−Ｃ（ＣＨ₃）₂−ＣＨ₂−、−ＣＨ₂−Ｃ（ＣＨ₃）₂−が挙げられる。 The sulfonium salt compound of the present invention has the following general formula (1),

And is useful as a cationic polymerization initiator. In the general formula (1), A is an alkanediyl group having 1 to 4 carbon atoms, _{e.g., -CH 2 -, - CH 2} -CH 2 -, - CH 2 -CH 2 -CH 2 -, - CH _{(CH 3) -CH 2 -,} - CH 2 -CH (CH 3) -, - C (CH 3) 2 -, - CH 2 -CH 2 -CH 2 -CH 2 -, - CH (CH 3) - _{CH 2 -CH 2 -, - CH} 2 -CH (CH 3) -CH 2 -, - CH 2 -CH 2 -CH (CH 3) -, - CH (CH 3) -CH (CH 3) -, - C (CH ₃ ) ₂ —CH ₂ —, —CH ₂ —C (CH ₃ ) ₂ — may be mentioned.

で表される基であり、Ｒ¹およびＲ²は、連結してテトラヒドロチオフェン環を形成してもよい。炭素数１〜８のアルキル基としては、メチル、エチル、プロピル、イソプロピル、ブチル、第２ブチル、第３ブチル、イソブチル、アミル、イソアミル、第３アミル、ヘキシル、２−ヘキシル、３−ヘキシル、シクロヘキシル、１−メチルシクロヘキシル、ヘプチル、２−ヘプチル、３−ヘプチル、イソヘプチル、第３ヘプチル、ｎ−オクチル、イソオクチル、第３オクチル、２−エチルヘキシル等が挙げられる。 In the general formula (1), R is a hydrogen atom or a methyl group, and R ¹ and R ² are each independently an alkyl group having 1 to 8 carbon atoms or the following general formula (2),

R ¹ and R ² may be linked to form a tetrahydrothiophene ring. Examples of the alkyl group having 1 to 8 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, secondary butyl, tertiary butyl, isobutyl, amyl, isoamyl, tertiary amyl, hexyl, 2-hexyl, 3-hexyl, and cyclohexyl. 1-methylcyclohexyl, heptyl, 2-heptyl, 3-heptyl, isoheptyl, tertiary heptyl, n-octyl, isooctyl, tertiary octyl, 2-ethylhexyl and the like.

In the general formula (2), A ¹ represents alkanediyl group having 1 to 4 carbon atoms include the same groups as those exemplified in the above A. Ring B is a benzene ring or naphthalene ring, R ³ is an alkyl group having 1 to 4 carbon atoms, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, secondary butyl, tertiary butyl, and isobutyl. n is an integer of 0-5.

In the general formula (1), those in which an aromatic ring is directly bonded to S ⁺ are slow to cure and have poor light stability when used as a cationic initiator by thermal curing. Moreover, since compatibility with a cationically polymerizable compound may deteriorate, it is not preferable.

In the sulfonium salt compound represented by the general formula (1) of the present invention, A is ethylene, and R ¹ and R ² are each independently methyl, benzyl or 4-methylphenylmethyl, or R ¹ and A group in which R ² is linked to form a tetrahydrothiophene ring is preferable because it can be obtained at low cost and in a high yield without impairing the function of the present invention.

Specific examples of the cation component of the sulfonium salt compound of the present invention include the following cation Nos. 1-32.

In the general formula representing the sulfonium salt compound of the present invention (1), anions represented by An ^y- represents a monovalent or divalent anion. Monovalent halogen anions such as chlorine anion, bromine anion, iodine anion, fluorine anion; perchlorate anion, chlorate anion, thiocyanate anion, phosphorus hexafluoride anion, antimony hexafluoride anion, tetrafluoride Inorganic anions such as boron anion; trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, nonafluorobutanesulfonate anion, undecafluoropentanesulfonate anion, tridecafluorohexanesulfonate anion , Pentadecafluoroheptanesulfonate anion, heptadecafluorooctanesulfonate anion, p-toluenesulfonate anion, benzenesulfonate anion, dodecylbenzenesulfone Acid anion, naphthalenesulfonate anion, anthracenesulfonate anion, acenaphthenesulfonate anion, phenanthrenesulfonate anion, camphorsulfonate anion, methanesulfonate anion, ethanesulfonate anion, propanesulfonate anion, butanesulfonate anion, pentane Sulfonate anion, hexane sulfonate anion, heptane sulfonate anion, octane sulfonate anion, norbornene sulfonate anion, adamantane sulfonate anion, cyclohexane sulfonate anion, diphenylamine-4-sulfonate anion, 2-amino-4-methyl- Organic sulfonate anions such as 5-chlorobenzenesulfonate anion and 2-amino-5-nitrobenzenesulfonate anion Bis (benzenesulfone) imide anion, bis (toluenesulfone) imide anion, bis (methanesulfone) imide anion, bis (trifluoromethanesulfone) imide anion, bis (pentafluoroethanesulfone) imide anion, bis (heptafluoropropanesulfone) Organic sulfonimide anions such as imide anion, bis (nonafluorobutanesulfone) imide anion, (trifluoromethanesulfone) (nonafluorobutanesulfone) imide anion, (methanesulfone) (trifluoromethanesulfone) imide anion; octyl phosphate anion, Dodecyl phosphate anion, octadecyl phosphate anion, phenyl phosphate anion, nonylphenyl phosphate anion, 2,2′-methylenebis (4,6-ditertiary butyrate Organophosphate anions such as phenyl) phosphonic acid anion; Organoboronic anions such as tetrakis (pentafluorophenyl) boron anion are mentioned. Examples of divalent ones include benzenedisulfonic acid anion, naphthalenedisulfonic acid anion, etc. Is mentioned.

The anion represented by Any ^y- is appropriately selected depending on the curing behavior of cationic polymerization. For example, if it is simply desired to shorten the time until curing, inorganic anions such as phosphorus hexafluoride anion, boron tetrafluoride anion, and antimony hexafluoride anion are suitable. In addition, when a high degree of flatness is required for the cured product after thermosetting, or when a flat film is formed by embedding irregularities in a substrate having irregularities, it is necessary to improve the reflow property. In order to improve the reflow property, a material that gives a curing behavior such that the gel state during curing continues to some extent is suitable. Examples of the anion that gives such properties include an organic sulfonate anion, an organic sulfonimide anion, and an organic boron anion. Specifically, a camphor sulfonate anion, a trifluoromethane sulfonate anion, and a nonafluorobutane sulfonate anion. Bis (trifluoromethanesulfone) imide anion and tetrakis (pentafluorophenyl) boron anion.

In the sulfonium salt compound of the present invention, the production method is not particularly limited, and a method applying a well-known organic synthesis reaction can be used. For example, HO-AS ⁺ R ¹ R ² .1 / yAn ^y- obtained from a salt compound for introducing a thioether compound, a halogenated organic compound and an anionic component 1 / yAn ^y- as an intermediate is used as an intermediate. This intermediate can be obtained by reaction of a (meth) acrylic acid derivative.

Specific examples of the method for obtaining the above intermediate, a compound represented by ^{HO-A-S-R 1} , a compound represented by ^{Cl-R 2, M + 1} / yAn y- (M is an alkali metal ), A compound represented by R ¹ SR ² , a compound represented by HO-A-Cl, and a compound represented by M ⁺ 1 / yAn ^y- The method of letting it be mentioned. Examples of the (meth) acrylic acid derivatives include organic acids such as acrylic acid and methacrylic acid; acid halides such as acrylic acid chloride and methacrylic acid chloride; methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. And lower esters. The sulfonium salt compound of the present invention can be obtained by applying a known esterification reaction or transesterification reaction using these intermediates and acrylic acid derivatives.

  Since the sulfonium salt compound of the present invention has a polymerizable carbon double bond derived from acrylic acid or methacrylic acid, a compound having a double bond such as (meth) acrylate, vinyl ether or styrene is used as the cationic polymerizable compound. In addition, it is expected that the cationic polymerization initiator can be prevented from bleeding out because it is excellent in compatibility with the polymer and is incorporated into the polymer as a cured product by chemical bonding after curing.

  The sulfonium salt compound of the present invention can also be used as a raw material for a polymer such as a functional oligomer or a functional polymer using itself as a polymerizable monomer. Examples of the polymer include those composed only of the sulfonium salt compound of the present invention, and copolymers with other polymerizable monomers, and these can be obtained by polymerization by light or heat.

  The cationic polymerization initiator of the present invention is characterized in that it is the sulfonium salt compound of the present invention, and the thermosetting composition of the present invention comprises the cationic polymerization initiator of the present invention and a cationic polymerizable compound. A composition containing a compound as a curable component and cured by thermal energy. In addition to the cationic polymerization initiator and the cationic polymerizable compound, which are essential components, an optional component such as a solvent or dispersion medium, a polymerizable compound other than the cationic polymerizable compound, and various additives may be contained.

  Examples of the cationic polymerizable compound that is an essential component of the thermosetting composition of the present invention include epoxy compounds, phenol compounds, aldehyde compounds, vinyl ether compounds, styrene compounds, cyclic ether compounds, lactone compounds, episulfide compounds, silicones, and the like. Examples of the compound include one or a mixture of two or more so as to obtain a cured product by cationic polymerization.

  Various organic solvents can be used as the solvent or dispersion medium, which is an optional component in the thermosetting composition of the present invention. Examples of the organic solvent include alcohol solvents, polyol solvents, ketone solvents, ester solvents, ether solvents, polyether solvents, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, chlorine solvents. , A hydrocarbon solvent having a cyano group, a pyrrolidone solvent, and the like. These may be used alone or in combination of two or more.

  Examples of the polymerizable compound other than the cationic polymerizable compound which is an optional component in the thermosetting composition of the present invention include radical polymerizable compounds represented by acrylate compounds, methacrylate compounds, and olefin compounds.

  In addition, various additives that are optional components in the thermosetting composition of the present invention include benzotriazole-based, triazine-based, and benzoate-based ultraviolet absorbers; phenol-based, phosphorus-based, sulfur-based antioxidants; cationic interfaces. Antistatic agent comprising activator, anionic surfactant, nonionic surfactant, amphoteric surfactant, etc .; halogen compound, phosphate ester compound, phosphate amide compound, melamine compound, fluororesin or metal Flame retardants such as oxides, (poly) phosphate melamine, (poly) phosphate piperazine; hydrocarbons, fatty acids, aliphatic alcohols, aliphatic esters, aliphatic amides or metal soaps; dyes , Pigments, colorants such as carbon black; fumed silica, fine particle silica, silica, diatomaceous earth, clay, kaolin, diatomaceous earth, Silica-based inorganic additives such as licagel, calcium silicate, sericite, kaolinite, flint, feldspar powder, aragonite, attapulgite, talc, mica, minnesotite, pyrophyllite, silica and the like; fillers such as glass fiber and calcium carbonate; Examples include nucleating agents, crystallization agents such as crystallization accelerators, silane coupling agents, and the like.

  When the amount of the cationic polymerization initiator used in the thermosetting composition of the present invention is less than 0.01 parts by mass relative to 100 parts by mass of the cationic polymerizable compound, curing may be insufficient. In addition to not being able to obtain an increase in the effect of use even if the amount exceeds 1, it may have an adverse effect on the physical properties of the cured product. More preferred. In addition, the amount of the solvent or dispersion medium, polymerizable compound other than the cationic polymerizable compound, and optional components such as various additives with respect to 100 parts by mass of the cationic polymerizable compound is generally 0 to 10,000 parts by mass of the solvent or dispersion medium. The polymerizable compound other than the cationic polymerizable compound is 0 to 100 parts by mass, and the various additives are 0 to 10 parts by mass in each component, and the total is 0 to 100 parts by mass.

  Applications of the thermosetting composition of the present invention include ink, protective film (protective layer), paint, adhesive, insulating material, structural material, optical film, FRP, resist and the like. In particular, it is useful as an optical film, specifically as an optical film for liquid crystal or plasma display, and more specifically as a color filter protective film for plasma display, antireflection film, light diffusion film, film sealant, film adhesive, polarizing plate protection It is useful as a film, an antistatic film, a hard coat film, and an optical waveguide clad.

EXAMPLES Hereinafter, although an Example, a comparative example, etc. demonstrate this invention further in detail, this invention is not limited to these.
Synthesis example 1
Cation No. Production of 16 trifluoromethanesulfonate (synthesis of intermediate 1)
A 500 ml reaction flask was charged with 0.54 mol of 2- (methylthio) ethanol, 0.54 mol of 1-chloromethyl-4-methylbenzene, 100 g of methanol, and 0.60 mol of lithium trifluoromethanesulfonate, and the mixture was heated at 25 ° C. for 24 hours. Stir. Next, methanol was removed under reduced pressure, and 100 g of methylene chloride was added to the resulting residue. This was washed with 100 g of water three times, and then the methylene chloride was removed under reduced pressure to obtain an intermediate as white crystals in a yield of 73%. It was.

(Synthesis of target product)
A 1-liter reaction flask was charged with 0.29 mol of Intermediate 1 obtained by the above operation, 0.44 mol of potassium carbonate, and 300 g of acetone, and cooled to 5 ° C. with stirring. To this, 0.30 mol of methacrylic acid chloride was added dropwise so that the reaction system did not exceed 5 ° C, and after the addition, the reaction was carried out at 5 ° C for 3 hours. 300 g of water was added to the resulting reaction system, then acetone was removed under reduced pressure, and 200 g of methylene chloride was added and stirred. The aqueous phase was discarded, and the resulting methylene chloride solution was washed with 300 g of water three times and then concentrated under reduced pressure to obtain the desired product as a colorless liquid in a yield of 62%. The obtained colorless liquid was analyzed by ¹ H-NMR, ¹⁹ F-NMR (400 MHz, deuterated chloroform solvent), and MALDI TOFMASS to confirm that it was the target product.

(result of analysis)
・¹ H-NMR (chemical shift; H number; peak)
(7.21-7.35; 4; d) (6.12-5.68; 2; d) (4.78-4.87; 2; d) (4.42-3.84; 4; m) (2.91; 3; s) (2.35; 3; s) (1.92: 3; s)
¹⁹ F-NMR (chemical shift; F number; peak)
(75.6; 3; s)
・ MALDI TOFASS
Cation mass: 266.0 (theoretical value 265.4)
Anion mass: 150.0 (theoretical 149.1)

Synthesis example 2
Cation No. Production of 16 antimony hexafluoride salt The target compound was obtained in a yield of 51% in the same manner as in Synthesis Example 1, except that lithium trifluoromethanesulfonate was changed to potassium antimony hexafluoride. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis example 3
Cation No. Production of 16 hexafluorophosphorus salt The same procedure as in Synthesis Example 1 was carried out except that lithium trifluoromethanesulfonate was changed to potassium hexafluorophosphate, and the yield was 53%. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis example 4
Cation No. Production of 16 camphor sulfonate The same operation as in Synthesis Example 1 was carried out except that lithium trifluoromethanesulfonate was changed to lithium camphorsulfonate, and the yield was obtained in 36%. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis example 5
Cation No. Production of 16 nonafluorobutane sulfonate The same procedure as in Synthesis Example 1 was repeated except that the lithium trifluoromethanesulfonate was changed to lithium nonafluorobutanesulfonate to obtain 60% yield. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis Example 6
Cation No. Production of 16 tetrakis (pentafluorophenyl) boron salt The same procedure as in Synthesis Example 1 was carried out except that the lithium trifluoromethanesulfonate was changed to lithium tetrakis (pentafluorophenyl) boron to obtain a yield of 52%. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis example 7
Cation No. Production of 20 trifluoromethanesulfonate salt The same procedure as in Synthesis Example 1 was carried out except that 2- (methylthio) ethanol was changed to 2- (4-methylphenylmethylthio) ethanol, and the yield was 57%. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis Example 8
Cation No. Production of 15 trifluoromethanesulfonate salt The same procedure as in Synthesis Example 1 was carried out except that 1-chloromethyl-4-methylbenzene was changed to chloromethylbenzene, and a yield of 56% was obtained. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis Example 9
Cation No. Production of 14 trifluoromethanesulfonate (synthesis of intermediate 2)
A 500 ml reaction flask was charged with 0.54 mol of tetrahydrothiophene, 0.54 mol of 2-chloroethanol, 100 g of methanol, and 0.60 mol of lithium trifluoromethanesulfonate, and stirred at 25 ° C. for 24 hours. Next, methanol was removed under reduced pressure, and 100 g of methylene chloride was added to the resulting residue. The methylene chloride composition was washed with 100 g of water three times, and then the methylene chloride was removed under reduced pressure to obtain Intermediate 2 in a yield of 58%.

(Synthesis of target product)
The same operation as in Synthesis Example 1 was performed except that Intermediate 1 was changed to Intermediate 2 obtained by the above operation, and the target product was obtained as crystals from Intermediate 2 in a yield of 51%. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis Example 10
Cation No. 6 Preparation of trifluoromethanesulfonate The same operation as in Synthesis Example 1 was carried out except that methacrylic acid chloride was changed to acrylic acid chloride to obtain the target compound as crystals in a yield of 37%. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Synthesis Example 11
Cation No. 6 Preparation of bis (trifluoromethanesulfone) imide salt The same procedure as in Synthesis Example 1 was conducted except that methacrylic acid chloride was changed to acrylic acid chloride and lithium trifluoromethanesulfonate was changed to bis (trifluorosulfone) imide potassium. The target compound was obtained in a yield of 38%. This was analyzed in the same manner as in Synthesis Example 1 and confirmed to be the target product.

Examples 1 to 11 and Comparative Examples 1 and 2
1 part by mass of each of the sulfonium salt compounds described in Table 1 below as a cationic polymerization initiator was added to 100 parts by mass of a bisphenol A type epoxy resin (Adeka Resin EP-4100; manufactured by Asahi Denka Kogyo Co., Ltd.). A thermosetting composition was obtained. In addition, 100 parts by mass of bisphenol A type epoxy resin (Adeka Resin EP-4100; manufactured by Asahi Denka Kogyo Co., Ltd.) was added 1 part by mass of the sulfonium salt compound (Comparative Compounds 1 and 2) shown below as a cationic polymerization initiator. Comparative thermosetting compositions 1 and 2 were obtained.

(Evaluation of gelation time)
The gelation time (tg) was measured for the obtained thermosetting composition. The test method was a method in which 0.5 g of the thermosetting composition was weighed in an aluminum pan having a diameter of 3 cm and heated on a hot plate heated to 200 ° C. The time until the viscosity of the specimen started to increase by visual inspection and palpation with a spatula was defined as the gelation time (tg). The obtained results are also shown in Table 1 below.

  From Table 1 above, the thermosetting composition using the sulfonium salt compound of the present invention as a cationic polymerization initiator has a short time to gelation (tg). On the other hand, it was confirmed that the comparative thermosetting composition took a long time to gelation.

Claims (5)

The following general formula (1),

(In the formula, A is an alkanediyl group having 1 to 4 carbon atoms, R is a hydrogen atom or a methyl group, R ¹ and R ² are each independently an alkyl group having 1 to 8 carbon atoms, or the following general formula (2),

(Wherein A ¹ is an alkanediyl group having 1 to 4 carbon atoms, ring B is a benzene ring or naphthalene ring, R ³ is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 5). R ¹ and R ² may be linked to form a tetrahydrothiophene ring, and An ^y- is a phosphorus hexafluoride anion, boron tetrafluoride anion, antimony hexafluoride anion, camphor An anion selected from the group consisting of sulfonate anion, trifluoromethanesulfonate anion, nonafluorobutanesulfonate anion, bis (trifluoromethanesulfone) imide anion and tetrakis (pentafluorophenyl) boron anion, y is 1 or 2 A sulfonium salt compound represented by the formula:   The sulfonium salt compound according to claim 1, wherein A is an ethylene group. The sulfonium salt compound according to claim 1 or 2, wherein R ¹ and R ² are each independently methyl, benzyl or 4-methylphenylmethyl, or R ¹ and R ² are linked to form a tetrahydrothiophene ring. A cationic polymerization initiator, which is the sulfonium salt compound according to any one of claims 1 to 3 . A thermosetting composition comprising the cationic polymerization initiator according to claim 4 and a cationic polymerizable compound.