JP2005035953A - Photopolymerization initiator and photocurable composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photopolymerization initiator having a fast curing rate and a photocurable composition containing the photopolymerization initiator. <P>SOLUTION: The present invention relates to an aromatic sulfonium salt represented by general formula (1) (wherein R<SP>1</SP>to R<SP>19</SP>are each independently a hydrogen atom, a halogen atom or a 1-10C alkyl group; X<SP>-</SP>is an inorganic acid ion or an organic acid ion; n is an integer of 2-5), the photopolymerization initiator comprising the aromatic sulfonium salt and the photocurable composition containing the photopolymerization initiator. An aromatic sulfonium salt represented by general formula (1) wherein R<SP>3</SP>and R<SP>8</SP>are the same and R<SP>3</SP>and R<SP>8</SP>are each a halogen atom or a 1-10C alkyl group and R<SP>1</SP>, R<SP>2</SP>, R<SP>4</SP>to R<SP>7</SP>and R<SP>9</SP>to R<SP>19</SP>are each a hydrogen atom is preferably used as the aromatic sulfonium salt. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an aromatic sulfonium salt which is a novel compound, a photopolymerization initiator comprising the aromatic sulfonium salt, and a photocurable composition containing the photopolymerization initiator.

  Since the photocurable composition is easy to handle, it is widely used as a printing plate making material, various resists, and an ultraviolet curable coating.

  Conventionally, as a photocurable composition, a photopolymerization monomer and / or a photopolymerizable polymer and an aryldiazonium salt composition (Patent Document 1), a photocuring agent to which a photopolymerization initiator such as a triarylsulfonium complex salt is added. The composition (patent document 2) etc. are known.

  However, the aryldiazonium salt has a problem that a coating film obtained by curing foams because nitrogen gas is released simultaneously with Lewis acid by photolysis. In addition, a photopolymerization initiator such as a triarylsulfonium complex salt has a problem that its curing rate is slower than that of an aryldiazonium salt. Therefore, there is a need for a novel photopolymerization initiator that increases the curing rate.

US Pat. No. 3,205,157 US Pat. No. 4,231,951

  The objective of this invention is providing the photoinitiator with a quick cure rate, and a photocurable composition containing the same.

  The present invention provides the following general formula (1);

（式中、Ｒ^１〜Ｒ^１９は、それぞれ独立して、水素原子、ハロゲン原子または炭素数１〜１０のアルキル基を、Ｘ⁻は無機酸イオンまたは有機酸イオンを示す。ｎは２〜５の整数を示す。）

(In the formula, R ^{1 to} R ¹⁹ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms, X ⁻ represents an inorganic acid ion or an organic acid ion, and n represents 2 to 5). Indicates an integer.)

And a photopolymerization initiator comprising the aromatic sulfonium salt and a photocurable composition containing the photopolymerization initiator.

  The aromatic sulfonium salt of the present invention can provide a photopolymerization initiator having a high curing rate and a photocurable composition containing the photopolymerization initiator.

The aromatic sulfonium salt of the present invention is a compound represented by the general formula (1). In the general formula (1), R ^{1 to} R ¹⁹ each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms, and X ⁻ represents an inorganic acid ion or an organic acid ion. n shows the integer of 2-5.

  As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example.

  Examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n- An octyl group, n-decyl group, etc. are mentioned.

  Examples of inorganic acid ions include hexafluoroantimonate ions, hexafluoroarsenate ions, hexafluorophosphate ions, pentafluorohydroxyantimonate ions, tetrafluoroborate ions, tetrakis (pentafluorophenyl) borate ions, tetrakis. (Trifluoromethylphenyl) borate ion, trifluoro (pentafluorophenyl) borate ion, tetrakis (difluorophenyl) borate ion, difluorobis (pentafluorophenyl) borate ion and the like.

  Examples of organic acid ions include methanesulfonic acid ions, propanesulfonic acid ions, butanesulfonic acid ions, octanesulfonic acid ions, trifluoromethanesulfonic acid ions, benzenesulfonic acid ions, benzene-1,3-disulfonic acid ions, p -Toluenesulfonic acid ion, anthraquinone-1-sulfonic acid ion, anthraquinone-2-sulfonic acid ion, anthraquinone-1,5-disulfonic acid ion and the like.

  Specific examples of the aromatic sulfonium salt of the present invention include diphenyl-4- (phenyldithio) phenylsulfonium hexafluorophosphate, diphenyl-4- (phenyldithio) phenylsulfonium hexafluoroantimonate, diphenyl-4- (phenyldithio). ) Phenylsulfonium trifluoromethanesulfonate, bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluorophosphate, bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate, Bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium trifluoromethanesulfonate, bis (4-fluorophenyl) -4- (phenyldithio) phenylsulfonate Hexafluorophosphate, bis (4-fluorophenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate, bis (4-fluorophenyl) -4- (phenyldithio) phenylsulfonium trifluoromethanesulfonate, diphenyl- 4- (phenyltrithio) phenylsulfonium hexafluorophosphate, diphenyl-4- (phenyltrithio) phenylsulfonium hexafluoroantimonate, diphenyl-4- (phenyltrithio) phenylsulfonium trifluoromethanesulfonate, diphenyl-4- (Phenyltetrathio) phenylsulfonium hexafluorophosphate, diphenyl-4- (phenyltetrathio) phenylsulfonium hexafluoroantimonate , Diphenyl-4- (phenyl penta) phenyl sulfonium hexafluorophosphate, diphenyl-4- (phenyl penta) phenyl sulfonium hexafluoroantimonate and the like.

Among these, from the viewpoint of obtaining a photopolymerization initiator having a faster curing rate, in the general formula (1), R ³ and R ⁸ are a halogen atom or an alkyl group having 1 to 10 carbon atoms, and R ¹ and R ² , R ^{4 to} R ⁷ and R ^{9 to} R ¹⁹ are preferably hydrogen atoms, particularly bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluorophosphate, bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate, bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium trifluoromethanesulfonate, bis (4-fluorophenyl) -4- (phenyldithio) phenyl Sulfonium hexafluorophosphate, bis (4-fluorophenyl) More preferred are -4- (phenyldithio) phenylsulfonium hexafluoroantimonate and bis (4-fluorophenyl) -4- (phenyldithio) phenylsulfonium trifluoromethanesulfonate.

  As the method for producing the aromatic sulfonium salt of the present invention, for example, a diphenyl polysulfide represented by the following general formula (2) and a substituted or unsubstituted diphenyl sulfoxide are condensed in an acid solvent using a condensing agent. Then, the reaction solution can be neutralized and reacted with an alkali metal salt of a desired inorganic acid or organic acid.

In the general formula (2), R ^{11 to} R ¹⁹ represent the same groups as R ^{11 to} R ^{19 in} the general formula (1). n shows the integer of 2-5.

  Specific examples of diphenyl polysulfides include diphenyl disulfide, 4- (methylphenyl) phenyl disulfide, 4- (ethylphenyl) phenyl disulfide, 4- (fluorophenyl) phenyl disulfide, 4- (chlorophenyl) phenyl disulfide, 4- ( Bromophenyl) phenyl disulfide, diphenyl trisulfide, 4- (methylphenyl) phenyl trisulfide, 4- (ethylphenyl) phenyl trisulfide, diphenyltetrasulfide, 4- (methylphenyl) phenyl tetrasulfide, diphenylpentasulfide, 4- (Methylphenyl) phenyl pentasulfide and the like.

  Specific examples of diphenyl sulfoxides include diphenyl sulfoxide, bis (4-methylphenyl) sulfoxide, bis (4-ethylphenyl) sulfoxide, bis (4-n-propylphenyl) sulfoxide, bis (4-isopropylphenyl) sulfoxide, Bis (4-n-butylphenyl) sulfoxide, bis (4-isobutylphenyl) sulfoxide, bis (4-tert-butylphenyl) sulfoxide, bis (4-fluorophenyl) sulfoxide, bis (4-chlorophenyl) sulfoxide, bis ( 4-bromophenyl) sulfoxide and the like.

  The amount of diphenyl sulfoxide to be used is 1 to 5 mol, preferably 1 to 3 mol with respect to 1 mol of diphenyl polysulfide. If the amount of diphenyl sulfoxide used is less than 1 mol, the yield may be reduced. Moreover, when the usage-amount of diphenyl sulfoxide exceeds 5 mol, there is no effect corresponding to a usage-amount and it is not economical.

  Specific examples of the acid solvent include methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid and the like.

  The amount of the acid solvent to be used is 5 to 50 mol, preferably 5 to 10 mol, per 1 mol of diphenyl sulfoxide. When the usage-amount of an acid solvent is less than 5 mol, there exists a possibility that a yield may fall. Moreover, when the usage-amount of an acid solvent exceeds 50 mol, there is no effect commensurate with the usage-amount and volume efficiency deteriorates and it is not economical.

  Specific examples of the condensing agent include concentrated sulfuric acid, acetic anhydride, polyphosphoric acid, diphosphorus pentoxide and the like.

  The amount of the condensing agent used is 1 to 10 mol, preferably 1 to 3 mol, per 1 mol of diphenyl sulfoxides. When the amount of the condensing agent used is less than 1 mol, the yield may decrease. Moreover, when the usage-amount of a condensing agent exceeds 10 mol, there is no effect corresponding to a usage-amount and it is not economical.

  The reaction temperature is 10 to 80 ° C, preferably 20 to 50 ° C. When reaction temperature is lower than 10 degreeC, reaction rate becomes slow and there exists a possibility that reaction may require a long time. Moreover, when reaction temperature is higher than 80 degreeC, a side reaction tends to occur and there exists a possibility that a yield and purity may fall. While the reaction time varies depending on the reaction temperature, it is generally 1 to 24 hours, preferably 2 to 5 hours.

  Specific examples of alkali metal salts of inorganic acids include sodium hexafluoroantimonate, potassium hexafluoroantimonate, sodium hexafluoroarsenate, potassium hexafluoroarsenate, sodium hexafluorophosphate, potassium hexafluorophosphate, pentafluoro Sodium hydroxoantimonate, potassium pentafluorohydroxoantimonate, sodium tetrafluoroborate, potassium tetrafluoroborate, sodium tetrakis (pentafluorophenyl) borate, tetrakis (pentafluorophenyl) potassium borate, tetrakis (trifluoromethylphenyl) ) Sodium borate, potassium tetrakis (trifluoromethylphenyl) borate, sodium trifluoro (pentafluorophenyl) borate , Potassium trifluoro (pentafluorophenyl) borate, sodium tetrakis (difluorophenyl) borate, potassium tetrakis (difluorophenyl) borate, sodium difluorobis (pentafluorophenyl) borate, difluorobis (pentafluorophenyl) boric acid Potassium etc. are mentioned.

  Examples of alkali metal salts of organic acids include sodium methanesulfonate, sodium ethanesulfonate, sodium propanesulfonate, sodium butanesulfonate, sodium octanesulfonate, sodium trifluoromethanesulfonate, sodium benzenesulfonate, and benzene-1. , 3-disulfonic acid sodium salt, p-toluenesulfonic acid sodium salt, anthraquinone-1-sulfonic acid sodium salt, anthraquinone-2-sulfonic acid sodium salt, anthraquinone-1,5-disulfonic acid sodium salt, methanecarboxylic acid sodium salt, ethanecarboxylic acid sodium salt, Sodium propanecarboxylate, sodium butanecarboxylate, sodium octanecarboxylate, sodium trifluoromethanecarboxylate, sodium benzenecarboxylate Helium, it may be mentioned p- toluenesulfonic sodium carboxylate and the like. Of these alkali metal salts of inorganic or organic acids, potassium hexafluoroantimonate is preferred from the viewpoint of faster curing rate of the photopolymerization initiator and economy, and hexafluorophosphorus from the viewpoint of safety. Potassium acid is preferred.

  The amount of the alkali metal salt of the inorganic acid or organic acid used is 1 to 5 mol, preferably 1 to 3 mol per 1 mol of diphenyl sulfoxides. When the amount of the alkali metal salt of the inorganic acid or organic acid is less than 1 mol, the yield may be reduced. Moreover, when the usage-amount of the alkali metal salt of an inorganic acid or an organic acid exceeds 5 mol, there is no effect corresponding to a usage-amount and it is not economical. In addition, the alkali metal salt of an inorganic acid or an organic acid is usually used as an aqueous solution, and the concentration is 1 to 80% by weight, preferably 5 to 10% by weight.

  The reaction temperature for reacting the alkali metal salt of an inorganic acid or organic acid with the reaction product after the condensation reaction is 10 to 80 ° C., preferably 20 to 50 ° C. When reaction temperature is lower than 10 degreeC, reaction rate becomes slow and there exists a possibility that reaction may require a long time. Moreover, when reaction temperature is higher than 80 degreeC, a side reaction tends to occur and there exists a possibility that a yield and purity may fall.

  The present invention includes reacting an alkali metal salt of an inorganic acid or an organic acid with a reaction product after the condensation reaction for about 1 hour, adding and extracting an organic solvent such as dichloromethane, and concentrating the organic solvent to purify the column. The aromatic sulfonium salt can be obtained.

  The photopolymerization initiator of the present invention comprises an aromatic sulfonium salt represented by the general formula (1). In addition, you may use the said aromatic sulfonium salt individually or in mixture of 2 or more types.

  The photocurable composition of the present invention contains a photopolymerizable monomer and / or photopolymerizable polymer and the photopolymerization initiator.

  Examples of the photopolymerizable monomer include monofunctional glycidyl ether compounds such as allyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, and 2-methyloctyl glycidyl ether; 1,6-hexanediol glycidyl ether Polyfunctional glycidyl ether compounds such as trimethylolpropane triglycidyl ether, ethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether; glycidyl ester compounds such as glycidyl (meth) acrylate, diglycidyl diphthalate and diglycidyl tetrahydrophthalate; bisphenol A Bisphenol F, brominated bisphenol A, biphenol, resorcin, etc. 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylethyl-3,4-epoxycyclohexanecarboxylate, allylcyclohexene dioxide-3,4-epoxy-4 -Cycloaliphatic epoxy compounds such as methylcyclohexyl-2-propylene oxide and bis (3,4-epoxycyclohexyl) ether; hydroxyalkyl (meta) such as 2-hydroxyethyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate ) Acrylates; vinyl acetate, acrylonitrile, methacrylonitrile, vinylidene chloride, vinyl chloride, styrene, sodium styrene sulfonate, 2-methylstyrene, vinyltoluene, tert-butylstyrene , Vinyl compounds such as chlorostyrene, vinyl anisole, vinyl naphthalene, ethylene, propylene, isopropylene, butadiene, chloroprene, vinyl ether, vinyl ketone, N-vinyl pyrrolidone; tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthylene diisocyanate, lysine Isocyanate compounds such as diisocyanate methyl ester, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, hexamethylene diisocyanate, 4,4-bis (isocyanatocyclohexyl) methane, isophorone diisocyanate; trimethylene oxide, 3,3-dimethyloxetane, 3,3 -Dichloromethyloxetane, 3-ethyl-3-phenoxymethyloxe Tan, tri [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, bis [(3-ethyl-3-oxetanylmethoxy) methylphenyl] ether, (3-ethyl-3-oxetanylmethoxy) oligodimethylsiloxane, spiro [Bicyclo [2.2.2] octane-2,3′-oxetane], Spiro [7-oxabicyclo [2.2.1] heptane-2,3′-oxetane], 5-methyl-2-oxaspiro [ 3.5] oxetane compounds such as nonane and spiro [3-methylbicyclo [2.2.1] heptane-2,3′-oxetane]; 2,3-epithiopropylthiobenzene, 2,3-epithiopropyl Thiobutane, 2,3-epithiopropylthiohexane, 2,3-epithiopropylthiobenzene, 2,3-epithiopropyloxy , 2,3-epithiopropyloxybutane, 2,3-epithiopropyloxyhexane, 2,3-epithiopropyl (meth) acrylate, bis [4- (2,3-epithiopropylthio) phenyl] And episulfide compounds such as sulfide, bis [4- (2,3-epithiopropylthio) phenyl] ether, bis [4- (2,3-epithiopropylthio) phenyl] methane, and the like.

  Examples of the photopolymerizable polymer include compounds obtained by glycidyl etherification of bisphenol novolac resin, phenol novolac resin, cresol novolac resin, and the like.

  Among these, an epoxy compound or an oxetane compound is desirable in order to take advantage of the high curing rate of the photopolymerization initiator. These photopolymerizable monomers and / or photopolymerizable polymers may be used alone or in combination of two or more. In addition, (meth) acryl in this specification shows an acryl or a methacryl.

  The amount of the photopolymerization initiator used is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total amount of the photopolymerizable monomer and / or photopolymerizable polymer. desirable. When the usage-amount of a photoinitiator is less than 0.01 weight part, there exists a possibility that photocuring may become inadequate. Moreover, when the usage-amount of a photoinitiator exceeds 10 weight part, there exists a possibility that the hardened | cured material obtained by photocuring may become a low molecular weight hardened | cured material.

  The photocurable composition of the present invention can be produced, for example, by stirring and mixing a photopolymerizable monomer and / or photopolymerizable polymer and a photopolymerization initiator.

  Although the temperature at the time of stirring and mixing is not specifically limited, Usually, 0-100 degreeC, Preferably it is desirable that it is 20-50 degreeC. The stirring time is 0.1 to 12 hours, preferably 0.1 to 6 hours.

  Moreover, the photocurable composition of this invention may mix an organic solvent as needed. Specific examples of the organic solvent include ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, propylene carbonate, isopropyl alcohol and the like.

  The organic solvent is used in an amount of 1 to 100 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the total amount of the photopolymerizable monomer and / or photopolymerizable polymer.

  Furthermore, the photocurable composition of the present invention may contain a polymerization inhibitor such as 2,6-di-tert-butyl-p-cresol, hydroquinone, and p-methoxyphenol as necessary; eosin, methylene blue, malachite green, and the like. Sensitizers such as 2,4-diethylthioxanthone and 2-ethylanthraquinone; polymerization initiators other than the photopolymerization initiator of the present invention such as benzyldimethyl ketal and benzoin isopropyl ether may be mixed.

  The blending amount of the polymerization inhibitor is 0.001 to 5 parts by weight, preferably 0.01 to 1 part by weight with respect to 100 parts by weight of the total amount of the photopolymerizable monomer and / or photopolymerizable polymer. The blending amount of the polymerization initiator other than the dye, the sensitizer and the photopolymerization initiator of the present invention is 0.01 to 10 parts per 100 parts by weight of the total amount of the photopolymerizable monomer and / or photopolymerizable polymer. Part by weight, preferably 0.01 to 3 parts by weight is desirable.

  The photocurable composition thus obtained can be cured by irradiating energy rays such as visible light and ultraviolet rays in a state where the organic solvent is evaporated or left. Specifically, for example, by applying a photocurable composition on a smooth aluminum plate or glass plate so that the film thickness is 0.1 to 200 μm, and irradiating energy rays such as visible light and ultraviolet rays. A resin can be obtained.

  Examples of the light source of energy rays such as visible light and ultraviolet light include a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a xenon lamp, a germicidal lamp, and a laser beam. The irradiation time varies depending on the light source to be used, the type of polymerization initiator, and the amount used, and thus cannot be defined unconditionally, but is usually 0.1 second to 10 hours, preferably 0.1 minute to 1 hour.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these Examples.

Example 1
A 300 mL four-necked flask was charged with 34.5 g (0.15 mol) of bis (4-methylphenyl) sulfoxide and 32.7 g (0.15 mol) of diphenyl disulfide, and 128.4 g of methanesulfonic acid (1. 34 mol) was added dropwise at 20 ° C. over 1 hour. Subsequently, 30.0 g (0.29 mol) of acetic anhydride was added dropwise over 1 hour while maintaining the temperature at 40 ° C. or lower, and the mixture was reacted at 40 ° C. or lower for 1 hour.

  500 g of water was charged into a 1 L four-necked flask, and the reaction solution was added dropwise at 20 ° C. over 0.5 hour, followed by stirring for 1 hour. The reaction solution was neutralized by adding dropwise 320 g (2 mol) of 25 wt% sodium hydroxide aqueous solution at 20 ° C. over 0.5 hour. Next, 41.2 g (0.15 mol) of potassium hexafluoroantimonate was added at 20 ° C., and the mixture was vigorously stirred for 1 hour. After adding 200 g of dichloromethane and filtering insoluble matter, the dichloromethane layer was concentrated and purified by a column (Wakogel C-200, 800 g, chlorobenzene / n-hexane = 1/9, Rf = 0.3). 13.0 g of bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate was obtained. The yield based on bis (4-methylphenyl) sulfoxide was 13.0%. The purity of the obtained bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate was 96.0% as measured by high performance liquid chromatography. The obtained bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate could be identified from the following physical properties.

Melting point: 73.4 ° C
Elemental analysis: C; 46.7%, H; 3.6%, F; 17.1%, S; 14.3%, Sb; 18.3% (theoretical value: C; 46.79%, H; (3.47%, F; 17.08%, S; 14.41%, Sb; 18.24%)
IR (KBr, cm ⁻¹ ): 3057, 2912, 1439, 1336, 1072, 874, 808, 749, 705, 688, 499
1H-nuclear magnetic resonance spectrum (270 MHz, CDCl ₃ ) δ (ppm): 2.22 (s, 3H), 2.33 (s, 3H), 6.74 (s, 1H), 7.02 (d, 3H), 7.14-7.33 (m, 13H)
Maximum absorption wavelength: 253 nm

Example 2
A 300 mL four-necked flask was charged with 35.7 g (0.15 mol) of bis (4-fluorophenyl) sulfoxide and 32.7 g (0.15 mol) of diphenyl disulfide, and 128.4 g of methanesulfonic acid (1. 34 mol) was added dropwise at 30 ° C. over 1 hour. Subsequently, 30.0 g (0.29 mol) of acetic anhydride was added dropwise over 1 hour while maintaining the temperature at 50 ° C. or lower, and the mixture was reacted at 50 ° C. or lower for 1 hour.
500 g of water was charged into a 1 L four-necked flask, and the reaction solution was added dropwise at 20 ° C. over 0.5 hour, followed by stirring for 1 hour. The reaction solution was neutralized by adding dropwise 320 g (2 mol) of 25 wt% sodium hydroxide aqueous solution at 20 ° C. over 0.5 hour. Next, 41.2 g (0.15 mol) of potassium hexafluoroantimonate was added at 20 ° C., and the mixture was vigorously stirred for 1 hour. After adding 200 g of dichloromethane and filtering insoluble matter, the dichloromethane layer was concentrated and purified by a column (Wakogel C-200, 800 g, chlorobenzene / n-hexane = 1/9, Rf = 0.3). Bis (4-fluorophenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate 12.2 g was obtained. The yield based on bis (4-fluorophenyl) sulfoxide was 12.0%. The purity of the obtained bis (4-fluorophenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate was 98.0% as measured by high performance liquid chromatography. The obtained bis (4-fluorophenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate could be identified from the following physical properties.

Melting point: 94.4 ° C
Elemental analysis: C; 42.7%, H; 2.6%, F; 22.1%, S; 14.5%, Sb; 18.1% (theoretical value: C; 42.68%, H; 2.54%, F; 22.51%, S; 14.24%, Sb; 18.03%)
IR (KBr, cm ⁻¹ ): 3060, 1446, 1240, 1077, 870, 810, 755, 700, 683, 499
1H-nuclear magnetic resonance spectrum (270 MHz, CDCl ₃ ) δ (ppm): 6.74-7.33 (m, 17H)
Maximum absorption wavelength: 245nm

Example 3
In a 50 mL beaker, 2 g of a compound obtained by glycidyl etherification of bisphenol A (trade name of Yuka Shell; Epicoat 828), 0.11 g of propylene carbonate, bis (4-methylphenyl) -4 obtained in Example 1 -(Phenyldithio) phenylsulfonium hexafluoroantimonate (16 mg) was charged, and the mixture was stirred and mixed at 25 ° C. for 30 minutes to obtain a photocurable composition.

Example 4
A photocurable composition was obtained in the same manner as in Example 3 except that the amount of bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate used in Example 3 was changed from 16 mg to 80 mg. I got a thing.

Example 5
A photocurable composition was obtained in the same manner as in Example 3 except that the amount of bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate used in Example 3 was changed from 16 mg to 40 mg. I got a thing.

Example 6
A photocurable composition was obtained in the same manner as in Example 3 except that the amount of bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate used in Example 3 was changed from 16 mg to 4 mg. I got a thing.

Example 7
In a 50 mL beaker, 2 g of a compound obtained by glycidyl etherification of bisphenol A (trade name of Yuka Shell; Epicoat 828), 0.11 g of propylene carbonate, bis (4-fluorophenyl) -4 obtained in Example 2 -(Phenyldithio) phenylsulfonium hexafluoroantimonate (16 mg) was charged, and the mixture was stirred and mixed at 25 ° C. for 30 minutes to obtain a photocurable composition.

Example 8
A photocurable composition was obtained in the same manner as in Example 7 except that the amount of bis (4-fluorophenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate used in Example 7 was changed from 16 mg to 40 mg. I got a thing.

Comparative Example 1
In Example 3, except that 16 mg of tris (4-methylphenyl) sulfonium hexafluoroantimonate was used instead of 16 mg of bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate In the same manner as in No. 3, a photocurable composition was obtained.

Comparative Example 2
In Example 3, in place of 16 mg of triphenylsulfonium tetrafluoroborate instead of 16 mg of bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate, the same as in Example 3, A photocurable composition was obtained.

Comparative Example 3
In Example 3, except that 16 mg of diphenyl-4- (phenylthio) phenylsulfonium hexafluoroantimonate was used instead of 16 mg of bis (4-methylphenyl) -4- (phenyldithio) phenylsulfonium hexafluoroantimonate In the same manner as in No. 3, a photocurable composition was obtained.

Measurement of Curing Rate 1 g of the photocurable composition obtained in Examples 3 to 8 and Comparative Examples 1 to 3 was added to bar coater No. 22 (manufactured by Nippon Cedars Co., Ltd.) was applied onto an aluminum plate so as to have a film thickness of 50 μm, and a 60 W metal halide lamp (trade name: UVL-3001M2-N1 manufactured by USHIO INC.) Was used as the light source Then, light irradiation was performed at a light intensity of 200 mW / cm ² for 30 seconds. After light irradiation, the coated surface was touched with a finger, and light irradiation was repeated until stickiness disappeared, and the number of times of light irradiation was measured to determine the curing rate. In addition, if the frequency | count of light irradiation is 2 times or less, it can be judged that a cure rate is quick. The results are shown in Table 1.

  As is clear from Table 1, the photocurable composition of the present invention can be judged to have a high curing rate because the number of times of light irradiation is 2 or less.

The photocurable composition containing the photopolymerization initiator of the present invention has a high curing rate and can be used as a printing plate making material, various resists, an ultraviolet curable coating, and the like.

Claims (4)

The following general formula (1);

(In the formula, R ^{1 to} R ¹⁹ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms, X ⁻ represents an inorganic acid ion or an organic acid ion, and n represents 2 to 5). Indicates an integer.)
An aromatic sulfonium salt represented by In the general formula (1), R ³ and R ⁸ are the same and are a halogen atom or an alkyl group having 1 to 10 carbon atoms, and R ¹ , R ² , R ^{4 to} R ⁷ and R ^{9 to} R ¹⁹ are The aromatic sulfonium salt according to claim 1, which is a hydrogen atom.   A photopolymerization initiator comprising the aromatic sulfonium salt according to claim 1 or 2. The photocurable composition containing a photopolymerizable monomer and / or a photopolymerizable polymer, and the photoinitiator of Claim 3.