JPH10338688A - New sulfonium salt and photosensitive resin composition using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound useful for curing, etc., for epoxy resins as a photocation polymerization initiator. SOLUTION: This sulfonium salt is represented by the formula (R is a conjugated five-membered ring or a condensed polycyclic group comprising the conjugated fiber-membered ring and one or more benzene rings; P and Q are each independently an alkyl or P, Q and S are connected to form a 4 or 5C ring; X<-> is a Lewis acid residue having weak nucleophilic property), e.g. antimonate hexafluoride dialkylthienoyl sulfonium salt. The compound of the formula is obtained by dissolving an acetyl derivative into a mixed solvent such as dichloromethane-methanol, adding tetrabutylammonium tribromide thereto and subjecting the mixture to stirring reaction to afford a bromoacetyl derivative and reacting the bromoacetyl derivative with a dialkyl sulfide (in which P and Q are each an alkyl) in a mixed solvent of acetone with water. A photosensitive resin composition obtained by using the compound of the formula as a photocation polymerization initiator has large molecular extinction coefficient and high polymerization activity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel sulfonium salt which can be used as a cationic photopolymerization initiator, for example, for curing an epoxy resin.

[0002]

2. Description of the Related Art A cationic photopolymerization initiator is a substance that absorbs an energy ray such as ultraviolet energy and releases a catalyst component for initiating cationic polymerization. For example, curing of an epoxy resin, various cyclic ethers, cyclic esters, and cyclic resins. It is used in polymerization and curing reactions of organosilicon compounds and polyfunctional vinyl ethers.

A typical example of such a cationic photopolymerization initiator is disclosed in US Pat. No. 3,205,15.
7 and 3,708,296, and aryldiazonium salts of halogen-containing complex anions, and U.S. Pat.
No. 951, the aromatic onium salts of Group VIa elements described in US Pat. Nos. 4,058,401 and 4,138,255, and the like. And dialkylphenacylsulfonium salts described in JP-A-59-147001.

However, among these known cationic photopolymerization initiators, for example, those based on diazonium salts have poor storage stability in a resin, and bubbles are generated in the coating film due to by-produced nitrogen by light irradiation. In the case of dialkylphenacylsulfonium salts, there is a problem that the molecular extinction coefficient is relatively small. Further, in the case of an onium salt such as a triarylsulfonium salt or an iodonium salt, when this is actually used for, for example, curing an epoxy resin or the like, it can be said that it is not always satisfactory in terms of curing speed. Absent.

Furthermore, since the maximum absorption wavelength of any of these photocationic polymerization initiators is 300 nm or less, there is a problem that the curing speed is reduced under the condition of using a light source of 300 nm or more. For this reason, there has been a long-awaited need for a new photocationic polymerization initiator having a higher sensitivity in a longer wavelength region, a faster curing property, and a higher polymerization activity.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned situation, and is expected to be used as a cationic photopolymerization initiator. The present invention has been found to have an activity and exhibit excellent fast-curing properties when used as a curing agent such as an epoxy resin.

Accordingly, the present invention has a large molecular extinction coefficient at 300 nm or more, has a high polymerization activity, and exhibits excellent rapid curing properties when this is used as a curing agent such as an epoxy resin. It is to provide a novel sulfonium salt useful as a polymerization initiator and a photosensitive resin composition using the same.

[0008]

That is, the present invention provides a compound represented by the following general formula (1):

Embedded image (Wherein, R is a conjugated five-membered ring or a conjugated five-membered ring and 1
A condensed polycyclic ring with two or more benzene rings, wherein P and Q each independently represent alkyl, or P, Q and S are linked to form a ring having 4 or 5 carbon atoms, X ^- is a sulfonium salt represented by showing a weak Lewis acid residues having nucleophilic).

Further, the present invention is a photosensitive resin composition comprising at least a sulfonium salt represented by the above general formula (1) as a cationic photopolymerization initiator.

In the sulfonium salt of the present invention represented by the general formula (1), X ^- is a Lewis acid residue having a weak nucleophilic property. Any Lewis acid that is a weak Lewis acid and may be a Lewis acid residue that can be liberated to form a Bronsted acid, such as BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ ,
AsF _6- ^{and the} like.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The sulfonium salt of the present invention is described, for example, in Bull. Chem. Soc. Jpn., 60, 1159 (1987) and J. Pol.
According to the method described in ym. Sci. Polym. Chem. Ed., 17, 2877 (1979), it can be easily synthesized generally as follows.

That is, the acetyl derivative is dissolved in a suitable solvent, for example, a mixed solvent of a halogenated hydrocarbon such as dichloromethane, dichloroethane, chloroform and tetrachloroethane and an alcohol such as methanol, and tetrabutylammonium tribromide is added thereto at room temperature. And react with stirring for 1 hour. After completion of the reaction, the solvent is distilled off, and the precipitate is extracted with ether. The ether layer is dried over magnesium sulfate, and the product obtained by evaporating the solvent is recrystallized with a mixed solvent of ethanol and water to obtain a bromoacetyl derivative.

The obtained bromoacetyl derivative, dialkyl sulfide (when P and Q each independently represent alkyl in the general formula (1)), and tetrahydrothiophene (P and Q are linked to and adjacent to each other in the general formula (1)) A case where a five-membered ring is formed together with a sulfur atom) or tetrahydrothiopyran (a case where P and Q are linked to form a six-membered ring with an adjacent sulfur atom in the general formula (1))
Is stirred at 25 ° C. for 1.5 hours in a mixed solvent of acetone and water, and the resulting bromo salt is washed several times with diethyl ether, filtered and air-dried. An aqueous solution of a silver salt or an alkali metal salt of a weak nucleophilic Lewis acid is added to an aqueous solution of a bromo salt,
If the crystallized salt is filtered, washed with water, dried and then recrystallized with water or a mixed solvent of water and alcohol,
The desired sulfonium salt is easily obtained.

The sulfonium salt of the present invention or a solvent adduct thereof has use as a cationic photopolymerization initiator for monomers, oligomers, low molecular weight polymers and the like. When the sulfonium salt of the present invention or a solvent adduct thereof is used as a cationic photopolymerization initiator, these may be used alone or in combination of two or more.
Further, it may be optionally used in combination with other cationic photopolymerization initiators, photosensitizers and the like.

The cationic photopolymerization initiator of the present invention comprising a sulfonium salt or a solvent adduct thereof has excellent storage stability in an epoxy resin and does not produce nitrogen by light irradiation, so that it can be applied to a coating film. It has the feature that it does not generate bubbles, and has a large molecular extinction coefficient especially at 300 nm or more, and has a higher curing rate than the conventional photocationic polymerization initiator.

The cationic photopolymerization initiator comprising the sulfonium salt of the present invention includes, for example, bisphenol A diglycidyl ether type epoxy resin (DGEBA), phenol novolak type epoxy resin, orthocresol novolak type epoxy resin, glycidyl ether type epoxy resin,
Epoxy compounds such as alicyclic epoxy resins, methyl-substituted epoxy resins, glycidyl ester type epoxy resins,
Isobutylene, styrene, α-methylstyrene, butadiene, vinyl monomers such as vinyl alkyl ethers or oligomers or low molecular polymers thereof, cyclic organic ethers, cyclic organic esters, cyclic organic sulfides,
It can be effectively used for a photopolymerizable or photocurable substance such as a cyclic amine, a cyclic organosilicon compound, and a cationically polymerizable compound such as a polyfunctional vinyl ether.

Further, the photosensitive resin composition of the present invention is characterized in that the sulfonium salt of the present invention is blended as an essential component with the above-mentioned cationically polymerizable compound. The sulfonium salt can be added in an amount of 0.1 to 15 parts by weight, more preferably 3 to 10 parts by weight, based on 100 parts by weight of the cationically polymerizable compound. If the amount is less than 0.1 part by weight, the polymerization reaction rate is extremely lowered, and it becomes difficult to form a good coating film, which is not preferable. On the other hand, when the amount exceeds 15 parts by weight, the light transmittance is lowered and the polymerization reaction rate is lowered, and unreacted initiators and decomposed products are left in a large amount in the coating film.

Further, when the epoxy resin is used as the cationically polymerizable compound, the photosensitive resin composition of the present invention contains phthalic anhydride,
It is also possible to add an acid anhydride such as pyromellitic acid or tetrahydrophthalic acid in an amount less than 90% equivalent to the epoxy resin. 90% of this acid anhydride based on epoxy resin
If the amount is more than the equivalent, unreacted acid anhydride remains in the coating film, and this is not preferable because the moisture resistance and strength of the coating film are reduced.

Further, a non-polymerizable diluent can be added to the photosensitive resin composition of the present invention for the purpose of making the viscosity appropriate. Examples of such a non-polymerizable diluent include ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, isopropyl alcohol, toluene, xylene and the like. Since the appropriate viscosity of the coating material varies greatly depending on the coating method, the type of coating material, the coating speed, and the film thickness, the amount of the diluent used can be any ratio. However, these non-polymerizable diluents must be largely volatilized by the heat drying process. When a large amount remains, serious defects often occur in the surface hardness and adhesion of the coating film.

The photosensitive resin composition of the present invention may further contain other components, for example, a pigment, a filler, a surfactant, a dispersant, and the like for the purpose of coloring, hiding, etc. It is also possible to add agents, plasticizers, antioxidants and the like.

[0021]

EXAMPLES The sulfonium salt of the present invention will be specifically described below based on examples and test examples. However, the present invention is not limited to these examples.

[0022] R is a thienyl group in Example 1 hexafluoride antimonate dialkyl Chie noil sulfonium salts [general formula (1), P and Q together form a tetrahydrothiophene ring together with the adjacent sulfur atom, X ^- = SbF ₆ ^- the material] was synthesized as follows. 10 g of acetylthiophene was dissolved in 1300 ml of a mixed solvent of dichloromethane and methanol, 42 g of tetrabutylammonium tribromide was added at room temperature and reacted for 1 hour with stirring, the solvent was distilled off, and the precipitate was extracted with ether. The ether layer was dried over magnesium sulfate, the solvent was distilled off, and the residue was recrystallized with a mixed solvent of ethanol and water to obtain bromomethylthienyl ketone.

The obtained bromomethylthienyl ketone 10
g and 4.3 g of tetrahydrothiophene were stirred in 50 ml of a mixed solvent of acetone and water at 25 ° C. for 1.5 hours, and the resulting bromo salt was washed several times with diethyl ether, filtered and air-dried. 70 ml of an aqueous solution of 10 g of the obtained bromo salt
34 ml of an equimolar amount of an aqueous solution of silver hexafluoride antimonate was added thereto, and the crystallized salt was filtered, washed with water, and dried.
Recrystallize with a water-alcohol mixed solvent to obtain the desired crystal (dialkylthienoylsulfonium hexafluoroantimonate)
15 g were obtained.

With respect to the obtained crystal, melting point, elemental analysis,
UV, IR, and NMR measurements were made. The results were as follows. Melting point (mp): 152~154 ℃ Elemental analysis _{(C 10 H 13 OF 6 SSb} ): Calculated (%) C: 26.7, H : 2.90 Found (%) C: 26.4, H : 2.67 UV (λ _max ): 295 nm (ε = 8582), 265
nm (ε = 9147) IR (cm ⁻¹ ): 1660 (C = O), 650 (SbF
^{_{6 -) NMR (DMSO-d}} 6; δppm): 7.38 (1H,
dd, J = 1.5, 4.9Hz), 7.22 (1H, dd, J = 1.5, 3.5H)
z), 6.54 (1H, dd, J = 3.5, 4.9 Hz), 4.39 (2
_{H, s, -CH 2 -)} , 2.6~3.0,1.3~1.6 (8H,
m, tetrahydrothiophene)

Example 2 Dialkylfluorenoylsulfonium hexafluoride antimonate [In the formula (1), R is a fluorenyl group,
Q together with, form a tetrahydrothiophene ring together with the adjacent sulfur atom, X ^- = SbF ₆ ^- substances]
Was synthesized as follows. Acetylfluorene 10
g in dichloromethane-methanol mixed solvent 1300ml
After adding 42 g of tetrabutylammonium tribromide at room temperature and reacting with stirring for 1 hour, the solvent was distilled off and the precipitate was extracted with ether. The ether layer was dried over magnesium sulfate, the solvent was distilled off, and recrystallized with a mixed solvent of ethanol and water to obtain bromomethylfluorenyl ketone.

10 g of the obtained bromomethylfluorenyl ketone and 4.3 g of tetrahydrothiophene were stirred in 50 ml of an acetone-water mixed solvent at 25 ° C. for 1.5 hours,
The resulting bromo salt was washed several times with diethyl ether, filtered and air-dried. Aqueous solution 70 of 10 g of the obtained bromo salt
34 ml of an aqueous solution of silver hexafluoride antimonate in an equimolar amount per ml
Was added, and the crystallized salt was filtered, washed with water, dried, and then recrystallized with a water-alcohol mixed solvent to obtain 15 g of the desired crystal (dialkylfluorenoylsulfonium hexafluoroantimonate). .

The obtained crystals were analyzed for melting point, elemental analysis,
UV, IR, and NMR measurements were made. The results were as follows. Melting point (mp): 138~143 ℃ Elemental analysis _{(C 19 H 19 OSF 6 Sb} ): Calculated (%) C: 43.0, H : 3.60 Found (%) C: 42.8, H : 3.48 UV (λ _max ): 322 nm (ε = 24687) IR (cm ⁻¹ ): 1670 (C = O), 650 (SbF)
^{_{6 -) NMR (DMSO-d}} 6; δppm): 7.4~8.3
(7H, m, Aromatic H) , 5.4 (2H, s, -CH 2 -),
4.1 (2H, s, fluorene), 3.4 to 3.7, 2.1
~ 2.4 (8H, m, tetrahydrothiophene)

Example 3 Commercially available epoxy resins shown in Table 1 [namely, celloxide 2021P (2021P) manufactured by Daicel Chemical Industries, Epicoat 828 (# 828) manufactured by Yuka Shell Co., Ltd., and Nippon Steel Chemical Co., Ltd.] After mixing 3% by weight of the sulfonium salt of the present invention obtained in Example 1 with respect to the trade name ESF300 (FE)], the mixture was applied on a glass plate so as to have a thickness of about 30 μm. (120 W / cm), using an ultraviolet irradiation device having an irradiation time shown in Table 1, to cure by irradiation with an ultraviolet ray, and the surface state after the curing was determined by an acetone rubbing method [that is, 500 g / cm 2 using a cotton cloth soaked in acetone. cm
A method of rubbing the surface with a pressure of about ² and observing a change in the surface], ◎: extremely good, ：: good, □: tackiness remains, Δ: wrinkles, and ×: sticky. It was evaluated on a scale. Table 1 shows the results.

Similarly, the sulfonium salt obtained in Example 1 was added to the commercially available epoxy resin shown in Table 1.
Weight%, and then applied on a glass plate to a thickness of about 30 μm, at 100 ° C. for 60 minutes, at 150 ° C. for 30 minutes,
And heat curing at 200 ° C. for 20 minutes, and the surface state after the curing was tested and evaluated by an acetone rubbing method.
Table 1 shows the results.

Further, 3% by weight of the sulfonium salt obtained in Example 1 was mixed with a commercially available epoxy resin shown in Table 1 and applied to a glass plate so as to have a thickness of about 30 μm.
After UV irradiation for the irradiation time shown in Table 1 in the same manner as above, thermal curing was performed at 150 ° C. for 30 minutes, and the surface state after curing was tested and evaluated by an acetone rubbing method. Table 1 shows the results.

[0031]

[Table 1]

Example 4 A commercially available epoxy resin shown in Table 2 [namely, celloxide 2021P (2021P) manufactured by Daicel Chemical Industries, Epicoat 828 (# 828) manufactured by Yuka Shell Co., Ltd.) was used in Example 2. With the sulfonium salt of the present invention obtained in
After mixing, the composition was applied on a glass plate so as to have a thickness of about 30 μm, and was cured by irradiating with ultraviolet light for an irradiation time shown in Table 2 using an ultraviolet irradiation device equipped with a high-pressure mercury lamp (120 W / cm). The surface condition after curing was tested by the acetone rubbing method, and evaluated in the same manner as in Example 3. Table 2 shows the results.

Similarly, 3% by weight of the sulfonium salt obtained in Example 2 was mixed with a commercially available epoxy resin shown in Table 2 and then applied on a glass plate so as to have a thickness of about 30 μm. 60 ° C. for 30 minutes, 150 ° C. for 30 minutes, and 20
Thermal curing was performed at 0 ° C. for 30 minutes, and the surface state after curing was tested and evaluated by an acetone rubbing method. Table 2 shows the results.

Further, 3% by weight of the sulfonium salt obtained in Example 2 was mixed with a commercially available epoxy resin shown in Table 2 and applied to a glass plate so as to have a thickness of about 30 μm.
After UV irradiation for the irradiation time shown in Table 2 in the same manner as above, heat curing was performed at 150 ° C. for 30 minutes, and the surface state after curing was evaluated by an acetone rubbing method. Table 2 shows the results.

[0035]

[Table 2]

As is evident from Tables 1 and 2, the sulfonium salt of the present invention exhibits excellent quick-curing properties by ultraviolet irradiation to any of the epoxy resins and also has excellent thermosetting properties. Furthermore, when ultraviolet irradiation and heat curing are used in combination, more excellent curability (pencil hardness 5H) can be obtained with any epoxy resin, and both adhesion to glass and bending resistance (2 mmφ) are good. Met.

Here, the synthesis of the sulfonium salt in which P and Q are linked to each other to form a cycloalkyl having 4 carbon atoms in the general formula (1) has been described, but as described above, instead of tetrahydrothiophene, By using tetrahydrothiopyran and dialkyl sulfide,
Similarly, a sulfonium salt in which P and Q are linked to each other to form cycloalkyl having 5 carbon atoms in Formula (1), and a sulfonium salt in which P and Q are each independently alkyl are easily synthesized in the same manner. be able to. Further, in the general formula (1), the polymerization activities of the different sulfonium salts in which P and Q are substituted as described above are almost the same when they have the same R and X ⁻ , and the same as in the phenacyl sulfonium salt. Of a comparative experiment (Macr
omolecules, 16,864 (1983)).

Here, in the general formula (1), R
Described the synthesis of sulfonium salts in which is a thienyl group and a fluorenyl group.By using other acetyl derivatives of a conjugated five-membered ring and a condensed polycyclic compound, a sulfonium salt having each as R was prepared by the method already described. Similarly, they can be synthesized.

[0039]

The present invention provides a novel sulfonium salt having a use as a photocationic polymerization initiator. Particularly, when the sulfonium salt is used as a photocationic polymerization initiator, the sulfonium salt has a longer wavelength region than conventional ones. The present invention exhibits excellent performance such as excellent fast curing properties when used for curing epoxy resins, for example, and is a great invention contributing to the industry.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hironobu Kawasato 3-35-1, Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture, within the Technology Development Division of Nippon Steel Corporation (72) Inventor Koichi Fujishiro Nakahara, Kawasaki-shi, Kanagawa 3-35-1, Ida-ku, Nippon Steel Corporation Technology Development Division

Claims (2)

[Claims] [Claim 1] The following general formula (1) (Wherein, R is a conjugated five-membered ring or a conjugated five-membered ring and 1
A condensed polycyclic ring with two or more benzene rings, wherein P and Q each independently represent alkyl, or P, Q and S are linked to form a ring having 4 or 5 carbon atoms, X ^- sulfonium salt represented by displays a weak Lewis acid residues having nucleophilic). 2. A photosensitive resin composition comprising at least the sulfonium salt according to claim 1 as a cationic photopolymerization initiator.