JPH10245378A - New sulfonium salt and photopolymerization initiator and energy ray curing composition comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new sulfonium salt, having a phenothiazine structure in the molecule and useful as a photopolymerization initiator. SOLUTION: This sulfonium salt is represented by formula I X is a group represented by formula II (R9 to R18 are each H, a halogen, a nitro, a substitutable alkoxy or a substitutable alkyl); R1 to R8 are each H, a halogen, an alkyl, an alkoxy or COOR (R is a 1-4C hydrocarbon), CY3 (Y is a halogen) or formula II; Z is an anion represented by the formula MQp-m (OH)m [M is P, As or Sb; Q is halogen; (p) is 4 to 6; (m) is 0 or 1] or the formula BYa Rb [(a) and (b) are each 0 to 4 and (a+b)=4; Y is a halogen or OH; R is an electron withdrawing group or a halogen-substituted phenyl]; (n) is 1 or 2}. This compound is obtained by carrying out the condensation reaction of a phenothiazine-based compound represented by formula III with a substituted or unusbstituted diphenyl sulfoxide compound in the presence of a dehydrating agent, then mixing the resultant compound with a solution of an alkali metallic salt containing the formula MQp-m (OH)m or the formula BYa Rb as an anionic part and conducting a metathetic reaction. An energy ray curing composition, containing the compound of formula I, excellent in durability and capable of providing a cured product thereof excellent in gloss, etc., is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel sulfonium salt, a photopolymerization initiator comprising the same, an energy ray-curable composition containing the same, which can be cured by irradiation with energy rays, and a cured product thereof.

[0002]

2. Description of the Related Art Photopolymerizable compositions have been intensively studied in the fields of printing inks, paints, coatings, liquid resist inks, etc. from demands for energy saving, space saving, and pollution-free, and their practical use has been studied. . However, most of these studies were based on radical polymerization reactions of double bonds. Cationic polymerizable substances, such as epoxy resins, are excellent in physical properties, but are difficult to photopolymerize, and so far, materials that have been modified with acrylic to introduce double bonds have been mainly used. .

[0003]

In curing an epoxy resin by light, for example, US Pat.
No. 76 proposes a method in which a photosensitive aromatic diazonium salt is used as a photopolymerization initiator, the photopolymerization initiator is decomposed by light irradiation, and a Lewis acid is released to polymerize the epoxy resin. However, the aromatic diazonium salt releases nitrogen gas at the same time as the Lewis acid by photolysis, so that when the film thickness of the epoxy resin is 15 μm or more, the coating film foams and is not suitable for thick coating. Furthermore, a mixture of an epoxy resin and a photopolymerization initiator has a problem in storage stability such that curing gradually proceeds even when no light is present, and is difficult to use as a one-part composition.

Various studies have been made to overcome the above-mentioned drawbacks of the diazonium salt-based initiator, and aromatic sulfonium salt-based and aromatic iodonium salt-based initiators and the like have been proposed as techniques for improving thick coating properties and storage stability. The curable resin composition containing is disclosed in JP-B-52-14278 and JP-B-Sho 5-14278.
These are disclosed in, for example, JP-A-2-14277, JP-A-54-53181, and JP-B-59-19581. However, compositions containing these aromatic onium salts have a disadvantage that they are poor in curability as compared with diazonium salts, and in the case of aromatic sulfonium salts, the odor of the cured product has been a problem. In order to overcome such a drawback, an aromatic sulfonium salt having a specific group has been proposed in JP-A-56-55420 and the like. But,
The above disadvantages have been alleviated, albeit somewhat, but not fully. Further, curing with a pigment system is insufficient, and no proposal has been made. Under these circumstances, as the field of use of the photopolymerizable composition expands, it is important to provide a novel photopolymerization initiator or a composition containing the same in order to meet market demands. It is an issue.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found a novel photopolymerization initiator. The present invention was found to be excellent in curability, and in particular, to show excellent curability even in a pigment system.

That is, the present invention provides (1) a photosensitive sulfonium salt having a phenothiazine structure in the molecule, (2)
The following general formula (1)

[0007]

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Wherein X is a group represented by the formula (2):

[0009]

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(Wherein, R _{9 to} R ₁₈ are each a hydrogen atom, a halogen atom, a nitro group, an optionally substituted alkoxy group or an optionally substituted alkyl group. Wherein R _{1 to} R ₈ are each a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, -COOR (R is a hydrocarbon group having 1 to 4 carbon atoms),-
CY ₃ (Y is a halogen atom) or a group represented by the formula (2), which may be the same or different. Party B

[0011]

Embedded image MQ _pm (OH) _m (3)

Wherein M is a phosphorus atom, an arsenic atom or an antimony atom, Q is a halogen atom, P is an integer of 4 to 6, and m is 0 or 1.

[0013]

Embedded image BY _a R _b (4)

Wherein B is a boron atom, and a and b are 0 to
An integer of 4, where a + b is 4, Y represents a halogen atom or a hydroxyl group, and R represents a phenyl group substituted with at least one electron-withdrawing group or at least two halogen atoms. ) Wherein n is 1 or 2; and (3) a photopolymerization initiator (B) comprising the sulfonium salt according to the item (1) or (2); (5) An energy ray-curable composition comprising the cationic polymerizable substance (A) and the photopolymerization initiator (B) according to the item (3);
(4) a cured product of the energy ray-curable composition according to the item,
About.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The sulfonium salt of the present invention, for example, a sulfonium salt represented by the general formula (1) is, for example, 1) a phenothiazine compound represented by the general formula (5)

[0016]

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[0017] (wherein, R ₁ to R ₈ in general formula (1) is identical to R ₁ to R ₈ in.) And using the generated reaction of substituted or unsubstituted diphenyl sulfoxide compound known sulfonium salts (Hereinafter referred to as method 1) or 2) a method of converting and introducing corresponding substituted and unsubstituted groups (hereinafter referred to as method 2)). First, the method 1) will be described specifically. Phenothiazine compounds represented by the formula (5) (as specific examples, phenothiazine, 2-chlorophenothiazine, 2- (trifluoromethyl) phenothiazine, 2-acetylphenothiazine, 2-methoxyphenothiazine, 2-chloro-1
0-propylphenothiazine, 10-butylphenothiazine, etc.) and substituted or unsubstituted diphenylsulfoxide compounds (for example, diphenylsulfoxide, 4,4'-difluorodiphenylsulfoxide, 4,4-dichlorodiphenylsulfoxide, 4,4'-dibromodiphenylsulfoxide) 4,4'-dimethylphenylsulfoxide, 4,4'-diethyldiphenylsulfoxide, 4,
4'-dimethoxydiphenylsulfoxide, 4,4'-
Diethoxydiphenylsulfoxide) in a solvent such as methanesulfonic acid, ethanesulfonic acid, or perfluoromethanesulfonic acid in the presence of a dehydrating agent (eg, phosphorus pentoxide, acetic anhydride, concentrated sulfuric acid, etc.), usually at room temperature. ~ 100 ° C
And then reacting the reaction mixture with an alkali metal salt having an anion of formula (3) or (4) (eg, NaSbF ₆ , NaPF ₆ , NaBF ₄ , NaSbF ₅ OH, KSbF ₆ , KP
_{F 6, KAsF 6, KSbF 5} OH, LiB (C 6 F 5) 4, LiB (C 6 F 5) 2 F 2, Li
B (C ₆ H ₄ CF ₃ ) ₄ , NaB (C ₆ F ₅ ) ₄ , LiBF ₃ (C ₆ F ₅ ), LiB (C ₆ H
_The metathesis reaction can be carried out by mixing the solutions of ₃ F ₂ ) ₄ etc.). Next, a desired sulfonium salt can be obtained by a known recovery method, for example, recrystallization, filtration and the like.

The method 2) is specifically described below. A sulfonium salt synthesized by the method 1), for example, a compound represented by the formula (6)

[0019]

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[0020] (wherein (6), R ₁ to R ₈ is A is a halogen atom the same as R ₁ to R ₈ in the formula (5), Z is the formula (3) or (4) A large excess of mono- or polyalcohols (eg, methanol, ethanol, etc.) in the presence of a basic compound (eg, sodium hydroxide, potassium hydroxide, potassium carbonate, etc.). Carbitol, ethylene glycol, polyethylene glycol, propylene glycol,
Glycerin, trimethylolpropane, 1,4-butanediol, glycidol, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, allyl alcohol, etc.) at room temperature to 150 ° C., if necessary, with dimethyl sulfoxide. By reacting in the presence of an organic solvent such as, the halide portion of the halide compound is, for example,

[0021]

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Thus, a sulfonium salt converted to the above substituents can be obtained. Specific examples of the compound represented by the general formula (1) include the compounds in Table 1.
It is not limited to these.

[0023]

[Table 1]

[0024]

[Table 2]

The curable composition of the present invention is used in an amount of usually 0.01 to 20 parts by weight per 100 parts by weight of the cationically polymerizable substance (A).
Parts by weight, preferably 0.1 to 10 parts by weight, of the sulfonium salt (B) represented by the above formula (1) are used as an essential component. , Dose, desired curing time, temperature, humidity, coating thickness and other factors are determined. In order to facilitate dissolution of the sulfonium salt in the cationically polymerizable substance, the sulfonium salt is previously dissolved in a solvent (eg, propylene carbonate, carbitol, carbitol acetate, butyrolactone, etc.).
Can be used after dissolution. The curable composition of the present invention can be prepared by a method such as mixing, dissolving or kneading a cationically polymerizable substance and a sulfonium salt.

The curable composition of the present invention can be cured to a dry-to-touch state or a solvent-insoluble state after 0.1 seconds to several minutes by irradiating energy rays such as ultraviolet rays. Any suitable energy ray may be used as long as it has an energy that induces the decomposition of the sulfonium salt. Preferably, the energy ray is a high- or low-pressure mercury lamp, a xenon lamp, a germicidal lamp, a laser beam, or the like.
Electromagnetic wave energy having a wavelength of Å to 7000 Å or high energy rays such as electron beams, X-rays, and radiations are used. Exposure to an energy ray depends on the intensity of the energy ray, but usually about 0.1 to 10 seconds is sufficient. However, it is preferred to spend more time on relatively thick painted objects. 0.1 seconds to several minutes after the irradiation with the energy beam, the composition is dried to the touch by cation polymerization. However, it is sometimes preferable to use heating in combination to promote the cation polymerization reaction.

The composition of the present invention further contains a solvent for dilution, a non-reactive resin for modification, and a (meth) acrylate compound (for example, bisphenol A) as long as the cationic polymerization is not impaired. Oligomers such as epoxy (meth) acrylate, urethane (meth) acrylate, and polyester poly (meth) acrylate, which are reactants of epoxy resin such as epoxy resin, novolak epoxy resin and (meth) acrylic acid, and 2-hydroxyethyl (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and other monomers). When a (meth) acrylate is used, a photo-radical polymerization initiator (for example, 1-hydroxycyclohexylphenyl ketone, acetophenone dimethyl ketal, benzoylmethyl ether, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc.) is used. It is preferred to use. Further, for example, an organic carboxylic acid or an acid anhydride may be used for the purpose of improving electric characteristics, or a polyol or other flexible prepolymer may be mixed for the purpose of imparting rubber elasticity.

The composition of the present invention may contain an inert pigment (for example, an inorganic pigment such as carbon black, graphite, molybdenum, red iron oxide, titanium dioxide or rutile-type titanium dioxide coated with aluminum oxide, cyanine, etc.). And organic pigments such as green, cyanine blue, Hansa Yellow, Benzidine Yellow, Brilliant Carmine 6B, Lake Red C, Permanent Red F5R, etc.), dyes, fillers, antistatic agents, flame retardants, defoamers Agents, flow regulators, sensitizers, accelerators, light stabilizers and the like can be mixed and used. The composition of the present invention can be used for metal, wood, rubber, plastic, glass, ceramic products and the like. Further, specific uses of the composition of the present invention include paints, coating agents, inks, resists, liquid resists, adhesives, molding materials, casting materials, putties, glass fiber impregnating agents, fillers, and the like. .

[0029]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. Parts in Examples are parts by weight. (Synthesis example of sulfonium salt represented by formula (1))

Example 1 19.9 parts of phenothiazine, 24 parts of 4,4'-difluorodiphenylsulfoxide, 50 parts of acetic anhydride and 200 parts of methanesulfonic acid were charged and reacted at 80 ° C. for about 8 hours, and then the reaction mixture was added. 6% NaSbF ₆ aqueous solution 43
1.2 parts were added, and the precipitated pale yellow solid was filtered, sufficiently washed with water, and then recrystallized from methanol to give a melting point of 1: 1.
The following sulfonium salt of 91-199 ° C was obtained as a pale yellow color.

[0031]

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The yield of the recrystallized product was 48 parts, and the elemental analysis values were as follows. Element Actual measured value (% by weight) Calculated value (% by weight) Carbon 44.01 43.92 Hydrogen 2.50 2.46 Sulfur 9.73 9.77 Nitrogen 2.09 2.13 Fluorine 23.07 23.16 Antimony 18 .44 18.55

Example 2 19.9 parts of phenothiazine, 23.2 parts of 4,4'-dimethylphenylsulfoxide, 50 parts of acetic anhydride and 200 parts of methanesulfonic acid were charged and reacted at 80 ° C. for about 8 hours. 6% NaPF ₆ aqueous solution 280
Was added, and the precipitated pale yellow crystals were filtered, sufficiently washed with water, and then recrystallized from methanol to give a melting point of 205-205.
A pale yellow compound of the following formula at 214 ° C. was obtained.

[0034]

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The yield of the recrystallized product was 40 parts, and the elemental analysis values were as follows. Element Actual measured value (% by weight) Calculated value (% by weight) Carbon 55.09 55.01 Hydrogen 5.73 5.68 Phosphorous 5.41 5.46 Sulfur 11.21 11.30 Nitrogen 2.46 2.47 Fluorine 20 .01 20.08

Example 3 30 parts of the sulfonium salt obtained in Example 1, 200 parts of ethylene glycol and 4.0 parts of NaOH were charged and reacted at 25 ° C. for 24 hours, and 1000 parts of water was added to the reaction mixture. The light yellow solid thus obtained was filtered, sufficiently washed with water, and dried to obtain a sulfonium salt represented by the following formula.

[0037]

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The melting point was 182 to 189 ° C., and the elemental analysis values were as follows. Element Actual measured value (% by weight) Calculated value (% by weight) Carbon 45.49 45.42 Hydrogen 3.61 3.54 Sulfur 8.70 8.66 Nitrogen 1.88 1.89 Fluorine 15.88 15.96 Antimony 16 .39 16.44

Examples 4 to 6 and Comparative Example 1 An energy ray-curable composition of the present invention or a comparative composition was compounded according to the compounding composition shown in Table 2 (the numerical values are parts by weight) and kneaded with a three-roll mill. . This was applied on an aluminum plate to a thickness of 7 μ with a bar coder, and irradiated with 200 mJ / cm ^{2 of} ultraviolet rays from a distance of 8 cm with a metal halide lamp (80 w / cm ² ) to be cured. The curability of each prepared composition and the gloss of the cured coating film were tested. Table 3 shows the results.

Curability: The cured coating was left for 24 hours, rubbed 50 times with absorbent cotton impregnated with methyl ethyl ketone, and the appearance of the coating was observed. ○ ・ ・ ・ ・ No abnormality in the coating film. Δ: The gloss of the coating film is slightly reduced. X: The coating film was dissolved. Mitsuzawa: The surface of the cured coating film was visually judged.・ ・ ・: Good gloss. Δ: There is slight cloudiness. X: No gloss at all.

[0041]

Table 3 Example 3 Comparative Example 4 5 6 1 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate 85 85 69 85 Bisphenol A Diglycidyl ether 20 Obtained in Example 1 Sulfonium salt 3 Sulfonium salt obtained in Example 3 3 Sulfonium salt obtained in Example 3 3 UVI-6990 * 16 Titanium dioxide (rutile type) 98 98 98 98 Polyester resin * 2 10 10 6 10 Surfactant (L −7604) * 3 0.4 0.4 0.4 0.4 0.4 Curability ○ ○ ○ × Gloss ○ ○ ○ ×

Note) * 1 UVI-6990: manufactured by Union Carbide Co., Ltd., cationic photopolymerization initiator, 50% propylene carbonate diluted product. This is a mixture of the following two compounds

[0043]

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* 2 Polyester resin: “Byron 220” manufactured by Toyobo Co., Ltd. Molecular weight: 2,000 to 3,000. * 3 L-7604: manufactured by Nippon Unicar, a surfactant.

As is clear from the results in Table 2, the composition of the present invention has excellent curability, and the cured product has excellent gloss and the like.

[0046]

The energy ray-curable composition containing the photopolymerization initiator of the present invention has good compatibility and storage stability, and is excellent in curability, especially in a composition containing a pigment, and has high gloss and the like. Gives an excellent cured product.

Claims (5)

[Claims] 1. A photosensitive sulfonium salt having a phenothiazine structure in the molecule. 2. The following general formula (1): ## STR1 ## Ｘwhere X is the formula (2) (Wherein, R _{9 to} R ₁₈ are a hydrogen atom, a halogen atom, a nitro group, an alkoxy group which may have a substituent or an alkyl group which may have a substituent, respectively) And R _{1 to} R ₈ each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, -COOR (R
Hydrocarbon group) having 1 to 4 carbon atoms, - CY ₃ (Y represents a group represented by halogen atom) or the formula (2), it may be heterologous, and each of the same. Z is a compound represented by the following formula: MQ _Pm (OH) _m (3) (wherein, M is a phosphorus atom, an arsenic atom, or an antimony atom, Q is a halogen atom, and P is an integer of 4 to 6) , M is 0 or 1.) or BY _a R _b (4) (wherein B is a boron atom, a and b are integers from 0 to 4, where a + b is 4) Y represents a halogen atom or a hydroxyl group, and R represents a phenyl group substituted with at least one electron-withdrawing group or at least two halogen atoms.), And n is 1 or 2. Sulfonium salt represented by｝ 3. A photopolymerization initiator (B) comprising the sulfonium salt according to claim 1 or 2. 4. An energy ray-curable composition comprising a cationically polymerizable substance (A) and the photopolymerization initiator (B) according to claim 3. 5. A cured product of the energy ray-curable composition according to claim 4.