JPH06100611A - Photopolymerization initiator - Google Patents

Abstract

PURPOSE:To obtain the initiator which rapidly decomposes upon exposure to visible light to generate a free radical or cation and is highly stable by constitut ing it of a specific diaryliodonium salt. CONSTITUTION:The initiator comprises a diaryliodonium salt represented by the formula (wherein R is a lower alkyl; X is H, phenyl, an acyl, cyano, an ammonio group, or an alkoxycarbonyl; Y is an acyl, cyano, an ammonio group, or an alkoxycarbonyl; and n is 0 or 1).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photopolymerization initiator for radical polymerization and cationic polymerization. More specifically, it is a diaryl iodonium which decomposes with high sensitivity in the visible light region to generate a radical or a cation. It is about salt.

[0002]

2. Description of the Related Art Photocuring (negative type) based on photopolymerization
Many studies have been conducted to increase the photosensitivity rate of resins, but most of them are related to photopolymerization initiators having sensitivity in the ultraviolet region.

On the other hand, the photopolymerization initiator is used in addition to photoresist materials, inks, paints, varnishes, printing plate-making materials, etc.
It has been attracting attention as an image forming material using a laser beam and a light-sensitive material replacing silver salt, but such a light-sensitive property as a material for visible light is very insufficient in the conventional one. Therefore, it is necessary to expand the photosensitive wavelength region and dramatically increase the photosensitive speed. In this case, it goes without saying that the photosensitive resin composition must have both high resolution, which is an excellent characteristic when used as a photosensitive resin composition, and various physical properties suitable for the purpose.

Several proposals have been made as an initiator for generating radicals or cations in the visible light region. In JP 54-155292 A, imidazole 2
A combination of a monomer with an acridine derivative or an aryl ketone also uses an onium salt such as a diphenyliodonium salt as a radical generator, which is disclosed in JP-A-60-767.
40, JP-A-966044, Rhodanine derivatives, JP-A-60-78443, unsaturated ketones, JP-A-60-88005, 3-ketocoumarins, and JP-A-60-92302. Shows a complex initiator spectrally sensitized with a compound having a dialkylamino group. However, although these sensitivities are relatively high at several mJ / cm ^2, it cannot be said that they have good sensitivities, and there is a strong demand for photopolymerization initiators having higher sensitivity and higher stability.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for studying a sensitized decomposition reaction of a diaryliodonium salt which generates a radical or a cation by photolysis.
It was found that the counterion has visible light absorption to cause sensitized decomposition remarkably efficiently, and the finding was made for the purpose of obtaining a photopolymerization initiator having higher sensitivity.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and is represented by the general formula (I)

[0007]

[Chemical 2]

(Wherein R represents a lower alkyl group, X represents a residue selected from a hydrogen atom, a phenyl group, an acyl group, a cyano group, an ammonio group or an alkoxycarbonyl group, and Y represents an acyl group or a cyano group. A residue selected from a group, an ammonio group or an alkoxycarbonyl group, and n is 0
Or 1), which is a diaryl iodonium salt.

The present invention will be described in more detail below.

The diaryliodonium cation represented by the general formula (I) has a property of generating an acid upon irradiation with light. Examples of the compound used in the present invention include Macr
omolecules, 10, 1307 (1977).
Examples thereof include diphenyliodonium, ditolyliodonium, (p-anisyl) phenyliodonium, bis (m-nitrophenyl) iodonium, and bis (p-tert-butylphenyl) iodonium cation.

The sulfonium anion represented by the general formula (I) has a function of spectrally sensitizing the photolysis of the diaryliodonium salt. The following compounds can be illustrated as a sulfonium anion represented by general formula (I).

[0012]

[Chemical 3]

The photopolymerization initiator of the present invention can photopolymerize almost all polymerizable unsaturated compounds and compounds having a ring-opening polymerizable heterocycle with visible light in an extremely short time. Examples of these unsaturated compounds include unsaturated acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid and its anhydride, phthalic acid and its anhydride, fumaric acid, and methyl (meth) acrylate, (meth) Ethyl acrylate, butyl (meth) acrylate, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate,
Tetrahydropyranyl (meth) acrylate, dimethyl maleate, diethyl maleate, dimethyl fumarate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di ( There are unsaturated esters such as (meth) acrylates, and styrene, acrylamide, acrylonitrile, n-vinylpyrrolidone, vinyl acetate, various unsaturated polyesters, unsaturated polyethers, unsaturated polyurethanes and epoxy (meth) acrylate compounds. Examples of the ring-opening polymerizable compound include ethylene oxide, phenyl glycidyl ether, styrene oxide, glycidyl (meth) acrylate, epoxy resin, lactone, lactam, and ring. Sulfide, a compound such as cyclic imine.

The photopolymerization initiator of the present invention is added to these unsaturated compounds or heterocyclic compounds alone or as a mixture of two or more kinds, and if necessary, additives, inhibitors, carriers and the like are added in a suitable diluting solvent. Dissolve it into a photopolymerizable composition.

The amount of the photopolymerization initiator added is 0.1 to 30 parts by weight, preferably 0.5 to 20 parts by weight, based on 100 parts by weight of the unsaturated compound or the heterocyclic compound.

The photopolymerizable composition thus obtained can be subjected to a polymerization reaction in an extremely short time by irradiating it with an actinic ray in the visible light wavelength range of 400 to 550 nm.
As a light source suitable for the photopolymerization initiator of the present invention, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a high pressure xenon lamp, a halogen lamp, a helium-cadmium laser, and an argon laser can be used.

[0017]

The photopolymerization initiator of the present invention is remarkably efficiently increased by allowing a counter ion to absorb visible light in the process of examining the sensitized decomposition reaction of a diaryl iodonium salt which generates a radical or a cation by photolysis. Since it causes sensitization, it has higher sensitivity in the visible light range than conventional photopolymerization initiators.

[0018]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. Parts in the examples indicate parts by weight.

6.38 g (0.05 mol) of sodium sulfite was dissolved in 30 ml of water, and 10.00 g of p- (N, N-chloroethylmethylamino) benzaldehyde was added.
(0.05 mol) was added, and the mixture was heated under reflux for about 12 hours. The reaction solution was washed with chloroform and then sodium chloride was added to obtain 7.93 g (59%) of a sulfonium salt (formula II).

[0020]

[Chemical 4]

4.34 g of benzoylacetonitrile
(0.03 mol) was dissolved in 40 ml of chloroform, and then 7.93 g (0.03 g) of the sulfonium salt (formula II).
Mol) was added, about 1 ml of piperidine was added dropwise with stirring, and the mixture was refluxed for 4 hours. The reaction product was filtered off, washed with chloroform several times, and then dried to obtain 8.25 g (70%) of a dye (formula III).

[0022]

[Chemical 5]

Diphenyliodonium hexafluorophosphate 8.6 dissolved in 50 ml of methylene chloride
8.00 g of the dye (formula III) in 9 g (0.02 mol)
A solution of (0.02 mol) in 20 ml of water was added dropwise, and the mixture was stirred at room temperature for 2 hours. The aqueous layer extracted with methylene chloride was combined with the organic layer, dried over magnesium sulfate, and concentrated to obtain a photopolymerization initiator (formula IV).
The photopolymerization initiator was purified by silica gel column chromatography (mobile layer: THF / methanol mixed system) (yield: 7.20 g, 58%).

[0024]

[Chemical 6]

Poly (methyl methacrylate / ethyl acrylate / methacrylic acid) (molar ratio 5/4/1, molecular weight 10
10,000 parts) and 100 parts of the monomers shown in Table 1, the photopolymerization initiator was added at the ratio shown in Table 1, and 1 part thereof was added.
A photosensitive solution was obtained by uniformly dissolving it in 000 parts of diethylene glycol dimethyl ether.

These photosensitive solutions were spin-coated on an anodized aluminum plate so that the photosensitive layer was about 2 μm, and dried to obtain a photosensitive plate. This photosensitive plate was masked with a gray scale (Kodak step tablet No. 2),
After exposure using a 500 W xenon lamp (using Toshiba color glass filter Y-47 and interference filter KL-49), a commercially available alkaline developer (D, manufactured by Fuji Photo Film Co., Ltd.
N-3C) was developed and the sensitivity was measured by reading the number of gray scale steps in the cured area. The results are shown in Table 1.

[0027]

[Table 1]

Comparative Examples 1 to 3 Photosensitization was carried out in the same manner as in Example 1 except that 4 parts of diphenyliodonium hexafluorophosphate and 4 parts of sensitizing dye were used instead of the photopolymerization initiator in Example 1. A plate was prepared and the sensitivity was measured in the same manner. The results are shown in Table 2.

[0029]

[Table 2]

[0030]

INDUSTRIAL APPLICABILITY The photopolymerization initiator of the present invention is remarkably efficient by allowing a counter ion to absorb visible light in the process of examining the sensitized decomposition reaction of a diaryliodonium salt which generates a radical or a cation by photolysis. Since it often causes sensitized decomposition, it has higher sensitivity in the visible light region than conventional photopolymerization initiators.

Therefore, it can be applied to a wide variety of fields such as plate-making materials for planographic printing and letterpress, various reliefs, holograms and the like.

Claims (1)

[Claims] 1. A compound represented by the general formula (I): (In the formula, R represents a lower alkyl group, X is a residue selected from a hydrogen atom, a phenyl group, an acyl group, a cyano group, an ammonio group or an alkoxycarbonyl group, and Y is an acyl group, a cyano group, an ammonio. Group or a residue selected from an alkoxycarbonyl group, and n is 0 or 1), which is a diaryl iodonium salt.