JPH04106548A - Photopolymerizable composition - Google Patents

Abstract

PURPOSE:To obtain a photopolymn. initiator system which has high sensitivity for light of long wavelength region and excellent dissolution stability by using a specified squarylium dye for the polymn. initiator system for the photopolymerizable compsn. comprising an ethylene-type unsatd. compd. which can cause addition polymn. and the photopolymn. initiator. CONSTITUTION:The polymerizable compd. for addition polymn. to be incorporated as the first essential compsn. having at least one ethylene-type unsatd. double bond is a compd. which causes addition polymn. and is hardened when the compsn. is irradiated with active way. The addition polymn. is effected by the photopolymn. initiator system as the second essential component. The photopolymn. initiator system as the second essential component consists of a combination of two components. The first one (a) is a squarylium dye expressed by the formula, wherein R1 and R2 are alkyl or aryl groups each of which may have substd. groups and ring A and ring B are benzene rings or naphthalene rings which may have substd. groups. The second component (b) is a s-triazine deriv. having at least one of mono, di or tri halogen-substd. methyl group coupled to the s-triazine ring.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to photopolymerizable compositions.

In particular, it relates to improved photopolymerizable compositions that exhibit high sensitivity to light in the long wavelength region.

[Conventional technology]

Conventionally, many image forming methods using photopolymerization systems are known. For example, a photopolymerizable composition consisting of a compound containing an ethylenic double bond capable of addition polymerization, a photopolymerization initiator, and an organic polymer binder used if desired is prepared, and this photopolymerizable composition is supported. A photosensitive material is prepared by applying a layer of a photopolymerizable composition onto the body, image-wise exposing the desired image, polymerizing and curing the exposed areas, and dissolving and removing the unexposed areas to form a cured relief image. A method of forming an image by inducing a change in adhesive strength due to light and then peeling off the support, and other methods of creating an image using a change in toner adhesion resistance of a photopolymerizable composition layer due to light. etc. Conventionally, benzoin, benzoin alkyl ether, benzyl ketal, benzophenone, anthraquinone, benzyl, Michler's ketone, and the like have been used as photopolymerization initiators for photopolymerizable compositions applied to these methods.

These photopolymerization initiators had a function of being sensitive to short wavelength light mainly in the ultraviolet region of 400 nm or less.

In recent years, with the development of image forming technology, there has been a strong demand for photopolymers that are highly sensitive to light in the visible region.For example, argon ion laser 4
A laser engraving method using an 88 nm oscillation beam is considered to be one of the promising techniques in the future, and in response to this, many photopolymerization initiation systems with a sensitivity range extended to around 500 nm have been proposed. Furthermore, recently, 600n
Research on photoinitiation systems that are compatible with long-wavelength light exceeding (2) has become active. One of these applied technologies is laser plate making using He-Ne laser or semiconductor laser.
The other is a full-color image reproduction technology using a photopolymerization system.

Regarding the latter, it was previously described in the specification of Japanese Patent Publication No. 46-41346, and according to the specification, a droplet-shaped product containing each photopolymerization initiator and color coupler corresponding to blue, green, and red light. Three layers of photopolymerizable compositions each dispersed in a gelatin film are applied to form a photosensitive layer. The patent discloses a technique in which the uncured portions are then irradiated with color image light and treated with a color developing solution to develop color and a full color image is obtained. Further, an applied technique combining this idea with a pressure-sensitive coloring method using microcapsules has been proposed. For example, the description can be found in Japanese Patent Application Laid-open No. 143044/1983. According to the specification, a photopolymerizable composition containing a photopolymerization initiator sensitive to each of the three color rays and each leuco dye is filled into microcapsules and applied onto a sheet. After exposing this to color image light, the uncured portions of the capsules are pressure-broken and transferred onto a color-forming sheet to promote the development of yellow, magenta, and cyan colors to obtain a full-color image.

[Problem to be solved by the invention]

One of the challenges required in the laser engraving and full-color image reproduction techniques described above is the long wavelength, especially 600n-
This is an improvement in the sensitivity of the sensitive material to light rays in the region exceeding
Furthermore, dissolution stability in photo-initiated sensitive materials and appropriate spectral sensitivity are required, especially in full-color reproduction technology. We previously proposed a photoinitiation system consisting of a combination of squarylium dye and a specific triazine compound, but its solubility stability and spectral sensitivity characteristics were not necessarily sufficient.The present invention solves these problems. Improvements to be made (This was made as a result of repeated studies. Therefore, the purpose of the present invention is to
The object of the present invention is to provide a photoinitiation system that is highly sensitive to long wavelength light, particularly in the 600 to 700 n- region, has excellent dissolution stability, and has good spectral sensitivity characteristics.

[Means to solve problems]

The inventors have discovered that these problems can be solved by a system that combines a squarylium dye with a specific structure and an s-) lyazine compound.

That is, the gist of the present invention is to provide a photopolymerizable composition comprising an ethylenically unsaturated compound capable of addition polymerization and a photopolymerization initiation system, wherein (a) the photopolymerization initiation system has the following general formula [I ] A squarylium dye represented by [wherein RI and Rt each represent an optionally substituent alkyl group or aryl group, and Ring A and Ring B represent a benzene ring or naphthalene ring that optionally have a substituent, ] and (c) s having at least one halogenated methyl group
-) A photopolymerizable composition comprising a riazine compound.

The present invention will be explained in detail below.

The addition-polymerizable compound (hereinafter abbreviated as "ethylenic compound") having at least one ethylenically unsaturated double bond contained as the first essential component in the photopolymerizable composition of the present invention means: It is a compound having ethylenically unsaturated double bonds that undergoes addition polymerization and hardening due to the action of the photopolymerization initiation system, which is the second essential component, when the photopolymerizable composite acid is irradiated with actinic rays. For example, it is a monomer having the above-mentioned double bond, or a polymer having an ethylenically unsaturated double bond in the side chain or main chain.In addition, the monomer in the present invention means: It is a concept that is opposed to so-called polymeric substances, and therefore includes dimers, trimers, and oligomers in addition to monomers in the narrow sense.

Examples of monomers containing ethylenically unsaturated bonds include unsaturated carboxylic acids, esters of these with monohydroxy compounds, esters of aliphatic polyhydroxy compounds with unsaturated carboxylic acids, and aromatic polyhydroxy compounds with unsaturated carboxylic acids. and esters obtained by esterification reactions between unsaturated carboxylic acids, polyhydric carboxylic acids, and polyhydric hydroxy compounds such as the aforementioned aliphatic polyhydroxy compounds and aromatic polyhydroxy compounds.

The ester of the aliphatic polyhydroxy compound and unsaturated carboxylic acid is not limited, but specific examples include ethylene glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and pentaerythritol. Acrylic acid esters such as diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, glycerol acrylate, and methacrylates are substituted for the acrylates of these exemplary compounds. Examples include methacrylic esters, itaconic esters in place of itaconate, crotonic esters in place of crotonate, and maleic esters in place of maleate.

Examples of esters of aromatic polyhydroxy compounds and unsaturated carboxylic acids include hydroquinone diacrylate, hydroquinone dimethacrylate, resorcin diacrylate, resorcin dimethacrylate, and pyrogallol triacrylate.

Esters obtained by the esterification reaction of unsaturated carboxylic acids with polyhydric carboxylic acids and polyhydric hydroxy compounds are not necessarily single, but typical examples include acrylic acid, phthalic acid, and ethylene glycol. Condensates of acrylic acid, maleic acid and diethylene glycol, condensates of methacrylic acid, terephthalic acid and pentaerythritol, condensates of acrylic acid, adipic acid, butanediol and glycerin, and the like.

Examples of ethylenic compounds used in the invention include acrylamides such as ethylenebisacrylamide;
Allyl esters such as diallyl phthalate; vinyl group-containing compounds such as divinyl phthalate are useful.

The aforementioned polymers having an ethylenically unsaturated bond in the main chain include, for example, polyesters obtained by a polycondensation reaction between an unsaturated dicarboxylic acid and a dihydroxy compound, and polycondensation reactions between an unsaturated dicarboxylic acid and a diamine. There are polyamides obtained by.

Polymers having ethylenically unsaturated bonds in their side chains include condensation polymers of dicarboxylic acids having unsaturated bonds in their side chains, such as itaconic acid, propylidene succinic acid, ethylidene malonic acid, etc., and dihydroxy or diamine compounds. . In addition, polymers having reactive functional groups such as hydroxy groups or halogenated methyl groups in their side chains, such as polyvinyl alcohol, poly(2-hydroxyethyl methacrylate),
Polymers obtained by polymer reaction of polyepichlorohydrin or the like with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, or crotonic acid may also be suitably used.

Among the ethylenic compounds described above, acrylic ester or methacrylic ester monomers can be particularly preferably used.

Next, the photopolymerization initiation system, which is the second essential component of the photopolymerizable composition of the present invention, will be explained. The photopolymerization initiation system of the present invention is composed of a combination of two components, and the first Component (a) is a squarylium dye represented by the following general formula [■].

[In the formula, Rr and Rz are an alkyl group or an aryl group which may have a substituent, and Ring A1 and Ring B each represent a benzene ring or a naphthalene ring which may have a substituent. ] Conventionally, few squarylium dyes have sufficient solubility in the photosensitive layer and tend to precipitate easily, resulting in the disadvantage that stable photosensitive characteristics are difficult to obtain. In addition, many squarylium pigments are 600nn
Since it can be used as a sensitizer for light rays of + to 700 nm, that is, red light, it can be used as a red-sensitive material for full-color image reproduction, but its spectral sensitivity characteristics have not always been sufficient.

This tendency is particularly noticeable in red-sensitive materials that are compatible with long wavelengths, and the reason for this is that they are thickly streaked toward the undesired short wavelength side. For example, in the case of red-sensitive material, 50
Undesirable light sensitivity occurs in the 0-600 nm region, resulting in poor color reproducibility. As a parameter for evaluating this spectral sensitivity characteristic, in the case of a red-sensitive material, it can be evaluated by the ratio of 550 nn of the corresponding sensitivity to 650 nm + the corresponding sensitivity δ. That is, it means that the larger the value of this ratio, the better the spectral sensitivity characteristics and the better the color reproducibility. Hereinafter, this value will be abbreviated as a spectral sensitivity value.

Although it has been difficult for conventional squarylium dyes to satisfy both the above-mentioned dissolution stability and spectral sensitivity characteristics, we have found that the dye of general formula (1) above has good characteristics. .

R1 and R2 in the above general formula are preferably a methyl group, ethyl group, n-propyl group, n-butyl group, n-hexyl group, n-octyl group as an alkyl group, and phenyl group as an aryl group. group, naphthyl group. These may further have a substituent, and the substituent used is preferably a phenyl group, a phenoxy group, a methoxy group, or an ethoxy group.

Ring A1 Ring B is a benzene ring or a naphthalene ring which may have a substituent, and preferred substituents include an alkyl group such as a methyl group or an ethyl group; an alkoxy group such as a methoxy or ethoxy group; chlorine or bromine. A halogen atom such as is preferred.

Suitable examples of squarylium satisfying such conditions include the following compounds. []
The symbol inside is the abbreviation of the compound.

0-C2H5 The above-exemplified squarylium dyes used in the present invention can be prepared according to conventional methods, for example, H3E, Sprenger, Angew, Chem, 1nternat E.
dit 6 553 (1967).

Next, the second component 0) constituting the photopolymerization initiation system of the present invention
).

Component (b) is an S-triazine derivative in which at least one mono-, di-, or trihalogen-substituted methyl group is bonded to the s-1 riazine ring. These are, for example, written by Wakabayashi et al., Bu
ll, Chem, Soc, Japan, 42.2924
(1969), U.S. Pat. No. 3,987.037, F. Chaefer et al., J. O.
rg,Chem,.

29.1527 (1964). Specific examples of these compounds will be given below, and the characters in [ ] are abbreviations of the compounds used hereinafter. They are,
For example, 2,4.6-1-lis(trichloromethyl)-
s-) riazine (b-1), 2-methyl-4,6-bis(trichloromethyl) s-) riazine l'b-2), 2
-Phenyl-4゜6-bis(trichloromethyl)-S-
)Ryazine, 2-(p-chlorophenyl)-4,6-bis(trichloromethyl)-S-)Ryazine, 2-phenylthio-4,6-bis(trichloromethyl)-S-
Triazine (b-3L 2-benzylthio-4゜6-bis(trichloromethyl)-s-1 riazine, 2-(p-
tolyl)-4,6-bis(trichloromethyl)-S-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-8-triazine, 2-n-propyl-4,6- Bis(trichloromethyl)-S-triazine, 2-(α,α,β-trichloroethyl)-4,
6bis(trichloromethyl)-S-triazine, 2-styryl-4,6-bis(trichloromethyl)-8-triazine, 2,4.6-)lis(dichloromethyl)-s-
triazine, 2.4.6-)lis(tribromomethyl)
-S-triazine (b-4), 2-methyl-4,6-
Bis(tribromomethyl)-s-)riazine, 2,4.
6-1-lis(dibromethyl)-S-triazine and the like. Among these, particularly preferred are, for example, 2.4°6-tris(trichloromethyl)-S-) riazine, 2
-phenyl-4,6-bis(trichloromethyl)-s-
) riazine, 2-methyl-4,6-bis(trichloromethyl)-S-) riazine, 2-phenylthio-4,6-
Bis(trichloromethyl)-s-triazine, 2,4.
Examples include S triazines containing two or more trichlor or tribromomethyl groups, such as 6-)lis(tribromomethyl)-S-)riazine. These S-triazines can be synthesized by reacting the corresponding nitrile compound with aluminum bromide in the presence of hydrogen chloride, or via the corresponding imidate, according to the above-mentioned literature.

The photopolymerization initiation system of the present invention can only exhibit remarkable effects by combining the two components (a) and (b) described above, and the ratio of their use is preferably a weight ratio of (a):(b). , in the range from 1:30 to 10:1, particularly preferably 1
:15 to 4:1. Further, the total amount of the photopolymerization initiation system, that is, the components (a) and (b) contained in the photopolymerizable composition of the present invention is preferably 0.1% to 30% by weight relative to the ethylenic compound. %,
Particularly preferred is a range of 0.5% to 20%.

In addition to the above-mentioned components, the photopolymerizable composition of the present invention may further contain other substances depending on the intended use thereof.

For example, when film-forming ability or viscosity control ability is required, an organic polymer substance may be added as a binder. Specific examples include (meth)acrylic acid, esterified products thereof, maleic acid, acrylonitrile, styrene, vinyl acetate, vinylidene chloride, etc. alone or copolymers, polyethylene oxide, polyvinylpyrrolidone, polyamide, polyurethane. , polyethylene terephthalate isophthalate, acetyl cellulose or polyvinyl butyral. These binders are preferably used in a weight ratio of 5 to the ethylenic compound.
It can be added and mixed in a range of 00% or less, particularly preferably 200% or less.

Others: hydroquinone, P-methoxyphenol, 2
, 6-di-t-butyl-P-cresol; colorants consisting of organic or inorganic dyes and pigments; dioctyl phthalate, didodecyl phthalate, tricresyl phosphate, dioctyl adipate, triethylene glycol caprylate Additives such as plasticizers such as tertiary amines and sensitivity improvers such as thiols can also be added.

When the present composition is applied to color image reproduction techniques, dye precursors, such as color forming materials such as those used in conventional color photographic films as described in Japanese Patent Publication No. 46-41346, or A leuco dye well known in the technical field of pressure-sensitive dyes can be added. Examples of leuco pigments include triarylmethane, bisarylmethane, xanthine compounds, fluoran, thiazine compounds, and their partial skeletons such as lactones, lactams,
Compounds having a sultone, spiropyran structure, etc. are included.

Preferred addition amounts of the various additives mentioned above are, in terms of weight ratio to the solid content of the photopolymerizable composition, thermal polymerization inhibitor 2% or less, colorant 20% or less, plasticizer 40% or less, and dye precursor 4%.
It is in the range of 0% or less.

The form of the photosensitive material produced using the present composition can be appropriately selected depending on the purpose of use.

For example, it can be applied without a solvent or diluted with an appropriate solvent to a sheet, such as a polymer sheet, paper, or metal sheet, dried, and if necessary, an overcoat layer for oxygen blocking is further provided on the upper layer. Various options are possible, such as a multilayer coating of a plurality of types of sensitive materials dispersed in small droplets in a medium, and a coating of the composition encapsulated in microcapsules on a sheet.

Exposure light sources applicable to the composition of the present invention are not particularly limited, but include, for example, carbon arc, high-pressure mercury lamp, xenon lamp, metal halide lamp, fluorescent lamp, tungsten lamp, halogen lamp, helium neon laser-1 semiconductor laser, etc. A light source containing the above visible light rays can be particularly preferably used.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded.

The abbreviations of squarylium dye and S-) liazine used in Examples and Comparative Examples correspond to those exemplified in the specification and the compounds below.

R8 R1 Examples 1 to 8 and Comparative Examples 1 to 4 The evaluation items of dissolution stability and spectral sensitivity values each represent the evaluation results obtained according to the following methods.

Dissolution stability This item evaluates the degree of stable solubility. 1% by weight of squarylium dye and 5% by weight of S-) riazine compound were added to pentaerythritol triacrylate, and after dissolving with heating, the mixture was allowed to stand in a room. - If no precipitation of the additive is observed after being left for several months, it is considered "good".
A case in which a slight amount of crystallization was observed was rated as "fairly good", and a case in which significant crystallization was rated as "poor".

Spectral sensitivity value This item evaluates and measures red light spectral sensitivity characteristics. Methyl methacrylate/methacrylic acid copolymer (weight average molecular weight 45,000, copolymerization ratio 85/12) 2 g
, 8 g of pentaerythritol triacrylate was dissolved in 120 g of methyl ethyl ketone to prepare a photosensitive liquid stock solution. A portion of this stock solution was taken, and the squarylium dye 1% by weight (based on solid content) listed in Table 1 and s-) riazine 5 were added.
A sample photosensitive solution was prepared by adding % by weight (based on solid content).

Each photosensitive solution obtained was placed on a grained and anodized aluminum sheet using a whirler to form a dry film with a dry film thickness of 1.6 μm.
The mixture was applied to a piece of Japanese zelkova, and then dried at 70°C for 13 minutes.

Further apply a polyvinyl alcohol aqueous solution to the surface,
A photosensitive material sample was prepared by providing an overcoat layer with a dry thickness of 3 μm. Next, these samples were exposed to a spectroscopic irradiation device (
After exposure for a certain period of time using "'RM-23-1" (manufactured by Narumi Co., Ltd.), development was performed with a developer (an aqueous solution containing 9% by weight of butyl cellosolve and 1% by weight of sodium silicate), and the photocuring rate for each wavelength was I asked for The spectral sensitivity values here are for red light, i.e. 650n
This value is calculated as the ratio of the photocuring speed corresponding to the 550n beam to that corresponding to the 550n beam. This value indicates the magnitude when comparing the sensitivity for red light with the sensitivity that is lower on the shorter wavelength side, and the larger this value is, the better the spectral sensitivity is. It shows. As is clear from Table 1, the photoinitiation system of the present invention has both good solubility and spectral sensitivity characteristics.

Table 1 [Effects of the Invention] According to the present invention, a photopolymerizable composition can be obtained which exhibits particularly excellent sensitivity to light having a wavelength of 600 to 700 nm and also has excellent storage stability.

Claims (1)

[Claims] (1) A photopolymerizable composition comprising an ethylenically unsaturated compound capable of addition polymerization and a photopolymerization initiation system, in which the photopolymerization initiation system comprises (a) a squarylium dye represented by the following general formula [I], ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [I] [In the formula, R_1 and R_2 are each an alkyl group or an aryl group that may have a substituent, and Ring A and Ring B are each a benzene ring that may have a substituent. Or indicates a naphthalene ring. ]
and (b) s having at least one halogenated methyl group
- A photopolymerizable composition comprising a triazine compound.