JP2990830B2 - Photopolymerizable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photopolymerizable composition containing an improved photopolymerization initiation system, and more particularly to a photopolymerizable composition using a photopolymerization initiation system containing biimidazoles. .

[0002]

2. Description of the Related Art A large number of photopolymerization initiators or photopolymerization initiation systems have been developed and applied and put to practical use. All of these have been selected and adopted in consideration of the use, purpose and required performance. A biimidazole-based initiation system is generally used as a useful initiation system component because good sensitivity characteristics can be obtained in combination with a specific sensitizer.

However, the stability of a photopolymerizable material during storage is usually not always sufficient, and the tendency is particularly remarkable as the sensitivity is increased. In recent years, high-sensitivity photosensitive materials using photopolymerizable photosensitive materials have been studied in various application fields. Among them, there is a laser direct plate making as a system which is expected to be practically used practically, and a highly sensitive photopolymer system corresponding to a laser oscillation wavelength, for example, an argon laser of 488 nm is strongly demanded.
Photopolymerizable light-sensitive materials containing biimidazole are also considered to be one of useful materials that can respond to them, but their stability has not always been satisfactory.

[0004] The present inventors have assiduously studied and, as a result, have found that by adding and blending a specific compound in a composition, the composition can have both high sensitivity characteristics and stability, and arrived at the present invention. . That is, an object of the present invention is to provide a photopolymerizable composition containing a photopolymerization initiation system having particularly excellent stability over time while maintaining high sensitivity characteristics. Such objects of the invention can be achieved by a photopolymerizable composition comprising a polymerizable ethylenically unsaturated monomer, a hexaarylbiimidazole, a sensitizer, and a dialkylaminoaryl aldehyde.

Further, the composition preferably contains a heterocyclic thiol, and / or a hexaarylbiimidazole having a specific substituent is preferably used. Hereinafter, the present invention will be described in more detail. First, the polymerizable ethylenically unsaturated monomer used in the present invention is not particularly limited as long as it exhibits a chain polymerization reaction with an active free radical. The meaning of the monomer is a concept corresponding to a so-called polymer substance, and therefore includes not only a monomer in a narrow sense but also a dimer, a trimer, and an oligomer.

The polymerizable ethylenically unsaturated monomers include, for example, unsaturated carboxylic acids, esters of aliphatic polyhydroxy compounds and unsaturated carboxylic acids, and esters of aromatic polyhydroxy compounds and unsaturated carboxylic acids. ester;
Esters obtained by an esterification reaction of an unsaturated carboxylic acid with a polyvalent carboxylic acid and the above-mentioned polyvalent hydroxy compound such as the aliphatic polyhydroxy compound and the aromatic polyhydroxy compound are exemplified.

Specific examples of the ester of the aliphatic polyhydroxy compound with an unsaturated carboxylic acid include ethylene glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and pentaerythritol diacrylate. Acrylates such as pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, glycerol acrylate, and methacrylates in which the acrylate of these exemplified compounds is replaced with methacrylate Similarly, itaconic acid esters and crotonates were substituted for itaconates. And there is a maleic acid ester or the like in place of crotonic acid ester or maleate.

Examples of the ester of an aromatic polyhydroxy compound and an unsaturated carboxylic acid include hydroquinone diacrylate, hydroquinone dimethacrylate, resorcin diacrylate, resorcin dimethacrylate, pyrocarol triacrylate and the like. The ester obtained by the esterification reaction of the unsaturated carboxylic acid with the polycarboxylic acid and the polyhydroxy compound is not necessarily a single substance, but typical examples include acrylic acid, phthalic acid, and ethylene glycol. Condensates of acrylic acid, maleic acid and ethylene glycol, condensates of methacrylic acid, terephthalic acid and pentaerythritol, condensates of acrylic acid, adipic acid, butanediol and glycerin.

Other examples of the ethylenically unsaturated monomer used in the present invention include urethane acrylates such as an addition reaction product of toluene diisocyanate and hydroxyethyl acrylate; an addition reaction product of a diepoxy compound and hydroxyethyl acrylate Epoxy acrylates; acrylamides such as ethylene bisacrylamide; allyl esters such as diallyl phthalate; and vinyl group-containing compounds such as divinyl phthalate.

[0010] Of these, acrylate or methacrylate monomers are particularly useful. Next, the hexaarylbiimidazole of the present invention will be described. this is,
It is also called a 2,4,5-triarylimidazolyl dimer and is a compound having a structure of the following general formula in which two imidazoles are connected by one covalent bond.

[0011]

Embedded image In the present invention, various isomers of the above compounds having different bonding systems can be used. A in the above general formula
r ₁ is an aryl group having a halogen substituent at the o-position, particularly preferably an o-chlorophenyl or o-bromophenyl group.

Specific examples of suitable biimidazoles include, for example, 2,2'-bis (o-chlorophenyl)-
4,4 ′, 5,5′-tetraphenylbiimidazole,
2,2′-bis (o-bromophenyl) -4,4 ′,
5,5′-tetraphenylbiimidazole, 2,2′-
Bis (o, p-dichlorophenyl) -4,4 ', 5
5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (m-methoxyphenyl) biimidazole, 2,2′-
Bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p-carbethoxyphenyl) biimidazole,
2,2′-bis (o-bromophenyl) -4,4 ′,
5,5′-tetra (p-carbethoxyphenyl) biimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetra (p-carbobenzyloxyphenyl) ) Biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p-carbo-n-propyloxyphenyl) biimidazole, 2,2′-bis (o -Chlorophenyl) -4,
4 ', 5,5'-tetra (p-carbophenoxyphenyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (p-chlorophenyl) bi Imidazole, 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (o, p-dichlorophenyl) biimidazole, 2,2'-bis (o-
Bromophenyl) -4,4 ', 5,5'-tetra (o,
p-Dichlorophenyl) biimidazole, 2,2′-bis (o-chromephenyl) -4,4 ′, 5,5′-tetra (p-bromophenyl) biimidazole and the like.

Of these, those in which Ar ₂ or Ar ₃ in the above general formula is an aryl group having a carboalkoxy group or an aryl group substituted with a halogen atom are more preferred. These biimidazoles can be used in combination with other kinds of biimidazoles, if necessary. Biimidazoles are, for example, Bull.Chem.Soc.Japa
n, 33 , 565 (1960) and J.org. Chem., 36 [16] 2262 (1971).

Next, the sensitizer of the present invention will be described.
The sensitizer in the present invention means a compound capable of effectively generating an active radical upon irradiation with light when coexisting with the above-mentioned biimidazoles. Examples of typical enhancers include, for example, triphenylmethane leuco dyes such as leuco crystal violet and leucomalachite green as disclosed in U.S. Pat.No. 3,479,185, and erythrosine and eosin Y. Photoreducing dyes,
U.S. Patent 3,549,367, U.S. Patent 3,652,275
Aminophenyl ketones such as Michler's ketone and aminostyryl ketone disclosed in US Pat. No. 3,844,790, β-diketones shown in U.S. Pat.No. 3,844,790, indanones found in U.S. Pat.
Ketocoumarins disclosed in JP-A-52-112681, aminostyrene derivatives and aminophenylbutadiene derivatives disclosed in JP-A-59-56403, U.S. Pat.
Aminophenyl heterocycles found in US Pat.
Examples include julolidyl heterocycles described in U.S. Pat. No. 4,966,830.

Next, the dialkylaminoaryl aldehyde will be described. Stability can be improved by incorporating this compound into the composition. The aldehyde may have other substituents, for example, an alkyl group, an alkoxy group, a halogen atom, a cyano group, a phenyl group and the like. Specific examples of the aldehyde include 4-dimethylaminobenzaldehyde, 4-diethylaminobenzaldehyde, 4-dibenzylaminobenzaldehyde, 9-julolidylaldehyde, 4-dimethylaminonaphthaldehyde-1,4-diethylamino-3-chlorobenzaldehyde , 4-dimethylamino-3-methoxybenzaldehyde and the like.

Next, the heterocyclic thiol will be described. The compounds often provide significant stabilizing and sensitivity improving effects. The heterocycle is preferably a nitrogen-containing heterocycle. Specific examples of the present thiol include 2-mercaptobenzthiazole, 2-mercapto-6-ethoxybenzthiazole,
2-mercapto-6-chlorobenzthiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 3-mercapto-4-methyl-1,2,4
-Triazole, 2-mercapto-4 (3H) -quinazolinone and the like.

The main constituents of the photopolymerizable composition of the present invention have been described in detail above. A preferred ratio thereof is that hexaarylbiene is used per 100 parts by weight of the polymerizable ethylenically unsaturated monomer. Imidazole is preferably 0.1
To 80 parts by weight, particularly preferably 0.5 to 50 parts by weight, a sensitizer is preferably 0.01 to 20 parts by weight, particularly preferably 0.05 to 10 parts by weight, and a dialkylaminoaryl aldehyde is preferably 0.1 to 10 parts by weight. It is in the range of 1 to 30 parts by weight, particularly preferably 0.5 to 20 parts by weight. The optionally added heterocyclic thiol is preferably in the range up to 60 parts by weight, particularly preferably up to 40 parts by weight.

The photopolymerizable composition of the present invention may further contain, in addition to the above-mentioned components, other substances according to the purpose of use. For example, when a film-forming ability or a viscosity adjusting ability is required, an organic polymer substance may be added as a binder. Specific examples thereof include, for example, (meth) acrylic acid, their esterified products, maleic acid,
Examples thereof include homo- or copolymers such as acrylonitrile, styrene, vinyl acetate, and vinylidene chloride; and polyethylene oxide, polyvinyl pyrrolidone, polyamide, polyurethane, polyethylene terephthalate isophthalate, acetyl cellulose, and polyvinyl butyral. These binders can be added and mixed preferably in an amount of 400 parts by weight or less, particularly preferably 200 parts by weight or less, based on 100 parts by weight of the ethylenically unsaturated monomer.

Thermal polymerization inhibitors such as hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol; coloring agents comprising organic or inorganic dyes and pigments; dioctyl phthalate, didodecyl phthalate,
Plasticizers such as tricresyl phosphate, dioctyl adipate, and triethylene glycol dicaprylate, and other additives such as dye precursors can also be added.

Preferred amounts of the various additives described above are 2 parts by weight or less of the thermal polymerization inhibitor, 20 parts by weight or less of the colorant, and 40 parts by weight or less of the plasticizer per 100 parts by weight of the unsaturated monomer.
The range is 30 parts by weight or less of the dye precursor. The form of the photosensitive material produced by using the present composition can be appropriately selected according to the purpose of use. For example, a solvent-free or diluted with an appropriate solvent, applied onto a sheet, for example, a polymer sheet, paper, or a metal sheet, dried and, if necessary, an overcoat layer or a polymer sheet layer for blocking oxygen is further formed on the upper layer. Various forms such as a form provided, a form in which the present composition is encapsulated in microcapsules and applied on a sheet, and a form in which a liquid photosensitive resin is used as it is can be selected.

The exposure light source applicable to the composition of the present invention is not particularly limited. Examples thereof include a carbon arc, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a halogen lamp, a helium cadmium laser, and an argon ion A laser, a helium neon laser or the like can be particularly preferably used.

[0022]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples unless it exceeds the gist thereof. “Sensitivity change rate” used in Examples and Comparative Examples indicates a value calculated by the following equation.

[0023]

(Equation 1) The closer the value is to 1, the smaller the change, and the closer the value is to 0, the more remarkable the decrease in sensitivity. Further, the abbreviations of biimidazole and sensitizer used in Examples and Comparative Examples indicate compounds having the following structures.

<Bimidazole> In the aforementioned general formula [I],

[0025]

Embedded image In addition, [addition amount] indicates the addition weight% based on the total weight of the ethylenically unsaturated monomer and the binder. Example 1
4 and Comparative Examples 1-4 Methyl methacrylate / methacrylic acid copolymer (weight average molecular weight 45,000, copolymerization ratio 85/15) 3 g, trimethylolpropane triacrylate 7 g, sensitizer JT-1 100 mg and Victoria 60 mg of pure blue BOH was dissolved in 90 g of methyl ethyl ketone. This includes biimidazole and 2-mercaptobenzthiazole as shown in Table I, and
In some cases, p-diethylaminobenzaldehyde was added and dissolved in the respective amounts described. This photosensitive solution is applied on a grained and anodized aluminum sheet using a wheeler to a dry film thickness of 2 μm.
Dried for minutes. Further, an aqueous polyvinyl alcohol solution was applied to the surface, and an overcoat layer having a dry film thickness of 3 μm was provided. A portion of this photosensitive material sample was cut out and exposed using a diffraction spectral irradiation apparatus ("RM-23", manufactured by Narumi Co., Ltd.), and then developed with a developing solution containing 9% by weight of butyl cellosolve and 1% by weight of sodium silicate. And the amount of light energy required for photocuring with a light beam having a wavelength of 488 nm was determined and used as the initial sensitivity. On the other hand, another part of the photographic material was cut out and treated in an oven at 55 ° C. for 6 days, then the photocuring energy was obtained under the same conditions as above, and the sensitivity change rate was calculated.
The results are shown in Table I.

[0026]

[Table 1] Comparing the rate of change in sensitivity between each of the examples and the corresponding comparative example under conditions that differ only in the presence or absence of p-diethylaminobenzaldehyde, it is clear that the stability is improved by the addition of the aldehyde.

[0027]

Example 5 In Example 1, 5 g of the same copolymer, 5 g of trimethylolpropane triacrylate, 20% of BI-Std as biimidazole, 5% of 2-mercaptobenzthiazole and 5% of p-dimethylaminobenzaldehyde were added. The evaluation was performed under the same conditions except that the evaluation was performed. As a result, the initial sensitivity was 0.10 mj / cm ² and the rate of change in sensitivity was 0.58.

[0028]

Comparative Example 5 Evaluation was made under the same conditions as in Example 5 except that p-dimethylaminobenzaldehyde was omitted. As a result, the initial sensitivity was 0.12 mj / cm ² and the rate of change in sensitivity was 0.1%.
22.

[0029]

EXAMPLE 6 In Example 5, B was used as biimidazole.
The same evaluation was conducted except that 10% of I-1 was used, 2-mercaptobenzoxazole was used instead of 2-mercaptobenzothiazole, and the sensitizer was changed to NK. The initial sensitivity was 0.90 mj / cm ² , and the sensitivity was changed. The rate was 1.10.

[0030]

Comparative Example 6 Evaluation was made in the same manner as in Example 6 except that p-dimethylaminobenzaldehyde was omitted, and an initial sensitivity of 0.92 mj / cm ² and a sensitivity change rate of 0.75 were obtained.

────────────────────────────────────────────────── ⁶ Continuation of the front page (51) Int.Cl. ⁶ identification code FI G03F 7/027 502 G03F 7/027 502 (56) References JP-A-61-123602 (JP, A) JP-A-61-123603 JP-A-60-264279 (JP, A) JP-A-1-279903 (JP, A) JP-A-2-216154 (JP, A) JP-A-51-82102 (JP, A) JP-A-63-221109 (JP, A) JP-A-60-24542 (JP, A) JP-A-56-33640 (JP, A) JP-A-59-64840 (JP, A) (58) Int.Cl. ⁶ , DB name) G03F 7/028 C08F 2/50 G03F 7/004 G03F 7/027

Claims (3)

(57) [Claims] 1. A photopolymerizable composition comprising a polymerizable ethylenically unsaturated monomer, hexaarylbiimidazole, a sensitizer, and a dialkylaminoaryl aldehyde. 2. The composition according to claim 1, wherein said composition further contains a heterocyclic thiol. 3. The method according to claim 1, wherein the hexaarylbiimidazole is
The set according to claim 1, which is represented by the general formula [I].
Adult. Embedded image(Wherein, Ar₁Is an o-position substituted with a halogen atom.
Reel group, Ar _Two, Ar_ThreeAt least no
Is substituted with a carboalkoxy group or a halogen atom
Is an aryl group. )