JPH11271969A - Photopolymerizable composition and photosensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the photopolymerizable composition superior in sensitivity and stable in productivity and storage against time lapse and the photosensitive lithographic printing plate formed by using this composition. SOLUTION: The photosensitive composition comprises a monomer having an additionally polymerizable ethylenically unsaturated bond and a photopolymerization initiator and a polymer binder having a carboxylic groups in the molecule. This photosensitive photopolymerization initiator contains >=2 kinds of compounds represented by the formula. The photosensitive lithographic printing plate is formed by using this composition to form a photosensitive layer on a support. In the formula, each of R<1> -R<6> is an H atom or an alkyl, aralkyl, acyl, or alkoxycarbonyl group, or a hydrocarbon or heterocyclic ring or a -SO2 -R<8> group; R<8> is an H or alkali metal atom or a quaternary ammonium, alkyl, alkyl, or aralkyl group; and R<7> is an H atom or an alkyl or cyano or aryl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photopolymerizable composition and a photosensitive lithographic printing plate. In particular, the present invention exhibits extremely high sensitivity to light rays in the visible region, and furthermore, has high storage stability, production stability, and handleability. The present invention relates to an excellent photopolymerizable composition and a photosensitive lithographic printing plate manufactured using the photopolymerizable composition.

[0002]

2. Description of the Related Art Conventionally, many image forming methods using a photopolymerization system are known. For example, a photopolymerizable composition comprising a compound containing an addition-polymerizable ethylenic double bond, a photopolymerization initiator, and an organic polymer binder used as desired is prepared, and the photopolymerizable composition is supported. Prepare a light-sensitive material provided with a layer of a photopolymerizable composition by applying it on the body, exposing the desired image to polymerize and cure the exposed part, and dissolving and removing the unexposed part to form a cured relief image A method in which at least one is transparent in the same manner as above 2
A method in which a photosensitive material in which a photopolymerizable composition layer is provided between two sheets of a support is prepared, exposed from the transparent support side to cause a change in adhesive strength by light, and an image is formed by peeling the support. And an image forming method utilizing a change in toner adhesion due to light of the photopolymerizable composition layer.

In recent years, high-sensitivity photosensitive materials using a photopolymerizable photosensitive material have been studied in various application fields. Among these, there is a laser direct plate making system that is expected to be practically used, and a high-sensitivity photopolymer corresponding to exposure with a laser oscillation wavelength, for example, 488 nm light of an argon ion laser or 532 nm light of an FD-YAG laser. Development of a system is desired and various proposals have been made.

Several proposals have been made for a photopolymerization composition containing a photopolymerization initiation system which can respond to light in the visible light region. For example, a system of hexaarylbiimidazole and (p-dialkylaminobenzylidene) ketone (JP-A-47-2528, JP-A-54-1552)
No. 92, JP-A-56-166154), a system of ketocoumarin and an activator (JP-A-52-112681, JP-A-58-15503, JP-A-60-88005), substituted triazines And sensitizer system (JP-A-54-1)
No. 51024, JP-A-8-29803, JP-A-58-4
No. 0302), biidazole, styrene derivatives,
Thiol systems (JP-A-59-56403), organic peroxides and dye systems (JP-A-59-140203 and JP-A-59-189340), and other compounds such as titanocene compounds and sensitizers (JP-A-63-221110, JP-A-4-26154, JP-A-4-219756), and a system of a pyrromethene complex sensitizer and a radical generator (JP-A-4-241338, JP-A-7-5885). , JP-A-7
-225474).

Among these, a system of a pyrromethene complex sensitizer and a radical generator is particularly effective as a sensitizer for an FD-YAG laser with extremely high sensitivity to the wavelength around the FD-YAG laser described above (Japanese Patent Laid-Open No. (Pyrromethene complex sensitizers are disclosed in Japanese Patent Application No. Hei 8-5685).
It is also described in 196624. ).

[0006]

However, it has been clarified that this pyromethene complex sensitizer causes a defect which is considered to be crystallized upon some stimulation or storage over time.

That is, when a photopolymerizable composition containing one kind of a pyrromethene complex sensitizer is applied by an ordinary method on a usual laboratory scale, crystallization of the pyromethene complex sensitizer remarkably occurs. In many cases, the sensitizer is crystallized when subjected to stimuli (regardless of type) such as pressure, friction, or static electricity, or subjected to storage over time or accelerated deterioration test. I understood that. When a defect due to crystallization of the sensitizer occurs, not only does the color tone of that portion change, but also the sensitivity is greatly reduced locally.

[0008] Crystallization of the pyrromethene complex sensitizer due to the stimulus or the like becomes a serious problem when, for example, a photosensitive material is produced in a factory or the like. That is, when performing line production coating of the photopolymerizable composition in a factory or the like, hard chrome plating, Teflon,
Rollers made of various materials such as rubber are indispensable,
At this time, it is unavoidable that the photopolymerizable composition layer provided on the support comes into direct contact with the transport roller. In such cases, irritation such as pressure and friction (any kind)
Is directly provided to the photopolymerizable composition, and at this time, the crystallization of the pyromethene complex sensitizer is remarkably caused, and the possibility that the sensitivity is reduced by the crystallization is very high.

In addition, even if defects due to crystallization are not remarkable immediately after production, crystallization is often promoted with time, so that it is expected that a serious problem will occur in terms of storage stability.

[0010] For these reasons, the pyrromethene complex sensitizer is effective as a sensitizer for FD-YAG lasers, but has problems in terms of stable performance, stable productivity, and easy handling. it is conceivable that.

The present invention solves the above-mentioned conventional problems, and provides a photopolymerizable composition having excellent sensitivity, production stability, and storage stability over time, and a photosensitive composition using such a photopolymerizable composition. The purpose is to provide a lithographic printing plate.

[0012]

The photopolymerizable composition of the present invention comprises an ethylenically unsaturated double bond-containing monomer capable of addition polymerization, a photopolymerization initiator, and a polymer having a carboxyl group in the molecule. In a photopolymerizable composition containing a molecular binder, the photopolymerization initiator contains two or more compounds represented by the following general formula (I).

[0013]

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Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶
Are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, an aralkyl group, an acyl group, an alkoxycarbonyl group, a substituted or unsubstituted hydrocarbon ring group, a substituted or unsubstituted heterocyclic group, Alternatively, -SO ₃ -R ⁸ (R ⁸ is a hydrogen atom, a substituted or unsubstituted alkyl group, an aryl group, an aralkyl group, an alkali metal atom, or represents. a quaternary ammonium group) represents, R ⁷ is hydrogen Represents an atom, a substituted or unsubstituted alkyl group, a cyano group, or an aryl group. ) By using two or more pyromethene complex sensitizers represented by the above general formula (I) as a sensitizer, a photopolymerizable composition having excellent sensitivity, production stability, and storage stability over time can be obtained. Obtainable.

That is, the crystallization of a pyrromethene complex sensitizer can be greatly improved by using a mixture of two or more compounds having a specific skeleton and different in at least a part of the substituents as a sensitizer. And a photopolymerizable composition having high sensitivity, stable productivity, and excellent storage stability over time can be obtained.

The photosensitive lithographic printing plate of the present invention is obtained by forming a photosensitive layer on an aluminum support using such a photopolymerizable composition of the present invention.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the photopolymerizable composition of the present invention, an addition-polymerizable ethylenically unsaturated double bond-containing monomer (hereinafter abbreviated as "ethylenic monomer") contained as a first essential component. Is a monomer having an ethylenically unsaturated double bond such that when the photopolymerizable composition is irradiated with actinic rays, it undergoes addition polymerization by the action of the photopolymerization initiator, which is the second essential component, and cures. Body. In the present invention, the meaning of the monomer is a concept corresponding to a so-called polymer, and therefore includes not only a monomer in a narrow sense but also a dimer, a trimer, and an oligomer. It is.

The ethylenic monomer may be a compound having one ethylenically unsaturated double bond in one molecule. In this case, specifically, (meth) acrylic acid, (meth) Examples include alkyl esters of acrylic acid, acrylonitrile, styrene, monoesters of carboxylic acids having one ethylenically unsaturated double bond and poly (mono) hydric alcohols, and the like.

However, in the present invention, it is desirable to use a polyfunctional ethylenic compound having two or more ethylenically unsaturated double bonds in one molecule. Examples of such a polyfunctional ethylenic compound include, for example, Esters of aliphatic polyhydroxy compounds with unsaturated carboxylic acids; esters of aromatic polyhydroxy compounds with unsaturated carboxylic acids;
Esters obtained by an esterification reaction of a polyvalent hydroxy compound such as an aliphatic polyhydroxy compound and an aromatic polyhydroxy compound with an unsaturated carboxylic acid and a polyvalent carboxylic acid are exemplified.

The ester of the aliphatic polyhydroxy compound and the unsaturated carboxylic acid is not particularly limited,
For example, ethylene glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol Acrylic esters of aliphatic polyhydroxy compounds such as pentaacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexaacrylate, and glycerol acrylate; methacrylic esters in which the acrylate of these exemplified compounds is replaced with methacrylate; and itacone in which likewise itaconate is replaced Crotonic acid instead of acid ester and clonate Maleic acid esters in which instead of the ester or maleate and the like.

The ester of the aromatic polyhydroxy compound and the unsaturated carboxylic acid is not particularly limited, but examples thereof include aromatic polyhydroxy compounds such as hydroquinone diacrylate, hydroquinone dimethacrylate, resorcin diacrylate, resorcin dimethacrylate, and pyrogallol triacrylate. And methacrylic acid esters.

The ester obtained by the esterification reaction of the unsaturated carboxylic acid, polycarboxylic acid and polyhydroxy compound is not particularly limited, but typical examples include acrylic acid, phthalic acid and ethylene glycol. Condensate of acrylic acid, maleic acid, and condensate of diethylene glycol, methacrylic acid, condensate of terephthalic acid and pentaerythritol, acrylic acid,
And condensates of adipic acid, butanediol and glycerin.

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

As the photopolymerization initiator, which is the second essential component of the photopolymerizable composition of the present invention, any photopolymerization initiator that can initiate the polymerization of the ethylenic monomer can be used. In particular, those containing a sensitizer having photosensitivity to light in the visible region and an activator are preferably used.

Among them, examples of the activator which generates an active radical by exerting some action with a photo-excited sensitizer include titanocenes, hexaarylbiimidazoles, halogenated hydrocarbon derivatives, and diaryl iodides. And ammonium salts and organic peroxides. Among them, a composition using titanocenes or hexaarylbiimidazoles is particularly preferred because of good sensitivity, storage stability, adhesion of the formed coating film to the support, and the like.

Here, various titanocenes can be used.
396 and JP-A-61-151197 can be appropriately selected from various titanocenes. More specifically, di-cyclopentadienyl-
Ti-di-chloride, di-cyclopentadienyl-T
i-bis-phenyl, di-cyclopentadienyl-Ti
-Bis-2,3,4,5,6-pentafluorophenyl-
1-yl, di-cyclopentadienyl-Ti-bis-
2,3,5,6-tetrafluorophenyl-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophenyl-1-yl, dicyclopentadienyl-Ti-2 , 6-Di-fluorophenyl-1-yl, di-
Cyclopentadienyl-Ti-bis-2,4-di-fluorophenyl-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-tetrafluorophenyl-1- Yl, di-methylcyclopentadienyl-
Ti-bis-2,6-difluorophenyl-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluoro-3- (pyr-1-yl) -phenyl-1-yl and the like can be mentioned. be able to.

As the hexaarylbiimidazoles, various ones can be used.
2,2′-bis (o-chlorophenyl) -4,4 ′,
5,5′-tetra (p-fluorophenyl) biimidazole, 2,2′-bis (o-bromophenyl) -4,
4 ', 5,5'-tetra (p-iodophenyl) biimidazole, 2,2'-bis (o-chlorophenyl)-
4,4 ', 5,5'-tetra (p-chloronaphthyl) biimidazole, 2,2'-bis (o-chlorophenyl)
-4,4'5,5'-tetra (p-chlorophenyl) biimidazole, 2,2'-bis (o-bromophenyl)
-4,4 ', 5,5'-tetra (p-chloro-p-methoxyphenyl) biimidazole, 2,2'-bis (o-
Chlorophenyl) -4,4 ′, 5,5′-tetra (o,
p-dichlorophenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4′5,5′-tetra (o, p-dibromophenyl) biimidazole,
2'-bis (o-bromophenyl) -4,4'5,5 '
-Tetra (o, p-dichlorophenyl) biimidazole, 2,2'-bis (o, p-dichlorophenyl)-
Hexaarylbiimidazoles having a halogen substituent on the benzene ring such as 4,4'5,5'-tetra (o, p-dichlorophenyl) biimidazole are preferred.

These hexaarylbiimidazoles can be used in combination with various kinds of biimidazoles, if necessary. In this case, biimidazoles are described, for example, in Bull. Chem. Soc. Japan. 33,5
65 (1960) and J.A. Org. Chem. 36 [1
6] can be easily synthesized by the method disclosed in 2262 (1971).

Next, the sensitizer contained in the photopolymerization initiator will be described. The sensitizer in the present invention means a compound capable of effectively generating an active radical upon irradiation with visible light when coexisting with the above-mentioned activator.

In the present invention, as the sensitizer, a mixture of two or more compounds having the structure of the pyrromethene complex represented by the above general formula (I) and having at least a part of the substituents different from each other is used.

These sensitizers include, but are not limited to, for example, US Pat. H. Bog
er et al, Hetroatom Chemis
try, Vol. 1,5,389 (1990), U.S. Pat. Nos. 4,916,711 and 5,189,029.

[0033] In the present invention, at least one pyrromethene complex sensitizer represented by the general formula (I), R ¹
To at least one of R ⁷ has an alkyl group branched at the α-position or β-position, and particularly, R ² or R ⁵ has an α-position or β-position.
It preferably has an alkyl group branched at the position. This branched alkyl group is preferably represented by the following general formula (I).

[0034]

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(In the formula (II), R ⁹ and R ¹⁰ have 1 to 1 carbon atoms.
0 preferably represents an alkyl group of 1 to 7, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and q represents 0 or 1. This branched alkyl group is more preferably in the α-position or in the β-position.
3-20 carbon atoms having a secondary or tertiary carbon atom at the -position
And more preferably an alkyl group having 4 to 7 carbon atoms having a tertiary carbon atom at the α-position or β-position.

The pyrromethene complex sensitizer in which an alkyl group having a secondary or tertiary carbon atom at the α-position or the β-position is introduced, compared to a pyromethene complex sensitizer in which the corresponding alkyl group is linear. The absorption wavelength peak is shifted to the longer wavelength side and the 488 nm argon ion laser or 532 nm
Sensitivity to the oscillation wavelength of the YAG laser is increased. Further, this pyromethene complex sensitizer has good solubility in various coating solvents.

Specific examples of the alkyl group having a branched α-position include the following (in the following formula, q is the same as defined above).

[0038]

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Of the substituents R ^{1 to} R ^{7 in} the general formula (I), the substituents R ^{1 to} R ⁶ other than the above-mentioned alkyl group branched at the α-position or β-position are preferably , A hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, and an alkoxycarbonyl group having 2 to 10 carbon atoms.
R ⁷ is preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a cyano group.

More specifically, examples of the substituted or unsubstituted alkyl group used for R ^{1 to} R ⁸ include the following.

[0041]

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Examples of the acyl group used for R ^{1 to} R ⁶ include the following.

[0043]

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Examples of the alkoxycarbonyl group used for R ^{1 to} R ⁶ include the following.

[0045]

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As the substituted or unsubstituted hydrocarbon ring group used for R ^{1 to} R ⁶ , preferred are an aryl group having 1 to 3 rings and an aliphatic hydrocarbon ring group having 6 to 10 carbon atoms. The following can be specifically mentioned.

[0047]

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Representative examples of the pyrromethene complex sensitizer represented by the general formula (I) suitable for the present invention are shown in Tables 1 to 9 showing the substituents R ^{1 to} R ⁷ of the general formula (I). The pyromethene complex sensitizer according to the present invention is not limited to these exemplified compounds.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

[0052]

[Table 4]

[0053]

[Table 5]

[0054]

[Table 6]

[0055]

[Table 7]

[0056]

[Table 8]

[0057]

[Table 9]

In the present invention, two or more of the above pyromethene complex sensitizers are used in combination, and the proportion of the use of one type of the pyrromethene complex sensitizer is determined based on the total amount of the pyrromethene complex sensitizer. 3 to 97%, especially 5 to 95
%, Especially 10 to 90%.

Next, a polymer binder having a carboxyl group in the molecule, which is the third essential component of the present invention, will be described. Specific examples of the polymer binder include, for example,
(Meth) acrylic acid, (meth) acrylic acid ester,
(Meth) acrylamide, maleic acid, (meth) acrylonitrile, styrene, vinyl acetate, vinylidene chloride,
Examples thereof include homo- or copolymers of maleimide and the like, polyethylene oxide, polyvinyl pyrrolidone, polyamide, polyurethane, polyester, polyether, polyethylene terephthalate, acetyl cellulose, and polyvinyl butyral. Among them, a copolymer containing at least one (meth) acrylic acid ester and (meth) acrylic acid as a copolymer component is preferable. The preferred acid value of the polymer binder having a carboxyl group in the molecule is 10 to 250, and the preferred weight average molecular weight (hereinafter abbreviated as Mw) is 5,000 to 1,000,000.

It is desirable that these polymer binders have an unsaturated bond in a side chain, and in particular, the following general formulas (1) to (1).
It preferably has at least one type of unsaturated bond represented by (3).

[0061]

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(Wherein R ¹¹ represents a hydrogen atom or a methyl group. R ^{12 to} R ¹⁶ each independently represent a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, Having a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent An optionally substituted aryloxy group, an optionally substituted alkylamino group, an optionally substituted arylamino group, an optionally substituted alkylsulfonyl group, or a substituent Having an arylsulfonyl group optionally having
Represents an oxygen atom, a sulfur atom, an imino group, or an alkylimino group. The methods for synthesizing such a polymer binder are roughly classified into the following two methods.

(Synthesis Method 1) An inert organic solvent solution of a polymer binder having a carboxyl group in the molecule (for example, alcohol-based, ester-based, aromatic hydrocarbon-based, aliphatic hydrocarbon-based, etc.) A method of reacting an unsaturated compound having an epoxy group with an epoxy group under a reaction condition of about 80 to 120 ° C. for about 1 to 50 hours. The ratio of the carboxyl group to be reacted with the epoxy group-containing unsaturated compound is not particularly limited as long as the effect of the present invention can be achieved, but it is preferable to react 5 to 90 mol% with respect to all the carboxyl groups. Preferably it is 20 to 80 mol%, more preferably 30 to 70 mol%. Within the above range, the developing property is good and the adhesive property is good.

The epoxy group-containing unsaturated compound used herein is a compound having at least one addition-polymerizable unsaturated bond and an epoxy group in one molecule.

Examples of the epoxy group-containing unsaturated compound include glycidyl (meth) acrylate, allyl glycidyl ether, α-ethyl glycidyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, glycidyl isocrotonate, monoalkyl itaconate monoglycidyl ester And aliphatic epoxy group-containing unsaturated compounds such as fumaric acid monoalkyl ester monoglycidyl ester and maleic acid monoalkyl ester monoglycidyl ester, and alicyclic epoxy group-containing unsaturated compound represented by the following structure.

[0066]

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[0067]

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(In each formula, R ²¹ represents a hydrogen atom or a methyl group. R ²² represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms. R ²³ represents a C 1-10 carbon atom.) It represents a divalent hydrocarbon group, and k represents an integer of 0 to 10.) Specific examples of preferred compounds of the epoxy group-containing unsaturated compound include glycidyl methacrylate, allyl glycidyl ether, and 3,4-epoxycyclohexyl. Methyl acrylate and the like can be mentioned. Particularly preferred compounds among these are allyl glycidyl ether, 3,4-
Epoxycyclohexylmethyl acrylate is mentioned.

(Synthesis Method 2) The above general formulas (2) and (3)
And at least one kind of unsaturated bond having low reactivity and one kind of unsaturated bond having higher reactivity than these.
A method of synthesizing a compound having at least one kind of unsaturated bond and an unsaturated carboxylic acid by copolymerization.

Specific examples of the compound having an unsaturated group represented by the general formula (2) include allyl (meth) acrylate, 3-allyloxy-2-hydroxypropyl (meth) acrylate, and N, N-diallyl (meth) acrylate. Acrylamide, cinnamyl (meth) acrylate, crotonyl (meth) acrylate, methallyl (meth) acrylate and the like can be mentioned.

Specific examples of the compound having an unsaturated group represented by the general formula (3) include vinyl (meth) acrylate, vinyl crotonate, 1-propenyl (meth) acrylate, 1-chlorovinyl (meth) acrylate, 2
-Phenyl vinyl (meth) acrylate, vinyl (meth) acrylamide and the like.

Among the compounds having the structures (2) and (3), preferred compounds include allyl methacrylate and vinyl methacrylate.

These monomers are copolymerized with an unsaturated carboxylic acid, preferably acrylic acid or methacrylic acid, to obtain a copolymer having the unsaturated group. As the monomer to be copolymerized, another monomer may be copolymerized in addition to the unsaturated carboxylic acid, and examples thereof include alkyl acrylate, alkyl methacrylate, acrylonitrile, and styrene. The ratio of the compound having the structure of (2) or (3) to the total components of the polymer to be copolymerized is preferably 10 to 90 mol%, more preferably 30 to 80 mol%. If the ratio is less than the above range, the image reproducibility is poor, and if the ratio is large, the developability deteriorates.

The main constituents of the photopolymerizable composition of the present invention have been described in detail above. The preferred ratio of use is that the photopolymerization initiator is added to 100 parts by weight of the polymerizable ethylenic compound. The sensitizer is preferably 0.01 to 20 parts by weight, particularly preferably 0.05 to 10 parts by weight, and the activator is preferably 0.1 to 80 parts by weight, particularly preferably 0.5 to 10 parts by weight.
60 parts by weight, and preferably a polymer binder is 10 to 4 parts by weight.
00 parts by weight, particularly preferably 20 to 200 parts by weight.

The photopolymerizable composition of the present invention may further contain other substances depending on the purpose in addition to the above essential components. For example, thermal polymerization inhibitors such as hydroquinone, p-methoxyphenol, 2,6-di-t-butyl-p-cresol; coloring agents composed of organic or inorganic dyes and pigments; dioctyl phthalate, didodecyl phthalate, tricresyl Plasticizers such as phosphates; sensitivity property improvers such as tertiary amines and thiols; and other additives such as dye precursors can also be added. The preferred amount of these additives is 100 parts by weight of the ethylenic compound. 2 parts by weight or less of thermal polymerization inhibitor, 20 parts by weight or less of colorant, plasticizer 4
The range is 0 part by weight or less, the sensitivity characteristic improving agent is 40 parts by weight or less, and the dye precursor is 30 parts by weight or less.

Further, the photopolymerizable composition of the present invention may contain a surfactant as a coatability improving agent. In this case, the surfactant is not particularly limited, but is an alkyl group having 6 to 10 carbon atoms as shown below, and 12 to 20 hydrogen atoms among the hydrogen atoms of the alkyl group are substituted with fluorine atoms. Fluorinated surfactants having a modified fluoroalkyl group can be used.

[0077]

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Examples of these fluorine-based surfactants include, for example, Surflon “S-381” and “S-38”
2 "," SC-101 "," SC-102 "," SC-102 "
103 ”and“ SC-104 ”(both by Asahi Glass Co., Ltd.)
Co., Ltd.), Florard “FC-430”, “FC-43”
1 "," FC-173 "(all from Fluorochemicals-manufactured by Sumitomo 3M), F-top" EF352 "," EF
301 ”and“ EF303 ”(both from Shin-Akita Chemical Co., Ltd.)
Manufactured), Shubego Fuller “8035”, “8036”
(All manufactured by Schwegman), "BM1000",
Commercially available products such as "BM1100" (all manufactured by BM Himmy) can be used.

The preferred addition amount of these surfactants is
Within a range of 10 parts by weight or less, more preferably 0.01 part by weight, based on 100 parts by weight of the ethylenic compound in the photopolymerizable composition
-5 parts by weight.

The photopolymerizable composition of the present invention is diluted with an appropriate solvent, coated on a support and dried to form a photosensitive layer.

Hereinafter, a method for producing a photosensitive lithographic printing plate using the photopolymerizable composition of the present invention will be described.

As the support for the photosensitive lithographic printing plate, an aluminum support whose surface has been roughened and then anodized is preferably used. As a method of this surface roughening, generally known brush polishing method, ball polishing method, electrolytic etching,
Examples include methods such as chemical etching, liquid honing, and sand blasting, and combinations thereof, and preferably include brush polishing, ball polishing, electrolytic etching, chemical etching, and liquid honing. Further, the roughened aluminum plate is desmutted with an acid or alkali aqueous solution as needed. The aluminum plate thus obtained is usually anodized,
Particularly preferred is a method of treating with an electrolytic solution containing sulfuric acid. The method of anodizing with an electrolytic solution containing sulfuric acid is performed according to a conventionally known method, for example, a method described in JP-A-58-21894. Specific processing conditions are 5 to 50% by weight of sulfuric acid, preferably 15 to 30% by weight.
Temperature is about 5 to 50 ° C., preferably 15 to
~ 35 ° C, current density 1 ~ 60A / dm ² for 5 seconds ~
This is performed for about 60 seconds. Further, if necessary, the surface is treated with an alkali silicate such as sodium silicate treatment or hot water, or immersed in an aqueous solution containing an aqueous polymer compound such as a resin having a cationic quaternary ammonium group or polyvinylphosphonic acid. Processing can be performed.

As a method for applying the photopolymerizable composition to such a support, well-known methods such as dip coating, coating rod, spinner coating, spray coating and roll coating are employed.

Further, on the photosensitive layer formed by applying the photopolymerizable composition, an oxygen blocking layer can be provided in order to prevent a polymerization inhibiting action by oxygen. Specific examples thereof include water-soluble polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, and cellulose. Among them, those containing polyvinyl alcohol having particularly high oxygen gas barrier properties are preferable.

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. Laser, Y
An AG laser, a helium neon laser or the like is particularly suitable.

The photopolymerizable composition of the present invention can form an image on a support by performing image exposure with such a light source and developing with an aqueous solution containing a surfactant and an alkali. . The aqueous solution may further contain an organic solvent, a buffer, a dye or a pigment.

Suitable alkali agents for development include sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium tertiary phosphate, dibasic sodium phosphate, sodium carbonate, potassium carbonate, bicarbonate. Inorganic alkali agents such as sodium, trimethylamine, diethylamine, monoisopropylamine, n-
Organic amine compounds such as butylamine, monoethanolamine, diethanolamine, and triethanolamine are exemplified, and these can be used alone or in combination of two or more. Examples of the surfactant include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, and monoglyceride alkyl esters; alkylbenzene sulfonic acid Anionic surfactants such as salts, alkyl naphthalene sulfonates, alkyl sulfates, alkyl sulfonates, sulfosuccinate salts; and amphoteric surfactants such as alkyl betaines and amino acids can be used. Further, as the organic solvent, for example, isopropyl alcohol, benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol, diacetone alcohol, and the like can be contained as necessary.

[0088]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples unless it exceeds the gist thereof.

Production Example 1: Synthesis of polymer binder (1) Methyl methacrylate / isobutyl methacrylate / isobutyl acrylate / methacrylic acid = 35/20 /
10/35 mol% (charge ratio) of copolymer (Mw = 7)
Ten thousand. Hereinafter, it is abbreviated as “binding material-1”. ) 200 parts by weight, 75 parts by weight of the following alicyclic epoxy-containing unsaturated compound, 2.5 parts by weight of p-methoxyphenol, 8 parts by weight of tetrabutylammonium chloride, and 800 parts by weight of propylene glycol monomethyl ether acetate in a reaction vessel. In addition, an ethylenic polymer binder (acid value 60, 60% of the entire methacrylic acid component of the binder-1 was reacted with unsaturated groups by stirring reaction at 110 ° C. for 24 hours in air.
Hereinafter, it is abbreviated as “binding material-2”. ) A solution was obtained.

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Production Example 2: Synthesis of Polymer Binder (2) Copolymer of (α-methyl) styrene / acrylic acid (trade name “SCX-690” manufactured by Johnson, acid value 24)
(0, Mw = 15,000) 855 parts by weight, 490 parts by weight of the same alicyclic epoxy-containing unsaturated compound as used in Production Example 1, 1.3 parts by weight of p-methoxyphenol, 4.3 parts by weight of tetraethylammonium chloride Parts by weight and 1,800 parts by weight of propylene glycol monomethyl ether acetate are added to a reaction vessel, and the mixture is stirred and reacted at 120 ° C. for 15 hours in air to obtain an ethylenic polymer binder (acid value of about 17).
0, (α-methyl) styrene / acrylic acid copolymer in which unsaturated groups have reacted with 50% of the entire acrylic acid component.
Hereinafter, it is abbreviated as “binding material-3”. ) A solution was obtained.

Production Example 3 Synthesis of Polymer Binder (3) 67 g of vinyl methacrylate, 20 g of methyl methacrylate, 17 g of methacrylic acid were placed in a 3 L four-necked flask equipped with a stir bar with wings, reflux cooling, and a nitrogen tube. 1.6 L of ethanol was added as a reaction solvent, and the mixture was heated and stirred in a 90 ° C. oil bath. 1.6 g of azobisisobutyronitrile dissolved in 400 mL of ethanol was added to this solution.

After heating and stirring for 3 hours, the nitrogen tube was removed and p
0.04 g of -methoxyphenol and 400 mL of propylene glycol monomethyl ether acetate were added, the bath temperature was raised to 100 ° C, and heating and stirring were continued for 1 hour.
Finally, ethanol was distilled off to obtain an 18% by weight solution of an ethylenic polymer binder (Mw: 140,000; hereinafter abbreviated as “binder-4”).

[0094] Production Example 4: Preparation (1) Na ₂ CO ₃ 0.03 mol of the developer, NaHCO ₃ 0.10 moles respectively dissolved in water of 1L, was added 80mL of Kao Corporation surfactant Pelex NBL liquid Was used as a developer (pH =
9.3, conductivity 12 mS / cm).

Production Example 5: Production of aluminum support (1) An aluminum plate was degreased with 3% sodium hydroxide, and this was immersed in a 11.5 g / L hydrochloric acid bath at 25 ° C. and 80 A / dm ^2.
Was electrolytically etched at a current density of 11 seconds, washed with water, and then anodized in a 30% sulfuric acid bath at 30 ° C. and 11.5 A / dm ² for 15 seconds. Thereafter, the plate was washed with water and dried to obtain an aluminum plate for a lithographic printing plate (hereinafter abbreviated as "support-1").

Production Example 6: Production of aluminum support (2) Support-1 was further hydrophilized at 85 ° C. for 30 seconds using a 1% by weight aqueous sodium orthosilicate solution, washed with water and dried to obtain aluminum for a lithographic printing plate. A plate (hereinafter, abbreviated as “support-2”) was obtained.

Examples 1 to 7 and Comparative Examples 1 to 5 On a support shown in Tables 10 and 11, a photopolymerizable composition coating solution-1 having the following composition was dried with a bar coater at a dry film thickness of 2 g /.
It was applied and dried such that m ^2.

Thereafter, a 10 cm × 10 cm plate subjected to hard chromium plating was placed on the photopolymerizable composition, and
A kg weight was placed and left overnight. This was performed 10 times for each photopolymerizable composition.

After standing overnight, an aqueous solution of polyvinyl alcohol was further applied onto the photopolymerizable composition using a bar coater to a dry film thickness of 3 g / m ² and dried. The following items were evaluated in the obtained photopolymerizable composition on the support, and the results are shown in Tables 10 and 11.

[Composition of Photopolymerizable Composition Coating Solution-1] Ethylene monomer shown in Tables 10 and 11 in total of 55 parts by weight among compounds 1 to 4 having the following structures Polymer binder shown in Tables 10 and 11 45 Parts by weight Among the sensitizers having the following structures, the sensitizers shown in Tables 10 and 11 total 2.0 parts by weight Titanocene compounds having the following structure 10 parts by weight 2-mercaptobenzothiazole 5.0 parts by weight N, N-dimethylbenzoic acid Ethyl ester 10 parts by weight Copper phthalocyanine pigment 3.0 parts by weight Cyclohexanone 1090 parts by weight

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[0102]

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[0103]

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[Evaluation Items] <Sensitizer Crystallization Generation Level> In the photopolymerizable composition on the support, the defect generation level due to crystallization of the sensitizer was evaluated. That is, as described above, put a 10 cm × 10 cm plate hard-chromium plated on the photopolymerizable composition,
A 2 kg weight was placed on it and left overnight. This was performed 10 times for each photopolymerizable composition. The level at which crystallization did not occur at all 10 times was represented by ○, the level at which crystallization was observed 1 to 3 times out of 10 times, and the level at which crystallization occurred 4 to 10 times.

<Sensitivity> The photopolymerizable composition coated and dried on the support was exposed and developed using a diffraction spectral irradiation apparatus (“RM-23” manufactured by Narumi), and the cured image obtained was obtained. The amount of light energy required for photo-curing with a light beam of 532 nm was determined from the height. Further, with respect to the plate in which crystallization of the sensitizer occurred, the amount of light energy required for photocuring was determined in the same procedure for the sensitivity of the portion where crystallization occurred.

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[Table 10]

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[Table 11]

Tables 10 and 11 show that the photopolymerizable composition of the present invention has excellent sensitivity and stability.

The photopolymerizable compositions of Examples 1 and 2 were further added with a fluorinated surfactant "S-3" manufactured by Asahi Glass Co., Ltd.
81 "(trade name) was added in the same manner except that 0.3 parts by weight was added. As a result, the coatability was greatly improved while maintaining the defect generation level and sensitivity, and a clean coated surface was obtained.

[0110]

As described in detail above, according to the present invention, a photopolymerizable composition having both excellent sensitivity, production stability, and storage stability over time, and a photosensitive composition using such a photopolymerizable composition. A lithographic printing plate is provided.

Claims (8)

[Claims] 1. A photopolymerizable composition comprising an addition-polymerizable ethylenically unsaturated double bond-containing monomer, a photopolymerization initiator, and a polymer binder having a carboxyl group in the molecule. , Wherein the photopolymerization initiator contains two or more compounds represented by the following general formula (I). Embedded image (In the formula (I), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, an aralkyl group, an acyl group , an alkoxycarbonyl group, a substituted or unsubstituted hydrocarbon ring group, a substituted or unsubstituted heterocyclic group, or, -SO ₃ -R ⁸ (R ⁸ is a hydrogen atom, a substituted or unsubstituted alkyl group, an aryl group, Represents an aralkyl group, an alkali metal atom, or a quaternary ammonium group), and R ⁷ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a cyano group, or an aryl group. 2. The method according to claim 1, wherein at least one of the compounds represented by formula (I) has an α-position or a β-position at least one of R ^{1 to} R ^7.
The photopolymerizable composition according to claim 1, having an alkyl group branched at the -position. 3. The compound according to claim 1, wherein at least one of the compounds represented by the general formula (I) has an alkyl group branched at the α-position or the β-position at R ² or R ^5. 3. The photopolymerizable composition according to item 1. 4. The compound according to claim 1, wherein at least one of the compounds represented by the general formula (I) has a branched alkyl group represented by the following general formula (II) in at least one of R ^{1 to} R ^7. Item 4. The photopolymerizable composition according to item 2 or 3. Embedded image (In the formula (II), R ⁹ and R ¹⁰ represent an alkyl group having 1 to 10 carbon atoms, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and q represents 0 or 1.) 5. A group other than the branched alkyl group represented by the general formula (II) among R ^{1 to} R ⁷ in the general formula (I) is each independently a hydrogen atom or an alkyl group having 1 to 9 carbon atoms. The photopolymerizable composition according to claim 4, wherein: 6. The photopolymerizable composition according to claim 4, wherein R ^{9 to} R ¹¹ in formula (II) are each independently a hydrogen atom or an alkyl group having 1 to 7 carbon atoms. Composition. 7. The photopolymerization initiator according to claim 1, wherein the photopolymerization initiator contains a titanocene compound.
The photopolymerizable composition according to item. 8. A photosensitive lithographic printing plate having a photosensitive layer containing the photopolymerizable composition according to claim 1 on an aluminum support.