JPH1087733A - Photosensitive composition, photosensitive lithographic printing plate material and formation of image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve printing resistance of a prepared lithographic printing plate without deteriorating developing rate of a photosensitive lithographic printing plate material of a system used by combining an agent for generating an acid by irradiation of light with an acid-decomposing compound. SOLUTION: This photosensitive composition comprises a vinyl polymer having a graft group formed from at least one kind of compound selected from an orthocarboxylic ester, an acetal and an ketal on the side chain. This photosensitive lithographic printing plate material is formed by applying the photosensitive composition onto the surface having hydrophilic property of a hydrophilic support. The method for forming image comprises exposing a photosensitive lithographic printing plate material to infrared rays and removing the exposed part with an alkaline developer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel photosensitive composition, a photosensitive lithographic printing plate material using the same, and an image forming method.

[0002]

2. Description of the Related Art Conventionally, an acid generator which generates an acid upon irradiation with light (hereinafter also referred to as a photoacid generator) and a compound which can be decomposed by the acid (hereinafter also referred to as an acid-decomposable compound). An image forming material having a photosensitive layer is known. US Pat. No. 3,779,778 discloses a photosensitive composition containing a compound having an orthocarboxylic acid ester group or a carboxylic acid amide acetal group. 53-1 Kaisho
No. 33429 discloses a photosensitive composition containing a compound having an acetal group or a ketal group in the main chain.
No. 0-37549 discloses a photosensitive composition containing a compound having a silyl ether group. All of them have sensitivity to ultraviolet light, and are alkali-solubilized by exposure to ultraviolet light to become non-image areas.However, when a lithographic printing plate is prepared using these compositions, quinonediazide is used as a photosensitive material. The printing durability is inferior to that formed using the composition.

As a technique for improving printing durability, Japanese Patent Publication No.
No. 43940 describes that two or more kinds of alkali-soluble resins having different solubilities are used. However, according to this, the printing durability is improved but the developing speed is deteriorated.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a photosensitive lithographic printing plate material of a system using a combination of a photoacid generator and an acid-decomposable compound. Another object of the present invention is to improve the printing durability of the prepared lithographic printing plate without deteriorating the developing speed.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide a photosensitive composition containing a vinyl polymer having on its side chain a graft group formed from at least one selected from orthocarboxylic esters, acetals and ketals. Product, further comprising a photoacid generator, the photoacid generator having a methyl trihalide group, containing a dye having absorption in the infrared region, the hydrophilic surface of the hydrophilic support A photosensitive lithographic printing plate material formed by applying the above photosensitive composition thereon, and an image forming method for exposing the photosensitive lithographic printing plate material using infrared rays and removing exposed portions with an alkaline developer Is achieved by

[0006] In the photosensitive lithographic printing plate material of the present invention, the photosensitive composition to be coated preferably further contains a phenol resin.

Hereinafter, the present invention will be described in detail for each item.

<< Photosensitive Composition >> The photosensitive composition of the present invention is a graft formed from at least one selected from orthocarboxylic acid esters, acetals and ketals (hereinafter also referred to as the acid-decomposable compound of the present invention). It is characterized by containing a vinyl polymer having a group in a side chain.

The orthocarboxylic acid ester used in the present invention includes orthoformate, orthoacetate, orthopropionate, orthobenzoate, orthocyclohexanecarboxylate, preferably trinonyl orthoformate, triformate orthoformate. Decyl ester, triundecyl orthoformate,
Tridodecyl orthoformate, tritetradecyl orthoformate, trihexadecyl orthoformate, tristearyl orthoformate, trioleanyl orthoformate, tris-3-oxa-decyl orthoformate, tris-orthoformate , 6-dioxa-dodecyl ester, orthoformic acid-tris-3,
6,9, -trioxa-tridecyl ester, orthoformic acid-tris-3,6,9,12-tetraoxa-hexadecyl ester, orthoformic acid-tris-3,6,9,1
2,15-pentaoxa-heptadecyl ester, orthoformic acid-tris-3,6,9,12,15,18,2
1,24-octaoxa-pentacosyl ester, tris-3,6,9-trioxa-tridecyl orthoacetate, tris-3,5,5-trimethylhexyl orthoformate, tris-4,9 orthoformate 12
-Trimethyl-pentadecyl ester and orthoformate of tripropylene glycol monomethyl ether.

The acetal is advantageously obtained by reacting an appropriate aldehyde or a derivative thereof with an alcohol, and the ketal is obtained by reacting an appropriate ketone or a synthetic equivalent thereof with an alcohol.

Examples of the above aldehyde include acetaldehyde, chloral, ethoxyacetaldehyde, benzyloxyacetaldehyde, phenylacetaldehyde, diphenylacetaldehyde, phenoxyacetaldehyde, propionaldehyde, 2-phenyl-propionaldehyde, 3-phenyl-propionaldehyde, isobutoxypivalin Aldehyde, benzyloxypivalinaldehyde, 3-ethoxypropanal, 3-
Cyano-propanal, n-butanal, iso-butanal, 3-chloro-butanal, 3-methoxy-butanal, 2,2-dimethyl-4-cyano-butanal, n
-Pentanal, 2-methyl-pentanal, 3-methyl-pentanal, 2-bromo-3-methyl-butanal, n-hexanal, 2-ethyl-butanal, 3-
Ethyl-butanal, 4-methyl-pentanal, cyclopentanecarbaldehyde, n-heptanal, cyclohexanecarbaldehyde, 1,2,3,6-tetrahydro-benzaldehyde, 3-ethyl-pentanal, 3-methyl-hexanal, 4-methyl -Hexanal, n-octanal, 2-ethyl-hexanal,
4-ethyl-hexanal, 3,5,5-trimethyl-
Hexanal, 4-methyl-heptanal, 3-ethyl-n-heptanal, decanal, monooxo synthesis product of dicyclopentadiene, dodecanal, crotonaldehyde, benzaldehyde, 2-, 3- and 4-bromo-benzaldehyde, 2-, 3 -And 4-chloro-benzaldehyde, 2,4-dichloro- and 3,4-dichloro-benzaldehyde, 4-methoxy-benzaldehyde, 2,3-dimethoxy- and 2,4-dimethoxy-
Benzaldehyde, 2-, 3- and 4-fluoro-benzaldehyde, 2-, 3- and 4-methyl-benzaldehyde, 4-isopropyl-benzaldehyde, 3- and 4-tetrafluoroethoxy-benzaldehyde, 1
-And 2-naphthaldehyde, furfural and thiophene-2-aldehyde.

As ketones for deriving the ketal, phenylacetone, 1,3-diphenylacetone, 2,2-
Diphenylacetone, chloro or bromoacetone, benzylacetone, butan-2-one, benzyl-propylketone, ethylbenzylketone, benzylmethylketone, 5-methyl-hexane-2-one, 2-methyl-pentan-2-one, 2-methyl-pentan-3-one,
Hexane-2-one, hexane-3-one, pentane-
3-one, 2-methyl-butan-3-one, 2,2-dimethyl-butan-3-one, 5-methyl-heptane-3
-One, octane-3-one, octane-4-one, octane-2-one, nonan-2-one, nonan-3-one, nonan-5-one, heptane-2-one, heptane-3-one , Heptane-4-one, undecane-5-one, undecane-6-one, dodecane-2-one, dodecane-3-one, dinonylketone, undecane-4-one, undecane-2-one, tridecane-2-one , Tridecane-3-one, dodecane-5-one, dioctylketone, 2-methyl-octane-3-one, cyclopropylmethylketone, decane-2-one, decane-3-one, decane-4-one, methyl -Α-naphthyl-ketone, didecyl ketone, diheptyl ketone, dihexyl ketone, 3-fluoro-4-methoxy-acetophenone,
Acetophenone, 4-chloro-acetophenone, 2,5
-Dichloro-acetophenone, 4-bromo-acetophenone, 2,4-dimethyl-acetophenone, 2-, 3-
And 4-fluoroacetophenone, desoxybenzoin, 2-, 3- and 4-methoxy-acetophenone,
-, 3- and 4-methyl-acetophenone, propiophenone, 2-bromo-propiophenone, 4-fluoro-propiophenone, 4-methoxy-propiophenone, butyrophenone, 4-chloro-butyrophenone, valerophenone, benzophenone , 4-chloro-benzophenone, 4,4'-dichloro-benzophenone, 2,5
-Dimethyl-benzophenone, 3,4-dimethyl-benzophenone, 2- and 4-fluoro-benzophenone,
4-methoxy-benzophenone, cyclohexanone, 2
-Phenyl-cyclohexanone, 2-, 3- and 4-methyl-cyclohexanone.

As the alcohol, a monohydric or dihydric alcohol is preferably used, and as the monohydric alcohol, methanol, ethanol, iso-propanol,
Aliphatic alcohols such as benzyl alcohol; cellosolves such as methyl cellosolve, ethyl cellosolve and phenyl cellosolve; propylene glycols such as propylene glycol monomethyl ether, propylene glycol monoethyl ether and propylene glycol monophenyl ether; diethylene glycol monomethyl ether and diethylene glycol mono Ethyl ethers, diethylene glycols such as diethylene glycol monophenyl ether; triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycols such as triethylene glycol monophenyl ether, and the like are preferably used. As a dihydric alcohol, Triethylene glycol, tetraethylene glycol, hex Ethylene glycol, aliphatic diols such as propylene glycol or diethylene glycol, dipropylene glycol, tetraethylene glycol or the like is used.

The graft group to be formed is preferably represented by the general formula (1) or (2). More preferably, the graft group represented by the general formula (1)

[0015]

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Wherein ₁ represents 5 to 12 and R ₁ ′
Is a hydrogen atom, a methyl group or an ethyl group, and R ₅ is a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms,
6 represents an alkyl group, a sulfonylamido group or a carboxy group, and R ₃ , R ₄ and X are as defined above.

Further, in the general formula (1), preferably, R ₃
Is an alkylene group having 2 to 4 carbon atoms, R ₄ is a phenyl group or a naphthyl group, and X is —O—.

In the graft group represented by the general formula (2), preferred R _{1 to} R ₃ are the same as those of the preferred compound of the general formula (1), and m is preferably 2 to 4.

The vinyl polymer may be a copolymer with a known monomer, and has a weight average molecular weight of 2,000 to 2,000.
It is about 00, preferably 5,000 to 100,000.
Preferably, the graft group of the present invention is introduced into the structural units shown below.

[0020]

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[0021] In the formula, the R ₆ is a hydrogen atom or a methyl group, R ₇
Represents an alkylene group having 1 to 6 carbon atoms, and X and l have the same meanings as those in formula (1).

Most preferably, the vinyl polymer has a derivative of 2-hydroxyethyl methacrylate or 2-allyl alcohol as a structural unit. The vinyl polymers may be bonded to each other by a graft group to form a three-dimensional structure.

The vinyl polymer of the present invention will be described in more detail later in the section of photosensitive lithographic printing plate material.

The following are some examples of the synthesis of vinyl polymers having a graft group formed from the acid-decomposable compound of the present invention in the side chain (referred to as acid-decomposable compound graft polymers).

<Synthesis of Acid Decomposable Compound Graft Polymer A> 200 ml of ethanol was placed in a 500 ml four-necked flask equipped with a thermometer, a reflux condenser, a stirrer, and a nitrogen inlet tube.
1 and a polymer compound (hereinafter referred to as a trunk polymer)
26.03 g (0.20 mol) of 2-hydroxyethyl methacrylamide, 35.44 g (0.20 mol) of 4-hydroxyphenyl methacrylamide, 13.27 g (0.25 mol) of acrylonitrile, methacrylic acid 4.30 g (0.05 mol) and 30.3 g (0.30 mol) of methyl methacrylate were dissolved. Further, as a polymerization initiator, hydroquinone 0.05
0 g was added to terminate the reaction.

Next, 28.84 g (0.20 mol) of 1,1-dimethoxycyclohexane, phenyl cellosolve 2
After charging 7.63 g (0.20 mol), ethanol as a reaction solvent used for radical polymerization is distilled off under reduced pressure. Then, 60 mg of p-toluenesulfonic acid was added,
React for 1 hour at 100 ° C. in an oil bath. Then, the reaction temperature was raised to 150 ° C., and the reaction was carried out for 5 hours while distilling off methanol as a reaction by-product, to obtain an acid-decomposable compound graft polymer A. The obtained polymer was subjected to gel permeation chromatography (GPC) to obtain a pullulan standard,
When measured with N, N-dimethylformamide solvent,
The weight average molecular weight was 12,000.

<Synthesis of Acid Decomposable Compound Graft Polymer B> A trunk polymer was synthesized in the same manner as for Polymer A. Next, 28.84 g of 1,1-dimethoxycyclohexane
(0.20 mol), triethylene glycol 30.03
g (0.20 mol), ethanol as a reaction solvent used for radical polymerization is distilled off under reduced pressure. Then, 60 mg of p-toluenesulfonic acid is added, and the mixture is reacted at 100 ° C. for 1 hour in an oil bath. Then the reaction temperature was increased to 150
C., and the reaction was carried out for 5 hours while distilling off methanol as a reaction by-product, to obtain an acid-decomposable compound graft polymer B. The obtained polymer was subjected to GPC by pullulan standard,
When measured with N, N-dimethylformamide solvent,
The weight average molecular weight was 15,000.

<Synthesis of acid-decomposable compound graft polymer C> The synthesis of polymer B was performed in the same manner as in the synthesis of polymer B except that 38.85 g (0.20 mol) of tetraethylene glycol was used instead of 30.03 g of triethylene glycol. Polymer C was obtained. The obtained polymer was subjected to GPC by pullulan standard,
When measured with N, N-dimethylformamide solvent,
The weight average molecular weight was 15,000.

<Synthesis of Acid Decomposable Compound Graft Polymer D> A trunk polymer was synthesized in the same manner as for Polymer A. Next, 21.22 g (0.20 mol) of benzaldehyde,
After charging 27.63 g (0.20 mol) of phenyl cellosolve, ethanol as a reaction solvent used for radical polymerization is distilled off under reduced pressure. Then, 60 mg of p-toluenesulfonic acid is added, and the mixture is reacted at 100 ° C. for 1 hour in an oil bath. Next, the reaction temperature was raised to 150 ° C., and the reaction was carried out for 5 hours while distilling off water as a reaction by-product, to obtain an acid-decomposable compound graft polymer D. The obtained polymer was measured by GPC with a pullulan standard and N, N-dimethylformamide solvent to find that the weight average molecular weight was 10,000.

<Synthesis of acid-decomposable compound graft polymer E> An acid was prepared in the same manner as in the synthesis of polymer D except that 30.03 g (0.20 mol) of triethylene glycol was used instead of 27.63 g of phenyl cellosolve. A degradable compound graft polymer E was obtained. The obtained polymer was subjected to GPC.
The weight average molecular weight was 11,000 as measured with a pullulan standard and N, N-dimethylformamide solvent.

<Synthesis of acid-decomposable compound graft polymer F> An acid was prepared in the same manner as in the synthesis of polymer D except that 38.85 g (0.20 mol) of tetraethylene glycol was used instead of 27.63 g of phenyl cellosolve. A degradable compound graft polymer F was obtained. The obtained polymer was measured by GPC with a pullulan standard and an N, N-dimethylformamide solvent to find that the weight average molecular weight was 12,000.

When the vinyl polymer of the present invention is used together with a phenol resin, the mixing ratio of phenol resin / vinyl polymer of the present invention is preferably 95/5 to 20/80.

The vinyl polymer of the present invention may be used in combination with other known acid-decomposable compounds.
No. 89003, No. 51-120714, No. 53-1
No. 33429, No. 55-12959, No. 55-126
Compounds having a C--O--C bond described in JP-A Nos. 236 and 56-17345;
A compound having a Si-OC bond of No. 112446,
Other acid-decomposable compounds described in JP-A-60-3625 and JP-A-60-10247.
No. 246, compounds having a Si—N bond, carbonates described in JP-A-62-251743,
Ortho titanate described in 2-280841;
Orthosilicates described in JP-A-62-280842, acetals and ketals described in JP-A-63-10153, and C-forms described in JP-A-62-244030.
A compound having an S bond can be used.

In the present invention, the content of the acid-decomposable compound graft polymer is preferably in the range of 5 to 70% by weight, together with other acid-decomposable compounds, based on the total solid content of the photosensitive composition. It is preferably, particularly preferably, 10 to 50% by weight.

The photoacid generator used in the present invention includes:
For example, diazonium, phosphonium, sulfonium and iodonium BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆
^2-, ClO ₄ ^- salt, triazine and oxadiazole organic halogen compounds such as, orthoquinone - quinonediazide sulfonylchloride and can be used organic metal or the like, in principle, free-radical-forming optical All organic halogen compounds known as initiators are compounds that form hydrohalic acids and can be used as photoacid generators. Examples of the above compounds forming a hydrohalic acid are described in U.S. Pat. Nos. 3,515,552 and 3,536,489.
No. 3,779,778 and West German Offenlegungsschrift 2,243,621, and also, for example, West German Offenlegungsschrift 2,610,84.
The compound capable of generating an acid by photolysis described in No. 2 can also be used.

Further, JP-A-54-74728 and JP-A-55-74728.
No. 24113, No. 55-77742, No. 60-362
No. 6, 60-138538, for example, 2-trichloromethyl-5- [β (2-benzofuryl) vinyl]
2-halomethyl such as -1,3,4-oxadiazole
1,3,4-oxadiazole-based compounds can be used. Further, those described in JP-A-56-17345 and the o-naphthoquinonediazido-4-sulfonic acid halogenide described in JP-A-50-36209 can also be used.

In the present invention, a particularly preferred acid generator is a triazine or oxadiazole organic halide having a methyl trihalide group.

Specific examples of preferred acid generators are shown below, but are not limited thereto.

[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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The amount of the photoacid generator to be used can vary widely depending on its chemical properties and the composition and physical properties of the photosensitive composition. Suitably, the range is 1 to about 20% by weight, preferably 0.2 to 10% by weight.

As the infrared absorbing agent used in the photosensitive composition of the present invention, an infrared absorbing dye having absorption at a wavelength of 700 nm or more, carbon black, magnetic powder and the like can be used. Particularly preferred infrared absorbers are 700 to 850.
This is an infrared absorbing dye having an absorption peak at nm and a molar extinction coefficient ε at the peak of 10 ⁵ or more.

Examples of the infrared absorbing dye include cyanine dyes, squarium dyes, croconium dyes, azurenium dyes, phthalocyanine dyes, naphthalocyanine dyes, polymethine dyes, naphthoquinone dyes, and thiopyrylium dyes. Examples include dithiol metal complex dyes, anthraquino dyes, indoaniline metal complex dyes, and intermolecular CT dyes.

Further, as the infrared absorbing dye, JP-A-6
3-139191 and 64-33547, JP-A-1
-160683, 1-280750, 1-29
No. 3342, No. 2-2074, No. 3-26593,
3-30991, 3-34891, 3-36
Nos. 093, 3-36094, 3-36095,
The compounds described in JP-A-3-42281 and JP-A-3-103476 are exemplified.

Representative specific examples of the infrared absorbing dye preferably used in the present invention are shown below, but are not limited thereto.

[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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[0059]

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These dyes can be synthesized by a known method, but the following commercially available products can also be used.

Nippon Kayaku: IR750 (anthraquinone type); IR002, IR003 (aluminum type);
R820 (polymethine type); IRG022, IRG03
3 (diimmonium-based); CY-2, CY-4, CY-
9, CY-20 Mitsui Toatsu: KIR103, SIR103 (phthalocyanine-based); KIR101, SIR114 (anthraquinone-based); PA1001, PA1005, PA1006, S
IR128 (metal complex type) Dainippon Ink and Chemicals: Fastogen blue 812
0 Midori Kagaku: MI, R-101, 1011, 1021 Others are also commercially available from various companies such as Nippon Kogaku Dyestuffs, Sumitomo Chemical, Fuji Photo Film.

<< Photosensitive lithographic printing plate material >> The photosensitive layer of the photosensitive lithographic printing plate material of the present invention is formed by coating the photosensitive composition of the present invention, and a binder can be used. As the binder, for example, a high molecular weight binder can be used. Examples of the high molecular weight binder include a novolak resin, a polymer having a hydroxystyrene unit, a polymer having a structural unit represented by the following general formula (I), and other known acrylic resins.

Examples of the novolak resin include phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde copolycondensate resin described in JP-A-55-57841, and JP-A-55-127553. And a copolycondensate resin of p-substituted phenol and phenol or cresol and formaldehyde.

Examples of the polymer having a hydroxystyrene unit include polyhydroxystyrene and hydroxystyrene copolymer described in JP-B-52-41050.

[0065]

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In the formula, R ₁ and R ₂ are each a hydrogen atom,
Represents an alkyl group or a carboxyl group, and is preferably a hydrogen atom. R ₃ represents a hydrogen atom, a halogen atom or an alkyl group, preferably a hydrogen atom, a methyl group or an ethyl group. R ₄ represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and is preferably a hydrogen atom. B
Represents a phenylene group or a naphthylene group including those having a substituent; examples of the substituent include an alkyl group such as a methyl group and an ethyl group; a halogen atom such as a chlorine atom and a bromine atom; a carboxylic acid group; a methoxy group and an ethoxy group; An alkoxy group of
Examples thereof include a hydroxyl group, a sulfonic acid group, a cyano group, a nitro group, and an acyl group, and are preferably those having no substituent or substituted with a methyl group. A is an optionally substituted alkylene group connecting a nitrogen atom or an oxygen atom to an aromatic carbon atom, and m represents an integer of 0 to 10.

The monomer units which can be used in combination with the structural units represented by the above general formulas (I) to (V) include ethylenically unsaturated olefins such as ethylene, propylene, isobutylene, butadiene and isoprene. Styrene, α-methylstyrene, p-methylstyrene, p
Styrenes such as chlorostyrene; acrylic acids such as acrylic acid and methacrylic acid; unsaturated aliphatic dicarboxylic acids such as itaconic acid, maleic acid and maleic anhydride; methyl acrylate, ethyl acrylate and n-butyl acrylate , Isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-
Esters of α-methylene aliphatic monocarboxylic acids such as methyl chloroacrylate, methyl methacrylate and ethyl methacrylate; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide; acrylanilide, p-chloroacrylanilide; anilides such as m-nitroacrylanilide and m-methoxyacrylanilide; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl acetate; methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, β-chloroethyl vinyl ether and the like Vinyl ethers; vinyl chloride, vinylidene chloride,
Vinyl derivatives such as vinylidene cyanide; 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxycarbonylethylene, 1-methyl-1-nitroethylene and the like Ethylene derivatives; N-vinyl monomers such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidene, and N-vinylpyrrolidone. These vinyl monomers exist in a polymer compound in a structure in which an unsaturated double bond is cleaved. Of these, esters and nitriles of aliphatic monocarboxylic acids are preferred.

The polymer having the structural unit represented by the general formula (I) can be more specifically represented by, for example, (a) to (h).

[0069]

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In (a) to (h), R _{1 to} R ₅ each represent a hydrogen atom, an alkyl group or a halogen atom;
Represents an alkyl group or a halogen atom. Also, m, n,
1, k and s represent mol% of each structural unit.

A novolak resin, a polymer having a hydroxystyrene unit, and a polymer having a structural unit represented by the general formula (I) can be used in combination.

Further, in order to improve the oil sensitivity of the photosensitive layer,
Condensates of phenols and aldehydes substituted with an alkyl group having 3 to 15 carbon atoms described in JP-A-50-125806, t-butylphenol formaldehyde resin, etc.
A lipophilic resin can be added. If necessary, the photosensitive layer may contain other dyes, pigments, sensitizers and the like.

In applying the photosensitive composition of the present invention, a solvent that dissolves each component can be used, and propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl Cellosolve acetate, dimethylformamide, dimethylsulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, methyl ethyl ketone and the like can be mentioned. These solvents are used alone or in combination of two or more.

As the coating method, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating and curtain coating can be used. The amount of coating varies depending on the application, but as for the photosensitive lithographic printing plate material, it is 0.5 to 5.0 g as a solid content.
/ M ² is preferred.

The hydrophilic support on which the photosensitive layer is provided is made of a metal plate such as aluminum, zinc, steel, copper, etc .;
Metal plates, paper, plastic films and glass plates on which copper, nickel, aluminum, iron, etc. are plated or deposited,
Examples include paper coated with a resin, paper covered with a metal foil such as aluminum, and a plastic film subjected to a hydrophilic treatment. Of these, an aluminum plate is preferred. When applied to a photosensitive lithographic printing plate material, it is preferable to use, as the support, an aluminum plate that has been subjected to surface treatment such as graining treatment, anodic oxidation treatment and, if necessary, sealing treatment.

Examples of the graining method include a mechanical method and a method of etching by electrolysis.
Examples of the mechanical method include a ball polishing method, a brush polishing method, a polishing method using liquid honing, and a buff polishing method. The various methods described above can be used alone or in combination depending on the composition of the aluminum material and the like.

For etching by electrolysis, phosphoric acid,
It is carried out using a bath in which inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid are used alone or in combination of two or more. After the graining treatment, if necessary, a desmut treatment is performed with an aqueous solution of an alkali or an acid to neutralize and wash with water.

The anodic oxidation treatment is carried out by using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid or the like as an electrolytic solution, and using an aluminum plate as an anode for electrolysis. The amount of anodic oxide film formed is 1 to 50 m
g / dm ² is suitable, and preferably 10 to 40 mg / g.
dm ² , particularly preferably 25 to 40 mg / dm ² . The amount of the anodic oxide film is determined, for example, by immersing the aluminum plate in a chromic phosphate bath solution (prepared by dissolving 35 g of phosphoric acid 85% solution and 20 g of chromium (IV) oxide in 1 liter of water) to dissolve the oxide film. It is determined from the weight change measurement before and after dissolution of the coating on the plate.

Examples of the sealing treatment include boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment and the like. In addition, the aluminum plate support may be subjected to an undercoating treatment with an aqueous solution of a water-soluble polymer compound or a metal salt such as fluorinated zirconic acid.

<< Image Forming Method >> When the photosensitive lithographic printing plate material of the present invention contains a dye having absorption in the infrared region, image exposure can be performed using a light source having a wavelength of 700 nm or more. As a light source, a semiconductor laser, He-N
e laser, YAG laser, carbon dioxide laser and the like. The output is suitably 50 mW or more, preferably 100 mW or more.

As a developer used for development, an aqueous alkaline developer is preferable. The aqueous alkali developer includes, for example, aqueous solutions of alkali metal salts such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, dibasic sodium phosphate, and tertiary sodium phosphate. . The concentration of the alkali metal salt is preferably used in the range of 0.05 to 20% by weight, more preferably 0.1 to 10% by weight.

Anionic solvents, amphoteric surfactants and organic solvents such as alcohols can be added to the developer as required. As the organic solvent, propylene glycol, ethylene glycol monophenyl ether, benzene alcohol, n-propyl alcohol and the like are useful.

[0083]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1 (Preparation of Support) A 0.24 mm-thick aluminum plate (material: 1050, tempered H16) was degreased in a 3% JIS No. 3 sodium silicate aqueous solution, and then in a 1% hydrochloric acid aqueous solution. The temperature was 25 ° C., the current density was 80 A / dm ² , and the amount of electricity was 400 C / dm ² . After washing with water, anodizing treatment is performed in a 30% sulfuric acid solution to form a film of 3 g / m ² , and further, a hydrophilic treatment is performed for 20 seconds with a 0.5% aqueous solution of sodium silicate at 85 ° C. for photosensitive lithographic printing. An aluminum support for the plate material was prepared.

(Preparation of photosensitive lithographic printing plate material) A photosensitive composition coating solution having the following composition was applied to an aluminum support using a wire bar, dried at 80 ° C. for 4 minutes, and dried to a film thickness of 2.0 mg / mm. A dm ² photosensitive layer was formed.

<Photosensitive Composition Coating Solution-1> 45 g of acid-decomposable compound graft polymer A 50 g of novolak resin [phenol / m-cresol / p-cresol: molar ratio 5/57/38 weight average molecular weight 3700] S- Triazine 4 g Infrared absorbing dye 1 g [Nippon Kayaku Co., Ltd .: CY-10] Propylene glycol monomethyl ether 150 ml Methyl ethyl ketone 50 ml Instead of acid-decomposable compound graft polymer A, the same polymers B to
Except for using F, the photosensitive composition coating solution-2 to
6 was prepared.

<Photosensitive Composition Coating Solution-7> Acid-decomposable compound graft polymer A 40 g Acid-decomposable compound a 15 g [0.5 mol of cyclohexanone, 1.0 mol of phenyl cellosolve and 80 mg of p-toluenesulfonic acid were stirred. The reaction was carried out at 100 ° C. for 1 hour while gradually increasing the temperature to 150 ° C., and further reacted at 150 ° C. for 4 hours. Methanol generated by the reaction was distilled off during this period. After cooling, 500 ml of tetrahydrofuran and 2.5 g of anhydrous potassium carbonate were added, followed by stirring and filtration. The solvent was distilled off from the filtrate under reduced pressure, and the low-boiling components were further distilled off at 150 ° C. under a high vacuum to obtain a viscous oily acid-decomposable compound a. ]

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Novolak resin [supra] 40 g S-triazine 4 g infrared absorbing dye [supra] 1 g propylene glycol monomethyl ether 150 ml methyl ethyl ketone 50 ml acid-decomposable compound graft polymer A in place of graft polymer A,
Coating solution-8 of the photosensitive composition, except that C was used.
9 was prepared.

<Photosensitive Composition Coating Solution-10> Acid-decomposable compound a 15 g Novolak resin [supra] 80 g S-triazine 4 g infrared absorbing dye [supra] 1 g propylene glycol monomethyl ether 150 ml methyl ethyl ketone 50 ml (developability Evaluation) The prepared photosensitive lithographic printing plate material-1
Each of 10 was subjected to solid exposure of 10 cm × 10 cm using an infrared laser of 830 nm in oscillation wavelength and 500 mW, and was immersed in a developer having the following composition at 30 ° C. for 30 seconds. The required amount of energy was calculated.

<Developer Composition to pH 12.7> Potassium A-silicate 1160 g Potassium hydroxide 133 g Pure water 5133 ml (Evaluation of printing durability) And developed. Printing was performed using a printing machine manufactured by Heidel Co., Ltd .: GTO and printing ink manufactured by Toyo Ink Co., Ltd .: High Echo Red, and the number of sheets until a defect occurred on the printed matter was evaluated.

The results are shown below.

Exposure energy amount Number of prints Remarks (mJ / cm ² ) (sheets) Material-1 120 120,000 Present material-2 110 100,000 Present material-3 115 105,000 Present material-4 120 130,000 Inventive Material-5 110 115,000 Inventive Material-6 115 120,000 Inventive Material-795 100,000 Inventive Material-890 90,000 Inventive Material-9 90 90,000 Inventive Material-10 140 35,000 Comparison

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As demonstrated in the examples, according to the present invention, excellent developability and printing durability can be obtained in a system using a combination of a photoacid generator and an acid-decomposable compound.

Claims (9)

[Claims] 1. A photosensitive composition comprising a vinyl polymer having in its side chain a graft group formed from at least one selected from an orthocarboxylic acid ester, an acetal and a ketal. 2. The vinyl polymer according to claim 1, wherein the vinyl polymer has an aliphatic hydroxyl group in a side chain and the graft group is introduced into the aliphatic hydroxyl group. Photosensitive composition. 3. The photosensitive composition according to claim 2, wherein the graft group is represented by the following general formula (1). Embedded image [Wherein, R ₁ and R ₂ each represent a hydrogen atom and a carbon number of 1 to 12;
Represents an alkyl group or an aryl group having 6 to 18 carbon atoms,
These may combine with each other to form a ring. R ₃ represents an alkylene group having 1 to 6 carbon atoms; R ₄ represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 18 carbon atoms;
Represents CONH-, -COO- or -O-, and 1 is 1 or 0. ] 4. The photosensitive composition according to claim 1, wherein the graft group is a polyacetal or a polyketal represented by the following general formula (2). Embedded image [Wherein, R _{1 to} R ₃ have the same meanings as those of the general formula (1);
m represents an integer of 1 to 6, and n represents an integer of 1 to 200. ] 5. The photosensitive composition according to claim 1, further comprising a photoacid generator. 6. The photosensitive composition according to claim 5, wherein the photoacid generator has a methyl trihalide group. 7. The photosensitive composition according to claim 5, comprising a dye having an absorption in an infrared region. 8. A photosensitive lithographic printing plate material formed by applying the photosensitive composition according to claim 5 on a hydrophilic surface of a hydrophilic support. 9. An image forming method, comprising: exposing the photosensitive lithographic printing plate material according to claim 8 to infrared rays; and removing an exposed portion with an alkaline developer.