JPH07333835A - Photosensitive composition and photosensitive lithographic printing plate - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a photosensitive composition and a photosensitive lithographic printing plate which have excellent dot reproducibility and exposure visible imageability without lowering sensitivity. A photosensitive composition containing an o-quinonediazide compound and a photobleachable colored complex of spiropyran and a metal salt.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive composition and a photosensitive lithographic printing plate.

[0002]

BACKGROUND OF THE INVENTION A photosensitive lithographic printing plate is one in which a photosensitive layer is provided on a hydrophilic support. For example, in a positive type photosensitive lithographic printing plate, an actinic ray such as ultraviolet rays is provided on the hydrophilic support. An ink-receptive photosensitive layer that is solubilized by exposure to is formed.

Usually, an o-quinonediazide compound is used as a photosensitive component in the photosensitive layer of a positive type photosensitive lithographic printing plate. In addition, an alkali-soluble resin is usually used in combination as a component for increasing the film strength and alkali-solubility.

As the above-mentioned o-quinonediazide compound,
1,2-naphthoquinone-2-diazide-5-sulfonic acid ester compounds and 1,2-naphthoquinone-2-diazide-4-sulfonic acid ester compounds are generally used as useful compounds, and particularly, pyrogallol and aldehydes. Alternatively, an ester compound with a polycondensation resin with a ketone or the like is preferably used.

In such a positive-working photosensitive lithographic printing plate, when the photosensitive layer is imagewise exposed and then developed, the ink-receptive photosensitive layer in the exposed area is removed and the surface of the hydrophilic support is exposed. On the other hand, the non-exposed portion of the photosensitive layer which is ink-receptive remains on the support to form an ink-receptive layer. In lithographic printing, the difference in the property that the exposed portion is hydrophilic and the unexposed portion is lipophilic is used.

Image exposure of the photosensitive layer is carried out by bringing a positive original film into close contact with a positive type photosensitive lithographic printing plate and irradiating it with ultraviolet rays. Also, while the ultraviolet rays reach the photosensitive layer, light scattering occurs, the light wraps around to the non-image area, and the area that should be the unexposed area is also exposed to light, resulting in a decrease in halftone dots. Light scattering also occurs due to the thickness of the photosensitive layer, and if the adhesion between the original film and the photosensitive layer is insufficient, the light scattering is further increased, and reproducibility of small dots is significantly deteriorated.

As a technique for improving the reproducibility of small dots due to the scattering of light, Japanese Patent Publication No. 5-70813 discloses a method in which a yellow dye is subbed under a photosensitive composition and unexposed by ultraviolet rays at the time of exposure. It is described that the halation of the photosensitive lithographic printing plate is prevented.However, the yellow dye present on the photosensitive lithographic printing plate absorbs ultraviolet rays even in the exposed part, which reduces the sensitivity of the photosensitive lithographic printing plate. Will occur.

In order to improve workability, the photosensitive lithographic printing plate should have a high color density difference between the exposed and unexposed areas so that the exposed areas become clear (exposure visible). Image quality) is required, but when a yellow dye is present in the photosensitive lithographic printing plate, the yellow dye remains in both the exposed and unexposed areas, resulting in a high color density between the exposed and unexposed areas. No difference can be obtained, and the visibility of exposure image is deteriorated.

Techniques for improving the visibility of exposure are known. For example, in JP-A-55-32070, an interaction between an s-triazine compound and a photolysis product of the s-triazine compound is known. It is described that an exposure visible image property is obtained by using a color-changing agent that changes the color tone by doing so. If an s-triazine compound used here is colored yellow, the light scattering can be prevented, but the sensitivity of the photosensitive lithographic printing plate is lowered as in the technique using the yellow dye. I will let you.

Therefore, there is a demand for a technique for obtaining a photosensitive lithographic printing plate which prevents light scattering without lowering the sensitivity, obtains a good reproducibility of small dots, and does not impair the visibility of exposed image. It was

[0011]

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide a photosensitive composition and a photosensitive lithographic printing plate which have excellent dot reproducibility and exposure visual imageability without lowering the sensitivity.

[0012]

The above object of the present invention is to provide a photosensitive composition containing (1) an o-quinonediazide compound and a photobleachable colored complex of spiropyran and a metal salt. (2) The photosensitive composition as described in (1) above, wherein the photobleachable colored complex composed of spiropyran and a metal salt has a maximum light absorption wavelength at 340 to 450 nm. (3) The photosensitive composition as described in (1) or (2) above, wherein the photosensitive composition contains an alkali-soluble resin. (4) A photosensitive lithographic printing plate comprising a support and a layer comprising the photosensitive composition as described in (1) to (3) above. (5) A support is provided with an undercoat layer containing a photobleaching colored complex of spiropyran and a metal salt, and then a layer of a photosensitive composition containing an o-naphthoquinonediazide compound is provided. Photosensitive lithographic printing plate. (6) Photosensitivity, characterized in that after a layer of a photosensitive composition containing an o-quinonediazide compound is provided on a support, a layer containing a photobleachable colored complex of spiropyran and a metal salt is provided. Planographic printing plate. (7) The photosensitive lithographic printing plate as described in (5) or (6) above, wherein the layer of the photosensitive composition containing the o-naphthoquinonediazide compound contains an alkali-soluble resin. (8) The photosensitive lithographic printing plate as described in (5) to (7) above, wherein the photobleachable colored complex consisting of spiropyran and a metal salt has a maximum light absorption wavelength at 340 to 450 nm. Can be achieved by

The present invention will be described in detail below.

First, the photobleachable colored complex consisting of spiropyran and a metal salt contained in the photosensitive composition of the present invention and the constituent layers of the photosensitive lithographic printing plate of the present invention will be described.

The photobleachable colored complex of spiropyran of the present invention and a metal salt can be obtained by a complex forming reaction of spiropyran and a metal salt.

Examples of the spiropyran used for forming the photobleachable coloring complex include spirodibenzopyran, spirodinaphthopyran, spirobenzonaphthopyran, 1,
3,3-trimethylindolinobenzospiropyran,
1,3,3-Trimethylindolinonaphthospiropyran and the like can be mentioned. These spiropyrans may be substituted.

Particularly preferred spiropyrans in the present invention are represented by the following general formulas [I] to [V].

[0018]

[Chemical 1]In the general formulas [I] to [V], R, R₁,
R ₁′, R₂, R ₂′, R₃, R ₃′ Is hydrogen source
Child, aliphatic group (eg, methyl group, ethyl group, propyl
Group, amyl group, hexadecyl group), halogen-substituted alkyl
Group, halogen atom, nitro group, hydroxy group, alcohol
Xy group, aryloxy group, phenyl group or substituted group
Phenyl group, piperidyl group, alkylene ester group,
Xylene carboxyl group, carbamide group or substituted calcium
Represents a bamide group.

Examples of the metal salt forming the photobleachable colored complex of spiropyran and a metal salt include halides of copper, nickel, cobalt, lead, zinc, tin, mercury, antimony, bismuth, barium, molybdenum and tungsten. , Nitrates, sulfates, acetates, salicylates, benzoates, stearates, behenates and naphthenates are preferably used.

In order to stabilize the colored state of the complex consisting of spiropyran and a metal salt, it is possible to use an activated metal oxide described in JP-B-55-44935 as a semiconductive adsorbent. preferable.

The photoabsorption maximum wavelength of the photobleachable colored complex consisting of spiropyran and a metal salt is preferably in the range of 340 to 450 nm.

As the colored complex consisting of spiropyran having a maximum light absorption wavelength in the range of 340 to 450 nm and a metal salt, for example, 1,3,3-trimethylnitro-spiro (2'H-1'-benzopyran-2, 2'-Indoline) and tin chloride complex, 3,3'-dimethyl-6'-nitro-spiro (2'H-1-benzopyran-2,2'-
Benzoxazole) and zinc chloride complex, 3-methyl-
6-nitro-spiro (2H-1-benzopyran) -2,
A complex of 2 '(2'H-1'-beta naphthopyran) and antimony trichloride can be mentioned.

Next, the o-quinonediazide compound used in the photosensitive composition of the present invention or the photosensitive composition layer of the photosensitive lithographic printing plate of the present invention will be described.

The orthoquinonediazide compound is a compound having an orthoquinonediazide group in the molecule, and the orthoquinonediazide compound which can be used in the present invention is not particularly limited, and examples thereof include o-naphthoquinonediazide compounds, Examples thereof include ester compounds of a polycondensation resin of o-naphthoquinonediazide sulfonic acid with phenols and aldehydes or ketones.

Examples of the phenols in the polycondensation resin with the above-mentioned phenols and aldehydes or ketones include phenol, o-cresol, m-cresol,
Examples include monohydric phenols such as p-cresol, 3,5-xylenol, carvacrol, thymol, dihydric phenols such as catechol, resorcin, and hydroquinone, and trihydric phenols such as pyrogallol and phloroglucin. Examples of the aldehyde include formaldehyde,
Examples thereof include benzaldehyde, acetaldehyde, crotonaldehyde, furfural and the like. Of these, preferred are formaldehyde and benzaldehyde. Examples of ketones include acetone and methyl ethyl ketone.

Specific examples of polycondensation resins with phenols and aldehydes or ketones include phenol-formaldehyde resin, m-cresol-formaldehyde resin, m- and p-mixed cresol-formaldehyde resin, resorcin-benzaldehyde resin, Examples include pyrogallol / acetone resin.

In the o-naphthoquinonediazide compound, the condensation rate (reaction rate for one OH group) of o-naphthoquinonediazide sulfonic acid with respect to the OH groups of phenols is preferably 15% to 80%, more preferably 2
It is 0% to 45%.

Further, as the orthoquinonediazide compound used in the present invention, the following compounds described in JP-A-58-43451 can also be mentioned. That is, for example, 1,2-benzoquinone diazide sulfonic acid ester, 1,2-naphthoquinone diazide sulfonic acid ester, 1,2-benzoquinone diazide sulfonic acid amide,
Known 1,2-quinonediazide compounds such as 1,2-naphthoquinonediazide sulfonic acid amide, and more specifically, J. Kosar "Light-Sensitive Systems" No. 339. Pp. 352 (1965), John Willie
And Sons (John Willey & Sons) (New York) and W S De Forest (WSDe F)
1,2-benzoquinonediazide-4-sulfonic acid phenyl ester, 1, described in "Photoresist", Vol. 50 (1975), McGraw Hill, Inc. (New York).
2,1 ′, 2′-di- (benzoquinonediazide-4-sulfonyl) -dihydroxybiphenyl, 1,2-benzoquinonediazide-4- (N-ethyl-N-β-naphthyl) -sulfonamide, 1,2- Naphthoquinonediazide-5-sulfonic acid cyclohexyl ester, 1- (1,
2-naphthoquinonediazide-5-sulfonyl) -3,5
-Dimethylpyrazole, 1,2-naphthoquinonediazide-5-sulfonic acid-4'-hydroxydiphenyl-4 '
-Azo-β-naphthol ester, N, N-di- (1,
2-naphthoquinonediazide-5-sulfonyl) -aniline, 2 '-(1,2-naphthoquinonediazide-5-sulfonyloxy) -1-hydroxy-anthraquinone,
1,2-naphthoquinonediazide-5-sulfonic acid-2,
4-dihydroxybenzophenone ester, 1,2-naphthoquinonediazide-5-sulfonic acid-2,3,4-trihydroxybenzophenone ester, 1,2-naphthoquinonediazide-5-sulfonic acid chloride 2 mol and 4,
Condensate with 1 mol of 4'-diaminobenzophenone, 1,
2-naphthoquinonediazide-5-sulfonic acid chloride 2
, A condensate of 1,4'-dihydroxy-1,1'-diphenylsulfonic acid 1 mol, a condensate of 1,2-naphthoquinonediazide-5-sulfonic acid chloride 1 mol and purpurogallin 1 mol, 1,2 -Naphthoquinone diazide-
A 1,2-quinonediazide compound such as 5- (N-dihydroabietyl) -sulfonamide can be exemplified. In addition, Japanese Examined Patent Publications No. 37-1953 and 37-3627
Nos. 37-13109, 40-26126, 40-3801, 45-5604, 45-27.
No. 345, No. 51-13013, JP-A-48-965.
The 1,2-quinonediazide compounds described in JP-A No. 75, 48-63802 and 48-63803 can also be mentioned.

Of the above orthoquinonediazide compounds,
An o-quinone diazide ester compound obtained by reacting 1,2-benzoquinone diazide sulfonyl chloride or 1,2-naphthoquinone diazide sulfonyl chloride with pyrogallol-acetone condensation resin or 2,3,4-trihydroxybenzophenone is particularly preferable.

In the present invention, as the orthoquinonediazide compound, the above compounds may be used alone or in combination of two or more kinds.

The content of the orthoquinonediazide compound in the photosensitive composition is preferably 5 to 60% by weight, and particularly preferably 10 to 50% by weight.

To the photosensitive composition forming the photosensitive layer of the present invention, it is preferable to further add an alkali-soluble resin in order to enhance film strength and alkali solubility.

The alkali-soluble resin that can be used in the present invention is not particularly limited, and examples thereof include novolac resins, vinyl polymers having a phenolic hydroxyl group, and those described in JP-A-55-57841. Examples thereof include condensation resins of polyphenols with aldehydes or ketones.

Examples of the novolak resin which can be used in the present invention include phenol / formaldehyde resin, cresol / formaldehyde resin, JP-A-55.
-57841, a phenol-cresol-formaldehyde copolymer resin, as described in JP-A-55-127553.
Copolymer resins of substituted phenol and phenol or cresol and formaldehyde can be used.

The molecular weight (polystyrene standard) of the novolak resin is preferably 3.00 × 10 in terms of number average molecular weight Mn.
^{2 to} 7.50 × 10 ³ , weight average molecular weight Mw of 1.00 ×
10 ^{3 to} 3.00 × 10 ⁴ , more preferably Mn of 5.0
0 × 10 ^{2 to} 4.00 × 10 ³ , Mw of 3.00 × 10 ^3.
˜2.00 × 10 ⁴ .

The above novolak resins may be used alone or in combination of two or more kinds.

The novolac resin is contained in the photosensitive composition in an amount of 5 to 9
It is preferable to contain 5% by weight.

The vinyl polymer having a phenolic hydroxyl group is a polymer having a unit having a phenolic hydroxyl group in its molecular structure, and is represented by the following general formula [VI]
A polymer containing at least one structural unit represented by [X] is preferable.

[0039]

[Chemical 2]

In the general formulas [VI] to [X], R
₁ and R ₂ each represent a hydrogen atom, an alkyl group or a carboxyl group, and preferably a hydrogen atom. R
₃ represents a hydrogen atom, a halogen atom or an alkyl group,
Preferred is a hydrogen atom or an alkyl group such as a methyl group and an ethyl group. R ₄ represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and preferably a hydrogen atom. A represents an optionally substituted alkylene group that connects a nitrogen atom or an oxygen atom and an aromatic carbon atom, m represents an integer of 0 to 10, and B represents a substituent. Represents a phenylene group which may be substituted or a naphthylene group which may have a substituent.

The vinyl polymer having a phenolic hydroxyl group used in the present invention preferably has a copolymer type structure having the structural units represented by the general formulas [VI] to [X]. As the monomer to be copolymerized,
For example, ethylene, propylene, isobutylene, butadiene, isoprene and other ethylenically unsaturated olefins,
For example, styrenes such as styrene, α-methylstyrene, p-methylstyrene, and p-chlorostyrene, for example,
Acrylic acids such as acrylic acid and methacrylic acid, for example,
Itaconic acid, maleic acid, unsaturated aliphatic dicarboxylic acids such as maleic anhydride, for example, methyl acrylate, ethyl acrylate, acrylate n-butyl, isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate, Phenyl acrylate, α-methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, esters of α-methylene aliphatic monocarboxylic acid such as ethyl ethacrylate, for example, acrylonitrile, nitriles such as methacrylonitrile, for example, acrylamide. Amides such as, for example, acrylanilide, p-chloroacrylanilide, m-nitroacrylanilide, m-
Anilides such as methoxyacrylanilide, for example, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl esters such as vinyl acetate, for example, methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, vinyl ethers such as β-chloroethyl vinyl ether, Vinyl chloride, vinylidene chloride, vinylidene cyanide, for example, 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxycarbonylethylene, 1-methyl-1-nitro Ethylene derivatives such as ethylene, for example, N-vinyl-based monomers such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidene and N-vinylpyrrolidone. These monomers are present in the polymer compound in a structure in which the unsaturated double bond is cleaved.

Of the above-mentioned monomers, aliphatic monocarboxylic acid esters and nitriles exhibit excellent performance for the purpose of the present invention and are preferred.

These monomers may be bound to the polymer used in the present invention in either a block or random state.

The vinyl polymer having a phenolic hydroxyl group is preferably contained in the photosensitive composition in an amount of 0.5 to 70% by weight.

As the vinyl polymer having a phenolic hydroxyl group, the above polymers may be used alone or in combination of two or more kinds. It can also be used in combination with other polymer compounds.

The photosensitive composition containing the o-quinonediazide compound of the present invention, the alkali-soluble resin and the photobleachable color complex composed of spiropyran and a metal salt is a photosensitive composition containing a photobleachable color complex composed of spiropyran and a metal salt. It is preferable to contain 0.2% to 10% with respect to the total solid content in the composition.

A photosensitive composition containing the o-quinonediazide compound of the present invention, an alkali-soluble resin and a photobleachable colored complex of spiropyran and a metal salt, and a photosensitive composition containing the o-naphthoquinonediazide compound and an alkali-soluble resin. The composition is applied with a coating solution prepared by dissolving or dispersing these in a solvent and drying the composition to form a photosensitive layer.

Examples of the solvent that can be used for dissolving the photosensitive composition include, for example, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl. Ether, diethylene glycol diethyl ether, diethylene glycol monoisopropyl ether, propylene glycol, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl ethyl ether, ethyl formate, propylic acid formate , Butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate,
Examples thereof include ethyl butyrate, dimethylformamide, dimethylsulfoxide, dioxane, acetone, methylethylketone, cyclohexanone, methylcyclohexanone, diacetone alcohol, acetylacetone, and γ-butyrolactone. These solvents may be used alone or in admixture of two or more.

The coating method used for coating the photosensitive composition is a conventionally known method, for example, spin coating, wire bar coating, dip coating, air knife coating, spray coating, air spray coating, electrostatic air spray. Methods such as coating, roll coating, blade coating and curtain coating are used. At this time, the coating amount depends on the application,
For example, a coating amount of 0.05 to 5.0 g / m ² is preferable as the solid content.

A photosensitive composition containing the o-quinonediazide compound of the present invention, an alkali-soluble resin and a photobleachable coloring complex composed of spiropyran and a metal salt, and a photosensitive composition containing the o-naphthoquinonediazide compound and an alkali-soluble resin. To the composition, a visible image forming agent capable of forming a visible image by exposure can be added in order to enhance the visible image exposure property.

The visible agent is composed of a compound which forms an acid or a free radical upon exposure and an organic dye which changes its color tone by interacting with the generated acid or a free radical. Examples of the compound that produces the compound include, for example, o-naphthoquinonediazide-4-sulfonic acid halogenide described in JP-A-50-36209, trihalomethyl-2-pyrone and trihalogen described in JP-A-53-36223. Methyl-triazine, ester compound or amide compound of o-naphthoquinonediazide-4-sulfonic acid chloride described in JP-A-55-6244 and a phenol or aniline having an electron-withdrawing substituent, JP-A-55- 77742
Examples thereof include halomethylvinyloxadiazole compounds and diazonium salts described in JP-A No. 57-148784 and the like, and as the organic dye,
For example, Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.), Patent Pure Blue (Sumitomo Mikuni Chemical Co., Ltd.), Oil Blue # 603 (Orient Chemical Co., Ltd.), Sudan Blue II (BASF), Crystal violet, malachite green, fuchsin,
Methyl violet, ethyl violet, methyl orange, brilliant green, congo red, eosin, rhodamine 66 and the like can be mentioned.

The visible image agents described in JP-A-55-3207 and JP-A-60-88942 can be preferably used in the present invention.

Further, a photosensitive composition containing the o-quinonediazide compound of the present invention, an alkali-soluble resin and a photobleaching colored complex of spiropyran and a metal salt, and an o-naphthoquinonediazide compound and an alkali-soluble resin are contained. The photosensitive composition, in addition to the above materials,
If necessary, a plasticizer, a surfactant, an organic acid, an acid anhydride and the like can be added.

Further, a photosensitive composition containing the o-quinonediazide compound of the present invention, an alkali-soluble resin and a photobleachable colored complex of spiropyran and a metal salt, and an o-naphthoquinonediazide compound and an alkali-soluble resin are contained. In order to improve the oil sensitivity of the photosensitive composition, for example, p-tert-butylphenolformaldehyde resin, pn-octylphenolformaldehyde resin or these resins may be used in the photosensitive composition.
A resin partially esterified with a quinonediazide compound may be added.

Spiropyran and a metal provided after forming an undercoat layer containing a photobleachable colored complex of spiropyran and a metal salt of the present invention and a layer of a photosensitive composition containing an o-quinonediazide compound and an alkali-soluble resin A layer containing a photobleachable coloring complex consisting of a salt, a photobleaching coloring complex consisting of the spiropyran and a metal salt,
It can be formed by applying a coating liquid dissolved or dispersed in water, an organic solvent, or a solvent such as a mixed solvent of water and an organic solvent.

Preferred solvents in the present invention are water, hydrocarbon solvents and alcohol solvents, and the coating liquid is
It is preferable that a photobleachable colored complex consisting of spiropyran and a metal salt is dispersed and formed in these solvents or a mixed solvent of these solvents. A ball mill, a sand grinder, a roll mill, a homogenizer, a three roll method, a high pressure homogenizer, an ultra disperser, a bubble homogenizer, or the like can be used to disperse the photobleaching colored complex of spiropyran and a metal salt.

A surfactant or the like can be added to the coating liquid as a dispersant, and if necessary, a water-soluble polymer compound or the compound described in JP-B-5-70813 can be added. You can

As the coating method, the coating method described above can be used. Further, a dispersion coating method using an air spray method, an airless spray method, an electrostatic air spray method, an electrostatic atomization electrostatic coating method, or the like for coating the dispersion liquid (see JP-A-57-24558). Can be used.

When the layer containing the photobleachable color complex composed of spiropyran and a metal salt is an undercoat layer, the coating amount of the photobleachable color complex composed of spiropyran and a metal salt is such that the reflection optical density is a dye in a colored state. Is preferably 0.08 to 0.4 higher than when not applied, and the amount is preferably 0.5 g / m ² or less.

When the optical density is too high, the sensitivity is lowered, and when it is applied in an amount of more than 0.5 g / m ² , the printing durability is deteriorated, which is not preferable.

When a layer containing a photobleaching colored complex consisting of spiropyran and a metal salt is provided on the layer of a photosensitive composition containing an o-quinonediazide compound and an alkali-soluble resin, the layer containing spiropyran and a metal salt is used. The coating amount of the photobleachable coloring complex is preferably 0.08 to 0.4 higher than that when the upper layer is not provided in the colored state, and the amount is 0. 05
The range from g to 5 g / m ² is preferred.

Next, the support used in the photosensitive lithographic printing plate of the present invention will be described.

The support preferably has flexibility so that it can be set in an ordinary printing machine and can withstand a load applied during printing. For example, a metal plate of aluminum, magnesium, zinc, chromium, iron, copper, nickel or the like, An alloy plate of these metals, or a metal plate coated with chromium, zinc, copper, nickel, aluminum, iron or the like by plating or vapor deposition can be used. Of these, the support is preferably one using aluminum or its alloy.

Various kinds of aluminum alloys can be used, for example, silicon, copper, manganese, magnesium,
Examples include alloys of metals such as chromium, zinc, lead, bismuth, and nickel with aluminum.

The support made of aluminum or its alloy or the like is usually subjected to a degreasing treatment prior to the graining treatment in order to remove oil and fat components such as rolling oil adhering to the surface of the support. As the degreasing treatment, degreasing treatment using a solvent such as trichlene and thinner, emulsion degreasing treatment using an emulsion of kesilon and triethanol, and the like are used. In addition, an alkaline aqueous solution such as caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, it is possible to remove stains and oxide films which cannot be removed only by the above degreasing treatment.

The graining treatment of the present invention is a so-called mechanical surface-roughening method of mechanically roughening the surface, a so-called chemical surface-roughening method of chemically selectively surface-melting and roughening the surface, and electrochemical. The surface can be roughened by a known method such as a so-called electrochemical roughening method.

Mechanical graining methods include, for example, ball polishing, brush polishing, blast polishing, buff polishing, etc., and electrochemical graining methods include hydrochloric acid, nitric acid, etc. There is a method of electrolytically treating with an alternating current or a direct current in an electrolytic solution containing the same.

The graining treatment of the present invention can be carried out by any one of these methods or by using two or more methods in combination.

Since smut is formed on the surface of the support obtained by the graining treatment, it is generally preferable to appropriately perform washing with water or alkali etching in order to remove the smut. Examples of such a treatment include the alkali etching method described in Japanese Patent Publication No. 48-28123 and JP-A No. 53-12739.
Examples thereof include a treatment method such as a sulfuric acid desmutting method described in Japanese Patent Publication No. 1994-242242.

The support treated as described above is then anodized. Wear resistance due to anodizing treatment,
The chemical resistance and water retention can be improved. A known method can be used for the anodizing treatment. For example, a method of electrolyzing at a current density of 1 to 10 A / dm ² using an aqueous solution containing sulfuric acid and / or phosphoric acid or the like at a concentration of 10 to 50% is used. Preferably used, but in addition to US Pat.
A method of electrolyzing in sulfuric acid at a high current density, which is described in US Pat. No. 3,511,661.
It is also possible to use the method of electrolyzing with phosphoric acid described in the specification.

The anodized support may be sealed if necessary. These sealing treatments can be performed by using known methods such as hot water treatment, boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment, and nitrite treatment.

It is preferable that the support is further provided with a hydrophilic layer. For the formation of the hydrophilic layer, US Pat.
Alkali metal silicates described in US Pat. No. 1,461, hydrophilic celluloses described in US Pat. No. 1,860,426, JP-A-60-149491 and JP-A-63.
-165183 gazette amino acid and its salt,
Hydroxyl group-containing amines and salts thereof described in JP-A-60-232998, phosphates described in JP-A-62-19494, and monomers having a sulfo group described in JP-A-59-101651. A polymer compound containing a unit can be used.

The positive-working photosensitive lithographic printing plate of the present invention can be made into a plate by exposing and developing it in a usual manner. For example, a transparent original image having a line image, a halftone dot image, etc. is brought into close contact with the photosensitive surface for exposure, and then the photosensitive layer in the non-image area is removed using an appropriate developing solution to obtain a relief image. .

Suitable light sources for exposure include mercury lamps, metal halide lamps, xenon lamps, chemical lamps,
Examples include carbon arc lamps. The developer used for development is preferably an aqueous alkali solution, and examples thereof include alkali metal silicates such as sodium silicate and potassium silicate, sodium hydroxide, potassium hydroxide, sodium triphosphate, and dibasic sodium phosphate. An aqueous alkaline solution such as an aqueous solution of sodium carbonate, potassium carbonate or the like can be used. The concentration of the alkaline aqueous solution at this time varies depending on the type of the photosensitive composition and the alkali,
Generally, a range of 0.1 to 10% by weight is suitable. Also,
If necessary, an organic solvent such as a surfactant or alcohol may be added to the alkaline aqueous solution.

[0075]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 [Preparation of support] An aluminum plate (material 1050, temper H16) having a thickness of 0.24 mm was degreased for 1 minute in a 5 wt% sodium hydroxide aqueous solution kept at 60 ° C. After that, it was washed with water, neutralized, and washed with water again. Then, in an aqueous solution containing 0.5 mol of hydrochloric acid in 1 liter,
The electrolytic etching treatment was performed under the conditions of a temperature of 25 ° C., a current density of 60 A / dm ² and a treatment time of 60 seconds. Then 5% by weight
After desmutting treatment at 60 ° C. for 10 seconds in an aqueous solution of sodium hydroxide, the temperature is set to 2% in a 20 wt.
Anodization treatment was performed under the conditions of 0 ° C., current density 3 A / dm ² , and treatment time 1 minute, and hot water sealing treatment was further performed with hot water at 80 ° C. for 20 seconds to prepare a support.

[Application of Photosensitive Composition Coating Liquid] The following photosensitive composition coating liquid was applied to the above support using a wire bar and dried at 90 ° C. for 1 minute to prepare a photosensitive lithographic printing plate sample 1 .About.2 and photosensitive lithographic printing plate comparison samples 1 and 2 were obtained. At this time, the coating amount of the photosensitive composition was 2.
It was set to 2 g / m ² .

<Photosensitive Composition Coating Liquid> Sample 1 (1) Novolac resin (phenol / m-cresol / p-cresol molar ratio 10/54/36 and Mw 4000) 6.7 g (2) o- Naphthoquinonediazide compound (condensation product of pyrogallolacetone resin Mw3000 and o-naphthoquinonediazide-5-sulfonyl chloride: esterification rate 30%) 1.5 g (3) polyethylene glycol # 2000 0.2 g (4) FC-430 (Sumitomo 3M Co., Ltd. 0.03 g (5) cis-1,2-cyclohexanedicarboxylic acid 0.2 g (6) Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.08 g (7) 2,4-bis (Trichloromethyl) -6- (p-methoxystyryl) -s-triazine 0.15 g (8) 1,3,3-tri Chirunitoro - spiro (2'H-1'-benzopyran - 2,2'-indoline) and complexes of tin chloride 0.16 g (9) Methyl cellosolve 100 ml

Sample 2 (1) Novolac resin (phenol / m-cresol / p-cresol molar ratio 10/54/36 and Mw 4000) 6.7 g (2) o-naphthoquinonediazide compound (pyrogallolacetone resin Mw 300 0 and o-naphthoquinonediazide-5-sulfonyl chloride condensate: esterification rate 30%) 1.5 g (3) polyethylene glycol # 2000 0.2 g (4) FC-430 (Sumitomo 3M Co., Ltd.) 03g (5) cis-1,2-cyclohexanedicarboxylic acid 0.2g (6) Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.08g (7) 2,4-bis (trichloromethyl) -6- ( p-methoxystyryl) -s-triazine 0.15 g (8) 3-methyl-6-nitro-spiro (2H- - benzopyran) -2,2 '- (2'H-1'- beta naphthopyran) and the three complexes of antimony chloride 0.3 g (9) doped with Ce / Ni activated TiO ₂ 1.0 g (10 ) Methyl Cellosolve 100 ml

Comparative Sample 1 (1) Novolak resin (phenol / m-cresol / p-cresol molar ratio 10/54/36 and Mw 4000) 6.7 g (2) o-naphthoquinonediazide compound (pyrogallolacetone resin Condensate of Mw3000 and o-naphthoquinonediazide-5-sulfonyl chloride: Esterification rate 30%) 1.5 g (3) Polyethylene glycol # 2000 0.2 g (4) FC-430 (Sumitomo 3M Co., Ltd.) 0 0.03 g (5) cis-1,2-cyclohexanedicarboxylic acid 0.2 g (6) Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.08 g (7) 2,4-bis (trichloromethyl) -6- (P-Methoxystyryl) -s-triazine 0.15 g (8) Methyl cellosolve 100 ml

Comparative Sample 2 (1) Novolac resin (phenol / m-cresol / p-cresol molar ratio 10/54/36 and Mw 4000) 6.7 g (2) o-naphthoquinonediazide compound (pyrogallolacetone resin Condensate of Mw3000 and o-naphthoquinonediazide-5-sulfonyl chloride: Esterification rate 30%) 1.5 g (3) Polyethylene glycol # 2000 0.2 g (4) FC-430 (Sumitomo 3M Co., Ltd.) 0 0.03 g (5) cis-1,2-cyclohexanedicarboxylic acid 0.2 g (6) Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.08 g (7) 2,4-bis (trichloromethyl) -6- (P-Methoxystyryl) -s-triazine 0.15 g (8) Diacid Light Yellow 2G (yellow pigment) 0.05g (9) Methyl cellosolve 100ml

The resulting photosensitive lithographic printing plate had a density difference of 0.
15 grayscale and UGRA microdots 15
Use a metal halide lamp (Iwasaki Denki Idol Fin 2000) as a light source, with a 0L patch attached
It was exposed for 20 seconds from a distance of 90 cm. This exposed photosensitive lithographic printing plate was developed with a developing solution (SDR-1, Konica Corporation).
Positive developer, diluted 6 times, at a development temperature of 30 ° C,
Development was carried out for 12 seconds.

With respect to the exposed photosensitive lithographic printing plate, the exposure visibility (ΔOD) was evaluated by the following evaluation method. Further, the sensitivity and dot reproducibility of the photosensitive lithographic printing plate were evaluated by the following evaluation methods. The obtained results are shown in Table 1.

<Evaluation Method><Evaluation of Visibility of Exposure> Regarding the exposed photosensitive lithographic printing plate, the difference in optical density (ΔO between the exposed and unexposed photosensitive layers)
D) was measured using a Macbeth reflection densitometer.

<Evaluation of Sensitivity> The number of gray scale steps that completely clear the obtained gray scale phenomenon image was determined, and the sensitivity was evaluated by the number of steps. The larger the number of stages, the higher the sensitivity.

<Evaluation of Small Point Reproducibility> The phenomenon image of the obtained UGRA microdot 150L patch was evaluated according to the following evaluation criteria.

Evaluation Criteria A: Almost complete reproduction of 2% small dots B: Some thinning observed in part of 2% small dots C: Some slight thinning observed in whole of 2% small dots D: 2 % Fineness is clearly visible throughout the small dots

[0088]

[Table 1] Example 2 The support described in Example 1 was added to 50 g of water and 4 parts of methanol.
A coating solution in which the dyes shown in Table 2 were dissolved in an amount shown in Table 2 was applied to a mixed solvent consisting of 50 g and dried to form an undercoat layer. The coating amount of the dye in the undercoat layer and the difference in optical density (ΔD ₁ ) before and after the coating of the undercoat layer are as shown in Table 2.

Then, in Example 1, the photosensitive composition coating liquid used in the preparation of Comparative Sample 1 was applied using a wire bar and dried at 90 ° C. for 1 minute to prepare photosensitive planographic printing plate samples 3 to 5. And photosensitive lithographic printing plate comparison samples 3 to 4 were obtained.
At this time, the coating amount of the photosensitive composition was set to be 2.2 g / m ² as a dry weight.

With respect to the obtained photosensitive lithographic printing plate, the exposure visibility (ΔOD), sensitivity and dot reproducibility were evaluated in the same manner as in Example 1. The printing durability was evaluated by the following evaluation method. The obtained results are shown in Table 2.

<< Evaluation Method >><Evaluation of Printing Durability> As in Example 1, the lithographic printing plate obtained by exposure and development was applied to a printing machine (GTO manufactured by Heidel Co.), and coated paper and printing ink (Toyo Printing is performed using New Bright Red, manufactured by Ink Mfg. Co., Ltd., and fountain solution (SEU-3; 2.5%, manufactured by Konica Co., Ltd.), and defective inking or non-image appears in the solid part of the image part of the printed matter. Printing was continued until the ink was inked on the area, and the number of prints at that time was counted.

[0092]

[Table 2] Example 3 The support described in Example 1 was coated with the photosensitive composition coating liquid used in the preparation of Comparative Sample 1 in Example 1 using a wire bar and dried at 90 ° C. for 1 minute to expose the support. A layer was formed to obtain a photosensitive lithographic printing plate comparison sample 5. At this time,
The coating amount of the photosensitive composition is 2.2 g / m ² as a dry weight.
So that

On the photosensitive layer of the photosensitive lithographic printing plate comparison sample 5, polyvinyl phosphonic acid (1.5 g) and the amount shown in Table 3 in a mixed solvent of 20 g of water and 100 g of benzyl alcohol are shown in Table 3. After mixing the dyes and dispersing in a ball mill, spray coating using air spray,
After drying at 90 ° C. for 2 minutes to form an overcoat layer, photosensitive lithographic printing plate samples 6 and 7 and photosensitive lithographic printing plate comparative sample 6 were obtained.

The coating amount of the dye in the overcoat layer and the difference in optical density (ΔD ₂ ) before and after the application of the overcoat layer are as shown in Table 3.

With respect to the obtained photosensitive lithographic printing plate, the exposure visibility (ΔOD), sensitivity and dot reproducibility were evaluated in the same manner as in Example 1. The results obtained are shown in Table 3.

[0096]

[Table 3]

[0097]

According to the positive-working photosensitive lithographic printing plate of the present invention, excellent dot reproducibility and exposure visibility can be obtained without lowering the sensitivity.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shinichi Matsubara 1 Sakura-cho, Hino-shi, Tokyo Konica Co., Ltd. (72) Inventor Mitsuru Sasaki 1000 Kamoshida-cho, Midori-ku, Yokohama, Kanagawa Sanryo Kasei Co., Ltd. (72) Inventor Fumiyuki Matsuo 1000, Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Co., Ltd.

Claims (8)

[Claims] 1. A photosensitive composition comprising an o-quinonediazide compound and a photobleachable colored complex of spiropyran and a metal salt. 2. The photosensitive composition according to claim 1, wherein the photobleachable colored complex of spiropyran and a metal salt has a maximum light absorption wavelength at 340 to 450 nm. 3. The photosensitive composition according to claim 1 or 2, wherein the photosensitive composition contains an alkali-soluble resin. 4. A photosensitive lithographic printing plate comprising a support and a layer comprising the photosensitive composition according to any one of claims 1 to 3 provided on the support. 5. After providing an undercoat layer containing a photobleaching colored complex consisting of spiropyran and a metal salt on the support, o
-A photosensitive lithographic printing plate comprising a layer of a photosensitive composition containing a naphthoquinonediazide compound. 6. A layer of a photosensitive composition containing an o-quinonediazide compound is provided on a support, and then a layer containing a photobleachable colored complex of spiropyran and a metal salt is provided. Photosensitive lithographic printing plate. 7. The photosensitive lithographic printing plate according to claim 5, wherein an alkali-soluble resin is contained in the layer of the photosensitive composition containing an o-naphthoquinonediazide compound. 8. The photosensitive lithographic printing plate as claimed in claim 5, wherein the photobleachable colored complex comprising spiropyran and a metal salt has a maximum light absorption wavelength at 340 to 450 nm.