JPS61217047A - Retouch agent for lithographic printing plate - Google Patents

Abstract

PURPOSE:To obtain the retouch agent capable of rapidly removing only an unnecessary image by adding a ketonic acid or its ester and an acidic substance to the titled agent contg. o-quinone diazide type compd. or p-diazophenylamine type compd. CONSTITUTION:The retouch agent is prepared by comprising pyruvic acid, acetoacetic acid or its ketonic acid ester and an inorg. acid such as hydrochloric acid and the acidic substance such as p-tolulene sulfonic acid, and additionally a necessary thickener and a surface active agent, and if necessary, an org. solvent such as an ether and a lactone so as to be pH of 0.1-5. Only the parts necessary to correct, such as the unnecessary part produced in the image part, and the correct part, after the photosensitive lithographic printing plate contg. o-quinone diazide type compd. or p-diazophenylamine type compd. is exposed and developed, are removed without affecting any influence to another part except said parts to be corrected, thereby enabling a rapid correction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field 2) The present invention is directed to developing a photosensitive lithographic printing plate (hereinafter simply referred to as a PS plate) containing an 0-quinonediazide compound or a p-diazodiphenylamine compound. The present invention relates to a correcting agent for the resulting lithographic printing plate, and more particularly to a correcting agent used for erasing unnecessary image areas (areas that receive printing ink) of the lithographic printing plate.

(Prior Art) Lithographic printing plates For example, in lithographic printing plates such as those produced by photolithography, unnecessary images or image areas that need to be deleted or corrected may inevitably occur, making it necessary to correct them. - For example, dirt, scratches, cuts, etc. on the original film can cause overexposure and underexposure of the printing plate surface, resulting in unnecessary image areas that need to be corrected.

As correcting agents for removing unnecessary image areas of such lithographic printing plates, those containing glycol ethers and lactones are disclosed in Japanese Patent Publication No. 51-33442 and Japanese Patent Application Laid-Open No. 55-121.
It was shown in each publication No. 447. However, in recent years, there has been a high level of technical demand for correction agents, and not only high erasing speed but also an increase in correction work for minute areas. There has been an even stronger desire for something that has less negative impact on the image areas that should not be erased.Furthermore, a drawback of the conventional technology is a decrease in the insensitivity of the erased traces after burning. This is a heat treatment for strengthening the parts, and this is described in Japanese Patent Application Laid-Open Nos. 55-52061 and 57-
As described in detail in each publication of No. 133453, when conventional correcting agents are used to burn an image area after erasing the above-mentioned overexposed and underexposed areas (also referred to as halftones), the insensitivity of that area decreases. . For this reason, it becomes easier to receive the printing ink during the subsequent development ink application and printing, resulting in printing stains.(Objective of the Invention) Therefore, the object of the present invention is to To provide a lithographic printing plate corrector that has extremely little adverse effect and can erase only unnecessary image areas.

Another object of the present invention is to provide a lithographic printing plate corrector that does not reduce the insensitivity of erased marks regardless of whether or not burning is performed.

A further object of the present invention is to provide a lithographic printing plate corrector that has a high erasing speed in image areas and a high overall working efficiency.

(Structure of the Invention) In order to achieve the above object, the present inventors have made the present invention as a result of extensive research, and the gist thereof is to provide at least one member from the group of ketonic acids and ketonic acid esters. , and containing an acidic substance, 0-
This is a lithographic printing plate corrector obtained by developing a photosensitive lithographic printing plate containing a quinone diphosphate compound or a p-diazodiphenylamine compound.

The correcting agent of the present invention is excellent in that it has significantly improved adverse effects on close-up lines compared to conventionally known corrective agents, and does not reduce its anti-greasiness even when burned after erasing. Furthermore, from the above, it has been found that the present invention is a highly workable correcting agent with high erasing speed and no failure in plate making.

The present invention will be explained in more detail below.

Examples of the ketonic acid contained in the correcting agent of the present invention include α-ketonic acid, β-ketonic acid, and γ-ketonic acid. Examples of α-ketonic acids include pyruvic acid, benzoylformic acid, and phenylpyruvic acid; examples of β-ketonic acids include acetoacetic acid, propionyl acetic acid, and benzoylacetic acid; and examples of γ-ketonic acids include levulinic acid and β-penzoylpropionic acid. It will be done. As the ketonic acid ester, methyl of the above ketonic acid,
Examples include alkyl esters such as ethyl, propyl, isopropyl, butyl, isobutyl, amyl, and isoamyl, allyl esters such as phenol ester, allyl alkyl esters such as benzyl ester, and alicyclic esters such as menthyl ester.

Among the above-mentioned ketonic acids and ketonic acid esters to be contained in the modifier of the present invention, ketonic acid esters are preferred because they have high chemical stability. β-ketonic acid ester is more preferable because it has higher performance for the adjacent image line,
Most preferred is an ester of acetoacetic acid.

Although the purpose of the present invention can be achieved even if the amount of ketonic acid and ketonic acid ester contained in the modifier is low, in practice it is 2 to 95%, preferably 3 to 95%, based on the total weight of the modifier. Used at a concentration of 80%. In order to further improve the performance with respect to the above-mentioned adjacent drawing lines, the ratio should be 5 to 60%.
, most preferably at a concentration of 7 to 40%.

Examples of acidic substances include hydrochloric acid, sulfuric acid, persulfuric acid, phosphoric acid,
Inorganic acids such as nitric acid, permanganic acid, hydrofluoric acid, borofluoric acid, hydrosilicic acid, citric acid, malic acid, formic acid, acetic acid, lactic acid, oxalic acid, trichloroacetic acid, tannic acid, phytic acid, p-) Examples include organic acids such as luenesulfonic acid and phosphonic acid. Examples of the phosphonic acid include 1-hydroxyethylidene-1,1-diphosphonic acid, 1,2-diphosphonic acid, 1,2-dicarboxyethane, 1,2,2,3-tetraphospho/propane, and 2(2'-phosphonic acid). Mention may be made of noethylnoviridine, aminotri(methylenephosphonic acid), vinylphosphonic acid, polyvinylphosphonic acid, 2-phosphonoethane-1-sulfonic acid, water bathable copolymers of vinylphosphonic acid with acrylic acid and/or vinyl acetate. Among these acidic substances, phosphoric acid, hydrofluoric acid, borofluoric acid, hydrosilicic acid, acetic acid, trichloroacetic acid, and phosphonic acid are preferable for improving the correction effect, and phosphoric acid and borofluoric acid are more preferable. , hydrofluoric acid, and acetic acid.The modifying agent of the present invention exhibits sufficient performance in the acidic range.Preferably, the pH is 0.1 to 5, more preferably 0.15 to 3. Most preferably 0.2-2.
The range is 5. These acidic substances can be used alone or in combination of two or more, and are 0.1 to 20% by weight, preferably 0.3 to 10% by weight based on the total weight of the modifier.
% by weight, particularly preferably from 0.5 to 6. It is contained within the range of oak%.

The essential function of a correction agent is to remove unnecessary image areas on printing plates, but in addition to this essential function, it is important to consider how to improve incidental performance such as blurring at the boundaries of erased areas and compatibility with washing water. It is also a technique for preparing a correction agent. Therefore, it is preferable to further selectively add other organic solvent-based compounds, thickeners, surfactants, water, coloring pigments, etc. to the modifier of the present invention.

These will be explained in detail below.

Examples of other organic solvent compounds include ethers, ketones, lactones, alcohols, fatty acids, and other hydrocarbon solvents.

Typical examples of ethers include glycol ethers, such as methyl ethylene glycol,
Ethylene glycol monoalkyl ethers such as ethyl, isopropyl and butyl ether, ethylene glycol dialkyl ethers, such as diethylene glycol monoalkyl ethers and diethylene glycol dialkyl ethers such as methyl, ethyl, impropyl and isobutyl ether of diethylene glycol, For example, methyl and ethyl of ethylene glycol
, triethylene glycol monoalkyl ethers such as butyl ether, triethylene glycol dialkyl ethers such as ethylene glycol monophenyl (
T? ,:&! ) IJ Le) ether, propylene glycol monophenyl (Mata is tolylnoether, diethylene glycol monophenyl (or tolylnoether, dipropylene glycol monophenyl (Mata is tolylnoether, triethylene glycol monophenyl)
or tolylnoether, tripropylene glycol monophenyl (or tolylnoether, trimethylene glycol monophenyl (t?, =, Furmonophenyl (or alkylene glycol aryl (or alkyl aryl) such as tolyl ether, e.g. ethylene glycol monoalkyl such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, etc.)
There are k7 acetates. Examples of ketones include acetone, methyl ethyl ketone, methyl propyl ketone,
Methyl isopropyl ketone, methyl butyl ketone, methyl methyl ketone, methyl hexyl ketone, diethyl ketone, ethyl butyl ketone, butylone, diisopropyl ketone, parerone, mesityl oxide, acetylacetone, acetonylacetone, cyclohexanone, methylcyclohexanone, acetophenone, etc. Ru. Examples of lactones include butyrolactone, valerolactone, and hexanolactone.

Alcohols include aromatic alcohols and alicyclic alcohols! ! *Also includes aliphatic alcohols and polyhydric alcohols. Aromatic alcohols include, for example, benzyl alcohol, tolyl carbinol, vanillyl alcohol, 7
Talyl alcohol, α-Oyohy β-phenylethyl alcohol, α, β-dioxyethylbenzene, 1-phenyl-1-propatol, 2-phenyl-2-propatol, 2-phenyl-1-propatol, 3-phenyl Those with saturated aromatic hydrocarbon side chains, such as 7-enylbutanols such as propatool, 4-phenyl-1-butanol, and 4-phenyl-2-butanol, and 1-phenyl-2- Aromatic hydrocarbons whose side chains have unsaturated bonds, such as propyn-1-ol and cinnamyl alcohol, and aromatic hydrocarbons containing halogen atoms such as fluorine, bromine, chlorine, and iodine, G! There is something that has been replaced. Alicyclic alcohols include, for example, cyclohexanol,
There are sterins like cyclopentanol and lanolin, which are terpene alcohols. Fatty i-valent fluorols include methyl alcohol, ethyl alcohol, propatool, butanol, pentanol, hexanol, heptatool, octatool, nonanol, decanol,
Saturated aliphatic alcohols such as undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, octadecanol,
In particular, there are unsaturated aliphatic-hydric alcohols such as allyl alcohol, oleyl alcohol, elaidyl alcohol, lilyl alcohol, crunyl alcohol, geraniol, and propargyl alcohol. For polyhydric alcohols,
Examples include dihydric alcohols such as ethylene glycol, propanediol, trihydric alcohols such as glycerin, and polyglycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and diglycerin. .

Examples of fatty acids include propionic acid, butyric acid, valeric acid,
caproic acid, enanthic acid, caprylic acid, pelargonic acid,
These include saturated fatty acids such as capric acid, undecylic acid, and lauric acid, and unsaturated fatty acids such as acrylic acid, crotonic acid, undecylic acid, oleic acid, linoleic acid, ricinoleic acid, and linuric acid.

Other hydrocarbon solvents, for example, have a boiling point of 12
Petroleum fractions around 0 to 250°C, toluene, xylene, benzene, turpentine, kerosene, and lactams such as N-methylpyrrolidone.

Various examples include N-dimethylformamide, dimethylsulfoxide, tetrahydrofuran, dioxane, and acetic anhydride.

Among the other organic compounds listed above, preferred are glycol ethers, ketones, lactones, aromatic alcohols, and other hydrocarbon solvents, which have a high property of dissolving or swelling the image area. . More preferably, ethylene glycol monoalkyl ethers, diethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, methyl ethyl ketone,
Methylpropyl ketone, diisopropyl ketone, acetylacetone, acetonylacetone, cyclohexanone,
Methylcyclohexanone, lactones, benzyl alcohol, α- and β-7 enyl ethyl alcohol, xylene, N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, dioxane, most preferably diethylene glycol dimethyl ether, diethylene glycol These are monomethyl ether, methyl ethyl ketone, diisopropyl ketone, cyclohexanone, xylene, N,N-dimethylformamide, dimethyl sulfoxide, and dioxane. The organic compounds mentioned above that can be selectively added can be used alone or in combination of two or more.
The content is 85% by weight, preferably 10 to 70% by weight. As an example of a preferable preparation technique for improving the incidental performance, based on the total weight of the modifier, 5 to 60 [t%] of glycol ethers, 3 to 1% of at least one of ketones and lactones, and 1% of other carbonized The composition ranges from 5 to 40% by weight of hydrogen-based solvent. More preferably, glycol ethers are 8 to 50% by weight, ketones are 5 to 30% by weight, and other hydrocarbon solvents are 7 to 25% by weight.
The composition range is 1% by weight.

Examples of thickeners include inorganic thickeners such as silicic acid fine powder, methyl cellulose, hydroxypropyl methyl cellulose, modified cellulose of carboxymethyl cellulose 1 (ale), gum arabic, polyvinylpyrrolidone,
polyvinyl methyl ether, polyethylene glyfur,
Examples include polymeric compounds such as polypropylene glycol, vinyl methyl ether-maleic anhydride copolymer, and vinyl acetate-maleic anhydride copolymer. Among these, modified cellulose, polyvinylpyrrolidone, and the above-mentioned two types of maleic anhydride copolymers are preferred, and modified cellulose such as hydroxypropyl methylcellulose and polyvinylpyrrolidone are most preferred. These thickeners can be used alone or in a mixture of two or more, and the amount added can be changed to achieve the desired viscosity, but preferably 0.5 to 25% by weight based on the modifier of the present invention. %, more preferably 1
It is used in a range of 15% by weight.

As surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyrylphenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, Pentaerythritol fatty acid partial esters, phlopylene gelicol monofatty acid esters, sucrose fatty acid external esters, oxyethylene oxypropylene block copolymers, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol Fatty acid esters, polyglycerin fatty acid partial esters, polyoxyethylenized castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid jetanol esters I, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkyl Nonionic surfactants such as amines, triethanolamine fatty acid esters, trialkylamine oxides, fatty acid salts, bichenates, hydroxyalkanesulfonates, alkanesulfonates, dialkylsulfosuccinic acid ester salts, linear alkylbenzenes Sulfonate salts, branched alkylbenzene sulfone ams, alkylnaphthalene sulfonate salts, alkylphenoxypolyoxyethylene propyl sulfonate salts, polyoxyethylene furkylsulfophenyl ether [m, N-methyl-N-oleyl taurine sodium N-alkyl sulfosuccinic acid monosodium salts, petroleum sulfonates, sulfated castor oil, sulfated beef leg oil, sulfate ester salts of fatty acid alkyl esters, alkyl sulfate ester salts,
Polyoxyethylene alkyl ether sulfate ester salts, fatty acid monoglyceride sulfate ester salts, polyoxyethylene alkyl phenyl ether sulfate ester salts,
Polyoxyethylene styrylphenyl ether sulfate ester salts, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphate ester salts, polyoxyethylene alkyl phenyl ether phosphate ester salts, partially saponified products of styrene-maleic anhydride copolymer , partially saponified olefin-maleic anhydride copolymers, anionic surfactants such as naphthalene sulfonate formalin condensates, alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, polyethylene polyamines Examples include cationic surfactants such as derivatives, amphoteric surfactants such as carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfate esters, and imidacillins. Among the surfactants listed above, the term "polyoxyethylene" can also be read as "polyoxyalkylene" such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. Among these, nonionic surfactants and anionic surfactants are preferred, and surfactants with an HLB of 9 or more are more preferred because each component contained in the modifier mixes well. Furthermore, polyoxyethylene alkyl phenyl ethers, oxyethylene oxypropylene block copolymers, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, and polyglycerin fatty acid partial esters are modifiers. This is preferable in order to improve the image area erasing effect. Most preferred is oxyethylene oxypropylene block copolymer. These surfactants may be used alone or in a mixture of two or more, and may be used in an amount of 0.5 to 30% by weight, preferably 3 to 2% by weight based on the total weight of the modifier of the present invention.
It is contained in a range of 0% by weight.

Water is contained in various components such as acids and is necessarily added, but it can also be added selectively.
The modifier of the present invention has a subtle effect on its performance.

For this reason, the preferable amount to be added is 1 to 1 to
30% by weight, more preferably 3-20%.

Coloring pigments can be included when visual contrast is desired, and specifically include dyes such as crystal violet, 7-lanine, brilliant blue, malachite green, and citrodamine B, as well as inorganic pigments and organic pigments. etc. These colorants are present in an amount of 0.0001 to 0.05% by weight based on the total weight of the correction agent according to the present invention.
, preferably in the range of 0.0C)1 to O.01ffiffi%.

The modifier of the present invention is an 0-quinone diphosphate compound or a p-
- It is applied to a lithographic printing plate obtained by developing a PS plate containing a diazodiphenylamine compound, and is particularly used for correcting and erasing image areas. These PS versions will be explained in detail below.

Supports for PS plates are dimensionally stable plate-like materials, including those conventionally used as supports for printing plates. Examples of such supports include paper, plastics (for example, paper laminated with polyethylene, polypropylene, polystyrene, etc.), luminium plates (including luminium alloys), zinc plates, copper plates, iron plates, composite metal plates ( Metal plates such as iron plates coated with chromium, such as cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene,
Plastic films such as polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc., paper or plastic films laminated or vapor-deposited with the above metals, Japanese Patent Publication No. 48-1832
This includes a sheeting sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in Japanese Patent No. '7.

The 28 plate support used in the present invention has a hydrophilic surface. Here, the term "hydrophilic surface" refers to a surface that becomes wet with dampening water and repels printing ink when the lithographic printing plate is mounted on a printing press and printed under standard conditions.

The surface of the support is preferably subjected to hydrophilic treatment.

There are various methods for hydrophilic treatment. For example, in the case of a support with a plastic surface, methods such as chemical treatment, electric discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, activated plasma treatment, laser treatment, etc. and undercoating after these treatments are used. There is a method of applying layers. In addition, in the case of a support having a metal surface such as aluminum, graining treatment such as brush polishing and electrolytic polishing, immersion treatment in an aqueous solution of sodium silicate, fluoridated zirconate, phosphate, etc. There are plating, coating, anodizing treatments, etc.

Among the above-mentioned supports, a plate having a grained or anodized aluminum surface, or a chromium-coated iron plate is preferable because it improves the adhesion of the photosensitive layer.

Anodizing baths include hydrochloric acid, nitric acid, chromic acid, boric acid,
Examples include aqueous solutions of various acids such as sulfuric acid, persulfuric acid, phosphoric acid, sulfamic acid, and oxalic acid. An aluminum plate that has been grained and further anodized is more preferred. An aluminum plate that has been brush-polished and further anodized, or an aluminum plate that has been brush-polished and electrolytically polished and further anodized has particularly favorable adhesion with the photosensitive layer, so that the resulting ps The printing plate has high printing durability, and the correction agent of the present invention is particularly advantageous. Furthermore, surface roughness is known as one method of expressing the hydrophilicity of a support, and it has been found that this surface roughness also serves as a measure of the adhesiveness of the photosensitive layer. Therefore, the center line average roughness Ra [μm] should be 0.40 or more, and even 0.50.
A value of 0.80 or less is preferable. It shows the most preferable adhesiveness, and the preferable range is 0.60 or more and 0.80 or less. (Measuring instrument: Beltmeter, Tracer RHT 3150e, manufactured by Pelten AG, West Germany) FS plates having a photosensitive composition containing an 0-quinonediazide compound are widely known to act in a positive tone, and are preferred. - Naphthoquinone diphosphate compounds. Among the 0-naphthoquinone di)' compounds, in particular, 0-naphthoquinone diazide sulfonic acid esters or 0-naphthoquinone diazide carboxylic acid esters of various hydroxy compounds, and 0-naphthoquinone diazide sulfone of aromatic amino compounds. Acidamide or 0-su7toquinone dioxycarboxylic acidamide is preferred.

Preferred hydroxy compounds include condensation resins of phenols and carbonyl group-containing compounds. Examples of the phenols include phenol, cresol, resorcinol, and pyrogallol, and examples of the carbonyl and group-containing compounds include formaldehyde, benzaldehyde, and acetone. Preferred hydroxyl compounds include phenol formaldehyde resin,
Examples include cresol/formaldehyde resin, pyrogallol resin, and resorcinol/benzaldehyde resin.

Typical specific examples of 0-quinonediazide compounds include:
Esters of benzoquinone-(1,2-diazide sulfonic acid or naphthoquinone-(1,2,)-diazide sulfonic acid and 7-enol formaldehyde resin or cresol-formaldehyde resin, JP-A-1982-: LO44)
The ester of naphthoquinone-(1,2-diazide-(2)-5-sulfonic acid and resorcinol-benzaldehyde resin described in U.S. Pat. No. 3,635,
Ester of naphthoquinone-(1°2)-dioxytosulfonic acid and pyrogallol acetone resin described in No. 709, naphthoquinone-(1,2) described in JP-A-55-76346. -Jiroshito-(2
) - Ester combinations of 5-sulfonic acid and resorcinol-pyrogallol-acetone copolymerized metals are listed. Other useful. - As a quinonediazide compound, JP-A-1987-
To the polyester having a hydroxyl group at the end described in Japanese Patent No. 117503. - An esterification reaction of naphthoquinonediazide sulfonyl chloride, which can be combined with a homopolymer of p-hydroxystyrene or a copolymerizable monomer of Ike as described in JP-A-50-113305. 〇-Naphthoquinonediazide sulfonyl chloride subjected to esterification reaction, ester of bisphenol formaldehyde resin and 0-quinonediazide sulfonic acid described in Japanese Patent Publication No. 54-29922, U.S. Patent No. 3,859,0
Alkyl acrylates described in No. 99 specification,
Condensate of copolymer of chloroyloxyalkyl carbonate and hydroxyalkyl acrylate with 0-quinonediazide sulfonyl chloride, Japanese Patent Publication No. 1986-17
481, a reaction product of a copolymerization product of styrene and a phenol derivative with O-quinonediazide sulfonic acid, p- as described in U.S. Pat. No. 3,759,711, Amides of copolymers of minostyrene and other copolymerizable monomers and 0-naphthoquinonediazide sulfonic acid or 0-naphthoquinonediazidecarboxylic acid, and also polyhydroxybenzophenone and 0-naphthoquinonediazide sulfonyl chloride. Examples include esterified products of.

Although these 0-7toquinone diazide compounds can be used alone, it is preferable to mix them with an alkali-soluble resin and provide this mixture as a photosensitive layer. Suitable alkali-soluble resins include novolak-type phenolic resins, specifically phenol formaldehyde resins,
Cresol formaldehyde resin, JP-A-55-571
It includes phenol/cresol formaldehyde copolycondensate a-fat as described in Japanese Patent No. 341.

Furthermore, as described in Japanese Patent Publication No. 50-125806, in addition to the above-mentioned phenol oil resistance, phenol substituted with an alkyl group having 3 to 8 carbon atoms, such as t-butylphenol formaldehyde resin, or When used together with a condensate of cresol and formaldehyde,
Even more preferred. The content of the 0-quinonediazide compound is preferably 5 to 80% by weight, and preferably 10 to 50% by weight, based on the total solid content of the photosensitive composition.

The content of the alkali-soluble resin is preferably 30 to 90% by weight, particularly preferably 5% by weight based on the total solid content of the photosensitive composition.
It is 0 to 85% by weight.

A photosensitive composition containing a p-diazodiphenylamine compound is widely known as a negative PS plate. The negative PS plate contains a photosensitive p-diazodiphenylamine compound and preferably a polymer compound, and conventionally known photosensitive p-diazodiphenylamine compounds can be used, and preferred ones are used. Salts of p-diazodiphenylamine resins soluble in organic solvents, such as salts of halo-diazodiphenylamine and condensates of formaldehyde or acetaldehyde or benzaldehyde and hexafluorophosphates, salts of toluenesulfonates, etc.
Examples include salts with -hydroxy-4-methoxybenzophenone-5-sulfonate. Examples of polymer compounds include acrylic acid or methacrylic acid copolymers, crotonic acid copolymers, itaconic acid copolymers, maleic acid copolymers, cellulose derivatives having carboxyl groups in their side chains, and cellulose derivatives having carboxyl groups in their side chains. Polyvinyl alcohol 7784, a hydroxyalkyl acrylate or methacrylate copolymer having a carboxyl group in its side chain, an unsaturated polyester resin having a carboxyl group, etc. are preferably used. More preferably, it is a polymer compound having an acid value of 10 to 300. Moreover, more preferably, JP-A-50
-The following general formula CI described in Publication No. 118802
) and a polymer containing a structural unit represented by the following general formula (ID), a monomer unit having an aromatic hydroxyl group as described in JP-A-57-192951, and general A polymer containing a structural unit represented by the formula ([) is used.

R' R3 (-OH,-Of +(1!H,-
0scoo+aa, cuasnH (!N Yosei CI)
(II) (In the general formula, R1 represents a hydrogen atom or a methyl group, R1 is a hydrogen atom, a methyl group,
(represents an ethyl group or a chloromethyl group, Rs represents a hydrogen atom or a methyl group, and n represents a numerical value of 1 to 1o) The content of the p-diazodiphenylamine compound in the photosensitive composition according to the present invention is 1 ~70% by weight, preferably 3
~60% by weight.

The photosensitive composition as described above can be provided separately into multiple layers, and additives such as dyes, plasticizers, and components imparting printout performance can be added as necessary.

The coating amount of the photosensitive composition provided on the support is 0.1
~7 g/nl is preferable, more preferably 0.5~
It is 4fi/i.

The PS plate thus obtained is exposed through a transparent original to a light source rich in active light, such as a carbon lamp, mercury lamp, metal halide lamp, tungsten lamp, or xenon lamp, and then developed.

The developer used preferably contains at least one of an alkaline agent and an organic solvent, and is selected depending on the type of photosensitive layer. This fact was published in Japanese Unexamined Patent Application Publication No. 59-58
It is described in detail in Japanese Patent No. 431.

For the development of PS plates containing p-diazodiphenylamine compounds, ethylene glycol monophenyl ether, benzyl alcohol t-containing [L].

Generally, the developing solution for PS plates containing an 0-quinonediazide compound has a molar ratio of [Sin
, ] / [M] = 0. 5 ~1.
5 (L 5ins ], [M is the molar concentration of S10. and K + Na + 11, respectively.
etc.) indicates the molar concentration of total alkali metals, and 5
Those containing 0.8 to 8% by weight of 101 are common.

Methods for developing a PS plate illuminated with the above-mentioned developer include a method of jetting the developer from multiple nozzles, a method of immersing the plate in the developer, and a method of wiping with a sponge moistened with the developer. Various conventionally known methods are possible.

As mentioned above, if there is an unnecessary image area on the lithographic printing plate obtained by subjecting the PS plate to rlfJ image exposure and development,
The image area is erased by applying the correction agent of the present invention onto the image area.

When the correcting agent of the present invention is applied to the image area of a lithographic printing plate, it is preferable to wash the plate with water after development and use a squeegee to remove the washing water before erasing the plate. A specific method for erasing is to apply the correction agent to the image area and leave it for about 10 seconds to several minutes, or after applying it, rub it lightly with a cotton pad, and then rinse with water to remove the eraser. The most common method is to leave.

The lithographic printing plate from which unnecessary image areas have been erased in this way is processed after the usual processing steps such as development inking and/or gumming, or after finishing the development inking and/or gumming treatment after burning. , for printing. The correcting agent of the present invention is advantageously used because it does not cause deterioration in insensitivity due to burning of erased marks.

The correcting agent of the present invention can quickly erase unnecessary image areas and has extremely little adverse effect on adjacent images, improving the efficiency of plate-making work.

Furthermore, since the correcting agent of the present invention does not reduce its insensitivity even after burning the erased marks, failures caused by plate making and troubles during printing can be eliminated, and the efficiency of plate making and printing is improved.

The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto. In the following examples, "parts" represent parts by weight, and "%" means % by weight.

Example 1 An aluminum plate with a thickness of 0.3 μ was electrochemically roughened in a nitric acid solution, thoroughly washed, and then anodized in a sulfuric acid solution to form an oxide film of 2.59 mm on the surface of the aluminum plate. formed on top.

After washing with water and drying, a resorcin benzaldehyde resistance layer synthesized according to the example of JP-A No. 56-4044 was applied.
3 parts of esterified product of toquinone with 1,2-diazido-5-sulfonyl chloride, 9 parts of cresol-formalin novolac layer and Victoria Pure Blue BOH
(manufactured by Hodogaya Chemical Industry Co., Ltd.) A photosensitive solution containing 100 parts of 2-methoxyethanol and 0,12[O] was applied onto the above support using a rotary coater and dried to form a photosensitive layer of 2-89/m. A positive PS plate was obtained.

A halftone photographic transparent positive was placed on top of this, and from a distance of 0.8 m, the metal halide lamp used in Example 1 was used to
It was exposed to light for seconds and developed with the following developer to obtain a printing plate.

(Developer Potassium Nosilicate A (Sin, 26%, K, 013.5%) 120 parts 8
6% potassium hydroxide 15.5 parts water
5
00 copies Next, when unnecessary image areas were erased using the following correcting agent of the present invention, they were completely erased in 40 seconds.

When this printing plate was printed after being burned at 250° C. for 8 minutes, the erased marks were not stained at all.

Also, no adverse effects such as staining appeared on the halftone dots that were 0.2 areas close to the erased area.

(Modifier of the present invention) Xylene 5 parts Cyclohexanone 20 parts Diethylene glycol dimethyl ether 20 parts Pyruvic acid 20 parts Hydroxypropyl methylcellulose 1.8 il (28-30% methoxy groups, 7-12% hydroxypropoxy groups, 2% aqueous solution at 20°C) The viscosity of is 4.8~?, 2
cps stuff. Nopruronic P-85 (manufactured by Asahi Tunka ■, oxyethylene oxypropylene block cobolimano 1z part 85% phosphoric acid 2.1 parts 95%
Acetic acid 2 parts Silicic acid fine powder
6.5 parts water
10 parts 25°Cp
H0,33 Example 2 When the unnecessary image area of the printing plate obtained in the same manner as in Example 1 was erased with the following correcting agent of the present invention, it was completely erased in 30 seconds. This printing plate was burnt in the same manner as in Example 1, and development ink was applied (Sakushi 28 version development ink 5pa-1, manufactured by Konishiroku Photo Industry Co., Ltd.). There was no staining at all, and the halftone dots close to the erased area did not stain up to about 0.2''.

(Modifier of the present invention) The modifier of Example 1 except that 20 parts of diethylene glycol dimethyl ether was changed to 15 parts, and 20 parts of pyruvic acid was replaced with 25 parts of ethyl acetoacetate (25°C, pH 1,75
) Comparative Example 1 A correcting agent having the following composition similar to that described in JP-A-55-121447 (Example 4) was prepared, and the image area of the obtained printing plate was erased in the same manner as in Example 1. Burning and inking were performed in the same manner as in Example 2.

It was found that the development ink adhered to the halftone erased traces of the obtained printing plate, resulting in a decrease in oil insensitivity. Also, the halftone dots near the erased area are 1. It was found that the developing ink was smeared with the developing ink even in areas far away, which had a large negative effect on the adjacent image.

(Known modifier) δ-valerolactone 29.5 parts Ethylene glycol dimethyl ether 30 parts Solvent naphtha (boiling point 140-200°C) 10 parts Hydroxypropyl methylcellulose 1.5 parts (Nopluronic P-85 same as Example 1) ) 10 parts 85% phosphoric acid 5 parts water

10 parts Silicic acid fine powder 5 parts Example 3 An aluminum plate with a thickness of 0.31 m was electrochemically roughened in a hydrochloric acid solution, thoroughly washed, anodized in a sulfuric acid solution, and sealed with hot water. An oxide film of 2.7 fl/7ri'' was formed on the surface.

After washing with water and drying, 5 parts of an esterified product of m-cresol formaldehyde resin and naphthoquinone-1,2-diazide-8-sulfonyl chloride and cresol formalin novolak tree I (7 el/-l: cresol = 2 = 8)
10 parts and Victoria View Blue BOH0,1
A photosensitive solution prepared by dissolving 4 parts of 2-methoxyethanol in 100 parts of 2-methoxyethanol was applied to the support and dried to obtain a positive PS plate having a photosensitive layer of 2.8 E/G.

A halftone photographic transparency was placed on top of this, exposed and developed in the same manner as in Example 1 to obtain a printing plate. When unnecessary image areas of this printing plate were erased with the following correction agent of the present invention, 3
It was completely erased in 0 seconds.

When this printing plate was printed after being burned at 260° C. for 7 minutes, there was no printing stain on the erased traces, including the intermediate tones. Further, the halftone dots close to the erased area had no adverse effects such as printing stains up to approximately 0.2 shearing.

(Modifier of the present invention Noxylene 4 parts Cyclohexanone 155 parts Ethyl acetate 30 parts Diethylene glycol monomethyl ether 20 parts Silicic acid fine powder 7 parts Hydroxypropyl methylcellulose 1 part Pluronic P-
859 parts 85% phosphoric acid 2.1 parts water

11 parts (25°C pH 2, 1 O) Example 4 When the unnecessary image area of the printing plate obtained in the same manner as in Example 3 was erased with the following correction agent of the present invention, it was completely erased in 15 seconds. When this printing plate was burned in the same manner as in Example 3 and printed using a printing press, the erased traces, including the halftones, did not cause printing stains. There were no adverse effects such as printing stains up to around 0.2 +o+.

(Modifier of the present invention) Xylene 5 parts diethylene glycol dimethyl ether 15 parts N,N-dimethylformamide 9 parts dioxane
4-part cyclohexanone
20 parts levulinic acid 1
0 parts Hydroxypropyl methyl cellulose 1.8 parts Silicic acid fine powder 6 parts Pluronic P-8513 parts 99.5% Acetic acid 2 parts 85%
Phosphoric acid 2.6 parts 42% borofluoric acid 1.5 parts Water
10 parts Pigment (Food Red No. 1) 0.002 parts (2
5°C pH 0.85) A similar elimination experiment was conducted using the exemplified compounds ethyl pyruvate, ethyl benzoylacetate, β-benzoylpropionic acid, and ethyl levulinate in place of levulinic acid in the corrector used in Example 4. , the effects of the present invention were obtained.

Example 5 When the unnecessary image area of the printing plate obtained in the same manner as in Example 3 was erased using the following correcting agent of the present invention, it was completely erased in 15 seconds. When this printing plate was burned in the same manner as in Example 3 and printed using a printing press, the erased marks, including the halftones, did not cause printing stains. Further, the halftone dot area 0.3.31 m1 close to the disappearing area had no adverse effects such as printing stains.

(Modifier of the present invention xylene 5 parts diethylene glycol dimethyl ether 15 parts N,N-dimethylformamide 10 parts cyclohexanone
20 parts methyl acetoacetate
12 parts hydroxypropyl methylcellulose 1.
8 parts Silicic acid fine powder 6.5 parts Pluronic P-8513 parts 99.5% Acetic acid 2 parts 85%
Phosphoric acid 266 parts 42% Borohydrofluoric acid 1.5 parts Water
10 parts dye (
Food Red No. 1) 0.002 parts (25℃
(pH 1,95) Comparative Example 2 When unnecessary image areas of the printing plate obtained in the same manner as in Example 3 were erased with the following known correcting agent, the erased area was 60%
Not only did it take several seconds, but when this printing plate was burned in the same manner as in Example 3 and printed on a printing press, printing ink adhered to the erased ψ halftone area, and the printed matter was smeared.

From this, it can be seen that the correcting agent causes a decrease in the insensitivity when the erased traces are burned. It was also found that printing stains occurred in the halftone dot portions that were 0.7 times closer to the erased portions, which had a significant adverse effect on adjacent print lines.

(Known corrective agent) Xylene 5iN, N
-Dimethylformamide 15 parts Cyclohexanone 30 parts Diethylene glycol monomethyl ether 15 parts Hydroxypropyl methylcellulose 1.89 Silicic acid fine powder 6.5 parts Pluronic P-8512 parts 99.5% Acetic acid 2 parts 85% Phosphoric acid 2.6 parts Water
10 parts Pigment (Food Red No. 1) 0.002 parts Example 6 An aluminum plate with a thickness of 0.24 m was immersed in a 20% aqueous sodium phosphate solution to degrease it, and then soaked in 0.2N hydrochloric acid at 3 A/@ After electropolishing at a current density of , it was anodized in a sulfuric acid bath. At this time, the amount of anodic oxidation was 3.0 I/
It was rd. The grains were sealed with a sodium metasilicate water bath solution to obtain a support for a lithographic printing plate. A photosensitive liquid having the following composition was applied to this aluminum plate. Then 9
Dry for 2 minutes at a temperature of 0°C to obtain a film thickness of 18rn9/dTI?
As a result, a negative-type PS version that can be easily erased was obtained.

(Photosensitive liquid) Copolymer 5.0 parts Diryozo resin 0.5 parts Victoria Pure Blue EOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.1 parts Methyl cellosolve 100 parts However,
The above copolymer has a weight ratio of p-hydroxyphenylmethacrylamide/acrylonitrile/ethyl acrylate/
It has a composition (molar ratio) of methacrylic acid = 8/24159.5/8.5, and has an average molecular weight CM? ) = 5.8
The diazo resin is a hexafluorophosphate of a condensate of p-diazodiphenylamine and paraformaldehyde.

A halftone photographic transparent negative was placed on top of this, and the length was 0.8 m using the metal halide lamp and Idol Fin 2000.
Exposure was carried out for 50 seconds from a distance of , and development was performed using the following developer to obtain a printing plate.

(Developer solution Nopendyl alcohol 5.0 parts Sodium carbonate 0.5 parts Sodium sulfite 0.5 parts 3-Methyl-3-
Methoxybutanol 26.5g (S water
After 100 copies, unnecessary image areas were erased with the following correction agent of the present invention and the original ink was applied, and it was possible to erase in 20 seconds.
No image residue was observed in the intermediate tones. Furthermore, no adverse effect on the adjacent image line occurred up to the vicinity of 0°1111 m.

(Modifier of the present invention Ethyl facetoacetate 20 parts Cyclohexanone 30 parts Diethylene glycol monomethyl ether 16 parts Xylene 5 parts Hydroxypropyl methyl cellulose 8 parts Pluronic P-
858 parts 55% hydrofluoric acid 0.9 parts 60%
1-hydroxyethylidene-1,1-diphosphonic acid
2.2 parts water
Comparative Example 3 The composition of the corrective agent used in Example 6 was the same as that of the acidic substance (55% hydrofluoric acid, 60% 1-hydroxyethylidene). -1,1-diphosphonic acid) was prepared and the unnecessary image area of the printing plate obtained in the same manner as in Example 6 was erased.
I could not erase it even after several minutes had passed.

Comparative Example 4 The following correction agent having a composition similar to that described in Japanese Patent Publication No. 46-16047' (Example 6) was prepared, and the image area of the obtained printing plate was erased in the same manner as in Example 6. Even after a period of time, it could not be erased.

(Known correction agent)

Claims (1)

[Claims] A lithographic printing plate obtained by developing a photosensitive lithographic printing plate containing an o-quinonediazide-based compound or a p-diazodiphenylamine-based compound, which is characterized by containing a ketonic acid and/or a ketonic acid ester, and an acidic substance. correction agent.