JP2687047B2 - Lithographic printing plate manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a lithographic printing plate from a photosensitive lithographic printing plate, and in particular, a negative photosensitive lithographic printing plate is developed with an alkali metal silicate aqueous solution containing no organic solvent. It relates to a method for producing a lithographic printing plate.

[0002]

2. Description of the Related Art Photosensitive lithographic printing plates include negative-type and positive-type photosensitive lithographic printing plates. When developing each printing plate, it is common to use a dedicated developer. Target. Therefore, when these two types of photosensitive lithographic printing plates are used simultaneously, two types of developing solutions are required. Further, in the case of developing a large number of two types of photosensitive lithographic printing plates, two automatic processors and the like are required, and there is a problem in terms of cost such as installation cost and installation area, and economy.

When the two types of photosensitive lithographic printing plates are commonly processed by one automatic developing machine, a developing solution is used each time depending on the type of the photosensitive lithographic printing plate to be processed. Since it has to be replaced, it is extremely wasteful in terms of work efficiency and economy.

In order to solve such a problem, a method of developing two kinds of photosensitive lithographic printing plates with the same developing solution has been conventionally proposed, but in the actual situation, good results have not been obtained yet. is there. The following can be considered as a reason for this. That is, generally, a developer for a positive lithographic printing plate having a photosensitive layer composed of an o-quinonediazide compound and an alkali-soluble resin has a pH of 1 mainly containing silicate.
When the unexposed area of a negative lithographic printing plate consisting of a water-insoluble diazo resin and an alkali-soluble resin is developed with this developer, it cannot be developed at all However, there is a problem that stains are likely to occur during printing.
On the contrary, when developing the exposed part of the positive type lithographic printing plate with the negative type lithographic printing plate developing solution, similarly, the development cannot be performed well, the residual film remains, and it causes stains on printing, or In the negative developing solution of No. 1, the photosensitive layer of the positive type lithographic printing plate is easily dipped by the solvent contained in the negative developing solution, so that the development acceptability is narrowed and the oil sensitivity and the printing durability are deteriorated. Was a problem.

For the purpose of solving the above-mentioned problems, Japanese Patent Laid-Open No.
JP-A-56442 discloses a method of developing a negative photosensitive lithographic printing plate having a photosensitive layer composed of an alkali-soluble polymer, a monomer and a photopolymerization initiator, with a developer for a positive photosensitive lithographic printing plate. ing.

However, the monomer contained in the photosensitive layer is not substantially dissolved in the alkaline developing solution, and as the processing amount of the printing plate is increased, the insoluble matter remains in the developing solution, which causes the formation of oxygen. As the processing amount of the printing plate increases together with the dissolution of the overcoat layer such as polyvinyl alcohol, which is provided to prevent blocking, in the developing solution, the developing solution remarkably thickens and the developing processing ability decreases. It was a problem.

Further, JP-A-2-220062 and JP-A-2-20062
-219060, JP-A-2-217859, and JP-A-2-189544 disclose a method of developing a negative photosensitive lithographic printing plate comprising a diazo resin and a binder with an alkaline aqueous solution having a pH of 12 or more.

However, when a photosensitive lithographic printing plate comprising a diazo resin and a binder is developed with a high pH aqueous solution, the printing durability is deteriorated, or the developer penetrating into the image area is inferior in inking property. There are many problems.

By the way, as a photo-crosslinkable polymer, Japanese Patent Laid-Open No.
No. 2-988 (Japanese Patent Publication No. 60-37123) discloses a polymer having a dimethylmaleimide group, and JP-A No.
No. 78544 describes a photosensitive composition comprising the above polymer and a diazo resin.

However, the development of a photosensitive lithographic printing plate using these photosensitive compositions is almost always carried out using a developing solution containing an organic solvent. The reason for this is that when developed with a developer containing a high-pH silicate that does not contain an organic solvent, the developability is remarkably reduced, or an undeveloped residue is likely to occur, or conversely, when the developability of the polymer is increased. , Reduction in printing durability, which is the performance of a lithographic printing plate,
It may cause a decrease in sensitivity.

[0011]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to develop a negative-working photosensitive lithographic printing plate having a photocrosslinkable polymer with an aqueous solution containing an alkali metal silicate containing substantially no organic solvent. Another object of the present invention is to provide a method for producing a lithographic printing plate which is free from printing stains and has excellent printing durability.

[0012]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing a semiconductor device comprising the steps of:
Containing a co-condensed diazo resin containing an alkali water-soluble or swellable photocrosslinkable polymer having a maleimide group in the side chain, a sensitizer and an aromatic compound having at least one carboxyl group and an aromatic diazonium compound as constituent units In a method of producing a lithographic printing plate, which comprises a step of removing a photosensitive layer in an unexposed portion by imagewise exposing a photosensitive lithographic printing plate having a photosensitive layer provided on a support, the developing solution is , An alkali metal or ammonia silicate aqueous solution, and [SiO ₂ ] / [M] (provided that [Si 2
O ₂ ] indicates the molar concentration of SiO ₂ , and [M] indicates the molar concentration of alkali metal or ammonia. ) Is 0.25 to 0.75,
The method for producing a lithographic printing plate is characterized in that the concentration of SiO ₂ is 1.0 to 4.0% by weight based on the total weight of the developer.

The present invention will be described in detail below.

A polymer having a maleimide group in its side chain is disclosed in Japanese Patent Application Laid-Open No. 52-988 (corresponding US Pat.
No.), German Patent 2,626,769, European Patent
21,019, European Patent 3,522 and Die Angewandte Makromolekulare Chemie 115 (1
983), pages 163 to 181, the following general formula (A):

[0015]

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Wherein R ¹ and R ² each independently represent an alkyl group having up to 4 carbon atoms, or
R ¹ and R ² may combine together to form a 5- or 6-membered carbon ring), a polymer having a maleimide group represented by a side chain, and JP-A-49-128991 and JP-A-49-128.
No. 992, No. 49-128993, No. 50-5376.
No. 50, No. 50-5377, No. 50-5379, No. 50
-5378, 50-50380, 53-5298.
No. 53-5299, No. 53-5300, No. 50
-50107, 51-47940, 52-13
907, 50-45076, 52-12170.
No. 0, No. 50-10884, No. 50-45087,
The following general formula (B) described in German Patent Nos. 2,349,948 and 2,616,276:

[0017]

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(Wherein R ³ represents an aromatic group and R ⁴ represents a hydrogen atom, a halogen atom, an alkyl group or a cyano group), and the like may be a polymer having a maleimide group in its side chain. . These polymers have an average of 2 or more maleimide groups in the side chain per molecule.

In order to make these polymers having maleimide groups in their side chains soluble or swellable in alkaline water, inclusion of acid groups in the polymers can be achieved.

Specific examples of the acid group include pK which dissociates with carboxylic acid, sulfonic acid, phosphoric acid, phosphonic acid and their alkali metal salts or ammonium salts, and alkaline water.
a is 6 to 12 acid groups, specifically, -SO ₂ NHCO -, -
CONHCO -, - SO ₂ NHCOO-, and a 4-hydroxyphenyl group. The monomer having these acid groups and the monomer having a maleimide group are, for example, 10/90 to 50.
The photocrosslinkable polymer of the present invention can be easily obtained by copolymerizing at a ratio of / 50, preferably 20/80 to 40/60 (molar ratio).

The acid value of the maleimide polymer having an acid group is preferably in the range of 30 to 300, more preferably 50.
~ 250. Preferred examples of the copolymerizable monomer having an acid group include vinyl monomers having a carboxyl group such as acrylic acid and methacrylic acid, maleic anhydride, and itaconic anhydride.

Among the polymers having these acid values,
Dee Angebandute Macromolecule Kemi
ー (Die Angewandte Makromolekulare Chemie)128
(1984), pages 71-91.
N- [2-methacryloyloxy) alkyl] -2,
3-dimethylmaleimide and methacrylic acid or acrylic
Copolymers with acid are useful. In addition, the copolymer
Copolymerization of the third component vinyl monomer during formation
To easily synthesize multi-component copolymers according to purpose.
Can be. For example, the vinyl monomer of the third component
The homopolymer has a glass transition temperature below room temperature.
Use Killmethacrylate or alkyl acrylate
Thereby, flexibility can be given to the copolymer.

As the polymers used in the present invention, those having a weight average molecular weight of 1,000 or more, preferably 10,000 to 500,000, and particularly preferably 20,000 to 300,000 are desirable.

The amount of the photocrosslinkable polymer added to the photosensitive layer is 10 to 99% by weight (hereinafter abbreviated as%), preferably 50 to 99%.

The co-condensed diazo resin used in the present invention comprises an aromatic compound having at least one carboxyl group,
An aromatic diazonium compound represented by the following general formula (I) is included as a constitutional unit.

[0026]

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In the formula, R ⁵ represents a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, a carboxyester group or a carboxyl group, preferably a hydrogen atom and a carbon number of 1 to 1.
5 alkyl groups or hydroxyl groups are shown. R ⁶ represents a hydrogen atom, an alkyl group or an alkoxy group, preferably a hydrogen atom or an alkoxy group. R ³ represents a hydrogen atom, an alkyl group or an alkoxy group, preferably a hydrogen atom.

X ⁻ represents an anion, preferably an anion of an inorganic acid or an organic acid having a pKa of 4 or less. Specifically, hydrohalic acids such as hydrofluoric acid, hydrochloric acid, hydrochloric acid-zinc chloride complex, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid (pentavalent phosphorus), particularly orthophosphoric acid, Inorganic iso- and heteropolyacids such as phosphotungstic acid, phosphomolybdic acid, aliphatic or aromatic phosphonic acids or half esters thereof, arsonic acid, phosphinic acid, fluorocarboxylic acids such as trifluoroacetic acid, amidosulfonic acid, selenic acid , Hydrofluoric acid, hexafluorophosphoric acid, perchloric acid, and aliphatic and aromatic sulfonic acids, for example, fluoroalkanesulfonic acids such as methanesulfonic acid and trifluoromethanesulfonic acid, laurylsulfonic acid, dioctylsulfosuccinic acid, dicyclohexyl Sulfosuccinic acid, camphorsulfonic acid, tolyloxy-3-propane Sulfonic acid, nonyl phenoxy-3
Propanesulfonic acid, nonylphenoxy-4-butanesulfonic acid, dibutylphenoxy-3-propanesulfonic acid, diamylphenoxy-3-propanesulfonic acid, dinonylphenoxy-3-propanesulfonic acid, dibutylphenoxy-4-butanesulfonic acid , Dinonylphenoxy-4-butanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, mesitylenesulfonic acid, p-chlorobenzenesulfonic acid, 2,5-dichlorobenzenesulfonic acid, sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, p-Acetylbenzenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-chloro-5-nitrobenzenesulfonic acid, butylbenzene Zensulfonic acid, octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, butoxybenzenesulfonic acid, dodecyloxybenzenesulfonic acid, 2-methoxy-4-hydroxy-5-benzoylbenzenesulfonic acid, isopropylnaphthalenesulfonic acid, butylnaphthalenesulfonic acid, hexyl Naphthalenesulfonic acid, octylnaphthalenesulfonic acid, butoxynaphthalenesulfonic acid, dodecyloxynaphthalenesulfonic acid, dibutylnaphthalenesulfonic acid, dioctylnaphthalenesulfonic acid, triisopropylnaphthalenesulfonic acid, tributylnaphthalenesulfonic acid, 1-naphthol-5-sulfonic acid, Naphthalene-1-sulfonic acid,
Naphthalene-2-sulfonic acid, 1,8-dinitro-naphthalene-3,6-disulfonic acid, 4,4'-diazide-
Stilbene-3,3'-disulfonic acid, 1,2-naphthoquinone-2-diazide-4-sulfonic acid, 1,2-naphthoquinone-2-diazide-5-sulfonic acid and 1,2-
Included are the anions of naphthoquinone-2-diazide-4-sulfonic acid or mixtures of these anions.

Particularly preferred among these anions are dodecylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, methanesulfonic acid, and 2-methoxy-4.
-Hydroxy-5-benzoylbenzenesulfonic acid, anion of hexafluorophosphoric acid.

Y represents --NH--, --O--, or --S--, preferably --NH--.

Specific examples of the aromatic diazonium compound represented by the above general formula (I) include 4-diazodiphenylamine, 4'-hydroxy-, 4-diazodiphenylamine, 4'-methyl-4-diazodiphenylamine, 4 ′ -Ethyl-4-diazodiphenylamine, 4 ′
-N-propyl-4-diazodiphenylamine, 4'-
i-propyl-4-diazodiphenylamine, 4'-n
-Butyl-4-diazodiphenylamine, 4'-hydroxymethyl-4-diazodiphenylamine, 4'-β-
Hydroxyethyl-4-diazodiphenylamine, 4 '
-Γ-hydroxypropyl-4-diazodiphenylamine, 4'-methoxymethyl-4-diazodiphenylamine, 4'-ethoxymethyl-4-diazodiphenylamine, 4'-β-methoxyethyl-4-diazodiphenylamine, 4'-β -Ethoxyethyl-4-diazodiphenylamine, 4'-carboxy-4-diazodiphenylamine, 3-methyl-4-diazodiphenylamine, 3
-Ethyl-4-diazodiphenylamine, 3'-methyl-4-diazodiphenylamine, 3,3'-dimethyl-
4-diazodiphenylamine, 2'-carboxy-4-
Diazodiphenylamine, 4-diazodiphenyl ether, 4'-methyl-4-diazodiphenyl ether,
3,4'-dimethyl-4-diazodiphenyl ether,
4'-carboxy-4-diazodiphenyl ether,
3,3'-dimethyl-4-diazodiphenyl ether,
4-diazodiphenyl sulfide, 4'-methyl-4-
Examples thereof include salts such as diazodiphenyl sulfide.

Of these, a particularly preferred aromatic diazonium compound is a 4-diazodiphenylamine salt.

The aromatic compound having at least one carboxyl group according to the present invention contains an aromatic ring having at least one carboxyl group in the molecule. In this case, a part of the carboxyl group may be substituted with an aromatic ring. Preferred examples of the above aromatic ring include a phenyl group and a naphthyl group.
The above-mentioned carboxyl group may be directly bonded to the aromatic ring, or may be bonded via a linking group. In the present invention, the number of carboxyl groups bonded to one aromatic ring is preferably from 1 to 3. Further, examples of the linking group include an alkylene group having 1 to 4 carbon atoms.

In order to condense the above-mentioned aromatic compounds with aldehydes or ketones, it is necessary to have at least two non-substituted sites on the aromatic ring of one or more aryl groups.

Specific examples of the aromatic compound having a carboxyl group in the molecule used in the present invention include salicylic acid, 4-methylsalicylic acid, 6-methylsalicylic acid and 4
-Ethylsalicylic acid, 6-propylsalicylic acid, 6-laurylsalicylic acid, 6-stearylsalicylic acid, 4,6
-Dimethylsalicylic acid, p-hydroxybenzoic acid, 2-
Methyl-4-hydroxybenzoic acid, 6-methyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,4-dihydroxy-6-methylbenzoic acid, 2,6-dihydroxybenzoic acid, 2,6-dihydroxy-4-methylbenzoic acid, 4-chloro-2,6-dihydroxybenzoic acid, 4-
Methoxy-2,6-dioxybenzoic acid, gallic acid, phloroglucincarboxylic acid, 2,4,5-trihydroxybenzoic acid, m-galloyl gallic acid, tannic acid, m-benzoyl gallic acid, m- (p- Toluyl) gallic acid, protocatechuyl gallic acid, 4,6-dihydroxyphthalic acid, (2,4-dihydroxyphenyl) acetic acid, (2,2
6-dihydroxyphenyl) acetic acid, (3,4,5-trihydroxyphenyl) acetic acid, phenoxyacetic acid, p-hydroxymethylbenzoic acid, p-hydroxyethylbenzoic acid, 4- (p-hydroxyphenyl) methylbenzoic acid,
4- (o-hydroxybenzoyl) benzoic acid, 4-
(2,4-dihydroxybenzoyl) benzoic acid, 4-
(P-hydroxyphenoxy) benzoic acid, 4- (p-hydroxyanilino) benzoic acid, bis (3-carboxy-
4-hydroxyphenyl) amine, 4- (p-hydroxyphenylsulfonyl) benzoic acid, 4- (p-hydroxyphenylthio) benzoic acid, p-methoxybenzoic acid,
2,4-dimethoxybenzoic acid, 2,4-dimethylbenzoic acid, p-phenoxybenzoic acid, p-methoxyphenylacetic acid, 4-anilinobenzoic acid, 4- (m-methoxyanilino) benzoic acid, 4- (p -Methoxybenzoyl) benzoic acid, 4- (p-methylanilino) benzoic acid, 4-phenylsulfonylbenzoic acid and the like can be mentioned. Of these, particularly preferred are 2,4-dimethoxybenzoic acid, p-phenoxybenzoic acid, 4-anilinobenzoic acid,
4- (m-methoxyanilino) benzoic acid, 4- (p-methylanilino) benzoic acid, salicylic acid, p-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, gallic acid,
Phloroglucin carboxylic acid, phenoxyacetic acid and 4-
(P-hydroxyanilino) benzoic acid.

The co-condensed diazo resin containing an aromatic compound having at least one carboxyl group and an aromatic diazonium compound as constitutional units in the present invention is a known method, for example, Photographic Science and Engineering (Photo). .S ci., Eng.) Vol. 17, p. 33 (1973), U.S. Pat. Nos. 2,063,631 and 2,
According to the method described in each specification of 679, 498, sulfuric acid, phosphoric acid, an aromatic diazonium compound in hydrochloric acid, an aromatic compound having a carboxyl group, and aldehydes, such as paraformaldehyde, acetaldehyde, benzaldehyde or ketones, for example, It is obtained by polycondensation with acetone and acetophenone.

The aromatic compound having a carboxyl group in the molecule, the aromatic diazonium compound and the aldehydes or ketones can be freely combined with each other, and two or more kinds of them can be mixed and co-condensed. is there.
Furthermore, cocondensable phenols having no carboxyl group can be added for cocondensation.

At this time, the charged molar ratio of the aromatic compound having a carboxyl group and the aromatic diazonium compound is
1: 0.1-0.1: 1, preferably 1: 0.2-0.2-1,
More preferably, the ratio is 1: 0.5 to 0.2: 1. Further, in this case, the total amount of the aromatic compound having a carboxyl group and the aromatic diazonium compound and the aldehyde or the ketone are in a molar ratio of usually 1: 0.6 to 1.2, preferably 1: 0.7 to.
The co-condensed diazo resin is obtained by charging at 1.5 and reacting at low temperature for a short time, for example, for about 3 hours.

Specific examples of the co-condensed diazo resin in the present invention include salicylic acid-4-diazodiphenylamine.
Hexafluorophosphate-formaldehyde resin, 4-methylsalicylic acid-4-diazo-4'-methyldiphenylamine hexafluorophosphate-formaldehyde resin, p-hydroxybenzoic acid-4-diazodiphenylamine / hexafluorophosphoric acid Salt-formaldehyde resin, p-hydroxybenzoic acid-4-diazo-3-methyldiphenylamine / hexafluorophosphate-formaldehyde resin, gallic acid-4
-Diazo-4'-ethyldiphenylamine-2-hydroxy-4-methoxybenzophenone-5-sulfonate-formaldehyde resin, 2,4-dihydroxybenzoic acid-4-diazodiphenylamine hexafluorophosphate-formaldehyde resin, 4 -(P-hydroxyanilino)
Benzoic acid-4-diazodiphenylamine / hexafluorophosphate-formaldehyde resin, 3-methoxy-1,2-
Benzenedicarboxylic acid-4-diazo-3-methyldiphenylamine / hexafluorophosphate-benzaldehyde resin, p-methoxybenzoic acid-4-diazodiphenylamine / hexafluorophosphate-formaldehyde resin, 2-methylbenzoic acid- 4-diazodiphenylamine / hexafluorophosphate-formaldehyde resin, p-phenoxybenzoic acid-4-diazodiphenylamine-2-hydroxy-
4-Methoxybenzophenone-5-sulfonate-formaldehyde resin, 2,4-diaminobenzoic acid-4-diazodiphenylamine / hexafluorophosphate-formaldehyde resin, 2,4-dimethoxybenzoic acid-4-diazo-4 ′ -Methyldiphenylamine / hexafluorophosphate-
Formaldehyde resin, 4-carboxydiphenylamine-4-diazo-4'-ethyldiphenylamine / hexafluorophosphate-formaldehyde resin, 2,4-dimethoxybenzoic acid-4-diazodiphenylamine / hexafluorophosphate-formaldehyde resin , 4-anilinobenzoic acid-4-diazo-4'-methyldiphenylamine-hexafluorophosphate-formaldehyde resin, p-phenoxybenzoic acid-4-diazodiphenylamine-hexafluorophosphate-formaldehyde resin, etc. Among these compounds, particularly preferable are salicylic acid-4-diazodiphenylamine-2-hydroxy-4-methoxybenzophenone-5-sulfonate-formaldehyde resin,
p-Methoxybenzoic acid-4-diazodiphenylamine
Dodecylbenzene sulfonate-formaldehyde resin, 2,4-dimethoxybenzoic acid-4-diazodiphenylamine-2-hydroxy-4-methoxybenzophenone-5-sulfonate-formaldehyde resin, 4-anilinobenzoic acid-4-diazodiphenylamine -Methanesulfonate-formaldehyde resin, p-phenoxybenzoic acid-4-diazo-4'-methyldiphenylamine-dodecylbenzenesulfonate-formaldehyde resin, 2,4-dihydroxybenzoic acid-4-diazodiphenylamine-dibutylnaphthalenesulfone Acid salt-formaldehyde resin, 4-carboxydiphenylamine-4
-Diazodiphenylamine / methanesulfonate-formaldehyde resin, 4-carboxy-4'-methoxydiphenylamine-4-diazodiphenylamine-2-hydroxy-4-methoxybenzophenone-5-sulfonate-formaldehyde resin, phenoxyacetic acid-4- It is a diazodiphenylamine dodecylbenzene sulfonate-formaldehyde resin.

The molecular weight of the co-condensed diazo resin of the present invention can be obtained as an arbitrary value by variously changing the molar ratio of each monomer and the condensation conditions, but it is effective for the intended purpose of the present invention. For this purpose, those having a molecular weight of about 400 to 100,000 can be used. Preferably about 8
Those of 00 to 5,000 are suitable.

When this co-condensed diazo resin is contained in the photosensitive layer, the content is 0.1 to 30% by weight, preferably 1
10 to 10% by weight. More preferably, it is 2 to 5% by weight.

In addition to the co-condensed diazo resin used in the present invention, JP-B-47-1167 and JP-A-50-11.
8802, Japanese Patent Publication No. 49-48001, Japanese Patent Publication No. 52-
7364, JP-A-59-222834, JP-A-1
-102456, JP-A-1-102457, JP-A-1-245246, Japanese Patent Application No. 1-130493, Japanese Patent Application No. 2-53101, etc., and a diazo resin as described in the present invention. You may use together with a diazo resin.

The sensitizer used in the present invention is 300
A triplet sensitizer having a maximum absorption that allows practically sufficient light absorption in the range of nm or more is preferable.

Examples of such sensitizers include benzophenone derivatives, benzanthrone derivatives, quinones, aromatic nitro compounds, naphthothiazoline derivatives, benzothiazoline derivatives, thioxanthones, naphthothiazole derivatives, ketocoumarin compounds, benzothiazole derivatives, naphthofuranone compounds. , Pyrylium salts, thiapyrylium salts and the like. Specifically, Michler's ketone,
N, N'-diethylaminobenzophenone, benzanthrone, (3-methyl-1,3-diaza-1,9-benz) anthrone picramide, 5-nitroacenaphthene,
2-chlorothioxanthone, 2-isopropylthioxanthone, dimethylthioxanthone, methylthioxanthone-1-ethylcarboxylate, 2-nitrofluorene, 2-dibenzoylmethylene-3-methylnaphthothiazoline, 3,3-carbonyl-bis (7-diethylamino) Coumarin), 2,4,6-triphenylthiapyrylium perchlorate and 2- (p-chlorobenzoyl) naphthothiazole, as well as JP-B-45-8832, JP-A-52-129791, and JP-A-62. -294238,
JP-A-2-173646, JP-A-2-131236
No., European Patent No. 368327, JP-A-2-236552.
And the sensitizers described in Japanese Patent Application No. 1-190963. The amount of these sensitizers added is about 1 to about 20% by weight of the photosensitive layer, and more preferably 3%.
10 to 10% by weight is suitable.

The photosensitive layer of the present invention may further contain a binder, if desired, and it is usually appropriately selected from linear organic polymers. Specific examples of the binder include chlorinated polyethylene, chlorinated polypropylene, polyacrylic acid alkyl ester; copolymer having at least one kind of monomer such as acrylic acid alkyl ester, acrylonitrile, vinyl chloride, styrene and butadiene as a constitutional unit. , Polyamide, methyl cellulose, polyvinyl formal, polyvinyl butyral, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer and the like.

In some cases, for the purpose of coloring the photosensitive layer, a dye or pigment, a pH indicator as a printout agent, a leuco dye, a photoacid generator, a diazo monomer and the like can be added.

The photosensitive layer of the present invention may contain a plasticizer and the like. As the plasticizer, dialkyl phthalate such as dibutyl phthalate and dihexyl phthalate, oligoethylene glycol alkyl ester, phosphate plasticizer and the like can be used. Further, various acid compounds as stabilizers for diazo resins and acid group-containing compounds soluble in alkaline water for promoting development may be used.

Further, in the present invention, the properties of the surface of the photosensitive layer can be changed by adding an oil sensitizer, a surfactant, a fluorine compound, a silica compound and the like.

Further, it is preferable to add a thermal polymerization inhibitor and an antioxidant to the photosensitive layer. For example, hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol. , Benzoquinone, 4,4'-thiobis (3-methyl-6-t-
Butylphenol), 2,2′-methylenebis (4-methyl-6-t-butylphenol), 2-mercaptobenzimidazole, etc. are useful.

For the above-mentioned photosensitive layer, a photosensitive composition comprising each of the above components is prepared, for example, by using 2-methoxyethanol, 2-methoxyethyl acetate, methyl cellosolve, propylene glycol monomethyl ether, 3-methoxypropanol, 3-methoxypropyl. Acetate, acetone,
Methyl ethyl ketone, ethylene dichloride, methyl lactate, ethyl lactate, methanol, dimethylformamide,
It is formed by dissolving a suitable solvent such as ethanol, methyl cellosolve acetate, diethylene glycol monoalkyl ether, and diethylene glycol alkyl ether alone or in a mixed solvent in which these are appropriately combined and coating it on a support. The coating amount in the range of about 0.1 g / m ² ~ about 10 g / m ² in weight after drying are suitable, preferably from 0.5 to 5 g / m ^2.

In the present invention, an intermediate layer is optionally added for the purpose of increasing the adhesion between the support and the photosensitive layer, preventing the photosensitive layer from remaining after development, or preventing halation. It may be provided. In order to improve the adhesion, the intermediate layer generally comprises a diazo resin, a phosphoric acid compound adsorbed on aluminum, a silane coupling agent, or the like. The intermediate layer made of a highly soluble substance so that the photosensitive layer does not remain in the developing solution is generally made of a polymer having a good solubility or a water-soluble polymer. Furthermore, for antihalation, the intermediate layer generally contains dyes and UV absorbers. The thickness of the intermediate layer is arbitrary, and must be a thickness capable of performing a uniform bond-forming reaction with the upper photosensitive layer upon exposure. Usually about 1 to 1 as a dry solid
Applying a rate of 200 mg / m ² good, 5 to 40 mg / m ² is particularly favorable.

The intermediate layer may contain the co-condensed diazo resin used in the photosensitive layer of the present invention or a photo-crosslinking polymer. The proportion of these used is 10 to 100% by weight, preferably 30 to 100% by weight.

If desired, the intermediate layer may contain various additives in addition to the sensitizer, diazo stabilizer, polymer binder, antihalation agent and surfactant.

In order to form the intermediate layer, the above compound is dissolved in an arbitrary solvent at a desired concentration, and it is applied or dipped,
It is then obtained by drying.

The surface of the photosensitive layer of the present invention may be further subjected to a matting process in order to enhance the adhesion to the film.
For these, compounds and methods described in JP-A-55-12974 and JP-A-58-182636 can be used.

The support having a hydrophilic surface used in the present invention is preferably a dimensionally stable plate-like material. Such dimensionally stable plate-like materials include those conventionally used as a support for a printing plate, and they can be suitably used in the present invention. Examples of such a support include paper, paper laminated with plastics (eg, polyethylene, polypropylene, polystyrene, etc.),
Metal plates such as aluminum (including aluminum alloys), zinc, copper, etc., cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose acetate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, Examples include plastic films such as polycarbonate and polyvinyl acetal, and paper or plastic films on which the above-mentioned metals are laminated or vapor-deposited. Among these supports, the aluminum plate is preferable because it is extremely stable in dimension, is inexpensive, and has particularly good adhesion to the photosensitive layer of the present invention. Further, a composite sheet in which an aluminum sheet is bonded to a polyethylene terephthalate film as described in JP-B-48-18327 is also preferable.

In the case of a metal, particularly an aluminum support, it is preferable that surface treatment such as graining treatment and anodic oxidation treatment is performed.

In order to enhance the hydrophilicity of the surface, it is preferable to carry out a dipping treatment in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate or the like. U.S. Patent No.
As described in Japanese Patent No. 2,714,066, an aluminum plate that has been grained and then immersed in an aqueous sodium silicate solution, and after anodizing the aluminum plate as described in JP-B-47-5125, Those obtained by immersion treatment in an aqueous solution of an alkali metal silicate are also preferably used.

Also, silicate electrodeposition as described in US Pat. No. 3,658,662 is effective. Furthermore, Japanese Examined Patent Publication No. 46-27481 and Japanese Unexamined Patent Publication No. 52-58.
A surface treatment in which a support subjected to electrolytic graining as disclosed in JP-A No. 602 and JP-A No. 52-30503 is combined with the anodizing treatment and sodium silicate treatment is also useful.

Further, as disclosed in Japanese Patent Laid-Open No. 56-28893, brush grains, electrolytic grains,
It is also preferable that the anodic oxidation treatment and the sodium silicate treatment are sequentially performed. It is also preferable that after these treatments, a water-soluble resin, such as polyvinyl phosphonic acid, a polymer or copolymer having a sulfonic acid group in its side chain, is undercoated. Furthermore, JP-A-2-23
The ones disclosed in Japanese Patent Application No. 348/1989 and Japanese Patent Application No. 2-151858 are also suitable.

These hydrophilization treatments are carried out to make the surface of the support hydrophilic, as well as to prevent harmful reaction with the photosensitive composition provided thereon and with the photosensitive layer. It is applied to improve adhesion.

The developing solution used in the present invention will be described in detail. Examples of alkali metal or ammonia silicates (hereinafter simply referred to as “alkali metal silicates”) used in the present invention include sodium silicate, potassium silicate, lithium silicate, ammonium silicate, and the like.
It is potassium silicate. Alkali metal silicate solution [Si
O ₂ ] / [M] is 0.25 to 0.75, and the SiO ₂ concentration is 1.0 to 4.0% by weight based on the total weight.

When [SiO ₂ ] / [M] is 0.25 or less,
The non-image area and the aluminum on the back surface are etched,
In some cases, it will foam. Also, [SiO ₂ ] /
When the [M] ratio is 0.75 or more, the developability of the photosensitive layer in the non-image area is likely to be deteriorated, and stains are likely to occur during printing.

On the other hand, when the SiO ₂ concentration is less than 1.0% by weight, the pH is lowered due to the effect of CO _{2 in} the air, and the activity of the developer is likely to change. On the other hand, if it is more than 4.0% by weight, the developability of the non-image area is deteriorated, and the undeveloped area is liable to cause print stains.

Furthermore, other alkaline agents can be used in the developing solution, if necessary. Such alkaline agents include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium phosphate tribasic, sodium phosphate dibasic, ammonium phosphate tribasic, ammonium phosphate dibasic, sodium metasilicate, bicarbonate. Inorganic alkaline agents such as sodium and ammonia, and organic amine compounds such as monoethanolamine, diethanolamine, triethanolamine, mono-, di-, and trialkylamines can be used, and these can be used alone or in combination. Good.

If necessary, a surfactant, an organic solvent or the like can be added to this aqueous solution.

Examples of the anionic surfactants include higher alcohol sulfates having 8 to 22 carbon atoms such as sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, and sodium salt of secondary sodium alkyl sulfate. , Aliphatic alcohol sulfate salts such as, for example, sodium salt of cetyl alcohol sulfate, alkylaryl such as sodium salt of dodecylbenzenesulfonic acid, sodium salt of isopropylnaphthalenesulfonic acid, sodium salt of metanitrobenzenesulfonic acid, etc. Sulfonates,
For example, alkyl amide sulfonates such as C ₁₇ H ₃₃ CON (CH ₃ ) CH ₂ CH ₂ SO ₃ Na, and dibasic fatty acid esters such as sodium sulfosuccinate dioctyl ester and sodium sulfosuccinate dihexyl ester. Sulfonates and the like are included.

Examples of the amphoteric surfactant include alkylcarboxybetaine type alkylaminocarboxylic acid type compounds, alkylimidazoline type compounds and Japanese Patent Publication No. 1-578.
The organic boron compounds disclosed in No. 95 are included. Further, JP-A-62-168160 and JP-A-62-168160
Nonionic surfactants disclosed in JP-A-175758 and cationic surfactants disclosed in JP-A No. 62-175757 are included.

It is appropriate that the surfactant is contained in the range of 0 to 5% by weight based on the total weight of the developing solution at the time of use. As the organic solvent, those having a solubility in water of about 10% by weight or less are suitable, and those having a solubility of 2% by weight or less are preferable. For example, 1-phenylethanol, 2-phenylethanol, 3-phenylpropanol-1, 4-phenylbutanol-1, 4-phenylbutanol-2, 2-phenylbutanol-1, 2-phenoxyethanol, 2-benzyloxyethanol, o
-Methoxybenzyl alcohol, m-methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 4-methylcyclohexanol and 3-
Methylcyclohexanol and the like can be mentioned.

The content of the organic solvent is preferably 0 to 1% by weight based on the total weight of the developing solution at the time of use. The amount used is closely related to the amount used of the surfactant, and it is preferable to increase the amount of the surfactant as the amount of the organic solvent increases.

Further, if necessary, an alkali-soluble mercapto compound and / or thioether compound,
Additives such as water-soluble reducing agents, defoamers and water softeners,
A colorant or the like can be included.

Examples of the water softener include Na ₂ P ₂ O ₇ and Na ₅ P
Polyphosphates such as ₃ O ₃ , Na ₃ P ₃ O ₉ , Na ₂ O ₄ P (NaO ₃ P) PO ₃ Na ₂ and Calgon (sodium polymetaphosphate), for example ethylenediaminetetraacetic acid, its potassium salt, its sodium salt Diethylenetriaminepentaacetic acid, its potassium salt, sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt; hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its potassium salt, its sodium salt 1,2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt; 1,3-
Mention may be made of aminopolycarboxylic acids such as diamino-2-propanoltetraacetic acid, its potassium salt, its sodium salt and the like.

The optimum amount of such a water softener varies depending on the hardness of the hard water used and the amount of the hard water used. 5
%, More preferably 0.01 to 0.5% by weight.

Examples of the water-soluble reducing agent include phenolic compounds such as hydroquinone and methoxyquinone, amine compounds such as phenylenediamine and phenylhydrazine, or sulfite salts such as sodium sulfite, potassium sulfite and sodium hydrogen sulfite, and potassium phosphite. Examples thereof include phosphites such as potassium hydrogen phosphite, sodium thiosulfate, and sodium dithionite.
The content is preferably 0.01 to 10% by weight based on the total weight of the developer.

Alkali-soluble mercapto compound and /
Alternatively, the thioether compound is preferably a compound having at least one mercapto group and / or thioether group in the molecule and at least one acid group, and further, at least one mercapto group in one molecule. And compounds having a carboxyl group are preferred. For example, mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 4-mercaptobutanoic acid, 2,4-dimercaptobutanoic acid, 2-mercaptotetradecanoic acid, 2
-Mercaptomyristic acid, mercaptosuccinic acid, 2,
3-dimercaptosuccinic acid, cysteine, N-acetylcysteine, N- (2-mercaptopropionyl) glycine, N- (2-mercapto-2-methylpropionyl) glycine, N- (3-mercaptopropionyl) glycine, N- ( 2-mercapto-2-methylpropionyl) cysteine, penicillamine, N-acetylpenicillamine, glycine / cysteine / glutamine condensate, N-
(2,3-dimercaptopropionyl) glycine, 2-
Mercaptonicotinic acid, thiosalicylic acid, 3-mercaptobenzoic acid, 4-mercaptobenzoic acid, 3-carboxy-2-mercaptopyridine, 2-mercaptobenzothiazole-5-carboxylic acid, 2-mercapto-3-phenylpropenoic acid, 2 -Mercapto-5-carboxyethylimidazole, 5-mercapto-1- (4-carboxyphenyl) tetrazole, N- (3,5-dicarboxyphenyl) -2-mercaptotetrazole, 2- (1,
2-dicarboxyethylthio) -5-mercapto-1,
3,4-thiadiazole, 2- (5-mercapto-1,
3,4-thiadiazolylthio) hexanoic acid, 2-mercaptoethanesulfonic acid, 2,3-dimercapto-1-propanesulfonic acid, 2-mercaptobenzenesulfonic acid, 4-mercaptobenzenesulfonic acid, 3-mercapto-4 -(2-sulfophenyl) -1,2,4-triazole, 2-mercaptobenzothiazole-5-sulfonic acid, 2-mercaptobenzimidazole-6-sulfonic acid, mercaptosuccinimide, 4-mercaptobenzenesulfonamide, 2 -Mercaptobenzimidazole-5-sulfonamide, 3-mercapto-4- (2-
(Methylaminosulfonyl) ethoxy) toluene, 3-
Mercapto-4- (2- (methylsulfonylamino) ethoxy) toluene, 4-mercapto-N- (P-methylphenylsulfonyl) benzamide, 4-mercaptophenol, 3-mercaptophenol, 3,4-dimethylcaptotoluene, 2 -Mercaptohydroquinone, 2-
Thiouracil, 3-hydroxy-2-mercaptopyridine, 4-hydroxythiophenol, 4-hydroxy-
2-mercaptopyrimidine, 4,6-dihydroxy-2
-Mercaptopyrimidine, 2,3-dihydroxypropyl mercaptan, tetraethylene glycol, 2-mercapto-4-octylphenyl ether methyl ether, 2-mercapto-4-octylphenol methanesulfonylaminoethyl ether, 2-mercapto-4-
Octylphenol methylaminosulfonyl butyl ether thiodiglycolic acid, thiodiphenol, 6,8-
Examples thereof include dithiooctanoic acid or its alkali metal, alkaline earth metal, and salts with organic amines. These may be used alone or as a mixture. Among these, especially thiosalicylic acid, N- (2,3-dimercaptopropionyl) glycine, 2- (1,2-dicarboxyethylthio) -5-mercapto-1,3,4-thiadiazole, 4-mercaptobenzene. Sulfonic acid, N- (2-mercapto-2-methylpropionyl) cysteine, cysteine and the like are preferable. The content in the developer composition is 0.001% to 10% by weight, preferably 0.01% to 5% by weight.

As a method for developing a photosensitive lithographic printing plate imagewise exposed with the above-mentioned developing solution, the developing solution is charged in a developing tank and the photosensitive lithographic printing plate is immersed in this developing solution. A method of repeatedly using a developing solution such as a method of passing it through or a method of spraying a developing solution in a developing tank, or JP-A-61-243455 and JP-A-62-62455.
No. 2254, a photosensitive lithographic printing plate as disclosed in No. 2254 is provided with an amount of a developing solution necessary for developing the plate surface,
After developing with only the applied developing solution, various methods such as a disposable developing method in which the developing solution is discarded and not reused are possible, but in the present invention, a method of repeatedly using the developing solution is used. In this case, it is preferable to add the developing replenisher continuously or intermittently. The composition of the developing solution and the replenishing solution and the replenishing method of the developing method for performing such replenishment are described in JP-A-54-62004 and 55-55.
22759, 55-115039, 56-12
645, 58-95349, 64-21451.
JP-A-1-180548 and JP-A-2-3065, and can be preferably used in the developing method of the present invention.

The imagewise exposure is carried out by using a light-sensitive lithographic printing plate with a light source rich in ultraviolet rays such as a metal halide lamp and a high pressure mercury lamp, and then treating with the above-mentioned developing solution to remove the unexposed portion of the photosensitive layer, If necessary, a desensitizing treatment after washing or a desensitizing treatment as it is or a treatment with an aqueous solution containing an acid is performed, and then desensitizing treatment is performed to obtain a printing plate.

[0078]

According to the present invention, a negative photosensitive lithographic printing plate is developed with an aqueous silicate alkali solution containing substantially no organic solvent, whereby it is free from stains and has excellent printing durability and sensitivity. , A lithographic printing plate can be obtained.

That is, the negative photosensitive lithographic printing plate can be processed by the same process as the conventional positive photosensitive lithographic printing plate to produce a lithographic printing plate.

Therefore, it is possible to process two types of negative and positive type photosensitive lithographic printing plates by using one type of developing solution and one automatic developing machine.

[0081]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by these examples. Example 1 An aluminum plate having a thickness of 0.30 mm and a nylon brush and 40
The surface was sand-grained using a 0-mesh pumistone aqueous suspension, and then thoroughly washed with water. It was immersed in 10% sodium hydroxide at 70 ° C. for 60 seconds for etching, washed with running water, neutralized with 20% HNO ₃ and washed with water. This was subjected to electrolytic surface roughening treatment in a 1% aqueous nitric acid solution at an anode electricity of 160 coulomb / dm ² using a sinusoidal alternating waveform current under the condition of V _A = 12.7 V. When the surface roughness was measured, it was 0.6 μ (Ra display). 30 in succession
% H ₂ SO ₄ aqueous solution and desmutted at 55 ° C. for 2 minutes, and then in 20% H ₂ SO ₄ aqueous solution, current density 2 A /
Anodizing treatment was performed for 2 minutes so that the thickness was 1.5 g / m ² in dm ² . Next, after immersing in a 2.5% aqueous solution of sodium silicate at 70 ° C. for 1 minute, washing with water and drying, the following photosensitive composition I was dried on the above support using a spin coater. A negative-working photosensitive lithographic printing plate was produced by applying the solution so that the weight of the latter was 1.5 g / m ^2, and then drying at 80 ° C. for 2 minutes.

Photosensitive composition I: Methyl methacrylate / N- [6- (methacryloyloxy) hexyl] -2,3-dimethylmaleimide / methacrylic acid = 10/60/30 (molar ratio) copolymer [Mw = 3 0.5 × 10 ⁴ (GPC) Tg = about 40 ° C. (DSC)] 5 g Sensitizer I represented by the following structural formula: 0.25 g

[0083]

Embedded image

Dodecylbenzene sulfonate of formaldehyde co-condensate of 4-diazodiphenylamine and phenoxyacetic acid 0.20 g Propylene glycol monomethyl ether 50 g Methyl ethyl ketone 50 g Megafac F-177 (Dainippon Ink and Fluorine nonionic interface) Activator) 0.03 g Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.10 g

The negative photosensitive lithographic printing plate thus obtained was contact-exposed through a negative film and a step wedge (density difference 0.15, density step number 15 steps).
The exposure was performed by irradiating a 2 kw ultra-high pressure mercury lamp for 60 seconds. Then, development was carried out at 25 ° C. for 30 seconds in an aqueous potassium silicate solution having a [SiO ₂ ] / [K] molar ratio of 0.5 and a SiO ₂ concentration of 1.5 wt%. After washing with water, a gum solution was applied and printing was performed with a KORD printing machine. As a result, 50,000 sheets of printed matter having no stain on the non-image area were obtained.

Example 2 After electrolytically surface-roughening the support of Example 1, it was subsequently immersed in a 30% H ₂ SO ₄ aqueous solution, desmutted at 55 ° C. for 2 minutes, and then 20% H 2. Anodizing treatment was performed for 5 minutes in an aqueous ₂ SO ₄ solution so that the amount of anodized film was 2.0 g / m ² at a current density of 2 A / dm ² . Then, it is immersed in a 2.5% aqueous solution of sodium silicate at 70 ° C. for 1 minute, washed with water, and dried, and then the following photosensitive composition II is dried on the above support using a spin coater. A photosensitive lithographic printing plate was produced by applying the solution so that the weight of the latter was 1.5 g / m ² and then drying at 80 ° C. for 2 minutes.

Photosensitive composition II: N- [2- (methacryloyloxy) ethyl] -2,3-dimethylmaleimide / methacrylic acid = 65/35 (molar ratio) copolymer (Mw = 2.5 × 10 ⁴ ) 5 g of the following sensitizer II: 0.2 g

[0088]

Embedded image

Hexafluorophosphate of formaldehyde cocondensation of salicylic acid and 4-diazo-3-methoxydiphenylamine 0.1 g 4-diazodiphenylamine (diazomonomer) 0.03 g phosphorous acid (50% aqueous solution) 0 .05 g Propylene glycol monomethyl ether 50 g Methyl ethyl ketone 50 g Megafac F-177 0.03 g Oil blue 03 (Orient Chemical Industry Co., Ltd.) 0.15 g

Then, in the same manner as in Example 1, this negative type photosensitive lithographic printing plate was exposed to light and was exposed to 25 by an automatic processor (PS800E manufactured by Fuji Photo Film Co., Ltd.) using the following developer.
It was developed at 40 ° C. for 40 seconds and gummed.

The gum solution is FN manufactured by Fuji Photo Film Co., Ltd.
-2 was used.

The developing solution [SiO ₂ ] / [K] has a molar ratio of 0.55 and SiO ₂
0.1% by weight of the surfactant Perex NBL (manufactured by Kao Atlas) is contained in an aqueous potassium silicate solution having a concentration of 2.0% by weight.

Printing was carried out in the same manner as in Example 1 using the obtained lithographic printing plate, and 60,000 sheets of stain-free printed matter were obtained.

Example 3 The following undercoat liquid was applied and dried on a support treated in the same manner as in Example 2. The coating amount was 10 mg / m ^{2 as a} dry weight.

Undercoating liquid: C.I.Acid Yellow 25 0.25 g Methanol 50 g Pure water 100 g

Then, the following photosensitive composition III was prepared in the same manner as in Example 1.
Coating and drying were carried out in the same manner as in 1. to produce a photosensitive lithographic printing plate.

Photosensitive Composition III: N- [6- (methacryloyloxy) hexyl] -2,3-dimethylmaleamide / methacrylic acid = 70/30 (molar ratio) copolymer (Mw = 8.0 ×) 10 ⁴ ) 5.0 g Sensitizer III below: 0.3 g

[0098]

Embedded image

Butyl naphthalene sulfonate of formaldehyde co-condensate of benzoic acid and 4-diazodiphenylamine 0.1 g 1,3-bis (trichloromethyl) -5-phenyl-s-triazine 0.1 g malic acid 0.05 g phenyl Phosphonic acid 0.05 g Oil blue # 603 (Orient Chemical Industry Co., Ltd.) 0.10 g Propylene glycol monomethyl ether 50 g Methyl ethyl ketone 30 g Methanol 20 g Megafac F177 0.03 g

Then, in the same manner as in Example 1, the negative photosensitive lithographic printing plate was exposed to light, and the following developing solution was used, and it was stored in an automatic processor (Fuji Photo Film Co., Ltd. PS900D) at 30 ° C. for 1 hour.
It was developed for 2 seconds and gummed.

The developer [SiO ₂ ] / [Na] has a molar ratio of 0.4 and SiO ₂
Sodium silicate solution with a concentration of 1.5% by weight

The obtained printing plate was printed in the same manner as in Example 1 to obtain 50,000 clean printed matters without stains.

[0103]

Comparative Example The photosensitive lithographic printing plate obtained in Example 1
When developed with an aqueous solution of potassium silicate having a molar ratio of [io ₂ ] / [K] of 0.8 and a SiO ₂ concentration of 4.5% by weight, the developability of the non-image area was low and the film was removed like sludge. .

Claims (1)

(57) [Claims] 1. An alkali water-soluble or swellable photocrosslinkable polymer having a maleimide group as a side chain, a sensitizer, and an aromatic compound having at least one carboxyl group and an aromatic diazonium compound are provided on a support. A method for producing a lithographic printing plate including a step of removing a photosensitive layer in an unexposed portion by imagewise exposing a photosensitive lithographic printing plate provided with a photosensitive layer containing a co-condensed diazo resin contained as a constituent unit In the above, the developing solution comprises an aqueous solution containing an alkali metal or ammonia silicate, and [SiO ₂ ] /
[M] (where [SiO ₂ ] is the molar concentration of SiO ₂ ,
[M] indicates the molar concentration of alkali metal or ammonia. ) Is 0.25 to 0.75, and the concentration of SiO ₂ is 1.0 to 4.0% by weight with respect to the total weight of the developing solution.