JP2684251B2 - 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.

[0002]

2. Description of the Related Art In general, a photosensitive printing plate is prepared by coating a photosensitive composition on a support such as an aluminum plate and irradiating an actinic ray such as ultraviolet rays through a negative image or the like to polymerize the irradiated portion. Crosslink and insolubilize in the developing solution, elute the non-irradiated portion of the light into the developing solution, and separate each portion of the image portion that repels water to receive the oil-based ink and the non-image portion that receives water to repel the oil-based ink. It is obtained by forming an image part.

In this case, the photosensitive composition includes:
Diazo resins such as condensates of p-diazodiphenylamine and formaldehyde have been widely used. On the other hand, when the photosensitive lithographic printing plate using these diazo resins is developed after exposure, examples of the aqueous alkaline developer composition used include, for example, benzyl alcohol, disclosed in JP-A-51-77401, A developer composition comprising an anionic surfactant, an alkali agent and water;
No. 202, a developer composition comprising an aqueous solution containing benzyl alcohol, an anionic surfactant, and a water-soluble sulfite; a water-soluble solution described in JP-A-55-155355, which has a water solubility at room temperature. And a developer composition containing 10% by weight or less of an organic solvent, an alkali agent and water.

[0004] Each of these contains an organic substance such as an organic solvent and a surfactant in the developer composition. However, organic solvents are generally toxic and odorous, have a risk of fire, and have many disadvantages such as being subject to BOD regulations in waste liquids, and are expensive. Attempts to develop a photosensitive lithographic printing plate using a diazo resin with a developer composition substantially free of these organic solvents are described in JP-A-57-192952 and JP-A-58-27141. ing.

However, these developing solution compositions are used for developing a positive-working photosensitive lithographic printing plate containing an o-naphthoquinonediazide compound as a photosensitive compound, and these developing compositions containing substantially no organic solvent are used. When the photosensitive lithographic printing plate using the above-mentioned diazo resin is developed using the liquid composition, the diazo resin is essentially not soluble in alkaline water, and therefore development can be performed without forming a residual film. In addition, there is a problem that proper developability cannot be obtained, such as yellowing of the unexposed area.

On the other hand, in JP-A-2-189544, a diazo resin is prepared by using a co-condensed diazo resin containing an aromatic compound having a group selected from a carboxyl group, a hydroxy group, a sulfonic acid group and a sulfinic acid group. It is described that the compound can be made soluble in alkaline water to enable development with a developer containing substantially no organic solvent. However, when a photosensitive lithographic printing plate using these diazo resins is actually developed with a developer containing substantially no organic solvent, the image part is peeled from the support during printing or the printing durability in printing is low. There was a problem with.

[0007]

Accordingly, an object of the present invention is to subject a photosensitive lithographic printing plate having a photosensitive layer containing a diazo resin to development processing with an aqueous alkaline developing solution containing substantially no organic solvent to obtain a lithographic printing plate. In a method for producing a printing plate, it is to provide a method for producing a lithographic printing plate in which the image portion and the support are in close contact with each other and which has printing durability.

[0008]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to achieve the above-mentioned objects, the use of a mixed solvent containing both a high-boiling solvent and a low-boiling solvent as a coating solvent for a photosensitive layer has these objects. The present invention has been achieved by finding that the above is achieved. Although the reason why the adhesion is improved and the printing durability is improved is not clear, it seems that the dispersion state of the diazonium compound in the photosensitive layer is changed by coating and drying using two or more kinds of solvents. Be done.

That is, the present invention provides a photosensitive composition containing an aromatic diazonium compound having at least one selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group, and a phosphorus oxyacid group. Is 115
It is obtained by dissolving in a mixed solvent of at least two kinds of solvents selected from a high boiling point solvent having a boiling point of ℃ or higher and a low boiling point solvent having a boiling point of 95 ℃ or lower, coating this on a support and drying. After exposing the photosensitive lithographic printing plate
A method for producing a lithographic printing plate, which comprises developing with an aqueous alkaline developer having a pH of 12 or more at 0 ° C. and substantially containing no organic solvent.

Hereinafter, the present invention will be described in detail. The diazo resin contained in the photosensitive layer is a carboxyl group, a sulfonic acid group,
It is a cocondensate containing an aromatic compound having at least one group selected from the group consisting of a sulfonate group, a sulfinic acid group, and a sulfinic acid group, and an aromatic diazonium compound as a constituent unit.

The aromatic compound has, for example, at least one substituent selected from the group consisting of a carboxyl group, a sulfonate group, a sulfonate group, a sulfinate group, and a sulfinate group on the benzene ring or naphthalene ring. , Each substituent may be directly bonded to the aromatic ring,
It may be bonded via a linking group. Specific examples of the aromatic diazonium compound include 4-diazo-4'-methoxydiphenylamine salt, 4-diazo-4'-ethoxydiphenylamine salt, 4-diazo-3-methoxydiphenylamine salt and 4-diazo-diphenylamine salt. .

Specific examples of the aromatic compound include benzenesulfonic acid, sodium benzenesulfonate, 2-sodium m-benzenedisulfonic acid, p-toluenesulfonic acid, p-
Sodium toluenesulfonic acid, p-toluenesulfinic acid, sodium p-toluenesulfinate, sodium benzenesulfinate, aniline-2-sulfonic acid, 4-amino-m-toluenesulfonic acid, sodium 4-amino-m-toluenesulfonic acid 2,5-diaminobenzenesulfonic acid, 1-naphthalenesulfonic acid, 1-amino-2-naphthalenesulfonic acid, 5-amino-2-naphthalenesulfonic acid, 7-amino-1,3-naphthalenedisulfonic acid,
2-amino-1,5-naphthalenedisulfonic acid, 4-amino-1-naphthalenesulfonic acid sodium salt, 5-amino-
Sodium 1-naphthalenesulfonate, sodium 6-amino-1-naphthalenesulfonate, sodium 5-sulfoisophthalate, 2-sulfobenzoic acid, p-chlorobenzenesulfonic acid, benzoic acid, o-chlorobenzoic acid, m-chlorobenzoic acid Acid, p-chlorobenzoic acid, phthalic acid, terephthalic acid,
Diphenylacetic acid, phenoxyacetic acid, p-methoxyphenylacetic acid, p-methoxybenzoic acid, 2,4-dimethoxybenzoic acid, 2,4-dimethylbenzoic acid, p-phenoxybenzoic acid, 4-anilinobenzoic acid, 4- (m -Methoxyanilino) benzoic acid, 4- (p-methoxybenzoyl) benzoic acid, 4- (p-methylanilino) benzoic acid, 4-phenylsulfonylbenzoic acid, salicylic acid, 4-methylsalicylic acid, 6-methylsalicylic acid, 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, phloroglucin carboxylic acid, 2,4,5-trihydroxybenzoic acid,
4,6-dihydroxyphthalic acid, (2,4-dihydroxyphenyl) acetic acid, (2,6-dihydroxyphenyl)
Acetic acid, (3,4,5-trihydroxyphenyl) acetic acid,
p-hydroxymethylbenzoic acid, p-hydroxyethylbenzoic acid, 4- (p-hydroxyphenyl) methylbenzoic acid, 4- (o-hydroxybenzoyl) benzoic acid,
-(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 and the like can be mentioned. Of these, salicylic acid, p-hydroxybenzoic acid, and the like are particularly preferable. p-Methoxybenzoic acid, metachlorobenzoic acid, phenoxyacetic acid, benzenesulfonic acid, sodium benzenesulfonate, p-toluenesulfonic acid, sodium p-toluenesulfonate, p-toluenesulfinic acid, sodium p-toluenesulfinate, benzenesulfine Acid, sodium 5-sulfoisophthalate, 2-sulfobenzoic acid, 4-amino-m-toluenesulfonic acid, sodium 4-amino-m-toluenesulfonic acid, 1-naphthalenesulfonic acid, 2-
Amino-1,5-naphthalenedisulfonic acid, sodium 5-amino-1-naphthalenesulfonic acid, and p-chlorobenzenesulfonic acid.

The photosensitive diazo resin according to the present invention can be prepared by a known method, for example, Photographic Science and Engineering (Photo. Sci. Eng.) Volume 17,
Page 33 (1973), U.S. Pat. No. 2,063,631,
The aromatic compound, aromatic diazonium salt and aldehydes such as paraformaldehyde, acetaldehyde, benzaldehyde or ketones such as acetone and acetophenone in sulfuric acid, phosphoric acid or hydrochloric acid according to the method described in each specification of 2,679,498. It is obtained by polycondensation.

The charged molar ratio of the aromatic diazo compound to the aromatic compound is 1: 0.1 to 0.1: 1, preferably 0.1.
5: 1 to 1: 0.2, more preferably 1: 1 to 1: 0.2. In this case, the total of the aromatic diazo compound and the aromatic compound and the aldehydes or ketones are usually charged in a molar ratio of 0.6 to 1.5: 1, preferably 0.7 to 1.4: 1. A diazo resin is obtained by reacting at a low temperature for a short time, for example, for about 3 hours.

The diazo compound is contained in the photosensitive layer in an amount of 1 to 70% by weight, preferably 3 to 60% by weight. Next, the counter anion X ⁻ of the diazo resin will be described. X
^- is preferably an aliphatic or aromatic sulfonic acid anion, preferred examples among them, methanesulfonic acid, fluoroalkanesulfonic acids such as trifluoromethanesulfonic acid, lauryl sulfonic acid, dioctyl sulfosuccinic acid, dicyclohexyl sulfosuccinate, camphorsulfonic Acid, tolyloxy-3-propanesulfonic acid, nonylphenoxy-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-chlorobenzene Sulfonic 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, butylbenzenesulfonic acid, octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, butoxybenzenesulfonic acid, dodecyloxybenzenesulfonic acid, 2-methoxy-4-hydroxy-5-benzoylbenzenesulfonic acid , Isopropylnaphthalenesulfonic acid, butylnaphthalenesulfonic acid, hexylnaphthalenesulfonic acid, octylnaphthalenesulfonic acid, butoxynaphthalenesulfonic acid, dodecyloxynaphthalenesulfonic acid, dibutyl Lid sulfone acid, dioctyl naphthalene sulfonic acid, triisopropyl naphthalene sulfonic acid, tributyl naphthalene sulfonic 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-
It includes the anion of naphthoquinone-1-diazide-4-sulfonic acid or a mixture of these anions. Particularly preferred among these anions are anions of alkyl-substituted naphthalenesulfonic acids such as butylnaphthalenesulfonic acid, dibutylnaphthalenesulfonic acid, dioctylnaphthalenesulfonic acid, and tributylnaphthalenesulfonic acid.

The diazo resin used in the present invention can have any desired molecular weight by varying the molar ratio of each monomer and the condensation conditions, but it is effective for the intended purpose of the present invention. Molecular weight of about 400
~ 100,000, preferably about 800-5,000
Is appropriate. The above-mentioned photosensitive diazo resin is preferably used in combination with an alkali-soluble or swellable lipophilic polymer compound as a binder resin.

Examples of such lipophilic polymer compounds are:
Copolymers having a molecular weight of usually from 100,000 to 200,000, using the monomers shown in the following (1) to (14) as structural units, can be mentioned. (1) Acrylamides, methacrylamides, acrylates, methacrylates and hydroxystyrenes having an aromatic hydroxyl group, such as N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl) methacrylamide , O-, m-, p-
Hydroxystyrene, o-, m-, p-hydroxyphenyl-acrylate or methacrylate, (2) acrylic acid ester having an aliphatic hydroxyl group, and methacrylic acid ester such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, (3) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, and itaconic acid, (4) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, acrylic Octyl acid, acrylic acid-2
-(Substituted) alkyl acrylates such as -chloroethyl, glycidyl acrylate, N-dimethylaminoethyl acrylate, (5) methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, 4-
(Substituted) alkyl methacrylates such as hydroxybutyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate, (6) acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide,
N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl-
Acrylamide or methacrylamide such as N-phenylacrylamide, (7) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether, or other vinyl ethers, (8) vinyl acetate, Vinyl chloroacetate, vinyl butyrate, vinyl benzoate and other vinyl esters, (9) styrene, α-methyl styrene, chloromethyl styrene and other styrenes, (10) methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, Vinyl ketones such as phenyl vinyl ketone, (11) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene, (12) N-vinylpyrrolidone, N-vinyl Carbazole, 4-vinyl pyridine, acrylonitrile, methacrylonitrile, etc., (13) maleimide, N- acryloyl acrylamide,
Unsaturated imides such as N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide, (14) N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonyl) Methacrylic acid amides such as phenyl) methacrylamide, N- (p-amino) sulfonylphenylmethacrylamide, N- (1- (3-aminosulfonyl) naphthyl) methacrylamide, and N- (2-aminosulfonylethyl) methacrylamide. , And acrylamides having the same substituents as above, o-aminosulfonylphenyl methacrylate, m-aminosulfonylphenyl methacrylate,
p-aminosulfonylphenyl methacrylate, 1-
Methacrylic acid esters such as (3-aminosulfonylnaphthyl) methacrylate, and unsaturated sulfonamides such as acrylic acid esters having the same substituents as above.

Further, a monomer copolymerizable with the above-mentioned monomer may be copolymerized. Examples include, but are not limited to, those obtained by modifying a copolymer obtained by copolymerization of the above monomers with, for example, glycidyl methacrylate, glycidyl acrylate, or the like. More specifically, the above (1), (2), containing a monomer or the like listed in (14), a copolymer having a hydroxyl group or a sulfonamide group is preferable, having an aromatic hydroxyl group or a sulfonamide group Copolymers are more preferred.

The above copolymer preferably contains the unsaturated carboxylic acid listed in (3), and the preferable carboxylic acid value of the copolymer is 0 to 3 meq / g, and more preferably 0.5. ~ 2.5 meq / g. The preferred molecular weight of the copolymer is from 150,000 to 150,000. If necessary, a polyvinyl butyral resin, a polyurethane resin, a polyamide resin, an epoxy resin, a novolak resin, a natural resin, or the like may be added to the copolymer.

The lipophilic polymer compound used in the present invention is usually contained in the solid content of the photosensitive composition in an amount of 40 to 99% by weight, preferably 50 to 95% by weight. Further, the photosensitive diazo resin used in the present invention is generally contained in an amount of 1 to 60% by weight, preferably 3 to 40% by weight. The photosensitive composition of the present invention may further contain a dye. The dye is
It is used for the purpose of obtaining a visible image by exposure (exposure visible image) and a visible image after development.

As the dye, those which "change color tone" by reacting with free radicals or acids can be preferably used. Here, "change in color tone" includes both a change from colorless to a color tone and a change from color to colorless or a different color tone. Preferred dyes are those which form a salt with an acid to change the color tone. For example, Victoria Pure Blue BOH [Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Co., Ltd.], Patent Pure Blue [Sumitomo Mikuni Chemical Co., Ltd.], Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Violet, Methyl Green, erythrosine B, basic fuchsin, malachite green, oil red, m-cresol purple, rhodamine B, auramine, triphenylmethane series represented by 4-p-diethylaminophenyliminaphthoquinone, cyano-p-diethylaminophenylacetanilide, etc., Diphenylmethane-based, oxazine-based, xanthene-based, iminonaphthoquinone-based, azomethine-based or anthraquinone-based dyes that change from colored to colorless or different colored tones And the like as.

On the other hand, examples of the discoloring agent that changes from colorless to colored include leuco dyes and, for example, triphenylamine, diphenylamine, o-chloroaniline, 1,2,3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p. ′ -Bis-dimethylaminodiphenylamine, 1,2-dianilinoethylene, p, p ′,
p "-tris-dimethylaminotriphenylmethane,
p, p'-bis-dimethylaminodiphenylmethylimine, p, p ', p "-triamino-o-methyltriphenylmethane, p, p'-bis-dimethylaminodiphenyl-4-anilinonaphthylmethane, Primary or secondary arylamine dyes represented by p ', p "-triaminotriphenylmethane are exemplified.

Particularly preferably, triphenylmethane type and diphenylmethane type dyes are effectively used, more preferably triphenylmethane type dyes, and particularly Victoria Pure Blue BOH. The dye is preferably contained in the photosensitive composition in an amount of usually about 0.5 to about 10% by weight, more preferably about 1 to 5% by weight.

Various additives can be further added to the photosensitive composition of the present invention. For example, alkyl ethers (eg, ethyl cellulose,
Methylcellulose), fluorinated surfactants, nonionic surfactants (especially fluorinated surfactants are preferred), plasticizers for imparting flexibility and abrasion resistance to coating films (for example, butylphthalyl, polyethylene glycol, Tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers and polymers of acrylic acid or methacrylic acid, among which And tricresyl phosphate are particularly preferred), and a sensitizing agent for improving the sensitizing property of the image area (for example, JP-A-55-52).
No. 7, a half-esterified product of a styrene-maleic anhydride copolymer with an alcohol, a novolak resin such as pt-butylphenol-formaldehyde resin, a 50% fatty acid ester of p-hydroxystyrene, etc.), a stabilizer [for example, Phosphoric acid, phosphorous acid, organic acids (citric acid, oxalic acid, dipicolinic acid, benzenesulfonic acid, naphthalenesulfonic acid, sulfosalicylic acid, 4-methoxy-2-hydroxybenzophenone-5-sulfonic acid, tartaric acid, etc.), development Accelerators (eg, higher alcohols, acid anhydrides, etc.) are preferably used. The amount of these additives depends on the intended use and purpose,
Generally, it is 0.01 to 30% by weight based on the total solid content.

Such a photosensitive composition is coated on a suitable support to obtain a photosensitive lithographic printing plate. Such supports include paper, plastic (eg, polyethylene, polypropylene, polystyrene, etc.) laminated paper, aluminum (including aluminum alloys), zinc,
A metal plate such as copper, a plastic film such as cellulose diacetate, cellulose triacetate, cellulose propionate, polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyvinyl acetal, etc., and a metal as described above were laminated or vapor-deposited. Examples thereof include paper or plastic film, aluminum or chrome-plated steel plate, and among them, aluminum and aluminum-coated composite support are particularly preferable. IS aluminum is preferred as the aluminum support, but copper is 0.015
Aluminum with up to 0.03% is more preferred.

Further, it is desirable that the surface of the aluminum material is surface-treated for the purpose of enhancing water retention and improving adhesion with the photosensitive layer. For example, the following processing is performed. First, the aluminum plate is alkali, preferably 1 to 3
Etching is performed by immersing in an aqueous solution of 0% sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate or the like at a temperature of 20 to 80 ° C. for 5 seconds to 250 seconds. Aluminum may be added to the etching bath at about 1/5 of alkali.

Then, it is immersed in a 10-30% nitric acid or sulfuric acid aqueous solution at a temperature of 20-70 ° C. for 5 seconds-250 seconds,
Neutralization and smut removal are performed after alkali etching. After cleaning the surface of the aluminum plate, electrolytic surface roughening treatment is performed. The concentration of hydrochloric acid in the electrolytic solution used for electrolytic surface roughening treatment is preferably in the range of 0.01 to 3% by weight,
More preferably, it is 2.5 wt%.

Further, if necessary, this electrolytic solution contains a corrosion inhibitor (or a stable agent) such as nitrates, chlorides, monoamines, diamines, aldehydes, phosphoric acid, chromic acid, boric acid, oxalic acid and ammonium salts. Agent), a grain leveling agent, etc. can be added. The electrolyte may contain an appropriate amount (1 to 10 g / l) of aluminum ions.

The temperature of the electrolytic solution is usually 10 to 60 ° C.
As the alternating current used at this time, any of a rectangular wave, a trapezoidal wave, and a sine wave can be used as long as the positive and negative polarities are alternately exchanged. Phase alternating current can be used. The current density is preferably 5 to 100 A / dm ² , and the treatment is preferably performed for 5 to 300 seconds.

The surface roughness of the aluminum support in the present invention is adjusted to 0.2 to 0.8 μm by adjusting the amount of electricity. The grained aluminum plate is 10
It is preferable to remove smut adhering to the surface by hot sulfuric acid (40 to 60 ° C.) or dilute alkali (sodium hydroxide, etc.) to ˜50%. When removed with an alkali, it is subsequently neutralized by immersion in an acid (nitric acid or sulfuric acid) for washing.

After removing the surface smut, an anodic oxide film is provided. As the anodic oxidation method, a conventionally well-known method can be used, but sulfuric acid is used as the most useful electrolytic solution. Subsequently, phosphoric acid is also a useful electrolyte. Further, JP-A-55-28400
The mixed acid method of sulfuric acid and phosphoric acid disclosed in Japanese Patent Application Publication No. JP-A-2006-15764 is also useful.

In the sulfuric acid method, the treatment is usually carried out with a direct current, but it is also possible to use an alternating current. The concentration of sulfuric acid is 5
Used at 30%, 5-25 in a temperature range of 20-60 ° C
Electrolytic treatment is performed for 0 second to provide an oxide film of 1 to 10 g / m ^{2 on} the surface. This electrolyte preferably contains aluminum ions. Further, the current density at this time is preferably 1 to 20 A / dm ² . In the case of the phosphoric acid method, at a concentration of 5 to 50% and a temperature of 30 to 60 ° C.,
The treatment is performed at a current density of 1 to 15 A / dm ² for 300 seconds.

Further, if necessary, a surface treatment such as a pore-sealing treatment with an alkali silicate or hot water, or immersion in a water-soluble polymer compound or an aqueous solution of potassium fluorozirconate can be carried out. In order to provide the above-mentioned photosensitive composition on a support, a photosensitive diazo co-condensation resin, a lipophilic polymer compound, and, if necessary, various additives in predetermined amounts are added as a high boiling point boiling solvent and a low boiling point solvent. The coating solution of the photosensitive composition may be prepared by dissolving it in a mixed solvent of at least two kinds of solvents selected from boiling point solvents and coating it on a support, followed by drying. Here, the high boiling point solvent has a boiling point of 115
It is a substance having a temperature of ℃ or higher, and it is preferable to select from the following.

Methyl cellosolve, ethyl cellosolve, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, methyl cellosolve acetate, dimethylformamide, dimethylacetamide, cyclohexanone, methyl lactate, ethyl lactate, Dimethyl sulfoxide and the like.

The low boiling point solvent is a substance having a boiling point of 95 ° C. or lower, and it is desirable to select from the following. Methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, dimethoxyethane, tetrahydrofuran, ethylene dichloride and the like. The combination of the high boiling point solvent and the low boiling point solvent to be mixed may be any of the above, but as the low boiling point solvent, methanol or methyl ethyl ketone is more preferable.

If a high boiling point solvent and a low boiling point solvent are included, 3
One or more solvents may be combined. In this case, the solvent to be combined may include the following solvents having a boiling point of 95 to 115 ° C. in an amount of 20% by weight or less based on all the solvents. water,
Dioxane, n-propanol and the like. The mixing ratio of each solvent in the present invention is preferably 10 to 80% by weight for the low boiling point solvent and 10 to 80% by weight for the high boiling point solvent.

The solid content concentration of the photosensitive composition upon coating is preferably in the range of 1 to 50% by weight. In this case, the application amount of the photosensitive composition is approximately 0.2 to 10 g.
/ M ² (dry weight) may be set. It is preferable that there be a mat layer composed of protrusions provided independently of each other on the photosensitive layer.

The purpose of the matte layer is to improve the vacuum adhesion between the negative image film and the photosensitive lithographic printing plate in contact exposure, thereby shortening the vacuuming time and further crushing fine halftone dots during exposure due to poor adhesion. Is to prevent. Japanese Patent Application Laid-Open No. 55-129 describes a method for applying a mat layer.
No. 74, a method of heat-sealing powdered solid powder, and a method of spraying and drying polymer-containing water as described in JP-A-58-182636 are available, and any method may be used. It is desirable that the matte layer itself be soluble in an aqueous alkaline developer containing substantially no organic solvent or be removable by this.

As the solid powder in the method of heat-sealing the powdered solid powder, preferably, the first or second transition point of the substance or composition is higher than 40 ° C., and the substance is Alternatively, the first or second transition point of the composition is lower than the first transition point of the photosensitive layer. Specific examples include polyvinyl acetate, polyvinylidene chloride, polyethylene oxide, polyethylene glycol, polyacrylic acid, polyacrylamide,
Examples include polyacrylate, polystyrene, polystyrene derivatives, copolymers of these monomers, polyvinyl methyl ether, epoxy resin, phenol resin, polyamide, and polyvinyl butyral.

The diameter of the solid powder particles is appropriately in the range of about 0.5 to 40 μ, preferably in the range of 1 to 17 μ, and particularly preferably in the range of 1 to 8 μ. Powdering is performed in a known manner, such as JJ Sokol, RC Hendrickson, Plastic Engineering Handbook,
P.426, P.431 (1976) (JJ Sokol and R.
Fluidized bed as described in C. Hendrickson Plastic Eng. Handbook (1976))
A method using an air spray, a brush, a buff, or the like may be used in addition to an electrostatic spray, an electrostatic fluidized bed, or the like.

The amount of the solid powder adhered to the surface of the photosensitive lithographic printing plate is 1 to 1, solid powder per 1 mm ² of the photosensitive lithographic printing plate.
000 pieces are suitable, and 5 to 500 pieces are preferable. The solid powder that is powdered and adheres to the surface of the photosensitive lithographic printing plate is generally randomly distributed. In order to fix the solid powder to the surface of the photosensitive lithographic printing plate, the solid powder that has been powdered and adhered to the surface of the photosensitive lithographic printing plate is fixed to the surface by heat.

That is, heated air is blown to the powdered surface, or the surface of the solid powder is melted by passing the powdered photosensitive lithographic printing plate through a heated air chamber or a heated roll. Fix to the surface of the planographic printing plate. In the present invention, the aqueous alkaline developer containing substantially no organic solvent means that the organic solvent is not excessively contained from the viewpoints of hygiene, safety and the like, and is generally a developer composition. There is no problem if the content is 2% by weight or less. Preferred organic solvent content is 1% by weight
The following is a more preferred embodiment. As the alkali agent used in the developer according to the present invention, preferably potassium silicate, lithium silicate, sodium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, Potassium triphosphate, dibasic potassium phosphate, sodium carbonate, potassium carbonate and the like can be mentioned. Among these, a developer containing an alkali silicate such as potassium silicate, lithium silicate, or sodium silicate is most preferable because it has a good development gradation, and the composition of the alkali silicate is [SiO ₂ ] / [M] = 0.5-1.5 (here [Si
O ₂ ], [M] represent the molar concentration of SiO _{2 and} the molar concentration of total alkali metals, respectively. ) And SiO ₂ of 0.8-
A developer containing 8% by weight is preferably used. The H (25 ° C.) of the developer according to the present invention is 12 or more, preferably 12.5 to 14.

Further, in the developing solution, there is disclosed in JP-A-50-5132.
4, anionic surfactants and amphoteric surfactants, and nonionic surfactants as described in JP-A-59-75255 and JP-A-60-111246. To the photosensitive composition by containing at least one of the above-mentioned agents, or by including a polymer electrolyte as described in JP-A-55-95946 and JP-A-56-142528. It is possible to enhance wettability and further enhance gradation. The amount of the surfactant added is not particularly limited,
The concentration is preferably 0.003 to 3% by weight, particularly preferably 0.006 to 1% by weight. Further, potassium is 20 mol% in the total alkali metal as the alkali metal of the alkali silicate.
It is preferable that the content is not less than 90 mol%, and more preferable that the content of potassium is 100 mol% or more.
Is the case.

Further, if necessary, additives such as a defoaming agent and a water softener can be contained. Examples of the water softener include polyphosphates and aminopolycarboxylic acids. The optimum amount of such a water softener varies depending on the hardness of the hard water used and the amount used. However, if a general amount is used, 0.01 to 5% by weight in the developer at the time of use is used. , More preferably 0.01 to 0.5.
It is contained in the range of weight%.

As such an aqueous alkaline developer containing substantially no organic solvent, for example, JP-A-59-8424 is used.
No. 1, JP-A-57-192952, etc., and a developer composition used for developing a positive type lithographic printing plate after image exposure and then developing. Furthermore, in the development process of this type of photosensitive lithographic printing plate, the alkali aqueous solution is consumed depending on the processing amount, and the alkali concentration is reduced, or the alkali concentration is reduced by air due to long-time operation of the automatic developing solution. Although the processing capacity is reduced, the processing capacity may be restored by using a replenisher as described in JP-A-54-62004.

If necessary, desensitizing treatment after development treatment, washing with water, desensitizing treatment as it is, or treatment with an aqueous solution containing an acid, or desensitizing treatment after treatment with an aqueous solution containing an acid. May be given.

[0047]

In the present invention, since the mixed solvent of at least two kinds of solvents selected from the high boiling point solvent and the low boiling point solvent is used as the coating solvent for the photosensitive layer, the pH of 12
A lithographic printing plate having excellent printing durability in printing can be obtained even if it is developed using the above developing solution. Since the present invention uses an aqueous alkaline developer which does not substantially contain an organic solvent during the development process, it is a toxicity problem during work, a sanitary problem such as odor, a safety problem such as fire and gas explosion, and a waste liquid. It can be implemented at low cost without any problems such as pollution.

In the present invention, the negative lithographic printing plate can be developed using an aqueous alkaline developer which is known as a developer for positive lithographic printing plates. For this reason, when processing both a positive type lithographic printing plate and a negative type lithographic printing plate, a developer composition is prepared so as to be compatible with each, a developer composition is replaced, and two kinds of developer are used in advance. It is possible to save labor such as preparing the composition and the development processing apparatus, and the working efficiency, equipment cost, arrangement space, and the like are significantly improved.

Next, typical synthesis examples of the diazo resin according to the present invention will be shown. [Synthesis Example] Synthesis of diazo resin-1 3.5 g (0.025 mol) of p-hydroxybenzoic acid and 7.1 g (0.025 mol) of 4-diazodiphenylamine sulfate were dissolved in 90 g of concentrated sulfuric acid under cooling with water. did. To this reaction was slowly added 2.7 g of paraformaldehyde (0.09 mol). At this time, the reaction was added so that the reaction temperature did not exceed 10 ° C. Thereafter, stirring was continued under ice cooling for 2 hours. The reaction mixture was poured into 1 liter of ethanol under ice cooling, and the resulting precipitate was filtered. After washing with ethanol, the precipitate was dissolved in 200 ml of pure water, and to this solution was added a cold concentrated aqueous solution in which 10.5 g of zinc chloride was dissolved.
The resulting precipitate was filtered and washed with ethanol.
It was dissolved in 00 ml of pure water. To this solution was added a cold concentrated aqueous solution in which 28.7 g of sodium dibutylnaphthalenesulfonate was dissolved. The resulting precipitate was filtered off and washed with water, and then 30 ° C, 1
It was dried day and night to obtain diazo resin-1.

When the molecular weight of this diazo resin-1 was measured by GPC (gel permeation chromatography), the weight average molecular weight was about 1600. Synthesis of diazo resin-2 Diazo resin-2 was obtained in the same manner as in the synthesis of diazo resin-1, except that p-hydroxybenzoic acid was changed to 4.5 g of sodium benzenesulfonate in the synthesis of diazo resin-1.

When the molecular weight was measured by GPC, the weight average molecular weight was 1650. Synthesis of diazo resin-3 Diazo resin-3 was obtained in the same manner as in the synthesis of diazo resin-1 except that sodium dibutylnaphthalenesulfonate was replaced with ammonium hexafluorophosphate in the synthesis of diazo resin-1.

Next, synthetic examples of lipophilic polymer compounds will be shown. Synthesis of lipophilic polymer compound-1 N- (4-hydroxyphenyl) methacrylamide 53
g, acrylonitrile 16 g, methyl methacrylate 30
g, 8 g of ethyl acrylate, 2 g of methacrylic acid and 3.3 g of azobisisobutyronitrile were dissolved in 220 ml of a 1: 1 mixed solution of acetone-ethanol, and after nitrogen substitution, the mixture was heated at 60 ° C. for 8 hours.

After the reaction was completed, the reaction solution was poured into 5 liters of water with stirring, and the resulting white precipitate was collected by filtration and dried to obtain 90 g of polymer compound-1. This lipophilic polymer compound-1 is represented by G
When the molecular weight was measured by PC, the weight average molecular weight was 29,000. Synthesis of lipophilic polymer compound-2 N- (p-aminosulfonylphenyl) methacrylamide 4.57 g (0.0192 mol), acrylonitrile 2.55
g (0.0480 mol), methacrylic acid 1.66 g (0.019 g)
2 mol), 18.40 g (0.1136 g) of benzyl acrylate
mol), 0.41 g of α, α'-azobisisobutyronitrile
And 25 g of N, N-dimethylformamide,
Put into a 100 ml three-necked flask equipped with a cooling tube,
While stirring for 5 hours. This reaction mixture was poured into 2 liters of water with stirring, stirred for 30 minutes, filtered and dried to obtain 19 g of polymer compound-2.
The weight average molecular weight (polystyrene standard) of this polymer compound-2 measured by GPC was 18,000. Example 1 A JIS A1050 aluminum plate containing 0.02% copper, 0.01% titanium, 0.30% iron and 0.1% silicon was etched with a 5% sodium hydroxide aqueous solution at 50 ° C. for 10 seconds. And then neutralized in a 30% nitric acid bath at 25 ° C for 30 seconds,
This was electrolytically etched in a 2% hydrochloric acid bath at a current density of 20 A / dm ² at 25 ° C., then neutralized with a 1% aqueous sodium hydroxide solution at 20 ° C. for 30 seconds, washed with water, and then in a 15% sulfuric acid bath. Anodization was performed for 2 minutes at 30 ° C. and 1.5 A / dm ² . Next, a 1% sodium metasilicate aqueous solution 85 ° C., 30
The plate was sealed for 2 seconds, washed with water and dried to obtain an aluminum plate for lithographic printing.

The film weight after drying Photosensitive Solution-1 having the following composition on this aluminum plate was dried using a Whiler coater.
It was applied so as to be 2.4 g / m ² . Drying in this case was performed at 100 ° C. for 1 minute. Photosensitizer-1 Lipophilic polymer-15.0 g Diazo resin-1 0.6 g Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.1 g Julimer AC-10L (Nippon Pure Chemical Co., Ltd.) 0.3 g Methyl Cellosolve 50 ml Methanol 30 ml Methyl ethyl ketone 20 ml A solid powder consisting of the following resin, which was crushed with a ball mill and classified with a classifier (Zigzag classifier manufactured by Albime Co.) on the photosensitive layer, was powdered with a spray gun. Then, it was fixed by exposing it to an air bath at 150 ° C. for 5 seconds. 1
The amount of powder per mm ² was 55. Solid powder resin: styrene / methyl acrylate / acrylic acid (2: 1: 1) copolymer powder having a particle size of 0.5 to 10 μm The obtained photosensitive lithographic printing plate was used as a negative transparent original image and a step wedge (optical). The density was increased stepwise by 0.150), and exposed for 5 seconds from a distance of 1 m with a 5 KW metal halide lamp.

Further, development processing was performed under the following conditions.
In other words, Fuji Photo Film Co., Ltd.'s automatic machine Stublon 9
00D, the following developer 1 and finisher FN-2 manufactured by Fuji Photo Film Co., Ltd. were charged, and the developer temperature was 3
The treatment was performed at 0 ° C. to obtain a lithographic printing plate. Composition of developer-1 1K potassium silicate 60g potassium hydroxide 12g boron-based surfactant (Emalbon T-20) 0.1g chelating agent (EDTA) 0.1g silicon-based defoamer (TSA-731 manufactured by Toshiba) 1 g Cobalt acetate 0.3 g Water 600 g Developer-1 had a pH of 13.1.

The lithographic printing plate thus obtained was used to print on high-quality paper with a commercially available ink using a SOR printer manufactured by Heidelberg. Table 1 shows the obtained results. Example 2 The procedure of Example 1 was repeated, except that the diazo resin-1 in the photosensitive liquid-1 in Example 1 was changed to the diazo resin-2. Example 3 The procedure of Example 1 was repeated, except that the diazo resin-1 in the photosensitive solution-1 in Example 1 was changed to the diazo resin-3. Example 4 The same procedure was performed as in Example 1 except that the lipophilic polymer compound-1 in the photosensitive liquid-1 in Example 1 was replaced with the lipophilic polymer compound-2 and the solvent was replaced with 40 ml of methyl cellosolve and 60 ml of methanol. Example 5 In the photosensitive liquid-1 in Example 1, the solvent was 1-methoxy-2-propanol 40 ml and methanol 40 ml.
The same procedure as in Example 1 was repeated except that water was changed to 5 ml. Comparative Example 1 The same procedure as in Example 1 was carried out except that methylcellosolve 70 ml was used as the solvent in the photosensitive liquid-1 in Example 1.

[0057] As can be seen from Table 1, according to the present invention, a lithographic printing plate excellent in printing durability can be obtained even if the development is carried out using a developer containing substantially no organic solvent.

Claims (2)

(57) [Claims] 1. A photosensitive composition containing an aromatic diazonium compound having at least one selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfinic acid group and an oxygen acid group of phosphorus, and having a boiling point of 115 ° C. It was obtained by dissolving in a mixed solvent of at least two kinds of solvents selected from the above high boiling point solvent and low boiling point solvent having a boiling point of 95 ° C. or less, coating this on a support, and drying. After exposing the photosensitive lithographic printing plate imagewise, the pH at 25 ° C
Is 12 or more and is developed with an aqueous alkaline developer containing substantially no organic solvent, and a method for producing a lithographic printing plate. 2. The method for producing a lithographic printing plate as claimed in claim 1, wherein the low boiling point solvent is methanol or methyl ethyl ketone.