JPH0545867A - Plate making method for dampening waterless photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To improve the sensitivity and image reproducibility of the dampening waterless photosensitive planographic printing plate having a photosensitive layer contg. a polymer having a silver halide, arom. amine and arom. hydroxyl group by subjecting this printing plate to development processing with an aq. alkaline soln. CONSTITUTION:This dampening waterless photosensitive planographic printing plate which has the photosensitive layer and a silicone rubber layer in this order on a base and has the photosensitive layer contg. the polymer having the silver halide, arom. amine and arom. hydroxyl group is subjected to the development processing with the aq. alkaline soln. The silver halide to be used for the photosensitive layer of the waterless plate is the water-insoluble and org. solvent-insoluble photosensitive silver halide. A silver chloride, silver bromide, silver iodide, silver chlorobromide, silver iodobromide, silver chlorobromoiodide, etc., are included as such silver salt, which can be formed by the reaction of silver nitrate and alkaline metal halide or ammonium halide. An aniline compd. is more particularly preferably used as the arom. amine used for the photosensitive layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of making a photosensitive lithographic printing plate which does not require a dampening water, and more specifically, it makes a photosensitive lithographic printing plate which does not require a dampening water and which provides high sensitivity and excellent image reproducibility. Regarding the method.

[0002]

2. Description of the Related Art As a photosensitive layer of a photosensitive lithographic printing plate which does not require fountain solution (hereinafter also referred to as waterless lithographic plate), a photopolymerizable composition is disclosed in JP-A 1-118843 and JP-A-49-7005. Discloses a photocrosslinking composition, and JP-A-49-8306 discloses a diazo composition.

However, in the waterless planographic printing plate of the photosensitive layer having such a constitution, the sensitivity was insufficient especially for a low-power laser when recording with a visible light laser. For this reason, there is no choice but to use a large-sized, high-power laser device, which causes problems in terms of cost and installation space.

Further, it cannot be said that the image reproducibility, especially the dot reproducibility, is sufficiently satisfactory, and further improvement is desired.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a photosensitive lithographic printing method which does not require a fountain solution and which provides high sensitivity to the extent that it can be recorded by a low-power visible light laser and excellent image reproducibility (halftone dot reproducibility). It is an object to provide a plate making method.

[0006]

The inventors of the present invention have conducted extensive studies in view of the above objects, and as a result, the above objects of the present invention include a photosensitive layer and a silicone rubber layer on a support in this order. It was found that the photosensitive layer can be achieved by a plate-making method in which a fountain solution-free photosensitive lithographic printing plate containing a silver halide, an aromatic amine and a polymer having an aromatic hydroxyl group is subjected to a developing treatment with an aqueous alkaline solution.

The present invention will be described in detail below.

The silver halide used in the light-sensitive lithographic layer of the present invention is a water-insoluble, organic solvent-insoluble photosensitive silver halide. Examples of such silver salts are silver chloride, silver bromide, and iodo. Silver halide, silver chlorobromide, silver iodobromide, silver chlorobromoiodide and the like are included. And these can be formed by the reaction of silver nitrate with an alkali metal halide or an ammonium halide.

In the present invention, the content of the silver halide in the photosensitive layer is 0.1 to 30% by weight, preferably 1 to 20% by weight based on the total solid content of the photosensitive layer.

An aniline-based compound is particularly preferably used as the aromatic amine used in the photosensitive layer of the present invention.
Specific examples include the following compounds.

That is, aniline, 4-chloro-2-nitroaniline, 6-chloro-2-cyano-4-nitroaniline, 6-bromo-2-cyano-4-nitroaniline, 5-chloro-2-phenoxyaniline. , 4-amino-2-methylaniline, 2-methyl-4-nitroaniline, 2,5-diethoxyaniline, 2,4,6-trichloroaniline, 4-amino-2,6-dichloroaniline, 2,5 -Dichloroaniline, 2-chloroaniline,
2-chloro-5-cyanoaniline, 2,6-dichloro-
4-nitroaniline, 4-amino-2-nitroaniline, 2-amino-4-nitroaniline, 2-nitro-4
-Sodium sulfonate aniline, 2-cyano-4-nitroaniline, 2-amino-4-chloroaniline, 3-
Chloroaniline, 2,4,5-trichloroaniline, 2
-Methoxy-5-sulfamoylaniline, 3-N, N
-Dimethylamino-4-methoxyaniline, 2,5-dimethoxyaniline, 2-methoxy-5-N, N-diethylsulfamoylaniline, 2-methoxy-5-benzylsulfonylaniline, 2,5-diethoxy-4- Nitroaniline, 2,5-dimethoxy-4-nitroaniline, 4-methoxy-2-nitroaniline, 2-methoxy-5-nitroaniline, 2-methoxy-4-nitroaniline, 2,5-dimethoxy-4'- Nitro-4-phenylazoaniline, 2-chloro-5-trifluoromethylaniline, 4-chloro-2-methylaniline, 5-chloro-2-methylaniline, 2,2'-dimethyl-4-phenylazoaniline, 5-chloro-2,4-dimethoxy-aniline, 5-chloro-2-methoxyaniline, 3-
Carboxyaniline, 4-carboxy-phenylhydrazine, 5-carboxy-2-chloroaniline, 5-carboxy-2-methoxyaniline, 4-benzoylamino-2,5-diethoxyaniline, 2-methoxy-5-N
-Phenylcarbamoylaniline, 4-benzoylamino-2-methoxy-5-methylaniline, 5-carbamoyl-2-methoxyaniline, 3'-chloro-2-methoxy-2'-methyl-5-N-phenylcarbamoylaniline, 2'-chloro-2-methoxy-5-N-phenylcarbamoylaniline, 4-acetylamino-2-carboxyaniline, 4-N-phenylcarbamoylaniline, 5-carbamoyl-2-chloroaniline, 4-carbamoylaniline, 5 -Carbamoyl-2-methylaniline, 4-benzoylamino-2,5-dimethoxyaniline, 4-methoxyaniline, 4-N, N-diethyl-2,5-dimethoxyaniline, 4-N, N-diethyl-2- Methoxyaniline, 4-methylaniline, 4-
N, N-dibenzoyl-3,5-dichloroaniline, 4
-N, N-dimethylaniline, 4-nitroaniline, 4
-N, N-diethylaniline, 4'-methoxy-2,5
-Diethoxy-4-benzoylaminoaniline, 4-N
-Benzyl-N-methyl-2,5-dimethoxyaniline, 4'-methyl-2,5-diethoxy-phenylthioaniline, 4'-methoxy-2,5-diethoxy-phenylthioaniline, 4'-methoxy-2 , 5-dimethoxy-phenylaniline, 2,5-dimethoxyaniline,
4-N, N-dipropylaniline, 4-N-hydroxyethyl-N-ethylaniline, 4-N, N-diethyl-
3-chloroaniline, 4-N-benzyl-N-methyl-
2,5-dimethoxyaniline and the following compounds may be mentioned.

[0012]

[Chemical 1]

In the present invention, the aromatic amine is contained in the photosensitive composition in an amount of preferably 5 to 50% by weight, more preferably
It is contained in an amount of 10 to 30% by weight.

Further, the polymer having an aromatic hydroxyl group in the present invention is preferably a polymer obtained by condensing a phenol with an aldehyde or a ketone, particularly in the presence of an acidic catalyst. Examples of the phenols include phenol and o
-Cresol, m-cresol, p-cresol, 3,
Monohydric phenols such as 5-xylenol, carvacrol, thymol, p-alkyl group (1 to 8 carbon atoms) substituted phenols, divalent phenols such as catechol, resorcinol and hydroquinone, trivalent phenols such as pyrogallol and phloroglucin Is mentioned. Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde, furfural and the like. Of these, formaldehyde and benzaldehyde are preferable. Further, examples of the above-mentioned ketone include acetone and methyl ethyl ketone, and acetone is preferable.

Examples of the acidic catalyst used in the synthesis of the polycondensation resin include inorganic acids and organic acids such as hydrochloric acid, oxalic acid, sulfuric acid, phosphoric acid, phosphorus oxychloride, etc., and the above phenols and aldehydes or ketones. The compounding ratio with is preferably 0.7 to 1.0 part by mole of aldehyde or ketone with respect to 1 part by mole of phenols. However, when an aldehyde or a ketone is used as the reaction solvent, the compounding ratio is not limited to the above. Examples of the reaction solvent include alcohols such as methanol and ethanol, acetone, water, tetrahydrofuran and the like. The reaction product has a predetermined temperature (-5 to 120 ° C),
After the reaction for a predetermined time (3 to 48 hours), it can be obtained by heating under reduced pressure, washing with water and dehydration, or by water precipitation.

Specific examples of the polycondensation resin include phenol / formaldehyde resin, m-cresol / formaldehyde resin, m- and p-mixed cresol / formaldehyde resin, phenol / cresol / formaldehyde resin, phenol / benzaldehyde resin, Cresol / benzaldehyde resin, resorcin / benzaldehyde resin, resorcin / formaldehyde resin,
Pyrogallol / formaldehyde resin, Pyrogallol /
Acetone resin, pyrogallol benzaldehyde resin,
Hydroquinone / formaldehyde resin, catechol /
Formaldehyde resin etc. are mentioned. Of these, preferred are pyrogallol-formaldehyde resin, resorcinol-benzaldehyde resin and pyrogallol-acetone resin. Most preferred is pyrogallol-acetone resin.

The polycondensation resin has a molecular weight (polystyrene standard) of 2.0 × 10 ^{3 to} 2.0 × 10 ⁴ in terms of weight average molecular weight Mw and 7.0 × 10 ^{2 to} 5.0 × 10 ^{3 in} terms of number average molecular weight Mn. Is more preferable, and Mw is more preferably 3.0 × 10 ^{3 to} 6.0.
It is a value of × 10 ³ and Mn is a value within the range of 7.7 × 10 ^{2 to} 1.2 × 10 ³ .

The molecular weight of the resin is measured by GPC (gel permeation chromatography method).
The number average molecular weight Mn and the weight average molecular weight Mw are calculated by Morio Tsuge, Tatsuya Miyabayashi and Masayuki Tanaka, "Journal of the Chemical Society of Japan," pages 800-8.
According to the method described on page 05 (1972), the peaks in the oligomer region are leveled (the peaks and valleys of the peaks are connected).

The polymer having an aromatic hydroxyl group of the present invention also includes a vinyl copolymer having a structural unit having an aromatic hydroxyl group in the molecular structure. The copolymer is a polymer formed by the cleavage of a carbon-carbon double bond, and comprises at least one structural unit represented by each of the following general formulas [I] to [V]. Copolymers containing are preferred.

[0020]

[Chemical 2] In the formula, R ₁ and R ₂ are each a hydrogen atom, an alkyl group,
Alternatively, it represents a carboxyl group, preferably a hydrogen atom. R ₃ represents a hydrogen atom, a halogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group such as a methyl group or an ethyl group. R ₄ represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and preferably an aryl group. A represents an alkylene group which may have a substituent which connects a nitrogen atom or an oxygen atom and an aromatic carbon atom, m represents an integer of 0 to 10, and B represents phenylene which may have a substituent. Represents a naphthylene group which may have a group or a substituent.

In the above copolymer, the above-mentioned general formula [I]
~ As a monomer unit that can be used in combination with at least one structural unit represented by each of [V],
For example, ethylenically unsaturated olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene, for example, styrenes such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, and acrylics such as acrylic acid and methacrylic acid. Unsaturated aliphatic dicarboxylic acids such as itaconic acid, maleic acid and maleic anhydride, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate, Phenyl acrylate, α-methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, esters of α-methylene aliphatic monocarboxylic acid such as ethyl ethacrylate, for example, acrylonitrile, nitriles such as methacrylonitrile, for example, Amides such as acrylamide, such as acrylic anilide, p- chloro acrylic anilide,
Anilides such as m-nitroacrylanilide and m-methoxyacrylanilide, for example vinyl acetates such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, β-chloroethyl. Vinyl ethers such as vinyl ether, vinyl chloride,
Vinylidene chloride, vinylidene cyanide, ethylene such as 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxycarbonylethylene, and 1-methyl-1-nitroethylene. There are vinyl monomers such as derivatives, for example, N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidene and N-vinylpyrrolidone. These vinyl monomers have a structure in which unsaturated double bonds are cleaved and are present in the polymer compound.

Among the above-mentioned monomers, those represented by the general formulas [I] to
As a compound used in combination with at least one structural unit represented by [V], (meth) acrylic acids, esters of aliphatic monocarboxylic acids, and nitriles are preferable because they show comprehensively excellent performance. More preferred are methacrylic acid, methyl methacrylate, acrylonitrile, ethyl acrylate and the like.

These monomers may be bound to the above-mentioned copolymer in either a block or random state.

In the above-mentioned copolymer, the general formula [I]
The content of the structural unit represented by each of [V] is 5 to
70 mol% is preferable, and 10 to 40 mol% is particularly preferable.
The above copolymers may be used alone in one of the above combinations, or may be used in combination of two or more in the photosensitive composition.

In the present invention, the above-mentioned polymer having an aromatic hydroxyl group is contained in the photosensitive layer in an amount of preferably 10 to 90% by weight, more preferably 20 to 60% by weight.

The above-mentioned polymer having an aromatic hydroxyl group used in the photosensitive composition of the present invention is prepared by a generally known radical polymerization method or the like, for example, an initiator (0.1 to 4.0) such as azobisisobutyronitrile or benzoyl peroxide. Mol%) and is easily synthesized by a solution polymerization method.

The molecular weight of the polymer is generally GP.
The weight average molecular weight is preferably 5.00 × 10 ^{3 to} 2.00 × 10 ^5, more preferably 1.00 × 10 ^{4 to} 8.00 × 10 ⁴ , and particularly preferably 1.50 × 10 ^{5 as} a standard polystyrene comparative molecular weight by method C.
^{4 to} 5.90 × 10 ⁴ , and it is preferable that the molecular weight is relatively low.

On the other hand, the molecular weight dispersion ratio (representing the value Mw / Mn obtained by removing the weight average molecular weight Mw by the number average molecular weight Mn. Hereinafter referred to as the dispersion ratio) is preferably 5.0 or less, more preferably 4.0 or less.

The above-mentioned polymer having an aromatic hydroxyl group used in the present invention can satisfactorily disperse the silver halide even in a non-aqueous solvent. These hydrophilic resins can be used together. As such a hydrophilic resin, JP-A-57-176033 is known.
No. 5 of the publication or No. 2 of JP-A-57-211146
The one described on page 4 is used.

In addition to the materials described above, the photosensitive layer may further contain dyes or pigments, or a visible light exposure agent, a coatability improver, etc., if necessary, to improve the development visibleness or the exposure visible image. And coating properties can be improved.

Examples of the dye include Victoria Pure Blue BOH, Oil Blue # 603, Oil Pink # 31.
2, patent pure blue, crystal violet,
Leuco Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Green, Erythrosin B, Basic Fuchsin, Malachite Green, Leucomalachite Green, m-Cresol Purple, Cresol Red, Xylenol Blue, Rhodamine B, Auramine, 4-p-Diethylaminophenyliminonaphthoquinone , Triphenylmethane type, diphenylmethane type, oxazine type, xanthene type, iminonaphthoquinone type, azomethine type or anthraquinone type dyes such as cyano-p-diethylaminophenylacetanilide. The above dye is usually contained in the photosensitive layer in an amount of about 0.01.
To about 10% by weight, preferably about 0.05-8% by weight.

As the coating property improver, alkyl ethers (eg ethyl cellulose, methyl cellulose), fluorine-based surfactants and nonionic surfactants (eg Pluronic L-64 (manufactured by Asahi Denka Co.)) FC-430 are used.
(Made by Sumitomo 3M) and the like.

Examples of the visible light exposure agent include triazine compounds and oxadiazole compounds.

In the present invention, the film thickness of the photosensitive layer is 0.1 mg / d.
m ^{2 to} 30 mg / dm ² is preferable, and 0.5 mg / dm ^{2 to} 10 mg / dm ² is more preferable.

In the present invention, a silicone rubber layer is provided on the photosensitive layer. As the silicone rubber used in the silicone rubber layer, linear or cross-linked organopolysiloxane is preferable. The organopolysiloxane has a molecular weight of usually 1,000 to several hundreds of thousands, and is appropriately crosslinked in the form of a liquid, wax or dough at room temperature. The organopolysiloxane is classified into a condensation type and an addition type depending on the method of crosslinking.

The condensation type is one in which crosslinking is carried out by a condensation reaction, and water, alcohol, organic acid, etc. are released by the reaction. A particularly useful condensation type silicone rubber is a mixture of a linear organopolysiloxane having hydroxyl groups at both ends or a part of the main chain and a silicone crosslinking agent,
Examples thereof include those obtained by reacting a hydroxyl group with a silicone cross-linking agent. In both cases, it is advantageous to add a condensation catalyst in terms of the cross-linking speed.

The above organopolysiloxane has the following repeating units in the main chain.

[0038]

[Chemical 3] In the formula, R ₁ and R ₂ are each a cyano group, a halogen atom, an alkyl which may have a substituent such as a hydroxyl group, an aryl,
It is alkenyl or a combination thereof, and a methyl group, a phenyl group, a vinyl group and a trifluoropropyl group are preferable, and a methyl group is particularly preferable.

As the above silicone crosslinking agent,

[0040]

[Chemical 4] Or a condensation type silicone having a functional group represented by -OH (wherein R and R'are each an alkyl group) such as deacetic acid type, deoxime type, dealcohol type, deamino type and dehydration type A cross-linking agent can be used. Examples of such cross-linking agents include tetraacetoxysilane, methyltriacetoxysilane, ethyltriacetoxysilane, phenyltriacetoxysilane, dimethyldiacetoxysilane, diethyldiacetoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, dimethyl. Examples thereof include dimethoxysilane, vinyltrimethoxysilane, methyltris (acetoneoxime) silane, methyltri (N-methyl, N-acetylamino) silane, vinyltri (methylethylketoxime) silane, methyltri (methylethylketoxime) silane and oligomers thereof. ..

The amount of each of these crosslinking agents is preferably 0.5 to 30 parts by weight based on 100 parts by weight of the organopolysiloxane.

Examples of the condensation catalyst include organic carboxylic acids, titanic acid esters, naphthenic acids and the like.

The addition type means that an unsaturated group in the main body, for example, a vinyl group (-CH = CH ₂ ) is crosslinked by addition of the (Si-H) group in the crosslinking agent. Specific examples include vinyl group-containing organopolysiloxanes, hydrogenated organopolysiloxanes, and the like mixed with a platinum catalyst (for example, chloroplatinic acid). The organopolysiloxane has a repeating unit similar to the condensation type in the main chain.

In the silicone rubber layer of the present invention, it is possible to use either or both of condensation type and addition type silicone rubbers. It is also possible to use a condensed and addition type one having a hydroxyl group, an unsaturated group and the like in one organopolysiloxane. Among the commercially available products available as the silicone rubber according to the present invention, preferred examples include:
Shin-Etsu Co., Ltd. "KS-705F", "KE-41", "KE
-42 "," KE-44 ", Toshiba Silicone" YE55 "
05 "," YF3057 ", Toray Silicone" SH-78 "
1 "," PRX-305 "," SH-237 "and other condensation type silicone rubbers, and Shin-Etsu's" KS-837 "," KE-1 "
Addition type silicone rubbers such as "03", "KE-106", "KE-1300", Toshiba Silicone "TSE-3032", "RTU-B", Toray Silicone "SH-9555", etc. Be done.

Further, for the purpose of improving the strength of the silicone rubber, an inorganic filler such as silica, titanium oxide or aluminum oxide may be added, and silica is particularly preferably used. As such a filler, those having an average particle size of 500 nm or less are preferable from the viewpoint of dispersibility or dispersion stability.

In the present invention, the thickness of the silicone rubber layer is preferably as thin as possible from the viewpoint of image quality and developability. On the contrary, from the viewpoints of printing durability and stains on the print, it is necessary to have a certain thickness. preferably is ^{3mg / dm 2 ~50mg / dm 2} ,
5mg / dm ² ~30mg / dm ² is more preferable.

In the present invention, an adhesive layer made of, for example, an epoxy resin may be provided between the photosensitive layer and the silicone rubber layer, and various reactive crosslinking agents, silane coupling agents, etc. may be added to the adhesive layer. It may be contained, and the film thickness of the adhesive layer is preferably 0.02 mg / dm ^{2 to 1} mg / dm ² .

In the present invention, a primer layer is preferably provided between the support and the photosensitive layer. As the primer layer used in the present invention, any of various known primer layers can be applied. For example, epoxy resin, polyurethane resin and the like which are heat-cured using a suitable curing agent, etc. JP-B-61-54219. The primer layer described in JP-A-60-229031 and the like, such as the primer layer described in JP-A No. 60-90, or the one obtained by photo-curing a layer formed of a photo-dimer type curable resin, and the like can be used. A primer layer obtained by photo-curing a layer mainly composed of a diazo resin and a hydroxyl group-containing polymer is also preferably used, and such a diazo resin and a hydroxyl group-containing polymer are respectively the diazo resin and the hydroxyl group-containing polymer used in the above-mentioned photosensitive layer. Similar ones are used.

The proportion of the diazo resin in the primer layer in the present invention is usually 1 to 90% by weight, preferably 3 to 60% by weight. The proportion of the hydroxyl group-containing polymer in the primer layer is usually 10 to 99% by weight, preferably 40 to 97% by weight.

Further, a primer layer obtained by photocuring a layer made of a photopolymerizable composition made of an addition-polymerizable unsaturated compound is also preferably used.

The composition preferably comprises (a) a vinyl monomer having at least two terminal vinyl groups, (b)
It comprises a photopolymerization initiator and a polymer compound (c) as a binder.

As the vinyl monomer of the above component (a),
Those described in JP-B Nos. 35-5093, 35-14719, and 44-28727 are used.

As the photopolymerization initiator of the above component (b),
The compound represented by the following general formula [VII] can be used.

[0054]

[Chemical 5][In the formula, R¹, R²And R³Are hydrogen atom,
R group or an alkoxy group, R^FourIs a hydrogen atom, alk
Group or phenyl group. X is PF₆Or BF _FourShows
Y represents -NH-, -S- or -O-. ]

Other types of compounds can also be used. For example, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds as described in Chapter 5 of "Light Sensitive Systems" by J. Kosar,
Examples include azo and diazo compounds, halogen compounds, and photoreducible dyes. More specifically, it is disclosed in British Patent 1,459,563.

Further, as the binder of the component (c),
Various known polymers can be used. Details of specific binders are described in US Pat. No. 4,072,527.

In the present invention, in addition to the above-mentioned components, the primer layer may further contain, if necessary, a filler such as titanium oxide or zinc oxide or an antihalation agent, a coloring agent such as a dye or a pigment, a coatability improving agent, and a plasticizer. Agents, stabilizers, sensitizers, etc.
You may contain in the range which does not exceed 50 weight%.

As the dye and the coatability improving agent, the same ones as those contained in the photosensitive layer are used.

Examples of the plasticizer for imparting flexibility and abrasion resistance to the coating film include butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate,
Dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrafurfuryl oleate,
Examples thereof include oligomers of acrylic acid or methacrylic acid.

Various additives having a hydrophobic group such as p-octylphenol / formalin novolac resin, pt-butylphenol / formalin novolac resin, pt-
Modified novolak resins such as butylphenol / benzaldehyde resin and rosin modified novolac resin, and the o-naphthoquinone diazide sulfonic acid ester (the esterification rate of OH group is 20 to 70 mol%) of these modified novolac resins does not exceed 20% by weight. It can be added and used in the range.

Each of the above components is dissolved in a suitable organic solvent,
After coating and drying on the support, the primer layer is formed by exposing to light and completely decomposing the diazo resin or proceeding polymerization and curing.

The thickness of the primer layer is 1 mg / dm ^{2 to} 600 mg /
dm ² is preferred, and more preferably 3 mg / dm ²
It is 300 mg / dm ² .

Further, in the waterless planographic printing plate of the present invention, a protective layer may be provided on the silicone rubber layer, and as a method for providing the protective layer, a polypropylene film described in JP-B-61-614 is laminated. A method and a method of applying a high molecular polymer described in JP-A No. 61-27545 are known.

The support used in the present invention has flexibility so that it can be set in an ordinary lithographic printing machine,
Any material can be used as long as it can withstand the load applied at the time of printing, and the layer structure is not particularly limited. For example, papers such as coated papers, metal plates such as aluminum plates, or plastic films such as polyethylene terephthalate can be cited as examples.

The support used in the present invention is preferably an aluminum plate or an aluminum foil and another composite material, and an aluminum plate is particularly preferable from the viewpoint of printing durability.

The thickness of the support is preferably 0.1 to 0.3 mm.

The photosensitive lithographic printing plate unnecessary for fountain solution prepared as described above was imagewise exposed, and then developed with a developing solution to dissolve the photosensitive layer, and the silicone rubber layer thereon was removed to obtain an image of the primer layer. Exposed as a portion, and a fountain solution-free lithographic printing plate is formed.

In this case, it is preferable to dye the image area with a cationic dye such as crystal violet, Victoria Blue BOH, and Astrazonelet during or after development.

The light source used for the exposure may be any general-purpose light source including ultraviolet rays of 180 nm or more and visible light, but carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes, etc. are particularly preferable. ..

In the present invention, an aqueous alkaline solution is used as the developing solution.
A developer containing an alkali agent in an amount of at least 50% by weight, preferably 50% to 98% by weight, and optionally an organic solvent and a surfactant can be mentioned.

Examples of the organic solvent contained in the aqueous alkaline developer include aliphatic hydrocarbons (hexane, heptane, "Isopar EHG" (trade name of aliphatic hydrocarbons manufactured by Esso Kagaku). Or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene etc.), or halogenated hydrocarbons (triclene etc.), alcohols (methanol, ethanol, 1-butoxy-2-propanol, etc.)
3-methyl-3-methoxybutanol, β-anilinoethanol, benzyl alcohol, etc.), ethers (methylcellosolve, ethylcellosolve, butylcellosolve,
Phenyl cellosolve, methyl carbitol, ethyl carbitol, butyl carbitol, dioxane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, ethylene glycol dibutyl ether, propylene glycol, dipropylene glycol butyl ether, tripropylene glycol methyl ether, polypropylene glycol methyl ether Ether, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, 4-methyl-1,3-dioxolan-2-one etc.), esters (ethyl acetate, propyl acetate, hexyl acetate, methyl acetate, acetic acid) Propyl,
Diethyl succinate, dibutyl oxalate, diethyl maleate, benzyl benzoate, methyl cellosolve acetate,
Cellosolve acetate, carbitol acetate, etc.) and the like.

As the surfactant to be added to the developing solution of the present invention, an anionic surfactant, a nonionic surfactant, a cationic surfactant and a zwitterionic surfactant are used, and they are disclosed in Japanese Patent Application No. 2-206041. The surfactants mentioned are used. These surfactants can be used alone or in combination of two or more kinds.

Further, as the alkaline agent contained in the developing solution used in the present invention, (1) sodium silicate,
Potassium silicate, potassium hydroxide, sodium hydroxide,
Inorganic alkaline agents such as lithium hydroxide, sodium di- or tri-phosphate or ammonium salt, sodium metasilicate, sodium carbonate, ammonia, etc. (2) mono-, di- or trimethylamine, mono-, di- or triethylamine, mono- or diisopropylamine, n-butylamine, mono, di or triethanolamine, mono, di or triisopropanolamine, ethyleneimine,
Examples thereof include organic amine compounds such as ethylenediimine. The amount of the alkaline agent used is 0.05 to 20% by weight, preferably 0.2 to 10% by weight.

The development can be carried out by a method such as rubbing with a developing pad containing the above-mentioned developing solution or rubbing with a developing brush after pouring the developing solution onto the plate surface. By the above development, a printing plate from which the photosensitive layer and the silicone rubber in the unexposed area are removed, or a silicone rubber layer is removed to expose the photosensitive layer and a printing plate in which the silicone rubber layer remains in the exposed area can be obtained.

Conventionally, in the production of a lithographic printing plate, a halftone dot negative or the like is brought into close contact with a photosensitive layer, which is irradiated with a strong ultraviolet ray, for example, a high pressure mercury lamp or a metal halide lamp, and then an appropriate development is carried out. The method of developing with a liquid was taken.

However, in recent years, a method has been proposed in which the plate-making process is simplified by directly irradiating the photosensitive layer with an image using a laser beam. For example, U.S. Pat.
No. 664,737 describes a method for producing a lithographic printing plate by directly irradiating a recording material having an ultraviolet-sensitive layer, particularly a diazo-sensitive layer, on an aluminum support with a laser beam.

However, since this method uses what is conventionally known as an ultraviolet light-sensitive layer as the photosensitive layer, applying this to a laser beam does not affect the luminous efficiency of the laser and the photosensitive wavelength range of the photosensitive material. The disagreement between them was a significant disadvantage from an economic point of view. That is, the laser that can be used for plate making, for example, an argon ion laser, has a large total emission energy in the visible light region of 450 nm or more, and the emission efficiency of ultraviolet rays is less than 5% of the total emission energy. It was necessary to use a large laser of about 30W.

"Photopolymer Technology" (Nikkan Kogyo Shimbun, 1988) discloses a photopolymerizable composition containing a dye having absorption in the visible light region. Although it has sensitivity in the laser region, it is not sufficient. Therefore, it is necessary to use a high-power laser, which is problematic in terms of cost and size of the device.

The photosensitive layer of the present invention is sensitive to a low output visible light laser, and the laser beam used in the present invention is, for example, capable of continuous oscillation of He-Ne, He-Cd, argon, krypton or the like. Among them, an argon laser (output 0.1 to 5 W) is preferable in consideration of output energy, laser tube life, oscillation efficiency, and the like.

In the photosensitive layer of the present invention, a silver halide is used as a light absorber, and the image formation insoluble in a developer is amplified by an alkali treatment, so that a very high sensitivity can be achieved.

Further, since the chemical reaction for image formation is started only when the photosensitive layer comes into contact with the aqueous alkaline processing liquid, the adhesion between the non-image area photosensitive layer swollen by the alkaline processing liquid and the silicone rubber layer is improved. It is possible to make a plate excellent in image reproducibility (halftone dot reproducibility).

[0082]

EXAMPLES Hereinafter, the present invention will be described more specifically by way of examples.

Example 1 Synthesis of diazo resin-1 14.5 g (50 mmol) of p-diazodiphenylamine sulfate was dissolved in 40.9 g of concentrated sulfuric acid under ice cooling. 1.35 g (45 mmol) of paraformaldehyde was slowly added to the reaction solution so that the reaction temperature did not exceed 10 ° C.

The reaction mixture was added dropwise to 500 ml of ethanol under ice cooling, and the resulting precipitate was filtered. After washing with ethanol, the precipitate was dissolved in 100 ml of pure water, and a cold concentrated aqueous solution containing 6.8 g of zinc chloride was added to the solution. The generated precipitate was filtered, washed with ethanol, and dissolved in 150 ml of pure water. To this solution was added a cold concentrated aqueous solution in which 8 g of ammonium hexafluorophosphate was dissolved. The resulting precipitate was collected by filtration, washed with water, and dried to obtain diazo resin-1.

[0085] The aluminum plate aluminum plate manufacturing thickness 0.24mm of a 3% immersed in the aqueous sodium hydroxide solution was degreased, washed with water, under the condition of 5A / dm ² at a temperature 30 ° C. at 32% sulfuric acid aqueous solution Anodize for 10 seconds, wash with water, immerse in 2% aqueous sodium metasilicate solution at temperature 85 ° C for 37 seconds, and then water at temperature 90 ° C (pH 8.5)
The aluminum plate a was obtained by immersing in aluminum for 25 seconds, washing with water and drying.

An aluminum plate a (410 × 610 mm) was coated with a primer layer composition having the following composition, dried at 85 ° C. for 3 minutes, and then exposed at 1000 mJ / cm ^{2 on} the entire surface using a 3 KW ultra-high pressure mercury lamp. .. Furthermore, it is dried at 100 ℃ for 4 minutes and the thickness is 0.8.
A μm primer layer was formed.

(Primer Layer Composition) (1) Diazo Resin-1 8 Parts (2) 2-Hydroxyethyl Methacrylate, Methyl Methacrylate Copolymer Resin with Molar Ratio 40/60 92 Parts (3) γ-Methacryloxypropyl Trimethoxysilane 2 parts (4) Methylcellosolve 900 parts Next, a photosensitive composition having the following composition was applied on the primer layer and dried at 100 ° C. for 2 minutes to form a photosensitive layer having a thickness of 0.3 μm.

(Photosensitive composition) (Diacetone acrylamide)-(β-dimethylaminoethyl methacrylate)-(methacrylic acid) [molar ratio =
90: 4: 6] 2% of 40% by weight silver nitrate aqueous solution in 80% of 30% by weight isopropanol solution of copolymer (copolymer-1)
Was added and dissolved, and 40 ml of a 0.5 wt% methanol solution of lithium chloride was added at once at room temperature with stirring. A stable dispersion of very fine silver chloride particles was obtained (average particle size 0.06
μm). 70 ml of glycerin, 80 mg of triphenyl phosphate and 150 m of 4-N, N-diethylamine were added to 10 ml of this dispersion.
g and 3 mg of the sensitizing dye represented by the following formula (1) were added and dissolved to obtain a coating solution.

[0089]

[Chemical 6] Next, the following silicone rubber composition was applied onto the above-mentioned photosensitive layer so that the dry weight was 1.8 g / m ² , and dried at 90 ° C. for 10 minutes.

(Silicone rubber layer composition) Dimethylpolysiloxane having hydroxyl groups at both ends (Molecular weight 52,000) 100 parts Triacetoxymethylsilane 10 parts Dibutyltin laurate 0.8 parts Isopar E (manufactured by Esso Kagaku) 900 parts A 5 μm thick single-sided matt polypropylene film was laminated on the rubber layer to obtain a waterless planographic plate.

The waterless planographic plate obtained was placed under the 2.5 W argon laser of the recording device shown in FIG. 1 to record information from the information output device. The recording was completed in 1 minute. When this plate was treated with Developer A having the following composition for 1 minute, the photosensitive layer and the silicone rubber layer in the unexposed area were removed, and a good printing plate corresponding to the information was obtained.

Using the FOGRA chart (halftone dot chart of 1% to 99%), the obtained plate material was exposed with a 2 KW metal halide lamp at a distance of 1 m for 5 seconds and developed in the same manner as above. The halftone dot reproducibility was evaluated.

The above results are shown in Table 2.

Further, the image area of the printing plate was able to be dyed vividly by applying a dyeing solution having the following composition to the cloth, lightly rubbing on the plate, and washing with water.

(Developer-1) β-anilinoethanol 0.5 part Propylene glycol 1.0 part p-tert-butylbenzoic acid 1.0 part Potassium hydroxide 1.0 part Polyoxyethylene lauryl ether 0.1 part Potassium sulfite 2.0 parts Potassium metasilicate 3.0 parts Water 91 parts (Staining solution) Solfite (Kuraray Isoprene Chemical Co., Ltd. solvent) 20 parts Leodol TW-0120 (Kao Co., Ltd. surfactant) 0.5 part Benzyl alcohol 5.0 parts Victoria Pure Blue BOH 1.0 part Water 100 parts

Examples-2 to 4 The same procedures as in Example-1 were carried out except that the primer layer composition of Example-1 was changed as follows and the photosensitive composition was changed to the composition shown in Table 1. I got a waterless planographic printing. (Primer layer composition) (1) 100 parts of a copolymer resin (Mw = 4.0 × 10 ⁴ ) of 2-hydroxyethyl methacrylate and methyl methacrylate in a molar ratio of 34/66 (2) 80 parts of pentaerythritol triacrylate

[0097]

[Chemical 7] (5) KET-YELLOW402 (Yellow pigment manufactured by Dainippon Ink and Chemicals, Inc.) 8 parts (6) Zinc oxide (average particle size: 0.12μ) 20 parts (7) Urethane acrylate

(Photosensitive composition) (described in Table 1)

When exposure and development were carried out in the same manner as in Example-1, the silicone rubber layer in the unexposed portion was removed, and a printing plate in which halftone dots were reproduced well could be obtained. In addition, the result of measuring the dot reproducibility in the same manner as in Example 1 is shown in Table 2.
Shown in.

[0100]

[Table 1]

[0101]

[Chemical 8]

Comparative Examples 1 to 3 The waterless planographic printing plate of Example 1 in each of JP-A 1-118843, JP-A 49-7005 and JP-A 49-8306 was prepared, and Example 1 of the present invention was prepared. Recording was carried out with an argon laser in the same manner as, but no image could be formed.

Further, in order to measure the dot reproducibility, exposure was performed for 50 seconds at a distance of 1 m with a 2 kW metal halide lamp in the same manner as in Example 1 of the present invention, and the development shown in Example 1 of each of the above publications was carried out. It processed and evaluated as Comparative Examples 1-3. The results are shown in Table 2.

Image formation was not possible with the same exposure time of 5 seconds as in the present invention.

[0105]

[Table 2]

[0106]

According to the method for making a waterless planographic printing plate of the present invention,
It is possible to provide a waterless planographic printing plate having high sensitivity and excellent image reproducibility (halftone dot reproducibility) even in recording with a low output visible light laser.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus used in an embodiment of the present invention.

[Main reference numbers]

 1 Argon-ion-laser 2,5,12 Laser beam 3,8,9,13 Reflector 6 Reflective optical system 7 Motor 10 version 11 Information output device

Claims (1)

[Claims] 1. A photosensitive lithographic printing plate which does not require a fountain solution and has a photosensitive layer and a silicone rubber layer on a support in this order, and the photosensitive layer contains a silver halide, an aromatic amine and a polymer having an aromatic hydroxyl group. A plate-making method comprising developing the plate with an aqueous alkaline solution.