JP2520687B2 - Waterless planographic printing plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a waterless lithographic printing plate precursor capable of printing without using a fountain solution.

[Conventional technology and its problems]

Several inventions have been made in the past regarding lithographic printing plate precursors that can be printed without using fountain solution. For example, Japanese Patent Publication No. 44-23042, Japanese Patent Publication No. 46-16044, and Japanese Patent Publication No. 51-1708.
No. 1, Japanese Patent Publication No. 54-26923, Japanese Patent Publication No. 56-80064, Japanese Patent Publication No. 5
There is No. 5-22781. Among them, as the photosensitive layer of the positive type waterless planographic printing plate, JP-B-54-26923 and JP-B-56-231 are used.
The type using a photopolymerizable photosensitive layer disclosed in JP-A No. 50 and the like and the type using a photodimerizable photosensitive layer disclosed in JP-B-55-22781 are common.

In the type that uses a photopolymerizable photosensitive layer, photoadhesion occurs between the silicone rubber layer and the photosensitive layer upon exposure, so an adhesion aid (such as a silane coupling agent) that normally provides adhesion to the photosensitive layer is added to the silicone rubber layer. You don't have to. When such photoadhesion is used, by developing with a solvent that swells the silicone rubber layer, only the unexposed silicone rubber layer can be removed without eluting the lower photopolymerization layer. However, since the image forming method utilizing photoadhesion is essentially used, the reproducibility of ropes in the shadow portion where the light amount is insufficient is not always sufficient. In order to solve this problem, an adhesion aid such as an aminosilane coupling agent is added to the silicone rubber layer, and the silicone rubber layer and the photosensitive layer are firmly adhered to each other from the beginning, and a developer for dissolving the photosensitive layer is used. There is a method of forming an image by dissolving the unexposed portion to the lower photopolymerized layer. If such a method is adopted, the reproducibility of the rope points in the shadow portion is improved, but conversely, with respect to the reproducibility of the rope points in the highlight portion, since the photosensitive layer and the silicone layer are more strongly adhered with time, the developability is improved. It sometimes deteriorated and became defective. In addition to this, when a photopolymerizable photosensitive layer is used, it has a drawback that the sensitivity greatly varies depending on the temperature at the time of exposure or the standing time from the time after exposure to the time of development. It becomes a problem in some cases.

On the other hand, the type using a photodimerization type photosensitive layer is different from the photopolymerization type photosensitive layer in that sufficient photoadhesion cannot be obtained.Therefore, a silane coupling agent or the like is added to the silicone rubber layer as an adhesion aid, and the silicone rubber is previously prepared. It is necessary to have a strong bond between the layer and the photosensitive layer. In this case, unlike the photopolymerizable photosensitive layer, the disadvantage that the sensitivity greatly varies depending on the temperature during exposure or the standing time from exposure to development is eliminated, but a silane coupling agent or the like is added as an adhesion aid. Therefore, as in the case of the photopolymerizable photosensitive layer, it is recognized that the reproducibility of the highlight points in the highlight portion deteriorates with time.

[Purpose of the present invention]

Therefore, an object of the present invention is to provide a waterless lithographic printing plate precursor which is excellent in image reproducibility, does not vary in sensitivity depending on the temperature at the time of exposure, and can be processed by a developer mainly containing water or alkaline water. Is.

[Means for solving the problem]

The present inventor, in a waterless lithographic printing plate precursor in which a photosensitive layer and a silicone rubber layer are laminated in this order on a substrate, a silicone rubber which is crosslinked by an addition reaction of a SiH group and a —CH═CH— group is used as the silicone rubber layer. By using a photosensitive polymer compound having a photodimerizable unsaturated double bond and a carboxylic acid group or a salt thereof as a photosensitive layer, it can be treated with a developer mainly composed of water or alkaline water, and exposed. It was found that there is little sensitivity fluctuation due to the environment at the time and a waterless planographic printing plate excellent in image reproducibility can be obtained.
The present invention has been completed based on this finding.

That is, the present invention relates to a substrate, a photosensitive layer provided on the substrate, and a SiH group provided on the photosensitive layer and -CH = CH.
In a waterless lithographic printing plate precursor comprising a silicone rubber layer which is crosslinked by an addition reaction with-, the photosensitive layer has at least two side chains of the following general formula (I): (Wherein, R ₁ and R ₂ each represents an alkyl group, and R ₁
R ₂ and R ₂ may together form a 5-membered ring or a 6-membered ring. ) And a water- or alkali-water-soluble photosensitive polymer compound having a group represented by and a side chain of at least one carboxylic acid group or a salt thereof, a waterless lithographic printing plate precursor To do.

 Hereinafter, the present invention will be described in detail.

The waterless lithographic printing plate precursor of the present invention must be flexible enough to be set in an ordinary printing machine and capable of withstanding the load applied during printing. Therefore, as a typical substrate, a coated paper, a metal plate, a plastic film such as polyethylene terephthalate, rubber, or a composite substrate thereof can be cited. It is possible to further coat a primer layer or the like on the surface of these substrates for the purpose of preventing halation and for other purposes to form a support.

As the primer layer, various photosensitive polymers described in JP-A-60-229031, which are exposed and cured before laminating the photosensitive layers, are disclosed in JP-A-62-50760. A heat-cured epoxy resin and a hardened gelatin layer disclosed in Japanese Patent Application No. 61-281194 are used. In addition, a casein layer with a dura mater is also effective. In addition, additives such as dyes, printout agents, polymerizable monomers as photoadhesives, and photopolymerization initiators may be internally added to these primer layers for the purpose of preventing halation and other purposes. Generally, the coating thickness of the primer layer is
It is a ^{2g / m 2 ~10g / m 2} .

The polymer having a photosensitive group represented by the general formula (I) in its side chain, which is used in the photosensitive layer of the present invention, is disclosed in, for example, JP-A-52
-988 (corresponding U.S. Pat.
ekulare Chemi) 115 (1983) pages 163-181, JP
49-128991 to 49-128993, 50-5376 to 50-
5380, 53-5298 to 53-5300, 50-50107,
51-47940, 52-13907, 50-45076, 52
No. 121700, No. 50-10884, No. 50-45087, West German Patent Nos. 2,349,948, and 2,616,276.

The present invention is a photosensitive polymer compound having an average of 2 or more maleimide groups per molecule in the side chain among these, and 1 or more carboxylic acid groups or salts thereof per molecule.

In the general formula (I), R ₁ and R ₂ are preferably alkyl groups having 1 to 4 carbon atoms, and particularly preferably methyl groups. The alkyl group may have a substituent.

It is preferable to use a polymer having a molecular weight of 1,000 or more. More preferably, the molecular weight is 10,000-50
It is a million.

Such polymers are represented by general formulas (II) to (IV): (In the formula, R ₁ and R ₂ have the same meanings as described above, n is an integer, and preferably 1 to 6.) and a monomer having a carboxylic acid group, for example, acrylic acid, It is easily prepared by copolymerizing with methacrylic acid, crotonic acid, itaconic acid and the like. These copolymers may be converted into a salt form by further neutralizing with sodium hydroxide, potassium hydroxide or an amine.

Depending on the purpose, other monomers (for example, hydroxyalkyl methacrylate, hydroxyalkyl acrylate, alkyl methacrylate alkyl acrylate, benzyl methacrylate, etc.) may be added to the above copolymer.
Allyl methacrylate, acrylonitrile, styrene,
Aminoalkyl methacrylate, quaternary aminoalkyl methacrylate, etc.) may be copolymerized.

Among these copolymers, N- [2- (methacryloyloxy) ethyl] -as described in Di Angevante Macromoleklaki Chemi 128 (1984), pp. 71-91.
A copolymer of 2,3-dimethylmaleimide and methacrylic acid or acrylic acid is preferable. Further, a multicomponent copolymer obtained by polymerizing a vinyl monomer different from the above vinyl monomer in the coexistence is also preferable.

The acid value before neutralizing the polymer used in the present invention is preferably 20 to 200. As the molecular weight, 1000 or more,
It is preferable to use those having a viscosity of 10,000 to 500,000, particularly preferably 20,000 to 300,000.

If necessary, a sensitizer capable of sensitizing the photosensitive polymer compound may be added to the photosensitive layer of the present invention.

Specific examples of such sensitizers include benzoin, benzoin methyl ether, benzoin ethyl ether,
2,2-dimethoxy-2-phenylacetophenone, 9-
Fluorenone, 2-chloro-9-fluorenone, 2-methyl-9-fluorenone, 9-anthrone, 2-bromo-9-anthrone, 2-ethyl-9-anthrone, 9,10
-Anthraquinone, 2-ethyl-9,10-anthraquinone, 2-t-butyl-9,10-anthraquinone, 2,6-dichloro-9,10-anthraquinone, xanthone, 2-methylxanthone, 2-methoxyxanthone, di- Benzalacetone, p- (dimethylamino) phenyl styryl ketone, p- (dimethylamino) phenyl p-methyl styryl ketone, benzophenone, p- (dimethylamino) benzophenone (or Michler's ketone), p- (diethylamino) benzophenone, benzanthrone And so on.

Further, thioxanthone derivatives, such as 2-chlorothioxanthone, 2-isopropylthioxanthone, and dimethylthioxanthone, and German Patent Nos. 3018891 and 311.
7568, European Patent 33730, British Patent 2
Examples include substituted thioxanthones as described in Japanese Patent No. 075506 and compounds represented by the following general formula (V).

In the formula, Z is a group of non-metal atoms necessary for forming a heterocyclic nucleus containing nitrogen. Examples of the nitrogen-containing heterocyclic nucleus formed with Z include thiazoles such as benzothiazole, α-naphthothiazole and β-naphthothiazole, oxazoles such as benzoxazole and β-naphthoxazole, and selenazoles such as benzoselenazole. , Imidazoles such as imidazole and benzimidazole, isoindoles such as 3,3-dimethylindolenine, quinolines such as quinoline and isoquinoline, 1,3,4-
Diazoles such as oxazoazole, 1,3,4-thiadiazole, 1,3,4-selenadiazole, triazoles such as 1,2,4-triazole, pyrazine, quinoxaline, S-triazine, phenanthridine Etc. can be mentioned. The nitrogen-containing heterocyclic nucleus formed together with Z may have a substituent, and examples of the substituent include an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group, a methoxy group, an ethoxy group. An alkoxy group having 1 to 6 carbon atoms, a halogen atom such as chlorine and bromine, a cyano group, an amino group, an amino group substituted with an alkyl group having 1 to 4 carbon atoms such as a dimethylamino group, and a carbomethoxy group. Carbon number of 1
A substituted or unsubstituted aryl group having 6 to 10 carbon atoms such as a carboalkoxy group having 4 to 4 alkyl groups, a phenyl group, p-methoxyphenyl, and p-chlorophenyl group.

When R ₃ is an aryl group, it represents monocyclic and polycyclic compounds having 6 to 14 carbon atoms such as phenyl and naphthyl. In the case of a substituted aryl group, as the substituent, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an amino group, and 1 to 6 carbon atoms. There are amino groups substituted with alkyl groups, fluorine groups, halogen atoms such as chlorine and bromine, and the like. Further, the alkyl group used as the above-mentioned substituent is further methoxy,
It may have an alkoxy group having 1 to 2 carbon atoms such as ethoxy, or a halogen atom such as chlorine as a substituent.

Preferable examples of the substituent of the substituted aryl group include an alkyl group having 1 to 4 carbon atoms such as a methyl group and an ethyl group, an alkoxy group having 1 to 4 carbon atoms such as a methoxy group and an ethoxy group, and a dimethylamino group. , An amino group substituted with an alkyl group having 1 to 4 carbon atoms such as a diethylamino group and a halogen atom such as fluorine, chlorine and bromine.

When R ₃ is a substituted or unsubstituted heterocyclic group, the heterocycle is a monocyclic or polycyclic compound containing at least one atom of nitrogen, oxygen and sulfur, and preferably 5 such as furan, pyrrole or pyridine. Alternatively, it is a 6-membered heteroaromatic compound.

In the case of a substituted heterocyclic group, examples of the substituent include the same as those used for the above substituted aryl group.

These sensitizers are used alone or in combination. The amount added is preferably 0.5 to 20%, more preferably 3 to 10% of the total photosensitive layer composition.

In addition to the above, it is preferable to further add a thermal polymerization inhibitor, and in some cases, a dye or pigment for the purpose of coloring the photosensitive layer, or a pH indicator or the like as a print-out agent can be added.

The thickness of the photosensitive layer as described above is preferably as thin as possible in the case of the plate making method excluding the photosensitive layer in the image area and the silicone rubber layer in the developing step after image exposure, but as a general guideline, It is desirable to be selected from the range of 5μ or less, particularly 0.1 to 1μ.

The silicone rubber layer in the present invention serves as a printing ink repellent layer, and when the thickness is small, there are problems such as a decrease in ink repulsion property and easy scratching, and when the thickness is large, developability deteriorates. From the point, the thickness is 0.5
It is preferably μ to 5 μ.

The formation of the silicone rubber layer in the present invention is obtained by cross-linking by an addition reaction of SiH group and -CH = CH- group, and the obtained silicone rubber layer is ink repellent as compared with the condensation type. It has the advantage of being excellent. Furthermore, in addition to being excellent in adhesive strength to the photosensitive layer used in the present invention, in the condensation type, curing failure occurs when carboxylic acid is present in the photosensitive layer, whereas in the addition type, carboxylic acid is present. Even if it cures sufficiently. Since the carboxylic acid can be present in the photosensitive layer in this manner, it has the feature that it can be developed with a developer mainly containing water or alkaline water.

Examples of the -CH = CH- group include a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, an alkenylene group, an alkynyl group and an alkynylene group, and an aromatic -CH =
CH-bonds are not included.

The silicone rubber of the present invention comprises a polyvalent hydrogenorganopolysiloxane and two or more —CH═CH— in one molecule.
It is obtained by a reaction with a polysiloxane compound having a bond, and preferably (1) 100 parts by weight of organopolysiloxane which has at least two alkenyl groups (preferably vinyl groups) directly bonded to a silicon atom in one molecule. Parts (2) 0.1 to 1000 parts by weight of organohydrogenpolysiloxane having at least two SiH bonds in one molecule (3) 0.00001 to 10 parts by weight of an addition catalyst, which is cured and crosslinked. Ingredient (1)
The alkenyl group may be at the terminal or in the middle of the molecular chain, and the organic group other than the alkenyl group is a substituted or unsubstituted alkyl group or aryl group. Ingredient (1)
It is optional to have a small amount of hydroxyl groups. Ingredient (2)
Reacts with component (1) to form silicone rubber,
It also plays the role of imparting adhesiveness to the photosensitive layer. Ingredient (2)
The hydrogen group of may be at the end of the molecular chain or at the middle.
The organic group other than hydrogen is selected from the same groups as the component (1). It is preferable that the organic groups of the component (1) and the component (2) have a total of 60% or more methyl groups in terms of improving the ink resilience. The molecular structures of the components (1) and (2) may be linear, cyclic or branched, and it is preferable that at least one of them has a molecular weight of more than 1,000 from the viewpoint of rubber physical properties. It is preferable that the molecular weight of (1) exceeds 1,000.

Examples of the component (1) include α, ω-divinylpolydimethylsiloxane, (methylvinylsiloxane) (dimethylsiloxane) copolymer of both terminal methyl groups, and the like.
As the component (2), polydimethylsiloxane having hydrogen groups at both terminals, α, ω-dimethylpolymethylhytrogensiloxane, (methylhydrogensiloxane) having both terminal methyl groups (dimethylsiloxane) copolymer, cyclic polymethyl Hydrogen siloxane etc. are illustrated.

The addition catalyst of the component (3) is arbitrarily selected from known catalysts, and is particularly preferably a platinum compound, such as platinum alone, platinum chloride, chloroplatinic acid, and olefin-coordinated platinum. For the purpose of controlling the curing rate of these compositions, it is also possible to add a crosslinking inhibitor such as a vinyl group-containing organopolysiloxane such as tetracyclo (methylvinyl) siloxane or a carbon-carbon triple bond-containing alcohol. is there.

These compositions have the characteristic that, when the three components are mixed, an addition reaction occurs and curing starts, but the curing rate increases rapidly as the reaction temperature increases. Therefore, for the purpose of prolonging the pot life of the composition until rubberization, and shortening the curing time on the photosensitive layer, the curing conditions of the composition are a temperature condition in which the characteristics of the substrate and the photosensitive layer are not changed,
Further, it is preferable to keep the temperature at a high temperature until it is completely cured, from the viewpoint of the stability of the adhesive force with the photosensitive layer.

In addition to these compositions, a known adhesion-imparting agent such as alkenyltrialkoxysilane may be added, or a hydroxyl group-containing organopolysiloxane or a hydrolyzable functional group-containing silane (or siloxane) which is a composition of a condensation type silicone rubber. ) Is optional, and it is also optional to add a known filler such as silica for the purpose of improving rubber strength.

It is optional to further coat various silicone rubber layers on the silicone rubber layer having the characteristics of the present invention in the waterless lithographic printing plate precursor described above, and between the photosensitive layer and the silicone rubber layer. It is optional to provide an adhesive layer between the photosensitive layer and the silicone rubber layer for the purpose of increasing the adhesive strength or preventing poisoning of the catalyst in the silicone rubber composition. For the surface protection of the silicone rubber layer, a transparent film such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, or cellophane is laminated on the silicone rubber layer,
A polymer coating may be applied.

The waterless lithographic printing plate precursor according to the present invention is exposed through a transparent original image and then developed with a developing solution capable of dissolving or swelling the photosensitive layer in the image area or a developing solution capable of swelling the silicone rubber layer. In this case, there are cases where the photosensitive layer in the image area and the silicone rubber layer thereon are removed, and cases where only the silicone rubber layer in the image area is removed. This can be controlled by the strength of the developer.

As the developing solution used in the present invention, those known as a developing solution for a photosensitive lithographic printing plate precursor that does not require fountain solution can be used. For example, aliphatic hydrocarbons (hexane, heptane, "Isopar E, H, G" (trade name of aliphatic hydrocarbons manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene) , Xylene, etc.),
Alternatively, a halogenated hydrocarbon (such as trichlene) to which the following polar solvent is added is preferable.

・ Alcohols (methanol, ethanol, benzyl alcohol, etc.) ・ Ethers (methyl cellosolve, ethyl cellosolve,
Butyl cellosolve, methyl carbitol, ethyl carbitol, butyl carbitol, dioxane, etc.) Ketones (acetone, methyl ethyl ketone, etc.), esters (ethyl acetate, methyl cellosolve acetate, cellosolve acetate, carbitol ate, etc.) In addition, the above organic solvents Water added to the system developer, or the above organic solvent solubilized in water using an activator, or an alkaline agent such as sodium carbonate, monoethanolamine, dietanoamine, triethanolamine. , Sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, sodium borate and the like, and in some cases, tap water or alkaline water can be simply used as the developing solution.

Further, a dye such as crystal violet or astrazone red can be added to the developing solution to dye the image area in the same manner as the development.

The development can be performed by a known 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. As a result, the silicone rubber layer and the photosensitive layer in the image area are removed, and the surface of the substrate or the primer layer is exposed, and that area becomes the ink receiving area, or only the silicone rubber layer in the image area is removed and the photosensitive layer is exposed. That portion may serve as an ink receiving portion.

〔The invention's effect〕

The waterless lithographic printing plate precursor according to the present invention has a photosensitive layer on a substrate,
It has a layer structure in which a silicone rubber layer that is crosslinked by an addition reaction is laminated in this order, and in the photosensitive layer, at least the photosensitive group represented by the general formula (I) and a carboxylic acid group or a salt thereof is used as a side chain. By including the polymer having,
A waterless lithographic printing plate precursor was obtained in which the sensitivity did not fluctuate depending on the environment during printing and could be processed with a relatively mild developing solution, and the image reproducibility did not deteriorate over time.

Next, the present invention will be described with reference to examples, but the present invention is not limited thereto.

Example 1 A 0.3 mm smooth aluminum plate degreased by a conventional method was coated with the following composition for a primer layer so that the dry weight was 8.0 g / m ^2, and heated at 120 ° C. for 2 minutes to dry-harden the film. It was

Milk casein 98 parts by weight Glyoxal solution (40% aqueous solution, Wako Pure Chemical Industries, Ltd.) 2 parts by weight γ-glycidoxypropyltri (β-methoxyethoxy) silane 3 parts by weight 4 parts by weight of potassium hydroxide 2000 parts by weight of pure water An aluminum plate coated with the above primer layer was immersed in a dyeing solution having the following composition for 1 minute, dyed, washed with water and dried at room temperature.

2000 parts by weight of pure water The following photosensitive composition was applied on an aluminum plate coated with the dyed primer layer so that the dry weight was 1 g / m ² , and dried at 100 ° C. for 1 minute.

Methyl methacrylate / N- [2- (methacryloyloxy) ethyl] -2,3-dimethylmaleimide / methacrylic acid = 15/65/20 (weight ratio) 90 parts by weight copolymer 7-methylthioxanthone-3-carboxylate ethyl ester Ten
Parts by weight Propylene glycol monomethyl ether acetate 11
00 parts by weight Methyl ethyl ketone 1100 parts by weight Next, the following silicone rubber composition was applied on the photosensitive layer so that the dry weight was 2.0 g / m ^2, and dried at 140 ° C. for 2 minutes to obtain a silicone rubber cured layer. .

α, ω-divinylpolydimethylsiloxane (average molecular weight
300,000) 90 parts by weight α, ω-divinylpolymethylhydrogensiloxane (average molecular weight 2,500) 6 parts by weight Olefin-chloroplatinic acid (10% toluene solution) 20 parts by weight Inhibitor (10% toluene solution) 10 parts by weight Isopar G (Manufactured by Esso Kagaku Co., Ltd.) 1400 parts by weight Toluene 210 parts by weight A single-sided matt polypropylene film having a thickness of 9 μ was laminated on the surface of the silicone rubber layer obtained as described above to obtain a waterless planographic printing original plate. .

FT26V UDNS ULTRA-PLUS FLIP-TOP PLATE MAK made by Nuark Co., Ltd.
After exposing for 30 counts by ER, the laminated film was peeled off and immersed in a developing solution consisting of 8 parts by weight of benzyl alcohol, 3 parts by weight of sodium isopropylnaphthalene sulfonate, 1 part by weight of sodium carbonate and 88 parts by weight of water for 1 minute to develop a developing pad. When lightly rubbed with, the photosensitive layer and the silicone rubber layer in the unexposed portion were removed. In this way, a waterless planographic printing plate was obtained in which the image of the positive film was faithfully reproduced over the entire surface of the printing plate.

Using this plate, a Heidelberg GTO printing machine without a dampening water supply device was used to print with TOYO KING ULTRA TUK AQUALES G black ink, and a print showing faithful image reproducibility was obtained.

Example 2 A desensitized aluminum plate having a thickness of 0.3 mm was coated with a photosensitive primer solution having the following composition and dried at 140 ° C. for 1 minute. The coating weight after drying was 4 g / m ² .

Epikote 1255-HX-30 (30% solution) (Yukaka Shell Epoxy Co., Ltd .: condensate of bisphenol A and epichlorohydrin) 5 g Takenate D-110N (75% solution) (Takeda Pharmaceutical Co., Ltd.)
Made: polyfunctional isocyanate compound) 1.5 g pentaerythritol triacrylate 1 g 7-methylthioxanthone-3-carboxylate ethyl 0.5
g Victoria Pierre BOH 0.005g Methyl ethyl ketone 30g Propylene glycol monomethyl ether acetate 30g Next, apply a water-soluble photosensitive solution having the following composition,
It was dried at ° C for 1 minute. The dry coating weight was 1.0 g / m ² .

N- [2- (methacryloyloxy) ethyl-2,3-
Dimethylmaleimide / 2-hydroxyethylmethacrylate / methacrylic acid = 70/20/10 (weight ratio) Sodium salt of copolymer (10% aqueous solution) 50g Water 40g Methanol 10g Next, apply the following silicone rubber composition on the photosensitive layer. It was applied to a dry weight of 1.2 g / m ² and dried at 140 ° C. for 2 minutes to obtain a silicone rubber cured layer.

α, ω-divinylpolydimethylsiloxane (average molecular weight
600,000) 90 parts by weight α, ω-dimethylpolymethylhydrogensiloxane (average molecular weight 2,500) 3 parts by weight Olefin-chloroplatinic acid (10% toluene solution) 20 parts by weight Inhibitor (10% toluene solution) 10 parts by weight Isopar G (EXXON Chemical Co., Ltd.) 1400 parts by weight Toluene 210 parts by weight A 12 μm thick single-sided matt polypropylene film was laminated on the surface of the silicone rubber layer obtained as described above to obtain a waterless planographic printing original plate.

Image exposure was performed on this printing base plate in the same manner as in Example 1, and then 50
After immersing in warm water at ℃ for 30 seconds, rub the plate surface with a sponge for 30 seconds to remove the silicone rubber layer and the photosensitive layer in the unexposed area, and the waterless planographic printing faithfully reproduced the image of the positive film over the entire printing plate. A printing plate was obtained.

Example 3 A photosensitive solution having the following composition was applied to an aluminum substrate coated with the casein primer layer of 8 g / m ² used in Example 1 and dried at 100 ° C. for 1 minute. Dry coating weight is 1.0 g / m ²
Met.

Methyl methacrylate / N- [2- (methacryloyloxy) ethyl] -2,3-dimethylmaleimide / methacrylic acid = 15/65/20 sodium salt 5 parts by weight 7-methylthioxanthone-3-carboxylate ethyl 0.5
Parts by weight Leuco Crystal Violet 0.05 parts by weight Methyl ethyl ketone 35 parts by weight Propylene glycol monomethyl ether acetate 25
0.01 parts by weight Fluorine nonionic surfactant 0.01 parts by weight The following silicone rubber composition was applied on the photosensitive layer so that the dry weight was 2.0 g / m ² , dried at 140 ° C. for 2 minutes, and the cured silicone rubber layer Got

α, ω-divinylpolydimethylsiloxane (average molecular weight
600,000) 90 parts by weight α, ω-dimethylpolymethylhydrogensiloxane (average molecular weight 2,500) 5 parts by weight Olefin-chloroplatinic acid (10% solution in toluene) 20 parts by weight Inhibitor (10% solution in toluene) 10 parts by weight CH ₂ = CHCH ₂ Si (OCH ₃ ) ₃ 1 part by weight KF410 (Shin-Etsu Chemical: Silicone release agent) 0.5 part by weight Isopar G (Esso Chemical Co., Ltd.) 1400 parts by weight Toluene 210 parts by weight Produced as described above A polyethylene terephthalate film having a thickness of 8 μ was laminated on the prepared plate to obtain a printed plate.

A positive film was brought into close contact with this printing base plate, exposed, and developed using the following developer.

Benzyl alcohol 8 parts by weight 87 parts by weight of water After that, only the unexposed portion of the primer layer was dyed with the following dyeing solution to obtain a waterless planographic printing plate having excellent image reproducibility.

Water 99.5 parts by weight Crystal Violet 0.5 parts by weight Example 4 A casein solution consisting of the following solution was applied in place of the casein primer of Example 3 and dried at 120 ° C. for 1 minute. The dry coating weight was 8 g / m ² .

Casein 60 parts by weight Na ₂ CO ₃ 4.2 parts by weight TiO ₂ dispersed gelatin (TiO ₂ content 56% by weight) 10 parts by weight Tartrazine 2 parts by weight Water 1000 parts by weight Furthermore, the following casein hardener is applied onto
C., dried for 1 minute.

Water 30 parts by weight Methanol 70 parts by weight Using the primer layer-coated aluminum substrate thus obtained, a waterless planographic printing plate excellent in tone reproducibility was obtained in the same manner as in Example 3 except for the above.

Claims (1)

(57) [Claims] 1. A water comprising a substrate, a photosensitive layer provided on the substrate, and a silicone rubber layer which is crosslinked by an addition reaction between a SiH group and a —CH═CH— group provided on the photosensitive layer. In the lithographic printing plate precursor, the photosensitive layer has at least two side chains in the following general formula (I): (Wherein, R ₁ and R ₂ each represents an alkyl group, and R ₁
R ₂ and R ₂ may together form a 5-membered ring or a 6-membered ring. ) And a water- or alkali-water-soluble photosensitive polymer compound having a group represented by: and a side chain of at least one carboxylic acid group or a salt thereof, a waterless lithographic printing plate precursor.