JPH04190358A - Photosensitive planographic printing plate needing no damping water - Google Patents

Abstract

PURPOSE:To acquire superior photo curing characteristic and damage resistance of a primer and restrain influence of damage of a support body and others to the utmost by having a primer layer contain more than two kinds of polymers the glass transition temperature (Tg) of which is different at least by 5 deg.C, an ethylenic unsaturated monomer or oligomer and a photochemical polymerization starting agent and photo cured before applying a photosensitive layer. CONSTITUTION:A primer layer contains more than two kinds of polymers the glass transition temperature (Tg) of which is different at least by 5 deg.C, an ethylenic unsaturated monomer or oligomer and a photochemical polymerization starting agent and is photo cured before applying a photosensitive layer. The amount of the ethylenic unsaturated monomer or oligomer in the primer layer is 10 - 90 weight%. Consequently, even if this is used as a support body without applying active processing on an aluminium plate, it is superior in adhesivity with the primer layer and in time-series shelf life.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photosensitive lithographic printing plate that does not require dampening water, and more particularly relates to a photosensitive lithographic printing plate that does not require dampening water and has a photopolymerizable brimer layer.

[Prior art] Conventionally, in lithographic printing, it was necessary to perform printing by making use of the lipophilicity of the image area and the hydrophilicity of the non-image area, and by maintaining a delicate balance between water and ink, which required considerable skill. Needed.

In other words, in the conventional printing method that requires dampening water, an image-like lipophilic portion is formed by passing an image film through a plate material coated with a lipophilic photosensitive layer on a hydrophilic support, and then developing it. A printing plate is prepared by providing a hydrophilic area which is a non-image area. During printing, water is first transferred to the non-image areas, and then ink is transferred. Ink does not adhere to non-print areas where water is present, but only to print areas. However, this method
It is difficult to control the delicate balance between the dampening water and the ink, which can cause emulsification of the ink, or the ink may mix with the dampening water, causing poor ink density and background smudges, which can lead to major problems such as wasted paper. had.

For this reason, attempts have been made to develop lithographic printing plates that do not require dampening water, and such plates have a structure in which a primer layer, a photosensitive layer, and a silicone layer are provided in this order on a support. Lithographic printing plates are known.

In the photosensitive lithographic printing plate that does not require dampening water as described above, for example, Japanese Patent Publication No. 6L-54219,
Thermosetting type such as epoxy resin described in JP-A-62-194255, etc., or JP-A-60-229031
A typical example is a photocurable type that utilizes photocrosslinking, etc., as described in the above publication.

[Problems to be Solved by the Invention] However, in the case of the above-mentioned thermosetting primer layer, since the primer layer is coated on the support and then heated and cured, the production efficiency is poor and it is economically disadvantageous. In addition, when using a photo-crosslinkable primer layer, there are problems such as extremely low sensitivity for curing the primer when the film is made thick. Therefore, a primer layer that satisfies all of these requirements has been desired.

In addition, in a photosensitive lithographic printing plate that does not require dampening water and uses a primer layer as described above, when it is coated using an aluminum plate as a support, the adhesion between the primer layer and the aluminum plate is insufficient; For this reason, aluminum plates subjected to various activation treatments have been used in the past. Since such poor adhesion occurs particularly when the printing plate is folded, improvements in these problems have been desired.

It is known that some kind of silane coupling agent is used to improve the adhesion as described above, and photosensitive lithographic printing plates that do not require dampening water using such silane coupling agents can be used especially at high temperatures. It had the disadvantage that image characteristics deteriorated when stored under high humidity conditions.

Accordingly, an object of the present invention is to provide a novel photosensitive lithographic printing plate that does not require dampening water and eliminates the above-mentioned drawbacks. In particular, the object of the present invention is to provide a photosensitive lithographic printing plate that does not require dampening water, has excellent photocurability of the brimer, has excellent scratch resistance, can suppress the effects of scratches on the support as much as possible, and is economical. Our goal is to provide the following. Another object of the present invention is to provide a photosensitive lithographic printing plate that does not require dampening water and has excellent adhesion with a primer layer even when used as a support without subjecting an aluminum plate to activation treatment, and has excellent storage stability over time. It's right there.

[Means for Solving the Problems] In view of the above problems, the present inventors have conducted extensive research and found that the above object of the present invention is to form at least a primer layer, a photosensitive layer and a silicone rubber layer on a support from the support side. In the photosensitive lithographic printing plate that does not require dampening water, the primer layer has a small amount of a) two or more polymers 1 having glass transition temperatures (Tg) different from each other by at least 5° C., and b) an ethylenically unsaturated monomer or oligomer. , and C) a photopolymerization initiator, and is photocured before coating the photosensitive layer, and is achieved by providing a dampening water-free photosensitive lithographic printing plate. I found out.

The present invention will be explained in more detail below.

The two or more polymers with glass transition temperatures (Tg) different by at least 5°C used in the dampening water-free photosensitive lithographic printing plate of the present invention are preferably acrylic resins, urethane resins, and polyester resins. Especially preferably, acrylic resin is used. Examples of such acrylic resins include 2-hydroxyethyl (meth)acrylate-h, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, or copolymers thereof. Preferably, 2-hydroxyethyl methacrylate, methyl methacrylate, ethyl acrylate,
A copolymer with butyl acrylate or the like is used.

In the present invention, acrylic compounds and methacrylic compounds are collectively referred to as [(meth)acrylic.

In the present invention, the two or more types of polymers having Tg different by at least 5°C may be those having Tg different from each other by at least 5°C, and preferably have Tg of 5 to 5°C.
Two or more types of polymers differing by 30°C are used. For example, such a polymer has an absolute value of Tg of 140 to 1.
00°C can be used.

In addition, the two or more types of polymers may have the same or different constituent units as long as their Tg differs by 5°C or more, and the mixing ratio is, for example, 1:9 to 9 by weight in the case of two types of polymers. : Can be used within the range of 1.

In the photosensitive lithographic printing plate that does not require dampening water of the present invention, the two or more polymers having Tg different from each other by at least 5° C. are preferably contained in the primer layer as a whole with a Tg of 40 to 99
It may be contained in a range of % by weight.

In addition, the ethylenically unsaturated monomer or oligomer used in the present invention is a compound having a boiling point of 100°C or higher under normal pressure and containing two or more polymerizable terminal ethylene groups, and various known ones can be used. can. For example, unsaturated carboxylic acids, esters of unsaturated carboxylic acids and aliphatic polyhydroxy compounds, esters of unsaturated carboxylic acids and aromatic polyhydroxy compounds, unsaturated carboxylic acids and polyhydric carboxylic acids, and the aforementioned aliphatic polyhydroxy compounds. hydroxy compound,
Examples include esters obtained by esterification reactions with polyhydric hydroxy compounds such as aromatic polyhydroxy compounds, and are specifically described in JP-A-59-71048, such as diethylene glycol di(meth) Acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol triacrylate, hydroquinone di(meth)acrylate, pyrogallol triacrylate, 2,2'-bis(4-acryloxy-jethoxyphenyl) ) Propane, etc.

Other examples include (meth)acrylamide, hexamethylenebis(meth)acrylamide, etc.
Examples include acrylamides, vinyl urethane compounds, and epoxy (meth)acrylates.

In the present invention, ■ in the primer layer of the ethylenically unsaturated monomer or oligomer is 10 to 90% by weight.
and preferably 20 to 80% by weight.

Further, as the photopolymerization initiator, conventionally known ones can be used, and for example, benzoin, benzoin alkyl ether, benzophenone, anthraquinone, benzyl, Michler's ketone, a complex system of hiimidazole and Michler's ketone, etc. can all be suitably used.

The amount of the photopolymerization initiator in the primer layer is 01 to 20% by weight, preferably 02 to 10% by weight.

In the photosensitive lithographic printing plate that does not require dampening water of the present invention, the primer layer may further contain a silane coupling agent containing an amino group or an epoxy group.

In the present invention, specifically, the following silane coupling agents and the like are used.

(1) Amino group-containing silane coupling agent H,N(CH
2) JH(CHz)sSi(OCHs)a (TS
L-8340)NH[(CH2)sSi(OCHs)s
Ko2 (TSL-8208)H2
NCHtCHJ[(CHi)ssi(OCHs)a]2
(TSL-8214)H2N(CH2)ssi(OCJ
s)s (TSL-8331) (2) Epoxy group-containing silane coupling agent (CH2-CH-CHi)J(CHz)3si(OCH
s)3(TSL-8223)CH2-CIICHJ[(
CH2)asi(OCHs)a]z (TSL-82
28) The above amino group- or epoxy group-containing silane coupling agent is preferably used in the primer layer at a concentration of 01 to 30% heavy toxicity.
It is preferably contained in an amount of 05 to 20% by weight.

In the present invention, in addition to the above components, the primer layer may contain other fillers or antihalation agents, colorants such as dyes and pigments, coating improvers, plasticizers, stabilizers,
It may also contain an oil sensitizing agent or the like in an amount not exceeding 10% by weight. It is also possible to use in combination various conventionally known polymers, such as polyamide and polyurethane, which are usually used in the brimer layer.

Examples of dyes that can be included in the primer layer include Victoria Pure Blue BOH.

Oil blue #603, oil pink #312, patent pure blue, crystal violet, leuco crystal violet, brilliant green, ethyl violet, methyl green, erythrosin B1 basic fuchsin, malachite green, leucomalachite green, m-cresol purple, cresol red, Xylenol Blue, Rhodamine B1 Auramine, 4
Examples include triphenylmethane-based, diphenylmethane-based, oxazine-based, xanthine-based, iminonaphthoquinone-based, azomethine-based, and anthraquinone-based dyes represented by -p-diethylaminophenylimino naphthoquinone, cyano-p-diethylaminophenyl acetanilide, and the like.

Examples of coating properties improvers include alkyl ethers (e.g., ethyl cellulose, methyl cellulose), fluorine-based surfactants, and nonionic surfactants (e.g., [Pluronic L-64J (manufactured by Layaka Co., Ltd.), rFC-43].
0J (manufactured by 3M), etc.

Examples of plasticizers for imparting flexibility and abrasion resistance to coating films include butylphthalyl, polyethylene glycol,
Examples include tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrafurfuryl oleate, oligomers of acrylic acid or methacrylic acid, etc. .

In addition, in order to improve the printing ink adhesion of images, various additives having hydrophobic groups are used, such as p-octylphenol/formalin novolac resin, p-t-butylphenol/formalin novolac resin, p-t-butylphenol/benzaldehyde resin. , a modified novolac resin such as a rosin-modified novolak resin, or an 0-naphthoquinonediazide sulfonic acid ester (esterification rate of OH group: 20 to 70 mol %) of these modified novolak resins can be used.

When the above-mentioned brimer composition contains a pigment, it can be prepared using a known dispersion method (
After dispersing with SGI, homogenizer, etc.), it is filtered. The primer layer of the present invention is formed by applying the dispersion onto a support, drying it, and then photocuring it.

For photocuring, a known light source such as a mercury lamp, xenon lamp, or natural light is used, and the amount of exposure (
Usually, for example, 50mJ/crr? 5 J/crrr).

Further, the above-mentioned curing is desirably carried out at least before the coating of the photosensitive layer is completed, and more preferably immediately after coating.

In the present invention, the thickness of the primer layer is 1 mg/dn (
It is preferably ~500 mg/drrf, more preferably 3 mg/drrr ~300 mg/drrf
It is.

In the present invention, a photosensitive layer is provided on the primer layer, but any photosensitive layer that can be used in the present invention can be used as long as its solubility in a developer changes before and after exposure. be.

Specifically, for example, 0-quinonediazide compound, 0-
Examples include a photo-insolubilizable photosensitive layer containing a nitrobenzyl carbinol ester compound, a diazo compound, a compound having an addition-polymerizable vinyl group, and the like.

The above-mentioned 0-quinonediazide compounds are compounds having at least one 0-quinonediazide group, preferably an 0-benzoquinonediazide group or an 0-naphthoquinonediazide group, and include known compounds of various structures, such as those described in J. Kosar's book Rai I Sensitivity Systems” (
It includes compounds described in detail on pages 339 to 353 (published by John Wiley & Sams, Inc., 1965).

For example, various hydroxyl compounds and benzoquinone-1
, 2-diazide sulfonic acid, naphthoquinone-1,2-diazide sulfonic acid, and the like. Examples of the hydroxyl compound used include condensation resins of phenols such as phenol, cresol and pyrogallol and carbonyl group-containing compounds such as formaldehyde, benzaldehyde and acetone, particularly resins obtained by condensation in the presence of an acidic catalyst. It will be done.

As a photosensitive layer containing a diazo compound, JP-A-1-104
Preferably, the prestige layer shown in Japanese Patent No. 286 has a diazo resin and a (meth)acrylic acid ester having a hydroxyl group or an amide-containing polymer as essential components.

In the case of such a photosensitive layer, the proportion of the diazo resin in the photosensitive layer is preferably 1 to 90% by weight, more preferably 3% by weight.
~60% by weight.

Examples of compounds having an addition polymerizable vinyl group include compounds having a boiling point of 100° C. or higher under normal pressure and having two or more polymerizable terminal ethylene groups, such as unsaturated carboxylic acids,
Esters of unsaturated carboxylic acids and aliphatic polyhydroxy compounds, esters of unsaturated carboxylic acids and aromatic polyhydroxy compounds, unsaturated carboxylic acids and polycarboxylic acids, and the aforementioned aliphatic polyhydroxy compounds, aromatic polyhydroxy Examples include esters obtained by an esterification reaction with a polyhydric hydroxy compound, and are specifically described in JP-A-59-71048 and the like.

In the present invention, all of the above-mentioned photosensitive layers can be used, but a photosensitive layer containing a diazo resin is preferred from the viewpoint of adhesion to the primer layer.

Further, in the present invention, in addition to the above-mentioned materials, dyes, pigments, known exposure visible image agents, coating property improvers, etc. may be added to the photosensitive layer to improve the developable visible image property.
Exposure visibility and coating properties can be improved.

Further, in the present invention, it is preferable that the photosensitive layer contains a hydroxyl group-containing polymer. As such a hydroxyl group-containing polymer, the same polymers as those used in the primer layer described above can be used.

Is the thickness of the photosensitive layer 0.1mg/drr? ~30mg/
drrr is preferred, 0.5mg/dm' to fOmg
/drn' is more preferred.

In the present invention, a silicone rubber layer is further provided on the photosensitive layer, and the silicone rubber used in the silicone rubber layer is preferably linear or crosslinked organopolysiloxane. The organopolysiloxane has a molecular weight of about 10 to about 100,
At room temperature, it is suitably cross-linked in the form of a liquid, wax, or rice cake. The organopolysiloxanes are classified into condensed type and addition type depending on the method of crosslinking.

In the condensed type, crosslinking is performed by a condensation reaction, and water, alcohol, organic acid, etc. are released by the reaction. Particularly useful condensation type silicone rubbers include a mixture of a linear organopolysiloxane having hydroxyl groups at both ends or a part of the main chain and a silicone crosslinking agent, or one in which the hydroxyl groups are reacted with a silicone crosslinking agent. In either case, adding a condensation catalyst is advantageous in terms of crosslinking speed.

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

In the formula, R1 and R2 are alkyl, aryl, alkenyl, or a combination thereof, each of which may have a substituent such as a cyano group, a halogen atom, or a hydroxyl group, and a methyl group, a phenyl group, a vinyl group, or a trifluoropropyl group. Preferably, methyl group is particularly preferable.

The above-mentioned silicone crosslinking agents include the so-called acetic acid-removal type, oxime-elimination type, alcohol-elimination type, deamination type, dehydration type, and those having a functional group represented by -OH (in the formula, R and R' are alkyl groups). Examples include condensed silicone crosslinking agents such as molds. Examples of such crosslinking agents include tetraacetoxysilane, methyltriacetoxysilane, ethyltriacetoxysilane, phenyltriacetoxysilane, dimethyldiacetoxysilane,
Diethyldiacetoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, methyltris(acetoneoxime)silane, methyltri(N-methyl,
Examples include N-acetylamino)silane, vinyltri(methylethylketoxime)silane, methyltri(methylethylketoxime)silane or its oligomer, and reactive silane compounds having an isocyanurate group.

All of these crosslinking agents are organopolysiloxane 10
The amount is preferably in the range of 0.5 to 30 parts by weight relative to 0 parts by weight.

Examples of the condensation catalyst include dibutyltin dilaurate, dibutyltin acetate, dibutyltinmaleate, and the like.

Addition type refers to unsaturated groups in the main body, such as vinyl groups (-,
CH=CH2) is crosslinked by the addition of a hydrogen group in a crosslinking agent.

Specifically, examples include vinyl group-containing organopolysiloxanes, hydrogenated organopolysiloxanes, and the like mixed with platinum-based catalysts (for example, chloroplatinic acid).

The organopolysiloxane has repeating units similar to those of the condensed type in the main chain.

For the silicone rubber layer in the present invention, either or both of condensation type and addition type silicone rubber can be used.

It is also possible to use condensed and addition type organopolysiloxanes having hydroxyl groups, unsaturated groups, etc. in one organopolysiloxane.

Among the commercial products available as the silicone rubber according to the present invention, a preferable example is "KS-705FJ" manufactured by Shin-Etsu.
, rKE-41ko, rKE-42J
, rKE-44J, manufactured by Toshiba Silicone (manufactured by Toshiba Silicone) r
YE5505J.

rY F 3057J, Toshi Silicone Co., Ltd. rSH
-781J, rPRX-305J, rsH
Condensation type silicone rubber such as -237J and rK manufactured by Shin-Etsu
S-837J.

rKE-103J, rKE-106J, r
KE-1300J.

Toshiba Silicone (manufactured) "TSE-3032J, rR
TU-BJ, Toshi Silicone (manufactured by) r S H-
Examples include addition type silicone rubber such as 9555J.

Furthermore, for the purpose of improving the strength of silicone rubber, inorganic fillers such as silica, titanium oxide, and aluminum oxide may be added, and silica is particularly preferably used.

From the viewpoint of dispersibility or dispersion stability, such fillers preferably have an average particle diameter of 500 nm or less.

In the present invention, the thickness of the silicone rubber layer is preferably as thin as possible from the point of view of image quality and developability, but on the other hand, a certain degree of thickness is required from the point of view of printing durability and printing stains. dbo~50mg/drrf is preferable, 5m
g/d i to 30 mg/d po is more preferable.

Further, the photosensitive lithographic printing plate that does not require dampening water of the present invention may have a protective layer on the silicone rubber layer, and a method for providing the protective layer is to laminate a polypropylene film or the like as described in Japanese Patent Publication No. 61-614. Method and JP-A-61-27
A method of coating a high molecular weight polymer described in No. 545 is known.

As the substrate used in the present invention, any substrate can be used as long as it has the flexibility to be set in a normal lithographic printing machine and can withstand the load applied during printing, and there are no particular restrictions on the substrate including the layer structure. . For example, paper such as coated paper, metal plate such as aluminum plate, or plastic film such as polyethylene terephthalate can be cited as examples, but aluminum plate or a composite material of aluminum foil and other materials is preferable and has a long printing life. From the viewpoint of properties, aluminum plates are particularly preferred.

In the present invention, the photosensitive lithographic printing plate prepared as described above is imagewise exposed, developed with a developer to dissolve the photosensitive layer, and removed together with the silicone rubber layer thereon, resulting in the primer layer forming an image area. Upon exposure, a dampening water-less lithographic printing plate is formed.

In this case, it is preferable to dye the image area with a dye during or after development.

For such dyeing, a dyeing solution containing water as a main component and a dye as an essential component is used.

Preferred dyes include specifically the following acidic dyes and basic dyes.

Acidic dyes include nitro dyes such as Naphthol Yellow (C,1, Acid Yellow 1), monoazo dyes such as Fast Red A (CI Acid Red 88), disazo dyes such as Naphthol Blue Black (C, 1, acid black 1), nitroso dyes, such as naphthol green B (C,! acid green 1), triphenylmethane dyes, such as patent blue (C, I, acid blue 3), brilliant milling. Green B (C,I Acid Green 9), xanthine dyes such as Sulpho-Rhodamina B (C,1, Acid Red 52), anthraquinone dyes such as Alizarin Direct° Blue A2G (C,I Acid Blue 40) , azine dye,
Examples include Woolfast Blue GL (C, 1, Acid Blue 102), quinoline dyes such as Quinoline Yellow (C, R, Acid Yellow 3), and preferred basic dyes include: , include the following:

Diphenylmethane dyes, such as Auramine O (C,I Basic Yellow 2), triphenylmethane dyes, such as Magenta (C,1, Basic Violet 14)
), methyl violet (C,1 Basic Violet 1), malachite green (C,1, Basic Green 4), thiazole dyes such as Thioflavin T (C,I Basic Yellow 1), xanthine dyes such as rhodamine B (C,1, Basic Violet 10), oxazine dyes such as Neil Blue BX (CI Basic Blue 12), thiazine dyes such as Methylene Blue B (C,1, Basic Blue 9), azine dyes, For example, safranin T (C
, 1, Basic Red 2), azo dyes, such as Bismarck Brown G (C, !Basic Brown 1)
), indocyanine dyes, e.g. astraflaxin F
F (C, 1, Basic Red 12), etc. In the present invention, triphenylmethane dyes are particularly preferably used. These dyes are used in an aqueous solution, and the concentration thereof is preferably 0.1 g/ffi to 10 g/ρ.

In the present invention, when dyeing is performed using these dye aqueous solutions, the concentration thereof is 10°C to 50°C. In addition, the dyeing method is
This is carried out by immersing the developed printing plate in a dye solution, or by coating or shower-spraying an aqueous dye solution onto the printing plate. A dyeing aid can be added to this aqueous dye solution as required.

As dyeing aids, water-soluble organic solvents, surfactants, and the like are used to facilitate dyeing of the brimer layer.

As the organic solvent, ethanol, tulfite, benzyl alcohol, etc. are preferably used, and as the surfactant, nonionic surfactants are preferred from the viewpoint of foaming properties.

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

The developer used in the development process includes water, the following polar solvents, alkaline compounds such as amines, surfactants, aliphatic hydrocarbons (hexane, heptane, "Isopar E,"
H, GJ (trade name of aliphatic hydrocarbons manufactured by Esso Chemical) or gasoline, kerosene, etc.), aromatic hydrocarbons (
Toluene, xylene, etc.) or halogenated hydrocarbons (triclene, etc.) are added as necessary.

11 Alcohols (methanol, ethanol, β-anilinoethanol, propylene glycol, etc.) Ethers (
Methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carpitol, ethyl carpitol, butyl carpitol, dioxane, etc.) Ketones (acetone, methyl ethyl ketone, etc.) Esters (ethyl acetate, methyl cellosolve acetate, cellosolve acetate, carpitol acetate, etc.) Development This can be carried out by various known methods, such as rubbing with a developing pad containing the developer as described above, or pouring the developer onto the printing plate and then rubbing with a developing brush.

[Examples] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

(Synthesis of Diazo Resin-1) 14.5 g of p-diazodiphenylamine sulfate was dissolved in 40.9 g of concentrated sulfuric acid under water cooling. 1.0 in this reaction solution
g of rose formaldehyde was slowly added dropwise so that the reaction temperature did not exceed 10°C. Then, stirring was continued under water cooling for 2 hours.
was added dropwise to ethanol, and the resulting precipitate was filtered. After washing with ethanol, this 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 this solution. The resulting precipitate was filtered, washed with ethanol, and dissolved in f50J pure water. Add 8g to this liquid
A cold concentrated aqueous solution of ammonium hexafluorophosphate was added. The resulting precipitate was collected by filtration and washed with water, and then
Diazo resin-1 was obtained by drying at °C for a day and night.

The styrene-equivalent weight average molecular weight (Mw
) was 1500, and the number average molecular weight was 500.

Example '1 On a smooth aluminum plate having a thickness of 0.24 mm and degreased in a conventional manner, the following primer layer composition was applied at 60°C using a pourer and dried at 100°C for 2 minutes to form a primer layer. The dry film thickness was 130 mg/d.

The brimer layer composition was dispersed using a high-pressure valve homogenizer.

(Brimer layer composition) (1) Binder resin (see Table 1) 100 parts (2) Pentaerythritol triacrylate 60 parts (3) DA-314 (Nagase Kasei ■) 20 parts (4) D
ETX 3 parts (5) EPA 3 parts (6) KET-YELLOW402 (Dainippon Ink 11 parts color pigment) 8 parts (7)
Zinc oxide (average particle size: 012μ) 20 parts (8) Silane coupling agent (see Table 1) (9) Methyl lactate 600 parts After coating and drying, Unicure (manufactured by Ushio Inc.) - 160 W, 4 m/min exposure. I did this.

Next, the following photosensitive composition was applied onto the primer layer and dried at 80° C. for 2 minutes to form a photosensitive layer with a thickness of 0.3 μm.

(Photosensitive composition) (1) Diazo resin - 1100 parts (2) 2-hydroxyethyl methacrylate, N-(4
Copolymerization #rJJ resin (Mw
=4.2
It was coated so that it was rr, and dried at 100°C for 4 minutes.

(Silicone rubber layer composition) (1) 100 parts (2
) The following reactive silane compound (3) 0.8 parts of dibutyltin dilaurate (4) 900 parts of Isopar E (manufactured by Esso Chemical) Next, a 6μ thick polypropylene film was laminated on the silicone rubber layer, and a dampening solution was applied. Unwanted photosensitive lithographic printing plate samples 1 to 7 were obtained.

The scratch resistance, adhesion and image quality of each of the obtained samples were measured by the following methods. The results are shown in Table 1.

Scratch resistance: After exposing and developing the entire surface of the sample under the following conditions, the plate surface (
A scratch is made on the non-printed area) using a sapphire needle with a diameter of 0.2 mm using a continuous load type scratch strength tester Type-HEICON 18 manufactured by Shinto Kagaku ■, and the maximum load that does not cause scratches is defined as the scratch resistance.

Adhesion: The entire surface of the sample was exposed and developed under the following conditions.

The obtained plate was bent at 90°, and the adhesion to the substrate was visually judged (5-level evaluation).

5: No change to 1: Completely peeled off at the bent part Image quality: A 175/l/1-nch dot chart was placed on the sample, and after exposure, development, and dyeing, the reproducibility was visually judged.

In addition, after vacuum-adhering a positive film to the top surface of each sample, a metal halide lamp was used as a light source and a 400 mJ
/crrr exposure, and then immersed in the following developer-1 for 1 minute, the surface of the plate material was rubbed with a pad impregnated with the developer to remove the unexposed portions of the silicone rubber layer and photosensitive layer. Got the print version.

(Developer-1) β-anilinoethanol 0.5 parts Propylene glycol 1.0 parts p-t
ert-butylbenzoic acid 10 parts Potassium hydroxide 1.0 part Polyoxyethylene lauryl ether 0.1 part Potassium sulfite
2.0 parts potassium metasilicate
3.0 parts water
91 copies Each of the above printing plates was further dyed by lightly rubbing the plate surface with a cloth containing a dyeing solution having the composition shown below and then washing with water to obtain a developed visible image.

(Staining solution) 20 parts Tulfit (manufactured by Kuraray Sobren Chemical, solvent) 0.5 parts Residor T W-0120 (surfactant, manufactured by Kao) 0.5 parts Benzyl alcohol 5.0 parts Victoria Pure Blue BOH 1.0 parts water
100 parts ml, binder resin acrylic-1 HEMA/MMA=45155. Mw=4.5X10'
.

T g=58℃ Acrylic-2 HEMA/MMA=34766, Mw=4.3X10'
.

T g = 48°C Acrylic-3)-I E M'A/MMA/B A =50/40/
10゜Mw = 4.2X 10', T g = 46
℃ Acrylic-4 HEMA/MMA/EA=50/15/35゜Mw=4
．． 0X10', Tg=36°C Acrylic-5 HEMA/MMA=42158. Mw=4.5X10'
.

Tg = 55°C As is clear from Table 1, the samples of the present invention in which two types of polymers with Tg different by 56 parts or more are used together are excellent in all aspects of adhesion, image quality, storage stability over time, and scratch resistance. .

Example 2 In the preparation of sample No. 1 of Example 1, the binder resin of the primer layer was polyester urethane r U manufactured by Toyobo Co., Ltd.
R-8300J (T g = 20℃), rUR-
Samples of photosensitive lithographic printing plates that do not require dampening water were obtained in the same manner except that the sample was changed to 8700J (-20°C) and 50 parts each. The obtained sample was evaluated in the same manner as in Example 1, and the image quality,
Both adhesion and scratch resistance were good.

[Effects of the Invention] As explained in detail above, the present invention provides a moisture-retaining material that has excellent adhesion to a primer layer even when used as a support without subjecting an aluminum plate to activation treatment, and has excellent storage stability over time. A water-free photosensitive lithographic printing plate can be provided. Further, it is possible to provide a photosensitive lithographic printing plate that does not require dampening water and has excellent photocurability of the primer and excellent scratch resistance.

Patent applicant Mitsubishi Kasei Corporation (1 other person) Agent
Patent attorney Ichinose Miyao 1 stomach, 1. ．． ．． -: J:・-to

Claims (1)

[Claims] In a photosensitive lithographic printing plate that does not require dampening water and has at least a primer layer, a photosensitive layer, and a silicone rubber layer in this order from the support side on a support, the primer layer has at least a) a glass transition temperature (Tg) of at least 5; C) contains two or more types of polymers different in temperature, b) an ethylenically unsaturated monomer or oligomer, and c) a photopolymerization initiator,
A photosensitive lithographic printing plate that does not require dampening water and is photocured before coating the photosensitive layer.