JPH0456858A - Developer for dampening waterless photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To suppress smells, formability, sludge generation, etc. by incorporating water, alkali and a specific org. solvent having the specific solubility in water into the above developer. CONSTITUTION:At least the water, alkali and the org. solvent having >=20wt.% solubility in water are incorporated into the developer used for the dampening waterless photosensitive planographic printing plate formed with the photosensitive layer which contains at least a hydroxyl group-contg. polymer and diazo resin. The developer contg. preferably >=30wt.% more preferably >=50wt.% water, preferably 0.5 to 30wt.%, more particularly preferably 2 to 20wt.% alkali and preferably <=20wt.%, more particularly preferably <=10wt.% org. solvent having >=20wt.% solubility in water is used. The smells are substantially eliminated and the generation of the sludge is lessened. The foaming is thus suppressed.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a developer for photosensitive lithographic printing plates that does not require dampening water;
Specifically, the present invention relates to a developer used in a photosensitive lithographic printing plate that does not require dampening water and has a diazo-based photosensitive layer.

[Prior art] Conventionally, in planographic printing, it has been necessary to perform printing by making use of the lipophilicity of the imaged area and the hydrophilicity of the non-imaged area, with a delicate balance of water and ink, which requires 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 particular, the present inventors proposed in Japanese Patent Application No. 1-104286 a photosensitive lithographic printing plate that does not require dampening water and contains a hydroxyl group-containing polymer and a diazo resin in the photosensitive layer.

As a developer used for developing such a lithographic printing plate, conventionally, for example, Japanese Patent Application Laid-Open No. 61275759 has been used.
A developer comprising water, a surfactant and an organic solvent as described in JP-A-1-159644, a developer comprising water, a surfactant and 20% or less of an organic solvent as described in JP-A No. 1-257847 A developing solution containing water, a surfactant, an organic solvent, and a basic compound is known as described in the publication.

[Problems to be Solved by the Invention] However, when a lithographic printing plate as described in the above-mentioned Japanese Patent Application No. 1-104286 is developed with various developers, there is only a difference in odor and foaming properties depending on the developer. smooth,
Solubility in developer, scratch resistance, which causes sludge generation, etc.
It has become clear that image quality, stainability, etc. are different.

In particular, the developing solutions described in the above-mentioned publications are inferior in foaming properties, image quality, dyeing properties, etc., and no developing solution satisfying all of the above characteristics has been obtained.

Therefore, an object of the present invention is to provide a developer for a photosensitive lithographic printing plate that has almost no odor, generates little sludge, and exhibits extremely low foaming, requiring no dampening water. Another object of the present invention is to provide a developer for photosensitive lithographic printing plates that does not require dampening water and provides excellent scratch resistance, image quality, and dyeability. A further object of the present invention is to provide a developer for photosensitive lithographic printing plates that does not require dampening water and can also be used to develop positive-working photosensitive lithographic printing plates.

[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 provide at least a photopolymerizable primer layer, a photosensitive layer, and a silicone rubber onto a substrate from the substrate side. A developer for use in a dampening water-free photosensitive lithographic printing plate having layers in this order and in which the photosensitive layer contains at least a hydroxyl group-containing polymer and a diazo resin, the developer having at least water, an alkali, and a solubility in water. 20% by weight or more of an organic solvent,
We have found that this can be achieved by providing a developer for photosensitive lithographic printing plates that does not require dampening water and is characterized by containing:

The present invention will be explained in more detail below.

The developer of the present invention contains at least water, an alkali, and an organic solvent having a solubility in water of 20% by weight or more, preferably 30% by weight or more, especially 50% by weight or more of water, and 0.5 to 30% by weight of alkali. % by weight, especially 2 to 20% by weight, and 20% by weight of an organic solvent with a solubility in water of 20% by weight or more.
The composition used is less than 10% by weight, especially less than 10% by weight.

Specifically, the organic solvent having a solubility in water of 20% by weight or more used in the developer of the present invention includes alcohols such as methanol, ethanol, propylene glycol, and β-anilinoethanol, methyl cellosolve, ethyl cellosolve, etc. Examples include cellosolves, acetone, and ketones such as methyl ethyl ketone.

In addition, alkaline agents include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, dibasic or tribasic sodium or ammonium phosphate, sodium metasilicate, sodium carbonate,
Inorganic alkaline agents such as ammonia, mono-, di- or trimethylamine, mono-, di- or triethylamine, mono- or diisofurobilamine, n-butylamine, mono-,
Examples include organic amine compounds such as di- or triethanolamine, mono-, di- or triisopropanolamine, ethyleneimine, and ethylenediimine.

Further, the developer of the present invention may contain components such as a dye, a surfactant, and an organic solvent, if necessary, within a range that does not impair the object of the present invention.

In the photosensitive lithographic printing plate that does not require dampening water and is used in the present invention, the primer layer contains a hydroxyl group-containing polymer, an ethylenically unsaturated monomer or oligomer, and a photopolymerization initiator.

As the hydroxyl group-containing polymer, esters or amides of alcoholic hydroxyl group-containing poly(meth)acrylic acid are preferably used.

In the present invention, when an acrylic compound and a methacrylic compound are referred to below, they will be written as "(meth)acrylic...".

Examples of polymers having alcoholic hydroxyl groups include 2-hydroxyethyl (meth)acrylate, N-(4
-Hydroxyethylphenyl)methacrylamide, hydroxymethyldiacetone(meth)acrylamide, and the like having structural units derived from monomers such as (meth)acrylamide and the like. In particular, polymers having structural units derived from 2-hydroxyethyl (meth)acrylate are preferred.

The alcoholic hydroxyl group-containing polymer may be a copolymer, and the copolymer monomers include (1) a monomer having an aromatic hydroxyl group, such as N-(4
-Hydroxyphenyl)(meth)acrylamide,○-
α, β of 1m-p-hydroxystyrene, o-1m-p-hydroxyphenyl-(meth)acrylate, (2) (meth)acrylic acid, maleic anhydride, etc.
-Unsaturated carboxylic acids, (3) methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (
meth)acrylate, amyl(meth)acrylate, hexyl(meth)acrylate, octyl(meth)acrylate, 2-chloroethyl acrylate, 2-hydroxyethyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, glycidyl(meth)acrylate acrylate, optionally substituted alkyl (meth)acrylate such as N-dimethylaminoethyl (meth)acrylate, (4) (meth)acrylamide, N-methylol (meth)acrylamide, N-ethylacrylamide, N-hexyl Optionally substituted (meth)acrylamides such as methacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl-N-phenylacrylamide, (5) ethyl Vinyl ethers such as vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether, etc. (6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, vinyl benzoate, etc. (7) Styrenes such as styrene, α-methylstyrene, and chloromethylstyrene; (8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone; (9) ethylene, propylene, and isobutylene. (10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, and the like. Particularly preferred is (3).

The hydroxyl group-containing upper group in the hydroxyl group-containing polymer is not particularly limited, but is preferably 5 to 100% by weight.
, particularly preferably 20 to 100% by weight.

The weight average molecular weight of the hydroxyl group-containing polymer of the present invention measured by gel permeation chromatography (GPC) is preferably 5,000 to 1,000,000 (in terms of styrene). If the value is lower than s, ooo, the coating solvent or developer of the photosensitive layer may be affected even after photocuring, and if the value is greater than 1,000,000, it is difficult to select a coating solvent.

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.

Moreover, as the ethylenically unsaturated monomer or oligomer, it is a compound having a boiling point of 100° C. or more under normal pressure and containing two or more polymerizable terminal ethylene groups, and various known ones can be used. 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. Examples include esters obtained by esterification reactions with polyhydric hydroxy compounds such as hydroxy compounds and aromatic polyhydroxy compounds. (meth)acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol triacrylate, hydroquinone di(meth)acrylate
Acrylate, pyrogallol triacrylate, 2.2
' -bis(4-acryloxy-jethoxyphenyl)
Examples include propane. In addition, ethylene bis (
Examples include (meth)acrylamides such as meth)acrylamide and hexamethylenebis(meth)acrylamide, vinyl urethane compounds, and epoxy(meth)acrylate.

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

Furthermore, as the photopolymerization initiator, any conventionally known initiator can be used, and for example, benzoin, hendiin alkyl ether, benzophenone, anthraquinone, benzyl, Michler's ketone, a complex system of biimidazole 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 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 various conventionally known polymers, such as polyamide and polyurethane, which are usually used in primer layers.

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 Tsushin, Malachite Green, Leucomalachite Green, m-Cresol Purple, Cresol Red , xylenol blue, rhodamine B1 auramine,
4-p-diethylaminophenylimino naphthoquinone,
Examples include triphenylmethane-based, diphenylmethane-based, oxazine-based, xanthine-based, iminonaphthoquinone-based, azomethine-based, and anthraquinone-based dyes represented by cyano-p-diethylaminophenylacetanilide.

Examples of coating properties improvers include alkyl ethers (e.g., ethyl cellulose 2, methyl cellulose), fluorine-based surfactants, nonionic surfactants (e.g., Pluronic L-64 (manufactured by Asahi Denka)), FC-430 ( manufactured by Sumitomo 3M).

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, such as p-octylphenol/formalin novolac resin, pt-butylphenol/formalin novolak resin, pt-butylphenol/benzaldehyde resin, are also used. , a modified novolak resin such as a rosin-modified novolak resin, or an O-naphthoquinonediazide sulfonic acid ester (esterification rate of OH group: 20 to 70 mol %) of these modified novolac resins can be added.

If the primer composition contains a pigment, the primer composition may be prepared using a known dispersion method (
After dispersing with a homogenizer (SG■, 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 (
This can be carried out by exposing to light (usually in the range of 50 mJ/cm to 5 J/cmI'', for example).

Further, it is desirable that the above-mentioned curing be performed at least in advance after the coating of the photosensitive layer is completed.

In the present invention, the thickness of the primer layer is 1 mg/di~
It is preferably 500 mg/di, more preferably 3 mg/di to 300 mg/drr? It is.

In the present invention, a photosensitive layer is provided on the primer layer, and in the present invention, a layer containing a diazo resin and a hydroxyl group-containing polymer is used as the photosensitive layer.

As the diazo resin, for example, Photographic Science and Engineering (Photo
, Sci, Eng,) Volume 17, Page 33 (197
3), U.S. Patent No. 2,063,631, U.S. Patent No. 2,67
Diazo compounds and active carbonyl compounds (e.g. formaldehyde, acetaldehyde, benzaldehyde, etc.) whose production methods are described in the specifications of No. 9,498, No. 3.050,502, JP-A-59-78340, etc. Diazo resin obtained by condensing the above in an acidic medium such as sulfuric acid, phosphoric acid, or hydrochloric acid,
It is possible to use a diazo resin obtained by subjecting a diazo compound and a diphenyl ether derivative to a condensation reaction, the manufacturing method of which is described in Publication No. 1.

The counter anion of the diazo resin used in the present invention is
It contains an anion that forms a stable salt with the diazo resin and makes the resin soluble in organic solvents.

These include organic carboxylic acids such as decanoic acid and benzoic acid;
Contains organic phosphoric acids and sulfonic acids such as phenyl phosphoric acid,
Typical examples include methanesulfonic acid, chloroethanesulfonic acid, dodecanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, mesitylenesulfonic acid and anthraquinonesulfonic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, hydroquinone Sulfonic acid, 4-acetylbenzenesulfonic acid, dimethyl-5
Aliphatic and aromatic sulfonic acids such as sulfoisophthalate, hydroxyl groups such as 2.2', 4.4'-tetrahydroxybenzophenone, 1,2.3-trihydroxybenzophenone, 2.2', 4-trihydroxybenzophenone, etc. Containing aromatic compounds, halogenated Lewis acids such as hexafluorophosphoric acid and tetrafluoroboric acid, C2O4,
Examples include, but are not limited to, perhalogen acids such as IO4. The coupled product with β-naphthol was analyzed using gel permeation chromatography (GPC).
The weight average molecular weight measured in ) is preferably in the range of 200 to 10,000 (in terms of styrene), more preferably in the range of 500 to 5,000.

The proportion of the diazo resin in the photosensitive layer is preferably 1 to 90% by weight, more preferably 3 to 60% by weight.

The hydroxyl group-containing polymer contained in the photosensitive layer may be the same as the hydroxyl group-containing polymer used in the primer layer as described above.

Furthermore, 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 as needed to improve the development visible image properties and exposure visible image properties. It is also possible to improve the coating properties.

The thickness of the photosensitive layer is 0.1mg/di to 30mg/d
i or preferably 0.5mg/di ~ 10mg/
di is more preferable.

In the present invention, a silicone rubber layer is further provided on the photosensitive layer, or the silicone rubber used in the silicone rubber layer is preferably linear or crosslinked organopolysiloxane. The organopolysiloxane usually has a molecular weight of 100,000 to several hundred thousand,
At room temperature, it is suitably cross-linked in the form of a liquid, wax, or rice cake. The organopolysiloxanes are classified into fused ring type and addition type depending on the crosslinking method.

The fused ring is crosslinked by a condensation reaction, and water, alcohol, organic acid, etc. are released by the reaction. Particularly useful condensed ring 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, the addition of a condensation catalyst is advantageous in terms of crosslinking speed.

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

-(-S i -0← 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 and a trifluoropropyl group are preferred, and a methyl group is particularly preferred.

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 fused ring 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, dibutyltin maleate, and the like.

Addition type refers to an unsaturated group in the main body, such as a vinyl group (-C
It refers to something that is crosslinked by the addition of a hydrogen group in a crosslinking agent to H=CH,).

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

The organopolysiloxane has a repeating unit similar to the above-mentioned condensed ring in the main chain.

For the silicone rubber layer, it is possible to use either or both of a condensed ring type silicone rubber and an addition type silicone rubber.

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

Among the commercially available silicone rubbers used in the present invention, preferred examples include KS-705F manufactured by Shin-Etsu,
KE-41, 42, 44, manufactured by Toshiba Silicone (manufactured by Toshiba Silicone)
YE5505. YF3057, manufactured by Toshi Silicone (manufactured by Toshi Silicone)
Condensed ring silicone rubber such as 5H-781, PRX-305, 5H-237 and Shin-Etsu K S-837°K
Additive silicone rubbers include E-103, KE-106, KE-1300, TSE-3032, RTU-B manufactured by Toshiba Silicone, and SH-9555 manufactured by Toshi Silicone.

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. d resistance to 50 mg/d resistance is preferable, and 5 mg/d resistance is preferable.
/dm ~30mg/drr? 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. Exposure and a waterless lithography 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, R, Acid Yellow 1), monoazo dyes, such as Fast Red A (C.

■, Acid Red 88), disazo dyes such as naphthol blue black (C,1, acid black 1), nitroso dyes such as naphthol green B
(C,1, Acid Green 1), triphenylmethane dyes such as Patent Blue (C,1, Acid Blue 3), Brilliant Milling Green B
(C, 1, acid green 9), xanthine dye,
For example, sulforhodamina B (C,1, acid red 52), anthraquinone dyes, such as alizarin.
Direct Blue A2G (C, I Acid Blue 4
0), azine dyes such as Woolfast Blue G
L (C, 1, Acid Blue 102), quinoline dyes, such as Quinoline Yellow (C, I Acid Yellow 3), etc., and preferable basic dyes include, specifically, the following: It will be done.

Diphenylmethane dyes, such as auramine O (C,1,
Basic Yellow 2), triphenylmethane dye,
For example, magenta (C, 1, basic violet 1
4), Methyl Violet (C,I.

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 (C.

■, Basic Blue 12), thiazine dyes, such as methylene blue B (C, I Basic Blue 9)
, azine dyes such as Safranine T (C,1, Basic Red 2), azo dyes such as Bismary Brown G (C,1, Basic Brown 1), indocyanine dyes such as Astrafracin FF (C, 1
, Basic Red12) etc. In the present invention, triphenylmethane dyes are particularly preferably used. These dyes are used in aqueous solution, the concentration of which is 0.1 g
,,'x~10g/1 is preferable.

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 the dyeing aid, a water-soluble organic solvent, a surfactant, etc. are used in order to facilitate dyeing of the primer 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 mm or more and visible light may be used, but carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes, etc. are particularly preferred.

Development can be carried out by various known methods, such as rubbing with a developing pad containing a developer as described above, or pouring a 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 the 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. This reaction solution contains 1, O
g of paraformaldehyde was slowly added dropwise so that the reaction temperature did not exceed 10°C. Thereafter, stirring was continued for 2 hours under water cooling. This reaction mixture was added dropwise to 500 ml of ethanol under water cooling, and the resulting precipitate was filtered. After washing with ethanol, this precipitate was dissolved in 100 ml (l) of pure water, and a cold concentrated aqueous solution containing 6.8 g of zinc chloride was added to this solution. After filtering the formed precipitate, it was washed with ethanol. , this was dissolved in 150 m, 9 pure water.In this solution,
A cold concentrated aqueous solution of 8 g of ammonium hexafluorophosphate was added. After filtering the resulting precipitate and washing with water,
Diazo resin-1 was obtained by drying at 30°C for one day.

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

Example-1 The following primer layer composition was applied at 60°C using a whirler on a chemically treated aluminum substrate (manufactured by Mitsubishi Aluminum) with a thickness of 0.24mm, and dried at 100°C for 2 minutes to form a primer layer. Established. Dry film thickness is 130mg/a r
r? Met.

The primer layer composition was dispersed using a high-pressure bulb homogenizer.

(Primer layer composition) (1) Copolymer resin of 2-hydroxyethyl methacrylate and methyl methacrylate in a molar ratio of 34,766 (Mw=
4. OX to') 100 parts (2) Pentaerythritol triacrylate 60 parts (3) DA-314 (Nagase Kasei ■) 20 parts (4) D
ETX (5) EPA 3 parts (6) KET-YELLOW402 (yellow pigment manufactured by Inu Nippon Ink ■) 8 parts (7) Zinc oxide (average particle size: 0.12μ) 20 parts (8) T S
L 8331 (H2N(CH2)3si(OEt
) s) 10 parts (9) Methyl lactate 600 parts After coating and drying, Unicure (manufactured by Ushio Denki ■) -160W,
Exposure was carried out at 4 m/min.

Next, a photosensitive composition having the composition shown below was coated on the primer layer and dried at 80° C. for 2 minutes to form a photosensitive layer having a thickness of 03 μm.

(Photosensitive composition) (1) Diazo resin - 1100 parts (2) 2-hydroxyethyl methacrylate, N-(4
Copolymer resin-2 (Mw=
4.2X 10') 100 parts (3) Orange 8 parts (4) Methyl lactate 900 parts Next, the following silicone rubber composition was applied to the photosensitive layer to a thickness of 2.
It was coated at a concentration of 0 g/m and dried at 100° C. for 4 minutes.

(Silicone rubber layer composition) (1) 100 parts (2) of dimethylpolysiloxane having hydroxyl groups at both ends (molecule j152,000)
The following reactive silane compound (3) dibutyltin dilaurate 0.8 part (4
) Isopar E (manufactured by Esso Chemical) 900 parts Next, a single-sided matted polypropylene film having a thickness of 6 μm was laminated on the silicone rubber layer to obtain a photosensitive lithographic printing plate sample that did not require dampening water.

After vacuum-adhering a positive film to the top surface of the above plate material, a metal halide lamp was used as a light source to produce 400 mJ.
/Cm exposure. Next, after being immersed for 1 minute in each of the developers I to ■ shown in Table 1, the surface of the plate material was rubbed with a pad impregnated with the developer to remove the silicone rubber layer and photosensitive layer in the unexposed areas. .

Each of the obtained printing plate samples was examined for scratch resistance and dyeability using the following method.

Scratch resistance: Immediately after development, the non-image area of the sample was tested using a continuously weighted scratch strength tester Heidon 18 manufactured by Shinto Kagaku ■.
Using a sapphire needle with a diameter of 0.2 mm, the load at which scratches began was evaluated.

Dyeability: After lightly rubbing the image area of the printing plate with a cloth containing a dyeing liquid having the composition shown below, the cloth was washed with water and the degree of dyeing was visually evaluated.

(Staining liquid) Tsurfit (manufactured by Kuraray Soprene Chemical ■, solvent) 20 parts Residor T W-0120 (manufactured by Kao ■, surfactant) 0.5 parts Benzyl alcohol 5.0 parts Victoria Pure Blue B OH 1.0 parts water
100 copies Each photosensitive lithographic printing plate sample was also evaluated for sensitivity and image reproducibility using the following method.

After a step table lamp was vacuum-adhered to the upper surface of the sensitive second plate material, it was exposed to light at 400 mJ/cm using a metal halide lamp as a light source. The sample was developed and dyed as described above, and the maximum number of dyed steps was defined as the sensitivity.

Image reproducibility After the Ugra chart was vacuum-adhered to the upper surface of the second plate material, it was exposed to light at 400 mJ/cm using a metal noride lamp as a light source. Develop as above,
The area where the halftone dots are reproduced after dyeing was defined as the image reproducibility.

The above results are shown in Table 1.

Furthermore, each of the developing solutions (1) to (2) was evaluated for odor, foaming property, and sludge generation using the following methods. The results are shown in Table 1.

Foaming property: Each developer was vigorously stirred and the degree of foaming was evaluated.

Sludge generation: A photosensitive layer corresponding to 50 durability of a dampening water-sensitive lithographic printing plate sample was dissolved in the developer per 12 developer solutions, and the degree of sludge generation was evaluated.

*1; In the composition, (*2; New Cool B4SN:) indicates mm% in the developer *3; Stainability ○; Very good degree of staining @; Slightly poor degree of stainability ×; Example not stained. 2 The non-printing area of the plate obtained in Example-1 was tested using a continuous load type scratch strength tester Heidon 18 manufactured by Niina Kagaku ■ at a load of 50 g using a sapphire needle with a diameter of 0.2 mm. After making the wound, the dampening water supply device was removed.

At Heidel GTO (manufactured by Heidel), using Aquares Five TPM ink manufactured by Toyo Ink Manufacturing ■, 10,
After printing 1,000 sheets, it was possible to obtain good printed matter without background smudges or scratches.

Example-3 Positive-type PS plate SMP manufactured by Konica ■ was added to the developer I of Example-1.
-N was immersed for 1 minute and rubbed lightly, and a good image without background stains could be obtained.

[Effects of the Invention] As described above in detail, the present invention provides a developer for photosensitive lithographic printing plates that does not require dampening water and has almost no odor, generates little sludge, and can suppress foaming. I can do it. Further, according to the present invention, it is possible to provide a developer for photosensitive lithographic printing plates that does not require dampening water and can provide excellent scratch resistance, image quality, and dyeing properties. Furthermore, the present invention can provide a developer for photosensitive lithographic printing plates that does not require dampening water and can also be used to develop positive-working photosensitive lithographic printing plates.

Patent applicant Mitsubishi Kasei Corporation (1 other person) Agent
Patent Attorney Miyao Ichinose

Claims (1)

[Claims] A dampening water-free photosensitive lithographic printing plate having on a substrate at least a photopolymerizable primer layer, a photosensitive layer and a silicone rubber layer in this order from the substrate side, and the photosensitive layer containing at least a hydroxyl group-containing polymer and a diazo resin. 1. A developer for a photosensitive lithographic printing plate that does not require a dampening solution and is characterized by containing at least water, an alkali, and an organic solvent having a solubility in water of 20% by weight or more.