JP2894631B2 - No fountain solution photosensitive lithographic printing plate - Google Patents

Description

The present invention relates to a photosensitive lithographic printing plate requiring no fountain solution, and more particularly to a photosensitive lithographic printing plate requiring no fountain solution having a photopolymerizable primer layer.

[Prior art] Conventionally, in lithographic printing, it is necessary to perform printing with a delicate balance of water and ink by utilizing the lipophilicity of the image area and the hydrophilicity of the non-image area, and considerable skill is required. Needed.

That is, in a conventional printing method requiring a dampening solution, an image-like lipophilic portion is formed by exposing an image film to a plate material having a lipophilic photosensitive layer coated on a hydrophilic support, followed by development. A printing plate is formed by providing a hydrophilic portion which is a non-image portion. In printing, first, water is transferred to the non-image area, and then ink is transferred. The ink does not adhere to the non-image areas where water is present, but adheres only to the image areas. However, in this method, it is difficult to control the delicate balance between the dampening solution and the ink, causing emulsification of the ink, or causing the ink to mix in the dampening solution, causing poor ink density and background stains, which is a major cause of wasted paper. Had a big problem.

For this reason, development of a lithographic printing plate that does not require a dampening solution has been attempted. As such, a dampening solution-free photosensitive layer having a structure in which a primer layer, a photosensitive layer, and a silicone layer are provided in this order on a support is provided. Lithographic printing plates are known.

In a photosensitive lithographic printing plate that does not require dampening solution as described above,
As the primer layer, for example, a thermosetting type such as an epoxy resin described in JP-B-61-54219, JP-A-62-194255, or photocrosslinking described in JP-A-60-229031 was used. A photo-curing type is typically given.

[Problems to be Solved by the Invention] However, in the case of the thermosetting primer layer, since the primer layer is applied on a support and then cured by heating, the production efficiency is poor, and it is economically disadvantageous. Further, when the photosensitive layer is removed and the primer layer is exposed as an image area, there are disadvantages such as inferior stainability with a staining solution, and the photocrosslinkable primer layer has poor stainability, When the film is formed, problems such as extremely low sensitivity for curing the primer occur. Therefore, a sufficient primer layer in these respects has not been obtained yet, and a primer layer satisfying all of them has been desired.

Further, in the photosensitive lithographic printing plate not requiring a fountain solution having various primer layers as described above, a yellow pigment and a titanium oxide are used as a whitening agent for shielding the support in the primer layer, and for preventing halation. It is publicly known to add the like. However, since these titanium oxides and the like have poor dispersibility, there is a problem in the flatness of the primer layer after application, and particularly when the photosensitive layer is thin, it leads to a defect as a printing plate,
In addition, the developer has a very low permeability at the time of development, so that there is a disadvantage that image formation is not sufficiently performed.

Accordingly, an object of the present invention is to provide a novel photosensitive lithographic printing plate which does not require a fountain solution and eliminates the above-mentioned disadvantages. In particular, an object of the present invention is to provide a lithographic printing plate requiring no dampening solution, which is highly sensitive, has excellent scratch resistance, can minimize the influence of scratches on the support, and is more economical. It is in. Another object of the present invention is to provide a photosensitive lithographic printing plate which is excellent in flatness and excellent in developer permeability and, as a result, excellent in image forming properties, without using dampening solution.

[Means for Solving the Problems] The present inventors have conducted intensive studies in view of the above problems, and as a result, the above object of the present invention has at least a primer layer on a support,
In a fountain solution-free photosensitive lithographic printing plate having a photosensitive layer and a silicone rubber layer in this order from the support side, the primer layer comprises at least a hydroxyl group-containing polymer, an ethylenically unsaturated monomer or oligomer, a photopolymerization initiator, and zinc oxide. And a photolithographic printing plate requiring no fountain solution, characterized in that the lithographic printing plate requires no dampening solution.

 Hereinafter, the present invention will be described in more detail.

In the present invention, the primer layer contains a hydroxyl group-containing polymer, an ethylenically unsaturated monomer or oligomer, a photopolymerization initiator, and zinc oxide.

As the hydroxyl group-containing polymer, an ester or amide of an alcoholic hydroxyl group-containing poly (meth) acrylic acid is preferably used.

In the present invention, when the acrylic compound and the methacrylic compound are both referred to below, they are described as "(meth) acryl ...".

Examples of the polymer having an alcoholic hydroxyl group include 2-hydroxyethyl (meth) acrylate and N-
(4-hydroxyethylphenyl) methacrylamide,
Those having a constitutional unit derived from a monomer such as hydroxy-methyldiacetone (meth) acrylamide are exemplified. Particularly, a polymer having a structural unit derived from 2-hydroxyethyl (meth) acrylate is preferable.

The alcoholic hydroxyl group-containing polymer may be a copolymer, and the copolymerization component monomer includes (1) a monomer having an aromatic hydroxyl group, for example, N- (4
-Hydroxyphenyl) (meth) acrylamide, o
-, -M, p-hydroxystyrene, o-, -m, p-
(2) α, β such as (meth) acrylic acid and maleic anhydride
-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, N-dimethylaminoethyl (meth) Optionally substituted alkyl (meth) acrylates such as acrylate, (4) (meth) acrylamide, N-methylol (meth) acrylamide, N-ethylacrylamide, N-
Hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-
Optionally substituted (meth) acrylamides such as phenylacrylamide, N-nitrophenylacrylamide, N-ethyl-N-phenylacrylamide, (5) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, Vinyl ethers such as butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether; (6) vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate; (7) styrene, α-methylstyrene, chloromethylstyrene, and the like. (8) vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone; (9) ethylene, propylene, Olefins such as sobutylene, butadiene and isoprene; (10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, and the like. Particularly, (3) is preferable.

Although the hydroxyl group-containing monomer group in the above hydroxyl group-containing polymer is not particularly limited, it 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). Five,
When the value is lower than 000, the photosensitive layer may be exposed to a coating solvent or a developing solution even after photocuring. When the value is higher 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.

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 compounds are used. it 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 polycarboxylic acids, and the above-mentioned aliphatic polyhydroxy compounds. Hydroxy compounds,
Esters obtained by an esterification reaction with a polyhydroxy compound such as an aromatic polyhydroxy compound, and the like, and 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-diethoxyphenyl) ) Propane and the like. In addition, (meth) acrylamides such as ethylenebis (meth) acrylamide and hexamethylenebis (meth) acrylamide, or vinyl urethane compounds and epoxy (meth)
Acrylate and the like can be mentioned.

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

As the photopolymerization initiator, conventionally known photopolymerization initiators can be used, for example, benzoin, benzoin alkyl ether,
Benzophenone, anthraquinone, benzyl, Michler's ketone, a complex system of biimidazole and Michler's ketone, and the like can all be suitably used.

The amount of the photopolymerization initiator in the primer layer is 0.1 to 20% by weight, preferably 0.2 to 10% by weight.

In the present invention, as the zinc oxide contained in the primer layer, there are three methods of an indirect method, a wet method, and a direct method depending on the production method, but there is no particular limitation.

The average particle size of the zinc oxide is 0.2 μm or less, further 0.01 to 0.1
The particle size is preferably 5 μm, and particularly preferably particles containing particles exceeding 0.2 μm in an amount of 10% or less. Average particle size 0.2
If the value of μ is exceeded, the dispersibility becomes poor, and when the number of printed sheets is increased, it may cause background contamination or the like, which is not desirable. Such a particle size can be controlled by a manufacturing method or an operation such as filtration, but the method is not particularly limited. Here, the average particle size means a value observed and measured by an electron microscope.

Although untreated zinc oxide can be used as described above, dispersibility can be further improved by using it after treating with a silane coupling agent.

In the present invention, as the zinc oxide, preferably, FINEX (manufactured by Sakai Chemical Co., Ltd.), particularly FINEX with enhanced filtration, is preferably used.

In the present invention, the proportion of the zinc oxide in the primer layer is preferably 2 to 50% by weight, more preferably 5 to 30% by weight.

In the present invention, in addition to the above components, other fillers or antihalation agents as needed, a coloring agent such as a dye or a pigment, a coating improver, a plasticizer, a stabilizer, and a sensitizer are added to the primer layer. May be contained in a range not exceeding 10% by weight. It is also possible to use various conventionally known polymers, such as polyamide and polyurethane, which are usually used for the primer layer.

As the dye that can be contained in the primer layer,
For example, Victoria Pure Blue BOH, Oil Blue # 6
03, oil pink # 312, patent pure blue, crystal violet, leuco crystal violet,
Brilliant green, ethyl violet, methyl green, erythrosin B, basic fuchsin, malachite green, leucomalachite green, m-cresol purple, cresol red, xylenol blue, rhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, cyano-p Triphenylmethane-based, diphenylmethane-based, oxazine-based, xanthene-based, iminonaphthoquinone-based, azomethine-based or anthraquinone-based dyes represented by diethylaminophenylacetanilide and the like.

Examples of the coating improver include alkyl ethers (eg, ethyl cellulose and methyl cellulose), fluorine-based surfactants, and nonionic surfactants (eg, Pluronic L-64 (manufactured by Asahi Denka Co., Ltd.)) FC-430 (Sumitomo 3M) Manufactured).

As a plasticizer for imparting the flexibility and abrasion resistance of the coating film, for example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate,
Examples include tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrfurfuryl oleate, and oligomers of acrylic acid or methacrylic acid.

Further, various additives having a hydrophobic group, for example, p-octylphenol / formalin novolak resin, pt-butylphenol / formalin novolak resin, pt-butylphenol / benzaldehyde resin, in order to enhance the printing ink inking property of the image. And a modified novolak resin such as a rosin-modified novolak resin, or an o-naphthoquinonediazidosulfonic acid ester of these modified novolak resins (esterification ratio of OH groups: 20 to 70 mol%).

When the above-mentioned primer composition contains a pigment, if necessary, it is filtered with a suitable organic solvent by a known dispersion method (SGI, homogenizer, etc.) and then filtered. The primer layer of the present invention is formed by applying and drying the dispersion on a support, followed by photo-curing.

The photo-curing is performed by using a known light source such as a mercury lamp, a xenon lamp, or natural light, and exposing at a light exposure sufficient for curing the primer layer (usually, for example, in a range of 50 mJ / cm ^{2 to 5} J / cm ² ). Can be.

The curing is preferably performed at least before the application of the photosensitive layer is completed, and more preferably immediately after the application.

In the present invention, the thickness of the primer layer is 1 mg / dm ^{2 to} 500.
mg / dm ² , more preferably 3 mg / dm ²
300300 mg / dm ² .

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

Specifically, for example, an o-quinonediazide compound, o
A photo-solubilizing photosensitive layer containing a nitrobenzylcarbinol ester compound or the like; and a photo-insolubilizing photosensitive layer containing a diazo compound, a compound having an addition-polymerizable vinyl group, or the like.

The above-mentioned o-quinonediazide compound is a compound having at least one o-quinonediazide group, preferably an o-benzoquinonediazide group or an o-naphthoquinonediazide group, and is a known compound having various structures, for example, J. Coser. Light Sensitive Systems ”(John Willy and Sams, 1965) No. 33
Includes compounds described in detail on pages 9-353. Examples include esters of various hydroxyl compounds with benzoquinone-1,2-diazidosulfonic acid, naphthoquinone-1,2-diazidosulfonic acid, and the like. Examples of the hydroxyl compound used include a condensation resin of a phenol such as phenol, cresol and pyrogallol with a carbonyl group-containing compound such as formaldehyde, benzaldehyde and acetone, particularly a resin obtained by condensation in the presence of an acidic catalyst.

As the photosensitive layer containing a diazo compound, JP-A-1-1042
No. 86, a photosensitive layer comprising a diazo resin and a (meth) acrylate or amide-containing polymer having a hydroxyl group as essential components is preferred.

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

Examples of the compound having an addition polymerizable vinyl group include compounds having a terminal ethylene group having two or more polymerizable terminals having a boiling point of 100 ° C. or more under normal pressure, such as unsaturated carboxylic acid, unsaturated carboxylic acid and aliphatic polyether. Esters with hydroxy compounds, esters with unsaturated carboxylic acids and aromatic polyhydroxy compounds, unsaturated carboxylic acids and polyvalent carboxylic acids and the above-mentioned aliphatic polyhydroxy compounds, and polyvalent hydroxy compounds such as aromatic polyhydroxy compounds. Esters obtained by the esterification reaction of, for example, specifically,
It is described in JP-A-59-71048.

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.

In the present invention, the photosensitive layer may further contain a dye or pigment or a known exposure visible paint, a coatability improver, etc., as necessary, in addition to the above-described materials, and develop visible light, Visibility and applicability can be improved.

In the invention, it is preferable that the photosensitive layer contains a hydroxyl group-containing polymer. As such a hydroxyl group-containing polymer, those similar to those used for the primer layer as described above can be used.

The film thickness of the photosensitive layer is preferably from ^{0.1mg / dm 2 ~30mg / dm 2} , 0.5
mg / dm ² ~10mg / dm ² is more preferable.

In the present invention, a silicone rubber layer is further provided on the photosensitive layer. The silicone rubber used for the silicone rubber layer is preferably a linear or somewhat crosslinked organopolysiloxane. The organopolysiloxane generally has a molecular weight of one thousand to several hundred thousand, and is appropriately crosslinked in liquid or wax or rice cake form at normal temperature. The organopolysiloxane is classified into a condensation type and an addition type by a crosslinking method.

In the condensation type, crosslinking is performed by a condensation reaction, and water, alcohol, organic acid, and the like are released by the reaction.
Particularly useful condensation-type silicone rubbers include a mixture of a linear organopolysiloxane having a hydroxyl group at both terminals or a part of the main chain and a silicone crosslinking agent, or a product obtained by reacting a silicone crosslinking agent with a hydroxyl group. In any case, the addition of a condensation catalyst is advantageous in terms of the crosslinking rate.

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

In the formula, R ₁ and R ₂ each may have a substituent such as a cyano group, a halogen atom, a hydroxyl group, an alkyl, an aryl,
Alkenyl or a combination thereof, preferably a methyl group, a phenyl group, a vinyl group, and a trifluoropropyl group, particularly preferably a methyl group.

As the silicone crosslinking agent, Or a condensation type silicone cross-linking having a functional group represented by -OH (wherein R and R 'are alkyl groups), such as so-called acetic acid type, deoxime type, dealcohol type, deamino type, and dehydration type. Agents. Examples of such a crosslinking agent include tetraacetoxysilane, methyltriacetoxysilane, ethyltriacetoxysilane, phenyltriacetoxysilane, dimethyldiacetoxysilane, diethyldiacetoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, dimethyl Dimethoxysilane, vinyltrimethoxysilane, methyltris (acetone oxime) silane, methyltri (N-methyl, N-
Examples thereof include acetylamino) silane, vinyltri (methylethylketoxime) silane, methyltri (methylethylketoxime) silane or an oligomer thereof, and a reactive silane compound 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.

The addition type refers to an unsaturated group such as a vinyl group (-
CH = CH ₂ ) means that a hydrogen group in a crosslinking agent is added to crosslink.

Specific examples include those obtained by mixing a platinum-based catalyst (for example, chloroplatinic acid) with a vinyl group-containing organopolysiloxane, a hydrogenated organopolysiloxane, or the like.

The organopolysiloxane has the same repeating unit as the above-mentioned condensation type in the main chain.

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

It is also possible to use a condensation and addition type having a hydroxyl group, an unsaturated group and the like in one organopolysiloxane.

Among the commercially available products that can be obtained as the silicone rubber according to the present invention, preferred examples include KS-705F, KE manufactured by Shin-Etsu Co., Ltd.
Condensed silicone rubbers such as -41, 42, 44, Toshiba Silicone (YE5505, YF3057), Toray Silicone (SH-781, PRX-305, SH-237) and KS-837, KE-(Shin-Etsu) 103, KE
−106, KE-1300, Toshiba Silicone (TSE-3032, RTU)
-B, addition type silicone rubber such as Toray Silicone (product name) SH-9555.

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

In the present invention, the thickness of the silicone rubber layer is preferably as small as possible from the viewpoint of image quality and developability. dm ^{2 to} 50 mg / dm ² is preferable, and 5 mg / dm ^{2 to} 30 mg / dm ²
Is more preferred.

Further, the photosensitive lithographic printing plate requiring no fountain solution according to the present invention may be provided with a protective layer on the silicone rubber layer. As a method for providing the protective layer, a polypropylene film described in JP-B-61-614 is laminated. A method and a method of coating a high molecular polymer described in JP-A-61-27545 are known.

As the substrate used in the present invention, any substrate can be used as long as it has flexibility and can withstand the load applied during printing, and is not particularly limited, including a layer configuration. . For example, papers such as coated paper, a metal plate such as an aluminum plate, or a plastic film such as polyethylene terephthalate can be mentioned as an example, but an aluminum plate, or an aluminum foil and other composite materials are preferable,
From the viewpoint of printing durability, an aluminum plate is particularly preferred.

In the present invention, after 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, the primer layer as an image area An exposed, fountain-free 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.

Specific examples of preferred dyes include the following acidic dyes and basic dyes.

Examples of the acid dye include nitro dyes such as naphthol.
Yellow (CI Acid Yellow 1), monoazo dyes such as Fast Red A (CI Acid Red 88), disazo dyes such as naphthol blue black (CI Acid Black 1), nitroso dyes such as naphthol green B ( CI Acid Green 1), a triphenylmethane dye such as Patent Blue (CI Acid Blue 3), Brilliant Milling Green B (CI Acid Green 9), a xanthene dye such as Sulfo Rhodamina B (CI Acid Green) Red 52), anthraquinone dyes such as Alizarin Direct Blue A2G (CI Acid Blue 4)
0), azine dyes such as Woolfast Blue GL
(CI Acid Blue 102), quinoline dyes such as quinoline yellow (CI Acid Yellow 3), and the like. Preferred basic dyes include, specifically,
The following are mentioned.

Diphenylmethane dyes such as auramine O (CI Basic Yellow 2), triphenylmethane dyes such as magenta (CI Basic Violet 14), methyl violet (CI Basic Violet 1), malachite green (CI Basic Green 4) , Thiazole dyes such as Thioflavin T (CI
Basic yellow 1), xanthene dyes such as rhodamine B (CI basic violet 10), oxazine dyes such as Neil Blue BX (CI basic blue 12), thiazine dyes such as methylene blue B (CI basic blue 9) ), Azine dyes such as Safranin T (CI Basic Red 2), azo dyes such as Bismarck Brown G (CI Basic Red)
Brown 1), indocyanine dyes such as Astra Flaxin FF (CI Basic Red 12) and the like. In the present invention, a triphenylmethane dye is particularly preferably used. These dyes are used in an aqueous solution, and the concentration is preferably 0.1 g / to 10 g /.

In the present invention, when dyeing using these dye aqueous solutions, the temperature is 10 ° C to 50 ° C. The dyeing method is carried out by immersing the printing plate after development in a dyeing solution, or by applying an aqueous solution of a dye on the printing plate or spraying it on a shower. A dyeing aid can be added to the aqueous dye solution as needed.

As the dyeing aid, a water-soluble organic solvent, a surfactant, or the like is used to facilitate dyeing of the primer layer.

As the organic solvent, ethanol, solfit, benzyl alcohol and the like are preferably used, and as the surfactant, a nonionic surfactant is preferable in terms of foaming properties.

The light source used for the exposure may be any general-purpose light source including ultraviolet light having a wavelength of 180 nm or more and visible light, and particularly, a carbon arc lamp, a mercury lamp, a xenon lamp, a metal halide lamp, and a strobe are preferable.

As a developer used in the development processing, the following polar solvents, alkali compounds such as amines, surfactants, aliphatic hydrocarbons (hexane, heptane, "Isoper E.
HG "(trade name of aliphatic hydrocarbons manufactured by Esso Chemical) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.) or halogenated hydrocarbons (trichlene, etc.) were added as necessary. Things.

Polar solvents Alcohols (methanol, ethanol, water, 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 acetate, etc.) It can be carried out by various known methods, such as rubbing with a developing pad containing a suitable developing solution or rubbing with a developing brush after pouring the developing solution onto the plate surface.

EXAMPLES Hereinafter, the present invention will be described in more detail 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 added under ice cooling to 4 g
0.9 g of concentrated sulfuric acid was dissolved. To this reaction solution, 1.0 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 ice cooling.
The reaction mixture was added dropwise to 500 ml of ethanol under ice cooling, 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 in which 6.8 g of zinc chloride was dissolved was added to this solution. The resulting precipitate was filtered, washed with ethanol, and dissolved in 150 ml of pure water. To this solution, a cold concentrated aqueous solution in which 8 g of ammonium hexafluorophosphate was dissolved was added. The resulting precipitate was collected by filtration, washed with water, and dried at 30 ° C. for 24 hours to obtain diazo resin-1.
I got

The weight average molecular weight (Mw) in terms of styrene of the diazo resin obtained by measuring the coupling product with β-naphthol by the GPC method.
Was 1500 and the number average molecular weight was 500.

Example-1 The following primer layer composition was applied on a 0.24 mm-thick degreased aluminum substrate (manufactured by Mitsubishi Aluminum Co., Ltd.) at 60 ° C. using a wheeler and dried at 100 ° C. for 2 minutes to provide a primer layer. Was. The dry film thickness was 130 mg / dm ² .

The dispersion of the primer layer composition was performed using a high-pressure valve homogenizer.

After coating and drying, Unicure (Ushio Inc.)-16
Exposure was performed at 0 W, 4 m / min.

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

(Photosensitive composition) (1) diazo resin-1 100 parts (2) 2-hydroxyethyl methacrylate, N- (4-hydroxyphenyl) methacrylamide, methacrylic acid copolymer resin having a molar ratio of 40/55/5 ( Mw = 4.2 × 10 ⁴ ) 100 parts (3) Orange IV 8 parts (4) Methyl lactate 900 parts Next, the following silicone rubber composition was applied on the above-mentioned photosensitive layer so as to have a thickness of 2.0 g / m ² , and 100 Dry at 4 ° C. for 4 minutes.

Next, a 6 μm thick one-side matted polypropylene film was laminated on the silicone rubber layer to obtain a photosensitive lithographic printing plate sample 1 requiring no dampening water.

A lithographic printing plate sample requiring no dampening solution was prepared in the same manner except that the amount of zinc oxide in the primer layer of Sample 1 was changed to 40 parts.

After adhering a positive film to the upper surface of the above plate material under vacuum, 400 mJ / cm using a metal halide lamp as a light source
² was exposed. Next, after immersing in the following developer-1 for 1 minute to perform standard development, 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 the photosensitive layer. In each case, good images were obtained.

(Developer-1) Potassium silicate 9 parts Potassium hydroxide 4 parts Water 87 parts A continuous weighting type scratch strength tester Haydon manufactured by Shinto Kagaku Co., Ltd. After scratching with a sapphire needle with a diameter of 0.2 mm using -18 and a load of 50 g, the Aqualess Five TPM manufactured by Toyo Ink Mfg. Co., Ltd. Using the ink, 10,000 sheets were printed, and a good printed matter free of background stains and scratches was obtained.

For sample 1, sensitivity, glossiness and scratch resistance were evaluated by the following methods. Table 1 shows the results.

Sensitivity: After the step tablet is brought into vacuum contact with the top surface of the plate material, the metal tablet is used as a light source.
Exposure was performed at 0 mJ / cm ² . Developed and stained as described above, and the maximum number of steps stained was taken as the sensitivity.

Gloss: Measured by a gloss meter manufactured by Horiba, Ltd. The higher the value, the better the gloss and the better the smoothness.

Scratch resistance: Haydon 1 scratch strength tester manufactured by Shinto Kagaku Co., Ltd.
Evaluated using 8,0.2 mm sapphire needle.

Comparative Example 1 Sample 2 was obtained in the same manner as in the preparation of Sample 1, except that zinc oxide in the primer layer was removed in Example 1. When this was developed in the same manner as in Example 1, the developer penetration was extremely poor, and a good image could not be obtained.

Comparative Example 2 Sample 3 was prepared in the same manner as in Sample 1, except that the zinc oxide in the primer layer of Example 1 was changed to titanium oxide (0.03 μm, P-25 Nippon Aerosil Co., Ltd.). . When the developing treatment was carried out in the same manner as in Example 1, the developer permeability was extremely poor, and a good image could not be obtained.

Comparative Example-3 Sample 4 was prepared in the same manner as in Example 1, except that the primer layer composition was changed to the following composition, and the evaluation was performed in the same manner as in Example 1 except that the exposure amount was increased by 8 times. Table 1 shows the results.

(Primer layer composition) (1) 18 parts of diazo resin-1 (2) Copolymer resin (Mw = 4.0 × 1) having a molar ratio of 34/66 of 2-hydroxyethyl methacrylate and methyl methacrylate
0 ⁴⁾ 92 parts (3) .gamma.-methacryloxypropyltrimethoxysilane 2 parts (4) zinc oxide (Sakai Chemical Co., Ltd.: F-FINEX) 40 parts (5) KEY-YELLOW 402 (Dainippon Ink and Chemicals ( (Yellow pigment) 8 parts (6) Methyl lactate 600 parts It can be seen that Sample No. 1 of the present invention provides a good image by development and is superior to Comparative Sample 4 in all aspects of sensitivity, glossiness and scratch resistance.

Example 2 Copolymer resin (Mw = 4.0 × 1) having a molar ratio of 34/66 of a binder and 2-hydroxyethyl methacrylate / methyl methacrylate in the primer layer composition of Example 1
0 ^4), polyvinyl formal (Mw = 3.6 × 10 ⁴⁾ was prepared to dampening water required photosensitive lithographic printing plate sample in the same manner except for changing 100 parts. Further, when the image was developed in the same manner as in Example 1, a good image was obtained.

Example 3 (addition type silicone layer) A photosensitive lithographic printing plate sample requiring no dampening solution was prepared in the same manner as in Example 1 except that the silicone layer composition was changed as follows. Further, when development was performed in the same manner as in Example 1, a good image was obtained.

Silicone rubber layer composition α, ω-divinyl polydimethylsiloxane (number average molecular weight about 12000) 100 parts Methyl hydrogen polysiloxane (number average molecular weight about 3000) 3 parts Chloroplatinic acid 0.1 part Hexane 1400 parts Example-4 Example- A lithographic printing plate sample requiring no dampening solution was prepared in the same manner except that the composition of the photosensitive layer in Example 1 was changed as follows. Further, when development was performed in the same manner as in Example 1, a good image was obtained.

[Effects of the Invention] As described in detail above, according to the present invention, the primer is excellent in photocurability, excellent in scratch resistance, the influence of the support on the substrate can be suppressed as much as possible, and furthermore economical. A photosensitive lithographic printing plate requiring no dampening solution can be provided. Further, according to the present invention, it is possible to provide a photosensitive lithographic printing plate which is excellent in flatness and excellent in developer permeability, and as a result, is excellent in image forming properties and requires no dampening solution.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Akio Kasakura, 1000 Kamoshita-cho, Midori-ku, Yokohama-shi, Yokohama, Japan Inside Mitsubishi Chemical Research Laboratory (72) Inventor Seiji Goto 1 Sakura-cho, Hino-shi, Tokyo Konica Corporation (72) Norito Suzuki, Inventor No. 1, Sakura-cho, Hino-shi, Tokyo Konica Co., Ltd. (72) Inventor Nomasa left, No. 1, Sakura-cho, Hino-shi, Tokyo Konica Co., Ltd. (56) References JP Hei 2-7049 (JP, A) JP-A-63-280251 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/00, 7/11

Claims (1)

(57) [Claims] 1. A lithographic printing plate requiring no fountain solution comprising at least a primer layer, a photosensitive layer and a silicone rubber layer on a support in this order from the support side. A lithographic printing plate requiring no dampening solution, which contains a water-soluble unsaturated monomer or oligomer, a photopolymerization initiator, and zinc oxide, and is photocured before application of a photosensitive layer.