JPH02229090A - Photosensitive lithographic printing plate - Google Patents

Abstract

PURPOSE:To improve an image reproducibility by a method wherein in a photosensitive lithographic printing plate formed by providing a photosensitive composition containing 1,2-naphtoquinone diazide-4-sulfonate or 1,2-naphtoquinone diazide-4-sulfonamide on a substrate, as the substrate, the surface of an iron plate is plated and treated with a metal or metallic oxide sol. CONSTITUTION:The material of an iron plate used for a substrate includes an alloy of iron and other elements in addition to a pure iron. In a plating treatment, Ni, Cr, Cu, Zn, or Sn having an anti-corrosive effect to the iron material are used as a plating metal. A sol is formed by using a metal or metallic oxide as a dispersion medium. As the metallic oxide, a hydrate may be used. As the metal or metallic oxide as a dispersoid, all materials being positively charged in the sol can be used. It is preferable that a cathode electrolytic process or a dipping treatment in a treating liquid consisting of a hydrosol containing the metal and/or metallic oxide as a dispersoid is employed as a surface sol treating method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photosensitive lithographic printing plate that can be used as a positive type or a negative type and uses a 2-quinonediazide compound as a photosensitive component.

[Background of the invention]

A positive-working photosensitive lithographic printing plate generally has an ink-receptive photosensitive layer formed on a hydrophilic support, which becomes solubilized by exposure to actinic rays such as ultraviolet rays.

When this photosensitive layer is subjected to imagewise exposure and development, the non-image area is removed leaving the image area, and an image is formed.

In planographic printing, the difference in properties is utilized in that the image area is lipophilic and the non-image area is hydrophilic.

Usually, the photosensitive layer of a positive photosensitive lithographic printing plate contains an 0-quinonediazide compound as a photosensitive component.
Among the above-mentioned 0-quinonediazide compounds, 1,2-naphthoquinone-2-diazide-5 is particularly preferred from the viewpoint of sensitivity and cost.
- Sulfonic acid ester compounds are generally used as useful compounds.

Conventionally, the development of such positive photosensitive lithographic printing plates is usually carried out using a developer consisting of an alkaline aqueous solution, but the developing ability of the developer is subject to fluctuations under various conditions, such as fatigue due to large-volume processing, Deterioration due to air oxidation reduces the developing ability, and even after processing, the photosensitive layer in the non-image area of the printing plate may not be completely dissolved. Therefore, it is desired that a photosensitive lithographic printing plate has a wide range of development tolerance, showing the same developability as when processed with a standard developer even with a developer having a reduced processing ability as described above.

(Hereinafter, the permissible range of reduction in developing ability that allows proper development results to be obtained is referred to as under-development.) In addition, such photosensitive planographic printing plates have insufficient reproducibility of small dots when reproducing halftone images. , improvement is desired.

On the other hand, when such a photosensitive lithographic printing plate is subjected to image exposure and then subjected to heat treatment to produce a negative plate, there is a problem that the support becomes wavy, resulting in poor image reproducibility.

[Purpose of the invention]

Therefore, an object of the present invention is to have a wide range of appropriate development conditions (development latitude), and to have good reproducibility of small halftone dots.
Another object of the present invention is to provide a photosensitive lithographic printing plate which exhibits good image reproducibility when negative plate making is performed by heat treatment after image exposure.

[Structure of the invention]

The object of the present invention is to provide a photosensitive lithographic plate comprising: (1) a photosensitive composition containing 2-naphthoquinonediazide-4-sulfonic acid ester or 1,2-naphthoquinonediazide-4-sulfonic acid amide provided on a support; This is achieved by a photosensitive lithographic printing plate characterized in that the support is a support that has been plated on the surface of an iron plate and then surface-treated with a metal or metal oxide sol.

The present invention will be explained in detail below.

Materials for the iron plate used as the support for the photosensitive planographic printing plate of the present invention include pure iron as well as alloys of iron and other elements. Other elements that form alloys with iron include carbon, manganese, and nickel. As an alloy, specifically carbon! (
alloys of carbon (0.04-1.7%) and iron), cast iron with a higher carbon content than carbon steel, and special m containing other elements (e.g. manganese, nickel, chromium, cobalt, tungsten, molybdenum). (For example, manganese steel, nickel steel, chromium steel, nickel-chromium steel), etc.

The carbon steel mentioned above includes extremely mild steel (carbon 0.25% or less),
Soft m (0.25-0.5%), hard steel (carbon mouth 5-1.
0%), extremely hard steel (carbon 1.0% or more).

A preferable iron plate is a cold rolled steel foil or a steel plate having a thickness of 30 to 250 μm. If the thickness of the steel plate exceeds 250 μm, it is difficult to process the plate material and is also uneconomical in terms of material costs. Furthermore, if the thickness of the steel foil is less than 40 .mu.m, the manufacturing cost is currently too high and it is uneconomical. Note that among cold-rolled steel sheets, those with a thickness of 100 μm or less seem to be generally referred to as steel foil, and there is no definite definition.

In the present invention, it is preferable that the surface of the iron plate on the side that will become the printing plate be roughened before being plated. The degree of roughening is
It is preferable that the average roughness Ra (JIS B 0601) of the surface after surface treatment with metal or metal oxide falls within the range described later.

Various conventionally known methods can be used to roughen the surface of the iron plate, including mechanical methods, chemical methods, and electrolytic methods.

Examples of the mechanical method include a pole polishing method, a brush polishing method, and a polishing method using liquid honing.

Chemical methods include etching with a solution containing sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, oxalic acid, pyrophosphoric acid, ferric chloride, etc. The electrolytic method includes an electrolytic etching method and an electrolytic plating method. A preferable electrolytic plating method includes iron plating.

In the plating process in the present invention, Ni, Cr, Cu, Zn, or Sn, which has a rust-preventing effect on iron materials, is used as the plating metal. Note that the plating metal is not limited to the above-described single metal, but also includes an alloy containing one or more of these metals, or a composite plating of two or more of these metals. The thickness of the plating is not particularly limited, as long as it achieves the purpose of imparting corrosion resistance or adjusting the surface roughness, and the rest may be determined in consideration of economic efficiency.

After plating, chemical conversion treatment can be performed if necessary.

Chemical conversion treatment includes immersion in a solution containing chromate, dichromate, phosphate, molybdate, borate, perborate, etc., or electrolysis in the solution. It will be done.

Next, surface treatment using a metal or metal oxide sol in the present invention will be explained.

The sol used in the present invention is a sol using a metal or metal oxide as a dispersion medium, and the metal oxide may be a hydrate, and the metal or metal oxide as a dispersoid is positively charged in the sol. That's fine.

The metal that forms the dispersoid and the metal of the metal oxide are A(2
, Ti, Zr, Cr, Ni, Zn, Sn, Mn, Cu,
Co, Fe, Pb and Cd are preferred, A(2, Cr, Zr, Ni and Zn are more preferred, and AQ, Zr and Ni are particularly preferred).

In the sol used in the present invention, the metal and metal oxide are 2
More than one species can be mixed (this mixing may be done within the dispersoid particles or between the dispersoid particles) and used.

The particle size of the dispersoid made of metal or metal oxide is 1 to 500.
A range of nm is preferable; if it exceeds 500 nm, the adhesion of the sol to the aluminum plate will become uneven, and therefore the wood affinity will also become uneven; if it is less than Inm, it will be difficult to produce the sol and it will be very expensive, making it uneconomical. Missing.

In the surface treatment method using a sol according to the present invention, it is preferable to carry out cathodic electrolysis or immersion treatment in a treatment solution consisting of hydrosil containing metal and/or metal oxide as a dispersoid. The concentration of metals and metal oxides in the hydrosil is from 1 to
A range of 100g/12 is preferred. The concentration is Ig/ff
If it is less than 100 g/Q, there is no effect on hydrophilicity, and if it exceeds 100 g/Q, it has no effect on hydrophilicity, but it is not preferable because it significantly impairs the appearance and at the same time unnecessarily consumes the sol due to drag-out.

The conditions for cathode electrolysis vary depending on the type of sol used, but suitably the current density is 0.5 to IOA/dm'', the treatment temperature is 5 to 50° C., and the treatment time is 1 to 60 seconds.

Dispersoids of metals or metal oxides have a positive charge in hydrosil and are easily adsorbed to aluminum plates, and the bond after adsorption is strong, so simply immersing them in the treatment solution is effective. . In addition, it shows good hydrophilicity even if it is dried as it is after soaking, or even if it is washed with water and then dried, and the woodphilicity lasts for a long time. Furthermore, since the dispersoids are positively charged in the sol, if electrolysis is carried out using an aluminum plate as a cathode, the metals and/or metal oxides that are the dispersoids will be electrophoretically adsorbed, and the dispersoids will be mixed with the metals and/or metal oxides. The bond with the aluminum plate becomes even stronger.

Further, in order to stabilize the sol, an inorganic acid such as chromic acid, phosphoric acid, sulfuric acid, or hydrochloric acid, an organic acid such as citric acid or acetic acid, or a surfactant may be added to the treatment liquid. Since these acids are easily removed by washing with water, they do not cause a decrease in corrosion resistance.

Since the hydrophilic film on the aluminum plate thus obtained is firmly bonded to the aluminum plate, it does not deteriorate over time. Further, it is preferable that the treatment liquid is neutral or weakly acidic and does not contain alkali ions.

Such surface treatment not only improves corrosion resistance but also effectively affects the adhesion of images formed on the printing plate. In particular, in the plating method, by appropriate growth of electrodeposited nuclei,
It is particularly effective because it also helps in secondary roughening of the surface. In that case, it is better to choose plating conditions that are uneven rather than smooth plating conditions, and it is economical to set the plating thickness so that the lower limit is the one that guarantees the corrosion resistance of the steel plate. It is not necessary to make the thickness of expensive metals such as Cr and Ni unnecessary, even if it is an inexpensive metal such as Zn.

In the support of the present invention, the surface-treated surface must have an average surface roughness Ra (JIS B
0601) is preferably in the range of 0.1-3 pm; if it is less than 0.1 µm, the surface will be nearly smooth and hydrophilicity will not be sufficient; if it exceeds 3 µm, it will be too rough and difficult to print. There will be a lot of blurring in the image and good printed matter will not be obtained. Methods to obtain a surface roughness favorable for hydrophilicity include mechanical methods such as using a grain chamber, chemical methods such as etching the metal surface with a chemical solution, thick plating on the metal plate surface using electrolysis, or There are electrochemical methods for etching the surface, but the easiest method is to make adjustments during electroplating. Such surface roughness may be evaluated after performing the above-mentioned surface treatment.

1,2-naphthoquinone-2-diazide 4 in the present invention
-sulfonic acid ester compound and 1,2-naphthoquinoso-2-diazide-4-sulfonic acid amide compound (hereinafter referred to as
Various known compounds can be used (these are referred to as "compounds of the present invention"), but in particular, a combination of 12-naphtho-2-diazide-4-sulfonic acid and a polycondensation resin of phenols and aldehydes or ketones. Ester compounds are preferably used.

Examples of the phenols include phenol, 0-
Cresol, m-cresol, p-cresol, 3.5
- Monohydric phenols such as xylenol, carvacrol, and thymol, dihydric phenols such as catechol, resorcinol, and hydroquinone, and trihydric phenols such as pyrogallol and phloroglucin. Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde, and furfural. Preferred among these are formaldehyde and benzaldehyde. Further, examples of the ketone include acetone and methyl ethyl ketone.

Specific examples of the polycondensation resin include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, and m-cresol formaldehyde resin.
Examples include 1p-mixed cresol/formaldehyde resin, resorcinol/benzaldehyde resin, and pyrogallol/acetone resin.

1 for the OH group of the phenol of the compound of the present invention
, 2-naphthoquinone-2-diazide-4-sulfonic acid has a condensation rate (reaction rate for one OH group) of 15 to 80%.
It is preferably 20% to 60%, more preferably 20% to 60%.

Furthermore, as the compound of the present invention, one of the polyhydroxy compounds is
, 2-naphthoquinone-2-diazide-4-sulfonic acid ester compounds, such compounds include:
For example, 1,2-7toquinonediazide-4-sulfonic acid cyclohexyl ester, 1-(1,2-naphthoquinonediazide-4-sulfonyl) =3,5-dimethylpyrazole, 1,2-naphthoquinonediazide-4-sulfone acid-4''-hydroxydiphenyl-4''-7so β
-naphthol ester, 2'-(1,2-naphthoquinonediazide 1-'-4-sulfonyloxy)-1-hydroxy-anthraquinone, 12-naphthoquinonediazide-
4-Sulfo7 acid-2,4-cyhydroxybenzophenone ester, l,2-naphthoquinonediazide-4-sulfonic acid 2,3,4-trihydroxybenzophenone ester, 1,2-naphthoquinonediazide-4-sulfonic acid- 2.3.4'.

4'-tetrahydroxybenzophenone ester, 12
-naphthoquinone diazide-4'-sulfonic acid chloride 2
condensate of 1 mole of 4,4'-dihydroxy-1,1'-diphenylsulfone, 1 mole of 4,2-naphthoquinone diazide 4-sulfonic acid chloride and 1 mole of purprocalin
Examples include molar condensates.

Furthermore, 1, 2- of polyurethane resins as shown below
A 71-quinone-2-diazide-4-sulfonic acid ester compound may also be used.

Further, as the compound of the present invention, an ester compound of a vinyl polymer having a phenolic hydroxyl group and 1,2-naphthoquinone-2-diazide-4-sulfonic acid can also be used. A vinyl polymer having a phenolic hydroxyl group that forms such an ester compound is a polymer having a unit having a phenolic hydroxyl group in its molecular structure,
Preferably, a vinyl polymer similar to the vinyl polymer having a structural unit having a phenolic hydroxyl group in its molecular structure used as the alkali-soluble resin described later is used.

1,2-naphthoquinone-2-diazide 4 in the present invention
As the -sulfonic acid amide compound, a condensate of 1,2-naphthoquinone-2-diazide-4-sulfonyl chloride and an amino compound is preferably used.

Examples of amino compounds include aniline, 0-aminophenol, m-aminophenol, p-aminophenol, chloroaniline, dichloroaniline, l-lichloroaniline, nitroaniline, aminenitroaniline, dinitroaniline, nitrochloroaniline, and cyanoaniline. , chloroanoaniline, phenoxyaniline, methoxyaniline, ethoxyaniline, carbamoylaniline, carboxyaniline and the like.

As the compound of the present invention, each of the above compounds may be used alone, or two or more thereof may be used in combination.

The proportion of the compound of the present invention in the photosensitive composition of the present invention is preferably 5 to 60% by weight, particularly preferably 10 to 50% by weight.

The photosensitive composition of the present invention can contain an acid anhydride and/or an organic acid. All known various organic acids can be used as the organic acid, but organic acids with a pKa value of 2 or more are preferred, and more preferably organic acids with a pKa value of 30 to 9.
．． 0, particularly preferably from 3.5 to 8.0. However, these pKa values are values at 25°C.

Such organic acids include, for example, the Basics of Chemistry Handbook ■ (
All organic acids described in Marukubi Co., Ltd. (1966, pp. 1054-1058) that can exhibit the above pKa value can be mentioned.

The proportion of the organic acid in the photosensitive layer is suitably 0.05 to 10% by weight, preferably 0.1 to 5% by weight.

As the acid anhydride, various known acid anhydrides are used, but cyclic acid anhydrides are preferred, such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc. , 3,6-ninodooxy-Δ4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, glutaric anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic acid, etc. . These acid anhydrides are contained in the photosensitive layer in an amount of 0.05 to 10% by weight, especially 0.1% by weight.
The content is preferably 5% by weight.

The photosensitive composition of the present invention includes, as an alkali-soluble resin,
Although various resins known in the art can be used, novolac resins and vinyl polymers having a structural unit having a phenolic hydroxyl group in the molecular structure are particularly preferred.

Novolac resins preferably used in the present invention include:
Examples include resins obtained by condensing phenols and formaldehyde in the presence of an acid catalyst; examples of the phenols include phenol, 0-cresol, m-cresol, p-cresol, 3.5-xylenol, 2,4 -xylenol, 2,5-xylenol, carvacrol,
Examples include thymol, catechol, resorcinol, hydroquinone, pyrogallol, and 70glucine.

The above phenolic compounds can be used alone or in combination with formaldehyde to obtain a resin. Among these, preferred novolak resins are phenol, m
A resin obtained by copolycondensing formaldehyde with at least one selected from -cresol (or -cresol) and p-cresol, such as phenol formaldehyde resin, m-cresol formaldehyde resin, 0-cresol・Formaldehyde resin,
Phenol/p-cresol/formaldehyde copolymer resin, m-cresol/p-cresol/formaldehyde copolycondensate resin, 0-cresol/p-cresol/formaldehyde copolycondensate resin, phenol/m
Examples include -cresol/p-cresol/formaldehyde copolycondensate resin and phenol/0-cresyl/p-cresol/formaldehyde copolycondensate resin. Furthermore, among the above-mentioned novolak resins, phenol/m-cresol/p-cresyl/formaldehyde resins are preferred.

In the present invention, the above novolac resins may be used alone or in combination of two or more.

The molecular weight (polystyrene standard) of the novolak resin is a weight average molecular weight Mw of 2. OX 103-2, O
X 10', number average molecular weight Mn is 7. OX 102-
The value is preferably within the range of 5.0x103, and more preferably Mw is 3.0x103. OX 103-6. OX1
03, Mn is a value within the range of 7.7×10 2 to 1.2×10 3 .

The measurement of the molecular weight of the novolak resin in the present invention is carried out using GP
C (gel permeation chromatography method).

In addition, vinyl polymers having a structural unit having a phenolic hydroxyl group in the molecular structure, which is preferably used in the present invention, are polymers formed by polymerization by cleavage of carbon-carbon double bonds, and the following general Polymers containing at least one structural unit of formulas [I] to (Vl) are preferably used.

General formula CI) -t7cR,R2-CR,÷0-CO-B-0)i General formula [■] -eCRIR2CR3+ C0NR,←A→--OH General formula [I[I) -←CRIR2CR3+ Coo-(' A-) BB-OH General formula [■] 1+CR, R2-CR3→- -0H General formula [■] OH In the formula, R1 and R2 are each a hydrogen atom, an alkyl group,
or represents a carboxyl group, preferably a hydrogen atom. R3 represents a hydrogen atom, a halogen atom, or an alkyl group, preferably a hydrogen atom or an alkyl group such as a methyl group or an ethyl group. R1 represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, preferably a hydrogen atom.

A represents an alkylene group which may have a substituent connecting a nitrogen atom or an oxygen atom and an aromatic carbon atom, and m is 0 to
represents an integer of 10, and B represents a phenylene group that may have a substituent or a naphthylene group that may have a substituent.

In the present invention, among these, a copolymer containing at least one structural unit represented by the general formula [■] is preferred.

The vinyl polymer preferably has a copolymer-type structure, and in this copolymer, a combination with at least one structural unit represented by each of the general formulas [■] to (Vl) Examples of monomer units that can be used include ethylenically unsaturated olefins such as ethylene, propylene, imbutylene, butadiene, and isoprene, such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, etc. Styrenes, such as acrylic acids such as acrylic acid and methacrylic acid, unsaturated aliphatic dicarboxylic acids such as itaconic acid, maleic acid, and maleic anhydride, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate,
Esters of α-methylene aliphatic monocarboxylic acids such as methyl methacrylate, ethyl methacrylate, and ethyl ethacrylate, nitriles such as acrylonitrile and methacrylonitrile, amides such as acrylamide, such as acrylanilide, p-chloroacrylic Anilides such as anilide, m-ditroacrylanilide, m-methoxyacrylanilide, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether , vinyl ethers such as β-chloroethyl vinyl ether, vinyl chloride, vinylidene chloride, vinylidencyanite, such as 1-methyl-1-methoxyethylene, 1.1-dimethoxyethylene, ■, 2-dimethoxyethylene, 1.1
- Ethylene derivatives such as dimethoxycarbonylethylene and 1-methyl-1-ditroethylene, such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, N-vinylpyrrolidone, etc. There are vinyl monomers such as compounds. These vinyl monomers exist in polymer compounds with a structure in which unsaturated double bonds are cleaved.

Among the above monomers, (meth)acrylic acids, esters of aliphatic monocarboxylic acids, and nitriles are used in combination with at least one of the structural units represented by general formulas [■] to [■]. shows excellent overall performance and is preferable. More preferred are methacrylic acid, methyl methacrylate, acrylonitrile, ethyl acrylate, and the like.

These monomers may be bonded to the vinyl polymer in either a block or random manner.

General formula CI) ~ [■] in the vinyl polymer
The content of the structural units represented by each of these is preferably 5 to 70 mol%, particularly preferably 10 to 40 mol%.

The above-mentioned polymers may be used alone or in combination of two or more thereof in the photosensitive composition.

The proportion of the alkali-soluble resin in the photosensitive composition of the present invention is preferably 50 to 95% by weight, more preferably 60 to 90% by weight.

The photosensitive composition of the present invention can contain a printout material consisting of a compound that generates an acid or free radical upon exposure to light, and a color change agent that changes its color tone by interacting therewith.

The photosensitive composition of the present invention may further contain a sensitizing agent such as a condensation resin of an alkyl-substituted phenol and formaldehyde.

The photosensitive composition of the present invention can achieve the object of the present invention by combining the above-mentioned materials, especially by containing the compound of the present invention, but in addition to each of these materials, necessary Depending on the situation, dyes such as dyes and pigments, sensitizers, plasticizers, surfactants, etc. can be added.

Furthermore, a photosensitive layer can be provided by dissolving each of these components in the following solvents and coating and drying the solution on the surface of a suitable support to form a photosensitive lithographic printing plate.

Solvents that can be used to dissolve each component of the photosensitive composition of the present invention include cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, and ethyl cellosolve acetate, dimethyl formamide, dimethyl sulfoxide, dioxane, acetone, Examples include cyclohexanone, trichloroethylene, and methyl ethyl ketone. These solvents can be used alone or in combination of two or more.

The coating method used for coating the surface of the support with the photosensitive composition of the present invention includes conventionally known methods, such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, and curtain coating. Coating etc. are possible. At this time, the coating amount varies depending on the application, but is preferably 0.5 to 5.0 g/m2 in terms of solid content.

The photosensitive lithographic printing plate to which the photosensitive composition of the present invention is applied is:
It can be developed using a conventional method.

For example, the film is exposed to light through a transparent positive film using a light source such as an ultra-high pressure mercury lamp, metal halide lamp, xenon lamp, or tungsten lamp, and then developed with various alkaline developers. As a result, only the unexposed portion remains on the surface of the support, forming a positive-positive relief image.

Examples of the alkaline developer include aqueous solutions of alkali metal salts such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, sodium diphosphate, and sodium triphosphate. . The concentration of alkali metal salt is 01~
10% by weight is preferred. Furthermore, an anionic surfactant, an amphoteric surfactant, and an organic solvent such as alcohol can be added to the developer as required.

In order to use the photosensitive lithographic printing plate of the present invention as a negative plate making method, a known method of heat treatment after image exposure may be applied.

〔Example〕

EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples unless the gist of the invention is exceeded.

Preparation of support Support-1 A flat surface of a steel plate with a thickness of 0.15 mm was roughened by etching with a Baume 40' ferric chloride solution, and then heated in a sulfate bath at a temperature of 50° C. and a current density of 5 A. /dm2, after plating Zn to 4 μm, the particle size was 1 as hydrophilic treatment.
100n Cr sol 20g/12. Phosphoric acid 10gIQ
Electrolysis was carried out with a solution containing the following for 30 seconds at a current density of 2 A/dm2 using a steel plate as a cathode, washed with water and dried to obtain Support-1.

Support-2 The surface of a rolled steel foil with a thickness of 0.09 mm was plated with 5 μM Fe to give a surface roughness (Ra) of 0.4 μm, and further heated at a temperature of 45° C. and a current density of 40 A using a Sargent bath.
Cr mesh with a thickness of 0.1 μm was performed under the conditions of /dm2, and immersed in an aqueous solution containing 30 g/(2, chromic acid 5 g/Q) of alumina sol (Alumina Sol-200, manufactured by Nissan Chemical) with a particle size of 50 nm as a hydrophilic treatment. and dried to obtain Support 2.

Support-3 A flat surface of a steel plate with a thickness of 0.15 mm was roughened by etching with a Baume 40' ferric chloride solution, and a sulfate bath was used for this, at a temperature of 50°C and a current density of 5 A/dm. in,
Zn was plated to a thickness of 4 μm.

Next, as a hydrophilic treatment, 30 g of zinc sol with a particle size of 40 nm was applied.
IQ, ') acid 10g10. The substrate was immersed in an aqueous solution containing the following and dried to obtain Support 3.

Comparative support-1 After degreasing an aluminum plate with a thickness of 0.24 mm, L7
g/Q in a hydrochloric acid bath at a bath temperature of 25°C with a current density of 50
Electrolytic polishing treatment was performed at A/dm2 for 25 seconds.

Next, desmatting treatment was performed at 50° C. for 113 seconds using a 10 g IQ NaOH aqueous solution.

Furthermore, 40% sulfuric acid aqueous solution, 30°C4 current density 1.5A
/dm2 for 2 minutes, then 90°C.
Hydrothermal treatment was performed for 25 seconds with an aqueous solution of. Subsequently, as a hydrophilic treatment, 20gIQ of Cr sol with a particle size of 1100n,
In a solution containing phosphoric acid Log/(2, using a steel plate as a cathode, 2
Electrolysis was carried out at a current density of A/dm2 for 30 seconds, washed with water and dried to obtain comparative support 1. Completed comparative support −
The surface roughness (Ra) of No. 1 was 0.5 μm.

Preparation of photosensitive liquid Photosensitive liquid-1 Condensate of pyrogallol acetone resin and 0-naphthoquinonediazide-4-sulfonyl chloride...2.2 parts by weight (
Weight average molecular weight (Mw) of the backbone polymer -2500.

Condensation rate of OH group: 33 mol%) Phenol 1m-cresol/p-cresol (weight ratio 3:4:3) Formalin novolac resin...8 parts by weight p-
Condensation product of octylphenol formalin novolac resin and 0-naphthoquinonediazide-5-sulfonylcresol (condensation rate of OH group 50 mol%) ...0.1 part by weight 2-trichloromethyl-β-(2'-benzofuryl) Hinil L3.
4-Oxacyasole...0.06 parts by weight Victoria Pure Blue BOH (manufactured by Hodokugaya Chemical Co., Ltd.)...008 parts by weight Methyl cellosolve...10 parts by weight Ethyl cellosolve...40 parts by weight Photosensitive liquid-2 Condensate of m-cresol formalin novolac resin and 0-naphthoquinone diazide-4 sulfonyl chloride...25 parts by weight (weight average molecular weight (M w) of backbone polymer -20000H
Condensation rate of groups: 25 mol%) p-hydroxyphenyl methacrylamide, acrylonitrile, ethyl acrylate, methacrylic acid (molar ratio: 2
0:20:58:2) copolymer (M w = 30,0
00) -=8 parts by weight p-octylphenol-formalin novolac resin...0.1 parts by weight 2-trichloromethyl-p-butoxystyryl-1,3,4 oxadiazole...0.08
Parts by weight Hyctoriapure Blue BOFI (manufactured by Odougaya Chemical Co., Ltd.) 0.08 parts by weight Methyl cellosolve 10 parts by weight Ethyl cellosolve 40 parts by weight The above-mentioned support and the above-mentioned photosensitive liquid are shown in the table below. Photosensitive lithographic printing plate samples No. 1-No. 4 were prepared using the combinations shown in 1.

Plate making conditions for these photosensitive lithographic printing plate samples are shown below-1.
(Positive plate making), plate making condition -2 (Negative plate making),
Lithographic printing plates No. 1 to No. 004 were prepared.

Next, the printing plate was printed under the following printing conditions, and the printed matter was evaluated. The results are shown in Table 2.

Plate making conditions-1 [Procedure] Exposure-1-Development-printing Exposure conditions-1 Exposure machine: Metal halide lamp "idle fin 2"
000°' 8.0mW/m2 (manufactured by Iwasaki Electric) Exposure time: 70 seconds Film original: Kodak Step Tablet No.
2. Conditions for developing halftone originals including Brunner dots Automatic development: Konica PS version automatic processor “PSQ-1315”
(manufactured by Konica Corporation) Developer solution: 6 times diluted solution of Conical S plate developer "5DR-1" (manufactured by Konica Corporation) Development temperature: 10 to 35°C Development time: 20 Second printing conditions Printing machine... Heidel GTO Ink... Shuso Best Cure "BFWRO"' (
Paper: Art paper Dampening water: 50 times diluted solution of 5EU-1 Printing speed: 4000 sheets/hour Plate-making conditions-2 [Procedure 1 Exposure-1-Heat treatment→ Exposure - 2 = Development - Printing heat treatment conditions =
180°C, 1 minute exposure conditions, near 0 second exposure -11 Development and printing were the same as plate making conditions -1.

Furthermore, as a comparative example, a printing plate (comparative printing plate-1) prepared using a conventionally known aluminum support (comparative support -1) was similarly evaluated, and the results are shown in Table 2.

Table 2 *1: The smoothness of the plate was impaired.

*2: ◎Good reproducibility of halftone dot shape.

○Dot shape reproducibility is between ◎ and ×.

x Poor reproducibility of halftone dot shape.

As is clear from the results in Table 2, the photosensitive lithographic printing plate of the present invention exhibits small changes in response to changes in developer temperature (wide latitude), good dot reproducibility, and good resolution.
And the print quality when negative plate making is good.

〔Effect of the invention〕

According to the present invention, the positive type and A photosensitive lithographic printing plate that can be used as a negative type can be obtained.

Claims (1)

[Claims] In a photosensitive lithographic printing plate comprising a support provided with a photosensitive composition containing 1,2-naphthoquinonediazide-4-sulfonic acid ester or 1,2-naphthoquinonediazide-4-sulfonic acid amide, the support A photosensitive lithographic printing plate characterized in that the support is plated on the surface of an iron plate and then treated with a sol of a metal or a metal oxide.