JPH0872431A - Photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE: To provide a photosensitive planographic printing plate excellent in printing durability, hard to generate the contamination of a non-image line part, good in small spot reproducibility and dot reproducibility, capable of obtaining printed matter sharp in dot shape, having wide water width and capable of being produced by adding slight alteration to existing equipment CONSTITUTION: A photosensitive planographic printing plate is obtained by using aluminum support having pits formed on the surface thereof by electrolytic surface roughening treatment so that 85% or more of pits has a pit diameter of 1-3μm or an aluminum plate subjected to electrolytic surface roughening treatment in a nitric acid electrolyte and subsequently uniformly pressed under pressure of 10-200g/cm<2> and further subjected to anodic oxidation treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive lithographic printing plate, and more specifically, it has excellent printing durability, is hard to stain non-image areas, has good dot reproducibility and tone reproducibility, and has a halftone dot pattern. A photosensitive lithographic printing plate that gives a printed matter with sharp dots.
Also, the present invention relates to a photosensitive lithographic printing plate having excellent printing durability, a wide water width, and a non-image area that is not easily soiled.

[0002]

BACKGROUND OF THE INVENTION A photosensitive lithographic printing plate is one in which a photosensitive layer is provided on a hydrophilic support, and a positive photosensitive lithographic printing plate comprising a support and a layer of a positive photosensitive composition is provided on the support. There is a negative-working photosensitive lithographic printing plate having a negative-working photosensitive composition layer provided on a support.

Conventionally, the support used for these photosensitive lithographic printing plates is required to have excellent hydrophilicity and water retention property and excellent adhesiveness to the photosensitive layer from the viewpoint of printability. Has been done.

In order to meet these requirements, a support for a photosensitive lithographic printing plate usually uses an aluminum plate whose surface has been subjected to a roughening treatment called graining. These surface roughening methods include mechanical surface roughening methods such as ball polishing, brush polishing, blast polishing, and buff polishing.
The electrolytic surface-roughening method of electrolytically treating the surface of a support with an alternating current or direct current in an acidic electrolyte such as hydrochloric acid or nitric acid, or the so-called chemical surface-roughening method of selectively dissolving and roughening the surface chemically is known. There is.

The aluminum plate which has been grained by these methods has a soft surface and is apt to be worn as it is, so an oxide film is formed by anodizing. The surface of the aluminum plate treated in this way is hard and has excellent wear resistance, and also has good hydrophilicity and water retention, and also has excellent adhesion to the photosensitive layer.

In recent years, printed matter has been required to have good finish and high quality, and so-called high-definition printing has become popular. In these high-definition printing, the minimum dot size, so-called dot size is several μm,
In the conventional photosensitive lithographic printing plate, the pit diameter formed on the support by the roughening is larger than the size of the dot,
The dot shape on the printing plate is not sharply reproduced, reproducibility is significantly impaired, and the finish of the printed matter is also impaired.

Among the conventional surface-roughening methods, the electrolytic surface-roughening method is relatively easy to control the shape of the rough surface, and a fine rough surface can be obtained. The shape of the dots on the plate cannot be reproduced sharply,
The finished product was not satisfactory. Further, it is known that the pit diameter is specified in order to improve printing durability and stain resistance. For example, US Pat. No. 4,301,229 discloses cumulative pit diameter. Defining the frequency distribution and centerline average roughness is described in U.S. Pat. No. 3,861,917, in which the depth of the rough surface is defined, and in Canadian patent 955,449. ,
The height and diameter of the peaks of the rough surface are defined in German Patent 1,813,443, and the height difference of the rough surface is defined in JP-A-55-132294. To define the average depth is disclosed in Japanese Patent Laid-Open No. 5-24376, which defines the pit diameter and the maximum depth in a direction perpendicular to the diameter. The shape of the dots could not be sharpened.

If anodization is performed immediately after graining, the resulting anodized film becomes black due to insoluble substances (abrasive residue, cutting debris, aluminum oxide, etc.) generated during graining. , At the same time that the appearance value is significantly impaired, the sensitivity of the photosensitive layer provided thereon is reduced or varies, and it becomes difficult to distinguish between the image area and the non-image area after development. The drawbacks are that it becomes difficult to adjust the water / ink balance and the non-image area becomes dirty.

In order to avoid these drawbacks, an intermediate treatment is usually performed before the anodizing treatment. Examples of these intermediate treatment methods include the chemical etching method described in JP-B-51-33444 and JP-A-51-26113.
The electrochemical etching method described in the publication is known. These processes are called desmut.

Japanese Patent Publication No. 48-28123 proposes to desmut the aluminum plate electrolytically roughened in hydrochloric acid by an alkali etching method. Although the stain resistance is improved, there is a drawback that the fine grain structure is destroyed by the alkaline etching with the alkaline aqueous solution and the printing durability is lowered. Further, Japanese Patent Publication No. 2-12752 proposes to perform desmut treatment by an alkali etching method on an aluminum plate electrolytically roughened in a nitric acid-based electrolytic solution. According to these methods, excellent printing durability can be obtained, but there is a problem in that the non-image area is stained.

Japanese Patent Publication No. 62-25117 proposes to subject a mechanically surface-roughened aluminum plate to an alkali etching treatment and then an electrolytic surface-roughening treatment in an acidic electrolytic solution. However, there is a problem in that a large amount of equipment is required to carry out these methods, and manufacturing equipment costs and operating costs are high.

In particular, when the roughening of the support for the photosensitive lithographic printing plate is carried out by electrolytic surface roughening in a nitric acid-based electrolytic solution, emulsification is carried out on the edges of the convex projections caused by the electrolytic roughening treatment. Ink is caught and stains occur on the non-image areas, and the unevenness of the grain projections causes uneven printing durability.The edges of the grain projections are resistant to the pressure applied during printing. There is a problem that the printing durability is poor because there is no sheet.

Therefore, it has been desired to eliminate these drawbacks that occur when the surface of a support for a photosensitive lithographic printing plate is roughened by electrolytic surface roughening in a nitric acid-based electrolytic solution.

[0014]

Therefore, the object of the invention described in claim 1 is as follows.
To provide a photosensitive lithographic printing plate which is excellent in printing durability, is hard to stain non-image areas, has good small dot reproducibility and halftone dot reproducibility, and can obtain a printed matter having a sharp halftone dot shape. It is in.

The objects of the inventions set forth in claims 2 to 3 are:
An object of the present invention is to provide a photosensitive lithographic printing plate which has excellent printing durability, is hard to stain the non-image area, has a wide water width, and can be produced by making a slight change to the existing equipment.

[0016]

The above objects of the present invention are as follows: (1) Electrolytic surface roughening, in a photosensitive lithographic printing plate having a layer of a photosensitive composition on an anodized aluminum support. A photosensitive lithographic printing plate, wherein 85% or more of the pits formed on the surface of the treated aluminum support have a pit diameter of 1 to 3 μm. (2) After electrolytically roughening an aluminum plate in a nitric acid-based electrolytic solution, a pressure of 10 to 200 g / cm ² is uniformly applied to the surface and further anodized, and then a layer of the photosensitive composition is formed. A photosensitive lithographic printing plate characterized by being provided. (3) The aluminum plate is electrolytically surface-roughened in a nitric acid-based electrolytic solution, then desmutted, and then uniformly surface-coated.
A photosensitive lithographic printing plate comprising a layer of a photosensitive composition after applying a pressure of about 200 g / cm ² and further anodizing. Can be achieved by

The present invention will be described in detail below.

First, the photosensitive composition of the present invention will be described.

The photosensitive composition of the present invention is not particularly limited, and in the present invention, the photosensitive composition generally used for a photosensitive lithographic printing plate can be used. Examples of the photosensitive composition that can be used in the present invention include the following. 1) Photocrosslinking type photosensitive resin composition The photosensitive component in the photocrosslinking type photosensitive resin composition is composed of a photosensitive resin having an unsaturated double bond in the molecule,
For example, US Pat. Nos. 3,030,208, 3,435,237 and 3,622,32.
As described in No. 0 specification, etc., as a photosensitive group in the polymer main chain.

[0020]

Embedded image And a polyvinyl cinnamate having a photosensitive group on the side chain of the polymer. 2) Photopolymerizable photosensitive resin composition A photopolymerizable composition containing an addition-polymerizable unsaturated compound, which is a monomer having a double bond or a monomer having a double bond and a polymer binder. A representative of such a composition is, for example, US Pat. No. 2,760,8.
No. 63 and No. 2,791,504.

Examples of the photopolymerizable composition include a composition containing methyl methacrylate, a composition containing methyl methacrylate and polymethyl methacrylate, a composition containing methyl methacrylate, polymethyl methacrylate and polyethylene glycol methacrylate monomers. , A photopolymerizable composition such as a composition containing methyl methacrylate, an alkyd resin and a polyethylene glycol dimethacrylate monomer.

These photopolymerizable photosensitive resin compositions include photopolymerization initiators (eg, those commonly known in the art).
Benzoin derivatives such as benzoin methyl ether, benzophenone derivatives such as benzophenone, thioxanthone derivatives, anthraquinone derivatives, acridone derivatives, etc.)
Is added. 3) Photosensitive Composition Containing Diazo Compound A preferable example of the diazo compound used in the photosensitive composition is a diazo resin represented by a condensate of an aromatic diazonium salt and formaldehyde or acetaldehyde. Particularly preferably, a reaction product of a condensate of a condensate of p-diazophenylamine with formaldehyde or acetaldehyde, for example, hexafluorophosphate, tetrafluoroborate, perchlorate or periodate is reacted with the condensate. Diazo resin inorganic salt which is a substance, and is described in US Pat. No. 3,300,309,
Examples thereof include a diazo resin organic salt which is a reaction product of the condensate and sulfonic acids.

The diazo resin is preferably used with a binder. As the binder, various polymer compounds can be used, preferably JP-A-54-9.
A monomer having an aromatic hydroxyl group described in Japanese Patent No. 8613, for example, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, o-, m- or p-hydroxy. Copolymers of styrene, o-, m- or p-hydroxyphenyl methacrylate with other monomers, U.S. Pat. No. 4,1.
23,276, polymers containing hydroxyethyl acrylate units or hydroxyethyl methacrylate units as main repeating units, natural resins such as shellac and rosin, polyvinyl alcohol,
Linear polyurethane resins described in U.S. Pat. No. 3,751,257, phthalated resins of polyvinyl alcohol, epoxy resins which are condensates of bisphenol A and epichlorohydrin, cellulose acetate, cellulose acetate phthalate, etc. Examples include derivatives. 4) Photosensitive composition containing o-quinonediazide compound The o-quinonediazide compound is a compound having an o-quinonediazide group in the molecule, and examples of the o-quinonediazide compound that can be used in the present invention include: Examples thereof include o-naphthoquinonediazide compounds, for example, ester compounds of o-naphthoquinonediazide sulfonic acid with a polycondensation resin of phenols and aldehydes or ketones.

Examples of the phenols in the polycondensation resin with the above-mentioned phenols and aldehydes or ketones include phenol, o-cresol, m-cresol,
Examples include monohydric phenols such as p-cresol, 3,5-xylenol, carvacrol, thymol, dihydric phenols such as catechol, resorcin, and hydroquinone, and trihydric phenols such as pyrogallol and phloroglucin. Examples of the aldehyde include formaldehyde,
Examples thereof include benzaldehyde, acetaldehyde, crotonaldehyde, furfural and the like. Of these, preferred are formaldehyde and benzaldehyde. Examples of ketones include acetone and methyl ethyl ketone.

Specific examples of polycondensation resins with phenols and aldehydes or ketones include phenol-formaldehyde resin, m-cresol-formaldehyde resin, m- and p-mixed cresol-formaldehyde resin, resorcin-benzaldehyde resin, Examples include pyrogallol / acetone resin.

In the o-naphthoquinonediazide compound, the condensation rate of o-naphthoquinonediazide sulfonic acid with respect to the OH groups of phenols (reaction rate with respect to one OH group) is preferably 15% to 80%, more preferably 2%.
It is 0% to 45%.

Further, as the o-quinonediazide compound used in the present invention, the following compounds described in JP-A-58-43451 can also be mentioned. That is, for example, 1,2-benzoquinone diazide sulfonic acid ester, 1,2-naphthoquinone diazide sulfonic acid ester, 1,2-benzoquinone diazide sulfonic acid amide,
Known 1,2-quinonediazide compounds such as 1,2-naphthoquinonediazide sulfonic acid amide, and more specifically, J. Kosar "Light-Sensitive Systems" No. 339. Pp. 352 (1965), John Willie
And Sons (John Willey & Sons) (New York) and W S De Forest (WSDe F)
1,2-benzoquinonediazide-4-sulfonic acid phenyl ester, 1, described in "Photoresist", Vol. 50 (1975), McGraw Hill, Inc. (New York).
2,1 ′, 2′-di- (benzoquinonediazide-4-sulfonyl) -dihydroxybiphenyl, 1,2-benzoquinonediazide-4- (N-ethyl-N-β-naphthyl) -sulfonamide, 1,2- Naphthoquinonediazide-5-sulfonic acid cyclohexyl ester, 1- (1,
2-naphthoquinonediazide-5-sulfonyl) -3,5
-Dimethylpyrazole, 1,2-naphthoquinonediazide-5-sulfonic acid-4'-hydroxydiphenyl-4 '
-Azo-β-naphthol ester, N, N-di- (1,
2-naphthoquinonediazide-5-sulfonyl) -aniline, 2 '-(1,2-naphthoquinonediazide-5-sulfonyloxy) -1-hydroxy-anthraquinone,
1,2-naphthoquinonediazide-5-sulfonic acid-2,
4-dihydroxybenzophenone ester, 1,2-naphthoquinonediazide-5-sulfonic acid-2,3,4-trihydroxybenzophenone ester, 1,2-naphthoquinonediazide-5-sulfonic acid chloride 2 mol and 4,
Condensate with 1 mol of 4'-diaminobenzophenone, 1,
2-naphthoquinonediazide-5-sulfonic acid chloride 2
, A condensate of 1,4'-dihydroxy-1,1'-diphenylsulfonic acid 1 mol, a condensate of 1,2-naphthoquinonediazide-5-sulfonic acid chloride 1 mol and purpurogallin 1 mol, 1,2 -Naphthoquinone diazide-
A 1,2-quinonediazide compound such as 5- (N-dihydroabietyl) -sulfonamide can be exemplified. In addition, Japanese Examined Patent Publications No. 37-1953 and 37-3627
Nos. 37-13109, 40-26126, 40-3801, 45-5604, 45-27.
No. 345, No. 51-13013, JP-A-48-965.
The 1,2-quinonediazide compounds described in JP-A No. 75, 48-63802 and 48-63803 can also be mentioned.

Of the above o-quinonediazide compounds,
An o-quinone diazide ester compound obtained by reacting 1,2-benzoquinone diazide sulfonyl chloride or 1,2-naphthoquinone diazide sulfonyl chloride with pyrogallol-acetone condensation resin or 2,3,4-trihydroxybenzophenone is particularly preferable.

In the present invention, as the o-quinonediazide compound, the above compounds may be used alone or in combination of two or more kinds.

The proportion of the o-quinonediazide compound in the photosensitive composition is preferably 5 to 60% by weight, and particularly preferably 10 to 50% by weight.

It is preferable to further add an alkali-soluble resin to the photosensitive composition containing the o-quinonediazide compound.

In the present invention, the alkali-soluble resin which is preferably used in combination with the o-quinonediazide compound is, for example, a novolac resin, a vinyl polymer having a phenolic hydroxyl group, or JP-A-55-57841. Examples thereof include condensation resins of polyphenols with aldehydes or ketones.

Examples of the novolac resin include phenol / formaldehyde resin, cresol / formaldehyde resin, phenol / cresol / formaldehyde copolymer resin as described in JP-A-55-57841, JP-A-55. Examples thereof include copolymer resins of p-substituted phenol and phenol or cresol and formaldehyde as described in JP-A-127553.

The molecular weight (polystyrene standard) of the novolac resin is preferably 3.00 × 10 in terms of number average molecular weight Mn.
^{2 to} 7.50 × 10 ³ , weight average molecular weight Mw of 1.00 ×
10 ^{3 to} 3.00 × 10 ⁴ , more preferably Mn of 5.0
0 × 10 ^{2 to} 4.00 × 10 ³ , Mw of 3.00 × 10 ^3.
˜2.00 × 10 ⁴ .

The above novolak resins may be used alone or in combination of two or more kinds.

When the novolac resin is used in combination, it is preferable that the novolac resin is contained in the photosensitive composition in an amount of 5 to 95% by weight.

The vinyl polymer having a phenolic hydroxyl group is a polymer having a unit having a phenolic hydroxyl group in its molecular structure, and is represented by the following general formula [I] to
A polymer containing at least one structural unit represented by [V] is preferable.

[0038]

Embedded image

In the general formulas [I] to [V], R
₁ and R ₂ each represent a hydrogen atom, an alkyl group or a carboxyl group, and preferably a hydrogen atom. R
₃ represents a hydrogen atom, a halogen atom or an alkyl group,
Preferred is a hydrogen atom or an alkyl group such as a methyl group and an ethyl group. R ₄ and R ₅ represent a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and preferably a hydrogen atom. A represents an optionally substituted alkylene group that connects a nitrogen atom or an oxygen atom and an aromatic carbon atom, m represents an integer of 0 to 10, and B represents a substituent. Represents a phenylene group which may be substituted or a naphthylene group which may have a substituent.

The above-mentioned vinyl polymer having a phenolic hydroxyl group used in the present invention preferably has a copolymer type structure having structural units represented by the above general formulas [I] to [V]. Examples of the monomer to be copolymerized include ethylenically unsaturated olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene, for example, styrene, α-methylstyrene, p
-Styrenes such as methylstyrene and p-chlorostyrene, for example, acrylic acids such as acrylic acid and methacrylic acid, for example, unsaturated aliphatic dicarboxylic acids such as itaconic acid, maleic acid and maleic anhydride, for example methyl acrylate , Ethyl acrylate, -n-butyl acrylate,
Esters of α-methylene aliphatic monocarboxylic acids such as isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate and ethyl ethacrylate. For example, nitriles such as acrylonitrile and methacrylonitrile, amides such as acrylamide, and anilides such as acrylanilide, p-chloroacrylanilide, m-nitroacrylanilide, and m-methoxyacrylanilide, such as acetic acid. Vinyl esters such as vinyl, vinyl propionate, vinyl benzoate and vinyl acetate, for example, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether and β-chloroethyl vinyl ether. , Vinyl chloride, vinylidene chloride, vinylidene cyanide, for example, 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxycarbonylethylene, 1-methyl-1- Ethylene derivatives such as nitroethylene, such as N-vinylpyrrole,
N-vinylcarbazole, N-vinylindole, N-
There are N-vinyl monomers such as vinylpyrrolidene and N-vinylpyrrolidone. These monomers are present in the polymer compound in a structure in which the unsaturated double bond is cleaved.

Of the above-mentioned monomers, aliphatic monocarboxylic acid esters and nitriles are preferable because they exhibit excellent performance for the purpose of the present invention.

These monomers may be bonded to the polymer used in the present invention in either a block or random state.

When a vinyl polymer having a phenolic hydroxyl group is used in combination, the vinyl polymer having a phenolic hydroxyl group is preferably contained in the photosensitive composition in an amount of 0.5 to 70% by weight.

As the vinyl polymer having a phenolic hydroxyl group, the above polymers may be used alone or in combination of two or more kinds. It can also be used in combination with other polymer compounds.

When an alkali-soluble resin is used in combination, o-
The proportion of the quinonediazide compound in the photosensitive composition is preferably 5 to 60% by weight, and particularly preferably 1
It is 0 to 50% by weight.

Further, a printout material capable of forming a visible image upon exposure can be added to the photosensitive composition of the present invention. The printout material is composed of a compound that generates an acid or a free radical upon exposure to light and an organic dye that changes its color tone by interacting with the generated acid or a free radical. Examples of the compound include, for example, JP-A-50-3.
O-naphthoquinonediazide-4 described in Japanese Patent No. 6209
-Sulfonic acid halogenide, trihalomethyl-2-pyrone and trihalomethyl-triazine described in JP-A-53-36223, and o-naphthoquinonediazide-4-sulfonic acid chloride described in JP-A-55-6244. Ester compound or amide compound with phenols or aniline having an electron-withdrawing substituent, JP-A-55-55
-77742, JP-A-57-148784 and the like may be mentioned halomethylvinyloxadiazole compounds and diazonium salts. Examples of organic dyes include Victoria Pure Blue BOH.
(Hodogaya Chemical Co., Ltd.), Patent Pure Blue (Sumitomo Mikuni Chemical Co., Ltd.), Oil Blue # 603 (Orient Chemical Co., Ltd.), Sudan Blue II (BA
SF), crystal violet, malachite green, fuchsin, methyl violet, ethyl violet, methyl orange, brilliant green, congo red, eosin, rhodamine 66 and the like.

In addition to the above-mentioned materials, the photosensitive composition of the present invention may optionally contain a plasticizer, a surfactant, an organic acid,
An acid anhydride or the like can be added.

Further, in order to improve the oil sensitivity of the photosensitive composition of the present invention, for example, p-
tert-butylphenol formaldehyde resin, pn
It is also possible to add an octylphenol formaldehyde resin or a resin in which these resins are partially esterified with an o-quinonediazide compound.

The layer of the photosensitive composition of the present invention can be formed by applying a coating solution prepared by dissolving or dispersing the photosensitive composition comprising each of these components in a solvent onto a support and drying it. it can.

Examples of the solvent that can be used when dissolving the photosensitive composition include, for example, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl. Ether, diethylene glycol diethyl ether, diethylene glycol monoisopropyl ether, propylene glycol, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl ethyl ether, ethyl formate, propylic acid formate , Butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate,
Examples thereof include ethyl butyrate, dimethylformamide, dimethylsulfoxide, dioxane, acetone, methylethylketone, cyclohexanone, methylcyclohexanone, diacetone alcohol, acetylacetone and γ-butyrolactone. These solvents may be used alone or in admixture of two or more.

The coating method used for coating the photosensitive composition on the surface of the support is a conventionally known method, for example, spin coating, wire bar coating, dip coating, air knife coating, spray coating, air spray coating, Methods such as electrostatic air spray coating, roll coating, blade coating and curtain coating are used. At this time, the coating amount varies depending on the use, but, for example, as solid content is 0.05 to 5.0 g.
A coating amount of / m ² is preferred.

Next, the support used for forming the photosensitive lithographic printing plate of the present invention will be described.

The aluminum support used in the present invention includes a support made of pure aluminum and an aluminum alloy. Various aluminum alloys can be used, for example, an alloy of aluminum with a metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, or nickel.

The aluminum support is preferably subjected to a degreasing treatment in order to remove rolling oil on the aluminum surface prior to roughening. As degreasing treatment, trichlene,
A degreasing treatment using a solvent such as thinner, an emulsion degreasing treatment using an emulsion such as kesilon and triethanol, and the like are used. In addition, an alkaline aqueous solution such as caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, it is possible to remove stains and oxide films which cannot be removed only by the above degreasing treatment.

For the electrolytic surface-roughening method of the support, any electrolytic solution generally used for electrolytic surface-roughening treatment can be used. A particularly preferable electrolytic surface-roughening method is a method of performing electrolytic surface-roughening in a nitric acid-based electrolytic solution.

The electrolytic surface-roughening treatment is described in, for example, Japanese Patent Publication No. 48-28123, British Patent No. 896,563 and Japanese Patent Laid-Open No. 53-67507, and these methods are used in the present invention. Can be used.

The voltage applied in electrolytic graining is 1
It is preferably -50 V, more preferably 2-30 V. The current density is preferably 10 to 150 A / dm ² and 2
0 to 100 A / dm ² is more preferable. The amount of electricity is 100
˜20,000 c / dm ² , preferably 100 to 10,000
c / dm ^2, more preferably 200~5000c / dm ^2. The temperature is preferably 10 to 50 ° C, more preferably 15 to 45 ° C. The nitric acid concentration is preferably 0.1 to 5% by weight.

If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid and the like can be added to the electrolytic solution.

Since smut is generated on the surface of the support obtained by the roughening treatment as described above, appropriate treatment such as washing with water or alkali etching is performed to remove the smut. It is generally preferred to do so. As such a processing, for example, Japanese Patent Publication No. 48-2812.
Treatment methods such as the alkali etching method described in JP-A No. 3 and the sulfuric acid desmutting method described in JP-A No. 53-12739 are mentioned.

In the present invention, 85 of pits formed on the surface of the aluminum support subjected to electrolytic surface roughening treatment.
% Or more has a pit diameter of 1 to 3 μm.
The pits having a pit diameter of 1 to 3 μm formed on the surface of the support are preferably 95% or more. There are 7 pits with a pit diameter of 1-2 μm formed on the surface of the support.
It is more preferably 5% or more.

In the present invention, 1 to 3 μm is formed on the surface of the support.
The conditions of the electrolytic surface roughening method and the anodic oxidation treatment method may be selected so that 85% or more of m pit diameter exists.

The pit diameter is a photographing magnification of 1500 to 5000.
It can be measured by using an electron micrograph taken at about double. The pit diameter as referred to in the present invention is represented by the linear distance from the edge of the pit indentation to the other edge.

In order for 85% or more of the pits formed on the surface of the aluminum support to have a pit diameter of 1 to 3 μm, the voltage applied in electrolytic graining is 1
It is preferably -50 V, more preferably 2-30 V. The current density is preferably 10 to 80 A / dm ² , and 20
-60 A / dm ² is more preferable. Electricity is 100-5
000 c / dm ² , preferably 100 to 4000 c / dm ² ,
More preferably, it is 200 to 1000 c / dm ² . The temperature is preferably 10 to 50 ° C, more preferably 15 to 45 ° C. The nitric acid concentration is preferably 0.1 to 5% by weight.

In the present invention, the aluminum plate is electrolytically surface-roughened in a nitric acid-based electrolytic solution, desmutted, and then uniformly spread on the surface of the aluminum plate at 10 to 200 g /
A pressure of cm ² is applied. If the pressure applied to the surface of the aluminum plate is 10 g / cm ² or less, the uniformity of printing durability cannot be obtained, and if it is 200 g / cm ² or more, the convex portions of the grain are excessively crushed and the printing durability is remarkably increased. Will fall. The pressure applied to the surface of the roughened support is 50 to 150 g / cm
More preferably, it is ² .

The method of applying pressure is not particularly limited,
It is preferable to use a carrying roller for pressurization, because no additional equipment is required.

The anodizing method used in the present invention is not particularly limited, and a known method can be used.
An oxide film is formed on the support by the anodizing treatment. In the present invention, the anodizing treatment includes sulfuric acid and / or
Alternatively, a method in which an aqueous solution containing phosphoric acid or the like at a concentration of 10 to 50% is used as an electrolytic solution and electrolysis is performed at a current density of 1 to 10 A / dm ² is preferably used.
A method of electrolyzing in sulfuric acid at a high current density described in US Pat. No. 68, a method of electrolyzing using phosphoric acid described in US Pat. No. 3,511,661, and the like can be used. .

The anodized support may be subjected to a sealing treatment if necessary. These sealing treatments can be performed by using known methods such as hot water treatment, boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment, and nitrite treatment.

It is preferable that the support is further provided with a hydrophilic layer. For the formation of the hydrophilic layer, US Pat.
Alkali metal silicates described in US Pat. No. 1,461, hydrophilic celluloses described in US Pat. No. 1,860,426, JP-A-60-149491 and JP-A-63.
-165183 gazette amino acid and its salt,
Hydroxyl group-containing amines and salts thereof described in JP-A-60-232998, phosphates described in JP-A-62-19494, and monomers having a sulfo group described in JP-A-59-101651. A polymer compound containing a unit can be used.

The photosensitive lithographic printing plate of the present invention can be made into a plate by exposing and developing it in a usual manner. For example, a relief image can be obtained by exposing a transparent original image having a line image, a halftone image and the like to a photosensitive surface in close contact with the light and then removing the photosensitive layer with an appropriate developing solution.

Light sources suitable for exposure include mercury lamps, metal halide lamps, xenon lamps, chemical lamps,
Examples include carbon arc lamps. The developer used for development includes, for example, sodium silicate, alkali metal silicates such as potassium silicate, sodium hydroxide,
An alkaline aqueous solution such as an aqueous solution of potassium hydroxide, sodium triphosphate, dibasic sodium phosphate, sodium carbonate, potassium carbonate or the like can be used. The concentration of the aqueous alkali solution at this time varies depending on the photosensitive composition and the type of alkali, but is generally in the range of 0.1 to 10% by weight. If necessary, an organic solvent such as a surfactant or alcohol can be added to the alkaline aqueous solution.

[0071]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 An aluminum plate having a thickness of 0.3 mm (material 1050, temper H
16) was immersed in a 10% sodium hydroxide aqueous solution kept at 85 ° C., degreased for 1 minute, and then washed with water.
The degreased aluminum plate was kept at 25 ° C.
% Aqueous sulfuric acid solution for 1 minute to neutralize and then wash with water.
Next, this aluminum plate was subjected to electrolytic surface roughening with an alternating current for 30 seconds in a 0.8% by weight nitric acid aqueous solution under the conditions of a temperature of 30 ° C. and a current density of 30 A / dm ² .
10% in 1% aqueous sodium hydroxide solution kept at 70 ° C
A desmut treatment for 2 seconds was performed. Then, in a 20% sulfuric acid aqueous solution, the temperature was 35 ° C. and the current density was 3 A / dm ²
Anodic oxidation treatment for 20 minutes, then hot water at 30 ℃ for 20 minutes
A hot water sealing treatment was performed for 2 seconds, and the aluminum support was obtained by drying at 80 ° C. for 5 minutes.

When the surface of the obtained aluminum support was photographed and observed by an electron microscope at a magnification of 3500 by a conventional method, 92% had a pit diameter of 1 to 3 μm and 79% had a pit diameter of 1 to 2 μm. .

A photosensitive composition coating solution having the following composition was applied to the obtained support using a wire bar and dried at 80 ° C. for 2 minutes to obtain a photosensitive lithographic printing plate. At this time, the coating amount of the photosensitive composition coating liquid was set to be 2.0 g / m ² as a dry weight.

<Photosensitive Composition Coating Liquid> Novolak resin (phenol / m-cresol / p-cresol molar ratio 10/54/36 and Mw 4000) 6.70 g of pyrogallol acetone resin (Mw: 3000) and o -Condensation product with naphthoquinonediazide-5-sulfonyl chloride (esterification rate 30%) 1.50 g Polyethylene glycol # 2000 0.20 g Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.08 g 2,4-bis ( Trichloromethyl) -6- (p-methoxystyryl) -s-triazine 0.15 g FC-430 (Sumitomo 3M Ltd.) 0.03 g cis-1,2 cyclohexanedicarboxylic acid 0.02 g Methyl cellosolve 100 ml

A positive original film having halftone dots and fine lines was brought into close contact with the obtained photosensitive lithographic printing plate, and 2 kW was used as a light source.
Exposure was carried out by irradiating at 8 mW / cm ² for 60 seconds using a metal halide lamp. The exposed photosensitive lithographic printing plate was developed with a commercially available developing solution (SD-32, manufactured by Konica Corporation, diluted 5 times, developing time 30 seconds, developing temperature 25 ° C.).

Printing is carried out using the obtained lithographic printing plate,
Water width, printing durability, and halftone dot shape were evaluated by the following evaluation methods. The obtained results are shown in Table 1. <Evaluation method><Evaluation of printing durability> The obtained lithographic printing plate was put on a printing machine (DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd.), and coated paper, dampening water (etching liquid SG manufactured by Tokyo Ink Co., Ltd.) -51,
Printing with ink (density 1.5%), ink (Toyo Ink Mfg. Co., Ltd., High Plus M. Red) until ink inking defects appear in the image area of the printed matter or ink adheres to the non-image area. Printing was performed, the number of printed sheets printed by that time was obtained, and printing durability was evaluated.

<Evaluation of water width> Printing was performed under the same conditions as in the evaluation of printing durability, the ink amount dial was kept constant, the water amount dial was changed, and the non-image area began to become dirty or the flat mesh portion was used. The dial value of the amount of water at which the ink starts to be entangled with the dial value of the amount of water at which the ink density in the image area is reduced was determined, and the difference was defined as the water width.

<Evaluation of halftone dot shape> 50 on a printed matter obtained by printing under the same conditions as in the evaluation of printing durability.
The shape of 2% halftone dot of 0 line / inch (dot size of film original: 7.18 μm) was observed with an optical microscope at a magnification of 500 times. ◯ ... Good points are obtained without shakiness. ×: There is a feeling of roughness, and good points cannot be obtained.

Example 2 In Example 1, the hot water sealing treatment was omitted, and instead, an anodic oxidation treatment was carried out, followed by immersion in a 1 g / liter aqueous solution of polyvinylphosphonic acid at 60 ° C. for 30 seconds. A lithographic printing plate was obtained in the same manner as in Example 1 except that.

With respect to the lithographic printing plate thus obtained, the water width, printing durability and halftone dot shape were evaluated in the same manner as in Example 1.
The obtained results are shown in Table 1.

Comparative Example 1 In Example 1, the conditions for electrolytic surface roughening treatment of an aluminum plate were set to a temperature of 30% in a 1.8% aqueous nitric acid solution.
4 by AC current under conditions of ℃ and current density of 150A / dm ^2.
An aluminum support and a lithographic printing plate were obtained in the same manner as in Example 1 except that the operation was performed for 0 seconds.

The surface of the obtained aluminum support was photographed and observed by an electron microscope at a magnification of 3500 by a conventional method. As a result, 73% had a pit diameter of 1 to 3 μm and 35% had a pit diameter of 1 to 2 μm. .

The water width, printing durability and halftone dot shape of the obtained lithographic printing plate were evaluated in the same manner as in Example 1.
The obtained results are shown in Table 1.

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[Table 1]

Example 3 An aluminum plate having a thickness of 0.3 mm (material 1050, temper H
16) was immersed in a 10% sodium hydroxide aqueous solution kept at 85 ° C., degreased for 1 minute, and then washed with water.
The degreased aluminum plate was kept at 25 ° C.
% Aqueous sulfuric acid solution for 1 minute to neutralize and then wash with water.
Then, this aluminum plate was electrolytically surface-roughened for 60 seconds with an alternating current in a 1.8% by weight aqueous nitric acid solution under the conditions of a temperature of 30 ° C. and a current density of 50 A / dm ² .
10% in 1% aqueous sodium hydroxide solution kept at 70 ° C
A desmut treatment for 2 seconds was performed. Then, using a roller made of copper, a pressure of 100 g / cm ² was uniformly applied to the surface of the support. Then, in a 20% aqueous solution of sulfuric acid, a temperature of 35
Anodic oxidation treatment for 1 minute at a temperature of 3 ° C. and a current density of 3 A / dm ² , followed by hot water sealing treatment with hot water at 30 ° C. for 20 seconds and drying at 80 ° C. for 5 minutes to form an aluminum support. Obtained.

A photosensitive composition coating solution having the following composition was applied to the obtained support using a wire bar and dried at 80 ° C. for 2 minutes to obtain a photosensitive lithographic printing plate. At this time, the coating amount of the photosensitive composition coating liquid was set to be 2.0 g / m ² as a dry weight.

<Photosensitive Composition Coating Liquid> Novolak resin (phenol / m-cresol / p-cresol molar ratio 10/54/36 and Mw 4000) 6.70 g of pyrogallol acetone resin (Mw: 3000) and o -Condensation product with naphthoquinonediazide-5-sulfonyl chloride (esterification rate 30%) 1.50 g Polyethylene glycol # 2000 0.20 g Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.08 g 2,4-bis ( Trichloromethyl) -6- (p-methoxystyryl) -s-triazine 0.15 g FC-430 (Sumitomo 3M Ltd.) 0.03 g cis-1,2 cyclohexanedicarboxylic acid 0.02 g Methyl cellosolve 100 ml

A positive original film having halftone dots and fine lines was brought into close contact with the obtained photosensitive lithographic printing plate, and 2 kW was used as a light source.
Exposure was carried out by irradiating at 8 mW / cm ² for 60 seconds using a metal halide lamp. The exposed photosensitive lithographic printing plate was developed with a commercially available developing solution (SD-32, manufactured by Konica Corporation, diluted 5 times, developing time 30 seconds, developing temperature 25 ° C.).

With respect to the lithographic printing plate thus obtained, water width and printing durability were evaluated in the same manner as in Example 1. The obtained results are shown in Table 2.

Example 4 In Example 3, the hot water sealing treatment was omitted, and instead, an anodic oxidation treatment was carried out, followed by immersion in a 1 g / liter polyvinylphosphonic acid aqueous solution at 60 ° C. for 30 seconds. A lithographic printing plate was obtained in the same manner as in Example 3 except that.

With respect to the lithographic printing plate thus obtained, water width and printing durability were evaluated in the same manner as in Example 1. The obtained results are shown in Table 2.

Comparative Example 2 A lithographic printing plate was obtained in the same manner as in Example 3 except that pressure was not applied to the aluminum plate.

The obtained lithographic printing plate was evaluated for water width and printing durability in the same manner as in Example 1. The obtained results are shown in Table 2.

Comparative Example 3 A lithographic printing plate was obtained in the same manner as in Example 3, except that a pressure of 300 g / cm ² was applied to the aluminum plate.

With respect to the lithographic printing plate thus obtained, water width and printing durability were evaluated in the same manner as in Example 3. The obtained results are shown in Table 1.

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[Table 2]

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EFFECT OF THE INVENTION 85% or more of the pits of the present invention have a size of 1 to 3 μm.
A photosensitive lithographic printing plate that uses an aluminum support that has been subjected to electrolytic surface roughening with a pit diameter of m has excellent printing durability, does not easily stain non-image areas, and has small dot reproducibility and tone reproducibility. It is possible to obtain a printed matter that is good and has a sharp halftone dot shape.

The aluminum plate of the present invention is electrolytically surface-roughened in a nitric acid-based electrolytic solution and then uniformly coated on the surface by 10 to 200.
A photosensitive lithographic printing plate using a support subjected to a pressure of g / cm ² and further anodized is excellent in printing durability, has a wide water width, and is hard to stain non-image areas. It can be easily manufactured by slightly changing the existing equipment.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Matsubara 1 Sakura-cho, Hino City, Tokyo Konica Co., Ltd. (72) Inventor Fumiyuki Matsuo 1000, Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Co., Ltd.

Claims (3)

[Claims] 1. A photosensitive lithographic printing plate having a layer of a photosensitive composition on an aluminum support which has been electrolytically surface-roughened and anodized, and the surface of the aluminum support which has been electrolytically surface-roughened. 85% or more of the pits formed are 1 to
A photosensitive lithographic printing plate having a pit diameter of 3 μm. 2. An aluminum plate is electrolytically surface-roughened in a nitric acid-based electrolytic solution, a pressure of 10 to 200 g / cm ² is uniformly applied to the surface of the aluminum plate, and further anodizing treatment is performed. A photosensitive lithographic printing plate comprising a layer. 3. An aluminum plate is electrolytically surface-roughened in a nitric acid-based electrolytic solution, then desmutted, then uniformly pressured on the surface of 10 to 200 g / cm ² , and further anodized. A photosensitive lithographic printing plate comprising a layer of a photosensitive composition.