JPH0627646A - Photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To prevent the components of a photosensitive layer from remaining in non-image parts after exposing and developing by specifying the pH of an aq. nitrite soln. for processing the surface of a base. CONSTITUTION:The base subjected to at least a surface roughening treatment and anodic oxidation treatment in this order is used for the base. The surface roughening treatment is executed by executing a mechanical surface roughening method or electrochemical surface roughening method, then subjecting a sand dressing treatment. Since smut is formed on the surface of the resulted base, the base is subjected to a proper treatment, such as washing with water or alkali etching in order to remove the smut. The processing by the aq. nitrite soln. is executed after the pretreatments. The nitrite of an alkaline metal is particularly preferably used in such a case. The nitrite is incorporated at 0.001 to 10wt.% into the aq. sol. The pH of the aq. nitrite soln. is adjusted to 8.0 to 11.0.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive lithographic printing plate, and more particularly to a photosensitive lithographic printing plate having improved developability and corrosion resistance.

[0002]

2. Description of the Related Art Conventionally, a photosensitive lithographic printing plate, for example, a positive type photosensitive lithographic printing plate, has an ink-receptive photosensitive layer provided on a hydrophilic support. When the photosensitive layer of the printing plate is subjected to image exposure and then the exposed photosensitive layer is developed with a developer, the photosensitive layer in the exposed area is removed and the surface of the hydrophilic support is exposed, while non-exposed. Part of the photosensitive layer remains on the surface of the support to form an ink-receptive image part, whereby a lithographic printing plate is obtained.

Such a lithographic printing plate is used for printing by utilizing the property that water and oil repel each other. Specifically, when the non-image area of the plate surface is moistened with water and then ink is applied to the plate surface, the ink repels in the non-image area due to the dampening water, so that the ink selectively adheres only to the image area. Then, when the ink in the image area is transferred to the transferred material, a printed material having an image corresponding to the image area is obtained.

Therefore, as a support for obtaining such a lithographic printing plate, when it is wet with water, it is excellent in hydrophilicity and water retention and also has an adhesiveness with a photosensitive layer which becomes an image portion which receives a printing pressure. Must be good. The photosensitive layer must have ink receptivity and high sensitivity to exposure, and must have high printing durability as the most important condition.

As a support satisfying these conditions,
The aluminum plate is the most excellent, and in order to obtain sufficient adhesion between the aluminum plate and the photosensitive layer, a surface treatment for mechanically roughening the surface of the support is performed. As the surface treatment method, for example, ball graining, wire graining, brush graining and the like are described in Japanese Patent Publication No. 50-40047 and Japanese Patent Publication No. 51-46003. In addition, Japanese Patent Publication No. 48-28123
No. 4,087,341, JP-A-53-67507, etc., a hydrochloric acid bath, a nitric acid bath or the like is used to apply a direct current or an alternating current to the surface of an aluminum plate to make it uniform and dense. An electrolytic graining method for forming a rough grain shape is described. Further, JP-A-56-150595 describes a method of controlling the adhesiveness between the support and the photosensitive layer by subjecting the surface of the support to sealing treatment with hot water, sealing treatment with silicate or the like. ing.

As described above, the support and the photosensitive layer are provided with sufficient adhesiveness, and the support such as an aluminum plate is further surface-treated to improve hydrophilicity and water retention, For example, Japanese Examined Patent Publication No. 36-22063, US Pat. No. 2,246,683, and No. 3,
160,506 describes that the hydrophilicity and water retention of the metal surface can be improved by chemically treating the metal surface with potassium fluorozirconate to form a film. Further, JP-A-53-131102 describes a support which is treated with an aqueous solution of potassium fluorozirconate and then with an aqueous solution of sodium silicate to improve hydrophilicity and water retention.

[0007]

However, in these methods, even if the effect of preventing the non-image area of the lithographic printing plate obtained by the development processing from being contaminated is recognized,
The planographic printing plate may not have sufficient corrosion resistance and the support may be corroded by the developing agent. When these photosensitive lithographic printing plates are imagewise exposed and then developed, the substances contained in the photosensitive liquid are strongly adsorbed to the plate surface in the non-image areas of the resulting lithographic printing plate, and During processing, it is not easily removed by the developing solution and remains, so that correction marks remain clearly, resulting in a non-uniform plate surface. Therefore,
Such a phenomenon becomes more prominent when a burning treatment, which is generally performed as a means for improving printing durability, is performed, and the lithographic printing plate obtained from the support treated by the above method is actually used. The use of printing is no longer tolerable.

In order to overcome the drawbacks of these conventional methods, some of the present inventors proposed to treat with nitrous acid or an aqueous solution containing nitrite, and to easily remove the resin component by this method. It was found that the water retention in the non-image area was excellent (Japanese Patent Laid-Open No. 2-289388). The present inventors have made extensive studies to further advance this method, and surprisingly, by selecting specific conditions which are not usually adopted in the treatment with nitrite or nitrite, the developer The inventors have found that the corrosion resistance to water and the water retention in the non-image area are dramatically improved, and have reached the present invention.

[0009]

SUMMARY OF THE INVENTION It is, therefore, a first object of the present invention to provide a photosensitive lithographic printing plate excellent in so-called developability in which components of the photosensitive layer do not remain in the non-image area after exposure and development. A second object of the present invention is to provide a photosensitive lithographic printing plate having high corrosion resistance to a developing solution.

Therefore, the object of the present invention is to provide a photosensitive lithographic printing plate having a photosensitive layer after treating the surface of a support which has been subjected to at least roughening and anodization in this order with an aqueous nitrite solution. And the pH of the nitrite aqueous solution is 8.0
Easily achieved by a photosensitive lithographic printing plate characterized by a 11.0. Hereinafter, the present invention will be described in more detail.

The support used in the present invention is preferably a support which can be set in an ordinary lithographic printing machine and can withstand a load applied during printing. For example, a metal such as aluminum, magnesium, zinc, chromium iron, copper or nickel. Examples thereof include a plate and an alloy plate of these metals. Further, a metal plate coated with chromium, zinc, copper, nickel, aluminum, iron or the like by plating or vapor deposition may be used. Of these, the preferred support is aluminum or its alloy.

The support used in the present invention is subjected to degreasing treatment, surface roughening treatment, anodizing treatment and the like which are commonly used in this technical field before the treatment with the aqueous nitrite solution. It is preferable to use a support which has been subjected to roughening treatment and anodizing treatment in this order. As degreasing treatment to remove rolling oil on the aluminum surface, solvent degreasing with trichlene, thinner, etc.,
Examples include emulsion degreasing with kerosene and triethanol. Further, in order to remove stains and natural oxide film which cannot be removed only by degreasing, the sample is immersed in an alkaline solution such as caustic soda having a concentration of 1 to 10% at 20 to 70 ° C. for 5 seconds to 10 minutes, and then a concentration of 10 to 20%. The method of immersing in an acidic solution such as nitric acid or sulfuric acid at 10 to 50 ° C. for 5 seconds to 5 minutes to perform neutralization after alkali etching and removal of smut can be mentioned.

As a roughening treatment method carried out for improving the adhesion to the photosensitive layer and improving the water retention property, a so-called mechanical surface roughening method of mechanically roughening the surface,
There is a so-called electrochemical surface-roughening method for electrochemically roughening the surface. Mechanical graining methods include ball polishing,
There are methods such as brush polishing, blast polishing, and buff polishing.
The electrochemical surface-roughening method includes, for example, a method of electrolytically treating the support with an alternating current or a direct current in an electrolytic solution containing hydrochloric acid, nitric acid, or the like. The support can be roughened by using any one of these methods or a combination of two or more methods.

Since smut is formed on the surface of the support obtained by the graining treatment as described above, appropriate treatment such as washing with water or alkali etching may be carried out to remove the smut. Generally preferred. Examples of such a treatment include the alkaline etching method described in Japanese Patent Publication No. 48-28123 and Japanese Patent Laid-Open No. 53-53.
Examples thereof include a treatment method such as a sulfuric acid desmutting method described in 12739.

The support used in the present invention usually has an oxide film formed on the support by anodic oxidation in order to improve abrasion resistance, chemical resistance and water retention. In this anodic oxidation, sulfuric acid and / or phosphoric acid or the like is generally used in an amount of 10-5.
A current density of 1 to 1 with an aqueous solution containing 0% as an electrolyte
A method of electrolyzing at 0 A / dm ² is preferably used,
Besides, a method of electrolyzing in sulfuric acid at a high current density described in U.S. Pat. No. 1,412,768 and electrolysis using phosphoric acid described in U.S. Pat. No. 3,511,661. There are ways to do it.

After the above-mentioned pretreatment, a treatment with an aqueous nitrite solution is performed. Examples of the nitrite used in the present invention include Ia, IIa, IIb, IIIb,
Examples thereof include nitrites or ammonium salts of metals of groups IVa, IVb, VIa, VIIa, and VIII, that is, ammonium nitrite. Examples of the metal salt include LiNO ₂ , N
_{aNO 2, KNO 2, Mg (} NO 2) 2, Ca (N
O ₂ ) ₂ , Zn (NO ₂ ) ₂ , Al (NO ₂ ) ₃ , Zr
(NO ₂ ) ₄ , Sn (NO ₂ ) ₄ , Cr (NO ₂ ) ₃ ,
Co (NO ₂ ) ₂ , Mn (NO ₂ ) ₂ , Ni (NO ₂ )
_{2 and the} like are preferable, and alkali metal nitrite is particularly preferable. Of course, two or more kinds of such nitrites can be used in combination, and further, they can be used in combination with nitrous acid.

The nitrite is preferably contained in the aqueous solution in an amount of 0.001 to 10% by weight. The pH of the aqueous nitrite solution is preferably adjusted to 8.0 to 11.0, more preferably 8.5 to 9.5. In order to adjust the pH of the nitrite aqueous solution to the above range, for example, various alkaline buffers and the like can be preferably used. The alkaline buffer is not limited, but examples thereof include a mixed aqueous solution of sodium hydrogen carbonate and sodium hydroxide, a mixed aqueous solution of sodium carbonate and sodium hydroxide, a mixed aqueous solution of sodium carbonate and sodium hydrogen carbonate, and sodium chloride and sodium hydroxide. A mixed aqueous solution of, a mixed aqueous solution of hydrochloric acid and sodium carbonate, a mixed aqueous solution of sodium tetraborate and sodium hydroxide, and the like can be preferably used. In addition, an alkali metal salt other than sodium salt, such as potassium salt, can be used as the above-mentioned alkaline buffer solution.

The treatment conditions for treating the surface of the support with the above-mentioned treatment solution include immersing in an aqueous nitrite solution kept at room temperature to 100 ° C. for 3 seconds to 300 seconds, or by using the aqueous nitrite solution on the support. It is preferable to apply it to. Furthermore, in a 0.1 wt% to 2 wt% aqueous solution of nitrite, 70 ° C to 95 ° C.
The treatment of immersing the support for 5 to 60 seconds is preferable.
In order to enhance the effect of the sodium nitrite treatment, ultrasonic waves may be applied during the treatment, and before the treatment, the support is immersed in hot water or alkaline aqueous solution at about 80 ° C to 95 ° C. May be. The support treated with the aqueous nitrite solution is then preferably dried or at 80 ° C to 95 ° C.
It is immersed in hot water and dried. After drying, the photosensitive layer may be provided immediately on the support, or the photosensitive layer may be provided after standing for a while. Additives can be added to the above-mentioned nitrite aqueous solution, if necessary. For example, water-soluble polymer,
A surfactant or the like can be added.

Next, the lithographic printing plate of the present invention is obtained by applying a photosensitive layer made of a photosensitive composition. The photosensitive substance used in this photosensitive layer is not particularly limited, and various kinds of substances usually used in photosensitive lithographic printing plates, for example, the following various substances are used.

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. No. 030,208, No. 3,4
35,237 and 3,622,320, etc., as a photosensitive group in the polymer main chain.

[0021]

[Chemical 1]

Examples thereof include a photosensitive resin containing, and polyvinyl cinnamate having a photosensitive group in the side chain of the polymer.

2) Photopolymerizable Photosensitive Resin Composition A photopolymerizable composition containing an addition polymerizable unsaturated compound, which comprises a monomer having a double bond or a monomer having a double bond and a high content. A typical example of such a composition comprising a molecular binder is disclosed in, for example, US Pat. No. 2,760,8.
No. 63 and No. 2,791,504.

As an example, a composition containing methylmethacrylate, a composition containing methylmethacrylate, polymethylmethacrylate, a composition containing methylmethacrylate, polymethylmethacrylate and polyethyleneglycoldimethacrylate monomers, methylmethacrylate, alkyd A photopolymerizable composition such as a composition containing a resin and a polyethylene glycol dimethacrylate monomer is used. This photopolymerization type photosensitive resin composition includes a photopolymerization initiator usually known in this technical field (for example, benzoin derivative such as benzoin methyl ether, benzophenone derivative such as benzophenone, thioxanthone derivative, anthraquinone derivative, acridone derivative, etc. ) Is added.

3) Photosensitive Composition Containing Diazo Compound The diazo compound in the photosensitive composition is, for example, preferably a diazo resin represented by a condensate of an aromatic diazonium salt and formaldehyde or acetaldehyde. Particularly preferably, a salt of a condensate of p-diazodiphenylamine and formaldehyde or acetaldehyde, for example, a reaction product of a condensate of hexafluoroborophosphate, tetrafluoroborate, perchlorate or periodate with the condensate. And a diazo resin organic salt which is a reaction product of the condensate and a sulfonic acid as described in US Pat. No. 3,300,309. Furthermore, the diazo resin is
It is preferably used with a binder. As the binder, various polymer compounds can be used, but a monomer having an aromatic hydroxyl group as described in JP-A-54-98613, such as N-, is preferable.
(4-hydroxyphenyl) acrylamide, N- (4
-Hydroxyphenyl) methacrylamide, o-, m
-, Or p-hydroxystyrene, o-, m-, or p-hydroxyphenylmethacrylate copolymers with other monomers, described in U.S. Pat. No. 4,123,276. Polymers containing such hydroxyethyl acrylate units or hydroxyethyl methacrylate units as the main repeating unit, natural resins such as shellac and rosin, polyvinyl alcohol, as described in US Pat. No. 3,751,257. Polyamide resin, linear polyurethane resin as described in U.S. Pat. No. 3,660,097, polyvinyl alcohol phthalated resin, epoxy resin condensed from bisphenol A and epichlorohydrin, cellulose acetate, cellulose acetate Cellulose induction such as phthalate There are included.

4) Photosensitive Composition Containing o-quinonediazide Compound In the photosensitive composition containing an o-quinonediazide compound used in the present invention, it is preferable to use an o-quinonediazide compound and an alkali-soluble resin in combination. o
Examples of the quinonediazide compound include ester compounds of o-naphthoquinonediazidesulfonic acid and a polycondensation resin of phenols and aldehydes or ketones.

Examples of the phenols include monohydric phenols such as phenol, o-cresol, m-cresol, p-cresol, 3,5-xylenol, carvacrol and thymol, and divalent catechol, resorcin, hydroquinone and the like. Examples include trihydric phenols such as phenol, pyrogallol, and phloroglucin. Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde, furfural and the like. Preferred of these are formaldehyde and benzaldehyde. Examples of the ketone include acetone and methyl ethyl ketone.

Specific examples of the polycondensation resin include phenol / formaldehyde resin, m-cresol / formaldehyde resin, m- and p-mixed cresol / formaldehyde resin, resorcin / benzaldehyde resin, pyrogallol / acetone resin. To be OH of phenols of the o-naphthoquinonediazide compound
The condensation rate of o-naphthoquinonediazide sulfonic acid with respect to the group (reaction rate with respect to one OH group) is preferably 15% to 80%, more preferably 20 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 used. That is, 1, 2
-Benzoquinone diazide sulfonate, 1,2-
Known 1,2-naphthoquinone diazide sulfonic acid ester, 1,2-benzoquinone diazide sulfonic acid amide, 1,2-naphthoquinone diazide sulfonic acid amide, etc.
Quinone diazide compounds, more specifically J. Kosar "Light-Sensitive Systems" (Light-Sensitive System)
ems) pp. 339-352 (1965), John.
Willie & Sons (John Willey &
Sons, Inc. (New York) and W.S. De Forest's "Photoresist", Volume 50,
(1975), McGraw H
ill) (New York) 1,2-
Benzoquinonediazide-4-sulfonic acid phenyl ester, 1,2,1 ', 2'-di- (benzoquinonediazide-4-sulfonyl) -dihydroxybiphenyl, 1,2
-Benzoquinonediazide-4- (N-ethyl-M-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-sulfone-
2,4-dihydroxybenzophenone ester, 1,2
-Naphthoquinonediazide-5-sulfonic acid-2,3,4
-Trihydroxybenzophenone ester, a condensate of 1,2-naphthoquinonediazide-5-sulfonic acid chloride 2 mol and 4,4'-diaminobenzophenone 1 mol,
Condensate of 2 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mol of 4,4'-dihydroxy-1,1'-diphenylsulfone, 1 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride Examples thereof include a 1,2-quinonediazide compound such as a condensate of 1 mol of purpurogallin and 1,2-naphthoquinonediazide-5- (N-dihydroabietyl) -sulfonamide. In addition, Japanese Examined Patent Publication Nos. 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. As the o-quinonediazide compound used in the present invention, the above compounds may be used alone or in combination of two or more kinds.

The proportion of the o-quinonediazide compound used in the present invention in the photosensitive composition is 5 to 60% by weight.
Is preferable, and particularly preferably 10 to 50% by weight. Examples of the alkali-soluble resin used in the photosensitive composition of the present invention include novolac resins, vinyl polymers having phenolic hydroxyl groups, polyhydric phenols and aldehydes or ketones described in JP-A-55-57841. And a condensation resin thereof.

Examples of the novolac resin used in the present invention include phenol / formaldehyde resin, cresol / formaldehyde resin, JP-A-55-57841.
Phenol-cresol-formaldehyde copolymer resin as described in JP-A-55-127
Examples thereof include copolymer resins of p-substituted phenol and phenol or cresol and formaldehyde as described in Japanese Patent No. 553.

The novolak resin preferably has a number average molecular weight Mn of 3.00 × (polystyrene standard).
10 ^{2 to} 7.50 × 10 ³ , and the weight average molecular weight Mw is 1.
00 × 10 ^{3 to} 3.00 × 10 ⁴ , more preferably Mn
Is 5.00 × 10 ^{2 to} 4.00 × 10 ³ , and Mw is 3.0.
It is 0 × 10 ^{3 to} 2.00 × 10 ⁴ . The above novolak resins may be used alone or in combination of two or more.

The proportion of the above novolak resin in the photosensitive composition of the present invention is 5 to 95% by weight. Further, the vinyl polymer having a phenolic hydroxyl group used in the present invention is a polymer having a unit having the phenolic hydroxyl group in the molecular structure, and has the following general formula [I] to
Polymers containing at least one structural unit of [V] are preferred.

[0035]

[Chemical 2]

[Wherein R₁And R₂Is hydrogen source
Child, alkyl group or carboxyl group, preferably hydrogen atom
Represents a child. R₃Is a hydrogen atom, a halogen atom or an alkyl
Group, preferably a hydrogen atom, a methyl group or an ethyl group.
Represents an alkyl group such as a vinyl group. R _FourIs a hydrogen atom, Archi
Represents an alkyl group, an aryl group or an aralkyl group, preferably
Represents a hydrogen atom. A is nitrogen atom or oxygen atom and fragrance
An optionally substituted substituent that connects to a group carbon atom
Represents a alkylene group, m represents an integer of 0 to 10, and B represents
Is a phenylene group which may have a substituent or a substituent
Represents a naphthylene group which may have. ]

The polymer used in the photosensitive composition of the present invention preferably has a copolymer type structure, and is used in combination with the structural units represented by the above general formulas [I] to [V]. Examples of the monomer unit that can be used include ethylenically unsaturated olefins such as ethylene, propylene, isobutylene, butadiene, and isobrene, and styrenes such as styrene, α-methylstyrene, p-methylstyrene, and p-chlorostyrene. For example, acrylic acid, acrylic acid such as methacrylic acid, for example, itacone, maleic acid, unsaturated aliphatic dicarboxylic acids such as maleic anhydride, such as methyl acrylate, ethyl acrylate, -n-butyl acrylate, isobutyl acrylate, Dodecyl acrylate, 2-chloroethyl acrylate, phenyl acrylate , Α-methylene aliphatic monocarboxylic acid esters such as α-methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, and ethyl methacrylate, for example, acrylonitrile, nitriles such as methacrylonitrile, and amides such as acrylamide, For example, anilides such as acrylanilide, p-chloroacrylanilide, m-nitroacrylanilide, and 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, vinylidene cyanide, for example, 1-methyl-1-methoxyethylene, 1,1
-Dimethoxyethylene, 1,2-dimethoxyethylene,
1,1-dimethoxycarbonylethylene, 1-methyl-
Ethylene derivatives such as 1-nitroethylene, for example N-
There are N-vinyl monomers such as vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidene, and N-vinylpyrrolidone. These vinyl-based monomers are present in the polymer compound with a structure in which the unsaturated double bond is cleaved.

Of the above 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 bound to the polymer used in the present invention in either a block or random state. The proportion of the vinyl polymer used in the present invention in the photosensitive composition is 0.5 to 7.
It is 0% by weight.

As the vinyl polymer used in the present invention, 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. A printout material capable of forming a visible image upon exposure can be added to the photosensitive composition. The printout material is composed of an organic dye which changes its color tone by interacting with a compound which forms an acid or a free radical upon exposure to light, and examples of the compound which forms an acid or a free radical upon exposure include, for example, JP-A-50.
O-naphthoquinonediazide-4-sulfonic acid halogenide described in JP-A-36209, JP-A-53-362223.
And trihalomethyl-2-pyrone described in JP-A No. 6-55, and o-naphthoquinonediazide-4-sulfonic acid chloride described in JP-A-55-6244 and phenols having an electron-withdrawing substituent. Or an ester compound or amide compound with aniline acid, JP-A-55-77742, JP-A-57-
Examples thereof include halomethylvinyloxadiazole compounds and diazonium salts described in JP-A-148784.

As the above-mentioned organic dye, Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.), Patent Pure Blue (manufactured by Sumitomo Mikuni Chemical Co., Ltd.), Oil Blue # 603 (manufactured by Orient Chemical Industry Co., Ltd.) , Sudan Blue II (manufactured by BASF), Crystal Violet, Malachite Green, Fuchsin, Methyl Violet, Ethyl Violet, Methyl Orange, Priliant Green, Congo Red, Eosin, Rhodamine 6
6 etc. can be mentioned. In addition to the above materials, a plasticizer, a surfactant, an organic acid, an acid anhydride and the like can be added to the photosensitive composition, if necessary.

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

Each of these components was dissolved in the following solvent,
By coating and drying on the surface of the support used in the present invention, a photosensitive layer can be provided to produce the photosensitive lithographic printing plate of the present invention. As a solvent that can be used when dissolving the photosensitive composition used in the present invention, 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, Propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, dimethylformamide, dimethyl sulfoxide, dioxane, acetone, methyl ethyl ketone, cyclohexanone, methyl Cyclohexanone, diacetone Alcohol, acetylacetone,
Examples include r-butyrolactone. These solvents are
They can be used alone or in combination of two or more.

The coating method used when the photosensitive composition used in the present invention is coated on the surface of a support is a conventionally known method, for example, spin coating, wire bar coating, dip coating, air knife coating, roll coating. , Blade coating, curtain coating and the like are used. At this time, the coating amount varies depending on the application, but is, for example, 0.05 to 5.0 g as solid content.
A coating amount of / m ² is preferred. In using the photosensitive lithographic printing plate thus obtained, a conventionally used method can be applied, for example, a transparent original image having a line image, a halftone dot image, etc. is exposed in close contact with the photosensitive surface, Then, the relief image is obtained by removing the photosensitive layer in the non-image area with an appropriate developing solution. As a light source suitable for exposure, a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a carbon arc lamp or the like is used, and a developer used for the development is preferably an alkaline aqueous solution, for example, sodium silicate or potassium silicate. , Aqueous solutions of sodium hydroxide, potassium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, sodium carbonate, potassium carbonate and the like. The concentration of the alkaline aqueous solution at this time varies depending on the type of the photosensitive composition and the alkali, but is generally 0.1-10.
The range of wt% is appropriate, and an organic solvent such as a surfactant or alcohol can be added to the acid-alkali aqueous solution, if necessary.

[0044]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Examples 1 to 4 [Preparation of Supports 1 to 4] A 0.3 mm thick aluminum plate (material 1050, temper H16) was degreased in a 3% aqueous sodium hydroxide solution, and then 1% hydrochloric acid was added. Electrolytic etching treatment was performed in an aqueous solution. Then, after desmutting treatment with a 1% sodium hydroxide aqueous solution, anodizing treatment was performed in a 40% sulfuric acid aqueous solution. The aluminum plate treated as described above was immersed in an aqueous solution under the following conditions at 90 ° C. for 10 seconds. After washing with water, it was dried at 95 ° C. for 3 minutes.

[0046]

[Table 1]

[Samples I-1 to I-4 of the photosensitive lithographic printing plate]
Preparation] The coating solution (I) of the photosensitive composition having the following composition was applied to the supports 1 to 4 prepared as described above using a wire bar and dried at 80 ° C for 2 minutes. Sample I-1 of a photosensitive lithographic printing plate having a dry coating film thickness of 2.2 g / m ^2.
~ I-4 was obtained.

[Coating Liquid (I) of Photosensitive Composition]

[Table 2] Novolac resin * A 6.7 g o-quinonediazide compound * B 1.5 g Surfactant * C 0.2 g Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.08 g Compounds that generate halogen free radicals * D 0.15g Methyl Cellosolve 100ml

Then, using a 2 kW metal halide lamp as a light source, the photosensitive lithographic printing plate obtained was 8 mW.
Exposure was carried out by irradiating at 60 / cm ² for 60 seconds. This exposed photosensitive lithographic printing plate was used as a commercially available developer (SD-32, manufactured by Konica Corporation, diluted 5 times, and developed for 30 hours).
Second, development temperature 25 ° C.), and developed as a planographic printing plate sample I ′.
-1 to I'-4 were obtained. The following compounds were used as the compounds of * A to * D.

* A: Novolac resin [phenol and m-
Copolycondensation resin of cresol, p-cresol and formaldehyde (the molar ratio of each of phenol, m-cresol and p-cresol is 2.0: 4.8: 3.2,
w = 6,500, Mw / Mn = 5.4)]]

* B: o-quinonediazide compound

[0052]

[Chemical 3]

* C: Surfactant Emulgen 120 (polyoxyethylene lauryl ether, manufactured by Kao Corporation)

* D: Compound that produces a halogen free radical 2-trichloromethyl-5- (p-methoxystyryl)
-1,3,4-oxadiazole (compound described in Example 1 of JP-A-54-74728)

Comparative Examples 1 and 2 [Production of Supports 5 to 7] Supports 1 to 4 except that the following aqueous solutions were used in place of the aqueous sodium nitrite solutions in the production of Supports 1 to 4 5-7 were obtained.

[0056]

[Table 3]

[Preparation of Photosensitive Lithographic Printing Plate Samples I-5 to 7] Photosensitive lithographic printing plate samples I-1 to 4 were prepared in the same manner as in Photosensitive lithographic printing plate samples I-1 to 4 except that the above-mentioned Supports 5 to 7 were used. Plate samples I-5 to 7 were prepared. These samples were exposed and developed in the same manner as in the case of the photosensitive lithographic printing plate samples I'-1 to 4 to obtain lithographic printing plate samples I'-5 to 7. The obtained planographic printing plate samples I′-1 to I′-7 were evaluated using the evaluation methods described below. The obtained results are shown in Table 1.

[0058]

[Table 4]

[Evaluation Method] (Staining Test Due to Residual Film) After forming 5 (5 mm × 15 cm) image areas on the lithographic printing plate obtained under the exposure and development conditions described above, an erasing liquid (SIR-15) was used. The image part was erased by Konica Corporation. There are 5 levels of erasing time (Table 1
), And the fringe stain due to the erasing at that time was confirmed by applying a developing ink (SOP-1 manufactured by Konica). Evaluation: ○ ・ ・ Good △ ・ ・ Erasing marks appear (ink is not inked but can be visually confirmed) × ・ ・ Stains (ink is directly inked)

(Development Solution Corrosion Resistance) With respect to the lithographic printing plate obtained under the above-mentioned exposure and development conditions, the state of white dusting of aluminum hydroxide due to corrosion of the back surface was visually evaluated. Evaluation: ○ ・ ・ Not observed at all △ ・ ・ Slightly whitish × ・ ・ Strongly whitish

[0061]

EFFECT OF THE INVENTION The photosensitive lithographic printing plate of the present invention has excellent developability, good water retention in non-image areas, and excellent developer corrosion resistance.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tatsunori Tsuchiya 14 Sunayama, Hasaki-cho, Kashima-gun, Ibaraki Mitsubishi Kasei Co., Ltd. Kashima Plant (72) Inventor Koji Tomita 1 Sakura-cho, Hino, Tokyo Konica Stock Company (72) Inventor Hideyuki Nakai, Konica Co., Ltd., 1 Sakura-cho, Hino-shi, Tokyo (72) Shinichi Matsubara, 1 Sakura-cho, Hino-shi, Tokyo Konica, Co. Ltd.

Claims (1)

[Claims] 1. A surface of a support subjected to at least roughening and anodization in this order is treated with an aqueous nitrite solution,
A photosensitive lithographic printing plate provided with a photosensitive layer, wherein the aqueous nitrite solution has a pH of 8.0 to 11.0.