JPH11190902A - Method for preparing lithographic printing plate and heat mode recording lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a printing plate prevented from occurrence of stains on nonimage parts at the time of printing and high in sensitivity and good in storage stability and capable of executing digital recording with laser beams by coating a support with an image forming layer containing an o- quinonediazido compound and an infrared absorber. SOLUTION: The heat mode recording lithographic printing plate provided on the support with the image forming layer containing an o-quinonediazido compound and an infrared absorber is formed by imagewise exposing or heating it with laser beams, and then, wholly exposing it to ultraviolet rays and developing it with an aqueous developing solution. An infrared absorbing dye in the wavelength region of >=700 nm and a carbon black and a magnetic power and the like are used for the infrared absorber. As the o-quinonediazido compound to be used, an ester compound of the o-quinonediazido compound with a polycondensation resin of phenols with aldehydes or ketones is exemplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-mode recording lithographic printing plate capable of digital recording using a laser and a method for producing a lithographic printing plate.

[0002]

BACKGROUND OF THE INVENTION In recent years, it has been practiced to form a lithographic printing plate by digitally forming an image using a laser. For example, WO 96/20429 discloses that a heat mode recording lithographic printing plate in which an ester of naphthoquinonediazide and a phenolic resin or a mixture of an o-quinonediazide esterified product and a phenolic resin is coated on a support is exposed entirely to ultraviolet light. A heat mode recording method in which an image is exposed by an infrared laser and a portion other than the laser exposed portion is removed by a developer is described.

The principle of this image forming process is described in WO96.
No. / 20429, which utilizes the phenomenon that an o-quinonediazide compound becomes indenecarboxylic acid when exposed to ultraviolet light, and becomes insoluble in a developing solution when heated.

Japanese Patent Application Laid-Open No. 7-43894 discloses that
It has an o-quinonediazide compound and a specific chemical structure containing nitrogen in the molecule, and has a maximum absorption wavelength of 680 to 125.
0 nm selected from cyanine dye, azurenium dye, squarium dye, croconium dye, quinone dye, thiazine dye, xanthene dye,
An image forming material provided on a support is entirely exposed to a composition containing an additive which reacts with a photoreaction product of an o-quinonediazide compound by heating to form an alkali insoluble material, using actinic rays, and A method is described in which an image is formed by irradiating a laser beam and removing a non-irradiated area of the laser beam using an alkaline developer.

However, the lithographic printing plate prepared by these methods has a disadvantage that the non-image portion is easily stained during printing because a residual film is easily formed on the non-image portion and a dye residue is easily generated. Was. In particular, if it takes a long time to develop after the entire surface is exposed, the stain on the non-image portion becomes remarkable. Also,
In particular, the infrared absorbing dye described in JP-A-7-43894 has a disadvantage that a strong dye remains in a non-image area.

Further, as a material recordable by infrared rays and ultraviolet rays, US Pat. No. 5,340,699 discloses an acid generator, a resole resin, a novolak resin and an infrared absorbing dye, and the exposed portion is cured. However, the composition which is insoluble in a developing solution and becomes an image portion is described, but has a disadvantage that storage stability is poor.

Thus, the present inventor studied and found that o-
In a heat mode recording planographic printing plate having an image forming layer containing a quinonediazide compound and an infrared absorbing substance, the above-mentioned drawbacks can be eliminated by performing scanning exposure with a laser beam before performing full-surface exposure with ultraviolet rays. There was found. Further, by containing an infrared absorbing dye selected from a pyrylium dye, a thiopyrylium dye, a thiol nickel complex salt dye, a mercaptophenol complex salt dye, and a mercapton naphthol complex salt dye containing no nitrogen atom in the molecule in the image forming layer, As described above, it has been found that the above-mentioned disadvantages can be solved even when the image is formed by exposing the entire surface with ultraviolet rays, then exposing the image with an infrared laser, and removing portions other than the laser exposed portion with a developing solution.

[0008]

Accordingly, the present invention provides:
Provided is a heat-mode recording planographic printing plate and a method for preparing a planographic printing plate that have no sensitivity to non-image portions during printing, have excellent sensitivity, have good storage stability, and can perform digital recording using a laser. Is to do.

[0009]

The object of the present invention is to provide (1) a heat mode recording lithographic printing plate having an image forming layer containing an o-quinonediazide compound and an infrared absorbing substance on a support, A method for preparing a lithographic printing plate, comprising exposing or heating with an imagewise laser beam, exposing the entire surface to ultraviolet rays, and developing with an aqueous developer. (2) The method for preparing a lithographic printing plate as described in (1) above, wherein the image forming layer contains a phenolic OH group-containing resin. (3) The image forming layer contains at least one compound selected from an amine compound, a spiro compound, an imidazole compound, a quaternary ammonium compound, urea, thiourea and derivatives thereof, an acid dye, a pyridine ring compound and an amide compound. The method for preparing a lithographic printing plate as described in (1) or (2) above, wherein (4) an o-quinonediazide compound on a support and (b) a pyrylium dye containing no nitrogen atom in the molecule,
A heat mode recording planographic printing plate comprising an image forming layer containing at least one infrared absorbing dye selected from a thiopyrylium dye, a thiol nickel complex dye, a mercaptophenol complex salt dye, and a mercaptonaphthol complex salt dye. (5) The heat mode recording lithographic printing plate as described in (4) above, wherein the image forming layer contains a phenolic OH group-containing resin. (6) The image forming layer contains at least one compound selected from an amine compound, a spiro compound, an imidazole compound, a quaternary ammonium compound, urea, thiourea and derivatives thereof, an acid dye, a pyridine ring compound and an amide compound. (4) or (5) above,
The heat mode recording lithographic printing plate described in 1. (7) The heat-mode recording lithographic printing plate according to any one of the above (4) to (6) is subjected to full-surface exposure with ultraviolet light and imagewise laser light exposure or heating, and is developed with an aqueous developer. A method for producing a lithographic printing plate as a feature. Achieved by

Hereinafter, the present invention will be described in detail.

First, a heat mode recording planographic printing plate comprising an image forming layer containing an o-quinonediazide compound and an infrared absorbing substance on a support of the present invention will be described.

[0012] As the infrared absorbent, a wavelength of 700 n
m, an infrared absorbing dye having an absorption of at least m, carbon black,
Magnetic powder or the like can be used. A particularly preferred infrared absorbing dye is an infrared absorbing dye having an absorption peak at 700 to 1200 nm and a molar extinction coefficient ε at the peak of 10 ⁵ or more.

The above-mentioned infrared absorbing dyes include cyanine dyes, squarium dyes, croconium dyes, azurenium dyes, phthalocyanine dyes, naphthalocyanine dyes, polymethine dyes, naphthoquinone dyes, thiopyrylium dyes, dithiol metal dyes Complex dyes, anthraquinone dyes, indoaniline metal complex dyes, intermolecular CT dyes, aminium dyes, diimmonium dyes, pyrylium dyes, thiol nickel complex dyes, mercaptophenol complex salt dyes, mercaptonaphthol complex salt dyes, and the like. As external absorption dyes, pyrylium dyes containing no nitrogen atom in the molecule, thiopyrylium dyes,
When using a thiol nickel complex dye, mercaptophenol complex salt dye, or mercaptonaphthol complex salt dye, after exposing imagewise with laser light, exposing the whole surface with ultraviolet light and developing with an aqueous developer, As described above, after the entire surface is exposed to ultraviolet light, the image is exposed to an infrared laser, and even when the portion other than the laser exposed portion is removed with a developing solution, defects in the conventional heat mode recording lithographic printing plate can be improved. It is preferred.

The infrared absorbing dyes further include JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, and 1-28075.
No. 0, No. 1-293342, No. 2-2074
JP-A-3-26593, JP-A-3-30991, JP-A-3-34891, JP-A-3-36093, JP-A-3-36094, JP-A-3-36095, and JP-A-3-42281 And the compounds described in JP-A Nos. 3-103476 and 3-103476.

As the infrared absorber, the following general formula (1)
The cyanine dye represented by is preferably used.

[0016]

Embedded image In the general formula (1), (X) represents an ion necessary to cancel the charge of the molecule, and n represents a number necessary to neutralize the total charge of the molecule. N is 0 when an internal salt is formed. Examples of counter ions include Cl ⁻ , B
_{^{r -, ClO - 4, BF}} - 4, include alkylboron arsenide of t- butyl triphenyl borate arsenide.

In the general formula (1), A represents a conjugated carbon atom having 5 to 13 carbon atoms. In the case where a laser emitting infrared rays is used as a light source for image exposure, it is preferable to select an effective number of carbon atoms for the conjugated carbon atoms in accordance with the transmission wavelength of the laser. For example, when using a YAG laser having an emission wavelength of 1060 nm, a conjugated carbon atom having 9 to 13 carbon atoms is preferable.
This conjugated carbon atom has a hydrogen atom or any substituent. In addition, the conjugate bond may form a ring with a substituent.

In the general formula (1), the ring formed by Z ₁ and the ring formed by Z ₂ may have a condensed ring, and may have any substituent. As a substituent, a halogen atom, an alkyl group having 1 to 5 carbon atoms,
An alkoxy group having 1 to 5 carbon atoms, -SO ₃ M and a single C
A group selected from OOM (M is a hydrogen atom or an alkali metal atom) is preferable.

Y ₁ and Y ₂ each represent an optional substituent. Preferred substituents are an alkyl group or an alkoxy group having 1 to 5 carbon atoms;-[(CH ₂ ) _n -O] _k- (CH ₂ )
_m OR (n and m are each an integer of 1 to 3, k is 0 or 1,
R represents an alkyl group having 1 to 5 carbon atoms. ); -R-
SO ₃ M (R is an alkylene group having 1 to 5 carbon atoms, M represents an alkali metal atom.); - R-COOM ( R is an alkylene group having 1 to 5 carbon atoms, M represents an alkali metal atom )). Y ₁ and Y ₂ are preferably the above-mentioned —R—SO ₃ M or —R-COOM which forms an internal salt from the viewpoint of sensitivity and developability.

The cyanine dye represented by the general formula (1) is
When a semiconductor laser is used as a light source for image exposure, it preferably has an absorption peak at 750 to 900 nm, and when a YAG laser is used, has an absorption peak at 900 to 1200 nm, and has a molar absorption coefficient of ε> 1 × 10 ⁵ .

In the present invention, the amount of the infrared absorber added is preferably in the range of 0.5 to 15% by weight. Addition amount is 1
If it exceeds 5% by weight, the developability of the non-image area (exposed area) decreases, and if it is less than 0.5% by weight, the development resistance of the image area decreases.

Representative specific examples of the infrared absorber (including the cyanine dye represented by the general formula (1)) preferably used in the present invention are shown below, but are not limited thereto.

[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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These dyes can be synthesized by known methods, but the following commercially available products can also be used.

Nippon Kayaku: IR750 (anthraquinone type); IRG002, IRG003 (aminium type);
IR820 (polymethine type); IRG022, IRG0
33 (diimonium-based); CY-2, CY-4, CY-
9, CY-20 Mitsui Toatsu: KIR103, SIR103 (phthalocyanine); KIR101, SIR114 (anthraquinone); PA1001, PA1005, PA1006, S
IR128 (metal complex type) Dainippon Ink and Chemicals: Fastogen blue 812
0 Midori Kagaku: MIR-101, MIR-1011, MI
R-1021 Japanese photosensitive dye: NKX-113 (Exemplified compound 1-52)
(Metal complex type), NK-3508 (Exemplified compound 1-5)
3), NK3509 (exemplified compound 1-54), NK-3
519 (exemplified compound 1-55) (pyrylium compound), NK
-2545 (cyanine-based) Other commercially available from companies such as Sumitomo Chemical and Fuji Photo Film.

Next, the o-quinonediazide compound will be described.

The o-quinonediazide compound is a compound having an o-quinonediazide group in the molecule. Examples of the o-quinonediazide compound that can be used in the present invention include an o-naphthoquinonediazide compound, for example, o-quinonediazide compound. Ester compounds of a polycondensation resin of naphthoquinonediazidesulfonic acid with phenols and aldehydes or ketones.

Examples of the phenol in the polycondensation resin with the phenol and aldehyde or ketone include phenol, o-cresol, m-cresol,
Examples include monohydric phenols such as p-cresol, 3,5-xylenol, carvacrol, and thymol; dihydric phenols such as catechol, resorcinol, and hydroquinone; and trihydric phenols such as pyrogallol and phloroglucin. As the aldehyde, for example, formaldehyde,
Examples include benzaldehyde, acetaldehyde, crotonaldehyde, furfural and the like. Preferred among these are formaldehyde and benzaldehyde. Examples of the ketone include acetone, methyl ethyl ketone, and the like.

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

In the above-mentioned o-naphthoquinonediazide compound, the condensation rate of o-naphthoquinonediazidesulfonic acid to OH groups of phenols (reaction rate for one OH group) is preferably 15% to 80%, more preferably 2%.
0% to 45%.

Further, examples of the o-quinonediazide compound used in the present invention include the following compounds described in JP-A-58-43451. That is, for example, 1,2-benzoquinonediazidosulfonic acid ester, 1,2-naphthoquinonediazidosulfonic acid ester, 1,2-benzoquinonediazidosulfonic acid amide,
Known 1,2-quinonediazide compounds such as 1,2-naphthoquinonediazidesulfonic acid amide, more specifically, "Light-Sensitive Systems" No. 339, by J. Kosar. ~ 352 (1965), John Willie
John Willey & Sons (New York) and W.S.
orest), Photoresist, Vol. 50 (1975), McGraw Hill (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-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-naphthoquinonediazido-5-sulfonyl) -aniline, 2 '-(1,2-naphthoquinonediazido-5-sulfonyloxy) -1-hydroxy-anthraquinone,
1,2-naphthoquinonediazide-5-sulfonic acid-2,
2-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
Of 1,4-naphthoquinonediazide-5-sulfonic acid chloride with 1 mol of purpurogallin, 1,2 mol of the compound with 1 mol of 4,4'-dihydroxy-1,1'-diphenylsulfonic acid. -Naphthoquinonediazide-
Examples thereof include 1,2-quinonediazide compounds such as 5- (N-dihydroabiethyl) -sulfonamide. In addition, Japanese Patent Publication Nos. 37-1953 and 37-3627
Nos. 37-13109, 40-26126, 40-3801, 45-5604, and 45-27
No. 345, No. 51-13013, JP-A-48-965.
Nos. 75, 48-63802, and 48-63803 can also include the 1,2-quinonediazide compounds described in JP-A-75-63802 and JP-A-48-63803.

In the present invention, as the o-quinonediazide compound, a 1,2-naphthoquinonediazide-4-sulfonic acid ester compound is more preferable than a 1,2-naphthoquinonediazide-5-sulfonic acid ester compound.

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

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

A binder can be used in the image forming layer of the present invention. As the binder, for example, a high molecular weight binder can be used. Examples of the high molecular weight binder include a novolak resin, a polymer having a hydroxystyrene unit, a polymer having a structural unit represented by the following general formula (4), and other known acrylic resins.

[0049]

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[Wherein, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group, or a carboxylic acid group, R ₃ represents a hydrogen atom, a halogen atom, or an alkyl group, and R ₄ represents a hydrogen atom, an alkyl group, Represents an aryl group.

Y represents an arylene group which may have a substituent.

X represents a divalent organic group connecting the nitrogen atom and the carbon atom of the arylene group, and n represents an integer of 0 to 5. Examples of the novolak resin include phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde copolycondensate resin described in JP-A-55-57841, and JP-A-55-578. And a copolycondensate resin of p-substituted phenol and phenol or cresol and formaldehyde as described in JP-A-127553.

Examples of the polymer having a hydroxystyrene unit include polyhydroxystyrene and hydroxystyrene copolymer described in JP-B-52-41050.

The polymer having the structural unit represented by the general formula (4) may be a homopolymer having a repeating structure of only the structural unit or an unsaturated polymer of the structural unit and another vinyl monomer. It is a copolymer in which one or more structural units represented by a structure in which a double bond is cleaved are combined.

In the general formula (4), examples of the alkyl group represented by R ₁ and R ₂ include a methyl group and an ethyl group. Preferred as R ₁ and R ₂ is a hydrogen atom.

Examples of the halogen atom represented by R ₃ include a chlorine atom and a bromine atom, and examples of the alkyl group include a methyl group and an ethyl group. R ₃
Is preferably a hydrogen atom or a methyl group.

The alkyl group represented by R ₄ includes, for example, a methyl group and an ethyl group, and the aryl group includes, for example, a phenyl group or a naphthyl group.

Y represents an arylene group which may have a substituent, and examples of the arylene group include a phenylene group and a naphthylene group. Examples of the substituent of the arylene group include an alkyl group such as a methyl group and an ethyl group, a halogen atom such as a chlorine atom and a bromine atom, a carboxylic acid group, a methoxy group, an alkoxy group such as an ethoxy group, a hydroxyl group, a sulfonic acid group, Examples include a cyano group, a nitro group, and an acyl group.
Preferred as Y is an arylene group having no substituent or substituted with a methyl group.

Examples of the divalent organic group connecting the nitrogen atom represented by X and the aromatic carbon atom include an oxygen atom. n is preferably 0.

The polymer having the structural unit represented by the general formula (4) is more specifically described, for example, in the following (a) to (a).
A copolymer represented by (h), such as a homopolymer or a random copolymer.

[0061]

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In (a) to (h), R _{5 to} R ₉ each represent a hydrogen atom, an alkyl group, or a halogen atom;
Represents an alkyl group or a halogen atom. Also, m, n,
1, k and s represent mol% of each structural unit.

As the binder used in the image forming layer of the present invention, a resin having a phenolic OH group, such as a polymer having a hydroxystyrene unit or a polymer having a structural unit represented by the general formula (4), is used. Is preferred. In particular, a resin having a phenolic OH group, when combined with a quinonediazide compound, tends to have a difference in exposure solubility.

A novolak resin, a polymer having a hydroxystyrene unit, a polymer having a structural unit represented by the general formula (4), and an acrylic resin can also be used in combination.

Further, a lipophilic resin can be added to the image forming layer of the present invention in order to improve the oil sensitivity of the image forming layer.

As the lipophilic resin, for example, those described in
A condensate of a phenol substituted with an alkyl group having 3 to 15 carbon atoms and an aldehyde, for example, a t-butylphenol formaldehyde resin described in JP-A-125806 can be used.

In the image forming layer of the present invention, an amine compound, a spiro compound, an imidazole compound, a quaternary ammonium compound, urea, thiourea and derivatives thereof, an acid dye, a pyridine ring compound, an amide It is preferable to include at least one compound selected from the compounds.

Examples of the amine compound include triethanolamine, diethylaniline, hexamethylenetetramine and the like.

As the spiro compound, spiro [3.5]
Nonane, spirodicyclopentane and the like can be mentioned.

Examples of the imidazole compound include imidazole, 1-methylimidazole, 1,3-dimethylimidazole and the like.

Examples of the quaternary ammonium compound include a tetraalkylammonium compound and a trialkylarylammonium compound.

Examples of urea, thiourea and derivatives thereof include urea, ethyl urea, dimethylol urea, thiourea, ethylene urea and the like as described in JP-A-2-141751.

As the acid dye, JP-A-2-14175
No. 2, azo dyes, anthraquinone dyes, carbonium dyes, and the like, as described in JP-A-2.

As the pyridine ring compound, JP-A No. 2-1
Pyridine, as described in US Pat.
2-methylpyridine, 2-ethylpyridine and the like can be mentioned.

As the amide compound, acetamide, p
-Aminoacetanilide and the like.

In the image forming layer of the present invention, if necessary,
Dyes, pigments, sensitizers, and the like other than those described above can be contained.

The heat mode recording planographic printing plate of the present invention
It can be obtained by dissolving each of the above components in a solvent that dissolves them, applying them to the surface of a suitable support, and drying.

Examples of the solvent include propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, dimethylformamide, dimethyl sulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, methyl ethyl ketone and the like. No. These solvents are used alone or in combination of two or more.

As the coating method, conventionally known methods, for example, spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, and curtain coating can be used. The amount of application varies depending on the application, but is preferably, for example, 0.5 to 5.0 g / m ² as a solid content.

As the support, aluminum, zinc,
Metal plates such as steel, copper, etc., and metal plates, paper, plastic films and glass plates plated or deposited with chromium, zinc, copper, nickel, aluminum, iron, etc., paper coated with resin, metal foil such as aluminum Paper, hydrophilic plastic film, or the like can be used.

For the support, it is preferable to use an aluminum plate (including an alloy plate) which has been subjected to surface treatment such as graining treatment, anodic oxidation treatment and, if necessary, sealing treatment. A known method can be applied to these processes.

Examples of the graining method include a mechanical method and an electrolytic etching method. Examples of the mechanical method include a ball polishing method, a brush polishing method, a polishing method using liquid honing, and a buff polishing method. The various methods described above can be used alone or in combination depending on the composition of the aluminum material and the like.

In the etching by electrolysis, phosphoric acid, sulfuric acid,
The reaction is performed using a bath in which an inorganic acid such as hydrochloric acid or nitric acid is used alone or in combination of two or more. After the graining treatment, if necessary, a desmut treatment is performed with an aqueous solution of an alkali or an acid to neutralize and wash with water.

The anodic oxidation treatment is carried out by using a solution containing one or more of sulfuric acid, chromium, oxalic acid, phosphoric acid, malonic acid and the like as an electrolytic solution, and performing electrolysis using an aluminum plate as an anode. The amount of the formed anodic oxide film is appropriately 1 to 50 mg / dm ² , preferably 1 to 50 mg / dm ^2.
0 to 40 mg / dm ² , particularly preferably 25 to 4 mg / dm ^2.
0 mg / dm ² . The amount of the anodic oxide coating can be determined, for example, by coating an aluminum plate with a chromic acid phosphate solution (phosphoric acid 85% solution:
35 ml, prepared by dissolving 20 g of chromium (IV) oxide in 1 liter of water), dissolving the anodic oxide film, and measuring the weight change before and after dissolving the anodic oxide film. Can be.

The sealing treatment includes boiling water treatment, steam treatment,
Specific examples include sodium silicate treatment and aqueous dichromate treatment.

Further, the aluminum support may be subjected to an undercoating treatment with an aqueous solution of a water-soluble polymer compound or a metal salt such as fluorinated zirconic acid.

In the method of preparing a lithographic printing plate according to the present invention, the heat-mode recording lithographic printing plate is exposed or heated with a laser beam in an image-wise manner, then exposed entirely with ultraviolet rays, and developed with an aqueous developer. You.

As the laser light source, a semiconductor laser,
He-Ne laser, YAG laser, carbon dioxide laser and the like can be mentioned. An output of 50 mW or more is appropriate.
Preferably, it is 100 mW or more.

The irradiated laser light is converted from light to heat and heats the image forming layer. Instead of scanning exposure with laser light, it is also possible to form an image by heating imagewise using a thermal printer or the like.

As the infrared absorbing material, at least one infrared absorbing dye selected from pyrylium dyes, thiopyrylium dyes, thiol nickel complex dyes, mercaptophenol complex salt dyes, and mercaptonaphthol complex salt dyes having no nitrogen atom in the molecule is used. Heat mode recording lithographic printing plate, after exposing with laser light like an image,
The entire surface may be exposed to ultraviolet light and developed with an aqueous developer to form an image.However, after the entire surface is exposed to ultraviolet light, the image is exposed to laser light and developed using an aqueous developer. An image may be formed. Also, instead of exposure with laser light,
The image may be heated by using a thermal printer or the like to form an image.

A mercury lamp or the like can be used as a light source for the entire exposure with ultraviolet light.

As a developer used for developing the heat mode recording planographic printing plate of the present invention, an aqueous alkali developer is preferable. Examples of the aqueous alkaline developer include aqueous solutions of alkali metal salts such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, dibasic sodium phosphate, and tertiary sodium phosphate. No. The concentration of the alkali metal salt in the aqueous alkaline developer is 0.05 to
A range of 20% by weight is suitable, and more preferably a range of 0.1% by weight.
1 to 10% by weight.

If necessary, a surfactant such as an anionic surfactant or an amphoteric surfactant, or an organic solvent such as alcohol can be added to the developer.

As the organic solvent, propylene glycol, ethylene glycol monophenyl ether, benzene alcohol, n-propyl alcohol and the like are useful.

[0095]

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

Example 1 Preparation of Support A 0.24 mm thick aluminum plate (material: 1050, tempered H16) was degreased in a 5% aqueous sodium hydroxide solution at 60 ° C. for 1 minute, and then 0.5 mol / mol temperature, 25 ° C., current density; 60 A / dm ² , treatment time;
Electrolytic etching was performed under the condition of 0 second. Then 5
After a desmut treatment at 60 ° C. for 10 seconds in a 20% aqueous solution of caustic soda, an anodic oxidation treatment is carried out in a 20% sulfuric acid solution under the conditions of temperature: 20 ° C., current density: 3 A / dm ² , treatment time: 1 minute. Was. Further, a hot water sealing treatment was performed with hot water of 30 ° C. for 20 seconds to produce an aluminum support.

On this aluminum support, a coating solution having the following composition was applied so as to have a dry film thickness of 2 g / m ^2.
Dried at 1 ° C for 1 minute, heat mode recording lithographic printing plate sample 1
Was prepared.

<Coating Liquid Composition> Esterified product of p-cresol novolak resin and 1,2-naphthoquinonediazide-4-sulfochloride (esterification rate: 50%) 34 parts by weight Phenol, m-cresol, p-cresol (5 : 57:38) and copolycondensation resin of formaldehyde (Mw 3700) 73 parts by weight Acrylic resin (Binder A) 15 parts by weight

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Pyrylium dye (Exemplified compound 1-53) 12 parts by weight Methyl cellosolve 906 parts by weight Further, instead of pyrylium dye (NK-3508, manufactured by Nippon Kogaku Dyeing Co., Ltd.) (Exemplified compound 1-53), pyrylium dye (NK- 3509, Nippon Kogaku Dye Co., Ltd. (Exemplary Compound 1-54), pyrylium dye (NK-3519, Nippon Kogaku Dye Co., Ltd.) (Exemplary Compound 1-55), metal complex dye (NKX-113, Nippon Kogyo Dye Co., Ltd.) ) (Exemplified compound 1-52), aminium dye (NK-2545, manufactured by Tokyo Institute of Technology) (exemplified compound 1-51), aminium dye (IRG-002, manufactured by Nippon Kayaku Co., Ltd.), diimonium dye (IRG-022, Nippon Kayaku), cyanine dye (CY-10, manufactured by Nippon Kayaku), cyanine dye (CY
-17, manufactured by Nippon Kayaku Co., Ltd.), cyanine dye (NK-20)
14, Nippon Kogaku Dye Co., Ltd.), cyanine dye (NK-2)
612, manufactured by Nippon Kogaku Dye Co., Ltd., pyrylium dye (NK
Heat mode recording planographic printing plate sample 2 except that -3027, Nippon Kogaku Dye Co., Ltd.) and a pyrylium dye (NK-2677, Nippon Kogaku Dye Co., Ltd.) were used. 13 was produced. Further, a heat mode recording planographic printing plate sample 14 was prepared in the same manner as in the heat mode recording planographic printing plate sample 1 except that the pyrylium dye was omitted.

The dyes used for each sample are as shown in Table 1.

[0102]

[Table 1] With respect to the obtained Samples 1 to 14, an image was formed by an image forming process shown in Table 2, a lithographic printing plate was prepared, and fine line reproducibility, A2 exposure time, printing stain,
The shelf life was evaluated. Table 2 shows the obtained results.

[0103]

[Table 2]

<< Conditions in Image Forming Process >><YAG Laser Exposure> YAG laser (wavelength 1060)
(nm, output: 500 mW) and exposure at 2000 dpi. <Semiconductor laser exposure> Semiconductor laser (wavelength 830n)
m, output: 150 mW) and exposure at 2000 dpi.

<Overall Exposure> Exposure was performed with a 4 kW metal halide lamp from a distance of 50 cm for 20 seconds. <Development> Developing solution: 6-fold dilution of Konica PS plate developing solution SDR-1 Developing condition: 27 ° C., 25 seconds (washing with water 15 seconds) <Heating> Heat treatment was performed at 120 ° C. for 30 seconds using an infrared heater.

<< Fine line reproducibility, A2 exposure time, print stain,
Method for evaluating storage stability><Fine line reproducibility> Among reproducible line widths, 4 μm to 50 μm
Was evaluated with a thin line. <A2 exposure time> The time required for an A2 size sample using an outer surface scanning type exposure machine for a semiconductor laser and an inner surface scanning type exposure machine for a YAG laser.

<Print Stain> The sample on which an image was formed was printed by a printing machine, and the stain on the non-image portion was visually observed and evaluated according to the following evaluation criteria. ；: No stain on non-image part ○ △: Stain on non-image part can be understood only by paying careful attention △: Stain on non-image part is clearly visible △ ×: Non-image part is considerably dirty ×: Printed matter The entire surface is dirty

<Storability> An image was formed using a sample stored at 55 ° C. for 3 days, the sample on which the image was formed was printed by a printing machine, and the stain on the non-image area was visually observed. Was evaluated. ；: No stain on non-image part ○ △: Stain on non-image part can be understood only by paying careful attention △: Stain on non-image part is clearly visible △ ×: Non-image part is considerably dirty ×: Printed matter The entire surface is dirty

[0109]

According to the method for producing a lithographic printing plate of the present invention, it is possible to obtain a lithographic printing plate in which the non-image area has no stain during printing. Further, a heat mode recording planographic printing plate containing a pyrylium dye containing no nitrogen atom in the molecule in the image forming layer of the present invention, a thiopyrylium dye, a thiol nickel complex dye, a mercaptophenol complex salt dye, and a mercaptonaphthol complex salt dye, Irrespective of the forming method, a lithographic printing plate free from contamination of non-image areas at the time of printing, having excellent sensitivity and good storability and capable of digital recording using a laser can be obtained.

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI G03F 7/38 511 G03F 7/38 511

Claims (7)

[Claims] 1. A heat-mode recording lithographic printing plate having an image-forming layer containing an o-quinonediazide compound and an infrared absorbing substance on a support is exposed or heated imagewise with a laser beam, and then exposed to ultraviolet light. A method for preparing a lithographic printing plate, comprising: exposing the entire surface of the substrate to light and developing with an aqueous developer. 2. The method according to claim 1, wherein the image forming layer contains a phenolic OH group-containing resin. 3. An image forming layer comprising at least one compound selected from an amine compound, a spiro compound, an imidazole compound, a quaternary ammonium compound, urea, thiourea and derivatives thereof, an acid dye, a pyridine ring compound and an amide compound. The method for preparing a lithographic printing plate according to claim 1, wherein 4. A support selected from (a) an o-quinonediazide compound and (b) a pyrylium dye, a thiopyrylium dye, a thiol nickel complex salt dye, a mercaptophenol complex salt dye, and a mercaptonaphthol complex dye on a support. A heat-mode recording lithographic printing plate comprising an image forming layer containing at least one infrared absorbing dye. 5. The lithographic printing plate according to claim 4, wherein the phenolic OH group-containing resin is contained in the image forming layer. 6. The image forming layer, wherein at least one compound selected from an amine compound, a spiro compound, an imidazole compound, a quaternary ammonium compound, urea, thiourea and derivatives thereof, an acid dye, a pyridine ring compound and an amide compound. 6. The composition according to claim 4, wherein
The heat mode recording lithographic printing plate described in 1. 7. A heat-mode recording lithographic printing plate according to any one of claims 4 to 6, wherein the lithographic printing plate is subjected to an entire surface exposure with ultraviolet rays and an imagewise laser beam exposure or heating, and developed with an aqueous developer. The method of preparing a lithographic printing plate.