JP2001051404A - Plate making process for planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate making process for producing a planographic printing plate free from a deposit inadequate to the printing plate on the plate surface. SOLUTION: A planographic printing original plate with a photosensitive composition layer containing at least a phohothermal conversion material which absorbs light and converts it to heat and an alkali-soluble organic high-molecular substance on the substrate is produced by following steps, (a) imagewise exposure, (b) developing with an alkaline developing solution and (c) washing with water containing a chelate forming material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for making a photosensitive lithographic printing plate, and more particularly to a method for making a lithographic printing plate having a positive photosensitive composition having high sensitivity to the near infrared region. The present invention relates to a method for making a positive photosensitive lithographic printing plate suitable for direct plate making using a semiconductor laser, a YAG laser or the like.

[0002]

2. Description of the Related Art With the advance of computer image processing technology, photosensitive or heat-sensitive direct plate making in which a resist image is directly formed by laser light or a thermal head without outputting digital image information to a silver halide mask film. The system is drawing attention. In particular, the realization of a high-resolution laser-sensitive direct plate making system using a high-output semiconductor laser, a YAG laser, or the like is strongly desired in terms of miniaturization, environmental light during plate making work, and plate material cost. Was.

On the other hand, conventionally, as an image forming method utilizing laser exposure or heat sensitivity, a method of forming a color material image using a sublimation transfer dye and a method of preparing a lithographic printing plate have been known. In recent years, techniques that combine a chemically amplified photoresist with a long-wavelength light-absorbing dye have come to be seen. For example, JP-A-6-43633 discloses a photosensitive material in which a specific squarylium-based dye is combined with a photoacid generator and a binder.
Japanese Patent Application Laid-Open No. 7-29294 discloses a method for preparing a lithographic printing plate by imagewise exposing a photosensitive composition layer containing an infrared absorbing dye, a latent Bronsted acid, a resol resin and a novolak resin by a semiconductor laser or the like. Japanese Patent Application Laid-Open No. 9-43847 discloses a method of using an s-triazine-based compound instead of the latent Bronsted acid.
JP-A-10-3165 discloses a resist material which changes the crystallinity of a photosensitive material by heating by irradiation of infrared rays, and a pattern forming method using the same.
A photosensitive composition in which a specific dissolution inhibitor and an infrared absorbing dye are combined using an acrylic resin or the like as a binder is disclosed.

[0004]

When these photosensitive compositions are used in a lithographic printing plate, most of them are developed by an alkaline developer, but depending on the quality of washing water used in a washing step after development. It has been found that a problem arises in that a white deposit unsuitable for printing is formed on the plate surface. If this adhered substance is formed on the image area, the adhesion of the printing ink to the image area is hindered. As a result, white spots appear on the printed matter, and when formed on the non-image area, Has a problem that the printing ink adheres, and as a result, the ink becomes stained on the printed matter. The present invention has been made in view of the above findings, and has as its object to provide a plate making method for preparing a lithographic printing plate having no unsuitable deposits on a printing plate.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that a photothermal conversion material which absorbs light and converts it into heat, and an alkali-soluble organic polymer material are provided on a support. In the plate making method of a lithographic printing plate having a photosensitive composition layer containing at least, the plate making method is at least (a) an imagewise exposure step, (b) a developing step using an alkaline developer, and (c) a washing step And a method of making a lithographic printing plate wherein the washing water used in the washing step contains a chelating substance, or the calcium concentration in the washing water used in the washing step is 75 p.
It has been found that the above-mentioned object can be achieved by using a lithographic printing plate making method characterized by being at most pm or less, and the present invention has been completed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a lithographic printing plate used in the present invention will be described. The lithographic printing plate used in the invention has at least a layer made of a photosensitive composition containing at least a photothermal conversion substance that absorbs light and converts it into heat and an alkali-soluble organic polymer substance. The photosensitive composition may be positive or negative as long as it contains the above components,
In the case of a negative type, it generally contains a compound capable of generating an acid by laser irradiation and a component capable of crosslinking the alkali-soluble organic polymer substance by the action of the acid. Hereinafter, the positive type photosensitive composition will be mainly described, but the negative type composition also includes the same photothermal conversion substance and alkali-soluble organic polymer substance. The photothermal conversion material is not particularly limited as long as it is a compound capable of converting absorbed light into heat, but a light-absorbing dye having an absorption band in a part or all of a wavelength range of 650 to 1300 nm is particularly effective. These light-absorbing dyes efficiently absorb light in the above-mentioned wavelength region, but hardly absorb light in the ultraviolet region, or do not substantially respond to absorption, and are weakly sensitive to ultraviolet light contained in white lamps. Is a compound having no action of modifying the photosensitive composition.

[0007] These light absorbing dyes include a nitrogen atom,
Representative examples include so-called cyanine-based dyes in which a heterocyclic ring containing an oxygen atom, a sulfur atom, or the like is bonded by polymethine (-CH =) _n , and specifically, for example, quinoline-based ( So-called cyanine in a narrow sense, indole (so-called indocyanine), benzothiazole (so-called thiocyanine), aminobenzene (so-called)
Polymethine-based), pyrylium-based, thiapyrylium-based, squarylium-based, croconium-based, azurenium-based, and the like, and in addition, diiminium-based dyes, phthalocyanine-based dyes, and the like are also typical examples.

In the present invention, among the cyanine-based dyes, quinoline-based dyes include those represented by the following general formula (I)
Those represented by a), (Ib), or (Ic) are preferred.

[0009]

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[In the formulas (Ia), (Ib) and (Ic), R ¹ and R
² each independently has an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, or a group which has a substituent. L ¹ represents a tri-, penta- or heptamethine group which may have a substituent,
The two substituents on the penta or heptamethine group may be connected to each other to form a cycloalkene ring having 5 to 7 carbon atoms, and the quinoline ring may have a substituent,
In that case, two adjacent substituents may be connected to each other to form a fused benzene ring. X ^- is a counter anion. ]

Here, R ¹ in the formulas (Ia), (Ib) and (Ic)
And the substituent for R ² include an alkoxy group, a phenoxy group, a hydroxy group, or a phenyl group, and the substituent for L ¹ includes an alkyl group, an amino group, or a halogen atom, and a quinoline ring. Examples of the substituent in the above include an alkyl group, an alkoxy group, a nitro group, and a halogen atom.

As the indole and benzothiazole dyes, those represented by the following formula (II) are particularly preferred.

[0013]

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[0014] wherein (II), Y ¹ and Y ² each independently represents a dialkyl methylene group or a sulfur atom, R ³
And R ⁴ are each independently an alkyl group optionally having a substituent, an alkenyl group optionally having a substituent, an alkynyl group optionally having a substituent, or a group having a substituent. L ² represents a tri, penta or heptamethine group which may have a substituent, and two substituents on the penta or heptamethine group are linked to each other to form 5 to 7 cycloalkene rings may be formed, and the fused benzene ring may have a substituent. In this case, two adjacent substituents are connected to each other to form a fused benzene ring. You may. X ^- is a counter anion. ]

In the formula (II), examples of the substituent at R ³ and R ⁴ include an alkoxy group, a phenoxy group, a hydroxy group, and a phenyl group, and the substituent at L ² is an alkyl group. , An amino group, or a halogen atom. Examples of the substituent on the benzene ring include an alkyl group, an alkoxy group, a nitro group, and a halogen atom.

Further, as the aminobenzene-based dye, those represented by the following general formula (III) are particularly preferred.

[0017]

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[In the formula (III), R ⁵ , R ⁶ , R ⁷ and R
⁸ each independently represents an alkyl group; R ⁹ and R ¹⁰ each independently represent an aryl group which may have a substituent;
L ³ represents a mono-, tri-, or pentamethine group which may have a substituent; L ² represents a furyl group or a thienyl group; To 7 cycloalkene rings may be formed, and the quinone ring and the benzene ring may have a substituent. X ^- is a counter anion. ]

Here, R ⁹ and R ¹⁰ in the formula (III) are specifically phenyl, 1-naphthyl, 2-naphthyl, 2-furyl, 3-furyl, 2-thienyl. ,
3-thienyl group and the like, and as a substituent thereof, an alkyl group, an alkoxy group, a dialkylamino group,
Hydroxy group or a halogen atom, can be mentioned, L ³
Examples of the substituent in include an alkyl group, an amino group, and a halogen atom.Examples of the substituent in the quinone ring and the benzene ring include an alkyl group, an alkoxy group,
Examples thereof include a nitro group and a halogen atom.

The pyrylium-based and thiapyrylium-based dyes are particularly preferably those represented by the following formulas (IVa), (IVb), or (IVc).

[0021]

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[In the formulas (IVa), (IVa) and (IVc), Z ¹
And Z ² each independently represent an oxygen atom or a sulfur atom; R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ each independently represent a hydrogen atom or an alkyl group, or R ¹¹ and R ¹³ , and R ¹²
And R ¹⁴ may be linked to each other to form a cycloalkene ring having 5 or 6 carbon atoms, and L ⁴ represents a mono-, tri-, or pentamethine group which may have a substituent; The two substituents on the pentamethine group may be linked to each other to form a cycloalkene ring having 5 to 7 carbon atoms, and the pyrylium ring and the thiapyrylium ring may have a substituent. May be linked to each other to form a fused benzene ring.
X ^- is a counter anion. ]

Here, examples of the substituent for L ⁴ in formulas (IVa), (IVa) and (IVc) include an alkyl group, an amino group and a halogen atom, and the substituent on the pyrylium ring and the thiapyrylium ring. Examples of the group include an aryl group such as a phenyl group and a naphthyl group.

Further, as the diiminium-based dye, quinone diiminium represented by the following formula (Va) or (Vb) is particularly preferable.

[0025]

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In the formulas (Va) and (Vb), R^Fifteen, R¹⁶,
R¹⁷, R¹⁸, R¹⁹, R²⁰, R^{twenty one}, And R ^{twenty two}Are independent
Represents a hydrogen atom, an alkyl group, or a phenyl group,
The quinone ring and the benzene ring may have a substituent.
X^-Represents a counter anion. Note that the electronic bond in the formula (Vb)
(...) indicates a resonance state with another electronic bond. ]

Here, examples of the substituent on the quinone ring and the benzene ring in the formulas (Va) and (Vb) include an alkyl group, an alkoxy group, an acyl group, a nitro group, and a halogen atom.

The above-mentioned general formulas (Ia to c), (II) and (III)
 , (IVa-c) and (Va-b)^-When
For example, Cl^-, Br^-, I^-, ClO_Four ^-,
PF₆ ^-And BF_Four ^-, BCl_Four ^-Inorganic boric acid, etc.
Inorganic acid anion, benzenesulfonic acid, p-toluene
Sulfonic acid, naphthalene sulfonic acid, acetic acid and methyl
, Ethyl, propyl, butyl, phenyl, methoxyp
Phenyl, naphthyl, difluorophenyl, pentafluoro
With organic groups such as rophenyl, thienyl, pyrrolyl, etc.
Organic acid anions such as boric acid can be mentioned. this
Among them, the dye having a borate anion as a counter ion is coated.
Because of its excellent solubility in cloth solvents, use a solvent with a low boiling point.
It is preferable because it can be used.

As described above, the quinoline dyes represented by the general formulas (Ia to c), the indole or benzothiazole dyes represented by the general formula (II), and the amino acids represented by the general formula (III) Specific examples of the benzene dye and the pyrylium-based or thiapyrylium-based dyes represented by the general formulas (IVa to c) are shown below.

[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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[0037]

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[0038]

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[0039]

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Also, "special functional dyes" (edited by Ikemori and Hashiya, 1986, published by CMC Corporation), "chemicals of functional pigments" (edited by Higaki, 1981, published by CMC Corporation), " Dye Handbook "(edited by Okawa, Hirashima, Matsuoka, Kitao, published by Kodansha)
Exciton Inc., a catalog published in 1995.
Epo, a laser dye catalog published in 1989
lin Inc. Catalog "E" issued in 1996
and NK-123, NK-124, and NK-220 of the Japan Photosensitive Dye Laboratories.
4 "," NK-2268 "," NK-2545 "," N
K-2677 "," NK-3027 "," NK-350
8 "," NK-3555 "," NKX-113 "," N
Excit, such as “KX-114” and “NKX-1199”
on Inc. "IR-26", "IR-132",
“IR-140”, “DNTPC-P”, “DNDTP
Epolin, such as "CP", "Q-Switch5"
Inc. "Epolite III-57", "Ep
olite III-117 "," Epolite I
II-130 "," Epolite III-17 "
8 "," Epolite III-184 "," Epo
lite III-189 "," Epolite II "
I-192 "," Epolite IV-62A ",
"Epolite V-63", "Epolite V
-73 "," Epolite V-99 "," Epol
item V-149 "and the like are preferable.

The content ratio of the photothermal conversion substance in the photosensitive composition included in the lithographic printing plate used in the present invention is 1
It is preferably from 70 to 70% by weight, particularly preferably from 2 to 60% by weight, further preferably from 3 to 50% by weight.

The photosensitive composition included in the lithographic printing plate used in the present invention contains an alkali-soluble organic polymer as an essential component. Examples of the alkali-soluble organic polymer include, for example, a novolak resin, a resol resin, a polyvinylphenol resin, and a copolymer of an acrylic acid derivative having a phenolic hydroxyl group.In the novolak resin, the resol resin, or the polyvinyl Phenolic resins are preferred, and novolak resins are particularly preferred.

The novolak resin is, for example, phenol,
o-cresol, m-cresol, p-cresol,
2,5-xylenol, 3,5-xylenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, propylphenol, n-butylphenol, tert-butylphenol, 1-naphthol, 2
-At least one phenol such as naphthol, 4,4'-biphenyldiol, bisphenol-A, pyrocatechol, resorcinol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, phloroglucinol and the like under an acidic catalyst; For example, formaldehyde,
Aldehydes such as acetaldehyde, propionaldehyde, benzaldehyde and furfural (paraformaldehyde may be used in place of formaldehyde and paraaldehyde in place of acetaldehyde), or ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone A resin polycondensed with at least one of the following, wherein, in the present invention,
Phenol as a phenol, o-cresol, m
-Cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, polycondensates of resorcinol with formaldehyde, acetaldehyde, propionaldehyde as aldehydes or ketones are preferable, and especially m-cresol: p -Cresol: 2,
The mixing ratio of 5-xylenol: 3,5-xylenol: resorcinol is 40 to 100: 0 to 50: 0 in molar ratio.
Mixed phenols having a molar ratio of 1 to 100: 0 to 70: 0 to 60: 0 to 20: 0 to 20: 0 to 20 or mixed phenols of phenol: m-cresol: p-cresol; Polycondensates with formaldehyde are preferred.

The novolak resin preferably has a weight average molecular weight (M _w ) in terms of polystyrene determined by gel permeation chromatography, preferably from 1,000 to 1.
5,000, particularly preferably 1,500 to 10,000
Is used.

The resol resin is a novolak resin.
Instead of using an alkali catalyst instead of an acid catalyst in polycondensation
The outside is a resin that has been polycondensed in the same manner.
In the same manner as in the novolak resin,
And their mixed compositions, and aldehydes or kerosene
Tons are preferred and also have similar weight average molecular weights.
(M _wIs preferred.

Polyvinyl phenol resins include, for example, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene,
Trihydroxystyrene, tetrahydroxystyrene,
Hydroxystyrenes such as pentahydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl) propylene, and 2- (p-hydroxyphenyl) propylene (these include chlorine and bromine in the benzene ring; , A halogen atom such as iodine or fluorine, or an alkyl group having 1 to 4 carbon atoms as a substituent.) In the presence of a radical polymerization initiator or a cationic polymerization initiator. In the present invention, a polymer of hydroxystyrenes which may have an alkyl group having 1 to 4 carbon atoms as a substituent on a benzene ring is preferable. A polymer of a hydroxystyrene having a substituted benzene ring is preferred.

The polyvinyl phenol resin further comprises:
A partially hydrogenated product may be used, or a partially tert-butoxycarbonyl group, a pyranyl group, a furyl group, or the like, in which some hydroxyl groups are protected. Also, the weight average molecular weight (M
_w ) is preferably from 1,000 to 100,000, particularly preferably from 1,500 to 50,000.

If the molecular weight of the novolak resin, resol resin and polyvinylphenol resin is smaller than the above range, a sufficient coating film as a resist cannot be obtained. If the molecular weight is larger than the above range, the solubility in an alkali developing solution is low. In such a case, there is a tendency that the omission of the exposed portion becomes insufficient and it becomes difficult to obtain a resist pattern.

The content of the alkali-soluble organic high molecular substance in the photosensitive composition of the lithographic printing plate used in the present invention is preferably 30 to 99% by weight,
Particularly preferred is 40 to 98% by weight, and 50 to 97% by weight.
More preferably, it is% by weight.

The photosensitive composition included in the lithographic printing plate used in the present invention contains light in the near infrared region for the purpose of increasing the difference in solubility between exposed and unexposed areas in an alkali developing solution. May be contained.

Examples of the dissolution inhibitor include sulfonic acid esters, phosphoric acid esters, aromatic carboxylic acid esters, aromatic disulfones, and carboxylic anhydrides described in detail in JP-A-10-268512. , Aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as described in Japanese Patent Application No. 9-2918.
A lactone skeleton described in detail in No. 80;
Dyes having an N, N-diarylamide skeleton and a diarylmethylimino skeleton, and dyes having a lactone skeleton, a thiolactone skeleton, and a sulfolactone skeleton, which are also described in detail in Japanese Patent Application No. 9-301915 are exemplified. it can.

Further, as dissolution inhibitors, for example, polyethylene glycols, polyethylene glycol polypropylene glycol block copolymers, polyethylene glycol alkyl ethers, polyethylene glycol polypropylene glycol alkyl ethers, polyethylene glycol alkyl phenyl ethers, polyethylene glycol fatty acid esters , Polyethylene glycol alkyl amines, polyethylene glycol alkyl amino ethers, glycerin fatty acid esters and their polyethylene oxide adducts, sorbitan fatty acid esters and their polyethylene oxide adducts, sorbite fatty acid esters and their polyethylene oxide adducts, pentaerythritol Fatty acid esters and their polyethylene Oxide adducts, nonionic surfactants such as polyglycerol fatty acid esters.

When the lithographic printing plate used in the present invention contains the dissolution inhibitor in the photosensitive composition, the content is preferably 50% by weight or less, and 0.01 to 3% by weight.
0% by weight is particularly preferred, and 0.1 to 20% by weight.
Is more preferable.

The photosensitive composition included in the lithographic printing plate used in the present invention is preferably an organic acid having _a pKa of 2 or more and an organic acid thereof for the purpose of improving developability such as imparting under developability. An acid anhydride may be contained.

Examples of the organic acid and its anhydride include, for example, JP-A-60-88942 and JP-A-63-2760.
48, JP-A-2-96754 and the like, and specifically, glyceric acid, methylmalonic acid, dimethylmalonic acid, propylmalonic acid, succinic acid, malic acid, mesotartaric acid, Glutaric acid, β-methylglutaric acid, β, β-dimethylglutaric acid, β-ethylglutaric acid, β, β-diethylglutaric acid, β-propylglutaric acid, β, β-methylpropylglutaric acid, pimelic acid, suberin Acid, aliphatic saturated carboxylic acid such as sebacic acid, aliphatic unsaturated carboxylic acid such as maleic acid, fumaric acid, glutaconic acid, 1,1-cyclobutanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,1-cyclohexane Pentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,1-cyclohexanedicarboxylic acid, 1,
Carbocyclic saturated carboxylic acids such as 2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexenedicarboxylic acid, 2,3-dihydroxybenzoic acid, 3,
4-dimethylbenzoic acid, 3,4-dimethoxybenzoic acid,
3,5-dimethoxybenzoic acid, p-toluic acid, 2-hydroxy-p-toluic acid, 2-hydroxy-m-toluic acid, 2-hydroxy-o-toluic acid, mandelic acid, gallic acid, phthalic acid, isophthalic acid Acids, carbocyclic unsaturated carboxylic acids such as terephthalic acid, and Meldrum's acid,
Examples thereof include anhydrides such as ascorbic acid, succinic anhydride, glutaric anhydride, maleic anhydride, cyclohexenedicarboxylic anhydride, cyclohexanedicarboxylic anhydride, and phthalic anhydride.

When the lithographic printing plate used in the present invention contains the organic acid and the anhydride of the organic acid in the photosensitive composition, the content is preferably 30% by weight or less. It is particularly preferred that the content is from 0.01 to 20% by weight,
More preferably, it is 0.1 to 10% by weight.

In the photosensitive composition included in the lithographic printing plate used in the present invention, in addition to the above components, for example, dyes, pigments, coatability improvers, adhesion improvers, sensitivity improvers, sensitizers And the like, may be further contained in an amount of 20% by weight or less, preferably 10% by weight or less.

The photosensitive composition included in the lithographic printing plate used in the present invention contains the photothermal conversion substance and the alkali-soluble organic polymer substance as essential components, and as described above, a dissolution inhibitor, a developability improver and the like. Although it is permissible to contain an additive of the formula (1) and to contain an o-quinonediazide group-containing compound, it is not essential to include the o-quinonediazide group-containing compound, and it has an advantage that it can be handled under a white light. Therefore, it is preferable not to contain an o-quinonediazide group-containing compound. That is, the composition is distinguished from an alkali-soluble resin conventionally known as a positive photosensitive composition and a composition essentially containing an o-quinonediazide group-containing compound as a photosensitizing component. That is, a conventional positive photosensitive composition containing an o-quinonediazide group-containing compound is an alkali-soluble resin due to photolysis of the diazo part of the o-quinonediazide group-containing compound by irradiation with ultraviolet light to form a carboxylic acid. It is believed that the alkali solubility of the compound increases and an image is formed by dissolving the exposed part in an alkali developing solution, whereas the positive photosensitive composition of the present invention has the chemical change due to the exposure. Without this, the light energy absorbed by the photothermal conversion material is converted into heat, and the alkali-soluble organic polymer material in the heat-received portion causes a change other than a chemical change such as a conformational change, and the alkali in the portion is changed. It is considered that an image is formed by the alkali developer by increasing the solubility. The details of this are described in, for example, Japanese Patent Application Laid-Open No. 10-268512.

The photosensitive composition included in the lithographic printing plate used in the present invention is usually applied to the surface of a support as a solution in which the above components are dissolved in an appropriate solvent, and then heated and dried to obtain a support. Formed as a photosensitive composition layer on the surface.

Here, the solvent is not particularly limited as long as it has a sufficient solubility for the components used and gives good coating properties. For example, methylcellosolve,
Cellosolve solvents such as ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate , Propylene glycol solvents such as dipropylene glycol dimethyl ether, butyl acetate, amyl acetate, ethyl butyrate, butyl butyrate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, methyl lactate, ethyl lactate, Ester solvents such as methyl 3-methoxypropionate, heptanol Hexanol, diacetone alcohol, alcohol solvents such as furfuryl alcohol, cyclohexanone, ketone solvents such as methyl amyl ketone,
Highly polar solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like, or a mixed solvent thereof, and further a mixture thereof with an aromatic hydrocarbon may be used. The usage ratio of the solvent is usually in the range of about 1 to 20 times by weight based on the total amount of the photosensitive composition.

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. The coating amount varies depending on the application, but is usually 0.3 to 7 as a dry film thickness.
μm, preferably 0.5 to 5 μm, particularly preferably 1 to
The range is 3 μm. The drying temperature at that time is, for example, about 60 to 170 ° C., preferably 70 to 1 ° C.
The drying time is, for example, about 5 seconds to 10 minutes, preferably about 10 seconds to 5 minutes.

It is to be noted that improvement in contrast at the time of forming an image,
And, for the purpose of, for example, improving temporal stability of image forming properties,
For example, about 40 to 120 ° C, preferably 40 to 70 ° C
At a temperature of about 5 minutes to 100 hours, preferably 30 minutes.
It is preferable to perform a post-heating treatment for about minutes to 75 hours.

The support is made of aluminum.
Metal, zinc, copper, steel, etc., aluminum, zinc,
Gold plated or deposited with copper, iron, chromium, nickel, etc.
Metal plate, paper, resin coated paper, metal foil such as aluminum
Paper, plastic film, hydrophilized
Examples include a plastic film and a glass plate.
Among them, preferred is an aluminum plate, hydrochloric acid or
By electrolytic etching or brush polishing in nitric acid solution
Graining, anodizing in sulfuric acid solution, and necessary
Aluminum that has been subjected to surface treatment such as sealing according to
Plates are more preferred. In addition, as the roughness of the support surface,
Average roughness R specified in JIS B0601 _aIn
Usually 0.3 to 1.0 μm, preferably 0.4 to 0.8 μm
m.

The plate making method of the present invention comprises at least (a) an imagewise exposure step, (b) a development step using an alkaline developer,
(c) Includes a washing step. The light source used in the "imagewise exposure step" of the present invention mainly includes a laser light source such as a HeNe laser, an argon ion laser, a YAG laser, a HeCd laser, a semiconductor laser, and a ruby laser. When an image is formed by generated heat, a light source that generates a laser beam of 650 to 1300 nm is preferable, and examples thereof include a solid laser such as a ruby laser, a YAG laser, a semiconductor laser, and an LED. A long-life semiconductor laser or YAG laser is preferable.

The laser light source usually scans the surface of the photosensitive composition layer as a high-intensity light beam (beam) condensed by a lens, and the sensitivity of the photosensitive composition layer according to the present invention responds to the scanning. The characteristic (mJ / cm ² ) may depend on the light intensity (mJ / s · cm ² ) of the received laser beam. Here, the light intensity of the laser beam is obtained by dividing the amount of energy per unit time (mJ / s) of the laser beam measured by the optical power meter by the irradiation area (cm ² ) of the laser beam on the surface of the photosensitive composition layer. Can be obtained by The irradiation area of the laser beam is usually defined as an area of a portion exceeding 1 / e ² intensity of the laser peak intensity, but it can be simply measured by exposing a photosensitive composition exhibiting a reciprocity law. . In the present invention, the light intensity of the light source is 2.0 × 10 ⁶
mJ / s · cm ² or more, preferably 1.0 ×
It is particularly preferable to be 10 ⁷ mJ / s · cm ² or more. When the light intensity is in the above range, the sensitivity characteristic of the photosensitive composition layer in the present invention can be improved, and the scanning exposure time can be shortened, which is a great practical advantage. In the present invention, in the case of performing imagewise exposure using a laser beam, each exposure method of outer drum scanning exposure, inner drum scanning exposure, and plane scanning exposure can be used. Among these exposure methods, the outer drum scanning exposure and the inner drum scanning exposure are preferable because a high resolution and high definition image can be exposed.

The developing solution used in the "development step using an alkaline developing solution" of the present invention may be an alkaline developing solution which can be removed by development at a laser-exposed portion. , And a silicate of an alkali metal. The pH of the developer is 1
It is preferably 2.0 or more, and more preferably 12.
5 or more, more preferably 13.0 or more. When the alkali metal hydroxide and the alkali metal silicate are not contained, hydrophilization becomes insufficient, and when the pH is less than the above range, the releasability of the exposed portion may be poor. Further, the pH is preferably 14.0 or less. If the pH is higher than 14.0, the influence of neutralization deterioration by carbon dioxide in the air is large, and the developer may be unstable.

Here, as the alkali agent, hydroxides of alkali metals include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. As silicates of alkali metals, sodium silicate and potassium silicate And lithium silicate.

The developer used in the "development step using an alkaline developer" of the present invention preferably contains silicones. When silicones are contained, the film loss at the time of development of the unexposed portion is reduced, and as a result, the range of development conditions can be widened. As silicones, a siloxane bond is used as a skeleton, and specifically, for example, dimethylpolysiloxane or a silicone oil having a main chain in which a part of a methyl group is substituted with hydrogen or a phenyl group, a silicone resin, or the like. , A silicone oil used as a solution type, an emulsion type, and a compound type are preferable, and among them, those used as an antifoaming agent are preferable. Further, a copolymer of dimethylpolysiloxane and a polyalkylene oxide is preferable. Those having self-emulsifying hydrophilicity such as described above are particularly preferred.

The developing solution used in the "development step using an alkaline developing solution" of the present invention contains a silicate of an alkali metal in an amount of 0.5 to 5% by weight, particularly preferably 1.0 to 5% by weight, as silicon dioxide. ~ 4.0% by weight. Further, the content of silicones is 1 to 10000 ppm, particularly 5 to 1000 ppm.
It is preferably ppm.

Further, the developing solution used in the "development step using an alkaline developing solution" of the present invention is a cationic, anionic, nonionic or amphoteric surfactant because it can stably broaden the range of developing conditions. It is preferable that the composition contains an agent, and the content is 10 to 10000 ppm, particularly preferably 100 to 5000 ppm.

Here, as the cationic surfactant,
Specifically, for example, quaternary ammonium salts such as lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, perfluorotrimethylammonium chloride, laurylpyridinium chloride, Imidazoline derivatives such as 2-octadecyl-hydroxyethyl-2-imidazoline, N, N-diethyl-stearamide-
Examples thereof include amine salts such as methylamine hydrochloride and polyoxyethylene stearylamine.

Examples of the anionic surfactant include higher fatty acid salts such as sodium laurate, sodium stearate and sodium oleate; alkyl sulfate salts such as sodium lauryl sulfate and sodium stearyl sulfate; sodium octyl alcohol sulfate; Higher alcohol sulfates such as sodium alcohol sulfate and ammonium lauryl alcohol sulfate; aliphatic alcohol sulfates such as sodium acetyl alcohol sulfate; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; sodium isopropylnaphthalene sulfonate; Alkyl naphthalene sulfonates, alkyl diphenyls such as sodium alkyl diphenyl ether disulfonate Alkyl phosphates such as nyl ether disulfonates, sodium lauryl phosphate and sodium stearyl phosphate, polyethylene oxide adducts of sodium lauryl ether sulfate, polyethylene oxide adducts of ammonium lauryl ether sulfate, and polyethylene oxide adducts of lauryl ether triethanolamine sulfate Alkyl ethers such as polyethylene oxide adducts of alkyl ether sulfates, such as polyethylene oxide adducts of sodium nonylphenyl ether sulfate, and polyethylene oxide adducts of alkyl phenyl ether sulfate, and polyethylene oxide adducts of sodium lauryl ether phosphate. Polyethylene oxide adducts of phosphate, polyethylene of sodium nonylphenyl ether phosphate Can be exemplified emissions oxide adducts of polyethylene oxide adducts of alkyl phenyl ether phosphate salts such like.

Examples of the nonionic surfactant include polyethylene glycols such as polyethylene glycol and polyethylene glycol polypropylene glycol block copolymer, and polyethylene such as polyethylene glycol cetyl ether, polyethylene glycol stearyl ether, polyethylene glycol oleyl ether and polyethylene glycol behenyl ether. Glycol alkyl ethers, polyethylene glycol polypropylene glycol cetyl ether, polyethylene glycol polypropylene glycol alkyl ethers such as polyethylene glycol polypropylene glycol decyl tetradecyl ether, polyethylene glycol octyl phenyl ether, polyethylene glycol nonyl phenyl ether Polyethylene glycol alkyl phenyl ethers, ethylene glycol monostearate, ethylene glycol distearate, diethylene glycol stearate, polyethylene glycol distearate, polyethylene glycol monolaurate,
Glycerin fatty acids such as polyethylene glycol fatty acid esters such as polyethylene glycol monostearate and polyethylene glycol monooleate, glyceryl monomyristate, glyceryl monostearate, glyceryl monoisostearate, glyceryl distearate, glyceryl monooleate and glyceryl dioleate. Esters, and their polyethylene oxide adducts, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, and the like, and their polyethylene oxide adducts, Sorbit monolaurate, Sorbit tetrastearate, Sorbit hexastearate, Sole tetraoleate Sorbit fatty acid esters such as Tsu bets, and polyethylene oxide adducts, can be mentioned castor oil polyethylene oxide adducts such as.

The amphoteric surfactants include N-lauryl-N, N-dimethyl-N-carboxymethylammonium, N-stearyl-N, N-dimethyl-N-carboxymethylammonium, N-lauryl-N, Betaine-type compounds such as N-dihydroxyethyl-N-carboxymethylammonium, N-lauryl-N, N, N-tris (carboxymethyl) ammonium, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium Imidazolium salts, imidazoline-
N-sodium ethyl sulfonate, imidazoline-N
Imidazolines such as sodium ethyl sulfate;

Among the above surfactants, the quaternary ammonium salts as cationic surfactants, the various polyethylene glycol derivatives as nonionic surfactants, the various polyethylene oxide adducts, etc. Polyethylene oxide derivatives of the above, and betaine type compounds as an amphoteric surfactant are preferred.

The developing solution used in the "development step using an alkaline developing solution" of the present invention contains, in addition to the alkali agent, the silicones and the surfactant, a pH adjusting agent, if necessary. An additive such as an agent or an antifoaming agent can be contained. These additives can be contained in the alkali developer at a concentration of preferably 0.001 to 5% by weight, particularly preferably 0.005 to 3% by weight.

The developing step is preferably performed by immersion development, spray development, brush development, ultrasonic development, or the like.
It is carried out at a temperature between -50 ° C, particularly preferably between 20-40 ° C.

The main purpose of the "water-washing step" of the present invention is to wash off the developer from the lithographic printing plate. The washing water in the present invention is mainly composed of water, and may contain impurities such as calcium and any additives.In the present invention, such washing water contains a chelating substance, or It is essential that the concentration of calcium in the washing water is 75 ppm or less.

Although any substance can be used as the chelating substance, amines having an acidic group or derivatives thereof are preferable. Here, the amine having an acidic group refers to an aliphatic, alicyclic, or aromatic hydrocarbon amine, and is not limited to a monoamine, and may be a polyamine such as a diamine or a triamine. , A secondary amine or a tertiary amine, but may have at least one, preferably at least one, carboxyl group such as a carboxyl group, a sulfone group, a phosphoric acid group, or a phenol group. A compound having the above, wherein the acidic group is an ammonium salt, sodium,
It may be a derivative such as a salt such as a metal salt such as potassium or an ester such as an alkyl ester having 1 to 4 carbon atoms, and further has a substituent such as a hydroxyl group, a carbonyl group, an aryl group or a halogen atom. May be. Further, the molecular weight is preferably 2000 or less, more preferably 1000 or less. As the chelating substance, a water-soluble substance is preferable.

In the present invention, specific examples of the amine having an acidic group or derivatives thereof include ethylenediamine monoacetic acid, ethylenediamine diacetic acid, ethylenediamine triacetic acid, ethylenediaminetetraacetic acid, aminobutyric acid, aspartic acid, glutamic acid, lauryl- β
-Iminodipropionic acid, cysteic acid, N-phenylglycine, phenylalanine, N-phenylalanine,
Derivatives such as tyrosine, ethylanilinodiacetic acid and the like, and their partial salts of metals such as sodium and potassium, partial salts of ammonium, partial methyl esters, partial ethyl esters, and the like can be given. Among them, ethylenediaminetetraacetic acid or a metal salt thereof, monoaminodicarboxylic acid such as aspartic acid or glutamic acid or a metal salt thereof are preferable, and a metal salt of ethylenediaminetetraacetic acid is particularly preferable. Here, "part" refers to a state in which some or all of the carboxyl groups present in each compound and a derivative such as a salt or an ester are formed, and the number of compounds is an average of each compound. Say value,
It is not necessarily limited to natural numbers.

In the first aspect of the present invention, the weight concentration of the chelating substance in the washing water is not less than 0.001% and not more than 15%.
Or less, more preferably 0.005
% To 10%, more preferably 0.01%
Not less than 5%. If the added amount of the chelate forming substance is too small, the effect is not sufficiently exhibited, and if the added amount is too large, the chelate forming substance conversely contaminates the surface of the lithographic printing plate and causes a problem on a printing press. Sometimes.
In particular, when the washing water contains calcium, the effect of containing the chelate-forming substance is remarkable. In that case, the standard of the amount of the chelate-forming substance to be added differs depending on the type of the chelate-forming substance. It is particularly preferable to add it so that the molar equivalent to form a chelate compound with calcium in water is not less than the molar equivalent.

In the second aspect of the present invention, if the concentration of calcium in the washing water is 75 ppm or less, it is not necessary to contain a chelating substance. The concentration of calcium is preferably 0.001 ppm or more and 75 ppm or less, more preferably 0.005 ppm or more and 50 ppm or less, and still more preferably 0.01 ppm or more and 25 ppm.
Or less, particularly preferably 0.05 ppm or more and 10 ppm
It is as follows. In the present invention, the concentration of calcium in the washing water is defined as the weight concentration converted into CaCO ₃ . Further, the calcium concentration in the present invention is not limited in its form, and may be present as free calcium or calcium constituting a chelate. The concentration can be easily measured by, for example, an atomic absorption method. A purification method using an ion exchange resin or a reverse osmosis membrane method is preferable because washing water having a low calcium concentration can be easily prepared.

In the present invention, the washing water contains a chelating substance and has a calcium concentration of 75 p.
pm or less.

The washing water may contain an antifoaming agent such as a silicone compound for the purpose of suppressing foaming, and sodium hydroxide or potassium hydroxide for the purpose of preventing the photosensitive composition from re-adhering to the plate surface. And the like. The temperature of the washing water is usually 10 to 40 ° C, preferably 15 to 40 ° C.
The washing time is usually about 2 to 120 seconds, preferably 5 to 60 seconds, more preferably 10 to 45 seconds.

The method of making a lithographic printing plate according to the present invention must include at least three steps: (a) an imagewise exposure step, (b) a development step using an alkaline developer, and (c) a washing step. Yes, these three steps are preferably performed in this order. After the washing step (c), a step of applying a plate surface protective liquid containing gum arabic, dextrins, carboxymethyl celluloses, phosphoric acid or the like to the plate surface and a drying step are preferably provided. Before the developing step, a washing step using ordinary washing water may be provided.

[0086]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

Examples 1 to 3 and Comparative Example 1 An aluminum plate (0.24 mm thick) was degreased in a 3% by weight sodium hydroxide bath at 60 ° C. for 1 minute. 25 ° C, 80 in hydrochloric acid bath
After performing an electrolytic etching treatment at a current density of A / dm ² for 10 seconds, washing with water, a desmut treatment at 50 ° C. for 3 seconds in a sodium hydroxide bath having a concentration of 10 g / liter, and washing with water,
Anodizing was performed in a 30% by weight sulfuric acid bath at 30 ° C. and a current density of 10 A / dm ² for 15 seconds. Further, at 90 ° C., p
The resultant was subjected to hot water sealing treatment with H9, washed with water, and dried to prepare an aluminum plate for a lithographic printing plate support.

On the surface of the obtained aluminum plate support, 4 parts by weight of the indole dye (“CY-10”, manufactured by Nippon Kayaku Co., Ltd.) shown in the above specific example (II-8) was used as a photothermal conversion material.
Phenol / m as an alkali-soluble organic polymer substance
Novolak resin ( _Mw 9400, manufactured by Sumitomo Durez Co., Ltd.) obtained by polycondensing a mixed phenol of -cresol / p-cresol = 50/30/20 (molar ratio) with formaldehyde.
"SK-188") 100 parts by weight, as a dissolution inhibitor
Polyethylene glycol (manufactured by Toho Chemical Industries, "PEG
# 2000 ") 4 parts by weight and as a developing property improver
A coating solution prepared by dissolving 5 parts by weight of 1,2-cyclohexanedicarboxylic acid in 1000 parts by weight of methyl cellosolve is applied using a wire bar and dried to obtain a photosensitive film having a dry film thickness of 2.5 g / m ² . A lithographic printing plate having a composition layer was prepared.

2830 g of potassium silicate and 712 g of potassium hydroxide were dissolved in 46458 g of water to make the content as silicon dioxide 1.5% by weight, and a betaine-type compound amphoteric surfactant (Daiichi Kogyo Seiyaku Co., Ltd.) "Amogen K") at 800 ppm, Dow Corning Asia
By adding 100 ppm of "S Antiform 80", an alkaline developer having a pH of 13.3 was prepared.

As the washing water, calcium concentrations shown in Table 1 and ethylenediaminetetraacetic acid disodium salt were used.
Rinse water with (EDTA2Na) concentration was used. The calcium concentration was determined by an atomic absorption method. Example 1 and Comparative Example 1 used ordinary tap water.
EDTA2Na was added. In Examples 2 and 3, deionized water passed through an ion exchange resin was used. In Example 3, the amount of EDTA2Na shown in Table 1 was added.

[0091] These alkaline developer and washing water were combined with a Diamond Plate manufactured by Western Lithotech Co., USA.
The developer was charged into a developing tank and a washing tank of a Processor 92 automatic developing machine, and the temperature of the developing solution was set to 34 ° C. and the temperature of the washing water was set to 26 ° C. Thereafter, the lithographic printing plate prepared by the above-described method was applied to a laser exposure machine (Creo, “Tre
ndsetter ”) at 200 mj / cm ² and inserted into the automatic processor described above. In an automatic processor,
First, development processing was performed for 60 seconds with the developing solution by a spray developing method in a developing tank, followed by rinsing with the rinsing water for 25 seconds in a rinsing tank, followed by hot-air drying. The surface of the lithographic printing plate thus prepared was visually observed to check for the presence of white deposits formed on the surface, and a printing test was performed using a sheet-fed printing machine manufactured by Mitsubishi Heavy Industries, Ltd. Table 1 shows the results.

[0092]

[Table 1] Rinse water Rinse water Calcium concentration EDTA2Na weight concentration Presence or absence of white matter Print result Example 1 140 ppm 0.10% ○ No abnormality Example 2 0.1 ppm 0% ○ No abnormality Example 3 0.1 ppm 10% ○ No abnormality Comparative Example 1 140 ppm 0% XX Non-image area stain, image area white spots

In Table 1 “Presence or absence of white deposits”, ○ indicates no deposits, Δ indicates slight deposits, X indicates that deposits are clearly recognized, XX Means that a large amount of deposit is observed.

Comparative Example 2 A test was conducted in exactly the same manner as in Comparative Example 1 except that EDTA2Na was added to the developer so as to have a concentration of 0.04% by weight. As a result, the presence or absence of white matter and the printing result were equivalent to those of Comparative Example 1 and were inferior.

As is clear from the above, according to the method of making a lithographic printing plate of the present invention, there is no white matter unsuitable for printing on the plate surface, and no non-image area stains and image area white spots are present. Good printed matter is obtained.

[0096]

According to the method of making a lithographic printing plate according to the present invention, a good printed matter free of white matter unsuitable for printing on the plate surface and free of non-image area stains and image area white voids can be obtained. Can be

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/32 G03F 7/32 501 501 F-term (Reference) 2H025 AA01 AB03 AC08 AD03 CB17 CB29 CB52 CC20 FA03 FA17 2H084 AA14 AA30 BB02 CC05 2H096 AA07 BA16 BA20 EA02 EA04 GA08 GA09 GA17 GA18

Claims (9)

[Claims] 1. A method for making a lithographic printing plate comprising a support, comprising: a photothermal conversion substance that absorbs light and converts it into heat; and a photosensitive composition layer containing at least an alkali-soluble organic polymer substance. The plate making method is at least (a)
Lithographic printing, comprising: an imagewise exposure step, (b) a development step using an alkaline developer, and (c) a rinsing step, and wherein the rinsing water used in the rinsing step contains a chelate-forming substance. Plate making method. 2. The method according to claim 1, wherein the chelating substance is an amine having an acidic group or a derivative thereof. 3. The method for making a lithographic printing plate according to claim 1, wherein the chelating substance is ethylenediaminetetraacetic acid or a metal salt thereof. 4. The method for making a lithographic printing plate according to claim 1, wherein the concentration of the chelating substance in the washing water is 0.001 to 15% by weight. 5. A method for making a lithographic printing plate comprising a support having thereon a photothermal conversion material that absorbs light and converts it into heat, and a photosensitive composition layer containing at least an alkali-soluble organic polymer material. The plate making method is at least (a)
Lithographic printing, comprising: an imagewise exposure step, (b) a development step using an alkaline developer, and (c) a washing step, and wherein the concentration of calcium in the washing water used in the washing step is 75 ppm or less. Plate making method. 6. The lithographic printing plate making method according to claim 5, wherein the rinsing water is rinsing water purified by a reverse osmosis membrane method or an ion exchange method. 7. An imagewise exposure step comprising 650 to 1300 n
The method according to any one of claims 1 to 6, wherein a laser beam emitted between m and m is used. 8. A lithographic printing plate according to claim 1, wherein the alkaline developer contains at least an alkali metal hydroxide and an alkali metal silicate. Method. 9. The lithographic printing plate according to claim 1, wherein the lithographic printing plate is of a positive type, and the alkali-soluble organic polymer contains a novolak resin. Plate making method.