JPH11119428A - Photosensitive composition and photosensitive planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a planographic printing plate having high sensitivity in a near IR region and capable of reproducing fine dots by incorporating a resin such as a novolak resin, a crosslinking agent of the resin, a near IR absorber, an acid generating agent and a dissolution inhibitor capable of reducing the dissolution rate of these components to an alkaline developer. SOLUTION: The photosensitive compsn. contains a novolak resin or polyvinyl phenol resin, a crosslinking agent of the resin, a near IR absorber, an acid generating agent and a dissolution inhibitor capable of reducing the dissolution rate of these components to an alkaline developer. The crosslinking agent is preferably a melamine deriv. A cyanine dye represented by the formula is preferably contained as the near IR absorber. In the formula, R<1> -R<8> are each H, halogen, nitro or the like, R<9> and R<10> are each alkyl, alkenyl or the like, Y<1> and Y<2> are each dialkylmethylene or S, L<1> is pentamethine or heptamethine and Z<1-> is a counter anion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative photosensitive composition having a high sensitivity to the near infrared region, and a negative photosensitive lithographic printing plate having the photosensitive composition layer formed on the surface of a support. In particular, the present invention relates to a photosensitive composition and a photosensitive lithographic printing plate suitable for direct plate making by a semiconductor laser.

[0002]

2. Description of the Related Art With the advance of computer image processing technology, a photosensitive or heat-sensitive direct plate making in which a resist image is directly formed by a laser beam 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 has been strongly desired because the semiconductor laser has a long life and is small in size.

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 producing a lithographic printing plate have been known. In, specifically,
For example, a method of preparing a lithographic printing plate utilizing a crosslinking reaction of a diazo compound (for example, JP-A-50-15603, JP-A-52-151024, JP-B-60-12939)
No., Japanese Patent Publication No. 61-21831, Japanese Patent Publication No. 2-51732.
No. JP-B-3-34051, U.S. Pat.
See, for example, the specification of No. 4737. ), And a method of preparing a lithographic printing plate utilizing the decomposition reaction of nitrocellulose (see, for example, JP-A-50-102401 and JP-A-50-102403).

[0004] In recent years, a technique of combining a long-wavelength light-absorbing dye with a chemically amplified photoresist has been scattered. For example, JP-A-6-43633 discloses a photosensitive material in which a specific squarylium dye is combined with a photoacid generator and a binder. As a technique similar thereto, JP-A-7-20629 discloses a photosensitive material. 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 resole resin and a novolak resin by a semiconductor laser, etc. No. 271029 discloses a method using an s-triazine compound instead of the latent Bronsted acid. However, these conventional techniques have disadvantages in practical use, such as poor spot reproducibility due to inferior development contrast between exposed and unexposed areas and poor sensitivity.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has as its object to provide a photosensitive lithographic printing plate capable of reproducing small dots with high sensitivity in the near infrared region. And a photosensitive lithographic printing plate.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that the above objects can be achieved by adding a dissolution inhibitor, and have completed the present invention. That is, the present invention provides a photosensitive composition containing the following components (A), (B), (C), (D), and (E), and the photosensitive composition on a support surface. And a photosensitive lithographic printing plate having a layer formed of (A) at least one resin selected from the group consisting of a novolak resin and a polyvinylphenol resin; (B) a resin cross-linking agent for the component (A); (C) a near-infrared absorber; (D) an acid generator; ) To (D), a dissolution inhibitor capable of reducing the dissolution rate in an alkaline developer

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The novolak resin as the component (A) in the present invention comprises phenol, o-cresol, m
-Cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, o-ethylphenol, m
At least one of phenols such as -ethylphenol, p-ethylphenol, propylphenol, n-butylphenol, tert-butylphenol, 1-naphthol, 2-naphthol, resorcinol, 4,4'-biphenyldiol, bisphenol-A, pyrogallol, etc. The species is aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and furfural under an acidic catalyst (paraformaldehyde may be used instead of formaldehyde, and paraaldehyde may be used instead of acetaldehyde), or acetone. , Methyl ethyl ketone, methyl isobutyl ketone and the like, a polycondensed resin with at least one of the above, wherein phenol as a phenol, o-cresol, m-crezo , P-cresol, 2,5-
Xylenol, 3,5-xylenol, resorcinol,
Polycondensates with formaldehyde, acetaldehyde, and propionaldehyde as aldehydes or ketones are preferable, and particularly, the mixing ratio of m-cresol: p-cresol: 2,5-xylenol: 3,5-xylenol: resorcinol is a molar ratio. 70 ~ 100: 0 ~ 3
A mixed phenol of 0: 0 to 20: 0 to 20: 0 to 20 or a mixed ratio of phenol: m-cresol: p-cresol in a molar ratio of 10 to 100: 0 to 60: 0.
Preferred are polycondensates of formaldehyde with mixed phenols of ~ 40.

[0008] The novolak resin has a weight average molecular weight in terms of polystyrene by gel permeation chromatography measurement (M _W) is preferably 1,000 to
5,000, particularly preferably 1,500 to 10,000
Is used.

In the present invention, the polyvinyl phenol resin as the component (A) includes o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene,
Hydroxystyrenes such as (m-hydroxyphenyl) propylene and 2- (p-hydroxyphenyl) propylene (these include chlorine, bromine, iodine,
It may have a halogen atom such as fluorine or an alkyl group having 1 to 4 carbon atoms as a substituent. A) in the presence of a radical polymerization initiator or a cationic polymerization initiator alone or two or more kinds thereof, wherein the benzene ring has an alkyl group having 1 to 4 carbon atoms as a substituent. Hydroxystyrene polymers which may be preferred,
Particularly, a polymer of an unsubstituted benzene ring-containing hydroxystyrene is preferable.

[0010] 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 1,000 to 100,000, particularly preferably 1,500 to 50,000.

If the molecular weights of the novolak resin and the polyvinyl phenol resin are smaller than the above range, a sufficient coating film as a resist cannot be obtained. There is a tendency that the omission of a portion becomes insufficient and it becomes difficult to obtain a resist pattern. In the present invention, (A)
Novolak resins are preferred as components.

In the present invention, the cross-linking agent as the component (B) is used as a photosensitive composition layer of a lithographic printing plate to convert the novolak resin or the polyvinyl phenol resin of the component (A) by the action of an acid generated in an exposed portion. Crosslinking, which has the effect of insolubilizing, therefore, is not particularly limited as long as it can crosslink the resin,
Typically, a methylol group as a functional group, an alkoxymethyl group obtained by subjecting the methyl group to alcohol condensation, and an amino compound having at least two acetoxymethyl groups and the like, specifically, a melamine derivative such as methoxymethyl Melamine [Mitsui Cyanamid Co., Cymel 300 series (1), etc.], benzoguanamine derivative [Methyl / ethyl mixed alkoxylated benzoguanamine resin (Mitsui Cyanamid Co., Cymel 1100 series (2), etc.)], glycoluril derivative [tetramethylol glycol] Examples thereof include uryl resins (manufactured by Mitsui Cyanamid, Cymel 1100 series (3) and the like), urea resin derivatives, resole resins, and the like.

Of these, melamine derivatives are preferred, and from the viewpoint of the preservability of the resulting lithographic printing plate and the ink adhesion, the ratio of the number of alkoxymethyl groups to the total number of methylol groups and alkoxymethyl groups in the melamine derivative is preferably 7
Melamine derivatives having 0% or more, particularly 90% or more are preferred. Such a melamine derivative can be obtained by a known method in which a specific amount of formaldehyde and alcohol are reacted with the melamine derivative under acidic conditions, and the ratio of the alkoxymethyl group can be determined by ¹³ C-NMR.

The near-infrared absorbing agent as the component (C) in the present invention includes, for example, JP-A-6-4363.
No. 3 publication, squarylium-based, cyanine-based,
Various dyes such as merocyanine dyes, croconate dyes, indolizine dyes, pyrylium dyes, polymethine dyes, phthalocyanine dyes, and the like can be mentioned, and among them, cyanine dyes and polymethine dyes are preferable. Cyanine dyes which are indole type cyanine (indocyanine) or thiazole type cyanine (thiocyanine), or polymethine dyes represented by the following general formula (II) are preferable, and the former cyanine dyes are most preferable.

[0015]

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[In the formula (I), R ^{1 to} R ⁸ each independently represent a hydrogen atom, a halogen atom, a nitro group, an alkoxy group, a sulfonic acid or a base thereof, or two adjacent substituents May be linked to each other to form a fused benzene ring, and R ⁹ and R ¹⁰ are each independently an alkyl group optionally having a substituent, an alkenyl group optionally having a substituent, L ¹ represents an alkynyl group which may have a substituent or a phenyl group optionally having a substituent; Y ¹ and Y ² each independently represent a dialkylmethylene group or a sulfur atom; Represents a penta or heptamethine group which may have a substituent, and two substituents on the penta or heptamethine group may be linked to each other to form a cycloalkene ring having 5 to 7 carbon atoms; Z ^1- represents a counter anion Show. ]

[0017]

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[In the formula (II), R ^{11 to} R ¹⁴ each independently represent an alkyl group, and R ¹⁵ and R ¹⁶ each independently represent an aryl group which may have a substituent. , L ²
Represents a mono, tri, or pentamethine group which may have a substituent, and Z ^2- represents a counter anion. ]

In the formula (I), the halogen atom of R ^{1 to} R ⁸ is preferably a chlorine atom, the alkoxy group is preferably a methoxy group, and R ^{1 to} R ⁸ are hydrogen atoms of 4 to 8
It is particularly preferred that the number is one. Further, as R ⁹ and R ¹⁰ , an alkoxy group, an aryloxy group, an acyl group,
Phenyl group, hydroxyl group, halogen atom, carboxyl group,
A sulfonic acid group-substituted or unsubstituted alkyl group, alkyl group, alkenyl group, alkynyl group, alkoxy group, aryloxy group, acyl group, hydroxyl group, halogen atom-substituted or unsubstituted phenyl group, Alkenyl groups and alkynyl groups are preferred, and alkyl groups, allyl groups, hydroxyalkyl groups, phenoxyalkyl groups and phenyl groups are particularly preferred. Further, as Y ¹ and Y ² , a dimethylmethylene group or a sulfur atom is preferable, and a dimethylmethylene group is particularly preferable. The cycloalkene ring for L ¹ is preferably a cyclopentene ring. As the Z ^1-, Cl ^{-,
_{I -, Br -, ClO 4}} -, BF 4 -, PF 6 - include inorganic ions or benzenesulfonic acid, such as, p- toluenesulfonic acid, naphthalene-1-sulfonic acid, an ion of the organic acid such as acetic acid it can, ^in, I ^-, ClO
_{^{4 -, BF 4 -, PF}} 6 -, or p- toluenesulfonic acid ion.

The alkyl group represented by R ^{11 to} R ¹⁴ in the formula (II) usually has 1 to 12 carbon atoms, and specifically includes a methyl group, an ethyl group, an n-propyl group, i-
Propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, cyclopentyl group, cyclohexyl group, etc. No. Also, R
^{As 15} and R ¹⁶ , specifically, a phenyl group, 1-
Substituted with an unsubstituted aryl group such as a naphthyl group, a 2-naphthyl group, a 2-furyl group, a 3-furyl group, a 2-thienyl group, a 3-thienyl group, or an alkyl group such as a tolyl group, a xylyl group, or a furfuryl group; Substituted with a halogen atom such as an aryl group, 2-chlorophenyl group, 4-chlorophenyl group, or 4-bromophenyl group, or substituted with a hydroxyl group such as a 4-hydroxyphenyl group or a 5-hydroxy-2-furyl group. Aryl group, 4-methoxyphenyl group, 4
An aryl group substituted with an alkoxy group such as -ethoxyphenyl group; and an aryl group substituted with a dialkylamino group such as 4-dimethylaminophenyl group and 4-diethylaminophenyl group. L ² is preferably a trimethine group. Examples of Z ²⁻ include the same as those described above for Z ¹⁻ .

Specific examples of the cyanine dye represented by the general formula (I) and the polymethine dye represented by the general formula (II) are shown below.

[0022]

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[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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As the acid generator as the component (D) in the present invention, known acid generators can be used, and known onium salts such as ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, and organic halogens can be used. Examples thereof include a compound, a photoacid generator having an o-nitrobenzyl-type protecting group, and a disulfone compound. Particularly, a trihaloalkyl compound represented by the following general formula (III) and a trihaloalkyl compound represented by the following general formula (IV) The diazonium salt compound used is preferably used.

[0030]

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In the formula (III), X represents a trihaloalkyl group having 1 to 3 carbon atoms, W represents each atom of nitrogen, sulfur, selenium, phosphorus, or carbon, and V represents oxygen, nitrogen, sulfur, S represents selenium or phosphorus, U represents a non-metallic atom group having a chromophore group and required for cyclizing W and V. However, the ring formed by the non-metallic atom group may have the X. ]

[0032]

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[In the formula (IV), R ¹⁷ represents an aryl group;
Z ^3- represents a counter anion. Specifically, for example, as the trihaloalkyl compound represented by the general formula (III), an s-triazine-based compound represented by the following general formula (IIIa);
1,3,4-oxadiazole-based compound represented by b) and α-pyrone-based compound represented by the following general formula (IIIc).

[0034]

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[Formula (IIIa), Formula (IIIb), and Formula (IIIb)
(IIIc), A¹, A^Two, And A ^ThreeHas a substituent
An aryl group or a heterocyclic group which may be¹⁸,
R¹⁹, And R²⁰Is hydrogen atom, halogen atom, alkyl
X or an aryl group;¹, X^TwoAnd X^ThreeIs
A trihaloalkyl group having 1 to 3 carbon atoms, n is 0,
1 or 2. ]

These s-triazine compounds (III
a) a 1,3,4-oxadiazole compound (III
Specific examples of b) and the α-pyrone-based compound (IIIc) are shown below.

[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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As the diazonium salt compound represented by the general formula (IV), a diazonium salt which generates a strong Lewis acid upon exposure is preferable, and an inorganic ion is preferable as a counter anion. Specific examples of such a compound include aromatic diazonium whose counter anion is at least one of phosphorus fluoride ion, arsenic fluoride ion, antimony fluoride ion, antimony chloride ion, tin chloride ion, bismuth chloride ion, or zinc chloride ion. Salts are exemplified, and paradiazophenylamine salts are particularly preferred.

Of these, s-triazine compounds having two or more trihalomethyl groups are more preferred. The dissolution inhibitor as the component (E) in the present invention, which can reduce the dissolution rate of the composition comprising the components (A) to (D) in an alkaline developer, is at least added to the component (A). It must be a compound that suppresses the dissolution rate of the composition comprising (D) to (D) to 80% or less in an alkali developer, but preferably suppresses the dissolution rate to 50% or less, more preferably 30% or less. Compound.

As a simple method for measuring the dissolution inhibiting effect,
For example, first, a predetermined amount of a blend of the components (A), (B), (C) and (D) is applied on a support, and the resultant is immersed in the alkaline developer. The correlation between time and the amount of decrease in film thickness is determined. Next, after adding a predetermined amount of the dissolution inhibitor and the sample to the above-mentioned composition, the mixture is applied with the same film thickness as before, and the relationship between the immersion time and the film thickness reduction amount is similarly determined. Since the dissolution rate ratio between the two can be determined from these measured values, the effect of reducing the dissolution rate of the sample of the dissolution inhibitor used can be measured as its relative speed. As specific examples, examples in which an amount of 20% by weight of the components (A) to (D) and an inhibitor were additionally added are described in Examples.

It has been found that a wide range of compounds can be applied as effective dissolution inhibitors used in the present invention. However, since the dissolution inhibitor must remain stably in the photosensitive layer, it is solid at normal temperature and pressure, or has a boiling point of 180 at normal pressure.
It is preferably a liquid at a temperature of at least ° C. Illustrative of these effective compounds are sulfonic acid esters, phosphoric acid esters, aromatic carboxylic acid esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines and aromatic ether compounds. These can be used alone or in combination of two or more.

Further, they are specifically exemplified by, for example, ethyl benzenesulfonate, benzenesulfonic acid-
n-hexyl, phenyl benzenesulfonate, benzyl benzenesulfonate, phenylethyl benzenesulfonate, ethyl p-toluenesulfonate, t-butyl p-toluenesulfonate, n-octyl p-toluenesulfonate, p-toluene 2-ethylhexyl sulfonic acid, phenyl p-toluenesulfonate, phenylethyl p-toluenesulfonate, ethyl 1-naphthalenesulfonate, phenyl 2-naphthalenesulfonate, benzyl 1-naphthalenesulfonate, phenylethyl 1-naphthalenesulfonate , Sulfonates such as bisphenol A dimethyl sulfonate; trimethyl phosphate, triethyl phosphate, tri (2-ethylhexyl) phosphate, triphenyl phosphate, tritolyl phosphate, tricresyl phosphate, and tri- ( - phosphoric acid esters naphthyl) and the like; benzoic acid, benzoic acid n- heptyl, phenyl benzoate, benzoic acid 1-naphthyl, 1-pyridinecarboxylic acid n- octyl, tris (n- butoxycarbonyl)
Aromatic carboxylic acid esters such as -s-triazine; aromatic disulfones such as diphenyldisulfone, dinaphthyldisulfone and ditolyldisulfone; mono, di or trichloroacetic anhydride, phenylsuccinic anhydride, maleic anhydride, Carboxylic anhydrides such as phthalic anhydride and benzoic anhydride; aromatic ketones such as benzophenone, acetophenone, benzyl and 4,4'-dimethylaminobenzophenone; p-dimethylaminobenzaldehyde, p
Aromatic aldehydes such as -methoxybenzaldehyde, p-chlorobenzaldehyde, 1-naphthaldehyde;
Aromatic amines such as triphenylamine, diphenylamine, tolylamine, diphenylnaphthylamine;
Examples thereof include aromatic ethers such as ethylene glycol diphenyl ether, 2-methoxynaphthalene, diphenyl ether, and 4,4'-diethoxybisphenol A. These compounds may be substituted with a substituent that does not impair the effects of the present invention, such as an alkyl group, an alkoxy group, a halogen atom, and a phenyl group. Furthermore, it may have a structure incorporated in a polymer or a resin, and examples thereof include a novolak resin and a sulfonic acid ester supported on a hydroxyl group of polyvinyl phenol by an ester bond. Gives a deterrent effect.

These dissolution inhibitors are of the type having a structure sensitive to ultraviolet light, such as o-quinonediazide sulfonic acid ester or aromatic sulfone, and can provide good images. Can be. Of these dissolution inhibitors, quinonediazide compounds are preferred. o
The quinonediazide compound comprises at least one o
-Quinonediazide group is preferred, more preferably a compound having an o-benzoquinonediazide group or an o-naphthoquinonediazide group, compounds having various known structures,
For example, J. "Light-Sensit" by Kosar
live Systems "(John Wiley &
Sons, Inc. 1965) pp. 339-35
Includes compounds described in detail on page 3. Particularly, esters of various hydroxyl compounds with o-naphthoquinonediazidosulfonate are preferred. Preferred hydroxyl compounds include a condensation resin of a phenol and a carbonyl group-containing compound, particularly a resin obtained by condensation in the presence of an acidic catalyst. Examples of the phenols include phenol, resorcinol, cresol, and pyrogallol, and examples of the carbonyl group-containing compound include formaldehyde and aldehydes such as benzaldehyde;
Ketones such as acetone are mentioned.

In particular, phenol-formaldehyde resin,
Cresol / formaldehyde resin, pyrogallol / acetone resin, resorcin / benzaldehyde resin are preferred. Typical examples of the o-quinonediazide compound include benzoquinone- (1,2) -diazidosulfonyl chloride or naphthoquinone- (1,2) -diazidosulfonyl chloride with phenol-formaldehyde resin or cresol-formaldehyde resin. Esters, sulfonic acid esters of naphthoquinone- (1,2) -diazidosulfonyl chloride and pyrogallol acetone resin described in U.S. Pat. No. 3,635,709, described in JP-A-56-1044. Condensation product of naphthoquinone- (1,2) -diazide- (2) -5-sulfonyl chloride and resorcin-benzaldehyde resin, naphthoquinone- (1,2) -diazide- described in JP-A-55-76346. (2) -5-sulfonyl chloride and reso Shin - pyrogallol - ester compounds of acetone co-polycondensates, Other useful o- quinonediazide compounds, JP 50-11750
No. 3 obtained by subjecting a polyester having a hydroxyl group at a terminal to an esterification reaction with o-naphthoquinonediazidosulfonyl chloride.
Examples thereof include those obtained by subjecting a homopolymer of p-hydroxystyrene or a copolymer thereof to a copolymerizable monomer with o-naphthoquinonediazidosulfonyl chloride as described in No. 3350 to an esterification reaction.

In the negative photosensitive composition of the present invention, each of the exposed portions has a property that it is difficult to dissolve in an alkali developing solution. In the present invention, however, the action of the dissolution inhibitor is reduced by the addition of a dissolution inhibitor. Although it is unknown, the solubility of at least the blend of components (A) to (D) (corresponding to the unexposed portion) in an alkali developing solution is reduced, while the effect of lowering the solubility in the exposed portion is significantly increased. Therefore, the development contrast between the exposed portion and the unexposed portion is increased, and the film loss of the exposed portion can be suppressed while maintaining the condition in which the unexposed portion can be developed. Therefore, particularly, it is considered that the thinning of the small point is suppressed, and as a result, the small point can be reproduced with a low exposure amount, and the sensitivity becomes high.

The novolak resin or polyvinylphenol resin as the component (A), the crosslinking agent as the component (B), the near-infrared absorber as the component (C), which constitutes the photosensitive composition of the present invention, The ratio of each of the acid generator as the component (D) and the dissolution inhibitor as the component (E) to the photosensitive composition is preferably
The component (A) is 40 to 90% by weight, and the component (B) is 5 to 50% by weight.
% By weight, 0.1 to 50% by weight of the component (C), 0.1 to 40% by weight of the component (D), and 1 to 50% by weight of the component (E). Is 60 to 90% by weight, the component (B) is 10 to 30% by weight, and the component (C) is 0.1% by weight.
5 to 30% by weight, the component (D) is 0.5 to 20% by weight,
The component (E) is 5 to 30% by weight.

The photosensitive composition of the present invention may contain, in addition to the above components, dyes, pigments, coatability improvers, developability improvers, adhesion improvers, sensitivity improvers, sensitizers, etc. Various additives commonly used can be further added.

The photosensitive composition of the present invention is usually applied to the surface of a support as a solution in which each of the above components is dissolved in an appropriate solvent, and then heated and dried to give the photosensitive composition on the surface of the support. It is a photosensitive lithographic printing plate having a layer formed thereon.

Here, the solvent is not particularly limited as long as it has sufficient solubility in the components used and gives good coating properties, but methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl Cellosolve solvents such as 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 such as dipropylene glycol dimethyl ether Glycol solvents, butyl acetate, amyl acetate,
Ethyl butyrate, butyl butyrate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, methyl lactate, ethyl lactate, 3-
Ester solvents such as methyl methoxypropionate, alcohol solvents such as heptanol, hexanol, diacetone alcohol and furfuryl alcohol, ketone solvents such as cyclohexanone and methyl amyl ketone, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like A highly polar solvent, a mixed solvent thereof, and a solvent obtained by adding an aromatic hydrocarbon to the mixed solvent 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, there are conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, and the like.
And curtain coating can be used. The coating amount varies depending on the application, but is usually 0.1 to 1 as a dry film thickness.
It is preferred to be in the range of about 0 g / m ² . The drying temperature is usually 20 to 150 ° C., preferably 30 to 150 ° C.
A range of about 100 ° C. is adopted.

The support may be a metal plate such as aluminum, zinc, copper or steel, aluminum, zinc, or the like.
Copper, iron, chromium, nickel, etc. plated or evaporated metal plate, paper, resin coated paper, paper with aluminum or other metal foil attached, plastic film, hydrophilized plastic film, glass plate, etc. No. Among them, an aluminum plate is preferable, and surface treatments such as graining treatment by electrolytic etching or brush polishing in a hydrochloric acid or nitric acid solution, anodizing treatment in a sulfuric acid solution, and, if necessary, sealing treatment are performed. A coated aluminum plate is more preferred.

The light source for imagewise exposing the photosensitive lithographic printing plate of the present invention is a light source for generating a near infrared laser beam of 650 to 1100 nm, for example, a ruby laser,
A solid-state laser such as a YAG laser, a semiconductor laser, and the like can be given. In particular, a small-sized and long-life semiconductor laser is preferable. Usually, after scanning exposure with these laser light sources, a post-heating treatment (post-exposure baking; hereinafter, sometimes abbreviated as PEB) is preferably performed, and then developed with a developer to form an image.

The temperature of the PEB is usually 50 to
A range of 200 ° C, preferably about 90 to 160 ° C is employed. Further, as the developer, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, dibasic sodium phosphate, 0.1 to 0.1 of alkali metal salts such as tertiary sodium phosphate. An alkali developer comprising an aqueous solution of about 20% by weight is preferred. In addition, an anionic surfactant, an amphoteric surfactant, or the like, or an organic solvent such as alcohol can be added to the developer as needed.

[0060]

EXAMPLES Hereinafter, the present invention will be described more specifically by way of examples.
The present invention will be described below unless the gist of the invention is exceeded.
It is not limited to the embodiment. Examples 1 and 2, Comparative Example 1 An aluminum plate (0.24 mm thick) was treated with 3% by weight of hydroxyl.
After performing a degreasing treatment in a sodium chloride bath, 12 g / l
25 ° C., 80 A / dm in a hydrochloric acid bath having a concentration of torr ^TwoCurrent
Perform an electrolytic etching treatment at a density of 10 seconds, wash with water,
50 ° C. in a sodium hydroxide bath at a concentration of 0 g / l
Desmut treatment for 3 seconds, wash with water, and then 30% by weight sulfuric acid bath
30 ° C, 10A / dm in^TwoAnode for 15 seconds at a current density of
An oxidation treatment was performed. Furthermore, sealed with hot water at 90 ° C and pH 9
Aluminum plate for lithographic printing plate after perforating, washing and drying
I got

[0061] The obtained aluminum plate surface, (A) component as novolak resin Al (phenol / m- cresol / p- cresol = 5/3/2 was polycondensed with formaldehyde resin, M _W 7,500, Mn900 ) 50
Part by weight and novolak resin A2 (resin obtained by polycondensation of phenol with formaldehyde, M _W 6,100, M _n 900)
50 parts by weight, 20 parts by weight of methoxymethylated melamine (Cymel 300, manufactured by Mitsui Synamid Co.) as the component (B), and a cyanine dye (I-14) as the component (C)
(CY-10, manufactured by Nippon Kayaku Co., Ltd.) 5 parts by weight, 2,4-bis (trichloromethyl) -6-p-methoxystyryl s-triazine 5 parts by weight as the component (D), pyrogallol acetone as the component (E) resin 20 (M _W 2500) of o- quinonediazide-5-sulfonic acid ester (OH group
% Is esterified), the number of parts shown in Table 1 below, and Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 1
A photosensitive lithographic printing plate having a photosensitive composition layer having a dried film thickness of 2.5 g / m ² is prepared by applying a coating solution in which 1000 parts by weight of cyclohexanone is dissolved by using a wire bar and drying. did.

For each of the resulting photosensitive lithographic printing plates,
Laser exposure machine (Crend, Trendsette
r) Exposure was performed by changing the exposure energy, and after post-heating (PEB) treatment at each temperature shown in Table 1 for 1 minute, a developer (Konica Corporation PS plate developer, 5-fold dilution of SDR-1) ) At 25 ° C. At this time, the exposure amount at which a small point of 3% (200 lines / inch) was reproduced was measured. The results are shown in Table 1.

[0063]

[Table 1] In addition, the dissolution inhibiting effect of the used quinonediazide compound obtained by the following formula is 0.20.

[0064]

(Equation 1) However, the types and mixing ratios of the components in the formula are the same as in Example 2.

[0065]

According to the present invention, there is provided a photosensitive composition and a photosensitive lithographic printing plate capable of obtaining a photosensitive lithographic printing plate having high sensitivity in the near-infrared region and having no small dots. be able to.

Claims (6)

[Claims] 1. The following (A), (B), (C),
A photosensitive composition comprising (D) and (E). (A) at least one resin selected from the group consisting of a novolak resin and a polyvinylphenol resin; (B) a resin cross-linking agent for the component (A); (C) a near-infrared absorber; (D) an acid generator; ) To (D), a dissolution inhibitor capable of reducing the dissolution rate in an alkaline developer 2. The photosensitive composition according to claim 1, wherein the component (A) is a novolak resin. 3. The photosensitive composition according to claim 1, wherein the component (B) is a melamine derivative. 4. The photosensitive composition according to claim 1, which comprises a cyanine dye represented by the following general formula (I) as the component (C). Embedded image [In the formula (I), R ^{1 to} R ⁸ each independently represent a hydrogen atom,
A halogen atom, a nitro group, an alkoxy group, a sulfonic acid or a base thereof, or two adjacent substituents may be connected to each other to form a fused benzene ring;
R ⁹ and R ¹⁰ 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 substituent Y ¹ and Y ² each independently represent a dialkylmethylene group or a sulfur atom, and L ¹ represents a penta or heptamethine group which may have a substituent. Wherein the two substituents on the penta or heptamethine group are linked together to form
May form a cycloalkene ring, and Z ^1- represents a counter anion. ] 5. The photosensitive composition according to claim 1, wherein the dissolution inhibitor is a quinonediazide compound. 6. A photosensitive lithographic printing plate comprising a support and a layer comprising the photosensitive composition according to claim 1 formed on the surface of the support.