JP2000330271A - Positive photosensitive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive photosensitive composition having high sensitivity to infrared laser beams and excellent development latitude and storage stability. SOLUTION: The positive photosensitive composition contains a polymer compound having acid groups and an infrared absorber represented by a general formula 1, and this composition has limited solubility in an aqueous alkaline solution before irradiation with infrared rays and becomes soluble in an aqueous alkaline solution by irradiation with infrared rays. In the formula 1, each of X and Y is an O, S, Se, or Te atom; M is a methine chain having conjugated >=5C atoms; each of Rx1-Rx4 and Ry1-Ry4 is an H or halogen atom or a cyano group or the like and W is an anion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive composition suitable as a positive type image forming material, and more particularly to a so-called direct plate making which can be written by an infrared laser and can be made directly from a digital signal of a computer or the like. The present invention relates to a positive photosensitive composition suitable for a lithographic printing plate material.

[0002]

2. Description of the Related Art In recent years, with the development of solid-state lasers and semiconductor lasers having an emission region from near infrared to infrared, as a system for directly making a plate from digital data of a computer,
Attention is paid to those using these infrared lasers.
WO97 / 3 shows that a composition using a cyanine-based infrared-absorbing dye as an alkali-water-soluble polymer dissolution inhibitor as an infrared laser-compatible image forming material exhibits a positive effect.
9894. This positive action is an action in which the infrared absorbing dye absorbs the laser beam and the generated heat causes the effect of suppressing the dissolution of the polymer film at the irradiated portion to disappear, thereby forming an image. Although the image forming property is sufficient on the laser-irradiated surface of the light-sensitive material, a sufficient effect cannot be obtained up to the deep part of the light-sensitive material due to thermal diffusion. There was a problem that it was difficult to turn off the image and a good image could not be obtained (low sensitivity, narrow development latitude).
Here, the development latitude indicates an allowable range in which a good image can be formed when the alkali concentration of the alkali developer is changed. In addition, there is a problem that sensitivity fluctuation before and after storage in a high temperature environment, that is, storage stability is poor.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention enables direct plate making by recording from digital data of a computer or the like using a solid-state laser and a semiconductor laser that emit infrared light, has high sensitivity to the infrared laser, and has development latitude and storage. An object of the present invention is to provide a positive photosensitive composition having good stability.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies for the purpose of improving image forming properties (sensitivity and development latitude) and storage stability. As a result, it was found that it was possible to form an image having high discrimination (a large difference in dissolution rate between exposed and unexposed portions), and completed the present invention. Although the reason is not clear, it is considered that the efficiency of converting light into heat (photothermal conversion efficiency) is higher than that of cyanine-based dyes or the like because a specific terminal group (pyrylium) is used. The means for solving the above problems are as follows. That is, <1> contains a polymer compound having an acidic group and an infrared absorbent represented by the following general formula (1), and has a reduced alkali aqueous solution solubility before infrared irradiation. It is a positive photosensitive composition characterized by being soluble.

[0005]

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(In the general formula (1), X and Y each represent an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. M represents a methine chain having 5 or more conjugated carbon atoms.)
x _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ may be the same or different, and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thio group, Represents a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. W ^- represents an anion. )

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the positive photosensitive composition of the present invention will be described in detail. The positive photosensitive composition of the present invention contains at least a polymer compound having an acidic group and the infrared absorbent represented by the general formula (1), and further contains other components as necessary. Do it. The polymer compound having an acidic group is insoluble in water, and
It is a polymer compound soluble in an aqueous alkaline solution. Hereinafter, the polymer compound having an acidic group is referred to as “alkali-soluble polymer”. The solubility of the positive photosensitive composition of the present invention in an aqueous alkali solution before infrared irradiation is suppressed due to the action of the infrared absorber, and the positive photosensitive composition becomes soluble in the alkaline aqueous solution by infrared irradiation.

[Infrared absorber represented by general formula (1)]
The positive photosensitive composition of the present invention contains an infrared absorbent represented by the following general formula (1).

[0009]

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In the general formula (1), X and Y each represent a chalcogen atom, and each represents an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. Oxygen atoms and sulfur atoms are preferred because they are synthetically easy, and oxygen atoms are particularly preferred from the interaction with the alkali-soluble polymer.

In the general formula (1), M represents a conjugated carbon number of 5
It represents the above methine chain and may have a substituent or a ring structure. Since the number of conjugated carbon atoms is related to the absorption wavelength, 5 to 13 is preferable and 5, 7, and 9 are particularly preferable for infrared laser. The methine chain preferably has a substituent in terms of solvent solubility. Examples of the substituent include a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, and a thio group. , A sulfonyl group, a sulfinyl group, an oxy group, an amino group, and the like, and a halogen atom, an alkyl group, an aryl group, a thio group, an amino group, and an oxy group are particularly preferred. Specific examples of these substituents include Rx ₁
-Rx ₄ , and the same as the specific examples of the substituents represented by Ry _{1 to} Ry ₄ . The substituent is particularly preferably an alkyl group having 2 or more carbon atoms or a substituted alkyl group, and is more preferably a linear group than a ring structure. In addition, it is preferable that the substituent is present at the α-position of the pyrylium nucleus in particular, because it has good compatibility with the alkali-soluble polymer, has little adsorption to the substrate, and is hardly stained.

M is a pentamethine chain having 5 conjugated carbon atoms, and an infrared absorber represented by the following general formula (2) is most preferable for a laser having an exposure wavelength of 830 nm.

[0013]

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In the general formula (2), A and B represent a substituent, and as the substituent, an alkyl group and an aryl group are particularly preferable. Specific examples of the alkyl group and aryl group are the same as specific examples of the substituent represented by Rx ₁ to Rx _4, and Ry ₁ to Ry ₄ to be described later.

In the general formula (1), Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ may be the same or different, and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group,
Represents an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group, which may have a substituent.

Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
When each represents an alkyl group, examples of the alkyl group include a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms. Specifically, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, Eicosyl group, isopropyl group,
Isobutyl, s-butyl, t-butyl, isopentyl, neopentyl, 1-methylbutyl, isohexyl, 2-ethylhexyl, 2-methylhexyl, cyclohexyl, cyclopentyl, 2-norbornyl, etc. No. Among these, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms, and a cyclic alkyl group having 5 to 10 carbon atoms are more preferable.

These alkyl groups may have a substituent, and examples of the substituent include monovalent nonmetallic atomic groups except hydrogen. Preferred examples include a halogen atom (-F, -Br, -C1, -I), a hydroxyl group, an alkoxy group, an aryloxy group, a mercapto group, an alkylthio group, an arylthio group, an alkyldithio group, an aryldithio group, an amino group, N-alkylamino group, N, N-
Dialkylamino group, N-arylamino group, N, N-
Diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyl An oxy group, an N-alkyl-N-arylcarbamoyloxy group, an alkylsulfoxy group, an arylsulfoxy group, an acylthio group,
Acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-
Arylureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-
Alkylureido group, N-arylureido group, N'-
Alkyl-N-alkylureido group, N′-alkyl-
N-arylureido group, N ′, N′-dialkyl-N
-Alkylureido group, N ', N'-dialkyl-N-
Arylureido group,

N'-aryl-N-alkylureido groups, N'-aryl-N-arylureido groups, N ',
An N′-diaryl-N-alkylureido group, N ′,
An N′-diaryl-N-arylureido group, an N′-alkyl-N′-aryl-N-alkylureido group,
An N′-alkyl-N′-aryl-N-arylureido group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, an N-alkyl-N-alkoxycarbonylamino group, an N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl group, and conjugate base group thereof (hereinafter, “carboxylate”
That. ), Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl Group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfo group (-
SO ₃ H) and its conjugate base group (hereinafter referred to as “sulfonato group”), alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, An N-arylsulfinamoyl group, an N, N-diarylsulfinamoyl group, an N-alkyl-N-arylsulfinamoyl group, a sulfamoyl group, an N-alkylsulfamoyl group,

N, N-dialkylsulfamoyl group, N
-Arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, N-acylsulfamoyl group and its conjugate base group, N-alkylsulfonylsulfamoyl group (-SO
₂ NHSO ₂ R, R represents an alkyl group. ) And its conjugate base group, N-arylsulfonylsulfamoyl group (-
SO ₂ NHSO ₂ Ar and Ar represent an aryl group. ) And its conjugated base group, N- alkylsulfonylcarbamoyl group (-CONHSO ₂ R, R represents an alkyl group.) And a conjugated base group, N- aryl sulfonyl carbamoyl group (-CONHSO ₂ Ar, Ar is an aryl group And its conjugated base group and alkoxysilyl group (-S
i (OR) ₃ and R represent an alkyl group. ), An aryloxysilyl group (—Si (OAr) ₃ , Ar represents an aryl group), a hydroxysilyl group (—Si (OH) ₃ ) and its conjugate base group, a phosphono group (—PO ₃ H ₂ ) and The conjugate base group (hereinafter, referred to as “phosphonato group”), a dialkylphosphono group (—PO ₃ R ₂ , R represents an alkyl group), a diarylphosphono group (—PO ₃ Ar ₂ , Ar represents an aryl group) the represented.), alkyl aryl phosphono group _{(-PO 3 (R) (Ar} ), R is an alkyl group, Ar. represents an aryl group) monoalkyl phosphono group (-PO ₃
H (R) and R represent an alkyl group. ) And its conjugated base group (hereinafter referred to as “alkylphosphonate group”),

A monoarylphosphono group (—PO ₃ H (A
r) and Ar represent an aryl group. ) And its conjugate base group (hereinafter referred to as “arylphosphonato group”), its phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as “phosphonatooxy group”), its dialkylphosphonooxy group ( —OPO ₃ (R) ₂ , R represents an alkyl group), a diarylphosphonooxy group (—OPO 3
₃ (Ar) ₂ and Ar represent an aryl group. ), An alkylarylphosphonooxy group (—OPO ₃ (R) (Ar),
R represents an alkyl group and Ar represents an aryl group. ), A monoalkylphosphonooxy group (—OPO ₃ H (R), R represents an alkyl group) and its conjugate base group (hereinafter, referred to as “alkylphosphonatooxy group”), a monoarylphosphonooxy group (—OPO ₃ H (Ar) Ar represents an aryl group) and its conjugate base group (hereinafter, referred to as “arylphosphonatooxy group”), cyano group, nitro group,
Examples include an aryl group, an alkenyl group, and an alkynyl group.

Specific examples of the alkyl group in these substituents include the alkyl groups represented by Rx _{1 to} Rx ₄ and Ry _{1 to} Ry _4. Specific examples of the aryl group include a phenyl group , Biphenyl, naphthyl, tolyl, xylyl, mesityl, cumenyl, fluorophenyl, chlorophenyl, bromophenyl, chloromethylphenyl, hydroxyphenyl, methoxyphenyl, ethoxyphenyl, phenoxyphenyl , Acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group,
Methylaminophenyl group, dimethylaminophenyl group,
Acetylaminophenyl, carboxyphenyl, methoxycarbonylphenyl, ethoxycarbonylphenyl, phenoxycarbonylphenyl, N-phenylcarbamoylphenyl, nitrophenyl, cyanophenyl, sulfophenyl, sulfonatophenyl, phosphono Examples include a phenyl group and a phosphonatophenyl group. Specific examples of the alkenyl group in the above substituent include a vinyl group, a 1-propenyl group, a 1-butenyl group, a cinnamyl group, a 2-chloro-1-ethenyl group, and the like. Specific examples of the alkynyl group include Examples thereof include an ethynyl group, a 1-propynyl group, a 1-butynyl group, a trimethylsilylethynyl group, and a phenylethynyl group. In addition, the acyl group (R ¹ CO
As-), R ¹ represents a hydrogen atom, the above-mentioned alkyl group,
Those which are an aryl group, an alkenyl group, or an alkynyl group are mentioned.

Among these substituents, more preferred are a halogen atom (-F, -Br, -C1, -I), an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an N-alkylamino group, , N-dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, formyl group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N- Alkylcarbamoyl group, N, N-
Dialkylcarbamoyl, N-arylcarbamoyl, N-alkyl-N-arylcarbamoyl, sulfo, sulfonato, sulfamoyl, N-alkylsulfamoyl, N, N-dialkylsulfamoyl, N-aryl Sulfamoyl group, N-alkyl-N
-Arylsulfamoyl group, phosphono group, phosphonate group, dialkylphosphono group, diarylphosphono group, monoalkylphosphono group, alkylphosphonate group, monoarylphosphono group, arylphosphonate group, phosphonooxy group, phosphonatoxy group , An aryl group, an alkenyl group and the like.

On the other hand, examples of the alkylene group in the substituted alkyl group include those obtained by removing any one of the above hydrogen atoms on the alkyl group having 1 to 20 carbon atoms to obtain a divalent organic residue. Preferably, a linear alkylene group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms, and a cyclic alkylene group having 5 to 10 carbon atoms are exemplified. Preferred specific examples of the substituted alkyl group obtained by combining the substituent and an alkylene group include chloromethyl group, bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxymethyl group, methoxyethoxyethyl group, and allyl. Oxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N-cyclohexylcarbamoyloxyethyl group, N- Phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group,

Carboxypropyl, methoxycarbonylethyl, methoxycarbonylmethyl, methoxycarbonylbutyl, allyloxycarbonylbutyl,
Chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylgarbamoylmethyl group, N- (methoxyphenyl) galbamoylethyl group, N-methyl-N- (sulfophenyl) galva Moylmethyl group, sulfopropyl group,
Sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N
-Dipropylsulfamoylpropyl group, N-tolylsulfamoylpropyl group, N-methyl-N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphospho Nopropyl group, methylphosphonobutyl group, methylphosphonatobutyl group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonatooxybutyl group, benzyl group, phenethyl group, α-methylbenzyl Group, 1-methyl-1-phenylethyl group, p-methylbenzyl group, cinnamyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl Group, 2-butynyl group, 3-butynyl group and the like. .

The above Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
When each represents an aryl group, examples of the aryl group include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Examples thereof include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenabutenyl group, a fluorenyl group and the like. Among these, a phenyl group and a naphthyl group are more preferred.

The above Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
In the case of representing a substituted aryl group, examples of the substituted aryl group include those having a monovalent nonmetallic atomic group other than hydrogen as a substituent on a ring-forming carbon atom of the aryl group. Preferred examples of the substituent include the alkyl group, the substituted alkyl group, and the substituents described above for the substituted alkyl group. Preferred specific examples of such a substituted aryl group include a biphenyl group, a tolyl group, a xylyl group, a mesityl group, a cumenyl group, a chlorophenyl group, a bromophenyl group, a fluorophenyl group, a chloromethylphenyl group, a trifluoromethylphenyl group,
Hydroxyphenyl, methoxyphenyl, methoxyethoxyphenyl, allyloxyphenyl, phenoxyphenyl, methylthiophenyl, tolylthiophenyl, phenylthiophenyl, ethylaminophenyl, diethylaminophenyl, morpholinophenyl, acetyl Oxyphenyl group, benzoyloxyphenyl group, N-cyclohexylcarbamoyloxyphenyl group, N-phenylcarbamoyloxyphenyl group,
Acetylaminophenyl group, N-methylbenzoylaminophenyl group, carboxyphenyl group,

Methoxycarbonylphenyl, allyloxycarbonylphenyl, chlorophenoxycarbonylphenyl, galbamoylphenyl, N-methylgalbamoylphenyl, N, N-dipropylcarbamoylphenyl, N- (methoxyphenyl) galva Moylphenyl group, N-methyl-N- (sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoylphenyl group, N-ethylsulfamoylphenyl group, N, N-dipropylsulfamoyl Phenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phosphonophenyl group, phosphonatophenyl group, diethylphosphonophenyl group, diphenylphosphonophenyl group , Lephosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group, tolylphosphonatophenyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallylphenyl group, 2-methylpropenylphenyl Group, 2-propynylphenyl group, 2-butynylphenyl group, 3-butynylphenyl group and the like.

The above Rx₁~ Rx_Four, And Ry₁~ Ry_FourBut,
Alkenyl, substituted alkenyl, alkynyl, respectively
Or a substituted alkynyl group (—C (R^Two) = C (R^Three)
(R ^Four), -C≡C (R^Five)), The R^Two,
R^Three, R^Four, And R^FiveRepresents a monovalent nonmetallic atomic group
Represent. The R^Two, R^Three, R^Four, And R^FiveAs a preferred example of
Is a hydrogen atom, halogen atom, alkyl group, substituted alkyl
And aryl groups, and substituted aryl groups.
As these specific examples, those shown as the above examples are
Similarly mentioned. The R^Two, R^Three, R^Four, And R^FiveEspecially
Preferred examples include a hydrogen atom, a halogen atom and a carbon atom.
Linear, branched and cyclic alkyl groups having 1 to 10 children
I can do it.

Specific examples of R ² , R ³ , R ⁴ , and R ⁵ include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl. Group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, otatadecyl group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, t
-Butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenyl group, 2
-Propynyl group, 2-butynyl group, 3-butynyl group, benzyl group, phenethyl group, α-methylhensyl group, 1-
Methyl-1-phenethyl group, p-methylbenzyl group, cinnamyl group, hydroxyethyl group, methoxyethyl group,
Phenoxydiethyl, allyloxyethyl, methoxyethoxyethyl, ethoxyethoxyethyl,

Morpholinoethyl, morpholinopropyl, sulfopropyl, sulfonatopropyl, sulfobutyl, sulfonatobutyl, carboxydimethyl,
Carboxydiethyl, carboxypropyl, methoxycarbonylethyl, 2-ethylhexyloxycarbonylethyl, phenoxycarbonylmethyl, methoxycarbonylpropyl, N-methylcarbamoylethyl, N, N-ethylaminocarbamoylmethyl, N
-Phenylcarbamoylpropyl group, N-tolylsulfamoylbutyl group, P-trienesulfonylaminopropyl group, benzoylaminohexyl group, phosphonomethyl group, phosphonoethyl group, phosphonopropyl group, p
-Phosphonobenzylaminocarbonylethyl group, phosphonatomethyl group, phosphonatopropyl group, phosphonatobutyl group, p-phosphonatobenzylaminocarbonylethyl group, vinyl group and ethynyl group.

Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
When each represents a substituted carbonyl group (R ⁶ CO—),
R ⁶ represents a monovalent nonmetallic atomic group. Preferred examples of the substituted carbonyl group include a formyl group, an acyl group, a carboxyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an N-alkylcarbamoyl group, an N, N-dialkylcarbamoyl group, an N-arylcarbamoyl group, An N, N-diarylcarbamoyl group and an N-alkyl-N-arylcarbamoyl group are exemplified. As the alkyl group and the aryl group in these, the above-mentioned alkyl group, substituted alkyl group, aryl group,
And substituted aryl groups.
Among these, more preferred substituted carbonyl groups include formyl group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, galbamoyl group, N-alkylgalbamoyl group, N, N-dialkylcarbamoyl group, N- An arylcarbamoyl group is mentioned, and particularly preferred are a formyl group, an acyl group, an alkoxycarbonyl group, and an aryloxycarbonyl group. Specific examples of preferred substituted carbonyl groups include formyl group, acetyl group, benzoyl group, carboxyl group, methoxycarbonyl group, allyloxycarbonyl group, N-methylcarbamoyl group, N-phenylcarbamoyl group, N, N-diethylcarbamoyl group And a morpholinocarbonyl group.

Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
If a substituted thio group (R ⁷ S-), wherein R ⁷ represents a monovalent nonmetallic atom group exclusive of hydrogen. Examples of preferred substituted thio groups include alkylthio, arylthio, alkyldithio, aryldithio, and acylthio groups. Alkyl group in these, the aryl group, the above alkyl group, a substituted alkyl group, an aryl group, and include those exemplified as the substituted aryl group, R ¹ in the acyl group (R ¹ CO-) in the acylthio group
Is as described above. Among these, an alkylthio group and an arylthio group are more preferred. Preferred specific examples of the substituted thio group include a methylthio group, an ethylthio group,
Examples include a phenylthio group, an ethoxyethylthio group, a carboxyethylthio group, and a methoxycarbonylthio group.

Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
When it represents a substituted sulfonyl group (R ⁸ SO ₂ —), the above R ⁸
Represents a monovalent nonmetallic atomic group. More preferred examples include an alkylsulfonyl group and an arylsulfonyl group. Examples of the alkyl group and the aryl group in these include those exemplified above as the alkyl group, the substituted alkyl group, the aryl group, and the substituted aryl group. Specific examples of the substituted sulfonyl group include a butylsulfonyl group and a chlorophenylsulfonyl group.

Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
In the case of representing a substituted sulfinyl group (R ⁹ SO—), the aforementioned R ⁹
Represents a monovalent nonmetallic atomic group. A preferred example is
Alkylsulfinyl group, arylsulfinyl group, sulfinamoyl group, N-alkylsulfinamoyl group,
N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group. Examples of the alkyl group and the aryl group in these include those exemplified above as the alkyl group, the substituted alkyl group, the aryl group, and the substituted aryl group. Among these, more preferred examples include an alkylsulfinyl group and an arylsulfinyl group. Specific examples of such a substituted sulfinyl group include a hexylsulfinyl group, a benzylsulfinyl group, and a tolylsulfinyl group.

Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
If a substituted oxy group (R ¹⁰ O-), wherein R ¹⁰ represents a monovalent nonmetallic atom group exclusive of hydrogen. Preferred substituted oxy groups include an alkoxy group, an aryloxy group, an acyloxy group, a carbamoyloxy group, an N-alkylcarbamoyloxy group, an N-arylcarbamoyloxy group,
N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group,
Examples include an arylsulfoxy group, a phosphonooxy group, and a phosphonatoxy group. Examples of the alkyl group and the aryl group in these include those exemplified above as the alkyl group, the substituted alkyl group, the aryl group, and the substituted aryl group.

As the acyl group (R ¹ CO—) in the acyloxy group, those in which R ¹ has been exemplified as the aforementioned alkyl group, substituted alkyl group, aryl group, and substituted aryl group can be mentioned. Among these substituted oxy groups, an alkoxy group, an aryloxy group, an acyloxy group, and an arylsulfoxy group are more preferred. Specific examples of preferred substituted oxy groups include methoxy, ethoxy, propyloxy, isopropyloxy, butyloxy, pentyloxy, hexyloxy,
Dodecyloxy group, benzyloxy group, allyloxy group, phenethyloxy group, carboxyethyloxy group,
Methoxycarbonylethyloxy group, ethoxycarbonylethyloxy group, methoxyethoxy group, phenoxyethoxy group, methoxyethoxyethoxy group, ethoxyethoxyethoxy group, morpholinoethoxy group, morpholinopropyloxy group, allyloxyethoxyethoxy group, phenoxy group, tolyloxy group , Xylyloxy, mesityloxy, cumenyloxy, methoxyphenyloxy, ethoxyphenyloxy, chlorophenyloxy, bromophenyloxy, acetyloxy, benzoyloxy, naphthyloxy, phenylsulfonyloxy, phosphonooxy, phosphonatoxy And the like.

Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are
In the case of representing a substituted amino group (R ¹¹ NH—, (R ¹² ) (R ¹³ ) N—), R ¹¹ , R ¹² , and R ¹³ each represent a monovalent nonmetallic atomic group excluding hydrogen. Preferred examples of the substituted amino group include an N-alkylamino group, an N, N-dialkylamino group, an N-arylamino group, an N, N-diarylamino group, an N-alkyl-N-arylamino group, an acylamino group, N-alkylacylamino group, N
An arylacylamino group, a ureido group, an N′-alkylureido group, an N ′, N′-dialkylureido group,
N'-arylureido group, N ', N'-diarylureido group, N'-alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido Group, N'-
Alkyl-N-arylureido group, N ′, N′-dialkyl-N-alkylureido group, N ′, N′-dialkyl-N-arylureido group, N′-aryl-N-
Alkyl ureido group, N′-aryl-N-aryl ureide group, N ′, N′-diaryl-N-alkyl ureide group, N ′, N′-diaryl-N-aryl ureide group, N′-alkyl-N ′ -Aryl-N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl —N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group and N-aryl-N-aryloxycarbonylamino group.

Examples of the alkyl group and the aryl group in these groups include those exemplified as the alkyl group, the substituted alkyl group, the aryl group, and the substituted aryl group, and include an acylamino group, an N-alkylacylamino group,
An acyl group (R ¹ C) in the aryl-acylamino group;
R ^{1 in} O-) is as described above. Of these, more preferred are N-alkylamino group, N,
Examples include an N-dialkylamino group, an N-arylamino group, and an acylamino group. Specific examples of preferred substituted amino groups include a methylamino group, an ethylamino group, a diethylamino group, a morpholino group, a piperidino group, a pyrrolidino group, a phenylamino group, a benzoylamino group, and an acetylamino group.

The substituents represented by Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ are preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, and an oxy group. Excellent in solubility, stability, etc.

[0040] In the general formula (1), W ^- (. Which hereinafter may be referred to as a "counter anion") represents a monovalent or polyvalent anion. W ⁻ may be any anion as long as it is an anion, but is preferably an anion having low nucleophilicity. Specific examples of W ⁻ include, for example, halogen ions, ClO ₄ ⁻ , I
O ₄ ⁻ , BF ₄ ⁻ , Ph ₄ B ⁻ , SO ₄ ²⁻ , carbonate (C
F ₃ CO ₃ ^-, etc.), alkyl sulfonates (methanesulfonate), aryl sulfonates (p- toluenesulfonate, etc.), SbCl ₆ ^-, and the like. Here, examples of the alkyl group in the alkyl sulfonate and the aryl group in the aryl sulfonate include those exemplified above as the alkyl group, the substituted alkyl group, the aryl group, and the substituted aryl group. Among these, preferred counter anion, ClO ₄ ^- in decomposing and which generates heat, sulfonates, organic salts as a carboxylic acid salt as,
Those which are easily compatible with the alkali-soluble polymer can be given.

The cationic dye skeleton of the infrared absorbing agent represented by the general formula (1) is a pyrylium salt dye, but the positive charge of the dye is delocalized. Represents the structure.

[0042]

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Hereinafter, specific examples of the cationic dye skeleton of the infrared absorbent represented by the general formula (1) are shown, but the present invention is not limited to these specific examples.

[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[Synthesis Example] The infrared absorbent represented by the general formula (1) can be synthesized by using the method described in JP-A-61-26044. That is, as shown in the following scheme, the compound can be synthesized by condensing a pyrylium nucleus and a methine chain source.

[0059]

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(Synthesis Example 1)-Infrared absorber IR-8-7
・ ClO_Four ^-Synthesis of pyrylium nucleus S-1 (0.01 mol) and methine chain
Source S-2 (0.005 mol) was combined with 15 ml of acetic anhydride.
Mix and heat at 120 ° C. for 30 minutes. Vinegar to this mixture
Sodium acid (0.012 mol)
After acetic anhydride was added, the mixture was heated at 120 ° C. for 40 minutes.
The reaction product is put into 100 ml of water, and the precipitated solid is filtered.
I took it. After washing well with water, further wash with hexane
Infrared absorber IR-8-7.ClO_Four ^-(Λ
max 792 nm in CH _ThreeCN). The reaction formula is
Shown below.

[0061]

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(Synthesis Example 2) Infrared absorbing agent IR-8-2
· ClO ₄ ^- Synthesis of - in Synthesis Example 1, except for changing the pyrylium nuclei S-1 to pyrylium nucleus S-3 is in the same manner as in Synthesis Example 1, an infrared absorbent IR-8-2 · ClO ₄ ^- and (Λmax 8
13nm in CH ₃ OH). The reaction formula is shown below.

[0063]

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In the present invention, these infrared absorbers are used in an amount of from 0.01 to 0.01% based on the total solid content of the positive photosensitive composition.
50% by weight, preferably 0.1 to 20% by weight, more preferably 0.5 to 15% by weight. If the addition amount is less than 0.01% by weight, an image cannot be formed with the positive photosensitive composition,
When added in an amount exceeding 50% by weight, when used as a photosensitive layer of a lithographic printing plate precursor, stains may occur on non-image areas.

The positive photosensitive composition of the present invention may further contain, in addition to the infrared absorbent, as long as the effects of the present invention are not impaired.
Other pigments or dyes having an infrared absorbing property can be added. Examples of the pigment include commercially available pigments and color index (CI) handbook, "Latest Pigment Handbook"
(Edited by Japan Pigment Technology Association, 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), and “Printing Ink Technology”, CMC Publishing, 1984) can be used.

Examples of the pigments include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and polymer-bound pigments. . Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like.

These pigments may be used without being subjected to a surface treatment, or may be used after being subjected to a surface treatment. Examples of the surface treatment include a method of surface-coating a resin or wax, a method of attaching a surfactant, and a method of binding a reactive substance (for example, a silane coupling agent, an epoxy compound, or a polyisocyanate) to the pigment surface. Can be considered. The above surface treatment methods are described in "Properties and Applications of Metallic Soap" (Koshobo),
It is described in "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986).

The particle size of the pigment is preferably 0.01 to 10 μm, more preferably 0.05 to 1 μm, and 0.1 to 10 μm.
1 μm is particularly preferred. The particle size of the pigment is 0.01 μm
When it is less than 10 μm, it is not preferable in terms of stability of the dispersion in the coating solution of the photosensitive layer, and when it exceeds 10 μm, it is not preferable in terms of uniformity of the photosensitive layer. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

Examples of the dye include commercially available dyes and literatures (for example, “Dye Handbook” edited by The Society of Synthetic Organic Chemistry, Showa 45)
Known publications described in the annual publication can be used. Specific examples include azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, and cyanine dyes. In the present invention, among these pigments or dyes, those that absorb infrared light or near-infrared light are particularly preferable because they are suitable for use in lasers that emit infrared light or near-infrared light.

As such a pigment that absorbs infrared light or near infrared light, carbon black is preferably used. Further, examples of dyes that absorb infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829,
Cyanine dyes described in JP-A-60-78787, JP-A-58-173696, JP-A-58-18
1690, methine dyes described in JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187,
JP-A-59-73996, JP-A-60-52940
Naphthoquinone dyes described in JP-A-60-63744, squarylium dyes described in JP-A-58-112792, etc., British Patent 434,875
And the dihydroperimidine squarylium dye described in U.S. Pat. No. 5,380,635.

Further, Epollight III-178,
Epollight III-130, Epollight I
II-125, Epolight IV-62A and the like are particularly preferably used. Another particularly preferred example of the dye is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993.

These dyes or pigments may be added to the positive photosensitive composition of the present invention and added to the photosensitive layer together with other components. And another layer may be added and added thereto.
These dyes or pigments may be used alone or in combination of two or more.

[Alkali-soluble polymer]
Said alkali-soluble polymer is the main polymer compound
Those having the following acid group structure in the chain or side chain
You. Phenolic hydroxyl group (-Ar-OH), carboxylic acid
Group (-CO_ThreeH), sulfonic acid group (-SO_ThreeH), phosphorus
Acid group (-OPO_ThreeH), a sulfonamide group (—SO _TwoN
HR), substituted sulfonamide-based acid groups (active imide groups)
(-SO_TwoNHCOR, -SO_TwoNHSO_TwoR, -CO
NHSO_TwoR). Here, even if Ar has a substituent,
Represents a good divalent aryl group, wherein R has a substituent
Represents a good hydrocarbon group. Among them, preferred acid groups
(B-1) phenolic hydroxyl group, (b-2) sulfo
And an (b-3) active imide group.
(B-1) A polymer compound having a phenolic hydroxyl group
Is preferably used.

(B-1) Examples of the high molecular compound having a phenolic hydroxyl group include a condensation polymer of phenol and formaldehyde (hereinafter, referred to as "phenol formaldehyde resin") and a degeneration of m-cresol and formaldehyde. (Hereinafter referred to as "m-cresol formaldehyde resin"), a condensation polymer of p-cresol and formaldehyde, a condensation polymer of m- / p-mixed cresol and formaldehyde, phenol and cresol (m-, p- , Or m- / p-mixture)
Novolak resins such as polycondensates of formaldehyde and
And a condensation polymer of pyrogallol and acetone. Alternatively, a copolymer obtained by copolymerizing a monomer having a phenol group in a side chain can be used.
Examples of the monomer having a phenol group include acrylamide, methacrylamide, acrylate, methacrylate, and hydroxystyrene having a phenol group. Specifically, N- (2-
(Hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (2-hydroxyphenyl) methacrylamide, N- (3-hydroxyphenyl) methacrylamide, N- ( 4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate, m-hydroxyphenyl methacrylate, p-hydroxyphenyl methacrylate, o-hydroxystyrene, m -Hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) ethyl acrylate, - (4-hydroxyphenyl) ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate, 2- (4-hydroxyphenyl)
Ethyl methacrylate and the like can be suitably used. The weight average molecular weight of the polymer is 5.0 × 10 ^{2 to} 2.0
× 10 ⁴ , number average molecular weight 2.0 × 10 ^{2 to} 1.0 × 1
0 ⁴ ones are preferred in view of image forming properties. These resins may be used alone or in combination of two or more. When they are combined, they have 3 to 8 carbon atoms, such as a condensation polymer of t-butylphenol and formaldehyde or a condensation polymer of octylphenol and formaldehyde as described in U.S. Pat. No. 4,123,279. A condensation polymer of phenol and formaldehyde having an alkyl group as a substituent may be used in combination.

The high molecular compound having a phenolic hydroxyl group preferably has a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 10,000. Further, as described in U.S. Pat. No. 4,123,279, a condensate of phenol having a C3-8 alkyl group as a substituent and formaldehyde, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin. May be used in combination. These polymer compounds having a phenolic hydroxyl group may be used alone or in combination of two or more.

(B-2) The polymer compound having a sulfonamide group contains a monomer having a sulfonamide group as a main constituent. Examples of the monomer having a sulfonamide group include a monomer comprising a sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom in one molecule and a low-molecular compound having at least one polymerizable unsaturated bond. Is mentioned. Among them, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group is preferable. Examples of such compounds include compounds represented by the following general formulas (1) to (5).

[0077]

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Where X¹And X^TwoAre independently-
O- or -NR²⁷Represents-. R^{twenty one}And R^{twenty four}Respectively
Independently a hydrogen atom or -CH_ThreeRepresents R^{twenty two}, R^{twenty five},
R²⁹, R ³²And R³⁶Are each independently having a substituent
An alkylene group having 1 to 12 carbon atoms which may be
Represents a kylene group, an arylene group or an aralkylene group. R
^{twenty three}, R²⁷And R³³Are each independently a hydrogen atom, a substituent
An alkyl group having 1 to 12 carbon atoms which may have
Represents a loalkyl group, an aryl group or an aralkyl group. Ma
R²⁶And R³⁷Each independently has a substituent
An alkyl group having 1 to 12 carbon atoms, cycloalkyl
Represents an aryl group or an aralkyl group. R²⁸, R³⁰
And R³⁴Are each independently a hydrogen atom or -CH_ThreeThe table
You. R³¹And R³⁵Is independently a single bond or substituted
An alkylene group having 1 to 12 carbon atoms which may have a group,
Cycloalkylene group, arylene group or aralkylene group
Represents Y^ThreeAnd Y^FourAre each independently a single bond, or
Represents -CO-.

Specifically, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

(B-3) The polymer compound having an active imide group has an active imide group represented by the following formula in the molecule, and is a main monomer constituting the polymer compound. As the monomer having a group,
In one molecule, a monomer composed of a low molecular compound having at least one active imide group represented by the following formula and at least one polymerizable unsaturated bond is exemplified.

[0081]

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As such a compound, specifically,
N- (p-toluenesulfonyl) methacrylamide, N
-(P-Toluenesulfonyl) acrylamide and the like can be suitably used.

The alkali-soluble polymer used in the present invention is
It is not necessary to consist of one kind selected from monomers having an acidic group of (b-1) to (b-3), and two or more kinds of monomers having the same acidic group or monomers having different acidic groups may be used. Those obtained by copolymerizing two or more kinds can also be used. As a copolymerization method, a conventionally known graft copolymerization method, block copolymerization method, random copolymerization method, or the like can be used.

The copolymer is copolymerized (b-1)
It is preferable that the monomer having the acidic group of (b-3) is contained as a copolymer component in an amount of 10 mol% or more, more preferably 20 mol% or more. (B-1)
If the amount of the monomer (b-3) containing an acidic group is less than 10 mol%, the effect of improving the development latitude will be insufficient.

The copolymer (b-1)
A monomer other than the monomer having an acidic group of (b-3) may be contained as a copolymerization component. Examples of other monomers that can be used as a copolymer component include:
The following monomers (1) to (12) are exemplified.

(1) Acrylic esters having an aliphatic hydroxyl group, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, and methacrylic esters. (2) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl Alkyl acrylates such as acrylates; (3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl Alkyl methacrylates such as methacrylate. (4) acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-
Hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-
Acrylamide or methacrylamide such as phenylacrylamide, N-nitrophenylacrylamide, and N-ethyl-N-phenylacrylamide. (5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether. (6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate. (7) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene. (8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone. (9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene. (10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like. (11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, and N- (p-chlorobenzoyl) methacrylamide. (12) acrylic acid, methacrylic acid, maleic anhydride,
Unsaturated carboxylic acids such as itaconic acid;

In the present invention, as the alkali-soluble polymer, those having a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more are preferable irrespective of a homopolymer or a copolymer in view of film strength. More preferably, the weight average molecular weight is 5,000 to 300,000, and the number average molecular weight is 800
２５０250,000 and a degree of dispersion (weight average molecular weight / number average molecular weight) of 1.1 to 10.

In the above copolymer, (b-1) to (b)
The compounding weight ratio of the monomer having an acidic group of (3) to another monomer is preferably in the range of 50:50 to 5:95 from the viewpoint of development latitude, and is preferably in the range of 40:60 to 10:90. Are more preferable.

Examples of the alkali-soluble polymer used in the present invention include those having a phenol structure having at least one electron-withdrawing substituent on an aromatic ring described in Japanese Patent Application No. 11-47019. When such an alkali-soluble polymer is used in combination with the infrared absorbent represented by the general formula (1), it is particularly preferable in view of stability over time. This is presumed to be due to a strong hydrogen bond-like interaction between the chalcogen atom of the infrared absorber and the phenolic hydroxyl group. When such a phenolic hydroxyl group having an electron-withdrawing substituent on the aromatic ring is present in an amount of about 1 mol% of the alkali-soluble polymer, the effect of stabilizing with time is exhibited.

Each of these alkali-soluble polymers may be used alone or in combination of two or more kinds. %, Particularly preferably 50%
It is used in an amount of up to 90% by weight. If the amount of the alkali-soluble polymer is less than 30% by weight, the durability of the photosensitive layer deteriorates, and if it exceeds 99% by weight, both sensitivity and durability are not preferred.

[Other Components] The infrared absorbent of the present invention can be combined with a polyfunctional water-soluble amine described in Japanese Patent Application No. 11-36074 as an additive. The use of such an amine compound is preferred in terms of stability over time. The amine compound interacts with the alkali-soluble group of the alkali-soluble polymer, but further interacts with the chalcogen atom of the infrared absorbent according to the present invention, so that a stronger interaction occurs and further stabilization over time occurs. Is considered to be expressed.

Various additives can be further added to the positive photosensitive composition of the present invention, if necessary. For example, the use of a substance which is thermally decomposable, such as an aromatic sulfone compound or an aromatic sulfonic acid ester compound, and substantially reduces the solubility of an alkali-soluble polymer in a state where it is not decomposed can be used in combination with a developer for an image area. It is preferable from the viewpoint of improving the dissolution-inhibiting property of the compound.

For the purpose of further improving the sensitivity, cyclic acid anhydrides, phenols and organic acids can be used in combination. As the cyclic acid anhydride, US Pat.
Phthalic anhydride described in US Pat. No. 15,128;
Tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ ⁴ -tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride,
Chloromaleic anhydride, α-phenylmaleic anhydride,
Succinic anhydride, pyromellitic anhydride and the like can be used. Examples of the phenols include bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4 '
-Trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 "-trihydroxytriphenylmethane, 4,4', 3", 4 "-tetrahydroxy-3,
5,3 ', 5'-tetramethyltriphenylmethane and the like.

Further, examples of the organic acids include those described in
And sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphoric esters, carboxylic acids and the like described in JP-A-88942, JP-A-2-96755 and the like. Sulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,
4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4
-Cyclohexene-1,2-dicarboxylic acid, erucic acid,
Lauric acid, n-undecanoic acid, ascorbic acid and the like can be mentioned. The proportion of the above cyclic acid anhydride, phenols and organic acids in the positive photosensitive composition is 0.05%.
-20% by weight is preferred, 0.1-15% by weight is more preferred, and 0.1-10% by weight is particularly preferred.

Further, in the positive photosensitive composition of the present invention, JP-A-62-251740 and JP-A-3-208514 are used in order to widen the stability of processing under development conditions.
Non-ionic surfactants described in JP-A-59-121044, JP-A-4-13149.
An amphoteric surfactant such as that described in JP-A No. 2-211 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, stearic acid monoglyceride, and polyoxyethylene nonyl phenyl ether. Specific examples of the amphoteric surfactant include alkyl di (aminoethyl) glycine, alkyl polyaminoethyl glycine hydrochloride, 2-alkyl-N-
Carboxyethyl-N-hydroxyethylimidazolinium betaine or N-tetradecyl-N, N-betaine type (for example, trade name "Amogen K": Daiichi Kogyo Co., Ltd.)
Manufactured). The proportion of the nonionic surfactant and the amphoteric surfactant in the positive photosensitive composition,
It is preferably from 0.05 to 15% by weight, more preferably from 0.1 to 5% by weight.

In the positive photosensitive composition of the present invention, a printing-out agent for obtaining a visible image immediately after heating by exposure,
Dyes and pigments as image colorants can be added.
Representative examples of the printing-out agent include a combination of a compound that releases an acid upon exposure to light (photoacid releasing agent) and an organic dye that can form a salt. Specifically, o-naphthoquinonediazide-4 described in JP-A-50-36209 and JP-A-53-8128 is disclosed.
A combination of a sulfonic acid halide and a salt-forming organic dye, and JP-A-53-36223 and JP-A-54-74728.
And combinations of trihalomethyl compounds and salt-forming organic dyes described in JP-A Nos. 60-3626, 61-143748, 61-151644 and 63-58440. The trihalomethyl compound includes an oxazole-based compound and a triazine-based compound, both of which have excellent stability over time and give clear print-out images.

As the colorant for the image, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Suitable dyes, including salt-forming organic dyes, include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS,
Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (all manufactured by Orient Chemical Industries, Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201)
5) and the like. Also, Japanese Patent Application Laid-Open No. 62-293247
The dyes described in the publication are particularly preferred. These dyes are used in an amount of 0.0% based on the total solid content of the positive photosensitive composition.
It can be added to the positive photosensitive composition at a ratio of 1 to 10% by weight, preferably 0.1 to 3% by weight.

Further, a plasticizer is added to the positive photosensitive composition of the present invention, if necessary, in order to impart flexibility to the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate,
For example, oligomers and polymers of trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid are used.

Further, in addition to these, epoxy compounds,
Vinyl ethers, phenol compounds having a hydroxymethyl group and phenol compounds having an alkoxymethyl group described in JP-A-8-276558 and Japanese Patent Application No. 9-328937 previously proposed by the present inventors. A crosslinkable compound having an alkali dissolution inhibiting action described above can be appropriately added according to the purpose.

The positive photosensitive composition of the present invention having the above constitution can be suitably used for a lithographic printing plate precursor. Hereinafter, a lithographic printing plate precursor using the positive photosensitive composition of the present invention will be described. In this specification, a lithographic printing plate precursor refers to a plate material in which an image forming pattern of an ink receiving portion and a non-ink receiving portion is not formed, and a lithographic printing plate is a non-ink receiving portion and a non-ink receiving portion. FIG. 4 shows a plate material in a state where an image pattern of an ink receiving portion is formed and is ready for printing.

The lithographic printing plate precursor has, on a support, a photosensitive layer containing the positive photosensitive composition of the present invention, and further, if necessary, other layers. The photosensitive layer can be usually produced by dissolving each of the above components in a solvent and coating the solution on a suitable support.
As the solvent used here, ethylene dichloride,
Cyclohexanone, methyl ethyl ketone, methanol,
Ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-
Methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, Examples include, but are not limited to, γ-butyrolactone, toluene, water, and the like. These solvents are used alone or as a mixture. The concentration of the above components (total solids including additives) in the solvent is preferably 1 to 50% by weight. The amount of coating (solid content) on the support obtained after coating and drying varies depending on the application, but generally speaking, the photosensitive printing plate is preferably 0.5 to 5.0 g / m ² . Various methods can be used as the method of coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. As the coating amount decreases, the apparent sensitivity increases,
The film properties of the photosensitive layer deteriorate.

In the photosensitive layer coating solution using the positive photosensitive composition of the present invention, a surfactant for improving coating properties,
For example, a fluorinated surfactant as described in JP-A-62-170950 can be added. A preferable addition amount is 0.0 to the total solid content of the photosensitive layer.
1 to 1% by weight, more preferably 0.05 to 0.5% by weight
It is.

The support used for the lithographic printing plate precursor is a dimensionally stable plate-like material, for example, paper,
Plastic (eg, polyethylene, polypropylene, polystyrene, etc.) laminated paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, Cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), metal-laminated or vapor-deposited paper as described above,
Alternatively, a plastic film or the like can be used.

As the support, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate having good dimensional stability and relatively low cost is particularly preferable. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a trace amount of a different element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like. The content of foreign elements in the alloy is at most 10% by weight
It is as follows. Particularly preferred aluminum is pure aluminum, but completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the composition of the aluminum plate is not specified, and an aluminum plate of a conventionally known and used material can be appropriately used. The thickness of the aluminum plate is about 0.1 to 0.6 mm, preferably 0.15 to 0.4 mm, and particularly preferably 0.2 to 0.6 mm.
0.3 mm.

Prior to roughening the aluminum plate, if necessary, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution is performed to remove rolling oil on the surface. The surface roughening treatment of the aluminum plate is performed by various methods, for example, a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically. It is performed by the method of causing. Known mechanical methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used as the mechanical method. Further, as an electrochemical surface roughening method, there is a method of performing an alternating or direct current in a hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can be used.
The aluminum plate thus surface-roughened is subjected to an alkali etching treatment and a neutralization treatment as required, and then subjected to an anodic oxidation treatment, if desired, in order to increase the water retention and abrasion resistance of the surface. As the electrolyte used for the anodic oxidation treatment of the aluminum plate, various electrolytes for forming a porous oxide film can be used, and generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte.

The anodizing treatment conditions vary depending on the electrolyte to be used, and thus cannot be specified unconditionally.
Current density 5 to 60 A / dm ^2, voltage 1 to 100 V, which is an electrolyzing time of 10 seconds to 5 minutes. When the amount of the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient or the non-image area of the lithographic printing plate is easily scratched, and the ink adheres to the scratched area during printing. So-called “scratch dirt” easily occurs. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment as necessary. Examples of the hydrophilic treatment used in the present invention include U.S. Pat. Nos. 2,714,066 and 3,181,461.
There is an alkali metal silicate (for example, sodium silicate aqueous solution) method as disclosed in 3,280,734 and 3,902,734. In this method, the support is immersed in an aqueous solution of sodium silicate or electrolytically treated. Other Japanese Patent Publication No. 36-22063
Potassium fluoride zirconate and U.S. Pat. Nos. 3,276,868 and 4,153,4.
No. 61, 4,689,272, a method of treating with polyvinyl phosphonic acid or the like is used.

The lithographic printing plate precursor is provided with a positive photosensitive layer containing the positive photosensitive composition of the present invention on a support. If necessary, an undercoat layer Can be provided. As the undercoat layer component, various organic compounds are used, for example, carboxymethylcellulose, dextrin, gum arabic, phosphonic acids having an amino group such as 2-aminoethylphosphonic acid, and phenylphosphone which may have a substituent. Organic phosphonic acids such as acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid and alkylglyceric acid which may have a substituent Organic phosphoric acid such as, phenylphosphinic acid which may have a substituent,
Organic phosphinic acids such as naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, glycine and β
-Selected from amino acids such as alanine, and hydrochlorides of amines having a hydroxy group such as triethanolamine hydrochloride, but may be used in combination of two or more.

The organic undercoat layer can be provided by the following method. That is, a method in which a solution obtained by dissolving the above organic compound in water or an organic solvent such as methanol, ethanol, and methyl ethyl ketone or a mixed solvent thereof is coated on an aluminum plate and dried, and a method in which water or methanol, ethanol, methyl ethyl ketone, or the like is provided. A method in which an aluminum plate is immersed in a solution in which the above organic compound is dissolved in an organic solvent or a mixed solvent thereof to adsorb the above compound, followed by washing with water or the like and drying to form an organic undercoat layer. It is. In the former method, a solution of the above organic compound having a concentration of 0.005 to 10% by weight can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by weight, preferably 0.05 to 5% by weight.
The immersion temperature is 20 to 90 ° C., preferably 25 to 5 ° C.
0 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this is ammonia,
Basic substances such as triethylamine and potassium hydroxide,
The pH can be adjusted to a range of 1 to 12 with an acidic substance such as hydrochloric acid or phosphoric acid. Further, a yellow dye can be added for improving the tone reproducibility of the image recording material. The coverage of the organic undercoat layer, 2 to 200 mg / m ² are suitable, and preferably from 5 to 100 mg / m ^2. If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. The same is true even if it is larger than 200 mg / m ² . As described above, a lithographic printing plate precursor using the positive photosensitive composition of the present invention can be produced.

Hereinafter, the exposure and development processes will be described.
The positive type lithographic printing plate precursor prepared as described above is usually subjected to image exposure and development processing. As the light source of the actinic ray used for image exposure, for example, a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp,
There are carbon arc lamps and the like. As radiation, electron beam,
X-rays, ion beams, far infrared rays, and the like. G line, i
Lines, Deep-UV light, high density energy beams (laser beams) are also used. Examples of the laser beam include a helium-neon laser, an argon laser, a krypton laser, a helium-cadmium laser, an excimer laser, a solid-state laser, and a semiconductor laser. In the present invention, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid-state laser and a semiconductor laser are particularly preferable.

As the developer and replenisher for the lithographic printing plate precursor, conventionally known aqueous alkali solutions can be used. For example, sodium silicate, potassium silicate,
Sodium triphosphate, potassium phosphate tribasic, ammonium phosphate tribasic, sodium phosphate dibasic, potassium phosphate dibasic, ammonium phosphate dibasic, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate,
Examples thereof include inorganic alkali salts such as potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, ammonium borate, sodium hydroxide, ammonium hydroxide, potassium hydroxide, and lithium hydroxide. Also, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used.

These alkali agents are used alone or in combination of two or more. Among these alkali agents, particularly preferred developers are aqueous silicate solutions such as sodium silicate and potassium silicate. The reason is that the developability can be adjusted by the ratio and the concentration of the silicon oxide SiO ₂ and the alkali metal oxide M ₂ O which are the components of the silicate. For example, JP-A-54-62004 discloses The alkali metal silicate described in JP-B-57-7427 is effectively used.

In the case of developing using an automatic developing machine, an aqueous solution having a higher alkali strength than the developing solution (replenisher)
It has been known that a large amount of PS plates can be processed without replacing the developing solution in the developing tank for a long time by adding to the developing solution. This replenishment system is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developing solution and the replenishing solution as needed for the purpose of promoting or suppressing the developing property, dispersing the developing residue and increasing the ink affinity of the printing plate image area. Preferred surfactants include
Examples include anionic, cationic, nonionic and amphoteric surfactants. Further, the developing solution and the replenisher, if necessary, hydroquinone, resorcinol, sulfurous acid, sodium salts of inorganic acids such as bisulfite, reducing agents such as potassium salts,
Further, an organic carboxylic acid, an antifoaming agent and a water softener can be added. The printing plate developed using the developer and the replenisher is rinse water containing a washing water, a surfactant, etc.,
It is post-treated with a desensitizing solution containing gum arabic and a starch derivative. As the post-processing when the positive photosensitive composition of the present invention is used as a printing plate, these processings can be used in various combinations.

In recent years, in the plate making / printing industry, automatic developing machines for printing plates have been widely used in order to rationalize and standardize plate making operations. This automatic developing machine generally includes a developing section and a post-processing section, and includes a device for transporting a printing plate, each processing solution tank and a spray device, and transports the exposed printing plate horizontally while pumping each plate. The developing process is performed by spraying a processing liquid from a spray nozzle. Recently, a method is also known in which a printing plate is immersed and conveyed by a submerged guide roll or the like in a processing liquid tank filled with a processing liquid to perform processing. In such an automatic processing, the processing can be performed while replenishing each processing liquid with a replenisher according to the processing amount, the operating time, and the like. Further, a so-called disposable processing method in which processing is performed with a substantially unused processing liquid can also be applied.

When the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming has an unnecessary image portion (for example, a film edge mark of an original film), The unnecessary image portion is erased. Such erasure is performed, for example, in Japanese Patent Publication No. 2-1329.
Japanese Patent Application Laid-Open No. 59-174 discloses a method in which an erasing liquid as described in JP-A No. 3 is applied to an unnecessary image portion, left as it is for a predetermined time, and then washed with water.
No. 842, a method of irradiating an unnecessary image portion with an actinic ray guided by an optical fiber and then developing the unnecessary image portion can also be used.

The planographic printing plate obtained as described above is
After applying the desensitized gum as desired, it can be subjected to a printing process. However, when a lithographic printing plate having a higher printing durability is desired, a burning treatment is performed. In the case where the lithographic printing plate is subjected to a burning treatment, prior to the burning treatment, JP-B Nos. 61-2518 and 55-28062,
It is preferable to treat with a surface-regulating liquid as described in JP-A-62-31859 and JP-A-61-159655. As a method, a sponge or absorbent cotton impregnated with a surface-regulating liquid is applied on a lithographic printing plate, or a printing plate is immersed in a vat filled with the surface-regulating liquid, or is applied automatically. Coating by a coater or the like is applied. Also, after applying, with a squeegee or squeegee roller,
Making the coating amount uniform gives more preferable results. The application amount of the surface conditioning liquid is generally 0.03 to 0.8 g /
m ² (dry weight) is appropriate.

The lithographic printing plate to which the surface conditioning liquid has been applied is dried if necessary, and then burned (for example, a burning processor sold by Fuji Photo Film Co., Ltd .: "BP-1300") or the like. Is heated to a high temperature. The heating temperature and time in this case depend on the type of the component forming the image, but are preferably in the range of 180 to 300 ° C. and 1 to 20 minutes.

The burned lithographic printing plate can be subjected to conventional treatments such as washing with water and gumming, if necessary. When a liquid is used, so-called desensitizing treatment such as gumming can be omitted. The lithographic printing plate obtained by such a process is applied to an offset printing machine or the like and used for printing a large number of sheets.

[0118]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. (Example 1) [Preparation of substrate] An aluminum plate (material 1050) having a thickness of 0.3 mm was washed with trichlorethylene and degreased, and then a nylon brush and a 400 mesh pumice-water suspension were used. Grained and washed well with water.
This aluminum plate was etched by immersing it in a 25% aqueous solution of sodium hydroxide at 45 ° C. for 9 seconds, washed with water, further immersed in 20% nitric acid for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² . Next, a 3 g / m ² direct current anodic oxide film was formed on the aluminum plate at a current density of 15 A / dm ² using 7% sulfuric acid as an electrolytic solution, followed by washing with water and drying.
The coating was dried at 90 ° C. for 1 minute. The coating amount of the dried coating film was 10 mg / m ² .

—Composition of Undercoating Solution— β-alanine 0.5 g Methanol 95 g Water・ ・ ・ ・ ・ ・ ・ ・ 5g

[Preparation of Lithographic Printing Plate Precursor] A photosensitive solution 1 having the following composition was prepared and applied onto the above-mentioned substrate as a support so that the coating amount was 1.8 g / m ^2. A lithographic printing plate precursor was prepared.

—Composition of Photosensitive Solution 1— m, p-cresol novolak 1.0 g (m / p ratio = 6/4, weight average molecular weight 3500, unreacted) Cresol 0.5% by weight) Infrared absorbers listed in Table 1 below: 0.2 g The counter anion of Victoria Pure Blue BOH is converted to 1-naphthalenesulfonic acid anion. 0.02 g Fluorosurfactant 0 .05 g (MegaFac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) γ-butyrolactone 3 g methyl ethyl ketone ... 8 g 1-methoxy-2-propanol ·············· 7g

(Examples 2 to 5) The procedure of Example 1 was repeated, except that the infrared absorbing agent used in the preparation of the photosensitive solution 1 was replaced with the infrared absorbing agent shown in Table 1. The lithographic printing plate precursors of Examples 2 to 5 were produced.

Comparative Examples 1 and 2 In Example 1, the infrared absorbing agent used in the preparation of the photosensitive solution 1 was replaced by infrared absorbing agents B-1 and B-2 represented by the following structural formulas. In the same manner as in Example 1, lithographic printing plate precursors of Comparative Examples 1 and 2 were produced.

[0124]

Embedded image

Example 6 [Synthesis of Copolymer 1 as Alkali-Soluble Polymer] In a 500 ml three-necked flask equipped with a stirrer, a condenser, and a dropping funnel, 31.0 g (0.36 mol) of methacrylic acid, chloroformate 39.1 g (0.36 mol) of ethyl and 200 ml of acetonitrile were added, and the mixture was stirred while cooling in an ice-water bath. To this mixture was added triethylamine 36.4.
g (0.36 mol) was added dropwise using a dropping funnel over about 1 hour. After dropping, remove the ice-water bath and allow
The mixture was stirred for 0 minutes.

To the reaction mixture was added 51.7 g (0.30 mol) of p-aminobenzenesulfonamide, and the mixture was stirred for 1 hour while warming to 70 ° C. in an oil bath. After the completion of the reaction, this mixture was charged while stirring 1 liter of water, and the resulting mixture was stirred for 30 minutes. The mixture was filtered to remove a precipitate, which was slurried with 500 ml of water. The slurry was filtered, and the obtained solid was dried to obtain a white solid of N- (p-aminosulfonylphenyl) methacrylamide. Was obtained (yield 4).
6.9 g).

Next, the obtained N- (p-) was added to a 100 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel.
Aminosulfonylphenyl) methacrylamide 5.04
g (0.0210 mol), ethyl methacrylate 2.05
g (0.0180 mol), acrylonitrile 1.11 g
(0.021 mol) and 20 g of N, N-dimethylacetamide were added, and the mixture was stirred while being heated to 65 ° C. in a hot water bath. 0.15 g of "V-65" (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the mixture, and the mixture was stirred for 2 hours under a nitrogen stream while maintaining the temperature at 65 ° C. To the reaction mixture was further added 5.04 g of N- (p-aminosulfonylphenyl) methacrylamide, 2.05 g of ethyl methacrylate, 1.11 g of acrylonitrile, 20 g of N, N-dimethylacetamide and 0.15 g of “V-65”. The mixture was added dropwise over 2 hours using a dropping funnel. After dropping, 6 more
The resulting mixture was stirred at 5 ° C. for 2 hours. After the reaction,
40 g of methanol was added to the mixture, and the mixture was cooled, and the obtained mixture was added while stirring 2 liters of water. After stirring the mixture for 30 minutes, the precipitate was taken out by filtration and dried to obtain 15 g of a white solid. Was. The weight average molecular weight of this copolymer 1 (polystyrene standard) was measured by gel permeation chromatography and found to be 53,000.

[Preparation of lithographic printing plate precursor] In Example 1, except that the photosensitive solution 1 was replaced by the photosensitive solution 2 having the following composition,
In the same manner as in Example 1, the lithographic printing plate precursor of Example 6 was produced.

—Composition of Photosensitive Liquid 2— Copolymer 1 1.0 g Infrared absorbents listed in Table 2 below 0.1 g of a dye in which the counter anion of Victoria Pure Blue BOH is converted to 1-naphthalenesulfonic acid anion ... 0.02 g Fluorinated surfactant 0.05 g (MegaFac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) γ-butyrolactone 8 g methyl ethyl ketone 8 g 1- Methoxy-2-propanol 4g

(Examples 7 to 10) In the same manner as in Example 6, except that the infrared absorbing agent used in the preparation of the photosensitive solution 2 was changed to the infrared absorbing agent shown in Table 2 above, The lithographic printing plate precursors of Examples 7 to 10 were produced.

(Comparative Examples 3 and 4) In Example 6, the infrared absorbent used for preparing the photosensitive solution 2 was changed to the infrared absorbents B-1 and B-2 represented by the above structural formulas. In the same manner as in Example 6, lithographic printing plate precursors of Comparative Examples 3 and 4 were produced.

Example 11 Synthesis of Copolymer 2 as Alkali-Soluble Polymer In a 100 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel, N- (p- 4.61 g of aminosulfonylphenyl) methacrylamide
(0.0192 mol), 2.94 g of ethyl methacrylate
(0.0258 mol), 0.80 g of acrylonitrile
(0.015 mol) and 20 g of N, N-dimethylacetamide, and the mixture was stirred while being heated to 65 ° C. in a hot water bath. 0.15 g of "V-65" (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the mixture, and the mixture was stirred for 2 hours under a nitrogen stream while maintaining the temperature at 65 ° C. To this reaction mixture was further added a mixture of 4.61 g of N- (p-aminosulfonylphenyl) methacrylamide, 2.94 g of ethyl methacrylate, 0.80 g of acrylonitrile, 0.15 g of N, N-dimethylacetamide and "V-65". Was dropped by a dropping funnel over 2 hours. After the completion of dropping, further add
The resulting mixture was stirred for hours. After the completion of the reaction, 40 g of methanol was added to the mixture, and the mixture was cooled, and the obtained mixture was added with stirring 2 liters of water. The mixture was stirred for 30 minutes, and the precipitate was taken out by filtration and dried to obtain 15 g of white A solid was obtained. The weight average molecular weight (polystyrene standard) of the copolymer 2 was measured by gel permeation chromatography and found to be 53,000.
Met.

[Preparation of lithographic printing plate precursor] In Example 1, except that the photosensitive solution 1 was replaced by the photosensitive solution 3 having the following composition,
In the same manner as in Example 1, the lithographic printing plate precursor of Example 11 was produced.

—Composition of Photosensitive Liquid 3— Copolymer 2 0.75 gm, p-cresol novolak 0.25 g (m: p ratio = 6: 4, weight average molecular weight 3,500, unreacted cresol 0.5% by weight) Tetrahydrophthalic anhydride 0.03 g Infrared absorbents listed in Table 3 below 0.017 g The counter anion of Victoria Pure Blue BOH was changed to 1-naphthalenesulfonic acid anion Dye ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.015g Fluorine surfactant ・ ・ ・ ・ ・ ・ ・ 0.05g (MegaFac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) γ-butyrolactone 10 g methyl ethyl ketone 10 g 1-methoxy-2-propanol・ ・ ・ ・ ・ ・ ・ ・ ・ 1g

Examples 12 to 19 The procedure of Example 11 was repeated, except that the infrared absorbing agent used for preparing the photosensitive solution 3 was replaced with the infrared absorbing agent shown in Table 3. The lithographic printing plate precursors of Examples 12 to 19 were produced.

(Comparative Examples 5 and 6) The procedure of Example 11 was repeated except that the infrared absorbent used for preparing the photosensitive solution 3 was replaced with the infrared absorbents B-1 and B-2 represented by the above structural formulas. In the same manner as in Example 11, lithographic printing plate precursors of Comparative Examples 5 and 6 were produced.

(Example 20) [Synthesis of alkali-soluble polymer A] m, p-cresol novolak (m: p ratio = 6: 4, weight average molecular weight 3,5)
12 parts by weight of the unreacted cresol (0.5% by weight) were dissolved in 100 parts by weight of tetrahydrofuran and stirred at room temperature, and 4 parts by weight of sulfuryl chloride (SO ₂ Cl ₂ ) was slowly dropped into this solution. After the reaction solution was stirred at room temperature for 8 hours, it was poured into 1000 parts by weight of water, and the separated alkali-soluble polymer A was taken out and washed with water to give a chlorination rate of 30 mol% (relative to phenolic hydroxyl groups). 13 parts by weight of the alkali-soluble polymer A was obtained. still,
The pKa value of the phenolic hydroxyl group into which chlorine has been introduced as the electron-withdrawing substituent is 7 to 9.

[Preparation of Lithographic Printing Plate Precursor] In Example 1, except that the photosensitive solution 1 was replaced by the photosensitive solution 4 having the following composition,
A lithographic printing plate precursor of Example 20 was prepared in the same manner as in Example 1.

—Composition of Photosensitive Solution 4— The Alkali-Soluble Polymer A 1.10 g Infrared absorbents listed in Table 4 below 0.20 g Dye in which the counter anion of Victoria Pure Blue BOH is converted to 1-naphthalenesulfonic acid anion 0.02 g Fluorine Surfactant 0.05 g (MegaFac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) γ-butyrolactone 3.0 g methyl ethyl ketone 8.0 g 1-methoxy-2-propanol ···· 7.0 g

Examples 21 to 24 In the same manner as in Example 20, except that the infrared absorbing agent used for preparing the photosensitive solution 4 was replaced with the infrared absorbing agent shown in Table 4 in Example 20, The lithographic printing plate precursors of Examples 21 to 24 were produced.

(Comparative Examples 7 and 8) In Example 20, the infrared absorbent used in the preparation of the photosensitive solution 4 was changed to the infrared absorbents B-1 and B-2 represented by the above structural formulas. In the same manner as in Example 20, lithographic printing plate precursors of Comparative Examples 7 and 8 were produced.

(Example 25) [Preparation of lithographic printing plate precursor] The procedure of Example 25 was repeated, except that the photosensitive solution 1 was replaced by the photosensitive solution 5 having the following composition. A lithographic printing plate precursor was prepared.

—Composition of Photosensitive Solution 5— Multifunctional Amine Compound A represented by the following structural formula 0.10 gm, p-cresol novolak 1.0 g (m: p ratio = 6: 4, weight average molecular weight 3500, unreacted cresol 0.5% by weight) Infrared absorbents listed in Table 5 below .. 0.20 g Dye in which the counter anion of Victoria Pure Blue BOH is converted to 1-naphthalenesulfonic acid anion ... 0.02 g Fluorosurfactant 0.05 g (MegaFac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) γ-butyrolactone・ ・ ・ ・ ・ ・ ・ ・ ・ 3.0g Methyl ethyl ketone ・ ・ ・ ・ ・ ・ ・ ・ ・········ 8.0 g 1-methoxy-2-propanol ············ 7.0 g

[0144]

Embedded image

Examples 26 to 29 The procedure of Example 25 was repeated, except that the infrared absorbing agent used in the preparation of the photosensitive solution 5 was replaced with the infrared absorbing agent shown in Table 5. The lithographic printing plate precursors of Examples 26 to 29 were produced.

(Comparative Examples 9 and 10) In Example 25,
Comparative Examples 9 and 10 were prepared in the same manner as in Example 25, except that the infrared absorber used for preparing the photosensitive solution 5 was replaced with the infrared absorbers B-1 and B-2 represented by the structural formulas. A lithographic printing plate precursor was prepared.

<Evaluation of Sensitivity and Development Latitude> The lithographic printing plate precursors of Examples 1 to 29 and Comparative Examples 1 to 10 were
As shown in Tables 1 to 5 below, exposure was performed using a semiconductor laser having a wavelength of 840 nm or a YAG laser having a wavelength of 1064 nm. Which laser is used was appropriately selected according to the absorption wavelength of the infrared absorbing dye contained therein. After the exposure, an automatic developing machine (“PS”) charged with a developing solution DP-4 and a rinsing solution FR-3 (1: 7) manufactured by Fuji Photo Film Co., Ltd.
Processor 900VR ", Fuji Photo Film Co., Ltd.
Developed using the following method. The developer DP-4 was prepared in two levels, one diluted 1: 7 and one diluted 1:12. The line width of the non-image area obtained with the developer diluted 1: 7 of DP-4 was measured, the irradiation energy of the laser corresponding to the line width was determined, and the sensitivity index (mJ / c) was obtained.
m ² ). The smaller the measured value (mJ / cm ² ), the higher the sensitivity of the lithographic printing plate.

Next, the line width of the non-image area obtained by using the standard developer diluted 1: 7 and the diluted developer diluted 1:12 was measured, and the line width corresponding to the line width was measured. The irradiation energy of the laser to be used was determined, and the difference between the two sensitivities was used as an index of the development latitude. The smaller the difference is, the better the development latitude is, and if it is 20 mJ / cm ² or less, it is at a practical level.

<Evaluation of Storage Stability> The lithographic printing plate precursors of Examples 1 to 29 and Comparative Examples 1 to 10 were stored in an environment at a temperature of 60 ° C. for 3 days, and then subjected to laser irradiation in the same manner as described above. Exposure and development were performed, the sensitivity was determined in the same manner, the difference was compared with the above results, and the difference was determined as an index of storage stability. If the fluctuation of the sensitivity is 20 mJ / cm ² or less, the storage stability is good and is at a practical level. Tables 1 to 5 show the evaluation results.

[0150]

[Table 1]

[0151]

[Table 2]

[0152]

[Table 3]

[0153]

[Table 4]

[0154]

[Table 5]

From the above results, the lithographic printing plate precursors of Examples 1 to 29 have higher sensitivity to infrared lasers than the lithographic printing plate precursors of Comparative Examples 1 to 10, and the two levels of the developer It can be seen that the difference between the sensitivities when used was remarkably small, and that it had a sufficiently practical development latitude. Furthermore, in all of the lithographic printing plate precursors of Examples 1 to 29, the sensitivity fluctuations before and after storage were extremely small, the storage stability was excellent, and the lithographic printing plate precursors of Comparative Examples 1 to 10 were sufficiently practical. We are satisfied with the possible levels.

Further, in Examples 1 to 19, particularly, dyes having side chains in the methine chain (IR2-3, 8-1, 8-
2, 10-1, 10-6, 10-13, 11-5, 11
For -11), a tendency of high sensitivity was observed. This is considered to be because heat generated efficiently can be transferred to the alkali-soluble polymer because of good compatibility with the alkali-soluble polymer. The counter anion is ClO ₄ ⁻ , sulfonate,
Or, an organic anion such as a carboxylate was more sensitive. The reason is considered to be that ClO _4- ^{and the} like can generate heat by decomposition, and the organic anion is
This is considered to be due to the excellent compatibility with the alkali-soluble polymer.

Further, looking at Examples 20 to 24, when the infrared absorbent represented by the general formula (1) and an alkali-soluble polymer containing phenol having an electron-withdrawing group were used, particularly, It can be seen that the development latitude and the amount of change in energy after aging are small, and the fluctuation with time is small. Further, looking at Examples 25 to 29, when the infrared absorbent represented by the general formula (1) and the polyfunctional amine compound were used, particularly, the development latitude and the amount of energy change after aging were small, and It can be seen that the fluctuation is small.

[0158]

According to the present invention, it is possible to directly make a plate by recording from digital data of a computer or the like using a solid-state laser and a semiconductor laser that emit infrared light. In addition, a positive photosensitive composition having good development latitude and good storage stability can be provided.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Katsuya Chatani 4000F Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Pref. AA04 BA01 BA05 DA35 FA15 GA05

Claims (1)

[Claims] Claims: 1. An alkaline aqueous solution containing a polymer compound having an acidic group and an infrared absorbent represented by the following general formula (1) is suppressed before irradiation with infrared light. A positive photosensitive composition characterized by being soluble. Embedded image (In the general formula (1), X and Y are each an oxygen atom,
Represents a sulfur atom, a selenium atom, or a tellurium atom. M is
It represents a methine chain having 5 or more conjugated carbon atoms. Rx _{1 to} Rx ₄ and Ry _{1 to} Ry ₄ may be the same or different, and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group,
Represents an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. W ^- represents an anion. )