JP2005283680A - Image forming material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming material which has high sensitivity and large development latitude and suppressed deterioration in performance over time. <P>SOLUTION: The image forming material is obtained by disposing on a support a plurality of image recording layers containing a water-insoluble but alkali-soluble resin, wherein the top one of the plurality of image recording layers has an infrared absorbent represented by formula (I). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming material having an image recording layer whose solubility in an alkaline aqueous solution is changed by heat, and more specifically, so-called direct plate making which can be directly made by scanning infrared laser light based on a digital signal from a computer or the like. The present invention relates to an image forming material such as a positive type multi-layer sensitive material type lithographic printing plate precursor capable of making a plate.

With the development of image forming technology in recent years, it is possible to scan a plate with a narrowly focused laser beam and form a text document, an image document, etc. directly on the plate surface, and make a plate directly without using a film document. became.
However, in the so-called thermal positive type lithographic printing plate precursor that forms a positive image by causing photothermal conversion in the image recording layer by laser light irradiation to cause alkali solubilization of the image recording layer, as an image forming principle, There is a problem that the difference in the degree of on / off of alkali solubilization in the exposed / unexposed portion is reduced because the subtle interaction of the intermolecular interaction of the binder in the image recording layer due to laser exposure is utilized. .

  For this reason, for the purpose of obtaining an alkali-soluble discrimination in clear exposed / unexposed portions that can be used practically, a plurality of recording layers are laminated, and the uppermost layer is provided with surface insolubility in a developing solution, so that Means for suppressing the development solubility of the exposed portion is used (for example, see Patent Document 1).

  However, in such a lithographic printing plate precursor, there is room for improvement in the discrimination under various use conditions, and development stability (development latitude) depending on use conditions, in particular, solubility of the image recording layer over time (stability over time). ) Was desired.

Also, a method has been proposed in which an infrared absorber that can reduce the solubility of the entire recording layer in an alkaline developer is used, for example, in a recording layer having a single layer structure, instead of the recording layer having a multilayer structure as described above. (For example, refer to Patent Document 2). As a result, overdevelopment that has occurred when, for example, a high-concentration developer is used can be improved. There is still room for improvement in terms of stability.
JP 11-218914 A JP 2000-275828 A

  An object of the present invention is to provide an image forming material having high sensitivity, wide development latitude, and suppressing performance deterioration with time.

As a result of diligent research, the present inventor has found a condition under which the above object object can be achieved by adding an infrared absorber having a specific structure to the uppermost layer of the multilayer image recording layer.
In other words, specifically, the present invention
A plurality of image recording layers containing a water-insoluble and alkali-soluble resin are provided on a support, and an infrared absorber represented by the following general formula (I) is provided as the uppermost layer among the plurality of image recording layers. An image forming material characterized in that.

In general formula (I), R < ¹ > -R < ⁴ > shows a hydrogen atom, an alkyl group, or an aryl group each independently. R ⁵ and R ⁶ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represent an integer of 0 to 4. R ¹ and R ² , or R ³ and R ⁴ may be bonded to each other to form a ring, and R ¹ and / or R ² and R ⁵ , or R ³ and / or R ⁴ and R ^{6 May} be bonded to each other to form a ring, and when n or m is 2 or more, a plurality of R ⁵ or R ⁶ may be bonded to each other to form a ring. Z ¹ and Z ² each independently represent a hydrogen atom, an alkyl group or an aryl group. Q represents a trimethine group or a pentamethine group, which may have a ring structure formed with a divalent organic group. X ⁻ represents a counter anion.

Although the action of the present invention has not been clarified, by containing an infrared absorber having the structure of the above general formula (I) in the uppermost layer of the plurality of image recording layers, amides present at both ends thereof Due to the structure, solubility is increased in the exposed area and high sensitivity is promoted, and in the unexposed area, the dissolution inhibiting action on the alkaline developer is strengthened by the effect of suppressing the penetration of the developer, and the development latitude is widened. Further, it is presumed that deterioration of the development latitude over time is suppressed by particularly enhancing the dissolution inhibiting action of the surface portion (uppermost layer) of the image recording layer.

  According to the present invention, the exposed portion exhibits excellent developer solubility, the unexposed portion exhibits a penetration inhibitory action of the high-concentration developer, and the degradation of the penetration inhibitory action over time can be suppressed. That is, it is possible to obtain an image forming material with high sensitivity, wide development latitude, and suppressed performance deterioration with time.

In the image forming material of the present invention, a plurality of image recording layers containing a water-insoluble and alkali-soluble resin are provided on a support, and the uppermost layer (the layer farthest from the support. And simply referred to as the “uppermost layer”) having an infrared absorber represented by the following general formula (I).

In general formula (I), R < ¹ > -R < ⁴ > shows a hydrogen atom, an alkyl group, or an aryl group each independently. R ⁵ and R ⁶ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represent an integer of 0 to 4. R ¹ and R ² , or R ³ and R ⁴ may be bonded to each other to form a ring, and R ¹ and / or R ² and R ⁵ , or R ³ and / or R ⁴ and R ^{6 May} be bonded to each other to form a ring, and when n or m is 2 or more, a plurality of R ⁵ or R ⁶ may be bonded to each other to form a ring. Z ¹ and Z ² each independently represent a hydrogen atom, an alkyl group or an aryl group. Q represents a trimethine group or a pentamethine group, which may have a ring structure formed with a divalent organic group. X ⁻ represents a counter anion.

  The image recording layer has a multi-layer structure composed of a plurality of layers having different constituent components, and the uppermost layer contains a specific infrared absorber. For example, even if the lower layer portion other than the uppermost layer (the layer on the support side of the uppermost layer; hereinafter simply referred to as “lower layer”) is a single layer, there are two or more layers having different compositions and functions. It may be composed of layers. Here, a positive layer consisting of a two-layer structure comprising a lower layer containing an alkali-soluble resin and an upper layer containing an alkali-soluble resin and a specific infrared absorber (which is the uppermost layer in this configuration), which is a particularly preferred embodiment of the present invention. The image recording material of the mold will be described in detail as an example.

<Top layer>
First, the infrared absorbent which is an important requirement of the present invention will be described.
[Infrared absorber]
The image forming material of the present invention contains an infrared absorber represented by the following general formula (I) in the uppermost layer among a plurality of image recording layers containing a water-insoluble and alkali-soluble resin provided on a support. To do.
The infrared absorber refers to a substance that has a light absorption region in the infrared region of 700 nm or more, preferably 750 to 1200 nm, and exhibits light / heat conversion ability by light in the wavelength region of this range. Specifically, a dye having a structure of the following general formula (I) that absorbs light in the above wavelength range and generates heat can be used.

In general formula (I), R < ¹ > -R < ⁴ > shows a hydrogen atom, an alkyl group, or an aryl group each independently. R ⁵ and R ⁶ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represent an integer of 0 to 4. R ¹ and R ² , or R ³ and R ⁴ may be bonded to each other to form a ring, and R ¹ and / or R ² and R ⁵ , or R ³ and / or R ⁴ and R ^{6 May} be bonded to each other to form a ring, and when n or m is 2 or more, a plurality of R ⁵ or R ⁶ may be bonded to each other to form a ring. Z ¹ and Z ² each independently represent a hydrogen atom, an alkyl group or an aryl group. Q represents a trimethine group or a pentamethine group, which may have a ring structure formed with a divalent organic group. X ⁻ represents a counter anion.
Note that at least one of Z ¹ and Z ² is preferably a hydrogen atom or an alkyl group.

First, the substituent of the infrared absorber represented by the general formula (I) will be described. The present invention is not limited to these specific examples.
Examples of the alkyl group in R ^{1 to} R ⁴ , R ⁵ and R ⁶ , and Z ¹ and Z ² include linear, branched, or cyclic alkyl groups 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 group, s-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, A 2-norbornyl group can be mentioned. Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

These alkyl groups may have a substituent, and a monovalent nonmetallic atomic group excluding hydrogen is used as the substituent. 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-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group , Acylamino group, N-alkyl acyla 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 group, N′-aryl-N-arylureido group, N ′, N′- Diaryl-N-alkylureido group, N ′, N′-diaryl-N-arylureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl- -Arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, carboxyl group, and its conjugate base group, 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 (-S O ₃ H) and its conjugate base (hereinafter referred to as “sulfonate group”). ), Alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group , N- alkyl -N- arylsulfamoyl group, N- acylsulfamoyl group and a conjugate base group, N- alkylsulfonylsulfamoyl group (representing -SO ₂ NHSO ₂ R, R is an alkyl group.) and a conjugated base group, N- aryl sulfonylsulfamoyl group (-SO ₂ NHSO ₂ A , Ar represents an aryl group) and a conjugated base group, N- alkylsulfonylcarbamoyl group (-CONHSO ₂ R, R represents an alkyl group) and a conjugated base group, N- ants -.. Rusuru Honi carbamoyl group ( —CONHSO ₂ Ar, Ar represents an aryl group) and its conjugate base group, alkoxysilyl group (—Si (OR) ₃ , R represents an alkyl group), 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 its conjugate base group (hereinafter referred to as “phosphonate group”). ), dialkylphosphono group (-PO ₃ R ^2, R represents an alkyl group.), diarylphosphono group (-PO ₃ Ar _2, Ar represents an aryl group.), alkyl Riruhosuhono group _{(-PO 3 (R) (Ar} ), R is an alkyl group, Ar represents an aryl group.), Monoalkyl phosphono group _{(-PO 3 H (R),} R represents an alkyl group.) And Its conjugated base group (hereinafter referred to as “alkylphosphonate group”), monoarylphosphono group (—PO ₃ H (Ar), Ar represents an aryl group) and its conjugated base group (hereinafter referred to as “arylphosphonate”). Nato group ”), phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as“ phosphonatoxy group ”), dialkylphosphonooxy group (—OPO ₃ R ₂ , R represents an alkyl group) ), A diarylphosphonooxy group (—OPO ₃ Ar ₂ , Ar represents an aryl group). ), An alkylarylphosphonooxy group (—OPO ₃ (R) (Ar), R represents an alkyl group, Ar represents an aryl group), a monoalkylphosphonooxy group (—OPO ₃ H (R), R is Represents an alkyl group) and its conjugate base group, monoarylphosphonooxy group (—OPO ₃ H (Ar), Ar represents an aryl group) and its conjugate base group, cyano group, nitro group, aryl group ( For example, phenyl group, biphenyl group, naphthyl group, tolyl group, xylyl group, mesityl group, cumenyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group , Phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenyl Ophenyl group, methylaminophenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxycarbonylphenyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group, nitrophenyl group , Cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl group, phosphonatophenyl group, etc.), alkenyl group (for example, vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group) , 2-chloro-1-ethenyl group, etc.), alkynyl group (for example, ethynyl group, 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group, phenylethynyl group, etc.), acyl group. (R ⁷ C -; the R ^7, there may be mentioned hydrogen atom, also the R ¹ ~R ^4, R ⁵ and R ^6, and the alkyl group in Z ¹ and Z ^2, mentioned as the substituent for the alkyl group aryl Group, the same alkenyl group, the same alkynyl group, etc.).

In the above substituents, specific examples of the alkyl group represented by R include those similar to the alkyl groups in R ^{1 to} R ⁴ , R ⁵ and R ⁶ , and Z ¹ and Z ² . Specific examples of the aryl group represented by Ar include the same aryl groups listed as substituents for the alkyl group.

  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, N— Dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, formyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N An arylsulfamoyl group, -Alkyl-N-arylsulfamoyl group, phosphono group, phosphonato group, dialkylphosphono group, diarylphosphono group, monoalkylphosphono group, alkylphosphonato group, monoarylphosphono group, arylphosphonato group, phosphonooxy Groups, phosphonatoxy groups, aryl groups, alkenyl groups, acyl groups and the like.

  On the other hand, in the substituted alkyl group, as the alkylene group constituting the substituted alkyl group in combination with the substituent, any one of the aforementioned hydrogen atoms on the alkyl group having 1 to 20 carbon atoms is removed, and Examples include organic residues, preferably, linear alkylene groups having 1 to 12 carbon atoms, branched alkylene groups having 3 to 12 carbon atoms, and cyclic alkylene groups having 5 to 10 carbon atoms. it can. Preferred specific examples of the substituted alkyl group obtained by combining the substituent and the alkylene group include a chloromethyl group, a bromomethyl group, a 2-chloroethyl group, a trifluoromethyl group, a methoxymethyl group, a methoxyethoxyethyl group, and allyloxy. Methyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N-cyclohexylcarbamoyloxyethyl group, N-phenyl Carbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbonylethyl group, methoxycal Nylmethyl group, methoxycarbonylbutyl group, allyloxycarbonylbutyl group, chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylgalvamoylmethyl group, N- (methoxyphenyl) galvamoyl Ethyl group, N-methyl-N- (sulfophenyl) galvamoylmethyl group, sulfopropyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfa Moylpropyl group, N-tolylsulfamoylpropyl group, N-methyl-N- (phosphonophenyl) sulfyl octyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphos Nobutyl group, methylphosphonatobutyl group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonatoxybutyl 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, A 3-butynyl group etc. can be mentioned.

As the aryl group in R ^{1 to} R ⁴ , Z ¹ and Z ² , a benzene ring, two to three benzene rings forming a condensed ring, the benzene ring or condensed ring and a 5-membered unsaturated ring are condensed Specific examples include a ring group, and specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group. Among these, a phenyl group, a naphthyl group Groups are more preferred.

  As the substituted aryl group, those having a monovalent non-metallic atomic group excluding hydrogen as a substituent on the ring-forming carbon atom of the aforementioned aryl group are used. Preferred examples of the substituent include the alkyl groups, substituted alkyl groups, and substituents shown in the substituted alkyl group. Preferred examples of such a substituted aryl group include biphenyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, fluorophenyl group, chloromethylphenyl group, trifluoromethylphenyl group. , Hydroxyphenyl group, methoxyphenyl group, methoxyethoxyphenyl group, allyloxyphenyl group, phenoxyphenyl group, methylthiophenyl group, tolylthiophenyl group, phenylthiophenyl group, ethylaminophenyl group, dimethylaminophenyl group, diethylaminophenyl group Morpholinophenyl group, acetyloxyphenyl group, benzoyloxyphenyl group, N-cyclohexylcarbamoyloxyphenyl group, N-phenylcarbamoyloxyphenyl group, acetylaminophenol Group, N-methylbenzoylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, allyloxycarbonylphenyl group, chlorophenoxycarbonylphenyl group, galvamoylphenyl group, N-methylgalvamoylphenyl group, N, N-di Propylcarbamoylphenyl group, N- (methoxyphenyl) galvamoylphenyl group, N-methyl-N- (sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoylphenyl group, N-ethylsulfa Moylphenyl group, N, N-dipropylsulfamoylphenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phosphonophenyl group, phosphonatophenyl group Jie Ruphosphonophenyl group, diphenylphosphonophenyl group, methylphosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group, tolylphosphonatophenyl group, allylphenyl group, 1-propenylmethylphenyl group, 2-butyl Examples thereof include a tenenylphenyl group, a 2-methylallylphenyl group, a 2-methylpropenylphenyl group, a 2-propynylphenyl group, a 2-butynylphenyl group, and a 3-butynylphenyl group.

As the substituted oxy group for R ⁵ and R ^{6, those} in which the group bonded to the oxygen atom is a monovalent nonmetallic atomic group excluding hydrogen can be used. Preferred substituted oxy groups include alkoxy groups, aryloxy groups, acyloxy groups, carbamoyloxy groups, N-alkylcarbamoyloxy groups, N-arylcarbamoyloxy groups, N, N-dialkylcarbamoyloxy groups, N, N-diarylcarbamoyloxy groups. Group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, phosphonooxy group, and phosphonatoxy group.
As the alkyl group and aryl group in these, the R ^{1 to} R ⁴ , R ⁵ and R ⁶ , the alkyl group in Z ¹ and Z ² , the same substituted alkyl group, the R ^{1 to} R ⁴ , Z ¹ and Z The aryl group in ² and those exemplified as the substituted aryl group can be mentioned. Examples of the acyl group (R ⁸ CO—) in the acyloxy group include those exemplified for R ⁸ as the above alkyl group, substituted alkyl group, aryl group, and substituted aryl group.
Among these substituted oxy groups, an alkoxy group, an aryloxy group, an acyloxy group, and an arylsulfoxy group are more preferable. Specifically, a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butyloxy group, a pentyloxy group Group, hexyloxy group, 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 group, mesityloxy group, cumenyloxy group Methoxyphenyl group, ethoxyphenyl group, chlorophenyl group, bromophenyl group, acetyloxy group, benzoyloxy group, naphthyloxy group, a phenylsulfonyloxy group, a phosphonooxy group, phosphonatoxy group, and the like.

Examples of the halogen atom in R ⁵ and R ⁶ include fluorine, chlorine, bromine, iodine and the like.
R ¹ and R ² , or R ³ and R ⁴ may be bonded to form a ring, R ¹ or R ² and R ⁵ may be bonded, and R ³ or R ⁴ and R ⁶ may be bonded. A ring may be formed, and R ¹ and R ² may be bonded to another R ⁵ , or R ³ and R ⁴ may be bonded to another R ⁶ to form a ring. When n or m is 2 or more, R ⁵ or R ⁶ may be bonded to each other to form a ring. N and m each independently represents an integer of 0 to 4. At least one of Z ¹ or Z ² is preferably a hydrogen atom or an alkyl group.

The trimethine group and the pentamethine group in Q may have a substituent, and as the substituent, a monovalent nonmetallic atomic group excluding hydrogen is used. Preferable examples include an alkyl group, aryl group, alkenyl group and alkynyl group which may have a substituent. Specific examples of the alkyl group and aryl group, wherein R ¹ ~R ^4, R ⁵ and R ^6, and the alkyl group in Z ¹ and Z ^2, wherein R ¹ to R ^4, the aryl group in Z ¹ and Z ² The example given as is preferred. Examples of the alkenyl group include a vinyl group, a phenyl vinyl group, a dialkylaminophenyl vinyl group, a 1-propenyl group, a 1-butenyl group, a cinnamyl group, and a 2-chloro-1-ethenyl group. Examples of the alkynyl group include ethynyl group, 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group, phenylethynyl group and the like.
Further, as preferred examples of the substituent for Q, a halogen atom (-F, -Br, -C1, -I), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio Group, 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-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfo Xyl group, acylthio group, acylamino group, N-a Killacylamino 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 group, N'-aryl-N-arylureido group, N ', N '-Diaryl-N-alkylureido group, N', N'-diaryl-N-arylureido 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, N-aryl-N-aryloxycarbonylamino group, formyl group, carboxyl group, and its conjugate base group, 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, A sulfo group (—SO ₃ H) and its conjugate base (hereinafter referred to as “sulfonato group”). ), Alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group , N- alkyl -N- arylsulfamoyl group, N- acylsulfamoyl group and a conjugate base group, N- alkylsulfonylsulfamoyl group (representing -SO ₂ NHSO ₂ R, R is an alkyl group.) and a conjugated base group, N- aryl sulfonylsulfamoyl group (-SO ₂ NHSO ₂ A , Ar represents an aryl group) and a conjugated base group, N- alkylsulfonylcarbamoyl group (-CONHSO ₂ R, R represents an alkyl group) and a conjugated base group, N- ants -.. Rusuru Honi carbamoyl group ( —CONHSO ₂ Ar, Ar represents an aryl group) and its conjugate base group, alkoxysilyl group (—Si (OR) ₃ , R represents an alkyl group), 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 its conjugate base group (hereinafter referred to as “phosphonate group”). ), dialkylphosphono group (-PO ₃ R ^2, R represents an alkyl group.), diarylphosphono group (-PO ₃ Ar _2, Ar represents an aryl group.), alkyl Riruhosuhono group _{(-PO 3 (R) (Ar} ), R is an alkyl group, Ar represents an aryl group.), Monoalkyl phosphono group _{(-PO 3 H (R),} R represents an alkyl group.) And Its conjugated base group (hereinafter referred to as “alkylphosphonate group”), monoarylphosphono group (—PO ₃ H (Ar), Ar represents an aryl group) and its conjugated base group (hereinafter referred to as “arylphosphonate”). Nato group ”), phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as“ phosphonatoxy group ”), dialkylphosphonooxy group (—OPO ₃ R ₂ , R represents an alkyl group) ), A diarylphosphonooxy group (—OPO ₃ Ar ₂ , Ar represents an aryl group). ), An alkylarylphosphonooxy group (—OPO ₃ (R) (Ar), R represents an alkyl group, Ar represents an aryl group), a monoalkylphosphonooxy group (—OPO ₃ H (R), R is Represents an alkyl group) and its conjugate base group, monoarylphosphonooxy group (—OPO ₃ H (Ar), Ar represents an aryl group) and its conjugate base group, cyano group, nitro group, acyl group ( R ¹⁰ CO—; R ¹⁰ may include a hydrogen atom, R ^{1 to} R ⁴ , R ⁵ and R ⁶ , an alkyl group in Z ¹ and Z ^2, and a substituent for the alkyl group Examples thereof include the same aryl groups, alkenyl groups, and alkynyl groups mentioned above.

In the above substituents, specific examples of the alkyl group represented by R include those similar to the alkyl groups in R ^{1 to} R ⁴ , R ⁵ and R ⁶ , and Z ¹ and Z ² . Specific examples of the aryl group represented by Ar include the same aryl groups listed as substituents for the alkyl group.

  Among these substituents, more preferred are an alkyl group, an aryl group, an alkenyl group, a halogen atom (-F, -Br, -C1, -I), an alkoxy group, a hydroxyl group, an aryloxy group, an alkylthio group, an arylthio group. Group, N-alkylamino group, N, N-dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, formyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group , Carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfamoyl group , N, N-dia Killsulfamoyl group, N-arylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group, phosphonato group, dialkylphosphono group, diarylphosphono group, monoalkylphosphono group, alkylphosphonato Group, monoarylphosphono group, arylphosphonate group, phosphonooxy group, phosphonatoxy group, acyl group and the like.

  Q may form a ring together with a divalent organic group that is a substituent introduced into the methine chain, such as an alkylene group or an alkenylene group. Except for 4) to 7). The formed ring may have a substituent, and examples of the substituent include those similar to the substituent in Q.

In the general formula (I), X ⁻ represents a counter anion. When the charge is neutralized in the molecule, there is no counter anion.
As the counter anion, for example, the formula MY ₁ ⁻ (M is an atom selected from B, P, As, Sb, Fe, Al, Sn, Zn, Ti, Cd, Mo, W, Zr, preferably B , P, As, Sb, Y represents a halogen atom, and l is an integer of 1 to 6, or the formula MY _l-1 (OH) ⁻ (wherein M, Y and l are the above In addition to those represented by (2), Br ⁻ , Cl ⁻ , I ⁻ , NO ₃ ^{— and the} like can be mentioned. Preferred counter anions represented by the formula MY _l ⁻ include BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ^{− and the} like. Particularly preferred among these are, SbF ₆ ^- is. Further, the formula MY _l-1 (OH) ^- Preferred counter anion represented by, SbF ₅ (OH) ^- can be exemplified.

Furthermore, as other counter anions,
1) perchlorate ion,
2) trifluoromethyl sulfite ion,
3) methanesulfonate ion,
4) ethane sulfonate ion,
5) 1-propanesulfonic acid ion,
6) 2-propanesulfonic acid ion,
7) n-butanesulfonic acid ion,
8) allyl sulfonate ion,
9) 10-camphorsulfonic acid ion,
10) trifluoromethanesulfonate ion,
11) pentafluoroethanesulfonic acid ion,
12) benzenesulfonate ion,
13) p-toluenesulfonic acid ion,
14) 3-methoxybenzenesulfonate ion,
15) 4-methoxybenzenesulfonate ion,
16) 4-hydroxybenzenesulfonate ion,
17) 4-chlorobenzenesulfonic acid ion,
18) 3-nitrobenzenesulfonate ion,
19) 4-nitrobenzenesulfonate ion,
20) 4-acetylbenzenesulfonate ion,
21) pentafluorobenzenesulfonate ion,
22) 4-dodecylbenzenesulfonate ion,
23) mesitylene sulfonate ion,
24) 2,4,6-triisopropylbenzenesulfonate ion,
25) 2-hydroxy-4-methoxybenzophenone-5-sulfonate ion,
26) Dimethyl-5-sulfonic acid ion of isophthalate,
27) Diphenylamine-4-sulfonate ion,
28) 1-naphthalenesulfonic acid ion,
29) 2-Naphthalenesulfonate ion,
30) 2-naphthol-6-sulfonate ion,
31) 2-naphthol-7-sulfonate ion,
32) Anthraquinone-1-sulfonate ion,
33) Anthraquinone-2-sulfonic acid ion,
34) 9,10-dimethoxyanthracene-2-sulfonic acid ion,
35) 9,10-diethoxyanthracene-2-sulfonic acid ion,
36) Quinoline-8-sulfonate ion,
37) 8-hydroxyquinoline-5-sulfonate ion,
38) 8-anilino-naphthalene-1-sulfonic acid ion and the like.

Next, a method for producing the infrared absorbent represented by the general formula (I) will be described. The infrared absorbent represented by the general formula (I) is justus Liebigs Ann. Chem. 623, 1959
Years 204-216, Ukr. Khim. Zh. 22, 1956, pp. 347-348, Chem. Heterocycl. Compd. 18, 1982, 334-336; Heterocycl. Chem. 25, 1988, pp. 1321-1325, and Japanese Laid-Open Patent Publication No. 60-231766. Synthesis examples are given below.

Synthesis Example 1 (Synthesis of IR-5)
(1) After dissolving 50.8 g of 4-N, N-diethylaminobenzaldehyde and 12.1 g of cyclopentanone in 200 ml of ethanol, 31 g of 10% aqueous sodium hydroxide solution was added, and the mixture was stirred at 40 ° C. to 50 ° C. For 8 hours, the precipitated crystals were filtered off, washed with 80 ml of ethanol and 200 ml of water and dried to give 2,5-bis (4-N, N-diethylaminobenzylidene) cyclopentanone orange crystals. 52.5 g was obtained.
(2) 1,5-bis (4-N, N-diethylaminobenzylidene) cyclopentanone 12.1 g was dissolved in a mixed solvent of 100 g of tetrahydrofurfuryl alcohol and 150 g of tetrahydrofuran, and 1.1 g of sodium borohydride The mixture was reacted at 30 ° C. to 45 ° C. for 8 hours, and then 5.5 g of a 48% tetrafluoroboric acid and acetic acid 30 g mixture was poured at room temperature, and the precipitated dark green crystals were collected by filtration, washed with water and dried. As a result, 5.5 g of infrared absorber IR-5 was obtained.

Synthesis Example 2 (Synthesis of IR-18)
(1) After dissolving 51.8 g of 2- (N-ethylanilino) ethanol and 31.7 g of triethylamine in 300 ml of acetone, 25 g of acetyl chloride was slowly added while cooling the reaction solution with ice water, and the mixture was stirred at room temperature for 6 hours. The reaction was continued for a period of time and 200 ml of water was poured. The organic layer was extracted with ethyl acetate and dried over sodium sulfate, and then the solvent was distilled off under reduced pressure to obtain 64.9 g of 2- (N-ethylanilino) ethyl acetate.
(2) After adding 55.8 g of phosphoryl chloride to 26.6 g of dimethylformamide under ice-cooling, a solution of 63.0 g of 2- (N-ethylanilino) ethyl acetate and 40 ml of dimethylformamide was slowly added at room temperature and stirred at room temperature. The mixture was allowed to react for 6 hours, and poured into an aqueous solution of 150 g of sodium acetate under ice cooling. The organic layer was extracted with ethyl acetate, the solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography to obtain 60.2 g of 2- (ethyl (4-formylphenyl) amino) ethyl acetate.
(3) A mixture of 51.0 g of 4-N, N-diethylaminobenzaldehyde, 72.7 g of cyclopentanone, 19.0 g of 85% potassium hydroxide pellets and 450 ml of water was heated to reflux for 25 hours and then excess cyclopentanone. Was distilled off by a conventional method, and the precipitated crystals were separated by filtration, recrystallized with ethanol and then dried to obtain 45.5 g of orange crystals of 2- (4- (diethylamino) benzylidene) cyclopentanone.
(4) After dissolving 40.5 g of 2- (ethyl (4-formylphenyl) amino) ethyl acetate and 41.8 g of 2- (4- (diethylamino) benzylidene) cyclopentanone in 120 ml of ethanol, 10% 19 g of an aqueous sodium hydroxide solution was added, and the mixture was reacted at 40 ° C. to 50 ° C. with stirring for 6 hours. The precipitated crystals were separated by filtration, washed with 50 ml of ethanol and 150 ml of water, dried, and 2- (4- ( 38.5 g of orange crystals of diethylamino) benzylidene) -5- (4- (ethyl (2-hydroxyethyl) amino) benzylidene) cyclopentanone were obtained.
(5) 2- (4- (diethylamino) benzylidene) -5- (4- (ethyl (2-hydroxyethyl) amino) benzylidene) cyclopentanone (10.5 g) was added to 100 g of tetrahydrofurfuryl alcohol and 150 g of tetrahydrofuran. After dissolving in a mixed solvent and adding 1.1 g of sodium borohydride and reacting at 30 ° C. to 45 ° C. for 8 hours, a mixture of 4.2 g of 60% perchloric acid and 3 g of acetic acid is poured at room temperature, The precipitated dark green crystals were collected by filtration, washed with water and dried to obtain 4.3 g of infrared absorber IR-18.

Synthesis Example 3 (Synthesis of IR-30)
(1) 49.6 g of 4- (dimethylamino) benzophenonephenone was dissolved in 120 ml of tetrahydrofuran, added to 250 ml of 1N tetrahydrofuran solution of methylmagnesium bromide with ice cooling, and the reaction solution was heated to reflux for 1 hour, then ammonium chloride. An aqueous solution was added, and the mixture was treated by a conventional method to obtain an alcohol intermediate. Subsequently, the obtained alcohol intermediate was dissolved in 200 ml of acetic anhydride and refluxed for 2 hours, and then the solvent was distilled off under reduced pressure to obtain 39 g of dimethyl (4- (1-phenylvinyl) phenyl) amine.
(2) 28 g of dimethyl (4- (1-phenylvinyl) phenyl) amine and 22 g of 4-dimethylaminocinnamic aldehyde are dissolved in 200 ml of acetic anhydride and refluxed for 3 hours, and then the reaction solution is cooled to room temperature. Then, a mixture of 11 ml of 70% perchloric acid and 600 ml of acetic acid was slowly added and refluxed again for 10 minutes. The reaction mixture was cooled, 600 ml of water was added, the precipitate was filtered off, washed with water and then recrystallized with a mixed solvent of ethanol and water to obtain 12 g of infrared absorber IR-30.

Synthesis Example 4 (Synthesis of IR-46)
(1) After dissolving 42.8 g of 4-N, N-dimethylaminobenzaldehyde and 14.1 g of cyclohexanone in 200 ml of ethanol, 31 g of 10% aqueous sodium hydroxide solution was added, and the mixture was stirred at 40-50 ° C. The mixture was allowed to react for 7 hours, and the precipitated crystals were filtered off, washed with 80 ml of ethanol and 200 ml of water and dried to give orange crystals of 2,6-bis (4-N, N-dimethylaminobenzylidene) cyclohexanone. 2 g was obtained.
(2) 9.0 g of 2,6-bis (4-N, N-dimethylaminobenzylidene) cyclohexanone was dissolved in a mixed solvent of 100 g of tetrahydrofurfuryl alcohol and 150 g of tetrahydrofuran, and 1.1 g of sodium borohydride was dissolved. In addition, after reacting at 30 ° C. to 45 ° C. for 8 hours, a mixture of 4.8 g of p-toluenesulfonic acid hydrate, 30 g of acetic acid and 35 ml of water was poured at room temperature, and the precipitated dark green crystals were collected by filtration. Wash with water and dry. 4.3g of infrared absorber IR-46 was obtained.

Specific examples of the infrared absorbent represented by the general formula (I) are given below, but the infrared absorbent of the present invention is not limited to these specific examples.

These infrared absorbers are added in a proportion of 0.01 to 50% by mass, preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, based on the total solid content of the uppermost layer. Can do. If the addition amount is less than 0.01% by mass, an image cannot be formed in this image recording layer. If the addition amount exceeds 50% by mass, the non-image area may be stained.
In the present invention, by using such an infrared absorber, the solubility of the developer is excellent, and good image forming properties are exhibited even if the amount added to the uppermost layer is reduced.

  In addition to the infrared absorber, other pigments or dyes having infrared absorptivity can be added to the uppermost layer in the present invention for the purpose of improving image forming properties. Examples of pigments include commercially available pigments, Color Index (CI) Handbook, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “ Known pigments such as those described in “Printing Ink Technology”, published by CMC Publishing, 1984) can be used.

  Examples of the pigment 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, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used.

  These pigments may be used after being subjected to a surface treatment, such as a method of surface coating with a resin or wax, a method of attaching a surfactant, a reactive substance (for example, a silane coupling agent or an epoxy compound, A method of bonding a polyisocyanate or the like) to the pigment surface is conceivable. The above-mentioned surface treatment methods are described in “Characteristics and Applications of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. When the particle diameter of the pigment is less than 0.01 μm, it is not preferable from the viewpoint of stability of the dispersion in the image recording layer coating solution, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the image recording layer. As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like 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 Applied Technology" (CMC Publishing, 1986).

  As the dye, known dyes such as commercially available dyes and dyes described in “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, diimonium dyes, and aminium dyes. In the present invention, when an image is formed by a laser that emits infrared light or near infrared light, among these pigments or dyes, those that absorb infrared light or near infrared light are particularly preferable.

  Carbon black is preferably used as a pigment that absorbs such infrared light or near infrared light. 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, and JP-A-60-78787. Cyanine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., methine dyes described in JP-A-58-112793, Naphthoquinone dyes described in JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. Squaryllium dyes described in JP-A-58-112792, etc., cyanine dyes described in British Patent 434,875, US Pat. No. 5,380,635 Dihydroperimidine squarylium dyes described can be mentioned.

  Further, near-infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzos described in US Pat. No. 3,881,924 ( Thio) pyrylium salts, trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59 No. 41363, 59-84248, 59-84249, 59-146063, 59-146061, and the like, and cyanine dyes described in JP-A-59-216146 And pentamethine thiopyrylium salt described in US Pat. No. 4,283,475, and Japanese Patent Publication Nos. 5-13514 and 5-19702. Pyrylium compounds disclosed in JP, Epolight III-178, Epolight III-130, Epolight III-125, Epolight IV-62A and the like are particularly preferably used. Another particularly preferable example of the dye includes near-infrared absorbing dyes described as formulas (I) and (II) in US Pat. No. 4,756,993.

  These pigments or dyes are preferably 0.01 to 50% by mass, more preferably 0.1 to 10% by mass, based on the total solid content of the uppermost layer, from the viewpoints of sensitivity, uniformity of the image recording layer, and durability. In the case of a dye, 0.5 to 10% by mass is particularly preferable. In the case of a pigment, 3.1 to 10% by mass is particularly preferable.

  In addition, when using together the infrared absorber represented by general formula (I), and said other infrared absorber, the usage-amount of the infrared absorber represented by general formula (I) in all the infrared absorbers Is preferably 1 to 99% by mass, more preferably 5 to 95% by mass, and particularly preferably 10 to 90% by mass.

[Alkali-soluble resin]
The uppermost layer in the image forming material of the present invention contains a water-insoluble and alkali-soluble resin (hereinafter simply referred to as “alkali-soluble resin”) in addition to the infrared absorber.
As the alkali-soluble resin, a resin containing an acidic group in the main chain and / or side chain in the resin can be used.
Here, as the acidic group, acidic groups listed in the following (1) to (6) are preferable in terms of development resistance and solubility in an alkaline aqueous solution.

(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
(—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R)
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )

  In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrogen atom or a hydrocarbon group which may have a substituent. .

  Among the alkali-soluble resins having an acidic group selected from the above (1) to (6), (1) an alkali-soluble resin having a phenol group, (2) a sulfonamide group, and (3) an active imide group is preferable. An alkali-soluble resin having (1) a phenol group or (2) a sulfonamide group is most preferred from the viewpoint of sufficiently ensuring solubility in an alkaline developer, development latitude, and film strength.

As alkali-soluble resin which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.
(1) Examples of the alkali-soluble resin having a phenol group include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, m− / p. A novolac resin such as a condensation polymer of mixed cresol and formaldehyde, a condensation polymer of phenol and cresol (m-, p- or m- / p-mixed) and formaldehyde, and pyrogallol and acetone. Can be mentioned.

Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned.
Examples of the compound having a phenol group in the side chain include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group in the side chain.

  (2) As an alkali-soluble resin having a sulfonamide group, for example, a polymer composed of a minimum constituent unit derived from a compound having a sulfonamide group as a main constituent can be mentioned. Examples of such compounds include compounds each having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. Among these, low molecular weight compounds having an acryloyl group, an allyl group, or a vinyloxy group, and an aminosulfonyl group or a substituted sulfonylimino group in the molecule are preferable. For example, they are represented by the following general formulas (i) to (v). Compounds.

[In the general formulas (i) to (v), X ¹¹ and X ¹² each independently represent —O— or —NR ¹⁷ . R ¹¹ and R ¹⁴ each independently represents a hydrogen atom or —CH ₃ . R ¹² , R ¹⁵ , R ¹⁹ , R ²² and R ²⁶ each independently represent a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a substituent. R ¹³ , R ¹⁷ and R ²³ each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R ¹⁶ and R ²⁷ each independently represent a C 1-12 alkyl group, cycloalkyl group, aryl group, or aralkyl group that may have a substituent. R ¹⁸ , R ²⁰ and R ²⁴ each independently represents a hydrogen atom or —CH ₃ . R ²¹ and R ²⁵ each independently represent a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a single bond or a substituent. Y ¹¹ and Y ¹² each independently represents a single bond or —CO—. ]

  Among the compounds represented by the general formulas (i) to (v), the compounds used for the alkali-soluble resin in the present invention include, in particular, m-aminosulfonylphenyl methacrylate and N- (p-aminosulfonylphenyl) methacrylamide. N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

  (3) As an alkali-soluble resin having an active imide group, for example, a polymer composed of a minimum constituent unit derived from a compound having an active imide group as a main constituent can be mentioned. Examples of such compounds include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups.

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

(4) As an alkali-soluble resin having a carboxylic acid group, for example, a minimum structural unit derived from a compound having at least one carboxylic acid group and one or more polymerizable unsaturated groups in the molecule is used as a main constituent component. Can be mentioned.
(5) As an alkali-soluble resin having a sulfonic acid group, for example, a minimum structural unit derived from a compound having one or more sulfonic acid groups and polymerizable unsaturated groups in the molecule is used as a main constituent component. Can be mentioned.
(6) As an alkali-soluble resin having a phosphoric acid group, for example, a minimum structural unit derived from a compound having at least one phosphoric acid group and a polymerizable unsaturated group in the molecule is used as a main constituent component. Can be mentioned.

  The alkali-soluble resin according to the present invention is preferably a polymer compound obtained by polymerizing two or more of monomers having an acidic group selected from the above (1) to (6).

Furthermore, in addition to one or two or more polymerizable monomers among the monomers having an acidic group selected from the above (1) to (6), a polymer compound obtained by copolymerizing other polymerizable monomers It is preferable that As a copolymerization ratio in this case, it is preferable that the monomer which provides alkali solubility is contained 10 mol% or more, and what contains 20 mol% or more is more preferable. When the copolymerization component of the monomer that imparts alkali solubility is less than 10 mol%, alkali solubility tends to be insufficient, and the development latitude tends to decrease.
Here, as other polymerizable monomers that can be used, the following compounds (m1) to (m12) can be exemplified, but the present invention is not limited to these.

(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.
(M5) 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.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

The alkali-soluble resin in the present invention is preferably a homopolymer or copolymer of a polymerizable monomer having (1) a phenol group, (2) a sulfonamide group, or (3) an active imide group. Preferred is a homopolymer or copolymer of a polymerizable monomer having a sulfonamide group, such as aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide. .
The alkali-soluble resin preferably has a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .
In the present invention, when the alkali-soluble resin is a resin such as a phenol formaldehyde resin or a cresol aldehyde resin, the weight average molecular weight is 500 to 20,000, and the number average molecular weight is preferably 200 to 10,000. .

  These alkali-soluble resins may be used alone or in combination of two or more. The addition amount of the alkali-soluble resin is preferably 30 to 99% by mass, more preferably 40 to 95% by mass, and more preferably 50 to 90% by mass in the total solid content of the uppermost layer from the viewpoint of sensitivity and durability of the image recording layer. Particularly preferred.

[Dissolution inhibitor]
In the uppermost layer according to the present invention, an onium salt, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, a polyfunctional amine compound, or the like, such as an onium salt, an aromatic sulfonic acid ester compound, or a polyfunctional amine compound is adjusted to adjust the solubility in the developer. It is preferable to add a so-called dissolution inhibitor that improves the dissolution inhibition function. Of these, dissolution inhibitors such as onium salts, o-quinonediazide compounds, and sulfonic acid alkyl esters are preferred because they are thermally decomposable and substantially reduce the solubility of the alkali-soluble resin when not decomposed. .

  Examples of the onium salt used in the present invention include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A Nos. 5-158230 and 11-143064, etc .; US Pat. Nos. 4,069,055 and 4,069,056 Ammonium salts described in JP-A-3-140140, JP-A-2002-229186, etc .; C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055, 4,069,056 and the like; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848, JP-A-2-296514, etc. Iodonium salts described in the Japanese Patent Publication; V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 Sulfonium salts described in the specifications of No. 626, No. 3,604,580, No. 3,604,581, etc .; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979); C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).

  Among these onium salts, diazonium salts and quaternary ammonium salts are particularly preferable from the viewpoints of dissolution inhibition ability and thermal decomposability. In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable. Moreover, as a quaternary ammonium salt, the quaternary ammonium salt shown by (1)-(10) of Unexamined-Japanese-Patent No. 2002-229186 is preferable.

  The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide helps the solubility of the image recording layer by both the effects of losing the ability to suppress the dissolution of the binder due to thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. The compounds described in pages 339 to 352 of “Light-sensitive systems” by John Coley (John Wiley & Sons. Inc.) can be used, and in particular, o-quinonediazide reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. The sulfonic acid esters or sulfonic acid amides are preferred. Further, benzoquinone (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2)-described in U.S. Pat. Nos. 3,046,120 and 3,188,210. Esters of diazide-5-sulfonic acid chloride and phenol-formaldehyde resins are also preferably used.

  Further, esters of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride with phenol-formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-174741, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1, No. 267,005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

  When an onium salt and / or o-quinonediazide compound is added as a degradable dissolution inhibitor, the amount added is preferably 1 to 10% by mass, more preferably 1 to 5% by mass, based on the total solid content of the uppermost layer. Especially preferably, it is the range of 1-2 mass%. These compounds can be used alone, but may be used as a mixture of several kinds.

  Moreover, when adding other degradable dissolution inhibitors described above other than the onium salt and the o-quinonediazide compound, the addition amount is preferably 0.1 to 5% by mass relative to the total solid content of the uppermost layer, Preferably it is 0.1-2 mass%, Most preferably, it is 0.1-1.5 mass%. In the present invention, the dissolution inhibitor is preferably contained in the same layer as the binder.

  Further, a dissolution inhibitor having no decomposability may be added, and preferable dissolution inhibitors include sulfonic acid esters, phosphate esters, aromatic carboxylic acid esters described in JP-A-10-268512, Aromatic disulfone, carboxylic acid anhydride, aromatic ketone, aromatic aldehyde, aromatic amine, aromatic ether, etc., lactone skeleton, N, N-diarylamide skeleton, which are also described in JP-A-11-190903, Examples thereof include an acid color-forming dye having a diarylmethylimino skeleton and also serving as a colorant, and nonionic surfactants described in JP-A No. 2000-105454.

When the dissolution inhibitor having no decomposability is added, the addition amount is preferably 0.1 to 40% by mass, more preferably 0.2 to 30% by mass, based on the total solid content of the uppermost layer. Especially preferably, it is 0.5-20 mass%.
When the decomposable dissolution inhibitor and the dissolution inhibitor having no decomposability are used in combination, the amount of the degradable dissolution inhibitor in the total dissolution inhibitor is 1 to 99% by mass. Preferably, it is 5-95 mass%, More preferably, it is 10-90 mass%.

[Other additives]
Moreover, as an additive used for the uppermost layer in this invention, a cyclic acid anhydride, phenols, and organic acids can be mentioned in order to improve a sensitivity. Further, a surfactant, an image colorant, a plasticizer and the like which will be described later can be added.

Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride described in US Pat. No. 4,115,128, Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used.
As phenols, 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.
Examples of organic acids include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755. Is mentioned.
The addition amount of the cyclic acid anhydride, phenols, and organic acids is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably the total solid content of the uppermost layer. It is 0.1-10 mass%.

  In addition to these, epoxy compounds, vinyl ethers, and further, phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group described in JP-A-8-276558, and the inventors previously proposed. A crosslinkable compound having an alkali dissolution inhibiting action described in JP-A-11-160860 can be appropriately added depending on the purpose.

  Further, in the uppermost layer in the present invention, a nonionic surfactant as described in JP-A No. 62-251740 and JP-A No. 3-208514, in order to broaden the processing stability against development conditions, Amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149, siloxane compounds as described in EP950517, and JP-A-11-288093 Fluorine-containing monomer copolymers as described above can be added.

Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like.
Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, N-tetradecyl-N, N-betaine Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.).
The addition amount of the nonionic surfactant and / or amphoteric surfactant is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass, based on the total solid content of the uppermost layer.

  As the siloxane compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany.

Further, a printing-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644, 63-58440, etc. Combinations of trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole compounds and triazine compounds, both of which have excellent temporal stability and give clear printout images.

  As the image colorant, other dyes can be used in addition to the aforementioned salt-forming organic dyes. Examples of 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 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added to the uppermost layer in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the uppermost layer.

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

<Lower layer>
Next, the lower layer of the image forming material of the present invention will be described.
In the lower layer according to the present invention, there are no particular limitations on other components as long as the alkali-soluble resin is an essential component. That is, if necessary, it may contain an infrared absorber and other components similar to those mentioned in the uppermost layer.
As the alkali-soluble resin used for the lower layer, the same resins as those mentioned in the uppermost layer can be used. However, in order to clarify the boundary between the layers, the alkali-soluble resin used for the lower layer is used for the upper layer. It is preferable that the main component is different from the alkali-soluble resin. Examples of the alkali-soluble resin suitably used for the lower layer include a copolymer of N- (p-aminosulfonylphenyl) (meth) acrylamide, (meth) acrylic acid alkyl ester and acrylonitrile, 4-maleimidobenzenesulfonamide and styrene. Although an alkali-soluble resin having a highly polar unit such as a copolymer of (meth) acrylic acid, a copolymer of N-phenylmaleimide and (meth) acrylamide is preferably used, the present invention is not limited thereto. It is not something.

Further, although not particularly limited, in the present invention, the lower layer is preferably a layer having higher alkali solubility than the uppermost layer. By having this characteristic, the exposed portion exhibits excellent development solubility, and for example, even when a developer having reduced activity is used, the exposed portion dissolves rapidly without any remaining film. On the other hand, in the unexposed area, the lower layer does not come into contact with the developer due to the permeation suppressing action of the uppermost layer, so there is no risk of overdevelopment. Therefore, an image forming material with higher sensitivity can be obtained, and an image excellent in discrimination can be formed.
As described above, the composition contained in the uppermost layer can be used similarly for the lower layer, but for the purpose of obtaining a highly soluble lower layer, an infrared absorber represented by the general formula (I), other The preferable content range of the infrared absorber and the dissolution inhibitor is different from the preferable content range of the uppermost layer.
That is, the content of the infrared absorber represented by the general formula (I) and other infrared absorbers is preferably 0.01 to 30% by mass, and 0.1 to 20% by mass in the total solid content of the lower layer. Is more preferable, and 0.5 to 10% by mass is particularly preferable. Moreover, 0.1-30 mass% is preferable in the total solid of a lower layer, as for content of the dissolution inhibitor which expresses a dissolution inhibitory action, 0.2-20 mass% is more preferable, 0.5-10 mass % Is particularly preferred.
In addition, the preferable example of the said infrared absorber and dissolution inhibitor, and the preferable example and preferable addition amount of another composition are the same as that of the case of the said uppermost layer.

<Formation of image recording layer>
The image recording layer according to the present invention can be formed by dissolving each component of the lower layer and the uppermost layer in a solvent and coating the solution on a suitable support. Further, depending on the purpose, an undercoat layer, a protective layer, a backcoat layer and the like, which will be described later, can be formed in the same manner.
Solvents used here include 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, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited. These solvents are used alone or in combination.
The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.
The coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the use, but generally the coating amount after drying the lower layer is 0.1 to 5.0 g / m ^2. Preferably, 0.2 to 3.0 g / m ² is more preferable. As the coating amount after drying of the top layer is preferably 0.01~5.0g / m ^2, more preferably ^{0.03~3.0g / m 2, 0.05~2.0mg / m} 2 Is most preferred.

  Various methods can be used for applying the image recording layer coating solution. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating. Etc. As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the image recording layer decrease.

As a method for forming the two layers separately, for example, a method using a difference in solvent solubility between the component contained in the lower layer and the component contained in the uppermost layer, or after applying the uppermost layer, rapid And a method of drying and removing the solvent.
Hereinafter, although these methods are described, the method of applying the two layers separately is not limited thereto.

  As a method of utilizing the difference in solvent solubility between the component contained in the lower layer and the component contained in the uppermost layer, when applying the coating solution for the uppermost layer, any of the components contained in the lower layer is insoluble. Is used. Thereby, even if it carries out 2 layer application | coating, it becomes possible to isolate | separate each layer clearly and to make a coating film. For example, as the lower layer component, a component insoluble in a solvent such as methyl ethyl ketone or 1-methoxy-2-propanol that dissolves the alkali-soluble resin that is the uppermost layer component is selected, and the lower layer is formed using a solvent system that dissolves the lower layer component. After coating and drying, the upper layer component mainly composed of an alkali-soluble resin is dissolved in methyl ethyl ketone, 1-methoxy-2-propanol or the like, and coating and drying can be performed to form two layers.

  Next, after applying the second layer (uppermost layer), as a method of drying the solvent very quickly, a method of blowing high-pressure air from a slit nozzle installed substantially perpendicular to the web running direction, steam, etc. Examples thereof include a method in which heat energy is applied as conduction heat from the lower surface of the web from a roll (heating roll) supplied with a heating medium, or a combination of these methods.

  The image recording layer according to the present invention may contain a surfactant for improving the coating property, for example, a fluorosurfactant as described in JP-A-62-170950. . A preferable addition amount is 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass in the total solid content of each of the uppermost layer and the lower layer.

<Support>
The support used in the image forming material of the present invention is a dimensionally stable plate-like material, and is not particularly limited as long as it satisfies physical properties such as required strength and flexibility. Paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, butyric acid) Cellulose, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper on which a metal as described above is laminated or vapor-deposited, or plastic film.
As the support applicable to the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is generally 10% by mass or less. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

  Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can also be used. The roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment as necessary, and then subjected to anodization treatment if desired in order to enhance the water retention and wear resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, 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 electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used and thus cannot be specified in general. In general, however, a solution having an electrolyte concentration of 1 to 80% by mass, a liquid temperature of 5 to 70 ° C., and a current density of 5 to 60 A. / Dm ² , voltage 1 to 100 V, electrolysis time 10 seconds to 5 minutes are suitable. When the amount of the anodized film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image part of the printing plate is easily scratched, so that the ink adheres to the scratched part during printing. “Scratches and dirt” are likely to occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. Examples of the hydrophilization treatment used in the present invention include U.S. Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There is an alkali metal silicate (for example, aqueous sodium silicate) method as disclosed in the literature. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and U.S. Pat. Nos. 3,276,868, 4,153,461, 4,689,272, etc. For example, a method of treating with polyvinylphosphonic acid as disclosed in JP-A No. 1993-133.

<Undercoat layer>
The image forming material of the present invention is provided with an image recording layer as described above on a support, but an undercoat layer can be provided between the support and the lower layer, if necessary. By providing this undercoat layer, the undercoat layer between the support and the image recording layer functions as a heat insulating layer, and the heat generated by the infrared laser exposure does not diffuse to the support and is used efficiently. Therefore, there is an advantage that the sensitivity can be increased. In addition, the image recording layer according to the present invention is located on the exposed surface or in the vicinity thereof even when the undercoat layer is provided, so that the sensitivity to the infrared laser is well maintained.
In the unexposed area, the image recording layer itself that is impervious to the alkaline developer functions as a protective layer for the undercoat layer, so that the development stability is improved and the discrimination is excellent. It is considered that an image is formed and the stability over time is ensured, and in the exposed portion, the components of the image recording layer whose dissolution inhibiting action is released are quickly dissolved and dispersed in the developer. Since the undercoat layer itself that is present adjacent to the support is made of an alkali-soluble resin, the solubility in a developer is good, for example, even when using a developer with reduced activity, It is considered that this undercoat layer is useful because it dissolves quickly without generating a residual film and contributes to improvement of developability.

  Various organic compounds are used as the primer layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent Organic phosphonic acids such as naphthyl phosphonic acid, alkyl phosphonic acid, glycero phosphonic acid, methylene diphosphonic acid and ethylene diphosphonic acid, phenyl phosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid which may have a substituent Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid and other aminophosphinic acids, glycine, β-alanine and other amino acids, and triethanolamine hydrochloride Having a hydroxy group such as Selected from the hydrochloride salt of amine may be used by mixing them one or two or more.

  Furthermore, an undercoat layer containing at least one compound selected from the group of organic polymer compounds having a structural unit represented by the following formula is also preferred.

R ³¹ represents a hydrogen atom, a halogen atom or an alkyl group, and R ³² and R ³³ each independently represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, —OR ³⁴ , -COOR ³⁵ , -CONHR ³⁶ , -COR ³⁷ or -CN, or R ³² and R ³³ may be bonded to form a ring, and R ^{34 to} R ³⁷ are each independently an alkyl group or an aryl group. V represents a hydrogen atom, a metal atom, or N R ³⁸ R ³⁹ R ⁴⁰ R ⁴¹ , and R ^{38 to} R ⁴¹ each independently represents a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group. Alternatively, R ³⁸ and R ³⁹ may combine to form a ring, and k represents an integer of 1 to 3.
Specific examples of the substituent include R ^{1 to} R ⁴ , R ⁵ and R ⁶ , and an alkyl group in Z ¹ and Z ^2, and the same examples as those described above.

Moreover, as a suitable undercoat layer component in the present invention, there can be mentioned a polymer compound having a component having an acid group and a component having an onium group, as described in JP-A No. 2000-241962. Specific examples include a copolymer of a monomer having an acid group and a monomer having an onium group. The acid group is preferably an acid group having an acid dissociation index (pKa) of 7 or more, more preferably —COOH, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , — CONHSO ₂ — or —SO ₂ NHSO ₂ —, particularly preferably —COOH. Specific examples of the monomer having an acid group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, and styrene having the acid group. Preferred as the onium salt is an onium group comprising an atom of Group V or Group VI of the periodic table, more preferred is an onium salt comprising a nitrogen atom, a phosphorus atom or a sulfur atom, and particularly preferred is an onium salt comprising a nitrogen atom. It is salt. Specific examples of the monomer having an onium salt include styrene having a substituent containing an onium group such as a methacrylate having an ammonium group in the side chain, a methacrylamide, a substituent containing an onium group such as a quaternary ammonium group, and the like. It is done.
Furthermore, compounds described in JP-A No. 2000-108538, Japanese Patent Application No. 2002-257484, Japanese Patent Application No. 2003-78699, and the like can be used as necessary.

These undercoat layers can be provided by the following method. That is, a solution in which the above organic compound is dissolved in an organic solvent such as methanol, ethanol, methyl ethyl ketone, or water, or a mixed solvent thereof is prepared, applied to an aluminum plate, and dried. In this method, an aluminum plate is immersed to adsorb the compound, and then washed and dried with water or the like. In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image forming material. The coating amount of the undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. Moreover, even if it exceeds 200 mg / m < ² >, it is the same.

<Image formation>
The image forming material of the present invention is imaged by heat. Specifically, direct image-like recording using a thermal recording head, scanning exposure using an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, and the like are used, but a semiconductor that emits infrared light having a wavelength of 700 to 1200 nm. Exposure by a solid high-power infrared laser such as a laser or a YAG laser is suitable.

The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec, and the energy applied to the recording material is preferably 10 to 500 mJ / cm ² .

<Developer and development processing>
The developer that can be applied to the present invention is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. As a developer (hereinafter referred to as a developer including a replenisher), a conventionally known alkaline aqueous solution can be used. For example, sodium silicate, potassium silicate, tribasic sodium phosphate, triphosphoric acid Potassium, tribasic ammonium phosphate, dibasic sodium phosphate, dibasic potassium phosphate, dibasic ammonium phosphate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium borate, Examples include inorganic alkali salts such as potassium borate, ammonium borate, sodium hydroxide, ammonium hydroxide, potassium hydroxide, and lithium hydroxide. Moreover, 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 listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

  Among the alkaline aqueous solutions described above, as a developer exhibiting particularly advantageous effects, a so-called “silicate developer” containing an alkali silicate as a base or containing an alkali silicate by mixing a silicon compound with a base. And a so-called “non-silicate developer” that does not contain an alkali silicate and contains a non-reducing sugar (an organic compound having a buffering action) and a base.

In the former, the aqueous solution of alkali metal silicate is a ratio of silicon oxide SiO ₂ which is a component of silicate and alkali metal oxide M ₂ O (generally expressed as a molar ratio of [SiO ₂ ] / [M ₂ O]. ) And the density, the developability can be adjusted. For example, as disclosed in JP-A-54-62004, the SiO ₂ / Na ₂ O molar ratio is 1.0 to 1.5 (that is, [SiO ₂ ] / [Na ₂ O] is 1.0 to 1.5), and an aqueous solution of sodium silicate having a SiO ₂ content of 1 to 4 mass% is disclosed in JP-B-57-7427. As described, [SiO ₂ ] / [M] is 0.5 to 0.75 (ie, [SiO ₂ ] / [M ₂ O] is 0.5 to 0.75), and SiO ₂ Concentration of 1 to 4% by weight, and the developer contains gram atoms of all alkali metals present therein. In the quasi containing potassium at least 20%, aqueous solution of an alkali metal silicate is preferably used.

  Further, the latter “non-silicate developer” does not deteriorate the surface of the image recording layer and can maintain the image recording layer in a good state. Is more preferable. An image forming material such as the present invention generally has a narrow development latitude and a large change in image line width due to the pH of the developer, but non-silicate developers have a non-reducing sugar having a buffering property that suppresses fluctuations in pH. Since it is contained, it is more advantageous than the case of using a developing solution containing silicate. Furthermore, since non-reducing sugars are less likely to contaminate conductivity sensors, pH sensors and the like for controlling liquid activity compared to silicates, non-silicate developers are advantageous in this respect as well. In addition, the effect of improving the discrimination is remarkable. This is presumably because the contact (penetration) with the developer which is important in the present invention becomes mild, and the difference between the exposed portion and the unexposed portion is likely to occur. Is done.

  The non-reducing sugar is a saccharide that does not have a free aldehyde group or a ketone group and does not exhibit reducibility, and is a trehalose-type oligosaccharide in which reducing groups are bonded to each other, or a glycoside in which a reducing group and a non-saccharide are bonded to each other. And sugar alcohols reduced by hydrogenation of saccharides and sugars, both of which can be suitably used in the present invention. In the present invention, non-reducing sugars described in JP-A-8-305039 can be preferably used.

  Examples of the trehalose type oligosaccharides include saccharose and trehalose. Examples of the glycoside include alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, zulsiit, allozulcit and the like. . Further, maltitol hydrogenated to disaccharide maltose, reduced form obtained by hydrogenation of oligosaccharide (reduced water candy), and the like are preferable. Among these non-reducing sugars, trehalose-type oligosaccharides and sugar alcohols are preferable, and among them, D-sorbitol, saccharose, reduced syrup, etc. are preferable because they have a buffering action in an appropriate pH region and are inexpensive.

  These non-reducing sugars may be used alone or in combination of two or more. The content of the non-reducing sugar in the non-silicate developer is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass. If the content is less than 0.1% by mass, a sufficient buffering effect tends to be not obtained, and if it exceeds 30% by mass, it is difficult to achieve high concentration and the cost tends to increase.

  Examples of the base used in combination with the non-reducing sugar include conventionally known alkali agents such as inorganic alkali agents and organic alkali agents. Examples of the inorganic alkaline agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, Examples thereof include sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate.

  Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanol. Examples include amine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine.

  The said base may be used individually by 1 type, and may use 2 or more types together. Among these bases, sodium hydroxide and potassium hydroxide are preferable. In the present invention, as the non-silicate developer, a non-reducing sugar alkali metal salt as a main component can be used instead of the non-reducing sugar and the base.

  In addition, an alkaline buffer composed of a weak acid other than the non-reducing sugar and a strong base can be used in combination with the non-silicate developer. The weak acid preferably has a dissociation constant (pKa) of 10.0 to 13.2, and can be selected from, for example, those described in Ionization Constants of Organic Acidsin Aqueous Solution published by Pergmon Press.

  Specifically, alcohols such as 2,2,3,3-tetrafluoropropanol-1, trifluoroethanol and trichloroethanol; aldehydes such as pyridine-2-aldehyde and pyridine-4-aldehyde; salicylic acid 3-hydroxy-2-naphthoic acid, catechol, gallic acid, sulfosalicylic acid, 3,4-dihydroxysulfonic acid, 3,4-dihydroxybenzoic acid, hydroquinone, pyrogallol, o-cresol, m-cresol, p-cresol, Compounds having a phenolic hydroxyl group such as resorsonol; oximes such as acetoxime, 2-hydroxybenzaldehyde oxime, dimethylglyoxime, ethanediamide dioxime, acetophenone oxime; adenosine, inosine, guanine, cytosine, hypoxanthine, chitosan Nucleic acid-related substances such as Nchin; other, diethylaminomethyl acid, benzimidazole, and the like barbituric acid is preferably exemplified.

  Various surfactants and organic solvents can be added to the developer as necessary for the purpose of promoting or suppressing developability, dispersing development residue, or improving ink affinity of the printing plate image area. As the surfactant, anionic, cationic, nonionic and amphoteric surfactants are preferable. Furthermore, in the developer, if necessary, a reducing agent such as sodium salt or potassium salt of inorganic acid such as hydroquinone, resorcin, sulfurous acid, or bisulfite, and further organic carboxylic acid, antifoaming agent, water softener, etc. Can be added.

Furthermore, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer, so that a large amount of developer can be obtained without replacing the developer in the developer tank for a long time. It is known that imaging materials can be processed. This replenishment method is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developer as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving ink affinity of the printing plate image area.
Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Furthermore, reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, organic carboxylic acids, antifoaming agents, and hard water softeners may be added to the developer as necessary. it can.

  The printing plate developed with the developer is post-treated with a desensitizing solution containing washing water, a rinsing solution containing a surfactant and the like, gum arabic and starch derivatives. As the post-treatment of the image forming material of the present invention, these treatments can be used in various combinations.

  In recent years, automatic developing machines for printing plates have been widely used in the plate making and printing industries in order to rationalize and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting the printing plate, each processing liquid tank and a spray device, and each pumped up by a pump while transporting the exposed printing plate horizontally. The processing liquid is sprayed from the spray nozzle and developed. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid. In such automatic processing, each processing solution can be processed while being supplemented with a replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can be applied.

  In the image forming material of the present invention, an image portion unnecessary for a printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, a film edge mark of an original film, etc.) is present. In some cases, the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. As described in JP-A-59-174842, a method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber can also be used.

The printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if a higher printing durability printing plate is desired, a burning treatment is performed as desired. Is given.
In the case of burning a printing plate, the surface-adjusting solution described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655, etc. is used before burning. It is preferable to treat with.
As the method, it is possible to apply on the printing plate with a sponge or absorbent cotton soaked with the surface-adjusting liquid, or by immersing the printing plate in a vat filled with the surface-adjusting liquid, Application by a coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The printing plate coated with the surface-adjusting liquid is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). . In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

  The burned printing plate can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound or the like was used. In some cases, so-called desensitizing treatment such as gumming can be omitted. The printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.

EXAMPLES Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.
-Examples 1-8, Comparative Example 1-
(Production of support)
The support body was produced by processing through the process shown below using a JIS-A-1050 aluminum plate with a thickness of 0.3 mm.

(A) Mechanical surface roughening treatment While supplying a suspension of abrasive (silica sand) having a specific gravity of 1.12 and water as a polishing slurry liquid to a surface of an aluminum plate, it is mechanically rotated by a roller-like nylon brush. Roughening was performed. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was sprayed with an aqueous NaOH solution at a temperature of 70 ° C. (concentration 26 mass%, aluminum ion concentration 6.5 mass%) to carry out an etching treatment, and the aluminum plate was 6 g / m. ² dissolved. Thereafter, washing with water was performed using well water.

(C) Desmut treatment A desmut treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.5 g / liter aqueous solution (aluminum ion 5 g / liter) at a temperature of 50 ° C. The AC power supply waveform is electrochemically roughened using a carbon electrode as the counter electrode, using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero, a DUTY ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Thereafter, washing with water was performed using well water.

(E) Alkali etching treatment The aluminum plate was sprayed at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C. to dissolve the aluminum plate by 0.20 g / m ² , The smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was used was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(F) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water using well water. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Thereafter, washing with water was performed using well water.

(H) Alkaline etching treatment An aluminum plate is etched by spraying at 32 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass, and the aluminum plate is dissolved at 0.10 g / m ² , so The smut component mainly composed of aluminum hydroxide generated during the electrochemical surface roughening treatment was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(I) Desmut treatment A desmut treatment by spraying was performed with a 25% by mass aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by mass of aluminum ions), and then water washing by spraying was performed using well water.

(J) Anodizing treatment As the electrolytic solution, sulfuric acid was used. All electrolytes had a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), and the temperature was 43 ° C. Thereafter, washing with water was performed using well water.
Both current densities were about 30 A / dm ² . The final oxide film amount was 2.7 g / m ² .

・ Support A
The steps (a) to (j) were sequentially performed, and the support A was produced so that the etching amount in the step (e) was 3.4 g / m ² .

・ Support B
A support B was prepared by sequentially performing the steps except for omitting the steps (g), (h), and (i) among the above steps.

・ Support C
A support C was prepared by sequentially performing the steps except that the steps (a), (g), (h), and (i) were omitted.

・ Support D
Except for omitting the process of the above step (a) and (d) (e) (f ) performs the steps in turn, supported as total amount of electricity is 450C / dm ² in step (g) Body D was prepared.
The following supports A, B, C and D were then subjected to the following hydrophilic treatment and undercoating treatment.

(K) Alkali metal silicate treatment An aluminum support obtained by anodizing treatment was immersed in a treatment layer of a 1 mass% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds to immerse the alkali metal silica. Acid salt treatment (silicate treatment) was performed. Then, the water washing by the spray using well water was performed. The amount of silicate adhering at that time was 3.6 mg / m ² .

(Formation of undercoat layer)
On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat layer coating solution having the following composition was applied and dried at 80 ° C. for 15 seconds. The coating amount after drying was 15 mg / m ² .

(Coating solution for undercoat layer)
・ The following polymer compound (I or II) 0.3 g
・ Methanol 100g
・ Water 1g

(Formation of image recording layer)
Next, the lower layer coating solution A having the following composition was applied to the support with the undercoat layer obtained above with a wire bar, and then dried in a drying oven at 140 ° C. for 50 seconds to obtain a coating amount of 0.85 g. / M ² .
Furthermore, the uppermost layer coating liquid B having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 140 ° C. for 60 seconds to obtain image forming materials of Examples 1 to 8 and Comparative Example 1 with a total coating amount of 1.1 g / m ² .
The support used, the polymer compound used for the undercoat layer, and the infrared absorber used for the uppermost layer are shown in Table 1.

(Lower layer coating solution A)
N- (4-aminosulfonylphenyl) methacrylamide /
Acrylonitrile / methyl methacrylate (molar ratio 36:34:30, weight average molecular weight 50,000) 2.13 g
・ Cyanine dye X (the following structure) 0.134 g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.19g
・ 0.008 g of p-toluenesulfonic acid
2-methoxy-4- (N-phenylamino)
Benzenediazonium hexafluorophosphate 0.032 g
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
・ Fluorine-based surfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.023g
・ Γ-butyrolactone 13.16 g
・ Methyl ethyl ketone 25.39g
・ 1-methoxy-2-propanol 12.95 g

(Top layer coating solution B)
-M-cresol / p-cresol novolak resin (molar ratio 60:40, weight average molecular weight 5,000) 0.341 g
-Any of cyanine dyes A to H or X (the following structure) 0.019 g
・ The following structural polymer / MEK 30% solution (the following structure) 0.14 g
・ Quaternary ammonium salt (the following structure) 0.004g
・ Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.004g
・ Fluorosurfactant (Megafac F-781, manufactured by Dainippon Ink & Chemicals, Inc.) 0.001g
・ Methyl ethyl ketone 2.63g
・ 1-methoxy-2-propanol 5.27g

-Comparative Example 2-
Examples 1 to 8 and Comparative Example 1 were applied to a support with an undercoat layer obtained by applying the image recording layer coating liquid C having the following composition with a wire bar, and then using a drying oven at 140 ° C. for 100. The image forming material of Comparative Example 2 was obtained by drying for ² seconds and setting the coating amount to 1.80 g / m ² .

(Coating liquid C for image recording layer)
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (molar ratio 36:34:30, weight average molecular weight 50,000) 0.75 g
-M-cresol / p-cresol novolak resin (molar ratio 60:40, weight average molecular weight 5,000) 0.25 g
・ Tetrahydrophthalic anhydride 0.03g
・ Cyanine dye A (the above structure) 0.017 g
0.015 g of a dye having 1-naphthalenesulfonic acid anion as the counter ion of Victoria Pure Blue BOH
・ Fluorine-based surfactant (Megafac F-177, manufactured by Dainippon Ink & Chemicals, Inc.) 0.05g
・ Γ-Butyrolactone 10g
・ Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

[Evaluation of image forming materials]
Next, performance evaluation of the image forming materials of Examples 1 to 8 and Comparative Examples 1 and 2 was performed. Note that the evaluation test was conducted on the image storage material stored for 14 days at 25 ° C., and the development latitude was further evaluated for the sample stored at the same temperature for 3 months.

(Evaluation of development latitude)
The obtained image forming materials of Examples 1 to 8 and Comparative Examples 1 and 2 were drawn into a test pattern image on a Trendsetter 800 manufactured by Creo under the conditions of a beam intensity of 10.0 W and a drum rotation speed of 250 rpm ( Exposure).
Next, a solution in which carbon dioxide gas was blown into the developer DT-2R manufactured by Fuji Photo Film Co., Ltd. in water (1: 9) until the electrical conductivity reached 37 mS / cm, and a finisher manufactured by Fuji Photo Film Co., Ltd. Using a PS processor LP-940HII manufactured by Fuji Photo Film Co., Ltd., in which a FG-1 aqueous dilution (1: 1) solution was charged, development was performed at a developing temperature of 12 seconds while maintaining the liquid temperature at 30 ° C. Thereafter, an appropriate amount of DT-2R diluted with water (1: 9) was added to the developer, the conductivity was adjusted to 39 mS / cm, and the image forming material in which the test pattern was drawn in the same manner as before was developed. Further, the electrical conductivity was increased by 2 mS / cm, and this operation was continued until a film loss due to image development was observed remarkably.
Of these developed image forming materials, the one developed with each conductivity was checked with a magnifier of 50 times to see if there was any stain or color caused by a poorly developed non-image area residual film, and the image was successfully developed. The conductivity of the developer was determined. Next, the electric conductivity at the limit at which the reduction in the developed film is maintained to such an extent that the printing durability is not substantially affected, specifically, measured using a GRETAG reflection densitometer D196 (manufactured by GretagMacbeth), before development. The critical conductivity was determined such that the reduction in the solid image density after development was within 0.10 relative to the solid image density.
The development latitude was defined as the range between the conductivity of the developer that was successfully developed and the limit conductivity at which the decrease in the developed film was maintained to such an extent that it did not substantially affect printing durability. The larger this value, the wider the development latitude. The results are shown in Table 1.

(Evaluation of sensitivity)
The image forming materials of Examples 1 to 8 and Comparative Examples 1 and 2 were changed to a drum set speed of 250 rpm using a Trend setter 800 manufactured by Creo, and the beam intensity was changed stepwise from 5 W to 15 W, and the test pattern was imaged. I wrote. Thereafter, a PS processor LP940HII manufactured by Fuji Photo Film Co., Ltd., which was charged with a liquid having an electrical conductivity of 45 mS / cm with a water dilution (1: 8) of developer DT-2 manufactured by Fuji Photo Film Co., Ltd. The film was developed at a liquid temperature of 30 ° C. for a development time of 12 seconds. The minimum beam intensity (W) that can develop the non-image area with this developer was measured and used as the sensitivity. A smaller value indicates higher sensitivity. The results are shown in Table 1.

As described above, according to Examples 1 to 8, in the image forming material having the multilayer image recording layer, when the compound having the structure of the general formula (I) is used as the infrared absorber in the uppermost layer, the sensitivity is high.
It can be seen that an image forming material having a wide development latitude and suppressing performance deterioration with time can be obtained.
On the other hand, even in the case of an image forming material having a multi-layer type image recording layer, in the first comparative example using only the infrared absorber not having the structure of the general formula (I) as the uppermost layer, performance deterioration with time was observed. Even in the case where the compound having the structure of the general formula (I) is used, in Comparative Example 2 which is an image forming material having a single-layer type image recording layer, both development latitude and performance deterioration with time are present. It can be seen that it is inferior to the image forming material of the invention.

Claims (1)

A plurality of image recording layers containing a water-insoluble and alkali-soluble resin are provided on a support, and an infrared absorber represented by the following general formula (I) is provided as the uppermost layer among the plurality of image recording layers. An image forming material characterized by that.

In general formula (I), R < ¹ > -R < ⁴ > shows a hydrogen atom, an alkyl group, or an aryl group each independently. R ⁵ and R ⁶ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represent an integer of 0 to 4. R ¹ and R ² , or R ³ and R ⁴ may be bonded to each other to form a ring, and R ¹ and / or R ² and R ⁵ , or R ³ and / or R ⁴ and R ^{6 May} be bonded to each other to form a ring, and when n or m is 2 or more, a plurality of R ⁵ or R ⁶ may be bonded to each other to form a ring. Z ¹ and Z ² each independently represent a hydrogen atom, an alkyl group or an aryl group. Q represents a trimethine group or a pentamethine group, which may have a ring structure formed with a divalent organic group. X ⁻ represents a counter anion.