JP4505388B2 - Image forming material - Google Patents

Description

  The present invention relates to an image forming material, and more specifically, an image forming material suitable for a so-called positive type lithographic printing plate capable of direct plate making, which can be directly made by scanning infrared laser light based on a digital signal of a computer or the like. About.

  In recent years, with the development of image forming technology, 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 directly make a plate without using a film document. It has become. Examples of the plate material used for such direct plate-making include a so-called thermal positive type lithographic printing plate precursor. A thermal positive type lithographic printing plate precursor forms a positive image by causing photothermal conversion in the photosensitive layer by laser light irradiation, thereby causing alkali solubilization of the photosensitive layer. Due to the subtle changes in the intermolecular interaction of the binder in the photosensitive layer, the alkali-soluble discrimination in exposed / unexposed areas is small, and the development latitude (development stability depending on usage conditions) is insufficient. There was a problem of becoming.

Therefore, in order to widen the alkali-soluble development latitude of clear exposed / unexposed portions that can be practically used, the image recording layer is made of a resin having a high alkali solubility (sea portion) and a resin having a low alkali solubility (island portion). There has been proposed an image recording layer that forms a so-called phase separation structure in which a sea-island structure is formed (see, for example, Patent Document 1).
However, an image forming material in which such an image recording layer has a phase separation structure has insufficient film strength of the image recording layer itself, and improvement has been desired.

  Further, for the purpose of improving the contrast between the exposed area and the unexposed area, a positive lithographic printing plate having a photosensitive layer containing a specific phenolic resin and an acid color-forming dye has been proposed (for example, a patent). Reference 2). Such a photosensitive composition is advantageous in that it has excellent alkali development resistance due to the interaction between the dye and the phenolic resin, and also contains a sufficient amount of the dye, so that the plate inspection of the photosensitive layer is also excellent. In addition, when a sufficient amount is added to develop the alkali developer resistance improving effect, there is a problem that the developability of the exposed area tends to be lowered.

  The positive lithographic printing plate material for infrared lasers must be a resin that is highly soluble in an alkaline developer as a binder resin, compared to positive lithographic printing plate materials that are made by UV exposure. There is also a problem that the resistance to the plate cleaner used is low and the photosensitive composition is eluted when the plate surface is wiped with the cleaner.

In order to improve such cleaner resistance and printing durability, a technique using a polymer having a urea bond in a side chain has been proposed (for example, see Patent Document 3). Although the effect of improving the printing durability of the unexposed area can be obtained by using this polymer, further improvement is desired practically, and from the viewpoint of developability of the exposed area, it is still improved in terms of improving discrimination. There was room for.
JP 11-44956 A JP-A-11-190903 JP 2000-330265 A

  The present invention has been made to overcome the drawbacks of the prior art, and it is an object of the present invention to achieve the following objects. That is, an object of the present invention is to provide an image forming material which is useful as a positive lithographic printing plate precursor for an infrared laser having a wide development latitude and excellent printing durability and chemical resistance of an image area. To do.

As a result of the study, the present inventors have found that the above object can be achieved by containing a specific two kinds of alkali-soluble resins in a specific ratio in the image recording layer and forming a dispersed phase by one of them. It came to be completed.
That is, the image forming material of the present invention contains (A) an alkali-soluble resin having a urea bond in the side chain, (B) an alkali-soluble resin having a phenolic hydroxyl group, and (C) a photothermal conversion agent on the support. The weight ratio of (A) the alkali-soluble resin having a urea bond to the side chain and (B) the alkali-soluble resin having a phenolic hydroxyl group is in the range of 6: 1 to 19: 1. In the image recording layer, (A) an alkali-soluble resin having a urea bond in the side chain and (B) an alkali-soluble resin having a phenolic hydroxyl group form a phase separation structure.

The phase separation structure in the image recording layer is (A) a sea-island structure in which an alkali-soluble resin having a urea bond in the side chain forms a dispersion medium, and (B) an alkali-soluble resin having a phenolic hydroxyl group forms a dispersed phase. It is preferable.
The weight ratio of (A) the alkali-soluble resin having a urea bond in the side chain and (B) the alkali-soluble resin having a phenolic hydroxyl group contained in the image recording layer is preferably in the range of 8: 1 to 19: 1. is there.
Of these two types of alkali-soluble resins, (A) the dissolution rate of an alkali-soluble resin having a urea bond in the side chain, which forms a dispersion medium, in an alkaline developer forms a dispersed phase. (B) a phenolic hydroxyl group It is a preferable aspect that it is 2 times or more of the dissolution rate with respect to the alkaline developing solution of alkali-soluble resin which has this.

Although the operation of the present invention is not clear, it is presumed as follows.
That is, the image recording layer in the present invention contains the two types of alkali-soluble resins (A) and (B) in a specific blend ratio, and a phase separation structure by these two types of alkali-soluble resins, One of the features is that a disperse phase is formed by at least one type and a dispersion medium (matrix phase) is formed by the other type to form a sea-island structure as a phase separation structure. When the (C) photothermal conversion agent is added to the image recording layer having such a structure, the photothermal conversion agent is unevenly distributed in either the dispersed phase or the matrix phase of the phase separation structure, but particularly forms a dispersed phase. There is a tendency to be unevenly distributed in the specific polymer B. The disperse phase in which the photothermal conversion agent is unevenly distributed tends to deteriorate in developability due to its structure, but in the exposed portion, photothermal conversion is efficiently performed in this portion, and heat is generated intensively. It is considered that the interaction forming the recording layer is quickly released, and the dissolution inhibiting action is released with high sensitivity. In addition, since the photothermal conversion agent is unevenly distributed in the dispersed phase, the developability in the matrix phase does not deteriorate, and the image recording layer is quickly removed together with the dispersed phase due to the excellent alkali developer solubility of the alkali-soluble resin. Thus, it is considered that alkali developability can be improved.
On the other hand, in the unexposed area, the photothermal conversion agent is unevenly distributed, and the fine dispersed phase with reduced developability is uniformly dispersed in the matrix phase. As a result, in the present invention, the image recording layer exhibits excellent alkali developer resistance in the unexposed area and chemical resistance inherent in the specific polymer A. In the exposed area, photothermal conversion occurs. It is presumed that the decrease in the developability due to the agent is suppressed, and the excellent solubility in the alkaline developer is exhibited, so that the discrimination is increased and the development latitude is expanded.

  According to the present invention, it is possible to provide an image forming material useful as a positive planographic printing plate precursor for an infrared laser having a wide development latitude and excellent printing durability and chemical resistance of an image area.

The present invention will be described in detail.
The image-forming material of the present invention comprises, on a support, (A) an alkali-soluble resin having a urea bond in the side chain (hereinafter appropriately referred to as a specific polymer A), and (B) an alkali-soluble resin having a phenolic hydroxyl group ( (Hereinafter referred to as a specific polymer B) and (C) an image recording layer containing a photothermal conversion agent, (A) an alkali-soluble resin having a urea bond in the side chain, and (B) a phenolic hydroxyl group The weight ratio to the alkali-soluble resin is in the range of 6: 1 to 19: 1, and (A) the alkali-soluble resin having a urea bond in the side chain and (B) the phenolic hydroxyl group in the image recording layer. The alkali-soluble resin has a phase separation structure.
Hereinafter, the components of the present invention will be described in detail. First, the alkali-soluble resin having a urea bond in the side chain (A), which is a characteristic component of the present invention, will be described.

[(A) Polymer having urea bond in side chain (specific polymer A)]
The (A) specific polymer used in the present invention is not particularly limited as long as it is a polymer having a urea bond in the side chain, but among them, it is preferable to use a polymer that is insoluble in water and soluble in an alkaline aqueous solution. As such a polymer, a known polymer can be used. In particular, from the viewpoint of chemical resistance when printing using a printing chemical, a vinyl polymerization system or a condensation polymerization having a structural unit represented by any one of the following general formulas (1-a) to (1-c) Particularly preferred are high molecular weight compounds or novolak resins having a urea bond in the side chain. Furthermore, it is preferable from the viewpoint of improving sensitivity that the side chain has a functional group that contributes to solubility in an alkaline aqueous solution in addition to the urea bond.

In the general formulas (1-a) to (1-c), R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a carboxy group, or a salt thereof. R ³ represents a hydrogen atom, a halogen atom, an alkyl group or an aryl group. X represents a divalent linking group, and an alkylene group or a phenylene group which may have a substituent, for example, is preferable. Y represents a divalent aromatic group that may have a substituent, and examples thereof include a phenylene group or a naphthylene group that may have a substituent.

The content of the structural unit represented by any one of the general formulas (1-a) to (1-c) in the specific polymer (A) is a copolymer contained in a charge ratio of 10 to 80 mol%. It is preferably 15 to 70 mol%, more preferably 20 to 60 mol%.
When the content is less than 10 mol%, the chemical resistance is poor, and when it exceeds 80 mol%, the solubility in an alkaline aqueous solution is low and the sensitivity may be low.

  There is no restriction | limiting in particular as a manufacturing method of the high molecular compound which has a structural unit represented by either of the said general formula (1-a)-(1-c), It can manufacture by a well-known various method. Examples thereof include a method of polymerizing a polymerizable monomer in a solvent using a polymerization initiator.

  In the method of polymerizing the polymerizable monomer in a solvent using a polymerization initiator, the polymerizable monomer includes one or more urea bonds and one or more polymerizable unsaturated groups in one molecule. Preferred examples include a compound having a bond, such as a compound represented by the following general formula (1-d).

In the general formula (1-d), R ⁴ represents a hydrogen atom or an alkyl group. X represents a divalent linking group, and examples thereof include an alkylene group or a phenylene group which may have a substituent. Y represents a divalent aromatic group which may have a substituent, and examples thereof include a phenylene group or a naphthylene group which may have a substituent.

  Examples of the compound represented by the general formula (1-d) include 1- (N ′-(4-hydroxyphenyl) ureido) methyl acrylate and 1- (N ′-(3-hydroxyphenyl) ureido) methyl. Acrylate, 1- (N ′-(2-hydroxyphenyl) ureido) methyl acrylate, 1- (N ′-(3-hydroxy-4-methylphenyl) ureido) methyl acrylate, 1- (N ′-(2-hydroxy) -5-methylphenyl) ureido) methyl acrylate, 1- (N '-(5-hydroxynaphthyl) ureido) methyl acrylate, 1- (N'-(2-hydroxy-5-phenylphenyl) ureido) methyl acrylate, 2 -(N '-(4-hydroxyphenyl) ureido) ethyl acrylate, 2- (N'-(3-hydroxyphenyl) uree De) ethyl acrylate, 2- (N ′-(2-hydroxyphenyl) ureido) ethyl acrylate, 2- (N ′-(3-hydroxy-4-methylphenyl) ureido) ethyl acrylate, 2- (N ′-( 2-hydroxy-5-methylphenyl) ureido) ethyl acrylate, 2- (N ′-(5-hydroxynaphthyl) ureido) ethyl acrylate, 2- (N ′-(2-hydroxy-5-phenylphenyl) ureido) ethyl Acrylate, 4- (N ′-(4-hydroxyphenyl) ureido) butyl acrylate, 4- (N ′-(3-hydroxyphenyl) ureido) butyl acrylate, 4- (N ′-(2-hydroxyphenyl) ureido) Butyl acrylate, 4- (N ′-(3-hydroxy-4-methylphenyl) ureido) butyl acrylate 4- (N ′-(2-hydroxy-5-methylphenyl) ureido) butyl acrylate, 4- (N ′-(5-hydroxynaphthyl) ureido) butyl acrylate, 4- (N ′-(2-hydroxy) Acrylate derivatives such as -5-phenylphenyl) ureido) butyl acrylate: 1- (N '-(4-hydroxyphenyl) ureido) methyl methacrylate, 1- (N'-(3-hydroxyphenyl) ureido) methyl methacrylate, 1 -(N '-(2-hydroxyphenyl) ureido) methyl methacrylate, 1- (N'-(3-hydroxy-4-methylphenyl) ureido) methyl methacrylate, 1- (N '-(2-hydroxy-5- Methylphenyl) ureido) methyl methacrylate, 1- (N ′-(5-hydroxynaphthyl) ure Id) methyl methacrylate, 1- (N ′-(2-hydroxy-5-phenylphenyl) ureido) methyl methacrylate, 2- (N ′-(4-hydroxyphenyl) ureido) ethyl methacrylate, 2- (N ′-( 3-hydroxyphenyl) ureido) ethyl methacrylate, 2- (N ′-(2-hydroxyphenyl) ureido) ethyl methacrylate, 2- (N ′-(3-hydroxy-4-methylphenyl) ureido) ethyl methacrylate, 2- (N ′-(2-hydroxy-5-methylphenyl) ureido) ethyl methacrylate, 2- (N ′-(5-hydroxynaphthyl) ureido) ethyl methacrylate, 2- (N ′-(2-hydroxy-5-phenyl) Phenyl) ureido) ethyl methacrylate, 4- (N ′-(4-hydroxyphenyl) Raid) butyl methacrylate, 4- (N ′-(3-hydroxyphenyl) ureido) butyl methacrylate, 4- (N ′-(2-hydroxyphenyl) ureido) butyl methacrylate, 4- (N ′-(3-hydroxy-) 4-methylphenyl) ureido) butyl methacrylate, 4- (N ′-(2-hydroxy-5-methylphenyl) ureido) butyl methacrylate, 4- (N ′-(5-hydroxynaphthyl) ureido) butyl methacrylate, 4- And methacrylate derivatives such as (N ′-(2-hydroxy-5-phenylphenyl) ureido) butyl methacrylate. These may be used individually by 1 type and may use 2 or more types together.

Since the polymerizable monomer has characteristic absorption at 1600 to 1700 cm ⁻¹ of an infrared absorption spectrum based on a urea bond, it can be identified by measuring the infrared absorption spectrum. Moreover, identification by melting | fusing point, proton NMR, etc. is also possible.
For example, in the above specific examples, 2- (N ′-(4-hydroxyphenyl) ureido) ethyl methacrylate has a melting point of 131 to 133 ° C. and can be identified from the absorption of the IR spectrum based on the hydroxyl group and the urea bond. is there.

  In addition to the compound represented by the general formula (1-d), for example, 2- (N ′-(4-carboxylphenyl) ureido) ethyl acrylate, 2- (N ′-(4-sulfamoyl) Phenyl) ureido) ethyl acrylate, 2- (N ′-(4-sulfophenyl) ureido) ethyl acrylate, 2- (N ′-(4-phosphonophenyl) ureido) ethyl acrylate and other acrylates having acidic groups Class: 2- (N ′-(4-carboxylphenyl) ureido) ethyl methacrylate, 2- (N ′-(4-sulfamoylphenyl) ureido) ethyl methacrylate, 2- (N ′-(4-sulfophenyl) Meta having acidic groups such as ureido) ethyl methacrylate, 2- (N ′-(4-phosphonophenyl) ureido) ethyl methacrylate Relates: 2- (N′-methylureido) ethyl acrylate, 2- (N′-propylureido) ethyl acrylate, 2- (N′-phenylureido) ethyl acrylate, 2- (N ′-(4-methylphenyl) ) Ureido) ethyl acrylate, 2- (N ′-(2-methylphenyl) ureido) ethyl acrylate, 2- (N′-naphthylureido) ethyl acrylate, 2- (N ′-(2-phenylphenyl) ureido) ethyl Acrylates having no acidic group such as acrylate: 2- (N′-methylureido) ethyl methacrylate, 2- (N′-propylureido) ethyl methacrylate, 2- (N′-phenylureido) ethyl methacrylate 2- (N ′-(4-methylphenyl) ureido) ethyl methacrylate, 2- (N ′-( 2-methylphenyl) ureido) ethyl methacrylate, 2- (N′-naphthylureido) ethyl methacrylate, 2- (N ′-(2-phenylphenyl) ureido) ethyl methacrylate and other methacrylates having no acidic group Preferred examples thereof include polymerizable monomers.

  Among the specific examples described above, 2- (N ′-(4-carboxyphenyl) ureido) ethyl methacrylate has a decomposition temperature of 220 ° C. and can be identified from absorption of IR spectrum based on the carboxy group and the urea bond.

  There is no restriction | limiting in particular about the manufacturing method of the said polymerizable monomer, For example, the amine compound represented by the following general formula (1-e), the amine compound represented by the following general formula (1-f), and A known production method in which is reacted is preferably used.

In the general formula (1-e), R ⁵ represents a hydrogen atom or an alkyl group. X is the same as in the general formula (1-d). In General Formula (1-f), R ⁶ represents a hydrogen atom or an alkyl group that may have a substituent. Y is the same as in the general formula (1-d). Z represents a hydroxyl group, a carboxy group, or a sulfonamide group.

In the production method, the compound represented by the general formula (1-e) and the compound represented by the general formula (1-f) in which Z is a hydroxyl group and R ⁶ is a hydrogen atom are used. The polymerizable monomer represented by 1-d) can be suitably obtained.

In the said manufacturing method, since the amino group in General formula (1-f) has high activity with respect to an isocyanate group compared with a hydroxyl group, a carboxy group, or -NH-CO- group etc., the said general formula (1- A polysynthetic monomer represented by d) can be obtained.
Further, if desired, the amine compound represented by the general formula (1-f) is excessively added, and the isocyanate compound represented by the general formula (1-e) is gradually added to the amine compound. The reaction can proceed.

  The solvent is not particularly limited as long as it is a known organic solvent, and examples thereof preferably include those having no active hydrogen atom, such as ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether. , Ethylene glycol monoethyl ether, 2-methoxyethyl acetate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-methoxy-2-propanol acetate, 1-methoxy-2-propyl acetate, 1-ethoxy Examples include 2-propyl acetate, dimethyl sulfoxide, toluene, ethyl acetate, methyl lactate, ethyl lactate, and dioxane. These may be used individually by 1 type and may use 2 or more types together.

The reaction time may be performed until the isocyanate compound represented by the general formula (1-e) disappears or until the amount of urea bond becomes a constant amount, and is usually 15 minutes to 24 hours. is there.
Moreover, as the temperature of the said reaction, 0-40 degreeC is preferable.

  The polymerizable monomer may be diluted with dilute hydrochloric acid for the purpose of removing unreacted raw material components and by-products when reacted with an excess of the amine compound represented by the general formula (1-f). It can be made highly pure by neutralizing with an acidic compound such as the above to form a salt of the amine compound represented by the general formula (1-f), followed by washing with water, filtration, and vacuum drying.

  The specific polymer (A) according to the present invention is a single polymerizable monomer containing the urea bond (for example, the monomers represented by the general formulas (1-a) to (1-c)). It may be a polymer or two or more kinds of copolymers, but it should be a copolymer with a compound having one or more polymerizable unsaturated bonds and not containing urea bonds. From the viewpoint of The copolymer may have any structure such as a block body, a random body, or a graft body.

  The copolymer is composed of 100% by mole of the polymerizable monomer and 100% by mole of the total amount of the polymerizable monomer and the compound having at least one polymerizable unsaturated bond and no urea bond. Those obtained by copolymerizing 10 to 80 mol% of the body are preferred.

  Examples of the compound having at least one polymerizable unsaturated bond and not containing a urea bond include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, ethyl hexyl acrylate, Octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate, methoxybenzyl acrylate Acrylates such as tetrahydroacrylate: aryl acrylates such as phenyl acrylate and furfuryl acrylate: methyl methacrylate, ethyl Tacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, Methacrylic acid esters such as trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate: aryl methacrylates such as phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate: acrylamide As derivatives thereof, N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, Nt-butylacrylamide, N-heptylacrylamide, N-octylacrylamide, N-cyclohexylacrylamide, N- N-alkyl acrylamides such as benzyl acrylamide: N-phenyl acrylamide, N-tolyl acrylamide, N-nitrophenyl acrylamide, N-naphthyl acrylamide, N-aryl acrylamides such as N-hydroxyphenyl acrylamide: N, N-dimethyl acrylamide N, N-diethylacrylamide, N, N-dibutylacrylamide, N, N-dibutylacrylamide, N, N-diisobutylacrylamide, N, -N, N-dialkylacrylamides such as diethylhexylacrylamide and N, N-dicyclohexylacrylamide: N-methyl-N-phenylacrylamide, N-hydroxyethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetyl N, N-arylacrylamides such as acrylamide: methacrylamide or derivatives thereof include N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-butylmethacrylamide, Nt-butylmethacrylamide, N-alkyl methacrylamides such as N-ethylhexyl methacrylamide, N-hydroxyethyl methacrylamide, N-cyclohexyl methacrylamide:

N-aryl methacrylamides such as N-phenylmethacrylamide and N-naphthylmethacrylamide: N, N- such as N, N-diethylmethacrylamide, N, N-dipropylmethacrylamide and N, N-dibutylmethacrylamide Dialkylmethacrylamides: N, N-diarylmethacrylamides such as N, N-diphenylmethacrylamide: N-hydroxyethyl-N-methylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-ethyl-N- Methacrylamide derivatives such as phenylmethacrylamide: ants such as allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, allyloxyethanol Compounds: hexyl vinyl ether, octyl vinyl ether, dodecyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol Vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl Vinyl ethers such as luanthranyl ether: vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valate, vinyl caproate, vinyl chloroacetate, vinyl methoxyacetate, vinyl butoxy acetate, vinyl phenyl acetate, vinyl Vinyl esters such as acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexylcarboxylate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate:

Methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, cyclohexyl styrene, dodecyl styrene, benzyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, Methoxystyrene, 4-methoxy-3-methylstyrene, dimethoxystyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, 2-bromo-4- Styrenes such as trifluoromethylstyrene and 4-fluoro-3-trifluoromethylstyrene: butyl crotonic acid, Crotonic acid esters such as hexyl rotonic acid, crotonic acid, glycerin monocrotonate: dimethyl itaconate, diethyl itaconate, dialkyl itaconates such as dibutyl itaconate: maleic acid such as dimethyl malate, dibutyl fumarate or fumaric acid Dialkyls of: maleimide, N-phenylmaleimide, N-2-methylphenylmaleimide, N-2,6-diethylphenylmaleimide, N-2-chlorophenylmaleimide, N-cyclohexylmaleimide, N-laurylmaleimide, N-hydroxyphenyl Maleimides such as maleimide: Other examples include N-vinylpyrrolidone, N-vinylpyridine, acrylonitrile, methacrylonitrile and the like. These compounds may be used individually by 1 type, and may use 2 or more types together.

  Of these compounds, (meth) acrylic acid esters, (meth) acrylamides, maleimides, and (meth) acrylonitriles are particularly preferable.

  In addition, in this specification, when referring to both or one of acrylate and methacrylate, it may be described as (meth) acrylate. Similarly, acrylic acid and / or methacrylic acid or both of (meth) acrylic acid, acrylonitrile and / or methacrylonitrile or both (meth) acrylonitrile and / or acrylamide and / or methacrylamide (meth) ) Sometimes referred to as acrylamide.

  Hereinafter, preferred examples of the specific polymer A according to the present invention will be given together with the weight average molecular weight (Mw) and the number average molecular weight (Mn) depending on the structural unit and the polymerization molar ratio, but the present invention is limited to these. is not.

  The molecular weight of the specific polymer (A) according to the present invention is preferably 2000 or more, more preferably 3000 to 500,000 in terms of weight average molecular weight. Moreover, in number average molecular weight, 1000 or more are preferable and 2000-400,000 are more preferable.

  The content of the (A) specific polymer A in the image recording layer according to the present invention is preferably 50 to 94% by mass, and 70 to 90% by mass with respect to the total solid content of the composition constituting the image recording layer. Is more preferable, and it is more preferable that it is 75-90 mass%.

[(B) Alkali-soluble resin having a phenolic hydroxyl group (specific polymer B)]
The image recording layer in the invention contains at least two types of alkali-soluble resins, the specific polymer A and the specific polymer B, and forms a phase separation structure resulting from the two types of alkali-soluble resins. It is characterized by that.
In order to form a phase separation structure, preferably a sea-island structure composed of a dispersed phase and a matrix phase, in the image recording layer, the alkali-soluble resin serving as the dispersed phase and the dispersion medium (matrix phase) are not compatible with each other. Is a condition. In the present invention, for the specific polymer A, an alkali-soluble resin having a phenolic hydroxyl group is selected as a polymer that satisfies this condition and is suitable for forming a positive image recording layer.

The preferred specific polymer B used in the present invention is not particularly limited as long as it has a phenolic hydroxyl group represented by the following (1) in its structure and is soluble in an alkaline developer.
(1) Phenolic hydroxyl group (-Ar-OH)
(Ar represents a divalent aryl linking group which may have a substituent.)

Preferred examples of the specific polymer B include novolak resins, xylenol resins, and resole resins. Among these, novolak resins and xylenol resins are more preferable, and phenol formaldehyde resins, m-cresol formaldehyde resins, and p-cresol formaldehyde resins are particularly preferable. , M- / p-mixed cresol formaldehyde resin, phenol / cresol (any of m-, p-, o-, m- / p-mix, m- / o-mix and o- / p-mix) Mixed formaldehyde resin, 1,2-xylenol, 1,3-xylenol, 1,4-xylenol, 1,5-xylenol, 2,3-xylenol, 2,4-xylenol resin, xylenol / phenol mixed resin, xylenol / novolak Mixed resin, xylenol Novolak / phenol mixed resin, and the like.
Further, acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, hydroxystyrene or the like having a phenolic hydroxyl group can also be used.
These may be used alone or in combination of two or more.

  As the above-mentioned phenolic resin, those having a weight average molecular weight of 1,500 or more and a number average molecular weight of 300 or more are preferable from the viewpoint of image forming properties. More preferably, the weight average molecular weight is 3,000 to 300,000, the number average molecular weight is 500 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .

  A preferable content of (B) the specific polymer B in the image recording layer according to the present invention is 2 to 14% by mass and 2 to 10% by mass with respect to the total solid content of the composition constituting the image recording layer. More preferably, it is more preferable that it is 5-10 mass%.

-Phase composition-
As described above, the image recording layer in the present invention has a configuration in which the specific polymer B forms a dispersed phase among the two types of alkali-soluble resins (A) and (B) contained therein, that is, alkali dissolution. A so-called phase separation structure is formed in which a highly soluble resin (sea portion) and a low alkali-soluble resin (island portion) form a sea-island structure. The details of such a phase separation structure are, for example, as described in JP-A-11-44956.
The phase-separated structure (sea-island structure) can be formed by using a combination of at least two types of resins that are compatible with each other and do not form a homogeneous phase. In this case, an alkali-soluble resin (specific polymer) that constitutes the dispersion medium. A preferred blend ratio (weight ratio) between the A) and the alkali-soluble resin (specific polymer B) constituting the dispersed phase is 6: 1 to 19: 1 from the viewpoint of sea-island structure formation, and a more preferred blend ratio. Is 8: 1 to 19: 1.
The (C) photothermal conversion agent described in detail below is contained unevenly in the specific polymer B among the two alkali-soluble resins when forming the image recording layer, and is contained in a large amount in the dispersed phase having a phase separation structure. .

Further, from the viewpoint that the advantages of such a phase separation structure are sufficiently expressed, the dissolution rate of an alkali-soluble resin having a urea bond in the side chain (A) forming the sea (dispersion medium) in an alkaline developer is high. The dissolution rate of the alkali-soluble resin having a phenolic hydroxyl group (B) that forms an island (dispersed phase) in an alkaline developer is preferably twice or more.
At this time, the dissolution rate in the alkaline developer can be measured by the method described below. The comparison of the dissolution rates is performed based on values measured under the same conditions using the same alkaline developer for each of the specific polymer A and the specific polymer B.
The dissolution rate in the present invention employs a value obtained by the following measurement method.
A polyethylene terephthalate (PET) sheet is used as a base material, and a sample polymer is dissolved on an organic solvent suitable for the polymer on the surface, followed by coating and drying. The solution concentration and the like are adjusted so that the coating amount after drying is 4 g / m ² . The polymer film coated on the PET substrate is immersed in a 3.5 wt% potassium silicate aqueous solution (SiO ₂ / K ₂ O molar ratio: 1.16) at 25 ° C. for different times and washed with water. The soaking speed is determined by the soaking time that the film is not dissolved.

(Other alkali-soluble resins)
In the image recording layer of the present invention, alkali-soluble resins other than the two types of alkali-soluble resins can be used as long as the effects of the present invention are not impaired. Examples of such alkali-soluble resins include resins having the acidic groups listed in the following (2) to (6) in the main chain and / or side chain of the polymer.

(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 said (2)-(6), R represents the hydrocarbon group which may have a hydrogen atom or a substituent.

  Among the alkali-soluble resins having an acidic group selected from (2) to (6) above, (2) a sulfonamide group and (3) an alkali-soluble resin having an active imide group are preferable, and in particular, (2) a sulfonamide group. Alkali-soluble resins having the above are preferable as a combination component 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 (2)-(6), the following can be mentioned, for example.
(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 the compound as described above include compounds 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 them, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule is preferable. For example, the following general formula (i) to general formula ( and a compound represented by v).

In the general formulas (i) to (v), X ¹ and X ² each independently represent —O— or —NR ⁷ . R ¹ and R ⁴ each independently represents a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² , and R ¹⁶ each independently represent an optionally substituted alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, an arylene group, or an aralkylene group. . R ³ , R ⁷ , and R ¹³ 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 ⁶ and R ¹⁷ each independently represents a C 1-12 alkyl group, cycloalkyl group, aryl group or aralkyl group which may have a substituent. R ⁸ , R ¹⁰ and R ¹⁴ each independently represent a hydrogen atom or —CH ₃ . R ¹¹ and R ¹⁵ each independently represents a single bond or a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a substituent. Y ¹ and Y ² each independently represent a single bond or CO.

  Among the compounds represented by the general formula (i) to the general formula (v), examples of the alkali-soluble resin that can be used in the present invention include 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 the compound as described above include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule.

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

  The minimum structural unit having an acidic group selected from the above (2) to (6) is not particularly limited to one kind, and two or more minimum structural units having the same acidic group or different acidic groups are included. What copolymerized 2 or more types of minimum structural units can also be used.

  The alkali-soluble resin that can be used in the present invention is preferably a (co) polymer containing 10 mol% or more of a compound having an acidic group selected from (2) to (6), and such an acidic group is contained in an amount of 20 mol% or more. The inclusion is more preferable. If it is less than 10 mol%, the development latitude tends to be insufficiently improved.

  As the monomer component to be copolymerized with the polymerizable monomer having an acidic group represented by the above (2) to (6) (having no thousand centuries), for example, the monomers listed in the following (m1) to (m12) are used. However, it 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 polymerizable monomer having a phenolic hydroxyl group or a homopolymer or copolymer of a polymerizable monomer having an active imide group, and particularly m-aminosulfonylphenyl methacrylate, N- ( A homopolymer or copolymer of a polymerizable monomer having a sulfonamide group such as p-aminosulfonylphenyl) methacrylamide or N- (p-aminosulfonylphenyl) acrylamide is preferred. The weight average molecular weight is preferably 2,000 or more and the number average molecular weight is 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. .

  In addition, the recording layer needs to contain a specific polymer A, a specific polymer B, which are essential components, and a resin capable of forming at least two kinds of phase-separated structures used together as desired. The total addition amount is 30 to 99% by mass, preferably 40 to 95% by mass, and particularly preferably 50 to 90% by mass in the total solid content of the image recording layer. When the addition amount of the alkali-soluble resin is less than 30% by mass, the durability of the image recording layer deteriorates. When the addition amount exceeds 99% by mass, the addition amount of “(C) photothermal conversion agent” described later decreases. Sensitivity decreases, which is not preferable.

[(C) Photothermal conversion agent]
The image recording layer according to the present invention includes an object-to-light heat conversion agent that has absorption at an exposure wavelength and exhibits light / heat conversion ability by light in this wavelength range. Generally, various infrared absorbing dyes or infrared absorbing pigments having a light absorption region in the infrared region of 700 nm or more, preferably 750 to 1200 nm, and absorbing light in the wavelength region within this range to generate heat can be used. .

  As the dye, commercially available dyes, for example, known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, Examples thereof include oxonol dyes, diimonium dyes, aminium dyes, and croconium dyes.

  Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59- 48187, JP-A 59-73996, JP-A 60-52940, JP-A 60-63744, etc., naphthoquinone dyes, JP-A 58-112792, etc. And cyanine dyes described in British Patent 434,875.

  Further, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used, and substituted arylbenzo (thio) pyrylium salts described in US Pat. No. 3,881,924 Trimethine thiapyrylium salts described in JP-A Nos. 57-142645 (US Pat. No. 4,327,169), JP-A Nos. 58-181051, 58-220143, 59-41363, 59- 84248, 59-84249, 59-146063, 59-146061, pyrylium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 And the pyrylium compounds disclosed in JP-B-5-13514 and JP-A-5-19702 are also preferably used. .

  Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Furthermore, the dyes represented by the following general formulas (a) to (e) are preferable because they are excellent in photothermal conversion efficiency. In particular, the cyanine dyes represented by the following general formula (a) are used in the image forming material of the present invention. In this case, it is most preferable because it gives a high interaction with the alkali-soluble resin and is excellent in stability and economy.

In formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a carbon atom having 1 to 12 carbon atoms including a hetero atom. Indicates a hydrogen group. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.

In the above formula, Xa ^- has Za described later ^- is defined as for, Ra represents a hydrogen atom, an alkyl group, ant - represents a group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom . R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring. Alternatively, it is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in the structure and charge neutralization is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, from the storage stability of the image recording layer coating solution. Hexafluorophosphate ion and aryl sulfonate ion.

  Specific examples of the cyanine dye represented by formula (a) that can be preferably used in the present invention include those exemplified below, and paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. And those described in paragraph numbers [0012] to [0038] of JP-A No. 2002-40638 and paragraph numbers [0012] to [0023] of JP-A No. 2002-23360.

In the general formula (b), L represents a methine chain having 7 or more conjugated carbon atoms, the methine chain may have a substituent, and the substituents may be bonded to each other to form a ring structure. Good. Zb ⁺ represents a counter cation. Preferred counter cations include ammonium, iodonium, sulfonium, phosphonium, pyridinium, alkali metal cations (Na ⁺ , K ⁺ , Li ⁺ ) and the like. R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ are each independently a hydrogen atom or halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, carbonyl group, thio group, sulfonyl group, sulfinyl group, This represents a substituent selected from an oxy group or an amino group, or a combination of two or three of these, and may be bonded to each other to form a ring structure. Here, in general formula (b), those in which L represents a methine chain having 7 conjugated carbon atoms and those in which R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ all represent hydrogen atoms are easily available. It is preferable from the viewpoint of effect.

  Specific examples of the dye represented by formula (b) that can be suitably used in the present invention include those exemplified below.

In general formula (c), Y ³ and Y ⁴ each represent an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. M represents a methine chain having 5 or more conjugated carbon atoms. R ^{21 to} R ²⁴ and R ^{25 to} R ²⁸ may be the same or different, and are a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group. Represents a thio group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. Further, wherein Za ^- include a counter anion, Za in the general formula (a) ^- it is synonymous.

  In the present invention, specific examples of the dye represented by formula (c) that can be suitably used include those exemplified below.

In general formula (d), R ²⁹ to R ³¹ each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ³³ and R ³⁴ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represents an integer of 0 to 4. R ²⁹ and R ³⁰ , or R ³¹ and R ³² may be bonded to each other to form a ring, and R ²⁹ and / or R ³⁰ is R ³³ and R ³¹ and / or R ³² is R ³⁴ A ring may be bonded to each other, and when there are a plurality of R ³³ or R ³⁴ , R ³³ or R ³⁴ may be bonded to each other to form a ring. X ² and X ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group, and at least one of X ² and X ³ represents a hydrogen atom or an alkyl group. Q is a trimethine group or a pentamethine group which may have a substituent, and may form a ring structure together with a divalent organic group. Zc ⁻ represents a counter anion and has the same meaning as Za ⁻ in the general formula (a).

  In the present invention, specific examples of the dye represented by the general formula (d) that can be suitably used include those exemplified below.

In general formula (e), R ^{35 to} R ⁵⁰ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxyl group, which may have a substituent, A carbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxy group, an amino group, and an onium salt structure are shown. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein include IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements can be mentioned, among which copper, magnesium, iron, zinc, cobalt, aluminum, titanium, and vanadium are preferable.

  In the present invention, specific examples of the dye represented by formula (e) that can be suitably used include those exemplified below.

  Examples of the pigment include commercially available pigments or color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technical Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), and The pigments described in “Printing Ink Technology” published by CMC (published in 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-bonded 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, isotopic pigments Indolinone pigments, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, and carbon black can be used.

  These pigments may be used without surface treatment or may be used after surface treatment. As the surface treatment method, a method of surface coating of resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate) to the pigment surface Etc. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle diameter of the pigment is preferably in the range of 0.01 μm to 10 μm, and preferably in the range of 0.05 μm to 1 μm, from the viewpoint of the stability of the dispersion in the coating liquid and the uniformity of the image recording layer. More preferably, it is preferably in the range of 0.1 μm to 1 μm.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Dispersers include ultrasonic dispersers, sand mills, attritors, par mills, super mills, ball mills, impellers, desperzers, KD mills, colloid mills, Dynatrons, three-rollers Lumil, pressure kneader and the like. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  These photothermal conversion agents are 0.01 to 50% by mass, preferably 0.1%, based on the total solid content constituting the image recording layer, from the viewpoint of balance between sensitivity and uniformity and durability of the image recording layer. In the case of a dye, particularly preferably in the case of a dye, 0.5 to 10% by mass, and particularly in the case of a pigment, it can be added in a proportion of preferably 0.1 to 10% by mass.

[Other ingredients]
Various additives can be further added to the image recording layer as necessary.
For example, in order to adjust the solubility of the image recording layer, when other onium salts, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, polyfunctional amine compounds, etc. are added, an alkali water-soluble polymer (alkali-soluble resin) is added. It is preferable to add a so-called dissolution inhibitor that improves the dissolution inhibiting function in the developer. Among them, an onium salt, an o-quinonediazide compound, a sulfonic acid alkyl ester and the like are thermally decomposable, and in an undecomposed state, an alkali-soluble resin. It is preferable to use a substance that substantially lowers the solubility of the toner in terms of improving the dissolution inhibition of the image area in the developer.

  Preferred examples of the onium salt used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of 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 and 4,069,056; 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 and JP-A-2-296514. Iodonium salts, J.M. 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 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. 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), a selenonium salt described in 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) in [Chemical Formula 23] [Chemical Formula 24] described in 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.

  Suitable quinonediazides include o-quinonediazide compounds. 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 sensitive material system by both the effect 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) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and 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, 49-17474, 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, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

  The amount of the onium salt and / or o-quinonediazide compound that is a degradable dissolution inhibitor is preferably 1 to 10% by mass, more preferably 1 to 5% by mass, particularly preferably the total solid content of the image recording layer. 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.

  The amount of additives other than the o-quinonediazide compound is preferably 0.1 to 5% by mass, more preferably 0.1 to 2% by mass, and particularly preferably 0.1 to 1.5% by mass. The additive and binder according to the present invention are preferably contained in the same layer.

  Further, a dissolution inhibitor having no decomposability may be used in combination, and preferred dissolution inhibitors include sulfonate esters, phosphate esters, and aromatic carboxylic acids described in detail in JP-A-10-268512. Esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as well as lactone skeletons described in detail in JP-A-11-190903, N, N- Examples thereof include an acid color-forming dye having a diarylamide skeleton and a diarylmethylimino skeleton, which also serves as a colorant, and nonionic surfactants described in detail in JP-A No. 2000-105454.

Moreover, as an additive used for the image recording layer in the present invention, cyclic acid anhydrides, phenols, and organic acids can be used in combination for the purpose of improving sensitivity. Further, a surfactant, an image colorant, and a plasticizer, which will be described later, can also be used for the positive image recording layer in the present invention.
Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, and 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, etc. Further, organic acids include Examples thereof include sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755.
The proportion of the cyclic acid anhydride, phenols, and organic acids in the image recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, and particularly preferably 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, 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 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based 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 above-mentioned 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 recording 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 image recording 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.

(Coating solvent and coating method)
The image recording layer in the present invention can be formed by dissolving each component constituting the image recording layer coating solution in a solvent and coating the solution on a suitable support. Further, depending on the purpose, a protective layer, a resin intermediate 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.
Further, the coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but in general, the coating amount after drying is preferably 0.5 to 5.0 mg / m ^2. An amount of 6 to 2.0 mg / m ² is more preferable.

  Various methods can be used as a method 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. Can be mentioned. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the photosensitive film deteriorate.

(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 the 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 at most 10% by mass. 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, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 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 planographic printing plate is easily damaged, and ink adheres to the damaged part during printing. So-called “scratch stains” easily occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. The hydrophilization treatment used in the present invention is disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are alkali metal silicate (such as aqueous sodium silicate) methods. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, it is disclosed in potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinylphosphonic acid is used.

(Undercoat layer)
The image forming material of the present invention is provided with an image recording layer as described above on a support, and an undercoat layer can be provided between the support and the image recording layer as 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 high sensitivity can be achieved. 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, which is impermeable to the alkaline developer, functions as a protective layer for the undercoat layer. Therefore, the development stability is improved and the discrimination is excellent. It is considered that an image is formed and stability over time is secured, and in the exposed portion, the components of the image recording layer whose dissolution inhibiting ability is released are quickly dissolved and dispersed in the developer, Since the undercoat layer itself that is adjacent to the support is made of an alkali-soluble polymer, it has good solubility in a developer, for example, even when a developer with reduced activity is used. 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, glycerophosphinic acid and other organic phosphinic acids, glycine and β-alanine amino acids, and triethanolamine hydrochloric acid Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of 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 ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group, and R ¹² and R ¹³ 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 ^14. , -COOR ¹⁵ , -CONHR ¹⁶ , -COR ¹⁷ or -CN, or R ¹² and R ¹³ may be bonded to form a ring, and R ^{14 to} R ¹⁷ are each independently an alkyl group or Represents an aryl group, X represents a hydrogen atom, a metal atom, or NR ¹⁸ R ¹⁹ R ²⁰ R ²¹ , and R ^{18 to} R ²¹ each independently represent a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl. Represents a group, or R ¹⁸ and R ¹⁹ may combine to form a ring, and m represents an integer of 1 to 3.

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. An acid group having an acid dissociation index (pKa) of 7 or more is preferred as the acid group, and 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 composed of Group V or Group VI atoms, more preferably an onium salt composed of nitrogen, phosphorus or sulfur atoms, and particularly preferably an onium salt composed of nitrogen atoms. 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 as 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 method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution in which the above organic compound is dissolved in the above organic solvent or a mixed solvent thereof to adsorb the above compound, then washed with water or the like and dried to provide an undercoat layer. 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 is larger than 200 mg / m ^2, it is the same.

[Application to lithographic printing plate precursor]
The image forming material of the present invention produced as described above is suitably used as a lithographic printing plate precursor and is usually subjected to image exposure and development treatment. Hereinafter, an image recording method when the image forming material of the present invention is used for a lithographic printing plate precursor will be described.

  The lithographic printing plate precursor to which the present invention is applied is image-formed 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 .

  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. A conventionally known alkaline aqueous solution can be used for the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples thereof include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. 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 above alkaline aqueous solutions, one of the developing solutions that exert the effect according to the present invention is a so-called one containing an alkali silicate as a base or containing an alkali silicate by mixing a silicon compound with a base. Another more preferable developer, which is an aqueous solution called “silicate developer” having a pH of 12 or more, does not contain an alkali silicate, and contains a non-reducing sugar (an organic compound having a buffering action) and a base. Silicate developer ".

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 1.0 to 1.5), and SiO ₂ The developer is based on gram atoms of all alkali metals present in the developer. A manner containing potassium at least 20%, aqueous solution of an alkali metal silicate is preferably used.

  Further, a so-called “non-silicate developer” which does not contain an alkali silicate and contains a non-reducing sugar and a base is more preferable for application to the development of the lithographic printing plate material of the present invention. When the development processing of the lithographic printing plate precursor is performed using this developer, the surface of the image recording layer is not deteriorated and the thickness of the recording layer can be maintained in a good state. In addition, the lithographic printing plate precursor generally has a narrow development latitude and a large change in the image line width due to the developer pH, but the non-silicate developer contains a non-reducing sugar having a buffering property that suppresses fluctuations in pH. Therefore, it is more advantageous than the case where a developing processing solution containing silicate is used. 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. Further, the effect of improving discrimination is remarkable. This is presumably because the contact (penetration) with the developer which is important in the present invention is mild, and the difference between the exposed and unexposed areas is likely to occur.

  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 in that 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, pyridine-2-aldehyde (, aldehydes such as pyridine-4-aldehyde (and the like) , Salicylic acid, 3-hydroxy-2-naphthoic acid, catechol, gallic acid, sulfosalicylic acid, 3,4-dihydroxysulfonic acid, 3,4-dihydroxybenzoic acid, hydroquinone (11.56), pyrogallol, o-, m Compounds having a phenolic hydroxyl group such as-, p-cresol, resorsonol, oximes such as acetoxime, 2-hydroxybenzaldehyde oxime, dimethylglyoxime, ethanediamide dioxime, acetophenone oxime, adenosine, inosine, guanine, cytosine, hypoxanthine , Ki Nucleic acid-related substances such as Nchin, other, diethylaminomethyl acid, benzimidazole, and the like barbituric acid is preferably exemplified.

  To the developer and replenisher, various surfactants and organic solvents are added as necessary for the purpose of promoting and suppressing developability, dispersing development residue, or improving ink affinity of the printing plate image area. it can. As the surfactant, anionic, cationic, nonionic and amphoteric surfactants are preferable. Further, the developer and replenisher may contain a reducing agent such as sodium salt and potassium salt of inorganic acids such as hydroquinone, resorcin, sulfurous acid, and bisulfite, as well as organic carboxylic acid, antifoaming agent, hard water, if necessary. Softeners and the like can be added.

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

Further, 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 PS plates 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 and replenisher 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. If necessary, the developer and replenisher may contain 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. It can also be added.
The printing plate developed using the developer and the replenisher is post-treated with water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment of the printing plate precursor according to 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 also be applied.

  In the lithographic printing plate precursor, there is an image portion unnecessary for the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, a film edge mark of the original film). In that case, 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 lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to obtain a lithographic printing plate with a higher printing durability, it is desired. The burning process is performed.
In the case of burning a lithographic printing plate, the preparation as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859 and JP-A-61-159655 is performed before burning. It is preferable to treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method in which the printing plate is immersed and applied in a vat filled with the surface-adjusting liquid, Application by an automatic 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 lithographic printing plate coated with the surface-adjusting solution 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.). The 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 lithographic printing plate can be subjected to conventional treatments such as water 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 planographic 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 1-5, Comparative Examples 1-5]
(Production of support)
An aluminum plate (material: JIS A 1050) with a thickness of 0.3 mm is etched for 10 seconds at a caustic soda concentration of 30 g / l, an aluminum ion concentration of 10 g / l, and a liquid temperature of 60 ° C., washed with running water, and washed with 10 g / l nitric acid. After neutralizing and washing with water. This was applied with an electric current of 400 C / dm ² in an aqueous solution having a hydrogen chloride concentration of 15 g / l, an aluminum ion concentration of 10 g / l and a liquid temperature of 30 ° C. using a sinusoidal alternating waveform current under the condition of applied voltage Va = 20V. Electrochemical roughening treatment was carried out in an amount and washed with water. Next, etching treatment was performed for 10 seconds at a caustic soda concentration of 30 g / l, an aluminum ion concentration of 10 g / l, and a liquid temperature of 40 ° C., and washed with running water. Next, desmut treatment was performed in a sulfuric acid aqueous solution having a sulfuric acid concentration of 15% by mass and a liquid temperature of 30 ° C., followed by washing with water. Furthermore, in a 10% by mass sulfuric acid aqueous solution at a liquid temperature of 20 ° C., an anodizing treatment was performed under a condition of a current density of 6 A / dm ² by direct current so that both anodic oxide coatings would be equivalent to 2.5 g / m ² , and washing with water. , Dried. Then, it processed for 10 second at 30 degreeC with the sodium silicate 1.0 mass% aqueous solution, and produced the support body (a) which carried out the hydrophilic process.
When the center line average roughness (Ra) of the support (a) was measured using a needle having a diameter of 2 μm, it was 0.43 μm.

(Formation of undercoat layer)
The following undercoat liquid was applied to the support (a) thus obtained, and dried at 80 ° C. for 30 seconds to provide an undercoat layer. The dry coating amount of the undercoat layer was 17 mg / m ² .
(Undercoat liquid composition)
・ The following compound 0.3g
・ Methanol 100g
・ Water 1g

(Formation of photosensitive layer)
Next, the coating liquid A having the following composition was applied to the support with the undercoat layer obtained above with a wire bar. After coating, drying was performed at 140 ° C. for 60 seconds to obtain a positive planographic printing plate precursor of Examples 1 to 4 with a total coating amount of 2.00 g / m ² .

<Coating liquid A>
・ Alkaline-soluble resin having urea bond on side chain (A) described in Table 1 Amount described in Table 1 (In the table, described as “specific polymer A”)
-(B) Alkali-soluble resin having phenolic hydroxyl group described in Table 1 Amount described in Table 1 (In the table, described as "specific polymer B")
・ (C) Cyanine dye X (the following structure) 0.05g
・ Ethyl violet 0.015g
・ Methyl ethyl ketone 20g

In addition, the detail of (B) alkali-soluble resin which has phenolic hydroxyl group of Table 1 is as follows.
(B-1): m-cresol / p-cresol (molar ratio: 60/40)
Formaldehyde novolac resin (weight average molecular weight; 4000)
(B-2): m-cresol / p-cresol (molar ratio: 40/60)
Formaldehyde novolac resin (weight average molecular weight; 10,000)

[Evaluation of planographic printing plate precursor]
Next, performance evaluation of the positive type lithographic printing plate precursors of Examples 1 to 5 and Comparative Examples 1 to 5 was performed. The evaluation test was conducted on the sample stored at 25 ° C. for 14 days after the photosensitive layer was applied.

[Evaluation of sensitivity]
The positive lithographic printing plate precursors of Examples 1 to 5 and Comparative Examples 1 to 5 were exposed by changing the beam intensity using a Trendsetter 800 manufactured by Creo, and developed by Fuji Photo Film Co., Ltd. DT-2 Development was performed using a 1: 8 dilution of water. At this time, exposure was performed while changing the exposure amount, and the minimum exposure amount at which the exposed portion was sufficiently developed under the same development conditions was defined as sensitivity. The smaller the value, the higher the sensitivity.

[Evaluation of printing durability and chemical resistance]
The obtained positive lithographic printing plate precursors of Examples 1 to 5 and Comparative Examples 1 to 5 were imaged in a test pattern with a beam intensity of 9 W and a drum rotation speed of 150 rpm with a Trend setter manufactured by Creo. It was.
Thereafter, using a PS processor 900H manufactured by Fuji Photo Film Co., Ltd., charged with an alkaline developer having the following composition, development was performed at a developing time of 20 seconds while maintaining the liquid temperature at 30 ° C. The obtained lithographic printing plate was printed with a DIC-GEOS (N) black ink manufactured by Dainippon Ink & Chemicals, Inc. using a Lithrone printing machine manufactured by Komori Corporation. The printing durability was evaluated based on the number of printed sheets at the time recognized in (1). The results are shown in Table 2 below.
Further, every time 5000 sheets were printed during printing, a process of wiping the plate surface with a cleaner (manufactured by Fuji Photo Film Co., Ltd., multi-cleaner) was added, and printing durability was evaluated in the same manner as described above. The former printing durability is called normal printing durability, and the latter printing durability is called cleaner printing durability. The results are shown in Table 2. The higher the cleaner printing durability, the better the chemical resistance.

<Alkali developer composition>
・ SiO ₂ · K ₂ O (K ₂ O / SiO ₂ = 1/1 (molar ratio)) 4.0% by mass
・ Citric acid 0.5% by mass
・ Polyethylene glycol lauryl ether (weight average molecular weight; 1,000)
0.5% by mass
・ Water 95.0 mass%

[Evaluation of development latitude]
The obtained positive type lithographic printing plate precursors of Examples 1 to 5 and Comparative Examples 1 to 5 were formed into test pattern images 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. Draw (exposure).
Next, a solution in which carbon dioxide gas was blown into the developer DT-2R manufactured by Fuji Photo Film Co., Ltd. with water dilution (1: 9) until the conductivity reached 37 mS / cm, and a finisher manufactured by Fuji Photo Film Co., Ltd. Development was carried out 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 and the liquid temperature was kept at 30 ° C., and the development time was 12 seconds.
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 lithographic printing plate precursor in which the test pattern was drawn in an image shape 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.

In the developed plates of Examples and Comparative Examples after development, the plates developed with each conductivity were checked with a magnifier of 50 times to see whether there was any stain or coloring due to poorly developed non-image area residual film. The conductivity of the developer that could be developed was determined. Next, the conductivity at which the developed film does not decrease in the unexposed area, specifically, the image density of the solid area before development is measured with a GRETAG reflection densitometer D196 (manufactured by GretagMacbeth), and 0 is determined from this image density. The electric conductivity of the developer having a solid portion having an image density of 10 or more was determined.
The development latitude was defined as the conductivity range of the developer that was able to be developed satisfactorily and the limit of conductivity at which the decrease in the developed film was maintained. The results are shown in Table 1.

(Confirmation of phase separation structure)
After immersing the fracture surfaces of the lithographic printing plate precursors of Examples 1 to 5 and Comparative Examples 1 to 5 in a water diluted (1: 8) solution of developer DT-2 manufactured by Fuji Photo Film Co., Ltd. for 10 seconds And observed with a SEM at a magnification of 30,000. The case where the sea-island structure was seen was marked with ○, and the case where the sea-island structure was not seen was marked with ×. The results are shown in Table 1.

[Solution rate ratio of alkali-soluble resin]
A sample polymer is dissolved on the surface of a PET substrate in an organic solvent suitable for the polymer, and is applied and dried. The solution concentration and the like are adjusted so that the coating amount after drying is 4 g / m ² . The polymer film coated on the PET substrate is immersed in a 3.5 wt% potassium silicate aqueous solution (SiO ₂ / K ₂ O molar ratio: 1.16) at 25 ° C. for different times and washed with water. Measure the soaking time when the film is not dissolved. The ratio of the dissolution rates of the two alkali-soluble resins is determined by the ratio of the reciprocal of this time. The results are shown in Table 1.

As described above, as shown in Table 1, the lithographic printing plate precursors of Examples 1 to 5, which are image forming materials of the present invention, have a wide development latitude and are excellent in printing durability and chemical resistance. all right.
On the other hand, of the two types of polymers, the content ratio of the specific polymer A is greater than the regulation of the present invention, or Comparative Example 1 and Comparative Example 3 not including the specific polymer B are inferior in development latitude, It can be seen that Comparative Example 2 and Comparative Example 4 that have a content ratio higher than that of the present invention or do not contain the specific polymer A are inferior in printing durability and chemical resistance.

Claims (4)

  On the support, (A) an alkali-soluble resin having a urea bond in the side chain, (B) an alkali-soluble resin having a phenolic hydroxyl group, and (C) an image recording layer containing a photothermal conversion agent, (A The weight ratio of (B) the alkali-soluble resin having a urea bond in the side chain to (B) the alkali-soluble resin having a phenolic hydroxyl group is in the range of 6: 1 to 19: 1, and in the image recording layer, An image-forming material, wherein A) an alkali-soluble resin having a urea bond in the side chain and (B) an alkali-soluble resin having a phenolic hydroxyl group form a phase separation structure.   The phase separation structure in the image recording layer is a sea-island structure in which (A) an alkali-soluble resin having a urea bond in the side chain forms a dispersion medium, and (B) an alkali-soluble resin having a phenolic hydroxyl group forms a dispersed phase. The image forming material according to claim 1.   In the image recording layer, the weight ratio of (A) the alkali-soluble resin having a urea bond in the side chain to (B) the alkali-soluble resin having a phenolic hydroxyl group is in the range of 8: 1 to 19: 1. The image forming material according to claim 1 or 2.   (A) The dissolution rate of the alkali-soluble resin having a urea bond in the side chain in the alkaline developer is at least twice the dissolution rate of the alkali-soluble resin having a phenolic hydroxyl group in the alkaline developer. The image forming material according to any one of claims 1 to 3.