JP2006091191A - Image forming material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming material which has wide development latitude, excellent plate inspection, further excellent removing ability of a non-image portion, and usefulness as a positive planographic printing original plate for an infrared laser. <P>SOLUTION: The image forming material has at least two kinds of alkali soluble resins (A), an acid coloring pigment represented by a general formula (1) (B), and an image recording layer containing an infrared ray absorber (C) on a supporting body, wherein at least a kind of the alkali soluble resin forms a dispersion phase. In the formula, rings A, B, C represent an aromatic hydrocarbon group or an aromatic heterocycle group with 1-3 nuclei, and further, at least one out of the rings B, C has at least one substituent selected from a group consisting of an amino group, an alkoxy group, an aryloxy group, an alkylthio group and an arylthio group. W<SP>1</SP>represents a carbonyl group, thiocarbonyl group, and so on, Q<SP>1</SP>represents an oxygen atom, a sulfur atom or an imino group, and R<SP>21</SP>-R<SP>24</SP>represent a hydrogen atom or a hydrocarbon group, and m and n represent 0 or 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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. Utilizing subtle changes in the intermolecular interaction of the binder in the photosensitive layer, the alkali-soluble discrimination in exposed / unexposed areas is reduced, resulting in poor development latitude (development stability depending on use conditions). There was a problem of becoming enough.

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. When a sufficient amount is added to develop the development resistance improving effect, there is a problem that the developability of the exposed area tends to be lowered.
JP 11-44956 A JP-A-11-190903

  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, the present invention provides an image forming material useful as a positive lithographic printing plate precursor for an infrared laser having a wide development latitude, excellent plate inspection, and excellent non-image area removal after exposure. The purpose is to do.

As a result of investigation, the present inventor uses an acid color-forming dye having a specific structure in the image recording layer and forms a dispersed phase with at least one alkali-soluble resin contained in the image recording layer. Thus, the inventors have found that the above object can be achieved and have completed the present invention.
That is, the image-forming material of the present invention comprises (A) at least two alkali-soluble resins, (B) an acid-coloring dye represented by the following general formula (1), and (C) an infrared absorption on a support. And an image recording layer containing an agent, wherein the image recording layer has a phase separation structure of at least two kinds of alkali-soluble resins.

In the general formula (1), ring A, ring B and ring C each independently represent an aromatic hydrocarbon group or aromatic heterocyclic group having 1 to 3 nuclei, and at least one of ring B and ring C. And at least one substituent selected from the group consisting of an amino group, an alkoxy group, an aryloxy group, an alkylthio group, and an arylthio group. Ring B and ring C may be bonded to each other via a bonding group.
W ¹ represents a carbonyl group, a thiocarbonyl group, or —C (R ²⁵ ) ═N—, wherein R ²⁵ represents a hydrogen atom or a hydrocarbon group, and Q ¹ represents an oxygen atom, a sulfur atom or an imino group. To express. R ^{21 to} R ²⁴ each independently represents a hydrogen atom or a hydrocarbon group. m and n each independently represents 0 or 1.
As such an image recording layer, it is preferable that (A) a sea-island structure in which at least one of at least two alkali-soluble resins is a dispersed phase and at least one other is a dispersion medium is formed. It is.

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 two or more kinds of alkali-soluble resins, and a phase separation structure based on the at least two kinds of alkali-soluble resins. One of the characteristics is that a sea-island structure as a phase separation structure is formed by the formation of a dispersion medium (matrix phase) due to the above, but specific acid color development in the image recording layer having such a structure When the coloring dye is added, the acid coloring dye is unevenly distributed in either the dispersed phase or the matrix phase of the phase separation structure. The phase in which the acid color-forming dye is unevenly distributed tends to deteriorate in developability due to its structure, while such a decrease in developability is not observed in the phase containing almost no acid color-forming dye. For this reason, in the unexposed area, the acid-color-forming dye has alkali resistance and excellent color developability, while in the exposed area, the acid-color-forming dye is unevenly distributed in the dispersed phase, the matrix phase is Due to the excellent alkali developer solubility of the alkali-soluble resin, the image recording layer is quickly removed together with the dispersed phase, and when the acid coloring dye is unevenly distributed in the matrix phase, the dispersed phase having excellent solubility is obtained. It is thought that alkali developability can be improved because a permeation path of an alkali developer is rapidly formed in the matrix phase and contributes to improvement of solubility. As a result, in the present invention, the image recording layer has excellent development resistance and plate inspection in the unexposed area, while a decrease in developability due to the dye is suppressed in the exposed area. It is presumed that the excellent solubility in the developing solution is manifested and thus the discrimination is increased, and the developing latitude is also 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, excellent plate inspection, and excellent removability of an exposed portion. .

The present invention will be described in detail.
The image-forming material of the present invention contains (A) at least two kinds of alkali-soluble resins, (B) an acid-coloring dye represented by the general formula (1), and (C) an infrared absorber on a support. The image recording layer is characterized in that it has a phase separation structure with at least two kinds of alkali-soluble resins, preferably a sea-island structure having a dispersed phase and a matrix phase.
Hereinafter, the components of the present invention will be described in detail. First, the acid coloring dye represented by the general formula (1), which is a characteristic component of the present invention, will be described.

[(B) Acid Coloring Dye Represented by Formula (1)]
The image recording layer in the invention needs to contain an acid color-forming dye represented by the general formula (1) (hereinafter simply referred to as an acid color-forming dye as appropriate).

In the general formula (1), ring A, ring B and ring C each independently represent an aromatic hydrocarbon group or aromatic heterocyclic group having 1 to 3 nuclei, and at least one of ring B and ring C. And at least one substituent selected from the group consisting of an amino group, an alkoxy group, an aryloxy group, an alkylthio group, and an arylthio group. Ring B and ring C may be bonded to each other via a bonding group.
W ¹ represents a carbonyl group, a thiocarbonyl group, or —C (R ²⁵ ) ═N—, wherein R ²⁵ represents a hydrogen atom or a hydrocarbon group, and Q ¹ represents an oxygen atom, a sulfur atom or an imino group. To express. R ^{21 to} R ²⁴ each independently represents a hydrogen atom or a hydrocarbon group. m and n each independently represents 0 or 1.

In the acid color-forming dye represented by the general formula (1), as a preferable compound, Q ¹ is an oxygen atom or a sulfur atom, W ¹ is a carbonyl group or a thiocarbonyl group, and ring A is benzene. Ring, piperazine ring, thiophene ring, benzothiophene ring, furan ring, benzofuran ring, indole ring, or pyridine ring, ring B and ring C are each independently a benzene ring or naphthalene ring, and m and n are R ^{21 to} R ²⁴ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an aryl group having 6 to 8 carbon atoms, and R ²⁵ is a hydrogen atom or 1 carbon atom. An alkyl group having 15 to 15 carbon atoms and an aryl group having 6 to 15 carbon atoms. Among them, Q ¹ is an oxygen atom, W ¹ is a carbonyl group, ring A is a benzene ring, and R ^{21 to} R ²⁴ are independently a hydrogen atom, a methyl group, an ethyl group, or a phenyl group. More preferred.

  Moreover, the ring A, the ring B, and the ring C may have a substituent as long as the effects of the present invention are not impaired. Examples of the substituent that can be introduced include a hydroxyl group, a halogen atom, a cyano group, a trimethylsilyloxy group, an alkyl group having 1 to 15 carbon atoms, an acyl group having 2 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, and carbon. C1-C15 alkylthio group, C1-C15 alkylsulfinyl group, C1-C15 alkylsulfonyl group, C6-C15 aryloxy group, C6-C15 arylthio group, C2-C2 ˜15 acyloxy group, C2-C15 alkoxycarbonyl group, amino group, and the like. These substituents may further have a substituent as described above. Among these substituents, a hydroxyl group, a chlorine atom, a bromine atom, a trifluoromethyl group, an alkyl group having 1 to 10 carbon atoms, a phenyl group, a tolyl group, an acyl group having 2 to 5 carbon atoms, and an alkyl group having 2 to 5 carbon atoms. An acyloxy group, a dialkylamino group having 1 to 5 carbon atoms, an alkylamino group having 1 to 5 carbon atoms, a phenylamino group, a phenylmethylamino group, an alkoxy group having 1 to 5 carbon atoms, an alkylthio group having 1 to 5 carbon atoms, Those having a phenoxy group, a phenylthio group and the like are preferable.

Ring B and ring C may be bonded to each other via a bonding group. In this case, examples of the bonding group include an oxygen atom, a sulfur atom, a methylene group, and an ethylene group. It is an oxygen atom.
When ring B and ring C are bonded, m and n are both 0, and ring B and ring C are bonded at the o-position to form a 6-membered ring.
In general formula (1), at least one of ring B and ring C has at least one substituent selected from an amino group, an alkoxy group, an aryloxy group, an alkylthio group, and an arylthio group. Is preferably present in each of ring B and ring C, and each may have two or more. Further, those having at least one amino group in each of ring B and ring C are more preferable.
In addition, the substituent selected from the amino group, alkoxy group, aryloxy group, alkylthio group, and arylthio group mentioned here further has a substituent that can be introduced into the ring A, ring B, and ring C described above. It may be.

  As the acid color-forming dye according to the present invention, a compound having two or more acid color-forming dyes represented by the general formula (1), or a plurality of dyes bonded directly or via a bonding group may be used. . As a method of binding a plurality of acid-coloring dyes, any acid-coloring dyes can be used without particular limitation as long as they are bound directly or via a bonding group.

When the compound having a plurality of acid color-forming dyes is an organic polymer, those having a weight average molecular weight (Mw) of 1,000 to 1,000,000, preferably 1,000 to 500,000, and more preferably 1,000 to 100,000 are preferred. Such an organic polymer substance having a plurality of acid-coloring dyes has a coating property on its own, and a plurality of acid-coloring dyes are localized in the molecule. Are preferably used.
Hereinafter, specific examples of the acid-coloring dyes preferably used in the present invention will be given, but the present invention is not limited thereto.

  The content of the acid coloring dye is 1 to 50% by mass, preferably 3 to 40% by mass, and more preferably 5 to 25% by mass with respect to the total solid content of the image recording layer. When the acid color-forming dye is an organic polymer (usually weight average molecular weight Mw = 1000 to 100,000), it is 1 to 95% by weight, preferably 3 to 90% by weight, based on the total solid content of the photosensitive composition. Preferably it contains in the range of 5-80 mass%.

[(A) at least two alkali-soluble resins]
The image recording layer in the invention contains at least two kinds of alkali-soluble resins, and has a phase separation structure resulting from the two kinds of alkali-soluble resins.
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, at least two alkali-soluble resins are selected so as to satisfy this condition.

  Although the preferable example of the alkali-soluble resin in this invention is described below, the alkali-soluble resin in this invention will not be specifically limited if it is resin which satisfy | fills this condition.

  Preferable alkali-soluble resins used in the present invention include phenolic resins having a structural unit represented by the following general formula (2) and a phenolic hydroxyl group.

In general formula (2), R ¹ represents a hydrogen atom or an arbitrary substituent. The arbitrary substituent referred to here may be any substituent as long as the effects of the present invention due to the structure of “—X—R ² ” described later are not impaired, and the general formula (1 And a plurality of benzene rings may be present. Specific examples include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an allyl group, and the like, but are not limited thereto. Moreover, when two or more exist, each substituent may be the same or different. Moreover, when two or more exist, each substituent may be the same or different.
X represents a divalent linking group, and preferably represents a divalent linking group having at least one partial structure selected from the group consisting of the following formulas. Here, “having at least one partial structure” means that the linking group represented by X may consist of (1) any one of the following partial structures, and (2) the following partial structures: Or a linking group obtained by linking the linking group of (1) or (2) above with another hydrocarbon group or the like. In the above (2), each of the plurality of partial structures may be the same or different, and the order of connection is also arbitrary. Moreover, the description of the following partial structure does not prescribe | regulate the connection direction of a connection group.

More preferable examples of the linking group include amide, sulfonamide, urea, urethane, thiourea, carbonyl, carboxylic acid ester (—CO—O—), sulfonyl, sulfonic acid ester (—SO ₂ —O—) and the like. Although the structure shown below is mentioned specifically, this invention is not limited to these. Moreover, the description of the following partial structure does not prescribe | regulate the connection direction of a connection group.

R ² is a monovalent substituent which has two or more hydrogen bonds capable of forming a hydrogen bond, and has two or more hydrogen bonds that are thermally reversible, that is, thermally releasable. Represents.
Here, the lone pair binding site refers to a site capable of forming a hydrogen bond with a hydrogen atom capable of hydrogen bonding, which will be described later, specifically, = O, = N-, = S, = P-, Among them, from the viewpoint of forming a stronger hydrogen bond with a hydrogen atom, ═O and ═N— are preferable.

  The hydrogen atom capable of hydrogen bonding refers to an active hydrogen atom capable of hydrogen bonding with the above-mentioned lone pair binding site, specifically, a hydrogen atom, oxygen atom covalently bonded to a nitrogen atom, and Examples include a hydrogen atom that is covalently bonded, a hydrogen atom that is covalently bonded to a sulfur atom, a hydrogen atom that is covalently bonded to a phosphorus atom, and the like. From the viewpoint of formation, a hydrogen atom covalently bonded to a nitrogen atom and a hydrogen atom covalently bonded to an oxygen atom are preferable. .

Specific examples of the structure of R ² include structures shown in the following general formulas (R-1) to (R-7). Here, R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or a hydrocarbon group, and Y represents a hydrocarbon linking group.

  The phenolic resin having the structural unit represented by the general formula (2) and the phenolic hydroxyl group may be one having a phenolic hydroxyl group in the molecule together with the structural unit represented by the general formula (2). Any of them can be used. Especially, what introduce | transduced the structural unit represented by the said General formula (2) to a novolak resin, a resole resin, polyhydroxystyrene resin, etc. is preferable.

  Moreover, as the phenolic resin having the structural unit represented by the general formula (2) and the phenolic hydroxyl group, the phenolic hydroxyl group present in the molecule is represented by the following general formula (3). An embodiment introduced into the molecule as such a structural unit is preferable, and in particular, from the structural unit represented by the general formula (2) and the structural unit represented by the following general formula (3) as follows: Most preferably, the resin is constituted.

R < ³ > in General formula (3) represents a hydrogen atom or arbitrary substituents each independently. Here, arbitrary substituents are synonymous with R < ¹ > in the said General formula (2), Moreover, two or more with respect to one benzene ring in General formula (3) may exist. When present, each substituent may be the same or different.

  As the copolymerization ratio of the structural unit represented by the general formula (2) (structural unit (1)) and the structural unit represented by the general formula (3) (structural unit (2)), chemical resistance From the viewpoint of sensitivity, the structural unit (1): structural unit (2) is preferably in the range of 1:99 to 95: 5, and more preferably in the range of 2:98 to 90:10. Most preferably, it is in the range of 3:97 to 80:20. The modified phenolic resin may have a copolymer component other than the structural unit (1) and the structural unit (2).

  Specific examples of the alkali-soluble resin comprising the structural unit represented by the general formula (2) and the structural unit represented by the general formula (3) (Exemplary compounds (A-1) to (A-5)) However, the present invention is not limited to these.

  Moreover, as another example of preferable alkali-soluble resin in this invention, the polymer which has a structural unit represented by following General formula (4) is mentioned.

In the general formula (4), X represents a divalent linking group, and R ¹ represents an alkyl group or an aryl group. x represents 0 or 1;
X preferably represents an alkylene group, a linking group represented by the following general formula (4-2), or a linking group represented by the general formula (4-3).

In the general formula (4-2) or the general formula (4-3), x independently represents 0 or 1. R ³ and R ⁴ in the general formula (4-3) each independently represent a hydrogen atom or an alkyl group.

When X represents an alkylene group, an alkylene group having 1 to 10 carbon atoms is preferred, further preferably 1 to 6 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and most preferably —CHR. ² —CH ₂ — (wherein R ² — represents a hydrogen atom or a substituent similar to those listed below as substituents that can be introduced into the alkylene group).
The alkylene group may have a substituent, but two or more substituents of the alkylene group are not linked to each other to form a ring structure, and the alkylene group has an aliphatic group in the structure. No cyclic hydrocarbon structure. Examples of the substituent that can be introduced into the alkylene group include a halogen atom, a hydroxy group, an alkyl group, an alkoxy group, and a phenyl group, and these substituents may further have the same substituent.

R ¹ represents an alkyl group or an aryl group.
When R ¹ represents an alkyl group, the alkyl group may be any of a linear structure, a branched chain, and a ring structure. More specifically, when R ¹ represents an alkyl group, the alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 16 carbon atoms, and most preferably an alkyl group having 1 to 12 carbon atoms. It is.

The alkyl group and aryl group may each have a substituent, and when these have a ring structure, they may have a heterocyclic structure having a hetero atom, preferably an alicyclic structure. Or what has an aromatic ring structure is mentioned.
As what has the said alicyclic structure, Preferably, what is selected from the cycloalkyl group, the cycloalkenyl group, or the cycloalkynyl group is mentioned. As a preferred alicyclic group, the number of atoms constituting the ring is preferably 5 or 6, and particularly preferably a 6-membered ring. Specifically, it can be selected from a cycloalkyl group and a cycloalkenyl group, preferably a cycloalkyl group, and preferably cyclopentyl and cyclohexyl. Of these, cyclohexyl is particularly preferred.
When R ¹ represents an aryl group, preferred is a phenyl group.

When R ¹ has a substituent, examples of the substituent that can be introduced include a hydroxy group, an alkoxy group that may further have a substituent, a hydroxyalkyloxy group, and a —SO ₂ NR ⁴ R ⁵ group (here, R ⁴ and R ⁵ each independently represents a hydrogen atom or an alkyl group, preferably a hydrogen atom).
Moreover, when introducing the substituent for adding another function to the polymer which has a structural unit represented by the said General formula (4), it can introduce | transduce into the substituent part of this R < ¹ >. Examples of such a functional group include a functional group containing a radiation-sensitive atom or group, a functional group that increases the thermal sensitivity of a polymer compound, a dye-containing group, a group containing an ethylenically unsaturated double bond such as an acrylate, and a support. And groups that improve the adhesion of the polymer compound to the substrate.

In general, preferred substituents introduced into R ¹ are, as described above, a hydroxy group, an optionally substituted alkoxy group, an optionally substituted hydroxyalkyl group, and It is a —SO ₂ NR ⁶ R ⁷ group, and particularly preferred substituents are a hydroxy group and a —SO ₂ NR ⁶ R ⁷ group. Here, R ⁶ R ⁷ each independently represents a hydrogen atom or an alkyl group.
When R ¹ represents a phenyl group, the introduced substituent is preferably substituted at the 4-position.
R ¹ may have one or more optional substituents as described above, but is preferably unsubstituted or has one introduced substituent.

The polymer according to the present invention having the structural unit represented by the general formula (4) may be composed only of the structural unit, but is preferably a copolymer having a plurality of structural units. The plurality of structural units may be structural units different from each other represented by the general formula (4), or may be a combination of the structural unit represented by the general formula (4) and another structural unit.
Other structural units that can be used in combination include (meth) acrylic acid, but in all polymers. The structural unit represented by the general formula (4) is preferably 5% by mass or more, and more preferably 10% by mass or more.

  Specific examples of the polymer having the structural unit represented by the general formula (4) (specific polymer 1 to specific polymer 16) are shown below, but the present invention is not limited thereto.

  The weight average molecular weight of the polymer having the structural unit represented by the general formula (4) used here is preferably 1,000 or more and less than 500,000, and the molecular weight is preferably 2,000 or more, more preferably 10 1,000 or more, particularly preferably 100,000 or more. The molecular weight is preferably less than 400,000, more preferably less than 300,000, and more preferably less than 200,000. The molecular weight of the polymer according to the present invention can be arbitrarily selected depending on the purpose in the above range. For example, a polymer having a molecular weight in the range of 1,000 to 2,500 is also in the range of 100,000 to 500,000. Molecular weight polymers can also be suitably used.

  Such a polymer can be obtained, for example, by the method described in JP-T-2002-517786, and the polymers described herein and modified products thereof can also be suitably used in the photosensitive layer according to the present invention.

  In addition, as the alkali-soluble resin in the present invention, a phenolic resin that does not include the structural unit represented by the general formula (2) or the general formula (4) can also be suitably used. Preferred examples of such phenolic resins 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- are particularly preferable. Cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, o-, m- / p-mixed, m- / o-mixed and o- / p-mixed Good) 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, Shirenoru / novolak / phenol mixed resin, and the like. 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. .

  In addition to the phenolic resin described above, the alkali-soluble resin in the present invention is also suitable for resins having the acidic groups listed in the following (1) to (6) in the main chain and / or side chain of the polymer. Can be used.

(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )
In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrogen atom or a hydrocarbon group which may have a substituent. .

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

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

As alkali-soluble resin which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.
(1) Examples of the compound having a phenol group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.

  (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 a C 1-12 alkylene group, cycloalkylene group, arylene group, or aralkylene group that may have a substituent. . 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 represent a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a single bond or a substituent. Y ^1, Y ² represents a single bond or CO independently.

  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 (1) 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 copolymer preferably contains 10 mol% or more of a compound having an acidic group selected from (1) to (6) to be copolymerized, and is contained in an amount of 20 mol% or more. Those are more preferred. If it is less than 10 mol%, the development latitude tends to be insufficiently improved.

  Examples of the monomer component to be copolymerized with the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group include the monomers listed in (m1) to (m12) below. 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 the image recording layer, it is necessary to contain a resin capable of forming at least two kinds of phase separation structures. The total addition amount of these alkali-soluble resins is 30 to 99 mass in the total solid content of the image recording layer. %, Preferably 40 to 95% by mass, particularly preferably 50 to 90% by mass. 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) infrared absorber” described later decreases. Sensitivity decreases, which is not preferable.

-Phase composition-
As described above, the image recording layer in the present invention has a configuration in which at least one of a plurality of types of alkali-soluble resins forms a dispersed phase, that is, a resin having a high alkali solubility (sea portion) and an alkali dissolution. It is characterized by forming a so-called phase separation structure in which a low-resin resin (island portion) forms a sea-island structure. The details of such a phase separation structure are, for example, as described in JP-A-11-44956.
The phase separation structure (sea-island structure) can be formed by selecting at least two types of resins that are compatible with each other and do not form a homogeneous phase from the above-mentioned alkali-soluble resins and using them in combination. In the present invention, a preferable blend ratio of the alkali-soluble resin constituting the dispersed phase and the alkali-soluble resin constituting the dispersion medium is 1:99 to 99: 1 from the viewpoint of sea-island structure formability, and a more preferable blend ratio. Is 5: 95-95: 5.
The above-mentioned (B) acid color-forming dye is contained unevenly in one of the two alkali-soluble resins when forming the image recording layer, and is contained in a large amount in either the dispersed phase or the matrix phase of the phase separation structure. Will be. For example, in the case of a combination of an acrylic polymer and a novolac resin, there is a strong tendency to be unevenly distributed in the novolac resin phase.

[(C) Infrared absorber]
The infrared absorber in the present invention refers to a substance having a light absorption region in the infrared region of 700 nm or more, preferably 750 to 1200 nm, and exhibiting light / heat conversion ability by light in the wavelength region of this range. Specifically, various dyes or pigments that absorb light in the wavelength range and 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. Further, 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 dye represented by the following general formula (a) is 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 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 or 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, a hexagonal salt, in view of the storage stability of the recording layer coating solution. Fluorophosphate ions and aryl sulfonate ions.

  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), L represents a methine chain having 7 conjugated carbon atoms, and 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, 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 pigments or dyes are 0.01 to 50% by mass, preferably 0. 0% by mass, based on the total solid content of the photosensitive composition, from the viewpoint of balance between sensitivity and uniformity and durability of the image recording layer. 1 to 10% by mass, particularly preferably 0.5 to 10% by mass in the case of a dye, and particularly preferably 0.1 to 10% by mass in the case of a pigment.

[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, 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 recording layer. Is in the range of 1-2% by weight. 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 recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably 0.1 to 0.1% by mass. 10% by 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 dirt” is likely to 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 U.S. Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinyl phosphonic 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 recording layer functions as a heat insulating layer, and the heat generated by the infrared laser exposure does not diffuse to the support and can be used efficiently. Therefore, there is an advantage that high sensitivity can be achieved. In addition, since the 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, the sensitivity to the infrared laser is maintained well.
In the unexposed area, the recording layer itself that is impermeable to the alkaline developer functions as a protective layer for the undercoat layer, so that the development stability is good and the image is excellent in discrimination. In the exposed area, the components of the recording layer whose dissolution inhibiting ability has been released are quickly dissolved and dispersed in the developer. Since the undercoat layer itself, which 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 rapidly without the formation of a film and the like and contributes to the 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 naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphonic acid, alkylphosphoric acid and glycerophosphoric acid 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 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, and then washed and dried with water or the like 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 a basic substance such as ammonia, triethylamine or potassium hydroxide, or an acidic substance such as hydrochloric acid or 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, trisodium 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. In addition, 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 this developer is used to develop the lithographic printing plate precursor, the surface of the 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. 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 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. A method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber as described in JP-A-59-174842 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, before burning, an adjustment as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. 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 the surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The planographic 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 The heating temperature and time in this case are preferably in the range of 180 to 300 ° C. and 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 to 4]
(Production of support)
The support body was produced by processing through the process shown below using a JIS-A-1050 aluminum plate with a thickness of 0.3 mm.

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

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

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

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

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

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

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

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

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

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

<Support A>
The steps (a) to (j) were sequentially performed, and the support A was produced so that the etching amount in the step (e) was 3.4 g / m ² .
<Support B>
A support B was prepared by sequentially performing the steps except that the steps (g), (h), and (i) were omitted.

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

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

<Support E>
An aluminum plate having a thickness of 0.24 mm was degreased with an aqueous solution of sodium hydroxide, and this was electropolished in a 20% hydrochloric acid bath to obtain a grained plate having a center line average roughness (Ra) of 0.5 μm. . Then, this grained plate was anodized in a 20% sulfuric acid bath at a current density of 2 A / dm ² to form an oxide film of 2.7 g / m ² , washed with water and dried to provide an aluminum support. Body E was obtained.

[Undercoating]
On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds. The coating amount after drying was 15 mg / m ² .
(Undercoat liquid)
-0.3 g of the following polymer compound (I or II)
・ 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>
-(A) alkali-soluble resin described in Table 1 0.80 g
-(A) phenol / m-cresol / 1,5-xylenol (molar ratio: 50/30/20, weight average molecular weight: 5,000) 0.20 g
-(B) Acid coloring pigment described in Table 1 0.15 g
-(C) Cyanine dye X (the following structure) 0.017 g
・ Ethyl violet 0.015g
・ Methyl ethyl ketone 20g

[Comparative Example 1]
A lithographic printing plate precursor of Comparative Example 1 was obtained in the same manner as in Example 1, except that (B) the acid color-forming dye was not used in coating solution A. Similarly, the second alkali-soluble resin (a-2) described in Table 1 was not added to the coating liquid A in Example 1, and (a-1) phenol / m-cresol / 1,5-xylenol (mol) The lithographic printing plate precursor of Comparative Example 2 was prepared in the same manner except that only 1.00 g of (50: 30/20, weight average molecular weight: 5,000) was added, and (B) no acid color-forming dye was used. Obtained. A lithographic printing plate precursor of Comparative Example 3 was obtained in the same manner except that the coating solution A used in Comparative Example 2 was further added with the (B) acid color-forming dye described in Table 1.

Example 5
The coating liquid B having the following composition was applied to a support with an undercoat layer obtained in the same manner as in Example 1 with a wire bar. After coating, drying at 140 ° C. for 60 seconds was performed to obtain a positive planographic printing plate precursor of Example 5 with a total coating amount of 1.80 g / m ² .
<Coating liquid B>
(A) m-cresol / p-cresol (molar ratio: 60/40, weight average molecular weight: 5,000) 0.20 g
(A) N- (p-phenylsulfonamide) obtained in Synthesis Example 1 below
-Substituted (methyl vinyl ether / maleimide) copolymer 0.80 g
-(B) Acid coloring pigment described in Table 1 0.12 g
・ 0.003 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.03g
・ (C) Cyanine dye X (the above structure) 0.017 g
・ Victoria Pure Blue (Dye with BOH counter anion as 1-naphthalenesulfonic acid anion) 0.015g
・ Γ-Butyllactone 10g
・ Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

(Synthesis Example 1)
[Synthesis of N- (p-phenylsulfonamido) -substituted (methyl vinyl ether / maleimide) copolymer]
A 20% by weight solution (156 g) of Gantrez AN119 (trade name, molecular weight: 190,000 linear methyl vinyl ether / maleic anhydride copolymer, manufactured by ISP, USA) using anhydrous n-methylpyrrolidone (NMP) was placed in a beaker. , Dissolved in anhydrous NMP (300 g). After dissolution, p-aminobenzenesulfonamide (hereinafter appropriately referred to as sulfanilamide) (34,46 g) was added and dissolved while stirring. Thereafter, dimethylaminopyridine (0.2 g) was added to the solution, and after stirring for 45 minutes at room temperature, it was heated at 90-95 ° C. for 1 hour by being immersed in a hot water bath. The mixture was cooled and left overnight.

  Put 2 liters of distilled water containing 10 ml of concentrated hydrochloric acid into a 3 liter beaker and stir well. The reaction mixture obtained above was poured very slowly into a beaker in a narrow stream while continuing to stir. As a result, an N- (p-phenylsulfonamide) -substituted (methyl vinyl ether / maleimide) copolymer having the following structure was obtained. Formed and precipitated as a tan-pink suspension. The mixture was stirred for 2 hours and then allowed to settle. The precipitate was filtered and resuspended in 2 liters of water for 2 hours, then filtered and dried in a fan oven overnight to give dark brown granules (48.4 g: 78.0% yield). )

[Evaluation of planographic printing plate precursor]
Next, performance evaluation of the positive planographic printing plate precursors of Examples 1 to 5 and Comparative Examples 1 to 3 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 3 were exposed by changing the beam intensity with 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.

(Density evaluation of image area and non-image area)
Standard exposure and development (Creet Trendsetter 800, beam intensity 10.0 W, drum rotation speed 250 rpm, exposure using Fuji Photo Film Co., Ltd. developer DT-2 with water dilution (1: 8)) The image density of the subsequent image part (solid part) and non-image part was measured with a GRETAG reflection densitometer D196 (manufactured by GretagMacbeth). The greater the density difference between the image area / non-image area, the better the plate inspection. The results are shown in Table 1.

(Evaluation of development latitude)
The positive lithographic printing plate precursors of Examples 1 to 5 and Comparative Examples 1 to 3 thus obtained were drawn in a test pattern image on a Trend setter 800 manufactured by Creo under the conditions of a beam intensity of 10.0 W and a drum rotation speed of 250 rpm. (Exposure) was performed.
Next, a solution in which carbon dioxide gas was blown into the developer DT-2R manufactured by Fuji Photo Film Co., Ltd. in water (1: 9) until the electrical conductivity reached 37 mS / cm, and a finisher manufactured by Fuji Photo Film Co., Ltd. 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 3 in a water dilution (1: 8) solution of developer DT-2 manufactured by Fuji Photo Film Co., Ltd. for 10 seconds, magnification Observed with 30,000 times SEM. 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.

Details of the “alkali-soluble resin” and “acid-coloring dye” described in Table 1 are shown below.
(A-1): Phenol / m-cresol / 1,5-xylenol (molar ratio: 50/30/20, weight average molecular weight: 5,000)
(A-2): Resin (A-1) (the following structural formula, weight average molecular weight: 4,000)
(A-3): Resin (A-2) (the following structural formula, weight average molecular weight: 5,000)
(A-4): Resin (A-3) (the following structural formula, weight average molecular weight: 3,000)
(A-5): Resin (A-4) (the following structural formula, weight average molecular weight: 4,000)
(A-6): m-cresol / p-cresol (molar ratio: 60/40, weight average molecular weight: 5,000)
(A-7): N- (p-phenylsulfonamide) -substituted (methyl vinyl ether / maleimide) copolymer

As described above, as shown in Table 1, it was found that 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 excellent chemical resistance.
On the other hand, the lithographic printing plate precursor of Comparative Example 1, which uses two types of alkali-soluble resins and has a phase separation structure, but does not have an acid color-forming dye, is inferior in development latitude and sensitivity compared to the examples. I understood it. Comparative Examples 2 and 3 which do not form a phase separation structure with two kinds of alkali-soluble resins are significantly inferior in both sensitivity and development latitude. In contrast to Comparative Examples 2 and 3, even if an acid coloring dye is contained, the plate inspection is performed. It can be seen that there is no improvement other than sex, and that the sensitivity is lowered.

Claims (2)

On the support, it has an image recording layer containing (A) at least two alkali-soluble resins, (B) an acid coloring dye represented by the following general formula (1), and (C) an infrared absorber. An image forming material having a phase separation structure of at least two kinds of alkali-soluble resins in the image recording layer.

In the general formula (1), ring A, ring B and ring C each independently represent an aromatic hydrocarbon group or aromatic heterocyclic group having 1 to 3 nuclei, and at least one of ring B and ring C. And at least one substituent selected from the group consisting of an amino group, an alkoxy group, an aryloxy group, an alkylthio group, and an arylthio group. Ring B and ring C may be bonded to each other via a bonding group.
W ¹ represents a carbonyl group, a thiocarbonyl group, or —C (R ²⁵ ) ═N—, wherein R ²⁵ represents a hydrogen atom or a hydrocarbon group, and Q ¹ represents an oxygen atom, a sulfur atom or an imino group. To express. R ^{21 to} R ²⁴ each independently represents a hydrogen atom or a hydrocarbon group. m and n each independently represents 0 or 1.   The phase separation structure in the image recording layer is (A) a sea-island structure in which at least one alkali-soluble resin forms a dispersed phase and at least one other forms a dispersion medium among at least two alkali-soluble resins. The image forming material according to claim 1.