JP5068681B2 - Planographic printing plate precursor - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor, and more particularly to a so-called direct lithographic printing plate precursor capable of direct plate making by scanning infrared laser light based on a digital signal from a computer or the like.

  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. The 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 image recording layer. Because of the subtle changes in the intermolecular interaction of the binder in the photosensitive layer, the alkali-soluble discrimination in exposed / unexposed areas is reduced, and the development latitude (development stability depending on usage conditions) is reduced. There was a problem of becoming insufficient.

  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, such an image forming material in which the image recording layer has a phase separation structure has insufficient film strength of the image recording layer itself.

  In addition, a technique for adding a crosslinkable compound to a positive photosensitive composition has been proposed for the purpose of improving the contrast between an exposed area and an unexposed area (see, for example, Patent Document 2). Although such a photosensitive composition can provide a high printing durability by performing a burning treatment after exposure and development, it still has insufficient developability in the exposed area, and development stability due to fluctuations in use conditions. A technique for further improving the property (development latitude) has been desired.

As a technique applicable to the positive type lithographic printing plate precursor, for the purpose of improving the image forming property and the like, an image forming element having a multilayer structure, which contains a lower layer containing a polymer that can be removed by an alkali developer, and an epoxy An ink-receptive upper layer containing a polymer binder with pendant groups has been proposed (see, for example, Patent Document 3). However, the positive lithographic printing plate precursor to which this technology is applied has a problem that the sensitivity and the development latitude are insufficient.
JP 11-44956 A JP 11-202481 A US Pat. No. 7,160,653B1

  The present invention has been made to overcome the drawbacks of the prior art, and it is an object of the present invention to achieve the following objects. That is, an object of the present invention is to provide a positive planographic printing plate precursor having high sensitivity and a wide development latitude.

Means for solving the above-mentioned problems are as follows.
That is, the lithographic printing plate precursor according to the invention comprises a positive image recording layer containing a water-insoluble and alkali-soluble resin and an infrared absorber on a support, and a polymer represented by the general formula (I) described later. It has the overcoat layer containing these in this order, It is characterized by the above-mentioned.

  The positive image recording layer in the present invention preferably contains at least two water-insoluble and alkali-soluble resins, and has a phase separation structure of the at least two water-insoluble and alkali-soluble resins. Such a positive image recording layer has a sea-island structure in which at least one of at least two water-insoluble and alkali-soluble resins forms a dispersed phase and at least one other forms a dispersion medium. Is a preferred embodiment. By having the overcoat layer and the sea-island structure positive recording layer in the present invention, the positive lithographic printing plate precursor of the present invention is highly sensitive and has an excellent effect of having a wide development latitude. Can be demonstrated.

  According to the present invention, it is possible to provide a positive lithographic printing plate precursor having high sensitivity and a wide development latitude.

The present invention will be described in detail.
The lithographic printing plate precursor according to the invention contains, on a support, a positive-type image recording layer containing a water-insoluble and alkali-soluble resin and an infrared absorber, and a polymer represented by the following general formula (I) It has the overcoat layer which carries out in this order.
Hereinafter, the components of the present invention will be described in detail.

(Overcoat layer)
The overcoat layer in the present invention is a layer containing a polymer represented by the following general formula (I) .

The overcoat layer is a layer located farthest from the support among the layers existing on the support. In the present invention, a positive image recording layer exists between the overcoat layer and the support. Although an intermediate layer may further exist between the overcoat layer and the positive image recording layer, an embodiment in which the overcoat layer and the positive image recording layer are adjacent to each other is more preferable.
The overcoat layer preferably does not substantially contain a compound having infrared absorbing ability. Moreover, it is preferable that an overcoat layer does not contain the compound which acts as a hardening | curing agent of an epoxy group.

<Polymer represented by formula (I) >
The polymer represented by the general formula (I) (hereinafter referred to as “specific polymer” as appropriate) will be described.

Specific polymer chromatography is represented by below-described formula (I), having an epoxy group and ethylene glycol group in the side chain include acrylic resins.

  The epoxy equivalent in the specific polymer is preferably from 150 to 1500, and more preferably from 250 to 1200, from the viewpoints of sensitivity stability and production suitability. Here, “epoxy equivalent” means a value obtained by dividing the mass (g) of a polymer by the equivalent (number of moles) of an epoxy group in the polymer.

  As an aspect of introducing an epoxy group into a specific polymer, for example, a1) an aspect using a monomer having an epoxy group as a monomer for synthesizing a specific polymer, a2) a reactive compound having an epoxy group at the time of synthesizing the specific polymer A3) An embodiment in which an epoxy group is introduced by a known method after the synthesis of a specific polymer.

  Examples of the mode of introduction of the ethylene glycol group into the specific polymer include a mode in which a monomer having an ethylene glycol group is used as a monomer for synthesizing the specific polymer.

  The specific polymer is preferably an acrylic resin derived from a monomer having an ethylenically unsaturated bond. The acrylic resin is preferably synthesized using at least one monomer each having an epoxy group and an ethylenically unsaturated bond and at least one monomer having an ethylene glycol group and an ethylenically unsaturated bond.

Specific polymer chromatography is a polymer represented by the following general formula (I).

  In general formula (I), R ¹ Represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. R ² Represents a substituted or unsubstituted aliphatic group having an epoxy group. L ¹ Represents a single bond or a divalent linking group. R ³ Represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms. R ⁴ Represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. L ² Represents a divalent linking group. l represents 5-90 mass%. m represents 3-80 mass%. n represents an integer of 1 to 20.

In general formula (I), examples of the alkyl group represented by R ¹ include a methyl group, an ethyl group, a chloromethyl group, an isopropyl group, and a benzyl group .
R ¹ is preferably a hydrogen atom or a substituted or unsubstituted methyl group, more preferably a hydrogen atom or an unsubstituted methyl group .

In the formula (I), as the aliphatic group represented by R ^2, for example, substituted or unsubstituted glycidyl groups, such as 3,4-epoxycyclohexylmethyl group.
R ² is preferably a glycidyl group or a 3,4-epoxycyclohexylmethyl group.

In the general formula (I), the divalent linking group represented by L ¹ is a substituted or unsubstituted alkylene group, arylene group, cycloalkylene group, or aromatic or non-aromatic divalent heterocyclic group. These groups are connected to each other or bonded to carbon atoms constituting the polymer main chain through a carbonyl group, an oxo group, a sulfo group, or an amide group.

  As the substituted or unsubstituted alkylene group, an alkylene group having 1 to 6 carbon atoms is preferable. Specifically, a methylene group, a 1,2-ethylene group, a 1,1-ethylene group, an n-propylene group, an iso- A propylene group, t-butylene group, n-butylene group, n-hexylene group, etc. are mentioned.

  The substituted or unsubstituted arylene group is preferably an arylene group having an aromatic ring having 6 to 10 carbon atoms, and specifically includes a 1,4-phenylene group, a naphthylene group, and 2-methyl-1,4-phenylene. Group, 4-chloro-1,3-phenylene group, and the like.

  As the substituted or unsubstituted cycloalkylene group, a cycloalkylene group having a ring structure having 5 to 7 carbon atoms is preferable, and specific examples include a cyclopentylene group and a 1,4-cyclohexylene group. .

  The substituted or unsubstituted aromatic or non-aromatic divalent heterocyclic group includes 5 to 10 carbon atoms and one or more hetero atoms (nitrogen atom, oxygen atom, or sulfur atom) in the ring structure. And a divalent heterocyclic group including a pyridene group, a pyrazylene group, a pyrimidylene group, a thiazolylene group, and the like.

The divalent linking group represented by L ¹ may be a combination of two or more selected from the above-described alkylene groups, arylene groups, cycloalkylene groups, and heterocyclic groups.

L ¹ is more preferably a carboxylic acid ester group. Examples of the carboxylic acid ester group include —C (O) O-alkylene group, —C (O) O-alkylene-phenylene group, and —C (O) O-phenylene group. Carbon number is 1-4. X is particularly preferably a —C (O) O-alkylene group having a C 1-2 alkylene group.

  Examples of the monomer having an epoxy group and an ethylenically unsaturated bond that can be used for the synthesis of the specific polymer include glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl methacrylate, and 3,4-epoxycyclohexyl acrylate. These monomers may be used alone or in combination.

  In general formula (I), l represents 5-90 mass%, 7-75 mass% is preferable and 10-60 mass% is more preferable.

R ³ in the general formula (I) is preferably a hydrogen atom or a methyl group.
R ⁴ in the general formula (I) is preferably a hydrogen atom or a methyl group, more preferably a methyl group.
In the general formula (I), the divalent linking group represented by L ² is one selected from —C (O) O—, an alkylene group, an arylene group, a cycloalkylene group, and a heterocyclic group, or It may be a combination of two or more, and is more preferably a carboxylic acid ester group. Examples of the carboxylic acid ester group include —C (O) O—, —C (O) O-alkylene group, —C (O) O-alkylene-phenylene group, and —C (O) O-phenylene group. Here, the alkylene group preferably has 1 to 4 carbon atoms, and is —C (O) O— or —C (O) O-alkylene group having an alkylene group having 1 to 2 carbon atoms. It is particularly preferred.
N in the general formula (I) represents an integer of 1 to 20, more preferably 1 to 10, and still more preferably 2 to 8.

  In general formula (I), m represents 3-80 mass%, 7-60 mass% is preferable and 10-40 mass% is more preferable.

  In addition, the ratio of l and m in the general formula (I) is preferably 95: 5 to 5:95, more preferably 90:10 to 10:90, and still more preferably 85:15 to 20:80.

The polymer represented by the general formula (I) may have a repeating unit other than the above-described repeating unit having an epoxy group and the repeating unit having an ethylene glycol group.
Examples of monomers that can form other repeating units that can be introduced into the general formula (I) include (meth) acrylates, (meth) acrylamides, vinyl ethers, vinyl esters, vinyl ketones, olefins, Saturated imides (for example, maleimide), N-vinylpyrrolidones, N-vinylcarbazoles, vinylpyridines, (meth) acrylonitriles, and styrenes are included, but are not limited thereto. Among these monomers, (meth) acrylates, (meth) acrylamides, and styrenes are preferable, and styrenes are particularly preferable.

  Other repeating units that can be introduced into the general formula (I) may be formed using two or more monomers. Examples of such monomer combinations include a combination of a styrene monomer and methacrylamide, acrylonitrile, maleimide, or N-vinylpyrrolidone.

  As a content rate of the other repeating unit which can be introduce | transduced in general formula (I), 0-75 mass% is preferable, 5-60 mass% is more preferable, 15-55 mass% is still more preferable.

  One preferred embodiment of the specific polymer is a repeating unit derived from one or more monomers selected from glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl methacrylate, and 3,4-epoxycyclohexyl acrylate. A repeating unit derived from one or more monomers selected from monomers having an ethylene glycol group (for example, monomer A and monomer B in the examples described later), and one or more styrenes And a repeating unit derived from a monomer.

  The weight average molecular weight (Mw) of the specific polymer is preferably in the range of 5,000 to 200,000.

  Specific examples of the specific polymer include, but are not limited to, the polymers B-1 to B-4 described in Examples described later and the following polymers. In addition, all of the polymers listed below have a weight average molecular weight (Mw) in the range of 5,000 to 200,000.

  The specific polymer can be synthesized by appropriately selecting a conventionally known condensation polymerization method or addition polymerization method according to the mode of the polymer. The raw material and the reaction conditions can also be set as appropriate according to the polymer mode. A typical synthesis example will be described later.

  As for content of the specific polymer in an overcoat layer, 20-99.9 mass% is preferable in the dry mass of the whole overcoat layer, 45-95 mass% is more preferable, 65-90 mass% is still more preferable.

<Other ingredients>
The overcoat layer may contain one or more polymers other than the monomer or the specific polymer. Such monomers or polymers include benzoquinone diazide and / or naphtho, such as the phenolic resins described in US Pat. Nos. 5,705,308 and 5,705,322. Examples include compounds containing quinonediazide. Examples of such a compound include pyrogallol acetone resin (manufactured by PCAS Co., Ltd.) marketed under the trade name: P-3000. Other examples include compounds containing diazide described in US Pat. Nos. 6,294,311 and 5,143,186.

The overcoat layer may contain a colorant, if desired.
Examples of the colorant include triallylmethane dyes described in US Pat. No. 6,294,311. Specific examples include ethyl violet, crystal violet, malachite green, brilliant green, and Victoria blue. B, Victoria Blue R, Victoria Pure Blue RO and the like. These compounds can act as image colorants for distinguishing non-image areas from image areas after development.

  When the overcoat layer contains a colorant, the content is not limited, but is preferably 0.1 to 30% by mass, and preferably 0.2 to 5% by mass in the dry mass of the overcoat layer. It is more preferable.

  If desired, the overcoat layer may be an image colorant, a printout agent, a coating surfactant, a dispersion aid, a wetting agent, a bactericide, a viscosity modifier, a drying agent, an antifoaming agent, an antiseptic, an antioxidant, Etc. may be contained. The use of a coating surfactant is particularly preferred.

  A suitable composition of the overcoat layer is, for example, 99% by mass of one or more specific polymers, 0.3% by mass of a colorant, 0.7% by mass of a surfactant for coating, In the total dry mass of

  The overcoat layer can be formed by applying and drying an overcoat layer coating solution prepared by dissolving the constituent components of the overcoat layer containing at least the specific polymer in a solvent on the positive image recording layer. As the coating solvent, the solvents listed in the description of the positive image recording layer described later can be appropriately selected and used.

  Various methods can be used as a method for applying the overcoat 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.

The coating amount of the overcoat layer (solid content), the coating amount after ^drying, the range of 0.05g / ^{m 2} ~1.0g / m 2 are ^preferred, 0.1g / m 2 ^~0.5g / m more preferably ^{2 ranges,} the range of 0.15g / ^{m 2} ~0.3g / m 2 is more preferable.

(Positive image recording layer)
The lithographic printing plate precursor according to the invention contains a water-insoluble and alkali-soluble resin and an infrared absorber.

<Water-insoluble and alkali-soluble resin>
The positive type image recording layer contains an insoluble and alkali-soluble resin (hereinafter also simply referred to as “alkali-soluble resin”).

  The positive type image recording layer preferably contains at least two water-insoluble and alkali-soluble resins, and has a phase separation structure of the at least two water-insoluble and alkali-soluble resins.

  In order to form a phase-separated structure, preferably a sea-island structure composed of a dispersed phase and a matrix phase, in the positive image recording layer, alkali-soluble resins serving as a dispersed phase and a dispersion medium (matrix phase) are mutually phased. It is a condition that it does not melt. In a preferred embodiment of the present invention, at least two alkali-soluble resins are selected so as to satisfy this condition.

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

  Preferable alkali-soluble resins used in the present invention include polymers having a structural unit represented by the following general formula (II).

In the general formula (II), X represents a divalent linking group, and R ³¹ represents an alkyl group or an aryl group. x represents 0 or 1;
Here, X is an alkylene group, a linking group derived from acrylic acid, a linking group derived from methacrylic acid, a linking group represented by the following general formula (II-2), or a general formula (II-3). It is preferable to represent the connecting group represented.

In general formula (II-2) or general formula (II-3), x represents 0 or 1 each independently. In General Formula (II-3), R ³² and R ³³ 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. ³⁴ —CH ₂ — (wherein R ³⁴ — represents a hydrogen atom or a substituent similar to those exemplified below as a substituent that can be introduced into an 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 ³¹ represents an alkyl group or an aryl group.
When R ³¹ 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 ³¹ 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 an 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 ³¹ represents an aryl group, preferred is a phenyl group.

When R ³¹ 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 ³⁵ R ³⁶ group (here, R ³⁵ And R ³⁶ each independently represents a hydrogen atom or an alkyl group, preferably a hydrogen atom).
Also, if the polymer having the structural unit represented by the general formula (II) introducing a substituent for adding other functions, can be introduced into the portion of the substituent of the R ^31. 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, preferable substituents introduced into R ³¹ are, as described above, a hydroxy group, an optionally substituted alkoxy group, an optionally substituted hydroxyalkyl group, and — The SO ₂ NR ³⁷ R ³⁸ group, particularly preferred substituents are the hydroxy group and the —SO ₂ NR ³⁷ R ³⁸ group. Here, R ³⁷ and R ³⁸ each independently represent a hydrogen atom or an alkyl group.
In the case where R ³¹ represents a phenyl group, the substituent to be introduced is replaced preferably at the 4-position of the position.
R ³¹ may have one or more optional substituents as described above, but is preferably unsubstituted or has one introduced substituent.

  The polymer having the structural unit represented by the general formula (II) 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 (1), or may be a combination of the structural unit represented by the general formula (II) and another structural unit.

  In all polymers. The structural unit represented by the general formula (II) 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 (II) include, but are not limited to, the polymers described in paragraph No. [0059] of JP-A-2006-208950. is not.

  The weight average molecular weight of the polymer having the structural unit represented by the general formula (II) is preferably 1,000 or more and less than 500,000, the molecular weight is preferably 2,000 or more, more preferably 10,000 or more, Particularly preferred is 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.

  As the alkali-soluble resin in the present invention, a resin not containing the structural unit represented by the general formula (II) can be used. Preferable examples of such resins include phenolic resins. Preferred examples of the phenolic resin include novolak resins, xylenol resins, and resole resins. Among these, novolak resins and xylenol resins are more preferable, and phenol formaldehyde resins, m-cresol formaldehyde resins, and p-cresol formaldehyde resins are particularly preferable. , M- / p-mixed cresol formaldehyde resin, phenol / cresol (any of m-, p-, o-, m- / p-mix, m- / o-mix and o- / p-mix) Mixed formaldehyde resin, 1,2-xylenol, 1,3-xylenol, 1,4-xylenol, 1,5-xylenol, 2,3-xylenol, 2,4-xylenol resin, xylenol / phenol mixed resin, xylenol / novolak Mixed resin, xyleno / 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 and Y ² each independently represent a single bond or CO.

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

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

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

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

  The minimum structural unit having an acidic group selected from the above (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.

  In the copolymer, a compound having an acidic group selected from (1) to (6) to be copolymerized is preferably contained in an amount of 10 mol% or more, 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. . .

  The positive image recording layer preferably contains 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% by mass in the total solid content of the image recording layer, considering the durability of the image recording layer and the sensitivity resulting from the addition amount of the photothermal conversion agent described later. 40 to 95% by mass is more preferable, and 50 to 90% by mass is particularly preferable.

-Phase composition-
As described above, the positive-type 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 It is preferable to form a so-called phase separation structure in which a resin (island portion) having low alkali solubility 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 incompatible with each other from the alkali-soluble resins described above and using them in combination. A preferred blend ratio of the alkali-soluble resin constituting the dispersion medium and the alkali-soluble resin constituting the dispersion medium is 1:99 to 99: 1 from the viewpoint of the formation of the sea-island structure, and a more preferred blend ratio is 5:95 to 95: 5.

  Among the alkali-soluble resins described above, typical combinations of two types of alkali-soluble resins that can form a sea-island structure include novolak resins and acetal polymers, novolak resins and maleimide polymers, novolak resins and acrylic polymers, and the like. be able to.

<Infrared absorber>
The infrared absorber contained in the positive image recording layer has a light absorption region in the infrared region of 700 nm or more, preferably 750 to 1200 nm, and exhibits a light / heat conversion ability by light in this wavelength region. Point to. 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. Furthermore, the dyes represented by the following general formulas (a) to (e) are preferable because they are excellent in photothermal conversion efficiency. In particular, the cyanine dyes represented by the following general formula (a) are used in the image forming material of the present invention. In this case, it is most preferable because it gives a high interaction with the alkali-soluble resin and is excellent in stability and economy.

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

In the above formula, Xa ^- has Za described later ^- is defined as for, Ra represents a hydrogen atom, an alkyl group, ant - represents a group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom . R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the 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), those in which L represents a methine chain having 7 conjugated carbon atoms and those in which R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ all represent hydrogen atoms are easily available. It is preferable from the viewpoint of effect.

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 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 a plurality of R ³³ or R ³⁴ are present, 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.

  Specific examples of the dyes represented by the general formulas (b) to (e) that can be suitably used in the present invention include, for example, paragraphs [0099] to [0114] of JP-A-2006-208950. Examples thereof are exemplified, but are not limited thereto.

  Examples of the pigment include commercially available pigments or color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technical Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), and The pigments described in “Printing Ink Technology” published by CMC (published in 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and polymer-bonded pigments. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isotopic pigments Indolinone pigments, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, and carbon black can be used.

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

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

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

  From the viewpoint of balance between sensitivity and uniformity and durability of the image recording layer, the infrared absorber is 0.01 to 50% by mass, preferably 0.1 to 10%, based on the total solid content constituting the image recording layer. It is preferable to be contained by mass%. In the case of dyes, the ratio is particularly preferably 0.5 to 10% by mass, and in the case of pigments, the ratio is particularly preferably 0.1 to 10% by mass.

<Other ingredients>
In the positive image recording layer, in addition to the above components, various additives can be added as necessary within a range not impairing the effects of the present invention.

  Such additives include, for example, other onium salts, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, polyfunctional amine compounds, etc. to adjust the solubility of the image recording layer, and are soluble in alkaline water. It is preferable to add a so-called dissolution inhibitor that improves the function of preventing dissolution of a polymer (alkali-soluble resin) in a developer. In the state where it is not decomposed, it is preferable to use a substance that substantially lowers the solubility of the alkali-soluble resin in terms of improving the inhibition of dissolution of the image portion 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 .; S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salts, J.M. V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).

  Among these onium salts, diazonium salts and quaternary ammonium salts are particularly preferable from the viewpoints of dissolution inhibition ability and thermal decomposability. In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable. Moreover, as a quaternary ammonium salt, the quaternary ammonium salt shown by (1)-(10) in [Chemical Formula 23] [Chemical Formula 24] described in Unexamined-Japanese-Patent No. 2002-229186 is preferable.

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

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

  Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17474, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

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

  Further, if necessary, a plasticizer may be added to impart flexibility and the like 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.

  In addition, a specific amino compound described in paragraph numbers [0011] to [0027] of JP-A-2006-208950 can be added to the positive image recording layer as necessary.

(Coating solvent and coating method)
The positive type image recording layer 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. Depending on the purpose, 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.

The coating amount of the positive image recording layer (solid content), the coating amount after drying is preferably in the range of ^{0.2g / m 2 ~3.0g / m 2} , 0.5g / m 2 ~2 The range of 0.5 g / m ² is more preferable, and the range of 0.7 g / m to 1.8 g / m is even 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.

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

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

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

(Undercoat layer)
The lithographic printing plate precursor according to the invention has a positive image recording layer and an overcoat layer in this order on a support. If necessary, an undercoat is provided between the support and the positive image recording layer. A layer can be provided. 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 naphthyl phosphonic acid, alkyl phosphonic acid, glycero phosphonic acid, methylene diphosphonic acid and ethylene diphosphonic acid, phenyl phosphoric acid which may have a substituent, naphthyl phosphoric acid, alkyl phosphoric 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. It is salt. Specific examples of the monomer having an onium salt include styrene having a substituent containing an onium group such as a methacrylate having an ammonium group in the side chain, a methacrylamide, a substituent containing an onium group such as a quaternary ammonium group, and the like. It is done.
Furthermore, compounds described in JP-A No. 2000-108538, Japanese Patent Application No. 2002-257484, Japanese Patent Application No. 2003-78699, and the like can be used as necessary.

These undercoat layers can be provided by the following method. That is, a 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 basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image forming material. The coating amount of the undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. Moreover, even if it is larger than 200 mg / m ^2, it is the same.

  The lithographic printing plate precursor according to the invention is usually subjected to image exposure and development. Hereinafter, an image recording method applicable to the planographic printing plate precursor according to the invention will be described.

  The lithographic printing plate precursor according to the invention is image-formed by heat. Specifically, direct image-like recording using a thermal recording head, scanning exposure using an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, and the like are used, but a semiconductor that emits infrared light having a wavelength of 700 to 1200 nm. Exposure by a solid high-power infrared laser such as a laser or a YAG laser is suitable.

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

  The developer that can be applied to the present invention is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. A conventionally known alkaline aqueous solution can be used for the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples thereof include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

  Among the above alkaline aqueous solutions, one of the developing solutions that exert the effect according to the present invention is a so-called one containing an alkali silicate as a base or containing an alkali silicate by mixing a silicon compound with a base. Another more preferable developer, which is an aqueous solution called “silicate developer” having a pH of 12 or more, does not contain an alkali silicate, and contains a non-reducing sugar (an organic compound having a buffering action) and a base. Silicate developer ".

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

  Further, a so-called “non-silicate developer” which does not contain an alkali silicate and contains a non-reducing sugar and a base is more preferable for application to the development of the lithographic printing plate material of the present invention. When 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, or a glycoside in which a reducing group and a non-saccharide are bonded to each other. And sugar alcohols reduced by hydrogenation of saccharides and sugars, both of which can be suitably used in the present invention. In the present invention, non-reducing sugars described in JP-A-8-305039 can be preferably used.

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

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

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

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

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

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

  Specifically, alcohols such as 2,2,3,3-tetrafluoropropanol-1, trifluoroethanol and trichloroethanol, pyridine-2-aldehyde (, aldehydes such as pyridine-4-aldehyde (and the like) , Salicylic acid, 3-hydroxy-2-naphthoic acid, catechol, gallic acid, sulfosalicylic acid, 3,4-dihydroxysulfonic acid, 3,4-dihydroxybenzoic acid, hydroquinone (11.56), pyrogallol, o-, m Compounds having a phenolic hydroxyl group such as-, p-cresol, resorsonol, oximes such as acetoxime, 2-hydroxybenzaldehyde oxime, dimethylglyoxime, ethanediamide dioxime, acetophenone oxime, adenosine, inosine, guanine, cytosine, hypoxanthine , Ki Nucleic acid-related substances such as Nchin, other, diethylaminomethyl acid, benzimidazole, and the like barbituric acid is preferably exemplified.

  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, or improving ink affinity of the printing plate image area. . 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 surface (image recording surface) of the lithographic printing plate precursor after the development treatment may be abraded using a brush or the like.

The lithographic printing plate precursor developed using a developer and a 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 a post-process for use as a lithographic printing plate, these processes 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 that can be used in this case include anionic, cationic, nonionic and amphoteric surfactants. If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added.

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

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

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

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to obtain a lithographic printing plate with a higher printing durability, it is desired. The burning process is performed.
In the case of burning a lithographic printing plate, 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 surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting liquid is dried if necessary and then heated to a high temperature with a burning processor (for example, a burning processor sold by FUJIFILM Corporation: “BP-1300”). . In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

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

  EXAMPLES Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.

[Synthesis Example 1]
<Synthesis of Polymer B-1>
A heating mantle, a thermometer, a stirrer, a water-cooled reflux condenser, a Claisen adapter (Corning 9040 Ace Glass # 4015), 506.62 g of 1,3-dioxolane, 13.56 g Styrene, 25.20 g of glycidyl methacrylate, 4.65 g of monomer A (a monomer having an ethylene glycol group, the following structure), and 0.84 g of dodecanethiol were added. The reaction solution was stirred and heated to reflux at 65 to 70 ° C. for 1 hour under a nitrogen atmosphere. Then, 0.70 g of a 5% (wt / wt) solution of N′N-azobisisobutyronitrile (AIBN) dissolved in 1,3-dioxolane was added every hour for 20 hours. The reaction solution was concentrated to about 1/3 to 1/5 volume under atmospheric pressure and cooled. The obtained solution is poured into cooled methanol while stirring, and after obtaining the reaction product, further washed with cooled methanol, obtained, and heated at 40 ° C. under atmospheric pressure to obtain polymer B-1 (specific polymer). It was. The weight average molecular weight (Mw) of the obtained polymer B-1 was 60,000.

[Synthesis Examples 2 to 5]
<Synthesis of Polymers B-2 to B-5>
In Synthesis Example 1, the amount of styrene, glycidyl methacrylate, a monomer having an ethylene glycol group (monomer A or B), and dodecanethiol used in the composition of the reaction solution used for the synthesis of polymer B-1 is shown in Table 1 below. Except for the amounts described, synthesis of polymers B-2 to B-4, which are specific polymers, and polymer B-5, which is a comparative polymer, were performed according to Synthesis Example 1.

  In Table 1, the epoxy equivalents of the polymers B-1 to B-5 are also shown.

[Examples 1-4, Comparative Examples 1-2]
(Production of support)
An aluminum plate (material: JIS A 1050) with a thickness of 0.3 mm is etched for 10 seconds at a caustic soda concentration of 30 g / l, an aluminum ion concentration of 10 g / l, and a liquid temperature of 60 ° C., washed with running water and washed with 10 g / l nitric acid. After neutralizing and washing with water. This was applied with an electric current of 400 C / dm ² in an aqueous solution having a hydrogen chloride concentration of 15 g / l, an aluminum ion concentration of 10 g / l and a liquid temperature of 30 ° C. using a sinusoidal alternating waveform current under the condition of applied voltage Va = 20V. Electrochemical roughening treatment was carried out in an amount and washed with water. Next, etching treatment was performed for 10 seconds at a caustic soda concentration of 30 g / l, an aluminum ion concentration of 10 g / l, and a liquid temperature of 40 ° C., and washed with running water. Next, desmut treatment was performed in a sulfuric acid aqueous solution having a sulfuric acid concentration of 15% by mass and a liquid temperature of 30 ° C., followed by washing with water. Furthermore, in a 10% by mass sulfuric acid aqueous solution at a liquid temperature of 20 ° C., an anodizing treatment was performed under a condition of a current density of 6 A / dm ² by direct current so that both anodic oxide coatings would be equivalent to 2.5 g / m ² , and washing with water. , Dried. Then, it processed for 10 second at 30 degreeC with the sodium silicate 1.0 mass% aqueous solution, and produced the support body (a) which carried out the hydrophilic process.
When the center line average roughness (Ra) of the support (a) was measured using a needle having a diameter of 2 μm, it was 0.43 μm.

(Formation of undercoat layer)
The following undercoat liquid was applied to the support (a) thus obtained, and dried at 80 ° C. for 30 seconds to provide an undercoat layer. The dry coating amount of the undercoat layer was 17 mg / m ² .

(Undercoat liquid composition)
・ The following compound 0.3g
・ Methanol 100g
・ Water 1g

(Formation of positive image recording 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 make the total coating amount 1.7 g / m ² .

<Coating liquid A>
M-cresol / p-cresol (molar ratio: 60/40, weight average molecular weight: 5,000) 0.20 g
-Polymer (A): Copolymer of N-phenylmaleimide (40 mol%), methacrylamide (35 mol%) and methacrylic acid (25 mol%) 0.80 g
(Weight average molecular weight; 70000)
・ Cyanine dye A (the following structure) 0.017 g
・ 0.003 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.03g
・ Victoria Pure Blue (Dye with BOH counter anion as 1-naphthalenesulfonic acid anion) 0.015g
・ Γ-Butyrolactone 15g
・ Methyl ethyl ketone 5g

(Formation of overcoat layer)
Next, the overcoat layer coating liquid B having the following composition was coated on the positive image recording layer obtained above with a wire bar. After coating, drying was performed at 120 ° C. for 50 seconds to make the total coating amount 1.7 g / m ² . In Comparative Example 2, no overcoat layer was formed.

<Coating liquid B>
-Specific polymers listed in Table 2 or comparative polymers 0.5 g
・ Ethyl violet 0.005g
・ 20 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 5g

(Confirmation of dispersed phase)
Each lithographic printing plate precursor obtained in Examples 1 to 4 was cut with a microtome or the like, and after imparting conductivity to the cross section of the image recording layer, the photograph was observed with a scanning electron microscope (SEM). It was confirmed that a dispersed phase was present in the image recording layers of Examples 1 to 4.

[Evaluation of planographic printing plate precursor]
Next, performance evaluation of the positive type lithographic printing plate precursors of Examples 1 to 4 and Comparative Examples 1 to 2 was performed. The evaluation test was carried out on the sample stored at 25 ° C. for 14 days after the application of the image recording layer.

(Evaluation of sensitivity)
The positive type lithographic printing plate precursors of Examples 1 to 4 and Comparative Examples 1 to 2 were exposed with a Trend setter 800 manufactured by Creo at different beam intensities, and a developer “DT-2” manufactured by Fuji Film Co., Ltd. Development was performed using a water dilution of 1: 8. 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. The results are shown in Table 2.

(Evaluation of development latitude)
The positive lithographic printing plate precursors of Examples 1 to 4 and Comparative Examples 1 to 2 are drawn on the image of a test pattern 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 Film Co., Ltd. with water dilution (1: 9) until the conductivity reached 37 mS / cm, and a finisher manufactured by Fuji Film Co., Ltd. Using a PS processor “LP-940HII” manufactured by FUJIFILM Co., Ltd., which was prepared by diluting FG-1 with water (1: 1), the liquid temperature was kept at 30 ° C. and development was performed for 12 seconds.
Thereafter, an appropriate amount of “DT-2R” diluted with water (1: 9) is added to the developer, the conductivity is adjusted to 39 mS / cm, and a lithographic printing plate precursor in which a test pattern is drawn in an image as before. 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 2.

  As shown in Table 2, the planographic printing plate precursors of Examples having an overcoat layer containing a specific polymer can be recorded with high sensitivity in comparison with the planographic printing plate precursors of Comparative Examples 1 and 2. It can be seen that the development latitude is also excellent.

Claims (2)

On the support, a positive image recording layer containing a water-insoluble and alkali-soluble resin and an infrared absorber, and an overcoat layer containing a polymer represented by the following general formula (I) are provided in this order. A lithographic printing plate precursor characterized by.

[In General Formula (I), R ¹ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. R ² represents a substituted or unsubstituted aliphatic group having an epoxy group. L ¹ represents a single bond or a divalent linking group. R ³ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms. R ⁴ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. L ² represents a divalent linking group. l represents 5-90 mass%. m represents 3-80 mass%. n represents an integer of 1 to 20. ]   The positive image recording layer contains at least two water-insoluble and alkali-soluble resins, and has a phase separation structure with the at least two water-insoluble and alkali-soluble resins. A lithographic printing plate precursor.