JP4762604B2 - Planographic printing plate precursor - Google Patents

Description

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

  Along with the development of image forming technology in recent years, it is possible to directly make a plate without using a film manuscript by scanning a finely focused laser beam on the plate to form a character manuscript, an image manuscript, etc. directly on the plate. Became possible.

  A thermal positive type lithographic printing plate precursor is an image forming material that forms a positive image by causing alkali solubilization of a recording layer by causing photothermal conversion in a heat sensitive layer by laser light irradiation. In such a thermal positive type lithographic printing plate precursor, a subtle change in the intermolecular interaction of the binder in the recording layer due to laser exposure is used as an image forming principle. There is a problem that the alkali-soluble discrimination becomes small and the development latitude (development stability depending on the use conditions) becomes insufficient, and it may not be practically used.

  In order to solve the above problems, an image recording material provided with a recording layer having a multi-layer structure has been proposed for the purpose of widening the development latitude and improving the image forming property of the recording layer to a level that can be practically used. For example, in Patent Document 1, a surface poorly soluble layer with respect to a developer is provided as the uppermost layer of the recording layer, and a layer having a high solubility in the developer is provided as a lower layer, thereby suppressing the developability of the unexposed portion and exposing portions An image forming material is disclosed which has improved developability.

  However, in such an image forming material in which the recording layer has a multi-layer structure, the developability of the exposed portion is improved because the alkali solubility of the lower layer is high, but the image forming property (such as halftone dots and fine lines) of the highlighted portion is improved. There was still room for improvement in the reproducibility of the small area image area.

On the other hand, a positive working composition having a polymer compound composed of polyvinyl alcohol having an acetal unit as a pendant group has been proposed as a technique for improving the solubility of an exposed portion with a single layer structure (for example, a patent) Reference 2). However, when such a composition is applied to a positive-type image-forming material, not only the exposed area but also the unexposed area is highly soluble, and the development latitude is narrowed. There was a problem.
JP 11-218914 A Japanese translation of PCT publication No. 2003-530581

The object of the present invention, which has been made in consideration of the drawbacks of the above-mentioned conventional techniques, is that direct plate-making by scanning exposure based on digital signals from a computer or the like is possible, and it has excellent image formability in highlight areas and development latitude. Is to provide a wide positive type lithographic printing plate precursor.

The present inventors as a result of intensive studies, Oite the recording layer having a multilayer structure, the lower layer of the recording layer having a multilayer structure, by incorporating a polymer compound having a specific structure, that the above object can be achieved The headline and the present invention were completed.
That is, the lithographic printing plate precursor according to the invention comprises a lower layer containing a polymer compound represented by the following general formula (I) (hereinafter referred to as “specific structure polymer” as appropriate) and an alkali-soluble compound having a phenolic hydroxyl group. A positive type comprising a recording layer comprising a resin, a quaternary ammonium salt dissolution inhibitor (excluding those that are dyes and image colorants), and an upper layer containing an infrared absorber A lithographic printing plate precursor.

In general formula (I), R ¹ represents a hydrocarbon group, and R ² represents an aromatic group having a hydroxyl group as a substituent. m = 5-40 mol%, n = 10-60 mol%, o = 1-20 mol%, and p = 5-50 mol%.

Operation of the present invention is not in a clear, under layer of the recording layer of the multilayer structure, in that it contained a specific structure polymer in the unexposed area, the specific structure polymer, contained in the upper layer Cause strong interaction between the alkali-soluble resin and the hydrogen bond, and the layers exhibit strong adhesion, so lateral development near the surface of the lower layer is suppressed, while the interaction is released in the exposed area. Therefore, it is presumed that the image forming property of the highlight portion is improved because the image is rapidly developed. Since the upper surface portion of the unexposed state is a poorly soluble developer layer, combined with excellent solubility in the exposed area, it is estimated that the overall discrimination improved and the development latitude spread. Is done.

According to the present invention, it is possible to provide a positive lithographic printing plate precursor capable of direct plate making by scanning exposure based on a digital signal from a computer or the like, having excellent image forming properties in a highlight portion, and having a wide development latitude. it can.

Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor of the present invention comprises a support containing a lower layer containing the specific structural polymer, an alkali-soluble resin having a phenolic hydroxyl group, and a dissolution inhibitor that is a quaternary ammonium salt (however, a dye and an image colorant) And a top layer containing an infrared absorber, and a positive lithographic printing plate precursor characterized by having a recording layer.

[Recording layer]
Recording layer having a multilayer structure according to the lithographic printing plate precursor of the present invention contains as an essential ingredient a specific structure polymer in the lower layer. In the following, first, the specific structure polymer will be described in detail.

(Specific structure polymer)
In the lithographic printing plate precursor according to the invention, the specific structural polymer used in the recording layer is a polymer compound represented by the following general formula (I). This specific structure polymer is an alkali-soluble polymer.

In general formula (I), R ¹ represents a hydrocarbon group, and R ² represents an aromatic group having a hydroxyl group as a substituent. m is 5 to 40 mol%, n is 10 to 60 mol%, o is 1 to 20 mol%, and p is 5 to 50 mol%.

In the structural unit (a), R ¹ represents a hydrocarbon group, and a linear, branched, or cyclic alkyl group is preferable.
R ¹ is preferably an alkyl group having 1 to 12 carbon atoms (preferably an alkyl group having 3 to 10 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, a butyl group, or pentyl. Group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, t-butyl group , Isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, and 2-norbornyl group, and among them, the number of carbon atoms is 3. 10 to 10 alkyl groups are preferred.
In general formula (I), m which is a copolymerization ratio of the structural unit (a) is 5 to 40 mol%, more preferably 10 to 35 mol%, and more preferably 15 to 30 mol%. Further preferred.
In the polymer compound represented by the general formula (I), the structural unit (a) may contain only the structural unit (a) having the same R ^1, and the structural unit (a) having a different R ¹ May contain a plurality of types.

In the structural unit (b), R ² represents an aromatic group having a hydroxyl group as a substituent. Examples of the aromatic ring contained in R ² include a benzene ring, a naphthalene ring, and an anthracene ring.
R ² essentially has a hydroxyl group as a substituent, but may have another substituent other than the hydroxyl group. Examples of the substituent that can be introduced include a monovalent nonmetallic atomic group excluding hydrogen. Used. Preferred examples include a halogen atom (—F, —Br, —C1, —I), a hydroxyl group, an alkoxy group, an aryloxy group, a mercapto group, an alkylthio group, an arylthio group, an alkyldithio group, an aryldithio group, an amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy Group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group , Acylamino group, N-alkyl acyla Group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-arylureido group, N ′, N′-diarylureido group, N′- Alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido group, N'-alkyl-N-arylureido group, N ', N'- Dialkyl-N-alkylureido group, N ′, N′-dialkyl-N-arylureido group, N′-aryl-N-alkylureido group, N′-aryl-N-arylureido group, N ′, N′- Diaryl-N-alkylureido group, N ′, N′-diaryl-N-arylureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl- -Arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, carboxyl group, and its conjugate base group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfo group (-S O ₃ H) and its conjugate base (hereinafter referred to as “sulfonate group”). ), Alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group , N- alkyl -N- arylsulfamoyl group, N- acylsulfamoyl group and a conjugate base group, N- alkylsulfonylsulfamoyl group (representing -SO ₂ NHSO ₂ R, R is an alkyl group.) and a conjugated base group, N- aryl sulfonylsulfamoyl group (-SO ₂ NHSO ₂ A , Ar represents an aryl group) and a conjugated base group, N- alkylsulfonylcarbamoyl group (-CONHSO ₂ R, R represents an alkyl group) and a conjugated base group, N- ants -.. Rusuru Honi carbamoyl group ( —CONHSO ₂ Ar, Ar represents an aryl group) and its conjugate base group, alkoxysilyl group (—Si (OR) ₃ , R represents an alkyl group), aryloxysilyl group (—Si (OAr) ₃ , Ar represents an aryl group), a hydroxysilyl group (—Si (OH) ₃ ) and its conjugate base group, a phosphono group (—PO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as “phosphonate group”). ), dialkylphosphono group (-PO ₃ R ^2, R represents an alkyl group.), diarylphosphono group (-PO ₃ Ar _2, Ar represents an aryl group.), alkyl Riruhosuhono group _{(-PO 3 (R) (Ar} ), R is an alkyl group, Ar represents an aryl group.), Monoalkyl phosphono group _{(-PO 3 H (R),} R represents an alkyl group.) And The conjugated base group (hereinafter referred to as “alkylphosphonate group”), the monoarylphosphono group (—PO ₃ H (Ar), Ar represents an aryl group) and the conjugated base group (hereinafter referred to as “arylphosphonate”). Nato group ”), phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as“ phosphonatoxy group ”), dialkylphosphonooxy group (—OPO ₃ R ₂ , R represents an alkyl group) ), A diarylphosphonooxy group (—OPO ₃ Ar ₂ , Ar represents an aryl group). ), An alkylarylphosphonooxy group (—OPO ₃ (R) (Ar), R represents an alkyl group, Ar represents an aryl group), a monoalkylphosphonooxy group (—OPO ₃ H (R), R is Represents an alkyl group) and its conjugate base group, monoarylphosphonooxy group (—OPO ₃ H (Ar), Ar represents an aryl group) and its conjugate base group, cyano group, nitro group, aryl group ( For example, phenyl group, biphenyl group, naphthyl group, tolyl group, xylyl group, mesityl group, cumenyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group , Phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenyl Ophenyl group, methylaminophenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxycarbonylphenyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group, nitrophenyl group , Cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl group, phosphonatophenyl group, etc.), alkenyl group (for example, vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group) , 2-chloro-1-ethenyl group, etc.), alkynyl group (for example, ethynyl group, 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group, phenylethynyl group, etc.), acyl group. (R ⁷ C -;. The R ^7, may be mentioned hydrogen atom)), and the like.

  In the general formula (I), n, which is a copolymerization ratio of the structural unit (b), is 10 to 60 mol%, more preferably 20 to 55 mol%, and further preferably 30 to 50 mol%. preferable.

R ² is preferably a group shown below.

In the above formula, R ³ represents —OH. R ⁴ represents —OH, —OCH ₃ , —Br, or —OCH ₂ —C≡CH ₃ . R ⁵ represents —Br or —NO ₂ .

In the polymer compound represented by the general formula (I), the structural unit (b) may contain only the structural unit (b) having the same R ^2, and the structural unit (b) having a different R ¹ May contain multiple types.

In general formula (I), o which is a copolymerization ratio of the structural unit (c) is 1 to 20 mol%, more preferably 2 to 15 mol%, and further preferably 3 to 10 mol%. preferable.
Moreover, p which is a copolymerization ratio of a structural unit (d) is 5-50 mol%, It is more preferable that it is 10-45 mol%, It is still more preferable that it is 15-40 mol%.

  The polymer compound represented by the general formula (I) may contain other structural units other than the structural units (a), (b), (c), and (d).

  Among the polymer compounds represented by the general formula (I), the specific structure polymer in the present invention is more preferably a polymer compound represented by the following general formula (II).

In the general formula (II), the structural units (a), (b), (c), and (d) are synonymous with the structural units (a), (b), (c), and (d) in the general formula (I), The preferable range is also the same.
In the structural unit (e), R ⁶ represents — (CH ₂ ) _X COOH, —C≡CH, or a group shown below. X represents an integer of 1 or more, preferably an integer of 1 to 12. q is 0 to 20 mol%.

In the above formula, R ⁷ represents —COOH, — (CH ₂ ) _X COOH, —O— (CH ₂ ) _X COOH. X represents an integer of 1 or more, preferably an integer of 1 to 12.

In general formula (II), q which is a copolymerization ratio of the structural unit (e) is 0 to 20 mol%, more preferably 3 to 17 mol%, and more preferably 5 to 15 mol%. Further preferred.
In the polymer compound represented by the general formula (II), the structural unit (e) may contain only the structural unit (e) having the same R ^6, and the structural unit (e) having a different R ⁶ May contain a plurality of types.

The content of the specific structure polymer in the recording layer is 10 to 99% by mass, preferably 30 to 95% by mass, preferably 50 to 90% by mass when contained in any layer constituting the recording layer. is there.
As content of a specific structure polymer, when making it contain in a lower layer, it is 10-99 mass% with respect to the total solid which comprises a lower layer, Preferably it is 30-95 mass%, 50-90 mass%. Moreover, when making it contain in an upper layer (uppermost layer), it is 1-70 mass% with respect to the total solid which comprises an uppermost layer, Preferably it is 3-60 mass%, More preferably, it is 5-50 mass%.

  The recording layer may contain an alkali-soluble resin other than the specific structure polymer. As other alkali-soluble resin, what is described in description of the upper layer mentioned later can be applied. When the specific structure polymer and another alkali-soluble resin are used in combination, the content ratio is preferably 1:99 to 99: 1 and more preferably 10:90 to 95: 5 in terms of mass ratio.

  The alkali-soluble resin other than the specific structure polymer that can be contained in the recording layer according to the planographic printing plate precursor of the invention will be described.

(Alkali-soluble resin)
In the present invention, the alkali-soluble resin contained in the recording layer is not particularly limited. However, the alkali-soluble resin having a phenolic hydroxyl group is preferable because of its high interaction with the specific structure polymer and relatively high discrimination of the resin itself. It is preferably a soluble resin, and more preferably a novolac resin.

  Examples of the alkali-soluble resin having a phenolic hydroxyl group contained in the upper layer include (1) those having an acidic group represented by a phenol group (—Ar—OH) in the main chain and / or side chain of the polymer. It is done. Here, Ar represents a divalent aryl linking group which may have a substituent.

Examples of such alkali-soluble resins include the following resins.
For example, a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, a condensation polymer of m- / p-mixed cresol and formaldehyde, phenol And a novolak resin such as a condensation polymer of formaldehyde and cresol (which may be any of m-, p-, or m- / p-mixed) and formaldehyde, and a condensation polymer of pyrogallol and acetone. Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned. Alternatively, a copolymer obtained by copolymerizing a compound having a phenol group in the side chain can also be used.

  Examples of the compound having a phenol group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.

  Examples of the novolak resin suitably contained in the recording layer according to the present invention include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m Any of-, p-, o-, m- / p-mixing, m- / o-mixing, and o- / p-mixing.) Mixed formaldehyde resins. These may be used alone or in combination of two or more.

  These novolak resins preferably have a weight average molecular weight of 1,500 or more and a number average molecular weight of 300 or more. 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. .

Preferable alkali-soluble resins other than the alkali-soluble resin having a phenolic hydroxyl group include those having an acidic group listed in the following (2) to (6) in the polymer main chain and / or side chain.
(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 (2) 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 (2) to (6) above, (2) a sulfonamide group and (3) an alkali-soluble resin having an active imide group are preferable, and in particular, (2) a sulfonamide group. Alkali-soluble resins having the above are most preferable from the viewpoint of sufficiently ensuring solubility in an alkaline developer, development latitude, and film strength.

  (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 general formula (i) to general formula (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.

  In the present invention, among the compounds represented by the general formulas (i) to (v), in particular, m-aminosulfonylphenyl methacrylate, 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) that constitutes the alkali-soluble resin used in the lithographic printing plate precursor according to the present invention is not particularly limited to one type, and has the same acidity. Two or more minimum structural units having a group, or two or more minimum structural units having different acidic groups copolymerized may be used. In the case of an alkali-soluble resin having a phenolic hydroxyl group, the acidic group represented by (1) phenol group (—Ar—OH) is an essential structural unit.

  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.

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

  Examples of the alkali-soluble resin other than the above include modified novolak resins having a structural unit represented by the following general formula (1).

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

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

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

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

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

  In the present invention, in the film formed using the modified phenolic resin, mainly the above-mentioned lone pair of hydrogen bonding sites and hydrogen atoms capable of hydrogen bonding form thermally reversible hydrogen bonds. Here, the hydrogen bond is not formed between the sites in the same substituent, but is formed between another specific substituent existing in the film. Hereafter, the said coupling | bonding is demonstrated concretely, taking the specific substituent of the specific example (A) of the modified phenolic resin mentioned later as an example.

In the reaction formula 1, the sites corresponding to the lone pair binding site are (= O) and (= N-), and the hydrogen atom corresponding to the hydrogen atom capable of hydrogen bonding is (> N-H). (-H). Since the specific substituent of Reaction Formula 1 has two unshared electron pair binding sites and two hydrogen atoms capable of hydrogen bonding, a total of four hydrogen bonds are formed. In the present invention, it is sufficient that two or more hydrogen bonds are formed. Therefore, one specific substituent has one or more lone pair of hydrogen atoms and one or more hydrogen atoms capable of hydrogen bonding. It will be good.
Thus, since the specific substituent according to the present invention forms two or more hydrogen bonds with other specific substituents, a stable interaction that does not cause a rotational movement of the molecule is formed, which is excellent. It is considered that an effect of improving chemical resistance is obtained. Since this hydrogen bond is thermally reversible, when used as a recording layer component, it is easily released by laser exposure or the like during image formation, and an exposed portion (non-image portion) is removed by development.

  As the modified phenolic resin, any one having a phenolic hydroxyl group in the molecule in addition to the structural unit represented by the general formula (1) can be used. Especially, what introduce | transduced the structural unit represented by the said General formula (1) to a novolak resin, a resole resin, polyhydroxystyrene resin, etc. is preferable.

  In the present invention, it is necessary to have a phenolic hydroxyl group in the molecule together with the general formula (1). The phenolic hydroxyl group must be introduced into the molecule as a structural unit represented by the following general formula (2). The (A) modified phenolic resin of the present invention is particularly composed of the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) as follows. Most preferably, it is a resin.

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

As a copolymerization ratio of the structural unit represented by the general formula (1) (structural unit (1)) and the structural unit represented by the general formula (2) (structural unit (2)), chemical resistance From the viewpoint of sensitivity, the structural unit (1): structural unit (2) is preferably in the range of 1:99 to 95: 5, and more preferably in the range of 2:98 to 90:10. Most preferably, it is in the range of 3:97 to 80:20. The modified phenolic resin may have a copolymer component other than the structural unit (1) and the structural unit (2).
Specific examples of the structural unit of the modified phenolic resin according to the present invention are shown below, but the present invention is not limited thereto.

(Synthesis method)
The method for synthesizing the modified phenolic resin according to the present invention is not particularly limited. For example, a phenol resin for substituting a part of a hydroxyl group with a specific substituent is used in a solvent with Sn metal as a catalyst. It can be produced by reacting with an isocyanate group (nucleophilic addition reaction) to form a urethane bond.

The nucleophilic addition reaction between the phenoxide of a novolak-type phenol resin for substituting a part of the hydroxyl group with a specific substituent and the isocyanate group-containing compound can be performed as follows. That is, the total weight of the novolak-type phenol resin for substituting a part of the hydroxyl group with a specific functional group is dissolved in a solvent so as to have a concentration of 20 to 80% by mass (preferably 30 to 70% by mass). With respect to the total number of moles of hydroxyl groups of the novolak-type phenol resin, the isocyanate group-containing compound is added so that the mole ratio thereof is a mole ratio to be substituted with a specific functional group, and further, the mole of the isocyanate group-containing compound using Sn metal as a catalyst. It is added under temperature conditions in the range of 10 ° C. to 200 ° C. so that the molar ratio to the number is 0.5 to 5.0% (preferably 1.0 to 2.5), and the number is maintained while maintaining the temperature range. This can be done by stirring for a period of time. In addition, it is preferable that reaction temperature is the range of 20 to 150 degreeC, and it is more preferable that it is the range of 20 to 100 degreeC.
In this case, examples of the solvent used in the above reaction include chloroform, dichloromethane, dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), dimethyl ether (DME), tetrahydrofuran (THF), and the like. Tetrahydrofuran (THF) is preferably used.
As the Sn metal, dibutyltin dilaurate is preferably used.

  The modified phenolic resin according to the present invention preferably has a weight average molecular weight of 200 or more and a number average molecular weight of 200 or more. More preferably, the weight average molecular weight is 500 to 30,000, 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.

As the alkali-soluble resin contained in the recording layer according to the present invention, one or a combination of two or more kinds may be used as long as it contains an alkali-soluble resin having a phenolic hydroxyl group as an essential component.
The content of the alkali-soluble resin is 30 to 99% by mass, preferably 40 to 95% by mass, particularly 40 to 95% by mass in the total solid sentence constituting the upper layer, when it is contained in the upper layer from the viewpoint of film forming property, durability and sensitivity. Preferably, it is used in an addition amount of 50 to 90% by mass, and when it is contained in the lower layer, it is 1 to 90% by mass, preferably 5 to 80% by mass, particularly preferably 10 to 70% by mass in the total solid sentence constituting the lower layer. %.
The content ratio when the alkali-soluble resin having a phenolic hydroxyl group and another alkali-soluble resin are used in combination is preferably 1:99 to 99: 1 in terms of mass ratio, and 10:90 to 95: 5. Is more preferable.

(Infrared absorber)
The infrared absorbent according to the present invention refers to a substance that has a light absorption region in the infrared region of 700 nm or more, preferably 750 to 1200 nm, and exhibits light / heat conversion ability by light in this wavelength region. Specifically, various dyes or pigments that absorb light in the above wavelength range and generate heat can be used.

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

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

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

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

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Further, the dyes represented by the following general formulas (a) to (e) are preferable because they are excellent in photothermal conversion efficiency. Particularly, the cyanine dye represented by the following general formula (a) is used in the image forming material according to 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. Preferred substituents include hydrocarbon groups having 12 or less carbon atoms, halogen atoms, and alkoxy groups having 12 or less carbon atoms. 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 its structure and neutralization of charge is not necessary. Preferred Za ⁻ is halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, and sulfonate ion, particularly preferably perchloric acid, from the storage stability of the recording layer coating solution. Ions, hexafluorophosphate 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 the 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. From the viewpoint of the effect.

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

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

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

In general formula (d), R ²⁹ to R ³¹ each independently represents 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 the general formula (e), R ^{35 to} R ⁵⁰ each independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a hydroxyl group, a carbonyl group, a thio group, or a sulfonyl group. Group, a sulfinyl group, an oxy group, an amino group, an onium salt structure, and when a substituent can be introduced, it may further have a substituent. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein are IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements can be mentioned, among which copper, magnesium, iron, zinc, cobalt, aluminum, titanium, and vanadium are preferable.

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

  Examples of the pigment include commercially available pigments or color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology 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 Publishing, 1984) can be used.

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

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

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

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

  These pigments or dyes are 0.01 to 50% by mass, preferably 0.1 to 10% by mass, based on the total solid content constituting the recording layer, from the viewpoints of sensitivity, recording layer uniformity and durability. . In particular, in the case of a dye, it is preferably contained in a proportion of 0.5 to 10% by mass, and in the case of a pigment, it is preferably contained in a proportion of 0.1 to 10% by mass.

-Recording layer configuration-
The specific structure polymer, alkali-soluble resin, or infrared absorber contained in the recording layer of the present invention may be contained in any of the recording layers having a multilayer structure. Specific embodiments of the recording layer structure include, for example, i) an embodiment containing an alkali-soluble resin and an infrared absorber in the lower layer, and a specific structure polymer and an alkali-soluble resin in the uppermost layer, and ii) an alkali-soluble resin and infrared in the lower layer. An embodiment containing an absorbent and a specific structure polymer in the uppermost layer, iii) An embodiment containing a specific structure polymer in the lower layer and an alkali-soluble resin and an infrared absorber in the uppermost layer, iv) A specific structure polymer and an infrared absorber in the lower layer However, it is not limited to this, for example, in which the uppermost layer contains an alkali-soluble resin and an infrared absorber.
Among the recording layer configuration examples described above, the embodiments of iii) and iv), that is, the embodiment containing a specific structure polymer (and an infrared absorber) in the lower layer and an alkali-soluble resin and an infrared absorber in the uppermost layer are preferable. Furthermore, when the alkali-soluble resin contained in the uppermost layer is an alkali-soluble resin having a phenolic hydroxyl group, the interaction between the layers is remarkably exhibited, so that the effect of the present invention is further improved.
The number of layers constituting the recording layer in the present invention is not particularly limited.

(Other ingredients)
Various additives can be further added to the upper layer as necessary.
For example, in order to adjust the solubility of the recording layer, when other onium salts, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, polyfunctional amine compounds, etc. are added, development of an alkali water-soluble polymer (alkali-soluble resin) is performed. It is preferable to add a so-called dissolution inhibitor that improves the dissolution inhibition function in the liquid, and among them, onium salts, o-quinonediazide compounds, sulfonic acid alkyl esters and the like are thermally decomposable, and in a state where they are not decomposed, alkali-soluble resins It is preferable to use a substance that substantially lowers the solubility in terms of improving the solubility of the image area in the developer. In the present invention, it is necessary that the upper layer contains a dissolution inhibitor that is a quaternary ammonium salt. However, the dissolution inhibitor that is the quaternary ammonium salt does not include those that are dyes and image colorants.

Preferred examples of the onium salt used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salts, J.M. V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).
Among these onium salts, diazonium salts and quaternary ammonium salts are particularly preferable from the viewpoints of dissolution inhibition ability and thermal decomposability. In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable. Moreover, as a quaternary ammonium salt, the quaternary ammonium salt shown by (1)-(10) in [Chemical 5] [Chemical 6] 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 lithographic printing plate according to 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 described later can also be used in the positive recording layer of the present invention.
Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride described in US Pat. No. 4,115,128, Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 “-Trihydroxytriphenylmethane, 4,4 ′, 3”, 4 ”-tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane, 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, in the present invention, in order to broaden the stability of the processing with respect to the development conditions, nonionic surfactants such as those described in JP-A Nos. 62-251740 and 3-208514 are disclosed. Amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149, siloxane compounds as described in EP950517, and JP-A-11-288093. Such a fluorine-containing monomer copolymer can be added.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.).
The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and the amphoteric surfactant in the photosensitive composition is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

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 recording layer.

  Furthermore, a plasticizer is added to the uppermost layer of the recording layer in the lithographic printing plate precursor according to the present invention, if necessary, for imparting flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

[Formation of recording layer]
The recording layer according to the present invention can be formed by dissolving each component constituting the recording layer having a multilayer structure in a solvent, applying the solution on a suitable support, and drying.
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, methylbutyrolactone, and toluene. However, it is not limited to this. These solvents are used alone or in combination.
The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.
The coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but generally the coating amount after drying is 0.1 to 5.0 g / m ² as the lower layer. 0.2 to 3.0 g / m ² is more preferable. As the upper layer (uppermost layer), preferably the amount to be 0.01 to 5.0 mg / m ^2, more preferably the amount to be 0.05 to 2.0 mg / m ^2.

  Various methods can be used for applying the recording layer coating liquid. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating, etc. Can be mentioned. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the recording layer may deteriorate.

As a method of separately forming a recording layer having a multilayer structure (for example, an upper layer and a lower layer), for example, a method using a difference in solvent solubility between a component contained in the lower layer and a component contained in the upper layer, or Examples include a method of rapidly drying and removing the solvent after applying the upper layer.
Hereinafter, although the method of apply | coating two layers separately is demonstrated to an example, it is not limited to these methods.

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

  Next, after applying the second layer (upper layer), as a method of drying the solvent very quickly, a method of blowing high-pressure air from a slit nozzle installed substantially perpendicular to the running direction of the web, heating with steam, etc. The method of giving thermal energy as conduction heat from the lower surface of the web from the roll (heating roll) supplied inside the medium, or a combination of these methods can be mentioned.

  Further, in the recording layer according to the present invention, a surfactant for improving the coating property, for example, a fluorosurfactant as described in JP-A-62-170950 is added. be able to. A preferable addition amount is 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass in the total solid content of the recording layer.

[Support]
The support according to the present invention is not particularly limited as long as it is a dimensionally stable plate-like material and satisfies physical properties such as required strength and flexibility. For example, paper, plastic (for example, Paper laminated with 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.), paper laminated with a metal such as those mentioned above, or plastic film, or the like.

  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 is provided with a recording layer as described above on a support. If necessary, an undercoat layer may be provided between the support and the lower layer of the recording layer. it can.
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.
Further, in the unexposed area, the image recording layer itself that is impermeable to the alkali developer functions as a protective layer for the undercoat layer, so that the development stability is improved and the discrimination is excellent. It is considered that an image can be formed and stability over time is secured.
Furthermore, since the undercoat layer is a layer mainly composed of an alkali-soluble polymer and has a very good solubility in a developer, by providing such an undercoat layer adjacent to the support. For example, even when a developer with reduced activity is used, no residual film or the like is generated when the components of the photosensitive layer whose dissolution inhibiting ability is released by exposure are dissolved and dispersed in the developer. The exposed part is quickly removed. This is considered to contribute to the improvement of developability. For these reasons, the primer layer is considered useful.

  Various organic compounds are used as the undercoat layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylene which may have a substituent Organic phosphonic acids such as diphosphonic acid and ethylenediphosphonic acid, phenylphosphonic acid optionally having substituents, organic phosphoric acid such as naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid, phenyl optionally having substituents Selected from organic phosphinic acids such as phosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochlorides of amines having hydroxy groups such as hydrochloride of triethanolamine 2 or more It may be used in.

  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.

In the above formula, 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, or a substituted aryl. Represents a group, —OR ¹⁴ , —COOR ¹⁵ , —CONHR ¹⁶ , —COR ¹⁷ or —CN, or R ¹² and R ¹³ may combine to form a ring, and R ^{14 to} R ¹⁷ are each independently 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, It represents an aryl group or a substituted aryl group, or R ¹⁸ and R ¹⁹ may combine to form a ring, and m represents an integer of 1 to 3.

Further, examples of suitable undercoat layer components of the lithographic printing plate according to the present invention include polymer compounds having a component having an acid group and a component having an onium group described in JP-A No. 2000-241962. Can do. Specific examples include a copolymer of a monomer having an acid group and a monomer having an onium group. The acid group is preferably an acid group having an acid dissociation index (pKa) of 7 or more, more preferably —COOH, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , — CONHSO ₂ — or —SO ₂ NHSO ₂ —, particularly preferably —COOH. Specific examples of the monomer having an acid group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, and styrene having the acid group. Preferred as the onium salt is an onium group 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 recording material. The coverage of the undercoat layer, from the viewpoint of printing durability, 2 to 200 mg / m ² are suitable, and preferably from 5 to 100 mg / m ^2.

[Prepress processing of lithographic printing plate precursor]
(exposure)
The planographic printing plate precursor of the present 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 .

(developing)
The developer that can be applied to the lithographic printing plate precursor according to the 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 as 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.

  In addition, 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 a lithographic printing plate precursor according to 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 from the viewpoint of promoting high concentration and availability.

  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 Acids Solution issued 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.

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

  The lithographic printing plate developed using the developer and the replenisher is post-treated with a desensitizing solution containing washing water, a rinsing solution containing a surfactant or the like, gum arabic or a starch derivative. As post-processing, 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 include anionic, cationic, nonionic and amphoteric surfactants. If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added.
The printing plate developed using the developer and the replenisher is post-treated with water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment of the printing plate precursor according to the present invention, these treatments can be used in various combinations.

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

  In the present invention, when there is an unnecessary image portion (for example, a film edge mark of the original film) on the planographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming. 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 make a lithographic printing plate with a higher printing durability, if desired, 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 solution is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). The In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

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

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

[Examples 1 to 8, Comparative Example 1]
(Production of support)
The support body was produced by processing through the process shown below using a JIS-A-1050 aluminum plate with a thickness of 0.3 mm.

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

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

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

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

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

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

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

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

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

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

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

<Support C>
A support C was prepared by sequentially performing the steps except that the steps (a), (g), (h), and (i) were omitted.
<Support D>
Of the above steps, the steps (a) and (d) (e) (f) are omitted except that the steps are performed in order, and the total amount of electricity in the step (g) is 450 C / dm ² for support. Body D was prepared.
Supports A, B, C and D obtained as described above were subsequently subjected to the following hydrophilic treatment and undercoating treatment.

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

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

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

(Formation of recording layer)
Next, the lower layer coating solution A having the following composition was applied to the support with the undercoat layer obtained above with a wire bar, and then dried in a drying oven at 140 ° C. for 50 seconds to obtain a coating amount of 0.85 g. / M ² .
The upper layer coating liquid B having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying at 140 ° C. for 60 seconds was performed to obtain positive lithographic printing plate precursors of Examples 1 to 8 and Comparative Example 1 at a total coating amount of 1.1 g / m ² .

<Coating liquid A for lower layer>
-Specific structure polymer shown in Table 1. 2.13 g
・ Cyanine dye X (the following structure) 0.134 g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.19g
・ 0.008 g of p-toluenesulfonic acid
2-methoxy-4- (N-phenylamino)
Benzenediazonium hexafluorophosphate 0.032 g
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.023g
・ Γ-Butyrolactone 13.16g
・ Methyl ethyl ketone 25.39g
・ 1-methoxy-2-propanol 12.95 g

<Upper layer coating solution B>
・ 0.341 g of alkali-soluble resin shown in Table 1
・ Cyanine dye X (the following structure) 0.019 g
-The following structural polymer A / MEK 30% solution (the following structure) 0.14 g
・ Quaternary ammonium salt (the following structure) 0.004g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.004g
-Fluorosurfactant (Megafac F-781, manufactured by Dainippon Ink & Chemicals, Inc.) 0.001g
・ Methyl ethyl ketone 2.63g
・ 1-methoxy-2-propanol 5.27g

[Comparative Example 2]
After applying the recording layer coating liquid C having the following composition to the support with the undercoat obtained by the same method as in Examples 1 to 8 with a wire bar, it was dried in a drying oven at 140 ° C. for 100 seconds, A positive lithographic printing plate precursor of Comparative Example 2 in which the coating amount was 1.80 g / m ² and a single recording layer was formed was obtained.

<Coating liquid C for recording layer>
・ Specific structure polymer shown in Table 1 0.75 g
-Alkali-soluble resin 0.25g shown in Table 1
・ Tetrahydrophthalic anhydride 0.03g
・ Cyanine dye X (the above structure) 0.017 g
0.015 g of a dye having 1-naphthalenesulfonic acid anion as a counter ion of Victoria Pure Blue BOH
・ Fluorine-based surfactant (Megafac F-177, manufactured by Dainippon Ink & Chemicals, Inc.) 0.05 g
・ Γ-Butyrolactone 10g
・ Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

[Examples 9 and 10]
After applying the lower layer coating liquid D having the following composition to the support with an undercoat obtained by the same method as in Examples 1 to 8 with a wire bar, the coating amount was dried in a drying oven at 140 ° C. for 50 seconds. Was set to 0.85 g / m ² .
The upper layer coating solution E having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying at 140 ° C. for 60 seconds was performed to obtain positive lithographic printing plate precursors of Examples 9 and 10 at a total coating amount of 1.1 g / m ² .

<Lower layer coating solution D>
N- (4-aminosulfonylphenyl)
Methacrylamide / acrylonitrile / methyl methacrylate (36/34/30, weight average molecular weight 50,000) 2.13 g
・ Cyanine dye X (the above structure) 0.134 g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.19g
・ 0.008 g of p-toluenesulfonic acid
2-methoxy-4- (N-phenylamino)
Benzenediazonium hexafluorophosphate 0.032 g
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.023g
・ Γ-Butyrolactone 13.16g
・ Methyl ethyl ketone 25.39g
・ 1-methoxy-2-propanol 12.95 g

<Upper coating liquid E>
・ Specific structure polymer shown in Table 1 0.034 g
-Alkali-soluble resin 0.307g shown in Table 1
・ Cyanine dye X (the above structure) 0.019 g
-0.14 g of the above structural polymer A / MEK 30% solution (the above structure)
・ Quaternary ammonium salt (the above structure) 0.004g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.004g
-Fluorosurfactant (Megafac F-781, manufactured by Dainippon Ink & Chemicals, Inc.) 0.001g
・ Methyl ethyl ketone 2.63g
・ 1-methoxy-2-propanol 5.27g

[Comparative Example 3]
An upper layer coating solution F having the following composition was applied to a support with an undercoat layer obtained in the same manner as in Examples 9 and 10 with a wire bar. After coating, drying at 140 ° C. for 60 seconds was performed to obtain a positive planographic printing plate precursor of Comparative Example 3 with a total coating amount of 1.1 g / m ² .

<Upper layer coating solution F >
・ 0.341 g of alkali-soluble resin shown in Table 1
・ Cyanine dye X (the above structure) 0.019 g
-0.14 g of the above structural polymer A / MEK 30% solution (the above structure)
・ Quaternary ammonium salt (the above structure) 0.004g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.004g
-Fluorosurfactant (Megafac F-781, manufactured by Dainippon Ink & Chemicals, Inc.) 0.001g
・ Methyl ethyl ketone 2.63g
・ 1-methoxy-2-propanol 5.27g

[Evaluation of lithographic printing plate precursor]
Next, performance evaluation of the positive planographic printing plate precursors of Examples 1 to 10 and Comparative Examples 1 to 3 was performed. The evaluation test was carried out for the samples stored at 25 ° C. for 14 days after the lower layer and the upper layer were coated (for the second comparative example, after the single recording layer was coated).

(Evaluation of development latitude)
The obtained lithographic printing plate precursor was drawn (exposed) into an image of a test pattern on a Trendsetter 800 manufactured by Creo under the conditions of an exposure amount of 10.0 W and a drum rotation speed of 250 rpm.
Next, a solution in which carbon dioxide gas was blown into the developer DT-2R manufactured by Fuji Photo Film Co., Ltd. in water (1: 9) until the electrical conductivity reached 37 mS / cm, and a finisher manufactured by Fuji Photo Film Co., Ltd. Development was carried out using a PS processor LP-940HII manufactured by Fuji Photo Film Co., Ltd., in which a FG-1 aqueous dilution (1: 1) solution was charged and the liquid temperature was kept at 30 ° C., and the development time was 12 seconds. Thereafter, an appropriate amount of DT-2R diluted with water (1: 9) was added to the developer, the conductivity was adjusted to 39 mS / cm, and the lithographic printing plate precursor in which the test pattern was drawn in an image shape as before was developed. . Further, the electrical conductivity was increased by 2 mS / cm, and this operation was continued until a film loss due to image development was observed remarkably.

In the developed plates of Examples and Comparative Examples after development, the plates developed with each conductivity were checked with a magnifier of 50 times to see whether there was any stain or coloring due to poorly developed non-image area residual film. The conductivity of the developer that could be developed was determined. Next, the electric conductivity at the limit at which development suppression of the solid portion due to development is maintained, specifically, the image density of the solid portion before development is measured with a GRETAG reflection densitometer D196 (manufactured by GretagMacbeth), and this image is measured. The electric conductivity of the developer having a solid portion having an image density of 0.10 or less from the density was determined.
The development latitude was defined as the electric conductivity of the developer that was successfully developed and the limit of the electric conductivity at which the solid portion development was maintained. The larger this value, the wider the development latitude. The results are shown in Table 1.

(Evaluation of image formation in highlight area)
The obtained lithographic printing plate precursor is exposed to a Trend setter 800 manufactured by Creo using a Staccato10 screen (manufactured by Creo) by exposing a halftone dot having an area ratio of 50% under the conditions of an exposure amount of 10.0 W and a drum rotation speed of 250 rpm. Thereafter, the image forming property (reproducibility of the minute area image portion) of the highlight portion was measured with DMS910 (manufactured by TECHKON). Here, it is shown that the image formability of the highlight portion is better as the output area ratio is closer to 50%. The results are shown in Table 1.

  The details of “specific structure polymer” and “alkali-soluble resin” in Table 1 are as follows.

[Specific structure polymer]

Specific polymer (a): (a / b / c / d / e = 36/37/2/25/0; weight average molecular weight: 16000)
R ¹ = n-butyl group R ² = 4-hydroxybenzyl group / specific structure polymer (b): (a / b / c / d / e = 12/49/17/22/0; weight average molecular weight: 14000)
R ¹ = n-butyl group R ² = 3-hydroxybenzyl group / specific structure polymer (c): (a / b / c / d / e = 30/41/2/20/9; weight average molecular weight: 18000)
R ¹ = n-butyl group R ² = 2-hydroxybenzyl group R ⁶ = glyoxylic acid group / specific structure polymer (d): (a / b / c / d / e = 21/43/2/24/10; (Weight average molecular weight: 16000)
R ¹ = n-butyl group R ² = 3-hydroxybenzyl group R ⁶ = propargyl group / specific structure polymer (e): (a / b / c / d / e = 38/42/2/18/0; weight (Average molecular weight: 18000)
R ¹ = n-butyl group R ² = 2-hydroxybenzyl group / specific structure polymer (f): (a / b / c / d / e = 25/38/12/26/0; weight average molecular weight: 16000)
R ¹ = n-butyl group R ² = 4-hydroxybenzyl group / specific structure polymer (g): (a / b / c / d / e = 16/10/12/44/18; weight average molecular weight: 18000)
R ¹ = n-isobarrel group R ² = 2-hydroxybenzyl group R ⁶ = 4-formylphenoxyacetic acid group / specific structure polymer (h): (a / b / c / d / e = 14/44/2/40 / 0; weight average molecular weight: 16000)
R ¹ = n-butyl group R ² = 3,5-dibromo-4-hydroxybenzyl group / polymer (i)
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (36/34/30, weight average molecular weight 50,000)

[Alkali-soluble resin]
Resin 1: m-cresol / p-cresol (60/40) novolak (weight average molecular weight 4000)
Resin 2: phenol / m-cresol / p-cresol (50/30/20) novolak (weight average molecular weight 6000)

As shown in Table 1, the planographic printing plate precursors of the examples containing the specific structure polymer according to the present invention in the recording layer having a multi-layer structure have a wide development latitude, and image forming properties of a highlight area (small area image area) The image reproducibility of the image was also excellent.
On the other hand, the lithographic printing plate precursors of Comparative Examples 1 and 3 which are multi-layered recording layers but do not contain a specific structural polymer, the lithographic printing plates of the examples in both the development latitude and the image forming property of the highlight portion. It was inferior to the original version. The planographic printing plate precursor of Comparative Example 2 containing a specific structure polymer and an alkali-soluble resin having a phenolic hydroxyl group in a single recording layer was a planographic printing plate precursor having a narrow development latitude.

Claims (2)

On the support, a lower layer containing a polymer compound represented by the following general formula (I), an alkali-soluble resin having a phenolic hydroxyl group, and a dissolution inhibitor that is a quaternary ammonium salt (however, dyes and image colorants And a top layer containing an infrared absorber, and a positive lithographic printing plate precursor characterized by having a recording layer.

[In General Formula (I), R ¹ represents a hydrocarbon group, and R ² represents an aromatic group having a hydroxyl group as a substituent. m = 5-40 mol%, n = 10-60 mol%, o = 1-20 mol%, and p = 5-50 mol%. ]   The positive lithographic printing plate precursor according to claim 1, wherein the dissolution inhibitor that is a quaternary ammonium salt is a compound shown below.