JP4749771B2 - Planographic printing plate precursor - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor, and in particular, to a positive photosensitive lithographic printing plate precursor that can provide a lithographic printing plate that has excellent inking properties and that suppresses development debris generation in a developing bath. is there.

The lithographic printing plate precursor has a configuration in which a recording layer comprising an image forming composition is provided on a support. In such a lithographic printing plate precursor, an image forming composition dispersed or dissolved in a solvent is applied to the surface of a support subjected to appropriate surface treatment, undercoating, back coating, etc., and dried to form a recording layer. By doing so, it can be manufactured. On the support, not only the recording layer but also an intermediate layer, a protective layer and the like can be provided by coating and drying as necessary.
A lithographic printing plate precursor is obtained by a method of performing surface exposure using a contact or projection method through an image mask on the surface of a recording layer, or by direct exposure by scanning or modulation of actinic rays or radiation based on image information from a computer. The image forming composition on the support is imagewise changed in physical properties, and then the image forming composition in the non-image area is removed (developed), and the image area and / or the non-image area is made hydrophilic as necessary. The surface of the support surface layer and the hydrophobic non-image area composed of the image forming composition (oil-based ink receptivity) It is made into a lithographic printing plate that has.
The lithographic printing plate thus obtained is usually subjected to a printing process by supplying dampening water and ink. In the printing process, the hydrophilic non-image area is dampening water, and the oleophilic image area is The ink is received and an ink image is formed on the printing plate surface. A printed matter can be obtained by transferring the obtained ink image directly or indirectly to a desired recording medium.

As the image forming composition constituting the recording layer, a positive type image forming composition using a heat mode process is useful. In the positive recording layer, it is useful from the viewpoint of improving the working efficiency at the time of printing to impart sufficient lipophilicity to the surface of the recording layer constituting the image portion and to improve the ink deposition property at the time of printing. However, as the lipophilicity of the surface of the recording layer is improved, the hydrophobicity becomes stronger and the developer permeability decreases, so that the developability during image formation tends to decrease. Therefore, it is preferable to use a material having a balance between hydrophilicity and oleophilicity in order to impart developability and inking property, but a material capable of sufficiently satisfying both hydrophilicity and oleophilicity is obtained. The current situation has not yet been obtained.
As a method for ensuring the lipophilicity of the recording layer surface, for example, a method using a polymer having a linear, branched or cyclic alkyl group having 4 to 20 carbon atoms such as phenolic hydroxyl group and stearyl group has been proposed ( For example, see Patent Document 1.) However, when the above lipophilic polymer is used as the main component of the binder, since the amount added is large, the influence on other properties such as developability is increased, and it is difficult to use it. On the other hand, when such a lipophilic polymer is used in a small amount as an additive, there is a problem in that the effect of improving the ink deposition property as expected cannot be obtained.

In addition, use of a polymer having a fluorine-based functional group has been proposed to suppress the developer permeability on the surface (see, for example, Patent Document 2), but a compound having a functional group containing a large number of fluorine atoms is repellent. Since it has not only aqueous and alkali developability but also oil repellency, there is a concern that when it is added in a large amount, not only the developability is lowered, but also the ink inking property on the surface is affected. Furthermore, since such a highly hydrophobic polymer does not have sufficient solubility in an alkaline developer, when it is continuously subjected to plate making processing, it tends to precipitate in the developer and cause development residue. There are concerns about problems such as sticking to the plate and causing stains.
In order to prevent the deposition of residue in the developer, it is common to adopt a method of introducing an alkali-soluble group into the polymer compound. In this case, however, the polymer becomes hydrophilic and the ink inking property decreases. To do. Therefore, usually, the amount of lipophilic group and alkali-soluble introduced is adjusted to balance the ink depositing property and the suppression of residue precipitation in the developer, and it has been difficult to achieve both of these characteristics.
JP 2004-117882 A JP 2002-72474 A

  The object of the present invention is excellent in the ink-thickness of the image area, a good printed matter can be obtained, and the occurrence of deposits such as development residue and sludge in the developer is suppressed even when the plate making process is continuously performed. Another object of the present invention is to provide a positive photosensitive lithographic printing plate precursor.

As a result of intensive studies, the present inventors have found that the above-described object can be achieved by using a polymer compound having a plurality of specific partial structures having different functions in the recording layer, leading to the solution of the present invention. It was.
That is, the lithographic printing plate precursor according to the invention is characterized in that a recording layer containing a polymer compound having a structure represented by the following (1) to (3) and an infrared absorber is provided on a support.
(1) Structure represented by the following general formula (1)

(In General Formula (1), Rf is a substituent containing a fluoroalkyl group or a perfluoroalkyl group having 9 or more fluorine atoms, and n is an integer of 1 to 3).
(2) Alkali-decomposable group-containing structure represented by the following general formula (2)

(In the general formula (2), R ¹ represents an aryl group, an alkyl group, or an acyl group in which the pKa of R ¹ OH is 3 to 9)
(3) A monovalent side chain structure having 6 or more carbon atoms.

Although the mechanism of action of the present invention is not clear, it is presumed as follows.
In the present invention, as described above, the polymer compound contained in the recording layer of the lithographic printing plate precursor has an alkali-decomposable structure in the fluorine-containing partial structure represented by (1) and the alkali-decomposable group-containing structure represented by (2). It has a monovalent side chain structure that exhibits high lipophilicity by containing a large number of functional groups and carbon atoms defined in (3). Here, due to the function of the fluorine-containing functional group having the structure represented by the general formula (1) represented by (1), this polymer has a tendency to be unevenly distributed on the surface, and accordingly (3) The highly lipophilic partial structure, which is a component defined by the above, is also oriented on the surface. Thereby, it is considered that the lipophilicity of the surface of the recording layer is improved and the ink deposition property is improved.
Further, since the side chain partial structure (3) has a relatively low affinity with a coexisting alkali-soluble resin such as a novolak resin, it exhibits a higher surface orientation without being uniformly dispersed in the recording layer. For this reason, it is considered that the oleophilicity of the surface of the recording layer is increased and the ink inking property is further improved.

In general, a polymer compound having a highly lipophilic side chain structure or a functional group having fluorine has a relatively low alkali solubility and often precipitates as a residue in a developer. However, the copolymer used in the recording layer in the present invention usually has hydrophilicity due to the function of the structure containing the functional group (alkali decomposable group) hydrolyzed by the alkaline solution shown in (2). Although not shown, acid groups are formed by hydrolysis of the alkali-decomposable groups in excess alkali solution, and alkali solubility in the developer is gradually improved. It is thought that it was done.

  According to the present invention, an excellent ink-inking property in an image area is obtained, and a good printed matter can be obtained, and the occurrence of deposits such as development residue and sludge in the developer is suppressed even when the plate making process is continuously performed. A positive-type photosensitive lithographic printing plate precursor can be obtained.

Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor according to the invention comprises (1) a structure represented by the general formula (1), (2) an alkali-decomposable group-containing structure represented by the general formula (2), and (3) It contains a polymer compound containing a monovalent side chain structure having 6 or more carbon atoms and an infrared absorber.
Hereinafter, the partial structures (1), (2), and (3) included in the polymer compound that characterizes the present invention will be described in detail.

[(1) Structure represented by the general formula (1)]
The structure represented by (1) general formula (1) contained in the polymer compound according to the present invention is a functional group containing a plurality of fluorines in the structure, and is hereinafter referred to as (1) fluorine-containing structure as appropriate. . (1) The structure represented by the general formula (1) is preferably introduced into the polymer compound as the following monomer.

(In the above formula, Rf is a fluoroalkyl group or perfluoroalkyl group-containing substituent having 9 or more fluorine atoms, n represents 1 or 2, and R ¹ represents hydrogen or a methyl group.)
Specific examples of the monomer having such a fluorine-containing structure (— (CH ₂ ) _m C _n F _{2n + 1} ) include the following fluoroalkyl (meth) acrylates.
CH ₂ = CRCO ₂ (CH ₂ ) _m C _n F _{2n + 1}
(M represents 1 or 2, n represents an integer of 4 to 12. R represents an alkyl group having 1 to 4 carbon atoms)
CH ₂ = CRCO ₂ (CH ₂ ) _m (CF ₂ ) _n H
(M represents 1 or 2, n represents an integer of 4 to 12. R represents an alkyl group having 1 to 4 carbon atoms)
Here, by using a fluoroalkyl group or a perfluoroalkyl group of Rf having 9 or more fluorine atoms, a photosensitive layer having a fluorine atom concentration distribution in the film thickness direction is formed, and the surface fluorine The concentration is high, and the inside has an effect that the fluorine concentration becomes low. In particular, when such a monomer is used as a copolymerization component, (1) when a fluorine-containing structure is introduced into a polymer, the number of fluorine atoms per monomer unit is 13 or more to increase the surface fluorine concentration. More preferred above.

Further, the fluorine atom content per polymer is preferably 5 mmol / g or more for increasing the fluorine concentration on the surface, and more preferably 10 mmol / g or more. Although there is no restriction | limiting in particular in the upper limit of fluorine atom content contained in a high molecular compound, When other physical properties of the high molecular compound obtained are considered, it is preferable that it is 40 mmol / g or less, More preferably, it is 35 mmol / g or less. It is.
In synthesizing the polymer compound according to the present invention, considering the preferred fluorine atom content suitable for the desired physical properties and (1) the number of fluorine atoms contained in the fluorine-containing structure (functional group), What is necessary is just to determine the preparation amount of a fluorine-containing monomer suitably. Moreover, after synthesizing the polymer, (1) such a fluorine-containing structure can be introduced.

[(2) Alkali-decomposable group-containing structure represented by general formula (2)]
In the alkali-decomposable group-containing structure represented by the following general formula (2), R ¹ in the general formula (2) represents a hydrocarbon group in which the pKa of R ¹ OH is 3 to 9.

Examples of the hydrocarbon group represented by R ¹ include an alkyl group and an aryl group. Among these, a hydrocarbon group within the above pKa range is selected and used. Normally, by introducing an electron-withdrawing substituent into the hydrocarbon group represented by R ¹ , the pKa of R ¹ OH falls within the above range. Here, the method for measuring the pKa of R ¹ OH is not particularly limited, but as a method for experimentally examining, a usual titration method may be mentioned. In addition, it is possible to examine the pKa known from the literature such as the chemical handbook (Chemical Society of Japan <Maruzen Co., Ltd.>), and it is also possible to calculate from the compound structure by calculation software such as ACD / pKa DB. It is.
The preferred hydrocarbon group represented by R ¹ is a hydrocarbon having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 20 carbon atoms or an aryl having 6 to 20 carbon atoms. Groups.

Particularly preferred alkyl groups include methyl group, ethyl group, propyl group, butyl group, hexyl group, dodecyl group, isopropyl group, isobutyl group, cyclohexyl group, benzyl group, vinyl group, allyl group, hexenyl group and the like. Those containing an unsaturated hydrocarbon group are also preferably used.
Particularly preferred aryl groups include a phenyl group, a naphthyl group, and an anthranyl group. The aryl group in the present invention includes a heteroaromatic pyridinyl group, furanyl group, thiophenyl group, and the like.

These hydrocarbon groups may further have a substituent, and preferable substituents that can be introduced include alkoxy groups, aryloxy groups, acyloxy groups (ester groups), sulfonyloxy groups (sulfonic acid ester groups), and the like. Substituted oxy groups typified by: substituted thio groups typified by alkylthio groups, arylthio groups, acylthio groups, sulfonylthio groups (sulfonic acid thioester groups), etc .; alkylamino groups, arylamino groups, acylamino groups (amide groups), Substituted amino groups typified by sulfonylamino groups (sulfonic acid amide groups); halogen atoms, cyano groups, nitro groups, carboxyl groups, substituted carbonyl groups (R ⁴ —C (═O) —), substituted sulfonyl groups (R ^5- S (= O) _2- ) and the like. Here, R ⁴ and R ⁵ represent a hydrogen atom, a hydrocarbon group, a substituted oxy group, a substituted thio group, or a substituted amino group.

R ¹ in the general formula (2) it is, from the condition is satisfied in view of the pKa of R ¹ OH is 3 to 9, it is preferably substituted by electron-withdrawing substituents as described above. In consideration of this point, the hydrocarbon group of R ¹ is particularly a halogen atom, cyano group, nitro group, carboxyl group, substituted carbonyl group (R ⁴ -C (= O)-) and a substituted sulfonyl group (R ⁵ —S (═O) ₂ —) are preferably substituted with at least one or more substituents.
As particularly preferred R ¹ , specifically, for example, trifluoromethyl group, trichloromethyl group, dichloromethyl group, tribromomethyl group, perfluoroethyl group, perfluorobutyl group, cyanomethyl group, nitromethyl group, fluorophenyl Group, chlorophenyl group, promophenyl group, cyanophenyl group, nitrophenyl group, dichlorophenyl group, trichlorophenyl group, trifluoromethylphenyl group, acetylphenyl group, diacetylphenyl group, benzoylphenyl group, methoxycarbonylphenyl group, phenoxycarbonylphenyl Group, methanesulfonyl group, toluenesulfonylphenyl group, chlorophenylsulfonylphenyl group; and a phenyl group having two or more of the aforementioned electron-withdrawing substituents; aromatic complex such as pyridinyl group Group, and the like.
Since the alkali-decomposable group-containing partial structure represented by the general formula (2) has a hydrocarbon group R ^{1 in} which the pKa of R ¹ OH is 3 to 9, such a partial structure is contained in an alkaline developer. In the following, it is referred to as (2) an alkali-decomposable group-containing structure as appropriate.

Specific examples of the (2) alkali-decomposable group-containing structure used in the present invention are shown below, but the present invention is not limited thereto. Incidentally, the numerical values set forth in () show a pKa of R ¹ OH in R ¹ in the structure of each compound cited as a specific example.

In the above specific examples, for those in which R ¹ in the structure is difficult to specify, the structure of R ¹ OH and the pKa thereof are shown together with the structure of the specific example of (2) alkali-decomposable structure. .

(2) The content rate of the alkali hydrolyzable group in the alkali-decomposable group-containing structure is preferably 0.2 to 10.0 mmol / g in the polymer compound according to the present invention, and more preferably 0.8. 5-5.0 mmol / g. The content consideration, (2) introduction amount of alkali-decomposable group-containing structure, or the like as appropriate copolymerization ratio of the monomer having an alkali-decomposable group-containing structure may be determined.

[(3) Monovalent side chain structure having 6 or more carbon atoms]
The side chain partial structure defined in (3) is a partial structure that exhibits high lipophilicity by having 6 or more carbons in the structure, and is hereinafter appropriately referred to as (3) highly lipophilic structure.
The (3) highly lipophilic structure used in the present invention is not particularly limited as long as it is a monovalent side chain structure having 6 or more carbon atoms, and a typical example is a cyclic structure having 6 or more carbon atoms. Alternatively, a chain monovalent hydrocarbon group may be mentioned, and the chain hydrocarbon may have a linear structure or a branched structure. The cyclic hydrocarbon group may have a structure such as an alicyclic ring, an alicyclic ring having a bridge structure, or an aromatic ring.

Preferably, it is a hydrocarbon group having 6 to 20 carbon atoms, more preferably an alkyl group having 6 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms.
Particularly preferred alkyl groups include linear aliphatic groups such as hexyl group and dodecyl group, branched aliphatic groups such as 2-ethylhexyl group, cyclic aliphatic groups such as cyclohexyl group, tricyclodecanyl group, adamantyl group and the like. And a group containing an unsaturated hydrocarbon group such as a bridged aliphatic group, a benzyl group, and a hexenyl group.
Particularly preferred aryl groups include a phenyl group, a naphthyl group, and an anthranyl group. The aryl group in the present invention includes a heteroaromatic pyridinyl group, furanyl group, thiophenyl group, and the like.

These hydrocarbon groups may further have a substituent, and preferable substituents that can be introduced include alkoxy groups, aryloxy groups, acyloxy groups (ester groups), sulfonyloxy groups (sulfonic acid ester groups), and the like. Substituted oxy groups typified by: substituted thio groups typified by alkylthio groups, arylthio groups, acylthio groups, sulfonylthio groups (sulfonic acid thioester groups), etc .; alkylamino groups, arylamino groups, acylamino groups (amide groups), Substituted amino groups typified by sulfonylamino groups (sulfonic acid amide groups); halogen atoms, cyano groups, nitro groups, carboxyl groups, substituted carbonyl groups (R ⁴ —C (═O) —), substituted sulfonyl groups (R ^5- S (= O) _2- ) and the like. Here, R ⁴ and R ⁵ represent a hydrogen atom, a hydrocarbon group, a substituted oxy group, a substituted thio group, or a substituted amino group.

(3) Preferred specific examples of the highly lipophilic structure (highly lipophilic functional group) are shown below.
For example, methoxycarbonyl group, ethoxycarbonyl group, propyloxycarbonyl group, butyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, 2-chloroethoxycarbonyl group, cyclohexyloxycarbonyl group, 2-hydroxyethyloxycarbonyl group, diethylaminoethyloxy Carbonyl group, furfuryloxycarbonyl group, tetrahydrofuryloxycarbonyl group, phenoxycarbonyl group, hydroxyphenyloxycarbonyl group, naphthoxycarbonyl group, benzyloxycarbonyl group, methoxybenzyloxycarbonyl group, carbamoyl group, N-ethylcarbamoyl group, N-propylcarbamoyl group, N-butylcarbamoyl group, N-hexylcarbamoyl group, N-octylcarbamoyl group, N-thio Rohexylcarbamoyl group, N-hydroxyethylcarbamoyl group, N-benzylcarbamoyl group, N-phenylcarbamoyl group, N-nitrophenylcarbamoyl group, N-tolylcarbamoyl group, N-hydroxyphenylcarbamoyl group, N, N-dimethylcarbamoyl Group, an N, N-diethylcarbamoyl group, an N, N-dicyclohexylcarbamoyl group, and an alkoxycarbonyl group having a bridge-like bond such as the following [(3) -1 to (3) -38], N-substituted, N, The structure which may have a branched structure, such as N-2 substituted carbamoyl group, may be mentioned.

  Also, for example, acetyloxy group, chloroacetyloxy group, trifluoroacetyloxy group, propionyloxy group, 2-chloropropionyloxy group, butyryloxy group, valeryloxy group, 2-ethylhexanoyl group, heptanoyl group, cyclohexanecarbonyloxy group 1-adamantanecarbonyloxy group, benzoyloxy group, 4-ethylbenzoyloxy group, 4-chlorobenzoyloxy group, 4-butoxybenzoyloxy group, 3,5-dichlorobenzoyloxy group, 2-naphthoyloxy group, etc. Structure is mentioned.

For example, 2-hydroxyethylhexyl group, 2-methoxyethylhexyl group, cyclohexyl group, phenyl group, naphthyl group, anthracenyl group, 4-chlorophenyl group, 6-bromonaphthyl group, 5-methoxyphenyl group cyclohexyloxy group, 2-ethylhexyloxy group, a phenyl group, a naphthyloxy group, 4-fluorophenyl group, a 4-methoxyphenyl group, 2,5-dibromophenyl group, 6-bromo-naphthyl _{group, -CH 2 OCOCH 3, -CH 2} OCOCH Examples of the structure include ₂ CH ₃ , —CH ₂ OCOC ₁₀ H ₂₃ , —CH ₂ OCOPh, —CH ₂ OCOCH ₂ Ph, phthalamide, 2-pyrrolidone, oxindole, indole, and pyrazole.

  The content of the partial structure (3) is preferably 0.2 to 20.0 mmol / g, more preferably 0.5 to 10.0 mmol / g in the syntactic compound according to the present invention. .

[Other monomers]
In addition, as long as the high molecular compound which concerns on this invention has the 3 types of partial structure of said (1)-(3), other structural units can be included and the range which does not impair the effect of this invention In the above, other monomers not containing these partial structures may be included as a copolymerization component for various purposes such as improving coatability, developing property, and adjusting alkali solubility.
Examples of other monomers that can be used in combination here include known monomers such as acrylonitrile, maleic anhydride, maleic imide, and monomers having acid groups listed in the following (1) to (6).
(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )
In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrogen atom or a hydrocarbon group which may have a substituent. .
Among the compounds having an acid group selected from the above (1) to (6), those having (1) a phenol group, (2) a sulfonamide group, and (4) a carboxylic acid group are preferable from the viewpoint of effects, In particular, (4) a carboxylic acid group is most preferable from the viewpoint of sufficiently securing the inking property and developability.

(1) Examples of the monomer having a phenolic hydroxyl group include monomers having a hydroxyaryl group in the side chain.
Moreover, as a monomer which has a hydroxyaryl group in a side chain, what contains at least 1 type of monomer represented by following General formula (1) can be mentioned, for example.

In general formula (1), R ¹¹ represents a hydrogen atom or a methyl group. R ¹² represents a hydrogen atom, a halogen atom, a hydrocarbon group having 10 or less carbon atoms, an alkoxy group having 10 or less carbon atoms, or an aryloxy group having 10 or less carbon atoms. p represents an integer of 1 to 3.
(2) As a polymer having a sulfonamide group, for example, a polymer composed of a minimum structural 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.

  (3) Examples of the alkali-soluble structural unit having an active imide group include a minimum structural unit derived from a compound having an active imide group. Examples of the structural unit as described above include a structural unit having at least one active imide group represented by the following structural formula and one or more polymerizable unsaturated groups.

(4) Examples of the alkali-soluble structural unit having a carboxylic acid group include a minimum structural unit derived from a compound having at least one carboxylic acid group and polymerizable unsaturated group in the molecule. .
(5) Examples of the alkali-soluble structural unit having a sulfonic acid group include a minimum structural unit derived from a compound having one or more sulfonic acid groups and polymerizable unsaturated groups in the molecule. .
(6) Examples of the alkali-soluble structural unit having a phosphoric acid group include a minimum structural unit derived from a compound having at least one phosphoric acid group and a polymerizable unsaturated group in the molecule. .
The monomer having an acidic group selected from the above (1) to (6) constituting the copolymer used in the present invention is not particularly limited to one kind, and two or more monomers having the same acidic group are used. Alternatively, those obtained by introducing two or more monomers having different acidic groups as copolymerization components can be used.
The amount of the acid group introduced into the specific copolymer is not particularly limited as long as the polymer compound can be dissolved in an alkaline developer having a pH of 10 to 13 due to the presence of the acid group.

  Moreover, as a monomer containing the acidic group which comprises the specific copolymer used for this invention, the most preferable thing is a monomer represented with the following general formula (I).

R ¹ in the general formula (I) represents a hydrogen atom or a methyl group, and particularly preferably a methyl group. Linking groups in the general formula (I) represented by R ^2, R ² is constituted by containing a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and two or more atoms selected from the group consisting of sulfur atoms A linking group having 2 to 82 atoms, specifically, a divalent group such as alkylene, substituted alkylene, arylene, or substituted arylene, or a plurality of these are linked by an amide bond or an ester bond. Groups having different structures. For example, a preferred example of the linking group having a chain structure includes a structure in which alkylenes such as ethylene and propylene are linked via an ester bond.
The linking group represented by R ² is more preferably an (n + 1) -valent hydrocarbon group having an aliphatic cyclic structure having 3 to 30 carbon atoms. Specific examples include compounds having an aliphatic cyclic structure such as cyclopropane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, dicyclohexyl, tercyclohexyl and norbornane. In addition, examples in which (n + 1) hydrogen atoms on an arbitrary carbon atom constituting a compound having an aliphatic chain structure having 5 to 20 atoms are removed to obtain a (n + 1) -valent hydrocarbon group are also exemplified. be able to.

One or more arbitrary carbon atoms of the compounds constituting the aliphatic cyclic and chain structures may be replaced with a heteroatom selected from a nitrogen atom, an oxygen atom, or a sulfur atom.
Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups. Group, alkoxy group, aryloxy group, mercapto group, aryl group, alkenyl group, alkynyl group and the like.

R ³ in the case where A in the general formula (I) is NR ³ — represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ³ include an alkyl group, an aryl group, an alkenyl group, and an alkynyl group.
Specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, isopropyl group, isobutyl group, sec-butyl group, 1 carbon number such as tert-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-norbornyl group Up to 10 linear, branched or cyclic alkyl groups.

A in the general formula (I) is preferably an oxygen atom or —NH— because synthesis is easy.
N in the general formula (I) represents an integer of 1 to 5, and is preferably 1 from the viewpoint of the inking property.
In addition, since there are too many acid groups represented by the carboxyl group in the specific polymer compound used in the present invention to obtain desired inking properties, the acid value per molecule of the specific copolymer is From the viewpoint of fleshing property, 10.0 mmol / g or less is preferable, and 5.0 mmol / g or less is more preferable.

The weight average molecular weight of the polymer compound in the present invention is appropriately determined from the viewpoints of agglomeration properties and suppression of development residue precipitation. Usually, when the molecular weight increases, the inking property is excellent, but the development residue tends to precipitate. On the contrary, if it is low, the development residue is easily suppressed, but the inking property is low. The molecular weight is preferably 1,000 to 1,000,000, more preferably 2,000 to 500,000, and still more preferably 3,000 to 300,000.
When the molecular weight is less than 1000, the film property is lowered and the effect of improving the inking property is insufficient. On the other hand, when it exceeds 1,000,000, it becomes difficult to dissolve in the development residue, and it becomes difficult to dissolve in the coating solvent, and handling properties such as coating properties tend to be lowered, and it tends to be difficult to obtain a uniform coating film.
The polymer compound of the present invention may be linear, branched, or have a block or graft structure.

  Hereinafter, the structures of the polymer compounds [(P-1) to (P-28)] suitable for the present invention will be exemplified together with their weight average molecular weights (Mw), but the present invention is not limited thereto. .

  When the polymer compound according to the present invention is used for the recording layer in a lithographic printing plate precursor, the polymer compound used may be a single compound or a mixture of one or more other fluorine-based polymer compounds. It may be used as The fluorine polymer compound used in combination is used in the range of 1 to 70% by mass, preferably 1 to 60% by mass, and more preferably 1 to 50% by mass, based on the total weight of the polymer component of the present invention. As the fluorine-based polymer compound that can be used in combination, commercially available compounds can be used without limitation, and specifically, fluorine-based polymers known as fluorine-based surfactants often used in the industry are preferably used.

  The content of the specific polymer compound according to the present invention in the recording layer can be determined as appropriate, but is usually 0.0001 to 20% by mass, preferably based on the total weight of nonvolatile components in the recording layer. It is 0.001-15 mass%, More preferably, it is the range of 0.01-10 mass%.

[Synthesis of the polymer compound according to the present invention]
<General synthesis method>
Hereinafter, specific examples of synthesis of the polymer compound used in the present invention will be described in detail.
<Synthesis Example 1: Synthesis of P-18>
To 200 ml of 1-methoxy-2-propanol heated to 80 ° C. under a nitrogen atmosphere, M-1620 <manufactured by Daikin Industries Ltd.> (0.35 mol), 2-chloro-4-cyanophenyl methacrylate (0.35 mol), FA-513M <manufactured by Hitachi Chemical Co., Ltd.> (0.3 mol), Wako Pure Chemical Industries radical polymerization initiator V-601 (0.01 mol), 1-methoxy-2-propanol (200 ml) mixed solution for 2 hours After dropping, the mixture was further stirred at 80 ° C. for 3 hours, returned to room temperature, and poured into distilled water (3 L). The precipitated powder was filtered, washed with water, and then vacuum-dried to obtain the target product P-18 in a yield of 93%. The structure of the polymer was confirmed by NMR, IR, GPC, and surface tension.
The polymer compound according to the present invention can be synthesized as described above. In addition, all polymers shown in the specific examples can be synthesized in the same manner as described above.

[Infrared absorber]
For the recording layer of the lithographic printing plate precursor according to the invention, an infrared absorber (infrared absorbing dye or pigment) having an absorption maximum at a wavelength of 700 nm to 1200 nm is further used. The infrared absorber has a function of absorbing light energy irradiation rays such as an infrared laser used for recording and generating heat, and is useful from the viewpoint of improving recording sensitivity.

  As the dye, commercially available dyes and 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, oxonol dyes And dyes such as 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.

  Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. .

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

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Furthermore, the dyes represented by the following general formulas (a) to (e) are preferable because of their excellent photothermal conversion efficiency. Particularly, the cyanine dyes represented by the following general formula (a) are used in the polymerizable composition of the present invention. In this case, it is most preferable because it gives high polymerization activity 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 in, R ^a represents a hydrogen atom, an alkyl group, an aryl 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 charge neutralization is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a hexagonal salt, in view of the storage stability of the recording layer coating solution. Fluorophosphate ions and aryl sulfonate ions.

  Specific examples of the cyanine dye represented by formula (a) that can be suitably used in the present invention include those exemplified below, and paragraph numbers [0017] to [0019] of JP-A-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 are bonded to each other to form a ring structure. Also 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, oxy group Or a substituent selected from amino groups, 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 the 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 each a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thiol group, Represents a 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 the general formula (d), R ²⁹ to R ³² each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ³³ and R ³⁴ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represents an integer of 0 to 4. R ²⁹ and R ³⁰ , or R ³¹ and R ³² may be bonded to each other to form a ring, and R ²⁹ and / or R ³⁰ is R ³³ and R ³¹ and / or R ³² is R ³⁴ A ring may be bonded to each other, and when there are a plurality of R ³³ or R ³⁴ , R ³³ or R ³⁴ may be bonded to each other to form a ring. X ¹ and X ² are each independently a hydrogen atom, an alkyl group, or an aryl group, and at least one of X ¹ and X ² 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 are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a hydroxyl group, or a carbonyl group that may have a substituent. Group, thio group, sulfonyl group, sulfinyl group, oxy group, amino group, and onium salt structure. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein include IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements can be mentioned, among which copper, magnesium, iron, zinc, cobalt, aluminum, titanium, and vanadium are preferable.

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

  Examples of pigments used as infrared absorbers in the present invention include commercially available pigments and Color Index (CI) manual, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology”. (CMC Publishing, published in 1986) and “Printing Ink Technology”, published by CMC Publishing, published in 1984).

  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 other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

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

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

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  When these pigments or dyes are used in combination, from the viewpoint of balance between sensitivity, layer uniformity, and durability, 0.01 to 30% by mass, preferably 0.1 to 30% by mass with respect to the total solid content constituting the recording layer. In the case of 10% by mass, particularly in the case of a dye, 0.1 to 5% by mass, and particularly in the case of a pigment, 0.2 to 10% by mass can be added.

[Water-insoluble and alkali-soluble resin]
In the recording layer according to the present invention, it is preferable to use a water-insoluble and alkali-soluble resin (hereinafter, appropriately referred to as an alkali-soluble resin) from the viewpoint of improving the film property.
Examples of the alkali-soluble resin that can be used in the positive recording layer include homopolymers containing an acidic group in the main chain and / or side chain in the polymer, copolymers thereof, or mixtures thereof.
Among them, in the polymer compound according to the present invention, those having the acidic groups listed in (1) to (6) mentioned as other preferable copolymerization components in the main chain and / or side chain of the polymer, It is preferable in terms of solubility in an alkaline developer and expression of dissolution inhibiting ability.

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

Hereinafter, the alkali-soluble resin having an acidic group selected from the above (1) to (6) will be described.
(1) Examples of the alkali-soluble resin having a phenol group include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, m− / p. A novolak resin such as a condensation polymer of mixed cresol and formaldehyde, a condensation polymer of phenol and cresol (any of m-, p-, or m- / p-mixing) and formaldehyde, and pyrogallol and acetone Can be mentioned. Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned. 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.

  (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, an acid group used as the copolymerization component Preferred examples include compounds represented by the general formula (i) to the general formula (v) mentioned in the description of the monomer having.

  Among the compounds represented by the general formulas (i) to (v), in the positive planographic printing plate precursor of the present invention, in particular, m-aminosulfonylphenyl methacrylate and N- (p-aminosulfonylphenyl) methacryl are used. Amide, 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 constitutional unit having an acidic group selected from the above (1) to (6) constituting the alkali-soluble resin used for the positive recording layer is not particularly limited to one kind, and is the minimum having the same acidic group. Two or more kinds of structural units or two or more kinds of minimum structural units having different acidic groups may be copolymerized.

  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.

In this invention, when copolymerizing a compound and using an alkali-soluble resin as a copolymer, the other compound which does not contain the acidic group of said (1)-(6) can also be used as a compound to copolymerize. Examples of other compounds not containing an acidic group of (1) to (6) include the compounds listed in the following (m1) to (m12), but are not limited thereto.
(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

  The alkali-soluble resin preferably has a phenolic hydroxyl group from the viewpoint of excellent image-forming properties when exposed to infrared laser or the like. For example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- Preferred are novolak resins such as / p-mixed cresol formaldehyde resin and phenol / cresol (m-, p-, or m- / p-mixed) mixed formaldehyde resin and pyrogallol acetone resin.

  Further, as an alkali-soluble resin having a phenolic hydroxyl group, as described in US Pat. No. 4,123,279, a carbon number of 3 such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin is used. And a condensation polymer of phenol and formaldehyde having an alkyl group of ˜8 as a substituent.

  The alkali-soluble resin preferably has a weight average molecular weight of 500 or more from the viewpoint of image forming properties, and more preferably 1,000 to 700,000. The number average molecular weight is preferably 500 or more, and more preferably 750 to 650,000. The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

  These alkali-soluble resins may be used alone or in combination of two or more. In the case of combination, it has 3 to 8 carbon atoms such as a condensation polymer of t-butylphenol and formaldehyde or a condensation polymer of octylphenol and formaldehyde as described in US Pat. No. 4,123,279. A polycondensation product of phenol and formaldehyde having an alkyl group as a substituent, an alkali having a phenol structure having an electron-withdrawing group on an aromatic ring described in JP-A-2000-241972 previously filed by the present inventors A soluble resin or the like may be used in combination.

  The total content of the alkali-soluble resin in the present invention is preferably from 30 to 98% by mass, and preferably from 40 to 95% by mass in the total solid content of the recording layer, from the viewpoints of sensitivity of the recording layer, image formability and durability. % Is more preferable.

[Other additives]
(Dissolution inhibitor)
The positive recording layer according to the present invention is further thermally decomposable such as an onium salt, an o-quinonediazide compound, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, and the like, and is soluble in an alkali-soluble resin when not decomposed. Can be used in combination with a substance that substantially lowers. Addition of these compounds is preferable from the viewpoint of improving dissolution inhibition of the image area in the developer. In a positive recording layer, a substance that forms an interaction with an alkali-soluble resin and substantially reduces its solubility, such as a cyanine dye, is generally used as an infrared absorber. It is important to use these compounds in combination when not having a dissolution inhibitory action.

  Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, and arsonium salts. The onium salt is preferably added in an amount of 1 to 50% by mass, more preferably 5 to 30% by mass, especially 10 to 30% by mass, based on the total solid content constituting the image recording material. preferable.

Furthermore, for the purpose of improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in combination.
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, and particularly preferably 0.1 to 10%. % By mass.

  Besides these, epoxy compounds, vinyl ethers, further phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group described in JP-A-8-276558, and the present 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 recording layer in the present invention, a nonionic surfactant as described in JP-A-62-251740 and JP-A-3-208514 is used in order to broaden the processing stability against the development conditions. , Amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149 can be added.

In the recording layer of the present invention, a print-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
In addition, a plasticizer is added to the recording layer of the present invention as necessary in order to impart flexibility of the coating film. For example, butyl phthalyl, 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.

[Preparation of lithographic printing plate precursor]
A lithographic printing plate precursor is produced by dissolving the components for coating solution of a desired layer, such as the recording layer coating solution according to the present invention and the protective layer coating solution described later, in a solvent and coating the solution on a suitable support. be able to.
The recording layer may have a single layer structure or a multilayer structure.
When the recording layer of the lithographic printing plate precursor according to the present invention has a multilayer structure composed of a plurality of layers having different constituent components, for example, a lower layer containing an alkali-soluble resin, an alkali-soluble resin, and the alkali-soluble resin And an upper layer capable of forming an image by irradiation with infrared rays, and containing a specific infrared absorber in at least one of the upper layer and the lower layer Can be taken. In this case, the specific copolymer and infrared absorber in the present invention are contained in the upper layer. The lower layer may be a layer mainly composed of an alkali-soluble resin, or may further be a layer functioning as a positive recording layer containing an infrared absorber and a dissolution inhibitor.

The case where the recording layer according to the present invention has a multilayer structure will be described below.
-Lower layer component-
The lower layer according to the present invention is characterized by containing an alkali-soluble resin. As the alkali-soluble resin used here, the general alkali-soluble resin described above can be used, but in order to clarify the boundary between the upper layer and the lower layer, the alkali-soluble resin used in the lower layer is the alkali used in the upper layer. It is preferable that the main component is different from the soluble resin. Examples of the alkali-soluble resin suitably used for the lower layer include a copolymer of N- (p-aminosulfonylphenyl) (meth) acrylamide, (meth) acrylic acid alkyl ester and acrylonitrile, 4-maleimidobenzenesulfonamide and styrene. Copolymers, alkali-soluble resins having highly polar units such as copolymers of (meth) acrylic acid, N-phenylmaleimide, and (meth) acrylamide, or those resins in which the specific substituent is introduced However, the present invention is not limited to these.
The content of the total alkali-soluble resin in the lower layer of the multilayer recording layer is preferably 50 to 100% by mass in the total solid content of the lower recording layer from the viewpoint of printing durability and multilayer formation. 75 to 99% by mass, more preferably 85 to 95% by mass.
The lower layer may or may not contain the specific copolymer.

  In addition, other additives may be used for the lower layer component according to the present invention, if necessary. Examples of other additives include development accelerators, surfactants, printout / coloring agents, plasticizers, and WAX agents. Details of these components are the same as those described above.

-Upper layer component-
The upper layer according to the present invention contains an alkali-soluble resin and a compound that interacts with the alkali-soluble resin and decreases the solubility in an aqueous alkali solution (generally, an infrared-absorbing dye such as a cyanine dye having the function) An image can be formed by irradiation with infrared rays. The upper layer component is the same as that described above as the recording layer. In the present invention, the recording layer containing the specific copolymer and the infrared absorber is used as the upper layer.

Solvents used for coating the recording layer 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, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, water, etc. However, the present invention 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.

  Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

  In the recording layer coating solution according to the present invention, a surfactant for improving the coating property, for example, a fluorosurfactant described in JP-A-62-170950 may be added. it can. A preferable addition amount is 0.01 to 1% by mass in terms of solid content in the recording layer, and more preferably 0.05 to 0.5% by mass.

In the multilayer recording layer, it is preferable to form the lower layer and the upper layer by separating the two layers in principle.
As a method for forming the two layers separately, 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 after applying the upper layer, a solvent is rapidly used. For example, a method of drying and removing.
Hereinafter, although these methods are explained in full detail, the method of isolate | separating and apply | coating two layers is not limited to these.

  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 the lower layer component, a component insoluble in a solvent such as methyl ethyl ketone or 1-methoxy-2-propanol that dissolves the alkali-soluble resin that is the upper layer component is selected, and the lower layer is applied using a solvent system that dissolves the lower layer component. -It is possible to form two layers by drying and then dissolving the upper layer component mainly composed of alkali-soluble resin with methyl ethyl ketone, 1-methoxy-2-propanol, etc., and applying and drying.

  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.

  Moreover, in order to provide a new function, the upper layer and the lower layer may be partially miscible in a range where the effects of the present invention are sufficiently exhibited. Such a method can be achieved by adjusting the degree of any of the above methods using the difference in solvent solubility and the method of drying the solvent very quickly after coating the second layer.

Moreover, the recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, but as the coating amount decreases, the apparent sensitivity increases, but the film properties of the recording layer decrease. .
In the single-layer recording layer, the coating amount of the recording layer component after drying is generally preferably from 0.5 to 5.0 g / m ² from the viewpoint of sensitivity, printing durability, and the like, and preferably from 0.7 to 4 More preferably, it is in the range of 0.0 g / m ² , more preferably in the range of 0.8 to 3.0 g / m ² .
In the multi-layer recording layer, the coating amount of the lower layer component after drying is preferably in the range of 0.5 to 4.0 g / m ² , more preferably 0.6, from the viewpoint of sensitivity and printing durability. It is in the range of ˜2.5 g / m ² . The coating amount of the upper layer component after drying is preferably in the range of 0.05 to 1.0 g / m ² , and more preferably 0.08 to 0.08 from the viewpoint of sensitivity, development latitude, scratch resistance, and the like. The range is 0.7 g / m ² .
The coating amount after drying combining the lower layer and the upper layer is preferably in the range of 0.6 to 4.0 g / m ² , more preferably from the viewpoint of sensitivity, image reproducibility, printing durability, and the like. in the range of 0.7 to 2.5 g / m ^2.

[Support]
The support used in the lithographic printing plate precursor according to the present invention is not particularly limited as long as it is a dimensionally stable plate having the required strength and durability. 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 metal as described above, or vapor-deposited paper, or plastic film.

  Among them, in 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 different 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.

Such an aluminum plate may be subjected to surface treatment such as roughening treatment or anodizing treatment, if necessary. Hereinafter, such a surface treatment will be briefly described.
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 JP-A-54-63902, a method in which both are combined can also be used.
The aluminum plate roughened as described above is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodizing 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)
In the lithographic printing plate precursor according to the invention, an undercoat layer can be provided between the support and the recording layer, if necessary.
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 which may have a substituent, Organic phosphonic acids such as naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphonic acid, alkylphosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acids such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloride of triethanolamine Hydroxy groups such as Selected from hydrochloride of the amine to be, but may be used by mixing two or more.

  The undercoat layer preferably contains a compound having an onium group. The compounds having an onium group are described in detail in JP-A Nos. 2000-10292 and 2000-108538. In addition, a compound selected from the group of polymer compounds having a structural unit represented by poly (p-vinylbenzoic acid) in the molecule can also be used. Specific examples of these polymer compounds include a copolymer of p-vinylbenzoic acid and vinylbenzyltriethylammonium salt, a copolymer of p-vinylbenzoic acid and vinylbenzyltrimethylammonium chloride, and the like. .

This organic undercoat layer 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 with water or the like and dried to provide an organic 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 organic 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.
The lithographic printing plate precursor produced as described above is imagewise exposed and then developed.

(Back coat layer)
A back coat layer is provided on the back surface of the support of the lithographic printing plate precursor according to the invention, if necessary. Such a back coat layer comprises a metal oxide obtained by hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174. A coating layer is preferably used. Among these coating layers, silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , and Si (OC ₄ H ₉ ) ₄ are available at a low price. The coating layer of the metal oxide obtained therefrom is particularly preferable because of its excellent developer resistance.

〔exposure〕
The actinic ray light source used for image exposure of the lithographic printing plate precursor according to the invention is preferably a light source having an emission wavelength in the near infrared to infrared region, and a solid laser or a semiconductor laser is particularly preferred.

[Development processing]
The developer that can be applied to the development processing of 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 for the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples 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 developers exhibiting the effect of the present invention contains one containing an alkali silicate as a base, or an alkali silicate mixed with a silicon compound in a base, The so-called “silicate developer” is an aqueous solution having a pH of 12 or more, and another more preferable developer does not contain an alkali silicate and contains a non-reducing sugar (an organic compound having a buffering action) and a base. “Non-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 and 1 to 4% by weight. A manner containing potassium at least 20%, aqueous solution of an alkali metal silicate is preferably used.

  A so-called “non-silicate developer” that does not contain an alkali silicate and contains a non-reducing sugar and a base is also preferable for application to the development of the lithographic printing plate precursor according to the invention. When the development processing of the lithographic printing plate precursor is performed using this developer, the surface of the recording layer is not deteriorated and the thickness of the recording layer can be maintained in a better state.

  The main component of the developer is preferably composed of at least one compound selected from non-reducing sugars and at least one base, and the pH of the solution is in the range of 9.0 to 13.5. Such non-reducing sugars are saccharides that do not have a free aldehyde group or ketone group and do not exhibit reducing properties, and are trehalose-type oligosaccharides in which reducing groups are bonded to each other, and glycosides in which a reducing group of saccharides and non-saccharides are bonded. It is classified into sugar alcohols reduced by hydrogenating the body and saccharides, and any of them is preferably used. Trehalose type oligosaccharides include saccharose and trehalose. Examples of glycosides include alkyl glycosides, phenol glycosides, mustard oil glycosides, and the like. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, zulsiit and allozulcit. Furthermore, maltitol obtained by hydrogenation of a disaccharide and a reduced form (reduced water candy) obtained by hydrogenation of an oligosaccharide are preferably used. Among these, sugar alcohol and saccharose are particularly preferred non-reducing sugars, and D-sorbite, saccharose, and reduced syrup are particularly preferred because they have a buffering action in an appropriate pH region and are inexpensive.

  These non-reducing sugars can be used singly or in combination of two or more, and the proportion of the non-reducing sugar in the developer is preferably 0.1 to 30% by mass from the viewpoint of buffering effect and developability, Preferably, it is 1-20 mass%.

  A conventionally known alkaline agent can be used as the base to be combined with the non-reducing sugar. For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, sodium carbonate, potassium carbonate, Examples include inorganic alkali agents such as ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate. In addition, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used.

These alkali agents are used alone or in combination of two or more. Among these, sodium hydroxide and potassium hydroxide are preferable because the pH can be adjusted in a wide pH range by adjusting these amounts relative to the non-reducing sugar. Further, trisodium phosphate, tripotassium phosphate, sodium carbonate, potassium carbonate and the like are preferable because they have a buffering action.
These alkali agents are added so that the pH of the developer is in the range of 9.0 to 13.5, and the addition amount is determined by the desired pH, the type and addition amount of the non-reducing sugar, and more preferable pH. The range is 10.0 to 13.2.

Further, an alkaline buffer composed of a weak acid other than sugars and a strong base can be used in combination with the developer. As the weak acid used as such a buffer, one having a dissociation constant (pKa) of 10.0 to 13.2 is preferable.
Such a weak acid is selected from those described in IONATION CONSTANTS OF ORGANIC ACIDS IN AQUEOUS SOLUTION published by Pergamon Press, for example, 2,2,3,3-tetrafluoropropanol-1 (PKa 12.74) , Alcohols such as trifluoroethanol (12.37) and trichloroethanol (12.24), aldehydes such as pyridine-2-aldehyde (12.68) and pyridine-4-aldehyde (12.05) , Salicylic acid (13.0), 3-hydroxy-2-naphthoic acid (12.84), catechol (12.6), gallic acid (12.4), sulfosalicylic acid (11.7) 3,4-dihydroxysulfonic acid (12) 2), 3,4-dihydroxybenzoic acid (11.94), 1,2,4-trihydroxybenzene (11.82), hydroquinone (11.56), pyrogallol (11.34), o -Compounds having phenolic hydroxyl groups such as cresol (10.33), resorcinol (11.27), p-cresol (10.27), m-cresol (10.09), 2-butanone oxime ( 12.45), acetoxime (12.42), 1,2-cycloheptanedione dioxime (12.3), 2-hydroxybenzaldehyde oxime (12.10), dimethylglyoxime (11.9) ), Ethanediamide dioxime (11.37), oximes such as acetophenone oxime (11.35), adenosine (12.5 6) Nucleic acid-related substances such as inosine (12.5), guanine (12.3), cytosine (12.2), hypoxanthine (12.1), xanthine (11.9), etc. Diethylaminomethylphosphonic acid (12.32), 1-amino-3,3,3-trifluorobenzoic acid (12.29), isopropylidenediphosphonic acid (12.10), 1,1-ethylidene Diphosphonic acid (11.54), 1,1-ethylidene diphosphonic acid 1-hydroxy (11.52), benzimidazole (12.86), thiobenzamide (12.8), picoline thioamide (same as above) Weak acids such as 12.55) and barbituric acid (12.5).

  Of these weak acids, sulfosalicylic acid and salicylic acid are preferred. As the base to be combined with these weak acids, sodium hydroxide, ammonium, potassium and lithium are preferably used. These alkali agents are used alone or in combination of two or more. The above various alkali agents are used by adjusting the pH within a preferable range by the concentration and combination.

  Various surfactants and organic solvents can be added to the developer as necessary for the purpose of promoting developability, dispersing development residue, and improving the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants.

  Preferred examples of the surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan Fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, poly Glycerin fatty acid partial esters, polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acids Nonionic surfactants such as ethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, fatty acid salts, abietic acid salts, hydroxy Alkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene Alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated tallow oil Fatty acid alkyl ester sulfate ester salt, alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, fatty acid monoglyceride sulfate ester salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphorus Acid ester salts, polyoxyethylene alkyl ether phosphoric acid ester salts, polyoxyethylene alkyl phenyl ether phosphoric acid ester salts, partially saponified products of styrene / leic anhydride copolymer, partial saponification of olefin / maleic anhydride copolymer Products, anionic surfactants such as naphthalenesulfonate formalin condensates, alkylamine salts, quaternary ammonium salts such as tetrabutylammonium bromide, Examples thereof include cationic surfactants such as reoxyethylene alkylamine salts and polyethylene polyamine derivatives, and amphoteric surfactants such as carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines. Among the surfactants listed above, those having polyoxyethylene can be read as polyoxyalkylenes such as polyoxymethylene, polyoxypropylene and polyoxybutylene, and these surfactants are also included.

  A more preferred surfactant is a fluorosurfactant containing a perfluoroalkyl group in the molecule. Such fluorosurfactants include perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, anionic types such as perfluoroalkyl phosphates, amphoteric types such as perfluoroalkyl betaines, and perfluoroalkyltrimethylammonium salts. Cationic and perfluoroalkyl amine oxides, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl group and hydrophilic group-containing oligomers, perfluoroalkyl group and lipophilic group-containing oligomers, perfluoroalkyl groups, hydrophilic groups and lipophilic groups Nonionic types such as group-containing oligomers, perfluoroalkyl groups, and lipophilic group-containing urethanes can be mentioned. Said surfactant can be used individually or in combination of 2 or more types, and is added in 0.001-10 mass% in a developing solution, More preferably, it is added in 0.01-5 mass%.

  Various development stabilizers can be used in the developer. Preferred examples thereof include polyethylene glycol adducts of sugar alcohols described in JP-A-6-282079, tetraalkylammonium salts such as tetrabutylammonium hydroxide, phosphonium salts such as tetrabutylphosphonium bromide, and iodonium such as diphenyliodonium chloride. A salt is a preferred example. Furthermore, anionic surfactants or amphoteric surfactants described in JP-A-50-51324, water-soluble cationic polymers described in JP-A-55-95946, and JP-A-56-142528 are described. And water-soluble amphoteric polymer electrolytes that have been used.

  Furthermore, an organic boron compound to which an alkylene glycol is added as described in JP-A-59-84241, a polyoxyethylene / polyoxypropylene block polymerization type water-soluble surfactant as described in JP-A-60-111246, An alkylenediamine compound substituted with polyoxyethylene / polyoxypropylene disclosed in JP-A-60-129750, a polyethylene glycol having a weight average molecular weight of 300 or more described in JP-A-61-215554, and a cation described in JP-A-63-175858 And a fluorine-containing surfactant having a functional group, a water-soluble ethylene oxide addition compound obtained by adding 4 mol or more of ethylene oxide to an acid or alcohol disclosed in JP-A-2-39157, and a water-soluble polyalkylene compound.

If necessary, an organic solvent is further added to the developer. As such an organic solvent, those having a solubility in water of about 10% by mass or less are suitable, and are preferably selected from those having 5% by mass or less. For example, 1-phenylethanol, 2-phenylethanol, 3-phenyl-1-propanol, 4-phenyl-1-butanol, 4-phenyl-2-butanol, 2-phenyl-1-butanol, 2-phenoxyethanol, 2- Benzyloxyethanol, o-methoxybenzyl alcohol, m-methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol and 4-methylcyclohexanol, N-phenylethanol Examples include amines and N-phenyldiethanolamine.
Content of the organic solvent is 0.1-5 mass% with respect to the total mass of a use liquid. The amount used is closely related to the amount of surfactant used, and it is preferable to increase the amount of surfactant as the amount of organic solvent increases. This is because the amount of the surfactant is small, and when the amount of the organic solvent is large, the organic solvent is not completely dissolved, so that it is impossible to expect good developability.

A reducing agent can be further added to the developer. This prevents the printing plate from being stained. Preferable organic reducing agents include phenol compounds such as thiosalicylic acid, hydroquinone, metol, methoxyquinone, resorcin, and 2-methylresorcin, and amine compounds such as phenylenediamine and phenylhydrazine. More preferable inorganic reducing agents include sodium, potassium and ammonium salts of inorganic acids such as sulfurous acid, bisulfite, phosphorous acid, hydrogen phosphite, dihydrogen phosphite, thiosulfuric acid and dithionite. A salt etc. can be mentioned.
Among these reducing agents, sulfites are particularly excellent in the antifouling effect. These reducing agents are preferably contained in the range of 0.05 to 5% by mass with respect to the developer at the time of use.

  An organic carboxylic acid can also be added to the developer. Preferred organic carboxylic acids are aliphatic carboxylic acids and aromatic carboxylic acids having 6 to 20 carbon atoms. Specific examples of the aliphatic carboxylic acid include caproic acid, enanthylic acid, caprylic acid, lauric acid, myristic acid, palmitic acid and stearic acid, and particularly preferred are alkanoic acids having 8 to 12 carbon atoms. . Further, it may be an unsaturated fatty acid having a double bond in the carbon chain or a branched carbon chain. The aromatic carboxylic acid is a compound in which a carboxyl group is substituted on a benzene ring, naphthalene ring, anthracene ring or the like, and specifically includes o-chlorobenzoic acid, p-chlorobenzoic acid, o-hydroxybenzoic acid, p- Hydroxybenzoic acid, o-aminobenzoic acid, p-aminobenzoic acid, 2,4-dihydrobenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 3, There are 5-dihydroxybenzoic acid, gallic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-naphthoic acid, 2-naphthoic acid and the like. Naphthoic acid is particularly effective.

  The aliphatic and aromatic carboxylic acids are preferably used as sodium salts, potassium salts or ammonium salts in order to enhance water solubility. The content of the organic carboxylic acid in the developer used in the present invention is not particularly limited, but if it is less than 0.1% by mass, the effect is not sufficient, and if it is 10% by mass or more, the effect cannot be further improved. In addition, dissolution may be hindered when other additives are used in combination. Therefore, the preferable addition amount is 0.1 to 10% by mass, and more preferably 0.5 to 4% by mass with respect to the developing solution at the time of use.

  If necessary, the developer may further contain a preservative, a colorant, a thickener, an antifoaming agent, a hard water softening agent, and the like. Examples of water softeners include polyphosphoric acid and its sodium, potassium and ammonium salts, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, 1,2-diaminocyclohexanetetra Aminopolycarboxylic acids such as acetic acid and 1,3-diamino-2-propanoltetraacetic acid and their sodium, potassium and ammonium salts, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylene Phosphonic acid), triethylenetetramine hexa (methylenephosphonic acid), hydroxyethylethylenediaminetri (methylenephosphonic acid) and 1-hydro The lower edge 1,1-diphosphonic acid and their sodium salts, potassium salts and ammonium salts.

  The optimum value of such a hard water softener varies depending on its chelation and the hardness of the hard water used and the amount of hard water. %, More preferably in the range of 0.01 to 0.5 mass%. If the addition amount is less than this range, the intended purpose is not sufficiently achieved. If the addition amount is more than this range, adverse effects on the image area such as color loss will occur. The remaining component of the developer is water. It is advantageous in terms of transportation that the developer is a concentrated solution having a water content less than that in use and is diluted with water when in use. In this case, the degree of concentration is appropriate such that each component does not cause separation or precipitation.

The developer described in JP-A-6-282079 can also be used as the developer used in the present invention. This is because 5 mol or more of ethylene oxide is added to an alkali metal silicate having a molar ratio of SiO ₂ / M ₂ O (M represents an alkali metal) of 0.5 to 2.0 and a sugar alcohol having 4 or more hydroxyl groups. A developer containing a water-soluble ethylene oxide addition compound obtained in this manner. Sugar alcohols are polyhydric alcohols corresponding to those obtained by reducing aldehyde groups and ketone groups of sugars to form primary and secondary alcohol groups, respectively. Examples of sugar alcohol shells include D, L-trait, erythritol, D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, Examples thereof include L-talit, dulcit, and allozulcit, and di-, tri-, tetra-, penta-, and hexaglycerin condensed with a sugar alcohol. The water-soluble ethylene oxide addition compound can be obtained by adding 5 mol or more of ethylene oxide to 1 mol of the sugar alcohol. Further, propylene oxide may be block-copolymerized to the ethylene oxide addition compound as required within a range where solubility is acceptable. These ethylene oxide addition compounds may be used alone or in combination of two or more.
The addition amount of these water-soluble ethylene oxide addition compounds is suitably 0.001 to 5% by mass, more preferably 0.001 to 2% by mass, with respect to the developer (use solution).

  The developer may further contain the above-described various surfactants and organic solvents as needed for the purpose of promoting developability, dispersing development residue, and improving ink affinity of the printing plate image area.

  A lithographic printing plate precursor developed with a developer having such a composition is subjected to post-treatment with a washing water, a rinse solution containing a surfactant, a finisher mainly composed of gum arabic or starch derivatives, or a protective gum solution. The These treatments can be used in various combinations for the post-treatment of the lithographic printing plate precursor according to the invention.

  In recent years, automatic developing machines for PS plates have been widely used in the stencil 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 conveying the PS plate, each processing liquid tank and a spray device, and the exposed PS plate is pumped up while being transported horizontally. Each processing solution is sprayed from a spray nozzle to develop and post-process. In addition, recently, a PS plate is immersed and transported in a processing solution tank filled with a processing solution by a guide roll in the solution, and a small amount of washing water after development is supplied to the plate surface for washing. A method is also known in which the waste water is reused as dilution water for the developer stock solution.

  In such automatic processing, each processing solution can be processed while being replenished with each replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can also be applied.

  In the lithographic printing plate precursor according to the invention, image portions unnecessary for the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, film edge marks of the original film, etc.) ), Unnecessary image portions are 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 from the lithographic printing plate precursor of the present invention as described above can be subjected to a printing process after applying a desensitizing gum if desired, but lithographic printing with a higher printing durability. If you want to make a plate, you will be burned. In the case of burning a lithographic printing plate, before burning, an adjustment as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. It is preferable to treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method in which the printing plate is immersed and applied in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting liquid is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). Is done. 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 lithographic 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.
(Production of support)
Supports A, B, C, and D were prepared by using a JIS-A-1050 aluminum plate having a thickness of 0.3 mm in combination with the following processes.

(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 lower part 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) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass 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 by spraying was performed with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (including 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 performed in order, and the support was prepared so that the etching amount in the step (e) was 3.4 g / m ² .

<Support B>
Except for omitting the steps (g), (h) and (i) among the above steps, each step was performed in order to prepare a support.

<Support C>
A support was prepared by sequentially performing each step 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. The body was made.

  Supports A, B, C, and D obtained as described above were subsequently subjected to the following hydrophilization treatment and undercoating treatment.

(K) Alkali metal silicate treatment Alkali metal silicate is obtained by immersing the aluminum support obtained by the anodizing treatment in a treatment layer of No. 3 sodium silicate 1 mass% aqueous solution at a temperature of 30 ° C. for 10 seconds. 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. The coating amount after drying was 16 mg / m ² .

<Undercoat liquid composition>
・ The following polymer compound 0.3g
・ Methanol 100g
・ Water 1.0g

[Examples 1 to 10, Comparative Examples 1 to 4]
A coating solution for the first layer (lower layer) having the following composition was applied to the obtained support A with a wire bar, and then dried in a drying oven at 150 ° C. for 60 seconds to obtain a coating amount of 0.85 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was carried out at 145 ° C. for 70 seconds in a drying oven, and positive lithographic printing plate precursors of Examples 1 to 8 and Comparative Examples 1 and 2 were prepared with a total coating amount of 1.15 g / m ² .

<First layer (lower layer) coating solution>
-Copolymer 1 (synthesized by the following) 2.133 g
・ Cyanine dye A (the following structure) 0.098g
2-Mercapto-5-methylthio-1,3,4-thiadiazole
0.030g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.100 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
・ The counter anion of ethyl violet is changed to 6-hydroxynaphthalenesulfonic acid 0.100 g
・ 3-Methoxy-4-diazodiphenylamine hexafluorophosphate
0.030g
・ Fluorosurfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Γ-Butyrolactone 13.8g

<Synthesis of Copolymer 1>
After stirring, 31.0 g (0.36 mol) of methacrylic acid, 39.1 g (0.36 mol) of ethyl chloroformate and 200 ml of acetonitrile were placed in a 500 ml three-necked flask equipped with a condenser and a dropping funnel, and cooled in an ice-water bath. The mixture was stirred while. To this mixture, 36.4 g (0.36 mol) of triethylamine was dropped with a dropping funnel over about 1 hour. After completion of the dropwise addition, the ice-water bath was removed, and the mixture was stirred at room temperature for 30 minutes.

  To this reaction mixture, 51.7 g (0.30 mol) of p-aminobenzenesulfonamide was added, and the mixture was stirred for 1 hour while warming to 70 ° C. in an oil bath. After completion of the reaction, the mixture was added to 1 liter of water with stirring, and the resulting mixture was stirred for 30 minutes. The mixture was filtered to take out a precipitate, which was slurried with 500 ml of water, then the slurry was filtered, and the obtained solid was dried to dry a white solid of N- (p-aminosulfonylphenyl) methacrylamide. Was obtained (yield 46.9 g).

  Next, 4.61 g (0.0192 mol) of N- (p-aminosulfonylphenyl) methacrylamide and 2.58 g of ethyl methacrylate (0.0258 mol) were added to a 20 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel. ), 0.80 g (0.015 mol) of acrylonitrile and 20 g of N, N-dimethylacetamide were added, and the mixture was stirred while heating to 65 ° C. with a hot water bath. To this mixture, 0.15 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name: “V-65”, manufactured by Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator and maintained at 65 ° C. The mixture was stirred for 2 hours under a nitrogen stream. This reaction mixture was further mixed with 4.61 g of N- (p-aminosulfonylphenyl) methacrylamide, 2.58 g of methyl methacrylate, 0.80 g of acrylonitrile, 20 g of N, N-dimethylacetamide and 0.15 g of “V-65”. Was dropped by a dropping funnel over 2 hours. After completion of the dropwise addition, the resulting mixture was further stirred at 65 ° C. for 2 hours. After completion of the reaction, 40 g of methanol was added to the mixture, cooled, and the resulting mixture was poured into 2 liters of water while stirring the water. After stirring the mixture for 30 minutes, the precipitate was removed by filtration and dried. 15 g of a white solid was obtained. It was 54,000 when the weight average molecular weight (polystyrene standard) of this specific copolymer 1 was measured by the gel permeation chromatography.

<Second layer (upper layer) coating solution>
Copolymer of ethyl methacrylate and 2-methacryloyloxyethyl succinic acid (molar ratio 67:33, weight average molecular weight 92,000) 0.030 g
Novolak resin P1: phenol cresol-formaldehyde novolak (phenol: m-cresol: p-cresol = 30: 30: 40, weight average molecular weight: 5500) 0.300 g
・ Sulphonium salt (the following structure) 0.1g
・ Cyanine dye A (the above structure) 0.015 g
・ The counter anion of ethyl violet is changed to 6-hydroxynaphthalenesulfonic acid
0.012g
・ Fluorine-based surfactant 0.011g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g
-Specific polymer compound or comparative copolymer according to the present invention (compound described in Table 1) 0.055 g

  Moreover, the structure of the comparative example copolymer [(AP-1)-(AP-5)] used for each comparative example is shown below with the weight average molecular weight (Mw).

[Evaluation of lithographic printing plate precursor]
The evaluation of the lithographic printing plate precursor was conducted for each of the development latitude, sensitivity, and shrinkability. Details of the evaluation method are as follows.

1. Presence or absence of sludge After blasting a lithographic printing plate precursor 1 m ² , 100 cc developer for PS plate (DT-2) manufactured by Fuji Photo Film Co., Ltd., which is a developer substantially free of alkali metal silicate Then, it was evaluated whether sludge due to precipitates and aggregates derived from the specific copolymer according to the present invention was generated in the processing solution. The case where generation | occurrence | production was not able to be confirmed visually was evaluated as (circle), and the case where generation | occurrence | production of sludge by deposit and an aggregate was confirmed visually was evaluated as x. The results are shown in Table 1 below.
2. Attaching property The lithographic printing plate precursor is imagewise exposed using a TrendSetter 3244F manufactured by CREO at a setter exposure of 8.0 W and 150 rpm, and a developer DT-1 for PS plate manufactured by Fuji Photo Film Co., Ltd. is used as a standard. After developing using the conditions, it was applied to a printing machine, and the number of printed sheets required to obtain a printed matter having no problem with ink on the image area was evaluated. The smaller the number, the better the inking property. The results are listed in Table 1 below.

  As shown in Table 1, it can be seen that the lithographic printing plate precursors of Examples 1 to 10 achieve improvement in the inking property. In addition, generation of sludge due to precipitates in the developer was not observed. On the other hand, as the lithographic printing plate precursor of Comparative Example 2, a polymer containing a comparative polymer compound (AP-2) having an oleophilic functional group and a fluorine-containing substituent is excellent in the inking property, Over time, the occurrence of sludge due to precipitates in the developer was observed. On the other hand, in Comparative Examples 1, 3, and 4 using a comparative polymer compound containing either a fluorine-containing monomer or a lipophilic monomer and either an alkali-decomposable monomer or a hydrophilic monomer as a copolymerization component, It was inferior to the examples, and was a problematic level for practical use.

[Examples 11 to 20, Comparative Examples 5 to 8]
In Examples 11-20 and Comparative Examples 5-8, the sulfonium salt was removed from the coating solution for the second layer (upper layer) in Examples 1-10 and Comparative Examples 1-4, and the polymer compounds listed in Table 2 were used. Except for the above, a lithographic printing plate precursor was obtained in the same manner and evaluated in the same manner. The results are shown in Table 2.

  As shown in Table 2, it can be seen that the planographic printing plate precursors of Examples 11 to 20 achieve improved inking properties and suppress the generation of sludge. On the other hand, any of the lithographic printing plate precursors of Comparative Examples 5 to 8 which do not contain the specific copolymer according to the present invention was inferior to the examples in terms of either an aggregating property or a development residue suppressing effect. From this result, it can be seen that the effects of the present invention are exhibited regardless of the presence or absence of the sulfonium salt in the recording layer.

[Examples 21 to 28, Comparative Examples 9 to 12]
A coating solution for the first layer (lower layer) having the following composition was applied to the obtained support C with a wire bar, and then dried in a drying oven at 130 ° C. for 60 seconds to obtain a coating amount of 0.60 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 150 ° C. for 60 seconds in a drying oven, and positive lithographic printing plate precursors of Examples 21 to 28 and Comparative Examples 9 to 12 were prepared with a total coating amount of 1.25 g / m ² .

<First layer (lower layer) coating solution>
・ Copolymer 1 2.133 g
・ Cyanine dye A (the above structure) 0.098 g
2-Mercapto-5-methylthio-1,3,4-thiadiazole
0.030g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.100 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
-The counter anion of ethyl violet is changed to 6-hydroxynaphthalenesulfonic acid 0.100 g
・ 3-Methoxy-4-diazodiphenylamine hexafluorophosphate
0.030g
・ Fluorosurfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Dimethylsulfoxide 13.8g

<Second layer (upper layer) coating solution>
Copolymer of ethyl methacrylate and 2-methacryloyloxyethyl succinic acid (molar ratio 67:33, weight average molecular weight 92,000) 0.030 g
Novolak resin P1: phenol cresol-formaldehyde novolak (phenol: m-cresol: p-cresol = 30: 30: 40, weight average molecular weight: 5500) 0.300 g
・ Sulphonium salt (the above structure) 0.1g
・ Cyanine dye A (the above structure) 0.015 g
-Ethyl violet counter anion changed to 6-hydroxynaphthalenesulfonic acid 0.012 g
・ Fluorine-based surfactant 0.011g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g
-Specific polymer compound or comparative copolymer according to the present invention (compound described in Table 3) 0.055 g

<Evaluation of Examples 21 to 28 and Comparative Examples 9 to 12>
The obtained lithographic printing plate precursors of Examples 21 to 28 and Comparative Examples 9 to 12 were evaluated in the same manner as in Example 1.

  As shown in Table 3, it can be seen that the lithographic printing plate precursors of Examples 21 to 28 achieve an improvement in the inking property, and there is no generation of sludge due to precipitates in the developer. On the other hand, the lithographic printing plate precursors of Comparative Examples 9 to 12 that do not contain the specific polymer compound according to the present invention in the recording layer are inferior in either the depositing property or the sludge suppressing effect due to precipitates in the developer. It was confirmed that

[Examples 29 to 36, Comparative Examples 13 to 16]
In Examples 29 to 36 and Comparative Examples 13 to 16, the sulfonium salt was removed from the coating solutions for the second layer (upper layer) of Examples 21 to 28 and Comparative Examples 9 to 12, and the polymer compounds described in Table 4 below were used. Except for using, all were evaluated in the same manner. The results are shown in Table 4.

  As shown in Table 4, it can be seen that the lithographic printing plate precursors of Examples 29 to 36 achieve an improvement in the inking property and there is no generation of sludge due to precipitates in the developer. On the other hand, any of the lithographic printing plate precursors of Comparative Examples 13 to 16 in which the recording layer does not contain the specific copolymer according to the present invention is any of the thickening property or the sludge suppressing effect due to the deposits in the developer. Was confirmed to be inferior.

[Examples 37 to 44, Comparative Examples 17 to 20]
A coating solution for the first layer (lower layer) having the following composition was applied to the obtained support D with a wire bar, and then dried in a drying oven at 150 ° C. for 60 seconds to obtain a coating amount of 0.81 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed in a drying oven at 150 ° C. for 60 seconds to prepare positive lithographic printing plate precursors of Examples 37 to 44 and Comparative Examples 17 to 20 with a total coating amount of 0.99 g / m ² .

<First layer (lower layer) coating solution>
-Copolymer 1 2.133 g
・ Cyanine dye A (the above structure) 0.098 g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.110 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
-The counter anion of ethyl violet is changed to 6-hydroxynaphthalenesulfonic acid 0.100 g
・ 3-Methoxy-4-diazodiphenylamine hexafluorophosphate
0.030g
・ Fluorosurfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Γ-Butyrolactone 13.8g

<Second layer (upper layer) coating solution>
Copolymer of ethyl methacrylate and 2-methacryloyloxyethyl succinic acid (molar ratio 67:33, weight average molecular weight 92,000) 0.030 g
Novolak resin P5: phenol cresol-formaldehyde novolak (phenol: m-cresol: p-cresol = 40: 40: 20, weight average molecular weight: 8000) 0.300 g
・ Sulphonium salt (the above structure) 0.020 g
・ Cyanine dye A (the above structure) 0.015 g
・ Fluorine-based surfactant 0.011g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g
-Specific polymer compound or comparative copolymer according to the present invention (compound described in Table 5) 0.055 g

<Evaluation of Examples 37 to 44 and Comparative Examples 17 to 20>
The lithographic printing plate precursor obtained in Example 1 was used except that the developer (DP-4) of a developer containing alkali metal silicate (produced by Fuji Photo Film Co., Ltd.) was used as the developer. The method was evaluated.

  As shown in Table 5, it can be seen that the planographic printing plate precursors of Examples 37 to 44 have improved inking properties, and there is no generation of sludge due to precipitates in the developer. On the other hand, any of the lithographic printing plate precursors of Comparative Examples 17 to 20 which do not contain the specific copolymer according to the present invention in the recording layer is any of the wall-thickness or the sludge suppressing effect caused by the deposits in the developer. Was confirmed to be inferior.

[Examples 45-52, Comparative Examples 21-24]
In Examples 45 to 52 and Comparative Examples 21 to 24, the sulfonium salt was removed from the coating liquid for the second layer (upper layer) of Examples 37 to 44 and Comparative Examples 17 to 20, and the polymer compounds described in Table 6 below were used. Except for using, all were evaluated in the same manner. The results are shown in Table 6.

  As shown in Table 6, it can be seen that the lithographic printing plate precursors of Examples 45 to 52 achieved improvement in the wall thickness and no generation of sludge due to precipitates in the developer. On the other hand, any of the lithographic printing plate precursors of Comparative Examples 20 to 24 that do not contain the specific copolymer according to the present invention is inferior in either the agglomeration property or the sludge suppressing effect due to precipitates in the developer. It was confirmed that

[Examples 53 to 60, Comparative Examples 25 to 28]
The following image-forming layer coating solution was applied to the obtained support D and dried at 150 ° C. for 1 minute to form an image-forming layer. The planographic printing of Examples 53 to 60 and Comparative Examples 25 to 28 I got the original version. The coating amount after drying was 1.55 g / m ² .

<Image forming layer coating solution>
Novolak resin P7: phenol cresol-formaldehyde novolak (phenol: m-cresol: p-cresol = 20: 60: 20, weight average molecular weight: 10200) 1.0 g
・ Cyanine dye A (the above structure) 0.05 g
0.01 g of a dye having 1-naphthalenesulfonic acid anion as the counter anion of Victoria Pure Blue BOH
・ Fluorosurfactant 0.05g
(Megafuck F-177, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 9.0g
・ 9.0 g of 1-methoxy-2-propanol
-Specific polymer compound or comparative copolymer according to the present invention (compound described in Table 7) 0.10 g

<Evaluation of Examples 53 to 60 and Comparative Examples 25 to 28>
The lithographic printing plate precursor obtained in Example 1 was used except that the developer (DP-4) of a developer containing alkali metal silicate (produced by Fuji Photo Film Co., Ltd.) was used as the developer. The method was evaluated.

As shown in Table 7, the lithographic printing plate precursors of Examples 53 to 60 achieved improvement in wall thickness and no generation of sludge due to precipitates in the developer.
From this, it can be seen that the lithographic printing plate precursor according to the present invention exhibits the excellent effects of the present invention not only in the case of having a multilayer structure but also having a single-layer recording layer. On the other hand, any of the lithographic printing plate precursors of Comparative Examples 25 to 28 that do not contain the specific copolymer according to the present invention is inferior in either the aggregating property or the sludge suppressing effect due to the precipitate in the developer. It was confirmed that

Claims (1)

A lithographic printing plate precursor comprising a recording layer containing a polymer compound having a structure represented by the following (1) to (3) and an infrared absorber on a support.
(1) Structure represented by the following general formula (1)

(In General Formula (1), Rf is a substituent containing a fluoroalkyl group or a perfluoroalkyl group having 9 or more fluorine atoms, and n is an integer of 1 to 3).
(2) Alkali-decomposable group-containing structure represented by the following general formula (2)

(In the general formula (2), R ¹ represents an aryl group, an alkyl group, or an acyl group in which the pKa of R ¹ OH is 3 to 9)
(3) Monovalent side chain structure having 6 or more carbon atoms