JP2007101714A - Negative lithographic printing precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative photosensitive recording material in which omission of a photosensitive layer is prevented. <P>SOLUTION: In a negative lithographic printing precursor having a photosensitive layer containing a polymerization initiator, a polymerizable compound and a binder polymer, and a protective layer in this order on a support, the photosensitive layer contains at least two specific binder polymers. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a negative lithographic printing plate precursor that can be directly drawn with a laser beam.

  Conventionally, as a lithographic printing plate precursor, a PS plate having a configuration in which a lipophilic photosensitive resin layer is provided on a hydrophilic support is widely used. As the plate making method, mask exposure (typically through a lithographic film) After the surface exposure), the desired printing plate was obtained by dissolving and removing the non-image area. In recent years, digitization techniques that electronically process, store, and output image information using a computer have become widespread. Various new image output methods corresponding to such digitization techniques have come into practical use. As a result, computer-to-plate (CTP) technology that scans highly directional light such as laser light according to digitized image information and directly produces a printing plate without going through a lithographic film is desired. Obtaining a lithographic printing plate precursor adapted to this is an important technical issue.

As a negative lithographic printing plate precursor capable of such scanning exposure, a photopolymerization initiator, an addition-polymerizable ethylenically unsaturated compound, and a repeating unit having a specific structure soluble in an alkali developer on a hydrophilic support. There has been proposed a photopolymerization type photosensitive layer containing a binder polymer having an oxygen content, and an oxygen-blocking protective layer as required (see, for example, Patent Document 1).
Further, for the purpose of improving productivity in the plate-making process, a negative lithographic printing plate precursor provided with a photopolymerizable photosensitive layer and an oxygen-blocking protective layer added with an inorganic layered compound on a hydrophilic support. Has also been proposed (see, for example, Patent Document 2).
JP 2004-318053 A Japanese Patent Laid-Open No. 11-038633

  However, when the present inventors made a careful and detailed observation of the negative lithographic printing plate precursor described in Patent Document 1, when an oxygen-blocking protective layer is provided, in the manufacturing process or during storage, sometimes It has been found that a phenomenon occurs in which the photosensitive layer is removed (hereinafter, this phenomenon is sometimes referred to as “photosensitive layer loss”). It was found that this phenomenon cannot be suppressed when combined with the protective layer to which the inorganic layered compound described in Patent Document 2 is added, but rather tends to deteriorate.

  An object of the present invention is to provide a negative lithographic printing plate precursor capable of being written by a laser, which prevents the above-mentioned problem of missing of the photosensitive layer. Another object of the present invention is to provide a negative lithographic printing plate precursor having high sensitivity to an infrared laser, excellent in image forming ability and printing durability, and capable of drawing at high speed.

  As a result of intensive studies to achieve the above problems, it has been found that the above object can be achieved by using at least two kinds of specific binder polymers in the photosensitive layer, and the present invention has been accomplished.

That is, the present invention provides a negative lithographic printing plate precursor having a photosensitive layer containing a polymerization initiator, a polymerizable compound and a binder polymer and a protective layer in this order on a substrate, wherein the photosensitive layer comprises at least the following general formula ( A negative lithographic printing plate precursor comprising a first binder polymer having a repeating unit represented by I) and an acrylic second binder polymer having at least (meth) acrylic acid as a repeating unit. .
Here, the protective layer preferably contains an inorganic layered compound.
Moreover, it is preferable that the said photosensitive layer contains an infrared absorber from the viewpoint of the high sensitivity with an infrared laser, or the drawing aptitude.
In addition, from the viewpoint of increasing sensitivity, it is preferable that the first binder polymer and / or the second binder polymer have a repeating unit having a radical polymerizable group in the side chain. Here, the radically polymerizable group of the first binder polymer is more preferably at least one selected from the group consisting of a (meth) acryl group, an allyl group, and a styryl group. The radically polymerizable group of the second binder polymer is more preferably at least one selected from the group consisting of a (meth) acryl group, an allyl group, and a styryl group.

  Here, “having in this order” means that a photosensitive layer and a protective layer are provided in this order on a support, and an intermediate layer, a backcoat layer, etc. are provided according to the purpose, and any other than these It does not deny the existence of layers.

The effect | action of this invention is estimated as follows.
As described above, when the first binder polymer is used alone, the discrimination between the image area and the non-image area during the development process is large and the image forming ability is good and the printing durability is good. The present inventors have found through the careful and detailed observation that missing occurs. The reason is not clear, but it is presumed that it is probably due to the long chain structure of the side chain of the first binder polymer, which is considered to have high mobility. Therefore, when an attempt was made to use a binder polymer, which is considered to have lower mobility than the first binder polymer, in the photosensitive layer, an acrylic second binder polymer having at least (meth) acrylic acid as a repeating unit was used as the photosensitive layer. In combination, the present inventors have found that it is possible to provide a negative lithographic printing plate precursor having good image forming ability (sensitivity) and printing durability while suppressing omission of the photosensitive layer.
In order not only to suppress the removal of the photosensitive layer, but also to have high sensitivity to an infrared laser and to simultaneously provide performance as a lithographic printing plate such as image forming ability (sensitivity) and printing durability, The composition, particularly the addition of an infrared absorber, the introduction of a copolymer having a radically polymerizable group in the side chain into the first and / or second binder polymer, the blending balance between the binder polymer and the polymerizable compound are also important. I found out that it works as a factor. Furthermore, by adding an inorganic stratiform compound to the protective layer, the above-described basic performances of suppressing the removal of the photosensitive layer, being highly sensitive to laser, and having excellent image forming ability (sensitivity) and printing durability are provided. From the above, the present inventors have found that it is possible to provide added value for the purpose of improving productivity in the plate making process without using slip paper.

According to the present invention, there is provided a high-sensitivity negative lithographic printing plate precursor capable of direct drawing by a laser and having excellent image forming ability (sensitivity) and printing durability, which suppresses removal of a photosensitive layer. be able to.
And even if it contains an inorganic stratiform compound such as a mica compound in the protective layer, it is possible to suppress the removal of the photosensitive layer, and at the same time, the original plates can be laminated together without requiring a slip sheet. Can do. As a result, handling and storage stability during storage can be improved, and productivity during plate making can also be improved.
Further, by introducing a repeating unit having a radical polymerizable group in the side chain into the first binder polymer and / or the second binder polymer, the photosensitive property is maintained while maintaining the image forming ability (sensitivity) and printing durability. Omission of layers can be suppressed.

  Hereinafter, the negative planographic printing plate precursor of the present invention will be described in detail.

The negative lithographic printing plate precursor of the present invention comprises, on a substrate, a polymerization initiator, a polymerizable compound, at least a first binder polymer having a repeating unit represented by the following general formula (I), and at least (meth) acrylic acid. It has a photosensitive layer containing an acrylic second binder polymer as a repeating unit and a protective layer in this order.

<Photosensitive layer>
First, the photosensitive layer will be described in detail.
(First binder polymer)
The first binder polymer contained in the photosensitive layer has a repeating unit represented by the following general formula (I).

（一般式（Ｉ）中、Ｒ¹は水素原子又はメチル基を表し、Ｒ²は炭素原子、水素原子、酸素原子、窒素原子及び硫黄原子からなる群より選択される２種以上の原子から構成され、その原子数が２〜８２である連結基を表す。Ａは酸素原子又は−ＮＲ³−を表し、Ｒ³は水素原子又は炭素数１〜１０の一価の炭化水素基を表す。ｎは１〜５の整数を表す。）

(In general formula (I), R ¹ represents a hydrogen atom or a methyl group, and R ² is composed of two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom. And represents a linking group having 2 to 82 atoms, A represents an oxygen atom or —NR ³ —, and R ³ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Represents an integer of 1 to 5.)

R ¹ in the general formula (I) represents a hydrogen atom or a methyl group, and a methyl group is particularly preferable.
The linking group represented by R ² in the general formula (I) is composed of two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom, and the total number of atoms. Is from 2 to 82, preferably from 2 to 50, and more preferably from 2 to 30. The linking group represented by R ² may have a substituent. The total number of atoms shown here refers to the number of atoms including the substituent when the linking group has a substituent.

More specifically, examples of the linking group represented by R ² in the general formula (I) include alkylene, substituted alkylene, arylene, substituted arylene, and the like, and these divalent groups include a plurality of amide bonds or ester bonds. Those having a linked structure are preferred.
Examples of the linking group having a chain structure include ethylene and propylene. A structure in which these alkylenes are linked via an ester bond is particularly preferable.

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 -10 linear, branched, or cyclic alkyl groups.
Specific examples of the aryl group include a phenyl group, a naphthyl group, and an indenyl group. A heteroaryl group having up to 10 carbon atoms containing at least one heteroatom selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom can also be used. Specifically, for example, a furyl group or a thienyl group Pyrrolyl group, pyridyl group, quinolyl group and the like.
Specific examples of the alkenyl group include straight chain groups having 2 to 10 carbon atoms such as vinyl group, 1-propenyl group, 1-butenyl group, 1-methyl-1-propenyl group, 1-cyclopentenyl group, 1-cyclohexenyl group and the like. Examples include a chain, branched, or cyclic alkenyl group.
Specific examples of the alkynyl group include alkynyl groups having 2 to 10 carbon atoms such as ethynyl group, 1-propynyl group, 1-butynyl group, and 1-octynyl group.
Here, the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ³ may further have a substituent, and examples of the substituent that can be introduced include a substituent that R ² can introduce. It is the same. However, the carbon number of R < ³ > is 1-10 including the carbon number of a substituent.

  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 in terms of printing durability.

  Although the preferable specific example of the repeating unit represented by general formula (I) is shown below, it is not specifically limited to these.

  Only one type of repeating unit represented by the general formula (I) may be contained in the first binder polymer, or two or more types may be contained. The first binder polymer may be a polymer composed of only the repeating unit represented by the general formula (I), but is usually combined with other repeating units and used as a copolymer. The total content of the repeating unit represented by the general formula (I) in the copolymer is appropriately determined depending on the structure, the design of the photosensitive layer, and the like, but preferably 1 to 1 with respect to the total molar amount of the first binder polymer component. It is contained in a range of 99 mol%, more preferably 5 to 40 mol%, still more preferably 5 to 20 mol%.

As other repeating units when used as a copolymer, conventionally known ones can be used without limitation as long as they are radically polymerizable monomers. Specific examples include monomers described in “Polymer Data Handbook—Basic Edition” (Edition of Polymer Society, Bafukan, 1986). One type of repeating unit may be used, or two or more types may be used in combination.
Moreover, as a preferable repeating unit, the unit which has a radically polymerizable group in a side chain, and the unit which has an amide group in a side chain are mentioned. Hereinafter, a unit having a radical polymerizable group in the side chain and a unit having an amide group in the side chain, which are preferable as a repeating unit with the repeating unit represented by the general formula (I), will be described.

  The radically polymerizable group in the preferred repeating unit as a copolymerization component with the repeating unit represented by the general formula (I) is not particularly limited as long as it is a group that can be polymerized by a radical, but the following general formula (A It is preferable that it is a radically polymerizable group of the structure represented by (C)-(C).

In general formulas (A) to (C), R ^{4 to} R ¹⁴ each independently represents a hydrogen atom or a monovalent substituent. X and Y each independently represent an oxygen atom, a sulfur atom, or —N—R ¹⁵ , and Z represents an oxygen atom, a sulfur atom, —N—R ^15, or a phenylene group. Here, R ¹⁵ represents a hydrogen atom or a monovalent organic group.

In the general formula (A), R ^{4 to} R ⁶ each independently represent a hydrogen atom or a monovalent substituent, and R ⁴ is a hydrogen atom or an alkyl group which may have a substituent. Organic groups such as hydrogen atom, methyl group, methylalkoxy group, and methyl ester group are particularly preferable. R ⁵ and R ⁶ may each independently have a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or a substituent. Alkyl group, aryl group which may have a substituent, alkoxy group which may have a substituent, aryloxy group which may have a substituent, alkylamino group which may have a substituent, substituted An arylamino group that may have a group, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, and the like, among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable.
Here, examples of the substituent that can be introduced into these groups include a methoxycarbonyl group, an ethoxycarbonyl group, an isopropyloxycarbonyl group, a methyl group, an ethyl group, and a phenyl group.
X represents an oxygen atom, a sulfur atom, or —N—R ¹⁵ , where R ¹⁵ includes an alkyl group which may have a substituent.

In the general formula (B), R ^{7 to} R ¹¹ each independently represent a hydrogen atom or a monovalent substituent. Specific examples include a hydrogen atom, a halogen atom, an amino group, and a dialkylamino group. A carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, Aryloxy group which may have a substituent, alkylamino group which may have a substituent, arylamino group which may have a substituent, alkylsulfonyl group which may have a substituent, substituent An arylsulfonyl group which may have a hydrogen atom, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent, and an aryl group which may have a substituent are preferable. Arbitrariness.
Here, as a substituent which can be introduced into these groups, those exemplified as the substituent which can be introduced in the general formula (A) are exemplified.
Y represents an oxygen atom, a sulfur atom, or —N—R ¹⁵ . Examples of R ¹⁵ include the same as those in general formula (A).

In the general formula (C), R ^{12 to} R ¹⁴ each independently represents a hydrogen atom or a monovalent substituent. Specific examples thereof include a hydrogen atom, a halogen atom, an amino group, and a dialkylamino group. A carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, Aryloxy group which may have a substituent, alkylamino group which may have a substituent, arylamino group which may have a substituent, alkylsulfonyl group which may have a substituent, substituent An arylsulfonyl group which may have a hydrogen atom, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent, and an aryl group which may have a substituent are preferable. Good.
Here, as a substituent which can be introduced into these groups, those exemplified as the substituent which can be introduced in the general formula (A) are exemplified.
Z represents an oxygen atom, a sulfur atom, —N—R ¹⁵ or a phenylene group. Examples of R ¹⁵ include the same as those in general formula (A).

Among these radical polymerizable groups, α-substituted methylacryl group [—OC (═O) —C (—CH ₂ Z) ═CH ₂ , Z = hydrocarbon group starting from a hetero atom], (meth) acryl group , An ethylenically unsaturated bond group such as an allyl group or a styryl group is preferred, and a (meth) acryl group, an allyl group or a styryl group is particularly preferred.
Specific preferred examples of the repeating unit having a structure represented by the general formulas (A) to (C) having a radical polymerizable group in the side chain are shown below, but are not limited thereto.

  Next, the amide group in a repeating unit preferable as a copolymerization component with the repeating unit represented by general formula (I) is described. Such an amide group is preferably an amide group having a structure represented by the following general formula (F).

In general formula (F), R ¹⁸ and R ¹⁹ are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, or It represents a substituted sulfonyl group, and R ¹⁸ and R ¹⁹ may be bonded to each other to form a ring structure.

Preferable examples of R ¹⁸ and R ¹⁹ will be described in detail. Examples of the alkyl group represented by R ¹⁸ and R ¹⁹ include linear, branched, and cyclic alkyl groups having 1 to 20 carbon atoms. Specific examples thereof include a methyl group, ethyl group, and ethyl group. Group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group, Examples thereof include s-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group and 2-norbornyl group. . Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

Examples of the substituent of the substituted alkyl group represented by R ¹⁸ and R ¹⁹ include a group composed of a monovalent nonmetallic atomic group excluding a hydrogen atom. Preferred examples include halogen atoms (—F, —Br, -Cl, -I), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkyl Carbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamo Ruoxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkyl Ureido group, N′-arylureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N-arylureido group, N′-alkyl-N -Alkylureido group, N'-alkyl-N-arylureido group, N ', N'-dialkyl-N-alkylureido group, N', N'-dialkyl-N-arylureido group, N'-aryl-N -Alkylureido group, N'-aryl-N-arylureido group, N ', N'-diaryl-N-alkylureido group, N', N'-diaryl- N-arylureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N -Alkyl-N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group (R ⁰¹ CO—), carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamo Group, alkylsulfinyl group, arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, (referred to as a sulfonato group) sulfo group (-SO ₃ H) and its conjugated base group, alkoxy sulfonyl group, aryloxy sulfonyl group, sulfinamoyl group N-alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, Sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group Phosphono group (—PO ₃ H ₂ ) and its conjugate base group (phospho A dialkylphosphono group (—PO ₃ (alkyl) ₂ ; alkyl = alkyl group, hereinafter the same), a diarylphosphono group (—PO ₃ (aryl) ₂ ; aryl = aryl group, the same hereinafter), An alkylarylphosphono group (—PO ₃ (alkyl) (aryl)), a monoalkylphosphono group (—PO ₃ (alkyl)) and its conjugate base group (referred to as an alkylphosphonato group), a monoarylphosphono group ( -PO ₃ referred to as H (aryl)) and its conjugated base group (aryl phosphite Hona preparative group), referred to as phosphonooxy group (-OPO ₃ H ₂₎ and its conjugated base group (phosphonatooxy group), dialkylphosphono group (- _{OPO 3 H (alkyl) 2)} , diaryl phosphono group _{(-OPO 3 (aryl) 2)} , alkylaryl phosphonooxymethyl (-OPO ₃ (alkyl) (aryl)), (referred to as alkylphosphonato group) monoalkyl phosphono group (-OPO ₃ H (alkyl)) and its conjugated base group, monoarylphosphono group (- OPO ₃ H (aryl)) and its conjugate base group (referred to as arylphosphonatoxy group), cyano group, nitro group, aryl group, alkenyl group, alkynyl group, heterocyclic group, silyl group and the like.

  Specific examples of the alkyl group in these substituents include the above-described alkyl groups, and specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, a tolyl group, a xylyl group, a mesityl group, and a cumenyl group. , Chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylamino Phenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxyphenylcarbonyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, cyanophene Group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl group, and a phosphate Hona preparative phenyl group.

Examples of the alkenyl group in these substituents include vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group, and the like. Examples of alkynyl groups Includes an ethynyl group, a 1-propynyl group, a 1-butynyl group, a trimethylsilylethynyl group, and the like.
Furthermore, in these substituents, R ⁰¹ in the acyl group (R ⁰¹ CO-), a hydrogen atom, and the above-described alkyl group, and an aryl group.

Among these substituents, more preferred are halogen atoms (—F, —Br, —Cl, —I), alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, N-alkylamino groups, N, N -Dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, formyl group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group Group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfa group Moyl group, N-arylsulfur Amoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group, phosphonato group, dialkylphosphono group, diarylphosphono group, monoalkylphosphono group, alkylphosphonato group, monoarylphosphono group, arylphospho Examples thereof include a nato group, a phosphonooxy group, a phosphonatooxy group, an aryl group, and an alkenyl group. In addition, examples of the heterocyclic group include a pyridyl group and a piperidinyl group. Examples of the silyl group include a trimethylsilyl group.

  On the other hand, the alkylene group constituting the substituted alkyl group includes a divalent organic residue obtained by removing any one of the hydrogen atoms on the alkyl group having 1 to 20 carbon atoms. Preferred examples include linear alkylene groups having 1 to 12 carbon atoms, branched alkylene groups having 3 to 12 carbon atoms, and cyclic alkylene groups having 5 to 10 carbon atoms. Preferable specific examples of the substituted alkyl group obtained by combining such an alkylene group and a substituent include chloromethyl group, bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxymethyl group, isopropoxymethyl. Group, butoxymethyl group, s-butoxybutyl group, methoxyethoxyethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, pyridylmethyl group, tetramethylpiperidinylmethyl group, N-acetyl Tetramethylpiperidinylmethyl group, trimethylsilylmethyl group, methoxyethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N-cyclohexylcarbamoyloxye Group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbonylethyl group, allyloxycarbonylbutyl group, Chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl-N- (sulfophenyl) carbamoylmethyl group , Sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfamoylpropyl group, N-methyl-N- (phosphono Enyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphonatobutyl group, tolylphosphonohexyl group, tolylphosphonatohexyl Group, phosphonooxypropyl group, phosphonatoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p-methylbenzyl group, cinnamyl group, allyl group, 1- Examples thereof include a propenylmethyl group, a 2-butenyl group, a 2-methylallyl group, a 2-methylpropenylmethyl group, a 2-propynyl group, a 2-butynyl group, and a 3-butynyl group.

Next, examples of the aryl group as R ¹⁸ and R ¹⁹ include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group. Among these, a phenyl group and a naphthyl group are more preferable.

Examples of the substituted aryl group represented by R ¹⁸ and R ¹⁹ include those having a group consisting of a monovalent non-metallic atomic group excluding a hydrogen atom as a substituent on the ring-forming carbon atom of the aforementioned aryl group. It is done. Examples of preferred substituents include the aforementioned alkyl groups, substituted alkyl groups, and those previously shown as substituents in the substituted alkyl group. Preferred examples of such a substituted aryl group include biphenyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, fluorophenyl group, chloromethylphenyl group, trifluoromethylphenyl group. Hydroxyphenyl group, methoxyphenyl group, methoxyethoxyphenyl group, allyloxyphenyl group, phenoxyphenyl group, methylthiophenyl group, tolylthiophenyl group, ethylaminophenyl group, diethylaminophenyl group, morpholinophenyl group, acetyloxyphenyl group, Benzoyloxyphenyl group, N-cyclohexylcarbamoyloxyphenyl group, N-phenylcarbamoyloxyphenyl group, acetylaminophenyl group, N-methylbenzoylaminophenyl group, cal Xiphenyl group, methoxycarbonylphenyl group, allyloxycarbonylphenyl group, chlorophenoxycarbonylphenyl group, carbamoylphenyl group, N-methylcarbamoylphenyl group, N, N-dipropylcarbamoylphenyl group, N- (methoxyphenyl) carbamoylphenyl group N-methyl-N- (sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoylphenyl group, N-ethylsulfamoylphenyl group, N, N-dipropylsulfamoylphenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phosphonophenyl group, phosphonatophenyl group, diethylphosphonophenyl group, diphenylphosphonophenyl Methylphosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group, tolylphosphonophenyl group, allylphenyl group, 1-propenylmethylphenyl group, 2-butenylphenyl group, 2-methylallylphenyl group, A 2-methylpropenylphenyl group, a 2-propynylphenyl group, a 2-butynylphenyl group, a 3-butynylphenyl group, and the like can be given.

An alkenyl group represented by R ¹⁸ and R ¹⁹ , a substituted alkenyl group, an alkynyl group, and a substituted alkynyl group (—C (R ⁰² ) ═C (R ⁰³ ) (R ⁰⁴ ), and —C≡C (R ^{05 Examples of} )) include those in which R ⁰² , R ⁰³ , R ⁰⁴ and R ⁰⁵ are monovalent non-metallic atomic groups. Preferable examples of R ⁰² , R ⁰³ , R ⁰⁴ and R ⁰⁵ include a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group and a substituted aryl group. Specific examples thereof include those shown as the above examples. More preferable groups of R ⁰² , R ⁰³ , R ⁰⁴ , and R ⁰⁵ include a hydrogen atom, a halogen atom, and a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. Preferable specific examples of the alkenyl group, substituted alkenyl group, alkynyl group and substituted alkynyl group represented by R ¹⁸ and R ¹⁹ include a vinyl group, 1-propenyl group, 1-butenyl group, 1-pentenyl group, 1-hexenyl group, 1-octenyl group, 1-methyl-1-propenyl group, 2-methyl-1-propenyl group, 2-methyl-1-butenyl group, 2-phenyl-1-ethenyl group, 2-chloro- Examples include 1-ethenyl group, ethynyl group, 1-propynyl group, 1-butynyl group, and phenylethynyl group.

Examples of the heterocyclic group represented by R ¹⁸ and R ¹⁹ include the pyridyl group exemplified as the substituent of the substituted alkyl group.

^{Examples of the} substituted sulfonyl group (R ⁰¹¹ —SO ₂ —) represented by R ¹⁸ and R ¹⁹ include those in which R ⁰¹¹ is a group consisting of a monovalent nonmetallic atomic group. More preferable examples include an alkylsulfonyl group and an arylsulfonyl group. Examples of the alkyl group and aryl group in these include those described above as the alkyl group, substituted alkyl group, aryl group, and substituted aryl group. Specific examples of such a substituted sulfonyl group include a butylsulfonyl group, a phenylsulfonyl group, a chlorophenylsulfonyl group, and the like.

In addition, examples of the ring formed by bonding R ¹⁸ and R ¹⁹ in the general formula (F) include morpholine, piperazine, pyrrolidine, pyrrole, indoline and the like. These may be further substituted with a substituent as described above. Among them, the case where an alicyclic ring is formed is preferable.

In the general formula (F), R ¹⁸ and R ¹⁹ are preferably an alkyl group, an alkenyl group, an aryl group, or a substituted sulfonyl group. It is also preferred when R ¹⁸ and R ¹⁹ form an alicyclic ring.

  Specific preferred examples of the monomer or repeating unit having an amide group having a structure represented by the general formula (F) are shown below, but are not limited thereto.

The first binder polymer used for the photosensitive layer in the lithographic printing plate precursor according to the invention includes a copolymer containing the unit represented by the general formula (I) and the unit having a radical polymerizable group in the side chain described above. It is more preferable that the unit is composed of three units: a unit represented by the general formula (I), a unit having a radical polymerizable group in the side chain, and a unit having an amide group in the side chain. Particularly preferred is a polymer.
Although the preferable specific example of a 1st binder polymer is shown below, it is not limited to these.

  The molecular weight of the first binder polymer is appropriately determined from the viewpoints of image formability and printing durability. Usually, when the molecular weight increases, the printing durability is excellent, but the image formability tends to deteriorate. On the contrary, when the molecular weight is low, the image formability is improved, but the printing durability tends to be lowered. The molecular weight is preferably in the range of 2,000 to 1,000,000, more preferably 5,000 to 500,000, and still more preferably 10,000 to 300,000.

The content of the radical polymerizable group in the first binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0 per 1 g of the binder polymer from the viewpoint of sensitivity and storage stability. .1 to 10.0 mmol, more preferably 1.0 to 8.0
mmol, most preferably 2.0 to 7.0 mmol.

  Further, the content of alkali-soluble groups in the first binder polymer (acid value by neutralization titration) is preferably 0.1 to 3.0 mmol per 1 g of the first binder polymer from the viewpoint of developability and printing durability. More preferably, it is 0.2-2.0 mmol, Most preferably, it is 0.3-1.5 mmol.

  In addition, the glass transition point (Tg) of the first binder polymer is preferably 70 to 300 ° C, more preferably 80 to 250 ° C, and most preferably 90 to 200 ° C, from the viewpoint of storage stability and sensitivity. It is a range.

(Second binder polymer)
The second binder polymer contained in the photosensitive layer in the lithographic printing plate precursor according to the invention is an acrylic binder polymer having at least (meth) acrylic acid as a repeating unit. In other words, it is a binder polymer having an acid group-containing repeating unit different from the acid group-containing repeating unit represented by the general formula (I), that is, (meth) acrylic acid, and represented by the general formula (I). The acid group-containing repeating unit is not included.
The second binder polymer may be a polymer composed only of (meth) acrylic acid repeating units, but is usually used as a copolymer in combination with other repeating units. In addition, the repeating unit of (meth) acrylic acid may be only one kind in the 2nd binder polymer, and may contain two kinds.
The total content of repeating units of (meth) acrylic acid in the copolymer is appropriately determined depending on the structure, the design of the photosensitive layer, etc., but preferably 1 to 99 mol% with respect to the total molar amount of the second binder polymer component. More preferably, it is contained in the range of 5 to 40 mol%, and still more preferably in the range of 10 to 30 mol%.

As other repeating units when used as a copolymer, conventionally known ones can be used without limitation as long as they are radically polymerizable monomers. Specific examples include monomers described in “Polymer Data Handbook—Basic Edition” (Edition of Polymer Society, Bafukan, 1986). One type of repeating unit may be used, or two or more types may be used in combination.
For example, the second binder polymer is preferably one having a (meth) acrylic acid ester as a repeating unit. Preferred (meth) acrylic acid esters include methyl (meth) acrylate and ethyl (meth) acrylate.
In addition, the second binder polymer is one of preferable embodiments in which a unit having a radical polymerizable group in the side chain and a unit having a unit having an amide group in the side chain as a repeating unit are also included. About these specific examples, it is the same as what was demonstrated as a preferable copolymerization component of the 1st binder polymer mentioned above.

In particular, the second binder polymer preferably has a repeating unit having a radical polymerizable group in the side chain. The preferred radical polymerizable group is the same as the preferred radical polymerizable group described as the copolymerization component of the first binder polymer described above. More specifically, the α-substituted methylacryl group [—OC (═O) — C (—CH ₂ Z) ═CH ₂ , Z = hydrocarbon group starting from a hetero atom], (meth) acrylic group, allyl group, styryl group and the like, preferably an ethylenically unsaturated bond group, especially an allyl group or a styryl group preferable.

Specific examples of the second binder polymer include [(meth) acrylic acid / other addition polymerizable vinyl monomer as required] copolymer, [(meth) acrylic acid / (meth) acrylic ester / as necessary. Other addition-polymerizable vinyl monomers] copolymer, [(meth) acrylic acid / allyl (meth) acrylate / optional other addition-polymerizable vinyl monomer] copolymer, [(meth) acrylic acid / ( (Meth) acrylic (meth) acrylate / other addition-polymerizable vinyl monomer if necessary] copolymer. These also preferably have a unit having an amide group in the side chain as a repeating unit.

  In order to maintain the developability of the photosensitive layer, the second binder polymer preferably has an appropriate molecular weight and acid value. A high molecular weight polymer having a mass average molecular weight of 5000 to 300000 and an acid value of 20 to 200 meq / g is used. Used effectively.

The compounding ratio of the first binder polymer and the second binder polymer is not particularly limited, but is preferably 10 to 90:90 to 10, more preferably 20 to 80:80 to 20, and 30 A ratio of ˜70: 70-30 is particularly preferred.
In addition to the first binder polymer and the second binder polymer, other known binder polymers may be used in combination with the photosensitive layer. In this case, the total amount of the binder used is preferably 20 to 80% by mass, more preferably 30 to 70% by mass in terms of solid content of the photosensitive layer.

(Polymerizable compound)
The polymerizable compound used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one ethylenically unsaturated bond, preferably two or more. Such a compound group is widely known in the industrial field, and these can be used without particular limitation. These have chemical forms such as monomers, prepolymers, that is, dimers, trimers and oligomers or copolymers thereof, and mixtures thereof. Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.
Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.
Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.
Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, JP-A-59-5241. Those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula to a polyisocyanate compound having two or more isocyanate groups. Can be mentioned.

CH ₂ = C (R ^a ) COOCH ₂ CH (R ^b ) OH
(However, R ^a and R ^b represent H or CH _3. )

Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable. Further, by using addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238, A photopolymerizable composition having very excellent sensitivity can be obtained.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337 and JP-B-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like can also be mentioned. . In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

About these polymerizable compounds, the details of usage, such as the structure, single use or combination, and addition amount can be arbitrarily set according to the final performance design. For example, the use method of the addition polymerizable compound can arbitrarily select an appropriate structure, blending, and addition amount from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface tackiness, and the like.
More specifically, the following viewpoints can be pointed out. From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Also, in order to increase the strength of the image area, that is, the cured film, it should be trifunctional or more, and further, both the photosensitivity and the strength can be adjusted by using different functional numbers and different polymerizable groups in combination. The method is also effective. A compound having a large molecular weight or a compound having high hydrophobicity is excellent in sensitivity and film strength, but is not preferable in terms of development speed and precipitation in a developer. In addition, the selection and use method of the addition polymerization compound is also an important factor for compatibility and dispersibility with other components in the photosensitive layer composition (for example, binder polymer, initiator, colorant, etc.). For example, the compatibility may be improved by using a low-purity compound or using two or more kinds in combination.
In the lithographic printing plate precursor according to the invention, a specific structure may be selected for the purpose of improving adhesion to a support or a protective layer described later. Furthermore, in the lithographic printing plate precursor according to the invention, a layer constitution / coating method such as undercoating or overcoating can be carried out.

Regarding the content of the polymerizable compound in the photosensitive layer composition, the solid content in the photosensitive layer composition is considered from the viewpoints of sensitivity, occurrence of phase separation, adhesiveness of the photosensitive layer, and precipitation in the developer. The amount is preferably 5 to 80% by mass, more preferably 10 to 75% by mass, and particularly preferably 20 to 60% by mass.
In addition, from the viewpoint of suppression of loss of the photosensitive layer, and further from the viewpoints of sensitivity, image forming property, and compatibility, the mass ratio of the polymerizable compound and the total amount of the binder polymer in the photosensitive layer composition is 3: 1 to 1: 3. The range is preferable, the range of 2: 1 to 1: 2 is more preferable, and the range of 1.5: 1 to 1: 1.5 is particularly preferable.

(Polymerization initiator)
The polymerization initiator used in the present invention has a function of initiating and advancing the curing reaction of the above-described polymerizable compound, and is a thermal decomposition type radical generator that decomposes by heat to generate radicals, and excitation of an infrared absorber. Electron transfer type radical generator that accepts electrons and generates radicals, or electron transfer type radical generator that generates electrons by transferring electrons to an excited infrared absorber, and so on to give radicals. Any compound may be used as long as it is generated. Examples include onium salts, triazine compounds having a trihalomethyl group, peroxides, azo polymerization initiators, azide compounds, quinonediazides, active halogen compounds, oxime ester compounds, triaryl monoalkylborate compounds, etc. It is not limited to.
The polymerization initiator used here is preferably an onium salt, an active halogen compound, an oxime ester compound, a borate compound, etc. from the viewpoint of high sensitivity and storage stability, and in particular, a sulfonium salt, an iodonium salt, and a diazonium salt. An onium salt such as is more preferably used.

  Particularly preferred sulfonium salts include onium salts represented by the following general formula (1).

In the general formula (1), R ¹¹ , R ¹² and R ¹³ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms. (Z ¹¹ ) ⁻ represents a counter ion selected from the group consisting of halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, carboxylate ion, and sulfonate ion, preferably perchloric acid Ions, hexafluorophosphate ions, carboxylate ions, and aryl sulfonate ions.

  Specific examples ([OS-1] to [OS-12]) of the onium salt represented by the general formula (1) are shown below, but are not limited thereto.

  In addition to the above, specific aromatic sulfonium salts described in JP-A Nos. 2001-133696, 2002-148790, 2002-148790, 2002-350207, and 2002-6482 are also included. Preferably used.

  Examples of the iodonium salt and diazonium salt that are particularly preferably used include those represented by the following general formulas (2) and (3).

In the general formula (2), Ar ²¹ and Ar ²² each independently represent an aryl group having 20 or less carbon atoms which may have a substituent. Preferred substituents when this aryl group has a substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or a carbon atom having 12 or less carbon atoms. An aryloxy group is mentioned. (Z ²¹ ) ⁻ represents a counter ion having the same meaning as (Z ¹¹ ) ⁻ .

In General Formula (3), Ar ³¹ represents an aryl group having 20 or less carbon atoms, which may have a substituent. Preferred examples of the substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, an aryloxy group having 12 or less carbon atoms, and 12 or less carbon atoms. Examples thereof include an alkylamino group, a dialkylamino group having 12 or less carbon atoms, an arylamino group having 12 or less carbon atoms, or a diarylamino group having 12 or less carbon atoms. (Z ³¹ ) ⁻ represents a counter ion having the same meaning as (Z ¹¹ ) ⁻ .

  The onium salts ([OI-1] to [OI-10]) represented by the general formula (2) and the onium salts represented by the general formula (3) ([ON-1]) that can be suitably used. Specific examples of [ON-5]) are given, but the invention is not limited to these.

  When the planographic printing plate precursor is handled under white light, the polymerization initiator (radical generator) preferably has a maximum absorption wavelength of 400 nm or less, and more preferably 360 nm or less.

  The content of the polymerization initiator is from 0.1 to 50% by mass, preferably from 0.5 to 30% by mass, based on the total solid content constituting the photosensitive layer, from the viewpoint of sensitivity and occurrence of smudges in the non-image area during printing. %, Particularly preferably 1 to 20% by mass.

Moreover, only 1 type may be used for a polymerization initiator and it may use 2 or more types together. When two or more polymerization initiators are used in combination, for example, a plurality of suitably used onium salt polymerization initiators may be used, or an onium salt polymerization initiator and another polymerization initiator may be used in combination. Also good. When the onium salt polymerization initiator and another polymerization initiator are used in combination, the content ratio (mass ratio) is preferably 100/1 to 100/50, and more preferably 100/5 to 100/25.
The polymerization initiator may be added to the same layer as other components, or another layer may be provided and added thereto.

  Here, for example, when an onium salt polymerization initiator is used as the polymerization initiator, since the sensitivity is high, the radical polymerization reaction proceeds effectively, and the strength of the formed image portion becomes very high. Therefore, combined with the high oxygen blocking function of the protective layer described later, a lithographic printing plate having high image area strength can be produced, and as a result, printing durability is further improved. Further, since the onium salt polymerization initiator itself is excellent in stability over time, even when the prepared lithographic printing plate precursor is stored, it is possible to effectively suppress the occurrence of an undesirable polymerization reaction. It will also have.

(Infrared absorber)
The infrared absorber suitably used in the present invention will be described in detail.
The infrared absorber used is highly sensitive to infrared laser irradiation (exposure) and is in an electronically excited state. Electron transfer, energy transfer, heat generation (photothermal conversion function), and the like related to the electron excited state are present in the photosensitive layer. It is presumed that it acts on a coexisting polymerization initiator to cause a chemical change in the polymerization initiator to generate a radical. In any case, the addition of an infrared absorber is particularly suitable for plate making directly drawn with an infrared laser beam having a wavelength of 750 nm to 1400 nm, and exhibits higher image forming properties than conventional lithographic printing plate precursors. can do.

  The infrared absorber is preferably a dye or pigment having an absorption maximum at a wavelength of 750 nm to 1400 nm.

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, dyes such as 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, etc. Is mentioned.
Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, 58-181690, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59- No. 73996, JP-A-60-52940, JP-A-60-63744 and the like, Naphthoquinone dyes described in JP-A-58-112792, etc., British Patent 434,875 And cyanine dyes.

  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. . Moreover, as another example preferable as a dye, the near-infrared absorptive dye described as the formula (I) and (II) in US Patent 4,756,993 can be mentioned.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (a).

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, a nitrogen 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 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. Xa ^- the Za described later ^- is defined as for, 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 photosensitive layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

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

  Specific examples of the cyanine dye represented by the general formula (a) that can be suitably used include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969.

  More particularly preferred examples include specific indolenine cyanine dyes described in JP-A-2002-278057 as exemplified below.

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

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and 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.

  The pigment may be used without being surface-treated or may be used after being surface-treated. 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 size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. Within such a particle size range, excellent dispersion stability of the pigment in the photosensitive layer can be obtained, and a uniform photosensitive layer can be formed.

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).

  The infrared absorber may be added to the same layer as other components, or another layer may be provided and added thereto.

  From the viewpoint of uniformity in the photosensitive layer and durability of the photosensitive layer, the infrared absorbent is 0.01 to 50% by mass, preferably 0.1 to 10% by mass, based on the total solid content constituting the photosensitive layer. In the case of, it is particularly preferably 0.5 to 10% by mass, and in the case of a pigment, particularly preferably 0.1 to 10% by mass.

(Other ingredients)
In addition to the above components, other components known in the art suitable for the use, production method and the like can be appropriately added to the photosensitive layer. Hereinafter, preferred additives are exemplified.

-Colorant-
A dye or pigment may be added for the purpose of coloring the photosensitive layer. Thereby, in the printing plate after plate making, what is called plate inspection property, such as image visibility and image density measuring device suitability, can be improved. Specific examples of the colorant include pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes. Among them, a cationic dye is preferable.
The addition amount of the dye and the pigment as the colorant is preferably about 0.5% by mass to about 5% by mass with respect to the solid content in the photosensitive layer composition.

-Polymerization inhibitor-
In order to prevent unnecessary thermal polymerization of a polymerizable compound having an ethylenically unsaturated double bond, that is, a polymerizable compound, it is desirable to add a small amount of a thermal polymerization inhibitor. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol ), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the solid content in the photosensitive layer composition. If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide or the like may be added to prevent polymerization inhibition by oxygen and may be unevenly distributed on the surface of the layer in the course of drying after coating. The addition amount of the higher fatty acid derivative is preferably about 0.5% by mass to about 10% by mass with respect to the solid content in the photosensitive layer composition.

-Other additives-
Furthermore, known additives such as an inorganic filler for improving the physical properties of the cured film, a plasticizer, and a sensitizer capable of improving the ink inking property on the surface of the photosensitive layer may be added to the photosensitive layer. . Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin, and the like. Binder polymer and polymerizable compound In general, it can be added in a range of 10% by mass or less with respect to the total mass.
In addition, for the purpose of improving the film strength (printing durability) of the resulting lithographic printing plate, or in order to enhance the effect of heating and exposure after development, a UV polymerization initiator, a thermal crosslinking agent, etc. are also added. It is also possible.

<Protective layer>
Next, the protective layer provided on the photosensitive layer will be described in detail.
It is desirable that the protective layer does not substantially inhibit the transmission of light used for exposure, has excellent adhesion to the image recording layer, and can be easily removed in a development process after exposure. Such a device relating to the protective layer has been conventionally made and is described in detail in US Pat. No. 3,458,311 and JP-A-55-49729.
Further, since the negative lithographic printing plate precursor in the present invention has a design of a polymerization type photosensitive layer, the negative lithographic printing plate precursor has an oxygen blocking ability that blocks oxygen in the atmosphere during exposure and exhibits a polymerization inhibiting action. Is desirable. On the other hand, it is also desirable to have an oxygen permeation ability that exhibits an effect of preventing dark polymerization from the viewpoint of stability during storage or suitability for safelight, and a protective layer having a low oxygen barrier property to the extent that it has both functions. Is desirable.

(Water-soluble polymer compound)
As a material used as a main component for the protective layer, it is preferable to use a water-soluble polymer compound having relatively excellent crystallinity. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic Water-soluble polymers such as polyacrylic acid are well known in the art. Of these, the use of polyvinyl alcohol as the main component gives the best results for basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having the required oxygen barrier properties and water solubility. . Similarly, a part of the copolymer may have other repeating units.
Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC made by Kuraray Co., Ltd. , PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA -420, PVA-613, L-8 and the like. Examples of the copolymer include 88-100% hydrolyzed polyvinyl acetate chloroacetate or propionate, polyvinyl formal, polyvinyl acetal, and copolymers thereof. Other useful water-soluble polymer compounds include polyvinylpyrrolidone, gelatin and gum arabic, and these may be used alone or in combination.

Examples of the polyvinyl alcohol suitably used in the present embodiment include those having a saponification degree of 71 to 100% and a molecular weight of 200 to 2400. It is more preferable to use polyvinyl alcohol having a saponification degree of 91 mol% or more from the viewpoint of good oxygen barrier properties, excellent film forming properties and a low adhesion surface.
Specifically, PVA-102, PVA-103, PVA-104, PVA-105, PVA-110, PVA-117, PVA-120, PVA-124, PVA-117H, PVA-135H made by Kuraray Co., Ltd. , PVA-HC, PVA-617, PVA-624, PVA-706, PVA-613, PVA-CS, PVA-CST, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenol NL-05, NM-11, NM-14 , AL-06, P-610, C-500, A-300, AH-17, JF-04, JF-05, JF-10, JF-17, JF-17L, manufactured by Nihon Venture Bipoval Co., Ltd. , JM-05, JM-10, JM-17, JM-17L, JT-05, JT-13, JT-15 and the like.

Furthermore, what acid-modified polyvinyl alcohol is also used suitably. Specifically, itaconic acid and maleic acid-modified carboxy-modified polyvinyl alcohol and sulfonic acid-modified polyvinyl alcohol are preferable. These acid-modified polyvinyl alcohols having a saponification degree of 91 mol% or more can be more preferably used.
Specific examples of the acid-modified polyvinyl alcohol include KL-118, KM-618, KM-118, SK-5102, MP-102, R-2105, manufactured by Kuraray Co., Ltd., and Nippon Synthetic Chemical Industry Co., Ltd. , GOHSENAL CKS-50, T-HS-1, T-215, T-350, T-330, T-330H, AF-17, AT-17, etc. manufactured by Nihon Ventures & Poval Co., Ltd. are included.

The above water-soluble polymer compound is 45 to 95% by mass with respect to the total solid content in the protective layer, considering the sensitivity of the obtained lithographic printing plate precursor and the adhesion between the lithographic printing plate plates when laminated. It is preferable to contain in the range of 50-90 mass%, and it is more preferable to contain.
As the water-soluble polymer compound, at least one kind may be used, and a plurality of kinds may be used in combination. Even when a plurality of types of water-soluble polymer compounds are used in combination, the total amount is preferably in the above-described mass range.

  On the other hand, in the protective layer, adhesion to the image area of the photosensitive layer and uniformity of the film are also extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesive force is likely to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563 disclose an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and the like and laminating on the photosensitive layer. Of course, any of these known techniques can be applied.

  Polyvinyl alcohol and polyvinyl pyrrolidone may be used in combination in the protective layer from the viewpoint of adhesive strength with the photosensitive layer, sensitivity, and the occurrence of unnecessary fog. In this case, the addition ratio (mass ratio) of polyvinyl alcohol / polyvinylpyrrolidone having a saponification degree of 91 mol% or more is preferably 3/1 or less. In addition to polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and copolymers thereof having relatively excellent crystallinity can be used in combination with polyvinyl alcohol.

(Inorganic layered compound)
The protective layer of the present invention preferably contains an inorganic layered compound. By using an inorganic stratiform compound in combination, the oxygen barrier property is further increased, and the film strength of the protective layer is further improved to improve scratch resistance, and matte properties can be imparted to the protective layer.
As a result, the protective layer can suppress deterioration due to deformation or the like and generation of scratches in addition to the above-described barrier property against oxygen or the like. Further, by providing matte properties to the protective layer, when the lithographic printing plate precursor is laminated, it is possible to suppress adhesion between the protective layer surface of the lithographic printing plate precursor and the back surface of the adjacent lithographic printing plate precursor support. It becomes possible.

Examples of the inorganic layered compound include, for example, the general formula: A (B, C) ₂ -5D ₄ O ₁₀ (OH, F, O) ₂ [where A is any of K, Na, Ca, B and C Is any one of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica compounds such as natural mica and synthetic mica.

In the mica compound, examples of natural mica include muscovite, soda mica, phlogopite, biotite, and sericite. Synthetic mica includes non-swelling mica such as fluorine phlogopite mica ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 (Si ₄ O ₁₀ ) F ₂ , and Na tetrasilicic mica NaMg _2.5. (Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , montmorillonite Na or Li hectorite (N
a, Li) _1/8 Mg _2/5 Li _1/8 (Si ₄ O ₁₀ ) F _{2 and} other swellable mica. In addition, synthetic smectites are also useful.

Of the mica compounds, fluorine-based swellable mica is particularly useful. That is, this swellable synthetic mica has a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and the substitution of metal atoms in the lattice is significantly larger than other viscosity minerals. As a result, the lattice layer is deficient in positive charges, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers in order to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between the layers is Li ⁺ or Na ⁺ , since the ionic radius is small, the bond between the layered crystal lattices is weak, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Swellable synthetic mica has a strong tendency and is useful in the present embodiment. In particular, swellable synthetic mica is preferably used.

  The shape of the mica compound is preferably as small as possible from the viewpoint of diffusion control, and the plane size is preferably as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured from, for example, a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  The average major axis of the mica compound is 0.3 to 20 μm, preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. Specifically, for example, the swellable synthetic mica that is a representative compound has a thickness of 1 to 50 nm and a surface size (major axis) of about 1 to 20 μm.

  The amount contained in the protective layer of the inorganic stratiform compound is from the viewpoint of suppression of adhesion between lithographic printing plate precursors when they are laminated, suppression of scratches, sensitivity reduction due to blocking during laser exposure, low oxygen permeability, etc. The total solid content of the protective layer is preferably in the range of 5 to 50% by mass, particularly preferably in the range of 10 to 40% by mass. Even when a plurality of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass.

Components of the protective layer (selection of polyvinyl alcohol and inorganic layered compounds, use of additives), coating amount, etc. are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability The
The protective layer in the present invention preferably has an oxygen permeability at 25 ° C.-1 atm of 0.5 ml / m ² · day to 100 ml / m ² · day, so that such oxygen permeability is achieved. Further, it is preferable to adjust the coating amount.

  The protective layer may be added with a colorant (water-soluble dye) that is excellent in light transmittance used when exposing the photosensitive layer and that can efficiently absorb light having a wavelength not related to exposure. Good. Thereby, safelight aptitude can be improved, without reducing a sensitivity.

(Formation of protective layer)
The method for applying the protective layer is not particularly limited, and is carried out by applying an aqueous protective layer coating solution containing the above-described components onto the photosensitive layer. For example, the method described in US Pat. No. 3,458,311 or JP-A-55-49729 can also be applied.

Hereinafter, a method for applying a protective layer containing an inorganic layered compound such as a mica compound and a water-soluble polymer compound such as polyvinyl alcohol will be described in detail. A dispersion in which an inorganic layered compound such as a mica compound is dispersed is prepared, and the dispersion is mixed with a water-soluble polymer compound such as polyvinyl alcohol (or an aqueous solution in which a water-soluble polymer compound is dissolved). A protective layer is formed by applying a coating solution for protective layer formed on the photosensitive layer.
An example of a method for dispersing an inorganic layered compound such as a mica compound used in the protective layer will be described. First, 5 to 10 parts by mass of the swellable mica compound mentioned above as a preferable mica compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen, and then dispersed by a disperser. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. In general, a 2 to 15% by mass dispersion of the mica compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a coating solution for a protective layer using this dispersion, after diluting with water and stirring sufficiently, a water-soluble polymer compound such as polyvinyl alcohol (or a water-soluble polymer compound such as polyvinyl alcohol) is added. It is preferable to prepare by blending with a dissolved aqueous solution.

  Known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the resulting film can be added to the protective layer coating solution. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, known additives for improving the adhesion to the photosensitive layer and the temporal stability of the coating solution may be added to the coating solution.

The coating amount of the protective layer is 0.1 g / m ² to 4 in terms of maintaining the film strength and scratch resistance of the protective layer obtained, maintaining the image quality, and maintaining appropriate oxygen permeability for imparting safelight suitability. 0.0 g / m ² is preferable, and 0.3 g / m ^{2 to} 3.0 g / m ² is more preferable.

<Substrate (support)>
Examples of the support used in the present invention include paper, a polyester film or an aluminum plate. Among them, the dimensional stability is good, the cost is relatively low, and the surface treatment according to need is excellent in hydrophilicity and strength. An aluminum plate capable of providing a rough surface is preferred. A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

  The aluminum plate here is a metal plate mainly composed of dimensionally stable aluminum. In addition to a pure aluminum plate, an aluminum plate containing aluminum as a main component and containing a trace amount of foreign elements, or aluminum (alloy) ) Means to include a laminated or vapor-deposited plastic film or paper. In the following description, the above-mentioned support made of aluminum or an aluminum alloy is generically used as an aluminum support. 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 10% by mass or less. Of these, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and may contain a slightly different element. Thus, the composition of the aluminum plate is not specified, and conventionally known and used materials such as JIS A 1050, JIS A 1100, JIS A 3103, and JIS A 3005 can be appropriately used. it can.

The thickness of the aluminum support is about 0.1 mm to 0.6 mm. This thickness can be changed as appropriate according to the size of the printing press, the size of the printing plate, and the desire of the user.
Such an aluminum support is subjected to the following surface treatment to make it hydrophilic.

(Roughening treatment)
Examples of the roughening treatment method include mechanical roughening, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Furthermore, the electrochemical surface roughening method in which the surface is electrochemically roughened in hydrochloric acid or nitric acid electrolyte solution, the aluminum surface is scratched with a metal wire, the wire brush grain method, the surface of the aluminum is polished with a polishing ball and an abrasive. A mechanical graining method such as a pole grain method, a brush grain method in which the surface is roughened with a nylon brush and an abrasive, can be used, and the above roughening methods can be used alone or in combination. Among them, a method usefully used for roughening is an electrochemical method in which roughening is performed chemically in hydrochloric acid or nitric acid electrolyte, and a suitable amount of electricity at the time of anode is 50 C / dm ^{2 to} 400 C / dm ² . It is a range. More specifically, in the electrolytic solution containing from 0.1 to 50% hydrochloric acid or nitric acid, the temperature 20 to 80 ° C., for 1 second to 30 minutes, alternating at a current density of 100C / dm ² ~400C / dm ² It is preferable to perform direct current electrolysis.

  The roughened aluminum support may be chemically etched with acid or alkali. Etching agents suitably used are caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like, and preferred ranges of concentration and temperature are 1 to 50% and 20%, respectively. ~ 100 ° C. Pickling is performed to remove dirt (smut) remaining on the surface after etching. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid and the like are used. In particular, as a method for removing smut after the electrochemical surface roughening treatment, contact with 15 to 65 mass% sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739 is preferable. And the alkali etching method described in Japanese Patent Publication No. 48-28123. After the treatment as described above, the method and conditions are not particularly limited as long as the surface roughness Ra of the treated surface is about 0.2 to 0.5 μm.

(Anodizing treatment)
The aluminum support that has been treated as described above to form an oxide layer is then anodized.
In the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, or an aqueous solution of boric acid / sodium borate is used alone or in combination as a main component of the electrolytic bath. In this case, the electrolyte solution may of course contain at least components normally contained in at least an Al alloy plate, an electrode, tap water, groundwater and the like. Further, the second and third components may be added. Here, the second and third components are, for example, metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and ammonium ions. Examples include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions and the like, and the concentration is 0 to 10,000 ppm. May be included. There are no particular limitations on the conditions of the anodizing treatment, but the treatment is preferably carried out by direct current or alternating current electrolysis at a current density of 0.1 to 40 A / m ² at 30 to 500 g / liter, a treatment liquid temperature of 10 to 70 ° C. . The thickness of the formed anodic oxide film is in the range of 0.5 to 1.5 μm. Preferably it is the range of 0.5-1.0 micrometer. The support prepared by the above treatment is treated so that the pore diameter of the micropores existing in the anodized film is in the range of 5 to 10 nm and the pore density is in the range of 8 × 10 ¹⁵ to 2 × 10 ¹⁶ pieces / m ^2. It is preferred that the conditions are selected.

A widely known method can be applied as the hydrophilic treatment of the support surface. As a particularly preferable treatment, a hydrophilic treatment with silicate or polyvinylphosphonic acid is performed. The film is S
The i or P element amount is ^{2 to} 40 mg / m ² , more preferably 4 to 30 mg / m ² . The coating amount can be measured by fluorescent X-ray analysis.

  The hydrophilization treatment is carried out by applying an anodized film to an aqueous solution containing 1 to 30% by mass, preferably 2 to 15% by mass of alkali metal silicate or polyvinylphosphonic acid, and having a pH of 10 to 13 at 25 ° C. This is carried out by immersing the aluminum support on which is formed, for example, at 15 to 80 ° C. for 0.5 to 120 seconds.

  As the alkali metal silicate used for the hydrophilization treatment, sodium silicate, potassium silicate, lithium silicate, or the like is used. Examples of the hydroxide used for increasing the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend alkaline-earth metal salt or a group IVB metal salt with said process liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble substances such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Salt. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, potassium titanium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, etc. Can be mentioned.

  Alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. A preferable range of these metal salts is 0.01 to 10% by mass, and a more preferable range is 0.05 to 5.0% by mass. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. A surface obtained by combining a support subjected to electrolytic grain as disclosed in JP-B-46-27481, JP-A-52-58602, and JP-A-52-30503 with the above-described anodizing treatment and hydrophilization treatment. Processing is also useful.

[Preparation of lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention has a photosensitive layer and a protective layer in this order on a support, and an intermediate layer (undercoat layer) or the like may be further provided as necessary. Such a lithographic printing plate precursor can be produced by sequentially coating a coating liquid containing the above-described various components on a support.

When coating the photosensitive layer, the photosensitive layer components are dissolved in various organic solvents to form a photosensitive layer coating solution, which is applied onto the support or the undercoat layer.
Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, lactic acid There are ethyl and the like. These solvents can be used alone or in combination. The solid content in the photosensitive layer coating solution is suitably 2 to 50% by mass.

The coating amount of the photosensitive layer mainly affects the sensitivity of the photosensitive layer, the strength of the exposed film, the developability, and the printing durability of the resulting printing plate, and is preferably selected as appropriate according to the application. In the case of a lithographic printing plate precursor for scanning exposure, the coating amount is preferably in the range of about 0.1 g / m ² to about 10 g / m ² in terms of mass after drying. More preferably from 0.5 to 5 g / m ^2.

[Intermediate layer (undercoat layer)]
The above lithographic printing plate precursor may be provided with an intermediate layer (undercoat layer) for the purpose of improving the adhesion and soiling between the photosensitive layer and the support. Specific examples of such an intermediate layer include JP-B-50-7481, JP-A-54-72104, JP-A-59-101651, JP-A-60-149491, JP-A-60-232998, JP-A-3-56177, JP-A-4-282737, JP-A-5-16558, JP-A-5-246171, JP-A-7-159983, JP-A-7-314937, JP-A-8-202025, Special Kaihei 8-320551, JP 9-34104, JP 9-236911, JP 9-269593, JP 10-69092, JP 10-115931, JP 10-161317, JP 10-260536, JP-A-10-282682, JP-A-11-84684, JP-A-10-69092, JP-A-10-115931, Kaihei 11-38635, JP-A-11-38629, JP-A-10-282645, JP-A-10-301262, JP-A-11-24277, JP-A-11-109641, JP-A-10-319600, JP-A-10-319600 11-84684, JP-A-11-327152, JP-A-2000-10292, JP-A-2000-235254, JP-A-2000-352854, JP-A-2001-209170, JP-A-2001-175001, etc. Things can be mentioned.

<Plate making method>
Hereinafter, the plate making method of the lithographic printing plate precursor according to the invention will be described.
A method for making a lithographic printing plate precursor is, for example, by stacking a plurality of the above-described lithographic printing plate precursors in a state where the protective layer and the back surface of the support are in direct contact with each other, and setting this in a plate setter. The lithographic printing plate precursors are automatically conveyed one by one, exposed to an image at a wavelength of 750 nm to 1400 nm, and then subjected to a development process to remove the non-image area and complete the plate making process. The lithographic printing plate precursor according to the present invention suppresses the adhesion between the lithographic printing plate precursors and the generation of scratches on the protective layer even if it is a laminate without interposing the interleaving paper in the middle. Can be applied to the method. According to this plate making method, a laminated body obtained by superposing planographic printing plate precursors without interposing the interleaving paper is used, so that the interleaving paper removing step is unnecessary and productivity in the plate making step is improved.
Of course, the lithographic printing plate precursor of the present invention may be made using a laminate obtained by alternately laminating with interleaving paper.

〔exposure〕
The light source used for the exposure process may be any light source that can be exposed at a wavelength of 750 nm to 1400 nm, but an infrared laser is preferable. In particular, image exposure is preferably performed by a solid-state laser or a semiconductor laser that emits infrared rays having a wavelength of 750 nm to 1400 nm. The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec. The amount of energy per unit irradiated on the lithographic printing plate precursor is preferably 10 to 300 mJ / cm ² .

In this exposure processing, exposure can be performed by overlapping the light beams of the light sources. Overlap means that exposure is performed under the condition that the sub-scanning pitch width is smaller than the beam diameter. The overlap can be expressed quantitatively by FWHM / sub-scanning pitch width (overlap coefficient), for example, when the beam diameter is expressed by the half width (FWHM) of the beam intensity. In the present invention, this overlap coefficient is preferably 0.1 or more.

  The light source scanning method of the exposure apparatus is not particularly limited, and a cylindrical outer surface scanning method, a cylindrical inner surface scanning method, a planar scanning method, and the like can be used. The channel of the light source may be a single channel or a multi-channel, but in the case of a cylindrical outer surface system, a multi-channel is preferably used.

  The plate making of the lithographic printing plate precursor according to the present invention can be subjected to development processing without performing special heat treatment and / or water washing treatment that is usually performed after exposure processing. By not performing this heat treatment, image non-uniformity due to the heat treatment can be prevented. In addition, by performing no heat treatment and / or water washing treatment, stable high-speed processing is possible in development processing.

〔developing〕
Hereinafter, the developer used in the development process performed after the exposure process will be described.

<Developer>
The developer to be used is not particularly limited, but usually an alkaline aqueous solution containing an alkali agent and having a pH of 14 or less is applied.

(Alkaline agent)
Examples of the alkaline agent used in the developer include trisodium phosphate, potassium, ammonium, sodium borate, potassium, ammonium, sodium hydroxide, potassium, ammonium, and lithium. Inorganic alkaline agent and monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, di Examples include organic alkali agents such as isopanolamine, ethyleneimine, ethylenediamine, pyridine, and tetramethylammonium hydroxide. These may be used alone or in combination of two or more.

  Moreover, alkali silicate can be mentioned as alkali agents other than the above. Alkali silicates may be used in combination with a base. The alkali silicate to be used exhibits alkalinity when dissolved in water, and examples thereof include sodium silicate, potassium silicate, lithium silicate, and ammonium silicate. These alkali silicates may be used alone or in combination of two or more.

When silicate is used, the mixing ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali oxide M ₂ O (M represents an alkali metal or ammonium group) as an alkali component are adjusted. Thus, the developer characteristics can be easily adjusted within the optimum range. The mixing ratio (SiO ₂ / M ₂ O molar ratio) of silicon oxide SiO ₂ and alkali oxide M ₂ O is the amount of unclean dirt caused by excessive dissolution (etching) of the anodic oxide film of the support. From the viewpoint of suppressing the generation of insoluble gas resulting from complex formation between dissolved aluminum and silicate, the range is preferably 0.75 to 4.0, more preferably 0.75 to 3.5. Used in.

The concentration of the alkali silicate in the developer includes the effect of suppressing the dissolution (etching) of the anodic oxide film on the support, the developability, the effect of suppressing precipitation and crystal formation, and the gel during neutralization during waste liquid treatment. From the standpoint of the anti-oxidation effect, etc., the amount of SiO ₂ is preferably 0.01 to 1 mol / L, more preferably 0.05 to 0.8 mol / L with respect to the mass of the developer.

(Aromatic anionic surfactant)
The developer preferably contains an aromatic anionic surfactant from the viewpoints of development promotion effect, dispersion stabilization of the negative polymerizable photosensitive layer component and protective layer component in the developer, and development processing stabilization.
The aromatic anionic surfactant is not particularly limited, but is preferably a compound represented by the following general formula (A) or general formula (B).

In the above general formula (A) or general formula (B), R ¹ and R ³ each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, specifically an ethylene group. , Propylene group, butylene group, pentylene group, and the like, among which ethylene group and propylene group are particularly preferable.
m and n each independently represent an integer selected from 1 to 100. Among them, 1 to 30 are preferable, and 2 to 20 are more preferable. When m is 2 or more, a plurality of R ¹ may be the same or different. Similarly, when n is 2 or more, a plurality of R ³ may be the same or different.
t and u each independently represents 0 or 1.

R ² and R ⁴ each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, hexyl group, dodecyl group Among them, a methyl group, an ethyl group, an iso-propyl group, an n-propyl group, an n-butyl group, an iso-butyl group, and a tert-butyl group are particularly preferable.
p and q each represent an integer selected from 0 to 2; Y ¹ and Y ² each represent a single bond or an alkylene group having 1 to 10 carbon atoms. Specifically, a single bond, a methylene group or an ethylene group is preferred, and a single bond is particularly preferred.
(Z ¹ ) ^{r +} and (Z ² ) ^{s +} each independently represents an alkali metal ion, an alkaline earth metal ion, or an ammonium ion that is unsubstituted or substituted with an alkyl group. Sodium ion, potassium ion, magnesium ion, calcium ion, ammonium ion, secondary to quaternary ammonium ion substituted with an alkyl group, aryl group or aralkyl group having 20 or less carbon atoms, particularly sodium ion Is preferred. r and s each represent 1 or 2.
Specific examples of the aromatic anionic surfactant are shown below, but are not limited thereto.

  Aromatic anionic surfactants may be used singly or in appropriate combination of two or more. The addition amount of the aromatic anionic surfactant is not particularly limited, but considering the developability, the solubility of the photosensitive layer component and the protective layer component, and the printing durability of the resulting printing plate, The concentration of the aromatic anionic surfactant is preferably in the range of 1.0 to 10% by mass, more preferably in the range of 2 to 10% by mass.

In addition to the aromatic anionic surfactant, other surfactants may be used in combination with the developer. Examples of other surfactants include polyoxyethylene naphthyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, Polyoxyethylene alkyl esters such as oxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, sorbitan alkyl esters, glycerol mono Nonionic surfactants such as monoglyceride alkyl esters such as stearate and glycerol monooleate can be mentioned.
The content of these other surfactants in the developer is preferably from 0.1 to 10% by mass.

(Chelating agent)
For example, the developer preferably contains a chelating agent for a divalent metal in order to suppress the influence of calcium ions contained in hard water. Examples of the chelating agent for the divalent metal include Na ₂ P ₂ O ₇ , Na ₅ P ₃ O ₃ , Na ₃ P ₃ O ₉ , Na ₂ O ₄ P (NaO ₃ P) PO ₃ Na ₂ , Calgon (polymetaline). Polyphosphates such as ethylenediaminetetraacetic acid, its potassium salt, its sodium salt, its amine salt; diethylenetriaminepentaacetic acid, its potassium salt, sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt Hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its potassium salt, its sodium salt; 1,2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt; 1,3-diamino-2 -Propanol tetraacetic acid, its potassium salt, 2-phosphonobutanetricarboxylic acid-1,2,4, potassium salt thereof, sodium salt thereof; 2-phosphonobutanone tricarboxylic acid-2,3,4, 1-phosphonoethanetricarboxylic acid-1,2,2, potassium salt, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri Organic phosphonic acids such as (methylenephosphonic acid), its potassium salt, its sodium salt and the like, among others, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt, its amine salt; ethylenediaminetetra (methylenephosphonic acid) ), Its ammonium salt, its potassium salt; hexamethyl Emissions diamine tetra (methylene phosphonic acid), an ammonium salt, its potassium salt is preferred.
The optimum amount of such a chelating agent varies depending on the hardness of the hard water used and the amount used, but is generally 0.01 to 5% by mass, more preferably 0% in the developing solution at the time of use. It is used in the range of 0.01 to 0.5% by mass.

  In addition, an alkali metal salt of an organic acid or an alkali metal salt of an inorganic acid may be added to the developer as a development regulator. For example, sodium carbonate, potassium, ammonium, sodium citrate, potassium, ammonium and the like may be used alone or in combination of two or more.

  In addition to the above components, the following components can be used in the developer as necessary. For example, benzoic acid, phthalic acid, p-ethylbenzoic acid, pn-propylbenzoic acid, p-isopropylbenzoic acid, pn-butylbenzoic acid, pt-butylbenzoic acid, pt-butylbenzoic acid Acids, organic carboxylic acids such as p-2-hydroxyethylbenzoic acid, decanoic acid, salicylic acid, 3-hydroxy-2-naphthoic acid; organic solvents such as propylene glycol; in addition, reducing agents, dyes, pigments, preservatives, etc. Is mentioned.

The pH of the developer is the ability to develop non-image areas and reduce damage to image areas during development.
Furthermore, from the viewpoint of the handling property of the developer, the pH at 25 ° C. is preferably in the range of 10 to 12.5, and more preferably in the range of pH 11 to 12.5.

  The conductivity x of the developer is preferably 2 <x <30 mS / cm, and more preferably 5 to 25 mS / cm. In order to adjust the conductivity, it is preferable to add an alkali metal salt of an organic acid, an alkali metal salt of an inorganic acid, or the like as a conductivity adjusting agent.

  The developer can be used as a developer and a development replenisher for the exposed lithographic printing plate precursor, and is preferably applied to an automatic processor. When developing using an automatic developing machine, the developing solution becomes fatigued according to the amount of processing, so that the processing capability may be restored by using a replenishing solution or a fresh developing solution. This replenishment method is also preferably applied to the plate making method in the present invention.

  Furthermore, it is also possible to apply replenishment by the method described in US Pat. No. 4,882,246 in order to restore the processing capacity of the developing solution using an automatic developing machine. In addition, the developers described in JP-A-50-26601, 58-54341, JP-B-56-39464, 56-42860, and 57-7427 are also applicable.

  The lithographic printing plate precursor thus developed is subjected to washing water, surface activity as described in JP-A Nos. 54-8002, 55-11545, 59-58431, and the like. A method of post-treatment with a rinsing solution containing an agent or the like, a desensitizing solution containing gum arabic, a starch derivative or the like is also applicable, and these treatments can be used in various combinations.

  Furthermore, for the purpose of improving the image strength and printing durability, it is also possible to apply full-surface heating or full-exposure to the developed image. For the heating after the development, very strong conditions can be used. Usually, the heating temperature is 200 to 500 ° C.

The planographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.
As a plate cleaner used for removing stains on the plate during printing, a conventionally known plate cleaner for PS plate is used. For example, multi cleaner, CL-1, CL-2, CP, CN -4, CN, CG-1, PC-1, SR, IC (manufactured by Fuji Photo Film Co., Ltd.) and the like.

EXAMPLES Hereinafter, although an Example demonstrates this invention, it is not specifically limited to these.
[Example 1]
(Production of support)
The surface treatment shown below was performed using a JIS A 1050 aluminum plate having a thickness of 0.30 mm and a width of 1030 mm.

<Surface treatment>
In the surface treatment, the following various treatments (a) to (f) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) The aluminum plate was etched with an aqueous solution having a caustic soda concentration of 26 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. to dissolve the aluminum plate by 5 g / m ² . Thereafter, it was washed with water.

(B) A desmut treatment by spraying was performed with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (including 0.5% by mass of aluminum ions), and then washed with water.

(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (including 0.5% by mass aluminum ions and 0.007% by mass ammonium ions) at a temperature of 30 ° C. The AC power source was subjected to 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 2 msec until the current value reached a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 250 C / cm 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, it was washed with water.

(D) The aluminum plate is etched by spraying with an aqueous solution having a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 35 ° C., the aluminum plate is dissolved by 0.2 g / m ^2, and the previous AC is used. In addition, the smut component mainly composed of aluminum hydroxide generated during electrochemical surface roughening was removed, and the edge portion of the generated pit was dissolved to smooth the edge portion. Thereafter, it was washed with water.

(E) A desmut treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(F) Anodization was performed for 50 seconds in an aqueous solution having a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions) at a temperature of 33 ° C. and a current density of 5 (A / dm ² ). Thereafter, it was washed with water. At this time, the weight of the anodized film was 2.7 g / m ² .
The surface roughness Ra of the aluminum support thus obtained was 0.27 (measuring instrument: Surfcom manufactured by Tokyo Seimitsu Co., Ltd., stylus tip diameter 2 micrometer).

<Undercoat layer>
Next, the following undercoat layer coating solution was applied to the aluminum support with a wire bar and dried at 90 ° C. for 30 seconds. The coating amount was 10 mg / m ² .

(Coating solution for undercoat layer)
-Polymer compound A having the following structure: 0.05 g
・ Methanol 27g
・ Ion exchange water 3g

(Photosensitive layer)
Next, the following photosensitive layer coating solution [P-1] was prepared and applied to the support using a wire bar. Drying was performed at 115 ° C. for 34 seconds using a warm air dryer. The photosensitive layer coverage after drying was 1.4 g / m ² .

<Photosensitive layer coating solution [P-1]>
・ Infrared absorber (IR-1) 0.120 g
-Polymerization initiator (OS-12) 0.55g
・ Additive (PM-1) 0.250g
-Polymerizable compound (AM-1) 1.33 g
-Binder polymer (BT-1) 1.00g
-Binder polymer (BT-2) 1.00 g
・ Ethyl violet (C-1) 0.07g
・ Fluorine-based surfactant 0.025g
(Megafuck F-780-F Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 18.4g
・ Methanol 9.83g
1-methoxy-2-propanol 18.4g

  The polymerization initiator (OS-12) used in the photosensitive layer coating solution refers to those exemplified as the onium salt compound examples represented by the general formula (1). Of infrared absorber (IR-1), additive (PM-1), polymerizable compound (AM-1), binder polymer (BT-1), ethyl violet (C-1) and binder polymer (BT-2) The structure is shown below.

(Protective layer)
On the surface of the photosensitive layer, synthetic mica (Somasif ME-100, 8% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (Goselan CKS-50: saponification degree 99 mol%, polymerization degree 300, sulfonic acid modification) A mixed aqueous solution (coating solution for protective layer) of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and a surfactant (manufactured by Nippon Emulsion Co., Ltd., Emalex 710) is applied with a wire bar, and 125 ° C. with a hot air dryer. For 75 seconds.
The content ratio of synthetic mica (solid content) / polyvinyl alcohol / surfactant in this mixed aqueous solution (protective layer coating solution) is 16/82/2 (mass%), and the coating amount is (after drying) coverage) was 1.6 g / m ^2.
As a result, a planographic printing plate precursor of Example 1 was obtained.

[Examples 2 to 5]
The lithographic printing plate precursors of Examples 2 to 5 were the same as Example 1 except that the blending amounts of BT-1 and BT-2 were changed as shown in Table 1 below in the photosensitive layer coating solution of Example 1. Got.
[Examples 6 to 8]
The lithographic printing plate precursors of Examples 6 to 8 were the same as Example 1 except that BT-2 was changed to BT-3, BT-4, and BT-5, respectively, in the photosensitive layer coating solution of Example 1. Got.

[Comparative Example 1]
The lithographic printing plate precursor of Comparative Example 1 was prepared in the same manner as in Example 1 except that BT-2 was added in the photosensitive layer coating solution of Example 1 and 2.0 g was added. Got.
[Comparative Example 2]
In Comparative Example 1, a lithographic printing plate precursor of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that the protective layer was not provided.
[Comparative Example 3]
A lithographic printing plate precursor of Comparative Example 3 was obtained in the same manner as in Example 1 except that the protective layer was not provided in Example 1.

[Comparative Examples 4 to 7]
In the photosensitive layer coating solution of Comparative Example 1, BT-1 was changed to BT-2, BT-3, BT-4, and BT-5, respectively. A lithographic printing plate precursor was obtained.

[Evaluation]
(1) Sensitivity evaluation The obtained lithographic printing plate precursor was laminated in a state where no interleaving paper was sandwiched, set on an Amiz setter manufactured by NEC, and automatically conveyed one by one. Exposure was performed while changing the log E by 0.15 in the range of 0 to 19 W output. The exposure was performed under conditions of 25 ° C. and 50% RH. After exposure, heat treatment and pre-water washing treatment before alkali development were not performed, and development processing was performed at a conveyance speed (line speed) of 2 m / min and a development temperature of 30 ° C. using an automatic developing machine LP-1310News manufactured by FUJIFILM Corporation. . The developer is a 1: 4 water diluted solution of DH-N manufactured by Fuji Film Co., Ltd., the developer replenisher is a 1: 1.4 water diluted solution of FCT-421 manufactured by FUJIFILM Corporation, and the finisher is Fuji. A 1: 1 water dilution of GN-2K manufactured by Film Co., Ltd. was used.
The cyan density of the image area density of the lithographic printing plate obtained by development was measured using a Macbeth reflection densitometer RD-918 and using a red filter equipped in the densitometer. The reciprocal of the exposure necessary to obtain a measured density of 0.9 was used as an index of sensitivity. The sensitivity of the lithographic printing plate obtained in Example 1 was set to 100, and the sensitivity of other lithographic printing plates was set as a relative evaluation. The larger the value, the higher the sensitivity. The results are shown in Table 1.

(2) Evaluation of printing durability The obtained lithographic printing plate was printed using a printing press Lithlon manufactured by Komori Corporation. The number of printed sheets was used as an index of printing durability. The results are shown in Table 1.
(3) Observation of missing photosensitive layer The planographic printing plate precursors (40 × 60 cm) of Examples and Comparative Examples were allowed to stand at 60 ° C. and 10% RH for 2 days, and the presence or absence of missing photosensitive layer was visually confirmed. The results are shown in Table 1.

(4) Evaluation of adhesion resistance between lithographic printing plate precursors Three lithographic printing plate precursors (10 × 10 cm) of Examples and Comparative Examples were conditioned for 2 hours in an environment of 25 ° C. and 75% RH, and then 3 Were sequentially stacked in a state without interleaving of the interleaving paper to obtain a laminate. The laminate was hermetically packaged with Al kraft paper and left standing at 30 ° C. for 5 days under a load of 4 kg. Thereafter, the adhesion state between the photosensitive layer side surface (protective layer surface) of the lithographic printing plate precursor and the back surface of the adjacent lithographic printing plate precursor was evaluated. Evaluation of adhesion resistance was performed by sensory evaluation. The results are shown in Table 1. ○ indicates a practical level, and × indicates an unusable level.

As is clear from Table 1, it was found that the lithographic printing plate precursors of Examples 1 to 8 were good in sensitivity and printing durability and did not cause the photosensitive layer to come off. In addition, the lithographic printing plate precursors of Examples 1 to 8 do not adhere even when they are laminated one after another in a state where no interleaving paper is sandwiched, so that plate making without using interleaving paper is possible within a practical range. It became possible, and the productivity in the plate making process was very high.
On the other hand, in the planographic printing plate precursor of Comparative Example 1 having only BT-1, both the sensitivity and the image forming property were good, but the photosensitive layer was missing. Further, the lithographic printing plate precursors of Comparative Example 2 and Comparative Example 3 that do not have a protective layer do not cause removal of the photosensitive layer, but are not satisfactory in sensitivity and printing durability, and have poor adhesion resistance. It could not be used without inserting the interleaving paper.
Further, in the planographic printing plate precursors of Comparative Examples 4 to 7 not containing BT-1, the photosensitive layer was not detached, but the sensitivity and the printing durability were not satisfactory.

Claims (6)

In a negative planographic printing plate precursor having a photosensitive layer containing a polymerization initiator, a polymerizable compound and a binder polymer and a protective layer in this order on a substrate, the photosensitive layer is represented by at least the following general formula (I) A negative lithographic printing plate precursor comprising a first binder polymer having a repeating unit and an acrylic second binder polymer having at least (meth) acrylic acid as a repeating unit.

(In general formula (I), R ¹ represents a hydrogen atom or a methyl group, and R ² is composed of two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom. And represents a linking group having 2 to 82 atoms, A represents an oxygen atom or —NR ³ —, and R ³ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Represents an integer of 1 to 5.)   The negative lithographic printing plate precursor according to claim 1, wherein the protective layer contains an inorganic stratiform compound.   The negative lithographic printing plate precursor as claimed in claim 1 or 2, wherein the photosensitive layer contains an infrared absorber.   The negative lithographic plate according to any one of claims 1 to 3, wherein the first binder polymer and / or the second binder polymer has a repeating unit having a radical polymerizable group in a side chain. A printing plate master.   The radically polymerizable group of the first binder polymer is at least one selected from the group consisting of a (meth) acryl group, an allyl group, and a styryl group. The negative lithographic printing plate precursor as described in Item 1.   The radically polymerizable group of the second binder polymer is at least one selected from the group consisting of a (meth) acryl group, an allyl group, and a styryl group. Negative type lithographic printing plate precursor.