JP5238176B2 - Negative-type planographic printing plate precursor and planographic printing method using the same - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor and a lithographic printing method using the same. Specifically, based on a digital signal from a computer or the like, for example, a negative lithographic printing plate precursor capable of direct plate making that can be directly made by scanning a laser having a wavelength of 300 to 1200 nm, and a development processing step The present invention relates to a lithographic printing method in which the lithographic printing plate precursor is directly developed and printed on a printing machine without going through the process.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, the lithographic printing plate precursor is exposed through an original image such as a lithographic film, and then the portion that becomes the image portion of the image recording layer is left, and the other unnecessary image recording layer is made alkaline solution or organic The lithographic printing plate is obtained by carrying out plate making by a method of exposing the surface of the hydrophilic support by dissolving and removing with a solvent.

  In the conventional plate making process of a lithographic printing plate precursor, a step of dissolving and removing an unnecessary image recording layer with a developer or the like corresponding to the image recording layer is necessary after the exposure. One of the problems is to make wet processing unnecessary or simplified. In particular, in recent years, disposal of waste liquids discharged with wet processing has become a major concern for the entire industry due to consideration for the global environment, and therefore, the demand for solving the above-mentioned problems has become stronger.

On the other hand, as one simple plate making method, an image recording layer that can remove an unnecessary portion of the image recording layer in a normal printing process is used. A method called on-press development has been proposed in which unnecessary portions are removed to obtain a lithographic printing plate.
As a specific method of on-press development, for example, a method of using a lithographic printing plate precursor having an image recording layer that can be dissolved or dispersed in an fountain solution, an ink solvent, or an emulsion of a fountain solution and an ink. , A method of mechanically removing the image recording layer by contact with rollers or a blanket cylinder of a printing press, cohesion force of the image recording layer by penetration of dampening water, ink solvent, etc., or between the image recording layer and the support. There is a method in which after the adhesive force is weakened, the image recording layer is mechanically removed by contact with rollers or a blanket cylinder.
In the present invention, unless otherwise specified, the “development process step” refers to using a device other than a printing press (usually an automatic developing machine) and bringing a liquid (usually an alkaline developer) into contact therewith. Refers to the step of removing the unexposed portion of the image recording layer from the laser and exposing the surface of the hydrophilic support, and “on-press development” refers to a liquid (usually printing ink and / or wet) using a printing press. This refers to a method and a process for removing the laser unexposed portion of the image recording layer and exposing the hydrophilic support surface by contacting with water.

On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate (CTP) technology has been attracting attention. Therefore, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.
As described above, in recent years, simplification, drying, and no processing of plate making operations have become more desirable than ever in terms of both consideration for the global environment and adaptation to digitalization. It is coming.

Among the lithographic printing plate precursors, the lithographic printing plate precursor capable of scanning exposure is an oleophilic photosensitive resin containing a photosensitive compound capable of generating active species such as radicals and Bronsted acids on a hydrophilic support by laser exposure. Tiers have been proposed and are already on the market. This lithographic printing plate precursor is laser-scanned based on digital information to generate active species, which causes physical or chemical changes in the photosensitive layer to insolubilize it, followed by development processing, thereby developing a negative lithographic printing plate Can be obtained. In particular, a photopolymerization type photosensitive layer containing a photopolymerization initiator excellent in photosensitive speed on a hydrophilic support, an ethylenically unsaturated compound capable of addition polymerization, and a binder polymer soluble in an alkali developer, and necessary A lithographic printing plate precursor provided with an oxygen-blocking protective layer in accordance with the printing plate having desirable printing performance from the advantages that it is excellent in productivity, is easy to develop, and has good resolution and inking properties. It can be.
Further, as an on-press developable lithographic printing plate precursor, for example, in Patent Document 1, an image forming layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder is provided on a hydrophilic support. The planographic printing plate precursor is described. In this Patent Document 1, the above lithographic printing plate precursor is exposed by an infrared laser, and the hydrophobic thermoplastic polymer particles are coalesced by heat to form an image, which is then mounted on a cylinder of a printing press and moistened. It is described that it is possible to perform on-press development with water and / or ink.
Such a method of forming an image by merging by simple thermal fusion of fine particles exhibits good on-press developability, but the image strength (adhesion with the support) is extremely weak and the printing durability is insufficient. Had the problem of being.

Patent Documents 2 and 3 describe lithographic printing plate precursors having an image recording layer (thermosensitive layer) containing microcapsules encapsulating a polymerizable compound on a hydrophilic support.
Patent Document 4 describes a lithographic printing plate precursor in which an image recording layer (photosensitive layer) containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound is provided on a support.
The method using such a polymerization reaction has a feature that the image strength is relatively good because the chemical bond density of the image portion is higher than that of the image portion formed by thermal fusion of polymer fine particles. From a general point of view, all of the on-press developability, fine line reproducibility and printing durability were still insufficient, and particularly when UV ink was used, printing durability was extremely insufficient.

Further, in Patent Document 5, on-press development is possible in which an image recording layer containing a polymerizable compound and a graft polymer having a polyethylene oxide chain in the side chain or a block polymer having a polyethylene oxide block is provided on a support. A planographic printing plate precursor is described.
However, this technology has good on-press developability, but fine line reproducibility and printing durability are still insufficient.
Japanese Patent No. 2938397 JP 2001-277740 A JP 2001-277742 A JP 2002-287334 A US Patent Application Publication No. 2003/0064318

  Accordingly, an object of the present invention is to provide a negative lithographic printing plate precursor capable of image recording by laser exposure. Another object of the present invention is to provide a negative lithographic printing plate precursor capable of on-press development without performing a development processing step, and a lithographic printing method. Furthermore, an object of the present invention is to provide a negative lithographic printing plate precursor which has excellent chemical resistance and has a large printing durability even when printing using UV ink (ultraviolet curable ink) is performed.

式中、Ｒ ^１ は水素原子又は置換基を有してもよい１価の有機基を表す。

式中、Ｒは水素原子又はメチル基を表し、ａは１、３又は５であり、ｌは１〜９の整数を表す。
〔２〕
前記一般式（Ｉ）のＲ ^１ が置換基を有してもよいアリール基であることを特徴とする上記〔１〕記載のネガ型平版印刷版原版。
〔３〕
前記一般式（Ｉ）で示される構造が、下記構造から選択されることを特徴とする上記〔１〕又は〔２〕に記載のネガ型平版印刷版原版。

〔４〕
前記一般式（ＩＩ）で表されるアルキレンオキサイド構造を有するラジカル重合性モノマーが、ポリオキシエチレンモノメタクリレート、ポリオキシエチレンモノアクリレート、ポリオキシプロピレンモノメタクリレート、又は、ポリオキシプロピレンモノアクリレートである、上記〔１〕〜〔３〕のいずれか１項に記載のネガ型平版印刷版原版。
〔５〕
前記光重合層が、更に赤外線吸収剤を含有することを特徴とする上記〔１〕〜〔４〕のいずれか１項に記載のネガ型平版印刷版原版。
〔６〕
前記光重合層中に含有される前記高分子化合物と前記重合性モノマーの質量比が、１／１〜１／３であることを特徴とする上記〔１〕〜〔５〕のいずれか一項に記載のネガ型平版印刷版原版。
〔７〕
前記光重合層が、マイクロカプセル又はミクロゲル含有することを特徴する上記〔１〕〜〔６〕のいずれか一項に記載のネガ型平版印刷版原版。
〔８〕
前記光重合層が印刷インキ及び／又は湿し水により除去可能であることを特徴とする上記〔１〕〜〔７〕のいずれか一項に記載のネガ型平版印刷版原版。
〔９〕
前記印刷インキがＵＶインキであることを特徴とする上記〔８〕に記載のネガ型平版印刷版原版。
〔１０〕
上記〔８〕に記載のネガ型平版印刷版原版を、レーザーで画像様に露光した後、印刷機に装着し、該平版印刷版原版に油性インキと水性成分とを供給して、光重合層の未露光部分を除去し、印刷する平版印刷方法。
〔１１〕
上記〔９〕に記載のネガ型平版印刷版原版を、レーザーで画像様に露光した後、印刷機に装着し、該平版印刷版原版にＵＶインキと水性成分とを供給して、光重合層の未露光部分を除去し、印刷する平版印刷方法。
本発明は、上記〔１〕〜〔１１〕に係る発明であるが、以下、参考のため、他の事項も含めて記載している。 As a result of studying various polymer compounds, the present inventors have found that the above object can be achieved by using a polymer compound having a plurality of specific functional groups in the photopolymerization layer, and have reached the present invention. The present invention is as follows.
[1]
A negative lithographic printing plate precursor having a photopolymerization layer containing a polymer compound, a polymerization initiator, and a polymerizable monomer obtained by copolymerization of maleimide and a radically polymerizable monomer having a hydrophilic group on a support. The maleimide-derived cyclic structure of the polymer compound is a structure represented by the following general formula (I), and the hydrophilic group is an alkylene oxide structure represented by the following general formula (II). Characteristic negative lithographic printing plate precursor.

In the formula, R ¹ represents a hydrogen atom or a monovalent organic group which may have a substituent.

In the formula, R represents a hydrogen atom or a methyl group, a is 1, 3 or 5, and 1 represents an integer of 1 to 9.
[2]
The negative lithographic printing plate precursor as described in [1] above, wherein R ^{1 in the} general formula (I) is an aryl group which may have a substituent.
[3]
The negative lithographic printing plate precursor as described in [1] or [2] above, wherein the structure represented by the general formula (I) is selected from the following structures:

[4]
The radical polymerizable monomer having an alkylene oxide structure represented by the general formula (II) is polyoxyethylene monomethacrylate, polyoxyethylene monoacrylate, polyoxypropylene monomethacrylate, or polyoxypropylene monoacrylate, The negative lithographic printing plate precursor as described in any one of [1] to [3].
[5]
The negative lithographic printing plate precursor as described in any one of [1] to [4] above, wherein the photopolymerization layer further contains an infrared absorber.
[6]
Any one of the above [1] to [5], wherein a mass ratio of the polymer compound and the polymerizable monomer contained in the photopolymerization layer is 1/1 to 1/3. Negative-type planographic printing plate precursor as described in 1.
[7]
The negative lithographic printing plate precursor as described in any one of [1] to [6] above, wherein the photopolymerization layer contains microcapsules or microgels.
[8]
The negative lithographic printing plate precursor as described in any one of [1] to [7] above, wherein the photopolymerizable layer can be removed with printing ink and / or fountain solution.
[9]
The negative lithographic printing plate precursor as described in [8] above, wherein the printing ink is UV ink.
[10]
The negative lithographic printing plate precursor as described in [8] above is imagewise exposed with a laser and then mounted on a printing machine, and an oil-based ink and an aqueous component are supplied to the lithographic printing plate precursor to form a photopolymerization layer A lithographic printing method in which the unexposed portion of the ink is removed and printed.
[11]
The negative lithographic printing plate precursor as described in [9] above is imagewise exposed with a laser and then mounted on a printing machine, and UV ink and an aqueous component are supplied to the lithographic printing plate precursor to form a photopolymerization layer. A lithographic printing method in which the unexposed portion of the ink is removed and printed.
The present invention is an invention according to the above [1] to [11], but is described below including other matters for reference.

(1) A negative lithographic printing plate precursor comprising a photopolymerization layer containing a polymer compound having a maleimide-derived cyclic structure and a hydrophilic group in the molecule on a support.
(2) The negative lithographic printing plate precursor as described in 1 above, wherein the cyclic structure derived from maleimide is a structure represented by the following general formula (I).

In the formula, R ¹ represents a hydrogen atom or a monovalent organic group which may have a substituent.

(3) The negative lithographic printing plate precursor as described in (2) above, wherein R ^{1 in the} general formula (I) is an aryl group which may have a substituent.
(4) The negative lithographic printing plate precursor as described in any one of (1) to (3) above, wherein the hydrophilic group has an alkylene oxide structure represented by the following general formula (II).

  In the formula, R represents a hydrogen atom or a methyl group, a is 1, 3 or 5, and 1 represents an integer of 1 to 9.

(5) The negative lithographic printing plate precursor as described in any one of (1) to (4) above, wherein the photopolymerization layer contains an infrared absorber, a polymerization initiator, and a polymerizable monomer.
(6) The negative lithographic printing plate precursor as described in any one of (1) to (5) above, wherein the photopolymerizable layer contains a microcapsule or a microgel.
(7) The mass ratio between the polymer compound having a cyclic structure derived from maleimide and a hydrophilic group contained in the photopolymerizable layer and a hydrophilic group in the molecule and a polymerizable monomer is from 1/1 to 1/3. The lithographic printing plate precursor as described in any one of 1 to 6 above.
(8) The negative lithographic printing plate precursor as described in any one of (1) to (7) above, wherein the photopolymerizable layer can be removed with printing ink and / or fountain solution.
(9) The negative lithographic printing plate precursor as described in any one of (1) to (8) above, wherein the photopolymerizable layer can be removed with UV ink and / or fountain solution.
(10) The negative lithographic printing plate precursor as described in 8 above is mounted on a printing machine and imagewise exposed with a laser, or after imagewise exposure with a laser and mounted on a printing machine, and the lithographic plate A lithographic printing method in which an oil-based ink and an aqueous component are supplied to a printing plate precursor to remove an unexposed portion of the photopolymerization layer and print.
(11) The negative lithographic printing plate precursor as described in 9 above is mounted on a printing press and imagewise exposed with a laser, or after imagewise exposure with a laser and then mounted on a printing press. A lithographic printing method in which UV ink and an aqueous component are supplied to a printing plate precursor to remove an unexposed portion of the photopolymerization layer and print.

  In the present invention, the use of a polymer compound having a maleimide-derived cyclic structure and a hydrophilic group in the molecule can achieve the solution to the above problem. The mechanism of action is not clear, but by having a maleimide-derived cyclic structure, (1) the high polarity of the structure and (2) the interaction between the compounds impedes the penetration of chemicals and UV inks. It is possible that Further, it is presumed that by having a hydrophilic group in the molecule, the fountain solution quickly penetrates into the photopolymerization layer, and quick on-press developability can be obtained.

  According to the present invention, the on-press developability is excellent, the fine line reproducibility and the printing durability are good, and even when printing using UV ink is performed, a large number of good printed matter can be obtained, and the printing durability. Can be provided, and a lithographic printing method using the same.

[Negative lithographic printing plate precursor]
The negative planographic printing plate precursor of the present invention is premised on having a laser-sensitive photopolymerization layer on a hydrophilic support. Hereinafter, the photopolymerization layer and other components will be described in detail.

<Photopolymerization layer>
[Polymer compound having maleimide-derived cyclic structure and hydrophilic group in the molecule]
The photopolymerization layer of the present invention contains, as a binder polymer, a polymer compound having a maleimide-derived cyclic structure and a hydrophilic group in the molecule (hereinafter, appropriately referred to as a specific polymer compound) as essential components. By containing this specific polymer compound, chemical resistance and improvement in printing durability in printing using UV ink and good on-press developability can be obtained.

  The cyclic structure derived from maleimide of the present invention is a structural unit derived from unsubstituted maleimide or a maleimide having various substituents on the nitrogen atom, and particularly a structure represented by the following general formula (I). preferable.

In formula (I), R ¹ represents a hydrogen atom or a monovalent organic group which may have a substituent, and from the viewpoint of improving chemical resistance, R ¹ may be a monovalent which may have a substituent. The organic group is preferably. As the monovalent organic group suitably used, an alkyl group having 1 to 12 carbon atoms and an aryl group having 6 to 14 carbon atoms are preferable, and an aryl group is more preferable from the viewpoint of improving chemical resistance. The group is particularly preferred.
Substituents that can be introduced into the organic group include hydroxyl group, carboxyl group, sulfonamide group, active imide group and other alkali-soluble acid groups, amide groups, cyano groups, nitro groups, carboxylic acid ester groups, sulfonic acid esters A hydrogen atom capable of hydrogen bonding such as a group, an acyl group, a polar substituent having a hetero atom, a hydrocarbon group such as an alkyl group or an aryl group, and a heterocyclic group having an atom such as nitrogen, oxygen or sulfur in the ring Can be mentioned. As a substituent for the aryl group, a hydroxyl group or a sulfonamide group is preferable.

  Examples of maleimide-derived cyclic structures that can be suitably used for the specific polymer compound of the present invention include the following, but the present invention is not limited thereto.

  As for the cyclic structure derived from maleimide, only one type may be used in the specific polymer compound according to the present invention, or two or more types may be included. These maleimide-derived cyclic structures are preferably contained in the specific polymer compound in the range of 10 to 80 mol%, more preferably in the range of 30 to 70 mol%, from the viewpoints of printing durability and chemical resistance. .

  In the present invention, from the viewpoint of on-press developability, the molecule has a hydrophilic group. Examples of such hydrophilic groups include hydroxyl group, carboxyl group, carboxylate group, hydroxyethyl group, alkylene oxide structure, hydroxypropyl group, polyoxyethyl group, polyoxypropyl group, amino group, aminoethyl group, There are aminopropyl group, ammonium group, amide group, carboxymethyl group, sulfonic acid group, phosphoric acid group and the like, and preferred are amide group, hydroxyl group, polyoxyethyl group, and the following general formula (II) The alkylene oxide structure represented is most preferred.

  In formula (II), R represents a hydrogen atom or a methyl group, a is 1, 3 or 5, and 1 represents an integer of 1 to 9. l is preferably an integer of 1 to 8, more preferably an integer of 1 to 7, still more preferably an integer of 1 to 6, and most preferably an integer of 1 to 4.

  The specific polymer compound of the present invention is obtained by copolymerizing maleimide, which is a precursor of the cyclic structure, with the radical polymerizable monomer having the hydrophilic group in a suitable solvent using a known polymerization initiator. Can be obtained.

  Specific examples of the radical polymerizable compound having such a hydrophilic group and a polymerizable unsaturated bond include acrylamide, methacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, N-vinylpyrrolidone, N-vinyl. Examples include acetamide, N-acryloylmorpholine, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, polyoxyethylene monomethacrylate, polyoxyethylene monoacrylate, polyoxypropylene monomethacrylate, and polyoxypropylene monoacrylate. These may be used alone or in combination of two or more in the specific polymer compound of the present invention. The suitable content of the monomer unit having a hydrophilic group in the specific polymer compound is 1 to 85 mol%, particularly preferably 5 to 70 mol%.

  The specific polymer compound of the present invention is for the purpose of improving various performances such as image strength, and in addition to the above-mentioned radical polymerizable compound having a substituent, as long as the effects of the present invention are not impaired. It is also a preferred embodiment to copolymerize the active compound. Examples of the radical polymerizable compound that can be copolymerized with the specific polymer compound in the present invention include acrylic acid esters, methacrylic acid esters, N, N-2 substituted acrylamides, and N, N-2 substituted methacrylamides. Radical polymerizable compounds selected from styrene, styrenes, acrylonitriles, methacrylonitriles, and the like.

  Specifically, for example, acrylic esters such as alkyl acrylate (the alkyl group preferably has 1 to 20 carbon atoms) (specifically, for example, methyl acrylate, ethyl acrylate, acrylic Propyl butyl, butyl acrylate, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate , Pentaerynuritol monoacrylate, glycidyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.), aryl acrylate (e.g., phenyl Methacrylic acid esters (eg, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl). Methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, Glycidyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate Styrene) such as methyl methacrylate, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl, aryl methacrylate (for example, phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate, etc.), styrene, alkyl styrene, etc. Styrene, hexyl styrene, cyclohexyl styrene, decyl styrene, benzyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, etc.), alkoxy styrene (for example, methoxy styrene, 4-methoxy-3-methyl styrene, dimethoxy) Styrene), halogen styrene (e.g. chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlors) Styrene, pentachlorostyrene, prom styrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene, etc.), acrylonitrile, Examples include methacrylonitrile.

  The specific polymer compound of the present invention may have an ester group represented by the following formula (III) or an amide group represented by the following formula (IV) in the molecule.

  In formula, b is an integer of 2-5, c is an integer of 2-7, m and n represent the integer of 1-100 each independently.

  Of these radical polymerizable compounds, acrylic acid esters, methacrylic acid esters, and styrenes are preferably used. These can be used singly or in combination of two or more. The content of these copolymerization components is preferably 0 to 95 mol%, particularly preferably 20 to 90 mol%.

  The specific copolymer of the present invention may be any of a block copolymer, a random copolymer, and a graft copolymer.

  Examples of the solvent used for synthesizing such a polymer compound include ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, propanol, butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxy. Examples include ethyl acetate, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, toluene, ethyl acetate, methyl lactate, and ethyl lactate. It is done. These solvents may be used alone or in combination of two or more.

  The specific polymer compound according to the present invention has a mass average molecular weight Mw, preferably 2,000 or more, and more preferably 5,000 to 300,000. Moreover, the specific polymer compound according to the present invention may contain an unreacted monomer. In this case, the proportion of the monomer in the polymer compound is desirably 15% by mass or less.

  The content of the specific polymer compound contained in the photopolymerization layer of the present invention is preferably about 5 to 95% by mass, more preferably about 10 to 85% by mass in terms of solid content. Within this range, good image area strength and image formability can be obtained.

  Although the specific example of the structural unit of the specific polymer compound used as a binder polymer in this invention is shown below, it is not limited to these.

[Other binder polymers]
In the present invention, conventionally known binder polymers can be used without limitation in addition to the specific polymer compound, and among these, linear organic polymers having film properties are preferred. Examples of such binder polymers include acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, and synthetic rubbers. And natural rubber.

  The binder polymer preferably has crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.

Examples of the polymer having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid, where the ester or amide residue (R of -COOR or CONHR) is ethylene. Examples thereof include polymers having a polymerizable unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{^{bond, - (CH 2) n CR}} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ¹ ═CR ² R ³ and (CH ₂ CH ₂ O) ₂ —X (wherein R ^{1 to} R ³ are each a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms, an aryl group, and an alkoxy group. R ¹ and R ² or R ³ may be bonded to each other to form a ring, n represents an integer of 1 to 10. X represents a dicyclopentadienyl residue. Represents a group).

Specific examples of the ester residue include —CH ₂ CH═CH ₂ (described in JP-B-7-21633), —CH ₂ CH ₂ O—CH ₂ CH═CH ₂ , —CH ₂ C. _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ —OCO—CH═CH _2. Is mentioned.

  The binder polymer having crosslinkability, for example, has a free radical (polymerization initiation radical or a growth radical in the polymerization process of the polymerizable monomer) added to the crosslinkable functional group, and the polymerization chain of the polymerizable monomer is directly formed between the polymers. Through addition polymerization, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded together, thereby causing cross-linking between polymer molecules. Forms and cures.

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0, per 1 g of the binder polymer. -7.0 mmol, most preferably 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

From the viewpoint of improving the on-press developability, the binder polymer preferably has high solubility or dispersibility in ink and / or fountain solution.
In order to improve solubility or dispersibility in ink, the binder polymer is preferably oleophilic, and in order to improve solubility or dispersibility in dampening water, the binder polymer is hydrophilic. Is preferred. For this reason, in the present invention, it is also effective to use a lipophilic binder polymer and a hydrophilic binder polymer in combination.

  Examples of the hydrophilic binder polymer include hydroxyl group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, and ammonium. Preferred examples include those having a hydrophilic group such as a group, an amide group, a carboxymethyl group, a sulfo group, or a phosphoric acid group.

  Specific examples include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, Polymethacrylic acids and their salts, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and copolymers, hydroxybutyl methacrylate homopolymers Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate, polyethylene glycol Alcohols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more, methacryl Homopolymers and polymers of amides, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyethers of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. It is done.

  The binder polymer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. More preferred. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.

  The binder polymer may be either a random polymer or a block polymer, but is preferably a random polymer. Moreover, a binder polymer may be used independently or may be used in mixture of 2 or more types.

The binder polymer can be obtained by purchasing a commercial product or synthesizing it by a conventionally known method. Solvents used in the synthesis include, for example, tetrahydrofuran, ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy. Examples include 2-propanol, 1-methoxy-2-propyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, toluene, ethyl acetate, methyl lactate, ethyl lactate, dimethyl sulfoxide, and water. These may be used alone or in combination of two or more.
As the radical polymerization initiator used for synthesizing the binder polymer, known compounds such as an azo initiator and a peroxide initiator can be used.

  Content of a binder polymer is 0-90 mass% with respect to the total solid of a photopolymerization layer, It is preferable that it is 0-80 mass%, and it is more preferable that it is 0-70 mass%. Within this range, good image area strength and image formability can be obtained.

[Infrared absorber]
When forming an image of the lithographic printing plate precursor according to the invention with a laser light source that emits infrared rays of 760 to 1200 nm, for example, it is preferable to contain an infrared absorber in the photopolymerization layer. The infrared absorber has a function of converting absorbed infrared rays into heat. Due to the heat generated at this time, a polymerization initiator (radical generator) described later is thermally decomposed to generate radicals. Examples of the infrared absorber used in the present invention include dyes or pigments having an absorption maximum at a wavelength of 760 to 1200 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.
Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, The methine dyes described in JP-A-58-181690 and JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, Naphthoquinone dyes described in JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, and the like, squarylium dyes described in JP-A-58-112792, and the like; And cyanine dyes described in British Patent No. 434,875.

In addition, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also suitable. ) Pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59- No. 41363, No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and Pyrlium compounds described in JP-A-59-216146. And pentamethine thiopyrylium salts described in US Pat. No. 4,283,475, and Japanese Patent Publication Nos. 5-13514 and 5-19702. Pyrylium compounds shown also preferably used.
Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).
Other preferable examples of the infrared absorbing dye of the present invention include specific indolenine cyanine dyes described in JP-A-2002-278057 as exemplified below.

  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 preferable, and one particularly preferable example is a cyanine dye represented by the following general formula (i).

In formula (i), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group shown below.

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 a carbon atom having 1 to 12 carbon atoms including a hetero atom. Indicates a hydrogen group. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.
X a ^_- is Z _a which will be described below ^- has the same definition as, 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 in the general formula (i) each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Z _a ^- represents a counter anion. However, when the cyanine dye represented by the general formula (i) has an anionic substituent in its structure and neutralization of charge is not necessary, Z _a ⁻ is not necessary. Preferred Z _a ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion and a sulfonate ion, particularly preferably a perchlorate ion, from the storage stability of the recording layer coating solution. Hexafluorophosphate ion and aryl sulfonate ion.

Specific examples of cyanine dyes represented by formula (i) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. Can do.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, 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.

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

  The particle 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 this range, good stability of the pigment dispersion in the photopolymerization layer coating solution and good uniformity of the photopolymerization layer can be obtained.

  As a method for dispersing the pigment, a known dispersion technique used for 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).

These infrared absorbers may be added to the same layer as other components, or may be added to another layer, but photopolymerization is performed when a negative lithographic printing plate precursor is prepared. The layer is added so that the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm is in the range of 0.3 to 1.2 by the reflection measurement method. Preferably, it is the range of 0.4-1.1. Within this range, a uniform polymerization reaction proceeds in the depth direction of the photopolymerization layer, and good film strength of the image area and adhesion to the support can be obtained.
The light absorbency of a photopolymerization layer can be adjusted with the quantity of the infrared absorber added to a photopolymerization layer, and the thickness of a photopolymerization layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, a photopolymerization layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is determined as the optical density. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

(Polymerization initiator)
A polymerization initiator can be used in the photopolymerization layer of the present invention. The polymerization initiator used is a compound that generates radicals by the energy of light, heat, or both, and initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group. Various polymerization initiators known in the literature or the like, or a combination system (polymerization initiation system) of two or more polymerization initiators can be appropriately selected and used.

  Examples of radical generating compounds include organic halides, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boric acid compounds, disulfone compounds, and oxime esters. Compounds and onium salt compounds.

  Specific examples of the organic halide include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Examined Patent Publication No. 46-4605, JP 48-36281, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62-58241, JP 62 -212401, JP-A-63-70243, JP-A-63-298339, M.S. P. Hut "Journal of Heterocyclic Chemistry" 1 (No3), (1970) "The compound described in a brush is mentioned, Especially the oxazole compound substituted by the trihalomethyl group: S-triazine compound is mentioned.

  More preferably, an s-triazine derivative having at least one mono, di, or trihalogen-substituted methyl group bonded to the s-triazine ring, specifically, for example, 2,4,6-tris (monochloromethyl)- s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methyl-4,6-bis (trichloromethyl)- s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, -(3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1 -(P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- ( p-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-isopropyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-tolyl) ) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-natoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-pheni Thio-4,6-bis (trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris (tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) -S-triazine and the like.

  Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylpheny ) Acetophenone derivatives such as ketones, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, p And benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.
Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4 ′ − Tra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate), carbonyl And di (t-hexylperoxydihydrogen diphthalate).

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, Di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di- -Cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-penta Fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoropheny -1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4 , 5,6-pentafluorophen-1-yl, iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109, and the like.

  Examples of the hexaarylbiimidazole compound include, for example, Japanese Patent Publication No. 6-29285, U.S. Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. And, specifically, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) )) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2 ′ -Bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (m-methoxyphenyl) biidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4', 5,5 '-Tetraphenylbi Midazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5 Examples include 5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and the like.

  Examples of the organic borate compounds include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, and JP-A-9-188710. 2000-131837, Japanese Patent Application Laid-Open No. 2002-107916, Japanese Patent No. 2764769, Japanese Patent Application Laid-Open No. 2002-116539, and Kunz, Martin “Rad Tech'98. Proceeding April 19-22, 1998, Chicago. Organic borate salts or organic boron oxosulfonium complexes described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, JP-A-6-175554, JP-A-6-17 Organoboron iodonium complexes described in JP-A No. 553, organoboron phosphonium complexes described in JP-A-9-188710, JP-A 6-348011, JP-A 7-128785, JP-A 7-140589, Specific examples include organoboron transition metal coordination complexes such as JP-A-7-306527 and JP-A-7-292014.

Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.
Examples of the oxime ester compounds include JCS Perkin II (1979) 1653-1660), JCS
Perkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, compounds described in JP 2000-66385 A, compounds described in JP 2000-80068 A, specifically, Examples include compounds represented by the structural formula.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055 and 4,069,056, phosphonium salts described in European Patent Nos. 104 and 143, U.S. Pat. Nos. 339,049 and 410,201, 2-150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297,442 U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013, 4,73 No. 4,444, No. 2,833,827, German Patent Nos. 2,904,626, 3,604,580, and 3,604,581

J. et al. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

In particular, from the viewpoint of reactivity and stability, the above oxime ester compounds, diazonium salts, iodonium salts, sulfonium salts, and ammonium salts are exemplified. In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
The onium salts suitably used in the present invention are onium salts represented by the following general formulas (RI-I) to (RI-IV).

In the formula (RI-I), Ar ¹¹ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and 1 to 1 carbon atoms. 12 alkenyl groups, C 1-12 alkynyl groups, C 1-12 aryl groups, C 1-12 alkoxy groups, C 1-12 aryloxy groups, halogen atoms, C 1-12 carbon atoms Alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, C1-C12 thioalkyl group, carbon The thioaryl group of number 1-12 is mentioned. Z ^11- represents a monovalent anion, which is a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, Perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, and sulfinate ion are preferable from the viewpoint of the visibility of the printout image.

In formula (RI-II), Ar ²¹ and Ar ²² each independently represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents are alkyl having 1 to 12 carbon atoms. Group, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, a halogen atom, C1-C12 alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, C1-C1 Examples include 12 thioalkyl groups and thioaryl groups having 1 to 12 carbon atoms. Z ^21- represents a monovalent anion, which is a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, From the surface, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable.

In formula (RI-III), R ³¹ , R ³² and R ³³ each independently represents an aryl group having 20 or less carbon atoms, an alkyl group, an alkenyl group or an alkynyl group, which may have 1 to 6 substituents. From the viewpoint of reactivity and stability, an aryl group is preferable. Preferred substituents are alkyl groups having 1 to 12 carbon atoms, alkenyl groups having 1 to 12 carbon atoms, alkynyl groups having 1 to 12 carbon atoms, aryl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms. Z ^31- represents a monovalent anion, which is a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, Perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferred from the standpoint of printout image visibility, and more preferred are those described in JP-A-2001-343742. Carboxylic acid ions, particularly preferably those described in JP-A No. 2002-148790.

In formula (RI-IV), R ⁴¹ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent. R ⁴² , R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ each independently represents an aryl group having 20 or less carbon atoms, an alkyl group, an alkenyl group, or an alkynyl group, which may have 1 to 6 substituents, From the viewpoint of reactivity and stability, an aryl group is desirable. Preferred substituents are alkyl groups having 1 to 12 carbon atoms, alkenyl groups having 1 to 12 carbon atoms, alkynyl groups having 1 to 12 carbon atoms, aryl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms. R ⁴¹ and R ⁴³ , R ⁴² and R ⁴³ , R ⁴³ and R ⁴⁴ , R ⁴⁴ and R ⁴⁵ , and R ⁴⁵ and R ⁴⁶ may be connected to each other to form a ring. Z ^31- represents a monovalent anion, which is a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, Perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferred from the standpoint of printout image visibility.
Examples of onium salts that can be suitably used as a polymerization initiator in the present invention will be given below, but the present invention is not limited thereto.

Among these polymerization initiators, from the viewpoint of improving the printed image visibility, an onium salt having an inorganic anion such as PF ₆ ⁻ or BF ₄ ⁻ as a counter ion is preferable. Furthermore, diaryliodonium and ammonium are preferable as onium because of excellent printing durability.

  These polymerization initiators are added in a proportion of 0.1 to 50% by mass, preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total solid content constituting the photopolymerization layer. Can do. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

(Polymerizable monomer)
The photopolymerizable layer of the present invention preferably contains a polymerizable monomer in order to perform an efficient curing reaction. The polymerizable monomer that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is a compound having at least one terminal ethylenically unsaturated bond, preferably two or more. To be elected. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is 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 Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. 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, isocyanuric acid There are EO-modified triacrylate and the like.

  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, for example, aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, and JP-A-59-5241. And those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613. 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.

  Further, urethane-based addition polymerizable compounds produced using an addition reaction of isocyanate and hydroxyl group are also suitable. Specific examples of such compounds are described in, for example, Japanese Patent Publication No. 48-41708. It contains 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 (ii) to a polyisocyanate compound having two or more isocyanate groups in the molecule. A vinyl urethane compound etc. are mentioned.

^{_{CH 2 = C (R 4)}} COOCH 2 CH (R 5) OH (ii)
(However, R ⁴ and R ⁵ represent H or CH _3. )

  Further, urethane acrylates as described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 And urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418. Furthermore, 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 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and acrylic acid or methacrylic acid described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-B-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, specific unsaturated compounds described in each gazette, vinylphosphonic acid compounds described in JP-A-2-25493, and the like are also included. Can 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 monomers, the details of usage, such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
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. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable, and furthermore, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrene compound, vinyl ether type A method of adjusting both sensitivity and strength by using a compound) is also effective. Further, the selection and use method of the addition polymerization compound is also an important factor for the compatibility and dispersibility with other components in the photopolymerization layer (for example, binder polymer, initiator, colorant, etc.). In some cases, the compatibility can be improved by using a low-purity compound or by using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving the adhesion of the substrate and the protective layer described later.

The polymerizable monomer is preferably used in the range of 5 to 80% by mass, and more preferably 25 to 75% by mass with respect to the nonvolatile component in the photopolymerization layer. These may be used alone or in combination of two or more. In addition, the usage of the polymerizable monomer can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer construction and coating method such as undercoating and overcoating can also be carried out.
The polymerizable monomer and the binder polymer are preferably used in an amount of 0.5 / 1 to 4/1 in terms of mass ratio, more preferably 1/1 to 3/1, and more preferably 1.5 / 1 to 2. Most preferably, it is 5/1.

[Microcapsule / Microgel]
In the present invention, several modes can be used as a method for causing the photopolymerization layer to contain the above-described photopolymerization layer constituent components and other components described later. One is a molecular dispersion type photopolymerization layer in which the constituent components are dissolved and applied in an appropriate solvent as described in, for example, JP-A-2002-287334. In another embodiment, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or a part of the constituent components are encapsulated in microcapsules and contained in the photopolymerization layer. It is a microcapsule type photopolymerization layer. Further, in the microcapsule type photopolymerization layer, the constituent component can be contained outside the microcapsule. Here, it is preferable that the microcapsule type photopolymerization layer includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule. Still another embodiment includes an embodiment in which the photopolymerization layer contains crosslinked resin particles, that is, microgel. The microgel may contain a part of the constituent component in and / or on the surface thereof. In particular, an embodiment in which a reactive microgel is formed by having a polymerizable monomer on the surface thereof is particularly preferable from the viewpoint of image formation sensitivity and printing durability.
In order for the photopolymerization layer to be removable by printing ink and / or dampening water, that is, a photopolymerization layer that can be developed on-press, it is preferable to contain microcapsules or microgels.

A known method can be applied as a method for microencapsulating or microgelling the constituent components of the polymerization layer.
For example, as a method for producing microcapsules, US Pat. No. 2,800,547, US Pat. No. 2,800,498, a method using coacervation, US Pat. No. 3,287,154, Japanese Patent Publication No. 38-19574, The method by the interfacial polymerization method found in US Pat. No. 42-446, the method by the precipitation of polymer found in US Pat. Nos. 3,418,250 and 3,660,304, the isocyanate found in US Pat. No. 3,796,669 Method using polyol wall material, method using isocyanate wall material found in US Pat. No. 3,914,511, urea found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802 -Formaldehyde or urea formaldehyde A method using a resorcinol-based wall forming material, a method using a wall material such as melamine-formaldehyde resin, hydroxycellulose, etc. found in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method by monomer polymerization, spraying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling seen in British Patent Nos. 952807 and 967074 There are laws, but it is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Further, a compound having a crosslinkable functional group such as an ethylenically unsaturated bond capable of introducing a binder polymer may be introduced into the microcapsule wall.

On the other hand, as a method for preparing the microgel, granulation by interfacial polymerization described in JP-B-38-19574 and JP-A-42-446, non-patent document as described in JP-A-5-61214, and the like. Granulation by aqueous dispersion polymerization can be used. However, it is not limited to these methods.
As the method using the interfacial polymerization, the known microcapsule production method described above can be applied.

  Preferred microgels used in the present invention are those granulated by interfacial polymerization and having three-dimensional crosslinking. From such a viewpoint, the material to be used is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and polyurea and polyurethane are particularly preferable.

  The average particle size of the microcapsules or microgel is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

[Surfactant]
In the present invention, it is preferable to use a surfactant in the photopolymerization layer in order to promote on-press developability at the start of printing and to improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

  The anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.
The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Moreover, the fluorine-type surfactant described in each gazette of Unexamined-Japanese-Patent No. 62-170950, 62-226143, and 60-168144 is also mentioned suitably.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 7% by mass with respect to the total solid content of the photopolymerization layer.

[Colorant]
In the present invention, various compounds other than these may be added as necessary. For example, a dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc., and JP-A-62-2 And dyes described in No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The addition amount is 0.01 to 10% by mass with respect to the total solid content of the image recording material.

[Bake-out agent]
In the photopolymerization layer of the present invention, a compound that is discolored by an acid or a radical can be added in order to generate a printout image. As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

  Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Kogyo Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethylphosphoric triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (Ciba Geigy).

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by an acid or a radical is 0.01 to 10% by mass with respect to the solid content of the photopolymerization layer.

(Polymerization inhibitor)
A small amount of a thermal polymerization inhibitor is preferably added to the photopolymerization layer of the present invention in order to prevent unnecessary thermal polymerization of the (C) radical polymerizable monomer during the production or storage of the photopolymerization layer.
Examples of the thermal polymerization inhibitor 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-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the photopolymerization layer.

[Higher fatty acid derivatives, etc.]
In order to prevent polymerization inhibition due to oxygen, a higher fatty acid derivative such as behenic acid or behenamide is added to the photopolymerization layer of the present invention, and the surface of the photopolymerization layer is dried during the coating process. It may be unevenly distributed. The amount of the higher fatty acid derivative added is preferably about 0.1 to about 10% by mass with respect to the total solid content of the photopolymerization layer.

[Plasticizer]
The photopolymerizable layer of the present invention may contain a plasticizer in order to improve on-press developability.
Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in.
The plasticizer content is preferably about 30% by mass or less based on the total solid content of the photopolymerization layer.

[Inorganic fine particles]
The photopolymerizable layer of the present invention may contain inorganic fine particles in order to improve the strength of the cured film in the image area and to improve the on-press developability of the non-image area.
As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, or a mixture thereof is preferably exemplified. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like.
The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that is stably dispersed in the photopolymerization layer, sufficiently retains the film strength of the photopolymerization layer, and hardly causes stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the photopolymerization layer.

[Low molecular hydrophilic compounds]
The photopolymerizable layer of the present invention may contain a hydrophilic low molecular compound for improving on-press developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Examples thereof include organic carboxylic acids such as salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid and amino acids, and salts thereof.

(Formation of photopolymerization layer)
The photopolymerization layer of the present invention is formed by dispersing or dissolving the necessary components of the photosensitive composition in a solvent to prepare a coating solution, and coating and drying on a support. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, water and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The photopolymerization layer of the present invention can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeating a plurality of coatings and dryings.

Moreover, although the application amount (solid content) of the photopolymerization layer on the support obtained after application | coating and drying changes with uses, generally 0.3-3.0 g / m < ² > is preferable. Within this range, good sensitivity and good film properties of the photopolymerization layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Support>
The support used for the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like material. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. A preferable support includes a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. 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 preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and still more preferably 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it becomes easy to improve hydrophilicity and secure adhesion between the photopolymerization layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used and cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / ^{m 2,} and more preferably 1.5 to 4.0 g / ^{m 2.} Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  After the anodizing treatment, the surface of the aluminum plate is subjected to a hydrophilic treatment as necessary. The hydrophilization treatment is described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in each specification of No.272.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the photopolymerization layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

<Back coat layer>
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Of these, the use of silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ is inexpensive. It is preferable in that it is easily available.

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, an undercoat layer can be provided between the photopolymerizable layer and the support, if necessary. In the case of an on-press development type lithographic printing plate precursor, there is an advantage that on-press developability is improved because the undercoat layer tends to cause peeling of the photopolymerizable layer from the support in the unexposed area. In addition, in the case of infrared laser exposure, since the undercoat layer functions as a heat insulating layer, the heat generated by the exposure does not diffuse to the support and can be used efficiently, so that the sensitivity can be increased. There is.
Specific examples of the undercoat layer compound (undercoat compound) include silane coupling agents having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, Preferable examples include phosphorus compounds having an ethylenic double bond reactive group described in Kaihei 2-304441.
The most preferable undercoat compound includes a polymer resin obtained by copolymerizing a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group.

An essential component of the undercoat polymer resin is an adsorptive group on the hydrophilic support surface. The presence or absence of adsorptivity on the surface of the hydrophilic support can be determined by the following method, for example.
A coating night is prepared by dissolving the test compound in a readily soluble solvent, and the coating night is coated and dried on the support so that the coating amount after drying is 30 mg / m ² . Next, the support coated with the test compound is sufficiently washed with a readily soluble solvent, and then the residual amount of the test compound that has not been removed by washing is measured to calculate the adsorbed amount of the support. Here, the measurement of the remaining amount may be performed by directly quantifying the amount of the remaining compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. The compound can be quantified by, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, liquid chromatography measurement and the like. The compound having support adsorptivity is a compound that remains at 1 mg / m ² or more even after the above-described washing treatment.

The adsorptive group on the surface of the hydrophilic support is a substance (for example, metal, metal oxide) or a functional group (for example, hydroxyl group) existing on the surface of the hydrophilic support and a chemical bond (for example, ionic bond, hydrogen). Bond, coordination bond, bond by intermolecular force). The adsorptive group is preferably an acid group or a cationic group.
The acid group preferably has an acid dissociation constant (pKa) of 7 or less. Examples of the acid group include a phenolic hydroxyl group, a carboxyl _{group, -SO 3 H, -OSO 3 H} , -PO 3 H 2, -OPO 3 H 2, -CONHSO 2 -, - SO 2 NHSO 2 - and COCH ₂ COCH ₃ is included. Of these, OPO ₃ H ₂ and PO ₃ H ₂ are particularly preferable. These acid groups may be metal salts.
The cationic group is preferably an onium group. Examples of the onium group include an ammonium group, a phosphonium group, an arsonium group, a stibonium group, an oxonium group, a sulfonium group, a selenonium group, a stannonium group, and an iodonium group. An ammonium group, a phosphonium group and a sulfonium group are preferred, an ammonium group and a phosphonium group are more preferred, and an ammonium group is most preferred.

  Particularly preferred examples of the monomer having an adsorptive group include compounds represented by the following formula (iii) or (iv).

In the above formula, R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms. R ¹ , R ² and R ³ are each independently preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferred is a hydrogen atom or a methyl group. R ² and R ³ are particularly preferably a hydrogen atom. Z is a functional group that adsorbs to the surface of the hydrophilic support.
In the formula (iii), X is an oxygen atom (—O—) or imino (—NH—). X is more preferably an oxygen atom. In the formula (iii), L is a divalent linking group. L is a divalent aliphatic group (alkylene group, substituted alkylene group, alkenylene group, substituted alkenylene group, alkynylene group, substituted alkynylene group), divalent aromatic group (arylene group, substituted arylene group) or divalent Or an oxygen atom (—O—), a sulfur atom (—S—), an imino (—NH—), a substituted imino (—NR—, where R is an aliphatic group, an aromatic group. Or a heterocyclic group) or a combination with carbonyl (—CO—).

The aliphatic group may have a cyclic structure or a branched structure. The number of carbon atoms in the aliphatic group is preferably 1 to 20, more preferably 1 to 15, and most preferably 1 to 10. The aliphatic group is preferably a saturated aliphatic group rather than an unsaturated aliphatic group. The aliphatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aromatic group, and a heterocyclic group.
The number of carbon atoms in the aromatic group is preferably 6 to 20, more preferably 6 to 15, and most preferably 6 to 10. The aromatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aliphatic group, an aromatic group, and a heterocyclic group.
The heterocyclic group preferably has a 5-membered or 6-membered ring as the heterocycle. Another heterocyclic ring, an aliphatic ring or an aromatic ring may be condensed with the heterocyclic ring. The heterocyclic group may have a substituent. Examples of substituents include halogen atoms, hydroxyl groups, oxo groups (═O), thioxo groups (═S), imino groups (═NH), substituted imino groups (═N—R, R is an aliphatic group, aromatic Group or heterocyclic group), aliphatic group, aromatic group and heterocyclic group.

L is preferably a divalent linking group containing a plurality of polyoxyalkylene structures. The polyoxyalkylene structure is more preferably a polyoxyethylene structure. In other words, L preferably contains — (OCH ₂ CH ₂ ) _n — (n is an integer of 2 or more).
In the formula (iv), Y is a carbon atom or a nitrogen atom. When Y is a nitrogen atom and L is connected to Y to form a quaternary pyridinium group, Z itself is adsorbable, so Z is not essential, and Z may be a hydrogen atom. L represents the same divalent linking group or single bond as in formula (iii).

The adsorptive functional group is as described above.
Examples of typical compounds represented by formula (iii) or (iv) are shown below.

  Examples of the hydrophilic group of the undercoat polymer resin that can be used in the present invention include a hydroxyl group, a carboxyl group, a carboxylate group, a hydroxyethyl group, a polyoxyethyl group, a hydroxypropyl group, a polyoxypropyl group, and an amino group. Preferred examples include a group, aminoethyl group, aminopropyl group, ammonium group, amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group. Among these, a monomer having a sulfo group exhibiting high hydrophilicity is preferable. Specific examples of the monomer having a sulfo group include methallyloxybenzenesulfonic acid, allyloxybenzenesulfonic acid, allylsulfonic acid, vinylsulfonic acid, p-styrenesulfonic acid, methallylsulfonic acid, acrylamide t-butylsulfonic acid, Examples include 2-acrylamido-2-methylpropanesulfonic acid, (3-acryloyloxypropyl) butylsulfonic acid sodium salt, and amine salt. Of these, 2-acrylamido-2-methylpropanesulfonic acid sodium salt is preferred in view of hydrophilic performance and handling of synthesis.

  The polymer resin for the undercoat layer of the present invention preferably has a crosslinkable group. The crosslinkable group can improve the adhesion with the image area. In order to make the polymer resin for the undercoat layer crosslinkable, a crosslinkable functional group such as an ethylenically unsaturated bond is introduced into the side chain of the polymer, or the polar substituent of the polymer resin is countercharged. Or a compound having an ethylenically unsaturated bond may be introduced by forming a salt structure.

  Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid, where the ester or amide residue (R of -COOR or CONHR) is ethylene. Examples thereof include polymers having a polymerizable unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO -CR ₁ = _CR 2 _{R 3,} and _(CH 2 CH ₂ O) in ₂ -X _(wherein, R 1 to R ₃ are each a hydrogen atom, a halogen atom or an alkyl group having 1 to 20 carbon atoms, an aryl group, Represents an alkoxy group or an aryloxy group, and R ₁ and R ₂ or R ₃ may combine with each other to form a ring, n represents an integer of 1 to 10. X represents dicyclopentadienyl. Represents a residue).
Specific examples of the ester residue include —CH ₂ CH═CH ₂ (described in JP-B-7-21633), —CH ₂ CH ₂ O—CH ₂ CH═CH ₂ , —CH ₂ C. _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 NHCOO-CH 2 CH = CH 2, and CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ O—Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ OCO—CH═CH _2. Is mentioned.
As the monomer having a crosslinkable group of the polymer resin for the undercoat layer, an ester or amide of acrylic acid or methacrylic acid having the crosslinkable group is preferable.

  The content of the crosslinkable group in the polymer resin for the undercoat layer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol per 1 g of the polymer resin. Preferably it is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol. Within this range, both good sensitivity and dirtiness and good storage stability can be obtained.

The polymer resin for the undercoat layer preferably has a mass average molecular weight of 5000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1000 or more, preferably 2000 to 25 More preferably, it is 10,000. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The polymer resin for the undercoat layer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

The undercoat polymer resin may be used alone or in combination of two or more. The undercoat layer coating solution is obtained by dissolving the above-described undercoat polymer in an organic solvent (for example, methanol, ethanol, acetone, methyl ethyl ketone, etc.) and / or water. The undercoat layer coating solution may contain an infrared absorber.
Various known methods can be used as a method of applying the undercoat layer coating solution to the support. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / ^{m 2,} and more preferably 1 to 30 mg / ^{m 2.}

<Protective layer>
The lithographic printing plate precursor according to the present invention is protected on the photopolymerization layer as necessary to impart oxygen barrier properties, prevent scratches in the photopolymerization layer, prevent ablation that occurs during high-illuminance laser exposure, and the like. A layer (overcoat layer) can be provided.
Usually, the exposure processing of a lithographic printing plate is carried out in the atmosphere. The image formation reaction in the photopolymerization layer caused by the exposure process can be inhibited by low molecular compounds such as oxygen and basic substances present in the atmosphere. The protective layer prevents low molecular compounds such as oxygen and basic substances from entering the photopolymerization layer, and as a result, suppresses image formation inhibition reaction in the air. Therefore, the property desired for the protective layer is to reduce the permeability of low molecular compounds such as oxygen, and furthermore, the transparency of light used for exposure is good, and the adhesiveness with the photopolymerization layer is excellent. And it can be easily removed in an on-press development process after exposure. The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

  As a material used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used. Specifically, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, polyacrylic acid, polyacrylamide, partially saponified product of polyvinyl acetate, ethylene-vinyl alcohol copolymer, water-soluble cellulose derivative, gelatin, starch Examples thereof include water-soluble polymers such as derivatives and gum arabic, and polymers such as polyvinylidene chloride, poly (meth) acrylonitrile, polysulfone, polyvinyl chloride, polyethylene, polycarbonate, polystyrene, polyamide, and cellophane. These may be used in combination of two or more as required.

  A relatively useful material among the above materials includes water-soluble polymer compounds having excellent crystallinity. Specifically, water-soluble acrylic resins such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, and polyacrylic acid, gelatin, gum arabic, and the like are suitable. Among these, water can be applied as a solvent, and at the time of printing Polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl imidazole are preferable from the viewpoint that they are easily removed by the fountain solution. Among them, polyvinyl alcohol (PVA) gives the best results for basic properties such as oxygen barrier properties and development removability.

  The polyvinyl alcohol that can be used in the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains a substantial amount of an unsubstituted vinyl alcohol unit having the required water solubility. Similarly, a part may contain other copolymerization components. For example, various hydrophilic modification sites such as anion modification sites modified with anions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the anion-modified site, the cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol and various organic acids. Polyvinyl alcohol having various degrees of polymerization having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, etc. at the polymer chain end is also preferably used.

  Suitable examples of these modified polyvinyl alcohols include compounds having a hydrolysis degree of 71 to 100 mol% and a polymerization degree in the range of 300 to 2400. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, 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 modified polyvinyl alcohol include KL-318, KL-118, KM-618, KM-118, SK-5102 having an anion-modified site, C-318, C-118, and CM-318 having a cation-modified site. M-205 and M-115 having terminal thiol modification sites, MP-103, MP-203, MP-102 and MP-202 having terminal sulfide modification sites, and ester modification sites with higher fatty acids HL-12E, HL-1203, and other reactive silane-modified R-1130, R-2105, R-2130, and the like.

The protective layer preferably contains a layered compound. The layered compound is a particle having a thin plate-like shape. For example, the following general formula A (B, C) 2-5D ₄ O ₁₀ (OH, F, O) ₂
[However, A is any of Li, K, Na, Ca, Mg, organic cation, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.
Examples of the natural mica include muscovite, soda mica, phlogopite, biotite and sericite. Further, as the synthetic mica, 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-based Na or Li hectorite (Na, Li) 1/8 Mg _{2 / 5Li 1/8 (Si 4} O 10) swelling mica _{F 2.} Synthetic smectite is also useful.

Among the above layered compounds, fluorine-based swellable mica which is a synthetic layered compound is particularly useful. That is, swellable clay minerals such as mica, montmorillonite, saponite, hectorite and bentonite have a laminated structure composed of unit crystal lattice layers with a thickness of 10 to 15 mm, and the substitution of metal atoms in the lattice has other viscosity. It is significantly larger than minerals. As a result, the lattice layer has a shortage of positive charges, and in order to compensate for this, organic cations such as Li ⁺ , Na ⁺ , Ca ²⁺ , Mg ²⁺ , amine salts, quaternary ammonium salts, phosphonium salts and sulfonium salts are provided between the layers. Adsorbs cations. These layered compounds swell with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swelling synthetic mica have this tendency.

As the shape of the layered compound, from the viewpoint of diffusion control, the thinner the better, the better the planar size 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, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.
The average particle diameter of the layered compound is 1 to 20 μm, preferably 1 to 10 μm, particularly preferably 2 to 5 μm. When the particle diameter is smaller than 1 μm, the suppression of permeation of oxygen and moisture is insufficient and the effect cannot be exhibited sufficiently. On the other hand, if it is larger than 20 μm, the dispersion stability in the coating solution is insufficient, resulting in a problem that stable coating cannot be performed. 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. For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is 1 to 50 nm in thickness and 1 to 20 μm in surface size.

When the inorganic layered compound particles having such a large aspect ratio are contained in the protective layer, the coating film strength is improved, and the permeation of oxygen and moisture can be effectively prevented. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.
It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by mass ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of types of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

  When the inorganic layered compound is used for the protective layer, it is preferable to add a phosphonium compound to the photopolymerization layer and / or the protective layer in order to improve the inking property. The phosphonium compound is preferably a phosphonium compound represented by the following general formula (v) or (vi). Especially, the phosphonium compound represented by general formula (v) is preferable.

In formula (v), Ar _{1 to} Ar ₆ each independently represents an aryl group or a heterocyclic group, L represents a divalent linking group, X represents an n-valent counter anion, and n represents 1 to 1 3 represents an integer, and m represents a number satisfying n × m = 2. Here, as the aryl group, phenyl group, naphthyl group, tolyl group, xylyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, methoxyphenyl group, ethoxyphenyl group, dimethoxyphenyl group, methoxycarbonylphenyl group, dimethylaminophenyl A group and the like are preferable. Examples of the heterocyclic group include a pyridyl group, a quinolyl group, a pyrimidinyl group, a thienyl group, and a furyl group.

  L represents a divalent linking group. 6-15 are preferable and, as for carbon number in a coupling group, More preferably, it is a C6-C12 coupling group.

X ⁻ represents a counter anion, and preferred examples include halogen anions such as Cl ⁻ , Br ⁻ and I ⁻ , sulfonate anions, carboxylate anions, sulfate ester anions, PF 6 ⁻ , BF 4 ⁻ and perchlorate anions. Can be mentioned. Of these, halogen anions such as Cl ⁻ , Br ⁻ and I ⁻ , sulfonate anions, and carboxylate anions are particularly preferable.

  Specific examples of the phosphonium salt represented by the general formula (v) used in the present invention are shown below.

In the general formula (vi), R _{1 to} R ₄ are each independently an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, alkoxy group, aryl group, aryloxy group, which may have a substituent, Represents an alkylthio group, a heterocyclic group or a hydrogen atom; At least two of R _{1 to} R ₄ may be bonded to form a ring. X ⁻ represents a counter anion.
Here, when R _{1 to} R ₄ are an alkyl group, an alkoxy group or an alkylthio group, the carbon number is usually 1 to 20, and when R _{1 to} R ₄ is an alkenyl group or an alkynyl group, the carbon number is usually 2 to 15 and a cycloalkyl group. In some cases, the number of carbon atoms is usually 3 to 8, the aryl group is a phenyl group, a naphthyl group, etc., the aryloxy group is a phenoxy group, a naphthyloxy group, etc., the arylthio group is a phenylthio group, etc. Examples of the group include a furyl group and a thienyl group. Examples of the substituent that may be present include, for example, alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, alkoxy groups, alkoxycarbonyl groups, acyl groups, alkylthio groups, aryl groups, aryloxy groups, arylthio groups. Group, sulfino group, sulfo group, phosphino group, phosphoryl group, amino group, nitro group, cyano group, hydroxyl group, halogen atom and the like. These substituents may further have a substituent.
Examples of the anion represented by X ⁻ include halide ions such as Cl ⁻ , Br ⁻ and I ⁻ , inorganic acid anions such as ClO ₄ ⁻ , PF ₆ ⁻ and SO ₄ ⁻² , organic carboxylate anions and organic sulfonate anions. Can be mentioned. Examples of the organic group of the organic carboxylate anion and organic sulfonate anion include methyl, ethyl, propyl, butyl, phenyl, methoxyphenyl, naphthyl, fluorophenyl, difluorophenyl, pentafluorophenyl, thienyl, pyrrolyl and the like. Among these, Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ ⁻ , PF ₆ ^{− and the} like are preferable. Specific examples of phosphonium compounds suitable for the present invention are shown below.

  As addition amount of the phosphonium salt to a photopolymerization layer or a protective layer, 0.01-20 mass% is preferable in solid content of each layer, 0.05-10 mass% is more preferable, 0.1-5 mass% is 0.1-5 mass% Most preferred. Within these ranges, good ink fillability can be obtained.

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers can be added. These activators can be added in an amount of 0.1 to 100% by mass relative to the (co) polymer.

  In order to improve the adhesion to the image area, for example, JP-A-49-70702 and British Patent Application No. 1303578 disclose an acrylic polymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesion can be obtained by mixing 20 to 60% by mass of a water-based emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer, and the like, and laminating on a photopolymerization layer. Any of these known techniques can be used in the present invention.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (for example, a water-soluble dye) that is excellent in the transparency of infrared rays used for exposure and that can efficiently absorb light of other wavelengths, safe light is not caused. Suitability can be improved.

  Next, an example of a general dispersion method of the layered compound used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable laminar compound mentioned above as a preferred laminar compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen. 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. A dispersion of 5 to 10% by mass of the inorganic stratiform compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a protective layer coating solution using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder solution.

  This protective layer coating solution includes known anionic surfactants, nonionic surfactants, cationic surfactants, fluorosurfactants and water-soluble plasticizers for improving the physical properties of the coating. Additives can be added. 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, you may add to this coating liquid the well-known additive for improving the adhesiveness with a photopolymerization layer and the temporal stability of a coating liquid.

The protective layer coating solution thus prepared is applied on the photopolymerization layer provided on the support and dried to form the protective layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water. The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. . Specific examples of the protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.
The coating amount of the protective layer, the coating amount after drying is preferably in the range of 0.01 to 10 g / ^{m 2,} more preferably in the range of 0.02 to 3 g / ^{m 2,} and most preferably 0. in the range of 02~1g / ^{m 2.}

[Lithographic printing method]
As the light source for exposing the lithographic printing plate precursor according to the invention, a known light source can be used. Specifically, various lasers are preferably used as the light source. In the planographic printing method of the present invention, the planographic printing plate precursor is imagewise exposed with an infrared laser. The infrared laser used is not particularly limited, and a solid laser and a semiconductor laser that emit infrared rays having a wavelength of 760 to 1200 nm are preferable.
The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like. The output of the infrared laser is preferably 100 mW or more. In order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure time per pixel is preferably within 20 μs. Moreover, it is preferable that irradiation energy amount is 10-300 mJ / cm < ² >.

In the lithographic printing method of the present invention, after exposing the lithographic printing plate precursor of the present invention imagewise with an infrared laser as described above, oil-based ink and aqueous component are supplied without any development processing steps. Print.
Specifically, after exposing the lithographic printing plate precursor with an infrared laser, it is mounted on a printing machine without passing through a development process, and after printing the lithographic printing plate precursor on the printing machine, Examples of the method include printing with exposure using an infrared laser.

After the lithographic printing plate precursor is imagewise exposed with an infrared laser, the aqueous component and the oil-based ink are supplied and printed without going through a development processing step such as a wet development processing step. In this case, in the exposed portion of the photopolymerization layer, the photopolymerization layer cured by exposure forms an oil-based ink receiving portion having a lipophilic surface. On the other hand, in the unexposed area, the uncured photopolymerization layer is dissolved or dispersed and removed by the supplied aqueous component and / or oil-based ink, and a hydrophilic surface is exposed in the area. As a result, the aqueous component adheres to the exposed hydrophilic surface, and the oil-based ink is deposited on the photopolymerized layer in the exposed area, and printing is started.
Here, an aqueous component or oil-based ink may be first supplied to the plate surface. However, in the on-press development type lithographic printing plate precursor according to the present invention, the aqueous component is contaminated by the photopolymerized layer in the unexposed area. In order to prevent this, it is preferable to supply oil-based ink first. As the aqueous component and oil-based ink, dampening water and printing ink for ordinary lithographic printing are used.

  By using the lithographic printing plate precursor according to the present invention, even when UV ink is used, on-press development and subsequent printing can be performed in the same manner as in the lithographic printing method, and good printing durability can be obtained. As the UV ink, a commercially available ink can be usually used.

  In this way, the lithographic printing plate precursor is subjected to on-press development on an offset printing machine and used as it is for printing a large number of sheets.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to these. However, Example 4 is read as Reference Example 4.

[Examples 1 to 8 and Comparative Example 1]
1. Preparation of lithographic printing plate precursor (1) Preparation of support In order to remove rolling oil on the surface of an aluminum plate (material 1050) having a thickness of 0.3 mm, a 10 mass% sodium aluminate aqueous solution is used at 50 ° C for 30 seconds. After degreasing, the aluminum surface is grained using ^three bundled nylon brushes with a bristle diameter of 0.3 mm and a pumice-water suspension with a median diameter of 25 μm (specific gravity: 1.1 g / cm ³ ). Washed well with. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .
Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (containing 0.5% by mass aluminum ions), and the liquid temperature was 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Further, in a 0.5% by mass aqueous solution of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C., nitric acid electrolysis is performed under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode An electrochemical surface roughening treatment was performed in the same manner, followed by washing with water by spraying. The plate was provided with a direct current anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, then washed with water and dried. The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm. Furthermore, the following undercoat liquid (1) was applied so that the dry coating amount was 6 mg / m ² to obtain a support.

-Undercoat liquid (1)-
Undercoat compound (1) (mass average molecular weight: 60,000) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

(2) Formation of Photopolymerization Layer and Protective Layer A photopolymerization layer coating solution having the following composition was bar-coated on the support on which the undercoat layer had been formed, and then oven-dried at 100 ° C. for 60 seconds. A photopolymerization layer of 0 g / m ² was formed.
Subsequently, a protective layer coating solution having the following composition is bar-coated on the photopolymerization layer, and oven-dried at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.15 g / m ^2. (1) to (6) and a comparative lithographic printing plate precursor (R1) were obtained.
The photopolymerization layer coating solution was obtained by mixing and stirring the photosensitive solution shown in Table 1 and the microgel solution (1) below immediately before coating.
In the photosensitive solution (R1) used in Comparative Example 1, instead of the specific polymer compound of the present invention, a comparative specific polymer (R-1) having the following structure was used.

-Photosensitive solutions (1) to (9) and (R1)-
Binder polymer (Exemplary compounds of the present invention described in Table 1) 0.177 g
Infrared absorber (1) 0.031g
Polymerizable monomer (Aronix M-215 (manufactured by Toa Gosei Co., Ltd.)) 0.319 g
Polymerization initiator 0.213g
Phosphonium compound (1) 0.035 g
Fluorosurfactant (1) 0.004g
Anionic surfactant 0.125g
(Pionine A-24-EA (Takemoto Yushi Co., Ltd., 40% by mass aqueous solution)
Methyl ethyl ketone 2.554g
1-methoxy-2-propanol 7.023 g

-Microgel solution (1)-
Microgel liquid dispersion (1) 1.800 g
1.678 g of water

-Synthesis of microgel dispersion (1)-
As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (manufactured by Mitsui Takeda Chemical Co., Ltd., Takenate D-110N, 75% by mass ethyl acetate solution) 10.0 g, as a polymerizable monomer Aronix M-215 (Toa Synthesis Co., Ltd.) 6.00 g and Piionin A-41C (Takemoto Yushi Co., Ltd.) 0.12 g were dissolved in ethyl acetate 16.67 g. As an aqueous phase component, 37.5 g of a 4 mass% aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 2 hours. The microcapsule liquid thus obtained was diluted with distilled water to a solid content concentration of 21% by mass to obtain a microgel dispersion (1). The average particle size was 0.23 μm.

  The structure of each compound used in the photosensitive solution is shown below.

1.5 g of protective layer coating solution / inorganic layered compound dispersion (1) below
・ Polyvinyl alcohol 0.06g
(PVA105, manufactured by Kuraray Co., Ltd., saponification degree 98.5 mol%, polymerization degree 500)
・ Polyvinylpyrrolidone 0.01g
(Polyvinylpyrrolidone K30, manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight Mw = 40,000)
・ Vinyl pyrrolidone / vinyl acetate copolymer 0.01g
(LUVITEC VA64W, manufactured by ISP, copolymerization ratio = 6/4)

-Preparation of inorganic layered compound dispersion (1)-
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained layered compound dispersed particles was 100 or more.

2. Exposure, printing and evaluation of lithographic printing plate precursor Each lithographic printing plate precursor obtained in the above Examples and Comparative Examples was output by a Creo Trendsetter 3244VX equipped with a water-cooled 40 W infrared semiconductor laser, output 9 W, outer drum rotation speed 210 rpm, The exposure was performed under the condition of a resolution of 2400 dpi. The exposure image includes a thin line chart.

In general, in the case of a negative type lithographic printing plate precursor, when the exposure amount is small, the degree of cure of the photosensitive layer (photopolymerization layer in the present invention) becomes low, and when the amount of exposure is large, the degree of cure increases. If the photopolymerization layer has a too low degree of curing, the printing durability of the lithographic printing plate will be low, and the reproducibility of small dots and fine lines will be poor. On the other hand, when the degree of curing of the photopolymerization layer is high, the printing durability is increased, and the reproducibility of small dots and fine lines is improved.
In this example, as shown below, the negative lithographic printing plate precursor obtained as described above was evaluated for printing durability and fine line reproducibility under the same exposure amount conditions described above. It was used as an index of sensitivity. That is, it can be said that the sensitivity of the lithographic printing plate precursor is higher as the number of printed sheets in printing durability is higher and the fine line width in fine line reproducibility is thinner.

(1) On-press developability Without exposing the obtained exposed original plate to a cylinder of a printing machine SOR-M manufactured by Heidelberg, dampening water (EU-3 (Effect manufactured by Fuji Film Co., Ltd.)) / Water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), and after supplying dampening water and ink, Printing was performed at a printing speed of 6,000 sheets per hour. At this time, the number of print sheets (on-press developability) required until the ink was not transferred to the unexposed portion (non-image portion) of the photopolymerization layer was evaluated. The smaller the number, the better the on-press developability. The evaluation results are shown in Table 1.

(2) Fine line reproducibility As described above, after 100 sheets were printed and it was confirmed that a printed matter having no ink stains in the non-image area was obtained, 500 sheets were continuously printed. A thin line chart (10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 60, 80, 100, and 200 μm fine line exposed charts) of a total of 600 printed sheets with a 25X magnifier The fine line reproducibility was evaluated by observing and fine line width reproduced with ink without interruption. The evaluation results are shown in Table 1.

(3) Normal ink printing durability As described above, after printing was performed in the evaluation of fine line reproducibility, printing was further continued. As the number of printed sheets was increased, the photopolymerization layer was gradually worn out and the ink receptivity was lowered, so that the ink density in the printing paper was lowered. Printing durability was evaluated by the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing. The evaluation results are shown in Table 1.

(4) UV ink printing durability The obtained exposed original plate was attached to a cylinder of a Dia IF-2 printer manufactured by Mitsubishi Heavy Industries, Ltd. without developing. After supplying fountain solution and ink using IF102 2% aqueous solution of fountain solution (Fuji Film) and Best Cure UV-BF-WRO standard black ink (T & K TOKA), printing 10,000 sheets per hour Printing was performed at speed.
In the evaluation of printing durability, the number of sheets in which the image density of the obtained printed matter was reduced by 5% from the start of printing was judged to be finished. The evaluation results are shown in Table 1.

  From the results of Table 1, the negative lithographic printing plate precursor of the present invention containing a polymer compound having a maleimide-derived cyclic structure and a hydrophilic group in the molecule in the photopolymerization layer is usually used for ink printing durability and on-press development. It was confirmed that the UV ink printing durability was excellent as well as the properties.

Claims (11)

On a support, a maleimide and a polymer compound obtained by copolymerization of a radical polymerizable monomer having a hydrophilic group, the polymerization initiator and a polymerizable monomer having a photopolymerizable layer containing René gas lithographic printing In the plate precursor , the maleimide-derived cyclic structure of the polymer compound is a structure represented by the following general formula (I), and the hydrophilic group is an alkylene oxide structure represented by the following general formula (II): A negative lithographic printing plate precursor characterized by being .

In the formula, R ¹ represents a hydrogen atom or a monovalent organic group which may have a substituent.

In the formula, R represents a hydrogen atom or a methyl group, a is 1, 3 or 5, and 1 represents an integer of 1 to 9. Negative planographic printing plate precursor according to claim 1, wherein R ¹ is characterized in that it is a aryl group which may have a substituent in the general formula (I). The negative lithographic printing plate precursor as claimed in claim 1 or 2, wherein the structure represented by the general formula (I) is selected from the following structures.

  The radical polymerizable monomer having an alkylene oxide structure represented by the general formula (II) is polyoxyethylene monomethacrylate, polyoxyethylene monoacrylate, polyoxypropylene monomethacrylate, or polyoxypropylene monoacrylate. Item 4. The negative lithographic printing plate precursor according to any one of Items 1 to 3.   The negative lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the photopolymerization layer further contains an infrared absorber. The weight ratio of the polymerizable monomer and the polymer compound contained in the photopolymerizable layer is, according to any one of claims 1 to 5, characterized in that a 1 / 1-1 / 3 Negative type lithographic printing plate precursor. The negative lithographic printing plate precursor according to any one of claims 1 to 6 , wherein the photopolymerization layer contains a microcapsule or a microgel. The negative lithographic printing plate precursor according to any one of claims 1 to 7, wherein the photopolymerizable layer can be removed by printing ink and / or fountain solution. Negative planographic printing plate precursor according to claim 8, wherein the printing ink is a UV-in key. The negative planographic printing plate precursor according to claim 8, after the imagewise exposure in Les Za, mounted on a printing machine, by supplying oily ink and an aqueous component to the planographic printing plate precursor, the photopolymerizable layer A lithographic printing method in which the unexposed portion of the ink is removed and printed. The negative planographic printing plate precursor according to claim 9, after the imagewise exposure in Les Za, mounted on a printing machine, by supplying the UV ink and an aqueous component to the planographic printing plate precursor, the photopolymerizable layer A lithographic printing method in which the unexposed portion of the ink is removed and printed.