JP2007245662A - Lithographic printing form original plate and lithographic printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing form original plate, in which an image can be formed without alkaline development after an image-wise exposure with laser rays and all fine line reproducibility, plate wearability, hardness to stain and on-press developing properties are favorable, and a lithographic printing method. <P>SOLUTION: In the lithographic printing form original plate, in which the image can be formed without alkaline development under the condition that an undercoating layer and a laser ray sensitive polymer layer is provided on a hydrophilic support, the undercoating layer includes at least (a1) a repeating unit having an ethylenic unsaturated linkage, (a2) a repeating unit having a functional group interacting with the surface of the support and (a3) a repeating unit having a hydrophilic functional group and the polymeric compound is a graft polymer having a branch polymer including the unit (a1). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a negative lithographic printing plate precursor for CTP (computer to plate computer) and a lithographic printing method using the lithographic printing plate precursor.

  Conventionally, negative lithographic printing plate precursors (negative PS plates) are widely known and have various photosensitive layers (image recording layers). There are diazo resin-containing type, photopolymerization type, photocrosslinking type and the like. In order to prepare a lithographic printing plate from such a negative lithographic printing plate precursor, it is common to place a transparent negative film original (lithic film) on the lithographic printing plate precursor and expose the image using ultraviolet rays. Therefore, the work was very troublesome. In recent years, with the development of image forming technology, computer-to-plate technology has been developed, in which plate exposure is performed directly on a lithographic printing plate precursor without using a lithographic film by laser exposure based on digital data such as a computer. Sensitive laser recording lithographic printing plate precursors have been developed.

  In addition, in a conventional negative type lithographic printing plate precursor, after exposure, development with an alkaline developer, and further, the developed printing plate is washed with water, or treated with a rinse solution containing a surfactant. A post-treatment with the oil-based solution was also necessary. In the rationalization of the plate making process, simplification of these wet treatments together with CTP is also a big study subject. In order to simplify the process, development is possible with a near-neutral aqueous solution or simple water, and as a method of simplifying the process itself, an exposed lithographic printing plate precursor is mounted on the cylinder of a printing press. A method called on-machine development has been developed in which a photosensitive layer corresponding to a non-image area is removed by supplying dampening water and ink while rotating a cylinder.

  As a photosensitive layer for a lithographic printing plate precursor corresponding to such a laser recording system, the photopolymerization system is most suitable in that it is easy to cope with high sensitivity and simplification of processing. However, since the polymerization photosensitive layer does not necessarily have a strong adhesive force with the support, when it is used for printing a large number of copies at a high speed, a solid image may be lost, or fine lines and highlights may be thinned or skipped. Arise. Therefore, in high-sensitivity photopolymerization systems, photoadhesiveness between the support and the photosensitive layer is an important factor, and many researches and developments have been made.

For example, it is known to provide a layer containing a polymer having a polymerizable group having an ethylenically unsaturated bond and a phosphoric acid group between a polymerization type photosensitive layer and a support (see Patent Document 1). In addition, a technique is also known in which a functional group capable of causing an addition reaction due to a radical is provided on the support surface by a covalent bond so as to have an adhesive force with the photopolymerization type photosensitive layer (for example, Patent Documents 2 to 2). 4).
A photosensitive layer and a support comprising a compound obtained by hydrolyzing and dehydrating and condensing a silane coupling agent having an ethylenic double bond, and a compound containing an alkylene oxide chain and an acryloyl group or methacryloyl group in one molecule. It is also known to provide between (see Patent Document 5).

In addition, a technique for improving adhesion to a support by incorporating a phosphate ester compound having a (meth) acryloyl group into a photosensitive layer is also known (see Patent Document 6).
JP-A-2-304441 Japanese Patent Laid-Open No. 3-56177 Japanese Patent Laid-Open No. 7-159983 JP-A-8-320551 Japanese Patent Laid-Open No. 10-282679 Japanese Patent Laid-Open No. 11-30858

However, from the practical viewpoint, these conventional techniques are still insufficient in any of fine line reproducibility, printing durability, resistance to stains, and on-press developability, and further improvements have been desired.
The object of the present invention is to respond to this, and after image-wise exposure with a laser, an image can be formed without alkali development. Both are to provide a good planographic printing plate precursor and planographic printing method.

1. A lithographic printing plate precursor having an undercoat layer and a laser light-sensitive polymer layer on a hydrophilic support and capable of forming an image without alkali development, wherein at least (a1) an ethylenically unsaturated bond is formed on the undercoat layer And (a2) a polymer compound having a repeating unit having at least one functional group that interacts with the support surface and (a3) a repeating unit having at least one hydrophilic functional group. The lithographic printing plate precursor, wherein the polymer compound is (a1) a graft polymer having a branched polymer containing a repeating unit having at least one ethylenically unsaturated bond.
2. 2. The lithographic printing plate precursor as described in 1 above, wherein the polymerization layer contains an infrared absorber.
3. 3. The lithographic printing plate precursor as described in 1 or 2 above, wherein the polymerized layer contains microcapsules or microgels.
4). The lithographic printing plate precursor according to any one of 1 to 3 is mounted on a printing press and imagewise laser-exposed, or after imagewise exposure with a laser and mounted on a printing press, A lithographic printing method in which printing ink and fountain solution are supplied to a lithographic printing plate precursor to remove a laser unexposed portion of the polymerized layer and print.

The present inventor uses, as a polymer compound contained in the undercoat layer, (a1) a graft polymer in which a part containing a repeating unit having at least one ethylenically unsaturated bond is a branched polymer (graft chain). As a result, the above-mentioned problems have been achieved.
The mechanism of action is not necessarily clear, but by making the unit of (a1) a graft chain, the mobility of the polymerizable ethylenically unsaturated bond group is increased and the reactivity with the photosensitive layer is improved. As a result, the image portion and the support are selectively and closely adhered to each other, so that it is presumed that high printing durability was obtained without deteriorating the developability.

  According to the present invention, after imagewise exposure with a laser, an image can be formed without alkali development, and lithographic printing has excellent fine line reproducibility, printing durability, resistance to stains, and on-machine developability. Can provide plate precursor and lithographic printing methods.

I. Planographic printing plate precursor (undercoat layer)
In the present invention, the undercoat layer has at least (a1) a repeating unit having at least one ethylenically unsaturated bond, (a2) a repeating unit having at least one functional group that interacts with the support surface, and (a3) a hydrophilic property. A graft polymer having a branched polymer containing a repeating compound having a repeating unit having at least one ethylenically unsaturated bond, comprising a polymer compound having a repeating unit having at least one functional group (a1); (Hereinafter also referred to as “specific graft polymer”).

The specific graft polymer of the present invention can be generally produced using a method known as a method for synthesizing a graft polymer. Specifically, a general method for synthesizing a graft polymer is described in “Graft Polymerization and its Applications” by Fumio Ide, published in 1977, “Polymer Publishing”, and “New Polymer Experiments 2, Polymer Synthesis / Reaction "edited by Polymer Society of Japan, Kyoritsu Shuppan Co., Ltd. 1995, and these can be applied.
As a synthesis method of the graft polymer, basically, 1. 1. Polymerize the branch monomer from the trunk polymer. 2. Link the branch polymer to the trunk polymer. It can be divided into three methods of copolymerizing a branch polymer with a trunk polymer (macromer method). Of these three methods, the graft polymer of the present invention can be prepared by using any of these three methods, but “3. Macromer method” is particularly excellent from the viewpoint of production suitability and control of the film structure.
The synthesis of graft polymer using a macromonomer is described in the aforementioned “New Polymer Experiments 2, Polymer Synthesis / Reaction” edited by Polymer Society of Japan, Kyoritsu Publishing Co., Ltd. 1995. It is also described in detail in Yamashita Yu et al., “Macromonomer Chemistry and Industry”, IPC, 1989.

  The specific graft polymer of the present invention preferably contains a repeating unit represented by the following formula (I).

In formula (I), A ₁ represents a repeating unit containing at least one ethylenically unsaturated bond, A ₂ represents a repeating unit containing at least two functional groups that interact with the support surface, and A ₃ Represents a repeating unit containing at least one hydrophilic graft chain. x, y, z represents a copolymerization ratio, and x1 represents a graft chain length.

In the formula (I), the repeating unit represented by A ₁ is preferably represented by the following formula (A1).

In the formula, R _{1 to} R ₃ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. R _{4 to} R ₆ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a halogen atom, an acyl group, or an acyloxy group. Further, R ₄ and R ₅ , or R ₅ and R ₆ may form a ring. L represents a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof.

Specific examples of L composed of combinations are given below. In the following examples, the left side is bonded to the main chain, and the right side is bonded to the ethylenically unsaturated bond.
L1: -CO-NH-divalent aliphatic group -O-CO-
L2: —CO—divalent aliphatic group —O—CO—
L3: -CO-O-divalent aliphatic group -O-CO-
L4: -Divalent aliphatic group -O-CO-
L5: -CO-NH-divalent aromatic group -O-CO-
L6: -CO-divalent aromatic group -O-CO-
L7: -Divalent aromatic group -O-CO-
L8: -CO-divalent aliphatic group-CO-O-divalent aliphatic group-O-CO-
L9: -CO-divalent aliphatic group-O-CO-divalent aliphatic group-O-CO-
L10: -CO-Divalent aromatic group -CO-O-Divalent aliphatic group -O-CO-
L11: -CO-Divalent aromatic group -O-CO-Divalent aliphatic group -O-CO-
L12: -CO-divalent aliphatic group-CO-O-divalent aromatic group-O-CO-
L13: -CO-Divalent aliphatic group -O-CO-Divalent aromatic group -O-CO-
L14: -CO-divalent aromatic group-CO-O-divalent aromatic group-O-CO-
L15: -CO-Divalent aromatic group -O-CO-Divalent aromatic group -O-CO-
L16: -CO-O-divalent aromatic group -O-CO-NH-divalent aliphatic group -O-CO-
L17: -CO-O-divalent aliphatic group -O-CO-NH-divalent aliphatic group -O-CO-

The divalent aliphatic group means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, a substituted alkynylene group or a polyalkyleneoxy group. Of these, an alkylene group, a substituted alkylene group, an alkenylene group, and a substituted alkenylene group are preferable, and an alkylene group and a substituted alkylene group are more preferable.
The divalent aliphatic group is preferably a chain structure rather than a cyclic structure, and more preferably a linear structure than a branched chain structure.
The number of carbon atoms in the divalent aliphatic group is preferably 1 to 20, more preferably 1 to 15, further preferably 1 to 12, and further preferably 1 to 10. It is preferably 1 to 8, and most preferably.
Examples of the substituent of the divalent aliphatic group include a halogen atom (F, Cl, Br, I), hydroxyl group, carboxyl group, amino group, cyano group, aryl group, alkoxy group, aryloxy group, acyl group , Alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, monoalkylamino group, dialkylamino group, arylamino group and diarylamino group.

The divalent aromatic group means an arylene group or a substituted arylene group. Preferable are phenylene, substituted phenylene group, naphthylene and substituted naphthylene group.
Examples of the substituent for the divalent aromatic group include an alkyl group in addition to the examples of the substituent for the divalent aliphatic group.
Among L1 to L17, L1, L3, L5, L7, and L17 are preferable.

In the formula (I), the repeating unit represented by A ₂ is specifically represented by the following formula (A2).

In formula, R < ₁ > -R < ₃ > and L are synonymous with what is represented by said Formula (A1). Q represents a functional group that interacts with the support surface (hereinafter sometimes abbreviated as “specific functional group”).
Specific functional groups include, for example, covalent bonds, ionic bonds, hydrogen bonds, polar interactions, van der Waals interactions with metals, metal oxides, hydroxyl groups, etc. present on anodized or hydrophilized supports. Examples include groups capable of interaction such as action.
Specific examples of the specific functional group are listed below.

In the above formula, R _{11 to} R ₁₃ each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkynyl group, or an alkenyl group, and M ₁ and M ₂ each independently represent a hydrogen atom, a metal atom, or ammonium. And X ⁻ represents a counter anion.

  Among these, the specific functional group is preferably an onium base such as an ammonium group or a pyridinium group, a β-diketone group such as a phosphate group, a phosphonic acid group, a boric acid group, or an acetylacetone group.

In the formula (A2), L represents a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof. .
Specific examples of L composed of combinations include the following in addition to the specific examples of L in the above (A1). In the following examples, the left side is bonded to the main chain.
L19: -CO-NH-
L20: —CO—O—
L21: -Divalent aromatic group-

In the formula (I), the repeating unit represented by A ₃ is a hydrophilic macromer unit described below.

(Hydrophilic macromonomer)
Among the hydrophilic macromonomers used in the present invention, particularly useful are macromonomers derived from carboxyl group-containing monomers such as acrylic acid and methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and vinylstyrene. Derived from sulfonic acid macromonomer derived from sulfonic acid and its monomer, amide macromonomer such as acrylamide and methacrylamide, N-vinylcarboxylic amide monomer such as N-vinylacetamide and N-vinylformamide Amide macromonomers, macromonomers derived from hydroxyl group-containing monomers such as hydroxyethyl methacrylate, hydroxyethyl acrylate, glycerol monomethacrylate, methoxyethyl acrylate, methoxyethyl methacrylate Acrylate, methoxy polyethylene glycol acrylate, methoxy polyethylene glycol methacrylate, polyethylene glycol acrylate, a macromonomer derived from alkoxy group or ethylene oxide group-containing monomers such as polyethylene glycol methacrylate. A monomer having a polyethylene glycol chain or a polypropylene glycol chain can also be usefully used as the macromonomer of the present invention. Among these macromonomers, the useful polymer has a mass average molecular weight (hereinafter simply referred to as molecular weight) in the range of 400 to 100,000, preferably 1000 to 50,000, and particularly preferably 1500 to 20,000. . When the molecular weight is 400 or less, it is difficult to obtain effective hydrophilicity, and when it is 100,000 or more, the polymerizability with the copolymerization monomer forming the main chain tends to be low.

As long as the specific copolymer of the present invention does not impair the effects of the present invention other than the repeating units represented by A ₁ , A ₂ and A ₃ , one or more selected from the other monomers described below It may be a copolymer of

(Other monomers)
(1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(2) Methyl acrylate, ethyl acrylate, propyl acrylate, amyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate, polyethylene glycol monoacrylate, polypropylene glycol monoalkylate Acrylates and the like.
(3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate, polyethylene glycol monomethacrylate, polypropylene Methacrylates such as glycol monomethacrylate.

(4) Acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.
(5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, and phenyl vinyl ether.
(6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.

(7) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene.
(8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(9) Olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene.
(10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like.
(11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.

The molecular weight of the specific copolymer is 50,000 or more in terms of mass average molecular weight, which is essential from the viewpoint of antifouling properties and printing durability. Further, (A ₁₎ from 1 to 80 mass% is preferable with respect to the total copolymer component, more preferably 2 to 30 mass%. (A ₂ ) is preferably from 1 to 80% by weight, more preferably from 2 to 40% by weight, based on all copolymer components. (A ₃ ) is preferably 10 to 95% by mass, more preferably 20 to 90% by mass, based on all copolymer components.

  Specific examples of the specific copolymer used in the present invention are shown below, but are not limited thereto.

  Formation of the undercoat layer using the specific copolymer is usually carried out by dissolving the specific copolymer in a solvent to prepare a coating solution and coating the support. Examples of the solvent include water and organic solvents such as methanol, ethanol, propanol, isopropanol, ethylene glycol, hexylene glycol, tetrahydrofuran, dimethylformamide, 1-methoxy-2-propanol, dimethylacetamide, and dimethyl sulfoxide. Are preferred. These organic solvents can also be mixed and used.

  As a density | concentration of undercoat layer coating liquid, 0.001-10 mass% is preferable, More preferably, it is 0.01-5 mass%, More preferably, it is 0.05-1 mass%. A surfactant described later may be added to the undercoat layer as necessary. 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 to 200 mg / m ^2, and more preferably 1 to 50 mg / m ^2.

(Polymerized layer)
The polymerization layer of the present invention is sensitive to laser light, and contains (A) an actinic ray absorber, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a binder polymer as main components. Can do. Moreover, a polymerization layer can contain well-known additives other than these as needed. Hereinafter, the components of the polymerization layer will be described.

<(A) Actinic ray absorber>
An actinic ray absorber is a dye having an absorption wavelength corresponding to the wavelength of the laser used for exposure, and is used to efficiently absorb laser light and improve the sensitivity of the lithographic printing plate precursor. Among them, preferable actinic light absorbers include infrared absorbers and sensitizing dyes that absorb light of 360 nm to 450 nm in that the lithographic printing plate precursor can be handled under white light or yellow light. .

(A-1) Infrared Absorber When an image of the lithographic printing plate precursor according to the present invention is formed with a laser that emits infrared rays of 760 to 1200 nm using a light source, it is usually essential to use an infrared absorber. The infrared absorber has a function of converting the absorbed infrared ray into heat and a function of being excited by the infrared ray and transferring electrons / energy to a polymerization initiator (radical generator) described later. The infrared absorber used in the present invention is a dye or pigment 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, JP-A-58-181051, 58-220143, 59-41363, 59-84248, 59-84249 No. 5, 59-146063, 59-146061, pyrium compounds described in JP-A-59-216146, cyanine dyes described in US Pat. No. 4,283,475 The pentamethine thiopyrylium salt and the like, and the pyrylium compounds described in JP-B-5-13514 and JP-A-5-19702 are also preferably used. It is. 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 represented by the following structural formulas. Here, X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. Xa ^- the Za described later ^- is defined as for, Ra represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Preferred substituents include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, an alkoxy group having 12 or less carbon atoms, a hydrocarbon group having 12 or less carbon atoms, and 12 carbon atoms. Most preferred are not more than alkoxy groups. 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. Preferable substituents include an alkoxy group having 12 or less carbon atoms, a carboxyl group, and a sulfo group, and an alkoxy group having 12 or less carbon atoms is most preferable. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (i) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a tetrachloride ion, in view of the storage stability of the recording layer coating solution. Fluoroborate ion, hexafluorophosphate ion, and aryl sulfonate ion.

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

  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 Application 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 polymer layer coating solution and good uniformity of the polymer 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 when the negative lithographic printing plate precursor is prepared, the polymerization layer Is added so that the absorbance at the maximum absorption wavelength in the 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 polymerization layer, and good film strength of the image area and adhesion to the support can be obtained.
The absorbance of the polymerization layer can be adjusted by the amount of the infrared absorber added to the polymerization layer and the thickness of the polymerization layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, a polymerized 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 measured by an optical densitometer. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

  The addition amount of the infrared absorber is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 1 to 20% by mass with respect to the total solid content of the polymerization layer.

(A-2) Sensitizing dye The sensitizing dye used in the present invention preferably has an absorption peak at 350 to 850 nm. Examples of such sensitizing dyes include spectral sensitizing dyes and the following dyes or pigments that absorb light from a light source and interact with a photopolymerization initiator. Among these, those that absorb light of 360 nm to 450 nm that enables operation under white light or yellow light are preferable.

  Preferred spectral sensitizing dyes or dyes include polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thianes). Carbocyanine, oxacarbocyanine), merocyanines (eg, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), phthalocyanines ( For example, phthalocyanine, metal phthalocyanine), porphyrins (for example, tetraphenylporphyrin, central metal-substituted porphyrin), chlorophylls (for example, chlorophyll, chlorophyllin, central gold) Substituted chlorophyll), metal complexes, anthraquinones (e.g., anthraquinone), squaryliums (e.g., squarylium), and the like.

  Examples of more preferable spectral sensitizing dyes or dyes include styryl dyes described in JP-B-37-13034, cationic dyes described in JP-A-62-143044, and quinoxalinium described in JP-B-59-24147. Salts, new methylene blue compounds described in JP-A No. 64-33104, anthraquinones described in JP-A No. 64-56767, benzoxanthene dyes described in JP-A No. 2-1714, JP-A No. 2-226148 and special Acridines described in the respective publications of Kaihei 2-226149, pyrylium salts described in JP-B-40-28499, cyanines described in JP-B-46-42363, benzofuran dyes described in JP-A-2-63053, Conjugated ketone dyes described in JP-A-2-85858 and JP-A-2-216154 HirakiAkira 57-10605 described in JP-dye. Azocinnamylidene derivatives described in JP-B-2-30321, cyanine dyes described in JP-A-1-287105, JP-A-62-31844, JP-A-62-31848, JP-A-62-143043 Xanthene dyes described in Japanese Patent Publication Nos. JP-A Nos. 59-28325, merocyanine dyes described in JP-B No. 61-9621, and dyes described in JP-A No. 2-179433. The merocyanine dye described in JP-A-2-244050, the merocyanine dye described in JP-B-59-28326, the merocyanine dye described in JP-A-8-129257, the benzopyran dye described in JP-A-8-334897, and JP-A-2001-1000041 And styryl compounds described in JP-A-2003-221517.

  The addition amount range of the sensitizing dye is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 1 to 20% by mass with respect to the total solid content constituting the polymerization layer. is there.

<(B) Polymerization initiator>
As the polymerization initiator used in the polymerization layer of the present invention, various photopolymerization initiators known in patents, literatures, etc., or a combination system of two or more photopolymerization initiators (light) depending on the wavelength of the light source used. A polymerization initiation system) can be appropriately selected and used.

  In the case of using a blue semiconductor laser, Ar laser, second harmonic of an infrared semiconductor laser, or SHG-YAG laser as a light source, various photopolymerization initiators (systems) have been proposed. 850,445, certain photoreducible dyes such as rose bengal, eosin, erythrosine, etc., or combinations of dyes and initiators, such as complex initiator systems of dyes and amines. -20099), a combination system of hexaarylbiimidazole, a radical generator and a dye (Japanese Patent Publication No. 45-37377), a system of hexaarylbiimidazole and p-dialkylaminobenzylidene ketone (Japanese Patent Publication No. 47-2528). JP, 54-155292, cyclic cis-α-dicarbonyl compound and dye system (JP 48-8) 183), a system of cyclic triazine and merocyanine dye (Japanese Patent Laid-Open No. 54-151024), a system of 3-ketocoumarin and an activator (Japanese Patent Laid-Open No. 52-112682, Japanese Patent Laid-Open No. 58-15503) , Biimidazole, styrene derivative, thiol system (JP 59-140203 A), organic peroxide and dye system (JP 59-1504 A, JP 59-140203 JP, JP JP-A 59-189340, JP-A 62-174203, JP-B 62-1641, US Pat. No. 4,766,055), a system of dye and active halogen compound (JP-A 63-1718105, JP-A-63-258903, JP-A-3-264771, etc.), a system of a dye and a borate compound (JP-A-62-143044, Japanese Unexamined Patent Publication Nos. 62-150242, 64-13140, 64-13141, 64-13142, 64-13143, 64-13144 JP-A-64-17048, JP-A-1-229003, JP-A-1-298348, JP-A-1-138204, etc.), a system comprising a dye having a rhodanine ring and a radical generator ( JP-A-2-17943, JP-A-2-244050), titanocene and 3-ketocoumarin dye system (JP-A 63-221110), titanocene and xanthene dye, addition polymerization containing amino group or urethane group A combination of possible ethylenically unsaturated compounds (JP-A-4-221958, JP-A-4-219756), Tanosen and system specific merocyanine dye (JP-A-6-295061), a dye system with titanocene and benzopyran ring (JP-A-8-334897 JP), and the like.

  In the polymerization layer (photosensitive layer) of the lithographic printing plate precursor according to the invention, a particularly preferred photopolymerization initiator (system) contains at least one titanocene. The titanocene compound used as a photopolymerizable initiator (system) in the present invention may be any titanocene compound that can generate an active radical when irradiated with light in the presence of a sensitizing dye described later. For example, JP 59-152396 A, JP 61-151197 A, JP 63-41483 A, JP 63-41484 A, JP 2-249 A, and JP 2 -291, JP-A-3-27393, JP-A-3-12403, and JP-A-6-41170 can be appropriately selected and used.

  More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5 , 6-pentafluorophen-1-yl (hereinafter also referred to as “T-1”), di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di- -Cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclo Pentadienyl-Ti-bis-2,4-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl Di-methylcyclopentadi Nyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclo And pentadienyl) -bis (2,6-difluoro-3- (pyr-1-yl) phenyl) titanium (hereinafter also referred to as “T-2”).

  These titanocene compounds can be further subjected to various chemical modifications for improving the properties of the polymerized layer. For example, bonding with sensitizing dyes, addition polymerizable unsaturated compounds and other radical generating parts, introduction of hydrophilic sites, compatibility improvement, introduction of substituents to suppress crystal precipitation, introduction of substituents to improve adhesion A method such as polymerization can be used.

  The use method of these titanocene compounds can be arbitrarily set as appropriate according to the performance design of the lithographic printing plate precursor as in the above-described addition polymerizable compound. For example, the compatibility with the polymerization layer can be increased by using two or more kinds in combination. A larger amount of the photopolymerization initiator such as the titanocene compound is usually advantageous in terms of photosensitivity, and is 0.5 to 80 parts by mass, preferably 1 to 100 parts by mass of the nonvolatile component of the polymerization layer. Sufficient photosensitivity can be obtained by using in the range of 50 parts by mass. On the other hand, when used under a white light such as yellow, it is preferable that the amount of titanocene used is small from the viewpoint of fogging by light near 500 nm, but the amount of titanocene used is 6 parts by mass in combination with a sensitizing dye. Thereafter, sufficient photosensitivity can be obtained even when the content is further reduced to 1.9 parts by mass or less, and further to 1.4 parts by mass or less.

The radical generator used in the present invention is a compound that generates radicals by light, heat, or both, and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. As the radical generator that can be used in the present invention, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, or the like can be used, and a radical that is suitably used in the present invention is generated. The compound to be used refers to a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating a radical by thermal energy. As the thermal radical generator according to the present invention, a known polymerization initiator, a compound having a bond with a small bond dissociation energy, or the like can be appropriately selected and used. Moreover, the compound which generate | occur | produces a radical can be used individually or in combination of 2 or more types.
Examples of the compound that generates radicals include organic halogenated compounds, carbonyl compounds, organic peroxide compounds, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boric acid compounds, disulfonic acid compounds, Examples include oxime ester compounds and onium salt compounds.

  Specific examples of the organic halogenated compound 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-A 48-36281, JP-A 55-32070, JP-A 60-239736, JP-A 61-169835, JP-A 61-169837, JP-A 62-58241, JP 62-212401, JP-A 63-70243, JP-A 63-298339, M.S. P. Hutt “Journal of Heterocyclic Chemistry” 1 (No 3), (1970) ”, and particularly, an oxazole compound substituted with a trihalomethyl group: an S-triazine compound.

  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 2- (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- (pi-propyloxystyryl) -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-Fe Ruthio-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 compound 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, , 5-oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxy Dicarbonate, 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′-tetra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen dihydrogen) Phthalate), carbonyldi (t-hexylperoxydihydrogen diphthalate), and the like.

  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 JP-B-6-29285, US Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. Various compounds described, 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 ′ -Tetraphenylbiimi Sol, 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, JP 2002-107916 A, JP 2764769 A, JP 2002-116539 A, 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 The organic boron iodonium complex described in Japanese Patent No. 5553, the organic boron phosphonium complex described in Japanese Patent Application Laid-Open No. 9-188710, Japanese Patent Application Laid-Open No. 6-348011, Japanese Patent Application Laid-Open No. 7-128785, Japanese Patent Application Laid-Open No. 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 compound include JCS Perkin II (1979) 1653-1660), JCS Perkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, JP 2000-66385 A, JP The compounds described in Japanese Patent Application Laid-Open No. 2000-80068, specifically, compounds represented by the following structural formulas can be mentioned.

  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, 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, 4,734 , 444, 2,833,827, German Patent Nos. 2,904,626, 3,604,580, 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.

  The onium salt suitably used in the present invention is an onium salt represented by the following general formulas (RI-I) to (RI-III).

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 carbon atom. -12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C12 An alkylamino group, a C1-C12 dialkylamino group, a C1-C12 alkylamide group or arylamide group, a carbonyl group, a carboxyl group, a cyano group, a sulfonyl group, a C1-C12 thioalkyl group, A C1-C12 thioaryl group is mentioned. Z ₁₁ ^- represents a monovalent anion, a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, a sulfate ion, stability From the surface, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, and sulfinate ion are preferable.

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 have 1 to 12 carbon atoms. Alkyl group, alkenyl group having 1 to 12 carbon atoms, alkynyl group having 1 to 12 carbon atoms, aryl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, aryloxy group having 1 to 12 carbon atoms, halogen atom An alkylamino group having 1 to 12 carbon atoms, a dialkylamino group having 1 to 12 carbon atoms, an alkylamide group or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxyl group, a cyano group, a sulfonyl group, and 1 carbon atom -12 thioalkyl group and C1-C12 thioaryl group are mentioned. 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 viewpoint of reactivity, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferable.

In the 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 16 substituents. Is preferably an aryl group from the viewpoint of reactivity and stability. 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, a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, stability, From the viewpoint of reactivity, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  Although the specific example of the onium salt compound suitable for this invention is given to the following, it is not limited to these.

In particular, from the viewpoint of reactivity and stability, the above oxime ester compounds, diazonium salts, iodonium salts, and sulfonium salts are preferable. In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
A particularly preferred initiator of the present invention is an iodonium salt having an electron donating group or a sulfonium salt having an electron withdrawing group from the balance of reactivity and stability, and in particular, an alkoxy group or the like in the skeleton having a cation moiety. Most preferred is an iodonium salt having 2 or more, more preferably an iodonium salt having 3 or more alkoxy groups.

  These polymerization initiators may be 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 polymerization layer. it can. 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.

<(C) Polymerizable compound>
The polymerizable compound 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.), and 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 a monofunctional or polyfunctional compound. 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 Sorbitol tetritaconate, etc. Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-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.

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

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (a)
(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 (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like Can also be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

About these addition polymerizable compounds, 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, styrenic compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.
Moreover, 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 polymerization layer (for example, binder polymer, initiator, colorant, etc.). The compatibility may be improved by using a low-purity compound or 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 addition polymerizable compound 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 polymerization layer. These may be used alone or in combination of two or more. In addition, the use method of the addition polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. Depending on the case, a layer configuration and coating method such as undercoating and overcoating can be performed.

<(D) Binder polymer>
As the binder polymer that can be used in the present invention, conventionally known binder polymers can be used without limitation, and 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 may have 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 Mention may be made of polymers having an ethylenically 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, 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, -CH 2 CH = CH 2,} ( described in JP Kokoku _{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.

  In the case of a binder polymer having crosslinkability, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) are added to the crosslinkable functional group, and a polymerization chain of a polymerizable compound is formed directly between 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 to each other so that crosslinking between the polymer molecules occurs. 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 of the unexposed portion of the polymer layer, the binder polymer preferably has high solubility or dispersibility in ink and / or dampening water.
In order to improve the solubility or dispersibility in ink, the binder polymer is preferably lipophilic, and in order to improve the 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 hydrophilic binder polymers include hydroxy groups, carboxyl groups, carboxylate groups, hydroxyethyl groups, polyoxyethyl groups, hydroxypropyl groups, polyoxypropyl groups, amino groups, aminoethyl groups, aminopropyl groups, and ammonium. Preferred are those having a hydrophilic group such as a group, an amide group, a carboxymethyl group, a sulfonic acid group, and 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, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, 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 , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

In the present invention, a binder polymer containing an ether group represented by — [CH ₂ — (CHR) _m —O] _n — in the molecule can also be used. Here, R represents a hydrogen atom or a methyl group, m is 1, 3 or 5, and n represents an integer of 1 to 20. n is preferably an integer of 1 to 7, more preferably an integer of 1 to 4, and most preferably an integer of 1 to 2.
Specific examples include homopolymers or copolymers of acrylates or methacrylates having the ether group in the side chain. Examples of the monomer to be copolymerized include the monomer having the crosslinkable group and other monomers in the description of the specific copolymer.
The hydrophilicity of this ether group is effective for obtaining good on-press developability.

  The binder polymer in the present invention 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 preferably. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The content of the binder polymer in the polymerization layer is preferably 5 to 90% by mass, more preferably 5 to 80% by mass, and 10 to 70% by mass with respect to the total solid content of the polymerization layer. Is more preferable. Within this range, good image area strength and image formability can be obtained.
Moreover, it is preferable to use a polymeric compound and a binder polymer in the quantity used as 0.5 / 1-4/1 by mass ratio.

<Microcapsules and microgels>
In the present invention, several modes can be used as a method for incorporating the above-mentioned polymerization layer components (A) to (D) and other components described later into the polymerization layer. One is a molecular dispersion type polymer layer in which the constituent components are dissolved and applied in a suitable solvent as described in, for example, JP-A-2002-287334. Another aspect is, for example, as described in JP-A-2001-277740 and JP-A-2001-277742, a microcapsule in which all or part of the constituent components are encapsulated and contained in a polymerization layer. It is a capsule type polymerization layer. Furthermore, in the microcapsule type polymerization layer, the constituent component can be contained outside the microcapsule. Here, it is preferable that the microcapsule-type polymerization 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 polymerized layer contains crosslinked resin particles, that is, microgel. The microgel can contain a part of the constituent components (A) to (D) in and / or on the surface thereof. In particular, an embodiment in which (C) a reactive microgel is formed by having a polymerizable compound on the surface thereof is particularly preferable from the viewpoint of image forming sensitivity and printing durability.
In order to obtain better on-press developability, the polymerization layer is preferably a microcapsule type or a microgel type polymerization layer.

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, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, 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. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into the below-mentioned binder polymer.

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, as described in JP-A-5-61214, etc. It is possible to utilize granulation by non-aqueous dispersion polymerization. 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 polymerization layer in order to promote 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 10% by mass with respect to the total solid content of the polymerization 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 amount added is preferably 0.01 to 10% by mass relative to the total solid content of the image recording material.

<Bakeout agent>
In the polymerization layer of the present invention, a compound that changes color by an acid or a radical can be added to produce a printout image. As such a compound, 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 "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by 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 15% by mass relative to the solid content of the polymerized layer.

<Polymerization inhibitor>
In order to prevent unnecessary thermal polymerization of the (C) radical polymerizable compound during the production or storage of the polymerization layer, it is preferable to add a small amount of a thermal polymerization inhibitor to the polymerization layer of the present invention.
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), and 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 polymerization layer.

<Higher fatty acid derivatives, etc.>
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to the polymerization layer of the present invention so that it is unevenly distributed on the surface of the polymerization layer in the course of drying after coating. May be. 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 polymerization layer.

<Plasticizer>
The polymerization layer of the present invention may contain a plasticizer in order to improve 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 content of the plasticizer is preferably about 30% by mass or less with respect to the total solid content of the polymerization layer.

<Inorganic fine particles>
The polymerized layer of the present invention may contain inorganic fine particles for improving the strength of the cured film in the image area and improving the 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 can be preferably mentioned. 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 μm to 3 μm. Within the above range, it is possible to form a non-image portion having excellent hydrophilicity that is stably dispersed in the polymerized layer, sufficiently retains the film strength of the polymerized layer, and does not easily cause 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 40% by mass or less, and more preferably 30% by mass or less, based on the total solid content of the polymerization layer.

<Low molecular hydrophilic compound>
The polymerized layer of the present invention may contain a hydrophilic low molecular compound for improving on-press developability. Examples of hydrophilic low molecular weight compounds include water-soluble organic compounds such as glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol, 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 polymerization layer>
The polymerized layer of the present invention is coated by preparing a coating solution by dispersing or dissolving the necessary components described above in a solvent. 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-butyllactone, 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 polymerized 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 repeatedly applying and drying a plurality of times.

Moreover, although the application amount (solid content) of the polymer layer on the support obtained after coating and drying varies depending on the application, it is generally preferably 0.3 to 3.0 g / m ² . 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.

[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. Among these, Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si
It is preferable to use a silicon alkoxy compound such as (OC ₄ H ₉ ) ₄ because the raw material is inexpensive and easily available.

[Protective layer]
In the lithographic printing plate precursor according to the present invention, a protective layer (on the polymerization layer, if necessary) may be added to provide oxygen barrier properties, prevent the occurrence of scratches in the polymerization layer, and prevent ablation that occurs during high-illuminance laser exposure. Overcoat layer) can be provided.
Usually, the exposure processing of a lithographic printing plate is carried out in the atmosphere. The image forming reaction in the polymerized layer caused by the exposure process can be inhibited by low molecular weight 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 polymerization layer, and as a result, suppresses the image formation inhibition reaction in the atmosphere. Therefore, the properties desired for the protective layer are to reduce the permeability of low-molecular compounds such as oxygen, furthermore, the transparency of light used for exposure is good, the adhesiveness with the polymerized layer is excellent, and It can be easily removed in the on-press development process after exposure. The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and JP-B-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 esters, ethers, and acetals as long as they contain a substantial amount of unsubstituted vinyl alcohol units 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 the modified polyvinyl alcohol 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, PVA124H, 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 etc. are mentioned. 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. Is a particle having a thin tabular shape and layered compound, for example, the following general formula _{A (B, C) 2-5 D} 4 O 10 (OH, F, O) 2
[However, A is any one of K, Na, and Ca, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, and 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. Synthetic mica includes non-swellable 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} /5 Li Examples thereof include swelling mica such as _1/8 (Si ₄ O ₁₀ ) F ₂ . Synthetic smectites are also useful.

Of 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, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and metal atom substitution in the lattice is other than Significantly greater than viscous minerals. As a result, the lattice layer is deficient in positive charge, and in order to compensate for this, the layers such as Li ⁺ , Na ⁺ , Ca ²⁺ , Mg ²⁺ , amine salts, quaternary ammonium salts, phosphonium salts and sulfonium salts are used. Adsorbs organic cation 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 swellable 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 plane size as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Therefore, 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 about 1 to 50 nm in thickness and about 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 inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

  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. The addition amount of these activators can be added in an amount of 0.1 to 100% by mass with respect 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 include an acrylic polymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass of a water-based emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer, and the like, and laminating on a polymerization 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 the well-known additive for improving the adhesiveness with a polymerization layer and the temporal stability of a coating liquid to this coating liquid.

  The protective layer coating solution thus prepared is applied onto the polymer 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. It is in the range of 02 to 1 g / m ² .

[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. Preferable supports include 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 different 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 from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 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 polymerized 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. Also, a transfer method in which the uneven shape is transferred with a roll provided with unevenness in the aluminum rolling step may 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 of anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, an electrolyte concentration of 1 to 80% by mass solution, a liquid temperature of 5 to 70 ° C., a current density of 5 to 60 A / d m 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.

As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, immersion in an aqueous solution containing a micropore enlargement treatment, sealing treatment and a hydrophilic compound described in JP-A-2001-253181 or JP-A-2001-322365 The surface hydrophilization treatment to be performed can be appropriately selected and performed. Of course, the enlargement process and the sealing process are not limited to those described above, and any conventionally known method can be performed.
For example, as the sealing treatment, in addition to the vapor sealing, a single treatment with fluorinated zirconic acid, a treatment with sodium fluoride, or a vapor sealing with addition of lithium chloride is possible.

<Sealing treatment>
The sealing treatment used in the present invention is not particularly limited, and a conventionally known method can be used. Among them, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and hot water. Sealing treatment is preferred. Each will be described below.

<Sealing treatment with an aqueous solution containing an inorganic fluorine compound>
As the inorganic fluorine compound used for the sealing treatment with an aqueous solution containing an inorganic fluorine compound, a metal fluoride is preferably exemplified.
Specifically, for example, sodium fluoride, potassium fluoride, calcium fluoride, magnesium fluoride, sodium fluoride zirconate, potassium fluoride zirconate, sodium fluoride titanate, potassium fluoride titanate, zircon fluoride Ammonium acid, ammonium fluoride titanate, potassium fluoride titanate, fluorinated zirconate, fluorinated titanate, hexafluorosilicic acid, nickel fluoride, iron fluoride, phosphor fluoride, ammonium fluoride phosphate It is done. Of these, sodium fluorinated zirconate, sodium fluorinated titanate, fluorinated zirconic acid, and fluorinated titanic acid are preferable.

  The concentration of the inorganic fluorine compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, from the viewpoint of sufficiently sealing the micropores of the anodized film. Further, in terms of stain resistance, it is preferably 1% by mass or less, and more preferably 0.5% by mass or less.

  It is preferable that the aqueous solution containing the inorganic fluorine compound further contains a phosphate compound. When the phosphate compound is contained, the hydrophilicity of the surface of the anodized film is improved, so that on-machine developability and stain resistance can be improved.

Suitable examples of the phosphate compound include phosphates of metals such as alkali metals and alkaline earth metals.
Specifically, for example, zinc phosphate, aluminum phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, monoammonium phosphate, monopotassium phosphate, monosodium phosphate, dihydrogen phosphate Potassium, dipotassium hydrogen phosphate, calcium phosphate, sodium ammonium hydrogen phosphate, magnesium hydrogen phosphate, magnesium phosphate, ferrous phosphate, ferric phosphate, sodium dihydrogen phosphate, sodium phosphate, hydrogen phosphate Disodium, lead phosphate, diammonium phosphate, calcium dihydrogen phosphate, lithium phosphate, phosphotungstic acid, ammonium phosphotungstate, sodium phosphotungstate, ammonium phosphomolybdate, sodium phosphomolybdate, sodium phosphite , Tripolyphosphate Potassium, and sodium pyrophosphate. Of these, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate are preferable.
The combination of the inorganic fluorine compound and the phosphate compound is not particularly limited, but the aqueous solution contains at least sodium zirconate fluoride as the inorganic fluorine compound and contains at least sodium dihydrogen phosphate as the phosphate compound. Is preferred.

  The concentration of the phosphate compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of improving on-press developability and stain resistance. Further, in terms of solubility, it is preferably 20% by mass or less, and more preferably 5% by mass or less.

The ratio of each compound in the aqueous solution is not particularly limited, but the mass ratio of the inorganic fluorine compound and the phosphate compound is preferably 1/200 to 10/1, and preferably 1/30 to 2/1. Is more preferable.
The temperature of the aqueous solution is preferably 20 ° C. or higher, more preferably 40 ° C. or higher, preferably 100 ° C. or lower, more preferably 80 ° C. or lower.
The aqueous solution preferably has a pH of 1 or more, more preferably has a pH of 2 or more, preferably has a pH of 11 or less, and more preferably has a pH of 5 or less.
The method for sealing with an aqueous solution containing an inorganic fluorine compound is not particularly limited, and examples thereof include an immersion method and a spray method. These may be used alone or in combination, or may be used in combination of two or more.
Of these, the dipping method is preferred. When the treatment is performed using the dipping method, the treatment time is preferably 1 second or longer, more preferably 3 seconds or longer, and preferably 100 seconds or shorter, and 20 seconds or shorter. More preferred.

<Sealing treatment with water vapor>
Examples of the sealing treatment with water vapor include a method of bringing pressurized or normal pressure water vapor into contact with the anodized film continuously or discontinuously.
The temperature of the water vapor is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 105 ° C. or lower.
The water vapor pressure is preferably in the range (1.008 × 10 ^{5 to} 1.043 × 10 ⁵ Pa) from (atmospheric pressure−50 mmAq) to (atmospheric pressure + 300 mmAq).
Further, the time for which the water vapor is contacted is preferably 1 second or longer, more preferably 3 seconds or longer, 100 seconds or shorter, more preferably 20 seconds or shorter.

<Sealing treatment with hot water>
Examples of the sealing treatment with water vapor include a method in which an aluminum plate on which an anodized film is formed is immersed in hot water.
The hot water may contain an inorganic salt (for example, phosphate) or an organic salt.
The temperature of the hot water is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 100 ° C. or lower.
Further, the time of immersion in hot water is preferably 1 second or longer, more preferably 3 seconds or longer, more preferably 100 seconds or shorter, and even more preferably 20 seconds or shorter.

<Hydrophilic treatment>
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.

  When using a support having insufficient surface hydrophilicity, such as a polyester film, as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

  The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the polymerized layer, good printing durability and good stain resistance can be obtained.

II. Lithographic printing method As a light source for exposing the lithographic printing plate precursor according to the invention, a known light source can be used without limitation. The wavelength of a desirable light source is 300 nm to 1200 nm, and specific examples include a carbon arc lamp, a mercury lamp, a xeno lamp, a metal hydrado lamp, a strobe, an ultraviolet ray, an infrared ray, and a laser beam. A laser is particularly preferable, and examples thereof include a solid-state laser and a semiconductor laser that emit infrared light of 760 to 1200 nm, an ultraviolet semiconductor laser that emits light of 360 nm to 450 nm, an argon ion laser that emits visible light, and an FD-YAG laser. Among these, from the viewpoint of simplification of plate making, a laser that emits infrared rays or ultraviolet rays that can be operated under white light or yellow light is particularly preferable.
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 >.
Specifically, an InGaN-based semiconductor laser is suitable as the ultraviolet laser. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like, but a multi-beam exposure apparatus with a total output of 20 mW or more is preferable.

The lithographic printing method using the lithographic printing plate precursor of the present invention is not particularly limited, but preferably, for example, the lithographic printing plate precursor of the present invention is imagewise exposed with a laser such as an infrared laser, An example is a method in which oil-based ink and an aqueous component are supplied and printed without going through a development processing step.
As a preferred specific method, a method in which a lithographic printing plate precursor is exposed to a laser and then mounted on a printing machine without passing through a development process, and a lithographic printing plate precursor is mounted on a printing machine and then on a printing machine. And a method of printing without passing through a development processing step.

After the lithographic printing plate precursor is imagewise exposed with a laser and then supplied with an aqueous component and an oil-based ink without passing through a development process such as a wet development process, printing is performed at the exposed portion of the polymerization layer. The cured polymer layer forms an oil-based ink receiving part having a lipophilic surface. On the other hand, in the unexposed area, the uncured polymer 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 polymerized layer in the exposed area, and printing is started. Here, the water-based component or oil-based ink may be supplied first to the plate surface, but the oil-based ink is first supplied in order to prevent the water-based component from being contaminated by the polymer layer in the unexposed area. It is preferable to do this. As the aqueous component and oil-based ink, dampening water and printing ink for ordinary lithographic printing are 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.

  In addition, the lithographic printing method of the present invention includes a method in which a lithographic printing plate precursor is imagewise exposed with a laser and then developed using a non-alkaline aqueous solution having a pH of 10 or less as a developer, followed by printing. it can. As the non-alkaline aqueous solution that can be used here, for example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. The aqueous solution containing an aqueous solution or a surfactant (anionic, nonionic, cationic, etc.) is preferred. The pH of the developer is preferably from 2 to 10, more preferably from 3 to 9, and even more preferably from 5 to 9. .

The non-alkali aqueous solution that can be used as the developer may contain an organic acid, an inorganic acid, an inorganic salt, or the like.
Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt. The content in the developer is preferably 0.01 to 5% by mass.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like. The content in the developer is preferably 0.01 to 5% by mass.

  Examples of the anionic surfactant that can be used in the developer used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts, dialkylsulfosuccinates, linear alkylbenzenesulfonic acid salts, Branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamides Sodium salts, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate esters, alkyl sulfate esters, polyoxyethylene alkyl ether sulfates Ester salt, fatty acid monoglyceride sulfate ester, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate Examples thereof include ester salts, partially saponified products of styrene-maleic anhydride copolymer, partially saponified products of olefin-maleic anhydride copolymer, and naphthalene sulfonate formalin condensates. Of these, dialkylsulfosuccinates, alkylsulfate esters and alkylnaphthalenesulfonates are particularly preferably used.

  The cationic surfactant that can be used in the developer 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.

Nonionic surfactants that can be used in the developer used in the present invention include polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide Adducts, higher alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts, fat and oil ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, dimethylsiloxane-ethylene oxide block copolymers, dimethylsiloxane- (propylene oxide-ethylene oxide) Block copolymer, fatty acid ester of polyhydric alcohol glycerol, fatty acid ester of pentaerythritol, Bitoru and fatty acid esters of sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.
These nonionic surfactants may be used alone or in combination of two or more. In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the developer of the present invention is HLB (Hydrophile-Lipophile).
The (Balance) value is preferably 6 or more, and more preferably 8 or more.
Furthermore, the ratio of the nonionic surfactant contained in the developer is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass.
Also, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.
As the surfactant used in the developer of the present invention, a nonionic surfactant is particularly suitable from the viewpoint of foam suppression.

The developer used in the present invention may contain an organic solvent. Examples of the organic solvent that can be contained here include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H
, G "(Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichrene, monochlorobenzene, etc.), The following polar solvents are mentioned.
Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol mono Ethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl Alcoa Etc.), ketones (acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl) Acetate, propylene glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).

  When the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the developer contains an organic solvent, the concentration of the solvent is preferably less than 40% by mass from the viewpoint of safety and flammability.

  In the developer used in the present invention, as a water-soluble polymer compound, soybean polysaccharide, modified starch, gum arabic, dextrin, fiber derivative (for example, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, Pullulan, polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, etc. Can be contained.

    A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.
Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, and more preferably from 0.5 to 10% by mass.

  In addition to the above, the developer used in the present invention may contain a preservative, a chelate compound, an antifoaming agent and the like.

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzisothiazolin-3-one, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, pyridine, Derivatives such as quinoline and guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.

  Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.

  As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, or nonionic surfactant having a HLB of 5 or less can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used.

The development processing with a non-alkaline aqueous solution in the present invention can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. As the automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs rubbing while conveying a lithographic printing plate precursor after image recording, Automatic processing for rubbing the lithographic printing plate precursor after image recording set on the cylinder described in the specifications of Patent No. 5148746, US Pat. No. 5,568,768 and British Patent No. 2297719, while rotating the cylinder Machine. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable. In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water, dried and desensitized.
Although the temperature of the developer can be used at any temperature, it is preferably 10 ° C to 50 ° C.
[Example]
Hereinafter, although an example and a comparative example explain the present invention in detail, the present invention is not limited to these.

(Production 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 degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was 0.3 mm. The aluminum surface was grained using three bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed thoroughly with water. 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. The etching amount of the grained surface at this time 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 nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 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 the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode.
Then, water washing by spraying was performed.

Next, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a direct current anodic oxide coating 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, dried and supported. Body A. 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.

[Synthesis Example of Specific Graft Polymer (1)]
(Synthesis of macromers)
In a 300 ml three-necked flask equipped with a condenser and a stirrer, 20 g of 2-hydroxyethyl methacrylate and 3.8 g of 3-mercaptopropionic acid were dissolved in 70 g of 1-methyl-2-pyrrolidone, heated to 60 ° C. in a nitrogen atmosphere, and subjected to thermal polymerization. Initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) 0.17 g was added and reacted for 6 hours to obtain a terminal carboxylic acid prepolymer (acid value 1.05 meq / g, molecular weight 1.29 × 10 ^3). ). Further, 9.5 g of α-bromomethyl methacrylate, 3.5 g of triethylamine and 10 mg of p-methoxyphenol were added and reacted at 60 ° C. for 6 hours. After the reaction, reprecipitation with ethyl acetate and washing with methanol were sufficient to obtain a macromer. (Mass average molecular weight 1.35 × 10 ³ ).

(Synthesis of graft polymer)
60 g of 1-methyl-2-pyrrolidone was placed in a 1 L three-necked flask equipped with a condenser and a stirrer, and heated to 75 ° C. under a nitrogen stream. 33 g of Phosmer-PE (manufactured by Unichemical Co., Ltd.), 65 g of acrylamide-2-methylpropanesulfonic acid, 6 g of the macromer, V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) 0.65 g, 1-methyl-2- A solution of 120 g of pyrrolidone was added dropwise over 2 hours. After completion of dropping, the mixture was further stirred for 2 hours. After nitrogen was stopped and the reaction solution was cooled to room temperature, 25 g of 2-methacryloyloxyethyl isocyanate, 0.3 g of benzoquinone, and 0.6 g of Neostan U-600 (manufactured by Nitto Kasei Co., Ltd.) were added, and the mixture was heated and stirred at 60 ° C. went. Six hours later, 50 g of methanol was added, unreacted 2-methacryloyloxyethyl isocyanate was deactivated, and the reaction solution was cooled to room temperature.
It was confirmed by ¹ H-NMR spectrum that a double bond was introduced into the side chain by the polymer reaction. As a result of measuring the mass average molecular weight by gel permeation chromatography (GPC) using polyacrylic acid as a standard substance, it was 90,000.

[Synthesis Example of Specific Graft Polymer (44)]
(Synthesis of macromers)
In a 300 ml three-necked flask equipped with a condenser and a stirrer, 20 g of allyl methacrylate and 2.8 g of mercaptoethanol were dissolved in 70 g of 1-methyl-2-pyrrolidone. 0.17 g (manufactured by Wako Pure Chemical Industries, Ltd.) was added and reacted for 6 hours to obtain a terminal alcohol prepolymer (molecular weight 1.33 × 10 ³ ). Further, 6.7 g of 2-methacryloyloxyethyl methacrylate, 10 mg of benzoquinone and 0.3 g of Neostan U-600 (manufactured by Nitto Kasei Co., Ltd.) were added and reacted at 60 ° C. for 6 hours. After the reaction, reprecipitation with ethyl acetate was performed. The polymer was sufficiently washed with methanol to obtain a macromer (mass average molecular weight 1.40 × 10 ³ ).

(Synthesis of graft polymer)
60 g of 1-methyl-2-pyrrolidone was placed in a 1 L three-necked flask equipped with a condenser and a stirrer, and heated to 75 ° C. under a nitrogen stream. A solution of 33 g of ethylene glycol acetoacetate methacrylate, 65 g of acrylamide-2-methylpropanesulfonic acid, 5 g of the above macromer, 0.65 g of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.), and 120 g of 1-methyl-2-pyrrolidone It was added dropwise over time. After completion of dropping, the mixture was further stirred for 2 hours to obtain a specific graft polymer (22). The mass average molecular weight measured by gel permeation chromatography (GPC) using polyacrylic acid as a standard substance was 80,000.

[Example 1]
Formation of Undercoat Layer The following undercoat liquid (1) was bar-coated on the support prepared above, and then oven-dried at 100 ° C. for 60 seconds to form an undercoat layer having a dry coating amount of 10 mg / m ² .

Undercoat liquid (1)
-Specific graft polymer (1) (mass average molecular weight 90,000) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

Formation of Polymerized Layer and Protective Layer After applying the polymer layer coating solution (1) having the following composition on the support on which the undercoat layer was formed, it was oven-dried at 100 ° C. for 60 seconds, and the dry coating amount was 1. A lithographic printing plate precursor was obtained by forming a polymerization layer of 0 g / m ² . Subsequently, the protective layer coating solution (1) having the following composition is bar-coated on the polymerized 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. A printing plate master was obtained.

  The polymerization layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microcapsule solution (1) immediately before coating.

Photosensitive solution (1)
-Binder polymer (1) 0.162g
・ Polymerization initiator (1) 0.100 g
・ Infrared absorber (1) 0.020 g
Polymerizable compound, Aronix M-215 (manufactured by Toa Gosei Co., Ltd.) 0.385 g
・ Fluorosurfactant (1) 0.044g
・ Methyl ethyl ketone 1.091g
・ 1-methoxy-2-propanol 8.609g
Microcapsule liquid (1)
・ Microcapsule synthesized as follows (1) 2.640 g
・ Water 2.425g

Protective layer coating solution (1)
-1.5g of the following inorganic particle dispersion (1)
・ Polyvinyl alcohol PVA105 0.06g
(Kuraray Co., Ltd., degree of saponification 98.5 mol%, degree of polymerization 500)
・ Polyvinylpyrrolidone K30 0.01g
(Made by Tokyo Chemical Industry Co., Ltd., molecular weight Mw = 40,000)
・ Copolymer of vinylpyrrolidone and vinyl acetate 0.01g
LUVITEC VA64W (manufactured by ISP, copolymerization ratio = 6/4)
・ Nonionic surfactant Emarex 710 0.01g
(Nippon Emulsion Co., Ltd.)
・ Ion-exchanged water 6.0g

Synthesis of microcapsule (1) As an oil phase component, 10 g of trimethylolpropane and xylene diisocyanate adduct (manufactured by Mitsui Takeda Chemical Co., Ltd., Takenate D-110N, 75 mass% ethyl acetate solution), Aronix M-215 ( Toagosei Co., Ltd. (6.00 g) and Pionein 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 12000 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 solution thus obtained was diluted with distilled water so that the solid content concentration was 15% by mass. The average particle size was 0.2 μm.

Preparation of inorganic particle 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 the average particle size (laser scattering method) was determined using a homogenizer. Disperse until 3 μm. The aspect ratio of the obtained dispersed inorganic particles was 100 or more.

[Examples 2 to 5]
An undercoat layer is formed in the same manner as in Example 1 except that the specific copolymer of the undercoat liquid (1) is replaced with the specific copolymer described in Table 1, and a polymer layer similar to that in Example 1 is further formed thereon. Then, a lithographic printing plate precursor was obtained by forming a protective layer.

[Comparative Example 1]
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the following comparative polymer (1) (mass average molecular weight 50,000) was used in place of the specific graft polymer, and Comparative Example 1 was obtained.

Example 6
Formation of Undercoat Layer The following undercoat liquid (2) was bar-coated on the support prepared above, and then oven-dried at 100 ° C. for 60 seconds to form an undercoat layer having a dry coating amount of 10 mg / m ² .

Undercoat liquid (2)
Specific graft polymer (7) (mass average molecular weight 100,000) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

Formation of Polymerized Layer After applying the polymer layer coating solution (2) having the following composition onto the support on which the undercoat layer was formed, it was oven-dried at 100 ° C. for 60 seconds, and the dry coating amount was 1.0 g / m. ² polymerization layers were formed, and the same protective layer as in Example 1 was further provided to obtain a lithographic printing plate precursor.

Polymerization layer coating solution (2)
・ Infrared absorber (2) 0.05g
-Polymerization initiator (1) 0.20g
-Binder polymer (2) (average molecular weight 80,000) 0.50 g
Polymerizable compound, Aronix M-215 (manufactured by Toa Gosei Co., Ltd.) 1.00 g
・ Victoria Pure Blue Naphthalenesulfonate 0.02g
・ Fluorosurfactant (1) 0.10g
・ Methyl ethyl ketone 18.0g

[Examples 7 to 10]
An undercoat layer was formed in the same manner as in Example 1 except that the specific copolymer in the undercoat liquid (2) was changed to the specific copolymer shown in Table 2, and a polymer layer similar to that in Example 1 was further formed thereon. Then, a lithographic printing plate precursor was obtained by forming a protective layer.

[Comparative Example 2]
A lithographic printing plate precursor was prepared in the same manner as in Example 6 except that the following comparative polymer (2) (mass average molecular weight 50,000) was used in place of the specific graft polymer, and used as Comparative Example 2.

[Exposure and printing]
Each lithographic printing plate precursor obtained in the above Examples and Comparative Examples was exposed with a Trendsetter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2400 dpi. The exposure image includes a thin line chart. The obtained exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. Dampening water (EU-3 (Effect manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink Chemical Co., Ltd.) After supplying dampening water and ink, 100 sheets were printed at a printing speed of 6000 sheets per hour.
When the on-press development of the unexposed portion of the polymerized layer was completed on the printing press and the number of printing papers required until the ink was not transferred to the printing paper was measured as on-press developability, any lithographic plate Even when the printing plate precursor was used, a printed matter having no non-image area stain was obtained within 100 sheets.

[Evaluation of planographic printing plate precursor]
The lithographic printing plate obtained above was evaluated for stain resistance, neglected stain resistance, fine line reproducibility, and printing durability by the following methods. The results are shown in Table 3.

(1) Dirt prevention property The blanket was stained visually after printing 10,000 sheets. The antifouling property was evaluated on a 10-point scale according to the degree of dirt on the blanket. Larger numbers indicate better antifouling properties. The results are shown in Table 3.

(2) Leaving stain prevention property In the above stain prevention property evaluation, after printing 10,000 sheets, the plate was allowed to stand for 1 hour, and then printing was started again to visually evaluate the stain on the blanket in the non-image area. . The left-stained anti-stain property was evaluated on a 10-point scale from the one with a lesser level of blanket contamination. The results are shown in Table 3.

(3) 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 based on the fine line width that was observed and reproduced with ink without interruption. The results are shown in Table 3.

(4) 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 polymerization 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 results are shown in Table 3.

[Examples 11 to 15]
Formation of undercoat layer The following undercoat liquid (3) was bar-coated on the support prepared as described above, followed by oven drying at 100 ° C. for 60 seconds to form an undercoat layer having a dry coating amount of 10 mg / m ² . .

Undercoat liquid (3)
-Specific copolymer (described in Table 4) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

Formation of Polymerized Layer and Protective Layer After applying a polymer layer coating solution (3) having the following composition onto the above undercoat layer, it was oven-dried at 100 ° C. for 60 seconds, and the dry coating amount was 1.0 g / m ² . A polymerization layer is formed, and a protective layer coating solution (2) having the following composition is coated thereon so that the dry coating amount is 0.5 g / m ^2, and dried at 120 ° C. for 1 minute to be a lithographic printing plate precursor Got.

Polymerization layer coating solution (3)
・ The following polymerization initiator (2) 0.2 g
・ The following sensitizing dye (1) 0.5 g
-Binder polymer (1) 6.0g
・ Polymerizable compound, isocyanuric acid EO-modified triacrylate 12.4 g
(M-315 manufactured by Toa Gosei Co., Ltd.)
・ Royco Crystal Violet 3.0g
-Thermal polymerization inhibitor, N-nitrosophenylhydroxylamine aluminum salt 0.1 g
・ Tetraethylammonium chloride 0.1g
・ Fluorine-based surfactant (1) 0.1g
・ Methyl ethyl ketone 70.0g

Protective layer coating solution (2)
Polyvinyl alcohol (saponification degree 95 mol%, polymerization degree 800) 40 g
・ Polyvinylpyrrolidone (molecular weight 50,000) 5g
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight of 75 g
・ 950g of water

[Comparative Example 3]
A lithographic printing plate precursor was prepared in the same manner as in Example 11 except that the comparative polymer (1) (mass average molecular weight 50,000) was used instead of the specific graft polymer, and Comparative Example 3 was obtained.

[Examples 16 to 20]
Formation of undercoat layer The following undercoat liquid (4) was bar-coated on the support prepared as described above, followed by oven drying at 100 ° C. for 60 seconds to form an undercoat layer having a dry coating amount of 10 mg / m ² . .

Undercoat liquid (4)
-Specific copolymer (described in Table 5) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

Formation of Polymerization Layer and Protective Layer A lithographic printing plate precursor was obtained in the same manner as in Examples 11 to 15 except that the polymerization layer coating solution (3) was changed to a polymerization layer coating solution (4) having the following composition.

Polymerization layer coating solution (4)
・ The following polymerization initiator (3) 0.2 g
-Binder polymer (2) 3.0g
・ Polymerizable compound, isocyanuric acid EO-modified triacrylate 6.2 g
(M-315 manufactured by Toa Gosei Co., Ltd.)
・ Royco Crystal Violet 3.0g
-Thermal polymerization initiator, N-nitrosophenylhydroxylamine aluminum salt 0.1 g
・ Fluorine-based surfactant (1) 0.1g
・ Microcapsule (1) (in terms of solid content) 10.0 g
・ Methyl ethyl ketone 35.0g
・ 35.0 g of 1-methoxy-2-propanol
・ Water 10.0g

[Comparative Example 4]
A lithographic printing plate precursor was prepared in the same manner as in Example 16 except that comparative polymer (2) (mass average molecular weight 50,000) was used instead of the specific graft polymer, and it was designated as comparative example 4.

[Exposure and printing]
The planographic printing plate precursor was exposed with a 375 nm or 405 nm semiconductor laser under the conditions of an output of 2 mW, an outer drum with a peripheral length of 900 mm, a drum rotation speed of 800 rpm, and a resolution of 2400 dpi. The one pixel drawing time is as shown in Table 7.

  The lithographic printing plate precursor was mounted on a SOR-M cylinder made by Heidelberg without developing the exposed exposed master plate, and dampening water (EU-3 (Etchi solution manufactured by Fuji Photo Film Co., Ltd.)) / Water / Isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) are used, and after supplying dampening water and ink, every hour 100 sheets were printed at a printing speed of 6000 sheets. All the lithographic printing plate precursors had 100 sheets or less, and the removal of the unexposed portion of the polymerization layer on the printing machine was completed, and good on-press developability was exhibited.

[Evaluation of planographic printing plate precursor]
The anti-stain property, anti-stain property property, fine line reproducibility and printing durability were evaluated in the same manner as in Examples 1-10. Sensitivity and white light safety were evaluated as follows. The evaluation results are shown in Table 6.

(5) Sensitivity After performing 100 sheets of printing using the lithographic printing plate precursor exposed with the exposure amount of the plate surface exposed in the above-mentioned exposure, it was confirmed that a printed matter free from ink stains was obtained in the non-image area. 500 sheets were printed. In the total 600th printed matter, the exposure amount with no unevenness in the ink density in the image area was measured as sensitivity.

(6) White light safety An unexposed lithographic printing plate precursor was placed under a white fluorescent lamp and placed under conditions where the amount of light was 400 lux on the surface of the lithographic printing plate precursor, and was exposed. These lithographic printing plate precursors exposed to white light were subjected to development processing for those requiring development processing, and then attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg, and printed 100 sheets as described above. Thereafter, the exposure time was measured under a white fluorescent lamp where no ink smear occurred. The longer this time, the better the white light safety.

Claims (4)

  A lithographic printing plate precursor having an undercoat layer and a laser light-sensitive polymer layer on a hydrophilic support and capable of forming an image without alkali development, wherein the undercoat layer has at least (a1) an ethylenically unsaturated bond And (a2) a polymer compound having a repeating unit having at least one functional group that interacts with the support surface and (a3) a repeating unit having at least one hydrophilic functional group. The lithographic printing plate precursor, wherein the polymer compound is (a1) a graft polymer having a branched polymer containing a repeating unit having at least one ethylenically unsaturated bond.   The lithographic printing plate precursor as claimed in claim 1, wherein the polymerization layer contains an infrared absorber.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the polymerized layer contains microcapsules or microgels.   The lithographic printing plate precursor according to any one of claims 1 to 3 is mounted on a printing machine and imagewise laser-exposed, or after imagewise exposure with a laser and then mounted on a printing machine, A lithographic printing method in which printing ink and fountain solution are supplied to the lithographic printing plate precursor to remove a laser unexposed portion of the polymerized layer and print.