JP2002166674A - Original plate for lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original plate for a lithographic printing plate having good on-press developability and an excellent plate wear resistance. SOLUTION: The original plate for the lithographic printing plate comprises an image forming layer containing fine particles including at least one type selected from the group consisting of a phenol resin, an acrylic resin, a urethane resin and an epoxy resin. It is preferable that the fine particles contain a photothermal conversion agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor, and more particularly to a lithographic printing plate precursor having excellent adhesion to an aluminum support and excellent film forming properties, and thereby having excellent printing durability.

[0002]

2. Description of the Related Art Numerous studies have been made on printing plates for computer-to-plate systems, which have been remarkably advanced in recent years. Among them, with the aim of further streamlining the process and solving the problem of waste liquid treatment, development-free lithographic printing plate precursors that can be mounted on a printing press and printed without developing after exposure have been studied, and various methods have been studied. Proposed.

[0003] One of the methods for eliminating the processing step is to mount an exposed printing plate precursor on a cylinder of a printing press, and supply a dampening solution and ink while rotating the cylinder. There is a method called on-press development for removing an image portion. In other words, the printing plate precursor is mounted on a printing machine as it is after exposure, and the processing is completed in a normal printing process. A lithographic printing plate precursor suitable for such on-press development has a photosensitive layer that is soluble in fountain solution and ink solvent, and is suitable for development on a printing machine placed in a bright room. It is required to have a light room handling property.

For example, Japanese Patent Application Laid-Open No. 9-131850 discloses a lithographic printing plate precursor in which a photosensitive layer in which fine particles of a thermoplastic hydrophobic polymer are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support. It has been disclosed. In this publication,
In the lithographic printing plate precursor, an image is formed by exposing the thermoplastic hydrophobic polymer fine particles by heat by exposing the plate to infrared rays, and then mounting the plate on a printing press cylinder, and using a fountain solution and / or ink. It is described that the above can be developed. However, in such a method of forming an image simply by heat coalescence, although good on-press developability is exhibited, there is a problem that printing durability is insufficient due to low image strength.

[0005]

Accordingly, it is an object of the present invention to provide a lithographic printing plate precursor that overcomes the disadvantages of the prior art as described above. That is, it is an object of the present invention to provide a lithographic printing plate precursor having good on-press developability and excellent high printing durability.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above-mentioned object, and as a result, have found that the following constitution can be used to overcome the disadvantages of the prior art. That is, the present invention is as follows. (1) A lithographic plate having an image forming layer containing fine particles containing a phenol resin and at least one selected from the group consisting of an acrylic resin, a urethane resin and an epoxy resin on a hydrophilic support. Original plate for printing plate. (2) The lithographic printing plate precursor as described in (1) above, wherein the fine particles contain a photothermal conversion agent.

The phenol resin contained in the fine particles in the image forming layer of the lithographic printing plate precursor according to the present invention has good adhesion to the substrate, but has poor film quality and poor printing durability.
On the other hand, acrylic resin, urethane resin, epoxy resin, and the like have good film properties and strong film strength, but poor printing durability due to poor adhesion to a substrate. As a result of earnestly examining an image forming layer containing a fine particle polymer capable of achieving both the above-mentioned adhesiveness and film properties and exhibiting excellent printing durability, it was found that the fine particle polymer had the above-described constitution, . The lithographic printing plate precursor according to the invention is subjected to scanning exposure based on digital signals and, when heated, contained in its image forming layer, a phenolic resin and an acrylic resin,
Fine particles containing at least one selected from the group consisting of urethane resins and epoxy resins cause a reaction in a heat mode, so that while exhibiting good on-press developability, the film strength of the heated image area and the substrate And a lithographic printing plate having excellent printing durability can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The lithographic printing plate precursor according to the present invention will be described in detail below. First, the image forming layer, which is a characteristic part of the lithographic printing plate precursor according to the invention, will be described. [Image Forming Layer] The image forming layer (also referred to as a heat-sensitive layer) of the lithographic printing plate precursor according to the invention contains a phenol resin and at least one selected from the group consisting of acrylic resins, urethane resins and epoxy resins. Although it contains fine particles, it can further contain a hydrophilic polymer binder and other additives.

(Phenol resin) Suitable phenol resins include, for example, phenols such as phenol, cresol and xylenol, aldehydes such as formaldehyde, novolak resins or resole resins obtained by condensing with methylol, or resins obtained by polymerizing hydroxystyrene. Can be mentioned. The molecular weight of the phenolic resin of the present invention is preferably 2000 or more on a weight average. The amount of phenol resin added to the fine particles is 2
0% to 90% is preferable, and 30% to 85% is more preferable. If it is less than 20% or more than 90%, the printing durability deteriorates and both are unsuitable.

(Acrylic Resin) The acrylic resin usable in the present invention may be a homopolymer or a copolymer obtained from the following monomers. Specifically, (meth) acrylamide, N-methylol (meth) acrylamide, N-ethylacrylamide, N-hexylacrylamide, N-cyclohexylacrylamide,
N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N
(Meth) acrylamides such as -ethyl-N-phenylacrylamide, methyl (meth) acrylate, (meth)
Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate,
(Substituted) such as hexyl (meth) acrylate, octyl (meth) acrylate, 2-chloroethyl acrylate, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, and cyclohexyl (meth) acrylate Alkyl (meth) acrylates (meth) acrylic acids. The molecular weight of the acrylic resin of the present invention is
Preferably, the weight average is 2,000 or more. The amount of the acrylic resin added to the fine particles is preferably from 10% to 80%, more preferably from 15% to 70%. If it is less than 10% or more than 80%, the printing durability deteriorates and both are unsuitable.

(Epoxy resin) The epoxy resin used in the present invention preferably contains two or more epoxy groups. When there are two or more epoxy groups, crosslinking can be effectively performed, and the effects of the present invention can be easily obtained.

The epoxy resin used in the present invention includes a glycidyl ether compound or a prepolymer thereof obtained by reacting a polyhydric alcohol or polyphenol with epichlorohydrin, and a polymer of acrylic acid or glycidyl methacrylate. Or a copolymer etc. can be mentioned.

Specific examples of suitable compounds include propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether and hydrogenated bisphenol A. Diglycidyl ether, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, diglycidyl ether or epichlorohydrin polyadduct of bisphenol A, diglycidyl ether or epichlorohydrin polyadduct of bisphenol F, and halogenated bisphenol A Diglycidyl ether or epichlorohydrin polyadduct, diglycidyl ether of biphenyl-type bisphenol or Epichlorohydrin adduct, glycidyl ethers of novolac resins, further, methyl methacrylate / glycidyl methacrylate copolymer, methacrylic acid ethyl / glycidyl methacrylate copolymer, and the like.

Commercially available products of the above compounds include, for example, Epicoat 1001 (Molecular weight of about 90
0, epoxy equivalent 450-500), epicoat 1002 (molecular weight about 1600, epoxy equivalent 600-700), epicoat 1004 (molecular weight about 1060, epoxy equivalent 875-975), epicoat 1007
(Molecular weight about 2900, epoxy equivalent 2000), Epicoat 1009
(Molecular weight about 3750, epoxy equivalent 3000), Epicoat 1010
(Molecular weight about 5500, epoxy equivalent 4000), Epicoat 1100
L (Epoxy equivalent 4000), Epicoat YX31575 (Epoxy equivalent 1200), Sumitomo Chemical Co., Ltd. Sumiepoxy ESCN-195XH
N, ESCN-195Xl, ESCN-195XF and the like can be mentioned.
The molecular weight of the epoxy resin of the present invention is preferably 2,000 or more by weight average. The amount of the epoxy resin added to the fine particles is preferably 10% to 80%, more preferably 15% to 70%. If it is less than 10% or more than 80%, the printing durability deteriorates and both are unsuitable.

(Urethane resin) The urethane resin preferably used in the present invention mainly includes a polyurethane resin having a basic skeleton of a reaction product of the following diisocyanate compound (I) and a diol compound. OCN-R ¹ -NCO (I)

In the formula, R ¹ represents a divalent aliphatic or aromatic hydrocarbon which may have a substituent. If necessary, R
^One may have another functional group that does not react with the isocyanate group, for example, an ester, urethane, amide, or ureido group.

Specific examples of the diisocyanate compound represented by the general formula (I) include the following. That is, 2,4-tolylene diisocyanate, dimer of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylylene diisocyanate, m-
Aromatic diisocyanate compounds such as xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate; hexamethylene diisocyanate, trimethylhexamethylene diisocyanate Aliphatic diisocyanate compounds such as lysine diisocyanate and dimer acid diisocyanate; isophorone diisocyanate;
Alicyclic diisocyanate compounds such as 4'-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4 (or 2,6) diisocyanate, 1,3- (isocyanatomethyl) cyclohexane and the like;
Examples thereof include diisocyanate compounds which are reaction products of a diol and a diisocyanate, such as an adduct of 1 mol of 1,3-butylene glycol and 2 mol of tolylene diisocyanate.

The diol compounds specifically include, but are not limited to, the following. 3,5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (2-hydroxyethyl) propionic acid, 2,2-bis (3-hydroxypropyl) propionic acid, bis ( Hydroxymethyl) acetic acid,
Bis (4-hydroxyphenyl) acetic acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid, tartaric acid, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol , Neopentyl glycol, 1,3-butylene glycol, 1,6-hexanediol, 2-butene-1,4-diol, 2,2,
4-trimethyl-1,3-pentanediol, 1,4-
Bis-β-hydroxyethoxycyclohexane, cyclohexanedimethanol, tricyclodecanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, ethylene oxide addition of bisphenol F Propylene oxide adduct of bisphenol F, ethylene oxide adduct of hydrogenated bisphenol A, propylene oxide adduct of hydrogenated bisphenol A, hydroquinone dihydroxyethyl ether, p-xylylene glycol, dihydroxyethyl sulfone, bis (2-hydroxy Ethyl)-
2,4-tolylene dicarbamate, 2,4-tolylene-
Bis (2-hydroxyethylcarbamide), bis (2-
(Hydroxyethyl) -m-xylylenedicarbamate,
Bis (2-hydroxyethyl) isophthalate and the like can be mentioned.

The molecular weight of the urethane resin of the present invention is preferably 2,000 or more on a weight average. The amount of the urethane resin added to the fine particles is preferably 10% to 80%.
% To 70% is more preferable. Less than 10% or 80
%, The printing durability deteriorates and both are unsuitable.

In the present invention, the phenolic resin and at least one selected from the group consisting of an acrylic resin, a urethane resin and an epoxy resin are contained as fine particles in the image forming layer. The fine particles are, for example, a mixture of a phenolic resin and at least one selected from the group consisting of an acrylic resin, a urethane resin and an epoxy resin, dissolved in a water-insoluble organic solvent, and dissolved in an aqueous solution containing a dispersant. And the mixture is emulsified with water, and is further obtained by a solvent evaporation method in which the organic solvent is solidified into fine particles while heating to remove the organic solvent, but is not limited thereto. Further, in the present invention, fine particles in which at least one component such as an infrared absorbing dye and a compound having a functional group which reacts with the fine particle polymer coexist in the fine particles are also suitable. In particular, when the photothermal conversion material described below is contained in the fine particles, image writing can be performed by laser light irradiation or the like. Such fine particles can be obtained by dissolving the phenol resin and at least one selected from the group consisting of acrylic resin, urethane resin and epoxy resin in a water-insoluble organic solvent by the solvent evaporation method. (Infrared absorbing dye) and the like are dissolved together to obtain a solvent evaporation method.

Among the above-mentioned polymer fine particles, those in which the polymer particles are united by heat are preferable, and those whose surface is hydrophilic and which is dispersed in water are particularly preferable. The contact angle (water droplets in the air) of a film produced by applying only the fine particle polymer and drying at a temperature lower than the coagulation temperature is lower than the contact angle of the film produced by drying at a temperature higher than the coagulation temperature ( (Water droplets in the air). In order to make the surface of the fine particle polymer hydrophilic as described above, a hydrophilic polymer or oligomer such as polyvinyl alcohol or polyethylene glycol, or a hydrophilic low-molecular compound may be adsorbed on the surface of the fine particle polymer. However, the present invention is not limited to this.

The solidification temperature of these polymer fine particles is 7
0 ° C. or higher is preferable, but considering the stability over time, 100 ° C.
The above is more preferred. The average particle size of the polymer fine particles is preferably 0.01 to 20 μm, more preferably 0.05 to 2.0 μm, and particularly preferably 0.1 to 20 μm.
1.0 μm is optimal. If the average particle size is too large, the resolution is poor, and if it is too small, the stability over time is deteriorated, so that both the image forming property and the on-press developability can be achieved within the above range of the average particle size.

The amount of the fine particles added to the image forming layer is at least 40% by weight of the solid content of the image forming layer.
% To 95% by weight, more preferably 65% to 90% by weight. If the amount is less than 40% by weight, the image strength deteriorates, and if it is more than 95% by weight, the on-press developability deteriorates.

[Hydrophilic resin] A hydrophilic resin may be added to the image forming layer of the lithographic printing plate precursor according to the invention. The addition of the hydrophilic resin not only improves the on-press developability, but also increases the film strength of the image forming layer (thermosensitive layer) itself. As the hydrophilic resin, those which are not three-dimensionally crosslinked are preferred because of their good on-press developability. As the hydrophilic resin, for example, hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl,
Those having a hydrophilic group such as carboxymethyl are preferred. Specific hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and their Na salts, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids And salts thereof, 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, hydroxy Butyl methacrylate homopolymers and copolymers, hydroxybutyl acrylate homopolymers and copolymers, polyethylene Glycols, hydroxypropylene polymers, polyvinyl alcohols and homopolymers and copolymers of hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight; Examples thereof include methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, and 2-acrylamido-2-methylpropanesulfonic acid and salts thereof homopolymers and copolymers.

The amount of the hydrophilic resin added to the image forming layer is as follows:
It is preferably from 2% to 40%, more preferably from 3% to 30%. If it is less than 2%, the film strength is low, and if it is more than 40%, the on-press developability is improved but the printing durability is deteriorated.

[Light-to-Heat Conversion Material] The lithographic printing plate precursor according to the present invention may contain a light-to-heat conversion material in the fine particles, in an image forming layer containing the fine particles or in a layer adjacent thereto, and further in an overcoat layer described later. , An image can be written by laser light irradiation or the like. The light-to-heat conversion material is not particularly limited as long as it absorbs the wavelength of the light source, such as carbon black / metal fine particles and dye, but a compound that absorbs infrared rays and converts it into heat is particularly preferable.

The photothermal conversion material is particularly preferably a substance that absorbs light of 700 nm or more, and various pigments and dyes can be used. Examples of pigments include commercially available pigment and color index (CI) handbook, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, 1977), “Latest Pigment Application Technology”
(CMC Publishing, 1986), "Printing Ink Technology" C
MC Publishing, 1984) can be used.

Examples of the type of the pigment include a black pigment, a brown pigment, a red pigment, a violet pigment, a blue pigment, a green pigment, a fluorescent pigment, a metal powder pigment, and a polymer-bound pigment. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like.

These pigments may be used without being subjected to a surface treatment, or may be used after being subjected to a surface treatment. Examples of the surface treatment include a method of surface-coating a hydrophilic resin or a lipophilic resin, a method of attaching a surfactant, and a reactive substance (eg, silica sol, alumina sol, a silane coupling agent, an epoxy compound, an isocyanate compound, etc.). A method of binding to the surface of the pigment is conceivable. The above surface treatment methods are described in “Properties and Applications of Metallic Soap” (Koshobo), “Printing Ink Technology”
(CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986).
Among these pigments, those that absorb infrared light or near-infrared light are particularly preferable because they are suitable for use in lasers that emit infrared light or near-infrared light.

As such a pigment absorbing infrared light or near infrared light, carbon black, carbon black coated with a hydrophilic resin, and carbon black modified with silica sol are preferably used. Among these, carbon black whose surface is coated with a hydrophilic resin or silica sol is useful as a material that is easily dispersed in a water-soluble resin and does not impair hydrophilicity.

The particle size of the pigment is preferably in the range of 0.01 μm to 1 μm, and more preferably in the range of 0.01 μm to 0.5 μm. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. As the disperser, an ultrasonic disperser,
Sand mills, attritors, pearl mills, super mills, ball mills, impellers, dispersers, KD mills, colloid mills, dynatrons, three-roll mills, pressure kneaders and the like can be mentioned. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

As the dye, commercially available dyes and known dyes described in literatures (for example, “Dye Handbook” edited by The Society of Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, and cyanine dyes. Among these dyes, those that absorb infrared light or near-infrared light are particularly preferable because they are suitable for use in lasers that emit infrared light or near-infrared light.

Dyes that absorb infrared light or near infrared light include, for example, JP-A-58-125246 and JP-A-59-125246.
No. 84356, JP-A-60-78787, U.S. Pat. No. 4,973,572, JP-A-10-26851
No. 2, etc .;
73696, JP-A-58-181690, JP-A-5-181
Methine dyes described in JP-A-8-194595, JP-A-58-112793, JP-A-58-224793.
JP-A-59-48187, JP-A-59-7399
No. 6, JP-A-60-52940, JP-A-60-637
No. 44, etc .;
Squarylium dyes described in JP-A-8-112792, cyanine dyes described in British Patent No. 434,875, dyes described in U.S. Pat. No. 4,756,993, and U.S. Pat. No. 4,973,572. And the dyes described in JP-A-10-268512.

[0034]

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(Where R¹, R^Two, R^Three, R^Four, R^FiveAnd R⁶
Is a substituted or unsubstituted alkyl group; Z ¹And Z^TwoAlso replace
Or unsubstituted phenyl or naphthalene group; L is substituted
Or an unsubstituted methine group, wherein the substituent has 8 or less carbon atoms
An alkyl group, a halogen atom or an amino group,
The tin group is bonded to the substituents on the two methine carbons
Optionally formed cyclohexene formed by
Or a ring containing a cyclopentene ring
And the substituent is an alkyl group having 6 or less carbon atoms or halogen.
X is an anionic group; n is 1 or 2;¹,
R^Two, R^Three, R^Four, R^Five, R⁶, Z¹And Z^TwoAt least one of
One is an acidic group or an alkali metal base or an amine salt of an acidic group
A substituent having a group is shown. )

[0036]

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(Where R¹¹Is a substituted or unsubstituted al
Killed, substituted or unsubstituted aryl or substituted
Or an unsubstituted heterocyclic group; R¹²And R^FifteenIs a hydrogen atom or
A group which can be substituted in place of a hydrogen atom: R¹³And R¹⁴Is hydrogen field
Atom, halogen atom, substituted or unsubstituted alkoxy group
Or a substituted or unsubstituted alkyl group, provided that R¹³And R
¹⁴Are not simultaneously hydrogen atoms: R¹⁶And R¹⁷Is a replacement
Or unsubstituted alkyl group, substituted or unsubstituted aryl
Group, acyl group or sulfonyl group, or R¹⁶And R ¹⁷In non
The formation of a 5- or 6-membered metal ring is shown. )

Further, as a dye, US Pat. No. 5,156,
No. 938 is also preferably used, and substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924;
No. 42645 (U.S. Pat. No. 4,327,169);
No. 51, No. 58-220143, No. 59-41363
Nos. 59-84248, 59-84249, 59-146063, and 59-146061 and pyrylium compounds described in JP-A-59-2161.
No. 46, a cyanine dye disclosed in U.S. Pat. No. 4,283,4;
No. 75, pentamethine thiopyrylium salt and the like, and pyrilium compounds disclosed in Japanese Patent Publication Nos. 5-135514 and 5-19702, Epolig manufactured by Eporin Co.
ht III-178, Epollight III-130,
Epollight III-125 and the like are particularly preferably used. Particularly preferred among these dyes are the water-soluble cyanine dyes of the above formula (I). Specific compounds are listed below.

[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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Next, the light-heat converting metal fine particles will be described. Many of the metal particles are photothermal and self-heating. Preferred metal fine particles include Si, A
1, Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zn, Y, Zr, Mo, Ag, Au, Pt, Pd, R
Simple particles or alloys of h, In, Sn, W, Te, Pb, Ge, Re, and Sb, or fine particles of oxides and sulfides thereof. Among the metals constituting these metal fine particles, preferred metals are those having a melting point of about 1000 ° C. or less and easily absorbing in the infrared, visible or ultraviolet region, such as Re, Sb, Te, and Au, which are easily fused by light irradiation. , A
g, Cu, Ge, Pb and Sn. Particularly preferred are metal fine particles having a relatively low melting point and a relatively high absorbance to heat rays, such as Ag, Au, Cu, and the like.
Among Sb, Ge and Pb, particularly preferred elements are Ag, A
u and Cu.

Also, for example, Re, Sb, Te, Au, A
g, Cu, Ge, Pb, Sn or other low melting point metal particles and self-heating metal particles such as Ti, Cr, Fe, Co, Ni, W, Ge etc. it may be composed of a material. Ag, P
It is preferable to use a combination of a metal-type micro-piece and a metal-type micro-piece, which have a particularly large light absorption when used as a micro-piece such as t or Pd. The effects of the present invention are more exerted by subjecting the surfaces of the above-described metal simple substance and alloy fine particles to hydrophilic treatment. Means of surface hydrophilicity is a compound that is hydrophilic and has an adsorptivity to particles, for example, surface treatment with a surfactant, or surface treatment with a substance having a hydrophilic group that reacts with the constituent substances of the particles, A method such as providing a protective colloid hydrophilic polymer film can be used. Particularly preferred is a surface silicate treatment. For example, in the case of iron fine particles, sodium silicate (3
%) The surface can be made sufficiently hydrophilic by immersing it in an aqueous solution for 30 seconds. Other metal fine particles can be subjected to a surface silicate treatment in the same manner.

The size of these particles is 10 μm or less, preferably 0.003 to 5 μm, more preferably
0.01 to 3 μm. The finer the particle size, the lower the heat fusing temperature, that is, the higher the light sensitivity in the heat mode, which is advantageous. In the present invention, when these light-to-heat conversion materials are used, the amount added is 1% by weight or more, preferably 2% by weight or more, of the total solid content of the image forming layer (thermosensitive layer) or the overcoat layer described below. ,
Particularly preferably, it is used at 5% by weight or more. If the content of the photothermal conversion material is less than 1% by weight, the sensitivity will be low.

A dye having a large absorption in the visible light region can be used as a colorant for an image. Specifically, Oil Yellow # 101, Oil Yellow # 10
3. Oil pink # 312, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-50
5 (from Orient Chemical Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI4255)
5), methyl violet (CI42535), ethyl violet, rhodamine B (CI145170B),
Malachite green (CI42000), methylene blue (CI52015) and the like, and JP-A-62-29324
No. 7 can be mentioned. Further, pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide can also be suitably used.

It is preferable to add these coloring agents since the image area and the non-image area can be easily distinguished after image formation. The amount of addition is 0.01 to 10% by weight based on the total solid content of the coating solution for the image forming layer.

In the coating solution of the image forming layer in the present invention, in order to widen the stability of processing under development conditions, a non-coating solution such as described in JP-A-62-251740 and JP-A-3-208514 is used. Ionic surfactant, JP-A-5
An amphoteric surfactant as described in JP-A-9-121044 and JP-A-4-13149 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, stearic acid monoglyceride, polyoxyethylene nonyl phenyl ether, and the like.

Specific examples of the amphoteric surfactant include alkyl di (aminoethyl) glycine, alkyl polyaminoethyl glycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, N-tetradecyl-N , N-betaine type (for example,
(Trade name: Amogen K, manufactured by Daiichi Kogyo Co., Ltd.). The proportion of the nonionic surfactant and amphoteric surfactant in the coating solution for the image forming layer is 0.05 to 15% by weight.
Is more preferable, and more preferably 0.1 to 5% by weight.

In order to produce the lithographic printing plate precursor according to the invention, the above-mentioned components necessary for the coating solution for the image forming layer are usually dissolved in a solvent and applied onto a suitable support. As the solvent used here, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-
2-propanol, 2-methoxyethyl acetate, 1
-Methoxy-2-propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyllactone, Water and the like can be mentioned, but it is not limited thereto. These solvents are used alone or as a mixture. The concentration of the above components (total solids including additives) in the solvent is preferably 1 to 5
0% by weight.

The coating amount (solid content) of the image forming layer on the support obtained after coating and drying varies depending on the application.
Speaking of lithographic printing plate precursors, generally 0.5 to 5.
0 g / m ² is preferred. Various methods can be used as the method of coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. As the application amount decreases,
Although the apparent sensitivity is increased, the film characteristics of the image forming layer that performs the function of image recording are reduced.

In the coating solution for the image forming layer according to the present invention, a surfactant for improving coating properties, for example, a surfactant described in
A fluorinated surfactant as described in No. 170950 can be added. The preferred addition amount is 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight, based on the solid content of the material of the entire image forming layer.

[Overcoat Layer] In the lithographic printing plate precursor according to the present invention, a water-soluble overcoat layer can be provided on the image forming layer in order to prevent contamination of the surface of the image forming layer by a lipophilic substance. The water-soluble overcoat layer used in the present invention can be easily removed at the time of printing and contains a resin selected from water-soluble organic polymer compounds. As the water-soluble organic polymer compound used here, a film formed by coating and drying has a film forming ability,
Specifically, polyvinyl alcohol, polyvinyl acetate (having a hydrolysis rate of 65% or more), polyacrylic acid and its alkali metal salt or amine salt, polyacrylic acid copolymer and its alkali metal salt or amine salt, Polymethacrylic acid and its alkali metal salt or amine salt, polymethacrylic acid copolymer and its alkali metal salt or amine salt, polyacrylamide and its copolymer, polyhydroxyethyl acrylate, polyvinylpyrrolidone and its copolymer, polyvinylmethyl Ether, polyvinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl-1
-Propanesulfonic acid and its alkali metal salts or amine salts, poly-2-acrylamido-2-methyl-1-
Propanesulfonic acid copolymer and its alkali metal salt or amine salt, gum arabic, cellulose derivatives (for example, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, white dextrin, pullulan, enzymatic etherification Dextrin and the like can be mentioned. Further, according to the purpose, two or more of these resins can be used in combination. Among these water-soluble resins, gum arabic is most preferred from the viewpoint of on-press developability.

(Fluorine atom-containing compound or silicon atom-containing compound) The water-soluble overcoat layer of the lithographic printing plate precursor according to the present invention contains a releasing agent to prevent sticking between the plates during stacking and storage. It is preferred to contain a fluorine atom-containing compound or a silicon atom-containing compound having the following formula. As the fluorine compound, a water-soluble or water-dispersible fluorine-based surfactant is used. Specifically, F
Substituted dodecanoic acid, F-substituted octanoic acid, F-substituted hexanoic acid, F-substituted butyric acid, ammonium salts of these carboxylic acids,
Examples include compounds having a perfluoroalkyl group and an ethyleneoxy group in the same molecule. As the silicon atom-containing compound, a water-soluble or water-dispersible silicone oil is used. Specific examples include polyether-modified silicone oil. The proportion of these compounds in the total solid content of the overcoat layer is 0.05 to 5.
It is preferably 0% by weight, more preferably 0.1% to 3% by weight. If the content is less than 0.05%, the lithographic printing plate precursors are easily adhered to each other when stacked, and the plate is scratched when rubbed with an aluminum piece, and scratches and stains are likely to occur. If the content is more than 5% by weight, the developability of the overcoat layer will deteriorate and the waste paper will increase.

The overcoat layer preferably contains a water-soluble photothermal conversion agent described below. Furthermore, in the case of aqueous solution application, a nonionic surfactant such as polyoxyethylene nonylphenyl ether and polyoxyethylene dodecyl ether can be added to the overcoat layer in order to ensure uniformity of application. . Dry coating amount of the overcoat layer, 0.1 to 2.0 g / m ² is preferred. When the amount is less than that, it causes the fingerprint smudges,
If it is more than that, the on-press developability deteriorates.

[Support] In the lithographic printing plate precursor of the present invention, the hydrophilic support to which the heat-sensitive layer can be applied is a dimensionally stable plate-like material such as paper or plastic (for example, Paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate) on which polyethylene, polypropylene, polystyrene, etc. are laminated;
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 vapor-deposited. Preferred supports include a polyester film or an aluminum plate.

As the support used in the lithographic printing plate precursor of the present invention, it is preferable to use an aluminum plate which is lightweight and has excellent surface treatment properties, workability and corrosion resistance. Aluminum materials used for this purpose include JIS 105
0 material, JIS 1100 material, JIS 1070 material, Al
-Mg-based alloy, Al-Mn-based alloy, Al-Mn-Mg-based alloy, Al-Zr-based alloy, Al-Mg-Si-based alloy and the like.

Known techniques relating to aluminum materials that can be used for the support are listed below. (1) The following technology is disclosed for JIS 1050 material. JP-A-59-153861;
1-51395, JP-A-62-146694, JP-A-6-146694
0-215725, JP-A-60-215726, JP-A-60-215727, JP-A-60-215728, JP-A-61-272357, JP-A-58-11759, JP-A-58-42493, JP-A-58 -212254, JP-A-62-148295, JP-A-4-254545, JP-A-4-165541, JP-B-3-68939, JP-A-3-6899
234,594, Japanese Patent Publication No. 47475, JP-A-62-
140894 and the like. In addition, Tokuhei 1-3591
0, Japanese Patent Publication No. 55-28874 and the like are also known.

(2) With respect to JIS 1070 material, the following technology is disclosed. JP-A-7-81264, JP-A-7-305133, JP-A-8-49034, JP-A-8-73974, JP-A-8-108657, JP-A-8-108
92679 etc.

(3) With respect to Al-Mg based alloys, the following techniques are disclosed. JP-B-62-5080, JP-B-63-60823, JP fairness 3-61753, JP-A-6
0-203496, JP-A-60-203497, JP-B-3-11635, JP-A-61-274993, JP-A-62-14973.
2-237794, JP-A-63-47347, JP-A-63-63
-47348, JP-A-63-47349, JP-A-64-
61293, JP-A-63-135294, JP-A-63-135
87288, JP 4-73392, JP 7-100
844, JP-A-62-149856, JP-B-4-733
94, JP-A-62-181191, Japanese Patent Publication No. 5-7653
0, JP-A-63-30294 and JP-B-6-37116. Further, JP-A-2-215599, JP-A-61-2
No. 01747 is also known.

(4) With respect to Al-Mn alloys, the following techniques are disclosed. JP-A-60-230951,
JP-A-1-306288 and JP-A-2-293189. In addition, Japanese Patent Publication No. 54-42284, Japanese Patent Publication No. 4-192
90, Japanese Patent Publication 4-19291, Japanese Patent Publication 4-19292,
JP-A-61-35995, JP-A-64-51992, U
S5009722, US5028276, JP-A-4-4-2
26394 and the like are also known. (5) With respect to Al-Mn-Mg based alloys, the following technology is disclosed. JP-A-62-86143, JP-A-Hei 3
-22,796, JP-B-63-60824, JP-A-Showa 60
-63346, JP-A-60-63347, EP2237
37, JP-A-1-283350, US4818300,
BR1222777 and the like are known.

(6) With respect to Al-Zr alloys, the following techniques are known. JP-B-63-15978, JP-A-61-51395, JP-A-63-143234 and JP-A-63-143235 are known. (7) For the Al-Mg-Si alloy, BR142
1710 and the like are known.

The following contents can be used as a method for producing an aluminum plate for a support. The aluminum alloy melt having the above-mentioned content components and alloy component ratios is subjected to a cleaning treatment and cast according to a conventional method. For the cleaning process,
In order to remove unnecessary gases such as hydrogen in the molten metal, flux processing, degassing processing using Ar gas, Cl gas, etc., so-called rigid media filters such as ceramic tube filters and ceramic foam filters,
Filtering using a filter material such as alumina flakes or alumina balls, filtering using a glass cloth filter or the like, or processing combining degassing and filtering is performed. These cleaning processes are performed in the molten metal.
It is desirable to carry out the method in order to prevent defects due to foreign substances such as nonmetallic inclusions and oxides and defects due to gas dissolved in the molten metal.

Regarding the filtering of molten metal, Japanese Patent Application Laid-Open Nos. Hei 6-57342, Hei 3-162530, Hei 5
140659, JP-A-4-231425, JP-A-4-2
76031, JP-A-5-311261, JP-A-6-13
6466 and the like are known. Regarding degassing of molten metal,
JP-A-5-51659, JP-A-5-51660, JP-A-5-49148, and JP-A-7-40017 are known. As described above, casting is performed using the molten metal subjected to the cleaning treatment. Regarding the casting method, there are a method using a fixed mold typified by a DC casting method and a method using a driving mold typified by a continuous casting method. When the DC casting method is used, the solidification is performed at a cooling rate of 1 to 300 ° C./sec. If it is lower than 1 ° C./sec, a large number of coarse intermetallic compounds are formed.

The continuous casting method includes a method using a cooling roll, represented by the Hunter method and the 3C method, a Hadley method, a method using a cooling belt represented by the Al Swiss Caster II type, and a method using a cooling block. It is being done. The cooling rate when using the continuous casting method is 100 to 1000 ° C. /
Coagulated in seconds. Generally, since the cooling rate is higher than that of the DC casting method, there is a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. Regarding the continuous casting method, the inventors of the present invention disclosed in Japanese Patent Laid-Open No.
9798, JP-A-5-201166, JP-A-5-156
414, JP-A-6-262203, JP-A-6-1229
49, JP-A-6-210406, JP-A-6-26230
8 etc. are disclosed.

When DC casting is performed, the thickness is 300 to 80.
A 0 mm ingot can be produced. The ingot, according to the usual method,
Facing is performed and the surface layer is 1 to 30 mm, preferably 1 to 30 mm
10 mm is cut. Thereafter, a soaking process is performed as necessary. In the case of performing the soaking treatment, 1 to 450 ° C. to 620 ° C. is performed so that the intermetallic compound is not coarsened.
The heat treatment is performed for at least 48 hours. When the time is shorter than 1 hour, the effect of the soaking treatment becomes insufficient. Next, hot rolling and cold rolling are performed to obtain a rolled aluminum plate. The starting temperature of hot rolling is 350 to 500
It is in the range of ° C. An intermediate annealing treatment may be performed before, after, or during the cold rolling. The intermediate annealing conditions in this case are set to 280 ° C. to 6 ° C. using a batch annealing furnace.
00 ° C for 2 to 20 hours, desirably 350 to 500 ° C
For 2 to 10 hours, or using a continuous annealing furnace for 4 hours.
360 seconds or less at 00 to 600 ° C., desirably 450 to
Heat treatment at 550 ° C. for 120 seconds or less can be employed. Heating at a rate of 10 ° C./sec or higher using a continuous annealing furnace can also make the crystal structure fine.

By the above steps, a predetermined thickness of 0.1 to 0.1
The flatness of the Al plate finished to 0.5 mm may be improved by a straightening device such as a roller leveler or a tension leveler in order to improve the flatness. The flatness may be improved after the plate is cut into a sheet. However, in order to improve productivity, it is desirable to improve the flatness in a continuous coil state. Further, in order to process the plate width to a predetermined width, it is usually performed to pass through a slitter line. The end face of the plate cut by the slitter has one or both of a shear surface and a fracture surface when cut by a slitter blade.

The accuracy of the thickness of the plate is preferably within ± 10 μm, preferably within ± 6 μm over the entire length of the coil.
The thickness difference in the width direction is within 6 μm, preferably 3 μm.
Within is good. Also, the accuracy of the board width is within ± 1.0mm,
Preferably, it is within ± 0.5 mm. Although the surface roughness of the Al plate is easily affected by the surface roughness of the rolling roll,
Finally, the center line surface roughness (Ra) is Ra = 0.1 to
It is preferable to finish to about 1.0 μm. If Ra is too large, the original roughness of Al, that is, the rough rolling streaks transferred by the rolling rolls can be seen from above the heat-sensitive layer when the surface-roughening treatment for a lithographic printing plate and the heat-sensitive layer are applied. Is not preferable in appearance. Roughness of Ra = 0.1 μm or less is industrially undesirable because the surface of the rolling roll needs to be finished to an excessively low roughness.

Further, a thin oil film may be formed on the surface of the Al plate in order to prevent scratches due to friction between the Al plates. Oil slicks may be volatile,
A non-volatile one is appropriately used. If there is too much oil,
A slip failure occurs in the production line, but if there is no oil amount, a defect occurs during transportation of the coil. Therefore, the oil amount is 3 mg / m ² or more and 100 mg / m ² or less, and a desirable upper limit is 50 mg / m ^2. m ² or less, more preferably 10
mg / m ² or less is good. Regarding cold rolling,
No. -210308 is disclosed.

When continuous casting is performed, for example, using a cooling roll such as a Hunter method can directly and continuously cast and roll a cast plate having a thickness of 1 to 10 mm, and has the advantage of omitting the hot rolling step. In addition, when a cooling roll such as the Hasley method is used, a cast plate having a plate thickness of 10 to 50 mm can be cast,
Generally, a hot-rolled roll is arranged immediately after casting and continuously rolled to obtain a continuously cast rolled plate having a thickness of 1 to 10 mm. These continuous cast rolled sheets are finished to a thickness of 0.1 to 0.5 mm through the steps of cold rolling, intermediate annealing, improvement of flatness, slits, etc., as described in the case of DC casting. Can be Regarding the intermediate annealing conditions and the cold rolling conditions when using the continuous casting method, see JP-A-6-2205.
93, JP-A-6-210308, JP-A-7-5411
1, JP-A-8-92709 and the like are disclosed.

The surface of the Al plate manufactured by the above method is subjected to a surface treatment such as a surface roughening treatment, and a heat-sensitive layer is applied thereon to obtain a lithographic printing plate precursor. In the surface roughening treatment, mechanical surface roughening, chemical surface roughening, and electrochemical surface roughening are performed alone or in combination. Further, it is also preferable to perform an anodic oxidation treatment for ensuring the surface is hardly scratched or a treatment for increasing the hydrophilicity.

The surface treatment of the support will be described below. Prior to roughening the aluminum plate, if necessary, for example, a surfactant for removing rolling oil on the surface,
A degreasing treatment with an organic solvent or an alkaline aqueous solution may be performed. In the case of alkali, treatment such as neutralization and removal of smut may be performed with an acidic solution.

Next, in order to improve the adhesion between the support and the heat-sensitive layer and to impart water retention to the non-image area, a so-called graining treatment is performed to roughen the surface of the support. Specific means of the graining method include sand blast, ball grain, wire grain, brush grain using a nylon brush and an abrasive / water slurry,
There is a mechanical graining method using a honing grain or the like in which an abrasive / water slurry is sprayed on the surface at a high pressure, and a chemical graining method in which the surface is roughened with an etching agent composed of an alkali, an acid, or a mixture thereof. . In addition, British Patent No. 896,563,
JP-A-3-67507, JP-A-54-146234 and JP-B-48-28123 describe the method of electrochemical graining, or JP-A-53-1232.
No. 04, JP-A-54-63902, a method combining the mechanical graining method and the electrochemical graining method, and the mechanical graining method described in JP-A-56-55261. There is also known a method in which a graining method is combined with a chemical graining method using a saturated aqueous solution of an aluminum salt of a mineral acid. Also, a method of roughening the surface by adhering the granular material to the support material with an adhesive or a method having the effect thereof, or by pressing a continuous band or roll having fine unevenness on the support material to reduce the unevenness. A rough surface may be formed by transferring.

A plurality of such surface roughening methods may be performed in combination, and the order, the number of repetitions, and the like can be arbitrarily selected. When a plurality of surface roughening treatments are combined, a chemical treatment with an acid or alkali aqueous solution can be performed during that time so that the subsequent surface roughening treatment can be performed uniformly. Specific examples of the above-mentioned acid or alkali aqueous solution include, for example, acids such as hydrofluoric acid, fluorinated zirconic acid, phosphoric acid, sulfuric acid, hydrochloric acid, and nitric acid, and alkali aqueous solutions such as sodium hydroxide, sodium silicate, and sodium carbonate. . These acid or alkali aqueous solutions can be used alone or in combination of two or more. The chemical treatment uses a 0.05 to 40% by weight aqueous solution of these acids or alkalis,
In general, the treatment is performed at a liquid temperature of 00 ° C. for 5 to 300 seconds.

Since a smut is formed on the surface of the support obtained by the above-described roughening treatment, ie, graining treatment, a treatment such as washing with water or alkali etching is appropriately performed to remove the smut. Is generally preferred. Examples of such processing include, for example,
Examples of the treatment method include an alkali etching method described in JP-A-8-28123 and a desmutting method described in JP-A-53-12739. In the case of the aluminum support used in the present invention, after the pretreatment as described above, usually, in order to improve abrasion resistance, chemical resistance, and water retention, an oxide film is formed on the support by anodic oxidation. Is formed.

As the electrolyte used for the anodic oxidation treatment of the aluminum plate, any electrolyte that forms a porous oxide film can be used.
Phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte. Since the treatment conditions of anodization vary depending on the electrolyte used, it cannot be specified unconditionally.
It is appropriate that the current density is 5 to 60 A / dm ² , the voltage is 1 to 100 V, and the electrolysis time is 10 seconds to 5 minutes. The amount of the anodized film is suitably 1.0 g / m ² or more, but more preferably in the range of 2.0 to 6.0 g / m ^2. When the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient or the non-image area of the lithographic printing plate is easily damaged, and the ink adheres to the damaged area during printing. "Scratch dirt" is likely to occur.

The anodic oxidation treatment is performed on the surface of the lithographic printing plate support used for printing, and the back surface of the electric force lines causes the back surface of the lithographic printing plate to have an anodic oxidation rate of 0.01 to 3 g / m ² . Generally, an oxide film is formed. In addition, an anodic oxidation treatment in an alkaline aqueous solution (for example, a caustic soda aqueous solution of several%) or a molten salt, or an anodic oxidation treatment for forming a nonporous anodic oxide film using, for example, an ammonium borate aqueous solution can be performed. . Before performing anodizing treatment,
A hydrated oxide film described in JP-A-148991 or JP-A-4-97896 may be formed, and a metal silicate described in JP-A-63-56497 or JP-A-63-67295 may be used. An acid salt solution, a hydrated oxide film forming treatment, a chemical conversion film forming treatment described in JP-A-56-144195, and the like can also be performed.

The aluminum support used in the lithographic printing plate precursor according to the present invention can be treated with an organic acid or a salt thereof after anodizing treatment, or the organic acid or a salt thereof can be used as an undercoat layer applied to a heat-sensitive layer. . Examples of the organic acid or a salt thereof include an organic carboxylic acid, an organic phosphonic acid, an organic sulfonic acid or a salt thereof, and preferably an organic carboxylic acid or a salt thereof. Examples of the organic carboxylic acids include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lauric acid, palmitic acid, and stearic acid; unsaturated aliphatic monocarboxylic acids such as oleic acid and linoleic acid; oxalic acid, succinic acid Aliphatic dicarboxylic acids such as acid, adipic acid, and maleic acid; oxycarboxylic acids such as lactic acid, gluconic acid, malic acid, tartaric acid, and citric acid; aromatic carboxylic acids such as benzoic acid, mandelic acid, salicylic acid, and phthalic acid; , IIb, IIIb, IVa, VI
Group b and VIII metal salts and ammonium salts. Preferred among the organic carboxylate salts are formic acid,
Acetic acid, butyric acid, propionic acid, lauric acid, oleic acid,
The above-mentioned metal salts and ammonium salts of succinic acid and benzoic acid. These compounds may be used alone or in combination of two or more.

These compounds are used in water and alcohol in 0.0
It is preferably dissolved in a concentration of from 0.01 to 10% by weight, particularly from 0.01 to 1.0% by weight. The processing conditions include a temperature range of 25 to 95 ° C, preferably 50 to 95 ° C.
H is 1 to 13, preferably 2 to 10 minutes, 10 seconds to 20
The support is immersed for 10 minutes, preferably 10 seconds to 3 minutes, or the treatment liquid is applied to the support.

[0085] Further, it is possible to further after the anodic oxidation treatment, and treatment with compound solution as follows, these compounds, used as a subbing layer of the image forming layer coating. Suitable compounds include, for example, organic phosphonic acids such as phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid which may have a substituent, Phenylphosphoric acid which may have a group, organic phosphoric acid such as naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid, phenylphosphinic acid which may have a substituent,
Organic phosphinic acids such as naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, glycine, β-alanine, valine, serine, threonine, aspartic acid, glutamic acid, arginine, lysine, tryptophan, parahydroxyphenylglycine, dihydroxyethylglycine, anthranil amino acid such as an acid;
Aminosulfonic acids such as sulfamic acid and cyclohexylsulfamic acid; 1-aminomethylphosphonic acid, 1-dimethylaminoethylphosphonic acid, 2-aminoethylphosphonic acid, 2-aminopropylphosphonic acid, 4-aminophenylphosphonic acid, 1-aminoethane -1,1-diphosphonic acid, 1-amino-1-phenylmethane-1,1-diphosphonic acid, 1-dimethylaminoethane-1,1-diphosphonic acid, 1-dimethylaminobutane-1,1-diphosphonic acid, Examples include compounds such as aminophosphonic acid such as ethylenediaminetetramethylenephosphonic acid.

In addition, hydrochloric acid, sulfuric acid, nitric acid, sulfonic acid (such as methanesulfonic acid) or oxalic acid, and an alkali metal,
Salts with ammonia, lower alkanolamines (such as triethanolamine), lower alkylamines (such as triethylamine) and the like can also be suitably used.

Polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneimine and its mineral salts, poly (meth) acrylic acid and its metal salts, polystyrenesulfonic acid and its metal salts, alkyl (meth) acrylate and 2-acrylamide Water-soluble polymers such as 2-methyl-1-propanesulfonic acid and its metal salts, polymers of trialkylammonium methylstyrene and its copolymers with (meth) acrylic acid, and polyvinylphosphonic acid can also be used preferably. it can. Further, soluble starch, carboxymethylcellulose, dextrin, hydroxyethylcellulose, gum arabic, guar gum, sodium alginate, gelatin, glucose, sorbitol and the like can also be suitably used. These compounds may be used alone or in combination of two or more.

In the case of treatment, these compounds are preferably dissolved in water and / or methyl alcohol at a concentration of 0.001 to 10% by weight, particularly 0.01 to 1.0% by weight. The temperature is in the range of 25 to 95 ° C., preferably 50 to 95 ° C., and the pH is 1 to 13, preferably 2 to 10, 10 seconds to 20 minutes, and preferably 10 seconds to 3 minutes.

When used as an undercoat layer applied to the image forming layer (thermosensitive layer), the concentration of the same in water and / or methyl alcohol is 0.001 to 10% by weight, particularly 0.01 to 1.0% by weight. It can be used in the pH range of 1 to 12, if necessary, by adjusting the pH with a basic substance such as ammonia, triethylamine or potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid. Further, a yellow dye can be added for improving the tone reproducibility of the lithographic printing plate precursor. The coating amount of the organic undercoat layer after drying is suitably from ² to 200 mg / m ² , and preferably from 5 to 100 mg / m ² . The above coating amount is 2mg
If it is less than / m ² , a sufficient effect for the original purpose such as prevention of stain cannot be obtained. On the other hand, if it exceeds 200 mg / m ² , the printing durability will decrease.

An intermediate layer for improving the adhesion between the support and the image forming layer may be provided. In order to improve the adhesion, the intermediate layer is generally made of a diazo resin or a phosphoric acid compound adsorbed on aluminum, for example. The thickness of the intermediate layer is arbitrary and must be such a thickness that a uniform bond-forming reaction with the upper thermosensitive layer can be performed when exposed. Usually, a dry solid has a good coating ratio of about 1 to 100 mg / m ² , and 5 to 40 mg / m ² is particularly good. The usage ratio of the diazo resin in the intermediate layer is 30 to 100%, preferably 60 to 100%.

Before the above treatment and the application of the undercoat layer, the support subjected to the anodic oxidation treatment is washed with water, and then the dissolution of the anodic oxide film in the developing solution or dampening solution is suppressed, and the components of the heat-sensitive layer are removed. The following treatments can be performed for the purpose of suppressing residual film, improving the strength of the anodic oxide film, improving the hydrophilicity of the anodic oxide film, improving the adhesion to the heat-sensitive layer, and the like. One of them is a silicate treatment in which the anodic oxide film is brought into contact with an aqueous solution of an alkali metal silicate for treatment. In this case, the concentration of the alkali metal silicate is 0.1 to 30% by weight, preferably 0.5 to 15% by weight, and the pH at 25 ° C is 10 to 13.5. , Preferably 10 to 70 ° C, more preferably 15 to 50 ° C for 0.5 to 120 seconds. The contacting method may be any method such as dipping or spraying. The alkali metal silicate aqueous solution is p
When H is lower than 10, the liquid gels, and when H is higher than 13.5, the anodic oxide film is dissolved.

As the alkali metal silicate used in the present invention, sodium silicate, potassium silicate, lithium silicate and the like are used. P of aqueous alkali metal silicate solution
Hydroxides used for H adjustment include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. In addition, alkaline earth metal salts or IVb
A group metal salt may be blended. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate and barium nitrate, and water-soluble salts such as sulfate, hydrochloride, phosphate, acetate, oxalate and borate. Is mentioned. Group IVb metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, and the like. The alkaline earth metal or Group IVb metal salt can be used alone or in combination of two or more. The preferred range of these metal salts is 0.01 to 10% by weight, and more preferably 0.05 to 5.0% by weight.

In addition, various sealing treatments can be mentioned, and steam sealing, boiling water (hot water) sealing, and metal salt sealing (generally known as methods for sealing an anodic oxide film) are also available. Chromate / dichromate seal, nickel acetate seal, etc.), oil impregnated seal, synthetic resin seal, low temperature seal (by red blood salt or alkaline earth salt, etc.) can be used. , Performance as a support for a printing plate (adhesion with a heat-sensitive layer and hydrophilicity),
From the viewpoints of high-speed processing, low cost, and low pollution, steam sealing is relatively preferred. As the method, for example,
No. 176690 discloses a method of continuously or discontinuously applying pressurized or normal pressure steam to an anodized film at a relative humidity of 70% or more and a steam temperature of 95 ° C. or more for about 2 to 180 seconds. And the like. As another sealing treatment method, a method of immersing or spraying the support in hot water or an alkaline aqueous solution at about 80 to 100 ° C.,
Alternatively or subsequently, it can be dipped or sprayed with a nitrous acid solution. Examples of nitrites are Ia, IIa, IIb, IIIb, IVb, IVa, VI of the periodic table.
a, VIIa, and VIII metal nitrites or ammonium salts, ie, ammonium nitrite, such as LiO ₂ , NaNO ₂ , KNO ₂ , MNO;
g (NO ₂ ) ₂ , Ca (NO ₂ ) ₂ , Zn (NO ₃ ) ₂ , Al
(NO ₂ ) ₃ , Zr (NO ₂ ) ₄ , Sn (NO ₂ ) ₃ , Cr
(NO ₂ ) ₃ , Co (NO ₂ ) ₂ , Mn (NO ₂ ) ₂ , Ni
(NO ₂ ) _{2 and the} like are preferable, and alkali metal nitrite is particularly preferable. Two or more nitrites can be used in combination.

The processing conditions cannot be uniquely determined because they vary depending on the state of the support and the type of alkali metal.
For example, when sodium nitrite is used, the concentration is generally 0.001 to 10% by weight, more preferably 0.01 to 10% by weight.
1-2% by weight, bath temperature generally from room temperature to about 100 ° C
Before and after, more preferably at 60 to 90 ° C., and the treatment time may be generally selected from the respective ranges of 15 to 300 seconds, more preferably 10 to 180 seconds. Nitrous acid aqueous solution
H is preferably adjusted to 8.0 to 11.0, and particularly preferably adjusted to 8.5 to 9.5. To adjust the pH of the nitrous acid aqueous solution to the above range,
For example, it can be suitably prepared using an alkaline buffer or the like. Examples of the alkaline buffer include, but are not limited to, a mixed aqueous solution of sodium hydrogen carbonate and sodium hydroxide, a mixed aqueous solution of sodium carbonate and sodium hydroxide, a mixed aqueous solution of sodium carbonate and sodium hydrogen carbonate, and a mixed aqueous solution of sodium chloride and sodium hydroxide. Mixed aqueous solution,
A mixed aqueous solution of hydrochloric acid and sodium carbonate, a mixed aqueous solution of sodium tetraborate and sodium hydroxide, and the like can be suitably used. Further, as the alkaline buffer, an alkali metal salt other than sodium, for example, a potassium salt can be used.

After performing the silicate treatment or the sealing treatment as described above, in order to improve the adhesion to the image forming layer, an acidic aqueous solution treatment and a hydrophilic undercoating disclosed in JP-A-5-278362 are used. Or an organic layer disclosed in JP-A-4-282637 or JP-A-7-314937 may be provided.

After the above-mentioned treatment or undercoating is applied to the surface of the support, a back coat is provided on the back surface of the support, if necessary. As such a back coat, a coating layer comprising a metal oxide obtained by hydrolyzing and polycondensing an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174 is used. It is preferably used. Among these coating layers, Si (OCH ₃ ) ₄ and Si (OC
_{2 H 5) 4, Si (} OC 3 H 7) 4, Si (OC 4 H 9) is easily available and inexpensive alkoxy compounds of silicon such as _4, the coating layer of the obtained therefrom metal oxide in developing solution Excellent and particularly preferred.

The preferred characteristics of the lithographic printing plate support are center line average roughness of 0.10 to 1.2 μm. When the thickness is less than 0.10 μm, the adhesion to the heat-sensitive layer decreases,
Significant reduction in printing durability occurs. If it is larger than 1.2 μm, the stain property at the time of printing deteriorates. Further, the color density of the support is 0.15 to 0.5 as a reflection density value.
65, and when it is whiter than 0.15, the halation at the time of image exposure is too strong and hinders image formation,
If it is less than 0.65, the image is difficult to see in the plate inspection work after development, and the plate inspection is extremely poor.

In the lithographic printing plate precursor of the present invention, better on-press developability can be obtained by using an aluminum substrate which has been subjected to a surface roughening treatment and then anodized as a support. be able to. In that case, it is more preferable to use an aluminum substrate further subjected to a silicate treatment.

This printing plate is made of a hydrophilic layer insoluble in water on an aluminum substrate, a hydrophilic layer insoluble in water and heated by laser exposure, or an organic polymer for imparting heat insulation to the aluminum substrate. In addition to the heat insulating layer, a hydrophilic layer insoluble in water or a hydrophilic layer that generates heat by laser exposure and is insoluble in water may be provided. For example, a hydrophilic layer of silica fine particles and a hydrophilic resin may be provided on an aluminum substrate. Further, the above-described photothermal conversion material may be introduced into the hydrophilic layer to form a heat-generating hydrophilic layer. This makes it difficult for heat to escape to the aluminum substrate, or the aluminum substrate can be used as a hydrophilic substrate that generates heat by laser exposure. Further, when an intermediate layer made of an organic polymer is provided between the hydrophilic layer and the aluminum substrate, the escape of heat to the aluminum substrate can be further suppressed. The support is preferably non-porous from the viewpoint of on-press developability, and a support that swells with water containing 40% or more of a hydrophilic organic polymer material is difficult to be dispensed with ink. turn into.

The hydrophilic layer used in the present invention is three-dimensionally cross-linked, is a layer which is insoluble in soaking water in lithographic printing using water and / or ink, and preferably comprises the following colloids. It is a colloid comprising a sol-gel conversion system of an oxide or hydroxide of beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony or a transition metal. In some cases, a colloid comprising a complex of these elements may be used. These colloids have a structure in which the above elements form a network structure via an oxygen atom and have an unbonded hydroxyl group or alkoxy group at the same time, and these are mixed. From the initial hydrolysis-condensation stage, which is rich in active alkoxy groups and hydroxyl groups, the particle size increases and becomes inactive as the reaction proceeds. Colloidal particles generally have a diameter of 2 nm to 500 nm, and in the case of silica, spherical particles having a diameter of 5 nm to 100 nm are suitable in the present invention. 100 × 10n like aluminum colloid
A feather-like material such as m is also effective. Furthermore, 10n
A pearl neck-shaped colloid in which spherical particles of m to 50 nm are connected in a length of 50 to 400 nm can also be used.

The colloid may be used alone,
Furthermore, it is also possible to mix and use with a hydrophilic resin. Further, a colloidal crosslinking agent may be added to promote crosslinking. Usually, colloids are often stabilized by stabilizers. In a colloid charged with a cation, a compound having an anionic group is added as a stabilizer, and in a colloid charged with an anion, a compound having a cationic group is added as a stabilizer. For example, a silicon colloid is charged with an anion, so an amine compound is added as a stabilizer, and an aluminum colloid is charged with a cation, so a strong acid such as hydrochloric acid or acetic acid is added. When such a colloid is applied on a substrate, it often forms a transparent film at room temperature, but gelation is incomplete by evaporating the solvent of the colloid, and by heating to a temperature at which the stabilizer can be removed by heating By performing strong tertiary cross-linking, it becomes a hydrophilic layer preferable in the present invention.

[0102] Without using the above-mentioned stabilizing agent, a hydrolysis and condensation reaction is directly carried out from a starting material (for example, di, tri and / or tetraalkoxy silane) to form an appropriate sol state and directly onto a substrate. The reaction may be completed by coating and drying. In this case, three-dimensional crosslinking can be performed at a lower temperature than when a stabilizer is included.

In addition, a colloid obtained by dispersing and stabilizing an appropriate hydrolysis-condensation reaction product in an organic solvent is also suitable for the present invention. Only by evaporation of the solvent, a three-dimensionally crosslinked film is obtained. If these solvents are low boiling solvents such as methanol, ethanol, propanol, butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and methyl ethyl ketone,
Drying at normal temperature becomes possible. In particular, in the present invention, the colloid of a methanol or ethanol solvent is useful because it can be easily cured at a low temperature.

As the hydrophilic resin used together with the above colloid, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl and carboxymethyl are preferred. Specific hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and their Na salts, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids And salts thereof, polymethacrylic acids and salts thereof, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers,
Hydroxypropyl acrylate homopolymers and copolymers, hydroxybutyl methacrylate homopolymers and copolymers, hydroxybutyl acrylate homopolymers and copolymers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and a degree of hydrolysis of at least 60% by weight; Preferably at least 80% by weight of hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, homopolymers and copolymers of acrylamide, homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, 2-acrylamide- 2
And homopolymers and copolymers of methylpropanesulfonic acid or a salt thereof.

Particularly preferred hydrophilic resins are non-water-soluble polymers containing hydroxyl groups, specifically, homopolymers and copolymers of hydroxyethyl methacrylate and copolymers of hydroxyethyl acrylate. These hydrophilic resins are used together with a colloid, but the addition ratio is 40% of the total solid content of the hydrophilic layer when the hydrophilic resin is water-soluble.
% By weight or less, and in the case of a hydrophilic resin which is not water-soluble, preferably 20% by weight or less of the total solid content.

These hydrophilic resins can be used as they are, but a crosslinking agent of a hydrophilic resin other than colloid may be added for the purpose of increasing the printing durability during printing. Formaldehyde, crosslinker of such a hydrophilic resin,
Examples include initial hydrolysis and condensation products of glioxal, polyisocyanate and tetraalkoxysilane, dimethylol urea and hexamethylol melamine. In addition to the above-mentioned colloid of the oxide or hydroxide and the hydrophilic resin, a crosslinking agent which promotes the crosslinking of the colloid may be added to the hydrophilic layer of the present invention. As such a crosslinking agent, an initial hydrolysis condensate of tetraalkoxysilane, trialkoxysilylpropyl-N, N, N-trialkylammonium halide or aminopropyltrialkoxysilane is preferable. It is preferable that the addition ratio is 5% by weight or less of the total solid content of the hydrophilic layer.

Further, a hydrophilic light-to-heat conversion material may be added to the hydrophilic layer of the present invention in order to enhance heat sensitivity. A particularly preferred photothermal conversion material is a water-soluble infrared-absorbing dye, and is a cyanine dye having a sulfonic acid group or an alkali metal base of sulfonic acid or an amine base of the formula (I). The addition ratio of these dyes is 1 to the total amount of the hydrophilic layer.
% To 20% by weight, more preferably 5% to 15% by weight.
% By weight.

The coating thickness of the three-dimensionally crosslinked hydrophilic layer of the present invention is preferably 0.1 μm to 10 μm. More preferably, it is 0.5 μm to 5 μm. If it is too thin, the durability of the hydrophilic layer will be poor, and the printing durability during printing will be poor. On the other hand, if the thickness is too large, the resolution is reduced. Hereinafter, the intermediate layer made of an organic polymer will be described. Organic polymers that can be used for the intermediate layer include polyurethane resins, polyester resins, acrylic resins, cresol resins, resole resins,
Any commonly used organic polymer such as polyvinyl acetal resin and vinyl resin can be used without any problem. It is preferred that these are the coating weight of ^{0.1g / m 2 ~5.0g / m 2} . When it is 0.1 g / m ² or less, the heat insulating effect is small, and when it is more than 5.0 g / m ² , the printing durability of the non-image portion is deteriorated.

[Plate making and printing] The lithographic printing plate precursor of the present invention can form an image by high-power laser exposure, but a writer such as a thermal head may be used. In particular, in the present invention, it is preferable to use a laser that emits light in the infrared or near infrared region. In particular, a laser diode that emits light in the near infrared region is particularly preferable. Although recording by an ultraviolet lamp is also possible, in the present invention, it is preferable that the image is exposed by a solid-state laser or a semiconductor laser that emits infrared rays having a wavelength of 760 nm to 1200 nm. The output of the laser is preferably 100 mW or more, and it is preferable to use a multi-beam laser device in order to shorten the exposure time. Further, the exposure time per pixel is preferably within 20 μsec. The energy applied to the recording material is preferably from 10 to 300 mJ / cm ² .

The plate thus exposed is mounted without processing on a cylinder of a printing press.
The plate thus mounted can be printed in the following procedure. (1) A method in which dampening water is supplied to the printing plate and development is performed on the machine, and then ink is further supplied to start printing. (2) A dampening solution and ink are supplied to the printing plate and developed on the machine. And (3) supplying ink to the plate, supplying dampening water and simultaneously supplying paper to start printing, and the like. These plates are disclosed in Japanese Patent No. 2938398.
As described in the above, after mounting on the printing press cylinder, it is also possible to expose by a laser mounted on the printing press and then apply on-press development with dampening water and / or ink. Preferably, it can be developed with water or an aqueous solution, or can be directly attached to a printing machine for printing without development.

[0111]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should be understood that the scope of the present invention is not limited by these Examples.

<Synthesis Example of Fine Particle (1)> Ethyl acetate
Cresol novolak resin having a weight average molecular weight of 4000 (meta / para ratio of 60
/ 40) 4.0 g of polymethyl methacrylate having a weight-average molecular weight of 15,000, 2.0 g of a photothermal conversion agent (I-34 described in this specification), 1.5 g of anionic surfactant pionin A-
0.1 g of 41C (manufactured by Takemoto Oil & Fat Co., Ltd.) was dissolved to prepare an oil phase. An aqueous phase of 36.0 g of a 4% aqueous solution of polyvinyl alcohol and PVA205 (manufactured by Kuraray Co., Ltd.) was added thereto, and the mixture was emulsified with a homogenizer at 15000 rpm for 15 minutes. Water 2
After adding 4.0 g, the solution was heated at 40 ° C. for 3 hours while removing the organic solvent. The measured solid content was 13.0% by weight. The average particle size is 0.25
μm.

<Synthesis Example of Fine Particle (2)> Ethyl acetate
Cresol novolak resin having a weight average molecular weight of 4000 (meta / para ratio of 60 / g) was added to 0 g and 6.0 g of methyl ethyl ketone.
40) 4.0 g, 2.0 g of epoxy resin epicoat 1007 (manufactured by Yuka Shell Epoxy Co., Ltd.), 1.5 g of photothermal conversion agent (I-34 described in this specification), Pionin A-41C (Takemoto Yushi Co., Ltd.) ) Was dissolved to prepare an oil phase. Hereinafter, in the same manner as in the synthesis example of the fine particles (1), a solid content concentration of 1
A dispersion of fine particles (2) having a weight percentage of 4.0% and an average particle diameter of 0.30 μm was prepared.

<Synthesis Example of Fine Particle (3)> Ethyl acetate
Cresol novolak resin having a weight average molecular weight of 4000 (meta / para ratio of 60 / g) was added to 0 g and 6.0 g of methyl ethyl ketone.
40) 4.0 g, 2.0 g of a polyurethane resin having a weight average molecular weight of 8000 obtained by subjecting isophorone diisocyanate and butanediol to a polyaddition reaction, and 1.5 g of a photothermal conversion agent (I-34 described in the present specification); Pionein A-41C
0.1 g was dissolved to prepare an oil phase. Hereinafter, fine particles (1)
In the same manner as in Synthesis Example, a dispersion liquid of fine particles (3) having a solid content of 13.5% by weight and an average particle diameter of 0.25 μm was prepared.

<Synthesis Example of Fine Particles (4) (Comparative Example)> 12.0 g of ethyl acetate and 6.0 g of methyl ethyl ketone were mixed with 6.0 g of a cresol novolak resin having a weight-average molecular weight of 4000 and an m- / p-ratio of 6/4, Conversion agent (I-3 described herein)
4) 1.5 g and 0.1 g of Pionin A-41C were dissolved to prepare an oil phase. The same aqueous phase as in the synthesis example of the fine particles (1) was added thereto, and emulsification was carried out using a homogenizer in the same manner. Water 24.
After the addition of 0 g, the solution was heated at 40 ° C. for 3 hours while skipping ethyl acetate and methyl ethyl ketone. The measured solid content was 14.0% by weight. The average particle size was 0.20 μm.

<Synthesis Example of Fine Particle (5) (Comparative Example)> 12.0 g of ethyl acetate and 6.0 g of methyl ethyl ketone were added to
Polymethyl methacrylate 6.0 having a weight average molecular weight of 15,000
g, 1.5 g of a photothermal conversion agent (I-34 described herein),
0.1 g of Pionein A-41C was dissolved to prepare an oil phase.
Hereinafter, in the same manner as in the synthesis example of the fine particles (1), a solid content concentration of 1
A dispersion of fine particles (5) having a weight percentage of 4.5% and an average particle diameter of 0.24 μm was prepared.

<Synthesis Example of Fine Particle (6) (Comparative Example)> 12.0 g of ethyl acetate and 6.0 g of methyl ethyl ketone were added to an epoxy resin Epicoat 1007 (Yuika Shell Epoxy Co., Ltd.).
6.0 g) and 0.1 g of Pionin A-41C were dissolved to prepare an oil phase. Hereinafter, in the same manner as in the synthesis example of the fine particles (1), the solid content concentration is 15.0% by weight, and the average particle size is 0.50 μm.
A dispersion liquid of m fine particles (6) was prepared.

<Synthesis Example of Fine Particle (7) (Comparative Example)> 6.0 g of a polyurethane resin having a weight average molecular weight of 8000 synthesized from isophorone diisocyanate and butanediol in 12.0 g of ethyl acetate and 6.0 g of methyl ethyl ketone, and photothermal 1.5 g of the conversion agent (I-34 described in this specification) and 0.1 g of Pionin A-41C were dissolved to prepare an oil phase. Hereinafter, in the same manner as in the synthesis example of the fine particles (1), a solid content concentration of 1
A dispersion of fine particles (7) having 5.0% by weight and an average particle diameter of 0.45 μm was prepared.

<Synthesis Example of Fine Particle (8)> A fine particle (8) was prepared in the same manner as the fine particle (1) except that the photothermal conversion agent was omitted. The measured solid content was 14.0% by weight. The average particle size was 0.20 μm.

(Production Example 1 of Support) A JIS A1050 aluminum material containing 0.01% of copper, 0.03% of titanium, 0.3% of iron and 0.1% of silicon has a thickness of 0.1%. The surface of a 24 mm rolled plate is sand-grained using a 400-mesh 20% by weight aqueous suspension of pamistone (manufactured by Kyoritsu Ceramics) and a rotating nylon brush (6-10 nylon) having a brush diameter of 0.30 mm. After that, it was washed well with water.

The aluminum plate was immersed in a 15% by weight aqueous sodium hydroxide solution (containing 5% by weight of aluminum) and etched so that the amount of aluminum dissolved was 5 g / m ² , and then washed with running water. Further, the mixture was neutralized with 1% by weight of nitric acid, and then, in an aqueous solution of 0.7% by weight of nitric acid (containing 0.5% as aluminum ions), a cathode voltage of 9.3.
A voltage of 160 coulombs / dm ² using a rectangular wave alternating waveform voltage of 10.5 volts (current ratio r = 0.90, current waveform described in Examples of Japanese Patent Publication No. 58-5796). The electrolytic surface roughening treatment was performed using the quantity of electricity. After washing with water, it was immersed in a 10% by weight aqueous solution of sodium hydroxide at 40 ° C., etched so that the amount of aluminum dissolved was 1 g / m ² , and then washed with water. Next, it was immersed in a 30% aqueous sulfuric acid solution at 50 ° C., desmutted, and washed with water. Further, a porous anodic oxide film forming treatment was performed in a 20% by weight sulfuric acid aqueous solution (containing 0.8% as aluminum ions) at 35 ° C. using a direct current. That is, the current density is 13 A /
Electrolysis was performed at dm ² , and the electrolysis time was adjusted to an anodic oxide film weight of 4.0 g / m ² , followed by washing with water and drying.

The aluminum support (Support A) obtained as described above had a reflection density of 0.28 and a center line surface roughness (Ra) of 0.45 μm. The reflection density was measured with a Macbeth RD920 reflection densitometer, and the center line surface roughness was measured.
(Ra) is a SURFCOM stylus meter (probe 10μ)
R). The support A was immersed in a 0.5% by weight aqueous solution of polyvinylphosphonic acid at 60 ° C. for 10 seconds, washed with water and dried to obtain a support (1).

(Production Example 2 of Support) Support (2) was obtained by coating gum arabic at 10 mg / m ² on support (1).

[Examples 1 to 5 and Comparative Examples 1 to 3] The supports obtained in the above Production Examples and the image forming layer coating solutions (1) and (2) having the following compositions were combined with the combinations shown in Table 1. To prepare a heat-sensitive lithographic printing plate precursor. The application of the image forming layer is performed by bar application, and drying conditions are oven use, 90 ° C.
120 seconds, and the dry coating amount of the image forming layer is 0.8 g / m2.
^{Was 2} .

<Image Forming Layer Coating Solution (1)> Water 30 g Fine particles (in terms of solid content) 2.0 g Megafac F-171 0.1 g (Fluorine-based surfactant manufactured by Dainippon Ink and Chemicals, Inc.)

<Image Forming Layer Coating Solution (2)> Water 30 g Fine particles (in terms of solid content) 2.0 g Megafax F-171 0.1 g Light-to-heat converting agent (I-34) 0.20 g

[0127]

[Table 1]

The lithographic printing plate precursor thus obtained, which can be developed on a press, was subjected to output of 9 W, an external drum rotation speed of 210 rpm, and a plate surface by a Creo Trendsetter 3244VFS equipped with a water-cooled 40 W infrared semiconductor laser. After exposure under the conditions of energy of 100 mJ / cm ² and resolution of 2400 dpi, without processing, it was mounted on a cylinder of a printing machine SOR-M manufactured by Heidelberg, supplied with dampening water, supplied with ink, and further supplied with paper. Printing was performed.
All the original plates could be developed on-press without any problems and were printable. The number of prints (printing durability) obtained on each original plate and the level of stain resistance were evaluated. Table 1 shows the evaluation results.

As is clear from the results shown in Table 1, each of the lithographic printing plate precursors of Examples 1 to 5 of the present invention had excellent printing durability and good background smear, and satisfactory results were obtained. , Comparative Example 1
Each of the planographic printing plate precursors Nos. 1 to 4 was unsatisfactory in terms of printing durability.

[0130]

According to the lithographic printing plate precursor of the present invention, when heat is applied by scanning exposure based on a digital signal, a phenol resin, an acrylic resin, a urethane resin and an epoxy resin contained in the image forming layer are formed. The fine particles containing at least one selected from the group consisting of the groups react in the heat mode, thereby improving the film strength of the heated image area and the adhesion to the substrate while exhibiting good on-press developability. Thus, it became possible to obtain a lithographic printing plate having excellent printing durability.

Continued on the front page F term (reference) 2H025 AA04 AA12 AB03 AC08 AD01 BD21 BD43 BD53 CB14 CB22 CB28 CB30 FA14 2H096 AA06 BA06 EA04 EA23 GA60 2H114 AA04 AA24 BA01 BA10 DA03 DA04 DA07 DA11 DA15 DA34 DA55 DA55 DA55 DA53 DA53 DA55

Claims (2)

[Claims] 1. A phenolic resin on a hydrophilic support,
A lithographic printing plate precursor comprising an image forming layer containing fine particles containing at least one selected from the group consisting of an acrylic resin, a urethane resin and an epoxy resin. 2. The lithographic printing plate precursor according to claim 1, wherein the fine particles contain a photothermal conversion agent.