JP2009265472A - Planographic printing plate material and method for manufacturing planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planographic printing plate material suitable to exposure to an IR laser beam, having high sensitivity and excellent environmental aptitude. <P>SOLUTION: The planographic printing plate material has an image forming layer containing an alkali-soluble resin and organic particles chemically modified with an acid generating agent or organic particles chemically modified with photo-thermal conversion coloring matter, on a support body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate material, and more particularly to a lithographic printing plate material having a positive image forming layer used in a so-called computer-to-plate (hereinafter referred to as “CTP”) system.

  In recent years, with the digitization of plate making data, a so-called CTP system that modulates digital data directly into a laser signal and exposes a lithographic printing plate material has become widespread. In recent years, the development of lasers has been remarkable. Particularly, solid lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared can be easily obtained with high output and small size. These lasers are very useful as an exposure light source when directly making a plate from digital data such as a computer.

  As an infrared laser lithographic printing plate material, (A) an alkaline aqueous solution-soluble resin having a phenolic hydroxyl group such as a cresol novolac resin and (B) a positive lithographic printing plate material having a recording layer containing an infrared absorber has been proposed. (See Patent Document 1).

  Further, in the positive type lithographic printing plate material, higher sensitivity is required from the demand for improved workability, and a strong alkaline developer having a pH of 12 or more is required as a developer, and environmental suitability is not sufficient. There was a problem.

  In order to solve these problems, for example, a lithographic printing plate material having an image forming layer containing a compound capable of generating an acid and a compound decomposable by an acid and having improved sensitivity is known (patent) Reference 2).

  In these lithographic printing plate materials, further improvement in sensitivity is required, and a photosensitive lithographic printing plate compatible with an inexpensive and small-sized infrared laser is required, and a technology for meeting such market needs. It has been known. For example, a technique of using a polymer compound in which a specific acid group is crosslinked in an image forming layer (see Patent Document 3) or a technique of forming fine protrusions by adding a particulate material (see Patent Document 4) is disclosed. .

However, these lithographic printing plate materials are still not satisfactory in terms of high sensitivity.
International Publication No. 97/39894 Pamphlet JP-A-11-133610 Japanese Patent Laid-Open No. 11-277828 JP 2004-86138 A

  An object of the present invention is to provide a lithographic printing plate material that is suitable for exposure with an infrared laser, has high sensitivity, and is excellent in environmental suitability.

The above object of the present invention is achieved by the following configurations.
1. A lithographic printing plate material comprising an image-forming layer containing an alkali-soluble resin and organic particles chemically modified with an acid generator or organic particles chemically modified with a photothermal conversion dye on a support.
2. A method for preparing a lithographic printing plate, comprising subjecting the lithographic printing plate material according to 1 to image exposure and developing with a developer having a pH value of 2 to 10 at 25 ° C. after the image exposure.

  In the above configuration 1, from the viewpoint of sensitivity, an embodiment in which the image forming layer contains organic particles chemically modified with an acid generator and organic particles chemically modified with a photothermal conversion dye is a more preferable embodiment.

  According to the above configuration of the present invention, it is possible to provide a lithographic printing plate material which is suitable for exposure with an infrared laser, has high sensitivity and is excellent in environmental suitability.

  Hereinafter, the present invention will be described in more detail.

  The present invention is characterized in that an image-forming layer containing organic particles chemically modified with an alkali-soluble resin and an acid generator or organic particles chemically modified with a photothermal conversion dye is provided on a support.

  In the present invention, a lithographic printing plate material having high sensitivity and excellent environmental suitability can be obtained by incorporating an organic particle to which an acid generator or a photothermal conversion dye is bound in the image forming layer.

(Image forming layer)
(Alkali-soluble resin)
The alkali-soluble resin according to the present invention is a resin that dissolves in an aqueous potassium hydroxide solution having a pH of 13 at 25 g at 0.1 g / l or more.

  As the alkali-soluble resin, a novolak resin, an acrylic resin, or an acetal resin is preferably used from the viewpoint of ink inking property, alkali solubility, and the like.

  The alkali-soluble resin may have a single configuration, but may be a combination of two or more.

(Novolac resin)
The novolak resin is synthesized by condensing various phenols with aldehydes.

  Phenols include phenol, m-cresol, p-cresol, m- / p-mixed cresol, phenol and cresol (any of m-, p-, or m- / p-mixed), 2,3- Xylenol, 2,4-xylenol, 2,5-xylenol, 2.6-xylenol, 3.4-xylenol, 3,5-xylenol, pyrogallol, acrylamide having a phenol group, methacrylamide, acrylic ester, methacrylic ester Or hydroxystyrene. In addition, substituted phenols such as isopropylphenol, t-butylphenol, t-amylphenol, hexylphenol, cyclohexylphenol, 3-methyl-4-chloro-6-t-butylphenol, isopropylcresol, t-butylcresol, and t-amylresole. Is mentioned. Preferably, t-butylphenol and t-butylcresol can also be used. On the other hand, examples of aldehydes include aliphatic and aromatic aldehydes such as formaldehyde, acetaldehyde, acrolein, and crotonaldehyde. Preferred is formaldehyde or acetaldehyde, and most preferred is formaldehyde.

  Among the above combinations, preferably phenol-formaldehyde, m-cresol-formaldehyde, p-cresol-formaldehyde, m- / p-mixed cresol-formaldehyde, phenol / cresol (m-, p-, o-, m- / Any of p-mixing, m- / o-mixing and o- / p-mixing.) Mixing-formaldehyde, cresol / xylenol / formaldehyde. Particularly preferred are cresol (m-, p-mixed) · formaldehyde and cresol · xylenol · formaldehyde.

  These novolak resins preferably have a weight average molecular weight of 1,000 or more and a number average molecular weight of 200 or more. More preferably, the weight average molecular weight is 1,500 to 300,000, the number average molecular weight is 300 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 20. . Particularly preferably, the weight average molecular weight is 2,000 to 50,000, the number average molecular weight is 500 to 35,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. . By setting it as the above range, the film strength, alkali solubility, chemical solubility, interaction property with the photothermal conversion substance, etc. of the novolak resin can be appropriately adjusted, and the effects of the present invention can be easily obtained.

  As the weight average molecular weight, a value in terms of polystyrene determined by a gel permeation chromatography (GPC) method using monodisperse polystyrene of novolak resin as a standard is adopted.

  As a method for producing a novolak resin, for example, as described in “New Experimental Chemistry Course [19] Polymer Chemistry [I]” (1993, Maruzen Publishing), Item 300, phenol and substituted phenols (for example, xylenol) , Cresols, etc.) in a solvent using acid as a catalyst together with an aqueous formaldehyde solution to dehydrate and condense phenol, the o-position or p-position of the substituted phenol component, and formaldehyde. After dissolving the novolak resin thus obtained in an organic polar solvent, an appropriate amount of a nonpolar solvent is added and left for several hours, whereby the novolak resin solution is separated into two layers. By concentrating only the lower layer of the separated solution, a novolak resin with a concentrated molecular weight can be produced.

  Examples of the organic polar solvent used include acetone, methyl alcohol, and ethyl alcohol. Examples of the nonpolar solvent include hexane and petroleum ether. In addition to the production method described above, for example, as described in JP-T-2001-506294, a novolak resin is dissolved in a water-soluble organic polar solvent, and then water is added to form a precipitate. A novolak resin fraction can also be obtained. Furthermore, in order to obtain a novolak resin having a low degree of dispersion, it is possible to use a method in which a novolak resin obtained by dehydration condensation of phenol derivatives is dissolved in an organic polar solvent and then applied to silica gel for molecular weight fractionation.

  The dehydration condensation of the o-position or the p-position of the phenol and the substituted phenol component with formaldehyde gives a concentration of 60 to 90% by mass, preferably 70 to 80% by mass as the total mass of the phenol and the substituted phenol component. In the solvent solution, the molar ratio of formaldehyde to the total number of moles of phenol and substituted phenol components is 0.2 to 2.0, preferably 0.4 to 1.4, particularly preferably 0.6 to 1.2. In addition, the acid catalyst has a molar ratio with respect to the total number of moles of phenol and substituted phenol components of 0.01 to 0.1, preferably 0.02 to 0.05. It can be performed by adding under temperature conditions and stirring for several hours while maintaining the temperature range. In addition, it is preferable that reaction temperature is the range of 70 to 150 degreeC, and it is more preferable that it is the range of 90 to 140 degreeC.

  A novolac resin may be used independently and may use 2 or more types together. By combining two or more kinds, it is possible to effectively use different characteristics such as film strength, alkali solubility, solubility in chemicals, and interaction with a photothermal conversion substance, which is preferable. When two or more kinds of novolak resins are used in combination in the image recording layer, it is preferable to combine those having as much difference as possible, such as weight average molecular weight and m / p ratio. For example, the weight average molecular weight preferably has a difference of 1000 or more, more preferably 2000 or more. The m / p ratio preferably has a difference of 0.2 or more, more preferably 0.3 or more.

  The addition amount of the resin having a phenolic hydroxyl group is preferably 30 to 99% by mass and more preferably 45 to 95% by mass with respect to the solid content of the upper layer from the viewpoint of chemical resistance and printing durability. Preferably, it is the range of 60-90 mass%.

(acrylic resin)
The acrylic resin is preferably a copolymer containing the following structural units. Other structural units that can be suitably used include, for example, acrylic esters, methacrylic esters, acrylamides, methacrylamides, vinyl esters, styrenes, acrylic acid, methacrylic acid, acrylonitrile, maleic anhydride, maleic Examples thereof include structural units introduced from known monomers such as acid imides and lactones.

  Specific examples of acrylates that can be used include methyl acrylate, ethyl acrylate, (n- or i-) propyl acrylate, (n-, i-, sec- or t-) butyl acrylate, amyl acrylate, 2 -Ethylhexyl acrylate, dodecyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 5-hydroxypentyl acrylate, cyclohexyl acrylate, allyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl Acrylate, methoxybenzyl acrylate, chlorobenzyl acrylate, 2- (p-hydroxyphenyl) ethyl acetate Rate, furfuryl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, chlorophenyl acrylate, sulfamoyl phenyl acrylate, and the like.

  Specific examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, (n- or i-) propyl methacrylate, (n-, i-, sec- or t-) butyl methacrylate, amyl methacrylate, 2-ethylhexyl methacrylate, Dodecyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 5-hydroxypentyl methacrylate, cyclohexyl methacrylate, allyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, methoxybenzyl methacrylate, chloro Benzyl methacrylate, 2- (p-hydroxyphenyl) ethyl methacrylate Rate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, chlorophenyl methacrylate, sulfamoylphenyl methacrylate and the like.

  Specific examples of acrylamides include acrylamide, N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, N-benzylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, and N-tolylacrylamide. N- (p-hydroxyphenyl) acrylamide, N- (sulfamoylphenyl) acrylamide, N- (phenylsulfonyl) acrylamide, N- (tolylsulfonyl) acrylamide, N, N-dimethylacrylamide, N-methyl-N- Examples include phenylacrylamide, N-hydroxyethyl-N-methylacrylamide, N- (p-toluenesulfonyl) acrylamide and the like.

  Specific examples of methacrylamides include methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-butylmethacrylamide, N-benzylmethacrylamide, N-hydroxyethylmethacrylamide, N -Phenylmethacrylamide, N-tolylmethacrylamide, N- (p-hydroxyphenyl) methacrylamide, N- (sulfamoylphenyl) methacrylamide, N- (phenylsulfonyl) methacrylamide, N- (tolylsulfonyl) methacrylamide N, N-dimethylmethacrylamide, N-methyl-N-phenylmethacrylamide, N- (p-toluenesulfonyl) methacrylamide, N-hydroxyethyl-N-methylmethacrylamide and the like.

  Specific examples of lactones include pantoyl lactone (meth) acrylate, α- (meth) acryloyl-γ-butyrolactone, and β- (meth) acryloyl-γ-butyrolactone.

  Specific examples of maleic imides include maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide and the like.

  Specific examples of vinyl esters include vinyl acetate, vinyl butyrate, vinyl benzoate and the like.

  Specific examples of styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, propyl styrene, cyclohexyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, methoxy styrene, dimethoxy styrene. Chlorostyrene, dichlorostyrene, bromostyrene, iodostyrene, fluorostyrene, carboxystyrene and the like.

  Specific examples of acrylonitriles include acrylonitrile and methacrylonitrile.

  Among these monomers, acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, acrylic acid, methacrylic acid, acrylonitriles, maleic imides having 20 or less carbon atoms are particularly preferably used. is there.

  The molecular weight of the copolymer using these is preferably 2000 or more in terms of weight average molecular weight (Mw), more preferably in the range of 50,000 to 100,000, and particularly preferably in the range of 10,000 to 50,000.

  The polymerization form of the acrylic resin may be any of random polymer, block polymer, graft polymer, etc., but is a block polymer capable of phase separation of hydrophilic group and hydrophobic group in that the solubility of developer can be controlled. Is preferred.

  An acrylic resin may be used independently or may be used in mixture of 2 or more types.

(Acetal resin)
The polyvinyl acetal resin can be synthesized by a method in which polyvinyl alcohol is acetalized with an aldehyde and the remaining hydroxy group is reacted with an acid anhydride.

  Examples of the aldehyde used herein include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, pentylaldehyde, hexylaldehyde, glyoxylic acid, N, N-dimethylformamide di-n-butyl acetal, bromoacetaldehyde, chloroacetaldehyde, 3-hydroxy- Examples include, but are not limited to, n-butyraldehyde, 3-methoxy-n-butyraldehyde, 3- (dimethylamino) -2,2-dimethylpropionaldehyde, cyanoacetaldehyde, and the like.

  As the acetal resin, a polyvinyl acetal resin represented by the following general formula (PVAC) is preferably used.

  In general formula (PVAC), n1 represents 5-85 mol%, n2 represents 0-60 mol%, and n1 represents 0-60 mol%.

  The structural unit (i) is a group derived from polyvinyl acetal, the structural unit (ii) is a group derived from polyvinyl alcohol, and the structural unit (iii) is a group derived from a vinyl ester.

In the structural unit (i), R ¹ represents an alkyl group which may have a substituent, a hydrogen atom, a carboxyl group, or a dimethylamino group.

Examples of the substituent include a carboxyl group, a hydroxyl group, a chloro group, a bromo group, a urethane group, a ureido group, a tertiary amino group, an alkoxy group, a cyano group, a nitro group, an amide group, and an ester group. Specific examples of R ¹ include a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a carboxy group, a halogen atom (—Br, —Cl, etc.) or a methyl group substituted with a cyano group, 3 -Hydroxybutyl group, 3-methoxybutyl group, phenyl group and the like can be mentioned, among which hydrogen atom, propyl group and phenyl group are particularly preferable.

  Moreover, n1 is the range of 5-85 mol% from the surface of printing durability and applicability | paintability, and it is more preferable that it is the range of 25-70 mol%.

  In the structural unit (ii), n2 is in the range of 0 to 60 mol%, and more preferably in the range of 10 to 45 mol%, from the viewpoint of printing durability.

In the structural unit (iii), R ² represents an alkyl group having no substituent, an aliphatic hydrocarbon group having a carboxyl group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group. The hydrogen group represents 1 to 20 carbon atoms. Among these, an alkyl group having 1 to 10 carbon atoms is preferable, and a methyl group and an ethyl group are particularly preferable from the viewpoint of developability. n3 is in the range of 0 to 20 mol% from the standpoint of printing durability, and more preferably in the range of 1 to 10 mol%.

  The acid content of the polyvinyl acetal resin is preferably in the range of 0.5 to 5.0 meq / g (that is, 84 to 280 in terms of mg of KOH) in terms of sensitivity and development latitude, and is preferably 1.0 to 3 More preferably, it is 0.0 meq / g.

  The molecular weight of the polyvinyl acetal resin is preferably about 5,000 to 400,000, more preferably about 20,000 to 300,000, as a weight average molecular weight measured by gel permeation chromatography. By making it into the above range, the film strength, alkali solubility, solubility in chemicals, etc. can be adjusted, and the effects of the present invention can be easily obtained.

  In addition, these polyvinyl acetal resins may be used independently or may be used in mixture of 2 or more types.

  Acetalization of polyvinyl alcohol can be carried out according to known methods, for example, US Pat. No. 4,665,124; US Pat. No. 4,940,646; US Pat. No. 5,169,898; US Pat. No. 5,700,809; US Pat. No. 5,792,823; No. 09328519 and the like.

  The planographic printing plate material according to the present invention may have a plurality of image forming layers. In this case, for example, in the case of having two layers of the lower layer and the upper layer of the image forming layer, the alkali-soluble resin used for the lower layer is preferably mainly an acrylic resin or an acetal resin in terms of alkali solubility, etc. As the alkali-soluble resin used in the ink, a novolak resin is preferable from the viewpoint of ink inking property.

(Organic particles chemically modified with acid generator, organic particles chemically modified with photothermal conversion dye)
The organic particles chemically modified with the acid generator according to the present invention are those in which an acid generator residue is covalently bonded to the organic particles, or organic particles and organic particles are ionically bonded.

  The organic particles chemically modified with the photothermal conversion dye according to the present invention are those in which the photothermal conversion dye residue is covalently bonded to the organic particles, or the organic particles and the photothermal conversion dye are ionically bonded.

  As the organic particles according to the present invention, a polymer having a cationic group is preferably used. In this case, the acid generator or the photothermal conversion dye is anionized and bonded to the organic particles.

  As the polymer having a cationic group, a latex polymer having 4 sphere nitrogen atoms is preferably used.

  Examples of the monomer unit forming the latex polymer include those represented by the following general formula [1] to general formula [5].

In the general formulas [1] to [5], X ⁻ represents an anion. That is, halogen ions, sulfate ions, phosphate ions, sulfonate ions, acetate ions, and the like. The R bonded to N ⁺ may be the same or different, and each R is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (for example, methyl, ethyl, propyl, isobutyl, pentyl, hexyl, heptyl) , Decyl groups), alkenyl groups (eg propenyl, butynyl groups), or aryl groups having 6 to 20 carbon atoms (eg phenyl, naphthyl groups), aralkyl groups (eg benzyl, phenethyl, Each group of naphthylmethyl) or an alkaryl group (for example, each group of tolyl and xylyl). Z represents a group of non-metallic atoms necessary for forming an unsaturated heterocyclic ring, and is preferably an imidazole, pyridine, piperidine, pyrrole or morpholine ring. n represents an integer.

  The cationic monomer that forms the cationic latex polymer preferably forms a copolymer with a non-cationic monomer in order to adjust water solubility. Examples of such non-cationic monomers include acrylic acid, methacrylic acid ester, styrene, alkylene, ether, vinyl acetate, acrylonitrile and the like. Further, the cationic latex polymer is preferably cross-linked with a monomer having two or more functional groups such as divinylbenzene and dimethacrylate and manufactured by emulsion polymerization.

  In the case of forming a copolymer, the cationic monomer is preferably contained in the cationic latex polymer in an amount of 5 to 95% by polymerization, and more preferably in the range of 25 to 65% by mass. Moreover, it is preferable that a non-cationic monomer contains 5-95 mass% in a cationic latex polymer, and it is preferable that a crosslinkable monomer is contained 0.1-8 mass% among them.

  As an example of the synthesis of a cationic latex polymer, as described in the examples of JP-A-51-73440, vinylbenzyl chloride is emulsion-polymerized with other monomers and then quaternized with a tertiary amine. The technology to do is known.

  A particularly preferred cationic latex polymer is a latex polymer produced by quaternizing a latex polymer having a tertiary amine obtained by emulsion polymerization with a quaternizing agent. As an example of this synthesis, there is a technique described in JP-A-55-22766.

  Another particularly preferred cationic latex polymer having a quaternary nitrogen atom is a latex polymer produced by emulsion polymerization of a quaternary nitrogen-containing monomer with a lipophilic monomer. The synthesis method is selected from various known methods. One example is described in Japanese Patent Application Laid-Open No. 56-17352.

  It is particularly desirable that the cationic latex polymer is produced by a synthesis method that orients more cations on the latex particle surface. As a production method, a method in which a latex polymer having a tertiary amine is first synthesized by emulsion polymerization and then quaternized with a quaternizing agent is most suitable.

  Another useful method for synthesizing a cationic latex polymer is a method for producing a quaternary nitrogen atom-containing monomer by emulsion polymerization with a suitable lipophilic monomer. This synthesis method is suitable when the cationic latex polymer contains a small proportion (preferably 5 to 30% by mass) of cationic monomer units.

  The chemically modified organic particles are mixed with a dispersion containing the cationic latex polymer and an aqueous solution containing an acid generator or a photothermal conversion dye having an anionic group, and the resulting precipitate is filtered. It can be recovered and washed with water.

  Particles chemically modified with covalent bonds can be obtained by reacting polymer particles having reactive groups such as hydroxyl groups and amino groups with dyes or acid generators having reactive groups that react with hydroxyl groups and amino groups. Can do.

  For example, polymer particles having an amino group are usually produced by emulsion polymerization using a monomer having an amino group. Generally, organic particles are formed from 99 to 99.5% by mass of a polymer component and 10 to 0.5% by mass of a crosslinking agent. The polymer component can be varied during the polymerization process to produce core and shell organic particles having different compositions on the inside and outside. When a polymer binder is used, the mass ratio of organic particles to binder can be widely varied in the range of 1:20 to 1: 1.

  Examples of the monomer having a hydroxyl group used for the synthesis of polymer particles having a hydroxyl group include vinyl alcohol, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, N- (4-hydroxyethylphenyl) methacrylamide, Hydroxy-methyldiacetone (meth) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, om- or p-hydroxystyrene, o-, m- or p-hydroxy Examples include phenyl acrylate or methacrylate.

  Examples of the monomer having an amino group include acrylamide, methacrylamide, 2-aminoethyl vinyl ether, and p-aminostyrene.

  For covalent bonding, an acid having a reactive group that reacts with a hydroxyl group or an amino group under acidic conditions, such as a hydroxyl group and / or an amino group of an organic particle having a reactive group on the particle surface. What is necessary is just to make it react with a generator or a photothermal conversion pigment | dye.

  The average particle size of the organic particles according to the present invention is preferably 0.005 to 1.0 μm, particularly preferably 0.01 to 0.8 μm from the viewpoint of sensitivity.

  The average particle diameter is an average value of diameters when the volume is converted into a sphere, and is a value measured by a general particle size distribution measuring apparatus (for example, CAPA manufactured by Horiba, Ltd.).

  The content of the organic particles with respect to the image forming layer is preferably 2.5% by mass to 50% by mass, and particularly preferably 5% by mass to 25% by mass.

  Below, the photothermal conversion pigment | dye and acid generator which are couple | bonded with an organic particle are demonstrated.

<Photothermal conversion dye>
The photothermal conversion pigment has a light absorption region in the infrared region of 700 nm or more, preferably 750 to 1200 nm, and refers to a pigment (dye) that expresses light / heat conversion ability in the light of this wavelength range. Various pigments (dyes) that absorb light and generate heat can be used.

  As the photothermal conversion pigment, commercially available pigments and known pigments described in literature (for example, “Dye Handbook” edited by the Society of Synthetic Organic Chemistry, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes.

  Examples of dyes that absorb such infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-78787. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, Naphthoquinone dyes described in JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. Examples thereof include squarylium dyes described in 58-112792 and cyanine dyes described in British Patent 434,875. Further, near-infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzo (thio) pyrylium described in US Pat. No. 3,881,924. Salts, trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59 -84248, 59-84249, 59-146063, 59-146061, pyrylium compounds described in JP-A-59-216146, cyanine dyes described in U.S. Pat. No. 4,283,475 Pentamethine thiopyrylium salt described in No. 5 and pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702, E olight III-178, Epolight III-130, Epolight III-125 and the like are particularly preferably used.

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Furthermore, a cyanine dye represented by the following general formula (a) can be preferably used.

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , —X ² -L ¹ or a group represented by the following formula 1.

In the above formula, Xa ^- has 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.

Here, X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a carbon atom having 1 to 12 carbon atoms including a hetero atom. Indicates a hydrogen group. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. R ¹ and R ² may be bonded to each other to form a 5-membered ring or a 6-membered ring.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent.

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

  Specific examples of the cyanine dye represented by the general formula (a) are given below.

  Specific examples of the cyanine dye include those exemplified above, paragraph numbers [0017] to [0019] of JP-A No. 2001-133969, and paragraph numbers [0012] to [0038] of JP-A No. 2002-40638. And those described in paragraphs [0012] to [0023] of JP-A-2002-23360.

<Acid generator>
The acid generator is a compound capable of generating an acid upon image exposure, and includes various known compounds and mixtures.

For example, diazonium, phosphonium, sulfonium and iodonium salts such as BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , organohalogen compounds, orthoquinone-diazidosulfonyl chloride, and organometallic / organic Halogen compounds can also be used as the acid generator in the present invention. In addition, compounds that generate photosulfonic acid by photolysis, such as iminosulfonates described in JP-A-4-365048, etc., disulfone compounds described in JP-A-61-166544, JP-A-50- O-naphthoquinonediazide-4-sulfonic acid halide described in US Pat. No. 36209 (US Pat. No. 3,969,118), o-naphthoquinonediazide described in JP-A-55-62444 (UK Patent No. 2038801) or JP-B-1-11935 A compound can be mentioned. Examples of other acid generators include sulfonic acid alkyl esters such as cyclohexyl citrate, p-acetaminobenzene sulfonic acid cyclohexyl ester, p-bromobenzene sulfonic acid cyclohexyl ester, and alkyl sulfonic acid esters.

  Examples of the above-mentioned compounds forming hydrohalic acid include U.S. Pat. Nos. 3,515,552, 3,536,489 and 3,779,778, and West German Patent Publication No. 2, Examples thereof include those described in US Pat. No. 243,621, and compounds capable of generating an acid by photolysis described in, for example, West German Patent Publication No. 2,610,842 can also be used. Further, o-naphthoquinonediazide-4-sulfonic acid halogenide described in JP-A-50-36209 can be used.

  As the organic halogen compound, triazines having a halogen-substituted alkyl group and oxadiazoles having a halogen-substituted alkyl group are preferable, and s-triazines having a halogen-substituted alkyl group are particularly preferable. Specific examples of oxadiazoles having a halogen-substituted alkyl group include JP 54-74728, JP 55-24113, JP 55-77742, JP 60-3626, and JP And 2-halomethyl-1,3,4-oxadiazole compounds described in JP-A-60-138539.

  Of the compounds that decompose by light and generate an acid, those that are particularly effective are exemplified below.

  An oxazole derivative represented by the following general formula (PAG1) substituted with a trihalomethyl group or an S-triazine derivative represented by the general formula (PAG2).

In the formula, R ²¹ represents a substituted or unsubstituted aryl group or alkenyl group, R ²² represents a substituted or unsubstituted aryl group, alkenyl group, alkyl group, or —C (Y ¹ ) ₃ . Y ₃ represents a chlorine atom or a bromine atom. Specific examples include the following compounds, but are not limited thereto.

  An iodonium salt represented by the following general formula (PAG3), a sulfonium salt represented by the general formula (PAG4), or a diazonium salt.

Here, Ar ¹¹ and Ar ¹² each independently represents a substituted or unsubstituted aryl group. Preferred substituents include alkyl groups, haloalkyl groups, cycloalkyl groups, aryl groups, alkoxy groups, nitro groups, carboxyl groups, alkoxycarbonyl groups, hydroxy groups, mercapto groups, and halogen atoms.

Ar ²³ , Ar ²⁴ and Ar ²⁵ each independently represent a substituted or unsubstituted alkyl group or aryl group. Preferred are an aryl group having 6 to 14 carbon atoms, an alkyl group having 1 to 8 carbon atoms and substituted derivatives thereof. Preferred substituents are an aryl group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group, and a halogen atom. They are a C1-C8 alkoxy group, a carboxyl group, and an alkoxycarbonyl group.

Zb ⁻ represents a counter anion, for example, a BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ or the like. Fluoroalkanesulfonic acid anion, pentafluorobenzenesulfonic acid anion, naphthalene-1-sulfonic acid anion, bonded polynuclear aromatic sulfonic acid anion such as anthraquinonesulfonic acid anion, sulfonic acid group-containing dyes, and the like can be mentioned. Is not to be done.

  Specific examples include the following compounds, but are not limited thereto.

  The above-mentioned onium salts represented by the general formulas (PAG3) and (PAG4) are publicly known. W. Knapczzyk et al. Am. Chem. Soc. 91, 145 (1969), A.A. L. Maycok et al. Org. Chem. , 35, 2532, (1970), B.I. Goethas et al., Bull. Soc. Chem. Belg. 73, 546 (1964), H .; M.M. Leicester, J .; Ame. Chem. Soc. 51, 3587 (1929); V. Crivello et al. Polym. Chem. Ed. 18, 2677 (1980), U.S. Pat. Nos. 2,807,648 and 4,247,473, and JP-A-53-101331.

  A disulfone derivative represented by the following general formula (PAG5) or an iminosulfonate derivative represented by the general formula (PAG6).

In the formula, Ar ¹³ and Ar ¹⁴ each independently represent a substituted or unsubstituted aryl group. R ²⁶ represents a substituted or unsubstituted alkyl group or aryl group. A represents a substituted or unsubstituted alkylene group, alkenylene group, or arylene group.

  Specific examples include the following compounds, but are not limited thereto.

  In the present invention, the following acid generators can also be used. For example, a polymerization initiator described in JP-A-2005-70211, a compound capable of generating radicals described in JP-A-2002-537419, JP-A-2001-175006, JP-A-2002-278057, JP-A-2003-2003 In addition to the polymerization initiator described in JP-A-5363, an onium salt described in JP-A-2003-76010 having two or more cation moieties in one molecule, N- Nitrosamine compounds, compounds that generate radicals by the heat of JP-A-2001-343742, compounds that generate acid or radicals by the heat of JP-A-2002-6482, borate compounds of JP-A-2002-116539, JP-A-2002 -148790, a compound that generates an acid or a radical by heat, Light or thermal polymerization initiator having a polymerizable unsaturated group disclosed in JP-A-2002-207293, an onium salt having a divalent or higher anion as a counter ion in JP-A-2002-268217, and JP-A-2002-328465 Compounds such as a specific structure sulfonyl sulfone compound and a compound that generates radicals by heat described in JP-A No. 2002-341519 can be used as necessary.

  Among these, the compound represented by the following general formula (2) is preferable. This compound has particularly good safelight properties and is particularly preferable.

Formula (2) R ³¹ —C (X) ₂ — (C═O) —R ³²
In the formula, R ³¹ represents a hydrogen atom, bromine atom, chlorine atom, alkyl group, aryl group, acyl group, alkylsulfonyl group, arylsulfonyl group, iminosulfonyl group or cyano group. R ³² represents a hydrogen atom or a monovalent organic substituent. R ³¹ and R ³² may combine to form a ring. X represents a bromine atom or a chlorine atom.

Among the compounds represented by the general formula (2), those in which R ³¹ is a hydrogen atom, a bromine atom or a chlorine atom are preferably used from the viewpoint of sensitivity. The monovalent organic substituent represented by R ³² is not particularly limited as long as the compound of the general formula (2) generates a radical by light, but —R ³² is —O—R ³³ or —NR. ³⁴ -R ³³ (R ³³ represents a hydrogen atom or a monovalent organic substituent, and R ³⁴ represents a hydrogen atom or an alkyl group) is preferably used. Also in this case, in particular, those in which R ³¹ is a hydrogen atom, a bromine atom or a chlorine atom are preferably used from the viewpoint of sensitivity.

  Further, among these compounds, compounds having at least one acetyl group selected from a tribromoacetyl group, a dibromoacetyl group, a trichloroacetyl group and a dichloroacetyl group in the molecule are preferable. Further, from the viewpoint of synthesis, at least one selected from a tribromoacetoxy group, a dibromoacetoxy group, a trichloroacetoxy group and a dichloroacetoxy group, which is obtained by reacting a monovalent or polyvalent alcohol with the corresponding acid chloride. Tribromoacetylamide group, dibromoacetylamide group, trichloroacetylamide group, and dichloroacetyl obtained by reaction of a compound having an acetoxy group or a monovalent or polyvalent primary amine with the corresponding acid chloride. A compound having at least one acetylamide group selected from amide groups is particularly preferred. Further, compounds having a plurality of these acetyl groups, acetoxy groups, and acetamide groups are also preferably used. These compounds can be easily synthesized under the conditions of ordinary esterification or amidation reaction.

  A typical method for synthesizing the compound represented by the general formula (2) is to use an acid chloride such as tribromoacetic acid chloride, dibromoacetic acid chloride, trichloroacetic acid chloride, dichloroacetic acid chloride corresponding to each structure, alcohol, phenol In this reaction, a derivative such as an amine is esterified or amidated.

  Alcohols, phenols, and amines used in the above reaction are arbitrary, for example, monovalent alcohols such as ethanol, 2-butanol, 1-adamantanol, diethylene glycol, trimethylolpropane, dipentaerythritol, etc. Polyhydric alcohols Phenols such as phenol, pyrogallol, naphthol, monovalent amines such as morpholine, aniline, 1-aminodecane, polyvalent amines such as 1,2-dimethylpropylenediamine, 1,12-dodecanediamine, etc. Can be mentioned.

  Preferred specific examples of the compound represented by the general formula (2) include BR1 to BR69 and CL1 to CL50 described in paragraph numbers 0038 to 0053 of JP-A-2005-70211.

  The image forming layer according to the present invention preferably contains an acid-decomposable compound, and may further contain a visible image agent, a development accelerator, a development inhibitor, a sensitivity improver, a surfactant and the like.

(Acid-decomposable compound)
An acid-decomposable compound is a compound that can be decomposed by an acid generated by image exposure.

  Specific examples of the acid-decomposable compound include JP-A-48-89003, JP-A-512072014, JP-A-53-133429, JP-A-51-212995, JP-A-55-126236, and JP-A-56-17345. Compounds having a C—O—C bond described in the document, compounds having a Si—O—C bond described in the specifications of JP-A-60-37549 and JP-A-60-121446, Other acid-decomposable compounds described in the specifications of Kokai 60-3625 and 60-10247 are mentioned.

  Furthermore, compounds having a Si—N bond described in the specification of JP-A-62-222246, carbonate esters described in the specification of JP-A-62-251743, and JP-A-62-2 The ortho carbonate ester described in the specification of No. 209451, the ortho titanate ester described in the specification of JP-A No. 62-280842, and the specification of JP-A No. 62-280842 are described. Orthosilicate esters, acetals and ketals described in the specification of JP-A No. 2000-221676, compounds having a C—S bond described in the specification of JP-A No. 62-244038, The phenolphthalein, cresolphthalein and phenolsulfophthalein described in Kaikai 2005-91802 are protected with heat or acid-decomposable groups. Such compounds.

  Among these, the effect of the present invention is particularly great when a compound having at least one acetal or ketal group is used.

In _{particular, - (CH 2 CH 2 O} ) n- group (n is an integer of 2-5) compounds having preferably used. Further, among these compounds, compounds having an ethyleneoxy group chain number n of 3 or 4 are preferred. The - and dimethoxycyclohexane, benzaldehyde and substituted derivatives thereof Specific examples of the compound having a _(CH 2 CH 2 O) _n- group, diethylene glycol, triethylene glycol, produce condensation of any of tetraethylene glycol and pentaethylene glycol Things.

  Preferred examples of the acid-decomposable compound include compounds represented by the following general formula (ADC-1).

(In the formula, R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ may be bonded to each other with a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group to form a ring)
More preferred is a compound of the following general formula (ADC-2).

(Wherein R ₁₅ , R ₁₆ and R ₁₇ may be bonded to each other by a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group to form a ring. R ₁₇ is an alkylene group or a cycloalkylene group. An arylene group, and n and m are integers of 1 or more.)
The content of the acid-decomposable compound is preferably 5 to 70% by mass, particularly preferably 10 to 50% by mass, based on the total solid content of the composition forming the image forming layer. An acid-decomposable compound may be used alone or in combination of two or more.

  The acid-decomposable compound may be used alone or in combination of two or more.

  The preferable specific example of an acid-decomposable compound is shown below.

  The weight average molecular weight Mw measured by polystyrene conversion of gel permeation chromatography (GPC) of the acid-decomposable compound is preferably 500 to 30000, more preferably 1000 to 10000.

(Visible paint)
The image forming layer may contain a colorant as a visible paint. Examples of the colorant include oil-soluble dyes and basic dyes including salt-forming organic dyes.

  In particular, those which change color tone upon reaction with free radicals or acids can be preferably used. “Color tone changes” includes both a change from colorless to colored color tone and a change from colored to colorless or different colored tone. Preferred dyes are those that change color tone by forming a salt with an acid.

  For example, Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.), Oil Blue # 603 (Orient Chemical Industry Co., Ltd.), Patent Pure Blue (Sumitomo Sangoku Chemical Co., Ltd.), Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Violet, Methyl Triphenylmethane series represented by green, erythrosin B, pacific fuchsin, malachite green, oil red, m-cresol purple, rhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, cyano-p-diethylaminophenylacetanilide, etc. , Diphenylmethane-based, oxazine-based, xanthene-based, iminonaphthoquinone-based, azomethine-based or anthraquinone-based dyes that change from colored to colorless or different colored tones And the like as.

  On the other hand, examples of the color changing agent that changes from colorless to colored include leuco dyes and, for example, triphenylamine, diphenylamine, o-chloroaniline, 1,2,3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p'-bis. -Dimethylaminodiphenylamine, 1,2-dianilinoethylene, p, p ', p "-tris-dimethylaminotriphenylmethane, p, p'-bis-dimethylaminodiphenylmethylimine, p, p', p"- Primary or secondary typified by triamino-o-methyltriphenylmethane, p, p'-bis-dimethylaminodiphenyl-4-anilinononaphthylmethane, p, p ', p "-triaminotriphenylmethane These compounds can be used alone or in combination of two or more. To be used. In addition, particularly preferred dyes are Victoria Pure Blue BOH, an Oil Blue # 603.

  As the upper colorant, it is preferable to use a dye having an absorption maximum wavelength of less than 800 nm, particularly less than 600 nm. When the acid generator is used for the lower layer according to the above aspect, the upper colorant is preferable because transmission of light having a wavelength of visible light is suppressed and safelight properties are improved. An acid generator that can be used in the lower layer is also preferable because it can be used and printed even if the safelight property is not good.

  These dyes can be added to the printing plate material in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the upper layer or the lower layer.

(Development accelerator)
The image forming layer may contain a compound having a low molecular weight acidic group as a development accelerator for the purpose of improving the solubility as required.

  Examples of the acidic group include acidic groups having a pKa value of 7 to 11, such as a thiol group, a phenolic hydroxyl group, a sulfonamide group, and an active methylene group. The addition amount is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the lower layer.

(Development inhibitor)
The image forming layer may contain various dissolution inhibitors for the purpose of adjusting solubility. As the dissolution inhibitor, a disulfone compound or a sulfone compound as disclosed in JP-A-11-119418 is preferably used. As a specific example, 4,4′-bishydroxyphenylsulfone is preferably used. The addition amount is preferably 0.05 to 20% by mass, more preferably 0.5 to 10% by mass with respect to each layer.

  In addition, a development inhibitor can be contained for the purpose of enhancing dissolution inhibiting ability. The development inhibitor according to the present invention forms an interaction with the alkali-soluble resin, substantially lowers the solubility of the alkali-soluble resin in a developing solution in an unexposed area, and There is no particular limitation as long as the interaction is weakened and can be soluble in the developer, but quaternary ammonium salts, polyethylene glycol compounds and the like are particularly preferably used.

  Although it does not specifically limit as a quaternary ammonium salt, A tetraalkyl ammonium salt, a trialkyl aryl ammonium salt, a dialkyl diaryl ammonium salt, an alkyl triaryl ammonium salt, a tetraaryl ammonium salt, a cyclic ammonium salt, and a bicyclic ammonium salt are mentioned. .

  The addition amount of the quaternary ammonium salt is preferably 0.1 to 50% by mass and more preferably 1 to 30% by mass with respect to the total solid content of the upper layer from the viewpoint of the effect of suppressing development and film forming properties. preferable.

(Sensitivity improver)
The image forming layer may contain cyclic acid anhydrides, phenols, and organic acids for the purpose of improving sensitivity.

  Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride described in US Pat. No. 4,115,128, Tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used.

  As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 "-Trihydroxytriphenylmethane, 4,4 ', 3", 4 "-tetrahydroxy-3,5,3', 5'-tetramethyltriphenylmethane and the like.

  Further, examples of organic acids include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphate esters and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, p-toluenesulfinic acid, ethylsulfuric acid, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid Acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbine An acid etc. are mentioned. The proportion of the cyclic acid anhydride, phenols and organic acids in the composition is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably 0.1 to 10%. % By mass.

(Surfactant)
In the present invention, a nonionic surfactant as described in JP-A-62-251740 and JP-A-3-208514, JP-A-59-121044 is used in order to broaden the processing stability against development conditions. , Amphoteric surfactants as described in JP-A-4-13149, siloxane-based compounds as described in EP950517, JP-A-62-170950, JP-A-11-288093 A fluorine-containing monomer copolymer as described in Japanese Patent Application No. 2001-247351 can be added.

  The image forming layer can be obtained by applying and drying an image forming layer coating solution on a support.

  That is, the image forming layer is formed by applying and drying an image forming layer coating solution containing each of the above components contained in the image forming layer on a support, thereby producing a lithographic printing plate material.

(Support)
The support according to the present invention is a plate-like body that can carry the image forming layer, and an aluminum support is preferably used.

  The aluminum support is a pure aluminum plate or an aluminum alloy plate.

  Various aluminum alloys can be used, for example, alloys of aluminum and metals such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, etc. An aluminum plate produced by the method can be used. In addition, a recycled aluminum plate obtained by rolling recycled aluminum ingots such as scrap materials and recycled materials that are becoming popular in recent years can also be used.

  The aluminum support preferably has a roughened surface. Prior to roughening (graining treatment), it is preferable to perform a degreasing treatment in order to remove the rolling oil on the surface. As the degreasing treatment, a degreasing treatment using a solvent such as trichlene or thinner, an emulsion degreasing treatment using an emulsion such as kesilon or triethanol, or the like is used. In addition, an alkaline aqueous solution such as caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, dirt and oxide film that cannot be removed only by the degreasing treatment can be removed. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, smut is generated on the surface of the support. In this case, the substrate is immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof and desmutted. It is preferable to perform the treatment.

  Next, a roughening process is performed. Examples of the roughening method include a mechanical method and a method of etching by electrolysis. In the present invention, AC electrolytic surface roughening treatment in an electrolytic solution mainly composed of hydrochloric acid is preferable, but prior to that, mechanical surface roughening treatment and electrolytic surface roughening treatment mainly composed of nitric acid may be performed.

Following the roughening treatment, an anodizing treatment is performed to form an anodized film. The anodizing method is preferably carried out using sulfuric acid or an electrolytic solution mainly composed of sulfuric acid as the electrolytic solution. The concentration of sulfuric acid is preferably 5 to 50% by mass, particularly preferably 10 to 35% by mass. The temperature is preferably 10 to 50 ° C. The treatment voltage is preferably 18 V or more, and more preferably 20 V or more. Current density is preferably 1~30A / dm ^2. Electrical weight is preferably 200~600C / dm ^2.

  The anodized support may be sealed as necessary. These sealing treatments can be performed using known methods such as hot water treatment, boiling water treatment, water vapor treatment, sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, and ammonium acetate treatment.

<Hydrophilic treatment>
The aluminum support is preferably subjected to a hydrophilization treatment after the above treatment from the viewpoint of chemical resistance and sensitivity.

  Hydrophilization treatment is not particularly limited, but water-soluble resins such as phosphonic acids having amino groups such as polyvinylphosphonic acid, polyvinyl alcohol and derivatives thereof, carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and sulfonic acid Polymers and copolymers having a group in the side chain, polyacrylic acid, a water-soluble metal salt (for example, zinc borate), or a primer coated with a yellow dye, an amine salt, or the like can be used.

  Furthermore, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A-5-304358 is covalently used. It is preferable to perform a hydrophilic treatment with an aqueous solution containing polyvinylphosphonic acid.

  The treatment is not limited to a coating method, a spray method, a dip method, or the like, but a dip method is suitable for making the equipment inexpensive. In the case of a dip type, it is preferable to treat polyvinylphosphonic acid with a 0.05 to 3% aqueous solution. The treatment temperature is preferably 20 to 90 ° C., and the treatment time is preferably 10 to 180 seconds. After the treatment, it is preferable to perform a squeegee treatment or a water washing treatment in order to remove the excessively laminated polyvinylphosphonic acid. Furthermore, it is preferable to perform a drying process.

  As drying temperature, 40-180 degreeC is preferable, More preferably, it is 50-150 degreeC. The drying treatment is preferable because the adhesion to the lower layer and the function as a heat insulating layer are improved, and the chemical resistance and sensitivity are improved.

  The thickness of the hydrophilic treatment layer is preferably 0.002 to 0.1 μ, more preferably 0.005 to 0.05 μ from the viewpoints of adhesiveness, heat insulation, and sensitivity.

(Development processing)
The preparation method of the lithographic printing plate of the present invention is carried out with a developer having a pH of 2 to 10 at 25 ° C.

  When the pH of the developer is used in the range of 2 to 6, it is adjusted by adding a mineral acid, organic acid or inorganic salt to the developer. The addition amount is preferably 0.01 to 2% by mass. Examples of mineral acids include nitric acid, sulfuric acid, phosphoric acid, and metaphosphoric acid.

  Examples of the organic acid include citric acid, acetic acid, succinic acid, malonic acid, p-toluenesulfonic acid, tartaric acid, malic acid, lactic acid, levulinic acid, phytic acid, and organic phosphonic acid.

  Further, examples of the inorganic salt include magnesium nitrate, primary sodium phosphate, secondary sodium phosphate, nickel sulfate, sodium hexamethanoate, sodium tripolyphosphate, and the like. You may use together at least 1 sort (s) or 2 or more types, such as a mineral acid, an organic acid, or an inorganic salt.

  When used in the basic region pH 8 to 10, the pH can be adjusted by adding a water-soluble organic base or inorganic base. A water-soluble organic base is preferable, and examples include triethanolamine, diethanolamine, and ethanolamine.

  The developer may contain a water-soluble resin and a surfactant.

  Examples of water-soluble resins include gum arabic, fiber derivatives (for example, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.) and modified products thereof, polyvinyl alcohol and derivatives thereof, polyvinyl pyrrolidone, polyacrylamide and copolymers thereof, vinyl methyl ether / Examples thereof include a maleic anhydride copolymer, a vinyl acetate / maleic anhydride copolymer, and a styrene / maleic anhydride copolymer. The content of these water-soluble resins is suitably 0.1 to 50% by mass, more preferably 0.5 to 3.0% by mass in the developer.

  Examples of the surfactant include an anionic surfactant and a nonionic surfactant. Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates. Alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, polyoxyethylene aryl ether sulfonates, polyoxyethylene naphthyl ether sulfonates, N-methyl-N-oleyl taurine sodium, N -Alkylsulfosuccinic acid monoamide disodium salts, petroleum sulfonates, nitrated castor oil, sulfated beef oil, sulfate esters of fatty acid alkyl esters, alkyl Acid ester salts, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphate esters, polyoxyethylene alkyl ether phosphates Ester salts, polyoxyethylene alkylphenyl ether phosphate ester salts, partially saponified products of styrene-maleic anhydride copolymer, partially saponified products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensates, etc. Is mentioned. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene aryl ethers, polyoxyethylene naphthyl ether, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxy Propylene alkyl ether, glycerin fatty acid partial ester, sorbitan fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol mono fatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid moiety Esters, polyethylene glycol fatty acid esters, polyglycerol fatty acid partial esters, polyoxyethylenated ester List oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, etc. It is done. Of these, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene-polyoxypropylene block polymers and the like are preferably used.

  Fluorine-based and silicon-based anions and nonionic surfactants can also be used.

  Two or more of these surfactants can be used in combination. For example, two or more different from each other can be used in combination. For example, a combination of two or more different anionic surfactants or a combination of an anionic surfactant and a nonionic surfactant is preferable.

  A preservative, an antifoaming agent, etc. can be added to a developing solution.

  A chelate compound may be further added to the developer. Preferred chelate compounds include, for example, ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, sodium salt thereof; ethylenediamine disuccinic acid, potassium salt thereof. Triethylenetetramine hexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid, potassium salt thereof, sodium salt thereof: nitrilotriacetic acid, sodium salt thereof; 1-hydroxyethane-1,1-diphosphone Acids, potassium salts, sodium salts; organic phosphonic acids or phosphonoalkanetricarboxylic acids such as aminotri (methylenephosphonic acid), potassium salts, sodium salts, etc. It can be mentioned.

  In addition to the above components, a sensitizer such as turpentine oil can be added as necessary.

(Image exposure)
As a light source for image exposure according to the present invention, a laser light source having an emission wavelength in the infrared and near infrared regions can be used.

  Laser exposure is suitable for direct writing without using a mask material because light exposure can be performed in the form of a beam according to image data. When a laser is used as a light source, it is easy to reduce the exposure area to a very small size, and high-resolution image formation is possible.

  As the laser light source, a YAG laser, a semiconductor laser, or the like can be used, but it is particularly preferable to use a laser capable of continuous oscillation in a 700 to 1200 nm region.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the examples, “parts” represents “parts by mass” unless otherwise specified.

Example 1
<Production of support>
An aluminum plate (material 1050, tempered H16) having a thickness of 0.3 mm was immersed in a 5% aqueous sodium hydroxide solution maintained at 65 ° C., degreased for 1 minute, and then washed with water. This degreased aluminum plate was neutralized by immersing it in a 10% sulfuric acid aqueous solution maintained at 25 ° C. for 1 minute, and then washed with water.

Next, this aluminum plate was subjected to an electrolytic surface roughening treatment for 20 seconds in an alternating current having a hydrochloric acid concentration of 11 g / L, 25 ° C., a frequency of 50 Hz, and 50 A / dm ² . After electrolytic surface roughening, it was washed with water, desmutted for 10 seconds in a 1% aqueous sodium hydroxide solution kept at 50 ° C., washed with water, and then washed in 30% sulfuric acid kept at 50 ° C. for 30 seconds. The neutralization process was performed and it washed with water.

Next, anodization was performed for 30 seconds in a 30% sulfuric acid solution under the conditions of 25 ° C., current density of 30 A / dm ² , and voltage of 25 V, and washed with deionized water. Further, a 0.44% polyvinylphosphonic acid aqueous solution was dipped at 75 ° C. for 30 seconds, then washed with deionized water and dried with cold air at 25 ° C. to obtain a hydrophilically treated support. . The center line average roughness (Ra) of the surface of this support was 0.50 μm.

On the support, an image forming layer coating solution 1 having the following composition was applied using an extrusion coater to a dry film thickness of 1.3 g / m ² . The coating solvent was dried with hot air at 110 ° C. for 60 seconds to obtain a lithographic printing plate material (1).

<Image forming layer coating solution 1>
Novolak resin 1 (o-cresol / p-cresol = 70/30 (weight average molecular weight 10,000) 53.5 parts novolak resin 2 (m-cresol / p-cresol = 60/40 (weight average molecular weight 4,000) 22 parts Acrylic resin 1 (N- (4-hydroxyphenyl) maleimide / acrylonitrile / methyl methacrylate = 25/55/20 mol% weight average molecular weight 30,000)
8 parts acrylic resin 2 (P-hydroxyphenyl methacrylate / t-butoxycarbonylated-p-hydroxyphenyl methacrylate = 60/40 weight average molecular weight 30,000)
1 part polyethylene glycol (weight average molecular weight 4,000 2.5 parts sorbitan laurate 1 part phthalic anhydride 5 parts acid-decomposable compound (compound A below) 2 parts photothermal conversion dye (compound B below) 2 parts acid generator ( 2,4-trichloromethyl (4-methoxynaphthyl) -6-triazine)
0.5 parts Visible dye 1 (Oil Blue 613 (manufactured by Orient Chemical Co., Ltd.) 1.2 parts Visible dye 2 (Compound 1 below) 1.2 parts Fluorine-based compound (OMNOVA PolyFox 6520) 0.1 part γ- Butyrolactone 100 parts Cyclohexanone 130 parts Propylene glycol monomethyl ether 470 parts Methyl ethyl ketone 30 parts

  Next, in the preparation of the lithographic printing plate material (1), as shown in Table 1, the lithographic printing plate material (1) was changed except that the photothermal conversion dye or the acid generator was changed to the following organic particles 1 or organic particles 2. Lithographic printing plate materials (2) to (4) were produced in the same manner as in the production.

(Synthesis of organic particles (organic particles 1) chemically modified with an acid generator)
According to the method for synthesizing organic particles described in JP-A-55-22766, organic particles A having the following structure were synthesized.

  A solution obtained by dispersing 66 g of the organic particles in water and 26.8 g of 2,4-trichloromethyl (4-methoxynaphthyl) -6-triazine at 40 ° C. are stirred at a temperature of 40 ° C. The mixture was gradually added dropwise so as to maintain the temperature, and stirring was continued at the same temperature for 1 hour after the completion of the addition. This reaction solution was poured into 2.5 l of dilute hydrochloric acid (pH 1 to 3) to form a precipitate. The obtained precipitate was collected by suction filtration, washed with water and dried under reduced pressure to obtain (ion-binding) organic particles 1 chemically modified with an acid generator. The average particle size of the organic particles 1 was 0.6 μm.

(Synthesis of organic particles chemically modified with photothermal conversion dye (organic particles 2))
A solution obtained by dispersing 66 g of organic particles A in water and 10 g of a photothermal conversion dye (compound B below) are gradually added dropwise at 40 ° C. with stirring to 135 ml of 1N sodium carbonate so that the reaction solution maintains pH 7-8. After completion, stirring was continued at the same temperature for another hour. This reaction solution was poured into 2.5 l of dilute hydrochloric acid (pH 1 to 3) to form a precipitate. The obtained precipitate was collected by suction filtration, washed with water and dried under reduced pressure to obtain (ion-binding) organic particles 2 chemically modified with a photothermal conversion dye.

  The average particle diameter of the organic particles 2 was 0.08 μm.

  The lithographic printing plate materials (1) to (4) were evaluated as follows. The results are shown in Table 1.

<Evaluation>
(sensitivity)
The exposure energy of the laser at a resolution of 2400 dpi (dpi represents the number of dots per inch or 2.54 cm) using a lithographic printing plate material with a plate setter (Trendsetter 3244: manufactured by Creo) equipped with a light source of 830 nm After changing 100%, a 100% solid image was exposed, and then developed with Developer 1 having the following composition to obtain a lithographic printing plate. The density of each energy of the developed image is measured with a densitometer [D196: manufactured by GRETAG]. Sensitivity was defined as the amount of energy at which the density after development was the support density of the uncoated part +0.01.

<Developer 1> Finished pH = 13.1 (25 ° C.)
A 40% by weight aqueous solution of potassium silicate (containing 26.5% by weight SiO ₂ , 13.5% by weight K ₂ O) 87.8 parts 50% by weight aqueous potassium hydroxide 61.1 parts Surfactant (TrilonM (BASF) 40% solution) 1.4 parts water 896 parts

  It can be seen from Table 1 that a highly sensitive lithographic printing plate material can be obtained by using the chemically modified organic particles according to the present invention.

Example 2
Other than using the lithographic printing materials (1) to (4) prepared in Example 1 and using the following developer (pH of the developer is 4.5) instead of the developer used in Example 1. Prepared a lithographic printing plate in the same manner as in Example 1, and evaluated in the same manner as described above. The results are shown in Table 2.

<Developer 2>
100 g of water Sodium alkyl naphthalene sulfonate (Perex NB-L manufactured by Kao Corporation)
5 parts gum arabic 1 part primary ammonium phosphate 0.05 part citric acid 0.05 part ethylenediaminetetraacetate tetrasodium salt 0.05 part

  From Table 2, it can be seen that by using the chemically modified organic particles of the present invention, a highly sensitive lithographic printing plate material can be obtained without using an alkaline developer having a high environmental load and a high pH.

Example 3
An emulsion polymerization apparatus was prepared in which a stirring stirrer, 1 L addition funnel, thermometer, nitrogen gas injection tube, water-cooled condenser were installed in a 5 L 4-necked flask and placed in a heating mantle.

  To this flask was added 3360 g of deionized water and 20 g of a 30% aqueous solution of sodium lauryl sulfonate, and the solution was heated to 80 ° C. under a nitrogen atmosphere. At this temperature, 25% of a monomer mixture containing 220 g of methyl methacrylate, 240 g of ethyl acrylate, 165 g of methacrylic acid, 200 g of 2-hydroxyethyl methacrylate and 16 g of 1,4-butanediol diacrylate was added at once.

  To this was immediately added 10 ml of a 5% aqueous solution of potassium persulfate and 10 ml of a 7% aqueous solution of potassium phosphate. The reaction mixture became milky and exothermed to 85 ° C. The remainder of the monomer mixture was added over a period of 90 minutes while maintaining the temperature between 80-88 ° C. When the addition was complete, the reaction mixture was heated at 80-85 ° C. for an additional 2 hours. The bluish emulsion was cooled to room temperature and methanol was added to solidify. The resulting slurry was filtered, washed twice with water, sucked dry, and the resulting fine powder was dried in a 100 ° C. oven for 4 hours to obtain Particle B. The spherical shape of particle B was confirmed by a microscope.

  57 g of organic particles B and 24.2 g of 2,4-trichloromethyl (4-methoxynaphthyl) -6-triazine are added to water, and 135 ml of 1N sodium carbonate is maintained under stirring at 40 ° C., and the reaction solution maintains a pH of 7-8. The mixture was gradually added dropwise, and stirring was continued at the same temperature for another hour after the completion of the addition. This reaction solution was poured into 2.5 liters of dilute hydrochloric acid (pH 1 to 3) to form a precipitate. The resulting yellow precipitate was filtered, washed with water, dried under reduced pressure, and chemically modified with an acid generator (covalent bond). Organic particles 3 were obtained. The average particle size was 0.09 μm.

  Organic particles 4 were obtained in the same manner as described above except that 4-trichloromethyl (4-methoxynaphthyl) -6-triazine was changed to the compound B. The average particle size was 0.11 μm.

  Lithographic printing plate materials (5) to (8) were obtained in the same manner as in Example 1 except that the organic particles 3 and 4 were used. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 3.

  It can be seen from Table 3 that a highly sensitive lithographic printing plate material can be obtained by using the chemically modified organic particles according to the present invention.

Example 4
Evaluation was performed in the same manner as in Example 2 using the lithographic printing materials (5) to (8) prepared in Example 3 and using the developer used in Example 2 (the pH of the developer is 4.5). Went. The results are shown in Table 4.

  Table 4 shows that by using the chemically modified organic particles of the present invention, a highly sensitive lithographic printing plate material can be obtained without using an alkaline developer having a high environmental load and a high pH.

Claims (2)

A lithographic printing plate material comprising an image-forming layer containing an alkali-soluble resin and organic particles chemically modified with an acid generator or organic particles chemically modified with a photothermal conversion dye on a support. A method for preparing a lithographic printing plate, comprising subjecting the lithographic printing plate material according to claim 1 to image exposure and developing with a developer having a pH value of 2 to 10 at 25 ° C after the image exposure.