JP4864789B2 - Planographic printing plate precursor and laminate of planographic printing plate precursor - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor that can be directly drawn with a laser beam, and a laminate thereof.

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

As such a lithographic printing plate precursor capable of scanning exposure, an oleophilic photosensitive resin layer containing a photosensitive compound capable of generating active species such as radicals and Bronsted acids by laser exposure on a hydrophilic support (hereinafter referred to as “lithographic printing plate precursor”) , Also referred to as a recording layer) has been proposed and is already on the market. This lithographic printing plate precursor is laser-scanned based on digital information to generate active species, which causes a physical or chemical change in the recording layer to insolubilize it, followed by development processing, thereby developing a negative lithographic printing plate Can be obtained.
In particular, on a hydrophilic support, a photopolymerization type recording layer containing a photopolymerization initiator excellent in photosensitive speed, an addition-polymerizable ethylenically unsaturated compound, and a binder polymer soluble in an alkali developer, and necessary The lithographic printing plate precursor provided with an oxygen-blocking protective layer according to the above (for example, see Patent Document 1) is excellent in productivity, is easy to develop, and has good resolution and wearability. It has desirable printing performance.

On the other hand, shortening the time required for the exposure process is important as the productivity in the plate making operation of a photopolymerization type lithographic printing plate precursor that is easy to develop. In the exposure process, an adhesion preventing function between the original plates and a relatively soft photosensitive layer or a protective layer surface provided on the photosensitive layer are usually provided on the aluminum support or the back of the support between the original plates. It is supplied as a laminate in which a slip sheet having a function of preventing scratches caused by rubbing against the backcoat layer is inserted. Therefore, the slip sheet removal time in the exposure process has been a cause of inefficiency. In order to improve the efficiency in this exposure process, it is sufficient to omit the process of removing the slip sheet by using a laminate that does not insert the slip sheet between the master plates. There has been a desire for improvements in adhesion and scratches caused by rubbing the surface of the protective layer with the aluminum support.
The scratch referred to here means a scratch on the surface side (photosensitive layer or protective layer) of the lithographic printing plate precursor. If the non-image area is scratched, printing stains due to curing of the photosensitive layer, and scratches on the image area There is a big problem that image omission (white omission) or the like occurs when.
For improving such scratches, a method using a backcoat layer having a Tg of 20 ° C. or higher (for example, see Patent Document 2), a polyester resin, a phenoxy resin, or a polyvinyl acetal as a backcoat layer for a positive photosensitive layer. A method using a resin (for example, see Patent Document 3) is known, but further improvement is required.

From the above, there is a demand for a lithographic printing plate precursor that can improve the productivity in plate making operations by improving scratches caused by rubbing lithographic printing plate precursors when laminated without sandwiching interleaving paper. Currently.
Japanese Patent Laid-Open No. 10-228109 JP-A-6-332155 Japanese Patent Laid-Open No. 2005-62456

Therefore, the present invention has been made in view of the above problems, and an object thereof is to achieve the following object.
That is, an object of the present invention is to provide a lithographic printing plate precursor that can be written by laser exposure and that can prevent scratches between printing plates when they are laminated without sandwiching a slip sheet.
Another object of the present invention is to provide a laminate of a lithographic printing plate precursor capable of preventing rubbing scratches between printing plates and improving productivity in plate making operations.

As a result of intensive studies to solve the above problems, the present inventor uses a back coat layer containing an epoxy resin and at least one selected from the group consisting of a resin having a phenolic hydroxyl group and rosin . The present inventors have found that the above object can be achieved and have accomplished the present invention.
That is, the lithographic printing plate precursor of the present invention has a photosensitive recording layer on one side of a support, and an epoxy resin , a resin having a phenolic hydroxyl group, and a rosin on the other side of the support. It has the backcoat layer containing at least 1 sort (s) chosen, It is characterized by the above-mentioned.

In addition, it is a preferable aspect that the resin having a phenolic hydroxyl group contained in the back coat layer is a novolac resin or a pyrogallol resin.
Thus, when using resin which has a phenolic hydroxyl group for the backcoat layer in this invention, it is preferable that the content is 0.1-50 mass% with respect to the total mass of a backcoat layer. More preferably, it is 5-30 mass%.

Moreover, it is a preferable aspect that the rosin contained in the back coat layer is a rosin-modified phenol resin or a rosin ester.

In the lithographic printing plate precursor according to the invention, the photosensitive recording layer contains a sensitizing dye, a polymerization initiator, a polymerizable compound, and a binder polymer, and a protective layer having an oxygen barrier property on the photosensitive recording layer. The structure having is preferable.
This protective layer preferably contains a filler.

In the present invention, the photosensitive recording layer has an infrared absorber, a polymerization initiator, a monomer having two or more phenyl groups substituted with vinyl groups in the molecule, and a phenyl group substituted with vinyl groups in the side chain. It is a preferable aspect that it is the thing containing a polymer.
In another preferred embodiment, the photosensitive recording layer contains a binder polymer containing an allyl group of 0.7 meq / g to 8.0 meq / g.

  The laminate of the lithographic printing plate precursor according to the present invention is formed by laminating a plurality of the lithographic printing plate precursors according to the present invention by directly contacting the outermost surface on the photosensitive recording layer side and the outermost surface on the backcoat layer side. It is characterized by that.

According to the present invention, it is possible to provide a lithographic printing plate precursor that can be written by laser exposure and that can prevent scratches between printing plates when they are laminated without sandwiching interleaf paper.
In addition, according to the present invention, by using the planographic printing plate precursor of the present invention, it is possible to provide a laminate of a planographic printing plate precursor that can prevent rubbing scratches between printing plates and improve productivity in plate making operations. Can do.

<Lithographic printing plate precursor>
The lithographic printing plate precursor according to the invention has a photosensitive recording layer on one side of the support, and is selected from the group consisting of an epoxy resin , a resin having a phenolic hydroxyl group, and rosin on the other side of the support. A back coat layer containing at least one kind is provided.
Hereinafter, the constituent elements of the support, the photosensitive recording layer, and the backcoat layer constituting the lithographic printing plate precursor according to the invention will be described.

[Back coat layer]
The back coat layer used in the present invention must contain an epoxy resin and at least one selected from the group consisting of a resin having a phenolic hydroxyl group and rosin . Moreover, in order to improve various characteristics, you may use together other resin and an additive.
Hereinafter, the backcoat layer in the present invention will be described in detail.

(Epoxy resin)
Examples of the epoxy resin used for the back coat layer in the present invention include a glycidyl ether compound obtained by a reaction of polyhydric alcohol, polyhydric phenol, etc. with epichlorohydrin or a prepolymer thereof, and further a polymer of acrylic acid or glycidyl methacrylate. Examples thereof include a polymer or a copolymer.

  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, diglycidyl ether of hydrogenated bisphenol A , Hydroquinone diglycidyl ether, resorcinol diglycidyl ether, diglycidyl ether or epichlorohydrin polyadduct of bisphenol A, diglycidyl ether or epichlorohydrin polyadduct of bisphenol F, diglycidyl ether of halogenated bisphenol A Or epichlorohydrin polyadduct, diglycidyl ether of biphenyl type bisphenol or epichloro Dorin polyadducts, 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, jER1001 (molecular weight of about 900, epoxy equivalent of 450 to 500), jER1002 (molecular weight of about 1600, epoxy equivalent of 600 to 700), and jER1004 (molecular weight of about 1060) manufactured by Japan Epoxy Resins Co., Ltd. , Epoxy equivalent 875-975), jER1007 (molecular weight about 2900, epoxy equivalent 2000), jER1009 (molecular weight about 3750, epoxy equivalent 3000), jER1010 (molecular weight about 5500, epoxy equivalent 4000), jER1100L (epoxy equivalent 4000), jERYX31575 ( Epoxy equivalent 1200), Sumitomo Chemical Co., Ltd. Sumiepoxy ESCN-195XHN, ESCN-195X1, ESCN-195XF, etc. can be mentioned.

  The weight average molecular weight of the epoxy resin in the present invention is preferably 1000 or more in terms of polystyrene. More preferably, the weight average molecular weight is 1,000 to 500,000, still more preferably 1,000 to 200,000, and particularly preferably 1,000 to 100,000.

  The content of the epoxy resin in the backcoat layer in the present invention is the same as that when laminated without sandwiching the interleaf, from the viewpoint of preventing scratches and preventing slippage between the plates, with respect to the total mass of the backcoat layer. Thus, the range is preferably 50 to 100% by mass, more preferably 65 to 99% by mass, and still more preferably 70 to 97.5% by mass.

(Other resins)
The backcoat layer in the invention, in addition to epoxy resin, Ru using at least one selected from the group consisting of resin and rosin having a phenolic hydroxyl group.
Hereinafter, a resin having a phenolic hydroxyl group and a rosin that are suitably used for the backcoat layer in the present invention will be described. Note that both the resin having a phenolic hydroxyl group and rosin may be contained in the back coat layer.

-Resin having phenolic hydroxyl group-
Examples of the resin having a phenolic hydroxyl group that can be used in the present invention include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, m− / Novolak resin such as polycondensation polymer of p-mixed cresol and formaldehyde, phenol and cresol (any of m-, p-, or m- / p-mixed) and formaldehyde, pyrogallol and acetone The pyrogallol resin which is a condensation polymer with can be mentioned.

Moreover, the copolymer which copolymerized the compound which has a phenolic hydroxyl group can also be used as resin which has a phenolic hydroxyl group.
Here, examples of the compound having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenolic hydroxyl group.

  The weight average molecular weight of the resin having a phenolic hydroxyl group in the present invention is preferably 1000 or more in terms of polystyrene from the viewpoint of film properties. More preferably, the weight average molecular weight is 1,000 to 500,000, still more preferably 1,000 to 200,000, and particularly preferably 1,000 to 100,000.

  The content of the resin having a phenolic hydroxyl group in the present invention in the back coat layer is 0 with respect to the total mass of the back coat layer from the viewpoint of film property and adhesion resistance to the outermost surface on the photosensitive recording layer side. 0.1 to 90% by mass is preferable, 0.1 to 50% by mass is more preferable, and 0.5 to 30% by mass is even more preferable.

-Rosin-
Examples of the rosin used in the present invention include natural rosins such as gum rosin, tall oil rosin and wood rosin; polymerized rosin derived from the natural rosin; obtained by disproportionating or hydrogenating the natural rosin or polymerized rosin. Stabilized rosin; and unsaturated acid-modified rosin obtained by adding unsaturated carboxylic acids to the natural rosin or polymerized rosin. The unsaturated acid-modified rosin includes, for example, maleic acid-modified rosin, maleic anhydride-modified rosin, fumaric acid-modified rosin, itaconic acid-modified rosin, crotonic acid-modified rosin, cinnamic acid-modified rosin, acrylic acid-modified rosin, Examples thereof include methacrylic acid-modified rosin and acid-modified polymerized rosin corresponding thereto.
Among such rosins, rosin-modified phenolic resins or rosin esters are preferably used.

Examples of the rosin ester include super ester E-720, super ester E-730-55, super ester E-650, super ester E-786-60, tamanol E-100, emulsion AM-1002, emulsion SE-50 (and above). All trade names, special rosin ester emulsion, manufactured by Arakawa Chemical Industries, Ltd.), Super Ester L, Super Ester A-18, Super Ester A-75, Super Ester A-100, Super Ester A-115, Super Ester A- 125, Superester T-125 (all trade names, special rosin esters, manufactured by Arakawa Chemical Industries, Ltd.) and the like can be preferably used.
As rosin esters, ester gum AAG, ester gum AAL, ester gum A, ester gum AAV, ester gum 105, ester gum HS, ester gum AT, ester gum H, ester gum HP, ester gum HD, Pencel A, Pencel AD, Pencel AZ, Pencel C, Pencel D-125, Pencel D-135, Pencel D-160, Pencel KK (all trade names, rosin ester resins, manufactured by Arakawa Chemical Industries, Ltd.) are also preferably used. it can.

  Examples of the rosin-modified phenolic resin include Tamanol 135, Tamanol 145, Tamanol 340, Tamanol 350, Tamanol 351, Tamanol 352, Tamanol 353, Tamanol 354, Tamanol 359, Tamanol 361, Tamanol 362, Tamanol 366, Tamanol 374, and Tamanol. 379, Tamanoru 380, Tamanoru 381, Tamanoru 384, Tamanoru 386, Tamanoru 387, Tamanoru 388, Tamanoru 392, Tamanoru 394, Tamanoru 395, Tamanoru 396, Tamanoru 405, Tamanoru 406, Tamanoru 409, Tamanoru 410, Tamanoru 414, Tamanoru 415 All of the above can be preferably used as trade names, rosin-modified phenolic resins, manufactured by Arakawa Chemical Industries, Ltd.

  Furthermore, other rosins include Longis R, Longes K-25, Longis K-80, Longes K-18 (all trade names, rosin derivatives, manufactured by Arakawa Chemical Industries, Ltd.) Pine Crystal KR-85, Pine Crystal KR-612, Pine Crystal KR-614, Pine Crystal KE-100, Pine Crystal KE-311, Pine Crystal KE-359, Pine Crystal KE-604, Pine Crystal 30PX, Pine Crystal D-6011, Pine Crystal D-6154, Pine Crystal D-6240, Pine Crystal KM-1500, Pine Crystal KM-1550 (all trade names, ultra-light color rosin derivatives, manufactured by Arakawa Chemical Industries, Ltd.) and the like.

  The weight average molecular weight of rosin in the present invention is preferably 1000 or more in terms of polystyrene. More preferably, the weight average molecular weight is 1,000 to 500,000, still more preferably 1,000 to 200,000, and particularly preferably 1,000 to 100,000.

  The content of the rosin in the back coat layer in the present invention, when laminated without sandwiching the interleaving paper, from the viewpoint of preventing scratches and preventing slippage between the plates, relative to the total mass of the back coat layer 0 to 50% by mass, more preferably 1 to 35% by mass, and even more preferably 2.5 to 30% by mass.

(Other ingredients)
Furthermore, for the purpose of improving the film properties, the back coat layer may be added with an organic or inorganic polymer compound, or may have flexibility or adjust slip properties, and may be a plasticizer or a surfactant. Other additives can be added as necessary.

  Preferred polymer compounds include, for example, polybutene, polybutadiene, polyamide, unsaturated copolymerized polyester resin, polyurethane, polyurea, polyimide, polysiloxane, polycarbonate, chlorinated polyethylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, acrylic resin These copolymer resins, hydroxycellulose, polyvinyl alcohol, cellulose acetate, carboxymethylcellulose and the like are suitable.

  As these polymer compounds, those having a weight average molecular weight of 500 or more in terms of polystyrene are preferably used. More preferably, the weight average molecular weight is 1,000 to 500,000, still more preferably 1,000 to 200,000, and particularly preferably 1,000 to 100,000.

Preferred plasticizers used in the backcoat layer in the present invention include, for example, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, Phthalic acid esters such as diallyl phthalate, dimethyl glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, glycol esters such as triethylene glycol dicaprylate, tricresyl phosphate , Phosphate esters such as triphenyl phosphate, diisobutyl adipate, Ruajipeto, dimethyl sebacate, dibutyl sebacate, dioctyl azelate, aliphatic dibasic acid esters such as dibutyl maleate, polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, and butyl laurate is effective.
These plasticizers are added as long as the back coat layer is not sticky.

Preferred examples of the surfactant used in the back coat layer in the present invention include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers 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 partial ester , Polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, polyoxyethylenated castor oil, polyoxyethylene Nonionic surfactants such as glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, fatty acids Salts, abietates, hydroxyalkanesulfonates, alkanesulfonates, dialkylsulfosuccinates, linear alkylbenzenesulfonates, branched alkylbenzenesulfonates, alkylnaphthalenesulfonates, alkylphenoxypolyoxyethylenepropyl Sulfonates, polyoxyethylene alkylsulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkylsulfosuccinic acid monoamide dinatri Salts, petroleum sulfonates, sulfated beef oil, sulfates of fatty acid alkyl esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates , Polyoxyethylene styryl phenyl ether sulfate ester salts, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphate ester salts, polyoxyethylene alkyl phenyl ether phosphate ester salts, partially saponified products of styrene / maleic anhydride copolymer , Partially saponified products of olefin / maleic anhydride copolymer, naphthalenesulfonate formalin condensates, alkylamine salts, quaternary ammonium salts , Cationic surfactants such as polyoxyethylene alkylamine salts and polyethylene polyamine derivatives, and amphoteric surfactants such as carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfates, and imidazolines.
Among the surfactants listed above, those having polyoxyethylene can be read as polyoxyalkylenes such as polyoxymethylene, polyoxypropylene and polyoxybutylene, and these surfactants are also included.

  A more preferred surfactant is a fluorosurfactant containing a perfluoroalkyl group in the molecule. Such fluorosurfactants include perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, anionic types such as perfluoroalkyl phosphates, amphoteric types such as perfluoroalkyl betaines, and perfluoroalkyltrimethylammonium salts. Cationic and perfluoroalkyl amine oxides, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl group and hydrophilic group-containing oligomers, perfluoroalkyl group and lipophilic group-containing oligomers, perfluoroalkyl groups, hydrophilic groups and lipophilic groups Nonionic types such as group-containing oligomers, perfluoroalkyl groups, and lipophilic group-containing urethanes can be mentioned.

  Said surfactant can be used individually or in combination of 2 or more types, 0.001-10 mass% with respect to the total mass of a backcoat layer, More preferably, the range of 0.001-5 mass% Is added.

  The backcoat layer in the present invention further includes an o-naphthoquinone diazide compound, a photosensitive azide compound, a photopolymerizable composition containing an unsaturated double bond-containing monomer as a main component, and a photocrosslinking containing cinnamic acid or a dimethylmaleimide group. Chemical compounds and diazo resins obtained by condensing diazonium salt monomers and aromatic diazonium salts with reactive carbonyl group-containing organic condensing agents (especially aldehydes or acetals such as formaldehyde and acetaldehyde) in an acidic medium. It can be added for improvement. Of these, o-naphthoquinonediazide compounds known as positive photosensitive compounds are preferably used.

The back coat layer in the present invention can be provided by thermocompression bonding of a film, a melt lamination method, or a coating method, but coating from a solution is more preferable for efficiently providing a thin layer.
Therefore, in the present invention, the resin used for the back coat layer is preferably non-crystalline and easily soluble in various industrial organic solvents.
Solvents used in forming the backcoat layer include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, Propylene glycol monoethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethyleneglycol Monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, lactic acid Examples include methyl and ethyl lactate.
These solvents can be used alone or in combination. The concentration of the solid content in the backcoat layer forming coating solution is suitably 0.5 to 50% by mass.

In the present invention, the coating amount of the backcoat layer mainly affects the static friction coefficient and the generation of scratches, and it is desirable to select appropriately according to the application. If the coating amount is too small, the effect of generating a static friction coefficient and scratches on the backcoat layer becomes insufficient. On the other hand, when the amount is too large, the adhesion of the membrane to the support deteriorates and is not preferred because it peels off during handling.
The coverage of the backcoat layer, the mass after drying is preferably in the range of 0.01 to 10 g / ^{m 2,} more preferably in the range of 0.05~7g / ^{m 2,} of 0.1-5 g / ^{m 2} A range is more preferred.

In addition, when the planographic printing plate precursor of the present invention is laminated without interposing the interleaving paper, it is preferable to control the smoothness between the plates.
The sliding property between the plate materials can be determined by using the coefficient of static friction of the backcoat layer as an index. Specifically, in the lithographic printing plate precursor according to the invention, the static friction coefficient of the backcoat layer with respect to the outermost surface on the photosensitive recording layer side is preferably in the range of 0.35 to 1.00, and 0.40 to 1 More preferably, the range is 0.00. When the static friction coefficient is within this range, no slip occurs between the plate materials, and a stable laminate can be formed.
Moreover, since the friction between the plate materials can be reduced when the static friction coefficient is in the above range, the generation of scratches can be further suppressed.

(Photosensitive recording layer)
The lithographic printing plate precursor according to the invention has a photosensitive recording layer on the surface of the support opposite to the surface having the backcoat layer.
The photosensitive recording layer in the present invention may be a positive type or a negative type.
The positive photosensitive recording layer is not particularly limited as long as the exposed portion is developed and the unexposed portion becomes the recording portion (image portion). However, the recording layer using o-quinonediazide, Examples thereof include a recording layer using an amplification mechanism.
The negative photosensitive recording layer is not particularly limited as long as the exposed portion is cured to form a recording portion (image portion), but the polymerizable photosensitive layer having a radical polymerizable compound, acid crosslinkability Examples thereof include an acid-crosslinkable photosensitive layer having a substance.
In particular, the problem that the surface of the lithographic printing plate precursor is scratched is a negative type that causes stains on the printed matter by curing the scratched part, and the effect of the backcoat layer in the present invention is more remarkable. In particular, it is preferable that the photosensitive recording layer in the invention is a polymerizable negative photosensitive layer.
Hereinafter, a polymerizable negative photosensitive layer suitable as the photosensitive recording layer of the present invention will be described in detail.

(Polymerizable negative photosensitive layer)
The polymerizable negative photosensitive layer according to the present invention (hereinafter sometimes simply referred to as “photosensitive layer”) contains a sensitizing dye, a polymerization initiator, a polymerizable compound, and a binder polymer, and further if necessary. It is preferable that a colorant and other optional components are included.

Since the polymerizable negative photosensitive layer in the present invention is sensitive to a laser corresponding to a sensitizing dye, it can be exposed to various lasers useful for CTP. For example, in the case of using an infrared absorber as a sensitizing dye, the infrared absorber contained in the polymerizable negative photosensitive layer is highly sensitive to the irradiation (exposure) of an infrared laser and is in an electronically excited state. Electron transfer, energy transfer, heat generation (photothermal conversion function), and the like related to the electronically excited state act on the polymerization initiator coexisting in the photosensitive layer to cause a chemical change in the polymerization initiator to generate radicals.
In this case, the radical generation mechanism is as follows: 1. Heat generated by the photothermal conversion function of the infrared absorber thermally decomposes a polymerization initiator (for example, sulfonium salt) described later to generate radicals. 2. Excited electrons generated by the infrared absorber move to a polymerization initiator (for example, an active halogen compound) to cause radicals. For example, radicals are generated by electron transfer from a polymerization initiator (for example, a borate compound) to an excited infrared absorber. Then, the polymerizable compound causes a polymerization reaction by the generated radical, and the exposed portion is cured to become an image portion.

  The lithographic printing plate precursor of the above embodiment is particularly suitable for plate making directly drawn with an infrared laser beam having a wavelength of 750 nm to 1400 nm because the polymerizable negative photosensitive layer contains an infrared absorber as a sensitizing dye. In addition, it can exhibit high image-forming properties as compared with conventional lithographic printing plate precursors.

In the present invention, an infrared absorber, a polymerization initiator (a compound that generates radicals by light or heat), a monomer having two or more phenyl groups substituted with vinyl groups in the molecule, and a phenyl group substituted with vinyl groups A polymerizable negative photosensitive layer containing a polymer having a side chain is a preferred embodiment because of its high sensitivity.
Below, each component which comprises the polymeric negative photosensitive layer concerning this invention is demonstrated.

(Sensitizing dye)
The photosensitive layer according to the present invention contains a sensitizing dye that absorbs light having a predetermined wavelength that matches the exposure wavelength in laser exposure from the viewpoint of sensitivity.
The exposure of the wavelength that can be absorbed by the sensitizing dye accelerates the radical generation reaction of the polymerization initiator described later and the polymerization reaction of the polymerizable compound thereby. Examples of such a sensitizing dye include a known spectral sensitizing dye or dye, or a dye or pigment that absorbs light and interacts with a photopolymerization initiator. This sensitizing dye becomes a highly sensitive electron excited state by laser exposure at a wavelength suitable for the sensitizing dye, and electron transfer, energy transfer, etc. related to the electron excited state act on the polymerization initiator described later, and the polymerization initiator has a high level. It is useful for generating radicals by causing chemical changes with sensitivity.

  Depending on the wavelength of light absorbed by the sensitizing dye, the photosensitive layer in the present invention can be sensitive to various wavelengths from ultraviolet rays to visible rays and infrared rays. For example, when an infrared absorber is used as the sensitizing dye, it is sensitive to infrared light having a wavelength of 760 nm to 1200 nm. Further, by using a dye having a maximum absorption wavelength from 350 nm to 450 nm, it is sensitive to blue to purple visible light.

  Spectral sensitizing dyes or dyes preferred as sensitizing dyes used in the present invention are polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal). ), Cyanines (eg thiacarbocyanine, oxacarbocyanine), merocyanines (eg merocyanine, carbomerocyanine), thiazines (eg thionine, methylene blue, toluidine blue), acridines (eg acridine orange, chloroflavin) , Acriflavine), phthalocyanines (eg, phthalocyanine, metal phthalocyanine), porphyrins (eg, tetraphenylporphyrin, central metal-substituted porphyrin), chlorophylls (eg, chlorophyll) Chlorophyllin, central metal-substituted chlorophyll), metal complexes, anthraquinones (for example, anthraquinone), squalium (for example, squalium), and the like, for example, paragraph numbers [0188] to [0188] to [ [0258] can be selected as appropriate and used as a sensitizing dye in the present invention.

Among these, the photosensitive layer in the present invention preferably contains an infrared absorber described in detail below as a sensitizing dye.
Infrared absorbers are in an electronically excited state with high sensitivity to infrared laser irradiation (exposure), and heat energy is generated by the photothermal conversion function in addition to the electron transfer and energy transfer related to the previous electron excited state. It is useful for causing a chemical change with high sensitivity by a polymerization initiator.
As an infrared absorber which is a particularly preferable sensitizing dye used in the present invention, a dye or pigment having an absorption maximum at a wavelength of 750 nm to 1400 nm is preferably exemplified.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, 58-181690, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59- No. 73996, JP-A-60-52940, JP-A-60-63744 and the like, Naphthoquinone dyes described in JP-A-58-112792, etc., British Patent 434,875 And cyanine dyes.

Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. . Moreover, as another example preferable as a dye, the near-infrared absorptive dye described as the formula (I) and (II) in US Patent 4,756,993 can be mentioned.
Other preferable examples of the infrared absorbing dye in the present invention include specific indolenine cyanine dyes described in JP-A-2002-278057 as exemplified below.

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

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 1 carbon atom including a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.
In the group shown below, X _a ^- is Z _a which will be described below ^- has the same definition as, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom Represents.

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

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

Specific examples of the cyanine dye represented by formula (a) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. Can do.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.
However, a counter ion that does not contain a halogen ion is particularly preferable.

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

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

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

  The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. Within this preferred particle size range, excellent dispersion stability of the pigment in the photosensitive layer can be obtained, and a uniform photosensitive layer can be obtained.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  When these infrared absorbers are used in the photosensitive layer according to the present invention, they may be added to the same layer as other components, or another layer may be provided and added thereto.

  The addition amount of these sensitizing dyes, preferably infrared absorbers, is 0.01 to 50% by mass with respect to the total solid content constituting the photosensitive layer from the viewpoint of uniformity in the photosensitive layer and durability of the photosensitive layer. It is preferably in the range of 0.1 to 10% by mass, particularly preferably 0.5 to 10% by mass when a dye is used as a sensitizing dye, and particularly when a pigment is used. Preferably it can add in the ratio of 0.1-10 mass%.

(Polymerization initiator)
The polymerization initiator used in the present invention has a function of initiating and advancing the curing reaction of a polymerizable compound described later, and is a thermal decomposition type radical generator that decomposes by heat to generate radicals, and excitation of an infrared absorber. Energy (for example, heat or light) such as an electron transfer type radical generator that accepts electrons to generate radicals, or an electron transfer type radical generator that generates electrons by transferring electrons to an excited infrared absorber. Any compound may be used as long as it generates radicals by imparting. For example, onium salts, active halogen compounds, oxime ester compounds, borate compounds and the like can be mentioned. These may be used in combination. In the present invention, an onium salt is preferable, and a sulfonium salt is particularly preferable.
Examples of the sulfonium salt polymerization initiator suitably used in the present invention include onium salts represented by the following general formula (I).

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

  Specific examples ([OS-1] to [OS-13]) of the onium salt represented by the general formula (I) are shown below, but are not limited thereto.

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

  In the present invention, in addition to the sulfonium salt polymerization initiator, other polymerization initiators (other radical generators) can be used. Other radical generators include onium salts other than sulfonium salts, triazine compounds having a trihalomethyl group, peroxides, azo polymerization initiators, azide compounds, quinonediazides, active halogen compounds, oxime ester compounds, triaryls. Examples thereof include monoalkyl borate compounds. Among them, onium salts are preferable because of their high sensitivity. Moreover, these polymerization initiators (radical generators) can be used in combination with the sulfonium salt polymerization initiator as an essential component.

Other onium salts that can be suitably used in the present invention include iodonium salts and diazonium salts. In the present invention, these onium salts function not as acid generators but as radical polymerization initiators.
Other onium salts in the present invention include onium salts represented by the following general formulas (II) and (III).

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

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

  In the present invention, an onium salt represented by the general formula (II) ([OI-1] to [OI-11]) and an onium salt represented by the general formula (III) ([ Specific examples of ON-1] to [ON-5] are given below, but are not limited thereto.

  Specific examples of onium salts that can be suitably used as a polymerization initiator (radical generator) in the present invention include those described in JP-A No. 2001-133696.

  In the present invention, an organic boron salt or a trihaloalkyl-substituted compound is preferably used as the polymerization initiator. More preferably, an organic boron salt and a trihaloalkyl-substituted compound are used in combination. A combination of an organic boron salt and an onium salt is also preferably used.

  The organoboron anion constituting the organoboron salt is represented by the following general formula (1).

In the general formula (1), R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may be the same or different, and may be an alkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, or a cycloalkyl group. Represents a heterocyclic group. Of these, it is particularly preferred that one of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ is an alkyl group and the other substituent is an aryl group.

The above-mentioned organoboron anion is present simultaneously with the cation forming a salt with the anion. Examples of the cation in this case include alkali metal ions, onium ions, and cationic sensitizing dyes.
Examples of the onium ions include ammonium ions, sulfonium ions, iodonium ions, and phosphonium ions.
When using a salt of an organic boron anion and an alkali metal ion or onium ion as the organic boron salt, adding a sensitizing dye separately to impart photosensitivity in the wavelength range of light absorbed by the dye. Is done. Further, when a salt having an organic boron anion as a counter anion of a cationic sensitizing dye is used as the organic boron salt, photosensitivity is imparted according to the absorption wavelength of the cationic sensitizing dye. However, in the latter case, it is preferable to further contain a salt of an alkali metal ion or onium ion and an organic boron anion.

The organic boron salt used in the present invention is a salt containing an organic boron anion represented by the general formula (1), and alkali metal ions and onium ions are preferably used as cations forming the salt. Particularly preferred examples are salts of organic boron anions and onium ions, specifically, ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and phosphonium salts such as triarylalkylphosphonium salts. Can be mentioned.
Specific examples (BC-1) to (BC-6) of particularly preferred organic boron salts are shown below.

  The trihaloalkyl-substituted compound used in the present invention is specifically a compound having at least one trihaloalkyl group such as a trichloromethyl group or tribromomethyl group in the molecule. Examples of the compound in which the group is bonded to the nitrogen-containing heterocyclic group include s-triazine derivatives and oxadiazole derivatives, or the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocyclic ring via a sulfonyl group. And haloalkylsulfonyl compounds.

  Particularly preferred specific examples (T-1) to (T-15) of compounds in which a trihaloalkyl group is bonded to a nitrogen-containing heterocyclic group, and particularly preferred specific examples (BS-1) to (BS-) of trihaloalkylsulfonyl compounds. 10) is shown below.

  In the present invention, an organic peroxide can also be used as a polymerization initiator. Examples of the organic peroxide include cumene hydroperoxide, tert-butyl hydroperoxide, dichloroperoxide, di-tert-butyl peroxide, benzoyl peroxide, acetyl peroxide, lauroyl peroxide, and compounds having the structure shown below. Is mentioned.

  The polymerization initiator (radical generator) used in the present invention preferably has a maximum absorption wavelength of 400 nm or less, and more preferably 360 nm or less. By making the absorption wavelength in the ultraviolet region in this way, the lithographic printing plate precursor can be handled under white light.

  The total content of the polymerization initiator in the present invention is 0.1 to 50% by mass, preferably 0. 0% by mass with respect to the total solid content constituting the photosensitive layer, from the viewpoint of sensitivity and generation of stains in the non-image area during printing. It is 5-30 mass%, Most preferably, it is 1-20 mass%.

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

  When a highly sensitive sulfonium salt polymerization initiator, which is preferable as a polymerization initiator, is used for the photosensitive layer in the present invention, the radical polymerization reaction proceeds effectively, and the strength of the formed image portion becomes very high. Therefore, combined with the high oxygen blocking function of the protective layer described later, a lithographic printing plate having high image area strength can be produced, and as a result, printing durability is further improved. In addition, since the sulfonium salt polymerization initiator itself is excellent in stability over time, even when the produced lithographic printing plate precursor is stored, the occurrence of an undesirable polymerization reaction is effectively suppressed. Will also have.

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

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

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

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

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

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

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

^{_{CH 2 = C (R a)}} COOCH 2 CH (R b) OH ··· formula (IV)
(However, R ^a and R ^b represent H or CH _3. )

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

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

As the polymerizable compound in the present invention, a monomer having two or more phenyl groups substituted with vinyl groups (hereinafter, appropriately referred to as a specific monomer) can also be preferably used.
In order to effectively perform crosslinking by recombination of styryl radicals generated by radicals generated from the above-described polymerization initiator (radical generator), the inclusion of this component makes it highly sensitive and does not require heat treatment. Type photosensitive layer.
The specific monomer in the present invention is typically a compound represented by the following general formula (3).

In General Formula (3), Z ² represents a linking group, and R ²¹ , R ²² , and R ²³ are each independently a hydrogen atom, a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, or an amide group. An amino group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, and the like, and these groups are substituted with an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, a hydroxy group, and the like. It may be. R ²⁴ represents a substitutable group or atom. m ² represents an integer of 0 to 4, and k ² represents an integer of 2 or more.

The compound represented by the general formula (3) will be described in more detail. As the linking group for Z ² , an oxygen atom, a sulfur atom, an alkylene group, an alkenylene group, an arylene group, —N (R ⁵ ) —, —C (O) —O—, —C (R ⁶ ) ═N—, Examples include —C (O) —, a sulfonyl group, a heterocyclic structure, a benzene ring structure, or a group in which two or more are combined. Here, R ⁵ and R ⁶ represent a hydrogen atom, an alkyl group, an aryl group, or the like. Furthermore, the above-described linking group may have a substituent such as an alkyl group, an aryl group, or a halogen atom.

The heterocyclic structure constituting the linking group represented by Z ² includes pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring , Thiadiazole ring, thiatriazole ring, indole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring , Triazine ring, quinoline ring, quinoxaline ring and the like nitrogen-containing heterocycle, furan ring, thiophene ring, etc., and these heterocyclic structures further include alkyl groups, amino groups, aryl groups, alkenyl groups, carboxy groups, sulfo groups. Group, hydroxy It may have a substituent such as a group.

The substitutable group or atom represented by R ²⁴ includes a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, and an aryloxy group. Furthermore, these groups or atoms may have a substituent such as an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, or a hydroxy group.

Among the compounds represented by the general formula (3), those having the structure shown below are preferable. That is, in the general formula (3), R ²¹ and R ²² are hydrogen atoms, R ²³ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.), and k ² is an integer of 2-10. Is preferred.

  Specific examples (C-1) to (C-11) of the compound represented by the general formula (3) are shown below, but are not limited to these specific examples.

About these addition polymerizable compounds, the details of usage, such as the structure, single use or combined use, and addition amount can be arbitrarily set according to the final performance design. For example, it is selected from the following viewpoints. From the viewpoint of photosensitive speed, a structure having a high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image portion, that is, the cured film, those having three or more functionalities are preferable, and furthermore, different functional numbers and different polymerizable groups (for example, acrylic ester, methacrylic ester, styrenic compound, A method of adjusting both photosensitivity and strength by using a vinyl ether compound) is also effective. A compound having a large molecular weight or a compound having high hydrophobicity is excellent in photosensitive speed and film strength, but is not preferable in terms of development speed and precipitation in a developer. In addition, the selection and use method of the addition polymerization compound is also an important factor for the compatibility and dispersibility with other components constituting the photosensitive layer (for example, binder polymer, polymerization initiator, colorant, etc.). For example, the compatibility may be improved by using a low-purity compound or using two or more kinds in combination.
In the lithographic printing plate precursor according to the invention, a specific structure may be selected for the purpose of improving adhesion to a support or a protective layer described later.

With respect to the content of the addition polymerizable compound in the photosensitive layer, the sensitivity, the occurrence of phase separation, the adhesiveness of the photosensitive layer, and the solid content in the photosensitive layer from the viewpoint of precipitation from the developer, Preferably it is 5-80 mass%, More preferably, it is used in 40-75 mass%.
The addition polymerizable compounds may be used alone or in combination of two or more. In addition, as for the method of using the addition polymerizable compound, an appropriate structure, blending, and addition amount can be arbitrarily selected from the viewpoints of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface tackiness, and the like. Furthermore, in the lithographic printing plate precursor according to the invention, a layer constitution / coating method such as undercoating or overcoating can be carried out.

(Binder polymer)
The binder polymer used in the present invention is contained from the viewpoint of improving the film property, and various types can be used as long as it has a function of improving the film property.

-Specific binder polymer (1)-
Examples of the binder polymer suitable in the present invention include binder polymers having a repeating unit represented by the following general formula (i).
Hereinafter, the binder polymer having the repeating unit represented by the general formula (i) is appropriately referred to as a specific binder polymer (1) and will be described in detail.

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

First, R ¹ in the general formula (i) represents a hydrogen atom or a methyl group, and a methyl group is particularly preferable.

The linking group represented by R ² in the general formula (i) includes two or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. The number is 2 to 82, preferably 2 to 50, and more preferably 2 to 30. The total number of atoms shown here refers to the number of atoms including the substituent when the linking group has a substituent. More specifically, the number of atoms constituting the main skeleton of the linking group represented by R ² is preferably 1-30, more preferably 3-25, and 4-20. More preferred is 5-10. The “main skeleton of the linking group” in the present invention refers to an atom or an atomic group used only for linking A and the terminal COOH in the general formula (i), and particularly when there are a plurality of linking paths. Refers to an atom or atomic group that constitutes a path with the least number of atoms used. Therefore, when a linking group has a ring structure, the number of atoms to be included differs depending on the linking site (for example, o-, m-, p-, etc.).

More specific examples include alkylene, substituted alkylene, arylene, substituted arylene, and the like, and a structure in which a plurality of these divalent groups are linked by an amide bond or an ester bond may be used.
Examples of the linking group having a chain structure include ethylene and propylene. A structure in which these alkylenes are linked via an ester bond can also be exemplified as a preferable example.

Among these, the linking group represented by R ² in the general formula (i) is preferably an (n + 1) -valent hydrocarbon group having an aliphatic cyclic structure having 3 to 30 carbon atoms. More specifically, a compound having an aliphatic cyclic structure such as cyclopropane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, dicyclohexyl, tercyclohexyl, norbornane and the like, which may be substituted by one or more arbitrary substituents And (n + 1) valent hydrocarbon groups by removing (n + 1) hydrogen atoms on an arbitrary carbon atom constituting. R ² preferably has 3 to 30 carbon atoms including a substituent.

One or more arbitrary carbon atoms of the compound constituting the aliphatic cyclic structure may be replaced with a heteroatom selected from a nitrogen atom, an oxygen atom, or a sulfur atom. In terms of printing durability, R ² is a condensed polycyclic aliphatic hydrocarbon, a bridged cyclic aliphatic hydrocarbon, a spiro aliphatic hydrocarbon, an aliphatic hydrocarbon ring assembly (a plurality of rings are connected by a bond or a linking group). A (n + 1) valent hydrocarbon group having an aliphatic cyclic structure which may have a substituent of 5 to 30 carbon atoms containing two or more rings. . Also in this case, the carbon number includes the carbon atom of the substituent.

As the linking group represented by R ² , those having 5 to 10 atoms constituting the main skeleton of the linking group are particularly preferable, and are structurally a chain structure, and an ester bond in the structure. And those having a cyclic structure as described above are preferred.

Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups. Group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N- Diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy Group, arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′- Arylureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N-arylureido group, N′-alkyl-N-alkylureido group, N '-Alkyl-N-arylureido group, N', N'-dialkyl-N-alkylureido group, N ', N'-dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N '-Aryl-N-arylureido group, N', N'-diaryl-N-alkylureido group, N ', N'-diaryl-N-arylureido group, N'-a Kill-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl group and its conjugate base group, Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, Alkylsulfinyl , An arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfo group (-SO 3 _H) and its conjugated base group, alkoxy sulfonyl group, aryloxy sulfonyl group, sulfinamoyl group, N- alkylsulfinamoyl group, N, N -Dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, N-acylsulfamoyl group and its conjugate base group , N- alkylsulfonylsulfamoyl group _(-SO 2 NHS ₂ (alkyl)) and its conjugated base group, N- aryl sulfonylsulfamoyl group _{(-SO 2 NHSO 2 (aryl)} ) and its conjugated base group, N- alkylsulfonylcarbamoyl group _(-CONHSO 2 _(alkyl)) and Its conjugated base group, N-arylsulfonylcarbamoyl group (—CONHSO ₂ (aryl)) and its conjugated base group, alkoxysilyl group (—Si (Oalkyl) ₃ ), aryloxysilyl group (—Si (Oaryl) ₃ ), Hydroxysilyl group (—Si (OH) ₃ ) and its conjugate base group, phosphono group (—PO ₃ H ₂ ) and its conjugate base group, dialkylphosphono group (—PO ₃ (alkyl) ₂ ), diarylphosphono group (—PO ₃ (aryl) ₂ ), alkylarylphosphono group (—PO ₃ (a lkyl) (aryl)), monoalkylphosphono group (—PO ₃ H (alkyl)) and its conjugate base group, monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group, phosphonooxy group ( -OPO ₃ H ₂₎ and its conjugated base group, a dialkyl phosphono group _{(-OPO 3 (alkyl) 2)} , diaryl phosphono group _{(-OPO 3 (aryl) 2)} , alkylaryl phosphono group (- _{OPO 3 (alkyl) (aryl)} ), monoalkyl phosphono group _(-OPO 3 H _(alkyl)) and its conjugated base group, monoarylphosphono group _(-OPO 3 H _(aryl)) and its conjugate base group, a cyano group, a nitro group, a dialkyl boryl group (-B _{(alkyl) 2),} Jiariruboriru group (-B ( _RYL) 2), alkyl aryl boryl group (-B (alkyl) (aryl) ), dihydroxy boryl group (-B _{(OH) 2)} and its conjugated base group, an alkyl hydroxy boryl group (-B (alkyl) (OH) ) And its conjugated base group, arylhydroxyboryl group (-B (aryl) (OH)) and its conjugated base group, aryl group, alkenyl group and alkynyl group.

  In the lithographic printing plate precursor according to the invention, although depending on the design of the photosensitive layer, a substituent having a hydrogen atom capable of hydrogen bonding, particularly a substituent having an acid dissociation constant (pKa) smaller than that of a carboxylic acid is , Because it tends to lower the printing durability. On the other hand, hydrophobic substituents such as halogen atoms, hydrocarbon groups (alkyl groups, aryl groups, alkenyl groups, alkynyl groups), alkoxy groups, aryloxy groups and the like are more preferable because they tend to improve printing durability. When the cyclic structure is a monocyclic aliphatic hydrocarbon having 6 or less members such as cyclopentane or cyclohexane, it preferably has such a hydrophobic substituent. If possible, these substituents may be bonded to each other or with a substituted hydrocarbon group to form a ring, and the substituent may be further substituted.

R ³ in the case where A in the general formula (i) is NR ³ — represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ³ include an alkyl group, an aryl group, an alkenyl group, and an alkynyl group.
Specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, isopropyl group, isobutyl group, sec-butyl group, 1 carbon number such as tert-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-norbornyl group Up to 10 linear, branched or cyclic alkyl groups.
Specific examples of the aryl group include carbon having one heteroatom selected from the group consisting of an aryl group having 1 to 10 carbon atoms such as a phenyl group, a naphthyl group, and an indenyl group, a nitrogen atom, an oxygen atom, and a sulfur atom. Examples include heteroaryl groups of 1 to 10, such as furyl, thienyl, pyrrolyl, pyridyl, and quinolyl groups.
Specific examples of the alkenyl group include those having 1 to 10 carbon atoms such as vinyl group, 1-propenyl group, 1-butenyl group, 1-methyl-1-propenyl group, 1-cyclopentenyl group, 1-cyclohexenyl group and the like. A linear, branched, or cyclic alkenyl group is mentioned.
Specific examples of the alkynyl group include alkynyl groups having 1 to 10 carbon atoms such as ethynyl group, 1-propynyl group, 1-butynyl group, and 1-octynyl group. The substituent that R ³ may have is the same as those exemplified as the substituent that R ² can introduce. The number of carbon atoms of ^{R 3} is 1 to 10 including the carbon number of the substituent.

  A in the general formula (i) is preferably an oxygen atom or —NH— because synthesis is easy.

  N in the general formula (i) represents an integer of 1 to 5, and is preferably 1 in terms of printing durability.

  Although the preferable specific example of the repeating unit represented by general formula (i) below is shown, this invention is not limited to these.

  One type of repeating unit represented by the general formula (i) may be contained in the binder polymer, or two or more types may be contained. The specific binder polymer (1) in the present invention may be a polymer consisting only of the repeating unit represented by the general formula (i), but is usually combined with other copolymerization components and used as a copolymer. The total content of the repeating unit represented by the general formula (i) in the copolymer is appropriately determined depending on its structure, the design of the photosensitive layer composition, etc., but preferably 1 to 99 with respect to the total molar amount of the polymer component. It is contained in the range of mol%, more preferably 5 to 40 mol%, still more preferably 5 to 20 mol%.

  As a copolymerization component in the case of using as a copolymer, a conventionally well-known thing can be used without a restriction | limiting if it is a monomer which can be radically polymerized. Specific examples include monomers described in “Polymer Data Handbook—Basic Edition” (Edition of Polymer Society, Bafukan, 1986). One type of such copolymerization component may be used, or two or more types may be used in combination.

The molecular weight of the specific binder polymer (1) in the present invention is appropriately determined from the viewpoint of image formability and printing durability. The molecular weight is preferably in the range of 2,000 to 1,000,000, more preferably 5,000 to 500,000, and still more preferably 10,000 to 200,000.
The acid value (meq / g) of the specific binder polymer (1) is preferably in the range of 2.00 to 3.60.

The specific binder polymer (1) in the present invention may be used alone or in combination with one or more other binder polymers.
The binder polymer used in combination is used in the range of 1 to 60% by mass, preferably 1 to 40% by mass, and more preferably 1 to 20% by mass with respect to the total mass of the binder polymer component. As the binder polymer that can be used in combination, conventionally known ones can be used without limitation, and specifically, an acrylic main chain binder, a urethane binder, etc. often used in the industry, and a binder polymer having a radical polymerizable group described later. Is preferably used.

-Other binder polymers that can be used together-
The other binder polymer that can be used in combination with the specific binder polymer (1) is preferably a binder polymer having a radical polymerizable group.
The radical polymerizable group is not particularly limited as long as it can be polymerized by a radical, but α-substituted methylacrylic group [—OC (═O) —C (—CH ₂ Z) ═CH ₂ , Z = A hydrocarbon group starting from a hetero atom], an acryl group, a methacryl group, an allyl group, and a styryl group. Among these, an acryl group and a methacryl group are preferable.
The content of the radical polymerizable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 1 g per binder polymer from the viewpoint of sensitivity and storage stability. It is 10.0 mmol, More preferably, it is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol.

  Further, the other binder polymer that can be used in combination is preferably one having an alkali-soluble group. The content of alkali-soluble groups in the binder polymer (acid value by neutralization titration) is preferably from 0.1 to 3.0 mmol, more preferably from 1 to 3.0 g of binder polymer, from the viewpoints of precipitation of developing residue and printing durability. Is 0.2 to 2.0 mmol, most preferably 0.45 to 1.0 mmol.

  The weight average molecular weight of such a binder polymer is preferably from 2,000 to 1,000,000, more preferably from 10,000 to 300, from the viewpoints of film properties (press life) and solubility in a coating solvent. In the range of 20,000 to 200,000.

Further, the glass transition point (Tg) of such a binder polymer is preferably 70 to 300 ° C., more preferably 80 to 250 ° C., and most preferably 90 to 90 ° C. from the viewpoints of storage stability, printing durability, and sensitivity. It is in the range of 200 ° C.
As a means for increasing the glass transition point of the binder polymer, the molecule preferably contains an amide group or an imide group, and particularly preferably contains a methacrylamide or a methacrylamide derivative.

In the present invention, further, Japanese Patent Publication No. 7-12004, Japanese Patent Publication No. 7-120041, Japanese Patent Publication No. 7-120042, Japanese Patent Publication No. 8-12424, Japanese Patent Publication No. 63-287944, Japanese Patent Publication No. 63-287947, Urethane-based binder polymers containing acid groups described in JP-A-1-2717741, Japanese Patent Application No. 11-352691 and the like can also be used. Since the binder polymer is very excellent in strength, it is advantageous in terms of printing durability and suitability for low exposure.
A binder having an amide group described in JP-A No. 11-171907 is suitable because it has excellent developability and film strength.

  In addition, polyvinyl pyrrolidone, polyethylene oxide, and the like are useful as the water-soluble linear organic polymer. In order to increase the strength of the cured film, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, and the like are also useful.

In a preferred embodiment, a binder polymer that does not require water and is soluble in alkali is used. By doing so, an organic solvent that is not environmentally preferable is not used as the developer, or the amount used can be limited to a very small amount. In such a method of use, the acid value of the binder polymer (the acid content per gram of polymer expressed as a chemical equivalent number) and the molecular weight are appropriately selected from the viewpoint of image strength and developability. The preferred acid value is 0.4 to 3.0 meq / g, and the preferred molecular weight is in the range of 3000 to 500,000 in terms of mass average molecular weight, more preferably the acid value is 0.6 to 2.0 and the molecular weight is It is in the range of 10,000 to 300,000.
In addition, these binder polymers can be used together with the specific binder polymer (2) and the specific binder polymer (3) described later as necessary.

-Specific binder polymer (2)-
In addition, as the binder polymer in the present invention, a binder polymer having a phenyl group substituted with a vinyl group in the side chain (hereinafter, appropriately referred to as a specific binder polymer (2)) can also be suitably used.
The binder polymer having a phenyl group substituted with a vinyl group in the side chain is one in which a phenyl group substituted with a vinyl group is bonded to the main chain directly or via a linking group. The linking group is not particularly limited, and includes any group, atom, or a complex group thereof. In addition to the vinyl group, the phenyl group may be substituted with a substitutable group or atom. Specific examples of the substitutable group or atom include a halogen atom, a carboxy group, and a sulfo group. Group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkoxy group, aryloxy group and the like. Furthermore, the vinyl group may be substituted with a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, or the like.

  The specific binder polymer (2) is preferably a binder polymer having a group represented by the following general formula (2) in the side chain.

In General Formula (2), Z ¹ represents a linking group, and R ¹ , R ² , and R ³ each independently represent a hydrogen atom, a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, or an amide group. Represents an amino group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, and the like, and these groups are substituted with an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, a hydroxy group, and the like. It may be. R ⁴ represents a substitutable group or atom. n represents 0 or 1, m ¹ represents an integer of 0 to 4, and k ¹ represents an integer of ¹ to 4.

The general formula (2) will be described in more detail.
R ⁴ is preferably a hydrogen atom.
Examples of the linking group represented by Z ¹ include an oxygen atom, a sulfur atom, an alkylene group, an alkenylene group, an arylene group, —N (R ^a ) —, —C (O) —O—, —C (R ^b ) = N—, —C (O) —, a sulfonyl group, a heterocyclic group, and a group represented by the following structural formula, or a group in which two or more are combined. Here, R ^a and R ^b each represent a hydrogen atom, an alkyl group, an aryl group, or the like. Furthermore, the above-described linking group may have a substituent such as an alkyl group, an aryl group, or a halogen atom.

  Examples of the heterocyclic group include pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring, thiadiazole ring, thiatriazole ring, indole ring. , Indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, quinoline ring, quinoxaline ring, etc. A nitrogen-containing heterocyclic ring, a furan ring, a thiophene ring and the like, and a substituent may be bonded to these heterocyclic rings.

Specific examples of the binder polymer having the group represented by the general formula (2) in the side chain include those shown below, but are not limited thereto.
In addition, in a structural formula, a number represents the mass% of each repeating unit in 100 mass% of all compositions of a copolymer.

  The weight average molecular weight of the specific binder polymer (2) is preferably 5000 to 1,000,000, more preferably 10,000 to 500,000, and 20,000 to 300,000. Is more preferable.

-Specific binder polymer (3)-
Moreover, the organic polymer which has an allyl group can also be used suitably as a binder polymer in this invention.
In particular, a binder polymer containing 0.7 meq / g to 8.0 meq / g of allyl group (that is, 7 × 10 ⁻⁴ mol to 8.0 × 10 ⁻³ mol of allyl group per gram) is preferable. Hereinafter, this binder polymer will be referred to as a specific binder polymer (3).

The specific binder polymer (3) is preferably a polymer or copolymer of allyl acrylate and / or allyl methacrylate.
More specifically, homopolymers such as polyallyl methacrylate, the above allyl acrylate and / or allyl methacrylate, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate , Butyl acrylate, butyl methacrylate, their alkyl esters, vinyl acetate, styrene, maleic anhydride, copolymers with other monomers such as acrylonitrile.

Another preferred example of the specific binder polymer (3) includes a polyurethane having an allyl group which may be either a pendant allyl group or a terminal allyl group (hereinafter referred to as an allyl group-containing polyurethane).
Polyurethanes having allyl groups can be prepared by reacting diisocyanates with diols having excess allyl groups to form polyurethanes.
Also, by reacting diisocyanate with a diol having a carboxyl group such as dimethylolpropionic acid, a polyurethane having a carboxyl group is prepared, and this carboxyl group is esterified with, for example, allyl alcohol to form an allyl ester group. A polyurethane having an allyl group can be obtained by converting to.

Examples of the diol having an allyl group include 3-allyloxy-1,2-propanediol and trimethylolpropane allyl ether. Examples of the diol having an allyl ester group include allyl 4,4-bis (hydroxyethyloxyphenyl) -pentanoate and 2,2-bis (hydroxymethyl) propanoate. Preferred diols are _{3-allyloxy-1,2-propanediol:} a _{(HO) CH 2 -CH (OH} ) -CH 2 -O-CH 2 -CH = CH 2.

These diols having an allyl group can be used alone or in combination, or further in combination with a diol containing no allyl group. However, these diols are used under conditions such that allyl groups are present in the range of 0.7 meq / g to 8.0 meq / g in the obtained polymer.
Examples of diols containing no allyl group used in the present invention include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, neopentyl glycol, 1,4-butanediol, and 1,6-hexane. Diols are mentioned.

The polyurethane having an allyl group may contain an acid group, that is, a group having _a pKa of 7 or less (for example, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, or a carboxylic acid group). Such polyurethanes are obtained by reacting an excess of a mixture of a diol having an allyl group and a diol containing one or more acid groups with a diisocyanate as described above. Useful diols containing one or more acid groups include, for example, dialkanol alkyl sulfonic acids, dialkanol alkyl phosphoric acids, and dialkanol alkyl phosphonic acids.

The polyurethane having an allyl group and an acid group is preferably a polyurethane having a carboxyl group and an allyl group. A polyurethane having a carboxyl group and an allyl group is obtained by reacting a diisocyanate with an excess of a mixture of an allyl group-containing diol and a carboxyl group-containing diol to form a polyurethane.
The mixing ratio in the mixture of diols is determined under conditions such that allyl groups are present in the range of 0.7 meq / g to 8.0 meq / g in the resulting polymer.

  Examples of useful diols having a carboxyl group include 2,2-bis (hydroxymethyl) propionic acid, (2,2-dimethylolpropanoic acid), 2,2-bis (2-hydroxyethyl) propanoic acid, 2,2-bis (3-hydroxypropyl) propanoic acid, bis (hydroxymethyl) acetic acid, bis (4-hydroxyphenyl) acetic acid, 2,2-bis (hydroxymethyl) butyric acid, 2,2-bis (hydroxymethyl) Dialkanol alkanoic acid such as pentanoic acid and tartaric acid, dihydroxybenzoic acid such as 3,5-dihydroxybenzoic acid, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenyltetracarboxylic dianhydride or 2,3,6,7-naphthalenetetracarboxylic acid Acid dianhydrides such as anhydrides, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,2- or 1,3-propanediol, polypropylene glycol, 1,2- or 1,4-butanediol, neo Examples thereof include dihydroxydicarboxylic acid obtained by reacting a diol with an acid dianhydride such as a reaction product of a diol such as pentyl glycol and 1,6-hexanediol.

In addition, aromatic and / or aliphatic diisocyanates can be used as the isocyanate used when synthesizing the polyurethane.
Examples of the aromatic diisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, tetramethylxylene diisocyanate, 4 , 4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, and 3,3′-dimethylbiphenyl-4,4′-diisocyanate.
Examples of the aliphatic diisocyanate include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4-methylene-bis (cyclohexyl isocyanate), methylcyclohexane-2,4- and 2 , 6-diisocyanate, and 1,4-bis (isocyanatomethyl) cyclohexane.
In the present invention, aromatic diisocyanate is preferably used.

  The specific binder polymer (3) as described above is 5,000 to 1,000,000, preferably 100,000 or less, more preferably 75,000 or less, as measured by gel permeation chromatography. More preferably, it has a weight average molecular weight of 50,000 or less.

The specific binder polymer (3) molecule may be a linear molecule or a branched molecule, and preferably has a polydispersity of 1 to 5.
The specific binder polymer (3) preferably has an acid value of 0 to 70 mgKOH / g, more preferably has an acid value of 0 to 50 mgKOH / g, and has an acid value of 0 to 30 mgKOH / g. Is more preferable.

In the present invention, the total amount of the binder polymer in the photosensitive layer can be appropriately determined, but is usually 10 to 90% by mass, preferably 20 to 80% by mass, based on the total mass of nonvolatile components in the photosensitive layer. %, More preferably in the range of 30 to 70% by mass.
Moreover, it is preferable to make the polymeric compound and binder polymer mentioned later into the range of 1 / 9-7 / 3 by mass ratio.

(Other ingredients)
In addition to the above basic components, the photosensitive layer according to the present invention may further contain other components suitable for its use and production method. Hereinafter, preferred additives will be exemplified.

-Colorant-
A dye or a pigment may be added to the photosensitive layer according to the present invention for the purpose of coloring. As a result, it is possible to improve the so-called plate inspection properties such as the visibility of the image after plate making as a printing plate and the suitability of an image density measuring machine. Specific examples of the colorant include pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes. Among them, a cationic dye is preferable.
Further, as the colorant, a dye having an absorption maximum having a polymerization inhibiting effect in the range of 500 nm to 700 nm may be used in addition to the plate inspection properties as described above. As this dye, those described in paragraph numbers [0013] to [0017] of JP-A-2005-107389 are used.
The addition amount of the dye and the pigment as the colorant is preferably about 0.5% by mass to about 5% by mass with respect to the nonvolatile component in the photosensitive layer.

-Polymerization inhibitor-
In the photosensitive layer according to the present invention and the coating solution for forming a photosensitive layer used for forming the photosensitive layer, a small amount of a thermal polymerization inhibitor may be added to prevent unnecessary thermal polymerization of the polymerizable compound. desirable. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4′-thiobis (3-methyl-6-t- Butylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the mass of the nonvolatile component in the photosensitive layer (or photosensitive layer forming coating solution).
If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide or the like may be added to prevent polymerization inhibition by oxygen and may be unevenly distributed on the surface of the layer in the course of drying after coating. The addition amount of the higher fatty acid derivative is preferably about 0.5% by mass to about 10% by mass with respect to the nonvolatile component in the photosensitive layer (or the photosensitive layer forming coating solution).

-A compound having a weight average molecular weight of 3,000 or less and having at least one carboxylic acid group-
The photosensitive layer according to the present invention may contain a compound having a weight average molecular weight of 3,000 or less and having at least one carboxylic acid group (hereinafter, appropriately referred to as a specific carboxylic acid compound). This specific carboxylic acid compound is, for example, an aliphatic carboxylic acid that may have a substituent, an aromatic carboxylic acid that may have a substituent, and a heterocyclic ring that may have a substituent. It can be selected from compounds such as directly linked carboxylic acids. Among these, phthalic acid derivatives, trimellitic acid derivatives, pyromellitic acid derivatives, succinic acid derivatives, benzoic acid derivatives, glycine derivatives, and the like are preferable.

  In the present invention, the specific carboxylic acid compound has a weight average molecular weight of 3000 or less, more preferably in the range of 60 to 2000, and still more preferably in the range of 100 to 1500. When the weight average molecular weight exceeds 3000, the specific carboxylic acid compound may be adsorbed on the support, which is not preferable.

  Specific examples (compounds No. 1 to No. 20) of the specific carboxylic acid compound suitably used in the present invention are listed below, but the present invention is not limited to these.

0.5 mass%-30 mass% are preferable with respect to the total solid which comprises a photosensitive layer, and, as for content of a specific carboxylic acid compound, 2 mass%-20 mass% are more preferable.
In addition, a specific carboxylic acid compound may be used individually by 1 type, and may use 2 or more types together.

-Other additives-
Furthermore, the photosensitive layer according to the present invention may be added with known additions such as inorganic fillers for improving the physical properties of the cured film, other plasticizers, and oil-sensitizing agents that can improve the ink deposition on the surface of the photosensitive layer. An agent may be added.
Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin and the like.
Generally, it can be added in a range of 10% by mass or less with respect to the total mass of these plasticizer, binder polymer and polymerizable compound.

  In addition, in the photosensitive layer according to the present invention, in order to enhance the effect of heating / exposure after development for the purpose of improving the film strength (printing durability) described later, a UV initiator, a thermal crosslinking agent, etc. are added. Can also be done.

The polymerizable negative photosensitive layer in the present invention is prepared by preparing a coating solution (coating solution for forming a photosensitive layer) obtained by dissolving the above-mentioned various components in a suitable solvent on a support, and using this as a support or an undercoat layer described later. It is formed by applying on top.
Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, lactic acid There are ethyl and the like.
These solvents can be used alone or in combination. The concentration of the solid content in the photosensitive layer forming coating solution is suitably 2 to 50% by mass.

In the present invention, the coating amount of the photosensitive layer mainly affects the sensitivity of the photosensitive layer, the developability, the strength and the printing durability of the exposed film, and is preferably selected appropriately according to the application. When the coating amount is too small, the printing durability is not sufficient. On the other hand, if the amount is too large, the sensitivity is lowered, it takes time for exposure, and a longer time is required for development processing, which is not preferable.
As a lithographic printing plate precursor that can cope with scanning exposure, the coating amount is suitably in the range of about 0.1 g / m ² to about 10 g / m ² in terms of the mass after drying. More preferably from 0.5 to 5 g / ^{m 2.}

[Protective layer]
The lithographic printing plate precursor according to the invention may have a protective layer on the photosensitive recording layer. Hereinafter, the protective layer will be described in detail.
It is desirable that the protective layer does not substantially inhibit the transmission of light used for exposure, has excellent adhesion to the photosensitive recording layer, and can be easily removed in a development process after exposure. Various devices relating to such a protective layer have been conventionally used, and are described in detail, for example, in US Pat. No. 3,458,311 and JP-A-55-49729. Such a protective layer can also be applied to the lithographic printing plate precursor according to the invention.

  Further, as described above, the photosensitive recording layer in the lithographic printing plate precursor according to the invention is preferably a polymerizable negative photosensitive layer containing a sensitizing dye, a polymerization initiator, a polymerizable compound, and a binder polymer. It is an aspect. On the polymerizable negative photosensitive layer, it is preferable to have a protective layer having an oxygen blocking ability that blocks oxygen in the atmosphere during exposure and exhibits a polymerization inhibiting action. On the other hand, from the viewpoint of stability during storage or suitability for safelight, it is also desirable to have an oxygen permeability that exhibits an effect of preventing dark polymerization, and a protective layer having an oxygen barrier property that has both functions. Is desirable.

(Water-soluble polymer compound)
As a material used as a main component for the protective layer, it is preferable to use a water-soluble polymer compound having relatively excellent crystallinity. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic And water-soluble polymers such as polyacrylic acid. Other useful water-soluble polymer compounds include polyvinyl pyrrolidone, gelatin and gum arabic.
These may be used alone or in combination.

Of these, the use of polyvinyl alcohol as the main component gives the best results for basic properties such as oxygen barrier properties and development removability.
Polyvinyl alcohol that can be used for the protective layer has the necessary oxygen barrier properties and water solubility, so long as it contains an unsubstituted vinyl alcohol unit, it may be partially substituted with ester, ether, and acetal. Good. Similarly, it may be a copolymer partially having other repeating units.

  Examples of the copolymer include 88-100% hydrolyzed polyvinyl acetate chloroacetate or propionate, polyvinyl formal, polyvinyl acetal, and copolymers thereof.

  Examples of the polyvinyl alcohol suitably used include those having a saponification degree of 71 to 100% and a molecular weight of 200 to 2400. From the viewpoint of good oxygen barrier properties, excellent film forming properties, and a low adhesion surface, it is more preferable to use polyvinyl alcohol having a saponification degree of 91 mol% or more.

  A commercial item can also be used as polyvinyl alcohol. Specific examples of commercially available polyvinyl alcohol include PVA-102, PVA-103, PVA-104, PVA-105, PVA-110, PVA-117, PVA-117H, and PVA-120 manufactured by Kuraray Co., Ltd. , PVA-124, PVA-124H, PVA-135H, PVA-HC, PVA-617, PVA-624, PVA-706, PVA-613, PVA-CS, PVA-CST, PVA-203, PVA-204, PVA -205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA-420, L-8, Nippon Synthetic Chemical Gohsenol NL-05, NM-11, NM-14, AL-0 manufactured by Kogyo Co., Ltd. , P-610, C-500, A-300, AH-17, JF-04, JF-05, JF-10, JF-17, JF-17L, JM- 05, JM-10, JM-17, JM-17L, JT-05, JT-13, JT-15 and the like.

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

  In consideration of the sensitivity of the lithographic printing plate precursor and the suppression of adhesion between the lithographic printing plate plates when the lithographic printing plate precursors are laminated, the water-soluble polymer compound is 45 to 45% of the total solid content in the protective layer. It is preferable to contain in the range of 95 mass%, and it is more preferable to contain in the range of 50-90 mass%.

  Further, at least one water-soluble polymer compound may be used in the protective layer, and a plurality of water-soluble polymer compounds may be used in combination. Even when a plurality of water-soluble polymer compounds are used in combination, the total amount (% by mass) is preferably within the above range.

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

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

-Filler-
In addition to the water-soluble polymer compound, the protective layer in the present invention preferably contains a filler. By containing a filler, it is possible to improve the scratch resistance of the surface of the photosensitive recording layer (polymerizable negative photosensitive layer), and further, it occurs when a lithographic printing plate precursor is laminated without interposing a slip sheet. Adhesion between adjacent lithographic printing plate precursors is suppressed, and the detachability between the lithographic printing plate precursors can be improved. This also has the advantage of improved handling.
As such a filler, any of an organic filler, an inorganic filler, an inorganic-organic composite filler, and the like may be used, and two or more of these may be mixed and used. Preferably, the inorganic filler and the organic filler are used in combination.

  The shape of the filler is appropriately selected depending on the purpose, but for example, fibrous, needle-like, plate-like, spherical, granular (herein, “granular” refers to “indefinitely shaped particles”, hereinafter, In the present specification, they are used in the same meaning.), Tetrapot shape, balloon shape and the like. Of these, preferred are plate-like, spherical and granular.

  Examples of the organic filler include synthetic resin particles and natural polymer particles. The organic filler is preferably resin particles such as acrylic resin, polyethylene, polypropylene, polyethylene oxide, polypropylene oxide, polyethyleneimine, polystyrene, polyurethane, polyurea, polyester, polyamide, polyimide, carboxymethylcellulose, gelatin, starch, chitin, chitosan, etc. More preferably, resin particles such as acrylic resin, polyethylene, polypropylene, and polystyrene are used.

A commercial item can also be used as an organic filler.
Specific examples of commercially available fillers suitable for the organic filler added to the protective layer include Chemipearl W100, W200, W300, W308, W310, W400, W401, W4005, W410, W500, WF640, and W700 manufactured by Mitsui Chemicals. W800, W900, W950, WP100, manufactured by Soken Chemical Co., Ltd., MX-150, MX-180, MX-300, MX-500, MX-1000, MX-1500H, MX-2000, MR-2HG, MR-7HG, MR-10HG, MR-3GSN, MR-5GSN, MR-2G, MR-7G, MR-10G, MR-20G, MR-5C, MR-7GC, SX-130H, SX-350H, SX-500H, SGP- 50C, SGP-70C, MBX-5, MBX-8, MBX made by Sekisui Plastics 12, MBX-15, MBX-20, MB20X-5, MB30X-5, MB30X-8, MB30X-20, SBX-6, SBX-8, SBX-12, SBX-17, and the like.

  The particle size distribution of the filler may be monodispersed or polydispersed, but is preferably monodispersed. The filler preferably has an average particle size of 1 to 20 μm, more preferably an average particle size of 2 to 15 μm, and still more preferably an average particle size of 3 to 10 μm. By setting it within these ranges, the effect of the present invention is more effectively expressed.

  The content of the organic filler is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, and still more preferably 2 to 10% by mass with respect to the total solid content of the protective layer.

Inorganic fillers include metals and metal compounds (eg, oxides, composite oxides, hydroxides, carbonates, sulfates, silicates, phosphates, nitrides, carbides, sulfides, and at least two of these) More specifically, mica, glass, zinc oxide, alumina, zircon oxide, tin oxide, potassium titanate, strontium titanate, aluminum borate, magnesium oxide, magnesium borate, aluminum hydroxide , Magnesium hydroxide, calcium hydroxide, titanium hydroxide, basic magnesium sulfate, calcium carbonate, magnesium carbonate, calcium sulfate, magnesium sulfate, calcium silicate, magnesium silicate, calcium phosphate, silicon nitride, titanium nitride, aluminum nitride, carbonized Silicon, titanium carbide, zinc sulfide and at least two of these Composite compound of the above and the like.
Preferred examples of the inorganic filler include mica, glass, alumina, potassium titanate, strontium titanate, aluminum borate, magnesium oxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium phosphate, and calcium sulfate.

Of these, inorganic fillers particularly suitable for the protective layer include inorganic layered compounds represented by mica.
By using an inorganic layered compound in the protective layer, the oxygen barrier property is further increased, and the film strength of the protective layer is further improved and scratch resistance is improved, and the matte property can be imparted to the protective layer. it can. As a result, the protective layer can suppress deterioration due to deformation or the like and generation of scratches in addition to the barrier property of oxygen or the like. Furthermore, when a lithographic printing plate precursor is laminated by imparting a matte property to the protective layer, the adhesion between the protective layer surface of the lithographic printing plate precursor and the back surface of the adjacent lithographic printing plate precursor is suppressed. Is possible.

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

Specific examples of the mica include muscovite, soda mica, phlogopite, biotite, and sericite. In addition, examples of the synthetic mica include non-swelling mica such as fluorine phlogopite mica KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 (Si ₄ O ₁₀ ) F ₂ , and Na tetrasilic mica. NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li Teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , Montmorillonite Na or Li Hectorite (Na, Li) _1/8 Examples thereof include swellable mica such as Mg _2/5 Li _1/8 (Si ₄ O ₁₀ ) F ₂ . In addition, synthetic smectites are also useful.

Of the mica, fluorine-based swellable mica is particularly useful. That is, this swellable synthetic mica has a laminated structure composed of unit crystal lattice layers having a thickness of about 1 to 1.5 nm, and the substitution of metal atoms in the lattice is significantly larger than other viscosity minerals. As a result, the lattice layer is deficient in positive charge, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Swellable synthetic mica has a strong tendency and is useful in the present invention. In particular, swellable synthetic mica is preferably used.

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

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

When an inorganic layered compound is used as the filler, the amount of the inorganic layered compound contained in the protective layer is the sensitivity by suppressing adhesion between lithographic printing plate precursors when they are laminated, suppressing scratches, and blocking during laser exposure. From the viewpoint of reduction, low oxygen permeability, etc., it is preferably in the range of 5 to 50% by mass, particularly preferably in the range of 10 to 40% by mass with respect to the total solid content of the protective layer. Even when a plurality of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass.
Similarly, the amount contained in the protective layer of the inorganic filler other than the inorganic layered compound is also preferably in the range of 5 to 50% by mass, and in the range of 10 to 40% by mass with respect to the total solid content of the protective layer. Particularly preferred.

  It is also preferable to use a mixture of an organic filler and an inorganic filler in the protective layer, and the mixing ratio is preferably a mass ratio of 1: 1 to 1: 5. In this case, the content of the filler in the protective layer is preferably in the range of 5 to 50% by mass, more preferably in the range of 10 to 40% by mass with respect to the total solid content of the protective layer. Is more preferable.

An inorganic-organic composite filler can also be used for the protective layer. Examples of inorganic-organic composite fillers include composites of organic fillers and inorganic fillers. Examples of inorganic fillers used for composites include metal powders, metal compounds (for example, oxides, nitrides, sulfides, Particles of carbides and composites thereof), preferably oxides and sulfides, more preferably glass, SiO ₂ , ZnO, Fe ₂ O ₃ , ZrO ₂ , SnO ₂ , ZnS, CuS, etc. Particles.
As content to the protective layer of an inorganic-organic composite filler, it is preferable that it is the range of 5-50 mass% with respect to the total solid content of a protective layer, and the range of 10-40 mass% is more preferable.

The inorganic-organic composite filler that can be used in the present invention preferably contains a silica component, and particularly preferably silica-coated fine particles in which a part of the surface of the filler is coated with a silica layer.
The presence of silica on at least a part of the filler surface achieves improved affinity between the filler and the binder (polyvinyl alcohol, etc.), and suppresses the filler from falling off even when external stress is applied to the protective layer. Can maintain excellent scratch resistance and adhesion resistance. The “silica coating” in the present invention includes a state in which silica is present on at least a part of the surface of the filler.

As the organic resin constituting the inorganic-organic composite filler that becomes the core of the silica-coated fine particles, any organic resin having physical properties required for the filler as described above can be used without limitation. For example, polyacrylic acid resin, polyurethane resin, polystyrene resin, polyester resin, epoxy resin, phenol resin, melamine resin, silicone resin and the like can be mentioned.
Of these, polyacrylic acid resins, polyurethane resins, melamine resins, and the like are preferable from the viewpoint of affinity with polyvinyl alcohol, which is a preferred binder for the protective layer.

In addition, as a material for forming a silica layer covering the filler surface, compounds having an alkoxysilyl group such as a condensate of an alkoxysiloxane compound, particularly a siloxane material used in a sol-gel method, silica sol, colloidal silica Preferred are silica fine particles such as silica nanoparticles.
The composition of the silica-coated fine particles is that in which the silica fine particles are adhered as a solid component on the filler surface, and a siloxane compound layer is formed on the filler surface by condensation reaction of the alkoxysiloxane compound. Also good.

Silica does not necessarily have to cover the entire surface of the filler, and the above-mentioned effects can be obtained if the surface is coated in an amount of 0.5% by mass or more with respect to at least the filler.
The surface coating state of silica can be confirmed by morphological observation with a scanning electron microscope (TEM) or the like, and the silica coating amount is detected by detecting Si atoms by elemental analysis such as fluorescent X-ray analysis. This can be confirmed by calculating the amount of silica present.

  There is no particular limitation on the method for producing the silica-coated fine particles, and the silica surface coating layer may be formed simultaneously with the filler formation by coexisting the silica fine particles or the silica precursor compound with the monomer component as the raw material of the resin fine particles. Alternatively, after the filler is formed, the silica fine particles may be physically attached to the surface and then fixed.

  As an example of the method for producing silica-coated fine particles, first, a suspension stabilizer appropriately selected from water-soluble polymers such as polyvinyl alcohol, methylcellulose, and polyacrylic acid, and inorganic suspensions such as calcium phosphate and calcium carbonate. In water containing silica and a raw material resin (more specifically, a raw material resin such as a monomer capable of suspension polymerization, a prepolymer capable of suspension crosslinking, or a resin liquid constituting the organic resin described above) Are added, stirred, and mixed to prepare a suspension in which silica and a hydrophobic raw resin are dispersed. At that time, an emulsion (suspension) having a target particle size can be formed by adjusting the type of suspension stabilizer, its concentration, the number of stirring revolutions, and the like. Next, the suspension is heated to start the reaction, and resin particles are produced by suspension polymerization or suspension crosslinking of the resin raw material. At this time, the coexisting silica is fixed to the resin particles that are cured by polymerization or cross-linking reaction, particularly near the surface of the resin particles due to the physical properties thereof. Thereafter, this is subjected to solid-liquid separation, and the suspension stabilizer attached to the particles is removed by washing, followed by drying. Thereby, substantially spherical organic resin particles having a desired particle size on which silica is immobilized are obtained.

  As described above, a resin having a desired size can be obtained by controlling the conditions during suspension polymerization or suspension crosslinking. However, the silica-adhered inorganic-organic composite filler can be obtained without strict control. Then, silica-coated fine particles having a desired size can be obtained by a mesh filtration method.

  When the total amount of the raw material resin and silica is 100 parts by mass, the addition amount of the raw material in the mixture when the silica-coated fine particles are produced by the above method is first suspended stably in 200 to 800 parts by weight of water as a dispersion medium. 0.1 to 20 parts by mass of the agent is added and sufficiently dissolved or dispersed, and the mixture of 100 parts by mass of the raw material resin and silica is added to the liquid so that the dispersed particles have a predetermined particle size. After adjusting the particle size, the liquid temperature is raised to 30 to 90 ° C. and reacted for 1 to 8 hours.

  As for the method for producing silica-coated fine particles, the above-described method is an example, and for example, JP 2002-327036 A, JP 2002-173410 A, JP 2004-307837 A, JP 2006-38246 A, and the like. The method described in detail in can also be applied. Further, any silica-coated fine particles obtained by the method described herein can be suitably used in the present invention.

  The silica-coated fine particles that can be used in the present invention are also available as commercial products. As specific examples, silica / melamine composite fine particles include Nissan Chemical Industries Co., Ltd. Opt Bead 2000M, Opt Bead 3500M, Examples thereof include opt beads 6500M, opt beads 10500M, opt beads 3500S, and opt beads 6500S. As silica / acrylic composite fine particles, Negami Industrial Co., Ltd. Art Pearl G-200 transparent, Art Pearl G-400 transparent, Art Pearl G-800 transparent, Art Pearl GR-400 transparent, Art Pearl GR-600 transparent, Art Pearl GR-800 transparent, Art Pearl J-7P. As the silica / urethane composite fine particles, Negami Industrial Co., Ltd. Art Pearl C-400 Transparent, C-800 Transparent, P-800T, U-600T, U-800T, CF-600T, CF800T, Dainichi Seika Co., Ltd. Dynamic Examples thereof include beads CN5070D and dampula coat THU.

The hardness of the silica-coated fine particles is preferably 0.0005 to 0.20 GPa, more preferably 0.001 to 0.15 GPa, as measured with a device in which a Triboscope made by Hystron is connected to a Multimode AFM made by Vigo. The most preferred hardness is 0.003 to 0.010 Gpa. This hardness can be adjusted as appropriate depending on the material of the silica-coated fine particles, the coating amount of the silica layer, and the like.
Here, when the protective layer in the present invention has a multilayer structure and silica-coated fine particles are added to the upper protective layer, the hardness of the silica-coated fine particles may be the same as or smaller than the hardness of the lower protective layer. preferable.

The shape of the silica-coated fine particles according to the present invention is preferably a true spherical shape, but may be a flat plate shape or an elliptical shape.
The preferable average particle diameter of the silica-coated fine particles according to the present invention is 1 to 30 μmφ, more preferably 1.5 to 20 μmφ, and most preferably 2 to 15 μmφ. In this range, a sufficient spacer function and mat performance can be expressed, the immobilization on the surface of the protective layer is easy, and the holding function is excellent against contact stress from the outside.
In particular, the true specific gravity of the silica-coated fine particles is in the range of 0.90 to 1.30, the average particle diameter is preferably 2.0 to 15 μm, and the true specific gravity is 0.90 to 1.20. And is more preferably 3.0 to 12 μm.

The preferred amount of silica-coated fine particles added to the protective layer is 5 to 1000 mg / m ² , more preferably 10 to 500 mg / m ² , and most preferably 20 to 200 mg / m ² .
More specifically, the content of the silica-coated fine particles in the solid content of the protective layer is 1.0% by mass to from the viewpoints of surface mat effect expression, sensitivity, and separation of particles from the surface of the protective layer. 20 mass% is preferable and 2.0 mass%-10 mass% are more preferable.

  Components of the protective layer (selection of polyvinyl alcohol and inorganic layered compounds, use of additives), coating amount, etc. are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability The

In the present invention, the protective layer is not limited to a single layer, and a plurality of protective layers having different compositions can be provided in a multilayer structure. As a preferred embodiment of the protective layer having a multilayer structure, a protective layer containing an inorganic layered compound is provided as a lower protective layer in the vicinity of the recording layer, and a protective layer containing an inorganic layered compound and an organic filler is provided on the surface. As the upper protective layer, an embodiment in which these are sequentially laminated can be mentioned.
By providing a protective layer having such a laminated structure, the uppermost protective layer has the excellent oxygen barrier properties and compatibility with the lower protective layer while fully utilizing the advantages of scratch resistance and adhesion resistance due to the filler. Thus, it is possible to effectively prevent image defects due to both the generation of scratches and undesired oxygen permeation.

The protective layer in the present invention preferably has an oxygen permeability at 25 ° C.-1 atm of 0.5 ml / m ² · day to 100 ml / m ² · day, so as to achieve such oxygen permeability. Further, it is preferable to adjust the coating amount.

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

(Formation of protective layer)
The formation of the protective layer is not particularly limited, and is carried out by applying a protective layer-forming coating solution containing the above components on the photosensitive recording layer (polymerizable negative photosensitive layer). For example, the method described in U.S. Pat. No. 3,458,311 or JP-A-55-49729 can also be applied.

  Hereinafter, as an example of a method for applying the protective layer, a method for applying the protective layer containing an inorganic layered compound such as mica and a water-soluble polymer compound such as polyvinyl alcohol will be described in detail. A dispersion in which an inorganic layered compound such as mica is dispersed is prepared, and the dispersion is mixed with a water-soluble polymer compound such as polyvinyl alcohol (or an aqueous solution in which a water-soluble polymer compound is dissolved). A protective layer is formed by applying a coating solution for forming a protective layer to the photosensitive recording layer (polymerizable negative photosensitive layer).

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

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

The coating amount of the protective layer is 0.1 g / mass after drying from the viewpoint of maintaining the film strength and scratch resistance of the protective layer, maintaining the image quality, and maintaining appropriate oxygen permeability for imparting safelight suitability. m ^{2 to} 4.0 g / m ² is preferable, and 0.3 g / m ^{2 to} 3.0 g / m ² is more preferable.

Also, in the case of providing a protective layer having a multilayer structure, the coating method is not particularly limited, and either a method of simultaneous multilayer coating or a method of sequential coating and multilayering can be applied. The coating amount of the lower protective layer containing the inorganic stratiform compound and the upper protective layer containing the inorganic stratiform compound and the organic filler is the mass after drying, and the lower protective layer is 0.1 g / m ² to 1. preferably 5 g / ^{m 2,} more preferably ^{0.2g / m 2 ~1.0g / m 2} , the upper protective layer is 0.1g ^{/ m 2} ~4.0g ^/ m 2 preferably, 0.2 g / ^{m 2} -3.0 g / m < ² > is more preferable. The balance between the two is preferably 1: 1 to 1: 5.

[Support]
Examples of the support in the present invention include paper, a polyester film or an aluminum plate. Among them, a surface having good dimensional stability, relatively inexpensive, and having excellent hydrophilicity and strength by surface treatment as necessary. An aluminum plate that can be provided is more preferred. A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

  The aluminum plate as the most preferable support in the present invention is a metal plate mainly composed of dimensionally stable aluminum, and contains pure aluminum plate, aluminum as a main component, and a trace amount of foreign elements. An alloy plate or aluminum (alloy) is selected from a laminated or vapor-deposited plastic film or paper. In the following description, the above-mentioned support made of aluminum or an aluminum alloy is generically used as an aluminum support. Examples of the foreign element contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is 10% by mass or less. In the present invention, a pure aluminum plate is suitable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. Thus, the composition of the aluminum plate applied to the present invention is not specified, and it is a conventionally known material such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. Can be used as appropriate.

Moreover, the thickness of the aluminum support body used for this invention is about 0.1 mm-about 0.6 mm. This thickness can be changed as appropriate according to the size of the printing press, the size of the printing plate, and the desire of the user.
Such a support (aluminum support) is subjected to a surface treatment described later to be hydrophilized.

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

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

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

A widely known method can be applied as the hydrophilic treatment on the surface of the support. As a particularly preferable treatment, a hydrophilic treatment with silicate or polyvinylphosphonic acid is performed. A film | membrane is formed by 2-40 mg / m < ² > as Si or P element amount, More preferably, it is 4-30 mg / m < ² >. The coating amount can be measured by fluorescent X-ray analysis.

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

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

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

[Intermediate layer (undercoat layer)]
In the lithographic printing plate precursor according to the invention, an intermediate layer (undercoat layer) may be provided for the purpose of improving the adhesion and soiling between the photosensitive layer and the support. Specific examples of such an intermediate layer include JP-B-50-7481, JP-A-54-72104, JP-A-59-101651, JP-A-60-149491, JP-A-60-232998, JP-A-3-56177, JP-A-4-282737, JP-A-5-16558, JP-A-5-246171, JP-A-7-159983, JP-A-7-314937, JP-A-8-202025, Special Kaihei 8-320551, JP 9-34104, JP 9-236911, JP 9-269593, JP 10-69092, JP 10-115931, JP 10-161317, JP 10-260536, JP-A-10-282682, JP-A-11-84684, JP-A-10-69092, JP-A-10-115931, Kaihei 11-38635, JP-A-11-38629, JP-A-10-282645, JP-A-10-301262, JP-A-11-24277, JP-A-11-109641, JP-A-10-319600, JP-A-10-319600 11-84684, JP-A-11-327152, JP-A-2000-10292, JP-A-2000-235254, JP-A-2000-352854, JP-A-2001-209170, Japanese Patent Application No. 11-284091, etc. Can be mentioned.

<Plate making method>
Hereinafter, a method for making a lithographic printing plate precursor according to the present invention will be described.
The lithographic printing plate precursor according to the invention is a laminate in which a plurality of sheets are laminated by directly contacting the outermost surface on the recording layer side and the outermost surface on the backcoat layer side (laminate of the lithographic printing plate precursor according to the invention) Then, the laminate is set in a plate setter, the lithographic printing plate precursor is automatically conveyed one by one, exposed, and then subjected to development.
The lithographic printing plate precursor of the present invention suppresses the adhesion between the lithographic printing plate precursors and the generation of scratches on the protective layer even if they are laminated without interposing the interleaf between the plates. It can be applied to such a plate making method. In addition, since the laminated body (laminated body of the lithographic printing plate precursor of the present invention) in which the lithographic printing plate precursor is laminated without sandwiching the interleaving paper can be used for the plate making method, removal of the interleaving paper becomes unnecessary, Productivity in the plate making process is improved.

  In the case where the lithographic printing plate precursor of the present invention has a constitution in which a protective layer is provided on a polymerizable negative photosensitive layer having an infrared absorber as a sensitizing dye, a plurality of sheets are obtained by directly contacting the protective layer and the backcoat layer. After the laminated body is set in a plate setter and the lithographic printing plate precursor is automatically conveyed one by one, after being exposed at a wavelength of 750 nm to 1400 nm, substantially without undergoing a heat treatment, It is possible to make a plate by carrying out development processing under a condition where the conveyance speed is 1.25 m / min or more.

〔exposure〕
As the light source used for the exposure processing in the present invention, a known light source can be used without limitation. The wavelength of the light source is preferably in the range of 300 nm to 1200 nm. Specifically, various lasers can be used as the light source, and among them, a semiconductor laser that emits infrared light with a wavelength of 760 nm to 1200 nm can be used.

A laser is preferable as the light source. For example, the following laser light sources having a wavelength of 350 to 450 nm can be used.
As a gas laser, Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), He—Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and solid laser Nd: YAG combination of (YVO ₄₎ and SHG crystal × 2 times (355mm, 5mW~1W), Cr: LiS
A combination of AF and SHG crystals (430 nm, 10 mW) can be mentioned. As the semiconductor laser system, KNbO ₃ , ring resonator (430 nm, 30 mW), waveguide type wavelength conversion element and AlGaAs, InGaAs semiconductor combination (380 nm to 450 nm, 5 mW to 100 mW), waveguide type wavelength conversion element and AlGaInP, Combination of AlGaAs semiconductors (300 nm to 350 nm, 5 mW to 100 mW), AlGaInN (350 nm to 450 nm, 5 mW to 30 mW), other pulse lasers such as N ₂ laser (337 nm, pulse 0.1 to 10 mJ), XeF (351 nm, pulse 10 ~ 250 mJ).
In particular, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 400 to 410 nm, 5 to 30 mW) is preferable in terms of wavelength characteristics and cost.

In addition, as an available light source of 450 nm to 700 nm, Ar ⁺ laser − (488 n
m), YAG-SHG laser (532 nm), He—Ne laser (633 nm), He—Cd laser, and red semiconductor laser (650 to 690 nm). As an available light source of 700 nm to 1200 nm, a semiconductor laser (800˜ 850 nm) and Nd-YAG laser (1064 nm) can be suitably used.

  In addition, ultra high pressure, high pressure, medium pressure, low pressure mercury lamp, chemical lamp, carbon arc lamp, xenon lamp, metal halide lamp, ultraviolet laser lamp (ArF excimer laser, KrF excimer laser, etc.), various visible laser lamps, fluorescent light An electron beam, an X-ray, an ion beam, a far-infrared ray, or the like can be used as the radiation such as a lamp, a tungsten lamp, or sunlight.

  Among the above, as a light source of light used for image exposure, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser or a semiconductor laser is particularly preferable.

In particular, when a wavelength of 750 nm to 1400 nm is used as an exposure light source, it can be used without particular limitation as long as it emits light of the wavelength, but preferably an image is emitted by a solid laser or semiconductor laser emitting infrared rays of a wavelength of 750 nm to 1400 nm. It is preferable to be exposed.
The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec. The amount of energy per unit irradiated on the lithographic printing plate precursor is preferably 10 to 300 mJ / cm ² .

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

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

In the present invention, the lithographic printing plate precursor subjected to the exposure treatment as described above may be subjected to a heat treatment and a water washing treatment.
Further, depending on the type of the lithographic printing plate precursor, for example, when it has a polymerizable negative photosensitive layer, it may be subjected to development processing without performing special heat treatment and water washing treatment. By not performing this heat treatment, image non-uniformity due to the heat treatment can be suppressed. Further, by performing neither heat treatment nor water washing treatment, stable high-speed processing is possible in development processing.

〔developing〕
In the development processing in the present invention, a non-image portion of the photosensitive layer is removed using a developer.
In the present invention, as described above, in the case of a lithographic printing plate precursor having a protective layer on a polymerizable negative photosensitive layer having an infrared absorber as a sensitizing dye, the processing speed in the development process, That is, the transport speed (line speed) of the lithographic printing plate precursor in the development process is preferably 1.25 m / min or more, more preferably 1.35 m / min or more. Moreover, there is no restriction | limiting in particular in the upper limit of a conveyance speed, However, From a viewpoint of stability of conveyance, it is preferable that it is 3 m / min or less.
Hereinafter, the developer used in the present invention will be described.

(Developer)
The developer used in the present invention is preferably an alkaline aqueous solution having a pH of 14 or less, and preferably contains an aromatic anionic surfactant.

(Aromatic anionic surfactant)
The aromatic anionic surfactant used in the developer in the present invention has a development accelerating effect and a dispersion stabilizing effect in the developer of the polymerizable negative photosensitive layer component and the protective layer component. preferable. Among these, the aromatic anionic surfactant used in the present invention is preferably a compound represented by the following general formula (A) or general formula (B).

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

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

  These aromatic anionic surfactants may be used alone or in appropriate combination of two or more. The amount of the aromatic anionic surfactant added is preferably such that the concentration of the aromatic anionic surfactant in the developer is in the range of 1.0 to 10% by mass, more preferably in the range of 2 to 10% by mass. It is effective to do. Here, if the content is 1.0% by mass or less, the developability and the solubility of the photosensitive layer components are lowered, and if the content is 10% by mass or more, the printing durability of the printing plate is reduced. .

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

(Chelating agent for divalent metals)
The developer according to the present invention preferably contains a chelating agent for a divalent metal, for example, for the purpose of suppressing the influence of calcium ions contained in hard water. Examples of chelating agents for divalent metals include Na ₂ P ₂ O ₇ , Na ₅ P ₃ O ₃ , Na ₃ P ₃ O ₉ , Na ₂ O ₄ P (NaO ₃ P) PO ₃ Na ₂ , Calgon (polymetalin). Polyphosphates such as ethylenediaminetetraacetic acid, its potassium salt, its sodium salt, its amine salt; diethylenetriaminepentaacetic acid, its potassium salt, sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt Hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its potassium salt, its sodium salt; 1,2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt; 1,3-diamino-2 -Propanol tetraacetic acid 2-phosphonobutanetricarboxylic acid-1,2,4, potassium salt, sodium salt thereof; 2-phosphonobutanone tricarboxylic acid-2, in addition to aminopolycarboxylic acids such as potassium salt, sodium salt, etc. 3,4, its potassium salt, its sodium salt; 1-phosphonoethanetricarboxylic acid-1,2,2, its potassium salt, its sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt, Examples thereof include organic phosphonic acids such as aminotri (methylenephosphonic acid), potassium salt, sodium salt, and the like. Among them, ethylenediaminetetraacetic acid, potassium salt, sodium salt, amine salt; ethylenediamine; Tetra (methylenephosphonic acid), its ammonium salt, its potash Salt; hexamethylenediamine tetra (methylene phosphonic acid), an ammonium salt, its potassium salt is preferred.
The optimum amount of such a chelating agent varies depending on the hardness of the hard water used and the amount used, but is generally 0.01 to 5% by mass, more preferably 0% in the developing solution at the time of use. It is made to contain in the range of 0.01-0.5 mass%.

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

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

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

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

In addition, the alkali silicate concentration in the developer includes the effect of inhibiting dissolution (etching) of the anodic oxide film on the support, the developability, the effect of inhibiting precipitation and crystal formation, and the gelation during neutralization during waste From the viewpoint of the prevention effect and the like, the SiO ₂ amount is preferably 0.01 to 1 mol / L, more preferably 0.05 to 0.8 mol / L with respect to the mass of the developer.

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

  The developer used in the present invention preferably has a pH in the range of 10 to 12.5 at 25 ° C, and more preferably in the range of pH 11 to 12.5. Since the developer in the present invention contains the surfactant, even if such a low pH developer is used, excellent developability is exhibited in the non-image area. Thus, by setting the pH of the developing solution to a relatively low value, damage to the image area during development is reduced and the handling property of the developing solution is excellent.

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

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

    Furthermore, in order to restore the processing capacity of the developer using an automatic developing machine, it is preferable to replenish by the method described in US Pat. No. 4,882,246. Developers described in JP-A-50-26601, 58-54341, JP-B-56-39464, 56-42860, and 57-7427 are also preferable.

  A more preferred development replenisher of the present invention contains an oxycarboxylic acid chelating agent having an ability to form a water-soluble chelate compound with aluminum ions, an alkali metal hydroxide, and a surfactant, and contains a silicate. A developing replenisher characterized by being an aqueous solution having a pH of 11 to 13.5. By using such a development replenisher, it has excellent developability and characteristics that do not impair the strength of the image area of the plate material, and is formed by elution of the aluminum support by the alkali of the developer. Precipitation of aluminum is effectively suppressed, and adhesion of stains mainly composed of aluminum hydroxide to the surface of the developing bath roller of the automatic processor and subsequent accumulation of aluminum hydroxide precipitates in the washing bath are reduced. It can be processed stably for a long time.

  The lithographic printing plate thus developed is washed with water or a surfactant as described in JP-A Nos. 54-8002, 55-1115045, 59-58431, and the like. And the like, and a post-treatment with a desensitizing solution containing gum arabic, starch derivatives and the like. These processes may be performed in various combinations.

Furthermore, the lithographic printing plate after development can be subjected to full post-heating or full exposure on the developed image for the purpose of improving image strength and printing durability.
Very strong conditions can be used for heating after development. Usually, the heating temperature is 200 to 500 ° C. If the heating temperature after development is low, sufficient image strengthening action cannot be obtained, and if it is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.

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

  Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto.

[Synthesis Example 1: Synthesis of polymer (P-1)]
150 g of bismuthiol (2,5-dimercapto-1,3-4-thiadiazole) was suspended in 600 ml of methanol, and 101 g of triethylamine was gradually added while cooling to obtain a uniform solution. While maintaining at room temperature, p-chloromethylstyrene (manufactured by Seimi Chemical Co., CMS-14) was added dropwise over 10 minutes, and stirring was further continued for 3 hours. The reaction product gradually precipitated. After stirring, the reaction product was transferred to an ice bath, the internal temperature was cooled to 10 ° C., and the product was separated by suction filtration. The compound (monomer) shown below was obtained with a yield of 75% by washing with methanol and drying for one day in a vacuum dryer.

  40 g of the monomer obtained above is placed in a 1-liter four-necked flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser, 70 g of methacrylic acid, 200 ml of ethanol and 50 ml of distilled water are added, and the water bath is stirred. Above, 110 g of triethylamine was added. Under nitrogen atmosphere, the internal temperature was heated to 70 ° C., and 1 g of azobisisobutyronitrile (AIBN) was added at this temperature to initiate polymerization. The mixture was heated and stirred for 6 hours, and then the polymerization system was cooled to room temperature. A part was taken out, diluted hydrochloric acid was added to adjust the pH to about 3, and this was opened in water to obtain a polymer having the structure shown below.

  100 g of 1,4-dioxane and 23 g of p-chloromethylstyrene were added to the remaining polymer solution from which a part of the polymer was taken out, and stirring was further continued at room temperature for 15 hours. Thereafter, 80 to 90 g of concentrated hydrochloric acid (35 to 37% aqueous solution) was added, and after confirming that the pH of the system was 4 or less, the whole was transferred into 3 liters of distilled water. The precipitated polymer was separated by filtration, washed repeatedly with distilled water, and then dried for one day in a vacuum dryer. Thereby, the target polymer (P-1) was obtained with a yield of 90%. It is a polymer having a weight average molecular weight of 90,000 (polystyrene conversion) by molecular weight measurement by gel permeation chromatography, and further supports the structure of the polymer (P-1) by analysis by proton NMR. Was confirmed. The polymer (P-1) is the compound described above as a specific example (P-1) of the binder polymer (specific binder polymer (2)) having a group represented by the general formula (2) in the side chain.

[Synthesis Example 2: Synthesis of Monomer (C-5)]
A thirocyanuric acid 89g was suspended in 1.5 liters of methanol, and a 30% aqueous solution in which 84 g of potassium hydroxide was dissolved was gradually added while cooling to obtain a uniform solution. To this, 230 g of p-chloromethylstyrene was gradually added dropwise at room temperature so that the internal temperature did not exceed 40 ° C. Shortly after the addition, the product precipitated, but the stirring was continued, and after stirring for 3 hours, the product was separated by suction filtration. After washing with methanol and drying all day and night in a vacuum dryer, a monomer (C-5) was obtained with a yield of 90%. The monomer (C-5) is the compound described above as a specific example (C-5) of the compound (specific monomer) represented by the general formula (3).

[Synthesis Example 3: Synthesis of Polymer (P-2)]
N, N-dimethylacetamide (352.1 g) was charged into a 1 liter four-necked flask equipped with a mantle heater, temperature controller, mechanical stirrer, condenser, isobaric dropping funnel and nitrogen inlet tube. Then 4,4′-methylene-bis (phenyl isocyanate) (150.4 g) (0.6 mol) was added slowly with stirring at room temperature. After 10 minutes, 2,2-dimethylolpropanoic acid (40.2 g) (0.3 mol) was added at ambient temperature. The temperature of the reaction mixture rose to 57 ° C. Then 3-allyloxy-1,2-propanediol (43.6 g) (0.33 mol) was added over 30 minutes. The reaction mixture was further stirred for 2 hours to obtain a transparent solution containing the polymer (P-2). Completion of the reaction was determined by the disappearance of the infrared absorption band of isocyanate at 2275 cm ⁻¹ . The obtained transparent solution had a kinematic viscosity (Gardner-Holt) of Z _{1 at} a nonvolatile content of 40%.

Next, the clear solution containing the polymer (P-2) was stirred with water (4.5 Kg) while stirring at 6000 rpm using a Silverstone Model # L4RT-A (Silverston Model # L4RT-A) multipurpose high shear laboratory mixer. Ice (1.5 Kg) was added to precipitate the polymer (P-2) in powder form. The mixture was agitated at 4000 rpm for about 10-15 minutes using a Series 2000, Model # 84, laboratory dispersator (Series 2000, Model # 84, Laboratory Dispersator). Furthermore, the polymer (P-2) was separated by filtration and dried at 60 ° C. in a drying oven. The polymer (P-2) had about 1.41 meq of allyl group per gram of the polymer. The acid value of the polymer (P-2) was 57 mg KOH per gram of the polymer. Furthermore, the weight average molecular weight of the polymer (P-2) is 100,000.
This polymer (P-2) corresponds to the specific binder polymer (3).

[ Reference Example 1]
(Production of support)
The surface treatment shown below was performed using a JIS A 1050 aluminum plate having a thickness of 0.30 mm and a width of 1030 mm.

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

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

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

(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (including 0.5% by mass aluminum ions and 0.007% by mass ammonium ions) at a temperature of 30 ° C. The AC power source was subjected to an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 2 msec until the current value reached a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the current peak value, and the amount of electricity was 250 C / cm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Thereafter, it was washed with water.

(D) The aluminum plate was etched by spraying at 35 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass, the aluminum plate was dissolved at 0.2 g / m ² , and electricity was obtained using the previous AC. The removal of the smut component mainly composed of aluminum hydroxide generated during chemical roughening and the edge portion of the generated pit were dissolved to smooth the edge portion. Thereafter, it was washed with water.

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

(F) Anodization was performed for 50 seconds at a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), a temperature of 33 ° C., and a current density of 5 (A / dm ² ). Thereafter, it was washed with water. At this time, the weight of the anodized film was 2.7 g / m ² .

  The surface roughness Ra, surface area ratio ΔS, and steepness a45 of the aluminum support thus obtained were Ra = 0.27 (measuring instrument: Surfcom manufactured by Tokyo Seimitsu Co., Ltd., stylus tip diameter 2 microns), respectively. Meter), ΔS = 75%, a45 = 44% (measuring instrument: SPA300 / SPI3800N manufactured by Seiko Instruments Inc.).

(Formation of back coat layer)
Next, the following coating solution for forming a back coat layer was prepared and applied to the aluminum support using a wire bar. Drying was performed at 100 ° C. for 70 seconds with a hot air drying apparatus to obtain a support on which a backcoat layer was formed. The total coating amount of this back coat layer (the coating amount after drying) was 0.46 g / m ² .

<Backcoat layer forming coating solution>
・ JER1009 (the following structure: Japan Epoxy Resin Co., Ltd.) 1.00 g
・ Fluorine surfactant 0.005g
(Megafuck F-780-F, Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 22.5g
・ 2.5 g of 1-methoxy-2-propanol

(Formation of undercoat layer)
Subsequently, the following undercoat layer-forming coating solution was applied with a wire bar to the surface of the aluminum support opposite to the surface on which the backcoat layer was formed, and dried at 90 ° C. for 30 seconds. The coating amount was 10 mg / m ² .

<Coating liquid for undercoat layer formation>
-Polymer compound A having the following structure (weight average molecular weight: 10,000) 0.05 g
・ Methanol 27g
・ Ion exchange water 3g

(Formation of photosensitive layer)
The following photosensitive layer forming coating solution A was prepared and applied on the undercoat layer formed as described above using a wire bar. Drying was performed at 125 ° C. for 34 seconds using a warm air dryer. The coating amount after drying was 1.4 g / m ² .

<Photosensitive layer forming coating solution A>
・ Infrared absorber (IR-1) 0.038 g
-Polymerization initiator A (S-1) 0.061g
-Polymerization initiator B (I-1) 0.094g
・ Mercapto compound (E-1) 0.015 g
・ Polymerizable compound (M-1) 0.425 g
(Product name: A-BPE-4 Shin-Nakamura Chemical Co., Ltd.)
-Binder polymer A (B-1) 0.311g
・ Binder polymer B (B-2) 0.250 g
-Binder polymer C (B-3) 0.062g
・ Additive (T-1) 0.079g
-Polymerization inhibitor (Q-1) 0.0012g
・ Ethyl violet (EV-1) 0.021g
・ Fluorine surfactant 0.0081g
(Megafuck F-780-F Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 5.886g
・ Methanol 2.733g
・ 1-methoxy-2-propanol 5.886 g

  In addition, the infrared absorber (IR-1), polymerization initiator A (S-1), polymerization initiator B (I-1), and mercapto compound (E-1) used for the coating liquid A for forming the photosensitive layer. , Polymerizable compound (M-1), binder polymer A (B-1), binder polymer B (B-2), binder polymer C (B-3), additive (T-1), polymerization inhibitor (Q -1) and the structure of ethyl violet (EV-1) are shown below.

(Formation of lower protective layer)
On the formed photosensitive layer, synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (Goselan CKS-50: saponification degree 99 mol%, polymerization degree 300) , Sulfonic acid-modified polyvinyl alcohol, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), surfactant A (manufactured by Nippon Emulsion Co., Ltd., Emalex 710), and surfactant B (Adeka Pluronic P-84: manufactured by Asahi Denka Kogyo Co., Ltd.) ) Was applied with a wire bar and dried at 125 ° C. for 30 seconds with a hot air dryer.
The content ratio of synthetic mica (solid content) / polyvinyl alcohol / surfactant A / surfactant B in this mixed aqueous solution (coating liquid for forming the lower protective layer) was 7.5 / 89/2 / 1.5. The coating amount (the coating amount after drying) was 0.5 g / m ² .

(Formation of upper protective layer)
On the lower protective layer, an organic filler (Art Pearl J-7P, manufactured by Negami Industrial Co., Ltd.), synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol ( L-3266: degree of saponification 87 mol%, degree of polymerization 300, sulfonic acid-modified polyvinyl alcohol Nippon Synthetic Chemical Industry Co., Ltd.), thickener (Serogen FS-B, Daiichi Kogyo Seiyaku Co., Ltd.), high A mixed aqueous solution (a coating solution for forming an upper protective layer) of molecular compound A (the above structure) and a surfactant (manufactured by Nippon Emulsion Co., Ltd., Emalex 710) is applied with a wire bar, and 125 ° C. using a hot air dryer. For 30 seconds.
The content ratio of the organic filler / synthetic mica (solid content) / polyvinyl alcohol / thickener / polymer compound A / surfactant in the mixed aqueous solution (upper protective layer forming coating solution) is 4.7 / 2. The ratio was 0.8 / 67.4 / 18.6 / 2.3 / 4.2 (mass%), and the coating amount (the coating amount after drying) was 1.2 g / m ² .
As a result, a planographic printing plate precursor of Reference Example 1 was obtained.

[Examples 2 to 20]
In the coating liquid for forming the backcoat layer of Reference Example 1, the addition amount of the epoxy resin was changed as shown in Table 1 below, and the other resins described in Table 1 were used in combination with Reference Example 1 and Similarly, lithographic printing plate precursors of Examples 2 to 20 were obtained.

Other resins described in Tables 1 and 2 are as follows.
・ Rosin modified phenolic resin A: Tamanoru 386 (Arakawa Chemical Structure Co., Ltd.)
・ Rosin modified phenolic resin B: Tamanol 352 (Arakawa Chemical Structure Co., Ltd.)
・ Rosin-modified phenolic resin C: Tamanol 380 (Arakawa Chemical Structure Co., Ltd.)
・ Rosin modified phenolic resin D: Tamanol 409 (Arakawa Chemical Structure Co., Ltd.)
・ Rosin ester: Ester gum HP (Arakawa Chemical Structure Co., Ltd.)
・ Pyrogallol resin: The following structure, weight average molecular weight: 3,000
Novolak resin A: m-cresol / p-cresol = 6: 4 (molar ratio), weight average molecular weight: 4,100
Novolak resin B: phenol / m-cresol / p-cresol = 5: 3: 2 (molar ratio), weight average molecular weight: 5,300
Novolak resin C: phenol / m-cresol / p-cresol = 5: 3: 2 (molar ratio), weight average molecular weight: 30,000

Example 21
A lithographic printing plate precursor of Example 21 was obtained in the same manner as in Example 4 except that the protective layer having a polymerization structure in Example 4 was replaced with a protective layer having a single layer structure formed by the following method.

(Formation of single layer protective layer)
On the photosensitive layer, synthetic mica (Somasif ME-100, 8% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (Goselan CKS-50: saponification degree 99 mol%, polymerization degree 300, sulfonic acid-modified polyvinyl Alcohol Nippon Synthetic Chemical Industry Co., Ltd.) and a surfactant (Nihon Emulsion Co., Emalex 710) mixed aqueous solution (coating solution A for protective layer formation) is applied with a wire bar, and the hot-air drying apparatus is applied. And dried at 125 ° C. for 75 seconds.
The content ratio of synthetic mica (solid content) / polyvinyl alcohol / surfactant in this mixed aqueous solution (coating liquid A for protective layer formation) is 16/82/2 (mass%), and the coating amount is ( The coating amount after drying) was 1.6 g / m ² .

[Example 22]
A lithographic printing plate precursor of Example 22 was obtained in the same manner as in Example 21 except that the protective layer-forming coating solution B obtained by removing synthetic mica from the protective layer-forming coating solution A in Example 21 was used.
The coating liquid B for forming the protective layer has a content ratio of polyvinyl alcohol / surfactant of 98/2 (mass%).

Example 23
In the composition of the backcoat layer-forming coating solution of Reference Example 1, the epoxy resin and other resins used in combination were the same as Reference Example 1 except that the type and content were changed as described in Table 2 below. Similarly, a back coat layer was formed on the aluminum support.
Next, the following photosensitive layer forming coating solution B was applied to the surface of the aluminum support opposite to the surface on which the backcoat layer was formed, so that the thickness after drying was 1.4 μm, and 70 ° C. Was dried for 5 minutes to form a photosensitive layer (photosensitive recording layer).
In this way, a planographic printing plate precursor of Example 23 was obtained.

<Photosensitive layer forming coating solution B>
-Polymer (P-1) 10 parts by mass-Polymerization initiator (BC-6) 2 parts by mass-Polymerization initiator (T-4) 2 parts by mass-Monomer (C-5) 3.5 parts by mass-Infrared absorption Agent (IR-2) 0.5 parts by mass Dye (D-4) 0.3 parts by mass Dioxane 70 parts by mass Cyclohexane 20 parts by mass

Here, the polymer (P-1) used in the coating solution B for forming the photosensitive layer is the polymer obtained in the above Synthesis Example 1, and the monomer (C-5) is the above Synthesis Example. 2 is a monomer obtained in 2.
Moreover, the structure of a polymerization initiator (BC-6), a polymerization initiator (T-4), an infrared absorber (IR-2), and a dye (D-4) is shown below.

[Examples 24-26]
In Example 23, in the composition of the coating liquid for forming the back coat layer, Example 23 except that the type and content of the epoxy resin and other resins used in combination were changed as described in Table 2 below. In the same manner, lithographic printing plate precursors of Examples 24-26 were obtained.

Example 27
The same aluminum plate as used in Reference Example 1 was subjected to surface treatment by electrochemical polishing and anodizing after poly (vinylphosphonic) acid post-treatment to produce an aluminum support.
Next, in the composition of the backcoat layer coating solution of Example 1, the epoxy resin and other resins used in combination were changed to the types and contents as described in Table 2 below, and Reference Example 1 In the same manner as described above, a back coat layer was formed on the above aluminum support.
Next, on the surface of the aluminum support opposite to the surface on which the back coat layer is formed, the following coating solution C for forming a photosensitive layer is applied to a coating amount after drying with a rod wound with a wire to 2 g / m ² . Then, the coating was dried in a Ranar conveyor type oven at about 94 ° C. with a residence time of 60 seconds to form a photosensitive layer (photosensitive recording layer).

<Photosensitive layer forming coating solution C>
-Urethane acrylate A 3.55 mass parts-Sartomer 355 0.74 mass parts-Polymer (P-2) 3.24 mass parts-2- (4-methoxyphenyl) -4,6-
Bis (trichloromethyl) -2-triazine 0.40 parts by mass N-phenyliminodiacetic acid 0.22 parts by mass Infrared absorber (IR-3) 0.08 parts by mass Crystal violet 0.10 parts by mass Byk 307 0.02 parts by mass-methyl ethyl ketone 13.75 parts by mass-toluene 22.91 parts by mass-1-methoxy-2-propanol 54.99 parts by mass

The polymer (P-2) used in the photosensitive layer forming coating solution C is the polymer obtained in Synthesis Example 3 described above.
Details of urethane acrylate A, Sartomer 355, infrared absorber (IR-3), and Byk 307 are as follows.
Urethane acrylate A: obtained by reacting DESMODUR® N100 with hydroxyethyl acrylate and pentaerythritol triacrylate, the double bond content is 0.5 per 100 g after the reaction of the isocyanate groups is completed. 80% methyl ethyl ketone solution of urethane acrylate Sartomer 355: Ditrimethylolpropane tetraacrylate polyfunctional acrylic monomer (Sartomer)
Infrared absorber (IR-3): 2- [2- [2-Triphenyl-3- [2- (1,3-dihydro-1,3,3-trimethyl-2H-indole-2-ylidene) -ethylidene ] -1-cyclohexen-1-yl] -ethenyl] -1,3,3-trimethyl-3H-indolium chloride Byk 307: polyethoxylated dimethylpolysiloxane copolymer (byk Chemie, Wallingford, Conn., USA)

Further, a protective layer having a single layer structure not containing synthetic mica was formed on the photosensitive layer formed as described above in the same manner as in Example 22.
Thus, the planographic printing plate precursor of Example 27 was obtained.

[Examples 28 to 30]
In Example 27, except for changing the type and content of the epoxy resin in the composition of the coating liquid for forming the backcoat layer and other resins used in combination, as described in Table 2 below, Example 27 In the same manner, lithographic printing plate precursors of Examples 28 to 30 were obtained.

[Comparative Example 1]
A lithographic printing plate precursor of Comparative Example 1 was obtained in the same manner as in Reference Example 1, except that the epoxy resin in the coating solution for forming the backcoat layer in Reference Example 1 was replaced with the pyrogallol resin having the above structure.

[Comparative Example 2]
A lithographic printing plate precursor of Comparative Example 2 was obtained in the same manner as in Example 23 except that the epoxy resin and rosin modified phenolic resin A in the coating liquid for backcoat layer in Example 23 were replaced with pyrogallol resin having the above structure. It was.

[Comparative Example 3]
A lithographic printing plate precursor of Comparative Example 3 was obtained in the same manner as in Example 27 except that the epoxy resin and rosin-modified phenol resin A in the coating liquid for backcoat layer in Example 27 were replaced with the pyrogallol resin having the above structure. It was.

[Evaluation]
(1) Observation of planar shape The obtained lithographic printing plate precursor was cut into 61 cm × 50 cm, and the planar shape of the backcoat layer of this sheet was visually observed.
Evaluation was performed by sensory evaluation of 1 to 5, 3 being a practical lower limit level, and 2 or less being a practically impossible level. The results are shown in Tables 1 and 2.

(2) Evaluation of rubbing scratches The obtained lithographic printing plate precursor was cut into 61 cm × 50 cm and laminated without sandwiching interleaf between the 20 sheets to form a laminate. This laminate is shifted 5 cm from the edge onto the same lithographic printing plate precursor already set in the cassette (with 20 stacked plates protruding 5 cm outward from the edge of the plate in the cassette). After the stacking, the edges of the 20 protruding plate materials are pushed in the horizontal direction, and the backcoat layer of the stacked 20 bottom plates is applied to the protective layer surface of the top planographic printing plate precursor in the cassette. It was installed in the cassette while rubbing. A plate material whose surface of the protective layer was rubbed with a backcoat layer was used as a plate material for evaluation of scratch resistance.
The plate material was conveyed from the setting portion to a Trend setter 3244 manufactured by Creo Corporation, and exposed at a resolution of 2400 dpi, a 50% flat screen image at an output of 7 W, an outer drum rotation speed of 150 rpm, and a plate surface energy of 110 mJ / cm ² . After the exposure, neither heat treatment nor water washing treatment was performed, and development was performed at a conveyance speed (line speed) of 2 m / min and a development temperature of 30 ° C. using an automatic developing machine LP-1310HII manufactured by FUJIFILM Corporation. The developer used was a 1: 4 water diluted solution of DH-N, the developer replenisher was diluted 1: 1.4 water of FCT-421, and the finisher was 1: 1 of GN-2K manufactured by FUJIFILM Corporation. A water dilution was used. The presence or absence of scratches generated in the flat screen image of the obtained lithographic printing plate was visually evaluated.
Evaluation was performed by sensory evaluation of 1 to 5, 3 being a practical lower limit level, and 2 or less being a practically impossible level. The results are shown in Tables 1 and 2.

(3) Measurement of static friction coefficient The obtained lithographic printing plate precursor is cut into a sheet of 100 mm × 150 mm, the photosensitive layer side is facing up (the protective layer is facing up), and the surface is placed on a smooth plate of 200 mm × 350 mm Fixed horizontally. Further, the obtained lithographic printing plate precursor was cut into a 35 mm × 75 mm sheet and fixed on a smooth surface of a weight of 500 g having a smooth surface of 35 mm × 75 mm with the back coat layer facing up. The backcoat layer surface of the lithographic printing plate precursor fixed to the weight was placed in contact with the center of the protective layer surface of the lithographic printing plate precursor. In this state, one side of the flat side of the flat plate is lifted and inclined, and the flat plate is inclined when slipping begins between the backcoat layer surface and the protective layer surface of the lithographic printing plate precursor fixed to the weight. The angle θ ° was measured. The static friction coefficient μ was calculated from the relational expression of μ = tan θ. The results are shown in Tables 1 and 2.

As is clear from Tables 1 and 2, the lithographic printing plate precursors of Examples 2 to 30, that is, at least one selected from the group consisting of an epoxy resin , a resin having a phenolic hydroxyl group, and rosin on the back surface of the support. The lithographic printing plate precursor having a backcoat layer containing, the surface shape after drying of the backcoat layer is good, and even when laminated without interposing the interleaf, scratches can be prevented. I understand. Further, the lithographic printing plate precursor in the case where a resin having a rosin or a phenolic hydroxyl group is used in addition to the epoxy resin in the back coat layer, the static friction coefficient between the back coat layer surface and the protective layer surface is 0.40 or more. It seems that there is no sliding between the plates when they are laminated without sandwiching the interleaving paper.
On the other hand, the lithographic printing plate precursors of Comparative Examples 1 to 3 having a back coat layer containing only a pyrogallol resin without an epoxy resin have a high coefficient of static friction, and between each plate when stacked without sandwiching paper. However, the scratch resistance is remarkably inferior.

Claims (10)

A back coat having a photosensitive recording layer on one side of the support , and containing at least one selected from the group consisting of an epoxy resin , a resin having a phenolic hydroxyl group and rosin on the other side of the support A lithographic printing plate precursor having a layer. The lithographic printing plate precursor as claimed in claim 1 , wherein the resin having a phenolic hydroxyl group is a novolac resin or a pyrogallol resin. The lithographic printing plate precursor as claimed in claim 1 or 2 , wherein a content of the resin having a phenolic hydroxyl group is 0.1 to 50% by mass with respect to a total mass of the back coat layer. . The content of the resin having a phenolic hydroxyl group, according to any one of claims 1 to 3, characterized in that 0.5 to 30% by weight, based on the total weight of the backcoat layer Lithographic printing plate precursor. The lithographic printing plate precursor as claimed in claim 1 , wherein the rosin is a rosin-modified phenol resin or a rosin ester. The photosensitive recording layer contains a sensitizing dye, a polymerization initiator, a polymerizable compound, and a binder polymer, and has a protective layer having an oxygen barrier property on the photosensitive recording layer. The lithographic printing plate precursor as claimed in any one of claims 1 to 5 . The lithographic printing plate precursor as claimed in claim 6 , wherein the protective layer contains a filler. The photosensitive recording layer contains an infrared absorber, a polymerization initiator, a monomer having two or more phenyl groups substituted with vinyl groups in the molecule, and a polymer having phenyl groups substituted with vinyl groups in the side chain. The lithographic printing plate precursor as claimed in any one of claims 1 to 5 , wherein: The lithographic printing according to any one of claims 1 to 5 , wherein the photosensitive recording layer contains a binder polymer containing an allyl group of 0.7 meq / g to 8.0 meq / g. Version original edition. The lithographic printing plate precursor according to any one of claims 1 to 9, wherein a plurality of lithographic printing plate precursors are laminated by directly contacting the outermost surface on the photosensitive recording layer side and the outermost surface on the backcoat layer side. Laminate of printing original plate.