JP2003170670A - Original plate for lithographic printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original plate for lithographic printing which enables attainment of a large number of printed matters being improved in printing stain properties and free of a stain even under severe printing conditions and which enables execution of plate making by scanning exposure based on digital signals and is excellent in press developability. <P>SOLUTION: A composition containing a hydrophilic polymer having a polymerizable group is brought into contact with an intermediate layer provided on a base and revealing a polymerization starting power under heating or irradiation of a radiation and, by giving an energy thereto, the hydrophilic polymer having the polymerizable group is chemically bonded to the intermediate layer directly. On the hydrophilic surface thus obtained, a thermal recording layer containing a compound capable of forming a hydrophobic area under heating or irradiation of the radiation is provided. The compound used for the thermal recording layer is preferably a particulate polymer having a heat-reactive functional group (a) or a microcapsule containing a compound having the heat- reactive functional group (b). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative type lithographic printing plate precursor, more specifically, it enables plate making by scanning exposure based on digital signals, has high sensitivity and high printing durability,
The present invention relates to a lithographic printing plate precursor which can give a stain-free printed matter and can be mounted on a printing machine as it is and printed without performing a special development process after image formation.

[0002]

2. Description of the Related Art A number of studies have been conducted on printing plates for computer-to-plate systems, which have made remarkable progress in recent years. Among them, in order to further rationalize the process and solve the problem of waste liquid treatment, a development-free planographic printing plate precursor that can be mounted on a printing machine and printed without being subjected to development processing after exposure has been studied and various A method has been proposed. One of the methods to eliminate the processing step is to mount the exposed printing original plate on the cylinder of the printing machine and supply the dampening water and ink while rotating the cylinder to remove the non-image area of the printing original plate. There is a method called on-press development. That is, this is a method in which the printing original plate is exposed and then mounted on a printing machine as it is, and the processing is completed in a normal printing process.

A lithographic printing plate precursor suitable for such on-press development has a photosensitive layer soluble in dampening water or an ink solvent, and is developed on a printing machine placed in a bright room. It is necessary to have a light room handling property suitable for. For example, in Japanese Patent No. 2938397, on a hydrophilic support,
Disclosed is a lithographic printing plate precursor provided with a heat-sensitive recording layer in which fine particles of a thermoplastic hydrophobic polymer are dispersed in a hydrophilic binder polymer. In this publication, in the lithographic printing plate precursor, infrared laser exposure is carried out to combine fine particles of a thermoplastic hydrophobic polymer by heat to form an image, and then the plate is mounted on a cylinder of a printing machine, dampening water and / or Alternatively, it is described that on-press development can be performed with ink. However, in such a method in which an image is simply formed by coalescing by heat, although the on-press developability is good in the non-image area of the recording layer, the printing durability is poor because the strength in the image area is weak. Will be enough. Further, when a heat-sensitive recording layer is directly provided on a general-purpose aluminum substrate as a substrate of the lithographic printing plate precursor, the heat generated by exposure is taken by the aluminum substrate having high thermal conductivity, and thus the substrate and the heat-sensitive recording layer In the vicinity of the interface with and the thermal energy is sufficient for image formation, that is,
There is a problem that the printing durability is insufficient because the particles are not used for coalescence by heat melting and the image area is not sufficiently cured.

[0004]

SUMMARY OF THE INVENTION The object of the present invention, which takes into consideration the above-mentioned drawbacks of the prior art, is that the on-press developability is good, the image can be formed with high sensitivity, and the printing durability is high. The purpose is to provide a lithographic printing plate precursor exhibiting the property.

[0005]

As a result of various studies to solve the above problems, the present inventors have found that a hydrophilic polymer containing a hydrophilic polymer having a polymerizable group directly chemically bonded to the surface of the support is used. Of a lithographic printing plate, and by providing a heat-sensitive recording layer writable by irradiation of heat or radiation on such a lithographic printing plate support, the sensitivity is high and the stain performance and printing durability are excellent. The present invention has been completed by finding that a lithographic printing plate precursor can be obtained. That is, the lithographic printing plate precursor of the present invention contains a hydrophilic polymer having a polymerizable group on an intermediate layer, which is provided on a substrate and contains a compound that exhibits a polymerization initiation ability by heating or irradiation with radiation. To form a hydrophobic region on the hydrophilic surface obtained by contacting the composition to give energy and directly chemically bonding a hydrophilic polymer having a polymerizable group on the intermediate layer, by heating or irradiating with radiation. It is characterized in that a heat-sensitive recording layer containing a compound capable of being provided is provided. Further, such a compound capable of forming a hydrophobic region by heating or irradiation with radiation includes (a) a fine particle polymer having a heat-reactive functional group or (b) a compound having a heat-reactive functional group. It is characterized by being a microcapsule.

Although the function of the present invention is not clear, since the hydrophilic surface made of the graft polymer is obtained by directly chemically bonding the hydrophilic polymer to the intermediate layer, the hydrophilic polymer has high mobility and excellent hydrophilicity. In addition to exhibiting the property, the bond between the end of the hydrophilic polymer and the intermediate layer is strong and the durability is good, and in particular, the stain prevention function can be maintained for a long period of time in the hydrophilic region which is the non-image area. Even when an aluminum support is used, the intermediate layer formed by binding the hydrophilic polymer functions as a heat insulating layer, and the generated heat does not diffuse to the aluminum substrate and is efficiently used for image formation. It is considered that recording with high sensitivity is possible, the strength of the formed image portion is high, and the printing durability is excellent. In particular, when a hydrophilic polymer having a polymerizable group at the terminal or side chain is used, a graft chain having a branched structure of the hydrophilic polymer is formed on the hydrophilic surface, so that the unit area per unit area is increased. It has the advantage that the density of hydrophilic groups present is increased and the hydrophilicity is dramatically improved over grafts without branching.

[0007]

[Intermediate layer containing a compound exhibiting a polymerization initiation ability by heat or radiation irradiation]

(Hydrophobic Polymer) The intermediate layer containing the compound exhibiting the polymerization initiation ability in the present invention preferably has a hydrophobic polymer as a main component. Hydrophobic polymers applicable to the present invention include polyethylene, polypropylene,
Polystyrene, cellulose diacetate, cellulose triacetate,
Examples thereof include cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polycarbonate, polyvinyl acetal and the like. A mixture of these and a polymerizable compound and a polymerization initiator described below may be coated on any support to form an intermediate layer. It may be used as a layer).

(Compound which exhibits polymerization initiation ability by heating or irradiation of radiation) The intermediate layer in the present invention is a compound which exhibits polymerization initiation ability by applying energy such as heating or irradiation of radiation (hereinafter referred to as "polymerization initiation ability"). It is necessary to add a polymerizable compound). The polymerizable compound used in the intermediate layer has good adhesion to the substrate, and exhibits a polymerizability upon application of energy such as heating or irradiation with radiation, and contains a hydrophilic polymer having a polymerizable group. There is no particular limitation as long as the hydrophilic polymer having the polymerizable group can be added when energy is applied in a state where the composition to be brought into contact with it, but, among others,
A hydrophobic polymer having a polymerizable group in the molecule is preferable.
Specific examples of such a hydrophobic polymer include diene homopolymers such as polybutadiene, polyisoprene, and polypentadiene, allyl (meth) acrylates, and 2
A homopolymer of an allyl group-containing monomer such as allyloxyethyl methacrylate; further, styrene containing a diene monomer such as the above-mentioned polybutadiene, polyisoprene, polypentadiene or an allyl group-containing monomer as a constituent unit, Binary or multi-component copolymers with (meth) acrylic acid ester, (meth) acrylonitrile, etc .; carbon-carbon in the molecule of unsaturated polyester, unsaturated polyepoxide, unsaturated polyamide, unsaturated polyacryl, high density polyethylene, etc. And linear polymers having a double bond or three-dimensional polymers; and the like. In addition, in this specification, when referring to both or either of "acrylic and methacrylic", it may be described as "(meth) acrylic". The content of the polymerizable compound is 10 in terms of solid content.
A range of 99.9% by weight is preferable, and a range of 20 to 50% by weight is particularly preferable.

(Polymerization Initiator) In addition to the polymerizable compound, a polymerization initiator is preferably added to the intermediate layer in order to promote the development of the polymerization initiation ability by applying energy. The polymerization initiator used here is appropriately selected from known thermal polymerization initiators, photopolymerization initiators, etc. capable of expressing the polymerization initiating ability by predetermined energy such as heating or irradiation with radiation. Can be used. Among them, it is preferable to use photopolymerization, which has a higher reaction rate than thermal polymerization, from the viewpoint of manufacturing suitability, and therefore, it is preferable to use a photopolymerization initiator. The photopolymerization initiator that can be used in the present invention is active with respect to actinic rays to be irradiated,
A hydrophobic polymer having a polymerizable group contained in the intermediate layer,
There is no particular limitation as long as it can polymerize (directly chemically bond) with a hydrophilic polymer having a polymerizable group, and examples thereof include a radical polymerization initiator, an anionic polymerization initiator, and a cationic polymerization initiator. Can be used.

Specific examples of such a photopolymerization initiator include p-tert-butyltrichloroacetophenone, 2,2'-diethoxyacetophenone and 2-
Hydroxy-2-methyl-1-phenylpropane-1-
Acetophenones such as on; benzophenone (4,
4'-bisdimethylaminobenzophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone,
Examples thereof include benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and other benzoin ethers; benzyl dimethyl ketal, hydroxycyclohexyl phenyl ketone, and other benzyl ketals.
The content of the polymerization initiator is 0.01 to solid content in the intermediate layer.
A range of 20% by weight is preferable, and a range of 0.1 to 10% by weight is particularly preferable.

(Formation of Intermediate Layer) The intermediate layer used in the present invention is prepared by dissolving the main components such as a hydrophobic polymer, a polymerizable compound, and a polymerization initiator in a solvent and coating the same by a method such as coating. It can be formed by providing it on a material (support) and hardening the film by applying energy such as heating or radiation irradiation. The solvent used at that time is not particularly limited as long as it can dissolve the above components. From the viewpoint of easiness of drying and workability, a solvent having a boiling point not too high is preferable, and specifically, a solvent having a boiling point of about 40 ° C to 150 ° C may be selected. Specifically, acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, methanol, Ethanol, 1-methoxy-2-propanol, 3-methoxypropanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, - such as methoxypropyl acetate. These solvents are
They can be used alone or as a mixture. Then, the concentration of the solid content in the coating solution is appropriately 2 to 50% by weight.

Coating amount when the intermediate layer is formed on the support
Is 0.1 to 20 g / m 2 after drying.²Is preferred
In addition, 1 to 15 g / m²Is preferred. Coating amount 0.
1 g / m ²If it is less than the above, sufficient polymerization initiation ability cannot be expressed, and the parent
Insufficient grafting of the water-based polymer results in desired hydrophilicity
20g / m²Over
However, both are preferable because the film properties tend to deteriorate.
No

As described above, the above-mentioned composition for forming an intermediate layer is arranged on the support base material by coating, etc., and the solvent is removed to form a film to form an intermediate layer. It is preferable that the film is hardened by heating or irradiation with radiation. Particularly, after drying by heating and pre-hardening by irradiation with light, the hydrophobic polymer is cured to some extent in advance, so that after the grafting of the hydrophilic polymer is achieved, the intermediate layer is removed together. This is preferable because the situation can be effectively suppressed. Here, the reason why the light irradiation is used for the pre-curing is for the same reason as described in the section of the photopolymerization initiator. The heating temperature and time may be selected such that the coating solvent can be sufficiently dried, but from the viewpoint of manufacturing suitability, the temperature is 100 ° C. or lower, the drying time is preferably within 30 minutes, and the drying temperature is 40 to 80 ° C. It is more preferable to select a heating condition within a drying time within 10 minutes.

The light irradiation, which is carried out if desired after heating and drying, can be carried out by using a light source used for producing a graft polymer described later, but the formation of the intermediate layer which is carried out subsequently and the activation of the intermediate layer which is carried out by applying energy. From the viewpoint of not inhibiting the formation of the bond between the point and the graft chain, even if the polymerizable compound present in the intermediate layer is partially radically polymerized, it is preferable to irradiate light to such an extent that the radical polymerization does not occur completely, The light irradiation time varies depending on the intensity of the light source, but it is generally preferably 30 minutes or less. As a guideline for such pre-curing, the film residual rate after solvent cleaning is 10% or more, and the initiator residual rate after pre-curing is 1% or more.

[Hydrophilic Surface] (Formation of Hydrophilic Surface) In the lithographic printing plate support of the invention, the surface of the intermediate layer is brought into contact with a hydrophilic polymer having a polymerizable group to impart energy, thereby polymerizing. The hydrophilic polymer having a group can be chemically bonded to the intermediate layer containing the hydrophobic polymer to form a hydrophilic surface which is strong and has excellent durability and high hydrophilicity. The formation of such bonds is called surface grafting. This contact may be carried out by immersing the intermediate layer in a liquid composition containing a polymerizable hydrophilic polymer, but from the viewpoint of handleability and production efficiency of the lithographic printing plate support, As described below, it is preferable to form a layer containing a composition containing a polymerizable hydrophilic polymer as a main component on the surface of the intermediate layer by a coating method.

The formation of a surface graft by applying energy will be described below. In the present invention, the hydrophilic surface is formed by a method called surface graft polymerization. Graft polymerization is a method in which a polymer compound chain is provided with an active species by applying energy by a conventionally known method such as irradiation with heat or radiation, whereby another polymerizable compound which initiates polymerization is further polymerized. , A method of synthesizing a graft (grafting) polymer, particularly when a polymer compound giving an active species forms a surface, it is called surface graft polymerization. Further, the surface graft refers to a surface obtained by grafting a hydrophilic polymer on the surface of the intermediate layer having a polymerization initiation ability.

Usually, the surface of the intermediate layer such as PET constituting the substrate is directly treated with plasma or electron beam,
The graft polymer surface layer, that is, the hydrophilic surface is formed by generating radicals on the surface to express the polymerization initiation ability and then reacting the active surface with a monomer having a hydrophilic functional group. In the above, as described above, by adding a compound having a polymerization initiation ability to the intermediate layer in advance, it becomes possible to easily form such active sites with low energy, and the generated activity Since there are many points, it becomes possible to form a surface having higher hydrophilicity by a simple method.

A known method can be applied to the method itself for causing graft polymerization by light irradiation or the like. As a specific method of the photograft polymerization method, there is disclosed in Japanese Patent Laid-Open No. 63-92
The methods described in JP 658, JP 10-296895 and JP 11-119413 can also be used in the present invention. Specifically, it is a method in which a polysynthetic composition comprising a photoinitiator and a polymerizable compound is pre-coated on a base material in advance, and a hydrophilic polymer having a polymerizable group is brought into contact therewith for irradiation with light. Among the methods for producing a surface graft, it is preferable to use a photografting method in which energy is applied by irradiation with light.

The hydrophilic polymer having a polymerizable group contained in the hydrophilic polymer-containing composition means that an ethylene addition polymerizable unsaturated group such as a vinyl group, an allyl group or a (meth) acryl group is introduced as the polymerizable group. The radical-polymerizable group-containing hydrophilic polymer described above is preferably used. This polymer preferably has a polymerizable group at least at the terminal, and more preferably has a polymerizable group at the terminal and the side chain.

A radical-polymerizable group-containing hydrophilic polymer having such an ethylene addition-polymerizable unsaturated group introduced therein can be synthesized as follows. As a synthesis method, a method of copolymerizing a hydrophilic monomer and a monomer having an ethylene addition-polymerizable unsaturated group, a method of copolymerizing a hydrophilic monomer and a monomer having a double bond precursor, and then treating with a base or the like Examples thereof include a method of introducing a heavy bond and a method of reacting a functional group of a hydrophilic polymer with a monomer having an ethylene addition-polymerizable unsaturated group. Particularly preferred is a method of reacting a functional group of a hydrophilic polymer with a monomer having an ethylene addition polymerizable unsaturated group from the viewpoint of synthesis suitability.

The hydrophilic monomer used in the synthesis of the hydrophilic polymer having the radical polymerizable group at the main chain terminal and / or side chain is (meth) acrylic acid or its alkali metal salt and amine salt, itaconic acid or Its alkali metal salts and amine salts, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, N
-Monomethylol (meth) acrylamide, N-dimethylol (meth) acrylamide, allylamine or its hydrohalide, 3-vinylpropionic acid or its alkali metal salts and amine salts, vinylsulfonic acid or its alkali metal salts and amine salts , 2-
Carboxyl groups such as sulfoethyl (meth) acrylate, polyoxyethylene glycol mono (meth) acrylate, 2-acrylamido-2-methylprobansulfonic acid, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, sulfonic acid groups, phosphoric acid Examples thereof include monomers having a hydrophilic group such as a group, an amino group or a salt thereof, a hydroxyl group, an amide group and an ether group.

Examples of the hydrophilic polymer include hydrophilic homo- or copolymers obtained by using at least one kind selected from the above-mentioned hydrophilic monomers. Further, as the allyl group-containing monomer copolymerizable with the hydrophilic monomer,
Examples include allyl (meth) acrylate and 2-allyloxyethyl methacrylate. In addition, 2- (3-chloro-1-oxopropoxy) ethyl methacrylate is an example of a monomer having a double bond precursor. As a monomer having an addition-polymerizable unsaturated group used for introducing an unsaturated group by utilizing the reaction with a functional group such as a carboxyl group, an amino group or a salt thereof, a hydroxyl group and an epoxy group in a hydrophilic polymer Include (meth) acrylic acid, glycidyl (meth) acrylate, allyl glycidyl eutel, and 2-isocyanatoethyl (meth) acrylate.

Examples of the hydrophilic polymer having a polymerizable group at the terminal or side chain include hydrophilic macromonomers.
The method for producing the macromonomer used in the present invention is described in, for example, Chapter 2, “Synthesis of Macromonomer” in “Chemistry and Industry of Macromonomer” (editor Yuya Yamashita), published by IPC Publishing Bureau on September 20, 1991. Various manufacturing methods are proposed. Particularly useful hydrophilic macromonomers used in the present invention are macromonomers derived from monomers containing a carboxyl group such as acrylic acid and methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and vinyl sterene. Sulfonic acid-based macromonomers derived from monomers of rufonic acid and salts thereof, amide-based macromonomers derived from (meth) acrylamide, N-vinylacetamide, N-vinylformamide, N-vinylcarboxylic acid amide monomers,
Macromonomers derived from hydroxyl group-containing monomers such as hydroxyethyl methacrylate, hydroxyethyl acrylate and glycerol monomethacrylate, and alkoxy or ethylene oxide group-containing monomers such as methoxyethyl acrylate, methoxy polyethylene glycol acrylate and polyethylene glycol acrylate. It is a macromonomer. Also, a monomer having a polyethylene glycol chain or a polypropylene glycol chain can be usefully used as the macromonomer of the present invention.

Among these macromonomers, the useful molecular weight is in the range of 250 to 100,000, and the particularly preferable range is 40.
It is 0 to 30,000. In forming the upper layer, a hydrophilic monomer may be further added to the hydrophilic polymer having a polymerizable group. The polymerization rate can be increased by adding a hydrophilic monomer. The addition amount of the hydrophilic monomer is preferably 0 to 60% by weight. When it is 60% by weight or more, the coating property is poor and uniform coating cannot be performed, which is not suitable.

(Hydrophilic Monomer) As the hydrophilic monomer useful in combination with a hydrophilic polymer having a polymerizable group at the terminal and / or side chain, a monomer having a positive charge such as ammonium or phosphonium, or , A sulfonic acid group, a carboxyl group, a phosphoric acid group, a phosphonic acid group and the like, a monomer having a negative charge or an acidic group capable of dissociating into a negative charge can be mentioned.
Hydroxyl group, amide group, sulfonamide group, alkoxy group,
A hydrophilic monomer having a nonionic group such as a cyano group can also be used. In the present invention, the following monomers can be mentioned as specific examples of hydrophilic monomers that are particularly useful in combination with the hydrophilic polymer.

For example, (meth) acrylic acid or its alkali metal salt and amine salt, itaconic acid or its alkali metal salt and amine salt, allylamine or its hydrohalide salt, 3-vinylpropionic acid or its alkali metal salt. And amine salts, vinyl sulfonic acid or its alkali metal salts and amine salts,
Vinyl styrene sulfonic acid or its alkali metal salt and amine salt, 2-sulfoethylene (meth) acrylate, 3-sulfopropylene (meth) acrylate or its alkali metal salt and amine salt, 2-acrylamido-2-methylprobansulfonic acid Alternatively, an alkali metal salt and an amine salt thereof, acid phosphooxypolyokine ethylene glycol mono (meth) acrylate, allylamine or a hydrohalide thereof, a carboxyl group, a sulfonic acid group, phosphoric acid, an amino group or a salt thereof, A carboxyl group, a sulfonic acid group, a phosphoric acid, an amino group or a salt thereof such as 2-trimethylaminoethyl (meth) acrylate or a hydrohalide thereof can be used. In addition, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, N-monomethylol (meth) acrylamide, N-dimethylol (meth) acrylamide, N-vinylpyrrolidone, N-vinylacetamide,
Allylamine or its hydrohalide, polyoxyethylene glycol mono (meth) acrylate, N
-Methacryloyloxyenalcarbamic acid A monomer such as aspartic acid having an amino acid skeleton in the molecule and a monomer such as glycooxyethyl methacrylate having a sugar skeleton in the molecule are also useful.

The solvent used in the composition containing such a hydrophilic polymer is not particularly limited as long as the above-mentioned hydrophilic macromonomer or hydrophilic monomer, which is the main component, can be dissolved. An aqueous solvent such as
A mixture of these and a solvent to which a surfactant is further added are preferable. Water-soluble solvent refers to a solvent that is miscible with water in any proportion, such water-soluble solvent, for example, methanol, ethanol, propanol,
Examples thereof include alcohol solvents such as ethylene glycol and glycerin, acids such as acetic acid, ketone solvents such as acetone, and amide solvents such as formamide.

The surfactant which can be added to the solvent as required may be one which can be dissolved in the solvent, and examples of such a surfactant include anions such as sodium n-dodecylbenzenesulfonate. -Based surfactants, cationic surfactants such as n-dodecyltrimethylammonium chloride, polyoxyethylene nonylphenol ethers (commercially available products include, for example, Emulgen 910, manufactured by Kao Corporation), polyoxyethylene sorbitan monolaurate. Rate (for commercial products, for example,
Trade name "Tween 20"), non-ionic surfactants such as polyoxyethylene lauryl ether, and the like. When the composition is brought into contact in a liquid state, it can be optionally performed, but the coating amount in the case of forming the hydrophilic polymer composition coating layer by the coating method is 0.1 in terms of solid content.
Preferably to 10 g / m ^2, especially 1 to 5 g / m ² is preferred. 0. If it is less than 1 g / m ² , sufficient surface hydrophilicity cannot be obtained, and if it exceeds 10 g / m ² , it is difficult to obtain a uniform coating film.

(Energy application) There are no particular restrictions on the energy application method when forming a hydrophilic surface on the lithographic printing plate support of the present invention, and active sites are generated on the surface of the intermediate layer to form a polymerizable group. Any method can be used as long as it can impart energy capable of binding to the hydrophilic polymer, but the method of irradiating with actinic ray is preferable from the viewpoint of cost and simplicity of the apparatus. Examples of the energy applying method used for forming the hydrophilic surface in the present invention include a method of heating the entire surface or a method of irradiating a radiation ray such as an entire surface exposure. The preferable exposure and heating conditions for applying energy to the entire surface are appropriately selected based on the point that the polymerization initiator of the compound contained in the intermediate layer and capable of exhibiting the polymerization initiation ability can be expressed and the polymerization initiator can be activated. be able to. As a specific exposure / heating means, for example, an infrared laser,
It is possible to apply UV lamp, light irradiation with visible light, electron beam irradiation such as γ ray, thermal head, heat roll, thermal energy application by using heating zone using non-contact heater or hot air, etc. is there. Examples of these light sources include mercury lamps, metal halide lamps,
There are xenon lamps, chemical lamps, carbon arc lamps, etc. Radiation includes electron beams, X-rays, ion beams, far infrared rays, and the like. In addition, g-line, i-line, Deep-
UV light and high-density energy beam (laser beam) are also used. Lasers used for laser exposure include carbon dioxide gas lasers, nitrogen lasers, Ar lasers, He / Ne lasers, He / Cd lasers, Kr lasers, and other gas lasers, liquid (dye) lasers, ruby lasers, Nd / YAG lasers, and other solid-state lasers. Laser, GaAs / GaAlAs, InGaA
Semiconductor lasers such as s lasers, KrF lasers, XeCl lasers, XeF lasers, excimer lasers such as Ar _{2 and the} like can be mentioned. Of these, exposure with a solid-state high-power infrared laser such as a semiconductor laser or a YAG laser that emits infrared rays having a wavelength of 700 to 1200 nm is preferable. As a specific mode generally used, direct or indirect whole surface heating by a heating device or the like, scanning exposure by an infrared laser,
Suitable examples include high-intensity flash exposure of a xenon discharge lamp or the like, and infrared exposure of an entire surface. Further, when exposing to actinic rays, ultraviolet rays and visible rays are preferable, and ultraviolet rays are particularly preferable from the viewpoint of excellent polymerization rate. Main wavelength of active light is 250 nm or more 8
It is preferably 00 nm or less. Examples of the light source used for the ultraviolet exposure include a low pressure mercury lamp, a high pressure mercury lamp, a fluorescent lamp, a xenon lamp, a carbon arc lamp, a tungsten incandescent lamp, and sunlight. The time required for light irradiation varies depending on the desired degree of hydrophilicity and the light source used, but is usually several seconds to 24 hours.

By thus applying energy to the entire surface of the substrate, the active sites generated in the intermediate layer and the hydrophilic polymer having a polymerizable group are polymerized to form a hydrophilic graft chain having high mobility. A lithographic printing plate support having a surface is obtained. Further, in a preferred embodiment, by excessively adding a hydrophilic polymer having a polymerizable group at the terminal or side chain, the hydrophilic graft chain is further bound to other polymerizable groups of the graft chain bound to the intermediate layer. Or, a graft chain having a branched structure is formed by bonding a plurality of graft chains to the active site of the intermediate layer, and the formation density and mobility of the hydrophilic graft having high mobility are dramatically improved. The higher hydrophilicity is developed.

[Support Substrate] In the lithographic printing plate support of the invention, as described above, the support substrate is a plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, butyrate acetate). Cellulose, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.) may be used as the intermediate layer, but the intermediate layer may also serve as a support, but the intermediate layer as described above may be formed on another desired support. Layers can also be formed. The support (substrate) applicable to the present invention is preferably a dimensionally stable plate-like material,
For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), paper or plastic film laminated or vapor-deposited with the above metals, etc. included. As the support used in the present invention, a polyester film or an aluminum plate is preferable, and among them, a polyester film that can also serve as the intermediate layer and an aluminum plate having good dimensional stability are preferably used.

The lithographic printing plate precursor of the invention can be obtained by providing a heat-sensitive recording layer on the support having the hydrophilic layer. According to the configuration of the present invention, the laser light used for writing is efficiently utilized as the thermal energy required for image formation, and high-sensitivity, high-resolution image formation is possible.
A lithographic printing plate precursor excellent in printability is obtained. [Heat-sensitive recording layer] The heat-sensitive recording layer used in the lithographic printing plate precursor according to the invention is (a) a fine particle polymer having a heat-reactive functional group, or (b) a microparticle containing a compound having a heat-reactive functional group. It is a heat-sensitive recording layer containing a capsule. By using this heat-sensitive recording layer, it is possible to obtain a lithographic printing plate precursor which has excellent on-machine developability and is recordable with radiation in the infrared region.

Examples of the heat-reactive functional group common to the above (a) and (b) include, for example, an ethylenically unsaturated group (eg, acryloyl group, methacryloyl group, etc.) which undergoes a polymerization reaction.
Vinyl group, allyl group), isocyanate group or a block product thereof for addition reaction, functional group having active hydrogen atom as a reaction partner (eg, amino group, hydroxyl group, carboxyl group), epoxy group for addition reaction , An amino group, a carboxyl group or a hydroxyl group which is a reaction partner thereof, a carboxyl group and a hydroxyl group or an amino group which perform a condensation reaction, and an acid anhydride and an amino group or a hydroxyl group which perform a ring-opening addition reaction. The thermoreactive functional group used in the present invention is not limited to these, and may be a functional group that performs any reaction as long as a chemical bond is formed.

First, the fine particle polymer (a) having a heat-reactive functional group will be described. Examples of the heat-reactive functional group suitable for the (a) fine particle polymer include acryloyl group, methacryloyl group, vinyl group, allyl group, epoxy group, amino group, hydroxyl group, carboxyl group, isocyanate group, and acid anhydride group. And groups protecting them. The introduction of the heat-reactive functional group into the polymer fine particles may be performed at the time of polymerizing the polymer, or may be performed by utilizing a polymer reaction after the polymerization.

When the heat-reactive functional group is introduced at the time of polymerizing the polymer, it is preferable to carry out emulsion polymerization or suspension polymerization using a monomer having the heat-reactive functional group. Specific examples of the monomer having a heat-reactive functional group include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, glycidyl methacrylate,
Glycidyl acrylate, 2-isocyanate ethyl methacrylate, blocked isocyanate with its alcohol, 2-isocyanate ethyl acrylate,
Blocked isocyanate with the alcohol, etc., 2
-Aminoethyl methacrylate, 2-aminoethyl acrylate, 2-hydroxyethyl methacrylate, 2-
Examples thereof include hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, and bifunctional methacrylate. The monomer having a thermoreactive functional group used in the present invention is not limited to these.
Examples of the monomer that does not have a heat-reactive functional group and that can be copolymerized with these monomers include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, and vinyl acetate. The monomer having no thermoreactive functional group used in the present invention is not limited to these.

Examples of the polymer reaction used when introducing the heat-reactive functional group after polymerizing the polymer include the polymer reaction described in WO 96/34316.

Among the above-mentioned (a) fine particle polymers having a heat-reactive functional group, from the viewpoint of image forming property, it is preferable that the fine particle polymers are easily fused and united by heat, and the on-press developability is preferable. From the viewpoint of the above, it is particularly preferable that the surface thereof is hydrophilic and dispersible in water. In addition, the contact angle of the film (water droplets in the air) when only the fine particle polymer is applied and dried at a temperature lower than the solidification temperature is the contact of the film when dried at a temperature higher than the solidification temperature. It is preferably lower than the corner (water droplet in the air). In order to bring the hydrophilicity of the fine particle polymer surface to such a preferable state, a hydrophilic polymer or oligomer such as polyvinyl alcohol or polyethylene glycol, or a hydrophilic low molecular weight compound may be adsorbed on the fine particle polymer surface. The surface hydrophilization method of is not limited to these, and various known surface hydrophilization methods can be applied.

The heat fusion temperature of the fine particle polymer (a) having a heat-reactive functional group is preferably 70 ° C. or higher, and more preferably 80 ° C. or higher in view of stability over time. However, if the heat fusion temperature is too high, it is not preferable from the viewpoint of sensitivity. (A) The average particle size of the fine particle polymer is 0.01 to 2
It is preferably 0 μm, but among them 0.05 to
It is more preferably 2.0 μm, and 0.1 to 1.0 μm
It is preferably m. Within this range, good resolution and stability over time can be obtained. The amount of the (a) fine particle polymer added is preferably 50 to 98% by weight of the solid content of the thermosensitive recording layer,
It is more preferably 60 to 95% by weight.

Next, (b) the microcapsule containing the compound having a heat-reactive functional group will be described.
(B) Suitable thermoreactive functional groups for the microcapsules include, in addition to the functional groups mentioned above as common to (a) and (b), for example, polymerizable unsaturated groups, hydroxyl groups, and carboxyl groups. , A carboxylate group, an acid anhydride group, an amino group, an epoxy group, an isocyanate group, an isocyanate block, and the like.

As the compound having a polymerizable unsaturated group,
An ethylenically unsaturated bond, for example, at least one acryloyl group, methacryloyl group, vinyl group, allyl group,
A compound having two or more is preferable.
Such compounds are widely known in the industrial field, and they can be used in the invention without any particular limitation. In chemical form, these are monomers, prepolymers, that is, dimers, trimers and oligomers, or mixtures thereof, and copolymers thereof.

Specific examples include unsaturated carboxylic acids (eg acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid), their esters, and unsaturated carboxylic acid amides. Of these, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohols and amides of unsaturated carboxylic acids and aliphatic polyhydric amines are preferable. Further, an hydroxyl group, an amino group, an addition reaction product of an unsaturated carboxylic acid ester or unsaturated carboxylic acid amide having a nucleophilic substituent such as a mercapto group and a monofunctional or polyfunctional isocyanate or epoxide,
Also, a dehydration condensation reaction product with a monofunctional or polyfunctional carboxylic acid is preferably used. Further, an isocyanate group, an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group, and an addition reaction product of a monofunctional or polyfunctional alcohol, an amine or a thiol,
Further, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving group such as a halogen group or a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. Another preferable example is a compound in which the above unsaturated carboxylic acid is replaced with unsaturated phosphonic acid or chloromethylstyrene.

Among the polymerizable compounds which are esters of unsaturated carboxylic acids and aliphatic polyhydric alcohols, acrylic acid esters include, for example, ethylene glycol diacrylate, triethylene glycol diacrylate, 1,
3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, trimethylolpropane tris (acryloyloxypropyl) ether, trimethylolethane Triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate,
Pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate,
Examples thereof include sorbitol pentaacrylate, sorbitol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, and polyester acrylate oligomer.

As the methacrylic acid ester, for example,
Tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, hexanediol dimethacrylate, penta Erythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p-
Examples include (3-methacryloyloxy-2-hydroxypropoxy) phenyl] dimethylmethane and bis- [p- (methacryloyloxyethoxy) phenyl] dimethylmethane.

Examples of itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, Examples thereof include pentaerythritol diitaconate and sorbitol tetritaconate.

Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of the isocrotonic acid ester include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of the maleic acid ester include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

Other esters include, for example, aliphatic alcohol-based esters described in JP-B-46-27926, JP-A-51-47334 and JP-A-57-196231, and JP-A-59-59. 5240, 59-5241, and JP-A-2-22614.
Those having an aromatic skeleton described in JP-A-9,
The thing containing the amino group described in Unexamined-Japanese-Patent No. 1-165613 is mentioned.

Specific examples of the amide monomer of an aliphatic polyvalent amine compound and an unsaturated carboxylic acid include methylenebis-acrylamide, methylenebis-methacrylamide, 1,6-hexamethylenebis-acrylamide, 1,6- Hexamethylene bis-methacrylamide,
Examples include diethylenetriamine tris acrylamide, xylylene bis acrylamide, and xylylene bis methacrylamide. Other preferable amide-based monomers include, for example, those having a cyclohexylene structure described in JP-B-54-21726.

Further, urethane-based addition-polymerizable compounds produced by addition reaction of isocyanate and hydroxyl group are also suitable, and specifically, for example, JP-B-48-4.
In one molecule obtained by adding an unsaturated monomer having a hydroxyl group represented by the following formula (I) to a polyisocyanate compound having two or more isocyanate groups in one molecule described in Japanese Patent No. 1708. Include urethane compounds containing two or more polymerizable unsaturated groups.

CH ₂ ═C (R ¹ ) COOCH ₂ CH (R ² ) OH (I) (wherein R ¹ and R ² each represent H or CH ₃ ).

Further, urethane acrylates described in JP-A-51-37193, JP-B-2-32293 and JP-A-2-16765, and JP-B-58-49860 and 56-56. 17654 publication,
Urethane compounds having an ethylene oxide skeleton described in JP-A-62-39417 and JP-A-62-39418 are also preferred.

Further, JP-A-63-277653,
63-260909, JP-A-1-105238.
Radical-polymerizable compounds having an amino structure or a sulfide structure in the molecule, which are described in Japanese Patent Laid-Open Publication No. 2003-242, are also preferred.

Other preferred examples include polyester acrylates and epoxy resins as described in JP-A-48-64183, JP-B-49-43191 and JP-A-52-30490. Meta)
Examples thereof include polyfunctional acrylates and methacrylates such as epoxy acrylates reacted with acrylic acid. Also, Japanese Patent Publication No. 46-43946 and Japanese Patent Publication No. 1-403.
Specific unsaturated compounds described in JP-A Nos. 37 and 1-40336 and vinylphosphonic acid compounds described in JP-A No. 2-25493 are also preferable. Further, in some cases, JP-A-61
Compounds containing a perfluoroalkyl group described in JP-A-22048 are also preferable. Furthermore, Journal of Adhesion Society of Japan, Vol. 20, No. 7, p. 300-308 (19
Suitable examples are those introduced as photo-curable monomers and oligomers in 1984).

Suitable epoxy compounds include, for example,
Examples thereof include glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene diglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, bisphenols or polyphenols or hydrogenated polyglycidyl ethers thereof.

Suitable isocyanate compounds include, for example, tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexane phenylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, cyclohexyl diisocyanate,
Alternatively, compounds obtained by blocking them with an alcohol or an amine can be mentioned.

Suitable amine compounds include, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine and polyethyleneimine.

Suitable compounds having a hydroxyl group include, for example, compounds having a terminal methylol group, polyhydric alcohols such as pentaerythritol, and bisphenol / polyphenols. Suitable compounds having a carboxyl group include, for example, pyromellitic acid,
Aromatic polycarboxylic acids such as trimellitic acid and phthalic acid,
Examples thereof include aliphatic polycarboxylic acids such as adipic acid. Suitable acid anhydrides include, for example, pyromellitic acid anhydride and benzophenonetetracarboxylic acid anhydride.

A preferred copolymer of the ethylenically unsaturated compound is, for example, a copolymer of allyl methacrylate. Specific examples include allyl methacrylate / methacrylic acid copolymers, allyl methacrylate / ethyl methacrylate copolymers, and allyl methacrylate / butyl methacrylate copolymers.

As a method of microencapsulation, a known method can be applied. For example, as a method for producing microcapsules, a method utilizing coacervation described in US Pat. Nos. 2,800,457 and 2,800,458, British Patent 99,
No. 0443, U.S. Pat. No. 3,287,154, Japanese Examined Patent Publication No. 38-19574, and No. 42-446.
Precipitation of the polymers described in US Pat. Nos. 3,418,250 and 3,660,304, which are based on the interfacial polymerization method described in U.S. Pat. Method by U.S. Pat. No. 3,796,6
A method using the isocyanate polyol wall material described in US Pat. No. 69, US Pat. No. 3,914,511.
US Pat. No. 4,001,140, US Pat. No. 4,087,376, US Pat. No. 4,087,376, and US Pat. No. 4,089,802.
Urea-formaldehyde-based or urea formaldehyde-resorcinol-based wall forming materials described in U.S. Pat. No. 4,025,445, melamine-formaldehyde resins described in U.S. Pat.
Method using a wall material such as hydroxycellulose, Japanese Patent Publication Sho 3
6-9163 and 51-9079, in situ method by monomer polymerization, British Patent No. 930,422, US Pat. No. 3,111,
No. 407, spray drying method, British Patent Nos. 952,807, 967,
The electrolytic dispersion cooling method described in the specification of No. 074 is mentioned, but the present invention is not limited thereto.

(B) The microcapsule wall preferably used for the microcapsule has three-dimensional cross-linking and has a property of being swollen by a solvent. From this point of view, the wall material of the microcapsules is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, or a mixture thereof, and particularly preferably polyurea and polyurethane. Further, a compound having a heat-reactive functional group may be introduced into the microcapsule wall.

(B) The average particle size of the microcapsules is
It is preferably 0.01 to 20 μm, and 0.05 to
It is more preferably 2.0 μm, and 0.10 to 1.0
It is particularly preferable that the thickness is μm. Within the above range, good resolution and stability over time can be obtained.

(B) In the image forming mechanism using a microcapsule having a heat-reactive functional group, the microcapsule material, the compound encapsulated therein, and the thermosensitive recording layer in which the microcapsule is dispersed are present. Other optional components that react with each other react to form an image area, that is, a hydrophobic area (ink-philic area). For example, a type in which the microcapsules described above are fused by heat, Of the capsule inclusions, the compound exuded to the capsule surface or outside the microcapsules at the time of application,
Alternatively, a compound invading the microcapsule wall from the outside is a type that causes a chemical reaction by heat, or a hydrophilic resin to which the microcapsule material or the encapsulated compound is added, or an added low molecular weight compound. Reacting type, two or more types of microcapsule wall material or inclusions thereof having different functional groups having functional groups capable of thermally reacting with each other are used to react microcapsules with each other. . Therefore, it is preferable for image formation that the microcapsules are fused together by heat, but it is not essential.

The amount of the microcapsules (b) added to the heat-sensitive recording layer is preferably 10 to 60% by weight, and more preferably 15 to 40% by weight, in terms of solid content.
Within the above range, good on-press developability as well as good sensitivity and printing durability can be obtained.

(B) When the microcapsules are added to the heat-sensitive recording layer, a solvent that dissolves the inclusions and swells the wall material can be added to the microcapsule dispersion medium. Such a solvent promotes the diffusion of the encapsulated compound having the heat-reactive functional group to the outside of the microcapsules. Such a solvent depends on the microcapsule dispersion medium, the material of the microcapsule wall, the wall thickness and the inclusions, but can be easily selected from many commercially available solvents. For example, in the case of water-dispersible microcapsules composed of crosslinked polyurea and polyurethane walls, alcohols, ethers, acetals, esters, ketones, polyhydric alcohols, amides, amines, fatty acids and the like are preferable.

Specifically, for example, methanol, ethanol, tert-butanol, n-propanol, tetrahydrofuran, methyl lactate, ethyl lactate, methyl ethyl ketone, propylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, γ-butyl. Examples include, but are not limited to, lactones, N, N-dimethylformamide, N, N-dimethylacetamide. Moreover, you may use together 2 or more types of these solvents.

A solvent that does not dissolve in the microcapsule dispersion but dissolves if the above-mentioned solvent is mixed can be used. The addition amount depends on the combination of the materials, but if it is less than the appropriate value, the image formation becomes insufficient, and if it is more than the appropriate value, the stability of the dispersion liquid deteriorates. Normal,
It is preferably 5 to 95% by weight of the coating solution, and 10 to 9
It is more preferably 0% by mass, particularly preferably 15 to 85% by weight.

[Other Components] In the heat-sensitive recording layer according to the invention, (a) a fine particle polymer having a heat-reactive functional group having image forming property, or (b) a compound having a heat-reactive functional group. In addition to the microcapsules encapsulating, various additives can be used in combination depending on the purpose. (Reaction Initiator, Reaction Accelerator) In the heat-sensitive recording layer according to the present invention, a compound which initiates or accelerates these reactions may be added, if necessary. Examples of the compound that initiates or accelerates the reaction include compounds that generate radicals or cations by heat. Specifically, for example, a lophine dimer, a trihalomethyl compound, a peroxide, an azo compound, an onium salt containing a diazonium salt or a diphenyliodonium salt, an acylphosphine, and an imidosulfonate can be mentioned. These compounds are preferably added in the range of 1 to 20% by weight of the solid content of the thermosensitive recording layer, and more preferably in the range of 3 to 10% by weight. Within the above range, a good reaction initiation effect or reaction acceleration effect can be obtained without impairing the on-press developability.

(Hydrophilic Resin) A hydrophilic resin may be added to the heat-sensitive recording layer of the present invention. The addition of the hydrophilic resin not only improves the on-press developability but also improves the film strength of the heat-sensitive recording layer itself. As a hydrophilic resin,
For example, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl and carboxymethyl are preferable.

Specific examples of the hydrophilic resin include gum arabic, casein, gelatin, starch derivative, carboxymethyl cellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers,
Polyacrylic acids and salts thereof, polymethacrylic acids and salts thereof, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers of hydroxypropyl acrylate and Copolymers, homopolymers and copolymers of hydroxybutyl methacrylate, homopolymers and copolymers of hydroxybutyl acrylate, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and those having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight. Hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyler , May include polyvinyl pyrrolidone, homopolymers and copolymers of acrylamide, homopolymers and polymers of methacrylamide, the N- methylol acrylamide homopolymers and copolymers, and the like. The addition amount of the hydrophilic resin to the heat-sensitive recording layer is preferably 5 to 40% by weight of the solid content of the photosensitive layer,
30% by weight is more preferred. Within this range, good on-machine developability and film strength can be obtained.

(Photothermal Conversion Agent) When an image is formed on the lithographic printing plate precursor according to the invention by scanning exposure with laser light or the like, a photothermal conversion agent for converting light energy into heat energy is added to the lithographic printing plate precursor. It is preferable to contain it. In the lithographic printing plate precursor of the present invention, as the photothermal conversion agent that may be contained, any substance that can absorb light such as ultraviolet rays, visible light rays, infrared rays, and white light rays and can be converted into heat can be used. Examples thereof include carbon black, carbon graphite, pigments, phthalocyanine pigments, metal powders, metal compound powders, and the like. Particularly preferred is wavelength 76
It is a dye, a pigment, or a metal powder or a metal compound powder that effectively absorbs infrared rays of 0 nm to 1200 nm.

Examples of the pigment which can be used as the photothermal conversion agent in the present invention include commercially available pigments and color index (CI) handbooks, "Latest Pigment Handbook" (edited by Japan Pigment Technology Association, 1977), "Latest Pigment". Applied Technology "(CMC
Published in 1986), "Printing Ink Technology", CMC Publishing, published in 1984), and the pigments can be used. The types of pigments include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments,
Examples include green pigments, fluorescent pigments, metal powder pigments, and 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. , Quinophthalone pigment, dyed lake pigment, azine pigment, nitroso pigment, nitro pigment, natural pigment, fluorescent pigment,
Inorganic pigments, carbon black, etc. can be used.

The pigment may be used without surface treatment,
You may perform surface treatment and may use it. Examples of the surface treatment method include a method of surface-coating a hydrophilic resin or a lipophilic resin, a method of attaching a surfactant, and a reactive substance (for example, silica sol, alumina sol, silane coupling agent or epoxy compound, isocyanate compound). ) To the surface of the pigment. The surface treatment method,
It is described in "Properties and Applications of Metal Soap" (Koshobo), "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986). Among these pigments, those that absorb infrared rays are preferable because they are suitable for use in a laser that emits infrared rays. Carbon black is preferable as the pigment that absorbs infrared rays. The particle size of the pigment is preferably in the range of 0.01 to 1 μm, more preferably 0.01 to 0.5 μm.

As dyes, commercially available dyes and literatures (for example, "Dye Handbook" (edited by the Society of Synthetic Organic Chemistry, published in 1970), "Chemical Industry", May 1986, p. 45-
The known dyes described in 51, "Near-infrared absorbing dye", "Development and market trend of 90's functional dye, Chapter 2, Section 2.3 (1990 CMC)" or patents can be used. Specifically, infrared absorbing dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, polymethine dyes, and cyanine dyes are preferable.

Further, for example, JP-A-58-125246
No. 59-84356, No. 60-7878.
Cyanine dyes described in JP-A No. 7-58, JP-A-58-1
No. 73696, No. 58-181690, No. 5
Methine dyes described in JP-A No. 8-194595, JP-A Nos. 58-112793 and 58-224793.
No. 59-48187 and No. 59-7399.
6, gazette 60-52940 gazette, gazette 60-637.
Naphthoquinone dyes described in JP-A-44, etc.
Squarylium dyes described in 8-112792, cyanine dyes described in British Patent 434,875, dyes described in U.S. Pat. No. 4,756,993, U.S. Pat. Fourth 4,973,5
Cyanine dyes described in Japanese Patent No. 72, JP-A-1
Dyes described in JP-A-0-268512, 11
The phthalocyanine compound described in 235883 is mentioned.

Further, as a dye, US Pat. No. 5,156,56
The near-infrared absorption sensitizers described in US Pat. No. 938 are also preferably used, and the substituted arylbenzo (thio) pyrylium salts described in US Pat. No. 3,881,924 are also suitable. Trimethine thiapyrylium salts described in JP-A-57-142645, JP-A-58-
No. 181051, No. 58-220143, No. 59-41363, No. 59-84248,
Pyrylium compounds described in JP-A-59-84249, JP-A-59-146063 and JP-A-59-146061, cyanine dyes described in JP-A-59-216146, U.S. Pat. 283,4
Pentamethine thiopyrylium salt and the like described in Japanese Patent No. 75 and Japanese Patent Publication No. 13514/1993, 5-19714.
Pyrylium compound described in JP-B No. 02, a commercially available product, Eporite III-178 manufactured by Eporin Co.,
Epolite III-130, Epolite III-125
Etc. are also preferably used. Further, examples of other preferable dyes include near-infrared absorbing dyes described as formulas (I) and (II) in US Pat. No. 4,756,993. Some specific examples are shown below.

[0075]

[Chemical 1]

[0076]

[Chemical 2]

Among these dyes, particularly preferable are cyanine dyes, squarylium dyes, pyrylium salts and nickel thiolate complexes.

In the heat-sensitive recording layer according to the present invention, fine metal particles can be used as a photothermal conversion agent. Most of the metal fine particles are light-heat converting and self-heating. As preferable metal fine particles, for example, Si, Al, Ti,
V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y,
Zr, Mo, Ag, Au, Pt, Pd, Rh, In, S
Examples thereof include fine particles of n, W, Te, Pb, Ge, Re and Sb alone or alloys, or oxides or sulfides thereof. More preferably, Ag, Au, Cu, P
It is fine particles of a simple metal of t or Pd or an alloy containing them.

The average diameter of the metal fine particles that can be used in the present invention is
Preferably 1-500 nm, more preferably 1-100
nm, particularly preferably 1 to 50 nm. The degree of dispersion may be polydisperse, but monodisperse with a coefficient of variation of 30% or less is preferable.

The amount of the photothermal conversion agent added to the heat-sensitive recording layer may be up to 30% by weight of the total solid content of the heat-sensitive layer in the case of a pigment or dye. It is preferably 1 to 25% by weight, and particularly preferably 7 to 20% by weight. In the case of a metal fine particle type photothermal conversion agent, 5 to 5 of the total solid content of the image forming material is used.
The amount is about 0% by weight, preferably 10 to 30% by weight, particularly preferably 15 to 20% by weight. Within this range, a good sensitivity improving effect can be obtained.

The photothermal conversion agent may not necessarily be contained in the thermosensitive recording layer, but may be added to, for example, a photothermal conversion layer provided adjacent to the thermosensitive recording layer, or constituting a hydrophilic surface. The intermediate layer and the water-soluble overcoat layer described later may be contained. When at least one of the layers such as the heat-sensitive recording layer, the intermediate layer and the overcoat layer contains the photothermal conversion agent, the infrared absorption efficiency can be increased and the sensitivity can be improved.

(Other Additives) If necessary, various compounds other than the above may be added to the heat-sensitive recording layer in the invention. For example, a polyfunctional monomer can be added to the heat-sensitive recording layer matrix in order to further improve printing durability. As the polyfunctional monomer, those exemplified as the monomer that can be encapsulated in the microcapsules can be used. Particularly preferred monomers include trimethylolpropane triacrylate.

In the heat-sensitive recording layer of the present invention, a dye having a large absorption in the visible light region is used as a colorant for the image in order to make it easy to distinguish the image area from the non-image area after image formation. You can Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink #
312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl. Violet (CI42535), ethyl violet, Rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201).
5) and the like, and dyes described in JP-A No. 62-293247. Further, pigments such as phthalocyanine pigments, azo pigments, and titanium oxide can also be preferably used. The amount added is 0.01 to 10% by weight based on the total solid content of the coating liquid for the thermosensitive recording layer.

Further, in the present invention, it is preferable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the ethylenically unsaturated compound during the preparation or storage of the heat-sensitive recording layer coating solution. . Suitable thermal polymerization inhibitors include, for example, 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-t-butylphenol) and N-nitroso-N-phenylhydroxylamine aluminum salt are mentioned. The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to 5% by mass based on the mass of the entire composition.

If necessary, a higher fatty acid such as behenic acid or behenic acid amide or a derivative thereof is added to prevent polymerization inhibition by oxygen, and the surface of the heat-sensitive recording layer is dried in the drying process after coating. May be unevenly distributed. The amount of higher fatty acid or its derivative added is about 0.1 to about 0.1% of the solid content of the thermosensitive recording layer.
It is preferably about 10% by weight.

If necessary, a plasticizer may be added to the heat-sensitive recording layer in order to impart flexibility to the coating film. Examples of the plasticizer include polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate,
Examples thereof include tricresyl phosphate, tributyl phosphate, trioctyl phosphate, and tetrahydrofurfuryl oleate.

(Formation of Thermosensitive Recording Layer) The thermosensitive recording layer in the present invention is prepared by dissolving or dispersing each of the necessary components described above in a solvent to prepare a coating solution and coating the hydrophilic surface of the support. . As the solvent used here, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-
2-propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N,
N-dimethylformamide, tetramethylurea, N-
Examples thereof include methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone, toluene and water, but are not limited thereto. These solvents are used alone or as a mixture. The solid content concentration of the coating liquid is preferably 1 to 50% by weight.

The coating amount (solid content) of the heat-sensitive recording layer on the support obtained after coating and drying varies depending on the use,
Generally, 0.5 to 5.0 g / m ² is preferable. If the coating amount is less than this range, the apparent sensitivity will be high, but the film characteristics of the heat-sensitive recording layer which functions as an image recording will be deteriorated. Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating and roll coating.

The coating liquid for the heat-sensitive recording layer contains a surfactant for improving the coating property, such as JP-A-62-17095.
Fluorine-based surfactants such as those described in JP-A-0 can be added. The addition amount is preferably 0.01 to 1 mass% of the total solid content of the thermosensitive recording layer, and 0.05 to 1% by mass.
It is more preferably 0.5% by mass.

[Other Constituent Elements] [Overcoat Layer] In the lithographic printing plate precursor according to the invention, a water-soluble overcoat layer is formed on the heat-sensitive recording layer in order to prevent contamination of the surface of the heat-sensitive recording layer with a lipophilic substance. Can be provided. The water-soluble overcoat layer used in the present invention is preferably one that can be easily removed during printing and contains a resin selected from water-soluble organic polymer compounds. As the water-soluble organic polymer compound used here, a film formed by coating and drying has film-forming ability,
Specifically, polyvinyl acetate (however, the hydrolysis rate is 65%
The above), polyacrylic acid and its alkali metal salt or amine salt, polyacrylic acid copolymer and its alkali metal salt or amine salt, polymethacrylic acid and its alkali metal salt or amine salt, polymethacrylic acid copolymer And its alkali metal salts or amine salts, polyacrylamide and its copolymers, polyhydroxyethyl acrylate, polyvinylpyrrolidone and its copolymers, polyvinyl methyl ether, polyvinyl methyl ether / maleic anhydride copolymer, poly-2
-Acrylamido-2-methyl-1-propanesulfonic acid and its alkali metal salts or amine salts, poly-2-
Acrylamido-2-methyl-1-propanesulfonic acid copolymer and its alkali metal salt or amine salt,
Examples thereof include gum arabic, fibrin derivatives (for example, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose and the like) and modified products thereof, white dextrin, pullulan, enzyme-decomposed etherified dextrin and the like. In addition, two or more kinds of these resins may be mixed and used depending on the purpose.

A water-soluble photothermal conversion agent may be added to the overcoat layer. Further, in order to ensure coating uniformity, a nonionic surfactant such as polyoxyethylene nonylphenyl ether or polyoxyethylene dodecyl ether may be added to the overcoat layer in the case of coating with an aqueous solution. . The dry coating amount of the overcoat layer is 0.1 to 2.0 g / m ^2.
Is preferred. Within this range, the on-press developability is not impaired, and good contamination of the surface of the heat-sensitive recording layer due to lipophilic substances such as fingerprint stains can be prevented.

[Plate Making and Printing] The lithographic printing plate precursor of the present invention produced as described above is image-formed by irradiation with heat or radiation. Specifically, direct image-like recording with a thermal recording head, scanning exposure with an infrared laser,
High-intensity flash exposure such as xenon discharge lamp and infrared lamp exposure can be used, but the wavelength is 700 to 1
Exposure with a solid-state high-power infrared laser such as a solid-state laser, a semiconductor laser, or a YAG laser that emits infrared rays of 200 nm is suitable. The image-wise exposed lithographic printing plate precursor according to the invention can be mounted on a printing machine and printed by a usual procedure using ink and fountain solution without any special development treatment. That is, the unexposed portion of the lithographic printing plate precursor after exposure is easily removed by the aqueous component contained in the fountain solution or the like at the initial stage of the printing process to form the non-image portion.

These lithographic printing plate precursors are mounted on a cylinder of a printing machine as described in Japanese Patent No. 2938398, and then exposed by a laser mounted on the printing machine, followed by a fountain solution. It is also possible to perform on-press development by applying ink and / or ink. Further, these lithographic printing plate precursors can also be used for printing after a development treatment using water or a suitable aqueous solution as a developing solution.

Further, the lithographic printing plate precursor of the present invention has a thermosensitive recording layer on a support having a hydrophilic layer having sufficient hydrophilicity and excellent adhesion to a substrate, and therefore has high sensitivity. Since it is recordable and has excellent image forming properties near the support, after exposure, it is attached to the printing machine as it is without any special development processing and printing is performed. It is suitable for so-called on-machine development in which the non-image area is removed by the sexual component.

[0095]

[Example 1]

(Formation of Intermediate Layer) A PET film (M4100 manufactured by Toyobo Co., Ltd.) having a thickness of 0.188 mm was coated with the following photopolymerizable composition as an intermediate layer using a rod bar No. 80.
It was dried at 0 ° C. for 2 minutes. Next, this coated film was irradiated with a 400 W high pressure mercury lamp (UVL-400P, manufactured by Riko Kagaku Sangyo Co., Ltd.) for 10 minutes. The composition used as the intermediate layer has the following composition. -Allyl methacrylate / methacrylic acid polymer (molar ratio 80/20, molecular weight 100,000) 4g-Ethylene oxide modified bisphenol A diacrylate (Toagosei Co., Ltd. M210) 4g-1 -hydroxycyclohexyl phenyl ketone 1.6g-1 -methoxy -2-Propanol 16g

(Synthesis of Hydrophilic Polymer (P-1) Having Polymerizable Group on Side Chain) Polyacrylic acid (average molecular weight 25,
000) 18 g, N, N-dimethylacetamide (D
Hydroquinone 0.41 dissolved in 300 g of MAc)
g, 2-methacryloyloxyethyl isocyanate 1
9.4 g and dibutyltin dilaurate 0.25 g were added and reacted at 65 ° C. for 4 hours. The acid value of the obtained polymer was 7.02 meq / g. The carboxyl group was neutralized with a 1N aqueous sodium hydroxide solution, and the polymer was precipitated by adding it to ethyl acetate and washed well to obtain 18.4 g (P-1) of a hydrophilic polymer having a polymerizable group on its side chain.

(Formation of Hydrophilic Polymer-Containing Layer) The following hydrophilic polymer-containing layer coating solution 1 was applied onto the above-mentioned intermediate layer using a rod bar No. 6, dried at 80 ° C. for 2 minutes, and then 400 W under an argon atmosphere and a high pressure. A mercury lamp (UVL-400P, manufactured by Riko Kagaku Sangyo Co., Ltd.) was used for light irradiation for 30 minutes. The film obtained after light irradiation is thoroughly washed with ion-exchanged water,
A lithographic printing plate support 1 was obtained. [Hydrophilic polymer-containing layer coating solution 1] 2 g of hydrophilic polymer (P-1) containing a polymerizable group in the side chain Water 18 g

(Synthesis of Fine Particle Polymer Having Thermoreactive Functional Group) 7.5 g of allyl methacrylate and 7.5 g of butyl methacrylate were added to a polyoxyethylene nonylphenyl aqueous solution (concentration 9.84 × 10 ⁻³ mol / liter).
00 ml was added, and the system was replaced with nitrogen gas while stirring at 250 rpm. After this solution was heated to 25 ° C., an aqueous cerium (IV) ammonium salt solution (concentration 0.984 × 1
0 ^-3 mol / liter) 10 ml is added. At this time, an ammonium nitrate aqueous solution (concentration 58.8 × 10 ⁻³ mol /
Liter) to adjust the pH to 1.3-1.4.
It was then stirred for 8 hours. The thus obtained liquid had a solid content concentration of 9.5% and an average particle size of 0.4 μm.
It was m.

On the support 1 for a lithographic printing plate described above, the following thermal recording layer coating liquid 1 was coated so that the dry coating amount was 0.5 g / m ^2, and after coating (100 ° C. in an oven). ,
After 60 seconds), the thermosensitive recording layer 1 was provided to obtain the lithographic printing plate precursor of Example 1. (Thermal recording layer coating solution 1) Synthesized fine particle polymer (in terms of solid content) 5 g Polyhydroxyethyl acrylate (weight average molecular weight 25,000) 0.5 g Infrared absorbing dye (IR-11: structure below) 0 .3g water 100g

[0100]

[Chemical 3]

[Example 2] In the formation of the heat-sensitive recording layer in Example 1, an example was used except that the heat-sensitive recording layer coating liquid 2 containing microcapsules encapsulating the compound having the following thermoreactive functional group was used. A lithographic printing plate precursor of Example 2 was obtained in the same manner as in 1. [Synthesis of Microcapsules Encapsulating a Compound Having a Thermoreactive Functional Group] As an oil phase component, 40 g of xylene diisocyanate and 1 of trimethylolpropane diacrylate
0 g, copolymer of allyl methacrylate and butyl methacrylate (molar ratio 7/3) 10 g, Pionine A41C
0.1 g (manufactured by Takemoto Yushi) was dissolved in 60 g of ethyl acetate. 4% of PVA205 (made by Kuraray) as an aqueous phase component
120 g of an aqueous solution was prepared. The oil phase component and the water phase component were emulsified at 10,000 rpm using a homogenizer.
Then, add 40 g of water, and let it stand at room temperature for 30 minutes.
The mixture was stirred at 0 ° C for 3 hours. The microcapsule solution thus obtained had a solid content concentration of 20% and an average particle size of 0.5 μm.

On the same lithographic printing plate support 1 as used in Example 1, the following thermosensitive recording layer coating solution 2 was applied at a dry coating amount of 0.5 g / m ^2, and after coating And dried (100 ° C., 60 sec in oven) to obtain the thermosensitive recording layer 2.
Was provided to obtain a lithographic printing plate precursor of Example 2. (Thermal recording layer coating liquid 2) -Synthesized microcapsules (in terms of solid content) 5 g-Trimethylolpropane triacrylate 3 g-The infrared absorbing dye (IR-11) 0.3 g-Water 60 g-1-Methoxy-2- 40 g of propanol

Example 3 The planographic printing of Example 3 was carried out in the same manner as in Example 1 except that the coating solution 2 for the hydrophilic polymer-containing layer described below was used in the formation of the hydrophilic polymer-containing layer in Example 1. I got the original edition. (Synthesis of Hydrophilic Polymer (P-2) Having Polymerizable Group at Terminal) After dissolving 30 g of acrylamide and 3.8 g of 3-mercaptopropionic acid in 70 g of ethanol, the temperature was raised to 60 ° C. under nitrogen atmosphere to start thermal polymerization. The agent, 2,2-azobisisobutylnitrile (AIBN), 300 mg, was added and the reaction was carried out for 6 hours. After the reaction, the white precipitate was filtered and thoroughly washed with methanol to obtain 30.8 g of a terminal carboxylic acid prepolymer (acid value 0.787 meq / g, molecular weight 1.29 × 1).
0 ^3). 20 g of the obtained prepolymer was dissolved in 62 g of dimethyl sulfoxide, and glycidyl methacrylate 6.
71 g, N, N-dimethyldodecylamine (catalyst) 50
4 mg and hydroquinone (polymerization inhibitor) 62.4 mg were added, and the mixture was reacted under a nitrogen atmosphere at 140 ° C. for 7 hours. The reaction solution was added to acetone to precipitate the polymer, and the polymer was thoroughly washed to obtain a hydrophilic polymer having a polymerizable group at the end (P-2).
[Terminal methacrylate acrylamide macromonomer]
Was obtained (weight average molecular weight: 1.43 × 1)
0 ^3). [Hydrophilic polymer-containing layer coating solution 2] 1 g of a hydrophilic polymer (P-2) containing a polymerizable group at the end, 1 g of acrylamide, 18 g of water

Example 4 An example similar to Example 2 was used except that the hydrophilic polymer-containing layer coating solution 2 used in Example 3 was used in the formation of the hydrophilic polymer-containing layer in Example 2. A lithographic printing plate precursor of No. 4 was obtained.

[Comparative Example 1] A comparative example was carried out in the same manner as in Example 1 except that an aluminum support which had been subjected to surface hydrophilization treatment with silicon described below was used as the support for a lithographic printing plate having a hydrophilic surface. A lithographic printing plate precursor of No. 1 was obtained. (Preparation of hydrophilic aluminum support) An aluminum plate (material JISA1050, thickness: 0.24 mm) was electrolytically grained in a nitric acid bath and anodized in a sulfuric acid bath by a known method, and then treated with an aqueous silicate solution. I went. Ra (center line surface roughness) of the support was 0.25 μm, the amount of anodized film was 2.5 g / m ² , and the amount of silicon deposition was 10 mg / m ² .

[Evaluation of Plate Making and Lithographic Printing Plate] The on-press developable lithographic printing plate precursors obtained in Examples 1 to 4 and Comparative Example 1 described above were manufactured by Creo Inc. equipped with a water-cooled 40 W infrared semiconductor laser. After exposure with a setter 3244VFS, it was attached to the cylinder of a printer SOR-M manufactured by Heidelberg without treatment, and after supplying dampening water, ink was supplied and paper was further supplied to perform printing. The exposure amount required to form an image on each printing plate was measured and used as the recording sensitivity. When printing was performed by exposing with this exposure amount, how many good prints were obtained was measured and used as a guide for printing durability. The results are shown in Table 1 below.

[0107]

[Table 1]

From the above results, it was found that the lithographic printing plate precursor according to the invention was capable of recording with high sensitivity and was excellent in printing durability. On the other hand, Comparative Example 1 using the conventional aluminum hydrophilic support is inferior in both sensitivity and printing durability to those using the hydrophilic surface having the hydrophilic graft polymer having a polymerizable group in the present invention. I found out.

[0109]

According to the present invention, it is an on-press development type lithographic printing plate precursor which can be mounted on a printing machine as it is after exposure and printed. The on-press development property is good and the sensitivity is high. A lithographic printing plate precursor having high printing durability can be obtained.

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Claims (2)

[Claims] 1. A composition containing a hydrophilic polymer having a polymerizable group is brought into contact with an intermediate layer, which is provided on a substrate and contains a compound that exhibits a polymerization initiation ability by heating or irradiation with radiation. , A hydrophilic surface obtained by chemically bonding a hydrophilic polymer having a polymerizable group on the intermediate layer by imparting energy contains a compound capable of forming a hydrophobic region by heating or irradiation with radiation. A lithographic printing plate precursor provided with a thermosensitive recording layer. 2. The compound capable of forming a hydrophobic region by heating or irradiation with radiation is (a) a fine particle polymer having a heat-reactive functional group or (b) a compound having a heat-reactive functional group. The lithographic printing plate precursor according to claim 1, which is a microcapsule to be encapsulated.