JP4991682B2 - Preparation method of lithographic printing plate - Google Patents

Description

  The present invention relates to a method for preparing a lithographic printing plate from a direct heat-sensitive lithographic printing plate precursor. More specifically, the present invention relates to a simple development processing method for producing a lithographic printing plate from a heat-sensitive lithographic printing plate precursor capable of image recording by scanning exposure based on a digital signal.

  In general, a lithographic printing plate is composed of an oleophilic image portion that receives ink in the printing process and a hydrophilic non-image portion that receives dampening water. As such a lithographic printing plate, a PS plate in which an oleophilic photosensitive resin layer is provided on a hydrophilic support has been widely used. The plate making process in the conventional PS plate requires an operation of dissolving and removing the non-image area with a highly alkaline developing solution after exposure, and simplifies or eliminates such additional wet processing. This is one problem that has been desired to be improved with respect to the prior art. Particularly in recent years, disposal of the waste liquid discharged with wet processing has become a major concern for the entire industry due to consideration of the global environment, and the demand for improvement in this aspect has become even stronger.

  On the other hand, as another trend in this field in recent years, digitization technology that electronically processes, stores, and outputs image information using a computer has become widespread. Various new image output methods have been put into practical use. Along with this, a computer that produces a printing plate directly without using a lith film by carrying digitized image information in a high-convergence radiation such as laser light and scanning and exposing the original with this light. To-plate technology is drawing attention.

  Among them, since solid-state lasers such as semiconductor lasers and YAG lasers have recently become available at low cost, plate-making methods using high-power density exposure using high-power lasers are promising. It has come to be. In this method, a large amount of light energy is concentrated on the exposure area during an instantaneous exposure time, and the light energy is efficiently converted into thermal energy, and the heat changes chemical changes, phase changes, forms and structures. A thermal change such as a change is caused and the change is used for image recording. That is, image information is input by light energy such as laser light, but image recording is recorded by a reaction by heat energy. Usually, such a recording method using heat generated by high power density exposure is called heat mode recording, and changing light energy to heat energy is called photothermal conversion.

  Among such heat mode recording lithographic printing plate precursors, one promising method suitable for simple development processing is to image a hydrophilic layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder polymer. This is a heat-sensitive lithographic printing plate precursor for forming a heat-sensitive layer. When heat is applied to the heat sensitive layer, the hydrophobic thermoplastic polymer particles are fused and the surface of the hydrophilic heat sensitive layer is converted into an oleophilic image area.

  For example, in Patent Document 1, Patent Document 2 and Patent Document 3, a lithographic printing plate precursor in which a thermosensitive layer in which fine particles of a thermoplastic hydrophobic polymer are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support. Is disclosed. In these publications, a printing press, dampening water and / or ink are supplied to the lithographic printing plate precursor after infrared laser exposure to form an image by coalescence of thermoplastic hydrophobic polymer particles by heat. It is described that development (so-called development on a printing press) can be performed.

However, it is difficult to sufficiently remove the heat-sensitive layer of the non-image portion containing such thermoplastic hydrophobic fine particles by on-press development with dampening water or oil-based ink. Remains and causes stains in printing.

Japanese Patent No. 2938397 JP-A-9-127683 WO99 / 10186 pamphlet

  Accordingly, an object of the present invention is to provide a method for producing a lithographic printing plate from a lithographic printing plate precursor capable of heat mode recording and simple development. Still another object is to provide a simple development processing method capable of efficiently and reliably removing the heat-sensitive layer in the non-image area of the lithographic printing plate precursor provided with the heat-sensitive layer containing the fine particle polymer. .

In order to solve the above-mentioned problems, the present inventor removed a heat-sensitive layer containing a photothermal conversion agent and a fine particle polymer provided on a support by an automatic processor equipped with a rubbing member in the presence of a processing liquid. The present inventors have found that the plate surface can be efficiently and reliably implemented by rubbing the plate surface with a rubbing member, and the present invention has been completed. That is, the present invention is as follows.
<1> An image is recorded on a lithographic printing plate precursor provided with a thermosensitive layer containing a hydrophilic resin, a photothermal conversion agent, and a fine particle polymer on a support having a hydrophilic surface, and then mounted on a printing press. A method for producing a lithographic printing plate comprising a step of rubbing a plate surface with a rubbing member in the presence of a processing solution by an automatic processor equipped with a rubbing member before removing the heat-sensitive layer in the non-image area. .
<2> The method for producing a lithographic printing plate as described in <1>, wherein the rubbing member is a rotating brush roll.
<3> The hydrophilic resin has at least one of a hydrophilic group of a hydroxyl group, a carboxyl group, a hydroxyethyl group, a hydroxypropyl group, an amino group, an aminoethyl group, an aminopropyl group, and a carboxymethyl group. The method for producing a lithographic printing plate according to <1> or <2>.
<4> The method for preparing a lithographic printing plate as described in any one of <1> to <3>, wherein the photothermal conversion agent is a cyanine dye.
<5> A lithographic printing plate precursor provided with a heat-sensitive layer containing a cyanine dye containing a sulfonate group and a fine particle polymer on a support having a hydrophilic surface is mounted on a printing press after image recording. A method for producing a lithographic printing plate, comprising a step of previously removing a heat-sensitive layer in a non-image area by rubbing the plate surface with a rubbing member in the presence of a processing solution by an automatic processor equipped with a rubbing member.
<6> The method for producing a lithographic printing plate as described in <5>, wherein the rubbing member is a rotating brush roll.
<7> The method for preparing a lithographic printing plate as described in <5> or <6> above, wherein the heat-sensitive layer contains a hydrophilic resin.
<8> The fine particle polymer is melted and coalesced by heat, and after performing image recording for fusing and coalescing the fine particle polymer by heat, it is processed by an automatic processor equipped with a rubbing member by an automatic processor equipped with a rubbing member. The method for producing a lithographic printing plate as described in any one of <1> to <7> above, further comprising a step of rubbing the plate surface with a rubbing member in the presence of a non-image portion to remove the heat-sensitive layer. .
<9> The method for producing a lithographic printing plate as described in <8>, wherein the rubbing member is a rotating brush roll.
The present invention relates to a method for preparing a lithographic printing plate as described in <1> to <9> above, but other matters are also described for reference.

(1) On a support having a hydrophilic surface, a heat-sensitive layer containing a hydrophilic resin, a photothermal conversion agent, and a fine particle polymer , or a heat-sensitive layer containing a cyanine dye containing a sulfonate group and a fine particle polymer was provided. After performing image recording on the lithographic printing plate precursor, it includes a step of rubbing the plate surface with the rubbing member in the presence of the processing liquid and removing the heat-sensitive layer in the non-image area by an automatic processor equipped with the rubbing member. A method for preparing a lithographic printing plate characterized by

The preferred embodiments of the present invention will be further described below.
(2) The method for preparing a lithographic printing plate as described in (1) above, wherein a lithographic printing plate precursor provided with an overcoat layer removable by a treatment liquid is used on the thermosensitive layer.

The lithographic printing plate precursor used in the method of the present invention contains at least a photothermal conversion agent and a fine particle polymer in a heat-sensitive layer on a hydrophilic support, and is heated imagewise or laser-based based on digital signals from a computer or the like. Due to the heat generated by the photothermal conversion of the optical scanning, the fine particle polymer, preferably the fine particle polymer having a heat-reactive functional group, reacts in the image recording portion of the heat-sensitive layer, and melting and fusion occur between the fine particle polymers. When a hydrophilic resin is contained in the heat sensitive layer, the resin becomes hydrophobic by crosslinking and water resistance. The method for preparing a lithographic printing plate of the present invention is to efficiently and efficiently form a heat-sensitive layer in a non-image area by rubbing the lithographic printing plate precursor after heat mode image recording with a rubbing member in the presence of a treatment liquid. An excellent lithographic printing plate that can be surely removed and that can prevent stains at the time of printing and printing can be obtained by a simple development processing method.

  According to the present invention, it is possible to efficiently and reliably remove the heat-sensitive layer in the non-image area of the lithographic printing plate precursor capable of heat mode recording by a simple development processing method. Can be prevented.

The method for preparing the planographic printing plate of the present invention will be described in detail below. A lithographic printing plate precursor to be applied to the method of preparing a lithographic printing plate according to the present invention comprises a heat-sensitive layer or sulfonate containing a hydrophilic resin, a photothermal conversion agent, and a fine particle polymer on a support having a hydrophilic surface. It has a heat-sensitive layer containing a cyanine dye containing a group and a fine particle polymer .
The heat-sensitive layer of the lithographic printing plate precursor used in the present invention contains a fine particle polymer as described above. As described later, the fine particle polymer, preferably a fine particle polymer having a heat-reactive functional group, is used. In addition, it is configured to contain a compound or the like that initiates or accelerates these reactions as necessary, and further contains other components as necessary.

  The method for producing a lithographic printing plate according to the present invention comprises removing the heat-sensitive layer in the non-image area by rubbing the plate surface with a rubbing member in the presence of a treatment liquid after image recording is performed on the lithographic printing plate precursor. Including a process. The removal of the heat-sensitive layer in the non-image area in the present invention can be preferably carried out by an automatic processor equipped with a processing liquid supply means and a rubbing member. Although it does not specifically limit as an automatic processor, The automatic processor which uses a rotating brush roll as a rubbing member is especially preferable. As shown in the layout diagram of the automatic developing processor suitable for the development processing of the present invention in FIG. 1, the processing liquid 10 is sent to the spray pipe 5 by the circulation pump 11, showered, and the rotating brush roll 1 and the plate surface 12 ( The lithographic printing plate is prepared by a process of removing the heat-sensitive layer in the non-image area by an automatic processor that rubs the plate surface 12 with the rotating brush roll 1.

Hereinafter, each configuration of the lithographic printing plate precursor to which the lithographic printing plate preparation method of the present invention is applied will be described.
(Support having a hydrophilic surface)
The support having a hydrophilic surface used in the present invention includes a support that is hydrophilic per se, a support that has been hydrophilized, or a support that has a hydrophilic layer on the support. including.

  The support used in the lithographic printing original plate of the present invention is a dimensionally stable plate-like material, for example, paper, metal laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), metal Plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polystyrene, Polypropylene, polycarbonate, polyvinyl acetal, etc.), plastic film in which a pigment is dispersed, plastic film having a cavity, paper laminated with metal or vapor-deposited metal, or plastic film Etc. are included.

  As a support used for the lithographic printing plate precursor according to the invention, a polyester film or an aluminum plate is preferable. Among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements. Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.

  The surface roughening by the method as described above is preferably performed in such a range that the center line surface roughness (Ha) of the surface of the aluminum plate is 0.3 to 1.0 μm. The roughened aluminum plate is subjected to alkali etching treatment using an aqueous solution of potassium hydroxide or sodium hydroxide as necessary, and further neutralized, and then anodized to increase wear resistance as desired. Processing is performed. As the electrolyte used for anodizing the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. The amount of the anodic oxide film is preferably 1.0 to 5.0 g / m ² , and particularly preferably 1.5 to 4.0 g / m ² . If it is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image part of the lithographic printing plate is likely to be scratched, so-called “scratch stains” where ink adheres to the scratched part during printing. It tends to occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. The hydrophilization treatment used in the present invention is disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are alkali metal silicate (such as aqueous sodium silicate) methods. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, it is disclosed in potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinylphosphonic acid is used.

  When a non-conductive material such as a polyester film is used for the support of the present invention, it is preferable to provide an antistatic layer on the heat-sensitive layer side, the opposite side, or both sides of the support. In the case where the antistatic layer is provided between the support and the hydrophilic layer described later, it contributes to improving the adhesion of the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles and a matting agent are dispersed can be used.

Examples of the material of the metal oxide particles used for the antistatic layer include SiO ₂ , ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , MgO, BaO, MoO ₃ , V ₂ O _5, and these A composite oxide and / or a metal oxide further containing a different atom in these metal oxides can be given. These may be used alone or in combination. As the metal _{oxide, SiO 2, ZnO, SnO 2} , Al 2 O 3, TiO 2, In 2 O 3, MgO is preferred. As an example containing a small amount of hetero atoms, Al or In with respect to ZnO, Sb, Nb or halogen elements with respect to SnO ₂ , and hetero atoms such as Sn with respect to In ₂ O ₃ of 30 mol% or less, preferably 10 What doped the quantity below mol% can be mentioned. The metal oxide particles are preferably contained in the antistatic layer in the range of 10 to 90% by mass. The average particle diameter of the metal oxide particles is preferably in the range of 0.001 to 0.5 μm. The average particle diameter here is a value including not only the primary particle diameter of the metal oxide particles but also the particle diameter of the higher order structure.

The matting agent that can be used for the antistatic layer preferably includes inorganic or organic particles having an average particle size of 0.5 to 20 μm, more preferably an average particle size of 1.0 to 15 μm. . Examples of the inorganic particles include metal oxides such as silicon oxide, aluminum oxide, titanium oxide, and zinc oxide, and metal salts such as calcium carbonate, barium sulfate, barium titanate, and strontium titanate. Examples of the organic particles include cross-linked particles of polymethyl methacrylate, polystyrene, polyolefin, and copolymers thereof. The matting agent is preferably contained in the antistatic layer in the range of 1 to 30% by mass.

  Examples of polymers that can be used for the antistatic layer include proteins such as gelatin and casein, cellulose compounds such as carboxymethylcellulose, hydroxyethylcellulose, acetylcellulose, diacetylcellulose, and triacetylcellulose, dextran, agar, sodium alginate, and starch derivatives. And synthetic polymers such as saccharides such as polyvinyl alcohol, polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester, polystyrene, polyacrylamide, polyvinylpyrrolidone, polyester, polyvinyl chloride, polyacrylic acid and polymethacrylic acid. . The polymer is preferably contained in the antistatic layer in the range of 10 to 90% by mass. The thickness of the antistatic layer is preferably 0.01 to 1 μm.

  In order to make the surface of the support hydrophilic, the hydrophilic layer that can be provided on the support of the present invention includes, for example, an organic hydrophilic matrix obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer. And a layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or an inorganic thin film having a surface containing a metal oxide However, an inorganic thin film having a surface containing an inorganic hydrophilic matrix or metal oxide obtained by sol-gel conversion is preferable.

As the crosslinking reaction used for forming the organic hydrophilic matrix of the hydrophilic layer of the present invention, covalent bond formation by heat or light, or ionic bond formation by a polyvalent metal salt is possible. The organic hydrophilic polymer used in the present invention is preferably a polymer having a functional group that can be used for a crosslinking reaction. Preferred functional groups include, for example, —OH, —SH, —NH ₂ , —NH—, —CO—NH ₂ , —CO—NH—, —O—CO—NH—, —NH—CO—NH—, ^{-CO-OH, -CO-O -} , - CO-O -, -CS-OH, -CO-SH, -CS-SH, -SO 3 H, -SO 2 (O -), - PO 3 H 2 , —PO (O ⁻ ) ₂ , —SO ₂ —NH ₂ , —SO ₂ —NH—, —CH═CH ₂ , —CH═CH—, —CO—C (CH ₃ ) ═CH ₂ , —CO— CH = CH ₂ , —CO—CH ₂ —CO—, —CO—O—CO—, and the following functional groups may be mentioned.

  In particular, a hydroxyl group, an amino group, a carboxyl group, and an epoxy group are preferable.

As such an organic hydrophilic polymer of the present invention, a known water-soluble binder can be used. For example, modified polyvinyl alcohol such as polyvinyl alcohol (polyvinyl acetate having a saponification degree of 60% or more), carboxy-modified polyvinyl alcohol or the like. Alcohol, starch and derivatives thereof, carboxymethylcellulose and salts thereof, cellulose derivatives such as hydroxyethylcellulose, casein, gelatin, gum arabic, polyvinylpyrrolidone, vinyl acetate-crotonic acid copolymer and salts thereof, styrene-maleic acid copolymer And its salts, polyacrylic acid and its salts, polymethacrylic acid and its salts, polyethylene glycol, polyethyleneimine, polyvinylphosphonic acid and its salts, polystyrene sulfonic acid and its salts, poly (methacryloyl) Carboxy acid) and salts thereof, polyvinyl sulfonic acid and salts thereof, poly (methacryloyloxyethyl trimethyl ammonium chloride), polyhydroxyethyl methacrylate, polyhydroxyethyl acrylate, polyacrylamide and the like. These polymers may be copolymers as long as hydrophilicity is not impaired, and may be used alone or in combination of two or more. The amount used is 20% by mass to 99% by mass, preferably 25% by mass to 95% by mass, and more preferably 30% by mass to 90% by mass with respect to the total solid content mass of the hydrophilic layer.

  In the present invention, the organic hydrophilic polymer can be crosslinked with a known crosslinking agent. Known crosslinking agents include polyfunctional isocyanate compounds, polyfunctional epoxy compounds, polyfunctional amine compounds, polyol compounds, polyfunctional carboxyl compounds, aldehyde compounds, polyfunctional (meth) acrylic compounds, polyfunctional vinyl compounds, polyfunctional mercapto compounds. , Polyvalent metal salt compounds, polyalkoxysilane compounds and hydrolysates thereof, polyalkoxytitanium compounds and hydrolysates thereof, polyalkoxyaluminum compounds and hydrolysates thereof, polymethylol compounds, polyalkoxymethyl compounds, etc. It is also possible to add a known reaction catalyst to promote the reaction. The amount used is 1% by mass to 50% by mass, preferably 3% by mass to 40% by mass, and more preferably 5% by mass to 35% by mass with respect to the total solid mass in the coating liquid of the hydrophilic layer. .

  In the system capable of sol-gel conversion that can be used for forming the inorganic hydrophilic matrix of the hydrophilic layer of the present invention, the bonding group coming out of the polyvalent element forms a network structure through oxygen atoms, At the same time, the polyvalent metal also has unbonded hydroxyl groups and alkoxy groups, and is a polymer having a resinous structure in which these are mixed, and is in a sol state when there are many alkoxy groups and hydroxyl groups. As bonding proceeds, the network-like resin structure becomes stronger. In addition, when a part of the hydroxyl group is bonded to the solid fine particles, the surface of the solid fine particles is modified to change the hydrophilicity. The polyvalent binding element of the compound having a hydroxyl group or an alkoxy group that performs sol-gel conversion is aluminum, silicon, titanium, zirconium, and the like. Any of these can be used in the present invention, but the following are most preferably used. A sol-gel conversion system using siloxane bonds that can be formed will be described. Sol-gel conversion using aluminum, titanium, and zirconium can be performed by replacing silicon described below with each element.

  That is, a system including a silane compound having at least one silanol group capable of sol-gel conversion is particularly preferably used. Hereinafter, a system using sol-gel conversion will be further described. The inorganic hydrophilic matrix formed by sol-gel conversion is preferably a resin having a siloxane bond and a silanol group, and a coating liquid which is a sol system containing a silane compound having at least one silanol group is applied. During drying and aging, hydrolysis and condensation of silanol groups proceed to form a siloxane skeleton structure, and gelation proceeds. In addition, the above organic hydrophilic polymer and crosslinking agent are added to the gel structure matrix for the purpose of improving physical performance such as film strength and flexibility, improving coatability, and adjusting hydrophilicity. It is also possible. A siloxane resin forming a gel structure is represented by the following general formula (I), and a silane compound having at least one silanol group is obtained by hydrolysis of a silane compound represented by the following general formula (II): The partial hydrolyzate of the silane compound of the general formula (II) does not necessarily need to be a single hydrolyzate. In general, the silane compound may consist of a partially hydrolyzed oligomer, or a mixed composition of the silane compound and its oligomer. There may be.

The siloxane-based resin of the general formula (I) is formed by sol-gel conversion of at least one silane compound represented by the following general formula (II), and R ^{01 to} R ⁰³ in the general formula (I). At least one of them represents a hydroxyl group, and the other represents an organic residue selected from the symbols R ₀ and Y in the following general formula (II).

Formula (II)
(R ₀ ) _n Si (Y) _4-n

In general formula (II), R ₀ represents a hydroxyl group, a hydrocarbon group or a heterocyclic group. Y represents a hydrogen atom, a halogen atom (representing a fluorine atom, a chlorine atom, a bromine atom or an iodine atom), —OR ₁ , —OCOR ₂ or —N (R ₃ ) (R ₄ ) (R ₁ , R _2). Each represents a hydrocarbon group, R ₃ and R ₄ may be the same or different and each represents a hydrogen atom or a hydrocarbon group), and n represents 0, 1, 2, or 3.

The hydrocarbon group or heterocyclic group represented by R _{0 in} the general formula (II) is, for example, a linear or branched alkyl group having 1 to 12 carbon atoms which may be substituted (for example, a methyl group or an ethyl group). , Propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, etc .; these groups include halogen atoms (chlorine atom, fluorine atom, bromine group) Atom), hydroxy group, thiol group, carboxy group, sulfo group, cyano group, epoxy group, -OR 'group (R' is methyl group, ethyl group, propyl group, butyl group, heptyl group, hexyl group, octyl group) Decyl group, propenyl group, butenyl group, hexenyl group, octenyl group, 2-hydroxyethyl group, 3-chloropropyl group, 2-cyanoethyl group, N, N-dimethylaminoethyl 1-bromoethyl group, 2- (2-methoxyethyl) oxyethyl group, 2-methoxycarbonylethyl group, 3-carboxypropyl group, benzyl group, etc.), -OCOR ″ group (R ″ represents the above R , -COOR ″ group, —COR ″ group, —N (R ′ ″) (R ′ ″) group (R ′ ″ represents a hydrogen atom or R ′ and Represents the same contents, and may be the same or different), —NHCONHR ″ group, —NHCOOR ″ group, —Si (R ″) ₃ group, —CONHR ′ ″ group, —NHCOR ″ group, etc. These substituents may be substituted in plural in the alkyl group),

C2-C12 linear or branched alkenyl group which may be substituted (for example, vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, octenyl group, decenyl group, dodecenyl group, etc. Examples of the group substituted by the group include those having the same contents as the group substituted by the alkyl group), an aralkyl group having 7 to 14 carbon atoms which may be substituted (for example, benzyl group, phenethyl group, 3-phenylpropyl group, naphthylmethyl group, 2-
A naphthylethyl group and the like; examples of the group substituted by these groups include those having the same content as the group substituted by the alkyl group, and a plurality of groups may be substituted).

C5-C10 alicyclic group which may be substituted (for example, cyclopentyl group, cyclohexyl group, 2-cyclohexylethyl group, 2-cyclopentylethyl group, norbornyl group, adamantyl group, etc.) Examples of the group include those having the same content as the substituent of the alkyl group, and may be substituted in plural, or an aryl group having 6 to 12 carbon atoms (for example, phenyl group, naphthyl group). And the substituent may be the same as the group that is substituted with the alkyl group, or may be substituted in plural, or at least one selected from a nitrogen atom, an oxygen atom, and a sulfur atom. A heterocyclic group containing an atom and may be condensed (for example, the heterocyclic ring includes a pyran ring, a furan ring, a thiophene ring, a morpholine ring, a pyrrole ring, and a thiazole ring. An oxazole ring, a pyridine ring, a piperidine ring, a pyrrolidone ring, a benzothiazole ring, a benzoxazole ring, a quinoline ring, a tetrahydrofuran ring, etc., may contain a substituent, such as a group substituted by the alkyl group. And the same contents may be used, and a plurality of them may be substituted).

Examples of the substituent of the —OR ₁ group, —OCOR ₂ group, or —N (R ₃ ) (R ₄ ) group of Y in the general formula (II) represent the following substituents. In the —OR ₁ group, R ₁ is an optionally substituted aliphatic group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, heptyl group, hexyl group, pentyl group, octyl group, Nonyl, decyl, propenyl, butenyl, heptenyl, hexenyl, octenyl, decenyl, 2-hydroxyethyl, 2-hydroxypropyl, 2-methoxyethyl, 2- (methoxyethyloxo) ethyl Group, 1- (N, N-diethylamino) ethyl group, 2-methoxypropyl group, 2-cyanoethyl group, 3-methyloxapropyl group, 2-chloroethyl group, cyclohexyl group, cyclopentyl group, cyclooctyl group, chlorocyclohexyl group , Methoxycyclohexyl group, benzyl group, phenethyl group, dimethoxybenzyl group, methyl base Benzyl group, bromobenzyl group, etc.).

In the —OCOR ₂ group, R ₂ is an aliphatic group having the same contents as R ₁ or an aromatic group having 6 to 12 carbon atoms which may be substituted (the aromatic group is exemplified by the aryl group in R above). The same as the above). In the —N (R ₃ ) (R ₄ ) group, R ₃ and R ₄ may be the same or different from each other, and each is a hydrogen atom or an aliphatic group having 1 to 10 carbon atoms which may be substituted ( for example, represent the like) the same contents as R ₁ -OR ₁ group of said. More preferably, the total number of carbon atoms of R ₃ and R ₄ is 16 or less. Specific examples of the silane compound represented by the general formula (II) include the following, but are not limited thereto.

Tetrachlorosilane, tetrabromosilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra n-propylsilane, tetra t-butoxysilane, tetra n-butoxysilane, dimethoxydiethoxysilane, methyltrichlorosilane, methyltri Bromosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltrit-butoxysilane, ethyltrichlorosilane, ethyltribromosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, Ethyltri-t-butoxysilane, n-propyltrichlorosilane, n-propyltribromosilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, -Propyltriisopropoxysilane, n-propyltri-t-butoxysilane, n-hexyltrichlorosilane, n-hexyltribromosilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltriisopropoxysilane , N-hexyltri-t-butoxysilane, n-decyltrichlorosilane, n-decyltribromosilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, n-decyltriisopropoxysilane, n-decyltrit-butoxy Silane, n-octadecyltrichlorosilane, n-octadecyltribromosilane, n-octadecyltrimethoxysilane, n-octadecyltriethoxysilane, n-octadecyltriisopropoxysilane, n-octadecyltrit-butyl Xysilane, phenyltrichlorosilane, phenyltribromosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, phenyltri-t-butoxysilane, dimethyldichlorosilane, dimethyldibromosilane, dimethyldimethoxysilane, dimethyldi Ethoxysilane, diphenyldichlorosilane, diphenyldibromosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenylmethyldichlorosilane, phenylmethyldibromosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane,

Triethoxyhydrosilane, tribromohydrosilane, trimethoxyhydrosilane, isopropoxyhydrosilane, tri-t-butoxyhydrosilane, vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrit- Butoxysilane, trifluoropropyltrichlorosilane, trifluoropropyltribromosilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltriisopropoxysilane, trifluoropropyltri-t-butoxysilane, γ-glycol Sidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethyl Xysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriisopropoxysilane, γ-glycidoxypropyltri-t-butoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyl Diethoxysila, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriisopropoxysilane, γ-methacryloxypropyltrit-butoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane Γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropyltrit-butoxysilane, γ-mercaptopropylmethyl Methoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltriisopropoxysilane, γ-mercaptopropyltri-t-butoxysilane, β- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and the like.

Along with the silane compound represented by the general formula (II) used for forming the inorganic hydrophilic matrix of the hydrophilic layer of the present invention, it is bonded to a resin during sol-gel conversion of Ti, Zn, Sn, Zr, Al, etc. A metal compound capable of forming a film can be used in combination. Examples of the metal compound used include Ti (OR ₅ ) ₄ (R ₅ is methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, etc.), TiCl ₄ , Ti (CH ₃ COCHCOCH ₃ ) ₂ ( OR ₅ ) ₂ , Zn (OR ₅ ) ₂ , Zn (CH ₃ COCHCOCH ₃ ) ₂ , Sn (OR ₅ ) ₄ , Sn (CH ₃ COCHCOCH ₃ ) ₄ , Sn (OCOR ₅ ) ₄ , SnCl ₄ , Zr (OR ₅ ) ₄ , Zr (CH ₃ COCHCOCH ₃ ) ₄ , Al (OR ₅ ) ₃ , Al (CH ₃ COCHCOCH ₃ ) _{3 and the} like.

Furthermore, in order to promote hydrolysis and polycondensation reaction of the silane compound represented by the general formula (II) and the metal compound used in combination, it is preferable to use an acidic catalyst or a basic catalyst in combination. As the catalyst, an acid or a basic compound is used as it is or in a state in which it is dissolved in a solvent such as water or alcohol (hereinafter referred to as an acidic catalyst and a basic catalyst, respectively). The concentration at that time is not particularly limited, but when the concentration is high, the hydrolysis / polycondensation rate tends to increase. However, when a basic catalyst having a high concentration is used, a precipitate may be generated in the sol solution. Therefore, the degree of the basic catalyst is desirably 1 N (concentration in aqueous solution) or less.

  The type of acidic catalyst or basic catalyst is not particularly limited. Specifically, the acidic catalyst includes hydrogen halides such as hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, hydrogen sulfide, perchloric acid, hydrogen peroxide, carbonic acid, Basic catalysts such as carboxylic acids such as formic acid and acetic acid, substituted carboxylic acids obtained by substituting R in the structural formula represented by RCOOH with other elements or substituents, and sulfonic acids such as benzenesulfonic acid include ammonia water and the like. Examples thereof include ammoniacal bases and amines such as ethylamine and aniline.

  For more details on the above sol-gel method, see Sakuo Sakuo, “Science of Sol-Gel Method”, Agne Jofusha (published) (1988), Satoshi Hirashima “Functional thin film by the latest sol-gel method It is described in detail in books such as "Creation Technology" General Technology Center (published) (1992).

  In addition to the above, in the hydrophilic layer of the organic or inorganic hydrophilic matrix of the present invention, control of the degree of hydrophilicity, improvement of the physical strength of the hydrophilic layer, and dispersibility between the compositions constituting the layer It is possible to add compounds for various purposes such as improvement of coating properties, improvement of coating properties, and improvement of printability. For example, plasticizers, pigments, dyes, surfactants, hydrophilic particles and the like can be mentioned.

  The hydrophilic particles are not particularly limited, but preferably include silica, alumina, titanium oxide, magnesium oxide, magnesium carbonate, calcium alginate and the like. These can be used for promoting hydrophilicity or strengthening the film. More preferably, it is silica, alumina, titanium oxide or a mixture thereof. In the hydrophilic layer of the organic or inorganic hydrophilic matrix of the present invention, it is particularly preferable that metal oxide particles such as silica, alumina and titanium oxide are contained.

  Silica has many hydroxyl groups on the surface, and the inside constitutes a siloxane bond (—Si—O—Si—). In the present invention, silica that can be preferably used is ultrafine silica particles having a particle diameter of 1 to 100 nm dispersed in water or a polar solvent, also referred to as colloidal silica. Specifically, it is described in Toshiro Kaga and Hayashi Hayashi, “Applied Technology of High-Purity Silica”, Volume 3, CMC Co., Ltd. (1991).

  Alumina that can be preferably used is an alumina hydrate (boehmite) having a colloidal size of 5 to 200 nm, an anion in water (for example, a halogen atom ion such as a fluorine ion or a chlorine ion, an acetate ion). Or the like, as a stabilizer. Titanium oxide that can be preferably used is an anatase type or rutile type titanium oxide having an average primary particle size of 50 to 500 nm dispersed in water or a polar solvent using a dispersant as required. is there.

  In the present invention, the average primary particle size of hydrophilic particles that can be preferably used is 1 to 5000 nm, and more preferably 10 to 1000 nm. In the hydrophilic layer of the present invention, these hydrophilic particles may be used alone or in combination of two or more. The amount of use is 5% by mass to 90% by mass, preferably 10% by mass to 70% by mass, and more preferably 20% by mass to 60% by mass with respect to the total solid content mass of the hydrophilic layer.

The hydrophilic layer of the organic or inorganic hydrophilic matrix used in the present invention is supported by dissolving or dispersing in an appropriate solvent such as water, a polar solvent such as methanol or ethanol, or a mixed solvent thereof. It is applied, dried and cured on the body. The coating weight is 0.1-5 g / m ² , preferably 0.3-3 g / m ² , more preferably 0.5-2 g / m ² after drying. If the coating weight after drying of the hydrophilic layer is too lower than 0.1 g / m ^2, it will give undesirable results such as a decrease in retention of hydrophilic components such as fountain solution and a decrease in film strength, and is too high. And the film becomes brittle and gives undesirable results such as a decrease in printing durability.

  The inorganic thin film having a surface containing a metal oxide used for the hydrophilic layer of the present invention is not particularly limited as long as the surface of the thin film is composed of a hydrophilic metal oxide. A thin film of a metal or a metal compound. The metal or metal compound that can be used in the hydrophilic layer of the present invention corresponds to d-block (transition) metal, f-block (lanthanoid) metal, aluminum, indium, lead, tin, silicon and alloys, and respective metals. Metal oxides, metal carbides, metal nitrides, metal borides, metal sulfides, metal halides, which are mixed (including uniform mixed films, non-uniform mixed films and laminated films) It can also be used. In particular, the metal oxide thin film itself is particularly preferable. As the metal oxide thin film, indium oxide, tin oxide, tungsten oxide, manganese oxide, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide and the like and mixed thin films However, it can be suitably used as the hydrophilic layer of the present invention. The thin film surface of the metal and the metal compound is substantially in a highly oxidized state in the atmosphere, and the surface is composed of a metal oxide and can be used in the present invention. In order to ensure the hydrophilicity of the hydrophilic layer, it is essential that the surface of the inorganic thin film that is the hydrophilic layer is composed of a metal oxide. For this reason, after forming a thin film, in order to promote the oxidation of the surface, heat treatment, humidification treatment, glow discharge treatment or the like may be performed. Furthermore, a metal oxide may be laminated on the thin film surface.

  For the thin film formation of the metal or metal compound used for the hydrophilic layer of the present invention, a PVD method (physical vapor deposition method) such as a vacuum vapor deposition method, a sputtering method, an ion plating method or a CVD method (chemical vapor deposition method) is appropriately used. It is done. For example, in the vacuum evaporation method, resistance heating, high frequency induction heating, electron beam heating, or the like can be used as the heating method. Further, as the reactive gas, oxygen or nitrogen may be introduced, or reactive vapor deposition using means such as ozone addition or ion assist may be used.

  In the case of using a sputtering method, a pure metal or a target metal compound can be used as a target material. When pure metal is used, oxygen, nitrogen, or the like is introduced as a reactive gas. As the sputtering power source, a DC power source, a pulse DC power source, or a high frequency power source can be used.

  Prior to the formation of the thin film by the above method, in order to improve the adhesion to the lower layer, the substrate may be degassed by heating the substrate or the surface of the lower layer may be subjected to a vacuum glow process. For example, in the vacuum glow process, a substrate can be processed with the generated plasma by applying a high frequency to the substrate under a pressure of about 1 to 10 mtorr to form a glow discharge. Further, the effect can be improved by increasing the applied voltage or introducing a reactive gas such as oxygen or nitrogen.

  As for the thickness of the thin film of the metal or metal compound which has a hydrophilic surface used for the hydrophilic layer of this invention, 10 nm-3000 nm are preferable. More preferably, it is 20-1500 nm. If it is too thin, unfavorable results such as a decrease in dampening water retention and a decrease in film strength are given. If it is too thick, it takes time to form a thin film, which is not preferable in terms of production suitability.

  When the hydrophilic layer is provided on the support of the present invention, the surface on the hydrophilic layer side of the support is subjected to sandblasting or the like from the viewpoint of improving the surface area of the hydrophilic layer or improving adhesion with the upper layer. Surface modification treatment such as roughening treatment or corona treatment may be performed.

  The lithographic printing plate precursor according to the present invention is obtained by providing the heat-sensitive layer of the present invention on the hydrophilic surface of a support. If necessary, a water-soluble metal salt such as zinc borate is provided between them. An inorganic undercoat layer or an organic undercoat layer can be provided. Various organic compounds are used as the organic subbing layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and optionally substituted phenylphosphones. Acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, organic phosphonic acid such as methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphonic acid, alkylphosphoric acid and glycerophosphoric acid Of organic phosphinic acids such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and triethanolamine Hides such as hydrochloride -Alanine, and hydrochlorides of amines having a carboxy group, may be used by mixing two or more.

This undercoat layer can be provided by the following method. That is, a method in which a solution obtained by dissolving the above organic compound in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is applied to the hydrophilic surface of the support and dried, and water or methanol, The substrate is adsorbed by immersing the support in a solution in which the above organic compound is dissolved in an organic solvent such as ethanol or methyl ethyl ketone or a mixed solvent thereof, and then the organic undercoat layer is formed by washing and drying with water or the like. It is a method of providing. In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. The coating amount of the undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . From the viewpoint of preventing blocking, the support used in the present invention preferably has a maximum roughness depth (Rt) of at least 1.2 μm on the back surface of the support, and further, the back surface of the support (that is, The dynamic friction coefficient (μk) when the back surface of the lithographic printing plate precursor of the present invention slides on the surface of the lithographic printing plate precursor of the present invention is preferably 2.6 or less.

  The thickness of the support used in the present invention is about 0.05 mm to 0.6 mm, preferably 0.1 mm to 0.4 mm, and particularly preferably 0.15 mm to 0.3 mm.

(Thermosensitive layer)
The heat-sensitive layer of the present invention contains a fine particle polymer. The fine particle polymer that can be used in the present invention is preferably one in which the fine particle polymers melt and coalesce with heat, and the surface thereof is particularly hydrophilic and is preferably dispersed in water. For example, polyethylene, polystyrene, polyvinyl chloride, Examples thereof include vinylidene chloride, poly (meth) methyl acrylate, poly (meth) ethyl acrylate, poly (meth) acrylate butyl, polyacrylonitrile, polyvinyl acetate, and latexes of copolymers thereof. In order to make the fine particle polymer surface hydrophilic in this way, hydrophilic polymers or oligomers such as polyvinyl alcohol and polyethylene glycol, or hydrophilic low molecular weight compounds may be adsorbed on the fine particle polymer surface. It is not limited to.

  In addition, the contact of the film when the contact angle (water droplets in the air) produced by applying only fine particle polymer and drying at a temperature lower than the solidification temperature is dried at a temperature higher than the solidification temperature. It is preferably lower than the angle (water droplets in the air), and the solidification temperature of the fine particle polymer is preferably 70 ° C. or higher, but more preferably 100 ° C. or higher in view of stability over time.

Furthermore, the fine particle polymer of the present invention preferably has a heat-reactive functional group for the purpose of improving the film strength of the image area. As the fine particle polymer having a heat-reactive functional group, any polymer having a functional group capable of reacting with a functional group present in another fine particle polymer or a functional group present in another component in the heat-sensitive layer is used. Although not limited, the latex etc. which contain these functional groups can be mentioned.

  These fine-particle polymers may react with each other through functional groups, and if they contain a hydrophilic resin or a low-molecular compound described later as another additive in the heat-sensitive layer, they react with them. May be. Further, two or more kinds of fine-particle polymers may be allowed to react with each other by imparting different functional groups that thermally react with each other.

  Examples of the thermally reactive functional group include an ethylenically unsaturated group that undergoes a polymerization reaction (eg, acryloyl group, methacryloyl group, vinyl group, and allyl group), an isocyanate group that undergoes an addition reaction, or a block thereof, and a reaction thereof. Functional group having active hydrogen atom as a partner (for example, amino group, hydroxyl group, carboxyl group, etc.), epoxy group that similarly performs addition reaction, amino group, carboxyl group or hydroxyl group that is the reaction partner, condensation reaction is performed Examples thereof include a carboxyl group and a hydroxyl group or amino group, an acid anhydride that performs a ring-opening addition reaction, an amino group, or a hydroxyl group. However, any functional group capable of performing any reaction may be used as long as a chemical bond is formed.

  The fine particle polymer having a heat-reactive functional group used in the heat-sensitive layer of the present invention includes acryloyl group, methacryloyl group, vinyl group, allyl group, epoxy group, amino group, hydroxyl group, carboxyl group, isocyanate group, and acid anhydride. And those having a group protecting them. Introduction of these functional groups into the polymer particles may be performed at the time of polymerization, or may be performed using a polymer reaction after the polymerization.

  When introduced at the time of polymerization, it is preferable to carry out emulsion polymerization or suspension polymerization of the monomer having these functional groups. Specific examples of monomers having such functional groups include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2-isocyanate ethyl methacrylate, block isocyanates based on alcohols thereof, 2-isocyanate ethyl acrylate, and the like. Block isocyanate with alcohol, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, bifunctional methacrylate However, it is not limited to these.

  Examples of the monomer having no heat-reactive functional group that can be copolymerized with these monomers include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, and vinyl acetate. The monomer is not limited as long as it has no monomer. Examples of the polymer reaction used when the introduction of the heat-reactive functional group is performed after the polymerization include a polymer reaction described in WO96-34316.

  Among the fine particle polymers having the above-mentioned heat-reactive functional groups, those in which the fine particle polymers are fused and coalesced by heat are preferred, but a hydrophilic resin added between the fine particle polymers or added with the fine particle polymer by causing a chemical reaction by heat, Alternatively, if a chemical bond is formed with the added low molecular weight compound and a strong film can be formed, it is preferable in terms of image formation that the fine particle polymer is melted and merged with heat, but it is not essential.

  The average particle size of the fine particle polymer of the present invention is preferably 0.01 to 20 μm, more preferably 0.05 to 2.0 μm, and particularly preferably 0.1 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.

  The addition amount of the fine particle polymer is preferably 50% by mass or more, more preferably 60% by mass or more, based on the solid content of the heat sensitive layer.

  In the case of using the fine particle polymer having a heat-reactive functional group as described above for the heat-sensitive layer of the present invention, a compound that initiates or accelerates these reactions may be added as necessary. Examples of the compound that initiates or accelerates the reaction include compounds that generate radicals or cations by heat, such as lophine dimer, trihalomethyl compound, peroxide, azo compound, diazonium salt, or diphenyliodonium salt. And onium salts, acylphosphine, imide sulfonate and the like. These compounds can be added in the range of 1 to 20% by mass of the heat-sensitive layer solid content. Preferably it is the range of 3-10 mass%. Within this range, good reaction initiation or acceleration effect can be obtained without impairing developability.

A hydrophilic resin may be added to the heat-sensitive layer of the present invention . By adding a hydrophilic resin, not only the developability is improved, but also the film strength of the thermosensitive layer itself is improved. As the hydrophilic resin, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl and the like are preferable.

  Specific examples of hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and Salts thereof, polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, hydroxybutyl Homopolymers and copolymers of methacrylate, homopolymers and copolymers of hydroxybutyl acrylate Homopolymers of limers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight And copolymers, methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, and the like.

  The amount of the hydrophilic resin added to the heat-sensitive layer is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the solid content of the heat-sensitive layer. Within this range, good developability and film strength can be obtained.

The lithographic printing plate precursor according to the present invention includes a photothermal conversion agent contained in a heat-sensitive layer or a layer adjacent thereto (hydrophilic layer, undercoat layer or an overcoat layer described later), thereby irradiating with a laser beam or the like. Image recording is possible. The lithographic printing plate precursor according to the invention contains a photothermal conversion agent at least in the heat-sensitive layer.
As such a photothermal conversion agent, any substance that absorbs the wavelength of the laser light source may be used, and various pigments, dyes, and metal fine particles can be used. In particular, a light absorbing material having an absorption band in at least a part of 700 to 1200 nm is preferable.

  Examples of the pigment include black pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded pigments. 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.

  These pigments may be used without surface treatment, or may be used after surface treatment. Surface treatment methods include surface coating with a hydrophilic resin or lipophilic resin, a method of attaching a surfactant, a reactive substance (eg, silica sol, alumina sol, silane coupling agent, epoxy compound, isocyanate compound, etc.) A method of bonding to the pigment surface is conceivable. 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. Among these pigments, those that absorb infrared rays are preferable because they are suitable for use in lasers that emit infrared rays. Carbon black is preferable as the pigment that absorbs infrared rays. The particle diameter of the pigment is preferably in the range of 0.01 μm to 1 μm, and more preferably in the range of 0.01 μm to 0.5 μm.

  Examples of the dye include commercially available dyes and literature (for example, “Dye Handbook” edited by the Society for Synthetic Organic Chemistry, published in 1970, “Chemical Industry”, May 1986, P. 45-51, “Near Infrared Absorbing Dye”, “90 Development and market trends of age functional pigments "Chapter 2. 2.3 (1990) CMC) or known dyes described in patents can be used. Specifically, infrared absorbing dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, polymethine dyes, and cyanine dyes are preferable.

  Further, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, JP Methine dyes described in JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, JP-A-58-224793, JP-A-59-48187 Naphthoquinone dyes described in JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., and JP-A-58-112792 Squarylium dye, cyanine dye described in British Patent 434,875, dye described in US Pat. No. 4,756,993, US Pat. No. 4,973,572 Cyanine dyes, dyes in JP-A 10-268512 JP, may be mentioned phthalocyanine compound of the JP-11-235883 discloses described.

  Further, near-infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzo (thio) pyrylium described in US Pat. No. 3,881,924. Salt, trimethine thiapyrylium salt described in JP-A No. 57-142645, JP-A Nos. 58-181051, 58-220143, 59-41363, 59-84248, 59- 84249, 59-146063, 59-146061, pyrylium compounds described in JP-A-59-216146, cyanine dyes described in US Pat. No. 4,283,475 Pentamethine thiopyrylium salts, and the pyrylium compounds described in JP-B-5-13514 and JP-A-5-19702, Porin Co. Epolight III-178, Epolight III-130, Epolight III-125 and the like is also preferably used. Some specific examples are shown below.

  The organic photothermal conversion agent can be added up to 30% by mass in the heat sensitive layer. Preferably it is 5-25 mass%, Most preferably, it is 7-20 mass%. Within this range, good sensitivity can be obtained.

In the heat-sensitive layer of the present invention, metal fine particles can also be used as a photothermal conversion agent. Most of the metal fine particles are photothermal convertible and self-heating, but preferable metal fine particles include Si, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr. , Mo, Ag, Au, Pt, Pd, Rh, In, Sn, W, Te, Pb, Ge, Re, and Sb, or oxide or sulfide fine particles thereof. Among the metals constituting these metal fine particles, preferred metals are those that are likely to coalesce by heat when irradiated with light, have a melting point of about 1000 ° C. or less, and have absorption in the infrared, visible, or ultraviolet region, such as Re, Sb, Te, Au, Ag, Cu, Ge, Pb and Sn. Particularly preferred are metal fine particles such as Ag, Au, Cu, Sb, Ge and Pb, which have a relatively low melting point and a relatively high absorbance to infrared rays, and the most preferred elements are Ag, Au and Cu. Is mentioned.

  Also, for example, fine particles of low melting point metal such as Re, Sb, Te, Au, Ag, Cu, Ge, Pb, Sn, and fine particles of self-heating metal such as Ti, Cr, Fe, Co, Ni, W, Ge Or a mixture of two or more photothermal conversion substances. In addition, it is also preferable to use a combination of a metal-type micropiece with a particularly large light absorption when combined with other metal micro-pieces such as Ag, Pt, and Pd.

  The particle diameter of these particles is preferably 10 μm or less, more preferably 0.003 to 5 μm, and particularly preferably 0.01 to 3 μm. Within this range, good sensitivity and resolution can be obtained.

  In the present invention, when these metal fine particles are used as a photothermal conversion agent, the amount added is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 30% by mass or more, based on the solid content of the heat-sensitive layer. Used in High sensitivity is obtained within this range.

  In the heat-sensitive layer of the present invention, when the fine particle polymer having the heat-reactive functional group as described above is used, a functional group capable of reacting with the heat-reactive functional group in the fine particle polymer and a protective group thereof The low molecular compound which has can be contained. The addition amount of these compounds is preferably 5% by mass to 40% by mass in the thermosensitive layer, and particularly preferably 5% by mass to 20% by mass. If it is less than this, the crosslinking effect is small and the printing durability is insufficient, and if it is more than this, the developability after aging deteriorates. The compounds usable for these will be described below.

  The low molecular compound has a polymerizable unsaturated group, hydroxyl group, carboxyl group, carboxylate group, acid anhydride group, amino group, epoxy group, isocyanate group, and blocked isocyanate group in the molecule. A compound can be mentioned.

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

  Specific examples of the radical polymerizable compound that is 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, and 1,3-butanediol diacrylate. , 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, etc. is there.

  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, and JP-A-59-5240. Those having an aromatic skeleton described in JP-A-59-5241, JP-A-2-226149, and those containing an amino group described in JP-A-1-165613 are also preferably used.

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 No. 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 urethane compound containing two or more polymerizable unsaturated groups in one molecule obtained by adding an unsaturated monomer having a hydroxyl group represented by the following formula (A) to a polyisocyanate compound having two or more isocyanate groups. Etc.

Formula (A)
CH ₂ ═C (R _m ) COOCH ₂ CH (R _n ) OH (where R _m and R _n represent H or CH ₃ )

  Also, urethane acrylates as described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 Urethane compounds having an ethylene oxide skeleton described in JP-A No. 62-39417 and JP-B No. 62-39418 are also suitable. Furthermore, by using radically 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. Also good.

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

  As the epoxy compound, preferably glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene diglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, bisphenols or polyphenols or hydrogenated polyglycidyl ether Etc.

  The compound having an isocyanate is preferably tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexanephenylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, cyclohexyl diisocyanate or alcohols or amines thereof. The compound blocked with can be mentioned.

As the amine compound, ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, polyethyleneimine and the like are preferably used. Preferred examples of the compound having a hydroxyl group include compounds having terminal methylol, polyhydric alcohols such as pentaerythritol, bisphenols and polyphenols, and the like. Preferred examples of the compound having a carboxyl group include aromatic polyvalent carboxylic acids such as pyromellitic acid, trimellitic acid, and phthalic acid, and aliphatic polyvalent carboxylic acids such as adipic acid. Preferable examples of the acid anhydride include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.

  In addition to the above, various compounds may be added to the heat-sensitive layer of the present invention as necessary. For example, a dye having a large absorption in the visible light region can be used as an image colorant in order to make it easy to distinguish between an image area and a non-image area after image formation. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc. And dyes described in No. 293247. Further, pigments such as phthalocyanine pigments, azo pigments, and titanium oxide can also be suitably used. The addition amount is preferably 0.01 to 10% by mass with respect to the total solid content of the heat-sensitive layer coating solution. Furthermore, it is preferable to add a coloring or decoloring compound in the heat-sensitive layer of the present invention in order to sharpen the image area and the non-image area when exposed. For example, leuco dyes (leucomalachite green, leuco crystal violet, crystal violet lactone, etc.) and pH-changing dyes (eg ethyl violet, Victoria Poor Blue BOH, etc.) together with thermal acid generators such as diazo compounds and diphenyliodonium salts Dyes).

  In the present invention, it is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the ethylenically unsaturated compound during preparation or storage of the heat sensitive layer coating solution. 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-t-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to 5% by mass with respect to the mass of the whole composition.

  If necessary, higher fatty acids such as behenic acid and behenic acid amide or derivatives thereof are added to prevent polymerization inhibition by oxygen, and are unevenly distributed on the surface of the heat-sensitive layer in the drying process after coating. Also good. The amount of the higher fatty acid or derivative thereof added is preferably about 0.1 to about 10% by mass of the heat-sensitive layer solid content.

  Furthermore, a plasticizer can be added to the heat-sensitive layer of the present invention, if necessary, in order to impart flexibility of the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate and the like are used.

The heat-sensitive layer of the present invention is applied by preparing a coating solution by dispersing or dissolving the necessary components described above in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Ethane, methyl lactate, ethyl lactate, N
, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, etc., but are not limited thereto. Absent. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

Moreover, although the heat sensitive layer coating amount (solid content) on the support obtained after application | coating and drying changes with uses, generally 0.4-5.0 g / m < ² > is preferable. When the coating amount is less than this range, the apparent sensitivity increases, but the film characteristics of the heat-sensitive layer that performs the function of image recording deteriorate. 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.

  A surfactant for improving the coating property, for example, a fluorine-based surfactant described in JP-A-62-170950 can be added to the heat-sensitive layer coating solution. A preferable addition amount is 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass, based on the total solid content of the heat-sensitive layer.

(Overcoat layer)
In the lithographic printing plate precursor of the present invention, an overcoat layer can be provided on the heat-sensitive layer in order to prevent contamination and scratches by the lipophilic substance on the surface of the heat-sensitive layer. The overcoat layer used in the present invention can be easily removed with a hydrophilic printing liquid such as dampening water during printing, and contains a resin selected from hydrophilic organic polymer compounds. As the hydrophilic organic polymer compound used here, a film formed by drying has a film-forming ability. Specifically, polyvinyl acetate (however, a hydrolysis rate of 65% or more), polyacrylamine salt , Polyacrylic acid copolymer, alkali metal salt or amine salt thereof, polymethacrylic acid, alkali metal salt or amine salt thereof, polymethacrylic acid copolymer, alkali metal salt or amine salt thereof, polyacrylamide, copolymer thereof , Polyhydroxyethyl acrylate, polyvinyl pyrrolidone, copolymer thereof, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl-1-propanesulfonic acid, alkali metal salt thereof, or Amine salt, poly-2-acrylamide-2-methyl -1-Propanesulfonic acid copolymer, alkali metal salt or amine salt thereof, gum arabic, fiber derivative (for example, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.), modified product thereof, white dextrin, pullulan, enzyme Decomposed etherified dextrin and the like can be mentioned. Further, two or more kinds of these resins can be mixed and used depending on the purpose.

In addition, the hydrophilic photothermal conversion agent may be added to the overcoat layer. Furthermore, in order to ensure the uniformity of coating, a nonionic surfactant such as polyoxyethylene nonylphenyl ether or polyoxyethylene dodecyl ether can be added to the overcoat layer in the case of aqueous solution coating. . The dry coating amount of the overcoat layer is preferably 0.1 to 2.0 g / m ² . Within this range, developability is not impaired, and the surface of the heat-sensitive layer can be satisfactorily prevented from being contaminated or scratched by an oleophilic substance such as a fingerprint adhering stain.

(Image formation and plate making)
The lithographic printing plate precursor of the present invention is image-formed by heat. Specifically, direct image-like recording by a thermal recording head or the like, scanning exposure by an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, or the like is used, but a semiconductor that emits infrared light having a wavelength of 700 to 1200 nm. Exposure with a solid high-power infrared laser such as a laser or YAG laser is preferred.

  The lithographic printing plate precursor of the present invention on which an image has been recorded is then removed by removing the heat-sensitive layer in the non-image area by rubbing the plate surface with a rubbing member in the presence of the treatment liquid (if there is an overcoat layer, The overcoat layer is also removed at the same time.) In the non-image area, the surface of the hydrophilic support is exposed to produce a lithographic printing plate.

  Examples of the rubbing member usable in the present invention include non-woven fabric, cotton cloth, cotton pad, molton, rubber blade, brush and the like.

  As the treatment liquid used in the present invention, a hydrophilic treatment liquid is suitable. For example, water alone or an aqueous solution containing water as a main component is preferable, and in particular, the composition is the same as that of generally known dampening water. An aqueous solution containing an aqueous solution or a surfactant (anionic, nonionic, cationic, etc.) is preferred. Further, the treatment liquid of the present invention may contain an organic solvent. Examples of the solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, Xylene, etc.), halogenated hydrocarbons (trichlene, etc.), and the following polar solvents.

  Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol mono Ethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (ethyl acetate, methyl lactate, butyl lactate, propylene glycol monomethyl ether acetate, Diethylene glycol acetate, diethyl alcohol Rate, etc.), others (triethyl phosphate, tricresyl phosphate and the like).

  If the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. If the treatment liquid contains a solvent, it is safe and flammable. From this viewpoint, the concentration of the solvent is preferably less than 40% by mass. As the surfactant used in the treatment liquid of the present invention, a nonionic surfactant can be suitably used from the viewpoint of foam suppression.

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

  Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the treatment liquid of the present invention preferably has an HLB (Hydrophile-Lipophile Balance) value of 6 or more, and 8 or more. It is more preferable that Furthermore, the ratio of the nonionic surfactant contained in the treatment liquid is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass.

  In addition, an alkaline agent (for example, sodium carbonate, triethanolamine, diethanolamine, sodium hydroxide, silicates, etc.) or an acidic agent (for example, phosphoric acid, phosphorous acid, metaphosphoric acid, pyrophosphoric acid, oxalic acid) , Malic acid, tartaric acid, boric acid, amino acids, etc.), preservatives (for example, benzoic acid and its derivatives, sodium dehydroacetate, 3-isothiazolone compounds, 2-bromo-2-nitro-1,3-propanediol, 2 -Pyridinethiol-1-oxide sodium salt and the like) can also be used. Although the temperature of a process liquid can be used at arbitrary temperature, Preferably it is 10 to 50 degreeC.

  The removal of the heat-sensitive layer in the non-image area in the present invention can be preferably carried out by an automatic processor equipped with a processing liquid supply means and a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061, JP-A-60-59351, which performs rubbing while conveying an original plate for lithographic printing plate after image recording, Examples thereof include an automatic processor described in US Pat. No. 5,148,746, US Pat. No. 5,568,768, and the like, in which a lithographic printing plate precursor after image recording set on a cylinder is rubbed while rotating the cylinder. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable. As an example of an automatic processor suitable for the development processing of the present invention shown in FIG. 1, a processing liquid 10 is sent to a spray pipe 5 by a circulation pump 11 and showered, and a rotating brush roll 1 and a plate surface 12 (for lithographic printing plates) are used. An example of an automatic developing processing machine that is supplied to the original plate and rubs the plate surface 12 with the rotating brush roll 1 is illustrated. In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water and dried.

  The rotating brush roll that can be used can be selected as appropriate in consideration of the difficulty of scratching the image area and the stiffness of the support of the lithographic printing plate precursor. As the rotating brush roll, a known one formed by planting a brush material on a plastic or metal roll can be used. For example, a metal or plastic in which brush materials are implanted in rows, as described in Japanese Patent Application Laid-Open No. 58-159533, Japanese Patent Application Laid-Open No. 3-100534, or Japanese Utility Model Publication No. 62-167253. A brush roll in which the groove mold material is radially wound around a plastic or metal roll as a core without any gap can be used. The brush material includes plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylonitrile, poly (meth) acrylate, etc. Acrylic and polyolefin synthetic fibers such as polypropylene and polystyrene can be used. For example, the fiber has a hair diameter of 20 to 400 μm, and a hair length of 5 to 30 mm is preferable. Can be used. Furthermore, the outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec.

  The rotating direction of the rotating brush roll used in the present invention may be the same or opposite to the conveying direction of the lithographic printing plate precursor of the present invention. As described above, when two or more rotating brush rolls are used, it is preferable that at least one rotating brush roll rotates in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the heat sensitive layer in the non-image area. Furthermore, it is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

  The present invention will be described more specifically with reference to the following examples, but the scope of the present invention is of course not limited thereto.

[Example 1]
(Creation of aluminum support)
99.5% by mass aluminum, 0.01% by mass copper, 0.03% by mass titanium, 0.3% by mass iron, 0.1% by mass silicon, and a JIS A 1050 aluminum material (with a thermal conductivity of 0.1%). 48 cal / cm · sec · ° C.) using a 0.24 mm thick rolled plate, a 400 mesh Pamiston (made by Kyoritsu Ceramics) 20 mass% aqueous suspension and a rotating nylon brush (6,10-nylon) The surface was grained and washed thoroughly with water. This was immersed in a 15% by mass sodium hydroxide aqueous solution (containing 4.5% by mass of aluminum) and etched so that the dissolved amount of aluminum was 5 g / m ² , and then washed with running water. Further, neutralize with 1% by mass nitric acid, and then in a 0.7% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum), a rectangular wave with an anode voltage of 10.5 volts and a cathode voltage of 9.3 volts Using an alternating waveform voltage (current ratio r = 0.90, current waveform described in the example of JP-B-58-5796), electrolytic surface roughening treatment was performed at an anode time electricity of 160 clones / dm ^2. It was. After washing with water, it was immersed in a 10% by mass sodium hydroxide aqueous solution at 35 ° C., etched so that the amount of dissolved aluminum was 1 g / m ² , and then washed with water. Next, it was immersed in a 30% by mass sulfuric acid aqueous solution at 50 ° C., desmutted, and washed with water. Furthermore, the porous anodic oxide film formation process was performed using a direct current in 20 mass% sulfuric acid aqueous solution (containing 0.8 mass% aluminum) at 35 ° C. That is, electrolysis was performed at a current density of 13 A / dm ² , and the anodic oxide film mass was adjusted to 2.7 g / m ² by adjusting the electrolysis time. This support was washed with water, immersed in a 0.2 mass% aqueous solution of sodium silicate at 70 ° C. for 30 seconds, washed with water and dried.

(Synthesis of fine particle polymer 1)
Add 2.0 g of glycidyl methacrylate, 13.0 g of methyl methacrylate, and 200 ml of a polyoxyethylene phenol aqueous solution (concentration 9.8 × 10 ⁻³ mol / liter), and replace the system with nitrogen gas while stirring at 250 rpm. After the temperature of this liquid is 25 ° C., 10 ml of an aqueous cerium (IV) ammonium salt solution (concentration: 0.984 × 10 ⁻³ mol / liter) is added. At this time, an aqueous ammonium nitrate solution (concentration 58.8 × 10 ⁻³ mol / liter) is added to adjust the pH to 1.3 to 1.4. This was then stirred for 8 hours. The liquid thus obtained had a solid content concentration of 9.5% and an average particle size of 0.4 μm.

(Formation of heat-sensitive layer)
A coating liquid having the following composition was coated on the support and dried (90 ° C., 2 minutes) to form a thermosensitive layer having a dry coating mass of 1 g / m ² to obtain a lithographic printing plate precursor.

(Thermosensitive layer coating solution 1)
52.6 g of the dispersion of the fine particle polymer 1 synthesized as described above
Polyhydroxyethyl acrylate (Mass average molecular weight 25,000) 0.5g
Photothermal conversion agent A (below) 0.3g
100g of water

(Preparation of lithographic printing plate)
The lithographic printing plate precursor thus obtained was exposed under the conditions of a plate surface energy of 200 mJ / cm ² and a resolution of 2400 dpi using a Trendsetter 3244VFS manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser. Development processing was performed using an automatic processor having two rotating brush rolls of the mechanism. As the rotating brush roll, a brush roll having an outer diameter of 90 mm in which fibers made of polybutylene terephthalate (hair diameter: 200 μm, hair length: 17 mm) is used for the first brush roll, and the same direction as the conveying direction is used. Min. 200 revolutions (peripheral speed 0.94 m / sec at the tip of the brush), and the second brush roll was implanted with fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 17 mm) 60 mm outer diameter The brush roll was rotated 200 times per minute in the direction opposite to the conveying direction (peripheral speed of the brush tip: 0.63 m / sec). The planographic printing plate precursor was transported at a transport speed of 100 cm / min. The treatment liquid used was the following treatment liquid 1, showered from a spray pipe with a circulation pump, and supplied to the plate surface.

(Processing liquid 1)
RHEODOL TW-O106 0.5g
(Kao Co., Ltd., polyoxyethylene sorbitan monooleate, HLB = 10.0)
EU-3 (Etch solution manufactured by Fuji Photo Film Co., Ltd.) 2.0 g
97.5g of water

(Print evaluation)
Subsequently, the obtained lithographic printing plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg, and printing was performed (fountain solution used: IF-102 (Fuji Photo Film Co., Ltd.) was added at 4% by volume. Water, used ink: TK Hi-Echo SOYMZ ink (manufactured by Toyo Ink Co., Ltd.) and evaluated the number of non-image area inks to be printed at the time of printing. The smudges on the areas disappeared, and a printed matter with good ink fillability on the image areas was obtained.

[Comparative Example 1]
The lithographic printing plate precursor of Example 1 was subjected to development processing in the same manner as in Example 1 except that the rotating brush roll of the automatic processor in Example 1 was removed after image exposure in the same manner as in Example 1. That is, only the treatment liquid cleaning was performed without rubbing with a rubbing member. Thereafter, the obtained lithographic printing plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg, and printing was carried out in the same manner as in Example 1 to evaluate the number of non-image area inks to be removed during printing. 50 sheets were required until the non-image area was clean.

[Comparative Example 2]
The lithographic printing plate precursor of Example 1 was subjected to image exposure in the same manner as in Example 1 and then attached to the cylinder of a printing machine SOR-M manufactured by Heidelberg without any processing, and printing was performed in the same manner as in Example 1. As a result of evaluating the number of non-image area inks to be removed at the time of printing, 50 sheets were required until the non-image area was free of contamination.

[Example 2]
(Synthesis of fine particle polymer 2)
7.5 g of allyl methacrylate and 7.5 g of styrene were polymerized in the same manner as in the synthesis of the fine particle polymer 1. The liquid thus obtained had a solid content concentration of 9.5% and an average particle size of 0.4 μm.

(Formation of heat-sensitive layer)
A lithographic printing plate precursor was obtained by forming a heat sensitive layer in the same manner as in Example 1 except that the heat sensitive layer coating solution of Example 1 was changed to a coating solution having the following composition.

(Thermosensitive layer coating solution 2)
52.6 g of dispersion of the fine particle polymer 2 synthesized above
Polyacrylic acid (mass average molecular weight 25,000) 0.5g
Sorbitol triacrylate 1.0g
Photothermal conversion agent A 0.3g
100g of water

  Next, the obtained lithographic printing plate precursor was subjected to image exposure, development processing and printing in the same manner as in Example 1 and evaluated for the number of non-image area inks to be printed at the time of printing. Within the eyes, the non-image area was free from smudges, and a printed matter with good ink fillability in the image area was obtained.

Example 3
(Synthesis of fine particle polymer 3)
15 g of styrene was polymerized in the same manner as in the synthesis of the fine particle polymer 1. The liquid thus obtained had a solid content concentration of 9.0% and an average particle size of 0.3 μm.

(Formation of heat-sensitive layer)
A lithographic printing plate precursor was obtained by forming a heat sensitive layer in the same manner as in Example 1 except that the heat sensitive layer coating solution of Example 1 was changed to a coating solution having the following composition.

(Thermosensitive layer coating solution 3)
Dispersion of the above synthesized fine particle polymer 3 52.6 g
Polyacrylic acid (mass average molecular weight 25,000) 0.5g
Photothermal conversion agent A 0.3g
100g of water

  Next, the obtained lithographic printing plate precursor was subjected to image exposure, development processing and printing in the same manner as in Example 1 and evaluated for the number of non-image area inks to be printed at the time of printing. Within the eyes, the non-image area was free from smudges, and a printed matter with good ink fillability in the image area was obtained.

Example 4
A lithographic printing plate precursor was obtained in the same manner as in Example 1 except that the following overcoat layer was formed on the heat-sensitive layer.

(Formation of overcoat layer)
On the heat-sensitive layer, the following overcoat layer coating solution was applied and dried by heating (100 ° C., 2 minutes) to form an overcoat layer having a dry coating mass of 0.3 g / m ² .

(Overcoat layer coating solution)
・ 1g gum arabic
・ Emalex 710 0.025g
(Nippon Emulsion Co., Ltd., polyoxyethylene lauryl ether)
・ Water 19g

  Next, in the same manner as in Example 1, image exposure, development processing, and printing were carried out, and the number of non-image area inks to be removed at the time of printing was evaluated. As a result, there was no smudge, and a printed matter with good ink fillability in the image area was obtained.

FIG. 2 is a layout view showing a configuration of an automatic processor suitable for development processing of the lithographic printing plate preparation method of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating brush roll 2 Receiving roll 3 Conveying roll 4 Conveying guide plate 5 Spray pipe 6 Pipe line 7 Filter 8 Plate feed table 9 Discharge plate 10 Processing liquid (tank)
11 Circulating pump 12 Planographic printing plate precursor

Claims (9)

Before image recording on a lithographic printing plate precursor provided with a thermosensitive layer containing a hydrophilic resin, a photothermal conversion agent, and a fine particle polymer on a support having a hydrophilic surface, and before mounting on a printing press A method for producing a lithographic printing plate, comprising a step of rubbing a plate surface with a rubbing member in the presence of a processing solution by an automatic processor equipped with a rubbing member to remove a heat-sensitive layer in a non-image area. 2. The method for producing a lithographic printing plate according to claim 1, wherein the rubbing member is a rotating brush roll. 2. The hydrophilic resin has at least one of a hydroxyl group, a carboxyl group, a hydroxyethyl group, a hydroxypropyl group, an amino group, an aminoethyl group, an aminopropyl group, and a carboxymethyl group. 2. A method for producing a lithographic printing plate as described in 2. The method for producing a lithographic printing plate according to any one of claims 1 to 3, wherein the photothermal conversion agent is a cyanine dye. After performing image recording on a lithographic printing plate precursor provided with a heat-sensitive layer containing a cyanine dye containing a sulfonate group and a fine particle polymer on a support having a hydrophilic surface, before mounting on a printing press, A method for preparing a lithographic printing plate, comprising: a step of rubbing a plate surface with a rubbing member in the presence of a processing solution by an automatic processor equipped with a rubbing member to remove a heat-sensitive layer in a non-image area. 6. The method for producing a lithographic printing plate according to claim 5, wherein the rubbing member is a rotating brush roll.   The method for producing a lithographic printing plate according to claim 5 or 6, wherein the heat-sensitive layer contains a hydrophilic resin.   The fine particle polymer melts and coalesces by heat, and after performing image recording for fusing and coalescing the fine particle polymer by heat, it is placed in the presence of the treatment liquid by an automatic processor equipped with a rubbing member before mounting on the printing press. The method for producing a lithographic printing plate according to any one of claims 1 to 7, further comprising a step of rubbing the plate surface with a rubbing member to remove the heat-sensitive layer in the non-image area.   The method for preparing a lithographic printing plate according to claim 8, wherein the rubbing member is a rotating brush roll.

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