JP4911457B2 - Planographic printing plate preparation method and planographic printing plate precursor - Google Patents

Description

  The present invention relates to a method for preparing a lithographic printing plate and a lithographic printing plate precursor used in the method.

In general, a lithographic printing plate has a surface composed of an oleophilic image portion and a hydrophilic non-image portion. In lithographic printing, dampening water and oil-based ink are alternately applied to the plate surface, and the hydrophilic non-image area is dampened with a dampening water receiving area (ink non-receiving area) by utilizing the property that water and oil repel each other. ), After the ink is received only in the oleophilic image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive layer (image recording layer) is provided on a hydrophilic support has been widely used. Normally, after exposing a lithographic printing plate precursor through an original image such as a lithographic film, the photosensitive layer to be an image portion is left, and other unnecessary photosensitive layers are dissolved with an alkaline developer or an organic solvent. The lithographic printing plate is obtained by carrying out plate making by a method of exposing the surface of the hydrophilic support to form a non-image portion by removing it.

  In the conventional plate-making process of a lithographic printing plate precursor, a step of dissolving and removing unnecessary photosensitive layers with a developer or the like is necessary after exposure, but simplifies such additional wet processing. Is listed as one of the issues. As one of simplification, it is desired that development can be performed with an aqueous solution close to neutrality or simple water.

  On the other hand, in recent years, digitization technology that electronically processes, stores, and outputs image information using a computer has become widespread, and various new image output methods corresponding to such digitization technology have been put into practical use. It has come to be. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate technology for manufacturing is attracting attention. Accordingly, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

  From the background as described above, it is now more strongly desired than ever to adapt both the simplification of the plate making operation and the digitization.

  On the other hand, for example, in Patent Document 1, in an image forming layer of a lithographic printing plate precursor having an image forming layer containing a hydrophobizing precursor, a hydrophilic resin, and a photothermal conversion agent on a hydrophilic support. In addition to the on-press development, it can also be used for printing after exposure by liquid development using water or a suitable aqueous solution as a developer by further containing a compound having an ethylene oxide chain. Has been.

Patent Document 2 contains (i) a hydrophilic support, and (ii) a radical polymerizable ethylenically unsaturated monomer, a radical polymerization initiator and an infrared absorbing dye, and is cured by infrared laser exposure. Moreover, a lithographic printing plate precursor comprising an oleophilic heat-sensitive layer containing 60% by mass or more of water and developable with an aqueous developer having a pH of 2.0 to 10.0 is prepared and exposed imagewise with an infrared laser. A processing method for a lithographic printing plate precursor comprising removing an uncured region of the heat-sensitive layer with an aqueous developer is described.
JP 2002-365789 A US Patent Application Publication No. 2004/0013968

However, in order to be able to develop with an aqueous developer having a pH of 2.0 to 10.0, the photosensitive layer needs to be hydrophilic or highly water-permeable. The compatibility of the water resistance and film strength of the photosensitive layer is a problem.
As a means to overcome this problem, it is conceivable to increase the sensitivity, that is, to improve the water resistance discrimination between the unexposed part and the exposed part in a reaction system with high curing efficiency. It is also desirable that fog does not occur when handled under safelight.
The present invention meets such a demand, and an object of the present invention is to provide a plate making method capable of developing with an aqueous developer having a pH of 2.0 to 10.0 and providing a good printing plate, and this method. It is intended to provide a lithographic printing plate precursor having high sensitivity and excellent safelight suitability used in the above.

The present inventor has found that the above problem can be solved by the following configuration.
<1> On a hydrophilic support, (A) a sensitizing dye having an absorption maximum at 350 to 450 nm represented by the following general formula (I) or (II), (B) a polymerization initiator, (C) polymerization (D) a photosensitive layer containing a hydrophobic binder polymer having a solubility in water at 25 ° C. and an aqueous solution having a pH of 10 or more of 0.5% by mass or less and an acid value of 0.3 meq / g or less, a protective layer, In this order, the lithographic printing plate precursor is subjected to laser exposure at 350 to 450 nm, and then the plate surface is rubbed with a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic processor equipped with a rubbing member. A method for preparing a lithographic printing plate, comprising removing a protective layer and a photosensitive layer in an unexposed area.


R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
R ¹⁵ to R ³² each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a cyano group or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.
<2> (D) The method for preparing a lithographic printing plate as described in <1> above, wherein the hydrophobic binder polymer is a (meth) acrylic resin or a polyurethane resin.
<3> (B) The method for preparing a lithographic printing plate as described in <1> or <2> above, wherein the polymerization initiator is a hexaarylbiimidazole compound.
<4> The method for preparing a lithographic printing plate as described in <3> above, wherein the photosensitive layer further contains (E) a chain transfer agent.
<5> (E) The method for preparing a lithographic printing plate according to <4>, wherein the chain transfer agent is a thiol compound represented by the following general formula.

Here, R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A represents a 5-membered or 6-membered ring having a carbon atom together with an N = CN moiety. The atomic group which forms the heterocyclic ring of A, and A may further have a substituent.
<6> (D) The hydrophobic binder polymer is at least one selected from the group consisting of a (meth) acrylic copolymer having a crosslinkable group in the side chain and a polyurethane resin having a crosslinkable group in the side chain. The method for producing a lithographic printing plate as described in any one of <1> to <5> above, wherein:
<7> The method for producing a lithographic printing plate as described in any one of <1> to 6 above, wherein a part or all of the photosensitive layer component is encapsulated in a microcapsule.
<8> The method for producing a lithographic printing plate as described in any one of <1> to <7>, wherein the rubbing member is at least two rotating brush rolls.
<9> The method for preparing a lithographic printing plate as described in any one of <1> to <8> above, wherein the pH of the developer is from 3 to 8.
<10> The method for preparing a lithographic printing plate as described in any one of <1> to <9> above, wherein the exposed lithographic printing plate precursor is further subjected to heat treatment between exposure and development.
<11> On a hydrophilic support, (A) a sensitizing dye having an absorption maximum at 350 to 450 nm represented by the following general formula (I) or (II), (B) a polymerization initiator, (C) polymerization (D) a photosensitive layer containing a hydrophobic binder polymer having a solubility in water at 25 ° C. and an aqueous solution having a pH of 10 or more of 0.5% by mass or less and an acid value of 0.3 meq / g or less, a protective layer, In this order, the lithographic printing plate precursor is exposed to a laser beam of 350 to 450 nm, and then the plate surface is rubbed with a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic processor equipped with a rubbing member. A lithographic printing plate precursor capable of removing the protective layer and the non-exposed photosensitive layer.


R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
R ¹⁵ to R ³² each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a cyano group or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.
<12> The lithographic printing plate precursor as described in <11> above, wherein the (D) hydrophobic binder polymer is a (meth) acrylic resin or a polyurethane resin.
<13> (D) The hydrophobic binder polymer is at least one selected from the group consisting of a (meth) acrylic copolymer having a crosslinkable group in the side chain and a polyurethane resin having a crosslinkable group in the side chain. The lithographic printing plate precursor as described in <11> above, wherein
<14> The lithographic printing plate precursor as described in any one of <11> to <13> above, wherein the polymerization initiator (B) is a hexaarylbiimidazole compound.
<15> The lithographic printing plate precursor as described in <14> above, wherein the photosensitive layer further comprises (E) a chain transfer agent.
<16> (E) The lithographic printing plate precursor as described in <15> above, wherein the chain transfer agent is a thiol compound represented by the following general formula.

Here, R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A represents a 5-membered or 6-membered ring having a carbon atom together with an N = CN moiety. The atomic group which forms the heterocyclic ring of A, and A may further have a substituent.
<17> The lithographic printing plate precursor as described in any one of <11> to <16> above, wherein the exposed lithographic printing plate precursor is further subjected to heat treatment between exposure and development.
<18> The lithographic printing plate as described in any one of <1> to <10> above, wherein the developer contains a surfactant represented by the following general formula (III) or (IV): Manufacturing method.

(Wherein R _{1 to} R ₁₀ each represent a hydrogen atom or an alkyl group, l represents an integer of 1 to 3, and X ₁ and X ₂ represent a sulfonate, a monoester sulfate, a carboxylate or a phosphate, respectively. And the total number of carbon atoms in R _{1 to} R ₅ or R _{6 to} R ₁₀ is 3 or more.)
<19> The lithographic printing plate as described in any one of <1> to <10> above, wherein the developer contains a surfactant represented by the following general formula (V) or (VI): Manufacturing method.

(Wherein R _{1 to} R ₁₀ each represent a hydrogen atom or an alkyl group, l represents an integer of 1 to 3, and X ₁ and X ₂ represent a sulfonate, a monoester sulfate, a carboxylate or a phosphate, respectively. , Y ₁ and Y ₂ are —C _n H _2n —, —C _nm H _{2 (nm)} OC _m H _2m —, —O— (CH ₂ CH ₂ O) _n —, —O— ( _{CH 2 CH 2 CH 2 O)} n - or represents -CO-NH-, is n ≧ 1, n ≧ m ≧ 0, R 1 ~R 5 and _{Y 1} or _R 6 _{to R 10} and _{Y 2} in the (The total number of carbon atoms is 3 or more.)
<20> The lithographic plate according to any one of <1> to <10>, wherein the developer contains a surfactant represented by any of the following general formulas (VII) to (IX): A method for preparing a printing plate.

(In the formula (VII), Ra represents a hydrogen atom or an alkyl group, and A and B are independently a group containing an ethylene oxide group, a carboxylic acid group, or a carboxylate.
In formula (VIII), Rb and Rc independently represent a hydrogen atom or an alkyl group, C is a group containing an alkyl group or an ethylene oxide group, and D is a group containing a carboxylate anion.
In formula (IX), Rd, Re, Rf and Rg each represent a hydrogen atom or an alkyl group, and Z ⁻ is a counter anion. )
Although this invention has the structure as described in said <1>-<20>, it is described below also including another matter.
(1) On a hydrophilic support, (A) a sensitizing dye having an absorption maximum at 350 to 450 nm represented by the following general formula (I) or (II), (B) a polymerization initiator, (C) polymerization A lithographic printing plate precursor having a functional compound, (D) a photosensitive layer containing a hydrophobic binder polymer having an acid value of 0.3 meq / g or less, and a protective layer in this order, after being exposed to laser at 350 to 450 nm, and then a rubbing member A lithographic printing plate characterized by removing the protective layer and the non-exposed portion of the photosensitive layer by rubbing the plate surface with a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic processor equipped with Manufacturing method.

R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
R ¹⁵ to R ³² each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a cyano group or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.

(2) The method for preparing a lithographic printing plate as described in (1) above, wherein the polymerization initiator (B) is a hexaarylbiimidazole compound.

(3) The method for preparing a lithographic printing plate as described in (2) above, wherein the photosensitive layer further contains (E) a chain transfer agent.

(4) The method for preparing a lithographic printing plate as described in (3) above, wherein the chain transfer agent (E) is a thiol compound represented by the following general formula (T).

  Here, R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A represents a 5-membered or 6-membered ring having a carbon atom together with an N = CN moiety. The atomic group which forms the heterocyclic ring of A, and A may further have a substituent.

(5) (D) The hydrophobic binder polymer is at least one selected from the group consisting of a (meth) acrylic copolymer having a crosslinkable group in the side chain and a polyurethane resin having a crosslinkable group in the side chain. The method for producing a lithographic printing plate as described in any one of (1) to (4) above, wherein:

(6) The method for preparing a lithographic printing plate as described in any one of (1) to (5) above, wherein some or all of the photosensitive layer components are encapsulated in microcapsules.

(7) The method for preparing a lithographic printing plate as described in any one of (1) to (6) above, wherein the rubbing member is at least two rotating brush rolls.

(8) The method for preparing a lithographic printing plate as described in any one of (1) to (7) above, wherein the pH of the developer is from 3 to 8.
(9) The method for preparing a lithographic printing plate as described in any one of (1) to (8) above, wherein the exposed lithographic printing plate precursor is further subjected to heat treatment between exposure and development.

(10) On a hydrophilic support, (A) a sensitizing dye having an absorption maximum at 350 to 450 nm represented by the general formula (I) or (II), (B) a polymerization initiator, and (C) polymerization. (D) a lithographic printing plate precursor having a photosensitive layer containing a hydrophobic binder polymer having an acid value of 0.3 meq / g or less, and a protective layer in this order, after laser exposure at 350 to 450 nm, A lithographic printing plate precursor capable of removing a protective layer and a photosensitive layer in an unexposed area by rubbing the plate surface with a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic processor equipped with a rubbing member.

(11) The lithographic printing plate precursor as described in (10) above, wherein the polymerization initiator (B) is a hexaarylbiimidazole compound.
(12) The lithographic printing plate precursor as described in (11) above, wherein the photosensitive layer further contains (E) a chain transfer agent.
(13) The lithographic printing plate precursor as described in (12) above, wherein the chain transfer agent (E) is a thiol compound represented by the general formula (T).
(14) The lithographic printing plate precursor as described in any one of (10) to (13) above, wherein the exposed lithographic printing plate precursor is further subjected to heat treatment between exposure and development.

(15) The lithographic printing plate as described in any one of (1) to (9) above, wherein the developer contains a surfactant represented by the following general formula (III) or (IV): Manufacturing method.

(Wherein R _{1 to} R ₁₀ each represent a hydrogen atom or an alkyl group, l represents an integer of 1 to 3, and X ₁ and X ₂ represent a sulfonate, a monoester sulfate, a carboxylate or a phosphate, respectively. And the total number of carbon atoms in R _{1 to} R ₅ or R _{6 to} R ₁₀ is 3 or more.)

(16) The lithographic printing plate as described in any one of (1) to (9) above, wherein the developer contains a surfactant represented by the following general formula (V) or (VI): Manufacturing method.

(Wherein R _{1 to} R ₁₀ each represent a hydrogen atom or an alkyl group, l represents an integer of 1 to 3, and X ₁ and X ₂ represent a sulfonate, a monoester sulfate, a carboxylate or a phosphate, respectively. , Y ₁ and Y ₂ are —C _n H _2n —, —C _nm H _{2 (nm)} OC _m H _2m —, —O— (CH ₂ CH ₂ O) _n —, —O— ( CH ₂ CH ₂ CH ₂ O) _n — or —CO—NH—, where n ≧ 1, n ≧ m ≧ 0, in R _{1 to} R ₅ or R _{6 to} R ₁₀ and in Y ₁ or Y ₂ The total number of carbon atoms is 3 or more.)

(17) The lithographic plate as described in any one of (1) to (9) above, wherein the developer contains a surfactant represented by any of the following general formulas (VII) to (IX) A method for preparing a printing plate.

(In the formula (VII), Ra represents a hydrogen atom or an alkyl group, and A and B are independently a group containing an ethylene oxide group, a carboxylic acid group, or a carboxylate.
In formula (VIII), Rb and Rc independently represent a hydrogen atom or an alkyl group, C is a group containing an alkyl group or an ethylene oxide group, and D is a group containing a carboxylate anion.
In formula (IX), Rd, Re, Rf and Rg each represent a hydrogen atom or an alkyl group, and Z ⁻ is a counter anion. )

  According to the present invention, there is provided a plate making method in which a lithographic printing plate precursor having high sensitivity and good safelight suitability is developed with an aqueous developer having a pH of 2.0 to 10.0 to produce a good printing plate. it can.

[Lithographic printing plate precursor]
First, the planographic printing plate precursor used in the present invention will be described.

<Photosensitive layer>
The photosensitive layer of the present invention comprises (A) a sensitizing dye having an absorption maximum at 350 to 450 nm represented by the general formula (I) or (II), (B) a polymerization initiator, (C) a polymerizable compound, ( D) A hydrophobic binder polymer having an acid value of 0.3 meq / g or less is contained.

According to the above aspect, a lithographic printing plate precursor having high sensitivity and excellent safelight suitability can be obtained by laser exposure at 350 to 450 nm.
The photosensitive layer can further contain other components as required. Hereinafter, the components of the photosensitive layer will be described in detail.

(A) Sensitizing dye The sensitizing dye having the maximum absorption in the wavelength region of 350 to 450 nm contained in the photosensitive layer of the present invention is a compound represented by the following general formula (I) or (II).

R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
R ¹⁵ to R ³² each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a cyano group or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.
The alkyl group and the alkoxy group may have a substituent and may be linear or branched, but is preferably branched. Examples of the substituent include a halogen atom and a hydroxyl group.
Further, the alkylene chain in the alkyl group and alkoxy group may contain an ester bond, an ether bond, or a thioether bond.

R ¹ , R ⁵ , R ⁶ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are preferably each independently a hydrogen atom, a fluorine atom or a chlorine atom, particularly R ¹ , R ⁵ , R ⁶ and R ¹⁰ are preferably a hydrogen atom, R ^{2 to} R ⁴ and R ^{7 to} R ⁹ are independently an alkoxy group, and at least two are preferably branched alkoxy groups having 3 to 15 carbon atoms.
R ^2, R ⁴ , R ⁷ and R ⁹ are particularly preferably a methoxy group, and R ³ and R ⁸ are each a branched alkoxy group having 3 to 15 carbon atoms.

R ¹⁵ , R ¹⁹ , R ²⁰ , R ²⁴ and R ^{25 to} R ³² are preferably each independently a hydrogen atom, a fluorine atom or a chlorine atom, and in particular, R ¹⁵ , R ¹⁹ , R ²⁰ and R ²⁴ are It is preferable that a hydrogen atom, R < ¹⁶ > -R < ¹⁸ >, R < ²¹ > -R < ²³ > is an alkoxy group independently, and at least 2 is a C3-C15 branched alkoxy group.
R ¹⁶ , R ¹⁸ , R ²¹ and R ²³ are particularly preferably a methoxy group, and R ¹⁷ and R ²² are each a branched alkoxy group having 3 to 15 carbon atoms.

  The sensitizing dye can be synthesized by a known method such as the method described in WO2005 / 029187.

Details of the usage such as which structure of these sensitizing dyes are used, whether they are used alone or in combination of two or more, and how much is added, can be appropriately set according to the performance design of the final photosensitive material. .
For example, the compatibility in the composition constituting the photosensitive layer can be increased by using two or more sensitizing dyes in combination. In selecting the sensitizing dye, in addition to the photosensitivity, the molar extinction coefficient at the emission wavelength of the light source used is an important factor. By using a dye having a large molar extinction coefficient, the amount of the dye added can be made relatively small, which is economical and advantageous when used for a lithographic printing plate precursor in terms of film physical properties of the photosensitive layer. is there. The photosensitivity of the photosensitive layer, the resolution, and the physical properties of the exposed film are greatly affected by the absorbance at the light source wavelength. Therefore, the addition amount of the sensitizing dye is appropriately selected in consideration of these.

  However, for example, for the purpose of curing a thick film having a thickness of 5 μm or more, the degree of curing may be increased by lower absorbance. When used as a lithographic printing plate used in a relatively thin film thickness, the addition amount of the sensitizing dye is such that the absorbance of the photosensitive layer of the present invention is in the range of 0.1 to 1.5, preferably 0.25 to 1. It is preferable to set so as to be in the range. Usually, the amount is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and most preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the photosensitive layer.

(B) Polymerization initiator As a polymerization initiator used in the present invention, a trihalomethyl compound, a carbonyl compound, an organic peroxide, an azo compound, an azide compound, a metallocene compound, a hexaarylbiimidazole compound, an organic boron compound, Examples include disulfone compounds, oxime ester compounds, and onium salt compounds. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds, and metallocene compounds is preferable, and hexaarylbiimidazole compounds are particularly preferable. Two or more of the above polymerization initiators can be used in combination as appropriate.

  Examples of the hexaarylbiimidazole polymerization initiator include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p-dichlorophenyl) ) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2 , 2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5 ′ − Traphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.

  The trihalomethyl compound is preferably trihalomethyl-s-triazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methoxy-4,6-bis (trichloromethyl) -s-triazine, 2- Trimethyl compounds described in JP-A-58-29803 such as amino-4,6-bis (trichloromethyl) -s-triazine, 2- (P-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine and the like. Examples thereof include s-triazine derivatives having a halogen-substituted methyl group.

  Examples of the onium salt include onium salts represented by the following general formula (III).

In general formula (III), R ¹¹ , R ¹² and R ¹³ may be the same or different,
A hydrocarbon group having 20 or less carbon atoms which may have a substituent is shown. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms.
Z ⁻ represents a counter ion selected from the group consisting of halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, carboxylate ion, and sulfonate ion, preferably perchlorate ion, hexa Fluorophosphate ions, carboxylate ions, and aryl sulfonate ions.

As the titanocene compound, for example, known compounds described in JP-A Nos. 59-152396 and 61-151197 can be appropriately selected and used.
Specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5, 6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2, 4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4-difluoro Phen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2, 3, 5, 6 Tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis [2,6-difluoro-3- ( Pyr-1-yl) phenyl] titanium and the like.

Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′
-(Methylthio) phenyl) -2-morpholino-1-propanone, acetophenone derivatives such as 1,1,1-trichloromethyl- (p-butylphenyl) ketone, thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2- Thioxanthone derivatives such as chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate, ethyl p-diethylaminobenzoate, etc. Can be mentioned.

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A 2000-66385. And compounds described in JP 2000-80068 A.

The polymerization initiator in the present invention is suitably used alone or in combination of two or more.
The amount of the polymerization initiator used in the photosensitive layer in the present invention is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the photosensitive layer. More preferably, it is 1.0 mass%-10 mass%.

(C) Polymerizable compound The polymerizable compound used in the photosensitive layer in the invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and preferably has at least one terminal ethylenically unsaturated bond, preferably It is selected from compounds having two or more. 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, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

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

  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-51-47334 and JP-A-57-196231, JP-A-59-5240, JP-A-59- Those having an aromatic skeleton described in JP-A No. 5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

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

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (A)
(However, R ₄ and R ₅ represent H or CH _3. )

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable. Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

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

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable. A method of adjusting both sensitivity and strength by using a compound) is also effective.
In addition, the compatibility and dispersibility with other components in the photosensitive layer (for example, binder polymer, polymerization initiator, colorant, etc.), the selection and use method of the polymerizable compound is an important factor. In some cases, the compatibility can be improved by using a low-purity compound or by using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving adhesion to a support or a protective layer described later.

  The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass, based on the total solid content of the photosensitive layer. These may be used alone or in combination of two or more. In addition, the usage of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer construction and coating method such as undercoating and overcoating can also be carried out.

(D) Hydrophobic binder polymer As the hydrophobic binder polymer that can be used in the photosensitive layer of the invention, a water-insoluble polymer is preferably used. Furthermore, the hydrophobic binder polymer that can be used in the present invention preferably contains substantially no acid group such as a carboxyl group, a sulfone group, and a phosphoric acid group. The acid value of the binder polymer (the acid content per gram of polymer) In terms of the number of chemical equivalents) is preferably 0.3 meq / g or less, and more preferably 0.1 meq / g or less. Within this range, the film strength, water resistance and fillability of the photosensitive layer are improved, and printing durability is improved.
That is, the hydrophobic binder polymer that can be used in the present invention is preferably insoluble in water and an aqueous solution of pH 10 or higher, and the solubility of the hydrophobic binder polymer in water and an aqueous solution of pH 10 or higher (polymer concentration at the time of saturated dissolution). However, it is preferable that it is 0.5 mass% or less, More preferably, it is 0.1 mass% or less. The solubility measuring temperature is a temperature during plate-making development, and is 25 ° C. here.

As the hydrophobic binder polymer, as long as the performance of the lithographic printing plate of the present invention is not impaired, a conventionally known one can be used without limitation within the above range, and a linear organic polymer having a film property is preferable.
As an example of such a hydrophobic binder polymer, a polymer selected from acrylic resin, polyvinyl acetal resin, polyurethane resin, polyamide resin, epoxy resin, methacrylic resin, styrene resin, and polyester resin is preferable. Especially, an acrylic resin is preferable and a (meth) acrylic acid ester copolymer is preferable. More specifically, an alkyl (meth) acrylate or an aralkyl ester and an ester residue (—COOR) of (meth) acrylate ester may have —CH ₂ CH ₂ O— unit or —CH ₂ CH ₂ NH— unit as R. A copolymer with a (meth) acrylic acid ester containing is particularly preferred. The preferable alkyl group of the said (meth) acrylic-acid alkylester is a C1-C5 alkyl group, and a methyl group is more preferable. Preferable (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.

Furthermore, the hydrophobic binder polymer can be provided with a crosslinking property in order to improve the film strength of the image area.
In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.

Here, the crosslinkable group is a group that crosslinks the polymer binder in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, an onium salt structure etc. are mentioned, for example. Especially, an ethylenically unsaturated bond group is preferable and the functional group represented by the following general formula (1)-(3) is especially preferable.

In the general formula (1), R ^{1 to} R ³ each independently represents a hydrogen atom or a monovalent organic group, and R ¹ is preferably a hydrogen atom or an alkyl which may have a substituent. A hydrogen atom or a methyl group is preferable because of high radical reactivity. R ² and R ³ are each independently a hydrogen atom, a halogen atom, an amino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an optionally substituted alkyl group, or a substituted group. An aryl group that may have a group, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

X represents an oxygen atom, a sulfur atom, or N (R ¹² ) —, and R ¹² represents a hydrogen atom or a monovalent organic group. Here, examples of R ¹² include an alkyl group which may have a substituent. Among them, a hydrogen atom, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.

  Here, examples of the substituent that can be introduced include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, an amino group, an alkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, A sulfo group, a nitro group, a cyano group, an amide group, an alkylsulfonyl group, an arylsulfonyl group and the like can be mentioned.

In the general formula (2), R ^{4 to} R ⁸ each independently represents a hydrogen atom or a monovalent organic group, and R ^{4 to} R ⁸ are preferably a hydrogen atom, a halogen atom, an amino group, or a dialkyl. Amino group, carboxyl group, alkoxycarbonyl group, sulfo group, nitro group, cyano group, alkyl group which may have a substituent, aryl group which may have a substituent, alkoxy which may have a substituent A group, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, An arylsulfonyl group which may have a substituent, etc. are mentioned, among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent,
An aryl group which may have a substituent is preferable.

Examples of the substituent that can be introduced are the same as those in the general formula (1). Y represents an oxygen atom, a sulfur atom, or N (R ¹² ) —. R ¹² has the same meaning as R ¹² in general formula (1), and preferred examples are also the same.

In the general formula (3), R ⁹ preferably includes a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom or a methyl group has high radical reactivity. preferable. R ¹⁰ and R ¹¹ are each independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or an alkyl group which may have a substituent. An aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, a substituent An arylamino group that may have, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, and the like, among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

Here, examples of the substituent that can be introduced are the same as those in the general formula (1). Further, Z is an oxygen atom, a sulfur atom, -N (R ¹³⁾ -, or a phenylene group which may have a substituent. Examples of R ¹³ include an alkyl group which may have a substituent. Among them, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.
Among these, (meth) acrylic acid copolymers having a crosslinkable group in the side chain and polyurethane are more preferable.

  Hydrophobic binder polymers having crosslinkability include, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) added to the crosslinkable functional group, and polymerization of polymerizable compounds directly between polymers. Addition polymerization through a chain forms a cross-link between polymer molecules and cures. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

  The content of the crosslinkable group in the hydrophobic binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1 g per 1 g of the hydrophobic binder polymer. Is 1.0 to 7.0 mmol, most preferably 2.0 to 5.5 mmol.

Further, it is preferable that the binder polymer is hydrophilic from the viewpoint of improving developability with respect to an aqueous solution, and it is important that the binder polymer is compatible with the polymerizable compound contained in the photosensitive layer from the viewpoint of improving printing durability. Yes, ie lipophilic. From such a viewpoint, in the present invention, it is also effective to copolymerize a hydrophilic group and a lipophilic group in a hydrophobic binder polymer in order to improve developability and printing durability. Examples of the hydrophilic group include a hydroxy group, a carboxylate group, a hydroxyethyl group, an ethyleneoxy group,
Preferred examples include those having a hydrophilic group such as hydroxypropyl group, polyoxyethyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, amide group, carboxymethyl group.

The hydrophobic binder polymer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. Is more preferable. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The hydrophobic binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

The hydrophobic binder polymer may be used alone or in combination of two or more.
The content of the hydrophobic binder polymer is generally 5 to 90% by mass and 10 to 70% by mass with respect to the total solid content of the photosensitive layer in terms of good image area strength and image forming property. It is preferable that it is 10-60 mass%.

(E) Chain transfer agent The photosensitive layer of the invention preferably contains a chain transfer agent. Chain transfer agents contribute to improved sensitivity and storage stability. As the compound that acts as a chain transfer agent, for example, a compound group having SH, PH, SiH, and GeH in the molecule is used. These can generate hydrogen by donating hydrogen to a low-activity radical species to generate a radical, or after being oxidized and deprotonated.

In the photosensitive layer of the present invention, in particular, a thiol compound (for example, 2-mercaptobenzimidazoles) can be preferably used as a chain transfer agent.
Especially, the thiol compound represented by the following general formula (T) is used especially suitably. By using this thiol compound as a chain transfer agent, the problem of odor and sensitivity reduction due to evaporation from the photosensitive layer and diffusion to other layers are avoided, and it has excellent storage stability and high sensitivity and high printing durability. A lithographic printing plate precursor is obtained.

  In general formula (T), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent, and A represents a 5-membered ring having a carbon atom together with an N = CN moiety. Alternatively, it represents an atomic group that forms a 6-membered heterocycle, and A may further have a substituent.

  More preferably, those represented by the following general formula (T-1) or general formula (T-2) are used.

  In general formulas (T-1) and (T-2), R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and X represents a halogen atom or an alkoxyl group. Represents an alkyl group which may have a substituent, or an aryl group which may have a substituent.

  Specific examples of the compound represented by the general formula (T) are shown below, but the present invention is not limited thereto.

  The amount of these chain transfer agents (thiol compounds) used is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the photosensitive layer. More preferably, it is 1.0-10 mass%.

(F) Co-sensitizer In the present invention, a co-sensitizer can be used. The co-sensitizer is an additive that can further improve the sensitivity of the photosensitive layer when added to the photosensitive layer. The mechanism of action is not clear, but many are thought to be based on the following chemical process. That is, a photoreaction initiated by light absorption of the above-described photopolymerization initiation system, and various intermediate active species (radicals, peroxides, oxidizing agents, reducing agents, etc.) generated in the course of the subsequent addition polymerization reaction, It is presumed that the co-sensitizer reacts to generate a new active radical. The co-sensitizers are roughly classified into (a) those that can be reduced to generate active radicals, (b) those that can be oxidized to generate active radicals, and (c) more active by reacting with less active radicals. However, there are many cases where there is no general rule as to which individual compounds belong to them.

(A) Compound that is reduced to produce an active radical Compound having a carbon-halogen bond: It is considered that the carbon-halogen bond is reductively cleaved to generate an active radical. Specifically, for example, trihalomethyl-s-triazines and trihalomethyloxadiazoles can be preferably used.
Compound having nitrogen-nitrogen bond: It is considered that the nitrogen-nitrogen bond is reductively cleaved to generate an active radical. Specifically, hexaarylbiimidazoles and the like are preferably used.
Compound having oxygen-oxygen bond: It is considered that the oxygen-oxygen bond is reductively cleaved to generate an active radical. Specifically, for example, organic peroxides are preferably used.
Onium compounds: It is considered that carbon-hetero bonds and oxygen-nitrogen bonds are reductively cleaved to generate active radicals. Specifically, for example, diaryliodonium salts, triarylsulfonium salts, N-alkoxypyridinium (azinium) salts and the like are preferably used.

(B) Compound which is oxidized to generate an active radical Alkylate complex: It is considered that a carbon-hetero bond is oxidatively cleaved to generate an active radical. Specifically, for example, triarylalkyl borates are preferably used.
Alkylamine compound: It is considered that the C—X bond on carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, a benzyl group or the like. Specific examples include ethanolamines, N-phenylglycines, N-trimethylsilylmethylanilines, and the like.
Sulfur-containing and tin-containing compounds: Compounds in which the nitrogen atoms of the above-described amines are replaced with sulfur atoms and tin atoms can generate active radicals by the same action. Further, a compound having an SS bond is also known to be sensitized by SS cleavage.
α-Substituted methylcarbonyl compound: An active radical can be generated by oxidative cleavage of the carbonyl-α carbon bond. Moreover, what converted carbonyl into the oxime ether also shows the same effect | action. Specifically, 2-alkyl-1- [4- (alkylthio) phenyl] -2-morpholinopropanone-1 and these and hydroxyamines were reacted, and then N-OH was etherified. Examples include oxime ethers and N-OH esterified oxime esters.
Sulfinic acid salts: An active radical can be reductively generated. Specific examples include sodium arylsulfinate.

(C) Compounds that react with radicals to convert to highly active radicals or act as chain transfer agents Compounds that react with radicals to convert to highly active radicals or act as chain transfer agents include, for example, SH, PH in the molecule , SiH, and GeH are used. These can generate hydrogen by donating hydrogen to a low-activity radical species to generate radicals, or after being oxidized and deprotonated. Specifically, 2-mercaptobenzimidazoles etc. are mentioned, for example.

More specific examples of these co-sensitizers include compounds described as additives for the purpose of improving sensitivity in JP-A-9-236913.
Some examples are shown below, but the present invention is not limited thereto.

  These co-sensitizers can also be subjected to various chemical modifications for improving the characteristics of the photosensitive layer of the lithographic printing plate precursor as in the case of the sensitizing dye. For example, bonding with sensitizing dyes, polymerization initiators, addition polymerizable unsaturated compounds and other radical generating parts, introduction of hydrophilic sites, compatibility improvement, introduction of substituents for suppressing crystal precipitation, and improved adhesion Methods such as introduction of substituents and polymerization can be used. These co-sensitizers can be used alone or in combination of two or more. The amount used is 0.05 to 100 parts by mass, preferably 1 to 80 parts by mass, and more preferably 3 to 50 parts by mass with respect to 100 parts by mass of the compound having an ethylenically unsaturated double bond.

<Microcapsule>
In the present invention, as a method for incorporating the above-mentioned photosensitive layer constituents and other constituents described later into the photosensitive layer, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, the constituents are described. Part or all of the components can be encapsulated in microcapsules and added to the photosensitive layer. In that case, each component can be contained in any ratio in and out of the microcapsule.

As a method for microencapsulating the photosensitive layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, it is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into said water-insoluble polymer.

  The average particle size of the microcapsules is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

<Other photosensitive layer components>
The photosensitive layer of the present invention can further contain various additives as required. These will be described below.

<Surfactant>
In the present invention, it is preferable to use a surfactant in the photosensitive layer in order to promote developability and improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

The anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.
The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Also preferred are the fluorosurfactants described in JP-A-62-170950, JP-A-62-226143 and JP-A-60-168144.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 7% by mass with respect to the total solid content of the photosensitive layer.

<Hydrophilic polymer>
In the present invention, a hydrophilic polymer can be contained in order to improve the developability and the microcapsule dispersion stability.
Examples of the hydrophilic polymer include hydroxy group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, Preferred examples include those having a hydrophilic group such as an amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group.

Specific examples 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 their salts, 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, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

The hydrophilic polymer preferably has a mass average molecular weight of 5000 or more, more preferably 10,000 to 300,000. The hydrophilic polymer may be any of a random polymer, a block polymer, a graft polymer, and the like.
The content of the hydrophilic polymer in the photosensitive layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

<Colorant>
In the present invention, a dye having a large absorption in the visible light region can be used as an image colorant. 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 Japanese Patent No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is preferably 0.01 to 10% by mass with respect to the total solid content of the image recording material.

<Bakeout agent>
In the photosensitive layer of the present invention, a compound that changes color by an acid or a radical can be added in order to produce a printout image. As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

  Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Kogyo Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by acid or radical is 0.01 to 15% by mass relative to the solid content of the photosensitive layer.

<Polymerization inhibitor>
In order to prevent unnecessary thermal polymerization of the radical polymerizable compound during the production or storage of the photosensitive layer, it is preferable to add a small amount of a thermal polymerization inhibitor to the photosensitive layer of the present invention.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t- (Butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the photosensitive layer.

<Higher fatty acid derivatives, etc.>
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenamide is added to the photosensitive layer of the present invention so that it is unevenly distributed on the surface of the photosensitive layer during the drying process after coating. May be. The amount of the higher fatty acid derivative added is about 0.1 to about 1 with respect to the total solid content of the photosensitive layer.
It is preferably 0% by mass.

<Plasticizer>
The photosensitive layer of the present invention may contain a plasticizer. Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in. The plasticizer content is preferably about 30% by mass or less based on the total solid content of the photosensitive layer.

<Inorganic fine particles>
The photosensitive layer of the present invention may contain inorganic fine particles in order to improve the cured film strength of the image area. As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof can be preferably mentioned. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like. The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that is stably dispersed in the photosensitive layer, sufficiently retains the film strength of the photosensitive layer, and does not easily cause stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

<Low molecular hydrophilic compound>
The photosensitive layer of the present invention can contain a hydrophilic low molecular weight compound for improving developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Organic carboxylic acids such as salts, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, amino acids and their salts, and organic quaternary amines such as tetraethylamine hydrochloride Salt, and the like.

<Formation of photosensitive layer>
The photosensitive layer of the present invention is formed by preparing or applying 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 Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The photosensitive layer of the present invention can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times.

The coating, the photosensitive layer coating amount on the support obtained after drying (solid content) may be varied according to the intended purpose, generally 0.3 to 3.0 g / m ² is preferred. Within this range, good sensitivity and good film properties of the photosensitive layer can be obtained.
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.

(Protective layer)
The lithographic printing plate precursor according to the invention is preferably provided with a protective layer (oxygen blocking layer) on the photosensitive layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure. The protective layer used in the present invention has an oxygen permeability A at 25 ° C. and 1 atmosphere of 1.0 ≦ A ≦ 20 (mL / m ² · day
) Is preferable. When the oxygen permeability A is extremely low at less than 1.0 (mL / m ² · day), unnecessary polymerization reaction occurs at the time of production and raw storage, and unnecessary fogging and image streaking occur during image exposure. This causes the problem of overweight. Conversely, when the oxygen permeability A exceeds 20 (mL / m ² · day) and is too high, the sensitivity is lowered. The oxygen permeability A is more preferably 1.5 ≦ A ≦ 12 (mL / m ² · day), and further preferably 2.0 ≦ A ≦ 10.0 (
mL / m ² · day). In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially inhibit the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and are easy in the development process after exposure. It is desirable that it can be removed. The device concerning such a protective layer has been conventionally made, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and polyacrylamide. Or they can be mixed. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

  The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Specific examples of polyvinyl alcohol include those that are hydrolyzed by 71 to 100 mol% and have a polymerization repeating unit in the range of 300 to 2400. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8 and the like, and these can be used alone or in combination. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is 20 to 95% by mass, and more preferably 30 to 90% by mass.

  Moreover, well-known modified polyvinyl alcohol can also be used preferably. For example, various hydrophilic modification sites such as anion modification sites modified with anions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the anion-modified site, the cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol with various organic acids Examples thereof include polyvinyl alcohol having various polymerization degrees having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, and the like.

  As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoint of oxygen barrier properties and development removability, and the content in the protective layer is 3.5 to 80% by mass, preferably 10 to 60%. It is 15 mass%, More preferably, it is 15-30 mass%.

  Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. The molecular weight of the (co) polymer such as polyvinyl alcohol (PVA) can be in the range of 2000 to 10 million, preferably in the range of 20,000 to 3 million.

  As other additives to the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility, and sodium alkyl sulfate, alkyl Anionic surfactants such as sodium sulfonate; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to (co) polymers Several mass% can be added.

  In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is contained in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on a photosensitive layer. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method for the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

Furthermore, the protective layer in the lithographic printing plate precursor according to the invention preferably contains an inorganic stratiform compound for the purpose of improving oxygen barrier properties and photosensitive layer surface protection.
Here, the inorganic layered compound is a particle having a thin flat plate shape. For example, the following general formula A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
[However, A is any of K, Na, and Ca, B and C are Fe (II), Fe (III),
One of Mn, Al, Mg, and V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.

In the mica group, examples of natural mica include muscovite, soda mica, phlogopite, biotite and sericite. As the synthetic mica, fluorine phlogopite KMg ₃ (AlSi ₃ O ₁₀
) F ₂ , Potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) Non-swelling mica such as F ₂ , and Na tetrasilicic mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (N
_{a, Li) Mg 2 Li (} Si 4 O 10) F 2, montmorillonite of Na or Li hectorite _{(Na, Li) 1/8 Mg 2} /5 Li 1/8 (Si 4 O 10) F 2 , etc. Examples include swelling mica. Synthetic smectite is also useful.

In the present invention, among the inorganic layered compounds described above, fluorine-based swellable mica, which is a synthetic inorganic layered compound, is particularly useful. That is, this swellable synthetic mica and swellable viscosity minerals such as montmorillonite, saponite, hectorite, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, Atomic substitution is significantly greater than other viscous minerals. As a result, the lattice layer is deficient in positive charges, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers in order to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between the layers is Li ⁺ or Na ⁺ , since the ionic radius is small, the bond between the layered crystal lattices is weak, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swellable synthetic mica have this tendency and are useful in the present invention, and swellable synthetic mica is particularly preferably used.

  As the shape of the inorganic layered compound used in the present invention, from the viewpoint of diffusion control, the smaller the thickness, the better. The plane size is as long as it does not hinder the smoothness of the coated surface or the transmittance of actinic rays. Larger is better. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  As for the particle diameter of the inorganic stratiform compound used in the present invention, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When the inorganic layered compound particles having such a large aspect ratio are contained in the protective layer, the coating film strength is improved, and the permeation of oxygen and moisture can be effectively prevented. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.

  It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by mass ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of types of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

  Next, an example of a general dispersion method of the inorganic stratiform compound used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable layered compound mentioned above as a preferred inorganic layered compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen, and then dispersed by a disperser. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. A dispersion of 5 to 10% by mass of the inorganic stratiform compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a protective layer coating solution using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder solution.

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

  The protective layer coating solution thus prepared is applied onto the photosensitive layer provided on the support and dried to form a protective layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water. The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. . Specific examples of the protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.

The coating amount of the protective layer is preferably in the range of 0.05 to 10 g / m ^{2 in} terms of the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 0.5 g / The range of m ² is more preferable, and when the inorganic layered compound is not contained, the range of 0.5 to 5 g / m ² is more preferable.

(Support)
The support used in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like hydrophilic support. For example, paper, paper laminated with plastic (eg, 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, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. 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 preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology.
It may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it becomes easy to improve hydrophilicity and secure adhesion between the photosensitive layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like 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, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, 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.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of 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 conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, an electrolyte concentration of 1 to 80% by mass solution, a liquid temperature of 5 to 70 ° C., a current density of 5 to 60 A / d m ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains a micropore enlargement treatment, a micropore sealing treatment, and a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

Sealing treatment includes vapor sealing, single treatment with zirconic fluoride, treatment with an aqueous solution containing an inorganic fluorine compound such as treatment with sodium fluoride, vapor sealing with addition of lithium chloride, sealing with hot water. Hole processing is also possible.
Of these, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing treatment with hot water are preferable.

As hydrophilization treatment, U.S. Pat. Nos. 2,714,066, 3,181,461,
There are alkali metal silicate methods as described in the specifications of US Pat. Nos. 3,280,734 and 3,902,734. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion with the photosensitive layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

(Undercoat layer)
In the planographic printing plate precursor of the invention used in the planographic printing method of the invention, an undercoat layer can be provided between the photosensitive layer and the support, if necessary. Since the undercoat layer functions as a heat insulating layer, heat generated by exposure with an infrared laser does not diffuse to the support and can be used efficiently, so that there is an advantage that high sensitivity can be achieved. In the unexposed area, the on-press developability is improved because the photosensitive layer is easily peeled off from the support.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably.
The most preferable undercoat layer includes a polymer resin obtained by copolymerization of a monomer having an adsorptive group / a monomer having a hydrophilic group / a monomer having a crosslinkable group.

An essential component of the polymer undercoat is an adsorptive group on the surface of the hydrophilic support. The presence or absence of adsorptivity on the surface of the hydrophilic support can be determined by the following method, for example.
A coating night is prepared by dissolving the test compound in a readily soluble solvent, and the coating night is coated and dried on the support so that the coating amount after drying is 30 mg / m ² . Next, the support coated with the test compound is sufficiently washed with a readily soluble solvent, and then the residual amount of the test compound that has not been removed by washing is measured to calculate the adsorbed amount of the support. Here, the measurement of the remaining amount may be performed by directly quantifying the amount of the remaining compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. The compound can be quantified by, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, liquid chromatography measurement and the like. The compound having support adsorptivity is a compound that remains at 1 mg / m ² or more even after the above-described washing treatment.

The adsorptive group on the surface of the hydrophilic support is a substance (for example, metal, metal oxide) or a functional group (for example, hydroxyl group) existing on the surface of the hydrophilic support and a chemical bond (for example, ionic bond, hydrogen bond). , Coordination bond, bond by intermolecular force). The adsorptive group is preferably an acid group or a cationic group.
The acid group preferably has an acid dissociation constant (pKa) of 7 or less. Examples of the acid group include a phenolic hydroxyl group, a carboxyl _{group, -SO 3 H, -OSO 3 H} , -PO 3 H 2, -OPO 3 H 2, -CONHSO 2 -, - SO 2 NHSO 2 - and -COCH ₂ COCH ₃ is included. Particularly preferred are phosphoric acid groups (—OPO ₃ H ₂ , —PO ₃ H ₂ ). These acid groups may be metal salts.
The cationic group is preferably an onium group. Examples of the onium group include an ammonium group, a phosphonium group, an arsonium group, a stibonium group, an oxonium group, a sulfonium group, a selenonium group, a stannonium group, and an iodonium group. An ammonium group, a phosphonium group and a sulfonium group are preferred, an ammonium group and a phosphonium group are more preferred, and an ammonium group is most preferred.

Particularly preferred examples of the monomer having an adsorptive group include the following formula (VII) or (VIII)
The compound represented by these is mentioned.

In the formula (VII), R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms. R ¹ , R ² and R ³ are each independently preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferred is a hydrogen atom or a methyl group. R ² and R ³ are particularly preferably a hydrogen atom.
In the formula (VII), X is an oxygen atom (—O—) or imino (—NH—). X
Is more preferably an oxygen atom. In the formula (VII), L is a divalent linking group. L is a divalent aliphatic group (alkylene group, substituted alkylene group, alkenylene group, substituted alkenylene group, alkynylene group, substituted alkynylene group), divalent aromatic group (arylene group, substituted arylene group) or divalent Or an oxygen atom (—O—), a sulfur atom (—S—), an imino (—NH—), a substituted imino (—NR—, where R is an aliphatic group, an aromatic group. Or a combination with a heterocyclic group) or carbonyl (—CO—).

The aliphatic group may have a cyclic structure or a branched structure. The number of carbon atoms in the aliphatic group is preferably 1 to 20, more preferably 1 to 15, and most preferably 1 to 10. The aliphatic group is preferably a saturated aliphatic group rather than an unsaturated aliphatic group. The aliphatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aromatic group, and a heterocyclic group.
The number of carbon atoms in the aromatic group is preferably 6 to 20, more preferably 6 to 15, and most preferably 6 to 10. The aromatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aliphatic group, an aromatic group, and a heterocyclic group.
The heterocyclic group preferably has a 5-membered or 6-membered ring as the heterocycle. The heterocycle may be condensed with another heterocycle, aliphatic ring or aromatic ring. The heterocyclic group may have a substituent. Examples of substituents include halogen atoms, hydroxyl groups, oxo groups (═O), thioxo groups (═S), imino groups (═NH), substituted imino groups (═N—R, R is an aliphatic group, aromatic Group or heterocyclic group), aliphatic group, aromatic group and heterocyclic group.
L is preferably a divalent linking group containing a plurality of polyoxyalkylene structures. The polyoxyalkylene structure is more preferably a polyoxyethylene structure. In other words, L preferably contains — (OCH ₂ CH ₂ ) _n — (n is an integer of 2 or more).
In the formula (VII), Z is a functional group that adsorbs to the surface of the hydrophilic support. Y is
A carbon atom or a nitrogen atom. When Y is a nitrogen atom and L is connected to Y to form a quaternary pyridinium group, Z is not essential because it exhibits adsorptivity itself. The adsorptive functional group is as described above.
Examples of typical monomers represented by formula (VII) or (VIII) are shown below.

  Examples of the hydrophilic group of the undercoat polymer resin that can be used in the present invention include a hydroxy group, a carboxyl group, a carboxylate group, a hydroxyethyl group, a polyoxyethyl group, a hydroxypropyl group, a polyoxypropyl group, and an amino group. Preferred examples include a group, an aminoethyl group, an aminopropyl group, an ammonium group, an amide group, a carboxymethyl group, a sulfonic acid group, and a phosphoric acid group. A monomer having these hydrophilic group and polymerizable group is used as a copolymerization component of the polymer resin.

  The undercoat polymer resin used in the present invention preferably has a crosslinkable group. The crosslinkable group can improve the adhesion with the image area. In order to impart crosslinkability to the polymer resin for the undercoat, a crosslinkable functional group such as an ethylenically unsaturated bond is introduced into the side chain of the polymer or has a counter charge with the polar substituent of the polymer resin. It can be introduced by forming a salt structure with a compound having a substituent and an ethylenically unsaturated bond.

Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is A polymer having an ethylenically unsaturated bond can be mentioned.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ₁ ═CR ₂ R ₃ and — (CH ₂ CH ₂ O) ₂ —X (wherein R _{1 to} R ₃ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group. Represents an alkoxy group or an aryloxy group, and R ₁ and R ₂ or R ₃ may be bonded to each other to form a ring, n represents an integer of 1 to 10. X represents dicyclopentadi An enyl residue).
Specific examples of the ester residue include —CH ₂ CH═CH ₂ (described in JP-B-7-21633), —CH ₂ CH ₂ O—CH ₂ CH═CH ₂ , —CH ₂ C. _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 NHCOO-CH 2 CH = CH 2, and - CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ O—Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ OCO—CH═CH _2. Is mentioned.
As the monomer having a crosslinkable group of the polymer resin for undercoating, an ester or amide of acrylic acid or methacrylic acid having the crosslinkable group is preferable.

  The content of the crosslinkable group in the polymer resin for undercoat (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1 g per 1 g of the polymer resin. Is 1.0 to 7.0 mmol, most preferably 2.0 to 5.5 mmol. Within this range, both good sensitivity and dirtiness and good storage stability can be obtained.

The polymer resin for the undercoat preferably has a mass average molecular weight of 5000 or more, and is 10,000 to
The number average molecular weight is preferably 1000 or more, more preferably 2000 to 250,000, more preferably 300,000. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The undercoat polymer resin may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

As the undercoat polymer resin of the present invention, a known resin having a hydrophilic group can be used. Specific examples of such resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl 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 methacrylates, homopolymers of hydroxybutyl acrylate Copolymers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more. Polymers and copolymers, homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin A polyether etc. are mentioned.

The undercoat polymer resin may be used alone or in combination of two or more.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / ^{m 2,} and more preferably 1 to 30 mg / ^{m 2.}

(Back coat layer)
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

[Plate making method]
The lithographic printing plate precursor in the present invention is image-exposed with a light source of 350 nm to 450 nm, and then rubbed on the plate surface with a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic developing machine. The photosensitive layer in the exposed area can be removed at once to form an image on the surface of the aluminum plate support.
That is, after removing the protective layer and the non-exposed portion of the photosensitive layer at once, it can be set on a printing machine and printed immediately.
In addition, such processing in an automatic developing machine has an advantage that it is free from dealing with the development residue derived from the protective layer / photosensitive layer that occurs in the case of on-press development.

  The developer used in the present invention is an aqueous solution having a pH of 2 to 10. For example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. In particular, an aqueous solution having the same composition as that of a generally known fountain solution, a surfactant (anionic, nonionic, An aqueous solution containing a cationic system or the like, or an aqueous solution containing a water-soluble polymer compound is preferable. In particular, an aqueous solution containing both a surfactant and a water-soluble polymer compound is preferable. The pH of the developer is more preferably 3-8, and even more preferably 4-7.

The concentration of the surfactant in the developer is generally 1% by mass or more, preferably 2% by mass or more, and more preferably 5 to 20% by mass.
Examples of the anionic surfactant used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched alkyl benzene sulfonic acid salts, Alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates , Sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid compounds Glyceryl sulfate ester salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene -Partial saponifications of maleic anhydride copolymer, partial saponifications of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensate and the like. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

  It does not specifically limit as a cationic surfactant used for this invention, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

Nonionic surfactants used in the present invention include polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene. Oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. Alcohol-type glycerol fatty acid ester, pentaerythritol fatty acid ester, sorbitol and sorbita Fatty acid esters of 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 developer of the present invention is HLB (Hydrophile-Lipophile).
The (Balance) value is preferably 6 or more, and more preferably 8 or more. Furthermore, the ratio of the nonionic surfactant contained in the developer is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass.
Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicone-based surfactants can also be used in the same manner.
As the surfactant used in the developer of the present invention, a nonionic surfactant is particularly suitable from the viewpoint of foam suppression.

As the surfactant used in the developer of the present invention, as an anionic surfactant, a compound represented by any one of the following formulas (III) to (VI), a nitrogen atom-containing nonionic or cationic surfactant As the agent, a compound represented by any one of the following formulas (VII) to (IX) is particularly suitable.
The surfactant represented by any of the following formulas (III) to (IX) can be synthesized by a known method, and the molecular weight of the surfactant is generally 2000 or less, preferably 100 to 1500.

(Wherein R _{1 to} R ₁₀ each represent a hydrogen atom or an alkyl group, l represents an integer of 1 to 3, and X ₁ and X ₂ represent a sulfonate, a monoester sulfate, a carboxylate or a phosphate, respectively. And the total number of carbon atoms in R _{1 to} R ₅ or R _{6 to} R ₁₀ is 3 or more.)

In the compound corresponding to the above formula (III), the effect is seen when the total carbon number of R _{1 to} R ₅ in the formula is 3 or more, but when the total carbon number of R _{1 to} R ₅ is increased, the hydrophobic portion is increased. , It becomes difficult to dissolve in an aqueous developer. In this case, even if a dissolution aid such as an organic solvent that helps dissolution is mixed with water, the surfactant cannot be dissolved within the proper mixing range. Generally, the total number of carbons R _{1 to} R ₅ is 24 or less. More preferably, the total carbon number of R _{1 to} R ₅ is 3 to 20. Here, when R < ₁ > -R < ₅ > mentioned above is an alkyl group, the structure may be linear and may be branched.
The total number of carbons R _{1 to} R ₅ in this compound (surfactant) is influenced by the material used for the photosensitive layer, particularly the binder. In the case of a binder having high hydrophilicity, the total number of carbons of R _{1 to} R ₅ may be relatively small, but when the binder used has low hydrophilicity, the total number of carbons of R _{1 to} R ₅ needs to be increased. .
Furthermore, X _{1 in the} above compounds is in particular a sulfonate, a monoester sulfate, a carboxylate or a phosphate. Among these, sulfonate and carboxylate are particularly effective. Among these salts, alkali metal salts are particularly preferable because of their good solubility in aqueous solvents. Of these, sodium salts and potassium salts are particularly preferable. More specific examples of the compound are as follows.
The following describes the case of alkyl groups R ₁ to R ₅ does not contain oxygen atoms.

In the general formula (III), when R _{1 to} R ₅ contain at least one alkyl group containing an oxygen atom, that is, —C _m H _2m OC _nm H _{2 (nm) +1} (n ≧ 2, n ≧ m ≧ 0).
_{Here, -C m H 2m OC nm H} 2 (nm) +1 other substituents is H or alkyl group, _the total number of the carbon atoms of R 1 to R ₅ is 3 or more 24 or less. Here, since O atoms enter, it is easy to dissolve in an aqueous solvent and is often used preferably in a developer.

In the compound corresponding to the above formula (IV), the effect is seen when the total carbon number of R _{6 to} R ₁₀ in the formula is 3 or more, but the hydrophobic part increases as the total carbon number of R _{6 to} R ₁₀ increases. , It becomes difficult to dissolve in an aqueous developer. In this case, even if a dissolution aid such as an organic solvent that helps dissolution is mixed with water, the surfactant cannot be dissolved within the proper mixing range. Generally, the total number of carbons R _{6 to} R ₁₀ is 24 or less. More preferably, the total carbon number of R _{6 to} R ₁₀ is 3 to 20. Here, when R < ₆ > -R < ₁₀ > mentioned above is an alkyl group, the structure may be linear and may be branched.
The total number of carbons R _{6 to} R ₁₀ in this compound (surfactant) is affected by the material used for the photosensitive layer, particularly the binder. In the case of a binder having high hydrophilicity, the total number of carbons of R _{6 to} R ₁₀ may be relatively small, but when the binder used has low hydrophilicity, the total number of carbons of R _{6 to} R ₁₀ needs to be increased. .
Further, X _{2 in the} above compound is a sulfonate, a monoester sulfate, a carboxylate, or a phosphate. Among these, sulfonate and carboxylate are particularly effective. Among these salts, alkali metal salts are particularly preferable because of their good solubility in aqueous solvents. Of these, sodium salts and potassium salts are particularly preferable.
More specific examples of the compound are as follows.
First, it describes about the case where R < ₆ > -R < ₁₀ > is an alkyl group which does not contain an oxygen atom.

Hereinafter, when R _{6 to} R ₁₀ contain at least one alkyl group containing an oxygen atom, that is, —C _m H _2m OC _nm H _{2 (nm) +1} (n ≧ 2, n ≧ m ≧ It describes about 0). _{Here, -C m H 2m OC nm H} 2 (nm) +1 other substituents is H or alkyl group, the total number of carbon atoms is 3 or more 24 or less. Here, since O atoms enter, it is easy to dissolve in an aqueous solvent and is often used preferably in a developer.

(Wherein R _{1 to} R ₁₀ each represent a hydrogen atom or an alkyl group, l represents an integer of 1 to 3, and X ₁ and X ₂ represent a sulfonate, a monoester sulfate, a carboxylate or a phosphate, respectively. , Y ₁ and Y ₂ are —C _n H _2n —, —C _nm H _{2 (nm),} OC _m H _2m —, —O— (CH ₂ CH
_{2 O) n -, - O-} (CH 2 CH 2 CH 2 O) n - or represents -CO-NH-, n ≧ 1,
n ≧ m ≧ 0, and the total number of carbon atoms in R _{1 to} R ₅ and Y ₁ or R _{6 to} R ₁₀ and Y ₂ is 3 or more. )

In the compound corresponding to the above formula (V), the effect can be seen when the total carbon number of R _{1 to} R ₅ and Y ₁ in the formula is 3 or more. However, when the total carbon number increases, the hydrophobic portion increases, Dissolution in the developer becomes difficult. In this case, even if a dissolution aid such as an organic solvent that helps dissolution is mixed with water, the surfactant cannot be dissolved within the proper mixing range. Generally, the total carbon number is 25 or less. A more preferable total carbon number is 4-20. Here, the structure of the alkyl group described above may be linear or branched.
The total number of carbons R _{1 to} R ₅ and Y ₁ in this compound (surfactant) is influenced by the material used for the photosensitive layer, particularly the binder. In the case of a binder having high hydrophilicity, the total number of carbons of R _{1 to} R ₅ and Y ₁ may be relatively small. However, if the binder used has low hydrophilicity, the total number of carbons needs to be increased.
Further, in the above compound, X ₁ is a sulfonate, a monoester sulfate, a carboxylate, or a phosphate. Among these, sulfonate and carboxylate are particularly effective. Among these salts, alkali metal salts are particularly preferable because of their good solubility in aqueous solvents. Of these, sodium salts and potassium salts are particularly preferable. More specific examples of the compound are as follows.
The case where Y ₁ is an alkyl group containing no oxygen atom will be described below.

The following describes the case where Y ₁ contains an oxygen atom, that is, —C _nm H _{2 (nm)} OC _m H _2m — (n ≧ 1, n ≧ m ≧ 0). Here, the substituents (R _{1 to} R ₅ ) other than —C _nm H _{2 (nm)} OC _m H _2m — are hydrogen atoms or alkyl groups, and the total number of carbon atoms is 3 or more and 25 or less. Here, since O atoms enter, it is easy to dissolve in an aqueous solvent, and is often used favorably in a developer.

In the compound corresponding to the above formula (VI), the effect can be seen when the total carbon number of R _{6 to} R ₁₀ and Y ₂ in the formula is 3 or more. Is difficult to dissolve in a developer. In this case, even if a dissolution aid such as an organic solvent that helps dissolution is mixed with water, the surfactant cannot be dissolved within the proper mixing range. Generally, the total carbon number is 25 or less. A more preferable total carbon number is 3-20. Here, the structure of the alkyl group described above may be linear or branched.
The total number of carbons R _{6 to} R ₁₀ and Y ₂ in this compound (surfactant) is influenced by the material used for the photosensitive layer, particularly the binder. In the case of a binder having high hydrophilicity, the total number of carbons of R _{6 to} R ₁₀ and Y ₂ may be relatively small. However, if the binder used has low hydrophilicity, the total number of carbons needs to be increased.
Further, X _{2 in the} above compound is a sulfonate, a monoester sulfate, a carboxylate, or a phosphate. Among these, sulfonate and carboxylate are particularly effective. Among these salts, alkali metal salts are particularly preferable because of their good solubility in aqueous solvents. Of these, sodium salts and potassium salts are particularly preferable.
More specific examples of the compound are as follows.

Hereinafter, the case where Y ₂ contains an oxygen atom, that is, C _nm H _{2 (nm)} OC _m H _2m (n ≧ 1, n ≧ m ≧ 0) will be described. Here, substituents (R _{6 to} R ₁₀ ) other than C _nm H _{2 (nm)} OC _m H _2m are hydrogen atoms or alkyl groups, and the total number of carbon atoms is 3 or more and 25 or less. Here, since O atoms enter, it is easy to dissolve in an aqueous solvent, and is often used favorably in a developer.

(In the formula (VII), Ra represents a hydrogen atom or an alkyl group, and A and B are groups containing an ethylene oxide group, a carboxylic acid group, or a carboxylate.
In the formula (VIII), Rb and Rc represent a hydrogen atom or an alkyl group, C represents an alkyl group or a group containing an ethylene oxide group, and D represents a group containing a carboxylate anion.
In formula (IX), Rd, Re, Rf and Rg each represent a hydrogen atom or an alkyl group, and Z ⁻ is a counter anion. The alkyl group of Ra to Rg may have a substituent. )

  Although it does not specifically limit as a compound (henceforth a surfactant) represented by the said formula (VII), (VIII) or (IX), A typical thing is shown below.

(In the formula, R11 to R13, R15, R16, R18, R21, and R24 to R27 each represent a hydrogen atom or an alkyl group. R14, R17, R19, R20, R22, and R23 each represent an alkylene group or a single bond)

In the compound corresponding to the above formula (10), R11 to R13 in the formula are a hydrogen atom or an alkyl group, and R14 is an alkylene group. However, N and a carboxyl group may be directly connected, and in this case, R14 is a single bond.
In the compound (10), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in an aqueous developer. In this case, mixing with a water-soluble dissolution aid such as an organic solvent or alcohol that aids dissolution will improve, but if the total carbon number becomes too large, the surfactant will be dissolved within the proper mixing range. It is not possible. Here, the total carbon number of R11 to R14 is preferably 10 to 40, more preferably 12 to 30.
Here, when R11 to R13 described above are alkyl groups, the structure may be linear or branched.
The carbon number of R11 to R14 in these compounds (surfactants) is influenced by the material used for the photosensitive layer, particularly the binder. In the case of a binder having a high hydrophilicity, those having a relatively small carbon number of R11 to R14 tend to be preferable, and those having a low hydrophilicity are preferably those having a large carbon number of R11 to R14.
Typical compounds include those shown below.

In the compound corresponding to the above formula (11), R15 to R16 in the formula are a hydrogen atom or an alkyl group, and R17 is an alkylene group. However, N and a carboxyl group may be directly connected, and in this case, R17 does not exist. Similarly to the compound (10), in the compound (11), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in the aqueous developer. In this case, mixing with a water-soluble dissolution aid such as an organic solvent or alcohol that aids dissolution will improve, but if the total carbon number becomes too large, the surfactant will be dissolved within the proper mixing range. It is not possible. Here, the total number of carbon atoms of R15 to R17 is preferably 10 to 30, and more preferably 12 to 25.
Here, when R11 to R14 described above are alkyl groups, the structure may be linear or branched.
The carbon number of R15 to R17 in these compounds (surfactants) is influenced by the material used for the photosensitive layer, particularly the binder. In the case of a binder having a high degree of hydrophilicity, the carbon number of R15 to R17 tends to be relatively small, and the binder having a low degree of hydrophilicity is preferably R15 to R17.
Those having a large carbon number are preferred.
Further, in the above compounds, X + includes monovalent metal ions such as potassium ion and sodium ion, divalent metal ions such as calcium ion and magnesium ion, ammonium ion and hydrogen ion. Among the compounds (11), sodium ion and potassium are particularly preferably used. Typical compounds include those shown below.

In the compound corresponding to the formula (12), R18 in the formula is a hydrogen atom or an alkyl group, and R19 and R20 are alkylene groups. However, N and a carboxyl group may be directly connected, and in this case, R19 and 20 do not exist. Similarly to the compounds (10) and (11), in the compound (12), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in the aqueous developer. In this case, mixing with a water-soluble dissolution aid such as an organic solvent or alcohol that aids dissolution will improve, but if the total carbon number becomes too large, the surfactant will be dissolved within the proper mixing range. It is not possible. Here, the total number of carbon atoms of R18 to R20 is preferably 10 to 30, more preferably 12 to 28.
Here, when R18 described above is an alkyl group, the structure may be linear or branched.
The carbon number of R18 to R20 in these compounds (surfactants) is influenced by the material used for the photosensitive layer, particularly the binder. In the case of a binder having a high hydrophilicity, those having a relatively small carbon number of R18 to R20 tend to be preferable, and those having a low hydrophilicity are preferably those having a large carbon number of R18 to R20.
Further, in the above compounds, for X ⁺ and Y ⁺ , in addition to monovalent metal ions such as potassium ion and sodium ion, divalent metal ions such as calcium ion and magnesium ion, ammonium ion and hydrogen ion are used. It is done. Among the compounds (12), sodium ion and potassium are particularly preferably used. Typical compounds include those shown below.

In the compound corresponding to the above formula (13), R21 in the formula is a hydrogen atom or an alkyl group, and R22 and R23 are alkylene groups. However, N and ethylene oxide may be directly connected, and in this case, R22 and 23 do not exist. Also in the compound (13), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in the aqueous developer. In this case, mixing with a water-soluble dissolution aid such as an organic solvent or alcohol that aids dissolution will improve, but if the total carbon number becomes too large, the surfactant will be dissolved within the proper mixing range. It is not possible. Here, the total number of carbon atoms of R21 to R23 is preferably 8 to 50, and more preferably 12 to 40.
Here, when R21 described above is an alkyl group, the structure thereof may be linear or branched.
The carbon number of R21 to R23 in these compounds (surfactants) is influenced by the material used for the photosensitive layer, particularly the binder. In the case of a binder having a high hydrophilicity, those having a relatively small number of carbon atoms in R21 to R23 tend to be preferable, and those having a low hydrophilicity are used in R21 to R23.
Those having a large carbon number are preferred.
About m and n showing the number of ethylene oxide, if it becomes large, a hydrophilic degree will increase and stability in water will increase. m and n may be the same number or different numbers. Typical compounds include those shown below. m is generally 1-20, and n is generally 1-20.

In the compound corresponding to the above formula (14), R24 to R27 in the formula are a hydrogen atom or an alkyl group.
Also in the compound (14), when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in the aqueous developer. In this case, mixing with a water-soluble dissolution aid such as an organic solvent or alcohol that aids dissolution will improve, but if the total carbon number becomes too large, the surfactant will be dissolved within the proper mixing range. It is not possible. Here, the total number of carbon atoms of R24 to R27 is preferably 10 to 30, and more preferably 12 to 28.
Here, when R24 to R27 described above are alkyl groups, the structure thereof may be linear or branched.
The carbon number of R24 to R27 in these compounds (surfactants) is influenced by the material used for the photosensitive layer, particularly the binder. In the case of a binder having a high hydrophilicity, those having a relatively small carbon number of R24 to R27 tend to be preferable, and those having a low hydrophilicity are preferably those having a large carbon number of R24 to R27.
Z ⁻ represents a counter anion. Although these are not limited, Cl ⁻ , Br ⁻ , I ^{− and the} like are often used. Typical compounds include those shown below.

  Examples of the water-soluble polymer compound used in the developer of the present invention include soybean polysaccharide, modified starch, gum arabic, dextrin, fibrin derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan. , Polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, etc. It is done.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

  As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.

Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, and more preferably from 0.5 to 10% by mass.

  Further, the developer of the present invention may contain an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). And xylene), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.), and polar solvents.

  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 monoethyl ether , Propylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, etc.) , (Acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl acetate, propylene Glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).

  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 developer contains an organic solvent, safety, ignition, From the viewpoint of property, the concentration of the solvent is preferably less than 40% by mass.

  In addition to the above, the developer of the present invention may contain a preservative, a chelate compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like.

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzisothiazolin-3-one, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, pyridine, Derivatives such as quinoline and guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.

  Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.

As the antifoaming agent, a general silicone-based self-emulsifying type, emulsifying type, nonionic surfactant having a HLB of 5 or less can be used. Silicone defoamers are preferred.
Among them, emulsification dispersion type and solubilization can be used.

  Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples thereof include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like.

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

  The development treatment with an aqueous solution having a pH of 2 to 10 in the present invention can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs a rubbing process while transporting a lithographic printing plate precursor after image recording, or a cylinder Examples thereof include an automatic processor described in US Pat. Nos. 5,148,746, 5,568,768 and British Patent 2,297,719, which rub the lithographic printing plate precursor after image recording set thereon while rotating a cylinder. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

The rotating brush roll that can be preferably used in the present invention can be appropriately selected 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, as described in Japanese Patent Application Laid-Open No. 58-159533, Japanese Patent Application Laid-Open No. 3-100554, or Japanese Utility Model Publication No. 62-167253, metal or plastic in which brush materials are implanted in rows. A brush roll can be used in which the groove mold material is radially wound around a plastic or metal roll as a core without a gap.
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. 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.
Moreover, it is preferable to use two or more rotating brush rolls.

  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 planographic printing plate precursor of the present invention. Thus, 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.

  Although the temperature of the developer can be used at any temperature, it is preferably 10 ° C to 50 ° C.

  In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water, dried and desensitized. In the desensitizing treatment, a known desensitizing solution can be used.

  In addition, as the plate-making process of the lithographic printing plate from the lithographic printing plate precursor according to the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. By such heating, the image forming reaction in the photosensitive layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. Further, for the purpose of improving the image strength and printing durability, it is also effective to subject the developed image to full post heating or full exposure. Usually, the heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, problems such as covering up to the non-image area occur. Very strong conditions are used for heating after development. Usually, it is the range of 200-500 degreeC. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

The plate making process will be further described in detail.
In the present invention, as described above, the development treatment may be performed immediately after the exposure step, but a heat treatment step may be provided between the exposure step and the development step. This heat treatment has the effect of improving the printing durability and further improving the uniformity of the image curing degree within the plate surface, and the conditions can be appropriately set within the range where these effects are present. Examples of the heating means include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. For example, it can be carried out by holding the plate surface temperature in the range of 70 to 150 ° C. for 1 second to 5 minutes. Preferably, the temperature is 80 ° C to 140 ° C for 5 to 1 minute, more preferably 90 ° C to 130 ° C for 10 to 30 seconds. This range is preferable in that the above effect can be obtained efficiently and there is no adverse effect such as deformation of the printing plate due to heat.
In the present invention, a development processing step is performed after the above-described exposure step and preferably the heat treatment step to obtain a lithographic printing plate. The plate setter used in the exposure process, the heat treatment means used in the heat treatment, and the developing device used in the development process are preferably connected to each other and automatically continuously processed. Specifically, it is a plate making line in which a plate setter and a developing device are coupled by a conveying means such as a conveyor. A heat treatment unit may be provided between the plate setter and the developing device, and the heating unit and the developing device may be integrated.

When the printing plate to be used is easily affected by ambient light in the work environment, it is preferable that the plate making line is shielded by a filter or a cover.
After the image is formed as described above, the entire surface may be exposed with an actinic ray such as ultraviolet light to accelerate the curing of the image area. Examples of the light source for the entire surface exposure include a carbon arc lamp, a mercury lamp, a gallium lamp, a metal halide lamp, a xenon lamp, a tungsten lamp, and various laser lights. Furthermore, in order to obtain sufficient printing durability, the overall exposure amount is preferably at least 10 mJ / cm ² or more, more preferably 100 mJ / cm ² or more.
Heating may be performed simultaneously with the entire surface exposure, and further improvement in printing durability is recognized by heating. Examples of the heating device include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. At this time, the plate surface temperature is preferably 30 ° C to 150 ° C, more preferably 35 ° C to 130 ° C, and still more preferably 40 ° C to 120 ° C.

Prior to the above development processing, the lithographic printing plate precursor is exposed through a transparent original image having a line image, a halftone dot image or the like, or imagewise exposed by laser beam scanning or the like using digital data.
A desirable wavelength of the light source is 350 nm to 450 nm, and specifically, an InGaN semiconductor laser is suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.

Other exposure light beams that can be used in the present invention include ultrahigh pressure, high pressure, medium pressure, and low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, various visible and ultraviolet laser lamps, fluorescent lamps, and the like. A lamp, a tungsten lamp, sunlight, etc. can also be used.
As available laser light sources of 350 nm to 450 nm, the following can be used.
As a gas laser, an Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), a Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), a He-Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and a solid laser as Nd: YAG (YVO ₄ ) and SHG crystal × 2 combinations (355 nm, 5 mW to 1 W), Cr: LiSAF and SHG crystal combination (430 nm, 10 mW), as a semiconductor laser system, KNbO ₃ ring resonator (430 nm, 30 mW), Waveguide type wavelength conversion element and AlGaAs
, InGaAs semiconductor combinations (380 nm to 450 nm, 5 mW to 100 mW), waveguide wavelength conversion elements and AlGaInP, AlGaAs semiconductor combinations (300 nm to 350 nm, 5 mW to 100 mW), AlGaInN (350 nm to 450 nm, 5 mW to 30 mW), others , N ₂ laser (337 nm, pulse 0.1-1 as the pulse laser
0 mJ), XeF (351 nm, pulse 10-250 mJ). In particular, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 400 to 410 nm, 5 to 30 mW) is preferable in terms of wavelength characteristics and cost.

Further, as the lithographic printing plate exposure apparatus of the scanning exposure method, there are an inner drum method, an outer drum method, and a flat bed method as an exposure mechanism, and a light source that can continuously oscillate among the light sources can be preferably used. . Practically, the following exposure apparatus is particularly preferable in terms of the relationship between the photosensitive material sensitivity and the plate making time.
・ Single beam to triple beam exposure equipment that uses one or more gas lasers or solid-state laser light sources so that it becomes a semiconductor laser with a total output of 20 mW or more with an internal drum system. ・ A total output of 20 mW or more with a flat bed system. Multi-beam (1 to 10) exposure equipment that uses one or more semiconductor lasers, gas lasers, or solid-state lasers • Use one or more semiconductor lasers, gas lasers, or solid-state lasers to achieve a total output of 20 mW or more with the external drum system Multi-beam (1 to 9) exposure apparatus ・ Multi-beam (10 or more) exposure apparatus using one or more semiconductor lasers or solid-state lasers so that the total output is 20 mW or more by the external drum system.

In the laser direct-drawing lithographic printing plate as described above, the photosensitive material sensitivity X (J / cm ²⁾ is generally used.
), Exposure area S (cm ² ) of photosensitive material, power q (W) of one laser light source, number of lasers n
The equation (eq1) is established between the total exposure time t (s).

  X · S = n · q · t (eq 1)

i) In the case of the internal drum (single beam) system, the laser rotation speed f (radians / s), the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dots / cm), and the total exposure time t (s) In general, equation (eq 2) holds.

  f · Z · t = Lx (eq 2)

ii) External drum (multi-beam) system Drum rotation speed F (radians / s), photosensitive material sub-scanning length Lx (cm), resolution Z (dots / cm), total exposure time t (s), number of beams In general, formula (eq 3) is established during (n).

  F.Z.n.t = Lx (eq 3)

iii) Flat head (multi-beam) system Polygon mirror rotation speed H (radians / s), photosensitive material sub-scanning length Lx (cm), resolution Z (dots / cm), total exposure time t (s), Equation (eq 4) is generally established between the number of beams (n).

  F.Z.n.t = Lx (eq 4)

Resolution (2560 dpi) required for the actual printing plate, plate size (A1 / B1, sub-scan length 42 inch), exposure conditions of about 20 sheets / hour and photosensitive characteristics of the planographic printing plate precursor of the present invention (photosensitive wavelength, By substituting (sensitivity: about 0.1 mJ / cm ² ) into the above formula, it is understood that a combination with a multi-beam exposure method using a laser having a total output of 20 mW or more is particularly preferable in the planographic printing plate precursor of the present invention. it can. Further, by combining operability, cost, etc., a combination with an external drum type semiconductor laser multi-beam (10 or more) exposure apparatus is most preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

[Preparation of Support 1]
An aluminum plate (material JIS A1050) having a thickness of 0.3 mm was etched by being immersed in 10% by weight sodium hydroxide at 60 ° C. for 25 seconds, washed with running water, neutralized with 20% by weight nitric acid, and then washed with water. . This was subjected to an electrolytic surface roughening treatment in a 1% by mass nitric acid aqueous solution using a sinusoidal alternating waveform current at an anode time electricity of 300 coulomb / dm ² . Subsequently 1% by mass
After dipping in an aqueous solution of sodium hydroxide at 40 ° C. for 5 seconds and then in a 30% by weight sulfuric acid aqueous solution and desmutting at 60 ° C. for 40 seconds, in a 20% by weight aqueous sulfuric acid solution at a current density of 2 A / dm ² . Anodization was performed for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² .
Then, it processed at 20 degreeC for 10 second with 1 mass% of sodium silicate aqueous solution.
The center line average roughness (Ra) of the support thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.25 μm (Ra indication according to JIS B0601).

Furthermore, after applying the following undercoat liquid (1) with a bar, it was oven-dried at 80 ° C. for 10 seconds to apply a dry coating amount of 10 mg / m ² , and a support having an undercoat layer used in the following experiments Produced.

<Undercoat liquid (1)>
・ Undercoat compound (1) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

[Preparation of lithographic printing plate precursor (1)]
A photosensitive layer coating solution (1) having the following composition was bar coated on the support provided with the undercoat layer, followed by oven drying at 70 ° C. for 60 seconds, and a photosensitive layer having a dry coating amount of 1.1 g / m ² . A protective layer coating solution (1) having the following composition is applied on the substrate using a bar so that the dry coating amount is 0.75 g / m ^2, and then dried at 125 ° C. for 70 seconds. Thus, a lithographic printing plate precursor (1) was obtained.

<Photosensitive layer coating solution (1)>
-The following binder polymer (1) (acid value 0 meq / g, weight average molecular weight 80,000)
0.54g
・ Polymerizable compound 0.48g
(Dipentaerythritol pentaacrylate, Nippon Kayaku Co., Ltd., SR399E)
-The following sensitizing dye (1) (absorption maximum wavelength: 364 nm) 0.06 g
・ The following polymerization initiator 0.18 g
・ The following co-sensitizer (1) 0.02 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant Binder polymer (1): 10 parts by mass, solvent cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass)
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt ・ The following water-soluble fluorosurfactant (1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylamine hydrochloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

Protective layer coating solution (1)
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 40 g
Polyvinylpyrrolidone (molecular weight 50,000) 5g
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 70,000 0.5g
Surfactant 0.5g
(Polyoxyethylene lauryl ether, Emarex 710, manufactured by Nippon Emulsion Co., Ltd.)
950g of water

[Preparation of lithographic printing plate precursor (2)]
The lithographic printing plate precursor (1) except that the binder polymer (1) in the photosensitive layer coating solution (1) was changed to the following binder polymer (5) (acid value 1.9 meq / g, weight average molecular weight 80,000). A lithographic printing plate precursor (2) was obtained in the same manner as in the preparation.

[Preparation of lithographic printing plate precursor (3)]
A lithographic printing plate precursor (3) was obtained in the same manner as the production of the lithographic printing plate precursor (1) except that the photosensitive layer coating solution (1) was changed to a photosensitive layer coating solution (2) having the following composition.

<Photosensitive layer coating solution (2)>
・ 0.2 g of the above polymerization initiator (1)
-0.1 g of the above sensitizing dye (1)
・ Binder polymer (1) (average molecular weight 80,000) 3.0 g
-Polymerizable compound 6.2g
Isocyanuric acid EO-modified diacrylate (Aronix M-215 manufactured by Toa Gosei Co., Ltd.)
・ Royco Crystal Violet 0.2g
・ 0.1 g of the above-mentioned fluorosurfactant (1)
・ The following microcapsule (1) dispersion 25.0 g
・ Methyl ethyl ketone 35.0g
・ 3-methoxy-2-propanol 35.0 g

(Synthesis of microcapsule (1))
As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (manufactured by Mitsui Takeda Chemical Co., Ltd., Takenate D-110N) 10 g, dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd., SR399E) 4.15 g And 0.1 g of Pionein A-41C (manufactured by Takemoto Oil & Fat Co., Ltd.) were dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours. The microcapsule liquid (1) thus obtained was diluted with distilled water so that the solid content concentration became 20% by mass. The average particle size was 0.25 μm.

[Preparation of lithographic printing plate precursor (4)]
Except for changing the binder polymer (1) of the photosensitive layer coating solution (1) to the following binder polymer (2) (acid value 0 meq / g, weight average molecular weight 70,000), the same as the lithographic printing plate precursor (1), A lithographic printing plate precursor (4) was obtained.

[Preparation of lithographic printing plate precursor (5)]
Except for changing the binder polymer (1) of the photosensitive layer coating solution (1) to the following binder polymer (3) (acid value 0 meq / g, weight average molecular weight 100,000), the same as the lithographic printing plate precursor (1), A lithographic printing plate precursor (5) was obtained.

[Preparation of lithographic printing plate precursor (6)]
Except for changing the binder polymer (1) of the photosensitive layer coating solution (1) to the following binder polymer (4) (acid value 0 meq / g, weight average molecular weight 90,000), the same as the lithographic printing plate precursor (1), A lithographic printing plate precursor (6) was obtained.

[Preparation of lithographic printing plate precursor (7)]
The lithographic printing plate precursor (7) was prepared in the same manner as the lithographic printing plate precursor (1) except that the cosensitizer (1) in the photosensitive layer coating solution (1) was changed to the following cosensitizer (2). Obtained.

[Preparation of lithographic printing plate precursor (8)]
The lithographic printing plate precursor (8) was prepared in the same manner as the lithographic printing plate precursor (1) except that the cosensitizer (1) in the photosensitive layer coating solution (1) was changed to the following cosensitizer (3). Obtained.

[Preparation of lithographic printing plate precursor (9)]
The lithographic printing plate precursor except that the protective layer coating solution (1) is changed to a protective layer coating solution (2) having the following composition and coated using a bar so that the dry coating amount is 0.2 g / m ^2. A lithographic printing plate precursor (9) was obtained in the same manner as in the preparation of (1).

Protective layer coating solution (2)
・ The following mica dispersion (1) 13.0 g
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 1.3 g
-Sodium 2-ethylhexyl sulfosuccinate 0.2g
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 70,000 g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.05g
・ 133g of water

(Preparation of mica dispersion (1))
To 368 g of water, 32 g of synthetic mica (“Somasif ME-100”: manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1000 or more) is added and dispersed using an homogenizer until the average particle size (laser scattering method) becomes 0.5 μm. A mica dispersion (1) was obtained.

[Preparation of lithographic printing plate precursor (10)]
A lithographic printing plate precursor (10) was obtained in the same manner as the production of the lithographic printing plate precursor (1) except that the support was changed to the following support 2.

(Preparation of support 2)
In order to remove rolling oil on the surface of an aluminum plate (material JIS A1050) having a thickness of 0.3 mm, a degreasing treatment is performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter is 0.3 mm. The aluminum surface was grained using 3 bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed well with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode.
The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode.
Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a DC anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, then washed with water and dried. Then, it processed at 20 degreeC for 10 second with 1 mass% of sodium silicate aqueous solution.
The center line average roughness (Ra) of the support thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.51 μm (Ra indication according to JIS B0601).

After applying the following undercoat liquid (2) to the thus treated aluminum plate with a bar, it was oven dried at 80 ° C. for 20 seconds to apply a dry coating amount of 10 mg / m ² to prepare a support. did.

Undercoat liquid (2)
・ 100g of the following sol solution
・ Methanol 900g

Sol solution ・ Phosmer PE (Unichemical Co., Ltd.) 5g
・ Methanol 45g
・ Water 10g
・ 85% phosphoric acid 5g
・ Tetraethoxysilane 20g
・ 3-Methacryloxypropyltrimethoxysilane 15g

[Preparation of lithographic printing plate precursor (11)]
The lithographic printing plate precursor (11) is prepared in the same manner as in the production of the lithographic printing plate precursor (1) except that the sensitizing dye (1) in the photosensitive layer coating solution (1) is changed to the following sensitizing dye (2). Got.

[Preparation of lithographic printing plate precursor (12)]
The lithographic printing plate precursor (12) is prepared in the same manner as in the production of the lithographic printing plate precursor (1) except that the sensitizing dye (1) in the photosensitive layer coating solution (1) is changed to the following sensitizing dye (3). Got. The absorption maximum wavelength of the sensitizing dye (3) is 387 nm.

[Examples 1-9, 13 and Comparative Examples 1-2]
(1) Exposure, development and printing For each of the above lithographic printing plate precursors (1) to (10), imagewise exposure was performed using a 405 nm semiconductor laser with an output of 100 mW while changing the energy density.
Thereafter, the developing solution (1) having the following composition was used, and development processing was carried out with an automatic developing processor having a structure shown in FIG. The pH of the developer was 5. The automatic processor is an automatic processor having two rotating brush rolls. As the rotating brush roll, the first brush roll has a polybutylene terephthalate fiber (hair diameter 200 μm, hair length 17 mm). ) Is used, and the second brush roll is made of polybutylene terephthalate at a speed of 200 revolutions per minute (peripheral speed of the brush tip of 0.52 m / sec) in the same direction as the conveying direction. Using a brush roll with an outer diameter of 50 mm in which fibers (hair diameter 200 μm, hair length 17 mm) are implanted, rotate 200 times per minute in the direction opposite to the conveying direction (peripheral speed of brush tip 0.52 m / sec) It was. The planographic printing plate precursor was transported at a transport speed of 100 cm / min.
The developer was showered from the spray pipe with a circulation pump and supplied to the plate surface. The tank capacity of the developer was 10 liters.

Developer (1)
・ Water 100g
・ Benzyl alcohol 1g
・ Polyoxyethylene naphthyl ether (average number of oxyethylene n = 13)
(Nippon Emulsifier Co., Ltd. New Coal B13) 1g
・ Dioctyl sulfosuccinate sodium salt 0.5g
・ 1g gum arabic
・ Ethylene glycol 0.5g
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Ethylenediaminetetraacetate tetrasodium salt 0.05g

  Subsequently, the developed lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and dampening water (EU-3 (Etchi solution manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10. (Capacity ratio)) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) were used for printing at a printing speed of 6000 sheets per hour.

(2) Evaluation Using the lithographic printing plate precursor prepared earlier, sensitivity and safelight suitability were evaluated as follows.

<Sensitivity>
As described above, 100 sheets were printed, and after confirming that a printed matter having no ink stains in the non-image area was obtained, 500 sheets were continuously printed. In the total 600th printed matter, the exposure amount with no unevenness in the ink density in the image area was measured as sensitivity.

<Developability>
The obtained lithographic printing plate precursor was exposed and developed as described above. After the development processing, the non-image area of the lithographic printing plate was visually confirmed to evaluate the presence or absence of the remaining photosensitive layer.
<Safelight suitability>
The obtained lithographic printing plate precursor was exposed to yellow light (wavelength of 500 nm or less, cut fluorescent light, illuminance of 250 lux) for 10, 20, and 30 minutes before image exposure, and then exposed and developed as described above. . After the development process, the non-image area of the lithographic printing plate was visually confirmed to evaluate the presence or absence of fogging (remaining photosensitive layer).
The results are shown in Table 1.

Example 10
Image exposure, development processing and printing were carried out in the same manner as in Example 1 except that the second brush roll of the automatic processor was removed and development was performed. Became a little worse.

Example 11
The polyoxyethylene naphthyl ether in the developer (1) is changed to an anionic surfactant (polyoxyethylene naphthyl ether sulfate ester, New Coal B4SN manufactured by Nippon Emulsifier Co., Ltd.) having the following structural formula, and the antifoaming agent FS Antihome DR110N Image exposure, development treatment and printing were carried out in the same manner as in Example 1 except that 0.1 g of (Dow Corning, silicone emulsion) was added, and the same evaluation results as in Example 1 were obtained. The pH of this developer was 5.

Example 12
Image exposure, development treatment and printing were carried out in the same manner as in Example 1 except that the developer (1) was changed to the developer (2) shown below. The same evaluation results as in Example 1 were obtained. Developer (
The pH of 2) was 4.5.

Developer (2)
・ Water 100g
・ Sodium alkylnaphthalenesulfonate 5g
(Perox NB-L manufactured by Kao Corporation)
・ 1g gum arabic
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Ethylenediaminetetraacetate tetrasodium salt 0.05g

Example 14
Within 30 seconds after the image exposure, the lithographic printing plate precursor was placed in an oven, hot air was blown to heat the entire surface of the lithographic printing plate precursor, and held at 110 ° C. for 15 seconds. Thereafter, image exposure, development processing and printing were performed in the same manner as in Example 12 except that the same development processing as in Example 12 was performed within 30 seconds.
The sensitivity was 0.09 mJ / cm ² by the heat treatment, and the developability and the safelight suitability were good without remaining the photosensitive layer in the non-image area.

Example 15
The lithographic printing plate precursor (1) was subjected to image exposure using a violet semiconductor laser plate setter Vx9600 (equipped with InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW) manufactured by FUJIFILM Electronic Imaging Ltd. The image was drawn using a FM screen (TAFFETA 20) manufactured by Fuji Photo Film Co., Ltd. with a resolution of 2438 dpi, and a 35% flat screen was drawn with a plate exposure of 0.09 mJ / cm ² . Within 30 seconds after image exposure of the exposed lithographic printing plate precursor, development processing was carried out using an automatic processor LP1250PLX manufactured by Fuji Photo Film Co., Ltd. The automatic processor is configured in the order of heating unit / washing unit / developing unit / rinsing unit / finishing unit. The heating condition of the heating unit is 100 ° C. for 10 seconds, and the washing unit, developing unit, rinsing unit All the baths in the unit / finishing unit were charged with the developer (2). The temperature of the developer was 28 ° C., and the planographic printing plate was transported at a transport speed of 110 cm / min.
After development, the non-image area and the image of the lithographic printing plate were visually confirmed. As a result, the photosensitive layer did not remain in the non-image area, and a uniform flat net image without unevenness was formed. Further, when this lithographic printing plate was printed under the above-mentioned printing conditions, a good printed product with a uniform flat net image having no non-image area stains and no unevenness was obtained.

Example 16
Image exposure, development treatment and printing were carried out in the same manner as in Example 1 except that the developer (1) was changed to the developer (3) below. The same evaluation results as in Example 1 were obtained. The pH of the developer (3) was 4.0.

Developer (3)
・ Water 100g
・ Polyoxyethylene lauryl amino ether 10g
(Pionein D3110 manufactured by Takemoto Yushi Co., Ltd.)
・ Polystyrenesulfonic acid 1g
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Ethylenediaminetetraacetate tetrasodium salt 0.05g

Example 17
The same procedure as in Example 16 was conducted except that polyoxyethylene lauryl amino ether (Pionine D3110, Takemoto Yushi Co., Ltd.) in the developer (3) was changed to N-lauryl dimethyl betaine (Pionine C157K, Takemoto Yushi Co., Ltd.). When image exposure, development processing and printing were performed, the same evaluation results as in Example 16 were obtained. The pH of this developer was 4.0.

Example 18
Lithographic printing was carried out in the same manner as in Example 15 except that instead of the developer (2), the developer (3) was charged in the bath of the developing unit and the finishing unit, and water was charged in the bath of the washing unit and the rinse unit. The plate precursor (1) was subjected to image exposure and development processing.
After development, the non-image area and the image of the lithographic printing plate were visually confirmed. As a result, the photosensitive layer did not remain in the non-image area, and a uniform flat net image without unevenness was formed. Further, when this lithographic printing plate was printed under the above-mentioned printing conditions, a good printed product with a uniform flat net image having no non-image area stains and no unevenness was obtained.

[Examples 19 to 23]
An 8% by mass aqueous solution of each surfactant shown in Table 2 was prepared, and the lithographic printing plate precursor (1) was immersed in each aqueous solution while changing the immersion time in steps of 5 seconds. After immersion, the plate surface was rubbed with a sponge, washed with water, and the time until the photosensitive layer was removed was evaluated as the development time. (The shorter the time, the better the developability.)

  It can be seen that better development is possible by using a developer containing a specific preferred surfactant.

Structure of automatic processor

Explanation of symbols

1: rotating brush roll 2: receiving roll 3: transport roll 4: transport guide plate 5: spray pipe 6: pipeline 7: filter 8: plate supply table 9: plate discharge table 10: developer tank 11: circulation pump 12: plate

Claims (20)

On the hydrophilic support, (A) a sensitizing dye having an absorption maximum at 350 to 450 nm represented by the following general formula (I) or (II), (B) a polymerization initiator, (C) a polymerizable compound, (D) A photosensitive layer containing a hydrophobic binder polymer having a solubility in water at 25 ° C. and an aqueous solution having a pH of 10 or higher of 0.5% by mass or less and an acid value of 0.3 meq / g or less, and a protective layer After the lithographic printing plate precursor having laser exposure at 350 to 450 nm, the protective layer and rubbing member are rubbed by an automatic processor equipped with a rubbing member in the presence of a developer having a pH of 2 to 10 A method for preparing a lithographic printing plate, comprising removing a photosensitive layer in a non-exposed portion.


R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
R ¹⁵ to R ³² each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a cyano group or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms. (D) The method for producing a lithographic printing plate according to claim 1, wherein the hydrophobic binder polymer is a (meth) acrylic resin or a polyurethane resin. (B) a polymerization initiator, a method of preparing a lithographic printing plate according to claim 1 or 2 characterized in that it is a hexaarylbiimidazole compound. The method for preparing a lithographic printing plate according to claim 3 , wherein the photosensitive layer further comprises (E) a chain transfer agent. (E) The method for producing a lithographic printing plate according to claim 4 , wherein the chain transfer agent is a thiol compound represented by the following general formula.

Here, R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A represents a 5-membered or 6-membered ring having a carbon atom together with an N = CN moiety. The atomic group which forms the heterocyclic ring of A, and A may further have a substituent. (D) The hydrophobic binder polymer is at least one selected from the group consisting of a (meth) acrylic copolymer having a crosslinkable group in the side chain and a polyurethane resin having a crosslinkable group in the side chain. A method for producing a lithographic printing plate according to any one of claims 1 to 5 . The method for preparing a lithographic printing plate according to any one of claims 1 to 6 , wherein a part or all of the photosensitive layer component is encapsulated in a microcapsule. The method of preparing a lithographic printing plate according to any one of claims 1 to 7 , wherein the rubbing member is at least two rotating brush rolls. The method of preparing a lithographic printing plate according to any one of claims 1 to 8, wherein the pH of the developer is from 3 to 8. The method for producing a lithographic printing plate according to any one of claims 1 to 9 , further comprising heat-treating the exposed lithographic printing plate precursor between exposure and development. On the hydrophilic support, (A) a sensitizing dye having an absorption maximum at 350 to 450 nm represented by the following general formula (I) or (II), (B) a polymerization initiator, (C) a polymerizable compound, (D) A photosensitive layer containing a hydrophobic binder polymer having a solubility in water at 25 ° C. and an aqueous solution having a pH of 10 or higher of 0.5% by mass or less and an acid value of 0.3 meq / g or less, and a protective layer A lithographic printing plate precursor having a laser exposure at 350 to 450 nm, and then protected by rubbing the plate surface with a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic processor equipped with a rubbing member. A lithographic printing plate precursor capable of removing the photosensitive layer in the unexposed area.


R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
R ¹⁵ to R ³² each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a cyano group or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms. The lithographic printing plate precursor as claimed in claim 11, wherein the hydrophobic binder polymer (D) is a (meth) acrylic resin or a polyurethane resin. (D) The hydrophobic binder polymer is at least one selected from the group consisting of a (meth) acrylic copolymer having a crosslinkable group in the side chain and a polyurethane resin having a crosslinkable group in the side chain. The lithographic printing plate precursor as claimed in claim 11 . The lithographic printing plate precursor as claimed in any one of claims 11 to 13 , wherein (B) the polymerization initiator is a hexaarylbiimidazole compound. The lithographic printing plate precursor as claimed in claim 14 , further comprising (E) a chain transfer agent in the photosensitive layer. The lithographic printing plate precursor as claimed in claim 15 , wherein the chain transfer agent is a thiol compound represented by the following general formula.

Here, R represents an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A represents a 5-membered or 6-membered ring having a carbon atom together with an N = CN moiety. The atomic group which forms the heterocyclic ring of A, and A may further have a substituent. The lithographic printing plate precursor as claimed in any one of claims 11 to 16 , wherein the exposed lithographic printing plate precursor is further subjected to heat treatment between exposure and development. The method for preparing a lithographic printing plate according to any one of claims 1 to 10 , wherein the developer contains a surfactant represented by the following general formula (III) or (IV).

(Wherein R _{1 to} R ₁₀ each represent a hydrogen atom or an alkyl group, l represents an integer of 1 to 3, and X ₁ and X ₂ represent a sulfonate, a monoester sulfate, a carboxylate or a phosphate, respectively. And the total number of carbon atoms in R _{1 to} R ₅ or R _{6 to} R ₁₀ is 3 or more.) The method for preparing a lithographic printing plate according to any one of claims 1 to 10 , wherein the developer contains a surfactant represented by the following general formula (V) or (VI).

(Wherein R _{1 to} R ₁₀ each represent a hydrogen atom or an alkyl group, l represents an integer of 1 to 3, and X ₁ and X ₂ represent a sulfonate, a monoester sulfate, a carboxylate or a phosphate, respectively. , Y ₁ and Y ₂ are —C _n H _2n —, —C _nm H _{2 (nm)} OC _m H _2m —, —O— (CH ₂ CH ₂ O) _n —, —O— ( CH ₂ CH ₂ CH ₂ O) _n — or —CO—NH—, where n ≧ 1, n ≧ m ≧ 0, in R _{1 to} R ₅ and Y ₁ or R _{6 to} R ₁₀ and Y ₂ (The total number of carbon atoms is 3 or more.) The method for preparing a lithographic printing plate according to any one of claims 1 to 10 , wherein the developer contains a surfactant represented by any one of the following formulas (VII) to (IX).

(In the formula (VII), Ra represents a hydrogen atom or an alkyl group, and A and B are independently a group containing an ethylene oxide group, a carboxylic acid group, or a carboxylate.
In formula (VIII), Rb and Rc independently represent a hydrogen atom or an alkyl group, C is a group containing an alkyl group or an ethylene oxide group, and D is a group containing a carboxylate anion.
In formula (IX), Rd, Re, Rf and Rg each represent a hydrogen atom or an alkyl group, and Z ⁻ is a counter anion. )