JP5189448B2 - Planographic printing plate precursor and lithographic printing plate making method - Google Patents

Description

  The present invention relates to a planographic printing plate precursor and a method for making a planographic printing plate.

Conventionally, a lithographic printing plate has a structure in which a photosensitive resin layer is provided on a support having a hydrophilic surface. As a plate-making method, usually, surface exposure (mask exposure) is performed through a lithographic film. The desired printing plate was obtained by removing the non-image area with a developer. However, computer-to-plate that directly exposes the plate surface without using a lith film by scanning the plate surface according to digitized image information with highly directional light such as laser light by recent digitization technology. (CTP) technology has been developed, and a photosensitive lithographic printing plate (lithographic printing plate precursor) adapted to the technology has been developed.
Examples of the lithographic printing plate precursor suitable for exposure with such laser light include a lithographic printing plate precursor using a polymerizable photosensitive layer. By selecting a photopolymerization initiator or a polymerization initiator system (hereinafter also simply referred to as an initiator or an initiator system), the polymerizable photosensitive layer can be easily increased in sensitivity as compared with other conventional photosensitive layers.
As the laser light source, a 405 nm or 830 nm semiconductor laser, an FD-YAG laser, or the like is used. In recent years, CTP systems equipped with a 405 nm semiconductor laser have become widespread from the viewpoint of system cost and handleability.

Patent Document 1 discloses a compound having an ethylenically unsaturated bond, M (X) _n [wherein M represents B, Al, Fe, Sn, or Zn, X represents halogen, and n represents 1 to 3. Represents an integer. And a radical generator selected from a) an onium salt, b) a triazine compound having a halogen atom, c) an iron arene complex, and d) bisimidazole. A composition is disclosed.

JP-A-9-309907

  An object of the present invention is to provide a lithographic printing plate precursor excellent in fine line loss and printing durability, and a lithographic printing plate making method.

The above-described problems of the present invention have been solved by the means described in <1> or <7> below. It describes below with <2>-<6> and <8>-<10> which are preferable embodiments.
<1> A photosensitive layer containing (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, (D) a binder polymer, and (E) a phenothiazine-based compound is provided on the support. Lithographic printing plate precursor, characterized by
<2> The lithographic printing plate precursor as described in <1> above, wherein the (E) phenothiazine compound is a compound represented by the following formula (1):

（式（１）中、Ｘ及びＹはそれぞれ独立に、ハロゲン原子、アルキル基、アルコキシ基又はアルキルチオ基を表し、ｐ及びｑはそれぞれ独立に、０〜４の整数を表す。）

(In formula (1), X and Y each independently represent a halogen atom, an alkyl group, an alkoxy group or an alkylthio group, and p and q each independently represent an integer of 0 to 4.)

<3> The lithographic printing plate precursor as described in <1> or <2> above, which has a layer containing a resin having a phosphate group and / or a phosphonic acid group between the support and the photosensitive layer.
<4> The above <1> to <3>, wherein the content of the (E) phenothiazine-based compound is 0.005 to 0.1 parts by weight with respect to 100 parts by weight of the total weight of the polymerizable compound (C). The lithographic printing plate precursor as described in any one of
<5> The above <1> to <4>, wherein the content of the (E) phenothiazine compound is 0.01 to 0.05 parts by weight with respect to 100 parts by weight of the total weight of the polymerizable compound (C). The lithographic printing plate precursor as described in any one of
<6> The lithographic printing plate precursor as described in any one of <1> to <5> above, wherein the (B) polymerization initiator is an onium salt and / or a hexaarylbiimidazole compound,
<7> An exposure process for image exposure of the lithographic printing plate precursor as described in any one of <1> to <6> above, and a development process for removing the photosensitive layer in the non-exposed area in the presence of the developer. A process for making a lithographic printing plate, comprising:
<8> The plate making method of a lithographic printing plate according to <7>, wherein the pH of the developer is 5 to 10,
<9> The plate making method of a lithographic printing plate according to the above <7> or <8>, wherein the development step is a step of simultaneously removing the photosensitive layer in the non-exposed area and gumming with one liquid,
<10> The method for making a lithographic printing plate as described in any one of <7> to <9>, wherein the water washing step is not performed before and after the development step.

  According to the present invention, it was possible to provide a lithographic printing plate precursor excellent in fine line pull-out and printing durability, and a lithographic printing plate making method.

  Hereinafter, the lithographic printing plate precursor and the lithographic printing plate making method of the present invention will be described in detail.

(Lithographic printing plate precursor)
The planographic printing plate precursor of the present invention comprises (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, (D) a binder polymer, and (E) a phenothiazine compound on a support. It has the photosensitive layer to contain.
The lithographic printing plate precursor according to the invention is a negative lithographic printing plate precursor.

When a conventional polymerization inhibitor is used in the photosensitive layer of the lithographic printing plate precursor, there is a problem that the printing durability is deteriorated, although the fine line pull-out property is excellent due to the polymerization inhibitory effect of the polymerization inhibitor.
In view of the above problems, the present inventors have conducted various studies. As a result, by including a phenothiazine-based compound in the photosensitive layer, it is possible to obtain a lithographic printing plate precursor excellent in both fine line pull-out property and printing durability. I found.

<Photosensitive layer>
The photosensitive layer (hereinafter also referred to as “image forming layer” or “recording layer”) in the lithographic printing plate precursor according to the invention comprises (A) a sensitizing dye, (B) a polymerization initiator, and (C) as basic components. It contains a polymerizable compound, (D) a binder polymer, and (E) a phenothiazine compound.

(A) Sensitizing dye The photosensitive layer in the lithographic printing plate precursor according to the invention contains a sensitizing dye.
For example, by adding a sensitizing dye having a maximum absorption at 300 to 450 nm, a sensitizing dye having a maximum absorption at 500 to 600 nm, and a sensitizing dye (infrared absorber) having a maximum absorption at 750 to 1,400 nm, High-sensitivity lithographic printing plates corresponding to a 405 nm violet laser, a 532 nm green laser, and an 830 nm IR laser, which are usually used in the industry, can be provided.
First, a sensitizing dye having a maximum absorption in the wavelength region of 350 to 450 nm will be described.
Examples of such a sensitizing dye include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, anthracenes, and the like.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 360 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following formula (IX).

（式（IX）中、Ａは置換基を有してもよい芳香族環基又はヘテロ環基を表し、Ｘは酸素原子、硫黄原子又はＮＲ₃を表す。Ｒ₁、Ｒ₂及びＲ₃は、それぞれ独立に、一価の非金属原子団を表し、ＡとＲ₁及びＲ₂とＲ₃はそれぞれ互いに結合して、脂肪族性又は芳香族性の環を形成してもよい。）

(In the formula (IX), A represents an aromatic ring group or a heterocyclic group which may have a substituent, X represents an oxygen atom, a sulfur atom or NR _3. R ₁ , R ₂ and R ₃ represent Each independently represents a monovalent non-metallic atomic group, and A and R ₁ and R ₂ and R ₃ may be bonded to each other to form an aliphatic or aromatic ring.)

Formula (IX) will be described in more detail.
R ₁ , R ₂ and R ₃ each independently represents a monovalent non-metallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, It represents a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, or a halogen atom.

Next, A in the formula (IX) will be described.
A represents an aromatic ring group or a heterocyclic group which may have a substituent. Specific examples of the aromatic ring or heterocyclic ring which may have a substituent include R ₁ in formula (IX), It includes the same as those described for R ₂ and R _3.

  As specific examples of such sensitizing dyes, compounds described in paragraphs 0047 to 0053 of JP-A-2007-58170 are preferably used.

  Furthermore, sensitizing dyes represented by the following formulas (V) to (VII) can also be used.

In formula (V), R < ¹ > -R < ¹⁴ > represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom each independently. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
In the formula (VI), R ^{15 to} R ³² 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 ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.

In formula (VII), R ¹ , R ² and R ³ each independently represent a halogen atom, an alkyl group, an aryl group, an aralkyl group, an —NR ⁴ R ⁵ group or an —OR ⁶ group, and R ⁴ , R ⁵ And R ⁶ each independently represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and k, m and n each independently represents an integer of 0 to 5.

JP 2007-171406, JP 2007-206216, JP 2007-206217, JP 2007-225701, JP 2007-225702, JP 2007-316582, JP 2007-328243. The sensitizing dyes described in each of the above publications can also be preferably used.
A preferable addition amount of the sensitizing dye in the photosensitive layer is preferably 0.05 to 30 parts by weight, more preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the total solid content of the photosensitive layer. The amount is preferably 0.2 to 10 parts by weight.

Subsequently, a sensitizing dye having a maximum absorption at 750 to 1,400 nm that is preferably used in the present invention will be described in detail. In the present invention, the “sensitizing dye having maximum absorption at 750 to 1,400 nm” is also referred to as “infrared absorber”.
The sensitizing dye used here is highly sensitive to infrared laser irradiation (exposure) and is in an electronically excited state. The electron transfer, energy transfer, heat generation (photothermal conversion function), etc., associated with the electronically excited state are the photosensitive layer. It is presumed that it acts on a polymerization initiator coexisting therein to cause a chemical change in the polymerization initiator to generate a radical. In any case, the addition of a sensitizing dye having a maximum absorption at 750 to 1,400 nm is particularly suitable for plate making directly drawn with an infrared laser beam having a wavelength of 750 to 1,400 nm. Compared with a printing plate precursor, it can exhibit high image forming properties.

  The infrared absorber is preferably a dye or pigment having an absorption maximum at a wavelength of 750 to 1,400 nm.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following formula (a).

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

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

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

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

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

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

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

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

  These infrared absorbers may be added to the same layer as other components, or another layer may be provided and added thereto.

  The content of these infrared absorbers in the photosensitive layer is 0.01 to 50% by weight with respect to the total solid content constituting the photosensitive layer, from the viewpoint of uniformity in the photosensitive layer and durability of the photosensitive layer. It is preferably 0.1 to 10% by weight, more preferably 0.5 to 10% by weight in the case of dyes, and 0.1 to 10% by weight in the case of pigments. More preferably it is.

(B) Polymerization initiator The photosensitive layer in the lithographic printing plate precursor according to the invention contains a polymerization initiator (hereinafter also referred to as “initiator compound”).
The initiator compound is a compound that undergoes an action such as electron transfer, energy transfer, and heat generation caused by the electronically excited state of the sensitizing dye to generate a chemical change and generate at least one selected from radicals, acids, and bases. It is. Hereinafter, radicals, acids, and bases generated in this way are simply referred to as active species. When the initiator compound is not present or when only the initiator compound is used alone, practically sufficient sensitivity cannot be obtained. As one mode in which a sensitizing dye and an initiator compound are used in combination, they can be used as a single compound by an appropriate chemical method (such as linking a sensitizing dye and an initiator compound through a chemical bond). It is.

  Usually, many of these initiator compounds are considered to generate active species through the initial chemical process represented by the following (1) to (3). (1) Reductive decomposition of the initiator compound based on the electron transfer reaction from the electronically excited state of the sensitizing dye to the initiator compound, (2) Electron transfer from the initiator compound to the electronically excited state of the sensitizing dye (3) decomposition of the initiator compound from the electronically excited state based on energy transfer from the electronically excited state of the sensitizing dye to the initiator compound. In many cases, it is ambiguous as to which type (1) to (3) each initiator compound belongs, but the sensitizing dye in the present invention can be combined with any of these types of initiator compounds. Shows a high sensitizing effect.

As the initiator compound in the present invention, those known to those skilled in the art can be used without limitation. Specifically, for example, trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, onium salt compounds, An iron arene complex is mentioned.
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 hexaarylbiimidazole compounds 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 ′ -Tetraphenylbiimidazole 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5 Examples include 5′-tetraphenylbiimidazole.
The hexaarylbiimidazole compound is particularly preferably used in combination with a sensitizing dye having a maximum absorption at 300 to 450 nm.

  The onium salt suitably used in the present invention (in the present invention, functions as an ionic polymerization initiator, not as an acid generator) is represented by the following formulas (RI-I) to (RI-III). Onium salt.

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and a carbon number. 1-12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C1-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamide groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyl groups And a thioaryl group having 1 to 12 carbon atoms. Z ₁₁ ^- represents a monovalent anion, specifically a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, a sulfate ion Can be mentioned. Of these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable from the viewpoint of stability.

In formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include 1 to 1 carbon atoms. 12 alkyl groups, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, Halogen atom, C1-C12 alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 1 to 12 carbon atoms.
Z ₂₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of stability and reactivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl group having 20 or less carbon atoms which may have 1 to 6 substituents. Represents. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms.
Z ₃₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.
The onium salt is particularly preferably used in combination with an infrared absorber having a maximum absorption at 750 to 1,400 nm.

  As other polymerization initiators, JP-A No. 2007-171406, JP-A No. 2007-206216, JP-A No. 2007-206217, JP-A No. 2007-225701, JP-A No. 2007-225702, JP-A No. 2007-316582, The polymerization initiators described in JP-A-2007-328243 can be preferably used.

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 weight, more preferably 0.1 to 15% by weight, based on the total solid content of the photosensitive layer. Preferably, it is 1.0 to 10% by weight.

(C) Polymerizable compound The polymerizable compound used in the photosensitive layer in the invention is a compound having at least one ethylenically unsaturated double bond, and has at least one terminal ethylenically unsaturated bond, preferably two. It is selected from the compounds having the above. Such a compound group is widely known in the industrial field, and in the present invention, these can be used without any particular limitation. These have chemical forms such as monomers, prepolymers, that is, dimers, trimers and oligomers, copolymers thereof, or mixtures thereof.
Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used.
Further, addition reaction products of unsaturated carboxylic acid esters or amides having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group and the like with monofunctional or polyfunctional isocyanates or epoxies, 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 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 ester monomer of the polyhydric alcohol compound and the unsaturated carboxylic acid include the following.
Acrylic esters include ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylol Methylolpropane 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) modified triacrylate, polyester acrylate oligomer and the like.

  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 and the like.

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 polyvalent amine compounds and unsaturated carboxylic acids include methylene bisacrylamide, methylene bismethacrylamide, 1,6-hexamethylene bisacrylamide, 1,6-hexamethylene bismethacrylamide, Examples include diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.
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 vinyl urethane compound containing two or more vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following formula (A) to a polyisocyanate compound having two or more isocyanate groups. Can be mentioned.

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (A)
(In the formula, R ⁴ and R ⁵ each independently represents a hydrogen atom or a methyl group.)

  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. In addition, 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 high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher polymerizable compound is preferable.
In order to increase the strength of the image area, that is, the cured film, a tri- or higher functional polymerizable compound is preferable, and furthermore, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrene type). It is also effective to adjust both sensitivity and strength by using a compound or a vinyl ether compound).
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 using two or more of them together. In addition, a specific structure can be selected for the purpose of improving the adhesion to the support or the protective layer described later. In addition, the usage method 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 configuration and coating method such as undercoating and overcoating can be considered.

  The content of the polymerizable compound in the photosensitive layer is preferably 5 to 75% by weight, more preferably 25 to 70% by weight, and more preferably 30 to 60% by weight with respect to the total solid content of the photosensitive layer. More preferably.

(D) Binder polymer The photosensitive layer in the lithographic printing plate precursor according to the invention contains a binder polymer.
The chemical structure of the binder polymer that can be used in the present invention is not particularly limited, but is preferably an organic polymer having an acid group from the viewpoint of solubility in a weakly alkaline processing liquid, that is, developability, and particularly carboxylic acid or its carboxylic acid. An organic polymer containing a salt is more preferable.
Examples of the binder polymer that can be used in the present invention include carboxylic acid-containing alkaline water-soluble or swellable organic polymers.
Examples of such organic polymers include addition polymers having a carboxylic acid group in the side chain, such as JP-A-59-44615, JP-B-54-34327, JP-B-58-12777, and JP-B-54-25957. , JP-A-54-92723, JP-A-59-53836, JP-A-59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer, itacon Acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers and the like are useful. As the binder polymer, a copolymer containing a monomer unit derived from a (meth) acrylic acid ester containing a carboxylic acid (salt) group is preferable.
Also useful are acidic cellulose derivatives having a carboxylic acid group in the side chain and those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxy group.
Further, Japanese Patent Publication No. 7-120040, Japanese Patent Publication No. 7-120041, Japanese Patent Publication No. 7-120042, Japanese Patent Publication No. 8-12424, Japanese Patent Publication No. 63-287944, Japanese Patent Publication No. 63-287947, Japanese Patent Publication No. Hei 1 Polyurethane resins described in JP-A Nos. 271741 and 11-352691 are also useful as alkaline water-soluble or swellable binders.
As the binder polymer used in the present invention, an acrylic resin, a methacrylic resin, or a urethane resin is preferably used.

An example of a material suitable as a binder polymer that can be used in the present invention is a copolymer having a monomer unit containing the following (a) carboxylic acid (including a salt thereof) and (b) a monomer unit imparting radical crosslinkability. It is a polymer.
(A) Although it does not specifically limit as a monomer unit containing carboxylic acid, The following structure is used preferably.

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

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

More specifically, the linking group represented by R ² in formula (I) is alkylene, substituted alkylene, arylene, substituted arylene, or a hydrogen atom on any carbon atom constituting these groups (n + 1). ) Having a valent group, and those having a structure in which a plurality of these groups are linked by amide bonds or ester bonds are preferred. In particular, those having 5 to 10 atoms constituting the main skeleton of the linking group are preferable. Structurally, the structure is a chain structure having an ester bond in the structure, or a cyclic structure as described above. What has is preferable.
Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), carbonization. Examples thereof include a hydrogen group (alkyl group, aryl group, alkenyl group, alkynyl group), alkoxy group, and aryloxy group.
A in formula (I) is preferably an oxygen atom or —NH— because synthesis is easy.
N in the formula (I) represents an integer of 1 to 5, and is preferably 1 in terms of printing durability.
(A) Specific examples of the monomer unit imparting alkali solubility include compounds having the structures shown in (a-1) to (a-12) shown below.
When the total number of monomer units is 100, the content of the monomer containing (a) carboxylic acid is preferably 5 to 50 units, more preferably 5 to 25 units, More preferably, it is 15 units.

  Specific examples of the monomer unit that imparts (b) radical crosslinkability include the structures shown in the following (b-1) to (b-11).

  The content of the monomer unit that imparts (b) radical crosslinkability, when the total number of monomer units is 100, is preferably 5 to 90 units, more preferably 20 to 85 units, More preferably, it is 40 to 80 units.

The binder polymer that can be used in the present invention is a copolymer of monomer units derived from an ethylenically unsaturated compound that contains neither (a) a monomer unit that imparts alkali solubility nor (b) a monomer unit that imparts radical crosslinkability. You may have as a component.
As such a monomer unit, a monomer unit derived from (meth) acrylic acid ester or (meth) acrylic acid amide is preferable. In particular, a monomer unit derived from an amide group (meth) acrylic acid amide described in paragraphs 0061 to 0084 of JP-A-2007-272134 is preferably used. The content of this monomer is preferably 5 to 50 units, more preferably 5 to 35 units, even more preferably 5 to 25 units, when the total number of monomer units is 100. .

  In the photosensitive layer according to the invention, a urethane resin having a crosslinkable group in the side chain can be used as the binder polymer in addition to the addition polymer having the above-mentioned combination of monomer units. Here, the crosslinkable group is a group capable of crosslinking the binder polymer by a chemical reaction that occurs in the image forming layer when the lithographic printing plate precursor is exposed. The chemical structure is not particularly limited as long as it is a group having such a function. Examples of the functional group capable of addition polymerization include cyclic ether groups such as an ethylenically unsaturated group and an epoxy group / oxetanyl group. Moreover, the functional group which can become a radical by light irradiation may be sufficient, As such a crosslinkable group, a thiol group, a halogen atom, an onium salt structure etc. are mentioned, for example. Among these, an ethylenically unsaturated group is preferable. Moreover, the functional group described in Paragraphs 0130 to 0139 of Unexamined-Japanese-Patent No. 2007-17948 can be illustrated.

The polyurethane resin having a crosslinkable group in the above side chain not only functions as a film-forming agent for the photosensitive layer, but also needs to be dissolved in an alkaline processing solution, so that it may be soluble or swellable in alkaline water. Required. Therefore, in addition to the crosslinkable group, the side chain has an alkali water-soluble group such as a carboxyl group (including salts thereof). Polyurethane resin can suppress the development damage of the exposed area without lowering the developability of the unexposed area even if the acid value of the photosensitive layer is low, and can have both good stain resistance and high printing durability. This is preferable.
The polyurethane resin having a crosslinkable group in the side chain will be described in more detail below.

  The polyurethane resin having a crosslinkable group in the side chain particularly preferably used in the present invention comprises (i) a diisocyanate compound, (ii) a diol compound having a carboxyl group, (iii) a diisocyanate compound having a crosslinkable group, and if necessary. (Iv) It can be obtained by polyaddition reaction of a diol compound having no carboxyl group and (v) a compound having an amino group.

  Examples of the compounds (i), (ii) and (iii) include formulas (4) to (10) and specific examples described in paragraphs 0142 to 0167 of JP-A No. 2007-17948.

  Here, as a method for introducing a crosslinkable group into the side chain of the polyurethane resin, a method using a diisocyanate compound containing a crosslinkable group in the side chain as a raw material for producing the polyurethane resin is suitable. A diisocyanate compound obtained by addition reaction of a triisocyanate compound and a monofunctional alcohol having a crosslinkable group or 1 equivalent of a monofunctional amine compound, having a crosslinkable group in the side chain, Examples thereof include the compounds described in paragraphs 0179 to 0178 of JP 2007-17948.

(Iv) Diol compound having no carboxyl group As a method for introducing an unsaturated group into the side chain of the polyurethane resin, a method using a diol compound containing an unsaturated group in the side chain as a raw material for producing the polyurethane resin is also employed. it can. Such diol compounds include, for example, those commercially available such as trimethylolpropane monoallyl ether, halogenated diol compounds, triol compounds, aminodiol compounds, carboxylic acids containing unsaturated groups, acids Also included are compounds produced by reaction with chlorides, isocyanates, alcohols, amines, thiols, alkyl halide compounds. Specific examples of these compounds include general formula (A ′), formulas (a) to (e), formulas (11) to (22) described in paragraphs 0180 to 0225 of JP-A No. 2007-17948, and Specific compounds may be mentioned.

(V) A compound having an amino group As a binder polymer that can be used in an image forming layer, in the production of a polyurethane resin, an amino group-containing compound is further combined and reacted with a diisocyanate compound to form a urea structure and incorporated into the structure of the polyurethane resin. But you can. Examples of the amino group-containing compound include Formula (31) and Formula (32) and specific compounds described in paragraphs 0227 to 0230 of JP-A No. 2007-17948.

  The binder polymer that can be used in the present invention includes a carboxyl group as described in JP-A-2003-270775, in addition to the polyurethane resin obtained by introducing a crosslinkable group into the side chain during polyurethane synthesis. The polyurethane resin obtained by introduce | transducing a crosslinkable group by polymer reaction to the polyurethane which has is also illustrated.

  In the present invention, among the monomers having a melting point of 45 ° C. or higher and the urethane resin having the crosslinkable group, Tg is preferably 45 ° C. or higher, more preferably 50 ° C. or higher. Combinations are particularly preferably used. Specific examples of such urethane resins are shown below, but the present invention is not limited thereto.

  In order to maintain the developability of the photosensitive layer, the binder polymer used preferably has an appropriate molecular weight, more preferably a weight average molecular weight of 5,000 to 300,000, and 20,000 to More preferably, it is 150,000.

  These binder polymers can be contained in an arbitrary amount in the photosensitive layer, but the content of the binder polymer in the photosensitive layer is preferably 10 to 90% by weight, and 30 to 80% by weight. More preferably.

(E) Phenothiazine-based compound The photosensitive layer in the lithographic printing plate precursor according to the invention contains a phenothiazine-based compound.
The phenothiazine-based compound that can be used in the present invention is not particularly limited as long as it is a compound having a phenothiazine ring, but is preferably a compound in which the group on the nitrogen atom of the phenothiazine ring is a hydrogen atom. The phenothiazine-based compound is preferably a compound having at least one group other than a hydrogen atom on the phenothiazine ring.
Moreover, as a phenothiazine type compound, the compound represented by following formula (1) is more preferable.

（式（１）中、Ｘ及びＹはそれぞれ独立に、ハロゲン原子、アルキル基、アルコキシ基又はアルキルチオ基を表し、ｐ及びｑはそれぞれ独立に、０〜４の整数を表す。）

(In formula (1), X and Y each independently represent a halogen atom, an alkyl group, an alkoxy group or an alkylthio group, and p and q each independently represent an integer of 0 to 4.)

X and Y in Formula (1) can be bonded at any position on the aromatic ring of the phenothiazine ring.
X and Y each independently represent a halogen atom, an alkyl group, an alkoxy group or an alkylthio group, preferably a halogen atom, an alkyl group or an alkoxy group, and a fluorine atom, a chlorine atom, or a carbon number of 1 to 4 It is more preferable that it is an alkyl group or a C1-C4 alkoxy group.
The alkyl group in X and Y, the alkyl group in the alkoxy group, and the alkyl group in the alkylthio group may have a substituent. The number of the substituents may be one, two or more, or not. Further, the substituent may be further substituted with a substituent.
Examples of the substituent include an alkyl group, an aryl group, a halogen atom, a hydroxy group, an alkoxy group, an aryloxy group, an alkylthio group, and an arylthio group.
P and q in Formula (1) each independently represent an integer of 0 to 4, preferably 0 to 2, more preferably 0 or 1. Further, in p and q, it is more preferable that both p and q are 0, and one of p and q is 1 and the other is 0.

Specific examples of the phenothiazine compound include phenothiazine, 10-methylphenothiazine, 2-methylphenothiazine, 2-chlorophenothiazine, 2-trifluoromethylphenothiazine, 2-methoxyphenothiazine, and bis (α-methylbenzyl) phenothiazine. 3,7-dioctylphenothiazine, bis (α, α-dimethylbenzyl) phenothiazine, and the like. Among these, phenothiazine is particularly preferable.
Only one type of phenothiazine-based compound may be contained in the photosensitive layer, or two or more types may be contained.

  The content of the phenothiazine-based compound is preferably 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the total weight of the polymerizable compound (C), and 0.005 to 0.1 parts by weight. More preferably, it is 0.01 to 0.05 part by weight. Within the above range, fine line pull-out and printing durability can be achieved at a more excellent level.

(F) Microcapsule In the present invention, as a method for causing the photosensitive layer to contain the photosensitive layer constituents and other constituents described later, for example, JP-A-2001-277740 and JP-A-2001-277742 are described. As described above, a part of the components can be encapsulated in microcapsules and added to the photosensitive layer. In that case, each component can be contained in the microcapsule and outside at any ratio.

As a method for microencapsulating the photosensitive layer constituent components, known methods can be applied.
As a method for producing microcapsules, for example, a method using coacervation found in U.S. Pat. Nos. 2,800,047 and 2,800,498, each specification of U.S. Pat. No. 3,287,154, Japanese Patent Publication No. 38-19574, 42-446 by the interfacial polymerization method, U.S. Pat. Nos. 3,418,250 and 3,660,304, by precipitation of polymers, and U.S. Pat. No. 3,796,669. A method using a polyol wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and urea-formaldehyde found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. System or urea formaldehyde-resorcino A method using a system wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose found 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 preferred microcapsule wall that can be used in the present invention has a three-dimensional cross-linking and 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, more preferably 0.05 to 2.0 μm, and still more preferably 0.10 to 1.0 μm. In the above range, good resolution and stability over time can be obtained.

(G) Other photosensitive layer components The photosensitive layer in the lithographic printing plate precursor according to the invention may further contain various additives as required.
Additives include surfactants for improving developability and improving the surface of the coating, hydrophilic polymers for improving developability and improving the dispersion stability of microcapsules, and visual and non-image areas. In order to prevent polymerization inhibition due to oxygen, polymerization inhibitors other than phenothiazine-based compounds to prevent unnecessary thermal polymerization of radically polymerizable compounds during production or storage of photosensitive layers Higher fat derivatives, inorganic fine particles for improving the cured film strength of the image area, hydrophilic low molecular weight compounds for improving the developability, co-sensitizers and chain transfer agents for improving the sensitivity, plasticity for improving the plasticity An agent or the like can be added. Any of these compounds can be used, for example, JP 2007-171406, JP 2007-206216, JP 2007-206217, JP 2007-225701, JP 2007-225702, The compounds described in JP-A 2007-316582 and JP-A 2007-328243 can be used.

  As the chain transfer agent, for example, a compound group having SH, PH, SiH, GeH in the molecule is used. These can generate hydrogen by donating hydrogen to a low-activity radical species to generate radicals, or after being oxidized and deprotonated.

  In particular, thiol compounds (for example, 2-mercaptobenzimidazoles, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 3-mercaptotriazoles, 5-mercaptotetrazoles, etc.) are chain-transferred to the photosensitive layer. It can be preferably used as an agent.

  Among these, a thiol compound represented by the following formula (S) is particularly preferably used. By using this thiol compound as a chain transfer agent, avoiding a decrease in sensitivity due to evaporation from the photosensitive layer or diffusion to other layers, excellent storage stability, and high sensitivity and high durability lithographic printing plate precursor can get.

  In formula (S), 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.

<Formation of photosensitive layer>
The photosensitive layer in the lithographic printing plate precursor according to the invention can be 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 weight.
The photosensitive layer may 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.

Moreover, although the photosensitive layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, it is preferably 0.3 to 3.0 g / m ² . Within the above 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>
In the lithographic printing plate precursor according to the invention, a protective layer (oxygen blocking layer) is preferably provided on the photosensitive layer in order to block diffusion and penetration of oxygen which hinders the polymerization reaction during exposure.
The protective layer used in the present invention preferably has an oxygen permeability A at 25 ° C. and 1 atm of 1.0 ≦ A ≦ 20 (mL / m ² · day). When the oxygen permeability A is 1.0 (mL / m ² · day) or more, unnecessary polymerization reaction during production and raw storage can be suppressed, and unnecessary fogging and image line weight increase during image exposure. It is possible to suppress the occurrence of a problem that occurs. Moreover, when the oxygen permeability A is 20 (mL / m ² · day) or less, the sensitivity is excellent. The oxygen permeability A is more preferably 1.5 ≦ A ≦ 12 (mL / m ² · day), and is in the range of 2.0 ≦ A ≦ 10.0 (mL / m ² · day). More preferably it is.
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 the 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 (PVA), vinyl alcohol / vinyl phthalate copolymer, acetic acid Water / soluble polymers such as vinyl / vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, polyacrylamide, etc. These can be used alone or in combination. 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 2,400.
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. These can be used alone or in combination. As a preferable embodiment, the content of polyvinyl alcohol in the protective layer is preferably 20 to 95% by weight, and more preferably 30 to 90% by weight.

  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 and 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 viewpoints of oxygen barrier properties, development removability, and the content in the protective layer is preferably 3.5 to 80% by weight. 10 to 60% by weight, more preferably 15 to 30% by weight.

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) is preferably in the range of 2,000 to 10 million, more preferably in the range of 20,000 to 3 million.

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added to the (co) polymer in an amount corresponding to several weight% to give flexibility, and sodium alkyl sulfate, alkyl sulfone Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer % By weight 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 adhesion can be obtained by mixing 20 to 60% by weight 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 of 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 plate-like shape. For example, the following formula A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
(In the formula, A represents any of K, Na, and Ca, B and C represent any of Fe (II), Fe (III), Mn, Al, Mg, and V, and D represents Si or Al. Represents.)
And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by 3MgO.4SiO.H ₂ O.
In the present invention, among the inorganic layered compounds, fluorine-based swellable synthetic mica, which is a synthetic inorganic layered compound, is particularly useful.
The aspect ratio of the inorganic stratiform compound is preferably 20 or more, more preferably 100 or more, and further preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured from, for example, a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  The average major axis of the inorganic layered compound is preferably 0.3 to 20 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to 5 μm. The average thickness of the particles is preferably 0.1 μm or less, more preferably 0.05 μm or less, and further preferably 0.01 μm or less. For example, the size of the swellable synthetic mica that is a representative compound among the inorganic layered compounds is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When particles of inorganic layered compounds having 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 of the layer is prevented, and even when stored for a long time under a high humidity condition, the storage stability is excellent without a decrease in image forming property in the lithographic printing plate precursor due to a change in humidity.

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

  The dispersion method of the inorganic stratiform compound used for the protective layer is disclosed in JP 2007-171406 A, JP 2007-206216 A, JP 2007-206217 A, JP 2007-225701 A, and JP 2007-225702 A. The methods described in Japanese Patent Laid-Open No. 2007-316582 and Japanese Patent Laid-Open No. 2007-328243 are used.

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 that can be 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 support, but is preferably a 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.), paper or plastic film on which the metal is laminated or deposited. A preferable support includes 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 foreign elements, or a plastic laminated on a thin film of aluminum or aluminum alloy. Examples of the foreign element contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by weight 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, and therefore 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 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and further preferably 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 is 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 cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by weight solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm 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 the above range, good printing durability and good scratch resistance of the non-image area of the planographic printing plate can be obtained.

  As a support that can be 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 further improvement in adhesiveness to the upper layer, hydrophilicity, resistance to contamination, heat insulation, etc. Therefore, if necessary, the micropore enlargement treatment, the micropore sealing treatment, and the hydrophilicity described in JP 2001-253181 A and JP 2001-322365 A A surface hydrophilization treatment or the like immersed in an aqueous solution containing a compound can be appropriately selected and performed. Of course, the enlargement process and the sealing process 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.
Among these, a sealing treatment with an aqueous solution containing an inorganic fluorine compound, a sealing treatment with water vapor, and a sealing treatment with hot water are preferable.

  The hydrophilization treatment is described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are such alkali metal silicate methods. 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, it is preferable to apply a hydrophilic layer to make the surface hydrophilic.
The hydrophilic layer is at least selected from the group consisting of beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metals described in JP-A-2001-199175. Obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 or a hydrophilic layer formed by coating a coating solution containing one elemental oxide or hydroxide colloid. A hydrophilic layer having an organic 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 metal oxide Hydrophilic film composed of an inorganic thin film having a surface containing It is preferred. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body, 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 to 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 the above range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the photosensitive layer is provided on the undercoat layer. The undercoat layer reinforces the adhesion between the support and the photosensitive layer in the exposed area, and easily peels the photosensitive layer from the support in the unexposed area, thereby improving the developability.
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. Particularly preferred compounds include compounds having a polymerizable group such as a methacryl group and an allyl group and a support-adsorptive group such as a sulfonic acid group, a phosphoric acid group and a phosphoric acid ester. A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound.
The undercoat layer preferably also contains a resin having a phosphate group and / or a phosphonic acid group. In particular, it preferably has a resin having a phosphonic acid group, and an undercoat layer formed by treatment with the polyvinylphosphonic acid mentioned in the hydrophilization treatment of the support is preferably used.
The coating amount (solid content) of the undercoat layer is preferably 0.1-100 mg / m ^2, 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 backcoat layer can be provided on the back surface of the support, if necessary.
Examples of the back coat layer include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organic metal compounds or inorganic metal compounds described in JP-A-6-35174, and the like. Preferable examples include a coating layer made of a metal oxide. 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 of lithographic printing plate)
Next, the plate making method of the planographic printing plate of the present invention, that is, the plate making process will be described.
The plate making method of the lithographic printing plate of the present invention comprises an exposure step of image exposure of the lithographic printing plate precursor of the present invention, and a development step of removing the photosensitive layer in the non-exposed area in the presence of a developer. To do.
In the lithographic printing plate making method of the present invention, the developing step is preferably a step in which the photosensitive layer in the non-exposed area is removed and gummed simultaneously with one liquid.
Furthermore, it is preferable that the lithographic printing plate making method of the present invention is a production method in which a water washing step is not performed before and after the developing step.
The developer preferably contains carbonate ions, hydrogen carbonate ions, and water-soluble polymer compounds. After the lithographic printing plate precursor of the present invention is image-exposed and then processed with the developer, the photosensitive layer can be developed and gummed in one bath. Further, in the case of a lithographic printing plate precursor provided with a protective layer, removal of the protective layer, development of the photosensitive layer, and gumming of the obtained image can be performed in one bath.
Here, the development processing of the photosensitive layer means that an image corresponding to the exposed portion is formed by removing the non-exposed portion of the photosensitive layer with the above processing solution.

  In the present invention, in the plate making process for producing a lithographic printing plate from a lithographic printing plate precursor, the entire surface of the lithographic printing plate precursor may be heated before exposure, during exposure, and between exposure and development, as necessary. . By such heating, an image forming reaction in the image forming layer is promoted, and the advantages of improved sensitivity, improved printing durability, and stabilized sensitivity are obtained. Further, for the purpose of improving the image strength and printing durability, it is also effective to post-heat the image obtained by development or to expose the entire surface. Usually, heating before development is preferably performed under mild conditions of 150 ° C. or less. Stronger conditions are used for heating after development. A temperature range of 200-500 ° C is preferred.

<Exposure process>
The exposure process for exposing the planographic printing plate precursor imagewise can be roughly divided into two. One is image exposure performed through a transparent original image having a line image, halftone dot image, and the like, and the other is image exposure performed by scanning a laser light source based on digital data.
As the lithographic printing plate precursor 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 because of the relationship between the sensitivity of the lithographic printing plate precursor (hereinafter also referred to as “original plate”) and the plate making time.
A single-beam to triple-beam exposure apparatus that uses one or more gas lasers or solid-state laser light sources so that the internal drum system produces a semiconductor laser with a total output of 20 mW or more.
A multi-beam (1 to 10) exposure apparatus using one or more semiconductor lasers, gas lasers or solid-state lasers so that the total output is 20 mW or more in a flat bed system.
A multi-beam (1 to 9) exposure apparatus that uses one or more semiconductor lasers, gas lasers, or solid-state lasers to achieve a total output of 20 mW or more in the external drum system.
A multi-beam (10 or more) exposure apparatus that uses one or more semiconductor lasers or solid state lasers so that the total output is 20 mW or more in the external drum system.

In the laser direct drawing type lithographic printing plate precursor as described above, generally, the sensitivity of the original plate X (J / cm ² ), the exposure area S (cm ² ) of the original plate, the power q (W) of one laser light source, the number of lasers Formula (eq 1) is established between n and the total exposure time t (s).
X · S = n · q · t (eq 1)

i) Internal drum (single beam) method:
Equation (eq 2) is generally established between the laser rotation speed f (radians / s), the original sub-scanning length Lx (cm), the resolution Z (dots / cm), and the total exposure time t (s). .
f · Z · t = Lx (eq 2)

ii) External drum (multi-beam) method:
A general formula between the drum rotation speed F (radians / s), the original sub-scanning length Lx (cm), the resolution Z (dots / cm), the total exposure time t (s), and the number of beams (n) eq 3) holds.
F.Z.n.t = Lx (eq 3)

iii) Flat head (multi-beam) method:
It is generally between the polygon mirror rotation speed H (radians / s), the original sub-scanning length Lx (cm), resolution Z (dots / cm), total exposure time t (s), and number of beams (n). Equation (eq 4) holds.
H.Z.n.t = Lx (eq 4)

Resolution required for an actual printing plate precursor (2,560 dpi), plate size (A1 / B1, sub-scanning length 42 inches), exposure conditions of about 20 sheets / hour and photosensitive characteristics of the planographic printing plate precursor according to the present invention By substituting (photosensitive wavelength, sensitivity: about 0.1 mJ / cm ² ) into the above formula, the lithographic printing plate precursor according to the present invention can be combined with a multi-beam exposure method using a laser having a total output of 20 mW or more. It can be seen that it is particularly preferable. 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.

Although the infrared laser which can be used for this invention is not specifically limited, The solid laser and semiconductor laser which radiate | emit infrared rays with a wavelength of 750-1,200 nm are mentioned suitably. The output of the infrared laser is preferably 100 mW or more. In order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure time per pixel is preferably within 20 μsec. Moreover, it is preferable that irradiation energy amount is 10-300 mJ / cm < ² >. As the light source, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 5 to 30 mW) is suitable in terms of wavelength characteristics and cost.

  Further, the photosensitive layer component of the lithographic printing plate precursor according to the invention can be made soluble in neutral water or weak alkaline water by using a highly water-soluble component. After loading on the printing press, a system such as exposure-development can be performed on the press.

<Developer>
The developer (also referred to as “processing solution”) that can be used in the plate making method of the lithographic printing plate of the present invention is not particularly limited, and examples thereof include known developers, but carbonate ions, bicarbonate ions, and water An aqueous solution containing a functional polymer compound is preferred. The presence of carbonate ions and hydrogen carbonate ions exerts a pH buffering effect, and even when a developer is used for a long period of time, fluctuations in pH can be suppressed, and development deterioration due to pH fluctuations, development residue generation, and the like can be suppressed. Carbonate and bicarbonate ions may be added to the developer, but carbonate and bicarbonate ions are generated by adjusting the pH after adding carbonate or bicarbonate. You may let them. When carbonate or bicarbonate is used, it is not particularly limited, but an alkali metal salt is preferable. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. These may be used alone or in combination of two or more.

Although there is no restriction | limiting in particular as pH of the said developing solution, It is preferable that it is 2-11, It is more preferable that it is 4-10.8, It is further more preferable that it is 4.5-10, 5-10 Particularly preferred is 5 or more and less than 10.
Moreover, as pH in the developing solution containing a carbonate ion and hydrogencarbonate ion, it is preferable that it is the range of 8.5-10.8, It is more preferable that it is pH9.0-10.5, pH9.5- Particularly preferred is 10.3. Within this pH range, the developability of the non-image area does not deteriorate, and the processing capability does not vary due to the influence of carbon dioxide in the air, which is preferable.

  The developer used in the lithographic printing plate making method of the present invention is preferably an aqueous solution having a pH of 8.5 to 10.5 containing an alkali metal carbonate, a hydrogen carbonate and a water-soluble resin. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. These may be used alone or in combination of two or more.

  The total amount of the carbonate and bicarbonate is preferably 1 to 20% by weight, more preferably 3 to 15% by weight, and most preferably 4 to 12% by weight based on the weight of the developer. When this concentration is 1% by weight or more, developability and processing capacity do not decrease, and when it is 20% by weight or less, it becomes difficult to produce precipitates and crystals, and further, it becomes difficult to gel during neutralization in the waste liquid. Does not interfere with waste liquid treatment.

Further, for the purpose of assisting the fine adjustment of the alkali concentration and the dissolution of the photosensitive layer, another alkali agent such as an organic alkali agent may be supplementarily used together.
Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These alkali agents are used alone or in combination of two or more.

  Examples of water-soluble polymer compounds that can be used in the present invention include soybean polysaccharides, modified starches, gum arabic, dextrin, fiber derivatives (such as carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol. And derivatives thereof, polyvinylpyrrolidone, polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like.

  As said soybean polysaccharide, what is known conventionally can be used, 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 weight aqueous solution is in the range of 10 to 100 mPa / sec.

  As said modified starch, what is shown by following formula (III) is preferable. As the starch represented by the formula (III), any starch such as corn, potato, tapioca, rice and wheat can be used. These starch modifications can be made by, for example, a method of decomposing within 5 to 30 glucose residues per molecule with an acid or enzyme, and further adding oxypropylene in an alkali.

（式中、エーテル化度（置換度）はグルコース単位当たり０．０５〜１．２の範囲で、ｎは３〜３０の整数を示し、ｍは１〜３の整数を示す。）

(In the formula, the degree of etherification (degree of substitution) is in the range of 0.05 to 1.2 per glucose unit, n represents an integer of 3 to 30, and m represents an integer of 1 to 3.)

  Among the water-soluble polymer compounds, soybean polysaccharides, modified starch, gum arabic, dextrin, carboxymethyl cellulose, polyvinyl alcohol and the like are particularly preferable.

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

The treatment liquid may contain a surfactant (anionic, nonionic, cationic, etc.).
Examples of the anionic surfactant that can be 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, and branched alkyl benzene sulfonic acid. Salts, alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfone Acid salts, sulfated castor oil, sulfated beef tallow oil, sulfate esters of fatty acid alkyl esters, alkyl sulfate esters, polyoxyethylene alkyl ether sulfate esters, Fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates Saponification product of styrene-maleic anhydride copolymer, saponification product 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.

  The cationic surfactant that can be 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.

  Nonionic surfactants that can be 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 alkyl. Amine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, oil and fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. Polyol alcohol fatty acid ester of glycerol, fatty acid ester of pentaerythritol, sorbitol and soy Fatty acid esters of the tail, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.

  These nonionic surfactants may be used alone or in combination 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.

From the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the developer preferably has an HLB (Hydrophile-Lipophile Balance) value of 6 or more, preferably 8 or more. It is more preferable. Furthermore, the ratio of the nonionic surfactant contained in the treatment liquid is preferably 0.01 to 10% by weight, and more preferably 0.01 to 5% by weight. Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.
These surfactants can be used alone or in combination. Further, the content of these surfactants in the developer is preferably in the range of 0.1 to 20% by weight in terms of active ingredients.

  In addition to the above, the developer that can be used in the present invention may contain a wetting agent, preservative, chelate compound, antifoaming agent, organic acid, organic solvent, inorganic acid, inorganic salt, and the like.

  As the wetting agent, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, diglycerin and the like are preferably used. These wetting agents may be used alone or in combination of two or more. Generally, the wetting agent is used in an amount of 0.1 to 5% by weight based on the total weight of the processing solution.

Examples of preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzoisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, and benztriazole derivatives. Amiding anidine derivatives, quaternary ammonium salts, derivatives of pyridine, quinoline, guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3-diol, 1 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.
The addition amount of the preservative is an amount that exerts stability against bacteria, molds, yeasts, etc., and varies depending on the types of bacteria, molds, yeasts, but is 0. The range of 01 to 4% by weight is preferable, and it is preferable to use two or more preservatives in combination so as to be effective against various molds and sterilization.

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.
These chelating agents are selected so that they exist stably in the treatment liquid composition and do not impair the printability. The addition amount is preferably 0.001 to 1.0% by weight with respect to the treatment liquid at the time of use.

As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, nonionic HLB 5 or less compound can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used.
The content of the antifoaming agent is preferably in the range of 0.001 to 1.0% by weight with respect to the treatment liquid at the time of use.

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.
The content of the organic acid is preferably 0.01 to 0.5% by weight based on the total weight of the treatment liquid.

  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). , Xylene, etc.), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, tricrene, 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 properties, the concentration of the solvent is preferably less than 40% by weight.

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 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 content of the inorganic salt is preferably 0.01 to 0.5% by weight based on the total weight of the treatment liquid.

<Development process>
The development step in the lithographic printing plate making method of the present invention will be described in detail.
In a normal development process, the protective layer is removed by a pre-water washing process, then development is performed with an alkaline developer, alkali is removed by a post-water washing process, gumming is performed in a gumming process, and drying is performed in a drying process.
In the present invention, development and gumming are preferably performed with a single solution.
“Gum-drawing” in the present invention means a plate surface hydrophilization treatment with a surfactant and / or a water-soluble polymer compound. That is, it is preferable that a separate gumming process is not performed after the development and gumming processes.
In the present invention, the developer preferably contains a water-soluble polymer compound. Moreover, it is preferable to perform a drying process after developing and gumming by one liquid, without performing a post-water washing process.
Furthermore, it is preferable to simultaneously perform removal of the protective layer, development processing, and gumming with one liquid without performing a pre-water washing step. Moreover, it is preferable to dry after removing a surplus developing solution using a squeeze roller after a development process and gumming.
The development of the lithographic printing plate precursor according to the invention is carried out in accordance with a conventional method at a temperature of 0 to 60 ° C., preferably about 15 to about 40 ° C., for example, by immersing the exposed lithographic printing plate precursor in a developer and brushing It can be performed by rubbing with, for example. Further, when developing using an automatic developing machine, the developing solution becomes fatigued due to an increase in the processing amount. Therefore, it is preferable to restore the processing capability using a replenishing solution or a fresh developing solution.

  The hydrophilic support in the present invention can be subjected to a mechanical surface roughening treatment as described in Example 1 described later. An apparatus as shown in FIG. 2 can be used for this mechanical roughening treatment.

The planographic printing plate precursor was developed using an automatic development processing apparatus illustrated in FIG.
Here, the “development process” means a composite process including one or more processes selected from the group consisting of removal of the protective layer, gumming and drying in addition to the development of the image forming layer. .
The used processing liquid is illustrated in the Examples. The automatic developing apparatus is an automatic processor having two rotating brush rolls 1. As the rotating brush roll 1, a brush roll having an outer diameter of 90 mm in which fibers made of polybutylene terephthalate (hair diameter: 200 μm, hair length: 17 mm) is used for the first rotating brush roll 1 is the same as the conveying direction. The direction was 200 revolutions per minute (peripheral speed of brush tip 0.94 m / sec). The second rotating brush roll 1 uses a brush roll having an outer diameter of 60 mm in which fibers made of polybutylene terephthalate (hair diameter: 200 μm, hair length: 17 mm) are used. It was rotated 200 times (peripheral speed of the brush tip 0.63 m / sec). The exposed lithographic printing plate precursor 12 is conveyed between the three pairs of conveying rolls 3 so that the lithographic printing plate precursor 12 passes between the rotating brush roll 1 and the receiving roll 2 facing it. In the direction from the plate supply table 8 to the discharge plate table 9, the transfer was performed on the transfer guide plate 4 provided in the middle at a transfer speed of 100 cm / min.
To the four spray pipes 5, the developer stored in the developer tank 10 is supplied by the circulation pump 11 through the filter 7 through the conduit 6, and is supplied by showering from each spray pipe 5 to the plate surface. . The capacity of the developer tank 10 was 10 liters, and the developer was circulated.
The lithographic printing plate discharged from the automatic development processor was dried by a drier (not shown) without washing with water.
The rotating direction of the rotating brush roll used in the present invention may be the same or opposite to the transport direction of the planographic printing plate precursor of the present invention. Thus, when using two or more rotating brush rolls, it is preferable that these rotate in the opposite direction. This further ensures the removal of the image forming layer in the non-image area. Furthermore, it is also effective for development to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

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

(Examples 1-8 and Comparative Examples 1-5)
<Production of support>
An aluminum plate (material 1050, tempered H16) having a thickness of 0.24 mm was immersed in a 5% aqueous sodium hydroxide solution maintained at 65 ° C., degreased for 1 minute, and then washed with water. This degreased aluminum plate was neutralized by dipping in a 10% aqueous hydrochloric acid solution maintained at 25 ° C. for 1 minute, and then washed with water. Next, this aluminum plate was subjected to electrolytic surface roughening with an alternating current for 60 seconds under conditions of 25 ° C. and a current density of 100 A / dm ^{2 in} a 0.3 wt% hydrochloric acid aqueous solution, and then kept at 60 ° C. Desmutting treatment was performed for 10 seconds in a 5% aqueous sodium hydroxide solution. The surface-roughened aluminum plate subjected to desmut treatment was anodized in a 15% aqueous sulfuric acid solution at 25 ° C., a current density of 10 A / dm ² , and a voltage of 15 V for 1 minute, and further 1% polyvinylphosphonic acid Hydrophilic treatment was performed at 75 ° C. using an aqueous solution to prepare a support. When the surface roughness was measured, it was 0.44 μm (Ra display according to JIS B0601).

<Formation of photosensitive layer>
A photosensitive layer coating solution (A) having the following composition was bar coated on the support and then oven-dried at 90 ° C. for 60 seconds to prepare lithographic printing plate precursors of Examples 1 to 8 and Comparative Examples 1 to 5. . The dry coating amount was 1.3 g / m ² .

<Photosensitive layer coating solution (A)>
-The following binder polymer (1) (weight average molecular weight: 80,000) 0.34 parts by weight-The following polymerizable compound (1) 0.68 parts by weight (PLEX6661-O, manufactured by Evonik Degussa Japan Co., Ltd.)
The following sensitizing dye (1) 0.06 part by weight The following polymerization initiator (1) 0.18 part by weight The following chain transfer agent (1) 0.02 part by weight A dispersion of ε-phthalocyanine pigment 0.40 Parts by weight (pigment: 15 parts by weight, dispersant (allyl methacrylate / methacrylic acid copolymer (copolymerization molar ratio 83/17)): 10 parts by weight, cyclohexanone: 15 parts by weight)
・ 0.01 parts by weight of thermal polymerization inhibitor (N-nitrosophenylhydroxylamine aluminum salt)
-The following fluorosurfactant (1) (weight average molecular weight: 11,000) 0.001 part by weight-Polyoxyethylene-polyoxypropylene condensate 0.02 part by weight (Asahi Denka Kogyo Co., Ltd., Pluronic L44)
-Dispersion of yellow pigment 0.04 parts by weight (yellow pigment Novoperm Yellow H2G (manufactured by Clariant): 15 parts by weight, dispersant (allyl methacrylate / methacrylic acid copolymer (copolymerization molar ratio 83/17)): 10 Parts by weight, cyclohexanone: 15 parts by weight)
1-methoxy-2-propanol 3.5 parts by weight Methyl ethyl ketone 8.0 parts by weight Polymerization inhibitor described in Table 1 below Amount shown in Table 1

  In Table 1, a-1 to a-4, c-1 and c-2 are the compounds shown below.

<Formation of protective layer 1>
On the photosensitive layer, a protective layer coating solution (A) having the following composition was applied using a bar so that the dry coating amount was 1.0 g / m ^2, and then dried at 125 ° C. for 70 seconds. A protective layer was formed to obtain a lithographic printing plate precursor.
<Protective layer coating solution (A)>
-0.6 part by weight of the following mica dispersion (A)-0.8 part by weight of sulfonic acid-modified polyvinyl alcohol (Goselan CKS-50, manufactured by Nippon Synthetic Chemical Co., Ltd., degree of saponification: 99 mol%, average degree of polymerization: 300, degree of modification: about 0.4 mol%)
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (molecular weight 70,000)
0.001 part by weight / surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.002 part by weight / water 13 part by weight

(Preparation of mica dispersion (A))
32 parts by weight of synthetic mica (Somasif ME-100, manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1,000 or more) was added to 368 parts by weight of water, and the average particle size (laser scattering method) was 0. 0 using a homogenizer. Dispersion was performed until the thickness became 5 μm, and a mica dispersion liquid (A) was obtained.

(1) Exposure, development and printing Each lithographic printing plate precursor having the above support, photosensitive layer and protective layer shown in Table 1 is a Violet semiconductor laser plate setter Vx9600 (InGaN-based semiconductor laser 405 nm, manufactured by FUJIFILM Electronic Imaging Ltd). Image exposure was carried out by mounting ± 10 nm emission / output 30 mW. As the exposure image, an image in which drawn thin lines having a width of 5 to 100 μm (5 μm intervals) were arranged as the drawn thin line evaluation image was used. For printing durability evaluation, an image capable of solid printing durability evaluation was used. For image drawing, imagewise exposure was performed with a resolution of 2400 dpi and a plate surface exposure of 0.05 mJ / cm ² .
Next, preheating is performed at 100 ° C. for 30 seconds, and then using the developer A having the following composition, the immersion time (development time) in the developer is set in the automatic development processing apparatus having the structure shown in FIG. Development processing was performed at a conveyance speed of 20 seconds.

<Developer A (pH = 9.7)> (Units are parts by weight)
・ Water 8329.8
・ Sodium carbonate 130
・ Sodium bicarbonate 70
・ Alkyl diphenyl ether disulfonate 500 (converted to solid content)
(Sanyo Chemical Industry Co., Ltd., Eleminor MON)
・ Gum arabic (weight average molecular weight: 200,000) 250
・ Hydroxyalkylated starch 700
(Nippon Chemical Co., Ltd .: Penon JE66)
・ Primary ammonium phosphate 20
2-Bromo-2-nitropropane-1,3-diol 0.1
2-Methyl-4-isothiazolin-3-one 0.1

  Next, 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 FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 ( Volume ratio)) and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) were used for printing at a printing speed of 6,000 sheets per hour.

[Evaluation]
Using the planographic printing plate precursors of Examples 1 to 8 and Comparative Examples 1 to 5, the printing durability and the drawn fine lines were evaluated as follows.

<Print durability>
As the number of printed sheets is increased, the image on the photosensitive layer formed on the planographic printing plate gradually wears out and the ink receptivity is lowered. Accordingly, the ink density of the image on the printing paper is lowered. Accordingly, the printing durability was evaluated based on the number of printed sheets when the ink density (reflection density) when using 10,000 g of the developer was reduced by 0.1 from the start of printing.

<Thin wire>
Each lithographic printing plate precursor was developed as described above, and the obtained printing plate was visually checked for the width of the drawn fine line in the main operation direction, and the drawn fine line was evaluated.

  As a result of the evaluation of the printing durability and the drawn fine line, as shown in Table 2, the lithographic printing plates of Examples 1 to 8 to which a phenothiazine-based polymerization inhibitor was added exhibited a small decrease in printing durability and no drawn fine line. Although it turned out that it was improving compared with the additive, it was unsatisfactory in the comparative example.

(Examples 9 to 16 and Comparative Examples 6 to 10)
<Surface treatment>
For the surface treatment, the following various treatments (a) to (k) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) Mechanical surface roughening treatment Using an apparatus as shown in FIG. 2, a suspension of a polishing agent (pumice) having a specific gravity of 1.12 and water is supplied as a polishing slurry to the surface of the aluminum plate. However, a mechanical surface roughening treatment was performed with a rotating roller-like nylon brush. In FIG. 2, 21 is an aluminum plate, 22 and 24 are roller brushes, 23 is a polishing slurry, and 25, 26, 27 and 28 are support rollers. The average particle size of the abrasive was 30 μm, and the maximum particle size was 100 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 45 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 2.6% by weight, an aluminum ion concentration of 6.5% by weight and a temperature of 70 ° C. / M ² dissolved. Then, water washing by spraying was performed.

(C) Desmutting treatment Desmutting treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by weight of ammonium ions) at a liquid temperature of 50 ° C. The AC power supply waveform is the waveform shown in FIG. 3, the time TP until the current value reaches the peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used, with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Then, water washing by spraying was performed.

(E) Alkali etching treatment The aluminum plate was subjected to an etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26% by weight and an aluminum ion concentration of 6.5% by weight to dissolve the aluminum plate by 0.50 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment was performed by spraying with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used in the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in the nitric acid aqueous solution.

(G) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 5.0 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The waveform of the AC power supply is electrochemically roughened using a trapezoidal trapezoidal wave AC with a time TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal trapezoidal wave AC Processed. Ferrite was used for the auxiliary anode.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. Then, water washing by spraying was performed.

(H) Alkali etching treatment The aluminum plate was subjected to etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26% by weight and an aluminum ion concentration of 6.5% by weight to dissolve the aluminum plate by 0.10 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(I) Desmutting treatment A desmutting treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), and then washing with water by spraying was performed.

(J) Anodizing treatment Anodizing treatment is carried out using an anodizing apparatus (first and second electrolysis section length 6 m, first and second feeding section length 3 m each, first and second feeding electrode section length 2.4 m each). went. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 50 g / L (containing 0.5% by weight of aluminum ions) and a temperature of 20 ° C. Then, water washing by spraying was performed.

(K) Alkali metal silicate treatment An aluminum support obtained by anodizing treatment was immersed in a treatment tank of a 1 wt% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C for 10 seconds. Acid salt treatment (silicate treatment) was performed. Thereafter, washing with water using well water was performed to obtain a support subjected to a surface silicate hydrophilization treatment.

Next, the following intermediate layer coating solution (B) was coated on the aluminum support subjected to the above surface treatment so as to have a dry coating amount of 10 mg / m ² and dried.
<Intermediate layer coating solution (B)>
・ Polyvinylphosphonic acid 0.017 weight part ・ Methanol 9.00 weight part ・ Water 1.00 weight part

<Formation of photosensitive layer>
The following coating solution (B) for the photosensitive layer is prepared and applied onto the intermediate layer formed as described above using a wire bar to produce lithographic printing plate precursors of Examples 9 to 16 and Comparative Examples 6 to 10. did. Drying was performed at 125 ° C. for 34 seconds using a warm air dryer. The coating amount after drying was 1.4 g / m ² .

<Coating solution for photosensitive layer (B)>
Infrared absorber (IR-1) 0.038 parts by weight Polymerization initiator A (S-1) 0.061 parts by weight Polymerization initiator B (I-1) 0.094 parts by weight Mercapto compound (E- 1) 0.015 part by weight / ethylenically unsaturated compound (M-1) 0.425 part by weight (trade name: A-BPE-4, Shin-Nakamura Chemical Co., Ltd.)
-Binder polymer A (B-1) (weight average molecular weight: 110,000) 0.311 parts by weight-Binder polymer B (B-2) (weight average molecular weight: 100,000) 0.250 parts by weight-Binder polymer C (B -3) (weight average molecular weight: 120,000) 0.062 parts by weight, additive (T-1) 0.079 parts by weight, polymerization inhibitor (Q-1) 0.0012 parts by weight, ethyl violet (EV-1) ) 0.021 parts by weight · Fluorosurfactant 0.0081 parts by weight (Megafac F-780-F Dainippon Ink & Chemicals, Inc., methyl isobutyl ketone (MIBK) 30% by weight solution)
-Methyl ethyl ketone 5.886 parts by weight-methanol 2.733 parts by weight-1-methoxy-2-propanol 5.886 parts by weight-polymerization inhibitor described in Table 4 Amount described in Table 4

  In addition, the infrared absorber (IR-1), the polymerization initiator A (S-1), the polymerization initiator B (I-1), and the mercapto compound (E-1) used in the photosensitive layer coating solution (B). ), Polymerizable compound (M-1), binder polymer A (B-1), binder polymer B (B-2), binder polymer C (B-3), additive (T-1), polymerization inhibitor ( The structures of Q-1) and ethyl violet (EV-1) are shown below. In the following, Me represents a methyl group.

  In Table 4, a-1 to a-4, c-1 and c-2 are the compounds shown above.

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

<Formation of upper protective layer>
On the lower protective layer, an organic filler (Art Pearl J-7P, manufactured by Negami Industrial Co., Ltd.), synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol ( L-3266: Saponification degree 87 mol%, polymerization degree 300, sulfonic acid-modified polyvinyl alcohol, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), thickener (Serogen FS-B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Then, a mixed aqueous solution of the surfactant (Emulex 710, manufactured by Nippon Emulsion Co., Ltd.) is applied with a wire bar and dried at 125 ° C. for 30 seconds with a hot air dryer. It was.
The content ratio of the organic filler / synthetic mica (solid content) / polyvinyl alcohol / thickener / surfactant in the mixed aqueous solution (upper protective layer forming coating solution) is 3.2 / 2.0 / 80. 5 / 11.5 / 2.8 (% by weight), and the coating amount (the coating amount after drying) is 1.76 g / m ^2.
Met.

<Formation of back coat layer>
A back coat layer similar to that in Example 1 of JP-A-6-35174 was provided on the side opposite to the side of the planographic printing plate precursors A and B on which the photosensitive layer and protective layer were provided.

[Exposure, development and printing]
<Plate making>
The obtained lithographic printing plate precursor was processed in the order of steps of exposure, development, and drying.
Light source (setter) used for exposure: Image-like exposure was performed with an infrared semiconductor laser (Trendsetter 3244VX manufactured by Creo, equipped with a water-cooled 40 W infrared semiconductor laser) under conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2,400 dpi. It was. As the exposure image, an image in which drawn thin lines having a width of 5 to 100 μm (5 μm intervals) were arranged as the drawn thin line evaluation image was used. For printing durability evaluation, an image capable of solid printing durability evaluation was used.
After the exposure, the heat treatment and the water washing treatment were not carried out, and the development treatment was carried out with an automatic development treatment apparatus having a structure shown in FIG. The pH of the developer was 9.7. The automatic development processing apparatus has two rotating brush rolls, and the first brush roll is a brush roll having an outer diameter of 50 mm in which fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 17 mm) are implanted. Used, 200 revolutions per minute in the same direction as the conveying direction (peripheral speed 0.52 m / sec at the tip of the brush), the second brush roll has a polybutylene terephthalate fiber (hair diameter 200 μm, hair length A brush roll having an outer diameter of 50 mm implanted with a thickness of 17 mm) was rotated 200 times per minute in the direction opposite to the conveying direction (peripheral speed of the brush tip of 0.52 m / sec). 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 printing plate. The tank capacity of the developer was 10 liters.

<Developer B>
-Water 8619.3 parts by weight-Sodium carbonate 130 parts by weight-Sodium hydrogen carbonate 70 parts by weight-New Coal B4SN (100% conversion) (manufactured by Nippon Emulsifier Co., Ltd.) 400 parts by weight-Gum arabic (weight average weight: 200,000) ) 400 parts by weight-Phosphate modified starch (manufactured by Nissho Chemical Co., Ltd .: Petrocoat HN25) 200 parts by weight-80 parts by weight of ethylenediaminetetraacetate tetrasodium salt-2-bromo-2-nitropropane-1,3-diol 0.1 part by weight 2-methyl-4-isothiazolin-3-one 0.1 part by weight

  The obtained lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and fountain solution (EU-3 (etch solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio). )) And TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), printing was performed at a printing speed of 6,000 sheets per hour.

[Evaluation]
Using the lithographic printing plate precursors of Examples 9 to 16 and Comparative Examples 6 to 10, the printing durability and the drawn fine lines were evaluated in the same manner as in Example 1.

  As a result of the evaluation of the printing durability and the drawn fine line, as shown in Table 5, in the planographic printing plates of Examples 9 to 16 to which the phenothiazine polymerization inhibitor was added, the decrease in printing durability was small and no drawn fine line was observed. Although it turned out that it was improving compared with the additive, it was unsatisfactory in the comparative example. Further, as shown in Table 6, it can be seen that the addition amount of the phenothiazine-based polymerization inhibitor is preferably 0.01% to 0.05% of the polymerizable compound from the balance between the fine line and the printing durability.

(Examples 17 to 24 and Comparative Examples 11 to 15)
(Production of support)
An aluminum plate (material JIS A1050) having a thickness of 0.3 mm is etched by immersing in a 10 wt% aqueous sodium hydroxide solution at 60 ° C for 25 seconds, washed with running water, neutralized and washed with a 20 wt% aqueous nitric acid solution, and then Washed with water. This was subjected to an electrolytic surface roughening treatment using a sinusoidal alternating waveform current in a 1 wt% aqueous nitric acid solution at an anode time electricity of 300 coulomb / dm ² . Subsequently, after dipping in a 1% by weight aqueous sodium hydroxide solution 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, the current density in a 20% by weight sulfuric acid aqueous solution was 2A / current density. Anodization was performed for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² under the condition of dm ² . 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).

Next, the following undercoat liquid (C) was bar-coated and then oven-dried at 80 ° C. for 10 seconds to prepare a support having an undercoat layer having a dry coating amount of 10 mg / m ² .

<Undercoat liquid (C)>
・ Undercoat compound (1) below (weight average molecular weight: 50,000) 0.017 parts by weight • 9.00 parts by weight of methanol • 1.00 part by weight of water

[Preparation of lithographic printing plate precursor]
A photosensitive layer coating solution (C) having the following composition was bar coated on the support provided with the undercoat layer, followed by oven drying at 100 ° C. for 44 seconds, and a photosensitive layer having a dry coating amount of 1.3 g / m ² . A protective layer coating solution (C) having the following composition was coated on the bar, followed by oven drying at 125 ° C. for 70 seconds to form a protective layer having a dry coating amount of 1.25 g / m ^2. The lithographic printing plate precursors 17-17 and Comparative Examples 11-15 were prepared.

<Photosensitive layer coating solution (C)>
-The following binder polymer P-22 (weight average molecular weight: 62,000, not, the numerical value at the bottom of each monomer in the following represents mol%) 0.45 parts by weight-The polymerizable compound (1) 0.52 weight (PLEX 6661-O, manufactured by Degussa Japan Co., Ltd.)
-0.04 part by weight of the sensitizing dye (1)-0.08 part by weight of the polymerization initiator (1)-0.05 part by weight of the co-sensitizer (1) (the chain transfer agent (1)) -Dispersion of phthalocyanine pigment 0.40 part by weight (pigment: 15 parts by weight, dispersant The binder polymer (1): 10 parts by weight, solvent: cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15 parts by weight / 20 parts by weight / 40 parts by weight)
-Thermal polymerization inhibitor 0.006 parts by weight (N-nitrosophenylhydroxylamine aluminum salt)
-Fluorosurfactant (1) 0.002 parts by weight-1-methoxy-2-propanol 8.0 parts by weight-Methyl ethyl ketone 8.0 parts by weight-Polymerization inhibitor described in Table 7 below Table 7 amount

  In Table 7, a-1 to a-4, c-1 and c-2 are the compounds shown above.

<Protective layer coating solution (C)>
-Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.02 parts by weight-Water 13 parts by weight-CKS50: manufactured by Nippon Synthetic Chemical Co., Ltd. (degree of saponification: 99 mol%, average degree of polymerization: 300) 0.66 parts by weight Mica dispersion: Synthetic mica (Somasif MEB-3L, manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1,000 or more) 1.6 weights Part / Filler: Art Pearl J-7P (Negami Kogyo Co., Ltd., silica-coated particles, molecular weight 100,000, 20% by weight) 0.16 parts by weight

[Exposure, development and printing]
Each of the above lithographic printing plate precursors was prepared by using FUJIFILM Electronic Imaging Ltd. Image exposure was performed using a Violet semiconductor laser plate setter Vx9600 (equipped with InGaN-based semiconductor laser 405 nm ± 10 nm emission / output 30 mW). The image was drawn with a resolution of 2438 dpi using an FM screen (TAFFETA 20) manufactured by Fuji Film Co., Ltd., and a 50% flat screen was drawn with a plate exposure of 0.09 mJ / cm ² .
Next, after preheating at 100 ° C. for 30 seconds, development processing was performed with an automatic development processor having a structure shown in FIG. The pH of the developer was all adjusted to 4.5 using phosphoric acid and sodium hydroxide. The automatic processor has two rotating brush rolls, and the first brush roll is a brush roll having an outer diameter of 50 mm in which fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 17 mm) are implanted. Used, 200 revolutions per minute in the same direction as the conveying direction (peripheral speed 0.52 m / sec at the tip of the brush), the second brush roll has a polybutylene terephthalate fiber (hair diameter 200 μm, hair length A brush roll having an outer diameter of 50 mm implanted with a thickness of 17 mm) was rotated 200 times per minute in the direction opposite to the conveying direction (peripheral speed of the brush tip of 0.52 m / sec). 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 printing plate. The tank capacity of the developer was 10 liters.

<Developer C>
-100 parts by weight of water-10 parts by weight of the following surfactant W-8-10 parts by weight of gum arabic (weight average molecular weight: 200,000)-0.1 parts by weight of monobasic ammonium phosphate-0.1 parts by weight of citric acid- Ethylenediaminetetraacetate tetrasodium salt 0.1 parts by weight 2-bromo-2-nitropropane-1,3-diol 0.001 part by weight 2-methyl-4-isothiazolin-3-one 0.001 part by weight

  The obtained lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and fountain solution (EU-3 (etch solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio). )) And TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), printing was performed at a printing speed of 6,000 sheets per hour.

[Evaluation]
Using the lithographic printing plate precursors of Examples 17 to 24 and Comparative Examples 11 to 15, the printing durability and the drawn fine lines were evaluated in the same manner as in Example 1.

  As a result of the evaluation of the printing durability and the drawn fine line, as shown in Table 8, the lithographic printing plates of Examples 17 to 24 to which a phenothiazine polymerization inhibitor was added showed a small decrease in printing durability and no drawn fine line. Although it turned out that it was improving compared with the additive, it was unsatisfactory in the comparative example.

It is explanatory drawing which shows the structure of an automatic image development processing apparatus. It is a side view which shows the concept of the process of the brush graining used for the machine roughening process in preparation of an aluminum support body. It is a graph which shows an example of the alternating waveform current waveform figure used for the electrochemical roughening process in preparation of an aluminum support body.

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 21: Aluminum plate 22, 24: Roller brush 23: Polishing slurry liquid 25, 26, 27, 28: Support roller

Claims (8)

On a support, (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, (D) a binder polymer, and have a photosensitive layer containing (E) phenothiazine compound,
The (B) polymerization initiator is an onium salt and / or a hexaarylbiimidazole compound,
The lithographic printing plate precursor wherein the (E) phenothiazine-based compound is a compound represented by the following formula (1) .

(In formula (1), X and Y each independently represent a halogen atom, an alkyl group, an alkoxy group or an alkylthio group, and p and q each independently represent an integer of 0 to 4.) The lithographic printing plate precursor according to claim 1, further comprising a layer containing a resin having a phosphoric acid group and / or a phosphonic acid group between the support and the photosensitive layer. The lithographic printing plate according to claim 1 or 2 , wherein the content of the (E) phenothiazine compound is 0.005 to 0.1 parts by weight with respect to 100 parts by weight of the total weight of the polymerizable compound (C). Original edition. The content of the (E) phenothiazine compound, wherein the total weight 100 parts by weight of the polymerizable compound (C), in any one of claims 1 to 3 is 0.01 to 0.05 parts by weight The lithographic printing plate precursor described. An exposure step for image exposure of the lithographic printing plate precursor according to any one of claims 1 to 4 , and
A plate making method of a lithographic printing plate comprising a developing step of removing a photosensitive layer in a non-exposed portion in the presence of a developer. The lithographic printing plate making method according to claim 5 , wherein the developer has a pH of 2 to 11. The lithographic printing plate making method according to claim 5 or 6 , wherein the developing step is a step of removing the photosensitive layer in the non-exposed area and gumming with one solution. The plate making method of a lithographic printing plate according to any one of claims 5 to 7 , wherein a water washing step is not performed before and after the development step.

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