JP2010078686A - Lithographic printing plate precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing plate precursor which enables image formation with an infrared laser, can form a strong film excellent in the chemical and scratch resistances of an image area, has good developability and development latitude in a non-image area, and improves printing durability when heat-treated at a high temperature after development. <P>SOLUTION: The lithographic printing plate precursor includes, on a support in the following order, a lower layer containing (A) a polymer compound having a (meth)acrylamide structural unit having a hydroxy group in a side chain, and (B) a recording layer containing (B) a polymer compound having a maleimide structural unit having a carboxy group in a side chain and (C) a compound which absorbs light and generates heat. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a positive type lithographic printing plate precursor whose solubility in an alkaline aqueous solution is improved by applying energy such as exposure, and in particular, it can be directly made by scanning with a laser beam based on a digital signal from a computer or the like. The present invention relates to a positive lithographic printing plate precursor capable of direct plate making.

  In recent years, the development of lasers has been remarkable. In particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared region to the infrared region have been increasing in output and size. Therefore, these lasers are very useful as an exposure light source when making a plate directly from digital data such as a computer.

The lithographic printing plate precursor for infrared laser, which uses an infrared laser having a light emitting region in the infrared region as an exposure light source, is usually an alkaline aqueous solution-soluble binder resin, an infrared absorbing dye that absorbs light, and generates heat. A recording layer containing When such a lithographic printing plate precursor for infrared laser is subjected to infrared laser exposure, if it has a positive recording layer, the IR dye or the like in the lithographic printing plate precursor for infrared laser in the unexposed portion (image portion) and the binder resin It acts as a dissolution inhibitor that substantially lowers the solubility of the binder resin by the interaction of the above, and in the exposed area (non-image area), the IR dye absorbs light and generates heat. And the interaction between the binder resin and the binder resin are reduced. Therefore, at the time of development, the exposed portion (non-image portion) is dissolved and removed in the alkaline developer to form a lithographic printing plate.
However, in such a positive lithographic printing plate material for infrared laser, compared to a positive lithographic printing plate material made by UV exposure, a resin having high solubility in a solvent such as an alkali developer must be used as a binder resin. Therefore, there is a problem that the photosensitive composition constituting the recording layer is eluted when the plate surface is wiped with the cleaner. there were.

As described above, it is important to improve resistance to various printing chemicals. For example, if the chemical resistance of the surface of the recording layer is low, the image area may be altered or dissolved due to chemical splashing during printing, or wiping residue after use of the chemical, so that there is no ink in the image area during printing, This is not preferable because white spots are generated on the printed matter. In addition, when the image surface has low scratch resistance, the original image portion is worn away by rubbing and being scratched by a member in contact with the surface when performing exposure and development automatically. There is a problem that arises.
When a large number of high-quality prints are printed on the formed printing plate, it is essential to improve these chemical resistance and scratch resistance. Various studies have been made on these issues. For example, a technique for forming a recording layer having an alkali-soluble resin excellent in chemical resistance has been proposed (see, for example, Patent Document 1). However, although this recording layer is improved in chemical resistance, there is a problem that the periphery of a slight scratch that has entered before development is easily dissolved during development, and white spots are generated in the image area.
In addition, it is considered that making the structure of the resin layer of the lithographic printing plate two or more layers is useful for achieving both chemical resistance and scratch resistance, and a maleimide compound is used as a structural unit in the lower layer of the multi-layer recording layer. It has been proposed to use a high molecular compound (for example, see Patent Document 2). Although this recording layer is improved in chemical resistance, the adhesion between the lower layer and the upper recording layer provided adjacent thereto is not always sufficient, and further improvement has been demanded in this respect.
JP 2005-62875 A US Published Patent No. 2004/0067432

An object of the present invention, which has been made to overcome the above-mentioned drawbacks of the prior art, is that an image can be formed by an infrared laser, and a strong film excellent in chemical resistance and scratch resistance of the image area can be formed. An object of the present invention is to provide a lithographic printing plate precursor having good developability in part.
A further object of the present invention is to provide a lithographic printing plate precursor whose printing durability is remarkably improved when it is heat-treated at a high temperature after development.

As a result of diligent research, the present inventor has found that the above object can be achieved by using one of two kinds of polymers containing a specific copolymerization component as a lower layer and the other as an upper recording layer. completed.
That is, the lithographic printing plate precursor according to the invention has (A) a polymer compound having a structural unit represented by the following general formula (I) on a support (hereinafter, referred to as (A) a specific polymer as appropriate). (B) a polymer compound having a structural unit represented by the following general formula (II) (hereinafter, appropriately referred to as (B) specific polymer), and (C) absorbing light. And a recording layer containing a compound that generates heat.

[In the general formula (I), R ¹ represents a hydrogen atom or a methyl group. R ² represents an alkylene group having 1 to 4 carbon atoms. ]

[In General Formula (II), X ¹ represents an alkylene group, an arylene group, an arylene group, and a divalent linking group including at least one of them. n represents an integer of 1 to 3. ]
Here, (A) Content of the high molecular compound which has a structural unit represented by general formula (I) is 20 mass%-95 mass% in the total solid which comprises a lower layer, Said (B) In a preferred embodiment, the content of the polymer compound having the structural unit represented by the general formula (II) is 3% by mass to 40% by mass in the total solid content constituting the upper recording layer.

  Here, “sequentially comprising each of the layers” means having a layer structure in which at least the lower layer and the upper recording layer are provided in this order on a support, but other layers provided as desired. For example, the existence of an undercoat layer, a protective layer, a backcoat layer, etc. is not denied.

Although the operation of the present invention is not clear, it is presumed as follows.
The (A) specific polymer used in the lithographic printing plate precursor according to the present invention includes a structural unit represented by the general formula (I), so that it has excellent solvent resistance. In order to form a film excellent in solvent resistance and excellent in alkali resistance, it is possible to form a layer containing each of these layers, thereby providing excellent chemical resistance in the lower layer, and even in the upper recording layer. The chemical resistance is improved, and the scratch resistance of the surface can be controlled by the interaction between the specific polymer (B) and the photothermal conversion agent independently of the lower layer. The (A) specific polymer contained in the lower layer has a partial structure that undergoes a crosslinking reaction by heat, and this partial structure is crosslinked with the functional group contained in the (B) specific polymer or alkali-soluble binder polymer contained in the upper layer. Therefore, when heat treatment is performed at a high temperature after development, a cross-linked structure is formed between the upper recording layer and the lower layer by heating for a predetermined time, and this can significantly improve printing durability. Conceivable.
For this reason, the lithographic printing plate precursor having such a positive recording layer maintains an unexposed portion with a strong film excellent in alkali developer resistance and chemical resistance, and, for example, in an infrared laser exposure portion. Is a short exposure due to high energy, so that the above-mentioned cross-linking reaction is not caused and the interaction is released, and the release of the interaction reveals the alkali solubility of the specific polymer (A) in the lower layer, thereby recording the exposed area. It is considered that the layer is removed quickly and has excellent image forming properties.

According to the present invention, a lithographic printing plate precursor capable of forming an image with an infrared laser, capable of forming a strong film excellent in chemical resistance and scratch resistance in an image area, and having good developability in a non-image area. Can be provided.
The lithographic printing plate precursor according to the invention also has an advantage that the printing durability is remarkably improved when heat treatment is performed at a high temperature after development.

The lithographic printing plate precursor according to the invention comprises, on a support, (A) a lower layer containing a polymer compound having a structural unit represented by the following general formula (I), and (B) the following general formula (II): And a recording layer containing a polymer compound having a structural unit represented, and (C) a compound that absorbs light and generates heat.
Hereinafter, each component contained in the lower layer and the upper recording layer (hereinafter sometimes simply referred to as “recording layer”) of the lithographic printing plate precursor according to the invention will be sequentially described.

<(A) Lower layer containing a polymer compound having a structural unit represented by the following general formula (I)>
In the present invention, a hydrophilic support surface is provided with a lower layer, and the lower layer contains the following (A) specific polymer and an additive used as desired.
[(A) Specific polymer]
The (A) specific polymer used in the lower layer in the present invention is a polymer having a structural unit represented by the following general formula (I).

In the general formula (I), R ¹ represents a hydrogen atom or a methyl group. R ² represents an alkylene group having 1 to 4 carbon atoms.
Here, R ¹ and R ³ are each preferably an embodiment in which each is a hydrogen atom. R ² is preferably an alkylene group having 1 to ² carbon atoms, more preferably a methylene group.
(A) The specific polymer may contain only one type of structural unit represented by the general formula (I), or may contain two or more types.
(A) As for content of the structural unit represented by general formula (I) in a specific polymer, 1-50 mol% is preferable, 5-45 mol% is more preferable, and 10-40 mol% is still more preferable.

(A) It is preferable that a specific polymer is a copolymer containing the structural unit which has an acid group in addition to the said structural unit.
Here, examples of the structural unit having an acid group that is preferably used as a copolymerization component include structural units derived from monomers having an acidic group listed in the following (1) to (6).
(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) sulfonic acid group _(-SO 3 H)
(6) phosphoric acid group (-OPO ₃ H ₂₎
In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrogen atom or a hydrocarbon group which may have a substituent. .
As a monomer which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.

(1) Examples of the structural unit having a phenol group include structural units contained in novolak resins, xylenol resins, resol resins and the like.
Moreover, the compound which has a phenol group in a side chain can also be mentioned, such as acrylamide, methacrylamide, acrylic ester or methacrylic ester having a phenol group, or hydroxystyrene.

  (2) Examples of the structural unit having a sulfonamide group include structural units derived from a monomer having a sulfonamide group. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. Among these, low molecular weight compounds having an acryloyl group, an allyl group, or a vinyloxy group, and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule are preferable. For example, the following formulas (i) to (v ) -Derived structural units.

(In the formula, X ¹ and X ² each independently represent —O— or —NR ^7. R ¹ and R ⁴ each independently represents a hydrogen atom or —CH _3. R ² , R ⁵ , R ⁹ , R ¹² and R ¹⁶ each independently represents an alkylene group, a cycloalkylene group, an arylene group or an aralkylene group having 1 to 12 carbon atoms, and R ³ , R ⁷ and R ¹³ each independently represent Represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group, and R ⁶ and R ¹⁷ are each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group or an aryl group. R ⁸ , R ¹⁰ and R ¹⁴ each independently represents a hydrogen atom or —CH ₃ , R ¹¹ and R ¹⁵ each independently represents a single bond or an alkylene having 1 to 12 carbon atoms. Group, cycloalkylene group, arylene group or aralkylene group Y ¹ and Y ² each independently represents a single bond or CO. The above alkylene group, cycloalkylene group, arylene group, aralkylene group, alkyl group, cycloalkyl The group, aryl group, or aralkyl group may have a substituent, and a preferred substituent is an alkyl group.)

  Among the compounds represented by the formulas (i) to (v), in the lithographic printing plate precursor having the recording layer having the multilayer structure of the present invention, in particular, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) ) Methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

  (3) As a structural unit having an active imide group. For example, the structural unit derived from the compound which has an active imide group can be mentioned. Examples of the compound as described above include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule.

  Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

(4) Examples of the structural unit having a carboxylic acid group include a structural unit derived from a compound having one or more carboxylic acid groups and polymerizable unsaturated groups in the molecule. In the present invention, acrylic acid, methacrylic acid, maleic acid and itaconic acid can be preferably used.
(5) Examples of the structural unit having a sulfonic acid group include a structural unit derived from a compound having one or more sulfonic acid groups and polymerizable unsaturated groups in the molecule.

(6) As the structural unit having a phosphate group, for example, a weight having a minimum structural unit derived from a compound having at least one phosphate group and at least one polymerizable unsaturated group in the molecule as a main structural unit is used. Coalescence can be mentioned.

Among the structural units having an acidic group selected from the above (1) to (6), those containing (4) a structural unit having a carboxylic acid group are most preferable.
The amount of acidic groups contained in the specific polymer (A) of the present invention is preferably an amount in which the acid value of the polymer is in the range of 10 to 35 meq / g.

Further, (A) the specific polymer may further contain a copolymer component other than the structural unit.
Such a structural unit is not particularly specified as long as it is a structural unit derived from a monomer that can be copolymerized with other components of the specific polymer (A) used in the present application, but (meth) acrylic acid ester, (meth) acrylonitrile , Styrenic compounds, maleimides, and derived structural units.
More specifically, for example, methyl methacrylate, methyl acrylate, ethyl methacrylate, N-methoxymethyl methacrylate, methoxymethyl methacrylate, N-phenylmaleimide, N-cyclohexylmaleimide, benzylmaleimide, styrene, p-methyl Examples include structural units derived from monomers such as styrene, methacrylamide, acrylamide, acrylonitrile, maleic anhydride, and allyl acrylate.

(A) Although a preferable aspect is mentioned as a specific polymer below, it is not limited to this.
(1) N-methoxymethylmethacrylamide / methacrylic acid / acrylonitrile = 40/30/30 (molar ratio), copolymer having a weight average molecular weight of 60,000
(2) N-methoxymethylmethacrylamide / methacrylic acid / benzyl methacrylate = 50/25/25 (molar ratio), copolymer having a weight average molecular weight of 70,000
(3) N-methoxyethylmethacrylamide / methacrylic acid / N-phenylmaleimide = 65/20/15 (molar ratio), copolymer having a weight average molecular weight of 40,000
(4) N-methoxyethylmethacrylamide / 4-hydroxyphenylmethacrylamide / acrylonitrile = 30/25/45 (molar ratio), copolymer having a weight average molecular weight of 50,000
(5) Copolymer of methoxymethyl methacrylate / methacrylic acid / p-hydroxystyrene / acrylonitrile = 40/20/5/35 (molar ratio), weight average molecular weight 70,000
(6) Copolymer having methoxymethyl methacrylate / methacrylic acid / N-phenylmaleimide / acrylonitrile = 25/25/10/40 (molar ratio) and weight average molecular weight 70,000

The weight average molecular weight of the specific polymer (A) in the present invention is preferably 300 to 150,000, more preferably 10,000 to 60000.
The weight average molecular weight can be measured by a method using gel permeation chromatography using polystyrene as a standard sample.
Such (A) specific polymer can be synthesized by the method described in US Pat. No. 7,144,661.

In the present invention, (A) one type or two or more types of specific polymers can be appropriately mixed and used.
The content of the specific polymer (A) in the lower layer of the lithographic printing plate precursor according to the present invention is 20 lipids relative to the total solid content of the composition constituting the lower layer from the viewpoint of the effects of burning printing durability and scratch resistance. The amount is preferably in the range of 95% by mass to 95% by mass, and more preferably in the range of 60% by mass to 90% by mass.
Other components that can be included in the lower layer are described below.

<(B) Recording layer containing a polymer compound having a structural unit represented by the following general formula (II) and (C) a compound that absorbs light and generates heat>
The lithographic printing plate precursor according to the invention includes the lower layer on a support, and further has (B) a polymer compound having a structural unit represented by the general formula (II), and (C) absorbing light. And a recording layer containing a compound that generates heat (referred to as an upper recording layer in this specification as appropriate).

[(B) Specific polymer]
(B) The specific polymer is a polymer having a structural unit represented by the following general formula (II).

In the general formula (II), X ¹ represents an alkylene group, an arylene group, an arylene group, and a divalent linking group including at least one of them. n represents an integer of 1 to 3.
n is preferably 1 or 2, and more preferably 1.
Here, examples of X ¹ include an alkylene group, an arylene group, an alkylene arylene group, an alkylene arylene group, an alkyleneoxyarylene group, an aryleneoxyarylene group, and an alkyleneoxyarylene group, and these linking groups are Further, it may be unsubstituted, and may further have a substituent unless the effects of the present invention are impaired.
Preferred are an alkylene group, an arylene group, an arylene group, an alkylenearylene group, and an arylenearylene group, more preferably a substituted or unsubstituted phenylene group. In particular, when n is 1, X ¹ is phenylene. It is preferably a group.

  The specific polymer (B) in the present invention preferably contains 3 to 15 mol%, more preferably 5 to 15 mol% of the structural unit represented by the general formula (II) from the viewpoint of scratch resistance and developability. More preferably.

The specific polymer (B) may further contain a copolymer component other than the structural unit.
Such a structural unit is not particularly specified as long as it is a structural unit derived from a monomer that can be copolymerized with other components of the specific polymer (B) used in the present application. Specifically, for example, methyl methacrylate, Methyl acrylate, ethyl methacrylate, ethyl acrylate, N-methoxymethyl methacrylate, methoxymethyl methacrylate, N-phenylmaleimide, N-cyclohexylmaleimide, benzylmaleimide, styrene, p-methylstyrene, methacrylamide, acrylamide, acrylonitrile , Structural units derived from monomers such as maleic anhydride and allyl acrylate.
These other structural units are preferably contained in the specific polymer (B) in an amount of 85 to 97 mol%, more preferably 85 to 95 mol%.

Examples of the (B) specific polymer that can be used in the present invention include a copolymer of N- (4-carboxyphenyl) maleimide and methyl methacrylate, and a copolymer of N- (4-carboxyphenyl) maleimide and ethyl acrylate. However, the present invention is not limited to this.
Such (B) specific polymer can be synthesized by the method described in US Pat. No. 7,169,518.

In the present invention, the weight average molecular weight (Mw) of the (B) specific polymer is preferably in the range of 1,000 to 150,000, more preferably in the range of 10,000 to 100,000, and most preferably It is in the range of 30,000-80,000.
The weight average molecular weight can be measured by a method using gel permeation chromatography (GPC) using polystyrene as a standard sample.

  In the present invention, one type or two or more types of (B) specific polymer can be appropriately mixed and used.

  In the present invention, the content of the specific polymer (B) is in the range of 3% by mass to 40% by mass with respect to the total solid content of the composition constituting the upper recording from the viewpoint of scratch resistance and chemical resistance. Is preferable, and the range of 5% by mass to 20% by mass is more preferable.

[(C) Compound that absorbs light and generates heat]
The upper recording layer according to the present invention needs to contain (C) a compound that absorbs light and generates heat (hereinafter, appropriately referred to as a photothermal conversion agent) in addition to the specific polymer (B). .
As the photothermal conversion agent that can be used in the present invention, any compound that generates heat upon exposure to a light source used for image formation can be used. However, the lithographic printing plate precursor of the present invention is image-formed by infrared laser exposure. It is preferable to use an infrared absorber that has a light absorption region in the infrared region of 700 nm or more, preferably 750 to 1200 nm, and expresses light / heat conversion ability by light in this wavelength range, specifically, Various dyes or pigments that absorb light in the above wavelength range and generate heat can be used.

  As the dye, commercially available dyes, for example, known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, 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, oxonol dyes And dyes such as diimonium dyes, aminium dyes, and croconium dyes.

  Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59- 48187, JP-A 59-73996, JP-A 60-52940, JP-A 60-63744, etc., naphthoquinone dyes, JP-A 58-112792, etc. And cyanine dyes described in British Patent 434,875.

  Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. .

  Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Furthermore, the dyes represented by the following general formulas (a) to (e) are preferable because they are excellent in photothermal conversion efficiency. Particularly, the cyanine dye represented by the following general formula (a) is preferably a positive electrode of the lithographic printing plate precursor according to the invention. When used in the mold recording layer, it is most preferable because it gives a high interaction with the alkali-soluble resin and is excellent in stability and economy.

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , —X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom 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 a carbon atom having 1 to 12 carbon atoms including a hetero atom. Indicates a hydrogen group. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.

In the above formula, Xa ^- has Za described later ^- is defined as for, 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 represent a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the recording 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 formula (a) has an anionic substituent in the structure and charge neutralization is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a hexagonal salt, in view of the storage stability of the recording layer coating solution. Fluorophosphate ions and aryl sulfonate ions.

  Specific examples of the cyanine dye represented by formula (a) that can be suitably used in the present invention include those exemplified below, and paragraph numbers [0017] to [0019] of JP-A-2001-133969. And those described in paragraph numbers [0012] to [0038] of JP-A No. 2002-40638 and paragraph numbers [0012] to [0023] of JP-A No. 2002-23360.

In the general formula (b), L represents a methine chain having 7 or more conjugated carbon atoms, the methine chain may have a substituent, and the substituents are bonded to each other to form a ring structure. Also good. Zb ⁺ represents a counter cation. Preferred counter cations include ammonium, iodonium, sulfonium, phosphonium, pyridinium, alkali metal cations (Na ⁺ , K ⁺ , Li ⁺ ) and the like. R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ are each independently a hydrogen atom or halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, carbonyl group, thio group, sulfonyl group, sulfinyl group, oxy group Or a substituent selected from amino groups, or a combination of two or three of these, and may be bonded to each other to form a ring structure. Here, in the general formula (b), those in which L represents a methine chain having 7 conjugated carbon atoms and those in which R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ all represent hydrogen atoms are readily available. From the viewpoint of the effect.

  Specific examples of the dye represented by formula (b) that can be suitably used in the present invention include those exemplified below.

In the general formula (c), Y ³ and Y ⁴ each represent an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. M represents a methine chain having 5 or more conjugated carbon atoms. R ^{21 to} R ²⁴ and R ^{25 to} R ²⁸ may be the same or different, and are each a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, thio Represents a group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. Further, wherein Za ^- include a counter anion, Za in the general formula (a) ^- it is synonymous.

  In the present invention, specific examples of the dye represented by formula (c) that can be suitably used include those exemplified below.

In the general formula (d), R ^{29 to} R ³² each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ³³ and R ³⁴ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represents an integer of 0 to 4. R ²⁹ and R ³⁰ , or R ³¹ and R ³² may be bonded to each other to form a ring, R ²⁹ and / or R ³⁰ is R ³³ , and R ³¹ and / or R ³² is R ^34. To form a ring, and when there are a plurality of R ³³ or R ³⁴ , R ³³ or R ³⁴ may be bonded to each other to form a ring. X ² and X ³ are each independently a hydrogen atom, an alkyl group, or an aryl group, and at least one of X ² and X ³ represents a hydrogen atom or an alkyl group. Q is a trimethine group or a pentamethine group which may have a substituent, and may form a ring structure together with a divalent organic group. Zc ^- represents a counter anion, Za in the general formula (a) ^- synonymous.

  In the present invention, specific examples of the dye represented by the general formula (d) that can be suitably used include those exemplified below.

In the general formula (e), R ^{35 to} R ⁵⁰ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a hydroxyl group, or a carbonyl group that may have a substituent. Group, thio group, sulfonyl group, sulfinyl group, oxy group, amino group, and onium salt structure. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein are IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements can be mentioned, among which copper, magnesium, iron, zinc, cobalt, aluminum, titanium, and vanadium are preferable.

  In the present invention, specific examples of the dye represented by formula (e) that can be suitably used include those exemplified below.

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

  Examples of the pigment include black pigment, yellow pigment, orange pigment, brown pigment, red pigment, purple pigment, blue pigment, green pigment, fluorescent pigment, metal powder pigment, and polymer-bonded dye. 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 A quinophthalone pigment, a dyed lake pigment, an azine pigment, a nitroso pigment, a nitro pigment, a natural pigment, a fluorescent pigment, an inorganic pigment, or carbon black can be used.

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

  The particle diameter of the pigment is preferably in the range of 0.01 μm to 10 μm, preferably in the range of 0.05 μm to 1 μm, from the viewpoint of the stability of the dispersion in the coating liquid and the uniformity of the recording layer. More preferably, it is particularly preferably in the range of 0.1 μm to 1 μm.

  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 pigments or dyes (light-to-heat conversion agents) are 0.01 to 50% by mass with respect to the total solid content constituting the upper recording layer, preferably from the viewpoint of the balance between sensitivity, film uniformity and durability, preferably 0.1 to 10% by mass, particularly preferably in the case of a dye, 0.5 to 10% by mass, and particularly in the case of a pigment, 0.1 to 10% by mass can be added.
The photothermal conversion agent may be further contained in the lower layer for the purpose of improving sensitivity. In this case, the content of the photothermal conversion agent is preferably 0.01 to 50% by mass, and more preferably 0.1 to 10% by mass with respect to the total solid content of the lower layer.

[Other ingredients]
In the lower layer and the upper recording layer provided in the lithographic printing plate precursor according to the invention, (A) a specific polymer as an essential component in the lower layer, (B) a specific polymer as an essential component in the upper recording layer, and (C) In addition to the photothermal conversion agent, various compounds can be used in combination as required as long as the effects of the present invention are not impaired.

  For example, the two layers can contain other aqueous solution-soluble resins other than (A) specific polymer and (B) specific polymer, if necessary, in the recording layer. In this case, the other alkali-soluble resin is not particularly limited, but a general-purpose novolac resin is preferable.

  Examples of the novolak resin include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, o-, m- / p -Any of mixing, m- / o-mixing and o- / p-mixing.) Mixed formaldehyde resins are mentioned. These may be used alone or in combination of two or more.

  These novolak resins preferably have a weight average molecular weight of 1,500 or more and a number average molecular weight of 300 or more. More preferably, the weight average molecular weight is 3,000 to 300,000, the number average molecular weight is 500 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .

Moreover, as a preferable alkali-soluble resin that can be used in combination, the acidic group listed in the following (1) to (6), which is a structural unit having an acidic group described in detail with respect to the acidic group, is the main chain and / or side of the polymer. Examples thereof include a polymer compound contained in the chain.
(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) sulfonic acid group _(-SO 3 H)
(6) phosphoric acid group (-OPO ₃ H ₂₎
In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrogen atom or a hydrocarbon group which may have a substituent. .

  Among the alkali-soluble resins having an acidic group selected from the above (1) to (6), (1) an alkali-soluble resin having a phenol group, (2) a sulfonamide group, and (3) an active imide group is preferable. An alkali-soluble resin having (1) a phenol group or (2) a sulfonamide group is most preferred from the viewpoint of sufficiently ensuring solubility in an alkaline developer, development latitude, and film strength.

As alkali-soluble resin which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.
(1) Examples of the alkali-soluble resin having a phenol group include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, m− / p. -The novolak resin mentioned above, such as a condensation polymer of mixed cresol and formaldehyde, a condensation polymer of phenol and cresol (any of m-, p-, or m- / p-mixed) and formaldehyde. What is included is mentioned, The condensation polymer of pyrogallol and acetone can be mentioned. Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned. Alternatively, a copolymer obtained by copolymerizing a compound having a phenol group in the side chain can also be used.

  Examples of the compound having a phenol group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.

  (2) Examples of the alkali-soluble resin having a sulfonamide group include a polymer composed of a minimum structural unit derived from a compound having a sulfonamide group as a main constituent component. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. Among them, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group, and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule is preferable. For example, the general formula (i) to the general formula ( and a compound represented by v).

  Among the compounds represented by the general formula (i) to the general formula (v), in the lithographic printing plate precursor according to the invention, in particular, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

  (3) Examples of the alkali-soluble resin having an active imide group include a polymer composed of a minimum structural unit derived from a compound having an active imide group as a main constituent component. Examples of the compound as described above include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule.

  Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

(4) As an alkali-soluble resin having a carboxylic acid group, for example, a minimum structural unit derived from a compound having at least one carboxylic acid group and polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.
(5) Examples of the alkali-soluble polymer having a sulfonic acid group include a minimum structural unit derived from a compound having at least one sulfonic acid group and a polymerizable unsaturated group in the molecule as a main structural unit. Can be mentioned.
(6) As an alkali-soluble resin having a phosphate group, for example, a minimum structural unit derived from a compound having at least one phosphate group and a polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.

  The minimum structural unit having an acidic group selected from the above (1) to (6) is not particularly limited to one kind, and two or more minimum structural units having the same acidic group or different acidic groups are included. What copolymerized 2 or more types of the minimum structural unit can also be used.

  The copolymer preferably contains 3 (10) mol% or more of a compound having an acidic group selected from (1) to (6) to be copolymerized in the copolymer. % Is more preferable. If it is the range of the said content, the solubility to the alkaline developing solution which does not contain a solvent substantially can be ensured, and a development latitude can fully be improved.

As the monomer component to be copolymerized with the polymerizable monomer having an acidic group, for example, monomers listed in the following (m1) to (m11) can be used, but are not limited thereto.
(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.

(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.
(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.

(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-phenylmaleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.

  In the present invention, other polymer compounds may be used in combination with two or more different polymer compounds.

  Among the other polymer compounds exemplified above, the other polymer compound that can be used in the lower layer is preferably a copolymer having a sulfonamide group and / or a carboxylic acid group, Can include alkyl (meth) acrylate, (meth) acrylamide, (meth) acrylonitrile, and N-phenylmaleimide.

  As other polymer compounds that can be used in the upper layer, novolac resins and xylenol resins are preferably used, such as phenol formaldehyde resins, m-cresol formaldehyde resins, p-cresol formaldehyde resins, m- / p-mixed cresols. Formaldehyde resin, phenol / cresol (m-, p-, o-, m- / p-mixed, m- / o-mixed and o- / p-mixed) mixed formaldehyde resin, 2,3-xylenol 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol resin, xylenol / phenol mixed resin, xylenol / novolak mixed resin, xylenol / novolak / phenol mixed Examples thereof include resins.

In the present invention, when the polymer compound having a phenolic hydroxyl group used in the lower layer is a cocondensation type resin using an aldehyde such as a phenol formaldehyde resin or a cresol aldehyde resin, the weight average molecular weight is 500 to 20,000. The number average molecular weight is preferably 200 to 10,000.
When the polymer compound having a phenolic hydroxyl group used in the lower layer is a polymer compound other than a cocondensation resin using an aldehyde such as phenol formaldehyde resin or cresol aldehyde resin, the weight average molecular weight is 2,000 or more, several Those having an average molecular weight of 500 or more are preferable, and more preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the degree of dispersion (weight average molecular weight / number average molecular weight). Is 1.1-10.

  As the addition amount of the other polymer compound in the present invention, both the upper layer and the lower layer are used in an addition amount of 30 to 99% by mass, preferably 50 to 99% by mass, particularly preferably 65 to 99% by mass. It is preferable that the addition amount of the polymer compound is within the above range because the upper layer and the lower layer thermosensitive layer have high durability and high sensitivity.

[Dissolution inhibitor]
Further, in order to adjust the solubility of the recording layer, when other onium salts, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, polyfunctional amine compounds, etc. are added, development of an alkali water-soluble polymer (alkali-soluble resin) is performed. It is preferable to add a so-called dissolution inhibitor that improves the dissolution inhibition function in the liquid, and among them, onium salts, o-quinonediazide compounds, sulfonic acid alkyl esters and the like are thermally decomposable, and in a state where they are not decomposed, alkali-soluble resins It is preferable to use a substance that substantially lowers the solubility in terms of improving the solubility of the image area in the developer.

Preferred examples of the onium salt used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salts, J.M. V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt, C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).
Among these onium salts, diazonium salts and quaternary ammonium salts are particularly preferable from the viewpoints of dissolution inhibition ability and thermal decomposability. In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable. Moreover, as a quaternary ammonium salt, the quaternary ammonium salt described as (1)-(10) in [Chemical 5] and [Chemical 6] in Unexamined-Japanese-Patent No. 2002-229186 is preferable.

  The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide helps the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder due to thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. The compounds described in pages 339 to 352 of “Light-sensitive systems” by John Coley (John Wiley & Sons. Inc.) can be used, and in particular, o-quinonediazide reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. The sulfonic acid esters or sulfonic acid amides are preferred. Further, benzoquinone (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17474, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

  The addition amount of the onium salt and / or the o-quinonediazide compound that is a degradable dissolution inhibitor is preferably 1 to 10% by mass with respect to the total solid content of each layer provided in the lithographic printing plate precursor, Preferably it is 1-5 mass%, Most preferably, it is the range of 1-2 mass%. These compounds can be used alone, but may be used as a mixture of several kinds.

  The amount of additives other than the o-quinonediazide compound is preferably 0.1 to 5% by mass, more preferably 0.1 to 2% by mass, and particularly preferably 0.1 to 1.5% by mass. The additive and binder according to the present invention are preferably contained in the same layer.

  Further, a dissolution inhibitor having no decomposability may be used in combination, and preferred dissolution inhibitors include sulfonate esters, phosphate esters, and aromatic carboxylic acids described in detail in JP-A-10-268512. Esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as well as lactone skeletons described in detail in JP-A-11-190903, N, N- Examples thereof include an acid color-forming dye having a diarylamide skeleton and a diarylmethylimino skeleton, which also serves as a colorant, and nonionic surfactants described in detail in JP-A No. 2000-105454.

Moreover, as a preferable additive used for a lower layer and an upper recording layer, cyclic acid anhydrides, phenols, organic acids, etc. can be mentioned from a viewpoint of improving a sensitivity. Further, a surfactant, an image colorant, and a plasticizer, which will be described later, can also be used as additives for the lower layer or the upper recording layer.
Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride described in US Pat. No. 4,115,128, Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 “-Trihydroxytriphenylmethane, 4,4 ′, 3”, 4 ”-tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. Examples thereof include sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755.
The proportion of the cyclic acid anhydride, phenols, and organic acids in each layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 0.1% by mass. 10% by mass.

  In addition to these, epoxy compounds, vinyl ethers, and further, phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group described in JP-A-8-276558, and the inventors previously proposed. A crosslinkable compound having an alkali dissolution inhibiting action described in JP-A-11-160860 can be appropriately added depending on the purpose.

Further, a printing-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images.

  As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of each layer.

  Furthermore, a plasticizer is added to the lower recording layer and the upper recording layer of the recording layer of the planographic printing plate precursor according to the present invention, if necessary, in order to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

[Manufacture of lithographic printing plate precursors]
(Coating solvent and coating method)
The lithographic printing plate precursor of the present invention is prepared on a support having a hydrophilic surface by preparing a coating solution in which components such as each specific polymer and photothermal conversion agent contained in the lower layer and the upper recording layer are dissolved in a solvent. The lower layer and the upper recording layer can be formed on the support by applying the lower layer coating solution and the upper recording layer coating solution in this order.
Further, depending on the purpose, a protective layer, a resin intermediate layer, a backcoat layer and the like which will be described later can be formed in the same manner.
As the coating solvent used here, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, Examples include dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited to. These solvents are used alone or in combination.
The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.

The coating, solid coating amount on the support obtained after drying, the top layer 0.05 to 2.0 g / ^{m 2,} the lower layer is preferably each 0.3 to 5.0 g / ^{m 2,} more preferably The upper layer is in the range of 0.1 to 1.0 g / m ² , and the lower layer is in the range of 0.5 to 3.0 g / m ² . Moreover, 0.05-1 are preferable, and, as for ratio (upper layer / lower layer) of the coating amount of an upper layer and a lower layer, More preferably, it is the range of 0.1-0.8.

  Various methods can be used as a method for applying the upper and lower layer coating solutions. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll Application etc. can be mentioned. As the coating amount decreases, the apparent sensitivity increases, but the film properties of each layer decrease.

<Support>
The support used in the lithographic printing plate precursor according to the present invention is a dimensionally stable plate-like material, and is not particularly limited as long as it satisfies the required properties such as strength and flexibility. 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 laminated with or vapor-deposited metal as described above, or plastic film.
In addition, from the standpoint of preventing non-image areas from being stained, a support having a hydrophilic surface is preferable, and a base material of these supports, for example, an aluminum plate or the like is subjected to a hydrophilic surface treatment as described later. Etc. can be used.

As the support applicable to the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film in which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and a conventionally known and publicly available aluminum plate can be used as appropriate.
The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.12 mm to 0.4 mm.

  Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can also be used. The roughened aluminum plate is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodization treatment to enhance the water retention and wear resistance of the surface as desired. 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, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

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

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, the lower layer and the upper recording layer are provided on a support, and an undercoat layer can be provided between the support and the lower layer, if necessary. By providing this undercoat layer, the undercoat layer between the support and the recording layer functions as a heat insulating layer, and the heat generated by the infrared laser exposure does not diffuse to the support and can be used efficiently. Therefore, there is an advantage that high sensitivity can be achieved.
Moreover, since the lower layer according to the present invention is located on the exposed surface or in the vicinity thereof even when the undercoat layer is provided, the sensitivity to the infrared laser is maintained well.
In the unexposed area, the recording layer itself that is impermeable to the alkaline developer functions as a protective layer for the undercoat layer, so that the development stability is good and the image is excellent in discrimination. In the exposed area, the components of the recording layer whose dissolution-inhibiting ability is released are quickly dissolved and dispersed in the developer. Since the undercoat layer itself, which is adjacent to the support, is made of an alkali-soluble polymer, it has good solubility in a developer, for example, even when a developer with reduced activity is used. It is considered that this undercoat layer is useful because it dissolves rapidly without the formation of a film and the like and contributes to the improvement of developability.

  Various organic compounds are used as the primer layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent Organic phosphonic acids such as naphthyl phosphonic acid, alkyl phosphonic acid, glycero phosphonic acid, methylene diphosphonic acid and ethylene diphosphonic acid, phenyl phosphoric acid which may have a substituent, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid and other organic phosphinic acids, glycine and β-alanine amino acids, and triethanolamine hydrochloric acid Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

  Furthermore, an undercoat layer containing at least one compound selected from the group of organic polymer compounds having a structural unit represented by the following formula is also preferred.

Wherein, R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group, R ¹² and R ¹³ each independently represents a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, -OR ^{14, -COOR} 15, represents a ^-CONHR 16, -COR ¹⁷ or -CN. R ¹² and R ¹³ may combine to form a ring. R ^{14 to} R ¹⁷ each independently represents an alkyl group or an aryl group, X represents a hydrogen atom, a metal atom, or NR ¹⁸ R ¹⁹ R ²⁰ R ²¹ , and R ^{18 to} R ²¹ each independently represents a hydrogen atom , An alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, or R ¹⁸ and R ¹⁹ may be bonded to form a ring, and m represents an integer of 1 to 3.

Moreover, as a suitable undercoat layer component in the present invention, there can be mentioned a polymer compound having a structural unit having an acid group and a structural unit having an onium group, as described in JP-A No. 2000-241962.
Specific examples include a copolymer of a monomer having an acid group and a monomer having an onium group.
The acid group is preferably an acid group having an acid dissociation index (pKa) of 7 or more, more preferably —COOH, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , — CONHSO ₂ — or —SO ₂ NHSO ₂ —, particularly preferably —COOH.
Specific examples of the monomer having an acid group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, and styrene having the acid group.
Preferred as the onium group is an onium group composed of Group V or Group VI atoms, more preferably an onium group composed of nitrogen, phosphorus or sulfur atoms, and particularly preferably an onium group composed of nitrogen atoms. It is a group. Specific examples of the monomer having an onium group include styrene having a substituent containing an onium group such as a methacrylate having an ammonium group in the side chain, a methacrylamide, a substituent containing an onium group such as a quaternary ammonium group, and the like. It is done.
Furthermore, compounds as described in JP-A No. 2000-108538, Japanese Patent Application No. 2002-257484, Japanese Patent Application No. 2003-78699, and the like can be used as necessary.

  These undercoat layers can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution in which the above organic compound is dissolved in the above organic solvent or a mixed solvent thereof to adsorb the above compound, and then washed and dried with water or the like to provide an undercoat layer.

In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods.
In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid.
In addition, a yellow dye can be added to the undercoat layer in order to improve the tone reproducibility of the image recording material.

The coating amount of the undercoat layer, 2 to 200 mg / ^{m 2} are suitable, and preferably from 5 to 100 mg / ^{m 2.} When the coating amount is in the above range, a sufficient effect of improving printing durability can be obtained.

<Plate making of lithographic printing plate precursor>
The planographic printing plate precursor of the present invention is image-formed by heat. That is, the alkali solubility in the heated region of the recording layer is increased and removed by development, and the ink-receptive image area (unexposed area) and the hydrophilic surface of the support are exposed by development. An image portion (exposed portion) is formed, and a lithographic printing plate is obtained.
(exposure)
The planographic printing plate precursor of the present invention is image-formed by heat. Specifically, an image is formed by exposure with a solid-state high-power infrared laser such as a semiconductor laser or a YAG laser that emits infrared light having a wavelength of 700 to 1200 nm.
Direct image-like recording by a thermal recording head or the like, high-illuminance flash exposure such as a xenon discharge lamp, or infrared lamp exposure can also be used.
The output of the infrared laser is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec, and the energy applied to the lithographic printing plate precursor is preferably 10 to 500 mJ / cm ² .

〔developing〕
In the present invention, the lithographic printing plate precursor is preferably developed with an alkaline aqueous solution having a pH of 12 or higher that does not substantially contain an organic solvent. Here, “substantially free of organic solvent” means that it does not contain an organic solvent to the extent of causing inconvenience in terms of environmental health, safety, workability, etc. The ratio of the organic solvent in the developer is 0.5% by weight or less, preferably 0.3% by weight or less, and most preferably not contained at all. Moreover, although pH is 12.0 or more, More preferably, it is 12.0-14.0.
A known alkaline aqueous solution can be used as the developer (hereinafter referred to as a developer including a replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

  Among the above alkaline aqueous solutions, one of the developing solutions that exert the effect according to the present invention is a so-called one containing an alkali silicate as a base or containing an alkali silicate by mixing a silicon compound with a base. Another more preferable developer, which is an aqueous solution called “silicate developer” having a pH of 12 or more, does not contain an alkali silicate, and contains a non-reducing sugar (an organic compound having a buffering action) and a base. Silicate developer ".

In the former, the aqueous solution of alkali metal silicate is a ratio of silicon oxide SiO ₂ and alkali metal oxide M ₂ O which is a component of silicate (generally expressed as a molar ratio of [SiO ₂ ] / [M ₂ O]. ) And the density, the developability can be adjusted. For example, as disclosed in JP-A No. 54-62004, the SiO ₂ / Na ₂ O molar ratio is 1.0 to 1.5 (that is, [SiO ₂ ] / [Na ₂ O] is 1.0 to 1.5), and an aqueous solution of sodium silicate having a SiO ₂ content of 1 to 4% by mass is disclosed in JP-B-57-7427. As described, [SiO ₂ ] / [M] is 0.5 to 0.75 (ie, [SiO ₂ ] / [M ₂ O] is 1.0 to 1.5), and SiO ₂ The total alkali gold in which the concentration of the developer is 1 to 4% by mass and the developer is present therein And the gram atom based containing potassium at least 20%, aqueous solution of an alkali metal silicate is preferably used.

  In addition, a so-called “non-silicate developer” which does not contain an alkali silicate and contains a non-reducing sugar and a base is more preferable for application to the development of a lithographic printing plate precursor according to the present invention. When the development of the planographic printing plate precursor is performed using this developer, the surface of the positive recording layer is not deteriorated, and the inking property of the positive recording layer can be maintained in a good state. . In addition, the lithographic printing plate precursor generally has a narrow development latitude and a large change in the image line width due to the developer pH, but the non-silicate developer contains a non-reducing sugar having a buffering property that suppresses fluctuations in pH. Therefore, it is more advantageous than the case where a developing processing solution containing silicate is used. Furthermore, since non-reducing sugars are less likely to contaminate conductivity sensors, pH sensors and the like for controlling liquid activity compared to silicates, non-silicate developers are advantageous in this respect as well. Further, the effect of improving discrimination is remarkable. This is presumably because the contact (penetration) with the developer which is important in the present invention is mild, and the difference between the exposed and unexposed areas is likely to occur.

  The non-reducing sugar is a saccharide that does not have a free aldehyde group or a ketone group and does not exhibit reducibility, and is a trehalose-type oligosaccharide in which reducing groups are bonded to each other. And sugar alcohols reduced by hydrogenation of saccharides and sugars, both of which can be suitably used in the present invention. In the present invention, non-reducing sugars described in JP-A-8-305039 can be preferably used.

  Examples of the trehalose type oligosaccharides include saccharose and trehalose. Examples of the glycoside include alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, zulsiit, allozulcit and the like. . Further, maltitol hydrogenated to disaccharide maltose, reduced form obtained by hydrogenation of oligosaccharide (reduced water candy), and the like are preferable. Among these non-reducing sugars, trehalose-type oligosaccharides and sugar alcohols are preferable, and among them, D-sorbitol, saccharose, reduced syrup, etc. are preferable in that they have a buffering action in an appropriate pH region and are inexpensive.

  These non-reducing sugars may be used alone or in combination of two or more. The content of the non-reducing sugar in the non-silicate developer is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass. If the content is less than 0.1% by mass, a sufficient buffering effect tends to be not obtained, and if it exceeds 30% by mass, it is difficult to achieve high concentration and the cost tends to increase.

  Examples of the base used in combination with the non-reducing sugar include known alkali agents such as inorganic alkali agents and organic alkali agents. Examples of the inorganic alkaline agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, Examples thereof include sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate.

Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanol. Examples include amine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine.
The said base may be used individually by 1 type, and may use 2 or more types together. Among these bases, sodium hydroxide and potassium hydroxide are preferable. In the present invention, as the non-silicate developer, a non-reducing sugar alkali metal salt as a main component can be used instead of the non-reducing sugar and the base.

  In addition, an alkaline buffer composed of a weak acid other than the non-reducing sugar and a strong base can be used in combination with the non-silicate developer. The weak acid preferably has a dissociation constant (pKa) of 10.0 to 13.2, and can be selected from, for example, those described in Ionization Constants of Organic Acids Solution issued by Pergmon Press.

  Specifically, alcohols such as 2,2,3,3-tetrafluoropropanol-1, trifluoroethanol, and trichloroethanol, pyridine-2-aldehyde (, aldehydes such as pyridine-4-aldehyde (such as salicylic acid, 3-hydroxy-2-naphthoic acid, catechol, gallic acid, sulfosalicylic acid, 3,4-dihydroxysulfonic acid, 3,4-dihydroxybenzoic acid, hydroquinone (11.56), pyrogallol, o-, m-, p -Compounds having a phenolic hydroxyl group such as cresol, resorsonol, oximes such as acetoxime, 2-hydroxybenzaldehyde oxime, dimethylglyoxime, ethanediamide dioxime, acetophenone oxime, adenosine, inosine, guanine, cytosine, hypoxanthine, chitosan Nucleic acid-related substances such as Nchin, other, diethylaminomethyl acid, benzimidazole, and the like barbituric acid is preferably exemplified.

  Various surfactants and organic solvents can be added to the developer as necessary for the purpose of promoting or suppressing developability, dispersing development residue, or improving ink affinity of the printing plate image area. As the surfactant, anionic, cationic, nonionic and amphoteric surfactants are preferable. Furthermore, in the developer, if necessary, a reducing agent such as sodium salt or potassium salt of inorganic acid such as hydroquinone, resorcin, sulfurous acid, or bisulfite, and further organic carboxylic acid, antifoaming agent, water softener, etc. Can be added.

  The lithographic printing plate developed using the developer and the replenisher is post-treated with a desensitizing solution containing washing water, a rinsing solution containing a surfactant or the like, gum arabic or a starch derivative. As post-processing, these processes can be used in various combinations.

Further, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer, so that a large amount of the developer can be obtained without replacing the developer in the developer tank for a long time. It is known that PS plates can be processed. This replenishment method is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developer and replenisher as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving ink affinity of the printing plate image area.
Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added.
The printing plate developed using the developer and the replenisher is post-treated with water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment of the printing plate precursor according to the present invention, these treatments can be used in various combinations.

  In recent years, automatic developing machines for printing plates have been widely used in the plate making and printing industries in order to rationalize and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting the printing plate, each processing liquid tank and a spray device, and each pumped up by a pump while transporting the exposed printing plate horizontally. A developing solution is sprayed from a spray nozzle. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll in a processing liquid tank filled with the processing liquid. In such automatic processing, each processing solution can be processed while being supplemented with a replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can also be applied.

  In the lithographic printing plate precursor according to the present invention, image portions unnecessary for the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, film edge traces of the original film). Etc.), the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. As described in JP-A-59-174842, a method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to make a lithographic printing plate with a higher printing durability, if desired, Burning process is performed.
In the case of burning a lithographic printing plate, the preparation as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859 and JP-A-61-159655 is performed before burning. It is preferable to treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method of applying the printing plate by dipping in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting liquid is dried if necessary and then heated to a high temperature with a burning processor (for example, a burning processor sold by FUJIFILM Corporation: “BP-1300”). . In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

  In the present invention, as described above, (A) the lower layer containing the specific polymer and (B) the specific polymer and (C) the upper recording layer containing the photothermal conversion agent are provided adjacent to each other. Since the (A) specific polymer contained has a partial structure capable of forming a crosslinked structure, this burning treatment not only improves the film properties itself but also the specific functional groups of the components contained in the adjacent upper recording layer. In order to form a cross-linked structure with each other, the adhesion between the lower layer and the upper recording layer is improved, and the printing durability is remarkably improved.

The lithographic printing plate that has been burned can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound is used. In such a case, a so-called desensitizing treatment such as gumming can be omitted.
The lithographic printing plate precursor of the present invention becomes a lithographic printing plate by such treatment. This planographic printing plate is applied to an offset printing machine or the like and used for printing a large number of sheets. The lithographic printing plate precursor of the present invention has the advantages of excellent chemical resistance and printing durability of the image area, wide development latitude, and excellent image reproducibility.

EXAMPLES Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.

(Synthesis Example 1)
<(A) Synthesis of Specific Polymer 1>
(A) The specific polymer 1 contains N-phenylmaleimide 14.97 g (30 mol%), methacrylamide 3.68 g (15 mol%), methacrylic acid 4.96 g (20 mol%), and Rohamere having the following structure. It was synthesized by a conventional method using 6.84-0 (Degussa) 22.84 g (20 mol%) and N-hydroxymethylmethacrylamide 8.29 g (15 mol%). The yield was 36.26 g, and the yield was 71%. The weight average molecular weight of the obtained (A) specific polymer 1 measured by the GPC method was 55000.

(Synthesis Example 2)
<(A) Synthesis of specific polymer 2>
(A) The specific polymer 2 contains 32.39 g (41.5 mol%) of N-phenylmaleimide, 8.15 g (21 mol%) of methacrylic acid, and 32.43 g (37 of N-hydroxymethylmethacrylamide) as raw materials. .5 mol%) was synthesized by a conventional method. The yield was 58.21 g, and the yield was 97%. The weight average molecular weight of the obtained (A) specific polymer 2 was 60000.

(Synthesis Example 3)
<Synthesis of (AC) Comparative Polymer C1>
(AC) Comparative polymer C1 is composed of N-phenylmaleimide 14.03 g (30 mol%), methacrylamide 3.45 g (15 mol%), methacrylic acid 4.65 g (20 mol%), and Rohamere having the above structure. It was synthesized according to a conventional method using 21.41 g (20 mol%) of 6852-0 (Degussa) and 7.18 g (15 mol%) of N- (p-hydroxyphenyl) methacrylamide. The yield was 30.43 g, and the yield was 59%. This polymer C1 is a comparative polymer having not a alcoholic hydroxyl group as in the present invention but a phenolic hydroxyl group in the side chain. The resulting comparative specific polymer AC1 had a weight average molecular weight of 50,000.

(Synthesis Example 4)
<(B) Synthesis of specific polymer 1>
(B) The specific polymer 1 was synthesized as follows.
A three-necked round bottom flask equipped with a stirrer was charged with 150 g of methyl ethyl ketone and 10 g of dimethylacetamide in a nitrogen atmosphere and heated to 80 ° C. Then, 6.6 g of methacrylate 46.55 g N- (4-carboxyphenyl) -maleimide was added to this solvent mixed solution and dissolved. Thereafter, the mixture was gently refluxed for 15 minutes in a nitrogen atmosphere, and 0.12 g of AIBN was added to lower the nitrogen gas pressure. After reacting for 1 hour, 0.7 g of AIBN (azobisbutyronitrile) was further added and reacted at 85 ° C. for 3 hours. To this solution, 600 ml of petroleum ether (Washbenzin 135/180) was added and precipitated. The precipitate was filtered off and dried in a vacuum oven at 40 ° C. to obtain (B) specific polymer-1. The weight average molecular weight measured by GPC method of the obtained (B) specific polymer was 45000.

[Examples 1 and 2]
(Production of support)
An aluminum plate (material: JIS A 1050) with a thickness of 0.3 mm is etched for 10 seconds at a caustic soda concentration of 30 g / l, an aluminum ion concentration of 10 g / l, and a liquid temperature of 60 ° C., washed with running water, and washed with 10 g / l nitric acid. After neutralizing and washing with water. Using an alternating waveform current of sine wave under the condition of applied voltage Va = 20 V, an electric current of 400 C / dm ² in an aqueous solution having a hydrogen chloride concentration of 15 g / l, an aluminum ion concentration of 10 g / l, and a liquid temperature of 30 ° C. Electrochemical roughening treatment was carried out in an amount and washed with water. Next, etching treatment was performed for 10 seconds at a caustic soda concentration of 30 g / l, an aluminum ion concentration of 10 g / l, and a liquid temperature of 40 ° C., and washed with running water. Next, desmut treatment was performed in a sulfuric acid aqueous solution having a sulfuric acid concentration of 15% by mass and a liquid temperature of 30 ° C., followed by washing with water. Furthermore, in a 10% by mass sulfuric acid aqueous solution at a liquid temperature of 20 ° C., an anodizing treatment was performed so that both of the anodized films corresponded to 2.5 g / m ² under a condition of a current density of 6 A / dm ² by direct current. , Dried. Then, it processed for 10 second at 30 degreeC with the sodium silicate 1.0 mass% aqueous solution, and produced the support body (a) which carried out the hydrophilic process.
When the center line average roughness (Ra) of the support (a) was measured using a needle having a diameter of 2 μm, it was 0.48 μm.

(Formation of undercoat layer)
The following undercoat liquid was applied to the support (a) thus obtained, and dried at 80 ° C. for 30 seconds to provide an undercoat layer. The dry coating amount of the undercoat layer was 17 mg / m ² .

(Undercoat liquid composition)
・ The following compound 0.3g
・ Methanol 100g
・ Water 1g

[Formation of recording layer]
After applying the lower layer coating solution 1 having the following composition to the support (a) having the undercoat layer obtained as described above with a bar coater so that the coating amount becomes 0.85 g / m ² , the temperature is 160 ° C. The substrate was dried for 44 seconds and immediately cooled with cold air of 17 to 20 ° C. until the temperature of the support became 35 ° C.
After that, the upper recording layer coating solution 1 having the following composition was applied to the surface of the formed lower layer with a bar coater so that the coating amount was 0.22 g / m ² , and then dried at 148 ° C. for 25 minutes, and further 20 to The plate was gradually cooled with a wind of 26 ° C. to obtain a planographic printing plate precursor of the example.

[Lower layer coating solution 1]
-(A) Specific polymer (compound of Table 1) 1.8g
Novolak resin A (m / p-cresol (6/4), weight average molecular weight;
7,000, unreacted cresol; 0.3% by weight) 0.2 g
-Cyanine dye A ((C) photothermal conversion agent: the following structure) 0.134 g
・ 4,4'-bishydroxyphenylsulfone 0.126g
・ Tetrahydrophthalic anhydride 0.190g
・ 0.008 g of p-toluenesulfonic acid
・ 3-Methoxy-4-diazodiphenylamine
Hexafluorophosphate 0.032g
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalene sulfone 0.081 g
・ Polymer-1 (the following structure, Mw:) 0.035 g
・ Γ-Butyrolactone 52.40g
・ 1-methoxy-2-propanol 17.60 g

[Upper recording layer coating solution 1]
・ (B) Specific polymer 0.0468g
((B) Specific polymer 1 obtained in Synthesis Example 4)
Novolak resin B (m / p-cresol (6/4), weight average molecular weight; 5,000,
Unreacted cresol; 0.8% by weight) 0.3479 g
・ Cyanine dye A (the above structure) 0.0192 g
・ Polymer 1 (the above structure) 0.015 g
-Polymer 2 (the following structure) 0.00328g
・ Methyl ethyl ketone 13.07g
1-methoxy-2-propanol 6.79g

  In addition, (A) specific polymer and (B) specific polymer in this invention of following Table 1 were obtained in the said synthesis example, (A) specific polymer 1- (A) specific polymer 2, (B) Specific polymer 1.

[Comparative Example 1]
In the upper recording layer coating solution 1 used in Example 1, the lithographic printing of Comparative Example 1 was performed in the same manner as in Example 1 except that (B) the same amount of novolak resin B was used instead of the specific polymer 1. I got the original version.
[Comparative Example 2]
In the lower layer coating solution 1 used in Example 1, (A) In place of the specific polymer 1, the same amount of the comparative polymer AC1 obtained in Synthesis Example 3 was used. A lithographic printing plate precursor was obtained.
[Comparative Example 3]
A lithographic printing plate precursor of Comparative Example 3 was obtained in the same manner except that (A) the same amount of novolak resin A was used in place of the specific polymer 1 in the lower layer coating solution 1 used in Example 1.
[Comparative Example 4]
In the upper recording layer coating solution 1 used in Example 1, the same amount of novolak resin B was used instead of (B) the specific polymer 1, and in the lower layer coating solution 1, (A) instead of the specific polymer 1, A lithographic printing plate precursor of Comparative Example 4 was obtained in the same manner except that the same amount of novolak resin A was used.

[Evaluation of planographic printing plate precursor]
(Evaluation of printing durability)
The lithographic printing plate precursors of the examples and comparative examples were drawn on a test pattern in the form of an image by changing the exposure energy with a Trend setter manufactured by Creo. After that, the lithographic printing plate developed with Fuji Photo Film Co., Ltd. developer DT-2 (diluted to have an electrical conductivity of 43 mS / cm) was continuously used using a printing machine Lithlon made by Komori Corporation. Printed. At this time, the number of sheets that can be printed while maintaining a sufficient ink density was measured visually to evaluate the printing durability. The larger the number, the better the printing durability. The results are shown in Table 1 below.

(Evaluation of chemical resistance)
The lithographic printing plate precursors of Examples and Comparative Examples were exposed / developed and printed in the same manner as in the evaluation of printing durability. At this time, every time 5,000 sheets were printed, a process of wiping the plate surface with a cleaner (manufactured by Fuji Photo Film Co., Ltd., multi-cleaner) was added to evaluate chemical resistance. The larger the number, the better the chemical resistance. The results are shown in Table 1 below.

(Evaluation of burning durability)
The lithographic printing plate precursors of Examples and Comparative Examples were exposed and developed in the same manner as in the evaluation of printing durability, and then a surface-adjusting solution BC-7 manufactured by Fuji Film Co., Ltd. was applied with a sponge, and then Fuji Film was used. (stock)
Burning processor manufactured: BP-1300 was heated at 260 ° C. for 6 minutes to perform the burning treatment. This lithographic printing plate was printed and evaluated in the same manner as in the evaluation of printing durability. The results are shown in Table 1 below.
(Scratch resistance evaluation)
The heat-sensitive lithographic printing plates of Examples 1 and 2 and Comparative Example 1 were rubbed 15 times with Abrazer felt CS5 under a load of 250 g using a rotary ablation tester (manufactured by TOYOSEIKI).
Then, using a Fuji Photo Film Co., Ltd. PS processor 940HII charged with Fuji Photo Film Co., Ltd. DT-2 (diluted with water to a conductivity of 43 mS / cm), the liquid temperature was kept at 30 degrees, Developed with a development time of 12 s. The scratch resistance was evaluated according to the following criteria.

<Evaluation criteria for scratch resistance>
○: The optical density of the photosensitive film in the rubbed portion was not changed at all. Δ: The optical density drop of the photosensitive film in the rubbed part was slightly observed visually. Is less than 2/3 of the non-friction part

As is apparent from Table 1, the lithographic printing plate precursors of Examples 1 and 2 according to the present invention are excellent not only in normal printing durability but also in chemical resistance and burning printing durability, and scratch resistance. It turns out that property is also favorable.
On the other hand, Comparative Example 1 in which the upper recording layer does not contain (B) the specific polymer is inferior in surface scratch resistance and the lower layer does not contain (A) the specific polymer even if it has a multi-layered recording layer. , 3 had good printing durability, but the burning printing durability was insufficient, and the scratch resistance of the surface was slightly inferior. Further, Comparative Example 4 using the novolak resin A and the novolak resin B in place of the (A) specific polymer and (B) specific polymer, respectively, was remarkably inferior in both printing durability and chemical resistance.

Claims (3)

On the support, (A) a lower layer containing a polymer compound having a structural unit represented by the following general formula (I), and (B) a polymer having a structural unit represented by the following general formula (II) A lithographic printing plate precursor comprising a compound and (C) a recording layer containing a compound that absorbs light and generates heat.

[In the general formula (I), R ¹ represents a hydrogen atom or a methyl group. R ² represents an alkylene group having 1 to 4 carbon atoms. ]

[In General Formula (II), X ¹ represents an alkylene group, an arylene group, an arylene group, and a divalent linking group including at least one of them. n represents an integer of 1 to 3. ]   The lithographic printing plate according to claim 1, wherein the content of the polymer compound having the structural unit represented by (A) the general formula (I) is 20% by mass to 95% by mass in the total solid content constituting the lower layer. Original edition.   2. The planographic plate according to claim 1, wherein the content of the polymer compound having the structural unit represented by (B) the general formula (II) is 3% by mass to 40% by mass in the total solid content constituting the upper recording layer. A printing plate master.