WO2018199316A1 - Curable composition, planographic printing master plate, method for manufacturing planographic printing plate, and salt compound - Google Patents

Abstract

Provided are a durable composition containing a salt compound that comprises organic borate anions expressed by a specific structure and (B) counter cations, a planographic printing master plate having an image recording layer that contains the curable composition, a method for manufacturing a planographic printing plate in which the planographic printing master plate is used, and a salt compound used in the image recording layer of the planographic printing master plate.

Description

Curable composition, lithographic printing plate precursor, method of preparing lithographic printing plate, and salt compound

The present invention relates to a curable composition, a lithographic printing plate precursor, a method of preparing a lithographic printing plate, and a salt compound.

A curable composition, in particular, a photocurable composition is a composition having a property of curing an irradiated part by irradiation of light, and a coating liquid formed by appropriately dissolving or dispersing this composition in a solvent is used. The photocurable film can be formed by coating on a suitable support and drying to form an image forming material. Examples of the image forming material include an image forming material utilizing curing by image exposure such as a lithographic printing plate precursor, a printed wiring board, a color filter, a photomask and the like.
Hereinafter, a lithographic printing plate precursor will be described as an example.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink during the printing process and a hydrophilic non-image area that receives dampening water. In lithographic printing, utilizing the property that water and oil-based ink repel each other, the lipophilic image area of the lithographic printing plate is an ink receiving area, the hydrophilic non-image area is a dampening water receiving area (ink non-receiving area In the method, the difference in the adhesion of the ink is produced on the surface of the lithographic printing plate, the ink is deposited only in the image area, and then the ink is transferred to a printing material such as paper for printing.

In the plate making process for producing a lithographic printing plate from a lithographic printing plate precursor, image exposure is currently performed by the CTP (computer-to-plate) technique. That is, the image exposure is performed by scanning exposure etc. directly on the lithographic printing plate precursor using a laser or a laser diode without interposing a lith film.

With regard to plate-making of lithographic printing plate precursors, environmental concerns regarding waste liquids associated with wet processing such as development processing are highlighted from the growing interest in the global environment, and along with this, development processing is simplified or eliminated. Is directed. As one of the simple development processes, a method called "on-machine development" has been proposed. On-press development is a method in which the lithographic printing plate precursor is subjected to image exposure and then is not subjected to conventional development processing, and is attached as it is to a printing machine to remove non-image areas of the image recording layer at an early stage of ordinary printing process. .

The lithographic printing plate precursor usually has an image recording layer on a support such as an aluminum plate. In the case of a negative type image recording layer, the image recording layer has a function of curing the exposed portion by image exposure to form an image portion. Therefore, the image recording layer contains components for forming an image by image exposure. As one component contained in an image recording layer, the photoinitiator which generate | occur | produces a radical by exposure is mentioned.
As the photopolymerization initiator contained in the image recording layer, a salt compound composed of onium such as iodonium and sulfonium and inorganic or organic anion as a counter anion is used. As inorganic or organic anions as counter anions, sulfonate anions, carboxylate anions, tetrafluoroborate anions, hexafluorophosphate anions, p-toluenesulfonate anions, tosylate anions, etc. are known. For example, Patent Document 1 describes a radiation-sensitive composition containing, as a photopolymerization initiator, a salt compound composed of a diaryliodonium cation of a specific structure and a borate anion of a specific structure.

As a pre-process of attaching the lithographic printing plate to the printing machine, generally, an operation (plate inspection) to inspect or identify the image on the lithographic printing plate is performed whether the lithographic printing plate is intended for image recording. In particular, in multi-color printing, it is important in printing operations to be able to determine registration marks (register marks) which are registration marks.

In a lithographic printing plate precursor involving a conventional development processing step, a colored image can be obtained by development processing by coloring the image recording layer, so that the image can be easily confirmed before mounting the lithographic printing plate in a printing machine it can.
However, in the case of an on-press development type or non-processing (non-development) type lithographic printing plate precursor without a conventional development processing step, the image on the lithographic printing plate precursor is confirmed at the stage of mounting the lithographic printing plate precursor on a printing machine It is difficult, and it is not possible to print enough. Therefore, in an on-press development type or non-treatment (non-development) type planographic printing plate precursor, a means for confirming an image at the exposed stage without adversely affecting on-press development, ie, the exposed area is colored or decolored It is required that a so-called printout image be formed.

As a means for forming a printout image, a photoacid generator and an acid chromogenic dye (leuco dye) are contained in the image recording layer, and the acid chromogenic dye is produced by the action of an acid generated from the photoacid generator upon image exposure. There is known a method of forming a colored image by causing

Furthermore, it is desirable that the lithographic printing plate precursor has high heat aging stability. When the heat aging stability is low, dark polymerization proceeds in the lithographic printing plate precursor due to heat aging, and as a result, the on-press developability is reduced. In addition, in the case of a lithographic printing plate precursor containing an acid color-forming dye such as leuco dye, there is a problem that ring-like coloration occurs upon heat aging. Therefore, the heat stability over time is an important characteristic for a lithographic printing plate precursor.

Japanese Patent Application Publication No. 2009-538446

An object of the present invention is to provide a curable composition which has high heat aging stability and cures well by light irradiation.
Another object of the present invention is to provide a lithographic printing plate precursor capable of producing a lithographic printing plate having high thermal aging stability, excellent on-press developability, and excellent printing durability.
Still another object of the present invention is to provide a lithographic printing plate precursor capable of producing a lithographic printing plate having high thermal stability over time, excellent in plate inspection properties and on-press developability, and having excellent printing durability. It is to be.
Still another object of the present invention is to provide a method of preparing a lithographic printing plate using the above lithographic printing plate precursor.

The means for solving the above problems are described below.
(1)
A curable composition comprising (A) an organic borate anion represented by the following formula (I), and (B) a salt compound comprising a counter cation.

In formula (I), R ₁ to R _{4, which} may be the same or different, each independently represents a monovalent substituent, or two or more of R ₁ to R ₄ are bonded to each other to form boron The ring structure may be formed together with the atom, the oxygen atom and Y. Y each independently represents -O- or -NR _5- , and R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group Represents
(2)
The curable composition as described in (1) whose said organic borate anion is an organic borate anion represented by following formula (II).

In the formula (II), Cy 1 and Cy 2, which may be the same or different, each represents a ring structure formed together with a boron atom, an oxygen atom and Y, and Y independently represents —O— or —NR ₅ And R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group.
(3)
The curable composition as described in (1) or (2) whose said organic borate anion is an organic borate anion represented by following formula (III).

In formula (III), R ₇ to R ₁₄ may be the same or different and each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, an arylcarbonyl group, an alkyl ester group, or an alkenyl group. Represents an ester group. Adjacent two of R ₇ to R ₁₄ may be bonded to each other to form a ring structure.
(4)
The curable composition according to any one of (1) to (3), wherein the counter cation is a diaryliodonium cation or a triarylsulfonium cation. (5)
The curable composition according to any one of (1) to (3), wherein the counter cation is an alkali metal ion, an alkaline earth metal ion, or an organic cation having a charge on a nitrogen atom.
(6)
The curable composition according to any one of (1) to (3), wherein the counter cation is a counter cation in a cyanine dye.
(7)
The curable composition according to any one of (1) to (6), further comprising a polymerizable compound and an infrared absorber.
(8)
The curable composition as described in (7) whose said infrared rays absorber is a cyanine pigment.
(9)
The curable composition according to any one of (1) to (8), further comprising an acid color former.
(10)
The curable composition according to any one of (1) to (9), further comprising polymer particles. (11)
The curable composition according to any one of (1) to (10), further comprising a binder polymer.
(12)
A curable composition for a lithographic printing plate as described in any one of (1) to (11).
(13)
A lithographic printing plate precursor having an image recording layer containing the curable composition according to any one of (1) to (12) on a support.
(14)
The lithographic printing plate precursor as described in (13) above, which has a protective layer on the image recording layer.
(15)
The step of imagewise exposing the lithographic printing plate precursor as described in (13) or (14), and removing the unexposed area of the image recording layer by at least one selected from printing ink and dampening water on a printing press And a process for producing a lithographic printing plate.
(16)
A salt compound comprising an organic borate anion and a counter cation, wherein the organic borate anion is an organic borate anion represented by the following formula (II), and the counter cation is a diaryliodonium cation or a triarylsulfonium cation Salt compound.

In the formula (II), Cy 1 and Cy 2, which may be the same or different, each represents a ring structure formed together with a boron atom, an oxygen atom and Y, and Y independently represents —O— or —NR ₅ And R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group.

According to the present invention, it is possible to provide a curable composition which has high heat aging stability and cures well by light irradiation.
Further, according to the present invention, it is possible to provide a lithographic printing plate precursor capable of producing a lithographic printing plate having high thermal temporal stability, excellent in on-press developability, and excellent printing durability.
Furthermore, according to the present invention, there is provided a lithographic printing plate precursor capable of producing a lithographic printing plate having high thermal stability over time, being excellent in plate inspection properties and on-press developability, and having excellent printing durability. be able to.
Further, according to the present invention, it is possible to provide a method of preparing a lithographic printing plate using the above-mentioned lithographic printing plate precursor.

Hereinafter, the present invention will be described in detail.
In the present specification, with regard to the notation of a group in a compound represented by the formula, when no substitution or no substitution is described, the group may further have a substituent, unless otherwise specified. Not only unsubstituted groups but also groups having substituents. For example, in the formula, if "R represents an alkyl group, an aryl group or a heterocyclic group", "R represents an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, an unsubstituted group. And "representing a heterocyclic group or a substituted heterocyclic group".
In the present specification, "(meth) acrylic" means both or either of acrylic and methacrylic, and "(meth) acrylate" means both or any of acrylate and methacrylate.
In the present specification, mass average molecular weights (Mw) are gel permeation chromatography (columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (all are trade names manufactured by Tosoh Corp.), unless otherwise noted. GPC) It is a molecular weight which is detected by a differential refractometer using THF (tetrahydrofuran) as a solvent and a polystyrene as a standard substance by an analyzer.

[Curable composition]
The curable composition of the present invention contains (A) an organic borate anion represented by the following formula (I) and (B) a salt compound comprising a counter cation.

In formula (I), R ₁ to R _{4, which} may be the same or different, each independently represents a monovalent substituent, or two or more of R ₁ to R ₄ are bonded to each other to form boron The ring structure may be formed together with the atom, the oxygen atom and Y. Y represents -O- or -NR _5- , and R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group.

The salt compound (hereinafter, also simply referred to as “specific compound”) contained in the curable composition of the present invention (hereinafter also simply referred to as “composition”) is an organic borate anion represented by the formula (I) and a counter cation And a salt compound in which

[Organic borate anion represented by formula (I)]
The organic borate anion represented by the formula (I) can be represented by a plurality of resonant structural formulas according to the electronic configuration as in the general anion, but in the present specification, as shown below, on the boron atom It describes using the resonant structural formula which has a negative charge.

Examples of the monovalent substituent represented by R ₁ , R ₂ , R ₃ or R ₄ in the formula (I) include an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group and a heterocyclic group. Can be mentioned.

The alkyl group represented by R ₁ , R ₂ , R ₃ or R ₄ is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and alkyl having 1 to 4 carbon atoms More preferable. The alkyl group may be linear or branched. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, ter-butyl, pentyl, isopentyl, hexyl, octyl, ter-octyl Groups, nonyl groups, decyl groups, dodecyl groups and the like. The alkyl group may have a substituent, and examples of the substituent include an alkoxy group, an aryloxy group, an aryl group, an alkoxycarbonyl group, a cyano group and the like.

The cycloalkyl group represented by R ₁ , R ₂ , R ₃ or R ₄ is preferably a cycloalkyl group having a carbon number of 3 to 8 and more preferably a cycloalkyl group having a carbon number of 3 to 6. Examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group. The cycloalkyl group may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, an alkylcarbonyl group and the like.

The alkenyl group represented by R ₁ , R ₂ , R ₃ or R ₄ is preferably an alkenyl group having 2 to 12 carbon atoms, and more preferably an alkenyl group having 2 to 6 carbon atoms. The alkenyl group may be linear or branched. Examples of alkenyl groups include ethenyl group, propenyl group and the like. The alkenyl group may have a substituent, and examples of the substituent include an alkoxy group, an alkylcarbonyl group and the like.

The alkynyl group represented by R ₁ , R ₂ , R ₃ or R ₄ is preferably an alkynyl group having 2 to 12 carbon atoms, and more preferably an alkynyl group having 2 to 6 carbon atoms. The alkynyl group may be linear or branched. Examples of the alkynyl group include ethynyl group, propynyl group and the like. The alkynyl group may have a substituent, and examples of the substituent include an alkoxy group, an alkylcarbonyl group and the like.

The aryl group represented by R ₁ , R ₂ , R ₃ or R ₄ is preferably an aryl group having 6 to 20 carbon atoms, and more preferably an aryl group having 6 to 10 carbon atoms. Examples of the aryl group include phenyl group and naphthyl group. The aryl group may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an aryl group, an alkoxycarbonyl group, a cyano group, a halogen atom and the like.

The heterocyclic group represented by R ₁ , R ₂ , R ₃ or R ₄ is a group formed from a heterocyclic ring containing at least one hetero atom selected from an oxygen atom, a sulfur atom and a nitrogen atom. The heterocyclic ring is preferably a 5- to 8-membered ring, more preferably a 5- or 6-membered ring. The heterocyclic group may be saturated or unsaturated. Examples of the heterocyclic group include pyridyl group, pyrimidyl group, furanyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, indolyl group, quinolinyl group, oxadiazolyl group, benzoxazolyl group and the like. . The heterocyclic group may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, an alkylcarbonyl group and the like.

In formula (I), two or more of R ₁ to R ₄ may be bonded to each other to form a ring structure together with a boron atom, an oxygen atom and Y, or may not form a ring structure. The ring structure to be formed is preferably a 5- or 6-membered ring structure. The ring structure to be formed may have a substituent and may have a fused ring. Examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an aryl group, an alkoxycarbonyl group, a cyano group, a halogen atom and the like. The fused ring includes hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring and the like.

In formula (I), Y represents -O- or -NR _5- , and R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group Represents a group.
The alkyl carbonyl group, the aryl carbonyl group, the alkyl sulfonyl group, the aryl sulfonyl group, the alkyl group and aryl group in the alkoxycarbonyl group, and the aryl group represented by R ₅ are the alkyl group and aryl group in the above R ₁ to R ₄ The statement regarding can be incorporated.
The heteroaryl group represented by R ₅ is a group formed from an aromatic heterocycle containing at least one hetero atom selected from an oxygen atom, a sulfur atom and a nitrogen atom. The aromatic heterocyclic ring is preferably a 5- to 8-membered ring, more preferably a 5- or 6-membered ring. Examples of heteroaryl groups include groups derived from heteroaryl rings such as pyridine, quinoline, quinoxaline, thiazole, benzothiazole, oxazole, imidazole, benzimidazole, pyrazole, indazole, triazole, benzotriazole, thiophene and the like.

The organic borate anion represented by the formula (I) is preferably _one in which two or more of R ₁ to R ₄ in the above formula (I) are bonded to each other to form a ring structure with a boron atom, an oxygen atom and Y. .
As the organic borate anion having such a ring structure, an organic borate anion represented by the following formula (II) is preferable.

In the formula (II), Cy 1 and Cy 2, which may be the same or different, each represents a ring structure formed together with a boron atom, an oxygen atom and Y, and Y independently represents —O— or —NR ₅ And R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group.

In the formula (II), the atomic chain constituting the ring structure represented by Cy1 or Cy2 is, for example, -O-C-C-O-, -O-C-C-C-O-, -O-C It is represented by —C—NR ₅ —, —O—C—C—C—NR ₅ —. Here, both —O— or —NR ₅ — at both ends are directly bonded to the boron atom. The carbon atom constituting the ring structure may have a substituent, and examples thereof include an oxy group (= O), an alkyl group and an aryl group. Also, two adjacent carbon atoms may be fused by a hydrocarbon ring or a heterocyclic ring. The hydrocarbon ring or heterocyclic ring fused to two adjacent carbon atoms may be a saturated ring or an unsaturated ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring and a quinoxaline ring. The hydrocarbon ring or the heterocyclic ring may have a substituent, and examples of the substituent include an alkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, an aryl group, an arylcarbonyl group, an alkyl ester group, and an alkenyl group. An ester group, a cyano group, a halogen atom etc. are mentioned.

In formula (II), Y is preferably -O-. Examples of the ring structure represented by Cy1 or Cy2 include a ring structure formed from catechol, salicylic acid, an oxalic acid derivative and a central atom B, and the like.

The ring structure represented by Cy1 is a group consisting of an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, and a group having a sulfoneimide structure The aromatic ring having at least one selected group is preferably not fused, and the ring structure represented by Cy2 is an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group Preferably, the aromatic ring is not fused with an aromatic ring having at least one group selected from the group consisting of a group having a sulfonamide structure and a group having a sulfonimide structure.
The ring structure represented by Cy1 is preferably not fused with a pyridine ring, and the ring structure represented by Cy2 is preferably not fused with a pyridine ring.

In at least one group selected from the group consisting of an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, and a group having a sulfoneimide structure, an alkylamide As for the alkyl group in the group and the alkyl group in the alkylurea group, the description of the alkyl group in R ₁ to R ₄ can be incorporated.

In at least one group selected from the group consisting of an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, and a group having a sulfoneimide structure, an alkenylamide As for the alkenyl group in the group, the description of the alkenyl group in R ₁ to R ₄ above can be incorporated.

In at least one group selected from the group consisting of an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, and a group having a sulfoneimide structure, an arylamide As for the aryl group in the group and the aryl group in the aryl urea group, the description of the aryl group in R ₁ to R ₄ above can be incorporated.

In at least one group selected from the group consisting of the above-mentioned groups consisting of an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a sulfonamide structure, and a group having a sulfoneimide structure The sulfonamide structure in the group having a structure represents the following structure. In the following structure, * represents a bond.

In at least one group selected from the group consisting of an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, and a group having a sulfoneimide structure, sulfoneimide The sulfone imide structure in the group having a structure represents the following structure. In the following structure, * represents a bond.

 

 

The organic borate anion having a ring structure is more preferably an organic borate anion represented by the following formula (III).

In formula (III), R ₇ to R ₁₄ may be the same or different and each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, an arylcarbonyl group, an alkyl ester group, or an alkenyl group. Represents an ester group. Adjacent two of R ₇ to R ₁₄ may be bonded to each other to form a ring structure.

The alkyl group, the alkenyl group and the aryl group in each group of R ₇ to R ₁₄ in the formula (III) are the same as the alkyl group, the alkenyl group and the aryl group in R ₁ to R ₄ in the above formula (I). It can be used.

The alkyl ester group includes an alkylcarbonyloxy group and an alkyloxycarbonyl group, and the alkenyl ester group includes an alkenylcarbonyloxy group and an alkenyloxycarbonyl group.

In formula (III),
R ₇ to R _{10 each} represent an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, or a group having a sulfoneimide structure (specific examples are as described above Is not preferred),
Each of R ₁₁ to R ₁₄ is an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, or a group having a sulfoneimide structure (specific examples are as described above Is not preferred.

[Counter cation]
The counter cation which comprises the specific compound which concerns on this invention should just be a cation which can form a salt compound by the said organic borate anion and ionic bond.
The counter cation may be an inorganic cation or an organic cation. Examples of the inorganic cation include alkali metal ions such as lithium ion, sodium ion and potassium ion, and alkaline earth metal ions such as calcium, magnesium ion and calcium ion.
Organic cations include organic cations in which a positive charge is present on the nitrogen atom. The organic cation having a positive charge on the nitrogen atom is represented by the formula: N ⁺ (R ⁰¹ ) (R ⁰² ) (R ⁰³ ) (R ⁰⁴ ) (where R ⁰¹ , R ⁰² , R ⁰³ , R ⁰⁴ is And each independently represents an ammonium cation represented by an alkyl group or an aryl group, a pyridinium cation, an imidazolium cation and the like.
Examples of ammonium cations include tetramethyl ammonium, tetraethyl ammonium, tetrabutyl ammonium and the like.

The counter cation is preferably a diaryl iodonium cation or a triaryl sulfonium cation. Certain compounds having a diaryliodonium cation or triarylsulfonium cation as a counter cation are very useful as a polymerization initiator. Moreover, this specific compound also functions well as an acid generator, as described later.

The diaryl iodonium cation and the triaryl sulfonium cation respectively include, for example, an iodonium cation represented by the following formula (C1) and a sulfonium cation represented by (C2).

In formulas (C1) and (C2), Ar1, Ar2, Ar3, Ar4 and Ar5 each independently represent a group represented by formula (C3). In formula (C3), R ²⁰ represents an alkyl group, an alkoxy group or a halogen atom, and a plurality of R ²⁰ may be the same or different. l represents an integer of 0 to 5;

Specific examples of the diaryliodonium cation include diphenyliodonium cation, 4-methoxyphenyl-4- (2-methylpropyl) phenyliodonium cation, 4-chlorophenyl-4-phenyliodonium cation, 4- (2-methylpropyl) phenyl- p-Tolyliodonium cation, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium cation, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium cation, 4-octyloxyphenyl-2,4, Examples include 6-trimethoxyphenyliodonium cation and bis (4-tert-butylphenyl) iodonium cation.

Specific examples of triarylsulfonium cation include triphenylsulfonium cation, bis (4-chlorophenyl) phenylsulfonium cation, bis (4-chlorophenyl) -4-methylphenylsulfonium cation, tris (4-chlorophenyl) sulfonium cation, tris ( Examples include 2,4-dichlorophenyl) sulfonium cation, bis (2,4-dichlorophenyl) phenylsulfonium cation, and bis (2,4-dichlorophenyl) -4-methoxyphenylsulfonium cation.

Specific examples of the specific compound according to the present invention are shown below, but the present invention is not limited thereto. In specific examples of specific compounds below, an organic borate anion (anion part) and a counter cation (cation part) are separately described. For example, the specific compound I-1 is a tetraphenoxy borate as an organic borate anion It is meant to be composed of an anion and 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium cation as a counter cation. The same applies to the other specific compounds I-2 to I-40. Ts represents a tosyl group, and Me represents a methyl group.

The specific compounds according to the present invention may be used alone or in combination of two or more.
In the composition of the present invention, the content of the specific compound largely varies depending on the structure of the specific compound, the intended effect, the use and the like. Generally, the total solid content of the composition is preferably 0.1 to 50% by mass, more preferably 0.5 to 40% by mass, and still more preferably 1 to 30% by mass. As used herein, total solids content refers to the total amount of components excluding volatile components such as solvents in the composition of the present invention.

The specific compound according to the present invention exhibits various effects. The composition of the present invention containing the specific compound has high heat aging stability. This is considered to be due to the excellent properties of the organic borate anion constituting the specific compound, and even when compared with the borate anion described in Patent Document 1, a remarkable improvement effect on the thermal temporal stability is recognized. Therefore, the lithographic printing plate precursor to which the composition of the present invention is applied also has excellent heat aging stability.
Further, the composition of the present invention containing the specific compound is excellent in the electron transfer efficiency or the light-to-heat conversion efficiency from the infrared absorbing agent resulting from the infrared exposure to the specific compound. For this reason, curing reaction such as polymerization or heat fusion of the polymerizable compound is promoted, and it is considered that good curability is exhibited. Thus, for example, a lithographic printing plate produced from a lithographic printing plate precursor to which the composition of the present invention is applied has excellent press life.
Furthermore, the organic borate anion constituting the specific compound has a water affinity structure consisting of an oxygen atom or the like in contact with a boron atom, and a comparison of such a relatively hydrophilic portion with an aromatic ring present therearound It is considered to have surfactant activity because it consists of a hydrophobic moiety. Therefore, for example, the lithographic printing plate precursor to which the composition of the present invention is applied exhibits good on-press developability as compared with the lithographic printing plate precursor to which the borate anion described in Patent Document 1 is applied.
Furthermore, since the organic borate anion constituting the specific compound functions as an acid, a colored image can be formed by using an acid color former such as a leuco dye in combination with the composition of the present invention as described later. . The organic borate anion which comprises a specific compound is excellent in color development performance, therefore, for example, a lithographic printing plate precursor to which the composition of the present invention is applied exhibits excellent plate-making ability.
Furthermore, a lithographic printing plate precursor wherein a polymerization initiator containing PF ₆ ⁻ known as an inorganic anion is used in combination with an acid color former such as a leuco dye has a problem that ring-like coloring occurs with heat aging. The ring-like color development is a phenomenon in which fine ring-like color formation occurs over the entire surface of the lithographic printing plate precursor, which hinders the plate-making operation. PF ₆ ^- in place of, the lithographic printing plate precursor of the polymerization initiator in combination with an acid color former such as a leuco dye containing an organic borate anion of the present invention has the advantage that a thermal aging does not cause ring coloring.

Furthermore, the counter cation may be a counter cation in the cyanine dye. The counter cation in the cyanine dye will be described in the following description of the infrared absorber.

The composition of the present invention is preferably a composition of the following forms (1) to (3).
The composition of the form (1) contains one or more of a specific compound, an infrared absorber, a binder polymer and polymer particles, and a polymerizable compound.
The composition of the form (2) contains one or more of a specific compound, an acid color former, an infrared absorber, a binder polymer and polymer particles, and a polymerizable compound.
The composition of the form (3) contains one or more of a specific compound, an acid color former, an infrared absorber, a binder polymer and polymer particles, a polymerizable compound, and a polymerization initiator.
The specific compound in the composition of form (1) is preferably a polymerization initiator whose counter cation is a diaryliodonium cation or a triarylsulfonium cation.
The specific compound in the composition of the form (2) is preferably a polymerization initiator whose counter cation is a diaryliodonium cation or a triarylsulfonium cation.
The specific compound in the composition of the form (3) is preferably an additive in which the counter cation is an alkali metal ion, an alkaline earth metal ion or an organic cation having a charge on a nitrogen atom.

Below, it describes about the component contained in the composition of this invention.

[Infrared absorber]
The composition of the present invention preferably contains an infrared absorber. The infrared absorber has a function of being excited by infrared rays to perform electron transfer and / or energy transfer to a polymerization initiator or the like. It also has the function of converting the absorbed infrared radiation into heat. The infrared absorber preferably has maximum absorption in the wavelength range of 750 to 1,400 nm. As an infrared absorber, a dye or a pigment is mentioned, and a dye is preferably used.

As the dyes, commercially available dyes and known dyes described in the literature such as "Dye Handbook" (edited by the Society of Synthetic Organic Chemistry, published in 1945) can be used. Specifically, dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Can be mentioned.
Among the dyes, cyanine dyes, squarylium dyes and pyrylium salts are preferable, cyanine dyes are more preferable, and indolenine cyanine dyes are particularly preferable.

Examples of the cyanine dye include cyanine dyes represented by the following general formula (a).

In the general formula (a), X ¹ represents a hydrogen atom, a halogen atom, -N (R ⁹ ) (R ¹⁰ ), -X ² -L ¹ or a group shown below. Here, R ⁹ and R ^{10, which} may be the same or different, each independently represent an aromatic hydrocarbon group having 6 to 10 carbon atoms, an alkyl group having 1 to 8 carbon atoms, or a hydrogen atom, or ⁹ and R ¹⁰ may bond to each other to form a ring. The aromatic hydrocarbon group having 6 to 10 carbon atoms or the alkyl group having 1 to 8 carbon atoms may have a substituent. Both R ⁹ and R ¹⁰ are preferably phenyl. X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 12 carbon atoms containing a hetero atom. Here, the hetero atom represents N, S, O, a halogen atom, or Se. In the groups shown below, Xa ⁻ has the same meaning as Za ⁻ described later, and Ra represents a hydrogen atom, or a substituent selected from an alkyl group, an aryl group, a substituted or unsubstituted amino group and a halogen atom.

In the general formula (a), R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the viewpoint of storage stability of the coating solution for image recording layer, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and further, R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferred to form a 6-membered ring.

In the general formula (a), Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group. The aromatic hydrocarbon group may have a substituent. Preferred aromatic hydrocarbon groups include benzene ring group and naphthalene ring group. 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, which} may be the same or different, each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ^{4, which} may be the same or different, each represent a hydrocarbon group having 20 or less carbon atoms. The hydrocarbon group having 20 or less carbon atoms may have a substituent. As a preferable substituent, a C12 or less alkoxy group, a carboxy group, and a sulfo group are mentioned. R ⁵ , R ⁶ , R ⁷ and R ^{8, which} may be the same or different, each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. It is preferably a hydrogen atom in view of the availability of the raw material. Furthermore, Za ^- represents a counter anion. However, when the cyanine dye represented by the general formula (a) has an anionic substituent in its structure and charge neutralization is not required, Za ^- is not necessary. From the viewpoint of storage stability of the coating solution for image recording layer, Za ^- is preferably a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, a sulfonate ion or the above organic borate anion, and a perchlorate ion The hexafluorophosphate ion, the aryl sulfonate ion, or the organic borate anion is more preferable.

In the cyanine dye represented by formula (a), X ¹ is more preferably a diphenylamino group. More preferably, X ¹ is a diphenylamino group, and both Y ¹ and Y ² are dimethylmethylene groups.

When the cyanine dye contains the above organic borate anion as a counter ion (for example, Za ⁻ in the general formula (a)), the cyanine dye corresponds to the specific compound according to the present invention. The cyanine dye which contains the said organic borate anion as a counter ion is excellent in solubility.

Specific examples of the cyanine dye include compounds described in paragraphs 0017 to 0019 of JP-A 2001-133969, paragraphs 0016 to 0021 of JP-A 2002-023360, and paragraphs 0012 to 0037 of JP-A 2002-040638. Compounds described in JP-A-2002-278057, preferably compounds described in paragraphs 0034-0041 of JP-A-2002-195018, and particularly preferably compounds described in JP-A-2007-90850 The compounds described in 0043 can be mentioned.
Further, compounds described in paragraphs 0008 to 0009 of JP-A-5-5005 and paragraphs 0022 to 0025 of JP-A 2001-222101 can also be preferably used.
As the pigment, the compounds described in paragraphs 0072 to 0076 of JP-A-2008-195018 are preferable.

The infrared absorbers may be used alone or in combination of two or more.
The infrared absorbing agent can be contained in any amount in the composition. The content of the infrared absorber is preferably 0.05 to 30% by mass, more preferably 0.1 to 20% by mass, and still more preferably 0.2 to 10% by mass, in the total solid content of the composition.

[Polymerizable compound]
The composition of the present invention preferably contains a polymerizable compound. The polymerizable compound may be, for example, a radically polymerizable compound or a cationically polymerizable compound, but it is an addition polymerizable compound (ethylenically unsaturated compound) having at least one ethylenically unsaturated bond. Is preferred. As the ethylenically unsaturated compound, a compound having at least one terminal ethylenic unsaturated bond is preferable, and a compound having two or more terminal ethylenic unsaturated bonds is more preferable. The polymerizable compound can have a chemical form such as, for example, a monomer, a prepolymer, that is, a dimer, a trimer or an oligomer, or a mixture thereof.

Examples of the monomer include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid), esters thereof and amides thereof. Preferably, esters of unsaturated carboxylic acid and polyhydric alcohol compound, and amides of unsaturated carboxylic acid and polyhydric amine compound are used. Also, addition reaction products of unsaturated carboxylic acid esters or amides having a nucleophilic substituent such as hydroxy group, amino group and mercapto group with monofunctional or polyfunctional isocyanates or epoxies, and monofunctional or monofunctional Dehydration condensation products with polyfunctional carboxylic acids and the like are also suitably used. In addition, unsaturated carboxylic acid esters having an electrophilic substituent such as an isocyanate group and an epoxy group, or an addition reaction product of an amide with a monofunctional or polyfunctional alcohol, an amine or a thiol, and a halogen atom, Also suitable are substitution products of unsaturated carboxylic acid esters or amides having a leaving substituent such as tosyloxy group, and amides with monofunctional or polyfunctional alcohols, amines, and thiols. As another example, a compound group in which the above-mentioned unsaturated carboxylic acid is replaced by unsaturated phosphonic acid, styrene, vinyl ether and the like can also be used. These compounds are disclosed in JP-A-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296 and JP-A-9-179297. Patent Publication Nos. 9-179298, 2004-294935, 2006-243493, 2002-275129, 2003-64130, 2003-280187, It is described in Japanese Patent Application Laid-Open No. 10-333321 and the like.

Specific examples of monomers of esters of polyhydric alcohol compounds and unsaturated carboxylic acids include, as acrylic acid esters, ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, and the like. Examples thereof include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, ethylene oxide (EO) modified triacrylate isocyanurate, and polyester acrylate oligomer. As methacrylic acid ester, tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl] Dimethylmethane, bis [p- (methacryloxyethoxy) phenyl] dimethylmethane and the like can be mentioned. Further, specific examples of monomers of amides of a polyvalent amine compound and an unsaturated carboxylic acid include methylenebisacrylamide, methylenebismethacrylamide, 1,6-hexamethylenebisacrylamide, 1,6-hexamethylenebismethacrylamide, Diethylene triamine tris acrylamide, xylylene bis acrylamide, xylylene bis methacrylamide etc. are mentioned.

Further, urethane addition polymerization compounds produced by using an addition reaction of an isocyanate and a hydroxy group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. Vinyl containing two or more polymerizable vinyl groups in one molecule obtained by adding a hydroxyl group-containing vinyl monomer represented by the following formula (M) to a polyisocyanate compound having two or more isocyanate groups Urethane compounds and the like can be mentioned.
CH ₂ = C (R ^M4 ) COOCH ₂ CH (R ^M5 ) OH (M)
In formula (M), R ^M4 and R ^M5 each independently represent a hydrogen atom or a methyl group.

Also, urethane acrylates described in JP-A-51-37193, JP-B-2-32293, JP-B 2-16765, JP-A 2003-344997, JP-A 2006-65210, The ethylenes described in JP-B-58-49860, JP-B-56-17654, JP-B-62-39417, JP-B-62-39418, JP-A-2000-250211 and JP-A-2007-94138. Urethane Compounds Having an Oxide-Based Skeleton, U.S. Pat. Nos. 7,153,632, JP-A-8-505,598, JP-A-2007-293221, JP-A-2007-293223, and Urethane Compounds Having a Hydrophilic Group Are also suitable.

The details of the method of use, such as the structure of the polymerizable compound, single use or combined use, and the addition amount can be arbitrarily set in consideration of the final use of the composition and the like.
The content of the polymerizable compound is preferably 5 to 75% by mass, more preferably 10 to 70% by mass, and still more preferably 15 to 60% by mass, based on the total solid content of the composition.

[Polymerization initiator]
The composition of the present invention preferably contains a polymerization initiator. The polymerization initiator is a compound that generates polymerization initiation species such as radicals and cations by light and / or heat energy, and known thermal polymerization initiators, compounds having a small bond dissociation energy, and photopolymerization initiators And so on.
As a polymerization initiator, an infrared photosensitive polymerization initiator is preferable. Moreover, as a polymerization initiator, a radical polymerization initiator is preferable.
Examples of the radical polymerization initiator include organic halides, carbonyl compounds, azo compounds, organic peroxides, metallocene compounds, azide compounds, hexaarylbiimidazole compounds, disulfone compounds, oxime ester compounds, and onium salt compounds. Be

As the organic halide, for example, compounds described in paragraphs 0022 to 0023 of JP-A-2008-195018 are preferable.
As the carbonyl compound, for example, compounds described in paragraph 0024 of JP-A-2008-195018 are preferable.
Examples of the azo compound include azo compounds described in JP-A-8-108621.
As the organic peroxide, for example, compounds described in paragraph 0025 of JP-A-2008-195018 are preferable.
As the metallocene compound, for example, the compounds described in paragraph 0026 of JP-A-2008-195018 are preferable.
Examples of the azide compound include compounds such as 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.
As the hexaarylbiimidazole compound, for example, compounds described in paragraph 0027 of JP-A-2008-195018 are preferable.
Examples of the disulfone compound include compounds described in JP-A-61-166544 and JP-A-2002-328465.
As the oxime ester compound, for example, compounds described in paragraphs 0028 to 0030 of JP-A-2008-195018 are preferable.

Among the polymerization initiators, oxime esters and onium salts are more preferable from the viewpoint of curability, and onium salts such as iodonium salts, sulfonium salts and azinium salts are further preferable. When the composition of the present invention is applied to a lithographic printing plate precursor, iodonium salts and sulfonium salts are particularly preferred. Specific examples of iodonium salts and sulfonium salts are shown below, but the present invention is not limited thereto.

As an example of the iodonium salt, diphenyliodonium salt is preferable, and in particular, diphenyliodonium salt having an electron donating group as a substituent, for example, diphenyliodonium salt substituted with an alkyl group or an alkoxyl group is preferable, and asymmetric diphenyliodonium salt is also preferable. preferable. Specific examples thereof include diphenyliodonium = hexafluorophosphate, 4-methoxyphenyl-4- (2-methylpropyl) phenyliodonium = hexafluorophosphate, 4- (2-methylpropyl) phenyl-p-tolyliodonium = hexa Fluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium = tetrafluoroborate, 4-octyloxy Phenyl-2,4,6-trimethoxyphenyliodonium = 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, bis ( -t- butylphenyl) iodonium hexafluorophosphate and the like.

Examples of sulfonium salts are preferably triarylsulfonium salts, particularly preferably triarylsulfonium salts having an electron withdrawing group as a substituent, for example, a triarylsulfonium salt in which at least a part of the group on the aromatic ring is substituted with a halogen atom. And triarylsulfonium salts in which the total substitution number of halogen atoms on the aromatic ring is 4 or more are more preferable. Specific examples thereof include triphenylsulfonium = hexafluorophosphate, triphenylsulfonium = benzoyl formate, bis (4-chlorophenyl) phenylsulfonium = benzoyl formate, bis (4-chlorophenyl) -4-methylphenylsulfonium = tetrafluoro Borate, tris (4-chlorophenyl) sulfonium = 3,5-bis (methoxycarbonyl) benzenesulfonate, tris (4-chlorophenyl) sulfonium = hexafluorophosphate, tris (2,4-dichlorophenyl) sulfonium = hexafluorophos Fert is mentioned.

The polymerization initiator can contain the organic borate anion according to the present invention as an anion. In this case, the polymerization initiator corresponds to the specific compound according to the present invention.

The polymerization initiator may be used alone or in combination of two or more.
The content of the polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and still more preferably 0.8 to 20% by mass, based on the total solid content of the composition.

[Binder polymer]
The composition of the present invention preferably contains a binder polymer. As the binder polymer, polymers having film properties are preferable, and known binder polymers used in the composition can be suitably used. Among them, as the binder polymer, (meth) acrylic resin, polyvinyl acetal resin and polyurethane resin are preferable.

When the composition of the present invention is applied to the image recording layer of a lithographic printing plate precursor, a known binder polymer used in the image recording layer of the lithographic printing plate precursor can be suitably used as the binder polymer. As an example, a binder polymer (hereinafter, also referred to as a binder polymer for on-press development) used for an on-press development type lithographic printing plate precursor will be described in detail.
As a binder polymer for on-press development, a binder polymer having an alkylene oxide chain is preferable. The binder polymer having an alkylene oxide chain may have a poly (alkylene oxide) moiety in the main chain or in the side chain. Further, it may be a graft polymer having a poly (alkylene oxide) in a side chain, or a block copolymer of a block constituted by a poly (alkylene oxide) -containing repeating unit and a block constituted by a (alkylene oxide) non-containing repeating unit.
When it has a poly (alkylene oxide) site in the main chain, a polyurethane resin is preferred. The polymer of the main chain when having a poly (alkylene oxide) moiety in the side chain includes (meth) acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, polystyrene resin, novolac type Phenol resin, polyester resin, synthetic rubber, natural rubber are mentioned, and (meth) acrylic resin is particularly preferable.

As the alkylene oxide, an alkylene oxide having 2 to 6 carbon atoms is preferable, and ethylene oxide or propylene oxide is particularly preferable.
The number of repeating alkylene oxides in the poly (alkylene oxide) moiety is preferably 2 to 120, more preferably 2 to 70, and still more preferably 2 to 50.
If the number of repetitions of the alkylene oxide is 120 or less, both of the printing durability due to abrasion and the printing durability due to ink receptivity do not deteriorate, which is preferable.

The poly (alkylene oxide) moiety is preferably contained as a side chain of the binder polymer in a structure represented by the following formula (AO), and as a side chain of a (meth) acrylic resin, it is represented by the following formula (AO) More preferably, it is contained in the following structure.

In formula (AO), y represents 2 to 120, R ₁ represents a hydrogen atom or an alkyl group, and R ₂ represents a hydrogen atom or a monovalent organic group.
As the monovalent organic group, an alkyl group having 1 to 6 carbon atoms is preferable. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, n- And hexyl, isohexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, cyclopentyl and cyclohexyl groups.
In the formula (AO), y is preferably 2 to 70, and more preferably 2 to 50. R ₁ is preferably a hydrogen atom or a methyl group, particularly preferably a hydrogen atom. R ₂ is particularly preferably a hydrogen atom or a methyl group.

The binder polymer may have crosslinkability in order to improve the film strength of the image area. In order to give the polymer crosslinkability, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.
Examples of polymers having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene, poly-1,4-isoprene and the like.
An example of a polymer having an ethylenically unsaturated bond in the side chain of the molecule is a polymer of an ester or amide of acrylic acid or methacrylic acid, and the residue of ester or amide (R of -COOR or -CONHR) is Mention may be made of polymers having ethylenically unsaturated bonds.

As an example of the residue having the ethylenically unsaturated bond (the above R),-(CH ₂ ) _n CR ^1A = CR ^{2 AR} 3 ^-A ,-(CH ₂ O) _n CH ₂ CR ^{1 A} = CR ² AR ^{3 A} ,- _{(CH 2 CH 2 O) n} CH 2 CR 1A = CR 2A R 3A, - (CH 2) n NH-CO-O-CH 2 CR 1A = CR 2A R 3A, - (CH 2) n -O-CO -CR ^1A = CR ^2A R ^3A and-(CH ₂ CH ₂ O) ₂ -X ^A (wherein, R ^A1 to R ^A3 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, And R ^A1 and R ^A2 or R ^A3 may combine with each other to form a ring, n represents an integer of 1 to 10. X ^A represents a di-aryl group, an alkoxy group or an aryloxy group. Represents a cyclopentadienyl residue. It can be mentioned.

Specific examples of the ester residue include —CH ₂ CH = CH ₂ , —CH ₂ CH ₂ O—CH ₂ CH = CH ₂ , —CH ₂ C (CH ₃ ) = CH ₂ and —CH ₂ CH = CH— C ₆ H ₅ , —CH ₂ CH ₂ OCOCH = CH—C ₆ H ₅ , —CH ₂ CH ₂ —NHCOO—CH ₂ CH = CH ₂ and —CH ₂ CH ₂ O—X, wherein X is a dicyclo And a pentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH = CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue) and —CH ₂ CH ₂ —OCO—CH = CH ₂ Can be mentioned.

In the binder polymer having crosslinkability, for example, free radicals (polymerization initiating radicals or propagating radicals in the polymerization process of the polymerizable compound) are added to the crosslinkable functional group to directly or interpolymerize the polymerization chain of the polymerizable compound. Addition polymerization is performed to form crosslinks between polymer molecules and cure. Alternatively, an atom in the polymer (for example, a hydrogen atom on a carbon atom adjacent to a functional crosslinking group) is extracted by a free radical to generate a polymer radical, which combines with one another to form a crosslink between polymer molecules It forms and cures.

The content of the crosslinkable group in the binder polymer (content of the radically polymerizable unsaturated double bond by iodine titration) is preferably 0.1 per gram of the binder polymer from the viewpoint of good sensitivity and good storage stability. It is preferably -10.0 mmol, more preferably 1.0-7.0 mmol, still more preferably 2.0-5.5 mmol.

Specific examples 1 to 11 of the binder polymer are shown below, but the present invention is not limited thereto. In the following exemplified compounds, the numerical values shown in parallel with each repeating unit (the numerical values shown in parallel with the main chain repeating unit) represent the mole percentage of the repeating unit. The numerical value added to the repeating unit of the side chain indicates the number of repeats of the repeating site. Also, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

The molecular weight of the binder polymer is 2,000 or more, preferably 5,000 or more, and more preferably 10,000 to 300,000, as weight average molecular weight (Mw) as polystyrene conversion value by GPC method.
Further, in the present invention, the oligomer has a Mw of 800 or more and less than 2,000, and the polymer has a Mw of 2,000 or more.

If necessary, hydrophilic polymers such as polyacrylic acid and polyvinyl alcohol described in JP-A-2008-195018 can be used in combination. Also, lipophilic polymers and hydrophilic polymers can be used in combination.

When the composition of the present invention is applied to the image recording layer of a lithographic printing plate precursor, the binder polymer may be present in the composition as a polymer functioning as a binder for each component, or in the form of particles. You may When present in the form of particles, the volume average primary particle size is preferably 10 to 1,000 nm, more preferably 20 to 300 nm, and still more preferably 30 to 120 nm.
In the present invention, the volume average primary particle size can be obtained by taking an electron micrograph of the particle, measuring the total particle size of 5000 particles on the photograph, and calculating the arithmetic mean value.
For non-spherical particles, the particle diameter value of spherical particles having the same particle area as the particle area on the photograph is measured as the particle diameter (equivalent circle diameter).
The method of measuring the volume average primary particle size is the same as for the particles other than the binder polymer present in the form of particles, unless otherwise specified.

The binder polymer may be used alone or in combination of two or more.
The binder polymer can be contained in any amount in the composition. The content of the binder polymer can be appropriately selected depending on the application of the composition of the present invention and the like, but it is preferably 1 to 90% by mass, more preferably 5 to 80% by mass in the total solid content of the composition.

[Acid color developing agent]
The composition of the present invention can contain an acid color former. The acid color former is a compound having a property of developing a color by accepting an electron accepting compound (for example, a proton such as an acid). As an acid color developing agent, a colorless compound which has a partial skeleton such as lactone, lactam, sultone, spiropyran, ester or amide, and which partially opens or cleaves the partial skeleton when contacted with an electron accepting compound preferable.

Examples of such acid-coloring agents include: 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide (referred to as "crystal violet lactone"), 3,3-bis (4- Dimethylaminophenyl) phthalide, 3- (4-dimethylaminophenyl) -3- (4-diethylamino-2-methylphenyl) -6-dimethylaminophthalide, 3- (4-dimethylaminophenyl) -3- (1 , 2-Dimethylindol-3-yl) phthalide, 3- (4-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindole-3) -Yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-biphenyl (9-Ethylcarbazol-3-yl) -6-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -6-dimethylaminophthalide, 3- (4-dimethylaminophenyl) -3- (1-methylpyrrol-3-yl) -6-dimethylaminophthalide,

3,3-bis [1,1-bis (4-dimethylaminophenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1,1-bis ( 4-Pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide, 3,3-bis [1- (4-dimethylaminophenyl) -1- (4-methoxyphenyl) Ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1- (4-pyrrolidinophenyl) -1- (4-methoxyphenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3- [1,1-di (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- (4-diethylaminophenyl) ) Phthalide, 3- [1,1-di (1-ethyl-2-methyl) Leindol-3-yl) ethylene-2-yl] -3- (4-N-ethyl-N-phenylaminophenyl) phthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-n) -Octyl-2-methylindol-3-yl) -phthalide, 3,3-bis (1-n-octyl-2-methylindol-3-yl) -phthalide, 3- (2-methyl-4-diethylaminophenyl) Phthalides such as 3- (1-n-octyl-2-methylindol-3-yl) -phthalide;

4,4-Bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl-leucoauramine, N-2,4,5-trichlorophenyl leucoauramine, rhodamine-B-anilinolactam, rhodamine- (4-nitroanilino ) Lactam, rhodamine-B- (4-chloroanilino) lactam, 3,7-bis (diethylamino) -10-benzoylphenoxazine, benzoyl leuco methylene blue, 4-nitrobenzoyl methylene blue,

3,6-Dimethoxyfluoran, 3-dimethylamino-7-methoxyfluoran, 3-diethylamino-6-methoxyfluoran, 3-diethylamino-7-methoxyfluoran, 3-diethylamino-7-chlorofluoran, 3 -Diethylamino-6-methyl-7-chlorofluoran, 3-diethylamino-6,7-dimethylfluoran, 3-N-cyclohexyl-N-n-butylamino-7-methylfluoran, 3-diethylamino-7- Dibenzylaminofluoran, 3-diethylamino-7-octylaminofluoran, 3-diethylamino-7-di-n-hexylaminofluoran, 3-diethylamino-7-anilinofluoran, 3-diethylamino-7- ( 2'-Fluorophenylamino) fluorane, 3-diethylamino 7- (2'-chlorophenylamino) fluoran, 3-diethylamino-7- (3'-chlorophenylamino) fluoran, 3-diethylamino-7- (2 ', 3'-dichlorophenylamino) fluoran, 3-diethylamino-7- (3′-trifluoromethylphenylamino) fluoran, 3-di-n-butylamino-7- (2′-fluorophenylamino) fluoran, 3-di-n-butylamino-7- (2′-chlorophenylamino ) Fluoran, 3-N-isopentyl-N-ethylamino-7- (2'-chlorophenylamino) fluoran,

3-N-n-Hexyl-N-ethylamino-7- (2'-chlorophenylamino) fluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-di-n-butylamino-6- Chloro-7-anilinofluorane, 3-diethylamino-6-methoxy-7-anilinofluorane, 3-di-n-butylamino-6-ethoxy-7-anilinofluorane, 3-pyrrolidino-6- 6 Methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-morpholino-6-methyl-7-anilinofluorane, 3-dimethylamino-6-methyl-7- Anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-di-n-butylamino-6-methyl-7-anilinofluorane, 3-di- -Pentylamino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-methylamino-6-methyl-7-anilinofluorane, 3-Nn-propyl-N-methylamino-6- Methyl-7-anilinofluorane, 3-N-n-propyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-n-butyl-N-methylamino-6-methyl- 7-anilinofluorane, 3-N-n-butyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-isobutyl-N-methylamino-6-methyl-7-anilino Fluoran, 3-N-Isobutyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-isopentyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N -N-hexi -N-Methylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-N-ethylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-N-n-propyl Amino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-Nn-butylamino-6-methyl-7-anilinofluorane, 3-N-cyclohexyl-Nn-hexylamino- 6-Methyl-7-anilinofluorane, 3-N-cyclohexyl-Nn-octylamino-6-methyl-7-anilinofluorane,

3-N- (2'-Methoxyethyl) -N-methylamino-6-methyl-7-anilinofluorane, 3-N- (2'-methoxyethyl) -N-ethylamino-6-methyl-7 -Anilinofluorane, 3-N- (2'-methoxyethyl) -N-isobutylamino-6-methyl-7-anilinofluorane, 3-N- (2'-ethoxyethyl) -N-methylamino -6-Methyl-7-anilinofluorane, 3-N- (2'-ethoxyethyl) -N-ethylamino-6-methyl-7-anilinofluorane, 3-N- (3'-methoxypropyl) ) -N-Methylamino-6-methyl-7-anilinofluorane, 3-N- (3'-methoxypropyl) -N-ethylamino-6-methyl-7-anilinofluorane, 3-N- (3'-Ethoxypropyl) -N- Tylamino-6-methyl-7-anilinofluorane, 3-N- (3'-ethoxypropyl) -N-ethylamino-6-methyl-7-anilinofluorane, 3-N- (2'-tetrahydrofuran Furfuryl) -N-ethylamino-6-methyl-7-anilinofluorane, 3-N- (4'-methylphenyl) -N-ethylamino-6-methyl-7-anilinofluorane, 3- Diethylamino-6-ethyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (3'-methylphenylamino) fluoran, 3-diethylamino-6-methyl-7- (2 ', 6'-) Dimethylphenylamino) fluoran, 3-di-n-butylamino-6-methyl-7- (2 ′, 6′-dimethylphenylamino) fluoran, 3-di-n-butylamino-7- 2 ′, 6′-Dimethylphenylamino) fluoran, 2,2-bis [4 ′-(3-N-cyclohexyl-N-methylamino-6-methylfluoran) -7-ylaminophenyl] propane, 3- [4 ′-(4-phenylaminophenyl) aminophenyl] amino-6-methyl-7-chlorofluorane, 3- [4 ′-(dimethylaminophenyl)] amino-5,7-dimethylfluoran, and the like fluorans Kind,

3- (2-Methyl-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-n-propoxycarbonylamino-4-di-n -Propylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-methylamino-4-di-n-propylaminophenyl) -3- (1 -Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-methyl-4-din-hexylaminophenyl) -3- (1-n-octyl-2-methylindole-3-) Yl) -4,7-diazaphthalide, 3,3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3,3-bis (1-n-octyl-2-methylindole 3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-) 4-diethylaminophenyl) -3- (1-octyl-2-methylindol-3-yl) -4 or 7-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2) -Methylindol-3-yl) -4 or 7-azaphthalide, 3- (2-hexyloxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4 or 7- Azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-phenylindol-3-yl) -4 or 7-azaphthalide, -(2-butoxy-4-diethylaminophenyl) -3- (1-ethyl-2-phenylindol-3-yl) -4 or 7-azaphthalide 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphtho- (3-methoxybenzo) spiropyran, 3-propyl-spiro-dibenzopyran-3,6-bis (dimethylamino) fluorene- Phthalides such as 9-spiro-3 ′-(6′-dimethylamino) phthalide, 3,6-bis (diethylamino) fluoren-9-spiro-3 ′-(6′-dimethylamino) phthalide,

Furthermore, 2'-anilino-6 '-(N-ethyl-N-isopentyl) amino-3'-methylspiro [isobenzofuran-1 (3H), 9'-(9H) xanthen-3-one, 2'-anilino -6 '-(N-ethyl-N- (4-methylphenyl)) amino-3'-methylspiro [isobenzofuran-1 (3H), 9'-(9H) xanthene] -3-one, 3'-N , N-Dibenzylamino-6'-N, N-diethylamino spiro [isobenzofuran-1 (3H), 9 '-(9H) xanthene] -3-one, 2'-(N-methyl-N-phenyl) Amino-6 ′-(N-ethyl-N- (4-methylphenyl)) aminospiro [isobenzofuran-1 (3H), 9 ′-(9H) xanthene] -3-one and the like.

The acid color former is preferably at least one compound selected from the group consisting of spiropyran compounds, spirooxazine compounds, spirolactone compounds and spirolactam compounds.
The hue of the dye after color development is preferably green, blue or black from the viewpoint of visibility.

It is also possible to use a commercial item as the acid color former. For example, ETAC, RED 500, RED 520, CVL, S-205, BLACK 305, BLACK 400, BLACK 100, BLACK 500, H-7001, GREEN 300, NIRBLACK 78, BLUE 220, H-3035, BLUE 203, ATP, H-1046, H-2114 (more, Fukui Yamada Chemical Industry Co., Ltd., ORANGE-DCF, Vermilion-DCF, PINK-DCF, RED-DCF, BLMB, CVL, GREEN-DCF, TH-107 (above, Hodogaya Chemical Co., Ltd.), ODB, ODB-2, ODB-4, ODB-250, ODB-BlackXV, Blue-63, Blue-502, GN-169, GN-2, Green-118, Red-40, Red-8 (above, Yamamoto Kasei ) Co., Ltd.), crystal violet lactone (manufactured by Tokyo Chemicals Industry Co., Ltd.), and the like. Among these commercially available products, ETAC, S-205, BLACK 305, BLACK 400, BLACK 100, BLACK 500, H-7001, GREEN 300, NIRBLACK 78, H-3035, ATP, H-1046, H-2114, GREEN-DCF, Blue-63. GN-169 and crystal violet lactone are preferable because they have good color development characteristics in infrared exposure.

The acid color former may be used alone or in combination of two or more.
The content of the acid color former is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, and still more preferably 2 to 10% by mass in the total solid content of the composition of the present invention.

The acid color former develops color when used in combination with an acid generator. The acid generator is a compound that generates an acid by electron transfer and / or energy transfer from an infrared absorber excited by infrared radiation. The generated acid reacts with the acid color former to form a color. As the acid to be generated, sulfonic acid, hydrochloric acid, hexafluorophosphoric acid, tetrafluoroboric acid and the like are useful.

Examples of the acid generator include onium salts such as iodonium salts, sulfonium salts, phosphonium salts, diazonium salts and azinium salts. Specifically, compounds described in US Pat. No. 4,708,925, JP-A-7-20629, and JP-A-2008-195018 can be mentioned. Also preferred are the benzyl sulfonates described in US Pat. Nos. 5,135,838 and 5,200,544. Furthermore, active sulfonic acid esters described in JP-A-2-100054, JP-A-2-100055 and JP-A-9-197671, and N-hydroxyimide compounds described in JP-A-2008-001740. Also preferred are imido esters such as sulfonic acid esters and disulfone compounds described in JP-A-61-166544, JP-A-2003-328465, and the like. Also, J.J. C. S. Perkin II (1979) 1653-1660), J. Org. C. S. Perkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, JP-A-2000-66385, JP-A-2000-80068, JP-A-2008-195018 Compounds are also preferred. Besides, haloalkyl-substituted s-triazine compounds described in JP-A-7-27129 are also preferable.

As the acid generator, iodonium salts, sulfonium salts and azinium salts are particularly preferred.

For the iodonium salts and sulfonium salts, the descriptions of the iodonium salts and sulfonium salts in the above-mentioned polymerization initiator can be incorporated.

Examples of azinium salts include 1-cyclohexylmethyl oxypyridinium = hexafluorophosphate, 1-cyclohexyloxy-4-phenylpyridinium = hexafluorophosphate, 1-ethoxy-4-phenylpyridinium = hexafluorophosphate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = hexafluorophosphate, 4-chloro-1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-ethoxy-4-cyanopyridinium = hexafluorophosphate, 3,4 -Dichloro-1- (2-ethylhexyloxy) pyridinium = hexafluorophosphate, 1-benzyloxy-4-phenylpyridinium = hexafluorophosphate, 1-phenethyl X-4-phenylpyridinium = hexafluorophosphate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = p-toluenesulfonate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = perfluorobutanesulfonate 1- (2-ethylhexyloxy) -4-phenylpyridinium = bromide and 1- (2-ethylhexyloxy) -4-phenylpyridinium = tetrafluoroborate.

The acid generator can contain the organic borate anion according to the present invention as an anion. In this case, the acid generator corresponds to the specific compound according to the present invention.

The acid generator may be used alone or in combination of two or more.
The content of the acid generator is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and still more preferably 6 to 15% by mass, in the total solid content of the composition of the present invention.

[Radical formation aid]
The composition of the present invention may contain a radical formation coagent. When the composition of the present invention is applied to the image recording layer of a lithographic printing plate precursor, the radical forming aid contributes to the improvement of the printing durability of the lithographic printing plate prepared from the lithographic printing plate precursor. As a radical formation adjuvant, the following five types are mentioned, for example. (I) Alkyl or arylate complex: It is thought that a carbon-hetero bond is oxidatively cleaved to generate an active radical. Specifically, borate compounds and the like can be mentioned. (Ii) Aminoacetic acid compound: It is believed that oxidation breaks up the C—X bond on the carbon adjacent to nitrogen to generate an active radical. As X, a hydrogen atom, a carboxy group, a trimethylsilyl group or a benzyl group is preferable. Specifically, N-phenylglycines (a phenyl group may have a substituent), N-phenyliminodiacetic acid (a phenyl group may have a substituent), etc. are mentioned. Be (Iii) Sulfur-containing compounds: Those in which the nitrogen atom of the above-mentioned aminoacetic acid compound is replaced by a sulfur atom can generate an active radical by the same action. Specific examples thereof include phenylthioacetic acid (which may have a substituent on the phenyl group) and the like. (Iv) Tin-containing compounds: those in which the nitrogen atom of the above-mentioned aminoacetic acid compound is replaced by a tin atom can generate active radicals by the same action. (V) Sulfinates: Oxidation can generate active radicals. Specifically, sodium arylsulfine and the like can be mentioned.

Among the radical formation assistants, borate compounds are preferred. As the borate compound, a tetraaryl borate compound or a monoalkyl triaryl borate compound is preferable, and from the viewpoint of compound stability, a tetraaryl borate compound is more preferable.
As a counter cation which a borate compound has, an alkali metal ion or a tetraalkyl ammonium ion is preferable, and a sodium ion, a potassium ion, or a tetrabutyl ammonium ion is more preferable.

Specific examples of the borate compound include the compounds shown below. Here, X _c ⁺ represents a monovalent cation, and is preferably an alkali metal ion or a tetraalkylammonium ion, and more preferably an alkali metal ion or a tetrabutylammonium ion. In addition, Bu represents an n-butyl group.

The radical generation assistant may be used alone or in combination of two or more.
The content of the radical formation aid is preferably 0.01 to 30% by mass, more preferably 0.05 to 25% by mass, and further preferably 0.1 to 20% by mass, based on the total solid content of the composition of the present invention. preferable.

[Polymer particles]
When the composition of the present invention is applied to the image recording layer of a lithographic printing plate precursor, the composition of the present invention may contain polymer particles from the viewpoint of improving the on-press developability of the lithographic printing plate precursor. The polymer particles are preferably polymer particles that can convert the image recording layer to hydrophobic when heat, preferably heat generated by exposure, is applied.
The polymer particles are at least one selected from heat fusible particles, heat reactive polymer particles, polymer particles having a polymerizable group, microcapsules containing a hydrophobic compound, and microgel (crosslinked polymer particles). Is preferred. Among them, polymer particles and microgels having a polymerizable group are preferable.

As heat fusion particles, for example, Research Disclosure No. 1 in January 1992. No. 33303, thermoplastic polymer particles described in JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, European Patent 931647, etc. are preferred. It can be mentioned.
Specific examples of the polymer constituting the heat fusible particle include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, polyalkylene structure And homopolymers or copolymers of monomers such as acrylates or methacrylates, or mixtures thereof. Preferably, polystyrene, a copolymer containing styrene and acrylonitrile, and polymethyl methacrylate can be mentioned. The number average primary particle size of the heat fusible particles is preferably 0.01 to 2.0 μm.

The thermally reactive polymer particles include polymer particles having a thermally reactive group. The polymer particles having a thermally reactive group form a hydrophobized region by crosslinking due to thermal reaction and functional group change at that time.

The thermally reactive group in the polymer particle having a thermally reactive group may be a functional group which carries out any reaction as long as a chemical bond is formed, and a polymerizable group is preferred. Examples thereof include ethylenically unsaturated groups (for example, acryloyl group, methacryloyl group, vinyl group, allyl group etc.) which undergo radical polymerization reaction, cationically polymerizable groups (for example, vinyl group, vinyloxy group, epoxy group, oxetanyl group) Etc.), isocyanato group to perform addition reaction or a block thereof, epoxy group, vinyloxy group and functional group having active hydrogen atom (such as amino group, hydroxy group, carboxy group etc.) which is a reaction partner thereof, condensation reaction Preferred examples thereof include a carboxy group to be carried out and a hydroxy group or amino group which is a reaction partner, an acid anhydride which performs a ring-opening addition reaction, an amino group or a hydroxy group which is a reaction partner.

Examples of microcapsules include those in which all or part of the components of the image recording layer are encapsulated in microcapsules, as described in JP-A-2001-277740 and JP-A-2001-277742. The components of the image recording layer can also be contained outside the microcapsules. In a preferred embodiment of the image recording layer containing microcapsules, a hydrophobic component is encapsulated in the microcapsule and a hydrophilic component is contained outside the microcapsule.

The microgel (crosslinked polymer particles) can contain part of the components of the composition of the present invention on at least one of its interior and surface. In particular, an embodiment in which a reactive microgel is obtained by having a radically polymerizable group on the surface is preferable from the viewpoint of image formation sensitivity and printing durability.

Known methods can be used to microencapsulate or microgelate the components of the composition of the present invention.
The volume average particle size of the microcapsules or microgels is preferably 0.01 to 3.0 μm, more preferably 0.05 to 2.0 μm, and still more preferably 0.10 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.
The volume average particle size is measured by a light scattering method using a dynamic light scattering type particle size distribution measuring apparatus LB-500 (manufactured by Horiba, Ltd.).
The content of the polymer particles is preferably 5 to 90% by mass in the total solid content of the composition of the present invention.

[Chain transfer agent]
The composition of the present invention may contain a chain transfer agent. The chain transfer agent, when the composition of the present invention is applied to the image recording layer of a lithographic printing plate precursor, contributes to the improvement of the printing durability of a lithographic printing plate prepared from the lithographic printing plate precursor.
The chain transfer agent is preferably a thiol compound, more preferably a thiol having a carbon number of 7 or more from the viewpoint of boiling point (poor volatility), and still more preferably a compound having a mercapto group on an aromatic ring (aromatic thiol compound). The thiol compound is preferably a monofunctional thiol compound.

The following compounds may be mentioned as specific examples of the chain transfer agent.

The chain transfer agent may be used alone or in combination of two or more.
The content of the chain transfer agent is preferably 0.01 to 50% by mass, more preferably 0.05 to 40% by mass, and still more preferably 0.1 to 30% by mass in the total solid content of the composition of the present invention .

[Low molecular weight hydrophilic compound]
When the composition of the present invention is applied to the image recording layer of a lithographic printing plate precursor, the on-press development of the lithographic printing plate precursor without reducing the printing durability of the lithographic printing plate prepared from the lithographic printing plate precursor In order to improve the properties, low molecular weight hydrophilic compounds may be contained. The low molecular weight hydrophilic compound is preferably a compound having a molecular weight of less than 1,000, more preferably a compound having a molecular weight of less than 800, and still more preferably a compound having a molecular weight of less than 500.
As low molecular weight hydrophilic compounds, for example, as water-soluble organic compounds, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, ethers or ester derivatives thereof, glycerin, Polyols such as pentaerythritol, tris (2-hydroxyethyl) isocyanurate, organic amines such as triethanolamine, diethanolamine and monoethanolamine and salts thereof, organic sulfones such as alkyl sulfonic acid, toluene sulfonic acid and benzene sulfonic acid Acids and salts thereof, organic sulfamic acids such as alkyl sulfamic acids and salts thereof, organic sulfuric acids such as alkyl sulfuric acids and alkyl ether sulfuric acids and salts thereof, phenyl phosphonic acid Organic phosphonic acids and salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids, betaines, and the like.

The low molecular weight hydrophilic compound is preferably at least one selected from polyols, organic sulfates, organic sulfonates and betaines.

Specific examples of organic sulfonates include alkyl sulfonates such as sodium n-butyl sulfonate, sodium n-hexyl sulfonate, sodium 2-ethylhexyl sulfonate, sodium cyclohexyl sulfonate, sodium n-octyl sulfonate; , 8,11-Trioxapentadecane-1-sulfonic acid sodium, 5,8,11-trioxaheptadecane-1-sulfonic acid sodium, 13-ethyl-5,8,11-trioxaheptadecane-1-sulfone Alkyl sulfonates containing ethylene oxide chains such as sodium acid sodium and sodium 5,8,11,14-tetraoxatetracosan-1-sulphonate; sodium benzene sulphonate, sodium p-toluene sulphonate, p-hydroxy benzene sulphonic acid The Sodium, sodium p-styrenesulfonate, sodium dimethyl-5-sulfonate isophthalate, sodium 1-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, disodium 1,5-naphthalenedisulfonate, 1,3,6- And arylsulfonic acid salts such as trisodium naphthalene trisulfonate, compounds described in paragraphs 0026 to 0031 of JP 2007-276454 A and paragraphs 0020 to 0047 of JP 2009-154525 A, and the like. The salt may be a potassium salt or a lithium salt.

Organic sulfates include sulfates of alkyl, alkenyl, alkynyl, aryl or heterocyclic monoethers of polyethylene oxide. The number of ethylene oxide units is preferably 1 to 4, and the salt is preferably a sodium salt, potassium salt or lithium salt. Specific examples thereof include the compounds described in paragraphs 0034 to 0038 of JP-A-2007-276454.

Preferred betaines are compounds having 1 to 5 carbon atoms in the hydrocarbon substituent to the nitrogen atom, and specific examples thereof include trimethyl ammonium acetate, dimethyl propyl ammonium acetate, 3-hydroxy-4-trimethyl ammonium Obtilate, 4- (1-pyridinio) butyrate, 1-hydroxyethyl-1-imidazolioacetate, trimethylammonium methanesulfonate, dimethylpropylammonium methanesulfonate, 3-trimethylammonio-1-propanesulfonate, 3 And-(1-pyridinio) -1-propanesulfonate and the like.

The low molecular weight hydrophilic compound has a small hydrophobic part structure and has little surface activity, so that dampening water penetrates the exposed area (image area) of the image recording layer to reduce the hydrophobicity and film strength of the image area. And the ink receptivity and the printing durability of the image recording layer can be well maintained.

The low molecular weight hydrophilic compounds may be used alone or in combination of two or more.
The content of the low molecular weight hydrophilic compound is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, and still more preferably 2 to 10% by mass in the total solid content of the composition of the present invention.

[Sepetic agent]
When the composition of the present invention is applied to the image recording layer of a lithographic printing plate precursor, the ink receptivity of the lithographic printing plate prepared from the lithographic printing plate precursor (hereinafter, also simply referred to as "inking property") In order to improve the viscosity, a sensitizing agent such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer may be contained. In particular, when the lithographic printing plate precursor contains an inorganic stratiform compound in the protective layer, these compounds function as a surface coating agent for the inorganic stratiform compound, and suppress the decrease in the ink resistance during printing by the inorganic stratiform compound. it can.
As a sensitizing agent, it is preferable to use a phosphonium compound, a nitrogen-containing low molecular weight compound, and an ammonium group-containing polymer in combination, and to use a phosphonium compound, a quaternary ammonium salt, and an ammonium group-containing polymer in combination. Is more preferred.

Examples of phosphonium compounds include phosphonium compounds described in JP-A-2006-297907 and JP-A-2007-50660. Specific examples thereof include tetrabutylphosphonium iodide, butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, 1,4-bis (triphenylphosphonio) butane di (hexafluorophosphate), and 1,7-bis (trihydrophosphate). And phenylphosphonio) heptane = sulfate, 1,9-bis (triphenylphosphonio) nonane = naphthalene-2,7-disulfonate and the like.

The nitrogen-containing low molecular weight compounds include amine salts and quaternary ammonium salts. Also, imidazolinium salts, benzimidazolinium salts, pyridinium salts, quinolinium salts can be mentioned. Among them, quaternary ammonium salts and pyridinium salts are preferred. Specific examples include tetramethylammonium = hexafluorophosphate, tetrabutylammonium = hexafluorophosphate, dodecyltrimethylammonium = p-toluenesulfonate, benzyltriethylammonium = hexafluorophosphate, benzyldimethyloctylammonium = hexafluorophos And the compounds described in paragraphs 0021 to 0037 of JP-A 2008-284858 and paragraphs 0030 to 0057 of JP-A 2009-90645, and the like.

The ammonium group-containing polymer may have an ammonium group in its structure, and is preferably a polymer containing 5 to 80 mol% of (meth) acrylate having an ammonium group in a side chain as a copolymerization component. Specific examples include the polymers described in paragraphs 0089 to 0105 of JP-A-2009-208458.

The ammonium group-containing polymer preferably has a reduced specific viscosity (unit: ml / g) value of 5 to 120, preferably 10 to 110, which is determined according to the measuring method described in JP-A 2009-208458. Are more preferred, and those in the range of 15 to 100 are particularly preferred. When the reduced specific viscosity is converted to a weight average molecular weight (Mw), 10,000 to 150,000 are preferable, 17,000 to 140,000 are more preferable, and 20,000 to 130,000 are particularly preferable.

Below, the specific example of an ammonium group containing polymer is shown. (1) 2- (trimethylammonio) ethyl methacrylate = p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90, Mw 45,000)
(2) 2- (trimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 60,000) (3) 2- (ethyldimethylammonium) E) Ethyl methacrylate = p-toluenesulfonate / hexyl methacrylate copolymer (molar ratio 30/70, Mw 45,000) (4) 2- (trimethylammonio) ethyl methacrylate = hexafluorophosphate / 2-ethylhexyl methacrylate Copolymer (molar ratio 20/80, Mw 60,000) (5) 2- (trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60, Mw 70,000) 6) 2- (Butyldimethylammonio) ethyl methacrylate G = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75, Mw 65,000) (7) 2- (butyldimethylammonio) ethyl acrylate = hexafluorophosphate / 3 , 6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 65,000) (8) 2- (butyldimethylammonio) ethyl methacrylate = 13-ethyl-5,8,11-trioxa-1- Heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 75,000) (9) 2- (butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6 -Dioxaheptyl methacrylate / 2-hydroxy-3-methacroyloxypropyl ester Acrylate copolymer (molar ratio 15/80/5, Mw6.5 50,000)

The content of the sensitizing agent is preferably 0.01 to 30% by mass, more preferably 0.1 to 15% by mass, and still more preferably 1 to 10% by mass, in the total solid content of the composition of the present invention.

[Other ingredients]
The composition of the present invention can contain, as other components, surfactants, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic particles, inorganic layered compounds, and the like. Specifically, each component described in paragraphs [0114] to [0159] of JP-A-2008-284817 can be contained.

Lithographic printing plate precursor
The lithographic printing plate precursor of the invention has an image recording layer containing the composition of the invention on a support.
Hereinafter, an on-press developable lithographic printing plate precursor in which the features of the composition of the present invention are remarkably exhibited will be described as an example.

[Image recording layer]
According to one form of the image recording layer, the image recording layer contains an infrared absorber, a polymerizable compound, a polymerization initiator, and at least one of a binder polymer and polymer particles. The image recording layer preferably further contains a radical generation aid and a chain transfer agent.
According to another aspect of the image recording layer, the image recording layer contains an infrared absorber, heat fusible particles, and a binder polymer.
In order to improve the plate inspection properties of the lithographic printing plate precursor, the image recording layer may contain an acid color former.
In the image recording layer, the specific compound according to the present invention can be used as a polymerization initiator. In the image recording layer containing an acid color former, the specific compound according to the present invention can be used as an acid generator for the acid color former.
Respective components such as an infrared absorber, a polymerizable compound, a polymerization initiator, a binder polymer, a polymer particle, a radical generation aid, a chain transfer agent, a thermally fusible particle and the content thereof contained in the image recording layer See the description in the composition of the present invention above.

<Formation of image recording layer>
For example, as described in paragraphs 0142 to 0143 of JP-A-2008-195018, the image recording layer is prepared by dispersing or dissolving the necessary components described above in a solvent to prepare a coating solution, and the coating solution on a support It can form by apply | coating and drying by well-known methods, such as bar-coater application | coating.
A well-known solvent can be used as a solvent. Specifically, for example, water, acetone, methyl ethyl ketone (2-butanone), cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, Propylene glycol monoethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 1-methoxy-2-propanol, 3- Methoxy-1-propanol, methoxymethoxy Tanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone And methyl lactate, ethyl lactate and the like. A solvent may be used individually by 1 type, and may use 2 or more types together. The solid concentration in the coating solution is preferably about 1 to 50% by mass.
The coating amount (solid content) of the image recording layer after coating and drying varies depending on the application, but from the viewpoint of obtaining good sensitivity and good film properties of the image recording layer, it is about 0.3 to 3.0 g / m ^2. Is preferred.

[Subbing layer]
The lithographic printing plate precursor according to the invention preferably has a subbing layer (sometimes referred to as an intermediate layer) between the image recording layer and the support. The undercoat layer strengthens the adhesion between the support and the image recording layer in the exposed area and facilitates the peeling of the image recording layer from the support in the unexposed area. Contribute to improving In addition, in the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, which also has an effect of preventing a decrease in sensitivity due to heat generated by the exposure being diffused to the support.

Examples of the compound used for the undercoat layer include polymers having an adsorptive group capable of adsorbing to the surface of the support and a hydrophilic group. In order to improve the adhesion to the image recording layer, polymers having an adsorptive group and a hydrophilic group, and further having a crosslinkable group are preferred. The compound used for the undercoat layer may be a low molecular weight compound or a polymer. The compounds used in the undercoat layer may be used as a mixture of two or more, if necessary.

When the compound used for the undercoat layer is a polymer, a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group and a monomer having a crosslinkable group is preferred.
Examples of adsorptive groups capable of adsorbing to the surface of a support include phenolic hydroxy group, carboxy group, -PO ₃ H ₂ , -OPO ₃ H ₂ , -CONHSO _2- , -SO ₂ NHSO _2- , -COCH ₂ COCH ₃ Is preferred. The hydrophilic group is preferably a sulfo group or a salt thereof, or a salt of a carboxy group. As the crosslinkable group, an acryl group, a methacryl group, an acrylamide group, a methacrylamide group, an allyl group and the like are preferable.
The polymer may have a crosslinkable group introduced by salt formation of a polar substituent of the polymer and a compound having a polar substituent and a substituent having a counter charge and a compound having an ethylenically unsaturated bond, or other than the above. Further monomers, preferably hydrophilic monomers, may be further copolymerized.

Specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, and an ethylene-based two coupling agent described in JP-A-2-304441. The phosphorus compound which has a heavy bond reactive group is mentioned suitably. Crosslinkable groups (preferably, ethylenically unsaturated bond groups) described in JP 2005-238816, JP 2005-125749, JP 2006-239867, and JP 2006-215263, and a support Low molecular weight or high molecular weight compounds having a functional group that interacts with the surface and a hydrophilic group are also preferably used.
More preferable examples include polymer polymers having an adsorptive group, a hydrophilic group and a crosslinkable group which can be adsorbed on the surface of a support as described in JP-A-2005-125749 and JP-A-2006-188038.

The content of the ethylenically unsaturated bond group in the polymer used for the undercoat layer is preferably 0.1 to 10.0 mmol, more preferably 0.2 to 5.5 mmol, per 1 g of the polymer.
The weight average molecular weight (Mw) of the polymer used for the undercoat layer is preferably 5,000 or more, and more preferably 10,000 to 300,000.

In addition to the above-mentioned compounds for the undercoat layer, the undercoat layer has a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group or a functional group having a polymerization inhibiting ability and a support surface in order to prevent soiling over time. Compounds having a group that interacts with (eg, 1,4-diazabicyclo [2.2.2] octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil, sulfophthalic acid, hydroxy It may contain ethyl ethylenediamine triacetic acid, dihydroxyethyl ethylenediamine diacetic acid, hydroxyethyl imino diacetic acid, and the like.

The subbing layer is applied in a known manner. The coating amount (solid content) of the undercoat layer is preferably 0.1 ~ 100mg / ^{m 2,} and more preferably 1 ~ 30mg / ^{m 2.}

[Protective layer]
The lithographic printing plate precursor of the invention may have a protective layer (sometimes called an overcoat layer) on the image recording layer. The protective layer has a function of preventing the generation of a scratch in the image recording layer and a function of preventing ablation during high-intensity laser exposure, in addition to the function of suppressing the image formation inhibition reaction by oxygen blocking.

The protective layer having such properties is described, for example, in US Pat. No. 3,458,311 and JP-B-55-49729. As the low oxygen permeability polymer to be used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used, and two or more types can be mixed and used as needed. it can. Specifically, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, a water-soluble cellulose derivative, poly (meth) acrylonitrile and the like can be mentioned.
As the modified polyvinyl alcohol, an acid modified polyvinyl alcohol having a carboxy group or a sulfo group is preferably used. Specifically, modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137 can be mentioned.

The protective layer preferably contains an inorganic stratiform compound to enhance the oxygen barrier property. The inorganic stratiform compound is a particle having a thin tabular shape, and, for example, a mica group such as natural mica and synthetic mica, talc represented by the formula: 3MgO.4SiO.H ₂ O, teniolite, montmorillonite, saponite, hekto Light, zirconium phosphate and the like can be mentioned.
The inorganic layered compound preferably used is a mica compound. As the mica compound, for example, a compound represented by the formula: A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂ (wherein A represents at least one selected from the group consisting of K, Na and Ca) And B and C are at least one element selected from the group consisting of Fe (II), Fe (III), Mn, Al, Mg and V, and D is Si or Al. is there. And micas such as natural micas and synthetic micas.

In the mica group, natural micas include muscovite, soda mica, phlogopite, biotite and phlogopite. Non-swelling micas such as fluorine phlogopite KMg ₃ (AlSi ₃ O ₁₀ ) F ₂ and potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) F ₂ as synthetic micas, and Na tetrasilylic mica NaMg _{2. 5} (Si ₄ O ₁₀ ) F ₂ , Na or Li Teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , Montmorillonite Na or Li Hectorite (Na, Li) _1/8 Mg _{2 / 5} Swellable mica such as ₅ Li _1/8 (Si ₄ O ₁₀ ) F ₂ etc. may be mentioned. Furthermore, synthetic smectites are also useful.

Among the mica compounds, fluorine-based swellable mica is particularly useful. That is, swellable synthetic mica has a laminated structure consisting of unit crystal lattice layers having a thickness of about 10 to 15 Å (angstrom, 1 Å = 0.1 nm), and the substitution of metal atoms in lattice is significantly larger than that of other clay minerals. . As a result, the lattice layer lacks positive charge, and in order to compensate for it, cations such as Li ⁺ , Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers. The cations intervening between these layers are called exchangeable cations and can be exchanged with various cations. In particular, in the case where the cation between the layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ion radius is small, and the layer swells significantly with water. In this state, shearing readily cleaves to form a stable sol in water. Swellable synthetic mica is strong in this tendency and is particularly preferably used.

As for the shape of the mica compound, from the viewpoint of diffusion control, the thinner the thickness, the better, and the flat size is better as long as it does not impair the smoothness of the coated surface and the transparency of actinic rays. Therefore, the aspect ratio is preferably 20 or more, more preferably 100 or more, and particularly preferably 200 or more. The aspect ratio is the ratio of the major axis to the thickness of the particle, and can be measured, for example, from a projection of the particle by a micrograph. The larger the aspect ratio, the greater the effect obtained.

The average major axis of the particle diameter of the mica compound is preferably 0.3 to 20 μm, more preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. The average thickness of the particles is preferably 0.1 μm or less, more preferably 0.05 μm or less, and particularly preferably 0.01 μm or less. Specifically, for example, in the case of a swellable synthetic mica which is a representative compound, as a preferred embodiment, the thickness is about 1 to 50 nm and the surface size (long diameter) is about 1 to 20 μm.

The content of the inorganic stratiform compound is preferably 0 to 60% by mass, and more preferably 3 to 50% by mass, with respect to the total solid content of the protective layer. Even when using a plurality of types of inorganic stratiform compounds in combination, it is preferable that the total amount of the inorganic stratiform compounds has the above content. Within the above range, the oxygen barrier property is improved and good sensitivity can be obtained. In addition, it is possible to prevent the deterioration of the inking property.

The protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving the coatability, and inorganic particles for controlling the slipperiness of the surface. The protective layer may contain the specific compound according to the present invention. The protective layer may contain the sensitizing agent described in the image recording layer.

The protective layer is applied in a known manner. The coating amount of the protective layer (solid content) is preferably 0.01 ~ 10g / ^{m 2,} more preferably 0.02 ~ 3g / ^{m 2,} particularly preferably 0.02 ~ 1g / ^{m 2.}

[Support]
The support of the lithographic printing plate precursor according to the present invention can be appropriately selected from known lithographic printing plate precursors. The support is preferably an aluminum plate which has been subjected to surface roughening and anodized by a known method.
The aluminum plate may further be subjected to micropore enlargement treatment or sealing treatment of the anodized film described in JP-A-2001-253181 and JP-A-2001-322365 as required, US Pat. No. 2,714, Surface hydrophilization treatment with an alkali metal silicate as described in the specifications of 066, 3,181,461, 3,280,734 and 3,902,734, US The surface hydrophilization treatment with polyvinyl phosphonic acid or the like as described in each specification of Patents 3,276,868, 4,153,461 and 4,689,272 is appropriately selected. It may be done.
The support preferably has a center line average roughness of 0.10 to 1.2 μm.

The support is, if necessary, an organic polymer compound described in JP-A-5-45885, an alkoxy compound of silicon described in JP-A-6-35174, etc. on the side opposite to the image recording layer. And may have a back coat layer containing

[Method of preparing a lithographic printing plate]
The method of preparing a lithographic printing plate of the present invention comprises the step of imagewise exposing the lithographic printing plate precursor of the present invention (exposure step), and the lithographic printing plate precursor after imagewise exposure on a printing press with printing ink and fountain solution It is preferable to include the step (on-press development step) of removing the unexposed area of the image recording layer according to at least one selected from the above.

[Exposure process]
Image exposure is preferably performed by a method of scanning exposure of digital data with an infrared laser or the like.
The wavelength of the exposure light source is preferably 750 to 1,400 nm. As a light source of 750 to 1,400 nm, a solid state laser and a semiconductor laser emitting infrared rays are preferable. The exposure mechanism may be any of an inner drum system, an outer drum system, a flat bed system, and the like.
The exposure step can be performed by a plate setter or the like by a known method. Alternatively, the lithographic printing plate precursor may be mounted on a printing press using a printing press equipped with an exposure device, and then exposure may be performed on the printing press.

[On-press development process]
In the on-press development step, at least one selected from the printing ink and the dampening water, preferably the printing ink and the dampening solution, on the printing press without subjecting the lithographic printing plate precursor after image exposure to any developing treatment. When water is supplied to start printing (on-press development), the unexposed area of the lithographic printing plate precursor is removed at an early stage during printing, and the hydrophilic support surface is exposed accordingly and a non-image area is formed. Be done. Known printing inks and dampening solutions for lithographic printing are used as printing inks and dampening solutions. Although the printing ink or dampening solution may be supplied first to the surface of the lithographic printing plate precursor, the printing ink is the first to prevent the dampening solution from being contaminated by the removed image recording layer component. It is preferable to supply
Thus, the lithographic printing plate precursor is developed on the offset printing press and used as it is for printing a large number of sheets.

The method of preparing a lithographic printing plate of the present invention may include other known steps in addition to the above steps. Examples of other steps include a step of confirming the position and orientation of the lithographic printing plate precursor before each step, and a confirmation step of confirming a printed image after the on-press development step.

The lithographic printing plate precursor of the present invention can also produce a lithographic printing plate by development processing using a developer by appropriately selecting a binder polymer and the like which are constituents of the image recording layer. The development processing using a developer includes at least one selected from the group consisting of a mode (also referred to as alkali development) using a developer with a high pH of 14 or less containing an alkaline agent, and a surfactant and a water-soluble polymer compound. The embodiment (also referred to as simple development) using a developer having a pH of about 2 to 11 containing a compound of a kind is included. The alkali development and the simple development can be carried out by known methods.

[Salt compound]
The present invention is also a salt compound comprising an organic borate anion and a counter cation, wherein the organic borate anion is an organic borate anion represented by the following formula (II), and the counter cation is a diaryliodonium cation or It relates to a salt compound which is a triarylsulfonium cation.

In the formula (II), Cy 1 and Cy 2, which may be the same or different, each represents a ring structure formed together with a boron atom, an oxygen atom and Y, and Y independently represents —O— or —NR ₅ And R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group.

For details of the organic borate anion represented by the formula (II), the diaryliodonium cation and the triarylsulfonium cation, the above description can be incorporated.

The above salt compounds are compounds useful as a polymerization initiator and an acid generator.

The above salt compounds can be synthesized by known methods. For example, a catechol or salicylic acid derivative and boric acid are reacted in the presence of sodium hydroxide to synthesize a salt composed of an organic borate anion represented by the formula (II) and a counter cation. Next, the salt compound can be synthesized by salt exchange of the counter cation of this salt with a diaryliodonium cation or triarylsulfonium cation according to a conventional method.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. In the polymer compounds, molecular weights are mass average molecular weights (Mw) in terms of polystyrene according to gel permeation chromatography (GPC) method, except for those specified specially, and the ratio of repeating units is molar percentage. Moreover, "part" and "%" mean "mass part" and "mass%" unless there is particular notice.

Examples of the synthesis of specific compounds according to the present invention are described below. Other specific compounds can be similarly synthesized by appropriately changing the raw materials, intermediates and the like.

Synthesis example 1
[Synthesis of Specific Compound I-5]
(Synthesis of Intermediate I-5-Na)
The synthesis scheme of intermediate I-5-Na is shown below.

In a 200 mL three-necked flask, 9.4 g (0.05 mol) of 2-hydroxy-1-naphthoic acid, 1.55 g (0.025 mol) of boric acid, 1.0 g (0.025 mol) of sodium hydroxide and 50 ml of methanol In addition, it was stirred at 80 ° C. for 3 hours. The reaction solution was cooled to room temperature and filtered with washing with methanol to obtain 6.5 g of an intermediate I-5-Na.

(Synthesis of Specific Compound I-5)
The synthesis scheme of the specific compound I-5 is shown below.

In a 200 mL three-necked flask, 3.2 g (0.008 mol) of the above intermediate I-5-Na and 80 ml of a water / acetonitrile = 1/2 (volume ratio) mixed solvent were added, and the mixture was stirred at room temperature. Next, 5.9 g (0.0088 mol) of (4-octyloxyphenyl) (2,4,6-trimethoxyphenyl) iodonium 4-methylbenzenesulfonate (above SM-1) is added and stirred at room temperature for 4 hours did. Thereafter, the precipitated solid was filtered with washing with a mixed solvent of water / acetonitrile = 1/1 (volume ratio) to obtain 5.6 g (yield 80%) of a specific compound I-5.

The structure of the obtained specific compound I-5 was identified by NMR. The identification results are shown below.
¹ H-NMR (400 MHz, heavy dimethyl sulfoxide) δ = 0.85 (m, 3 H), 1.17-1.4 (m, 10 H), 1.67 (m, 2 H), 3.16 (d, 5) 4H), 3.85 (s, 3H), 3.90-4.00 (m, 8H), 4.10 (q, 4H), 6.44 (s, 2H), 6.98 (d, 2H) ), 7.1 (d, 2 H), 7. 38 (t, 2 H), 7.56 (t, 2 H), 7.8-7. 85 (m, 4 H), 8.0 (d, 2 H) , 9.35 (d, 2 H)

Synthesis example 2
[Synthesis of Salt Compound D-2]
(Synthesis of Intermediate SM-5)
The synthesis scheme of intermediate SM-5 is shown below.

In a 3 mL three-necked flask, 217.2 g (1.12 mol) of 5-methyl-2,3,3-trimethylindolenine (SM-1 above) and 3-methoxypropyl tosylate (SM-2 above) 305. 7 g (1.25 mol) was added, and the mixture was stirred at 120 ° C. for 3.5 hours to obtain an intermediate (SM-3 above). The reaction solution was cooled to 60 ° C., 976.3 g of isopropanol was added, and the mixture was stirred at 40 ° C. Further, 265.0 g (0.50 mol) of the above SM-4 and 127.8 g (1.25 mol) of acetic anhydride were added. After 316.6 g (3.13 mol) of triethylamine was dropped, the mixture was stirred at 80 ° C. for 2 hours. The reaction solution was cooled to 5 ° C., 500 g of distilled water was added, and the mixture was stirred for 1 hour. The precipitated solid was collected by filtration, washed with 1000 g of distilled water, and dried with a blower dryer set at 50 ° C. for 8 hours to obtain 336.4 g (0.40 mol) of intermediate SM-5.

(Synthesis of Salt Compound D-2)
The synthesis scheme of the salt compound D-2 is shown below.

In a 200 mL three-necked flask, 4.06 g (0.01 mol) of the above intermediate I-5-Na and 100 ml of a water / acetonitrile = 2/1 (volume ratio) mixed solvent were added, and the mixture was stirred at room temperature. Then, 8.33 g (0.01 mol) of the above intermediate SM-5 was added, and stirred at room temperature for 4 hours. Thereafter, the precipitated solid was filtered with washing with a mixed solvent of water / acetonitrile = 3/1 (volume ratio) to obtain 12.5 g (yield 90%) of a salt compound D-2.

The structure of the obtained salt compound D-2 was identified by NMR. The identification results are shown below.
¹ H-NMR (400 MHz, heavy dimethyl sulfoxide) δ = 1.10 (s, 12 H), 1.83-1.94 (m, 4 H), 2.30 (s, 6 H), 2.88 (s, 4H), 3.20 (s, 6H), 3.29-3.33 (m, 4H), 4.04 (t, 4H), 5.84 (d, 2H), 7.06-7.16 (M, 8H), 7.18-7.25 (m, 6H), 7.37-7.47 (m, 8H), 7.56 (t, 2H), 7.8-7.85 (m) , 4H), 8.0 (d, 2H), 9.35 (d, 2H)

The salt compound D-2 is a salt compound according to the present invention consisting of an organic borate anion and a cyanine dye cation.

Examples 101 to 109 and Comparative Examples 101 to 104
[Preparation of a lithographic printing plate precursor A]

<Preparation of support>
In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) with a thickness of 0.3 mm, a degreasing treatment was performed for 30 seconds at 50 ° C. using a 10 mass% sodium aluminate aqueous solution. After that, the surface of the aluminum plate is grained using three bunched nylon brushes with a diameter of 0.3 mm and pumice-water suspension (specific gravity: 1.1 g / cm ³ ) with a median diameter of 25 μm, and thoroughly washed with water. did. The aluminum plate was etched by immersing it in a 25% by mass aqueous sodium hydroxide solution at 45 ° C. for 9 seconds, and after washing with water, it was further immersed in a 20% by mass aqueous nitric acid solution at 60 ° C. for 20 seconds and rinsed with water. The etching amount of the grained surface was about 3 g / m ² .

Next, electrochemical surface-roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution was a 1 mass% nitric acid aqueous solution (containing 0.5 mass% of aluminum ion), and the liquid temperature was 50 ° C. The AC power supply waveform is electrochemically roughened with a carbon electrode as a counter electrode, using a trapezoidal rectangular wave AC with a time TP of 0.8 msec and a duty ratio of 1: 1 for the current value to reach a peak from zero Did. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak value of the current, and 5% of the current flowing from the power supply was diverted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was an anode. After that, it was rinsed with a spray.

Subsequently, nitric acid electrolysis is carried out using a 0.5 mass% aqueous solution of hydrochloric acid (containing 0.5 mass% of aluminum ion) and an electrolytic solution with a liquid temperature of 50 ° C. under the condition that the aluminum plate has an electric quantity of 50 C / dm ² at the anode Electrochemical roughening treatment was carried out in the same manner as in the above, followed by washing with spray.
Next, using a 15% by weight aqueous solution of sulfuric acid (containing 0.5% by weight of aluminum ion) as an electrolytic solution, form a direct current anodic oxide film of 2.5 g / m ² at a current density of 15 A / dm ² It dried and the support body A was produced. The average pore diameter (surface average pore diameter) in the surface layer of the anodized film was 10 nm.
The measurement of the pore diameter in the surface layer of the anodized film uses an ultra-high resolution SEM (S-900 manufactured by Hitachi, Ltd.), and uses a deposition process or the like to impart conductivity at a relatively low acceleration voltage of 12 V. The surface was observed at a magnification of 150,000 times without application, and 50 pores were randomly extracted to obtain an average value. The standard deviation error was less than ± 10%.

Thereafter, in order to ensure the hydrophilicity of the non-image area, support A was subjected to a silicate treatment at 60 ° C. for 10 seconds using a 2.5 mass% aqueous solution of sodium silicate No. 3 for 10 seconds, and washed to prepare support B. . The adhesion amount of Si was 10 mg / m ² . The center line average roughness (Ra) of the support B was measured using a needle with a diameter of 2 μm and found to be 0.51 μm.

A support C was produced in the same manner as the support A, except that, in the preparation of the support A, the electrolytic solution for forming the direct current anodic oxide film was changed to a 22% by mass aqueous phosphoric acid solution. It was 25 nm when the average pore diameter (surface average pore diameter) in the surface layer of the anodic oxide film was measured by the same method as the above.

Thereafter, in order to ensure the hydrophilicity of the non-image area, the support C is subjected to a silicate treatment at 60 ° C. for 10 seconds using a 2.5% by weight aqueous solution of sodium silicate No. 3 at 60 ° C. Made. The adhesion amount of Si was 10 mg / m ² . The center line average roughness (Ra) of the support D was measured using a needle with a diameter of 2 μm and found to be 0.52 μm.

<Formation of undercoat layer>
An undercoat layer coating solution (1) having the following composition was applied onto the support A so that the dry coating amount would be 20 mg / m ² to form an undercoat layer.

(Undercoat layer coating solution (1))
Polymer (P-1) [below] 0.18 g
・ 0.10 g of hydroxyethyl iminodiacetic acid
・ Water 61.4 g

The synthesis method of the polymer (P-1) is described below.

(Synthesis of Monomer M-1)
In a three-necked flask, 200 parts of Ancamine 1922A (diethylene glycol di (aminopropyl) ether, manufactured by Air Products), 435 parts of distilled water and 410 parts of methanol were added and cooled to 5 ° C. Then 222.5 parts of benzoic acid and 0.025 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (4-OH-TEMPO) are added and 280 parts of methacrylic anhydride are added, It dripped so that the internal temperature of the reaction liquid might be 10 degrees C or less. The reaction solution was stirred at 5 ° C. for 6 hours and then at 25 ° C. for 12 hours, and 70 parts of phosphoric acid was added to adjust the pH to 3.3. The reaction solution was transferred to a stainless beaker, and 3,320 parts of ethyl acetate, 1,120 parts of methyl tert-butyl ether (MTBE) and 650 parts of distilled water were added, and the mixture was vigorously stirred and then allowed to stand. After discarding the upper layer (organic layer), 1,610 parts of ethyl acetate (1.8 L) was added, vigorously stirred and then allowed to stand, and the upper layer was discarded. Further, 1,350 parts of ethyl acetate was added, the mixture was vigorously stirred and allowed to stand, and the upper layer was discarded. Next, 1,190 parts of MTBE were added, the mixture was vigorously stirred and allowed to stand, and the upper layer was discarded. To the obtained aqueous solution, 0.063 parts of 4-OH-TEMPO was added to obtain 12,000 parts of an aqueous solution of monomer M-1 (20.1% by mass in terms of solid content).

(Purification of Monomer M-2)
After adding light ester P-1M (2-metachlorooxyethyl acid phosphate, Kyoeisha Chemical Co., Ltd. product) 420 parts, diethylene glycol dibutyl ether 1,050 parts and distilled water 1,050 parts to a separating funnel and vigorously stirring Let stand. After discarding the upper layer, 1,050 parts of diethylene glycol dibutyl ether was added, and the mixture was vigorously stirred and then allowed to stand. The upper layer was discarded to obtain 13,000 parts of an aqueous solution of monomer M-2 (10.5% by mass in terms of solid content).

(Synthesis of Polymer P-1)
In a three-necked flask, 600.6 parts of distilled water, 33.1 parts of a monomer M-1 aqueous solution and 46.1 parts of the following monomer M-3 were added, and the temperature was raised to 55 ° C. under a nitrogen atmosphere. Next, the following dripping solution 1 is added dropwise over 2 hours, and after stirring for 30 minutes, 3.9 parts of VA-046B (manufactured by Wako Pure Chemical Industries, Ltd.) is added, and the temperature is raised to 80 ° C .; Stir for 5 hours. The reaction solution was returned to room temperature (25 ° C., hereinafter the same), and then 175 parts of 30% by mass aqueous sodium hydroxide solution was added to adjust the pH to 8.3. Next, 0.152 parts of 4-OH-TEMPO was added, and the temperature was raised to 53.degree. 66.0 parts of methacrylic anhydride were added and stirred at 53 ° C. for 3 hours. After returning to room temperature, the reaction solution was transferred to a stainless beaker, and 1,800 parts of MTBE were added. After vigorously stirring, the mixture was allowed to stand and the upper layer was discarded. Similarly, after repeating the washing operation with 1,800 parts of MTBE twice more, 1,700 parts of distilled water and 0.212 parts of 4-OH-TEMPO were added to the obtained aqueous layer to obtain Polymer P-1 as a uniform solution. 41,000 parts (solid content equivalent 11.0%) were obtained. The mass average molecular weight (Mw) made into the polyethylene glycol conversion value by gel permeation chromatography (GPC) method was 200,000.

(Dropping liquid 1)
-132.4 g of the above-mentioned monomer M-1 aqueous solution
-376.9 g of the above aqueous solution of monomer M-2
· Monomer M-3 (above) 184.3 g
Brenmer PME 4000 (manufactured by NOF Corporation) 15.3 g
-VA-046B (manufactured by Wako Pure Chemical Industries, Ltd.) 3.9 g
・ 717.4 g of distilled water

Blemmer PME 4000: methoxy polyethylene glycol methacrylate (the number of repeating oxyethylene units: 90)
VA-046B: 2,2'-azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate

<Formation of image recording layer>
An image recording layer coating solution (1) having the following composition was bar-coated on the undercoat layer, and oven-dried at 100 ° C. for 60 seconds to form an image recording layer having a dry coating amount of 1.0 g / m ² .
The image recording layer coating solution (1) was prepared by mixing and stirring the following photosensitive solution (1) and microgel solution immediately before coating.

<Photosensitive solution (1)>
· Binder polymer (1) [below] 0.240 g
Infrared absorber (D-1) [below] 0.024 g
-Polymerization initiators described in Table A (specific compounds or known compounds) 0.245 g
・ Polymerizable compound 0.192 g
Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, Shin-Nakamura Chemical Co., Ltd. product)
・ Low molecular weight hydrophilic compound 0.062 g
Tris (2-hydroxyethyl) isocyanurate / fluorinated surfactant (1) [below] 0.008 g
・ 2-butanone 1.091 g
1-methoxy-2-propanol 8.609 g

<Micro gel solution>
・ Microgel (1) 2.640 g
・ Distilled water 2.425 g

The structures of the binder polymer (1), the infrared absorber (D-1), and the fluorinated surfactant (1) used in the photosensitive solution (1) are shown below. In the binder polymer (1), the numbers at the lower right of the parentheses of each constituent unit represent a molar ratio.

The preparation method of microgel (1) used for the said microgel liquid is shown below.
<Preparation of Polyvalent Isocyanate Compound (1)>
A suspension of 17.78 g (80 mmol) of isophorone diisocyanate and 7.35 g (20 mmol) of the following polyhydric phenol compound (1) in ethyl acetate (25.31 g) was added with bismuth tris (2-ethylhexanoate) (neostan U). -600, 43 mg of Nitto Kasei Co., Ltd. was added and stirred. When the exotherm had subsided, the reaction temperature was set to 50 ° C., and stirring was performed for 3 hours to obtain an ethyl acetate solution (50% by mass) of the polyvalent isocyanate compound (1).

<Preparation of microgel (1)>
The following oil phase component and aqueous phase component were mixed and emulsified using a homogenizer at 12000 rpm for 10 minutes. After stirring the obtained emulsion at 45 ° C. for 4 hours, 10 mass of 1,8-diazabicyclo [5.4.0] undec-7-ene-octylate (U-CAT SA 102, manufactured by San Apro Ltd.) 5.20 g of% aqueous solution was added, and it stirred at room temperature for 30 minutes, and left still at 45 degreeC for 24 hours. The solid content concentration was adjusted to 20% by mass with distilled water to obtain an aqueous dispersion of microgel (1). The volume average particle size was measured by a light scattering method using a dynamic light scattering type particle size distribution analyzer LB-500 (manufactured by Horiba, Ltd.), and it was 0.28 μm.

(Oil phase component)
(Component 1) Ethyl acetate: 12.0 g
(Component 2) An adduct obtained by adding trimethylolpropane (6 moles) and xylene diisocyanate (18 moles) and adding methyl end-terminated polyoxyethylene (1 mole, repeating number of oxyethylene units: 90) to this 50% by mass ethyl acetate solution, manufactured by Mitsui Chemicals, Inc .: 3.76 g
(Component 3) Polyvalent isocyanate compound (1) (as a 50 mass% ethyl acetate solution): 15.0 g
(Component 4) 65 mass% ethyl acetate solution of dipentaerythritol pentaacrylate (SR-399, manufactured by Sartmar): 11.54 g
(Component 5) 10% ethyl acetate solution of sulfonate type surfactant (Pionin A-41-C, manufactured by Takemoto Yushi Co., Ltd.): 4.42 g

(Water phase component) distilled water: 46.87 g

[Evaluation of lithographic printing plate precursor]
The on-press developability, the heat temporal stability (1), and the printing durability of each of the above lithographic printing plate precursors A were evaluated by the following evaluation methods. The evaluation results are shown in Table A.
<On-machine developability>
The lithographic printing plate precursor was exposed with an external-film laser-mounted Luxel PLATESETTER T-6000 III under the conditions of an outer drum rotational speed of 1,000 rpm, a laser output of 70%, and a resolution of 2400 dpi. The exposed image included a solid image and a 50% dot chart of a 20 μm dot FM screen.
The exposed lithographic printing plate precursor was mounted on a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without development processing. Ecoline 2 (Fuji Film Co., Ltd. product) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) ink ink (DIC Graphics Co., Ltd. product), LITHRONE 26 The dampening water and the ink were supplied by the standard automatic printing start method, and 100 sheets were printed on Tobishi Art Paper (76.5 kg) (manufactured by Mitsubishi Paper Industries Co., Ltd.) at a printing speed of 10,000 sheets per hour. .
The number of sheets of printing paper required until on-press development of the unexposed area of the image recording layer was completed on the printing press and the ink was not transferred to the non-image area was measured and evaluated as on-press developability. The smaller the number, the better the on-press developability.

<Temperature stability over time (1)>
The lithographic printing plate precursor was conditioned at 25 ° C. under a 60% environment for 1 hour and then packaged. The package was then heat aged at 60 ° C. for 4 days. After completion of heat aging, image exposure and on-machine development were carried out in the same manner as in the evaluation of on-press developability, the number of printing paper sheets was measured, and heat aging stability (1) was evaluated. The smaller the number, the better the thermal stability over time.

[Printing durability]
After evaluating the on-press developability, printing was continued. As the image recording layer was gradually worn out as the number of printed sheets increased, the ink density on the printed matter decreased. The number of printed sheets was measured until the value measured by a Gretag densitometer for the halftone dot area rate of 50% halftone dots of the FM screen in the printed matter was 5% lower than the measured value of the 100th printed sheet. The printing durability was evaluated based on relative printing durability, where the number of printed sheets is 50,000 as 100 as shown in the following equation. As the numerical value is larger, the printing durability is better.
Relative printing durability = [(number of copies of target lithographic printing plate precursor) / 50,000] × 100

In Table A, I-1, I-3, I-4, I-6, I-9, I-11, I-12, I-19 and I-24 described in the column of "polymerization initiator" are It is a specific compound of the present invention, and its structure is as shown above. H-1, H-2, H-3 and H-4 are known compounds and the structures are as shown below. In the formula, TfO ⁻ represents trifluoromethanesulfonate anion, and TsO ⁻ represents tosylate anion. Compounds H-1 to H-4 were synthesized by known methods.

From the results described in Table A, it was found that the lithographic printing plate precursor having the image recording layer containing the specific compound according to the present invention as a polymerization initiator had heat stability over time (1), on-press developability, and printing durability. It turns out that everything is excellent.
The lithographic printing plate precursor of the comparative example containing a known polymerization initiator is inferior in any one or more of the heat temporal stability (1), the on-press developability, and the printing durability.

Examples 201 to 209 and Comparative Examples 201 to 204
[Preparation of a lithographic printing plate precursor B]

In the preparation of the lithographic printing plate precursor A, the support B is used instead of the support A, and the following image recording layer coating solution (2) is used instead of the image recording layer coating solution (1). A lithographic printing plate precursor B was produced in the same manner as the above-mentioned lithographic printing plate precursor A except that the following protective layer was formed on the image recording layer. The image recording layer coating solution (2) was prepared by mixing and stirring the following photosensitive solution (2) and microgel solution immediately before coating. The infrared absorber and the polymerization initiator in the image recording layer coating solution (2) used in preparation of each lithographic printing plate precursor are summarized in Table B.

<Photosensitive solution (2)>
· Binder polymer (1) [above]: 0.240 g
Infrared absorber (D-1) [above] or (D-2) [below] 0.024 g
-Polymerization initiator described in Table B (specific compound or known compound) Amount described in Table B-Borate compound 0.020 g
TPB (below)
・ Polymerizable compound 0.192 g
Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, Shin-Nakamura Chemical Co., Ltd. product)
・ Acid color developing agent 0.070 g
2'-Anilino-6 '-(N-ethyl-N-isopentylamino)-
3'-Methylspiro [phthalide-3,9'-xanthene]
(S-205, manufactured by Fukui Yamada Chemical Industry Co., Ltd.)
・ Fluorinated surfactant (1) [above] 0.008 g
・ 2-butanone 1.091 g
1-methoxy-2-propanol 8.609 g

<Micro gel solution>
・ Microgel (1) [above] 2.640 g
・ Distilled water 2.425 g

The structures of the infrared absorber (D-2) and TPB used in the photosensitive solution (2) are shown below. The infrared absorber (D-2) is a salt compound according to the present invention which comprises an organic borate anion and a cyanine dye cation.

<Formation of Protective Layer>
A protective layer coating solution having the following composition was bar-coated on the image recording layer, and oven-dried at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.15 g / m ² .

<Protective layer coating solution>
· Inorganic layered compound dispersion liquid (1) [below] 1.5 g
-Polyvinyl alcohol (CKS 50, manufactured by Japan Synthetic Chemical Industry Co., Ltd.,
Sulfonic acid modified, saponification degree 99 mol% or more, polymerization degree 300) 6 mass% aqueous solution 0.55 g
-Polyvinyl alcohol (PVA-405, manufactured by Kuraray Co., Ltd.,
Saponification degree 81.5 mol%, polymerization degree 500) 6 mass% aqueous solution 0.03 g
Surfactants (polyoxyethylene lauryl ether, Emarex 710,
Nippon Emulsion Co., Ltd. 1% by weight aqueous solution 0.86 g
-Ion exchange water 6.0 g

The preparation method of the inorganic layered compound dispersion liquid (1) is described below.
<Preparation of Inorganic Layered Compound Dispersion (1)>
To 193.6 g of ion-exchanged water, 6.4 g of synthetic mica (Somasif ME-100, manufactured by Coop Chemical Co., Ltd.) was added, and dispersed using a homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

[Evaluation of lithographic printing plate precursor]
For each of the above lithographic printing plate precursors B, the on-press developability, the heat temporal stability (1), and the printing durability were evaluated in the same manner as in the case of the lithographic printing plate precursor A. Furthermore, color development and heat aging stability (2) (ring-like color formation preventing property) were evaluated by the following evaluation methods. The results are shown in Table B.

<Coloring property>
A lithographic printing plate precursor was exposed using a water-cooled 40 W infrared semiconductor laser mounted Trendsetter 3244 VX with an output of 11.7 W, an outer drum rotational speed of 250 rpm, and a resolution of 2,400 dpi (dot per inch, 1 inch = 25.4 mm) did. The exposure was performed under the environment of 25 ° C. and 50% RH.
Immediately after exposure, the color development of the lithographic printing plate precursor was measured. The measurement was performed by a SCE (regular reflection light removal) method using a spectrophotometer CM2600d manufactured by Konica Minolta Co., Ltd. and operation software CM-S100W. The color development was evaluated by the difference ΔL between the L ^* value of the exposed area and the L ^* value of the unexposed area, using the L ^* value (brightness) of the L ^* a ^* b ^* color system. Table B shows the values of ΔL. The larger the value of ΔL, the better the color developability, and the better the plate inspection properties of the lithographic printing plate precursor by color development.

<Temperature stability over time (2) (ring color preventing property)>
The lithographic printing plate precursor was conditioned at 25 ° C. under a 60% environment for 1 hour and then packaged. The package was then heat aged at 60 ° C. for 4 days. After the completion of heat aging, the points colored in a ring shape were visually counted in an area range of 50 × 300 mm. The ring-shaped anti-coloring properties were evaluated by setting the number of coloring points to zero, A to 1-10, B to 10, and C to 10 or more. The planographic printing plate precursor is required to have no ring-like coloring (B and C are indicators for expressing the difference in degree of ring-like coloring).

 

 

In Table B, I-3, I-4, I-4-Na, I-5, I-9, I-9-Na, I-20 and I-32 described in the column of "polymerization initiator" are It is a specific compound of the present invention, and its structure is as shown above. Also, H-1, H-2, H-3 and H-4 are known compounds, and their structures are as shown above. Moreover, the numerical value in parentheses represents the addition amount, and the unit is g.

From the results described in Table B, the lithographic printing plate precursor having the image recording layer containing the specific compound according to the present invention as a polymerization initiator has heat aging stability (1), on-press developability, printing durability, color development It is understood that all of the properties and the heat temporal stability (2) are excellent.
The lithographic printing plate precursor of the comparative example containing a known polymerization initiator is any one of thermal stability (1), on-press developability, printing durability, color development and thermal stability (2) It is inferior in the above.

Examples 301 to 311 and Comparative Examples 301 to 304
[Preparation of a lithographic printing plate precursor C]

In the preparation of the lithographic printing plate precursor A, the support C is used instead of the support A, and an image recording layer coating liquid (3) of the following composition is used in place of the image recording layer coating liquid (1). It was coated and oven-dried at 70 ° C. for 60 seconds to form an image recording layer having a dry coating amount of 0.6 g / m ² , whereby a lithographic printing plate precursor C was produced. The infrared absorbing agent and the polymerization initiator in the image recording layer coating solution (3) used in the preparation of each lithographic printing plate precursor are summarized in Table C.

<Image recording layer coating solution (3)>
· Infrared absorber (D-3) or (D-4) [below] 0.018 g
-Polymerization initiator described in Table C (specific compound or known compound) Amount described in Table C-Borate compound 0.010 g
TPB (above)
Polymer particle water dispersion (1) (22% by mass) [below] 10.0 g
・ Polymerizable compound 1.50 g
SR-399 (made by Sartmar)
・ Acid color developing agent 0.070 g
2'-Anilino-6 '-(N-ethyl-N-isopentylamino)-
3'-Methylspiro [phthalide-3,9'-xanthene]
(S-205, manufactured by Fukui Yamada Chemical Industry Co., Ltd.)
・ Mercapto-3-triazole 0.2 g
・ Byk 336 (manufactured by Byk Chemie) 0.4 g
・ Klucel M (made by Hercules) 4.8 g
・ ELVACITE 4026 (made by Ineos Acrylics)
2.5 g
・ 55.0 g of n-propanol
・ 2-butanone 17.0 g

The infrared absorbers (D-3) and (D-4) used for the image recording layer coating solution (3) and the compounds described in trade names are as follows. The infrared absorber (D-4) is a salt compound of the present invention comprising an organic borate anion and a cyanine dye cation.

SR-399: Dipentaerythritol pentaacrylate Byk 336: Modified dimethylpolysiloxane copolymer (25 mass% xylene / methoxypropyl acetate solution)
Klucel M: hydroxypropyl cellulose (2% by mass aqueous solution)
ELVACITE 4026: Highly branched polymethyl methacrylate (10% by weight 2-butanone solution)

The preparation method of the polymer particle water dispersion liquid (1) used for the said image recording layer coating liquid (3) is shown below.
<Preparation of Polymer Particle Water Dispersion (1)>
A four-necked flask is provided with a stirrer, a thermometer, a dropping funnel, a nitrogen introducing pipe, a reflux condenser, and nitrogen gas is introduced to perform deoxygenation, polyethylene glycol methyl ether methacrylate (PEGMA, average repeating unit of ethylene glycol) Number: 50) 10 g, 200 g of distilled water and 200 g of n-propanol were added, and the mixture was heated until the internal temperature reached 70 ° C. Next, a mixture of 10 g of previously mixed styrene (St), 80 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, 0.4 g of 2,2'-azobisisobutyronitrile was added, and the internal temperature was raised to 80.degree. Subsequently, 0.5 g of 2,2'-azobisisobutyronitrile was added over 6 hours. The polymerization proceeded 98% or more on a molar basis in the stage of reaction for a total of 20 hours, and a polymer particle aqueous dispersion (1) of PEGMA / St / AN = 10/10/80 by weight ratio was prepared. The particle size distribution of the polymer particles had a maximum at a particle size of 150 nm.

The particle size distribution is obtained by taking an electron micrograph of the polymer particles, measuring a total of 5,000 particle sizes on the photograph, and on a logarithmic scale between 0 and the maximum value of the obtained particle size measurements. The frequency of occurrence of each particle size was divided into 50 and plotted. With respect to non-spherical particles, the particle diameter value of spherical particles having the same particle area as the particle area in the photograph is taken as the particle diameter.

[Evaluation of lithographic printing plate precursor]
The heat stability over time (1), the on-press developability, the printing durability, the color development property, and the heat stability over time (2) of each of the above lithographic printing plate precursors C were evaluated in the same manner as in the lithographic printing plate precursor B . The evaluation results are shown in Table C.

 

 

In Table C, I-3, I-3-Na, I-4, I-6, I-6-Na, I-10, I-12, I-19 described in the column of "polymerization initiator". I-22 and I-40 are specific compounds of the present invention, and their structures are as shown above. Also, H-1, H-2, H-3 and H-4 are known compounds, and their structures are as shown above. Moreover, the numerical value in parentheses represents the addition amount, and the unit is g.

From the results described in Table C, the lithographic printing plate precursor having the image recording layer containing the specific compound according to the present invention as a polymerization initiator has heat aging stability (1), on-press developability, printing durability, color development It is understood that all of the properties and the heat temporal stability (2) are excellent.
The lithographic printing plate precursor of the comparative example containing a known polymerization initiator is any one of thermal stability (1), on-press developability, printing durability, color development and thermal stability (2) It is inferior in the above.

Examples 401 to 411 and Comparative Examples 401 to 404
[Preparation of a lithographic printing plate precursor D]

In the preparation of the lithographic printing plate precursor A, the support D is used instead of the support A, and an aqueous solution (4) for coating the image recording layer is coated with a bar instead of the coating solution (1) for the image recording layer, The sheet was oven-dried at 50 ° C. for 60 seconds to form an image recording layer having a dry coating amount of 0.93 g / m ² , to prepare a lithographic printing plate precursor D. The infrared absorber and the polymerization initiator in the image recording layer coating solution (4) used in the preparation of each lithographic printing plate precursor are summarized in Table D.

<Image recording layer coating solution (4)>
・ Infrared absorber (D-5) or (D-6) 0.045 g
-Acid generator described in Table D (specific compound or known compound) Amount described in Table D-Borate compound 0.010 g
TPB (above)
Polymer particle water dispersion (2) [below] 0.693 g
・ Acid color developing agent 0.070 g
2'-Anilino-6 '-(N-ethyl-N-isopentylamino)-
3'-Methylspiro [phthalide-3,9'-xanthene]
(S-205, manufactured by Fukui Yamada Chemical Industry Co., Ltd.)
Glassol E15 0.09 g
(Allied Colloids Manufacturing)
・ ERKOL WX48 / 20 (manufactured by ERKOL) 0.09 g
・ Zonyl FSO100 (manufactured by DuPont) 0.0075 g

The compound described in the trade name used for the image recording layer coating solution (4), the aqueous dispersion of polymer particles (2), and the infrared absorbers (D-5) and (D-6) are as follows. The infrared absorber (D-6) is a salt compound according to the present invention which comprises an organic borate anion and a cyanine dye cation. Glasscol E15: polyacrylic acid ERKOL WX 48/20: polyvinyl alcohol / polyvinyl acetate copolymer Zonyl FSO 100: surfactant polymer particle water dispersion (2): styrene / acrylonitrile copolymer stabilized with anionic wetting agent (Mole ratio 50/50, average particle size 61 nm, solid content about 20%)

[Evaluation of lithographic printing plate precursor]
The heat stability over time (1), the on-press developability, the printing durability, the color development property, and the heat stability over time (2) of each of the above lithographic printing plate precursors D were evaluated in the same manner as in the lithographic printing plate precursor B. . The evaluation results are shown in Table D.

 

 

In Table D, I-1, I-1-Na, I-2, I-4, I-4-Na, I-8, I-16, I-18 described in the column of "acid generator". I-28 and I-37 are specific compounds of the present invention, and their structures are as shown above. Also, H-1, H-2, H-3 and H-4 are known compounds, and their structures are as shown above. Also, the numerical value in parentheses represents the dry coating amount, and the unit is g.

From the results described in Table D, the lithographic printing plate precursor having the image recording layer containing the specific compound according to the present invention as an acid generator has heat aging stability (1), on-press developability, printing durability, color development It is understood that all of the properties and the heat temporal stability (2) are excellent.
The lithographic printing plate precursor of the comparative example containing a known acid generator has any one of thermal stability (1), on-press developability, printing durability, color development and thermal stability (2). It is inferior in the above.

According to the present invention, it is possible to provide a curable composition which has high heat aging stability and cures well by light irradiation.
Furthermore, according to the present invention, it is possible to provide a lithographic printing plate precursor capable of producing a lithographic printing plate having high thermal temporal stability, excellent in on-press developability, and excellent printing durability.
Furthermore, according to the present invention, there is provided a lithographic printing plate precursor capable of producing a lithographic printing plate having high thermal stability over time, being excellent in plate inspection properties and on-press developability, and having excellent printing durability. be able to.
Another object of the present invention is to provide a method of preparing a lithographic printing plate using the above lithographic printing plate precursor.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application (Japanese Patent Application No. 2017-90815) filed on April 28, 2017, the contents of which are incorporated herein by reference.

Claims (16)

A curable composition comprising (A) an organic borate anion represented by the following formula (I), and (B) a salt compound comprising a counter cation.

In formula (I), R ₁ to R _{4, which} may be the same or different, each independently represents a monovalent substituent, or two or more of R ₁ to R ₄ are bonded to each other to form boron The ring structure may be formed together with the atom, the oxygen atom and Y. Y each independently represents -O- or -NR _5- , and R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group Represents The curable composition according to claim 1, wherein the organic borate anion is an organic borate anion represented by the following formula (II).

In the formula (II), Cy 1 and Cy 2, which may be the same or different, each represents a ring structure formed together with a boron atom, an oxygen atom and Y, and Y independently represents —O— or —NR ₅ And R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group. The curable composition according to claim 1, wherein the organic borate anion is an organic borate anion represented by the following formula (III).

In formula (III), R ₇ to R ₁₄ may be the same or different and each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, an arylcarbonyl group, an alkyl ester group, or an alkenyl group. Represents an ester group. Adjacent two of R ₇ to R ₁₄ may be bonded to each other to form a ring structure. The curable composition according to any one of claims 1 to 3, wherein the counter cation is a diaryliodonium cation or a triarylsulfonium cation. The curable composition according to any one of claims 1 to 3, wherein the counter cation is an alkali metal ion, an alkaline earth metal ion or an organic cation having a charge on a nitrogen atom. The curable composition according to any one of claims 1 to 3, wherein the counter cation is a counter cation in a cyanine dye. The curable composition according to any one of claims 1 to 6, further comprising a polymerizable compound and an infrared absorber. The curable composition according to claim 7, wherein the infrared absorber is a cyanine dye. The curable composition according to any one of claims 1 to 8, further comprising an acid color former. The curable composition according to any one of claims 1 to 9, further comprising polymer particles. The curable composition according to any one of claims 1 to 10, further comprising a binder polymer. A curable composition for a lithographic printing plate according to any one of claims 1 to 11. A lithographic printing plate precursor having an image recording layer containing the curable composition according to any one of claims 1 to 12 on a support. The lithographic printing plate precursor as claimed in claim 13, further comprising a protective layer on the image recording layer. A step of imagewise exposing the lithographic printing plate precursor according to claim 13 or 14, a step of removing an unexposed portion of the image recording layer by at least one selected from printing ink and dampening water on a printing press A method of preparing a lithographic printing plate comprising: A salt compound comprising an organic borate anion and a counter cation, wherein the organic borate anion is an organic borate anion represented by the following formula (II), and the counter cation is a diaryliodonium cation or a triarylsulfonium cation Salt compound.

In the formula (II), Cy 1 and Cy 2, which may be the same or different, each represents a ring structure formed together with a boron atom, an oxygen atom and Y, and Y independently represents —O— or —NR ₅ And R ₅ represents a hydrogen atom, an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkoxycarbonyl group, an aryl group or a heteroaryl group.