WO2019013139A1

WO2019013139A1 - Planographic printing original plate, method for preparing planographic printing plate, color developing composition, curable composition, and image forming material

Info

Publication number: WO2019013139A1
Application number: PCT/JP2018/025779
Authority: WO
Inventors: 藤田　明徳; 藤牧　一広; 啓介野越
Original assignee: 富士フイルム株式会社
Priority date: 2017-07-13
Filing date: 2018-07-06
Publication date: 2019-01-17

Abstract

Provided are: a planographic printing original plate having an image recording layer on a support body, wherein the image recording layer contains a compound comprising a cationic part having a radically reactive group and an anion part containing boron atoms, an infrared absorbing agent, and a radically polymerizable compound; a method for preparing the planographic printing plate; a color developing composition; a curable composition; and an image forming material.

Description

Lithographic printing plate precursor, method of making lithographic printing plate, color forming composition, curable composition, and image forming material

The present disclosure relates to a lithographic printing plate precursor, a method of making a lithographic printing plate, a color forming composition, a curable composition, and an image forming material.

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, and the hydrophilic non-image area is a dampening water receiving area (ink non-receiving area). This is a method in which a difference in the adhesivity 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 order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which a lipophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has hitherto been widely used. Usually, after exposing a lithographic printing plate precursor through an original such as a lith film, a portion to be an image portion of the image recording layer is left, and the unnecessary image recording layer is treated with an alkaline developer or an organic solvent. A lithographic printing plate is obtained by plate-making by a method of dissolving and removing with a solvent to expose the hydrophilic support surface to form a non-image area.

In addition, environmental issues related to liquid waste associated with wet processing such as development processing have been highlighted from the growing interest in the global environment.
For the above-mentioned environmental problems, simplification or non-processing of development or plate making is directed. As one of the simple platemaking methods, a method called "on-press development" is performed. That is, after exposing the lithographic printing plate precursor, conventional development is not performed, and the lithographic printing plate precursor is mounted on a printing machine as it is, and removal of the unnecessary portion of the image recording layer is performed at the initial stage of the ordinary printing process.
As a composition used for formation of the conventional lithographic printing plate precursor, what was described in patent document 1 is mentioned, for example.
Moreover, what was described in patent document 2 is mentioned as an antistatic agent in a curable composition.

U.S. Pat. No. 5,956,095 comprises a free radically polymerizable component and an initiator composition capable of producing sufficient free radicals to initiate polymerization of said free radically polymerizable component upon exposure to imaging radiation. A radiation sensitive composition comprising a hydrophobic main chain and a polymer binder having a cation covalently linked to the hydrophobic main chain and a salt pendant group comprising a boron containing anion forming a salt with the cation. The thing is described.

Patent Document 2 describes an antistatic agent characterized by having a polymerizable functional group composed of a specific compound.

Patent Document 1: US Application No. 2008/138741 Specification Patent Document 2: Japanese Patent Application Publication No. 2009-024092

In a lithographic printing plate, a lithographic printing plate excellent in the printable number of plates (hereinafter, also referred to as "printing resistance") is required.
In particular, in recent years, an ink that is cured by irradiation with ultraviolet light (UV) (also referred to as “ultraviolet curable ink”) may be used as the ink in printing.
UV curable inks have high productivity because they can be instantaneously dried, generally have a low solvent content, or have no solvent, so environmental pollution is likely to be reduced, they are not dried by heat, or they are heated Since the image can be formed in a short time of drying, it has the advantage of expanding the range of applications such as printing targets.
Therefore, it is considered that a lithographic printing plate precursor capable of providing a lithographic printing plate excellent in printing durability even when using an ultraviolet curable ink is industrially very useful.
The printing durability in the case of using an ultraviolet curable ink is hereinafter also referred to as "UV printing durability".
As a result of intensive investigations by the present inventors, in the case of a lithographic printing plate precursor formed using the composition described in Patent Document 1, especially when ultraviolet curable ink is used as the ink, the lithographic printing plate obtained is It has been found that there is a problem that the printing durability is insufficient.
In addition, Patent Document 2 does not describe or suggest a lithographic printing plate precursor, nor does it describe or suggest a curable composition using an infrared absorber.

The problem to be solved by the embodiments of the present invention is to provide a lithographic printing plate precursor from which a lithographic printing plate having excellent printing durability can be obtained even when an ultraviolet-curable ink is used in printing.
The problem to be solved by another embodiment of the present invention is to provide a plate making method of a lithographic printing plate which is excellent in printing durability even when an ultraviolet curable ink is used in printing.
In addition, the problem to be solved by the further embodiment of the present invention is a color forming composition excellent in color forming property, a curable composition excellent in chemical resistance after curing, or an image containing these compositions. It is providing a forming material.

Means for solving the above problems include the following aspects.
<1> has an image recording layer on a support,
A lithographic printing plate precursor as described above, wherein the image recording layer comprises a compound having a cation moiety having a radical reactive group and an anion moiety containing a boron atom, an infrared absorber, and a radical polymerizable compound.
<2> The lithographic printing plate precursor as described in <1>, wherein the radical reactive group is a radical polymerizable group or a mercapto group.
The lithographic printing plate precursor as described in said <1> or <2> which is a structure where the said cation part is represented by following formula 1 <3>.

In Formula 1, X represents a group represented by the following Formula 2, a pyridinium group, or an imidazolium group, and Y represents a structure including a radical reactive group.

In Formula 2, R ⁵ to R ⁷ each independently represent an alkyl group or an aryl group, and a plurality of R ⁵ to R ⁷ may combine with each other to form a ring; It represents a binding site to Y.
<4> The lithographic printing plate precursor as described in any one of <1> to <3> above, wherein the molecular weight of the cation part is 59 to 1,000.
<5> The lithographic printing plate precursor as described in any one of <1> to <4> above, wherein the anion moiety is a structure represented by the following formula 3.

In Formula 3, R ¹ to R ⁴ each independently represent an alkyl group or an aryl group.
<6> The lithographic printing plate precursor as described in any one of <1> to <5> above, wherein the anion moiety is a tetraphenylborate anion.
<7> The lithographic printing plate precursor as described in any one of <1> to <6>, wherein the image recording layer further contains a radical polymerization initiator <8> The radical polymerization initiator is an iodonium salt, And the lithographic printing plate precursor as described in said <7> containing at least one of a sulfonium salt.
<9> The lithographic printing plate precursor as described in any one of <1> to <8> above, wherein the image recording layer further comprises an acid color former.
<10> The lithographic printing plate precursor as described in any one of <1> to <9> above, wherein the image recording layer further comprises a polymer particle.
<11> The lithographic printing plate precursor as described in any one of <1> to <10> above, wherein the image recording layer further comprises a binder polymer.
<12> An exposure step of imagewise exposing the lithographic printing plate precursor according to any one of <1> to <11> above to form an exposed area and an unexposed area,
A method for making a lithographic printing plate, comprising an on-press development step of supplying at least one of a printing ink and a dampening solution to remove the unexposed area.
<13> A compound having a cation moiety having a radical reactive group and an anion moiety containing a boron atom,
as well as,
A coloring composition containing an acid color former.
<14> A compound having a cation moiety having a radical reactive group and an anion moiety containing a boron atom,
Infrared absorber, and
A curable composition containing a radically polymerizable compound.
<15> An image forming material comprising the color-forming composition as described in <13> or the curable composition as described in <14>.

According to the embodiment of the present invention, it is possible to provide a lithographic printing plate precursor from which a lithographic printing plate having excellent printing durability can be obtained even when an ultraviolet curable ink is used in printing.
According to another embodiment of the present invention, it is possible to provide a plate making method of a lithographic printing plate which is excellent in printing durability even when an ultraviolet curable ink is used in printing.
Further, according to still another embodiment of the present invention, provided is a color forming composition excellent in color forming property, a curable composition excellent in chemical resistance after curing, or an image forming material comprising these compositions. can do.

The contents of the present disclosure will be described in detail below. The description of the configuration requirements described below may be made based on the representative embodiments of the present disclosure, but the present disclosure is not limited to such embodiments.
In the present specification, “-” indicating a numerical range is used in the meaning including the numerical values described before and after it as the lower limit value and the upper limit value.
Moreover, in the notation of the group (atomic group) in the present specification, the notation not describing substitution and non-substitution includes those having no substituent as well as those having a substituent. For example, the "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
In the present specification, "(meth) acrylic" is a term used in a concept including both acrylic and methacrylic, and "(meth) acryloyl" is a term used as a concept including both acryloyl and methacryloyl. It is.
In addition, the term "step" in the present specification is not limited to an independent step, and may be referred to as the term if the intended purpose of the step is achieved, even if it can not be clearly distinguished from other steps. included. Furthermore, in the present disclosure, “mass%” and “weight%” are synonymous, and “mass part” and “part by weight” are synonymous.
Furthermore, in the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.
Moreover, the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present disclosure use columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (all are trade names manufactured by Tosoh Corporation) unless otherwise noted. It is a molecular weight which is detected using a solvent THF (tetrahydrofuran) and a differential refractometer by a gel permeation chromatography (GPC) analyzer and a polystyrene as a standard substance.
In the present specification, the term "planographic printing plate precursor" encompasses not only a lithographic printing plate precursor but also a disposable plate precursor. In addition, the term "planographic printing plate" includes not only a planographic printing plate prepared by a planographic printing plate precursor through operations such as exposure and development, but also a disposable plate. In the case of the waste plate precursor, the operations of exposure and development are not necessarily required. In addition, a waste printing plate is a planographic printing plate precursor for attaching to a printing plate cylinder which is not used, for example, in the case of printing a part of the paper with a single color or two colors in newspaper printing of color.
Hereinafter, the present disclosure will be described in detail.

(Lithographic printing plate precursor)
A lithographic printing plate precursor according to the present disclosure comprises a compound having an image recording layer on a support, wherein the image recording layer comprises a cation moiety having a radical reactive group and an anion moiety containing a boron atom, an infrared absorber And radically polymerizable compounds.
That is, the lithographic printing plate precursor according to the present disclosure has a support and an image recording layer formed on the support, and the image recording layer has a cation moiety having a radical reactive group and a boron atom. The compound which has an anion part containing, an infrared rays absorber, and a radically polymerizable compound are included.

As a result of intensive investigations conducted by the present inventors, the present inventors have found that a lithographic printing plate precursor according to the present disclosure can provide a lithographic printing plate excellent in printing durability even when using an ultraviolet curable ink in printing. .
Although the detailed mechanism by which the said effect is acquired is unknown, it estimates as follows.
When the image recording layer of the lithographic printing plate precursor according to the present disclosure is exposed to light, it is considered that a radical compound is generated from the anion portion in the compound having a cation portion having a radical reactive group and an anion portion containing a boron atom.
Here, since the anion part and the cation part are bonded or electrically attracted to each other, they are considered to be present relatively close to each other in the image recording layer.
Therefore, the radical compound generated from the anion part and the radical reactive group present in the cation part react rapidly, and the reaction (for example, radical polymerization, thiol-ene reaction, etc.) progressed by the radical species is efficiently performed. As a result, it is presumed that the reactant is efficiently generated and the UV printing resistance is improved.

In addition to the radical compound, it is considered that a compound that functions as a Lewis acid is also generated from the anion moiety.
Therefore, it is considered that a lithographic printing plate having excellent color developability of the image recording layer can be easily obtained by further including in the image recording layer an infrared absorbing agent which develops a color by being decomposed by an acid color former or an acid.
Further, as described above, in the lithographic printing plate precursor according to the present disclosure, it is considered that the radical compound and the radical reactive group react rapidly, that is, the generated radical compound is rapidly consumed.
The consumption of the radical compound is considered to shift the chemical equilibrium of the reaction to the side where the radical compound is generated, thereby increasing the amount of the compound acting as a Lewis acid. Therefore, in the lithographic printing plate precursor according to the present disclosure, in the case where the image recording layer further includes an infrared color-developing agent or an infrared absorbing agent that develops a color upon being decomposed by an acid, a lithographic printing having excellent color development in the exposed area It is thought that the original plate can be easily obtained.
By being excellent in the coloring property of the exposed part of an image recording layer, the lithographic printing plate precursor which is excellent in the visibility of an exposure location is obtained.

The following formula schematically represents the above mechanism.
When a lithographic printing plate precursor using the following compound A-1 is exposed as the compound having the cation portion having a radical reactive group and the anion portion containing a boron atom, the reaction described in, for example, Formula P-1 is It is guessed to happen.
Specifically, it considered and phenyl radicals from tetraphenylborate anion compound A-1 which caused the 1 electron transfer by exposure, is BPh ₃ acting as a Lewis acid generated. In the present disclosure, “Ph” represents a phenyl group unless otherwise specified.
The above-mentioned phenyl radical reacts with the ethylenically unsaturated group present in the cation part in the compound A-1, and the polymerization reaction proceeds.
Since the cation part and the anion part in the compound A-1 are bonded or exist at relatively close positions due to the electric attraction even if they are not bonded, when the above reaction proceeds efficiently Conceivable.

<Image recording layer>
The image recording layer in the present disclosure is a compound having a cation portion having a radical reactive group and an anion portion containing a boron atom (hereinafter, also referred to as a “specific compound”), an infrared absorber, and a radical polymerizable compound. Including.
The image recording layer used in the present disclosure is preferably a negative image recording layer, and more preferably a water-soluble or water-dispersible negative image recording layer.
In addition, the image recording layer used in the present disclosure preferably further contains a polymerization initiator and a polymerizable compound from the viewpoint of printing durability and photosensitivity.
The lithographic printing plate precursor according to the present disclosure is preferably removable from the unexposed area of the image recording layer by at least one of dampening water and printing ink, from the viewpoint of on-press developability.
The details of each component contained in the image recording layer will be described below.

[Specific compound]
The specific compound has a cation moiety having a radical reactive group and an anion moiety containing a boron atom.
The cation part and the anion part may be bound or dissociated in the image recording layer.
In the present disclosure, the cation moiety represents a covalently linked atomic group containing a cationic group such as quaternary ammonium group, pyridinium group, imidazolium group and the like.
In addition, the anion moiety represents a covalently linked atomic group including an anionic structure such as a borate anion structure.

-Cation part-
The cation moiety is preferably a compound having a cationic group and a radical reactive group.

<< Cationic group >>
The cationic group is not particularly limited, but is preferably a cationic group having a positive charge on a nitrogen atom from the viewpoint of the thermal stability of the cation moiety, and is preferably a quaternary ammonium group, a pyridinium group, or an imidazo group. More preferably, it is a lithium group, and more preferably a quaternary ammonium group.

<< Radical Reactive Groups >>
The radically reactive group is not particularly limited, but is preferably a radically polymerizable group or a mercapto group.
From the viewpoint of the polymerization reaction with the radically polymerizable compound, the radically reactive group is preferably a radically polymerizable group. Further, from the viewpoint of suppression of reaction inhibition by oxygen, the radical reactive group is preferably a mercapto group.
The radically polymerizable group is preferably a group having an ethylenically unsaturated group from the viewpoint of UV printing resistance, and a (meth) acryloxy group, a (meth) acrylamide group, or a vinylphenyl group is preferable.
The cation moiety may have a plurality of radical reactive groups, but preferably has only one radical reactive group.

<< Structure Represented by Formula 1 >>
Further, in the present disclosure, the cation moiety is preferably a structure represented by the following formula 1.

In Formula 2, R ⁵ to R ⁷ each independently represent an alkyl group or an aryl group, and a plurality of R ⁵ to R ⁷ may combine with each other to form a ring; It represents a binding site to Y.

In formula 1, from the viewpoint of UV printing resistance, X is preferably a group represented by formula 2.
In the formula 2, from the viewpoint of UV printing resistance, R ⁵ to R ⁷ each independently preferably represent an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, and preferably 1 to 4 carbon atoms. It is more preferable that it represents an alkyl group of 6 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, still more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group.
Further, it is preferable that at least two of R ⁵ to R ⁷ represent an alkyl group, and it is more preferable that all three represent an alkyl group.

In Formula 1, Y represents a structure containing a radical reactive group, and is preferably a structure represented by the following Formula Y-1.

In Formula Y-1, L ¹ represents a divalent linking group, P ¹ represents a radical reactive group, and ● represents a bonding site to X in Formula 1.
In formula Y-1, L ¹ is preferably an alkylene group, an arylene group or a group represented by a bond thereof, and is preferably an alkylene group having 2 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms or a bond thereof Are more preferably groups represented by the formula, an alkylene group having 2 to 6 carbon atoms, a phenylene group or a group represented by a bond thereof is more preferred, and an alkylene group having 2 to 6 carbon atoms is particularly preferred.
In Formula Y-1, P ¹ represents a radical reactive group, preferably a radical polymerizable group or a mercapto group, and more preferably a radical polymerizable group.
As a radically polymerizable group, a group containing an ethylenically unsaturated group is preferable, and a group containing a terminal ethylenically unsaturated group is more preferable, and a (meth) acryloxy group, a (meth) acrylamide group, or a vinylphenyl group is further added preferable.

<< molecular weight >>
The molecular weight of the cation moiety is preferably 59 to 1,000, more preferably 90 to 300, and still more preferably 100 to 250.
The molecular weight of the cation moiety is determined by arithmetic calculation from the structure determination of the cation moiety.

-Anion part-
The anion moiety preferably has a negative charge on a boron atom, more preferably a quaternary boron anion, still more preferably a tetraaryl borate anion, and particularly preferably a tetraphenyl borate anion.
In the present disclosure, the tetraphenyl borate anion refers to a quaternary boron anion represented by the following formula.

The four aryl groups in the tetraaryl borate anion or the four phenyl groups in the tetraphenyl borate anion may each independently have a substituent, and preferred substituents include a halogen atom, an alkyl group, and a haloalkyl. Groups, alkoxy groups, cyano groups and the like. In the present disclosure, a haloalkyl group refers to a group in which all hydrogen atoms of an alkyl group are substituted by halogen atoms.

<< Structure Represented by Formula 3 >>
The anion moiety is preferably a structure represented by the following formula 3.

In Formula 3, R ¹ to R ⁴ each independently represent an alkyl group or an aryl group.
In Formula 3, R ¹ to R ⁴ are each independently preferably an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, methyl Groups or phenyl groups are more preferred, with phenyl groups being particularly preferred.
The said alkyl group may be substituted, and a halogen atom, an alkoxy group etc. are mentioned as a preferable substituent.
The aryl group may be substituted, and preferred examples of the substituent include a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group and a cyano group.
In Formula 3, at least two of R ¹ to R ⁴ are preferably phenyl groups, more preferably at least three are phenyl groups, and still more preferably all four are phenyl groups.

-Specific examples of specific compounds-
Hereinafter, although the specific example of the specific compound suitably used in this indication is described, it is not limited to this.
In the following structural formulae, Me represents a methyl group, and Ph represents a phenyl group.
Moreover, in each compound, although described in the form which the anion part and the cation part dissociated, you may couple | bond these.

-Molecular weight of specific compound-
The molecular weight of the specific compound according to the present disclosure is preferably 100 to 1000, more preferably 300 to 800, and still more preferably 400 to 600.

-Content of specific compound-
The image recording layer in the present disclosure may contain the specific compound singly or in combination of two or more.
The content of the specific compound in the present disclosure is preferably 0.001% by mass to 30% by mass, and more preferably 0.01% by mass or more, with respect to the total mass of the image recording layer, from the viewpoint of improving UV printing resistance. It is more preferably 10% by mass, further preferably 0.1% by mass to 5% by mass.

[Infrared absorber]
The image recording layer in the present disclosure contains an infrared absorber.
The infrared absorber has a function of converting the absorbed infrared ray into heat and a function of being excited by the infrared ray to perform electron transfer and / or energy transfer to a polymerization initiator described later. The infrared absorber used in the present disclosure is preferably a dye or a pigment having an absorption maximum at a wavelength of 700 nm to 1,400 nm, more preferably a dye.
As the dye, those described in paragraphs 0082 to 0088 of JP-A-2014-104631 can be used.
The average particle diameter of the pigment is preferably 0.01 μm to 1 μm, and more preferably 0.01 μm to 0.5 μm. To disperse the pigment, known dispersion techniques used for ink production, toner production, etc. can be used. The details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

The infrared absorber is preferably a compound having a cyanine structure, more preferably a compound having a cyanine structure having an indolenine nucleus, and particularly preferably an electron-attracting group such as a halogen atom at the indolenine nucleus. It is a substituted compound.

Furthermore, as the infrared absorber, an infrared absorber which is decomposed by an acid to develop color is preferably used.
Since the compound which acts as a Lewis acid is also generated from the anion part in the specific compound, the image recording layer in the planographic printing plate precursor according to the present disclosure contains an infrared absorbing agent which is colored by decomposition by acid. It is easy to obtain a lithographic printing plate excellent in color development of

As specific examples of the infrared absorbing agent which is colored by being decomposed by an acid, mother nucleus structures A-1 to A-54, counter anions B-1 to B-10 and counter cations C-1 to C-3 can be mentioned. The present invention is not limited to this. In addition, specific examples of the compound represented by the formula 1 include mother nucleus structures A-1 to A-9, A-11 to A-20 and A-22 to A-54, and counter anions B-1 to B-. 10 is a compound in which each of 10 and 10 is combined, and a compound in which each of mother nucleus structures A-10 and A-21 and counter cations C-1 to C-3 is combined.

The method for producing the compound represented by the formula 1 is not particularly limited, and the compound can be produced with reference to known methods for producing cyanine dyes. In addition, the method described in WO 2016/027886 can also be suitably used.

The infrared absorber may be used alone or in combination of two or more.
The content of the infrared absorber is preferably 0.05% by mass to 30% by mass, more preferably 0.1% by mass to 20% by mass, and more preferably 0.2% by mass to 10% by mass with respect to the total mass of the image recording layer. % Is particularly preferred.

[Radical polymerizable compound]
The image recording layer in the present disclosure contains a radically polymerizable compound.
The radically polymerizable compound used in the image recording layer is preferably an addition polymerizable compound (ethylenically unsaturated compound) having at least one ethylenically unsaturated bond. 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 radically polymerizable compounds can have chemical forms, such as, for example, monomers, prepolymers, ie, dimers, trimers or oligomers, or mixtures 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. In addition, 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) isocyanurate modified triacrylate, 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. 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, There are diethylene triamine tris acrylamide, xylylene bis acrylamide, xylylene bis methacrylamide and the like.

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 content of the radically polymerizable compound is preferably 5% by mass to 75% by mass, more preferably 10% by mass to 70% by mass, particularly preferably 15% by mass to 60% by mass, based on the total mass of the image recording layer. It is.

[Radical polymerization initiator]
The image recording layer used in the present disclosure preferably contains a radical polymerization initiator. The radical polymerization initiator used in the image recording layer is a compound which generates radical species by light and / or heat energy, and is a known thermal polymerization initiator, a compound having a small bond dissociation energy, photopolymerization initiation It can be selected appropriately from agents and the like.
As a radical polymerization initiator, an infrared photosensitive polymerization initiator is preferable.
Examples of radical polymerization initiators include (a) organic halides, (b) carbonyl compounds, (c) azo compounds, (d) organic peroxides, (e) metallocene compounds, (f) azide compounds, (g) ) Hexaarylbiimidazole compounds, (h) organic borate compounds, (i) disulfone compounds, (j) oxime ester compounds, (k) onium salt compounds.

As the organic halide (a), for example, compounds described in paragraphs 0022 to 0023 of JP-A-2008-195018 are preferable.
(B) As a carbonyl compound, the compound as described in stage 0024 of Unexamined-Japanese-Patent No. 2008-195018 is preferable, for example.
Examples of the azo compound (c) include the azo compounds described in JP-A-8-108621.
As the organic peroxide (d), for example, a compound described in paragraph 0025 of JP-A-2008-195018 is preferable.
(E) As a metallocene compound, the compound as described in Paragraph 0026 of Unexamined-Japanese-Patent No. 2008-195018 is preferable, for example.
Examples of the azide compound (f) include compounds such as 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.
(G) As a hexaaryl biimidazole compound, the compound as described in stage 0027 of Unexamined-Japanese-Patent No. 2008-195018 is preferable, for example.
As the organic borate compound (h), for example, compounds described in paragraph 0028 of JP-A-2008-195018 are preferable.
Examples of the disulfone compound (i) include compounds described in JP-A-61-166544 and JP-A-2002-328465.
As the oxime ester compound (j), for example, compounds described in paragraphs 0028 to 0030 of JP-A-2008-195018 are preferable.

Among the radical polymerization initiators, an oxime ester and an onium salt are mentioned as more preferable ones from the viewpoint of curability, and onium salts such as iodonium salts, sulfonium salts and azinium salts are more preferable, iodonium salts and sulfonium salts It is particularly preferred to include at least one of For use in 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 disclosure 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 above iodonium salt and sulfonium salt are replaced with a counter anion such as hexafluorophosphate from the viewpoint of the heat temporal stability of the lithographic printing plate precursor, and a sulfonamide anion structure and ring structure directly bonded to the ring structure as a counter anion And an organic anion having at least one member selected from the group consisting of a sulfoneimide anion structure directly bonded to
The heat aging stability of the lithographic printing plate precursor refers to the property that the developability of the lithographic printing plate precursor is excellent even when stored at high temperature (for example, storage at 60 ° C. for 4 days).

The sulfonamide anion structure is an anion structure represented by the following formula. In the following structures, each * independently represents a binding site to another structure. Furthermore, it is more preferable that at least one * be directly bonded to the ring structure, and both * be directly bonded to the ring structure.

The sulfone imide anion structure is an anion structure represented by the following formula. In the following structures, each * independently represents a binding site to another structure. Furthermore, it is more preferable that at least one * be directly bonded to the ring structure, and both * be directly bonded to the ring structure.

The organic anion is one in which a negative charge is present on a nitrogen atom, but it may also be described, for example, by a resonance structure, and may be a structure in which a negative charge is present other than a nitrogen atom. For example, the resonance structure in the sulfoneimide anion is described below as an example.

The ring structure in the sulfonamide anion structure directly bonded to the ring structure or the sulfoneimide anion structure directly bonded to the ring structure is not particularly limited, but an aromatic hydrocarbon ring, an alicyclic hydrocarbon ring, a heterocyclic ring, etc. It can be mentioned.

The aromatic hydrocarbon ring includes an aromatic hydrocarbon ring having 6 to 20 carbon atoms, and specific examples include benzene, naphthalene, anthraquinone and the like.
The alicyclic hydrocarbon ring includes an alicyclic hydrocarbon ring having 3 to 30 carbon atoms. The alicyclic hydrocarbon ring may have an unsaturated bond.
The heterocycle is a heterocycle 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. The heterocycle may be saturated or unsaturated. The heterocycle is preferably an aromatic heterocycle.
Examples of the heterocyclic ring include pyridine ring, pyrimidine ring, pyrroline ring and the like.

The organic anion in the present disclosure is preferably an organic anion represented by the following formula I. In addition, although the organic anion which concerns on this indication can be represented by several resonance structural formula according to an electronic configuration like general anion, in this specification, as shown below, the negative charge on a nitrogen atom is shown. It describes using the resonance structural formula which has.

In Formula I, Cy represents an aryl group, a heteroaryl group, or an alicyclic group which may have an unsaturated bond, and X represents an alkyl group, an aryl group, a heteroaryl group, SO ₂ ^Ra , SOR ^b , COR ^c , PO ₃ R ^d , PO (R ^e ) (R ^f ), or H. R ^a , R ^b , R ^c , R ^d , R ^e and R ^f each represent a group selected from the group consisting of an alkyl group, an alkoxy group, an aryl group, a heteroaryl group, and H. R ^a , R ^b , R ^c , R ^d , R ^e or R ^f may combine with Cy to form a ring.

The aryl group represented by Cy is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and still more preferably an aryl group having 6 to 10 carbon atoms.
As an example of an aryl group, a phenyl group, a naphthyl group, etc. are mentioned, A phenyl group etc. are preferable.

The heteroaryl group represented by Cy is a group formed from a heterocycle containing at least one hetero atom selected from an oxygen atom, a sulfur atom and a nitrogen atom. The heterocycle is preferably a 5- to 8-membered ring, more preferably a 5- to 6-membered ring. Examples of the heteroaryl group include pyridyl group, pyrimidyl group, pyrrolyl group, furanyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, indolyl group, quinolinyl group, oxadiazolyl group, benzoxazolyl group and the like. .

The alicyclic group represented by Cy is a group formed from an alicyclic ring having 3 to 30 carbon atoms, preferably an alicyclic ring having 4 to 9 carbon atoms. The alicyclic ring may be monocyclic or polycyclic. In addition, the alicyclic ring may have an unsaturated bond.
Examples of the alicyclic group which may have an unsaturated bond include cyclopentanyl group, cyclopentadienyl group, cyclohexenyl group, cyclohexadienyl group, cycloheptanyl group, cycloheptadienyl group, norbornene group and the like It can be mentioned.

The above aryl group, heteroaryl group or heteroaryl group may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an aryl group, a carbonyl group and an alkoxycarbonyl group. , Cyano group, amido group, urea group, urethane group, alkenyl group, allyl group, acryl group, acryl group, methacryl group, acrylamide group, methacrylamide group, a group formed by combining one or more of halogen atoms, etc. Be

In Formula I, the alkyl group represented by X is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and still more preferably an alkyl group having 1 to 8 carbon atoms. It may be linear or branched. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, octyl and tert-octyl Groups, nonyl groups, decyl groups, dodecyl groups, ethylhexyl groups and the like.
The alkyl group is preferably a methyl group, an ethyl group or a tert-butyl group.

The aryl group and heteroaryl group represented by X in Formula (I) have the same meanings as the aryl group and heteroaryl group represented by Cy in Formula (I), and the preferred range is also the same.

The alkyl group, aryl group and heteroaryl group represented by R ^a , R ^b , R ^c , R ^d , R ^e and R ^f in the formula I are the alkyl groups represented by X in the formula (I) It is synonymous with a group, an aryl group, and a heteroaryl group, and its preferable range is also synonymous.

The alkoxy group represented by R ^a , R ^b , R ^c , R ^d , R ^e and R ^f in the formula I is preferably an alkoxy group having 1 to 20 carbon atoms, and the alkoxy group having 1 to 16 carbon atoms is preferably More preferred is an alkoxy group having 1 to 12 carbon atoms.

The alkyl group, aryl group or heteroaryl group represented by X above may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an aryl group and a carbonyl group. , Alkoxycarbonyl group, cyano group, amido group, urea group, urethane group, alkenyl group, allyl group, acryl group, acryl group, methacryl group, acrylamide group, methacrylamide group, halogen atom, or two or more of them are combined Groups and the like.
In addition, the alkyl group, alkoxy group, aryl group or heteroaryl group represented by ^Ra , ^Rb , ^Rc , ^Rd , ^Re , ^Rf and ^Rg may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an aryl group, a carbonyl group, an alkoxycarbonyl group, a cyano group, an amido group, a urea group, a urethane group, an alkenyl group, an allyl group, an acrylic group and a methacryl group. Examples thereof include groups in which one or two or more of a group, an acrylamide group, a methacrylamide group, and a halogen atom are combined.

As X, an alkyl group, a heteroaryl group, SO ₂ R ^a , SOR ^b , COR ^c , PO ₃ R ^d , PO (R ^e ) (R ^f ) or H is preferable.
R ^a , R ^b , R ^c , R ^d , R ^e or R ^f may combine with Cy to form a ring. When X is SO ₂ R ^a , R ^a is H (hydrogen atom), and R ^a is bonded to Cy to form a ring, H as R ^a is eliminated and SO ₂ is C y It represents that it combines with.

The organic anion in the present disclosure is preferably an organic anion represented by the following formula II.

In the formula II, Cy represents an aryl group, a heteroaryl group, an alicyclic group which may have an unsaturated bond, R ^a represents a group consisting of an alkyl group, an alkoxy group, an aryl group, a heteroaryl group, and H Represents a group selected from R ^a may combine with Cy to form a ring.

In Formula II, an aryl group represented by Cy, a heteroaryl group, and an alicyclic group which may have an unsaturated bond are the aryl group represented by Cy in Formula I, a heteroaryl group, and It is synonymous with the alicyclic group which may have an unsaturated bond, and its preferable range is also synonymous.

The aryl group, heteroaryl group or heteroaryl group represented by Cy above may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an aryl group, a carbonyl Or one or more of a group, alkoxycarbonyl group, cyano group, amido group, urea group, urethane group, alkenyl group, allyl group, acryl group, acryl group, methacryl group, acrylamide group, methacrylamide group, halogen atom And the like.
In addition, the alkyl group, alkoxy group, aryl group or heteroaryl group represented by R ^a may have a substituent, and examples of the substituent include an alkyl group, an alkoxy group, an aryloxy group, an aryl Group, carbonyl group, alkoxycarbonyl group, cyano group, amido group, urea group, urethane group, alkenyl group, allyl group, acryl group, acryl group, methacryl group, acrylamide group, methacrylamide group, halogen atom, one or more of And the like.

The organic anion in the present disclosure is preferably an organic anion represented by the following Formula III or Formula IV.

In Formula III, R ₁ to R ₁₀ each independently represent a hydrogen atom or a monovalent substituent.
In formula IV, R ₁₁ to R ₁₄ each independently represent a hydrogen atom or a monovalent substituent.

The monovalent substituent represented by R ₁ to R ₁₀ in the formula III is not particularly limited as long as the effects of the present disclosure are not impaired, and examples thereof include an alkyl group (having 1 to 12 carbon atoms). Preferred is an alkyl group, more preferred is an alkyl group having 1 to 10 carbon atoms, and still more preferred is an alkyl group having 1 to 8 carbon atoms.The alkyl group may be linear or branched, alkoxy group (alkoxy group) The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, still more preferably an alkyl group having 1 to 8 carbon atoms, and the alkyl group may be linear or branched. And aryloxy groups (the aryl group in the aryloxy group is preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms, and 6 to 10 carbon atoms. An aryl group is more preferable), an aryl group (an aryl group having 6 to 20 carbon atoms is preferable, an aryl group having 6 to 15 carbon atoms is more preferable, and an aryl group having 6 to 10 carbon atoms is further preferable), a carbonyl group And the alkoxycarbonyl group (The alkyl group in the alkoxy group is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and still more preferably an alkyl group having 1 to 8 carbon atoms. It may be linear or branched), cyano group, amido group, urea group, urethane group, alkenyl group (preferably, alkenyl group having 2 to 15, more preferably 2 to 6 carbon atoms), allyl group, acrylic Group, methacryl group, acrylamide group, methacrylamide group, halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom) Be mentioned include groups composed by combining the two or more kinds.
The group mentioned as the monovalent substituent may be further substituted by another group.

In the formula III, as the group represented by R ₁ to R ₁₀ , a hydrogen atom and the above-mentioned monovalent substituent are preferable, and an alkyl group, a halogen group and an alkoxycarbonyl group are more preferable.

In Formula IV, as the monovalent substituent represented by R ₁₁ to R ₁₄ , for example, an alkyl group (an alkyl group having 1 to 12 carbon atoms is preferable, an alkyl group having 1 to 10 carbon atoms is more preferable, carbon The alkyl group is more preferably an alkyl group of 1 to 8. The alkyl group may be linear or branched, or an alkoxy group (the alkyl group in the alkoxy group is preferably an alkyl group having 1 to 12 carbon atoms, 1 to 12 carbon atoms). An alkyl group of 10 is more preferable, and an alkyl group having 1 to 8 carbon atoms is further preferable.The alkyl group may be linear or branched, and an aryloxy group (an aryl group in the aryloxy group has 6 carbon atoms) An aryl group of -20 is preferable, an aryl group having 6 to 15 carbon atoms is more preferable, and an aryl group having 6 to 10 carbon atoms is still more preferable, an aryl group (an aryl group having 6 to 20 carbon atoms) Group is preferable, an aryl group having 6 to 15 carbon atoms is more preferable, and an aryl group having 6 to 10 carbon atoms is still more preferable, an aryl group (an aryl group having 6 to 20 carbon atoms is preferable, 6 to 15 carbon atoms). The aryl group is more preferably an aryl group having 6 to 10 carbon atoms.), A carbonyl group or an alkoxycarbonyl group (the alkyl group in the alkoxy group is preferably an alkyl group having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms). The alkyl group is more preferably an alkyl group having 1 to 8 carbon atoms, which may be linear or branched), cyano group, amido group, urea group, urethane group, alkenyl group (preferably Is an alkenyl group having a carbon number of 2 to 15, more preferably 2 to 6), an allyl group, an acryl group, a methacryl group, an acrylamide group, methacrylamide De group, a halogen atom (such as fluorine atom, chlorine atom, bromine atom or iodine atom) one or more are combined comprising group can be mentioned.
The group mentioned as the monovalent substituent may be further substituted by another group.

In the formula IV, as a group represented by R ₁₁ to R ₁₄ , a hydrogen atom and the above-mentioned monovalent substituent are preferable, and an alkyl group, a halogen group and an alkoxycarbonyl group are more preferable.

Also included in Formula III are those comprising more than one sulfoneimide anion structure via any of R ₁ -R ₁₀ .

Specific examples of the organic anion are shown below as an anion moiety, but the present disclosure is not limited thereto. In the following specific examples, Ph represents a phenyl group, Me represents a methyl group, and Et represents an ethyl group.

The radical polymerization initiator may be used alone or in combination of two or more.
The content of the radical polymerization initiator is preferably 0.1% by mass to 50% by mass, more preferably 0.5% by mass to 30% by mass, particularly preferably 0.8% by mass, with respect to the total mass of the image recording layer. It is mass% to 20 mass%.

[Acid color developing agent]
The image recording layer used in the present disclosure preferably contains an acid color former.
The “acid color former” used in the present disclosure means a compound having a property of developing a color by heating in a state where an electron accepting compound (for example, a proton such as an acid) is received. As an acid color developing agent, particularly, it has a partial skeleton such as lactone, lactam, sultone, spiropyran, ester, amide and the like, and is a colorless which rapidly opens or cleaves the partial skeleton when contacted with an electron accepting compound. Compounds are preferred.

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,

In addition, 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.

Among the above, the acid color former used in the present disclosure 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 commercially available product as an acid color developing agent, such as 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 (above, Fukui Yamada Chemical Industry Co., Ltd.), ORANGE-DCF, Vermilion-DCF, PINK-DCF, RED-DCF, BLMB, CVL, GREEN-DCF , TH-107 (manufactured by Hodogaya Chemical Co., Ltd.), ODB, ODB-2, ODB-4, ODB-250, ODB-Black XV, Blue-63, Blue-502, GN-169, GN-2, Gre n-118, Red-40, Red-8 (manufactured by Yamamoto Chemicals Co., Ltd.), crystal violet lactone (manufactured by Tokyo Kasei Kogyo 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 the visible light absorptivity of the formed film is good.

These acid color formers may be used alone or in combination of two or more.
The content of the acid color former is preferably 0.01% by mass to 30% by mass, more preferably 0.05% by mass to 25% by mass, particularly preferably 0.1% by mass, based on the total mass of the image recording layer. % To 20% by mass.

[Polymer particles]
In order to improve the on-press developability of a lithographic printing plate precursor, the image recording layer may contain polymer particles. The polymer particles are preferably polymer particles that can convert the image recording layer to hydrophobic when heat is applied. The polymer particles are at least one selected from hydrophobic thermoplastic polymer 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 hydrophobic thermoplastic polymer particles, for example, Research Disclosure No. 1 of January 1992. No. 33,303, hydrophobic thermoplastic polymer particles described in JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250 and EP931647 are suitable. Can be mentioned.
Specific examples of the polymer constituting the hydrophobic thermoplastic polymer particles 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 average particle size of the hydrophobic thermoplastic polymer particles is preferably 0.01 μm 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 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, and the like.

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 some of the components of the image recording layer 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 image recording layer.
The average particle diameter of the microcapsules or microgel is preferably 0.01 μm to 3.0 μm, more preferably 0.05 μm to 2.0 μm, and particularly preferably 0.10 μm to 1.0 μm. Within this range, good resolution and stability over time can be obtained.
The content of the polymer particles is preferably 5% by mass to 90% by mass with respect to the total mass of the image recording layer.

[Binder polymer]
The image recording layer used in the present disclosure preferably contains a binder polymer. As a binder polymer, (meth) acrylic resin, polyvinyl acetal resin, and a polyurethane resin are preferable. As used herein, "(meth) acrylic" includes "acrylic" and "methacrylic".

Among them, as the binder polymer, known binder polymers used in the image recording layer of a lithographic printing plate precursor can be suitably used. 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 resins, polyester resins, synthetic rubbers and natural rubbers may be mentioned, and (meth) acrylic resins are particularly preferred.

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, it is preferable because deterioration in both printing durability due to abrasion and printing durability due to ink receptivity is suppressed.

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.
The monovalent organic group is preferably an alkyl group having a carbon number of 1 to 6, and is methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group And n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, cyclopentyl and cyclohexyl.
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 (wherein, R ^A1 to R ^A3 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl R ^1A and R ^2A or R ^3A may combine with each other to form a ring, n represents an integer of 1 to 10, and X represents a dicyclopentan. Represents a dienyl residue)) Rukoto can.

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 per gram of the binder polymer from the viewpoint of good sensitivity and good storage stability. 1 mmol to 10.0 mmol, more preferably 1.0 mmol to 7.0 mmol, particularly preferably 2.0 mmol to 5.5 mmol.

Specific examples 1 to 11 of the binder polymer for on-press development are shown below, but the present disclosure 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 above-mentioned repeating unit. The numerical value added to the repeating unit of the side chain indicates the number of repetition of the above repeating site. Also, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

The binder polymer preferably has a weight average molecular weight (Mw) of 2,000 or more, more preferably 5,000 or more, and 10,000 to 300,000 as the polystyrene conversion value by GPC method. It is further preferred that

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.

The binder polymer may be present in the image recording layer as a polymer functioning as a binder for each component or may be present in the form of particles. When present in the form of particles, the average primary particle size is preferably 10 nm to 1,000 nm, more preferably 20 nm to 300 nm, still more preferably 30 nm to 120 nm.

In the image recording layer used in the present disclosure, one binder polymer may be used alone, or two or more binder polymers may be used in combination.
The binder polymer can be contained in any amount in the image recording layer. The content of the binder polymer can be appropriately selected depending on the application of the image recording layer and the like, but is preferably 1% by mass to 90% by mass, and more preferably 5% by mass to 80% by mass with respect to the total mass of the image recording layer.

[Electron donated polymerization initiator]
The image recording layer used in the present disclosure may contain an electron donated polymerization initiator. In addition, the compound applicable to the above-mentioned specific compound shall not be contained in an electron donor type polymerization initiator.
The electron donating polymerization initiator contributes to the improvement of printing durability in a lithographic printing plate. As an electron donor type polymerization initiator, 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 these electron donating polymerization initiators, the image recording layer preferably contains a borate compound. As the borate compound, a tetraaryl borate compound or a monoalkyl triaryl borate compound is preferable, and from the viewpoint of the stability of the compound, a tetraaryl borate compound is more preferable, and a tetraaryl borate compound having one or more aryl groups having an electron attractive group. Particularly preferred are aryl borate compounds.
As the electron withdrawing group, a group having a positive Hammett's σ value is preferable, and a group having a Hammett's σ value of 0 to 1.2 is more preferable. For Hammett's σ values (σp and σm values), see Hansch, C., et al. Leo, A .; Taft, R .; W. Chem. Rev. 1991, 91, 165-195.
As an electron withdrawing group, a halogen atom, a trifluoromethyl group or a cyano group is preferable, and a fluorine atom, a chlorine atom, a trifluoromethyl group or a cyano group 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 following compounds. 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 electron donating polymerization initiator may be added alone or in combination of two or more.
The content of the electron donating polymerization initiator is preferably 0.01% by mass to 30% by mass, more preferably 0.05% by mass to 25% by mass, based on the total mass of the image recording layer, and 0.1% by mass It is more preferable that the content be up to 20% by mass.

[Chain transfer agent]
The image recording layer used in the present disclosure may contain a chain transfer agent. The chain transfer agent contributes to the improvement of printing durability in a lithographic printing plate.
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.

Specific examples of the chain transfer agent include the following compounds.

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% by mass to 50% by mass, more preferably 0.05% by mass to 40% by mass, and still more preferably 0.1% by mass to 30% by mass with respect to the total mass of the image recording layer. % Is more preferred.

[Low molecular weight hydrophilic compound]
The image recording layer may contain a low molecular weight hydrophilic compound in order to improve the on-press developability while suppressing the deterioration of the printing durability. 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 preferably contains 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 hardly has a surfactant activity, and dampening water penetrates the exposed part (image part) of the image recording layer to reduce the hydrophobicity and the film strength of the image part. And the ink receptivity and the printing durability of the image recording layer can be well maintained.

The content of the low molecular weight hydrophilic compound is preferably 0.5% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and more preferably 2% by mass to 10% by mass with respect to the total mass of the image recording layer. Is more preferred. In this range, good on-press developability and press life can be obtained.
The low molecular weight hydrophilic compounds may be used alone or in combination of two or more.

[Sepetic agent]
The image recording layer may contain a sensitizing agent such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer in order to improve the receptivity. In particular, when an inorganic stratiform compound is contained in the protective layer, these compounds function as a surface coating agent for the inorganic stratiform compound and can suppress the decrease in the receptivity during printing by the inorganic stratiform compound.
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 mol% to 80 mol% of a (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 salt-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 measurement 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- (ethyldimethylammonio) 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 60000)
(5) 2- (trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60, Mw 70000)
(6) 2- (Butyldimethylammonio) ethyl methacrylate = 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-methacryloyloxypropyl methacrylate copolymer (molar ratio 15/80/5, Mw 65,000)

The content of the sensitizing agent is preferably 0.01% by mass to 30.0% by mass, and more preferably 0.1% by mass to 15.0% by mass, with respect to the total mass of the image recording layer. % To 10% by mass is more preferable.

[Other ingredients]
The image recording layer may contain, as other components, surfactants, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic particles, inorganic layered compounds, and the like. Specifically, the description in paragraphs [0114] to [0159] of JP-A-2008-284817 can be referred to.

[Formation of image recording layer]
The image recording layer in the lithographic printing plate precursor according to the present disclosure is, for example, dispersed or dissolved in a known solvent and applied as described in paragraphs 0142 to 0143 of JP-A-2008-195018. The solution can be prepared, coated on a support by a known method such as bar coating, and dried. The coating amount (solid content) of the image recording layer after coating and drying varies depending on the application, but generally 0.3 g / m ² to 3.0 g / m ² is preferable. Within this range, good sensitivity and good film properties of the image recording layer can be obtained.
In the present disclosure, the solid content is the total amount of components excluding volatile components such as a solvent in the composition.

<Subbing layer>
The lithographic printing plate precursor according to the present disclosure 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 the heat generated by the exposure from being diffused to the support to reduce the sensitivity.

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 pair charge with the polar substituent and a compound having an ethylenically unsaturated bond, or Other 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 bonding group in the polymer used for the undercoat layer is preferably 0.1 mmol to 10.0 mmol, more preferably 0.2 mmol 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 mg / m ² to 100 mg / m ^{2, and} more preferably 1 mg / m ² to 30 mg / m ² .

<Protective layer>
The lithographic printing plate precursor according to the present disclosure preferably has a protective layer (sometimes referred to as 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 a mica compound, for example, the formula: A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂ [wherein, A is any of K, Na and Ca, and B and C are It is any of Fe (II), Fe (III), Mn, Al, Mg and V, and D is Si or Al. 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 above-mentioned mica compounds, fluorine-based swellable mica is particularly useful. That is, the swellable synthetic mica has a laminated structure composed of unit crystal lattice layers having a thickness of about 10 Å to 15 Å (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 μm to 20 μm, more preferably 0.5 μm to 10 μm, and particularly preferably 1 μm 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 nm to 50 nm, and the surface size (long diameter) is about 1 μm to 20 μm.

The content of the inorganic stratiform compound is preferably 1% by mass to 60% by mass, and more preferably 3% by mass 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. Further, the oil-receptive agent described in the image recording layer may be contained in the protective layer.

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

<Support>
The support of the lithographic printing plate precursor according to the present disclosure can be appropriately selected from known supports for lithographic printing plate precursors. As the support, a support having a hydrophilic surface is preferred. Moreover, as a support body, the aluminum plate surface-roughened by a well-known method and anodized is preferable.
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 μm 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 making lithographic printing plate)
A lithographic printing plate can be produced by imagewise exposing the lithographic printing plate precursor according to the present disclosure and performing development processing.
The plate-making method of a lithographic printing plate according to the present disclosure comprises: exposing the lithographic printing plate precursor according to the present disclosure image-wise to form an exposed area and an unexposed area; and at least printing ink and dampening water An on-machine development step of supplying one to remove the unexposed area is included in this order.
Hereinafter, preferred embodiments of the respective steps of the lithographic printing plate making method according to the present disclosure and the lithographic printing method according to the present disclosure will be described in order. The lithographic printing plate precursor according to the present disclosure can also be developed by a developer.

<Exposure process>
The plate making method of a lithographic printing plate according to the present disclosure preferably includes an exposing step of imagewise exposing the lithographic printing plate precursor according to the present disclosure to form an exposed area and an unexposed area. The lithographic printing plate precursor according to the present disclosure is preferably imagewise exposed by laser exposure through a transparent original having a line image, halftone dot image or the like or by laser light scanning with digital data.
The wavelength of the light source is preferably 750 nm to 1,400 nm. As a light source of 750 nm to 1,400 nm, a solid state laser and a semiconductor laser emitting infrared rays are preferable. For an infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the amount of irradiation energy is 10 mJ / cm ² to 300 mJ / cm ^2. preferable. Moreover, in order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure mechanism may be any of an inner drum system, an outer drum system, and a flat bed system.
Image exposure can be performed by a conventional method using a platesetter or the like. In the case of on-press development, the lithographic printing plate precursor may be mounted on a printing press and then imagewise exposed on the printing press.

<On-press development process>
The method for making a lithographic printing plate according to the present disclosure preferably includes an on-press development step of supplying at least one of printing ink and dampening water to remove the unexposed area.
In addition, the method for making a lithographic printing plate according to the present disclosure may be carried out by a method of developing with a developer (developer processing method).
The on-press development method will be described below.

[On-press development method]
In the on-press development method, an imagewise exposed lithographic printing plate precursor is supplied with an oil-based ink and an aqueous component on a printing press, and the image recording layer in the non-image area is removed to prepare a lithographic printing plate Is preferred.
That is, the lithographic printing plate precursor is imagewise exposed and then mounted as it is without any development processing, or the lithographic printing plate precursor is mounted on a printing machine and then imagewise exposed on the printing press and then When an oil-based ink and an aqueous component are supplied and printed, an uncured image recording layer is formed by the supplied oil ink and / or the aqueous component in the non-image area at an early stage of printing. It dissolves or disperses away, and the hydrophilic surface is exposed in that part. On the other hand, in the exposed portion, the image recording layer cured by the exposure forms an oil-based ink receiving portion having a lipophilic surface. An oil-based ink or an aqueous component may be supplied first to the printing plate, but the oil-based ink is first supplied in that the aqueous component is prevented from being contaminated by the removed components of the image recording layer. Is preferred. Thus, the lithographic printing plate precursor is developed on the press on a printing press and used as it is for printing a large number of sheets. As an oil-based ink and an aqueous component, the printing ink and dampening water for normal lithographic printing are used suitably.

<Printing process>
The planographic printing method according to the present disclosure includes a printing step of supplying a printing ink to the planographic printing plate developed on-press in the above-described on-press development step to print a recording medium.
The printing ink is not particularly limited, and various known inks can be used as desired. Moreover, as printing ink, oil-based ink is mentioned preferably. Among oil-based inks, UV-curable inks are preferably mentioned.
In the printing step, dampening water may be supplied as necessary.
The printing process may be performed continuously to the on-press development process without stopping the printing machine.
There is no restriction | limiting in particular as a recording medium, If desired, a well-known recording medium can be used.

In the plate-making method of a lithographic printing plate from a lithographic printing plate precursor according to the present disclosure, and in the lithographic printing method according to the present disclosure, as required, before exposure, during exposure, and between exposure and development The entire surface of the plate precursor may be heated. Such heating accelerates the image forming reaction in the image recording layer, and may provide advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity. Heating before development is preferably performed under mild conditions of 150 ° C. or less. According to the above aspect, it is possible to prevent problems such as curing of the non-image area. It is preferable to use very strong conditions for heating after development, and a range of 100 ° C. to 500 ° C. is preferable. Within the above range, a sufficient image enhancing action can be obtained, and problems such as deterioration of the support and thermal decomposition of the image portion can be suppressed.

(Coloring composition)
The color forming composition according to the present disclosure includes a compound (specific compound) having a cation portion having a radical reactive group and an anion portion containing a boron atom, and an acid color agent.
The specific compound and the acid color former in the color forming composition have the same meaning as the specific compound and the acid color former in the image recording layer of the above-mentioned lithographic printing plate precursor, and the preferred embodiments are also the same.
In addition, the color forming composition preferably contains an infrared absorber, and more preferably contains an infrared absorber which is decomposed by an acid to form a color.
The infrared absorber in the color forming composition has the same meaning as the infrared absorber in the image recording layer of the above-mentioned lithographic printing plate precursor, and the preferred embodiments are also the same.
Furthermore, the color forming composition according to the present disclosure is a group consisting of a radically polymerizable compound, a radical polymerization initiator, a polymer particle, a binder polymer, a chain transfer agent, a low molecular weight hydrophilic compound, a sensitizing agent, and a known solvent. And at least one selected from the group consisting of Preferred embodiments of these compounds are the same as the preferred embodiments of the respective compounds in the above-mentioned lithographic printing plate precursor.

The content of each component contained in the color forming composition according to the present disclosure corresponds to the amount obtained by replacing the content of each component contained in the image recording layer of the above-mentioned lithographic printing plate precursor with the solid content in the color forming composition. .

A lithographic printing plate precursor can be obtained by using the color forming composition according to the present disclosure.
The photosensitive resin composition according to the present disclosure is also suitably used in the fields of image forming materials, 3D modeling and the like.

(Curable composition)
The curable composition which concerns on this indication contains the compound (specific compound) which has a cation part which has a radically reactive group, and the anion part containing a boron atom, an infrared rays absorber, and a radically polymerizable compound.
The specific compound, the infrared absorber and the radically polymerizable compound in the curable composition are the same as the specific compound, the infrared absorber and the radically polymerizable compound in the image recording layer of the above-mentioned planographic printing plate precursor, and the preferred embodiments are also the same. is there.
In addition, the curable composition preferably further contains a radical polymerization initiator.
The radical polymerization initiator in the curable composition has the same meaning as the infrared absorber in the image recording layer of the above-mentioned lithographic printing plate precursor, and the preferred embodiments are also the same.
Furthermore, the curable composition according to the present disclosure comprises at least at least one selected from the group consisting of polymer particles, binder polymers, acid color formers, chain transfer agents, low molecular weight hydrophilic compounds, oil sensitizers, and known solvents. One type may be further contained. Preferred embodiments of these compounds are the same as the preferred embodiments of the respective compounds in the above-mentioned lithographic printing plate precursor.

The content of each component contained in the curable composition according to the present disclosure is the amount obtained by replacing the content of each component contained in the image recording layer of the above-mentioned lithographic printing plate precursor with the solid content in the curable composition. Equivalent to.

A lithographic printing plate precursor can be obtained by using the curable composition according to the present disclosure.
The curable composition according to the present disclosure is also suitably used in the fields of image forming materials, 3D modeling and the like.

(Image-forming material)
The image forming material according to the present disclosure includes the curable composition according to the present disclosure or the color forming composition according to the present disclosure.
The image forming material according to the present disclosure preferably contains the curable composition according to the present disclosure or the color forming composition according to the present disclosure as an image recording layer.
In addition, the image forming material according to the present disclosure preferably includes at least one of a subbing layer, a protective layer, and a support.
The undercoat layer, the protective layer and the support in the image forming material according to the present disclosure are the same as the undercoat layer, the protective layer and the support in the lithographic printing plate precursor according to the present disclosure, and preferred embodiments are also the same. .

Hereinafter, the present disclosure will be described in detail by way of examples, but the present disclosure is not limited thereto. In the examples, “%” and “parts” mean “% by mass” and “parts by mass” unless otherwise noted. In the polymer compound, the molecular weight is a weight average molecular weight (Mw), and the ratio of the constituent repeating units is a molar percentage, except as specially specified. Moreover, a weight average molecular weight (Mw) is a value measured as a polystyrene conversion value by gel permeation chromatography (GPC) method.

(Synthesis of Compound A-1)
(3-Acrylamidopropyl) trimethyl ammonium chloride (74 to 76% by mass aqueous solution) (5.5 parts by mass) is added to a mixed solution of sodium tetraphenylborate (7.2 parts by mass) and methanol (150 parts by mass) did.
The reaction solution was stirred at room temperature for 30 minutes, and then the precipitated crystals were collected by filtration and washed with water to obtain 9.5 parts by mass of a target compound A-1.
¹ H-NMR (400 MHz, DMSO-d6) δ 1.9 (m, 2 H), 3.0 (s, 9 H), 3.2 (m, 2 H), 3.3 (m, 2 H), 5.6 (D, 1 H), 6.1 (dd, 1 H), 6.2 (d, 1 H), 6.7 (m, 4 H), 6.9 (m, 8 H), 7.2 (m, 8 H) , 8.1 (s, 1 H)
Compounds A-2 to A-10 were synthesized in the same manner as for compound A-1.

(Synthesis of Comparative Compound 1)
Choline chloride (2.8 parts by mass) was added to a mixed solution of sodium tetraphenylborate (7.2 parts by mass) and methanol (150 parts by mass).
The reaction solution was stirred at room temperature for 30 minutes, and then the precipitated crystals were collected by filtration and washed with water to obtain 8.5 parts by mass of Comparative Compound 1.
¹ H-NMR (400 MHz, DMSO-d6) δ 2.5 (m, 2 H), 3.1 (s, 9 H), 5.2 (t, 2 H), 6.7 (m, 4 H), 6.9 (M, 8 H), 7.2 (m, 8 H)

(Preparation of lithographic printing plate precursor)
<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. Thereafter, the surface of the aluminum plate was grained using three bundle-planted nylon brushes having a diameter of 0.3 mm and a pumice-water suspension (specific gravity: 1.1 g / cm ³ ) having a median diameter of 25 μm, and thoroughly washed with water. 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 ms for the current value to reach a peak and a duty ratio of 1: 1. 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 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.
Hereinafter, a lithographic printing plate precursor was produced using the support C described above.

<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 parts Hydroxyethyliminodiacetic acid: 0.10 parts Water: 61.4 parts

In the following structures, subscripts in parentheses indicating polyethylene glycol chains represent the number of repetitions.

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 weight average molecular weight (Mw) made into the polyethylene glycol conversion value by gel permeation chromatography (GPC) method was 200,000.

Droplet 1
Aqueous solution of Monomer M-1: 132.4 parts Aqueous solution of Monomer M-2: 376.9 parts Monomer M-3 (below): 184.3 parts Blemmer PME 4000 (manufactured by NOF Corporation): 15 .3 parts VA-046B (Wako Pure Chemical Industries, Ltd.): 3.9 parts Distilled water: 717.4 parts

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>
In each of the Examples and Comparative Examples, an image recording layer coating solution (1) having the following composition was bar-coated on the undercoat layer, dried in an oven at 70 ° C. for 60 seconds, and dried at a coating amount of 0.6 g / m ² A recording layer was formed to prepare a lithographic printing plate precursor C.
The following image recording layer coating solution corresponds to the curable composition according to the present disclosure and the color forming composition according to the present disclosure.

[Image recording layer coating solution (1)]
Infrared absorber (D-4) (compound of the following structure): 0.018 parts Radical polymerization initiator I-5-j-1 (compound of the following structure): 0.160 parts Identification described in Table 1 Compound: Amount described in Table 1-Polymer particle water dispersion (1) (22 mass%): 10.0 parts-Radically polymerizable compound SR-399 (made by Sartmar): 1.50 parts-Acid color former: 2′-anilino-6 ′-(N-ethyl-N-isopentylamino) -3′-methylspiro [phthalide-3,9′-xanthene] (S-205, manufactured by Fukui Yamada Chemical Industry Co., Ltd.): 0 .080 parts mercapto-3-triazole: 0.2 parts Byk 336 (manufactured by Byk Chemie): 0.4 parts Klucel M (manufactured by Hercules): 4.8 parts ELVACITE 4026 (manufactured by Ineos Acrylics) : 2 .5 parts n-propanol: 55.0 parts 2-butanone 17.0 parts

The radical polymerization initiator I-5-j-1 is a compound having the following anion part I-5 and the following cation part j-1. In the following structure, Me represents a methyl group, and Et represents an ethyl group.

The details of the abbreviations described in the composition of the image recording layer coating solution (1) are as follows.
· 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-pig)

The preparation method of the polymer particle water dispersion (1) used for the said image recording layer coating liquid (1) 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) The mixture was heated to a temperature of 70 ° C. by adding 10 parts of the number: 50), 200 parts of distilled water and 200 parts of n-propanol. Next, a mixture of 10 parts of previously mixed styrene (St), 80 parts of acrylonitrile (AN) and 0.8 parts 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 parts of 2,2'-azobisisobutyronitrile was added, and the internal temperature was raised to 80.degree. Subsequently, 0.5 part 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)
<Evaluation of chromogenicity>
The lithographic printing plate precursor according to each of the Examples and Comparative Examples is 11.7 W output, 250 rpm outer surface drum rotation speed, resolution 2,400 dpi (dot per inch, 1 inch = 25) using a water-cooled 40 W infrared semiconductor laser mounted Trendsetter 3244 VX manufactured by Creo. It exposed on the conditions of .4 mm. The exposure was performed under the environment of 25 ° C. and 50% relative humidity (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 coloring property 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 2 shows the values of ΔL ^* . The larger the value of ΔL ^*, the better the color developability, and the better the plate detectability of the lithographic printing plate by color development. Moreover, it can be said that the larger the color forming value, the better the color forming property of the color forming composition.

<Evaluation of UV printing durability>
The lithographic printing plate precursor prepared as described above was exposed (magnification energy: 110 mJ / cm ²⁾ at an output of 27 W, an external drum rotation speed of 450 rpm, and a resolution of 2,400 dpi using Magnus 800 Quantum manufactured by Kodak equipped with an infrared semiconductor laser. Equivalent). The exposed image included a solid image and an AM screen (Amplitude Modulation Screen) chart of 3% halftone dots.

The obtained exposed lithographic printing plate precursor was mounted on a cylinder of a Kiku-size (939 mm × 636 mm) Heidelberg printing machine SX-74 without development processing. A dampening water circulation tank with a capacity of 100 L containing a non-woven fabric filter and a temperature control device was connected to this printing press. Dampening water S-Z1 (Fuji Film Co., Ltd. product) 80L of dampening water of 2.0% is charged into a circulation device, and T & K UV OFS K-HS black ink GE-M (trade Co., Ltd. made by T & K TOKA) as a printing ink The dampening water and the ink were supplied by a standard automatic printing start method, and then printing was performed on Tokiwa Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
As the number of printed sheets increased, the image area was gradually worn away, and the ink density on the printed matter decreased. The number of printed copies when the value obtained by measuring the halftone dot area rate of 3% halftone screen of AM screen with a Gretag densitometer (manufactured by GretagMacbeth) is 1% lower than the measured value of the 500th printed sheet The UV printing resistance was evaluated. Specifically, the relative printing durability was evaluated by setting the printing resistance to 100 when the number of printed sheets is 50,000 according to the following equation. The higher the value, the better the UV printing resistance. Moreover, it can be said that the larger the printing durability value, the better the chemical resistance after curing of the curable composition. The evaluation results are shown in Table 2.
Relative printing durability = (number of copies of target lithographic printing plate precursor) / 50,000 × 100

<Evaluation of on-press developability>
Under the same conditions as the above-mentioned UV printing resistance, printing was started without developing the exposed lithographic printing plate precursor.
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.

From the results described in Table 2, according to the lithographic printing plate precursor according to the present disclosure, a lithographic printing plate precursor from which a lithographic printing plate having excellent printing durability can be obtained even when using an ultraviolet-curable ink in printing It is understood that it can be obtained.
In addition, the planographic printing plate precursors according to Examples 1 to 5 were also excellent in color development as compared with the planographic printing plate precursors according to Comparative Example 1 and Comparative Example 2.

The disclosure of Japanese Patent Application No. 2017-137247, filed July 13, 2017, is incorporated herein by reference in its entirety.
All documents, patent applications and technical standards described herein are the same as if each individual document, patent application and technical standard was specifically and individually indicated to be incorporated by reference. Incorporated herein by reference.

Claims

Having an image recording layer on a support,
A lithographic printing plate precursor as described above, wherein the image recording layer comprises a compound having a cation moiety having a radical reactive group and an anion moiety containing a boron atom, an infrared absorber, and a radical polymerizable compound.
The lithographic printing plate precursor as claimed in claim 1, wherein the radically reactive group is a radical polymerizable group or a mercapto group.
The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the cationic part has a structure represented by the following formula 1.

In Formula 1, X represents a group represented by the following Formula 2, a pyridinium group, or an imidazolium group, and Y represents a structure including a radical reactive group.

In Formula 2, R 5 to R 7 each independently represent an alkyl group or an aryl group, and a plurality of R 5 to R 7 may combine with each other to form a ring; It represents a binding site to Y.
The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the molecular weight of the cationic part is 59 to 1,000.
The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the anion moiety is a structure represented by the following formula 3.

In Formula 3, R 1 to R 4 each independently represent an alkyl group or an aryl group.
The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein the anion moiety is a tetraphenyl borate anion.
The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the image recording layer further comprises a radical polymerization initiator.
The lithographic printing plate precursor as claimed in claim 7, wherein the radical polymerization initiator contains at least one of an iodonium salt and a sulfonium salt.
The lithographic printing plate precursor as claimed in any one of claims 1 to 8, wherein the image recording layer further comprises an acid color former.
The lithographic printing plate precursor as claimed in any one of claims 1 to 9, wherein the image recording layer further comprises polymer particles.
The lithographic printing plate precursor as claimed in any one of claims 1 to 10, wherein the image recording layer further comprises a binder polymer.
An exposure step of imagewise exposing the lithographic printing plate precursor according to any one of claims 1 to 11 to form an exposed portion and an unexposed portion;
A method for making a lithographic printing plate, comprising an on-press development step of supplying at least one of a printing ink and a dampening solution to remove the unexposed area.
A compound having a cation moiety having a radical reactive group and an anion moiety containing a boron atom,
A coloring composition containing an acid color former.
A compound having a cation moiety having a radical reactive group and an anion moiety containing a boron atom,
Infrared absorber, and
A curable composition containing a radically polymerizable compound.
An image forming material comprising the color forming composition according to claim 13 or the curable composition according to claim 14.