阅读说明：本技术 平版印刷版原版、平版印刷版原版制作用树脂组合物及平版印刷版的制作方法 (Lithographic printing plate precursor, resin composition for producing lithographic printing plate precursor, and method for producing lithographic printing plate ) 是由 平野修史 榎本和朗 野越启介 于 2018-05-08 设计创作，主要内容包括：本发明提供一种在亲水性支撑体上具有图像记录层,且上述图像记录层包括具有包含溶解度参数为20MPa<Sup>1/2</Sup>以上的单体的构成单元的聚合物、红外线吸收剂及聚合物粒子的平版印刷版原版；包含上述聚合物、红外线吸收剂及聚合物粒子的平版印刷版原版制作用树脂组合物；以及使用上述平版印刷版原版的平版印刷版的制作方法。(The invention provides a hydrophilic support having an image recording layer thereon, wherein the image recording layer has a solubility parameter of 20MPa 1/2 A lithographic printing plate precursor comprising a polymer of the above-mentioned monomer-constituting unit, an infrared absorber and polymer particles; a resin composition for producing a lithographic printing plate precursor, which contains the above polymer, an infrared absorber and polymer particles; and a method for producing a lithographic printing plate using the lithographic printing plate precursor.)

1. A lithographic printing plate precursor, wherein,

an image recording layer is provided on a hydrophilic support,

the image recording layer includes:

has a solubility parameter of 20MPa^1/2A polymer of a constituent unit of the above monomer,

An infrared absorber, and

polymer particles.

2. The lithographic printing plate precursor according to claim 1,

the solubility parameter of the monomer is 25MPa^1/2The above.

3. The lithographic printing plate precursor according to claim 1 or 2,

the solubility parameter of the monomer is 30MPa^1/2The above.

4. The lithographic printing plate precursor according to any one of claims 1 to 3,

the polymer also has a constituent unit containing a group represented by the following formula Z,

-Q-W-Y formula Z

In formula Z, Q represents a divalent linking group, W represents a divalent group having a hydrophilic structure or a divalent group having a hydrophobic structure, and Y represents a monovalent group having a hydrophilic structure or a monovalent group having a hydrophobic structure, where either W or Y has a hydrophilic structure.

5. The lithographic printing plate precursor according to any one of claims 1 to 4,

the polymer is an addition polymerization type resin.

6. The lithographic printing plate precursor according to any one of claims 1 to 5,

the polymer also has a constitutional unit containing a polyalkylene oxide structure.

7. The lithographic printing plate precursor according to any one of claims 1 to 6,

the polymer has at least 1 structure selected from the group consisting of a urethane bond, a urea bond, a hydroxyl group, an amide group, a cyano group, a sulfonamide group, an amino group, and a sulfonimide group.

8. The lithographic printing plate precursor according to any one of claims 1 to 7,

the polymer has at least 1 structure selected from the group consisting of a urethane bond, a urea bond, a hydroxyl group, an amide group, and a cyano group.

9. The lithographic printing plate precursor according to any one of claims 1 to 8,

the polymer has at least 1 structure selected from the group consisting of a urethane bond and a urea bond.

10. The lithographic printing plate precursor according to any one of claims 1 to 9,

the polymer also has a constitutional unit containing an ethylenically unsaturated group.

11. The lithographic printing plate precursor according to any one of claims 1 to 10,

the image recording layer further includes a polymerization initiator and a polymerizable compound.

12. The lithographic printing plate precursor according to any one of claims 1 to 11,

a protective layer is also provided on the image recording layer.

13. The lithographic printing plate precursor according to claim 12,

the protective layer includes an inorganic layered compound.

14. The lithographic printing plate precursor according to any one of claims 1 to 13, which is an on-press development lithographic printing plate precursor.

15. A resin composition for lithographic printing plate precursor production, which comprises a resin having a solubility parameter of 20MPa^1/2A polymer of the above-mentioned monomer constituent unit, an infrared absorber, and polymer particles.

16. A method of making a lithographic printing plate comprising:

a step of imagewise exposing the lithographic printing plate precursor according to any one of claims 1 to 14 to form exposed portions and unexposed portions; and

and a step of supplying at least one of printing ink and dampening solution to remove the unexposed portion.

17. A method of making a lithographic printing plate comprising: a step of imagewise exposing the lithographic printing plate precursor according to any one of claims 1 to 13 to form exposed portions and unexposed portions; and

and removing the unexposed portions of the image recording layer with a developing solution having a pH of 2 to 11.

Technical Field

The present invention relates to a lithographic printing plate precursor, a resin composition for producing a lithographic printing plate precursor, and a method for producing a lithographic printing plate.

Background

In general, a lithographic printing plate is composed of an oleophilic image portion that receives ink during printing and a hydrophilic non-image portion that receives fountain solution. The lithographic printing is a method of printing by using the property that water and oil-based ink repel each other, using a lipophilic image portion of a lithographic printing plate as an ink-receiving portion and a hydrophilic non-image portion as a fountain solution-receiving portion (non-ink-receiving portion), causing a difference in ink adhesion on the surface of the lithographic printing plate, allowing ink to adhere only to the image portion, and then transferring the ink to a printing object such as paper.

In order to produce such a lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. In general, a lithographic printing plate is obtained by plate making as follows: after exposure of a lithographic printing plate precursor to an original image such as a high contrast film, a portion of the image recording layer to be an image portion is left, and unnecessary image recording layers other than the image recording layer are removed by dissolving in an alkaline developer or an organic solvent, whereby a non-image portion is formed by exposing the surface of the hydrophilic support.

Further, since the global environment is being increasingly concerned, environmental problems associated with waste liquid accompanying wet treatment such as development treatment become apparent.

The environmental problems are directed to simplification and no treatment of development and plate making. As one of the simple manufacturing methods, a method called "on-press development" is being performed. Namely, the following method is used: after exposure of the lithographic printing plate precursor, the lithographic printing plate precursor is directly mounted on a printing press without conventional development, and unnecessary portions of the image recording layer are removed at an initial stage of a normal printing process.

As conventional lithographic printing plate precursors, for example, the lithographic printing plate precursors described in patent document 1 and patent document 2 can be cited.

Jp 2012-048152 a discloses a lithographic printing plate precursor comprising a support having a hydrophilic surface, and a photosensitive layer provided on the support, wherein the photosensitive layer contains (component f) an ionic polymerization initiator, (component a) a pigment, (component b) a pigment dispersant having a heterocyclic ring, and (component c) a pigment dispersant having a polar group.

Jp 2007-316598 a describes a lithographic printing plate precursor characterized in that after image-exposing a lithographic printing plate precursor having a photosensitive layer on a support with a laser beam of 350 to 450nm, the plate surface is rubbed with a rubbing member in the presence of a developer having a pH of 2 to 10 by an automatic processor equipped with a rubbing member to remove the photosensitive layer of a non-exposed portion, wherein the photosensitive layer comprises a photosensitive resin composition containing (a) a sensitizing dye that absorbs light of 350 to 450nm, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a binder polymer, and the binder polymer (D) is an acrylic resin having a hydrophilic group and a crosslinkable group and having an acid value of 0.3meq/g or less.

Disclosure of Invention

Technical problem to be solved by the invention

Among lithographic printing plates, there is a demand for lithographic printing plates having excellent printable number of plates (hereinafter, also referred to as "printing durability").

In particular, in recent years, as an ink for printing, an ink that is cured by irradiation of Ultraviolet (UV) (also referred to as "ultraviolet-curable ink") may be used.

The ultraviolet curable ink has the following advantages: because of being dried instantly, the production rate is high; in general, since the content of the solvent is low or no solvent is present, environmental pollution is easily reduced; since an image can be formed without performing heat-based drying or by performing heat-based drying in a short time, the application range of a printing object and the like is wide; and the like.

Therefore, it is considered that a lithographic printing plate which can provide a lithographic printing plate excellent in printing durability when an ultraviolet curable ink is used is industrially very useful.

As a result of intensive studies, the present inventors have found that, in the lithographic printing plate precursor described in japanese patent application laid-open nos. 2012 and 048152 and 2007 and 316598, there is a problem that the obtained lithographic printing plate has insufficient printing durability particularly when an ultraviolet-curable ink is used as the ink.

An object of embodiments of the present invention is to provide a lithographic printing plate precursor that can provide a lithographic printing plate having excellent printing durability even when an ultraviolet curable ink is used.

Another object of another embodiment of the present invention is to provide a resin composition for producing a lithographic printing plate precursor, which can provide a lithographic printing plate having excellent printing durability even when an ultraviolet curable ink is used.

Another object of the present invention is to provide a method for manufacturing a lithographic printing plate having excellent printing durability even when an ultraviolet curable ink is used.

Means for solving the technical problem

The means for solving the above problems include the following means.

< 1 > A lithographic printing plate precursor, wherein an image-recording layer is provided on a hydrophilic support, said image-recording layer comprising a polymer having a solubility parameter of 20MPa^1/2A polymer of the above-mentioned monomer constituent unit, an infrared absorber, and polymer particles.

< 2 > the lithographic printing plate according to < 1 > aboveA master, wherein the solubility parameter of the monomer is 25MPa^1/2The above.

< 3 > the lithographic printing plate precursor according to the above < 1 > or < 2 >, wherein the solubility parameter of the above monomer is 30MPa^1/2The above.

< 4 > the lithographic printing plate precursor according to any of the above < 1 > to < 3 >, wherein the above polymer further has a constituent unit containing a group represented by the following formula Z.

-Q-W-Y formula Z

In formula Z, Q represents a divalent linking group, W represents a divalent group having a hydrophilic structure or a divalent group having a hydrophobic structure, and Y represents a monovalent group having a hydrophilic structure or a monovalent group having a hydrophobic structure, where either W or Y has a hydrophilic structure.

< 5 > the lithographic printing plate precursor according to any of the above < 1 > to < 4 >, wherein the above polymer is an addition polymerization type resin.

< 6 > the lithographic printing plate precursor according to any of the above < 1 > to < 5 >, wherein the above polymer further has a constituent unit containing a polyalkylene oxide structure.

< 7 > the lithographic printing plate precursor according to any of the above < 1 > to < 6 >, wherein the polymer has at least 1 structure selected from the group consisting of a urethane bond, a urea bond, a hydroxyl group, an amide group, a cyano group, a sulfonamide group, an amino group, and a sulfonylimide group.

< 8 > the lithographic printing plate precursor according to any of the above < 1 > to < 7 >, wherein the above polymer has at least 1 structure selected from the group consisting of a urethane bond, a urea bond, a hydroxyl group, an amide group and a cyano group.

< 9 > the lithographic printing plate precursor according to any of the above < 1 > to < 8 >, wherein the above polymer has at least 1 structure selected from the group consisting of a urethane bond and a urea bond.

< 10 > the lithographic printing plate precursor according to any of the above < 1 > to < 9 >, wherein the above polymer further has a constitutional unit containing an ethylenically unsaturated group.

< 11 > the lithographic printing plate precursor according to any of the above < 1 > to < 10 >, wherein the image recording layer further comprises a polymerization initiator and a polymerizable compound.

< 12 > the lithographic printing plate precursor according to any of the above < 1 > to < 11 >, wherein a protective layer is further provided on the image-recording layer.

< 13 > the lithographic printing plate precursor according to the above < 12 >, wherein the above protective layer comprises an inorganic layered compound.

< 14 > the lithographic printing plate precursor according to any one of the above < 1 > to < 13 > which is a lithographic printing plate precursor for on-press development.

< 15 > a resin composition for lithographic printing plate precursor production comprising a resin having a solubility parameter of 20MPa^1/2A polymer of the above-mentioned monomer constituent unit, an infrared absorber, and polymer particles.

< 16 > a method for producing a lithographic printing plate, comprising: a step of imagewise exposing the lithographic printing plate precursor described in any of the above-mentioned < 1 > to < 14 > to form exposed portions and unexposed portions; and a step of supplying at least one of printing ink and dampening solution to remove the unexposed portion.

< 17 > a method for producing a lithographic printing plate, comprising: a step of imagewise exposing the lithographic printing plate precursor described in any of the above-mentioned < 1 > to < 13 > to form exposed portions and unexposed portions; and removing the unexposed portions of the image recording layer with a developing solution having a pH of 2 to 11.

Effects of the invention

According to the embodiment of the present invention, a lithographic printing plate precursor capable of providing a lithographic printing plate having excellent printing durability even when an ultraviolet curable ink is used can be provided.

Further, according to another embodiment of the present invention, there can be provided a resin composition for producing a lithographic printing plate precursor, which can provide a lithographic printing plate having excellent printing durability even when an ultraviolet curable ink is used.

According to still another embodiment of the present invention, a method for manufacturing a lithographic printing plate having excellent printing durability even when an ultraviolet curable ink is used can be provided.

Detailed Description

Hereinafter, the present disclosure will be described in detail. The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.

In the present specification, "to" indicating a numerical range is used in a meaning including numerical values described before and after the range as a lower limit value and an upper limit value.

In the labeling of the group (atomic group) in the present specification, the label not labeled with substitution and unsubstituted includes not only a group having no substituent but also a group having a substituent. For example, "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 acid" is a term used as a term including both acrylic acid and methacrylic acid, and "(meth) acryloyl group" is a term used as a term including both acryloyl group and methacryloyl group.

The term "step" in the present specification includes not only an independent step but also a step that can achieve the intended purpose of the step even when the step cannot be clearly distinguished from other steps. In the present invention, "mass%" and "weight%" have the same definition, and "parts by mass" and "parts by weight" have the same definition.

In the present invention, a combination of 2 or more preferred embodiments is a more preferred embodiment.

Unless otherwise specified, the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present invention are molecular weights obtained by Gel Permeation Chromatography (GPC) analysis using a column of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (trade names of TOSOH CORPORATION), detected by a solvent THF (tetrahydrofuran) and a differential refractometer, and converted into polystyrene as a standard substance.

In the present specification, the term "lithographic printing plate precursor" includes not only lithographic printing plate precursors but also waste printing plate precursors. The term "lithographic printing plate" includes not only a lithographic printing plate produced by exposing and developing a lithographic printing plate precursor as needed, but also a waste plate. When the plate precursor is discarded, the operations of exposure and development are not necessarily required. The waste plate is a lithographic printing plate precursor to be mounted on an unused plate cylinder when printing a part of a plate surface in monochrome or two-color in, for example, color newspaper printing.

In the present specification, an "+" in the chemical structural formula represents a bonding position with another structure.

The present invention will be described in detail below.

(original plate of lithographic printing plate)

The lithographic printing plate precursor according to the present invention has an image recording layer on a hydrophilic support, wherein the image recording layer has a solubility parameter (hereinafter, also referred to as "SP value") of 20MPa^1/2A polymer of the above-mentioned monomer constituent unit, an infrared absorber, and polymer particles.

The lithographic printing plate precursor according to the present invention can be preferably used as an on-press development lithographic printing plate precursor.

As a result of intensive studies, the present inventors have found that a lithographic printing plate precursor capable of providing a lithographic printing plate having excellent printing durability (hereinafter, also referred to as UV printing durability) even when an ultraviolet curable ink is used can be provided by adopting the above-described structure.

The detailed mechanism by which the above-described effects can be obtained is not clear, but is presumed as follows.

Consider that: by including a solvent having a solubility parameter of 20MPa^1/2The polymer, the infrared absorber, and the polymer particles of the constituent unit of the monomer as described above have a large difference in solubility parameter between the polymer and a solvent, a polymerizable compound, or the like contained in ink used for printing, and thus dissolution of the solvent, the polymerizable compound, or the like is suppressed, and printing durability is improved even when an ultraviolet-curable ink is used. And, it is considered that: since the solubility parameter of the polymer is high and the polarity is high, the interaction force between the polymers, the interaction force between the polymer and the infrared absorber, and the interaction force between the polymer and the polymer particle are improved, and the printing durability is improved even when an ultraviolet curable ink is used.

And, it is considered that: by including a solvent having a solubility parameter of 20MPa^1/2The image-forming layer of the polymer of the constituent unit of the monomer has an appropriate balance of hydrophilicity, and the lithographic printing plate precursor having improved affinity with ink or fountain solution and excellent on-press developability can be easily obtained.

< image recording layer >

The lithographic printing plate precursor of the present invention has an image-recording layer comprising a compound having a solubility parameter of 20MPa^1/2A polymer of the above-mentioned monomer constituent unit, an infrared absorber, and polymer particles.

The image recording layer used in the present invention is preferably a negative image recording layer.

From the viewpoint of printing durability and photosensitivity, the image recording layer in the present invention is preferably either the first or second embodiment described below.

The first mode is as follows: containing a compound having a solubility parameter of 20MPa^1/2A polymer of the above-mentioned monomer constituent unit, an infrared absorber, polymer particles, a polymerization initiator, and a polymerizable compound.

The second mode is as follows: containing a compound having a solubility parameter of 20MPa^1/2The polymer of the constituent unit of the above monomer, the infrared absorber, and the hydrophobic thermoplastic polymer particles.

In the first aspect, the image recording layer used in the present invention preferably further contains a binder polymer from the viewpoint of printing durability, particularly UV printing durability.

In the image recording layer used in the present invention, hydrophobic thermoplastic polymer particles may be contained as the polymer particles in the first aspect from the viewpoint of on-screen developability.

In the lithographic printing plate precursor according to the present invention, it is preferable that the unexposed portion of the image recording layer can be removed by at least one of a fountain solution and a printing ink from the viewpoint of on-press developability.

The details of each component contained in the image recording layer will be described below.

-has a solubility parameter of 20MPa^1/2Polymers of constituent units of the above monomers-

The image recording layer in the lithographic printing plate precursor according to the present invention has a solubility parameter of 20MPa^1/2A polymer of a constituent unit of the above monomer (hereinafter, also referred to as "specific polymer").

In addition, the invention also comprises a solubility parameter of 20MPa^1/2The constituent unit of the above monomer is referred to as "specific constituent unit", and the solubility parameter is also 20MPa^1/2The above monomers are referred to as "specific monomers".

From the viewpoint of printing durability and on-press developability, the solubility parameter of the specific monomer is preferably 22MPa^1/2Above, more preferably 25MPa^1/2Above, more preferably 27MPa^1/2Above, particularly preferably 30MPa^1/2The above. The solubility parameter of the specific monomer is preferably 40MPa^1/2Hereinafter, more preferably 35MPa^1/2The following.

The solubility parameter (SP value) in the present invention is Hansen (Hansen) solubility parameter. Regarding the Hansen (Hansen) solubility parameter, the solubility parameter introduced by Hildebrand (Hildebrand) is divided into 3 of a dispersion term δ d, a polar term δ p, and a hydrogen bond term δ hIndividual components, and are shown in three-dimensional space, but in the present invention by δ [ MPa ]^1/2]The SP value is expressed, and a value calculated by the following formula is used.

δ[MPa^1/2]＝(δd²+δp²+δh²)^1/2

Further, the dispersion term δ d, the polarity term δ p, and the hydrogen bond term δ h are obtained in large numbers from Hansen or its research successor, and are described in detail in Polymer Handbook (fourth edition), VII-698-711.

Further, hansen solubility parameter values for a large number of Solvents or resins were investigated, and are described in Wesley l.

From the viewpoint of printing durability and on-press developability, the specific constituent unit preferably has at least 1 structure selected from the group consisting of an amide bond, an epoxy group, a cyano group, a hydroxyl group, an imide bond, a carbonate bond, a urethane bond, a urea bond, and a sulfonamide group, more preferably at least 1 structure selected from the group consisting of an amide bond, a hydroxyl group, and a sulfonamide group, and particularly preferably has 1 or more amide bonds and 1 or more at least 1 structure selected from the group consisting of a hydroxyl group and a sulfonamide group.

From the viewpoint of on-site developability, the specific constituent unit preferably has at least 1 structure selected from the group consisting of a urethane bond, a urea bond, a hydroxyl group, an amide group, and a cyano group, and more preferably has at least 1 structure selected from the group consisting of a urethane bond and a urea bond.

The specific polymer is preferably an addition polymerization type resin from the viewpoint of printing durability and on-press developability.

From the viewpoint of printing durability and on-press developability, the specific monomer is preferably a (meth) acrylate compound, (meth) acrylonitrile compound, maleimide compound or (meth) acrylamide compound, and more preferably a (meth) acrylamide compound.

The specific monomer is preferably an ethylenically unsaturated compound, and may be a monofunctional ethylenically unsaturated compound or a polyfunctional ethylenically unsaturated compound, but from the viewpoint of printing durability and on-press developability, a monofunctional ethylenically unsaturated compound is more preferable.

The specific polymer may or may not have a crosslinked structure, but a linear polymer is preferable from the viewpoint of on-site developability.

The molecular weight of the specific constituent unit is preferably 53 to 500, more preferably 53 to 400, and still more preferably 53 to 300.

Specific examples of the specific monomer include the following monomers.

[ chemical formula 1]

[ chemical formula 2]

[ chemical formula 3]

Examples of the constituent unit containing a specific monomer include the following constituent units containing N-vinylcaprolactam described above.

[ chemical formula 4]

When the specific constituent unit has a portion formed by a polymer reaction, such as a constituent unit having an ethylenically unsaturated group described later, the specific monomer is a monomer obtained by substituting a portion of the polymer chain in the specific constituent unit with an ethylenically unsaturated bond, and the solubility parameter is calculated.

The specific polymer may have 1 kind of specific constitutional unit alone or 2 or more kinds, but from the viewpoint of printing durability and on-press developability, it is preferably 2 or more kinds, more preferably 3 or more kinds.

From the viewpoint of printing durability and on-press developability, the specific polymer preferably has a specific constitutional unit having an ethylenically unsaturated group described later.

From the viewpoint of printing durability and on-press developability, the content of the specific constituent unit in the specific polymer is preferably 1 to 90 mol%, more preferably 5 to 75 mol%, still more preferably 10 to 60 mol%, and particularly preferably 15 to 45 mol%.

In the present invention, when the content of the "constituent unit" is defined in a molar ratio, the "constituent unit" and the "monomer unit" have the same meaning. In the present invention, the "monomer unit" may be modified by a polymer reaction or the like after polymerization. The same applies to the following.

Constituent unit with hydrophilic structure

From the viewpoint of on-site developability, the specific polymer preferably has a constituent unit having a hydrophilic structure.

The constituent unit having the hydrophilic structure may or may not correspond to a specific constituent unit.

From the viewpoint of UV printing durability and on-press developability, the specific polymer preferably has a polyalkylene oxide structure or a polyester structure as the hydrophilic structure, and more preferably has a polyalkylene oxide structure as the hydrophilic structure.

As the polyalkylene oxide structure, a polyethylene oxide structure, a polypropylene oxide structure, or a poly (ethylene oxide/propylene oxide) structure is preferable from the viewpoint of on-site developability.

From the viewpoint of on-press developability, the number of the alkylene oxide structures in the polyalkylene oxide structure is preferably 2 or more, more preferably 5 or more, further preferably 5 to 200, and particularly preferably 8 to 150.

The structure of the polyester is not particularly limited, but a ring-opening polymerization chain of a lactone and a polycondensation chain of a hydroxycarboxylic acid are preferably used.

From the viewpoint of on-site developability, the number of hydroxycarboxylic acid structures (lactone structures) in the polyester structure is preferably 2 or more, more preferably 2 to 20, further preferably 2 to 10, and particularly preferably 4 to 10.

From the viewpoint of UV printing durability and on-press developability, the specific polymer preferably has a constituent unit represented by the following formula A-1 or formula A-2, and more preferably has a constituent unit represented by the following formula A-1.

[ chemical formula 5]

In the formulae A-1 and A-2, L¹Represents ethylene or propylene, L²Represents an alkylene group having 2 to 10 carbon atoms, L³Represents an alkylene group having 1 to 10 carbon atoms, R¹And R³Each independently represents a hydrogen atom, an alkyl group or an aryl group, R²And R⁴Each independently represents a hydrogen atom or a methyl group, m1 represents an integer of 2 to 200, and m2 represents an integer of 2 to 20.

L¹Ethylene or 1, 2-propylene is preferred.

L²The alkylene group has preferably 2 to 8 carbon atoms, more preferably 2 to 4 carbon atoms, and still more preferably an ethylene group.

L³The alkylene group has preferably 2 to 8 carbon atoms, more preferably 3 to 8 carbon atoms, and still more preferably 4 to 6 carbon atoms.

R¹And R³Each independently preferably represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a methyl group.

m1 is preferably an integer of 2 to 200, more preferably an integer of 2 to 100, and further preferably an integer of 2 to 50.

m2 is preferably an integer of 2 to 10, more preferably 4 to 10.

From the viewpoint of on-site developability, the specific polymer preferably has a group represented by the following formula Z, and more preferably has a constituent unit having a group represented by the following formula Z.

-Q-W-Y formula Z

In formula Z, Q represents a divalent linking group, W represents a divalent group having a hydrophilic structure or a divalent group having a hydrophobic structure, and Y represents a monovalent group having a hydrophilic structure or a monovalent group having a hydrophobic structure, where either W or Y has a hydrophilic structure.

Q is preferably a divalent linking group having 1 to 20 carbon atoms, and more preferably a 2-valent linking group having 1 to 10 carbon atoms.

Q is preferably an alkylene group, an arylene group, an ester bond, an amide bond, or a combination of 2 or more thereof, and more preferably a phenylene group, an ester bond, or an amide bond.

The divalent group having a hydrophilic structure in W is preferably a polyalkyleneoxy group or a group having-CH bonded to one end of a polyalkyleneoxy group₂CH₂NR^W-a group of (a). In addition, R^WRepresents a hydrogen atom or an alkyl group.

The divalent group having a hydrophobic structure in W is preferably-R^WA-、-O-R^WA-O-、-R^WN-R^WA-NR^W-、-OOC-R^WA-O-or-OOC-R^WA-O-. In addition, R^WAEach independently represents a linear, branched or cyclic alkylene group having 6 to 120 carbon atoms, a halogenated alkylene group having 6 to 120 carbon atoms, an arylene group having 6 to 120 carbon atoms, an alkylenearyl group (divalent group obtained by removing 1 hydrogen atom from an alkylaryl group) having 6 to 120 carbon atoms, or an aralkylene group having 6 to 120 carbon atoms.

The monovalent group having a hydrophilic structure in Y is preferably OH, COOH, or-CH bonded to the other terminal of a polyalkyleneoxy group having a terminal hydrogen atom or alkyl group or a polyalkyleneoxy group having a terminal hydrogen atom or alkyl group₂CH₂N(R^W) -a group of (a).

Hydrophobicity in YThe monovalent group in the structure is preferably a linear, branched OR cyclic alkyl group having 6 to 120 carbon atoms, a haloalkyl group having 6 to 120 carbon atoms, an aryl group having 6 to 120 carbon atoms, an alkylaryl group (alkylaryl group) having 6 to 120 carbon atoms, an arylalkyl group having 6 to 120 carbon atoms, OR^WB、COOR^WBOr OOCR^WB. In addition, R^WBRepresents an alkyl group having 6 to 20 carbon atoms.

The specific polymer may have 1 kind of the constituent unit having a hydrophilic structure alone or 2 or more kinds.

From the viewpoint of on-site developability, the content of the constituent unit having a hydrophilic structure in the specific polymer is preferably 1 to 80 mol%, more preferably 10 to 70 mol%, and particularly preferably 20 to 60 mol%.

Constituent unit containing ethylenic unsaturated group

The specific polymer preferably has a constituent unit containing an ethylenically unsaturated group from the viewpoint of printing durability and on-press developability.

The constituent unit having the ethylenically unsaturated group may or may not correspond to a specific constituent unit.

The constituent unit having the above-mentioned ethylenically unsaturated group may be introduced by copolymerization or by a polymer reaction.

Examples of the polymer having an ethylenically unsaturated group in the main chain of the molecule include poly-1, 4-butadiene, poly-1, 4-isoprene and the like.

Examples of the polymer having an ethylenically unsaturated group in a side chain of a molecule include polymers of esters or amides of acrylic acid or methacrylic acid, wherein a residue of the ester or amide (-COOR or R of-CONHR) has an ethylenically unsaturated group.

Examples of the residue having an ethylenically unsaturated group (R) include- (CH)₂)_nCR^1A＝CR^2AR^3A、-(CH₂O)_nCH₂CR^1A＝CR^2AR^3A、-(CH₂CH₂O)_nCH₂CR^1A＝CR^2AR^3A、-(CH₂)_nNH-CO-O-CH₂CR^1A＝CR^2AR^3A、-(CH₂)_n-O-CO-CR^1A＝CR^2AR^3AAnd- (CH)₂CH₂O)₂-X^A(in the formula, R^A1～R^A3Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group or an aryloxy group, R^A1And R^A2Or R^A3May be bonded to each other to form a ring. n represents an integer of 1 to 10. X represents a dicyclopentadiene residue. ).

Specific examples of the ester residue include-CH₂CH＝CH₂、-CH₂CH₂O-CH₂CH＝CH₂、-CH₂C(CH₃)＝CH₂、-CH₂CH＝CH-C₆H₅、-CH₂CH₂OCOCH＝CH-C₆H₅、-CH₂CH₂-NHCOO-CH₂CH＝CH₂and-CH₂CH₂O-X (wherein X represents a dicyclopentadiene residue).

Specific examples of the amide residue include-CH₂CH＝CH₂、-CH₂CH₂-Y (wherein Y represents a cyclohexene residue) and-CH₂CH₂-OCO-CH＝CH₂。

The specific polymer may have 1 kind of the constitutional unit having an ethylenically unsaturated group alone or 2 or more kinds.

From the viewpoint of printing durability and on-press developability, the content of the constituent unit having an ethylenically unsaturated group in the specific polymer is preferably 1 to 60 mol%, more preferably 2 to 40 mol%, and particularly preferably 5 to 30 mol%.

The specific polymer may have a constituent unit (other constituent unit) other than the above-described constituent unit.

As a formation ofThe compound constituting the unit preferably has a solubility parameter of 20MPa^1/2The above-mentioned ethylenically unsaturated compounds such as styrene compounds, (meth) acrylate compounds, (meth) acrylamide compounds, vinyl halide compounds, vinyl ester compounds, vinyl ether compounds, and α -olefin compounds.

The specific polymer may have 1 kind of other constituent unit alone, may have 2 or more kinds, or may not have.

From the viewpoint of UV printing durability and on-press developability, the content of other constituent units in the intrinsic polymer is preferably 60 mol% or less, more preferably 50 mol% or less, even more preferably 40 mol% or less, and particularly preferably 20 mol% or less.

In the present invention, the following polymers B-1 to B-18 can be mentioned as specific polymers preferably used. The content of each constituent unit (subscript on the lower right of the bracket) is a molar ratio, and the subscript on the lower right of the bracket of the polyalkyleneoxy structure or polyhydroxycarboxylic acid structure represents the number of repetitions, and indicates the bonding position to another structure.

[ chemical formula 6]

[ chemical formula 7]

[ chemical formula 8]

[ chemical formula 9]

[ chemical formula 10]

[ chemical formula 11]

[ chemical formula 12]

The molecular weight of the specific polymer is preferably 2,000 or more, more preferably 5,000 or more, further preferably 5,000 to 300,000, and particularly preferably 8,000 to 200,000 in terms of polystyrene equivalent by GPC method.

In the image recording layer used in the present invention, 1 kind of the specific polymer may be used alone, or 2 or more kinds may be used simultaneously.

The specific polymer can be contained in the image recording layer in any content. The content of the binder polymer can be appropriately selected depending on the use of the image recording layer, and is preferably 1 to 90% by mass, and more preferably 5 to 80% by mass, based on the total mass of the image recording layer.

Infrared absorbers

The image recording layer contains an infrared absorber.

The infrared absorber has a function of converting absorbed infrared rays into heat and a function of transferring electrons and/or energy to a polymerization initiator described later by being excited by infrared rays. The infrared absorber used in the present invention is preferably a dye having an absorption maximum at a wavelength of 750nm to 1,400 nm.

As The dye, there can be used a commercially available dye and a known dye described in The literature such as "The Society of synthetic organic Chemistry", Japan, Ed., Showa 45's publication ". Specific examples thereof include azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinonimine dyes, methine dyes, cyanine dyes, squarylium cyanine dyes, pyrylium salts, metal thiolate complexes, and the like.

Preferable dyes among these dyes include cyanine dyes, squarylium cyanine dyes, pyrylium salts, nickel thiol complexes, and indocyanine dyes. More preferably, cyanine dyes and indocyanine dyes are used. Among them, cyanine is particularly preferable.

Specific examples of the cyanine dye include compounds described in paragraphs 0017 to 0019 of Japanese patent application laid-open No. 2001-133969, paragraphs 0016 to 0021 of Japanese patent application laid-open No. 2002-023360, and paragraphs 0012 to 0037 of Japanese patent application laid-open No. 2002-040638, preferably compounds described in paragraphs 0034 to 0041 of Japanese patent application laid-open No. 2002-278057, and paragraphs 0080 to 0086 of Japanese patent application laid-open No. 2008-195018, and particularly preferably compounds described in paragraphs 0035 to 0043 of Japanese patent application laid-open No. 0032007-090850, and paragraphs 0105 to 0113 of Japanese patent application laid-open No. 2012-206495.

Further, the compounds described in paragraphs 0008 to 0009 of Japanese patent application laid-open No. 5-005005 and paragraphs 0022 to 0025 of Japanese patent application laid-open No. 2001-222101 can also be preferably used.

As the pigment, the compounds described in paragraphs 0072 to 0076 of Japanese patent application laid-open No. 2008-195018 are preferred.

The infrared absorber may be used in 1 type alone, or 2 or more types may be used simultaneously. Further, as the infrared absorber, a pigment and a dye may be used together.

The content of the infrared absorbing dye in the image recording layer is preferably 0.1 to 10.0% by mass, and more preferably 0.5 to 5.0% by mass, based on the total mass of the image recording layer.

Polymer particles

The image recording layer contains polymer particles.

The polymer particles are preferably selected from the group consisting of thermoplastic polymer particles, thermoreactive polymer particles, polymer particles having a polymerizable group, microcapsules containing a hydrophobic compound, and microgels (crosslinked polymer particles). Among them, polymer particles or microgels having a polymerizable group are preferable. In a particularly preferred embodiment, the polymer particles comprise at least 1 ethylenically unsaturated polymerizable group. The presence of such polymer particles can provide an effect of improving printing durability in exposed portions and on-press developability in unexposed portions.

Also, the polymer particles are preferably thermoplastic polymer particles.

As the thermoplastic polymer particles, thermoplastic polymer particles described in, for example, Research Disclosure No.33303, Japanese patent application laid-open No. 9-123387, Japanese patent application laid-open No. 9-131850, Japanese patent application laid-open No. 9-171249, Japanese patent application laid-open No. 9-171250 and European patent application No. 931647, which are published in 1992, are preferable.

Specific examples of the polymer constituting the thermoplastic polymer particles include homopolymers or prepolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinylcarbazole, and acrylates or methacrylates having a polyalkylene structure, and mixtures thereof. Preferable examples thereof include a copolymer containing polystyrene, styrene and acrylonitrile, and polymethyl methacrylate. The thermoplastic polymer particles preferably have an average particle diameter of 0.01 to 3.0. mu.m.

Examples of the thermally reactive polymer particles include polymer particles having a thermally reactive group. The thermally reactive polymer particles form a hydrophobic region by crosslinking based on a thermal reaction and a change in functional groups when crosslinking is performed.

As the thermally reactive group in the polymer particle having a thermally reactive group, as long as a chemical bond can be formed, the functional group may be any functional group which can undergo any reaction, but is preferably a polymerizable group, and examples thereof include an ethylenically unsaturated group which undergoes a radical polymerization reaction (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), a cationically polymerizable group (for example, vinyl group, vinyloxy group, epoxy group, oxetanyl group, etc.), an isocyanate group or a block thereof which undergoes an addition reaction, an epoxy group, vinyloxy group, and a functional group having an active hydrogen atom which is a reaction target of these (for example, amino group, hydroxyl group, carboxyl group, etc.), a carboxyl group which undergoes a condensation reaction, a hydroxyl group or an amino group which is a reaction target, an acid anhydride which undergoes a ring-opening addition reaction, an amino group or a hydroxyl group which is a reaction target, and the like.

Examples of the microcapsules include those described in japanese patent application laid-open nos. 2001-277740 and 2001-277742, which contain at least a part of the components of the image recording layer in the interior of the microcapsules. The constituent components of the image recording layer may be contained outside the microcapsules. A preferable embodiment of the microcapsule-containing image recording layer has a structure in which a hydrophobic component is contained in the interior of the microcapsule and a hydrophilic component is contained in the exterior of the microcapsule.

The microgel (crosslinked polymer particles) may contain a part of the constituent components of the image recording layer on at least one of the surface and the inside thereof. In particular, from the viewpoint of image forming sensitivity or printing durability, a reactive microgel having a radical polymerizable group on the surface thereof is preferred.

In order to microencapsulate or microgel the constituent components of the image recording layer, a known method can be applied.

Further, as the polymer particles, from the viewpoint of printing durability, antifouling property and storage stability, polymer particles obtained by the reaction of a polyvalent isocyanate compound which is an adduct of a polyvalent phenol compound having 2 or more hydroxyl groups in the molecule and isophorone diisocyanate and a compound having active hydrogen are preferable.

The polyphenol compound is preferably a compound having a plurality of benzene rings having a phenolic hydroxyl group.

The compound having the active hydrogen is preferably a polyol compound or a polyamine compound, more preferably a polyol compound, and still more preferably at least 1 compound selected from the group consisting of propylene glycol, glycerin, and trimethylolpropane.

The resin particles obtained by the reaction of a polyvalent isocyanate compound which is an adduct of a polyvalent phenol compound having 2 or more hydroxyl groups in the molecule and isophorone diisocyanate and a compound having an active hydrogen are preferably polymer particles described in paragraphs 0032 to 0095 in Japanese patent laid-open No. 2012 and 206495.

Further, the polymer particles preferably have a hydrophobic main chain from the viewpoint of printing durability and solvent resistance, and include both i) a constituent unit having a side chain cyano group directly bonded to the hydrophobic main chain and ii) a constituent unit having a side group including a hydrophilic polyalkylene oxide segment.

The hydrophobic main chain preferably includes an acrylic resin chain.

Preferable examples of the cyano group as the side chain include- [ CH ]₂CH(C≡N)-]Or- [ CH ]₂C(CH₃)(C≡N)-]。

Also, the constituent unit having the above-mentioned side chain cyano group can be easily derived from an ethylenically unsaturated type monomer such as acrylonitrile or methacrylonitrile or a combination thereof.

Further, as the alkylene oxide in the hydrophilic polyalkylene oxide segment, ethylene oxide or propylene oxide is preferable, and ethylene oxide is more preferable.

The number of repeating alkylene oxide structures in the hydrophilic polyalkylene oxide segment is preferably 10 to 100, more preferably 25 to 75, and still more preferably 40 to 50.

The particles having a hydrophobic main chain and containing both i) a constituent unit having a side chain cyano group directly bonded to the hydrophobic main chain and ii) a constituent unit having a pendant group containing a hydrophilic polyalkylene oxide segment preferably include particles described in paragraphs 0039 to 0068 of japanese patent application laid-open No. 2008-503365.

The average particle diameter of the polymer particles is preferably 0.01 to 3.0. mu.m, more preferably 0.03 to 2.0. mu.m, and still more preferably 0.10 to 1.0. mu.m. Good resolution and stability over time are obtained in this range.

The average primary particle diameter of each particle in the present invention is measured by a light scattering method, or an electron micrograph of the particle is taken, and the particle diameters of 5,000 particles in total are measured on the micrograph, and the average value is calculated. In addition, regarding the non-spherical particles, the particle diameter value of spherical particles having the same particle area as the particle area on the photograph is taken as the particle diameter.

The average particle size in the present invention is a volume average particle size unless otherwise specified.

The content of the polymer particles is preferably 5 to 90 mass% with respect to the total mass of the image recording layer.

Polymerization initiators

The image recording layer used in the present invention preferably contains a polymerization initiator, and more preferably contains a polymerization initiator and a polymerizable compound.

The polymerization initiator is a compound that initiates and accelerates polymerization of the polymerizable compound. As the polymerization initiator, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation ability, a photopolymerization initiator, or the like can be used. Specifically, the radical polymerization initiators described in paragraphs 0092 to 0106 of Japanese patent application laid-open No. 2014-104631 can be used.

Among the polymerization initiators, onium salts are preferable. Among them, an iodonium salt and a sulfonium salt are particularly preferable. Preferred specific compounds for each salt are the same as those described in paragraphs 0104 to 0106 of Japanese patent application laid-open No. 2014-104631.

The content of the polymerization initiator is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass, based on the total mass of the image recording layer. Within the above range, more favorable sensitivity and more favorable staining resistance of the non-image portion during printing can be obtained.

Polymerizable compound-

The image recording layer used in the present invention preferably contains a polymerizable compound.

The polymerizable compound used in the image recording layer may be, for example, a radical polymerizable compound or a cation polymerizable compound, and is preferably an addition polymerizable compound (ethylenically unsaturated compound) having at least 1 ethylenically unsaturated bond. The ethylenically unsaturated compound is preferably a compound having at least 1 terminal ethylenically unsaturated bond, and more preferably a compound having 2 or more terminal ethylenically unsaturated bonds. The polymerizable compound may have a chemical form such as a monomer, a prepolymer, that is, a dimer, a trimer, or an oligomer, or a mixture thereof.

Examples of the monomer include unsaturated carboxylic acids (e.g., acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid), and ethers and amides thereof. Preferred are esters of unsaturated carboxylic acids and polyhydric alcohol compounds and amides of unsaturated carboxylic acids and polyhydric amine compounds. Further, addition reaction products of unsaturated carboxylic acid esters or amides having a nucleophilic substituent such as a hydroxyl group, an amino group, or a mercapto group with monofunctional or polyfunctional isocyanates or epoxies, dehydration condensation reaction products with monofunctional or polyfunctional carboxylic acids, and the like are preferably used. Further, addition reaction products of unsaturated carboxylic acid esters or amides having electrophilic substituent groups such as isocyanate group and epoxy group with monofunctional or polyfunctional alcohols, amines and thiols are preferable, and substitution reaction products of unsaturated carboxylic acid esters or amides having leaving substituent groups such as halogen atom and tosyloxy group with monofunctional or polyfunctional alcohols, amines and thiols are more preferable. As another example, a compound group in which the unsaturated carboxylic acid is substituted with an unsaturated phosphonic acid, styrene, vinyl ether, or the like can be used. These compounds are described in Japanese patent laid-open Nos. 2006-508380, 2002-287344, 2008-256850, 2001-342222, 9-179296, 9-179297, 9-179298, 2004-294935, 2006-243493, 2002-275129, 2003-064130, 2003-280187, and 10-333321.

Specific examples of the ester monomer of the polyol compound and the unsaturated carboxylic acid include ethylene glycol diacrylate, 1, 3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, ethylene oxide isocyanurate (EO) -modified triacrylate, and polyester acrylate oligomer. Examples of the methacrylate include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, neopentyl glycol trimethacrylate, bis [ p- (3-methacryloyloxy-2-hydroxypropoxy) phenyl ] dimethylmethane, bis [ p- (methacryloyloxyethoxy) phenyl ] dimethylmethane and the like. Specific examples of the amide monomer of the polyamine compound and the unsaturated carboxylic acid include methylenebisacrylamide, methylenebismethacrylamide, 1, 6-hexamethylenebisacrylamide, diethylenetriaminetriacrylate, xylylenebisacrylamide, diphenylenedimethacrylamide, and the like.

Further, urethane addition polymerizable compounds produced by the addition reaction of isocyanate and hydroxyl group are also preferable, and specific examples thereof include vinyl urethane compounds containing 2 or more polymerizable vinyl groups in 1 molecule, which are obtained by adding a polyisocyanate compound having 2 or more isocyanate groups in 1 molecule and a hydroxyl group-containing vinyl monomer represented by the following formula (M), as described in japanese patent publication No. 48-041708.

CH₂＝C(R^M4)COOCH₂CH(R^M5)OH (M)

In the formula (M), R^M4And R^M5Each independently represents a hydrogen atom or a methyl group.

Further, the urethane acrylates described in Japanese patent laid-open Nos. 51-037193, 2-032293, 2-016765, 2003-344997 and 2006-065210, 58-049860, 56-017654 and 62-039417, urethane acrylate compounds having an ethylene oxide skeleton as described in Japanese patent publication No. 62-039418, Japanese patent publication No. 2000-250211 and Japanese patent publication No. 2007-094138, and urethane acrylate compounds having a hydrophilic group as described in U.S. Pat. No. 7153632, Japanese patent application No. 8-505958, Japanese patent publication No. 2007-coza293221 and Japanese patent publication No. 2007-coza293223 are also preferable.

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

Other binder polymers

The image recording layer used in the present invention may further contain other binder polymers than the specific polymer.

As the other binder polymer, a (meth) acrylic resin, a polyvinyl acetal resin, or a polyurethane resin is preferable.

Among them, other binder polymers can preferably use known binder polymers used in the image-recording layer of the lithographic printing plate precursor. As an example, a binder polymer used for an on-press development type lithographic printing plate precursor (hereinafter, also referred to as an on-press development binder polymer) is described in detail.

As the binder polymer for on-press development, a binder polymer having an alkylene oxide chain is preferable. The adhesive polymer having an alkylene oxide chain may have a poly (alkylene oxide) site in the main chain or may have a side chain. The graft polymer may have a poly (alkylene oxide) in a side chain, or may be a block copolymer of a block material comprising repeating units containing a poly (alkylene oxide) and a block material comprising repeating units not containing a poly (alkylene oxide).

When having poly (alkylene oxide) sites in the main chain, polyurethane resins are preferred. Examples of the polymer of the main chain in the case where the side chain has a poly (alkylene oxide) site include a (meth) acrylic resin, a polyvinyl acetal resin, a polyurethane resin, a polyurea resin, a polyimide resin, a polyamide resin, an epoxy resin, a polystyrene resin, a novolac-type phenol resin, a polyester resin, a synthetic rubber, and a natural rubber, and a (meth) acrylic resin is particularly preferable.

The molecular weight of the other binder polymer is preferably 2,000 or more, more preferably 5,000 or more, and still more preferably 10,000 to 300,000 in terms of polystyrene equivalent by GPC.

If necessary, a hydrophilic polymer such as polyacrylic acid or polyvinyl alcohol described in Japanese patent application laid-open No. 2008-195018 can be used in combination. Further, it is also possible to use both the lipophilic polymer and the hydrophilic polymer.

In the image recording layer used in the present invention, 1 kind of other binder polymer may be used alone, or 2 or more kinds may be used simultaneously.

Preferably, the content of the other binder polymer is less than the content of the specific polymer.

The content of the other binder polymer is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 1% by mass or less, and particularly preferably no other binder polymer is contained, based on the total mass of the image recording layer.

Auxiliary agents for the formation of free radicals

The image recording layer used in the present invention may contain a radical generation aid. The radical-generating auxiliary agent contributes to improvement of printing durability in a lithographic printing plate. Examples of the radical generation aid include the following 5 types.

(i) Alkyl or arylate type complexes: it is believed that the carbon-heterobonds are oxidatively cleaved and active radicals are generated. Specifically, a borate compound and the like can be given.

(ii) Aminoacetic acid compound: it is considered that the C — X bond on the carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. As X, a hydrogen atom, a carboxyl group, a trimethylsilyl group or a benzyl group is preferable. Specific examples thereof include N-phenylglycine (which may have a substituent on the phenyl group), N-phenyliminodiacetic acid (which may have a substituent on the phenyl group), and the like.

(iii) A sulfur-containing compound: the compound obtained by substituting the nitrogen atom of the glycine compound with a sulfur atom is considered to generate an active radical by the same action. Specifically, there may be mentioned phenylthioacetic acid (which may have a substituent in the phenyl group), and the like.

(iv) A tin-containing compound: the compound obtained by substituting the nitrogen atom of the glycine compound with a tin atom can generate an active radical by the same action.

(v) Sulfinates: reactive radicals can be generated by oxidation. Specifically, sodium arylsulfinate and the like can be given.

Among these radical generation aids, the image recording layer preferably contains a borate compound. The borate compound is preferably a tetraarylborate compound or a monoalkyltriarylborate compound, more preferably a tetraarylborate compound from the viewpoint of the stability of the compound and the potential difference described later, and particularly preferably a tetraarylborate compound having 1 or more aryl groups having an electron-withdrawing group from the viewpoint of the potential difference described later.

The electron-withdrawing group is preferably a group having a positive σ value of Hammett's equation, and more preferably a group having a σ value of 0 to 1.2 of Hammett's equation. The σ values (σ p value and σ m value) of hamett are described in detail in Hansch, c.; leo, a.; taft, r.w., chem.rev., 1991, 91, 165-wall 195.

The electron-withdrawing group is preferably a halogen atom, a trifluoromethyl group or a cyano group, and more preferably a fluorine atom, a chlorine atom, a trifluoromethyl group or a cyano group.

The counter cation of the borate compound is preferably an alkali metal ion or a tetraalkylammonium ion, and more preferably a sodium ion, a potassium ion, or a tetrabutylammonium ion.

Specific examples of the borate compound include those shown below. Wherein, X_c ⁺Denotes a monovalent cation, preferably an alkali metal ion or a tetraalkylammonium ion, more preferably an alkali metal ion or a tetrabutylammonium ion. And Bu represents n-butyl.

[ chemical formula 13]

[ chemical formula 14]

[ chemical formula 15]

[ chemical formula 16]

The radical-generating auxiliary may be added in 1 type or 2 or more types at the same time.

The content of the radical generation aid is preferably 0.01 to 30% by mass, more preferably 0.05 to 25% by mass, and still more preferably 0.1 to 20% by mass, based on the total mass of the image recording layer.

Chain transfer agents

The image recording layer used in the present invention may contain a chain transfer agent. The chain transfer agent helps improve printing durability in a lithographic printing plate.

The chain transfer agent is preferably a thiol compound, more preferably a thiol having 7 or more carbon atoms, and still more preferably a compound having a mercapto group on an aromatic ring (aromatic thiol compound), from the viewpoint of a boiling point (low volatility). The thiol compound is preferably a monofunctional thiol compound.

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

[ chemical formula 17]

[ chemical formula 18]

[ chemical formula 19]

[ chemical formula 20]

The chain transfer agent may be added in 1 kind alone, or may be used in combination of 2 or more kinds.

The content of the chain transfer agent is preferably 0.01 to 50% by mass, more preferably 0.05 to 40% by mass, and still more preferably 0.1 to 30% by mass, based on the total mass of the image recording layer.

Low molecular hydrophilic compounds-

In order to suppress a decrease in printing durability and improve on-press developability, the image recording layer may contain a low-molecular hydrophilic compound. The low-molecular 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.

Examples of the low-molecular hydrophilic compound include water-soluble organic compounds such as glycols and ether or ester derivatives thereof, e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol, polyhydric alcohols such as glycerin, neopentylglycol, and tris (2-hydroxyethyl) isocyanurate, organic amines and salts thereof, e.g., triethanolamine, diethanolamine, and monoethanolamine, organic sulfonic acids and salts thereof, e.g., alkylsulfonic acids, e.g., p-toluenesulfonic acid, and benzenesulfonic acid, organic sulfamic acids and salts thereof, e.g., alkylsulfuric acid, and alkylethersulfuric acid, organic phosphonic acids and salts thereof, e.g., phenylphosphonic acid, organic phosphonic acids and salts thereof, e.g., tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, and amino acids, and salts thereof, and betaines.

The low-molecular hydrophilic compound preferably contains at least 1 selected from the group consisting of polyols, organic sulfates, organic sulfonates, and betaines.

Specific examples of the organic sulfonate include alkylsulfonic acid salts such as n-butylsodium sulfonate, n-hexylsodium sulfonate, 2-ethylhexylsodium sulfonate, cyclohexylsodium sulfonate, and n-octylsodium sulfonate; alkyl sulfonates containing an oxyethylene chain, such as 5,8, 11-trioxadecane-1-sulfonic acid sodium salt, 13-ethyl-5, 8, 11-trioxadecane-1-sulfonic acid sodium salt, 5,8,11, 14-tetraoxatetracosane-1-sulfonic acid sodium salt; arylsulfonic acid salts such as sodium benzenesulfonate, sodium p-toluenesulfonate, sodium p-hydroxybenzenesulfonate, sodium p-styrenesulfonate, dimethyl isophthalate-5-sulfonate, sodium 1-naphthalenesulfonate, sodium 4-hydroxynaphthalenesulfonate, disodium 1, 5-naphthalenedisulfonate, trisodium 1,3, 6-naphthalenetrisulfonate, etc.; and compounds described in paragraphs 0026 to 0031 of Japanese patent laid-open publication No. 2007 & 276454 and paragraphs 0020 to 0047 of Japanese patent laid-open publication No. 2009 & 154525. The salt can be potassium salt or lithium salt.

Examples of the organic sulfates include sulfates of alkyl, alkenyl, alkynyl, aryl or heterocyclic monoether of polyethylene oxide. The number of ethylene oxide units is preferably 1 to 4, and the salt is preferably a sodium salt, a potassium salt or a lithium salt. Specific examples thereof include compounds described in paragraphs 0034 to 0038 of Japanese patent application laid-open No. 2007-276454.

The betaine is preferably a compound having 1 to 5 carbon atoms in the hydrocarbon substituent of the nitrogen atom, and specific examples thereof include trimethylammonium acetate, dimethylpropylammonium acetate, 3-hydroxy-4-trimethylammonium butyrate, 4- (1-pyridyl) butyrate, 1-hydroxyethyl-1-imidazolium acetate, trimethylammonium methanesulfonate, dimethylpropylammonium methanesulfonate, 3-trimethylammonium-1-propanesulfonate, and 3- (1-pyridyl) -1-propanesulfonate.

Since the low-molecular hydrophilic compound has a small structure of the hydrophobic portion and hardly has a surface active effect, the dampening solution does not penetrate into the exposed portion (image portion) of the image recording layer to lower the hydrophobicity or film formation strength of the image portion, and the ink receptivity and printing durability of the image recording layer can be maintained satisfactorily.

The content of the low-molecular hydrophilic compound is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, and still more preferably 2 to 10% by mass, based on the total mass of the image recording layer. Within this range, good on-press developability and printing durability can be obtained.

The low-molecular hydrophilic compound may be used alone in 1 kind, or may be used in combination with 2 or more kinds.

Lipotropizing agent

In order to improve the ink-receiving property, 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 particular, when the protective layer contains an inorganic layered compound, these compounds can function as a surface coating agent for the inorganic layered compound, and can suppress a decrease in the ink adhesion during printing with the inorganic layered compound.

The fat-sensitive agent is preferably a combination of a phosphonium compound, a nitrogen-containing low-molecular-weight compound and an ammonium group-containing polymer, and more preferably a combination of a phosphonium compound, a quaternary ammonium salt and an ammonium group-containing polymer.

Examples of the phosphonium compound include those described in Japanese patent laid-open Nos. 2006-297907 and 2007-050660. Specific examples thereof include tetrabutyliodophosphine, butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, 1, 4-bis (triphenylphosphine) butane-bis (hexafluorophosphate), 1, 7-bis (triphenylphosphine) heptane-sulfate, 1, 9-bis (triphenylphosphine) nonane-naphthalene-2, 7-disulfonate, and the like.

Examples of the nitrogen-containing low-molecular-weight compound include amine salts and quaternary ammonium salts. Furthermore, imidazolinium salts, benzimidazolinium salts, pyridinium salts and quinolinium salts are also included. Among them, quaternary ammonium salts and pyridinium salts are preferable. Specific examples thereof include tetramethylammonium ═ hexafluorophosphate, tetrabutylammonium ═ hexafluorophosphate, dodecyltrimethylammonium ═ p-toluenesulfonic acid, benzyltriethylammonium ═ hexafluorophosphate, benzyldimethyloctylammonium ═ hexafluorophosphate, benzyldimethyldodecylammonium ═ hexafluorophosphate, the compounds described in paragraphs 0021 to 0037 of Japanese patent laid-open No. 2008-284858 and paragraphs 0030 to 0057 of Japanese patent laid-open No. 2009-090645.

The ammonium group-containing polymer may have an ammonium group in its structure, and is preferably a polymer containing 5 to 80 mol% of a (meth) acrylate having an ammonium group in a side chain as a copolymerization component. Specific examples thereof include polymers described in paragraphs 0089 to 0105 of Japanese patent application laid-open No. 2009-208458.

The value of reduced viscosity (unit: ml/g) of the ammonium salt-containing polymer determined by the measurement method described in Japanese patent laid-open No. 2009-208458 is preferably in the range of 5 to 120, more preferably in the range of 10 to 110, and particularly preferably in the range of 15 to 100. The reduced viscosity is preferably 10,000 to 150,0000, more preferably 17,000 to 140,000, and particularly preferably 20,000 to 130,000 in terms of the weight average molecular weight (Mw).

Specific examples of the ammonium group-containing polymer are shown below.

(1)2- (Trimethylammonium) ethylmethacrylate/p-toluenesulfonate/3, 6-dioxaheptyl methacrylate copolymer (molar ratio 10/90, Mw 4.5 ten thousand)

(2)2- (Trimethylammonium) ethyl methacrylate hexafluorophosphate/3, 6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 6.0 ten thousand)

(3)2- (Ethyldimethylammoniumyl) methacrylate Ethyl p-toluenesulfonate/hexyl methacrylate copolymer (molar ratio 30/70, Mw 4.5 ten thousand)

(4)2- (trimethylammonium) ethyl methacrylate hexafluorophosphate/2-ethylhexyl methacrylate copolymer (molar ratio 20/80, Mw 6.0 ten thousand)

(5)2- (Trimethylammonium) ethyl methacrylate-methyl sulfate/hexyl methacrylate copolymer (molar ratio 40/60, Mw 7.0 ten thousand)

(6)2- (Butyldimethylammonium) ethyl methacrylate hexafluorophosphate/3, 6-dioxaheptyl methacrylate copolymer (molar ratio 25/75, Mw 6.5 ten thousand)

(7)2- (Butyldimethylammonium) acrylic acid ethyl ester hexafluorophosphate/3, 6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 6.5 ten thousand)

(8)2- (Butyldimethylammonium) methacrylate Ethyl ester 13-Ethyl-5, 8, 11-trioxa-1-heptadecanesulfonate/3, 6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 7.5 ten thousand)

(9)2- (Butyldimethylammonium) methacrylate Ethyl ester Hexafluorophosphate/3, 6-dioxaheptyl methacrylate/2-hydroxy-3-methacryloxypropyl methacrylate copolymer (molar ratio 15/80/5, Mw 6.5 ten thousand)

The content of the fat-sensitive agent is preferably 0.01 to 30.0 mass%, more preferably 0.1 to 15.0 mass%, and particularly preferably 1 to 10 mass% with respect to the total mass of the image recording layer.

Acid color developers

The image recording layer used in the present invention preferably contains an acid developer.

The "acid developer" used in the present invention is a compound having a property of developing color by heating in a state of receiving an electron accepting compound (for example, a proton such as an acid). The acid color developer particularly has a partial skeleton such as a lactone, a lactam, a sultone, a spiropyran, an ester, or an amide, and is preferably a colorless compound in which the partial skeleton is rapidly opened or cleaved when it is brought into contact with an electron-accepting compound.

Examples of such an acid developer include 3, 3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide (referred to as "crystal violet lactone"), 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-bis (1, 2-dimethylindol-3-yl) -5-dimethylaminophthalide, and, 3, 3-bis (1, 2-dimethylindol-3-yl) -6-dimethylaminobenzphthalide, 3-bis (9-ethylcarbazol-3-yl) -6-dimethylaminobenzphthalide, 3-bis (2-phenylindol-3-yl) -6-dimethylaminobenzphthalide, 3- (4-dimethylaminophenyl) -3- (1-methylpyrrol-3-yl) -6-dimethylaminobenzphthalide,

3, 3-bis [1, 1-bis (4-dimethylaminophenyl) ethen-2-yl ] -4,5,6, 7-tetrachlorophthalide, 3-bis [1, 1-bis (4-pyrrolidinophenyl) ethen-2-yl ] -4,5,6, 7-tetrabromophthalide, 3-bis [1- (4-dimethylaminophenyl) -1- (4-methoxyphenyl) ethen-2-yl ] -4,5,6, 7-tetrachlorophthalide, 3-bis [1- (4-pyrrolidinophenyl) -1- (4-methoxyphenyl) ethen-2-yl ] -4,5,6, 7-tetrachlorophthalide, 3- [1, 1-bis (1-ethyl-2-methylindol-3-yl) ethen-2-yl ] -3- (4-diethylaminophenyl) phthalide, 3- [1, 1-bis (1-ethyl-2-methylindol-3-yl) ethen-2-yl ] -3- (4-N-ethyl-N-phenylaminophenyl) phthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-N-octyl-2-methylindol-3-yl) -phthalide, 3-bis (1-N-octyl-2-methylindol-3-yl) -phthalide, 3- (2-methyl-4-diethylaminophenyl) -3- (1-N-octylamino) Phthalides such as phenyl-2-methylindol-3-yl-phthalide,

4, 4-bis-dimethylaminobenzopropanol benzyl ether, N-halophenyl-leuco auramine (leuco-auramine), N-2,4, 5-trichlorophenyl-leuco auramine, rhodamine-B-anilinolactam, rhodamine- (4-nitrophenylamino) lactam, rhodamine-B- (4-chlorophenylamino) lactam, 3, 7-bis (diethylamino) -10-benzoylphenazine, benzoyl leuco methylene blue, 4-nitrobenzoyl methylene blue, N-halophenyl-leuco auramine (leuco-auramine), N-2,4, 5-trichlorophenyl-leuco auramine (rhodamine-B-chlorophenylamino) -lactam, N-benzoylaniline, N-phenylthiopropionic acid,

3, 6-dimethoxyfluorane, 3-dimethylamino-7-methoxyfluorane, 3-diethylamino-6-methoxyfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6, 7-dimethylfluorane, 3-N-hexyl-N-N-butylamino-7-methylfluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7-di-N-hexylaminofluorane, 3-diethylamino-7-phenylaminofluorane, a salt thereof, and a pharmaceutically acceptable carrier, 3-diethylamino-7- (2' -fluoroanilino) fluoran, 3-diethylamino-7- (2' -chloroanilino) fluoran, 3-diethylamino-7- (3' -chloroanilino) fluoran, 3-diethylamino-7- (2', 3' -dichloroanilino) fluoran, 3-diethylamino-7- (3' -trifluoromethylphenylamino) fluoran, 3-di-N-butylamino-7- (2' -fluoroanilino) fluoran, 3-di-N-butylamino-7- (2' -chloroanilino) fluoran, 3-N-isopentyl-N-ethylamino-7- (2' -chloroanilino) fluoran, a salt thereof, a hydrate,

3-N-N-hexyl-N-ethylamino-7- (2' -chlorophenylamino) fluorane, 3-diethylamino-6-chloro-7-phenylaminofluorane, 3-di-N-butylamino-6-chloro-7-phenylaminofluorane, 3-diethylamino-6-methoxy-7-phenylaminofluorane, 3-di-N-butylamino-6-ethoxy-7-phenylaminofluorane, 3-pyrrolo-6-methyl-7-phenylaminofluorane, 3-hydropyridyl-6-methyl-7-phenylaminofluorane, 3-morpholinyl-6-methyl-7-phenylaminofluorane, 3-dimethylamino-6-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-phenylaminofluorane, 3-chloro-7-phenylaminofluorane, 3-diethylamino-6-ethoxy-7-phenylaminofluorane, 3-di-, 3-diethylamino-6-methyl-7-anilinofluoran, 3-di-N-butylamino-6-methyl-7-anilinofluoran, 3-di-N-pentylamino-6-methyl-7-anilinofluoran, 3-N-ethyl-N-methylamino-6-methyl-7-anilinofluoran, 3-N-N-propyl-N-ethylamino-6-methyl-7-anilinofluoran, 3-N-N-butyl-N-methylamino-6-methyl-7-anilinofluoran, 3-N-N-butylamino-N-methylamino-6-methyl-7-anilinofluoran, 3-N-N-butyl-N-ethylamino-6-methyl-7-phenylaminofluorane, 3-N-isobutyl-N-methylamino-6-methyl-7-phenylaminofluorane, 3-N-isobutyl-N-ethylamino-6-methyl-7-phenylaminofluorane, 3-N-isopentyl-N-ethylamino-6-methyl-7-phenylaminofluorane, 3-N-N-hexyl-N-methylamino-6-methyl-7-phenylaminofluorane, 3-N-cyclohexyl-N-ethylamino-6-methyl-7-phenylaminofluorane, 3-N-cyclohexyl-N-N-propylamino-6-methyl-7-propalanine Benoxafluorane, 3-N-cyclohexyl-N-N-butyl-6-methyl-7-benoxafluorane, 3-N-cyclohexyl-N-N-hexylamino-6-methyl-7-benoxafluorane, 3-N-cyclohexyl-N-octylamino-6-methyl-7-benoxafluorane, benzofluorane, benzo,

3-N- (2 '-methoxyethyl) -N-methylamino-6-methyl-7-phenylaminofluorane, 3-N- (2' -methoxyethyl) -N-ethylamino-6-methyl-7-phenylaminofluorane, 3-N- (2 '-methoxyethyl) -N-isobutylamino-6-methyl-7-phenylaminofluorane, 3-N- (2' -ethoxyethyl) -N-methylamino-6-methyl-7-phenylaminofluorane, 3-N- (2 '-ethoxyethyl) -N-ethylamino-6-methyl-7-phenylaminofluorane, 3-N- (3' -methoxypropyl) -N-methylamino-6- Methyl-7-anilinofluoran, 3-N- (3' -methoxypropyl) -N-ethylamino-6-methyl-7-anilinofluoran, 3-N- (3' -ethoxypropyl) -N-methylamino-6-methyl-7-anilinofluoran, 3-N- (3' -ethoxypropyl) -N-ethylamino-6-methyl-7-anilinofluoran, 3-N- (2' -tetrahydrofurfuryl) -N-ethylamino-6-methyl-7-anilinofluoran, 3-N- (4' -tolyl) -N-ethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-ethyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (3' -tolylamino) fluoran, 3-diethylamino-6-methyl-7- (2', 6' -ditoluylamino) fluoran, 3-di-N-butylamino-7- (2', 6' -ditoluylamino) fluoran, 2-bis [4' - (3-N-cyclohexyl-N-methylamino-6-methylfluoran) -7-ylaminophenyl ] propane, 3- [4' - (4-anilinophenyl) aminophenyl ] amino-6-methylsulfanyl- Fluorans such as 7-chlorofluorane and 3- [4' - (dimethylaminophenyl) ] amino-5, 7-difluorane,

3- (2-methyl-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-n-propoxycarbonylamino-4-di-n-propylamino-phenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-methylamino-4-di-n-propylamino-phenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-methyl-4-di-n-hexylaminophenyl) -3- (1-n-octyl-2-methylindol-3-yl) propanamide 4, 7-diazophthalide, 3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3-bis (1-n-octyl-2-methylindol-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-methylaminophenyl) Isoindol-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, 3- (2-butoxy-4-diethylaminophenyl) -3- (1-ethyl-2-phenylindol-3-yl) -4 or 7-azaphthalide 3-methyl-spiro-dinaphthopyran, Phthalides such as 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-9-spiro-3 '- (6' -dimethylamino) phthalide, and 3, 6-bis (diethylamino) fluorene-9-spiro-3 '- (6' -dimethylamino) phthalide, and the like,

In addition to these, 2' -phenylamino-6 ' - (N-ethyl-N-isoamyl) amino-3 ' -methylspiro [ isobenzofuran-1 (3H), 9' - (9H) xanthene ] -3-one, 2' -phenylamino-6 ' - (N-ethyl-N- (4-methylphenyl)) amino-3 ' -methylspiro [ isobenzofuran-1 (3H), 9' - (9H) xanthene ] -3-one, 3' -N, N-dibenzylamino-6 ' -N, N-diethylaminospiro [ isobenzofuran-1 (3H), 9' - (9H) xanthene ] -3-one, 2' - (N-methyl-N-phenyl) amino-6 ' - (N-ethyl-N-methylphenyl) xanthene - (4-tolyl)) aminospiro [ isobenzofuran-1 (3H), 9' - (9H) xanthen ] -3-one, and the like.

Among the above, the acid color developer used in the present invention is preferably at least 1 compound selected from the group consisting of spiropyran compounds, spirooxazine compounds, spirolactone compounds, and spirolactam compounds.

From the viewpoint of visibility, the color of the colored pigment is preferably green, blue or black.

Commercially available products may be used as the acid color-developing agent, and examples thereof include ETAC, RED500, RED520, CVL, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, BLUE220, H-3035, BLUE203, ATP, H-1046, H-2114 (Fukui Yamada Chemical Co., Ltd., supra), ORGE-DCF, Vermilion-DCF, PINK-DCF, RED-DCF, BLMB, CVL, GREEN-DCF, TH-107 (HODOGAYA CHEMICAL CO., LTD. TM.), ODB-2, ODB-4, ODB-250, YAB-BlackXV, BLUE-63, BLUE-502, GN-169, YAG-2, Green-118, and crystal lactone (Red Co., Ltd., Black 169, Red Co., Black 8, Red Co., Ltd., Crystal). Among these commercially available products, ETAC, S-205, BLACK305, BLACK400, BLACK100, BLACK500, H-7001, GREEN300, NIRBLACK78, H-3035, ATP, H-1046, H-2114, GREEN-DCF, Blue-63, GN-169, and crystal violet lactone are preferable because the visible light absorption of the formed film is good.

These acid color developers may be used alone in 1 kind, or may be used in combination with 2 or more kinds of components.

Colorants-

The image-recording layer of the lithographic printing plate precursor according to the present invention can contain a dye having a large absorption in the visible light region as a colorant for an image. Specifically, there can be mentioned dyes described in oil yellow #101, oil yellow #103, oil powder #312, oil green BG, oil blue BOS, oil blue #603, oil black BY, oil black BS, oil black T-505 (above: ORIENT CHEMICAL industries, ltd.), victoria pure blue, crystal violet (CI42555), methyl violet (CI42535), ethyl violet 6HNAPS, rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI52015) and japanese unexamined patent publication No. sho 62-293247. Further, pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide are preferably used. The colorant is preferably contained because it can easily distinguish between an image portion and a non-image portion after image formation.

The amount of the colorant added is preferably 0.005 to 10% by mass based on the total mass of the image recording layer.

Other ingredients-

The image recording layer may contain, as other components, a surfactant, a polymerization inhibitor, a higher fatty acid derivative, a plasticizer, inorganic particles, an inorganic layered compound, and the like. Specifically, reference can be made to the description of paragraphs 0114 to 0159 of japanese patent application laid-open No. 2008-284817.

Formation of the image recording layer

The image recording layer in the lithographic printing plate precursor according to the present invention can be formed by, for example, preparing a coating solution by dispersing or dissolving the above-mentioned components in a known solvent, applying the coating solution on a support by a known method such as bar coater coating, and drying the coating solution, as described in paragraphs 0142 to 0143 of jp 2008-195018 a. The amount of the image recording layer (solid content) after coating and drying varies depending on the application, but is preferably 0.3g/m²～3.0g/m². Within this range, good sensitivity and good film formation characteristics of the image recording layer can be obtained.

< hydrophilic support >

The hydrophilic support in the lithographic printing plate precursor according to the present invention (hereinafter, also simply referred to as "support") can be appropriately selected from known hydrophilic supports for lithographic printing plate precursors and used. As the hydrophilic support, an aluminum plate subjected to roughening treatment by a known method and anodic oxidation treatment is preferable.

The aluminum plate may be further processed by appropriately selecting the following processes as required: the pore enlargement or pore sealing treatment of the anodic oxide film described in jp 2001-253181 a and jp 2001-322365 a, the surface hydrophilization treatment based on alkali metal silicate described in the specifications of U.S. Pat. No. 2,714,066, U.S. Pat. No.3,181,461, U.S. Pat. nos. 3,280,734 and U.S. Pat. No.3,902,734, and the surface hydrophilization treatment based on polyvinylphosphonic acid or the like described in the specifications of U.S. Pat. No.3,276,868, U.S. Pat. No. 4,153,461 and U.S. Pat. No. 4,689,272.

The center line average roughness of the support is preferably 0.10 to 1.2. mu.m.

The support may have a back coat layer containing an organic polymer compound described in Japanese patent application laid-open No. 5-045885 or a silicon alkoxide compound described in Japanese patent application laid-open No. 6-035174 on the surface on the side opposite to the image recording layer, as necessary.

< undercoat layer >

The lithographic printing plate precursor according to the present invention preferably has an undercoat layer (also referred to as an intermediate layer) between the image-recording layer and the support. The undercoat layer enhances adhesion between the support and the image recording layer in the exposed portion, and makes the image recording layer easily peelable from the support in the unexposed portion, and therefore the undercoat layer contributes to improvement of developability without impairing printing durability. In addition, in the case of infrared laser exposure, the undercoat layer functions as a heat-insulating layer, and thus the effect of preventing the sensitivity from being lowered by the diffusion of heat generated by exposure to the support is also exhibited.

Examples of the compound used for the undercoat layer include polymers having an adsorptive group and a hydrophilic group that can be adsorbed on the surface of the support. In order to improve the adhesion to the image recording layer, a polymer having an adsorptive group and a hydrophilic group and further having a crosslinkable group is preferable. The compound used in the undercoat layer may be a low molecular compound or a polymer. The compound used for the undercoat layer may be used by mixing 2 or more compounds as 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 preferable.

As the adsorptive group which can be adsorbed on the surface of the support, a phenolic hydroxyl group, a carboxyl group and-PO are preferable₃H₂、-OPO₃H₂、-CONHSO₂-、-SO₂NHSO₂-、-COCH₂COCH₃. As the hydrophilic group, a sulfo group or a salt thereof, or a salt of a carboxyl group is preferable. The crosslinkable group is preferably an acrylic group, a methacrylic group, an acrylamide group, a methacrylamide group, an allyl group or the like.

The polymer may have a crosslinkable group introduced by formation of a polar substituent of the polymer, a substituent having a charge opposite to the above-mentioned polar substituent, and a salt of a compound having an ethylenically unsaturated bond, and may further have a monomer other than the above-mentioned monomers, preferably a hydrophilic monomer, copolymerized therein.

Specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group as described in Japanese patent application laid-open No. 10-282679 and a phosphorus compound having an ethylenic double bond reactive group as described in Japanese patent application laid-open No. 2-304441 are preferable. It is also preferable to use a low-molecular or high-molecular compound having a crosslinkable group (preferably an ethylenically unsaturated bond group), a functional group that interacts with the surface of the support, and a hydrophilic group, as described in each of Japanese patent application laid-open Nos. 2005-238816, 2005-125749, 2006-239867, and 2006-215263.

More preferred examples of the compound include an adsorptive group which can be adsorbed on the surface of a support, and a polymer having a hydrophilic group and a crosslinkable group, as described in jp 2005-125749 and jp 2006-188038 a.

The content of the ethylenically unsaturated bond group in the polymer used in the undercoat layer is preferably 0.1 to 10.0mmol, more preferably 0.2 to 5.5mmol, per 1g of the polymer.

The weight average molecular weight (Mw) of the polymer used in the undercoat layer is preferably 5,000 or more, and more preferably 1 to 30 ten thousand.

The undercoat layer may contain, in addition to the compound for undercoat layer, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group or a functional group having a polymerization inhibiting action, and a compound having a group that interacts with the surface of the aluminum support (for example, 1, 4-diazabicyclo [2.2.2] octane ring (DABCO), 2,3,5, 6-tetrahydroxy-p-benzoquinone, chloranil, sulfophthalic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, and the like) in order to prevent contamination with time.

The primer layer can be applied by a known method. The amount of the primer coating (solid content) is preferably 0.1mg/m²～100mg/m²More preferably 1mg/m²～30mg/m²。

< protective layer >

The lithographic printing plate precursor according to the present invention preferably has a protective layer (sometimes also referred to as an overcoat) on the image-recording layer. In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer also has the function of preventing scratches from being generated in the image recording layer and preventing ablation during high-illuminance laser exposure.

Protective layers having such characteristics are described in, for example, U.S. Pat. No.3,458,311 and Japanese patent publication No. 55-049729. As the low oxygen-permeable polymer used for the protective layer, any of a water-soluble polymer and a water-insoluble polymer can be appropriately selected and used, and 2 or more kinds thereof can be mixed and used as necessary. Specific examples thereof include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, and poly (meth) acrylonitrile.

As the modified polyvinyl alcohol, an acid-modified polyvinyl alcohol having a carboxyl group or a sulfo group is preferably used. Specifically, modified polyvinyl alcohols described in Japanese patent application laid-open Nos. 2005-250216 and 2006-259137 are mentioned.

In order to improve the oxygen barrier property, the protective layer preferably contains an inorganic layered compound. Inorganic layered compoundThe particles having a thin plate-like shape include, for example, mica groups such as natural mica and synthetic mica, and particles represented by the formula: 3 MgO.4 SiO.H₂Talc, taeniolite, montmorillonite, saponite, hectorite, zirconium phosphate, etc., represented by O.

The inorganic layered compound preferably used is a mica compound. Examples of the mica compound include compounds represented by the formula: a (B, C)2-5D4O10(OH, F, O)2 [ wherein A is any one of K, Na and Ca, B and C are any one of Fe (II), Fe (III), Mn, Al, Mg and V, and D is Si or Al. Mica groups such as natural mica and synthetic mica.

In the mica group, examples of natural mica include muscovite, paragonite, phlogopite, biotite, and lepidolite. Examples of the synthetic mica include fluorophlogopite KMg₃(AlSi₃O10)F₂Potassium tetrasilicic mica KMg_2.5(Si₄O₁₀)F₂Iso-nonswelling mica and Na-tetrafluoro silicon mica NaMg_2.5(Si₄O₁₀)F₂Na or Li with mica (Na, Li) Mg₂Li(Si₄O₁₀)F₂Montmorillonite series Na or Li hectorite (Na, Li)_1/8Mg_2/5Li_1/8(Si₄O₁₀)F₂And swelling mica. Also synthetic smectites are useful.

Among the mica compounds, fluorine-based swellable mica is particularly useful. That is, the swelling synthetic mica has a thickness ofThe layered structure of the unit lattice layers on the left and right sides has a more significant substitution of metal atoms in the lattice than other clay minerals. As a result, a shortage of positive charge occurs in the lattice layer, and Li is adsorbed between the layers to compensate for the shortage⁺、Na⁺、Ca2⁺、Mg²⁺And the like. These interlayer cations are called exchangeable cations, and can be exchanged with a plurality of cations. In particular, when the cation between the layers is Li⁺、Na⁺When the ionic radius is small, the bonding between the lamellar lattices is weak, andthe swelling is large with water. If shear-inches are applied in this state, the layered crystal lattice is easily cleaved to form a stable sol in water. This tendency of the swellable synthetic mica is strong, and thus it is particularly preferably used.

The shape of the mica compound is preferably as thin as possible from the viewpoint of diffusion control, and the larger the plane size is, the better the smoothness of the coated surface and the transmittance of active light are not hindered. Accordingly, the aspect ratio is preferably 20 or more, more preferably 100 or more, and particularly preferably 200 or more. The aspect ratio is a ratio of the length to the thickness of the particle, and can be measured, for example, by a projection view obtained from a photomicrograph of the particle. The larger the aspect ratio, the greater the effect obtained.

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

The content of the inorganic layered compound is preferably 0 to 60% by mass, and more preferably 3 to 50% by mass, based on the total solid content of the protective layer. When a plurality of inorganic layered compounds are used simultaneously, the total amount of the inorganic layered compounds is also preferably the above amount. Within the above range, the oxygen barrier property is improved and good sensitivity can be obtained. Further, the ink adhesion can be prevented from being lowered.

The protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coatability, and inorganic particles for controlling surface lubricity. The protective layer may contain a fat-sensitive agent described in the image recording layer.

The protective layer is applied by a known method. The coating amount (solid content) of the protective layer is preferably 0.01g/m²～10g/m²More preferably 0.02g/m²～3g/m²Particularly preferably 0.02gm²～1g/m²。

(method for producing planographic printing plate)

The lithographic printing plate precursor of the present invention can be subjected to image exposure and development treatment to produce a lithographic printing plate.

One embodiment of a method for manufacturing a lithographic printing plate according to the present invention sequentially includes: a step of imagewise exposing the lithographic printing plate precursor according to the present invention to form exposed portions and unexposed portions (hereinafter, also referred to as "exposure step"); and a step of supplying at least one of printing ink and fountain solution to remove the unexposed portions (hereinafter, also referred to as an "on-press development step").

Another embodiment of the method for manufacturing a lithographic printing plate according to the present invention includes the steps of: an exposure step of imagewise exposing the lithographic printing plate precursor of the present invention to form exposed portions and unexposed portions; and a step of supplying a developer having a pH of 2 or more and 11 or less to remove the unexposed portions (hereinafter, also referred to as a "developing step").

Hereinafter, preferred embodiments of the respective steps will be described in order with respect to the method for manufacturing a lithographic printing plate according to the present invention and the lithographic printing method according to the present invention. The lithographic printing plate precursor according to the present invention can also be developed with a developer.

< Exposure Process >

The method for producing a lithographic printing plate according to the present invention preferably includes an exposure step of imagewise exposing the lithographic printing plate precursor according to the present invention to form exposed portions and unexposed portions. The lithographic printing plate precursor according to the present invention is preferably subjected to laser exposure through a transparent original image having a line image, a halftone image, or the like, or image-wise exposure through laser beam scanning or the like based on digital data.

A light source having a wavelength of 750nm to 1,400nm is preferably used. As the light source of 750nm to 1,400nm, solid lasers and semiconductor lasers radiating infrared rays are preferable. The infrared laser preferably has an output of 100mW or more and is exposed to light per 1 pixelThe time is preferably within 20 microseconds, and the irradiation energy is preferably 10mJ/cm²～300mJ/cm². Also, in order to shorten the exposure time, a multi-beam laser apparatus is preferably used. The exposure mechanism may be any of an inner drum system, an outer drum system, a flat plate system, and the like.

The image exposure can be performed by a conventional method using a plate-making machine or the like. In the case of on-press development, image exposure may be performed on a printing press after the lithographic printing plate precursor is mounted on the printing press.

< on-machine development step and development step >

The method of manufacturing a lithographic printing plate according to the present invention preferably includes an on-press development step of supplying at least one of a printing ink and a fountain solution to remove the unexposed portion.

The method of manufacturing the lithographic printing plate according to the present invention can be performed by a method of developing with a developer (developer processing method).

For example, the method of manufacturing a lithographic printing plate according to the present invention includes a developing step of supplying a developer having a pH of 2 or more and 11 or less to remove the unexposed portions.

Hereinafter, an on-machine development method will be described.

On-machine development mode

In the on-press development method, the lithographic printing plate precursor subjected to image exposure is preferably produced by supplying an oil-based ink and an aqueous component onto a printing press and removing the image-forming layer in the non-image portion.

That is, when the lithographic printing plate precursor is directly mounted on a printing press without any development treatment after image exposure, or when the lithographic printing plate precursor is mounted on the printing press and then image exposure is performed on the printing press, and then the oil-based ink and the aqueous component are supplied and printing is performed, in an initial stage during printing, the image-forming layer that is not cured by either or both of the supplied oil-based ink and the aqueous component is dissolved or dispersed and removed in the non-image portion, and the hydrophilic surface is exposed to the portion. On the other hand, in the exposure portion, the image forming layer cured by exposure forms an oil-based ink receiving portion having an oleophilic surface. The compound to be initially supplied to the printing surface may be an oil-based ink or an aqueous component, but the oil-based ink is preferably initially supplied from the viewpoint of preventing contamination due to the components of the image forming layer from which the aqueous component has been removed. In this way, the lithographic printing plate precursor is subjected to on-press development on a printing press and is directly used for printing a plurality of sheets. As the oil-based ink and the aqueous component, a general lithographic printing ink and a fountain solution can be preferably used.

As the laser light for image-wise exposing the lithographic printing plate precursor of the present invention containing the above polymerization initiator and polymerizable compound, the wavelength of the light source is preferably 300nm to 450nm or 750nm to 1,400 nm. In the case of a light source of 300nm to 450nm, a lithographic printing plate precursor containing a sensitizing dye having an absorption maximum in the wavelength region in the image recording layer is preferably used, and the above light source is preferably used as a light source of 750 to 1,400 nm. As the light source of 300nm to 450nm, a semiconductor laser is preferable.

Processing of the developing solution

The lithographic printing plate precursor according to the present invention can be used to produce a lithographic printing plate by a developing treatment using a developer, with an appropriate selection of a binder polymer or the like as a constituent of the image-recording layer. The developing treatment using a developer includes a method of using a developer which can contain at least 1 compound selected from the group consisting of surfactants and water-soluble polymer compounds and has a pH of about 2 to 11 (also referred to as a simple developing treatment).

The developing solution contains a water-soluble polymer compound as necessary, and thus the developing and gum solution treatment steps can be performed simultaneously. Therefore, particularly, the post-washing step is not required, and the drying step can be performed after the development and the gum solution treatment in the 1-liquid-1 step. Accordingly, the development treatment using the developer is preferably a method for producing a lithographic printing plate including a step of developing the image-exposed lithographic printing plate precursor with a developer having a pH of 2 to 11. After the development treatment, it is preferable to perform drying after removing the remaining developer using a squeegee roller.

That is, in the developing step of the method for manufacturing a lithographic printing plate according to the present invention, it is preferable to perform the developing treatment and the gum solution treatment in the 1-liquid-1 step.

The developing and gum solution treatment by the 1-liquid-1 process means that the developing treatment and gum solution treatment are performed by the 1-liquid-1 process, and the developing treatment and gum solution treatment are not performed as separate processes.

The developing process can be preferably performed by an automatic developing processor including a supply mechanism of the developer and a friction member. As the rubbing member, an automatic developing processor using a rotating brush roller is particularly preferable.

The number of the rotating brush rolls is preferably 2 or more. The automatic development processor preferably includes a mechanism for removing excess developer such as a squeegee roller or a drying mechanism such as a heater after the development processing mechanism. The automatic development processor preferably includes a pre-heating mechanism for performing a heating process on the lithographic printing plate precursor after the image exposure, before the development processing mechanism.

The processing by such an automatic development processor has an advantage that it can be released from the corresponding release of development residues originating from the protective layer/image recording layer, which is generated in the case of the so-called on-press development processing.

In the case of a manual process in the developing step, a preferred method of the developing process is, for example, a method in which an aqueous solution is contained in sponge or cotton wool, the entire surface of the plate is wiped while the treatment is performed, and the plate is dried after the completion of the treatment. In the case of the dipping treatment, for example, a method of dipping the lithographic printing plate precursor in a vat or a deep tank containing an aqueous solution for about 60 seconds and stirring, and then drying while wiping with absorbent cotton or sponge or the like is preferable.

In the developing treatment, an apparatus having a simplified structure and simplified steps is preferably used.

In the alkali development treatment, the protective layer is removed by a pre-washing step, followed by development with a high-pH alkaline developer, followed by alkali removal by a post-washing step, glue treatment by a glue application step, and drying by a drying step. In the simple development treatment, development and gumming can be simultaneously performed with 1 liquid. Therefore, the post-washing step and the gum treatment step can be omitted, and it is preferable to perform the drying step as needed after performing development and gumming (gum solution treatment) with the solution 1.

It is preferable that the removal of the protective layer, the development and the application of the adhesive are performed simultaneously with the solution 1 without performing the pre-washing step. After the development and the coating, it is preferable to remove the remaining developer using a squeegee roller and then dry the developer.

In the developing step, the developer may be immersed in the developer 1 time or immersed in the developer 2 or more times. Among them, the method of immersing in the above-mentioned developer 1 or 2 times is preferable.

The immersion may be performed by drilling the exposed lithographic printing plate precursor into a developer tank in which a developer is stored, or by spraying the developer onto the plate surface of the exposed lithographic printing plate precursor with a sprayer or the like.

In addition, even in the case of immersing in the developer for 2 times or more, when the same developer or a developer (fatigue liquid) in which the developer and a component of the image recording layer are dissolved or dispersed by the development treatment are immersed for 2 times or more, it is referred to as the development treatment (1-liquid treatment) with 1 liquid.

In the developing treatment, a rubbing member is preferably used, and a rubbing member such as a brush is preferably provided in the developing bath for removing the non-image portion of the image recording layer.

The development treatment can be carried out according to a conventional method, and by preferably immersing the lithographic printing plate precursor subjected to the exposure treatment in a developer and rubbing with a brush or sucking a treatment liquid injected into an external tank with a pump, for example, and spraying from a sprayer nozzle and rubbing with a brush, at a temperature of 0 to 60 ℃, more preferably at a temperature of 15 to 40 ℃. These development treatments can also be carried out a plurality of times in succession. For example, the treatment can be performed by pumping the treatment liquid injected into an external tank, spraying the treatment liquid from the sprayer nozzle, rubbing the treatment liquid with a brush, and then spraying the treatment liquid from the sprayer nozzle again, rubbing the treatment liquid with a brush. When the developing process is performed using an automatic developing machine, the developer is fatigued in accordance with an increase in the amount of the process, and therefore, it is preferable to recover the processing ability using a replenishing liquid or a fresh developer.

In the development process, a paste coater or an automatic developing machine known as a PS Plate (Presensitized Plate) or a CTP (Computer to Plate) can be used. When an automatic developing machine is used, any of a system in which a developer injected into a developing tank or a developer injected into an external tank is pumped by a pump and sprayed from a sprayer nozzle to perform a process, a system in which a printing plate is immersed and conveyed by an in-liquid guide roller or the like in a tank filled with the developer to perform a process, and a so-called one-shot process system in which a developer that is not substantially used is supplied to each plate in a required amount to perform a process can be applied. In either case, a scrubbing mechanism based on brushes or double-sided pile is more preferred. For example, commercially available automatic developing machines (Clean Out Unit C85/C125, Clean-Out Unit + C85/120, FCF 85V, FCF 125V, FCF News (Glunz & Jensen), Azura CX85, Azura CX125, and Azura CX150(AGFA GRAPHICS) can be used, and a device in which a laser exposure section and an automatic developing machine section are integrally assembled can also be used.

Hereinafter, the components of the developing solution used in the developing step and the like will be described in detail.

〔pH〕

The pH of the developer is preferably 2 to 11, more preferably 5 to 9, and further preferably 7 to 9. From the viewpoint of developability or dispersibility of the image recording layer, it is advantageous to set the pH value high, but with respect to printability, particularly suppression of staining, it is effective to set the pH value low.

Here, the pH was measured at 25 ℃ using a pH meter (model: HM-31, manufactured by DKK-TOA CORPORATION).

[ surfactant ]

The developer may contain a surfactant such as an anionic surfactant, a nonionic surfactant, a cationic surfactant, or an amphoteric surfactant.

From the viewpoint of brush staining properties, the developer preferably contains at least 1 selected from the group consisting of anionic surfactants and amphoteric surfactants.

The developer preferably contains a nonionic surfactant, and more preferably contains at least 1 selected from the group consisting of a nonionic surfactant, an anionic surfactant, and an amphoteric surfactant.

Preferred examples of the anionic surfactant include compounds represented by the following formula (I).

R¹-Y¹-X¹(I)

In the formula (I), R¹Represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group which may have a substituent.

The alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, a decyl group, a dodecyl group, a hexadecyl group, and an octadecyl group.

The cycloalkyl group may be monocyclic or polycyclic. The monocyclic ring is preferably a monocyclic cycloalkyl group having 3 to 8 carbon atoms, and more preferably a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, or a cyclooctyl group. Examples of the polycyclic group include an adamantyl group, a norbornyl group, an isobornyl group, a camphyl group, a dicyclopentyl group, an α -sulfoenyl group, and a tricyclodecanyl group.

The alkenyl group is preferably an alkenyl group having 2 to 20 carbon atoms, and specific examples thereof include a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group.

The aralkyl group is preferably an aralkyl group having 7 to 12 carbon atoms, and specifically, a benzyl group, a phenethyl group, a naphthylmethyl group, and the like can be preferably mentioned.

The aryl group is preferably an aryl group having 6 to 15 carbon atoms, and specific examples thereof include a phenyl group, a tolyl group, a dimethylphenyl group, a 2,4, 6-trimethylphenyl group, a naphthyl group, an anthryl group, a 9, 10-dimethoxyanthryl group and the like.

As the substituent, a monovalent nonmetallic atom group other than a hydrogen atom can be used, and preferable examples thereof include a halogen atom (F, Cl, Br, or I), a hydroxyl group, an alkoxy group, an aryloxy group, an acyl group, an amide group, an ester group, an acyloxy group, a carboxyl group, a carboxylic acid anion group, a sulfonic acid anion group, and the like.

Specific examples of the alkoxy group in the substituent include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a pentoxy group, a hexoxy group, a dodecoxy group, a stearyloxy group, a methoxyethoxy group, a poly (ethyleneoxy) group, a poly (propyleneoxy) group, and the like, preferably an alkoxy group having 1 to 40 carbon atoms, and more preferably an alkoxy group having 1 to 20 carbon atoms. Examples of the aryloxy group include aryloxy groups having 6 to 18 carbon atoms such as a phenoxy group, a tolyloxy group, a xylyloxy group, a mesityloxy group, a cumene oxy group, a methoxyphenoxy group, an ethoxyphenoxy group, a chlorophenoxy group, a bromophenoxy group, and a naphthyloxy group. Examples of the acyl group include acyl groups having 2 to 24 carbon atoms such as an acetyl group, a propionyl group, a butyryl group, a benzoyl group, and a naphthoyl group. Examples of the amide group include amide groups having 2 to 24 carbon atoms such as an acetamide group, a propionate amide group, a dodecanoic acid amide group, a palmitic acid amide group, a stearic acid amide group, a benzoic acid amide group, and a naphthoic acid amide group. Examples of the acyloxy group include acyloxy groups having 2 to 20 carbon atoms such as an acetoxy group, a propionyloxy group, a benzoyloxy group, and a naphthoyloxy group. Examples of the ester group include ester groups having 1 to 24 carbon atoms such as a methyl ester group, an ethyl ester group, a propyl ester group, a hexyl ester group, an octyl ester group, a dodecyl ester group, and an octadecyl ester group. The substituent may be composed of a combination of 2 or more of the above substituents.

X¹Represents a sulfonate group, a sulfate monoester group, a carboxylate group or a phosphate group.

Y¹Represents a single bond, -C_nH_2n-、-C_n-mH_2(n-m)OC_mH_2m-、-O-(CH₂CH₂O)_n-、-O-{CH₂CH(CH₃)O}_n-、-O-{CH(CH₃)CH₂O}_n-、-O-(CH₂CH₂CH₂O)_n-, -CO-NH-or a 2-valent linking group comprising 2 or more combinations thereof, and satisfies n.gtoreq.1 and n.gtoreq.m.gtoreq.0.

Among the compounds represented by the formula (I), compounds represented by the following formula (I-A) or formula (I-B) are preferable from the viewpoint of scratch contamination resistance.

[ chemical formula 21]

In the formulae (I-A) and (I-B), R^A1～R^A10Each independently represents a hydrogen atom or an alkyl group, nA represents an integer of 1 to 3, X^A1And X^A2Each independently represents a sulfonate group, a sulfate monoester group, a carboxylate group or a phosphate group, Y^A1And Y^A2Each independently represents a single bond, -CnH_2n-、-C_n-mH_2(n-m)OC_mH_2m-、-O-(CH₂CH₂O)_n-、-O-{CH₂CH(CH₃)O}_n-、-O-{CH(CH₃)CH₂O}_n-、-O-(CH₂CH₂CH₂O)_n-, -CO-NH-or a 2-valent linking group comprising 2 or more combinations thereof, and satisfies n.gtoreq.1 and n.gtoreq.m.gtoreq.0, R^A1～R^A5Or R^A6～R^A10Neutralization of Y^A1Or Y^A2The total number of carbon atoms in (2) is 3 or more.

R in the compound represented by the above formula (I-A) or formula (I-B)^A1～R^A5And Y^1AOr, R^A6～R^A10And Y^A2The total carbon number of (2) is preferably 25 or less, more preferably 4 to 20. The structure of the alkyl group may be a straight chain or a branched chain.

X in the compound represented by the formula (I-A) or the formula (I-B)^A1And X^A2Preferably sulfonate or carboxylate groups. And, X^A1And X^A2Among the salt structures in (b), alkali metal salts are preferable because they are particularly excellent in solubility in aqueous solvents. Among them, sodium salt or potassium salt is particularly preferable.

As the compounds represented by the above formula (I-A) or formula (I-B), reference can be made to the description in paragraphs 0019 to 0037 of Japanese patent laid-open publication No. 2007-206348.

As the anionic surfactant, the compounds described in paragraphs 0023 to 0028 of Japanese patent application laid-open No. 2006-065321 can also be preferably used.

The amphoteric surfactant used in the developer is not particularly limited, and examples thereof include amine oxide systems such as alkyldimethylamine oxide, betaine systems such as alkylbetaine, fatty acid amide propylbetaine, and alkylimidazole, and amino acid systems such as sodium alkylaminohydrofate.

In particular, alkyldimethylamine oxides which may have substituents, alkylcarboxybetaines which may have substituents, and alkylsulfobetaines which may have substituents can be preferably used. Specific examples thereof include compounds represented by the formula (2) in paragraph 0256 of jp 2008-one 203359, compounds represented by the formulae (I), (II) and (VI) in paragraph 0028 of jp 2008-one 276166, and compounds described in paragraphs 0022 to 0029 of jp 2009-one 047927.

The zwitterionic surfactant used in the developer is preferably a compound represented by the following general formula (1) or a compound represented by the general formula (2).

[ chemical formula 22]

In the general formulae (1) and (2), R¹And R¹¹Each independently represents an alkyl group having 8 to 20 carbon atoms or an alkyl group having a linking group having 8 to 20 carbon atoms in total.

R²、R³、R¹²And R¹³Each independently represents a hydrogen atom, an alkyl group or a group having an oxirane structure.

R⁴And R¹⁴Each independently represents a single bond or an alkylene group.

And, R¹、R²、R³And R⁴2 groups in (A) may beAre bonded to each other to form a ring structure, R¹¹、R¹²、R¹³And R¹⁴2 groups in (a) may be bonded to each other to form a ring structure.

In the compound represented by the general formula (1) or the compound represented by the general formula (2), the hydrophobic portion becomes large as the total carbon number becomes large, and the solubility of the aqueous system in the developer decreases. In this case, the solubility is optimized by mixing an organic solvent such as an alcohol which assists dissolution as a dissolution aid in water, but if the total carbon number is excessively increased, the surfactant cannot be dissolved in an appropriate mixing range. Thus, R¹～R⁴Or R¹¹～R¹⁴The total number of carbon atoms of (a) is preferably 10 to 40, more preferably 12 to 30.

From R¹Or R¹¹The alkyl group having a linking group represented represents a structure having a linking group between alkyl groups. That is, when the number of the linker is 1, it can be represented by "-alkylene-linker-alkyl". Examples of the linker include an ester bond, a carbonyl bond, and an amide bond. The number of the linker may be 2 or more, but is preferably 1, and particularly preferably an amide bond. The total number of carbon atoms of the alkylene group bonded to the linking group is preferably 1 to 5. The alkylene group may be linear or branched, but is preferably a linear alkylene group. The alkyl group bonded to the linker preferably has 3 to 19 carbon atoms, and may be a straight chain or branched chain, but is preferably a straight chain alkyl group.

When R is²Or R¹²In the case of an alkyl group, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. May be any 1 of linear chain and branched chain, but is preferably linear chain.

When R is³Or R¹³In the case of an alkyl group, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. May be any 1 of linear chain and branched chain, but is preferably linear chain.

As a group consisting of R³Or R¹³Examples of the group having an oxirane structure include a group represented by the formula-R^a(CH₂CH₂O)_nR^bThe group shown. Wherein R is^aRepresents a single bond, an oxygen atom or a 2-valent organic group (preferably having 10 carbon atoms or more)Lower), R^bRepresents a hydrogen atom or an organic group (preferably, a carbon number of 10 or less), and n represents an integer of 1 to 10.

When R is⁴And R¹⁴In the case of an alkylene group, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. May be any 1 of linear chain and branched chain, but is preferably linear chain.

The compound represented by the general formula (1) or the compound represented by the general formula (2) preferably has an amide bond as R¹Or R¹¹The linker of (3) more preferably has an amide bond.

Hereinafter, representative examples of the compound represented by the general formula (1) or the compound represented by the general formula (2) will be described, but the present invention is not limited to these.

[ chemical formula 23]

[ chemical formula 24]

[ chemical formula 25]

The compound represented by the general formula (1) or (2) can be synthesized by a known method. Further, commercially available compounds can also be used. As commercially available products, the compounds represented by the general formula (1) include Kawaken Fine Chemicals Co., Ltd, SOFTAZ0LINE LPB manufactured by Ltd, SOFTAZ0LINE LPB-R, vista MAP, TAKEMOTO OIL & FAT Co., Ltd, Takesafu C-157L manufactured by Ltd, and the like. Examples of the compound represented by the general formula (2) include Kawaken Fine Chemicals Co., Ltd., SoftAZ0LINE LAO manufactured by Ltd., DAI-ICHI KOGYO SEIYAKU CO., LTD AMOGEN AOL manufactured by LTD.

The zwitterionic surfactant may be used alone in an amount of 1 kind or in combination with 2 or more kinds in the developer.

Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyrene phenyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, neopentyl glycol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerol fatty acid partial esters, polyoxyethylene glycerin fatty acid partial esters, polyoxyethylene diglycols, fatty acid diethanolamides, N, n-bis-2-hydroxyalkylamines, polyoxyethylenealkylamines, triethanolamine fatty acid esters, trialkylammonium oxides, polyoxyethylenealkylphenyl ethers, polyoxyethylene-polyoxypropylene block copolymers, and the like.

In addition, surfactants such as acetylene glycol-based and acetylene alcohol-based ethylene oxide adducts and fluorine-based surfactants can be used in the same manner. These surfactants can be used in combination of 2 or more.

The nonionic surfactant is preferably a nonionic aromatic ether surfactant represented by the following formula (N1).

X^N-Y^N-O-(A¹)_nB-(A²)_mB-H (N1)

In the formula, X^NRepresents an aromatic group which may have a substituent, Y^NRepresents a single bond or an alkylene group having 1 to 10 carbon atoms, A¹And A²Are mutually different radicals and represent-CH₂CH₂O-or-CH₂CH(CH₃) Any one of O-, nB and mB independently represents an integer of 0 to 100, wherein nB and mB are not 0 at the same time, and nB and mB are not 1 when nB and mB are 0.

In the formula, as X^NExamples of the aromatic group of (2) include a phenyl group, a naphthyl group, and an anthryl group. These aromatic groups may have a substituent. Examples of the substituent include an organic group having 1 to 100 carbon atoms. In the formula, A and B may be random or block copolymers when both are present.

Specific examples of the organic group having 1 to 100 carbon atoms include saturated or unsaturated, straight or branched aliphatic or aromatic hydrocarbon groups, and examples thereof include alkyl, alkenyl, alkynyl, aryl, aralkyl groups, and other examples include alkoxy, aryloxy, N-alkylamino, N-dialkylamino, N-arylamino, N-diarylamino, N-alkyl-N-arylamino, acyloxy, carbamoyloxy, N-alkylcarbamoyloxy, N-arylcarbamoyloxy, N-dialkylcarbamoyloxy, N-diarylcarbamoyloxy, N-alkyl-N-arylcarbamoyloxy, acylamino, N-alkylamido, N-arylamido, N-arylamido, acyl, alkoxycarbonylamino, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, N-alkylcarbamoyl, N-dialkylcarbamoyl, N-arylcarbamoyl, N-diarylcarbamoyl, N-alkyl-N-arylcarbamoyl, the above-mentioned organic group bonded to a polyoxyalkylene chain, polyoxyalkylene chain or the like. The alkyl group may be a straight chain or a branched chain.

Further, as the nonionic surfactant, the compounds described in paragraphs 0030 to 0040 of Japanese patent application laid-open No. 2006-065321 can also be preferably used.

The cationic surfactant is not particularly limited, and conventionally known surfactants can be used. For example, alkylamine salts, quaternary ammonium salts, alkylimidazolidium salts, polyoxyethylene alkylamine salts, polyethylene polyamine derivatives, and the like can be mentioned.

The surfactant may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The content of the surfactant is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, still more preferably 3 to 15% by mass, and particularly preferably 5 to 10% by mass, based on the total mass of the developer. When the amount is within the above range, the ink composition is further excellent in scratch stain resistance, the dispersibility of the development residue is excellent, and the obtained lithographic printing plate is excellent in ink receptivity.

[ Water-soluble Polymer ]

The developer can contain a water-soluble polymer from the viewpoint of adjusting the viscosity of the developer and protecting the plate surface of the obtained lithographic printing plate.

Examples of the water-soluble polymer include water-soluble polymer compounds such as soybean polysaccharides, modified starch, gum arabic, dextrin, cellulose derivatives (e.g., carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol and derivatives thereof, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymers, vinyl methyl ether/maleic anhydride copolymers, vinyl acetate/maleic anhydride copolymers, and styrene/maleic anhydride copolymers.

Conventionally known soybean polysaccharides can be used as the soybean polysaccharides, and for example, Soyafibe (FUJI OIL co., ltd) is a commercially available product, and various grades of soybean polysaccharides can be used. The viscosity of a10 mass% aqueous solution of a substance that can be used is preferably in the range of 10 mPas to 100 mPas.

The modified starch is preferably a starch represented by the following formula (III). As the starch represented by formula (III), any 1 kind of starch of corn, potato, tapioca, rice, wheat, and the like can also be used. The starch can be modified by a method of decomposing the starch with an acid, an enzyme or the like within a range of 5 to 30 glucose residues per 1 molecule, and further adding propylene oxide to an alkali.

[ chemical formula 26]

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

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

The water-soluble polymer compound can be used in combination of 2 or more.

When the developer contains a water-soluble polymer compound, the content of the water-soluble polymer compound is preferably 3% by mass or less, and more preferably 1% by mass or less, based on the total mass of the developer. In this manner, the viscosity of the developer is appropriate, and accumulation of development residue and the like on the roller member of the automatic developing machine can be suppressed.

[ other additives ]

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

As the humectant, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, diglycerin, and the like can be preferably used. The humectant can be used alone or in combination of 2 or more. The content of the wetting agent is preferably 0.1 to 5% by mass with respect to the total mass of the developer.

Examples of the preservative include phenol or a derivative thereof, formalin, an imidazole derivative, sodium dehydroacetate, a 4-isothiazolin-3-one derivative, benzisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, a benzotriazole derivative, an amidinobuanidine derivative, a quaternary ammonium salt, a derivative such as pyridine, quinoline or guanidine, a diazine, a triazole derivative, oxazole or oxazine derivative, a nitro bromohydrin type 2-bromo-2-nitropropane-1, 3-diol, 1-dibromo-1-nitro-2-ethanol, and 1, 1-dibromo-1-nitro-2-propanol.

The amount of the preservative added is an amount that stably exerts its effect on bacteria, molds, yeasts, and the like, and varies depending on the types of bacteria, molds, and yeasts, but is preferably in the range of 0.01 to 4 mass% with respect to the total mass of the developer. It is also preferable to use 2 or more kinds of preservatives together so as to have an effect on various kinds of mold and sterilization.

Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salts thereof, and sodium salts thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetramine hexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediamine triacetic acid, potassium salt thereof, sodium salt thereof; nitrilotriacetic acid, its sodium salt; 1-hydroxyethane-1, 1-diphosphonic acid, potassium salts thereof, sodium salts thereof; and organic phosphonic acids such as aminotri (methylenephosphonic acid), potassium salts thereof, and sodium salts thereof. Instead of the sodium and potassium salts of the chelating agent, organic amine salts are also effective.

The chelating agent is preferably present stably in the composition of the treatment liquid and does not inhibit printability. The content of the chelating agent is preferably 0.001 to 1.0 mass% based on the total mass of the developer.

As the defoaming agent, a compound having an HLB (Hydrophilic-Lipophilic Balance) of 5 or less such as a general silicone self-emulsifying type, an emulsifying type, and a nonionic type can be used. Silicone-based antifoaming agents are preferred.

In addition, silicone surfactants are considered to be defoaming agents.

The content of the defoaming agent is preferably in the range of 0.001 to 1.0 mass% with respect to the total mass of the developer.

Examples of the organic acid include citric acid, acetic acid, oxalic acid, malonic acid, salicylic acid, octanoic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organophosphonic acid. The organic acid may be used in the form of an alkali metal salt or an ammonium salt thereof. The content of the organic acid is preferably 0.01 to 0.5% by mass based on the total mass of the developer.

Examples of the organic solvent include aliphatic hydrocarbons (hexane, heptane, "ISOPAR E, ISOPAR H, ISOPAR" (Esso Chemical co., ltd., etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated hydrocarbons (dichloromethane, dichloroethane, trichloroethylene, monochlorobenzene, etc.), polar solvents, and the like.

Examples of the polar solvent include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl methanol, n-amyl alcohol, methyl amyl alcohol, etc.), ketones (acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.), and others (triethyl phosphate, triethyl ester, triethyl propionate, etc.) Tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).

When the organic solvent is insoluble in water, it can be used by dissolving it in water using a surfactant or the like, and when the developer contains an organic solvent, the concentration of the solvent in the developer is preferably less than 40% by mass from the viewpoint of safety and flammability.

Examples of the inorganic acid and inorganic salt include phosphoric acid, metaphosphoric acid, monoammonium phosphate, diammonium phosphate, monosodium phosphate, disodium phosphate, monopotassium phosphate, dipotassium phosphate, sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogensulfate, and nickel sulfate. The content of the inorganic salt is preferably 0.01 to 0.5 mass% with respect to the total mass of the developer.

The developer can be prepared by dissolving or dispersing the above-mentioned respective components in water as required. The solid content concentration of the developer is preferably 2 to 25% by mass. As the developer, a concentrated solution can be prepared and used by diluting with water at the time of use.

The developer is preferably an aqueous developer.

The developer preferably contains an alcohol compound from the viewpoint of dispersibility of the development residue.

Examples of the alcohol compound include methanol, ethanol, propanol, isopropanol, and benzyl alcohol. Among them, benzyl alcohol is preferable.

The content of the alcohol compound is preferably 0.01 to 5% by mass, more preferably 0.1 to 2% by mass, and particularly preferably 0.2 to 1% by mass, based on the total mass of the developer, from the viewpoint of dispersibility of the development residue.

< printing Process >

The lithographic printing method according to the present invention includes a printing step of supplying printing ink to the lithographic printing plate developed in the on-press development step or the development step and printing a recording medium.

The printing ink is not particularly limited, and various known inks can be used as needed. Further, as the printing ink, oil-based ink or ultraviolet curable ink (UV ink) is preferable, and UV ink is more preferable.

In the printing step, a fountain solution may be supplied as needed.

Further, the printing step may be continuously performed in the on-press developing step without stopping the printing press.

The recording medium is not particularly limited, and a known recording medium can be used as needed.

In the method for producing a lithographic printing plate from the lithographic printing plate precursor according to the present invention and the lithographic printing method according to the present invention, the entire surface of the lithographic printing plate precursor may be heated before exposure, during exposure, or during exposure to development, as necessary. Such heating can promote an image forming reaction in the image forming layer, and can provide advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity. The heating before development is preferably performed under mild conditions of 150 ℃ or lower. In this way, problems such as curing of the non-image portion can be prevented. For heating after development, it is preferable to use very strong conditions, preferably in the range of 100 ℃ to 500 ℃. Within the above range, a sufficient image-strengthening effect can be obtained, and problems such as deterioration of the support and thermal decomposition of the image portion can be suppressed.

(resin composition for lithographic printing original plate production)

The resin composition for lithographic printing plate precursor production according to the present invention has a solubility parameter of 20MPa^1/2A polymer of the above-mentioned monomer constituent unit, an infrared absorber, and polymer particles.

The resin composition for producing a lithographic printing plate precursor according to the present invention can be preferably used for forming an image-recording layer in the lithographic printing plate precursor according to the present invention.

Further, the resin composition for producing a lithographic printing plate precursor according to the present invention preferably further contains a polymerization initiator and a polymerizable compound. In the above aspect, the photosensitive resin composition can be preferably used as a negative photosensitive resin composition.

The resin composition for lithographic printing plate precursor production according to the present invention has a solubility parameter of 20MPa^1/2The polymer, the infrared absorber, the polymer particles, the polymerizable compound, and the polymerization initiator of the constituent unit of the monomer described above have the same meanings as those of the infrared absorber, the polymerizable compound, and the polymerization initiator contained in the image recording layer of the lithographic printing plate precursor, respectively, and preferred embodiments thereof are also the same.

The resin composition for producing a lithographic printing plate precursor according to the present invention may further contain at least 1 selected from the group consisting of a radical generation aid, a chain transfer agent, a low-molecular hydrophilic compound, a fat-sensitive agent, an acid developer, and a known solvent.

The content of each component contained in the resin composition for producing a lithographic printing plate precursor according to the present invention corresponds to an amount obtained by replacing the content of each component contained in the image recording layer of the lithographic printing plate precursor with a solid content in the resin composition for producing a lithographic printing plate precursor.