WO2019146769A1

WO2019146769A1 - Lithographic printing plate original plate, and method for producing lithographic printing plate

Info

Publication number: WO2019146769A1
Application number: PCT/JP2019/002582
Authority: WO
Inventors: 修史平野; 洋平石地; 和朗榎本; 啓介野越; 藤田　明徳
Original assignee: 富士フイルム株式会社
Priority date: 2018-01-29
Filing date: 2019-01-25
Publication date: 2019-08-01

Abstract

Provided are: a lithographic printing plate original plate which comprises an aluminum support body and an image recording layer formed on the aluminum support body, and in which the total content of halide ions with respect to the total mass of all layers formed on the aluminum support body is more than 0 ppm and less than or equal to 1,000 ppm; and a method for producing a lithographic printing plate in which the lithographic printing plate original plate is used.

Description

Lithographic printing plate precursor and method of preparing lithographic printing plate

The present disclosure relates to a lithographic printing plate precursor and a method of preparing a lithographic printing plate.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink during the printing process and a hydrophilic non-image area that receives dampening water. In lithographic printing, utilizing the property that water and oil-based ink repel each other, the lipophilic image area of the lithographic printing plate is an ink receiving area, and the hydrophilic non-image area is a dampening water receiving area (ink non-receiving area). This is a method in which a difference in the adhesivity of the ink is produced on the surface of the lithographic printing plate, the ink is deposited only in the image area, and then the ink is transferred to a printing material such as paper for printing.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which a lipophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has hitherto been widely used. Usually, after exposing a lithographic printing plate precursor through an original such as a lith film, a portion to be an image portion of the image recording layer is left, and the unnecessary image recording layer is treated with an alkaline developer or an organic solvent. A lithographic printing plate is obtained by plate-making by a method of dissolving and removing with a solvent, exposing the hydrophilic support surface and forming a non-image area.

In addition, environmental issues related to liquid waste associated with wet processing such as development processing have been highlighted from the growing interest in the global environment.
For the above-mentioned environmental problems, simplification or non-processing of development or plate making is directed. As one of the simple production methods, a method called "on-press development" is performed. That is, after exposing the lithographic printing plate precursor, conventional development is not performed, and the lithographic printing plate precursor is mounted on a printing machine as it is, and removal of the unnecessary portion of the image recording layer is performed at the initial stage of the ordinary printing process.
Examples of a printing method using a conventional lithographic printing plate precursor or a lithographic printing plate precursor include those described in Patent Documents 1 and 2.

JP-A-2017-154318 has at least one constituent layer on an aluminum support mounted on the same plate cylinder of a printing machine, and at least one of the constituent layers has a low molecular weight hydrophilic compound. A step of on-press developing an on-press development type lithographic printing plate precursor having an on-press developable planographic printing plate dummy plate, and an image recording layer containing a polymerization initiator containing an organic boron-containing anion on an aluminum support Printing methods are described.
Japanese Patent Application Laid-Open No. 2007-045144 has an image recording layer which can be drawn by infrared laser exposure on a support, and is mounted on a printing machine without undergoing a development treatment step after image recording, or a printing machine It is a lithographic printing plate precursor which can be printed by recording an image after mounting, and the image recording layer contains (A) an infrared absorber and (B) an iodonium salt represented by the following formula (1). A lithographic printing plate precursor is described.

In formula (1),
Ar ₁ and Ar ₂ each represent a benzene ring which may have a substituent, wherein the substituents of the two benzene rings are different from each other, and the sum of the Hammett σ values of the substituents of at least one of the benzene rings Represents a structure where is negative.
Z represents a counter anion.

When the layer formed on the aluminum support in the lithographic printing plate precursor contains a halide ion, corrosion of a small area may occur in the aluminum support during storage of the lithographic printing plate precursor. Thus, when corrosion occurs in the non-image area of the lithographic printing plate precursor, removal of the image recording layer by development is insufficient in the corroded area due to the formation of a polymer around the corroded area, etc. It may be As a result, in the obtained lithographic printing plate, a residual film having a small area such as a dot shape may be generated in the non-image area.
When printing is performed using a lithographic printing plate in which such a residual film is generated, the ink adheres to the residual film, and the printed matter obtained has a small area such as a dot shape or a ring shape (for example, a diameter of 20 μm to In some cases, printing stains of 2,000 μm or the like (hereinafter, also referred to as “Spot Scumming”) may occur.
When a layer such as an image recording layer is formed on an aluminum support by coating the composition in the production of a lithographic printing plate precursor, precipitates such as salts are deposited on the coated surface to cause coating unevenness. The surface condition of the surface of the lithographic printing plate precursor may be lowered.

Problems to be solved by the embodiments of the present disclosure include a planographic printing plate precursor which suppresses the occurrence of a pot-like stain and has an excellent surface appearance, and a planographic printing plate using the above planographic printing plate precursor. It is to provide a plate making method.

Means for solving the above problems include the following aspects.
<1> The total content of halide ions relative to the total mass of all the layers formed on the above aluminum support, including the aluminum support and the image recording layer formed on the above aluminum support, A lithographic printing plate precursor having more than 0 ppm and no more than 1,000 ppm.
<2> The lithographic printing plate precursor as described in <1>, wherein the total content of the halide ion is more than 0 ppm and not more than 500 ppm.
<3> The layer selected from the group consisting of a fluoride ion, a chloride ion, a bromide ion, and an iodide ion as the halide ion in any layer among all the layers formed on the aluminum support The lithographic printing plate precursor as described in <1> or <2> above, which comprises at least one selected from the group consisting of
<4> The lithographic printing plate precursor as described in any one of <1> to <3> above, wherein any layer formed on the aluminum support contains a halide of a quaternary ammonium cation.
<5> The image recording layer contains an electron accepting polymerization initiator,
The lithographic printing plate precursor as described in any one of the above <1> to <4>, wherein the electron accepting polymerization initiator is an iodonium salt.
<6> The lithographic printing plate precursor as described in <5> above, wherein the iodonium salt is a compound represented by the following formula 1.

In Formula 1, Ar ¹ and Ar ² are benzene rings which may have a substituent, and the substituents of two benzene rings are different from each other, and at least one of the substituents of the benzene ring is A structure in which the sum of Hammett σ values is negative, Z ⁻ represents a counter anion.
<7> The lithographic printing plate precursor as described in <5> or <6> above, wherein the iodonium salt is a compound represented by the following formula 1a.

In Formula 1a, Ar ^1a is a benzene ring having a substituent, and the total sum of Hammett σ values of the substituents is negative, and Ar ^2a is a benzene ring having a substituent, the substituent The sum of Hammett σ values of represents a positive one, and Z ⁻ represents a counter anion.
<8> The lithographic printing plate precursor as described in <7> above, wherein the iodonium salt represented by Formula 1a is an iodonium salt represented by Formula 2 below.

In the formula 2, R ¹ to R ⁶ each independently represent a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a halogen atom, a haloalkyl group, a cyano group, a nitro group, -OR ⁷ , -OCOR ⁷ , -OCONR ⁷ R ⁸ , -OSO ₂ R ⁷ , -OPO (OR ⁷ ) (OR ⁸ ), -OSi R ⁷ R ⁸ R ⁹ , -COR ⁷ , -COOR ⁷ , -CONR ⁷ R ⁸ , -NR ⁷ R ^{^{^{^{8, -NR 7 COR 8, -NR}}}} 7 COOR 8, -NR 7 CONR 8 R 9, -N (COR 7) (COR 8), - N + R 7 R 8 R 9 · Y -, -NR 7 SO ₂ R ⁸ , -SR ⁷ , -SOR ⁷ , -SO ₂ R ⁷ , -SO ₃ R ⁷ , -SO ₂ NR ⁷ R ⁸ , -PR ⁷ R ⁸ , -PO (OR ⁷ ) (OR ⁸ ), or represents -SiR ⁷ R ⁸ R ⁹ R ⁷ ~ ^{R 9} are each independently a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, or an alkynyl group, Z ^- and Y ^- is, each independently represents a counter ^{anion, R} 1 ~ All of R ³ will not be hydrogen atoms, and all of R ⁴ to R ⁶ will not be hydrogen atoms.
<9> The lithographic printing plate precursor as described in any one of <5> to <8> above, which further contains a borate compound as an electron donor polymerization initiator.
<10> The lithographic printing plate precursor as described in <9> above, wherein the borate compound is a tetraphenyl borate compound.
<11> The lithographic printing plate precursor as described in any one of <5> to <10> above, wherein the image recording layer further comprises an infrared absorber and a polymerizable compound.
<12> The lithographic printing plate precursor as described in any one of <5> to <11>, wherein the image recording layer contains a polymer particle.
<13> The lithographic printing plate precursor as described in any one of <1> to <4> above, wherein the image recording layer comprises an infrared absorber and hydrophobic thermoplastic polymer particles.
<14> The lithographic printing plate precursor as described in any one of <1> to <13> above, which is a lithographic printing plate precursor for on-press development.
<15> A step of imagewise exposing the lithographic printing plate precursor as described in any one of <1> to <14> above, and at least one of a printing ink and a fountain solution to obtain an unexposed portion of the image recording layer. A method of making a lithographic printing plate comprising the step of removing

According to an embodiment of the present disclosure, there is provided a lithographic printing plate precursor capable of suppressing the occurrence of a pot-like stain and having an excellent surface appearance, and a method of making a lithographic printing plate using the above lithographic printing plate precursor. can do.

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

(Lithographic printing plate precursor)
A lithographic printing plate precursor according to the present disclosure comprises an aluminum support and an image recording layer formed on the aluminum support, and a halide based on the total mass of all the layers formed on the aluminum support. The total content of ions is more than 0 ppm and not more than 1,000 ppm.
In addition, the lithographic printing plate precursor according to the present disclosure can be suitably used as a lithographic printing plate precursor for on-press development.

As a result of intensive investigations conducted by the present inventor, the adoption of the above-described configuration suppresses the occurrence of pot-like stains, and uses a lithographic printing plate precursor having an excellent surface appearance and the above-mentioned lithographic printing plate precursor. It has been found that a method of making a lithographic printing plate can be provided.
Although the detailed mechanism by which the said effect is acquired is unknown, it estimates as follows.
If the total content of halide ions based on the total mass of all layers formed on the aluminum support exceeds 1,000 ppm, corrosion of the aluminum support may occur. It is presumed that this is because a proton is generated by a local cell reaction or the like, and the proton and the halide ion are combined to generate a strong acid.
When the corrosion occurs in the non-image area of the lithographic printing plate precursor, the removal of the image recording layer by development may be insufficient in the corroded area. It is presumed that this is because a polymer is formed around the corroded portion. As a result, it is considered that a dot-like residual film is generated in the non-image area in the obtained lithographic printing plate.
In addition, when the total content of halide ions relative to the total mass of all layers formed on the aluminum support is 0 ppm, precipitates may be generated on the surface of the formed layer, It is thought that the surface condition of the surface of the deposited layer is deteriorated.
Therefore, as a result of intensive investigations by the present inventors, according to the lithographic printing plate precursor according to the present disclosure, generation of the above-mentioned defects is suppressed by the content of the halide ion being 1,000 ppm or less It became clear. It is presumed that this is because the occurrence of the corrosion is suppressed.
In addition, it has been revealed that when the content of the halide ion exceeds 0 ppm, it is possible to obtain a lithographic printing plate precursor having an excellent surface appearance. It is presumed that this is because the generation of the above-mentioned precipitates is suppressed by containing the halide ion.
Furthermore, when the content of the halide ion is 1,000 ppm or less, the number of printable lithographic printing plates (hereinafter, also referred to as "printing resistance") is likely to be improved. This is presumed to be due to an increase in the amount of radical production at the time of exposure since the consumption of the electron accepting polymerization initiator in the corroded portion is suppressed.
In addition, when the content of the halide ion is 1,000 ppm or less, the developability of the lithographic printing plate precursor is easily improved. This is considered to be because the lithographic printing plate precursor in the non-image area is easily removed by development because the polymerization in the corrosive area is suppressed.

<Content of halide ion>
The total content of halide ions relative to the total mass of all layers formed on the aluminum support in the lithographic printing plate precursor according to the present disclosure is more than 0 ppm and 1,000 ppm.
Examples of all layers formed on an aluminum support include layers such as an image recording layer, an undercoat layer and a protective layer, which will be described later.
The total content is preferably 500 ppm or less, more preferably 100 ppm or less, and still more preferably 10 ppm or less, from the viewpoint of suppressing the occurrence of pot-like dirt.
The total content of the halide ions is preferably 0.0005 ppm or more, and more preferably 0.005 ppm or more, from the viewpoint of improving the surface condition of the surface of the lithographic printing plate precursor.

The total content of the above halide ions is determined by extracting 100 cm ² of the lithographic printing plate precursor with 10 mL of pure water at 25 ° C., and quantifying with a Metrome 761 Compact IC. By the above extraction, halide ions contained in all layers on the aluminum support are extracted at one time. Thereafter, the total content is calculated from the sum of all the halide ions detected in the above determination.
Specifically, the extraction is performed by cutting the lithographic printing plate precursor to 10 cm × 10 cm and immersing it in 10 mL of pure water.

[Type of halide ion]
The planographic printing plate precursor according to the present disclosure has all the layers formed on the above-mentioned aluminum support from the viewpoint of suppressing the occurrence of a pot-like stain and improving the surface condition of the surface of the planographic printing plate precursor. Preferably, at least one selected from the group consisting of fluoride ion, chloride ion, bromide ion, and iodide ion as the above-mentioned halide ion is contained in any layer, and chloride ion and bromide ion are contained. It is more preferable to include at least one selected from the group consisting of

[Counter cation of halide ion]
The counter cation of the halide ion in the lithographic printing plate precursor according to the present disclosure may be an infrared absorber as long as the total content described above satisfies the above range, and an electron accepting polymerization initiator (for example, iodonium) It may be a cation etc.), may be a polymer component such as a binder polymer or particles, or may be other low molecular weight cation, and is not particularly limited.
That is, the halide ion contained in the lithographic printing plate precursor according to the present disclosure may be a halide ion derived from any component contained in the lithographic printing plate precursor.

Further, from the viewpoint of easy adjustment of the content of the halide ion, it is preferable that the counter cation of the halide ion is a quaternary ammonium cation.
The quaternary ammonium cation is not particularly limited, and examples thereof include tetraalkyl ammonium cation and the like. The carbon number of the alkyl group in the tetraalkylammonium cation is preferably independently 1 to 10, and more preferably 1 to 4.
That is, in the present disclosure, it is preferable that any layer formed on the aluminum support contains a halide of a quaternary ammonium cation.
Preferred examples of the halide of the quaternary ammonium cation include halides of tetraalkylammonium cation.
Preferred embodiments of the tetraalkylammonium cation are as described above, and the fluoride, chloride, bromide or iodide of the above tetraalkylammonium cation is preferable, and the chloride or bromide is more preferable.

<Method of adding halide ion>
The method of adding the halide ion to the lithographic printing plate precursor according to the present disclosure is not particularly limited, but the halide ion may be used as a component such as an infrared absorber, a binder polymer, or an electron accepting polymerization initiator contained in the image recording layer. The method of using the compound which generate | occur | produces, the method of adding a low molecular weight halide to an image recording layer, the method of using the compound which generate | occur | produces a halide ion in a protective layer or undercoat is mentioned.
In the present disclosure, as long as the total content of the halide ion falls within the above range, the halide ion may be added to any layer formed on the support in the lithographic printing plate by any of the above methods .
In addition, it is preferable to add a low molecular weight halide to any layer formed on an aluminum support from the viewpoint of easy addition because of high solubility in a solvent (and a coating solution), and a low molecular weight halide Is preferably added to the image recording layer.
The addition amount may be such that the total content of halide ions with respect to the total mass of all the layers formed on the aluminum support satisfies the above range.
The low molecular weight halide is not particularly limited, but the tetraalkyl ammonium cation and the halide ion as described above, such as tetraethyl ammonium bromide, tetrabutyl ammonium fluoride, tetrabutyl ammonium chloride, tetrabutyl ammonium bromide, tetrabutyl ammonium iodide, etc. And the like.

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

<Image recording layer>
The lithographic printing plate precursor according to the present disclosure has an image recording layer.
The image recording layer used in the present disclosure is preferably a negative image recording layer.
The image recording layer in the present disclosure is preferably any one of the following first aspect or second aspect from the viewpoint of printing durability and photosensitivity.
First embodiment: containing an electron accepting polymerization initiator.
Second embodiment: An infrared absorber and hydrophobic thermoplastic polymer particles are contained.
The image recording layer used in the present disclosure preferably further includes an infrared absorber and a polymerizable compound in the first embodiment from the viewpoint of press life and the like.
The image recording layer used in the present disclosure preferably further includes polymer particles in the first aspect from the viewpoint of printing durability and the like.
The image recording layer used in the present disclosure preferably further includes a borate compound as an electron donating polymerization initiator from the viewpoint of improving the printing durability and the visibility of the image portion of the plate.
From the viewpoint of printing durability, the image recording layer used in the present disclosure preferably further contains a binder polymer in the first aspect.
In addition, the image recording layer used in the present disclosure may contain hydrophobic thermoplastic polymer particles as the above-mentioned polymer particles in the above first aspect from the viewpoint of on-press developability.
The lithographic printing plate precursor according to the present disclosure is preferably removable from the unexposed area of the image recording layer by at least one of dampening water and printing ink, from the viewpoint of on-press developability.
The details of each component contained in the image recording layer will be described below.

[Electron-accepting type polymerization initiator]
The image recording layer used in the present disclosure preferably contains an electron accepting polymerization initiator, more preferably an electron accepting polymerization initiator and a polymerizable compound.
The electron accepting polymerization initiator is a compound that initiates and accelerates the polymerization of the polymerizable compound. As the electron accepting polymerization initiator, known thermal polymerization initiators, compounds having a small bond dissociation energy, photopolymerization initiators and the like can be used. Specifically, radical polymerization initiators described in paragraphs 0092 to 0106 of JP-A-2014-104631 can be used.

From the viewpoint of printing durability, preferred examples of the electron accepting polymerization initiator include onium salts. Among these, iodonium salt compounds and sulfonium salts are more preferable, and iodonium salts are more preferable.
In addition, as the iodonium salt, a compound represented by the following formula 1 is preferable from the viewpoint of printing durability.

In Formula 1, Ar ¹ and Ar ² are benzene rings which may have a substituent, and the substituents of two benzene rings are different from each other, and at least one of the substituents of the benzene ring is A structure in which the sum of Hammett σ values is negative, Z ⁻ represents a counter anion.

In Formula 1, the substituents of two benzene rings are different from each other not only when the substituents which the two benzene rings have differ, but one of the benzene rings has a substituent and the other benzene ring has a substituent. Also includes the case where it does not have a substituent.

The compound represented by the formula 1 is preferably a compound represented by the following formula 1a.

In Formula 1a, Ar ^1a is a benzene ring having a substituent, and the total sum of Hammett σ values of the substituents is negative, and Ar ^2a is a benzene ring having a substituent, the substituent The sum of Hammett σ values of represents a positive one, and Z ⁻ represents a counter anion.

Equation 1, in formulas 1a, Z ^- counter anion represented by the halide ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, carboxylate ion, or be a sulfonic acid ion preferably More preferably, they are tetrafluoroborate ion, hexafluorophosphate ion, or perfluoroalkyl sulfonate ion.

In the present disclosure, the Hammett σ value is the meta-substituent, para-substituent on acid dissociation equilibrium of benzoic acid in water at 25 ° C., as described in the reference document “Chemical Seminar 10 Hammett side—structure and reactivity”. It is a value indicating the influence of the group. If it is negative, it is electron donative, and if it is positive it is electron withdrawing. As for the ortho substituent, the value of the p-position substituent is substituted.
When calculating the sum of Hammett .sigma. Values, use .sigma.m values for substituents in the m-position to the C-I bond and .sigma.p values for substituents in the p-position.
As iodonium salts represented by the formula 1 or formula 1a, any iodonium salt is suitably used, as long as it is an iodonium salt in which these Hammett σ values are summed in each benzene ring and the sum of at least one is negative. be able to.
As for the iodonium salt represented by Formula 1 or Formula 1a, it is preferable that the sum total of the Hammett alpha value of the substituent of two benzene rings is 0 or less together.

As long as the iodonium salts used in the present disclosure have different substituents of two benzene rings in Formula 1 and the sum of Hammett σ values of at least one of the benzene rings is negative, any iodonium salt may be used. Although an iodonium salt can also be used, a compound represented by the following formula 2 is more preferable.
The compounds represented by Formula 2 are iodonium salts in which two benzene ring substituents are different from each other, and the sum of Hammett σ values of at least one benzene ring substituent is negative.

In the formula 2, R ¹ to R ⁶ each independently represent a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a halogen atom, a haloalkyl group, a cyano group, a nitro group, -OR ⁷ , -OCOR ⁷ , -OCONR ⁷ R ⁸ , -OSO ₂ R ⁷ , -OPO (OR ⁷ ) (OR ⁸ ), -OSi R ⁷ R ⁸ R ⁹ , -COR ⁷ , -COOR ⁷ , -CONR ⁷ R ⁸ , -NR ⁷ R ^{^{^{^{8, -NR 7 COR 8, -NR}}}} 7 COOR 8, -NR 7 CONR 8 R 9, -N (COR 7) (COR 8), - N + R 7 R 8 R 9 · Y -, -NR 7 SO ₂ R ⁸ , -SR ⁷ , -SOR ⁷ , -SO ₂ R ⁷ , -SO ₃ R ⁷ , -SO ₂ NR ⁷ R ⁸ , -PR ⁷ R ⁸ , -PO (OR ⁷ ) (OR ⁸ ), or represents -SiR ⁷ R ⁸ R ⁹ R ⁷ ~ ^{R 9} are each independently a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, or an alkynyl group, Z ^- and Y ^- is, each independently represents a counter ^{anion, R} 1 ~ All of R ³ will not be hydrogen atoms, and all of R ⁴ to R ⁶ will not be hydrogen atoms.

Among the above-mentioned substituents, examples of substituents when the Hammett α value is positive or negative are shown below.
σ m> 0: halogen atom, haloalkyl group, cyano group, nitro group, -OCOR ⁷ , -OSO ₂ R ⁷ , -COR ⁷ , -COOR ⁷ , -CONR ⁷ R ⁸ , -SO ₂ R ⁷
σ m <0: -NR ⁷ R ⁸ , alkyl group σ p> 0: halogen atom, haloalkyl group, cyano group, cyano group, nitro group, -OCOR ⁷ , -OSO ₂ R ⁷ , -COR ⁷ , -COOR ⁷ , -CONR ⁷ R ⁸ , -SO ₂ R ⁷
σp <0: -NR ⁷ R ⁸ , -OR ⁷ , alkyl group

Hereinafter, preferred examples of the electron accepting polymerization initiator used in the present disclosure will be listed, but the present disclosure is not limited thereto. In addition to the following compounds, the below-mentioned I-1 to I-6 used in the examples are also specific examples of preferable embodiments of the electron accepting polymerization initiator used in the present disclosure.
In the present disclosure, Me represents a methyl group, Et represents an ethyl group, and Bu represents a butyl group.

The content of the electron accepting polymerization initiator is preferably 0.1% by mass to 50% by mass, and more preferably 0.5% by mass to 30% by mass, with respect to the total mass of the image recording layer, and 0.8% by mass. % To 20% by weight is particularly preferred. Within the above range, better exposure sensitivity can be obtained, and the occurrence of pot-shaped stains can be more easily suppressed.

[Infrared absorber]
The image recording layer preferably contains an infrared absorber.
The infrared absorber has a function of converting the absorbed infrared light into heat and a function of being excited by the infrared light to perform electron transfer and / or energy transfer to the electron accepting polymerization initiator. The infrared absorber used in the present disclosure is preferably a dye having an absorption maximum at a wavelength of 750 nm to 1,400 nm.

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

Specific examples of the cyanine dye include compounds described in paragraphs 0017 to 0019 of JP-A 2001-133969, paragraphs 0016 to 0021 of JP-A 2002-023360, and paragraphs 0012 to 0037 of JP-A 2002-040638. Compounds described in JP-A-2002-278057, preferably compounds described in paragraphs 0034-0041 in JP-A-2008-195018, particularly preferably compounds described in JP-A-2007-90850. And compounds described in paragraphs 0105 to 0113 of JP-A-2012-206495.
Further, compounds described in paragraphs 0008 to 0009 of JP-A-5-5005 and paragraphs 0022 to 0025 of JP-A 2001-222101 can also be preferably used.
As the pigment, the compounds described in paragraphs 0072 to 0076 of JP-A-2008-195018 are preferable.

The infrared absorber may be used alone or in combination of two or more. Moreover, you may use together a pigment and dye as an infrared rays absorber.
The content of the infrared absorbing dye in the image recording layer is preferably 0.1% by mass to 10.0% by mass, and more preferably 0.5% by mass to 5.0% by mass with respect to the total mass of the image recording layer. preferable.

[Polymerizable compound]
The image recording layer used in the present disclosure preferably contains a polymerizable compound.
The polymerizable compound used in the image recording layer may be, for example, a radically polymerizable compound or a cationically polymerizable compound, but an addition polymerizable compound having at least one ethylenically unsaturated bond (hereinafter referred to as And an ethylenically unsaturated compound). As the ethylenically unsaturated compound, a compound having at least one terminal ethylenic unsaturated bond is preferable, and a compound having two or more terminal ethylenic unsaturated bonds is more preferable. The polymerizable compound can have a chemical form such as, for example, a monomer, a prepolymer, that is, a dimer, a trimer or an oligomer, or a mixture thereof.

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

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

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

Also, urethane acrylates described in JP-A-51-37193, JP-B-2-32293, JP-B 2-16765, JP-A 2003-344997, JP-A 2006-65210, JP-B-58-49860, JP-B-56-17654, JP-B-62-39417, JP-B-62-39418, JP-A-2000-250211, JP-A-2007-94138. Urethane Compounds Having a Water-Based Skeleton, U.S. Pat. Nos. 7,153,632, JP-A-8-505,958, JP-A-2007-293221, JP-A-2007-293223, and Urethane Compounds Having a Hydrophilic Group Is also suitable.

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

[Polymer particles]
The image recording layer preferably contains polymer particles.
The polymer particles may be selected from the group consisting of thermoplastic polymer particles, heat-reactive polymer particles, polymer particles having a polymerizable group, microcapsules containing a hydrophobic compound, and microgels (crosslinked polymer particles). preferable. Among them, polymer particles or microgels having a polymerizable group are preferable. In a particularly preferred embodiment, the polymer particles comprise at least one ethylenically unsaturated polymerizable group. The presence of such polymer particles has the effect of enhancing the printing durability of the exposed area and the on-press developability of the unexposed area.
The polymer particles are preferably thermoplastic polymer particles, and more preferably hydrophobic thermoplastic polymer particles.

As thermoplastic polymer particles, for example, Research Disclosure No. 1 of January 1992. The thermoplastic polymer particles described in 33303, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250, European Patent 931647, and the like are preferable.
Specific examples of the polymer constituting the thermoplastic polymer particles include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, and polyalkylene structure. Mention may be made of homopolymers or copolymers of monomers such as acrylates or methacrylates or mixtures thereof. Preferably, polystyrene, a copolymer containing styrene and acrylonitrile, or polymethyl methacrylate can be mentioned. The average particle size of the thermoplastic polymer particles is preferably 0.01 μm to 3.0 μm.

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

The thermally reactive group in the polymer particle having a thermally reactive group may be any functional group that carries out any reaction, as long as a chemical bond is formed, but is preferably a polymerizable group, for example, Ethylenically unsaturated group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group etc.) which performs radical polymerization reaction, cationically polymerizable group (for example, vinyl group, vinyloxy group, epoxy group, oxetanyl group etc.), addition reaction Group having an active hydrogen atom (eg, an amino group, a hydroxy group, a carboxy group, etc.) which is an active hydrogen atom which is a reaction partner thereof, a carboxy group which performs a condensation reaction, and Hydroxy group or amino group that is a reaction partner, acid anhydride that performs ring-opening addition reaction, and amino acid that is a reaction partner And a group or hydroxy group are preferably exemplified.

As the microcapsules, for example, as described in JP-A-2001-277740 and JP-A-2001-277742, at least a part of the components of the image recording layer is encapsulated in the microcapsule. The components of the image recording layer can also be contained outside the microcapsules. The image recording layer containing microcapsules is a preferred embodiment in which the hydrophobic component is encapsulated in the microcapsule and the hydrophilic component is contained outside the microcapsule.

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

Known methods can be applied to microencapsulate or microgelate the components of the image recording layer.

Further, as polymer particles, from the viewpoint of printing durability, stain resistance and storage stability, a polyvalent isocyanate compound which is an adduct of a polyhydric phenol compound having two or more hydroxy groups in the molecule and isophorone diisocyanate. And those obtained by the reaction of a compound having active hydrogen are preferable.
As said polyhydric phenol compound, the compound which has two or more benzene rings which have a phenolic hydroxyl group is preferable.
The compound having active hydrogen is preferably a polyol compound or a polyamine compound, more preferably a polyol compound, and still more preferably at least one compound selected from the group consisting of propylene glycol, glycerin and trimethylolpropane.
Examples of particles of resins obtained by the reaction of a polyhydric isocyanate compound which is an adduct of a polyhydric phenol compound having two or more hydroxy groups in a molecule and isophorone diisocyanate and a compound having an active hydrogen are disclosed in JP-A 2012 Preferred are polymer particles described in paragraphs 0032 to 0095 of JP-206495.

Furthermore, the polymer particle has a hydrophobic main chain from the viewpoint of printing durability and solvent resistance, and i) a constituent unit having a pendant cyano group directly bonded to the hydrophobic main chain, ii) It is preferable to include both of the constituent units having a pendant group containing a hydrophilic polyalkylene oxide segment.
An acrylic resin chain is preferably mentioned as the above-mentioned hydrophobic main chain.
Preferred examples of the pendant cyano group include — [CH ₂ CH (C≡N) —] or — [CH ₂ C (CH ₃ ) (C≡N) —].
Also, the constituent units having the pendant cyano group can be easily derived from an ethylenically unsaturated monomer such as acrylonitrile or methacrylonitrile, or a combination thereof.
Moreover, as an alkylene oxide in the said hydrophilic polyalkylene oxide segment, ethylene oxide or a propylene oxide is preferable and ethylene oxide is more preferable.
The repeating number of the alkylene oxide structure in the hydrophilic polyalkylene oxide segment is preferably 10 to 100, more preferably 25 to 75, and still more preferably 40 to 50.
Both a constituent unit having a hydrophobic main chain and i) having a pendant cyano group directly bonded to the hydrophobic main chain, and ii) a constituent unit having a pendant group including a hydrophilic polyalkylene oxide segment Preferred examples of the resin particles containing at least one of those described in JP-A-2008-503365, paragraphs 0039 to 0068.

The average particle diameter of the polymer particles is preferably 0.01 μm to 3.0 μm, more preferably 0.03 μm to 2.0 μm, and still more preferably 0.10 μm to 1.0 μm. Within this range, good resolution and stability over time can be obtained.
The average primary particle size of each particle in the present disclosure is measured by light scattering, or an electron micrograph of the particle is taken, and a total of 5,000 particle sizes of the particle are measured on the photograph, and an average is obtained. The value shall be calculated. For non-spherical particles, the particle size value of spherical particles having the same particle area as the particle area on the photograph is taken as the particle size.
Moreover, the average particle diameter in this indication shall be a volume average particle diameter unless there is particular notice.
The content of the polymer particles is preferably 5% by mass to 90% by mass with respect to the total mass of the image recording layer.

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

Among these electron donating polymerization initiators, the image recording layer preferably contains a borate compound. As the borate compound, a tetraaryl borate compound or a monoalkyl triaryl borate compound is preferable, from the viewpoint of the stability of the compound, a tetraaryl borate compound is more preferable, and a tetraphenyl borate compound is particularly preferable.
Moreover, as the borate compound, a tetraaryl borate compound having at least one electron withdrawing group is preferable, and a tetraphenyl borate compound having at least one electron withdrawing group is more preferable.
As the electron withdrawing group, a group having a positive Hammett's σ value is preferable, and a group having a Hammett's σ value of 0 to 1.2 is more preferable. For Hammett's σ values (σp and σm values), see Hansch, C., et al. Leo, A .; Taft, R .; W. Chem. Rev. 1991, 91, 165-195.
As an electron withdrawing group, a halogen atom, a trifluoromethyl group or a cyano group is preferable, and a fluorine atom, a chlorine atom, a trifluoromethyl group or a cyano group is more preferable.
As a counter cation which a borate compound has, an alkali metal ion or a tetraalkyl ammonium ion is preferable, and a sodium ion, a potassium ion, or a tetrabutyl ammonium ion is more preferable.

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

The electron donating polymerization initiator may be added alone or in combination of two or more.
The content of the electron donating polymerization initiator is preferably 0.01% by mass to 30% by mass, more preferably 0.05% by mass to 25% by mass, based on the total mass of the image recording layer, and 0.1% by mass It is more preferable that the content be up to 20% by mass.

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

Among them, as the binder polymer, known binder polymers used in the image recording layer of a lithographic printing plate precursor can be suitably used. As an example, a binder polymer (hereinafter, also referred to as a binder polymer for on-press development) used for an on-press development type lithographic printing plate precursor will be described in detail.
As a binder polymer for on-press development, a binder polymer having an alkylene oxide chain is preferable. The binder polymer having an alkylene oxide chain may have a poly (alkylene oxide) moiety in the main chain or in the side chain. Also, it may be a graft polymer having poly (alkylene oxide) in the side chain, or a block copolymer of a block composed of poly (alkylene oxide) -containing constitutional units and a block composed of poly (alkylene oxide) -free constitutional units. .
When it has a poly (alkylene oxide) site in the main chain, a polyurethane resin is preferred. The polymer of the main chain in the case of having a poly (alkylene oxide) moiety in the side chain includes (meth) acrylic resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, polyimide resin, polyamide resin, epoxy resin, polystyrene resin, novolac type Phenol resins, polyester resins, synthetic rubbers and natural rubbers may be mentioned, and (meth) acrylic resins are particularly preferred.

As the alkylene oxide, an alkylene oxide having 2 to 6 carbon atoms is preferable, and ethylene oxide or propylene oxide is particularly preferable.
The repeating number of the alkylene oxide in the poly (alkylene oxide) portion is preferably 2 to 120, more preferably 2 to 70, and still more preferably 2 to 50.
If the number of repetitions of the alkylene oxide is 120 or less, it is preferable because deterioration in both printing durability due to abrasion and printing durability due to ink receptivity is suppressed.

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

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

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

As an example of the residue having the ethylenically unsaturated bond (the above R),-(CH ₂ ) _n CR ^1A = CR ^{2 AR} 3 ^-A ,-(CH ₂ O) _n CH ₂ CR ^{1 A} = CR ² AR ^{3 A} ,- _{_{_{_{(CH 2 CH 2 O) n}}}} CH 2 CR 1A = CR 2A R 3A, - (CH 2) n NH-CO-O-CH 2 CR 1A = CR 2A R 3A, - (CH 2) n -O-CO -CR ^1A = CR ^2A R ^3A and-(CH ₂ CH ₂ O) ₂ -X (wherein, R ^1A to R ^3A are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group R ^1A and R ^2A or R ^3A may combine with each other to form a ring, n represents an integer of 1 to 10, and X represents a dicyclopentan. Represents a dienyl residue)) Rukoto can.

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

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

The content of the crosslinkable group in the binder polymer (content of the radically polymerizable unsaturated double bond by iodine titration) is preferably 0 per gram of the binder polymer from the viewpoint of good sensitivity and good storage stability. 1 mmol to 10.0 mmol, more preferably 1.0 mmol to 7.0 mmol, particularly preferably 2.0 mmol to 5.5 mmol.

Specific examples 1 to 11 of the binder polymer for on-press development are shown below, but the present disclosure is not limited thereto. In the following exemplified compounds, the numerical values (numerical values indicated simultaneously with the main chain constituent units) indicated in parallel with the constituent units represent the molar percentage of the above-mentioned constituent units. The numerical value added to the constituent unit of the side chain indicates the number of repetition of the above constituent unit. Also, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

In addition, as another preferable example of the binder polymer, a polymer chain having a sulphide bond with a nucleus via a core having a polyfunctional thiol having 6 to 10 functional groups as a nucleus, and the polymer chain having a polymerizable group is high Molecular compounds (hereinafter, also referred to as star polymer compounds) can be mentioned. As the star polymer compound, for example, compounds described in JP-A-2012-148555 can be preferably used.

The star polymer compound has a polymerizable group such as an ethylenically unsaturated bond for improving the film strength of the image area as described in JP-A-2008-195018, which is a main chain or a side chain, preferably a side. What has in the chain is mentioned. The polymerizable groups form crosslinks between polymer molecules to accelerate curing.
The polymerizable group is preferably an ethylenically unsaturated group such as (meth) acrylic group, vinyl group, allyl group or styryl group, an epoxy group or the like, and the (meth) acrylic group, vinyl group or styryl group is polymerizable. It is more preferable from the viewpoint, and (meth) acrylic group is particularly preferable. These groups can be introduced into the polymer by polymer reaction or copolymerization. For example, reaction of a polymer having a carboxy group in a side chain with glycidyl methacrylate, or reaction of a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid can be used. These groups may be used in combination.

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

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

The binder polymer may be present in the image recording layer as a polymer that functions as a binder for each component, or may be present in the form of particles. When present in the form of particles, the average primary particle size is preferably 10 nm to 1,000 nm, more preferably 20 nm to 300 nm, still more preferably 30 nm to 120 nm.
In addition, the compound applicable to the above-mentioned polymer particle shall not apply to a binder polymer.

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

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

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

The chain transfer agent may be used alone or in combination of two or more.
The content of the chain transfer agent is preferably 0.01% by mass to 50% by mass, more preferably 0.05% by mass to 40% by mass, and still more preferably 0.1% by mass to 30% by mass with respect to the total mass of the image recording layer. % Is more preferred.

[Low molecular weight hydrophilic compound]
The image recording layer may contain a low molecular weight hydrophilic compound in order to improve the on-press developability while suppressing the deterioration of the printing durability. The low molecular weight hydrophilic compound is preferably a compound having a molecular weight of less than 1,000, more preferably a compound having a molecular weight of less than 800, and still more preferably a compound having a molecular weight of less than 500.
Examples of low molecular weight hydrophilic compounds include water-soluble organic compounds. Examples of water-soluble organic compounds include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and their ether or ester derivatives, glycerin, pentaerythritol, tris (2-hydroxy) Ethyl) polyols such as isocyanurate, organic amines such as triethanolamine, diethanolamine, monoethanolamine and their salts, organic sulfonic acids such as alkylsulfonic acid, toluenesulfonic acid, benzenesulfonic acid and their salts, alkylsulfamic acid Organic sulfamic acids and their salts, organic sulfuric acids such as alkyl sulfuric acid and alkyl ether sulfuric acid and their salts, organic phosphonic acids such as phenyl phosphonic acid and the like , Tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids, betaines, and the like.

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

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

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

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

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

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

[Sepetic agent]
The image recording layer may contain a sensitizing agent such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer in order to improve the receptivity. In particular, when an inorganic stratiform compound is contained in the protective layer, these compounds function as a surface coating agent for the inorganic stratiform compound and can suppress the decrease in the receptivity during printing by the inorganic stratiform compound.
As a sensitizing agent, it is preferable to use a phosphonium compound, a nitrogen-containing low molecular weight compound, and an ammonium group-containing polymer in combination, and to use a phosphonium compound, a quaternary ammonium salt, and an ammonium group-containing polymer in combination. Is more preferred.

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

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

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

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

Below, the specific example of an ammonium group containing polymer is shown.
(1) 2- (trimethylammonio) ethyl methacrylate = p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90, Mw 45,000)
(2) 2- (trimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 60,000)
(3) 2- (ethyldimethylammonio) ethyl methacrylate = p-toluenesulfonate / hexyl methacrylate copolymer (molar ratio 30/70, Mw 45,000)
(4) 2- (trimethylammonio) ethyl methacrylate = hexafluorophosphate / 2-ethylhexyl methacrylate copolymer (molar ratio 20/80, Mw 60000)
(5) 2- (trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60, Mw 70000)
(6) 2- (Butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75, Mw 65,000)
(7) 2- (butyldimethylammonio) ethyl acrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80, Mw 65,000)
(8) 2- (butyldimethylammonio) ethyl methacrylate = 13-ethyl-5,8,11-trioxa-1-heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 , Mw 75,000)
(9) 2- (butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate / 2-hydroxy-3-methacryloyloxypropyl methacrylate copolymer (molar ratio 15/80/5, Mw 65,000)

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

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

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

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

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

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

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

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

3- (2-Methyl-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-n-propoxycarbonylamino-4-di-n -Propylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-methylamino-4-di-n-propylaminophenyl) -3- (1 -Ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-methyl-4-din-hexylaminophenyl) -3- (1-n-octyl-2-methylindole-3-) Yl) -4,7-diazaphthalide, 3,3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3,3-bis (1-n-octyl-2-methylindole 3-yl) -4-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- (2-ethoxy-) 4-diethylaminophenyl) -3- (1-octyl-2-methylindol-3-yl) -4 or 7-azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2) -Methylindol-3-yl) -4 or 7-azaphthalide, 3- (2-hexyloxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4 or 7- Azaphthalide, 3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-phenylindol-3-yl) -4 or 7-azaphthalide, -(2-butoxy-4-diethylaminophenyl) -3- (1-ethyl-2-phenylindol-3-yl) -4 or 7-azaphthalide 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3-phenylspirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho (3-methoxybenzo) spiropyran, 3-propylspirodibenzopyran-3,6-bis (dimethylamino) fluorene-9-spiro-3 Phthalides such as '-(6'-dimethylamino) phthalide, 3,6-bis (diethylamino) fluoren-9-spiro-3'-(6'-dimethylamino) phthalide,

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

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

It is also possible to use a commercially available product as an acid color developing agent, such as ETAC, RED 500, RED 520, CVL, S-205, BLACK 305, BLACK 400, BLACK 100, BLACK 500, H-7001, GREEN 300, NIRBLACK 78, BLUE 220, H. -3035, BLUE 203, ATP, H-1046, H-2114 (above, Fukui Yamada Chemical Industry Co., Ltd.), ORANGE-DCF, Vermilion-DCF, PINK-DCF, RED-DCF, BLMB, CVL, GREEN-DCF , TH-107 (manufactured by Hodogaya Chemical Co., Ltd.), ODB, ODB-2, ODB-4, ODB-250, ODB-Black XV, Blue-63, Blue-502, GN-169, GN-2, Gre n-118, Red-40, Red-8 (manufactured by Yamamoto Chemicals Co., Ltd.), crystal violet lactone (manufactured by Tokyo Kasei Kogyo Co., Ltd.), and the like. Among these commercially available products, ETAC, S-205, BLACK 305, BLACK 400, BLACK 100, BLACK 500, H-7001, GREEN 300, NIRBLACK 78, H-3035, ATP, H-1046, H-2114, GREEN-DCF, Blue-63. GN-169 and crystal violet lactone are preferable because the visible light absorptivity of the formed film is good.

These acid color formers may be used alone or in combination of two or more.

[Colorant]
The image recording layer of the lithographic printing plate precursor according to the present disclosure can contain a dye having large absorption in the visible light region as a colorant for an image. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (Oriental Chemical Industrial Co., Ltd.) Victoria Pure Blue, Crystal Violet (CI 42 555), Methyl Violet (CI 4 2535), Ethyl Violet, Ethyl Violet 6 HNAPS, Rhodamine B (CI 145 170 B), Malachite Green (CI 4 2000), Methylene Blue (CI 5 2015) Mention may be made of the dyes described in JP-A-62-293247. In addition, pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide can also be suitably used. It is preferable to contain a coloring agent, because the image area after image formation and the non-image area can be easily distinguished.
The addition amount of the colorant is preferably 0.005% by mass to 10% by mass with respect to the total mass of the image recording layer.

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

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

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

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

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

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

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

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

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

<Protective layer>
The lithographic printing plate precursor according to the present disclosure preferably has a protective layer (sometimes referred to as an overcoat layer) on the image recording layer. The protective layer has a function of preventing the generation of a scratch in the image recording layer and a function of preventing ablation during high-intensity laser exposure, in addition to the function of suppressing the image formation inhibition reaction by oxygen blocking.

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

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

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

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

As for the shape of the mica compound, from the viewpoint of diffusion control, the thinner the thickness, the better, and the flat size is better as long as it does not impair the smoothness of the coated surface and the transparency of the actinic light. Therefore, the aspect ratio is preferably 20 or more, more preferably 100 or more, and particularly preferably 200 or more. The aspect ratio is the ratio of the major axis to the thickness of the particle, and can be measured, for example, from a projection of the particle by a micrograph. The larger the aspect ratio, the greater the effect obtained. The upper limit value of the aspect ratio is not limited, and can be, for example, 1000 or less.

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

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

The protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving the coatability, and inorganic particles for controlling the slipperiness of the surface. Further, the oil-receptive agent described in the image recording layer may be contained in the protective layer.

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

(Method of preparing a lithographic printing plate)
A lithographic printing plate can be produced by imagewise exposing the lithographic printing plate precursor according to the present disclosure and performing development processing.
One embodiment of a method of preparing a lithographic printing plate according to the present disclosure comprises a step of imagewise exposing the lithographic printing plate precursor according to the present disclosure (hereinafter also referred to as “exposure step”), and printing ink and dampening water A step of removing the unexposed area of the image recording layer (hereinafter, also referred to as an "on-machine development step") is included in this order by at least one side.
Further, another embodiment of the method for producing a lithographic printing plate according to the present disclosure is an exposure step of imagewise exposing the lithographic printing plate precursor according to the present disclosure to form an exposed portion and an unexposed portion; A step (hereinafter, also referred to as a “developing step”) of removing the unexposed area by supplying a developer solution of 2 or more and 11 or less is included in this order.
Hereinafter, the preferable aspect of each process is demonstrated in order about the preparation methods of the lithographic printing plate concerning this indication, and the lithographic printing method concerning this indication. The lithographic printing plate precursor according to the present disclosure can also be developed by a developer.

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

<On-machine development process and development process>
The method of preparing a lithographic printing plate according to the present disclosure preferably includes an on-press development step of supplying at least one of printing ink and dampening water to remove the unexposed area.
In addition, the method of preparing a lithographic printing plate according to the present disclosure may be performed by a method of developing with a developer (developer processing method).
For example, the method of preparing a lithographic printing plate according to the present disclosure includes a developing step of supplying a developer having a pH of 2 or more and 11 or less to remove the unexposed area.
The on-press development method will be described below.

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

As a laser for imagewise exposing the lithographic printing plate precursor according to the present disclosure, the wavelength of the light source is preferably 300 nm to 450 nm or 750 nm to 1,400 nm. In the case of a light source of 300 nm to 450 nm, a lithographic printing plate precursor containing a sensitizing dye having an absorption maximum in this wavelength region in the image recording layer is preferably used, and the light source of 750 to 1,400 nm is preferably the one described above. Be A semiconductor laser is preferable as a light source of 300 nm to 450 nm.

[Developer processing method]
The lithographic printing plate precursor according to the present disclosure can also produce a lithographic printing plate by development processing using a developer by appropriately selecting a binder polymer and the like which are constituent components of the image recording layer. An embodiment using a developer having a pH of 2 to 11 which may contain at least one compound selected from the group consisting of a surfactant and a water-soluble polymer compound (also referred to as a simple development treatment) )including.

The development and the gum solution processing step can also be carried out simultaneously by a method of containing a water-soluble polymer compound, if necessary, in the developer.
Therefore, the post-water washing step is not particularly required, and the drying step can be carried out after development and gum solution treatment are carried out in one-component and one-step steps. Therefore, as a development process using a developing solution, a method of preparing a lithographic printing plate including a process of developing the planographic printing plate precursor after image exposure with a developing solution having a pH of 2 to 11 is preferable. It is preferable to dry after removing an excess developing solution using a squeeze roller after development processing.

That is, in the development step of the method for producing a lithographic printing plate according to the present disclosure, it is preferable to perform development processing and gum solution processing in one step for one solution.
In order to carry out development and gum solution treatment in one solution one step, not to carry out development treatment and gum solution treatment as separate steps, but to carry out development treatment and gum solution treatment in one step with one solution. Means

The development process can be suitably carried out by an automatic development processor equipped with a developer supply means and a rubbing member. Particularly preferred is an automatic development processor using a rotating brush roll as the rubbing member.
Two or more rotating brush rolls are preferable. Furthermore, it is preferable that the automatic development processor comprises means for removing excess developer such as a squeeze roller, and drying means such as a hot air device after the development processing means. In addition, the automatic development processor may be provided with preheating means for heat-processing the lithographic printing plate precursor after image exposure, prior to the development processing means.
The processing with such an automatic development processor corresponds to the development residue derived from the image recording layer (and the protective layer if the lithographic printing plate precursor has a protective layer) which occurs in the case of so-called on-press development processing. It has the advantage of being released from

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

It is preferable that an apparatus having a simplified structure and a simplified process be used for the development processing.
In alkali development, the protective layer is removed by a pre-water washing step, followed by development with a high pH alkaline developer, after which the alkali is removed in a post-water washing step, gum treatment is performed in the gumming step, and drying step To dry. In the simple development process, development and gumming can be performed simultaneously with one solution. Therefore, it is possible to omit the post-water washing step and the gum treatment step, and it is preferable to carry out the drying step as necessary after performing development and gumming (gum solution treatment) with one solution.
Furthermore, it is preferable to simultaneously perform removal of the protective layer, development and gumming in one solution without performing a pre-water washing step. Moreover, after developing and gumming, it is preferable to dry after removing an excess developing solution using a squeeze roller.

In the development step, the lithographic printing plate precursor may be immersed in the developing solution once, or may be immersed twice or more. Among them, a method of immersing the lithographic printing plate precursor in the developer solution once or twice is preferable.
In the immersion, the exposed lithographic printing plate precursor may be dipped in a developer tank containing the developer, or the developer may be sprayed from a spray or the like onto the plate surface of the exposed lithographic printing plate precursor.
Even in the case of immersing in the developer twice or more, the same developer, or a developer (fatigue solution) in which the components of the image recording layer are dissolved or dispersed by the developing process and the developer are used twice. In the case of the above immersion, it is referred to as development treatment with one solution (one solution treatment).

In the development processing, it is preferable to use a rubbing member, and it is preferable that a rubbing member such as a brush be installed in the developing bath for removing the non-image portion of the image recording layer.
In the development process, the exposed lithographic printing plate precursor is dipped in a developer and rubbed with a brush, for example, at a temperature of preferably 0 ° C. to 60 ° C., more preferably 15 ° C. to 40 ° C. The treatment liquid charged in the external tank can be pumped up, sprayed from a spray nozzle, and rubbed with a brush. These development processes can also be performed several times in succession. For example, after the developer charged in an external tank is pumped up and sprayed from a spray nozzle and rubbed with a brush, the developer can be sprayed again from a spray nozzle and rubbed with a brush. When development is carried out using an automatic developing machine, it is preferable to recover the processing ability using a replenisher or a fresh developer because the developer becomes fatigued due to the increase of the processing amount.

For the development processing, a gum coater and an automatic developing machine which are conventionally known for a PS plate (Presitized Plate) and a CTP (Computer to Plate) can also be used. In the case of using an automatic developing machine, for example, a method in which a developer charged in a developer tank or a developer charged in an external tank is pumped up and treated by spraying from a spray nozzle, or in a tank filled with developer. Either a method in which the printing plate is conveyed by immersion in a submerged guide roll or the like for processing can be applied, or a so-called disposable processing method in which a substantially unused developer can be supplied and processed only for each plate can be applied. . In either method, one having a rubbing mechanism by a brush, molton, etc. is more preferable. For example, commercially available automatic developing machines (for example, Clean Out Unit C85 / C125, Clean-Out Unit + C85 / 120, FCF 85 V, FCF 125 V, FCF News (manufactured by Glunz & Jensen), Azura CX85, Azura CX125, Azura CX150 AGFA GRAPHICS Co., Ltd.), or an apparatus in which a laser exposure unit and an automatic processor unit are integrated.

The details of the components and the like of the developer used in the developing step are described below.

-PH-
The pH of the developer is preferably 2 to 11, more preferably 5 to 9, and still more preferably 7 to 9. From the viewpoint of developability and dispersibility of the image recording layer, it is more advantageous to set the pH value higher, but it is more effective to set the pH value lower for printability, particularly for the suppression of stains. is there.
Here, pH is a value measured at 25 ° C. using a pH meter (model number: HM-31, manufactured by Toa DK K. K.).

-Surfactant-
The developer may contain a surfactant such as an anionic surfactant, a nonionic surfactant, a cationic surfactant, or an amphoteric surfactant.
The developer preferably contains at least one selected from the group consisting of anionic surfactants and amphoteric surfactants, from the viewpoint of blanching.
Further, the developer preferably contains a nonionic surfactant, and contains a nonionic surfactant and at least one selected from the group consisting of an anionic surfactant and an amphoteric surfactant. Is more preferred.

As an anionic surfactant, the compound represented by following formula (I) is mentioned preferably.
R ¹ -Y ¹ -X ¹ (I)
In formula (I), R ¹ represents an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group or an aryl group which may have a substituent.
As the alkyl group, for example, an alkyl group having 1 to 20 carbon atoms is preferable, and specifically, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, hexyl group, 2-ethylhexyl group, Preferred examples include octyl group, decyl group, dodecyl group, hexadecyl group and stearyl group.
The cycloalkyl group may be monocyclic or polycyclic. The monocyclic type is preferably a monocyclic cycloalkyl group having a carbon number of 3 to 8, and more preferably a cyclopropyl group, a cyclopentyl group, a cyclohexyl group or a cyclooctyl group. Preferred examples of the polycyclic group include an adamantyl group, a norbornyl group, an isoboronyl group, a camphanyl group, a dicyclopentyl group, an α-pinel group and a tricyclodecanyl group.
The alkenyl group is preferably, for example, an alkenyl group having a carbon number of 2 to 20, and specific examples thereof preferably include a vinyl group, an allyl group, a butenyl group and a cyclohexenyl group.
The aralkyl group is preferably, for example, an aralkyl group having a carbon number of 7 to 12, and specific examples thereof preferably include a benzyl group, a phenethyl group and a naphthylmethyl group.
The aryl group is preferably, for example, an aryl group having a carbon number of 6 to 15, and specific examples thereof include a phenyl group, a tolyl group, a dimethylphenyl group, a 2,4,6-trimethylphenyl group, a naphthyl group and an anthryl group. Groups and 9,10-dimethoxyanthryl group etc. can be preferably mentioned.

As a substituent, a monovalent nonmetal atomic group other than a hydrogen atom is used, and preferred examples include a halogen atom (F, Cl, Br or I), a hydroxy group, an alkoxy group, an aryloxy group, an acyl group, Amide groups, ester groups, acyloxy groups, carboxy groups, carboxylic acid anion groups, sulfonic acid anion groups and the like can be mentioned.

Specific examples of the alkoxy group in the substituent include methoxy group, ethoxy group, propyloxy group, isopropyloxy group, butyloxy group, pentyloxy group, hexyloxy group, dodecyloxy group, stearyloxy group, methoxyethoxy group, poly ( Those having preferably 1 to 40 carbon atoms, more preferably 1 to 20 carbon atoms, such as ethyleneoxy) group, poly (propyleneoxy) group and the like can be mentioned. The aryloxy group has 6 to 18 carbon atoms, such as phenoxy, tolyloxy, xylyloxy, mesityloxy, cumenyloxy, methoxyphenyloxy, ethoxyphenyloxy, chlorophenyloxy, bromophenyloxy, naphthyloxy and the like The ones of Examples of the acyl group include those having 2 to 24 carbon atoms such as acetyl group, propanoyl group, butanoyl group, benzoyl group and naphthoyl group. Examples of the amide group include those having 2 to 24 carbon atoms such as an acetamide group, a propionic acid 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. As the acyloxy group, those having 2 to 20 carbon atoms such as acetoxy group, propanoyloxy group, benzoyloxy group, naphthoyloxy group and the like can be mentioned. Examples of the ester group include those having 1 to 24 carbon atoms such as methyl ester group, ethyl ester group, propyl ester group, hexyl ester group, octyl ester group, dodecyl ester group and stearyl ester group. The substituent may consist of a combination of two or more of the above substituents.

X ¹ represents a sulfonate group, a sulfate monoester base, a carboxylate group or a phosphate group.
Y ¹ is a single bond, -C _n H _2n- , -C _n _-m H _{2 (n-m)} OC _m H _2m- , -O- (CH ₂ CH ₂ O) _n- , -O- (CH ₂ CH ₂ CH ₂ O) _n- , -CO-NH-, or a divalent linking group consisting of a combination of two or more of these, and n 1 1 and n m m 0 0 are satisfied.

Among the compounds represented by the formula (I), a compound represented by the following formula (IA) or the formula (IB) is preferable from the viewpoint of scratch resistance.

In formulas (IA) and (IB), each of R ^A1 to R ^A10 independently represents a hydrogen atom or an alkyl group, nA represents an integer of 1 to 3, and X ^A1 and X ^A2 each represent Independently, it represents a sulfonate group, a sulfate monoester base, a carboxylate group or a phosphate group, and Y ^A1 and Y ^A2 each independently represent a single bond, —C _n H _{2 n} —, —C _n _-m H _{2 (n _{_{_{-m) OC m H 2m -,}}}} - O- (CH 2 CH 2 O) n -, - O- (CH 2 CH 2 CH 2 O) n -, - CO-NH-, or combining two or more And n ≧ 1 and n ≧ m ≧ 0, and the total number of carbons in R ^A1 to R ^A5 or R ^A6 to R ^A10 and in Y ^A1 or Y ^A2 is 3 or more. It is.

The total carbon number of R ^A1 to R ^A5 and Y ^1A , or R ^A6 to R ^A10 and Y ^{A2 in} the compound represented by the above formula (I-A) or formula (I-B) is 25 or less Is preferable, and 4 to 20 is more preferable. The structure of the alkyl group described above may be linear or branched.
X ^A1 and X ^A2 in the compound represented by the formula (IA) or the formula (IB) are preferably a sulfonate group or a carboxylate group. Further, the salt structure of X ^A1 and X ^A2 is preferably an alkali metal salt, because the solubility in an aqueous solvent is particularly good. Among them, sodium salts or potassium salts are particularly preferred.
As the compound represented by the above formula (IA) or formula (IB), the description in paragraphs [0019] to [0037] of JP-A-2007-206348 can be referred to.
As the anionic surfactant, compounds described in paragraphs 0023 to 0028 of JP-A-2006-65321 can also be suitably used.

The amphoteric surfactant to be used in the developer is not particularly limited, and amine oxides such as alkyldimethylamine oxide, alkylbetaines, fatty acid amidopropyl betaines, betaines such as alkylimidazole, amino acids such as sodium alkylamino fatty acid It can be mentioned.

In particular, alkyldimethylamine oxide which may have a substituent, alkyl carboxy betaine which may have a substituent, and alkyl sulfo betaine which may have a substituent are preferably used. Specific examples thereof include a compound represented by the formula (2) in paragraph 0256 of JP-A-2008-203359, a formula (I), a formula (II) and a formula (II) in paragraph 0028 of JP-A-2008-276166. Examples thereof include compounds represented by VI) and compounds described in paragraphs 0022 to 0029 of JP-A-2009-47927.

As the amphoteric surfactant used in the developer, a compound represented by the following formula (1) or a compound represented by the formula (2) is preferable.

In formulas (1) and (2), R ¹ and R ¹¹ each independently represent an alkyl group having 8 to 20 carbon atoms or a linking group having 8 to 20 carbon atoms in total.
R ² , R ³ , R ¹² and R ¹³ each independently represent a hydrogen atom, an alkyl group or a group containing an ethylene oxide structure.
R ⁴ and R ¹⁴ each independently represent a single bond or an alkylene group.
Moreover, two groups among R ¹ , R ² , R ³ and R ⁴ may be bonded to each other to form a ring structure, and two groups among R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may be each other It may combine to form a ring structure.

In the compound represented by the formula (1) or the compound represented by the formula (2), when the total carbon value becomes large, the hydrophobic portion becomes large, and the solubility in an aqueous developer decreases. In this case, the solubility is improved by mixing an organic solvent such as alcohol which helps dissolution with water as a solubilizing agent, but if the total carbon value becomes too large, a surfactant can be used within the proper mixing range. Can not be dissolved. Therefore, the total carbon number of R ¹ to R ⁴ or R ¹¹ to R ¹⁴ is preferably 10 to 40, more preferably 12 to 30.

The alkyl group having a linking group represented by R ¹ or R ¹¹ represents a structure having a linking group between the alkyl groups. That is, when there is one linking group, it can be represented by "-alkylene group-linking group-alkyl group". The linking group includes, for example, an ester bond, a carbonyl bond, and an amide bond. Although two or more linking groups may be present, one linking group is preferred, and an amide bond is particularly preferred. The total carbon number of the alkylene group to be bonded to the linking group is preferably 1 to 5. The alkylene group may be linear or branched, but a linear alkylene group is preferred. The alkyl group bonded to the linking group preferably has 3 to 19 carbon atoms, and may be linear or branched, but is preferably linear alkyl.

When R ² or R ¹² is an alkyl group, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. It may be either linear or branched, but is preferably a linear alkyl group.

When R ³ or R ¹³ is an alkyl group, the number of carbon atoms is preferably 1 to 5, particularly preferably 1 to 3. It may be either linear or branched, but is preferably a linear alkyl group.
As a group containing an ethylene oxide structure represented by R ³ or R ¹³ , a group represented by —R ^a (CH ₂ CH ₂ O) _n R ^b can be mentioned. Here, R ^a represents a single bond, an oxygen atom or a divalent organic group (preferably having a carbon number of 10 or less), R ^b represents a hydrogen atom or an organic group (preferably having a carbon number of 10 or less), and n is 1 Represents an integer of ~ 10.

When R ⁴ and R ¹⁴ are an alkylene group, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. It may be either linear or branched, but is preferably a linear alkylene group.
Or a compound represented by the formula (2) represented by the formula (1) preferably has an amide bond, and more preferably has an amide bond as the linking group R ¹ or R ^11.
Representative examples of the compound represented by the formula (1) or the compound represented by the formula (2) are shown below, but the present disclosure is not limited thereto.

The compounds represented by the formula (1) or (2) can be synthesized according to known methods. Moreover, it is also possible to use what is marketed. As commercially available products, examples of the compound represented by the formula (1) include Softazoline LPB manufactured by Kawaken Fine Chemicals Co., Ltd., Softazoline LPB-R, Vista MAP, Takesurf C-157L manufactured by Takemoto Yushi Co., Ltd., and the like. Examples of the compound represented by the formula (2) include softazoline LAO manufactured by Kawaken Fine Chemicals Co., Ltd., and Amogen AOL manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
The amphoteric surfactant may be used alone in the developer or may be used in combination of two or more.

Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ether, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, Propylene glycol mono fatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial ester, polyethylene glycol fatty acid ester, polyglycerin fatty acid partial ester, polyoxyethylene glycerin fatty acid partial ester , Polyoxyethylene diglycerins, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamine , Polyoxyethylene alkylamine, triethanolamine fatty acid esters, trialkylamine oxides, polyoxyethylene alkyl phenyl ethers, polyoxyethylene - polyoxypropylene block copolymers, and the like.
Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based surfactants and the like can also be used in the same manner. These surfactants can be used in combination of two or more.

The nonionic aromatic ether surfactant represented by the following formula (N1) is particularly preferable as the nonionic surfactant.
X ^N- Y ^N- O-(A ¹ ) ⁿ _B- (A ² ) _{m B-} H (N 1)
In the formula, X ^N represents an aromatic group which may have a substituent, Y ^N represents a single bond or an alkylene group having 1 to 10 carbon atoms, and A ¹ and A ² are groups different from each other And nB and mB each independently represent an integer of 0 to 100, provided that nB and mB simultaneously represent one of -CH ₂ CH ₂ O- or -CH ₂ CH (CH ₃ ) O- If non-zero and either nB or mB is zero, then nB and mB are not one.
In the formula, examples of the aromatic group of X ^N include a phenyl group, a naphthyl group and an anthranyl group. These aromatic groups may have a substituent. The substituent includes an organic group having 1 to 100 carbon atoms. In the formula, when both A and B are present, it may be a random or block copolymer.

Specific examples of the organic group having 1 to 100 carbon atoms include an aliphatic hydrocarbon group which may be saturated or unsaturated and may be linear or branched, an aromatic hydrocarbon group such as an alkyl group, an alkenyl group or an alkynyl group. , Aryl groups, aralkyl groups, etc. In addition, alkoxy group, aryloxy group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N -Arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N- Arylcarbamoyloxy group, acylamino group, N-alkylacylamino group, N-ary Acylamino group, acyl group, alkoxycarbonylamino group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group And N-alkyl-N-arylcarbamoyl groups, polyoxyalkylene chains, the above-mentioned organic groups to which a polyoxyalkylene chain is bonded, and the like. The alkyl group may be linear or branched.
In addition, as the nonionic surfactant, compounds described in paragraphs 0030 to 0040 of JP-A-2006-65321 can also be suitably used.

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

The surfactant may be used alone or in combination of two or more.
The content of the surfactant is preferably 1% by mass to 25% by mass, more preferably 2% by mass to 20% by mass, still more preferably 3% by mass to 15% by mass, with respect to the total mass of the developer. % To 10% by weight is particularly preferred. Within the above range, the scratch resistance is excellent, the dispersibility of development residue is excellent, and the ink receptivity of the obtained lithographic printing plate is excellent.

-Water soluble polymer compound-
The developer can contain a water-soluble polymer compound from the viewpoint of adjusting the viscosity of the developer and protecting the plate surface of the resulting lithographic printing plate.
Examples of water-soluble polymer compounds include soybean polysaccharides, modified starches, gum arabic, dextrin, fibrin derivatives (eg, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose etc.) and modified products thereof, pullulan, polyvinyl alcohol and derivatives thereof, polyvinyl pyrrolidone And water-soluble polymer compounds such as polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, etc. it can.

As the above-mentioned soybean polysaccharide, conventionally known ones can be used. For example, as a commercial product, there is trade name Soya Five (manufactured by Fuji Oil Co., Ltd.), and various grades can be used. Those which can be preferably used are those in which the viscosity of the 10% by mass aqueous solution is in the range of 10 mPa · s to 100 mPa · s.

As said modified starch, the starch represented by following formula (III) is preferable. As the starch represented by the formula (III), any starch such as corn, potato, tapioca, rice, wheat and the like can be used. The modification of these starches can be performed by a method of decomposing in the range of 5 to 30 glucose residues per molecule with an acid or enzyme or the like and further adding oxypropylene in an alkali.

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

Among the water-soluble polymer compounds, particularly preferred are soybean polysaccharides, modified starches, gum arabic, dextrin, carboxymethylcellulose, polyvinyl alcohol and the like.

The water-soluble polymer compound can be used in combination of two 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. . The viscosity of a developing solution is moderate as it is the said aspect, and it can suppress that development debris etc. accumulate on the roller member of an automatic developing machine.

-Other additives-
The developer used in the present disclosure may contain, in addition to the above, a wetting agent, a preservative, a chelating compound, an antifoaming agent, an organic acid, an organic solvent, an inorganic acid, an inorganic salt and the like.

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

As preservatives, phenol or derivatives thereof, formalin, imidazole derivative, sodium dehydroacetate, 4-isothiazolin-3-one derivative, benzisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, benztriazole derivative Amidine guanidine derivatives, quaternary ammonium salts, derivatives such as pyridine, quinoline, guanidine, etc., diazines, triazole derivatives, oxazoles, oxazine derivatives, 2-bromo-2-nitropropane-1,3-diol based on nitrobromo alcohol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.
The amount of the preservative to be added is an amount that exerts a stable effect on bacteria, mold, yeast and the like, and varies depending on the type of bacteria, mold and yeast, but is 0. 0 to the total mass of the developer. The range of 01% by mass to 4% by mass is preferable. In addition, it is preferable to use two or more preservatives in combination so as to be effective against various molds and sterilization.

As a chelate compound, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, hydroxyethylethylenediaminetriacetic acid , Its potassium salt, its sodium salt; nitrilotriacetic acid, its sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt, its sodium salt; aminotri (methylenephosphonic acid), its potassium salt, its sodium salt And organic phosphonic acids. Instead of sodium and potassium salts of chelating agents, salts of organic amines are also effective.
The chelating agent is preferably one that is stably present in the treatment liquid composition and does not inhibit printability. The content of the chelating agent is preferably 0.001% by mass to 1.0% by mass with respect to the total mass of the developer.

As the antifoaming agent, a general silicone-based self-emulsification type, an emulsification type, or a compound having a nonionic HLB (Hydrophilic-Lipophilic Balance) of 5 or less can be used. Silicone antifoams are preferred.
In addition, silicone type surfactant shall be regarded as an antifoamer.
The content of the antifoaming agent is preferably in the range of 0.001% by mass to 1.0% by 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, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, organic phosphonic acid and the like . The organic acids can also be used in the form of their alkali metal salts or ammonium salts. The content of the organic acid is preferably 0.01% by mass to 0.5% by mass with respect to the total mass of the developer.

As the organic solvent, for example, aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.), etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated Hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.), polar solvents and the like can be mentioned.

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

When the above organic solvent is insoluble in water, it can be used by solubilizing it in water using a surfactant etc. When the developer contains an organic solvent, it is safe and flammable From the viewpoint, the concentration of the solvent in the developer is preferably less than 40% by mass.

As the inorganic acid and inorganic salt, phosphoric acid, metaphosphoric acid, ammonium monophosphate, ammonium diphosphate, sodium monophosphate, sodium diphosphate, potassium monophosphate, potassium diphosphate, Sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogensulfate, nickel sulfate and the like can be mentioned. The content of the inorganic salt is preferably 0.01% by mass to 0.5% by mass with respect to the total mass of the developer.

The developer is prepared, as required, by dissolving or dispersing the above-mentioned components in water. The solid content concentration of the developer is preferably 2% by mass to 25% by mass. As a developing solution, it is possible to prepare a concentrated solution and dilute it with water before use.
The developer is preferably an aqueous developer.

The developer preferably contains an alcohol compound from the viewpoint of the dispersibility of the development residue.
As the alcohol compound, methanol, ethanol, propanol, isopropanol, benzyl alcohol and the like can be mentioned. Among them, benzyl alcohol is preferred.
The content of the alcohol compound is preferably 0.01% by mass to 5% by mass, and more preferably 0.1% by mass to 2% by mass, with respect to the total mass of the developer, from the viewpoint of the dispersibility of the development residue. .2% by weight to 1% by weight is particularly preferred.

<Printing process>
The lithographic printing method according to the present disclosure includes a printing step of supplying a printing ink to the planographic 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 desired. Moreover, as a printing ink, oil-based ink or an ultraviolet curing ink (UV ink) is mentioned preferably, UV ink is mentioned more preferably.
In the printing step, dampening water may be supplied as necessary.
The printing process may be performed continuously to the on-press development process without stopping the printing machine.
There is no restriction | limiting in particular as a recording medium, If desired, a well-known recording medium can be used.

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

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

<Preparation of Support 1>
In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) with a thickness of 0.3 mm, a degreasing treatment is carried out at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution. The surface of the aluminum plate was grained using ^three 3 mm bundle planting nylon brushes and a pumice-water suspension (specific gravity: 1.1 g / cm ³ ) having a median diameter of 25 μm, and thoroughly washed with water. The aluminum plate was etched by immersing it in a 25% by mass aqueous solution of sodium hydroxide at 45 ° C. for 9 seconds, washed with water, and further immersed in a 20% by mass aqueous solution of nitric acid at 60 ° C. for 20 seconds and washed with water. The etching amount of the grained surface was about 3 g / m ² .

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

Subsequently, nitric acid electrolysis is carried out using a 0.5 mass% aqueous solution of hydrochloric acid (containing 0.5 mass% of aluminum ion) and an electrolytic solution with a liquid temperature of 50 ° C. under the condition that the aluminum plate has an electric quantity of 50 C / dm ² at the anode. Electrochemical roughening treatment was carried out in the same manner as in the above, followed by washing with spray.
Next, using a 15% by weight aqueous sulfuric acid solution (containing 0.5% by weight of aluminum ion) at a liquid temperature of 54 ° C. as an electrolyte on an aluminum plate, a direct current anodic oxide film of 2.5 g / m ^{2 at} a current density of 15 A / dm ² After formation, it was washed with water and dried. The average pore diameter (surface average pore diameter) in the surface layer of the anodized film was 10 nm.
The measurement of the pore diameter in the surface layer of the anodized film uses an ultra-high resolution SEM (S-900 manufactured by Hitachi, Ltd.), and uses a deposition process or the like to impart conductivity at a relatively low acceleration voltage of 12 V. The surface was observed at a magnification of 150,000 times without application, and 50 pores were randomly extracted to obtain an average value. The standard error was less than ± 10%.

After that, in order to ensure the hydrophilicity of the non-image area, it is subjected to a silicate treatment by dipping for 7 seconds at 50 ° C. using a 2.5 mass% aqueous solution of sodium silicate No. 3 and then washing with water by spraying. Support 1 was produced. The adhesion amount of Si was 11 mg / m ² .

<Preparation of Support 2>
The aluminum alloy 1 having the composition described in the following Table 1 was melted and cast, and both surfaces of the obtained ingot were chamfered to form a thickness of 500 mm, a width of 1000 mm, and a length of 3500 mm. The obtained compact is homogenized at a temperature of 550 ° C., heated to a temperature of 400 ° C. to start hot rolling, hot rolled after cold rolling, and then continuous In the annealing furnace, an intermediate annealing (without holding at 500 ° C.) was performed to heat to a temperature of 500 ° C. Thereafter, finish cold rolling with a reduction in thickness of 80% was performed to obtain a plate having a thickness of 0.30 mm.

The obtained plate material (aluminum alloy plate) is degreased, neutralized and washed under the treatment conditions shown in Table 2, then subjected to alternating current electrolytic surface roughening treatment, and further to remove oxides formed by electrolysis The resultant was desmutted, washed with water, dried and cut into a predetermined size to obtain a support 2.

<Preparation of Support 3>
A support was produced as a support 3 in the same manner as the support 2 except that the aluminum alloy 2 having the composition shown in Table 3 below was used instead of the aluminum alloy 1.

<Preparation of undercoat layer coating solution>
Polymer (UC-1) [the following structure]: 0.18 parts Hydroxyethyliminodiacetic acid: 0.10 parts Water: 61.4 parts

Preparation of Coating Solution for Protective Layer
· Inorganic layered compound dispersion liquid (1) [below]: 1.5 parts Polyvinyl alcohol (CKS 50, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., sulfonic acid modified, saponification degree 99 mol% or more, polymerization degree 300) 6 mass% Aqueous solution: 0.55 parts · Polyvinyl alcohol (PVA-405, manufactured by Kuraray Co., Ltd., saponification degree 81.5 mol%, polymerization degree 500) 6 mass% aqueous solution: 0.03 parts · Surfactant (polyoxyethylene lauryl Ether, Emarex (registered trademark) 710, manufactured by Nippon Emulsion Co., Ltd., 1% by mass aqueous solution: 0.86 parts, ion exchanged water: 6.0 parts

The preparation method of the inorganic stratiform compound dispersion liquid (1) used for the said protective layer coating liquid is shown below.

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

Preparation of coating solution for image recording layer
Each component was added according to the usage described in Table 4 or Table 5, and the solvent was added and mixed so that the solid content concentration is 7.0% by mass. The addition amount (mass part) of each raw material of Table 4 or Table 5 is a solid content amount.
In Table 4 or Table 5, the description of “G-1 468” or the like means that the compound G-1 is contained in 468 parts by mass. In the solvent column, for example, “S-1 / S-2 / S-3 60/30/10”, 60% by mass of S-1, 30% by mass of S-2, and S-3 as a solvent. It shows that the mixed solvent which mixed the ratio of 10 mass% was used. Furthermore, the description of "-" indicates that the corresponding component is not contained.

(Examples 1 to 34 and Comparative Examples 1 to 2)
<Preparation of a lithographic printing plate precursor>
The lithographic printing plate precursors of Examples 1 to 34 and Comparative Examples 1 to 2 were produced by the following method.
The undercoat layer coating solution of the above composition was applied onto the support so that the dry coating amount would be 20 mg / m ² to form an undercoat layer.
In Example 29, tetraethylammonium bromide was added to the undercoat layer coating solution to obtain the halide ion amounts (ppm) described in Table 5.
Each image recording layer coating liquid described in Table 4 or Table 5 was bar-coated on the undercoat layer, and oven-dried at 120 ° C. for 40 seconds to form an image recording layer having a dry coating amount of 1.0 g / m ² . .
In Examples 1 to 7 and Comparative Examples 1 to 2, tetraethylammonium bromide was added to the image recording layer coating solution so that the halide ion amount (ppm) described in Table 4 or Table 5 was obtained.
In Example 9, tetrabutylammonium fluoride was added to the image recording layer coating solution so that the amount of halide ion (ppm) described in Table 4 would be obtained.
In Example 10, tetrabutyl ammonium chloride was added to the image recording layer coating solution so that the amount of halide ion (ppm) described in Table 4 would be obtained.
In Example 11, tetrabutylammonium bromide was added to the image recording layer coating solution so that the amount of halide ion (ppm) described in Table 4 was obtained.
In Example 12, tetrabutylammonium iodide was added to the image recording layer coating solution so that the amount of halide ion (ppm) described in Table 4 was obtained.
In Examples 13 to 15, tetraethylammonium bromide was added to the image recording layer coating solution such that the amount of halide ion (ppm) described in Table 4 was obtained.
In Examples 16 to 19, the infrared ray absorber (K-4) used contained a halide ion, and no additional halide ion was added.
In Examples 20 to 23, the electron-accepting polymerization initiator (I-4) used contained a halide ion, and the halide ion was not further added.
In Examples 24 to 27, the used binder polymer (B-1b) contained a halide ion, and the halide ion was not further added.
In Example 28 or 31 to 34, tetraethylammonium bromide was added to the image recording layer coating solution so that the amount of halide ion (ppm) described in Table 5 was obtained.
The types of supports used (support 1 to support 3) are described in Table 4 or Table 5.
If necessary, a protective layer coating solution of the above composition was bar-coated on the image recording layer, and oven-dried at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.15 g / m ² .
In Example 30, tetraethylammonium bromide was added to the protective layer coating solution so that the halide ion amounts (ppm) described in Table 5 were obtained.
An example in which the protective layer was formed was described as “present” in the column of the protective layer in Table 4 or Table 5.
In addition, the descriptions in the column of “Halogen ion amount (ppm)” in Table 4 or Table 5 are the values of all layers formed on the aluminum support in the lithographic printing plate precursor measured by the method described above. The total content of halide ions relative to the total mass is shown. The description of "0" in the column of "Halogenide ion amount (ppm)" means that the halide ion was not detected (less than the detection limit) by the above method.

Specifically, the above “halide ion amount (ppm)” in Table 4 or Table 5 is obtained by extracting 100 cm ² of the lithographic printing plate precursor with 10 mL of pure water at 25 ° C., Metrome 761 Compact IC It quantified by. By the above extraction, the halide ions contained in all the layers on the aluminum support were extracted at one time. Thereafter, the total content was calculated from the sum of all the halide ions detected in the above determination.
Specifically, the extraction was performed by cutting the lithographic printing plate precursor to 10 cm × 10 cm and immersing it in 10 mL of pure water.

<Evaluation of lithographic printing plate precursor>
The lithographic printing plate precursor prepared as described above was subjected to an output of 27 W, an outer drum rotational speed of 450 rpm, and a resolution of 2,400 dpi (dot per inch, 1 inch is 2.54 cm) at a Magnus 800 Quantum manufactured by Kodak equipped with an infrared semiconductor laser. It exposed (The irradiation energy 110 mJ / cm < ² > equivalent) on condition of. The exposed image included a solid image and an AM screen (Amplitude Modulation Screen) chart of 3% halftone dots.

(1) On-press developability The obtained exposed original plate was mounted on a cylinder of a Kiku-size (636 mm × 939 mm) Heidelberg printing machine SX-74 without development processing. A dampening water circulation tank with a capacity of 100 L containing a non-woven fabric filter and a temperature control device was connected to this printing press. Dampening water S-Z1 (Fuji Film Co., Ltd. product) 80L of dampening water of 2.0% is charged into a circulation device, and T & K UV OFS K-HS black ink GE-M (trade Co., Ltd. made by T & K TOKA) as a printing ink The dampening water and the ink were supplied by a standard automatic printing start method, and 500 sheets were printed on Tokiwa Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
In the above on-press development, the number of printing sheets required until the ink was not transferred to the non-image area was measured as on-press developability. The measurement results are shown in Table 4 or Table 5.

(2) Printing durability After evaluating the on-press developability described above, printing was continued. As the number of printed sheets increased, the image area was gradually worn away, and the ink density on the printed matter decreased. The number of printed copies when the value obtained by measuring the halftone dot area rate of 3% halftone screen of AM screen with a Gretag densitometer (manufactured by GretagMacbeth) is 1% lower than the measured value of the 500th printed sheet The printing durability was evaluated. It evaluated by relative printing resistance which makes 100 the case where the number of printed sheets is 50,000 sheets. As the numerical value is larger, the printing durability is better. The evaluation results are shown in Table 4 or Table 5.
Relative printing durability = (number of copies of target lithographic printing plate precursor) / 50,000 × 100

(3) Pot-like stain After the lithographic printing plate precursor obtained in each Example or Comparative Example was conditioned with a paper sheet for 1 hour in an environment of 25 ° C. and 70% RH and packaged in aluminum kraft paper, Heating was performed for 5 days in an oven set at 60 ° C. Thereafter, the temperature was lowered to room temperature, and after the on-press development with the same printing machine and method as in the evaluation of the on-press developability, 500 sheets were printed. The 500th printed matter was visually confirmed, and the number of printing stains having a maximum diameter of 20 μm or more per 100 cm ² was calculated.
The number of pot-like stains per 100 cm ² is A less than 50, B more than 50 or less than 100, C less than 100 or more than 150, C less than 150 or less than 250. , E and 250 or more. The evaluation results are shown in Table 4 or Table 5. If the evaluation result is A, B, C or D, it can be evaluated as excellent in the suppression of the occurrence of a pot-like stain, preferably A, B or C, more preferably A or B, more preferably A It is further preferred that

(4) Evaluation of Surface State The coated state of the lithographic printing plate precursor before exposure which had been coated to the protective layer was visually observed. As a relative comparison, when the surface condition is relatively uniform (each layer is formed with a uniform thickness), unevenness is observed in the surface condition (coating unevenness is observed in at least one layer) C) when the surface of the lithographic printing plate precursor is not uniform), and B when it is in the state between A and C above. The evaluation results are shown in Table 4 or Table 5. If the evaluation result is A or B, it can be said that the surface condition of the surface of the lithographic printing plate precursor is excellent, and it is more preferably A.

From the results described in Table 4 or Table 5, it is found that the planographic printing plate precursor according to the present disclosure suppresses the occurrence of pot-like stains and is superior in surface planarity compared to the planographic printing plate precursor of the comparative example. Is clear. Furthermore, it is understood that the lithographic printing plate precursor according to the present disclosure is excellent in printing durability and on-press developability.

Moreover, the detail of each compound described in Table 4 or Table 5 except having mentioned above is shown below.

<Polymer particles>
G-1: The preparation of an image recording layer coating solution containing the following microgel (1) and polymer particles G-1 (microgel (1)) was carried out by mixing the components described in Table 4 or Table 5 other than the following microgel solution. The prepared photosensitive solution and the following microgel solution were prepared by mixing and stirring immediately before coating to obtain the composition described in Table 4 or Table 5.
G-2: The following polymer particle G-2
G-3: Styrene / acrylonitrile copolymer stabilized with an anionic wetting agent (molar ratio 50/50, average particle size 61 nm, solid content about 20%

[Preparation of microgel solution]
Microgel (1) (polymer particles G-1): 2.640 parts Distilled water: 2.425 parts

The preparation method of microgel (1) used for the said microgel liquid is shown below.

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

-Preparation of microgel (1)-
The following oil phase component and aqueous phase component were mixed, and emulsified using a homogenizer at 12,000 rpm for 10 minutes. After stirring the obtained emulsion at 45 ° C. for 4 hours, 10 mass of 1,8-diazabicyclo [5.4.0] undec-7-ene-octylate (U-CAT SA 102, manufactured by San Apro Ltd.) 5.20 g of% aqueous solution was added, it stirred at room temperature for 30 minutes, and left still at 45 degreeC for 24 hours. The solid content concentration was adjusted to 20% by mass with distilled water to obtain an aqueous dispersion of microgel (1). The average particle size was measured by a light scattering method and found to be 0.28 μm.

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

-Water phase composition-
Distilled water: 46.87g

[Preparation of aqueous dispersion of polymer particles G-2]
A 1000 ml four-necked flask is equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser, and nitrogen gas is introduced to perform deoxygenation while polyethylene glycol methyl ether methacrylate (PEGMA, average of ethylene glycol) Number of repeating units: 50) 10 g, 200 g of distilled water and 200 g of n-propanol were added, and the mixture was heated until the internal temperature reached 70.degree. Next, a mixture of 10 g of previously mixed styrene (St), 80 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, 0.4 g of 2,2'-azobisisobutyronitrile was added, and the internal temperature was raised to 80.degree. Subsequently, 0.5 g of 2,2'-azobisisobutyronitrile was added over 6 hours. The polymerization proceeded 98% or more at the stage of reaction for a total of 20 hours, and an aqueous dispersion (1) of polymer particles G-2 of PEGMA / St / AN = 10/10/80 by weight ratio was prepared . The particle size distribution of the polymer particles G-2 had a maximum value at a particle size of 150 nm.

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

<Binder polymer>
B-1a: Compound of the following structure B-1b: Compound of the following structure B-2: Compound of the following structure

In the above structural formula, the subscript of each structural unit represents the content (mol%) of each structural unit, and the subscript of the parenthesis indicating the oxyethylene unit represents the number of repetitions of the oxyethylene unit.
The halide ion in B-1b is derived from an ammonium halide compound used as a reaction catalyst when reacting a structural unit derived from methacrylic acid with glycidyl methacrylate.

<Polymerizable compound>
M-1: Tris (acryloyloxyethyl) isocyanurate, NK ester A-9300, Shin-Nakamura Chemical Co., Ltd. M-2: Dipentaerythritol pentaacrylate, SR-399, Sartomer M-3: Dipenta Erythritol hexaacrylate, A-DPH, Shin-Nakamura Chemical Co., Ltd. M-4: dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, UA-510H, Kyoeisha Chemical Co., Ltd. M-5: ethoxylated pentaerythritol Tetraacrylate, ATM-4E, Shin-Nakamura Chemical Co., Ltd. product

<Electron-accepting polymerization initiator>
I-1 to I-6: compounds of the following structures

The above structures, TsO ^- represents tosylate anion.

<Infrared absorber>
K-1 to K-5: compounds of the following structures

In the above structure, Ph represents a phenyl group.

<Electron donated polymerization initiator>
R-1: compound of the following structure

<Acid coloring agent>
H-1: S-205 (manufactured by Fukui Yamada Chemical Industry Co., Ltd.)
H-2: GN-169 (Yamamoto Kasei Co., Ltd.)
H-3: Black-XV (Yamamoto Kasei Co., Ltd.)
H-4: Red-40 (Yamamoto Kasei Co., Ltd.)

<Low Molecular Weight Hydrophilic Compound>
T-1: Tris (2-hydroxyethyl) isocyanurate T-2: Compound of the following structure T-3: Hydroxypropyl cellulose, Klucel M, manufactured by Hercules

<Sepetic agent>
C-1: Compound of the following structure C-2: Benzyldimethyloctyl ammonium, PF ₆ salt C-3: Compound of the following structure

<Surfactant>
W-1: Compound of the following structure

In the above structure, the subscript at the lower right of each parenthesis of each structural unit represents a content ratio (mass ratio).

<Solvent>
S-1: 2-butanone (MEK)
S-2: 1-Methoxy-2-propanol (MFG)
S-3: Methanol S-4: 1-Propanol S-5: Distilled water

The disclosure of Japanese Patent Application No. 2018-012410 filed Jan. 29, 2018 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are as specific and distinct as when individual documents, patent applications, and technical standards are incorporated by reference. Incorporated herein by reference.

Claims

An aluminum support,
An image recording layer formed on the aluminum support;
A lithographic printing plate precursor having a total content of halide ions relative to the total mass of all layers formed on the aluminum support of more than 0 ppm and not more than 1,000 ppm.
The lithographic printing plate precursor as claimed in claim 1, wherein the total content of the halide ions is more than 0 ppm and not more than 500 ppm.
In at least one layer among all the layers formed on the aluminum support, at least one selected from the group consisting of fluoride ion, chloride ion, bromide ion, and iodide ion as the halide ion The lithographic printing plate precursor as claimed in claim 1 or 2, which comprises one type.
The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein any of the layers formed on the aluminum support contains a halide of a quaternary ammonium cation.
The image recording layer contains an electron accepting polymerization initiator,
The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the electron accepting polymerization initiator is an iodonium salt.
The lithographic printing plate precursor as claimed in claim 5, wherein the iodonium salt is a compound represented by the following formula 1.

In Formula 1, Ar 1 and Ar 2 are benzene rings which may have a substituent, and the substituents of two benzene rings are different from each other, and at least one of the substituents of the benzene ring is A structure in which the sum of Hammett σ values is negative, Z − represents a counter anion.
The lithographic printing plate precursor as claimed in claim 5 or 6, wherein the iodonium salt is a compound represented by the following formula 1a.

In Formula 1a, Ar 1a is a benzene ring having a substituent, and the total sum of Hammett σ values of the substituents is negative, and Ar 2a is a benzene ring having a substituent, the substituent The sum of Hammett σ values of represents a positive one, and Z − represents a counter anion.
The lithographic printing plate precursor as claimed in claim 7, wherein the iodonium salt represented by the formula 1a is an iodonium salt represented by the following formula 2.

In the formula 2, R 1 to R 6 each independently represent a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a halogen atom, a haloalkyl group, a cyano group, a nitro group, -OR 7 , -OCOR 7 , -OCONR 7 R 8 , -OSO 2 R 7 , -OPO (OR 7 ) (OR 8 ), -OSi R 7 R 8 R 9 , -COR 7 , -COOR 7 , -CONR 7 R 8 , -NR 7 R 8, -NR 7 COR 8, -NR 7 COOR 8, -NR 7 CONR 8 R 9, -N (COR 7) (COR 8), - N + R 7 R 8 R 9 · Y -, -NR 7 SO 2 R 8 , -SR 7 , -SOR 7 , -SO 2 R 7 , -SO 3 R 7 , -SO 2 NR 7 R 8 , -PR 7 R 8 , -PO (OR 7 ) (OR 8 ), or represents -SiR 7 R 8 R 9 R 7 ~ R 9 are each independently a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, or an alkynyl group, Z - and Y - is, each independently represents a counter anion, R 1 ~ All of R 3 will not be hydrogen atoms, and all of R 4 to R 6 will not be hydrogen atoms.
The lithographic printing plate precursor as claimed in any one of claims 5 to 8, further comprising a borate compound as the electron donor polymerization initiator.
The lithographic printing plate precursor as claimed in claim 9, wherein the borate compound is a tetraphenyl borate compound.
The lithographic printing plate precursor as claimed in any one of claims 5 to 10, wherein the image recording layer further comprises an infrared absorber and a polymerizable compound.
The lithographic printing plate precursor as claimed in any one of claims 5 to 11, wherein the image recording layer comprises polymer particles.
The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the image recording layer comprises an infrared absorber and hydrophobic thermoplastic polymer particles.
The lithographic printing plate precursor according to any one of claims 1 to 13, which is a lithographic printing plate precursor for on-press development.
A step of imagewise exposing the lithographic printing plate precursor according to any one of claims 1 to 14;
A method of preparing a lithographic printing plate, comprising the step of removing the unexposed area of the image recording layer with at least one of printing ink and dampening water.