WO2020022071A1

WO2020022071A1 - Method for producing lithographic printing plate

Info

Publication number: WO2020022071A1
Application number: PCT/JP2019/027419
Authority: WO
Inventors: 康平會津; 侑也宮川; 因埜　紀文
Original assignee: 富士フイルム株式会社
Priority date: 2018-07-26
Filing date: 2019-07-10
Publication date: 2020-01-30

Abstract

A method for producing a lithographic printing plate comprises a step of exposing a lithographic printing original plate that includes an image-recording layer on a support, and a step of carrying out a development process using a developing solution having a pH of at least 10 but less than 12. The image-recording layer contains a binder having a constituent unit represented by formula (Bn), a photopolymerization initiator, and a polymerizable compound. The developing solution contains an amphoteric surfactant and a non-amphoteric surfactant. In formula (Bn), R₁ to R₃ each independently represent a hydrogen atom or an alkyl group; R₄ to R₈ each independently represent a hydrogen atom or a monovalent substituent; and L₁ represents a divalent linking group.

Description

How to make a lithographic printing plate

The present disclosure relates to a method for producing a lithographic printing plate.

In general, a lithographic printing plate is composed of an oleophilic image area that receives ink during a printing process and a hydrophilic non-image area that receives fountain solution. Lithographic printing utilizes the property that water and oil-based ink repel each other, so that 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). In this method, a difference in ink adhesion is caused on the surface of a lithographic printing plate, the ink is deposited only on an image portion, and then the ink is transferred to a printing medium such as paper for printing.
Conventionally, in order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) comprising a hydrophilic support and a lipophilic photosensitive resin layer (image recording layer) provided thereon is widely used. Usually, after the lithographic printing plate precursor is exposed through an original image such as a lithographic film, the image recording layer corresponding to the image portion is left, and the unnecessary image recording layer corresponding to the non-image portion is adjusted to pH 12 or more. A lithographic printing plate is obtained by performing plate making by dissolving and removing with a strong alkaline developer and exposing a hydrophilic support surface to form a non-image portion.

On the other hand, in recent years, digitization techniques for electronically processing, storing, and outputting image information with a computer have become widespread, and various new image output methods corresponding to such digitization techniques have been put to practical use. It is becoming. Along with this, digitized image information is carried on highly convergent radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with the light, and directly through the lithographic printing plate without passing through a lithographic film. The computer-to-plate (CTP) technology for manufacturing GaN has attracted attention. Therefore, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.
Solid-state lasers such as semiconductor lasers and YAG lasers that emit infrared light having a wavelength of 760 nm to 1,200 nm as laser light sources used in the above-described CTP technology have become available at low cost and with high output and small size. Very useful. Also, a UV laser can be used.

Further, as a conventional method for producing a lithographic printing plate, the methods described in Patent Documents 1 to 3 are known.
Patent Document 1 discloses a method for producing an image-formed lithographic printing plate, comprising (a) (i) a substrate having a hydrophilic surface, (ii) a radically polymerizable coating, and (iii) oxygen impermeable. A negative water-soluble or water-dispersible overcoat and a negative-working lithographic printing plate precursor comprising imagewise exposure to radiation to which the radically polymerizable coating is sensitive, (b) (i) water and (ii) ) At least one surfactant, (iii) at least one water-soluble, film-forming hydrophilic polymer, and (iv) at least one alkaline agent in an amount sufficient to obtain a pH of 9.5-14. A reagent and (v) one or more optionally selected from organic solvents, biocides, complexing agents, buffer substances, filter dyes, defoamers, anticorrosives and radical inhibitors An aqueous alkaline processing solution containing an additive, and an imagewise exposed precursor (C) removing excess treatment solution from the treated precursor obtained in step (b), (d) optionally drying, (e) optionally baking, f) placing the precursor obtained in step (c), (d) or (e) on a printing press, and then contacting it with a fountain solution and printing ink simultaneously or sequentially; However, provided that there is no washing step between any of the steps (a) to (f), that the step (c) is not a washing step, and that the step (c) There is described a method for producing an imaged lithographic printing plate, provided that there is no gumming step after b).
Patent Document 2 discloses that a photosensitive layer and a protective layer containing (A) a polymerization initiator, (B) a polymerizable compound, (C) a sensitizing dye, and (D) a binder polymer are formed on a hydrophilic support. A method of preparing a lithographic printing plate precursor, comprising: exposing a lithographic printing plate precursor having, in order, a laser exposure and then removing a protective layer and a photosensitive layer in a non-exposed portion in the presence of a developer. A method for preparing a lithographic printing plate is described, wherein the developer contains a surfactant and a nonionic surfactant having an alkylene oxide chain and has a pH of 2 to less than 10.
Patent Literature 3 discloses that a lithographic printing plate precursor having an image recording layer on a support having a surface subjected to a hydrophilic treatment and / or having an undercoat layer is cured by imagewise exposure. Then, in the method for processing a lithographic printing plate precursor, which is subjected to development with an aqueous solution having a pH of 2 to 10, the aqueous solution used for the development has an amphoteric surfactant and a fatty chain, and the total carbon number of the fatty chain is It has an anionic surfactant having 6 or more and an aromatic ring, and contains an anionic surfactant selected from an anionic surfactant having a total carbon number of 12 or more. A method for treating a lithographic printing plate precursor characterized in that the content is 0.1 to 3.3% by mass based on the entire aqueous solution is described.

Patent Document 1: JP-T-2009-540377 Patent Document 2: JP-A-2011-180291 Patent Document 3: JP-A-2009-86344

The problem to be solved by the embodiment of the present invention is to provide a method for producing a lithographic printing plate having excellent suppression of development sludge.

Means for solving the above problems include the following aspects.
<1> a step of exposing a lithographic printing plate precursor having an image recording layer on a support, and a step of performing a development treatment with a developer having a pH of 10 or more and less than 12; Lithographic printing comprising a binder having a constitutional unit represented by Bn), a photopolymerization initiator, and a polymerizable compound, wherein the developer contains an amphoteric surfactant and a surfactant other than the amphoteric surfactant. How to make a plate.

In the formula (Bn), R ₁ to R ₃ each independently represent a hydrogen atom or an alkyl group, R ₄ to R ₈ each independently represent a hydrogen atom or a monovalent substituent, and L ₁ represents a divalent Represents a linking group.

<2> The method for producing a lithographic printing plate according to <1>, wherein the exposing in the exposing step is performed by laser light having a wavelength of 760 nm to 1,200 nm.
<3> The method for producing a lithographic printing plate according to <1>, wherein the exposing in the exposing step is performed by a laser beam having a wavelength of 250 nm to 420 nm.
<4> The method for producing a lithographic printing plate according to any one of <1> to <3>, which does not include a step of washing the lithographic printing plate obtained by the developing treatment after the step of performing the developing treatment.
<5> The method for preparing a lithographic printing plate according to any one of <1> to <4>, wherein the amphoteric surfactant contains a compound represented by the following formula (I) or (II).

In the formulas (I) and (II), R ¹ to R ³ each independently represent an alkyl group, and an ester bond (— (C ＝ O) in the alkyl chain of the alkyl group in the above R ¹ to R ³ . O—), an ether bond (—O—), and an amide bond (—NH— (C ＝ O) —), and R ⁴ to R ⁶ may have a linking group. Each independently represents an alkyl group, and an ester bond (— (C ＝ O) O—), an ether bond (—O—), and an amide bond (in the alkyl chain of the alkyl group in R ⁴ to R ⁶ ) It may have a linking group selected from the group consisting of -NH- (C = O)-), L represents an alkylene group, and A represents a carboxylate ion or a sulfonate ion.

<6> The method for producing a lithographic printing plate according to <5>, wherein the amphoteric surfactant contains the compound represented by the formula (II).
<7> At least one of R ⁴ to R ⁶ has a linking group selected from the group consisting of an ester bond, an amide bond, and an ether bond in the alkyl chain of the alkyl group; <6> is a carboxylate ion.
<8> Any of <1> to <7>, wherein the surfactant other than the amphoteric surfactant is at least one surfactant selected from the group consisting of an anionic surfactant and a nonionic surfactant. The method for producing a lithographic printing plate according to any one of the first to third aspects.
<9> The anionic surfactant is a compound having an aromatic ring structure and at least one structure selected from the group consisting of a sulfonate structure, a carboxylate structure, and a phosphate structure. 8> The method for producing a lithographic printing plate described in <8>.
<10> The method for preparing a lithographic printing plate according to <9>, wherein the anionic surfactant is a compound represented by the following formula (III) or (IV).

In formulas (III) and ^{^{(IV), R An1 ~ R}} An10 each independently represent a hydrogen atom or an alkyl group, LAn is an integer of 1 ~ ^{3, X An 1} and ^{X An2} are each independently sulfone An acid base, a carboxylate group or a phosphate group, ^wherein the total number of carbon atoms of R ^An1 to R ^An5 is 3 or more, and the total number of carbon atoms of R ^An6 to R ^An10 is 3 or more.

<11> The method for producing a lithographic printing plate according to any one of <8> to <10>, wherein the nonionic surfactant is a compound having an aromatic ring structure and an alkyleneoxy chain structure.
<12> The method for preparing a lithographic printing plate according to <11>, wherein the nonionic surfactant is a compound represented by the following formula (V).
X ^No -Y ^No -O- (A ^No ) p- (B ^No ) qH (V)
In the formula (V), X ^No represents an aromatic group, Y ^No represents a single bond or an alkylene group having 1 to 10 carbon atoms, A ^No and B ^No are different groups, and —CH ₂ CH ₂ Represents O— or —CH ₂ CH (CH ₃ ) O—, p and q each independently represents an integer of 0 to 100, and the sum of p and q is 2 or more.
<13> The method for producing a lithographic printing plate according to any one of <1> to <12>, wherein the developer contains an organic solvent.
<14> The binder according to any one of <1> to <13>, wherein the binder further has a structural unit represented by the following formula (Ac) and a structural unit represented by the following formula (Al). How to make a lithographic printing plate.

In the formulas (Ac) and (Al), R ^Ac and R ^Al each independently represent a hydrogen atom or a methyl group.

According to the embodiment of the present invention, it is possible to provide a method for producing a lithographic printing plate excellent in suppressing development sludge.

FIG. 1 is a schematic configuration diagram of an automatic developing device that can be suitably used in a method of manufacturing a planographic printing plate according to the present disclosure. FIG. 1 is a diagram illustrating an example of a configuration of an automatic developing apparatus for one-bath processing that can be suitably used in a method of manufacturing a planographic printing plate according to the present disclosure.

Hereinafter, the content of the present disclosure will be described in detail. The description of the components described below may be made based on typical embodiments of the present disclosure, but the present disclosure is not limited to such embodiments.
In this specification, “to” indicating a numerical range is used to mean that the numerical values described before and after the numerical range are included as a lower limit and an upper limit.
In the numerical ranges described in stages in this specification, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of the numerical range described in other stages. Good. Further, in the numerical ranges described in this specification, the upper limit or the lower limit of the numerical ranges may be replaced with the values shown in the embodiments.
Further, in the notation of a group (atomic group) in this specification, the notation of not indicating substituted or unsubstituted includes not only a group having no substituent but also a group 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) acryl” is a term used in a concept including both acryl and methacryl, 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 even if it cannot be clearly distinguished from other steps, the term is used as long as the intended purpose of the step is achieved. included.
In the present disclosure, “mass%” and “wt%” have the same meaning, and “mass part” and “part by weight” have the same meaning.
Furthermore, in the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.
In addition, columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (all trade names manufactured by Tosoh Corporation) are used for the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present disclosure unless otherwise specified. It is a molecular weight detected by a gel permeation chromatography (GPC) analyzer using a solvent THF (tetrahydrofuran) and a differential refractometer and converted using polystyrene as a standard substance.
In this specification, the term “lithographic printing plate precursor” includes not only the lithographic printing plate precursor but also a discarded plate precursor. Further, the term “lithographic printing plate” includes not only a lithographic printing plate precursor but also a lithographic printing plate produced through operations such as exposure and development, if necessary, as well as a discarded plate. In the case of a discarded plate master, the operations of exposure and development are not necessarily required. The discarded plate is a lithographic printing plate precursor to be attached to an unused plate cylinder, for example, when printing a part of the paper surface in monochrome or two colors in color newspaper printing.
Hereinafter, the present disclosure will be described in detail.

(How to make a lithographic printing plate)
The method for preparing a lithographic printing plate according to the present disclosure includes a step of exposing a lithographic printing plate precursor having an image recording layer on a support (hereinafter, also referred to as an “exposure step”), and a pH of from 10 to less than 12. The image recording layer includes a step of performing a development treatment with a developer (hereinafter, also referred to as a “development step”). The image recording layer includes a binder having a structural unit represented by the following formula (Bn), a photopolymerization initiator, and It contains a polymerizable compound, and the developer contains an amphoteric surfactant and a surfactant other than the amphoteric surfactant.

When a lithographic printing plate precursor having an image recording layer containing a binder having a structural unit represented by the formula (Bn) is developed, the image recording layer components after the development and removal are agglomerated and settled in a developing solution, called sludge called development sludge. The present inventors have found that a large amount of deposits may occur.
The present inventors presume that the aromatic ring structures in the structural unit represented by the formula (Bn) are likely to aggregate with each other due to the π-π interaction, so that a large amount of development sludge is generated. I have.
As a result of intensive studies by the present inventors, it has been found that the above configuration can provide a method for producing a lithographic printing plate having excellent suppression of development sludge.
The action mechanism of the excellent effect by the above configuration is not clear, but is estimated as follows.
As a result of extensive studies by the present inventors, the pH of a developer containing an amphoteric surfactant and a surfactant other than the amphoteric surfactant of 10 or more and less than 12 is used to develop the developer. In the pH range, it is considered that the amphoteric surfactant and the surfactant other than the amphoteric surfactant act in concert to suppress aggregation and sedimentation of the image recording layer components after the development is removed, and are excellent in suppressing the development sludge. Can be

Further, in the method for producing a lithographic printing plate according to the present disclosure, since the amphoteric surfactant has an antistatic effect, the friction coefficient is increased by the fact that the developer containing the amphoteric surfactant adheres to the surface of the non-image portion after the development processing. It is presumed that the density of the non-image portion is reduced, and the non-image portion is less likely to be scratched.

<Exposure process>
The method for preparing a lithographic printing plate according to the present disclosure includes a step of exposing a lithographic printing plate precursor having an image recording layer on a support (exposure step), and the image recording layer is represented by the following formula (Bn). And a photopolymerization initiator and a polymerizable compound.
Prior to the development step, the exposure step is performed. In the exposure step, it is preferable to expose the lithographic printing plate precursor through a transparent original having a line image, a halftone dot image, or the like, or to imagewise expose by laser beam scanning using digital data.
The “image” in the present disclosure is a concept that includes not only images in a narrow sense, such as figures and pictorial photographs, but also characters, numbers, and symbols, and includes an image in which these are mixed.
Light sources suitable for the exposure include a carbon arc lamp, a mercury lamp, a xenon lamp, a metal halide lamp, a strobe, a light emitting diode (LED), a laser beam, and the like. Laser light is particularly preferable, and solid-state lasers and semiconductor lasers that emit infrared light with a wavelength of 760 nm to 1,200 nm, ultraviolet semiconductor lasers that emit light with a wavelength of 250 nm to 420 nm, argon ion lasers that emit visible light, and FD (Frequency Doubled) —YAG (Yttrium Aluminum Garnet) laser and the like. Above all, the exposure in the exposure step is preferably performed with a laser beam having a wavelength of 760 nm to 1,200 nm from the viewpoint of simplification of plate making, and a laser having a wavelength of 250 nm to 420 nm from the viewpoint of resolution. It is preferable to use light.
In addition, from the viewpoint of simplification of plate making, a laser that emits infrared light capable of performing work under a white light or a yellow light is preferable.
Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 μs, and the irradiation energy amount is 10 mJ / cm ² to 300 mJ / cm ^2. preferable. It is preferable to use a multi-beam laser device to shorten the exposure time.

<< Lithographic printing plate precursor >>
The lithographic printing plate precursor used in the present disclosure is a negative-type image forming method in which an image-exposed region is cured to form an image portion, and an unexposed portion is removed by a development process as described above to form a non-image portion. Has ability. In the present disclosure, "having an image recording layer on a support" means that, even if the image recording layer is provided directly on the support, another layer is provided between the support and the image recording layer. May be provided, and this does not deny the existence of optional layers such as a protective layer, an undercoat layer, an intermediate layer, and a back coat layer which are optionally provided in the lithographic printing plate precursor.

(Image recording layer)
The image recording layer in the lithographic printing plate precursor used in the present disclosure includes a binder having a structural unit represented by the above formula (Bn), a photopolymerization initiator, and a polymerizable compound.
The image recording layer is preferably an infrared-sensitive image recording layer.
Further, the image recording layer is infrared-sensitive and more preferably contains at least a triphenylalkyl borate salt compound or a tetraphenyl borate salt compound, and further preferably further contains a copper phthalocyanine pigment.
It is more preferable that the image recording layer is sensitive to infrared light, does not contain a borate salt, and contains a coloring dye.
It is particularly preferable that these infrared-sensitive image recording layers contain a cyanine dye and an iodonium salt.
Hereinafter, each component contained in the image recording layer will be sequentially described.

-Binder having structural unit represented by formula (Bn)-
The image recording layer contains a binder having a structural unit represented by the following formula (Bn).

R ₁ and R ₂ in Formula (Bn) are each independently preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.
R ₃ in the formula (Bn) is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and more preferably a hydrogen atom or a methyl group, from the viewpoint of scratch resistance and printing durability.
Examples of the monovalent substituent for R ₄ to R ₈ in the formula (Bn) include an alkyl group, an alkoxy group, an aryl group, a halogen atom, an acyloxy group, an alkoxycarbonyl group, a carboxy group, a hydroxy group, and Examples include groups in which a hydrogen atom is further substituted with one or more of these groups.
Above all, the monovalent substituent is preferably an alkyl group, an alkoxy group, a halogen atom, a carboxy group, or a hydroxy group, and more preferably an alkyl group, from the viewpoint of scratch resistance.
The carbon number of R ₄ to R ₈ in the formula (Bn) is preferably from 0 to 20, more preferably from 0 to 8, and even more preferably from 0 to 4.
R ₄ to R ₈ in the formula (Bn) are each independently preferably a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a carboxy group, or a hydroxy group from the viewpoint of scratch resistance and printing durability. It is more preferably a hydrogen atom or an alkyl group, and particularly preferably a hydrogen atom.
L in the formula (Bn) represents an alkylene group or an alkylene group, an ester bond (— (C ＝ O) O—), an ether bond (—O—), and an amide from the viewpoint of scratch resistance and printing durability. It is preferably a group obtained by combining two or more groups selected from the group consisting of a bond (—NH— (C ＝ O) —), more preferably an alkylene group, and more preferably an alkylene group having 1 to 8 carbon atoms. More preferably, it is particularly preferably a methylene group.

The structural unit represented by the formula (Bn) preferably contains a structural unit represented by the following formula (Bn-1) from the viewpoint of development sludge suppression, scratch resistance and printing durability. More preferably, it is a structural unit represented by Bn-1).

In the formula (Bn-1), R ₉ represents a hydrogen atom or an alkyl group.

R ₉ in the formula (Bn-1) is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and more preferably a hydrogen atom or a methyl group, from the viewpoint of scratch resistance and printing durability.

具体 Specific examples of the structural unit represented by the above formula (Bn) include preferably the following structural units, but needless to say, the present invention is not limited thereto.

The binder having the structural unit represented by the above formula (Bn) may have one kind of the structural unit represented by the above formula (Bn) alone, or may have two or more kinds thereof.
The content of the structural unit represented by the formula (Bn) in the binder having the structural unit represented by the formula (Bn) is determined from the viewpoint of the development sludge suppression, scratch resistance and printing durability from the viewpoint of the formula (Bn). ), Preferably 5 to 90% by mass, more preferably 10 to 80% by mass, and more preferably 15 to 75% by mass based on the total mass of the binder having the structural unit represented by the formula (1). Is more preferable, and particularly preferably 20 to 50% by mass.

As long as the binder having the structural unit represented by the formula (Bn) contains the structural unit represented by the formula (Bn), the remaining structural unit may be a structural unit derived from any monomer. The details are preferably monomer units (structural units) used in an acrylic resin described in detail in other binder polymers described below.
Specifically, it is formed from one or more of (meth) acrylic acid, (meth) acrylate ((meth) acrylate), acrylonitrile, styrene and styrene derivatives, and poly (alkylene glycol) (meth) acrylate Preferred are those containing the structural units described above.
Further, the binder having the structural unit represented by the above formula (Bn) is preferably an acrylic resin. Note that the acrylic resin refers to a structural unit derived from at least one compound selected from the group consisting of a (meth) acrylate compound, a (meth) acrylamide compound, and (meth) acrylic acid, based on the total mass of the resin. It is assumed that the polymer has 50% by mass or more.

The binder having the structural unit represented by the formula (Bn) is a hydrophilic group as a structural unit (other structural unit) other than the structural unit represented by the formula (Bn) from the viewpoint of developability. It is preferable to further include a structural unit having the following formula, and it is more preferable to further include a structural unit derived from (meth) acrylic acid (a structural unit represented by the following formula (Ac)).
As the hydrophilic group, a carboxy group or a hydroxy group is preferably mentioned, and a carboxy group is more preferably mentioned.

In the formula (Ac), R ^Ac represents a hydrogen atom or a methyl group.

The binder having a structural unit represented by the above formula (Bn) may have a single structural unit having a hydrophilic group, or may have two or more structural units.
The content of the structural unit having a hydrophilic group in the binder having the structural unit represented by the formula (Bn) is determined based on the total mass of the binder having the structural unit represented by the formula (Bn) from the viewpoint of developability. On the other hand, it is preferably 1% by mass to 80% by mass, more preferably 5% by mass to 50% by mass, and particularly preferably 15% by mass to 35% by mass.

Further, from the viewpoint of printing durability, the binder having the structural unit represented by the above formula (Bn) has an ethylenic property as a structural unit other than the structural unit represented by the above formula (Bn) (other structural units). It is preferable to further have a structural unit having an unsaturated group, and it is more preferable that it further has a structural unit represented by the following formula (Al). It is particularly preferable to further include a structural unit represented by the following formula (Al) and a structural unit represented by the following formula (Al).
The ethylenically unsaturated group in the constitutional unit having an ethylenically unsaturated group is not particularly limited from the viewpoint of printing durability, but may be an allyl group, a (meth) acryloxy group, a (meth) acrylamide group, or a vinyl ester. Groups, vinyl ether groups or styryl groups (vinylphenyl groups) are preferred, allyl groups or (meth) acryloxy groups are more preferred, and allyl groups are particularly preferred.

In the formula (Al), R ^Al represents a hydrogen atom or a methyl group.

The binder having a structural unit represented by the above formula (Bn) may have a single structural unit having an ethylenically unsaturated group, or may have two or more structural units.
The content of the constituent unit having an ethylenically unsaturated group in the binder having the constituent unit represented by the above formula (Bn) is determined from the viewpoint of developability of the binder having the constituent unit represented by the above formula (Bn). It is preferably from 10% by mass to 70% by mass, more preferably from 20% by mass to 60% by mass, and particularly preferably from 30% by mass to 50% by mass, based on the total mass.

The binder having a structural unit represented by the above formula (Bn) that can be used in the present disclosure has a weight average molecular weight (Mw) of preferably 2,000 to 1,000,000, and 10,000 to 200. , More preferably 20,000 to 100,000. The acid value of the binder having the structural unit represented by the above formula (Bn) is preferably from 20 mgKOH / g to 400 mgKOH / g, as determined using a known method.

The image recording layer may contain one kind of a binder having a structural unit represented by the above formula (Bn), or may contain two or more kinds of binders.
The content of the binder having the structural unit represented by the above formula (Bn) is preferably from 10% by mass to 70% by mass, and more preferably from 20% by mass to 50% by mass, based on the total mass of the image recording layer. Is more preferable.

-Photopolymerization initiator-
The image recording layer contains a photopolymerization initiator.
As the photopolymerization initiator, a photoradical polymerization initiator is preferably used.

As the photopolymerization initiator, those known to those skilled in the art can be used without limitation. Specifically, for example, trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexa Examples include an arylbiimidazole compound, an organic boron compound, a disulfone compound, an oxime ester compound, an onium salt compound, and an iron arene complex. Among them, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds and metallocene compounds is preferable, and hexaarylbiimidazole compounds or onium salt compounds are particularly preferable. Two or more photopolymerization initiators can be used in combination as appropriate.

Hexaarylbiimidazole compounds include lophin dimers, for example, 2,2 described in European Patent Nos. 24,629, 107,792 and 4,410,621. '-Bis (o-chlorophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbi Imidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5 5′-tetra (m-methoxyphenyl) biimidazole, 2,2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis ( o-nitrophenyl) -4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-tri Fluoromethylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.
The hexaarylbiimidazole compound is particularly preferably used in combination with a sensitizing dye having a maximum absorption at a wavelength of 250 nm to 420 nm.

Onium salt compounds suitably used in the present disclosure (in the present disclosure, function not as an acid generator but as an ionic polymerization initiator) are represented by the following formulas (RI-I) to (RI-III). The sulfonium salt compound, iodonium salt compound or diazonium salt compound represented. Particularly, a diaryliodonium salt compound or a triarylsulfonium salt compound is preferably used. The onium salt compound is particularly preferably used in combination with an infrared absorber having a maximum absorption at a wavelength of 760 nm to 1,200 nm.

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents. Preferred substituents are an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, An aryloxy group having 6 to 12 carbon atoms, a halogen atom, an alkylamino group having 1 to 12 carbon atoms, a dialkylamino group having 2 to 12 carbon atoms, an alkylamide or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxy group Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 6 to 12 carbon atoms.
Z ₁₁ ^- represents a monovalent anion. Specifically, halide ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, triphenylalkylborate ion, tetraphenylborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, and sulfuric acid Ions. Among them, from the viewpoint of stability, a perchlorate ion, a hexafluorophosphate ion, a tetrafluoroborate ion, a sulfonate ion, or a sulfinate ion is preferable, and from the viewpoint of increasing sensitivity, a triphenylalkylborate ion or Phenyl borate ions are preferred.

In the formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents. Preferred substituents are an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, An aryloxy group having 6 to 12 carbon atoms, a halogen atom, an alkylamino group having 1 to 12 carbon atoms, a dialkylamino group having 2 to 12 carbon atoms, an alkylamide or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxy group Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 6 to 12 carbon atoms.
Z ₂₁ ^- represents a monovalent anion. Specific examples include halide ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, and carboxylate ion. Among them, from the viewpoint of stability and reactivity, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, triphenylalkylborate ion, tetraphenylborate ion, sulfonate ion, sulfinate ion, or carboxylate ion Is preferable, and a triphenylalkyl borate ion or a tetraphenyl borate ion is particularly preferable from the viewpoint of increasing sensitivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ each independently represent an aryl group, an alkyl group, an alkenyl group having 20 or less carbon atoms which may have 1 to 6 substituents, or Represents an alkynyl group. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, An aryloxy group having 6 to 12 carbon atoms, a halogen atom, an alkylamino group having 1 to 12 carbon atoms, a dialkylamino group having 2 to 12 carbon atoms, an alkylamide or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxy group Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 6 to 12 carbon atoms.
Z ₃₁ ^- represents a monovalent anion. Specific examples include halide ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, and carboxylate ion. Among them, from the viewpoint of stability and reactivity, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, triphenylalkylborate ion, tetraphenylborate ion, sulfonate ion, sulfinate ion, or carboxylate ion Preferably, a triphenylalkyl borate ion or a tetraphenyl borate ion is particularly preferable from the viewpoint of increasing the sensitivity.
Further, carboxylate ions described in JP-A-2001-343742 and carboxylate ions described in JP-A-2002-148790 are also preferably used.
The onium salt compound is particularly preferably used in combination with an infrared absorber having a maximum absorption at a wavelength of 760 nm to 1,200 nm.

In addition, JP-A-2007-171406, JP-A-2007-206216, JP-A-2007-206217, JP-A-2007-225701, JP-A-2007-225702, JP-A-2007-316582, and JP-A-2007-328243 The polymerization initiators described in the above publications can be preferably used.

The photopolymerization initiator is suitably used alone or in combination of two or more.
In particular, in the present disclosure, the image recording layer is infrared-sensitive, and preferably contains at least one compound selected from the group consisting of a triphenylalkyl borate salt compound and a tetraphenyl borate salt compound. And a triphenylalkyl borate salt compound or a tetraphenyl borate salt compound. By adopting such an embodiment, sensitivity and printing durability are improved.
The content of the photopolymerization initiator in the image recording layer is preferably 0.01% by mass to 20% by mass, and more preferably 0.1% by mass to 15% by mass, based on the total mass of the image recording layer. Is more preferable, and the content is more preferably 1.0% by mass to 10% by mass.

-Polymerizable compound-
The image recording layer contains a polymerizable compound.
The polymerizable compound that can be used in the present disclosure is an addition polymerizable compound having at least one ethylenically unsaturated group, and is preferably a compound having at least one terminal ethylenically unsaturated group, and is preferably two compounds. It is more preferable that the compound has the above. Such compounds are widely known in the industrial field, and in the present disclosure, they can be used without any particular limitation. These have chemical forms such as, for example, monomers, prepolymers, ie, dimers, trimers and oligomers, or copolymers thereof, and mixtures thereof.

Examples of the monomer include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and esters and amides thereof. Esters of acids and aliphatic polyhydric alcohol compounds and amides of unsaturated carboxylic acids and aliphatic polyamine compounds are used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group or an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or an epoxy, and a monofunctional or Dehydration condensation products with polyfunctional carboxylic acids are also preferably used. Further, an isocyanate group, or an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group with a monofunctional or polyfunctional alcohol, amine, or thiol, and further, a halogeno group or And unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group and monofunctional or polyfunctional alcohols, amines and thiols. As another example, it is also possible to use a group of compounds in which unsaturated phosphonic acid, styrene, vinyl ether or the like is substituted for the above unsaturated carboxylic acid.

These are described in JP-T-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, and JP-A-9-179297. JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, and And Japanese Patent Application Laid-Open No. 10-333321.

Specific examples of the ester monomer of the polyhydric alcohol compound and the unsaturated carboxylic acid include acrylates such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol diacrylate. Propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetra Ethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, Antaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, isocyanurate ethylene oxide (EO) modified tri Acrylates, polyester acrylate oligomers and the like can be mentioned.

Examples of the methacrylate include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxyp Epoxy) phenyl] dimethyl methane, bis [p- (methacryloxyethoxy) phenyl] dimethyl methane, and the like.

Examples of itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, and pentaerythritol diitaconate. And sorbitol tetritaconate.
Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, sorbitol tetradicrotonate, and the like.
Examples of the isocrotonic acid ester include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.
Examples of the maleic acid ester include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

Examples of other esters include aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, and JP-A-59-5241. And those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used.
The above ester monomers can also be used as a mixture of two or more.

Specific examples of the monomer of the amide of the aliphatic polyamine compound and the unsaturated carboxylic acid include methylenebisacrylamide, methylenebismethacrylamide, 1,6-hexamethylenebisacrylamide, and 1,6-hexamethylenebismethacryl. Examples include amide, diethylenetriaminetrisacrylamide, xylylenebisacrylamide, and xylylenebismethacrylamide.
Examples of other preferred amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

Further, urethane-based addition-polymerizable compounds produced by using an addition reaction between an isocyanate group and a hydroxy group are also suitable, and such specific examples are described in, for example, JP-B-48-41708. A polyisocyanate compound having two or more isocyanate groups in one molecule and a vinyl monomer having a hydroxy group represented by the following formula (ii) added to a vinyl having two or more polymerizable vinyl groups in one molecule: Urethane compounds and the like.
CH ₂ ＣC (R ^4m ) COOCH ₂ CH (R ^5m ) OH Formula (ii)
(However, R ^4m and R ^5m each independently represent H or CH _3. )

Also, urethane acrylates described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-A-2003-344997, and JP-A-2006-65210. And JP-B-58-49860, JP-B-56-17654, JP-B-62-39417, JP-B-62-39418, JP-A-2000-250211, and JP-A-2007-94138. Urethane compounds having an ethylene oxide skeleton described in US Pat. No. 7,153,632, JP-A-8-505958, JP-A-2007-293221, and JP-A-2007-293223. Urethane compounds having a hydrophilic group are also suitable. Further, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277563, JP-A-63-260909 and JP-A-1-105238 are used. Depending on the case, an image recording layer having a very high photosensitive speed can be obtained.

In addition, the method of using the polymerizable compound can be arbitrarily selected from the viewpoints of the degree of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface tackiness, etc. Depending on the case, a layer configuration and a coating method such as undercoating and overcoating may be performed.

Details of the method of using these polymerizable compounds, such as the structure, whether they are used alone or in combination, and the amount added, can be arbitrarily set in accordance with the performance design of the final lithographic printing plate precursor.
The content of the polymerizable compound in the image recording layer is preferably 5% by mass to 75% by mass, more preferably 25% by mass to 70% by mass, and particularly preferably 30% by mass, based on the total mass of the image recording layer. In the range of ～ 60% by mass.

-Sensitizing dye-
The image recording layer preferably further contains a sensitizing dye. The sensitizing dye absorbs light at the time of image exposure to be in an excited state, and provides electron transfer, energy transfer or heat generation to the above-mentioned photopolymerization initiator, and provides energy by heating or the like. It can be used without limitation. In particular, a sensitizing dye having a maximum absorption at a wavelength of 250 nm to 420 nm or 760 nm to 1,200 nm is preferably used.

Examples of the sensitizing dye having the maximum absorption in the wavelength range of 250 nm to 420 nm include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, anthracenes, styryls, oxazoles, and the like.

Among the sensitizing dyes having an absorption maximum in the wavelength range of 250 nm to 420 nm, a preferable dye from the viewpoint of high sensitivity is a dye represented by the following formula (C).

In the formula (C), A ^1C represents an aryl group or a heteroaryl group which may have a substituent, and X ^1C represents an oxygen atom, a sulfur atom or N- (R ^3C ). R ^1C , R ^2C and R ^3C each independently represent a monovalent nonmetallic atomic group, and A ^1C and R ^1C and R ^2C and R ^3C are respectively bonded to each other to form an aliphatic or aromatic ring. May be formed.

Formula (C) will be described in more detail. R ^1C , R ^2C and R ^3C are each independently a monovalent nonmetallic atomic group, preferably a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted Represents an aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxy group, or a halogen atom.
Specific examples of preferred aryl groups for R ^1C , R ^2C and R ^3C include an aromatic group, a group in which one to three benzene rings form a condensed ring, and a condensed ring in which a benzene ring and a 5-membered unsaturated ring are condensed rings. Can be mentioned. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group. Among them, a phenyl group or a naphthyl group is more preferred. These may further be condensed with a heteroaromatic ring, and may further have a substituent.
As the heteroaryl group preferable as R ^1C , R ^2C and R ^3C , a monocyclic or polycyclic heteroaromatic group having at least one of a nitrogen atom, an oxygen atom and a sulfur atom is used. Examples include, for example, thiophene, thiazulene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indoyl, Indazole, purine, quinolizine, isoquinoline, phthalazine, naphthyridine, quinazoline, sinoline, pteridine, carbazole, carboline, phenanthrin, acridine, perimidine, phenanthroline, phthalazine, fenalzazine, fumaridine Examples thereof include groups obtained by removing one hydrogen atom from a heteroaromatic ring compound such as enoxazine, furazane, and phenoxazine. These may further be condensed with an aromatic ring, and may have a substituent.

Next, a description will be given ^{A 1C} in formula (C). A ^1C represents an aryl group or a heteroaryl group which may have a substituent, and specific examples of the aryl group or the heteroaryl group which may have a substituent include R ^1C and R ¹ in the formula (C). ^The same as those described for ^2C and R ^3C can be mentioned.

Specific examples of such a sensitizing dye include paragraphs 0047 to 0053 of JP-A-2007-58170, paragraphs 0036 to 0037 of JP-A-2007-93866, and paragraphs 0042 to 0047 of JP-A-2007-72816. Are preferably used.

Also, JP-A-2006-189604, JP-A-2007-171406, JP-A-2007-206216, JP-A-2007-206217, JP-A-2007-225701, JP-A-2007-225702, and JP-A-2007-316582 And sensitizing dyes described in JP-A-2007-328243 can also be preferably used.

Subsequently, a sensitizing dye having a maximum absorption at a wavelength of 750 nm to 1,400 nm, preferably 760 nm to 1,200 nm, which is suitably used in the present disclosure (hereinafter, may be referred to as an “infrared absorbing agent”) is described in detail. Will be described. Dyes or pigments are preferably used as the infrared absorber.

As the dye, commercially available dyes and known dyes described in literatures such as “Dye Handbook” (edited by the Society of Synthetic Organic Chemistry, Japan, 1970) can be used. Specifically, azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, dyes such as metal thiolate complexes Is mentioned.
Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, a cyanine dye or an indolenine cyanine dye is preferable, and a particularly preferable example is a cyanine dye represented by the following formula (a).

In the formula (a), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , —X ² -L ¹ or a group shown below. Here, Ph represents a phenyl group, X ² represents an oxygen atom, a nitrogen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms (the number of carbon atoms) and a hetero atom (N, S, An aryl group having O, a halogen atom, Se) and a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. X _a ^- is Z _a which will be described below ^- has the same definition as, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group and substituted amino group and a halogen atom.

R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the viewpoint of storage stability of the coating solution for the image recording layer, it is preferable that R ¹ and R ² are each independently a hydrocarbon group having 2 or more carbon atoms. R ¹ and R ² may be connected to each other to form a ring, and when forming a ring, it is particularly preferable to form a 5- or 6-membered ring.

Ar ¹ and Ar ² may be the same or different, and represent an aryl group which may have a substituent. Preferred aryl groups include a benzene ring and a naphthalene ring. Preferred substituents include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, and an alkoxy group having 12 or less carbon atoms. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different, and represent a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include an alkoxy group having 12 or less carbon atoms, a carboxyl group, and a sulfo group.
R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represent a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the viewpoint of availability of raw materials, a hydrogen atom is preferable. Furthermore, Za ^- represents a counter anion. However, when the cyanine dye represented by formula (a) has an anionic substituent in its structure and does not require charge neutralization, Za ^- is not necessary. Desirable Za ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, or a sulfonate ion from the viewpoint of storage stability of the coating solution for the image recording layer, and particularly preferably perchloric acid. Ion, hexafluorophosphate ion, or arylsulfonate ion. From the viewpoint of increasing the sensitivity, a triphenylalkyl borate ion or a tetraphenyl borate ion is also preferably used. In addition, a counter ion containing no halide ion is particularly preferable.

Specific examples of the cyanine dye represented by the formula (a) that can be suitably used include the compounds described in paragraphs 0017 to 0019 of JP-A-2001-133969, and the compounds described in paragraphs 0016 to 0016 of JP-A-2002-023360. Compounds described in paragraphs 0012 to 0037 of JP-A-2002-040638, preferably compounds described in paragraphs 0034 to 0041 of JP-A-2002-278057 and paragraphs 0080 to 008 of JP-A-2008-195018 And most preferably, compounds described in paragraphs 0035 to 0043 of JP-A-2007-90850.

Also, compounds described in paragraphs 0008 to 0009 of JP-A-5-5005 and paragraphs 0022 to 0025 of JP-A-2001-222101 can be preferably used.

In the present disclosure, it is preferable to use a water-soluble cyanine dye as the sensitizing dye.
Examples of the water-soluble cyanine dye include those described in JP-A-2004-351823, and a sulfonic acid group and / or a salt thereof, a phosphonic acid group and / or a salt thereof as a hydrophilic group in the molecule. , A carboxylic acid group and / or a salt thereof, and a hydroxy group.
Among them, it is more preferable that the compound has two or more sulfonic acid groups and / or salts thereof and phosphonic acid groups and / or salts thereof in the molecule, and the counter ion is an inorganic ion.

において In the present disclosure, an embodiment containing a cyanine dye as a sensitizing dye and further containing an iodonium salt compound is preferable. With such a configuration, sensitivity and printing durability are improved.

は Further, as the sensitizing dye, one kind may be used alone, or two or more kinds may be used in combination. An infrared absorber such as a pigment may be used in combination. As the pigment, compounds described in paragraphs 0072 to 0076 of JP-A-2008-195018 are preferable.

Examples of pigments include commercially available pigments, Color Index (C.I.) Handbook, "Latest Pigment Handbook" (edited by Japan Pigment Technical Association, 1977), "Latest Pigment Application Technology" (CMC Publishing, 1986), Pigments described in "Printing Ink Technology" published by CMC, 1984) can be used.

種類 The types of pigments include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and polymer-bound pigments. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Among these pigments, preferred is carbon black.

These pigments may be used without surface treatment, or may be used after surface treatment. Examples of the surface treatment include a method of surface coating a resin or wax, a method of attaching a surfactant, and a method of bonding a reactive substance (eg, a silane coupling agent, an epoxy compound, a polyisocyanate, etc.) to the pigment surface. Can be considered. The above surface treatment methods are described in “Properties and Applications of Metallic Soap” (Koshobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). I have.

(4) The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. When the content is in the above range, excellent dispersion stability of the pigment in the image recording layer is obtained, and a uniform image recording layer is obtained.

公知 As a method of dispersing the pigment, a known dispersion technique used for ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

The preferable addition amount of these sensitizing dyes is preferably 0.05% by mass to 30% by mass, more preferably 0.1% by mass to 20% by mass, and still more preferably 0.2% by mass, based on the total mass of the image recording layer. The range is from 10% by mass to 10% by mass.

The sensitizing dye may be added to the same layer as the other components, or may be added to a separate layer.

－Other binders－
The image recording layer may contain a binder (other binder) other than the binder having the structural unit represented by the formula (Bn).
As the other binder, any of various polymers known in the art to be used in the image recording layer of the negative working lithographic printing plate precursor can be used without limitation.
The weight average molecular weight of the other binder is preferably from 2,000 to 1,000,000, and more preferably from 10,000 to 200,000. The acid value of the other binder is preferably from 20 mgKOH / g to 400 mgKOH / g, as determined using a known method.

The other binder is preferably insoluble in water and soluble in an alkaline developer commonly used in a method for preparing a lithographic printing plate. Examples of such binders include, for example, EP 1,182,033 and US Pat. Nos. 6,309,792, 6,352,812, 6,569,603 and 6,893. No., 797,797, etc., polymers derived from (meth) acrylic acid and (meth) acrylate, polyvinyl acetal, phenolic resins, styrene and its derivatives, (meth) Examples include, but are not limited to, polymers derived from acrylonitrile, N-substituted cyclic imides, or maleic anhydride. Having pendant vinyl groups such as those described in U.S. Patent Nos. 6,899,994 and 4,511,645, and EP 1,182,033. Polymers are also useful.

The other binder is preferably a binder polymer having a hydrophobic skeleton and containing both of the following structural units a) and b) or only the structural repeating unit b).
a) a structural unit having a pendant cyano group directly bonded to a hydrophobic skeleton, and
b) A structural unit having a pendant group comprising a poly (alkylene oxide) segment.
The binder polymer has a poly (alkyleneoxy) segment, preferably a poly (ethyleneoxy) segment. The binder polymer may be a graft copolymer having a main chain polymer and a poly (alkylene oxide) side chain, or a block copolymer having a block of a (alkyleneoxy) -containing structural unit and a block of a non (alkyleneoxy) -containing repeating unit. . Both the graft copolymer and the block copolymer may further have pendant cyano groups bonded directly to the hydrophobic backbone. The alkyleneoxy group in the polyalkyleneoxy structural unit is preferably an alkyleneoxy group having 2 to 6 carbon atoms, more preferably an alkyleneoxy group having 2 or 3 carbon atoms. The alkylene moiety may be linear, branched, or a substituted product thereof. Poly (ethylene oxide) and poly (propylene oxide) segments are preferred, with poly (ethylene oxide) segments being most preferred.

Further, the binder polymer may include only a structural unit including a poly (alkyleneoxy) segment, and the binder polymer may be directly bonded to a structural unit having a poly (alkyleneoxy) segment and a hydrophobic skeleton. And a structural unit having a pendant cyano group. By way of example only, the structural unit may have a pendant group comprising a cyano, cyano substituted or cyano terminal alkylene group. Also, such structural units can be derived from ethylenically unsaturated monomers such as, for example, acrylonitrile, methacrylonitrile, methyl cyanoacrylate, ethyl cyanoacrylate, or combinations thereof. However, cyano groups can be introduced into the polymer by other conventional means. Examples of such cyano group-containing binder polymers are described in, for example, US Patent Application Publication No. 2005/003285.

By way of example, other binders can be formed by polymerization of combinations or mixtures of the following suitable ethylenically unsaturated monomers or macromers.
A) acrylonitrile, methacrylonitrile or a combination thereof,
B) poly (alkyleneoxy) esters of acrylic acid or methacrylic acid, such as poly (ethylene glycol) methyl ether acrylate, poly (ethylene glycol) methyl ether methacrylate or combinations thereof, and
C) If necessary, a monomer such as acrylic acid, methacrylic acid, styrene, hydroxystyrene, acrylate ester, methacrylate ester, acrylamide, methacrylamide, or a combination of such monomers.

The amount of the poly (alkyleneoxy) segment in the other binder is preferably 0.5% by mass to 60% by mass, more preferably 2% by mass to 50% by mass, and 5% by mass to 40% by mass. %, More preferably 5 to 20% by mass. The amount of the (alkyleneoxy) segment in the block copolymer is preferably from 5% by mass to 60% by mass, more preferably from 10% by mass to 50% by mass, and preferably from 10% by mass to 30% by mass. Is more preferred. It is also possible for the binder polymer having poly (alkyleneoxy) side chains to be present in the form of discrete particles.

The other binder preferably has a structural unit derived from one or more of (meth) acrylic acid, (meth) acrylate, styrene and a styrene derivative, and poly (alkylene glycol) (meth) acrylate. Further, it is more preferable that the other binder contains a structural unit derived from two or more kinds of such monomers.

-Other components-
(1) Surfactant In the above-mentioned image recording layer, a surfactant can be used in order to promote developability and to improve a coated surface state.
Examples of the surfactant include a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a fluorine-based surfactant.

Preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such a fluorine-based surfactant include an anionic type such as a perfluoroalkyl carboxylate, a perfluoroalkyl sulfonate and a perfluoroalkyl phosphate; an amphoteric type such as a perfluoroalkyl betaine; Cationic type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as oligomers containing a group, a hydrophilic group and a lipophilic group, and urethanes containing a perfluoroalkyl group and a lipophilic group. Further, fluorine surfactants described in JP-A Nos. 62-170950, 62-226143 and 60-168144 are also preferably exemplified.

The surfactants can be used alone or in combination of two or more.
The content of the surfactant is preferably from 0.001% by mass to 10% by mass, more preferably from 0.01% by mass to 5% by mass, based on the total mass of the image recording layer.

(2) Colorant For the image recording layer, a pigment or a dye (colored dye) having a large absorption in the visible light region can be used as a colorant for an image. When a colorant is used, it is easy to distinguish between an image area after image formation and a non-image area, and thus it is preferable to add the colorant.
Examples of the pigment used in the present disclosure include phthalocyanine pigments, azo pigments, carbon black, and titanium oxide. In the present disclosure, it is particularly preferable to use a copper phthalocyanine pigment from the viewpoint of image forming sensitivity and printing durability. In particular, in the present disclosure, the image recording layer is infrared-sensitive, and at least one compound selected from the group consisting of triphenylalkyl borate salt compound and tetraphenylborate salt compound, and a copper phthalocyanine pigment. Is preferable. In this case, sensitivity and printing durability are improved.
On the other hand, as for the dye, the case where the image recording layer contains a triphenylalkyl borate salt compound or a tetraphenyl borate salt compound (including a case where the dye is present as a counter ion of an infrared absorbing dye (IR dye) or a photopolymerization initiator). Although the reason is not clear, the lithographic printing plate precursor may be easily fogged by weak light, and the handleability at the time of plate making may be extremely poor, but the above-mentioned borate salt compound is not contained in the image recording layer. In such a case, it can be usefully used as a colorant similarly to the above pigment. Further, since the dye in the present disclosure has higher water solubility than the pigment, the removability (developability) of the non-image portion is significantly improved by using the dye in the image recording layer.
Specific examples of the dye include Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI45170B), Malachite Green (CI42000), Methylene Blue (CI52015), etc., and JP-A-62-293247. Dyes.
Although various colors can be used, red dyes and blue dyes are preferable from the viewpoint of visibility. Oil pink # 312, Victoria Pure Blue, crystal violet (CI42555), methyl violet (CI42535), ethyl violet, rhodamine B (CI45170B), methylene blue (CI52015) and the like.
Preferred are blue dyes such as Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, and Methylene Blue (CI52015).
More preferably, it is Victoria Pure Blue.
The dye is preferably a dye having a maximum absorption wavelength in the visible region (360 nm to 830 nm) of 600 nm to 700 nm, and more preferably a blue dye having a maximum absorption wavelength in the visible region of 600 nm to 700 nm. .
The colorant may contain one kind alone or two or more kinds.
The amount of the colorant added is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 5% by mass, and more preferably 0.05% by mass to 5% by mass, based on the total mass of the image recording layer. More preferably, the content is from 2.5% by mass to 2.5% by mass.

(3) Printing-out agent To the above-mentioned image recording layer, a compound capable of discoloring by an acid or a radical can be added in order to form a printing-out image.
As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

A suitable amount of the dye that changes its color by acid or radical is preferably 0.01% by mass to 10% by mass based on the total mass of the image recording layer.

(4) Polymerization inhibitor A small amount of a thermal polymerization inhibitor is preferably added to the image recording layer in order to prevent unnecessary thermal polymerization of the polymerizable compound during the production or storage of the image recording layer. .
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4′-thiobis (3-methyl-6-t- Butylphenol), 2,2′-methylenebis (4-methyl-6-t-butylphenol), and N-nitroso-N-phenylhydroxylamine aluminum salt.
The addition amount of the polymerization inhibitor is preferably 0.01% by mass to 5% by mass based on the total mass of the image recording layer.

(5) Higher fatty acid derivative, etc. In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to the image recording layer, and the image is formed in the process of drying after coating. It may be unevenly distributed on the surface of the recording layer.
The added amount of the higher fatty acid derivative is preferably 0.1% by mass to 10% by mass based on the total mass of the image recording layer.

(6) Plasticizer The image recording layer may contain a plasticizer in order to improve developability.
Examples of the plasticizer include phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, and diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, and triethylene glycol dicaprylate; phosphate esters such as tricresyl phosphate and triphenyl phosphate ; Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioc Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in.
The content of the plasticizer is preferably 0.1% by mass to 30% by mass based on the total mass of the image recording layer.

(7) Inorganic particles The image recording layer may contain inorganic particles for improving the strength of the cured film and the developability.
Preferred examples of the inorganic particles include silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, and mixtures thereof. These can be used for strengthening a film, strengthening interfacial adhesion by surface roughening, and the like.
The average particle diameter of the inorganic particles is preferably from 5 nm to 10 μm, more preferably from 0.5 μm to 3 μm. When the content is within the above range, the non-image portion which is stably dispersed in the image recording layer, sufficiently retains the film strength of the image recording layer, and is less likely to be stained during printing and has excellent hydrophilicity can be formed.
The inorganic particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic particles is preferably from 0.01% by mass to 40% by mass, more preferably from 0.1% by mass to 30% by mass, based on the total mass of the image recording layer.

(8) Low-molecular hydrophilic compound The above-mentioned image recording layer may contain a low-molecular hydrophilic compound since the developability is improved without lowering the printing durability.
Examples of the low-molecular hydrophilic compound include, for example, water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, glycols such as tripropylene glycol and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, alkylsulfonic acids, toluenesulfonic acids, organic sulfonic acids such as benzenesulfonic acid and salts thereof, and alkylsulfamic acids and the like. Organic sulfamic acids and salts thereof, organic sulfuric acids and salts thereof such as alkyl sulfuric acid and alkyl ether sulfuric acid, organic phosphonic acids and salts thereof such as phenylphosphonic acid, tartaric acid, and oxalic acid , Citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids and the like.
Of these, organic sulfonic acids, organic sulfamic acids, and organic sulfates such as sodium salts and lithium salts of organic sulfuric acids are preferably used.

These compounds have a small structure of the hydrophobic portion and have almost no surface activity, and are clearly distinguished from the aforementioned surfactants in which long-chain alkyl sulfonates and long-chain alkylbenzene sulfonates are used favorably. .

The amount of the low molecular weight hydrophilic compound added to the image recording layer is preferably 0.5% by mass to 20% by mass, and more preferably 1% by mass to 10% by mass, based on the total mass of the image recording layer. More preferably, it is more preferably from 2% by mass to 8% by mass. Within the above range, good developability and printing durability can be obtained.
The low-molecular hydrophilic compounds may be used alone or in a combination of two or more.

(9) Oil Sensitizing Agent In the lithographic printing plate precursor, a phosphonium compound as an oil sensitizing agent can be added to at least one of the image recording layer and the protective layer in order to improve the inking property.
Suitable phosphonium compounds include the compounds described in JP-A-2006-297907 and JP-A-2007-50660.

脂 As the sensitizer, a nitrogen-containing compound is preferable in addition to the phosphonium compound. Preferred nitrogen-containing compounds may be amine salts, quaternary ammonium salts, or structures of imidazolinium salts, benzimidazolinium salts, pyridinium salts, and quinolinium salts. Among these, quaternary ammonium salts and pyridinium salts are preferably used.

The amount of the sensitizer added to the image recording layer or the protective layer is preferably 0.01% by mass to 20% by mass, more preferably 0.05% by mass to 10% by mass, based on the total mass of each layer. , 0.1 to 5% by mass. When the content is in the above range, good ink depositability can be obtained.

(10) Co-sensitizer A known compound such as a chain transfer agent or a co-sensitizer having an action of further improving sensitivity or suppressing polymerization inhibition by oxygen is added to the image recording layer. You may.
Examples of such compounds include amines, e.g. R. Sander et al., "Journal of Polymer Society", vol. 10, p. 3173 (1972), JP-B-44-20189, JP-A-51-82102, JP-A-52-134692, and JP-A-59-138205. JP-A-60-84305, JP-A-62-18537, JP-A-64-33104, and Research Disclosure 33825. Specific examples thereof include triethanolamine, N-N-phenylglycine, N-phenylaspartic acid, and N, N-dialkylaniline derivatives such as ethyl p-dimethylaminobenzoate, p-formyldimethylaniline and p-methylthiodimethylaniline.

Another example of the compound acting as a chain transfer agent is, for example, a group of compounds having SH, PH, SiH, and GeH in the molecule. These can generate a radical by donating hydrogen to a low-activity radical species, or can generate a radical by being oxidized and then deprotonated.

In the image recording layer, a thiol compound (for example, 2-mercaptobenzimidazoles, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 3-mercaptotriazoles, 5-mercaptotetrazole, etc.) is particularly chained. It can be preferably used as a transfer agent. Among them, thiol compounds described in JP-A-2006-091479 are particularly preferably used. By using this thiol compound as a chain transfer agent, the problem of odor and the decrease in sensitivity due to evaporation from the image recording layer or diffusion to other layers are avoided, excellent storage stability, and furthermore, high sensitivity and high resistance A lithographic printing plate precursor of the printing is obtained.

The use amount of these sensitizers or chain transfer agents is preferably 0.01% by mass to 20% by mass, and more preferably 0.1% by mass to 15% by mass based on the total mass of the image recording layer. Is more preferable, and the content is more preferably 1.0% by mass to 10% by mass.

-Formation of image recording layer-
The image recording layer is preferably formed by dispersing or dissolving each of the necessary components in a solvent to prepare a coating solution, coating the solution on a support, and drying.
Examples of the solvent used herein include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyllactone, toluene, water and the like. However, the present invention is not limited to this.
The solvent can be used alone or in combination of two or more.
The solid content concentration of the coating solution is preferably 1% by mass to 50% by mass.

The image recording layer may be prepared by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and applying the coating multiple times and drying to form an image recording layer having a multilayer structure. It is possible.

The coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the application, but is preferably from 0.3 g / m ² to 3.0 g / m ² . Within the above range, good sensitivity and good film characteristics of the image recording layer can be obtained.
As a coating method, a method described later can be used.

(Protective layer)
The lithographic printing plate precursor is preferably provided with a protective layer (oxygen blocking layer) on the image recording layer in order to block diffusion and intrusion of oxygen which hinders the polymerization reaction at the time of exposure. As a material that can be used for the protective layer, any of a water-soluble polymer and a water-insoluble polymer can be appropriately selected and used, and if necessary, a mixture of two or more can be used. Specifically, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyvinylpyrrolidone, a water-soluble cellulose derivative, poly (meth) acrylonitrile and the like can be mentioned. Among these, it is preferable to use a water-soluble polymer compound having relatively excellent crystallinity. Specifically, it is preferable to use polyvinyl alcohol as a main component in terms of basic properties such as oxygen barrier properties and development removal properties. Gives the best results.

(4) The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, or an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, a part may have another copolymer component. Polyvinyl alcohol is obtained by hydrolyzing polyvinyl acetate. Specific examples of polyvinyl alcohol include those having 69.0 mol% to 100 mol% and having a polymerization repeating unit in the range of 300 to 2,400. Can be mentioned. Specifically, PVA-102, PVA-103, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS manufactured by Kuraray Co., Ltd. , PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-235, PVA-217EE, PVA-217E, PVA -220E, PVA-224E, PVA-403, PVA-405, PVA-420, PVA-424H, PVA-505, PVA-617, PVA-613, PVA-706, L-8 and the like. Alternatively, they can be used in combination. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is from 20% by mass to 95% by mass, more preferably from 30% by mass to 90% by mass.

公知 Also, known modified polyvinyl alcohol can be preferably used. Particularly, acid-modified polyvinyl alcohol having a carboxylic acid group or a sulfonic acid group is preferably used. Specifically, polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137 are preferably mentioned.

When using a mixture of polyvinyl alcohol and another material, as the components to be mixed, modified polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoint of oxygen barrier properties, development removability, and the content in the protective layer is preferably Preferably it is 3.5% by mass to 80% by mass, more preferably 10% by mass to 60% by mass, still more preferably 15% by mass to 30% by mass.

As another composition of the protective layer, glycerin, dipropylene glycol or the like can be added to the (co) polymer in an amount equivalent to several mass% to impart flexibility. Anionic surfactants such as sodium silicate; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; and nonionic surfactants such as polyoxyethylene alkylphenyl ether are added to the (co) polymer in a number. % By mass.

Further, the protective layer in the lithographic printing plate precursor preferably contains an inorganic layer compound for the purpose of improving oxygen barrier properties and image recording layer surface protective properties. Among the inorganic layered compounds, fluorine-based swellable synthetic mica, which is a synthetic inorganic layered compound, is particularly useful. Specifically, an inorganic layered compound described in JP-A-2005-119273 is preferably exemplified.

The coating amount of the protective layer, the coating amount after drying is preferably in the range of ^{^{0.02g / m 2 ~ 10g / m}} 2, when the protective layer contains the inorganic stratiform compound, 0.1 g / m more preferably in the range of ^² ~ 5g / ^m ^2, in case of not containing an inorganic stratiform compound, it is more preferably in the range of ^{^{0.5g / m 2 ~ 5g / m}} 2.

(Support)
As the support used for the lithographic printing plate precursor according to the present disclosure, a known support is used.
The support used in the lithographic printing plate precursor according to the present disclosure is preferably an aluminum support, and more preferably a hydrophilized aluminum support.
Among them, an anodized aluminum plate is more preferable, and a roughened and anodized aluminum plate is particularly preferable.
The surface roughening treatment and the anodic oxidation treatment can be performed by known methods.
If necessary, the aluminum plate may be subjected to a process of enlarging or sealing micropores of an anodized film described in JP-A-2001-253181 or JP-A-2001-322365, and US Pat. Nos. 3,714,066, 3,181,461, 3,280,734, and 3,902,734, and alkali metal silicates described in U.S. Pat. 276,868, 4,153,461, and 4,689,272 by appropriately selecting a surface hydrophilization treatment with polyvinylphosphonic acid or the like. Can be.
The support preferably has a center line average roughness Ra of 0.10 μm to 1.2 μm.
The color density of the support is preferably 0.15 to 0.65 as a reflection density value. Within this range, good image forming properties due to the prevention of halation during image exposure and good plate inspection properties after development can be obtained.
The thickness of the support is preferably from 0.1 mm to 0.6 mm, more preferably from 0.15 mm to 0.4 mm, and even more preferably from 0.2 mm to 0.3 mm.

If necessary, a back coat layer containing an organic polymer compound described in JP-A-5-45885 and a silicon alkoxy compound described in JP-A-6-35174 is formed on the back surface of the support. Can be provided.

(Support hydrophilic treatment, undercoat layer)
In the lithographic printing plate precursor, in order to improve the hydrophilicity of the non-image area and prevent printing stains, the surface of the support is subjected to a hydrophilic treatment, or an undercoat layer is provided between the support and the image recording layer. It is also preferable to provide.

Examples of the treatment for hydrophilizing the surface of the support include an alkali metal silicate treatment in which the support is immersed in an aqueous solution such as sodium silicate or an electrolytic treatment, a method of treating with potassium fluorozirconate, and a method of treating with polyvinyl phosphonic acid. However, a method of immersion treatment in an aqueous solution of polyvinyl phosphonic acid is preferably used.

As the undercoat layer, an undercoat layer having a compound having an acid group such as phosphonic acid, phosphoric acid, or sulfonic acid is preferably used. It is preferable that these compounds further contain a polymerizable group in order to improve the adhesion to the image recording layer. As the polymerizable group, an ethylenically unsaturated bond group is preferable. Further, a compound having a hydrophilicity-imparting group such as an ethyleneoxy group can also be mentioned as a suitable compound.
These compounds may be low molecular or high molecular polymers. These compounds may be used as a mixture of two or more kinds, if necessary.
A silane coupling agent having an addition-polymerizable ethylenically unsaturated bond group described in JP-A-10-282679 and an silane coupling agent having an ethylenically unsaturated bond group described in JP-A-2-304441. And the like. JP-A-2005-238816, JP-A-2005-125749, JP-A-2006-239867, and JP-A-2006-215263, crosslinkable groups (preferably ethylenically unsaturated bonding groups), and a support Those containing a low molecular weight or high molecular weight compound having a functional group interacting with the surface and a hydrophilic group are also preferably used.

The undercoat layer is applied by a known method. The coating amount (solid content) of the undercoat layer is preferably from 0.1 mg / m ² to 100 mg / m ² , more preferably from 1 mg / m ² to 30 mg / m ² .

A lithographic printing plate precursor can be produced by applying a coating solution for each constituent layer according to a usual method, followed by drying to form each constituent layer. For coating, a die coating method, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, a slide coating method, or the like is used.

<Development process>
The method for preparing a lithographic printing plate according to the present disclosure includes a step of performing a developing treatment with a developer having a pH of 10 or more and less than 12 (developing step), wherein the developer is an amphoteric surfactant and a component other than the amphoteric surfactant. And a surfactant.
Further, it is preferable that the method for preparing a lithographic printing plate according to the present disclosure does not include a step of washing the planographic printing plate obtained by the developing treatment with water (rinsing step) after the step of performing the developing treatment. When the developer contains an amphoteric surfactant and a surfactant other than the amphoteric surfactant, these at least two surfactants act in concert, and at least one surfactant is used as a plate surface. By adhering to the lithographic printing plate according to the present disclosure, the method for producing a lithographic printing plate is excellent in developing sludge suppression properties. Few.
The term “water washing step” as used herein refers to a step performed after the developing step in a general developing system. As the washing step, it is generally known to use any water such as general tap water, well water, ion-exchanged water, distilled water, etc. It is also known that fresh water is always used as the water used in the water washing step, or water used in the water washing step is circulated through a filter and reused.

<< Developer >>
The developer used in the method for preparing a lithographic printing plate according to the present disclosure has a pH of 10 or more and less than 12, and contains an amphoteric surfactant and a surfactant other than the amphoteric surfactant.

-Amphoteric surfactant-
The developer contains an amphoteric surfactant.
Examples of the amphoteric surfactant include betaine compounds (carbobetaine compounds), sulfobetaine compounds, amine oxide compounds, and phosphine oxide compounds.
Above all, from the viewpoints of development sludge suppression and scratch resistance, a carbobetaine compound, a sulfobetaine compound, or an amine oxide compound is preferred, a carbobetaine compound or a sulfobetaine compound is more preferred, and a carbobetaine compound is particularly preferred.

Further, the amphoteric surfactant preferably contains a compound represented by the following formula (I) or (II) from the viewpoint of development sludge suppression and scratch resistance, and is represented by the following formula (II). More preferably, the compound contains

In the formula (I), R ¹ to R ³ each independently represent an alkyl group, and at least one of the above R ¹ to R ³ has an ester bond (— (C ＝ O)) in the alkyl chain of the alkyl group. It preferably has a linking group selected from the group consisting of O-), an ether bond (-O-), and an amide bond (-NH- (C = O)-). Preferably, one or two of R ¹ to R ³ have the above-mentioned linking group, and more preferably one has the above-mentioned linking group.
The alkyl group may have a substituent, and the substituent is, for example, a hydroxy group.
The carbon number of each of R ¹ to R ³ is independently preferably 1 to 30, more preferably 1 to 24, further preferably 1 to 20, and particularly preferably 1 to 18. preferable. The total number of carbon atoms of R ¹ to R ^{3 in} the formula (I) is preferably from 8 to 22, and more preferably from 10 to 20. In the case where R ¹ to R ³ have an ester bond or an amide bond as a linking group, the above total number of carbon atoms means the total number of carbon atoms included in the linking group. is there.
Further, at least one of R ¹ to R ³ is preferably an alkyl group having 10 to 30 carbon atoms, an unsubstituted alkyl group having 10 to 30 carbon atoms, and an acyloxyalkyl group having 10 to 30 carbon atoms. More preferably an alkoxyalkyl group having 10 to 30 carbon atoms or an alkylamidoalkyl group having 10 to 30 carbon atoms, and an unsubstituted alkyl group having 10 to 30 carbon atoms or an alkyl group having 10 to 30 carbon atoms. It is more preferably an amidoalkyl group, particularly preferably an alkylamidoalkyl group having 10 to 30 carbon atoms.

In the formula (II), R ⁴ to R ⁶ each independently represent an alkyl group, and at least one of the above R ⁴ to R ⁶ has an ester bond (-(C = O ) It preferably has a linking group selected from the group consisting of O-), an ether bond (-O-), and an amide bond (-NH- (C = O)-). In addition, one or two of the above R ⁴ to R ⁶ preferably have the above-mentioned linking group, and more preferably one has the above-mentioned linking group.
The alkyl group may have a substituent, and the substituent is, for example, a hydroxy group.
The carbon number of R ⁴ to R ⁶ is each independently preferably 1 to 30, more preferably 1 to 24, still more preferably 1 to 20, and particularly preferably 1 to 18. preferable. The total number of carbon atoms of R ⁴ to R ^{6 in} the formula (II) is preferably from 8 to 25, and more preferably from 11 to 21. In the case where R ⁴ to R ⁶ have an ester bond or an amide bond as a linking group, the above total number of carbon atoms means the total number of carbon atoms in the linking group. is there.
Further, at least one of R ⁴ to R ⁶ is preferably an alkyl group having 10 to 30 carbon atoms, an unsubstituted alkyl group having 10 to 30 carbon atoms, and an acyloxyalkyl group having 10 to 30 carbon atoms. More preferably an alkoxyalkyl group having 10 to 30 carbon atoms or an alkylamidoalkyl group having 10 to 30 carbon atoms, and an unsubstituted alkyl group having 10 to 30 carbon atoms or an alkyl group having 10 to 30 carbon atoms. It is more preferably an amidoalkyl group, particularly preferably an alkylamidoalkyl group having 10 to 30 carbon atoms.
In the above formula (II), L represents an alkylene group, and the alkylene group preferably has 1 to 20 carbon atoms, more preferably has 1 to 12 carbon atoms, and has 1 to 6 carbon atoms. More preferably, it has 1 to 4 carbon atoms.
The alkyl group and the alkylene group may have a substituent, and examples of the substituent include a hydroxy group.
In the above formula (II), A represents a carboxylate ion or a sulfonate ion, and is preferably a carboxylate ion.

具体 Specific examples of the compound represented by the above formula (I) or (II) include, but are not limited to, the following structures.

Among these, BO-5 to BO-7, BC-1, BC-2, BC-5, or BC-6 is particularly preferable as the compound represented by the above formula (I) or (II). .
Examples of the compound represented by the above formula (I) or (II) include “Amphitol” series manufactured by Kao Corporation, “Softazoline” series manufactured by Kawaken Fine Chemical Co., Ltd., and “Pionin” manufactured by Takemoto Yushi Co., Ltd. C "series," Sophamine "series," Obazoline "series manufactured by Toho Chemical Industry Co., Ltd., and the like, and commercially available products.

The amphoteric surfactants may be used alone or in combination of two or more.
The content of the amphoteric surfactant is preferably 0.5% by mass to 20% by mass, and more preferably 1% by mass to 15% by mass, based on the total mass of the developing solution, from the viewpoints of development sludge suppression and scratch resistance. Is more preferable, and particularly preferably 4 to 10% by mass.

-Surfactants other than amphoteric surfactant-
The developer contains a surfactant other than the amphoteric surfactant.
Examples of the surfactant other than the amphoteric surfactant include an anionic surfactant, a nonionic surfactant, and a cationic surfactant.
Among them, at least one surfactant selected from the group consisting of anionic surfactants and nonionic surfactants is preferred from the viewpoints of development sludge suppression and scratch resistance.

アニオン The anionic surfactant that can be used in the present disclosure is not particularly limited, and a conventionally known anionic surfactant can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy polyoxyethylene Propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyltaurine sodium salts, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates, sulfated castor oil, sulfated tallow oil, Fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxy Tylene alkyl phenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene-maleic anhydride copolymer And partially saponified olefin-maleic anhydride copolymers, naphthalene sulfonate formalin condensates, aromatic sulfonates, aromatic substituted polyoxyethylene sulfonates, and the like. Among these, dialkyl sulfosuccinates, alkyl sulfate salts and / or alkyl naphthalene sulfonates are particularly preferably used.

The anionic surfactant is preferably a compound having an aromatic ring structure from the viewpoint of development sludge suppression and scratch resistance, and an aromatic ring structure, a sulfonate structure, a carboxylate structure, and a phosphate. A compound having at least one structure selected from the group consisting of structures is more preferable, and a compound having an aromatic ring structure and a sulfonate structure is particularly preferable.
The aromatic ring structure is preferably a benzene ring structure or a naphthalene ring structure, more preferably a naphthalene ring structure, from the viewpoint of development sludge suppression and scratch resistance.

In addition, the anionic surfactant is preferably a compound represented by the following formula (III) or formula (IV).

In formula (III), one of R ^An1 to R ^An5 is preferably an alkyl group, and the other is preferably a hydrogen atom, and one of R ^An1 to R ^An5 is an alkyl group having 1 to 30 carbon atoms. And the other is more preferably a hydrogen atom, and one of R ^An1 to R ^An5 is more preferably an alkyl group having 8 to 20 carbon atoms, and the other is more preferably a hydrogen atom.
In formula (IV), one of R ^An6 to R ^An10 is preferably an alkyl group, and the other is preferably a hydrogen atom. One of R ^An6 to R ^An10 is an alkyl group having 1 to 30 carbon atoms. , And the other is more preferably a hydrogen atom, and even more preferably, one of R ^An6 to R ^An10 is an alkyl group having 8 to 20 carbon atoms, and the other is a hydrogen atom.
Further, R ^An8 in the formula (IV) is preferably an alkyl group.
The alkyl group in R ^An1 to R ^An10 may be linear or branched.
In formula (III) and each X ^{An 1} and X ^An2 independently in Formula (IV), sulfonate, or is preferably a carboxylate group, and more preferably sulfonate.
Also, the sulfonate group in the above X ^{An 1} and X ^An2, carboxylate or phosphate base is an alkali metal salt of sulfonic acid is preferably an alkali metal base of an alkali metal base or phosphoric acid of the carboxylic acid, sulfonic acid More preferably, it is a sodium base, a carboxylic acid sodium base or a phosphoric acid sodium base.
The total number of carbon atoms of R ^An1 to R ^An5 in the formula (III) is preferably 3 to 30, more preferably 8 to 30, and particularly preferably 8 to 20.
The total number of carbon atoms of R ^An6 to R ^An10 in the formula (IV) is preferably 3 to 30, more preferably 8 to 30, and particularly preferably 8 to 20.

Nonionic surfactants that can be used in the present disclosure include, for example, polyethylene glycol-type higher alcohol ethylene oxide adducts, ethylene oxide adducts such as phenol and naphthol, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene Oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, ethylene oxide adduct of oils and fats, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide ) Fatty acid esters of polyhydric alcohol type glycerol and fatty acid esters of pentaerythritol Fatty acid esters of sorbitol and sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines. In addition, surfactants such as acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicone-based surfactants can also be used.

The nonionic surfactant is preferably a compound having an aromatic ring structure from the viewpoint of development sludge suppression and scratch resistance, and more preferably a compound having an aromatic ring structure and an alkyleneoxy chain structure. And a compound having an aromatic ring structure and an alkyleneoxy chain structure having 2 or 3 carbon atoms.
The aromatic ring structure is preferably a benzene ring structure or a naphthalene ring structure, more preferably a naphthalene ring structure, from the viewpoint of development sludge suppression and scratch resistance.

In addition, the nonionic surfactant is preferably a compound represented by the following formula (V).
X ^No -Y ^No -O- (A ^No ) p- (B ^No ) qH (V)
In the formula (V), X ^No represents an aromatic group, Y ^No represents a single bond or an alkylene group having 1 to 10 carbon atoms, A ^No and B ^No are different groups, and —CH ₂ CH ₂ Represents O— or —CH ₂ CH (CH ₃ ) O—, p and q each independently represents an integer of 0 to 100, and the sum of p and q is 2 or more.

X ^No in the formula (V) is preferably a phenyl group, a naphthyl group, or a tristyrylphenyl group, and more preferably a naphthyl group or a tristyrylphenyl group.
As Y ^No in the formula (V), a single bond or an alkylene group having 1 to 3 carbon atoms is preferable, and a single bond is more preferable.
The sum of p and q is preferably 2 to 50, more preferably 10 to 30.
Further, the compound represented by the formula (V) preferably has a — (CH ₂ CH ₂ O) _r — structure. r represents an integer of 2 to 100, preferably 2 to 50, and more preferably 10 to 30.

カチオン The cationic surfactant that can be used in the present disclosure is not particularly limited, and a conventionally known cationic surfactant can be used. Examples include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylenepolyamine derivatives.

Surfactants other than amphoteric surfactants can be used alone or in combination of two or more.
The content of the surfactant other than the amphoteric surfactant is preferably from 0.01% by mass to 10% by mass, and more preferably from 0.01% by mass, based on the total mass of the developer, from the viewpoints of the development sludge suppressing property and the scratch resistance. -5% by mass is more preferred.
Further, the content of the amphoteric surfactant in the developer is preferably larger than the content of the surfactant other than the amphoteric surfactant in the developer from the viewpoints of the development sludge suppressing property and the scratch resistance.
Further, the value of (the content of the amphoteric surfactant in the developer) / (the content of the surfactant other than the amphoteric surfactant in the developer) is 0 from the viewpoint of the development sludge suppressing property and the scratch resistance. It is preferably from 0.8 to 10, more preferably from 1.0 to 7, further preferably from 1.1 to 5, and particularly preferably from 2.0 to 4.0.

-water-
The developer preferably contains water.
Here, water refers to pure water, distilled water, ion-exchanged water, tap water, and the like, and water of any hardness can be used.
The water content in the developer is preferably 50% by mass or more. Moreover, it is preferable that it is 99.5 mass% or less, and it is more preferable that it is 99 mass% or less.

-Organic solvent-
The developer preferably contains an organic solvent from the viewpoints of developability and suppression of development sludge.
The organic solvent is preferably an organic compound in a liquid state at normal temperature (20 ° C.).
The organic solvent is preferably a compound that solubilizes the development removal component. The organic solvent is preferably dissolved at 20 ° C. in water which is a main component of the developer.
The development-removed component is solubilized by forming micelles with a surfactant (amphoteric surfactant and a surfactant other than the amphoteric surfactant) in the developer, or is dissolved by an organic solvent. . It is more advantageous to include an organic solvent from the viewpoint of the development speed and the stability of the development-removed components in the developer, but the single-bath treatment is disadvantageous in terms of printing stains. This is thought to be because if the organic solvent of the developer adhering to the non-image area after development volatilizes, the development-removed components dissolved by the organic solvent precipitate and adhere to the non-image area surface. I have. Therefore, if there is no problem in developability, it is preferable that the content of the organic solvent is small. The content of the organic solvent is preferably less than 5% by mass, more preferably 4% by mass or less, still more preferably 3% by mass or less, and particularly preferably 0.1% by mass or less. preferable.

The organic solvent preferably has a solubility in water at 20 ° C. of 1.5 g / 100 ml to 7.0 g / 100 ml. More preferably, it is 2.5 g / 100 ml to 5.0 g / 100 ml.
Specific examples of the organic solvent usable in the present disclosure include 1-pentanol (2.7 g / 100 ml), 2-pentanol (4.5 g / 100 ml), 3-pentanol (5.2 g / 100 ml), 2-methyl-1-butanol (3.0 g / 100 ml), 3-methyl-1-butanol (2.7 g / 100 ml), 3-methyl-2-butanol (5.6 g / 100 ml), neopentyl alcohol (3 0.5 g / 100 ml), 4-methyl-2-pentanol (2.0 g / 100 ml), benzyl alcohol (4.0 g / 100 ml), ethylene glycol monophenyl ether (2.7 g / 100 ml), propylene glycol mono n- Butyl ether (4.4 g / 100 ml), propyl acetate (1.6 g / 100 ml), isopropyl acetate (4.3 / 100 ml), diethylene glycol monobutyl ether acetate (6.5 g / 100 ml), diethyl ketone (1.7 g / 100 ml), 2-pentanone (4.0 g / 100 ml), methyl isobutyl ketone (1.9 g / 100 ml) and the like. Can be These may be used alone or in combination of two or more.
Among these, benzyl alcohol is preferred.

(4) The pH of the developer is 10 or more and less than 12, and is preferably from 10.2 to 11.8, more preferably from 10.5 to 11.5, from the viewpoint of suppressing development sludge.

The developer may additionally contain an alkali agent for the purpose of adjusting pH and assisting dissolution of the non-image area image recording layer. Examples of the alkali agent include a metal hydroxide, a carbonate or a bicarbonate, and an organic alkali agent.
The metal hydroxide is preferably an alkali metal hydroxide, more preferably lithium hydroxide, sodium hydroxide, or potassium hydroxide.
The carbonate and bicarbonate are not particularly limited, but are preferably alkali metal salts. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable.
Examples of the organic alkaline agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, and monoisopropanol. Examples thereof include amine compounds such as amine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine; and tetramethylammonium hydroxide.
Among them, a metal hydroxide or an organic alkali agent is preferable, an organic alkali agent is more preferable, and an amine compound is particularly preferable.
These alkaline agents are used alone or in combination of two or more.

(4) Other components in the developer will be described below.

The developer preferably contains a water-soluble polymer compound for the purpose of, for example, protecting the surface of the non-image area after the development of the image recording layer is removed.
Examples of the water-soluble polymer compound that can be used in the present disclosure include soybean polysaccharide, starch, gum arabic, dextrin, cellulose derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol and Derivatives, polyvinylpyrrolidone, polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, and the like.
The preferred acid value of the water-soluble polymer compound is from 0 meq / g to 3.0 meq / g.
The acid value can be measured by titration with a 0.1 mol / L aqueous sodium hydroxide solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) using a general automatic titrator.

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

Examples of the starch include potato starch, potato starch, tapioca starch, wheat starch, corn starch, and the like, and further modified starches and starch derivatives thereof.
The modified starch can be produced by a method in which the number of glucose residues per molecule is decomposed in the range of 5 to 30 with an acid or an enzyme, and oxypropylene is further added in an alkali.
As the starch derivative, roasted starch such as British gum, enzyme-modified dextrin such as enzyme dextrin and Shardinger dextrin, oxidized starch shown in solubilized starch, pregelatinized starch such as denatured pregelatinized starch and non-denatured pregelatinized starch, Esterified starch such as phosphate starch, fat starch, sulfate starch, nitrate starch, xanthate starch and carbamic acid starch, carboxyalkyl starch, hydroxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch, carbamylethyl Starch, etherified starch such as dialkylamino starch, crosslinked starch such as methylol crosslinked starch, hydroxyalkyl crosslinked starch, phosphoric acid crosslinked starch, dicarboxylic acid crosslinked starch, etc., starch polyacrylamide copolymer, starch polyacrylic acid copolymer, starch Polyacetic acid Nyl copolymer, starch polyacrylonitrile copolymer, chaotic starch polyacrylate copolymer, chaotic starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer, starch polypropylene copolymer Starch graft polymers such as polymers are preferred.

Among the water-soluble polymer compounds, soybean polysaccharide, starch, gum arabic, dextrin, carboxymethylcellulose or polyvinyl alcohol is preferred, and gum arabic or starch is more preferred.
Two or more water-soluble polymer compounds can be used in combination.
The content of the water-soluble polymer compound in the developer is preferably 0.1% by mass to 20% by mass, more preferably 0.5% by mass to 10% by mass.

In addition to the above, the developer may contain a wetting agent, a preservative, a chelating compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like.

As the 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.
One wetting agent may be used alone, or two or more may be used in combination.
The wetting agent is preferably used in an amount of 0.1% by mass to 5% by mass based on the total mass of the developer.

Preservatives include phenol or its derivatives, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzoisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, benzotriazole derivatives , Amidating anidine derivatives, quaternary ammonium salts, derivatives such as pyridine, quinoline, guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3-diol, 1,1-Dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used. One preservative may be used alone, but it is preferable to use two or more preservatives in combination so as to be effective against various molds and sterilization.
The content of the preservative is an amount stably exerting an effect on bacteria, mold, yeast and the like, and varies depending on the kind of bacteria, mold and yeast. The range is preferably from 0.01% to 4% by mass.

Examples of the chelate compound include ethylenediaminetetraacetic acid, its potassium salt and its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt and its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, and hydroxyethylethylenediaminetriacetic acid , Potassium salt, sodium salt thereof; nitrilotriacetic acid, sodium salt thereof; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt thereof; aminotri (methylenephosphonic acid), potassium salt, sodium salt thereof And organic phosphonic acids or phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the above chelating agents.
The chelating agent is preferably selected from those which are stably present in the developer and do not impair printability.
The content of the chelating agent is preferably 0.001% by mass to 1.0% by mass based on the total mass of the developer.

As the defoaming agent, compounds of general silicone type self-emulsification type, emulsification type, nonionic type HLB (Hydrophile-Lipophile Balance) of 5 or less can be used. Silicone defoamers are preferred. Among them, any of emulsification dispersion type and solubilization can be used.
The content of the antifoaming agent is preferably in the range of 0.001% by mass to 1.0% by mass based on 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, and organic phosphonic acid. . Organic acids can also be used in the form of their alkali metal or ammonium salts.
The content of the organic acid is preferably 0.01% by mass to 0.5% by mass based on the total mass of the developer.

As the inorganic acid and the inorganic salt, phosphoric acid, metaphosphoric acid, ammonium phosphate monobasic, ammonium phosphate dibasic, sodium phosphate monobasic, sodium phosphate dibasic, potassium phosphate monobasic, potassium phosphate dibasic, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate, and the like.
The content of the inorganic acid and the inorganic salt is preferably 0.01% by mass to 0.5% by mass based on the total mass of the developer.

現像 The developing process in the developing step is not particularly limited and may be performed by a known method, but is preferably performed using an automatic processor equipped with a rubbing member. Further, the development processing can be suitably performed by an automatic processor equipped with a supply means for the developer or the like. Examples of the automatic processor include an automatic processor described in Japanese Patent Application Laid-Open No. 2006-235227, which performs a rubbing process while transporting a lithographic printing plate precursor after image recording. Among them, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

The rotating brush roll that can be preferably used in the present disclosure can be appropriately selected in consideration of the difficulty of damaging the image area, the stiffness of the lithographic printing plate precursor support, and the like.
As the rotating brush roll, a known one formed by implanting a brush material in a plastic or metal roll can be used. For example, as described in JP-A-58-159533 and JP-A-3-100554, and as described in Japanese Utility Model Publication No. 62-167253, metal or plastic in which a brush material is implanted in a row is used. A brush roll obtained by radially wrapping the grooved material radially around a plastic or metal roll serving as a core can be used.
Examples of the brush material include plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, and polyacrylics such as polyacrylonitrile and polyalkyl (meth) acrylate). , And polyolefin-based synthetic fibers such as polypropylene and polystyrene). For example, fibers having a hair diameter of 20 μm to 400 μm and a hair length of 5 mm to 30 mm can be suitably used. .
The outer diameter of the rotating brush roll is preferably 30 mm to 200 mm, and the peripheral speed of the tip of the brush rubbing the plate surface is preferably 0.1 m / sec to 5 m / sec.

The rotating direction of the rotating brush roll may be the same direction or the opposite direction to the conveying direction of the planographic printing plate precursor, but as shown in FIG. 2, two or more rotating brush rolls are used. In this case, it is preferable that at least one rotating brush roll rotates in the same direction and at least one rotating brush roll rotates in the opposite direction. Thereby, the removal of the image recording layer in the unexposed portion is further ensured. Further, it is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

現像 The developer used in the present disclosure may always use a fresh solution, but it is preferable that the developer after the development processing is circulated through a filter and used repeatedly.

As the filter used for filtering the developer used in the developing step, any filter can be used as long as foreign matter mixed in the developer can be filtered. As the material of the filter, polyester resin, polypropylene resin, polyethylene resin, cellulose resin, cotton and the like are preferably used. In addition, it is preferable that the filter is housed in a housing in the form of a cartridge as a replaceable filter. The cartridge is, for example, a pleated type formed by subjecting a filter paper made of cellulose fiber to an epoxy resin processing for reinforcement of strength and prevention of fiber detachment, and pleating in order to increase a filtration area, a yarn composed of many fibers (fiber of fiber). Bundle) is wound up to obtain a gentler density gradient than the central cylinder, or the adsorbent is stored in a plastic case made of polyethylene or the like, or mainly composed of resin, cellulose, glass fiber and water-absorbing polymer It is preferable to use an adsorption type in which an adsorbent such as activated carbon is supported on the media. The adsorbent was selected from silica gel, activated carbon, activated aluminum, molecular sieves, clay and superabsorbent fibers, calcium carbonate, calcium sulfate, potassium permanganate, sodium carbonate, potassium carbonate, sodium phosphate and active metals Materials and ion exchangers used for various filters can be used.
As an available filter, a cartridge filter “TCW type”, “TCP type”, “TCS type” or the like manufactured by Advantech Toyo Co., Ltd. is preferably used.
The mesh diameter of the filter is preferably 5 μm to 500 μm, more preferably 10 μm to 200 μm, and still more preferably 20 μm to 100 μm.

In the present disclosure, it is arbitrarily possible to provide a drying step after the developing step. It is particularly preferable to provide it in the last step of the automatic processor.
The drying step is preferably performed by removing most of the developer with a roller nip and then blowing dry air at an arbitrary temperature.

Hereinafter, the present disclosure will be described in detail with reference to Examples, but the present disclosure is not limited thereto. In this example, “%” and “parts” mean “% by mass” and “parts by mass”, respectively, unless otherwise specified. The numbers at the lower right of the structural units of the compounds represent molar ratios unless otherwise specified.

(Examples 1 to 10 and Comparative Examples 1 to 7)
<Preparation of aluminum support 1>
To remove rolling oil on the surface of an aluminum plate (material: JIS A 1050) having a thickness of 0.3 mm, a 10% by mass aqueous sodium aluminate solution was subjected to a degreasing treatment at 50 ° C. for 30 seconds. The aluminum surface was grained using ^three 3 mm bundled nylon brushes and a Pumice-water suspension having a median diameter of 25 μm (specific gravity: 1.1 g / cm ³ ), and thoroughly washed with water. This plate was immersed in a 25% by mass aqueous solution of sodium hydroxide at 45 ° C. for 9 seconds to perform etching, washed with water, further immersed in a 20% by mass aqueous solution of nitric acid at 60 ° C. for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .
Next, an electrochemical surface roughening treatment was continuously performed using an AC voltage of 60 Hz. At this time, the electrolytic solution was a 1% by mass aqueous solution of nitric acid (containing 0.5% by mass of aluminum ion), and the solution temperature was 50 ° C. The AC power supply waveform is an electrochemical roughening process using a trapezoidal rectangular wave alternating current with a time TP from a current value reaching zero to a peak to a peak value of 0.8 msec, a duty ratio of 1: 1 and a carbon electrode as a counter electrode. Was done. 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 shunted to the auxiliary anode. The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was an anode. Thereafter, water washing by spraying was performed.
Subsequently, nitric acid electrolysis was performed using a 0.5% by mass aqueous solution of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution at a liquid temperature of 50 ° C. under the conditions of an electric charge of 50 C / dm ² when the aluminum plate was an anode. Electrochemical surface roughening treatment was performed in the same manner as described above, and then water washing was performed by spraying. Next, a 2.5 g / m ² DC anodic oxide film was formed on the plate at a current density of 15 A / dm ^{2 using a} 15% by mass aqueous solution of sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution. And dried.
Further, a water vapor at 100 ° C. was sprayed onto the anodic oxide film at a pressure of 1.033 × 10 ⁵ Pa for 8 seconds to perform a sealing treatment.
Next, the aluminum support obtained by the anodic oxidation treatment was immersed in a treatment liquid at 53 ° C. in which 0.4% by mass of polyvinylphosphonic acid (manufactured by PCAS) was dissolved in pure water for 10 seconds, and excess nip rolls were used. The treatment liquid was completely removed, and an aluminum support 1 was produced.

<Formation of undercoat layer>
Next, the following undercoat layer coating solution (1) was applied onto the aluminum support 1 so that the dry coating amount was 20 mg / m ² , to prepare a support having an undercoat layer.

[Undercoat layer coating liquid (1)]
-Undercoat layer compound (1) having the following structure: 0.18 part-Methanol: 55.24 parts-Water: 6.15 parts

<Formation of Image Recording Layer>
One of the following image recording layer coating solutions 1 to 3 shown in Table 2 was coated on the undercoat layer with a bar, followed by oven drying at 100 ° C. for 60 seconds, and image recording with a dry coating amount of 1.0 g / m ² . A layer was formed.

-Composition of image recording layer coating liquid 1-
The following binder polymer: 0.23 parts by mass Urethane methacrylate oligomer (formed from the reaction of glycerol dimethyl acrylate, glycerol monomethyl acrylate, propylene glycol methacrylate, and hexamethylene diisocyanate): 0.38 parts by mass ethoxylated bisphenol A diacrylate (Shin Nakamura NK Ester BPE500 (manufactured by Chemical Industry Co., Ltd.): 0.06 parts by mass The following polymerization initiator-1: 0.07 parts by mass The following sensitizing dye-1: 0.04 parts by mass Chain transfer agent (mercaptobenzothiazole): 0 0.005 parts by mass Pigment (polymer dispersion of Helogen Blue 7565): 0.038 parts by mass Surfactant (BYK307 manufactured by BYK): 0.002 parts by mass Phenoxyethanol: 10.35 parts by mass Acetone: 1.15 parts by mass Department

数値 The numerical value at the lower right of the parenthesis of each structural unit in the binder polymer represents a mass ratio.

-Composition of image recording layer coating liquid 2-
The image recording layer coating solution 1 was prepared in the same manner as the image recording layer coating solution 1 except that the binder polymer was changed to the following binder polymer.

-Composition of image recording layer coating liquid 3-
The following binder polymer: 4.09 parts by mass SR399 (manufactured by Sartomer Japan KK, dipentaerythritol pentaacrylate): 2.66 parts by mass NK-Ester A-DPH (manufactured by Shin-Nakamura Chemical Co., Ltd., dipentaerythritol) Hexaacrylate): 2.66 parts by mass CD9053 (ester compound of trifunctional organic acid manufactured by Sartomer Japan KK): 0.53 parts by mass bis-t-butylphenyliodonium tetraphenylborate: 0.96 parts by mass Fluor N2900 (Cytonix surfactant): 0.11 parts by mass Pigment 1: 0.73 parts by mass Infrared absorbent: 0.27 parts by mass Phosmer PE (manufactured by Unichemical Co., Ltd.): 0.55 parts by mass Exchanged water: 13.77 parts by mass 1-methoxy-2-propanol : 48.18 parts by mass 2-butyrolactone: 13.77 parts by mass 2-butanone: 61.94 parts by mass

<Formation of protective layer>
As shown in Table 2, a protective layer coating solution 1 having the following composition was coated on the image recording layer with a bar, and then dried in an oven at 120 ° C. for 60 seconds to provide a dry coating amount of 0.15 g / m ² . A layer was formed to obtain each lithographic printing plate precursor.

-Composition of coating solution 1 for protective layer-
PVA-1 (polyvinyl alcohol, Gohselan L-3266, manufactured by Nippon Synthetic Chemical Co., Ltd.): 0.61 parts by mass PVA-2 (polyvinyl alcohol, Nichigo G-polymer AZF8035, manufactured by Nippon Synthetic Chemical Co., Ltd.): 0. 32 parts by mass Surfactant (polyoxyethylene lauryl ether, Emarex 710, manufactured by Nippon Emulsion Co., Ltd.): 0.002 parts by mass Water: 13 parts by mass

<Exposure>
As shown in Table 2, the lithographic printing plate precursor was exposed under the following exposure conditions 1 or 2.

-Exposure condition 1-
The obtained lithographic printing plate precursor was image-exposed using a Violet semiconductor laser plate setter Vx9600 (InGaN-based semiconductor laser (emission wavelength: 405 nm ± 10 nm / output: 30 mW)) manufactured by Fujifilm Electronic Imaging (FFEI). Image drawing was performed at a resolution of 2,438 dpi (dot per inch) using an FM screen (TAFFETA 20) manufactured by FUJIFILM Corporation at a plate surface exposure of 0.05 mJ / cm ² .

-Exposure conditions 2-
The obtained lithographic printing plate precursor was subjected to an external drum rotation speed of 1,000 rpm (each time), a laser output of 70%, and a resolution of 2,400 dpi using a Fujifilm Corporation Luxel PLATESETTER T-6000III equipped with an infrared semiconductor laser. (Dot per inch).

<Development processing>
The lithographic printing plate precursor was developed using the developing solution shown in Table 2 and the following developing conditions 1 or 2 shown in Table 2 to produce each lithographic printing plate.

-Development condition 1-
Using the developing solution shown in Table 2, in an automatic developing machine having the structure shown in FIG. 1, preheating was performed at 100 ° C. for 10 seconds, and the immersion time (developing time) in the developing solution was 20 seconds at a transport speed. A development process was performed to obtain a lithographic printing plate.
The automatic development processor shown in FIG. 1 includes a pre-heating unit 104 that heats the entire surface of a lithographic printing plate precursor (hereinafter, also referred to as a “PS plate”) 100 before development, a developing unit 106 that develops the PS plate 100, A drying unit 110 for drying the PS plate 100 after development is provided. The PS plate 100 subjected to the image exposure is carried into the pre-heating unit 104 by the carry-in roller 112 from the carry-in entrance, and is heated in the heating chamber 105. A skewer roller 114 is provided in the heating chamber 105. The heating chamber 105 is provided with a heating means such as a heating means (not shown) and a hot air supply means. Next, the PS plate 100 is transported to the developing unit 106 by the transport rollers 116. In the developing tank 120 of the developing unit 106, a transport roller 122, a brush roller 124, and a squeeze roller 126 are provided in this order from the upstream side in the transport direction, and a backup roller 128 is provided at an appropriate position therebetween. The PS plate 100 is immersed in the developing solution while being conveyed by the conveying roller 122 and the brush roller 124 is rotated to remove a non-image portion of the PS plate 100 and is subjected to development processing. The developed PS plate 100 is conveyed to the next drying unit 110 by a squeeze roller (unloading roller) 126.
The drying unit 110 is provided with a guide roller 136 and a pair of skewer rollers 138 in order from the upstream side in the transport direction. The drying unit 110 is provided with a drying unit (not shown) such as a hot air supply unit and a heating unit. The drying unit 110 is provided with a discharge port, and the PS plate 100 dried by the drying unit is discharged from the discharge port, and the automatic development processing for the PS plate is completed.

-Developing conditions 2-
The exposed master was developed using the developing solutions shown in Table 2 using an automatic developing apparatus for one-bath processing shown in FIG. 2, and then dried with a dryer.

<Composition of used developers 1 to 15>
Table 1 below shows the compositions of the developing solutions 1 to 15 used in the above development processing.
In addition, each numerical value except the pH column in Table 1 represents the amount of each component, and the unit of the amount of each component is parts by mass.
Further, in Table 1, diethanolamine was added to Table 1 in such an amount as to give a pH.

<Evaluation>
The obtained lithographic printing plate precursor was evaluated by the following method. Table 2 shows the evaluation results.

<Evaluation of processability (evaluation of development sludge suppression)>
After processing 20 m ² of the lithographic printing plate precursor per 1 L of the developing solution shown in Table 2, the developing solution was removed, and the accumulation of developing sludge at the bottom of the processing bath and the filter was observed. Was evaluated according to the following index, and the evaluation was made as a rank of the development sludge suppressing property.
5: Good without deposition.
4: Slight deposition occurs, but no problem.
3: Although some deposition occurs, it can be washed with running water and there is no practical problem.
2: Deposition occurs, but can be cleaned by scrubbing, and is at an acceptable level.
1: Deposition occurs, causing a problem in processability.

<Scratch resistance evaluation>
The obtained lithographic printing plate precursor was alternately laminated with interleaving paper (F interleaving paper manufactured by Daiichi Container Co., Ltd.) to produce a lithographic printing plate precursor laminate. The obtained lithographic printing plate precursor laminate was stacked at a height of 1 m, vibrated for 10 minutes (frequency range: 5 Hz to 55 Hz), exposed and developed under the conditions shown in Table 2, and the non-image The state of occurrence of scratches in the part was visually evaluated. The following criteria were used as evaluation scales.
5: No scratch.
4: There is one scratch that cannot be confirmed with the naked eye, but can be confirmed with a loupe of 6 magnifications.
3: There are some scratches that cannot be confirmed with the naked eye, but can be confirmed with a loupe of 6 magnifications.
2: There are scratches that can be visually confirmed at a plurality of locations.
1: There are scratches over the entire surface.

<Print durability evaluation>
As the number of printed sheets is increased, the image of the image recording layer formed on the lithographic printing plate is gradually worn and ink receptivity is reduced, and accordingly, the ink density of the image on the printing paper is reduced. The obtained lithographic printing plate was subjected to a printing machine (Rithlon, manufactured by Komori Corporation), an ink (Values-G (N) black ink, manufactured by DIC Corporation), a dampening solution (Ecolity-2 (Fujifilm (Fujifilm)). Co., Ltd.) / Tap water = 2/8 (volume ratio)) and printing paper (Toshibishi art paper, continuous weight: 76.5 kg, manufactured by Mitsubishi Paper Mills). The printing durability index was evaluated based on the number of printed sheets when the ink density (reflection density) decreased by 0.1 from the start of printing.

From the results shown in Table 2, all of Examples 1 to 10, which are the methods for producing a lithographic printing plate according to the present disclosure, are superior to the methods for producing a lithographic printing plate according to Comparative Examples 1 to 7 in developing sludge suppression. You can see that.
Further, from the results shown in Table 2, it can be seen that a lithographic printing plate excellent in scratch resistance and printing durability can be obtained in any of Examples 1 to 10, which are the methods for preparing a lithographic printing plate according to the present disclosure.

The disclosure of Japanese Patent Application No. 2018-140598 filed on July 26, 2018 is incorporated herein by reference in its entirety.
All publications, patent applications, and technical standards referred to in this specification are to the same extent as if each individual publication, patent application, and technical standard were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

61: rotating brush roll, 62: receiving roll, 63: transport roll, 64: transport guide plate, 65: spray pipe, 66: pipeline, 67: filter, 68: plate feeding table, 69: plate discharging table, 70: development Liquid tank, 71: circulation pump, 72: planographic printing plate precursor, 100: planographic printing plate precursor, 104: preheating unit, 105: heating chamber, 106: developing unit, 110: drying unit, 112: carry-in roller, 114: Skewer roller, 116: transport roller, 120: developing tank, 122: transport roller, 124: brush roller, 126: squeeze roller, 128: backup roller, 136: guide roller, 138: skewer roller, D: planographic printing plate precursor Transport direction

Claims

Exposing a lithographic printing plate precursor having an image recording layer on a support, and
a step of performing a development treatment with a developer having a pH of 10 or more and less than 12;
The image recording layer contains a binder having a structural unit represented by the following formula (Bn), a photopolymerization initiator, and a polymerizable compound,
A method for preparing a lithographic printing plate, wherein the developer contains an amphoteric surfactant and a surfactant other than the amphoteric surfactant.

In the formula (Bn), R 1 to R 3 each independently represent a hydrogen atom or an alkyl group, R 4 to R 8 each independently represent a hydrogen atom or a monovalent substituent, and L 1 represents a divalent Represents a linking group.
(4) The method for producing a lithographic printing plate according to (1), wherein the exposing in the exposing step is performed by a laser beam having a wavelength of 760 nm to 1,200 nm.
(4) The method for preparing a lithographic printing plate according to (1), wherein the exposing in the exposing step is performed by a laser beam having a wavelength of 250 nm to 420 nm.
4. The method for producing a lithographic printing plate according to any one of claims 1 to 3, wherein the method does not include a step of washing the lithographic printing plate obtained by the developing treatment after the step of performing the developing treatment.
The method for producing a lithographic printing plate according to any one of claims 1 to 4, wherein the amphoteric surfactant contains a compound represented by the following formula (I) or (II).

In the formulas (I) and (II), R 1 to R 3 each independently represent an alkyl group, and an ester bond (— (C ＝ O)) is formed in the alkyl chain of the alkyl group in R 1 to R 3 . O-), ether bond (-O-), and an amide bond (-NH- (C = O) - ) may have a linking group selected from the group consisting of, R 4 ~ R 6 is Each independently represents an alkyl group, and an ester bond (— (C ＝ O) O—), an ether bond (—O—), and an amide bond (in the alkyl chain of the alkyl group in R 4 to R 6 ) It may have a linking group selected from the group consisting of -NH- (C = O)-), L represents an alkylene group, and A represents a carboxylate ion or a sulfonate ion.
6. The method for preparing a lithographic printing plate according to claim 5, wherein the amphoteric surfactant contains a compound represented by the formula (II).
At least one of R 4 to R 6 has a linking group selected from the group consisting of an ester bond, an amide bond and an ether bond in the alkyl chain of the alkyl group, and A is a carboxylic acid The method for producing a lithographic printing plate according to claim 6, which is an ion.
The surfactant according to any one of claims 1 to 7, wherein the surfactant other than the amphoteric surfactant is at least one surfactant selected from the group consisting of an anionic surfactant and a nonionic surfactant. The method for producing a lithographic printing plate described in 1.
9. The method according to claim 8, wherein the anionic surfactant is a compound having an aromatic ring structure and at least one structure selected from the group consisting of a sulfonate structure, a carboxylate structure, and a phosphate structure. The method for preparing the lithographic printing plate described in the above.
The method for preparing a lithographic printing plate according to claim 9, wherein the anionic surfactant is a compound represented by the following formula (III) or (IV).

In formulas (III) and (IV), R An1 ~ R An10 each independently represent a hydrogen atom or an alkyl group, LAn is an integer of 1 ~ 3, X An 1 and X An2 are each independently sulfone An acid base, a carboxylate group or a phosphate group, wherein the total number of carbon atoms of R An1 to R An5 is 3 or more, and the total number of carbon atoms of R An6 to R An10 is 3 or more.
The method for producing a lithographic printing plate according to any one of claims 8 to 10, wherein the nonionic surfactant is a compound having an aromatic ring structure and an alkyleneoxy chain structure.
The method for preparing a lithographic printing plate according to claim 11, wherein the nonionic surfactant is a compound represented by the following formula (V).
X No -Y No -O- (A No ) p- (B No ) qH (V)
In the formula (V), X No represents an aromatic group, Y No represents a single bond or an alkylene group having 1 to 10 carbon atoms, A No and B No are different groups, and —CH 2 CH 2 Represents O— or —CH 2 CH (CH 3 ) O—, p and q each independently represents an integer of 0 to 100, and the sum of p and q is 2 or more.
(13) The method for preparing a lithographic printing plate according to any one of (1) to (12), wherein the developer contains an organic solvent.
14. The lithographic printing plate according to claim 1, wherein the binder further has a structural unit represented by the following formula (Ac) and a structural unit represented by the following formula (Al). Method of manufacturing.

In the formulas (Ac) and (Al), R Ac and R Al each independently represent a hydrogen atom or a methyl group.