JP5466720B2 - Planographic printing plate precursor and method for producing the same - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor and a method for producing the same.

  The development of technology related to laser exposure and development in lithographic printing is remarkable. In particular, a solid-state laser / semiconductor laser having a light emitting region from the near infrared to the infrared can be easily obtained with a high output and a small size. A laser is very useful as an exposure light source when directly making a plate from digital data of a computer or the like, and the development of a lithographic printing plate corresponding to this is extremely important.

  The recording layer of the positive lithographic printing plate precursor for infrared laser contains, as essential components, an alkali-soluble binder resin and an IR dye that absorbs light and generates heat. The IR dye or the like functions as a development inhibitor that substantially lowers the solubility of the binder resin in the developer by interaction with the binder resin in the unexposed area (image area). On the other hand, in the exposed area (non-image area), the interaction between the IR dye and the binder resin is weakened by the generated heat and dissolves in an alkaline developer to form a lithographic printing plate.

  The basic performance required for the above-described lithographic printing plate precursor is developability that quickly realizes the formation of a clear image area, and conversely, chemical resistance that the recording layer is not dissolved in the unexposed area and is accurately maintained. And improvement in printing durability to increase the printable amount. However, these performances usually conflict with each other, and it is extremely difficult to raise all performance items at the same time. For example, in the printing plate precursor disclosed in the following Patent Documents 1 to 3, it is proposed that the recording layer contains a specific polymer. Usually, when a polymer having a large molecular weight is present in the recording layer, the printing durability and chemical resistance can be improved accordingly. However, the developability tends to be inferior, so that all performance cannot be improved in a balanced manner.

JP 2007-017913 A Japanese Patent No. 4579639 Special table 2010-532488 gazette

  The inventor of the present application has conducted research and development for simultaneously increasing the performance of the above-mentioned characteristic items that are in conflict with each other in view of the technique of the above-mentioned patent document. That is, the present invention realizes high printing durability and chemical resistance in lithographic printing, and also achieves good developability of exposed areas, suppression of running scum, and excellent concentration of developing waste liquid. The purpose is to provide an original plate and a method for producing the same.

The above problems have been achieved by the following means.
(1) An infrared-sensitive positive lithographic printing plate precursor having an image recording layer on the upper side of a support having a hydrophilic surface, wherein the image recording layer comprises poly (vinyl acetal) and amphoteric surface activity A lithographic printing plate precursor comprising an agent and / or an anionic surfactant and an infrared absorber.
(2) An infrared-sensitive positive lithographic printing plate precursor having an image recording layer in which a lower layer and an upper layer are arranged in this order on a support having a hydrophilic surface, wherein the upper layer and / or the lower layer are (1) characterized in that poly (vinyl acetal), an amphoteric surfactant and / or an anionic surfactant, and an infrared absorber are contained in the same layer or in separate layers. The lithographic printing plate precursor described.
(3) The lithographic printing plate precursor as described in (1) or (2), wherein the amphoteric surfactant is represented by any one of the following general formulas (I) to (III).

（一般式（Ｉ）〜（ＩＩＩ）中、Ｒ^１は炭素数６〜２４のアルキル基もしくは特定の連結基を介するアルキル基を表す。Ｒ^２、Ｒ^３はそれぞれ独立に炭素数１〜５のアルキル基を表す。Ｒ^４、Ｒ^５はそれぞれ独立に炭素数１〜５のアルキル基を表す。ただし、Ｒ^４及びＲ^５の少なくとも一方は末端に酸性基もしくはその塩を有する。Ｌ^１は炭素数１〜４の連結基を表す。Ｘ⁻はカルボン酸イオン、スルホン酸イオン、硫酸イオン、ホスホン酸イオン、またはリン酸イオンを表す。）
（４）前記アニオン性界面活性剤が下記一般式（ＩＶ）〜（ＶＩ）のいずれか表わされるものであることを特徴とする（１）又は（２）に記載の平版印刷版原版。

(In General Formulas (I) to (III), R ¹ represents an alkyl group having 6 to 24 carbon atoms or an alkyl group via a specific linking group. R ² and R ³ each independently has 1 to 5 carbon atoms. R ⁴ and R ⁵ each independently represents an alkyl group having 1 to 5 carbon atoms, provided that at least one of R ⁴ and R ⁵ has an acidic group or a salt thereof at the terminal, L ¹ is carbon .X which represents a linking group having 1 to 4 ^- represents a carboxylate ion, sulfonate ion, sulfate ion, phosphonate or phosphate ions).
(4) The lithographic printing plate precursor as described in (1) or (2), wherein the anionic surfactant is any one of the following general formulas (IV) to (VI ) :

（一般式（ＩＶ）〜（ＶＩ）中、Ｒ ^６ は炭素数６〜２４のアルキル基を表す。Ｌ^２はフェニレン基又は単結合を表す。Ｄ^１、Ｅ^１、Ｆ^１はスルホン酸イオンもしくはその塩、または硫酸イオンもしくはその塩を表す。Ｒ^７は炭素数４〜１８のアルキル基を表す。Ｌ^３はフェニレン基またはナフチレン基を表す。Ｒ^８はフェニル基またはナフチル基を表す。Ｌ^４はポリアルキレンオキシ基を表す。）
（５）前記ポリ（ビニルアセタール）の繰り返し単位が、下記一般式（ａ）で表されることを特徴とする（１）〜（４）のいずれか１項に記載の平版印刷版原版。

(In the general formula (IV) ~ (V I) , .D 1, E 1, F 1 R 6 is representative of the .L ² is a phenylene group or a single bond represents an alkyl group having 6 to 24 carbon atoms sulfonate ion Or a salt thereof, or a sulfate ion or a salt thereof, R ⁷ represents an alkyl group having 4 to 18 carbon atoms, L ³ represents a phenylene group or a naphthylene group, and R ⁸ represents a phenyl group or a naphthyl group. ⁴ represents a polyalkyleneoxy group .)
(5) The lithographic printing plate precursor as described in any one of (1) to (4), wherein the repeating unit of the poly (vinyl acetal) is represented by the following general formula (a).

（ここで、ＲおよびＲ’は独立に水素またはアルキルもしくはハロゲン原子であり、Ｒｘはフェノール、ナフトールもしくはアントラセノール基である。）
（６）前記ポリ（ビニルアセタール）の繰り返し単位が、下記一般式（ｂ）で表されることを特徴とする（１）〜（４）のいずれか１項に記載の平版印刷版原版。

(Where R and R ′ are independently hydrogen or an alkyl or halogen atom, and Rx is a phenol, naphthol or anthracenol group.)
(6) The lithographic printing plate precursor as described in any one of (1) to (4), wherein the repeating unit of the poly (vinyl acetal) is represented by the following general formula (b).

（ここで、ＲおよびＲ’は独立に水素またはアルキルもしくはハロゲン原子である。Ｒｙは、下記Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５、及びＲ_６のいずれかを表し、一般式（ａ）で表される樹脂が上記異なるＲｙの一種以上の繰り返し単位を含む共重合体である。
Ｒ_１はアルキル基、シクロアルキル基、またはフェノールもしくはナフトール以外のアリール基であり、
Ｒ_２は前記Ｒｘと同義であり、
Ｒ_３は炭素数２〜６のアルキニル基又はフェニル基である。）
（７）前記界面活性剤を、前記ポリ（ビニルアセタール）１００質量部に対して１〜２０質量部含むことを特徴とする（１）〜（６）のいずれか１項に記載の平版印刷版原版。
（８）（１）〜（７）のいずれか１項に記載の平版印刷版原版の画像記録層を画像露光する露光工程、アルカリ水溶液を用いて現像する現像工程、をこの順で含む平版印刷版の作製方法。
（９）前記アルカリ水溶液がアニオン性界面活性剤またはノニオン性界面活性剤または両性界面活性剤を含むことを特徴とする（８）に記載の平版印刷版の作製方法。
（１０）前記平版印刷版に含まれる両性界面活性剤および／またはアニオン性界面活性剤が、前記アルカリ水溶液に含まれる界面活性剤と同一であることを特徴とする（８）に記載の平版印刷版の作製方法。

(Here, R and R ′ are independently hydrogen, an alkyl, or a halogen atom. Ry represents any of the following R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ , The resin represented by (a) is a copolymer containing one or more repeating units of different Ry.
R ₁ is an alkyl group, a cycloalkyl group, or an aryl group other than phenol or naphthol,
R ₂ has the same meaning as Rx,
R ₃ is a C 2-6 alkynyl group or phenyl group. )
(7) The lithographic printing plate as described in any one of (1) to (6), wherein the surfactant is contained in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the poly (vinyl acetal). Original edition.
(8) Lithographic printing comprising in this order an exposure step for image exposure of the image recording layer of the lithographic printing plate precursor as described in any one of (1) to (7) and a development step for development using an aqueous alkali solution Plate making method.
(9) The method for preparing a lithographic printing plate as described in (8), wherein the alkaline aqueous solution contains an anionic surfactant, a nonionic surfactant or an amphoteric surfactant.
(10) The lithographic printing according to (8), wherein the amphoteric surfactant and / or the anionic surfactant contained in the lithographic printing plate is the same as the surfactant contained in the alkaline aqueous solution. Plate making method.

  The lithographic printing plate precursor of the present invention realizes high printing durability and chemical resistance in lithographic printing, and at the same time, achieves good developability of the exposed area, suppression of running scum, and excellent concentration of phenomenon waste liquid. . Moreover, according to the production method of the present invention, a lithographic printing plate precursor exhibiting the above-described good performance can be produced.

FIG. 1 is a cross-sectional view schematically showing an embodiment in which the recording layer of the planographic printing plate precursor according to the present invention has a single layer structure.

Hereinafter, the present invention will be described in detail.
<Lithographic printing plate precursor>
The planographic printing plate precursor of the present invention has an image recording layer on the upper side of a support having a hydrophilic surface, and the recording layer comprises (a) an acetal resin and (b) a specific surfactant. contains. Note that other layers such as an undercoat layer and a surface protective layer may be further provided on the upper side of the support.

By adopting the above configuration, the reason (action mechanism) for achieving the effects of simultaneously achieving printing durability, chemical resistance, developability, etc. in the present invention includes unclear points, but is as follows. Is estimated.
It is known that amphoteric surfactants and anionic surfactants have higher hydration power and dispersion power than nonionic and cationic surfactants. Increasing the amount of surfactant to increase the developability generally decreases the chemical resistance of the recording layer. However, when amphoteric surfactants and anionic surfactants are used, only a small amount is added. There is an advantage that the influence of deterioration of the printability and chemical resistance is small.
On the other hand, since the surfactant is consumed by the development of the photosensitive material, it is necessary to replenish the surfactant from outside the development system. As a replenishment method, there are a method of replenishing a developer containing an activator and a method of containing a necessary amount of an activator in a light-sensitive material. By including an activator in the light-sensitive material as in the present invention and applying it in combination with a specific acetal resin, the amount of developed light-sensitive material can be the amount of activator consumed by development. It is considered that good developability can be maintained stably for a long period of time.
Hereinafter, preferred embodiments of the present invention will be described.

<Acetal resin>
The recording layer constituting the lithographic printing plate precursor according to the invention contains an acetal resin.
Acetal resins applied in the present invention include available poly (vinyl acetal) s, and include at least 50 mol% (50 mol% to 70 mol%, more typically at least 60 mol%) of repeating units. %) Is an acetal-containing repeating unit. In contrast, non-acetal-containing repeat units can have the same or different pendant phenolic groups, or non-acetal-containing repeat units can be repeat units without pendant phenolic groups. Alternatively, the non-acetal-containing repeat unit can include both types of repeat units. For example, poly (vinyl acetal) can have repeating units that contain itaconic acid or crotonic acid groups. Furthermore, if there are repeating units containing pendant phenolic groups, those repeating units can have different pendant phenolic groups [eg, poly (vinyl acetal) has acetal-containing repeating units. And two or more different types of repeating units have different pendant phenolic groups].

In yet another embodiment, low molar amounts (20 mol%) in poly (vinyl acetal)
Less than) acetal groups can be reacted with cyclic acid anhydrides or isocyanate compounds such as toluenesulfonyl isocyanate.

  Examples of the poly (vinyl acetal) in the present invention include compounds containing a repeating unit represented by the following general formula (a).

ここで、ＲおよびＲ’は独立に水素またはアルキルもしくはハロゲン原子であり、Ｒｘはフェノール、ナフトールもしくはアントラセノール基である。

Here, R and R ′ are independently hydrogen or an alkyl or halogen atom, and Rx is a phenol, naphthol or anthracenol group.

  In the general formula (a), R and R ′ are preferably independently a hydrogen atom, a substituted or unsubstituted linear or branched alkyl group having 1 to 6 carbon atoms (for example, methyl, ethyl, n- Propyl, n-butyl, n-pentyl, n-hexyl, chloromethyl, trichloromethyl, iso-propyl, iso-butyl, t-butyl, iso-pentyl, neo-pentyl, 1-methylbutyl and iso-hexyl groups) Or a substituted or unsubstituted cycloalkyl ring having 3 to 6 carbon atoms in the ring (eg, cyclopropyl, cyclobutyl, cyclopentyl, methylcyclohexyl and cyclohexyl groups), or a halo group (eg, fluoro, chloro, bromo, Or iodine). Typically, R and R 'are independently hydrogen, or a substituted or unsubstituted methyl group, or chloro group, or, for example, they are independently hydrogen or unsubstituted methyl.

  Rx is preferably a substituted or unsubstituted phenol, substituted or unsubstituted naphthol, or substituted or unsubstituted anthracenol group. These phenol, naphthol and anthracenol groups are further hydroxy substituents, methoxy, alkoxy, aryloxy, thioaryloxy, halomethyl, trihalomethyl, halo, nitro, azo, thiohydroxy, thioalkoxy, cyano, amino , Carboxy, ethenyl, carboxyalkyl, phenyl, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl and heteroalicyclic groups can have up to 3 further substituents. For example, Rx can be an unsubstituted phenol or naphthol group, such as a 2-hydroxyphenyl or hydroxynaphthyl group. In addition, the said preferable substituent may be substituted by the carbon atom of Formula (a) with the predetermined | prescribed coupling group (For example, C1-C3 alkylene group).

  Thus, poly (vinyl acetals) can have a variety of other repeating units in addition to those represented by structure (a), but generally at least 50 mole percent of the repeating units are structured The same or different repeating units represented by (a).

  More preferably, poly (vinyl acetal) includes a compound containing a repeating unit represented by the following general formula (b).

ここで、ＲおよびＲ’前記一般式（ａ）と同様である。

Here, R and R ′ are the same as those in the general formula (a).

The polymerization ratio m of the monomer (Ia) in which Ry = R ₁ is preferably 5 to 40 mol%, and more preferably 15 to 35 mol%.
Preferably the polymerization ratio n of Ry = _{R 2} a monomer (Ib) is 10 to 60 mol%, more preferably 20 to 40 mol%.
further,
The polymerization ratio p of the monomer (Ic) in which Ry = R ₃ is preferably 0 to 20 mol%, and more preferably 0 to 10 mol%.

R ₁ is an alkyl group, a cycloalkyl group, or an aryl group other than phenol or naphthol. Preferably, a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms (for example, methyl, ethyl, n-propyl, iso-propyl, t-butyl, n-butyl, n-pentyl, n -Hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, methoxymethyl, chloromethyl, trichloromethyl, benzyl, cinnamoyl, iso-propyl, iso-butyl, s- Butyl, t-butyl, iso-pentyl, neo-pentyl, 1-methylbutyl and iso-hexyl groups), substituted or unsubstituted cycloalkyl rings having 3 to 6 carbon atoms in the ring (eg, cyclopropyl , Cyclobutyl, cyclopentyl, methylcyclohexyl and cyclohexyl groups), or Substituted or unsubstituted aryl groups having 6 or 10 carbon atoms in an aromatic ring other than nor or naphthol (eg substituted or unsubstituted phenyl such as phenyl, xylyl, tolyl, p-methoxyphenyl, 3-chlorophenyl and naphthyl) And a naphthyl group). Typically, R ¹ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.

R ₂ is the same as Rx in the formula (a).

R ₃ is preferably a substituted or unsubstituted alkynyl group having 2 to 4 carbon atoms (for example, ethynyl group), or a substituted or unsubstituted phenyl group (for example, phenyl, 4-carboxyphenyl, carboxyalkyleneoxyphenyl and carboxy). Alkylphenyl group). Typically, R ³ is a carboxyalkylphenyl group, a 4-carboxyphenyl or carboxyalkyleneoxyphenyl group, or other carboxy-containing phenyl group.

The poly (vinyl acetal) of this embodiment can be at least a tetramer depending on the number of different repeating units present. For example, there may be many types of repeating units that are different from any of the previously defined classes of repeating units of structure (Ia) to structure (Ic). For example, the poly (vinyl acetal) of general formula (a) can have repeating units of structure (Ia) having different R ₁ groups. Such diversity of repeat units can also be said for those represented by any of structure (Ia) to structure (Ic).

  The polymer of this embodiment can contain repeating units other than those defined above, and such repeating units will be readily apparent to those skilled in the art. That is, in its broadest sense, it is not limited to defined repeating units, but in some embodiments, only the above repeating units are present in general formula (a).

[Id :-( CHR-CR < ¹ > R < ⁴ >)-] is mentioned as a copolymer unit which may be coexistent. R ⁴ is preferably a —O—C (═O) —R ⁵ group, wherein R ⁵ is a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, as defined for R ¹ above. Or a substituted or unsubstituted aryl group having 6 or 10 carbon atoms in the aromatic ring. Typically, R ⁵ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, such as an unsubstituted methyl group. Alternatively, [Ie:-(CHR-CR'OH)-] can be mentioned. The copolymerization ratio of the repeating unit (Id) is preferably 1 to 20 mol%, and more preferably 1 to 15 mol%. The copolymerization ratio of the repeating unit (Ie) is preferably 5 to 60 mol%, and more preferably 15 to 55 mol%.

R ⁵ is preferably a hydroxy group.

  Although content of the acetal resin in a recording layer is not specifically limited, It is preferable that it is 10-99 mass% with respect to the total amount of solid content, and it is more preferable that it is 30-95 mass%. Many embodiments include the acetal resin in an amount of 50-90% by weight of the total composition or layer dry weight.

  The poly (vinyl acetals) described herein can be prepared using known starting materials and reaction conditions such as those described in US Pat. No. 6,541,181 (supra). For example, acetalization of polyvinyl alcohol is described, for example, in US Pat. No. 4,665,124 (Dhillon et al.), US Pat. No. 4,940,646 (Pawlowski), US Pat. No. 5,169,898. Description (Walls et al.), US Pat. No. 5,700,619 (Dwars et al.) And US Pat. No. 5,792,823 (Kim et al.), And Japanese Patent Application Laid-Open No. 09-328519 ( The reaction product can be obtained by proceeding according to standard methods known in Yoshishina).

  The weight average molecular weight (Mw) of the acetal resin is not particularly limited, but is preferably 5,000 to 300,000, and more preferably 20,000 to 50,000.

Poly (vinyl acetals) are described in US Pat. Nos. 6,255,033 and 6,541,181 and in WO 2004/081662. The same or similar poly (vinyl acetal) is described in EP 1 627 732 (Hatanaka et al.) And US 2005/0214677 (Nagashima) and US 2005/2005. No. 0214678 (Nagashima) (all the poly (vinyl acetals) described in these references are incorporated herein) by general formulas (I) and (II) comprising structural units (a) to (e) Have been described.
Unless otherwise specified, the molecular weight and the degree of dispersion are values measured using a GPC (gel filtration chromatography) method, and the molecular weight is a polystyrene-reduced weight average molecular weight. The gel packed in the column used in the GPC method is preferably a gel having an aromatic compound as a repeating unit, and examples thereof include a gel made of a styrene-divinylbenzene copolymer. It is preferable to use 2 to 6 columns connected together. Examples of the solvent used include ether solvents such as tetrahydrofuran and amide solvents such as N-methylpyrrolidinone. The measurement is preferably performed at a solvent flow rate in the range of 0.1 to 2 mL / min, and most preferably in the range of 0.5 to 1.5 mL / min. By performing the measurement within this range, the apparatus is not loaded and the measurement can be performed more efficiently. The measurement temperature is preferably 10 to 50 ° C, most preferably 20 to 40 ° C. Note that the column and carrier to be used can be appropriately selected according to the physical properties of the polymer compound that is symmetrical to the measurement.

<Phenolic resin>
A phenolic resin can also be used for the recording layer in the present invention. Examples of such phenolic resins include phosphor resins, such as a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, and a condensation of m / p-mixed cresol and formaldehyde. Polymers, condensation polymers of phenol and cresol (m-, p- or m- / p- mixtures) and formaldehyde, and condensation copolymers of pyrogallol and acetone. Furthermore, a copolymer obtained by copolymerizing a compound containing a phenol group in the side chain can also be used. Mixtures of such polymer binders can also be used.

  Also useful are novolak resins having a weight average molecular weight of at least 1500 and a number average molecular weight of at least 300. Generally, the weight average molecular weight is in the range of 3,000 to 300,000, the number average molecular weight is in the range of 500 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1. It is in the range of 1-10.

  Specific mixtures of the first polymer binders described above can be used, and examples of such mixtures include mixtures of one or more poly (vinyl acetals) and one or more phenolic resins. For example, a mixture of one or more poly (vinyl acetals) and one or more phosphos or resole resins (or phosphos and resole resins) can be used.

<Acid group-containing polymer>
Examples of the second polymer binder include the following classes of polymers having acidic groups contained in (1) to (5) shown below on the main chain and / or side chains (pendant groups).
(1) Sulfonamide group (—SO ₂ NH—R),
(2) Acid groups based on substituted sulfonamides (herein referred to as active imide groups) [eg -SO ₂ NHCOR, SO ₂ NH
_{SO 2 R, -CONHSO 2 R]} ,
(3) Carboxylic acid group (—CO ₂ H),
(4) sulfone group _(-SO 3 H), and (5) phosphoric acid group (-OPO ₃ H _2).

  R in said group (1)-(5) represents hydrogen or a hydrocarbon group.

  A typical second polymer binder having a sulfonamide group of the substituent (1) includes, for example, a polymer composed of a minimum constituent unit as a main component derived from a compound having a sulfonamide group. Therefore, as an example of such a compound, a compound having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and at least one polymerizable unsaturated group in the molecule. Is mentioned. These compounds include m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, and N- (p-aminosulfonylphenyl) acrylamide. Therefore, polymerizable monomers having a sulfonamide group, such as homopolymers and copolymers such as m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, or N- (p-aminosulfonylphenyl) acrylamide it can.

The second polymer binder having an active imide group of the substituent (2) is a polymer including a repeating unit derived from a compound having an active imide group as a main component. Examples of such compounds include polymerizable unsaturated compounds having a moiety defined by the structural formula — (CO) (NH) (SO ₂ ) —.

  N- (p-toluenesulfonyl) methacrylamide and N- (p-toluenesulfonyl) acrylamide are examples of such polymerizable compounds.

  The second polymer binder having any one of the above substituents (3) to (5) is reacted with an ethylenically unsaturated polymerizable monomer having a desirable acidic group or a group that can be converted into the acidic group after polymerization. Can be easily prepared.

  With respect to the minimum structural unit having an acidic group selected from the above (1) to (5), it is not necessary to use only one kind of acidic group in the polymer, and depending on the embodiment, at least two kinds of acidic groups are used. It may be useful to have a group. Of course, not all repeating units in the second polymeric binder must have one of the acidic groups, but usually at least 10 mole percent, typically at least 20 mole percent Consists of repeating units having one of the above acidic groups.

  The acidic group-containing polymer can have a weight average molecular weight of at least 2,000 and a number average molecular weight of at least 500. Typically, the weight average molecular weight is in the range of 5,000 to 300,000, the number average molecular weight is in the range of 800 to 250,000, and the degree of dispersion (weight average molecular weight / number average molecular weight) is 1. Within the range of 1-10.

  You may use an acidic group containing polymer together with 1 type, or 2 or more types of 1st polymer binders. Although content of an acidic group containing polymer is not specifically limited, It is preferable that it is at least 1 mass% and 50 mass% or less, and it is more preferable that it is the quantity of 5-30 mass%.

  In addition, in the description of group (atom group) in this specification, the description which does not describe substitution and unsubstituted includes the thing which has a substituent with the thing which does not have 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, the *** compound is used to mean a salt thereof, an ion thereof, and the like in addition to the compound itself. Typically, it means the compound and / or its salt. The same applies to the surfactant described below, and the compound defined therein may exist as an ion without a counter ion or may be a salt.

<Surfactant>
-Amphoteric surfactant Preferred amphoteric surfactants include those represented by any one of the following general formulas (I) to (III).

R ¹ represents an alkyl group having 6 to 24 carbon atoms or an alkyl group via a specific linking group. Among these, a linear alkyl group having 8 to 18 carbon atoms, an alkyl group having 8 to 18 carbon atoms or via a specific linking group is preferable, and an amide group is preferable as the specific linking group.
R ² and R ³ each independently represents an alkyl group having 1 to 5 carbon atoms. Of these, a methyl group, an ethyl group, and a 2-hydroxyethyl group are preferable.
R ⁴ and R ⁵ each independently represents an alkyl group having 1 to 5 carbon atoms having an acidic group or a salt thereof (preferably a carboxylic acid or a salt thereof) at the terminal. Of these, a 2-carboxymethyl group, a 2-carboxyethyl group, a 2-carboxypropyl group, a carboxypolyethylene oxide group, and a carboxypolypropylene oxide group are preferable.
L ¹ represents a linking group having 1 to 4 carbon atoms. Of these, an alkylene group is preferable, and a methylene group, an ethylene group, and a propylene group are preferable.
X ⁻ represents a carboxylate ion (or a salt thereof), a sulfonate ion (or a salt thereof), a sulfate ion (or a salt thereof), a phosphonate ion (or a salt thereof), or a phosphate ion (or a salt thereof).
The anionic group may form a salt, and examples of the counter ion include sodium ion, potassium ion, magnesium ion, and calcium ion.

  Specific examples of amphoteric surfactants include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, and N-tetradecyl-N, N-. Examples include betaine type.

Specific examples of the amphoteric surfactant represented by the general formula (I) include Levon 2000, Levon LD36 (manufactured by Sanyo Chemical Industries, Ltd.), Texnol R2 (Nihon Emulsifier Co., Ltd.) AM-301. AM-3130N (above, manufactured by Nikko Chemicals Co., Ltd.), Amphitole 20AB, Amphitole 20BS, Amphitole 24B, Amphitole 55AB, Amphitole 86B (above, manufactured by Kao Corp.), Adeka Anhhot AB-35L, Adeka Anhhot PB-30L (above , Manufactured by ADEKA Co., Ltd.), Anholex CB-1, Ampholex LB-2 (above, manufactured by Miyoshi Oil & Fats Co., Ltd.), Enagicol C-30B, Enagicol L-30B (above, manufactured by Lion Corp.), ovazoline BC, Obazoline CAB-30, Obazolin LB-SF, Obazolin LB ( Toho Chemical Industry Co., Ltd.), Softazolin CPB-R, Softazolin CPB, Softazolin LPB-R, Softazolin LPB, Softazolin MPB, Softazolin PKBP (Manufactured by Kawaken Fine Chemical Co., Ltd.), Nissan Annon BDC-S, Nissan Anon BDF-R, Nissan Anon BDF-SF, Nissan Anon BF, Nissan Anon BL-SF, Nissan Anon BL (manufactured by NOF Corporation) and the like can be mentioned.
Specific examples of the amphoteric surfactant represented by the general formula (II) include Amphithol 20N (manufactured by Kao Corporation), Softazoline LAO-C, Softazolin LAO (above, Kawaken Fine Chemical Co., Ltd.), Unisafe Examples include A-OM (manufactured by NOF Corporation), kachinal AOC (manufactured by Toho Chemical Industry Co., Ltd.), and Aromox DMC-W (manufactured by Lion Corporation).
Specific examples of the amphoteric surfactant represented by the above general formula (III) include Enagicol DP-30 (manufactured by Lion Co., Ltd.), Delifat 160C (manufactured by Cognis Japan Co., Ltd.), Pionin C158G (Takemoto Oil and Fat ( Etc.).

  Furthermore, specific examples of the amphoteric surfactant are exemplified below by chemical structural formulas.

  The compounds represented by the general formulas (I) to (III) can be used alone or in combination.

  Other examples of zwitterionic surfactants include amine oxides such as alkyldimethylamine oxide, betaines such as alkyl betaines, fatty acid amidopropyl betaines, alkyl imidazoles, and sodium alkylamino fatty acids. Amino acid systems such as

  In particular, alkyldimethylamine oxide which may have a substituent, alkylcarboxybetaine which may have a substituent, and alkylsulfobetaine which may have a substituent are preferably used. Specific examples thereof include compounds represented by formula (2) in paragraph No. [0256] of JP-A-2008-203359, formulas (I) and (II) in paragraph No. [0028] of JP-A-2008-276166. ), Compounds represented by formula (VI), and compounds described in paragraphs [0022] to [0029] of JP-A-2009-47927.

  As the zwitterionic surfactant used in the developer, a compound represented by the following general formula (A1), a compound represented by the general formula (A2), and a compound represented by the general formula (A3) are preferable.

In formulas (A1) to (A3), R ¹ , R ¹¹ and R ¹⁵ each independently represent an alkyl group having 8 to 20 carbon atoms or a linking group having 8 to 20 carbon atoms in total. R ² , R ³ , R ¹² and R ¹³ each independently represents a group containing a hydrogen atom, an alkyl group or an ethylene oxide group. R ⁴ and R ¹⁴ each independently represents a single bond or an alkylene group. Further, two groups out of R ¹ , R ² , R ³ and R ⁴ may be bonded to each other to form a ring structure, and two groups out of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are They may combine to form a ring structure. L ¹ and L ² represent a linking group having 1 to 4 carbon atoms. Of these, an alkylene group is preferable, and a methylene group, an ethylene group, and a propylene group are preferable. X represents a hydrogen atom or an alkali metal (preferably sodium or potassium).

In the compound represented by the general formula (A1) or the compound represented by the general formula (A2) and the general formula (A3), the hydrophobic portion increases as the total carbon number increases, and the solubility in an aqueous developer is increased. Decreases. In this case, the solubility is improved by mixing an organic solvent such as alcohol to help dissolution into water as a dissolution aid, but if the total carbon number becomes too large, the surface activity is within the proper mixing range. The agent cannot be dissolved. Therefore, the total number of carbon atoms of R ^{1 to} R ⁴ or R ^{11 to} R ¹⁴ and R ¹⁵ is preferably 10 to 40, more preferably 12 to 30.

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

When R ² or R ¹² is an alkyl group, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. Either a straight chain or a branched chain may be used, but a straight chain alkyl group is preferable.

When R ³ or R ¹³ is an alkyl group, the carbon number is preferably 1 to 5, and particularly preferably 1 to 3. Either a straight chain or a branched chain may be used, but a straight chain alkyl group is preferable.
Examples of the group containing ethylene oxide represented by R ³ or R ¹³ include a group represented by —Ra (CH ₂ CH ₂ O) _n Rb. Here, Ra represents a single bond, an oxygen atom or a divalent organic group (preferably having 10 or less carbon atoms), Rb represents a hydrogen atom or an organic group (preferably having 10 or less carbon atoms), and n is 1 to 10 Represents an integer.

When R ⁴ and R ¹⁴ are alkylene groups, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. Either a straight chain or a branched chain may be used, but a linear alkylene group is preferable.
The compounds represented by the general formulas (A1) to (A3) preferably have an amide bond, and more preferably have an amide bond as a linking group for R ¹ or R ¹¹ .
Representative examples of the compound represented by the general formula (A1) or the compound represented by the general formula (A2) are shown below, but the present invention is not limited thereto.

The compounds represented by the formulas (A1) to (A3) can be synthesized according to a known method. Moreover, it is also possible to use what is marketed. As a commercially available product, examples of the compound represented by the formula (A1) include SOFTAZOLIN LPB, SOFTAZOLIN LPB-R, Vista MAP, Takemoto Oil & Fats Takesurf C-157L manufactured by Kawaken Fine Chemicals. Examples of the compound represented by the formula (A2) include SOFTAZOLIN LAO manufactured by Kawaken Fine Chemical Co., Ltd., Amorgen AOL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and the like.
Zwitterionic surfactants may be used alone or in combination of two or more in the developer.

-Anionic surfactant As a preferable anionic surfactant, what is represented by either of the following general formula (IV)-(VI ) is mentioned.

（一般式（ＩＶ）〜（ＶＩ）中、Ｒ ^６ は炭素数６〜２４のアルキル基を表す。Ｌ^２はフェニレン基又は単結合を表す。Ｄ^１、Ｅ^１、Ｆ^１はスルホン酸イオンもしくはその塩、または硫酸イオンもしくはその塩を表す。Ｒ^７は炭素数４〜１８のアルキル基を表す。Ｌ^３はフェニレン基またはナフチレン基を表す。Ｒ^８はフェニル基またはナフチル基を表す。Ｌ^４はポリアルキレンオキシ基を表す。）

(In the general formula (IV) ~ (V I) , .D 1, E 1, F 1 R 6 is representative of the .L ² is a phenylene group or a single bond represents an alkyl group having 6 to 24 carbon atoms sulfonate ion Or a salt thereof, or a sulfate ion or a salt thereof, R ⁷ represents an alkyl group having 4 to 18 carbon atoms, L ³ represents a phenylene group or a naphthylene group, and R ⁸ represents a phenyl group or a naphthyl group. ⁴ represents a polyalkyleneoxy group .)

  Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates. , Alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates, sulfated castor oil , Sulfated beef tallow oil, fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates Tell salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene-anhydrous Partially saponified products of maleic acid copolymer, partially saponified products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensates, aromatic sulfonates, aromatic substituted polyoxyethylene sulfonates, etc. Is mentioned. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

  As the anionic surfactant used in the treatment liquid of the present invention, an anionic surfactant containing a sulfonic acid or a sulfonate is particularly preferable. Anionic surfactants can be used alone or in combination.

  In the present invention, the content of the amphoteric or anionic surfactant is not particularly limited, but is more than 1% by mass and less than 20% by mass with respect to the total solid content of the layer containing the amphoteric or anionic surfactant (in the example, the upper layer). The content is preferably 3 to 15% by mass, and more preferably 5 to 10% by mass. By setting it as the said lower limit or more, generation | occurrence | production of running | fogging deficiency can be effectively suppressed especially and it is preferable. By setting it to the upper limit value or less, it is possible to sufficiently ensure film reduction and printing durability. In terms of the relationship with the specific polyvinyl acetal, from the same viewpoint, it is preferably 0.5 to 18 parts by mass and more preferably 1 to 16 parts by mass with respect to 100 parts by mass. By setting it as the said lower limit or more, generation | occurrence | production of running | fogging deficiency can be effectively suppressed especially and it is preferable.

Other surfactants The specific developer may contain nonionic surfactants, cationic surfactants and the like other than those described above as long as the effects of the present invention are not impaired.

Nonionic surfactants include polyethylene glycol type higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, polyethylene glycol adducts of aromatic compounds, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, Higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. And polyhydric alcohol glycerol fatty acid ester, pentaerythritol fatty acid ester, Rubitoru and fatty acid esters of sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.
The nonionic surfactant preferably includes a nonionic aromatic ether surfactant, and is an adduct of benzene or naphthalene that may have a non-dissociable substituent, or ethylene oxide and / or propylene oxide of naphthalene. It is more preferable. This surfactant may be used individually by 1 type, or may be used in combination of 2 or more type.

  Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

Even when a nonionic surfactant or a cationic agent is used in combination, it is preferable that the content of the amphoteric surfactant or anionic surfactant is the largest. The amphoteric surfactant or anionic surfactant is the total amount of the surfactant. Is preferably 50% by mass or more, and more preferably 60% by mass or more.
For the amphoteric surfactant, reference can be made to JP-A-4-13149, JP-A-59-121044 and the like.

  The content of these other surfactants is preferably 0.01 to 10% by mass and more preferably 0.01 to 5% by mass with respect to the total solid content of the recording layer.

<Infrared absorber>
The lithographic printing plate precursor according to the invention contains an infrared absorber in its recording layer. The infrared absorber is not particularly limited as long as it is a dye that absorbs infrared light and generates heat, and various dyes known as infrared absorbers can be used.
As the infrared absorber that can be used in the present invention, commercially available dyes and known ones described in literature (for example, “Dye Handbook” edited by Organic Synthetic Chemistry Association, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. In the present invention, among these dyes, those that absorb at least infrared light or near-infrared light are preferable because they are suitable for use in lasers that emit infrared light or near-infrared light, and cyanine dyes are particularly preferred. preferable.

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes.

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , X ² -L ¹ or a group shown below. X ² represents an oxygen atom or a sulfur atom. L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.

In the above formula, Xa ^- has Za described later ^- has the same definition as, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted 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 storage stability of the photosensitive layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned.
Y ¹ and Y ² 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 each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups.
R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in the structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion from the storage stability of the photosensitive layer coating solution, and particularly preferably a perchlorate ion, a hexagonal ion. Fluorophosphate ion and aryl sulfonate ion.

Specific examples of the cyanine dye represented by the general formula (a) that can be suitably used include paragraph numbers [0017] to [0019] of JP-A No. 2001-133969 and paragraph numbers of JP-A No. 2002-40638. [0012] to [0038] and paragraphs [0012] to [0023] described in JP-A No. 2002-23360.
The cyanine dye A shown below is particularly preferable as the infrared absorber.

赤外線吸収剤を添加する際の添加量としては、全固形分に対し、０．０１〜５０質量％であることが好ましく、０．１〜３０質量％であることがより好ましく、１．０〜３０質量％であることが特に好ましい。添加量が０．０１質量％以上であると、高感度となり、また、５０質量％以下であると、層の均一性が良好であり、層の耐久性に優れる。

As an addition amount at the time of adding an infrared absorber, it is preferable that it is 0.01-50 mass% with respect to the total solid, It is more preferable that it is 0.1-30 mass%, 1.0- It is especially preferable that it is 30 mass%. When the addition amount is 0.01% by mass or more, high sensitivity is obtained, and when it is 50% by mass or less, the uniformity of the layer is good and the durability of the layer is excellent.

<Other alkali-soluble resins>
In the present invention, the term “alkali-soluble” refers to an alkaline aqueous solution having a pH of 8.5 to 13.5 (preferably 8.5 to 10.8, more preferably 9.0 to 10.0), which is processed for standard development time. Means soluble.
The other alkali-soluble resin used in the recording layer is not particularly limited as long as it has a property of being dissolved when contacted with an alkaline developer, but a phenolic hydroxyl group may be present on the main chain and / or side chain in the polymer. Those having an acidic functional group such as a sulfonic acid group, a phosphoric acid group, a sulfonamide group, and an active imide group are preferable, and contain 10 mol% or more of the monomer having an acidic functional group imparting alkali solubility. Resin is mentioned, The resin which contains 20 mol% or more is more preferable. When the copolymerization component of the monomer that imparts alkali solubility is 10 mol% or more, sufficient alkali solubility is obtained and the developability is excellent.
Furthermore, as described in U.S. Pat. No. 4,123,279, a phenol having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin; Examples thereof include condensation polymers with formaldehyde. Moreover, it is preferable that the weight average molecular weight (Mw) is 500 or more, and it is more preferable that it is 1,000-700,000. Moreover, it is preferable that the number average molecular weight (Mn) is 500 or more, and it is more preferable that it is 750-650,000. The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The other alkali-soluble resin preferably has a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more, a weight average molecular weight of 5,000 to 300,000, and a number average molecular weight of 800 to 250. Is more preferable. The dispersity (weight average molecular weight / number average molecular weight) of the other alkali-soluble resin is preferably 1.1-10.
Other alkali-soluble resins optionally contained in the recording layer may be used alone or in combination of two or more.
The content of the other alkali-soluble resin with respect to the total solid content of the recording layer in the present invention may be used in an addition amount of 0 to 98% by mass. Moreover, it can contain in the ratio of 80 mass parts or less with respect to 100 mass parts of said (A) star-shaped polymers.

<Water-insoluble and alkali-soluble resin>
The recording layer according to the present invention preferably contains a water-insoluble and alkali-soluble resin. By containing the alkali-soluble resin, an interaction is formed between the infrared absorber and the polar group of the alkali-soluble resin, and a positive-type photosensitive layer is formed. Including those mentioned above, for example, polyamide resin, epoxy resin, polyacetal resin, acrylic resin, methacrylic resin, polystyrene resin, novolac type phenol resin and the like can be preferably exemplified.
The alkali-soluble resin that can be used in the present invention is not particularly limited as long as it has a property of dissolving when contacted with an alkaline developer, but contains an acidic group in the main chain and / or side chain in the polymer. It is preferable that the polymer is a homopolymer, a copolymer thereof, or a mixture thereof.
The alkali-soluble resin having such an acidic group preferably has a functional group such as a phenolic hydroxyl group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a sulfonamide group, or an active imide group. Therefore, such a resin can be suitably produced by copolymerizing a monomer mixture containing one or more ethylenically unsaturated monomers having the functional group. Preferred examples of the ethylenically unsaturated monomer having a functional group include, in addition to acrylic acid and methacrylic acid, a compound represented by the following formula and a mixture thereof. In the following formula, R represents a hydrogen atom or a methyl group.

  The alkali-soluble resin that can be used in the present invention is preferably a polymer compound obtained by copolymerizing another polymerizable monomer in addition to the polymerizable monomer. The copolymerization ratio in this case is 10 mol of a monomer that imparts alkali solubility such as a monomer having a functional group such as a phenolic hydroxyl group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a sulfonamide group, or an active imide group. %, Preferably 20 mol% or more. When the copolymerization component of the monomer that imparts alkali solubility is 10 mol% or more, sufficient alkali solubility is obtained and the developability is excellent.

Examples of other polymerizable monomers that can be used include the compounds listed below.
Alkyl acrylates and alkyl methacrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. Acrylamide or methacrylamide such as acrylamide, methacrylamide, N-methylacrylamide, N-ethylacrylamide, N-phenylacrylamide, etc. Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate. Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene. Other nitrogen atom-containing monomers such as N-vinylpyrrolidone, N-vinylpyridine, acrylonitrile and methacrylonitrile. N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-phenylmaleimide, N-2-methylphenylmaleimide, N-2,6-diethylphenylmaleimide, N-2-chlorophenylmaleimide, Maleimides such as N-cyclohexylmaleimide, N-laurylmaleimide, N-hydroxyphenylmaleimide and the like.
Among these other ethylenically unsaturated monomers, (meth) acrylic acid esters, (meth) acrylamides, maleimides, and (meth) acrylonitrile are preferably used.

  Moreover, as an alkali-soluble resin, a novolak resin is mentioned preferably as mentioned above.

The water-insoluble and alkali-soluble resin preferably has a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more, a weight average molecular weight of 5,000 to 300,000, and a number average molecular weight of 800 to More preferably, it is 250,000. Moreover, it is preferable that the dispersity (weight average molecular weight / number average molecular weight) of the alkali-soluble resin is 1.1 to 10.
The alkali-soluble resin in the recording layer of the image recording material of the present invention may be used alone or in combination of two or more.
In the present invention, the content of the alkali-soluble resin with respect to the total solid content of the recording layer is preferably 2.0 to 99.5% by mass in the total solid content, and is 10.0 to 99.0% by mass. It is more preferable that the content is 20.0 to 90.0% by mass. When the addition amount of the alkali-soluble resin is 2.0% by mass or more, the recording layer (photosensitive layer) is excellent in durability, and when it is 99.5% by mass or less, both sensitivity and durability are excellent. .

<Other additives>
(Acid generator)
The image recording layer preferably contains an acid generator from the viewpoint of improving sensitivity.
In this invention, an acid generator is a compound which generate | occur | produces an acid with light or a heat | fever, and points out the compound which decomposes | disassembles and generate | occur | produces an acid by infrared irradiation or a heating of 100 degreeC or more. The acid generated is preferably a strong acid having a pKa of 2 or less, such as sulfonic acid and hydrochloric acid. The acid generated from the acid generator functions as a catalyst, the chemical bond in the acid-decomposable group is cleaved to become an acid group, and the solubility of the recording layer in an aqueous alkaline solution is further improved.

Examples of the acid generator suitably used in the present invention include onium salts such as iodonium salts, sulfonium salts, phosphonium salts, and diazonium salts. Specific examples include compounds described in US Pat. No. 4,708,925 and JP-A-7-20629. In particular, iodonium salts, sulfonium salts, and diazonium salts having a sulfonate ion as a counter ion are preferable. Examples of the diazonium salt include diazonium compounds described in U.S. Pat. No. 3,867,147, diazonium compounds described in U.S. Pat. No. 2,632,703, and JP-A-1-102456 and JP-A-1-102457. The diazo resin described in the publication is also preferable. Also preferred are benzyl sulfonates described in US Pat. No. 5,135,838 and US Pat. No. 5,200,544. Furthermore, active sulfonic acid esters and disulfonyl compounds described in JP-A-2-100054, JP-A-2-100055 and Japanese Patent Application No. 8-9444 are also preferable. In addition, haloalkyl-substituted S-triazines described in JP-A-7-271029 are also preferable.
Further, the compound described as “acid precursor” in JP-A-8-220552 or “(a) a compound capable of generating an acid upon irradiation with active light” in JP-A-9-171254 And the like can be applied as the acid generator of the present invention.

Among these, from the viewpoint of sensitivity and stability, it is preferable to use an onium salt compound as the acid generator. Hereinafter, the onium salt compound will be described.
Examples of the onium salt compound that can be suitably used in the present invention include compounds known as compounds that generate an acid by being decomposed by thermal energy generated from an infrared absorber upon exposure to infrared light. Examples of the onium salt compound suitable for the present invention include known thermal polymerization initiators and compounds having an onium salt structure described below having a bond with small bond dissociation energy from the viewpoint of sensitivity.
Examples of the onium salt suitably used in the present invention include known diazonium salts, iodonium salts, sulfonium salts, ammonium salts, pyridinium salts, azinium salts, and the like. Among them, triarylsulfonium or diaryliodonium sulfonic acid Salts, carboxylates, BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ^{— and the} like are preferable.
Specific examples of the azinium salt compound include compounds described in paragraph numbers [0047] to [0056] of JP-A-2008-195018. The N—O bond described in JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, and JP-B-46-42363 is also disclosed. A group of compounds having the above is also suitably used as the acid generator in the present invention.
When the acid generator is added to the recording layer, the preferable addition amount is 0.01 to 50% by weight, preferably 0.1 to 40% by weight, more preferably 0.5 to 0.5% by weight based on the total solid content of the recording layer. It is in the range of 30% by mass. When the addition amount is in the above range, an improvement in sensitivity, which is an effect of addition of an acid generator, is observed, and generation of a residual film in a non-image area is suppressed.

(Acid growth agent)
An acid multiplication agent may be added to the recording layer in the present invention.
The acid proliferating agent in the present invention is a compound substituted with a relatively strong acid residue, and is a compound that is easily eliminated in the presence of an acid catalyst to newly generate an acid. That is, it decomposes by an acid catalytic reaction and generates an acid again (hereinafter referred to as ZOH in the general formula). One or more acids are increased in one reaction, and the sensitivity is dramatically improved by increasing the acid concentration at an accelerated rate as the reaction proceeds. The strength of the generated acid is 3 or less as an acid dissociation constant (pKa), and preferably 2 or less. If the acid is weaker than this, an acid-catalyzed elimination reaction cannot be caused.
Examples of the acid used for such an acid catalyst include dichloroacetic acid, trichloroacetic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, and phenylsulfonic acid.

  Examples of the acid proliferating agent include WO95 / 29968, WO98 / 24000, JP-A-8-305262, JP-A-9-34106, JP-A-8-248561, JP-A-8-503082, and US Pat. No. 5,445. No. 9,917, JP-A-8-503081, US Pat. No. 5,534,393, US Pat. No. 5,395,736, US Pat. No. 5,741,630, US Pat. No. 5,334,489 , U.S. Patent No. 5,582,956, U.S. Patent No. 5,578,424, U.S. Patent No. 5,453,345, U.S. Patent No. 5,445,917, European Patent No. 665,960, EP 757,628, EP 665,961, U.S. Pat. No. 5,667,943, JP-A-10-1598, etc. It is possible to have.

  The amount of the acid proliferation agent added to the recording layer is 0.01 to 20% by mass, preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass in terms of solid content. Range. When the amount of the acid proliferating agent is within the above range, the effect of adding the acid proliferating agent is sufficiently obtained, the sensitivity is improved, the decrease in the film strength of the image area is suppressed, and the excellent film resulting from the specific polyurethane Strength is maintained.

(Other additives)
In forming the recording layer and the recording layer, in addition to the above essential components, various additives can be further added as necessary as long as the effects of the present invention are not impaired.

(Development accelerator)
For the purpose of improving sensitivity, acid anhydrides, phenols, and organic acids may be added to the recording layer.
As the acid anhydrides, cyclic acid anhydrides are preferable. Specific examples of the cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, and hexahydro anhydride described in US Pat. No. 4,115,128. Phthalic acid, 3,6-endooxytetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. Examples of acyclic acid anhydrides include acetic anhydride.
Examples of phenols include bisphenol A, 2,2′-bishydroxysulfone, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4- Examples include hydroxybenzophenone, 4,4 ′, 4 ″ -trihydroxytriphenylmethane, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane. .
Examples of the organic acids are described in JP-A-60-88942, JP-A-2-96755, and the like. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, Ethyl sulfuric acid, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene Examples include -1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like.
The proportion of the acid anhydride, phenols and organic acids in the total solid content of the recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, and 0.1 to 10% by mass. % Is particularly preferred.

(Other surfactants)
In addition to the above, in addition to the above, JP-A-62-170950, JP-A-11-288093, JP-A-2003-2003 are used for the recording layer in order to improve the coating properties and to expand the stability of the processing with respect to the developing conditions. A fluorine-containing monomer copolymer as described in JP-A-57820 can be added.
The ratio of the other surfactant to the total solid content of the recording layer is preferably 0.01 to 15% by mass, more preferably 0.01 to 5% by mass, and still more preferably 0.05 to 2.0% by mass. .

(Bake-out agent / colorant)
A print-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added to the recording layer.
Examples of the printing-out agent and the colorant are described in detail in paragraph numbers [0122] to [0123] of JP-A-2009-229917, and the compounds described therein can be applied to the present invention.
These dyes are preferably added at a rate of 0.01 to 10% by mass, more preferably at a rate of 0.1 to 3% by mass, based on the total solid content of the recording layer.

(Plasticizer)
A plasticizer may be added to the recording layer in order to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.
These plasticizers are preferably added at a rate of 0.5 to 10% by mass, more preferably 1.0 to 5% by mass, based on the total solid content of the recording layer.

(Wax agent)
For the purpose of imparting scratch resistance, a compound that lowers the static friction coefficient of the surface can also be added to the recording layer. Specifically, as described in US Pat. No. 6,117,913, JP-A No. 2003-149799, JP-A No. 2003-302750, or JP-A No. 2004-12770, A compound having an ester of a long-chain alkyl carboxylic acid can be exemplified.
The addition amount is preferably 0.1 to 10% by mass and more preferably 0.5 to 5% by mass in the recording layer.

<Formation of recording layer>
The recording layer in the lithographic printing plate precursor according to the invention can be usually formed by dissolving the above components in a solvent and coating the solution on a suitable support.
Solvents used here 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 Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited to. These solvents are used alone or in combination.

The coating amount of the recording layer, preferably in the range of 0.6~4.0g / ^{m 2,} more preferably in the range of 0.7 to 2.5 g / ^{m 2.} When it is 0.6 g / m ² or more, printing durability is excellent, and when it is 4.0 g / m ² or less, image reproducibility and sensitivity are excellent.

<Support>
As the support used in the lithographic printing plate precursor according to the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate having particularly good dimensional stability and relatively low cost is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less.
Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and particularly preferably 0.2 to 0.3 mm. preferable.

Such an aluminum plate may be subjected to a surface treatment such as a roughening treatment or an anodizing treatment as necessary. As for the surface treatment of the aluminum support, for example, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution, or the like, as described in detail in [0167] to [0169] of JP2009-175195A, surface The surface roughening treatment, anodizing treatment, and the like are appropriately performed.
The anodized aluminum surface is subjected to a hydrophilic treatment as necessary.
Examples of the hydrophilization treatment include an alkali metal silicate (for example, sodium silicate aqueous solution) method, a method of treating with potassium zirconate fluoride or polyvinylphosphonic acid as disclosed in [0169] of 2009-175195. Used.

<Undercoat layer>
In the present invention, an undercoat layer can be provided between the support and the recording layer as necessary.
As an undercoat layer component, various organic compounds are used. For example, phosphonic acids having amino groups such as carboxymethylcellulose and dextrin, organic phosphonic acids, organic phosphoric acids, organic phosphinic acids, amino acids, and hydroxy groups. Preferred examples thereof include hydrochlorides of amines and the like. These undercoat layer components may be used singly or in combination of two or more. Details of the compounds used for the undercoat layer and the method for forming the undercoat layer are described in paragraphs [0171] to [0172] of JP2009-175195A, and these descriptions are also applied to the present invention. The
The coverage of the organic undercoat layer is preferably 2 to 200 mg / ^{m 2,} and more preferably 5 to 100 mg / ^{m 2.} When the coating amount is in the above range, sufficient printing durability can be obtained.

<Back coat layer>
A back coat layer is provided on the back surface of the support of the lithographic printing plate precursor according to the invention, if necessary. Such a back coat layer comprises a metal oxide obtained by hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174. A coating layer is preferably used. Among these coating layers, silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ are available at a low price. The coating layer of the metal oxide obtained therefrom is particularly preferable because of its excellent developer resistance.
The lithographic printing plate precursor produced as described above is imagewise exposed and then developed.

<Plate making method of lithographic printing plate>
The lithographic printing plate production method of the present invention comprises an exposure step of exposing the infrared sensitive positive lithographic printing plate precursor of the present invention imagewise with infrared rays, and a pH of 11.0 to 13.5 (preferably 12.0 to 13.5, more preferably 12.5 to 13.5), and a development step of developing using an alkaline aqueous solution in this order.
According to the method for producing a lithographic printing plate of the present invention, the shrinkage is improved, and the obtained lithographic printing plate is free from the occurrence of stains due to the residual film in the non-image area, and the strength and durability of the image area. Excellent.
Hereafter, each process of the plate making method of this invention is demonstrated in detail.

<Exposure process>
The plate making method of the lithographic printing plate of the present invention includes an exposure step of exposing the infrared sensitive positive lithographic printing plate precursor of the present invention imagewise.
The actinic ray light source used for image exposure of the lithographic printing plate precursor according to the invention is preferably a light source having an emission wavelength in the near infrared to infrared region, and more preferably a solid laser or a semiconductor laser. Among them, in the present invention, it is particularly preferable that the image exposure is performed by a solid laser or a semiconductor laser that emits infrared rays having a wavelength of 750 to 1,400 nm.
The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec.
The energy applied to the planographic printing plate precursor is preferably 10 to 300 mJ / cm ² . When it is in the above range, curing can proceed sufficiently, laser ablation can be suppressed, and damage to the image can be prevented.

  The exposure in the present invention can be performed by overlapping the light beams of the light sources. Overlap means that the sub-scanning pitch width is smaller than the beam diameter. The overlap can be expressed quantitatively by FWHM / sub-scanning pitch width (overlap coefficient), for example, when the beam diameter is expressed by the full width at half maximum (FWHM) of the beam intensity. In the present invention, the overlap coefficient is preferably 0.1 or more.

  The scanning method of the light source of the exposure apparatus that can be used in the present invention is not particularly limited, and a cylindrical outer surface scanning method, a cylindrical inner surface scanning method, a planar scanning method, and the like can be used. The channel of the light source may be a single channel or a multi-channel, but in the case of a cylindrical outer surface system, a multi-channel is preferably used.

<Development process>
-Developer The lithographic printing plate making method of the present invention includes a developing step of developing using an aqueous alkaline solution. The alkaline aqueous solution (hereinafter also referred to as “developer”) used in the development step has a pH of 11.0 to 13.5 (preferably 12.0 to 13.5, more preferably 12.5 to 13.5). This is an alkaline aqueous solution. In addition, pH here is defined by the value measured by F-51 (brand name) by HORIBA in room temperature (20 degreeC).

In the present invention, even when a developer having a high pH is used, since the specific surfactant is combined with a specific polymer compound and applied to the photosensitive layer, high stability processability can be realized.
More specifically, the automatic processor (automatic machine) controls the alkali concentration by the electric conductivity, but if the alkali concentration is kept constant, the surfactant concentration essential for developing the polyurethane binder gradually increases. It will increase / decrease. That is, the stability of the development process is lacking.
On the other hand, in the present invention, a surfactant is charged in the image recording layer of the lithographic printing plate precursor in advance, and the surfactant concentration is kept constant from the beginning even if the developer is managed only with an alkali concentration. Has the advantage of being

  Examples of the alkaline component of the developer include lithium, sodium, and potassium, and sodium is particularly preferable. These carbonates can be used. These may be used alone or in combination of two or more.

The developer preferably contains a surfactant, and more preferably contains at least an anionic surfactant or an amphoteric surfactant. Surfactant contributes to the improvement of processability. The surfactant is preferably the same as the surfactant contained in the image recording layer of the lithographic printing plate precursor. With such a combination, the surfactant in the image recording layer and the surfactant in the developer interact with each other, contributing to the realization of better developability and stability.
As the surfactant used in the developer, any of anionic, nonionic, cationic and amphoteric surfactants can be used. As described above, anionic and amphoteric (betaine) These surfactants are preferred.
The anionic surfactant used in the developer of the present invention is not particularly limited, but fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts, dialkylsulfosuccinic acid salts, linear alkylbenzenesulfonic acid salts. Branched alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkyl diphenyl ether (di) sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine Sodium, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, sulfate esters of fatty acid alkyl esters, alkyl sulfates Ester salts, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styrylphenyl ether sulfates, alkyl phosphate esters, polyoxyethylene alkyl ether phosphates Salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene-maleic anhydride copolymer partial saponification products, olefin-maleic anhydride copolymer partial saponification products, naphthalene sulfonate formalin condensates, etc. Can be mentioned. Among these, alkylbenzene sulfonates, alkyl naphthalene sulfonates, and alkyl diphenyl ether (di) sulfonates are particularly preferably used.

The nonionic surfactant used in the developer of the present invention is not particularly limited, but is a polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide adduct, phenol ethylene oxide adduct. , Naphthol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide addition Dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) Id) block copolymer, fatty acid ester of polyhydric alcohol type glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol, fatty acid amide of alkanolamines, etc. Is mentioned. Among these, those having an aromatic ring and an ethylene oxide chain are preferable, and an alkyl-substituted or unsubstituted phenol ethylene oxide adduct or an alkyl-substituted or unsubstituted naphthol ethylene oxide adduct is more preferable.
The amphoteric surfactant used in the developer of the present invention is not particularly limited, but is alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium. Examples include betaine and N-tetradecyl-N, N-betaine type.

As the surfactant used in the developer, an anionic surfactant and an amphoteric surfactant are preferable, and an anionic surfactant containing a sulfonic acid or a sulfonate is particularly preferable.
Surfactants can be used alone or in combination.
The content of the surfactant in the developer is preferably from 0.01 to 10% by mass, and more preferably from 0.01 to 5% by mass.

In order to keep the developer at a suitable pH, the presence of carbonate ions and hydrogen carbonate ions as buffering agents can suppress pH fluctuations even when the developer is used for a long period of time, and developability due to pH fluctuations. Reduction, development debris generation and the like can be suppressed. In order to allow carbonate ions and hydrogen carbonate ions to be present in the developer, carbonate and hydrogen carbonate may be added to the developer, or by adjusting the pH after adding carbonate or bicarbonate, Ions and bicarbonate ions may be generated. 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. These may be used alone or in combination of two or more.
The pH of the developer is not particularly limited as long as it can be developed, but it is preferably in the range of pH 8.5 to 10.8.

  The total amount of carbonate and bicarbonate is preferably 0.3 to 20% by mass, more preferably 0.5 to 10% by mass, and particularly preferably 1 to 5% by mass with respect to the total mass of the developer. When the total amount is 0.3% by mass or more, developability and processing capacity do not decrease, and when it is 20% by mass or less, it becomes difficult to form precipitates and crystals. It becomes difficult to gel and does not interfere with waste liquid treatment.

  In addition, organic alkali agents, wetting agents, preservatives, chelate compounds, antifoaming agents, organic acids, organic solvents, polar solvents, inorganic acids, inorganic salts, etc. are applied as appropriate to this type of developer. May be.

-Development processing Although there will be no restriction | limiting in particular if the temperature of image development is developable, It is preferable that it is 60 degrees C or less, and it is more preferable that it is 15-40 degreeC. In the development processing using an automatic developing machine, the developing solution may be fatigued depending on the processing amount. Therefore, the processing capability may be restored using a replenishing solution or a fresh developing solution. An example of development and post-development processing is a method in which alkali development is performed, alkali is removed in a post-water washing step, gumming is performed in a gumming step, and drying is performed in a drying step. As another example, a method in which pre-water washing, development and gumming are simultaneously performed by using an aqueous solution containing carbonate ions, hydrogen carbonate ions and a surfactant can be preferably exemplified. Therefore, the pre-water washing step is not particularly required, and it is preferable to perform the drying step after performing pre-water washing, development and gumming in one bath only by using one liquid. After development, it is preferable to dry after removing excess developer using a squeeze roller or the like.

  The development process can be preferably carried out by an automatic processor equipped with a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs a rubbing process while conveying a lithographic printing plate precursor after image exposure, or a cylinder Examples thereof include an automatic processor described in US Pat. Nos. 5,148,746, 5,568,768 and British Patent 2,297,719, which rub the lithographic printing plate precursor after image exposure set above while rotating a cylinder. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

It is preferable to provide a drying step continuously or discontinuously after the development step. Drying is performed by hot air, infrared rays, far infrared rays, or the like.
As an automatic processor suitably used in the method for preparing a lithographic printing plate according to the present invention, an apparatus having a developing unit and a drying unit is used, and development and gumming are performed on a lithographic printing plate precursor in a developing tank. And then dried in a drying section to obtain a lithographic printing plate.

Further, for the purpose of improving printing durability, the developed printing plate can be heated under very strong conditions. The heating temperature is usually in the range of 200 to 500 ° C. If the temperature is low, sufficient image strengthening action cannot be obtained, and if it is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.
The lithographic printing plate obtained in this way is applied to an offset printing machine and is suitably used for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to them.

[Synthesis Example 1]
Polymer A was prepared using the following procedure:
BF-03 (50 g) was added to a reaction vessel equipped with a water-cooled condenser, a dropping funnel and a thermometer and containing DMSO (200 g). With continuous stirring, the mixture was heated at 80 ° C. for 30 minutes until the mixture became a clear solution. The temperature was then adjusted to 60 ° C. and MSA (2.7 g) in DMSO (50 g) was added. Over 15 minutes, a solution of butyraldehyde (10.4 g) was added to the reaction mixture and the reaction mixture was kept at 55-60 ° C. for 1 hour. Next, 2-hydroxybenzaldehyde (salicylic aldehyde, 39 g) in DMSO (100 g) was added to the reaction mixture. The reaction mixture was then diluted with anisole (350 g) and vacuum distillation was started. The anisole: water azeotrope was distilled from the reaction mixture (remaining water in solution less than 0.1%). The reaction mixture was cooled to room temperature, neutralized with TEA (8 g) dissolved in DMSO (30 g) and then blended with 6 kg of water. The resulting polymer was washed with water, filtered, and dried in vacuum at 50 ° C. for 24 hours to obtain 80 g of dried polymer A.

• BF-03 is available from Chang Chun Petrochemical Co. , Ltd., Ltd. Poly (vinyl alcohol) obtained from (Taiwan), 98% hydrolysis (Mw = 15,000).
MSA represents methanol sulfonic acid (99%).
DMSO represents dimethyl sulfoxide.
TEA represents triethanolamine.

[Example 1, Comparative Example 1]
The photosensitive composition of an Example and a comparative example was manufactured as follows.
――――――――――――――――――――――――――――――――――――
Polymer A 7.22g
Crystal Violet 0.20g
S0094IR dye 0.16 g
Surfactant described in Table 1 Amount described in Table 1 PM (1-methoxy-2-propanol) 91.8 g
――――――――――――――――――――――――――――――――――――

  Each formulation is filtered and applied in an ordinary manner to an aluminum substrate that has been electrochemically roughened and anodized and subjected to treatment with an aqueous solution of poly (vinylphosphonic acid), The resulting imageable layer coating was dried at 105 ° C. for 2.5 hours in a “Unigraph Quartz” oven from Glunz & Jensen. The dry coverage of each imageable layer was about 1.5 g / m2.

  The obtained lithographic printing plate precursor was evaluated as follows. The results are shown in Table 1.

<Evaluation of running residue>
In the automatic developing machine in which the development starting solution conductivity value of 40 mS / cm and the equilibrium conductivity value of 45 mS / cm are input to the control unit of the automatic developing machine, the running plate is averaged at 50 sheets per day for one month. Processed. During the exposure, the entire surface was exposed with a Trendsetter (trade name) manufactured by Creo at a beam intensity of 9 w and a drum rotation speed of 150 rpm.
One month later, the developer was removed from the developer tank and the situation was visually observed. As a result, no development residue was found.
AA: A state in which the developer is removed from the developer tank and visually confirmed to have no or almost no development residue B: A level in which developer residue is removed from the developer tank and visually confirmed to allow development residue to be easily observed C: Development tank The level at which development residue adheres to the plate when the plate is passed without removing the developer from the plate

<Evaluation of film reduction>
Evaluation of film reduction due to development of image area The unexposed lithographic printing plate precursor was then diluted with Fuji Film's automatic processor LP-940H with Fuji Film's developer DT-2 (1: 8). And a finisher FG-1 (diluted 1: 1) manufactured by Fuji Film Co., Ltd., and developed at a developer temperature of 32 ° C. and a development time of 12 seconds. The electric conductivity of the developer at this time was 43 mS / cm.
The optical density of the photosensitive layer before and after development was measured, and the relative density when the density obtained by subtracting the density of the aluminum support alone from the density before development was taken as 100% was expressed as the reduction in the developed film.
A: 90% or more A: 85% or more and less than 90% B: 80% or more and less than 85% C: Less than 80%

<Evaluation of printing durability>
A test pattern was drawn on the lithographic printing plate precursor in the form of an image with a Trend setter (trade name) manufactured by Creo at a beam intensity of 9 w and a drum rotation speed of 150 rpm. Thereafter, a PS processor LP940H (trade name) manufactured by Fuji Film Co., Ltd. charged with developer DT-2 (trade name) manufactured by Fuji Film Co., Ltd. (diluted to a conductivity of 43 mS / cm) was used. Development was performed at a development temperature of 30 ° C. and a development time of 12 seconds. This was continuously printed using a printing press Lislon (trade name) manufactured by Komori Corporation. At this time, the number of sheets that can be printed while maintaining a sufficient ink density was measured visually to evaluate the printing durability. The printing durability was shown as a relative value when the printing durability of Comparative Example 1 was 1.0. As the test pattern, a solid image (entire image portion) of 2 cm × 2 cm was used. According to the visual evaluation of the printed matter, the number of scumming or missing in the printing portion was determined as the number of finished prints. At this time, “1.0” was 40,000 sheets.
AA: 90% or more A: 85% or more and less than 90% B: 80% or more and less than 85% C: less than 80% <Evaluation of waste liquid concentration aptitude>
Using the waste liquid reduction device XR-2000 manufactured by Fuji Film Graphic Systems Co., Ltd., and the AF-A manufactured by Fuji Film Co., Ltd. diluted to 3% with water. Used to concentrate.
It evaluated from the concentration rate and the BOD value of distilled regenerated water.
AA: Concentration rate of 4 times or more and BOD value less than 300 mg / L A: Concentration rate of 3 times or more and less than 4 times and BOD value of less than 300 mg / L B: Concentration rate of 2 times or more and less than 3 times and BOD value Less than 300 mg / L C: Concentration rate 1 to 2 times and BOD value less than 300 mg / L D: Concentration rate 1 to 2 times and BOD value 300 mg / L or more

(Developer)
・ D-Sorbit 2.5% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 96.15% by mass

＊１：界面活性剤を含む記録層の固形分総和に対する含有率である。以下の表についても同じ。
・ソフタゾリンＬＰＢ−Ｒ：商品名、アミドベタイン型の両性界面活性剤、
川研ファインケミカル株式会社製
・ソフタゾリンＬＡＯ：商品名、アミドアミンオキシド型両性界面活性剤、
川研ファインケミカル株式会社製
・ニューコールＢ４ＳＮ：商品名、アニオエン性界面活性剤、
日本乳化剤株式会社製
Ｒ−Ｏ−（ＣＨ_２ＣＨ_２Ｏ）ｎ−ＳＯ_３Ｎａ （Ｒ：アリール基、ｎ：整数）
・ペレックスＮＢＬ：商品名、アニオン性界面活性剤、花王株式会社製
アルキルナフタレンスルホン酸ナトリウム、
＊２：ｃから始まる番号の試験例は比較例を意味する。以下の実施例・比較例についても同様である。

* 1: Content relative to the total solid content of the recording layer containing the surfactant. The same applies to the following tables.
Softazoline LPB-R: trade name, amidobetaine type amphoteric surfactant,
Kawaken Fine Chemical Co., Ltd., Softazoline LAO: trade name, amidoamine oxide amphoteric surfactant,
Kawaken Fine Chemical Co., Ltd. New Coal B4SN: trade name, anionic surfactant,
_R-O- manufactured by Nippon Nyukazai Co., Ltd. _{(CH 2 CH 2 O) n} -SO 3 Na (R: an aryl group, n: integer)
Pelex NBL: trade name, anionic surfactant, sodium alkylnaphthalene sulfonate manufactured by Kao Corporation,
* 2: Test examples with numbers starting with c mean comparative examples. The same applies to the following examples and comparative examples.

[Example 2, Comparative Example 2]
(Production of support)
The support body was produced by processing through the process shown below using a JIS-A-1050 aluminum plate with a thickness of 0.3 mm.

(A) Mechanical roughening treatment
While a suspension of a polishing agent (silica sand) having a specific gravity of 1.12 and water was supplied to the surface of the aluminum plate as a polishing slurry, mechanical surface roughening was performed with a rotating roller-like nylon brush. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was sprayed with an aqueous NaOH solution at a temperature of 70 ° C. (concentration 26 mass%, aluminum ion concentration 6.5 mass%) to carry out an etching treatment, and the aluminum plate was 6 g / m. ² dissolved. Thereafter, washing with water was performed using well water.

(C) Desmut treatment
A desmut treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid having a nitric acid concentration of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.5 g / liter aqueous solution (aluminum ion 5 g / liter) at a temperature of 50 ° C. The AC power supply waveform has an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero, a DUTY ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type. The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Thereafter, washing with water was performed using well water.

(E) Alkaline etching treatment The aluminum plate was sprayed at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C., and the aluminum plate was dissolved at 0.20 g / m ^2. The smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was used was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(F) Desmut treatment Desmut treatment was performed by spraying with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water using well water. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Thereafter, washing with water was performed using well water.

(H) Alkaline etching treatment The aluminum plate was sprayed at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C., and the aluminum plate was dissolved at 0.10 g / m 2. Thus, the smut component mainly composed of aluminum hydroxide generated during the electrochemical surface roughening treatment was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.
(I) Desmut treatment A desmut treatment by spraying was performed with a 25% by mass aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by mass of aluminum ions), and then water washing by spraying was performed using well water.

(J) Anodizing treatment As the electrolytic solution, sulfuric acid was used. All electrolytes had a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), and the temperature was 43 ° C. Thereafter, washing with water was performed using well water.
Both current densities were about 30 A / dm ² . The final oxide film amount was 2.7 g / m ² .

Each process of said (a)-(j) was performed in order, and the support body was produced.
The support obtained as described above was subsequently subjected to the following hydrophilic treatment and undercoating treatment.

(K) Alkali metal silicate treatment An alkali metal silica was obtained by immersing the aluminum support obtained by anodizing treatment in a treatment layer of a 1 mass% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C for 10 seconds. Acid salt treatment (silicate treatment) was performed. Then, the water washing by the spray using well water was performed. The amount of silicate adhering at that time was 3.6 mg / m ² .

[Undercoating]
On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds to form an undercoat layer.
The coating amount after drying was 15 mg / m ² .

(Coating solution for undercoat layer)
・ The following polymer compound (the following formula (I)) 0.3 g
・ Methanol 100g
・ Water 1g

(Formation of recording layer)
Next, the lower layer coating solution A having the following composition was applied to the support with the undercoat layer obtained above with a wire bar, and then dried in a drying oven at 140 ° C. for 50 seconds to obtain a coating amount of 0.85 g. / M ² .
The upper layer coating liquid B having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 140 ° C. for 60 seconds to obtain positive lithographic printing plate precursors of Examples and Comparative Examples with a total coating amount of 1.1 g / m ² .

<Coating liquid A for lower layer>
・ Polymer A 2.13g
-Surfactant shown in Table 2 (Amount listed in Table 2)
・ The cyanine dye A 0.134 g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.19g
・ 0.008 g of p-toluenesulfonic acid
2-methoxy-4- (N-phenylamino)
Benzenediazonium hexafluorophosphate 0.032 g
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.023g
・ Γ-butyrolactone 13.16 g
・ Methyl ethyl ketone 25.39g
・ 1-methoxy-2-propanol 12.95 g

<Upper layer coating solution B>
M-cresol / p-cresol (60/40) novolak (weight average molecular weight 4000) 0.341 g
・ The cyanine dye A 0.019 g
・ The following structural polymer 1 / MEK 30% solution (the following structure) 0.14 g
・ Quaternary ammonium salt (the following structure) 0.004g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.004g
-Fluorosurfactant (Megafac F-781, manufactured by Dainippon Ink & Chemicals, Inc.) 0.001g
・ Methyl ethyl ketone 2.63g
・ 1-methoxy-2-propanol 5.27g

  The obtained lithographic printing plate precursor was evaluated as follows. The results are shown in Table 2.

(Developer)
・ D-Sorbit 2.5% by mass
-Softazolin LAO (30% solution) 12% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 84.15 mass%

＊１、＊２は表１と同義である。

* 1 and * 2 are synonymous with Table 1.

[Example 3, Comparative Example 3]
Except for changing the acetal resin to be used from the polymer A to the polymers B to I, the evaluation was made in the same manner as in Example 2 with respect to running debris, film reduction, and printing durability. The results are shown in Table 3.

  Details of the polymers B to I are as follows.

Polymer B: (a / b / c / d / e = 36/37/2/25/0; weight average molecular weight: 16000)
R ¹ = n-butyl group R ² = 4-hydroxybenzyl group / polymer C: (a / b / c / d / e = 12/49/17/22/0; weight average molecular weight: 14000)
R ¹ = n-butyl group R ² = 3-hydroxybenzyl group / polymer D: (a / b / c / d / e = 30/41/2/20/9; weight average molecular weight: 18000)
R ¹ = n-butyl group R ² = 2-hydroxybenzyl group R ⁶ = glyoxylic acid group
Polymer E: (a / b / c / d / e = 21/43/2/24/10; weight average molecular weight: 16000)
R ¹ = n-butyl group R ² = 3-hydroxybenzyl group R ⁶ = propargyl group / polymer F: (a / b / c / d / e = 38/42/2/18/0; weight average molecular weight: 18000 )
R ¹ = n-butyl group R ² = 2-hydroxybenzyl group / polymer G: (a / b / c / d / e = 25/38/12/26/0; weight average molecular weight: 16000)
R ¹ = n-butyl group R ² = 4-hydroxybenzyl group / polymer H: (a / b / c / d / e = 16/10/12/44/18; weight average molecular weight: 18000)
R ¹ = n-isobarrel group R ² = 2-hydroxybenzyl group R ⁶ = 4-formylphenoxyacetic acid group / polymer I: (a / b / c / d / e = 14/44/2/40/0; weight (Average molecular weight: 16000)
R ¹ = n-butyl group R ² = 3,5-dibromo-4-hydroxybenzyl group

  The obtained lithographic printing plate precursor was evaluated as follows. The results are shown in Table 3.

(Developer)
・ D-Sorbit 2.5% by mass
-Softazolin LAO (30% solution) 12% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 84.15 mass%

＊１、＊２は表１と同義である。

* 1 and * 2 are synonymous with Table 1.

[Example 4, Comparative Example 4]
(Formation of recording layer)
Next, the lower layer coating solution a having the following composition was applied to the support with the undercoat layer obtained in the above-described example with a wire bar, and then dried in a drying oven at 140 ° C. for 50 seconds to reduce the coating amount to 0. It was .85G / ^{M 2.}
An upper layer coating solution b 1 having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 140 ° C. for 60 seconds to obtain positive lithographic printing plate precursors of Examples and Comparative Examples with a total coating amount of 1.1 G / M ² .

<Coating liquid A for lower layer>
・ Polymer A 2.13g
-Surfactant shown in Table 4 (Amount listed in Table 4)
・ The cyanine dye A 0.134 g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.19g
・ 0.008 g of p-toluenesulfonic acid
2-methoxy-4- (N-phenylamino)
Benzenediazonium hexafluorophosphate 0.032 g
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.023g
・ Γ-butyrolactone 13.16 g
・ Methyl ethyl ketone 25.39g
・ 1-methoxy-2-propanol 12.95 g

<Upper layer coating solution B>
M-cresol / p-cresol (60/40) novolak (weight average molecular weight 4000) 0.341 g
-Surfactant shown in Table 4 (Amount listed in Table 4)
・ The cyanine dye A 0.019 g
・ Polymer 1 / MEK 30% solution (the above structure) 0.14 g
・ Quaternary ammonium salt (the above structure) 0.004g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.004g
-Fluorosurfactant (Megafac F-781, manufactured by Dainippon Ink & Chemicals, Inc.) 0.001g
・ Methyl ethyl ketone 2.63g
・ 1-methoxy-2-propanol 5.27g

  The obtained lithographic printing plate precursor was evaluated as follows. The results are shown in Table 4.

(Developer)
・ D-Sorbit 2.5% by mass
-Softazolin lao (30% solution) 12% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 84.15 mass%

＊１は表１と同義である。

* 1 is synonymous with Table 1.

[Example 5, Comparative Example 5]
(substrate)
The surface of the aluminum sheet was subjected to an electrolytic surface roughening treatment with 2% hydrochloric acid. The average roughness Ra was 0.5 μm. Furthermore, anodization treatment was performed in a 20% aqueous sulfuric acid solution, and the oxide film amount was set to 2.7 g / m ² . Then, it was immersed in a sodium silicate 2.5 wt% aqueous solution at 70 ° C. for 30 minutes, washed with water and dried.

(Image recording layer)
The lower layer coating solution 1 shown below was applied to the substrate obtained as described above with a bar coater so that the coating weight was 1.5 g / m ² , dried at 130 ° C. for 40 seconds, and then up to 35 ° C. Cooled down. Furthermore, the coating solution of the upper layer shown below was applied with a bar coater so that the coating weight was 0.5 g / m 2, dried at 135 ° C. for 40 seconds, and then slowly cooled from 20 to 26 ° C. Thus, a lithographic printing plate precursor was obtained.

<Coating liquid for lower layer>
N-phenylmaleimide / methacrylic acid / methacrylamide copolymer (weight ratio 59.15.25, Mw 50000) 5.21 g
・ 0.94 g of the cyanine dye A
・ Crystal Violet 0.08g
・ BYK307 (bykchemie) 0.03g
・ Methyl ethyl ketone 61.0g
・ Propylene glycol monomethyl ether 14.0 g
・ Γ-butyrolactone 9.40 g
・ Water 9.34g

<Upper layer coating solution>
・ Polymer A 7.5g
・ Surfactants shown in Table 5 (Amounts listed in Table 5)
・ Ethyl violet 0.03g
・ Crystal Violet 0.08g
・ Fluorine surfactant (Megafac F-176, manufactured by Dainippon Ink & Chemicals, Inc.)
0.05g
・ 3-Pentanone 62.50g
・ Propylene glycol 1-monomethyl ether 2-acetate 29.92 g

  The obtained lithographic printing plate precursor was evaluated as follows. The results are shown in Table 5.

(Developer)
・ D-Sorbit 2.5% by mass
・ New Coal B4SN (60% solution) 7% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 89.15% by mass

＊１、＊２は表１と同義である。

* 1 and * 2 are synonymous with Table 1.

  As is clear from the above, the lithographic printing plate precursor of the present invention has significantly improved running debris compared to the comparative example, has sufficient performance without film reduction, and exhibits high printing durability. It was. From this result, it is understood that the lithographic printing plate precursor having a recording layer containing the amphoteric surfactant or anionic surfactant of the present invention realizes high developability as well as high printing durability.

1 Image recording layer 3 Undercoat layer 4 Support 10 Planographic printing plate precursor

Claims (10)

  An infrared-sensitive positive lithographic printing plate precursor having an image recording layer on a support having a hydrophilic surface, wherein the image recording layer comprises poly (vinyl acetal), an amphoteric surfactant, and / or Alternatively, a lithographic printing plate precursor comprising an anionic surfactant and an infrared absorber.   An infrared-sensitive positive lithographic printing plate precursor having an image recording layer in which a lower layer and an upper layer are arranged in this order on a support having a hydrophilic surface, wherein the upper layer and / or the lower layer is a poly ( The lithographic printing plate according to claim 1, wherein the vinyl acetal), the amphoteric surfactant and / or the anionic surfactant, and the infrared absorber are contained in the same layer or in separate layers. A printing plate master. The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the amphoteric surfactant is represented by any one of the following general formulas (I) to (III).

(In General Formulas (I) to (III), R ¹ represents an alkyl group having 6 to 24 carbon atoms or an alkyl group via a specific linking group. R ² and R ³ each independently has 1 to 5 carbon atoms. R ⁴ and R ⁵ each independently represents an alkyl group having 1 to 5 carbon atoms, provided that at least one of R ⁴ and R ⁵ has an acidic group or a salt thereof at the terminal, L ¹ is carbon .X which represents a linking group having 1 to 4 ^- represents a carboxylate ion, sulfonate ion, sulfate ion, phosphonate or phosphate ions). The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the anionic surfactant is represented by any one of the following formulas (IV) to (VI ) .

(In the general formula (IV) ~ (V I) , .D 1, E 1, F 1 R 6 is representative of the .L ² is a phenylene group or a single bond represents an alkyl group having 6 to 24 carbon atoms sulfonate ion Or a salt thereof, or a sulfate ion or a salt thereof, R ⁷ represents an alkyl group having 4 to 18 carbon atoms, L ³ represents a phenylene group or a naphthylene group, and R ⁸ represents a phenyl group or a naphthyl group. ⁴ represents a polyalkyleneoxy group .) The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the repeating unit of the poly (vinyl acetal) is represented by the following general formula (a).

(Where R and R ′ are independently hydrogen or an alkyl or halogen atom, and Rx is a phenol, naphthol or anthracenol group.) The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the repeating unit of the poly (vinyl acetal) is represented by the following general formula (b).

(Here, R and R ′ are independently hydrogen, an alkyl, or a halogen atom. Ry represents any of the following R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ , The resin represented by (a) is a copolymer containing one or more repeating units of different Ry.
R ₁ is an alkyl group, a cycloalkyl group, or an aryl group other than phenol or naphthol,
R ₂ has the same meaning as Rx,
R ₃ is a C 2-6 alkynyl group or phenyl group. )   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the surfactant is contained in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the poly (vinyl acetal).   A method for producing a lithographic printing plate comprising an exposure step for image exposure of an image recording layer of the lithographic printing plate precursor according to any one of claims 1 to 7 and a development step for development using an aqueous alkali solution in this order.   The method of preparing a lithographic printing plate according to claim 8, wherein the aqueous alkaline solution contains an anionic surfactant, a nonionic surfactant, or an amphoteric surfactant. The preparation of a lithographic printing plate according to claim 8, wherein the amphoteric surfactant and / or the anionic surfactant contained in the lithographic printing plate is the same as the surfactant contained in the alkaline aqueous solution. Method.

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