JP2010072389A - Original plate of planographic printing plate and manufacturing method of planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original plate of a planographic printing plate having excellent developability, sensitivity, printing durability and dot reproducibility, with less production of development scum in the developing solution at the development, and also to provide a manufacturing method of a planographic printing plate. <P>SOLUTION: The original plate of the planographic printing plate contains on a supporting member (i) a binder polymer, (ii) an ethylenically unsaturated compound, and (iii) a photosensitive layer containing a polymerization initiator. (ii) The ethylenically unsaturated compound contains a compound represented by formula (1), wherein L is a linking group of the (m+n)th valence, D is a group selected from the group consisting of the groups represented by formulae (A)-(D), m is an integer of 1 or more, and n is an integer of 2 or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a planographic printing plate precursor and a method for producing a planographic printing plate.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing uses the property that water and printing ink repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). As described above, a difference in ink adhesion is caused on the surface of a lithographic printing plate, and after ink is applied only to an image portion, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (photosensitive layer, image recording layer) is provided on a hydrophilic support has been widely used. Yes. Usually, after exposing the lithographic printing plate precursor through an original image such as a lithographic film, the portion to be the image portion of the image recording layer is left, and the other unnecessary image recording layer is made an alkaline developer or organic A lithographic printing plate is obtained by dissolving and removing with a solvent and exposing the surface of the hydrophilic support to form a non-image area.

  As described above, in the plate making process of a conventional lithographic printing plate precursor, a step of dissolving and removing an unnecessary image recording layer with a developer or the like is necessary after exposure. Treatment with a developing solution and a small amount of waste liquid are cited as problems. In particular, in recent years, disposal of waste liquid discharged with wet processing has become a major concern for the entire industry due to consideration for the global environment, and the demand for solving the above-mentioned problems has become stronger.

  On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate (CTP) technology has been attracting attention.

On the other hand, for example, Patent Document 1 proposes a developing method in which processing is performed with a developer having an alkali metal carbonate and a bicarbonate having a pH of 8.5 to 11.5 and an electrical conductivity of 3 to 30 mS / cm. ing.
Moreover, the Example of patent document 2 describes the process by the process liquid containing the water-soluble high molecular compound of pH 11.9-12.
Patent Document 3 describes treatment with a treatment liquid containing a water-soluble polymer compound having a pH of 3 to 9.

JP-A-11-65126 European Patent Application No. 1868036 Special table 2007-538279 gazette

As mentioned above, the low alkali level of the developer and the simplification of the processing process are more strongly desired than ever in terms of consideration for the global environment, space saving, and low running cost. It has become to. However, the conventional development process consists of three steps of developing with an alkaline aqueous solution having a pH of 11 or more, then pouring an alkaline agent in a washing bath, and then treating with a gum solution mainly composed of a hydrophilic resin. The automatic developing machine itself takes up a lot of space, and there are still problems in terms of environment and running cost, such as the problem of developing waste liquid, washing waste liquid, and gum waste liquid treatment.
In a lithographic printing plate precursor as described in Patent Document 1, when processing is performed with a developer whose pH has been lowered, residue derived from an ethylenically unsaturated compound is present in the developer when a large amount of development processing is performed. There is a problem that it tends to occur, and there is a problem that a halftone dot portion (small dot portion) becomes thin when printing is performed by a printing machine after exposure / development processing.
Further, in Patent Document 2, the obtained printing plate is in a state where the pH 12 alkali is still attached to the plate surface, and there is a problem in terms of safety for the operator. As the time elapses, there is a problem that the image portion is gradually dissolved to cause deterioration in printing durability and inking property.
Further, in the method for producing a lithographic printing plate as described in Patent Document 3, since the processing liquid does not contain a base component, it is necessary to make the polymer of the photosensitive layer hydrophilic so that it can be developed. There is a problem that the remarkably decreases.

  The present invention has been made in view of the above problems, and an object of the present invention is a lithographic plate which is excellent in developability, sensitivity, printing durability, and halftone dot reproducibility, and produces less development residue in the developer during development. It is to provide a method for producing a printing plate precursor and a planographic printing plate.

The above-described problems of the present invention have been solved by the means described in <1> or <5> below. It describes below with <2>-<4> and <6>-<11> which are preferable embodiments.
<1> On a support, it has a photosensitive layer containing (i) a binder polymer, (ii) an ethylenically unsaturated compound, and (iii) a polymerization initiator, and (ii) the ethylenically unsaturated compound is A lithographic printing plate precursor comprising a compound represented by the following formula (1):

（式（１）中、Ｌは（ｍ＋ｎ）価の連結基を表し、Ｄは下記式（Ａ）〜（Ｄ）で表される基よりなる群から選ばれた基を表し、ｍは１以上の整数を表し、ｎは２以上の整数を表す。）

(In formula (1), L represents a (m + n) -valent linking group, D represents a group selected from the group consisting of groups represented by the following formulas (A) to (D), and m is 1 or more. And n represents an integer of 2 or more.)

（式（Ａ）〜（Ｄ）中、Ｘ、Ｙ及びＺはそれぞれ独立に、酸素原子、硫黄原子又はＮＲ¹⁷を表し、Ｒ⁴〜Ｒ¹⁴及びＲ¹⁷はそれぞれ独立に、水素原子又は一価の有機基を表し、Ｒ¹⁵は水素原子又はメチル基を表し、Ｒ¹⁶は一価の置換基を表し、ｋは０〜４の整数を表す。）
＜２＞前記式（１）におけるＤが、前記式（Ａ）で表される基である上記＜１＞に記載の平版印刷版原版、
＜３＞前記式（１）におけるＬが、エーテル結合、エステル結合、ウレタン結合、チオウレタン結合、及び／又は、ウレア結合を有する基である上記＜１＞又は＜２＞に記載の平版印刷版原版、
＜４＞前記式（１）におけるＬが、ウレタン結合、チオウレタン結合、及び／又は、ウレア結合を有する基である上記＜１＞〜＜３＞のいずれか１つに記載の平版印刷版原版、
＜５＞上記＜１＞〜＜４＞のいずれか１つに記載の平版印刷版原版を画像露光する露光工程、及び、緩衝能を有する現像液の存在下で非露光部の感光層を除去する現像工程を含むことを特徴とする平版印刷版の製造方法、
＜６＞前記緩衝能を有する現像液のｐＨが、７．５〜１１．０である上記＜５＞に記載の平版印刷版の製造方法、
＜７＞前記緩衝能を有する現像液が、（ａ）炭酸イオン−炭酸水素イオンの組み合わせ、（ｂ）ホウ酸イオン、又は、（ｃ）水溶性のアミン化合物−そのアミン化合物のイオンの組み合わせを含む現像液である上記＜５＞又は＜６＞に記載の平版印刷版の製造方法、
＜８＞前記緩衝能を有する現像液が、（ａ）炭酸イオン−炭酸水素イオンの組み合わせを含む現像液である上記＜５＞〜＜７＞のいずれか１つに記載の平版印刷版の製造方法、
＜９＞前記緩衝能を有する現像液が、水溶性高分子化合物を含む上記＜５＞〜＜８＞のいずれか１つに記載の平版印刷版の製造方法、
＜１０＞前記現像工程が、非露光部の感光層の除去及びガム引き処理を１液で行う工程である上記＜５＞〜＜９＞のいずれか１つに記載の平版印刷版の製造方法、
＜１１＞前記現像工程の前及び後のいずれにも水洗工程を施さない上記＜５＞〜＜１１＞のいずれか１つに記載の平版印刷版の製造方法。

(In the formulas (A) to (D), X, Y and Z each independently represent an oxygen atom, a sulfur atom or NR ¹⁷ , and R ^{4 to} R ¹⁴ and R ¹⁷ each independently represent a hydrogen atom or a monovalent group. R ¹⁵ represents a hydrogen atom or a methyl group, R ¹⁶ represents a monovalent substituent, and k represents an integer of 0 to 4.)
<2> The lithographic printing plate precursor as described in <1> above, wherein D in the formula (1) is a group represented by the formula (A),
<3> The lithographic printing plate according to <1> or <2>, wherein L in the formula (1) is a group having an ether bond, an ester bond, a urethane bond, a thiourethane bond, and / or a urea bond. Original,
<4> The lithographic printing plate precursor as described in any one of <1> to <3> above, wherein L in the formula (1) is a group having a urethane bond, a thiourethane bond, and / or a urea bond. ,
<5> An exposure process for image exposure of the lithographic printing plate precursor as described in any one of <1> to <4> above, and removal of a photosensitive layer in an unexposed area in the presence of a developer having a buffering capacity A process for producing a lithographic printing plate comprising a developing step,
<6> The method for producing a lithographic printing plate according to <5>, wherein the pH of the developer having a buffering capacity is 7.5 to 11.0,
<7> The developer having the buffering capacity is a combination of (a) a carbonate ion-bicarbonate ion, (b) a borate ion, or (c) a water-soluble amine compound-an ion of the amine compound. The method for producing a lithographic printing plate according to <5> or <6> above, which is a developer containing
<8> Production of a lithographic printing plate according to any one of the above <5> to <7>, wherein the developer having a buffer capacity is a developer containing a combination of (a) carbonate ion and hydrogen carbonate ion Method,
<9> The method for producing a lithographic printing plate according to any one of the above <5> to <8>, wherein the developer having a buffering capacity contains a water-soluble polymer compound,
<10> The method for producing a lithographic printing plate according to any one of <5> to <9>, wherein the development step is a step of removing the photosensitive layer in the non-exposed area and performing a gumming treatment with one solution. ,
<11> The method for producing a lithographic printing plate according to any one of <5> to <11>, wherein the water washing step is not performed before and after the development step.

  According to the present invention, there are provided a lithographic printing plate precursor excellent in developability, sensitivity, printing durability and halftone dot reproducibility, and generating less development residue in a developing solution during development, and a method for producing a lithographic printing plate. I was able to.

  Hereinafter, the planographic printing plate precursor and the method for producing the planographic printing plate of the present invention will be described in detail.

[Lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention has, on a support, a photosensitive layer containing (i) a binder polymer, (ii) an ethylenically unsaturated compound, and (iii) a polymerization initiator, The ethylenically unsaturated compound contains a compound represented by the following formula (1).

（式（１）中、Ｌは（ｍ＋ｎ）価の連結基を表し、Ｄは下記式（Ａ）〜（Ｄ）で表される基よりなる群から選ばれた基を表し、ｍは１以上の整数を表し、ｎは２以上の整数を表す。）

(In formula (1), L represents a (m + n) -valent linking group, D represents a group selected from the group consisting of groups represented by the following formulas (A) to (D), and m is 1 or more. And n represents an integer of 2 or more.)

（式（Ａ）〜（Ｄ）中、Ｘ、Ｙ及びＺはそれぞれ独立に、酸素原子、硫黄原子又はＮＲ¹⁷を表し、Ｒ⁴〜Ｒ¹⁴及びＲ¹⁷はそれぞれ独立に、水素原子又は一価の有機基を表し、Ｒ¹⁵は水素原子又はメチル基を表し、Ｒ¹⁶は一価の置換基を表し、ｋは０〜４の整数を表す。）

(In the formulas (A) to (D), X, Y and Z each independently represent an oxygen atom, a sulfur atom or NR ¹⁷ , and R ^{4 to} R ¹⁴ and R ¹⁷ each independently represent a hydrogen atom or a monovalent group. R ¹⁵ represents a hydrogen atom or a methyl group, R ¹⁶ represents a monovalent substituent, and k represents an integer of 0 to 4.)

The lithographic printing plate precursor according to the invention is a negative lithographic printing plate precursor and can be suitably developed with a developer having a buffering capacity.
The lithographic printing plate precursor according to the present invention has a photosensitive layer having the above-described structure, so that it is excellent in developability, sensitivity, printing durability, and halftone dot reproducibility, and the generation of development residue in the developer during development may be reduced. it can.
Although the mechanism of action in the planographic printing plate precursor of the present invention is not clear, the following is presumed.
When the pH of the developer is lowered, the developer permeability into the printing plate is lowered. In the high pH region, the degree of curing that has been developed at the time of development is low, and the side edge portion that is not firmly cured remains difficult to be developed in the low pH region. It is estimated that the halftone dot portion is thinned because the side edge portion that is not hardened is destroyed by the pressure during printing.
By adding at least one compound represented by formula (1) containing a carboxylic acid group as an ethylenically unsaturated compound, the permeability of the developer can be improved, and the side edge portion is developed and removed. Therefore, it is presumed that the thinning of the halftone dots during printing can be suppressed.
On the other hand, the addition of a surfactant or the like can also improve the developer permeability and improve the developability, but also promotes the penetration of the developer into the image area, thereby reducing the printing durability.
By adding at least one compound represented by the formula (1), it is possible to improve the developability of the non-image area only when penetrating with an alkali developer, and the image area has an ethylenically unsaturated group formed by a polymerization reaction. By curing, the developer permeability can be suppressed. As described above, the non-image area can promote the penetration of the developer, and the image area can suppress the penetration of the developer, so that the thinning of the halftone dot portion during printing can be suppressed while maintaining the printing durability. I guess it. At the same time, since it has a carboxylic acid group, the dispersibility in the developer is also improved, and it is assumed that the development residue derived from the ethylenically unsaturated compound can be significantly suppressed.

<Support>
The support that can be used for the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like hydrophilic support. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) , Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), aluminum, zinc, copper, etc., or paper or plastic film laminated or vapor-deposited. . A preferable support includes a polyester film and an aluminum plate. Among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or a plastic laminated on a thin film of aluminum or aluminum alloy. Examples of the foreign element 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 weight or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion between the photosensitive layer and the support. Prior to the roughening treatment of the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (electrochemical surface roughening treatment that dissolves the surface), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, and further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used and cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by weight solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within the above range, good printing durability and good scratch resistance of the non-image area of the planographic printing plate can be obtained.

  As the support, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement of adhesiveness to the upper layer, hydrophilicity, resistance to contamination, heat insulation, etc., as necessary. Then, the micropore enlargement treatment, the micropore sealing treatment of the anodized film, and the aqueous solution containing the hydrophilic compound described in JP-A Nos. 2001-253181 and 2001-322365 are immersed in the aqueous solution. A surface hydrophilization treatment or the like can be selected as appropriate. Of course, the enlargement process and the sealing process are not limited to those described above, and any conventionally known method can be performed.

Sealing treatment includes vapor sealing, single treatment with zirconic fluoride, treatment with aqueous solution containing inorganic fluorine compounds such as treatment with sodium fluoride, vapor sealing with addition of lithium chloride, sealing with hot water. Hole processing is also possible.
Among these, a sealing treatment with an aqueous solution containing an inorganic fluorine compound, a sealing treatment with water vapor, and a sealing treatment with hot water are preferable.

  The hydrophilization treatment is described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

When using a support with insufficient surface hydrophilicity, such as a polyester film, it is preferable to apply a hydrophilic layer to make the surface hydrophilic.
The hydrophilic layer is at least selected from the group consisting of beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metals described in JP-A-2001-199175. Obtained by crosslinking or pseudo-crosslinking a hydrophilic layer formed by coating a coating solution containing one elemental oxide or hydroxide colloid, or an organic hydrophilic polymer described in JP-A-2002-79772. A hydrophilic layer having an organic hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or metal oxide Hydrophilic layer comprising an inorganic thin film having a surface containing Preferred. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within the above range, good adhesion to the photosensitive layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within the above range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

<Image forming layer>
The image forming layer (hereinafter also referred to as “photosensitive layer”) in the lithographic printing plate precursor according to the present invention comprises, as basic components, (i) a binder polymer, (ii) an ethylenically unsaturated compound, and (iii) a polymerization initiator. contains.

((I) binder polymer)
The photosensitive layer in the lithographic printing plate precursor according to the invention contains a binder polymer.
The binder polymer is a polymer that functions as a film-forming agent for the photosensitive layer, and preferably contains a linear organic polymer. As such a “linear organic polymer”, known ones can be used.
Examples of such binder polymers are preferably polymers selected from the group consisting of acrylic resins, polyvinyl acetal resins, polyurethane resins, polyamide resins, epoxy resins, methacrylic resins, styrene resins, and polyester resins. Of these, acrylic resins and polyurethane resins are more preferable. Here, the “acrylic resin” refers to an acrylic polymer having an acrylic acid derivative as a (co) polymerization component. “Polyurethane resin” refers to a polymer produced by a condensation reaction of a compound having two isocyanate groups and a compound having two or more hydroxyl groups.

Further, the binder polymer can be cross-linked in order to improve the film strength of the image area.
In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.

  Here, the crosslinkable group is a group that crosslinks the polymer binder in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can carry out addition polymerization reaction. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, an onium salt structure etc. are mentioned, for example. Among these, an ethylenically unsaturated bond group is preferable, and functional groups represented by the following formulas (1 ′) to (3 ′) are particularly preferable.

In the formula (1 ′), R ^{1 to} R ³ each independently represents a monovalent organic group.
R ¹ preferably includes a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom or a methyl group is more preferable because of high radical reactivity.
R ² and R ³ are each independently a hydrogen atom, a halogen atom, an amino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an optionally substituted alkyl group, or a substituent. An aryl group that may have a substituent, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent Arylamino group which may have a substituent, an arylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, etc., among which a hydrogen atom, a carboxyl group, an alkoxycarbonyl group and a substituent are included. An alkyl group which may be substituted and an aryl group which may have a substituent are preferable because of high radical reactivity.

X represents an oxygen atom, a sulfur atom, or N (R ¹² ), and R ¹² represents a hydrogen atom or a monovalent organic group. Here, examples of R ¹² include an alkyl group which may have a substituent. Among them, a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group is preferable because of high radical reactivity.

  Here, the substituents that can be introduced include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, alkoxy groups, aryloxy groups, halogen atoms, amino groups, alkylamino groups, arylamino groups, carboxyl groups, alkoxycarbonyl groups, A sulfo group, a nitro group, a cyano group, an amide group, an alkylsulfonyl group, an arylsulfonyl group and the like can be mentioned.

In the formula (2 ′), R ^{4 to} R ⁸ each independently represents a monovalent organic group.
R ^{4 to} R ⁸ are preferably a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, An aryl group that may have a substituent, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent. An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are more preferable.
Examples of the substituent that can be introduced are the same as those in the formula (1 ′).

Y represents an oxygen atom, a sulfur atom, or N (R ¹² ). R ¹² has the same meaning as R ^{12 in} formula (1 ′), and preferred examples thereof are also the same.

In the formula (3 ′), R ^{9 to} R ¹¹ each independently represents a monovalent organic group.
R ⁹ is preferably a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom or a methyl group is more preferable because of high radical reactivity.
R ¹⁰ and R ¹¹ are independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, An aryl group that may have a substituent, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent. An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.
Here, examples of the substituent that can be introduced are the same as those in the formula (1 ′).

Z represents an oxygen atom, a sulfur atom, N (R ¹³ ), or an optionally substituted phenylene group.
Examples of R ¹³ include an alkyl group which may have a substituent. Among them, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.

  Among these, (meth) acrylic acid copolymers and polyurethane having a crosslinkable group in the side chain are more preferable.

  The binder polymer having crosslinkability, for example, has a free radical (polymerization initiation radical or a growth radical in the polymerization process of the polymerizable compound) added to the crosslinkable functional group, and the polymerization chain of the polymerizable compound is formed directly between the polymers. Through addition polymerization, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded together, thereby causing cross-linking between polymer molecules. Forms and cures.

The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol per 1 g of the binder polymer. More preferably, it is -7.0 mmol, and it is further more preferable that it is 2.0-5.5 mmol.
Further, the binder polymer to be used is appropriately selected according to the mode of the development treatment so that the non-image area of the photosensitive layer can be satisfactorily removed in the plate making process of the lithographic printing plate precursor. Details are given below.

(I-1) Alkali-soluble binder polymer In an embodiment in which the development treatment is performed using an alkali developer, the binder polymer needs to be dissolved in the alkali developer, and therefore an organic polymer that is soluble in alkali water is used. An organic polymer that is preferably used and is soluble in alkaline water having a pH of 8 to 10 is more preferably used.
In order to be soluble in alkaline water, it preferably has an alkali-soluble group. The alkali solubility is preferably an acid group, and examples thereof include a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a hydroxyl group. Among these, a binder polymer having a carboxyl group is particularly preferable from the viewpoint of achieving both film properties, counter-printing properties, and developability.
Furthermore, the alkali-soluble binder polymer can be cross-linked as described above in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.
The alkali-soluble binder polymer preferably has a weight average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, More preferably, it is 000-250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The alkali-soluble binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.
An alkali-soluble binder polymer may be used individually by 1 type, or 2 or more types may be mixed and used for it.
The content of the alkali-soluble binder polymer is preferably 5 to 90% by weight, more preferably 10 to 70% by weight, and more preferably 10 to 60% by weight with respect to the total solid content of the photosensitive layer. Is more preferable. Within the above range, good image area strength and image formability can be obtained.

(I-2) Binder polymer having a hydrophilic group As the binder polymer usable in the photosensitive layer, a binder polymer having a hydrophilic group (hydrophilic group-containing binder polymer) in order to improve developability to a developer. May be used. In particular, when an acidic to weakly alkaline developer is used, a binder polymer having this hydrophilic group is preferably used.

The hydrophilic group is selected from monovalent or divalent or higher hydrophilic groups, for example, an alkyleneoxy group such as hydroxy group, sulfonic acid group, carboxylic acid group, phosphoric acid group, ethyleneoxy group, propyleneoxy group, Primary amino group, secondary amino group, tertiary amino group, salt obtained by neutralizing amino group with acid, quaternary ammonium group, sulfonium group, iodonium group, phosphonium group, amide group, ether group, or Salts obtained by neutralizing acid groups such as carboxylic acid, sulfonic acid, and phosphoric acid are preferred, and primary amino groups, secondary amino groups, tertiary amino groups, salts obtained by neutralizing amino groups with acids, A quaternary ammonium group, an amide group, a hydroxy group, a —CH ₂ CH ₂ O— repeating unit or a —CH ₂ CH ₂ NH— repeating unit is preferred, and a tertiary amino group and an acid group are contained in an amino group-containing compound. Summed , Salts formed by neutralizing an amino group with an acid, quaternary ammonium group is most preferred.

  The hydrophilic group-containing binder polymer is preferably a copolymer, and the ratio of the copolymer component having a hydrophilic group as described above to the total copolymer components of the copolymer is determined from the viewpoint of developability. It is preferably 1 to 70% with respect to all the monomer units constituting the coalescence, more preferably 1 to 50% in consideration of compatibility between developability and printing durability, and 1 to 30%. It is particularly preferred.

  As the skeleton of such a hydrophilic group-containing binder polymer, a polymer selected from the group consisting of acrylic resin, polyvinyl acetal resin, polyvinyl alcohol resin, polyurethane resin, polyamide resin, epoxy resin, methacrylic resin, styrene resin, and polyester resin. It is preferably a molecule. Of these, acrylic resins, methacrylic resins, vinyl copolymers such as styrene resins, and polyurethane resins are particularly preferable.

The hydrophilic group-containing binder polymer preferably has a crosslinkable group as described above.
The crosslinkable group content (content of unsaturated double bond capable of radical polymerization by iodine titration) in the hydrophilic group-containing binder polymer is 0.01 to 10.0 mmol per 1 g of the hydrophilic group-containing binder polymer. Is more preferable, 0.05 to 5.0 mmol is more preferable, and 0.1 to 2.0 mmol is further more preferable.

Further, from the viewpoint of improving printing durability, the crosslinkable group is desirably in the vicinity of the hydrophilic group, and the hydrophilic group and the crosslinkable group may be on the same polymer unit.
The hydrophilic group-containing binder polymer has an alkyl (meth) acrylate or aralkyl ester unit in addition to the unit having the hydrophilic group, the unit having a crosslinkable group, the unit having a hydrophilic group and a crosslinkable group. Is preferred. The alkyl group of the (meth) acrylic acid alkyl ester is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group. Examples of the (meth) acrylic acid aralkyl ester include benzyl (meth) acrylate.

  The hydrophilic group-containing binder polymer preferably has a weight average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2 More preferably, it is 1,000,000-250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The hydrophilic group-containing binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like.
A hydrophilic group containing binder polymer may be used individually by 1 type, or 2 or more types may be mixed and used for it.
The content of the hydrophilic group-containing binder polymer is preferably from 5 to 75% by weight, more preferably from 10 to 70% by weight, based on the total solid content of the photosensitive layer, from the viewpoint of good image area strength and image formability. 10 to 60% by weight is more preferable.

  In addition, the total content of the polymerizable compound and the binder polymer is preferably 80% by weight or less, and more preferably 35 to 75% by weight with respect to the total solid content of the photosensitive layer. It is excellent in a sensitivity and developability as it is the said range.

Specific examples of polymer units constituting the hydrophilic group-containing binder polymer and specific examples of the hydrophilic group-containing binder polymer are shown below, but the present invention is not limited to these examples. In addition, the weight average molecular weight in the following table (Mw, also simply described as “molecular weight” in the following table) is measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. Further, in the following chemical formula, TsO ^- _{is, p-CH 3 C 6 H} 4 SO 3 - is the abbreviation.

((Ii) ethylenically unsaturated compounds)
The ethylenically unsaturated compound in the present invention is an ethylenic double bond that undergoes addition polymerization and cures by the action of a photopolymerization initiator described later when the lithographic printing plate precursor of the present invention is irradiated with actinic rays. Is a compound having one or more. The term “monomer” in the present invention means a concept relative to a so-called polymer substance, and in addition to “monomer” in a narrow sense, “dimer”, “trimer”, “oligomer”. Means a concept that also includes
Further, the ethylenically unsaturated compound used in the photosensitive layer contains at least one compound represented by the formula (1) (hereinafter also referred to as “specific ethylenically unsaturated compound”).

（式（１）中、Ｌは（ｍ＋ｎ）価の連結基を表し、Ｄは下記式（Ａ）〜（Ｄ）で表される基よりなる群から選ばれた基を表し、ｍは１以上の整数を表し、ｎは２以上の整数を表す。）

(In formula (1), L represents a (m + n) -valent linking group, D represents a group selected from the group consisting of groups represented by the following formulas (A) to (D), and m is 1 or more. And n represents an integer of 2 or more.)

（式（Ａ）〜（Ｄ）中、Ｘ、Ｙ及びＺはそれぞれ独立に、酸素原子、硫黄原子又はＮＲ¹⁷を表し、Ｒ⁴〜Ｒ¹⁴及びＲ¹⁷はそれぞれ独立に、水素原子又は一価の有機基を表し、Ｒ¹⁵は水素原子又はメチル基を表し、Ｒ¹⁶は一価の置換基を表し、ｋは０〜４の整数を表す。）

(In the formulas (A) to (D), X, Y and Z each independently represent an oxygen atom, a sulfur atom or NR ¹⁷ , and R ^{4 to} R ¹⁴ and R ¹⁷ each independently represent a hydrogen atom or a monovalent group. R ¹⁵ represents a hydrogen atom or a methyl group, R ¹⁶ represents a monovalent substituent, and k represents an integer of 0 to 4.)

L in Formula (1) is a (m + n) -valent linking group composed of any atom or atomic group, and the way of bonding is not particularly limited.
The (m + n) -valent linking group is preferably a group formed by an element selected from the group consisting of a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom and a halogen atom. A group formed by an element selected from the group consisting of an atom, a nitrogen atom, an oxygen atom and a sulfur atom is more preferred.
The (m + n) -valent linking group is preferably a group having an ether bond, an ester bond, a urethane bond, a thiourethane bond, a urea bond, an aromatic ring, and / or a heterocyclic ring. A group having a bond, a urethane bond, a thiourethane bond, and / or a urea bond is more preferable, and a group having a urethane bond, a thiourethane bond, and / or a urea bond is more preferable, and a urethane bond. Particularly preferred is a group having

M in Formula (1) represents an integer of 1 or more, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, still more preferably 1 or 2, It is particularly preferred.
N in the formula (1) represents an integer of 2 or more, and is preferably an integer of 2 to 10, more preferably an integer of 2 to 6, from the viewpoint of printing durability and developability. It is more preferably an integer of 5, particularly preferably 2 or 3, and most preferably 2.

D in Formula (1) represents a group selected from the group consisting of groups represented by Formulas (A) to (D).
In the formula (A), R ^{4 to} R ⁶ each independently represents a hydrogen atom or a monovalent organic group.
Examples of R ⁴ include a hydrogen atom or an alkyl group which may have a substituent. Among these, specifically, a hydrogen atom, a methyl group, a methylalkoxy group, and a methyl ester group are preferable.
Specific examples of R ⁵ and R ⁶ include a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, and an alkyl which may have a substituent. Group, aryl group which may have a substituent, alkoxy group which may have a substituent, aryloxy group which may have a substituent, alkylamino group which may have a substituent, substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among these, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group that may have a substituent, and an aryl group that may have a substituent are preferable.
Here, examples of the substituent that can be introduced into these groups include a methoxycarbonyl group, an ethoxycarbonyl group, an isopropyloxycarbonyl group, a methyl group, an ethyl group, and a phenyl group.
X in the formula (A) represents an oxygen atom, a sulfur atom, or NR ¹⁷ , preferably an oxygen atom or NR ¹⁷ , and more preferably an oxygen atom. R ¹⁷ represents a hydrogen atom or a monovalent organic group, such as an alkyl group preferably may have a substituent.

In the formula (B), R ^{7 to} R ¹¹ each independently represents a hydrogen atom or a monovalent organic group.
Specific examples of R ^{7 to} R ¹¹ include a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, and an alkyl which may have a substituent. Group, aryl group which may have a substituent, alkoxy group which may have a substituent, aryloxy group which may have a substituent, alkylamino group which may have a substituent, substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among these, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group that may have a substituent, and an aryl group that may have a substituent are preferable.
Here, examples of the substituent that can be introduced into these groups include those exemplified as the substituent that can be introduced in the formula (A).
Wherein the Y in (B), an oxygen atom, a sulfur atom, or represents NR ^17, an oxygen atom, or is preferably NR ^17, and more preferably an oxygen atom. The R ^17, are the same as those for R ¹⁷ in Formula (A).

In the formula (C), R ^{12 to} R ¹⁴ each independently represents a hydrogen atom or a monovalent organic group.
Specific examples of R ^{12 to} R ¹⁴ include a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, and an alkyl which may have a substituent. Group, aryl group which may have a substituent, alkoxy group which may have a substituent, aryloxy group which may have a substituent, alkylamino group which may have a substituent, substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among these, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group that may have a substituent, and an aryl group that may have a substituent are preferable.
Here, examples of the substituent that can be introduced into these groups include those exemplified as the substituent that can be introduced in the formula (A).
Z in formula (C) represents an oxygen atom, a sulfur atom, or NR ¹⁷ , preferably an oxygen atom or NR ¹⁷ , and more preferably an oxygen atom. Examples of R ¹⁵ include the same as R ¹⁷ in the formula (A).

R ¹⁵ in formula (D) represents a hydrogen atom or a methyl group, and is preferably a hydrogen atom. R ¹⁵ can be bonded at any position on the benzene ring.
R ¹⁶ in the formula (D) represents a monovalent substituent, and may have a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or a substituent. A good alkyl group, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, Preferable examples include an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, and an arylsulfonyl group which may have a substituent. When two or more R ¹⁶ are present, they may be the same or different.
K in the formula (D) represents an integer of 0 to 4, preferably 0 or 1, and more preferably 0.

From the viewpoints of compatibility with other materials in the photosensitive layer, image forming properties, and printing durability, D in Formula (1) is preferably a group represented by Formula (A).
The specific ethylenically unsaturated compounds may be used alone or in combination of two or more.

It is essential that the specific ethylenically unsaturated compound in the present invention is a compound having a plurality of polymerizable groups and having a carboxyl group, as represented by the formula (1).
There is no restriction | limiting in particular in the synthesis | combining method of a specific ethylenically unsaturated compound, It can synthesize | combine by a well-known method.
For example, an acid group may be introduced by reacting a hydroxyl group of an ethylenically unsaturated compound with a carboxylic acid anhydride. Specific examples of the carboxylic acid anhydride used in this case include phthalic anhydride, tetrahydrophthalic anhydride, alkylated tetrahydrophthalic anhydride, hexahydrophthalic anhydride, alkylated hexahydrophthalic anhydride, and succinic anhydride. Examples include acid and maleic anhydride.

The specific ethylenically unsaturated compound is preferably an ester of an aliphatic polyhydroxy compound and an unsaturated carboxylic acid, and in this ester, the aliphatic polyhydroxy compound may be pentaerythritol and / or dipentaerythritol. More preferred. The ester of the aliphatic polyhydroxy compound and the unsaturated carboxylic acid is a polyfunctional monomer having an acid group by reacting an unreacted hydroxyl group of the aliphatic polyhydroxy compound with a non-aromatic carboxylic acid anhydride. It is preferable.
The specific ethylenically unsaturated compound can also be obtained by reacting an isocyanate compound having an ethylenically unsaturated group with a carboxylic acid precursor such as a carboxylic acid group or a carboxylic acid ester and an active hydrogen compound such as an amine, thiol or hydroxyl group. Can be done.

  From the viewpoint of compatibility with other materials in the photosensitive layer, image formability, and printing durability, the specific ethylenically unsaturated compound most preferably has a urethane skeleton, a thiourethane skeleton, and / or a urea skeleton. It is mentioned as a preferred embodiment.

  Specific examples of the specific ethylenically unsaturated compound suitably used in the present invention are shown below, but the present invention is not limited to these.

  Among the specific examples of the compound represented by the formula (1), (1), (2), (7), (8), (9), (10), (21), (22), (24 ), (27), (29), (31), (32), (34), (37), (39), (43), (44), (46), (49), (51), (52), (54), (55), (56) and (63) are preferred, (29), (43), (46) and (48) are more preferred, and (29) and (43) Is particularly preferred.

  The amount of the ethylenically unsaturated compound used is preferably from 5 to 90% by weight, more preferably from 20 to 75% by weight, based on the total solid content of the photosensitive layer.

  As the ethylenically unsaturated compound used for the photosensitive layer, it is preferable to use (ii) one or more other ethylenically unsaturated compounds in combination with the compound represented by the formula (1).

  The content of the other ethylenically unsaturated compounds used in combination is preferably 1 to 90% by weight, more preferably 20 to 85% by weight, based on the total weight of all ethylenically unsaturated compound components. 50 to 80% by weight is more preferable.

As other ethylenically unsaturated compounds that can be used in combination, conventionally known compounds can be used without limitation, and can be arbitrarily selected from compounds having at least one ethylenically unsaturated double bond, preferably two or more. it can. For example, it has chemical forms such as monomers, prepolymers, that is, dimers, trimers and oligomers, copolymers thereof, and mixtures thereof.
Examples of monomers include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and aliphatic polyhydric alcohol compounds, unsaturated carboxylic acids and aliphatic Examples include amides with polyvalent amine compounds.

The following monomers are mentioned as a specific example of the monomer of the ester of an aliphatic polyhydric alcohol compound and unsaturated carboxylic acid.
Acrylic esters include ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylol Methylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate Dipentaerythritol diacrylate, Pentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomers and the like.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p (3-methacryloxy-2-hydroxypropoxy) phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane and the like.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate

Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.
Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.
Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bisacrylamide, methylene bismethacrylamide, 1,6-hexamethylene bisacrylamide, 1,6-hexamethylene bismethacrylamide, Examples include diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

Further, urethane acrylates as described in JP-A-51-37193, JP-A-48-64183, JP-B-49-43191 and JP-B-52-30490 are described. Polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid can be used. Furthermore, the Japan Adhesion Association Vol. 20, no. 7, 300-308 (1984), and photocurable monomers and oligomers can also be used.
Specifically, NK oligo U-4HA, U-4H, U-6HA, U-6ELH, U-108A, U-1084A, U-200AX, U-122A, U-340A, U-324A, UA-100 (Manufactured by Shin-Nakamura Chemical Co., Ltd.), UA-306H, AI-600, UA-101T, UA-101I, UA-306T, UA-306I (manufactured by Kyoeisha Chemical Co., Ltd.), Art Resin UN-9200A, UN -3320HA, UN-3320HB, UN-3320HC, SH-380G, SH-500, SH-9832 (manufactured by Negami Industrial Co., Ltd.), PLEX6661-O (manufactured by Degussa, Germany), and the like.

((Iii) polymerization initiator)
The photosensitive layer in the lithographic printing plate precursor according to the invention contains a polymerization initiator (hereinafter also referred to as “initiator compound”).
The initiator compound is a compound that undergoes an action such as electron transfer, energy transfer, and heat generation caused by the electronically excited state of the sensitizing dye to generate a chemical change and generate at least one selected from radicals, acids, and bases. It is. Hereinafter, radicals, acids, and bases generated in this way are simply referred to as active species. When the initiator compound is not present or when only the initiator compound is used alone, practically sufficient sensitivity cannot be obtained. As one mode in which a sensitizing dye and an initiator compound are used in combination, they can be used as a single compound by an appropriate chemical method (such as linking a sensitizing dye and an initiator compound through a chemical bond). It is.

  Usually, many of these initiator compounds are considered to generate active species through the initial chemical processes represented by the following (1) to (3). (1) Reductive decomposition of the initiator compound based on the electron transfer reaction from the electronically excited state of the sensitizing dye to the initiator compound, (2) Electron transfer from the initiator compound to the electronically excited state of the sensitizing dye (3) decomposition of the initiator compound from the electronically excited state based on energy transfer from the electronically excited state of the sensitizing dye to the initiator compound. In many cases, it is ambiguous as to which type (1) to (3) each initiator compound belongs, but the sensitizing dye in the present invention can be combined with any of these types of initiator compounds. Shows a high sensitizing effect.

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

Examples of hexaarylbiimidazole compounds include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5. , 5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2, 2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5 ′ -Tetraphenylbiimidazole 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5 Examples include 5′-tetraphenylbiimidazole.
The hexaarylbiimidazole compound is particularly preferably used in combination with a sensitizing dye having a maximum absorption at 300 to 450 nm.

  The onium salt suitably used in the present invention (in the present invention, functions as an ionic polymerization initiator, not as an acid generator) is represented by the following formulas (RI-I) to (RI-III). Onium salt.

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and a carbon number. 1-12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C1-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamide groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyl groups And a thioaryl group having 1 to 12 carbon atoms.
Wherein _{(RI-I), Z 11} - represents a monovalent anion, specifically a halogen ion, a perchlorate ion, a hexafluorophosphate ion, a tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, A sulfate ion is mentioned. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable from the viewpoint of stability.

In the formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include 1 to 1 carbon atoms. 12 alkyl groups, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, Halogen atom, C1-C12 alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 1 to 12 carbon atoms.
Wherein _{(RI-II), Z 21} - represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of stability and reactivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl group having 20 or less carbon atoms which may have 1 to 6 substituents. Represents. Among them, an aryl group is preferable from the viewpoint of reactivity and stability.
Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms.
Wherein _{(RI-III), Z 31} - represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Of these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. Further, carboxylate ions described in JP-A No. 2002-148790 or JP-A No. 2001-343742 are more preferable, and carboxylate ions described in JP-A No. 2002-148790 are particularly preferable.
The onium salt is particularly preferably used in combination with an infrared absorber having a maximum absorption at 750 to 1,400 nm.

  As other polymerization initiators, JP-A 2007-171406, JP-A 2007-206216, JP-A 2007-206217, JP-A 2007-225701, JP-A 2007-225702, JP The polymerization initiators described in JP 2007-316582 A and JP 2007-328243 A can be preferably used.

The polymerization initiator in the photosensitive layer is suitably used alone or in combination of two or more.
The amount of the polymerization initiator used in the photosensitive layer is preferably 0.01 to 20% by weight, more preferably 0.1 to 15% by weight, based on the total weight of the total solid content of the photosensitive layer. More preferably, it is 1.0 to 10% by weight.

(Sensitizing dye)
The photosensitive layer preferably contains a sensitizing dye.
As the sensitizing dye, for example, a sensitizing dye having a maximum absorption at 300 to 450 nm, a sensitizing dye having a maximum absorption at 500 to 600 nm, and an infrared absorber having a maximum absorption at 750 to 1,400 nm are added. Thus, it is possible to provide a high-sensitivity lithographic printing plate corresponding to a 405 nm violet laser, a 532 nm green laser, and a 803 nm IR laser, which are usually used in the industry.
First, a sensitizing dye having a maximum absorption in the wavelength region of 350 to 450 nm will be described.
Examples of such sensitizing dyes include merocyanine dyes, benzopyrans, coumarins, aromatic ketones and anthracenes.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 360 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following formula (IX).

（式（IX）中、Ａは置換基を有してもよい芳香族環基又はヘテロ環基を表し、Ｘは酸素原子、硫黄原子又はＮ−（Ｒ₃）を表し、Ｒ₁、Ｒ₂及びＲ₃はそれぞれ独立に、一価の非金属原子団を表し、ＡとＲ₁及びＲ₂とＲ₃とはそれぞれ互いに結合して、脂肪族性又は芳香族性の環を形成してもよい。）

(In the formula (IX), A represents an aromatic ring group or a heterocyclic group which may have a substituent, X represents an oxygen atom, a sulfur atom or N- (R ₃ ), and R ₁ , R ₂ And R ₃ each independently represents a monovalent nonmetallic atomic group, and A and R ₁ and R ₂ and R ₃ may be bonded to each other to form an aliphatic or aromatic ring. Good.)

Formula (IX) will be described in more detail.
R ₁ , R ₂ and R ₃ in formula (IX) are each independently a monovalent non-metallic atomic group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, substituted or unsubstituted aryl It is preferably a group, a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, or a halogen atom.

Next, A in the formula (IX) will be described.
A represents an aromatic ring group or a heterocyclic group which may have a substituent. Specific examples of the aromatic ring or heterocyclic ring which may have a substituent include R ₁ in formula (IX), It includes the same as those described for R ₂ and R _3.

  As specific examples of such sensitizing dyes, compounds described in paragraphs 0047 to 0053 of JP-A-2007-58170 are preferably used.

  Furthermore, sensitizing dyes represented by the following formulas (V) to (VII) can also be used.

In formula (V), R < ¹ > -R < ¹⁴ > represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom each independently. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
In the formula (VI), R ^{15 to} R ³² each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.

In formula (VII), R ¹ , R ² and R ³ each independently represent a halogen atom, an alkyl group, an aryl group, an aralkyl group, an —NR ⁴ R ⁵ group or an —OR ⁶ group, and R ⁴ , R ⁵ And R ⁶ each independently represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and k, m and n each independently represents an integer of 0 to 5.

Also, JP 2007-171406 A, JP 2007-206216 A, JP 2007-206217 A, JP 2007-225701 A, JP 2007-225702 A, JP 2007-316582 A, Sensitizing dyes described in JP-A-2007-328243 can also be preferably used.
The preferred addition amount of the sensitizing dye is preferably 0.05 to 30 parts by weight, more preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the total solid content of the photosensitive layer. More preferably, it is 2 to 10 parts by weight.

Subsequently, a sensitizing dye having a maximum absorption at 750 to 1,400 nm that is preferably used in the present invention will be described in detail.
The sensitizing dye used here is highly sensitive to infrared laser irradiation (exposure) and is in an electronically excited state. The electron transfer, energy transfer, heat generation (photothermal conversion function), etc., associated with the electronically excited state are the photosensitive layer. It is presumed that it acts on a polymerization initiator coexisting therein to cause a chemical change in the polymerization initiator to generate active species such as radicals, acids and bases. In any case, the addition of a sensitizing dye having a maximum absorption at 750 to 1,400 nm is particularly suitable for plate making directly drawn with an infrared laser beam having a wavelength of 750 to 1,400 nm. Compared with a printing plate precursor, it can exhibit high image forming properties.

  The infrared absorber is preferably a dye having an absorption maximum at a wavelength of 750 nm to 1,400 nm.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Of these dyes, cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes are preferred, and cyanine dyes and indolenine cyanine dyes are more preferred, and are represented by the following formula (a). Particularly preferred are cyanine dyes.

In the formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh ₂ , X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 12 carbon atoms including a hetero atom. Represents a hydrocarbon group. Here, the hetero atom represents N, S, O, a halogen atom, or Se.
X _a ^- is, Z _a to be 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, and, a substituent selected from the group consisting of a halogen atom Represents.

R ¹ and R ² each independently represents 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 6-membered ring. It is particularly preferable that a 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.
Furthermore, Za ^- represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by the formula (a) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion or a sulfonate ion, particularly preferably a perchlorate ion, from the storage stability of the photosensitive layer coating solution. Hexafluorophosphate ion or aryl sulfonate ion. It is particularly preferable that the counter ion does not contain a halogen ion.

  Examples of pigments include commercially available pigments, Color Index (CI) Handbook, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), The pigments described in “Printing Ink Technology” published by CMC (published in 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

  These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Applications of Metal Soap” (Yokoshobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. Within this preferred particle size range, excellent dispersion stability of the pigment in the photosensitive layer can be obtained, and a uniform photosensitive layer can be obtained.

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

  These infrared absorbers may be added to the same layer as other components, or another layer may be provided and added thereto.

  The addition amount of these infrared absorbers is preferably 0.01 to 50% by weight with respect to the total solid content constituting the photosensitive layer, from the viewpoint of uniformity in the photosensitive layer and durability of the photosensitive layer. The amount is preferably 0.1 to 10% by weight, more preferably 0.5 to 10% by weight in the case of dyes, and 0.1 to 10% by weight in the case of pigments. It is particularly preferred.

(Micro capsule)
In the present invention, as a method for causing the photosensitive layer to contain the above-mentioned photosensitive layer constituents and other constituents described later, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, A part of the components can be encapsulated in microcapsules and added to the photosensitive layer. In that case, each component can be contained in any ratio in and outside the microcapsules.

As a method for microencapsulating the photosensitive layer constituent components, known methods can be applied.
For example, as a method for producing microcapsules, a method using coacervation described in U.S. Pat. Nos. 2,800,047 and 2,800,498, each specification of U.S. Pat. No. 3,287,154, and Japanese Patent Publication No. 38-19574. No. 42-446, a method based on an interfacial polymerization method, U.S. Pat. Nos. 3,418,250 and 3,660,304, a method based on polymer precipitation, and U.S. Pat. No. 3,796,669. Described in US Pat. No. 3,914,511, US Pat. No. 3,914,511, US Pat. No. 3,014,376, US Pat. No. 4,087,376, US Pat. No. 4,089,802. Urea-formaldehyde system or urea formaldehyde A method using a lucinol-based wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose described in US Pat. No. 4,025,445, Japanese Patent Publication Nos. 36-9163 and 51-9079 In situ method by monomer polymerization described in U.S. Pat. No. 3,930,422, spray drying method described in U.S. Pat. No. 3,111,407, U.S. Pat. No. 3,521,807, U.S. Pat. Although there is an electrolytic dispersion cooling method, it is not limited to these.

  A preferable microcapsule wall has three-dimensional cross-linking and a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, or a mixture thereof, and polyurea or polyurethane is particularly preferable. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into said water-insoluble polymer.

  The average particle size of the microcapsules is preferably 0.01 to 3.0 μm, more preferably 0.05 to 2.0 μm, and particularly preferably 0.10 to 1.0 μm. In the above range, good resolution and stability over time can be obtained.

(Coloring agent)
In the photosensitive layer, a dye having a large absorption in the visible light region can be used as an image colorant. Some colorants have a function as a sensitizing dye as described above.
Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Manufactured by Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc. And dyes described in Japanese Patent No. -293247.

A pigment is also preferably used as the colorant.
As the pigment, pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide can be suitably used, and phthalocyanine pigments are most preferably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is preferably 0.01 to 10% by weight based on the total solid content of the photosensitive layer.

(Other photosensitive layer components)
The photosensitive layer may further contain various additives as necessary. Additives include surfactants for improving developability and improving the surface of the coating, hydrophilic polymers for improving developability and improving the dispersion stability of microcapsules, and visual and non-image areas. A colorant and a print-out agent, a polymerization inhibitor for preventing unnecessary thermal polymerization of a radically polymerizable compound during production or storage of the photosensitive layer, a higher fat derivative for preventing polymerization inhibition by oxygen, Add inorganic particles to improve the cured film strength of the image area, hydrophilic low molecular weight compounds to improve developability, co-sensitizers and chain transfer agents to improve sensitivity, plasticizers to improve plasticity, etc. be able to. Any of these compounds can be used, for example, JP 2007-171406 A, JP 2007-206216 A, JP 2007-206217 A, JP 2007-225701 A, JP 2007 A1. The compounds described in JP-A-225702, JP-A-2007-316582, and JP-A-2007-328243 can be used.

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

  In the photosensitive layer of the present invention, in particular, a thiol compound (for example, 2-mercaptobenzimidazoles, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 3-mercaptotriazoles, 5-mercaptotetrazoles, etc.) Can be preferably used as a chain transfer agent.

  Among these, a thiol compound represented by the following formula (S) is particularly preferably used. By using the thiol compound represented by the formula (S) as a chain transfer agent, avoiding a decrease in sensitivity due to evaporation from the photosensitive layer or diffusion to other layers, excellent storage stability, and also high sensitivity and high resistance. A lithographic printing plate precursor for printing is obtained.

  In formula (S), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent, and A represents a 5-membered ring having a carbon atom together with an N = CN moiety. Alternatively, it represents an atomic group that forms a 6-membered heterocycle, and A may further have a substituent.

<Formation of photosensitive layer>
The photosensitive layer is formed by dispersing or dissolving the necessary components in a solvent to prepare and apply a coating solution.
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-butyllactone, toluene, water, and the like. However, the present invention is not limited to this.
These solvents are used alone or in combination.
The solid content concentration of the coating solution is preferably 1 to 50% by weight.
The photosensitive layer may be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeating a plurality of coating and drying operations.

Moreover, although the photosensitive layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, it is generally preferably 0.3 to 3.0 g / m ² . Within the above range, good sensitivity and good film properties of the photosensitive layer can be obtained.
Various methods can be used as the coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Protective layer>
In the lithographic printing plate precursor according to the invention, a protective layer (oxygen blocking layer) is preferably provided on the photosensitive layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure.
The protective layer preferably has an oxygen permeability A of 1.0 ≦ A ≦ 20 (mL / m ² · day) at 25 ° C. and 1 atmosphere. When the oxygen permeability A is 1.0 (mL / m ² · day) or more, an unnecessary polymerization reaction during production and raw storage can be suppressed, and unnecessary fogging and image line weighting may occur during image exposure. It is possible to suppress the occurrence of a problem that occurs. Moreover, when the oxygen permeability A is 20 (mL / m ² · day) or less, the sensitivity is excellent. The oxygen permeability A is more preferably 1.5 ≦ A ≦ 12 (mL / m ² · day), and further preferably 2.0 ≦ A ≦ 10.0 (mL / m ² · day). preferable.
In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially impede the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and are easy in the development process after exposure. It is preferable that it can be removed. The device concerning such a protective layer has been conventionally made, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol (PVA), vinyl alcohol / vinyl phthalate copolymer, Water-soluble polymers such as vinyl acetate / vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, polyacrylamide, etc. These can be used alone or in combination. Of these, it is preferable to use polyvinyl alcohol as a main component because it gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components.
Specific examples of polyvinyl alcohol include those that are hydrolyzed from 71 to 100 mol% and have a polymerization repeating unit in the range of 300 to 2,400.
Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8 and the like. These can be used alone or in combination. As a preferred embodiment, the content of polyvinyl alcohol in the protective layer is preferably 20 to 95% by weight, and more preferably 30 to 90% by weight.

  Moreover, well-known modified polyvinyl alcohol can also be used preferably. For example, various hydrophilic modification sites such as anion modification sites modified with anions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the anion-modified site, the cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol and various organic acids. Examples thereof include polyvinyl alcohol having various polymerization degrees having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, and the like.

  As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoints of oxygen barrier properties, development removability, and the content in the protective layer is 3.5 to 80% by weight. Is preferable, 10 to 60% by weight is more preferable, and 15 to 30% by weight is further preferable.

Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity.
The molecular weight of the (co) polymer such as polyvinyl alcohol (PVA) is preferably in the range of 2,000 to 10 million, more preferably in the range of 20,000 to 3 million.

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added to the (co) polymer in an amount corresponding to several weight% to give flexibility, and sodium alkyl sulfate, Anionic surfactants such as sodium alkyl sulfonates; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to (co) polymers On the other hand, several weight% can be added.

  In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is contained in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesion can be obtained by mixing 20 to 60% by weight and laminating on a photosensitive layer. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method of the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

Furthermore, the protective layer in the lithographic printing plate precursor preferably contains an inorganic layered compound for the purpose of improving oxygen barrier properties and photosensitive layer surface protection.
Here, the inorganic stratiform compound is a particle having a thin tabular shape, for example, the following formula _{A (B, C) 2-5 D} 4 O 10 (OH, F, O) 2
(In the formula, A represents any of K, Na, and Ca, B and C represent any of Fe (II), Fe (III), Mn, Al, Mg, and V, and D represents Si or Al. To express.)
And mica groups such as natural mica, synthetic mica, and the like, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by 3MgO.4SiO.H ₂ O.
In the present invention, among the inorganic layered compounds, fluorine-based swellable synthetic mica, which is a synthetic inorganic layered compound, is particularly useful.
The aspect ratio of the inorganic stratiform compound is preferably 20 or more, more preferably 100 or more, and further preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured from, for example, a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  The average major axis of the inorganic layered compound is preferably 0.3 to 20 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to 5 μm. The average thickness of the particles is preferably 0.1 μm or less, more preferably 0.05 μm or less, and further preferably 0.01 μm or less. For example, the size of the swellable synthetic mica that is a representative compound among the inorganic layered compounds is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When particles of inorganic layered compounds with a large aspect ratio are contained in the protective layer, the coating film strength is improved and the permeation of oxygen and moisture can be effectively prevented. Even when stored for a long time under high humidity conditions, the storage stability of the planographic printing plate precursor is not deteriorated due to changes in humidity, and the storage stability is excellent.

  It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by weight ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of kinds of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-mentioned weight ratio.

  The dispersion method of the inorganic stratiform compound used for the protective layer is disclosed in JP 2007-171406 A, JP 2007-206216 A, JP 2007-206217 A, JP 2007-225701 A, and JP 2007-225702 A. The methods described in Japanese Patent Laid-Open No. 2007-316582 and Japanese Patent Laid-Open No. 2007-328243 are used.

The coating amount of the protective layer is preferably 0.05 to 10 g / m ^{2 in} terms of the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 0.5 g / The range of m ² is more preferable, and in the case where no inorganic layered compound is contained, the range of 0.5 to 5 g / m ² is more preferable.

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the photosensitive layer is provided on the undercoat layer. The undercoat layer reinforces the adhesion between the support and the photosensitive layer in the exposed area, and easily peels the photosensitive layer from the support in the unexposed area, thereby improving the developability.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably. Particularly preferable compounds include compounds having a polymerizable group such as a methacryl group or an allyl group and a support adsorbing group such as a sulfonic acid group, a phosphoric acid group, or a phosphoric acid ester. A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound.
The coating amount (solid content) of the undercoat layer is preferably 0.1-100 mg / m ^2, more preferably 1 to 30 mg / m ^2.

<Back coat layer>
After the surface treatment is performed on the support or after the undercoat layer is formed, a backcoat layer can be provided on the back surface of the support, if necessary.
Examples of the back coat layer include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organic metal compounds or inorganic metal compounds described in JP-A-6-35174, and the like. Preferable examples include a coating layer made of a metal oxide. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

[Method for producing planographic printing plate]
Next, a method for producing a lithographic printing plate using the lithographic printing plate precursor according to the invention will be described in detail.
The method for producing a lithographic printing plate according to the present invention includes an exposure process for image exposure of the lithographic printing plate precursor according to the present invention, and a development process for removing the photosensitive layer in the non-exposed area in the presence of a developer having a buffering capacity. It is characterized by that.
Further, if necessary, a step of exposing and / or heating the lithographic printing plate precursor between the exposure step and the development step and / or after the development step may be provided.

Image exposure of a lithographic printing plate precursor is performed by a method of exposing through a transparent original image having a line image, a halftone dot image or the like, a method of laser beam scanning with digital data, or the like. Especially, in the said exposure process, it is preferable to image-expose with a laser.
There is no restriction | limiting in particular in the wavelength of an exposure light source, Although it can select suitably according to a polymerization initiator and a sensitizing dye, It is preferable that they are 350 nm-450 nm, or 760 nm-1,200 nm.
As an available laser light source that emits light of 350 nm to 450 nm, the following can be used.
As a gas laser, Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), He—Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and solid laser as Nd: YAG Combination of (YVO4) and SHG crystal × 2 times (355 nm, 5 mW to 1 W), combination of Cr: LiSAF and SHG crystal (430 nm, 10 mW), semiconductor laser system, KNbO3 ring resonator (430 nm, 30 mW), waveguide Type wavelength conversion element and combination of AlGaAs and InGaAs semiconductor (380 nm to 450 nm, 5 mW to 100 mW), combination of waveguide type wavelength conversion element and AlGaInP and AlGaAs semiconductor (300 nm to 350 nm, 5 mW to 100 mW), lGaInN (350nm~450nm, 5mW~30mW), other, N ₂ laser as a pulse laser (337 nm, pulse 0.1~10mJ), XeF (351nm, pulse 10 to 250 mJ). Among these, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 400 to 410 nm, 5 to 30 mW) is preferable in terms of wavelength characteristics and cost.

Regarding the lithographic printing plate precursor exposure apparatus of the scanning exposure method, the exposure mechanism may be any of an inner drum method, an outer drum method, and a flat bed method, and a light source that can oscillate continuously is preferably used. .
Other exposure light sources that can be used in the present invention include ultra high pressure, high pressure, medium pressure, and low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, various visible and ultraviolet laser lamps, fluorescent lamps. A lamp, a tungsten lamp, sunlight, etc. are also mentioned.

Although it does not specifically limit as an available laser light source which emits 760 nm-1,200 nm light, A solid laser and semiconductor laser which radiate | emit infrared rays with a wavelength of 760-1,200 nm are mentioned suitably. The output of the infrared laser is preferably 100 mW or more. In order to shorten the exposure time, it is preferable to use a multi-beam laser device. The exposure time per pixel is preferably within 20 μsec. Moreover, it is preferable that irradiation energy amount is 10-300 mJ / cm < ² >. As the light source, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 5 to 30 mW) is suitable in terms of wavelength characteristics and cost.

Next, the development process will be described in detail.
In the development process using a conventional lithographic printing plate precursor, strong alkali development is performed, whereas the lithographic printing plate precursor of the present invention can also be subjected to weak alkali development.
In addition, the lithographic printing plate precursor according to the present invention can produce a lithographic printing plate that is more excellent in developability and the like when subjected to weak alkali development than when subjected to conventional strong alkali development.
Furthermore, it is preferable that the developing step is a step in which the removal of the photosensitive layer in the non-exposed area and the gumming process are performed with one liquid. In the case where the lithographic printing plate precursor according to the invention has a protective layer, the development step is preferably a step in which the protective layer is removed, the photosensitive layer in the non-exposed area is removed, and the gumming process is performed in one liquid. .
The developer in the developing step is preferably a water-soluble polymer compound added to the developer. In the development process using the conventional lithographic printing plate precursor, the protective layer is removed by the pre-water washing process, then alkali development is performed, the alkali is removed by the post-water washing process, the gum treatment is performed in the gumming process, and the drying process. In contrast to drying with a water-soluble polymer compound, the development and gumming can be carried out simultaneously by adding a water-soluble polymer compound to the developer. Further, when the water-soluble polymer compound is added to the developer as described above, the post-water washing step is not particularly required, and the drying step can be performed after developing and gumming with one solution. Further, since the protective layer can be removed simultaneously with development and gumming, it is the most preferable form in that no pre-water washing step is required. Furthermore, after development and gumming, it is preferable to perform drying after removing excess processing liquid using a squeeze roller or the like.

The developing solution in the developing step may be a developing solution having a pH buffering ability, and an aqueous solution having a pH buffering ability is preferably used. By exhibiting the buffering effect, even if the developer is used for a long period of time, fluctuations in pH can be suppressed, and development deterioration due to pH fluctuations, development debris generation, and the like can be suppressed.
The pH of the developer is preferably 7.0 to 12.0, more preferably 7.5 to 11.0, and most preferably 8.0 to 10.5 in terms of developability and environment.

Any pH buffering agent can be used without particular limitation as long as it exhibits a pH buffering effect.
In the present invention, an alkaline buffer is preferably used. For example, (a) carbonate ion and hydrogen carbonate ion, (b) borate ion, (c) water-soluble amine compound and ion of the amine compound, and The combined use etc. are mentioned. That is, for example, (a) a combination of carbonate ion-bicarbonate ion, (b) borate ion, or (c) a combination of water-soluble amine compound-ion of the amine compound, etc., has pH buffering action in the developer. Thus, even if the developer is used for a long period of time, it is possible to suppress fluctuations in pH, and it is possible to suppress development deterioration due to fluctuations in pH, development debris generation, and the like. Particularly preferred is a combination of carbonate ions and bicarbonate ions.

(A) In order to allow carbonate ions and hydrogen carbonate ions to exist in the developer, carbonate and bicarbonate may be added to the developer, or the pH is adjusted after adding carbonate or bicarbonate. Thus, carbonate ions and hydrogen carbonate 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.

(B) To make boric acid ions present in the developer, after adding boric acid and / or borate to the developer, the pH is adjusted using an alkali or using an alkali and an acid. Thus, an appropriate amount of borate ions is generated.
The boric acid and borate used here are not particularly limited, but known boric acid and borate can be used.
Examples of boric acid include orthoboric acid, metaboric acid, and tetraboric acid. Among them, orthoboric acid and tetraboric acid are preferable. Boric acid may be used alone or in combination of two or more.
Examples of the borate include alkali metal salts or alkaline earth metal salts, orthoborate, diborate, metaborate, tetraborate, pentaborate, octaborate. Among them, orthoborate, tetraborate, especially alkali metal tetraborate are preferable. Preferred tetraborate salts include sodium tetraborate, potassium tetraborate, and lithium tetraborate. Among them, sodium tetraborate is preferable. A borate may be used individually by 1 type, or may be used together 2 or more types.
As boric acid and / or borate that can be used in the present invention, orthoboric acid, tetraboric acid and / or sodium tetraborate are particularly preferable. Boric acid and borates may be used in combination with the developer.

(C) The water-soluble amine compound ions can be generated in an aqueous solution of the water-soluble amine compound, and an alkali or acid may be further added to the aqueous solution of the water-soluble amine compound. It can be made to contain in the aqueous solution by adding the compound which becomes.
The water-soluble amine compound is not particularly limited, but a water-soluble amine compound having a group that promotes water solubility is preferable. Examples of the group that promotes water solubility include a carboxylic acid group, a sulfonic acid group, a sulfinic acid group, a phosphonic acid group, and a hydroxyl group. The water-soluble amine compound may have a plurality of these groups.
When the water solubility of an amine compound is promoted by a carboxylic acid group, a sulfonic acid group, a sulfinic acid group, or a phosphonic acid group, it corresponds to an amino acid. The amino acid is in an equilibrium state in an aqueous solution, and when the acid group is, for example, a carboxylic acid group, the equilibrium state is expressed as follows. The amino acid in the present invention means the following B state, and the amino acid ion means the following C state. As the counter ion in the C state, sodium ion and potassium ion are preferable.
[Equilibrium state of amino acid (when acid group is carboxylic acid)]

（例えば、Ｒ¹及びＲ²はそれぞれ独立に、水素原子、アルキル基、アリール基などを表し、Ｒは連結基を表す。）

(For example, R ¹ and R ² each independently represents a hydrogen atom, an alkyl group, an aryl group, etc., and R represents a linking group.)

  Specific examples of water-soluble amine compounds having a carboxylic acid group, a sulfonic acid group, or a sulfinic acid group include glycine, iminodiacetic acid, lysine, threonine, serine, aspartic acid, parahydroxyphenylglycine, dihydroxyethylglycine, alanine, Examples thereof include amino acids such as anthranilic acid and tryptophan, fatty acid amine sulfonic acids such as sulfamic acid, cyclohexylsulfamic acid and taurine, and fatty acid amine sulfinic acids such as aminoethanesulfinic acid. Of these, glycine and iminodiacetic acid are preferred.

  Specific examples of water-soluble amine compounds having a phosphonic acid group (including a phosphinic acid group) include 2-aminoethylphosphonic acid, 1-aminoethane-1,1-diphosphonic acid, 1-amino-1-phenylmethane- Examples thereof include 1,1-diphosphonic acid, 1-dimethylaminoethane-1,1-diphosphonic acid, and ethylenediaminopentamethylenephosphonic acid. 2-aminoethylphosphonic acid is particularly preferable.

  A water-soluble amine compound having a hydroxyl group as a group that promotes water solubility means an alkylamine having a hydroxyl group on an alkyl group (state B ′ below), and these ions mean ammonium ions of an amino group ( State A ′) below.

（例えば、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に、水素原子、アルキル基、アリール基などを表す。ただし、Ｒ¹、Ｒ²及びＲ³のうちの少なくとも１つは水酸基を有するアルキル基である。）

(E.g., R ^1, R ² and R ³ are each independently a hydrogen atom, an alkyl group, and aryl group. Provided that at least one alkyl group having a hydroxyl group of R ^1, R ² and R ³ .)

  Specific examples of the water-soluble amine compound having a hydroxyl group include monoethanolamine, diethanolamine, trimethanolamine, triethanolamine, tripropanolamine, and triisopropanolamine. Among these, triethanolamine and diethanolamine are preferable. As the counter ion of ammonium ion, chloride ion is preferable.

  Examples of the alkali that can be used for adjusting the pH include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, and organic alkali agents. , And combinations thereof can be used. As the acid, an inorganic acid such as hydrochloric acid, sulfuric acid, or nitric acid can be used. The pH can be finely adjusted by adding such an alkali or acid.

  The pH of the developer containing (a) carbonate ion and bicarbonate ion that can be used in the present invention is preferably in the range of pH 8.5 to 10.8. When the pH is 8.5 or more, the developability of the non-image area can be improved. On the other hand, when the pH is 10.8 or less, it is difficult to be influenced by carbon dioxide in the air, and the treatment is caused by the influence of carbon dioxide. A decrease in ability can be suppressed. More preferably, it is the range of pH8.8-10.2, Most preferably, it is the range of pH9.0-10.0.

  When a combination of (a) carbonate ion and bicarbonate ion is employed as a pH buffer, the total amount of carbonate ion and bicarbonate ion is preferably 0.05 to 5 mol / L with respect to the total weight of the developer, 0.1-2 mol / L is more preferable, and 0.2-1 mol / L is particularly preferable. If the total amount is 0.05 mol / L or more, developability and processing capacity are not lowered, and if it is 5 mol / L or less, it becomes difficult to form precipitates and crystals, and further, during the waste liquid treatment of the developer, and during neutralization It becomes difficult to gel and does not interfere with waste liquid treatment.

Further, for the purpose of assisting the fine adjustment of the alkali concentration and the dissolution of the non-image area photosensitive layer, an alkali agent such as an organic alkali agent may be supplementarily used together.
Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These other alkaline agents are used alone or in combination of two or more.

  When (b) borate ions are employed as the pH buffering agent, the total amount of borate ions is preferably 0.05 to 5 mol / L, more preferably 0.1 to 2 mol / L, based on the total weight of the developer. 0.2 to 1 mol / L is particularly preferable. When the total amount of borate is 0.05 mol / L or more, developability and processing ability are not deteriorated. On the other hand, when it is 5 mol / L or less, it becomes difficult to form precipitates and crystals, and further, during the processing of waste liquid of the developer. It becomes difficult to gel during neutralization and does not interfere with waste liquid treatment.

  When (c) a water-soluble amine compound and ions of the amine compound are employed as the pH buffering agent, the total amount of the water-soluble amine compound and ions of the amine compound is 0.01 to the total weight of the developer. ˜1 mol / L is preferable, 0.03 to 0.7 mol / L is more preferable, and 0.05 to 0.5 mol / L is particularly preferable. When the pH is within the above range, developability and processing ability are not lowered, while waste liquid treatment is easy.

Specific examples of the developer having a buffering capacity include, but are not limited to, the following.
Maleic acid / trishydroxymethylaminomethane (Tris) / sodium hydroxide buffer, disodium hydrogen phosphate / sodium dihydrogen phosphate buffer, potassium dihydrogen phosphate / sodium hydroxide buffer, 2,4,6- Trimethylpyridine / hydrochloric acid buffer, triethanolamine hydrochloride / sodium hydroxide buffer, sodium 5,5-diethylbarbiturate / hydrochloric acid buffer, N-ethylmorpholine / hydrochloric acid buffer, sodium pyrophosphate / hydrochloric acid buffer, Tris / hydrochloric acid buffer, N, N-bis (2-hydroxyethyl) glycine (Bicine) / sodium hydroxide buffer, 2-amino-2-methylpropane-1,3-diol / hydrochloric acid buffer, diethanolamine / hydrochloric acid Buffer, potassium p-phenolsulfonate / sodium hydroxide buffer, boron / Sodium hydroxide buffer, sodium borate / hydrochloric acid buffer, ammonia / ammonium chloride buffer, glycine / sodium hydroxide buffer, sodium carbonate / sodium bicarbonate buffer, sodium borate / sodium hydroxide buffer, carbonic acid Sodium hydrogen / sodium hydroxide buffer, disodium hydrogen phosphate / sodium hydroxide buffer, sodium hydroxide / potassium chloride buffer, citric acid / disodium hydrogen phosphate buffer, piperazine dihydrochloride / glycylglycine / Examples include sodium hydroxide buffer, citric acid monohydrate / potassium dihydrogen phosphate / boric acid / diethyl barbituric acid / sodium hydroxide buffer, boric acid / citric acid / sodium phosphate dodecahydrate buffer. It is done.

  Among these, from the viewpoint of developability, sodium 5,5-diethylbarbiturate / hydrochloric acid buffer, Tris / hydrochloric acid buffer, 2-amino-2-methylpropane-1,3-diol / hydrochloric acid buffer, diethanolamine / Hydrochloric acid buffer, potassium p-phenolsulfonate / sodium hydroxide buffer, boric acid / sodium hydroxide buffer, sodium borate / hydrochloric acid buffer, ammonia / ammonium chloride buffer, glycine / sodium hydroxide buffer, Sodium carbonate / sodium bicarbonate buffer, sodium borate / sodium hydroxide buffer, sodium bicarbonate / sodium hydroxide buffer, disodium hydrogen phosphate / sodium hydroxide buffer, sodium hydroxide / potassium chloride buffer, Piperazine dihydrochloride / glycylglycine / sodium hydroxide buffer Citric acid monohydrate / potassium dihydrogen phosphate / boric acid / diethyl barbituric acid / sodium hydroxide buffer, boric acid / citric acid / sodium phosphate dodecahydrate buffer are preferred, and p-phenolsulfone Potassium / sodium hydroxide buffer, borate / sodium hydroxide buffer, ammonia / ammonium chloride buffer, glycine / sodium hydroxide buffer, sodium carbonate / sodium bicarbonate buffer, sodium borate / sodium hydroxide buffer Solution, sodium bicarbonate / sodium hydroxide buffer, disodium hydrogen phosphate / sodium hydroxide buffer, sodium hydroxide / potassium chloride buffer, piperazine dihydrochloride / glycylglycine / sodium hydroxide buffer, citric acid Monohydrate / potassium dihydrogen phosphate / boric acid / diethyl barbitur / Sodium hydroxide buffer, sodium borate / citrate / phosphate dodecahydrate buffer are more preferable.

The developer that can be used in the present invention preferably contains a surfactant.
The surfactant that can be used in the present invention may contain any of anionic, nonionic, cationic, and amphoteric.
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.

  The cationic surfactant is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  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, oil and fat 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.

  In the present invention, a polyethylene glycol type higher alcohol ethylene oxide adduct, an aromatic compound polyethylene glycol adduct, sorbitol and / or sorbitan fatty acid ester ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide More preferred are block copolymers, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymers, and fatty acid esters of polyhydric alcohols.

Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant preferably has an HLB (Hydrophile-Lipophile Balance) value of 6 or more, more preferably 8 or more. Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.
Surfactant can be used individually by 1 type or in combination of 2 or more types.
The content of the surfactant in the developer is preferably from 0.01 to 10% by weight, and more preferably from 0.01 to 5% by weight.

As is well known in the field of surfactants, amphoteric surfactants are compounds having an anionic moiety and a cationic moiety in the same molecule, and are amphoteric such as amino acids, betaines, and amine oxides. A surfactant is included.
As the amphoteric surfactant that can be used in the developer of the present invention, a compound represented by the following formula <1> and a compound represented by the following formula <2> are preferable.

In formula <1>, R ⁸ represents an alkyl group, R ⁹ and R ¹⁰ each independently represents a hydrogen atom or an alkyl group, R ¹¹ represents an alkylene group, and A represents a carboxylate ion or a sulfonate ion. To express.
In formula <2>, R ¹⁸ , R ¹⁹ and R ²⁰ each independently represents a hydrogen atom or an alkyl group. However, not all of R ¹⁸ , R ¹⁹ and R ²⁰ are hydrogen atoms.

In Formula <1>, the alkyl group for R ^8, R ⁹ or R ^10, and, the alkylene group for R ¹¹ may be linear or branched, and may have a linking group in the chain In addition, it may further have a substituent. As the linking group, those containing a hetero atom such as an ester bond, an amide bond, or an ether bond are preferable. Moreover, as a substituent, a hydroxyl group, an ethylene oxide group, a phenyl group, an amide group, a halogen atom, etc. are preferable.
In the compound represented by the formula <1>, the total number of carbon atoms of R ^{8 to} R 11 is preferably ^{8 to} 25, and more preferably 11 to 21. Within the above range, the hydrophobic portion is appropriate and the solubility in an aqueous developer is excellent.
It is also possible to increase the solubility of the surfactant in an aqueous developer by adding an organic solvent, for example, a solubilizing agent such as alcohol.

In the above formula <2>, the alkyl group in R ¹⁸ , R ¹⁹ or R ²⁰ may be linear or branched, may have a linking group in the chain, and further has a substituent. You may do it. As the linking group, those containing a hetero atom such as an ester bond, an amide bond, or an ether bond are preferable. Moreover, as a substituent, a hydroxyl group, an ethylene oxide group, a phenyl group, an amide group, a halogen atom, etc. are preferable.
In the compound represented by the formula <2>, the total number of carbon atoms of R ^{18 to} R ²⁰ is preferably 8 to 22, and more preferably 10 to 20. Within the above range, the hydrophobic portion is appropriate and the solubility in an aqueous developer is excellent.

  The total carbon number of the amphoteric surfactant may be affected by the material used for the photosensitive layer, particularly the properties of the binder. In the case of a binder having a high degree of hydrophilicity, those having a relatively small total carbon number are preferred, and when the binder used has a low degree of hydrophilicity, those having a large total carbon number tend to be preferred.

  Preferable specific examples of the amphoteric surfactant that can be used in the developer are shown below, but the present invention is not limited thereto.

  In addition to the above, the developer that can be used in the present invention may contain a wetting agent, preservative, chelate compound, antifoaming agent, organic solvent, inorganic acid, inorganic salt, water-soluble resin, and the like.

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

Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzoisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, benztriazole derivatives Amiding anidine derivatives, quaternary ammonium salts, pyridine, quinoline, guanidine and other derivatives, diazines, triazole derivatives, oxazoles, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diols, 1 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used. It is preferable to use two or more kinds of preservatives in combination so as to be effective against various molds and sterilization.
The addition amount of the preservative is an amount that stably exerts an effect on bacteria, mold, yeast, etc., and varies depending on the type of bacteria, mold, yeast, but 0.01 to A range of 4% by weight is preferred.

Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids such as phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.
As the chelating agent, one that is stably present in the composition of the treatment liquid and does not inhibit the printability is selected.
The addition amount of the chelating agent is preferably 0.001 to 1.0% by weight with respect to the developer.

As the antifoaming agent, a general silicone-based self-emulsifying type, emulsifying type, nonionic HLB 5 or less compound can be used. Among these, a silicone antifoaming agent is preferable.
Also, any antifoaming agent such as an emulsifying dispersion type and a solubilizing type can be used.
The content of the antifoaming agent is preferably in the range of 0.001 to 1.0% by weight with respect to the developer.

  Examples of the organic solvent include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (produced by Esso Chemical Co., Ltd.), gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.) ), Halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.) and polar solvents.

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

  When the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the developer contains an organic solvent, the concentration of the solvent is preferably less than 40% by weight from the viewpoints of safety and flammability.

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

Examples of water-soluble resins that can be incorporated into the developer include soybean polysaccharides, modified starches, gum arabic, dextrin, fiber derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol And derivatives thereof, polyvinylpyrrolidone, polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like.
Moreover, the preferable acid value of water-soluble resin is 0-3.0 meq / g.

  As the soybean polysaccharide, conventionally known ones can be used. For example, as a commercial product, there is Soya Five (manufactured by Fuji Oil Co., Ltd.), and various grades can be used. What can be preferably used is one in which the viscosity of a 10% by weight aqueous solution is in the range of 10 to 100 mPa / sec.

  Examples of modified starch include those represented by the following formula (III). As the starch represented by the formula (III), any starch such as corn, potato, tapioca, rice and wheat can be used. These starch modifications can be made by, for example, a method of decomposing within 5 to 30 glucose residues per molecule with an acid or enzyme, and further adding oxypropylene in an alkali.

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

  Examples of modified starch and derivatives thereof include roasted starch such as British gum, enzyme modified dextrin such as enzyme dextrin and shardinger dextrin, oxidized starch shown in solubilized starch, modified pregelatinized starch and unmodified pregelatinized starch Alpha starch, phosphate starch, fat starch, sulfate starch, nitrate starch, xanthate starch, carbamic acid starch and other esterified starch, carboxyalkyl starch, hydroxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch , Etherified starch such as carbamylethyl starch and dialkylamino starch, methylol cross-linked starch, hydroxyalkyl cross-linked starch, phosphate cross-linked starch, dicarboxylic acid cross-linked starch and other cross-linked starch, starch polyacrylamide copolymer, starch polyacrylic acid co Polymer Starch polyvinyl acetate copolymer, starch polyacrylonitrile copolymer, chaotic starch polyacrylic ester copolymer, chaotic starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer, There are starch graft polymers such as starch polypropylene copolymer.

Among the water-soluble resins, preferred are soy polysaccharides, modified starches, gum arabic, dextrin, carboxymethyl cellulose, polyvinyl alcohol and the like.
Two or more water-soluble resins can be used in combination.
The content of the water-soluble resin in the treatment liquid is preferably 0.1 to 20% by weight, and more preferably 0.5 to 10% by weight.

  The temperature for development is preferably 60 ° C. or less, more preferably about 15 to 40 ° C. 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.

After the development step is performed, the developer may be dried by natural drying, but it is preferable to provide a drying step with warm air or the like.
In the method for producing a lithographic printing plate of the present invention, the entire surface may be heated between exposure and development, if necessary. By such heating, an image forming reaction in the image recording layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur.

The heating conditions can be appropriately set within the range where these effects are present.
Examples of the heating means include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. For example, it can be carried out by holding the plate surface temperature in the range of 70 to 150 ° C. for 1 second to 5 minutes. Preferably, the temperature is 80 ° C to 140 ° C for 5 to 1 minute, more preferably 90 ° C to 130 ° C for 10 to 30 seconds. This range is preferable in that the above effect can be obtained efficiently and there is no adverse effect such as deformation of the printing plate due to heat.
The heat treatment means used for the heat treatment is preferably connected to a plate setter used in the exposure process and a developing device used in the development process, and automatically and continuously processed. Specifically, there is a plate making line in which a plate setter and a developing device are coupled by a conveying means such as a conveyor. A heat treatment means may be provided between the plate setter and the developing device, and the heating means and the developing device may be integrated.

When the lithographic printing plate precursor to be used is easily affected by ambient light in the working environment, the plate making line is preferably shielded from light by a filter or a cover.
Further, the entire surface of the printing plate after development may be exposed with an actinic ray such as ultraviolet light to accelerate the curing of the image area. Examples of the light source for the entire surface exposure include a carbon arc lamp, a mercury lamp, a gallium lamp, a metal halide lamp, a xenon lamp, a tungsten lamp, and various laser lights. Order to obtain sufficient printing durability, the exposure is preferably 10 mJ / cm ² or more, 100 mJ / cm ² or more is more preferable.
Heating may be performed simultaneously with the entire surface exposure, and further improvement in printing durability is recognized by heating. Examples of the heating device include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like.
At this time, the plate surface temperature is preferably 30 ° C to 150 ° C, more preferably 35 ° C to 130 ° C, and further preferably 40 ° C to 120 ° C. Specifically, the method described in JP 2000-89478 A can be used.
Further, for the purpose of improving printing durability, the developed printing plate can be heated under very strong conditions. The heating temperature is preferably in the range of 200 to 500 ° C. Within the above range, a sufficient image strengthening action can be obtained, and problems such as deterioration of the support and thermal decomposition of the image portion can be prevented.
The lithographic printing plate thus obtained can be loaded on an offset printing machine and used for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

<Examples 1-36 and Comparative Examples 1-3>
[Production of support]
The following surface treatment was performed using an aluminum plate (JIS A1050) having a thickness of 0.03 mm.
(A) Mechanical surface roughening treatment While supplying a suspension of a polishing agent (pumice) having a specific gravity of 1.12 and water as a polishing slurry liquid to the surface of the aluminum plate, mechanical roughening is performed by a rotating nylon brush. Surface treatment was performed. The average particle size of the abrasive was 30 μm, and the maximum particle size was 100 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 45 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 was etched by spraying using an aqueous solution having a caustic soda concentration of 2.6% by weight, an aluminum ion concentration of 6.5% by weight and a temperature of 70 ° C., thereby dissolving the aluminum plate by 10 g / m ² . . Then, water washing by spraying was performed.

(C) Desmutting treatment Desmutting treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. As the nitric acid aqueous solution used for the desmut treatment, the waste liquid of the step of performing an electrochemical surface roughening treatment using alternating current in the following nitric acid aqueous solution was used.

(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 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by weight of ammonium ions) at a liquid temperature of 50 ° C. An electrochemical surface roughening treatment was performed 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 and a duty ratio of 1: 1. 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. Then, water washing by spraying was performed.

(E) Alkaline etching treatment The aluminum plate was subjected to an etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26% by weight and an aluminum ion concentration of 6.5% by weight to dissolve the aluminum plate by 0.50 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid having a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a 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 5.0 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. An electrochemical surface roughening treatment was performed 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 and a duty ratio of 1: 1. 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. Then, water washing by spraying was performed.

(H) Anodizing treatment Anodizing device of two-stage feeding electrolytic treatment method (first and second electrolytic section length 6 m each, first and second feeding section length 3 m each, first and second feeding electrode section length 2.4 m each) Anodizing was performed using this. The electrolytes supplied to the first and second electrolysis sections both had a sulfuric acid concentration of 50 g / L (containing 0.5% by weight of aluminum ions) and a temperature of 20 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .

The aluminum plate which performed all the said (a)-(h) process is the support body 1, The aluminum plate which implemented only the process (d)-(h) is the support body 2, (d)-(f) and (h). The aluminum plate which performed only the process was used as the support body 3. When the center line average roughness (Ra indication according to JIS B0601) of each support was measured using a needle having a diameter of 2 μm, the support 1 was 0.52 μm, the support 2 was 0.28 μm, and the support 3 was 0.3. It was 25 μm.
Further, the supports 1 to 3 were immersed in a 40 ° C. aqueous solution containing 4 g / L of polyvinylphosphonic acid for 10 seconds, washed with 20 ° C. tap water for 2 seconds, and dried to give the undercoat layer 1. Supports 4 to 6 were prepared.

[Formation of photosensitive layer]
A photosensitive layer coating solution 1 having the following composition was bar coated on the aluminum support provided with the undercoat layer 1 and then oven-dried at 70 ° C. for 60 seconds to form a photosensitive layer having a dry coating amount of 1.1 g / m ^2. A protective layer coating solution 1 having the following composition is formed on the coating layer using a bar so that the dry coating amount is 0.75 g / m ^2, and then dried at 125 ° C. for 70 seconds for protection. A layer was formed to prepare a lithographic printing plate precursor.

(Photosensitive layer coating solution 1)
Binder polymer (B-1) 0.52 parts by weight Compound having an ethylenically unsaturated bond (Exemplary compounds described in Table 9) x parts by weight Compound having an ethylenically unsaturated bond (M-1) (0. 50-x) parts by weight-radical polymerization initiator (I-1) 0.08 parts by weight-sensitizing dye (D-1) 0.06 parts by weight-chain transfer agent (S-2) 0.07 parts by weight- ε-phthalocyanine pigment dispersion 0.40 part by weight (pigment: 15 parts by weight, allyl methacrylate / methacrylic acid (80/20) copolymer as dispersant: 10 parts by weight, cyclohexanone / methoxypropyl acetate / 1- (Methoxy-2-propanol = 15 parts by weight / 20 parts by weight / 40 parts by weight)
・ 0.01 parts by weight of thermal polymerization inhibitor (N-nitrosophenylhydroxylamine aluminum salt)
-0.001 part by weight of fluorosurfactant (Megafac F-780-F, Dainippon Ink & Chemicals, Inc., 30% by weight methyl isobutyl ketone (MIBK) solution)
-Polyoxyethylene-polyoxypropylene condensate 0.04 parts by weight (Asahi Denka Kogyo Co., Ltd., Pluronic L44)
-1-methoxy-2-propanol 3.5 parts by weight-Methyl ethyl ketone 8.0 parts by weight

[Formation of protective layer]
(Protective layer coating solution)
On the photosensitive layer, a protective layer coating solution having the following composition was bar-coated, followed by oven drying at 125 ° C. for 70 seconds to form a protective layer having a dry coating amount of 1.25 g / m ² .
(Protective layer coating solution)
-0.6 part by weight of the following mica dispersion-0.8 part by weight of sulfonic acid-modified polyvinyl alcohol (Goselan CKS-50, manufactured by Nippon Synthetic Chemical Co., Ltd. (degree of saponification: 99 mol%, average degree of polymerization: 300, modified) Degree: about 0.4 mol%))
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (molecular weight: 70,000)
0.001 part by weight / surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.002 part by weight / water 13 part by weight

(Mica dispersion)
To 368 parts by weight of water, 32 parts by weight of synthetic mica (Somasif ME-100, manufactured by Coop Chemical Co., Ltd., aspect ratio: 1,000 or more) was added, and the average particle size (laser scattering method) 0.5 μm using a homogenizer. To obtain a mica dispersion.

[Exposure, development and printing]
Each of the lithographic printing plate precursors was image-exposed with a FFEI Violet semiconductor laser plate setter Vx9600 (equipped with an InGaN-based semiconductor laser (with an emission wavelength of 405 nm ± 10 nm / output 30 mW)). The image was drawn at a resolution of 2,438 dpi using an FM screen (TAFFETA 20) manufactured by FUJIFILM Corporation with a plate surface exposure of 0.05 mJ / cm ² .
Next, after preheating at 100 ° C. for 30 seconds, development processing was performed with an automatic developing processor having a structure as shown in FIG. The automatic processor has one brush roll with an outer diameter of 50 mm in which fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 17 mm) are implanted, and rotates 200 times per minute in the same direction as the conveying direction ( The peripheral speed of the brush tip was 0.52 m / sec). The temperature of the treatment liquid was 30 ° C. The planographic printing plate precursor was transported at a transport speed of 100 cm / min. After the development processing, drying was performed in a drying section. The drying temperature was 80 ° C.

  Tables 1 to 8 below show the compositions of Developers 1 to 8 used in Examples or Comparative Examples. The following New Coal B13 (Nippon Emulsifier Co., Ltd.) is polyoxyethylene β-naphthyl ether (oxyethylene average number n = 13).

  The obtained lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and fountain solution (EU-3 (etch solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio). )) And TRANS-G (N) black ink (Dainippon Ink Chemical Co., Ltd.) were used for printing at a printing speed of 6,000 sheets per hour.

[Evaluation]
The resulting lithographic printing plate was used to evaluate developability, sensitivity, printing durability, stain resistance, and development residue as follows.

<Developability>
Development was carried out at various conveying speeds as described above, and the cyan density of the non-image area was measured with a Macbeth densitometer. The transport speed at which the cyan density of the non-image area was equal to the cyan density of the aluminum substrate was determined and defined as developability.
The evaluation of developability is represented by the relative developability defined as follows using Comparative Example 1 as a reference (1.0). A larger relative developability value indicates higher developability and better performance.
Relative developability = (target photosensitive material transport speed) / (reference photosensitive material transport speed)

<Sensitivity>
The coated and dried lithographic printing plate precursor was exposed by changing the exposure amount of the plate surface. After 100 sheets were printed as described above and it was confirmed that a printed matter having no ink stains in the non-image area was obtained, 500 sheets were printed continuously. In the total 600th printed matter, the exposure amount with no unevenness in the ink density in the image area was measured as sensitivity.
Sensitivity evaluation is represented by the relative sensitivity defined as follows using Comparative Example 1 as a reference (1.0). The larger the relative sensitivity value, the higher the sensitivity and the better the performance.
Relative sensitivity = (sensitivity of standard photosensitive material / sensitivity of target photosensitive material)

<Print durability>
As the number of printed sheets was increased, the photosensitive layer was gradually worn out and the ink acceptability was lowered, so that the ink density in the printing paper was lowered. In the printing plate exposed with the same exposure amount, the printing durability was evaluated by the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing.
The evaluation of printing durability is represented by the relative printing durability defined as follows using Comparative Example 1 as a reference (1.0). The larger the relative printing durability number, the higher the printing durability.
Relative printing durability = (printing durability of target photosensitive material) / (printing durability of standard photosensitive material)

<Reproducibility of halftone dots>
As described above, 1,000 sheets were printed and the halftone dot (small dot) area on the planographic printing plate was not reduced at all. A triangle mark indicates that a halftone dot area is reduced and has a practical problem.

<Development residue>
If the lithographic printing plate precursor has a photosensitive layer or a protective layer, 0.4 g of the photosensitive layer and protective layer are scraped and dispersed in 10 mL of developer (when a lithographic printing plate precursor of 20 m ² per liter is developed) The amount of the photosensitive layer (and the protective layer) dissolved in the developer was visually observed for residue in the developer when stored at 30 ° C. for 1 week. "◎" for uniform dispersions, "○" for inferior to "◎" but no problem for practical use, "△" for turbid components with practical problems, causing precipitation Things are represented as “x”.

  Table 9 below shows the evaluation results of Examples 1-36 and Comparative Examples 1-3.

As shown in Table 9, by introducing a specific ethylenically unsaturated compound into the photosensitive layer, the developability can be improved while maintaining the sensitivity and printing durability, and the halftone dot reproducibility is also improved. I understand that Further, an excellent improvement effect was obtained with respect to development residue.
Moreover, it turns out that a methacryloyl group (group represented by Formula (A)) is the most preferable from a viewpoint of a sensitivity and printing durability. Furthermore, as described above, it can be seen that a compound containing a urethane skeleton in the molecule is preferable from the viewpoints of sensitivity and printing durability.
In addition, when Example 35 and Example 36 were compared with Example 14, it was better in terms of developability to use a developer having a buffer capacity.

<Examples 37 to 63 and Comparative Examples 4 to 6>
[Production of support]
A support was produced in the same manner as in Example 1.

[Formation of photosensitive layer]
A photosensitive layer coating solution 1 having the following composition was bar-coated on the aluminum support provided with the undercoat layer, followed by oven drying at 90 ° C. for 60 seconds to form a photosensitive layer having a dry coating amount of 1.1 g / m ^2. A protective layer coating solution 1 having the following composition is formed on the coating layer using a bar so that the dry coating amount is 0.75 g / m ^2, and then dried at 125 ° C. for 70 seconds for protection. A layer was formed to prepare a lithographic printing plate precursor.

(Photosensitive layer coating solution 2)
Binder polymer (B-2) 0.52 parts by weight Compound having an ethylenically unsaturated bond (Exemplary compounds described in Table 10) x part by weight Compound having an ethylenically unsaturated bond (M-1) (0. 50-x) parts by weight-radical polymerization initiator (I-1) 0.08 parts by weight-sensitizing dye (D-1) 0.06 parts by weight-chain transfer agent (S-2) 0.07 parts by weight- ε-phthalocyanine pigment dispersion 0.40 part by weight (pigment: 15 parts by weight, allyl methacrylate / methacrylic acid (80/20) copolymer as dispersant: 10 parts by weight, cyclohexanone / methoxypropyl acetate / 1- (Methoxy-2-propanol = 15 parts by weight / 20 parts by weight / 40 parts by weight)
・ 0.01 parts by weight of thermal polymerization inhibitor (N-nitrosophenylhydroxylamine aluminum salt)
-0.001 part by weight of fluorosurfactant (Megafac F-780-F, Dainippon Ink & Chemicals, Inc., 30% by weight methyl isobutyl ketone (MIBK) solution)
-Polyoxyethylene-polyoxypropylene condensate 0.04 parts by weight (Asahi Denka Kogyo Co., Ltd., Pluronic L44)
-1-methoxy-2-propanol 3.5 parts by weight-Methyl ethyl ketone 8.0 parts by weight

  The photosensitive layer components other than the binder polymer (B-2) are the same as in Example 1.

[Formation of protective layer]
A protective layer was produced in the same manner as in Example 1.

[Exposure, development and printing]
Exposure, development, and printing were performed in the same manner as in Example 1.

[Evaluation]
Using the obtained lithographic printing plate, developability, sensitivity, printing durability, halftone dot reproducibility, and development residue were evaluated in the same manner as in Example 1.

  The evaluation results of Examples 37 to 63 and Comparative Examples 4 to 6 are shown in Table 10 below.

As shown in Table 10, by introducing a specific ethylenically unsaturated compound into the photosensitive layer, developability can be improved while maintaining sensitivity and printing durability, and dot reproducibility is also improved. I understand that Further, an excellent improvement effect was obtained with respect to development residue.
Moreover, it turns out that a methacryloyl group (group represented by Formula (A)) is the most preferable from a viewpoint of a sensitivity and printing durability. Furthermore, as described above, it can be seen that a compound containing a urethane skeleton in the molecule is preferable from the viewpoints of sensitivity and printing durability.
In addition, when Example 62 and Example 63 were compared with Example 47, it was better in terms of developability to use a developer having a buffering capacity.

<Examples 64-99 and Comparative Examples 7-9>
[Production of support]
A support was produced in the same manner as in Example 1.

[Formation of photosensitive layer]
The following photosensitive layer coating solution 3 was prepared and coated on the support formed as described above using a wire bar. Drying was performed for 60 seconds at 100 ° C. with a warm air dryer. The coating amount after drying was 1.4 g / m ² .

(Photosensitive layer coating solution 3)
Infrared absorber (IR-1) 0.030 parts by weight Polymerization initiator A (I-2) 0.069 parts by weight Polymerization initiator B (I-3) 0.094 parts by weight Mercapto compound (E- 1) 0.020 part by weight / ethylenically unsaturated compound (exemplary compounds described in Table 11) x part by weight / ethylenically unsaturated compound (M-2) (0.425-x) part by weight (trade name: A- BPE-4, Shin-Nakamura Chemical Co., Ltd.)
Binder polymer A (B-3) 0.250 parts by weight Binder polymer B (B-4) 0.200 parts by weight Binder polymer C (B-5) 0.150 parts by weight Additive (T-1) 0.080 parts by weight-polymerization inhibitor (Q-1) 0.0012 parts by weight-ethyl violet (EV-1) 0.021 parts by weight-fluorine-based surfactant 0.0081 parts by weight (Megafac F-780- F, Dai Nippon Ink Chemical Co., Ltd., methyl isobutyl ketone (MIBK) 30% by weight solution)
-Methyl ethyl ketone 5.886 parts by weight-Methanol 2.733 parts by weight-1-methoxy-2-propanol 5.886 parts by weight In addition, the infrared absorber (IR-1) used for the photosensitive layer coating solution 3 and polymerization initiation Agent A (I-2), Polymerization Initiator B (I-3), Mercapto Compound (E-1), Polymerizable Compound (M-2), Binder Polymer A (B-3), Binder Polymer B (B- 4) The structure of binder polymer C (B-5), additive (T-1), polymerization inhibitor (Q-1), and ethyl violet (EV-1) is shown below.

  The weight average molecular weight of the binder polymer (B-3) was 100,000, and the weight average molecular weight of the binder polymer (B-4) was 110,000.

  The weight average molecular weight of the binder polymer (B-5) was 120,000.

[Formation of protective layer]
A protective layer was formed in the same manner as in Example 1.

[Exposure, development and printing]
The obtained lithographic printing plate precursor was processed in the order of steps of exposure, development, and drying.
Light source (setter) used for exposure: Image-like exposure was performed with an infrared semiconductor laser (Trendsetter 3244VX manufactured by Creo) equipped with a water-cooled 40W infrared semiconductor laser, with an output of 9 W, an outer drum rotation speed of 210 rpm, and a resolution of 2,400 dpi. It was. Next, after preheating at 100 ° C. for 30 seconds within 30 seconds, each of the above-described developing solutions was used and development processing was performed in the automatic development processing apparatus having the structure shown in FIG. .
The obtained lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and fountain solution (EU-3 (etch solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio). )) And TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), printing was performed at a printing speed of 6,000 sheets per hour.

[Evaluation]
Using the obtained lithographic printing plate, developability, sensitivity, printing durability, halftone dot reproducibility, and development residue were evaluated in the same manner as in Example 1.

  Table 11 below shows the evaluation results of Examples 64-99 and Comparative Examples 7-9.

As shown in Table 11, by introducing a specific ethylenically unsaturated compound into the photosensitive layer, for those containing a methacryloyl group in the structure, the developability can be improved while maintaining the sensitivity and printing durability. It can also be seen that the halftone dot reproducibility is also improved. Further, an excellent improvement effect was obtained with respect to development residue.
Moreover, it turns out that a methacryloyl group (group represented by Formula (A)) is the most preferable from a viewpoint of a sensitivity and printing durability. Furthermore, as described above, it can be seen that a compound containing a urethane skeleton in the molecule is preferable from the viewpoints of sensitivity and printing durability.
In addition, when Example 98 and Example 99 were compared with Example 77, it was better in terms of developability to use a developer having a buffer capacity.

It is explanatory drawing which shows the structure of an automatic developing processor.

Explanation of symbols

4 Planographic printing plate precursor 6 Developing unit 10 Drying unit 16 Transport roller 20 Developing tank 22 Transport roller 24 Brush roller 26 Squeeze roller 28 Backup roller 36 Guide roller 38 Skewer roller

Claims (11)

On the support, there is a photosensitive layer containing (i) a binder polymer, (ii) an ethylenically unsaturated compound, and (iii) a polymerization initiator,
The lithographic printing plate precursor, wherein the (ii) ethylenically unsaturated compound contains a compound represented by the following formula (1):

(In formula (1), L represents a (m + n) -valent linking group, D represents a group selected from the group consisting of groups represented by the following formulas (A) to (D), and m is 1 or more. And n represents an integer of 2 or more.)

(In the formulas (A) to (D), X, Y and Z each independently represent an oxygen atom, a sulfur atom or NR ¹⁷ , and R ^{4 to} R ¹⁴ and R ¹⁷ each independently represent a hydrogen atom or a monovalent group. R ¹⁵ represents a hydrogen atom or a methyl group, R ¹⁶ represents a monovalent substituent, and k represents an integer of 0 to 4.)   The lithographic printing plate precursor according to claim 1, wherein D in the formula (1) is a group represented by the formula (A).   The lithographic printing plate precursor according to claim 1 or 2, wherein L in the formula (1) is a group having an ether bond, an ester bond, a urethane bond, a thiourethane bond, and / or a urea bond.   The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein L in the formula (1) is a group having a urethane bond, a thiourethane bond, and / or a urea bond. An exposure step for image exposure of the lithographic printing plate precursor according to any one of claims 1 to 4, and
A method for producing a lithographic printing plate, comprising a developing step of removing a photosensitive layer in a non-exposed portion in the presence of a developer having a buffering ability.   6. The method for producing a lithographic printing plate according to claim 5, wherein the pH of the developer having a buffer capacity is 7.5 to 11.0.   The developer having the buffering capacity includes (a) a combination of carbonate ions and hydrogen carbonate ions, (b) a borate ion, or (c) a combination of water-soluble amine compounds and ions of the amine compounds. The method for producing a lithographic printing plate according to claim 5 or 6.   The method for producing a lithographic printing plate according to any one of claims 5 to 7, wherein the developer having a buffering capacity is (a) a developer containing a combination of carbonate ions and hydrogen carbonate ions.   The method for producing a lithographic printing plate according to any one of claims 5 to 8, wherein the developer having a buffering capacity contains a water-soluble polymer compound.   The method for producing a lithographic printing plate according to any one of claims 5 to 9, wherein the developing step is a step of removing the photosensitive layer in the non-exposed area and performing gumming treatment with one solution.   The method for producing a lithographic printing plate according to any one of claims 5 to 10, wherein a washing step is not performed before and after the development step.

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