JP2009145592A - Lithographic printing plate precursor and plate making method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing plate precursor which can perform image recording with a laser and can suppress spot-like print stain while retaining adequate developability in a developer having pH of 3-9. <P>SOLUTION: The lithographic printing plate precursor has an undercoat layer and an image recording layer on a support and is developable with a developer having pH of 3-9, wherein the undercoat layer and/or the image recording layer contains a compound having a structure represented by general formula (1), and the compound preferably has a polyoxyethylene group or a polyoxypropylene group, wherein X<SP>+</SP><SB>1</SB>and X<SP>+</SP><SB>2</SB>each represent H<SP>+</SP>or a monovalent cationic group, and X<SP>+</SP><SB>1</SB>and X<SP>+</SP><SB>2</SB>together may represent a divalent cationic group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor. More specifically, the present invention relates to a lithographic printing plate precursor capable of image recording with a laser and capable of being developed with a developer having a pH of 3 to 9, and a plate making method thereof.

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 utilizes the property that water and oil-based inks 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, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, after exposing the lithographic printing plate precursor through an original image such as a lithographic film, the image recording layer corresponding to the image portion remains, and the unnecessary image recording layer corresponding to the non-image portion is removed with an alkaline developer. Alternatively, the lithographic printing plate is obtained by dissolving and removing with an organic solvent-containing developer and exposing the surface of the hydrophilic support to form a non-image portion to form a non-image portion.

  In the conventional plate-making process of a lithographic printing plate precursor, a process of dissolving and removing unnecessary image recording layers with a developer or the like is necessary after exposure, but simplifies such additional wet processing. This is one of the issues. In particular, in recent years, disposal of waste liquids discharged with high pH alkaline development processing has become a major concern for the entire industry due to consideration for the global environment. It is strongly desired that it can be developed.

  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 technology for manufacturing is attracting attention. Therefore, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

  From the background as described above, the adaptation to both the digitization and the simplification of the plate making work is now more strongly desired than ever before. In order to perform such digitized and simplified plate making work in a bright room or under a yellow light with good work efficiency, a light source and a lithographic printing plate precursor corresponding to the light source are required.

As such a laser light source, a solid-state laser such as a semiconductor laser that emits infrared light having a wavelength of 760 to 1200 nm and a YAG laser is extremely useful because a high-power and small-sized laser can be obtained at low cost. . A UV laser can also be used.

Further, as a lithographic printing plate precursor and a plate making method corresponding thereto, for example, Patent Document 1 discloses that an image forming layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder is provided on a hydrophilic support. Describes a plate making method in which the lithographic printing plate precursor provided in 1 is developed with a gum solution. In this plate making method, the lithographic printing plate precursor is subjected to image exposure using an infrared laser to form an image by fusing hydrophobic thermoplastic polymer particles, and then the unexposed portion is removed with a gum solution. Can be developed.
However, the method of forming an image by merging the fine particles by simple thermal fusion as described above has a problem that the image strength is extremely weak and the printing durability is insufficient, although it exhibits good developability. .

  Patent Document 2 contains (i) a hydrophilic support, and (ii) a radical polymerizable ethylenically unsaturated monomer, a radical polymerization initiator and an infrared absorbing dye, which is cured by infrared laser exposure, A lithographic printing plate precursor comprising a photosensitive layer that can be developed in step 1 is prepared, exposed imagewise with an infrared laser, and an uncured portion of the photosensitive layer is removed with a gum solution. Are listed. Patent Documents 3 and 4 describe a method for developing a lithographic printing plate precursor in which a radical polymerization type photosensitive layer is cured by infrared laser exposure and an unexposed portion is removed with an aqueous developer having a pH of 2 to 10.

The method using such a polymerization reaction has a feature that the image strength is relatively good because the chemical bond density of the image portion is higher than that of the image portion formed by thermal fusion of the polymer fine particles. .
However, in order to impart developability with a developing solution having a pH close to neutral, such as a gum solution, using a polymerization reaction, it is necessary to hydrophilize the image recording layer of the lithographic printing plate precursor. Corrosion of the support is accelerated, and there is a problem that dot-like (spot-like) printing stains occur when the lithographic printing plate precursor is stored for a long time. By making the image recording layer hydrophobic, the above-mentioned spot-like printing stains are improved, but developability is lowered. Thus, until now, image recording layer designs that balance the two have been made, but performance that satisfies both has not been obtained.
European Patent No. 1342568 International Publication No. 05/111727 Pamphlet US Pat. No. 6,902,865 JP 2006-106700 A

  Accordingly, an object of the present invention is to provide a lithographic printing plate precursor and a plate making method in which pot-like printing stains are suppressed while maintaining sufficient developability for a pH 3 to 9 developer.

1. A lithographic printing plate precursor having an undercoat layer and an image recording layer on a support and developable with a developer having a pH of 3 to 9, wherein the undercoat layer and / or the image recording layer is represented by the following general formula (1) A lithographic printing plate precursor comprising a compound represented by:

Here, X ⁺ ₁ and X ⁺ ₂ may be the same or different and represent H ⁺ or a monovalent cationic group. Instead of X ⁺ ₁ and X ⁺ ₂ , one divalent cationic group may be used.

2. 2. The lithographic printing plate precursor as described in 1 above, wherein the developer is a gum solution.
3. 3. The lithographic printing plate precursor as described in 1 or 2 above, wherein the compound having the structure represented by the general formula (1) described in 1 has a polyoxyethylene group or a polyoxypropylene group in the molecule.
4). The lithographic printing according to any one of 1 to 3, wherein the image recording layer contains (A) an infrared absorber, (B) a polymerization initiator, and (C) a polymerizable compound. Version original edition.
5). 5. The lithographic printing plate precursor as described in any one of 1 to 4 above, wherein the image recording layer contains microcapsules and / or microgels.
6). 4. The lithographic printing plate precursor as described in any one of 1 to 3, wherein the image recording layer contains (A) an infrared absorber and (D) a hydrophobized precursor.
7). A lithographic printing plate precursor as described in any one of 1 to 6 above, after imagewise exposure with an infrared laser, and then development with a developer having a pH of 3 to 9.
8). 8. The plate making method as described in 7 above, wherein the developer is a gum solution.

In the present invention, the problem can be solved by including a compound having a specific structure in the undercoat layer and / or the image recording layer.
Although the mechanism of action of the present invention is not clear, the cause of the spot-like printing stain is that the aluminum support is locally corroded during the storage time of the lithographic printing plate precursor, and the polymerization initiator in the image recording layer near the corroded portion. Is decomposed and the release of electrons from dissimilar metals in the aluminum support causes “dark polymerization” in which the polymerizable compound is locally polymerized, and the dark polymerized portion remains on the support even after development. There is. Since the compound of the present invention has chain transfer properties and lowers curability, it is considered that even if a corrosion residual film occurs, it can be removed at the time of development and no spot-like print stains are generated. In addition, when the compound of the present invention has a polyoxyethylene group or a polyoxypropylene group, the curability is further reduced by the chain transferability of this skeleton, so that the pot-like printing stain is not more generated. it is conceivable that. In addition, polyoxyethylene compounds and polyoxypropylene compounds have poor hydrophilicity and thus developability is deteriorated. However, since the compound of the present invention has an acid group salt in the molecule, sufficient water permeability is obtained and good. It is thought that a good developability was maintained.

  According to the present invention, it is possible to provide a lithographic printing plate precursor capable of recording an image with a laser and suppressing pot-like printing stains while maintaining sufficient developability for a developer having a pH of 3 to 9.

[Lithographic printing plate precursor]
The lithographic printing plate precursor of the present invention is a lithographic printing plate precursor that has an undercoat layer and an image recording layer on a support and can be developed with a developer having a pH of 3 to 9, and the undercoat layer and / or the image recording layer Contains a compound represented by the general formula (1). In addition, the lithographic printing plate precursor according to the invention is preferably a protective layer on the image recording layer.

(Compound represented by the general formula (1))
Below, the compound represented by General formula (1) is demonstrated.

Here, X ⁺ ₁ and X ⁺ ₂ may be the same or different and represent H ⁺ or a monovalent cationic group. Instead of X ⁺ ₁ and X ⁺ ₂ , one divalent cationic group may be used.
Examples of the monovalent cationic group include inorganic cationic groups such as lithium cation, sodium cation and potassium cation, and organic cationic groups such as quaternary ammonium group and quaternary phosphonium group. Examples of the divalent cationic group include a cation having two organic cationic groups such as a quaternary ammonium group and a quaternary phosphonium group in the molecule, and a divalent inorganic cation such as magnesium ion and calcium ion. Can be mentioned.
Of these cationic groups, sodium ion is particularly preferable.

  Moreover, it is more preferable that the compound represented by the general formula (1) of the present invention has a polyoxyethylene group or a polyoxypropylene group in the molecule. 1-100 are preferable, as for the preferable number of repeating units of an oxyethylene unit or an oxypropylene unit, More preferably, it is between 2-80, More preferably, it is between 3-40. By having a polyoxyethylene group or a polyoxypropylene group, a pot-like printing smear suppression effect is improved. When the number of repeating units of oxyethylene units or oxypropylene units is larger than 100, the coating solution solubility is deteriorated.

The addition amount of the compound having the structure of the general formula (1) to the image recording layer is preferably 0.5% by mass or more and 20% by mass or less of the total solid content of the image recording layer. More preferably, they are 1 mass% or more and 10 mass% or less, More preferably, they are 2 mass% or more and 8 mass% or less.
The amount of the compound having the structure of the general formula (1) added to the undercoat layer is preferably 0.5% by mass or more and 100% by mass or less of the total solid content of the undercoat layer. More preferably, it is 1.0 mass% or more and 90 mass% or less, More preferably, it is 5.0 mass% or more and 50 mass% or less.
The compound having the structure of the general formula (1) may be contained in both the undercoat layer and the image recording layer.
Within this range, a lithographic printing plate precursor having good developability and suppressing pot-like printing stains can be obtained. These compounds may be used alone or in combination of two or more.

  Among the compounds having the structure of the general formula (1), a compound having the structure of the following general formula (2) is particularly preferable.

In the formula, R represents an alkyl group or an aryl group which may have a substituent. n represents an integer of 0 to 20. X ⁺ ₁ and ^{X +} ₂ is ^{X +} ₁ and ^{X +} ₂ synonymous of formula (1).
The alkyl group may be linear, branched or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and most preferably 1 to 12 carbon atoms. Specific examples include a methyl group, an ethyl group, a butyl group, a 2-ethylhexyl group, a cyclohexyl group, a decyl group, a dodecyl group, and a hexadecyl group. Examples of the substituent of the alkyl group include a fatty acid amide group having 20 or less carbon atoms and an alkoxy group.
Examples of the aryl group include a phenyl group, a butylphenyl group, an amylphenyl group, an octylphenyl group, and a nonylphenyl group.

The compound having the structure of the general formula (1) of the present invention may have two or more structures of the general formula (1). Specific examples include compounds in which a plurality of groups obtained by removing one hydrogen atom from R in the general formula (2) are bonded through a single bond or a linking group. The linking group is not particularly limited, and examples thereof include an alkylene group, an arylene group, a divalent or higher heterocyclic group, and a trivalent or higher hydrocarbon group.

  Specific examples of the compound having the structure of the general formula (1) of the present invention are illustrated below, but the present invention is not limited to these examples.

  In addition, the compound which has a structure of General formula (1) of this invention is compoundable by the known method as described in Unexamined-Japanese-Patent No. 2002-356597 etc., for example.

(Image recording layer)
The image recording layer used in the present invention is an image recording layer capable of forming an image by removing an unexposed portion with a developer having a pH of 3 to 9 after exposure. A typical image forming mechanism contained in the image recording layer includes (1) (A) an infrared absorber, (B) a polymerization initiator, and (C) a polymerizable compound, and utilizes a polymerization reaction. And (2) (A) an infrared absorber and (D) a hydrophobized precursor, and a hydrophobic region utilizing thermal fusion or thermal reaction of the hydrophobized precursor. Examples of forming (image part) can be given. Further, a mixture of the above two embodiments may be used. For example, (1) the polymerization type image recording layer may contain (D) a hydrophobized precursor, or (2) the hydrophobized precursor type may contain a polymerizable compound. Especially, the aspect of the polymerization type containing (A) infrared absorber, (B) polymerization initiator, and (C) polymeric compound is preferable.
Hereinafter, constituent components of the image recording layer other than the compound represented by the general formula (1) will be described in detail.

<(A) Infrared absorber>
When forming an image of the lithographic printing plate precursor according to the present invention using a laser emitting infrared rays of 760 to 1200 nm as a light source, it is usually essential to use an infrared absorber. The infrared absorber has a function of converting the absorbed infrared light into heat and a function of being excited by infrared light and transferring electrons and / or energy to a polymerization initiator (radical generator) described later. The infrared absorber used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 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.
Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, The methine dyes described in JP-A-58-181690 and JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, Naphthoquinone dyes described in JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, and the like, squarylium dyes described in JP-A-58-112792, and the like; And cyanine dyes described in British Patent No. 434,875.

In addition, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also suitable. ) Pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59- No. 41363, No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and Pyrlium compounds described in JP-A-59-216146. And pentamethine thiopyrylium salts described in US Pat. No. 4,283,475, and Japanese Patent Publication Nos. 5-13514 and 5-19702. Pyrylium compounds shown also preferably used. Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).
Other preferable examples of the infrared absorbing dye of the present invention include specific indolenine cyanine dyes described in JP-A-2002-278057 as exemplified below.

  Among these dyes, cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes are preferable. Further, cyanine dyes and indolenine cyanine dyes are preferable, and one particularly preferable example is a cyanine dye represented by the following general formula (i).

In formula (i), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group represented by the following structural formula. 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 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows a nitrogen atom, a sulfur atom, an oxygen atom, a halogen atom, and a selenium atom. R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, a substituted amino group and a halogen atom, X a ^_- is Z _a to be described later ^_- is the same definition.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. In view of storage stability of the recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Preferred substituents include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, an alkoxy group having 12 or less carbon atoms, a hydrocarbon group having 12 or less carbon atoms, and 12 carbon atoms. Most preferred are not more than alkoxy groups. Y ¹ and Y ^2, which may be the same or different, each represent a sulfur or carbon atom number of 12 or less a dialkyl methylene group. 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. Preferable substituents include an alkoxy group having 12 or less carbon atoms, a carboxyl group, and a sulfo group, and an alkoxy group having 12 or less carbon atoms is most preferable. 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. Z _a ⁻ represents a counter anion. However, when the cyanine dye represented by formula (i) has an anionic substituent in the structure thereof, Z _a is does not require charge neutralization ^- is not necessary. Preferred Z _a ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, from the storage stability of the recording layer coating solution. Tetrafluoroborate ion, hexafluorophosphate ion, and aryl sulfonate ion.

Specific examples of cyanine dyes represented by formula (i) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. Can do.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 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 Application of Metal Soap” (Shobobo), “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 range, good stability of the pigment dispersion in the image recording layer coating solution and good uniformity of the image recording 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 may be added to another image recording layer provided, but when preparing a negative lithographic printing plate precursor, The image recording layer is added so that the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm is in the range of 0.3 to 1.2 by the reflection measurement method. Preferably, it is the range of 0.4-1.1. Within this range, a uniform polymerization reaction in the depth direction of the image recording layer proceeds, and good film strength of the image area and adhesion to the support can be obtained.
The absorbance of the image recording layer can be adjusted by the amount of infrared absorber added to the image recording layer and the thickness of the image recording layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, an image recording layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is set to the optical density. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

<(B) Polymerization initiator>
The (B) polymerization initiator used in the present invention is a compound that generates radicals by light, heat, or both, and initiates and accelerates polymerization of the polymerizable compound (C). As the polymerization initiator that can be used in the present invention, a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, and the like can be used.
Examples of the polymerization initiator in the present invention include (a) an organic halide, (b) a carbonyl compound, (c) an azo polymerization initiator, (d) an organic peroxide, (e) a metallocene compound, (f) Azide compounds, (g) hexaarylbiimidazole compounds, (h) organoborate compounds, (i) disulfone compounds, (j) oxime ester compounds, (k) onium salt compounds.

(A) Specific examples of the organic halide include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, and Japanese Examined Patent Publication No. 46-4605. JP-A 48-36281, JP-A 55-32070, JP-A 60-239736, JP-A 61-169835, JP-A 61-16983
7, JP-A 62-58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, P. Examples include compounds described in Hutt “Journal of Heterocyclic Chemistry” 1 (No 3), (1970) ”, and particularly preferable examples include oxazole compounds substituted with a trihalomethyl group and s-triazine compounds.

  More preferred examples include s-triazine derivatives and oxadiazole derivatives to which at least one mono, di, or trihalogen-substituted methyl group is bonded. Specifically, for example, 2,4,6-tris (monochloromethyl) -s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -S-triazine, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6 -Bis (trichloromethyl) -s-triazine, 2- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl) -4,6- (Trichloromethyl) -s-triazine, 2- (p-bromophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-fluorophenyl) -4,6-bis (trichloromethyl) ) -S-triazine, 2- (p-trifluoromethylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2,6-dichlorophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (2,6-difluorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2,6-dibromophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (4-biphenylyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4'-chloro-4-biphenylyl) -4,6 Bis (trichloromethyl) -s-triazine, 2- (p-cyanophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-acetylphenyl) -4,6-bis (trichloromethyl) ) -S-triazine, 2- (p-ethoxycarbonylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-phenoxycarbonylphenyl) -4,6-bis (trichloromethyl)- s-triazine, 2- (p-methylsulfonylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-dimethylsulfoniumphenyl) -4,6-bis (trichloromethyl) -s- Triazine tetrafluoroborate, 2- (2,4-difluorophenyl) -4,6-bis (trichloromethyl) -s-tria Gin, 2- (p-diethoxyphosphorylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [4- (4-hydroxyphenylcarbonylamino) phenyl] -4,6-bis (trichloro) Methyl) -s-triazine, 2- [4- (p-methoxyphenyl) -1,3-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis ( Trichloromethyl) -s-triazine, 2- (p-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4, 6-bis (trichloro) Methyl) -s-triazine, 2- (p-tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bi (Trichloromethyl) -s-triazine, 2-phenylthio-4,6-bis (trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6 -Tris (dibromomethyl) -s-triazine, 2,4,6-tris (tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy -4,6-bis (tribromomethyl) -s-triazine, 2- (o-methoxystyryl) -5-trichloromethyl-1,3,4-oxadiazole, 2- (3,4-epoxystyryl) -5-trichloromethyl-1,3,4-oxadiazole, 2- [1-phenyl-2- (4-methoxyphenyl) vinyl] -5-trichloromethyl-1,3 4-oxadiazole, 2- (p-hydroxystyryl) -5-trichloromethyl-1,3,4-oxadiazole, 2- (3,4-dihydroxystyryl) -5-trichloromethyl-1,3 4-oxadiazole, 2- (pt-butoxystyryl) -5-trichloromethyl-1,3,4-oxadiazole and the like.

  (B) Examples of carbonyl compounds include benzophenone, Michler's ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2- Dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenylketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1-hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylphenol) E) Acetophenone derivatives such as ketone, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, Examples thereof include benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  (C) As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  (D) Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert -Butylperoxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5- Dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) Hexane, 2 5-Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydi Carbonate, dimethoxyisopropylperoxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butylperoxyacetate, tert-butylperoxypivalate, tert-butylperoxyneodecanoate, tert -Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ', 4,4'-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3', 4 4′-tetra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate ), Carbonyldi (t-hexylperoxydihydrogen diphthalate), and the like.

  (E) As metallocene compounds, JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705 Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1- , Di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl Di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-pen Fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoro Phen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3 4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluoro-3- (pyrrol-1-yl) phen-1-yl, Examples thereof include iron-arene complexes described in 304453 and JP-A-1-152109.

(F) Examples of the azide compound include 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.
(G) Examples of hexaarylbiimidazole compounds include JP-B-6-29285, U.S. Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. Various compounds described in the specification, specifically 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′-tetrakis (m-methoxyphenyl) biidazole, 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′- Examples include tetraphenylbiimidazole and 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole.

  (H) Examples of the organic borate compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188865, JP-A-9-188686, JP-A-9-188710, JP 2000-131837, JP 2002-107916, JP 2764769, JP 2002-116539, and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”. Organoboron salts described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, and organic boron oxosulfonium complexes described in JP-A-6-157563, JP-A-175554, JP-A-6-1755 No. 3, an organoboron iodonium complex, an organoboron phosphonium complex described in JP-A-9-188710, JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, Specific examples include organoboron transition metal coordination complexes such as JP-A-7-306527 and JP-A-7-292014.

  (I) Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.

  (J) Examples of oxime ester compounds include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, JP 2000-66385 A And the compounds described in JP-A-2000-80068. Specific examples thereof include compounds represented by the following structural formula.

  (K) Examples of the onium salt compounds include S.I. I. Schlesinger, Photogr. Sci. Eng. 18, 387 (1974), T .; S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055 and 4,069,056, phosphonium salts described in European Patent Nos. 104 and 143, U.S. Pat. Nos. 339,049 and 410,201, 2-150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297,442 U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013, 4,73 No. 4,444, 2,833,827, German Patent Nos. 2,904,626, 3,604,580, and 3,604,581, the sulfonium salts described in J . V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

In particular, the oxime ester compound, diazonium salt, iodonium salt, and sulfonium salt are preferable from the viewpoint of reactivity and stability. In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
Preferred onium salts for the present invention are onium salts represented by the following general formulas (RI-I) to (RI-III).

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 1 carbon atom. -12 alkenyl group, C1-C12 alkynyl group, C1-C12 aryl group, C1-C12 alkoxy group, C1-C12 aryloxy group, halogen atom, C1-C12 An alkylamino group, a dialkylamino group having 1 to 12 carbon atoms, an alkylamide group or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxyl group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, A C1-C12 thioaryl group is mentioned. Z ^11- represents a monovalent anion, a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, stability, Perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, and sulfinate ion are preferable from the viewpoint of the visibility of the printout image.

In 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 have 1 to 12 carbon atoms. An alkyl group, 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, a halogen atom An alkylamino group having 1 to 12 carbon atoms, a dialkylamino group having 1 to 12 carbon atoms, an alkylamide group or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxyl group, a cyano group, a sulfonyl group, and 1 carbon atom -12 thioalkyl group and C1-C12 thioaryl group are mentioned. Z ^21- represents a monovalent anion, which is a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, Perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of the visibility of the printout image.

In the formula (RI-III), R ³¹ , R ³² and R ³³ each independently represents an aryl group having 20 or less carbon atoms, an alkyl group, an alkenyl group or an alkynyl group which may have 1 to 6 substituents. In view of reactivity and stability, an aryl group is desirable. Preferred substituents are alkyl groups having 1 to 12 carbon atoms, alkenyl groups having 1 to 12 carbon atoms, alkynyl groups having 1 to 12 carbon atoms, aryl groups having 1 to 12 carbon atoms, alkoxy groups 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. Z ^31- represents a monovalent anion, which is a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, sulfate ion, Perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of the visibility of the printout image, and more preferable examples are described in JP-A-2001-343742. Carboxylate ions, particularly preferably the carboxylate ions described in JP-A No. 2002-148790.
Examples of onium salts that can be suitably used as polymerization initiators in the present invention will be given below, but the present invention is not limited to these.

(B) The polymerization initiator is not limited to the above, but in particular, from the viewpoint of reactivity and stability, (a) an organic halide, in particular, a triazine-based initiator included therein, (j) an oxime ester More preferred are the compounds, (k) diazonium salts, iodonium salts and sulfonium salts included in the onium salt compounds. Among these polymerization initiators, from the viewpoint of improving the visibility of the printout image in combination with an infrared absorber, the onium salt is an inorganic anion such as PF ₆ ⁻ or BF ₄ ⁻ as a counter ion. Etc. are preferred. Furthermore, diaryliodonium is preferred as the onium salt because of its excellent color development.

These (B) polymerization initiators may be added to the same layer as the other components, or another layer may be provided in the image recording layer or adjacent thereto and added thereto.
These polymerization initiators are each preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content constituting the image recording layer. Can be added at a ratio of Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more.

<(C) Polymerizable compound>
The polymerizable compound (C) that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one terminal ethylenically unsaturated bond, preferably two or more. It is chosen from the compound which has. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer, isocyanuric acid EO There are modified triacrylates 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, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

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.

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

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

  Further, urethane-based addition polymerizable compounds produced using an addition reaction of isocyanate and hydroxyl group are also suitable. Specific examples of such compounds are described in, for example, Japanese Patent Publication No. 48-41708. Containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (A) to a polyisocyanate compound having two or more isocyanate groups in the molecule A vinyl urethane compound etc. are mentioned.

^{_{CH 2 = C (R 4)}} COOCH 2 CH (R 5) OH (A)
(However, R ⁴ and R ⁵ represent H or CH _3. )

  Further, urethane acrylates as described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 And urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418. Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and acrylic acid or methacrylic acid described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-B-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, specific unsaturated compounds described in each gazette, vinylphosphonic acid compounds described in JP-A-2-25493, and the like are also included. Can be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount and the like can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable, and furthermore, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrenic compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.
Further, the selection and use method of the polymerized compound is also an important factor for the compatibility and dispersibility with other components in the image recording layer (for example, binder polymer, initiator, colorant, etc.). The compatibility may be improved by using a low-purity compound or using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving the adhesion of the substrate and the protective layer described later.
The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass with respect to the nonvolatile component in the image recording layer. These may be used alone or in combination of two or more.
In addition, the usage of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer construction and coating method such as undercoating and overcoating can also be carried out.

<(D) Hydrophobized precursor>
In the present invention, the hydrophobized precursor is a fine particle capable of converting the image recording layer to hydrophobic when heat is applied. The fine particles are preferably at least one particle selected from hydrophobic thermoplastic polymer fine particles and heat-reactive polymer fine particles.

  As the hydrophobic thermoplastic polymer fine particles used for the image recording layer, Research Disclosure No. 33303 of January 1992, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, The hydrophobic thermoplastic polymer fine particles described in JP-A No.-171250 and European Patent No. 931647 may be mentioned as preferable examples. Specific examples of the polymer constituting the polymer fine particle include homopolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, or the like. Mention may be made of copolymers or mixtures thereof. Among them, more preferred are polystyrene and polymethyl methacrylate.

The average particle size of the hydrophobic thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm.
Examples of the method for synthesizing the hydrophobic thermoplastic polymer fine particles having the above-mentioned particle size that can be used as a hydrophobizing precursor include an emulsion polymerization method and a suspension polymerization method. In addition, these compounds are dissolved in a water-insoluble organic solvent. There is a method (solution-dispersion method) in which this is mixed and emulsified with an aqueous solution containing a dispersant, and further heated to solidify into fine particles while flying off the organic solvent.

  Examples of the heat-reactive polymer fine particles that can be used as a hydrophobizing precursor in the present invention include thermosetting polymer fine particles and polymer fine particles having a heat-reactive group. These include cross-linking by thermal reaction and functional groups at that time. The change forms a hydrophobic region.

  Examples of the thermosetting polymer include a resin having a phenol skeleton, a urea resin (for example, urea or a derivatized urea derivative such as methoxymethylated urea with an aldehyde such as formaldehyde), a melamine resin (for example, melamine or its And the like), alkyd resins, unsaturated polyester resins, polyurethane resins, epoxy resins, and the like. Among these, resins having a phenol skeleton, melamine resins, urea resins and epoxy resins are particularly preferable.

Suitable resins having a phenol skeleton include, for example, phenol resins obtained by converting phenol, cresol and the like with aldehydes such as formaldehyde, hydroxystyrene resins, N- (p-hydroxyphenyl) methacrylamide, and p-hydroxyphenyl methacrylate. Examples thereof include a polymer or copolymer of methacrylamide or acrylamide or methacrylate or acrylate having a phenol skeleton.

  The average particle diameter of the thermosetting polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm. Such thermosetting polymer fine particles can be easily obtained by a solution dispersion method, but may be formed into fine particles when the thermosetting polymer is synthesized. However, it is not restricted to these methods.

  The thermally reactive group of the polymer fine particle having a thermally reactive group used in the present invention may be any functional group that undergoes a reaction as long as a chemical bond is formed, but is an ethylenically unsaturated group that undergoes a radical polymerization reaction. Group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationically polymerizable group (for example, vinyl group, vinyloxy group, etc.), isocyanate group that performs addition reaction or its block, epoxy group, vinyloxy group And a functional group having an active hydrogen atom as a reaction partner thereof (for example, an amino group, a hydroxyl group, a carboxyl group, etc.), a carboxyl group for performing a condensation reaction, a hydroxyl group or an amino group as a reaction partner, a ring-opening addition reaction Suitable acid anhydride and reaction partner amino group or hydroxyl group It can gel.

  The introduction of these functional groups into the polymer fine particles may be performed at the time of polymerization, or may be performed using a polymer reaction after the polymerization.

  When introduced at the time of polymerization, the monomer having the above functional group is preferably subjected to emulsion polymerization or suspension polymerization. Specific examples of the monomer having the above functional group include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, 2- (vinyloxy) ethyl methacrylate, p-vinyloxystyrene, p- {2- (vinyloxy) ethyl} styrene, Block isocyanate with glycidyl methacrylate, glycidyl acrylate, 2-isocyanatoethyl methacrylate or alcohol thereof, block isocyanate with 2-isocyanate ethyl acrylate or alcohol, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2- Hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, Such as functional methacrylates include, but are not limited to.

  In the present invention, a copolymer of these monomers and a monomer that is copolymerizable with these monomers and does not have a thermally reactive group can also be used. Examples of the copolymer monomer having no heat-reactive group include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, vinyl acetate, and the like. It is not limited to.

  Examples of the polymer reaction used when the introduction of the thermally reactive group is carried out after the polymerization include the polymer reaction described in International Publication No. 96/34316 pamphlet.

  Among the polymer fine particles having a heat-reactive group, those in which the polymer fine particles are coalesced by heat are preferable, and those having a hydrophilic surface and being dispersed in water are particularly preferable. The contact angle (water droplets) of the film prepared by applying only polymer fine particles and drying at a temperature lower than the solidification temperature is higher than the contact angle (water droplets) of the film prepared by drying at a temperature higher than the solidification temperature. It is preferable to lower. In order to make the surface of the polymer fine particles hydrophilic in this way, a hydrophilic polymer or oligomer such as polyvinyl alcohol or polyethylene glycol or a hydrophilic low molecular weight compound may be adsorbed on the surface of the polymer fine particles. However, the surface hydrophilization method is not limited to this.

  The solidification temperature of the polymer fine particles having these thermoreactive groups is preferably 70 ° C. or higher, but more preferably 100 ° C. or higher in view of the stability over time. The average particle size of the polymer fine particles is preferably 0.01 to 2.0 μm, more preferably 0.05 to 2.0 μm, and most preferably 0.1 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.

<Microcapsules and / or microgels>
In the present invention, several modes can be used as a method for incorporating the above-mentioned image recording layer constituent components (A) to (C) and other constituent components described later into the image recording layer. One is a molecular dispersion type image recording layer in which the constituent components are dissolved and applied in an appropriate solvent as described in, for example, JP-A-2002-287334. In another embodiment, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or a part of the constituent components are encapsulated in microcapsules and contained in the image recording layer. It is a microcapsule type image recording layer. Further, in the microcapsule type image recording layer, the constituent component can be contained outside the microcapsule. Here, it is preferable that the microcapsule-type image recording layer includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule.
As still another embodiment, an embodiment in which the image recording layer contains crosslinked resin particles, that is, microgel, can be mentioned. The microgel can contain a part of the constituent components (A) to (C) in and / or on the surface thereof. In particular, an embodiment in which (C) a reactive microgel is formed by having a polymerizable compound on the surface thereof is particularly preferable from the viewpoint of image forming sensitivity and printing durability.
In order to obtain better developability, the image recording layer is preferably a microcapsule type or microgel type image recording layer.

As a method for microencapsulating or microgelling the components of the image recording layer, known methods can be applied.
For example, as a method for producing microcapsules, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a system wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, it is not limited to these.

A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. 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 the below-mentioned binder polymer.

On the other hand, as a method for preparing the microgel, granulation by interfacial polymerization described in JP-B-38-19574 and JP-A-42-446, as described in JP-A-5-61214, etc. It is possible to utilize granulation by non-aqueous dispersion polymerization. However, it is not limited to these methods.
As the method using the interfacial polymerization, the above-described known microcapsule production method can be applied.

  Preferred microgels used in the present invention are those granulated by interfacial polymerization and having three-dimensional crosslinking. From such a viewpoint, the material to be used is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and polyurea and polyurethane are particularly preferable.

  The average particle size of the microcapsules or microgel is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

<Other Image Recording Layer Components> The image recording layer of the present invention may further contain various additives as necessary. These will be described below.

<1> Binder polymer In the image recording layer of the present invention, a binder polymer can be used in order to improve the film strength of the image recording layer. As the binder polymer that can be used in the present invention, conventionally known binder polymers can be used without limitation, and polymers having film properties are preferred. Examples of such binder polymers include acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, and synthetic rubbers. And natural rubber.
The binder polymer may have crosslinkability 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.
Examples of the polymer having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ¹ ═CR ² R ³ and — (CH ₂ CH ₂ O) ₂ —X (wherein R ^{1 to} R ³ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, Represents an alkoxy group or an aryloxy group, and R ¹ and R ² or R ³ may combine with each other to form a ring, n represents an integer of 1 to 10. X represents dicyclopentadienyl. Represents a residue).
Specific examples of the ester _{residue, -CH 2 CH = CH 2,} ( described in JP Kokoku _{7-21633.) - CH 2 CH 2} O-CH 2 CH = CH 2, -CH 2 C (CH ₃ )
_{= CH 2, -CH 2 CH =} CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and -CH ₂ CH ₂ OX (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ —OCO—CH═CH _2. Is mentioned.

  In the case of a binder polymer having crosslinkability, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) are added to the crosslinkable functional group, and a polymerization chain of a polymerizable compound is formed directly between 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 to each other so that crosslinking between the polymer molecules occurs. 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, more preferably 1.0, per 1 g of the binder polymer. -7.0 mmol, most preferably 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

  Further, from the viewpoint of improving the developability of the unexposed portion of the image recording layer, the binder polymer preferably has high solubility or dispersibility in ink and / or fountain solution. In order to improve the solubility or dispersibility in ink, the binder polymer is preferably lipophilic, and in order to improve the solubility or dispersibility in dampening water, the binder polymer is hydrophilic. Is preferred. For this reason, in the present invention, it is also effective to use a lipophilic binder polymer and a hydrophilic binder polymer in combination.

  Examples of the hydrophilic binder polymer include hydroxyl group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, and ammonium. Preferred are those having a hydrophilic group such as a group, an amide group, a carboxymethyl group, a sulfonic acid group, and a phosphoric acid group.

  Specific examples include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, Polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

The binder polymer preferably has a mass average molar mass (Mw) of 5000 or more, more preferably 10,000 to 300,000, and the number average molar mass (Mn) is preferably 1000 or more. More preferably, it is 2000-250,000. The polydispersity (Mw / Mn) is preferably 1.1-10.

  The binder polymer can be obtained by purchasing a commercial product or synthesizing it by a known method.

The content of the binder polymer is 5 to 90% by mass, preferably 5 to 80% by mass, and more preferably 10 to 70% by mass with respect to the total solid content of the image recording layer. Within this range, good image area strength and image formability can be obtained.
Further, (C) the polymerizable compound and the binder polymer are preferably used in a mass ratio of 0.5 / 1 to 4/1.

<2> Surfactant In the image recording layer of the present invention, a surfactant can be used in order to promote developability and improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

  The anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention 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.
The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Moreover, the fluorine-type surfactant described in each gazette of Unexamined-Japanese-Patent No. 62-170950, 62-226143, and 60-168144 is also mentioned suitably.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 5% by mass with respect to the total solid content of the image recording layer.

<3> Colorant In the image recording layer of the present invention, a dye having large absorption in the visible light region can be used as an image colorant. 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) 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 JP-A-62-2 And dyes described in No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.
When these colorants are used, it is easy to distinguish between an image area after image formation and a non-image area, so it is preferable to add them. The addition amount is 0.01 to 10% by mass with respect to the total solid content of the image recording material.

<4> Print-out agent To the image-recording layer of the invention, a compound that changes color by an acid or a radical can be added in order to produce a print-out image. As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachite Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Industry Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by an acid or radical is 0.01 to 10% by mass with respect to the solid content of the image recording layer.

<5> Polymerization inhibitor A small amount of a thermal polymerization inhibitor is added to the image recording layer of the present invention to prevent unnecessary thermal polymerization of the polymerizable compound (C) during the production or storage of the image recording layer. It is preferable to do this.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t- (Butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred. The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the image recording layer.

<6> Higher fatty acid derivatives and the like In the image recording layer of the present invention, in order to prevent polymerization inhibition by oxygen, higher fatty acid derivatives such as behenic acid and behenic acid amide are added, and the drying process after coating is performed. May be unevenly distributed on the surface of the image recording layer. The amount of the higher fatty acid derivative added is preferably about 0.1 to about 10% by mass with respect to the total solid content of the image recording layer.

<7> Plasticizer The image recording layer of the present invention may contain a plasticizer in order to improve developability.
Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in.
The plasticizer content is preferably about 30% by mass or less based on the total solid content of the image recording layer.

<8> Inorganic fine particles The image recording layer of the present invention may contain inorganic fine particles in order to improve the strength of the cured film and the developability.
As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof can be preferably mentioned. These can be used for strengthening the film, strengthening the interfacial adhesion by surface roughening, and the like.
The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 μm to 3 μm. Within the above range, it is possible to form a non-image portion having excellent hydrophilicity, which is stably dispersed in the image recording layer, sufficiently retains the film strength of the image recording layer, and hardly causes stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 40% by mass or less, and more preferably 30% by mass or less, based on the total solid content of the image recording layer.

<9> Low molecular weight hydrophilic compound The image-recording layer of the invention may contain a hydrophilic low molecular weight compound in order to improve developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid and salts thereof, alkylsulfamic acid and the like Organic sulfamic acids and salts thereof, organic sulfuric acids and salts thereof such as alkyl sulfuric acid and alkyl ether sulfuric acid, organic phosphonic acids and salts thereof such as phenylphosphonic acid, Stone acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids and the like.

  Among these, organic sulfonic acid, organic sulfamic acid, and sodium salt or lithium salt of organic sulfuric acid are preferably used. By containing these compounds in the image recording layer, the developability can be improved without reducing the printing durability.

  Specific examples of organic sulfonates include sodium normal butyl sulfonate, sodium isobutyl sulfonate, sodium sec-butyl sulfonate, sodium tert-butyl sulfonate, sodium normal pentyl sulfonate, and sodium 1-ethylpropyl sulfonate. Sodium hexyl sulfonate, sodium 1,2-dimethylpropyl sulfonate, sodium 2-ethylbutyl sulfonate, sodium cyclohexyl sulfonate, sodium normal heptyl sulfonate, sodium normal octyl sulfonate, sodium tert-octyl sulfonate, normal Sodium nonyl sulfonate, sodium allyl sulfonate, sodium 2-methylallyl sulfonate, sodium benzene sulfonate Sodium p-toluenesulfonate, sodium p-hydroxybenzenesulfonate, sodium p-styrenesulfonate, dimethyl-5-sulfonate sodium isophthalate, disodium 1,3-benzenedisulfonate, 1,3,5-benzenetri Trisodium sulfonate, sodium p-chlorobenzenesulfonate, sodium 3,4-dichlorobenzenesulfonate, sodium 1-naphthylsulfonate, sodium 2-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, 1,5-naphthyldisulfone Examples thereof include disodium acid, disodium 2,6-naphthyldisulfonate, trisodium 1,3,6-naphthyltrisulfonate, and lithium salt exchangers thereof.

  Specific examples of the organic sulfamate include sodium normal butyl sulfamate, sodium isobutyl sulfamate, sodium tert-butyl sulfamate, sodium normal pentyl sulfamate, sodium 1-ethylpropyl sulfamate, sodium normal hexyl sulfamate, Examples include sodium 1,2-dimethylpropylsulfamate, sodium 2-ethylbutylsulfamate, sodium cyclohexylsulfamate, and lithium salt exchangers thereof.

  These compounds have a small hydrophobic part structure and almost no surface-active action, and are clearly distinguished from the above-mentioned surfactants in which long-chain alkyl sulfonates and long-chain alkyl benzene sulfonates are used favorably. .

  As the organic sulfate, a compound represented by the following general formula (3) is particularly preferably used.

In the general formula (3), R represents a substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, aryl group or heterocyclic group, m represents an integer of 1 to 4, and X represents sodium or potassium. Or represents lithium.

  R is preferably a substituted or unsubstituted, linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, alkenyl group having 1 to 12 carbon atoms, alkynyl group having 1 to 12 carbon atoms, carbon number Examples include 20 or less aryl groups. Examples of the substituent include a linear, branched or cyclic 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, a halogen atom, and an aryl having 20 or less carbon atoms. Groups.

  Preferred examples of the compound represented by the general formula (3) include sodium oxyethylene-2-ethylhexyl ether sulfate, sodium dioxyethylene-2-ethylhexyl ether sulfate, potassium dioxyethylene-2-ethylhexyl ether sulfate, dioxy Ethylene-2-ethylhexyl ether lithium sulfate, sodium trioxyethylene-2-ethylhexyl ether sulfate, sodium tetraoxyethylene-2-ethylhexyl ether sulfate, sodium dioxyethylene hexyl ether sulfate, sodium dioxyethylene octyl ether sulfate, dioxyethylene Examples include sodium lauryl ether sulfate. Most preferred compounds include sodium dioxyethylene-2-ethylhexyl ether sulfate, potassium dioxyethylene-2-ethylhexyl ether sulfate, and lithium dioxyethylene-2-ethylhexyl ether sulfate.

  As the low molecular weight compound, a specific isocyanuric acid skeleton compound represented by the following general formula (4) can also be preferably used in addition to the above-mentioned compounds.

In the general formula (4), at least one of R ^{1 to} R ³ is a — (CH ₂ CH ₂ O) _n —R ⁴ group, and R ⁴ is a hydrogen atom or having 1 to 4 carbon atoms. Represents an alkyl group, and n is an integer of 1 to 20. The remaining R ^{1 to} R ³ are each independently a group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and R ⁵ —COOH, and R ⁵ has a carbon number. 1 to 6 alkylene groups are represented.

In the isocyanuric acid skeleton compound used in the present invention, two or more of R ^{1 to} R ³ are preferably — (CH ₂ CH ₂ O) _n —R ⁴ groups from the viewpoint of development efficiency, and preferably three. Particularly preferred are all those that are — (CH ₂ CH ₂ O) _n —R ⁴ groups.
When R ⁴ is an alkyl group having 1 to ⁴ carbon atoms, the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. Is mentioned.
In the — (CH ₂ CH ₂ O) _n —R ⁴ group, from the viewpoint of developability, n is preferably an integer of 1 to 10, more preferably an integer of 1 to 3, , R ⁴ is preferably a hydrogen atom or a methyl group, particularly preferably a hydrogen atom.

When R ^{1 to} R ³ are an alkyl group having 1 to 4 carbon atoms, the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. A methyl group and an ethyl group are preferable.
Further, the ^R 1 to R ³ may for _{^{-R 5 -COOH, -C 2 H 4}} COOH are preferred examples.
The remaining R ^{1 to} R ³ other than the (CH ₂ CH ₂ O) _n —R ⁴ group are preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

  Specific examples of the specific isocyanuric acid skeleton compound used in the present invention include, but are not limited to, compounds represented by structural formulas (D-1) to (D-10) shown below.

  Among these, tris (2-hydroxyethyl) isocyanurate having the structural formula (D-1) is particularly preferable because the balance between development acceleration and printing durability is particularly excellent.

The amount of these low molecular weight hydrophilic compounds added to the image recording layer is 0.5% of the total solid content of the image recording layer.
It is preferable that they are mass% or more and 20 mass% or less. More preferably, they are 1 mass% or more and 10 mass% or less, More preferably, they are 2 mass% or more and 8 mass% or less. In this range, good developability and printing durability can be obtained.
These compounds may be used alone or in combination of two or more.

<10> Grease sensitizing agent When an inorganic layered compound is contained in the protective layer described later, it is preferable to use a phosphonium compound in combination in order to improve the inking property. The phosphonium compound functions as a surface coating agent (grease sensitizing agent) for the inorganic stratiform compound, and prevents deterioration of the inking property during printing by the inorganic stratiform compound.
Examples of preferable phosphonium compounds include compounds represented by the following general formula (5) or general formula (6). More preferable phosphonium compounds include compounds represented by the general formula (5).

In Formula (5), Ar _{1 to} Ar ₆ each independently represents an aryl group or a heterocyclic group, L represents a divalent linking group, X ⁿ⁻ represents an n-valent counter anion, and n represents 1 Represents an integer of ˜3, and m represents a number satisfying nx m = 2.

  Here, as the aryl group, phenyl group, naphthyl group, tolyl group, xylyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, methoxyphenyl group, ethoxyphenyl group, dimethoxyphenyl group, methoxycarbonylphenyl group, dimethylaminophenyl A group and the like are preferable. Examples of the heterocyclic group include a pyridyl group, a quinolyl group, a pyrimidinyl group, a thienyl group, and a furyl group. L is preferably a linking group having 6 to 15 carbon atoms, more preferably a linking group having 6 to 12 carbon atoms.

Preferable examples of X ⁿ⁻ include halogen anions such as Cl ⁻ , Br ⁻ and I ⁻ , sulfonate anions, carboxylate anions, sulfate anions, PF ₆ ⁻ , BF ₄ ⁻ and perchlorate anions. . Among these, halogen anions such as Cl ⁻ , Br ⁻ and I ⁻ , sulfonate anions, and carboxylate anions are particularly preferable.

  Specific examples of the phosphonium compound represented by the general formula (5) are shown below.

In the general formula (6), R _{1 to} R ₄ are each independently an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, alkoxy group, aryl group, aryloxy group, which may have a substituent, Represents an alkylthio group, a heterocyclic group or a hydrogen atom; At least two of R _{1 to} R ₄ may combine to form a ring. X ⁻ represents a counter anion.
Here, when R _{1 to} R ₄ are an alkyl group, an alkoxy group or an alkylthio group, the carbon number is usually 1 to 20, and when R _{1 to} R ₄ is an alkenyl group or an alkynyl group, the carbon number is usually 2 to 15 and a cycloalkyl group. In some cases, the number of carbon atoms is usually 3 to 8, the aryl group is a phenyl group, a naphthyl group, etc., the aryloxy group is a phenoxy group, a naphthyloxy group, etc., the arylthio group is a phenylthio group, etc. Examples of the group include a furyl group and a thienyl group. Examples of the substituent that may be present include, for example, alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, alkoxy groups, alkoxycarbonyl groups, acyl groups, alkylthio groups, aryl groups, aryloxy groups, arylthio groups. Group, sulfino group, sulfo group, phosphino group, phosphoryl group, amino group, nitro group, cyano group, hydroxyl group, halogen atom and the like. These substituents may further have a substituent.
Examples of the anion represented by X ⁻ include halide ions such as Cl ⁻ , Br ⁻ and I ⁻ , inorganic acid anions such as ClO ₄ ⁻ , PF ₆ ⁻ and SO ₄ ⁻² , organic carboxylate anions and organic sulfonate anions. Can be mentioned. Examples of the organic group of the organic carboxylate anion and organic sulfonate anion include methyl, ethyl, propyl, butyl, phenyl, methoxyphenyl, naphthyl, fluorophenyl, difluorophenyl, pentafluorophenyl, thienyl, pyrrolyl and the like. Among these, Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ ⁻ , PF ₆ ^{− and the} like are preferable. Specific examples of the phosphonium compound represented by the general formula (6) are shown below.

  In addition to the above-mentioned phosphonium compound, the following nitrogen-containing low molecular weight compounds can be mentioned as the sensitizers preferably used in the present invention. Preferable nitrogen-containing low molecular weight compounds include compounds having the structure of the following general formula (I).

In the formula, R ^{1 to} R ⁴ each independently represents a substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, cycloalkyl group, alkoxy group, aryl group, aralkyl group, heterocyclic group or hydrogen atom. At least two of R ^{1 to} R ⁴ may combine to form a ring. X ⁻ is an anion, and PF ₆ ⁻ , BF ₄ ⁻ , or an organic sulfone having a substituent selected from an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aralkyl group, and a heterocyclic group Indicates an acid anion.

That the nitrogen-containing low molecular weight compound for use in the present invention include quaternary ammonium salts wherein at least one amine salt is a hydrogen atom R ¹ to R ^4, and R ¹ to R ⁴ is not any hydrogen atom . In addition, imidazolinium salts represented by the following general formula (II), benzimidazolinium salts represented by the following general formula (III), pyridinium salts represented by the following general formula (IV), and the following general formula (V) The quinolinium salt structure may be used.

In the above formula, R ⁵ and R ⁶ represent a substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, cycloalkyl group, alkoxy group, aryl group, aralkyl group, heterocyclic group or hydrogen atom. X ^- is an anion, the general formula (I) X ^- as synonymous.

Among these, quaternary ammonium salts and pyridinium salts are preferably used. Specific examples thereof are shown below.

  The amount of the phosphonium compound or nitrogen-containing low molecular weight compound added to the image recording layer is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, based on the solid content of the image recording layer. 5% by mass is most preferred. Within these ranges, good ink fillability during printing can be obtained.

  As the sensitizer used in the present invention, the following ammonium group-containing polymers are also preferred. The ammonium group-containing polymer may be any polymer having an ammonium group in its structure, but is preferably a polymer containing structures of the following general formula (VI) and general formula (VII) as repeating units.

(Wherein R ¹¹ and R ¹² each independently represent a hydrogen atom or a methyl group. R ² represents an alkylene group which may have a substituent, an alkyleneoxy group which may have a substituent, etc. R ³¹ , R ³² and R ³³ each independently represents an alkyl group having 1 to 10 carbon atoms or an aralkyl group, and X ⁻ represents F ⁻ , Cl ⁻ , Br ⁻ , I ^−. Benzenesulfonic acid anion which may have a substituent, methyl sulfate anion, ethyl sulfate anion, propyl sulfate anion, butyl sulfate anion which may be branched, amyl sulfate anion which may be branched, PF ₆ ⁻ , BF _{4 ^{-, B (C 6 F 5}} ) 4 - is .R ⁴ represents an organic or inorganic anion such as an alkyl group having 1 to 21 carbon atoms, an aralkyl group, an aryl _{group, - (C 2 H 4 O} ) -
R ⁵ or (C ₃ H ₆ O) _n —R ⁵ is represented, and R ⁵ represents a hydrogen atom, a methyl group or an ethyl group. n represents 1 or 2. )

  The ammonium salt-containing polymer contains at least one structural unit represented by general formula (VI) and general formula (VII), but either one may be two or more, and both are 2 There may be more than species. The ratio of both structural units is not limited, but is preferably 5:95 to 80:20. Moreover, this polymer may contain another copolymerization component within the range which can ensure the effect of this invention.

  The ammonium salt-containing polymer has a reduced specific viscosity (unit: cSt / g / ml) determined by the following measurement method, preferably in the range of 5 to 120, more preferably in the range of 10 to 110. The range of 15-100 is especially preferable.

<Measurement method of reduced specific viscosity>
Weigh 3.33 g of 30% polymer solution (1 g as solid content) into a 20 ml volumetric flask and make up with N-methylpyrrolidone. This solution is put into an Ubbelohde reduced viscosity tube (viscosity constant = 0.010 cSt / s), and the time for which it flows at 30 ° C. is measured, and the calculation (“kinematic viscosity” = “viscosity constant” × “ Time to pass (second) ") is calculated by the usual method.

The content of the ammonium salt-containing polymer is preferably 0.0005% by mass to 30.0% by mass, more preferably 0.001% by mass to 20.0% by mass with respect to the total solid content of the image recording layer. 002% by mass to 15.0% by mass is most preferable. Within this range, good inking properties can be obtained.
Specific examples of the ammonium salt-containing polymer are shown below.

  The present sensitizer can be added not only to the image recording layer but also to the protective layer.

<Formation of image recording layer>
The image recording layer of the present invention is applied by preparing a coating solution by dispersing or dissolving each of the necessary components in a solvent. 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 mass.
The image recording layer of the present invention can 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 coatings and dryings.

Further, the coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the use, but generally 0.3 to 3.0 g / m ² is preferable. Within this range, good sensitivity and good film properties of the image recording layer can be obtained.
Various methods can be used as a 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 (overcoat layer) is preferably provided on the image recording layer. In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer also has functions such as preventing scratches in the image recording layer and preventing ablation during high-illuminance laser exposure. Below, the component etc. of the protective layer of this invention are demonstrated.

  Usually, the exposure processing of a lithographic printing plate is carried out in the atmosphere. The image forming reaction in the image recording layer caused by the exposure process can be inhibited by low molecular compounds such as oxygen and basic substances present in the atmosphere. The protective layer prevents low molecular compounds such as oxygen and basic substances from entering the image recording layer, and as a result, suppresses image formation inhibition reaction in the air. Therefore, the property desired for the protective layer is to reduce the permeability of low-molecular compounds such as oxygen, and furthermore, the transparency of light used for exposure is good, and the adhesiveness with the image recording layer is excellent. In addition, it can be easily removed in the development process after exposure. The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and JP-B-55-49729.

  As a material used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used. Specifically, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, polyacrylic acid, polyacrylamide, partially saponified product of polyvinyl acetate, ethylene-vinyl alcohol copolymer, water-soluble cellulose derivative, gelatin, starch Examples thereof include water-soluble polymers such as derivatives and gum arabic, and polymers such as polyvinylidene chloride, poly (meth) acrylonitrile, polysulfone, polyvinyl chloride, polyethylene, polycarbonate, polystyrene, polyamide, and cellophane. These may be used in combination of two or more as required.

  A relatively useful material among the above materials includes water-soluble polymer compounds having excellent crystallinity. Specifically, water-soluble acrylic resins such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, and polyacrylic acid, gelatin, gum arabic, and the like are suitable. Among them, water can be applied as a solvent, and at the time of printing Polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl imidazole are preferable from the viewpoint that they are easily removed by a fountain solution. Among them, polyvinyl alcohol (PVA) gives the best results for basic properties such as oxygen barrier properties and development removability.

  The polyvinyl alcohol that can be used in the protective layer may be partially substituted with esters, ethers, and acetals as long as they contain a substantial amount of unsubstituted vinyl alcohol units having the required water solubility. Similarly, a part may contain other copolymerization components. 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. Polyvinyl alcohol having various degrees of polymerization having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, etc. at the polymer chain end is also preferably used.

Suitable examples of the modified polyvinyl alcohol include compounds having a hydrolysis degree of 71 to 100 mol% and a polymerization degree in the range of 300 to 2400. 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 etc. are mentioned. Examples of the modified polyvinyl alcohol include KL-318, KL-118, KM-618, KM-118, SK-5102 having an anion-modified site, C-318, C-118, and CM-318 having a cation-modified site. M-205 and M-115 having terminal thiol modification sites, MP-103, MP-203, MP-102, MP-202 having terminal sulfide modification sites, and ester modification sites with higher fatty acids HL-12E, HL-1203, and other reactive silane-modified R-1130, R-2105, R-2130, and the like.

The protective layer preferably contains an inorganic stratiform compound. The layered compound is a particle having a thin plate-like shape. For example, the following general formula A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
[However, A is any of Li, K, Na, Ca, Mg, organic cation, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.
Examples of the natural mica include muscovite, soda mica, phlogopite, biotite and sericite. In addition, examples of the synthetic mica include non-swelling mica such as fluorine phlogopite mica ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) F ₂ , and Na tetrasilicic mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , montmorillonite-based Na or Li hectorite (Na, Li) 1/8 Mg _{2 / 5Li 1/8 (Si 4} O 10) swelling mica _{F 2.} Synthetic smectite is also useful.

Among the above layered compounds, fluorine-based swellable mica which is a synthetic layered compound is particularly useful. That is, swellable clay minerals such as mica, montmorillonite, saponite, hectorite, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and metal atom substitution in the lattice is other than Significantly greater than viscous minerals. As a result, the lattice layer is deficient in positive charge, and in order to compensate for it, organic cations such as Li ⁺ , Na ⁺ , Ca ²⁺ , Mg ²⁺ , amine salts, quaternary ammonium salts, phosphonium salts and sulfonium salts are used between Adsorbs cations. These layered compounds swell with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swelling synthetic mica have this tendency.

As the shape of the layered compound, from the viewpoint of diffusion control, the thinner the better, the better the plane size as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.
As for the particle diameter of the layered compound, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. When the particle diameter is smaller than 0.3 μm, the suppression of permeation of oxygen and moisture is insufficient, and the effect cannot be sufficiently exhibited. On the other hand, if it is larger than 20 μm, the dispersion stability in the coating solution is insufficient, resulting in a problem that stable coating cannot be performed. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, and particularly preferably 0.01 μm or less. For example, among the inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When the inorganic layered compound particles having such 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. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.

  Next, an example of a general dispersion method when a layered compound is used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable laminar compound mentioned above as a preferred laminar compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. A dispersion of 5 to 10% by mass of the inorganic stratiform compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a protective layer coating solution using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder solution.

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

The inorganic layered compound can be added not only to the protective layer but also to the image recording layer. Addition of an inorganic layered compound to the image recording layer is useful for improving printing durability, polymerization efficiency (sensitivity), and stability over time.
The amount of the inorganic stratiform compound added to the image recording layer is preferably from 0.1 to 50 mass%, more preferably from 0.3 to 30 mass%, most preferably from 1 to 10 mass%, based on the solid content of the image recording layer. preferable.

  As other additives for the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the water-soluble or water-insoluble polymer to give flexibility. Anionic surfactants such as sodium alkyl sulfonate; amphoteric surfactants such as alkylaminocarboxylate and alkylaminodicarboxylate; nonionic surfactants such as polyoxyethylene alkylphenyl ether can be added. These active agents can be added in an amount of 0.1 to 100% by mass with respect to the water-soluble or water-insoluble polymer.

In order to improve the adhesion to the image area, for example, JP-A-49-70702 and British Patent Application No. 1303578 disclose an acrylic polymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesion can be obtained by mixing 20 to 60% by mass of a water-based emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer and the like, and laminating the mixture on an image recording layer. Any of these known techniques can be used in the present invention.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (for example, a water-soluble dye) that is excellent in the transparency of infrared rays used for exposure and that can efficiently absorb light of other wavelengths, safe light is not caused. Suitability can be improved.

The protective layer is formed by applying and drying a protective layer coating solution prepared by dispersing or dissolving the protective layer component in a solvent on the image recording layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water.
This protective layer coating solution includes known anionic surfactants, nonionic surfactants, cationic surfactants, fluorosurfactants and water-soluble plasticizers for improving the physical properties of the coating. Additives can be added. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, a known additive for improving the adhesion with the image recording layer and the temporal stability of the coating solution may be added to the coating solution.
The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. . Specific examples of the protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.

The coating amount of the protective layer of the coating amount after drying is preferably in the range of 0.01 to 10 g / ^{m 2,} more preferably in the range of 0.02 to 3 g / ^{m 2,} and most preferably 0. in the range of 02~1g / ^{m 2.}

(Support)
The support 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 material. 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.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, 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 different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. 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.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion between the image recording 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 (surface roughening treatment for dissolving the surface electrochemically), 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. Moreover, the transcription | transfer method which transfers an uneven | corrugated shape with the roll which provided the unevenness | corrugation in the rolling stage of aluminum can also 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, 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 of anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. 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 this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is. However, in order to further improve the adhesiveness with the upper layer, hydrophilicity, dirt resistance, heat insulation and the like. If necessary, it is immersed in an aqueous solution containing a hydrophilic compound and a micropore enlargement treatment or sealing treatment of an anodized film described in JP-A-2001-253181 or JP-A-2001-322365. The surface hydrophilization treatment to be performed can be appropriately selected and performed. Of course, the enlargement process and the sealing process are not limited to those described above, and any conventionally known methods can be performed. For example, as the sealing treatment, in addition to the vapor sealing, a single treatment with fluorinated zirconic acid, a treatment with sodium fluoride, and a vapor sealing with addition of lithium chloride are possible.

  The sealing treatment used in the present invention is not particularly limited, and a conventionally known method can be used. Among them, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing with hot water are particularly preferable. Hole treatment is preferred. Each will be described below.

<1> Sealing treatment with an aqueous solution containing an inorganic fluorine compound As the inorganic fluorine compound used for the sealing treatment with an aqueous solution containing an inorganic fluorine compound, a metal fluoride is preferably exemplified.
Specifically, for example, sodium fluoride, potassium fluoride, calcium fluoride, magnesium fluoride, sodium fluoride zirconate, potassium fluoride zirconate, sodium fluoride titanate, potassium fluoride titanate, zircon fluoride Ammonium acid, ammonium fluoride titanate, potassium fluoride titanate, zirconate fluoride, titanate fluoride, hexafluorosilicic acid, nickel fluoride, iron fluoride, phosphor fluoride, ammonium fluoride phosphate It is done. Among these, sodium fluorinated zirconate, sodium fluorinated titanate, fluorinated zirconic acid, and fluorinated titanic acid are preferable.

  The concentration of the inorganic fluorine compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, from the viewpoint of sufficiently sealing the micropores of the anodized film. Further, in terms of stain resistance, it is preferably 1% by mass or less, and more preferably 0.5% by mass or less.

  It is preferable that the aqueous solution containing the inorganic fluorine compound further contains a phosphate compound. When the phosphate compound is contained, the hydrophilicity of the surface of the anodized film is improved, so that the developability and stain resistance can be improved.

Suitable examples of the phosphate compound include phosphates of metals such as alkali metals and alkaline earth metals.
Specifically, for example, zinc phosphate, aluminum phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, monoammonium phosphate, monopotassium phosphate, monosodium phosphate, dihydrogen phosphate Potassium, dipotassium hydrogen phosphate, calcium phosphate, sodium ammonium hydrogen phosphate, magnesium hydrogen phosphate, magnesium phosphate, ferrous phosphate, ferric phosphate, sodium dihydrogen phosphate, sodium phosphate, hydrogen phosphate Disodium, lead phosphate, diammonium phosphate, calcium dihydrogen phosphate, lithium phosphate, phosphotungstic acid, phosphotungstic acid, sodium phosphotungstate, ammonium phosphomolybdate, sodium phosphomolybdate, sodium phosphite , Tripolyphosphate Potassium, and sodium pyrophosphate. Among these, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate are preferable.
The combination of the inorganic fluorine compound and the phosphate compound is not particularly limited, but the aqueous solution contains at least sodium zirconate fluoride as the inorganic fluorine compound and contains at least sodium dihydrogen phosphate as the phosphate compound. Is preferred.

  The concentration of the phosphate compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of improving developability and stain resistance, In terms of solubility, it is preferably 20% by mass or less, and more preferably 5% by mass or less.

The ratio of each compound in the aqueous solution is not particularly limited, but the mass ratio of the inorganic fluorine compound and the phosphate compound is preferably 1/200 to 10/1, and preferably 1/30 to 2/1. Is more preferable.
The temperature of the aqueous solution is preferably 20 ° C. or higher, more preferably 40 ° C. or higher, preferably 100 ° C. or lower, more preferably 80 ° C. or lower.
The aqueous solution preferably has a pH of 1 or more, more preferably has a pH of 2 or more, preferably has a pH of 11 or less, and more preferably has a pH of 5 or less.
The method for sealing with an aqueous solution containing an inorganic fluorine compound is not particularly limited, and examples thereof include an immersion method and a spray method. These may be used alone or in combination, or may be used in combination of two or more.
Of these, the dipping method is preferred. When the treatment is performed using the dipping method, the treatment time is preferably 1 second or longer, more preferably 3 seconds or longer, and preferably 100 seconds or shorter, and 20 seconds or shorter. More preferred.

<2> Sealing treatment with water vapor Sealing treatment with water vapor includes, for example, a method in which pressurized or normal pressure water vapor is brought into contact with the anodized film continuously or discontinuously.
The temperature of the water vapor is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 105 ° C. or lower.
The water vapor pressure is preferably in the range (1.008 × 10 ^{5 to} 1.043 × 10 ⁵ Pa) from (atmospheric pressure−50 mmAq) to (atmospheric pressure + 300 mmAq).
Further, the time for which the water vapor is contacted is preferably 1 second or longer, more preferably 3 seconds or longer, 100 seconds or shorter, more preferably 20 seconds or shorter.

<3> Sealing treatment with hot water Examples of the sealing treatment with hot water include a method in which an aluminum plate on which an anodized film is formed is immersed in hot water.
The hot water may contain an inorganic salt (for example, phosphate) or an organic salt.
The temperature of the hot water is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 100 ° C. or lower.
Further, the time of immersion in hot water is preferably 1 second or longer, more preferably 3 seconds or longer, more preferably 100 seconds or shorter, and even more preferably 20 seconds or shorter.

  The hydrophilization treatment is described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are alkali metal silicate methods. In this method, the support is subjected to immersion treatment or electrolytic treatment with an aqueous solution such as sodium silicate. 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 each specification of No.272.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis and condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer comprising an inorganic thin film having a surface Preferred. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a 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 this range, good adhesion to the image recording layer, good printing durability and good stain resistance can be obtained.

(Back coat layer)
After the surface treatment is applied to the support or after an undercoat layer (described later) 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. Of these, the use of silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4, etc. is inexpensive. It is preferable in terms of easy availability.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, an undercoat layer can be provided between the image recording layer and the support, if necessary. The undercoat layer tends to cause peeling of the image recording layer from the support in the unexposed area, so that developability is improved. In addition, in the case of infrared laser exposure, since the undercoat layer functions as a heat insulating layer, the heat generated by exposure does not diffuse to the support and can be used efficiently, so that the sensitivity can be increased. is there.
Specific examples of the undercoat layer compound (undercoat compound) include silane coupling agents having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, Preferable examples include phosphorus compounds having an ethylenic double bond reactive group described in Kaihei 2-304441.
The most preferable undercoat compound includes a polymer resin obtained by copolymerizing a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group.

An essential component of the undercoat polymer resin is an adsorptive group on the hydrophilic support surface. The presence or absence of adsorptivity on the surface of the hydrophilic support can be determined by the following method, for example.
A coating night is prepared by dissolving the test compound in a readily soluble solvent, and the coating night is coated and dried on the support so that the coating amount after drying is 30 mg / m ² . Next, the support on which the test compound is applied is sufficiently washed with an easily soluble solvent, and then the residual amount of the test compound that has not been removed by washing is measured to calculate the amount of adsorption of the support. Here, the measurement of the remaining amount may be performed by directly quantifying the amount of the remaining compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. The compound can be quantified by, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, liquid chromatography measurement and the like. The compound having support adsorptivity is a compound that remains at 1 mg / m ² or more even after the above-described washing treatment.

The adsorptive group on the surface of the hydrophilic support is a substance (for example, metal, metal oxide) or a functional group (for example, hydroxyl group) existing on the surface of the hydrophilic support and a chemical bond (for example, ionic bond, hydrogen). Bond, coordination bond, bond by intermolecular force). The adsorptive group is preferably an acid group or a cationic group.
The acid group preferably has an acid dissociation constant (pKa) of 7 or less. Examples of the acid group include a phenolic hydroxyl group, a carboxyl _{group, -SO 3 H, -OSO 3 H} , -PO 3 H 2, -OPO 3 H 2, -CONHSO 2 -, - SO 2 NHSO 2 - and -COCH ₂ COCH ₃ is included. Among them -OPO ₃ H ₂ and _-PO 3 _{H 2} are particularly preferred. These acid groups may be metal salts.
The cationic group is preferably an onium group. Examples of the onium group include an ammonium group, a phosphonium group, an arsonium group, a stibonium group, an oxonium group, a sulfonium group, a selenonium group, a stannonium group, and an iodonium group. An ammonium group, a phosphonium group and a sulfonium group are preferred, an ammonium group and a phosphonium group are more preferred, and an ammonium group is most preferred.

  Particularly preferable examples of the monomer having an adsorptive group include compounds represented by the following formula (U1) or (U2).

In the above formula, R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms. R ¹ , R ² and R ³ are each independently preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferred is a hydrogen atom or a methyl group. R ² and R ³ are particularly preferably a hydrogen atom. Z is a functional group that adsorbs to the surface of the hydrophilic support.
In the formula (U1), X is an oxygen atom (—O—) or imino (—NH—). X is more preferably an oxygen atom. In the formula (U1), L is a divalent linking group. L is a divalent aliphatic group (alkylene group, substituted alkylene group, alkenylene group, substituted alkenylene group, alkynylene group, substituted alkynylene group), divalent aromatic group (arylene group, substituted arylene group) or divalent Or an oxygen atom (—O—), a sulfur atom (—S—), an imino (—NH—), a substituted imino (—NR—, where R is an aliphatic group, an aromatic group. Or a combination with a heterocyclic group) or carbonyl (—CO—).
The aliphatic group may have a cyclic structure or a branched structure. The number of carbon atoms in the aliphatic group is preferably 1 to 20, more preferably 1 to 15, and most preferably 1 to 10. The aliphatic group is preferably a saturated aliphatic group rather than an unsaturated aliphatic group. The aliphatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aromatic group, and a heterocyclic group.
The number of carbon atoms in the aromatic group is preferably 6 to 20, more preferably 6 to 15, and most preferably 6 to 10. The aromatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aliphatic group, an aromatic group, and a heterocyclic group.
The heterocyclic group preferably has a 5-membered or 6-membered ring as the heterocycle. The heterocycle may be condensed with another heterocycle, aliphatic ring or aromatic ring. The heterocyclic group may have a substituent. Examples of substituents include halogen atoms, hydroxyl groups, oxo groups (═O), thioxo groups (═S), imino groups (═NH), substituted imino groups (═N—R, R is an aliphatic group, aromatic Group or heterocyclic group), aliphatic group, aromatic group and heterocyclic group.
L is preferably a divalent linking group containing a plurality of polyoxyalkylene structures. The polyoxyalkylene structure is more preferably a polyoxyethylene structure. In other words, L preferably contains — (OCH ₂ CH ₂ ) _n — (n is an integer of 2 or more).
In the formula (U2), Y is a carbon atom or a nitrogen atom. When Y is a nitrogen atom and L is connected to Y to form a quaternary pyridinium group, Z itself is adsorbable, so Z is not essential, and Z may be a hydrogen atom. L represents the same divalent linking group or single bond as in formula (U1).

The adsorptive functional group is as described above.
Examples of typical compounds represented by formula (U1) or (U2) are shown below.

  Examples of the hydrophilic group of the undercoat polymer resin that can be used in the present invention include a hydroxyl group, a carboxyl group, a carboxylate group, a hydroxyethyl group, a polyoxyethyl group, a hydroxypropyl group, a polyoxypropyl group, and an amino group. Preferred examples include a group, an aminoethyl group, an aminopropyl group, an ammonium group, an amide group, a carboxymethyl group, a sulfonic acid group, and a phosphoric acid group. Among them, a monomer having a sulfonic acid group exhibiting high hydrophilicity is preferable. Specific examples of the monomer having a sulfonic acid group include methallyloxybenzenesulfonic acid, allyloxybenzenesulfonic acid, allylsulfonic acid, vinylsulfonic acid, p-styrenesulfonic acid, methallylsulfonic acid, acrylamide t-butylsulfonic acid. Examples include 2-acrylamido-2-methylpropanesulfonic acid, sodium salt of (3-acryloyloxypropyl) butylsulfonic acid, and amine salt. Among them, 2-acrylamido-2-methylpropanesulfonic acid sodium salt is preferable from the viewpoint of hydrophilic performance and synthetic handling.

  The water-soluble polymer resin for the undercoat layer of the present invention preferably has a crosslinkable group. The crosslinkable group can improve the adhesion with the image area. In order to make the polymer resin for the undercoat layer crosslinkable, a crosslinkable functional group such as an ethylenically unsaturated bond is introduced into the side chain of the polymer, or the polar substituent of the polymer resin is countercharged. Or a compound having an ethylenically unsaturated bond may be introduced by forming a salt structure.

  Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ₁ ═CR ₂ R ₃ and — (CH ₂ CH ₂ O) ₂ —X (wherein R _{1 to} R ₃ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group. ,
Represents an alkoxy group or an aryloxy group, and R ₁ and R ₂ or R ₃ may be bonded to each other to form a ring; n represents an integer of 1 to 10. X represents a dicyclopentadienyl residue. ).
Specific examples of the ester residue include —CH ₂ CH═CH ₂ (described in JP-B-7-21633), —CH ₂ CH ₂ O—CH ₂ CH═CH ₂ , —CH ₂ C. _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 NHCOO-CH 2 CH = CH 2, and - CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ O—Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ OCO—CH═CH _2. Is mentioned.
As the monomer having a crosslinkable group of the polymer resin for the undercoat layer, an ester or amide of acrylic acid or methacrylic acid having the crosslinkable group is preferable.

  The content of the crosslinkable group in the polymer resin for the undercoat layer (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 polymer resin. Preferably it is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol. Within this range, both good sensitivity and dirtiness and good storage stability can be obtained.

The polymer resin for the undercoat layer preferably has a mass average molar mass (Mw) of 5000 or more, more preferably 10,000 to 300,000, and a number average molar mass (Mn) of 1000 or more. It is preferable that it is 2000 to 250,000. The polydispersity (Mw / Mn) is preferably 1.1-10.
The polymer resin for the undercoat layer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.
The undercoat polymer resin may be used alone or in combination of two or more.

  The undercoat layer of the present invention can contain a secondary or tertiary amine. These amines suppress pot-like dirt. Preferable secondary or tertiary amines include the following compounds.

  In the present invention, two or more of these amines may be contained in the undercoat layer. The amount of amine added to the undercoat layer is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and most preferably 30 to 70% by mass of the constituent components of the undercoat layer.

The undercoat layer coating solution is obtained by dissolving the above-described undercoat polymer resin and other necessary components in an organic solvent (eg, methanol, ethanol, acetone, methyl ethyl ketone, etc.) and / or water. The undercoat layer coating solution may contain an infrared absorber.
Various known methods can be used as a method of applying the undercoat layer coating solution to the support. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / ^{m 2,} and more preferably 1 to 30 mg / ^{m 2.}

[Plate making method]
The exposure light source used in the present invention is preferably a laser. Although the laser used for this invention is not specifically limited, The solid laser and semiconductor laser which irradiate infrared rays with a wavelength of 760-1200 nm, the semiconductor laser etc. which irradiate 250-420 nm light etc. are mentioned suitably.
Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . In a semiconductor laser that emits light of 250 to 420 nm, the output is preferably 0.1 mW or more. In any laser, it is preferable to use a multi-beam laser device in order to shorten the exposure time.

The planographic printing plate precursor exposed imagewise with a laser such as an infrared laser is developed with a developer having a pH of 3-9. The developing solution is more preferably a gum solution containing a desensitizing agent in terms of desensitization after development, and the pH of the developing solution is more preferably 4-8.
Below, the component used for said developing solution is demonstrated.

The developer of the present invention preferably contains a desensitizing agent.
As the desensitizing agent, gum arabic is preferable, and an aqueous solution of about 15 to 20% by mass of gum arabic can be used as a developer. In addition to gum arabic, various water-soluble resins are used as a desensitizing agent. For example, water-soluble polysaccharides extracted from dextrin, steravic, structan, alginates, polyacrylates, hydroxyethylcellulose, polyvinylpyrrolidone, polyacrylamide, methylcellulose, hydroxypropylcellulose, hydroxymethylcellulose, carboxyalkylcellulose salts, soybean okara In addition, pullulan or pullulan derivatives and polyvinyl alcohol are also preferable.

  Further, as modified starch derivatives, roasted starch such as British gum, enzyme modified dextrins such as enzyme dextrin and shardinger dextrin, oxidized starch shown in solubilized starch, modified starch pregelatinized and unmodified gelatinized 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, carbamyl Etherified starch such as ethyl starch and dialkylamino starch, methylol cross-linked starch, hydroxyalkyl cross-linked starch, cross-linked starch such as phosphoric acid cross-linked starch and dicarboxylic acid cross-linked starch, starch polyacrylamide copolymer, starch polyacrylic acid copolymer Starch polyvinyl acetate copolymer, starch polyacrylonitrile copolymer, chaotic starch polyacrylate copolymer, chaotic starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer, Starch graft polymers such as starch polypropylene copolymers are preferred.

  Natural polymers include starches such as candy starch, potato starch, tapioca starch, wheat starch and corn starch, carrageenan, laminaran, seaweed mannan, funari, Irish moss, agar and algae such as sodium alginate. , Plant mucilage such as troroaoy, mannan, quince seed, pectin, tragacanth gum, karaya gum, xanthine gum, guar bin gum, locust bin gum, carob gum, benzoin gum, homopolysaccharides such as dextran, glucan, levan and succinoglucan and santangum Preferred are microbial mucilages such as hetropolysaccharides, proteins such as glue, gelatin, casein and collagen.

  These water-soluble resins can be used in combination of two or more, and can be contained in the developer in a range of preferably 1 to 50% by mass, more preferably 3 to 30% by mass.

  In addition to the above desensitizing agent, the developer used in the present invention includes a pH adjuster, surfactant, preservative, antifungal agent, lipophilic substance, wetting agent, chelating agent, antifoaming agent and the like. It can be contained.

  The developer is used in the range of pH 3-9. Therefore, generally a pH adjuster is added. In order to adjust the pH to 3 to 9, generally, a mineral acid, an organic acid, an inorganic salt, or the like is added and adjusted in the developer. The addition amount is 0.01-2 mass%. For example, the mineral acid includes nitric acid, sulfuric acid, phosphoric acid, metaphosphoric acid, and the like. Examples of the organic acid include acetic acid, succinic acid, malonic acid, p-toluenesulfonic acid, levulinic acid, phytic acid, organic phosphonic acid, and amino acids such as glycine, α-alanine, and β-alanine. Inorganic salts include magnesium nitrate, primary sodium phosphate, secondary sodium phosphate, nickel sulfate, sodium hexametaphosphate, sodium tripolyphosphate, and the like. You may use together at least 1 sort (s) or 2 or more types, such as a mineral acid, an organic acid, or an inorganic salt.

  Examples of the surfactant contained in the developer include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, α-olefin sulfonates, dialkyl sulfosuccinates, alkyl diphenyl ether disulfonates, linear alkyl benzene sulfonates, branched Chain alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, sodium N-methyl-N-oleyl taurate, disodium N-alkylsulfosuccinate monoamide Salts, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate esters, alkyl sulfate esters, polyoxy Ethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene Examples thereof include alkyl phenyl ether phosphate esters, saponification products of styrene-maleic anhydride copolymers, partial saponification products of olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates. Among these, dialkyl sulfosuccinates, alkyl sulfate esters, alkyl naphthalene sulfonates, α-olefin sulfonates, and alkyl diphenyl ether disulfonates are particularly preferably used.

  As the cationic surfactant, alkylamine salts, quaternary ammonium salts and the like are used.

  As the amphoteric surfactant, alkyl carboxybetaines, alkyl imidazolines, alkylaminocarboxylic acids and the like are used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial esters, sorbitan fatty acid partial esters , Pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters , Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanol Mido, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamine, triethanolamine fatty acid ester, trialkylamine oxide, polypropylene glycol molecular weight 200-5000, trimethylolpropane, glycerin or sorbitol poly Examples include adducts of oxyethylene or polyoxypropylene, and acetylene glycols. Fluorine-based and silicon-based nonionic surfactants can also be used in the same manner.

  Two or more surfactants can be used in combination. The amount used is not particularly limited, but a preferable range is 0.01 to 20% by mass, preferably 0.05 to 10% by mass based on the total mass of the developer.

As the preservative, known materials used in the fields of fiber, wood processing, food, medicine, cosmetics, agricultural chemicals and the like can be used. For example, quaternary ammonium salts, monohydric phenol derivatives, dihydric phenol derivatives, polyhydric phenol derivatives, imidazole derivatives, pyrazolopyrimidine derivatives, monohydric naphthols, carbonates, sulfone derivatives, organotin compounds, cyclopentane derivatives, phenyl derivatives , Phenol ether derivatives, phenol ester derivatives, hydroxylamine derivatives, nitrile derivatives, naphthalenes, pyrrole derivatives, quinoline derivatives, benzothiazole derivatives, secondary amines, 1,3,5 triazine derivatives, thiadiazole derivatives, anilide derivatives, pyrrole derivatives , Halogen derivatives, dihydric alcohol derivatives, dithiols, cyanic acid derivatives, thiocarbamic acid derivatives, diamine derivatives, isothiazole derivatives, monohydric alcohols, saturated aldehydes, Japanese monocarboxylic acid, saturated ether, unsaturated ether, lactone, amino acid derivative, hydantoin, cyanuric acid derivative, guanidine derivative, pyridine derivative, saturated monocarboxylic acid, benzenecarboxylic acid derivative, hydroxycarboxylic acid derivative, biphenyl, hydroxamic acid derivative , Aromatic alcohols, halogenophenol derivatives, benzenecarboxylic acid derivatives, mercaptocarboxylic acid derivatives, quaternary ammonium salt derivatives, triphenylmethane derivatives, hinokitiol, furan derivatives, benzofuran derivatives, acridine derivatives, isoquinoline derivatives, arsine derivatives, thiocarbamine Acid derivatives, phosphate esters, halogenobenzene derivatives, quinone derivatives, benzenesulfonic acid derivatives, monoamine derivatives, organophosphate esters, piperazine derivatives , Phenazine derivatives, pyrimidine derivatives, thiophanate derivatives, imidazoline derivatives, isoxazole derivatives, known preservatives such as ammonium salt derivatives can be used. Particularly preferred preservatives include pyridinethiol-1-oxide salts, salicylic acid and its salts, 1,3,5-trishydroxyethylhexahydro-S-triazine, 1,3,5-trishydroxymethylhexahydro-S- Examples include triazine, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, and 2-bromo-2-nitro-1,3-propanediol. A preferred addition amount 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 The range of 4% by mass is preferable, and it is preferable to use two or more preservatives in combination so as to be effective against various molds and bacteria.

  The developer may contain a lipophilic substance. Preferred lipophilic substances include organic carboxylic acids having 5 to 25 carbon atoms such as oleic acid, lanolinic acid, valeric acid, nonylic acid, capric acid, myristic acid, palmitic acid, castor oil and the like. These lipophilic substances can be used alone or in combination of two or more. The lipophilic substance contained in the developer is in the range of 0.005 to 10% by mass, more preferably 0.05 to 5% by mass, based on the total mass.

  In addition, glycerin, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, diglycerin, etc. may be added to the developer as necessary. it can. These wetting agents may be used alone or in combination of two or more. The preferred use amount of these wetting agents is 0.1 to 5% by mass.

  Further, a chelate compound may be added to the developer. Usually, the developer is usually marketed as a concentrated solution, and is used after being diluted by adding tap water, well water or the like at the time of use. Calcium ions contained in the diluted tap water and well water may adversely affect printing and may cause the printed matter to become dirty. Therefore, the above disadvantages can be eliminated by adding a chelate compound. . Preferred chelate compounds include, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, hydroxyethylethylenediaminetrimethyl Acetic acid, potassium salt, sodium salt; nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium Examples thereof include organic phosphonic acids such as salts and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents. These chelating agents are selected so that they exist stably in the developer composition and do not impair the printability. The addition amount is suitably 0.001 to 1.0% by mass with respect to the developer at the time of use.

  Moreover, an antifoamer can also be added to a developing solution, and a silicon antifoamer is especially preferable. Among them, an emulsified dispersion type and a solubilized type can be used. Preferably, the range of 0.001 to 1.0% by mass with respect to the developing solution at the time of use is optimal.

  The developer may be prepared as an emulsified dispersion type, an organic solvent is used as the oil phase, and it may be made into a solubilized type (emulsified type) with the aid of a surfactant as described above. .

  The organic solvent is preferably an organic solvent having a solubility in water at 20 ° C. of 5% by mass or less and a boiling point of 160 ° C. or more. For example, phthalic acid diester agents such as dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, butyl benzyl phthalate, etc. , Aliphatic dibasic esters such as butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl sebacate, for example, epoxidized triglycerides such as epoxidized soybean oil, The freezing point of phosphoric acid esters such as cresyl phosphate, trioctyl phosphate, trischlor ethyl phosphate, for example, benzoic acid esters such as benzyl benzoate is 15 ° C. or less, Boiling point at atmospheric pressure include 300 ° C. or more plasticizers.

  Examples of other alcohols include 2-octanol, 2-ethylhexanol, nonanol, n-decanol, undecanol, n-dodecanol, trimethylnonyl alcohol, tetradecanol, and benzyl alcohol. Examples of glycols include ethylene glycol isoamyl ether, ethylene glycol monophenyl ether, ethylene glycol benzyl ether, ethylene glycol hexyl ether, and octylene glycol.

  Odor is particularly mentioned as a condition when selecting the compound. A preferable range of the amount of these solvents used is 0.1 to 5% by mass of the plate surface protecting agent, and a more preferable range is 0.5 to 3% by mass. These solvents can be used alone or in combination of two or more.

  The developer used in the present invention is prepared by preparing a water phase at a temperature of 40 ° C. ± 5 ° C., stirring at high speed, slowly dropping the prepared oil phase into the water phase, stirring sufficiently, and then emulsifying and dispersing through a pressure type homogenizer. It is produced by doing.

  The remaining component of the developer is water. It is advantageous in terms of transportation that the developer is a concentrated solution having a water content less than that in use and is diluted with water when in use. In this case, the degree of concentration is appropriate such that each component does not cause separation or precipitation.

  In the present invention, the development treatment with a developer having a pH of 3 to 9 can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs rubbing while conveying a lithographic printing original plate after image recording, Automatic processing for rubbing the lithographic printing original plate after image recording set on the cylinder described in the specifications of US Pat. No. 5,148,746, US Pat. No. 5,568,768 and British Patent No. 2,297,719, while rotating the cylinder Machine. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable. In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water, dried and desensitized.

  When the developing solution of the present invention is a gum solution, as a plate making method, a single processing of the gum solution, a two-step process of gum solution (development) / gum solution (desensitization), or development treatment with a gum solution / washing with water / Desensitizing treatment with gum solution can be selected as necessary. The gum solution used for development and the gum solution used for desensitization may be the same or different.

  Although the developing solution in this invention can be used at arbitrary temperature, Preferably it is 10 to 50 degreeC, More preferably, it is 20 to 40 degreeC.

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

  In this example, the effect of the compound of the present invention is verified for the lithographic printing plate precursors (I) to (III) having different types of image recording layers.

[I] Preparation of planographic printing plate precursor (I) type [Example 1]
(1) Preparation of support In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) having a thickness of 0.3 mm, degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution. After that, the aluminum surface was grained using ^three bundle-planted nylon brushes having a bristle diameter of 0.3 mm and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed thoroughly with water. . This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode.
The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying.
Next, the plate was provided with a DC anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolyte, and then washed with water. It dried and produced the support body (1).
Then, in order to ensure the hydrophilic property of a non-image part, the support (1) was subjected to silicate treatment at 70 ° C. for 12 seconds using a 1.5 mass% No. 3 sodium silicate aqueous solution. The adhesion amount of Si was 6 mg / m ² . Then, it washed with water and the support body (2) was obtained. The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

On the support (2), the following undercoat liquid (1) was applied so that the dry coating amount was 20 mg / m ² to prepare a support used in the following experiments.

<Undercoat liquid (1)>
・ The following undercoat compound (1) 0.18 g
・ DABCO 0.12g
・ Methanol 55.24g
・ Distilled water 6.15g

(2) Formation of image recording layer The above support having an undercoat layer was bar-coated with an image recording layer coating solution (1) having the following composition, and then oven-dried at 100 ° C for 60 seconds to obtain a dry coating amount of 1.0 g / An m ² image recording layer was formed.
The image recording layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microgel solution (1) immediately before coating.

<Photosensitive solution (1)>
-Binder polymer (1) [the following structure] 0.240 g
Infrared absorber (1) [the following structure: component (A)] 0.030 g
-Polymerization initiator (1) [the following structure: (B) component] 0.162g
・ Polymerizable compound [component (C)]
Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Tris (2-hydroxyethyl) isocyanurate 0.062g
・ Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
-Compound (1) of the present invention
(Viewlight ESS, Sanyo Chemical Industries, Ltd.) 0.055g
・ Fluorosurfactant (1) [The following structure] 0.008g
・ Methyl ethyl ketone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microgel solution (1)>
-Microgel (1) [the following synthesis method] 2.640 g
・ Distilled water 2.425g

(Synthesis of microgel (1))
As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemical Co., Ltd., Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd., SR444) 3.15 g, And 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 50 ° C. for 3 hours. The solid content concentration of the microgel solution thus obtained was diluted with distilled water so as to be 15% by mass. The average particle size was 0.2 μm.

(3) Formation of Protective Layer After the protective layer coating solution (1) having the following composition was further bar coated on the image recording layer, it was oven-dried at 120 ° C. for 60 seconds, and the dry coating amount was 0.15 g / m ² A lithographic printing plate precursor of Example 1 was obtained.

<Protective layer coating solution (1)>
-1.5 g of inorganic layered compound dispersion (1) prepared as follows
・ Polyvinyl alcohol (Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modified,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
・ Polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd., saponification degree: 81.5 mol%,
Polymerization degree 500) 6% by mass aqueous solution 0.03 g
・ Nippon Emulsion Co., Ltd. surfactant (Emalex 710),
1 mass% aqueous solution 8.60g
・ Ion-exchanged water 6.0g

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

[Examples 2 to 11 and Comparative Examples 1 to 5]
Except that the compound (1) of the present invention contained in the photosensitive solution (1) of the lithographic printing plate precursor of Example 1 was changed to the compounds shown in Table 2, Examples 2 to 11 and The planographic printing plate precursors of Comparative Examples 1 to 5 were prepared.

[Example 12]
A lithographic printing plate precursor 12 was produced in the same manner as in Example 1 except that the undercoat liquid (1) used in Example 1 was replaced with the following undercoat liquid (2).

<Undercoat liquid (2)>
-0.18 g of the above-mentioned undercoat compound (1)
・ DABCO 0.12g
-Compound (1) of the present invention 0.05 g
・ Methanol 55.24g
・ Distilled water 6.15g

[Example 13]
Lithographic printing was carried out in the same manner as in Example 1 except that the undercoat liquid (1) used in Example 1 was replaced with the following undercoat liquid (3) and a photosensitizer obtained by removing the compound of the present invention from the photosensitizer (1) was used. A plate precursor 13 was prepared.

<Undercoat liquid (3)>
-0.18 g of the above-mentioned undercoat compound (1)
・ DABCO 0.12g
-Compound (1) of the present invention 0.10 g
・ Methanol 55.24g
・ Distilled water 6.15g

[II] Preparation of planographic printing plate precursor (II) mold [Example 14]
A lithographic printing plate precursor of Example 14 was obtained in the same manner as in Example 1 except that the image recording layer coating liquid (1) was changed to the following image recording layer coating liquid (2).

<Image recording layer coating solution (2)>
・ 0.50 g of the above binder polymer (1)
・ The following infrared absorber (2) 0.05 g
・ 0.20g of the above polymerization initiator (1)
Polymerizable compound, Aronix M-215 (manufactured by Toa Gosei Co., Ltd.) 1.00 g
-Compound (1) of the present invention (view light ESS, manufactured by Sanyo Chemical Industries, Ltd.) 0.05 g
・ 0.10 g of the above-mentioned fluorosurfactant (1)
・ Methyl ethyl ketone 18.0 g

[Examples 15 to 18 and Comparative Examples 6 to 10]
Examples 15 to 18 and Comparative Examples 6 to 10 were the same as Example 14 except that the compound (1) of the present invention contained in the image recording layer coating solution (2) was changed to the compounds shown in Table 3. A lithographic printing plate precursor was prepared.

[III] Preparation of lithographic printing plate precursor (III) mold [Example 19]
The following image recording layer coating solution (3) was bar-coated on a support having the same undercoat layer used in Example 1, and then oven-dried at 70 ° C. for 60 seconds, and the dry coating amount was 0.6 g / m. ^Two image recording layers were prepared.

<Image recording layer coating solution (3)>
-Polymer fine particles (hydrophobized precursor) aqueous dispersion prepared as follows: 33.0 g
・ The following infrared absorber (3) 1.0 g
・ Pentaerythritol tetraacrylate 0.5g
-Compound (1) of the present invention (Bulite ESS, Sanyo Chemical Industries, Ltd.) 0.1 g
・ Methanol 16.0g

(Production of polymer fine particle (hydrophobized precursor) aqueous dispersion)
A stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser is applied to a 1000 ml four-necked flask, and 350 mL of distilled water is added while deoxygenating by introducing nitrogen gas, and the internal temperature becomes 80 ° C. Until heated. Add 1.5 g of sodium dodecyl sulfate as a dispersant, 0.45 g of ammonium persulfide as an initiator, then add a mixture of 45.0 g of glycidyl methacrylate and 45.0 g of styrene from a dropping funnel to about 1 It was added dropwise over time. After the completion of the dropping, the reaction was continued as it was for 5 hours, and then the unreacted monomer was removed by steam distillation. Thereafter, the mixture was cooled and adjusted to pH 6 with ammonia water, and finally pure water was added so that the nonvolatile content was 15% by mass to obtain an aqueous dispersion of polymer fine particles (hydrophobized precursor). The particle size distribution of the polymer fine particles had a maximum value at a particle size of 60 nm.

  Here, the particle size distribution is obtained by taking an electron micrograph of polymer fine particles, measuring a total of 5000 fine particle sizes on the photograph, and a logarithmic scale between 0 and the maximum value of the obtained particle size measurement values. The frequency of appearance of each particle size was plotted and divided into 50. For non-spherical particles, the particle size of spherical particles having the same particle area as that on the photograph was used as the particle size.

The following protective layer coating solution (2) is bar-coated on the image recording layer formed as described above, followed by oven drying at 60 ° C. for 120 seconds to form a protective layer having a dry coating amount of 0.3 g / m ^2. Thus, a planographic printing plate precursor of Example 19 was obtained.

<Protective layer coating solution (2)>
・ Carboxymethylcellulose (Mw20,000) 5.0g
・ Water 50.0g

[Examples 20 to 23 and Comparative Examples 11 to 15]
Examples 20 to 23 and Comparative Examples 11 to 15 were carried out in the same manner as in Example 19 except that the compound (1) of the present invention contained in the image recording layer coating solution (3) was changed to the compounds shown in Table 4. A lithographic printing plate precursor was prepared.

[IV] Plate Making The lithographic printing plate precursor obtained as described above is manufactured by Fujifilm Corporation's Luxel PLANETSETTER T-6000III equipped with an infrared semiconductor laser. The outer drum rotation speed is 1000 rpm, the laser output is 70%, and the resolution is 2400 dpi. Exposure was performed under conditions. The exposure image includes a fine line image.
Next, using the automatic developing apparatus shown in FIG. 1, the exposed lithographic printing plate precursor is removed with an unexposed portion of the image recording layer at the developing portion 14 in the figure, and with tap water at the water washing portion 16 in the figure. The desensitization step was performed using the treatment liquid described in Table 1 below in the water washing step, 18 in the figure.
The lithographic printing plate thus made was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) Dampening water and ink were supplied by the standard automatic printing start method of LITHRONE 26, and 100 sheets were printed on Tokuhishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.

<Gum solution 1> pH 4
Gum arabic 1.6% by mass
Enzyme modified potato starch 8.8% by mass
Phosphorylated waxy onion starch 0.80% by mass
Dioctyl sulfosuccinate sodium salt 0.10% by mass
Citric acid 0.14% by mass
α-Alanine 0.11% by mass
EDTA-tetrasodium salt 0.10% by mass
Dodecyl diphenyl ether disulfonic acid 2Na salt 0.18% by mass
Ethylene glycol 0.72% by mass
Benzyl alcohol 0.87% by mass
Sodium dehydroacetate 0.04% by mass
Emulsion type silicon antifoaming agent 0.01% by mass
Add water to make 100% by mass

<Gum solution 2> pH 3.5
FUJIFILM Gum Liquid “FN-6” / Tap Water = 1/1

<Gum solution 3> pH 5
Anionic surfactant (Dowfax 3B2, manufactured by Dow Chemical) 100 ml
1,3-benzenedisulfonic acid 2Na salt 31.25 g
(Riedel de Haan)
Polystyrene sulfonic acid 31.25g
(Versa TL77, made by Alco Chemical)
Trisodium citrate dihydrate 10.4g
Preservative (Aceticide LA1206, manufactured by Thor) 2ml
Polyoxyethylene 2.08g
(Polyox WSRN-750 (manufactured by Union Carbide)
1750g of water

[V] Evaluation (A) Developability In any of the planographic printing plate precursors, there is no stain on the surface of the fifth printed sheet, and the fine line reproducibility reproduces a 10 μm fine line, which indicates that the developability is good. It was.

(B) Pot-like printing stain The obtained lithographic printing plate precursor was left in a constant temperature and humidity chamber set at 50 ° C. and a relative humidity of 75% for 6 days, and then unexposed and having a pH of 3 to 9 as described above. Developed with developer. The number of minute spot stains in the range of 100 cm ² on the 100th printed paper surface was counted. The results are shown in Tables 2-4.

  In the following Tables 2 to 4, the compounds of the present invention are indicated by the numbers of the exemplified compounds in the present specification. The compounds used in the comparative examples are shown below.

  As can be seen from the above evaluation results, according to the present invention, it is possible to achieve both good developability and suppression of spot-like stains in a system using a developer of pH 3-9.

It is a figure which shows the structure of the automatic image development apparatus of the lithographic printing plate precursor concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic developing device 10 Development processing part 12 Planographic printing plate precursor 14 Development part 16 Washing part 18 Desensitizing process part 20 Drying part 24 Developing tank 141,142 Brush roller (rubbing member)
200 Pre-processing section

Claims (8)

A lithographic printing plate precursor having an undercoat layer and an image recording layer on a support and developable with a developer having a pH of 3 to 9, wherein the undercoat layer and / or the image recording layer is represented by the following general formula (1) A lithographic printing plate precursor comprising a represented compound.

Here, X ⁺ ₁ and X ⁺ ₂ may be the same or different and represent H ⁺ or a monovalent cationic group. Instead of X ⁺ ₁ and X ⁺ ₂ , one divalent cationic group may be used.   The lithographic printing plate precursor as claimed in claim 1, wherein the developer is a gum solution.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the compound having the structure represented by the general formula (1) according to claim 1 has a polyoxyethylene group or a polyoxypropylene group in the molecule. .   The lithographic plate according to any one of claims 1 to 3, wherein the image recording layer contains (A) an infrared absorber, (B) a polymerization initiator, and (C) a polymerizable compound. A printing plate master.   The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the image recording layer contains microcapsules and / or microgels.   The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the image recording layer contains (A) an infrared absorber and (D) a hydrophobized precursor.   A lithographic printing plate precursor according to any one of claims 1 to 6, wherein the lithographic printing plate precursor is imagewise exposed with an infrared laser and then developed with a developer having a pH of 3 to 9.   The plate making method according to claim 7, wherein the developer is a gum solution.