JP2005215147A - Polymerizable composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymerizable composition which is polymerized and cured with high sensitivity by exposure and heating and has good preservability (raw preservability), and to further provide a polymerizable composition capable of performing high sensitivity recording with an infrared laser, excellent in preservability (raw preservability) and printing durability, and useful as a recording layer of a negative lithographic printing plate original plate. <P>SOLUTION: The polymerizable composition contains (A) a radical initiator represented by formula (1), (B) an ethylenically unsaturated compound and (C) an infrared absorbent. In the formula (1), X represents carbonyl group, sulfone group or sulfoxide group; Y represents alkyl group, alkenyl group, alkynyl group, aryl group, benzoyl group or a heterocyclic group; Q and Z each independently represents a monovalent substituent comprising nonmetallic atoms and these may have a substituent containing one or more atoms selected from the group consisting of hydrogen atom, oxygen atom, halogen atom, nitrogen atom, and sulfur atom. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polymerizable composition, and more particularly to a polymerizable composition useful as a negative image recording layer of a lithographic printing plate precursor.

Conventionally, as a lithographic printing plate precursor, one having a constitution in which a lipophilic photosensitive resin layer is provided on a hydrophilic support is widely used. As the plate making method, usually, a method of obtaining a desired printing plate by dissolving and removing a non-image portion after mask exposure (surface exposure) through a lithographic film has been used.
In recent years, digitization techniques that electronically process, store, and output image information using a computer have become widespread. Various new image output methods corresponding to such digitization techniques have come into practical use. As a result, computer-to-plate (CTP) technology that scans highly directional light such as laser light according to digitized image information and directly produces a printing plate without going through a lithographic film is eagerly desired. Therefore, obtaining a lithographic printing plate precursor adapted to this is an important technical issue.

  As such a lithographic printing plate precursor capable of scanning exposure, an oleophilic photosensitive resin layer containing a photosensitive compound capable of generating active species such as radicals and Bronsted acid by laser exposure on a hydrophilic support (hereinafter referred to as “lithographic printing plate precursor”) , Also referred to as “photosensitive layer”) has been proposed and is already on the market. This lithographic printing plate precursor is subjected to laser scanning exposure based on digital information to generate active species, which causes physical or chemical changes in the photosensitive layer to insolubilize it, followed by development processing, thereby developing negative lithographic printing You can get a version.

  As a negative lithographic printing plate precursor, light containing a photopolymerization initiator excellent in photosensitive speed, an ethylenically unsaturated compound capable of addition polymerization, and a binder polymer soluble in an alkali developer on a hydrophilic support. A polymerization-type photosensitive layer and an oxygen-blocking protective layer as necessary are known (for example, see Patent Document 1). Such a lithographic printing plate precursor has desirable printing performance from the advantages that it is excellent in productivity, is easy to develop, and has good resolution and inking properties.

Examples of the binder polymer include alkali development such as methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer, and partially esterified maleic acid copolymer. Possible organic polymer polymers are used (for example, refer to Patent Documents 2 to 9).
Furthermore, a technique for incorporating a polyurethane resin having an allyl group as a binder polymer into a photosensitive layer in order to improve coating properties, stability over time, printing durability, and the like has been disclosed (see Patent Document 10).

Various attempts have been made to improve the sensitivity of these recording materials as described above. However, compounds added for the purpose of improving sensitivity tend to be decomposed by a small amount of energy or cause an undesirable effect reaction, and there is a concern about stability, so high sensitivity recording is possible. The present situation is that a polymerizable composition that is excellent in storage stability (raw storage stability) and can be applied to a negative type lithographic printing plate precursor has not been obtained.
Japanese Patent Laid-Open No. 10-195119 JP 59-44615 Japanese Patent Publication No.54-34327 Japanese Examined Patent Publication No. 58-12777 Japanese Patent Publication No.54-25957 JP 54-92723 A JP 59-53836 A JP 59-71048 A JP 2002-40652 A Japanese Patent No. 2712564

An object of the present invention is to solve the conventional problems and achieve the following objects.
That is, a first object of the present invention is to provide a polymerizable composition that is polymerized and cured with high sensitivity by exposure and heating and that has good storage stability (raw storage stability).
The second object of the present invention is a polymerization useful as a recording layer for a negative lithographic printing plate precursor, capable of high-sensitivity recording with an infrared laser, and excellent in storage stability (raw storage) and printing durability. It is to provide a sex composition.

As a result of intensive studies, the present inventor has found that the above problem can be solved by using an oxime derivative having a specific structure as a polymerization initiator, and has completed the present invention.
That is, the polymerizable composition of the present invention contains (A) a radical initiator represented by the following general formula (1), (B) an ethylenically unsaturated compound, and (C) an infrared absorber. It is characterized by.

In the general formula (1), X represents a carbonyl group, a sulfone group, or a sulfoxide group, and Y represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a benzoyl group, or a heterocyclic group.
Q and Z each independently represent a monovalent substituent consisting of a nonmetallic atom, and these are one or more selected from the group consisting of a hydrogen atom, an oxygen atom, a halogen atom, a nitrogen atom, and a sulfur atom You may have a substituent containing an atom.

  The polymerizable composition preferably further contains (D) a binder polymer having an ethylenically unsaturated double bond in the molecule, from the viewpoint of sensitivity and formed film strength. Further, as the infrared absorber (C) used here, a cyanine dye is preferable.

  The polymerizable composition of the present invention is cured with high sensitivity by applying energy such as exposure and heating, and has an effect of being excellent in storage stability, that is, storage stability before energy application. Therefore, the polymerizable composition of the present invention is useful as a recording layer of a negative lithographic printing plate precursor that performs image recording directly from an infrared laser.

Hereinafter, the present invention will be described in detail.
[Polymerizable composition]
The polymerizable composition of the present invention contains (A) a radical initiator represented by the following general formula (1), (B) an ethylenically unsaturated compound, and (C) an infrared absorber, And (D) a binder polymer having an ethylenically unsaturated double bond in the molecule.
Hereinafter, each component contained in the polymerizable composition will be sequentially described.
First, (A) the radical initiator represented by the general formula (1), which is a characteristic component of the present invention, will be described.
[(A) Radical initiator represented by general formula (1)]
The radical initiator used in the present invention is an oxime derivative represented by the following general formula (1).

In the general formula (1), X represents a carbonyl group, a sulfone group, or a sulfoxide group. Y represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a benzoyl group, or a heterocyclic group, and more specifically, a cyclic or chain alkyl group having 1 to 12 carbon atoms, an alkenyl group, or an alkynyl group. Represents an aryl group having 6 to 18 carbon atoms or a heterocyclic group.
Q and Z each independently represent a monovalent substituent consisting of a nonmetallic atom, and these are one or more selected from the group consisting of a hydrogen atom, an oxygen atom, a halogen atom, a nitrogen atom, and a sulfur atom You may have a substituent containing an atom.

When Y represents an aryl group, the aryl group is preferably an aromatic hydrocarbon compound such as a benzene ring, naphthalene ring, anthracene ring, phenanthrene group, pyrene group, triphenylene group, and the heterocyclic group is a nitrogen atom. Aromatic compounds having at least one hetero atom selected from sulfur atom and oxygen atom in the ring structure, such as pyrrole group, furan group, thiophene group, selenophene group, pyrazole group, imidazole group, triazole group, tetrazole Group, oxazole group, thiazole group, indole group, benzofuran group, benzimidazole group, benzoxazole group, benzothiazole group, pyridine group, pyrimidine group, pyrazine group, triazine group, quinoline group, carbazole group, acridine group, phenoxazine, Phenothiazine, etc. Compounds.
The substituent represented by Y is a halogen atom, hydroxyl group, nitrile group, nitro group, carboxyl group, aldehyde group, alkyl group, thiol group, aryl group, alkenyl group, alkynyl group, ether group, ester group, urea group, One or more substitutions selected from amino group, amide group, sulfide group, disulfide group, sulfoxide group, sulfo group, sulfone group, hydrazine group, carbonyl group, imino group, urethane group, phosphoroso group, phospho group, carbonyl ether group It may be substituted by a group.

  In the general formula (1), Q and Z each independently represent a monovalent substituent composed of a nonmetallic atom, preferably a nitrile group, a halogen atom, a hydrogen atom, an amino group, and Y as described above. Organic groups. The substituent represented by Z is a halogen atom, hydroxyl group, nitrile group, nitro group, carboxyl group, aldehyde group, alkyl group, thiol group, aryl group or alkenyl group, alkynyl group, ether group, ester group, urea group, Amino group, amide group, sulfide group, disulfide group, sulfoxide group, sulfo group, sulfone group, hydrazine group, carbonyl group, imino group, halogen atom, hydroxyl group, nitrile group, nitro group, carboxyl group, carbonyl group, urethane group, It may be further substituted with a substituent including an alkyl group, a thiol group, an aryl group, a phosphoroso group, a phospho group, and a carbonyl ether group.

  As a more preferred embodiment of the radical initiator represented by the general formula (1), a compound represented by the following general formula (2) is exemplified.

In the general formula (2), X represents a carbonyl group, a sulfone group, or a sulfoxide group, and a carbonyl group is preferable from the viewpoint of sensitivity.
Y represents a cyclic or chain alkyl group having 1 to 12 carbon atoms, an alkenyl group, an alkynyl group, an aryl group having 6 to 18 carbon atoms, or a heterocyclic group, and is represented by the general formula (1). Although it is synonymous, from the viewpoint of sensitivity, an aryl group or a benzoyl group is preferable, and a halogen atom, a nitrile group, a nitro group, an aryl group, a hydroxyl group, an alkyl group, a thiol group, a carboxyl group, an ether group is particularly preferable. An aryl group or a benzoyl group which may be substituted with a substituent selected from
Z has the same meaning as in the general formula (1), and preferably an alkyl group or an aryl group from the viewpoint of sensitivity, and particularly preferably a halogen atom, a nitrile group, a nitro group, an aryl group, Examples thereof include an alkyl group or an aryl group which may be substituted with a substituent selected from a hydroxyl group, an alkyl group, a thiol group, a carboxyl group, and an ether group.
n represents an integer of 0 or 1.

V represents a cyclic or chain alkyl group having 1 to 12 carbon atoms, an alkenyl group, an alkynyl group, an aryl group having 6 to 18 carbon atoms, an alkoxy group, or an aryloxy group, where the aryl group is a benzene ring. , Aromatic hydrocarbon compounds such as naphthalene ring, anthracene ring, phenanthrene group, pyrene group, triphenylene group, pyrrole group, furan group, thiophene group, selenophene group, pyrazole group, imidazole group, triazole group, tetrazole group, oxazole group, Heteroatom such as thiazole group, indole group, benzofuran group, benzimidazole group, benzoxazole group, benzothiazole group, pyridine group, pyrimidine group, pyrazine group, triazine group, quinoline group, carbazole group, acridine group, phenoxazine, phenothiazine Aromatization Things. Among them, the aryl group is preferable.
Substituents represented by V are halogen atoms, hydroxyl groups, nitrile groups, nitro groups, carboxyl groups, aldehyde groups, alkyl groups, thiol groups, aryl groups or alkenyl groups, alkynyl groups, ether groups, ester groups, urea groups, Amino group, amide group, sulfide group, disulfide group, sulfoxide group, sulfo group, sulfone group, hydrazine group, carbonyl group, imino group, halogen atom, hydroxyl group, nitrile group, nitro group, carboxyl group, carbonyl group, urethane group, It may have one or more substituents selected from the group consisting of an alkyl group, a thiol group, an aryl group, a phosphoroso group, a phospho group, and a carbonyl ether group.
V and Z may be bonded to each other to form a ring.

A preferable radical initiator used in the present invention is a compound represented by the general formula (2) from the viewpoint of sensitivity, wherein X is a carbonyl group, Y is an aryl group or benzoyl group, and Z group is an alkyl group or Preferred examples include an aryl group, W is a carbonyl group, and V is an aryl group. More preferred is a compound in which V is an aryl group having a thioether substituent.
Note that the structure of the N—O bond in the general formula (1) or the general formula (2) may be E-form or Z-form.

  In addition, examples of oxime derivatives that can be suitably used as radical initiators in the present invention include “Progress in Organic Coatings”, Vol. 13 (1985) p123-150; "JC S Perkin II", (1979), p1653-1660; "Journal of Photoscience Science and Technology" (1995) p205-232; "JC Perkin II". (1979) p156-162; JP-A 2000-66385; JP-A 2000-80068.

  Specific examples of the radical initiator represented by the general formula (1) preferably used in the present invention [Exemplary compounds (OS-1) to (OS-99)] are shown below, but the present invention is not limited thereto. It is not something.

In addition to the specific radical initiator, other known radical initiators can be used in combination with the polymerizable composition of the present invention as long as the effects of the present invention are not impaired. The total content of the polymerization initiator with respect to the polymerizable composition is 0.1 to 50% by mass, preferably 0.5 to 30%, based on the total solid content, from the viewpoint of balance between sensitivity and removability in the uncured region. It is in the range of 1% to 20% by mass, particularly preferably 1% by mass. When the content of the radical initiator in the polymerizable composition is too large, in the image forming material using this polymerizable composition as a recording layer, the removability in the non-image area decreases, and the non-image area is not printed during printing. There is a tendency for contamination to occur easily.
The content of the radical initiator represented by the general formula (1) in the present invention with respect to the total weight of the radical initiator is 50 to 100% by weight, more preferably 75 to 95% by weight.

  Other radical initiators that can be used in combination include onium salts such as sulfonium, iodonium and diazonium, triazine compounds having a trihalomethyl group, peroxides, azo polymerization initiators, azide compounds, quinonediazides, and triarylmonoalkylborate compounds. Of these, sulfonium salts are preferred.

[(B) ethylenically unsaturated compound]
The ethylenically unsaturated compound used in the polymerizable composition of the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least 1, preferably 2 ethylenically unsaturated bonds. It is selected from the compounds having the above. 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, that is, 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 monofunctional or polyfunctional 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 In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. 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.

  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 aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, JP-A-59-5241. Those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. 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.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane 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 (3) to a polyisocyanate compound having two or more isocyanate groups. Compounds and the like.

^{_{CH 2 = C (R 1)}} COOCH 2 CH (R 2) OH (3)
(However, R ¹ and R ² each independently represent H or CH _3. )

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable. Further, by using 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, It is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337 and JP-B-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like can also 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 ethylenically unsaturated compounds, the details of usage, such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the final performance design. For example, it is selected from the following viewpoints. From the viewpoint of photosensitive speed, a structure having a high unsaturated group content per molecule is preferable. Further, in order to increase the strength of the image portion, 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 ester, methacrylic ester, styrenic compound, A method of adjusting both photosensitivity and strength by using a vinyl ether compound) is also effective. A compound having a large molecular weight or a compound having high hydrophobicity is excellent in photosensitive speed and film strength, but is not preferable in terms of development speed and precipitation in a developer. In addition, the selection and use method of the addition polymerization compound is also an important factor for the compatibility and dispersibility with other components (for example, binder polymer, initiator, colorant, etc.) in the polymerizable composition. For example, the compatibility may be improved by using a low-purity compound or using two or more kinds in combination.
In the lithographic printing plate precursor according to the invention, a specific structure may be selected for the purpose of improving the adhesion of a support or a protective layer described later.

Regarding the content of the ethylenically unsaturated compound in the polymerizable composition, from the viewpoint of sensitivity, occurrence of phase separation, adhesiveness of the photosensitive layer, and precipitation from the developer, the solid content in the polymerizable composition. Preferably, it is used in the range of 5 to 80% by mass, more preferably 40 to 75% by mass with respect to the minute.
These may be used alone or in combination of two or more. In addition, as for the method of using the ethylenically unsaturated compound, an appropriate structure, blending, and addition amount can be arbitrarily selected from the viewpoints of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface tackiness, and the like. In addition, when the polymerizable composition of the present invention is used as a recording layer for a lithographic printing plate precursor or the like, it is possible to carry out a layer configuration / coating method such as undercoating or overcoating.

[(C) Infrared absorber]
The polymerizable composition of the present invention contains an infrared absorbent for the purpose of developing an energy transfer function (electron transfer), a photothermal conversion function, and the like.
Infrared absorbers are in an electronically excited state with high sensitivity to infrared laser irradiation (exposure), and the electron transfer, energy transfer, heat generation (photothermal conversion function), etc. associated with the electron excited state act on the radical initiator. Thus, it is useful for generating a radical by causing a chemical change in the radical initiator with high sensitivity.
The infrared absorber used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm, and among these, a cationic dye is preferable.

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.
Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, 58-181690, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59- No. 73996, JP-A-60-52940, JP-A-60-63744 and the like, Naphthoquinone dyes described in JP-A-58-112792, etc., British Patent 434,875 And cyanine dyes.

Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are 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 in the present invention include specific indolenine cyanine dyes described in Japanese Patent Application Nos. 2001-6326 and 2001-237840 described below.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (a).

In formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. Here, the hetero atom represents N, S, O, a halogen atom, or Se. X _a ^- is defined in the same manner as Z ^1- described later, and R ^a represents a substituent selected from a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, and a halogen atom.

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

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Z ¹⁻ represents a counter anion. However, when the cyanine dye represented by the general formula (a) has an anionic substituent in its structure and charge neutralization is not necessary, Z ¹⁻ is not necessary. Preferred Z ¹⁻ is halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, and sulfonate ion, particularly preferably perchlorate ion, in view of storage stability of the photosensitive layer coating solution. Hexafluorophosphate ions and aryl sulfonate ions.

Specific examples of the cyanine dye represented by formula (a) 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 Japanese Patent Application Nos. 2001-6326 and 2001-237840 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 Applications 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 preferred particle size range, excellent dispersion stability of the pigment in the polymerizable composition can be obtained, and a uniform composition 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 are 0.01-50 mass% with respect to the total solid which comprises a polymeric composition from the viewpoint of the uniformity in polymeric composition, and the durability of the formed film | membrane, Preferably it is 0. 0.1 to 10% by mass, particularly preferably in the case of a dye, 0.5 to 10% by mass, and particularly preferably in the case of a pigment, 0.1 to 10% by mass.
In the case of using the polymerizable composition of the present invention as a photosensitive layer of a lithographic printing plate precursor, the infrared absorber is not necessarily contained in the polymerizable composition and forms the same layer as other components. For example, the same effect can be obtained by adding to another layer provided adjacent to the photosensitive layer made of the polymerizable composition.

[Binder polymer]
The polymerizable composition of the present invention preferably contains a binder polymer from the viewpoint of improving film properties. Various binder polymers can be used as long as they have a function of improving film properties. Especially, the binder polymer which has the group which has an ethylenically unsaturated double bond in the molecule | numerator mentioned later, and / or an alkali-soluble group in a molecule | numerator can be used conveniently.

  As these two preferred groups, those having the same component in the same molecule as the copolymer component may be used, or two or more kinds of binders independently possessed may be used in combination. In addition to a group having a saturated double bond, a binder polymer that further contains a structural unit having an alkali-soluble group as a copolymerization component is preferred.

[(D) Binder polymer having an ethylenically unsaturated double bond in the molecule]
The group having an ethylenically unsaturated double bond is not particularly limited as long as it is a group that can be polymerized by a radical, but an α-substituted methylacryl group [—OC (═O) —C (—CH ₂ Z ) = CH ₂ , Z = hydrocarbon group starting from a hetero atom], acryl group, methacryl group, allyl group, and styryl group, among which acryl group and methacryl group are preferable.
The content of ethylenically unsaturated double bonds in the binder polymer (content of unsaturated double bonds capable of radical polymerization by iodometric titration) is 1 g of binder polymer from the viewpoint of compatibility between sensitivity and storage stability. Preferably it is 0.1-10.0 mmol, More preferably, it is 1.0-7.0 mmol, Most preferably, it is 2.0-5.5 mmol.

  The alkali-soluble group contained in the binder polymer is preferably an alkali-soluble group selected from the group consisting of the following (1) to (6) from the viewpoint of solubility of the binder polymer in an alkaline developer. A binder polymer having a structural unit containing at least one of the alkali-soluble groups mentioned in the above is preferable.

(1) Phenolic hydroxyl group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )

  In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrogen atom or a hydrocarbon group which may have a substituent.

  The structural unit having an alkali-soluble group (acidic group) selected from the above (1) to (6) does not need to be only one type, and has two or more types having the same acidic group and different from each other. It may be a copolymer of structural units, or may be a copolymer of two or more structural units having different acidic groups.

  The content of alkali-soluble groups in the binder polymer (acid value by neutralization titration) is preferably from 0.1 to 3.0 mmol, more preferably from 1 g of the binder polymer, from the viewpoint of preventing development residue and printing durability. Is 0.2 to 2.0 mmol, most preferably 0.45 to 1.0 mmol.

  As an aspect which introduce | transduces an alkali-soluble group into a binder polymer, the aspect containing the structural unit represented by the following general formula (i) in a polymer is mentioned.

(In General Formula (i), R ¹ represents a hydrogen atom or a methyl group, and R ² is composed of one or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. A represents an oxygen atom or —NR ³ —, R ³ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 1 to 5. )

R ¹ in the general formula (i) represents a hydrogen atom or a methyl group, and a methyl group is particularly preferable.
The linking group represented by R ² in the general formula (i) is composed of one or more atoms selected from the group consisting of a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. The number of atoms excluding substituents is preferably 2 to 82. Specifically, the number of atoms constituting the main skeleton of the linking group represented by R ² is preferably 1 to 30, more preferably 3 to 25, and further preferably 4 to 20. Preferably, it is 5-10. The “main skeleton of the linking group” in the present invention refers to an atom or an atomic group used only for linking A and the terminal COOH in the general formula (i), and particularly when there are a plurality of linking paths. Refers to an atom or atomic group that constitutes a path with the least number of atoms used. Therefore, when a linking group has a ring structure, the number of atoms to be included differs depending on the linking site (for example, o-, m-, p-, etc.).

More specific examples include alkylene, substituted alkylene, arylene, substituted arylene, and the like, and a structure in which a plurality of these divalent groups are linked by an amide bond or an ester bond may be used.
Examples of the linking group having a chain structure include ethylene and propylene. A structure in which these alkylenes are linked via an ester bond can also be exemplified as a preferable example.

Among these, the linking group represented by R ² in the general formula (i) is preferably an (n + 1) -valent hydrocarbon group having an aliphatic cyclic structure having 3 to 30 carbon atoms. More specifically, a compound having an aliphatic cyclic structure such as cyclopropane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, dicyclohexyl, tercyclohexyl, norbornane and the like, which may be substituted by one or more arbitrary substituents And (n + 1) valent hydrocarbon groups by removing (n + 1) hydrogen atoms on an arbitrary carbon atom constituting. R ² preferably has 3 to 30 carbon atoms including a substituent.

One or more arbitrary carbon atoms of the compound constituting the aliphatic cyclic structure may be replaced with a heteroatom selected from a nitrogen atom, an oxygen atom, or a sulfur atom. In terms of printing durability, R ² represents a condensed polycyclic aliphatic hydrocarbon, a bridged cyclic aliphatic hydrocarbon, a spiro aliphatic hydrocarbon, an aliphatic hydrocarbon ring assembly (a plurality of rings are connected by a bond or a linking group). A (n + 1) valent hydrocarbon group having an aliphatic cyclic structure which may have a substituent of 5 to 30 carbon atoms containing two or more rings. . Also in this case, the carbon number includes the carbon atom of the substituent.

As the linking group represented by R ² , those having 5 to 10 atoms constituting the main skeleton of the linking group are particularly preferable. And those having a cyclic structure as described above are preferred.

Examples of the substituent that can be introduced into the linking group represented by R ² include monovalent nonmetallic atomic groups other than hydrogen, such as halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups. Group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N- Diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy , Arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-aryl Ureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N-arylureido group, N′-alkyl-N-alkylureido group, N ′ -Alkyl-N-arylureido group, N ', N'-dialkyl-N-alkylureido group, N', N'-dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N ' -Aryl-N-arylureido group, N ', N'-diaryl-N-alkylureido group, N', N'-diaryl-N-arylureido group, N'-al Kill-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl-N-alkoxycarbonylamino group N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl group and its conjugate base group, Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, Alkylsulfinyl group An arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfo group (-SO ₃ H) and its conjugated base group, alkoxy sulfonyl group, aryloxy sulfonyl group, sulfinamoyl group, N- alkylsulfinamoyl group, N, N- Dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N -Dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, N-acylsulfamoyl group and its conjugate base group, N- alkylsulfonylsulfamoyl group (-SO ₂ NHSO ₂ alkyl)) and its conjugated base group, N- aryl sulfonylsulfamoyl group _{(-SO 2 NHSO 2 (aryl)} ) and its conjugated base group, N- alkylsulfonylcarbamoyl group (-CONHSO ₂ (alkyl)) and its conjugate Base group, N-arylsulfonylcarbamoyl group (—CONHSO ₂ (aryl)) and its conjugate base group, alkoxysilyl group (—Si (Oalkyl) ₃ ), aryloxysilyl group (—Si (Oaryl) ₃ ), hydroxysilyl Group (—Si (OH) ₃ ) and its conjugate base group, phosphono group (—PO ₃ H ₂ ) and its conjugate base group, dialkylphosphono group (—PO ₃ (alkyl) ₂ ), diarylphosphono group (— PO ₃ (aryl) _2), alkyl aryl phosphono group _{(-PO 3 (alkyl) (aryl} )) , Monoalkylphosphono group (—PO ₃ H (alkyl)) and its conjugate base group, monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group, phosphonooxy group (—OPO ₃ H ₂ ) and its Conjugated base group, dialkylphosphonooxy group (—OPO ₃ (alkyl) ₂ ), diarylphosphonooxy group (—OPO ₃ (aryl) ₂ ), alkylarylphosphonooxy group (—OPO ₃ (alkyl) (aryl)) ), Monoalkylphosphonooxy group (—OPO ₃ H (alkyl)) and its conjugate base group, monoarylphosphonooxy group (—OPO ₃ H (aryl)) and its conjugate base group, cyano group, nitro group, dialkyl boryl group (-B (alkyl) _2), Jiariruboriru group (-B (aryl) _2), alkyl aryl boryl -B (alkyl) (aryl)) , dihydroxy boryl group (-B (OH) ₂₎ and its conjugated base group, an alkyl hydroxy boryl group (-B (alkyl) (OH) ) and its conjugated base group, an aryl hydroxy boryl And the group (—B (aryl) (OH)) and its conjugate base group, aryl group, alkenyl group and alkynyl group.

  In the lithographic printing plate precursor according to the invention, although depending on the design of the photosensitive layer, a substituent having a hydrogen atom capable of hydrogen bonding, particularly a substituent having an acid dissociation constant (pKa) smaller than that of a carboxylic acid is , Because it tends to lower the printing durability. On the other hand, hydrophobic substituents such as halogen atoms, hydrocarbon groups (alkyl groups, aryl groups, alkenyl groups, alkynyl groups), alkoxy groups, aryloxy groups and the like are more preferable because they tend to improve printing durability. When the cyclic structure is a monocyclic aliphatic hydrocarbon having 6 or less members such as cyclopentane or cyclohexane, it preferably has such a hydrophobic substituent. If possible, these substituents may be bonded to each other or with a substituted hydrocarbon group to form a ring, and the substituent may be further substituted.

R ³ in the case where A in formula (i) is NR ³ — represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ³ include an alkyl group, an aryl group, an alkenyl group, and an alkynyl group.
Specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, isopropyl group, isobutyl group, sec-butyl group, 1 carbon number such as tert-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-norbornyl group Up to 10 linear, branched or cyclic alkyl groups.
Specific examples of the aryl group include carbon having one heteroatom selected from the group consisting of an aryl group having 1 to 10 carbon atoms such as a phenyl group, a naphthyl group, and an indenyl group, a nitrogen atom, an oxygen atom, and a sulfur atom. Examples include heteroaryl groups of 1 to 10, such as furyl, thienyl, pyrrolyl, pyridyl, and quinolyl groups.
Specific examples of the alkenyl group include those having 1 to 10 carbon atoms such as vinyl group, 1-propenyl group, 1-butenyl group, 1-methyl-1-propenyl group, 1-cyclopentenyl group, 1-cyclohexenyl group and the like. A linear, branched, or cyclic alkenyl group is mentioned.
Specific examples of the alkynyl group include alkynyl groups having 1 to 10 carbon atoms such as ethynyl group, 1-propynyl group, 1-butynyl group, and 1-octynyl group. The substituent that R ³ may have is the same as those exemplified as the substituent that R ² can introduce. However, the carbon number of R < ³ > is 1-10 including the carbon number of a substituent.

A in the general formula (i) is preferably an oxygen atom or —NH— because synthesis is easy.
N in the general formula (i) represents an integer of 1 to 5, and is preferably 1 in terms of printing durability.
Although the preferable specific example of the repeating unit represented by general formula (i) below is shown, this invention is not limited to these.

  One type of repeating unit represented by the general formula (i) may be contained in the binder polymer, or two or more types may be contained. The binder polymer in the present invention may be a polymer consisting of only the repeating unit represented by the general formula (i), but is usually used as a copolymer in combination with other copolymerization components. The total content of the repeating units represented by the general formula (i) in the copolymer is appropriately determined depending on the structure, the design of the photosensitive layer composition, etc. It is contained in a range of mol%, more preferably 5 to 40 mol%, still more preferably 5 to 20 mol%.

  As a copolymerization component in the case of using as a copolymer, a conventionally well-known thing can be used without a restriction | limiting, if it is a monomer which can be radically polymerized. Specific examples include monomers described in “Polymer Data Handbook—Basic Edition” (Edition of Polymer Society, Bafukan, 1986). One type of such copolymerization component may be used, or two or more types may be used in combination.

  The molecular weight of the binder polymer in the present invention is appropriately determined from the viewpoint of image formability and printing durability. The molecular weight is preferably in the range of 2,000 to 1,000,000, more preferably 5,000 to 500,000, and still more preferably 10,000 to 200,000.

  The mass average molecular weight of such a binder polymer is preferably from 2,000 to 1,000,000, more preferably from 10,000 to 300, from the viewpoints of film properties (press life) and solubility in a coating solvent. In the range of 20,000 to 200,000.

Further, the glass transition point (Tg) of such a binder polymer is preferably 70 to 300 ° C., more preferably 80 to 250 ° C., and most preferably 90 to 90 ° C. from the viewpoints of storage stability, printing durability, and sensitivity. It is in the range of 200 ° C.
As a means for increasing the glass transition point of the binder polymer, the molecule preferably contains an amide group or an imide group, and particularly preferably contains a methacrylamide methacrylamide derivative.

The binder polymer used in the present invention may be used alone or in combination of two or more.
Furthermore, in addition to the preferable binder polymer, a conventionally known polymer such as an acrylic polymer, a urethane polymer, or a styrene polymer may be used in combination. Even in such a case, the total content of ethylenically unsaturated double bonds per 1 g of the total weight of the binder polymer is preferably the same as that described above. That is, it is preferably 0.1 to 10.0 mmol, more preferably 1.0 to 7.0 mmol, and most preferably 2.0 to 5.5 mmol.
Moreover, it is preferable that the total acid value per 1g of such binder polymer total weight is the range of 0.45-3.6 mmol.

[Polymerization inhibitor]
In the polymerizable composition of the present invention, a compound having a polymerizable ethylenically unsaturated double bond, that is, a small amount of a thermal polymerization inhibitor may be added to prevent unnecessary thermal polymerization of the polymerizable compound. desirable. Suitable thermal polymerization inhibitors 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-nitrosophenylhydroxyamine primary cerium salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the mass of the nonvolatile components in the entire composition. If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide or the like may be added to prevent polymerization inhibition by oxygen and may be unevenly distributed on the surface of the layer in the course of drying after coating. The addition amount of the higher fatty acid derivative is preferably about 0.5% by mass to about 10% by mass with respect to the nonvolatile components in the entire composition.

[Colorant]
Furthermore, you may add dye or a pigment to the polymeric composition of this invention for the purpose of the coloring. As a result, when the polymerizable composition of the present invention is applied to the recording layer of a lithographic printing plate precursor, it is possible to improve the so-called plate inspection properties such as visibility after plate making as a printing plate and suitability for image density measurement. it can. As the colorant, many dyes cause a decrease in the sensitivity of the photopolymerization type photosensitive layer. Therefore, it is particularly preferable to use a pigment as the colorant. Specific examples include pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes. The addition amount of the dye and the pigment as the colorant is preferably about 0.5% by mass to about 5% by mass with respect to the non-volatile components in the entire composition.

[Other additives]
The polymerizable composition of the present invention further improves the ink inking property on the surface when used as a recording layer for inorganic fillers, other plasticizers, and image recording materials for improving the physical properties of the cured film. A known additive such as a sensitizing agent that can be added may be added according to the purpose.
Examples of plasticizers include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerin, and addition polymerization with binder polymer. Generally, it can be added in a range of 10% by mass or less based on the total mass with the compound. In addition, in the lithographic printing plate precursor described later, in order to enhance the effect of heating and exposure after development for the purpose of improving the film strength (printing durability) described later, a UV initiator, a thermal crosslinking agent, etc. are added. Can also be done.

  The polymerizable composition of the present invention can be suitably used as a recording layer of a lithographic printing plate precursor because it is cured with high sensitivity by heating or exposure and has excellent film properties of a cured film. Hereinafter, the lithographic printing plate precursor which is a preferred use mode of the polymerizable composition of the present invention will be described.

<Lithographic printing plate precursor>
When the polymerizable composition of the present invention is applied to a lithographic printing plate precursor, the polymerizable composition of the present invention can be contained in a recording layer of a lithographic printing plate precursor comprising a recording layer on a support. That's fine. Further, the lithographic printing plate precursor may have an undercoat layer, a protective layer and the like depending on the purpose in addition to the recording layer, and in particular, an aspect in which the recording layer and the protective layer are sequentially laminated on the support. Is more preferable. Such a lithographic printing plate precursor is coated on a suitable support or intermediate layer by dissolving a photosensitive layer coating solution containing the photosensitive composition of the present invention or a coating layer component of a desired layer such as a protective layer in a solvent. Can be manufactured.

  The recording layer formed of the polymerizable composition of the present invention comprising an infrared absorber, the above-mentioned specific radical initiator, an ethylenically unsaturated compound (also referred to as an addition polymerizable compound), and a binder polymer as essential components. A heat-polymerizable negative recording layer. In such a heat-polymerizable negative recording layer, the radical initiator is decomposed by the application of energy such as heat and light to generate radicals, and the generated radical causes a polymerization reaction by the generated radicals, thereby applying energy. It has a mechanism that only the region is cured. Since the polymerizable composition of the present invention contains an infrared absorber, the infrared absorber absorbs it and generates heat when exposed to infrared laser. Since the radical initiator can be efficiently decomposed by the heat, the lithographic printing plate precursor having such a recording layer is particularly suitable for plate making directly drawn with an infrared laser beam having a wavelength of 760 to 1,200 nm. It is suitable and exhibits higher printing durability and image forming properties than conventional lithographic printing plate precursors.

When the recording layer is applied, the polymerizable composition of the present invention may be dissolved in a suitable organic solvent and applied onto the support or the intermediate layer.
Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, lactic acid There is ethyl. These solvents can be used alone or in combination. 2-50 mass% is suitable for the density | concentration of solid content in a coating solution.

The coating amount of the recording layer mainly affects sensitivity, developability, exposure film strength and printing durability, and is preferably selected as appropriate according to the application. When the coating amount is too small, the printing durability is not sufficient. On the other hand, if the amount is too large, the sensitivity is lowered, it takes time for exposure, and a longer time is required for development processing, which is not preferable. As the coating amount when forming the recording layer of the lithographic printing plate precursor for scanning exposure which is the main object of the present invention, a range of about 0.1 to about 10 g / m ^{2 by} weight after drying is appropriate. More preferably, it is the range of 0.5-5 g / m < ² >.

[Support]
As a support for a lithographic printing plate precursor to which the polymerizable composition of the present invention can be applied, a conventionally known hydrophilic support for use in a lithographic printing plate precursor can be used without limitation.
The support used is preferably a dimensionally stable plate, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc). , Copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), Paper or plastic film, etc. on which such metals are laminated or vapor-deposited are included. Appropriately known physical and chemical treatments are applied to these surfaces for the purpose of imparting hydrophilicity and improving strength as necessary. You may give it.

  In particular, preferred supports include paper, polyester film or aluminum plate, among which dimensional stability is good, relatively inexpensive, and a surface with excellent hydrophilicity and strength is provided by surface treatment as required. An aluminum plate that can be formed is more preferable. A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

An aluminum plate is a metal plate mainly composed of dimensionally stable aluminum. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or aluminum (alloy) is laminated. Or it is chosen from the vapor-deposited plastic film or paper. In the following description, the above-mentioned support made of aluminum or an aluminum alloy is generically used as an aluminum support. Examples of the foreign element contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is 10% by mass or less. In the present invention, a pure aluminum plate is suitable. However, since pure aluminum is difficult to manufacture in terms of refining technology, it may contain slightly different elements. Thus, the composition of the aluminum plate applied to the present invention is not specified, but conventionally known and used materials such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. It can be used as appropriate.
Moreover, the thickness of the aluminum support body used for this invention is about 0.1 mm-about 0.6 mm. This thickness can be appropriately changed depending on the size of the printing press, the size of the printing plate, and the user's desire. The aluminum support may be subjected to a support surface treatment described later as necessary. Of course, it may not be applied.

(Roughening treatment)
Examples of the roughening treatment method include mechanical roughening, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Furthermore, the electrochemical surface roughening method in which the surface is electrochemically roughened in hydrochloric acid or nitric acid electrolyte solution, the aluminum surface is scratched with a metal wire, the wire brush grain method, the surface of the aluminum is polished with a polishing ball and an abrasive. A mechanical graining method such as a pole grain method, a brush grain method in which the surface is roughened with a nylon brush and an abrasive, can be used, and the above roughening methods can be used alone or in combination.

How usefully employed to surface roughening Among these are electrochemical method of chemically roughening in a hydrochloric acid or nitric acid electrolytic solution, a suitable anode time electricity is in the range of 50~400C / dm ² . More specifically, in an electrolytic solution containing 0.1 to 50% hydrochloric acid or nitric acid, AC and / or under conditions of a temperature of 20 to 80 ° C., a time of 1 second to 30 minutes, and a current density of 10 to 50 A / dm ^2. It is preferable to perform direct current electrolysis.

  The roughened aluminum support may be chemically etched with acid or alkali. Etching agents suitably used are caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like, and preferred ranges of concentration and temperature are 1 to 50% by mass, 20 to 100 ° C. Pickling is performed to remove dirt (smut) remaining on the surface after etching. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid and the like are used. In particular, as a method for removing the smut after the electrochemical surface roughening treatment, 15 to 65 mass% sulfuric acid is preferably used in a temperature range of 50 to 90 ° C. as described in JP-A-53-12739. And an alkali etching method described in Japanese Patent Publication No. 48-28123. After the treatment as described above, the method conditions are not particularly limited as long as the center line average roughness Ra of the treatment surface is 0.2 to 0.7 μm.

(Anodizing treatment)
The aluminum support that has been treated as described above to form an oxide layer is then anodized.
In the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, or an aqueous solution of boric acid / sodium borate is used alone or in combination as a main component of the electrolytic bath. In this case, the electrolyte solution may of course contain at least components normally contained in at least an Al alloy plate, an electrode, tap water, groundwater and the like. Further, the second and third components may be added. Here, the second and third components are, for example, metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and ammonium ions. Examples include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions and the like, and the concentration is 0 to 10,000 ppm. May be included. The conditions of the anodizing treatment are such that the amount of the anodized film produced by the treatment is 0.5 to 10.0 g / m ² , more preferably 1.0 to 5.0 g / m ² . The concentration of the acid as the main component is preferably 30 to 500 g / liter, the treatment liquid temperature is 10 to 70 ° C., and the treatment is performed by direct current or alternating current electrolysis in the range of a current density of 1 to 40 A / m ² .

A widely known method can be applied as the hydrophilic treatment on the surface of the support. As a particularly preferable treatment, a hydrophilic treatment with silicate or polyvinylphosphonic acid is performed. A film | membrane is formed by 2-40 mg / m < ² > as Si or P element amount, More preferably, it is 4-30 mg / m < ² >. The coating amount can be measured by fluorescent X-ray analysis.

  The hydrophilization treatment is carried out by applying an anodized film to an aqueous solution containing 1 to 30% by mass, preferably 2 to 15% by mass of alkali metal silicate or polyvinylphosphonic acid, and having a pH of 10 to 13 at 25 ° C. This is carried out by immersing the aluminum support on which is formed, for example, at 15 to 80 ° C. for 0.5 to 120 seconds.

  As the alkali metal silicate used for the hydrophilization treatment, sodium silicate, potassium silicate, lithium silicate, or the like is used. Examples of the hydroxide used for increasing the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend alkaline-earth metal salt or Group IVB metal salt with said process liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble substances such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Salt. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, etc. Can be mentioned.

  Alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. A preferable range of these metal salts is 0.01 to 10% by mass, and a more preferable range is 0.05 to 5.0% by mass. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. Surface obtained by combining a support with electrolytic grains as disclosed in JP-B-46-27481, JP-A-52-58602, JP-A-52-30503, and the above anodizing treatment and hydrophilization treatment Processing is also useful.

[Intermediate layer (undercoat layer)]
The lithographic printing plate precursor according to the invention may be provided with an intermediate layer (undercoat layer) for the purpose of improving the adhesion between the recording layer and the support and the stain resistance. Specific examples of such an intermediate layer include JP-B-50-7481, JP-A-54-72104, JP-A-59-101651, JP-A-60-149491, JP-A-60-232998, JP-A-3-56177, JP-A-4-282737, JP-A-5-16558, JP-A-5-246171, JP-A-7-159983, JP-A-7-314937, JP-A-8-202025, Special Kaihei 8-320551, JP 9-34104, JP 9-236911, JP 9-269593, JP 10-69092, JP 10-115931, JP 10-161317, JP 10-260536, JP-A-10-282682, JP-A-11-84684, Japanese Patent Application No. 8-225335, Japanese Patent Application No. 8-270098, Japanese Patent Application No. 9-195863, Japanese Patent Application No. 9-195864, Japanese Patent Application No. 9-89646, Japanese Patent Application No. 9-106068, Japanese Patent Application No. 9-183834, Japanese Patent Application No. 9-264411, Japanese Patent Application No. 9 -127232, Japanese Patent Application No. 9-245419, Japanese Patent Application No. 10-127602, Japanese Patent Application No. 10-170202, Japanese Patent Application No. 11-36377, Japanese Patent Application No. 11-165661, Japanese Patent Application No. 11-284091 No., Japanese Patent Application No. 2000-14697, and the like.

[Protective layer]
The recording layer of the lithographic printing plate precursor according to the present invention is a heat-polymerizable negative recording layer. In order to perform exposure in the air, a protective layer (also referred to as an overcoat layer) is further provided on the recording layer. It is preferable to provide it. The protective layer is basically provided to protect the recording layer, but when the recording layer has a radically polymerizable image forming mechanism as in the present invention, it has a role as an oxygen blocking layer and has a high illuminance. When exposed with an infrared laser, it functions as an ablation preventing layer.
In addition to the properties desired for the protective layer, in addition to the above, the transmission of light used for exposure is not substantially inhibited, the adhesiveness with the photosensitive layer is excellent, and it can be easily removed in the development process after exposure. Things are desirable. Such a protective layer has been conventionally devised and described in detail in US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, polyacrylamide, etc. Or they can be mixed. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components.
Specific examples of polyvinyl alcohol include those that are hydrolyzed by 71 to 100% and have a polymerization repeating unit 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 and the like.

Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of unsubstituted vinyl alcohol units in the oxygen barrier layer), the higher the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. . However, when the oxygen barrier property is extremely increased, there arises a problem that unnecessary polymerization reaction occurs during production and raw storage, and unnecessary fogging and image line thickening occur during image exposure.
Accordingly, the oxygen permeability A at 25 ° C. and 1 atm is preferably 0.2 ≦ A ≦ 20 (ml / m ² · day).
The molecular weight of the (co) polymer such as polyvinyl alcohol (PVA) can be in the range of 2000 to 00000, preferably 20,000 to 00000.
The protective layer is preferably composed of polyvinyl alcohol (PVA) as a main component and mixed with polyvinylpyrrolidone (PVP), and the content of PVA is preferably 60 to 99.9% by mass, more preferably 65 to 90% by mass. 70 to 85% by mass is most preferable. Moreover, as content of PVP, 0.1-40 mass% is preferable, 10-35 mass% is more preferable, 15-30 mass% is the most preferable.

As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer Mass% can be added.
The thickness of the protective layer after drying is preferably from 0.5 to 5 μm, particularly preferably from 0.5 to 2 μm.

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

In order to make a lithographic printing plate from the lithographic printing plate precursor according to the present invention, at least exposure and development processes are performed.
As a light source for exposing the lithographic printing plate precursor according to the present invention, an infrared laser is preferable, and thermal recording using an ultraviolet lamp or a thermal head is also possible.
In particular, in the present invention, image exposure is preferably performed with a solid-state laser and a semiconductor laser that emit infrared rays having a wavelength of 750 nm to 1400 nm. The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec. The energy applied to the planographic printing plate precursor is preferably 10 to 300 mJ / cm ² . If the exposure energy is too low, the image recording layer does not sufficiently cure. If the exposure energy is too high, the image recording layer may be laser ablated and the image may be damaged.

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

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

In the present invention, the development treatment may be performed immediately after exposure, but the heat treatment may be performed between the exposure step and the development step. The heat treatment condition is preferably 5 seconds to 5 minutes in the temperature range of 60 to 150 ° C.
The heat treatment can be appropriately selected from conventionally known various methods. Specific examples include a method of heating the lithographic printing plate precursor while being in contact with a panel heater or a ceramic heater, a non-contact heating method using a lamp or hot air, and the like. By performing the heat treatment, it is possible to reduce the amount of laser energy required for image recording of the laser to be irradiated.

  Moreover, when the lithographic printing plate precursor to which the present invention is applied is an embodiment having a protective layer, pre-water washing for removing the protective layer may be performed before the development step. The pre-water washing is performed, for example, by a method in which water is discharged from the spray pipe onto the surface of the protective layer of the planographic printing plate precursor, and the protective layer is wetted and then removed by a brush roller. For the pre-water washing, for example, tap water is used. Further, when the developing process is performed by an automatic developing machine, a pre-water washing process may be performed in the automatic developing machine.

The lithographic printing plate precursor according to the invention is subjected to development processing after being exposed or after being subjected to a heating step or a pre-water washing step. As the developer used in such development processing, an alkaline aqueous solution having a pH of 14 or less is particularly preferred, and an alkaline aqueous solution having a pH of 8 to 12 containing an anionic surfactant is more preferably used.
Examples of the alkaline agent used to prepare the developer include tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, carbonic acid. Examples include inorganic alkali agents such as sodium hydrogen, potassium, ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used. These alkali agents are used alone or in combination of two or more.

Further, in the development processing of the lithographic printing plate precursor according to the present invention, it is possible to use a developer obtained by adding 1 to 20% by mass of an anionic surfactant in the developer, such as developability and abrasion resistance of the image area. Although it is preferable from the viewpoint of balance with strength, it is more preferable to use one containing 3 to 10% by mass of an anionic surfactant.
Anionic surfactants include, for example, sodium salt of lauryl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, such as sodium salt of isopropyl naphthalene sulfonic acid, sodium salt of isobutyl naphthalene sulfonic acid, polyoxy Higher carbon number such as sodium salt of ethylene glycol mononaphthyl ether sulfate ester, sodium salt of dodecylbenzene sulfonic acid, alkylaryl sulfonate such as sodium salt of metanitrobenzene sulfonic acid, secondary sodium alkyl sulfate, etc. Aliphatic alcohol phosphates such as alcohol sulfates, sodium salts of cetyl alcohol phosphates, eg C _{17 H 33 CON (CH 3)} CH 2 CH 2 SO 3 sulfonates of alkylamides such as Na, for example, sodium sulfosuccinate dioctyl ester, sulfonate of dibasic aliphatic esters such as sodium sulfosuccinate dihexyl ester Salts are included.

  Moreover, you may add the organic solvent which mixes with water, such as benzyl alcohol, to a developing solution as needed. As the organic solvent, those having a solubility in water of about 10% by mass or less are suitable, and preferably selected from those having 5% by mass or less. For example, 1-phenylethanol, 2-phenylethanol, 3-phenylpropanol, 1,4-phenylbutanol, 2,2-phenylbutanol, 1,2-phenoxyethanol, 2-benzyloxyethanol, o-methoxybenzyl alcohol, m -Methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 4-methylcyclohexanol, 3-methylcyclohexanol and the like can be mentioned. The content of the organic solvent is preferably 1 to 5% by mass with respect to the total mass of the developer at the time of use. The amount used is closely related to the amount of surfactant used, and it is preferable to increase the amount of anionic surfactant as the amount of organic solvent increases. This is because when the amount of the organic solvent is large and the amount of the anionic surfactant is small, the organic solvent is not dissolved, so that it is impossible to expect good developability.

Furthermore, additives such as an antifoaming agent and a hard water softening agent can be further contained as necessary. Examples of the water softener include Na ₂ P ₂ O ₇ , Na ₅ P ₃ O ₃ , Na ₃ P ₃ O ₉ , Na ₂ O ₄ P (NaO ₃ P) PO ₃ Na ₂ , calgon (polymetaphosphoric acid). Polyphosphates such as sodium), aminopolycarboxylic acids (eg, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its Hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its potassium salt, its sodium salt; 1,2-diaminocyclohexanetetraacetic acid, its potassium salt, its sodium salt; 1,3-diamino 2-propanoltetraacetic acid, its potash Salts thereof, sodium salts thereof), other polycarboxylic acids (for example, 2-phosphonobutanetricarboxylic acid-1,2,4, potassium salts thereof, sodium salts thereof; 2 monophosphonobutanone tricarboxylic acids-2,3, 4, its potassium salt, its sodium salt, etc.), organic phosphonic acids (for example, 1-phosphonoethanetricarboxylic acid-1,2,2, its potassium salt, its sodium salt; 1-hydroxyethane-1,1-diphosphone) Acid, its potassium salt, its sodium salt; aminotri (methylenephosphonic acid), its potassium salt, its sodium salt, etc.). The optimum amount of such a hard water softener varies depending on the hardness of the hard water used and the amount used, but is generally 0.01 to 5% by weight, more preferably in the developer at the time of use. It can contain in 0.01-0.5 mass%.

  Furthermore, when developing a lithographic printing plate precursor using an automatic processor, the developer becomes fatigued according to the amount of processing, so that the processing capacity can be restored using a replenisher or fresh developer. Also good. In this case, it is preferable to replenish by the method described in US Pat. No. 4,882,246. Developers described in JP-A-50-26601, 58-54341, JP-B-56-39464, 56-42860, and 57-7427 are also preferable.

  The lithographic printing plate precursor thus developed is subjected to washing water, surface activity as described in JP-A Nos. 54-8002, 55-11545, 59-58431, and the like. It may be post-treated with a rinsing liquid containing an agent, a desensitizing liquid containing gum arabic, starch derivatives, and the like. These treatments can be used in various combinations for the post-treatment of the lithographic printing plate precursor according to the invention.

In plate making of a lithographic printing plate precursor using the polymerizable composition of the present invention, for the purpose of improving image strength and printing durability, the image after development may be subjected to full post-heating or full exposure. It is valid.
Very strong conditions can be used for heating after development. Usually, the heating temperature is 200 to 500 ° C. If the heating temperature after development is low, sufficient image strengthening action cannot be obtained, and if it is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.

The planographic printing plate obtained by the above processing is loaded on an offset printing machine and used for printing a large number of sheets.
As plate cleaners used for removing stains on the plate during printing, conventionally known plate cleaners for PS plates are used. For example, CL-1, CL-2, CP, CN-4, CN, CG-1, PC-1, SR, IC (made by Fuji Photo Film Co., Ltd.), etc. are mentioned.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.
[Example 1]
[Create support]
The surface treatment shown below was performed using a JIS A 1050 aluminum plate having a thickness of 0.30 mm and a width of 1030 mm.

<Surface treatment>
In the surface treatment, the following various treatments (a) to (f) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) The aluminum plate was etched at a caustic soda concentration of 26 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. to dissolve the aluminum plate at 5 g / m ² . Thereafter, it was washed with water.
(B) A desmut treatment by spraying was performed with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (including 0.5% by mass of aluminum ions), and then washed with water.

(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (including 0.5% by mass aluminum ions and 0.007% by mass ammonium ions) at a temperature of 30 ° C. The AC power source was subjected to an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 2 msec until the current value reached a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 250 C / cm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Thereafter, it was washed with water.

(D) The aluminum plate was spray-etched at 35 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass to dissolve the aluminum plate by 0.2 g / m ² , The removal of the smut component mainly composed of aluminum hydroxide generated during chemical roughening and the edge portion of the generated pit were dissolved to smooth the edge portion. Thereafter, it was washed with water.
(E) A desmut treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), and then washing with water by spraying.

(F) Anodization was performed for 50 seconds at a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), a temperature of 33 ° C., and a current density of 5 (A / dm ² ). Thereafter, it was washed with water. At this time, the weight of the anodized film was 2.7 g / m ² .

[Photosensitive layer]
Next, the following photosensitive layer coating solution [P-1] was prepared and applied to the above aluminum support using a wire bar. Drying was carried out at 122 ° C. for 27 seconds with a hot air drying apparatus to obtain a lithographic printing plate precursor. The coating amount after drying was 1.3 g / m ² .

<Photosensitive layer coating solution [P-1]>
・ Infrared absorber (IR-1) 0.074g
-Polymerization initiator (OS-1) 0.311g
・ Additive (PM-1) 0.151g
・ Polymerizable compound (AM-1) 1.00 g
-Binder polymer (BT-1) 1.00g
・ Ethyl violet (C-1) 0.04g
・ Fluorine-based surfactant 0.015g
(Megafuck F-780-F Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 10.4g
・ Methanol 4.83g
・ 10.4 g of 1-methoxy-2-propanol

In addition, a polymerization initiator (OS-1) points out what is mentioned as a compound example of the radical initiator represented by the above-mentioned general formula (1).
Infrared absorber (IR-1), additive (PM-1), polymerizable compound (AM-1), binder polymer (BT-1), and ethyl violet (C-1) used in the photosensitive layer coating solution The structure of is shown below.
In addition, content of the ethylenically unsaturated double bond of the following binder polymer (BT-1) is 2.75 mmol / g, and an acid value is 0.80 mmol / g.

[Protective layer (overcoat layer)]
A mixed aqueous solution of polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) and polyvinyl pyrrolidone (BASF Corp., Rubiscol K-30) was applied to the photosensitive layer surface with a wire bar, The sample was dried at 125 ° C. for 75 seconds using a type dryer. The content of polyvinyl alcohol / polyvinylpyrrolidone was 4/1% by mass, and the coating amount (coating amount after drying) was 2.30 g / m ² .

(Examples 2 to 5)
In place of the radical initiator (OS-1) in the photosensitive layer coating solution [P-1] used in Example 1, a photosensitive layer coating solution [P- The photosensitive lithographic printing plate precursors of Examples 2 to 5 were obtained in the same manner as in Example 1 except that 2] to [P-5] were used for forming the photosensitive layer.

(Comparative Example 1)
Instead of the radical initiator (OS-1) in the photosensitive layer coating solution [P-1] used in Example 1, a photosensitive layer coating solution [P- 6] was used in the same manner as in Example 1 except that the photosensitive lithographic printing plate precursor of Comparative Example 1 was obtained except that 6] was used for forming the photosensitive layer.

(Comparative Example 2)
Instead of the radical initiator (OS-1) in the photosensitive layer coating solution [P-1] used in Example 1, a photosensitive layer coating solution [P- 6] was used in the same manner as in Example 1 except that the photosensitive lithographic printing plate precursor of Comparative Example 1 was obtained except that 6] was used for forming the photosensitive layer.

[Evaluation]
(1) Sensitivity evaluation The obtained lithographic printing plate precursors of Examples 1 to 5 and Comparative Examples 1 and 2 were subjected to Creo Trendsetter 3244VX equipped with a water-cooled 40W infrared semiconductor laser, with a resolution of 175 lpi and an outer drum rotation speed of 150 rpm. The exposure was performed while changing the log E by 0.15 in the range of 0 to 8 W output. The exposure was performed under conditions of 25 ° C. and 50% RH. After the exposure, the protective layer was removed by washing with tap water, and then developed using LP-1310HII manufactured by Fuji Photo Film Co., Ltd. at 30 ° C. for 12 seconds. The developer used was a 1: 4 water-diluted water of DV-2 manufactured by FUJIFILM Corporation, and the 1: 1 water-diluted solution of GN-2K manufactured by FUJIFILM Corporation was used as the finisher.
The density of the image portion of the lithographic printing plate obtained by the development was measured using a Macbeth reflection densitometer RD-918, and the cyan density was measured using a red filter equipped in the densitometer. The reciprocal of the exposure necessary to obtain a measured density of 0.8 was used as an index of sensitivity. In the evaluation results, the sensitivity of the lithographic printing plate obtained in Example 1 was set to 100, and the sensitivity of other lithographic printing plates was set as a relative evaluation. The larger the value, the better the sensitivity. The results are shown in Table 1.

(2) Raw storage stability evaluation (time stability evaluation)
The unexposed lithographic printing plate precursor was stored at 45 ° C. and 75% RH for 3 days, then exposed and developed by the following method, and the non-image area density was measured using a Macbeth reflection densitometer RD-918. . The lithographic printing plate precursor immediately after production was also exposed and developed in the same manner, and the non-image area density was measured. In this evaluation, the difference Δ between the non-image area densities was obtained and used as an index of raw preservation. The smaller the value of Δ, the better the raw preservation, and 0.02 or less is a level that causes no practical problem. The results are shown in Table 1.

(3) Evaluation of printing durability An 80% flat screen image with a resolution of 175 lpi was output to the produced lithographic printing plate precursor with a water-cooled 40W infrared semiconductor laser and a resolution of 175 lpi, 8 W output, outer drum rotation speed 206 rpm And exposure with a plate surface energy of 100 mJ / cm ² . After the exposure, the protective layer was removed by rinsing with tap water, and then developed by the same method as in (1) Sensitivity evaluation development step. Each time 10,000 sheets of the obtained lithographic printing plate are printed using a printing machine Lithron manufactured by Komori Corporation, the ink is wiped off from the surface of the printing plate by a multi-cleaner manufactured by Fuji Photo Film Co., Ltd. Printing was performed while repeating the work. The number of printed sheets was used as an index of printing durability. The results are shown in Table 1.

As is apparent from Table 1, the lithographic printing plate precursors of Examples 1 to 5 can be recorded with high sensitivity, have excellent temporal stability, and have good printing durability.
On the other hand, Comparative Example 1 using Comparative Compound-1 (a known onium salt) as a radical initiator is excellent in raw storability, but is inferior in both sensitivity and printing durability compared to the lithographic printing plate precursors in Examples. It was found that Comparative Example 2 using Comparative Compound-2 (a known trihaloalkyl compound) as a radical initiator had good sensitivity and printing durability but was inferior in raw storability.

Claims (3)

(A) a radical initiator represented by the following general formula (1), (B) an ethylenically unsaturated compound,
And (C) an infrared absorber, a polymerizable composition.

In the general formula (1), X represents a carbonyl group, a sulfone group, or a sulfoxide group, and Y represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a benzoyl group, or a heterocyclic group.
Q and Z each independently represent a monovalent substituent consisting of a nonmetallic atom, and these are one or more selected from the group consisting of a hydrogen atom, an oxygen atom, a halogen atom, a nitrogen atom, and a sulfur atom You may have a substituent containing an atom.   (D) The polymeric composition of Claim 1 containing the binder polymer which has an ethylenically unsaturated double bond in a molecule | numerator.   The polymerizable composition according to claim 1 or 2, wherein the infrared absorber (C) is a cyanine dye.