JP2007086341A - Photosensitive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive composition having high sensitivity to oscillation wavelengths of an inexpensive short wavelength semiconductor laser, excellent in developing property, and storage stability, and useful as a photosensitive layer of a planographic printing plate precursor for scanning exposure. <P>SOLUTION: The photosensitive composition contains (A) a sensitizing dye having a solubility of 100 (mg/l) or more with an alkali developing solution at 25°C (pH=11.95), (B) an initiator compound that can produce a radical, acid or base, and (C) a polymerizable compound that reacts with at least one of radicals, acids and bases. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a photosensitivity that can be used for image forming materials such as three-dimensional stereolithography, holography, planographic printing plates, color proofs, photoresists, and color filters, and photocurable resin materials such as inks, paints, and adhesives. Relates to the composition. More particularly, the present invention relates to a photosensitive composition that can be directly made from a digital signal of a computer or the like using various lasers, and is suitably used as a so-called lithographic printing plate material capable of direct plate making.

Conventionally, as a lithographic printing plate, a PS plate having a configuration in which a lipophilic photosensitive resin layer is provided on a hydrophilic support has been widely used. As the plate making method, usually, mask exposure (surface After exposure), the desired printing plate was obtained by dissolving and removing the non-image area.
In recent years, digitization techniques for electronically processing, storing, and outputting image information using a computer have become widespread, and various new image output methods corresponding to the technology have come into practical use. As a result, computer-to-plate (CTP) technology that scans highly directional light such as laser light in accordance with digitized image information and directly manufactures a printing plate without using a lith film is desired. Obtaining a printing plate precursor adapted to this is an important technical issue.

  As one of methods for obtaining such a lithographic printing plate capable of scanning exposure, a method of forming an ink receptive resin layer region on a support having a hydrophilic surface is employed. This is a material in which a negative photosensitive layer that is cured by scanning exposure to form an ink receptive region is provided on a support, and has a configuration using a photopolymerization composition excellent in photosensitive speed. Some have been proposed and are already in practical use. The lithographic printing plate precursor having such a constitution has desirable printing plate and printing performance that are easy to develop, and further have excellent resolution, thickness, printing durability, and stain resistance.

The photopolymerizable composition basically contains a polymerizable compound having an ethylenically unsaturated bond, a photopolymerization initiation system, and optionally a binder resin, and by scanning exposure, the photoinitiation system absorbs light, An active species such as an active radical is generated to cause and advance the polymerization reaction of the polymerizable compound, thereby curing the exposed area to form an image.
In such a photopolymerizable composition capable of scanning exposure, various photoinitiating systems excellent in photosensitivity have been disclosed (for example, see Non-Patent Documents 1 and 2). The photoinitiating system described in these documents is a light source when applied to a conventional CTP system using a long wavelength visible light source such as an Ar laser (488 nm) or an FD-YAG laser (532 nm) as an exposure light source. In the present situation where the output is not sufficiently high, sufficient sensitivity cannot be obtained, and a highly sensitive starting system that can be adapted to further high-speed exposure is desired.

On the other hand, in recent years, for example, semiconductor lasers that use InGaN-based materials and can continuously oscillate in the 350 nm to 450 nm region have been put into practical use. The scanning exposure system using these short-wave light sources has an advantage that an economical system can be constructed while having a sufficient output because a semiconductor laser can be manufactured at a low cost because of its structure. Furthermore, as compared with a system using a conventional FD-YAG or Ar laser, a photosensitive material having photosensitivity in a short wavelength region capable of working under a brighter safe light can be used. However, there is currently no known photoinitiating system having sufficient sensitivity for scanning exposure in such a short wavelength region of 350 nm to 450 nm.
In response to this, the applicants of the present application have proposed a photosensitive composition containing a sensitizing dye that is highly sensitive in this short wavelength region (see, for example, Patent Document 1), but light containing these sensitizing dyes and the like. A further increase in sensitivity of the starting system is desired.

  Further, for example, as described in Non-Patent Documents 3 and 4, obtaining a highly sensitive photoinitiation system is a technique that is still widely desired in the imaging field. The photoinitiating system consisting of a sensitizing dye and an initiator compound can generate an acid and a base in addition to the above active radicals by selecting the initiator compound. For example, images such as stereolithography, holography, and color hard copy It is used in the field of manufacturing, manufacturing of electronic materials such as photoresists, and photocurable resin materials such as inks, paints, and adhesives. In these industrial fields, it is eagerly desired to find a sensitizing dye excellent in light absorption and sensitizing ability for the purpose of efficiently causing the decomposition of the initiator compound.

In addition, it is important for image forming materials containing these photosensitive compositions to have high sensitivity and excellent storage stability over time. In recent years, the components in the photosensitive layer are used in the development processing step. It has become important not to deposit (development residue free).
That is, in addition to achieving both high sensitivity and storage stability of the image forming material, a new problem of developing property has arisen, and a new technique that has not been heretofore has been demanded.
JP 2004-309777 A Bruce M.M. Monroe et al., Chemical Review, 93, 435 (1993). R. S. Davidson, Journal of Photochemistry and biology A: Chemistry, 73.81 (1993). Je. Pee. J. P. Faussier, “Photoinitiated Polymerization—Theory and Applications”, Rapra Review vol. 9, Report, Papra Technology (1998) M. By Tsunooka et al., Prog. Polym. Sci. , 21, 1 (1996)

  The object of the present invention in consideration of the above problems is high sensitivity to an oscillation wavelength of 350 nm to 450 nm of an inexpensive shortwave semiconductor laser, and is excellent in workability, printing durability, and developability, for example, suitable for a CTP system. An object of the present invention is to provide a photosensitive composition using a novel photoinitiating system useful as a photosensitive layer of a lithographic printing plate precursor for scanning exposure.

As a result of intensive studies to achieve the above-mentioned object, the present inventors have given a high photosensitivity to a novel photoinitiation system comprising a sensitizing dye having a specific structure and an initiator compound, particularly 350 nm to 450 nm. The present invention was completed by finding that high sensitivity was obtained in the vicinity and excellent developability was obtained.
That is, the present invention is as follows.

(1) (A) a sensitizing dye having a solubility in an alkaline developer at 25 ° C. (pH = 11.95) of 100 (mg / l) or more,
(B) an initiator compound capable of generating a radical, an acid or a base, and (C) a polymerizable compound which reacts with at least one of a radical, an acid or a base,
Containing the photosensitive composition.
(2) (A) a sensitizing dye represented by the following general formula (I) and having a solubility in an alkaline developer at 25 ° C. (pH = 11.95) of 100 (mg / l) or more;
(B) an initiator compound capable of generating a radical, an acid or a base, and (C) a polymerizable compound which reacts with at least one of a radical, an acid or a base,
Containing the photosensitive composition.

(In the general formula (I), A represents an aromatic ring or a hetero ring which may have a substituent, R ₁ represents a hydrogen atom or a monovalent nonmetallic atomic group. A and R ₁ are each They can be bonded to each other to form an aliphatic or aromatic ring, and Z represents a 5-membered or 6-membered ring structure containing a hetero atom.
The sensitizing dye represented by the general formula (I) has at least one COOR ₂ group, SO ₃ R ₃ group, PO at a site selected from a substituent on A, Z, R ₁ or R _{1. It} has a substituent selected from ₃ R ₄ group, OH group, and OCOR ₅ group. R ₂ , R ₃ , R ₄ , and R ₅ each independently represent a monovalent nonmetallic atomic group that is not a hydrogen atom. )

(3) An image recording material comprising a photosensitive layer containing the photosensitive composition according to any one of (1) and (2) above on a support.

Although the mechanism of action of the present invention is not clear, the sensitizing dye represented by the general formula (I) is highly sensitive to wavelengths from 350 nm to 450 nm, and is irradiated with an oscillation wavelength of an inexpensive shortwave semiconductor laser (exposure). ), The electron excited state due to the light absorption, and the electron transfer, energy transfer, heat generation, etc. associated with the electron excited state act on the coexisting initiator compound to cause a chemical change in the initiator compound, thereby generating radicals. To produce an acid or base. Furthermore, at least any one of radicals, acids and bases generated here causes irreversible changes such as color development, decoloration, and polymerization in the polymerizable compound that reacts. By using an addition polymerizable compound having an ethylenically unsaturated double bond, which is preferable among such compounds, the curing reaction starts and proceeds, and the exposed region is cured. For this reason, by using the photosensitive composition of the present invention, it has sufficient sensitivity for scanning exposure with a short-wave semiconductor laser, has excellent stability under yellow light, and can be handled under bright safe light. It has the advantage. Accordingly, in this photosensitive composition, a lithographic printing plate precursor using an addition polymerizable compound as a photosensitive layer is capable of recording with high sensitivity and exhibits printing performance excellent in safelight stability. Conceivable.
Further, it has been found that a photosensitive composition containing a sensitizing dye having a specific structure of the present invention is excellent in developability. The reason for this is that since it has a hydrophilic substituent (OH, OCOR, COOR, etc.) in the vicinity of the sensitizing dye structure, it has a high affinity for a developer whose main component is water, which causes dye precipitation and residue formation. This is thought to have an effect on the improvement of developability.

  According to the present invention, a lithographic plate for scanning exposure that is highly sensitive to an oscillation wavelength of 350 nm to 450 nm of an inexpensive shortwave semiconductor laser and excellent in workability, printing durability, and developability, for example, compatible with a CTP system. A photosensitive composition useful as a photosensitive layer of a printing plate precursor is provided.

Hereinafter, the present invention will be described in detail.
The photosensitive composition of the present invention comprises:
(A) A sensitizing dye having a solubility in an alkali developer at 25 ° C. (pH = 11.95) of 100 (mg / l) or more, or 25 ° C. (pH = 11.95) represented by the general formula (I) ) A sensitizing dye having a solubility in an alkaline developer of 100 (mg / l) or more,
(B) an initiator compound capable of generating radicals, acids or bases,
(C) a polymerizable compound that reacts with at least one of a radical, an acid, and a base,
Among these, (A) a sensitizing dye and (B) an initiator compound capable of generating a radical, an acid or a base constitute a photoinitiating system of this photosensitive composition. In this system, (A) the initiator compound undergoes a chemical change by the action of electron transfer, energy transfer, heat generation, etc. due to the electronic excitation state caused by the light absorption of the sensitizing dye, thereby generating radicals, acids or bases.

Examples of the base used in the alkali developer include KOH, NaOH, K ₂ CO ₃ , KHCO ₃ and the like, but the base in the present invention is not limited to this, and the pH of the aqueous solution is 11.0 to 13. Includes everything that can be adjusted to zero.

  Hereinafter, a sensitizing dye having a solubility in an alkaline developer at 25 ° C. (pH = 11.95) of 100 (mg / l) or more is referred to as a specific dye. The solubility is more preferably 200 (mg / l) or more, and further preferably 300 (mg / l) or more. The solubility (dissolution amount) of (A) sensitizing dye in the present invention is 25 ° C. developer prepared at pH = 11.95 (an aqueous solution obtained by diluting DV-2 manufactured by Fuji Photo Film Co., Ltd. five times with water). ) The amount of sensitizing dye dissolved in an alkaline developer containing 98 ml of MEK and 2 ml.

First, this photoinitiating system will be described.
One of the characteristics of the (A) specific dye useful for the photoinitiating system of the present invention is that it has particularly excellent absorption characteristics in the 350 nm to 450 nm region. Furthermore, (A) a specific dye efficiently causes decomposition of various (B) initiator compounds and exhibits very high photosensitivity. In general, the sensitization mechanism of a photoinitiating system comprising a sensitizing dye / initiator compound is (a) reductive decomposition of an initiator compound based on an electron transfer reaction from an electronically excited state of the sensitizing dye to the initiator compound, b) Oxidative decomposition of initiator compound based on electron transfer from initiator compound to electronically excited state of sensitizing dye, (c) Initiation based on energy transfer from electronically excited state of sensitizing dye to initiator compound Although a route such as decomposition of an agent compound from an electronically excited state is known, it was found that the sensitizing dye of the present invention causes any of these types of sensitizing reactions with excellent efficiency.

  In order to obtain high sensitivity and high developability, the present inventors have a solubility of the sensitizing dye in an alkaline developer at 25 ° C. (pH = 11.95) of 100 (mg / l) or more. Has found that it is very important to have a partial structure represented by the general formula (I). The action mechanism is as described above. The reason why the sensitizing dye of the present invention is highly sensitive is that it exhibits a high-intensity emission (fluorescence and / or phosphorescence) spectrum. Is considered to have an effect on the efficiency of the reaction with the initiator compound since the lifetime of the excited state is relatively long. As another possibility, the partial structure represented by the general formula (I) contributes to the efficiency of the initial stage of the sensitization reaction (electron transfer, etc.) and the subsequent reaction leading to the decomposition of the initiator compound. There is also a possibility.

(A) Sensitizing dye The sensitizing dye used in the present invention has a solubility in an alkaline developer at 25 ° C. (pH = 11.95) of 100 (mg / l) or more, and is further represented by the following general formula (I): Those represented are preferred.

(In the general formula (I), A represents an aromatic ring or a hetero ring which may have a substituent, R ₁ represents a hydrogen atom or a monovalent nonmetallic atomic group. A and R ₁ are each They can be bonded to each other to form an aliphatic or aromatic ring, and Z represents a 5-membered or 6-membered ring structure containing a hetero atom.
The sensitizing dye represented by the general formula (I) has at least one COOR ₂ group, SO ₃ R ₃ group, PO at a site selected from a substituent on A, Z, R ₁ or R _{1. It} has a substituent selected from ₃ R ₄ group, OH group, and OCOR ₅ group. R ₂ , R ₃ , R ₄ , and R ₅ each independently represent a monovalent nonmetallic atomic group that is not a hydrogen atom. )

  Furthermore, it is more preferable that the sensitizing dye has a structure represented by the following general formula (II).

（一般式（ＩＩ）中、Ｒ₁、Ｒ₆〜Ｒ₁₁は、それぞれ独立に、水素原子または一価の非金属原子団を表し、Ｚはヘテロ原子を含む５員又は６員環構造を表す。
また一般式（ＩＩ）で表される増感色素は、Ｚ上の置換基と、Ｒ₁、Ｒ₆〜Ｒ₁₁上の置換基、又はＲ₁、Ｒ₆〜Ｒ₁₁から選ばれる部位に、少なくとも１つのＣＯＯＲ₂基、ＳＯ₃Ｒ₃基、ＰＯ₃Ｒ₄基、ＯＨ基、及びＯＣＯＲ₅基から選ばれる置換基を持つ。Ｒ₂、Ｒ₃、Ｒ₄、及びＲ₅は、それぞれ独立に、水素原子でない一価の非金属原子団を表す。）

(In general formula (II), R < ₁ >, R < ₆ > -R < ₁₁ > represents a hydrogen atom or a monovalent nonmetallic atomic group each independently, and Z represents the 5-membered or 6-membered ring structure containing a hetero atom. .
The sensitizing dye represented by the general formula (II) is a substituent on Z, a substituent on R ₁ , R _{6 to} R ₁₁ , or a site selected from R ₁ , R _{6 to} R ₁₁ . It has a substituent selected from at least one COOR ₂ group, SO ₃ R ₃ group, PO ₃ R ₄ group, OH group, and OCOR ₅ group. R ₂ , R ₃ , R ₄ , and R ₅ each independently represent a monovalent nonmetallic atomic group that is not a hydrogen atom. )

  Furthermore, it is most preferable that the sensitizing dye has a structure represented by the following general formula (III).

(In general formula (III), R < ₁ >, R < ₁₂ > -R < ₁₈ > represents a hydrogen atom or a monovalent nonmetallic atomic group each independently, X < ₁ > represents an oxygen atom, a sulfur atom, or -NR < ₁₉ >-. X ₂ represents an oxygen atom or NR _20. Each of R ₁₉ and R ₂₀ independently represents a monovalent nonmetallic atomic group that is not a hydrogen atom.
Further, the sensitizing dye represented by the general formula (III) includes a substituent on X ₁ , X ₂ and R ₁₈ , a substituent on R ₁ , R _{12 to} R ₁₈ , and R ₁ , R _{6 to} R. ₁₁ has a substituent selected from at least one COOR ₂ group, SO ₃ R ₃ group, PO ₃ R ₄ group, OH group, and OCOR ₅ group. R ₂ , R ₃ , R ₄ , and R ₅ each independently represent a monovalent nonmetallic atomic group that is not a hydrogen atom. )

  In the following, the above structural formula will be described in more detail.

Here, when R _{2 to} R ₅ represent a monovalent nonmetallic atomic group that is not a hydrogen atom, it preferably represents a substituted or unsubstituted alkyl group-substituted or unsubstituted aryl group. Further, here, when R ₁ and R _{6 to} R ₁₈ represent a monovalent nonmetallic atomic group that is not a hydrogen atom, it preferably represents a substituted or unsubstituted alkyl group or an alkoxy group, a substituted or unsubstituted aryl group. .

Next, preferred examples of R _{1 to} R ₁₈ will be specifically described. Examples of preferable alkyl groups include linear, branched, and cyclic alkyl groups having 1 to 20 carbon atoms. Specific examples thereof include a methyl group, an ethyl group, a propyl group, Butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, s-butyl, Examples thereof include t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group and 2-norbornyl group. Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

As the substituent of the substituted alkyl group, a monovalent non-metallic atomic group other than hydrogen is used. Preferred examples include halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups, alkoxy groups. 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-diaryl Amino 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, acyloxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N '-Arylureido 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-aryluree Id group, N′-alkyl-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 , 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 An alkylsulfinyl group, Arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfo group (—SO ₃ H) and its conjugate base group (hereinafter referred to as sulfonate group), alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkyls Rufinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkyl Sulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group (—PO ₃ H ₂₎ and its conjugated base group (hereinafter referred to as phosphonato group), di Rukiruhosuhono group _{(-PO 3 (alkyl) 2)} , diaryl phosphono group _{(-PO 3 (aryl) 2)} , alkyl aryl phosphono group _{(-PO 3 (alkyl) (aryl} )), monoalkyl phosphono group (- PO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkylphosphonate group), monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group (hereinafter referred to as arylphosphonato group) ), Phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonatooxy group), dialkylphosphonooxy group (—OPO ₃ (alkyl) ₂ ), diarylphosphonooxy group (—OPO _3). (aryl) _2), alkylaryl phosphono group _{(-OPO 3 (alkyl) (aryl} )), monoalkyl phosphonates Oxy group (-OPO ₃ H (alkyl)) and its conjugated base group (hereinafter referred to as alkylphosphonato group), monoarylphosphono group (-OPO ₃ H (aryl)) and its conjugated base group (hereinafter And cyano group, nitro group, aryl group, heteroaryl group, alkenyl group, alkynyl group, and silyl group.
Specific examples of the alkyl group in these substituents include the aforementioned alkyl groups, which may further have a substituent.

  Specific examples of the aryl group include phenyl group, biphenyl group, naphthyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group. , Ethoxyphenyl group, phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylaminophenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl Group, ethoxyphenylcarbonyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group, cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophene Group, can be exemplified phosphonophenyl phenyl group.

As the heteroaryl group, a group derived from a monocyclic or polycyclic aromatic ring containing at least one of nitrogen, oxygen and sulfur atoms is used, and examples of the heteroaryl ring in the particularly preferred heteroaryl group include Is, for example, thiophene, thiathrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indolizine, indazole, indazole, Purine, quinolidine, isoquinoline, phthalazine, naphthyridine, quinazoline, sinoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthrolin, phthalazine, phenalazine, phenoxazine, fura Emissions, and the like. These further may be benzo-fused or may have a substituent.

Examples of alkenyl groups include vinyl, 1-propenyl, 1-butenyl, cinnamyl, 2-chloro-1-ethenyl, etc. Examples of alkynyl include ethynyl, 1-butenyl, A propynyl group, a 1-butynyl group, a trimethylsilylethynyl group, etc. are mentioned. Examples of G ₁ in the acyl group (G ₁ CO—) include hydrogen and the above alkyl groups and aryl groups. Among these substituents, even more preferable are halogen atoms (—F, —Br, —Cl, —I), alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, N-alkylamino groups, N, N -Dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, formyl group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group Group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfa group Moyl group, N-arylsulfur Amoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group, phosphonato group, dialkylphosphono group, diarylphosphono group, monoalkylphosphono group, alkylphosphonato group, monoarylphosphono group, arylphospho Examples thereof include a nato group, a phosphonooxy group, a phosphonatoxy group, an aryl group, an alkenyl group, and an alkylidene group (such as a methylene group).

  On the other hand, examples of the alkylene group in the substituted alkyl group include divalent organic residues obtained by removing any one of the hydrogen atoms on the alkyl group having 1 to 20 carbon atoms. Can include linear alkylene groups having 1 to 12 carbon atoms, branched chains having 3 to 12 carbon atoms, and cyclic alkylene groups having 5 to 10 carbon atoms.

Specific examples of preferred substituted alkyl groups as R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ obtained by combining the above substituents with an alkylene group include chloromethyl, bromomethyl and 2-chloroethyl. Group, trifluoromethyl group, methoxymethyl group, methoxyethoxyethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl Group, benzoyloxymethyl group, N-cyclohexylcarbamoyloxyethyl group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group Methoxycarbonylethyl group, allyloxycarbonylbutyl group, chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N- Methyl-N- (sulfophenyl) carbamoylmethyl group, sulfobutyl group, sulfonatopropyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N -Tolylsulfamoylpropyl group, N-methyl-N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphine Phonobutyl group, methylphosphonatobutyl group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonatoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1 -Phenylethyl group, p-methylbenzyl group, cinnamyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl group, 2-butynyl group, A 3-butynyl group etc. can be mentioned.

Preferred alkoxy groups for R ₁ and R _{6 to} R ₁₈ include linear, branched and cyclic alkoxy groups having 1 to 20 carbon atoms, and the substituents present on the alkoxy groups As the above, the same substituents as those on the alkyl group described above can be exemplified. Specific examples thereof include a methoxy group and an ethoxy group, and a methoxy group is particularly preferable.

Specific examples of preferred aryl groups as R _{1 to} R ₁₈ include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group. Among these, a phenyl group and a naphthyl group are more preferable.

Specific examples of the preferred substituted aryl group as R _{1 to} R ₁₈ include those having a monovalent nonmetallic atomic group (other than a hydrogen atom) as a substituent on the ring-forming carbon atom of the aryl group. Used. Examples of preferred substituents include the alkyl groups, substituted alkyl groups, and those previously shown as substituents in the substituted alkyl group. Preferred examples of such a substituted aryl group include biphenyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, fluorophenyl group, chloromethylphenyl group, trifluoromethylphenyl group. Hydroxyphenyl group, methoxyphenyl group, methoxyethoxyphenyl group, allyloxyphenyl group, phenoxyphenyl group, methylthiophenyl group, tolylthiophenyl group, ethylaminophenyl group, diethylaminophenyl group, morpholinophenyl group, acetyloxyphenyl group, Benzoyloxyphenyl group, N-cyclohexylcarbamoyloxyphenyl group, N-phenylcarbamoyloxyphenyl group, acetylaminophenyl group, N-methylbenzoylaminophenyl group, cal Xiphenyl group, methoxycarbonylphenyl group, allyloxycarbonylphenyl group, chlorophenoxycarbonylphenyl group, carbamoylphenyl group, N-methylcarbamoylphenyl group, N, N-dipropylcarbamoylphenyl group, N- (methoxyphenyl) carbamoylphenyl group N-methyl-N- (sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoylphenyl group, N-ethylsulfamoylphenyl group, N, N-dipropylsulfamoylphenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phosphonophenyl group, phosphonatophenyl group, diethylphosphonophenyl group, diphenylphosphoro Phenyl group, methylphosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group, tolylphosphonatephenyl group, allylphenyl group, 1-propenylmethylphenyl group, 2-butenylphenyl group, 2-methylallylphenyl Group, 2-methylpropenylphenyl group, 2-propynylphenyl group, 2-butynylphenyl group, 3-butynylphenyl group and the like.

Preferred examples of R ₁ include a hydrogen atom, preferred examples of R _{2 to} R ₅ include a substituted or unsubstituted alkyl group, and preferred examples of R _{8 to} R ₁₈ include a hydrogen atom. A substituted or unsubstituted alkyl group, and a substituted or unsubstituted alkoxy group. Preferable examples of R ₆ and R ₇ include a substituted or unsubstituted alkyl group and a substituted or unsubstituted alkoxy group. R ₆ and R ₇ are more preferably substituted alkyl having 2 or more carbon atoms. When the sensitizing dye having the structure in the present invention has an alkyl structure with a small number of carbon atoms from N, it has a characteristic that the absorption wavelength is shortened. For this reason, carbon number becomes like this. Preferably it is 2, More preferably, it is 3.

  Moreover, since the sensitizing dye in the present invention has a hydrophilic group (such as an ester group, a phosphate group, or a hydroxyl group) on the structure, it can be kept in a dissolved state without being precipitated in the developer. At this time, the hydrophilic group is particularly preferably a hydroxyl group or an acetyl group, and more preferably an acetyl group. The two hydrophilic groups have particularly high ability to impart developer solubility to sensitizing dyes. However, if the photosensitive layer is formed with the hydroxyl group exposed, the film strength after exposure and curing is lowered (developer permeability is increased), and thus an acetyl group protected is preferred. The acetyl group is easily hydrolyzed by an alkaline developer at 25 ° C. (PH = 11.95), and the developer solubility is substantially maintained.

Further, by making X _{2 an} oxygen atom, the developer solubility of the sensitizing dye is further improved. This is considered because the cyclic ester portion is hydrolyzed. However, depending on the type of the initiator, there is an influence on the sensitivity. From the viewpoint of sensitivity, it is preferable to use a sensitizing dye whose X ₂ is NR ₂₀ with respect to the hexaarylbiimidazole initiator.

  By using the above-mentioned hydrophilic group, the printing plate produced in the present invention causes the dye component to precipitate from the developer even when a large amount of the photosensitive layer component is dissolved in the developer, thereby fouling the developing machine. There is no. In other words, it is very useful because it can minimize the load on maintenance of the equipment, reduce the cost and improve the workability.

Next, A in the general formula (I) will be described. A represents an aromatic ring or a hetero ring which may have a substituent. Specific examples of the aromatic ring or hetero ring which may have a substituent include substitution of a substituted alkyl group in formula (I) The thing similar to what was illustrated as group is mentioned.
Among them, preferable A includes an alkoxy group, a thioalkyl group, and an aryl group having an amino group, and more preferable A includes an aryl group having an amino group. Particularly preferred aryl groups having an amino group include a dialkylaminoaryl group and a diarylaminoaryl group which may have a substituent. Specifically, a dimethylaminophenyl group which may have a substituent, A diethylaminophenyl group, a piperidinophenyl group, a morpholinophenyl group, a julolidine group, a diphenylaminophenyl group and the like can be mentioned.

  Preferred specific examples (Exemplary Compound D1 to Exemplified Compound D33) of the sensitizing dyes represented by the general formulas (I), (II) and (III) according to the present invention are shown below, but the present invention is limited to these. Is not to be done.

A method for synthesizing the compound represented by the general formula (I) will be described.
The compound represented by the general formula (I) is usually obtained by a condensation reaction between an acidic nucleus having an active methylene group and a substituted or unsubstituted aromatic ring or heterocyclic ring. It can synthesize | combine with reference to a gazette. For example, as shown in the following reaction formula, a synthesis method using a condensation reaction of an acidic nucleus compound and a basic nucleus raw material having an aldehyde group or a carbonyl group on the heterocycle can be mentioned. The condensation reaction is carried out in the presence of a base, if necessary. Examples of the base include those generally used, such as amines, pyridines (trialkylamine, dimethylaminopyridine, diazabicycloundecene DBU, etc.), metal amides (lithium diisopropylamide, etc.), metal alkoxides ( Sodium methoxide, potassium-t-butoxide, etc.) and metal hydrides (sodium hydride, potassium hydride, etc.) can be used without limitation.

The details of the reaction in the above reaction are as follows.
(Synthesis of D-1: Preparation)
0.005 mol of t-BuOK was added to the aldehyde compound (0.01 mol), heterocycle (0.01 mol), and THF (solvent, 1M), and refluxed at 70 ° C. for 1 hour. Extracted with water (200 ml) -ethyl acetate (200 ml * 3), dried over MgSO ₄ , and concentrated using an evaporator. The concentrate was subjected to column chromatography with ethyl acetate-hexane to obtain the desired product (D-1, 0.006 mol).

  The sensitizing dye represented by the general formula (I) used in the present invention can be further subjected to various chemical modifications for improving the characteristics of the photosensitive layer. For example, the exposure film can be strengthened by bonding a sensitizing dye and an addition polymerizable compound structure (for example, acryloyl group or methacryloyl group) by a method such as covalent bond, ionic bond, or hydrogen bond. it can.

  In addition, partial structures having radical generating ability in sensitizing dyes and initiator compounds described later (for example, reductive decomposable sites such as alkyl halides, oniums, peroxides, biimidazoles, oniums, biimidazoles, borates, amines) , Trimethylsilylmethyl, carboxymethyl, carbonyl, imine, and other oxidatively cleavable moieties) can significantly increase the photosensitivity particularly in a low concentration of the starting system.

  In addition, for example, a substituent can be appropriately introduced in order to improve compatibility in the photosensitive layer and to suppress crystal precipitation. For example, in certain types of photosensitive systems, unsaturated bonds such as aryl groups and allyl groups may be very effective in improving compatibility. By introducing an obstacle, crystal precipitation can be remarkably suppressed. In addition, by introducing a phosphonic acid group, an epoxy group, a trialkoxysilyl group, or the like, adhesion to an inorganic substance such as a metal or a metal oxide can be improved. In addition, a method such as polymerization of a sensitizing dye can be used depending on the purpose.

  As the sensitizing dye used in the present invention, at least one sensitizing dye represented by the above general formula (I) may be used. As long as it is represented by this general formula (I), for example, the modification described above may be used. The details of the usage, such as the structure of the dye used, whether it is used alone or in combination of two or more, and how much is added, are in line with the performance design of the final photosensitive material. It can be set appropriately. For example, the compatibility with the photosensitive layer can be increased by using two or more sensitizing dyes in combination.

  In selecting the sensitizing dye, in addition to the photosensitivity, the molar extinction coefficient at the emission wavelength of the light source used is an important factor. By using a dye having a large molar extinction coefficient, the amount of the dye added can be made relatively small, which is economical and advantageous from the viewpoint of film properties of the photosensitive layer.

  In the present invention, in addition to the specific sensitizing dye (A), other general-purpose sensitizing dyes can be used in combination as long as the effects of the present invention are not impaired.

  Since the photosensitivity and resolution of the photosensitive layer and the physical properties of the exposure film are greatly affected by the absorbance at the light source wavelength, the addition amount of the sensitizing dye is appropriately selected in consideration of these. For example, the sensitivity decreases in a low region where the absorbance is 0.1 or less. Also, the resolution becomes low due to the influence of halation. However, for the purpose of curing a thick film of, for example, 5 μm or more, there is a case where such a low absorbance can be increased instead. In the region where the absorbance is 3 or more, most of the light is absorbed on the surface of the photosensitive layer, and the internal curing is inhibited. For example, when used as a printing plate, the film strength and the substrate adhesion are poor. It will be insufficient.

For example, when the photosensitive composition of the present invention is used in the photosensitive layer of a lithographic printing plate precursor using a relatively thin film thickness, the amount of the sensitizing dye added is such that the absorbance of the photosensitive layer is 0.1 to 1. .5, preferably 0.25 to 1. Since the absorbance is determined by the addition amount of the sensitizing dye and the thickness of the photosensitive layer, the predetermined absorbance can be obtained by controlling both conditions. The absorbance of the photosensitive layer can be measured by a conventional method. As a measuring method, for example, on a transparent or white support, a photosensitive layer having a thickness appropriately determined in a range where the coating amount after drying is necessary as a lithographic printing plate is formed, and a transmission type optical densitometer is used. Examples thereof include a method of measuring, a method of forming a photosensitive layer on a reflective support such as aluminum, and measuring a reflection density.

  When the photosensitive composition of the present invention is used as a photosensitive layer of a lithographic printing plate precursor, the sensitizing dyes represented by the general formula (I) (general formulas (II) and (III) are represented by the general formula (I) The amount of the sensitizing dye represented by the formula (1) is usually 0.05 to 30 parts by mass, preferably 0 with respect to 100 parts by mass of the total solid components constituting the photosensitive layer. .1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass.

Next, (B) the initiator compound, which is the second essential component of the photoinitiating system in the photosensitive composition of the present invention, will be described.
(B) Initiator Compound The initiator compound in the present invention is a compound that generates a radical, an acid, or a base by causing a chemical change through interaction with an electronically excited state generated by light absorption of a sensitizing dye. Hereinafter, the radical, acid or base generated in this way is simply referred to as an active species. When these compounds are not present or when only the initiator compound is used alone, practically sufficient sensitivity cannot be obtained, but as one aspect of using the sensitizing dye and the initiator compound in combination, These can also be used as a single compound by an appropriate chemical method (such as linking of a sensitizing dye and an initiator compound through a chemical bond). Such a technical idea is disclosed in, for example, Japanese Patent No. 2720195.

  Usually, many of these active agents are considered to generate active species through the following initial chemical processes (1) to (3). That is, (1) reductive decomposition of an initiator compound based on an electron transfer reaction from an electronically excited state of a sensitizing dye to an activator, and (2) an electron transfer from the initiator compound to the electronically excited state of the sensitizing dye. Oxidative decomposition of the initiator compound based on (3) decomposition of the initiator compound from the electronically excited state based on energy transfer from the electronically excited state of the sensitizing dye to the initiator compound. Although it is often ambiguous as to which type (1) to (3) each individual initiator compound belongs, the major feature of the sensitizing dye in the present invention is any of these types of initiators. Even when combined with a compound, it has a very high sensitizing effect.

Specific initiator compounds known to those skilled in the art can be used without limitation. Specifically, for example, Bruce M. et al. Monroe et al., Chemical Review, 93, 435 (1993) and R.C. S. Davidson, Journal of Photochemistry and biologic A: Chemistry, 73.81 (1993); P. Faussier, “Photoinitiated
Polymerization-Theory and Applications ": Rapra Review vol.9, Report, Rapra Technology (1998); M. Tsunooka et al., Prog.Poly. As other compounds having the functions (1) and (2), FD Saeva, Topics in Current Chemistry, 156, 59 (1990); 168, 1 (1993); H. B. Shuster et al, JACS,
112, 6329 (1990); D. F. A group of compounds that cause oxidative or reductive bond cleavage is also known, as described in Eaton et al, JACS, 102, 3298 (1980).

  The following are specific examples of preferred initiator compounds: (a) those that are reduced to cause bond cleavage to produce active species, (b) those that can be oxidized to cause bond cleavage to produce active species, and ( c) Others are classified and explained, but there are many cases where there is no general explanation as to which individual compounds belong to them, and the present invention is not limited to the description of these reaction mechanisms.

(A) Compound that is reduced to cause bond cleavage to generate an active species Compound having a carbon-halogen bond: It is considered that a carbon-halogen bond is reductively cleaved to generate an active species (for example, Polymer Preprints, Jpn., 41 (3) 542 (1992)). As the active species, radicals and acids can be generated. Specifically, for example, in addition to halomethyl-s-triazines, M.M. P. Hutt, E .; F. Elslager and L.L. M.M. By Merbel, Journal of
Heteromethyloxadiazoles which can be easily synthesized by those skilled in the art by the synthesis method described in Heterocyclic Chemistry, 7, 511 (1970), and German Patent Nos. 2641100, 3333450, 3021590, and 3021599. The compounds described in each specification can be preferably used.

  Compound having nitrogen-nitrogen bond or nitrogen-containing heterocycle-nitrogen-containing heterocycle bond: reductive bond cleavage (for example, described in J. Pys. Chem., 96, 207 (1992)) . Specifically, hexaarylbiimidazoles and the like are preferably used. The generated active species is a lophine radical, and in combination with a hydrogen donor as necessary, a radical chain reaction is initiated, and image formation using an oxidation reaction with a lophine radical is also known (J. Imaging Sci., 30). 215 (1986)).

Compound having oxygen-oxygen bond: It is considered that the oxygen-oxygen bond is reductively cleaved to generate an active radical (for example, Polym. Adv. Technol., 1, 287).
(1990)). Specifically, for example, organic peroxides are preferably used. A radical can be generated as an active species.

Onium compound: It is considered that a carbon-hetero bond or oxygen-nitrogen bond is reductively cleaved to generate an active species (for example, J. Photopolym. Sci. Technol.,
3, 149 (1990)). Specifically, for example, iodonium salts described in European Patent No. 104143, US Pat. No. 4,837,124, Japanese Patent Laid-Open No. 2-150848, Japanese Patent Laid-Open No. 2-96514, European Patent Nos. 370693 and 233567. Sulfonium salts described in U.S. Pat. Nos. 297443, 297442, 279210, 422570, U.S. Pat.Nos. 3,902,144, 4,933,377, 4760013, 4,734,444 and 2,833,827, Diazonium salts (such as benzenediazonium which may have a substituent), diazonium salt resins (formaldehyde resin of diazodiphenylamine, etc.), N-alkoxypyridinium salts, etc. (for example, US Pat. No. 4,743,528, Kaisho 63-13834 No. 63-142345, JP-A 63-142346, JP-B 46-42363, etc., specifically 1-methoxy-4-phenylpyridinium tetrafluoroborate, etc. And compounds described in JP-B Nos. 52-147277, 52-14278, and 52-14279 are preferably used. Generates radicals and acids as active species.

Active esters: nitrobenzyl esters of sulfonic acid and carboxylic acid, esters of sulfonic acid and carboxylic acid and N-hydroxy compounds (N-hydroxyphthalimide, oxime, etc.), sulfonic acid esters of pyrogallol, naphthoquinone diazide-4 -Sulfonates can be reductively decomposed. As the active species, radicals and acids can be generated. Specific examples of the sulfonic acid esters include European Patent Nos. 0290750, 046083, 1156153, 271851, 0388343, U.S. Pat. Nos. 3,901,710 and 4,181,531, JP-A-60-198538. No., JP-A-53-13302
Nitrobenzester compounds described in each publication No. 2, European Patent Nos. 0199672, 84515, 199672, 0441115, 0101122, U.S. Pat. Nos. 4,618,564, 4,371,605 and 4,431,774 , JP-A-64-18143, JP-A-2-245756, JP-A-4-365048, iminosulfonate compounds, JP-B-62-2223, JP-B-63-14340, JP-A-59. -174831 each compound etc. are mentioned, Furthermore, the compound as shown below is mentioned, for example.

(In the formula, Ar represents an aromatic group or an aliphatic group which may be substituted.)

  Moreover, it is also possible to produce | generate a base as an active species, for example, the following compound groups are known.

  Ferrocene and iron arene complexes: An active radical can be reductively generated. Specifically, for example, they are disclosed in JP-A-1-304453 and JP-A-1-152109.

  (In the formula, R represents an aliphatic group or an aromatic group which may be substituted.)

  Disulfones: Reducing S—S bond reductively and generating an acid. For example, diphenyl disulfones as described in JP-A No. 61-166544 are known.

(B) Oxidized to generate active species by cleaving bond Alkylate complex: It is considered that a carbon-hetero bond is oxidatively cleaved to generate an active radical (for example, J. Am. Chem. Soc ., 112, 6329 (1990)). Specifically, for example, triarylalkyl borates are preferably used.

  Alkylamine compound: It is considered that the C—X bond on carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical (see, for example, J. Am. Chem. Soc., 116, 4211 (1994)). be written). X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, a benzyl group or the like. Specific examples include ethanolamines, N-phenylglycines, N-trimethylsilylmethylanilines, and the like.

  Sulfur-containing and tin-containing compounds: Compounds in which the nitrogen atoms of the above-described amines are replaced with sulfur atoms and tin atoms can generate active radicals by the same action. Further, a compound having an SS bond is also known to be sensitized by SS cleavage.

  α-Substituted methylcarbonyl compound: An active radical can be generated by oxidative cleavage of the carbonyl-α carbon bond. Moreover, what converted carbonyl into the oxime ether also shows the same effect | action. Specifically, 2-alkyl-1- [4- (alkylthio) phenyl] -2-morpholinopronone-1 and these and a hydroxylamine were reacted, and then N—OH was etherified. Mention may be made of oxime ethers.

  Sulfinic acid salts: An active radical can be reductively generated. Specific examples include sodium arylsulfinate.

(C) Others Although the sensitization mechanism is not clear, many of them can function as initiator compounds. Titanocene,
Examples include organometallic compounds such as ferrocene, aromatic ketones, acylphosphine, and bisacylphosphine. Active species can generate radicals and acids.

  Hereinafter, among the initiator compounds used in the present invention, preferred compounds particularly excellent in sensitivity and stability are specifically exemplified.

(1) Halomethyltriazines Examples include compounds represented by the following formula [II]. Excellent radical generation and acid generation ability.

In the formula [II], X represents a halogen atom. Y ¹ represents —C (X) ₃ , —NH ₂ , —NHR ¹ ′, —NR ¹ ′ ₂ , —OR ¹ ′. Here, R ¹ ′ represents an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group. R ¹ represents —CX ₃ , an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, or a substituted alkenyl group.

  Specific examples of such compounds include, for example, compounds described in Wakabayashi et al., Bull. Chem. Soc. Japan, 42, 2924 (1969), such as 2-phenyl-4,6-bis (trichloromethyl)- S-triazine, 2- (p-chlorophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (p-tolyl) -4,6-bis (trichloromethyl) -S-triazine, 2 -(P-methoxyphenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (2 ', 4'-dichlorophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2,4,6-tris (trichloromethyl) -S-triazine, 2-methyl-4,6-bis (trichloromethyl) -S-triazine, 2-n-nonyl-4,6-bis (trichloromethyl)- S- Triazine, 2- (α, α, β- trichloroethyl) -4,6-bis (trichloromethyl) -S- triazine. In addition, compounds described in GB 1388492, for example, 2-styryl-4,6-bis (trichloromethyl) -S-triazine, 2- (p-methylstyryl) -4,6-bis (trichloromethyl) ) -S-triazine, 2- (p-methoxystyryl) -4,6-bis (trichloromethyl) -S-triazine, 2- (p-methoxystyryl) -4-amino-6-trichloromethyl-S-triazine Compounds described in JP-A-53-133428, such as 2- (4-methoxy-naphth-1-yl) -4,6-bis-trichloromethyl-S-triazine, 2- (4-ethoxy- Naphth-1-yl) -4,6-bis-trichloromethyl-S-triazine, 2- [4- (2-ethoxyethyl) -naphth-1-yl] -4,6-bis-tri Lormethyl-S-triazine, 2- (4,7-dimethoxy-naphth-1-yl) -4,6-bis-trichloromethyl-S-triazine, 2- (acenaphtho-5-yl) -4,6-bis Examples include compounds described in German Patent No. 3333724, such as -trichloromethyl-S-triazine, and the like.

  Further, compounds described in J. Org. Chem., 29, 1527 (1964) by FC Schaefer et al., For example, 2-methyl-4,6-bis (tribromomethyl) -S-triazine, 2,4,6-tris (Tribromomethyl) -S-triazine, 2,4,6-tris (dibromomethyl) -S-triazine, 2-amino-4-methyl-6-tribromomethyl-S-triazine, 2-methoxy-4-methyl And -6-trichloromethyl-S-triazine.

  Further, compounds described in JP-A-62-258241, for example, the following compounds can be mentioned.

  Further, compounds described in JP-A-5-281728, for example, the following compounds can be mentioned.

(2) Titanocenes Any titanocene compound that is particularly preferably used as an initiator compound may be any titanocene compound that can generate active species when irradiated with light in the presence of the sensitizing dye. Well, for example, JP-A-59-152396, JP-A-61-151197, JP-A-63-41483, JP-A-63-41484, JP-A-2-249, JP-A-2-291, Known compounds described in JP-A-3-27393, JP-A-3-12403, and JP-A-6-41170 can be appropriately selected and used.

  More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5 , 6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2 , 4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4 -Difluorophenyl-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti- Bis-2, 3, , 6-tetrafluorophenyl-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis (2,6- And difluoro-3- (pyr-1-yl) phenyl) titanium.

(3) Borate salt compounds Borate salts represented by the following formula [III] are excellent in radical generating ability.

In the formula [III], R ⁵¹ , R ⁵² , R ⁵³ and R ⁵⁴ may be the same or different from each other, and each represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkenyl. A group, a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted heterocyclic group, wherein R ⁵¹ , R ⁵² , R ^53, and R ⁵⁴ are bonded to form a cyclic structure. Also good. However, at least one of R ⁵¹ , R ⁵² , R ⁵³ and R ⁵⁴ is a substituted or unsubstituted alkyl group. Z ⁺ represents an alkali metal cation or a quaternary ammonium cation.

The alkyl groups of R ^{51 to} R ⁵⁴ include straight chain, branched, and cyclic groups, and those having 1 to 18 carbon atoms are preferable. Specifically, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, octyl, stearyl, cyclobutyl, cyclopentyl, cyclohexyl and the like are included. Examples of the substituted alkyl group include the above alkyl groups, halogen atoms (for example, -Cl, -Br, etc.), cyano groups, nitro groups, aryl groups (preferably phenyl groups), hydroxy groups, the following groups,

(Shown here the R ^55, R ⁵⁶ are independently hydrogen, an alkyl group of 1 to 14 carbon atoms or an aryl group,.), - COOR ⁵⁷ (where R ⁵⁷ is a hydrogen atom, the number 1 to 14 carbon An alkyl group or an aryl group), -COOR ⁵⁸ or -OR ⁵⁹ (wherein R ⁵⁸ and R ⁵⁹ each independently represents an alkyl group having 1 to 14 carbon atoms or an aryl group); What has as a substituent is contained.

Examples of the aryl group of R ^{51 to} R ⁵⁴ include 1 to 3 ring aryl groups such as a phenyl group and a naphthyl group, and examples of the substituted aryl group include the substitution of the above substituted alkyl group with the above aryl group. And those having an alkyl group having 1 to 14 carbon atoms.

Examples of the alkenyl group represented by R ^{51 to} R ⁵⁴ include linear, branched, and cyclic groups having 2 to 18 carbon atoms, and examples of the substituent of the substituted alkenyl group include the substituents of the substituted alkyl group. Is included.

Examples of the alkynyl group of R ^{51 to} R ⁵⁴ include linear or branched groups having 2 to 28 carbon atoms, and examples of the substituent of the substituted alkynyl group include those listed as the substituent of the substituted alkyl group. included.

In addition, examples of the heterocyclic group of R ^{51 to} R ⁵⁴ include a 5- or more-membered heterocyclic group containing at least one of N, S and O, preferably a 5- to 7-membered heterocyclic group. May contain a condensed ring. Furthermore, you may have what was mentioned as a substituent of the above-mentioned substituted aryl group as a substituent.

  Specific examples of the compound represented by the formula [III] include compounds described in the specifications of U.S. Pat. Nos. 3,567,453 and 4,434,891, European Patent Nos. 109772 and 109773, and those shown below. Can be mentioned.

(4) Hexaarylbiimidazoles Excellent in stability and capable of generating highly sensitive radicals. Specifically, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4', 5,5'-tetraphenylbiimidazole 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5 '-Tetraphenylbiimidazole, 2,2'-bis (o-trifluoromethyl Eniru) -4,4 ', 5,5'-tetraphenyl biimidazole.

(5) Onium salt compounds 15 (5B), 16 (6B), and 17 (7B) group elements of the periodic table, specifically N, P, As, Sb, Bi, O, S, Se, Te, I The onium compound is an initiator compound having excellent sensitivity. Particularly, iodonium salts and sulfonium salts, particularly diaryl iodonium and triaryl sulfonium salt compounds are extremely excellent in terms of both sensitivity and storage stability. Acids and / or radicals can be generated, and these can be used properly by appropriately selecting the use conditions according to the purpose. Specific examples include the following compounds.

(6) Organic peroxide When an organic peroxide type initiator compound is used, radicals can be generated as active species with very high sensitivity.

The organic peroxide used in the present invention includes almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. Examples thereof include methyl ethyl ketone peroxide, cyclohexanone peroxide, 3, 3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxide Oxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paraffin hydroperoxide, 2,5-dimethylhexane 2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, bis (t-butylperoxide Oxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, acetyl peroxide , Isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, Meta-toluoyl peroxide, diisopropyl par Xydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, t-butyl Peroxyacetate, t-butylperoxypivalate, t-butylperoxyneodecanoate, t-butylperoxyoctanoate, t-butylperoxy-3,5,5-trimethylhexanoate, t- Butyl peroxylaurate, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butyl maleic acid peroxide, t -Butyl peroxyisopropyl carbonate, 3 , 3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (t-amylperoxycarbonyl) benzophenone, 3,3 ′, 4, 4′-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (t-octylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (cumylperoxy) Carbonyl) benzophenone, 3,3 ′, 4,4′-tetra (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogendiphthalate), carbonyldi (t-hexylperoxydihydrogen) Diphthalate).

Among these, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (t-amylperoxycarbonyl) benzophenone, 3 , 3 ′, 4,4′-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (t-octylperoxycarbonyl) benzophenone, 3,3 ′, 4,4 ′ Peroxide esters such as tetra (cumylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (p-isopropylcumylperoxycarbonyl) benzophenone, di-t-butyldiperoxyisophthalate are preferred. .
Preferable examples of the initiator compound include titanocene compounds, triazine compounds, and hexaarylbiimidazole compounds, and particularly preferable initiator compounds include hexaarylbiimidazole compounds.

  The initiator compound described above can be subjected to various chemical modifications for improving the characteristics of the photosensitive layer as in the case of the sensitizing dye. For example, bonding with sensitizing dyes, addition-polymerizable unsaturated compounds and other initiator compound parts, introduction of hydrophilic sites, compatibility improvement, introduction of substituents for suppressing crystal precipitation, substituents for improving adhesion Methods such as introduction and polymerization can be used.

The usage method of these initiator compounds can be arbitrarily set arbitrarily according to the performance design of the light-sensitive material, as in the case of the sensitizing dye described above. For example, by using two or more kinds in combination, the compatibility with the photosensitive layer can be increased.
A larger amount of the initiator compound is usually advantageous in terms of photosensitivity, and is used in a range of 0.5 to 80 parts by weight, preferably 1 to 50 parts by weight, with respect to 100 parts by weight of the photosensitive layer component. Sufficient photosensitivity can be obtained.

(C) Polymerizable compound The third essential component “(C) polymerizable compound that reacts with at least one of a radical, an acid, and a base” in the photosensitive composition of the present invention is obtained by a photoreaction of the above-described photoinitiating system. It is a compound that causes irreversible changes in its physical or chemical properties due to the action of the generated active species and causes a curing reaction, color development, decoloring reaction, etc. Any compound can be used, and for example, the compounds listed in the above-mentioned starting system often have such properties.
As the characteristics of the polymerizable compound (C) that changes depending on radicals, acids, and / or bases generated from the photoinitiating system, for example, molecular properties such as absorption spectrum (color), chemical structure, polarizability, It includes changes in material properties such as solubility, strength, refractive index, fluidity, and adhesiveness.

  For example, if a compound whose absorption spectrum changes with pH, such as a pH indicator, is used as the component (C) polymerizable compound and an acid or base is generated from the initiation system, the color tone can be changed only in the exposed area. Such a composition is useful as an image forming material. Similarly, when a compound whose absorption spectrum is changed by oxidation / reduction or nucleophilic addition reaction is used as the polymerizable compound (C), it is possible to form an image by causing oxidation or reduction by radicals generated from the initiation system. . Such examples include, for example, J. Am. Chem. Soc., 108, 128 (1986), J. Imaging. Soc., 30, 215 (1986), Israel. J. Chem., 25, 264. (1986).

  Among these, a photocurable resin or a negative photopolymer can be formed by using a compound capable of addition polymerization or polycondensation as the polymerizable compound (C) and combining it with an initiation system. Such a composition is also useful as a negative photosensitive layer of a lithographic printing plate precursor.

  Examples of such polymerizable compound (C) include radical polymerizable compounds (such as compounds having an ethylenically unsaturated bond), cationic polymerizable compounds (such as epoxy compounds, vinyl ether compounds, and methylol compounds), and anionic polymerizable compounds (such as epoxy). Examples of such compounds are described in, for example, Photopolymer Social Association, Photopolymer Handbook, Kogyo Kenkyukai (1989), Polymer, Vol. 45, 786 (1996), etc. . In addition, a composition in which a thiol compound is used as the polymerizable compound (C) and combined with a photoradical generation system is also well known.

  (C) It is also useful to use an acid-decomposable compound as the polymerizable compound and combine it with a photoacid generator. For example, a material that uses a polymer whose side chain or main chain is decomposed by an acid and changes its solubility or hydrophilicity / hydrophobicity by light is widely used as a photodegradable photosensitive resin or a positive photopolymer. Such specific examples include, for example, ACS. Symp. Ser. 242, 11 (1984), JP-A-60-3625, U.S. Pat. Nos. 5102771, 5206317, 5212047, and JP-A-4. -26850, JP-A-3-1921731, JP-A-60-10247, JP-A-62-245050 and the like.

  For the purpose of obtaining a highly sensitive lithographic printing plate precursor, which is one of the main uses of the photosensitive composition of the present invention, an addition polymerizable compound (C) which is a polymerizable compound is used below. Take this case as an example and explain in more detail.

(C-1) Addition polymerizable compound An addition polymerizable compound having at least one ethylenically unsaturated double bond, which is a preferred polymerizable compound (C) used in the present invention, has a terminal ethylenically unsaturated bond. It is selected from compounds having at least 1, preferably 2 or more. Such compound groups are widely known in the industrial field, and these can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, unsaturated carboxylic acid ester having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group, amide and monofunctional or polyfunctional isocyanate, addition reaction product of epoxy, monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. In addition, an unsaturated carboxylic acid ester having an electrophilic substituent such as an isocyanato group or an epoxy group, an addition reaction product of an amide with a monofunctional or polyfunctional alcohol, an amine or a thiol, a halogen group Also suitable are substitution reaction products of unsaturated carboxylic acid esters, amides with monofunctional or polyfunctional alcohols, amines, and thiols having a leaving substituent such as a tosyloxy group. 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, Those having an aromatic skeleton described in JP-A-59-5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used.
The aforementioned ester monomers 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 No. 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 (V) to a polyisocyanate compound having two or more isocyanate groups. Compounds and the like.

_{CH 2 = C (R) COOCH} 2 CH (R ') OH (V)
(However, R and R ′ represent H or CH _3. )

  Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, 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, JP-A-1-105238 Can obtain a photosensitive composition having a very high photosensitive speed.

  Other examples include reacting polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191 and JP-B-52-30490. And polyfunctional acrylates and methacrylates such as epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid compounds described in JP-A-2-25493 are also included. be able to. 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 addition polymerizable compounds, the details of usage, such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints. From the viewpoint of photosensitive speed, a structure having a high unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image 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 acid ester, methacrylic acid ester, styrenic compound, vinyl ether type). A method of adjusting both photosensitivity and intensity by using a 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 in the photosensitive layer (for example, binder polymer, initiator, colorant, etc.). The compatibility may be improved by using a low-purity compound or using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving the adhesion of the substrate and an overcoat layer described later. As for the compounding ratio of the addition polymerizable compound in the photosensitive layer, a larger amount is advantageous in terms of sensitivity, but if it is too much, undesirable phase separation occurs or a problem in the production process due to the adhesiveness of the photosensitive layer. For example, problems such as transfer of photosensitive layer components and manufacturing defects due to adhesion, and precipitation from the developer may occur. From these viewpoints, the addition polymerizable compound is preferably used in the range of 5 to 80% by mass, and more preferably 25 to 75% by mass with respect to the nonvolatile component in the photosensitive layer. These may be used alone or in combination of two or more. In addition, the use method of the addition polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. Depending on the case, a layer configuration and coating method such as undercoating and overcoating can be performed.

  (C) The content in the case of using a compound other than the (C-1) addition polymerizable compound as the polymerizable compound can be appropriately selected as appropriate depending on the intended property change or the compound used. Specifically, when a compound whose absorption spectrum is changed by oxidation / reduction or nucleophilic addition reaction is used, it is preferably about 10 to 80% by mass in the total solid content of the composition.

(D) Binder polymer In application to the photosensitive layer of a lithographic printing plate precursor which is a preferred embodiment of the photosensitive composition of the present invention, a binder polymer is further used in the photosensitive composition from the viewpoint of improving film properties. It is preferable to do.
As the binder polymer, it is preferable to contain a linear organic polymer. As such a “linear organic polymer”, any compound may be used, but preferably water or weak alkaline water soluble or swellable that enables water development or weak alkaline water development. A linear organic polymer is selected. The linear organic high molecular polymer is selected and used not only as a film-forming agent for the composition but also according to its use as water, weak alkaline water or an organic solvent developer. For example, when a water-soluble organic polymer is used, water development is possible. Examples of such linear organic high molecular polymers include addition polymers having a carboxylic acid group in the side chain, such as JP 59-44615, JP-B 54-34327, JP-B 58-12777, and JP-B. 54-25957, JP-A-54-92723, JP-A-59-53836, JP-A-59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer , Itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer, and partially esterified maleic acid copolymer. Similarly, there is an acidic cellulose derivative having a carboxylic acid group in the side chain. In addition, those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxyl group are useful.

Among these, [benzyl (meth) acrylate / (meth) acrylic acid / other addition polymerizable vinyl monomers as required] copolymer and [allyl (meth) acrylate / (meth) acrylic acid / as required Other addition-polymerizable vinyl monomers] are preferred because they are excellent in the balance of film strength, sensitivity and developability.
In addition, Japanese Patent Publication No. 7-2004, Japanese Patent Publication No. 7-120041, Japanese Patent Publication No. 7-120042, Japanese Patent Publication No. 8-12424, Japanese Patent Laid-Open No. 63-287944, Japanese Patent Laid-Open No. 63-287947, Japanese Patent Laid-Open No. The urethane-based binder polymer containing an acid group described in each publication of Japanese Patent No. 271741 and Japanese Patent Application No. 10-116232 is very excellent in strength, and is advantageous in terms of printing durability and suitability for low exposure. It is.
A binder having an amide group described in JP-A No. 11-171907 is suitable because it has excellent developability and film strength.

  In addition, polyvinyl pyrrolidone, polyethylene oxide, and the like are useful as the water-soluble linear organic polymer. In order to increase the strength of the cured film, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, and the like are also useful. These linear organic high molecular polymers can be mixed in an arbitrary amount in the entire composition. However, when it exceeds 90% by mass, a preferable result is not given in terms of the strength of the formed image. Preferably it is 30-85 mass%. The photopolymerizable compound having an ethylenically unsaturated double bond and the linear organic polymer are preferably in the range of 1/9 to 7/3 by mass ratio. In a preferred embodiment, a binder polymer that does not require water and is soluble in alkali is used. By doing so, an organic solvent that is not environmentally preferable is not used as the developer, or the amount can be limited to a very small amount. In such a method of use, the acid value of the binder polymer (the acid content per gram of polymer expressed as a chemical equivalent number) and the molecular weight are appropriately selected from the viewpoint of image strength and developability. The preferred acid value is 0.4 to 3.0 meq / g, and the preferred molecular weight is in the range of 3000 to 500,000 in terms of mass average molecular weight, more preferably the acid value is 0.6 to 2.0 and the molecular weight is It is in the range of 10,000 to 300,000.

(E) Other components The photosensitive composition of the present invention may further contain other components suitable for its use and production method. Hereinafter, preferred additives will be exemplified.

(E-1) Co-sensitizer The sensitivity can be further improved by using a certain additive (hereinafter referred to as a co-sensitizer). These mechanisms of action are not clear, but many are thought to be based on the following chemical processes. That is, the photosensitivity initiated by the thermal polymerization initiator and the various intermediate active species (radicals and cations) generated during the subsequent addition polymerization reaction react with the co-sensitizer to generate new active radicals. It is estimated that These can be broadly divided into (a) those that can be reduced to generate active radicals, (b) those that can be oxidized to generate active radicals, and (c) radicals that are more active by reacting with less active radicals. Can be classified into those that act as chain transfer agents, but there is often no generality as to which of these individual compounds belong.

(A) Compound that is reduced to produce an active radical Compound having a carbon-halogen bond: It is considered that the carbon-halogen bond is reductively cleaved to generate an active radical. Specifically, for example, trihalomethyl-s-triazines and trihalomethyloxadiazoles can be preferably used.
Compound having nitrogen-nitrogen bond: It is considered that the nitrogen-nitrogen bond is reductively cleaved to generate an active radical. Specifically, hexaarylbiimidazoles and the like are preferably used.
Compound having oxygen-oxygen bond: It is considered that an oxygen-oxygen bond is reductively cleaved to generate an active radical. Specifically, for example, organic peroxides are preferably used.
Onium compounds: It is considered that carbon-hetero bonds and oxygen-nitrogen bonds are reductively cleaved to generate active radicals. Specifically, for example, diaryliodonium salts, triarylsulfonium salts, N-alkoxypyridinium (azinium) salts and the like are preferably used.
Ferrocene and iron arene complexes: An active radical can be reductively generated.

(B) Compound which is oxidized to generate an active radical Alkylate complex: It is considered that a carbon-hetero bond is oxidatively cleaved to generate an active radical. Specifically, for example, triarylalkyl borates are preferably used.
Alkylamine compound: It is considered that the C—X bond on carbon adjacent to nitrogen is cleaved by oxidation to generate an active radical. X is preferably a hydrogen atom, a carboxyl group, a trimethylsilyl group, a benzyl group or the like. Specific examples include ethanolamines, N-phenylglycines, N-trimethylsilylmethylanilines and the like.
Sulfur-containing and tin-containing compounds: Compounds in which the nitrogen atoms of the above-described amines are replaced with sulfur atoms and tin atoms can generate active radicals by the same action. Further, a compound having an SS bond is also known to be sensitized by SS cleavage.

α-Substituted methylcarbonyl compound: An active radical can be generated by oxidative cleavage of the carbonyl-α carbon bond. Moreover, what converted carbonyl into the oxime ether also shows the same effect | action. Specifically, 2-alkyl-1- [4- (alkylthio) phenyl] -2-morpholinopronone-1 and these and a hydroxylamine were reacted, and then N—OH was etherified. Oxime ethers can be listed.
Sulfinic acid salts: An active radical can be reductively generated. Specific examples include arylsulfin sodium.

(C) Compounds that react with radicals to convert to highly active radicals or act as chain transfer agents: For example, compounds having SH, PH, SiH, GeH in the molecule are used. These can generate hydrogen by donating hydrogen to a low-activity radical species to generate radicals, or after being oxidized and deprotonated. Specific examples include 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 2-mercaptobenzimidazoles and the like.

  More specific examples of these co-sensitizers are described, for example, in JP-A-9-236913 as additives for the purpose of improving sensitivity, and these are also applied in the present invention. be able to. Some examples are shown below, but the present invention is not limited thereto. In the following formulae, -TMS represents a trimethylsilyl group.

These co-sensitizers can also be subjected to various chemical modifications for improving the characteristics of the photosensitive layer as in the case of the above sensitizing dyes. For example, bonds with sensitizing dyes, initiator compounds, addition polymerizable unsaturated compounds and other parts, introduction of hydrophilic sites, compatibility improvement, introduction of substituents for suppressing crystal precipitation, substituents for improving adhesion Methods such as introduction and polymerization can be used.
These co-sensitizers can be used alone or in combination of two or more. The amount used is 0.05 to 100 parts by weight, preferably 1 to 80 parts by weight, and more preferably 3 to 50 parts by weight with respect to 100 parts by weight of the compound having an ethylenically unsaturated double bond.

(E-2) Polymerization inhibitor In the present invention, in addition to the above basic components, unnecessary thermal polymerization of a compound having an ethylenically unsaturated double bond that can be polymerized during production or storage of the photosensitive composition. In order to prevent this, it is desirable to add a small amount of a thermal polymerization inhibitor. 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 entire composition. In addition, if necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to prevent polymerization inhibition due to oxygen, and a lithographic printing plate precursor is dried after coating on a support or the like. In this process, it may be unevenly distributed on the surface of the photosensitive layer. The amount of the higher fatty acid derivative added is preferably about 0.5% by mass to about 10% by mass of the total composition.

(E-3) Colorant, etc. Furthermore, when the photosensitive composition of the present invention is used for a lithographic printing plate precursor, a dye or pigment may be added for the purpose of coloring the photosensitive layer. Thereby, the so-called plate inspection properties such as the visibility after plate making and the suitability of an image density measuring machine as a printing plate can be improved. Since many dyes cause a reduction in sensitivity of the photosensitive layer, 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 is preferably about 0.5% by mass to about 5% by mass of the total composition.

(E-4) Other additives Further, when the photosensitive composition of the present invention is used for a lithographic printing plate precursor, an inorganic filler, other plasticizers, and ink on the surface of the photosensitive layer are used to improve the physical properties of the cured film. You may add well-known additives, such as a fat-sensitizing agent which can improve the inking property.

  Examples of plasticizers include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, and triacetyl glycerin. 10 mass% or less can be added with respect to the total mass of the compound which has an ionic unsaturated double bond, and a binder.

Further, for the purpose of improving the film strength (printing durability) described later, a UV initiator, a mature crosslinking agent, or the like can be added to enhance the effect of heating and exposure after development.
In addition, it is also possible to provide an additive and an intermediate layer for improving the adhesion between the photosensitive layer and the support and improving the development and removal of the unexposed photosensitive layer. For example, by adding or undercoating a compound having a relatively strong interaction with the substrate, such as a compound having a diazonium structure or a phosphone compound, adhesion can be improved and printing durability can be improved. By adding or undercoating a hydrophilic polymer such as acid or polysulfonic acid, the developability of the non-image area is improved, and the stain resistance can be improved.

  In order to produce a lithographic printing plate precursor, when the photosensitive composition of the present invention is applied on a support to form a photosensitive layer, it is dissolved in various organic solvents and used. 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 are ethyl and the like. These solvents can be used alone or in combination. The solid content in the coating solution is suitably 2 to 50% by mass.

The coating amount of the photosensitive layer on the support is preferably selected as appropriate according to the use in consideration of the sensitivity of the photosensitive layer, the developability, the strength of the exposed film and the printing durability. 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. The coating amount as the photosensitive layer of the lithographic printing plate precursor for scanning exposure, which is a preferred use mode of the photosensitive composition of the present invention, is generally about 0.1 g / m ² to about 10 g / m in terms of the mass after drying. A range of m ² is suitable. More preferably from 0.5 to 5 g / m ^2.

  In addition, when using the photosensitive composition of the present invention as a photosensitive layer of a lithographic printing plate precursor, from the viewpoint of sensitivity and storage stability, a compound represented by the general formula (I) is used as a sensitizing dye. An initiator system in which a titanocene compound or a hexaarylbiimidazole compound is combined as an agent compound is preferable, an initiator system in which a hexaarylbiimidazole compound is combined is more preferable, and an initiator system comprising these and (C-1) an addition polymerizable compound The containing aspect is particularly preferred.

(Support)
In order to obtain a lithographic printing plate precursor using the photosensitive composition of the present invention, it is desirable to provide the photosensitive layer on a support having a hydrophilic surface. As the hydrophilic support, a conventionally known hydrophilic support used in a lithographic printing plate 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.) It is done. These may be a single component sheet such as a resin film or a metal plate, or may be a laminate of two or more materials. For example, a paper or plastic film on which a metal as described above is laminated or vapor-deposited. And laminated sheets of different plastic films. Also, these surfaces may be subjected to appropriate known physical and chemical treatments for the purpose of imparting hydrophilicity and improving strength, if necessary.

  Particularly preferred supports include paper, polyester film or aluminum plate, among which dimensional stability is good and relatively inexpensive, and a surface with excellent hydrophilicity and strength can be provided by surface treatment as required. An aluminum plate is particularly preferred. 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.

  A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements. Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, particularly preferably 0.2 mm to 0.3 mm.

In the case of a support having a surface of metal, particularly aluminum, roughening (graining) treatment, immersion treatment in an aqueous solution of sodium silicate, potassium fluoride zirconate, phosphate, etc., or anodic oxidation treatment, etc. It is preferable that surface treatment is performed.
Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired.
The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.
The aluminum plate roughened in this way can be subjected to an anodizing treatment to enhance the water retention and wear resistance of the surface through an alkali etching treatment and a neutralization treatment, if desired. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

Furthermore, an aluminum plate that has been roughened and then immersed in an aqueous sodium silicate solution can be preferably used. As described in Japanese Patent Publication No. 47-5125, an aluminum plate is anodized and then immersed in an aqueous solution of an alkali metal silicate is preferably used. The anodizing treatment is carried out in an electrolytic solution in which an inorganic acid such as phosphoric acid, chromic acid, sulfuric acid or boric acid, or an organic acid such as oxalic acid or sulfamic acid, or a salt solution thereof, or a combination of two or more thereof, is used. This is carried out by passing an electric current using the aluminum plate as an anode.
Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective as a hydrophilic treatment for the support. A support body provided with electrolytic grains as disclosed in JP-B-46-27481, JP-A-52-58602, and JP-A-52-30503, and the above-described anodizing treatment and sodium silicate treatment. A combined surface treatment is also useful. Further, those obtained by sequentially performing mechanical surface roughening, chemical etching, electrolytic graining, anodizing treatment and sodium silicate treatment as disclosed in JP-A-56-28893 are also suitable.

Furthermore, after performing these treatments, water-soluble resins such as polyvinylphosphonic acid, polymers and copolymers having sulfonic acid groups in the side chain, polyacrylic acid, water-soluble metal salts (for example, zinc borate) or Those having a primer such as a yellow dye or an amine salt are also suitable.
Further, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A-7-159983 is covalently used.
As another preferred example, a substrate provided with a water-resistant hydrophilic layer as a surface layer on an arbitrary support can be raised. Examples of such a surface layer include a layer composed of an inorganic pigment and a binder described in US Pat. No. 3,055,295 and JP-A-56-13168, and a hydrophilic swelling described in JP-A-9-80744. Examples thereof include sol-gel films made of titanium oxide, polyvinyl alcohol, and silicic acids described in JP-A-8-507727.
These hydrophilic treatments are performed to make the surface of the support hydrophilic, in order to prevent harmful reactions of the photosensitive composition provided thereon, and to improve the adhesion of the photosensitive layer, etc. It is for the purpose.

(Protective layer)
When the photosensitive composition of the present invention is used in a lithographic printing plate precursor for scanning exposure, a protective layer can be provided on the photosensitive layer containing a polymerizable compound as necessary. Such a lithographic printing plate precursor is usually exposed in the air, but the protective layer is a low molecular weight molecule such as oxygen or a basic substance present in the air that inhibits the image forming reaction caused by exposure in the photosensitive layer. This prevents the compound from being mixed into the photosensitive layer, and prevents the inhibition of the image forming reaction due to exposure in the air. Therefore, the properties desired for such a protective layer are low permeability of low-molecular compounds such as oxygen, furthermore, good transparency of light used for exposure, excellent adhesion to the photosensitive layer, And it is desirable that it can be easily removed in the development process after exposure.

Such a device for the protective layer has been conventionally devised, and is described in detail in US Pat. No. 3,458,311 and JP-A-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, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, Water-soluble polymers such as acrylic acid are known, but among these, using polyvinyl alcohol as a 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. In particular, a mixture obtained by replacing polyvinyl pyrrolidone in a range of 15 to 50% by mass with respect to polyvinyl alcohol is preferable from the viewpoint of storage stability.

  Specific examples of polyvinyl alcohol include those having a hydrolysis rate of 71 to 100% and a molecular weight in the range of 300 to 2400. Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, manufactured by Kuraray Co., Ltd. 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 the unsubstituted vinyl alcohol unit in the protective layer), the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. 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. In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on 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, 20 to 60% by mass of acrylic emulsion or water-insoluble vinylpyrrolidone-vinyl acetate copolymer is mixed in a hydrophilic polymer made of polyvinyl alcohol and laminated on the photosensitive layer, thereby providing sufficient adhesion. It is described that it is obtained. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method for the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and JP-A-55-49729.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (such as a water-soluble dye) that is excellent in transparency of light used for exposure (for example, a wavelength of 760 to 1200 nm for an infrared laser) and can efficiently absorb light of a wavelength that is not related to exposure. Therefore, the suitability for safelight can be further enhanced without lowering the sensitivity.

When a lithographic printing plate precursor using the photosensitive composition of the present invention is made into a lithographic printing plate, it is usually subjected to an exposure process (image exposure) described in detail below, and then a photosensitive layer with a developer. The unexposed portion is removed to form an image. As a preferred developing solution when these photosensitive compositions are used for preparing a lithographic printing plate, a developing solution described in JP-B-57-7427 is exemplified, and sodium silicate and potassium silicate are used. , Sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia etc. An inorganic alkaline agent and an aqueous solution of an organic alkaline agent such as monoethanolamine or diethanolamine are suitable. Such an alkaline agent is added so that the concentration of the alkaline solution is 0.1 to 10% by mass, preferably 0.5 to 5% by mass.

Such an alkaline aqueous solution may contain a small amount of a surfactant, an organic solvent such as benzyl alcohol, 2-phenoxyethanol, and 2-butoxyethanol as necessary. Examples thereof include those described in US Pat. Nos. 3,375,171 and 3,615,480.
Further, the developers described in JP-A-50-26601, 58-54341, JP-B-56-39464, and 56-42860 are also excellent.

  As a particularly preferred developer used here, a nonionic compound described in JP-A No. 2002-202616 is contained, the pH is 11.5 to 12.8, and the conductivity is 3 to 30 mS / cm. And a developer having

  In the plate-making process of the lithographic printing plate precursor according to the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. By such heating, the image forming reaction in the photosensitive layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. Further, for the purpose of improving the image strength and printing durability, it is also effective to subject the developed image to full post heating or full exposure. Usually, heating before development is preferably performed under mild conditions of 150 ° C. or lower. If the temperature is too high, problems such as an undesired curing reaction in the non-image area may occur. On the other hand, very strong conditions can be used for heating after development. Usually, a heat treatment in the range of 200 to 500 ° C. is performed. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

  As a method for exposing the lithographic printing plate precursor for scanning exposure according to the present invention, a known method can be used without limitation. Desirably, the wavelength of the light source is 350 nm to 450 nm, and specifically, an InGaN-based semiconductor laser is suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like. In addition, the photosensitive layer component of the present invention can be made soluble in neutral water or weak alkaline water by using a highly water-soluble component. After loading on top, a system such as exposure-development can be performed on the machine.

As an available laser light source of 350 to 450 nm, the following can be used.
As a gas laser, an Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), a Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), a He—Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and a solid state laser as Nd: YAG (YVO ₄ ) and SHG crystal × 2 combinations (355 nm, 5 mW to 1 W), Cr: LiSAF and SHG crystal combination (430 nm, 10 mW), as a semiconductor laser system, KNbO ₃ ring resonator (430 nm, 30 mW), Combination of waveguide wavelength conversion element and AlGaAs, InGaAs semiconductor (380 nm to 450 nm, 5 mW to 100 mW), combination of waveguide wavelength conversion element, AlGaInP, and AlGaAs semiconductor (300 nm to 350 nm, 5 mW to 100 mW), A GaInN (350nm~450nm, 5mW~30mW) Other, N2 laser as a pulse laser (337nm, pulse 0.1~10mJ), XeF (351nm, pulse 10~250mJ), etc. can be used.
Among these, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 400 to 410 nm, 5 to 30 mW) is preferable in terms of wavelength characteristics and cost.

Further, as the lithographic printing plate exposure apparatus of the scanning exposure method, there are an inner drum method, an outer drum method, and a flat bed method as an exposure mechanism, and all of the light sources other than the pulse laser can be used as a light source. . Practically, the following exposure apparatus is particularly preferable in terms of the relationship between the photosensitive material sensitivity and the plate making time.
・ Single beam exposure system that uses one gas laser or solid-state laser light source with internal drum system ・ Multi-beam exposure system that uses many (10 or more) semiconductor lasers with flat bed system ・ Many semiconductor lasers with external drum system ( Multi-beam exposure equipment used (10 or more)

In the laser direct-drawing lithographic printing plate as described above, the photosensitive material sensitivity X (J / cm ² ), the photosensitive material exposure area S (cm ² ), the power q (W) of one laser light source, the laser Equation (eq1) is established between the number n and the total exposure time t (s).
X · S = n · q · t (eq1)

i) In the case of an internal drum (single beam) system, the laser rotation speed f (radians / s), the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dots / cm), and the total exposure time t (s) In general, equation (eq2) holds.
f · Z · t = Lx (eq2)

ii) External drum (multi-beam) system Drum rotation speed F (radians / s), photosensitive material sub-scanning length Lx (cm), resolution Z (dots / cm), total exposure time t (s), number of beams In general, equation (eq3) is established during (n).
F.Z.n.t = Lx (eq3)

iii) In the case of a flat bed (multi-beam) system, the rotational speed H of the polygon mirror (radians / s), the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dots / cm), the total exposure time t (s), Equation (eq4) is generally established between the number of beams (n).
H.Z.n.t = Lx (eq4)

Resolution required for an actual printing plate (2560 dpi), plate size (A1 / B1, sub-scan length 42 inch), exposure conditions of about 20 sheets / hour and photosensitive characteristics of the photosensitive composition of the present invention (photosensitive wavelength, By substituting (sensitivity: about 0.1 mJ / cm ² ) into the above equation, it can be understood that a combination with a semiconductor laser multi-beam exposure method is more preferable in the light-sensitive material of the present invention. Further, by combining operability, cost, etc., a combination with an external drum type semiconductor laser multi-beam exposure apparatus is most preferable.

  In addition, as other exposure light rays for the photosensitive composition of the present invention, ultrahigh pressure, high pressure, medium pressure, and low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, various visible and ultraviolet laser lamps Fluorescent lamps, tungsten lamps, sunlight, etc. can also be used.

Applications of the photosensitive composition according to the present invention can be applied without limitation to a wide range of fields known as applications of photocurable resins, in addition to the photosensitive layer of the lithographic printing plate precursor for scanning exposure described in detail above. For example, a highly sensitive optical modeling material can be obtained by applying to a liquid photosensitive composition used in combination with a cationically polymerizable compound as necessary. Further, a hologram material can be obtained by utilizing a change in refractive index accompanying photopolymerization. It can be applied to various transfer materials (peeling sensitive material, toner developing sensitive material, etc.) by utilizing the change in surface adhesiveness accompanying photopolymerization. It can also be applied to photocuring of microcapsules. It can also be applied to the production of electronic materials such as photoresists, and photocurable resin materials such as inks, paints, and adhesives.

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

<Examples 1-17, Comparative Examples 1-5>
(Preparation of support)
An aluminum plate having a thickness of 0.3 mm was etched by being immersed in 10% by mass sodium hydroxide at 60 ° C. for 25 seconds, washed with running water, neutralized with 20% by mass nitric acid, and then washed with water. This was subjected to an electrolytic surface roughening treatment in a 1% by mass nitric acid aqueous solution using a sinusoidal alternating waveform current at an anode time electricity of 300 coulomb / dm ² . Subsequently, after dipping in a 1% by mass aqueous sodium hydroxide solution at 40 ° C. for 5 seconds and then in a 30% by mass sulfuric acid aqueous solution and desmutting at 60 ° C. for 40 seconds, the current density in a 20% by mass sulfuric acid aqueous solution was 2A / current density. At dm ² , the anodization treatment was performed for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² . When the surface roughness was measured, it was 0.3 μm (Ra indication according to JISB0601).

The following back coat coating solution was applied to the back surface of the substrate thus treated with a bar coater, dried at 100 ° C. for 1 minute, and a support provided with a back coat layer having a coating amount of 70 mg / m ² after drying. Produced. The backcoat coating solution was prepared from the following sol-gel reaction solution and the following additive solution as follows.

(Sol-gel reaction solution)
Tetraethylsilicate 50 parts by weight Water 20 parts by weight Methanol 15 parts by weight Phosphoric acid 0.05 parts by weight

  When the above components were mixed and stirred, heat generation started in about 5 minutes. After reacting for 60 minutes, a backcoat coating solution was prepared by adding the following additive solution.

(Additive solution)
Pyrogallol formaldehyde condensation resin (molecular weight 2000) 4 parts by weight Dimethyl phthalate 5 parts by weight Fluorosurfactant 0.7 parts by weight (N-butylperfluorooctane / sulfonamidoethyl acrylate / polyoxyethylene acrylate copolymer: molecular weight 20,000)
Methanol silica sol 50 parts by mass (manufactured by Nissan Chemical Industries, Ltd., methanol 30% by mass)
800 parts by mass of methanol

(Formation of photosensitive layer)
On the aluminum plate thus treated, a photopolymerizable composition having the following composition was applied so that the dry coating amount was 1.0 g / m ² . Next, it was dried at 80 ° C. for 2 minutes to form a photosensitive layer.

(Photopolymerizable composition)
・ The above polymerizable compound 1.54 g
・ Binder polymer Allyl methacrylate / Methacrylic acid /
N-isopropylacrylamide copolymer 2.1 g
(Copolymerization molar ratio 67/13/20)
-Photopolymerization initiation system (described in Table 1)
Sensitizing dye Xg
Initiator compound Yg
Co-sensitizer Zg
・ Other components Fluorine-based nonionic surfactant (F-177P) 0.015 g
Thermal polymerization inhibitor N-nitrosophenyl hydroxyl 0.02 g
Amine aluminum salt Pigment dispersion 1.9 g
Composition of pigment dispersion Composition: Pigment Blue 15: 6 15 parts by mass
Allyl methacrylate / methacrylic acid copolymer 15 parts by mass
(Copolymerization molar ratio 83/17)
15 parts by mass of cyclohexanone
22 parts by mass of methoxypropyl acetate
40 parts by mass of propylene glycol monomethyl ether / solvent methyl ethyl ketone 20.0 g
Propylene glycol monomethyl ether 20.0 g

(Formation of protective layer)
On this photosensitive layer, a 3% by weight aqueous solution of polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 550) was applied so that the dry coating weight was 2 g / m ^2, and dried at 100 ° C. for 2 minutes for protection. A layer was formed to obtain a lithographic printing plate precursor.

[Sensitivity evaluation]
On the lithographic printing plate precursor thus obtained, Fuji Photo Film Co., Ltd. Fuji step guide (gray scale whose transmission optical density changes discontinuously at ΔD = 0.15) is adhered, Exposure was performed with a xenon lamp through an optical filter so as to obtain a known exposure energy.
Thereafter, the film was immersed in a developer having the following composition at 25 ° C. for 10 seconds, developed, the maximum number of steps at which the image was completely removed was read, the exposure energy amount was determined, and the sensitivity (clear sensitivity) was calculated (unit) MJ / cm ² ). The smaller the amount of energy, the higher the sensitivity. For the purpose of estimating the suitability for exposure to a short-wave semiconductor laser, Kenko BP-40 was used as an optical filter, and exposure was performed with 400 nm monochromic light. The results are shown in Table 1.

(Developer)
PH 12.0 aqueous solution having the following composition: Potassium hydroxide 0.2 g
1K potassium silicate 2.4g
(SiO ₂ / K ₂ O = 1.9)
Compound of the following formula (1) 5.0 g
Ethylenediaminetetraacetic acid, 4Na salt 0.1g
91.3g of water

(Developability evaluation)
(Practical performance)
After the steps up to the development step in the sensitivity evaluation were repeated for 100 m ² minutes, the precipitation of the dye component on the automatic developing machine was visually evaluated. Apparent precipitation was marked with x, a level that was difficult to judge was marked with △, and no precipitation was marked with ◯.

(Compound solubility)
The solubility in the present invention is measured as follows.
Dissolve a specific amount of sensitizing dye in 2 ml of MEK, and then add 98 ml of a 25 ° C. developer (water solution obtained by diluting Fuji Photo Film DV-2 5 times with water) adjusted to pH = 11.95. did. After further stirring for 1 hour, the mixture was filtered using a microfilter. This filtrate was further diluted 5-fold, and then UV measurement was performed by a conventional method. After the amount of dissolution was calculated from the absorption intensity, it was converted into the amount dissolved per liter of developer.

(Evaluation of storage stability)
The lithographic printing plate produced with the configuration described in the Examples was evaluated for storage stability by comparing the clear sensitivity with the sensitivity after aging under forced conditions under the following two conditions.
(I) Immediately after coating, exposure and development (ii) Storage under forced storage conditions at 60 ° C. for 10 days, exposure and development The clear sensitivity here is the same as described above. The difference ((ii) / (i)) between the sensitivity of (i) and the sensitivity of (ii) was defined as the clear sensitivity ratio. The closer this value is to 1, the smaller the change in image forming sensitivity between the time-sensitive material and the time-sensitive material, and it can be said that the storage stability is high.

  In Table 1, the structure of the sensitizing dye according to the present invention used in the photopolymerization initiation system is the same as that of the exemplified compound. In addition, the structures of the initiator compounds (T-1) to (T-3) and the co-sensitizer (R-1) are as shown below. The following sensitizing dyes (H-1) to (H-3) used in Comparative Examples are dye compounds outside the scope of the present invention.

As is clear from Table 1, it was found that any of the lithographic printing plate precursors using the photosensitive composition of the present invention for the photosensitive layer did not greatly reduce the sensitivity and could suppress dye deposition in the developing machine.
Specifically, the sensitizing dye having a solubility in a developer of 400 mg / l or more in Examples 1 to 7 has a structure in which a hydrophilic group is added to the structure of the sensitizing dye in Comparative Examples 1 and 2. However, it was found that by having a hydrophilic group, a photosensitive composition using the same exhibits high sensitivity while suppressing dye deposition. At this time, the carbon number of the alkyl group in the amino group on the aryl group was 3, and D-19 using an acetyl group as the hydrophilic group showed the highest sensitivity. The reason for this is as described above. However, it was confirmed that high sensitivity can be maintained while imparting solubility of the sensitizing dye to the developer by providing the hydrophilic group in this way.
In addition, the photosensitive compositions of Examples 8 to 13 have an ester or the like as the hydrophilic group of the sensitizing dye. These are less soluble than hydroxyl groups and the like, but can impart a solubility of 100 (mg / l) or more, thereby using a sensitizing dye having a solubility of less than 100 (mg / l). It turned out that pigment precipitation can be suppressed rather than (Comparative Examples 1-5).
Furthermore, by comparing Comparative Examples 4 and 5 with Examples 14 to 17, it was found that the same properties (sensitivity and developability) were exhibited even in systems using various initiators.
Regarding storage stability, good results were obtained in any structure. It is believed that this is because the dye itself is highly stable and the compound is less likely to change over time.

Claims (3)

(A) a sensitizing dye having a solubility in an alkali developer at 25 ° C. (pH = 11.95) of 100 (mg / l) or more,
(B) an initiator compound capable of generating a radical, an acid or a base, and (C) a polymerizable compound which reacts with at least one of a radical, an acid or a base,
Containing the photosensitive composition. (A) A sensitizing dye represented by the following general formula (I) and having a solubility in an alkaline developer at 25 ° C. (pH = 11.95) of 100 (mg / l) or more,
(B) an initiator compound capable of generating a radical, an acid or a base, and (C) a polymerizable compound which reacts with at least one of a radical, an acid or a base,
Containing the photosensitive composition.

(In the general formula (I), A represents an aromatic ring or a hetero ring which may have a substituent, R ₁ represents a hydrogen atom or a monovalent nonmetallic atomic group. A and R ₁ are each They can be bonded to each other to form an aliphatic or aromatic ring, and Z represents a 5-membered or 6-membered ring structure containing a hetero atom.
The sensitizing dye represented by the general formula (I) has at least one COOR ₂ group, SO ₃ R ₃ group, PO at a site selected from a substituent on A, Z, R ₁ or R _{1. It} has a substituent selected from ₃ R ₄ group, OH group, and OCOR ₅ group. R ₂ , R ₃ , R ₄ , and R ₅ each independently represent a monovalent nonmetallic atomic group that is not a hydrogen atom. )   An image recording material comprising a photosensitive layer containing the photosensitive composition according to claim 1 on a support.