JP4538351B2 - Photosensitive composition - Google Patents

Description

  The present invention is a photosensitive composition 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. And an image recording method using the same. In particular, the present invention relates to a photosensitive composition that can be directly made by using various lasers from a digital signal of a computer or the like, that is preferably used as a lithographic printing plate material capable of direct plate making, and an image recording method using the same.

  Solid-state lasers, semiconductor lasers, and gas lasers that emit ultraviolet light, visible light, and infrared light having a wavelength of 300 nm to 1200 nm are easily available as high-power and small-sized lasers. It is very useful as a recording light source when making a plate directly from data. Various researches have been made on recording materials that are sensitive to these various laser beams. As typical examples, as materials that can be recorded with an infrared laser having a photosensitive wavelength of 760 nm or more, a positive recording material described in Patent Document 1 is used. In addition, there are acid-catalyst-crosslinked negative recording materials described in Patent Document 2, and the recording materials for 300 nm to 700 nm ultraviolet light or visible light laser are described in Patent Document 3 and Patent Document 4. There are many known radical polymerization type negative recording materials.

  The problem common to all these image forming materials is how to enlarge the ON / OFF of the image in the above-mentioned various energy irradiated portions and unexposed portions, that is, the high sensitivity and storage stability of the image forming materials. It is compatible. Usually, the radical photopolymerization system is highly sensitive, but the sensitivity is greatly lowered due to polymerization inhibition by oxygen in the air. Therefore, means for providing an oxygen barrier layer on the image forming layer is taken. However, when an oxygen-blocking layer is provided, fogging due to dark polymerization or the like occurs, and storage stability deteriorates. Accordingly, it is difficult to achieve both high sensitivity and storage stability. The conventional technique has not obtained a satisfactory result, and a new technique that has not been conventionally required has been demanded.

On the other hand, high-sensitivity photoinitiators are described in Non-Patent Document 1 and Non-Patent Document 2, and are known.
However, even the photosensitive composition using the high-sensitivity photoinitiator according to these proposals has not yet obtained a sufficiently satisfactory effect when used as required for an image forming material. Development of a photosensitive composition having a photopolymerization initiation system that satisfies the performance required for a photosensitive layer is desired.
U.S. Pat. No. 4,708,925 JP-A-8-276558 U.S. Pat. No. 2,850,445 Japanese Patent Publication No. 44-20189 Bruce M. By Monroe et al., Chemical Rev. , 93, 435 (1993) R. S. By Davidson et al., Journal of Photochemistry and biology, 73, 81 (1993).

Accordingly, an object of the present invention is to provide a highly sensitive photosensitive composition that is excellent in sensitivity, workability, and economy and can be used as an image recording material for scanning exposure that is compatible with a CTP system. An object of the present invention is to provide a photosensitive composition used as an image recording material having high sensitivity to the oscillation wavelength of a short-wave semiconductor laser. In particular, a photosensitive composition suitable as a plate material for lithographic printing that can be directly made from digital data such as a computer by recording using solid-state laser and semiconductor laser light emitting ultraviolet light, visible light and infrared light. It is to provide. Another object of the present invention is to provide a photosensitive composition that uses a novel photopolymerization initiation system that is highly sensitive to a wide wavelength range from 350 nm to 850 nm and has high workability.

As a result of intensive studies to achieve the above object, the present inventors have obtained extremely excellent sensitivity when a sensitizing dye having a specific structure having at least two polymerizable groups and an initiator compound are combined. It has been found that a photopolymerization initiation system can be obtained, and a photopolymerization initiation system suitable for exposure at 350 nm to 850 nm, particularly 350 nm to 450 nm can be obtained.
Furthermore, a photosensitive composition comprising this photopolymerization initiation system and a polymerizable compound that reacts with radicals or acids, specifically an addition polymerizable compound having an ethylenically unsaturated double bond, is used for an image recording material. In this case, the inventors have found that a lithographic printing plate precursor having sufficient sensitivity to the oscillation wavelength of a short-wave semiconductor laser and having high economy can be obtained, and the present invention has been achieved.

  That is, the present invention is as follows.

（一般式（Ｉ）中、Ｒ₁、Ｒ₂は、それぞれ独立に１価の有機基を表し、Ａｒ₁、Ａｒ₂は、それぞれ独立に、置換基を有していてもよい芳香族基、又はヘテロ環基を表し、Ｙ₁、Ｙ₂は、それぞれ独立に、硫黄原子、酸素原子、セレン原子、炭素原子数１２個以下のジアルキルメチレン基、又は−ＣＨ＝ＣＨ−基を表し、Ｍ⁻は、アニオンを表す。ｎは、１または２を表す。Ａｒ₃、Ａｒ₄は、それぞれ独立に、置換基を有してもよい芳香族基、又はヘテロ環基を表す。なお、Ｒ₁、Ｒ₂、Ａｒ₁、Ａｒ₂、Ａｒ₃、及びＡｒ₄の少なくとも２つが、ラジカルによって反応する重合性基を含む置換基であることを要する。）

（一般式（ＩＩ）中、Ｘ₁は酸素原子、硫黄原子、−ＣＲ’Ｒ’’又は−ＮＲ’’’−を表す。Ｘ₂は酸素原子、硫黄原子、＝ＣＲ’Ｒ又は＝ＮＲ’’を表す。またＲ’とＲはそれぞれ独立に水素原子又は一価の非金属原子団を表し、またそれぞれ互いに結合して、脂肪族性または芳香族性の環を形成することができ、さらにその環状部の置換基としてラジカルによって反応する重合性基を含む置換基を持ってもよい。Ｒ₃、Ｒ₄、Ｒ₅、Ｒ₆、Ｒ’〜Ｒ’’’はそれぞれ独立に水素原子又は一価の非金属原子団を表し、またそれぞれ互いに結合して、脂肪族性または芳香族性の環を形成することができる。なお、Ｒ₃、Ｒ₄、Ｒ₅、Ｒ₆、Ｒ’〜Ｒ’’’は少なくとも２つがラジカルによって反応する重合性基を含む置換基であることを要する。）

（一般式（III）中、Ｒ₇〜Ｒ₁₆はそれぞれ独立に水素原子又は一価の非金属原子団を表し、またそれぞれ互いに結合して、脂肪族性または芳香族性の環を形成することができる。なお、Ｒ₇〜Ｒ₁₆は少なくとも２つがラジカルによって反応する重合性基を含む置換基であることを要する。）

（前記一般式（ＩＶ）中、Ｒ₁₇〜Ｒ₁₉はそれぞれ独立に水素原子又は一価の非金属原子団を表し、またそれぞれ互いに結合して、脂肪族性または芳香族性の環を形成することができる。Ｚは隣接する原子と共同して、酸性核を形成するのに必要な２価の非金属原子団を表す。なお、Ｒ₁₇〜Ｒ₁₉は少なくとも２つがラジカルによって反応する重合性基を含む置換基であることを要する。） 1. (A) a sensitizing dye having an absorption maximum λ _max at 350 nm to 850 nm and having at least two polymerizable groups that react with radicals;
(B) an initiator compound capable of generating radicals, and (C) a polymerizable compound that reacts with radicals, and (A) a sensitizing dye is represented by the following general formulas (I) to (IV): A photosensitive composition characterized by being at least one of the following.

(In general formula (I), R ₁ and R ₂ each independently represents a monovalent organic group, and Ar ₁ and Ar ₂ each independently represent an aromatic group optionally having a substituent, or a heterocyclic group, Y _1, Y ₂ each independently represent a sulfur atom, an oxygen atom, a selenium atom, a carbon atom number of 12 or less dialkyl methylene group, or -CH = CH- group, M ^- Represents an anion, n represents 1 or 2. Ar ₃ and Ar ₄ each independently represents an aromatic group or a heterocyclic group which may have a substituent, wherein R ₁ , (At least two of R ₂ , Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ must be substituents containing a polymerizable group that reacts with a radical.)

(In the general formula (II), X ₁ represents an oxygen atom, a sulfur atom, —CR′R ″ or —NR ′ ″ —. X ₂ represents an oxygen atom, a sulfur atom, ═CR′R or ═NR ′. R 'and R each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and can be bonded to each other to form an aliphatic or aromatic ring; It may have a substituent containing a polymerizable group that reacts with a radical as a substituent of the cyclic part.R ₃ , R ₄ , R ₅ , R ₆ , R ′ to R ′ ″ are each independently a hydrogen atom or Represents a monovalent non-metallic atomic group, and can be bonded to each other to form an aliphatic or aromatic ring, wherein R ₃ , R ₄ , R ₅ , R ₆ , R′˜ R ′ ″ is required to be a substituent containing at least two polymerizable groups that react with radicals.)

(In the general formula (III), R _{7 to} R ₁₆ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and are bonded to each other to form an aliphatic or aromatic ring. Note that it is necessary that at least two of R _{7 to} R ₁₆ are substituents containing a polymerizable group that reacts with a radical.

(In the general formula (IV), R _{17 to} R ₁₉ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and are bonded to each other to form an aliphatic or aromatic ring. Z represents a divalent nonmetallic atomic group necessary for forming an acidic nucleus in cooperation with adjacent atoms, wherein R _{17 to} R ₁₉ are polymerizable with at least two reacting with radicals. It must be a substituent containing a group.)

2. Wherein (B) the radical initiator compound capable of generating Le is, the 1 Symbol placement of the photosensitive composition characterized in that it is a hexaarylbiimidazole compound.
3. A lithographic printing plate precursor using the photosensitive composition according to 1 or 2 as a photosensitive layer.

  Although the mechanism of action of the present invention is not clarified, it is presumed as follows. A sensitizing dye having at least two polymerizable groups that react with at least one of a radical, an acid, and a base is brought into an electronically excited state with high sensitivity by laser irradiation at the time of exposure. Energy transfer, heat generation, etc. act on the coexisting initiator compound to cause a chemical change in the initiator compound to generate radicals, acids or bases. At least one of radicals, acids and bases generated here causes irreversible changes such as color development, decoloration, and polymerization in the coexisting polymerizable compound. Furthermore, since the sensitizing dye used in the present invention has at least two polymerizable groups on the dye structure, the dye itself can be crosslinked by polymerization, and a cured product having a more advanced crosslinked structure can be obtained. Therefore, it is considered that a photosensitive composition having high sensitivity and high economic efficiency (printing durability) can be obtained.

  According to the present invention, the photosensitivity is useful as a photosensitive layer of a lithographic printing plate precursor for scanning exposure that is highly sensitive to a laser of 350 nm to 850 nm and excellent in workability and economy, for example, suitable for a CTP system. A composition is provided.

Hereinafter, the present invention will be described in detail.
The present invention relates to the photosensitive compositions 1 and 2, and the lithographic printing plate precursor 3 described above. In the present specification, other matters are also described for reference.

The photosensitive composition of the present invention comprises
(A) a sensitizing dye having an absorption maximum λ _max at 350 nm to 850 nm and having at least two polymerizable groups that react with at least one of a radical, an acid, and a base;
(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 having an absorption maximum λ _max at 350 nm to 850 nm and having at least two polymerizable groups that react with at least one of a radical, an acid and a base, and (B) a radical, an acid or A photoinitiating system of the photosensitive composition is constituted by an initiator compound capable of generating a base. In this system, (A) an electronically excited state generated by light absorption of a sensitizing dye having an absorption maximum λ _max at 350 nm to 850 nm and having at least two polymerizable groups that react with at least one of radical, acid, or base The initiator compound undergoes a chemical change due to the action of electron transfer, energy transfer, heat generation, etc. to generate radicals, acids or bases.

  First, this photoinitiating system will be described.

An essential component of the photoinitiating system of the present invention, (A) a sensitizing dye having an absorption maximum λ _max at 350 nm to 850 nm and having at least two polymerizable groups that react with at least one of a radical, an acid, and a base One of the features is that it has particularly excellent absorption characteristics in the 350 nm to 850 nm region. Furthermore, (A) a sensitizing dye having a specific structure efficiently causes decomposition of various (B) initiator compounds and exhibits very high photosensitivity. In general, the sensitization mechanism of a photoinitiating system composed of 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 There are known routes such as decomposition of an agent compound from an electronically excited state, but it is estimated that the sensitizing dye of the present invention causes any of these types of sensitization reactions with excellent efficiency.

  In addition, in this invention, an initiator compound refers to the compound which produces | generates the radical, acid, or base used as the starting seed | species which starts and advances the polymerization (crosslinking) reaction of the coexisting polymeric compound by provision of energy.

(A) Sensitizing dye The sensitizing dye used in the photosensitive composition of the present invention is preferably a sensitizing dye having an absorption peak at 350 nm to 850 nm. If the absorption peak is less than 350 nm, a sufficient sensitization effect cannot be obtained because it is a short wave in view of the wavelength of the laser currently used for plate making. The same applies to the wavelength region exceeding 850 nm. From the viewpoint of practicality, a sensitizing dye having an absorption peak at 350 nm or more and 850 nm or less is selected.
Such a sensitizing dye preferably has a structure selected from a cyanine dye, a coumarin dye, a styryl dye, and a merocyanine dye. Among them, more preferred structures are sensitizing dyes represented by the following general formulas (I) to (IV).

In general formula (I), R ₁ and R ₂ each independently represent a monovalent organic group, and among them, may be a hydrocarbon group having 20 or less carbon atoms which may have a substituent. preferable.

Ar ₁ and Ar ₂ each independently represents an optionally substituted aromatic group or heterocyclic group, and preferred aromatic groups include a benzene ring and a naphthalene ring. Examples of the ring group include a pyridine ring and a pyrazine ring. Among these, a benzene ring or a naphthalene ring is particularly preferable.

Y ₁ and Y ₂ each independently represent a sulfur atom, an oxygen atom, a selenium atom, a dialkylmethylene group having 12 or less carbon atoms, or a —CH═CH— group, among which a dialkylmethylene such as a dimethylmethylene group Groups are preferred.

  M- represents an anion. M- is preferably a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, or a sulfonate ion, particularly preferably a perchlorate ion, a hexagonal salt, because of the storage stability of the recording layer coating solution. Fluorophosphate ions and aryl sulfonate ions. n represents 1 or 2.

Ar ₃ and Ar ₄ each independently represent an aromatic group or a heterocyclic group which may have a substituent.

Note that at least two of R ₁ , R ₂ , Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ must be substituents containing a polymerizable group that reacts with at least one of a radical, an acid, and a base.
(Subsequently, a substituent containing a polymerizable group that reacts with at least one of a radical, an acid, and a base may be referred to as a “specific substituent”.)

(In the general formula (II), X ₁ represents an oxygen atom, a sulfur atom, —CR′R ″ or —NR ′ ″ —. X ₂ represents an oxygen atom, a sulfur atom, ═CR′R or ═NR. R ′ and R each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and can be bonded to each other to form an aliphatic or aromatic ring, Furthermore, you may have a specific substituent as a substituent of the cyclic part.R < ₃ >, R < ₄ >, R < ₅ >, R < ₆ >, R'-R '''each independently represents a hydrogen atom or a monovalent nonmetallic atomic group. Each may be bonded to each other to form an aliphatic or aromatic ring, wherein R ₃ , R ₄ , R ₅ , R ₆ , R ′ to R ′ ″ are at least 2 One is a specific substituent.)

(In the general formula (III), R _{7 to} R ₁₆ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and are bonded to each other to form an aliphatic or aromatic ring. Note that at least two of R _{7 to} R ₁₆ need to be specific substituents.)

(In the general formula (IV), R _{17 to} R ₁₉ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and are bonded to each other to form an aliphatic or aromatic ring. Z represents a divalent nonmetallic atomic group necessary for forming an acidic nucleus in cooperation with an adjacent atom, wherein at least two of R _{17 to} R ₁₉ are specific substituents. )
Next, the specific substituent will be described in detail. The specific substituent is a substituent having a polymerizable group that reacts with at least one of a radical, an acid, and a base, and may have a linking chain interposed between the dye skeleton and the polymerizable group.

  Specifically, the structure of the specific substituent can be represented by the following general formula (V).

(In the general formula (V), L represents an alkylene group having 1 to 25 carbon atoms, and l is 0 or 1. X ₂ is an oxygen atom, a sulfur atom, —CR ₂₀ R ₂₁ — or —NR ₂₂ —. R ₂₀ , R ₂₁ and R ₂₂ each represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a halogen group, a cyano group, an alkoxycarbonyl group, an aryl group, or a heteroaryl group. It represents a polymerizable group that reacts with at least one of radical, acid, and base.)
Preferred examples of the polymerizable group represented by A include an acryl group, a methacryl group, a vinyl group, and an allyl group. An acryl group and a methacryl group are more preferable, and a methacryl group is still more preferable.

Next, the substituent of each general formula is demonstrated. R _{1 to} R ₂₂ , R ′, R ″, and R ′ ″ are at least two specific substituents in the structure represented by each general formula. Atoms, substituted or unsubstituted alkyl groups, alkoxy groups, halogen groups, cyano groups, alkoxycarbonyl groups, aryl groups, and heteroaryl groups are exemplified.

Next, preferred examples of R _{1 to} R ₂₂ , R ′, R ″, R ′ ″ 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 arylphosphonate 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.

  Preferred examples of the alkoxy group include a methoxy group and an ethoxy group, and the halogen is preferably a chloro group or a bromo group. More preferred is a chloro group. The alkoxycarbonyl group is preferably methoxycarbonyl or ethoxycarbonyl, more preferably methoxycarbonyl.

Specific examples of preferred aryl groups as R _{1 to} R ₂₂ , R ′, R ″, R ′ ″ include those in which 1 to 3 benzene rings form a condensed ring, benzene rings and 5-membered unsaturated groups. Examples of the ring formed a condensed ring can be mentioned, and 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. More preferred are a phenyl group and a naphthyl group.

Specific examples of the substituted aryl group preferable as R _{1 to} R ₂₂ , R ′, R ″, R ′ ″ include 1 (other than a hydrogen atom) as a substituent on the ring-forming carbon atom of the aforementioned aryl group. Those having a group of a valent nonmetallic atomic group are used. Examples of preferred substituents include the aforementioned 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, tolylphosphonatophenyl 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.

  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 as a particularly preferred example of the heteroaryl ring in the heteroaryl group, 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, phenoxazine and the like, and these are further may be benzo-fused or may have a substituent.

  Although the preferable specific example (exemplary compound D1-D30) of the sensitizing dye represented by General formula (1) based on this invention below is shown, this invention is not limited to these.

  The method for synthesizing the compounds represented by the general formulas (I) to (IV) will be specifically described with reference to the following examples.

  6.3 g of the compound A represented by the above formula and 4.42 g of the compound B were mixed with 50 ml of 2-propanol, 10 ml of acetic anhydride and 10 ml of triethylamine, and stirred at 80 ° C. for 3 hours. The reaction solution was cooled to room temperature and then poured into 200 ml of water to obtain a dark blue powder. This was reslurried twice with 150 ml of ethyl acetate to obtain 7.2 g of the desired compound D-1.

  Compound A (5.6 g) represented by the above formula and compound B (2.24 g) were mixed with 40 ml of anisole and stirred at 120 ° C. for 30 minutes. Next, 200 ml of water was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic tank composed of ethyl acetate-toluene was washed with an aqueous sodium chloride solution and then with water. After washing, the organic phase was concentrated to give a dark red solid. The obtained liquid was reslurried with methanol and then recrystallized with acetone to obtain 3.2 g of the intended compound D-8.

2.7 g of the compound A represented by the above formula and 4.85 g of the compound B were dissolved in 80 ml of THF and stirred at 0 ° C. for 30 minutes. To this reaction solution, 13.2 g of sodium hydride was added and stirred at 0 ° C. for 1 hour. Next, 2.7 g of compound A was added, and the mixture was further stirred for 2 hours.
The reaction solution was quenched with 5 ml of methanol and 10 ml of water and then poured into 200 ml of water, and the produced powder was collected by filtration. This powder was recrystallized from ethyl acetate to obtain 4.2 g of the target compound D-20.

  2.01 g of the compound A represented by the above formula and 0 g of compound B2 were mixed with 20 ml of methanol, 5 ml of pyrrolidine was added, and the mixture was stirred at 80 ° C. for 4 hours. After 4 hours, a yellow powder was formed in the reaction solution. This was collected by filtration while washing with methanol to obtain 2.8 g of the intended compound D-23.

  Other than the above-described compounds, they can be produced in the same manner as the above-described production methods.

  The sensitizing dyes represented by the general formulas (I) to (IV) used in the present invention can be further subjected to various chemical modifications for improving the characteristics of the photosensitive layer. For example, sensitizing dye and addition polymerizable compound structure (for example, acryloyl group or methacryloyl group) are bonded by a method such as covalent bond, ionic bond, hydrogen bond, etc. Unnecessary precipitation suppression of the dye from the subsequent film can be performed.

  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.

  Further, when the photosensitive composition of the present invention is used as a photosensitive layer of a lithographic printing plate precursor which is a preferred mode of use, it is hydrophilic for the purpose of enhancing the processing suitability for an alkaline or aqueous developer. It is effective to introduce a functional moiety (carboxyl group and its ester, sulfonic acid group and its ester, ethylene oxide group or other acid group or polar group). In particular, ester-type hydrophilic groups have a relatively hydrophobic structure in the photosensitive layer, so that they have excellent compatibility, and in the developer, acid groups are generated by hydrolysis, resulting in increased hydrophilicity. Have.

  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. Further, 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, a sensitizing dye having an absorption maximum λ _max at 350 nm to 850 nm and having at least two polymerizable groups that react with at least one of a radical, an acid, and a base, preferably a cyanine dye, A sensitizing dye selected from a coumarin dye, a styryl dye and a merocyanine dye, more preferably at least one sensitizing dye represented by the general formulas (I) to (IV) may be used. The details of the usage, such as what kind of structure is used, such as those with the modifications described above, whether they are used alone or in combination of two or more, and how much is added, are the final feeling It can be set as appropriate according to the performance design of the material. Moreover, compatibility with the photosensitive layer can be enhanced by using two or more kinds of the above 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. It is preferable to set it in the range of .5, preferably in the range of 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.

  The addition amount of the (A) sensitizing dye in the photosensitive composition of the present invention is usually in the range of 100 parts by mass of the total solid components of the photosensitive composition, preferably 0.05 to 30 parts by mass, more preferably 0. The range is from 1 to 20 parts by mass, and more preferably from 0.2 to 10 parts by mass. In this range, the photosensitive composition of the present invention is particularly useful as a material for forming a photosensitive layer of a lithographic printing original plate.

Next, the initiator compound (B) that 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 “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 together, 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 initiator compounds 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 of the initiator compounds belongs, the major feature of the sensitizing dye in the present invention is the initiation of any of these types. Even if combined with the agent 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 compound groups having the functions (1) and (2), FD Saeva, Top
ics in Current Chemistry, 156, 59 (1990); G. Maslak, Topics in Current Chemistry, 168, 1 (1993); B. Shuster et al, JACS,
112, 6329 (1990); D. F. A group of compounds that undergo oxidative or reductive bond cleavage as described in Eaton et al, JACS, 102, 3298 (1980), etc. is also known.

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) A compound that is reduced to generate 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 active species to be generated is a lophine radical, and in combination with a hydrogen donor if 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 an 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.), sulfonate esters of pyrogallol, naphthoquinone diazide-4 -Sulfonates can be reductively decomposed. As the active species, radicals and acids can be generated. Specific examples of sulfonic acid esters include European Patent Nos. 0290750, 046083, 156153, 271851, 0388343, U.S. Pat. Nos. 3,901,710 and 4,181,531, 60-198538, Japanese Patent Laid-Open No. 53-133022, nitrobenzester compounds, European Patent No. 099672, No. 84515, No. 199672, No. 0441115, No. 0101122, US Pat. No. 4,618,564, Nos. 4371605, 4431774, JP-A 64-18143, JP-A-2-245756, JP-A-4-365048, iminosulfonate compounds, JP-B-62-2223, Kosho 63-14340, JP 59-17483 Issue JP-like compounds described are listed, further, include, for example, compounds as shown below.

(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. Specific examples include the following compounds 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 —C (X) 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, Wakabayashi et al., Bull. Chem. Soc. Japan, 42, 2924 (1969), for example, 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, - 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- (acenaphth-5-yl) -4,6-bis Examples include compounds described in German Patent No. 3333724, such as -trichloromethyl-S-triazine, and the like.

  F.F. C. By Schaefer et al. Org. Chem. 29, 1527 (1964), such as 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-6-trichloromethyl-S-triazine, etc. be able to.

  Further, compounds described in JP-A No. 62-58241, 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 an 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,

(Here, R ⁵⁵ and R ⁵⁶ independently represent a hydrogen atom, an alkyl group having 1 to 14 carbon atoms, or an aryl group.), —COOR ⁵⁷ (wherein R ⁵⁷ represents a hydrogen atom, having 1 to 14 carbon atoms. an alkyl group or an aryl group,), -. COOR ⁵⁸ or -OR ⁵⁹ (wherein R ⁵⁸ is included those having as a substituent a) an alkyl group or an aryl group, 1 to 14 carbon atoms..

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 substituents of the substituted alkyl group. included.

In addition, examples of the heterocyclic group of R ^{51 to} R ⁵⁴ include a 5-membered or more, preferably 5 to 7-membered heterocyclic group containing at least one of N, S, and O. 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 with excellent sensitivity. Particularly, iodonium salts and sulfonium salts, particularly diaryliodonium and triarylsulfonium 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 maleate, 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 also 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 preferably 0.5 to 80 parts by mass, more preferably 1 to 50 parts by mass in 100 parts by mass of all the components of the photosensitive composition. Sufficient photosensitivity can be obtained by using within the range.
(C) Polymerizable compound The third essential component “(C) polymerizable compound that reacts with at least one of radical, acid or base” in the photosensitive composition of the present invention is generated by the above-mentioned photoinitiated photoreaction. In addition, the physical or chemical properties of the active species irreversibly change due to the action of the active species, resulting in 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 are described, for example, in J. Org. Am. Chem. Soc. , 108, 128 (1986), J. Am. Imaging. Soc. 30, 215 (1986), Israel. J. et al. 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 a specific example is, for example, ACS. Symp. Ser. 242, 11 (1984). JP-A-60-3625, U.S. Pat. Nos. 5102771, 5206317, 5212047, JP-A-4-26850, JP-A-3-1921731, JP-A-60-10247, No. 62-40450 each specification etc. are mentioned.

In the following, (C-1) addition, which is one of the main uses of the photosensitive composition of the present invention and is a (C) polymerizable compound particularly excellent for the purpose of obtaining a highly sensitive lithographic printing plate precursor The case where a polymerizable compound is used will be described as an example 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 planographic 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 area, that is, the cured film, those having three or more functionalities are preferable. Further, 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. Regarding the compounding ratio of the addition polymerizable compound in the photosensitive layer, a larger amount is more advantageous in terms of sensitivity, but if it is too much, an 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 a developer may occur. From these viewpoints, the addition polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass in the solid component of the photosensitive composition. 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 property, 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 to enable 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 the content exceeds 90% by mass in the composition, a favorable result is not given in terms of the image strength to be formed. Preferably it is 30-85 mass%. Further, when the non-polymerizable compound is used as the polymerizable compound, the blending ratio of the non-polymerizable compound and the linear organic polymer is 1/9 to 7/3 by mass ratio. It is preferable to do this. 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, production method, and the like. 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. Presumed to be. 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 into highly active radicals or act as chain transfer agents: For example, a group of compounds having SH, PH, SiH, GeH in the molecule is 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 dye. 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 preferably 0.05 to 100 parts by mass, more preferably 1 to 80 parts by mass, and further preferably 3 to 50 parts by mass with respect to 100 parts by mass of the polymerizable compound.
(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, so-called plate inspection properties such as visibility after plate making and suitability for an image density measuring machine as a printing plate can be improved. As a colorant, many dyes cause a decrease in the sensitivity of the photosensitive layer. Therefore, it is particularly preferable to use a pigment as the colorant. Specific examples include pigments such as phthalocyanine pigments, azo pigments, carbon black and titanium oxide, and dyes such as ethyl violet, crystal violet, azo dyes, anthraquinone dyes, and cyanine dyes. The addition amount of the dye and the pigment 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 plasticizer, or ink on the surface of the photosensitive layer is 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. The compounding quantity of an agent can be added 10 mass% or less with respect to the total mass of a polymeric compound 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.

  Hereinafter, the usage method of the photosensitive composition of this invention is demonstrated.

The photosensitive composition of the present invention can be applied as a photosensitive layer on a support and used as an image recording material. The coating amount of the photosensitive layer on the support is preferably selected according to the intended 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.

When the photosensitive composition of the present invention is used as a photosensitive layer of an image recording material such as a lithographic printing plate precursor, from the viewpoint of sensitivity and storage stability, the general formula (I), ( An initiator system using a compound represented by II), (III) or general formula (IV) and combining a titanocene compound or a hexaarylbiimidazole compound as an initiator compound is preferable, and an initiator system combining a hexaarylbiimidazole compound Are more preferable, and an embodiment containing an initiation system composed of these and (C-1) an addition polymerizable compound is particularly preferable.
(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 also 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 conventionally known and used aluminum plates 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, and 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 with the aluminum plate as the 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.
(Back coat)
After the surface treatment is applied to the support or the intermediate layer is formed, a back coat can be provided on the back surface of the support, if necessary.

Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.
(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 developer when these photosensitive compositions are used for preparing a lithographic printing plate, a developer as 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. A suitable inorganic alkaline agent or an aqueous solution of an organic alkaline agent such as monoethanolamine or diethanolamine is suitable. It is added so that the concentration of such an 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 carry out whole surface post-heating or whole surface exposure on the developed image. Usually, heating before development is preferably performed under mild conditions of 150 ° C. or less. 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 high 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, Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), He—Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and solid laser as Nd: YAG (YVO ₄ ) and SHG crystal × two combinations (355 nm, 5 mW to 1 W), Cr: LiSAF and SHG crystal combination (430 nm, 10 mW), as a semiconductor laser system, a KNbO ₃ ring resonator (430 nm, 30 mW), Combination of waveguide type wavelength conversion element and AlGaAs, InGaAs semiconductor (380 nm to 450 nm, 5 mW to 100 mW), combination of waveguide type wavelength conversion element and AlGaInP, AlGaAs semiconductor (300 nm to 350 nm, 5 mW to 100 mW), A In addition, 1GaInN (350 nm to 450 nm, 5 mW to 30 mW), and N ₂ laser (337 nm, pulse 0.1 to 10 mJ), XeF (351 nm, pulse 10 to 250 mJ) and the like can be used as the pulse laser.

  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 the internal drum system ・ Multi-beam exposure system that uses many (10 or more) semiconductor lasers with the flat bed system ・ Many semiconductor lasers with the 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 ) is generally used.
The equation (eq1) is established among the exposure area S (cm ² ) of the photosensitive material, the power q (W) of one laser light source, the number of lasers n, and the total exposure time t (s).

X · S = n · q · t (eq1)
i) In the case of the internal drum (single beam) system, the laser rotational speed f (radian / s), the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dot / cm), and the total exposure time t (s) In general, equation (eq2) holds.

f · Z · t = Lx (eq2)
ii) In the case of the external drum (multi-beam) system, the drum rotation speed F (radians / s), the photosensitive material sub-scanning length Lx (cm), the resolution Z (dots / cm), the total exposure time t (s), the 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 rotation speed H (radian / s) of the polygon mirror, the sub-scanning length Lx (cm) of the photosensitive material, the resolution Z (dot / 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 (2560 dpi) required for an actual printing plate, plate size (A1 / B1, sub-scanning 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 multi-beam exposure method of a semiconductor laser is more preferable in the photosensitive 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.

  Further, as other exposure light for the photosensitive composition of the present invention, ultrahigh pressure, high pressure, medium pressure, 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 tackiness due to 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 to 19 and Comparative Examples 1 to 6]
(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 display according to JIS B0601).

The following sol-gel reaction liquid 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 backcoat layer having a coating amount after drying of 70 mg / m ^2. It was created.
Sol-gel reaction solution Tetraethyl silicate 55 parts by weight Water 25 parts by weight Methanol 10 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 a raw material solution having the following composition.
Raw material liquid Pyrogallol formaldehyde condensation resin (molecular weight 2000) 6 parts by mass Dimethyl phthalate 6 parts by mass Fluorosurfactant 0.7 parts by mass (N-butylperfluorooctanesulfonamidoethyl 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 (Preparation 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 and dried at 80 ° C. for 2 minutes to form a photosensitive layer. .

・ The above polymerizable compound 1.5 g
・ Binder polymer Allyl methacrylate / Methacrylic acid /
N-isopropylacrylamide copolymer 2.0 g
(Molar ratio of copolymerization 67/13/20)
-Photopolymerization initiation system (described in Table 1)
Sensitizing dye Xg
Initiator compound Yg
Co-sensitizer Zg
・ Other components Fluorine nonionic surfactant (F-177P) 0.02 g
Thermal polymerization inhibitor N-nitrosophenyl hydroxyl 0.01 g
Amine aluminum salt Pigment dispersion 2.0 g
Composition of pigment dispersion Composition: Pigment Blue 15: 6 15 parts by weight
Allyl methacrylate / methacrylic acid copolymer 10 parts by weight
(Copolymerization molar ratio 83/17)
15 parts by weight of cyclohexanone
20 parts by weight of methoxypropyl acetate
40 parts by weight of propylene glycol monomethyl ether / solvent methyl ethyl ketone 20.0 g
Propylene glycol monomethyl ether 20.0 g
(Preparation 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 such that the dry coating weight was 2 g / m ² and dried at 100 ° C. for 2 minutes.
<Sensitivity evaluation method by exposure wavelength>
(Evaluation of sensitivity 1: 830 nm exposure)
The obtained negative lithographic printing plate precursor is exposed with a Trendsetter 3244VFS manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, a plate surface energy of 100 mJ / cm ² , and a resolution of 2400 dpi. did.

  After the exposure, the film was developed using an automatic processor Stablon 900N manufactured by Fuji Photo Film Co., Ltd. As the developer, a 1: 4 water diluted solution of DV-2 manufactured by Fuji Photo Film Co., Ltd. was used for both the feed solution and the replenisher solution.

  The temperature of the developer was 30 ° C. As the finisher, a 1: 1 water dilution (pH = 10.8) of FN-6 manufactured by Fuji Photo Film Co., Ltd. was used.

The amount of energy necessary for recording was calculated based on the line width and laser output of the image obtained by the above exposure (with an infrared laser having a wavelength of about 830 to 850 nm) and development, the loss in the optical system, and the scanning speed. The smaller the value, the higher the sensitivity. The results are also shown in Table 1.
(Evaluation of sensitivity 2: 532, 405 nm exposure)
A Fuji step guide made by Fuji Photo Film Co., Ltd. (gray scale whose transmission optical density changes discontinuously at Δ = 0.15) was brought into close contact with the obtained lithographic printing plate precursor, and an optical filter (Kenko) was used. Using a xenon lamp through BP-53 (for 532 nm) and BP-40 (for 405 nm), exposure was performed so as to obtain a known exposure energy. As the optical filter, Kenko BP-53 and 40 capable of exposure with monochromatic light at 532 or 405 nm were used for the purpose of estimating the suitability for exposure to a short-wave semiconductor laser. Thereafter, the film was immersed in a developer having the following composition at 25 ° C. for 10 seconds, developed, and the sensitivity (clear sensitivity) was calculated from the maximum number of steps at which the image was completely removed. The results are shown in Table 1. Here, the clear sensitivity represents the minimum energy required for image formation, and the lower this value, the higher the sensitivity.
(Developer composition)
1K potassium silicate 2.4g
Potassium hydroxide 0.2g
Compound of the following formula 1 5.0 g
91.3g of water
0.1g of ethylenediaminetetraacetic acid, 4Na salt

Measured acid value obtained by NaOH titration 1.08 meq / g
Weight average molecular weight determined by GPC measurement 52,000 <Sensitivity in difference in exposure wavelength>
Points to note about the above sensitivity. The smaller the sensitivity value, the higher the sensitivity, but the ones with different exposure wavelengths cannot be compared.

This is because the amount of energy per photon differs when the light source wavelength is different, so even if it is simply considered, it is possible to sensitize even if the exposure amount is small as the short wave usually becomes short. Sensitivity. Therefore, in Table 1, the sensitivity comparison between different exposure conditions is meaningless, and it is necessary to see the difference between the example and the comparative example under the same exposure condition.
(Print durability test)
R201 manufactured by Roland was used as the printing machine, and GEOS-G (N) manufactured by Dainippon Ink was used as the ink. The printed matter in the solid image area was observed, and the printing durability was examined based on the number of sheets on which the image began to fade. The higher the number, the better the printing durability.

  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. The structures of the sensitizing dyes (H-1) to (H-4), the initiators (T-1) to (T-4), and the co-sensitizer (R-1) are as shown below. The following sensitizing dyes (H-1) to (H-4) used in Comparative Examples are dye compounds outside the scope of the present invention.

  As is apparent from Table 1, the lithographic printing plate precursor using the photosensitive composition of the present invention for the photosensitive layer has excellent sensitivity when, for example, Examples 4, 7, 12, and 14 are compared with Comparative Examples 1 to 4. It can be seen that it has excellent printing durability. Moreover, it turns out that a methacryl group gives a better result as a polymeric group from the comparison of Example 5 and 7. FIG.

  The sensitizing dye used in the present invention can achieve both extremely high sensitivity and printing durability in the presence of the initiator compound of the present invention, particularly hexaarylimidazole. Since no image could be formed when no initiator was present, it was also found that the coexistence of the initiator compound of the present invention is a very important point.

Claims (3)

(A) a sensitizing dye having an absorption maximum λ _max at 350 nm to 850 nm and having at least two polymerizable groups that react with radicals;
(B) an initiator compound capable of generating radicals, and (C) a polymerizable compound that reacts with radicals,
And (A) the sensitizing dye is at least one of the following formulas (I) to (IV).

(In general formula (I), R ₁ and R ₂ each independently represents a monovalent organic group, and Ar ₁ and Ar ₂ each independently represent an aromatic group optionally having a substituent, or a heterocyclic group, Y _1, Y ₂ each independently represent a sulfur atom, an oxygen atom, a selenium atom, a carbon atom number of 12 or less dialkyl methylene group, or -CH = CH- group, M ^- Represents an anion, n represents 1 or 2. Ar ₃ and Ar ₄ each independently represents an aromatic group or a heterocyclic group which may have a substituent, wherein R ₁ , (At least two of R ₂ , Ar ₁ , Ar ₂ , Ar ₃ , and Ar ₄ must be substituents containing a polymerizable group that reacts with a radical.)

(In the general formula (II), X ₁ represents an oxygen atom, a sulfur atom, —CR′R ″ or —NR ′ ″ —. X ₂ represents an oxygen atom, a sulfur atom, ═CR′R or ═NR ′. R 'and R each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and can be bonded to each other to form an aliphatic or aromatic ring; It may have a substituent containing a polymerizable group that reacts with a radical as a substituent of the cyclic part.R ₃ , R ₄ , R ₅ , R ₆ , R ′ to R ′ ″ are each independently a hydrogen atom or Represents a monovalent non-metallic atomic group, and can be bonded to each other to form an aliphatic or aromatic ring, wherein R ₃ , R ₄ , R ₅ , R ₆ , R′˜ R ′ ″ is required to be a substituent containing at least two polymerizable groups that react with radicals.)

(In the general formula (III), R _{7 to} R ₁₆ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and are bonded to each other to form an aliphatic or aromatic ring. Note that it is necessary that at least two of R _{7 to} R ₁₆ are substituents containing a polymerizable group that reacts with a radical.

(In the general formula (IV), R _{17 to} R ₁₉ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and are bonded to each other to form an aliphatic or aromatic ring. Z represents a divalent nonmetallic atomic group necessary for forming an acidic nucleus in cooperation with an adjacent atom, wherein R _{17 to} R ₁₉ are polymerizable with at least two reacting with radicals. It must be a substituent containing a group.)   The photosensitive composition according to claim 1, wherein the initiator compound capable of generating the (B) radical is a hexaarylbiimidazole compound.   A lithographic printing plate precursor using the photosensitive composition according to claim 1 for a photosensitive layer.