JP2008201912A - Photopolymerizable composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photopolymerizable composition which has a high sensitivity and is excellent in polymerizability. <P>SOLUTION: The photopolymerizable composition comprises a polymerizable compound having an ethylenically unsaturated bond, a free-radical generator represented by formula (1): D-L-A (wherein D is a light-absorbing moiety showing an absorption having an absorption coefficient of ≥1,000 in a wavelength range longer than 300 nm; A is an active moiety which interacts with the light-excited light-absorbing moiety D to generate a radical; and L is a linking group which links the light-absorbing moiety D with the active moiety A) and a cosensitizer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radically polymerizable composition exhibiting high sensitivity to light, and specifically includes inks, color filters, holograms, proofs, sealants, adhesives, lithographic printing, resin relief printing, photoresists and the like. The present invention relates to a photopolymerizable composition that can be suitably used in a wide range of fields.

The photopolymerizable composition basically includes a photopolymerization initiator and an addition-polymerizable compound containing two or more ethylenically unsaturated bonds in the molecule (hereinafter referred to as “polyfunctional monomer”). When irradiated with light, it hardens and changes its tackiness or becomes insoluble in a solvent. Utilizing these properties, it is widely used for photography, printing, metal surface processing, ink and the like. Functions and application examples of the photopolymerizable composition are described in many books (for example, see Non-Patent Document 1 or 2).
In such fields, a photopolymerizable composition having high sensitivity to light of 300 nm or more, particularly visible light, forms an image with a short exposure time when used as an image forming material for printing plates, resists, and holography. It is extremely useful because it shortens the working time and improves the working efficiency, and is used in the field of printing plates and photoresists as a laser direct drawing type photosensitive material. Since one of the materials that determine such properties is a photopolymerization initiator, research on increasing its sensitivity has been actively conducted.
As one means for increasing the sensitivity of the photopolymerizable composition, Patent Document 1 proposes the use of a radical polymerization initiator (linking initiator) in which a light absorption part and a radical generation part are linked. Such a polymerization initiator is advantageous in that it efficiently causes electron transfer or energy transfer after light absorption and easily generates an initiation radical. However, since the molecular weight is increased by linking, the size of the generated radical is large, the diffusibility of the radical is deteriorated, and there is a problem that the original efficient radical generation cannot be fully utilized.
JP-A-2-63054 J. et al. “Light Sensitive Systems” by Kosar (J. Wiley & Sons, New York, 1965, pp. 158-193) K. I. Jacobson, R.A. E. “Imaging Systems” by Jacobson (J. Wiley & Sons, New York, 1976, 181-222)

  An object of the present invention is to provide a photopolymerizable composition having high sensitivity and excellent polymerizability.

  As a result of intensive studies, the present inventors have remarkably increased sensitivity by adding a co-sensitizer to a photopolymerizable composition containing a radical polymerization initiator in which a light absorption part and a radical generation part are linked, It has been found that it exhibits excellent polymerizability. That is, it has been found that by including a co-sensitizer in the photopolymerizable composition, a low diffusibility linking initiator radical becomes a highly diffusible co-sensitizer radical and the polymerization reactivity is increased. . The present invention has been made based on such findings.

The problems of the present invention have been solved by the following means.
[1] A photopolymerizable composition comprising a polymerizable compound having an ethylenically unsaturated bond, a radical generator represented by the following general formula (1), and a co-sensitizer.
General formula (1) D-LA
(In the formula, D represents a light absorbing part having an absorption coefficient of 1000 or more in a wavelength region longer than 300 nm, and A represents an active part that interacts with the photoexcited light absorbing part D to generate radicals. , L represents a linking group for linking the light absorbing part D and the active part A.)
[2] The co-sensitizer is at least one compound selected from the group consisting of thiol compounds, sulfide compounds, amino compounds, amino acid compounds, trichloromethyl compounds, onium salt compounds, and oxime compounds. The photopolymerizable composition according to item [1], wherein:
[3] The co-sensitizer is contained in an amount of 0.5 to 20% by mass with respect to the total solid content of the photopolymerizable composition, according to the item [1] or [2]. Photopolymerizable composition.
[4] Any one of [1] to [3], wherein the light absorption part D in the general formula (1) includes a cyanine dye, a hemicyanine dye, a merocyanine dye, a coumarin dye, or a hemioxonol dye. Item 1. The photopolymerizable composition according to item 1.

  The photopolymerizable composition of the present invention has high sensitivity and excellent polymerizability.

Hereinafter, the present invention will be described in detail.
[Radical generator]
The radical generator used in the present invention is a compound represented by the following general formula (1).
General formula (1) D-LA
(In the formula, D represents a light absorbing part having an absorption coefficient of 1000 or more in a wavelength region longer than 300 nm, and A represents an active part that interacts with the photoexcited light absorbing part D to generate radicals. , L represents a linking group for linking the light absorbing part D and the active part A.)

  In the radical generator (photopolymerization initiator) represented by the general formula (1) used in the present invention, the active part A and the light absorbing part D are arranged in a portion closer to the covalent bond, so that the photoelectron transfer is performed. Occurring efficiently, and therefore higher radical generation compared to the case where the active part A and the light absorbing part D are not connected (when the compound having the active part A and the compound having the light absorbing part D are used in combination) Shows efficiency. In addition, the effect does not decrease even when the addition amount decreases, and high radical generation occurs in the low addition concentration region. Therefore, it is possible to produce a cured product that is less colored by the pigment portion. Moreover, visible light curing is possible without impairing the original color, and curing in a thick film system or a dilute system can be performed efficiently.

In the general formula (1), D represents a light absorption part having an absorption coefficient of 1000 or more in a wavelength region longer than 300 nm. The light absorption part D means the residue remove | excluding the coupling | bond part with the coupling group L from the compound which has the light absorption part D. FIG. The absorption wavelength region is preferably 400 to 900 nm.
Examples of the compound having the light absorption part D include various dyes, condensed polycyclic aromatic compounds, condensed polycyclic heteroaromatic compounds, and aromatic ketone compounds.

  As the dye, a cationic dye and a nonionic dye are preferable. Cationic dyes are those in which quaternary ammonium is present in the coloring conjugated system of dye molecules. Specific examples include cyanine dyes, hemicyanine dyes, triarylmethane dyes, styryl dyes, diarylmethane dyes, and fluorane dyes, but are not limited thereto. The nonionic dye is a dye having no counter anion and represents a dye that does not form a salt with the anion. Specific examples include merocyanine dyes, oxonol dyes, coumarin dyes, azo dyes, azomethine dyes, styryl-based dyes, stilbene dyes, hemioxonol dyes, dyes having a vinyl ketone bond, quinone dyes, and phthalocyanine dyes. It is not limited to. Among the dyes, cyanine dyes, hemicyanine dyes, merocyanine dyes, coumarin dyes, and hemioxonol dyes are preferable in terms of high sensitivity.

  In addition, examples of the condensed polycyclic aromatic compound include anthracene, phenanthrene, pyrene, and derivatives thereof, and examples of the condensed polycyclic heteroaromatic compound include acridine, carbazole, phenothiazine, and the like, and derivatives thereof. Is mentioned. Examples of the aromatic ketone compound include ketone compounds such as benzophenone, thioxanthone, anthraquinone, naphthoquinone, acridone, and fluorenone, and derivatives thereof. In addition, the cationic dye residue, nonionic dye residue, condensed polycyclic aromatic compound residue, condensed polycyclic heteroaromatic compound residue, and aromatic ketone compound residue may be substituted with a substituent.

  Examples of the substituent include a carboxyl group, a sulfo group, a cyano group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom), a hydroxy group, and an alkoxycarbonyl group having 2 to 30 carbon atoms (for example, a methoxycarbonyl group, ethoxycarbonyl). Group, benzyloxycarbonyl group), C2-C30 alkylsulfonylaminocarbonyl group, arylsulfonylaminocarbonyl group, alkylsulfonyl group, arylsulfonyl group, C2-C30 acylaminosulfonyl group, C1-C30 Alkoxy groups (for example, methoxy group, ethoxy group, benzyloxy group, phenoxyethoxy group, phenethyloxy group, etc.), alkylthio groups having 1 to 30 carbon atoms (for example, methylthio group, ethylthio group, dodecylthio group, etc.), carbon number 6-30 aryloxy (E.g., a phenoxy group, p- tolyloxy group, 1-naphthoxy group, 2-naphthoxy group), a nitro group, an alkyl group having 1 to 30 carbon atoms, an alkoxycarbonyl group, an aryloxycarbonyl group,

C2-C30 acyloxy group (for example, acetyloxy group, propionyloxy group, etc.), C2-C30 acyl group (for example, acetyl group, propionyl group, benzoyl group, etc.), carbamoyl group (for example, carbamoyl group) N, N-dimethylcarbamoyl group, morpholinocarbonyl group, piperidinocarbonyl group, etc.), sulfamoyl group (for example, sulfamoyl group, N, N-dimethylsulfamoyl group, morpholinosulfonyl group, piperidinosulfonyl group, etc.) An aryl group having 6 to 30 carbon atoms (for example, phenyl group, 4-chlorophenyl group, 4-methylphenyl group, α-naphthyl group, etc.), substituted amino group (for example, amino group, alkylamino group, dialkylamino group, Arylamino group, diarylamino group, acylamino group, etc.), substituted urea De group, a substituted phosphono group, and a heterocyclic group. Here, the carboxyl group, the sulfo group, the hydroxy group, and the phosphono group may be in a salt state.

In the general formula (1), A represents an active part that interacts with the photoexcited light absorbing part D to generate radicals. The active part A means a residue obtained by removing the binding part with the linking group L from the compound having the active part A.
Examples of the compound having the active part A include bisimidazole compounds, diphenyliodonium, hydroxyalkyl ketones, triphenylsulfonium salts and other onium compounds, trichloromethyl-substituted S-triazine compounds, N-phenylglycine, triethanolamine, hydrazine, and the like. Amines, phosphorus compounds such as triphenylphosphine and tri-n-butylphosphine, sulfinic acids such as sodium p-toluenesulfinate, sulfonic acid esters such as p-toluenesulfonic acid methyl ester, oxazole, oxadiazole, Heterocyclic compounds such as imidazole, enolate compounds such as dimedone, tin compounds such as tributylbenzyltin, pyridinium salts such as 1-methoxy-4-carbomethoxypyridinium tetrafluoroborate ( This is described in “Research Disclosure” Vol. 200, December 1980, Item 20036.), borate compounds such as allyl thiourea, oxime ester, triphenyl-n-butyl borate, and the like. it can.

  In the general formula (1), L represents a linking group that connects the light absorption part D and the active part A, and represents a divalent linking group or a single bond. As the divalent linking group represented by L, those composed of an atom or an atomic group containing at least one of a carbon atom, a nitrogen atom, a sulfur atom and an oxygen atom are preferable. Preferably, an alkylene group (for example, methylene, ethylene, propylene, butylene, pentylene), an arylene group (for example, phenylene, naphthylene), an alkenylene group (for example, ethenylene, propenylene), an alkynylene group (for example, ethynylene, propynylene), an amide Group, ester group, sulfoamide group, sulfonic acid ester group, ureido group, sulfonyl group, sulfinyl group, thioether group, ether group, carbonyl group, -N (Ra)-group (where Ra is a hydrogen atom, substituted or unsubstituted Represents a substituted alkyl group, a substituted or unsubstituted aryl group), a heterocyclic divalent group (for example, 6-chloro-1,3,5-triazine-2,4-diyl group, pyrimidine-2,4- Diyl group, quinoxaline-2,3-diyl group) or a combination thereof. Include a divalent linking group of 1 to 20 carbon atoms. These divalent linking groups may be further substituted, and examples of the substituent include those listed as the substituents of the aforementioned aromatic ketone compound residue.

  More preferably, the divalent linking group or single bond represented by L is an alkylene group having 1 to 20 carbon atoms (for example, methylene, ethylene, propylene, butylene), an arylene group having 6 to 20 carbon atoms ( For example, phenylene, naphthylene), a divalent linking group having 1 to 20 carbon atoms, or a single bond formed by combining one or more alkenylene groups having 2 to 20 carbon atoms (for example, ethenylene or propenylene) Is mentioned.

  Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited thereto.

  The compound represented by the general formula (1) can be obtained by reacting and condensing the compound having the light absorption part D and the compound having the active part A. As the condensation reaction, a general condensation reaction can be used. Usually, the reaction can be carried out using heating, a catalyst or a condensing agent.

  The content of the radical generator represented by the general formula (1) in the photopolymerizable composition of the present invention is preferably 0.01 to 40 with respect to the total amount (100% by mass) of the photopolymerizable composition. It is 0.05 mass%, More preferably, it is 0.05-20 mass%, More preferably, it is 0.1-10 mass%.

[Polymerizable compound having an ethylenically unsaturated bond]
The photopolymerizable composition of the present invention contains a polymerizable compound having an ethylenically unsaturated bond (hereinafter sometimes referred to as “polymerizable compound”). The polymerizable compound is a polymerizable compound having at least one ethylenically unsaturated double bond in the molecule, and the polymerizable compound is not particularly limited and may be appropriately selected depending on the purpose. For example, acrylic acid derivatives such as acrylic acid esters and acrylamides, acrylic acid and salts thereof, methacrylic acid derivatives such as methacrylic acid esters and methacrylamides, methacrylic acid and salts thereof, maleic anhydride, maleic acid Examples thereof include esters, itaconic acid, itaconic acid esters, styrenes, vinyl ethers, vinyl esters, N-vinyl heterocycles, allyl ethers, allyl esters, and the like.

  The polymerizable compound contains one or two or more olefinic double bonds, and may have either a low molecular weight (monomer property) or a high molecular weight (oligomer property). Examples of the monomer containing a double bond include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, and other alkyl or hydroxyalkyl acrylates or methacrylates. Etc. Silicon acrylate is also advantageous. Other examples include acrylonitrile, acrylamide, methacrylamide, N-substituted (meth) acrylamide, vinyl esters such as vinyl acetate, vinyl ethers such as isobutyl vinyl ether, styrene, alkyl- and halostyrenes, N-vinyl pyrrolidone, Examples include vinyl chloride and vinylidene chloride.

  Examples of monomers containing two or more double bonds include diacrylates such as ethylene glycol, propylene glycol, neopentyl glycol, hexamethylene glycol or bisphenol A, and 4,4′-bis (2-acryloyl). Oxyethoxy) diphenylpropane, trimethylolpropane triacrylate, pentaerythritol triacrylate or tetraacrylate, vinyl acrylate, divinylbenzene, divinyl succinate, diallyl phthalate, triallyl phosphate, triallyl isocyanurate or tris (2-acryloylethyl) An isocyanurate etc. are mentioned.

  Examples of relatively high molecular weight (oligomeric) polyunsaturated compounds include epoxy resins having (meth) acrylic groups, polyesters having (meth) acrylic groups, polyesters containing vinyl ethers or epoxy groups, polyurethanes and polyethers. Can be mentioned. In addition, examples of unsaturated oligomers include unsaturated polyester resins that are usually made from maleic acid, phthalic acid and one or more diols and have a molecular weight of about 500-3000. In addition, it is also possible to use vinyl ether monomers and oligomers and malate-terminated oligomers having polyester, polyurethane, polyether, polyvinyl ether and epoxy backbones. Particularly suitable is a combination of an oligomer having a vinyl ether group and a polymer described in WO90 / 01512 pamphlet. Also suitable are copolymers of vinyl ether and maleic acid functionalized monomers. Such unsaturated oligomers can also belong as prepolymers.

  Particularly suitable examples include ethylenically unsaturated carboxylic acids and esters of polyols or polyepoxides, and polymers having ethylenically unsaturated groups in the main or side chain, such as unsaturated polyesters, polyamides and polyurethanes and copolymers thereof, alkyds Resins, polybutadiene and butadiene copolymers, polyisoprene and isoprene copolymers, polymers and copolymers containing (meth) acrylic groups in the side chain, and mixtures of one or more such polymers.

  Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, cinnamic acid, and unsaturated fatty acids such as linoleic acid or oleic acid. Of these, acrylic acid and methacrylic acid are preferable.

  Suitable polyols are aromatic and in particular aliphatic and cycloaliphatic polyols. Examples of aromatic polyols include hydroquinone, 4,4'-dihydroxydiphenyl, 2,2-di (4-hydroxyphenyl) propane, novolac and resorcin. Examples of polyepoxides are those based on the above polyols, in particular aromatic polyols, and epichlorohydrin. Other suitable polyols are polymers and copolymers containing hydroxyl groups in the polymer chain or side chain, for example polyvinyl alcohol and their copolymers or polyhydroxyalkyl methacrylates or their copolymers. Suitable further polyols are oligoesters having hydroxyl end groups.

  Examples of aliphatic and cycloaliphatic polyols are preferably alkylene diols having 2 to 12 carbon atoms, such as ethylene glycol, 1,2- or 1,3-propanediol, 1,2-, 1 , 3- or 1,4-butanediol, pentanediol, hexanediol, octanediol, dodecanediol, diethylene glycol, triethylene glycol; preferably polyethylene glycol having a molecular weight of 200 to 1500, 1,3-cyclopentanediol, 1 , 2-, 1,3- or 1,4-cyclohexanediol, 1,4-dihydroxymethylcyclohexane, glycerol, tris (β-hydroxyethyl) amine, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol And sorbitol.

  Polyols can be partially or fully esterified with one carboxylic acid or with a different unsaturated carboxylic acid, and free hydroxyl groups can be modified in the partial ester, eg, other carboxylic acids It can be etherified or esterified with.

  As ester, the following are mentioned, for example. Trimethylolpropane triacrylate, trimethylolethane triacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, penta Erythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tripentaerythritol octaacrylate, pentaerythritol Dimethacrylate, pentaerythritol trimethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol tetramethacrylate,

Tripentaerythritol octamethacrylate, pentaerythritol diitaconate, dipentaerythritol trisitaconate, dipentaerythritol pen titaconate, dipentaerythritol hexaitaconate, ethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,3 -Butanediol dimethacrylate, 1,4-butanediol diitaconate, sorbitol triacrylate, sorbitol tetraacrylate, pentaerythritol-modified triacrylate, sorbitol tetramethacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, oligoester acrylate and methacrylate, glycerol Diacrylate and triacrylate, 1,4-si B hexane diacrylate, bis acrylate and bismethacrylates of polyethylene glycol having a molecular weight of 200 to 1500, or mixtures thereof.

  Also suitable as said polymerizable compounds are aromatic, cycloaliphatic and aliphatic having the same or different unsaturated carboxylic acids and preferably 2-6, in particular 2-4 amino groups. Amide with polyamine. Examples of such polyamines include ethylenediamine, 1,2- or 1,3-propylenediamine, 1,2-, 1,3- or 1,4-butylenediamine, 1,5-pentylenediamine, 1, 6-hexylenediamine, octylenediamine, dodecylenediamine, 1,4-diaminocyclohexane, isophoronediamine, phenylenediamine, bisphenylenediamine, di-β-aminoethyl ether, diethylenetriamine, triethylenetetramine, di (β -Aminoethoxy)-or di (β-aminopropoxy) ethane. In addition, polymers and copolymers with additional amino groups, preferably in the side chain, and oligoamides with amino end groups are suitable. Examples of such unsaturated amides are methylene bisacrylamide, 1,6-hexamethylene bisacrylamide, diethylenetriamine tris methacrylamide, bis (methacrylamide propoxy) ethane, β-methacrylamide ethyl methacrylate and N-[(β-hydroxyethoxy. ) Ethyl] acrylamide and the like.

  Suitable unsaturated polyesters and polyamides are derived, for example, from maleic acid and from diols or diamines. Some of the maleic acid can be replaced with other dicarboxylic acids. They can be used together with ethylenically unsaturated comonomers such as styrene. Polyesters and polyamides can be derived from dicarboxylic acids, from ethylenically unsaturated diols or diamines, in particular from those with relatively long chains, for example from 6 to 20 carbon atoms. Examples of polyurethanes include those composed of saturated or unsaturated diisocyanates and unsaturated, or saturated diols, respectively.

  Polybutadiene and polyisoprene and copolymers thereof are known. Examples of suitable comonomers are olefins such as ethylene, propene, butene and hexene, (meth) acrylates, acrylonitrile, styrene or vinyl chloride. Polymers having (meth) acrylate groups in the side chain are likewise known. For example, it can be obtained as a reaction product of an epoxy resin based on novolak and (meth) acrylic acid, or a homo- or copolymer of vinyl alcohol or (meth) acrylic acid and its hydroxyalkyl derivative esterified Or a homo- or copolymer of (meth) acrylate esterified with hydroxyalkyl (meth) acrylate.

  The polymerizable compound may be a compound having a site that expresses another function in the structure depending on the use of the photopolymerizable composition. For example, the photopolymerizable composition is used as a recording material. In this case, it may have a site that promotes the color development reaction of the color forming component constituting the image portion or a site that suppresses color development. These will be described later.

  As content of the polymerizable compound which has the said ethylenically unsaturated bond, it is 10-99 mass% normally in the total mass of a photopolymerizable composition, and 30-95 mass% is preferable.

[Co-sensitizer]
The photopolymerizable composition of the present invention contains a co-sensitizer. In the present invention, the co-sensitizer has functions such as further improving the sensitivity of the sensitizer and initiator to actinic radiation or suppressing the inhibition of polymerization of the polymerizable compound by oxygen.
The mechanism varies depending on the type of co-sensitizer and will be described by taking a thiol compound as an example. Thiol compounds are generally known as chain transfer agents. That is, it is a compound that undergoes a hydrogen abstraction reaction with a radical generated from a linking initiator and inactivates the original radical to cause an initiation reaction by itself becoming a radical. In general, radicals generated from a linking initiator are large in size and difficult to cause diffusion. However, by passing the radicals to a small chain transfer agent, the radicals become active radicals rich in diffusibility, and the polymerization rate is greatly increased. be able to.

  Examples of co-sensitizers include amines such as M.I. R. Sander et al., “Journal of Polymer Society”, Vol. 10, 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, Japanese Patent Publication No. 59-138205. No. 60-84305, JP-A 62-18537, JP-A 64-33104, Research Disclosure 33825, and the like. Specific examples include triethanolamine. P-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

  Other examples of co-sensitizers include thiols and sulfides such as thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142772, No. 56-75643, such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercapto. And naphthalene.

  Other examples of co-sensitizers include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in JP-B-48-42965 (eg, tributyltin acetate), and JP-B-55-34414. And a hydrogen compound described in JP-A-6-308727 (eg, trithiane).

Examples of other co-sensitizers include the following.
(A) Compound that is reduced to produce an active radical Compound having a carbon-halogen bond: It is considered that an active radical is generated by reductive cleavage of the carbon-halogen bond. 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 the 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.

  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: those 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 oximes obtained by reacting these with hydroxyamines and then etherifying N—OH Mention may be made of ethers.

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

(B) Compounds that react with radicals to convert to 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. Specifically, 2-mercaptobenzimidazoles etc. are mentioned, for example.

  More specific examples of these co-sensitizers are described, for example, in JP-A-9-236913 as additives for the purpose of improving sensitivity. Some examples are shown below, but those used for the photosensitive layer of the lithographic printing plate precursor according to the invention are not limited thereto. In the following exemplary compounds, Ph represents a phenyl group, TMS represents a trimethylsilyl group, and Me represents a methyl group.

  In the present invention, the co-sensitizer is at least one compound selected from the group consisting of thiol compounds, sulfide compounds, amino compounds, amino acid compounds, trichloromethyl compounds, onium salt compounds, and oxime compounds. Is preferred.

In the photopolymerizable composition of the present invention, it is particularly preferable to use a thiol compound (for example, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, etc.) as a co-sensitizer.
Especially, the thiol compound represented with the following general formula (I) known as a chain transfer agent is used especially suitably.

  In general formula (I), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent. A represents an atomic group that forms a 5-membered or 6-membered heterocycle having a carbon atom together with a —N═C—N— moiety. A may further have a substituent.

  More preferably, those represented by the following general formula (IA) or general formula (IB) are used.

  In general formula (IA) and formula (IB), R represents an alkyl group which may have a substituent or an aryl group which may have a substituent. X represents a halogen atom, an alkoxyl group, an alkyl group which may have a substituent, or an aryl group which may have a substituent.

  Specific examples of the compound represented by formula (I) are shown below, but the present invention is not limited to these.

  The content of the co-sensitizer in the photopolymerizable composition of the present invention is from the viewpoint of improving the curing rate due to the balance between the polymerization growth rate and radical chain transfer, with respect to the total solid mass of the photopolymerizable composition, The range of 0.1-30 mass% is preferable, the range of 1-25 mass% is more preferable, and the range of 0.5-20 mass% is still more preferable.

[Other ingredients]
The photopolymerizable composition of the present invention may contain known additives and the like appropriately selected as other components depending on the purpose within a range that does not impair the effect. Examples of the other components include photopolymerization initiators, oxygen scavengers, thermal polymerization inhibitors, ultraviolet absorbers, fluorescent brighteners, chain transfer agents, antioxidants, and precursors thereof. These are preferably added in an amount of 0.01 to 20% by mass, more preferably 0.2 to 15% by mass based on the total mass of the photopolymerizable composition, and 0.5 to 10% by mass. It is particularly preferred that it is added.

  The photopolymerizable composition of the present invention can also contain a binder for the purpose of adjusting the viscosity. It is particularly convenient when the photopolymerizable composition is a liquid or a viscous material. The content of the binder is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, and most preferably 15 to 85% by mass with respect to the total solid content. The choice of the binder is made depending on the field of application and the properties required for that field, such as developing ability in aqueous or organic solvent systems, adhesion to substrates and sensitivity to oxygen.

  As the binder, a polymer having a weight average molecular weight of about 5,000 to 2,000,000, preferably 10,000 to 1,000,000 is preferable. Such polymers include, for example, acrylate and methacrylate homo- or copolymers (eg, methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, poly (alkyl methacrylate), poly (alkyl acrylate), etc.), cellulose esters or cellulose ethers (eg, , Cellulose acetate, cellulose acetobutyrate, methyl cellulose, ethyl cellulose, etc.), polyvinyl butyral, polyvinyl formal, cyclized rubber, polyether (eg, polyethylene oxide, polypropylene oxide, polytetrahydrofuran), polystyrene, polycarbonate, polyurethane, chlorinated polyolefin , Polyvinyl chloride, vinyl chloride / vinylidene copolymer, vinylidene chloride and acrylonitrile Polymer, methyl methacrylate, vinyl acetate, polyvinyl acetate, copoly (ethylene / vinyl acetate), polycaprolactam, poly (hexamethylene adipamide), polyester (eg poly (ethylene glycol terephthalate), poly (hexamethylene glycol succinate) And the like), polyamide, polyurea and the like.

  Further, water-soluble polymers such as gelatins, (modified) polyvinyl alcohol, polyvinyl pyrrolidone, styrene-maleic acid copolymer hydrolyzate, polystyrene sulfonic acid soda, and alginic acid sodium are also included. Furthermore, latexes such as styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, and methyl acrylate-butadiene rubber latex may be used.

  Unsaturated compounds can also be used as a mixture with non-photopolymerizable film-forming components, such as physically dried polymers, or polymer solutions in organic solvents, such as nitrocellulose or cellulose acetobutyrate. It is done. However, they may be chemically and / or thermally curable (thermosetting) resins such as polyisocyanates, polyepoxides, melamine resins and polyimide precursors. The simultaneous use of thermosetting resins is important for use in systems known as hybrid systems that are photopolymerized in the first stage and cross-linked by thermal post-treatment in the second stage. A binder having a polymerizable group can also be used.

[Polymerization inhibitor]
In the present invention, a small amount of a thermal polymerization inhibitor is added to prevent unnecessary thermal polymerization of a compound having an ethylenically unsaturated double bond that can be polymerized during the production or storage of the photopolymerizable composition. Is preferred.
Examples of the thermal polymerization inhibitor that can be used in the present invention 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-t-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt, cuperon Al 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. If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide may be added to prevent polymerization inhibition due to oxygen, and it may be unevenly distributed on the surface of the photosensitive layer in the course of drying after coating. . 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.

  The light source that can be used for imagewise exposure can be appropriately selected from known light sources having a light source wavelength in the visible to infrared region. Among them, a light source having a maximum absorption wavelength of 300 to 1000 nm is preferable. (Semiconductor) laser light sources or LEDs of blue, green, red, etc. are more preferable in terms of simple downsizing and cost reduction of the device. In order to obtain higher sensitivity, it is preferable to appropriately select a light source having a wavelength suitable for the absorption wavelength of a light absorbing material such as a spectral sensitizing dye. On the other hand, as the light source that can be used for decoloring the photopolymerizable composition and the recording material described later, it is more preferable to appropriately select a light source having a wavelength that matches the absorption wavelength of the photopolymerizable composition. . Specifically, a wide range of light sources such as a mercury lamp, an ultra-high pressure mercury lamp, an electrodeless discharge type mercury lamp, a xenon lamp, a tungsten lamp, a metal halide lamp, a (semiconductor) laser light source, an LED, and a fluorescent lamp are preferable.

A cured film can be formed using the photopolymerizable composition of the present invention.
At that time, as the support to which the photocurable composition is applied, a dimensionally stable plate-like material is used, but the material, shape, surface state and the like are not particularly limited. For example, the dimensionally stable plate-like material includes paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), and aluminum (including aluminum alloy), zinc, copper, etc. Metal plates, and plastic films such as cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc. Examples thereof include paper or plastic film on which a metal as described above is laminated or vapor-deposited.

  In addition, on the layer of the photopolymerizable composition provided on the support, for the purpose of preventing the polymerization inhibiting action due to oxygen in the air, it has excellent oxygen barrier properties such as polyvinyl alcohol and acidic celluloses. It is optional to provide a protective layer made of a polymer.

  The cured film thus obtained is a photocurable paint or coating, a photocurable encapsulant, a photocurable adhesive, ink, a color filter, a hologram recording medium, a lithographic printing, a resin letterpress, a photoresist, a solder resist. It can be used for surface processing of various metals, resins, glass, paper, wood and the like.

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

(Preparation of Photopolymerizable Composition Sample S1 (Invention Example))
The following compounds were mixed to prepare a photopolymerizable composition solution S1.
・ Polymethyl methacrylate 0.49g
(PMMA, made by aldrich)
・ Dipentaerythritol hexaacrylate 0.23g
(DPHA, Shin-Nakamura Chemical Co., Ltd.)
-Photopolymerization initiator DA-1 18.7mg
(2.14 × 10 ^-2 mmole)
・ 2-Mercaptobenzoxazole (MBO) 32.4mg
(2.14 × 10 ⁻¹ mmole)
・ Methyl ethyl ketone 3.0g
・ 0.4g of 1-methoxy-2-propanol

  When the absorption coefficient and the maximum absorption wavelength in tetrahydrofuran were measured for the photopolymerization initiator compound DA-1 using a UV measuring device (manufactured by Shimadzu Corporation, UV-3600, trade name), the absorption coefficient was 11.3. The maximum absorption wavelength was 432 nm.

(Preparation of Photopolymerizable Composition Sample S2 (Comparative Example))
In the preparation of the sample S1, the photopolymerization initiator DA-1 was replaced with the compound D1 8.4 mg and the compound A1 11.3 mg (both 2.14 × 10 ⁻² mmole). Photopolymerizable composition solution S2 was prepared. Here, the compounds D1 and A1 are compounds each having the light absorption part D or the active part A in the photopolymerization initiator DA-1 used in the sample S1.

(Preparation of Photopolymerizable Composition Sample S3 (Comparative Example))
In the preparation of sample S1, a photopolymerizable composition solution S3 was prepared in the same manner as sample S1, except that 2-mercaptobenzoxazole (MBO) was not added.

(Preparation of Photopolymerizable Composition Sample S4 (Comparative Example))
In the preparation of sample S2, a photopolymerizable composition solution S4 was prepared in the same manner as sample S2, except that 2-mercaptobenzoxazole (MBO) was not added.

(Production of cured film)
The prepared photopolymerizable composition solutions S1 to S4 were each applied on a silicon substrate using a spin coater and dried for 3 minutes to obtain a coating film having a thickness of 3 μm.
Separately, in order to obtain the concentration of the coating film, it was applied to the glass substrate under the same conditions and the absorption was measured. As a result, the absorbance at 440 nm for all the samples S1 to S4 was 0.8.

A cured film was prepared by irradiating each coating film with light having passed through a filter having a wavelength of 440 nm using a light irradiation apparatus (trade name, EXECULE 3000, manufactured by HOYA). At this time, the irradiation intensity of 440 nm light is 1.5 mW.
At this time, light exposure was performed at an exposure amount of 50.00 mJ / cm ² , 100.00 mJ / cm ² , 150.00 mJ / cm ² , and 200.00 mJ / cm ^2. The polymerization rate (Conversion) of S4 was measured by following the disappearance of the double bond of the monomer, that is, the decrease in absorption at 1430-1400 cm ⁻¹ by FT-IR. As the FT-IR apparatus, NICOLET6700 (manufactured by Thermo Electron, trade name) was used. The results are shown in Table 1. Table 2 shows the results of comparing the samples S1 and S2 containing the co-sensitizer with the samples S3 and S4 not containing the co-sensitizer, respectively.

As is apparent from the results in Table 1, the sample S1 of the present invention has a remarkably large double bond consumption rate as compared with Comparative Samples S2 to S4 at any exposure amount, and exhibits excellent polymerization reactivity. I understood.
As is clear from the results in Table 2, the consumption rate of double bonds can be obtained by including a co-sensitizer in the comparative sample S2 using the compounds D1 and A1 having the light absorption part D or the active part A. However, in the sample S1 of the present invention containing the photopolymerization initiator (linkage initiator) represented by the general formula (1), it was found that the consumption rate of double bonds further increased. From this, the photopolymerizable composition of the present invention containing the radical polymerization initiator and the co-sensitizer in which the light absorption part D and the radical generation part A are connected has particularly high sensitivity and excellent polymerization. It was found to show sex.

Claims (4)

A photopolymerizable composition comprising a polymerizable compound having an ethylenically unsaturated bond, a radical generator represented by the following general formula (1), and a co-sensitizer.
General formula (1) D-LA
(In the formula, D represents a light absorbing part having an absorption coefficient of 1000 or more in a wavelength region longer than 300 nm, and A represents an active part that interacts with the photoexcited light absorbing part D to generate radicals. , L represents a linking group for linking the light absorbing part D and the active part A.)   The co-sensitizer is at least one compound selected from the group consisting of thiol compounds, sulfide compounds, amino compounds, amino acid compounds, trichloromethyl compounds, onium salt compounds, and oxime compounds. The photopolymerizable composition according to claim 1.   The photopolymerizable composition according to claim 1 or 2, wherein the co-sensitizer is contained in an amount of 0.5 to 20% by mass based on the total solid content of the photopolymerizable composition.   The light absorbing part D in the general formula (1) contains a cyanine dye, a hemicyanine dye, a merocyanine dye, a coumarin dye, or a hemioxonol dye, according to any one of claims 1 to 3. Photopolymerizable composition.