JP2005350559A - Ink composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition maintaining the radiation curing rate and scarcely solidifying an ink sticking to an ink-jet nozzle. <P>SOLUTION: The ink composition comprises at least a polymerizable compound, a colorant, a polymerization initiator and a precursor compound of an ultraviolet light absorber. In the ink composition, the precursor of the ultraviolet light absorber is preferably a compound having no UV absorption ability before light irradiation by the presence of a protective group such as a benzenesulfonyl group but removing the protective group by light irradiation and converted into a UV absorber having the UV absorption ability by the light irradiation. The ink composition is the ink composition for ink-jets. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink composition containing a polymerizable compound, a colorant, a photopolymerization initiator, and an ultraviolet absorber precursor compound, and further relates to an ink jet recording method for printing the ink composition.

  A water-based ink composition has poor water resistance when printed on plain paper, and is likely to bleed. In addition, when printed on a non-water-absorbing recording material such as plastic, adhesion of ink droplets is poor. For this reason, image formation could not be performed, and drying of the solvent was extremely slow, so that it was necessary to dry without overlapping the recorded material immediately after printing, and the image was liable to blur.

  As a material suitable for printing on a non-water-absorbing recording material, Patent Document 1 discloses an ultraviolet curable ink using a polyfunctional monomer having excellent adhesion to the recording material. This ink was slow to dry and was insufficient to form a full color image. In order to solve the drying property, a method using a volatile organic solvent as the solvent of the ink has been carried out, but in order to dry quickly, it is highly flammable, such as methyl ethyl ketone and ethanol, and is also highly volatile. It was necessary to use a solvent as the main component.

  Patent Document 2 discloses an inkjet ink that is cured and fixed by radiation rather than volatilization of the ink solvent. However, since the pigment dispersion is used as the coloring component, the nozzles are clogged due to the aggregation of the pigment, and it is difficult to discharge the ink stably.

  On the other hand, when a pigment is used as the colorant, the transparency is inferior and the color tone is insufficient, so that it is difficult to obtain a photographic image quality. As a means for solving the problem, an ultraviolet curable ink using a dye as a colorant is disclosed in Patent Document 3, but an undesirable polymerization reaction is likely to occur during storage of the ink, and storage stability is not sufficient. The problem was. Furthermore, since conductive salts are contained and the solubility in these inks may be poor, there is a concern of poor printing due to precipitation in a long-term storage state.

In order to solve these problems, ultraviolet curable inks described in Patent Document 4, Patent Document 5, and Patent Document 6 have been developed.
In Patent Document 4, an ultraviolet curable ink containing a polymerizable compound and an oil-soluble dye having a diazo moiety was developed, and an inkjet ink excellent in storage stability was provided.
In Patent Document 5, an ultraviolet curable ink containing a polymerizable compound and an oil-soluble dye that is a phthalocyanine compound was developed, and an ink-jet ink excellent in storage stability was provided.
In Patent Document 6, an ultraviolet curable ink containing a polymerizable compound, an oil-soluble dye, and a storage stabilizer was developed, and an inkjet ink excellent in storage stability was provided.
However, in the above ultraviolet curable ink, the ultraviolet light for curing the ink ejected on the recording material is irregularly reflected by the recording material and reaches the inkjet nozzle, so that the ink adhering to the nozzle is photocured and drops. It had the disadvantage of being difficult.

  On the other hand, in the heat-sensitive recording material described in Patent Document 7, when the heat-sensitive recording material is exposed to sunlight for a long time or posted for a long time in an office or the like, the background portion is colored by light, There was a defect that the image portion was discolored or faded. In order to solve this problem, a heat-sensitive recording material excellent in light resistance using an ultraviolet absorber precursor compound is provided.

JP-T-2001-512777 Japanese Patent Laid-Open No. 5-214279 U.S. Pat. No. 4,303,924 JP 2003-221528 A JP 2003-221532 A JP 2003-221530 A JP 7-276808 A

  An object of the present invention is to provide an ink composition that maintains the radiation curing rate and is difficult to solidify the ink attached to the inkjet nozzle.

The above-described problems of the present invention have been solved by the following means.
1. An ink composition containing at least a polymerizable compound, a colorant, a photopolymerization initiator, and an ultraviolet absorber precursor compound.
2. 2. The ink composition according to 1 above, wherein the ultraviolet absorber precursor is represented by any one of formulas (1) to (4).

上記式（１）中、ｍは１または２を表す。
Ａは、式（１）においてｍ＝１のとき、及び、式（２）〜（４）において、−ＳＯ₂Ｒ、−ＣＯＲ、−ＣＯ₂Ｒ、−ＣＯＮＨＲ、−ＰＯＲ₁Ｒ₂、−ＣＨ₂Ｒ₃または−ＳｉＲ₄Ｒ₅Ｒ₆を表し、Ｒはアルキル基またはアリール基を表し、Ｒ₁及びＲ₂はアルコキシ基、アリールオキシ基、アルキル基またはアリール基を表し、Ｒ₃はニトロ基またはメトキシ基の少なくとも１つが置換したフェニル基を、Ｒ₄、Ｒ₅及びＲ₆はアルキル基またはアリール基を表す。
Ａは、式（１）においてｍ＝２のとき、−ＳＯ₂Ｒ₇ＳＯ₂−、−ＣＯ−、−ＣＯＣＯ−、−ＣＯＲ₇ＣＯ−、−ＳＯ₂−または−ＳＯ−を表し、Ｒ₇はアルキレン基またはアリーレン基を表す。
Ｘは、式（１）、（３）、（４）において、水素原子、アルキル基、アルコキシ基、アリール基またはハロゲン原子を表し、式（２）において、アルキレン基、−ＯＲ₇Ｏ−または−ＯＣＯＲ₇ＣＯ₂−を表す。
Ｗは、式（１）、（２）、（４）において、水素原子、アルキル基、アルコキシ基、アリール基またはハロゲン原子を表し、式（３）において、−ＯＲ₇Ｏ−または−ＯＣＯＲ₇ＣＯ₂−を表す。
Ｙは、式（１）、（２）、（３）において、水素原子、アルキル基、アルコキシ基、アリール基またはハロゲン原子を表し、式（４）において、−ＯＲ₇Ｏ−、−ＯＣＯＲ₇ＣＯ₂−、−ＣＨ₂ＣＨ₂ＣＯ₂Ｒ₇ＯＣＯＣＨ₂ＣＨ₂−、−ＣＨ₂ＣＨ₂ＯＣＯＲ₇ＣＯ₂ＣＨ₂ＣＨ₂−または−ＣＨ₂ＣＨ₂ＣＯＮ（Ｒ₈）Ｒ₇Ｎ（Ｒ₈）ＣＯＣＨ₂ＣＨ₂−を表し、Ｒ₈は水素原子またはアルキル基を表す。
Ｚは水素原子、ハロゲン原子、アルキル基またはアルコキシ基を表す。
３．着色剤が油溶性染料である上記１又は２に記載のインク組成物。
４．油溶性染料の酸化電位が１．０Ｖ（ｖｓ ＳＣＥ）以上である上記１〜３記載のインク組成物。
５．インクジェット用インク組成物である上記１〜４いずれか１つに記載のインク組成物。
６．上記１〜５いずれか１つに記載のインク組成物をインクジェットプリンターにより被記録材に印字する工程、及び、活性放射線で重合性化合物を重合させることによりインク組成物を硬化する工程を含むことを特徴とするインクジェット記録方法。

In the above formula (1), m represents 1 or 2.
A represents —SO ₂ R, —COR, —CO ₂ R, —CONHR, —POR ₁ R ₂ , —CH when m = 1 in Formula (1) and in Formulas (2) to (4). ₂ R ₃ or —SiR ₄ R ₅ R ₆ , R represents an alkyl group or an aryl group, R ₁ and R ₂ represent an alkoxy group, an aryloxy group, an alkyl group or an aryl group, and R ₃ represents a nitro group Alternatively, a phenyl group substituted with at least one of methoxy groups, R ₄ , R ₅ and R ₆ each represents an alkyl group or an aryl group.
A represents —SO ₂ R ₇ SO ₂ —, —CO—, —COCO—, —COR ₇ CO—, —SO ₂ — or —SO— when m = 2 in the formula (1), and R ₇ Represents an alkylene group or an arylene group.
X represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in the formulas (1), (3), and (4). In the formula (2), X represents an alkylene group, —OR ₇ O—, or — OCOR ₇ CO ₂ — is represented.
W represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in the formulas (1), (2), and (4). In the formula (3), W represents —OR ₇ O— or —OCOR ₇ CO ₂ represents-.
Y represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in formulas (1), (2), and (3). In formula (4), Y represents —OR ₇ O—, —OCOR ₇ CO _2- , —CH ₂ CH ₂ CO ₂ R ₇ OCOCH ₂ CH ₂ —, —CH ₂ CH ₂ OCOR ₇ CO ₂ CH ₂ CH ₂ — or —CH ₂ CH ₂ CON (R ₈ ) R ₇ N (R ₈ ) COCH ₂ CH ₂ — is represented, and R ₈ represents a hydrogen atom or an alkyl group.
Z represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.
3. 3. The ink composition according to 1 or 2 above, wherein the colorant is an oil-soluble dye.
4). 4. The ink composition according to any one of 1 to 3 above, wherein the oxidation potential of the oil-soluble dye is 1.0 V (vs SCE) or more.
5). 5. The ink composition as described in any one of 1 to 4 above, which is an inkjet ink composition.
6). Including a step of printing the ink composition according to any one of 1 to 5 on a recording material by an ink jet printer, and a step of curing the ink composition by polymerizing a polymerizable compound with actinic radiation. An ink jet recording method.

  According to the present invention, an ink composition was obtained in which the ink adhering to the ink jet nozzle hardly solidifies while maintaining the radiation curing rate.

(Ink composition)
The ink composition used in the present invention will be described in detail.
The ink composition of the present invention is an ink composition (a radiation curable ink composition) that is cured by irradiation with radiation, and contains a polymerizable compound, a colorant, a photopolymerization initiator, and an ultraviolet absorption precursor. Furthermore, you may contain the other component suitably selected as needed.

(Polymerizable compound)
As the polymerizable compound that can be used in the present invention, a compound in which addition polymerization or ring-opening polymerization is initiated by a radical species or a cationic species generated from a photopolymerization initiator by ultraviolet irradiation to produce a polymer is preferably used. Examples of the polymerization mode of addition polymerization include radical, cation, anion, metathesis, and coordination polymerization. Examples of the ring-opening polymerization method include cation, anion, radical, metathesis, and coordination polymerization.
As the polymerization mode of the present invention, radical polymerization is preferably used, but it can also be used in combination with a polymerizable compound that is cured by another polymerization mode. As the polymerizable compound, a compound that undergoes addition polymerization in particular by radical polymerization can be preferably used.

Examples of the addition polymerizable compound include compounds having at least one ethylenically unsaturated double bond. As the addition polymerizable compound, a compound having at least one, preferably two or more terminal ethylenically unsaturated bonds can be preferably used. Such terminal ethylenically unsaturated compounds are widely known in the industrial field. In the present invention, the binder composition can be used without particular limitation as long as it can be stably ejected from an inkjet nozzle.
The ethylenically unsaturated polymerizable compound has a chemical form of a monofunctional polymerizable compound and a polyfunctional polymerizable compound (ie, bifunctional, trifunctional and 4-6 functional), or a mixture thereof. Examples of the monofunctional polymerizable compound include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters thereof, and amides. As the polyfunctional polymerizable compound, 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.

  Also, addition reaction products, monofunctional or polyfunctional unsaturated carboxylic acid esters or amides having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group and the like with monofunctional or polyfunctional isocyanates and epoxies. A dehydration condensation reaction product with a functional carboxylic acid can also be used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, and a halogen group A substitution reaction product of an unsaturated carboxylic acid ester or amide having a detachable substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol can also be used.

  As a specific example of the radical polymerizable compound which is an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, a (meth) acrylic acid ester is representative, and at least one kind of a trifunctional or higher functional (meth) acrylate is used. , And at least one of monofunctional and / or bifunctional (meth) acrylates is preferably used.

  Specific examples of monofunctional (meth) acrylates include tolyloxyethyl (meth) acrylate, phenyloxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, isobornyl (meth) Examples thereof include acrylate and tetrahydrofurfuryl (meth) acrylate.

  Specific examples of the bifunctional (meth) acrylate include ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, Propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,4-cyclohexanediol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, Mention may be made of pentaerythritol di (meth) acrylate and dipentaerythritol di (meth) acrylate.

  Specific examples of trifunctional (meth) acrylates include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane alkylene oxide modified tri (meth) acrylate, pentaerythritol tri (meth) acrylate , Dipentaerythritol tri (meth) acrylate, trimethylolpropane tri ((meth) acryloyloxypropyl) ether, isocyanuric acid alkylene oxide modified tri (meth) acrylate, propionate dipentaerythritol tri (meth) acrylate, tri ((meta ) Acryloyloxyethyl) isocyanurate, hydroxypivalaldehyde modified dimethylolpropane tri (meth) acrylate, sorbitol tri (meth) acrylate Mention may be made of the rate.

  Specific examples of tetrafunctional (meth) acrylates include pentaerythritol tetra (meth) acrylate, sorbitol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate propionate, ethoxylated penta Mention may be made of erythritol tetra (meth) acrylate.

  Specific examples of the pentafunctional (meth) acrylate include sorbitol penta (meth) acrylate and dipentaerythritol penta (meth) acrylate.

  Specific examples of hexafunctional (meth) acrylate include dipentaerythritol hexa (meth) acrylate, sorbitol hexa (meth) acrylate, phosphazene alkylene oxide modified hexa (meth) acrylate, captolactone modified dipentaerythritol hexa (meth) acrylate Can be mentioned.

  Here, the above notation of (meth) acrylate is an abbreviated notation indicating that it can have both a methacrylate structure and an acrylate structure.

  Radical polymerizable compounds that are esters of various unsaturated carboxylic acids and aliphatic alcohol compounds are commercially available, PEG600 diacrylate (EB11: manufactured by Daicel UCB), KAYARAD DPCA-60 (caprolactone-modified dipentaerythritol hexa). Acrylate: manufactured by Nippon Kayaku Co., Ltd.) and SR-494 (ethoxylated pentaerythritol tetraacrylate: manufactured by Sartomer).

  In the present invention, the polymerizable compound preferably contains at least one functional (meth) acrylate. Moreover, it is preferable that a polymeric compound contains (a) at least 1 sort (s) of trifunctional or more than (meth) acrylate, and (b) at least 1 sort (s) of monofunctional and / or bifunctional (meth) acrylate. Further, (a) the trifunctional or higher functional (meth) acrylate is more preferably a tetrafunctional, pentafunctional or hexafunctional (meth) acrylate.

In addition to (meth) acrylate, itaconic acid ester, crotonic acid ester, isocrotonic acid ester, maleic acid ester and the like can also be used as the polymerizable compound.
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, and JP-A-59-5240. Those having an aromatic skeleton as described in JP-A-59-5241 and JP-A-2-226149, those containing an amino group as described in JP-A-1-165613, and the like can also be used.

  Specific examples of amide monomers of unsaturated carboxylic acid and aliphatic polyvalent amine compound 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 vinylurethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following formula (5) to a polyisocyanate compound having two or more isocyanate groups. Etc.
Formula (5)
^{_{CH 2 = C (R 1)}} COOCH 2 CH (R 2) OH
(However, R ¹ and R ² represent H or CH _3. )

  In the present invention, a cationic ring-opening polymerizable compound having at least one cyclic ether group such as an epoxy group and / or an oxetane group in the molecule can be used as an ultraviolet curable binder together with an ultraviolet cationic polymerization initiator. .

The general cationic polymerizable compounds preferably used in the present invention will be described below. Examples of the cationic polymerizable compound include curable compounds containing a ring-opening polymerizable group, and among them, a heterocyclic group-containing curable compound is preferable. Examples of such a curable compound include epoxy derivatives, oxetane derivatives, tetrahydrofuran derivatives, cyclic lactone derivatives, cyclic carbonate derivatives, cyclic imino ethers such as oxazoline derivatives, vinyl ethers, etc., and particularly epoxy derivatives, oxetane derivatives, and vinyl ethers. preferable.
Examples of preferable epoxy derivatives are roughly classified into monofunctional glycidyl ethers, polyfunctional glycidyl ethers, monofunctional alicyclic epoxies, polyfunctional alicyclic epoxies, and the like.

  Specific examples of monofunctional and polyfunctional glycidyl ethers include diglycidyl ethers (for example, ethylene glycol diglycidyl ether, bisphenol A diglycidyl ether), trifunctional or higher glycidyl ethers (trimethylolethane triglycidyl ether) , Trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, triglycidyl trishydroxyethyl isocyanurate, etc.), tetra- or higher functional glycidyl ethers (sorbitol tetraglycidyl ether, pentaerythritol tetraglycyl ether, polyglycidyl ether of cresol novolac resin, Phenol novolac resin polyglycidyl ether, etc.), alicyclic epoxies (Celoxide 2021P, Celoxy Id 2081, epolide GT-301, epolide GT-401 (manufactured by Daicel Chemical Industries, Ltd.), EHPE (manufactured by Daicel Chemical Industries, Ltd.), phenol novolac resin polycyclohexyl epoxy methyl ether, etc.), oxetanes (OX-SQ, PNOX-1009 (manufactured by Toagosei Co., Ltd.)) and the like are included, but the present invention is not limited to these.

In the present invention, an alicyclic epoxy derivative can be preferably used. The “alicyclic epoxy group” refers to a partial structure obtained by epoxidizing a double bond of a cycloalkene ring such as a cyclopentene group or a cyclohexene group with an appropriate oxidizing agent such as hydrogen peroxide or peracid.
The alicyclic epoxy compound is preferably a polyfunctional alicyclic epoxy having two or more cyclohexene oxide groups or cyclopentene oxide groups in one molecule. Specific examples of the monofunctional or polyfunctional alicyclic epoxy compound include 4-vinylcyclohexene dioxide, (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate, and di (3,4-epoxy). Cyclohexyl) adipate, di (3,4-epoxycyclohexylmethyl) adipate, bis (2,3-epoxycyclopentyl) ether, di (2,3-epoxy-6-methylcyclohexylmethyl) adipate, dicyclopentadiene dioxide It is done.
One type of alicyclic epoxy compound may be used, or a mixture of two or more types may be used.
Various alicyclic epoxy compounds are commercially available and can be obtained from Union Carbide Japan Co., Ltd., Daicel Chemical Industries, Ltd., and the like.

The glycidyl compound which has a normal epoxy group which does not have an alicyclic structure in a molecule | numerator can be used independently, or it can also use together with said alicyclic epoxy compound.
Examples of such normal glycidyl compounds include glycidyl ether compounds and glycidyl ester compounds, but it is preferable to use glycidyl ether compounds in combination.
Specific examples of the glycidyl ether compound include 1,3-bis (2,3-epoxypropyloxy) benzene, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy. Resin, aromatic glycidyl ether compound such as trisphenol methane type epoxy resin, aliphatic glycidyl ether compound such as 1,4-butanediol glycidyl ether, glycerol triglycidyl ether, propylene glycol diglycidyl ether, trimethylolpropane tritriglycidyl ether Can be mentioned. Examples of the glycidyl ester include glycidyl ester of linolenic acid dimer.
Glycidyl ethers can be obtained commercially from Yuka Shell Epoxy Co., Ltd.

  In the present invention, a compound having an oxetanyl group which is a 4-membered cyclic ether (hereinafter, also simply referred to as “oxetane compound”) can be used. An oxetanyl group-containing compound is a compound having one or more oxetanyl groups in one molecule. This oxetanyl group-containing compound is roughly classified into a monofunctional oxetane compound having one oxetanyl group in one molecule and a polyfunctional oxetane compound having two or more oxetanyl groups in one molecule.

  As the monofunctional oxetane compound, a compound represented by the following formula (6) is preferable.

式（６）中、Ｒ₁はメチル基又はエチル基を示す。Ｒ₂は、炭素数６ないし１２の炭化水素基を示す。
Ｒ₂の炭化水素基としては、フェニル基やベンジル基も採りうるが、炭素数６ないし８のアルキル基が好ましく、２−エチルへキシル基等の分岐アルキル基が特に好ましい。Ｒ₂がフェニル基であるオキセタン化合物の例は、特開平１１−１４０２７９号公報に記載されている。Ｒ₂が置換されていても良い、ベンジル基であるオキセタン化合物の例は、特開平６−１６８０４号公報に記載されている。

In the formula (6), R ₁ represents a methyl group or an ethyl group. R ₂ represents a hydrocarbon group having 6 to 12 carbon atoms.
The hydrocarbon group for R ₂ may be a phenyl group or a benzyl group, but is preferably an alkyl group having 6 to 8 carbon atoms, particularly preferably a branched alkyl group such as a 2-ethylhexyl group. Examples of oxetane compounds in which R ₂ is a phenyl group are described in JP-A No. 11-140279. An example of an oxetane compound which is a benzyl group, in which R ₂ may be substituted, is described in JP-A-6-16804.

  In the present invention, a polyfunctional oxetane compound can be used, but a preferred compound group is represented by the following formula (7).

式（７）中、ｍは２、３又は４の自然数を示し、Ｚは酸素原子、硫黄原子、又はセレン原子を表す。Ｒ₃は水素原子、フッ素原子、炭素数が１ないし６の直鎖もしくは分岐状のアルキル基、炭素数が１ないし６のフルオロアルキル、アリル基、フェニル基又はフリル基である。Ｒ₄は、ｍ価の連結基であり、炭素数が１ないし２０の基であることが好ましく、１個以上の酸素原子、硫黄原子を含んでいても良い。
Ｚは酸素原子が好ましく、Ｒ₃はエチル基が好ましく、ｍは２が好ましく、Ｒ₄としては、炭素数が１ないし１６の線形又は分岐アルキレン基、線形又は分岐ポリ（アルキレンオキシ）基が好ましく、Ｒ₃、Ｒ₄、Ｚ及びｍに対する好ましい例の内から任意の２つ以上を組み合わせた化合物は更に好ましい。

In formula (7), m represents a natural number of 2, 3 or 4, and Z represents an oxygen atom, a sulfur atom or a selenium atom. R ₃ is a hydrogen atom, a fluorine atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a fluoroalkyl having 1 to 6 carbon atoms, an allyl group, a phenyl group or a furyl group. R ₄ is an m-valent linking group, preferably a group having 1 to 20 carbon atoms, and may contain one or more oxygen atoms and sulfur atoms.
Z is preferably an oxygen atom, R ₃ is preferably an ethyl group, m is preferably 2, and R ₄ is preferably a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched poly (alkyleneoxy) group. , R ₃ , R ₄ , Z and m are more preferably compounds obtained by combining any two or more of the preferred examples.

  As the ultraviolet curable binder of the present invention, it is also preferable to use a radical polymerizable ethylenically unsaturated compound and a cationic polymerizable cyclic ether (epoxy derivative and / or oxetane derivative) in combination. There is an advantage that a bonded body having balanced physical properties can be obtained due to the structure of an interpenetrating polymer network (IPN). In this case, it is preferable to use a radical photopolymerization initiator and a cationic photopolymerization initiator (such as an onium salt) in combination as the photopolymerization initiator.

The volatile component after curing of the ultraviolet curable binder is preferably 5% by weight or less. For this reason, it is preferable to use a solvent-free formulation that does not use an organic solvent for the binder.
In order to reduce the volatile components after curing, the remaining uncured polymerizable compound can be post-polymerized by ultraviolet irradiation or heating.

  In the present invention, gamma rays, alpha rays, X rays, ultraviolet rays, visible rays, electron beams and the like can be used as radiation for causing polymerization of the polymerizable compound to proceed. Of these, ultraviolet rays and visible rays are preferably used from the viewpoint of cost and safety, and ultraviolet rays are more preferably used.

(Polymer compound for viscosity adjustment)
As the polymerizable compound for adjusting viscosity, a compound having a low viscosity and copolymerizable with the polymerizable compound is used. For example, acrylate, methacrylate, acrylamides can be mentioned. Specifically, tolyloxyethyl (meth) acrylate, phenyloxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, ethylene glycol di (meth) acrylate, divinylbenzene, Methylene bisacrylamide, 1,6-di (meth) acryloyloxyhexane, etc., preferably, tolyloxyethyl (meth) acrylate, ethylene glycol di (meth) acrylate, 1,6-di (meth) acryloyloxyhexane, etc. It is done.
In ring-opening polymerizable cyclic ethers, bifunctional or higher cyclic ethers generally have high reactivity but high viscosity. Monofunctional cyclic ethers can be used in combination to adjust the viscosity to low.

(Coloring agent)
Colorants that can be used in the ink composition of the present invention are roughly classified into dyes and pigments, and dyes can be preferably used. The dye is preferably an oil-soluble dye.

<Dye>
By using yellow (Y), magenta (M) and cyan (C) dyes, which are the three primary colors of the subtractive color method, a wide range of hues can be reproduced with different saturations. In this invention, it is preferable to use the dye utilized for the color print of a color photograph. Details are described below.

As yellow dyes, U.S. Pat. Nos. 3,933,501, 4,022,620, 4,326,024, 4,401,752, 4,248,961, JP-B 58- 10739, British Patents 1,425,020, 1,476,760, U.S. Patents 3,973,968, 4,314,023, 4,511,649, European Patent 249,473A No., couplers represented by formulas (I) and (II) of No. 502,424A, couplers represented by formulas (1) and (2) of No. 513,496A (particularly Y-28 on page 18) A coupler represented by formula (I) in claim 1 of US Pat. No. 568,037A, a coupler represented by general formula (I) in columns 45 to 55 of column 1 of US Pat. No. 5,066,576, The general formula (I A coupler described in claim 1 on page 40 of European Patent No. 498,381A1 (particularly D-35 on page 18), a coupler represented by formula (Y) on page 4 of 447,969A1 (Especially Y-1 (page 17), Y-54 (page 41)), couplers represented by formulas (II) to (IV) in columns 7 to 58 of US Pat. No. 4,476,219, column 7. And ketimine type dyes obtained from (particularly II-17, 19 (column 17), II-24 (column 19)). Preferably, dyes described in JP 2001-294773 A, JP 2002-121414 A, JP 2002-105370 A, JP 2003-26974 A, JP 2003-73598 A, and the like are mentioned. Among these, a pyrazole compound represented by the general formula (Y-II) described in JP-A-2003-73598 is more preferably used.
Y-1 shown below can be preferably used as a yellow dye.

Examples of the magenta dye include dyes described in JP-A Nos. 2001-181549, 2002-121414, 2002-105370, 2003-12981, and 2003-26974. It is done.
Of these, a pyrazolotriazole azomethine compound represented by the general formula (III) described in JP-A No. 2002-121414 is preferably used.
M-1 shown below can be preferably used.

Examples of the cyan dye include dyes described in JP-A Nos. 2002-121414, 2002-105370, 2003-3109, and 2003-26974.
A pyrrolotriazole azomethine compound represented by the general formula (IV-1a) and a phthalocyanine compound represented by the general formulas (C-II-1) and (C-II-2) described in JP-A No. 2002-121414 are disclosed. Preferably used.
C-1 shown below can be preferably used as a cyan dye.

  If necessary, a black (black) dye may be used in combination with the three primary colors of CMY. The black dye can be made by mixing CMY3 dye.

As dyes other than those described above, those generally used in the technical field of printing (for example, color materials for copying or color proofing plates such as printing ink, thermal ink jet recording, and electrophotographic recording) can be used.
For example, “Organization of Organic Synthetic Chemistry” “Dye Handbook” Maruzen Co., Ltd. (published in 1970), Sadaharu Abeda, Kunihiko Imada “Commentary Dye Chemistry” Co., Ltd. Examples include dyes described in Kodansha (1986), Chemicals for Inkjet Printers-Material Development Trends and Perspective Survey-"CMC Co., Ltd. (1997), Takeshi Amari" Inkjet Printers-Technology and Materials ", etc. It is done.

<Oxidation potential>
In the present invention, it is preferable to use an oil-soluble dye having an oxidation potential nobler than 1.0 V (vs SCE). The oxidation potential is preferably as noble, more preferably noble than the oxidation potential of 1.1 V (vs SCE), and most preferably nob of 1.2 V (vs SCE).

  A person skilled in the art can easily measure the value (Eox) of the oxidation potential. Regarding this method, see, for example, P.I. Delahay, “New Instrumental Methods in Electrochemistry” (1954, published by Interscience Publishers) J. et al. "Electrochemical Methods" by Bard et al. (1980, published by John Wiley & Sons) and "Electrochemical Measurement Methods" by Akira Fujishima et al. (Published by Gihodo Publishing Co., 1984).

Specifically, the oxidation potential is 1 × 10 ⁻⁴ to 1 × 10 ⁻⁶ mol / in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate. Approximate the oxidization wave in a straight line by dissolving 1 liter and sweeping to the oxidation side (noble side) using carbon (GC) as the working electrode and rotating platinum electrode as the counter electrode by cyclic voltammetry and DC polarography equipment The intermediate potential of the line formed by the intersection of this straight line and the residual current / potential line and the intersection of the straight line and the saturation current line (or the intersection of the straight line parallel to the vertical axis passing through the peak potential value) Values are measured as values for SCE (saturated calomel electrode). Although this value may be deviated by several tens of mil volts due to the influence of the liquid potential difference or the liquid resistance of the sample solution, the reproducibility of the potential can be ensured by inserting a standard sample (for example, hydroquinone). The supporting electrolyte and solvent to be used can be selected appropriately depending on the oxidation potential and solubility of the test sample. The supporting electrolytes and solvents that can be used are described in Akira Fujishima et al., “Electrochemical measurement method” (published by Gihodo Publishing Co., Ltd., 1984), pages 101 to 118.
In the concentration range of the measurement solvent and the phthalocyanine compound sample, the oxidation potential in a non-association state is measured.

The value of Eox represents the ease of transfer of electrons from the sample to the electrode, and the greater the value (the higher the oxidation potential), the less transfer of electrons from the sample to the electrode, in other words, less oxidation.
When a dye having a low oxidation potential is used, polymerization inhibition by the dye is large and curability is lowered. When a dye having a noble oxidation potential is used, there is almost no polymerization inhibition.

<Pigment>
The pigment is not particularly limited, and all commercially available organic and inorganic pigments or pigments dispersed in an insoluble resin or the like as a dispersion medium, or the resin is grafted onto the pigment surface Can be used. Moreover, what dye | stained the resin particle with dye can be used.

Specific examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), Strontium titanate (SrTiO ₃ , so-called titanium strontium white) or the like can be used.

  Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable. Therefore, it has a high hiding power and coloring power as a pigment, and further, acid and alkali. Excellent durability against other environments. Therefore, it is preferable to use titanium oxide as the white pigment. Of course, other white pigments (may be other than the listed white pigments) may be used depending on the type of powder material and binder component.

In the present invention, CMY pigments may be used instead of CMY dyes.
Specific examples of organic pigments and inorganic pigments include, for example, C.I. I. Pigment Yellow 1 (Fast Yellow G etc.), C.I. I. A monoazo pigment such as C.I. Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as C.I. Pigment Yellow 17; I. Non-benzidine type azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Condensed azo pigments such as CI Pigment Yellow 95 (Condensed Azo Yellow GR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (such as quinoline yellow lake); I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.); I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow, etc.).

  As a magenta color, C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Disazo pigments such as C.I. Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Azo lake pigments such as C.I. Pigment Red 57: 1 (Brilliant Carmine 6B); I. Condensed azo pigments such as C.I. Pigment Red 144 (condensed azo red BR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Red 174 (Phloxine B Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G 'lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as C.I. Pigment Red 88 (Thioindigo Bordeaux, etc.); I. Perinone pigments such as C.I. Pigment Red 194 (perinone red, etc.); I. Perylene pigments such as C.I. Pigment Red 149 (perylene scarlet, etc.); I. Quinacridone pigments such as CI Pigment Red 122 (quinacridone magenta, etc.); I. Isoindolinone pigments such as CI Pigment Red 180 (isoindolinone red 2BLT, etc.); I. And alizarin lake pigments such as CI Pigment Red 83 (Mada Lake, etc.).

  As a pigment exhibiting a cyan color, C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Phthalocyanine pigments such as C.I. Pigment Blue 15 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).

  Examples of the black pigment include carbon black and titanium black.

(Photopolymerization initiator)
The photopolymerization initiator used in the present invention refers to a compound that generates active radical species or cation species by applying active light, and initiates and accelerates the polymerization reaction of the binder. Ultraviolet rays are preferred as the active light. In addition, known as active energy rays, gamma rays, alpha rays, electron rays, and the like can be used instead of active rays.

Examples of the polymerization initiator that generates radicals by the action of light are preferably acetophenone compounds, benzoin compounds, benzophenone compounds, thioxanthone compounds, benzyl compounds, acylphosphine oxide compounds, and the like.
Examples of the acetophenone compound include 2,2-diethoxyacetophenone, 2-hydroxymethyl-1-phenylpropan-1-one, 4′-isopropyl-2-hydroxy-2-methyl-propiophenone, 2-hydroxy -2-methyl-propiophenone, p-dimethylaminoacetone, p-tert-butyldichloroacetophenone, p-tert-butyltrichloroacetophenone, p-azidobenzalacetophenone, 1-hydroxycyclohexyl phenyl ketone and the like.
Examples of the benzoin compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-n-propyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, and benzyldimethyl ketal.
Examples of the benzophenone compounds include benzophenone, methyl o-benzoylbenzoate, Michler's ketone, 4,4′-bisdiethylaminobenzophenone, 4,4′-dichlorobenzophenone, and the like.
Examples of the thioxanthone compound include thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and the like.
Examples of the benzyl compound include benzyl and benzyl-β-methoxyethyl acetal. Examples of the acyl phosphine oxide compound include bis (2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl) phosphine oxide, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, and the like.
Since the sulfonium salt and iodonium salt, which are usually used as photocation generators described below, act as radical generators upon irradiation with ultraviolet rays, these may be used alone in the present invention. In addition to a polymerization initiator, a sensitizer may be used for the purpose of increasing sensitivity. Examples of the sensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, and thioxanthone derivatives.

  As a photopolymerization initiator that generates an active cationic species by ultraviolet rays, an onium salt initiator such as an aromatic iodonium salt such as a triarylsulfonium salt or an aromatic iodonium salt such as a diaryliodonium salt is useful. Nonionic initiators such as nitrobenzyl esters can also be used. Among these, aromatic sulfonium salts and the like are preferable because they are thermally relatively stable. In addition, known photopolymerization initiators described in “Organic Materials for Imaging” published by Organic Electronics Materials Research Group (published in 1997), etc. can also be used.

When an aromatic sulfonium salt and an aromatic iodonium salt are used as an onium salt photoinitiator, the counter anions include BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , PF ₆ ⁻ , PF ₆ ⁻ , B (C ₆ F ₅ ) _4- ^{and the} like. As the initiator, PF ₆ salt or SbF ₆ salt of aromatic sulfonium can be preferably used since it has solubility and moderate polymerization activity. In order to improve solubility, one or more alkyl groups or alkoxy groups having 1 to 10 carbon atoms are introduced into the aromatic group, usually phenyl group, of the aromatic group iodonium salt or aromatic sulfonium salt. A chemical structure is preferred.
PF ₆ salt or SbF ₆ salt of aromatic sulfonium salt is commercially available from Union Carbide Japan Co., Ltd. Asahi Denka Kogyo Co., Ltd. also sells PF ₆ salt of aromatic sulfonium under the trade name of Adekaoptomer SP series.
The aromatic sulfonium salt has an absorption up to about 360 nm, and the aromatic iodonium salt has an absorption up to about 320 nm. Therefore, for curing, it is preferable to irradiate ultraviolet rays including the spectral energy in this region.

<Sensitizer>
The sensitizer is not activated by light irradiation alone, but when used together with the photopolymerization initiator, it is more effective than the photopolymerization initiator used alone, and amines are generally used. The addition of amines increases the curing rate, primarily because hydrogen is supplied to the photopolymerization initiator by the action of hydrogen abstraction, and secondly, the generated radicals are combined with oxygen molecules in the atmosphere and are reactive. This is because the amine has an action of trapping oxygen dissolved in the composition.

  Sensitizers include amine compounds (aliphatic amines, amines containing aromatic groups, piperidine, reaction products of epoxy resins and amines, triethanolamine triacrylate, etc.), urea compounds (allylthiourea, o-tolylthiourea, etc.) ), Sulfur compounds (sodium diethyldithiophosphate, soluble salts of aromatic sulfinic acid, etc.), nitrile compounds (N, N-diethyl-p-aminobenzonitrile, etc.), phosphorus compounds (tri-n-butylphosphine, sodium diethyl) Dithiophosphide, etc.), nitrogen compounds (Michler ketone, N-nitrisohydroxylamine derivatives, oxazolidine compounds, tetrahydro-1,3-oxazine compounds, formaldehyde or condensates of acetaldehyde and diamines), chlorine compounds (carbon tetrachloride, Sa chloroethane, etc.), and the like.

  The usage-amount of a sensitizer is 0-10 mass% normally, 0.1-10 mass% is preferable and 0.2-5 mass% is especially preferable. The selection and combination of the photoinitiator and the sensitizer, and the blending ratio may be appropriately selected depending on the ultraviolet curing monomer used and the apparatus used.

(Ultraviolet absorber (UV) precursor)
The ultraviolet absorber precursor used in the present invention is a UV absorber that has no UV absorbing ability before light irradiation due to the presence of a protecting group such as a benzenesulfonyl group, but has a UV absorbing ability when the protecting group is removed by light irradiation. Refers to a compound that is converted to
The usage-amount of UV precursor is 0.1-50 mass% with respect to a polymeric compound, and 1.0-20 mass% is preferable.
As the UV precursor, compounds represented by the following formulas (1) to (4) can be preferably used.

上記式（１）中、ｍは１または２を表す。

In the above formula (1), m represents 1 or 2.

A represents —SO ₂ R, —COR, —CO ₂ R, —CONHR, —POR ₁ R ₂ , —CH when m = 1 in Formula (1) and in Formulas (2) to (4). ₂ R ₃ or —SiR ₄ R ₅ R ₆ , R represents an alkyl group or an aryl group, R ₁ and R ₂ represent an alkoxy group, an aryloxy group, an alkyl group or an aryl group, and R ₃ represents a nitro group Alternatively, a phenyl group substituted with at least one of methoxy groups, R ₄ , R ₅ and R ₆ each represents an alkyl group or an aryl group.
A represents —SO ₂ R ₇ SO ₂ —, —CO—, —COCO—, —COR ₇ CO—, —SO ₂ — or —SO— when m = 2 in the formula (1), and R ₇ Represents an alkylene group or an arylene group.

X represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in the formulas (1), (3), and (4). In the formula (2), X represents an alkylene group, —OR ₇ O—, or — OCOR ₇ CO ₂ — is represented.

W represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in the formulas (1), (2), and (4). In the formula (3), W represents —OR ₇ O— or —OCOR ₇ CO ₂ represents-.

Y represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in formulas (1), (2), and (3). In formula (4), Y represents —OR ₇ O—, —OCOR ₇ CO _2- , —CH ₂ CH ₂ CO ₂ R ₇ OCOCH ₂ CH ₂ —, —CH ₂ CH ₂ OCOR ₇ CO ₂ CH ₂ CH ₂ — or —CH ₂ CH ₂ CON (R ₈ ) R ₇ N (R ₈ ) COCH ₂ CH ₂ — is represented, and R ₈ represents a hydrogen atom or an alkyl group.

  Z represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.

  Of the above substituents, the alkyl group may be linear or branched, and may have an unsaturated bond. Further, these alkyl groups may be substituted with an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aryl group, a hydroxy group, or the like. The aryl group may be further substituted with an alkyl group, an alkoxy group or a halogen atom.

  Of the above substituents, the alkylene group may be linear or branched, and may contain an unsaturated bond, an oxygen atom, a sulfur atom, or a nitrogen atom. The alkylene group may be further substituted with an alkoxy group, a hydroxy group, an aryloxy group, or an aryl group.

  Of the above substituents, the arylene group may be further substituted with an alkyl group, an alkoxy group, a halogen atom, or the like.

  Among the substituents represented by X, Y and W, a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, a fluorine atom, A chlorine atom and a bromine atom are preferable, and a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a phenyl group, or a chlorine atom is particularly preferable.

  Among the substituents represented by Z, a hydrogen atom, a chlorine atom, a fluorine atom, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms are preferable, and among them, a hydrogen atom and a chlorine atom are particularly preferable. An alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms are preferable.

  Among the substituents represented by R, an alkyl group having 1 to 18 carbon atoms and an aryl group having 6 to 18 carbon atoms are preferable, and among them, an alkyl group having 1 to 12 carbon atoms and a carbon atom number of 6 are particularly preferable. ~ 12 aryl groups are preferred.

Among the substituents represented by R ₁ and R ₂ , an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms, and 6 to 6 carbon atoms Twelve aryl groups are preferred.

Of the substituents represented by R ₃ , 2-nitrophenyl group, 3,5-dimethoxyphenyl group, and 3,4,5-trimethoxyphenyl group are preferable.

Of the substituents represented by R ₄ , R ₅ and R ₆ , an alkyl group having 1 to 12 carbon atoms and an aryl group having 6 to 12 carbon atoms are preferable. Among these, an alkyl group having 1 to 8 carbon atoms and a phenyl group are particularly preferable.

In a so-called bis body having two benzotriazole rings in one molecule, the substituent represented by R ₇ is preferably an alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 12 carbon atoms, and R _The substituent represented by ₈ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Of the substituents represented by A, —SO ₂ R is particularly preferable.

  Although the specific example of said substituent is given to the following, this invention is not limited to this. Among the substituents represented by X, Y, and W, as monovalent ones, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, t-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, allyl group, 2-butenyl group, benzyl group, α-dimethylbenzyl group, methoxy group, ethoxy group, propyloxy group, butyloxy group, Octyloxy group, dodecyloxy group, methoxyethoxy group, phenoxyethoxy group, methoxycarbonylethyl group, ethoxycarbonylethyl group, propyloxycarbonylethyl group, butyloxycarbonylethyl group, octyloxycarbonylethyl group, phenoxycarbonylethyl group, phenyl Group, tolyl group, chlorine atom, fluorine atom, bromine source And the like, include the following as divalent.

  Specific examples of the substituent represented by Z include a hydrogen atom, a chlorine atom, a methyl group, an ethyl group, a propyl group, a hexyl group, a methoxy group, an ethoxy group, a propyloxy group, and an octyloxy group.

  Specific examples of the monovalent substituent represented by A include a methanesulfonyl group, an ethanesulfonyl group, a butanesulfonyl group, a benzenesulfonyl group, a 4-methylbenzenesulfonyl group, a 2-mesitylenesulfonyl group, and 4-methoxy. Benzenesulfonyl group, 4-octyloxybenzenesulfonyl group, 2,4,6-triisopropylbenzenesulfonyl group, β-styrenesulfonyl group, vinylbenzenesulfonyl group, 4-chlorobenzenesulfonyl group, 2,5-dichlorobenzenesulfonyl group, 2,4,5-trichlorobenzenesulfonyl group, 1-naphthalenesulfonyl group, 2-naphthalenesulfonyl group, quinolinesulfonyl group, thiophenesulfonyl group, acetyl group, propionyl group, butyryl group, pivaloyl group, lauroyl group, stearoy Group, benzoyl group, cinnamoyl group, furoyl group, nicotinoyl group, methoxycarbonyl group, ethoxycarbonyl group, phenoxycarbonyl group, hexylaminocarbonyl group, phenylaminocarbonyl group, diphenylphosphoryl group, diethylphosphoryl group, 2-nitrobenzyl group, 3,5-dimethoxybenzyl group, 3,4,5-trimethoxybenzyl group, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, diethylisopropylsilyl group, dimethylphenylsilyl group, diphenylmethylsilyl group, triphenyl A silyl group etc. are mentioned, As a bivalent thing, the following are mentioned.

When A is —SiR ₄ R ₅ R _6, a photoacid generator such as an ammonium salt, a diazonium salt, an iodonium salt, a sulfonium salt, a phosphonium salt, or an onium salt may be used in combination for improving photoreactivity. Specific examples of these photoacid generators are detailed in “Organic Materials for Imaging” (edited by Organic Electronics Materials Research Group, 1993).

  Specific examples of the compound represented by the formula (1) of the present invention are shown in the following Tables 1 to 4, but the present invention is not limited thereto. These compounds may be used alone or in combination of two or more.

  The UV precursor compound represented by the formula (1) of the present invention does not absorb the irradiation light when the ink composition is cured, and it is an ultraviolet ray that is irregularly reflected by the recording material with respect to the ink attached to the inkjet nozzle. When light hits, it changes into a UV absorber and absorbs ultraviolet rays, thereby preventing clogging at the ink jet nozzle.

<Hydrogen donor>
In order to increase the conversion efficiency of the UV precursor to the UV absorber, a hydrogen donor can be used in combination. The hydrogen donor can efficiently generate a UV absorber by giving hydrogen to radicals generated from the UV precursor compound by light irradiation. The hydrogen donor preferably does not inhibit the curing reaction, and examples thereof include hydrazide derivatives, phenol derivatives, ascorbic acid derivatives and the like.
In addition, amine compounds, sulfur compounds, nitrile compounds, phosphorus compounds, nitrogen compounds, chlorine compounds, and the like used as the sensitizer can also be used as hydrogen donors.

(UV exposure)
For UV exposure for curing the UV curable binder, generally used xenon flash lamps, LED metal halide lamps, ultra-high pressure mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, deep UV lamps, halogen lamps, etc. can be used. . The exposure wavelength can be 450 to 250 nm, preferably 400 to 300 nm. Irradiation is preferably performed at 5 to 2,000 mW / cm ² .

(Other ingredients)
In the range which does not impair the effect of this invention, the other component suitably selected according to the objective may be included. Examples of the other components include known additives such as a solvent, a polymer, a surface tension adjuster, a storage stabilizer, an antioxidant, a fading inhibitor, a conductive salt, and a pH adjuster.

  The solvent can be used to improve the polarity, viscosity, surface tension, solubility of oil-soluble dyes, conductivity adjustment, and printing performance of the ink. Examples of the solvent include water, a low boiling point organic solvent, and a high boiling point organic solvent. The low boiling point organic solvent is an organic solvent having a boiling point of 100 ° C. or lower. The low-boiling organic solvent is desirably not used in consideration of environmental pollution, but when used, it is preferable to use a highly safe one. A solvent having high safety is a solvent having a high management concentration (an index indicated by a work environment evaluation standard), preferably 100 ppm or more, and more preferably 200 ppm or more. For example, alcohols, ketones, esters, ethers, hydrocarbons and the like can be mentioned. Specific examples include methanol, 2-butanol, acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran and the like. The high boiling organic solvent is an organic solvent having a boiling point higher than 100 ° C. The high-boiling organic solvent preferably has a boiling point of 150 ° C. or higher, more preferably 170 ° C. or higher. Examples include polyhydric alcohols, esters of aliphatic carboxylic acids, phosphoric esters, hydrocarbons, and the like. Specific examples include diethylene glycol, trimethylolpropane, dibutyl phthalate, and 2-ethylhexyl benzoate. And alkylnaphthalene. Depending on the purpose, these can be either liquid or solid at room temperature. The solvent may be used alone or in combination. The amount used in the ink is preferably from 0 to 20% by mass, more preferably from 0 to 10% by mass, and particularly preferably substantially free of ink. The term “substantially free” refers to a case where the material used is other than the main component, that is, contained as an impurity and is not intentionally added.

  The polymer can be used for adjusting the polarity and viscosity of the ink, improving the solubility of the oil-soluble dye, adjusting the adhesion of the cured ink to the recording material, and adjusting the light resistance. The polymer may be dissolved in the ink or may be a fine dispersion, but is preferably dissolved from the viewpoint of the storage stability and ejection performance of the ink. When the polymer is dissolved in the ink, those having high compatibility with dyes and monomers are preferable, and the weight average molecular weight is preferably 50,000 or less, and preferably 20,000 or less from the viewpoint of hardly causing increase in viscosity of the ink. Further preferred is 10,000. For example, vinyl polymer, polyurethane, polyester and the like can be mentioned. Specifically, polybutyl acrylate, poly (isobutyl methacrylate-hydroxyethyl acrylate) (copolymerization mass ratio 95: 5), poly (isopropyl acrylate-tetrahydrofurfuryl acrylate). ) (Copolymerization mass ratio 70:30), poly (butyl methacrylate-N-methoxymethylacrylamide) (copolymerization mass ratio 80:20), polybutylacrylate-polydimethylsiloxane block copolymer (copolymerization mass ratio 90: 10). When the polymer is a fine dispersion, it is essential that the polymer does not substantially dissolve in the monomer, and it is preferable that the polymer does not swell or does not swell. The particle size of the dispersion in the ink is preferably 1 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.1 μm or less. For example, vinyl polymer fine particles, polyurethane fine particles, polyester fine particles, urethane-vinyl composite particles and the like can be mentioned. Specifically, poly (acrylonitrile-ethyl acrylate-ethylene glycol dimethacrylate) (copolymerization mass ratio 60: 37: 3). ), Poly (styrene-butadiene) (copolymerization mass ratio 50:50), and the like. The polymers may be used alone or in combination. The amount used in the ink is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, and particularly preferably 0 to 20% by mass.

  The storage stabilizer is used to suppress undesired polymerization during storage and is used that dissolves in ink. Examples include quaternary ammonium salts, hydroxyamines, cyclic amides, nitriles, substituted ureas, heterocyclic compounds, organic acids, hydroquinones, hydroquinone monoethers, organic phosphines, copper compounds, etc. Specific examples include benzyltrimethylammonium chloride, diethylhydroxylamine, benzothiazole, 4-amino-2,2,6,6-tetramethylpiperidine, citric acid, hydroquinone monobutyl ether, and copper naphthenate. The amount used is preferably 0.005 to 1% by mass, more preferably 0.01 to 0.5% by mass, and particularly preferably 0.01 to 0.2% by mass. Regarding the surface tension adjusting agent, antioxidant, fading preventing agent, and pH adjusting agent, those described in JP-A No. 2001-181549 may be used. The conductive salts must be dissolved in the ink, and examples include potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride, and the like. The preferred physical properties of the ink depend on the printing apparatus, but generally the viscosity is preferably 5 to 100 mPa · s at 25 ° C., more preferably 10 to 80 mPa · s. The surface tension is preferably 20 to 60 mN / m, and more preferably 20 to 40 mN / m.

(Recording material)
Specific examples of the recording material include plain paper, resin-coated paper, ink jet exclusive paper, film, electrophotographic co-paper, fabric, glass, metal, ceramics, and the like. As the recording material, those described in paragraph numbers (0228) to (0246) of JP-A Nos. 2001-181549 and 2001-279141 can be used.

(Inkjet ink composition)
The ink composition of the present invention can be suitably used as an inkjet ink composition, and can be suitably printed on the recording material.

(Inkjet recording method)
The ink jet recording method of the present invention includes a step of printing on a recording material by an ink jet printer and a step of polymerizing a polymerizable compound with actinic radiation.
In the ink jet recording method, recording is performed using an ink composition, but there are no particular limitations on the ink nozzles and the like used at that time, and they can be appropriately selected according to the purpose. As the ink jet recording method, the one described in paragraph number (0247) of JP-A-2001-279141 can be used.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
The materials used in the examples of the present invention are as follows.
KAYARAD DPCA60 (captolactone-modified dipentaerythritol hexaacrylate: manufactured by Nippon Kayaku Co., Ltd.)
HDDA (1,6-hexanediol diacrylate: manufactured by Daicel UC Corporation)
SR-494 (ethoxylated pentaerythritol tetraacrylate: manufactured by Sartomer)
M350 (trimethylolpropane EO-modified triacrylate: manufactured by Toagosei Co., Ltd.)
IBOA (Isobornyl acrylate: manufactured by Daicel UCB)
1-hydroxy-cyclohexyl-phenyl ketone (manufactured by Ciba Specialty Chemicals (Ciba S.C.))
2,4,6-trimethylbenzoylethoxyphenylphosphine oxide (manufactured by Birdish Aniline und Soda Fabric)
Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (manufactured by Birdish Aniline und Soda Fabric)

(Yellow ink)
<Example I-1>
Polymerizable compound: KAYARAD DPCA60 4.0 g
Polymerizable compound: HDDA 16.0 g
N-ethyldiethanolamine 0.3g
Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl ketone 0.3 g
UV precursor: Formula (1), specific example 3 0.5 g
Colorant: Y-1 0.8g
The above components were mixed by stirring to obtain a yellow ink.

<Example I-2>
A yellow ink was obtained in the same manner as in Example I-1, except that Formula (1) Example 21 was used instead of Formula (1) Example 3 of Example I-1 as the UV precursor.

<Comparative Example I-1>
A yellow ink was obtained in the same manner as in Example I-1, except that 0.5 g of the ultraviolet absorber 2- (2-hydroxy-3,5-di-tert-pentylphenyl) benzotriazole was used instead of the UV precursor. It was.

<Comparative Example I-2>
A yellow ink was obtained in the same manner as in Example I-1 except that no UV precursor was used.

(Magenta ink)
<Example II-1>
Polymerizable compound: SR-494 8.4 g
Polymerizable compound: HDDA 11.6 g
Photopolymerization initiator: 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide 0.6 g
UV precursor: Formula (1), specific example 3 0.8 g
p-tert-Butylphenol 0.2g
Colorant: M-1 0.8g
The above components were mixed with stirring to obtain a magenta ink.

<Example II-2>
A magenta ink was obtained in the same manner as in Example II-1, except that Formula (1) Example 23 was used instead of Formula (1) Example 3 of Example II-1 as a UV precursor.

<Comparative Example II-1>
A magenta ink was obtained in the same manner as in Example II-1, except that 0.8 g of the ultraviolet absorber 2- (2-hydroxy-3,5-di-tert-pentylphenyl) benzotriazole was used instead of the UV precursor. It was.

<Comparative Example II-2>
A magenta ink was obtained in the same manner as in Example II-1, except that the UV precursor was not used.

(Cyan ink)
<Example III-1>
Polymerizable compound: M350 10.0 g
Polymerizable compound: IBOA 10.0 g
Photopolymerization initiator: 1.0 g of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide
UV precursor: Formula (1), specific example 7 1.0 g
Coloring agent: C-1 1.0 g
The above components were mixed with stirring to obtain a cyan ink.

<Example III-2>
A cyan ink was obtained in the same manner as in Example III-1, except that Formula (1) Example 21 was used instead of Formula (1) Example 3 of Example III-1 as the UV precursor.

<Comparative Example III-1>
The same procedure as in Example III-1 except that 1.0 g of an ultraviolet absorber 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate was used instead of the UV precursor. Cyan ink was obtained.

<Comparative Example III-2>
A cyan ink was obtained in the same manner as in Example III-1, except that no UV precursor was used.

(Evaluation methods)
The above ink composition was printed on art paper with an ink jet printer (printing speed: 300 dpi, droplet ejection frequency: 2 kHz, number of nozzles: 64), and then 100 mJ / cm with a Deep UV lamp (US-7 SP-7) just below the head. ^The sample was exposed under the condition of energy of ² to obtain print samples having yellow, magenta and cyan densities of 1.0, respectively.
(Curable)
The seal screen was touched with a finger and evaluated in the following three stages.
A thing without stickiness (A)
Somewhat sticky (B)
(C) that there is remarkably stickiness
(Clogged nozzle)
The state of the nozzle after 100 sheets of A4 were printed was observed and evaluated in the following three stages.
No nozzle clogging and good discharge performance (A)
(B) A state where a part of the nozzle is clogged and discharge is defective.
The nozzle is clogged and cannot be discharged at all (C)
The above results are summarized in Table 5.

Claims (6)

  An ink composition containing at least a polymerizable compound, a colorant, a photopolymerization initiator, and an ultraviolet absorber precursor compound. The ink composition according to claim 1, wherein the ultraviolet absorbent precursor is represented by any one of formulas (1) to (4).

In the above formula (1), m represents 1 or 2.
A represents —SO ₂ R, —COR, —CO ₂ R, —CONHR, —POR ₁ R ₂ , —CH when m = 1 in Formula (1) and in Formulas (2) to (4). ₂ R ₃ or —SiR ₄ R ₅ R ₆ , R represents an alkyl group or an aryl group, R ₁ and R ₂ represent an alkoxy group, an aryloxy group, an alkyl group or an aryl group, and R ₃ represents a nitro group Or a phenyl group substituted with at least one of the methoxy groups, R ₄ , R ₅ and R ₆ each represents an alkyl group or an aryl group;
A represents —SO ₂ R ₇ SO ₂ —, —CO—, —COCO—, —COR ₇ CO—, —SO ₂ — or —SO— when m = 2 in the formula (1), and R ₇ Represents an alkylene group or an arylene group.
X represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in the formulas (1), (3), and (4). In the formula (2), X represents an alkylene group, —OR ₇ O—, or — OCOR ₇ CO ₂ — is represented.
W represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in the formulas (1), (2), and (4). In the formula (3), W represents —OR ₇ O— or —OCOR ₇ CO ₂ represents-.
Y represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom in formulas (1), (2), and (3). In formula (4), Y represents —OR ₇ O—, —OCOR ₇ CO _2- , —CH ₂ CH ₂ CO ₂ R ₇ OCOCH ₂ CH ₂ —, —CH ₂ CH ₂ OCOR ₇ CO ₂ CH ₂ CH ₂ — or —CH ₂ CH ₂ CON (R ₈ ) R ₇ N (R ₈ ) COCH ₂ CH ₂ — is represented, and R ₈ represents a hydrogen atom or an alkyl group.
Z represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.   The ink composition according to claim 1 or 2, wherein the colorant is an oil-soluble dye.   The ink composition according to claim 1, wherein the oxidation potential of the oil-soluble dye is 1.0 V (vs SCE) or more.   It is an ink composition for inkjet, The ink composition as described in any one of Claims 1-4. A step of printing on the recording material by an ink jet printer with the ink composition according to any one of claims 1 to 5, and
An ink jet recording method comprising a step of curing an ink composition by polymerizing a polymerizable compound with actinic radiation.