JP5283328B2 - INK COMPOSITION USING CURABLE COMPOSITION AND INK JET RECORDING METHOD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable composition curing by the irradiation of a radiation in a high sensitivity and capable of forming a high strength film, and an ink composition and inkjet-recording method by using the same. <P>SOLUTION: This curable composition comprises a compound having &ge;2 partial structures containing &ge;4-membered ring cyclic ether in its molecule and a partial structure expressed by general formula (1)[wherein, R<SP>1</SP>is an alkylene, a cycloalkylene or an arylene; and (n) is 1 to 8 integer]. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a curable composition suitable as an ink for ink jet recording, an ink composition using the same, and an ink jet recording method using the ink composition.

On the other hand, as an image recording method for forming an image on a recording medium such as paper based on an image data signal, there are an electrophotographic method, a sublimation type and melt type thermal transfer method, an ink jet method and the like. In particular, the ink jet method can be implemented with an inexpensive apparatus, and the ink can be used efficiently because the image is directly formed on the recording medium by ejecting the ink only to the required image portion. Cost is low. Furthermore, there is little noise and it is excellent as an image recording method.
According to the inkjet system, printing is possible not only on plain paper but also on non-water-absorbing recording media such as plastic sheets and metal plates. However, high speed and high image quality are important issues for printing. The time required for drying and curing the droplets after printing has a property of greatly affecting the productivity of printed matter and the sharpness of the printed image.

As one of the ink jet methods, there is a recording method using an ink for ink jet recording that can be cured by irradiation of radiation. According to this method, the productivity of printing can be improved and a sharp image can be formed by irradiating the ink immediately after ink ejection or after a certain time and curing the ink droplets.
By achieving high sensitivity of ink for ink jet recording that can be cured by irradiation with radiation such as ultraviolet rays, high curability is imparted to radiation, improving productivity of ink jet recording, reducing power consumption, and applying to radiation generators. There are many benefits such as longer life by reducing the load and prevention of volatilization of low molecular weight materials due to insufficient curing. In addition, high sensitivity improves the strength of the image formed by the ink for ink jet recording, particularly when applied to the formation of a lithographic printing plate. Will be obtained.

  In recent years, the curable inkjet method using such radiation, for example, ultraviolet rays has been attracting attention because it has a relatively low odor and can be recorded on a recording medium having no quick drying and no ink absorption.

  For the purpose of improving the adhesion to a recording medium, a cationic polymerization type ink composition having a small shrinkage rate upon UV curing has been proposed (for example, see Patent Document 1). However, these cationic polymerization type inks are not sufficiently stable at the time of storage due to a reaction based on an acid generated with the passage of time, which has been a major obstacle to practical use. For this reason, as an attempt to improve the storage stability, a technique of adding a basic compound or a thermal base generator has been proposed (for example, see Patent Documents 2 to 4), but the basic compound was generated by exposure. It has been found that a new problem arises that the curing sensitivity of the ink is lowered due to the inhibition of the acid function.

As described above, a curable composition that can be applied to a UV curable ink composition or the like and has high sensitivity to radiation irradiation and high strength film-forming properties has not yet been provided.
Japanese Patent Laid-Open No. 9-183928 JP 2003-312121 A JP 2003-341217 A JP 2004-91558 A

It is an object of the present invention to provide a curable composition that can be cured with high sensitivity to radiation and can form a high-strength film.
The present invention also provides an ink composition that can be cured with high sensitivity to radiation irradiation, can form a high-quality image, and has excellent adhesion to a recording medium, and the ink composition. It is an object of the present invention to provide an ink jet recording method used.

Means for solving the above problems are as follows.
<1> A polymerizable compound selected from the following compound group having two or more partial structures containing a cyclic ether having a 4-membered ring or more in the molecule, and a cationic polymerizable compound having a structure different from that of the polymerizable compound An ink composition comprising : a curable composition contained in a mass ratio of 10: 1 to 10: 100; and a colorant .

<2> A polymerizable compound selected from the compound group having two or more partial structures containing a cyclic ether having a 4-membered ring or more in the molecule, and a cationic polymerizable compound having a different structure from the polymerizable compound The ink composition according to <1>, in which the content ratio is 10: 3 to 10:80 on a mass basis.
<3> A polymerizable compound selected from the group of compounds having two or more partial structures containing a cyclic ether having a 4-membered ring or more in the molecule, and a cationic polymerizable compound having a different structure from the polymerizable compound The ink composition according to <1>, wherein the content ratio of is in the range of 10: 5 to 10:60 on a mass basis.
<4> The ink composition according to any one of <1> to <3>, further comprising a compound that generates an acid upon irradiation with radiation.
<5> ( a) A polymerizable compound selected from the group of compounds having two or more partial structures containing a cyclic ether having a 4-membered ring or more in the molecule, (a-2) What is the polymerizable compound? A different cationically polymerizable compound in a mass ratio of (a) :( a-2) in the range of 10: 3 to 10:80, and (b) a compound that generates an acid upon irradiation with radiation, and (C) a step of ejecting an ink composition containing a colorant onto a recording medium by an ink jet recording apparatus, and a step of irradiating the ejected ink composition with actinic radiation to cure the ink composition. Inkjet recording method.

The curable composition of the present invention is useful as an optical modeling material for resists, color filters, optical disks, and the like, in addition to ink compositions such as UV curable inks, paints, and adhesives.
In particular, the curable composition of the present invention can be suitably used as an inkjet ink composition, and such an ink composition can be cured with high sensitivity by radiation such as ultraviolet rays to form a high-quality image. Therefore, the ink composition has excellent adhesion to a recording medium. Furthermore, storage stability can be exhibited.
In addition, by applying an ink jet recording method, even when an ink composition is ejected onto a non-absorbable recording medium, it is cured with high sensitivity and a high-strength image area is directly formed based on digital data. sell. Therefore, the ink composition of the present invention is suitably used not only for the production of printed matter, but also for the production of a lithographic printing plate, particularly a lithographic printing plate having a large area of A2 or larger, and the lithographic printing plate obtained thereby Is excellent in printing durability.

ADVANTAGE OF THE INVENTION According to this invention, it can harden | cure with high sensitivity with respect to irradiation of a radiation, and can provide the curable composition in which high intensity | strength film formation is possible.
Further, according to the present invention, an ink composition that can be cured with high sensitivity to radiation irradiation, can form a high-quality image, and has excellent adhesion to a recording medium, and the ink composition An ink jet recording method using the object can be provided.

The ink composition of the present invention is a polymerizable compound selected from the group of compounds to be described later having at least two partial structures containing a cyclic ether portion having a 4-membered ring or more (hereinafter referred to as “specific polymerizable compound” as appropriate). And a colorant .

(Specific polymerizable compound)
The specific polymerizable compound according to the present invention will be described.
The specific polymerizable compound, at least two and a partial structure containing a 4-membered ring or more cyclic ether, has a partial structure represented by the following formula (I), into its molecular structure, from the group of compounds described below The polymerizable compound selected .
The specific polymerizable compound according to the present invention is preferably a compound that initiates a polymerization reaction and cures with an acid generated from a compound that generates an acid upon irradiation with radiation, which will be described later.

The cyclic ether having a 4-membered ring or more contained in the molecule is preferably a cyclic ether having 3 to 9 carbon atoms, and more preferably a cyclic ether having 3 to 7 carbon atoms.
Specifically, the cyclic ether contained in the partial structure (I) is particularly preferably a cyclic ether shown below from the viewpoint of reactivity.

Partial structure represented by the following general formula (I), the carbon atom in the cyclic ether, linked via a linking group such as an alkylene group, a polymerizable compound selected from the group of compounds described below Ru is formed.

In the general formula (I), R ¹ represents an alkylene group, a cycloalkylene group, or an arylene group.

In the general formula (I), examples of the alkylene group represented by R ¹ include alkylene groups having 2 to 12 carbon atoms (preferably 2 to 8, more preferably 2 to 6). Specific examples include an ethylene group, a propylene group, an isopropylene group, a butylene group, a pentylene group, and a hexylene group.
Examples of the cycloalkylene group represented by R ¹ include cycloalkylene groups having 4 to 12 (preferably 4 to 8, more preferably 5 to 7) carbon atoms. Specific examples include a cycloheptyl group, a cyclohexyl group, a cyclopentyl group, and a bicyclo ring group.

Examples of the arylene group represented by R ¹ include an arylene group having 6 to 12 carbon atoms (preferably 6 to 12, more preferably 6 to 8). Specifically, a phenyl group, a biphenyl group, a naphthyl group, and a benzyl group are preferable, and a phenyl group, a benzyl group, and the like can be given.
Among these, as R < ³ >, an alkyl group is preferable and it is more preferable that it is a C1-C4 alkyl group.

When R ¹ can be introduced, R ¹ may further have a substituent. Examples of the substituent that can be introduced into R ¹ include a halogen atom, an alkoxy group, an aryloxy group, a nitro group, and an amino group.

  The partial structure containing a cyclic ether moiety having 4 or more members in the specific polymerizable compound may have a substituent selected from an alkyl group, a cycloalkyl group, or an aryl group, and is connected to both cyclic ether moieties. The substituents to be formed may be the same or different from each other.

  Examples of the alkyl group that can be introduced into the cyclic ether moiety include an alkyl group having 1 to 10 carbon atoms (preferably 1 to 6, more preferably 1 to 4). Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, and a hexyl group.

  As the alkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and a pentyl group are preferable, and a methyl group, an ethyl group, a propyl group, and an isopropyl group are more preferable.

  Examples of the cycloalkyl group that can be introduced into the cyclic ether moiety include cycloalkyl groups having 4 to 12 carbon atoms (preferably 5 to 7, more preferably 5 to 6). Specific examples include a cycloheptyl group, a cyclohexyl group, a cyclopentyl group, and a bicyclo ring group.

  As said cycloalkyl group, a cycloheptyl group, a cyclohexyl group, and a cyclopentyl group are preferable, and a cycloheptyl group and a cyclohexyl group are more preferable.

Examples of the aryl group that can be introduced into the cyclic ether moiety include aryl groups having 6 to 12 (preferably 6 to 8) carbon atoms. Specific examples include a phenyl group, a biphenyl group, a naphthyl group, and a benzyl group.
As said aryl group, a phenyl group, a biphenyl group, a naphthyl group, and a benzyl group are preferable, and a phenyl group and a benzyl group are more preferable.

Among these, the cyclic ether moiety preferably has an alkyl group as a substituent, and more preferably an alkyl group having 1 to 4 carbon atoms.
The substituents of both cyclic ether moieties may be the same or different from each other, but are preferably the same from the viewpoint of synthesis suitability, and both are alkyl groups having 1 to 4 carbon atoms. Most preferable from the viewpoint of polymerization reactivity.
The specific polymerizable compound of the present invention particularly preferably has an embodiment in which both cyclic ether moieties have an alkyl group having ¹ to 4 carbon atoms and R ¹ is an alkylene group having 1 to 4 carbon atoms.

  n represents an integer of 1 to 8, is highly sensitive, and is preferably an integer of 2 to 8 from the viewpoint of maintaining the viscosity of the curable composition in a low viscosity range excellent in handling properties. An integer of 2 to 6 is more preferable, and an integer of 2 to 4 is particularly preferable.

When the substituent selected from the alkyl group, cycloalkyl group, or aryl group introduced into the cyclic ether moiety can be introduced, it may further have a substituent. Examples of the substituent that can be introduced include R ¹ The same as those mentioned in the above.

In the following, typical specific examples of the specific polymerizable compound according to the present invention having two partial structures containing a cyclic ether moiety will be given . The specific polymerizable compound according to the present invention is selected from the compound group consisting of these specific examples .

Specific examples of the specific polymerizable compound according to the present invention having three or four partial structures containing a cyclic ether moiety are given below . The specific polymerizable compound according to the present invention is selected from these specific examples .

  The specific polymerizable compound can be produced by a known method. This manufacturing method is described in detail in paragraph numbers [0030] to [0059] of the specification of Japanese Patent Application No. 2005-320963 previously proposed by the present inventor, and this manufacturing method can also be applied to the present invention.

  The content of the specific polymerizable compound is preferably 1 to 90% by mass, more preferably 1 to 70% by mass, and still more preferably 1 to 50% by mass with respect to the total solid content constituting the curable composition of the present invention. .

In the curable composition of the present invention, the polymerizable compound having a structure different from that of the other polymerizable compound described below in detail together with the specific polymerizable compound, that is, within the range not impairing the effects of the present invention . It combined the compound.
In the present invention, from the viewpoint of effectively suppressing shrinkage during curing of the composition, an epoxy compound or a specific polymerizable compound as described below as a specific polymerizable compound and another polymerizable compound. It is preferable to use a vinyl ether compound in combination with at least one compound selected from other oxetane compounds not included in the above.

(Other polymerizable compounds)
The cationically polymerizable compound that can be used in combination with the present invention is a compound that initiates a polymerization reaction by an acid generated from a compound that generates an acid upon irradiation with radiation and cures , and has a structure different from that of the polymerizable compound. There is no restriction | limiting in particular as a cationically polymerizable compound, The various well-known cationically polymerizable monomer known as a photocationic polymerizable monomer can be used. Examples of the cationic polymerizable monomer include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and 2001-2001. Examples thereof include epoxy compounds, vinyl ether compounds, and other oxetane compounds not included in the specific polymerizable compound described in each publication such as 220526.

Examples of the epoxy compound include aromatic epoxides, alicyclic epoxides, and aromatic epoxides.
Aromatic epoxides include di- or polyglycidyl ethers produced by the reaction of polyphenols having at least one aromatic nucleus or their alkylene oxide adducts and epichlorohydrin, such as bisphenol A or its alkylene oxides. Examples thereof include di- or polyglycidyl ethers of adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or its alkylene oxide adducts, and novolak-type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid. Or a cyclopentene oxide containing compound is mentioned preferably.
Examples of aliphatic epoxides include dihydric polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, and typical examples thereof include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, or 1,6. -Diglycidyl ether of alkylene glycol such as diglycidyl ether of hexanediol, polyglycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of glycerin or its alkylene oxide adduct, diglycidyl of polyethylene glycol or its adduct of alkylene oxide Diglycidyl of polyalkylene glycol typified by diglycidyl ether of ether, polypropylene glycol or its adduct of alkylene oxide Ether and the like. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

The monofunctional and polyfunctional epoxy compounds that can be used in the present invention are exemplified in detail.
Examples of monofunctional epoxy compounds include, for example, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene. Monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3-vinylcyclohexene oxide, etc. Is mentioned.

  Examples of polyfunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, and brominated bisphenol. S diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxy 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxy Hexylmethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ', 4'-epoxy- 6'-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylenebis (3,4-epoxycyclohexanecarboxylate) ), Dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl Ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8 -Diepoxyoctane, 1,2,5,6-diepoxycyclooctane and the like.

  Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable from the viewpoint of excellent curing speed, and alicyclic epoxides are particularly preferable.

  Examples of vinyl ether compounds include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, and trimethylol. Di- or trivinyl ether compounds such as propane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexanedimethanol monovinyl ether, n-pro Le vinyl ether, isopropyl vinyl, isopropenyl ether -o- propylene carbonate, dodecyl ether, diethylene glycol monovinyl ether, octadecyl vinyl ether.

Below, monofunctional vinyl ether and polyfunctional vinyl ether are illustrated in detail.
Examples of monofunctional vinyl ethers include, for example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, cyclohexyl methyl vinyl ether, 4 -Methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl D Ter, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloro Examples thereof include ethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxy polyethylene glycol vinyl ether and the like.

Examples of the polyfunctional vinyl ether include, for example, ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, and bisphenol F. Divinyl ethers such as alkylene oxide divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol Hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide addition Examples thereof include polyfunctional vinyl ethers such as pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.
As the vinyl ether compound, a di- or trivinyl ether compound is preferable from the viewpoints of curability, adhesion to a recording medium, surface hardness of the formed image, and the like, and a divinyl ether compound is particularly preferable.

Other oxetane compounds that can be used in combination with the present invention, specifically, cationically polymerizable compounds having a structure different from that of the polymerizable compound, are disclosed in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217. As described in the publication, known oxetane compounds can be arbitrarily selected and used. The compound having an oxetane ring that can be used in combination with the curable composition of the present invention is preferably a compound having 1 to 4 oxetane rings in the structure. By using such a compound, it becomes easy to maintain the viscosity of the composition in a favorable range of handling properties, and when applied to an ink composition or the like, the cured composition and the recording medium High adhesion can be obtained.

  Examples of the compound having 1 to 2 oxetane rings in the molecule used in the present invention include compounds represented by the following formulas (1) to (3).

R ^a1 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, a furyl group, or a thienyl group. When two R ^a1 are present in the molecule, they may be the same or different.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Preferred examples of the fluoroalkyl group include those in which any hydrogen of these alkyl groups is substituted with a fluorine atom.
R ^a2 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a group having an aromatic ring, an alkylcarbonyl group having 2 to 6 carbon atoms, or 2 to 6 carbon atoms. Represents an alkoxycarbonyl group, and an N-alkylcarbamoyl group having 2 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkenyl group include a 1-propenyl group, a 2-propenyl group, a 2-methyl-1-propenyl group, and 2-methyl-2. -Propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group and the like. Examples of the group having an aromatic ring include phenyl group, benzyl group, fluorobenzyl group, methoxybenzyl group, phenoxyethyl group and the like. Can be mentioned. As the alkylcarbonyl group, an ethylcarbonyl group, a propylcarbonyl group, a butylcarbonyl group, etc., as an alkoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, a butoxycarbonyl group, etc., as an N-alkylcarbamoyl group, Examples thereof include an ethylcarbamoyl group, a propylcarbamoyl group, a butylcarbamoyl group, and a pentylcarbamoyl group. R ^a2 may have a substituent, and examples of the substituent include an alkyl group of 1 to 6 and a fluorine atom.

R ^a3 is a linear or branched alkylene group, a linear or branched unsaturated hydrocarbon group, an alkylene group containing a carbonyl group or a carbonyl group, an alkylene group containing a carboxyl group, an alkylene group containing a carbamoyl group, or Represents a group shown below. Examples of the alkylene group include an ethylene group, a propylene group, and a butylene group. Examples of the poly (alkyleneoxy) group include a poly (ethyleneoxy) group and a poly (propyleneoxy) group. Examples of the unsaturated hydrocarbon group include a propenylene group, a methylpropenylene group, and a butenylene group.

When R ^a3 is the above polyvalent group, R ^a4 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a nitro group, a cyano group, a mercapto group, Represents a lower alkyl carboxyl group, a carboxyl group, or a carbamoyl group.
R ^a5 represents an oxygen atom, a sulfur atom, a methylene group, NH, SO, SO ₂ , C (CF ₃ ) ₂ , or C (CH ₃ ) ₂ .
R ^a6 represents an alkyl group having 1 to 4 carbon atoms or an aryl group, and n is an integer of 0 to 2,000. R ^a7 represents an alkyl group having 1 to 4 carbon atoms, an aryl group, or a monovalent group having the following structure. In the following formulae, R ^a8 is an alkyl group having 1 to 4 carbon atoms or an aryl group, and m is an integer of 0 to 100.

  As a compound represented by the formula (1), 3-ethyl-3-hydroxymethyloxetane (OXT-101: manufactured by Toagosei Co., Ltd.), 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (OXT) -212: manufactured by Toagosei Co., Ltd.) and 3-ethyl-3-phenoxymethyloxetane (OXT-211: manufactured by Toagosei Co., Ltd.). Examples of the compound represented by the formula (2) include 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene (OXT-121: Toagosei Co., Ltd.). ), Bis (3-ethyl-3-oxetanylmethyl) ether (OXT-221: Toagosei Co., Ltd.) is exemplified.

  Examples of the compound having 3 to 4 oxetane rings include a compound represented by the following formula (4).

In Formula (4), R ^a1 has the same ^meaning as in Formula (1). In addition, examples of R ^a9 that is a polyvalent linking group include branched alkylene groups having 1 to 12 carbon atoms such as groups represented by A to C below, and branched poly ( An alkyleneoxy) group or a branched polysiloxy group such as a group represented by E below. j is 3 or 4.

In the above A, R ^a10 represents a methyl group, an ethyl group, or a propyl group. Moreover, in said D, p is an integer of 1-10.

  Another embodiment of the oxetane compound that can be suitably used in the present invention includes a compound represented by the following formula (5) having an oxetane ring in the side chain.

In the formula (5), R ^a1 and R ^a8 have the same ^{meaning as} in the above formula. R ^a11 is an alkyl group having 1 to 4 carbon atoms or a trialkylsilyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group, and r is 1 to 4.

Such a compound having an oxetane ring is described in detail in JP-A No. 2003-341217, paragraph numbers 0021 to 0084, and the compounds described therein can be suitably used in the present invention.
Oxetane compounds described in JP-A-2004-91556 can also be used in the present invention. The compound is described in detail in paragraphs [0022] to [0058] of the publication.
Among the other oxetane compounds used in combination with the present invention, it is preferable to use a compound having one oxetane ring from the viewpoint of the viscosity and tackiness of the composition.

In the present invention, the specific polymerizable compound and another cationic polymerizable compound are used in combination, and the content ratio of the specific polymerizable compound and the other cationic polymerizable compound is 10: 1 to 10: 100 in terms of mass ratio. , and the 10: 3-10: 80 good preferred, 10: 5-10: 60 is more preferred.

((B) Compound that generates acid upon irradiation)
The curable composition of the present invention preferably contains a compound that generates an acid upon irradiation with radiation (hereinafter also referred to as a “photoacid generator”). In the present invention, the polymerization reaction of the polymerizable compound described above occurs due to the acid generated by the irradiation of radiation and is cured.
Examples of the photoacid generator that can be used in the ink composition of the present invention include a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, a photodecolorant for dyes, a photochromic agent, and a microresist. Light (400-200 nm ultraviolet light, far ultraviolet light, particularly preferably g-line, h-line, i-line, KrF excimer laser light), ArF excimer laser light, electron beam, X-ray, molecular beam or ion A compound that generates an acid upon irradiation with a beam or the like can be appropriately selected and used.

  Examples of such a photoacid generator include an onium salt compound such as diazonium salt, phosphonium salt, sulfonium salt, iodonium salt, imide sulfonate, oxime sulfonate, diazodisulfone, disulfone, which decomposes upon irradiation with radiation to generate an acid. Examples thereof include sulfonate compounds such as o-nitrobenzyl sulfonate.

  Other compounds (photoacid generators) that generate an acid upon irradiation with actinic rays or radiation used in the present invention include, for example, S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal etal, Polymer, 21, 423 (1980), U.S. Pat. Nos. 4,069,055, 4,069,056, Re 27,992, JP-A-3-140140, etc. An ammonium salt according to claim 1, C. Necker et al., Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055, 4,069,056, and the like; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent Nos. 104,143, 339,049, 410,201, JP-A-2-150848, JP-A-2-296514 and the like,

  J. et al. V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. MoI. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al. PolymerSci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al., Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al., Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al. PolymerSci. , Polymer Chem. Ed. 17, 2877 (1979), European Patent Nos. 370,693, 161,811, 410,201, 339,049, 233,567, 297,443, and 297,442. U.S. Pat.Nos. 3,902,114, 4,933,377, 4,760,013, 4,734,444, 2,833,827, German Patent 2, Nos. 904, 626, 3,604, 580, 3,604, 581, JP-A-7-28237, 8-27102 and the like,

  J. et al. V. Crivello et al., Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al. PolymerSci. , Polymer Chem. Ed. , 17, 1047 (1979), etc., selenonium salts, C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988) and other onium salts such as arsonium salts, US Pat. No. 3,905,815, Japanese Examined Patent Publication No. 46-4605, Japanese Unexamined Patent Publication No. 48-36281, Japanese Unexamined Patent Publication No. 55-55. -32070, JP-A-60-239736, JP-A-61-169835, JP-A-61-169837, JP-A-62-58241, JP-A-62-212401, JP-A-63-70243 , Organic halogen compounds described in JP-A-63-298339 and the like; Meier et al, J.A. Rad. Curing, 13 (4), 26 (1986), T.A. P. Gill et al, Inorg. Chem. , 19, 3007 (1980), D.M. Astruc, Acc. Chem. Res. , 19 (12), 377 (1986), and organometallic / organic halides described in JP-A-2-161445, etc.

  S. Hayase et al. Polymer Sci. 25, 753 (1987), E.I. Reichmanis et al. Polymer Sci. , Polymer Chem. Ed. , 23, 1 (1985), Q.M. Q. Zhu etal, J. et al. Photochem. 36, 85, 39, 317 (1987), B.R. Amit etal, Tetrahedron Lett. , (24) 2205 (1973), D.M. H. R. Barton et al. Chem. Soc. , 3571 (1965), p. M.M. Collins et al, J.A. Chem. Soc. Perkin I, 1695 (1975), M .; Rudinstein et al., Tetrahedron Lett. , (17), 1445 (1975), J. MoI. W. Walker et al. Am. Chem. Soc. 110, 7170 (1988), S.A. C. Busman et al. Imaging Technol. 11 (4), 191 (1985), H. et al. M.M. Houlihan et al, Macormolecules, 21, 2001 (1988), p. M.M. Collins et al. Chem. Soc. , Chem. Commun. 532 (1972), S.A. Hayase et al., Macromolecules, 18, 1799 (1985), E.I. Reichmanis et al. Electrochem. Soc. , Solid State Sci. Technol. , 130 (6), F.M. M.M. Houlihan et al, Macromolecules, 21, 2001 (1988), European Patent Nos. 0290,750, 046,083, 156,535, 271,851, 0,388,343, US Patent No. 3 , 901,710, 4,181,531, JP-A-60-198538, JP-A-53-133022 and the like, a photoacid generator having an o-nitrobenzyl type protecting group,

  M.M. TUNOOKA et al, Polymer Preprints Japan, 35 (8), G.M. Berner et al. Rad. Curing, 13 (4), W.M. J. et al. Mijs et al, Coating Technol. , 55 (697), 45 (1983), Akzo, H .; Adachi et al, Polymer Preprints, Japan, 37 (3), European Patent No. 0199,672, No. 84515, No. 044,115, No. 618,564, No. 0101,122, US Pat. No. 4,371 , 605, 4,431,774, JP-A 64-18143, JP-A-2-245756, JP-A-3-140109, etc. Compounds generating an acid, disulfone compounds described in JP-A-61-1166544 and JP-A-2-71270, diazo compounds described in JP-A-3-103854, JP-A-3-103856, and JP-A-4-210960 Examples thereof include ketosulfone and diazodisulfone compounds.

  Further, a group which generates an acid by these light, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, M.I. E. Woodhouse et al., J. MoI. Am. Chem. Soc. 104, 5586 (1982), S .; P. Pappas et al. Imaging Sci. , 30 (5), 218 (1986), S .; Kondo et al, Makromol. Chem. , Rapid Commun. , 9, 625 (1988), Y. et al. Yamada et al, Makromol. Chem. 152, 153, 163 (1972), J. Am. V. Crivello et al, J.A. PolymerSci. , Polymer Chem. Ed. 17, 3845 (1979), U.S. Pat. No. 3,849,137, German Patent No. 3,914,407, JP-A 63-26653, JP-A 55-164824, JP-A 62- 69263, JP-A 63-146038, JP-A 63-163452, JP-A 62-153853, JP-A 63-146029, and the like can be used. For example, diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, onium salts such as arsonium salts, organic halogen compounds, organic metal / organic halides, photoacid generators having o-nitrobenzyl type protecting groups Examples thereof include a compound capable of generating a sulfonic acid by photolysis represented by an agent, iminosulfonate, and the like, a disulfone compound, a diazoketosulfone, and a diazodisulfone compound.

  Furthermore, V. N. R. Pillai, Synthesis, (1), 1 (1980), A.M. Abad et al., Tetrahedron Lett. , (47) 4555 (1971), D.M. H. R. Barton et al, J.A. Chem. Soc. , (C), 329 (1970), U.S. Pat. No. 3,779,778, European Patent No. 126,712, and the like, compounds that generate an acid by light can also be used.

  Preferred examples of the photoacid generator that can be used in the present invention include compounds represented by the following formulas (b1), (b2), and (b3).

In formula (b1), R ²⁰¹ , R ²⁰² and R ²⁰³ each independently represents an organic group.
X ⁻ represents a non-nucleophilic anion, preferably a sulfonate anion, a carboxylate anion, a bis (alkylsulfonyl) amide anion, a tris (alkylsulfonyl) methide anion, BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ or the following The organic anion which has a carbon atom is preferable.

  Preferable organic anions include organic anions represented by the following formula.

Rc ¹ represents an organic group.
Examples of the organic group in Rc ¹ include those having 1 to 30 carbon atoms, and preferably an alkyl group, a cycloalkyl group, an aryl group, or a plurality of these are a single bond, —O—, —CO ₂ —, —S—. , —SO ₃ —, —SO ₂ N (Rd ¹ ) — and the like.

Rd ¹ represents a hydrogen atom or an alkyl group.
Rc ³ , Rc ⁴ and Rc ⁵ each independently represents an organic group.
Preferred examples of the organic group for Rc ³ , Rc ⁴ , and Rc ⁵ include the same organic groups as those for Rc ¹ , and most preferably a perfluoroalkyl group having 1 to 4 carbon atoms.
Rc ³ and Rc ⁴ may be bonded to form a ring.
Examples of the group formed by combining Rc ³ and Rc ⁴ include an alkylene group and an arylene group. Preferably, it is a C2-C4 perfluoroalkylene group.

As the organic groups of Rc ¹ and Rc ^{3 to} Rc ⁵ , the most preferable one is an alkyl group substituted at the 1-position with a fluorine atom or a fluoroalkyl group, or a phenyl group substituted with a fluorine atom or a fluoroalkyl group. By having a fluorine atom or a fluoroalkyl group, the acidity of the acid generated by light irradiation is increased and the sensitivity is improved.

The carbon number of the organic group as R ²⁰¹ , R ²⁰² and R ²⁰³ is generally 1 to 30, preferably 1 to 20.
Two of R ^{201 to} R ²⁰³ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. Examples of the group formed by combining two of R ^{201 to} R ²⁰³ include an alkylene group (eg, butylene group, pentylene group).

Specific examples of the organic group as R ²⁰¹ , R ²⁰² and R ²⁰³ include corresponding groups in the compounds (b1-1), (b1-2) and (b1-3) described later.

In addition, the compound which has two or more structures represented by Formula (b1) may be sufficient. For example, at least one of ^R 201 ^{to R 203} of a compound represented by the formula (b1) is at least one directly with ^R 201 ^{to R 203} of another compound represented by formula (b1), or a linking group It may be a compound having a structure bonded via

  Further preferred examples of the component (b1) include compounds (b1-1), (b1-2), and (b1-3) described below.

Compound (b1-1) is in which at least one aryl group ^R 201 ^{to R 203} in formula (b1), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.

In the arylsulfonium compound, all of R ^{201 to} R ²⁰³ may be an aryl group, or a part of R ^{201 to} R ²⁰³ may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group.

  Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, aryldicycloalkylsulfonium compounds, and the like.

  The aryl group of the arylsulfonium compound is preferably an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue, more preferably a phenyl group or an indole residue. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

As the alkyl group that the arylsulfonium compound has as necessary, a linear or branched alkyl group having 1 to 15 carbon atoms is preferable. For example, a methyl group, an ethyl group, a propyl group, an n-butyl group, sec -A butyl group, a t-butyl group, etc. can be mentioned.
The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

The aryl group, alkyl group and cycloalkyl group of R ^{201 to} R ²⁰³ are an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms). , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, and most preferred. Is an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms. The substituent may be substituted with any one of the three R ^{201 to} R ²⁰³ , or may be substituted with all three. When R ^{201 to} R ²⁰³ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (b1-2) will be described.
The compound (b1-2) is a compound when R ^{201 to} R ²⁰³ in the formula (b1) each independently represents an organic group that does not contain an aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group not containing an aromatic ring as R ^{201 to} R ²⁰³ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R ^{201 to} R ²⁰³ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, or an alkoxycarbonylmethyl group, particularly preferably Is a linear, branched 2-oxoalkyl group.

The alkyl group as R ^{201 to} R ²⁰³ may be either linear or branched, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group). Group, a butyl group, a pentyl group), and a linear, branched 2-oxoalkyl group, and an alkoxycarbonylmethyl group are more preferable.

The cycloalkyl group as R ^{201 to} R ²⁰³ preferably includes a cycloalkyl group having 3 to 10 carbon atoms (cyclopentyl group, cyclohexyl group, norbornyl group), and a cyclic 2-oxoalkyl group is more preferable.

Preferred examples of the linear, branched and cyclic 2-oxoalkyl group represented by R ^{201 to} R ²⁰³ include a group having> C═O at the 2-position of the above alkyl group or cycloalkyl group.
The alkoxy group in the alkoxycarbonylmethyl group as R ^{201 to} R ²⁰³ is preferably an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group).
R ²⁰¹ to R ²⁰³ is a halogen atom, an alkoxy group (for example, 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

  The compound (b1-3) is a compound represented by the following formula (b1-3) and is a compound having a phenacylsulfonium salt structure.

In formula (b1-3), R ^{1c to} R ^5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, or a halogen atom.
R ^6c and R ^7c each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
R ^x and R ^y each independently represents an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group.
Any two or more of R ^{1c to} R ^5c , R ^6c and R ^7c , and R ^x and R ^y may be bonded to each other to form a ring structure.
Zc ^- represents a non-nucleophilic anion, in X in Formula (b1) ^- may be the same as the non-nucleophilic anion.

The alkyl group as R ^{1c to} R ^7c may be either linear or branched, and for example, a linear and branched alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms (for example, Methyl group, ethyl group, linear or branched propyl group, linear or branched butyl group, linear or branched pentyl group).

Preferred examples of the cycloalkyl group represented by R ^{1c to} R ^7c include cycloalkyl groups having 3 to 8 carbon atoms (for example, a cyclopentyl group and a cyclohexyl group).

The alkoxy group as R ^{1c to} R ^{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Examples of the group formed by combining any two or more of R ^{1c to} R ^5c , R ^6c and R ^7c , and R ^x and R ^y include a butylene group and a pentylene group. This ring structure may contain an oxygen atom, a sulfur atom, an ester bond, or an amide bond.

Preferably, any one of R ^{1c to} R ^5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched, or cyclic alkoxy group, and more preferably the sum of the carbon number of R ^1c to R ^5c is 2-15. This is preferable because solvent solubility is further improved and generation of particles is suppressed during storage.

^Examples of the alkyl group and cycloalkyl group as R ^x and R ^y include the same alkyl groups and cycloalkyl groups as R ^{1c to} R ^7c .
R ^x and R ^y are preferably a 2-oxoalkyl group or an alkoxycarbonylmethyl group.
Examples of the 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R ^{1c to} R ^5c .
The alkoxy group in the alkoxycarbonylmethyl group may be the same as the alkoxy group as R ^1c to R ^5c.

R ^x and R ^y are preferably an alkyl group or cycloalkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more alkyl groups or cycloalkyl groups.

In formulas (b2) and (b3), R ^{204 to} R ²⁰⁷ each independently represents an aryl group, an alkyl group, or a cycloalkyl group. X ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as X ^{− in} formula (b1).

The aryl group for R ^{204 to} R ²⁰⁷ is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group.
The alkyl group as R ^{204 to} R ²⁰⁷ may be either linear or branched, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group). Group, butyl group, pentyl group). The cycloalkyl group as R ²⁰⁴ to R ²⁰⁷ is preferably, and a cycloalkyl group having 3 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, norbornyl).
The R ²⁰⁴ to R ²⁰⁷ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.

  Examples of the compound that generates an acid upon irradiation with actinic rays or radiation that may be used further include compounds represented by the following formulas (b4), (b5), and (b6).

In formulas (b4) to (b6), Ar ³ and Ar ⁴ each independently represent an aryl group.
R ²⁰⁶ , R ²⁰⁷ and R ²⁰⁸ each independently represents an alkyl group, a cycloalkyl group or an aryl group.
A represents an alkylene group, an alkenylene group or an arylene group.

Preferable examples of the photoacid generator include compounds represented by formulas (b1) to (b3).
Preferred compound examples ((b-1) to (b-96)) of (b) photoacid generator that can be used in the present invention are listed below, but the present invention is not limited thereto.

Further, oxazole derivatives and s-triazine derivatives described in JP-A No. 2002-122994, paragraph numbers [0029] to [0030] are also preferably used.
The onium salt compounds and sulfonate compounds exemplified in JP-A-2002-122994, paragraphs [0037] to [0063] can also be suitably used in the present invention.
Among these, those having a trichlorosulfonium salt structure such as the exemplified compounds (b-37) to (b-40) are particularly preferable from the viewpoint of sensitivity.

(B) A photo-acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the (b) photoacid generator in the ink composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably in terms of the total solid content of the ink composition. Is 1-7 mass%.

(Coloring agent)
The curable composition of the present invention may contain (c) a colorant. Moreover, when using the curable composition of this invention as an ink composition which can form a colored image, it is necessary to contain (c) a coloring agent.
The colorant that can be used in the present invention is not particularly limited, but pigments and oil-soluble dyes that are excellent in weather resistance and excellent in color reproducibility are preferable, and are selected from any known colorant such as a soluble dye. Can be used. The colorant that can be suitably used in the ink composition of the present invention or the ink composition for inkjet recording preferably does not function as a polymerization inhibitor in a polymerization reaction that is a curing reaction. This is because the sensitivity of the curing reaction by actinic radiation is not reduced.

<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.
Examples of these pigments include, for example, “Pigment Dictionary” (2000), edited by Seijiro Ito. Herbst, K.M. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Specific examples of organic pigments and inorganic pigments that can be used in the present invention include 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.).

  C. As a thing which exhibits red or 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. Pigment violet 19 (unsubstituted quinacridone), C.I. 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 blue or cyan, 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).

As a pigment exhibiting green, C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).
As a pigment exhibiting an orange color, C.I. I. An isoindoline pigment such as C.I. Pigment Orange 66 (isoindoline orange); I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

Examples of the black pigment include carbon black, titanium black, and aniline black.
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, and thus has a high hiding power and coloring power as a pigment. 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 as necessary.

For dispersing the pigment, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, or a wet jet mill is used. be able to.
It is also possible to add a dispersant when dispersing the pigment. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular weight copolymer, a modified polyacrylate, an aliphatic Examples thereof include polyvalent carboxylic acids, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate esters, and pigment derivatives. It is also preferable to use a commercially available polymer dispersant such as the Solsperse series from Zeneca.
Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

  In the ink composition, as a dispersion medium for various components such as pigments, a solvent may be added, or a cationic polymerizable compound which is a low molecular weight component without a solvent may be used as a dispersion medium. The ink composition to which the invention is applied is a radiation curable ink, and is preferably solvent-free in order to cure the ink after it is applied to a recording medium. This is because if the solvent remains in the cured ink image, the solvent resistance is deteriorated or a VOC (Volatile Organic Compound) problem of the remaining solvent occurs. From such a viewpoint, it is preferable to use a cationically polymerizable compound as the dispersion medium, and in particular, to select a cationically polymerizable monomer having the lowest viscosity from the viewpoint of improving dispersibility and handling properties of the ink composition.

The average particle diameter of the pigment is preferably 0.02 to 0.4 μm, more preferably 0.02 to 0.1 μm, and more preferably 0.02 to 0.07 μm.
The selection of pigment, dispersant, dispersion medium, dispersion conditions, and filtration conditions are set so that the average particle diameter of the pigment particles is within the above-mentioned preferable range. By controlling the particle size, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

<Dye>
The dye that can be used in the present invention is preferably oil-soluble. Specifically, it means that the solubility in water at 25 ° C. (the mass of the dye dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. Therefore, a so-called water-insoluble oil-soluble dye is preferably used.

The dye that can be used in the present invention preferably has an oil-solubilizing group introduced into the dye mother nucleus described above in order to dissolve the necessary amount in the ink composition.
As the oil-solubilizing group, long chain, branched alkyl group, long chain, branched alkoxy group, long chain, branched alkylthio group, long chain, branched alkylsulfonyl group, long chain, branched acyloxy group, long chain, branched alkoxycarbonyl group, Long chain, branched acyl group, long chain, branched acylamino group long chain, branched alkylsulfonylamino group, long chain, branched alkylaminosulfonyl group and these long chains, aryl groups containing branched substituents, aryloxy groups, aryloxycarbonyl Group, arylcarbonyloxy group, arylaminocarbonyl group, arylaminosulfonyl group, arylsulfonylamino group and the like.
In addition, for water-soluble dyes having carboxylic acid and sulfonic acid, long chain, branched alcohol, amine, phenol, aniline derivatives are used as oil-solubilizing alkoxycarbonyl groups, aryloxycarbonyl groups, alkylaminosulfonyl groups, A dye may be obtained by conversion to an arylaminosulfonyl group.

The oil-soluble dye preferably has a melting point of 200 ° C. or lower, more preferably has a melting point of 150 ° C. or lower, and still more preferably has a melting point of 100 ° C. or lower. By using an oil-soluble dye having a low melting point, the precipitation of dye crystals in the ink composition is suppressed, and the storage stability of the ink composition is improved.
Further, it is desirable that the oxidation potential is noble (high) in order to improve fading, particularly resistance to oxidizing substances such as ozone and curing characteristics. For this reason, as the oil-soluble dye used in the present invention, those having an oxidation potential of 1.0 V (vs SCE) or more are preferably used. The oxidation potential is preferably higher, the oxidation potential is more preferably 1.1 V (vs SCE) or more, and particularly preferably 1.15 V (vs SCE) or more.

As the yellow dye, a compound having a structure represented by the general formula (Y-I) described in JP-A No. 2004-250483 is preferable.
Particularly preferred dyes are dyes represented by the general formulas (Y-II) to (Y-IV) described in paragraph [0034] of JP-A No. 2004-250483. And the compounds described in paragraph numbers [0060] to [0071] of JP-A-250483. The oil-soluble dye of the general formula (Y-I) described in the publication may be used not only for yellow but also for inks of any color such as black ink and red ink.

The magenta dye is preferably a compound having a structure represented by the general formulas (3) and (4) described in JP-A No. 2002-114930. Specific examples include paragraphs of JP-A No. 2002-114930. Examples include the compounds described in [0054] to [0073].
Particularly preferred dyes are azo dyes represented by the general formulas (M-1) to (M-2) described in paragraph numbers [0084] to [0122] of JP-A No. 2002-121414, and specific examples Examples thereof include compounds described in paragraph numbers [0123] to [0132] of JP-A No. 2002-121414. The oil-soluble dyes represented by the general formulas (3), (4) and (M-1) to (M-2) described in the publication are used not only for magenta but also for any color ink such as black ink and red ink. May be.

Examples of the cyan dye include dyes represented by formulas (I) to (IV) described in JP-A No. 2001-181547, and paragraphs [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) described above are preferred, and specific examples include paragraph numbers [0052] to [0066] of JP-A No. 2001-181547. Examples thereof include the compounds described in paragraph Nos. [0079] to [0081] of Kai 2002-121414.
Particularly preferred dyes are phthalocyanine dyes represented by general formulas (CI) and (C-II) described in paragraphs [0133] to [0196] of JP-A No. 2002-121414, A phthalocyanine dye represented by formula (C-II) is preferred. Specific examples thereof include the compounds described in JP-A No. 2002-121414, paragraph numbers [0198] to [0201]. The oil-soluble dyes of the formulas (I) to (IV), (IV-1) to (IV-4), (CI) and (C-II) are not only cyan but also black ink or green ink. The ink may be used for any color ink.

  These colorants are preferably added in an amount of 1 to 20% by mass in terms of solid content in the composition, and more preferably 2 to 10% by mass.

(Other ingredients)
The various additives that can be used in the present invention as necessary are described below.
[Ultraviolet absorber]
In the present invention, an ultraviolet absorber can be used from the viewpoint of improving the weather resistance of the obtained image and preventing discoloration.
Examples of the ultraviolet absorber are described in JP-A-58-185679, JP-A-61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194433, US Pat. No. 3,214,463, etc. Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP The triazine compounds described in JP-A-8-501291, Research Disclosure No. Examples thereof include compounds described in No. 24239, compounds that emit ultraviolet light by absorbing ultraviolet rays typified by stilbene and benzoxazole compounds, so-called fluorescent brighteners, and the like.
The addition amount is appropriately selected according to the purpose, but generally it is preferably 0.5 to 15% by mass in terms of solid content.

[Sensitizer]
In the present invention, a sensitizer may be added, if necessary, for the purpose of improving the acid generation efficiency of the photoacid generator and increasing the photosensitive wavelength. Any sensitizer may be used as long as the photoacid generator is sensitized by an electron transfer mechanism or an energy transfer mechanism. Preferably, aromatic polycondensed compounds such as anthracene, 9,10-dialkoxyanthracene, pyrene and perylene, aromatic ketone compounds such as acetophenone, benzophenone, thioxanthone and Michlerketone, heterocyclic compounds such as phenothiazine and N-aryloxazolidinone Is mentioned. Although the addition amount is appropriately selected according to the purpose, it is preferably used in an amount of 0.01 to 1 mol%, more preferably 0.1 to 0.5 mol% with respect to (b) the photoacid generator.

〔Antioxidant〕
An antioxidant can be added to improve the stability of the composition. Examples of the antioxidant include European published patents, 223739, 309401, 309402, 310551, 310552, 359416, and 3435443. JP, 54-85535, 62-262417, 63-113536, 63-163351, JP-A-2-262654, JP-A-2-71262, Examples thereof include those described in Kaihei 3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275, and the like.
Although the addition amount is appropriately selected according to the purpose, it is preferably 0.1 to 8% by mass in terms of solid content.

[Anti-fading agent]
In the present invention, various organic and metal complex anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. Examples of the metal complex anti-fading agent include nickel complexes and zinc complexes. No. 17643, No. VII, I to J, ibid. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .
Although the addition amount is appropriately selected according to the purpose, it is preferably 0.1 to 8% by mass in terms of solid content.

[Conductive salts]
In the present invention, conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, and dimethylamine hydrochloride can be added for the purpose of controlling ejection properties.

〔solvent〕
In the present invention, it is also effective to add a very small amount of an organic solvent in order to improve the adhesion to the recording medium.
Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, and tert-butanol, and chlorine such as chloroform and methylene chloride. Solvents, aromatic solvents such as benzene and toluene, ester solvents such as ethyl acetate, butyl acetate and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, glycols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether And ether solvents.
In this case, it is effective to add the solvent within a range that does not cause the problem of solvent resistance and VOC, and the amount is preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the whole ink composition. % Range.

[Polymer compound]
Various polymer compounds can be added to the present invention in order to adjust film properties. High molecular compounds include acrylic polymers, polyvinyl butyral resins, polyurethane resins, polyamide resins, polyester resins, epoxy resins, phenol resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl formal resins, shellacs, vinyl resins, acrylic resins. Rubber resins, waxes and other natural resins can be used. Two or more of these may be used in combination. Of these, vinyl copolymer obtained by copolymerization of acrylic monomers is preferred. Furthermore, a copolymer containing “carboxyl group-containing monomer”, “methacrylic acid alkyl ester”, or “acrylic acid alkyl ester” as a structural unit is also preferably used as the copolymer composition of the polymer binder.

[Surfactant]
A surfactant may be added to the present invention.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. An organic fluoro compound may be used in place of the surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compounds include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). No. (columns 8 to 17) and those described in JP-A Nos. 62-135826.

In addition to this, if necessary, for example, leveling additives, matting agents, waxes for adjusting film physical properties, polymerization to inhibit the adhesion to recording media such as polyolefin and PET, and the like, The tackifier which does not do can be contained.
As the tackifier, specifically, a high molecular weight adhesive polymer described in JP-A-2001-49200, 5-6p (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms). An ester with an alcohol having, an ester of (meth) acrylic acid with an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer comprising an ester of (meth) acrylic acid with an aromatic alcohol having 6 to 14 carbon atoms And a low molecular weight tackifying resin having a polymerizable unsaturated bond.

-Preferred embodiment of ink composition-
As described above, the ink composition to which the curable composition of the present invention is applied (the ink composition of the present invention) includes, as described above, a specific polymerizable compound, a compound that generates an acid upon irradiation with radiation, and other optionally contained compounds. It contains a polymerizable compound, a colorant, and the like. These components are preferably 1 to 10% by mass, more preferably 2 to 8% by mass, and all polymerizable compounds including a specific polymerizable compound, preferably 1 to 10% by mass with respect to the total mass of the ink composition. 1 to 97% by mass, more preferably 30 to 95% by mass. The compound that generates an acid upon irradiation with radiation is preferably 0.01 to 20% by mass, more preferably 0.1 to 20% by mass, based on the total polymerizable compound including the specific polymerizable compound. It is suitable to contain.

  When the ink composition of the present invention is used as an ink for inkjet recording, the viscosity is preferably at a temperature at the time of ejection (for example, 40 to 80 ° C., preferably 25 to 30 ° C.) in consideration of ejection properties. It is 7-30 mPa * s, More preferably, it is 7-20 mPa * s. For example, the viscosity of the ink composition of the present invention at room temperature (25 to 30 ° C.) is preferably 35 to 500 mPa · s, more preferably 35 to 200 mPa · s. It is preferable that the composition ratio of the ink composition of the present invention is appropriately adjusted so that the viscosity is in the above range. By setting the viscosity at room temperature high, even when a porous recording medium is used, ink penetration into the recording medium can be avoided, and uncured monomers and odors can be reduced. Further, it is preferable because ink bleeding at the time of ink droplet landing can be suppressed, and as a result, the image quality is improved.

  The surface tension of the ink composition of the present invention is preferably 20 to 30 mN / m, more preferably 23 to 28 mN / m. When recording on various recording media such as polyolefin, PET, coated paper, and non-coated paper, 20 mN / m or more is preferable from the viewpoint of bleeding and penetration, and the wettability is preferably 30 mN / m or less.

  The ink composition of the present invention is suitably used as an inkjet recording ink. When used as an ink for ink jet recording, the ink composition is ejected onto a recording medium by an ink jet printer, and then the ejected ink composition is irradiated with radiation and cured to perform recording.

  In the printed matter obtained with this ink, the image portion is cured by irradiation with radiation such as ultraviolet rays, and the strength of the image portion is excellent. Therefore, in addition to image formation with ink, for example, an ink receiving layer (image image of a lithographic printing plate) Part), and can be used for various purposes.

[Inkjet recording method]
The ink jet recording method to which the ink composition of the present invention is suitably applied (the ink jet recording method of the present invention) will be described below.
The ink jet recording method of the present invention comprises a step of ejecting the ink composition of the present invention onto a recording medium (support, recording material, etc.) by an ink jet recording apparatus, and the ejected ink composition. And a step of irradiating the material with actinic radiation to cure the ink composition. The cured ink composition forms an image on the recording medium.

The recording medium to be applied to the ink jet recording method of the present invention is not particularly limited, and various non-absorbing resin materials used for ordinary non-coated paper, coated paper, and so-called soft packaging, or the like. A resin film formed into a film can be used, and examples of the various plastic films include PET film, OPS film, OPP film, ONy film, PVC film, PE film, and TAC film. In addition, examples of the plastic that can be used as a recording medium material include polycarbonate, acrylic resin, ABS, polyacetal, PVA, and rubbers. Metals and glasses can also be used as the recording medium.
In addition, the ink composition of the present invention has little heat shrinkage at the time of curing and excellent adhesion to the substrate (recording medium). Films that are easily deformed, such as heat-shrinkable PET film, OPS film, OPP film, ONy film, PVC film, etc., have the advantage that a high-definition image can be formed.
Furthermore, examples of the recording material applicable to the present invention include a support for a lithographic printing plate described later.

Examples of the actinic radiation applied to the ink jet recording method of the present invention include α rays, γ rays, X rays, ultraviolet rays, visible rays, infrared rays, and electron beams. The peak wavelength of the actinic radiation is preferably 200 to 600 nm, more preferably 300 to 450 nm, and still more preferably 350 to 420 nm. The output of active radiation is preferably 2,000 mJ / cm ² or less, more preferably from 10 to 2,000 mJ / cm ^2, more preferably, be 20 to 1,000 mJ / cm ² Particularly preferably, it is 50 to 800 mJ / cm ² .
In particular, in the ink jet recording method of the present invention, radiation irradiation generates ultraviolet rays having an emission wavelength peak of 350 to 420 nm and a maximum illuminance on the surface of the recording medium of 10 to 1,000 mW / cm ^2. Irradiation from a light emitting diode is preferred.

  In addition to the above, regarding various conditions applied to the ink jet recording method of the present invention and details of the ink jet recording apparatus, etc., a lithographic printing plate and a method for producing a lithographic printing plate, which are preferred applications of the ink jet recording method of the present invention Will be described later.

  According to the ink jet recording method of the present invention, the dot diameter of the landed ink can be kept constant even on various supports (recording media) having different surface wettability, and the image quality can be improved. it can. In order to obtain a color image according to the present invention, it is preferable to superimpose in order from the color with the lowest brightness. By superimposing the inks in the order of low lightness, the irradiation line can easily reach the lower ink, and good curing sensitivity, reduction of residual monomers, reduction of odor, and improvement of adhesion can be expected. In addition, irradiation can be performed by discharging all colors and collectively exposing, but exposure for each color is preferable from the viewpoint of promoting curing.

[Lithographic printing plate and lithographic printing plate manufacturing method]
By using the lithographic printing plate support as a recording medium by the inkjet recording method of the present invention, a lithographic printing plate can be produced. In this case, first, the step of discharging the ink composition of the present invention onto a support is carried out, and then the ink composition is irradiated with actinic radiation to cure the ink composition. A hydrophobic image formed by curing the ink composition is formed on a support, and a lithographic printing plate can be produced.
The lithographic printing plate thus obtained is produced by the ink jet recording method of the present invention and has a support and a hydrophobic image formed on the support.

  Conventionally, so-called PS plates having a configuration in which a lipophilic photosensitive resin layer is provided on a hydrophilic support have been widely used as lithographic printing plates. As a method for producing the PS plate, a desired printing plate is usually obtained by performing mask exposure (surface exposure) through a lith film and then dissolving and removing the non-exposed portion. However, in recent years, digitization techniques for electronically processing, storing, and outputting image information using a computer have become widespread, and a new image output method corresponding to the technique has been demanded. In particular, computer-to-plate (CTP) technology has been developed that scans highly-preferred light such as laser light according to digitized image information without using a lithographic film, and directly produces a printing plate. Yes.

  Examples of a method for obtaining a lithographic printing plate that enables such scanning exposure include a method of directly producing a lithographic printing plate using an ink composition or an ink composition for ink jet recording. This is because an ink is ejected onto a support (preferably a hydrophilic support) by an ink jet method or the like, and exposed to actinic radiation, thereby exposing an ink composition or an ink jet recording ink portion. A printing plate having a desired image (preferably a hydrophobic image) is obtained. The ink composition or ink for ink jet recording suitable for such a system is the ink composition or ink for ink jet recording of the present invention.

[Step of discharging ink composition onto support]
(Support)
The support (recording medium) in the planographic printing plate of the present invention is not particularly limited as long as it is a dimensionally stable plate-like support. The support is preferably a hydrophilic support. Examples of the support include paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), and plastic film (eg, cellulose diacetate, triacetic acid). Cellulose, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. . A preferable support includes a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a known material can be used as appropriate.

The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm.
Prior to using the aluminum plate, it is preferable to perform surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion between the image recording layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (roughening treatment for dissolving the electrochemical surface), chemical surface treatment, etc. Roughening treatment (roughening treatment that selectively dissolves the surface chemically) can be mentioned.
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Also, a transfer method in which the uneven shape is transferred with a roll provided with unevenness in the aluminum rolling step may be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.
The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used and cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / ^{m 2,} and more preferably 1.5 to 4.0 g / ^{m 2.} Within this range, good printing durability and good scratch resistance of the non-image area of the planographic printing plate can be obtained, which is preferable.

  As the support used in the lithographic printing plate of the present invention, the surface treatment as described above may be used as it is, and the substrate having the anodized film may be used as it is. In order to further improve the heat insulation and the like, if necessary, the micropore enlargement treatment and sealing treatment of the anodized film described in JP-A-2001-253181 and JP-A-2001-322365, and hydrophilic The surface hydrophilization treatment soaked in an aqueous solution containing a functional compound can be appropriately selected and performed. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

<Sealing treatment>
Sealing treatment includes vapor sealing, single treatment with zirconic fluoride, treatment with an aqueous solution containing an inorganic fluorine compound such as treatment with sodium fluoride, vapor sealing with addition of lithium chloride, sealing with hot water. Hole processing is also possible.
Among these, a sealing treatment with an aqueous solution containing an inorganic fluorine compound, a sealing treatment with water vapor, and a sealing treatment with hot water are preferable. Each will be described below.

-Sealing treatment with aqueous solution containing inorganic fluorine compound-
As the inorganic fluorine compound used for the sealing treatment with an aqueous solution containing an inorganic fluorine compound, a metal fluoride is preferably exemplified.
Specifically, for example, sodium fluoride, potassium fluoride, calcium fluoride, magnesium fluoride, sodium fluoride zirconate, potassium fluoride zirconate, sodium fluoride titanate, potassium fluoride titanate, zircon fluoride Ammonium acid, ammonium fluoride titanate, potassium fluoride titanate, fluorinated zirconate, fluorinated titanate, hexafluorosilicic acid, nickel fluoride, iron fluoride, phosphor fluoride, ammonium fluoride phosphate It is done. Of these, sodium fluorinated zirconate, sodium fluorinated titanate, fluorinated zirconic acid, and fluorinated titanic acid are preferable.

The concentration of the inorganic fluorine compound in the aqueous solution is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more in terms of sufficiently sealing the micropores of the anodized film. Further, in terms of stain resistance, the content is preferably 1% by mass or less, and more preferably 0.5% by mass or less.
It is preferable that the aqueous solution containing the inorganic fluorine compound further contains a phosphate compound. The inclusion of a phosphate compound is preferable because the hydrophilicity of the surface of the anodized film is improved, and the on-press developability and stain resistance can be improved.

Suitable examples of the phosphate compound include phosphates of metals such as alkali metals and alkaline earth metals.
Specifically, for example, zinc phosphate, aluminum phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, monoammonium phosphate, monopotassium phosphate, monosodium phosphate, dihydrogen phosphate Potassium, dipotassium hydrogen phosphate, calcium phosphate, sodium ammonium hydrogen phosphate, magnesium hydrogen phosphate, magnesium phosphate, ferrous phosphate, ferric phosphate, sodium dihydrogen phosphate, sodium phosphate, hydrogen phosphate Disodium, lead phosphate, diammonium phosphate, calcium dihydrogen phosphate, lithium phosphate, phosphotungstic acid, ammonium phosphotungstate, sodium phosphotungstate, ammonium phosphomolybdate, sodium phosphomolybdate, sodium phosphite , Tripolyphosphate Potassium, and sodium pyrophosphate. Of these, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate are preferable.
The combination of the inorganic fluorine compound and the phosphate compound is not particularly limited, but the aqueous solution contains at least sodium zirconate fluoride as the inorganic fluorine compound and contains at least sodium dihydrogen phosphate as the phosphate compound. It is preferable.
The concentration of the phosphate compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of improving on-press developability and stain resistance. Moreover, it is preferable that it is 20 mass% or less at a soluble point, and it is more preferable that it is 5 mass% or less.

The ratio of each compound in the aqueous solution is not particularly limited, but the mass ratio of the inorganic fluorine compound and the phosphate compound is preferably 1/200 to 10/1, and preferably 1/30 to 2/1. Is more preferable.
The temperature of the aqueous solution is preferably 20 ° C. or higher, more preferably 40 ° C. or higher, 100 ° C. or lower, and more preferably 80 ° C. or lower.
The aqueous solution preferably has a pH of 1 or more, more preferably has a pH of 2 or more, preferably has a pH of 11 or less, and more preferably has a pH of 5 or less.
The method for sealing with an aqueous solution containing an inorganic fluorine compound is not particularly limited, and examples thereof include an immersion method and a spray method. These may be used alone or in combination, or may be used in combination of two or more.
Of these, the dipping method is preferred. When processing using the dipping method, the processing time is preferably 1 second or longer, more preferably 3 seconds or longer, 100 seconds or shorter, and 20 seconds or shorter. More preferred.

-Sealing treatment with water vapor-
Examples of the sealing treatment with water vapor include a method of bringing pressurized or normal pressure water vapor into contact with the anodized film continuously or discontinuously.
The temperature of the water vapor is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 105 ° C. or lower.
The water vapor pressure is preferably in the range (1.008 × 10 ^{5 to} 1.043 × 10 ⁵ Pa) from (atmospheric pressure−50 mmAq) to (atmospheric pressure + 300 mmAq).
The time for which the water vapor is contacted is preferably 1 second or longer, more preferably 3 seconds or longer, 100 seconds or shorter, and more preferably 20 seconds or shorter.

-Sealing treatment with hot water-
Examples of the sealing treatment with water vapor include a method of immersing an aluminum plate on which an anodized film is formed in hot water.
The hot water may contain an inorganic salt (for example, phosphate) or an organic salt.
The temperature of the hot water is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 100 ° C. or lower.
The time for immersion in hot water is preferably 1 second or longer, more preferably 3 seconds or longer, 100 seconds or shorter, more preferably 20 seconds or shorter.
Examples of the hydrophilization treatment used in the present invention include US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There is an alkali metal silicate method as described in the book. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in each specification of No.272.
The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the image recording layer, good printing durability and good stain resistance are obtained, which is preferable.

  When the ink composition or ink composition for ink jet recording of the present invention is discharged onto the surface of a hydrophilic support, the ink composition or ink composition for ink jet recording is preferably 40 to 80 ° C., more preferably 25 to 25 ° C. It is preferable to discharge after heating to 30 ° C. and lowering the viscosity of the ink composition to preferably 7 to 30 mPa · s, more preferably 7 to 20 mPa · s. In particular, it is preferable to use an ink composition having an ink viscosity of 35 to 500 mP · s at 25 ° C. because a great effect can be obtained. By using this method, high ejection stability can be realized.

  A radiation curable ink composition such as the ink composition of the present invention generally has a higher viscosity than a water-based ink that is usually used in an ink composition or an ink for inkjet recording, and therefore has a large viscosity fluctuation due to temperature fluctuations during ejection. . The ink viscosity fluctuation has a great influence on the change of the droplet size and the change of the droplet discharge speed, and further causes the deterioration of the image quality. Therefore, it is necessary to keep the temperature of the ink at the time of ejection as constant as possible. Therefore, in the present invention, it is appropriate that the temperature control range is set to ± 5 ° C. of the set temperature, preferably ± 2 ° C. of the set temperature, more preferably set temperature ± 1 ° C.

(Inkjet recording device)
There is no restriction | limiting in particular as an inkjet recording device used for this invention, A commercially available inkjet recording device can be used. That is, in the present invention, recording can be performed on a recording medium using a commercially available inkjet recording apparatus.
Examples of the ink jet recording apparatus that can be used in the present invention include an ink supply system, a temperature sensor, and an actinic radiation source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head has a multi-size dot of 1 to 100 pl, preferably 8 to 30 pl, for example, 320 × 320 to 4000 × 4000 dpi, preferably 400 × 400 to 1600 × 1600 dpi, and more preferably 720 × 720 dpi. It can drive so that it can discharge with the resolution of. In the present invention, dpi represents the number of dots per 2.54 cm.

  As described above, since it is desirable for the radiation curable ink to have a constant temperature for the ink to be ejected, heat insulation and heating can be performed from the ink supply tank to the inkjet head portion. The temperature control method is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors at each piping site and perform heating control according to the ink flow rate and the environmental temperature. The temperature sensor can be provided in the vicinity of the ink supply tank and the nozzle of the inkjet head. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of thermal energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

[Step of forming a hydrophobic image on the support by curing the ink composition by irradiating the discharged ink composition with actinic radiation and curing the ink composition]
The ink composition ejected on the surface of the support is cured by irradiation with actinic radiation. At this time, when a sensitizing dye is present together with a polymerization initiator (photoinitiator) in the ink composition, the sensitizing dye in the system absorbs actinic radiation to be in an excited state and comes into contact with the polymerization initiator. By promoting the decomposition of the polymerization initiator, a more sensitive curing reaction can be achieved.

Here, α rays, γ rays, electron beams, X rays, ultraviolet rays, visible light, infrared rays, or the like can be used as the active radiation used. The peak wavelength of the actinic radiation is, for example, 200 to 600 nm, preferably 300 to 450 nm, and more preferably 350 to 420 nm, although it depends on the absorption characteristics of the sensitizing dye. In the present invention, the polymerization initiating system has sufficient sensitivity even with low-power actinic radiation. Thus, the output of the actinic radiation is, for example, 2,000 mJ / cm ² or less, preferably, 10 to 2,000 mJ / cm ^2, more preferably, 20 to 1,000 mJ / cm ^2, more preferably, 50 to 800 mJ An irradiation energy of / cm ² is appropriate. The active radiation, the illumination intensity on the exposed surface is, for example, 10 to 2,000 mW / cm ^2, preferably, it is suitable to be irradiated at 20 to 1,000 mW / cm ^2.

  As the active radiation source, a mercury lamp, a gas / solid laser or the like is mainly used, and a mercury lamp and a metal halide lamp are widely known as the ultraviolet light curable ink jet. However, from the viewpoint of environmental protection, mercury-free is strongly desired, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long life, have high efficiency, and are low in cost, and are expected as light sources for photocurable ink jets.

In the present invention, a light emitting diode (LED) and a laser diode (LD) can be used as the active radiation source. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. When even shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit actinic radiation centered between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. The actinic radiation source particularly preferred in the present invention is a UV-LED, particularly preferably a UV-LED having a peak wavelength at 350 to 420 nm.
Preferably maximum illumination intensity of the LED on a recording medium is 10 to 2,000 mW / cm ^2, more preferably 20 to 1,000 mW / cm ^2, particularly preferably at 50 to 800 mW / cm ² is there.

In the present invention, it is appropriate that the ink composition is irradiated with such actinic radiation for, for example, 0.01 to 120 seconds, preferably 0.1 to 90 seconds.
The contents disclosed in JP-A-60-132767 can be applied as the irradiation conditions and the basic irradiation method of actinic radiation. Specifically, the light source is provided on both sides of the head unit including the ink ejection device, and the head unit and the light source are scanned by a so-called shuttle method. Irradiation with actinic radiation takes a certain time (for example, 0.01 to 0.5 seconds, preferably 0.01 to 0.3 seconds, more preferably 0.01 to 0.15 seconds) after ink landing. Will be done. In this way, by controlling the time from ink landing to irradiation to an extremely short time, it is possible to prevent the ink that has landed on the recording medium from spreading before curing. Further, since the ink can be exposed to a porous recording medium before the ink penetrates to a deep part where the light source does not reach, residual unreacted monomer can be suppressed, and as a result, odor can be reduced. .
Further, the curing may be completed by another light source that is not driven. WO99 / 54415 pamphlet discloses a method using an optical fiber and a method of irradiating a recording unit with UV light by applying a collimated light source to a mirror surface provided on the side surface of the head unit.

  Thus, according to the method for producing a lithographic printing plate of the present invention, the ink composition of the present invention can be used to cure by irradiation with actinic radiation to form a hydrophobic image on the surface of the support. .

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples.

[Example 1]
(Preparation of cationically polymerizable ink)
<Preparation of ink>
<Yellow ink 1>
・ C. I. Pigment Yellow 13 5 parts by mass / photocation polymerization initiator: triphenylsulfonium salt
(UVI-6992, manufactured by Dow Chemical Company) 6 parts by mass / sensitizing dye: 9,10-dibutoxyanthracene 3 parts by mass / polymerizable compound Monomer: 3,4-epoxycyclohexylmethyl-
3 ′, 4′-epoxycyclohexanecarboxylate (Celoxide 2021A: manufactured by Daicel UCB) 35 parts by mass Monomer: 3-ethyl-3-hydroxymethyloxetane (OXT-101: manufactured by Toagosei Co., Ltd.) 24 parts by mass Monomer : Specific polymerizable compound (a-1) (the following structure) 27 parts by mass

<Magenta ink 1>
・ C. I. Pigment Red 57: 1 5 parts by mass / photocation polymerization initiator: triphenylsulfonium salt
(UVI-6992, manufactured by Dow Chemical Company) 6 parts by mass / sensitizing dye: 9,10-dibutoxyanthracene 3 parts by mass / polymerizable compound Monomer: 3,4-epoxycyclohexylmethyl-
3 ′, 4′-epoxycyclohexanecarboxylate (Celoxide 2021A: manufactured by Daicel UCB) 35 parts by mass Monomer: 3-ethyl-3-hydroxymethyloxetane (OXT-101: manufactured by Toagosei Co., Ltd.) 24 parts by mass Monomer : Specific polymerizable compound (a-1) (the above structure) 27 parts by mass

<Cyan ink 1>
・ C. I. Pigment Blue 15: 3 5 parts by mass / photocation polymerization initiator: triphenylsulfonium salt
(UVI-6992, manufactured by Dow Chemical Company) 6 parts by mass / sensitizing dye: 9,10-dibutoxyanthracene 3 parts by mass / polymerizable compound Monomer: 3,4-epoxycyclohexylmethyl-
3 ′, 4′-epoxycyclohexanecarboxylate (Celoxide 2021A: manufactured by Daicel UCB) 35 parts by mass Monomer: 3-ethyl-3-hydroxymethyloxetane (OXT-101: manufactured by Toagosei Co., Ltd.) 24 parts by mass Monomer : Specific polymerizable compound (a-1) (the above structure) 27 parts by mass

<Black ink 1>
・ C. I. Pigment Black 7 5 parts by mass / photocation polymerization initiator: triphenylsulfonium salt
(UVI-6992, manufactured by Dow Chemical Company) 6 parts by mass / sensitizing dye: 9,10-dibutoxyanthracene 3 parts by mass / polymerizable compound Monomer: 3,4-epoxycyclohexylmethyl-
3 ′, 4′-epoxycyclohexanecarboxylate (Celoxide 2021A: manufactured by Daicel UCB) 35 parts by mass Monomer: 3-ethyl-3-hydroxymethyloxetane (OXT-101: manufactured by Toagosei Co., Ltd.) 24 parts by mass Monomer : Specific polymerizable compound (a-1) (the above structure) 27 parts by mass

  The crude color inks 1 prepared as described above were filtered with a filter having an absolute filtration accuracy of 2 μm to obtain inks 1 of the respective colors.

<Inkjet image recording>
(Image formation by UV irradiation)
(Evaluation of multicolor images)
Next, recording on a recording medium was performed using a commercially available inkjet recording apparatus having a piezoelectric inkjet nozzle. The ink supply system was composed of an original tank, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The ink supply tank was insulated and heated from the inkjet head portion.
The temperature sensors were provided near the nozzles of the ink supply tank and the inkjet head, respectively, and temperature control was performed so that the nozzle portions were always 70 ° C. ± 2 ° C.
The piezo-type inkjet head was driven so that 8 to 30 pl multi-size dots could be ejected at a resolution of 720 × 720 dpi. After landing, UV light was condensed to an exposure surface illuminance of 100 mW / cm ² , and the exposure system, main scanning speed, and ejection frequency were adjusted so that irradiation started 0.1 seconds after the ink landed on the recording medium. Further, the exposure time was variable, and exposure energy was irradiated. In the present invention, dpi represents the number of dots per 2.54 cm.

Using each of the color inks prepared above, the ink was ejected in the order of black ink → cyan ink → magenta ink → yellow ink at an environmental temperature of 25 ° C., and ultraviolet light was irradiated for each color by a metal halide lamp Vzero085 manufactured by Integration Technology. The exposure was performed at a total exposure energy of 100 mJ / cm ² uniformly for each color as energy for complete curing so that tackiness disappeared by palpation. As recording media, each color image was recorded on a grained aluminum support, a transparent biaxially stretched polypropylene film having a printability, a soft vinyl chloride sheet, cast coated paper, and commercially available recycled paper. However, in both cases, a high-resolution image without dot bleeding was obtained.
Further, even on high-quality paper, the ink was sufficiently cured without causing the ink to turn around, and there was almost no odor due to unreacted monomers.
Further, the ink recorded on the film had sufficient flexibility, and the ink was not cracked even when it was bent, and there was no problem in the adhesion test by peeling the cello tape (registered trademark).

[Example 2]
(Preparation of cationically polymerizable ink)
<Magenta ink 2>
In the magenta ink 1 prepared in Example 1, among the monomers used as the polymerizable compound, 22 parts by mass of the specific polymerizable compound (a-1) was changed to 27 parts by mass of the following specific polymerizable compound (a-2). A magenta ink 2 was prepared in the same manner as the magenta ink 1 except that.

[Example 3]
(Preparation of cationically polymerizable ink)
<Magenta ink 3>
In the magenta ink 1 prepared in Example 1, among the monomers used as the polymerizable compound, the magenta ink was changed except that the specific polymerizable compound (a-1) was changed to the following specific polymerizable compound (a-3). In the same manner as in Example 1, Magenta Ink 3 was prepared.

[Example 4]
(Preparation of cationically polymerizable ink)
<Magenta ink 4>
In the magenta ink 1 prepared in Example 1, among the monomers used as the polymerizable compound, 22 parts by mass of the specific polymerizable compound (a-1) was changed to 22 parts by mass of the following specific polymerizable compound (a-4). A magenta ink 4 was prepared in the same manner as the magenta ink 1 except that.

[Example 5]
(Preparation of cationically polymerizable ink)
<Magenta ink 5>
・ C. I. Pigment Red 57: 1 5 parts by mass, photocationic polymerization initiator: triphenylsulfonium salt (UVI-6992, manufactured by Dow Chemical Co.) 6 parts by mass, sensitizing dye: 3,10 parts by mass of 9,10-dibutoxyanthracene, polymerization Monomer: 3,4-epoxycyclohexylmethyl-
3 ', 4'-epoxycyclohexanecarboxylate (Celoxide 2021A: manufactured by Daicel UC) 35 parts by weight Monomer: 3-ethyl-3-hydroxymethyloxetane (OXT-101: manufactured by Toagosei Co., Ltd.) 21 parts by weight monomer : 3,7-bis (3-oxetanyl) -5-oxanonane (OXT-221: manufactured by Toagosei Co., Ltd.) 27 parts by mass Monomer: specific polymerizable compound (a-5) (the following structure) 3 parts by mass

[Example 6]
(Preparation of cationically polymerizable ink)
<Magenta ink 6>
・ C. I. Pigment Red 57: 1 5 parts by mass, photocationic polymerization initiator: triphenylsulfonium salt (UVI-6992, manufactured by Dow Chemical Co.) 6 parts by mass, sensitizing dye: 3,10 parts by mass of 9,10-dibutoxyanthracene, polymerization Monomer: 3,4-epoxycyclohexylmethyl-
3 ′, 4′-epoxycyclohexanecarboxylate (Celoxide 2021A: manufactured by Daicel UCB) 35 parts by weight Monomer: 3-ethyl-3-hydroxymethyloxetane (OXT-101: manufactured by Toagosei Co., Ltd.) 16 parts by weight monomer : 3,7-bis (3-oxetanyl) -5-oxanonane (OXT-221: manufactured by Toagosei Co., Ltd.) 27 parts by mass Monomer: specific polymerizable compound (a-6) (the following structure) 2 parts by mass

[Example 7]
(Preparation of cationically polymerizable ink)
<Magenta ink 7>
In magenta ink 1 prepared in Example 1, 3 parts by mass of “9,10-dibutoxyanthracene” used as the sensitizing dye was changed to 3 parts by mass of “Darocur ITX (manufactured by Ciba Specialty Chemicals)”. A magenta ink 7 was prepared in the same manner as the magenta ink 1.

[Example 8]
(Preparation of cationically polymerizable ink)
<Magenta ink 8>
In magenta ink 1 prepared in Example 1, 6 parts by mass of triphenylsulfonium salt (UVI-6992, manufactured by Dow Chemical Co.) used as a photocationic polymerization initiator was used as a photoacid generator: the exemplified compound (b) -39) Magenta ink 8 was prepared in the same manner as magenta ink 1 except that the amount was changed to 6 parts by mass.

[Comparative Example 1]
(Preparation of cationically polymerizable ink)
<Magenta ink 9>
In the magenta ink 1 prepared in Example 1, among the monomers used as the polymerizable compound, 27 parts by mass of the specific polymerizable compound (a-1) was added to 3,7-bis (3-oxetanyl) -5-oxanonane ( OXT-221: manufactured by Toagosei Co., Ltd.) Magenta ink 9 was prepared in the same manner as magenta ink 1 except that the amount was changed to 27 parts by mass.
[Comparative Example 2]
(Preparation of cationically polymerizable ink)
<Magenta ink 10>
In the magenta ink 1 prepared in Example 1, among the monomers used as the polymerizable compound, 27 parts by mass of the specific polymerizable compound (a-1) was changed to 27 parts by mass of the monomer having the following structure. Magenta ink 10 was prepared in the same manner as ink 1.

The crude magenta inks prepared in Examples 2 to 8 and Comparative Examples 1 and 2 were each filtered through a filter having an absolute filtration accuracy of 2 μm to obtain magenta inks 2 to 10.
In addition, in the ink compositions prepared in the above Examples and Comparative Example 1, the ink viscosity at the ink discharge temperature (here, 40 ° C.) was in the range of 7 to 30 mPa · s. When the viscosity at room temperature (25 ° C.) was measured, the magenta ink 1 prepared in Example 1 was 25 mPa · s, whereas n in the general formula (1) was 15 outside the scope of the present invention. In the magenta ink 10 prepared in Comparative Example 2 using a polymerizable compound, it is 110 mPa · s, and n is within the range of the present invention, so that the viscosity of the ink composition at room temperature is excellent in handling properties. It can be seen that

<Inkjet image recording>
(Image formation by UV irradiation)
Using the magenta inks 2 to 10 of Examples 2 to 7 and Comparative Examples 1 and 2 prepared as described above and the magenta ink 1 prepared in Example 1, the same method as described in Example 1 was used. A magenta image was produced.

<Evaluation of inkjet image>
For each formed image, the sensitivity required for curing, odor, ink bleeding on a grained aluminum support, adhesion, printing durability, and storage stability were evaluated according to the methods described below. .

(Measurement of curing sensitivity)
The amount of exposure energy (mJ / cm ² ) that eliminates stickiness on the image surface after UV irradiation was defined as curing sensitivity. The smaller the value, the higher the sensitivity.

(Evaluation of odor)
The image printed on commercially available recycled paper was evaluated for odor according to the following criteria.
○: Almost no penetration and no odor derived from the polymerization initiator Δ: Slight penetration and slight odor derived from the polymerization initiator is also observed ×: Clearly the ink penetrates to the back side and the polymerization initiator Strong odor derived from

(Evaluation of ink bleeding on grained aluminum support)
For images printed on a grained aluminum support, ink bleeding was evaluated according to the following criteria.
○: No blur between adjacent dots Δ: Slightly blur dots ×: Dot blurs and the image is clearly blurred

(Evaluation of adhesion in grained aluminum support)
For the printed image obtained above, a sample that does not scratch the printed surface at all, and in accordance with JIS K 5400, make 11 cuts on the printed surface at 1 mm intervals vertically and horizontally, and a 1 mm square board Samples with 100 eyes were prepared, cellotape (registered trademark) was affixed on each print surface, quickly peeled off at an angle of 90 degrees, and the remaining print images or grids remaining without peeling: Evaluation was performed according to
○: No peeling of the printed image was observed even in the cross cut test. Δ: Some ink peeling was observed in the cross cut test, but almost no peeling was observed unless the ink surface was scratched. Easy to peel off with cello tape (registered trademark)

(Evaluation of printing durability)
Relative comparison using the image printed on the grained aluminum support prepared above as a printing plate, after printing with a Heidel KOR-D machine, using the number of finished sheets as an index of printing durability and the number of sheets of Example 1 as 100 did. A larger numerical value is preferable because it has a higher printing durability.

(Evaluation of storage stability)
The prepared ink was stored at 75% RH and 60 ° C. for 3 days, then the ink viscosity at the ejection temperature was measured, and the increase in the ink viscosity was expressed as the viscosity ratio after storage / before storage. It was judged that the storage stability was good when the viscosity did not change and was close to 1.0, and when it was less than 1.5, the storage stability was determined.
The evaluation results are shown in Table 1 below.

As is apparent from Table 1, the ink compositions of Examples 1 to 8 prepared using the curable composition of the present invention are cured with high sensitivity by ultraviolet irradiation, and form a sharp image without ink bleeding. It was excellent in storage stability and adhesion to the recording medium, and showed practically sufficient printing durability even when a lithographic printing plate was produced. Moreover, by contrast with Examples 1-5 and Examples 6 and 7, when using a specific polymerizable compound having three or more cyclic ether moieties, compared to using a compound having two cyclic ether moieties, It can be seen that further improvement is seen in curing sensitivity and printing durability (film strength). Similarly, the comparison between Example 1 and Example 8 shows that when a compound having a tri (chlorophenyl) sulfonium salt structure is used as the photoacid generator, the curing sensitivity is further improved.
From Comparative Example 2, the viscosity of the composition increases when a compound having a partial structure similar to that of the specific polymerizable compound is used, but the chain length of n is too long and is outside the scope of the present invention. As a result, it was found that the handling property was lowered.

[Example 9]
(Image formation by light emitting diode (LED))
Inkjet image in the same manner as in Example 1 except that the magenta ink 1 prepared in Example 1 was used, and an ultraviolet light emitting diode (UV-LED) was used instead of the metal halide lamp Vzero085 manufactured by Integration Technology. Recorded.
In this embodiment, NCCU033 manufactured by Nichia Corporation was used as the UV-LED. The LED outputs ultraviolet light having a wavelength of 365 nm from one chip. When a current of about 500 mA is applied, light of about 100 mW is emitted from the chip. A plurality of these are arranged at intervals of 7 mm, and a power of 0.3 W / cm ² is obtained on the surface of the recording medium (hereinafter also referred to as a medium). The exposure time after the droplet ejection and the exposure time can be changed according to the transport speed of the medium and the distance between the head and the LED in the transport direction. In this embodiment, the exposure is performed about 0.5 seconds after landing.
The exposure energy on the medium can be adjusted between 0.01 and 15 J / cm ² depending on the setting of the distance to the medium and the conveyance speed.

[Comparative Example 3]
(Image formation by light emitting diode (LED))
Inkjet image recording was performed in the same manner as in Example 9 except that in Example 8, instead of magenta ink 1, magenta ink 9 prepared in Comparative Example 1 was used.

<Evaluation of inkjet image>
For each formed image, in accordance with the method described above, sensitivity required for curing, permeability in commercially available recycled paper, ink bleeding on grained aluminum support, adhesion, printing durability, storage stability Was evaluated in the same manner as in Examples 1 to 7 and Comparative Example 1. The evaluation results are shown in Table 2.

  Along with the results of Example 9, the results of Example 1 in which the image was cured using an ultraviolet lamp (metal halide lamp) using the magenta ink of Example 1 previously implemented are also shown. As in Example 9, when the image was cured with an ultraviolet light-emitting diode, it was higher than the irradiation with radiation while maintaining the image forming property of high printing durability in comparison with the case of using an ultraviolet lamp. It turns out that it becomes sensitivity.

Claims (5)

A polymerizable compound selected from the following compound group having two or more partial structures containing a cyclic ether having a 4-membered ring or more in the molecule and a cationic polymerizable compound having a structure different from that of the polymerizable compound An ink composition comprising a curable composition and a colorant contained in a range of 10: 1 to 10: 100.
Content ratio of a polymerizable compound selected from the group of compounds having two or more partial structures containing a cyclic ether having a 4-membered ring or more in the molecule and a cationic polymerizable compound having a structure different from that of the polymerizable compound The ink composition according to claim 1, wherein is in the range of 10: 3 to 10:80 on a mass basis. Content ratio of a polymerizable compound selected from the group of compounds having two or more partial structures containing a cyclic ether having a 4-membered ring or more in the molecule and a cationic polymerizable compound having a structure different from that of the polymerizable compound The ink composition according to claim 1, wherein is in the range of 10: 5 to 10:60 on a mass basis. The ink composition according to any one of claims 1 to 3, further comprising a compound that generates an acid upon irradiation with radiation. (A) a polymerizable compound selected from the following compound group having two or more partial structures containing a cyclic ether having a 4-membered ring or more in the molecule, and (a-2) cationic polymerization having a structure different from that of the polymerizable compound. (B) a compound that generates an acid upon irradiation with radiation, and (c) a mass ratio of (a) :( a-2) in the range of 10: 3 to 10:80 An ink jet recording method comprising: ejecting an ink composition containing a colorant onto a recording medium by an ink jet recording apparatus; and curing the ink composition by irradiating the ejected ink composition with actinic radiation. .