JP2008274217A - Ink composition, and image-recording method and image-recorded matter obtained using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition suitable for inkjet recording applications that is excellent in dispersibility and dispersion stability of fine pigments, can form an image of high image quality having clear color tones and high coloring power and is curable by irradiation with an active radiation. <P>SOLUTION: The ink composition comprises at least a polymerizable compound, a pigment and a polymer containing a recurring unit derived from a monomer represented by general formula (1) (wherein R<SP>1</SP>is a hydrogen atom or an alkyl group; R<SP>2</SP>and R<SP>3</SP>are each a monovalent substituent group, and R<SP>2</SP>and R<SP>3</SP>may be linked together to form a ring structure; W is any one of -CO-, -C(=O)O-, -CONR-, -OC(=O)- and a phenylene group; R is a hydrogen atom, an alkyl group, an aryl group or an aralkyl group; and X is a single bond or a bivalent linking group). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides a colorant having good dispersibility, excellent color development, can be cured by irradiation with actinic radiation, and can form a high-quality image. The present invention relates to an image recording method and an image recorded matter using the same.

  As an image recording method for forming an image on a recording medium such as paper based on an image data signal, an electrophotographic method, a sublimation / melting thermal transfer method, an ink jet method, and the like are known. Among these, the ink jet method can be implemented with an inexpensive apparatus, and the ink is efficiently used because it forms an image directly on a recording medium by ejecting ink only to a required image portion. The running cost is low, the noise is low, and the image recording method is excellent. According to the inkjet method, printing is possible not only on plain paper but also on non-water-absorbing recording media such as plastic sheets and metal plates, but speeding up and high image quality are important issues when printing. In addition, the time required for drying and curing the droplets after printing has a property of greatly affecting the sharpness of the image.

As one of the ink jet methods, there is a recording method using a curable ink composition for ink jet recording which can be cured by irradiation with actinic radiation. According to this method, a sharp image can be formed by irradiating with radiation immediately after printing and curing the ink droplets.
The curable ink composition is required to have high pigment dispersibility and stability over time in order to form a high-definition image having excellent color developability. Generally, in order to give a clear color tone and high coloring power to an ink composition, it is essential to make the pigment finer. In particular, in an ink composition for ink jet recording, the ejected ink droplets have a sharpness of the image. Therefore, it is indispensable to use a small amount of droplets that are smaller than the thickness of the ink cured film formed by the ink composition. Thus, if the pigment is made finer in order to obtain high coloring power, it becomes difficult to disperse the pigment, resulting in the formation of a pigment aggregate. When the pigment dispersant is added, the viscosity of the ink composition The problem of rising. The occurrence of pigment aggregates and the increase in the viscosity of the ink composition both adversely affect the ink ejection properties and cause a significant decrease in the performance of the ink composition. Further, the ink composition used in the ink jet method is housed in a cartridge, heated during ejection, and cooled during non-ejection and storage, and therefore undergoes repeated heating-cooling temperature changes. There is a problem that the dispersibility is adversely affected, the dispersibility of the pigment is lowered with time, and viscosity and aggregation are likely to occur.

For this reason, there is a need for an ink composition that has sufficient fluidity, stably disperses the finely divided pigment, and is excellent in the temporal dispersion stability of the pigment dispersion. Various proposals have been made on dispersants for obtaining pigment dispersions.
For example, an ink composition using a pigment derivative as a dispersant (see Patent Documents 1 and 2), a specific group such as phthalocyanine or quinacridone to improve the affinity with the pigment, a basic group as a dispersant. An ink composition using a polymer having a polymer (see Patent Document 3), a dispersant such as poly (ethyleneimine) -poly (12-hydroxystearic acid) graft polymer, and a specific monomer that dissolves the dispersant; An ink composition that does not use an organic solvent (see Patent Document 4) has been proposed.
However, in the case of these ink compositions, although the pigment dispersion stability is improved by the function of the dispersant as compared with the prior art, the fineness of the pigment used is insufficient, and further fine pigment particles There is room for improvement in the effect of improving the dispersibility, and there is a problem that the dispersion stability after a long period of time or after repeated temperature changes is not sufficient.
JP 2003-119414 A JP 2004-18656 A JP 2003-321628 A JP 2004-131589 A

  The problem to be solved by the present invention is to solve the above-mentioned problems and achieve the following objects. That is, the present invention is excellent in dispersibility and stability of fine pigments, can form high-quality images with clear color tone and high coloring power, and can be cured by irradiation with actinic radiation. It is an object of the present invention to provide an ink composition suitable for use, and a high-quality image recording method and image recording material using the ink composition.

前記一般式（１）において、Ｒ^１は、水素原子又はアルキル基を表す。Ｒ^２及びＲ^３は、一価の置換基を表す。また、Ｒ^２とＲ^３とが連結して環状構造を形成してもよい。Ｗは、−ＣＯ−、−Ｃ（＝Ｏ）Ｏ−、−ＣＯＮＲ−、−ＯＣ（＝Ｏ）−、及びフェニレン基のいずれかを表す。Ｒは、水素原子、アルキル基、アリール基、又はアラルキル基を表す。Ｘは、単結合又は２価の連結基を表す。
前記＜１＞に記載のインク組成物においては、外部から刺激（熱、光など）により、前記重合性化合物が重合反応を生じ、その結果、硬化する。このため、該インク組成物を用いて記録した画像は、色調が鮮明であり、着色力が高く、高画質である。
＜２＞ 一般式（１）において、Ｒ^１が水素原子又はメチル基を表し、Ｒ^２及びＲ^３が置換基を有していてもよいアルキル基、アリール基又はヘテロ環基を表す前記＜１＞に記載のインク組成物である。
＜３＞ 重合体が、末端にエチレン性不飽和２重結合を有する重合性オリゴマー（マクロモノマー）を共重合単位として更に含むグラフト共重合体である前記＜１＞から＜２＞のいずれかに記載のインク組成物である。
＜５＞ 重合開始剤を含む前記＜１＞から＜４＞のいずれかに記載のインク組成物である。
＜６＞ 重合性化合物がラジカル重合性化合物であり、重合開始剤が光ラジカル発生剤である前記＜５＞に記載のインク組成物である。
＜７＞ 重合性化合物がカチオン重合性化合物であり、重合開始剤が光酸発生剤である前記＜５＞に記載のインク組成物である。
＜８＞ インクジェット用インク組成物である前記＜１＞から＜７＞のいずれかに記載のインク組成物である。
＜９＞ 活性エネルギー線の照射により硬化可能である前記＜１＞から＜８＞のいずれかに記載のインク組成物である。
＜１０＞ 前記＜１＞から＜９＞のいずれかに記載のインク組成物を被記録媒体に印字する印字工程、及び、印字されたインク組成物に活性放射線を照射して該インク組成物を硬化させる硬化工程を含むことを特徴とする画像記録方法である。
＜１１＞ 前記＜１＞から＜１０＞のいずれかに記載のインク組成物を硬化させてなることを特徴とする画像記録物である。
＜１２＞ 被記録媒体上に、インク組成物をインクジェットプリンターにより印字した後、活性放射線を照射してインク組成物を硬化させてなる前記＜１１＞に記載の画像記録物である。 As a result of intensive investigations by the present inventors in order to solve the above problems, when a specific graft polymer is used as a pigment dispersant, it is excellent in pigment dispersibility, and after long-term storage and repeated temperature changes. However, it has been found that an ink composition in which a decrease in dispersion stability is effectively suppressed can be obtained. The present invention is based on the knowledge of the present inventors, and means for solving the above problems are as follows. That is,
<1> An ink composition comprising at least a polymerizable compound, a pigment, and a polymer containing a repeating unit derived from a monomer represented by the following general formula (1).

In the general formula (1), R ¹ represents a hydrogen atom or an alkyl group. R ² and R ³ represent a monovalent substituent. R ² and R ³ may be linked to form a cyclic structure. W represents any of —CO—, —C (═O) O—, —CONR—, —OC (═O) —, and a phenylene group. R represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group. X represents a single bond or a divalent linking group.
In the ink composition according to <1>, the polymerizable compound undergoes a polymerization reaction due to external stimulation (heat, light, etc.), and as a result, is cured. For this reason, an image recorded using the ink composition has a clear color tone, high coloring power, and high image quality.
<2> In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ represent an alkyl group, an aryl group, or a heterocyclic group which may have a substituent. >.
<3> The polymer according to any one of <1> to <2>, wherein the polymer is a graft copolymer further including a polymerizable oligomer (macromonomer) having an ethylenically unsaturated double bond at a terminal as a copolymerization unit. It is an ink composition as described.
<5> The ink composition according to any one of <1> to <4>, including a polymerization initiator.
<6> The ink composition according to <5>, wherein the polymerizable compound is a radical polymerizable compound, and the polymerization initiator is a photoradical generator.
<7> The ink composition according to <5>, wherein the polymerizable compound is a cationic polymerizable compound, and the polymerization initiator is a photoacid generator.
<8> The ink composition according to any one of <1> to <7>, which is an inkjet ink composition.
<9> The ink composition according to any one of <1> to <8>, which is curable by irradiation with active energy rays.
<10> A printing step of printing the ink composition according to any one of <1> to <9> on a recording medium, and irradiating the printed ink composition with actinic radiation to form the ink composition An image recording method comprising a curing step of curing.
<11> An image recorded matter obtained by curing the ink composition according to any one of <1> to <10>.
<12> The image recording material according to <11>, wherein the ink composition is printed on an ink-jet printer on a recording medium, and then the active ink is irradiated to cure the ink composition.

  According to the present invention, the above-described problems can be solved and the above-mentioned problems can be solved, and a high-quality image having excellent dispersibility and stability of fine pigments and having a clear color tone and high coloring power. And an ink composition suitable for inkjet recording applications, which can be cured by irradiation with actinic radiation, and a high-quality image recording method and an image recording material using the ink composition. it can.

(Ink composition, image recording method and recorded image)
The ink composition of the present invention comprises (A) a polymerizable compound, (B) a pigment, and (C) a polymer containing a repeating unit derived from the monomer represented by the general formula (1) (hereinafter referred to as “general formula”). (Sometimes referred to as “derived polymer”), and further contains other components appropriately selected as necessary. The ink composition is curable when irradiated with active energy rays.

  The active energy ray is not particularly limited and may be appropriately selected depending on the purpose as long as it can impart energy capable of generating a starting species of a curing reaction in the ink composition by irradiation. Examples thereof include α rays, γ rays, X rays, ultraviolet rays, visible rays, and electron beams. In the present invention, among these, ultraviolet rays and electron beams are preferable, and ultraviolet rays are particularly preferable from the viewpoint of curing sensitivity and device availability.

The image recording method of the present invention includes a printing step of printing the ink composition of the present invention on a recording medium, and a curing step of irradiating the printed ink composition with active radiation to cure the ink composition. In addition, other processes appropriately selected as necessary are included. The recorded image of the present invention is obtained by curing the ink composition of the present invention.
Hereinafter, the content of the ink composition of the present invention will be described, and the content of the image recording method and the image recorded product of the present invention will also be described.

<(C) Polymer derived from general formula (1)>
The polymer (C) derived from the general formula (1) (hereinafter sometimes simply referred to as “C component”) is a polymer containing a repeating unit derived from the monomer represented by the following general formula (1). It is. In the present invention, the component C functions or functions as a pigment dispersant, and has a structure having a triazine ring having a high flatness and a large π plane. Is a polymer compound having a specific repeating structural unit, and includes the C component due to the steric repulsion effect of the polymer chain. The ink composition of the present invention is excellent in dispersion stability.

In the general formula (1), R ¹ represents a hydrogen atom or a substituted or unsubstituted alkyl group.
As carbon number of the said alkyl group, 1-12 are preferable, 1-8 are more preferable, and 1-4 are especially preferable.
Specific examples of the alkyl group include methyl group, ethyl group, propyl group, n-butyl group, i-butyl group, t-butyl group, n-hexyl group, cyclohexyl group, 2-hydroxyethyl group, 3-hydroxy group. A propyl group, 2-hydroxypropyl group, 2-methoxyethyl group, etc. are mentioned. Among these, a hydrogen atom and a methyl group are preferable.

In the general formula (1), R ² and R ³ represent a monovalent substituent.
Examples of the monovalent substituent include an alkyl group, aryl group, halogen atom, alkoxy group, aryloxy group, alkylthio group, arylthio group, alkoxycarbonyl group, acylamino group, carbamoyl group, cyano group, alkylsulfonyl group, Preferable examples include arylsulfonyl group, sulfamoyl group, sulfonylamino group, and heterocyclic group. Among these, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acylamino group, a sulfonylamino group, and a heterocyclic group are preferable, and a hydrogen atom, an alkyl group, an aryl group, and a heterocyclic ring are preferable. Groups are more preferred.
R ² and R ³ may further have a substituent. Examples of the substituent include the alkyl group, the aryl group, the heterocyclic group, and the alkoxy group (methoxy, ethoxy, isopropoxy, etc.). , The aryloxy group (phenoxy, etc.), halogen (fluorine, chlorine, bromine, etc.), the cyano group, the alkylthio group, the arylthio group, an amino group, and the like.

As carbon number of the alkyl group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Examples of the alkyl group include methyl group, ethyl group, butyl group, hexyl group, octyl group, 2-ethylhexyl group, 3,5,5-trimethylhexyl group, dodecyl group, octadecyl group, benzyl group, (4- Ethoxyphenyl) methyl group, N, N-diethylcarbamoylmethyl group, N, N-dibutylcarbamoylmethyl group, 1- (N, N-dibutylcarbamoyl) ethyl group, 2-methoxyethyl group, 1-methyl-2-phenoxy Ethyl group, (4-chlorophenyl) methyl group, (2,4-dichlorophenyl) methyl group are preferred, ethyl group, butyl group, hexyl group, benzyl group, N, N-diethylcarbamoylmethyl group, N, N-dibutylcarbamoylmethyl 1- (N, N-dibutylcarbamoyl) ethyl group, 1-methyl-2-phenoxyethyl group, (4- Rofeniru) methyl group, (e.g., 2,4-dichlorophenyl) methyl group are preferably exemplified.

Examples of ^R 2, the carbon number of the aryl group represented by ^{R 3,} 6 to 30 are preferred, from 1 to 20 is more preferable. Examples of the aryl group include a phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-phenylphenoxy group, 4-chlorophenyl group, 2-methoxyphenyl group, and 3-ethoxyphenyl. Group, 4-butoxyphenyl group, 2,4-diethoxyphenyl group, 2,5-dibutoxyphenyl group, 4-phenoxyphenyl group, naphthyl group, 4-dibutylcarbamoylphenyl group, 4-dibutylsulfamoylphenyl group Etc. are preferable. Among these, a phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-chlorophenyl group, 2-methoxyphenyl group, 3-ethoxyphenyl group, and 4-butoxyphenyl group are particularly preferable. .

Suitable examples of the halogen atom represented by R ² or R ³ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom and a chlorine atom are particularly preferable.
As carbon number of the alkoxy group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Examples of the alkoxy group include methoxy, ethoxy, propoxy, butoxy, hexyloxy, 2-ethylhexyloxy, 3,5,5-trimethylhexyloxy, octyloxy, decyloxy, 2- Preferable examples include phenoxyethoxy group, 2- (3,5-di-t-butylphenoxy) ethoxy group, dibutylcarbamoylmethoxy group, hexadecyloxy group, octadecyloxy group and the like. Among these, methoxy group, ethoxy group, butoxy group, hexyloxy group, 2-ethylhexyloxy group, 3,5,5-trimethylhexyloxy group, 2-phenoxyethoxy group, and dibutylcarbamoylmethoxy group are particularly preferable.

Examples of ^R 2, the carbon number of the aryl group represented by ^{R 3,} 6 to 30 is preferable, 6 to 20 is more preferable. Examples of the aryloxy group include phenoxy group, tolyloxy group, 4-chlorophenyloxy group, 4-acetamidophenyloxy group, 2-butoxyphenyloxy group, 2-benzoylaminophenyloxy group, and 2,5-dimethoxy-4. -Nitrophenyloxy group and 3-octyloxyphenyloxy group are preferred, and further phenoxy group, tolyloxy group, 4-chlorophenyloxy group, 4-acetamidophenyloxy group, 2-butoxyphenyloxy group, 2,5-dimethoxy-4 -Nitrophenyloxy group etc. are mentioned suitably.

As carbon number of the alkylthio group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Examples of the alkylthio group include methylthio group, ethylthio group, butylthio group, hexylthio group, 2-ethylhexylthio group, 3,5,5-trimethylhexylthio group, octylthio group, decylthio group, 2-phenoxyethylthio group, Preferred examples include 2- (3,5-di-t-butylphenoxy) ethylthio group, dibutylcarbamoylmethylthio group, hexadecylthio group, octadecylthio group and the like. Among these, a methylthio group, an ethylthio group, a butylthio group, a hexylthio group, a 2-ethylhexylthio group, a 3,5,5-trimethylhexylthio group, a 2-phenoxyethylthio group, and a dibutylcarbamoylmethylthio group are preferable.

As carbon number of the arylthio group represented by said R < ² >, R < ³ >, 6-30 are preferable and 6-20 are more preferable. Examples of the arylthio group include a phenylthio group, a tolylthio group, a 4-chlorophenylthio group, a 4-acetamidophenylthio group, a 2-butoxyphenylthio group, a 2-benzoylaminophenylthio group, and 2,5-dimethoxy-4- Preferable examples include a nitrophenylthio group and a 3-octyloxyphenylthio group. Among these, a phenylthio group, a tolylthio group, a 4-chlorophenylthio group, a 4-acetamidophenylthio group, a 2-butoxyphenylthio group, and a 2,5-dimethoxy-4-nitrophenylthio group are preferable.

As carbon number of the alkoxycarbonyl group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Examples of the alkoxycarbonyl group include methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, hexyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, 3,5,5-trimethylhexyloxycarbonyl group, octyl Oxycarbonyl group, decyloxycarbonyl group, 2-phenoxyethoxycarbonyl group, 2- (3,5-di-t-butylphenoxy) ethoxycarbonyl group, dibutylcarbamoylmethoxycarbonyl group, hexadecyloxycarbonyl group, octadecyloxycarbonyl group Etc. are preferable. Among these, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, hexyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, 3,5,5-trimethylhexyloxycarbonyl group, 2-phenoxyethoxycarbonyl group, dibutylcarbamoylmethoxy A carbonyl group is particularly preferred.

As carbon number of the acylamino group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Examples of the acylamino group include formylamino group, acetylamino group, butyrylamino group, lauroylamino group, benzoylamino group, toluoylamino group, phenoxyacetyl group, (4-methoxyphenoxy) acetyl group, 2 ′, 4 Preferred examples include a '-dichlorobenzoylamino group, 2', 4'-di-t-amylbenzoylamino group, acetylmethylamino group, benzoylmethylamino group, and acetylbenzylamino group. Among these, acetylamino group, butyrylamino group, benzoylamino group, toluoylamino group, phenoxyacetyl group, 2 ′, 4′-di-t-amylbenzoylamino group, acetylmethylamino group, benzoylmethylamino group, An acetylbenzylamino group is particularly preferred.

As carbon number of the carbamoyl group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Examples of the carbamoyl group include carbamoyl group, N-phenylcarbamoyl group, N-butylcarbamoyl group, N-octylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-diethylcarbamoyl group, N, N-dibutyl Rucarbamoyl group, N, N-dihexylcarbamoyl group, N, N-diphenylcarbamoyl group, N-methyl-N-phenylcarbamoyl group, N-ethyl-N-phenylcarbamoyl group, N-methyl-N-tolylcarbamoyl, morpholinocarbonyl Preferred examples include a group, piperidinocarbonyl group, N, N-bis (2-methoxyethyl) carbamoyl group and the like. Among these, N-butylcarbamoyl group, N-octylcarbamoyl group, N-phenylcarbamoyl group, N, N-diethylcarbamoyl group, N, N-dibutylcarbamoyl group, and N-methyl-N-phenylcarbamoyl group are particularly preferable. .

As carbon number of the alkylsulfonyl group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Preferable examples of the alkylsulfonyl group include a methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl group, a hexylsulfonyl group, and a benzylsulfonyl group. Among these, a methylsulfonyl group and a benzylsulfonyl group are particularly preferable.

As carbon number of the arylsulfonyl group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Preferred examples of the arylsulfonyl group include a phenylsulfonyl group, a 4-methylphenylsulfonyl group, a naphthylsulfonyl group, a 4-methoxysulfonyl group, and a 4-chlorophenylsulfonyl group. Among these, a methylsulfonyl group, a phenylsulfonyl group, and a 4-methylphenylsulfonyl group are particularly preferable.

As carbon number of the sulfamoyl group represented by said R < ² >, R < ³ >, 1-30 are preferable and 1-20 are more preferable. Examples of the sulfamoyl group include sulfamoyl group, N-phenylsulfamoyl group, N, N-dimethylsulfamoyl group, N, N-diethylsulfamoyl group, N, N-dibutylsulfamoyl group, N , N-dihexylsulfamoyl group, N, N-diphenylsulfamoyl group, N-methyl-N-phenylsulfamoyl group, N-ethyl-N-phenylsulfamoyl group, N-methyl-N-tolyl Preferred examples include a sulfamoyl group, a morpholinosulfonyl group, a piperidinosulfonyl group, and an N, N-bis (2-methoxyethyl) sulfonyl group. Among these, a sulfamoyl group, an N-phenylsulfamoyl group, an N, N-dibutylsulfamoyl group, an N, N-diphenylsulfamoyl group, and an N-methyl-N-phenylsulfamoyl group are particularly preferable.

The heterocyclic group represented by R ² or R ³ may be either saturated or unsaturated, may be benzo-fused, may have a substituent, or 3 A heterocycle having 10 to 10 members is preferable, a heterocycle having 4 to 8 members is more preferable, and a heterocycle having 5 to 7 members is particularly preferable. Examples of the heterocyclic group include oxazole group, thiazole group, imidazole group, pyrazole group, triazole group, isoxazole group, isothiazole group, furan group, thiophene group, pyrrole group, pyridine group, pyrimidine group, and triazine group. Are preferable.

In the general formula (1), W represents —CO—, —C (═O) O—, —CONR—, —OC (═O) —, or a phenylene group.
R represents a hydrogen atom or an alkyl group (for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, n-hexyl group, n-octyl group, 2-hydroxyethyl group, etc.) Represents an aryl group (for example, a phenyl group).

In the general formula (1), X represents a single bond or a divalent linking group.
Examples of the divalent linking group include a linear, branched or cyclic alkylene group, an aralkylene group, and an arylene group. These may further have a substituent.
As carbon number of the said alkylene group, 1-10 are preferable and 1-4 are more preferable. Suitable examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, an octylene group, and a decylene group. Among these, a methylene group, an ethylene group, a propylene group, and the like are preferable.
As carbon number of the said aralkylene group, 7-13 are preferable. Examples of the aralkylene group include a benzylidene group and a cinnamylidene group.
As carbon number of the said arylene group, 6-12 are preferable. Examples of the arylene group include a phenylene group, a cumenylene group, a mesitylene group, a tolylene group, and a xylylene group. Among these, a phenylene group is particularly preferable.
In the divalent linking group, —NR ⁴ —, —NR ⁴ R ⁵ —, —COO—, —OCO—, —O—, —NHCO—, —NHC (═O) NH—, —SO ₂ NH —, —NHSO ₂ —, —NHCOO—, —OCONH—, or a group derived from a heterocyclic ring may be interposed as a linking group. R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group, and preferred examples include hydrogen, a methyl group, an ethyl group, and a propyl group.

  Preferred specific examples (M-1 to M-20) of the monomer represented by the general formula (1) are listed below. The present invention is not limited to these specific examples.

  Preferred specific examples (M-1 to M-20) of the monomer represented by the general formula (1) include, for example, J. Org. Am. Chem. Soc. , 120, 6761-6769 (1998), Adv. Mater. 12, 874-878 (2000), J. MoI. Am. Chem. Soc. 128, 14236-14237 (2006), J. Am. Polym. Sci. A: Polym. Chem. , 43, 4618-4631 (2005), etc., and a known method such as a reaction between an alcohol and an isocyanate, or a reaction between an amine and an isocyanate, if necessary.

In the present invention, the component C is particularly preferably a graft copolymer further containing a polymerizable oligomer having an ethylenically unsaturated double bond as a terminal as a copolymer unit.
Such a polymerizable oligomer having an ethylenically unsaturated double bond at the terminal is also called a macromonomer because it is a compound having a predetermined molecular weight.

The polymerizable oligomer includes a polymer chain portion and a polymerizable functional group portion having an ethylenically unsaturated double bond. The polymerizable functional group having an ethylenically unsaturated double bond is preferably present only at one end of the polymer chain in the polymerizable oligomer from the viewpoint of obtaining a desired graft polymer. .
Preferred examples of the polymerizable functional group having an ethylenically unsaturated double bond include a (meth) acryloyl group and a vinyl group, with a (meth) acryloyl group being particularly preferred.
The molecular weight of the polymerizable oligomer (macromonomer) is preferably a number average molecular weight (Mn) in terms of polystyrene, preferably 1000 to 10,000, and more preferably 2000 to 9000.

  Examples of the polymer chain portion include homopolymers or copolymers formed from at least one monomer selected from the group consisting of alkyl (meth) acrylate, styrene and derivatives thereof, acrylonitrile, vinyl acetate, and butadiene, Preferred examples include polyethylene oxide, polypropylene oxide, polycaprolactone, and the like.

  Preferable examples of the polymerizable oligomer include oligomers represented by the following general formula (2).

However, in the general formula ^{(2), R 11} and ^{R 13} each independently represent a hydrogen atom or a methyl group. R ¹² is an alkylene group having 1 to 12 carbon atoms (preferably an alkylene group having 2 to 4 carbon atoms, which may have a substituent (for example, a hydroxyl group), and further an ester bond, an ether bond, an amide Which may be linked via a bond or the like). Y is a phenyl group, a phenyl group having an alkyl group having 1 to 4 carbon atoms, or —COOR ¹⁴ (where R ¹⁴ is an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a carbon group having 7 to 10 carbon atoms). Represents an arylalkyl group) and is preferably a phenyl group or —COOR ¹⁴ (wherein R ¹⁴ is an alkyl group having 1 to 12 carbon atoms). q is 20-200.

Preferred examples of the polymerizable oligomer (macromonomer) include polymethyl (meth) acrylate, poly-n-butyl (meth) acrylate, poly-i-butyl (meth) acrylate, and one molecular end of polystyrene (meth). Examples thereof include a polymer having an acryloyl group bonded thereto.
Examples of commercially available polymerizable oligomers include, for example, one-end methacryloylated polystyrene oligomer (Mn = 6000, trade name: AS-6, manufactured by Toa Gosei Chemical Co., Ltd.), one-end methacryloylated polymethyl methacrylate oligomer (Mn). = 6000, trade name: AA-6, manufactured by Toa Gosei Chemical Co., Ltd.) and one-end methacryloylated poly-n-butyl acrylate oligomer (Mn = 6000, trade name: AB-6, Toa Gosei Chemical Co., Ltd.) Manufactured).

As the polymerizable oligomer, in addition to the polymerizable oligomer represented by the general formula (2), a polymerizable oligomer represented by the following general formula (3) is also preferable.

In the general formula (3), R ²¹ represents a hydrogen atom or a methyl group. R ²² represents an alkylene group having 1 to 8 carbon atoms, preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 2 to 3 carbon atoms. X ²¹ represents —OR ²³ or OCOR ²⁴ . R ²³ and R ²⁴ represent a hydrogen atom, an alkyl group (preferably an alkyl group having 1 to 18 carbon atoms), or an aryl group (preferably a phenyl group substituted with an alkyl group having 1 to 18 carbon atoms). n represents 2-200, 5-100 are preferable and 10-100 are more preferable.

  Examples of the polymerizable oligomer represented by the general formula (3) include polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol polypropylene glycol mono (meth) acrylate, and polytetramethylene glycol monomethacrylate. Etc. are preferable. These may be commercial products or may be appropriately synthesized.

  As a commercial item of the polymerizable monomer represented by the general formula (3), for example, methoxypolyethylene glycol methacrylate (trade names: NK ester M-40G, M-90G, M-230G (above, Toa Gosei Chemical Industry ( Product name: Blemmer PME-100, PME-200, PME-400, PME-1000, PME-2000, PME-4000 (above, manufactured by NOF Corporation)), polyethylene glycol monomethacrylate (product) Name: BLEMMER PE-90, PE-200, PE-350, manufactured by NOF Corporation, polypropylene glycol monomethacrylate (trade name: BLEMMER PP-500, PP-800, PP-1000, manufactured by NOF Corporation) ), Polyethylene glycol polypropylene glycol monomethacrylate (quotient) Name: Blemmer 70PEP-370B, manufactured by NOF Corporation, polyethylene glycol polytetramethylene glycol monomethacrylate (trade name: BLEMMER 55PET-800, manufactured by NOF Corporation), polypropylene glycol polytetramethylene glycol monomethacrylate (product) Name: BLEMMER NHK-5050, manufactured by NOF Corporation).

In the present invention, the component C is particularly preferably a monomer having a nitrogen atom as a copolymer component.
Examples of the monomer having a nitrogen atom include N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, 1- (N, N-dimethylamino) -1, 1- Dimethylmethyl (meth) acrylate, N, N-dimethylaminohexyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-diisopropylaminoethyl (meth) acrylate, N, N-di-n- Butylaminoethyl (meth) acrylate, N, N-di-i-butylaminoethyl (meth) acrylate, morpholinoethyl (meth) acrylate, piperidinoethyl (meth) acrylate, 1-pyrrolidinoethyl (meth) acrylate, N, N -Methyl-2-pyrrolidylaminoethyl (meth) ac Rate and N, N- methylphenyl aminoethyl (meth) acrylate (or (meth) acrylates);

Dimethyl (meth) acrylamide, diethyl (meth) acrylamide, diisopropyl (meth) acrylamide, di-n-butyl (meth) acrylamide, di-i-butyl (meth) acrylamide, morpholino (meth) acrylamide, piperidino (meth) acrylamide, N-methyl-2-pyrrolidyl (meth) acrylamide and N, N-methylphenyl (meth) acrylamide (above (meth) acrylamides);
2- (N, N-dimethylamino) ethyl (meth) acrylamide, 2- (N, N-diethylamino) ethyl (meth) acrylamide, 3- (N, N-diethylamino) propyl (meth) acrylamide, 3- (N , N-dimethylamino) propyl (meth) acrylamide, 1- (N, N-dimethylamino) -1,1-dimethylmethyl (meth) acrylamide and 6- (N, N-diethylamino) hexyl (meth) acrylamide (above) Aminoalkyl (meth) acrylamides);
p-vinylbenzyl-N, N-dimethylamine, p-vinylbenzyl-N, N-diethylamine, p-vinylbenzyl-N, N-dihexylamine (above vinylbenzylamines);
Examples thereof include 2-vinylpyridine, 4-vinylpyridine, and N-vinylimidazole. Among these, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, 3- (N, N-diethylamino) propyl (meth) acrylamide, 3- (N, N- Preferable examples include dimethylamino) propyl (meth) acrylamide, 2-vinylpyridine, 4-vinylpyridine, N-vinylimidazole, and the like.

The component C may further contain other monomers copolymerizable with these as a copolymerization component.
Examples of the other monomers include unsaturated carboxylic acids (eg, (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid), aromatic vinyl compounds (eg, styrene, α-methylstyrene, vinyl). Toluene, 2-vinylpyridine, 4-vinylpyridine, N-vinylimidazole, etc.), (meth) acrylic acid alkyl ester (eg, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i -Butyl (meth) acrylate), (meth) acrylic acid alkyl aryl ester (eg, benzyl (meth) acrylate), (meth) acrylic acid substituted alkyl ester (eg, glycidyl (meth) acrylate, 2-hydroxyethyl ( Meth) acrylates), carboxylic acid vinyl esters (eg Vinyl acetate and vinyl propionate), vinyl cyanides (e.g., (meth) acrylonitrile and α- chloro acrylonitrile), aliphatic conjugated dienes (e.g., 1,3-butadiene and isoprene), and the like. Among these, unsaturated carboxylic acid, (meth) acrylic acid alkyl ester, (meth) acrylic acid alkyl aryl ester, carboxylic acid vinyl ester and the like are preferable.

The component C is a copolymer comprising a repeating unit derived from the monomer represented by the general formula (1) and a repeating unit derived from the polymerizable oligomer (macromonomer), or the general formula (1 ), A copolymer comprising a repeating unit derived from the polymerizable oligomer (macromonomer), and a repeating unit derived from the monomer having a nitrogen atom. preferable.
In the component C, the ratio of the repeating units derived from the monomer represented by the general formula (1) in all repeating units is preferably 5 to 70% by weight, more preferably 5 to 30% by weight, The ratio of the repeating unit derived from the polymerizable oligomer (macromonomer) is preferably 30 to 95% by weight, more preferably 50 to 90% by weight. The ratio of the repeating unit derived from the monomer having a nitrogen-containing group is 5 to 80% by weight is preferable, and 5 to 50% by weight is more preferable.
When the C component further contains the other monomer copolymerizable therewith, the ratio of the repeating unit derived from the other monomer in the total repeating units is preferably 5 to 30% by weight. .

As a weight average molecular weight (Mw) of the said C component, 1000-200000 are preferable, for example, and 10000-100,000 are more preferable.
The weight average molecular weight (Mw) can be measured, for example, by gel permeation chromatography (carrier: tetrahydrofuran), and is calculated as a polystyrene equivalent weight average molecular weight.

Here, the preferable specific example of the said C component is shown below. The present invention is not limited to these specific examples. In the following specific examples, the compounds displayed before and after “/” mean that they are monomer components constituting the polymer of component C.
1) The above exemplary compound M-1 / terminal methacryloylated polymethyl methacrylate copolymer,
2) Exemplified compound M-2 / terminal methacryloylated polymethyl methacrylate copolymer,
3) Exemplified compound M-4 / terminal methacryloylated polymethyl methacrylate copolymer,
4) The above exemplified compound M-6 / terminal methacryloylated polymethyl methacrylate copolymer,
5) Exemplified compound M-7 / terminal methacryloylated polymethyl methacrylate copolymer,
6) The above exemplary compound M-11 / terminal methacryloylated polymethyl methacrylate copolymer,
7) The above exemplary compound M-1 / terminal methacryloylated polybutyl acrylate copolymer,
8) Exemplified compound M-1 / polyethylene glycol mono (meth) acrylate copolymer,
9) Exemplified compound M-1 / terminal methacryloylated polycaprolactone copolymer,
10) The above exemplary compound M-7 / terminal methacryloylated polycaprolactone copolymer,
11) The above exemplary compound M-9 / polyethylene glycol mono (meth) acrylate copolymer,
12) The above exemplary compound M-1 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethyl methacrylate copolymer,
13) The above exemplary compound M-1 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polybutylacrylate copolymer,
14) The above exemplary compound M-7 / 3- (N, N-dimethylamino) propylacrylamide / terminated methacryloylated polymethyl methacrylate copolymer,
15) The above exemplary compound M-11-3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethyl methacrylate copolymer,
16) Exemplified compound M-13 / 3- (N, N-dimethylamino) propylacrylamide / terminated methacryloylated polymethyl methacrylate copolymer,
17) The above exemplary compound M-17 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethyl methacrylate copolymer,
18) Exemplified compound M-19 / 3- (N, N-dimethylamino) propylacrylamide / terminated methacryloylated polymethyl methacrylate copolymer,
19) The above exemplary compound M-8 / 2- (N, N-dimethylamino) ethyl (meth) acrylate / terminal methacryloylated polymethyl methacrylate / polyethylene glycol mono (meth) acrylate copolymer,
20) The above exemplary compound M-7 / 2-vinylpyridine / terminal methacryloylated polymethyl methacrylate copolymer,
21) The above exemplary compound M-11 / p-vinylbenzyl-N, N-dimethylamine / polyethylene glycol mono (meth) acrylate copolymer,
22) The above exemplary compound M-1 / 2- (N, N-dimethylamino) ethyl methacrylate / terminal methacryloylated poly n-butyl methacrylate copolymer,
23) The above exemplary compound M-1 / styrene / terminal methacryloylated polymethyl methacrylate copolymer,
24) Exemplified compound M-1 / N, N-dimethylacrylamide / terminal methacryloylated polymethyl methacrylate copolymer,
25) Exemplified compound M-2 / methacrylic acid / polyethylene glycol mono (meth) acrylate copolymer,
26) The above exemplary compound M-6 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethyl methacrylate copolymer / polyethylene glycol mono (meth) acrylate copolymer,
27) The above exemplary compound M-11 / 2- (N, N-dimethylamino) ethyl methacrylate / terminal methacryloylated polymethyl methacrylate copolymer,
28) The above exemplary compound M-11-4-vinylpyridine / terminal methacryloylated polymethyl methacrylate copolymer,
29) Exemplified compound M-1 / Exemplary compound N-1 / Terminal methacryloylated polymethyl methacrylate copolymer,
30) Exemplified Compound M-7 / Exemplified Compound N-1 / Terminal Methacryloylated Polymethyl Methacrylate Copolymer,
31) The above exemplary compound M-11 / the following exemplary compound N-1 / terminal methacryloylated polymethyl methacrylate copolymer,
32) Exemplified compound M-1 / Exemplified compound N-1 / 3- (N, N-dimethylamino) propylacrylamide / terminated methacryloylated polymethyl methacrylate copolymer,
33) Exemplified compound M-1 / Exemplified compound N-2 / 3- (N, N-dimethylamino) propylacrylamide / terminated methacryloylated polymethyl methacrylate copolymer,

  Preferable specific examples of the component C described above are all graft polymers, but such graft polymers can be synthesized, for example, as follows. That is, it can be obtained by radical polymerization of the polymerizable oligomer, the monomer having the nitrogen atom-containing group, and the other monomer, which are used in combination as required, in a solvent. In the radical polymerization, a radical polymerization initiator is generally used, but in addition to the radical polymerization initiator, a chain transfer agent (eg, 2-mercaptoethanol and dodecyl mercaptan) may be used.

In the present invention, the component C may be used alone or in combination of two or more.
As content of the said C component in the ink composition of this invention, 1-100 mass% is preferable with respect to the addition amount of the said pigment, and 5-50 mass% is more preferable.
When the content of the component C is less than 1% by mass, the dispersibility may be insufficient, and a dispersion having a large particle size (aggregated) may be obtained. Increase in viscosity due to coalescence may occur.
In addition, in the ink composition of this invention, as long as the effect of this invention is not impaired, in addition to the said C component, a well-known pigment dispersant can be used together. In this case, the content of the known pigment dispersant in the ink composition is preferably 50% by mass or less based on the amount of the component C added.

<(A) Polymerizable compound>
The (A) polymerizable compound (hereinafter, sometimes simply referred to as “component A” or “polymerizable compound”) is a curable compound that causes a polymerization reaction by external stimulation, for example, application of some energy, and is curable. If there is no particular limitation, it can be appropriately selected according to the purpose, and it can be used regardless of the type of monomer, oligomer, or polymer. Various known polymerizable monomers known as photo cationic polymerizable monomers and photo radical polymerizable monomers that cause a polymerization reaction are preferable.

The said polymeric compound may be used individually by 1 type, and may use 2 or more types together in order to adjust reaction rate, ink physical property, cured film physical property, etc.
The polymerizable compound may be a monofunctional compound or a polyfunctional compound.

-Photo cationic polymerizable monomer-
Examples of the photocationically polymerizable monomer that can be used as the polymerizable compound include, for example, JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-2001. Preferred examples include epoxy compounds, vinyl ether compounds, oxetane compounds and the like described in JP-A Nos. 310937 and 2001-220526.

The epoxy compound may be a monofunctional epoxy compound or a polyfunctional epoxy compound.
Examples of the monofunctional epoxy compound include phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, and 1,3-butadiene mono. Oxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3-vinylcyclohexene oxide, etc. Can be mentioned.

Examples of the polyfunctional epoxy compound include 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′-epoxycyclohexanecarboxylate, 2 -(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexyl) Methyl) 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) , Epoxyhexahydrophthalate dioctyl, epoxyhexahydrophthalate di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, Serine triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8-di Examples thereof include epoxy octane, 1,2,5,6-diepoxycyclooctane, and the like.
Among these epoxy compounds, an aromatic epoxy compound and an alicyclic epoxy compound are preferable, and an alicyclic epoxy compound is particularly preferable in terms of excellent curing speed.

The vinyl ether compound may be a monofunctional vinyl ether compound or a polyfunctional vinyl ether compound.
Examples of the monofunctional vinyl ether compound include 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 Ether, 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 compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide di Divinyl ethers such as vinyl ether and bisphenol F alkylene oxide divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pen Tavinyl 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 And polyfunctional vinyl ethers such as tetravinyl ether, propylene oxide-added pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.
Among these vinyl ether compounds, di- or trivinyl ether compounds are preferable and divinyl ether compounds are particularly preferable in terms of curability, adhesion to a recording medium, surface hardness of the formed image, and the like.

The oxetane compound means a compound having an oxetane ring, and preferred examples thereof include known oxetane compounds described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217.
In the present invention, the oxetane compound is preferably a compound having 1 to 4 oxetane rings in its structure. When such a compound is used, it becomes easy to maintain the viscosity of the ink composition in a good handling property range, and it is possible to obtain high adhesion of the cured ink to a recording medium. Is advantageous.

The oxetane compound may be a monofunctional oxetane compound or a polyfunctional oxetane compound.
Examples of the monofunctional oxetane compound include 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, (3-ethyl-3-oxetanylmethoxy) methylbenzene, 4-fluoro -[1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, 4-methoxy- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, [1- (3-ethyl-3-oxetanyl) Methoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl-3-oxetanylmethyl) Ether, 2-ethylhexyl (3-ethyl-3-oxe) Nylmethyl) ether, ethyl diethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, Dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tetrabromophenoxy Ethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether, pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, and the like.

  Examples of the polyfunctional oxetane compound include 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)). Bis- (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1 , 3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether, Triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3 Ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3 -Ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl- 3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3- Til-3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentane Kis (3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A Bis (3-ethyl-3-oxetanylmethyl) ether, EO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis (3 -Ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl) ether, and the like.

In addition to these, as the oxetane compound, compounds described in detail in paragraphs [0021] to [0084] of JP-A-2003-341217 can also be suitably used in the present invention.
Among the oxetane compounds described above, in the present invention, a compound having 1 to 2 oxetane rings is preferable from the viewpoint of viscosity and adhesiveness of the ink composition.

  In the ink composition of the present invention, the polymerizable compounds described above may be used alone or in combination of two or more, but the viewpoint of effectively suppressing shrinkage during ink curing Is preferably used in combination with at least one oxetane compound and at least one compound selected from an epoxy compound and a vinyl ether compound.

-Photo radical polymerizable monomer-
Examples of the radical photopolymerizable monomer that can be used as the polymerizable compound include (meth) acrylates, (meth) acrylamides, aromatic vinyls, and the like. In the present invention, when referring to both or one of “acrylate” and “methacrylate”, “(meth) acryl” when referring to both or one of “acrylic” and “methacrylic” And may be described respectively.

The (meth) acrylates may be monofunctional (meth) acrylates or polyfunctional (meth) acrylates.
Examples of the monofunctional (meth) acrylates include hexyl group (meth) acrylate, 2-ethylhexyl (meth) acrylate, tert-octyl (meth) acrylate, isoamyl (meth) acrylate, decyl (meth) acrylate, isodecyl ( (Meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) Acrylate, 2-ethylhexyl glycol (meth) acrylate, butoxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 4-bromobutyl (meth) acrylate, Noethyl (meth) acrylate, benzyl (meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, alkoxymethyl (meth) acrylate, alkoxyethyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (Meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate, 2,2,2-tetrafluoroethyl (meth) acrylate, 1H, 1H, 2H, 2H perfluorodecyl (meth) acrylate, 4- Butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate Glycidyl (meth) acrylate, glycidyloxybutyl (meth) acrylate, glycidyloxyethyl (meth) acrylate, glycidyloxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyalkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate,

2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate , Dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, trimethoxysilylpropyl (meth) acrylate, trimethylsilylpropyl (meth) acrylate, polyethylene oxide monomethyl ether (meth) acrylate, oligoethylene oxide monomethyl ether (meth) acrylate, Polyethylene oxide (meth) acrylate, oligoethylene oxide (meth) acrylate, oligoethylene oxide Monoalkyl ether (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, dipropylene glycol (meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, oligopropylene oxide monoalkyl ether (meth) acrylate, 2-methacrylate Leuoxytyl succinic acid, 2-methacryloyloxyhexahydrophthalic acid, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, perfluorooctylethyl (meta ) Acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, EO-modified phenol (meth) acrylate, EO-modified acrylate Zole (meth) acrylate, EO-modified nonylphenol (meth) acrylate, PO-modified nonylphenol (meth) acrylate, EO-modified-2-ethylhexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, etc. Is mentioned.

Examples of the polyfunctional (meth) acrylate include bifunctional, trifunctional, tetrafunctional, pentafunctional, and hexafunctional ones.
Examples of the bifunctional (meth) acrylate include 1,6-hexanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and 2,4- Dimethyl-1,5-pentanediol di (meth) acrylate, butylethylpropanediol (meth) acrylate, ethoxylated cyclohexanemethanol di (meth) acrylate, polyethylene glycol di (meth) acrylate, oligoethylene glycol di (meth) acrylate , Ethylene glycol di (meth) acrylate, 2-ethyl-2-butyl-butanediol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, EO-modified bisphenol A di (meth) a Relate, bisphenol F polyethoxydi (meth) acrylate, polypropylene glycol di (meth) acrylate, oligopropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 2-ethyl-2-butylpropanediol di ( (Meth) acrylate, 1,9-nonane di (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, tricyclodecane di (meth) acrylate, dipropylene glycol di (meth) acrylate, propoxylated neopentyl glycol Examples thereof include di (meth) acrylate.

Examples of the trifunctional (meth) acrylate include, for example, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane alkylene oxide-modified tri (meth) acrylate, and pentaerythritol tri (meth). Acrylate, dipentaerythritol tri (meth) acrylate, trimethylolpropane tri ((meth) acryloyloxypropyl) ether, isocyanuric acid alkylene oxide modified tri (meth) acrylate, dipentaerythritol tri (meth) acrylate propionate, tri (( (Meth) acryloyloxyethyl) isocyanurate, hydroxypivalaldehyde-modified dimethylolpropane tri (meth) acrylate, sorbitol tri (meta) Acrylate, propoxylated trimethylolpropane tri (meth) acrylate, ethoxylated glycerin triacrylate, and the like.
Examples of the tetrafunctional (meth) acrylate include pentaerythritol tetra (meth) acrylate, sorbitol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate propionate, and ethoxylation. And pentaerythritol tetra (meth) acrylate.
Examples of the pentafunctional (meth) acrylate include sorbitol penta (meth) acrylate and dipentaerythritol penta (meth) acrylate.
Examples of the hexafunctional (meth) acrylate include dipentaerythritol hexa (meth) acrylate, sorbitol hexa (meth) acrylate, phosphazene alkylene oxide-modified hexa (meth) acrylate, and captolactone-modified dipentaerythritol hexa (meth). Acrylate, and the like.

  Examples of the (meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, Nn-butyl (meth) acrylamide, N-t-butyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (Meth) acrylamide, (meth) acryloylmorpholine, etc. are mentioned.

  Examples of the aromatic vinyls include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid. Methyl ester, 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4- Hexyl styrene, 3-octyl styrene, 4-octyl styrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allyl styrene, isopropenyl styrene, butenyl styrene, octet Rusuchiren, 4-t-butoxycarbonyl styrene, 4-methoxystyrene, 4-t-butoxystyrene, and the like.

  Examples of the radical photopolymerizable monomer further include vinyl esters [vinyl acetate, vinyl propionate, vinyl versatate, etc.], allyl esters [allyl acetate, etc.], halogen-containing monomers [vinylidene chloride, vinyl chloride, etc.] , Vinyl ether [methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxy vinyl ether, 2-ethylhexyl vinyl ether, methoxyethyl vinyl ether, cyclohexyl vinyl ether, chloroethyl vinyl ether, triethylene glycol divinyl ether, etc.], vinyl cyanide [(meth) acrylonitrile, etc.], Olefins [ethylene, propylene, etc.] can also be used.

Among these, (meth) acrylates and (meth) acrylamides are preferable from the viewpoint of curing speed, tetrafunctional or higher (meth) acrylate is more preferable, and polyfunctional (in terms of viscosity of the ink composition). It is preferable to use a combination of (meth) acrylate with monofunctional or bifunctional (meth) acrylate and (meth) acrylamide.
The content of the polymerizable compound in the ink composition is preferably 50 to 95% by mass, more preferably 60 to 92% by mass, and particularly preferably 70 to 90% by mass with respect to the total solid content of the ink composition. preferable.

<(B) Pigment>
The pigment (B) (hereinafter sometimes simply referred to as “B component” or “pigment”) functions as a coloring material of the ink composition. In the present invention, the pigment having a fine particle size is used as the pigment. As a result of being uniformly and stably dispersed in the ink composition by the function of the component C, the ink composition of the present invention is excellent in color developability, and can form a sharp image with excellent weather resistance.
The pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include known organic pigments and inorganic pigments. Resin particles dyed with dyes, commercially available pigment dispersions, The surface-treated pigment (for example, a pigment dispersed in an insoluble resin or the like using a pigment as a dispersion medium, or a pigment grafted with a resin on the pigment surface) can also be used. Examples of the pigment include, for example, “Dictionary of Pigments” (2000), edited by Seijiro Ito. Herbst, K.M. Examples include those described in Hunger “Industrial Organic Pigments”, Japanese Patent Application Laid-Open No. 2002-12607, Japanese Patent Application Laid-Open No. 2002-188025, Japanese Patent Application Laid-Open No. 2003-26978, and Japanese Patent Application Laid-Open No. 2003-342503.

  The yellow pigment is a pigment exhibiting a yellow color. I. Pigment Yellow 1 (Fast Yellow G etc.), C.I. I. Monoazo pigments such as CI Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow, etc.), C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 155, C.I. I. Disazo pigments such as CI Pigment Yellow 219; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Pigment yellow 95 (condensed azo yellow, etc.), C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. Condensed azo pigments such as C.I. Pigment Yellow 166; I. Pigment Yellow 115 (quinoline yellow lake, etc.), etc., acidic dye lake pigments, C.I. I. Basic dye lake pigments such as C.I. Pigment Yellow 18 (such as thioflavine lake); I. Anthraquinone pigments such as C.I. Pigment Yellow 24 (Flavantron Yellow, etc.); I. Quinophthalone pigments such as C.I. Pigment Yellow 110 (e.g., Quinophthalone Yellow); I. Pigment yellow 139 (isoindoline yellow, etc.) and the like, isoindoline pigments such as C.I. I. Pyrazolone pigments such as C.I. Pigment Yellow 60 (Pyrazolone Yellow, etc.); I. Pigment yellow 120, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 167, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. An acetolone pigment such as C.I. Pigment Yellow 194; I. Pigment complex pigments such as CI Pigment Yellow 150, C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.), C.I. I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow and the like).

  The magenta pigment is a pigment exhibiting red or magenta color. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Pigment red 1, C.I. I. Pigment red 4, C.I. I. B-naphthol pigments such as C.I. Pigment Red 6; I. Disazo pigments such as CI Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Pigment Red 57: 1 (Brilliant Carmine 6B etc.), C.I. I. Pigment red 52: 1, C.I. I. Pigment Red 48 (B-oxynaphthoic acid lake, etc.) azo lake pigment, C.I. I. Pigment red 144, C.I. I. Pigment red 166, C.I. I. Pigment red 220, C.I. I. Pigment red 214, C.I. I. Pigment red 221, C.I. I. Condensed azo pigments such as C.I. Pigment Red 242 (condensed azo red and the like), C.I. I. Pigment Red 174 (Phloxine B lake, etc.), C.I. I. Pigment Red 172 (Erythrosin Lake, etc.) and other acidic dye lake pigments, C.I. 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 CI Pigment Red 88 (Thioindigo Bordeaux and the like), C.I. I. Perinone pigments such as CI Pigment Red 194 (perinone red, etc.); I. Pigment red 149, C.I. I. Pigment red 179, C.I. I. Pigment red 178, C.I. I. Pigment red 190, C.I. I. Pigment red 224, C.I. I. Perylene pigments such as CI Pigment Red 123; I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Pigment red 122, C.I. I. Pigment red 262, C.I. I. Pigment red 207, C.I. I. Quinacridone pigments such as CI Pigment Red 209; I. Pigment Red 180 (Isoindolinone Red 2BLT, etc.), etc., isoindolinone pigments, C.I. I. Alizarin lake pigments such as C.I. Pigment Red 83 (Mada Lake, etc.); I. Pigment red 171, C.I. I. Pigment red 175, C.I. I. Pigment red 176, C.I. I. Pigment red 185, C.I. I. Naphtholone pigments such as CI Pigment Red 208; I. Naphthol AS-based lake pigments such as CI Pigment Red 247; I. Pigment red 2, C.I. I. Pigment red 5, C.I. I. Pigment red 21, C.I. I. Pigment red 170, C.I. I. Pigment red 187, C.I. I. Pigment red 256, C.I. I. Pigment red 268, C.I. I. Naphthol AS pigments such as C.I. Pigment Red 269; I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. And diketopyrrolopyrrole pigments such as CI Pigment Red 272.

  The cyan pigment is a pigment exhibiting blue or cyan color. I. Disazo pigments such as C.I. Pigment Blue 25 (dianisidine blue, etc.); I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15: 6, C.I. I. Phthalocyanine pigments such as C.I. Pigment Blue 16 (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 (such as Biclothia Pure Blue BO Lake); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkaline blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).

The green pigment is a pigment exhibiting a green color. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. Pigment green 8, C.I. I. And azo metal complex pigments such as CI Pigment Green 10.
The orange pigment is a pigment exhibiting an orange color. I. Pigment Orange 66 (Isoindoline Orange) and the like, C.I. I. Anthraquinone pigments such as C.I. Pigment Orange 51 (dichloropyrantron orange); I. Pigment orange 2, C.I. I. Pigment orange 3, C.I. I. Pigment Orange 5 and the like Β-naphthol pigments, C.I. I. Pigment orange 4, C.I. I. Pigment orange 22, C.I. I. Pigment orange 24, C.I. I. Pigment orange 38, C.I. I. Naphthol AS pigments such as CI Pigment Orange 74; I. Pigment Orange 61 and other isoindolinone pigments, C.I. I. Perinone pigments such as CI Pigment Orange 43; I. Pigment orange 15, C.I. I. Disazo pigments such as CI Pigment Orange 16; I. Pigment orange 48, C.I. I. Quinacridone pigments such as CI Pigment Orange 49; I. Pigment orange 36, C.I. I. Pigment orange 62, C.I. I. Pigment orange 60, C.I. I. Pigment orange 64, C.I. I. An acetolone pigment such as C.I. Pigment Orange 72; I. Pigment orange 13, C.I. I. And pyrazolone pigments such as CI Pigment Orange 34.
The brown pigment is a pigment exhibiting a brown color. I. Pigment brown 25, C.I. I. And naphthron pigments such as CI Pigment Brown 32.
The violet pigment is a pigment exhibiting a purple color. I. Naphtholone pigments such as CI Pigment Violet 32, C.I. I. Perylene pigments such as CI Pigment Violet 29, C.I. I. Pigment violet 13, C.I. I. Pigment violet 17, C.I. I. Naphthol AS pigments such as CI Pigment Violet 50, C.I. I. Pigment violet 23, C.I. I. And dioxazine pigments such as CI Pigment Violet 37.

The black pigment is a pigment exhibiting black color, such as carbon black, titanium black, C.I. I. Indazine pigments such as CI Pigment Black 1 (aniline black); I. Pigment black 31, C.I. I. And perylene pigments such as CI Pigment Black 32.
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), And strontium titanate (SrTiO ₃ , so-called titanium strontium white). The inorganic particles used for the white pigment may be a simple substance or, for example, oxides such as silicon, aluminum, zirconium and titanium, organometallic compounds, and composite particles with organic compounds.
Among these, the titanium oxide has a lower specific gravity than other white pigments, a large refractive index, and is chemically and physically stable. Since it is excellent in durability against other environments, it is preferably used. In addition to the titanium oxide, another white pigment (may be other than the above-described white pigment) may be used in combination.

For the dispersion of the pigment, for example, a dispersion apparatus such as a ball mill, sand mill, attritor, roll mill, jet mill, homogenizer, paint shaker, kneader, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, etc. Can be preferably used.
In the present invention, it is particularly preferable to add the component C when dispersing the pigment.
In addition, when dispersing the pigment, a synergist corresponding to various pigments may be added as a dispersion aid, if necessary. The content of the dispersion aid in the ink composition is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

The dispersion medium used when the pigment is dispersed in the ink composition is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the polymerizable compound having a low molecular weight may be selected from the dispersion medium. Or a solvent may be used as the dispersion medium. However, the ink composition of the present invention is a radiation curable ink, and is preferably solvent-free without containing the solvent in order to cure the ink after it is applied on the recording medium. This is because when the solvent remains in the cured ink image, the solvent resistance is deteriorated or the VOC (Volatile) of the remaining solvent is reduced.
This is because a problem of “Organic Compound” occurs. For this reason, it is preferable to use the polymerizable compound as the dispersion medium, and to select a polymerizable compound having the lowest viscosity among them in terms of dispersion suitability and handling property of the ink composition.

There is no restriction | limiting in particular as an average particle diameter of the said pigment, Although it can select suitably according to the objective, Since it is excellent in coloring property, so that it is fine, about 0.01-0.4 micrometer is preferable, and 0.02- 0.2 μm is more preferable. The maximum particle size of the pigment is preferably 3 μm, more preferably 1 μm. The pigment particle size can be adjusted by selecting the pigment, dispersant, dispersion medium, dispersion conditions, filtration conditions, etc., and controlling the pigment particle size prevents clogging of the head nozzle. In addition, ink storage stability, ink transparency and curing sensitivity can be maintained. In the present invention, since the component C having excellent dispersibility and stability is contained, even when the fine pigment is used, a uniform and stable ink composition can be obtained.
The particle diameter of the pigment in the ink composition can be measured by a known measurement method. Specifically, it can be measured by a centrifugal sedimentation light transmission method, an X-ray transmission method, a laser diffraction / scattering method, and a dynamic light scattering method.
As content in the said ink composition of the said pigment, when the said pigment is an organic pigment, 1-20 mass% is preferable in conversion of solid content, and 2-10 mass% is more preferable. Moreover, when the said pigment is an inorganic pigment, 1-30 mass% is preferable in conversion of solid content, and 2-25 mass% is more preferable.

<Other ingredients>
The ink composition of the present invention can contain the component C, the polymerizable compound, the pigment, and other components appropriately selected according to the purpose.
Examples of the other components include polymerization initiators, sensitizing dyes, co-sensitizers, resins, surfactants, ultraviolet absorbers, antioxidants, anti-fading agents, ejection stabilizers, adhesion improvers, and leveling. Examples thereof include additives and matting agents. These may be used individually by 1 type and may use 2 or more types together.

-Polymerization initiator-
The ink composition of the present invention preferably contains a polymerization initiator.
The polymerization initiator is preferably a radical polymerization or cationic polymerization initiator, and a photopolymerization initiator is particularly preferable.

The photopolymerization initiator is a compound that generates a chemical change through the action of light or interaction with the electronically excited state of a sensitizing dye to generate at least one of radicals, acids, and bases. .
Examples of the photopolymerization initiator include actinic rays to be irradiated, for example, 400 to 200 nm ultraviolet rays, far ultraviolet rays, g rays, h rays, i rays, KrF excimer laser rays, ArF excimer laser rays, electron rays, X rays, Those having sensitivity to a molecular beam, an ion beam and the like can be appropriately selected and used.
Specific examples of the photopolymerization initiator include Bruce M. et al. Monroe et al., Chemical Review, 93, 435 (1993). R. S. By Davidson, Journal of Photochemistry and biologic A: Chemistry, 73.81 (1993). J. P. Faussier “Photoinitiated Polymerization—Theory and Applications”: Rapra Review vol. 9, Report, Rapra Technology (1998). M. Tsunooka et al. , Prog. Polym. Sci. , 21, 1 (1996). Compounds described in the above, chemical amplification type photoresists described in “Organic Materials for Imaging” edited by Organic Electronics Materials Research Group (see pages 187 to 192) (1993), and compounds used for photocationic polymerization, Etc. Further, F.I. D. Saeva, Topics in Current Chemistry, 156, 59 (1990). G. G. Maslak, Topics in Current Chemistry, 168, 1 (1993). H., et al. B. Shuster et al, JACS, 112, 6329 (1990). , I. D. F. Eaton et al, JACS, 102, 3298 (1980). And the like, which are described in the above and the like, which undergo oxidative or reductive bond cleavage through interaction with the electronically excited state of the sensitizing dye.

  Among these photopolymerization initiators, (a) aromatic ketone compounds, (b) aromatic onium salt compounds, (c) organic peroxides, (d) hexaarylbiimidazole compounds, (e) ketoxime ester compounds , (F) borate compounds, (g) azinium compounds, (h) metallocene compounds, (i) active ester compounds, (j) compounds having a carbon-halogen bond, and the like.

  Examples of the (a) aromatic ketone compound include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” J. Pat. P. FOUASSIER J.M. F. A compound having a benzophenone skeleton or a thioxanthone skeleton described in p77 to 117 of RABEK (1993), an α-thiobenzophenone compound described in Japanese Patent Publication No. 47-6416, a benzoin ether compound described in Japanese Patent Publication No. 47-3981, and Japanese Patent Publication No. 47-22326 Α-substituted benzoin compounds, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, dialkoxybenzophenones described in JP-B-60-26483, JP-B-60- 26403, benzoin ethers described in JP-A-62-181345, JP-B-1-34242, US Pat. No. 4,318,791, α-aminobenzophenones described in European Patent 0284561A1, 2-2114 P-di (dimethylaminobenzoyl) benzene described in JP-A No. 2; thio-substituted aromatic ketones described in JP-A-61-194062; acylphosphine sulfides described in JP-B-2-9597; Examples thereof include acylphosphine described in Japanese Patent Publication No. 63-61950, thioxanthones described in Japanese Patent Publication No. 63-61950, and coumarins described in Japanese Patent Publication No. 59-42864.

  Examples of the (b) aromatic onium salt compound include, for example, elements of groups V, VI and VII of the periodic table, specifically N, P, As, Sb, Bi, O, S, Se, Te, Or aromatic onium salts of I, and the like. Specific examples thereof are described in European Patent No. 104143, US Pat. No. 4,837,124, JP-A-2-150848, and JP-A-2-96514. Iodonium salts, European Patent Nos. 370693, 233567, 297443, 297442, 279210, and 422570, U.S. Patents 3902144, 4933377, 4760013, 4734444, and Sulfonium salts and diazonium salts described in each specification of U.S. Pat. No. 2,833,827 Zonium, etc.), diazonium salt resins (formaldehyde resin of diazodiphenylamine, etc.), N-alkoxypyridinium salts, etc. (for example, U.S. Pat. No. 4,743,528, JP-A 63-138345, JP-A 63- 142345, JP-A-63-142346, JP-B-46-42363, etc., specifically 1-methoxy-4-phenylpyridinium tetrafluoroborate etc.), JP-B-52- The compounds described in JP-A Nos. 147277, 52-14278 and 52-14279 are preferable. These compounds generate radicals and acids as active species.

  Examples of the organic peroxide (c) include organic compounds having one or more oxygen-oxygen bonds in the molecule. Specifically, 3,3′4,4′-tetra- (t- Butylperoxycarbonyl) benzophenone, 3,3'4,4'-tetra- (t-amylperoxycarbonyl) benzophenone, 3,3'4,4'-tetra- (t-hexylperoxycarbonyl) benzophenone, 3, , 3'4,4'-tetra- (t-octylperoxycarbonyl) benzophenone, 3,3'4,4'-tetra- (cumylperoxycarbonyl) benzophenone, 3,3'4,4'-tetra- Preferred examples include (p-isopropylcumylperoxycarbonyl) benzophenone and peroxide compounds such as di-t-butyldiperoxyisophthalate. .

  Examples of the (d) hexaarylbiimidazole compound include lophine dimers described in JP-B-45-37377 and JP-B-44-86516, specifically 2,2′-bis (o- Chlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2 ' -Bis (o, p-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m -Methoxyphenyl) biimidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) 4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis ( (o-trifluorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, etc. are preferred.

  Examples of the (e) ketoxime ester compound include 3-benzoyloxyiminobutan-2-one, 3-acetoxyiminobutan-2-one, 3-propionyloxyiminobutan-2-one, and 2-acetoxyimino. Pentan-3-one, 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3-p-toluenesulfonyloxyiminobutan-2-one, 2-ethoxycarbonyloxyimino-1-phenylpropan-1-one, and the like.

Examples of the (f) borate compound include compounds described in U.S. Pat. Nos. 3,567,453 and 4,343,891, European Patents 109,772 and 109,773, and the like.
Examples of the (g) azinium compound include JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, and JP-B-46-42363. And compounds having the N—O bond described.
Examples of the (h) metallocene compound are described in JP 59-152396, JP 61-151197, JP 63-41484, JP 2-249, and JP 2-4705. And the iron-arene complexes described in JP-A-1-304453, JP-A-1-152109, and the like.
Specific examples of the titanocene compound include di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, and di-cyclopentadienyl-Ti-bis-2,3. 4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti- Bis-2,4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4 -Difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti- -2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyridin-1-yl) phenyl) titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (methylsulfonamido) phenyl] titanium, bis (cyclopenta And dienyl) bis [2,6-difluoro-3- (N-butylbialoyl-amino) phenyl] titanium.

  Examples of the (i) active ester compound include the specifications of European Patent Nos. 0290750, 046083, 156153, 271851, and 0388343, and the specifications of US Pat. Nos. 3,901,710 and 4,181,531. Nitrobenzol ester compounds described in JP-A-60-198538 and JP-A-53-133022, European Patent Nos. 0199672, 84515, 199672, 0441115, and 0101122 , U.S. Pat. Nos. 4,618,564, 4,371,605, and 4,431,774, and JP-A 64-18143, JP-A-2-245756, and JP-A-4-365048. Compound, Shoko 62-2223, Shoko 63 Compounds described in JP 14 340 No. and JP 59-174831, and the like.

  Examples of the compound (j) having a carbon-halogen bond include Wakabayashi et al., Bull. Chem. Soc. Japan, 42, 2924 (1969), a compound described in British Patent 1388492, a compound described in JP-A-53-133428, a compound described in German Patent 3337024, F . C. J. Schaefer et al. Org. Chem. 29, 1527 (1964), a compound described in JP-A-62-258241, a compound described in JP-A-5-281728, a compound described in German Patent 2641100, a German patent 3333450 , Compounds described in German Patent No. 3021590, compounds described in German Patent No. 3021599, and the like.

Preferred specific examples of the compounds (a) to (j) are as follows.

The said polymerization initiator may be used individually by 1 type, and may use 2 or more types together.
As content in the said ink composition of the said polymerization initiator, 0.1-20 mass% is preferable in conversion of the total solid of this ink composition, 0.5-10 mass% is more preferable, 1-7 Mass% is particularly preferred.

-Sensitizing dye-
When the ink composition of the present invention contains the photopolymerization initiator, it is preferable to contain a sensitizing dye for the purpose of improving the sensitivity of the photopolymerization initiator.
Preferred examples of the sensitizing dye include those that absorb light having a wavelength of 350 to 450 nm.
Examples of the sensitizing dye include polynuclear aromatics (for example, pyrene, perylene, triphenylene), xanthenes (for example, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (for example, thiacarbocyanine). Oxacarbocyanine), merocyanines (eg, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, Anthraquinone), squaliums (for example, squalium), coumarins (for example, 7-diethylamino-4-methylcoumarin), and the like.
Preferable specific examples of the sensitizing dye include compounds represented by the following general formulas (IX) to (XIII).

In the general formula (IX), A ¹ represents a sulfur atom or NR ⁵⁰ . R ⁵⁰ represents an alkyl group or an aryl group. L ² represents a nonmetallic atomic group that forms a basic nucleus of a dye together with adjacent A ² and adjacent carbon atoms. R ⁵¹ and R ⁵² each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and these may combine with each other to form an acidic nucleus of the dye. W represents an oxygen atom or a sulfur atom.
In the general formula (X), Ar ¹ and Ar ² each independently represent an aryl group, and are linked via a bond with —L ³ —. L ³ represents —O— or S—. W has the same meaning as that shown in the general formula (IX).
In the general formula (XI), A ² represents a sulfur atom or NR ⁵⁹ , and L ⁴ represents a nonmetallic atomic group that forms a basic nucleus of the dye together with adjacent A ² and a carbon atom. R ⁵³ , R ⁵⁴ , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ and R ⁵⁸ each independently represent a monovalent nonmetallic atomic group. R ⁵⁹ represents an alkyl group or an aryl group.
In the general formula (XII), A ³ and A ⁴ each independently represent —S— or NR ⁶² — or NR ⁶³ —. R ⁶² and R ⁶³ each independently represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. L ⁵ and L ⁶ each independently represent a nonmetallic atomic group that forms a basic nucleus of a dye together with adjacent A ³ , A ⁴ and adjacent carbon atoms. R ⁶⁰ and R ⁶¹ are each independently a hydrogen atom or a monovalent nonmetallic atomic group, or may be bonded to each other to form an aliphatic or aromatic ring.
In the general formula (XIII), R ⁶⁶ represents an aromatic ring or a hetero ring which may have a substituent. A ⁵ represents an oxygen atom, a sulfur atom or NR ⁶⁷ —. R ⁶⁴ , R ⁶⁵ and R ⁶⁷ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group. R ⁶⁷ and R ⁶⁴ , and R ⁶⁵ and R ⁶⁷ may be bonded to each other to form an aliphatic or aromatic ring.

Specific preferred examples of the compounds represented by the general formulas (IX) to (XIII) include the following exemplified compounds A-1 to A-20.

-Co-sensitizer-
The ink composition of the present invention may contain a co-sensitizer for the purpose of further improving sensitivity or suppressing polymerization inhibition by oxygen.
Examples of the co-sensitizer include amines (for example, M. R. Sander et al., “Journal of Polymer Society”, Vol. 10, page 3173 (1972), Japanese Examined Patent Publication No. 44-20189, Japanese Patent Laid-Open No. 51- 82102, JP 52-134692, JP 59-138205, JP 60-84305, JP 62-18537, JP 64-33104, Research And compounds described in Disclosure No. 33825). Specific examples of the amines include triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline, and the like.
Examples of the co-sensitizer include thiols and sulfides (for example, thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142277, A disulfide compound disclosed in JP-A-56-75643 is also preferable. Specific examples of the thiols and sulfides include 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercaptonaphthalene, and the like.
Examples of the co-sensitizer include amino acid compounds (for example, N-phenylglycine), organometallic compounds described in JP-B-48-42965 (for example, tributyltin acetate), and JP-B-55. No. 34414, a hydrogen donor described in JP-A-6-308727, a sulfur compound described in JP-A-6-308727 (for example, trithiane), a phosphorus compound described in JP-A-6-250387 (diethylphosphite, etc.), Examples thereof include Si—H and Ge—H compounds described in Japanese Patent Application No. 6-191605.

-Resin-
The ink composition of the present invention may contain a resin for the purpose of adjusting film physical properties of the recorded image.
Examples of the resin include acrylic polymer, polyvinyl butyral resin, polyurethane resin, polyamide resin, polyester resin, epoxy resin, phenol resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl formal resin, shellac, vinyl resin, and acrylic resin. Examples thereof include resins, rubber resins, waxes, and other natural resins. These may be used individually by 1 type and may use 2 or more types together. In the present invention, known waxes may be used in place of the resin.

-Surfactant-
The ink composition of the present invention may contain a surfactant for the purpose of adjusting the liquid properties of the ink composition.
Examples of the surfactant include nonionic surfactants, cationic surfactants, anionic surfactants, betaine surfactants, and organic fluoro compounds.

-UV absorber-
The ink composition of the present invention preferably contains an ultraviolet absorber from the viewpoint of improving the weather resistance of recorded images and preventing discoloration, and also from the viewpoint of improving the stability of the ink composition. From the viewpoint of preventing fading of recorded images, it is preferable to contain an antifading agent (for example, various organic and metal complex compounds), and inkjet In the case of recording, from the viewpoint of ejection stability, it is preferable to contain an ejection stabilizer (for example, conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride). From the viewpoint of improving the adhesion to the recording medium, it may contain an adhesion improver (for example, a very small amount of organic solvent or a tackifier that does not inhibit the polymerization) If necessary, a leveling additive, may contain such matting agent.

<Physical properties>
-Viscosity-
The viscosity of the ink composition of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. However, in consideration of discharge properties, the discharge temperature is preferably 30 mPa · s or less, and 20 mPa · s. The following is more preferable.
When the viscosity exceeds 30 mPa · s, the ejection stability may be inferior.
Further, the viscosity of the ink composition of the present invention at room temperature (25 ° C.) is preferably 200 mPa · s or less, and more preferably 100 mPa · s or less.
By setting the viscosity at the room temperature (25 ° C.) high, even when a porous recording medium is used, ink penetration into the recording medium can be prevented, and uncured monomers can be reduced and odors can be reduced. Furthermore, it is advantageous in that dot bleeding at the time of ink droplet landing can be suppressed, and as a result, high image quality can be obtained. On the other hand, when the viscosity at room temperature (25 ° C.) exceeds 200 mPa · s, there may be a problem in delivery of the ink composition.
The viscosity can be measured using, for example, a conical plate type rotational viscometer (E type viscometer).

-Surface tension-
There is no restriction | limiting in particular as surface tension of the ink composition of this invention, Although it can select suitably according to the objective, For example, 20-30 mN / m is preferable and 23-28 mN / m is more preferable. When the ink composition is recorded on various recording media such as polyolefin, PET, coated paper, uncoated paper, etc., it is preferably 20 mN / m or more in terms of bleeding and penetration, and 30 mN / m in terms of wettability. The following is preferred.
The surface tension can be measured using, for example, a Wilhelmy method surface tension meter or a Du Nouy surface tension meter.

-Manufacturing-
There is no restriction | limiting in particular as a manufacturing method of the ink composition of this invention, According to the objective, it can select suitably, For example, it can manufacture by mixing each above-mentioned component. In addition, the said mixing can be performed according to a well-known method using a well-known mixer etc.

−Use−
The ink composition of the present invention can be suitably used as an ink for various image recordings, and can be particularly suitably used as an ink composition for inkjet recording. In this case, the ink composition is printed on a recording medium by an ink jet printer, and then the printed ink composition (recorded image) is irradiated with the actinic radiation to be cured and image recording is performed. .
The image recorded matter (printed matter) obtained using the ink composition of the present invention is excellent in the strength of the image portion because the image portion is cured by irradiation with the active radiation such as ultraviolet rays. For this reason, besides image recording (image formation), it can be suitably used for various applications such as formation of an ink receiving layer (image part) of a lithographic printing plate.

-Inkjet recording-
Here, ink jet recording using the ink composition of the present invention will be described.
The ink jet recording method and conditions are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the ink composition of the present invention is heated to 40 to 80 ° C. After adjusting the viscosity of the ink to 30 mPa · s or less, it is preferable to discharge from the ink nozzle head because it is excellent in discharge stability. Generally, a radiation curable ink composition such as the ink composition of the present invention generally has a higher viscosity than a general water-based ink, and therefore has a large viscosity fluctuation range due to temperature fluctuation during image recording (printing). The viscosity variation of the ink composition has a great influence on the droplet size and the droplet ejection speed as it is, which causes image quality deterioration. For this reason, it is necessary to keep the temperature of the ink composition during image recording (printing) as constant as possible. The temperature control range of the ink composition is preferably set temperature ± 5 ° C, more preferably set temperature ± 2 ° C, and particularly preferably set temperature ± 1 ° C.

  There is no restriction | limiting in particular as an inkjet recording device used for the said inkjet recording, Although it can select suitably from well-known things and can use a commercial item suitably, For example, the temperature of the said ink composition is sufficient. It is preferable to provide the stabilization means. In this case, it is preferable that the part where the ink composition is kept at a constant temperature is the entire piping system and members from the ink tank (intermediate tank if there is an intermediate tank) to the nozzle ejection surface.

  The method for controlling the temperature of the ink composition is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors in each piping region and perform heating control according to the flow rate of the ink composition and the environmental temperature. The ink nozzle head for discharging the ink composition is preferably heated. In this case, the ink jet recording apparatus main body is thermally blocked or insulated so as not to be affected by the temperature from the outside air. Is more preferable. In order to shorten the startup time of the ink jet recording apparatus (printer) 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.

-Ink composition ejection conditions-
In the image recording method of the present invention, it is preferable that the ink composition of the present invention is heated to a constant temperature and the time from the ejection of the ink composition to the irradiation of the active radiation is shortened.
The time from the ejection of the ink composition to the irradiation of the active radiation (hereinafter sometimes referred to as “pre-irradiation time”) is preferably 0.01 to 0.5 seconds, for example, 0.01 to 0 3 seconds is more preferable, and 0.01 to 0.15 seconds is particularly preferable.
By controlling the pre-irradiation time within the above range, it is possible to effectively prevent the ejected ink composition from bleeding before being cured, and also to a porous recording medium. The actinic radiation can be irradiated before the ink composition penetrates deeper than the light source reaches, the residual unreacted monomer can be suppressed, and as a result, odor can be reduced. It is advantageous.

By using the ink composition of the present invention and discharging the ink composition under the above-described ink composition discharge conditions, etc., the ink is discharged in droplets on various recording media having different surface wettability. The dot diameter of the composition can be kept constant, which is advantageous in that high image quality can be obtained. In addition, in order to obtain a color image, it is preferable to superimpose in order from the ink of the color with low lightness (the ink composition of the present invention). When ink with low brightness (the ink composition of the present invention) is overlaid, the actinic radiation hardly reaches the lower ink, resulting in inhibition of curing sensitivity, increase in residual monomer, generation of odor, deterioration of adhesion, etc. May be easier. In addition, the irradiation with the actinic radiation may be performed in a lump after discharging all the inks (the ink composition of the present invention), but from the viewpoint of promoting curing, it is performed for each color. Preferably it is done.
According to the above, although the ink composition of the present invention is repeatedly heated and lowered, even when stored under such temperature conditions due to the action or function of the C component. This is advantageous in that the dispersibility reduction of the pigment is effectively suppressed, excellent color developability is obtained over a long period of time, and the decrease in ejection stability due to aggregation of the pigment is also effectively suppressed. .

-Curing-
The ink composition of the present invention is cured by irradiation with actinic radiation after image recording is performed, but the irradiation condition of the actinic radiation in this case is not particularly limited and is appropriately selected according to the purpose. be able to.
The irradiation method of the active radiation is described in, for example, Japanese Patent Application Laid-Open No. 60-132767. Specifically, a light source is provided on both sides of the head unit, and the head and the light source are scanned by a shuttle system. The irradiation with the actinic radiation is performed after a certain period of time after ink landing. Further, the curing is completed by another light source that is not driven. In addition, WO99 / 54415 discloses a method using an optical fiber or a method of irradiating a recording unit with UV light by applying a collimated light source to a mirror surface provided on the side of the head unit as the method of irradiating the active radiation. Has been. In the present invention, these irradiation methods can be employed.

-Recording medium-
The recording medium on which an image is recorded by discharging the ink composition of the present invention is not particularly limited and can be appropriately selected according to the purpose. Papers such as ordinary uncoated paper and coated paper Examples thereof include various non-absorbable resin materials used for so-called soft packaging, or resin films obtained by molding the non-absorbent resin materials. As the resin film, for example, PET film, OPS film, OPP film, ONy film, PVC film, PE film, TAC film, polycarbonate film, acrylic film, ABS film, polyacetal film, PVA film, rubber film, Etc. Further, metals, glasses and the like can be used as the recording medium.

-Recorded image-
What is obtained by curing the ink composition of the present invention is the image recording material of the present invention, and as the image recording material, the ink composition of the present invention is ejected onto the recording medium, A cured product is preferred. At this time, it is more preferable that the ejection is performed by ink jet recording using an ink jet printer.
In the image recorded matter (printed matter) of the present invention, the ink composition used for image recording is the ink composition of the present invention, and contains fine pigment particles uniformly and stably dispersed. It has excellent sharpness, high image quality, excellent weather resistance, and can be suitably used in a wide range of fields.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
<Synthesis of the C component>
-Synthesis of the monomer (M-1)-
62.6 g of 2-amino-4-hydroxy-6-methylpyrimidine was mixed with 2200 mL of pyridine, and a few drops of nitrobenzene were added and stirred. To this, 93.1 g of 2-methacryloyloxyethyl isocyanate was added and stirred at 90 ° C. for 10 hours. The reaction solution was cooled to room temperature, and 2.5 L of acetone was added and filtered. The obtained white solid was dried under reduced pressure to synthesize 120 g of the monomer (M-1).
The identification data of 1H-NMR (300 MHz, CDCl ₃ , δ) of the monomer (M-1) are 12.97 (s, 1H), 11.95 (s, 1H), 10.50 (s, 1H), 6.18 (s, 1H), 5.78 (s, 1H), 5.54 (s, 1H), 4.27 (t, 2H), 3.59 (t, 2H), 2. 23 (s, 3H), 1.93 (s, 3H). Met.

-Synthesis of the monomer (M-2 to M-6)-
J. et al. Am. Chem. Soc. , 120, 6761-6769 (1998), and the monomer (M-4, M-6) was synthesized by the same method as the monomer (M-1).
M-4: 1H-NMR (300 MHz, CDCl ₃ , δ)
13.02 (s, 1H), 11.75 (s, 1H), 9.62 (s, 1H), 6.16 (s, 1H), 5.76 (s, 1H), 5.54 (s , 1H), 4.27 (t, 2H), 3.59 (t, 2H), 2.45 (t, 2H), 1.93 (s, 3H), 1.62 (m, 2H), 1 .50-1.20 (m, 20H), 0.90 (t, 3H).
M-6: 1H-NMR (300 MHz, CDCl ₃ , δ)
12.98 (d, 1H), 11.95 (s, 1H), 10.47 (s, 1H), 6.45 (s, 1H), 6.14 (m, 1H), 5.80 (m , 2H), 4.30 (t, 2H), 3.59 (t, 2H), 2.23 (s, 3H).

-Synthesis of the monomer (M-11)-
25.0 g of 2-amino-4-hydroxy-6-methylpyrimidine was mixed with 230 g of hexamethylene diisocyanate and stirred at 100 ° C. for 16 hours. Hexane was added to the reaction solution, and the precipitated white solid was filtered (intermediate A). DMSO400mL and 2-hydroxyethyl methacrylate 26.0g were mixed here, several drops of dibutyltin dilaurate was added, and it heated and stirred at 60 degreeC for 24 hours. The reaction solution was poured into water for crystallization, and dried under reduced pressure to synthesize 80 g of the monomer (M-11).
The identification data of 1H-NMR (300 MHz, CDCl ₃ , δ) of the monomer (M-11) are 13.18 (s, 1H), 11.92 (s, 1H), 10.08 (s, 1H), 6.17 (s, 1H), 5.84 (s, 1H), 5.60 (s, 1H), 4.51 (s, 1H), 4.37 (m, 4H), 3. 20 (m, 4H), 2.25 (s, 3H), 1.95 (s, 3H), 1.70 (m, 2H), 1.60 (m, 2H), 1.51 (m, 2H) ), 1.38 (m, 2H). Met.

-Synthesis of the monomer (M-7)-
Using the intermediate A obtained by the synthesis of the monomer (M-11), 26.0 g of 2-hydroxyethyl methacrylate in the synthesis of the monomer (M-11) was converted to vinylbenzyl alcohol (m, p mixture) 26. The monomer (M-7) was synthesized in the same manner as the synthesis of the monomer (M-11) except that the amount was changed to 0.8 g.
-Synthesis of the monomer (M-17)-
Monomer (M-17) was synthesized in the same manner as the synthesis of monomer (M-11) except that hexamethylene diisocyanate in the synthesis of monomer (M-11) was changed to trimethylhexamethylene diisocyanate.

—Synthesis of Graft Copolymer 1 <Graft Copolymer Exemplified as 1): Monomer Represented by M-1 / Terminal Methacryloylated Polymethyl Methacrylate Copolymer—
Three-necked flask in which 2.0 g of the synthesized monomer (M-1), 18.0 g of polymethyl methacrylate having a methacryloyl group at the end (AA-6: manufactured by Toagosei Co., Ltd.), and 20 g of N-methylpyrrolidone were substituted with nitrogen. The mixture was stirred with a stirrer (Shinto Kagaku Co., Ltd .: Three One Motor), heated to 78 ° C. while flowing nitrogen into the flask. 27 mg of 2,2-azobis (2,4-dimethylvaleronitrile) (V-65 manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto, and the mixture was heated and stirred at 78 ° C. for 2 hours. After 2 hours, 27 mg of V-65 was further added, and the mixture was stirred with heating for 3 hours. The obtained reaction solution was poured into 1500 mL of methanol / water with stirring, and the resulting precipitate was dried by heating, whereby the graft copolymer 1 <represented by the above 1) was represented by M-1 Monomer / terminal methacryloylated polymethyl methacrylate copolymer> was synthesized.

—Synthesis of Graft Copolymer 2 <Graft Copolymer Illustrated as 6) above: Monomer / Polyethylene Glycol Mono (meth) acrylate Copolymer Represented by M-11>
In the synthesis example of the graft copolymer 1, the graft copolymer 2 is the same as the synthesis example of the graft copolymer 1 except that the monomer (M-1) is changed to the monomer (M-11). <The graft copolymer illustrated as said 6): The monomer represented by M-11 / polyethylene glycol mono (meth) acrylate copolymer> was synthesize | combined.

-Graft copolymer 3 <Graft copolymer exemplified as the above 12): monomer represented by M-1 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethylmethacrylate copolymer> Synthesis of
4.0 g of the monomer (M-1), 2.0 g of 3- (N, N-dimethylaminopropylacrylamide), polymethyl methacrylate having a methacryloyl group at the terminal (AA-6: manufactured by Toagosei Co., Ltd.) 14.0 g And 20 g of N-methylpyrrolidone are introduced into a nitrogen-substituted three-necked flask, stirred with a stirrer (Shinto Kagaku Co., Ltd .: Three-One Motor), heated while flowing nitrogen into the flask, and heated to 78 ° C. did. 27 mg of 2,2-azobis (2,4-dimethylvaleronitrile) (V-65 manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto, and the mixture was heated and stirred at 78 ° C. for 2 hours. After 2 hours, 27 mg of V-65 was further added, and the mixture was heated and stirred for 3 hours. The obtained reaction solution was poured into 1500 mL of methanol / water with stirring, and the resulting precipitate was heated and dried, whereby the graft copolymer represented as graft copolymer 3 <12) was represented by M-1. Monomer / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethyl methacrylate copolymer> was synthesized.

-Graft copolymer 4 <Graft copolymer exemplified as 13): Monomer represented by M-1 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polybutylacrylate copolymer> Synthesis of
In the synthesis example of the graft copolymer 3, the graft copolymer was changed except that the polymethyl methacrylate having a methacryloyl group at the terminal was changed to polybutyl acrylate having a methacryloyl group at the terminal (AB-6: manufactured by Toagosei Co., Ltd.). In the same manner as in the synthesis example of the polymer 3, the graft copolymer exemplified as the graft copolymer 4 <13): monomer represented by M-1 / 3- (N, N-dimethylamino) propylacrylamide / Terminal methacryloylated polybutyl acrylate copolymer> was synthesized.

-Graft copolymer 5 <Graft copolymer exemplified as 15): Monomer represented by M-11 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethylmethacrylate copolymer> Synthesis of
In the synthesis example of the graft copolymer 3, the graft copolymer is the same as the synthesis example of the graft copolymer 3 except that the monomer (M-1) is changed to the monomer (M-11). 5 <Graft copolymer exemplified as 15): Monomer represented by M-11 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethylmethacrylate copolymer> was synthesized.

-Graft copolymer 6 <Graft copolymer exemplified as 17): Monomer represented by M-17 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethylmethacrylate copolymer> Synthesis of
In the synthesis example of the graft copolymer 3, the graft copolymer is the same as the synthesis example of the graft copolymer 3 except that the monomer (M-1) is changed to the monomer (M-17). 6 <Graft copolymer exemplified as 17): Monomer represented by M-17 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethyl methacrylate copolymer> was synthesized.

—Synthesis of Graft Copolymer 7 <Graft Copolymer Exemplified as 20): Monomer Represented by M-7 / 2-Vinylpyridine / Polyethylene Glycol Mono (meth) acrylate Copolymer> —
In the synthesis example of the graft copolymer 3, the graft (M-1) was changed to the graft (M-7), and 3- (N, N-dimethylaminopropylacrylamide) was changed to 2-vinylpyridine. Except for the above, in the same manner as in the synthesis example of graft copolymer 3, graft copolymer illustrated as graft copolymer 7 <20) above: monomer represented by M-9 / 2-vinylpyridine / polyethylene glycol mono (Meth) acrylate copolymer> was synthesized.

-Graft copolymer 8 <Synthesis of graft copolymer exemplified as 29): monomer represented by M-1 / monomer represented by N-1 / polyethylene glycol mono (meth) acrylate copolymer>
In the synthesis example of the graft copolymer 3, in the same manner as the synthesis example of the graft copolymer 3 except that 3- (N, N-dimethylaminopropylacrylamide) was changed to the monomer (N-1). Graft copolymer 8 <Graft copolymer exemplified as 29): monomer represented by M-1 / monomer represented by N-1 / polyethylene glycol mono (meth) acrylate copolymer> was synthesized. .

-Graft copolymer 9 <Graft copolymer exemplified as 32): monomer represented by M-1 / monomer represented by N-1 / 3- (N, N-dimethylamino) propylacrylamide / terminal Synthesis of methacryloylated polymethyl methacrylate copolymer>
2.0 g of the monomer (M-1), 2.0 g of the monomer (N-1), 2.0 g of 3- (N, N-dimethylaminopropylacrylamide), polymethyl methacrylate having a methacryloyl group at the terminal ( AA-6: Toa Gosei Co., Ltd. (14.0 g) and N-methylpyrrolidone (20 g) were introduced into a nitrogen-substituted three-necked flask and stirred with a stirrer (Shinto Kagaku Co., Ltd .: Three-One Motor). The mixture was heated up to 78 ° C. while flowing in. 27 mg of 2,2-azobis (2,4-dimethylvaleronitrile) (V-65 manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto, and the mixture was heated and stirred at 78 ° C. for 2 hours. After 2 hours, 27 mg of V-65 was further added, and the mixture was stirred with heating for 3 hours. The obtained reaction solution was poured into 1500 mL of methanol / water with stirring, and the resulting precipitate was dried by heating, whereby the graft copolymer represented as graft copolymer 9 <32 above): represented by M-1. Monomer / monomer represented by N-1 / 3- (N, N-dimethylamino) propylacrylamide / terminated methacryloylated polymethyl methacrylate copolymer> was synthesized.

-Graft copolymer 10 <Graft copolymer exemplified as 33): monomer represented by M-1 / monomer represented by N-2 / 3- (N, N-dimethylamino) propylacrylamide / terminal Synthesis of methacryloylated polymethyl methacrylate copolymer>
In the synthesis example of the graft copolymer 9, the graft copolymer is the same as the synthesis example of the graft copolymer 9 except that the monomer (N-1) is changed to the monomer (N-2). 10 <Graft copolymer exemplified as 33): monomer represented by M-1 / monomer represented by N-2 / 3- (N, N-dimethylamino) propylacrylamide / terminal methacryloylated polymethyl methacrylate Copolymer> was synthesized.

Example 1
The synthesized graft copolymer 1 <graft copolymer exemplified as the above 1): monomer represented by M-1 / terminal methacryloylated polymethylmethacrylate copolymer> is synthesized with the following polymerizable compounds (i) and ( ii) Dissolved in <component (A)>, put together with the following pigment <component (B)> in a motor mill M50 (manufactured by Eiger), using zirconia beads having a diameter of 0.65 mm, a peripheral speed of 9 m / The mixture was dispersed for 6 hours to obtain a stock solution of the active energy ray-curable ink composition. Next, the following polymerization initiator was added to the stock solution of the ink composition, mixed gently, and then filtered under pressure with a membrane filter to obtain the active energy ray-curable inkjet ink of Example 1 (invention of the present invention). Ink composition) was produced. The content of each component in the ink composition of Example 1 is as follows.
Graft copolymer 1 ... 1.5g
Polymerizable compound:
(I) propoxylated neopentylglycol diacrylate (NPGPODA: manufactured by Sartomer Co., Ltd.) ... 60.0 g
(Ii) Captolactone-modified dipentaerythritol hexaacrylate (DPCA-60: manufactured by Nippon Kayaku Co., Ltd.) 27.5 g
Quinacridone pigment (PV-19: manufactured by Clariant Japan Co., Ltd.) ... 5g
Polymerization initiator (acylphosphine oxide compound (Lucirin TPO-L: manufactured by BASF Japan Ltd.)) ... 5.0 g

(Examples 2 to 10)
Example 1 is the same as Example 1 except that the graft copolymer 1 is changed to the synthesized graft copolymer 2, 3, 4, 5, 6, 7, 8, 9, 10 respectively. Thus, active energy ray-curable inkjet inks (ink compositions of the present invention) of Examples 2, 3, 4, 5, 6, 7, 8, 9, and 10 were produced.

(Comparative Example 1)
The active energy ray curing of Comparative Example 1 was performed in the same manner as in Example 1 except that the graft copolymer 1 was changed to a commercially available pigment dispersant (SOLPERSE 24000GR, manufactured by Nihon Librizol Co., Ltd.). A type inkjet ink was obtained.

(Comparative Example 2)
In Example 1, the active energy ray curing of Comparative Example 2 was performed in the same manner as in Example 1 except that the graft copolymer 1 was changed to a commercially available pigment dispersant (SOLPERSE 32000, manufactured by Nihon Librizol Corporation). A type inkjet ink was obtained.

(Examples 11-13 and Comparative Examples 3-4)
In Examples 3, 4, and 9 and Comparative Examples 1 and 2, Examples 3, 4, and 9 were used except that the quinacridone pigment (PV-19) was changed to PY-128 (manufactured by Clariant Japan Co., Ltd.). In the same manner as in Comparative Examples 1 and 2, inkjet ink compositions of Examples 11, 12, 13 and Comparative Examples 3 and 4 were produced.

(Example 20)
The synthesized polymer C-3 was dissolved in the following polymerizable compounds (i) and (ii) <the component (A)>, and together with the following pigment <the component (B)>, a motor mill M50 (manufactured by Eiger). ) And using zirconia beads having a diameter of 0.65 mm, dispersion was performed at a peripheral speed of 5 m / s for 3 hours to obtain a stock solution of the active energy ray-curable ink composition. Next, the following polymerization initiator was added to the stock solution of the ink composition, mixed gently, and then filtered under pressure with a membrane filter to obtain the active energy ray-curable inkjet ink of Example 1 (invention of the present invention). Ink composition) was produced. The content of each component in the ink composition of Example 1 is as follows.
Polymer C-3 ... 1.5g
Polymerizable compound:
(I) propoxylated neopentyl glycol diacrylate (NPPGODA: manufactured by Sartomer Co., Ltd.) 29.5 g
(Ii) Dipropylene glycol diacrylate (DPGDA: manufactured by Daicel Cytec Co., Ltd.) 40.0 g
(Iii) Phenoxyethyl acrylate (AMP-10G: manufactured by Shin-Nakamura Chemical Co., Ltd.) 20.0 g
Acetron pigment (PY-120 manufactured by Clariant Japan Co., Ltd.) .. 4.0g
Polymerization initiator (acylphosphine oxide compound (Lucirin TPO-L: manufactured by BASF Japan Ltd.)) ... 5.0 g

(Examples 21 to 22)
In Example 1, the active energy ray-curable types of Examples 48 to 49 were the same as Example 20 except that the polymer C-3 was changed to the synthesized polymers C-4 and C-9, respectively. An inkjet ink (ink composition of the present invention) was produced.

(Comparative Examples 9 and 10)
In Example 20, except that the polymer C-3 was changed to a commercially available pigment dispersant (SOLPERSE24000GR, manufactured by Nihon Librizol Corporation) and a commercially available pigment dispersant (SORPERSE 32000, Nihon Lubrizol Corporation), respectively. In the same manner as in Example 20, active energy ray-curable inkjet inks of Comparative Examples 9 and 10 were obtained.

(Examples 14-16 and Comparative Examples 5-6)
In Examples 3, 4, 9, and Comparative Examples 1 and 2, except that the polymerizable compound and the polymerization initiator were changed to the following, in the same manner as in Examples 3, 4, 9, and Comparative Examples 1 and 2, The inkjet inks of Examples 14, 15, and 16 and Comparative Examples 5 and 6 were produced.
Polymerizable compound (i) Oxetane compound (OXT-221: manufactured by Toa Gosei Co., Ltd.) ... 70.0 g
(Ii) Epoxy compound (Celoxide 3000: manufactured by Daicel Chemical Industries, Ltd.)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 17.5g
Polymerization initiator (triphenylsulfonium salt (UVI-6992, manufactured by Dow Chemical Co., Ltd.) ... 5.0g

(Examples 17 to 19 and Comparative Examples 7 to 8)
In Examples 14, 15, and 16 and Comparative Examples 5 and 6, Examples 14, 15, and 16, except that quinacridone pigment PV-19 was changed to phthalocyanine pigment PB15: 3 (manufactured by Clariant Japan Co., Ltd.). In the same manner as in Comparative Examples 5 and 6, inkjet inks of Examples 17, 18, and 19 and Comparative Examples 7 and 8 were produced.

-Evaluation of ink composition-
Each of the obtained ink compositions was evaluated according to the following method. The results are shown in Table 1.
<Viscosity>
The viscosity at 40 ° C. of each ink composition was measured using an E-type viscometer. The viscosity was evaluated according to the following criteria.
A: Less than 30 mPas B: 30 mPas or more and less than 100 mPas

<Stability>
After each ink composition was stored at 25 ° C. for 1 month and stored at 70 ° C. for 24 hours, the dispersion state was evaluated by visual observation and change in viscosity. Evaluation was made according to the following criteria.
◎: Precipitation does not occur and viscosity does not increase ○: Precipitation does not occur and viscosity increases slightly, but there is no problem with ejection performance △: Precipitation does not occur, but ejection performance decreases due to increase in viscosity And practically problematic level ×: occurrence of precipitates is observed

<Average particle size>
About each ink composition, the volume reference | standard average particle diameter D50 was measured using the light-scattering diffraction type particle size distribution measuring apparatus (LA910, the Horiba, Ltd. make), and evaluated according to the following references | standards.
A: D50 is less than 100 nm B: D50 is 100 nm or more and less than 200 nm C: D50 is 200 nm or more

<Curing property>
Each ink composition obtained was recorded (printed) on art paper using an inkjet printer (printing density 300 dpi, droplet ejection frequency 4 kHz, nozzle number 64), and then a Deep UV lamp (made by Ushio, SP-7) was used. The recorded image was irradiated with ultraviolet rays as active radiation under the condition that the recorded image had an energy of 100 mJ / cm ² to obtain a recorded image.
The obtained recorded image was touched with a finger, and the presence or absence of stickiness was evaluated according to the following criteria.
A: No stickiness B: Slight stickiness C: Extremely sticky

From Table 1, the ink composition of the present invention can be suitably recorded by inkjet recording (suitable for the image recording method of the present invention), and is cured with high sensitivity to irradiation with active radiation (ultraviolet rays). In addition, it is possible to record a high-quality image without stickiness (the recorded image of the present invention), and even under long-term storage conditions, the viscosity of the pigment does not increase and the pigment dispersibility does not occur. The dispersion stability was found to be good.
On the other hand, in the case of a comparative ink using a commercially available polymer dispersant, the initial pigment dispersibility is good, but in particular, the storage stability (stability (60 ° C.)) under high temperature conditions is inferior and practical. It was a level that would be a problem.
In the above examples, each synthesized graft polymer is composed of an interaction site with the pigment and a graft chain (macromonomer), and the graft chain (macromonomer) is more dispersed than the pigment. It was considered that it functions or functions as a steric repulsive group that exhibits affinity to the medium and sterically prevents particles from aggregating in the dispersion. In the present invention, since the graft polymer described above has the same configuration as the graft copolymer used in the above examples, the same action or function as the graft copolymer used in each of the above examples. It is assumed that he plays.

The ink composition of the present invention can be used for normal printing to record a sharp image with excellent color developability and obtain a high-quality image recorded matter (printed matter), as well as a resist, a color filter, and an optical disc. It can also be suitably used in the production of a laser and is also useful as an optical modeling material. In addition, since the ink composition of the present invention can be directly formed on a non-absorbable recording medium based on digital data by applying to the ink jet recording method, the ink composition of the present invention can perform image recording on a large area. It is also suitably used for production of printed matter (printed matter).
Since the image recording method of the present invention uses the ink composition of the present invention, the image recording method of the present invention is suitably used for printing applications that are required to record images with high image quality and excellent durability.
Since the image recorded matter of the present invention can be obtained by using the ink composition of the present invention, the image recorded matter is excellent in durability with high image quality, and thus is widely used in various applications.

Claims (10)

An ink composition comprising at least a polymerizable compound, a pigment, and a polymer containing a repeating unit derived from a monomer represented by the following general formula (1).

In the general formula (1), R ¹ represents a hydrogen atom or an alkyl group. R ² and R ³ represent a monovalent substituent. R ² and R ³ may be linked to form a cyclic structure. W represents any of —CO—, —C (═O) O—, —CONR—, —OC (═O) —, and a phenylene group. R represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group. X represents a single bond or a divalent linking group. The general formula (1), wherein R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ represent an alkyl group, an aryl group, or a heterocyclic group which may have a substituent. Ink composition.   3. The ink composition according to claim 1, wherein the polymer is a graft copolymer further comprising a polymerizable oligomer (macromonomer) having an ethylenically unsaturated double bond at a terminal as a copolymer unit.   The ink composition according to any one of claims 1 to 4, comprising a polymerization initiator.   The ink composition according to claim 5, wherein the polymerizable compound is a radical polymerizable compound, and the polymerization initiator is a photo radical generator.   The ink composition according to claim 5, wherein the polymerizable compound is a cationic polymerizable compound and the polymerization initiator is a photoacid generator.   The ink composition according to claim 1, which is an ink jet composition.   A printing step of printing the ink composition according to claim 1 on a recording medium, and a curing step of curing the ink composition by irradiating the printed ink composition with actinic radiation. An image recording method.   An image recording material obtained by curing the ink composition according to claim 1.   The printed matter according to claim 10, wherein the ink composition is printed on the recording medium by an ink jet printer, and then the active ink is irradiated to cure the ink composition.