JP5171218B2 - Ink composition, image recording method using the ink composition, and printed matter using the ink composition - Google Patents

Description

  The present invention has a good dispersibility of the colorant, excellent color developability, can be cured by irradiation with actinic radiation, and can form a high-quality image. The present invention relates to an image recording method using an ink composition and a printed matter using the ink composition.

  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 that can be cured by irradiation with actinic radiation. According to this method, a sharp image can be formed by irradiating actinic 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. In general, in order to impart a clear color tone and high coloring power to an ink composition, it is essential to make the pigment particles finer. In particular, in an ink composition for ink jet recording, the ejected ink droplets are the Since the sharpness is greatly affected, it is essential to use pigment particles that have a small amount of ejected droplets and that are finer than the thickness of the ink cured film formed by the ink composition. As described above, when the pigment particles are further refined in order to obtain a high coloring power, it becomes difficult to disperse the pigment particles and pigment aggregates are easily generated. Further, when a pigment dispersant is added, there arises a problem that the viscosity of the ink composition increases. 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. The ink composition used in the ink jet method is contained in a cartridge, heated during ejection, and cooled during non-ejection and storage. Therefore, the ink composition undergoes repeated heating-cooling temperature changes. There is a problem that the pigment dispersibility is adversely affected, the dispersibility of the pigment is lowered with time, and the generation of pigment aggregates and the increase in viscosity of the ink composition are likely to occur.

Therefore, there has been a demand for an ink composition that has sufficient fluidity and stably disperses a finely divided pigment, and that is excellent in the temporal stability of pigment dispersion. Various proposals have been made on dispersants for obtaining the above.
In order to improve the affinity with the pigment, an ink composition using a pigment derivative as a dispersant (see, for example, Patent Documents 1 and 2), a specific group such as phthalocyanine, quinacridone, and the like as a dispersant. Containing a specific monomer that dissolves the dispersant and a dispersant such as an ink composition using a polymer having a polymer (see, for example, Patent Document 3) and a poly (ethyleneimine) -poly (12-hydroxystearic acid) graft polymer Ink compositions that do not use organic solvents have been proposed (see, for example, Patent Document 4).
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

  An object of the present invention is to solve the conventional 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 to provide an ink composition suitable for use, an image recording method using the ink composition, and a printed material using the ink composition.

As a result of intensive studies, the present inventors have found that when a specific polymer is used as a pigment dispersant, it is excellent in pigment dispersibility, and it is effective to reduce dispersion stability even after long-term storage and repeated temperature changes. The present invention was completed by finding that an ink composition with a reduced viscosity was obtained.
Means for solving the problems are as follows. That is,
<1> An ink composition comprising at least a polymerizable compound, a pigment, and a polymer represented by the following general formula (1).
In the general formula (1), R ¹ and R ² represent a monovalent substituent. R ³ represents an (m + n) -valent organic linking group, R ⁴ represents a single bond or an (a + 1) -valent organic linking group, and R ⁵ represents either a single bond or a divalent organic linking group. Represent. a represents 1 to 10, m represents 1 to 8, n represents 2 to 9, and m + n is 3 to 10. P represents a polymer backbone. The m Ps may be the same or different.
<2> A polymer skeleton represented by P is a vinyl monomer polymer, a vinyl monomer copolymer, an ester polymer, an ether polymer, a urethane polymer, an amide polymer, an epoxy polymer, a silicone polymer, and The ink composition according to <1>, wherein the ink composition is derived from at least one selected from the group consisting of any one of these modified products and copolymers.
<3> The ink composition according to any one of <1> to <2>, including a polymerization initiator.
<4> The ink composition according to <3>, wherein the polymerizable compound is a radical polymerizable compound, and the polymerization initiator is a photo radical generator.
<5> The ink composition according to <3>, wherein the polymerizable compound is a cationic polymerizable compound, and the polymerization initiator is a photoacid generator.
<6> The ink composition according to any one of <1> to <5>, which is an inkjet composition.
<7> A discharge step of discharging the ink composition according to any one of <1> to <6> onto a recording medium, and a curing step of curing the discharged ink composition by irradiation with actinic radiation. And an image recording method.
<8> A printed material obtained by curing the ink composition according to any one of <1> to <6>.
<9> The printed material according to <8>, wherein the ink composition is ejected onto a recording medium by an ink jet printer, and then the ejected ink composition is cured by irradiation with active radiation.

  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. An ink composition suitable for ink jet recording applications, an image recording method using the ink composition, and a printed material using the ink composition Can do.

(Ink composition, image recording method, and printed matter)
The ink composition of the present invention comprises (A) a polymerizable compound, (B) a pigment, and (C) a polymer represented by the general formula (1) (hereinafter referred to as “polymer of the general formula (1)”). And 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 preferred, and ultraviolet rays are more preferred from the viewpoints of curing sensitivity and device availability.

The image recording method of the present invention further includes a discharge step of discharging the ink composition of the present invention onto a recording medium, and a curing step of curing the discharged ink composition by irradiation with actinic radiation. Other processes appropriately selected depending on the situation are included. The printed material of the present invention is obtained by curing the ink composition of the present invention.
The contents of the ink composition of the present invention are described below, and the contents of the image recording method and printed matter of the present invention are also described below.

<(C) Polymer of general formula (1)>
The polymer (C) of the general formula (1) (hereinafter sometimes simply referred to as “C component”) is a polymer represented by the following general formula (1). In the present invention, the component C acts or functions as a pigment dispersant, has a high affinity with the (B) pigment, and has a good adsorptivity to the (B) pigment and an affinity for the medium. The ink composition of the present invention containing the component C is excellent in dispersion stability because it has a segment responsible for steric repulsion between the pigments (B).

  The polymer represented by the following general formula (1) has a structure represented by the following general formula at the end of the polymer, so it has excellent adsorptivity to a solid surface, excellent micelle forming ability, excellent surface activity, and various It has various functions and functions and is suitable as a pigment dispersant.

-R ¹ and R ^2-
In the general formula (1), R ¹ and R ² 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, An arylsulfonyl group, a sulfamoyl group, a sulfonylamino group, and a heterocyclic group are preferable. 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, A heterocyclic group is more preferable, and a hydrogen atom, an alkyl group, an aryl group, and a heterocyclic group are particularly preferable.
R ¹ and R ² 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.

Examples of ^R 1, the number of carbon atoms of the alkyl group represented by ^{R 2,} preferably from 1 to 30, 1 to 20 is 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 An ethyl group, a (4-chlorophenyl) methyl group, and a (2,4-dichlorophenyl) methyl group are preferable, and an ethyl group, a butyl group, a hexyl group, a benzyl group, an N, N-diethylcarbamoylmethyl group, and an N, N-dibutylcarbamoyl group Methyl group, 1- (N, N-dibutylcarbamoyl) ethyl group, 1-methyl-2-phenoxyethyl group, (4- Rorofeniru) methyl group, (2,4-dichlorophenyl) methyl group is more preferable.

Examples of ^R 1, the number of carbon atoms of the aryl group represented by ^{R 2,} 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 Among them, among them, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-chlorophenyl group, 2-methoxyphenyl group, 3-ethoxyphenyl group, 4-butoxyphenyl Groups are more preferred.

Preferred examples of the halogen atom represented by R ¹ and R ² 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.
Examples of ^R 1, carbon atoms in the alkoxy group represented by ^{R 2,} preferably from 1 to 30, 1 to 20 is more preferable. Examples of the alkoxy group include methoxy, ethoxy, propoxy, butoxy, hexyloxy, 2-ethylhexyloxy, 3,5,5-trimethylhexyloxy, octyloxy, decyloxy, 2- Preferred are phenoxyethoxy group, 2- (3,5-di-t-butylphenoxy) ethoxy group, dibutylcarbamoylmethoxy group, hexadecyloxy group, octadecyloxy group, etc. 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 more preferable.

Examples of ^R 1, the number of carbon atoms of the aryl group represented by ^{R 2,} 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 -A nitrophenyloxy group etc. are more preferable.

Examples of ^R 1, the number of carbon atoms of the alkylthio group represented by ^{R 2,} preferably from 1 to 30, 1 to 20 is 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, 2- (3,5-di-t-butylphenoxy) ethylthio group, dibutylcarbamoylmethylthio group, hexadecylthio group, octadecylthio group and the like are preferable. Among these, methylthio group, ethylthio group, butylthio group, hexylthio group, 2- An ethylhexylthio group, a 3,5,5-trimethylhexylthio group, a 2-phenoxyethylthio group, and a dibutylcarbamoylmethylthio group are more preferable.

As carbon number of the arylthio group represented by said R < ¹ >, R < ² >, 6-30 are preferable and 6-20 are more preferable. Examples of the arylthio group include phenylthio group, tolylthio group, 4-chlorophenylthio group, 4-acetamidophenylthio group, 2-butoxyphenylthio group, 2-benzoylaminophenylthio group, 2,5-dimethoxy-4- Nitrophenylthio group, 3-octyloxyphenylthio group and the like are preferable, and among these, phenylthio group, tolylthio group, 4-chlorophenylthio group, 4-acetamidophenylthio group, 2-butoxyphenylthio group, 2,5- A dimethoxy-4-nitrophenylthio group is more preferred.

Examples of ^R 1, the carbon number of the alkoxycarbonyl group represented by ^{R 2,} preferably from 1 to 30, 1 to 20 is 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 Among these, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, hexyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, among these, , 5,5-trimethyl hexyloxy group, 2-phenoxyethoxy group, and more preferably dibutylcarbamoyl methoxycarbonyl group.

Examples of ^R 1, the number of carbon atoms of the acylamino group represented by ^{R 2,} preferably from 1 to 30, 1 to 20 is 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 A '-dichlorobenzoylamino group, 2', 4'-di-t-amylbenzoylamino group, acetylmethylamino group, benzoylmethylamino group, acetylbenzylamino group, etc. are preferable, and among them, acetylamino group, butyrylamino group Benzoylamino group, toluoylamino group, phenoxyacetyl group, 2 ′, 4′-di-t-amylbenzoylamino group, acetylmethylamino group, benzoylmethylamino group, and acetylbenzylamino group are more preferable.

Examples of ^R 1, the number of carbon atoms of the carbamoyl group represented by ^{R 2,} preferably from 1 to 30, 1 to 20 is more preferable. Examples of the carbamoyl group include a carbamoyl group, N-phenylcarbamoyl group, N-butylcarbamoyl group, N-octylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-diethylcarbamoyl group, N, N-dibuty 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 Group, piperidinocarbonyl group, N, N-bis (2-methoxyethyl) carbamoyl group and the like are preferable. Among these, N-butylcarbamoyl group, N-octylcarbamoyl group, N-phenylcarbamoyl group, N, N -Diethylcarbamoyl group, N, N-dibu Carbamoyl group, N- methyl -N- phenylcarbamoyl group is more preferable.

Examples of ^R 1, the number of carbon atoms of the alkylsulfonyl group represented by ^{R 2,} preferably from 1 to 30, 1 to 20 is more preferable. As the alkylsulfonyl group, for example, a methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl group, a hexylsulfonyl group, a benzylsulfonyl group, and the like are preferable. Among these, a methylsulfonyl group and a benzylsulfonyl group are more preferable.

Examples of ^R 1, the number of carbon atoms of the aryl sulfonyl group represented by ^{R 2,} preferably from 1 to 30, 1 to 20 is more preferable. As the arylsulfonyl group, for example, a phenylsulfonyl group, a 4-methylphenylsulfonyl group, a naphthylsulfonyl group, a 4-methoxysulfonyl group, a 4-chlorophenylsulfonyl group, and the like are preferable, and among them, a methylsulfonyl group, a phenylsulfonyl group 4-methylphenylsulfonyl group is more preferable.

As carbon number of the sulfamoyl group represented by said R < ¹ >, R < ² >, 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 A sulfamoyl group, a morpholinosulfonyl group, a piperidinosulfonyl group, an N, N-bis (2-methoxyethyl) sulfonyl group, and the like are preferable. Among these, a sulfamoyl group, an N-phenylsulfamoyl group, N, N -Dibutylsulfamoyl group, N, N-diphenylsulfamoyl group, N-methyl-N-phenylsulfamoyl group More preferable.

The heterocyclic group represented by R ¹ and R ² 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. Is preferred.

-R ⁴ -
R ⁴ represents a single bond or an (a + 1) -valent organic linking group. a represents an integer of 1 to 10, preferably 1 to 7, more preferably 1 to 5, and particularly preferably 1 to 3. The (a + 1) -valent organic linking group is composed of 1 to 100 carbon atoms, 10 or less nitrogen atoms, 50 or less oxygen atoms, 1 to 200 hydrogen atoms, and 20 or less sulfur atoms. A group is preferred, and among the (a + 1) -valent organic linking groups, from 1 to 10 carbon atoms, 5 or less nitrogen atoms, 10 or less oxygen atoms, 1 to 30 hydrogen atoms, and 5 or less sulfur atoms More preferred are organic linking groups.

  Specific examples of the (a + 1) -valent organic linking group include a group composed of the following structural units or a combination thereof (which may form a ring structure).

  The (a + 1) -valent organic linking group may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms (methyl group, ethyl group, etc.), and 6 to 16 carbon atoms. Aryl group (phenyl group, naphthyl group etc.), hydroxyl group, amino group, carboxyl group (acetoxy group etc.), sulfonamide group, N-sulfonylamide group, C1-C6 acyloxy group, C1-C6 Alkoxy group (methoxy group, ethoxy group, etc.), halogen atom (chlorine, bromine, etc.), C2-C7 alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, cyclohexyloxycarbonyl group, etc.), cyano group, carbonate ester Group (t-butyl carbonate and the like), and the like.

-R ^5-
In the general formula (1), R ⁵ represents either a single bond or a divalent organic linking group. The n R ^{5 s} may be the same or different.
The divalent organic linking group is preferably a group composed of 1 to 100 carbon atoms, 10 or less nitrogen atoms, 50 or less oxygen atoms, 1 to 200 hydrogen atoms, and 20 or less sulfur atoms. And may be substituted with a substituent. Further, the divalent organic linking group includes a group composed of 1 to 50 carbon atoms, 8 or less nitrogen atoms, 25 or less oxygen atoms, 1 to 100 hydrogen atoms, and 10 or less sulfur atoms. Preferably, a divalent organic linking group composed of 1 to 30 carbon atoms, 6 or less nitrogen atoms, 15 or less oxygen atoms, 1 to 50 hydrogen atoms, and 7 or less sulfur atoms is more preferable. A divalent organic linking group composed of 10 carbon atoms, 5 or less nitrogen atoms, 10 or less oxygen atoms, 1 to 30 hydrogen atoms, and 5 or less sulfur atoms is particularly preferable.
Specific examples of the divalent organic linking group include groups composed of the following structural units or combinations thereof.

  When the divalent organic linking group has a substituent, examples of the substituent include an alkyl group having 1 to 20 carbon atoms (methyl group, ethyl group, etc.), an aryl group having 6 to 16 carbon atoms (phenyl group). , Naphthyl group, etc.), hydroxyl group, amino group, carboxyl group (acetoxy group, etc.), sulfonamide group, N-sulfonylamide group, acyloxy group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms (methoxy group, Ethoxy group etc.), halogen atom (chlorine, bromine etc.), C2-C7 alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, cyclohexyloxycarbonyl group etc.), cyano group, carbonate group (t-butyl carbonate) Etc.).

-R ^3-
In the general formula (1), R ³ represents an (m + n) -valent organic linking group. m + n is 3-10.
Examples of the (m + n) -valent organic linking group represented by R ³ include 1 to 100 carbon atoms, 10 or less nitrogen atoms, 50 or less oxygen atoms, 1 to 200 hydrogen atoms, and 20 or less sulfur. A group composed of atoms is included and may be substituted with a substituent.

  Specific examples of the (m + n) -valent organic linking group include groups composed of the following structural units or combinations thereof (which may form a ring structure).

  Examples of the (m + n) -valent organic linking group include groups composed of 1 to 60 carbon atoms, 10 or less nitrogen atoms, 40 or less oxygen atoms, 1 to 120 hydrogen atoms, and 10 or less sulfur atoms. Preferably, a group composed of 1 to 50 carbon atoms, 10 or less nitrogen atoms, 30 or less oxygen atoms, 1 to 100 hydrogen atoms, and 7 or less sulfur atoms is more preferable, and 1 to 40 carbon atoms, A group composed of 8 or less nitrogen atoms, 20 or less oxygen atoms, 1 to 80 hydrogen atoms, and 5 or less sulfur atoms is particularly preferred.

  When the (m + n) -valent organic linking group has a substituent, examples of the substituent include an alkyl group having 1 to 20 carbon atoms (methyl group, ethyl group, etc.), an aryl group having 6 to 16 carbon atoms ( Phenyl group, naphthyl group, etc.), hydroxyl group, amino group, carboxyl group (acetoxy group, etc.), sulfonamide group, N-sulfonylamide group, C1-C6 acyloxy group, C1-C6 alkoxy group (methoxy) Group, ethoxy group, etc.), halogen atom (chlorine, bromine, etc.), C2-C7 alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, cyclohexyloxycarbonyl group etc.), cyano group, carbonate group (t- Butyl carbonate, etc.).

Here, specific examples [(1) to (17)] of the (m + n) -valent organic linking group represented by R ³ are shown below. However, the present invention is not limited to these.

  Among the specific examples ((1) to (17)), the following (m + n) -valent organic linking group is particularly preferable from the viewpoint of availability of raw materials, ease of synthesis, and solubility in various solvents.

-M and n-
In the said General formula (1), m represents 1-8, 1-5 are preferable, 1-4 are more preferable, and 1-3 are especially preferable.
Moreover, n represents 2-9, 2-8 are preferable, 2-7 are more preferable, and 3-6 are especially preferable.

-P-
In the general formula (1), P represents a polymer skeleton and can be selected from known polymers according to the purpose. The m Ps may be the same or different.
Among the above polymers, a vinyl monomer polymer, a vinyl monomer copolymer, an ester polymer, an ether polymer, a urethane polymer, an amide polymer, an epoxy polymer, and a silicone polymer are used to form a polymer skeleton. And modified products and copolymers thereof [eg, polyether / polyurethane copolymer, copolymer of polyether / vinyl monomer, etc. (random copolymer, block copolymer, graft copolymer, etc. Any of these may be included. At least one selected from the group consisting of any of the following: vinyl monomer polymer, vinyl monomer copolymer, ester-based polymer, ether-based polymer, urethane-based polymer, and their modified products and copolymer More preferred is at least one selected from the group consisting of any one of the coalesced polymers, and particularly preferred are vinyl monomer polymers and vinyl monomer copolymers.
The polymer is preferably soluble in an organic solvent. When the polymer has a low affinity with the organic solvent, for example, when used as a pigment dispersant, the affinity with the dispersion medium is weakened, and it may be impossible to secure an adsorption layer sufficient for stabilizing the dispersion.

  Examples of the vinyl monomer include (meth) acrylic acid esters, crotonic acid esters, vinyl esters, maleic acid diesters, fumaric acid diesters, itaconic acid diesters, (meth) acrylamides, styrenes, and vinyl ethers. , Vinyl ketones, olefins, maleimides, (meth) acrylonitrile, vinyl monomers having an acidic group, and the like.

  Examples of the (meth) acrylate esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n- (meth) acrylate. Butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, amyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate , 2-ethylhexyl (meth) acrylate, t-octyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, acetoxyethyl (meth) acrylate, phenyl (meth) acrylate, (meth ) 2-hydroxyethyl acrylate, (meth) acrylic acid-2-hydroxypropiate , (Meth) acrylic acid-3-hydroxypropyl, (meth) acrylic acid-4-hydroxybutyl, (meth) acrylic acid 2-methoxyethyl, (meth) acrylic acid 2-ethoxyethyl, (meth) acrylic acid 2- (2-methoxyethoxy) ethyl, (meth) acrylic acid 3-phenoxy-2-hydroxypropyl, (meth) acrylic acid-2-chloroethyl, (meth) acrylic acid glycidyl, (meth) acrylic acid-3,4-epoxy Cyclohexylmethyl, vinyl (meth) acrylate, (meth) acrylic acid-2-phenylvinyl, (meth) acrylic acid-1-propenyl, allyl (meth) acrylate, (meth) acrylic acid-2-allyloxyethyl, (Meth) acrylic acid propargyl, (meth) acrylic acid benzyl, (meth) acrylic acid diethylene glycol (Meth) acrylic acid diethylene glycol monoethyl ether, (meth) acrylic acid triethylene glycol monomethyl ether, (meth) acrylic acid triethylene glycol monoethyl ether, (meth) acrylic acid polyethylene glycol monomethyl ether, (meta ) Polyethylene glycol monoethyl ether acrylate, β-phenoxyethoxyethyl (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, Trifluoroethyl (meth) acrylate, octafluoropentyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, dicyclopenta (meth) acrylate Alkenyl, (meth) acrylic acid tribromophenyl, (meth) tribromophenyl oxyethyl acrylate, (meth) acrylic acid -γ- butyrolactone, and the like (meth) acrylate and phenoxyethyl.

  Examples of the crotonic acid esters include butyl crotonate and hexyl crotonate.

  Examples of the vinyl esters include vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, and vinyl benzoate.

  Examples of the maleic acid diesters include dimethyl maleate, diethyl maleate, and dibutyl maleate.

  Examples of the fumaric acid diesters include dimethyl fumarate, diethyl fumarate, and dibutyl fumarate.

  Examples of the itaconic acid diesters include dimethyl itaconate, diethyl itaconate, and dibutyl itaconate.

  Examples of the (meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- n-butylacryl (meth) amide, Nt-butyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-phenyl (meth) acrylamide, N-nitrophenyl acrylamide, N-ethyl-N-phenyl acrylamide, N-benzyl (meth) acrylamide, (meth) acryloylmorpholine, diacetone acrylamide , - methylol acrylamide, N- hydroxyethyl acrylamide, vinyl (meth) acrylamide, N, N- diallyl (meth) acrylamide, N- allyl (meth) acrylamide, and the like.

  Examples of the styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, butyl styrene, hydroxy styrene, methoxy styrene, butoxy styrene, acetoxy styrene, chlorostyrene, dichlorostyrene, bromostyrene, chloro Examples thereof include methylstyrene, hydroxystyrene protected with a group that can be deprotected by an acidic substance (for example, t-Boc), methyl vinylbenzoate, α-methylstyrene, and the like.

  Examples of the vinyl ethers include methyl vinyl ether, ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, methoxyethyl vinyl ether, and phenyl vinyl ether.

  Examples of the vinyl ketones include methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.

  Examples of the olefins include ethylene, propylene, isobutylene, butadiene, and isoprene.

  Examples of the maleimides include maleimide, butyl maleimide, cyclohexyl maleimide, and phenyl maleimide.

  Examples of the vinyl monomer include those described above, (meth) acrylonitrile, heterocyclic groups substituted with a vinyl group (for example, vinylpyridine, N-vinylpyrrolidone, vinylcarbazole, etc.), N-vinylformamide, N- Vinylacetamide, N-vinylimidazole, vinylcaprolactone, and the like can also be used. Further, for example, vinyl monomers having a functional group such as a urethane group, a urea group, a sulfonamide group, a phenol group, and an imide group can also be used. As such a monomer having a urethane group or a urea group, for example, an appropriate synthesis is performed using an addition reaction between an isocyanate group and a hydroxyl group, or an addition reaction between an isocyanate group and an amino group. Is possible. Specifically, an addition reaction between an isocyanate group-containing monomer and a compound containing one hydroxyl group, an addition reaction between an isocyanate group-containing monomer and a compound containing one primary or secondary amino group, a hydroxyl group-containing monomer It can be appropriately synthesized by an addition reaction between a monoisocyanate and a monoisocyanate, or an addition reaction between a primary or secondary amino group-containing monomer and a monoisocyanate.

  Examples of the vinyl monomer having an acidic group include a vinyl monomer having a carboxyl group, a vinyl monomer having a sulfonic acid group, a vinyl monomer having a phosphoric acid group, a vinyl monomer having a phenolic hydroxyl group, and a sulfonamide group. Vinyl monomers to be used.

  Examples of the vinyl monomer having a carboxyl group include (meth) acrylic acid, vinyl benzoic acid, maleic acid, maleic acid monoalkyl ester, fumaric acid, itaconic acid, crotonic acid, cinnamic acid, acrylic acid dimer, and the like. It is done. Further, addition reaction product of a monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and a cyclic anhydride such as maleic anhydride, phthalic anhydride, or cyclohexanedicarboxylic anhydride, ω-carboxy-polycaprolactone Mono (meth) acrylates can also be used. Moreover, you may use anhydride containing monomers, such as maleic anhydride, itaconic anhydride, and citraconic anhydride, as a precursor of a carboxyl group. Of these, (meth) acrylic acid is particularly preferable from the viewpoints of copolymerizability, cost, solubility, and the like.

  Examples of the vinyl monomer having a sulfonic acid group include 2-acrylamido-2-methylpropanesulfonic acid.

  Examples of the vinyl monomer having a phosphoric acid group include phosphoric acid mono (2-acryloyloxyethyl ester), phosphoric acid mono (1-methyl-2-acryloyloxyethyl ester), and the like.

The molecular weight of the polymer represented by the general formula (1) is preferably a weight average molecular weight of 3,000 to 100,000, more preferably 5,000 to 80,000, and 7,000 to 60,000. Is particularly preferred.
When the weight average molecular weight is within the above range, the effects of the plurality of adsorption sites introduced at the ends of the polymer are sufficiently exhibited, and the performance is excellent in adsorbability on solid surfaces, micelle formation ability, and surface activity. Demonstrate. In particular, when the polymer compound according to the present invention is used as a pigment dispersant, good dispersibility and dispersion stability can be achieved.

The polymer represented by the general formula (1) is, for example, the following method, that is,
1) A polymer having a functional group selected from a carboxyl group, a hydroxyl group, an amino group and the like introduced at the terminal, an acid halide having a plurality of the adsorption sites, an alkyl halide having a plurality of the adsorption sites, or a plurality of the adsorptions A method of polymerizing an isocyanate having a moiety, etc.,
2) A method of Michael addition reaction of a polymer having a carbon-carbon double bond introduced at the terminal and a mercaptan having a plurality of the adsorption sites,
3) A method of reacting a polymer having a carbon-carbon double bond introduced at the end thereof and the mercaptan having the adsorption site in the presence of a radical generator,
4) A method of reacting a polymer in which a plurality of mercaptans are introduced at a terminal with a compound having a carbon-carbon double bond and the adsorption site in the presence of a radical generator,
5) A method of radical polymerization of a vinyl monomer in the presence of a mercaptan compound having a plurality of the adsorption sites,
Etc. can be synthesized.

Among the above methods, the methods 2), 3), 4), and 5) are preferable in terms of ease of synthesis, and the methods 3), 4), and 5) are more preferable, and the method 5) is preferable. Is particularly preferred.
More specifically, the method 5) is preferably a method in which a vinyl monomer is radically polymerized in the presence of a compound represented by the following general formula (2).

In the general formula ^{(2), R 1, R} 2, R 3, R 4, a, m, and ^{n, R 1, R 2, R} 3 in each of the general formula ^{(1), R 4, a} , It is synonymous with m and n, The preferable aspect is also the same.

The compound represented by the general formula (2) is obtained by the following method, that is,
6) A method of converting a halide compound having a plurality of adsorption sites into a mercaptan compound (a method of reacting with thiourea and hydrolyzing, a method of reacting directly with NaSH, a method of reacting with CH ₃ COSNa and hydrolyzing, etc. Listed),
7) A method in which a compound having 3 to 10 mercapto groups in one molecule and a compound having the adsorption site and having a functional group capable of reacting with a mercapto group are subjected to an addition reaction,
However, the method of 7) is more preferable from the viewpoint of ease of synthesis.

Suitable examples of the functional group capable of reacting with a mercapto group in the method 7) include acid halides, alkyl halides, isocyanates, and carbon-carbon double bonds.
It is particularly preferable that the functional group capable of reacting with the mercapto group is a carbon-carbon double bond, and the addition reaction is a radical addition reaction. The carbon-carbon double bond is more preferably a mono- or di-substituted vinyl group in terms of reactivity with the mercapto group.

  Specific examples of the compound having 3 to 10 mercapto groups in one molecule [(18) to (34)] include the following compounds.

  Among the specific examples of the above compounds ((18) to (34)), the following compounds are particularly preferable in view of availability of raw materials, ease of synthesis, and solubility in various solvents.

  The radical addition reaction product of the compound having 3 to 10 mercapto groups in one molecule and the compound having the pigment adsorption structure and having a carbon-carbon double bond is, for example, in the one molecule. A compound having 3 to 10 mercapto groups and a compound having the above-mentioned pigment adsorption structure and having a carbon-carbon double bond are dissolved in a suitable solvent, and a radical generator is added thereto, and about It can obtain using the method (thiol-ene reaction method) to add at 50 to 100 degreeC.

Examples of a suitable solvent used in the thiol-ene reaction method include a compound having 3 to 10 mercapto groups in one molecule, a compound having the pigment adsorbing structure and a carbon-carbon double bond. , And the solubility of the resulting radical addition reaction product can be selected arbitrarily.
Examples of the solvent include methanol, ethanol, propanol, isopropanol, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methoxypropyl acetate, ethyl lactate, ethyl acetate, Examples include acetonitrile, tetrahydrofuran, dimethylformamide, chloroform, toluene, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the radical generator include 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis- (2,4′-dimethylvaleronitrile), and 2,2′-azobisisobutyric acid. Examples thereof include azo compounds such as dimethyl, peroxides such as benzoyl peroxide, and persulfates such as potassium persulfate and ammonium persulfate.

Used in the method of the 5), the vinyl monomer is not particularly limited, for example, those similar to the vinyl monomers used in obtaining the polymer skeleton represented by P ¹ in the general formula (1) is used It is done.

The vinyl monomer may be polymerized by only one kind, or may be copolymerized by using two or more kinds in combination.
In addition, when applied to a photocurable composition that requires alkali development processing, the polymer compound of the present invention includes a vinyl monomer having one or more acidic groups and a vinyl monomer having no one or more acidic groups. And are more preferably copolymerized.

  The polymer of component C in the present invention is a known method using the vinyl monomer and a compound represented by the general formula (2) (hereinafter sometimes simply referred to as “chain transfer agent”). Can be obtained by polymerization according to a conventional method. For example, these vinyl monomers and the chain transfer agent are dissolved in a suitable solvent, a radical polymerization initiator is added thereto, and polymerized in a solution at about 50 ° C. to 220 ° C. (solution polymerization method). Can be obtained.

  A suitable solvent used in the solution polymerization method can be arbitrarily selected depending on the monomers used and the solubility of the copolymer to be produced. For example, methanol, ethanol, propanol, isopropanol, 1-methoxy- Examples include 2-propanol, 1-methoxy-2-propyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methoxypropyl acetate, ethyl lactate, ethyl acetate, acetonitrile, tetrahydrofuran, dimethylformamide, chloroform, toluene, and the like. These solvent may be used individually by 1 type, and may use 2 or more types together.

  Examples of radical polymerization initiators include 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis- (2,4′-dimethylvaleronitrile), and 2,2′-azobisisobutyric acid. Examples thereof include azo compounds such as dimethyl, peroxides such as benzoyl peroxide, and persulfates such as potassium persulfate and ammonium persulfate.

In the present invention, the component C may be used alone or in combination of two or more.
The content of the component C in the ink composition of the present invention is less than 1% by mass with respect to the amount of the pigment added, resulting in insufficient dispersibility of the pigment particles and a large particle size (aggregation). In some cases, a dispersion may be obtained. If the amount exceeds 100% by mass with respect to the amount of the pigment added, viscosity may increase due to an extra polymer.
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.

Examples of the known dispersants (pigment dispersants) include polymer dispersants [for example, polyamidoamine and its salt, polycarboxylic acid and its salt, high molecular weight unsaturated acid ester, modified polyurethane, modified polyester, modified poly (meta ) Acrylate, (meth) acrylic copolymer, naphthalenesulfonic acid formalin condensate], polyoxyethylene alkyl phosphate ester, polyoxyethylene alkyl amine, alkanolamine, pigment derivative, and the like.
The polymer dispersant can be further classified into a linear polymer, a terminal-modified polymer, a graft polymer, and a block polymer according to its structure.

  The polymer dispersant is adsorbed on the surface of the pigment and acts to prevent reaggregation. Therefore, a terminal-modified polymer, a graft polymer, and a block polymer having an anchor site to the surface of the pigment are preferable structures. On the other hand, the pigment derivative has an effect of promoting adsorption of the polymer dispersant by modifying the surface of the pigment.

  Specific examples of the known dispersant (pigment dispersant) include “Disperbyk-101 (polyamidoamine phosphate), 107 (carboxylic acid ester), 110 (copolymer containing an acid group)”, 130, manufactured by BYK Chemie. (Polyamide), 161, 162, 163, 164, 165, 166, 170 (polymer copolymer) ”,“ BYK-P104, P105 (high molecular weight unsaturated polycarboxylic acid) ”,“ EFKA 4047, 4050, manufactured by EFKA Corporation ” 4010, 4165 (polyurethane-based), EFKA4330, 4340 (block copolymer), 4400, 4402 (modified polyacrylate), 5010 (polyesteramide), 5765 (high molecular weight polycarboxylate), 6220 (fatty acid polyester), 6745 (Phthalocyanine derivative), 6750 ( Zo pigment derivative) ”,“ Ajisper PB821, PB822 ”manufactured by Ajinomoto Fan Techno Co., Ltd.,“ Floren TG-710 (urethane oligomer) ”manufactured by Kyoeisha Chemical Co., Ltd.,“ Polyflow No. 50E, No. 300 (acrylic copolymer) ” “Disparon KS-860, 873SN, 874, # 2150 (aliphatic polycarboxylic acid), # 7004 (polyetherester), DA-703-50, DA-705, DA-725”, Kao, manufactured by Enomoto Kasei Co., Ltd. “Demol RN, N (Naphthalenesulfonic acid formalin polycondensate), MS, C, SN-B (aromatic sulfonic acid formalin polycondensate)”, “Homogenol L-18 (polymer polycarboxylic acid)”, “Emulgen 920, 930, 935, 985 (polyoxyethylene nonylphenyl ether)”, “Aceta Min 86 (stearylamine acetate), Lubrizol "Solsperse 5000 (phthalocyanine derivative), 22000 (azo pigment derivative), 13240 (polyesteramine), 3000, 17000, 27000 (polymer having a functional part at the end) , 24000, 28000, 32000, 38500 (graft type polymer) ”,“ Nikkor T106 (polyoxyethylene sorbitan monooleate), MYS-IEX (polyoxyethylene monostearate) ”manufactured by Nikko Chemical Co., Ltd., and the like.

<(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 photocationic polymerizable monomers and photoradical polymerizable monomers that cause a reaction are preferred.

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 cationic photopolymerizable 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, and JP-A-2001-310938. Preferably, epoxy compounds, vinyl ether compounds, oxetane compounds and the like described in each publication such as JP 2001-310937 A and 2001-220526 Jpn.

  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 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 more 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 more 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 examples thereof include known oxetane compounds described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217. It is done.
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, ethyldiethylene 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-hydroxybutyl ( (Meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate Rate, 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 -Methacryloyloxytyl succinic acid, 2-methacryloyllo Cihexahydrophthalic acid, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, 2-hydroxy-3-phenoxy Propyl (meth) acrylate, EO-modified phenol (meth) acrylate, EO-modified cresol (meth) acrylate, EO-modified nonylphenol (meth) acrylate, PO-modified nonylphenol (meth) acrylate, EO-modified-2-ethylhexyl (meth) acrylate, di Examples thereof include cyclopentenyl (meth) acrylate and dicyclopentanyl (meth) acrylate.

  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 (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, tricyclodecane di (meth) acrylate, dipropylene glycol di (meth) acrylate, neopentyl glycol propylene oxydi An acrylate etc. are mentioned.

Examples of the trifunctional (meth) acrylate include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane alkylene oxide-modified tri (meth) acrylate, pentaerythritol tri (meth) Acrylate, dipentaerythritol tri (meth) acrylate, trimethylolpropane tri ((meth) acryloyloxypropyl) ether, isocyanuric acid alkylene oxide modified tri (meth) acrylate, 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 (meth) acrylamides used as the photoradical polymerizable monomer include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N- n-butyl (meth) acrylamide, Nt-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, and the like.

  Examples of the aromatic vinyl used as the photo radical polymerizable monomer include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro. Styrene, bromostyrene, vinyl benzoic acid methyl ester, 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene , 3-hexylstyrene, 4-hexylstyrene, 3-octylstyrene, 4-octylstyrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allylstyrene, isopropyl Nirusuchiren, butenylstyrene, octenyl styrene, 4-t-butoxycarbonyl styrene, 4-methoxystyrene, 4-t-butoxystyrene, and the like.

  Furthermore, examples of the photo-radical polymerizable monomer in the present invention include vinyl esters [vinyl acetate, vinyl propionate, vinyl versatate, etc.], allyl esters [eg, allyl acetate], 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.], and the like.

  Among these, as the radical photopolymerizable monomer in the present invention, (meth) acrylates and (meth) acrylamides are preferable from the viewpoint of curing speed, and tetrafunctional or higher (meth) acrylates are more preferable, and ink composition In view of the viscosity of the product, it is preferable to use polyfunctional (meth) acrylate, monofunctional or bifunctional (meth) acrylate, and (meth) acrylamide together.

  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) contained in the ink composition of the present invention (hereinafter sometimes simply referred to as “component B” or “pigment”) functions as a coloring material of the ink composition. As a result of the pigment having a fine particle diameter being uniformly and stably dispersed in the ink composition by the function of the component C, the ink composition of the present invention has excellent color development, sharpness and excellent weather resistance. Can be formed.
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. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Examples of the organic pigment and inorganic pigment contained in the ink composition of the present invention include yellow pigment, magenta pigment, blue, cyan pigment, green pigment, orange pigment, brown pigment, violet pigment, black pigment, white pigment, and the like. Can be mentioned.

  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. Non-benzidine azo pigments such as CI Pigment Yellow 180; 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, etc.).

  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 an organic compound. Above all, the titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so that it has a high hiding power and coloring power as a pigment, and further, an acid or alkali. 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 ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and the like Can be preferably used.
In the present invention, it is preferable to add the component C when dispersing the pigment.
In addition, when dispersing the pigment, a synergist according 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 to 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.

The average particle size of the pigment is not particularly limited and may be appropriately selected depending on the intended purpose. However, the smaller the average particle size, the better the color developability, and therefore, about 0.01 to 0.4 μm is preferable. 0.02-0.2 μm is more preferable. The maximum particle size of the pigment is preferably 3 μm, more preferably 1 μm. The particle size of the pigment can be adjusted by selecting the pigment, dispersant, dispersion medium, setting dispersion conditions, filtering conditions, etc., and controlling the particle size of the pigment suppresses 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, a uniform and stable ink composition can be obtained even when the fine pigment is used.
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 may contain other components appropriately selected according to the purpose, in addition to the C component, the polymerizable compound and the pigment.
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 polymerization initiator for radical polymerization or cationic polymerization, and more preferably a photopolymerization initiator.

The photopolymerization initiator is a compound that undergoes 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, ultraviolet rays having a wavelength of 400 to 200 nm, far ultraviolet rays, g rays, h rays, i rays, KrF excimer laser rays, ArF excimer laser rays, electron rays, X Those having sensitivity to a beam, molecular beam, 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). Can be used. Specific examples of the photopolymerization initiator include chemically amplified photo described in Organic Electronics Materials Research Group, “Organic Materials for Imaging”, pages 187 to 192 of Bunshin Publishing (1993)). Examples include resists and compounds used for photocationic polymerization. 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, and compounds that generate bond cleavage oxidatively or reductively through interaction with the electronically excited state of the sensitizing dye.

  Among these photopolymerization initiators, (i) aromatic ketone compounds, (ii) aromatic onium salt compounds, (iii) organic peroxides, (iv) hexaarylbiimidazole compounds, (v) ketoxime ester compounds And (vi) borate compounds, (vii) azinium compounds, (viii) metallocene compounds, (ix) active ester compounds, (x) compounds having a carbon-halogen bond, and the like.

  Examples of the (i) aromatic ketone compound include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY”, J. Pat. P. FOUASSIER J.M. F. Compounds having a benzophenone skeleton or a thioxanthone skeleton described in p77 to 117 of RABEK (1993) are preferable, an α-thiobenzophenone compound described in JP-B-47-6416, and a benzoin ether compound described in JP-B-47-3981 Α-substituted benzoin compounds described in JP-B-47-22326, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, JP-B-60-26483 Dialkoxybenzophenones described in Japanese Patent Publication No. 60-26403, benzoin ethers described in JP-A No. 62-81345, Japanese Patent Publication No. 1-334242, US Pat. No. 4,318,791, European Patent No. 0284561A1 Α-amino described in No. Nzophenones, p-di (dimethylaminobenzoyl) benzene described in JP-A-2-211452, thio-substituted aromatic ketone described in JP-A-61-194062, acylphosphine sulfide described in JP-B-2-9597 And acylphosphine described in JP-B-2-9596, thioxanthones described in JP-B-63-61950, and coumarins described in JP-B-59-42864.

  Examples of the (ii) aromatic onium salt compound include elements of Group 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, 293443, 297442, 279210, and 422570, U.S. Patent Nos. 3902144, 4933377, 4760013, 4734444, and Sulfonium salts and diazonium salts described in each specification of U.S. Pat. No. 2,833,827 (benzene which may have a substituent) Azonium, 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-63-63) 142345, JP-A-63-142346, JP-B-46-42363, etc., specifically 1-methoxy-4-phenylpyridinium tetrafluoroborate, etc.), and Preferable examples include compounds described in JP-A Nos. 52-147277, 52-14278, and 52-14279. These compounds generate radicals and acids as active species.

  Examples of the (iii) organic peroxide 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, peroxide compounds such as di-t-butyldiperoxyisophthalate, and the like. It is.

  Examples of the (iv) 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 and the like are preferred.

  Examples of the (v) 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 (vi) borate compound include compounds described in US Pat. Nos. 3,567,453 and 4,343,891, European Patents 109,772 and 109,773, and the like.
Examples of the (vii) azinium compound include those disclosed in 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 (viii) metallocene compound are described in, for example, JP-A Nos. 59-152396, 61-151197, 63-41484, JP-A-2-249, and JP-A-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 (ix) active ester compound include, for example, 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 6 Compounds described in JP--14340 Patent and JP 59-174831, and the like.

  Examples of the compound (x) 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 (i) to (x) are as follows.

The said photoinitiator may be used individually by 1 type, and may use 2 or more types together.
The content of the polymerization initiator in the ink composition is preferably from 0.1 to 20 mass%, more preferably from 0.5 to 10 mass%, more preferably from 1 to 7 in terms of the total solid content of the ink composition. 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.
As specific examples of the sensitizing dye, compounds represented by the following general formulas (IX) to (XIII) are more preferable.

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 R ⁵¹ and R ⁵² may be bonded to 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 the adjacent A ² and 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.

Preferred specific 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 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.

<Evaluation of physical properties of ink composition>
-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 are preferred.
The surface tension can be measured using, for example, a Wilhelmy surface tension meter or a Du Nouy surface tension meter.

<Method for producing ink composition>
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 of ink composition>
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. .

<Image Recorded Material (Printed Material) Obtained Using the Ink Composition of the Present Invention>
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. Therefore, in addition to image recording (image formation), it can be suitably used for various applications such as formation of an ink receiving layer (image portion) of a lithographic printing plate.
What was obtained by curing the ink composition of the present invention is the printed material of the present invention. The printed material is a material obtained by ejecting and curing the ink composition of the present invention on the recording medium. 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 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 is a high image, has excellent weather resistance, and can be suitably used in a wide range of fields.

<Inkjet recording using ink composition>
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, discharging from the ink nozzle head is preferable from the viewpoint of excellent 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. It is possible to irradiate the actinic radiation before the ink composition penetrates to a deep part where the light source does not reach, to suppress the remaining of unreacted monomer, and as a result, it is possible to reduce odor. 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. This is advantageous in that the dot diameter of the composition can be kept constant and high image quality can be obtained. In addition, in order to obtain a color image, it is preferable to superimpose in order from an ink of a color with low brightness (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 of ink composition-
The ink composition of the present invention is cured by being irradiated with actinic radiation after image recording, and the irradiation conditions of the actinic radiation in this case are not particularly limited and are appropriately selected according to the purpose. be able to.
The irradiation method of active radiation is described in, for example, Japanese Patent Application Laid-Open No. 60-132767. Specifically, light sources are provided on both sides of the head unit, and the head and the light source are scanned by a shuttle method. 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 of irradiating UV light to a recording unit by applying a method using an optical fiber or 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 the ink composition of the present invention is ejected to record an image 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.

Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “part” represents “part by mass”.
-Synthesis of mercaptan compound represented by formula (2)-
As shown below, chain transfer agents B-1 to B-11 (mercaptan compounds represented by the general formula (2) described above) were synthesized.

(Synthesis Example B-1)
Dipentaerythritol hexakis (3-mercaptopropionate) [DPMP; manufactured by Sakai Chemical Industry Co., Ltd.] 7.83 parts, and 14.01 parts of compound (M-1) having the following carbon-carbon double bond , Dissolved in 87.36 parts of dimethylformamide and heated to 70 ° C. under a nitrogen stream. To this, 0.06 part of 2,2′-azobis (2,4-dimethylvaleronitrile) [V-65, manufactured by Wako Pure Chemical Industries, Ltd.] was added and heated for 3 hours. Furthermore, 0.06 part of V-65 was added and reacted at 70 ° C. for 3 hours under a nitrogen stream. By cooling to room temperature, a 20% solution of a mercaptan compound (chain transfer agent B-1) shown below was obtained.
B-1 (1/5 adduct)

(Synthesis Example B-2)
In Synthesis Example B-1, 14.01 parts of compound (M-1) having a carbon-carbon double bond and 87.36 parts of dimethylformamide are combined with compound (M-2) having the following carbon-carbon double bond. Except having changed into 22.43 parts and 121.04 parts of dimethylformamide, it carried out similarly to the said synthesis example B-1, and obtained the 20% solution of the mercaptan compound (chain transfer agent B-2) shown below.
B-2 (1/5 adduct)

(Synthesis Example B-3)
In Synthesis Example B-1, 14.01 parts of compound (M-1) having a carbon-carbon double bond and 87.36 parts of dimethylformamide are combined with compound (M-3) having the following carbon-carbon double bond. Except having changed into 13.31 parts and dimethylformamide 84.57 parts, it carried out similarly to the said synthesis example B-1, and obtained the 20% solution of the mercaptan compound (chain transfer agent B-3) shown below.
B-3 (1/5 adduct)

(Synthesis Example B-4)
4.89 parts of pentaerythritol tetrakis (3-mercaptopropionate) [PEMP; manufactured by Sakai Chemical Industry Co., Ltd.] and 12.70 parts of compound (M-4) having the following carbon-carbon double bond The product was dissolved in 70.36 parts of formamide and heated to 70 ° C. under a nitrogen stream. To this, 0.04 part of 2,2′-azobis (2,4-dimethylvaleronitrile) [V-65, manufactured by Wako Pure Chemical Industries, Ltd.] was added and heated for 3 hours. Further, 0.04 part of V-65 was added and reacted at 70 ° C. for 3 hours under a nitrogen stream. By cooling to room temperature, a 20% solution of a mercaptan compound (chain transfer agent B-4) shown below was obtained.
B-4 (1/3 adduct)

(Synthesis Example B-5)
In Synthesis Example B-1, 14.01 parts of compound (M-1) having a carbon-carbon double bond and 87.36 parts of dimethylformamide are combined with compound (M-5) having the following carbon-carbon double bond. Except having changed to 19.72 parts and dimethylformamide 110.20 parts, it carried out similarly to the said synthesis example B-1, and obtained the 20% solution of the mercaptan compound (chain transfer agent B-5) shown below.
B-5 (1/5 adduct)

(Synthesis Example B-6)
In Synthesis Example B-1, 14.01 parts of compound (M-1) having a carbon-carbon double bond and 87.36 parts of dimethylformamide are combined with compound (M-6) having the following carbon-carbon double bond. A 20% solution of a mercaptan compound (chain transfer agent B-6) shown below was obtained in the same manner as in Synthesis Example B-1, except that the amount was changed to 21.38 parts and 116.82 parts of dimethylformamide.
B-6 (1/5 adduct)

(Synthesis Example B-7)
In Synthesis Example B-1, 14.01 parts of compound (M-1) having a carbon-carbon double bond and 87.36 parts of dimethylformamide are combined with compound (M-7) having the following carbon-carbon double bond. A 20% solution of a mercaptan compound (chain transfer agent B-7) shown below was obtained in the same manner as in Synthesis Example B-1, except that the amount was changed to 21.87 parts and 118.82 parts of dimethylformamide.
B-7 (1/5 adduct)

(Synthesis Example B-8)
In Synthesis Example B-1, 14.01 parts of compound (M-1) having a carbon-carbon double bond and 87.36 parts of dimethylformamide are combined with compound (M-8) having the following carbon-carbon double bond. Except having changed to 23.28 parts and dimethylformamide 124.43 parts, it carried out similarly to the said synthesis example B-1, and obtained the 20% solution of the mercaptan compound (chain transfer agent B-8) shown below.
B-8 (1/5 adduct)

(Synthesis Example B-9)
In the synthesis example B-4, 12.70 parts of a compound (M-4) having a carbon-carbon double bond and 70.36 parts of dimethylformamide are added to the compound (M-1) having the following carbon-carbon double bond. A 20% solution of a mercaptan compound (chain transfer agent B-9) shown below was obtained in the same manner as in Synthesis Example B-4 except that the amount was changed to 8.41 parts and 53.20 parts of dimethylformamide.
B-9 (1/3 adduct)

(Synthesis Example B-10)
In Synthesis Example B-1, 14.01 parts of compound (M-1) having a carbon-carbon double bond and 87.36 parts of dimethylformamide are combined with compound (M-1) having the following carbon-carbon double bond. Except having changed to 11.21 parts and dimethylformamide 76.16 parts, it carried out similarly to the said synthesis example B-1, and obtained the 20% solution of the mercaptan compound (chain transfer agent B-10) shown below.
B-10 (1/4 adduct)

(Synthesis Example B-11)
In Synthesis Example B-1, 14.01 parts of compound (M-1) having a carbon-carbon double bond and 87.36 parts of dimethylformamide are combined with compound (M-9) having the following carbon-carbon double bond. A 20% solution of a mercaptan compound (chain transfer agent B-11) shown below was obtained in the same manner as in Synthesis Example B-1, except that the amount was changed to 25.92 parts and dimethylformamide 135.02 parts.
B-11 (1/5 adduct)

<Synthesis of the C component>
Next, the C component (C-1 to C-15) of the present invention was synthesized.

(Synthesis Example C-1)
A mixed solution of 109 parts of a 20% solution of chain transfer agent B-1 obtained in Synthesis Example B-1 and 50 parts of methyl methacrylate (MMA; monomer) was heated to 80 ° C. under a nitrogen stream. To this, 0.033 part of 2,2′-azobis (isobutyronitrile) [AIBN, manufactured by Wako Pure Chemical Industries, Ltd.] was added, heated for 3 hours, then added again with 0.033 part of AIBN, And reacted at 80 ° C. for 3 hours. Then, it cooled to room temperature and diluted with acetone. After reprecipitation using a large amount of methanol, vacuum drying was performed to obtain 50 parts of the following polymer (C-1: polystyrene equivalent weight average molecular weight 14,000 (measured by GPC)).
C-1 (n = 5, m = 1)

(Synthesis Example C-2)
In Synthesis Example C-1, except that 50 parts of methyl methacrylate was changed to 63 parts of butyl methacrylate and 6.5 parts of 2-hydroxyethyl methacrylate, the same as in Synthesis Example C-1, the following 65 parts of solids of a polymer (C-2: polystyrene equivalent weight average molecular weight 16,000 (measured by GPC)) were obtained.
C-2 (n = 5, m = 1)

(Synthesis Examples C-3 to C-15)
In Synthesis Example C-1, except that the chain transfer agent, the type and amount of monomer, the amount of AIBN, and the reprecipitation method were changed as shown in Table 1 below, the same as in Synthesis Example C-1, The following polymers (C-3 to C-15) were obtained. In addition, the weight average molecular weight in Table 1 was measured by GPC.

The structure of the synthesized polymer is shown below. The display such as C-3 indicates the number of the synthesis example in Table 1.
C-3 (n = 5, m = 1)
C-4 (n = 5, m = 1)
C-5 (n = 5, m = 1)
C-6 (n = 3, m = 1)
C-7 (n = 5, m = 1)
C-8 (n = 5, m = 1)
C-9 (n = 5, m = 1)
C-10 (n = 5, m = 1)
C-11 (n = 5, m = 1)
C-12 (n = 3, m = 1)
C-13 (n = 3, m = 1)
C-14 (n = 4, m = 2)
C-15 (n = 5, m = 1)

Example 1
The synthesized polymer C-1 is dissolved in the following polymerizable compounds (i) and (ii) <the component (A)>, and together with the pigment <the component (B)>, a motor mill M50 (manufactured by Eiger). ), And zirconia beads having a diameter of 0.65 mm were used and dispersed at a peripheral speed of 9 m / s 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.
Polymer C-1 ... 1.5g
Polymerizable compound:
(I) Neopentyl glycol propylene oxydiacrylate (NPGPODA: manufactured by Sartomer Co., Ltd.) ... 60.0 g
(Ii) Captolactone-modified dipentaerythritol hexaacrylate (DPCA-60: Nippon Kayaku Co., Ltd.) 27.5 g
Quinacridone pigment (PV-19) ... 5g
Polymerization initiator (acylphosphine oxide compound (Lucirin TPO-L: BA
SF)) ... 5.0g

(Examples 2 to 15)
In Example 1, the active energy ray-curable inkjet inks of Examples 2 to 15 were the same as Example 1 except that the polymer C-1 was changed to the synthesized polymers C-2 to C-15, respectively. (Ink composition of the present invention) was produced.

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

(Examples 16 to 21 and Comparative Examples 3 to 4)
In Examples 1, 2, 4, 5, 9, 13, and Comparative Examples 1 and 2, except that the quinacridone pigment (PV-19) was changed to a pigment (PY-128, manufactured by Clariant), Examples In the same manner as in 1, 2, 4, 5, 9, 13, and Comparative Examples 1 and 2, inkjet ink compositions of Examples 16 to 21 and Comparative Examples 3 to 4 were produced.

(Examples 22 to 27 and Comparative Examples 5 to 6)
The same as in Examples 1, 2, 4, 5, 9, 13, and Comparative Examples 1 and 2, except that the quinacridone pigment (PV-19) was changed to a pigment (PO-36: manufactured by Albion Colors). The inkjet ink compositions of Examples 22 to 27 and Comparative Examples 5 to 6 were produced in the same manner as in Examples 1, 2, 4, 5, 9, 13, and Comparative Examples 1 and 2.

(Examples 28-33 and Comparative Examples 7-8)
In Examples 1, 2, 4, 5, 9, 13, and Comparative Examples 1 and 2, Examples 1, 2, 4, 5, 9, except that the polymerizable compound and the polymerization initiator were changed as follows. 13 In the same manner as in Comparative Examples 1 and 2, inkjet inks of Examples 28 to 33 and Comparative Examples 7 to 8 were produced.
Polymerizable compound (i) Oxetane compound (OXT-221: manufactured by Toa Gosei Co., Ltd.)
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 70.0g
(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 34 to 39 and Comparative Examples 9 to 10)
In Examples 28 to 33 and Comparative Examples 7 to 8, Examples 28 to 33 and Comparative Examples 7 to 8 were used except that the quinacridone pigment PV-19 was changed to phthalocyanine pigment PB15: 3 (manufactured by Ciba Specialty Chemicals). In the same manner, inkjet inks of Examples 34 to 39 and Comparative Examples 9 to 10 were produced.

(Examples 40 to 45 and Comparative Examples 11 to 12)
In Examples 1, 2, 4, 5, 9, 13, and Comparative Examples 1 and 2, Examples 1, 2, 4, except that the polymerizable compound, the polymerization initiator, and the pigment were changed as follows. In the same manner as in Examples 5, 9, and 13 and Comparative Examples 1 and 2, inkjet inks of Examples 40 to 45 and Comparative Examples 11 to 12 were produced.

(1) 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.) 60.0 g
(2) Pigment:
Acetron pigment (PY-120: manufactured by Clariant) ... 4.0 g
(3) Polymerization initiator:
Acylphosphine oxide compound (Lucirin TPO-L: BASF)
Made) ... 5.0g

(Examples 46 to 51 and Comparative Examples 13 to 14)
In Examples 40 to 45 and Comparative Examples 11 and 12, Example 40 was changed except that the polymerizable compound, the polymerization initiator, and the pigment were changed as follows, and the amount of the polymer used was changed to 1.0 g. To 45 and Comparative Examples 11 and 12, inkjet inks of Examples 46 to 51 and Comparative Examples 13 to 14 were produced.
(1) Polymerizable compound:
(I) propoxylated neopentyl glycol diacrylate (NPGPODA: manufactured by Sartomer Co., Ltd.) 31.0 g
(Ii) Dipropylene glycol diacrylate (DPGDA: manufactured by Daicel Cytec Co., Ltd.) 60.0 g
(2) Pigment:
Dioxazine pigment (PV-23: manufactured by Clariant) ... 3.0 g
(3) Polymerization initiator:
Acylphosphine oxide compound (Lucirin TPO-L: BASF)
Made) ... 5.0g

(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>
The dispersion state after each ink composition was stored at 25 ° C. for 1 month and stored at 70 ° C. for 24 hours 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 slightly increases, 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, 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 printed image was irradiated with ultraviolet rays as actinic radiation under the condition that the recorded image had an energy of 100 mJ / cm ² .
The obtained printed matter was touched with a finger, and the presence or absence of stickiness was evaluated according to the following criteria.
A: No stickiness B: Slightly sticky C: Remarkably sticky

From Tables 2 to 4, 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 has high sensitivity to irradiation with active radiation (ultraviolet rays). It is possible to record a high-quality image (printed material of the present invention) that is hardened and is not sticky, and even under long-term storage conditions, the viscosity of the pigment does not increase and the dispersibility of the pigment does not occur. The dispersion stability was found to be good.
On the other hand, in the case of the ink of the comparative example using a commercially available polymer dispersant, the storage stability (stability (60 ° C.)) under high temperature conditions was inferior, and it was at a level causing a practical problem.
In the above examples, the synthesized polymer is composed of a terminal pigment interaction site and a polymer chain, and the polymer chain has a higher affinity for the dispersion medium than the pigment, and particles in the dispersion liquid. It was considered that they acted or functioned as a steric repulsive group that sterically prevented aggregation of each other. In the present invention, the polymer described above has the same configuration as the polymer used in the above examples, and therefore it is presumed that the polymer has the same action or function as the polymer used in each of the above examples. The

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 printed material, and is also suitable for the production of resists, color filters, and optical disks. It is also useful as an optical modeling material. In addition, by applying the ink jet recording method, a high-quality image can be directly formed on a non-absorbable recording medium based on digital data. It is also suitably used for production.
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 printed matter of the present invention is obtained using the ink composition of the present invention, the printed matter is excellent in durability with high image quality, and thus is widely used in various applications.

Claims (9)

An ink composition comprising at least a polymerizable compound, a pigment, and a polymer represented by the following general formula (1).
In the general formula (1), R ¹ and R ² represent a monovalent substituent. R ³ represents an (m + n) -valent organic linking group, R ⁴ represents a single bond or an (a + 1) -valent organic linking group, and R ⁵ represents either a single bond or a divalent organic linking group. Represent. a represents 1 to 10, m represents 1 to 8, n represents 2 to 9, and m + n is 3 to 10. P represents a polymer backbone. The m Ps may be the same or different.   The polymer skeleton represented by P is a vinyl monomer polymer, a vinyl monomer copolymer, an ester polymer, an ether polymer, a urethane polymer, an amide polymer, an epoxy polymer, a silicone polymer, and these The ink composition according to claim 1, wherein the ink composition is derived from at least one selected from the group consisting of a modified product and a copolymer.   The ink composition according to claim 1, comprising a polymerization initiator.   The ink composition according to claim 3, wherein the polymerizable compound is a radical polymerizable compound, and the polymerization initiator is a photo radical generator.   The ink composition according to claim 3, 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 discharge step of discharging the ink composition according to claim 1 onto a recording medium, and a curing step of curing the discharged ink composition by irradiation with actinic radiation. Image recording method.   A printed matter obtained by curing the ink composition according to claim 1.   The printed material according to claim 8, wherein the ink composition is ejected onto a recording medium by an ink jet printer, and then the activated ink is irradiated to cure the ejected ink composition.