JP2006328257A - Ink composition, image forming method using the same and recorded matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the curability by irradiation of an active energy ray and to enable forming an image excellent in lightfastness. <P>SOLUTION: The ink composition comprises a cationic azo compound as a colorant. Preferably the cationic azo compound is represented by general formula (1), wherein R<SP>1</SP>-R<SP>3</SP>: H or a substituent (such as alkyl group, aryl group, alkoxy group and aryloxy group); R<SP>4</SP>: H, an alkyl group or aryl group; X: CR<SP>5</SP>or N; Y: NR<SP>6</SP>R<SP>7</SP>, SR<SP>8</SP>or OR<SP>9</SP>; Z: O, S or NR<SP>10</SP>; R<SP>5</SP>: H or a substituent (such as an alkyl group, aryl group, alkoxy group and aryloxy group); R<SP>6</SP>-R<SP>10</SP>: H, an alkyl group or aryl group; ring B: a 5-member ring; and A<SP>-</SP>: a pair anion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink composition, an image forming method using the same, and a recorded matter, and more specifically, an ink composition which can be polymerized and cured after recording and is suitable for robust image recording, and an image using the same. The present invention relates to a forming method and recorded matter.

  As an image recording method for forming an image on a recording material such as paper based on an image data signal, an electrophotographic method, a sublimation type or melt type thermal transfer method, an ink jet recording method, and the like are known. In particular, the ink jet recording method is capable of recording with an inexpensive apparatus and ejects ink only to a required image portion to form an image directly on a recording material, so that the ink can be used efficiently. The running cost is also cheap. Furthermore, there is little noise and it has excellent performance as an image recording method.

  However, according to the ink jet recording method, it is possible to print not only on plain paper but also on a non-water-absorbing recording material such as a plastic sheet and a metal plate, but the light resistance of the printed image, specifically, the image is formed. The light resistance of dyes to be used is an important issue. In particular, in the magenta wavelength region, light resistance tends to be inferior to that of the prior art.

  As one of the ink jet recording methods, there is a recording method using an ink for ink jet recording that can be cured by irradiation with active rays. According to this recording method, it is possible to form a sharp image by irradiating radiation immediately after printing and curing the ink droplets. However, the curing speed is improved in terms of shortening the time required for printing. It has become a challenge.

In view of the above, a means using a pigment has been proposed for the purpose of improving the light resistance of a dye after printing (see, for example, Patent Documents 1 and 2). However, since the pigment is a fine particle, It is necessary to stabilize the dispersion state, a step of dispersing fine particles in the production process is indispensable, and a large amount of a dispersion stabilizer must be added.
In addition, since the pigment is a fine particle, there are many problems such as light scattering and the like resulting in a slow curing speed when irradiated with active rays for curing.

On the other hand, when an oil-soluble dye is used as a colorant, the dye is present in a soluble state in the ink droplets, so the process for dispersion is omitted, and the use of a dispersion stabilizer or the like Is not necessary, and there is a merit that it is not affected by scattering accompanying fine particles (see, for example, Patent Documents 3 to 6).
The improvement in the curing rate has not been improved yet.
JP 2003-300315 A JP 2004-42429 A JP 2003-221529 A JP 2003-221530 A JP 2004-175874 A JP 2004-175876 A

However, many oil-soluble dyes so far have absorption in the wavelength region (ultraviolet to yellow region) of the active energy rays irradiated during curing, and there is a problem that it is difficult to cure. Further, as described above, when it is attempted to improve the light fastness of the dye in the magenta region, the color of the dye itself changes, and as a result, it cannot be used as a colorant.
Accordingly, an ink composition that has excellent curability and light resistance (particularly light resistance in the magenta region) has not yet been provided, and the curability and light resistance of the ink composition are improved. Was demanded.

  The present invention has been made in view of the above, and an ink composition capable of forming an image having excellent curability by irradiation with active energy rays and excellent light resistance (particularly light resistance in a magenta region). In addition, an object of the present invention is to provide an image forming method capable of forming an image with high light fastness that can be cured at high speed by irradiation with an active energy ray, and to provide a high hardness and high light fastness recorded matter. This is the issue.

In the present invention, a cationic azo compound (particularly having a specific structure) is selectively used as a colorant, so that the colored composition can be cured with active energy rays at high speed and light resistance after curing. It has been obtained based on the knowledge that it is effective to improve the performance. That is, cationic azo compounds, particularly those having a specific structure, do not have absorption in the region close to the active energy ray necessary for curing, specifically in the vicinity of a wavelength of 300 to 400 nm, so that the curability is good and high-speed curing is achieved. It is suitable and has an oxidation potential higher than that of a neutral azo compound, hardly causes inhibition of curing, and is effective for improving fading resistance due to light or the like and curing characteristics.
Specific means for achieving the above object are as follows.

  <1> An ink composition comprising a cationic azo compound, a polymerizable compound, and a polymerization initiator.

  <2> The ink composition according to <1>, wherein the cationic azo compound is a compound represented by the following general formula (1).

In the general formula (1), R ¹ , R ² , and R ³ each independently represent a hydrogen atom or a substituent. R ⁴ represents a hydrogen atom, an alkyl group, or an aryl group. X represents CR ⁵ or a nitrogen atom, Y represents NR ⁶ R ⁷ , SR ⁸ , or OR ⁹ , and Z represents an oxygen atom, a sulfur atom, or NR ¹⁰ . R ⁵ represents a hydrogen atom or a substituent. R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, an alkyl group or an aryl group. Ring B represents a saturated or unsaturated hetero 5-membered ring together with a nitrogen atom, a carbon atom, and Z, and the hetero 5-membered ring may be condensed. A ⁻ represents a counter anion, and A ⁻ and R ^{1 to} R ¹⁰ may be linked to each other. R ¹ and R ² , R ² and R ⁶ , R ⁵ and R ³ , R ⁶ and R ⁷ , R ² and R ⁸ , R ² and R ⁹ may be connected to each other to form a ring.

<3> The substituent represented by R ¹ , R ² , or R ³ is an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylsulfonyl group, an arylsulfonyl group, an alkylthio group, an arylthio group, or a cyano group. , Acyl group, carbamoyl group, sulfamoyl group, amino group, alkoxycarbonylamino group, alkoxysulfonylamino group, carbamoylamino group, sulfamoylamino group, hydroxyl group, carboxylic acid group, sulfonic acid group, nitro group, halogen atom, or It is an ink composition as described in said <2> which is a heterocyclic group.

<4> The substituent represented by R ⁵ is an alkyl group, aryl group, alkoxy group, aryloxy group, alkylsulfonyl group, arylsulfonyl group, alkylthio group, arylthio group, cyano group, acyl group, carbamoyl group, <2> or <, which is a sulfamoyl group, an amino group, an alkoxycarbonylamino group, an alkoxysulfonylamino group, a carbamoylamino group, a sulfamoylamino group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, a nitro group, or a halogen atom 3>.

<5> The ink composition according to any one of <2> to <4>, wherein Y in the general formula (1) is NR ⁶ R ⁷ .
<6> The ink composition according to any one of <2> to <5>, wherein Z is NR ¹⁰ in the general formula (1).
<7> The ink composition according to <6>, wherein R ¹⁰ is an aryl group.

<8> The ink composition according to any one of <2> to <7>, wherein X in the general formula (1) is a nitrogen atom.
<9> The ink composition according to any one of <2> to <8>, wherein in formula (1), ring B is a saturated complex 5-membered ring.
<10> The ink composition according to any one of <1> to <9>, wherein an oxidation potential of the cationic azo compound is nobler than 1.0 V (vs SCE).

<11> The ink composition according to any one of <1> to <10>, wherein the polymerizable compound is a radical polymerizable monomer.
<12> The ink composition according to any one of <1> to <11>, wherein the polymerization initiator is a photopolymerization initiator.
<13> The ink composition according to any one of <1> to <12>, which is used for inkjet recording.

<14> An image forming method, wherein an image is inkjet-recorded on a recording material using the ink composition according to any one of <1> to <13>.
<15> An image forming method, wherein an image formed using the ink composition according to any one of <1> to <13> is cured by irradiation with active energy rays.
<16> A recording step of recording an image on a recording material using the ink composition according to any one of <1> to <13>, and curing the recorded image by irradiating active energy rays An image forming method comprising: a curing step.
<17> The image forming method according to <16>, wherein the recording step includes inkjet recording of the image by discharging the ink composition.
<18> A recorded matter comprising the ink composition according to any one of <1> to <13>.

  According to the present invention, an ink composition capable of forming an image having excellent curability by irradiation with active energy rays and having excellent light resistance (particularly light resistance in a magenta region), and active energy rays. It is possible to provide an image forming method capable of performing curing by irradiation at high speed and forming a high light fastness image, and a high hardness and high light fastness recorded matter.

  Hereinafter, the ink composition of the present invention, and the image forming method and recorded matter using the ink composition will be described in detail.

  The ink composition of the present invention comprises a cationic azo compound, a polymerizable compound, and a polymerization initiator, and can be constituted using other components as necessary. This ink composition is a composition in which a polymerization initiating species generated from a polymerization initiator acts on a polymerizable compound and is cured by application of active energy rays (hereinafter also referred to as “active radiation”).

Here, the active energy ray is not particularly limited as long as it can impart energy capable of generating a polymerization initiating species that initiates polymerization of a polymerizable compound from a polymerization initiator in the ink composition by irradiation. For example, ultraviolet rays, far ultraviolet rays, visible rays, g rays, h rays, i rays, KrF excimer laser rays, ArF excimer laser rays, electron rays, X rays, molecular rays, ion beams, α rays, γ rays, etc. included. Among these, from the viewpoint of curing sensitivity and device availability, ultraviolet rays or electron beams are preferable, and ultraviolet rays (wavelength 200 to 400 nm) are particularly preferable. Alternatively, the ink composition of the present invention may be an ink composition that is cured by generating a polymerization initiating species by heating.
Among the above, the ink composition of the present invention preferably has an ink composition that can be cured by irradiating ultraviolet rays as active energy rays.

The ink composition of the present invention is useful for normal printing applications and can form sharp images with excellent color developability, not only providing high-quality printed matter, but also for producing resists, color filters, and optical disks. It is useful and also useful as an optical modeling material.
In addition, the ink composition of the present invention has an appropriateness capable of directly forming a high-quality image on a non-absorbable recording material based on digital data by applying an inkjet recording method to image recording, It is suitable for production of printed matter with a large area.

Hereafter, each component which comprises the ink composition of this invention is demonstrated sequentially.
(Cationic azo compound)
The ink composition of the present invention contains at least one cationic azo compound as a colorant. This cationic azo compound has a low absorption in a region close to the active energy ray necessary for curing, specifically in the vicinity of a wavelength of 300 to 400 nm, and has a higher oxidation potential than a neutral azo compound, and inhibits curing. Since it is a compound that does not easily occur, good curability can be obtained, high-speed curing is possible, and resistance to actinic radiation (particularly light resistance) can be effectively improved.

  In the present invention, the cationic azo compound includes both a dye and a pigment, and is preferably a dye.

As the cationic azo compound, a compound represented by the following general formula (1) is particularly preferable. This compound has a structure in which a cation moiety (N ⁺ ) is introduced at a position adjacent to a carbon bonded to an azo group in a hetero 5-membered ring, and compared with a conventionally known neutral azo compound, This is effective for improving the curability and light resistance of the ink composition. In particular, it is suitable as a colorant in a magenta region (a wavelength region of 480 to 600 nm).

In the general formula (1), R ¹ , R ² , and R ³ each independently represent a hydrogen atom or a substituent, and the substituent represented by R ¹ , R ² , or R ³ is particularly limited. However, the alkyl group, aryl group, alkoxy group, aryloxy group, alkylsulfonyl group, arylsulfonyl group, alkylthio group, arylthio group, cyano group, acyl group are preferable. Group, carbamoyl group, sulfamoyl group, amino group, alkoxycarbonylamino group, alkoxysulfonylamino group, carbamoylamino group, sulfamoylamino group, hydroxyl group, carboxylic acid group, sulfonic acid group, nitro group, halogen atom, or heterocyclic ring It is a group. R ⁴ represents a hydrogen atom, an alkyl group, or an aryl group. X represents CR ⁵ or a nitrogen atom, Y represents NR ⁶ R ⁷ , SR ⁸ , or OR ⁹ , and Z represents an oxygen atom, a sulfur atom, or NR ¹⁰ .

R ⁵ represents a hydrogen atom or a substituent, and the substituent represented by R ⁵ is not particularly limited, and can exert the effects of the present invention, but preferably an alkyl group, an aryl group, Alkoxy group, aryloxy group, alkylsulfonyl group, arylsulfonyl group, alkylthio group, arylthio group, cyano group, acyl group, carbamoyl group, sulfamoyl group, amino group, alkoxycarbonylamino group, alkoxysulfonylamino group, carbamoylamino group, It represents a sulfamoylamino group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, a nitro group, or a halogen atom. R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, an alkyl group or an aryl group.

The alkyl group represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , or R ¹⁰ may be unsubstituted or have a substituent. Well, for example, methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, isobutyl group, tertiary butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, tertiary octyl Preferred examples include a group, 2-ethylhexyl group, decyl group, dodecyl group, octadecyl group and the like.

  As the substituent when the alkyl group further has a substituent, a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, A sulfonic acid group and a heterocyclic group are preferable, and a methyl group is more preferable.

Among the above, the alkyl group represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , or R ¹⁰ is an alkyl group having 1 to 20 carbon atoms. Preferred is an alkyl group having 1 to 15 carbon atoms, more preferred is an alkyl group having 1 to 10 carbon atoms, and a methyl group, isopropyl group, normal butyl group, tertiary butyl group, heptyl group, and octyl group are particularly preferred. .

The aryl group represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , or R ¹⁰ may be unsubstituted or substituted. An aryl group having 6 to 25 carbon atoms is preferable, an aryl group having 6 to 10 carbon atoms is more preferable, and an unsubstituted or substituted phenyl group is more preferable. When the aryl group has a substituent, examples of the substituent include an alkyl group, a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxylic group. An acid group, a sulfonic acid group, a heterocyclic group and the like are preferable.

Among the above, the aryl group represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , or R ¹⁰ is particularly a phenyl group, 4-chlorophenyl. Group, 4-dimethylaminophenyl group, 2,4,6-trimethylphenyl group and 2,6-isopropylphenyl group are preferred.

The alkoxy group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, and examples thereof include a methoxy group, an ethoxy group, a normal propyloxy group, and an isopropyloxy group. Normal butyloxy group, isobutyloxy group, tertiary butyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, heptyloxy group, octyloxy group, tertiary octyloxy group, 2-ethylhexyloxy Preferred examples include a group, a decyloxy group, a dodecyloxy group, an octadecyloxy group, a 1-ethylpropyloxy group, or a 2-methyl-4,4-dimethylpentyloxy group.

  Examples of the substituent when the alkoxy group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxylic acid. Group, sulfonic acid group and heterocyclic group are preferred.

Among the above, the alkoxy group represented by R ¹ , R ² , R ³ , or R ⁵ is preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 15 carbon atoms, and a methoxy group , A pentyloxy group, an octyloxy group, and a 2-methyl-4,4-dimethylpentyloxy group are particularly preferable.

The aryloxy group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, and is preferably an aryloxy group having 6 to 25 carbon atoms. 6-10 aryloxy groups are more preferred, and unsubstituted or substituted phenoxy groups are more preferred. Examples of the substituent when the aryloxy group further has a substituent include an alkyl group, a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, and a cyano group. Group, carboxylic acid group, sulfonic acid group, heterocyclic group and the like are preferable.

Among the above, the aryloxy group represented by R ¹ , R ² , R ³ , or R ⁵ is particularly preferably a phenoxy group.

The alkylsulfonyl group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, and examples thereof include a methylsulfonyl group, an ethylsulfonyl group, a normal propylsulfonyl group, Isopropylsulfonyl group, normal butylsulfonyl group, isobutylsulfonyl group, tertiary butylsulfonyl group, pentylsulfonyl group, cyclopentylsulfonyl group, hexylsulfonyl group, cyclohexylsulfonyl group, heptylsulfonyl group, octylsulfonyl group, tertiary octylsulfonyl group, 2 -An ethylhexyl sulfonyl group, a decyl sulfonyl group, a dodecyl sulfonyl group, or an octadecyl sulfonyl group etc. are mentioned suitably.

  Examples of the substituent in the case where the alkylsulfonyl group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxyl group. An acid group, a sulfonic acid group, and a heterocyclic group are preferable.

Among the above, the alkylsulfonyl group represented by R ¹ , R ² , R ³ , or R ⁵ is preferably an alkylsulfonyl group having 1 to 20 carbon atoms, and more preferably an alkylsulfonyl group having 1 to 15 carbon atoms. Further, an alkylsulfonyl group having 1 to 10 carbon atoms is more preferable, and a methylsulfonyl group is particularly preferable.

The arylsulfonyl group represented by R ¹ , R ² or R ³ may be unsubstituted or substituted, and is preferably an arylsulfonyl group having 6 to 25 carbon atoms, preferably 6 to 10 carbon atoms. The arylsulfonyl group is more preferably an unsubstituted or substituted phenylsulfonyl group. Examples of the substituent when the arylsulfonyl group further has a substituent include an alkyl group, a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, and a cyano group. Group, carboxylic acid group, sulfonic acid group, heterocyclic group and the like are preferable.

Among the above, the arylsulfonyl group represented by R ¹ , R ² , R ³ , or R ⁵ is particularly preferably a 4-methylphenylsulfonyl group.

The alkylthio group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, and examples thereof include a methylthio group, an ethylthio group, a normal propylthio group, and an isopropylthio group. , Normal butylthio group, isobutylthio group, tertiary butylthio group, pentylthio group, cyclopentylthio group, hexylthio group, cyclohexylthio group, heptylthio group, octylthio group, tertiary octylthio group, 2-ethylhexylthio group, decylthio group , Dodecylthio group, octadecylthio group, and the like.

  Examples of the substituent when the alkylthio group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxylic acid. Group, sulfonic acid group and heterocyclic group are preferred.

Among the above, the alkylthio group represented by R ¹ , R ² , R ³ , or R ⁵ is preferably an alkylthio group having 1 to 20 carbon atoms, more preferably an alkylthio group having 1 to 15 carbon atoms, 1-10 alkylthio groups are more preferable, and a methylthio group and an ethylthio group are particularly preferable.

The arylthio group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, and is preferably an arylthio group having 6 to 25 carbon atoms. 15 arylthio groups are more preferable, and an unsubstituted or substituted phenylthio group is more preferable. Examples of the substituent when the arylthio group further has a substituent include an alkyl group, a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, and a cyano group. A carboxylic acid group, a sulfonic acid group, a heterocyclic group and the like are preferable.

Among the above, the arylthio group represented by R ¹ , R ² , R ³ , or R ⁵ is particularly preferably a 4-methylphenylthio group.

The acyl group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, and examples thereof include a methylcarbonyl group, an ethylcarbonyl group, a normal propylcarbonyl group, isopropyl Carbonyl group, normal butylcarbonyl group, isobutylcarbonyl group, tertiary butylcarbonyl group, pentylcarbonyl group, cyclopentylcarbonyl group, hexylcarbonyl group, cyclohexylcarbonyl group, heptylcarbonyl group, octylcarbonyl group, tertiary octylcarbonyl group, 2- Preferable examples include ethylhexylcarbonyl group, decylcarbonyl group, dodecylcarbonyl group, octadecylcarbonyl group, 1-ethylpropylcarbonyl group, 2-methyl-4,4-dimethylpentylcarbonyl group and the like.

  Examples of the substituent when the acyl group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxylic acid. Group, sulfonic acid group and heterocyclic group are preferred.

Among the above, as the acyl group represented by R ¹ , R ² , or R ³ , an acyl group having 1 to 20 carbon atoms is preferable, an acyl group having 1 to 15 carbon atoms is more preferable, and a methylcarbonyl group is particularly preferable. preferable.

The carbamoyl group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, for example, methyl carbamoyl group, ethyl carbamoyl group, normal propyl carbamoyl group, isopropyl Carbamoyl group, normal butyl carbamoyl group, isobutyl carbamoyl group, tertiary butyl carbamoyl group, pentyl carbamoyl group, cyclopentyl carbamoyl group, hexyl carbamoyl group, cyclohexyl carbamoyl group, heptyl carbamoyl group, octyl carbamoyl group, tertiary octyl carbamoyl group, 2- Ethylhexylcarbamoyl group, dimethylcarbamoyl group, diethylcarbamoyl group, dinormalpropylcarbamoyl group, diisopropylcarbamoyl group, dinormalbutylcarbamoyl group, etc. Preferably they exemplified.

  Examples of the substituent when the carbamoyl group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxylic acid. Group, sulfonic acid group and heterocyclic group are preferred.

Of the above, the carbamoyl group represented by R ¹ , R ² , R ³ , or R ⁵ is preferably an aminocarbonyl group having 1 to 20 carbon atoms, more preferably a carbamoyl group having 1 to 15 carbon atoms, A carbamoyl group is particularly preferred.

The sulfamoyl group represented by R ¹ , R ² , R ³ , and R ⁵ may be unsubstituted or substituted, and examples thereof include a methylsulfamoyl group, an ethylsulfamoyl group, and normal propyl. Sulfamoyl group, isopropylsulfamoyl group, normal butylsulfamoyl group, isobutylsulfamoyl group, tertiary butylsulfamoyl group, pentylsulfamoyl group, cyclopentylsulfamoyl group, hexylsulfamoyl group, Cyclohexylsulfamoyl group, heptylsulfamoyl group, octylsulfamoyl group, tertiary octylsulfamoyl group, 2-ethylhexylsulfamoyl group, dimethylsulfamoyl group, diethylsulfamoyl group, dinormalpropylsulfuryl group Famoyl group, diisopropylsulfamo Group, di-n-butyl sulfamoyl group and the like.

  Examples of the substituent when the sulfamoyl group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxylic acid. Group, sulfonic acid group and heterocyclic group are preferred.

Among the above, the sulfamoyl group represented by R ¹ , R ² , R ³ or R ⁵ is preferably a sulfamoyl group having 1 to 20 carbon atoms, more preferably a sulfamoyl group having 1 to 15 carbon atoms, A famoyl group is particularly preferred.

The alkoxycarbonylamino group represented by R ¹ , R ² , R ³ and R ⁵ may be unsubstituted or substituted, and examples thereof include a methoxycarbonylamino group, an ethoxycarbonylamino group, and normal propyl. Oxycarbonylamino group, isopropyloxycarbonylamino group, normal butyloxycarbonylamino group, isobutyloxycarbonylamino group, tertiary butyloxycarbonylamino group, pentyloxycarbonylamino group, cyclopentyloxycarbonylamino group, hexyloxycarbonylamino group, Cyclohexyloxycarbonylamino group, heptyloxycarbonylamino group, octyloxycarbonylamino group, tertiary octyloxycarbonylamino group, 2-ethylhexylsulfoxycarbo Arylamino group and the like.

  Examples of the substituent when the alkoxycarbonylamino group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, Carboxylic acid groups, sulfonic acid groups, and heterocyclic groups are preferred.

Among the ^{above, R 1, R 2, R} 3, or The alkoxycarbonylamino group represented by R ^5, preferably an alkoxycarbonylamino group having 1 to 20 carbon atoms, an alkoxycarbonylamino group having 1 to 15 carbon atoms Are more preferable, and a methoxycarbonylamino group is particularly preferable.

The alkoxysulfonylamino group represented by R ¹ , R ² , R ³ , and R ⁵ may be unsubstituted or substituted, and examples thereof include a methoxysulfonylamino group, an ethoxysulfonylamino group, and normal propyl. Oxysulfonylamino group, isopropyloxysulfonylamino group, normal butyloxysulfonylamino group, isobutyloxysulfonylamino group, tertiary butyloxysulfonylamino group, pentyloxysulfonylamino group, cyclopentyloxysulfonylamino group, hexyloxysulfonylamino group, Cyclohexyloxysulfonylamino group, heptyloxysulfonylamino group, octyloxysulfonylamino group, tertiary octyloxysulfonylamino group, 2-ethylhexylsulfoxysulfo Arylamino group and the like.

  Examples of the substituent when the alkoxysulfonylamino group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, Carboxylic acid groups, sulfonic acid groups, and heterocyclic groups are preferred.

Among the above, the alkoxysulfonylamino group represented by R ¹ , R ² , R ³ , or R ⁵ is preferably an alkoxysulfonylamino group having 1 to 20 carbon atoms, and an alkoxysulfonylamino group having 1 to 15 carbon atoms. Are more preferable, and a methoxysulfonylamino group is particularly preferable.

The carbamoylamino group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, and examples thereof include a carbamoylamino group, a methylcarbamoylamino group, and an ethylcarbamoylamino group. , Normal propylcarbamoylamino group, isopropylcarbamoylamino group, normalbutylcarbamoylamino group, isobutylcarbamoylamino group, tertiary butylcarbamoylamino group, pentylcarbamoylamino group, cyclopentylcarbamoylamino group, hexylcarbamoylamino group, cyclohexylcarbamoylamino group , Heptylcarbamoylamino group, octylcarbamoylamino group, tertiary octylcarbamoylamino group, 2-ethylhexylcarbamoylamino group, dimethylcarbamoylamino group Diethylcarbamoyl amino group and the like.

  Examples of the substituent when the carbamoylamino group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxyl group. An acid group, a sulfonic acid group, and a heterocyclic group are preferable.

Among the above, the carbamoylamino group represented by R ¹ , R ² , R ³ or R ⁵ is preferably a carbamoylamino group having 1 to 20 carbon atoms, more preferably a carbamoylamino group having 1 to 15 carbon atoms. A methylcarbamoylamino group is particularly preferred.

The sulfamoylamino group represented by R ¹ , R ² , R ³ or R ⁵ may be unsubstituted or substituted, and examples thereof include a sulfamoylamino group and a methylsulfamoylamino group. Group, ethylsulfamoylamino group, normal propylsulfamoylamino group, isopropylsulfamoylamino group, normal butylsulfamoylamino group, isobutylsulfamoylamino group, tertiary butylsulfamoylamino group, pentylsulfur Famoylamino group, cyclopentylsulfamoylamino group, hexylsulfamoylamino group, cyclohexylsulfamoylamino group, heptylsulfamoylamino group, octylsulfamoylamino group, tertiary octylsulfamoylamino group, 2 -Ethylhexylsulfamoylami Group, dimethylsulfamoyl group, such as diethyl sulfamoylamino group preferably.

  Examples of the substituent when the sulfamoylamino group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, and a cyano group. , A carboxylic acid group, a sulfonic acid group, and a heterocyclic group are preferable.

Among the above, the sulfamoylamino group represented by R ¹ , R ² , R ³ , or R ⁵ is preferably a sulfamoylamino group having 1 to 20 carbon atoms, and a sulfamoyl group having 1 to 15 carbon atoms. An amino group is more preferred, and a methylsulfamoylamino group is particularly preferred.

The amino group represented by R ¹ , R ² , R ³ , or R ⁵ may be unsubstituted or substituted, and may be primary or secondary, such as an amino group, methyl Amino group, ethylamino group, normal propylamino group, isopropylamino group, normal butylamino group, isobutylamino group, tertiary butylamino group, pentylamino group, cyclopentylamino group, hexylamino group, cyclohexylamino group, heptylamino group Octylamino group, tertiary octylamino group, 2-ethylhexylamino group, dimethylamino group, diethylamino group, dinormalpropylamino group, diisopropylamino group, dinormalbutylamino group, phenylamino group, tolylamino group, etc. Can be mentioned.

  Examples of the substituent when the amino group further has a substituent include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, and a carboxylic acid. Group, sulfonic acid group and heterocyclic group are preferred.

Among the above, the amino group represented by R ¹ , R ² , R ³ , or R ⁵ is preferably an amino group having 1 to 20 carbon atoms, more preferably an amino group having 1 to 15 carbon atoms, and phenylamino Groups are particularly preferred.

Preferred examples of the halogen atom represented by R ¹ , R ² , R ³ , or R ⁵ include F, Cl, Br, and I. Particularly preferred is Cl.

Preferred examples of the heterocyclic group represented by R ¹ , R ² , or R ³ include groups such as a pyridine ring, an imidazole ring, a thiazole ring, an oxazole ring, and a pyrazole ring. A pyridine ring group is particularly preferable.

In the above, R ¹ and R ² , R ² and R ⁶ , R ⁵ and R ³ , R ⁶ and R ⁷ , R ² and R ⁸ , R ² and R ⁹ are connected to each other to form a ring. As the ring formed, for example, a cyclohexane ring, a benzene ring, a thiazole ring, a pyrrolidine ring, and a piperazine ring are suitable.

In the general formula (1), ring B, A ^- is a part which forms a salt along with a heterocyclic 5-membered ring. Ring B represents a saturated or unsaturated hetero 5-membered ring formed with a nitrogen atom, a carbon atom, and Z, and this hetero 5-membered ring may be condensed. Examples of the saturated hetero 5-membered ring include imidazolidinium salt, thiazolidinium salt, oxazolidinium salt, and the unsaturated hetero 5-membered ring includes imidazolium salt, thiazolium salt, oxazolium salt, triazolium salt, oxadiazo salt. Examples of the condensed ring include benzoimidazolium salt and benzothiazolium salt.
Among these, imidazolidinium salts, thiazolidinium salts, imidazolium salts, thiazolium salts, and oxazolium salts are more preferable, and imidazolidinium salts and imidazolium salts are particularly preferable. Furthermore, a saturated ring (saturated hetero 5-membered ring) is most preferable.

In the general formula (1), A ⁻ represents a counter anion. The counter anion represented by A ⁻ is not particularly limited as long as it can form a counter anion, and may be either a monoanion or a polyanion, and may be any of an inorganic anion and an organic anion. Good. Specifically, Cl ⁻ , Br ⁻ , I ⁻ , a sulfonate anion having 1 to 20 carbon atoms, a carboxylate anion having 2 to 21 carbon atoms, an alkyl sulfate ion, a hexafluorophosphate ion, a tetrafluoroboron ion, and perchlorine. Acid ions, carbonate ions and sulfate ions are preferable, and hexafluorophosphate ions are more preferable.

When R ⁴ has a substituent, the substituent may form a salt in place of the counter anion represented by A ⁻ , and in this case, the azo compound is constituted as an inner salt.

In the above, any one of (1) an aspect in which X is a nitrogen atom, (2) an aspect in which Y is NR ⁶ R ⁷ , and (3) an aspect in which Z is NR ¹⁰ (R ¹⁰ is particularly an aryl group) A compound that satisfies one is preferable, an aspect that satisfies any two or more of the above (1) to (3) is more preferable, and an aspect that satisfies all of the above (1) to (3) is still more preferable.
In particular, R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom, R ³ is a hydrogen atom, R ⁴ is a 2,4,6-trimethylphenyl group, 2,6 Preferred is a compound that is a diisopropylphenyl group, X is N, Y is NR ⁶ R ⁷ , and Z is NR ¹⁰ (R ¹⁰ is particularly an aryl group). Here, preferred embodiments of R ⁶ and R ⁷ and preferred embodiments of the aryl group of R ¹⁰ are as described above.

  The cationic azo compound is an oil-soluble compound. Here, “oil-soluble” means that the solubility in water at 25 ° C. (the mass of the pigment dissolved in 100 g of water) is 1 g or less, preferably the solubility is 0.5 g or less, more preferably 0.1 g or less. That is, in the present invention, so-called water-insoluble oil-soluble dyes are preferably used.

  Hereinafter, specific examples (Exemplary Compounds D-1 to D-136) of the cationic azo compound represented by the general formula (1) are listed. However, the present invention is not limited to these.

  Among the above cationic azo compounds, those having a high oxidation potential are desirable from the viewpoint of improving discoloration, resistance to oxidizing substances such as light and ozone (particularly light resistance) and curing characteristics. Specifically, it is preferable that the oxidation potential of the cationic azo compound is nobler than 1.0 V (vs SCE). Among them, a higher oxidation potential is preferable, an oxidation potential of 1.1 V to 2.0 V (vs SCE) is more preferable, and an oxidation potential of 1.15 V to 2.0 V (vs SCE) is particularly preferable.

  The oxidation potential value (Eox) can be easily measured by those skilled in the art. Regarding the measuring method, for example, P.I. Delahay, “New Instrumental Methods in Electrochemistry” (1954, published by Interscience Publishers); J. et al. "Electrochemical Methods" by Bard et al. (1980, published by John Wiley & Sons) and Akira Fujishima et al., "Electrochemical Measurement Methods" (1984, published by Gihodo Publishing Co., Ltd.).

Specifically, the oxidation potential is 1 × 10 ⁻² to 1 × 10 ^{−6 in} a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate. Dissolve in mol / liter and measure as a value for SCE (saturated calomel electrode) using various voltammetry (polarography using a dropping mercury electrode, cyclic voltammetry, method using a rotating disk electrode, etc.). This value may deviate by several tens of mil volts due to the effect of the liquid potential difference or the liquid resistance of the sample solution. However, it is possible to guarantee the reproducibility of the potential by inserting a standard sample (for example, hydroquinone or ferrocene). it can.
In the present invention, SCE (saturated calomel) is used as a reference electrode in N, N-dimethylformamide (concentration of dye is 0.001 mol / liter) containing 0.1 mol / liter of tetrapropylammonium perchlorate as a supporting electrolyte. Electrode), a value measured using a graphite electrode as a working electrode and a platinum electrode as a counter electrode (vs SCE) is defined as the oxidation potential of the dye.

  The value of Eox represents the ease of transfer of electrons from the sample to the electrode, and the greater the value (the higher the oxidation potential), the less transfer of electrons from the sample to the electrode, in other words, less oxidation. . In relation to the structure of the compound, the oxidation potential becomes more noble by introducing an electron withdrawing group, and the oxidation potential becomes lower by introducing an electron donating group. In the present invention, in order to lower the reactivity with ozone as an electrophile, it is desirable to introduce an electron withdrawing group into the dye skeleton to make the oxidation potential more noble.

Next, a method for synthesizing the cationic azo compound in the present invention will be described.
For the synthesis method of the cationic azo compound, see, for example, H.P. Zollinger, “Color Chemistry” 1991, Weinheim, p. 109 or the like can be referred to. Among them, a method of synthesizing an azo compound by reacting a diazonium salt compound and a coupler compound is versatile and useful, and can be suitably synthesized by reacting a corresponding diazonium salt compound and a coupler compound. is there.

  For example, the synthesis of the exemplified compound D-1 described above can be performed as shown in the following scheme. That is, 1.8 g of the following coupler (b) is dissolved in 50 ml of methanol, 3.0 g of diazonium salt (a) is added, and 1.0 g of sodium methoxide is further added thereto, followed by stirring at room temperature for 1 hour. To this reaction solution, 200 ml of water and 200 ml of ethyl acetate are added, and an extraction operation is performed. And after concentrating an organic layer, it refine | purifies by column chromatography and the exemplary compound D-1 which is a cationic azo compound of this invention is obtained.

Various solvents can be used for the above synthesis, and examples of the solvent include water, alcohol, ethyl acetate, ether, tetrahydrofuran (THF) and the like. Further, for the purpose of increasing the yield, an organic or inorganic base may coexist, and examples of these bases include sodium hydroxide, ammonia, triethylamine, pyridine, sodium bicarbonate, sodium methoxide and the like. The conditions for reacting the diazonium salt (a) with the coupler (b) are preferably added in the range of 1.0 to 1.1 equivalents of coupler with respect to 1 molar equivalent of the diazonium salt, and the reaction temperature is 0 ° C. to room temperature. It is preferable to make it react with. Further, since the diazonium salt is decomposed by light, it is preferable to use a light-shielding container as a reaction container or to react in a dark room.
The cationic azo compound other than the exemplified compound D-1 can also be synthesized by a method similar to the above.

  The content of the cationic azo compound in the ink composition is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, and still more preferably 5 to 15% by mass. When the content of the cationic azo compound is within the above range, the curability is good and high-speed curing is possible, and it is effective for forming an image excellent in light resistance.

(Polymerizable compound)
The ink composition of the present invention contains at least one polymerizable compound. The polymerizable compound is not particularly limited as long as it is a compound that causes a polymerization reaction by being imparted with some energy and cures, and can be used regardless of the type of monomer, oligomer, or polymer. In particular, various known polymerizable monomers known as cationic polymerizable monomers and radical polymerizable monomers that cause a polymerization reaction by the action of an initiation species generated from a polymerization initiator described later are preferable, and radical polymerizable monomers are particularly preferable. . When a radical polymerizable monomer is used, the effect of the cationic azo compound is more effectively exhibited.

  The polymerizable compound can be used alone or in combination of a plurality of types for the purpose of adjusting the reaction rate, ink physical properties, cured film physical properties and the like. The polymerizable compound may be a monofunctional compound or a polyfunctional compound.

  Examples of the cationic polymerizable monomer include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and 2001. Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like described in each publication such as No. 220526.

Examples of the epoxy compound include aromatic epoxides and alicyclic epoxides.
Among the epoxy compounds, 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, 1, 3-butadiene monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3-vinyl Examples include cyclohexene oxide.

  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) Til) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6 '-Methylcyclohexanecarboxylate,

Methylene bis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylene bis (3,4-epoxycyclohexanecarboxylate), dioctyl epoxy hexahydrophthalate , Epoxyhexahydrophthalic acid di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, Polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8-diepoxy Tan, 1,2,5,6-diepoxy cyclooctane, and the like.
Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable from the viewpoint of excellent curing speed, and alicyclic epoxides are particularly preferable.

  With respect to the vinyl ether compound, examples of the monofunctional vinyl ether 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, and 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, methoxy Liethylene 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 Chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether, and the like.

  Examples of the polyfunctional vinyl ether include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether. Divinyl ethers such as trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol Savinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide addition Examples thereof include polyfunctional vinyl ethers such as pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.

  As the vinyl ether compound, di- or trivinyl ether compounds are preferable from the viewpoints of curability, adhesion to a recording material, surface hardness of the formed image, and the like, and divinyl ether compounds are particularly preferable.

  The oxetane compound refers to a compound having an oxetane ring, and arbitrarily selected from known oxetane compounds described in JP-A Nos. 2001-220526, 2001-310937, 2003-341217, etc. Can be used.

  As the compound having an oxetane ring (oxetane compound), a compound having 1 to 4 oxetane rings in the structure is preferable. By selectively using such a compound, it is easy to maintain the viscosity of the ink composition in a good handling range, and to obtain high adhesion to the recording material of the ink after curing. Can do.

  Among the oxetane compounds, examples of monofunctional oxetane compounds include 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, and (3-ethyl-3-oxetanylmethoxy) methyl. Benzene, 4-fluoro- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, 4-methoxy- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, [1- (3- Ethyl-3-oxetanylmethoxy) 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-oxetanylmethyl) 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-tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3- Xetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether, Examples include 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, tri Ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3- Ru-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-ethyl-3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) Ether, caprolactone-modified dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropanetetrakis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis (3-ethyl-3-oxetanyl) Methyl) 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) include polyfunctional oxetanes such as ether.

  The compounds having such an oxetane ring are described in detail in paragraphs [0021] to [0084] of JP-A No. 2003-341217, and the compounds described herein can be suitably used in the present invention.

  Among the oxetane compounds, 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 compound may be used alone or in combination of two or more. From the viewpoint of effectively suppressing shrinkage during ink curing, It is preferable to use at least one oxetane compound in combination with at least one compound selected from an epoxy compound and a vinyl ether compound.

  In the present invention, it is particularly preferable to use a radically polymerizable monomer as the polymerizable compound, and it can be cured by causing a polymerization reaction by the action of the starting species generated from the polymerization initiator described later.

  Examples of the radical polymerizable monomer include (meth) acrylates, (meth) acrylamides, aromatic vinyls, and the like.

  In this specification, “(meth) acrylate” indicates that it can take both forms of “acrylate” and “methacrylate”, and “(meth) acryl” indicates both “acryl” and “methacryl”. It can take the form of

Examples of the (meth) acrylates include the following.
Specific examples of monofunctional (meth) acrylates include hexyl group (meth) acrylate, 2-ethylhexyl (meth) acrylate, tert-octyl (meth) acrylate, isoamyl (meth) acrylate, decyl (meth) acrylate, and 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 diglycol (meth) acrylate, butoxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 4-bromobutyl (meth) acrylate, cyanoeth (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, glycidyloxy Chill (meth) acrylate, glycidyloxyethyl (meth) acrylate, glycidyloxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyalkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3- Hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, dimethylaminoethyl (meth) acrylate , Diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, trimethoxysilylpropyl (meth) acrylate Rate,

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, poly Ethylene 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-methacrylic acid Leuoxyhexahydrophthalic acid, 2-methacryloyloxyethyl-2 Hydroxypropyl phthalate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, EO-modified phenol (meth) acrylate, EO Examples thereof include modified cresol (meth) acrylate, EO-modified nonylphenol (meth) acrylate, PO-modified nonylphenol (meth) acrylate, and EO-modified-2-ethylhexyl (meth) acrylate.

  Specific 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) acrylate 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 ( Examples include meth) acrylate, 1,9-nonanedi (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, and tricyclodecane di (meth) acrylate.

  Specific examples of trifunctional (meth) acrylates include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane alkylene oxide modified tri (meth) acrylate, pentaerythritol tri (meth) acrylate , Dipentaerythritol tri (meth) acrylate, trimethylolpropane tri ((meth) acryloyloxypropyl) ether, isocyanuric acid alkylene oxide modified tri (meth) acrylate, propionate dipentaerythritol tri (meth) acrylate, tri ((meta ) Acryloyloxyethyl) isocyanurate, hydroxypivalaldehyde modified dimethylolpropane tri (meth) acrylate, sorbitol tri (meth) acrylate Rate, propoxylated trimethylolpropane tri (meth) acrylate, and ethoxylated glycerin triacrylate.

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

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

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

  Examples of (meth) acrylamides that are radical polymerizable monomers include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, and Nn-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 and (meth) acryloylmorpholine are mentioned.

  Examples of aromatic vinyls include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoate. 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, isopropenylstyrene, butenylstyrene, octyl Nirusuchiren, 4-t-butoxycarbonyl styrene, 4-methoxystyrene, and a 4-t-butoxystyrene.

  In addition to the radical polymerizable monomers other than the above, 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, etc.], vinyl cyanide [(meth) acrylonitrile, etc.], olefins [ethylene, propylene, etc. ] Etc. are mentioned.

  In the present invention, as the radical polymerizable monomer, (meth) acrylates and (meth) acrylamides are preferable from the viewpoint of curing speed, and tetrafunctional or higher (meth) acrylate is particularly preferable from the viewpoint of curing speed. Furthermore, from the viewpoint of the viscosity of the ink composition, the polyfunctional (meth) acrylate and the monofunctional or bifunctional (meth) acrylate and / or (meth) acrylamide are 1: 9 to 9: 1 (mass ratio). It is preferable to use together.

  The content of the polymerizable compound in the ink composition is appropriately 50 to 95% by mass, preferably 60 to 92% by mass, more preferably 70 to 90% by mass, based on the total solid content of the composition. Range.

(Polymerization initiator)
The ink composition of the present invention contains at least one polymerization initiator. The polymerization initiator undergoes a chemical change through the action of light, interaction with the electronically excited state of the sensitizing dye, or the action of heat, and at least one of active species (polymerization initiating species) of radicals, acids, and bases. A compound that produces a seed. Among these, in the ink composition of the present invention, a photopolymerization initiator that generates active species through the action of light is preferable, and a photopolymerization initiator that promotes radical polymerization or cationic polymerization reaction is preferable.

  The photopolymerization initiator is an actinic ray to be irradiated, for example, 200 to 400 nm ultraviolet rays, far ultraviolet rays, g rays, h rays, i rays, KrF excimer laser rays, ArF excimer laser rays, electron rays, X rays, molecular rays. Or what has a sensitivity to an ion beam etc. can be selected suitably, and can be used.

  As the photopolymerization initiator, those known to those skilled in the art can be used without limitation, and specifically, for example, 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 mentioned. In addition, compounds that are used in chemically amplified photoresists and photocationic polymerization described in “Organic Materials for Imaging” (see Organic Electronics Materials Study Group, Bunshin Publishing (1993), p. 187 to 192) Can be mentioned. Further, F.R. D. Saeva, Topics in Current Chemistry, 156, 59 (1990); G. Maslak, Topics in Current Chemistry, 168, 1 (1993); B. Shuster et al, JACS, 112, 6329 (1990); D. F. A group of compounds that undergo oxidative or reductive bond cleavage through interaction with the electronically excited state of a sensitizing dye as described in Eaton et al, JACS, 102, 3298 (1980), etc. is also known.

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

  As a preferable example of the (a) aromatic ketones, a benzophenone skeleton described in “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” (JP POUASSISER JF RABEK (1993), p. 77 to 117). Or the compound etc. which have a thioxanthone skeleton are mentioned.

  More preferable examples of (a) aromatic ketones include α-thiobenzophenone compounds described in JP-B-47-6416, benzoin ether compounds described in JP-B-47-3981, and JP-B-47-22326. Α-substituted benzoin compounds described in JP-A No. 47-23664, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, and JP-B-60-26483 Dialkoxybenzophenone, benzoin ethers described in JP-B-60-26403, JP-A-62-81345, JP-B-1-34242, US Pat. No. 4,318,791, European Patent 0284561A1 Α-aminobenzophenones described in JP-A-2-21152. P-di (dimethylaminobenzoyl) benzene, a thio-substituted aromatic ketone described in JP-A-61-194062, an acylphosphine sulfide described in JP-B-2-9597, and JP-B-2-9596 Examples thereof include acylphosphine described above, thioxanthones described in JP-B-63-61950, and coumarins described in JP-B-59-42864.

  Examples of the (b) aromatic onium salt compound include elements of Group V, Group VI, and Group VII of the Periodic Table, specifically, N, P, As, Sb, Bi, O, S, Se. , Te, or I aromatic onium salts. For example, European Patent No. 104143, US Pat. No. 4,837,124, Japanese Patent Laid-Open No. 2-150848, Japanese Patent Laid-Open No. 2-96514, iodonium salts, European Patent Nos. 370693, 233567, 297443, The sulfonium salts and diazonium salts described in the specifications of U.S. Pat. Nos. 297442, 279210, and 422570, U.S. Pat. Nos. 3,902,144, 4,933,377, 4,760013, 4,734,444, and 2,833,827 (Such as benzenediazonium which may have a substituent), diazonium salt resins (formaldehyde resin of diazodiphenylamine, etc.), N-alkoxypyridinium salts, etc. (for example, US Pat. No. 4,743,528, JP 63-138345, JP-A 63-142345, JP-A 63-142346, and JP-B 46-42363, specifically 1-methoxy-4-phenylpyridinium tetrafluoroborate, etc.) The compounds described in JP-B Nos. 52-147277, 52-14278, and 52-14279 are preferable. Active species are those that generate radicals and acids.

  The organic peroxide (c) includes almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. Among them, for example, 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- ( Peroxyesters such as (cumylperoxycarbonyl) benzophenone, 3,3'4,4'-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, di-t-butyldiperoxyisophthalate are preferred.

  Examples of the (d) hexaarylbiimidazole compound include lophine dimers described in JP-B-45-37377 and JP-B-44-86516, such as 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) bi Imidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', , 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.

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

  Examples of the (f) borate compound include compounds described in US Pat. Nos. 3,567,453, 4,343,891, European Patents 109,772, 109,773, and the like. Can be mentioned.

  Examples of the (g) azinium salt compound include JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, and JP-B-46-42363. The compound group which has a NO bond as described in each gazette of No. can be mentioned.

  Examples of the (h) metallocene compound include, for example, JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, and JP-A-2-4705. Examples thereof include titanocene compounds described in the publication and iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109.

  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 active ester compound (i) include, for example, the specifications of European Patent Nos. 0290750, 046083, 156153, 271851, and 0388343, U.S. Pat. Nos. 3,901,710, and 4,181,531. Nitrobenzester compounds, European Patent Nos. 0199672, 84515, 199672, 0441115, and 0101122 described in JP-A-60-198538 and JP-A-53-133022. No. 4,618,564, U.S. Pat. No. 4,371,605 and U.S. Pat. No. 4,431,774, and JP-A 64-18143, JP-A 2-245756, and JP-A 4-365050. Iminosulfonate compounds, Shoko 62-6223, Shoko No. 63-14340, and compounds described in JP-A No. 59-174831, and the like.

  Preferred examples of the compound (j) having a carbon halogen bond include Wakabayashi et al., Bull. Chem. Soc. Japan, 42, 2924 (1969), a compound described in British Patent No. 1388492, a compound described in JP-A-53-133428, a compound described in German Patent No. 3337024, etc. Can be mentioned.

  F.F. C. J. Schaefer et al. Org. Chem. 29, 1527 (1964), a compound described in JP-A-62-58241, a compound described in JP-A-5-281728, a compound described in German Patent No. 2641100, a German patent The compound described in No. 3333450, the compound group described in German Patent No. 3021590, the compound group described in German Patent No. 3021599, etc. can be mentioned.

Hereinafter, preferable specific examples of the photopolymerization initiators (a) to (j) are listed.

A polymerization initiator can be used in combination of 2 or more types, in addition to being used alone.
The content of the photopolymerization initiator in the ink composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably in terms of the total solid content of the ink composition. Is 1-7 mass%.

(Other)
-Sensitizing dye-
In the present invention, a sensitizing dye may be added for the purpose of improving the sensitivity of the polymerization initiator. Examples of preferable sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in a wavelength region of 350 nm to 450 nm.

  Polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thiacarbocyanine, oxacarbocyanine), merocyanines (Eg, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, anthraquinone), squalium (eg, squalium) , Coumarins (eg 7-diethylamino-4-methylcoumarin).

  Examples of more preferable sensitizing dyes are compounds represented by the following general formulas (vi) to (x).

In the formula (vi), A ¹ represents a sulfur atom or NR ⁵⁰ , and R ⁵⁰ represents an alkyl group or an aryl group. L ¹ represents a nonmetallic atomic group that forms a basic nucleus of a dye together with adjacent A ¹ and a carbon atom. 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 formula (vii), Ar ¹ and Ar ² each independently represent an aryl group, and are linked via a bond with —L ² —. L ² represents —O— or —S—. Moreover, W is synonymous with W in the said general formula (vi).

In the formula (viii), A ² represents a sulfur atom or NR ⁵⁹ , L ³ represents a nonmetallic atomic group that forms a basic nucleus of the dye together with adjacent A ² and a carbon atom, and R ⁵³ , R ⁵⁴ , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ , and R ⁵⁸ each independently represents a monovalent nonmetallic atomic group, and R ⁵⁹ represents an alkyl group or an aryl group.

In the formula (ix), A ³ and A ⁴ each independently represent —S—, —NR ⁶² —, or —NR ⁶³ —, wherein R ⁶² and R ⁶³ each independently represent a substituted or unsubstituted alkyl group. Or a substituted or unsubstituted aryl group. L ⁴ and L ⁵ each represents a nonmetallic atomic group that forms a basic nucleus of a dye together with adjacent A ³ or A ⁴ and a carbon atom. R ⁶⁰ and R ⁶¹ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁶⁰ and R ⁶¹ may be bonded to each other to form an aliphatic or aromatic ring. .

In the formula (x), R ⁶⁶ represents an aromatic ring or a hetero ring which may have a substituent, and 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, and R ⁶⁷ and R ⁶⁴ , and R ⁶⁵ and R ⁶⁷ are bonded to each other to form an aliphatic group or An aromatic ring may be formed.

  Preferred specific examples of the compounds represented by the general formulas (vi) to (x) include the following exemplified compounds (A-1) to (A-20).

-Co-sensitizer-
In the ink composition of the present invention, a known compound having an action such as further improving sensitivity or suppressing polymerization inhibition by oxygen may be added as a co-sensitizer.
Examples of co-sensitizers include amines such as M.I. R. Sander et al., “Journal of Polymer Society”, Vol. 10, page 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, Japanese Patent Publication No. 59- Examples thereof include compounds described in JP-A No. 138205, JP-A-60-84305, JP-A-62-18537, JP-A-64-33104, and Research Disclosure 33825. Specific examples include triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

  Other examples of co-sensitizers include thiols and sulfides, for example, thiol compounds described in JP-A-53-702, JP-B-55-500806, and JP-A-5-142277, Examples thereof include disulfide compounds described in JP-A-56-75643. Specifically, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercaptonaphthalene and the like.

  Other examples include amino acid compounds (eg, N-phenylglycine, etc.), organometallic compounds described in JP-B-48-42965 (eg, tributyltin acetate), and JP-B-55-34414. The hydrogen donor described in JP-A-6-308727, sulfur compounds (eg, trithiane, etc.), JP-A-6-250387, phosphorus compounds (diethylphosphite, etc.), Japanese Patent Application No. 6-191605 Si-H, Ge-H compounds, etc. described in No.

  In the ink composition of the present invention, a solvent may be added as a dispersion medium for various components such as a coloring matter, and a constitution using no polymerizable solvent and the above-described polymerizable compound as a low molecular weight component as a dispersion medium. It is good. The ink composition of the present invention is a radiation curable ink, and is preferably composed of a solvent-free ink since the ink is applied onto a recording material and then cured. This is because if the solvent remains in the cured ink image, the solvent resistance is deteriorated or a problem of VOC (Volatile Organic Compound) of the remaining solvent occurs. From such a viewpoint, it is preferable to select a polymerizable compound, particularly a radically polymerizable monomer having the lowest viscosity, as a dispersion medium from the viewpoint of improving dispersibility and handling properties of the ink composition.

In the ink composition of the present invention, various additives can be used in combination with the above-described components as required for the purpose and the like.
Specifically, an ultraviolet absorber can be added from the viewpoint of improving the weather resistance of the formed image and preventing fading, and an antioxidant may be added to improve the stability of the ink composition. it can. Furthermore, various organic and metal complex anti-fading agents, and conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride, and recording materials from the viewpoint of controlling ejection properties. From the viewpoint of improving adhesion, an extremely small amount of an organic solvent can be added. Various polymer compounds can be added from the viewpoint of adjusting film physical properties. As the polymer compound here, 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, Acrylic resins, rubber resins, waxes, and other natural resins can be used. Two or more of these may be used in combination. Moreover, a nonionic surfactant, an organic fluoro compound, etc. can also be added from a viewpoint of liquid physical property adjustment. In addition to the above, for example, leveling additives, matting agents, waxes for adjusting film properties, tackifiers that do not inhibit polymerization in order to improve the adhesion to recording materials such as polyolefin and PET, etc. Can do.

The ink composition of the present invention preferably has an ink viscosity of 50 mPa · s or less, more preferably 30 mPa · s or less, at the temperature at the time of injection, in consideration of ejection properties in the case of ink jet recording. By adjusting the composition ratio, the above range can be obtained.
The ink viscosity at 25 ° C. to 30 ° C. is preferably 10 to 200 mPa · s, more preferably 10 to 100 mPa · s. By setting the viscosity at room temperature high, even when a porous recording material is used, ink penetration into the recording material can be prevented, uncured monomers can be reduced after curing, and odor can be reduced. Dot bleeding at the time of landing of ink droplets can be suppressed, and as a result, image quality is improved. When the ink viscosity at 25 to 30 ° C. is within the above range, the effect of preventing bleeding is great, and the delivery property of the ink liquid is not impaired.

  In the ink composition of the present invention, the surface tension is from 20 to 30 mN / in terms of bleeding and penetration when recording on various recording materials such as polyolefin, polyethylene terephthalate (PET), coated paper, and uncoated paper. m is preferable, and more preferably 23 to 28 mN / m.

  The ink composition of the present invention is suitable for use as an ink for inkjet recording. In this case, the ink composition is loaded into, for example, an ink jet printer, applied to a recording material from an ink jet head, image recorded, and the recorded image is irradiated with active energy rays such as ultraviolet rays and cured to perform recording. be able to.

  In the recorded matter obtained using the ink composition of the present invention, the image portion made of the ink composition is cured by irradiation with active energy rays, and the strength and light resistance of the image portion are excellent. For example, it can be applied to various uses such as formation of an ink receiving layer (image part) of a lithographic printing plate.

The image forming method of the present invention is a method using the above-described ink composition of the present invention.
The image forming method of the first aspect of the invention is characterized in that an image is recorded on a recording material by using the ink composition of the invention of the invention described above, and the second image forming method is a recording method. Regardless of form, the image using the ink composition of the present invention described above is cured by irradiation with active energy rays. Also,
The image forming method of the third aspect of the present invention includes a recording step of recording an image on a recording material using the ink composition of the present invention described above, and curing for irradiating the recorded image with an active energy ray and curing it. And the recording step is preferably in the form of inkjet recording of an image by discharging the ink composition.

  The recording (including the case of the recording process in the third invention) is more suitable for ink jet recording in which, for example, an ink jet printer is used and the ink composition of the present invention is discharged from the ink jet head to record an image on a recording material. An image can be formed. In the third invention, image recording may be performed by a method other than inkjet recording, for example, any method capable of applying the ink composition of the present invention onto a recording material such as coating.

  When ink jet recording is performed, the ink composition is heated to 40 to 80 ° C., and the viscosity is reduced to 50 mPa · s or less, preferably 30 mPa · s or less to achieve high injection stability. Is preferable. In general, radiation curable ink compositions generally have a higher viscosity than aqueous inks, and therefore have a large viscosity fluctuation range due to temperature fluctuations during recording. Viscosity fluctuations in the ink composition greatly affect the droplet size and droplet ejection speed as they are, and are liable to cause image quality deterioration. Therefore, it is important to keep the temperature of the ink composition during recording as constant as possible. The temperature control width of the ink composition is preferably set temperature ± 5 ° C, more preferably set temperature ± 2 ° C, and still more preferably set temperature ± 1 ° C.

The ink jet recording apparatus is preferably provided with a stabilizing means for keeping the temperature of the ink composition at a predetermined temperature, and the portion for keeping the ink composition at a constant temperature is an ink tank (if there is an intermediate tank, an intermediate tank) To all of the piping system and members from the nozzle injection surface. The temperature control method is not particularly limited, but for example, it is preferable that a plurality of temperature sensors are provided in each piping portion so that heating control according to the flow rate of the ink composition and the environmental temperature is possible. . The head unit that discharges the ink composition is preferably thermally shielded or insulated so that the apparatus main body is not affected by the temperature of the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of thermal energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.
In the present invention, inkjet recording can be performed using a commercially available inkjet recording apparatus as the inkjet recording apparatus.

  Curing (including the case of the curing step in the third invention) is performed by irradiation with active energy rays. Irradiation can basically be performed by the method described in JP-A-60-132767. Specifically, a light source is provided on both sides of the head unit, and the head and the light source are scanned by a shuttle method. It is preferable that the irradiation is performed after a certain period of time after the ink has landed on the recording material. . Furthermore, the curing can be completed by another light source that is not driven. It is also possible to use a method described in WO99 / 54415 using an optical fiber, or a method of irradiating a recording unit with UV light by applying a collimated light source to a mirror surface provided on the side of the head unit.

  In addition, while heating the ink composition to a constant temperature, it is desirable that the time from the landing of the ink to the irradiation of the active energy ray is 0.01 to 0.5 seconds, preferably 0.01 to 0.3. Seconds, more preferably 0.01 to 0.15 seconds. Controlling the time from landing to irradiation within the above-mentioned range, that is, in a short time, can effectively prevent the landing ink from spreading before curing, and the deep part where the light source does not reach even for porous recording materials Since it is possible to irradiate with light before the ink composition penetrates, residual unreacted monomer after curing is suppressed, which is effective in reducing odor.

  When performing ink jet recording as described above, a great synergistic effect can be obtained by combining the ink compositions of the present invention. In particular, when an ink composition having an ink viscosity of 10 to 200 mPa · s at 25 ° C. is used, the dot diameter of ink landed on various recording materials having different surface wettability can be kept constant. It is possible and the image quality can be improved. In addition, in order to obtain a color image, it is preferable to superimpose in order from the color with the lowest brightness. When inks with low lightness are stacked, it is difficult for the irradiation line to reach the lower ink, and the curing sensitivity is hindered, the residual monomer is increased, odor is generated, and the adhesion is liable to occur. Irradiation can be performed by injecting all colors and exposing them together, but exposure for each color is preferable from the viewpoint of promoting curing.

(Recording material)
The recording material is not particularly limited, and papers such as ordinary uncoated paper and coated paper, various non-absorbent resin materials used for so-called soft packaging, or resin films obtained by forming the film into a film shape are used. be able to. Examples of the resin film include a PET film, an OPS film, an OPP film, an ONy film, a PVC film, a PE film, and a TAC film. Furthermore, polycarbonate, acrylic resin, ABS, polyacetal, PVA, rubber and other plastic materials, metals, and glasses can also be used as the recording material.

  By using the ink composition of the present invention to perform ink jet recording or curing using, for example, an ink jet printer, or by using the ink composition of the present invention to perform ink jet recording on a recording material using, for example, an ink jet printer, a recorded image (ink The recorded material of the present invention can be obtained by irradiating the composition with active energy rays and curing. The recorded matter of the present invention can be applied to a wide range of fields because a high-quality image excellent in color development and sharpness is provided with high hardness and the weather resistance (particularly light resistance) of the image is excellent. It is.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof. Unless otherwise specified, “part” is based on mass.

(Example 1): radical polymerization system Under a yellow light, as a polymerizable compound, 3 g of 1,6-hexanediol diacrylate (HDDA; manufactured by Daicel UCB) and dipentaerythritol hexaacrylate (DPHA; manufactured by Nippon Kayaku Co., Ltd.) ) 7 g was mixed, and 0.3 g of Irgacure 1870 (manufactured by Ciba Specialty Chemicals) was added thereto as a polymerization initiator, and then the following dye D-73 (represented by the general formula (1) described above) Example compounds of cationic azo compound) 0.1 g was added, stirred and dissolved to prepare an ink composition containing the cationic azo compound.

The ink composition obtained above was printed on an OHP sheet using an inkjet printer PM-G800 (printing density 300 dpi, droplet ejection frequency 4 kHz, nozzle number 64; manufactured by Seiko Epson Corporation) to form a color image, and then Deep A cured print sample was obtained by exposure under an energy condition of 15 mJ / cm ^{2 with} a UV lamp SP-7 (USHIO).

(Example 2): Cationic polymerization system Under a yellow light, 7 g of OXT-221 (manufactured by Toagosei Co., Ltd.) and 3 g of celoxide 2021 (manufactured by Daicel Chemical Industries, Ltd.) are mixed as a polymerizable compound, and this is used as a polymerization initiator. Then, 0.3 g of UVI-6992 (manufactured by Dow Chemical Company) was added, and then the above-mentioned dye D-73 (an exemplary compound of the cationic azo compound represented by the general formula (1) described above) was further added to the amount of 0. 1 g was added, stirred and dissolved to obtain an ink composition containing a cationic azo compound.

Using the obtained ink composition, printing was performed in the same manner as in Example 1 to form a color image, which was then exposed and cured under an energy condition of 45 mJ / cm ² with a Deep UV lamp SP-7 (manufactured by Ushio). A printed sample was obtained.

(Example 3): Radical polymerization system In Example 1, except that the dye D-73 was replaced with the following dye D-49 (an exemplary compound of a cationic azo compound represented by the general formula (1) described above) In the same manner as in Example 1, a cured print sample was obtained.

(Example 4): Cationic polymerization system In Example 2, except that the dye D-73 was replaced with the dye D-49 (an exemplary compound of the cationic azo compound represented by the general formula (1) described above). In the same manner as in Example 2, a cured print sample was obtained.

(Example 5): Radical polymerization system In Example 1, except that the dye D-73 was replaced with the following dye D-110 (an exemplary compound of the cationic azo compound represented by the general formula (1) described above). In the same manner as in Example 1, a cured print sample was obtained.

(Example 6): Cationic polymerization system In Example 2, except that the dye D-73 was replaced with the dye D-110 (an exemplary compound of the cationic azo compound represented by the general formula (1) described above). In the same manner as in Example 2, a cured print sample was obtained.

(Example 7): Radical polymerization system In Example 1, except that the dye D-73 was replaced with the following dye D-92 (an exemplary compound of the cationic azo compound represented by the general formula (1) described above). In the same manner as in Example 1, a cured print sample was obtained.

(Example 8): Cationic polymerization system In Example 2, except that the dye D-73 was replaced with the dye D-92 (an exemplary compound of the cationic azo compound represented by the general formula (1) described above). In the same manner as in Example 2, a cured print sample was obtained.

(Example 9): Radical polymerization system In Example 1, except that the dye D-73 was replaced with the following dye D-57 (an exemplary compound of the cationic azo compound represented by the general formula (1) described above). In the same manner as in Example 1, a cured print sample was obtained.

(Example 10): Cationic polymerization system In Example 2, except that the dye D-73 was replaced with the dye D-57 (an exemplary compound of the cationic azo compound represented by the general formula (1) described above). In the same manner as in Example 2, a cured print sample was obtained.

(Comparative Example 1)
A cured comparative print sample was obtained in the same manner as in Example 1 except that the dye D-73 was replaced with the following comparative dye R-1 in Example 1.

(Comparative Example 2)
In Example 2, a cured comparative print sample was obtained in the same manner as in Example 2, except that the dye D-73 was replaced with the comparative dye R-1.

(Evaluation)
The following evaluation was performed on the print samples of each Example and each Comparative Example. The evaluation results are shown in Table 1 below.
-1. Light resistance
For each of the obtained print samples, the density D ¹ of the unexposed color image was measured using a reflection densitometer X-Rite 310TR (manufactured by Nihon Hakusho Kaisha Co., Ltd.), and each print sample was measured with a weather meter (Atlas). C.165) is irradiated with xenon light (100,000 lux) for 3 days, the density D ² after irradiation in the color image is measured in the same manner as described above, and the residual ratio of dye (%; D; before and after irradiation with xenon light) ² / D ¹ × 100) and used as an index for evaluating light resistance.

-2. Curability-
The surface of the color image of the printed sample was evaluated by the following tack-free test. That is, the surface of the color image, which is a cured film immediately after irradiation after printing, was touched with a finger and evaluated as A when there was no stickiness, as B when slightly sticky, and as C when markedly sticky. The smaller the stickiness, the better the curing speed and the better the curability, and only A is a practically acceptable evaluation.

  As shown in Table 1, the ink compositions of the examples were curable at high speed and excellent in curability, and the formed color image was excellent in light resistance. On the other hand, the ink composition of the comparative example was not only low in curing speed but also insufficient in the degree of curing, and inferior in light resistance of the formed image.

  In addition to the cationic azo compounds used in the above examples, the exemplary compounds of the cationic azo compounds described above also have cations at the same position in structure, and the exemplary compounds used above (cationic azo compounds) ), It is possible to form a color image that is curable at high speed and excellent in curability and excellent in light resistance as described above.

Claims (18)

  An ink composition comprising a cationic azo compound, a polymerizable compound, and a polymerization initiator. The ink composition according to claim 1, wherein the cationic azo compound is a compound represented by the following general formula (1).

[Wherein, R ¹ , R ² and R ³ each independently represents a hydrogen atom or a substituent. R ⁴ represents a hydrogen atom, an alkyl group, or an aryl group. X represents CR ⁵ or a nitrogen atom, Y represents NR ⁶ R ⁷ , SR ⁸ , or OR ⁹ , and Z represents an oxygen atom, a sulfur atom, or NR ¹⁰ . R ⁵ represents a hydrogen atom or a substituent. R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom, an alkyl group or an aryl group. Ring B represents a saturated or unsaturated hetero 5-membered ring together with a nitrogen atom, a carbon atom, and Z, and the hetero 5-membered ring may be condensed. A ⁻ represents a counter anion, and A ⁻ and R ^{1 to} R ¹⁰ may be linked to each other. R ¹ and R ² , R ² and R ⁶ , R ⁵ and R ³ , R ⁶ and R ⁷ , R ² and R ⁸ , R ² and R ⁹ may be connected to each other to form a ring. ] The substituent represented by R ¹ , R ² , or R ³ is an alkyl group, aryl group, alkoxy group, aryloxy group, alkylsulfonyl group, arylsulfonyl group, alkylthio group, arylthio group, cyano group, or acyl group. , Carbamoyl group, sulfamoyl group, amino group, alkoxycarbonylamino group, alkoxysulfonylamino group, carbamoylamino group, sulfamoylamino group, hydroxyl group, carboxylic acid group, sulfonic acid group, nitro group, halogen atom, or heterocyclic group The ink composition according to claim 2, wherein The substituent represented by R ⁵ is an alkyl group, aryl group, alkoxy group, aryloxy group, alkylsulfonyl group, arylsulfonyl group, alkylthio group, arylthio group, cyano group, acyl group, carbamoyl group, sulfamoyl group, The ink according to claim 2 or 3, which is an amino group, an alkoxycarbonylamino group, an alkoxysulfonylamino group, a carbamoylamino group, a sulfamoylamino group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, a nitro group, or a halogen atom. Composition. In the above general formula (1), Y is an ink composition according to any one of claims 2 to 4 is NR ⁶ R ^7. In Formula (1), the ink composition according to any one of claims 2 to 5 Z is NR ^10. The ink composition according to claim 6, wherein R ¹⁰ is an aryl group.   In the said General formula (1), X is a nitrogen atom, The ink composition of any one of Claims 2-7.   The ink composition according to any one of claims 2 to 8, wherein, in the general formula (1), ring B is a saturated complex 5-membered ring.   The ink composition according to any one of claims 1 to 9, wherein the cationic azo compound has an oxidation potential nobler than 1.0 V (vs SCE).   The ink composition according to claim 1, wherein the polymerizable compound is a radical polymerizable monomer.   The ink composition according to claim 1, wherein the polymerization initiator is a photopolymerization initiator.   The ink composition according to claim 1, which is used for inkjet recording.   An image forming method comprising: performing ink jet recording of an image on a recording material using the ink composition according to claim 1.   An image forming method comprising curing an image formed by using the ink composition according to claim 1 by irradiation with active energy rays.   A recording process for recording an image on a recording material using the ink composition according to claim 1, and a curing process for irradiating the recorded image with an active energy ray to cure the recorded image. An image forming method.   The image forming method according to claim 16, wherein in the recording step, the image is inkjet-recorded by discharging the ink composition.   A recorded matter comprising the ink composition according to claim 1.