JP2007091950A - Ink composition, image-forming method and recorded matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image-forming method enabling formation of solid image having high adhesiveness to substrates to be recorded and hardly peeled and to provide a recorded matter using the ink composition. <P>SOLUTION: The ink composition comprises a polymerizable compound (x) and a polymerizable compound (y) containing a silicon atom, wherein the mass ratio [(y)/(x+y)×100] of the compound (x) to the compound (y) is 1-20% and the polymerizable compound (y) containing a silicon atom is a (meth)acrylate-based compound having a siloxane bond. The image-forming method comprises using the ink composition. The recorded matter is obtained by using the ink composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink composition and an image forming method using the ink composition, and more specifically, an ink composition which can be cured by polymerization after recording and is suitable for robust image recording, and an image forming method and recording using the ink composition. Related to things.

  As an ink having fading resistance and the like, a UV ink that is cured by irradiation with ultraviolet rays (UV) and has a UV light shielding property is known (for example, see Patent Document 1).

  Curing using such an ink is widely used in systems utilizing a radical polymerization system of monomer components, and acrylate monomers are generally used as monomer components (see, for example, Patent Documents 2 to 4). .)

  As described above, in the case of using a curable ink that is irradiated with light such as UV light and cured after recording, the image itself is recorded by recording an image on the recording material and further polymerizing and curing the recorded image. It is possible to improve the robustness.

However, in such a curable ink that is cured by irradiation with light such as UV light, when an image recorded on a substrate as a recording material is polymerized and cured, the composition of the ink and the recording material Depending on the material (for example, a paper medium with a smooth recording surface, a resin such as PET, metal, glass, etc.) or the like, sufficient adhesion to the substrate may not be obtained. In such a case, for example, when a force is applied to the image such as bending the substrate on which the image is formed or scratching the formed image, the image is peeled relatively easily and the image is broken. In addition, when an additive is added to improve the adhesion, other performance such as light resistance may be impaired.
JP 2003-221528 A JP 2003-246818 A JP 2003-292855 A Japanese Patent Laid-Open No. 9-183927

  As described above, when the adhesion between the image and the recording medium (for example, metal, resin such as PET, glass, etc.) is not sufficiently obtained, the degree of curing of the image itself by polymerization curing, in other words, Although weather resistance against light, ozone, etc. can be ensured, it is inferior in peeling resistance, which is difficult to peel off from the recording material, so that the ink forming the image is peeled off and the image cannot be held stably for a long period of time. Value is greatly impaired.

  The present invention has been made in view of the above, and an ink composition that can form a robust image that has high adhesion to a recording material and is difficult to peel from the recording material, and the ink composition are used. Another object of the present invention is to provide an image forming method capable of forming a robust image that is hardly peeled off from a recording material and a recorded matter using the ink composition, and to achieve the object.

  Specific means for achieving the above object are as follows.

  <1> An ink composition comprising a polymerizable compound and a polymerizable compound containing a silicon atom.

  <2> The mass ratio (y / (x + y) × 100) of the polymerizable compound (x) and the polymerizable compound (y) containing a silicon atom is 1 to 20%. 1> ink composition.

  <3> The ink composition according to <1> or <2>, wherein the polymerizable compound containing a silicon atom is a (meth) acrylate compound having a siloxane bond.

（一般式（I）において、Ｒ¹は、水素原子又はメチル基を表し、Ｒ²は炭素数１〜５のアルキレン基を表す。Ｒ³は、−Ｏ−Ｒ⁴又はメチル基を表す。Ｒ⁴は、メチル基又はエチル基を表す。） <4> The ink composition according to <1> to <3>, wherein the polymerizable compound containing a silicon atom is a compound represented by the following general formula (I).

(In General Formula (I), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 1 to 5 carbon atoms. R ³ represents —O—R ⁴ or a methyl group. R ⁴ represents a methyl group or an ethyl group.)

  <5> The ink composition according to <1> to <4>, further including a polymerization initiator.

  <6> The ink composition according to <1> to <5>, wherein the ink composition includes a pigment or an oil-soluble dye as a colorant.

  <7> The ink composition according to <6>, wherein the colorant is an oil-soluble dye.

  <8> The ink composition according to <6> or <7>, wherein the dye has an oxidation potential nobler than 1.0 V (vs SCE).

  <9> The ink composition according to <1> to <8>, wherein the ink composition is used for ink jet recording.

  <10> An image forming method comprising an image recording step of recording an image on a recording material by inkjet recording in which the ink composition of <1> to <9> is discharged.

  <11> An image recording step of recording an image on a recording material using the ink composition of <1> to <9>, and an active energy ray on the image recorded on the recording material in the image recording step And an image curing step of irradiating and curing.

  <12> The image forming method according to <11>, wherein the image recording step records the image by inkjet recording in which the ink composition is discharged.

  <13> A recorded matter recorded using the ink composition according to <1> to <9>.

  According to the present invention, an ink composition having high adhesion to a recording material and capable of forming a robust image that is difficult to peel from the recording material, and the ink composition are used, and are not easily peeled off from the recording material. It is possible to provide an image forming method capable of forming a robust image and a recorded matter using the ink composition.

  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.

<Ink composition>
The ink composition of the present invention contains a polymerizable compound containing a silicon atom (hereinafter sometimes referred to as “silicon atom-containing polymerizable compound”) and a polymerizable compound other than the silicon atom-containing polymerizable compound. Thus, after recording an image on the recording material, the recorded image can be cured by irradiation with an active energy ray. Moreover, the structure containing coloring agents, such as a polymerization initiator, dye, and a pigment other than the said component, is preferable, and it can comprise using other components, such as various additives as needed.
In the following description, the term “polymerizable compound” means a polymerizable compound other than a silicon atom-containing polymerizable compound.

-Silicon atom-containing polymerizable compound-
The ink composition of the present invention contains at least one polymerizable compound containing a silicon atom. This silicon atom-containing polymerizable compound is a compound that cures itself when irradiated with active energy rays by the action of a polymerization initiator, which will be described later. As compared with the system containing, the adhesive force with the recording material that comes into direct contact can be enhanced by the action of polymerization by polymerization. Further, the ink composition of the present invention is a combination of a polymerizable compound containing a silicon atom and a polymerizable compound other than this, so that the ink composition of the present invention can be used as compared with the case where only the polymerizable compound is used. And the recording material can be further improved. This is presumably because the polarity of silicon atoms and, for example, silanol groups affect the adhesion to the recording material. As described above, according to the ink composition of the present invention, the image recorded on the recording material can be prevented from being peeled off due to external force, and a robust image excellent in scratch resistance can be formed.
The ink composition of the present invention has high adhesion to any recording material such as metal, a resin such as PET, and glass, but the effect can be sufficiently exerted particularly on glass.
Moreover, according to the ink composition of the present invention, it is possible to suppress a decrease in the density of the ink after curing and to improve the printing density. Furthermore, the ink composition of the present invention can also improve the resistance (light resistance and ozone resistance) to light and oxidizing gas (especially ozone) of an image recorded on an arbitrarily selected recording material. It is also effective in improving the scratch resistance.

  The polymerizable group possessed by the silicon atom-containing polymerizable compound may be a radical polymerizable group or a cationic polymerizable group, and is a (meth) acryloyl group, (meth) acrylamide group, styryl group, allyl ether or acrylic ester. And allyl groups such as vinylamine, vinyl ether and vinyloxyester, epoxy groups, oxetanyl groups and oxiranyl groups. A (meth) acryloyl group is preferred. In the present specification, “(meth) acryloyl” includes methacryloyl and acryloyl, and “(meth) acrylate” is the same.

The silicon atom-containing polymerizable compound is not particularly limited as long as it is a polymerizable compound having a silicon atom, but is preferably a siloxane compound.
Examples of the siloxane compound include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycol. Sidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3 -(Meth) acryloxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyltriethoxysilane and the like.
The siloxane compound is preferably a (meth) acrylate compound having a siloxane bond. More preferred is a compound represented by the following general formula (I).

In formula (I), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 1 to 5 carbon atoms. R ³ represents —O—R ⁴ or a methyl group. R ⁴ represents a methyl group or an ethyl group.

Moreover, when the said silicon atom containing polymeric compound is used for an inkjet recording use, it is preferable that it does not increase the viscosity of an ink composition by addition. For this reason, the silicon atom-containing polymerizable compound is preferably a monomer. The molecular weight of the said silicon atom containing polymeric compound is not specifically limited, For example, 140-1000 are preferable, 160-500 are still more preferable, 180-300 are especially preferable.
Further, the carbon number of the silicon atom-containing polymerizable compound is preferably 2 to 30, more preferably 5 to 15 in consideration of the polarity of the silicon atom-containing polymerizable compound.

  The number of silicon atoms in the silicon atom-containing polymerizable compound is not particularly limited as long as it is at least one.

  A part of the silicon atom-containing polymerizable compound is also available as a commercial product. Examples of the commercially available products include KBE503, KBM503, KBE502, KBM5103 manufactured by Shin-Etsu Chemical Co., Ltd .; Silaplane FM-0721, FM-0711, FM-0725 manufactured by Chisso Corporation, and the like.

Since the silicon atom-containing polymerizable compound can exert the effects of the present invention even when added in a small amount, the influence on curability and sensitivity can be reduced. Moreover, when there are too many addition amounts of the silicon atom containing polymeric compound of this invention with respect to the polymeric compound mentioned later, sclerosis | hardenability and a sensitivity may fall.
Thus, from the viewpoints of adhesion, curability, printing density, sensitivity, etc. of the ink composition, the mass ratio (y / () of the polymerizable compound (x) described later and the silicon atom-containing polymerizable compound (y) will be described. x + y) × 100) is preferably 1 to 20%, more preferably 2 to 15%, and particularly preferably 4 to 12%.
The content of the silicon atom-containing polymerizable compound in the ink composition is preferably determined so as to satisfy the mass ratio in relation to the content of the polymerizable compound described later.

-Polymerizable compound-
The ink composition of the invention further comprises at least one other polymerizable compound in addition to the above-described silicon atom-containing polymerizable compound.

This polymerizable compound is a compound that cures by causing a polymerization reaction by the action of a polymerization initiator described later, specifically, an active species generated from the polymerization initiator when irradiated with active energy rays.
The content of the polymerizable compound in the ink composition of the present invention is 98 to 50% by mass with respect to the total amount (total mass) of the ink composition from the viewpoint of sensitivity based on polymerization reactivity and the viscosity of the ink composition. Is preferable, 95-60 mass% is more preferable, More preferably, it is the range of 90-70 mass%. In this invention, it can select from a radically polymerizable compound and a cationically polymerizable compound. From the viewpoint of combining with the above silicon atom-containing polymerizable compound, the polymerizable compound is preferably a non-basic polymerizable compound.
Hereinafter, the radical polymerizable compound and the cationic polymerizable compound will be mainly described.

-Radically polymerizable compounds-
The radical polymerizable compound is a compound having an ethylenically unsaturated bond capable of radical polymerization, and may be any compound as long as it has at least one ethylenically unsaturated bond capable of radical polymerization in the molecule. , Oligomers, polymers and the like having a chemical form. Only one kind of such radically polymerizable compounds may be used, or two or more kinds thereof may be used in combination at an arbitrary ratio in order to improve desired properties. A polyfunctional compound having two or more functional groups is more preferable than a monofunctional compound. More preferably, two or more polyfunctional compounds are used in combination for controlling performance such as reactivity and physical properties.

  In the ink composition of the present invention, (meth) acrylate can be suitably used as the radical polymerizable compound. Examples of the (meth) acrylate include the following compounds.

  Specific examples of monofunctional (meth) acrylates include hexyl (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-butyl Phenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate Over DOO, glycidyl (meth) acrylate, glycidyl Giro carboxybutyl (meth) acrylate, glycidyl Giro carboxyethyl (meth) acrylate, glycidyl Giro hydroxypropyl (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, tri Methoxysilylpropyl (meth) acrylate, trimethylsilylpropyl (meth) acrylate, polyethylene oxide monomethyl ether (meth) acrylate Oligoethylene oxide monomethyl ether (meth) acrylate, polyethylene oxide (meth) acrylate, oligoethylene oxide (meth) acrylate, oligoethylene oxide monoalkyl ether (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, dipropylene glycol (meth) acrylate , Polypropylene oxide monoalkyl ether (meth) acrylate, oligopropylene oxide monoalkyl ether (meth) acrylate, 2-methacryloyloxytyl succinic acid, 2-methacryloyloxyhexahydrophthalic acid, 2-methacryloyloxyethyl-2- Hydroxypropyl phthalate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl (meta Acrylate, perfluorooctylethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, ethylene oxide modified phenol (meth) acrylate, ethylene oxide modified cresol (meth) acrylate, ethylene oxide modified nonylphenol (meth) acrylate , Polyethylene oxide modified nonylphenol (meth) acrylate, ethylene oxide modified-2-ethylhexyl (meth) acrylate, carbitol (meth) acrylate, oligoester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, methyl ( (Meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate Examples include relate, allyl (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) acrylate, and dimethylaminomethyl (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, ethylene oxide modified bisphenol A di ( ) 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 (meth) acrylate, 1,9-nonanedi (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, tricyclodecane di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) ) Acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethylene glycol Di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol 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, ethoxylated glycerin triacrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate.

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

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

  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.

  In the present invention, the polymerizable compound is selected from (a) at least one trifunctional or higher functional (meth) acrylate and (b) a monofunctional (meth) acrylate and a bifunctional (meth) acrylate. 1 type is preferable in terms of viscosity adjustment, adjustment of crosslinking density, and control of physical properties after curing (strength, adhesiveness, etc.).

  Examples of radically polymerizable compounds other than the listed compounds include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and their salts, esters, urethanes, amides, and the like. Examples thereof include anhydrides, acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes. Specific examples include acrylic acid derivatives such as bis (4-acryloxypolyethoxyphenyl) propane and diacetone acrylamide, methacrylic derivatives such as 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, and allyl glycidyl. Derivatives of allyl compounds such as ether, diallyl phthalate, triallyl trimellitate, etc. are mentioned, and more specifically, “Crosslinking agent handbook” (Yamashita Shinzo, 1981 Taiseisha), “UV / EB curing handbook (raw material) Ed.) "(Kyoto Kato ed., Kobunshi Publishing Co., Ltd. (1985))," Application and Market of UV / EB Curing Technology "(Radtech Research Group, 79 pages (1989), CMC)," Polyester Resin Commercial products or industries described in "Handbook" (by Eiichiro Takiyama, Nikkan Kogyo Shimbun (1988)) Known radical polymerizable or crosslinkable monomers may be used oligomers and polymers.

-Cationically polymerizable compound-
As the cationically polymerizable compound, various known cationically polymerizable monomers known as photocationically polymerizable monomers can be used. Examples of the cationic polymerizable monomer include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and 2001-2001. Examples thereof include vinyl ether compounds, oxetane compounds, and oxirane compounds described in each publication such as 220526.

Examples of the vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, Di- or tri-vinyl ether compounds such as trimethylolpropane trivinyl ether; ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether Le, n- propyl vinyl ether, isopropyl vinyl ether, isopropenyl ether -O- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether.
As the vinyl ether compound, a di- or tri-vinyl ether compound is preferable from the viewpoints of curability, adhesion to a recording material, surface hardness of the formed image, and the like, and a divinyl ether compound is particularly preferable.

  As the cationic polymerizable compound, an oxetane group-containing compound and an oxirane group-containing compound are suitable. These compounds are polymerized when irradiated with active energy rays by the action of the polymerization initiator described later, and cure themselves, and the curing reaction can be carried out in a short time. In addition, it is particularly effective for preventing fading in an image after curing, and can form an image having excellent hue (hue), color density, and sharpness, and light resistance comparable to that of a pigment.

  The oxetane group-containing compound is a compound containing at least one oxetane group (oxetanyl group) in the molecule, and preferably a compound containing one or two oxetane groups in the molecule. ) To (f).

  The oxirane group-containing compound may be appropriately selected from compounds containing at least one oxirane group (oxiranyl group) having an oxirane ring in the molecule, specifically, those usually used as epoxy resins. Examples thereof include conventionally known aromatic epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins. Any of a monomer, an oligomer, and a polymer may be sufficient. Specific examples include the following compounds (i) to (viii).

  When the oxetane group-containing compound (p) and the oxirane group-containing compound (q) are used in combination, the content ratio (mass ratio) p / in that the curability and the light resistance of the image after curing can be more effectively improved. q is preferably in the range of 50/50 to 95/5, and more preferably in the range of 67/33 to 90/10.

-Polymerization initiator-
The ink composition of the present invention preferably contains at least one polymerization initiator that polymerizes and cures the silicon atom-containing polymerizable compound and the other polymerizable compound. The polymerization initiator has absorption in the wavelength region of the active energy ray, and can act on the polymerizable compound and accelerate polymerization and curing when exposed to the active energy ray.

  The polymerization initiator is a compound that generates a chemical change through the action of an active energy ray or the interaction with an electronically excited state of a sensitizing dye to generate at least one of a radical, an acid, or a base. Specifically, active radical species are generated by application of active energy rays to initiate and accelerate polymerization and curing of the polymerizable compound (ie, ink composition), and cationic species are generated by application of active energy rays. Similarly, an initiator for starting and accelerating the polymerization and curing of the polymerizable compound (that is, the ink composition) is included, and can be appropriately selected from the following polymerization initiators.

  In the present invention, “active energy rays” are actinic rays that generate radicals or cations from a polymerization initiator, and include ultraviolet rays (UV light), visible rays, γ rays, α rays, X rays, and other electron rays. As specific light sources, for example, LD, LED, fluorescent lamp, low-pressure mercury lamp, high-pressure mercury lamp, metal halide lamp, carbon arc lamp, xenon lamp, chemical lamp, and the like can be applied. Preferred light sources include LEDs, high pressure mercury lamps, and metal halide lamps.

  As an example of a polymerization initiator, what is known among those skilled in the art can be used without a restriction | limiting. Specifically, for example, Bruce M. Monroe et al., Chemical Revue, 93, 435 (1993), RSD Davidson, Journal of Photochemistry and biology A: Chemistry, 73.81 (1993), JP Faussier "Photoinitiated Polymerization-Theory and Applications ": Rapra Review vol. 9, Report, Rapra Technology (1998)., M. Tsunooka et al., Prog. Polym. Sci., 21, 1 (1996). In addition, it is described as a chemical amplification type photoresist or a compound used for photocationic polymerization in “Organic Materials for Imaging” (see Organic Electronics Materials Research Group, Bunshin Publishing (1993), p. 187 to 192). Compounds. Furthermore, FDSaeva, Topics in Current Chemistry, 156, 59 (1990) .GG Maslak, Topics in Current Chemistry, 168, 1 (1993) .HB Shuster et al, JACS, 112, 6329 (1990). Examples of the compound group described in IDFEaton et al, JACS, 102, 3298 (1980). And the like that undergo oxidative or reductive bond cleavage through interaction with the electronically excited state of the sensitizing dye. .

  Preferred polymerization 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 salt compounds, (h) metallocene compounds, (i) active ester compounds, (j) compounds having a carbon halogen bond, and the like.

  Preferred examples of the (a) aromatic ketones include compounds having a benzophenone skeleton or a thioxanthone skeleton described in “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” JPFOUASSIER JFRABEK (1993), p. 77-117. Can be mentioned. More preferable examples of the 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, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, dialkoxybenzophenone described in JP-B-60-26483 Benzoin ethers described in JP-B-60-26403, JP-A-62-81345, JP-B-1-34242, US Pat. No. 4,318,791, and α described in European Patent 0284561A1. -Aminobenzophenones, p-di described in JP-A-2-211452 Dimethylaminobenzoyl) benzene, a thio-substituted aromatic ketone described in JP-A-61-194062, an acylphosphine sulfide described in JP-B-2-9597, an acylphosphine described in JP-B-2-9596, Examples thereof include thioxanthones described in JP-B-63-61950, coumarins described in JP-B-59-42864, and the like.

  Examples of the (b) aromatic onium salt compound include elements belonging to Groups 15, 16, and 17 of the Long 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 described in the specifications of U.S. Pat. Nos. 297442, 279210, and 422570, and U.S. Pat. Nos. 3,902,144, 4,933,377, 4,760013, 4,734,344, and 2,833,827 Salts (such as benzenediazonium which may have a substituent), diazonium salt resins (formaldehyde resin of diazodiphenylamine), N-alkoxypyridinium salts and the like (for example, US Pat. No. 4,743,528, JP, Sho 63-13834 , JP-A-63-142345, JP-A-63-142346, and JP-B-46-42363, specifically 1-methoxy-4-phenylpyridinium tetrafluoroborate. Etc.), and compounds described in JP-B Nos. 52-147277, 52-14278, and 52-14279. Generates radicals and acids as active species.

  The (c) organic peroxide includes an organic compound having one or more oxygen-oxygen bonds in the molecule, and specific examples include 3,3 ′, 4,4′-tetra- (t-butylperoxide. Oxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (t-amylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (t-hexylperoxycarbonyl) benzophenone, 3, , 3 ′, 4,4′-tetra- (t-octylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (cumylperoxycarbonyl) benzophenone, 3,3 ′, 4,4 ′ Preferable examples include peroxide ester systems such as tetra- (p-isopropylcumylperoxycarbonyl) benzophenone and di-t-butyldiperoxyisophthalate.

  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) ) Biimidazole, 2,2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4 4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o- Trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and the like.

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

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

  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. is 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 dicyclopentadienyl-Ti-dichloride, dicyclopentadienyl-Ti-bis-phenyl, dicyclopentadienyl-Ti-bis-2,3,4,5,6. -Pentafluorophenyl-1-yl, dicyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophenyl-1-yl, dicyclopentadienyl-Ti-bis-2,4,6 -Trifluorophenyl-1-yl, dicyclopentadienyl-Ti-2,6-difluorophenyl-1-yl, dicyclopentadienyl-Ti-bis-2,4-difluorophenyl-1-yl, dimethyl Cyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophenyl-1-yl, dimethylcyclopentadienyl-Ti-bis-2 3,5,6-tetrafluorophenyl-1-yl, dimethylcyclopentadienyl-Ti-bis-2,4-difluorophenyl-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 (cyclopentadienyl) bis [2 , 6-Difluoro-3- (N-butylbialoyl-amino) phenyl] titanium and the like.

  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 described in JP-A-60-198538 and JP-A-53-133022, European Patent Nos. 099672, 84515, 199672, 0441115, and 0101122. 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-4-365048. An iminosulfonate compound described in JP-B-62-62 No. 3, JP-B-63-14340, and include the compounds described in each publication of JP-59-174831.

  Preferable examples of the compound (j) having a carbon halogen bond include compounds described in Wakabayashi et al., Bull. Chem. Soc. Japan, 42, 2924 (1969), compounds described in British Patent No. 1388492, Examples include compounds described in JP-A-53-133428, compounds described in German Patent No. 3333724, and the like.

  Further, compounds described in J. Org. Chem. 29, 1527 (1964) by FC Schaefer et al., Compounds described in JP-A-62-258241, compounds described in JP-A-5-281728, and the like are listed. be able to. The compound described in German Patent No. 2641100, the compound described in German Patent No. 3333450, the compound group described in German Patent No. 3021590, the compound group described in German Patent No. 3021599, etc. can also be mentioned.

  Preferred specific examples of the compounds represented by the above (a) to (j) are listed below.

  The content of the polymerization initiator in the ink composition is in the range of 0.5 to 20% by mass with respect to the total amount of the aforementioned silicon atom-containing polymerizable compound and other polymerizable compounds and the polymerization initiator. Preferably, the range of 1-12 mass% is more preferable. When the content is particularly in the above range, the curing rate is high and good curability is obtained, which is effective for recording robust images. Further, the scratch resistance when the image is rubbed does not deteriorate.

-Colorant-
The ink composition of the present invention can be configured to contain a colorant as required to form a visible image. There is no restriction | limiting in particular in this coloring agent, According to a use etc., a well-known various coloring material (especially pigment, dye) can be selected suitably, and can be used. The present invention has the effect of increasing the printing density particularly in dyes. In addition, the ink composition of the present invention is suitable for a system using a dye because it is not necessary to consider the reaction between the pigment dispersant and the silicon atom-containing polymerizable compound. However, the present invention is not limited to dyes. The dye includes water-soluble dyes and oil-soluble dyes, and oil-soluble dyes are preferred in the present invention. Hereinafter, it demonstrates in detail centering on dye and a pigment.

<dye>
As the dye, conventionally known dyes can be appropriately selected and used. Specific examples include the dyes described in paragraphs [0023] to [0089] of JP-A No. 2002-114930.

  Examples of yellow dyes include, for example, phenols, naphthols, anilines, pyrazolones, pyridones, aryl or heteryl azo dyes having open-chain active methylene compounds as coupling components, for example, open-chain active methylene compounds as coupling components Azomethine dyes having, for example, methine dyes such as benzylidene dyes and monomethine oxonol dyes, for example, quinone dyes such as naphthoquinone dyes and anthraquinone dyes, and other dyes include quinophthalone dyes, nitro, Nitroso dyes, acridine dyes, acridinone dyes and the like can be mentioned.

  Examples of the magenta dye include phenols, naphthols, anilines, pyrazolones, pyridones, pyrazolotriazoles, and ring-closing active methylene compounds (for example, dimedone, barbituric acid, 4-hydroxycoumarin) as coupling components. Derivatives), electron-rich heterocycles (eg, pyrrole, imidazole, thiophene, thiazole derivatives), or aryl or heteryl azo dyes, eg, azomethine dyes having pyrazolones, pyrazolotriazoles as coupling components, eg, arylidene dyes, styryl Dyes, merocyanine dyes, methine dyes such as oxonol dyes, carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, such as naphthoquinone, anthraquinone, anthrone Quinone dyes such Rapiridon, can be mentioned condensed polycyclic dyes such as, for example, dioxazine dye.

  Examples of the cyan dye include azomethine dyes such as indoaniline dyes and indophenol dyes, cyanine dyes, oxonol dyes, polymethine dyes such as merocyanine dyes, carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, and xanthene dyes, Examples of phthalocyanine dyes and anthraquinone dyes include phenols, naphthols, anilines, pyrrolopyrimidin-one, aryl or heteryl azo dyes having pyrrolotriazin-one derivatives, and indigo / thioindigo dyes as coupling components.

  Each of the above dyes may exhibit yellow, magenta, and cyan colors only after a part of the chromophore is dissociated. In this case, the counter cation is an inorganic cation such as an alkali metal or ammonium. Alternatively, it may be an organic cation such as pyridinium, quaternary ammonium salt, or a cationic polymer having a partial structure thereof.

  The dye that can be used in the present invention is preferably oil-soluble. “Oil-soluble” specifically means that the solubility in water at 25 ° C. (the mass of the dye dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0. .1 g or less. Therefore, so-called water-insoluble oil-soluble dyes are preferably used.

The dye used in the present invention preferably has an oil-solubilizing group introduced into the above-described dye matrix in order to dissolve the necessary amount in the ink composition.
Examples of the oil-solubilizing groups include long-chain or branched alkyl groups, long-chain or branched alkoxy groups, long-chain or branched alkylthio groups, long-chain or branched alkylsulfonyl groups, long-chain or branched acyloxy groups, long-chain or branched alkoxycarbonyl groups. A long chain or branched acyl group, a long chain or branched acylamino group, a long chain or branched alkylsulfonylamino group, a long chain or branched alkylaminosulfonyl group, and an aryl group containing these long chain or branched groups, an aryloxy group, An aryloxycarbonyl group, an arylcarbonyloxy group, an arylaminocarbonyl group, an arylaminosulfonyl group, an arylsulfonylamino group, etc. are mentioned.

  In addition, a water-soluble dye having a carboxylic acid group or a sulfonic acid group is converted into an oil-solubilizing alkoxycarbonyl group, aryloxycarbonyl group, alkylaminosulfonyl group using a long chain or branched alcohol, amine, phenol, or aniline derivative. The dye may be obtained by conversion to an arylaminosulfonyl group.

  The oil-soluble dye preferably has a melting point of 200 ° C. or lower, more preferably has a melting point of 150 ° C. or lower, and still more preferably has a melting point of 100 ° C. or lower. By selecting a low melting point dye as the oil-soluble dye, the crystal precipitation of the dye in the ink composition is suppressed, and the storage stability of the ink composition can be improved.

  In addition, it is desirable that the oxidation potential is noble (high) in order to improve the resistance to the discoloration, in particular, the oxidizing substance such as ozone and the curing characteristics. For this reason, as the oil-soluble dye, those having an oxidation potential nobler than 1.0 V (vs SCE) are preferable. A higher oxidation potential is preferable, an oxidation potential of 1.1 V (vs SCE) or higher is more preferable, and a voltage of 1.15 V (vs SCE) or higher is particularly preferable.

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

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

Examples of cyan dyes include dyes represented by formulas (I) to (IV) described in JP-A No. 2001-181547, and paragraphs [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) are preferable, and specific examples thereof include paragraphs [0052] to [0066] of JP-A No. 2001-181547 and JP-A No. 2002. And the compounds described in paragraph Nos. [0079] to [0081] of JP-A-1221414.
Particularly preferred dyes are phthalocyanine dyes represented by general formulas (CI) and (C-II) described in paragraph numbers [0133] to [0196] of JP-A No. 2002-121414, A phthalocyanine dye represented by (C-II) is preferred. Specific examples thereof include the compounds described in JP-A No. 2002-121414, paragraph numbers [0198] to [0201]. The oil-soluble dyes of the formulas (I) to (IV), (IV-1) to (IV-4), (CI), and (C-II) are not only cyan but also black ink or green ink. The ink may be used for any color ink.

-Oxidation potential-
The oxidation potential value (Eox) of the dye in the present invention can be easily measured by those skilled in the art. As for this method, for example, “New Instrumental Methods in Electrochemistry” by P. Delahay (1954, published by Interscience Publishers), AJBard et al. “Electrochemical Methods” (1980, published by John Wiley & Sons), Akira Fujishima et al. It is described in the book "Electrochemical measurement method" (1984, published by Gihodo Publishing Co., Ltd.).

The oxidation potential is determined by dissolving 1 × 10 ⁻² to 1 × 10 ⁻⁶ mol / liter of the test sample in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate. The voltammetry apparatus approximates the oxidation wave when carbon (GC) is swept to the oxidation side (noble side) using carbon (GC) as the working electrode and the rotating platinum electrode as the counter electrode. The intermediate potential value of the line segment formed by the intersection of the straight line and the intersection of the straight line and the saturation current line (or the intersection of the straight line parallel to the vertical axis passing through the peak potential value) is a value for the SCE (saturated calomel electrode). Measure as Although this value may be deviated by several tens of mil volts due to the influence of the liquid potential difference or the liquid resistance of the sample solution, the reproducibility of the potential can be ensured by inserting a standard sample (for example, hydroquinone). The supporting electrolyte and solvent to be used can be selected appropriately depending on the oxidation potential and solubility of the test sample. The supporting electrolyte and the solvent that can be used are described in pages 101 to 118 of Akira Fujishima et al., “Electrochemical measurement method” (published by Gihodo Publishing Co., 1984). In the concentration range of the measurement solvent and the phthalocyanine compound sample, the oxidation potential in a non-association state is measured.
The value of Eox represents the ease of transfer of electrons from the sample to the electrode. The greater the value of Eox, that is, the higher the oxidation potential, the less transfer of electrons from the sample to the electrode, in other words, oxidation. Indicates difficult.

  Specific examples of suitable dyes in the present invention are shown below. However, the present invention is not limited to these specific examples.

<Pigment>
Next, the pigment will be described in detail. The pigment is not particularly limited, and all commercially available organic pigments and inorganic pigments, or insoluble resins etc. dispersed in a pigment as a dispersion medium, and the resin grafted on the pigment surface And the like. Moreover, what dye | stained the resin particle with dye can be used.

  Examples of pigments include “Dictionary of Pigments” (edited by Seijiro Ito, 2000), W. Herbst, K. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, Examples thereof include pigments described in JP2003-26978A and JP2003-342503A.

  Specific examples of organic pigments and inorganic pigments include C.I. I. Pigment Yellow 1 (Fast Yellow G, etc.), C.I. I. Monoazo pigments such as CI Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as C.I. Pigment Yellow 17; I. Non-benzidine azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Condensed azo pigments such as C.I. Pigment Yellow 95 (condensed azo yellow GR and the like), C.I. I. Pigment Yellow 115 (quinoline yellow lake, etc.), etc., acidic dye lake pigments, C.I. I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.), C.I. I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow and the like).

  As C.I. red or magenta color, C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Disazo pigments such as CI Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Azo lake pigments such as C.I. Pigment Red 57: 1 (Brilliant Carmine 6B); I. Condensed azo pigments such as C.I. Pigment Red 144 (condensed azo red BR, etc.); I. Pigment Red 174 (Phloxine B Lake, etc.) and other acidic dye lake pigments; I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G 'lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as CI Pigment Red 88 (Thioindigo Bordeaux and the like), C.I. I. Perinone pigments such as CI Pigment Red 194 (perinone red, etc.); I. Perylene pigments such as C.I. Pigment Red 149 (perylene scarlet, etc.), C.I. I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Quinacridone pigments such as C.I. Pigment Red 122 (quinacridone magenta, etc.); I. Pigment Red 180 (Isoindolinone Red 2BLT, etc.), etc., isoindolinone pigments, C.I. I. And alizarin lake pigments such as CI Pigment Red 83 (Madder Lake, etc.).

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

  As a pigment exhibiting green, C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).

  As a pigment exhibiting an orange color, C.I. I. Pigment Orange 66 (Isoindoline Orange) and the like, C.I. I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

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

Further, as white pigments, basic lead carbonate (2PbCO ₃ Pb (OH) ₂ ; so-called silver white), zinc oxide (ZnO; so-called zinc white), titanium oxide (TiO ₂ ; so-called titanium white), strontium titanate (SrTiO ₃ ; so-called titanium strontium white).

  Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable. Therefore, it has a high hiding power and coloring power as a pigment, and further has an acid or alkali. Excellent durability against other environments. Therefore, titanium oxide is suitable as the white pigment. Moreover, other white pigments (may be other than the listed white pigments) may be contained as required.

  The pigment can be used as a dispersion dispersed in a dispersion medium together with a dispersant as required. For dispersing the pigment, for example, a ball mill, sand mill, attritor, roll mill, jet mill, homogenizer, paint shaker, kneader, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, etc. A dispersing device can be used.

When dispersing the pigment, it is possible to add a dispersant or a dispersion aid.
Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular weight copolymer, a modified polyacrylate, a fatty acid An aromatic polyvalent carboxylic acid, a naphthalenesulfonic acid formalin condensate, a polyoxyethylene alkyl phosphate ester, a pigment derivative, and the like can be given. Commercially available polymer dispersants such as Solsperse series manufactured by Zeneca can also be suitably used.
As the dispersion aid, a synergist corresponding to various pigments can be used.
The dispersant and dispersion aid are preferably added in the range of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

  In the ink composition, as a dispersion medium for various components such as pigments, a solvent may be added, or a solvent-free solvent may be used and the polymerizable compound described above, which is a low molecular weight component, may be used as the dispersion medium. However, the ink composition of the present invention is a radiation curable ink and is preferably solvent-free because it is cured after the ink composition is applied onto a recording material. 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, a polymerizable compound is used as the dispersion medium, and it is preferable to select a polymerizable compound having the lowest viscosity among them in terms of dispersion suitability and handling property of the ink composition.

  The average particle size of the pigment is preferably in the range of 0.08 to 0.5 μm, and the maximum particle size is preferably 10 μm or less, more preferably 3 μm or less, selection of pigment, dispersant, dispersion medium, dispersion It is desirable to set conditions and filtration conditions. By controlling the particle size in this way, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

  The colorant is preferably added in an amount of 0.05 to 20% by mass, more preferably 0.2 to 10% by mass, based on the total mass of the ink composition. When an oil-soluble dye is used as the colorant, the content is particularly preferably 0.2 to 6% by mass with respect to the total mass of the ink composition.

-Additives-
In the ink composition of the present invention, in addition to the above-mentioned components, a sensitizing dye, a co-sensitizer, an ultraviolet absorber, etc. may be used in combination as additives and other components as required for the purpose and application. Can do. Hereinafter, the additive and other components will be described.

-Sensitizing dye-
In the present invention, a sensitizing dye can be added for the purpose of improving the sensitivity of the polymerization initiator. Hereinafter, the sensitizing dye will be described.

  Examples of the sensitizing dye include those belonging to the compounds listed below and having an absorption wavelength in a wavelength region of 350 nm to 450 nm.

  For example, polynuclear aromatics (eg, pyrene, perylene, triphenylene, 2-ethyl-9,10-dimethoxyanthracene, etc.), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal, etc.) , Cyanines (eg, thiacarbocyanine, oxacarbocyanine, etc.), merocyanines (eg, merocyanine, carbomerocyani, etc.), thiazines (eg, thionine, methylene blue, toluidine blue, etc.), acridines (eg, Acridine orange, chloroflavin, acriflavine, etc.), anthraquinones (eg, anthraquinone, etc.), squaliums (eg, squalium, etc.), coumarins (eg, 7-diethylamino-4-methylcoumarin, etc.), etc. Mentioned That.

  Preferred examples of the sensitizing dye in the present invention include compounds represented by the following general formulas (vi) to (x).

In the general 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 adjacent carbon atoms. R ⁵¹ and R ⁵² each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁵¹ and R ⁵² may be bonded to each other to form an acidic nucleus of the dye. W represents an oxygen atom or a sulfur atom.

In the general formula (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—. W is synonymous with W in the general formula (vi).

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

In the general formula (ix), A ³ and A ⁴ each independently represent —S—, —NR ⁶² —, or —NR ⁶³ —, and R ⁶² and R ⁶³ each independently represent a substituted or unsubstituted group. A substituted alkyl group or a substituted or unsubstituted aryl group is represented. L ⁴ and L ⁵ each independently represent a nonmetallic atomic group that forms a basic nucleus of a dye together with A ³ or A ⁴ and an adjacent 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 general formula (x), R ⁶⁶ represents an aromatic ring or a hetero ring which may have a substituent. A ⁵ represents an oxygen atom, a sulfur atom, or NR ⁶⁷ —. R ⁶⁴ , R ⁶⁵ and R ⁶⁷ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group. R ⁶⁷ and R ⁶⁴ , and R ⁶⁵ and R ⁶⁷ may be bonded to each other to form an aliphatic or aromatic ring.

  Hereinafter, preferable specific examples of the compounds represented by the general formulas (vi) to (x) will be given. However, the present invention is not limited to these.

The said sensitizing dye may be used individually by 1 type, and may use 2 or more types together.
The content of the sensitizing dye in the ink composition is preferably 0.01 to 20% by mass with respect to the total amount (total mass) of the ink composition from the viewpoint of the colorability of the ink composition, and preferably 0.1 to 15 mass% is more preferable, More preferably, it is the range of 0.5-10 mass%. Further, the content ratio (a / c) in the ink composition of the sensitizing dye (a) and the polymerization initiator (c) is from the viewpoint of improving the decomposition rate of the polymerization initiator and the transparency of irradiated light. The mass ratio is preferably a / c = 100 to 0.5, more preferably a / c = 50 to 1, and still more preferably a / c = 10 to 1.5.

-Co-sensitizer-
The ink composition of the present invention may further contain a known compound having a function of further improving sensitivity or suppressing polymerization inhibition by oxygen as a cosensitizer.

  Examples of co-sensitizers include amines such as M.I. R. Sander et al., “Journal of Polymer Society”, Vol. 10, 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, Japanese Patent Publication No. 59-138205. No. 60-84305, JP-A 62-18537, JP-A 64-33104, Research Disclosure 33825, and the like. 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 such as thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142772, No. 56-75643, such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercapto. And naphthalene.

Other examples of the co-sensitizer include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in JP-B-48-42965 (eg, tributyltin acetate), JP-B 55- No. 34414, a hydrogen donor described in JP-A-6-308727 (eg, trithiane), a phosphorus compound described in JP-A-6-250387 (eg diethylphosphite), Examples include Si-H and Ge-H compounds described in 191605.
The addition amount is appropriately selected according to the purpose, but is generally about 0.01 to 10% by mass with respect to the total amount (total mass) of the ink composition.

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

-Polymerization inhibitor-
A polymerization inhibitor can be added to the ink composition of the present invention. Polymerization inhibitors include phenolic hydroxyl group-containing compounds, quinones, N-oxide compounds, piperidine-1-oxyl free radical compounds, pyrrolidine-1-oxyl free radical compounds, N-nitrosophenylhydroxylamines, And a compound selected from the group consisting of cationic dyes.

  Specifically, haloquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, resorcinol, catechol, t-butylcatechol, hydroquinone monoalkyl ether (for example, hydroquinone monomethyl ether, hydroquinone monobutyl ether), Benzoquinone, 4,4-thiobis (3-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2,6,6-tetramethylpiperidine and its Derivatives, di-t-butyl nitroxide, 2,2,6,6-tetramethylpiperidine-N-oxide and derivatives thereof, piperidine 1-oxyl free radical, 2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-Oki So-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-acetamido-2,2,6 6-tetramethylpiperidine 1-oxyl free radical, 4-maleimido-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-phosphonoxy-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 3-carboxy-2,2,5,5-tetramethylpyrrolidine 1-oxyl free radical, N-nitrosophenylhydroxylamine cerium salt, N-nitrosophenylhydroxylamine aluminum salt, crystal violet, methyl violet, Ethyl violet, Fine Victoria Pure Blue BOH, and the like.

  Of these, hydroquinone monoalkyl ethers such as hydroquinone monomethyl ether and hydroquinone monobutyl ether, 4,4′-thiobis (3-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-methyl-6-t) Hindered phenols such as -butylphenol) are preferred.

  The content of the polymerization inhibitor in the ink composition is preferably 10,000 to 30,000 ppm, more preferably 10,000 to 20,000 ppm, and even more preferably 10,000 to 15,000 ppm with respect to the total amount (total mass) of the composition.

-UV absorber-
An ultraviolet absorber can be added to the ink composition of the present invention from the viewpoint of improving the weather resistance of the resulting image and preventing discoloration.
Examples of the ultraviolet absorber are described in JP-A-58-185679, JP-A-61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194843, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492 and 56-21141 Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP The triazine compounds described in JP-A-8-501291, Research Disclosure No. Examples thereof include compounds described in US Pat. No. 24239, compounds that emit fluorescence by absorbing ultraviolet rays typified by stilbene and benzoxazole compounds, and so-called fluorescent brighteners.
The addition amount is appropriately selected according to the purpose, but is generally about 0.01 to 10% by mass with respect to the total amount (total mass) of the ink composition.

-Antioxidant-
An antioxidant may be added to the ink composition of the present invention to improve stability. Examples of the antioxidant include European published patents, 223739, 309401, 309402, 310551, 310552, 359416, and 3435443. JP, 54-85535, 62-262417, 63-113536, 63-163351, JP-A-2-262654, JP-A-2-71262, Examples thereof include those described in Kaihei 3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275, and the like.
The addition amount is appropriately selected according to the purpose, but is generally about 0.01 to 10% by mass with respect to the total amount (total mass) of the ink composition.

-Anti-fading agent-
Various organic and metal complex anti-fading agents can be added to the ink composition of the present invention. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. Examples of the anti-fading agent based on the metal complex include nickel complexes, zinc complexes, and the like. No. 17643, Nos. VII to I, J. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .
The addition amount is appropriately selected according to the purpose, but is generally about 0.01 to 10% by mass with respect to the total amount (total mass) of the ink composition.

-Conductive salts-
Conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, and dimethylamine hydrochloride can be added to the ink composition of the present invention for the purpose of controlling ejection properties.

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

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

In addition to the above, the ink composition of the present invention has, for example, leveling additives, matting agents, waxes for adjusting film properties, polyolefins, and adhesion to recording materials such as PET. For the purpose of improving, a tackifier or the like that does not inhibit polymerization can be contained.
As the tackifier, specifically, a high-molecular-weight adhesive polymer described in JP-A-2001-49200, 5-6p (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms). Copolymers composed of esters with alcohols having an ester, esters of (meth) acrylic acid with alicyclic alcohols having 3 to 14 carbon atoms, and esters of (meth) acrylic acid with aromatic alcohols having 6 to 14 carbon atoms And low molecular weight tackifying resin having a polymerizable unsaturated bond.

{Preferred physical properties of ink composition}
When the ink composition of the present invention is applied to inkjet recording, the ink viscosity at the temperature at the time of ejection is preferably 5 to 30 mPa · s, and more preferably 7 to 20 mPa · s, in consideration of ejection properties. For this reason, it is desirable to adjust and determine a composition ratio suitably so that it may become the said range.
In addition, the viscosity of the ink composition at room temperature (25 ° C.) is preferably 7 to 120 mPa · s, and more preferably 10 to 80 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 monomer can be reduced, and odor can be reduced. Dot bleeding at the time of landing can be suppressed, and as a result, image quality can be improved.

The surface tension of the ink composition of the present invention is preferably 20 to 40 mN / m, and more preferably 20 to 30 mN / m.
Further, when the ink composition of the present invention is recorded on various recording materials such as polyolefin, PET, coated paper, and non-coated paper, the surface tension is preferably 20 mN / m or more from the viewpoint of bleeding and penetration, In terms of wettability, it is preferably 30 mN / m or less.

The ink composition of the present invention can be suitably used as an ink for inkjet recording. There are no particular restrictions on the ink jet recording method, for example, a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electrical signal that is acoustic Either an acoustic ink jet system that irradiates ink by irradiating it with ink instead of using a beam, or a thermal ink jet system that uses ink to form bubbles by heating the ink and use the generated pressure. Also good. The inkjet recording method includes a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different concentrations, and colorless and transparent. A method using ink.
Among these, the ink is suitable as a drop-on-demand type (pressure pulse type) ink jet recording ink using a piezo element. The ink composition of the present invention can be used as a printing ink in addition to inkjet recording.

<Image forming method>
The ink composition of the present invention includes an image forming method including an image recording step of recording an image on a recording material by ink jet recording that discharges the ink composition of the present invention, and a recording material using the ink composition of the present invention. And an image forming method including an image recording step of recording an image on the recording material and an image curing step of irradiating and curing an active energy ray (active ray) on the image recorded on the recording material in the image recording step. Can do.
That is, the image recording method of the present invention may be a method including only an image recording step of forming an image by ink jet recording, or a method combining this with an image curing step. Furthermore, a method in which an image is recorded by a method other than inkjet recording in the image recording process, and an image curing process is combined with this may be used.
In the image curing step according to the present invention, an active energy ray is used, and after recording an image on a recording material in the image recording step, the polymerizable image contributes to imaging by irradiating the recorded image with the active energy ray. The polymerization and curing of the compound proceeds, and it is possible to form an image that is cured well and has high fastness.

  In the image recording step, it is preferable to apply an ink jet recording method using an ink jet printer. Specifically, in the image recording step, an aspect in which an ink image is inkjet-recorded by discharging the ink composition from, for example, an ejection nozzle of an inkjet printer is preferable. In the ink jet recording method, image recording is performed on a recording material using the ink composition of the present invention, but there are no particular restrictions on the ink discharge nozzles (for example, for an ink jet printer) used at that time, and the purpose and application It can be appropriately selected according to the like. There is no restriction | limiting in particular in an inkjet recording system, and it is as above-mentioned specifically.

  In the image curing step, an exposure process for accelerating polymerization and curing can be performed using a light source that emits active energy rays in a wavelength region corresponding to the sensitive wavelength of the ink composition. Specifically, a light source that emits active rays belonging to a wavelength region of 250 to 450 nm, for example, LD, LED, fluorescent lamp, low-pressure mercury lamp, high-pressure mercury lamp, metal halide lamp, carbon arc lamp, xenon lamp, chemical lamp, etc. It can be suitably performed. Preferred light sources include LEDs, high pressure mercury lamps, and metal halide lamps. What is necessary is just to select exposure time and a light quantity suitably according to the grade of the polymerization hardening of the polymeric compound in this invention.

-Recording material-
As the recording medium material, either an ink-permeable recording material or an ink-impermeable recording material can be used.

  Examples of the ink-permeable recording material include plain paper, inkjet exclusive paper, coated paper, electrophotographic co-paper, cloth, non-woven fabric, porous film, and polymer absorber. These are described as “recording materials” in Japanese Patent Application Laid-Open No. 2001-181549.

From the viewpoint of effectively expressing the effects of the present invention, it is preferable to use a non-ink-permeable (non-absorbing) recording material. Even for non-penetrating materials such as film, metal, glass, etc., the ink itself is cured by the exposure process after recording. can do.
Examples of the ink-impermeable recording material include art paper, synthetic resin, rubber, resin-coated paper, glass, metal, earthenware, and wood. In addition, in terms of adding each function, a base material obtained by combining a plurality of these materials can also be used.

As the synthetic resin, any synthetic resin can be used. For example, polyester resins such as polyethylene terephthalate and polybutadiene terephthalate; polyolefin resins such as polyvinyl chloride, polystyrene, polyethylene, polyurethane, and polypropylene; and acrylic resins, Examples include polycarbonate, acrylonitrile-butadiene-styrene copolymer, diacetate, triacetate, polyimide, cellophane, and celluloid.
There is no restriction | limiting in particular about the shape of the base material using a synthetic resin, and its thickness, Any of a film form, a card | curd shape, or a block shape may be sufficient, and it can select suitably according to the desired objective. The synthetic resin may be either transparent or opaque.

  The use form of the synthetic resin is one of the preferred forms used in the form of a film or sheet used for so-called soft packaging, and various non-absorbable plastics and films thereof can be used. Examples of various plastics films include PET films, OPS films, OPP films, ONy films, PVC films, PE films, and TAC films.

  Examples of the resin-coated paper include a paper support in which one side or both sides of the paper is coated with a polyolefin resin and the like, and a paper support in which both sides of the paper are laminated with a polyolefin resin is particularly preferable.

  As described above, according to the image recording using the ink composition of the present invention (the image forming method of the present invention), it is possible to obtain a high-quality, high-intensity and robust image, The recorded matter of the present invention is excellent in image fastness, light resistance and ozone resistance.

  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” and “%” are based on mass.

−Preparation of recording material−
As recording materials for recording images, a polyethylene terephthalate sheet (PET sheet) having a thickness of 50 μm and a hard glass having a thickness of 2.5 mm were prepared.

[Example 1]
Each component having the following composition was stirred and mixed to obtain a magenta ink (1) of the present invention.
・ The following silicon atom-containing polymerizable compound (1): 2.0 g
(Product name: KBE503: manufactured by Shin-Etsu Chemical Co., Ltd.)
・ ACMO: 18.0g
(Manufactured by Kojin Co., Ltd .; polymerizable compound)
・ Irgacure 1870 ... 0.6g
(Ciba Specialty Chemicals; polymerization initiator)
・ The following magenta dye M-1 (oil-soluble dye): 0.2 g

[Example 2]
Magenta ink was prepared in the same manner as in Example 1 except that the addition amount of the silicon atom-containing polymerizable compound (1) was changed to 1.0 g and the addition amount of ACMO (polymerizable compound) was changed to 19.0 g. Got.

[Examples 3 to 5]
A magenta ink was obtained in the same manner as in Example 1 except that the silicon atom-containing polymerizable compound (1) was changed to the compounds shown in Table 1 in Example 1.

[Comparative Example 1]
A comparative magenta ink (1 ′) was obtained in the same manner as in Example 1 except that the silicon atom-containing polymerizable compound was not added and the amount of ACMO (polymerizable compound) added was changed to 20 g. It was.

(Image recording and evaluation)
Each of the obtained magenta ink of the present invention and the comparative magenta ink obtained as described above is sequentially loaded into an ink jet printer (printing density 300 dpi, droplet ejection frequency 1 kHz, nozzle number 64), and each ink is ejected onto hard glass and PET sheet. A color image was recorded, and after the recording, irradiation was performed using a UV lamp (manufactured by Fusion) under conditions of UV-A (320 to 390 nm) energy of 500 mJ / cm ² to prepare a color image sample. Subsequently, the following evaluation was performed on each of the obtained color images. The evaluation results are shown in Table 1 below.

1. Print Density The print density of the obtained image was measured using a reflection density meter (X-rite 938, manufactured by X-rite).

2. Adhesion When a color image (solid image: size 90 mm x 120 mm), which is a cured film, is cut into a grid-like cut with a cutter, and then the adhesive tape is applied to the entire surface of the color image and the adhesive tape is peeled off. The remaining state of the color image remaining on the hard glass or the PET sheet was visually observed and evaluated according to the following criteria.
[Evaluation criteria]
○: Almost no color image peeling was observed.
Δ: Some peeling of the color image was observed, but was practically acceptable.
X: Peeling of color image was remarkably recognized.

※表１中、「組成比」は、珪素原子含有重合性化合物と重合性化合物との総量に対する珪素原子含有重合性化合物の割合を示す。

* In Table 1, “composition ratio” indicates the ratio of the silicon atom-containing polymerizable compound to the total amount of the silicon atom-containing polymerizable compound and the polymerizable compound.

As shown in Table 1, in the magenta inks (1) to (5) of the present invention using a silicon atom-containing polymerizable compound and another polymerizable compound in combination, the recorded color image is not easily peeled off. It was possible to record a robust color image easily and stably. In particular, the effect of improving adhesion was remarkably recognized for glass. The printing density was also good.
On the other hand, the comparative magenta ink (1 ′) which does not contain the silicon atom-containing polymerizable compound was liable to peel off from both glass and PET, and had poor adhesion.

Claims (11)

  An ink composition comprising a polymerizable compound and a polymerizable compound containing a silicon atom.   2. The mass ratio (y / (x + y) × 100) between the polymerizable compound (x) and the polymerizable compound (y) containing the silicon atom is 1 to 20%. Ink composition.   3. The ink composition according to claim 1, wherein the polymerizable compound containing a silicon atom is a (meth) acrylate compound having a siloxane bond. The ink composition according to claim 1, wherein the polymerizable compound containing a silicon atom is a compound represented by the following general formula (I).

(In the general formula (I), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 1 to 5 carbon atoms. R ³ represents —O—R ⁴ or a methyl group. R ⁴ represents a methyl group or an ethyl group.)   The ink composition according to claim 1, further comprising a polymerization initiator.   The ink composition according to any one of claims 1 to 5, wherein the colorant contains a pigment or an oil-soluble dye.   The ink composition according to claim 1, wherein the ink composition is used for ink jet recording.   An image forming method comprising: an image recording step of recording an image on a recording material by ink jet recording that discharges the ink composition according to claim 1. An image recording step of recording an image on a recording material using the ink composition according to claim 1;
An image curing step of irradiating and curing an active energy ray on the image recorded on the recording material in the image recording step;
An image forming method comprising:   The image forming method according to claim 9, wherein the image recording step records the image by inkjet recording in which the ink composition is discharged.   A recorded matter recorded using the ink composition according to any one of claims 1 to 7.