JP5620700B2 - Ink composition for ink jet recording, ink jet recording method, and printed matter - Google Patents

Description

  The present invention relates to an ink composition for ink jet recording, an ink jet recording method, and a printed matter.

As an image recording method for forming an image on a support based on an image data signal, there are an electrophotographic method, a sublimation type and melt type thermal transfer method, an ink jet method and the like. The ink jet method is an inexpensive apparatus and ejects ink only to a required image portion to form an image directly on a support. Therefore, the ink composition can be used efficiently, and the running cost is low. Furthermore, there is little noise and it is excellent as an image recording method.
Specific examples of conventional ink compositions include the ink compositions described in Patent Documents 1 and 2.

JP 2001-207098 A JP 2004-067991 A

  An object of the present invention is an ink composition for ink jet recording that provides an image having excellent curability, adhesion, flexibility, and gloss, an ink jet recording method using the ink composition for ink jet recording, and Is to provide prints.

The above problems have been solved by the means described below.
<1> (Component A) Photopolymerization initiator, (Component B) Epoxy (meth) acrylate oligomer is 1 to 10% by weight based on the total weight of the ink composition, (Component C) represented by formula (C-1) The monofunctional monomer to be used is 10 to 30% by weight based on the total weight of the ink composition, and (Component D) the monofunctional monomer other than the component C is 5 to 70% by weight based on the total weight of the ink composition. An ink composition for ink jet recording, comprising:

（式（Ｃ−１）中、Ｒ¹は水素原子又はメチル基を表し、Ｘは、単結合、アルキレン基、オキシアルキレン基若しくは前記オキシアルキレン基を２以上組み合わせた基、エステル結合、又は、これらを２以上組み合わせた基を表し、Ｒ²及びＲ³は、それぞれ独立に、水素原子又はアルキル基を表し、Ｒ⁴〜Ｒ⁸は、それぞれ独立に、水素原子、アルキル基、アルコキシ基、アミノ基、又は、アミノアルキル基を表し、Ｒ⁴〜Ｒ⁸のうち少なくとも１つが水素原子であり、Ｒ⁴〜Ｒ⁸のうちいずれか２以上が結合して環状構造を形成してもよい。）

(In formula (C-1), R ¹ represents a hydrogen atom or a methyl group, and X is a single bond, an alkylene group, an oxyalkylene group or a group in which two or more of the above oxyalkylene groups are combined, an ester bond, or these R ² and R ³ each independently represents a hydrogen atom or an alkyl group, and R ^{4 to} R ⁸ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group. Or an aminoalkyl group, at least one of R ^{4 to} R ⁸ may be a hydrogen atom, and any two or more of R ^{4 to} R ⁸ may be bonded to form a cyclic structure.)

  <2> The ink composition according to <1>, wherein the component C is a compound represented by the formula (C-2);

（式（Ｃ−２）中、Ｒ¹は水素原子又はメチル基を表し、Ｘは、単結合、アルキレン基、オキシアルキレン基若しくは前記オキシアルキレン基を２以上組み合わせた基、エステル結合、又は、これらを２以上組み合わせた基を表す。）

(In the formula (C-2), R ¹ represents a hydrogen atom or a methyl group, and X is a single bond, an alkylene group, an oxyalkylene group or a group in which two or more of the above oxyalkylene groups are combined, an ester bond, or these Represents a group in which two or more are combined.)

<3> The ink composition according to <1> or <2>, which contains a compound represented by formula (D-1) or formula (D-2) as component D,

（式（Ｄ−１）及び式（Ｄ−２）中、Ｒ¹は水素原子、ハロゲン原子、又は、炭素数１〜４のアルキル基を表し、Ｘ¹は二価の連結基を表し、Ｒ²は置換基を表し、ｒは０〜５の整数を表し、ｑは環状炭化水素構造を表し、前記環状炭化水素構造として炭化水素結合以外にカルボニル結合（−Ｃ（Ｏ）−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）を含んでいてもよく、ｒ個存在するＲ²はそれぞれ同じであっても、異なっていてもよく、また、ノルボルナン骨格中の一炭素原子をエーテル結合（−Ｏ−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）で置換してもよい。）

(In Formula (D-1) and Formula (D-2), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, and R ² represents a substituent, r represents an integer of 0 to 5, q represents a cyclic hydrocarbon structure, and the cyclic hydrocarbon structure includes a carbonyl bond (—C (O) —) and / or other than a hydrocarbon bond. It may contain an ester bond (—C (O) O—), and r ² R ^{2 s} may be the same or different from each other, and one carbon atom in the norbornane skeleton is bonded to an ether bond. (It may be substituted with (—O—) and / or an ester bond (—C (O) O—).)

<4> As the component D, at least selected from the group consisting of isobornyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentanyl (meth) acrylate The ink composition according to any one of <1> to <3>, comprising one compound;
<5> The ink composition according to any one of <1> to <4>, further including a pigment,
<6> The ink composition according to any one of <1> to <5>, further including 1 to 10% by weight of a urethane (meth) acrylate oligomer based on a total weight of the ink composition,
<7> The ink composition according to any one of <1> to <6>, wherein the component A includes an acylphosphine compound and an aromatic ketone.
<8> An image forming step of forming an image on a support by discharging the ink composition according to any one of <1> to <7> by an inkjet method, and irradiating the obtained image with active radiation A curing step of curing the ink composition to obtain a printed material having a cured image on the support,
<9> maximum illumination of the actinic radiation is less than 1,000 mW / cm ² or more 3,000 mW / cm ^2, the ink jet recording method according to <8>,
<10> A printed matter produced by the inkjet recording method according to <8> or <9>.

  INDUSTRIAL APPLICABILITY According to the present invention, an ink composition for ink jet recording capable of obtaining an image having excellent curability, adhesion, flexibility and glossiness, an ink jet recording method using the ink composition for ink jet recording, and a printed matter. Could be provided.

I. Ink composition for ink jet recording The ink composition for ink jet recording of the present invention (hereinafter also referred to as “ink composition”) is an ink containing (Component A) a photopolymerization initiator and (Component B) an epoxy (meth) acrylate oligomer. 1 to 10% by weight based on the total weight of the composition, (Component C) 10 to 30% by weight of the monofunctional monomer represented by the formula (C-1) based on the total weight of the ink composition, and ( Component D) A monofunctional monomer other than the component C is contained in an amount of 5 to 70% by weight based on the total weight of the ink composition. In the specification, the description of “A to B” representing a numerical range is synonymous with “A or more and B or less” unless otherwise specified. Moreover, description of "(meth) acrylate" etc. is synonymous with "methacrylate and / or acrylate" etc.

（式（Ｃ−１）中、Ｒ¹は水素原子又はメチル基を表し、Ｘは、単結合、アルキレン基、オキシアルキレン基若しくは前記オキシアルキレン基を２以上組み合わせた基、エステル結合、又は、これらを２以上組み合わせた基を表し、Ｒ²及びＲ³は、それぞれ独立に、水素原子又はアルキル基を表し、Ｒ⁴〜Ｒ⁸は、それぞれ独立に、水素原子、アルキル基、アルコキシ基、アミノ基、又は、アミノアルキル基を表し、Ｒ⁴〜Ｒ⁸のうち少なくとも１つが水素原子であり、Ｒ⁴〜Ｒ⁸のうちいずれか２以上が結合して環状構造を形成してもよい。）

(In formula (C-1), R ¹ represents a hydrogen atom or a methyl group, and X is a single bond, an alkylene group, an oxyalkylene group or a group in which two or more of the above oxyalkylene groups are combined, an ester bond, or these R ² and R ³ each independently represents a hydrogen atom or an alkyl group, and R ^{4 to} R ⁸ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group. Or an aminoalkyl group, at least one of R ^{4 to} R ⁸ may be a hydrogen atom, and any two or more of R ^{4 to} R ⁸ may be bonded to form a cyclic structure.)

  The ink composition of the present invention is an oil-based ink composition that can be cured by actinic radiation. “Actinic radiation” is radiation that can give energy to generate an initial species in the ink composition by irradiation, and includes α rays, γ rays, X rays, ultraviolet rays, visible rays, electron rays, and the like. Of these, ultraviolet rays and electron beams are preferable from the viewpoint of curing sensitivity and device availability, and ultraviolet rays are more preferable.

The ink composition of the present invention not only excels in adhesion, curability and flexibility, but can form an image having a glossy feeling within a specific illuminance range.
Hereinafter, each component will be described.

(Component A) Photopolymerization Initiator The ink composition of the present invention contains (Component A) a photopolymerization initiator (hereinafter also referred to as “polymerization initiator”). The polymerization initiator is a compound that absorbs external energy such as the actinic radiation to generate a polymerization initiating species.
Examples of the polymerization initiator that can be used in the present invention include aromatic ketones, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, Examples thereof include azinium compounds, metallocene compounds, active ester compounds, and compounds having a carbon halogen bond. Specific examples of these polymerization initiators include polymerization initiators described in JP 2008-208190 A and JP 2009-096985 A. A polymerization initiator may be used individually by 1 type, and may use 2 or more types together.

  Of these, acylphosphine compounds and aromatic ketones are preferred as the polymerization initiator. Preferred aromatic ketones include α-hydroxyacetophenone compounds and thioxanthone compounds.

<Acylphosphine compound>
Preferred examples of the acylphosphine compound include the acylphosphine oxide compounds described in paragraphs 0080 to 0098 of JP-A-2009-096985, and among them, the formula (A-1) or the formula (A-2) is included in the structure of the compound. What has the structure represented by these is preferable.

  In particular, as the acylphosphine oxide compound, those having a chemical structure of the formula (A-3) or the formula (A-4) are preferable.

（式（Ａ−３）中、Ｒ⁶、Ｒ⁷、Ｒ⁸はメチル基又はエチル基を置換基として有していてもよい芳香族炭化水素基を表す。）

(In formula (A-3), R ⁶ , R ⁷ and R ⁸ represent an aromatic hydrocarbon group which may have a methyl group or an ethyl group as a substituent.)

As a monoacylphosphine oxide compound represented by the formula (A-3), R ^{6 to} R ⁸ are preferably phenyl groups which may have a methyl group as a substituent, and R ⁷ and R ⁸ Is more preferably a phenyl group, and R ⁸ is more preferably a phenyl group having 1 to 3 methyl groups.
Among them, as the monoacylphosphine oxide compound represented by the formula (A-3), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Darocur TPO: manufactured by Ciba Specialty Chemicals, Lucirin TPO: manufactured by BASF) Is preferred.

（式（Ａ−４）中、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹はメチル基又はエチル基を置換基として有していてもよい芳香族炭化水素基を表す。）

(In the formula (A-4), R ⁹ , R ¹⁰ and R ¹¹ represent an aromatic hydrocarbon group which may have a methyl group or an ethyl group as a substituent.)

In the present invention, as the bisacylphosphine oxide compound represented by the formula (A-4), R ^{9 to} R ¹¹ are preferably a phenyl group which may have a methyl group as a substituent, More preferably, R ¹¹ is a phenyl group, and R ⁹ and R ¹¹ are phenyl groups having 1 to 3 methyl groups.
Of these, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (IRGACURE819, manufactured by Ciba Specialty Chemicals) is preferable as the bisacylphosphine oxide compound represented by the formula (A-4).

<Α-Hydroxyacetophenone compound>
The α-hydroxyacetophenone compound is preferably a compound represented by the formula (A-5).

（式（Ａ−５）中、Ｒ¹は水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、又は、炭素数１〜１０のアルコキシ基、炭素数１〜１０のアルキルチオ基、アミノ基（一置換及び二置換の場合を含む。）、ヒドロキシ基、カルボキシ基（カルボアルコキシ基を含む。）、炭素数１〜１０のヒドロキシアルコキシ基を表し、Ｒ²、Ｒ³は互いに独立して、水素原子、又は、炭素数１〜１０のアルキル基を表し、Ｒ²とＲ³とは結合して炭素数４〜８の環を形成していてもよい。）

(In the formula (A-5), R ¹ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an amino group ( Mono- and di-substituted)), a hydroxy group, a carboxy group (including a carboalkoxy group), a hydroxyalkoxy group having 1 to 10 carbon atoms, and R ² and R ³ are each independently hydrogen. An atom or an alkyl group having 1 to 10 carbon atoms, and R ² and R ³ may be bonded to form a ring having 4 to 8 carbon atoms.)

Examples of α-hydroxyacetophenones include 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173), 2-hydroxy-2-methyl-1-phenylbutan-1-one, 1- (4-methylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-isopropylphenyl) -2-methylpropan-1-one, 1- (4-butylphenyl) -2-hydroxy 2-methylpropan-1-one, 2-hydroxy-2-methyl-1- (4-octylphenyl) propan-1-one, 1- (4-dodecylphenyl) -2-methylpropan-1-one, 1- (4-methoxyphenyl) -2-methylpropan-1-one, 1- (4-methylthiophenyl) -2-methylpropan-1-one, 1- 4-chlorophenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-bromophenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1- (4-hydroxy Phenyl) -2-methylpropan-1-one, 1- (4-dimethylaminophenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-carboethoxyphenyl) -2-hydroxy-2 -Methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone (IRGACURE 184), 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one ( IRGACURE 2959).
Commercially available α-hydroxyacetophenone compounds available from Ciba Specialty Chemicals under the trade names Irgacure 184 (IRGACURE 184), Darocur 1173 (DAROCUR 1173), Irgacure 127 (IRGACURE 127), Irgacure 2959 (IRGACURE 2959) Any polymerization initiator can also be used.

<Thioxanthone compound>
The thioxanthone compound is preferably a compound represented by the formula (A-6).

（式（Ａ−６）中、Ｒ¹〜Ｒ⁸はそれぞれ独立に、水素原子、アルキル基、ハロゲン原子、ヒドロキシ基、シアノ基、ニトロ基、アミノ基、アルキルチオ基、アルキルアミノ基（一置換及び二置換の場合を含む。）、アルコキシ基、アルコキシカルボニル基、アシルオキシ基、アシル基、カルボキシ基又はスルホ基を表す。）

(In formula (A-6), R ^{1 to} R ⁸ are each independently a hydrogen atom, an alkyl group, a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, an alkylthio group, an alkylamino group (monosubstituted and Including a case of disubstitution.), An alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxy group or a sulfo group.

1-20 are preferable, as for carbon number of the alkyl part in the said alkyl group, alkylthio group, alkylamino group, alkoxy group, alkoxycarbonyl group, acyloxy group, and an acyl group, 1-8 are more preferable, and 1-4 are preferable. Further preferred.
Two adjacent R ^{1 to} R ⁸ may be connected to each other to form a ring. Examples of the ring structure in the case where these form a ring include a 5- or 6-membered aliphatic ring, an aromatic ring, etc., and may be a heterocyclic ring containing an element other than a carbon atom. The rings may be further combined to form a binuclear ring, for example, a condensed ring. These ring structures may further have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, an alkylthio group, an alkylamino group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxy group, and a sulfo group. N, O, and S can be mentioned as an example of a hetero atom in case the formed ring structure is a heterocyclic ring.

Examples of the thioxanthone compound include thioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-dodecylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 1-methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3- (2-methoxyethoxycarbonyl) thioxanthone, 4-butoxycarbonylthioxanthone, 3-butoxycarbonyl-7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-ethoxycarbonyl-3-chlorothioxanthone, 1-ethoxycarbonyl-3 -Ethoxythioxanthone, 1-ethoxycarbonyl-3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfylthioxanthone, , 4-di [2- (2-methoxyethoxy) ethoxycarbonyl] thioxanthone, 1-ethoxycarbonyl-3- (1-methyl-1-morpholinoethyl) thioxanthone, 2-methyl-6-dimethoxymethylthioxanthone, 2-methyl -6- (1,1-dimethoxybenzyl) thioxanthone, 2-morpholinomethylthioxanthone, 2-methyl-6-morpholinomethylthioxanthone, n-allylthioxanthone-3,4-dicarboximide, n-octylthioxanthone-3,4 -Dicarboximide, N- (1,1,3,3-tetramethylbutyl) thioxanthone-3,4-dicarboximide, 1-phenoxythioxanthone, 6-ethoxycarbonyl-2-methoxythioxanthone, 6-ethoxycarbonyl- 2-Methylthioki Thioxanthone-2-polyethylene glycol ester, 2-hydroxy-3- (3,4-dimethyl-9-oxo-9H-thioxanthone-2-yloxy) -N, N, N-trimethyl-1-propanaminium chloride Can be illustrated.
Among these, 2-isopropylthioxanthone and 4-isopropylthioxanthone are more preferable from the viewpoint of availability and curability.

In the present invention, it is preferable to use an acylphosphine compound and an aromatic ketone in combination from the viewpoint of curability.
As the acylphosphine compound, a monoacylphosphine oxide compound is more preferable.
As the aromatic ketones, α-hydroxyacetophenone compounds and thioxanthone compounds are more preferable.
Therefore, it is more preferable to use a monoacylphosphine oxide compound, an α-hydroxyacetophenone compound, and a thioxanthone compound in combination.

In the present invention, the total amount of the polymerization initiator used is preferably 1 to 25% by weight, more preferably 1.2 to 18% by weight with respect to the total weight of the ink composition from the viewpoint of curability. 5 to 15% by weight is more preferable.
Of the total amount of the polymerization initiator, 50% by weight or more is preferably an acylphosphine oxide compound.
Moreover, when using a sensitizer, the total usage-amount of a polymerization initiator is a weight ratio of a polymerization initiator: sensitizer with respect to a sensitizer, Preferably it is 200: 1-1: 200, More preferably It is in the range of 50: 1 to 1:50, more preferably 20: 1 to 1: 5.

(Component B) Epoxy (meth) acrylate oligomer The ink composition of the present invention contains (Component B) an epoxy (meth) acrylate oligomer in an amount of 1 to 10% by weight based on the total weight of the ink composition.

  From the viewpoint of curability and flexibility, the weight average molecular weight of the epoxy (meth) acrylate oligomer is preferably 330 to 1,500, and more preferably 500 to 850.

The epoxy (meth) acrylate oligomer preferably has at least one (meth) acryloyloxy group as a functional group in the molecule, more preferably 2 to 4, more preferably two.
The (meth) acryloyloxy group is preferably acryloyloxy from the viewpoint of curability.
Component B preferably has no polymerizable ethylenically unsaturated bond other than the (meth) acryloyloxy group.

The viscosity of the epoxy (meth) acrylate oligomer at 25 ° C. is preferably 500 to 50,000 mPa · s, more preferably 5,000 to 40,000 mPa · s so that the polarity and viscosity of the ink can be adjusted with a small addition amount. More preferably, it is 10,000 to 30,000 mPa · s.
The viscosity of the epoxy (meth) acrylate oligomer is stabilized by rotating the rotor for 2 minutes at each temperature (25 ° C., 40 ° C., 60 ° C.) using an RE80 viscometer (manufactured by Toki Sangyo Co., Ltd.). Measured after. The method for measuring the viscosity at 25 ° C. is not particularly limited, but is preferably a measuring method based on JIS Z8803. Moreover, as a viscosity measuring apparatus, it is preferable to use a rotational viscometer, and it is preferable to use a B type or E type rotational viscometer.
If the viscosity is too high to be measured at 25 ° C or 40 ° C, the viscosity is measured at 60 ° C. The viscosity at 60 ° C. is preferably 1,000 to 10,000 mPa · s, more preferably 2,000 to 8,000 mPa · s, and still more preferably 3,000 to 6,000 mPa · s.

The glass transition temperature of the epoxy (meth) acrylate oligomer is preferably 70 ° C. or lower, more preferably 60 ° C. or lower, from the viewpoint of balance between curability and flexibility.
In addition, glass transition temperature (Tg) can be calculated | required from the main body maximum peak measured using the differential scanning calorimeter (Perkin-Elmer company make: DSC-7) based on ASTMD3418-8, for example. The temperature correction of the detection part of this apparatus (DSC-7) uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. The sample used was an aluminum pan, and an empty pan was set as a control. The temperature was raised at a rate of 10 ° C / min, held at 150 ° C for 5 minutes, cooled from 150 ° C to 0 ° C at -10 ° C / min using liquid nitrogen, held at 0 ° C for 5 minutes, and again 0 The onset temperature analyzed from the endothermic curve during the second temperature rise obtained by raising the temperature from 10 ° C. to 150 at 10 ° C./min was defined as Tg.

  Specific examples of the epoxy (meth) acrylate oligomer include Laromar LR8765, LR8986, LR8713, and EA81 manufactured by BASF; Ebecryl 3420, 3500, 3701, 3703, and 3708 manufactured by Daicel-Cytec.

The content of the epoxy (meth) acrylate oligomer is 1 to 10% by weight with respect to the total weight of the ink composition. If it is less than 1% by weight, curability and gloss may be lowered. On the other hand, if it exceeds 10% by weight, the glossiness may decrease.
In the present invention, since excellent adhesion is obtained and an image having high gloss is obtained, the content of the epoxy (meth) acrylate oligomer is preferably 2 to 10% by weight, more preferably 5 to 8% by weight. .

(Component C) Compound Represented by Formula (C-1) The ink composition of the present invention comprises (Component C) a compound represented by Formula (C-1) in an amount of 10 to 10 based on the total weight of the ink composition. Contains 30% by weight.

（式（Ｃ−１）中、Ｒ¹は水素原子又はメチル基を表し、Ｘは、単結合、アルキレン基、オキシアルキレン基若しくは前記オキシアルキレン基を２以上組み合わせた基、エステル結合、又は、これらを２以上組み合わせた基を表し、Ｒ²及びＲ³は、それぞれ独立に、水素原子又はアルキル基を表し、Ｒ⁴〜Ｒ⁸は、それぞれ独立に、水素原子、アルキル基、アルコキシ基、アミノ基、又は、アミノアルキル基を表し、Ｒ⁴〜Ｒ⁸のうち少なくとも１つが水素原子であり、Ｒ⁴〜Ｒ⁸のうちいずれか２以上が結合して環状構造を形成してもよい。）

(In formula (C-1), R ¹ represents a hydrogen atom or a methyl group, and X is a single bond, an alkylene group, an oxyalkylene group or a group in which two or more of the above oxyalkylene groups are combined, an ester bond, or these R ² and R ³ each independently represents a hydrogen atom or an alkyl group, and R ^{4 to} R ⁸ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group. Or an aminoalkyl group, at least one of R ^{4 to} R ⁸ may be a hydrogen atom, and any two or more of R ^{4 to} R ⁸ may be bonded to form a cyclic structure.)

In formula (C-1), R ¹ represents a hydrogen atom or a methyl group, and preferably a hydrogen atom.

X represents a single bond, an alkylene group, an oxyalkylene group, a group in which two or more of the above oxyalkylene groups are combined, an ester bond, or a group in which two or more of these are combined.
As said alkylene group, a C1-C10 alkylene group is preferable and a C1-C8 alkylene group is more preferable.
An oxyalkylene group or a group formed by combining two or more oxyalkylene groups is a group in which the alkylene group side is bonded to the oxygen atom of the (meth) acryloyloxy group in formula (C-1). The alkylene group contained in the oxyalkylene group is preferably a linear or branched alkylene group having 1 to 5 carbon atoms, more preferably a linear or branched alkylene group having 2 or 3 carbon atoms, and an isopropylene group. Further preferred. When two or more oxyalkylene groups are combined, it is preferably 10 or less, and more preferably 5 or less.
When X contains an ester bond, X is preferably a group in which the alkylene group and the ester bond are combined.

R ² and R ³ each independently represent a hydrogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group.

R ^{4 to} R ⁸ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or an aminoalkyl group.
The alkyl group is preferably a linear or branched alkyl group having 1 to 10 carbon atoms.
The alkoxy group is preferably a linear or branched alkoxy group having 1 to 5 carbon atoms, and more preferably a methoxy group.
The amino group includes an amino group, a monoalkylamino group, and a dialkylamino group, and the alkyl group is preferably a linear or branched alkyl group having 1 to 3 carbon atoms. The amino group is preferably a dimethylamino group, a diethylamino group, or a diisopropylamino group.
The amino group contained in the aminoalkyl group is the same as the amino group. That is, the aminoalkyl group includes a monoalkylaminoalkyl group and a dialkylaminoalkyl group. The alkyl group portion excluding the amino group of the aminoalkyl group is preferably an alkyl having 1 to 3 carbon atoms. The aminoalkyl group is preferably a dimethylaminomethyl group, a diethylaminomethyl group, or a diisopropylaminomethyl group.

At least one of R ^{4 to} R ⁸ is a hydrogen atom. When at least one of R ^{4 to} R ⁸ is a hydrogen atom, an ink composition having excellent curability can be obtained.

Any two or more of R ^{4 to} R ⁸ may be bonded to form a cyclic structure. When forming a ring, it is preferable that R < ⁴ > -R < ⁸ > which forms a ring is an alkyl group. A ring formed by combining R ⁴ or R ⁵ and any one of R ^{6 to} R ⁸ is preferred, more preferably a cyclic ether group having 4 to 6 ring members, more preferably a cyclic ether having 5 ring members. More preferably it forms a group, i.e. a tetrahydrofurfuryl group.

  Component C is preferably a compound having a tetrahydrofurfuryl group, and more preferably a compound represented by formula (C-2), since it is excellent in curability.

（式（Ｃ−２）中、Ｒ¹は水素原子又はメチル基を表し、Ｘは、単結合、アルキレン基、オキシアルキレン基若しくは前記オキシアルキレン基を２以上組み合わせた基、エステル結合、又は、これらを２以上組み合わせた基を表す。）

(In the formula (C-2), R ¹ represents a hydrogen atom or a methyl group, and X is a single bond, an alkylene group, an oxyalkylene group or a group in which two or more of the above oxyalkylene groups are combined, an ester bond, or these Represents a group in which two or more are combined.)

  X is the same as X in formula (C-1), and the preferred range is also the same.

  Specific examples of component C are illustrated below, but the present invention is not limited to these specific examples. In the exemplified compounds, R represents a hydrogen atom or a methyl group.

The content of Component C is 10 to 30% by weight with respect to the total weight of the ink composition. If the content of Component C is less than 10% by weight, curability and gloss may be lowered. On the other hand, if the content of Component C exceeds 30% by weight, the glossiness of the obtained image may be lowered.
The content of Component C is preferably 12 to 28% by weight, more preferably 15 to 25% by weight, based on the total weight of the ink composition, from the viewpoint of balance between curability, adhesion, and gloss.

(Component D) Monofunctional monomer other than Component C The ink composition of the present invention contains (Component D) a monofunctional monomer other than Component C in an amount of 5 to 70% by weight based on the total weight of the ink composition.

  Examples of component D include monofunctional radical polymerizable monomers having an aliphatic cyclic structure and aromatic monofunctional radical polymerizable monomers described in JP-A-2009-096985. The monofunctional radically polymerizable monomer having an aliphatic cyclic structure is more preferably a compound having a norbornane skeleton represented by the formula (D-1) or the formula (D-2).

（式（Ｄ−１）及び式（Ｄ−２）中、Ｒ¹は水素原子、ハロゲン原子、又は、炭素数１〜４のアルキル基を表し、Ｘ¹は二価の連結基を表し、Ｒ²は置換基を表し、ｒは０〜５の整数を表し、ｑは環状炭化水素構造を表し、前記環状炭化水素構造として炭化水素結合以外にカルボニル結合（−Ｃ（Ｏ）−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）を含んでいてもよく、ｒ個存在するＲ²はそれぞれ同じであっても、異なっていてもよく、また、ノルボルナン骨格中の一炭素原子をエーテル結合（−Ｏ−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）で置換してもよい。）

(In Formula (D-1) and Formula (D-2), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, and R ² represents a substituent, r represents an integer of 0 to 5, q represents a cyclic hydrocarbon structure, and the cyclic hydrocarbon structure includes a carbonyl bond (—C (O) —) and / or other than a hydrocarbon bond. It may contain an ester bond (—C (O) O—), and r ² R ^{2 s} may be the same or different from each other, and one carbon atom in the norbornane skeleton is bonded to an ether bond. (It may be substituted with (—O—) and / or an ester bond (—C (O) O—).)

In formulas (D-1) and (D-2), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, and an ether group. (—O—), ester group (—C (O) O— or —OC (O) —), amide group (—C (O) NR′—), carbonyl group (—C (O) —), imino It is preferably a group (—NR′—), an optionally substituted alkylene group having 1 to 15 carbon atoms, or a divalent group in which two or more thereof are combined. R ′ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R ² represents a substituent, r represents an integer of 0 to 5, q represents a cyclic hydrocarbon structure, and the cyclic hydrocarbon structure includes a carbonyl bond (—C (O) —) and / or a hydrocarbon bond in addition to the hydrocarbon bond. Alternatively, an ester bond (—C (O) O—) may be contained, and r ² R ^{2 s} may be the same or different from each other, and one carbon atom in the norbornane skeleton is substituted with an ether. A bond (—O—) and / or an ester bond (—C (O) O—) may be substituted.
In Formula (D-1) and Formula (D-2), R ¹ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group.

Wherein (D-1) and Formula (D-2), an end portion which binds to a vinyl group of X ¹ is preferably an ester group or in which the carbonyl carbon and a vinyl group X ¹ binds is an amide group, More preferably, it is an ester bond. In particular, it is preferable to have a structure of H ₂ C═C (R ¹ ) —C (O) O—. In that case, the other part of X ¹ bonded to the norbornane skeleton may be a single bond or may be arbitrarily selected from the above-mentioned groups.
The vinyl moiety containing R ¹ and X ¹ (H ₂ C═C (R ¹ ) —X ¹ —) can be attached at any position on the alicyclic hydrocarbon structure. The term “on the alicyclic hydrocarbon structure” refers to the norbornane structure in the formula (D-1) and the formula (D-2) and the cyclic hydrocarbon structure including q in the formula (D-2).
Further, from the viewpoint of improving the affinity with the colorant, the end bonded to the alicyclic hydrocarbon structure of X ¹ is preferably an oxygen atom, more preferably an etheric oxygen atom, X ¹ in formula (D-1) and formula (D-2) is more preferably —C (O) O (CH ₂ CH ₂ O) _p — (p represents 1 or 2).
That is, X ¹ is preferably * —C (O) O (LO) _q — or * —C (O) NH (LO) _q —. Here, * indicates the bonding position to X ¹ and vinyl group of formula (A2), q is an integer of 0, L represents an alkylene group having 2 to 4 carbon atoms. Among these, X ¹ is preferably * —C (O) O (LO) _q —, q is preferably an integer of 0 to 4, more preferably an integer of 0 to 2, More preferably, it is 1 or 2. (LO) _q is preferably an ethylene oxide chain or a propylene oxide chain.

R ² in Formula (D-1) and Formula (D-2) each independently represents a substituent, and can be bonded at any position on the alicyclic hydrocarbon structure. Further, r R ^{2 s} may be the same or different.
The R ² R ² may be each independently a monovalent or polyvalent substituent, and as a monovalent substituent, a hydroxy group, a substituted or unsubstituted amino group, a thiol group, a siloxane group, and a substituted group It is preferably a hydrocarbon group or heterocyclic group having a total carbon number of 30 or less, which may have a group, or an oxy group (═O) as a divalent substituent.
The substitution number r of R ² represents an integer of 0 to 5.

  Q in the formula (D-2) represents a cyclic hydrocarbon structure, and both ends thereof may be substituted at any position of the norbornane skeleton, and may be a monocyclic structure or a polycyclic structure. In addition to the hydrocarbon bond, the cyclic hydrocarbon structure may contain a carbonyl bond (—C (O) —) and / or an ester bond (—C (O) O—).

  The monomer represented by the formula (D-2) is preferably a monomer represented by the formula (D-3) or the formula (D-4). The unsaturated bond in the cyclic hydrocarbon structure in formula (D-4) has low radical polymerizability, and in the present invention, the compound represented by formula (D-4) is a monofunctional radically polymerizable monomer. It shall be.

（式（Ｄ−３）及び式（Ｄ−４）中、Ｒ¹は水素原子、ハロゲン原子、又は、炭素数１〜４のアルキル基を表し、Ｘ¹は二価の連結基を表し、Ｒ³及びＲ⁴はそれぞれ独立に置換基を表し、ｓ及びｔはそれぞれ独立に０〜５の整数を表し、また、ｓ個存在するＲ³及びｔ個存在するＲ⁴はそれぞれ同じであっても、異なっていてもよい。）

(In Formula (D-3) and Formula (D-4), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, R ³ and R ⁴ each independently represents a substituent, s and t each independently represents an integer of 0 to 5, and s R ³ and t R ⁴ may be the same. , May be different.)

R ¹ and X ¹ in Formula (D-3) or Formula (D-4) has the same meaning as R ¹ and X ¹ in Formula (D-1), and preferred ranges are also the same.
The vinyl moiety containing R ¹ and X ¹ in the formula (D-3) or the formula (D-4) is on each alicyclic hydrocarbon structure shown below in the formula (D-3) or the formula (D-4). Can be combined at any position.

R ³ and R ⁴ in Formula (D-3) or Formula (D-4) each independently represent a substituent, and each of the above alicyclic hydrocarbon structures in Formula (D-3) or Formula (D-4) Can be combined at any position above. The substituent in R < ³ > and R < ⁴ > is synonymous with the substituent in R < ² > of Formula (D-1), and its preferable range is also the same.
In Formula (D-3) or Formula (D-4), s and t each independently represent an integer of 0 to 5, and s R ³ and t R ⁴ are the same. May be different.

Specific examples of the monomers represented by formula (D-1) and formula (D-2) include the monomers described in paragraphs 0042 to 0046 of JP-A-2009-096985.
In the present invention, at least one compound selected from the group consisting of isobornyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentanyl (meth) acrylate Are preferred, and compounds corresponding to formula (D-2) and formula (D-3) are more preferred, selected from the group consisting of dicyclopentenyloxyethyl acrylate, dicyclopentenyl acrylate, and dicyclopentanyl acrylate. More preferred is at least one compound.

  Examples of component D include aromatic monofunctional radically polymerizable monomers described in paragraphs 0048 to 0063 of JP-A-2009-096985. Especially, as an aromatic monofunctional radically polymerizable monomer, the compound represented by Formula (D-5) is preferable.

（式（Ｄ−５）中、Ｒ¹は水素原子、又は、メチル基を表し、Ｘ¹は二価の連結基を表し、Ｒ⁵は置換基を表し、ｕは０〜５の整数を表し、また、ｕ個存在するＲ⁵はそれぞれ同じであっても、異なっていてもよい。）

(In Formula (D-5), R ¹ represents a hydrogen atom or a methyl group, X ¹ represents a divalent linking group, R ⁵ represents a substituent, and u represents an integer of 0 to 5. And u ⁵ R ^{5 s} may be the same or different.)

In formula (D-5), R ¹ is preferably a hydrogen atom.
X ¹ has the same meaning as X ¹ in the formula (D-1), and a preferred range is also the same.
u ⁵ R ^{5 s} are each independently a hydroxy group, a substituted or unsubstituted amino group, a thiol group, a siloxane group, or a hydrocarbon group having a total carbon number of 30 or less which may further have a substituent. Or it is preferable that it is a heterocyclic group.
u represents an integer of 0 to 5, and is preferably 0.
In addition, although the benzene ring in Formula (D-5) may be an aromatic heterocyclic ring containing hetero atoms, such as O, N, and S, it is preferable that a hetero atom is not included.
In the present invention, preferred examples of the compound represented by formula (D-5) include 2-phenoxyethyl acrylate.

  In the present invention, from the viewpoint of excellent curability, adhesion, and glossiness, the monofunctional radical polymerizable monomer having the aliphatic cyclic structure preferably accounts for 45% by weight or more of the entire component D. As the monofunctional radically polymerizable monomer having an aliphatic cyclic structure, compounds represented by formula (D-1) and formula (D-2) are preferable, and a compound represented by formula (D-2) is more preferable. Preferably, the compound represented by the formula (D-3) and the compound represented by the formula (D-4) are more preferably used in combination.

The ink composition of the present invention contains 5 to 70% by weight of component D based on the total weight of the ink composition. When the content of Component D is less than 5% by weight, glossiness and flexibility may be lowered. Moreover, when content of the component D exceeds 70 weight%, glossiness and adhesiveness may fall.
The content of Component D is preferably 5 to 60% by weight, more preferably 10 to 55% by weight, and further preferably 15 to 50% by weight based on the total weight of the ink composition from the viewpoints of glossiness and flexibility. preferable.

(Component E) Oligomer other than Component B The ink composition of the present invention preferably contains an oligomer other than (Component E) Component B.
When the ink composition of the present invention contains Component B and an oligomer other than Component B, images formed on various recording media have excellent adhesion and gloss, ink bleeding, and line width. The occurrence of non-uniformity and color unevenness can be suppressed.
In addition, by using the ink composition of the present invention, even when single color ink or multicolor ink is deposited and deposited, a uniform dot diameter and line width without expanding the dot diameter and line width are maintained, and the image form is maintained. Regardless of the detail, it can be recorded with high density and high reproducibility.

  The oligomer is a polymer in which a finite number (5 to 100) of monomers are bonded, and a known compound called an oligomer can be arbitrarily selected. In the present invention, the weight average molecular weight is preferably 350. A polymer of ~ 2,800, more preferably 900-1,200 is selected.

The viscosity of the oligomer at 25 ° C. is preferably 1,000 to 500,000 mPa · s, more preferably 5,000 to 400,000 mPa · s so that the polarity and viscosity of the ink can be adjusted with a small addition amount. 000 to 100,000 mPa · s is more preferable.
If the viscosity is too high to be measured at 25 ° C or 40 ° C, the viscosity is measured at 60 ° C. The viscosity at 60 ° C. is preferably 1,000 to 10,000 mPa · s, more preferably 2,000 to 8,000 mPa · s, and still more preferably 3,000 to 6,000 mPa · s.
In addition, a viscosity can be measured with the measuring method similar to the measuring method of the viscosity in the component B.

  The glass transition temperature of the oligomer other than Component B is preferably 70 ° C. or lower, more preferably 60 ° C. or lower, from the viewpoints of curability and flexibility. In addition, a glass transition temperature (Tg) can be measured with the measuring method similar to the measuring method of the glass transition temperature in the component B.

As the oligomer other than Component B, those having a (meth) acryloyl group as a functional group are preferable.
In addition, the number of functional groups contained in the oligomer other than Component B is preferably 1 to 15, more preferably 2 to 6, more preferably 2 to 4, and particularly preferably 2 from the viewpoint of curability and adhesion.

  Examples of the oligomer in the present invention include olefins (ethylene oligomers, propylene oligomers butene oligomers, etc.), vinyls (styrene oligomers, vinyl alcohol oligomers, vinyl pyrrolidone oligomers (meth) acrylate oligomers, methacrylate oligomers, etc.), dienes (butadiene oligomers, Chloroprene rubber, pentadiene oligomer, etc.), ring-opening polymerization system (di-, tri-, tetraethylene glycol, polyethylene glycol, polyethylimine, etc.), polyaddition system (oligoester (meth) acrylate, polyamide oligomer, polyisocyanate oligomer) And addition condensation oligomers (phenol resin, amino resin, xylene resin, ketone resin, etc.). Of these, oligoester (meth) acrylates are preferred, and among them, urethane acrylics and polyester (meth) acrylates are more preferred, and urethane (meth) acrylates are ink compositions with excellent curability and adhesion. Is particularly preferred since The oligomers may be used in combination of a plurality of types in addition to a single type.

  Examples of urethane (meth) acrylates include aliphatic urethane (meth) acrylates and aromatic urethane (meth) acrylates. For details, refer to the oligomer handbook (supervised by Junji Yoshikawa, Chemical Daily).

  Examples of urethane (meth) acrylate oligomers include U-2PPA, U-4HA, U-6HA, U-6LPA, U-15HA, U-324A, UA-122P, UA5201, manufactured by Shin-Nakamura Chemical Co., Ltd. CN964A85, CN964, CN959, CN962, CN963J85, CN965, CN982B88, CN981, CN983, CN996, CN9002, CN9009, CN9010, CN9010, CN9110, CN9110, CN9110

  The oligomer content other than Component B is preferably 1 to 10% by weight, more preferably 2 to 8% by weight, more preferably 3 to 7%, based on the total weight of the ink composition, from the viewpoint of achieving both curability and adhesion. More preferred is weight percent.

(Component F) Multifunctional monomer In the present invention, an ethylenic group selected from the group consisting of a (meth) acrylate group, a (meth) acrylamide group, a vinyloxy group, and an N-vinyl group as the radical polymerizable monomer, if necessary. A polyfunctional monomer having two or more unsaturated groups can be used in combination. By containing a polyfunctional monomer, an image having high cured film strength can be obtained.
However, from the viewpoint of maintaining the adhesion of the base material (recording medium) of the cured film, the ratio of the polyfunctional monomer to the total weight of the ink composition is preferably 50% by weight or less, more preferably 40% by weight or less. preferable.

  Polyfunctional monomers include 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, bis (4-acryloxypolyethoxyphenyl) propane, neopentyl glycol di ( (Meth) acrylate, ethoxylated neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, hydroxypivalate neopentyl glycol diacrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) ) Acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene oxide (EO) modified pentaerythritol tri (meth) acrylate, propylene Oxide (PO) modified pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, EO modified pentaerythritol tetra (meth) acrylate, PO modified pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate tolylene Isocyanate urethane prepolymer, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate Urethane prepolymer, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate urethane prepolymer, dipentaerythritol tetra (meth) acrylate, EO-modified dipentaerythritol tetra (meth) acrylate, PO-modified dipentaerythritol tetra (meth) acrylate , Trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, EO modified tetramethylol methane tetra (meth) acrylate, PO modified tetramethylol methane tetra (meth) acrylate, tetra PO addition of methylol methane tri (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, modified glycerin tri (meth) acrylate, modified bisphenol A di (meth) acrylate, bisphenol A Di (meth) acrylate, EO adduct of bisphenol A di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, 2,2-bis (4- (meth) Acryloxypolyethoxyphenyl) propane, diallyl phthalate, triallyl trimellitate and the like.

Furthermore, you may use a vinyl ether compound as a radically polymerizable compound.
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 trivinyl ether compounds such as methylolpropane trivinyl ether, ethylene glycol monovinyl ether, triethylene glycol monovinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, hydroxyethyl monovinyl ether, hydroxybutyl vinyl ether, Mud carboxymethyl monovinyl ether, 2-ethylhexyl vinyl ether, n- propyl vinyl ether, isopropyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, octadecyl vinyl ether, monovinyl ether compounds, and the like and the like.

(Component G) Colorant The ink composition of the present invention may contain a colorant in order to improve the visibility of the formed image portion. A clear ink containing no colorant is also included in the ink composition of the present invention.
Although there is no restriction | limiting in particular as a coloring agent, The pigment and oil-soluble dye which were excellent in weather resistance and were rich in color reproducibility are preferable, and it can select and use arbitrarily from well-known coloring agents, such as a soluble dye. As the colorant, it is preferable to select a compound that does not function as a polymerization inhibitor from the viewpoint of not reducing the sensitivity of the curing reaction by actinic radiation.
Although it does not necessarily limit as a pigment which can be used for this invention, For example, the organic or inorganic pigment of the following number described in a color index can be used. Examples of red or magenta pigments include Pigment Red 3, 5, 19, 22, 31, 38, 42, 43, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49: 1, 53. : 1, 57: 1, 57: 2, 58: 4, 63: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 88, 104, 108, 112, 122, 123, 144 , 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange 13, 16, 20, 36, blue or cyan pigments include Pigment Blue 1,15,15: 1,15: 2,15: 3,15: 4,15: 6,16,1 -1, 22, 27, 28, 29, 36, 60, Pigment Green 7, 26, 36, 50 as a green pigment, and Pigment Yellow 1, 3, 12, 13, 14, 17, 34 as a yellow pigment , 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 120, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180 , 185, 193, Pigment Black 7, 28, 26, etc. can be used depending on the purpose.

As the white pigment, titanium oxide is preferable.
Titanium oxide is not particularly limited, and can be appropriately selected from known titanium oxides used as white pigments. Both rutile titanium dioxide and anatase titanium dioxide can be used, but rutile titanium dioxide is preferably used because of its low catalytic activity and excellent stability over time.
Titanium oxide is marketed, for example, Tipaque CR60-2, Tipaque A-220 (both manufactured by Ishihara Sangyo Co., Ltd.), KRONOS1001, 1014, 1071, 1074, 1075, 1077, 1078, 1080, 1171, 2044, 2047, 2056, 2063, 2080, 2081, 2084, 2087, 2160, 2190, 2211, 2202, 2222, 2225, 2230, 2233, 2257, 2300, 2310, 2450, 2500, 3000, 3025 (all of which are KRONOS For example).
Further, the titanium oxide may be subjected to a surface treatment as necessary. Specifically, for example, silica, alumina, zinc, zirconia, and organic substance treatment are performed, and weather resistance and lipophilicity differ depending on the treatment method. In the present invention, those treated with alumina, zinc, zirconia or basic organic substances are preferred.

In the present invention, a disperse dye can be used as long as it is soluble in a water-immiscible organic solvent. The disperse dye generally includes a water-soluble dye, but in the present invention, the disperse dye is preferably used as long as it is soluble in a water-immiscible organic solvent.
Preferable specific examples of the disperse dye include C.I. I. Disperse Yellow 5,42,54,64,79,82,83,93,99,100,119,122,124,126,160,184: 1,186,198,199,201,204,224 and 237 C. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54, 55, 66, 73, 118, 119 and 163; I. Disperse Red 54, 60, 72, 73, 86, 88, 91, 92, 93, 111, 126, 127, 134, 135, 143, 145, 152, 153, 154, 159, 164, 167: 1,177 , 181, 204, 206, 207, 221, 239, 240, 258, 277, 278, 283, 311, 323, 343, 348, 356 and 362; I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 165, 165: 1, 165: 2, 176, 183, 185, 197, 198, 201, 214, 224, 225 257, 266, 267, 287, 354, 358, 365 and 368; I. Disperse Green 6: 1 and 9;

  For dispersing the colorant, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, or a paint shaker can be used.

The colorant may be directly added together with each component when preparing the ink composition. Further, in order to improve dispersibility, it may be added to a dispersion medium such as a solvent or a polymerizable compound used in the present invention in advance and uniformly dispersed or dissolved, and then blended.
In the present invention, in order to avoid the deterioration of solvent resistance when the solvent remains in the cured image and the problem of VOC (Volatile Organic Compound) of the remaining solvent, the colorant is polymerizable. It is preferable to add and mix in advance in a dispersion medium such as a compound. In consideration of only dispersibility, it is preferable to select a monomer having the lowest viscosity as the polymerizable compound used for adding the colorant. One or more colorants may be appropriately selected and used according to the purpose of use of the ink composition.

When using a colorant such as a pigment that remains in the ink composition as a solid, the weight average particle diameter of the colorant particles is preferably 0.005 to 0.5 μm, more preferably 0.01. It is preferable to set the colorant, the dispersant, the dispersion medium, the dispersion conditions, and the filtration conditions so that the thickness becomes ˜0.45 μm, more preferably 0.015 to 0.4 μm. This particle size control is preferable because clogging of the head nozzle can be suppressed and the storage stability, transparency, and curing sensitivity of the ink composition can be maintained.
The content of the colorant in the ink composition is appropriately selected depending on the color and purpose of use, but is preferably 0.01 to 30% by weight with respect to the weight of the entire ink composition.

(Component H) Dispersant The ink composition of the present invention preferably contains a dispersant. In particular, when a pigment is used, a dispersant is preferably contained in order to stably disperse the pigment in the ink composition. As the dispersant, a polymer dispersant is preferable.

As the polymer dispersant, DISPERBYK-101, 102, 103, 106, 111, 161, 162, 163, 164, 166, 167, 168, 170, 171, 174, 182 (manufactured by BYK Chemie); EFKA 4010, 4046 4080, 5010, 5207, 5244, 6745, 6750, 7414, 745, 7462, 7500, 7570, 7575, 7580 (manufactured by Fuka Additive); Disperse Aid 6, 8, 15, 9100 (manufactured by San Nopco) ); SOLSPERSE 3000, 5000, 9000, 12000, 13240, 13940, 17000, 22000, 24000, 26000, 28000, 32000, 36000, 39000, 41000, 71000, etc. Sparse dispersant (Noveon); Adeka Pluronic L31, F38, L42, L44, L61, L64, F68, L72, P95, F77, P84, F87, P94, L101, P103, F108, L121, P-123 (( ADEKA Co., Ltd.), Ionette S-20 (manufactured by Sanyo Chemical Industries, Ltd.); Disparon KS-860, 873SN, 874 (polymer dispersing agent), # 2150 (aliphatic polycarboxylic acid), # 7004 (poly) Ether ester type) (manufactured by Enomoto Kasei Co., Ltd.).
The content of the dispersant in the ink composition is appropriately selected depending on the purpose of use, but is preferably 0.05 to 15% by weight with respect to the total weight of the ink composition.

(Component I) Surfactant A surfactant may be added to the ink composition that can be used in the present invention in order to impart stable ejection properties for a long time. Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts.

(Other ingredients)
In the ink composition of the present invention, other components include a sensitizer, a polymerization inhibitor, an ultraviolet absorber, an antioxidant, an anti-fading agent, a conductive salt, a solvent, and the like described in JP-A-2009-096985. A polymer compound, a basic compound, or the like may be added.

(Ink properties)
In the present invention, it is preferable that the viscosity of the ink composition at 25 ° C. is 40 mPa · s or less in consideration of dischargeability. More preferably, it is 5-40 mPa * s, More preferably, it is 7-30 mPa * s. Moreover, it is preferable that the viscosity in discharge temperature (Preferably 25-80 degreeC, More preferably, 25-50 degreeC) is 3-15 mPa * s, and it is more preferable that it is 3-13 mPa * s. It is preferable that the composition ratio of the ink composition of the present invention is appropriately adjusted so that the viscosity is in the above range. By setting the viscosity at room temperature high, even when a porous support is used, penetration of the ink composition into the support can be avoided, and uncured monomers can be reduced. Further, ink bleeding at the time of landing of the ink composition droplets can be suppressed, and as a result, the image quality is improved.

  The surface tension of the ink composition of the present invention at 25 ° C. is preferably 20 to 35 mN / m, and more preferably 23 to 33 mN / m. When recording on various supports such as polyolefin, PET, coated paper, and uncoated paper, 20 mN / m or more is preferable from the viewpoint of bleeding and penetration, and 35 mN / m or less is preferable in terms of wettability.

II. Inkjet recording method and printed matter The inkjet recording method of the present invention is an image forming step of forming an image on a support by ejecting the ink composition of the present invention by an inkjet method (hereinafter also referred to as (a) step). A curing step of irradiating the obtained image with actinic radiation to cure the ink composition to obtain a printed material having a cured image on the support (hereinafter also referred to as (b) step). , Including.
The printed matter of the present invention is manufactured by the ink jet recording method of the present invention.

First, step (a) will be described.
In the present invention, the support is not particularly limited, and a known support can be used. For example, paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), metal plate (for example, , Aluminum, zinc, copper, etc.), plastic films (eg, polyvinyl chloride, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate , Polyvinyl acetal, etc.), paper or plastic film on which the above-mentioned metal is laminated or vapor-deposited. Moreover, a nonabsorbable support body can be used suitably as a support body in this invention.

There is no restriction | limiting in particular as an inkjet recording device used for the inkjet recording method of this invention, The well-known inkjet recording device which can achieve the target resolution can be selected arbitrarily and can be used. That is, any known ink jet recording apparatus including a commercially available product can discharge the ink composition onto the support in the step (a) of the ink jet recording method of the present invention.
Examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and an actinic radiation source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink composition supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head is preferably 1 to 100 pL, more preferably 3 to 42 pL, still more preferably 8 to 30 pL, preferably 320 × 320 to 4,000 × 4,000 dpi, more preferably 400. It can be driven so that it can discharge at a resolution of × 400 to 1,600 × 1,600 dpi, more preferably 720 × 720 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

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

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

Next, step (b) will be described.
The ink composition ejected on the support is cured by irradiation with actinic radiation. This is because the polymerization initiator contained in the ink composition of the present invention is decomposed by irradiation with actinic radiation to generate polymerization initiation species such as radicals, and the polymerization reaction of the polymerizable compound occurs in the function of the initiation species. Because it is promoted. At this time, if a sensitizer is present together with the polymerization initiator in the ink composition, the sensitizer in the system absorbs actinic radiation to be in an excited state, and promotes decomposition of the polymerization initiator by contacting with the polymerization initiator. And a more sensitive curing reaction can be achieved.

  Here, α rays, γ rays, electron beams, X rays, ultraviolet rays, visible light, infrared rays, or the like can be used as the active radiation used. Although the peak wavelength of actinic radiation is based also on the absorption characteristic of a sensitizer, it is preferable that it is 200-600 nm, for example, it is more preferable that it is 300-450 nm, and it is further more preferable that it is 350-420 nm.

In addition, the photopolymerization initiation system of the ink composition of the present invention has sufficient sensitivity even with low-power actinic radiation. Therefore, it is appropriate that the exposure surface illuminance is cured at 1,000 to 3,000 mW / cm ² , more preferably 1,200 to 2,500 mW / cm ² .

Mercury lamps and gas / solid lasers are mainly used as actinic radiation sources, and mercury lamps and metal halide lamps are widely known as light sources used for curing UV photocurable ink jet recording ink compositions. It has been. However, from the viewpoint of environmental protection, mercury-free is strongly desired, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as light sources for photo-curable ink jets.
Further, a light emitting diode (LED) and a laser diode (LD) can be used as the active radiation source. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. If even shorter wavelengths are required, the LED disclosed in US Pat. No. 6,084,250 is capable of emitting actinic radiation centered between 300 nm and 370 nm. Can be illustrated. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. The actinic radiation source preferred in the present invention is a UV-LED, particularly preferably a UV-LED having a peak wavelength at 350 to 420 nm.

The ink composition of the present invention is suitably irradiated with such actinic radiation for 0.01 to 120 seconds, more preferably 0.01 to 90 seconds, and still more preferably 0.01 to 10 seconds. is there.
In the inkjet recording method of the present invention, the ink composition is irradiated with actinic radiation at an exposure surface illuminance of 2,000 mW / cm ² or less within 0.01 to 10 seconds after the ink composition is discharged. Is preferably cured.
Actinic radiation irradiation conditions and a basic irradiation method are disclosed in JP-A-60-132767. Specifically, the light source is provided on both sides of the head unit including the ink composition discharge device, and the head unit and the light source are scanned by a so-called shuttle method. Irradiation with actinic radiation is performed for a certain time (preferably 0.01 to 0.5 seconds, more preferably 0.01 to 0.3 seconds, still more preferably 0.01 to 0.15 seconds) after landing of the ink composition. ). In this way, by controlling the time from landing to irradiation of the ink composition to an extremely short time, it is possible to prevent the ink composition that has landed on the support from bleeding before curing. In addition, since the ink composition can be exposed to a porous support before reaching the deep part where the light source does not reach, it is preferable because residual unreacted monomer can be suppressed.
Further, the curing may be completed by another light source that is not driven. International Publication No. 99/54415 pamphlet discloses a method using an optical fiber or a method of irradiating a recording unit with UV light by applying a collimated light source to a mirror surface provided on the side of the head unit, as an irradiation method. Such a curing method can also be applied to the ink jet recording method of the present invention.

  By adopting the ink jet recording method as described above, the dot diameter of the landed ink composition can be kept constant even on various supports having different surface wettability, and the image quality is improved. In addition, in order to obtain a color image, it is preferable to superimpose in order from the color with the lowest brightness. By superimposing the ink compositions in order of low lightness, it becomes easy for the irradiation rays to reach the lower ink composition, and good curing sensitivity, reduction of residual monomers, and improvement in adhesion can be expected. In addition, irradiation can be performed by discharging all colors and collectively exposing, but exposure for each color is preferable from the viewpoint of promoting curing.

In the ink jet recording method of the present invention, an ink set containing one or more ink compositions of the present invention can be suitably used. The order of the colored ink compositions to be ejected is not particularly limited, but it is preferable that the colored ink composition having a low lightness is applied to the support. When using an ink composition of yellow, cyan, magenta, and black as the ink composition of the present invention, it is preferably applied on the support in the order of yellow → cyan → magenta → black. Further, when white is added to this, it is preferably applied on the support in the order of white → yellow → cyan → magenta → black. Furthermore, the present invention is not limited to this, and the present invention is also used as an ink set including at least seven colors in total, that is, a light cyan and light magenta ink composition and a cyan, magenta, black, white and yellow dark ink composition. In this case, it is preferable to apply on the support in the order of white → light cyan → light magenta → yellow → cyan → magenta → black.
Thus, the ink composition of the present invention can form an image on the surface of the support by being cured with high sensitivity by irradiation with actinic radiation.

When the ink composition of the present invention is prepared in a plurality of colors and used as an ink set, at least one ink composition of the present invention is included, and two or more combinations of the ink composition of the present invention or an ink composition other than the present invention are combined. The ink composition of the present invention having a color selected from the group consisting of cyan, magenta, yellow, black, white, light magenta, and light cyan is not particularly limited. It is preferable to include at least one.
The ink set of the present invention can be suitably used for the ink jet recording method of the present invention.
In order to obtain a full-color image using the ink composition of the present invention, the ink set is an ink set in which at least four dark ink compositions comprising yellow, cyan, magenta, and black are combined. It is more preferable that the ink set is a combination of five color ink compositions composed of yellow, cyan, magenta, black, and white, and five colors composed of yellow, cyan, magenta, black, and white. More preferably, the ink set is a combination of a dark ink composition and a two-color ink composition comprising light cyan and light magenta.
The “dark ink composition” in the present invention means an ink composition in which the content of the colorant exceeds 1% by weight of the entire ink composition. There is no restriction | limiting in particular as said coloring agent, A well-known coloring agent can be used, A pigment and a disperse dye can be illustrated.
The ink set of the present invention includes at least one dark color ink composition and at least one light color ink composition, and the dark color ink composition and the light color ink composition use a colorant having a similar color. The ratio of the colorant concentration between the dark color ink composition and the light color ink composition is preferably dark color ink composition: light color ink composition = 15: 1 to 4: 1, and 12: 1 to The ratio is more preferably 4: 1, and more preferably 10: 1 to 4.5: 1. Within the above range, a vivid full-color image with little graininess can be obtained.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples. In the following description, “parts” means “parts by weight” unless otherwise specified, and “%” means “% by weight”.

(Preparation of yellow mill base Y)
Y pigment (yellow pigment): NOVOPERM YELLOW H2G 33 parts PEA (2-phenoxyethyl acrylate) 57 parts SOLPERSE 2000 10 parts The above ingredients were stirred to obtain yellow mill base Y. The pigment mill base was prepared by dispersing in a disperser motor mill M50 (manufactured by Eiger) and dispersing for 8 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

  Similar to the preparation of yellow mill base Y, cyan mill base C, magenta mill base M, black mill base K, and white mill base W were prepared under the composition and dispersion conditions shown in Table 1.

(Pigment)
・ Y pigment (yellow pigment); NOVOPERM YELLOW H2G (manufactured by Clariant)
C pigment (cyan pigment); IRGALITE BLUE GLVO (Ciba Specialty Chemicals)
・ M pigment (magenta pigment); CINQUASIA MAGENTA RT-355D (manufactured by Ciba Specialty Chemicals)
・ K pigment (black pigment); SPECIAL BLACK 250 (Ciba Specialty Chemicals)
・ W pigment (white pigment); Titanium oxide treated with alumina (monomer)
PEA; 2-phenoxyethyl acrylate (SR339, manufactured by SARTOMER)
(Dispersant)
・ SOLSPERSE2000 (manufactured by Lubrizol)
・ SOLSPERSE32000 (manufactured by Lubrizol)
・ SOLSPERSE5000 (manufactured by Lubrizol)
・ SOLSPERSE 36000 (manufactured by Lubrizol)

(Examples 1-34 and Comparative Examples 1-11)
<Method for producing ink composition>
Ink compositions of Examples 1 to 34 and Comparative Examples 1 to 11 were obtained by mixing and stirring the materials described in Tables 2 to 6. In addition, the numerical value in a table | surface represents the compounding quantity (part by weight) of each component.

<Inkjet image recording>
Next, recording on a recording medium was performed using a commercially available inkjet recording apparatus having a piezoelectric inkjet nozzle. The ink supply system was composed of an original tank, supply piping, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head, and heat insulation and heating were performed from the ink supply tank to the inkjet head portion. Temperature sensors were provided near the ink supply tank and the nozzles of the inkjet head, respectively, and temperature control was performed so that the nozzle portions were always 40 ° C. ± 2 ° C. The piezo-type inkjet head was driven so that 1 to 10 pl multi-size dots could be ejected at a resolution of 4,800 × 4,800 dpi. After landing, UV light is condensed to an exposure surface illumination of 1,200 mW / cm ² , and the exposure system, main scanning speed, and emission frequency are set so that irradiation starts 0.1 seconds after the ink composition has landed on the recording medium. It was adjusted. Further, the exposure time was variable, and exposure energy was irradiated. A HAN250NL high-cure mercury lamp (manufactured by GS Yuasa Corporation) was used as the ultraviolet lamp. In the present invention, dpi represents the number of dots per 2.54 cm. As a recording medium, an ester film E5000 (thickness 125 μm, manufactured by Toyobo Co., Ltd.) was used.

<Ink evaluation>
(Curable)
In accordance with the inkjet recording method, a solid image having an average film thickness of 12 μm was drawn, and the exposure energy amount (mJ / cm ² ) at which no stickiness was felt on the image surface after ultraviolet irradiation was defined as curing sensitivity. The smaller the exposure energy amount, the higher the sensitivity.
The curing sensitivity was evaluated according to the following criteria.
10: 1,000mJ / cm ² less than 9: 1,000mJ / cm ² or more 1,500 mJ / cm ² less than 8: 1,500mJ / cm ² or more 2,000 mJ / cm ² less than 7: 2,000mJ / cm ² or more Less than 2,500 mJ / cm ² 6: 2,500 mJ / cm ² or more and less than 3,000 mJ / cm ² 5: 3,000 mJ / cm ² or more and less than 3,500 mJ / cm ² 4: 3,500 mJ / cm ² or more 4, less than ^{000mJ / cm 2 3: 4,000mJ /} cm 2 or more 4,500mJ / cm ² less than ^2: 4,500mJ / cm 2 or more 5,000 mJ / cm ² less than 1: 5,000mJ / cm ² or more reference 6-10 If it is in the range, there will be no practical problem.

(Adhesion to recording medium)
The ink composition was applied to the surface of a white polyvinyl chloride sheet (thickness 220 μm) as a recording medium using a K hand coater (bar No. 2) so as to have a wet film thickness of 12 μm. Next, inside the experimental UV mini conveyor device CSOT (manufactured by GS Yuasa Power Supply Co., Ltd.) equipped with an ozone-less metal halide lamp MAN250L and set to a conveyor speed of 9.0 m / min and an exposure intensity of 2.0 W / cm ^2. , Repeatedly passed 12 times and radiation cured. The adhesion to the recording medium was evaluated according to the following criteria by ISO 2409 (cross cut method) using this cured coating film.
5: The edges of the cuts are completely smooth, and there is no peeling to the eyes of any lattice.
4: Small peeling of the coating film occurs at the intersection of cuts. The cross cut is not affected by more than 5%.
3: Peel along the edge of the cut of the coating and / or at the intersection. The cross-cut portion is affected by more than 5% but not more than 15%.
2: The coating film is partially or completely peeled along the edge of the cut, and / or various parts of the eye are partially or completely peeled off. The cross-cut part is affected by more than 15% but not more than 35%.
1: The coating film is partially or completely peeled along the edge of the cut, and / or some eyes are partially or completely peeled off. The cross-cut portion is affected by more than 35% but not more than 65%.
0: The degree of peeling exceeds 1.
If it is the range of the reference | standard 3-5, a practical problem will not arise.

(Glossiness)
The ink composition was drawn four times on a white polyvinyl chloride sheet (thickness: 220 μm) as a recording medium, assuming four colors using an inkjet printer Luxel Jet (manufactured by Fujifilm Corporation). The gloss feeling was evaluated with a glossiness of 60% specified by JIS K 5600 using a gloss meter IG-410 (manufactured by HORIBA).
10: 60 degree gloss 60 ~
9: 60 degree glossiness 55-60
8: 60 degree gloss 50-55
7: 60 degree gloss 45-50
6: 60 degree gloss 40-45
5: 60 degree glossiness 30-40
4: 60 degree gloss 25-30
3: 60 degree gloss 20-20
2: 60 degree gloss 15-20
1: 60 degree gloss 0-15
If it is the range of standard 6-10, a practical problem will not arise.

(Flexibility of cured film)
The flexibility of the cured film is the stretch rate until the image breaks at room temperature (about 25 ° C.) when the printed material having a length of 6 cm and a width of 2 cm recorded by the ink jet recording method is stretched together with the polyvinyl chloride sheet. Was measured and evaluated according to the following criteria.
10: Stretch rate is 100% or more 9: Stretch rate is 90% or more and less than 100% 8: Stretch rate is 80% or more and less than 90% 7: Stretch rate is 70% or more and less than 80% 6: Stretch rate is 60 %: Less than 70% 5: Stretch rate is 55% or more, less than 60% 4: Stretch rate is 50% or more, less than 55% 3: Stretch rate is 45% or more, less than 50% 2: Stretch rate is 40% or more Less than 45% 1: Extension rate is less than 40%

The abbreviations described in Tables 2 to 6 are as follows.
(Component A)
Irg 819; bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (IRGACURE 819, manufactured by Ciba Specialty Chemicals)
Irg 184; 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE 184, manufactured by Ciba Specialty Chemicals)
ITX: Mixture of 2-isopropylthioxanthone and 4-isopropylthioxanthone (FIRSTCURE ITX, manufactured by ALBEMARLE)
TPO; 2,4,6-trimethylbenzoyldiphenylphosphine oxide (DAROCUR TPO, manufactured by Ciba Specialty Chemicals)
(Component B)
Ebecryl 3420; epoxy acrylate (functional group number 2, molecular weight 500, viscosity 22,000 mPa · s (25 ° C.), manufactured by Daicel Cytec Co., Ltd.)
Ebecryl 3703; amine-modified bisphenol A type epoxy acrylate (number of functional groups 2, molecular weight 850, viscosity 4,250 mPa · s (60 ° C.), manufactured by Daicel Cytec Co., Ltd.)

（Ｃ−５は、ＥＯＥＯＥＡ（ａｌｄｒｉｃｈ社製）、Ｃ−１３はＴＨＦＡ（東京化成工業（株）製）、Ｃ−１６は、ＣＤ６１１（ＳＡＲＴＯＭＥＲ製）である。）

(C-5 is EOEOEA (manufactured by Aldrich), C-13 is THFA (manufactured by Tokyo Chemical Industry Co., Ltd.), and C-16 is CD611 (manufactured by SARTOMER).)

(Component D)
FA-511A; dicyclopentenyl acrylate (manufactured by Hitachi Chemical Co., Ltd.)
FA-512A; dicyclopentenyloxyethyl acrylate (manufactured by Hitachi Chemical Co., Ltd.)
FA-513A; dicyclopentanyl acrylate (manufactured by Hitachi Chemical Co., Ltd.)
IBOA; isobornyl acrylate (SR506, manufactured by SARTOMER)
PEA; 2-phenoxyethyl acrylate (SR339, manufactured by SARTOMER)

(Other monomers and oligomers)
HDDA; 1,6-hexanediol diacrylate (SR238, manufactured by SARTOMER)
UA-122P; urethane acrylate (functional group number 2, weight average molecular weight 1,100, viscosity 43,000 mPa · s (40 ° C.), manufactured by Shin-Nakamura Chemical Co., Ltd.)
UA-5201; urethane acrylate (number of functional groups 2, weight average molecular weight 1,000, viscosity 43,000 mPa · s (25 ° C.), manufactured by Shin-Nakamura Chemical Co., Ltd.)
-Actilane 251; trifunctional urethane acrylate (manufactured by Akcros)
・ Trimethylolpropane triacrylate (Aldrich)
・ 2- (vinyloxyethoxy) ethyl acrylate (manufactured by Nippon Shokubai Co., Ltd.)
・ 2-hydroxypropyl acrylate (manufactured by Aldrich)
・ Diethylene glycol divinyl ether (Aldrich)
・ N-Vinylformamide (Aldrich)
・ Tripropylene glycol diacrylate (Aldrich)

(Dispersant)
・ Solsperse 13920 (manufactured by Lubrizol)
・ Sol Sparse 24000 (manufactured by Lubrizol)
P-st / AA / BA; copolymer of styrene / acrylic acid / butyl acrylate (acid value = 30, weight average molecular weight = 6,000)

Claims (8)

(Component A) Photopolymerization initiator,
(Component B) 1 to 10% by weight of the epoxy (meth) acrylate oligomer based on the total weight of the ink composition;
(Component C) As the monofunctional monomer represented by the formula (C-1), a monofunctional monomer selected from the group consisting of the following (C-1) to (C-20) is used with respect to the total weight of the ink composition. 10 to 30% by weight, and
(Component D) containing a monofunctional monomer other than the monofunctional monomer represented by the formula (C-1) in an amount of 5 to 70% by weight based on the total weight of the ink composition
Component A contains an acylphosphine compound, an α-hydroxyacetophenone compound, and a thioxanthone compound,
The weight average molecular weight of component B is 330 to 1,500;
Component D includes at least one compound selected from the group consisting of isobornyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentanyl (meth) acrylate. An ink composition for ink jet recording, comprising:

(In formula (C-1), R ¹ represents a hydrogen atom or a methyl group, and X is a single bond, an alkylene group, an oxyalkylene group or a group in which two or more of the above oxyalkylene groups are combined, an ester bond, or these R ² and R ³ each independently represents a hydrogen atom or an alkyl group, and R ^{4 to} R ⁸ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group. Or an aminoalkyl group, at least one of R ^{4 to} R ⁸ may be a hydrogen atom, and any two or more of R ^{4 to} R ⁸ may be bonded to form a cyclic structure.)

(In (C-1) to (C-20), R represents a hydrogen atom or a methyl group.) The ink composition according to claim 1, wherein 50% by weight or more of component A is an acylphosphine compound. The ink composition according to claim 1 or 2 , wherein the viscosity of Component B at 25 ° C is 500 to 50,000 mPa · s. The ink composition according to any one of claims 1 to 3 , further comprising a pigment. The ink composition according to any one of claims 1 to 4 , further comprising 1 to 10% by weight of a urethane (meth) acrylate oligomer having a weight average molecular weight of 350 to 2,800 based on the total weight of the ink composition. object. An image forming step of forming an image on a support by discharging the ink composition according to any one of claims 1 to 5 by an inkjet method, and
An inkjet recording method comprising: a curing step of irradiating the obtained image with actinic radiation to cure the ink composition to obtain a printed material having a cured image on the support. The maximum illumination intensity of the actinic radiation is less than 1,000 mW / cm ² or more 3,000 mW / cm ^2, the ink jet recording method according to claim 6. Printed matter characterized in that it is manufactured by the ink jet recording method according to claim 6 or 7.