JP2013057043A - Inkjet ink composition and inkjet recording method - Google Patents

Abstract

【選択図】なしAn inkjet ink composition having excellent ejection stability, curability, adhesion of a cured film to a substrate and glossiness is provided.
SOLUTION: (Component A) a radically polymerizable compound, (Component B) a radical polymerization initiator, and (Component C) a colorant, and as component A, a monofunctional polymerizable compound represented by the formula (I) An inkjet ink composition comprising a compound and a polyfunctional polymerizable compound represented by formula (II). In formula (I), R ¹ , R ² and R ³ each independently represents a hydrogen atom, a methyl group or an ethyl group, and X ¹ represents a single bond or a divalent linking group. A representative example of the compound represented by the formula (II) is a compound in which three (meth) acryloyloxy groups are bonded to an alkylene oxide adduct of trimethylolpropane.

[Selection figure] None

Description

  The present invention relates to an inkjet ink composition and an inkjet recording method.

As an image recording method for forming an image on a recording medium such as paper based on an image data signal, there are an electrophotographic method, a sublimation type and a melt type thermal transfer method, an ink jet method and the like.
The ink jet method is an ink composition because the printing apparatus is inexpensive and does not require a plate at the time of printing, and the ink composition is ejected only on the required image portion to form an image directly on the recording medium. Can be used efficiently, especially in the case of small lot production. Furthermore, it has low noise and is excellent as an image recording method, and has attracted attention in recent years.
In particular, an ink-jet ink composition that can be cured by irradiation with radiation such as ultraviolet rays (a radiation-curable ink composition for inkjet recording) cures most of the components of the ink composition upon irradiation with radiation such as ultraviolet rays. This method is superior in that it can be printed on various recording media because it is excellent in drying properties and is less likely to bleed as compared with the ink-based ink composition.
Moreover, as a conventional inkjet ink composition, the thing of patent documents 1-3 is mentioned.

JP 2007-131755 A Special table 2010-52295 gazette JP 2007-131754 A

  An object of the present invention is to provide an ink jet ink composition having excellent curability and ejection stability, and excellent cured substrate adhesion and gloss, and an ink jet recording method using the ink jet ink composition. It is to be.

The above-described problems of the present invention have been solved by means described in the following <1> and <8>. It is described below together with <2> to <7> which are preferred embodiments.
<1> (Component A) a radically polymerizable compound, (Component B) a radical polymerization initiator, and (Component C) a colorant, and as Component A, (Component A-1) a monofunctional radically polymerizable compound and (Component A-2) containing a polyfunctional radical polymerizable compound, and as Component A-1, (Component A-1-1) N-vinyl compound and (Component A-1-2) represented by the formula (I) The content of component A-1 is 50 to 90% by mass relative to the total mass of component A, and the content of component A-1-1 is relative to the total mass of component A-1. 10 to 40% by mass, the content of Component A-1-2 is 5 to 90% by mass with respect to the total mass of Component A-1, and Component A-2 is a compound represented by the formula (II) A), wherein the content of component A-2 is 0.1 to 25% by mass relative to the total mass of component A Click jet ink composition,

（式（I）中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に、水素原子、メチル基、又は、エチル基を表し、Ｘ¹は単結合、又は、二価の連結基を表す。）

(In formula (I), R ¹ , R ² and R ³ each independently represents a hydrogen atom, a methyl group or an ethyl group, and X ¹ represents a single bond or a divalent linking group.)

（式（II）中、Ｒ¹¹はそれぞれ独立に水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹²は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹³はそれぞれ独立に水素原子、又はメチル基を表し、Ｘ²は単結合、又は二価の連結基を表し、ｐ、ｑ及びｒはそれぞれ独立に０〜５の整数を表す。）

(In formula (II), each R ¹¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and R ¹² represents a hydrogen atom or an optionally substituted carbon atom 1. Represents an alkyl group of ˜6, R ¹³ independently represents a hydrogen atom or a methyl group, X ² represents a single bond or a divalent linking group, and p, q and r each independently represent 0 to 5 Represents an integer.)

<2> The ink-jet ink composition according to <1>, wherein component A-1-1 is N-vinylcaprolactam,
<3> The above component A-1, further comprising (component A-1-3) a (meth) acrylate compound having an aromatic hydrocarbon ring in an amount of 5 to 40% by mass relative to the total mass of component A-1. <1> or the inkjet ink composition according to <2>,
<4> The above-mentioned <1> containing (Component B-1) a monoacylphosphine oxide compound and / or (Component B-2) a bisacylphosphine oxide compound and (Component B-3) a thioxanthone compound as Component B >-<3> any one of the inkjet ink compositions,
<5> At least one of the compounds represented by formula (II) is trimethylolpropane triacrylate, and the content thereof is 0.5 to 8% by mass with respect to the total mass of component A. <4> The inkjet ink composition according to any one of
<6> Any of the above <1> to <5>, which contains (Component B-1) a monoacylphosphine oxide compound as Component B, and the content thereof is 3% by mass or less based on the total mass of the ink composition. Or an inkjet ink composition according to claim 1,
<7> The inkjet ink composition according to any one of the above <1> to <6>, which contains at least one compound represented by formula (II ′) as component A-2.

（式（II’）中、Ｒ¹¹は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹²は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹³はそれぞれ独立に水素原子、又はメチル基を表し、Ｘ²は単結合、又は二価の連結基を表し、ｐ、ｑ及びｒはそれぞれ独立に０〜５の整数を表し、ｐ＋ｑ＋ｒ≧１の関係を満たす。）

(In the formula (II ′), R ¹¹ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and R ¹² represents a hydrogen atom or an optionally substituted carbon atom having 1 to 6 carbon atoms. R ¹³ represents each independently a hydrogen atom or a methyl group, X ² represents a single bond or a divalent linking group, and p, q and r are each independently an integer of 0 to 5 And satisfies the relationship of p + q + r ≧ 1.)

<8> (a ¹ ) A step of discharging the ink-jet ink composition according to any one of the above <1> to <7> on a recording medium, and (b ¹ ) the discharged ink-jet ink composition A step of irradiating the product with actinic radiation to cure the inkjet ink composition.

  According to the present invention, there are provided an ink jet ink composition having excellent curability and ejection stability, excellent cured substrate adhesion and gloss, and an ink jet recording method using the ink jet ink composition. can do.

  Hereinafter, the present invention will be described in detail.

(Inkjet ink composition)
The ink-jet ink composition of the present invention (hereinafter also referred to as “ink composition”) is excellent in curability and ejection stability by satisfying the following first embodiment or second embodiment. A printed matter excellent in substrate adhesion and gloss of the cured film can be obtained.
The ink-jet ink composition in the first embodiment of the present invention contains (Component A) a radical polymerizable compound, (Component B) a radical polymerization initiator, and (Component C) a colorant. Component A-1) A monofunctional radically polymerizable compound and (Component A-2) a polyfunctional radically polymerizable compound, and as Component A-1, (Component A-1-1) N-vinyl compound and (Component A-1-2) a compound represented by formula (I), the content of component A-1 is 50 to 90% by mass with respect to the total mass of component A, The content is 10 to 40% by mass with respect to the total mass of Component A-1, the content of Component A-1-2 is 5 to 90% by mass with respect to the total mass of Component A-1, and Component A- 2 contains at least two compounds represented by formula (II), and the content of component A-2 is component A Mass relative characterized in that 0.1 to 25 wt%.

（式（I）中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に、水素原子、メチル基、又は、エチル基を表し、Ｘ¹は単結合、又は、二価の連結基を表す。）

(In formula (I), R ¹ , R ² and R ³ each independently represents a hydrogen atom, a methyl group or an ethyl group, and X ¹ represents a single bond or a divalent linking group.)

（式（II）中、Ｒ¹¹はそれぞれ独立に水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹²は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹³はそれぞれ独立に水素原子、又はメチル基を表し、Ｘ²は単結合、又は二価の連結基を表し、ｐ、ｑ及びｒはそれぞれ独立に０〜５の整数を表す。）

(In formula (II), each R ¹¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and R ¹² represents a hydrogen atom or an optionally substituted carbon atom 1. Represents an alkyl group of ˜6, R ¹³ independently represents a hydrogen atom or a methyl group, X ² represents a single bond or a divalent linking group, and p, q and r each independently represent 0 to 5 Represents an integer.)

  The ink-jet ink composition in the second embodiment of the present invention contains (Component A) a radical polymerizable compound, (Component B) a radical polymerization initiator, and (Component C) a colorant. Component A-1) A monofunctional radically polymerizable compound and (Component A-2) a polyfunctional radically polymerizable compound, and as Component A-1, (Component A-1-1) N-vinyl compound and (Component A-1-2) a compound represented by formula (I), the content of component A-1 is 50 to 90% by mass with respect to the total mass of component A, The content is 10 to 40% by mass with respect to the total mass of Component A-1, the content of Component A-1-2 is 5 to 90% by mass with respect to the total mass of Component A-1, and Component A- 2 contains at least one compound represented by the formula (II ′), and the content of component A-2 is component A Wherein the total weight to 0.1 to 25 mass%.

（式（I）中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に、水素原子、メチル基、又は、エチル基を表し、Ｘ¹は単結合、又は、二価の連結基を表す。）

(In formula (I), R ¹ , R ² and R ³ each independently represents a hydrogen atom, a methyl group or an ethyl group, and X ¹ represents a single bond or a divalent linking group.)

（式（II’）中、Ｒ¹¹は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹²は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹³はそれぞれ独立に水素原子、又はメチル基を表し、Ｘ²は単結合、又は二価の連結基を表し、ｐ、ｑ及びｒはそれぞれ独立に０〜５の整数を表し、ｐ＋ｑ＋ｒ≧１の関係を満たす。）

(In the formula (II ′), R ¹¹ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and R ¹² represents a hydrogen atom or an optionally substituted carbon atom having 1 to 6 carbon atoms. R ¹³ represents each independently a hydrogen atom or a methyl group, X ² represents a single bond or a divalent linking group, and p, q and r are each independently an integer of 0 to 5 And satisfies the relationship of p + q + r ≧ 1.)

  In the present invention, “(meth) acryl” is a term including one or both of “acryl” and “methacryl”, and “(meth) acrylate” is “acrylate”. And “methacrylate”, or both.

  The ink composition of the present invention is an oil-based ink composition that can be cured by actinic radiation (also referred to as actinic energy rays). “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 comprises, as a first embodiment, N-vinylcaprolactam as component A-1-1, cyclic trimethylolpropane formal acrylate as component A-1-2, and formula (II) as component A-2. It is preferable that at least two types of trifunctional ethylenically unsaturated compounds represented by formula (II) are contained, and as component B, a monoacylphosphine oxide compound and / or a bisacylphosphine oxide compound and a thioxanthone compound are contained. The ink composition of the present invention can provide an ink-jet ink composition having excellent curability.
In the ink composition of the present invention, as a second embodiment, N-vinylcaprolactam as component A-1-1, cyclic trimethylolpropane formal acrylate as component A-1-2, and formula (II) as component A-2 It is preferable to contain at least one trifunctional ethylenically unsaturated compound represented by ') and to contain, as Component B, a monoacylphosphine oxide compound and / or a bisacylphosphine oxide compound and a thioxanthone compound. The ink composition of the present invention can provide an ink-jet ink composition having excellent curability.
Hereinafter, the ink composition of the present invention will be described.

The ink composition of the present invention contains, as component A, compounds of component A-1 and component A-2 described below, and the content of component A-1 is 50 to 90% by mass with respect to the total mass of component A. The content of Component A-1-1 is 10 to 40% by mass with respect to the total mass of Component A-1, and the content of Component A-1-2 is 5 with respect to the total mass of Component A-1. It is -90 mass%, and content of component A-2 is 0.1-25 mass% with respect to the total mass of component A. FIG.
Below, component A-1 and A-2 are demonstrated.

(Component A-1) Monofunctional radically polymerizable compound The ink composition of the present invention contains (Component A-1) a monofunctional radically polymerizable compound.
Component A-1 is preferably a radical polymerizable compound having one ethylenically unsaturated group. Among these, (Component A-1-1) N-vinyl compounds and (Component A-1-2) compounds represented by formula (I) are more preferable.
The ink composition of the present invention contains, as Component A-1, (Component A-1-1) an N-vinyl compound and (Component A-1-2) a compound represented by Formula (I). Further preferred.
Below, component A-1-1 and component A-1-2 are demonstrated.

The ink composition of the present invention contains (Component A-1-1) an N-vinyl compound.
Component A-1-1 will be described below.
Component A-1-1 can preferably contain N-vinyl lactams or N-vinylformamide. Moreover, as N-vinyl lactam, the compound represented by Formula (a) is preferable.

<N-vinyl lactams>
The ink composition of the present invention preferably contains a compound represented by the formula (a) as Component A-1-1.

In the formula (a), n represents an integer of 2 to 6, and n is 3 to 5 from the viewpoint of flexibility after the ink composition is cured, adhesion to a recording medium, and availability of raw materials. It is preferable that n is 3 or 5, and n is 5, that is, N-vinylcaprolactam is particularly preferable. N-vinylcaprolactam is preferable because it is excellent in safety, is general-purpose and can be obtained at a relatively low price, and provides particularly good ink curability and good adhesion of a cured film to a recording medium.
In the N-vinyllactam, a hydrogen atom on the lactam ring may be substituted with a substituent such as an alkyl group or an aryl group, or a lactam ring and a saturated or unsaturated ring structure may be linked. Good.
The compound represented by Formula (a) may be used individually by 1 type, or may use 2 or more types together.

<N-vinylformamide>
Preferred examples of N-vinylformamide include compounds having the following structure. As a compound having the following structure, a beam set 770 of Arakawa Chemical Industries, Ltd. can be obtained as a commercial product.

<Compound represented by formula (I)>
The ink composition of the present invention contains a compound represented by the formula (I) as Component A-1-2.
Hereinafter, the compound represented by formula (I) used as component A-1-2 of the ink composition of the invention will be described.

（式（I）中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に、水素原子、メチル基、又は、エチル基を表し、Ｘ¹は単結合、又は、二価の連結基を表す。）

(In formula (I), R ¹ , R ² and R ³ each independently represents a hydrogen atom, a methyl group or an ethyl group, and X ¹ represents a single bond or a divalent linking group.)

R ¹ is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.
R ² and R ³ are each independently preferably a hydrogen atom or a methyl group, and more preferably R ² and R ³ are both hydrogen atoms.
The divalent linking group for X ¹ is not particularly limited as long as it does not significantly impair the effects of the present invention, but it is a divalent hydrocarbon group or a divalent group in which a hydrocarbon group and an ether bond are combined. It is preferably a divalent hydrocarbon group, a poly (alkyleneoxy) group, or a poly (alkyleneoxy) alkylene group. Moreover, it is preferable that carbon number of the said bivalent coupling group is 1-60, and it is more preferable that it is 1-20. X ¹ is preferably a single bond, a divalent hydrocarbon group, or a divalent group in which a hydrocarbon group and an ether bond are combined, and is a C 1-20 divalent hydrocarbon group. The divalent hydrocarbon group having 1 to 8 carbon atoms is more preferable, and a methylene group is particularly preferable.

  Although the specific example of component A-1-2 is given below, it is not limited to these compounds. In the following specific examples, R represents a hydrogen atom or a methyl group.

Among these, cyclic trimethylolpropane formal (meth) acrylate is preferable, and cyclic trimethylolpropane formal acrylate (CTFA) is particularly preferable.
Component A-1-2 may be a commercially available product, and a specific example of the commercially available product is preferably SR531 (manufactured by Sartomer).

The content of Component A-1 in the ink composition of the present invention is 50 to 90% by mass, preferably 50 to 80% by mass, more preferably 60 to 80% by mass, based on the total mass of Component A. is there.
If the content of component A-1 is less than 50% by mass or more than 90% by mass, desired ejection stability and substrate adhesion of the resulting cured film cannot be obtained.
By containing component A-1 in the above range, an ink composition having excellent ejection stability and excellent substrate adhesion of the resulting cured film can be obtained.

  Further, the content of Component A-1-1 in the ink composition of the present invention is 10 to 40% by mass, preferably 15 to 30% by mass, based on the total mass of Component A-1.

  Further, the content of Component A-1-2 in the ink composition of the present invention is 5 to 90% by mass, preferably 30 to 90% by mass, based on the total mass of Component A-1.

(Component A-2) Polyfunctional radical polymerizable compound The ink composition of the present invention contains (Component A-2) a polyfunctional radical polymerizable compound.
Component A-2 is preferably a radically polymerizable compound having two or more ethylenically unsaturated groups. Moreover, as component A-2, the compound represented by Formula (II) is contained.

<Compound represented by formula (II)>
The ink composition of the first embodiment of the present invention contains at least two compounds represented by the formula (II) as Component A-2.
Hereinafter, the compound represented by the formula (II) used as Component A-2 of the ink composition of the invention will be described.

（式（II）中、Ｒ¹¹はそれぞれ独立に水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹²は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹³はそれぞれ独立に水素原子、又はメチル基を表し、Ｘ²は単結合、又は二価の連結基を表し、ｐ、ｑ及びｒはそれぞれ独立に０〜５の整数を表す。）

(In formula (II), each R ¹¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and R ¹² represents a hydrogen atom or an optionally substituted carbon atom 1. Represents an alkyl group of ˜6, R ¹³ independently represents a hydrogen atom or a methyl group, X ² represents a single bond or a divalent linking group, and p, q and r each independently represent 0 to 5 Represents an integer.)

In formula (II), R ¹¹ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and the alkyl group may be linear or branched. Examples of the substituent include a halogen atom, a hydroxyl group, and an amino group. R ¹¹ is preferably a hydrogen atom, a methyl group, an ethyl group, or a propyl group, and particularly preferably a hydrogen atom or a methyl group.

In the formula (II), R ¹² represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and the alkyl group may be linear or branched. Examples of the substituent include a halogen atom, a hydroxyl group, and an amino group. R ¹² is preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group, a methylol group, or an ethylol group, and particularly preferably a hydrogen atom, a methyl group, an ethyl group, or a methylol group.

R ¹³ each independently represents a hydrogen atom or a methyl group, preferably a hydrogen atom.

In formula (II), X ² represents a single bond or a divalent linking group, and the divalent linking group is not particularly limited as long as it does not significantly impair the effects of the present invention. It is preferably a divalent linking group in which a group or a hydrocarbon group and an ether bond are combined.
X ² is preferably a single bond, a divalent hydrocarbon group having 1 to 6 carbon atoms, or an oxyalkylene group having 1 to 6 carbon atoms, and particularly preferably a single bond or a methylene group.

In formula (II), p, q and r each independently represent an integer of 0 to 5. p, q, and r are each independently preferably 0 to 3, particularly preferably 0 to 2. Examples of preferable combinations of p, q, and r include p = q = r = 0, p = q = r = 1, or p = q = r = 2.
Hereinafter, specific examples of the compound when p, q, and r have preferable values will be described, but the present invention is not limited thereto.

Preferred embodiments of the compound of formula (II) when p = q = r = 0 are satisfied. Trimethylolpropane triacrylate (when R ¹² is an ethyl group, R ¹³ is a hydrogen atom, and X ² is a methylene group), Trimethylolpropane trimethacrylate (when R ¹² is an ethyl group, R ¹³ is a methyl group, X ² is a methylene group), trimethylol ethane triacrylate (R ¹² is a methyl group, R ¹³ is a hydrogen atom, X ² is a methylene group) ), Trimethylolethane trimethacrylate (when R ¹² is a methyl group, R ¹³ is a methyl group, and X ² is methylene), tetramethylol methane triacrylate (R ¹² is a methylol group, R ¹³ is a hydrogen atom, X ² for methylene group), tetramethylolmethane trimethacrylate (R ¹² is a methylol group, R ¹³ in the case of methyl group, X ² is a single bond), glycerin Emissions triacrylate (R ¹² is a hydrogen atom, R ¹³ is a hydrogen atom, X ² in the case of single bond), glycerol trimethacrylate (R ¹² is a hydrogen atom, R ¹³ is a methyl group, X ² in the case of methylene group) Can be mentioned.
These are commercially available as SR351S, SR444, SR350, etc. from Sartomer.

  Preferred embodiments of the compound of formula (II) when p = q = r = 1 include compounds of the following structural formula. As these products, SR454, SR9020, SR492, Denacol acrylate DA-314 (Nagase ChemteX Corporation) and the like can be obtained as commercial products from Sartomer.

  Preferable embodiments of the compound of the formula (II) when p, q and r take other values include compounds having the following structural formula. These are commercially available as SR9021, SR9035, SR415 from Sartomer, Aronix M-320 from Toagosei Co., Ltd., NK ester A-GLy-9E from Shin-Nakamura Chemical Co., Ltd., and the like.

  The compound represented by formula (II) is preferably used in combination of two or more. A preferred embodiment in that case includes the mixed use of (II-a) and (II-d), or the mixed use of trimethylolpropane triacrylate and (II-d), and trimethylolpropane triacrylate and A mixed use with (II-d) is particularly preferred. At least one is preferably trimethylolpropane triacrylate, and the content thereof is preferably 0.5 to 8% by mass relative to the total mass of component A.

In the ink composition of the invention, the content of Component A-2 is 0.1 to 25% by mass, more preferably 0.5 to 10% by mass, and still more preferably 2%, based on the total mass of Component A. -9 mass%.
Within the above range, an ink composition having excellent curability and ejection stability, and excellent cured substrate adhesion and gloss can be obtained.

<Compound represented by formula (II ')>
The ink composition of the second embodiment of the present invention contains at least one compound represented by formula (II ′) as component A-2.
Hereinafter, the compound represented by the formula (II ′) used as Component A-2 of the ink composition of the invention will be described.

（式（II’）中、Ｒ¹¹は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹²は水素原子、又は置換されていてもよい炭素数１〜６のアルキル基を表し、Ｒ¹³はそれぞれ独立に水素原子、又はメチル基を表し、Ｘ²は単結合、又は二価の連結基を表し、ｐ、ｑ及びｒはそれぞれ独立に０〜５の整数を表し、ｐ＋ｑ＋ｒ≧１の関係を満たす。）

(In the formula (II ′), R ¹¹ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and R ¹² represents a hydrogen atom or an optionally substituted carbon atom having 1 to 6 carbon atoms. R ¹³ represents each independently a hydrogen atom or a methyl group, X ² represents a single bond or a divalent linking group, and p, q and r are each independently an integer of 0 to 5 And satisfies the relationship of p + q + r ≧ 1.)

Wherein ^{(II '), R 11,} R 12, R 13, and X ^{2, R 11, R 12, R} 13 in formula (II), and X ² in the above formula, preferred embodiment is also the same . p, q, and r each independently represent an integer of 0 to 5, and satisfy the relationship of p + q + r ≧ 1. p, q and r are each independently preferably 1 to 3, particularly preferably 1 or 2.
Specific examples of the compound when p, q and r have preferred values are (II-a), (II-b), (II) in the compounds exemplified in the preferred embodiment of the compound represented by formula (II). II-c) and the like, but are not limited thereto.

(Component A-1-3) (Meth) acrylate compound having an aromatic hydrocarbon ring The ink composition of the present invention further comprises (Component A-1-3) an aromatic hydrocarbon ring as A-1 (meta ) An acrylate compound can be preferably contained.
Component A-1-3 will be described below.

  As the component A-1-3, an aromatic monofunctional radically polymerizable monomer described in paragraphs 0048 to 0063 of JP-A-2009-96985 is preferably exemplified. In the present invention, the monofunctional (meth) acrylate compound having an aromatic hydrocarbon ring is preferably a compound represented by the formula (a-2).

（式（ａ−２）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、Ａｒは一価の芳香族炭化水素基を表す。）

(In formula (a-2), R ¹ represents a hydrogen atom or a methyl group, X ¹ represents a divalent linking group, and Ar represents a monovalent aromatic hydrocarbon group.)

In formula (a-2), R ¹ is preferably a hydrogen atom.
X ¹ represents a divalent linking group, and is an ether bond (—O—), an ester bond (—C (O) O— or —OC (O) —), an amide bond (—C (O) NR′— or -NR'C (O)-), a carbonyl group (-C (O)-), an imino group (-NR'-), an optionally substituted alkylene group having 1 to 15 carbon atoms, or A divalent group in which two or more of these are combined is preferable. 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. Examples of the substituent include a hydroxy group and a halogen atom.
The moiety containing R ¹ and X ¹ (H ₂ C═C (R ¹ ) —C (O) —X ¹ —) can be bonded at any position on the aromatic hydrocarbon ring. Further, from the viewpoint of improving the affinity with the colorant, the end bonded to the aromatic hydrocarbon ring of X ¹ is preferably an oxygen atom, and more preferably an etheric oxygen atom. X ¹ in formula (a-2) is preferably * —O— (LO) _q —. Here, * shows the coupling | bonding position with the carbonyl group of Formula (a-2), q is an integer of 0-10, L represents a C2-C4 alkylene group. q is preferably an integer of 0 to 4, more preferably an integer of 0 to 2, and even more preferably 1 or 2. (LO) _q is preferably an ethylene oxide chain or a propylene oxide chain.

Ar represents a monovalent aromatic hydrocarbon group.
Examples of the monovalent aromatic hydrocarbon group include monovalent monocyclic or polycyclic aromatic hydrocarbon groups having 1 to 4 rings, such as benzene, naphthalene, anthracene, 1H-indene, One from 9H-fluorene, 1H-phenalene, phenanthrene, triphenylene, pyrene, naphthacene, tetraphenylene, biphenylene, as-indacene, s-indacene, acenaphthylene, fluoranthene, acephenanthrylene, acanthrylene, chrysene, prianden, etc. Examples include a group excluding a hydrogen atom.
Among them, in the present invention, a phenyl group and a naphthyl group are preferable, and a monocyclic aromatic hydrocarbon group, that is, a phenyl group is more preferable.

The monovalent aromatic hydrocarbon group may have a substituent on the aromatic ring.
Examples of the substituent include a halogen atom, an alkyl group, an alkenyl group, a carboxy group, an acyl group having 1 to 10 carbon atoms, a hydroxy group, a substituted or unsubstituted amino group, a thiol group, a siloxane group, or a substituent. It is preferably a hydrocarbon group or heterocyclic group having a total carbon number of 30 or less that may have.
The substituent may further have a substituent, and examples thereof include a hydroxy group, an alkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 12 carbon atoms.
When the monovalent aromatic hydrocarbon group has a plurality of substituents, the substituents may be the same or different. The substituents may be bonded to form a 5-membered or 6-membered ring. The monovalent aromatic hydrocarbon group preferably has no substituent on the aromatic ring.

  In the present invention, the compound represented by the formula (a-2) is preferably a compound having a phenyl group, more preferably 2-phenoxyethyl (meth) acrylate or benzyl (meth) acrylate, and 2-phenoxyethyl ( (Meth) acrylate is more preferred, and 2-phenoxyethyl acrylate (PEA) is particularly preferred.

The content of Component A-1-3 in the ink composition of the present invention is preferably 5 to 40% by mass, more preferably 8 to 30% by mass, based on the total mass of Component A-1.
Within the above range, an ink composition having excellent curability and ejection stability, and excellent cured substrate adhesion and gloss can be obtained.

<Other polymerizable compounds>
The ink composition of the present invention includes components A-1 and A-2, a component A-1-1, a component A-1-2, a component A-1-3, and a compound represented by the formula (II). Other polymerizable compounds other than those may be contained.
The other polymerizable compound is not particularly limited, but an ethylenically unsaturated compound is preferable.
As other polymerizable compounds, known polymerizable compounds can be used, other than the compounds represented by Component A-1-1, Component A-1-2, Component A-1-3, and Formula (II). (Meth) acrylate compounds, vinyl ether compounds, allyl compounds, unsaturated carboxylic acids, and the like. For example, the radically polymerizable monomer described in JP2009-22214A, the polymerizable compound described in JP2009-209289A, and the ethylenically unsaturated compound described in JP2009-191183A can be mentioned.

  The ink composition of the present invention is preferably a bifunctional (meth) acrylate compound other than the compound represented by Component A-1-1, Component A-1-2, Component A-1-3, and Formula (II). Can be used. As the bifunctional (meth) acrylate compound, a bifunctional (meth) acrylate compound having a hydrocarbon chain which may have a branch having 5 or more carbon atoms is preferable.

  Preferable examples of the bifunctional (meth) acrylate compound are bifunctional (meth) acrylate compounds having a hydrocarbon chain having 5 or more carbon atoms in the molecule, specifically, neopentyl glycol di (meth) acrylate, Propylene oxide (PO) modified neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, PO modified hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, decanediol di (meth) acrylate, dodecane Diol di (meth) acrylate, tridecanediol di (meth) acrylate, octadecanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 2-n-butyl-2-ethyl- 1,3-propanedi Ruji (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, and, cyclohexanedimethanol (meth) acrylate. Among these, PO-modified neopentyl glycol di (meth) acrylate is particularly preferable.

  The ink composition of the present invention further comprises a trifunctional or more functional compound as a polymerizable compound other than the compound represented by Component A-1-1, Component A-1-2, Component A-1-3 and Formula (II). A (meth) acrylate compound can also be used. Preferable examples of the tetrafunctional (meth) acrylate compound include pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like.

  Other polyfunctional (meth) acrylates include bis (4- (meth) acryloxypolyethoxyphenyl) propane, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, Examples include tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol diacrylate, and 2,2-bis (4- (meth) acryloxypolyethoxyphenyl) propane.

  Examples of other polymerizable compounds include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and their salts, anhydrides having an ethylenically unsaturated group, Examples include acrylonitrile, styrene, and various radically polymerizable compounds such as various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes.

  Specific examples of other polymerizable compounds include 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, carbitol (meth) acrylate, cyclohexyl (meth) acrylate, benzyl ( (Meth) acrylate, methyl (meth) acrylate, n-butyl (meth) acrylate, allyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminomethyl (meth) acrylate, oligoester (meth) acrylate, N-methylol (meta ) (Meth) acrylic acid derivatives such as acrylamide, diacetone (meth) acrylamide, and epoxy (meth) acrylate, and other ants such as allyl glycidyl ether, diallyl phthalate, and triallyl trimellitate Derivative compounds.

More specifically, Shinzo Yamashita “Cross-linking agent handbook” (1981, Taiseisha); Kato Kiyosumi “UV / EB curing handbook (raw material)” (1985, Polymer publication society); Ed. “Application and Market of UV / EB Curing Technology” on page 79 (1989, CMC Publishing Co., Ltd.); “Polyester Resin Handbook” by Eiichiro Takiyama (1988, Nikkan Kogyo Shimbun) Radical polymerizable or crosslinkable monomers, oligomers and polymers known in the industry can be used.
The molecular weight of the other polymerizable compound is preferably 80 to 2,000, more preferably 80 to 1,000, and still more preferably 80 to 800.

The ink composition of the present invention includes a monofunctional vinyl ether as a polymerizable compound other than the compound represented by Component A-1-1, Component A-1-2, Component A-1-3, and Formula (II). It is also preferable to use a compound.
Examples of the monofunctional vinyl ether compound suitably used include ethylene glycol monovinyl ether, triethylene glycol monovinyl ether, hydroxyethyl monovinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, Examples include 2-ethylhexyl vinyl ether, hydroxynonyl monovinyl ether, cyclohexanedimethanol monovinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, and the like.

  Moreover, a polyfunctional vinyl ether compound can also be used. Suitable polyfunctional vinyl ether compounds include, for example, 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, cyclohexane. Examples thereof include di- or trivinyl ether compounds such as dimethanol divinyl ether and trimethylolpropane trivinyl ether.

  The ink composition of the present invention is a compound represented by Component A-1-1, Component A-1-2, Component A-1-3, and Formula (II) among Components A-1 and A-2. When other polymerizable compounds other than the above are contained, the content of the other polymerizable compounds is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, with respect to the total mass of the polymerizable compound. 30% by mass is particularly preferred.

(Component B) Radical polymerization initiator The ink composition of the present invention comprises (Component B) a radical polymerization initiator. The ink composition ejected on the support is cured by irradiation with actinic radiation. This is because the radical polymerization initiator contained in the ink composition of the present invention is decomposed by irradiation with actinic radiation to generate a polymerization initiation species such as a radical, and the polymerization reaction of the polymerizable compound in the function of the initiation species, This is because it is created and promoted.
The radical polymerization initiator in the present invention is not only a compound that absorbs external energy such as actinic radiation to generate a polymerization initiating species, but also a compound that absorbs a specific active energy ray and promotes decomposition of the polymerization initiator. (So-called sensitizers) are also included. In the ink composition of the present invention, when a sensitizer is present together with a radical polymerization initiator, the sensitizer in the system absorbs actinic radiation to be in an excited state and comes into contact with the radical polymerization initiator, thereby causing the radical polymerization initiator. Decomposition can be promoted, and a more sensitive curing reaction can be achieved. Examples of the sensitizer include those described in JP-A-2008-208190.

The ink composition of the present invention contains, as Component B, (Component B-1) a monoacylphosphine oxide compound and / or (Component B-2) a bisacylphosphine oxide compound, and (Component B-3) a thioxanthone compound. It is preferable to do.
By combining Component B with Component A-1, A-2 and Component C, an ink composition having excellent curability and ejection stability, and excellent cured substrate adhesion and glossiness is obtained. can get.
Hereinafter, Component B-1 to Component B-3 will be described.

(Component B-1) Monoacylphosphine oxide compound (Component B-1) The monoacylphosphine oxide compound is not particularly limited and may be a known one, and is represented by the following formula (b-1). It is preferable that it is a compound.

（式（ｂ−１）中、Ｒ^1D、Ｒ^2D、Ｒ^3Dは、それぞれ独立に、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 (b-1), R ^1D , R ^2D and R ^3D each independently represents an aromatic hydrocarbon group which may have a methyl group or an ethyl group as a substituent.)

As the monoacylphosphine oxide compound represented by the formula (b-1), R ^{1D to} R ^3D are preferably each independently a phenyl group optionally having a methyl group as a substituent. More preferably, ^2D and R ^3D are phenyl groups, and R ^1D is a phenyl group having 1 to 3 methyl groups.
Among these, as the monoacylphosphine oxide compound represented by the formula (b-1), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Darocur TPO: manufactured by Ciba Japan, Lucirin TPO: manufactured by BASF) is preferable. .

  The content of Component B-1 is preferably from 0.1 to 3% by mass, and more preferably from 0.5 to 3% by mass, based on the entire ink composition.

(Component B-2) Bisacylphosphine oxide compound (Component B-2) The bisacylphosphine oxide compound is not particularly limited and may be a known one, and is represented by the following formula (b-2). It is preferable that it is a compound.

（式（ｂ−２）中、Ｒ^1E、Ｒ^2E及びＲ^3Eはそれぞれ独立に、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 (b-2), R ^1E , R ^2E and R ^3E each independently represents an aromatic hydrocarbon group optionally having a methyl group or an ethyl group as a substituent.)

A known compound can be used as the bisacylphosphine oxide compound. Examples thereof include bisacylphosphine oxide compounds described in JP-A-3-101686, JP-A-5-345790, and JP-A-6-298818.
Specific examples include bis (2,6-dichlorobenzoyl) phenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-ethoxy. Phenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2-naphthylphosphine oxide, bis (2,6-dichlorobenzoyl) -1-naphthyl Phosphine oxide, bis (2,6-dichlorobenzoyl) -4-chlorophenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,4-dimethoxyphenylphosphine oxide, bis (2,6-dichlorobenzoyl) decylphosphite Oxide, bis (2,6-dichlorobenzoyl) -4-octylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,5- Dimethylphenylphosphine oxide, bis (2,6-dichloro3,4,5-trimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichloro-3,4,5-trimethoxybenzoyl) -4-ethoxyphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-ethoxyphenylphosphine oxide, bis (2- Methyl-1-naphthoyl) -2-naphthy Phosphine oxide, bis (2-methyl-1-naphthoyl) -4-propylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methoxy-1-naphthoyl) ) -4-Ethoxyphenylphosphine oxide, bis (2-chloro-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, etc. Is mentioned.

  Among these, as the bisacylphosphine oxide compound, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (IRGACURE 819: manufactured by BASF Japan Ltd.), bis (2,6-dimethoxybenzoyl) -2, 4,4-trimethylpentylphosphine oxide and the like are preferable.

  The content of Component B-2 is preferably 0.5 to 10% by mass, and more preferably 1 to 5% by mass, based on the entire ink composition.

(Component B-3) Thioxanthone Compound The ink composition of the present invention can preferably contain (Component B-3) a thioxanthone compound as a polymerization initiator.
There is no restriction | limiting in particular as a thioxanthone compound, Although a well-known thing can be used, It is preferable that it is a compound represented by a following formula (b-3).

In the formula (b-3), R ^1F , R ^2F , R ^3F , R ^4F , R ^5F , R ^6F , R ^7F and R ^8F are each independently a hydrogen atom, alkyl group, halogen atom, hydroxy group, cyano Group, nitro group, amino group, alkylthio group, alkylamino group (including the case of mono- and di-substitution. The same applies to the following), alkoxy group, alkoxycarbonyl group, acyloxy group, acyl group, carboxy group Represents a group or a sulfo group. The number of carbon atoms in the alkyl group, the alkylthio group, the alkylamino group, the alkoxy group, the alkoxycarbonyl group, the acyloxy group, and the alkyl moiety in the acyl group is preferably 1-20, and more preferably 1-8. Preferably, it is 1-4.
R ^1F , R ^2F , R ^3F , R ^4F , R ^5F , R ^6F , R ^7F, and R ^8F may be bonded 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, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2-dodecylthioxanthone, 2,4-dichlorothioxanthone, 2,3-diethylthioxanthone, 1-chloro-4-propoxythioxanthone, 2-cyclohexylthioxanthone, 4-cyclohexylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 1-methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3- (2-methoxyethoxycarbonyl) thioxanthone, 4-butoxy Carbonylthioxanthone, 3-butoxycarbonyl-7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-eth Sicarbonyl-3-chlorothioxanthone, 1-ethoxycarbonyl-3-ethoxythioxanthone, 1-ethoxycarbonyl-3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfylthioxanthone, 3,4-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-methylthioxanthone, thioxanthone- Examples include 2-polyethylene glycol ester, 2-hydroxy-3- (3,4-dimethyl-9-oxo-9H-thioxanthone-2-yloxy) -N, N, N-trimethyl-1-propaneaminium chloride. Among these, thioxanthone, 2,3-diethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-cyclohexylthioxanthone from the viewpoint of availability and curability 4-cyclohexylthioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone are preferable, and 2-isopropylthioxanthone and 4-isopropylthioxanthone are more preferable.

  The content of Component B-3 is preferably 0.5 to 10% by mass and more preferably 1 to 5% by mass with respect to the entire ink composition.

(Component B-4) α-Aminoalkylphenone Compound The ink composition of the invention preferably further contains (Component B-4) an α-aminoalkylphenone compound as Component B. By containing Component B-4, an ink composition having further excellent curability can be obtained. Component B-4 is preferably a compound represented by Formula (b-4).

In formula (b-4), R ¹ , R ² , and R ³ are each independently a hydroxy group, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, or Represents an amino group which may have a substituent, and X represents a hydrogen atom, an amino group which may have a substituent, an alkylthio group which may have a substituent, or a substituent. Represents an optionally substituted alkyl group. At least one of R ¹ , R ² , or R ³ represents an optionally substituted amino group. The substituents in the case where R ¹ , R ² , R ³ and X are amino groups may be bonded to each other to form a heterocyclic group. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms.

  Component B-4 is preferably a compound represented by any one of formula (b-4-1) and formula (b-4-2).

In formula (b-4-1), R ⁴ , R ⁵ , R ⁶ , and R ⁷ each represents an alkyl group that may have a substituent, and R ⁴ and R ⁵ , and R ⁶ and R ^At least one of ⁷ may be bonded to each other to form a heterocyclic group. R < ¹ >, R < ² > and a substituent are respectively synonymous with R < ¹ >, R < ² > and a substituent in Formula (b-4).

In formula (b-4-2), R ⁸ represents an alkyl group which may have a substituent.
R ^1, R ^2, and the substituents, R ^1, R ² in formula (b-4), and has the same meaning as the substituent, R ⁴ and R ^5, in formula (b-4-1) Synonymous with R ⁴ and R ⁵ .
There is no restriction | limiting in particular as said heterocyclic group, Although it can select suitably, For example, a morpholino group is preferable.

  As an alpha-aminoalkylphenone compound, IRGACURE369 (made by BASF Japan), IRGACURE907 (made by BASF Japan), etc. are mentioned suitably as a commercial item, for example.

  The content of Component B-4 is preferably 0.5 to 10% by mass, and more preferably 1 to 5% by mass based on the entire ink composition.

  A preferred embodiment of component B in the present invention is to contain component B-1 and / or B-2 and B-3, more preferably at least component B-1 and the content thereof is ink. It is 3 mass% or less of the composition total mass. It is more preferable that the components B-1, B-3, and B-4 are contained in combination, and it is particularly preferable that the components B-1 to B-3 are contained in combination.

  The total content of component B in the present invention is preferably 1 to 20% by mass of the total ink composition, more preferably 5 to 15% by mass, and still more preferably 8 to 10% by mass. .

The ink composition of the present invention may contain a polymerization initiator other than the polymerization initiators of components B-1 to B-4. Other polymerization initiators include monoacylphosphine compounds, α-hydroxyketone compounds, aromatic ketones, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borates. Examples thereof include compounds, azinium compounds, metallocene compounds, active ester compounds, and compounds having a carbon halogen bond.
Details of the polymerization initiator are known to those skilled in the art, and are described, for example, in paragraphs 0090 to 0116 of JP-A-2009-185186.

(Component C) Colorant The ink composition of the present invention contains (Component C) a colorant.
The component C contributes to improving the visibility of the formed image portion. Although there is no restriction | limiting in particular as Component C, The pigment and oil-soluble dye which were excellent in weather resistance and were rich in color reproducibility are preferable, and can be arbitrarily selected from well-known colorants, such as a soluble dye, and can be used. Component C is preferably selected from 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.
Below, the pigment and dye used as component C are demonstrated.

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 C.I. I. Pigment Red 3 (also referred to as “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, 202, 208, 216, 226, 257, C.I. I. Pigment violet 3 (also referred to as “Pigment Violet 3”), 19, 23, 29, 30, 37, 50, 88, C.I. I. Pigment Orange 13 (also referred to as “Pigment Orange 13”), 16, 20, 36, blue or cyan pigments include C.I. I. Pigment Blue 1 (also referred to as “Pigment Blue 1”), 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17-1, 22, 27, 28, 29, 36, 60, green pigments include C.I. I. Pigment Green 7 (also referred to as “Pigment Green 7”), 26, 36, 50, yellow pigments include C.I. I. Pigment Yellow 1 (also referred to as “Pigment Yellow 1”), 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 120, 137, 138, 139, 150, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193, black pigments include C.I. I. Pigment Black 7 (also referred to as “Pigment Black 7”), 28, 26, and white pigments include C.I. I. Pigment White 6 (also referred to as “Pigment White 6”), 18, 21 or the like can be used depending on the purpose.

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; C.I. 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 etc. are mentioned.

  It is preferable that the colorant is appropriately dispersed in the ink composition after being added to the ink composition. 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. That is, it is preferable not to contain a solvent. In consideration of only dispersibility, it is preferable to select a monomer having the lowest viscosity as the polymerizable compound used for the addition of 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 solid in the ink composition, the average particle diameter of the colorant particles is preferably 0.005 to 0.5 μm, more preferably 0.01 to It is preferable to set the colorant, the dispersant, the dispersion medium, the dispersion conditions, and the filtration conditions so as to be 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 component C in the ink composition is appropriately selected depending on the color and purpose of use, but is preferably 0.1 to 20% by mass with respect to the mass of the entire ink composition, 0.5 to More preferably, it is 10 mass%, and it is still more preferable that it is 1-5 mass%.

<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. The “polymer dispersing agent” in the present invention means a dispersing agent having a weight average molecular weight of 1,000 or more.

Examples of the polymer dispersant include DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-111, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-166, and DISPERBYK-166. , DISPERBYK-168, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, DISPERBYK-182 (manufactured by BYK Chemie); EFKA7462, EFKA7500, EFKA7570, EFKA7575, EFKA7580 (manufactured by Efka Additive); Disperse Aid 6, Disperse Aid 8, Disperse Aid 15, Disperse Aid 9100 (manufactured by Sannopco); Solsperse (SOLSPERSE) 3000 Various Solsperse dispersants (manufactured by Noveon) such as 5000, 9000, 12000, 13240, 13940, 17000, 22000, 24000, 26000, 28000, 32000, 36000, 39000, 41000, 71000; , L61, L64, F68, L72, P95, F77, P84, F87, P94, L101, P103, F108, L121, -123 (manufactured by ADEKA); Ionette S-20 (manufactured by Sanyo Chemical Industries); Disparon KS-860, 873SN, 874 (polymer dispersing agent), # 2150 (aliphatic polycarboxylic acid), # 7004 (polyether 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 mass with respect to the mass of the entire ink composition.

<Surfactant>
The ink composition of the present invention does not contain a silicone-based surfactant and a fluorosurfactant, or the total content of the silicone-based surfactant and the fluorosurfactant is the total mass of the ink composition. On the other hand, it is preferably less than 0.01% by mass, does not contain a silicone-based surfactant and a fluorosurfactant, or is more preferably 0.005% by mass or less, and a silicone-based surfactant. It is particularly preferable that no fluorine-containing surfactant is contained.
Examples of surfactants other than silicone surfactants and fluorine surfactants include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, 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.
Further, the ink composition of the present invention does not contain a surfactant other than the silicone surfactant and the fluorine surfactant, or the content thereof is 0. 0 relative to the total mass of the ink composition. It is preferably less than 01% by mass, not contained, or more preferably 0.005% by mass or less, and particularly preferably not contained.
As a silicone type surfactant which can be obtained with a commercial item, BYK-307 (made by BYK Chemie) is mentioned, for example.

<Oligomer>
The ink composition of the present invention preferably contains an oligomer.
The oligomer is generally a polymer in which a finite number of monomers (generally 5 to 100) are bonded, and a known compound called an oligomer can be arbitrarily selected. It is preferable to select a polymer having a molecular weight of 400 to 10,000 (more preferably 500 to 5,000).
The oligomer may have a radical polymerizable group. As the radical polymerizable group, an ethylenically unsaturated group is preferable, and a (meth) acryloxy group is more preferable.

As the oligomer in the present invention, any oligomer may be used. For example, olefin (ethylene oligomer, propylene oligomer, butene oligomer, etc.), vinyl (styrene oligomer, vinyl alcohol oligomer, vinyl pyrrolidone oligomer, acrylate oligomer, methacrylate oligomer, etc.) , Diene (butadiene oligomer, chloroprene rubber, pentadiene oligomer, etc.), ring-opening polymerization (di-, tri-, tetraethylene glycol, polyethylene glycol, polyethylimine, etc.), polyaddition (oligoester acrylate, polyamide oligomer, Polyisocyanate oligomer), addition condensation oligomer (phenol resin, amino resin, xylene resin, ketone resin, etc.) and the like. In this, oligoester (meth) acrylate is preferable, in which urethane (meth) acrylate, polyester (meth) acrylate, and epoxy (meth) acrylate are more preferable, and urethane (meth) acrylate is still more preferable. Preferred examples of the urethane (meth) acrylate include aliphatic urethane (meth) acrylates and aromatic urethane (meth) acrylates, and more preferred are aliphatic urethane (meth) acrylates.
The urethane (meth) acrylate is preferably a tetrafunctional or lower urethane (meth) acrylate, and more preferably a bifunctional or lower urethane (meth) acrylate.
By containing urethane (meth) acrylate, an ink composition having excellent adhesion to the substrate and excellent curability can be obtained.
Regarding the oligomer, the oligomer handbook (supervised by Junji Furukawa, Chemical Industry Daily Co., Ltd.) can also be referred to.

Moreover, what is shown below can be illustrated as a commercial item of an oligomer.
Examples of the urethane (meth) acrylate include R1204, R1211, R1213, R1217, R1218, R1301, R1302, R1303, R1304, R1306, R1308, R1901, and R1150 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. EBECRYL series (for example, EBECRYL230, 270, 4858, 8402, 8804, 8807, 8803, 9260, 1290, 1290K, 5129, 4842, 8210, 210, 4827, 6700, 4450, 220) manufactured by Co., Ltd. NK oligo U-4HA, U-6HA, U-15HA, U-108A, U200AX, etc. manufactured by Kogyo Co., Ltd., Aronix M-1100, M-1200, M-1210, M-1310 manufactured by Toagosei Co., Ltd. M-1600, M-1960, Sartomer Co. CN964A85, CN962, CN983, and the like.
Examples of the polyester (meth) acrylate include EBECRYL series (for example, EBECRYL770, IRR467, 81, 84, 83, 80, 675, 800, 810, 812, 1657, 1810, IRR302, 450, manufactured by Daicel Cytec Co., Ltd. 670, 830, 870, 1830, 1870, 2870, IRR267, 813, IRR483, 811, etc.), Aronix M-6100, M-6200, M-6250, M-6500, M-7100, manufactured by Toagosei Co., Ltd. , M-8030, M-8060, M-8100, M-8530, M-8560, M-9050 and the like.
Moreover, as an epoxy (meth) acrylate, for example, EBECRYL series (for example, EBECRYL600, 860, 2958, 3411, 3600, 3605, 3700, 3701, 3703, 3702, 3708, RDX63182, 6040 manufactured by Daicel Cytec Co., Ltd. Etc.).

An oligomer may be used individually by 1 type, or may use 2 or more types together.
The content of the oligomer in the ink composition of the present invention is preferably 0.1 to 50% by mass, more preferably 0.5 to 20% by mass with respect to the total mass of the ink composition. More preferably, it is 1-10 mass%.

<Other ingredients>
The ink composition of the present invention contains a co-sensitizer, an ultraviolet absorber, an antioxidant, an anti-fading agent, a conductive salt, a solvent, a basic compound, etc., as necessary, in addition to the above-described components. Also good. As these other components, known components can be used, for example, those described in JP-A-2009-22214.

The ink composition of the present invention preferably contains a polymerization inhibitor from the viewpoint of improving storage stability.
When the ink composition is used as an ink composition for ink jet recording, it is preferably discharged at a temperature in the range of 25 to 80 ° C. with a reduced viscosity, and a polymerization inhibitor is added to prevent head clogging due to thermal polymerization. It is preferable to do.
Examples of the polymerization inhibitor include nitroso polymerization inhibitors, hydroquinone, benzoquinone, p-methoxyphenol, TEMPO, TEMPOL, cuperon Al, hindered amines, etc. Among them, nitroso polymerization inhibitors and hindered amine polymerization inhibitors are preferable.
Specific examples of the nitroso polymerization inhibitor preferably used in the present invention are shown below, but are not limited thereto.

  Examples of commercially available nitroso polymerization inhibitors include FIRSTCURE ST-1 (manufactured by Chem First). Examples of commercially available hindered amine polymerization inhibitors include TINUVIN292, TINUVIN770DF, TINUVIN765, and TINUVIN123.

  The content of the polymerization inhibitor in the ink composition of the present invention is preferably 0.01 to 2% by mass, more preferably 0.1 to 1.5% by mass, and still more preferably 0.2 to 1.2% by mass. . Within the above numerical range, polymerization at the time of preparation and storage of the ink composition can be suppressed, and clogging of the ink jet nozzle can be prevented.

(Inkjet recording method, inkjet recording apparatus and printed matter)
In the inkjet recording method of the present invention, the ink composition of the present invention is ejected onto a recording medium (support, recording material, etc.) for inkjet recording, and actinic radiation (to the ink composition ejected onto the recording medium) This is a method of forming an image by irradiating active energy rays and curing the ink composition.

More specifically, the ink jet recording method of the present invention comprises (a ¹ ) a step of ejecting the ink composition of the present invention onto a recording medium, and (b ¹ ) active energy in the ejected ink composition. It is preferable to include a step of irradiating a line to cure the ink composition.
By including the steps (a ¹ ) and (b ¹ ), the ink jet recording method of the present invention forms an image with the ink composition cured on the recording medium.
The printed matter of the present invention is a printed matter recorded by the inkjet recording method of the present invention.

In the step (a ¹ ) in the ink jet recording method of the present invention, an ink jet recording apparatus described in detail below can be used.

<Inkjet recording apparatus>
There is no restriction | limiting in particular as an inkjet recording device which can be 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 inkjet recording apparatus including a commercially available product can eject the ink composition onto the recording medium in the step (a ¹ ) of the inkjet 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 active energy ray source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head preferably has a multi-size dot of 1 to 100 pl, more preferably 8 to 30 pl, preferably 320 × 320 to 4,000 × 4,000 dpi, more preferably 400 × 400 to 1,600 ×. It can be driven so that it can discharge at a resolution of 1,600 dpi, more preferably 720 × 720 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

  As described above, the ink composition of the present invention is preferably provided with a means for stabilizing the temperature of the ink composition in the ink jet recording apparatus because the ink composition to be ejected is preferably kept at a constant temperature. The parts to be kept at a constant temperature are all the piping systems and members from the ink tank (the intermediate tank if there is an intermediate tank) to the nozzle ejection surface. That is, heat insulation and heating can be performed from the ink 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 at each piping site and perform heating control according to the ink flow rate and the environmental temperature. The temperature sensor can be provided near the ink 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.

Using the above inkjet recording apparatus, the ink composition of the present invention is ejected by heating the ink composition to preferably 25 to 80 ° C., more preferably 25 to 50 ° C. Preferably it is performed after lowering to 3 to 15 mPa · s, more preferably 3 to 13 mPa · s. In particular, it is preferable to use an ink composition having an ink viscosity at 25 ° C. of 50 mPa · s or less as the ink composition of the present invention, since it can be discharged satisfactorily. By using this method, high ejection stability can be realized.
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 temperature control range of the ink composition is preferably set to ± 5 ° C. of the set temperature, more preferably ± 2 ° C. of the set temperature, and further preferably set temperature ± 1 ° C. .

The ink jet head used in the ink jet recording method of the present invention is preferably an ink jet head having a nozzle plate whose surface on the ink ejection side is treated with a parent ink.
An example of an inkjet head having a nozzle plate whose surface on the ink ejection side has been subjected to ink-philic processing is an on-demand inkjet head manufactured by FUJIFILM Dimatix using a piezo drive system. Specific examples thereof include S-class and Q-class Sapphire.

  The nozzle plate may be a nozzle plate whose surface on the ink discharge side has been subjected to parent ink processing, and may be one in which at least a part of the surface on the ink discharge side has been subjected to parent ink processing. Those that have been treated with a parent ink are preferred.

Examples of the method for the ink-philic treatment include a method of forming one or more non-ink-repellent layers on at least a part of the surface of the nozzle plate.
Specifically, the nozzle plate is made of gold, stainless steel, iron, titanium, tantalum, platinum, rhodium, nickel, chromium, silicon oxide, silicon nitride, and aluminum nitride on at least a part of the surface on the ink ejection side. It is preferable to include a layer formed of at least one selected from the group consisting of gold, stainless steel, iron, titanium, silicon oxide, silicon nitride, and aluminum nitride. More preferably, it is more preferable to provide a layer formed of at least one selected from the group consisting of gold, stainless steel and silicon oxide, and most preferable to include a layer formed of silicon oxide.

  A known ink processing method can be used as the parent ink processing method. For example, (1) a method of thermally oxidizing the surface of a silicon nozzle plate to form a silicon oxide film, and (2) silicon or silicon Examples include a method of forming an oxide film other than oxidatively, a method of forming by sputtering, and (3) a method of forming a metal film. For details of these methods, reference can be made to US Patent Application Publication No. 2010/0141709.

Next, the step (b ¹ ) of curing the ink composition by irradiating the discharged ink composition with active energy rays will be described.
The ink composition discharged on the recording medium is cured by irradiating with active energy rays. This is because the polymerization initiator contained in the ink composition of the present invention is decomposed by irradiation with active energy rays to generate polymerization initiation species such as radicals, and the polymerization reaction of the polymerizable compound is a function of the initiation species. This is because it is created and promoted. At this time, if the sensitizer is present together with the polymerization initiator in the ink composition, the sensitizer in the system absorbs the active energy ray to be in an excited state, and the polymerization initiator is decomposed by contact with the polymerization initiator. It can be accelerated 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 active energy rays. Although the peak wavelength of the active energy ray depends on the absorption characteristics of the sensitizer, for example, it is preferably 200 to 600 nm, more preferably 300 to 450 nm, still more preferably 320 to 420 nm, The active energy ray is particularly preferably ultraviolet light having a peak wavelength in the range of 340 to 400 nm.

In addition, the polymerization initiation system of the ink composition of the present invention has sufficient sensitivity even with a low output active energy ray. Therefore, it is appropriate to cure the exposed surface with an illuminance of 10 to 4,000 mW / cm ² , more preferably 20 to 2,500 mW / cm ² .

Mercury lamps, gas / solid lasers, etc. are mainly used as active energy ray sources, and mercury lamps and metal halide lamps are widely used as light sources for curing UV photocurable ink jet recording ink compositions. Are known. 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.
In addition, a light emitting diode (LED) and a laser diode (LD) can be used as an active energy ray 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 launched a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. When even shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit active energy rays centered between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. A particularly preferable active energy ray source in the present invention is a UV-LED, and a UV-LED having a peak wavelength at 340 to 400 nm is particularly preferable.
The maximum illumination intensity of the LED on a recording medium is preferably 10 to 2,000 mW / cm ^2, more preferably 20 to 1,000 mW / cm ^2, at 50 to 800 mW / cm ² It is particularly preferred.

The ink composition of the present invention is suitably irradiated with such active energy rays for 0.01 to 120 seconds, more preferably for 0.1 to 90 seconds.
The irradiation conditions and basic irradiation method of active energy rays 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. The irradiation with the active energy ray is performed for a certain period of time after the ink composition has landed (preferably 0.01 to 0.5 seconds, more preferably 0.01 to 0.3 seconds, and still more preferably 0.01 to 0.15). Seconds). 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 recording medium from spreading before curing. In addition, since the ink composition can be exposed to a porous recording medium before the ink composition penetrates to a deep part where the light source does not reach, it is preferable because residual unreacted monomers can be suppressed.
Furthermore, it 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 recording media 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 highest brightness. By superimposing the ink compositions in order from the 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.
Thus, the ink composition of the present invention can form an image on the surface of a recording medium by being cured with high sensitivity by irradiation with active energy rays.

The ink jet recording method of the present invention preferably uses an ink set.
In the inkjet recording method of the present invention, the order of the colored ink compositions to be ejected is not particularly limited, but it is preferably applied to the recording medium from a colored ink composition having high brightness, and yellow, cyan, When magenta and black are used, it is preferable to apply them on the recording medium in the order of yellow → cyan → magenta → black. In addition, when white is added to this, it is preferable to apply it on the recording medium in the order of white → yellow → cyan → magenta → black. Further, the present invention is not limited to this, and an ink set including at least a total of seven colors including yellow, light cyan, light magenta, cyan, magenta, black, and white ink compositions can be preferably used. In this case, it is preferable to apply white, light cyan, light magenta, yellow, cyan, magenta, and black on the recording medium in this order.

  In the present invention, the recording medium is not particularly limited, and a known recording medium can be used as a support or a recording material. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, propionic acid) Cellulose, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, polyvinyl chloride (PVC), acrylic resin, etc.) A plastic film (composite aluminum plate etc.) etc. are mentioned. Moreover, a non-absorbable recording medium can be suitably used as the recording medium in the present invention.

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, “part” means “part by mass” and “%” means “% by mass” unless otherwise specified.

The materials used in the present invention are as shown below.
・ IRGALITE BLUE GLVO (cyan pigment, manufactured by BASF Japan Ltd.)
・ CINQUASIA MAGENTA RT-355-D (magenta pigment, manufactured by BASF Japan Ltd.)
・ NOVOPERM YELLOW H2G (yellow pigment, manufactured by Clariant)
SPECIAL BLACK 250 (Black pigment, manufactured by BASF Japan Ltd.)
・ SOLSPERSE32000 (dispersant, manufactured by Noveon)
-NVC (V-CAP, N-vinylcaprolactam, manufactured by IS Japan Co., Ltd.)-NVF: N-vinylformamide (Beamset 770, manufactured by Arakawa Chemical Industries, Ltd.)
CTFA (SR531, cyclic trimethylolpropane formal acrylate, containing 5% by weight of trimethylolpropane triacrylate, manufactured by Sartomer) PEA (SR339, phenoxyethyl acrylate, manufactured by Sartomer)
IBOA (SR506, isobornyl acrylate, manufactured by Sartomer)
SR351S (trimethylolpropane triacrylate, manufactured by Sartomer)
SR454 (compound of formula (II-a), manufactured by Sartomer)
SR9020 (compound of formula (II-b), manufactured by Sartomer)
SR9021 (compound of formula (II-c), manufactured by Sartomer)
・ DPGDA (SR508, dipropylene glycol diacrylate, manufactured by Sartomer)
SR9035: Ethylene oxide 15 mol addition trimethylolpropane triacrylate, manufactured by Sartomer)
CN964A85 (oligomer, bifunctional aliphatic urethane acrylate, containing 15% by weight tripropylene glycol diacrylate, manufactured by Sartomer)
CN962 (oligomer, bifunctional aliphatic urethane acrylate, manufactured by Sartomer)
IRGACURE 369 (α-aminoalkylketone photopolymerization initiator, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, manufactured by BASF Japan Ltd.)
IRGACURE 819 (photopolymerization initiator, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, manufactured by BASF Japan Ltd.)
・ TPO (DAROCURE TPO, photopolymerization initiator, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, manufactured by BASF Japan Ltd.)
・ ITX (sensitizer, isopropylthioxanthone, manufactured by Shell Chemicals Japan) ・ ST-1 (FIRSTCURE ST-1, polymerization inhibitor, tris (N-nitroso-N-phenylhydroxyamine) aluminum salt (8% by mass) ) And phenoxyethyl acrylate (92% by mass, manufactured by Chem First)
・ BYK-307 (silicone surfactant, manufactured by BYK Chemie)

(Preparation of magenta mill base)
-Magenta pigment: CINQUASIA MAGENTA RT-355D (manufactured by BASF Japan Ltd.) 30 parts by mass-SR9003 (propoxylated (2) neopentyl glycol propylene oxide 2 mol adduct compound obtained by diacrylate, 49 parts by mass / SOLSPERSE 32000 (dispersing agent, manufactured by Noveon) 20 parts by mass / FIRSTCURE ST-1 (polymerization inhibitor, manufactured by Chem First) 1 part by mass The above components are stirred and mixed to obtain a magenta mill base. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 8 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of cyan mill base)
-Cyan pigment: IRGALITE BLUE GLVO (manufactured by BASF Japan Ltd.) 30 parts by mass-SR9003 49 parts by mass-SOLPERSE32000 20 parts by mass-FIRSTCURE ST-1 1 part by mass The mixture was stirred and mixed to obtain a cyan mill base.

(Preparation of yellow mill base)
Yellow pigment: NOVOPERM YELLOW H2G (manufactured by Clariant)
30 parts by mass, SR9003 29 parts by mass, BYK168 (dispersing agent, manufactured by BYK Chemie) 40 parts by mass, FIRSTCURE ST-1 (polymerization inhibitor, manufactured by Chem First) 1 part by weight The above components are the same as the preparation of magenta mill base The mixture was stirred and mixed under the following dispersion conditions to obtain a yellow mill base.

(Preparation of black mill base)
Black pigment: SPECIAL BLACK 250 (manufactured by BASF Japan Ltd.) 30 parts by mass SR9003 49 parts by mass SOLPERSE32000 20 parts by mass FIRSTCURE ST-1 1 part by mass The above components are dispersed under the same conditions as in the preparation of the magenta mill base. The mixture was stirred and mixed to obtain a black mill base.

(Ink compositions of Examples 1 to 22 and Comparative Examples 1 to 10)
<Method for producing ink composition>
Each ink composition was prepared by mixing and stirring the materials described in Table 1 and Table 2, and inks of Examples 1 to 22 and Comparative Examples 1 to 10 were obtained. In addition, the numerical value in a table | surface represents the compounding quantity (mass part) of each component.

<Inkjet recording method>
Recording was performed on a recording medium using an ink jet recording experimental apparatus having a piezoelectric ink jet nozzle. The ink jet recording apparatus has a total of eight ink supply systems, and each of the ink supply systems is independent of each ink supply system, and includes an original tank, a supply pipe, an ink supply tank immediately before the ink jet head, a filter, and a piezo type. It consists of an inkjet head. The prepared ink was filled in an ink tank, and the ink supply tank to the inkjet head part were insulated and heated.
The eight piezo-type inkjet heads used an inkjet head Q-class Sapphire QS-256 / 10 (manufactured by FUJIFILM DIMATIX, 256 nozzles), arranged in parallel, and 10 to 30 pl multi-size dots are 600 It was simultaneously driven so that it could be ejected at a resolution of × 400 dpi, and printing was performed in a multipass mode in which drawing was performed in 8 passes in bidirectional printing. The printer is equipped with UV-LED lamp light sources (NC4U134, emission wavelength 385 nm, manufactured by Nichia Corporation) on the left and right of the head unit, and 0.05 seconds to 0 when ink landed on the recording medium. .Exposure after 3 seconds. The image is drawn in the multi-pass 8 times bi-directional printing mode. In this case, 16 times of UV exposure is performed on the same portion of the image.

<Evaluation of curability>
A 100% solid image having a film thickness of 12 μm was printed on a polyvinyl chloride sheet by the above printing method. The illuminance on the substrate surface at this time was 0.8 W / cm ² and the exposure amount was 350 mJ / cm ² .
Curing sensitivity was defined by the color transfer on the surface after printing and the exposure energy that eliminates stickiness. The presence or absence of stickiness on the surface after printing was determined by palpation, and color transfer was judged by pressing plain paper (Fuji Xerox Co., Ltd. copy paper C2) immediately after printing. It was evaluated that the sensitivity was so high that there was no color transfer or stickiness, and the following criteria were used. Three or more have no practical problem.
5: No color transfer and no stickiness.
4: No color transfer and almost no stickiness.
3: No color transfer and slightly sticky.
2: There is a slight color shift and slightly stickiness.
1: There is color transfer and stickiness.

<Evaluation of substrate adhesion>
A cross-hatch test (JIS K5600-5-6, 2004) was performed as a method for evaluating adhesion to a polyvinyl chloride substrate. A solid image having an average film thickness of 12 μm was drawn according to the inkjet recording method. Thereafter, a cross-hatch test was performed on each printed matter. In addition, evaluation evaluated and classified into 6 steps of 0-5 according to JISK5600-5-6 (2004). Here, evaluation classification 0 means that the edge of the cut is completely smooth, and there is no peeling in the eyes of any lattice, and evaluation was performed according to the following classification.
When making an incision in the lattice, the evaluation between the ink and the substrate was made by making an incision to the depth reaching the substrate. If it is 3 or more of the following evaluation 1-5, there is no problem practically.
5: JIS K5600-5-6 Classification 0
4: JIS K5600-5-6 Classification 1
3: JIS K5600-5-6 Classification 2
2: JIS K5600-5-6 Classification 3
1: JIS K5600-5-6 Classification 4, 5

<Evaluation of ejection stability>
The obtained ink composition was stored at room temperature (25 ° C.) for 2 weeks, then recorded on a recording medium using the ink jet recording apparatus, and printed continuously at room temperature (25 ° C.) for 3 hours. The presence or absence of ink drop and ink scattering was visually observed and evaluated according to the following criteria.
5: Dot missing or ink bending does not occur.
4: Occurrence of missing dots or ink scattering occurs once or twice.
3: Omission of dots or ink scattering occurs 3 to 4 times.
2: Omission of dots or ink scattering occurs 5 times or more.
1: Dot missing or ink scattering occurs 10 times or more.
A rating of 3 or higher is acceptable in practice.

<Evaluation of glossiness>
A solid image was drawn according to the above-described ink jet recording method, using a special paper made by Mitsubishi Paper Industries (basis weight: 104 g / m2) as a recording medium. The obtained solid image was measured at a measurement angle of 60 ° using a gloss meter manufactured by Sheen Instruments, based on JIS Z8741. Evaluation points were assigned according to the following criteria.
5: Glossiness 25 or more 4: Glossiness 20 or more and less than 25 3: Glossiness 15 or more and less than 20 2: Glossiness 10 or more and less than 15 1: Glossiness 10 or less Evaluation 3 or more is acceptable in practice.

  The above evaluation results are shown in Tables 1 and 2. In addition, "-" in a table | surface represents that the said component is not contained. Moreover, (*) mark in a table | surface means the following. (* 1) represents including the amount of 92 mass% PEA (solvent) contained in ST-1. (* 2) represents that the amount of TMPTA is 5% by mass, which is an impurity in CTF. (* 3) indicates that the amount of SR9003 in each mill base is included.

Claims (8)

(Component A) a radically polymerizable compound, (Component B) a radical polymerization initiator, and (Component C) a colorant,
Component A contains (Component A-1) a monofunctional radically polymerizable compound and (Component A-2) a polyfunctional radically polymerizable compound,
As Component A-1, (Component A-1-1) contains an N-vinyl compound and (Component A-1-2) a compound represented by Formula (I),
The content of Component A-1 is 50 to 90% by mass with respect to the total mass of Component A,
The content of Component A-1-1 is 10 to 40% by mass with respect to the total mass of Component A-1,
The content of component A-1-2 is 5 to 90% by mass relative to the total mass of component A-1,
Component A-2 contains at least two compounds represented by formula (II),
Content of component A-2 is 0.1-25 mass% with respect to the total mass of component A, The inkjet ink composition characterized by the above-mentioned.

(In formula (I), R ¹ , R ² and R ³ each independently represents a hydrogen atom, a methyl group or an ethyl group, and X ¹ represents a single bond or a divalent linking group.)

(In formula (II), each R ¹¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and R ¹² represents a hydrogen atom or an optionally substituted carbon atom 1. Represents an alkyl group of ˜6, R ¹³ independently represents a hydrogen atom or a methyl group, X ² represents a single bond or a divalent linking group, and p, q and r each independently represent 0 to 5 Represents an integer.)   The inkjet ink composition according to claim 1, wherein Component A-1-1 is N-vinylcaprolactam.   The component A-1 further comprises (component A-1-3) a (meth) acrylate compound having an aromatic hydrocarbon ring in an amount of 5 to 40% by mass based on the total mass of the component A-1. The inkjet ink composition according to 2.   The component B contains (Component B-1) a monoacylphosphine oxide compound and / or (Component B-2) a bisacylphosphine oxide compound, and (Component B-3) a thioxanthone compound. The inkjet ink composition according to any one of the above.   The compound according to any one of claims 1 to 4, wherein at least one of the compounds represented by formula (II) is trimethylolpropane triacrylate, and the content thereof is 0.5 to 8% by mass with respect to the total mass of component A. The inkjet ink composition according to Item 1.   6. The component B according to claim 1, comprising (Component B-1) a monoacylphosphine oxide compound as Component B, the content of which is 3% by mass or less based on the total mass of the ink composition. Inkjet ink composition. The inkjet ink composition according to any one of claims 1 to 6, comprising at least one compound represented by formula (II ') as component A-2.

(In the formula (II ′), R ¹¹ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms, and R ¹² represents a hydrogen atom or an optionally substituted carbon atom having 1 to 6 carbon atoms. R ¹³ represents each independently a hydrogen atom or a methyl group, X ² represents a single bond or a divalent linking group, and p, q and r are each independently an integer of 0 to 5 And satisfies the relationship of p + q + r ≧ 1.) (A ¹ ) a step of discharging the ink-jet ink composition according to any one of claims 1 to 7 onto a recording medium; and
(B ¹ ) A step of irradiating the ejected ink-jet ink composition with actinic radiation to cure the ink-jet ink composition.