JP2008208189A - Ink composition, ink set, ink-jet recording method and printed material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ink composition having an excellent surface tack-free property, blocking resistance of cured film, water resistance, solvent resistance and adhesivity to a plastic substrate and to provide an ink set using the ink composition, an ink-jet recording method and a printed material. <P>SOLUTION: The ink composition comprises ≥50 wt.% of the total of a monomer represented by formula (I) and/or formula (II) (wherein R<SP>1</SP>is a hydrogen atom, a halogen atom or a 1-4C alkyl group; X<SP>1</SP>is a difunctional connecting group; R<SP>2</SP>and R<SP>3</SP>are each independently a substituent group; k is an integer of 1-6; q and r are each independently an integer of 0-5; and n is a cyclic hydrocarbon structure) in the ink composition. The ink set, the ink-jet recording method and the printed material each use the ink composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink composition, an ink set, an ink jet recording method which are suitably used for ink jet recording, and a printed matter obtained using the ink composition.

As an image recording method for forming an image on a recording medium such as paper based on an image data signal, there are an electrophotographic method, a sublimation type and a melt type thermal transfer method, an ink jet method and the like. The electrophotographic system requires a process of forming an electrostatic latent image on a photosensitive drum by charging and exposure, and there is a problem that the system becomes complicated and consequently the manufacturing cost becomes high. In addition, although the thermal transfer system is inexpensive, there are problems such as high running costs and waste materials due to the use of ink ribbons.
On the other hand, the ink jet method is an inexpensive device and ejects ink only to a required image portion to form an image directly on a recording medium, so that the ink composition can be used efficiently and the running cost is low. . Furthermore, there is little noise and it is excellent as an image recording method.

  As an ink composition that can be cured by irradiation with radiation such as ultraviolet rays, particularly as an ink composition for ink jet recording (radiation curable ink composition for ink jet recording), surface tack-free property, blocking resistance of a cured film, water resistance, There is a need for ink compositions that are excellent in solvent resistance and adhesion to plastic substrates.

As an ink composition, an ink composition containing N-vinyl lactams is disclosed (Patent Document 1). However, the ink composition described in Patent Document 1 is a high-viscosity ink composition containing a polymer or oligomer as a main component of the ink composition, and it is difficult to perform inkjet discharge.
In addition, the ink composition that can be cured by irradiation with radiation such as ultraviolet rays includes (a) an oligo / resin component; (b) (i) a pendant alkoxylated functionality and no main chain alkoxylated functionality. About 10 to about 10 weight percent, comprising 0.1 to 50 weight percent adhesion promoting radiation curable component comprising one or more heterocyclic radiation curable monomers and / or alkoxylated monomers; and (ii) backbone alkoxylated functionality. An ink composition is disclosed that includes a radiation curable reactive diluent that includes up to a percent of an optional alkoxylated radiation curable monomer (US Pat. No. 6,057,049).
Patent Document 3 discloses an ink jet comprising an acrylate monomer having a dicyclopentenyl group, an N-vinyl lactam monomer, another photopolymerizable compound, a photopolymerization initiator, and a colorant. Ink for use is described.

Japanese Patent No. 2880845 JP-T-2004-514014 JP 2006-299117 A

  An object of the present invention is to provide an ink composition excellent in surface tack-free property, blocking resistance of a cured film, water resistance, solvent resistance, and adhesion to a plastic substrate, and an ink set using the ink composition, An inkjet recording method and a printed matter are provided.

The above object has been achieved by the means described in <1>, <5> and <7> below. It is shown below with <2>-<4> and <6> which are preferable embodiments.
<1> an ink composition comprising a total of 50% by weight or more of monomers represented by formula (I) and / or formula (II),

（式（I）及び式（II）中、Ｒ¹は水素原子、ハロゲン原子、又は、炭素数１〜４のアルキル基を表し、Ｘ¹は二価の連結基を表し、Ｒ²及びＲ³はそれぞれ独立に置換基を表し、ｋは１〜６の整数を表し、ｑ及びｒはそれぞれ独立に０〜５の整数を表し、ｎは環状炭化水素構造を表し、前記環状炭化水素構造として炭化水素結合以外にカルボニル結合（−Ｃ（Ｏ）−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）を含んでいてもよく、ｋ個存在するＲ¹、ｋ個存在するＸ¹、ｑ個存在するＲ²、及び、ｒ個存在するＲ³はそれぞれ同じであっても、異なっていてもよく、また、式（I）におけるアダマンタン骨格中の一炭素原子をカルボニル結合（−Ｃ（Ｏ）−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）で置換してもよく、式（II）におけるノルボルネン骨格中の一炭素原子をエーテル結合（−Ｏ−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）で置換してもよい。）
＜２＞ 式（I）又は式（II）で表されるモノマーのうち少なくとも１つが単官能アクリレートである上記＜１＞に記載のインク組成物、
＜３＞ 前記式（II）で表されるモノマーが式（III）、式（IV）又は式（V）で表されるモノマーである上記＜１＞又は＜２＞に記載のインク組成物、

(In Formula (I) and Formula (II), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, R ² and R ³ Each independently represents a substituent, k represents an integer of 1 to 6, q and r each independently represents an integer of 0 to 5, n represents a cyclic hydrocarbon structure, and carbonized as the cyclic hydrocarbon structure In addition to a hydrogen bond, a carbonyl bond (—C (O) —) and / or an ester bond (—C (O) O—) may be included, k existing R ¹ , k existing X ¹ , q R ² present and R ³ present may be the same or different, and one carbon atom in the adamantane skeleton in the formula (I) is bonded to a carbonyl bond (—C (O )-) And / or an ester bond (—C (O) O—) One carbon atom in the rubornene skeleton may be substituted with an ether bond (—O—) and / or an ester bond (—C (O) O—).
<2> The ink composition according to <1>, wherein at least one of the monomers represented by the formula (I) or the formula (II) is a monofunctional acrylate,
<3> The ink composition according to <1> or <2>, wherein the monomer represented by the formula (II) is a monomer represented by the formula (III), the formula (IV), or the formula (V).

（式（III）、式（IV）及び式（V）中、Ｒ¹は水素原子、ハロゲン原子、又は、炭素数１〜４のアルキル基を表し、Ｘ¹は二価の連結基を表し、Ｒ⁴、Ｒ⁵及びＲ⁶はそれぞれ独立に置換基を表し、ｋは１〜６の整数を表し、ｓ、ｔ及びｕはそれぞれ独立に０〜５の整数を表し、また、ｓ個存在するＲ⁴、ｔ個存在するＲ⁵、及び、ｕ個存在するＲ⁶はそれぞれ同じであっても、異なっていてもよい。）
＜４＞ インクジェット記録用である上記＜１＞〜＜３＞のいずれか１つに記載のインク組成物、
＜５＞ シアン色、マゼンタ色、イエロー色、ブラック色、ホワイト色、ライトマゼンタ色、ライトシアン色及びライトブラック色よりなる群から選択される上記＜１＞〜＜４＞のいずれか１つに記載のインク組成物を２つ以上含むインクセット。
＜６＞ （ａ¹）被記録媒体上に、上記＜１＞〜＜４＞のいずれか１つに記載のインク組成物を吐出する工程、及び、（ｂ¹）吐出されたインク組成物に活性放射線を照射して、該インク組成物を硬化する工程、を含むインクジェット記録方法、
＜７＞ 前記活性放射線が、３５０〜４２０ｎｍの範囲に発光ピーク波長を有し、且つ、被記録媒体表面での最高照度が１０〜２，０００ｍＷ／ｃｍ²である発光ダイオードにより照射される上記＜６＞に記載のインクジェット記録方法、
＜８＞ 上記＜６＞又は＜７＞に記載のインクジェット記録方法によって記録された印刷物。

(In Formula (III), Formula (IV) and Formula (V), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, R ⁴ , R ⁵ and R ⁶ each independently represent a substituent, k represents an integer of 1 to 6, s, t and u each independently represents an integer of 0 to 5, and s are present. R ⁴ , R ⁵ present in t, and R ⁶ present in u may be the same or different.
<4> The ink composition according to any one of <1> to <3>, which is for inkjet recording.
<5> Any one of the above items <1> to <4> selected from the group consisting of cyan, magenta, yellow, black, white, light magenta, light cyan and light black An ink set comprising two or more ink compositions.
<6> (a ¹ ) A step of discharging the ink composition according to any one of the above <1> to <4> on a recording medium, and (b ¹ ) the discharged ink composition Irradiating actinic radiation to cure the ink composition, an inkjet recording method comprising:
<7> The above-mentioned actinic radiation is irradiated by a light emitting diode having an emission peak wavelength in a range of 350 to 420 nm and a maximum illuminance on a recording medium surface of 10 to 2,000 mW / cm ² <6>, an ink jet recording method,
<8> A printed matter recorded by the inkjet recording method according to <6> or <7>.

  According to the present invention, an ink composition excellent in surface tack-free property, blocking resistance of a cured film, water resistance, solvent resistance, and adhesion to a plastic substrate, and an ink set using the ink composition, An ink jet recording method and a printed material can be provided.

(1) Ink composition The ink composition of the present invention (hereinafter, also simply referred to as “ink”) has a total of 50 weight% of monomers represented by formula (I) and / or formula (II) in the ink composition. % Or more.

（式（I）及び式（II）中、Ｒ¹は水素原子、ハロゲン原子、又は、炭素数１〜４のアルキル基を表し、Ｘ¹は二価の連結基を表し、Ｒ²及びＲ³はそれぞれ独立に置換基を表し、ｋは１〜６の整数を表し、ｑ及びｒはそれぞれ独立に０〜５の整数を表し、ｎは環状炭化水素構造を表し、前記環状炭化水素構造として炭化水素結合以外にカルボニル結合（−Ｃ（Ｏ）−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）を含んでいてもよく、ｋ個存在するＲ¹、ｋ個存在するＸ¹、ｑ個存在するＲ²、及び、ｒ個存在するＲ³はそれぞれ同じであっても、異なっていてもよく、また、式（I）におけるアダマンタン骨格中の一炭素原子をカルボニル結合（−Ｃ（Ｏ）−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）で置換してもよく、式（II）におけるノルボルネン骨格中の一炭素原子をエーテル結合（−Ｏ−）及び／又はエステル結合（−Ｃ（Ｏ）Ｏ−）で置換してもよい。）
また、本発明のインク組成物は、Ｎ−ビニル化合物を含有することが好ましい。
以下、本発明について詳細に説明する。

(In Formula (I) and Formula (II), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, R ² and R ³ Each independently represents a substituent, k represents an integer of 1 to 6, q and r each independently represents an integer of 0 to 5, n represents a cyclic hydrocarbon structure, and carbonized as the cyclic hydrocarbon structure In addition to a hydrogen bond, a carbonyl bond (—C (O) —) and / or an ester bond (—C (O) O—) may be included, k existing R ¹ , k existing X ¹ , q R ² present and R ³ present may be the same or different, and one carbon atom in the adamantane skeleton in the formula (I) is bonded to a carbonyl bond (—C (O )-) And / or an ester bond (—C (O) O—) One carbon atom in the rubornene skeleton may be substituted with an ether bond (—O—) and / or an ester bond (—C (O) O—).
The ink composition of the present invention preferably contains an N-vinyl compound.
Hereinafter, the present invention will be described in detail.

  The “radiation” as used in the present invention is not particularly limited as long as it is an actinic radiation that can impart energy capable of generating an initial species in the ink composition by irradiation, and widely includes α rays, γ rays, X Among these, ultraviolet rays and electron beams are preferable, and ultraviolet rays and electron beams are particularly preferable from the viewpoints of curing sensitivity and device availability. Therefore, the ink composition of the present invention is preferably an ink composition that can be cured by irradiating ultraviolet rays as radiation.

(A) Monomer represented by formula (I) or formula (II) The ink composition of the present invention comprises a monomer represented by the formula (I) and / or formula (II) (hereinafter referred to as component (A)). In the ink composition in a total of 50% by weight or more. Preferably it is 54 weight% or more, More preferably, it is 60 weight% or more, Preferably it is 90 weight% or less, More preferably, it is 75 weight% or less. A combination of these lower limit value and upper limit value is also preferable.
By containing a total of 50% by weight or more of the monomers represented by the above formula (I) and / or formula (II), surface hardening, blocking resistance of the cured film, water resistance, solvent resistance, and plastic substrate An ink composition having excellent adhesion can be obtained.
Although it is not clear as to why the above effect is manifested, the hydrophobic polycyclic ring structure possessed by the monomer represented by formula (I) or (II) reduces the surface energy of the film after curing. It is conceivable that the film is oriented on the outermost surface. Since the polycyclic ring structure is a rigid structure, it is presumed that the glass transition temperature (Tg) of the outermost surface of the cured film is improved and a tack-free cured film is obtained. Further, it is presumed that a cured film that hardly causes transfer can be obtained even if the support is stacked on the cured film and stored. Further, since the outermost surface of the cured film becomes hydrophobic, it is presumed that an ink composition having excellent water resistance and solvent resistance can be obtained. When a plastic substrate is used for the support, the affinity between the support and the cured film is obtained by orienting the polycyclic ring structure group toward the hydrophobic plastic substrate at the interface between the cured film and the plastic substrate. It is estimated that it improves and is excellent in the plastic substrate adhesiveness of a cured film.

The ink composition of the present invention may contain only one of the monomer represented by the formula (I) or the monomer represented by the formula (II), and is represented by the formula (I). Both the monomer and the monomer represented by the formula (II) may be contained. Further, two or more monomers represented by the formula (I) may be contained, and two or more monomers represented by the formula (II) may be contained.
The monomer represented by the formula (I) or the formula (II) is preferably an addition polymerizable monomer, and more preferably a radical polymerizable monomer.

R ¹ in formula (I) or formula (II) represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, and from the viewpoint of easy availability of raw materials, a hydrogen atom or 1 to 4 carbon atoms. Are preferably alkyl groups, more preferably hydrogen atoms or methyl groups. The k R ^{1 s} may be the same or different.
X ¹ in formula (I) or formula (II) represents a divalent linking group, and is an ether group (—O—), an ester group (—C (O) O— or —OC (O) —), an amide group. (—C (O) NR′—), a carbonyl group (—C (O) —), a nitrogen atom (—NR′—), an optionally substituted alkylene group having 1 to 15 carbon atoms, or The divalent group is a combination of two or more of these. 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. The k X ^{1 s} may be the same or different.
Further, the end that binds to the vinyl group of X ¹ in Formula (I) or Formula (II) is preferably an ester group or in which the carbonyl carbon and a vinyl group X ¹ binds is an amide group, in which case, The other part of X ¹ bonded to the adamantane skeleton or norbornene skeleton may be a single bond or may be arbitrarily selected from the above groups.
The substitution number k of the vinyl moiety (H ₂ C═C (R ¹ ) —X ¹ —) containing R ¹ and X ¹ in Formula (I) or Formula (II) represents an integer of 1 to 6. The vinyl moiety containing R ¹ and X ¹ can be attached at any position on each alicyclic hydrocarbon structure. Note that “on each alicyclic hydrocarbon structure” refers to the adamantane structure in formula (I), the norbornene structure in formula (II), and the cyclic hydrocarbon structure including n.
Further, from the viewpoint of improving the affinity with the colorant, the end bonded to the alicyclic hydrocarbon structure of X ¹ in formula (I) or formula (II) is preferably an oxygen atom, It is more preferable that X ¹ in formula (I) or formula (II) is —C (O) O (CH ₂ CH ₂ O) p— (p represents 1 or 2). More preferably.

R ² and R ³ in formula (I) or formula (II) each independently represent a substituent, and can be bonded at any position on each alicyclic hydrocarbon structure. Further, q R ^{2 s} and r R ^{3 s} may be the same or different.
R ² present in q and R ³ present in r may each independently be a monovalent or polyvalent substituent, and as a monovalent substituent, a hydrogen atom, a hydroxyl group, substituted or unsubstituted An amino group, a thiol group, a siloxane group, a hydrocarbon group or heterocyclic group having a total carbon number of 30 or less which may have a substituent, or an oxy group (= O) as a divalent substituent. It is preferable.
The substitution number q of R ² represents an integer of 0 to 5, and the substitution number r of R ³ represents an integer of 0 to 5.

N in the formula (II) represents a cyclic hydrocarbon structure, and both ends thereof may be substituted at any position of the norbornene skeleton, and may be a monocyclic structure or a polycyclic structure. In addition to the hydrocarbon bond, the cyclic hydrocarbon structure may contain a carbonyl bond (—C (O) —) and / or an ester bond (—C (O) O—).
Further, one carbon atom in the adamantane skeleton in the formula (I) may be substituted with a carbonyl bond (—C (O) —) and / or an ester bond (—C (O) O—). One carbon atom in the norbornene skeleton may be substituted with an ether bond (—O—) and / or an ester bond (—C (O) O—).

  The monomer represented by the formula (I) or the formula (II) is preferably a monomer represented by the formula (III), the formula (IV) or the formula (V).

（式（III）、式（IV）及び式（V）中、Ｒ¹は水素原子、ハロゲン原子、又は、炭素数１〜４のアルキル基を表し、Ｘ¹は二価の連結基を表し、Ｒ⁴、Ｒ⁵及びＲ⁶はそれぞれ独立に置換基を表し、ｋは１〜６の整数を表し、ｓ、ｔ及びｕはそれぞれ独立に０〜５の整数を表し、また、ｓ個存在するＲ⁴、ｔ個存在するＲ⁵、及び、ｕ個存在するＲ⁶はそれぞれ同じであっても、異なっていてもよい。）

(In Formula (III), Formula (IV) and Formula (V), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, R ⁴ , R ⁵ and R ⁶ each independently represent a substituent, k represents an integer of 1 to 6, s, t and u each independently represents an integer of 0 to 5, and s are present. R ⁴ , R ⁵ present in t, and R ⁶ present in u may be the same or different.

Formula ^{(III), R 1, X} 1 and k in the formula (IV) or formula (V) has the same meaning as R ^1, X ¹ and k in Formula (I) or Formula (II), preferable ranges are also the same It is.
The vinyl moiety containing R ¹ and X ¹ in formula (III), formula (IV) or formula (V) is the alicyclic hydrocarbon shown below in formula (III), formula (IV) or formula (V). Bonds can be made at any position on the structure.

R ⁴ , R ⁵ and R ⁶ in formula (III), formula (IV) or formula (V) each independently represent a substituent, and each of the above fats in formula (III), formula (IV) or formula (V) The bond can be made at any position on the cyclic hydrocarbon structure. The substituents in R ⁴ , R ⁵ and R ^{6 have} the same meanings as those in R ² and R ³ in formula (I) or formula (II), and the preferred ranges are also the same.
In the formula (III), formula (IV) or formula (V), s, t and u each independently represents an integer of 0 to 5, and s R ^{4 s} , t R ^{5 s} , and The u ⁶ R ^{6 s} may be the same or different.

As the monomer represented by formula (I) or formula (II), preferred specific examples of monofunctional acrylates are shown below.
In some of the following exemplary compounds, the hydrocarbon chain is described by a simplified structural formula in which the symbols of carbon (C) and hydrogen (H) are omitted.

  As the monomer represented by formula (I) or formula (II), preferred specific examples of monofunctional methacrylate are shown below.

  As the monomer represented by formula (I) or formula (II), preferred specific examples of monofunctional acrylamide are shown below.

  As the monomer represented by formula (I) or formula (II), preferred specific examples of monofunctional vinyl ethers are shown below.

  Preferred specific examples of the polyfunctional acrylate represented by the formula (I) or the formula (II) are shown below.

  Preferred specific examples of the polyfunctional methacrylate represented by the formula (II) are shown below.

  Among these monofunctional monomers and polyfunctional monomers, M-1, M-10, M-11, M are the monomers represented by formula (I) or formula (II) in the ink composition of the present invention. It is particularly preferable to use -12, M-13, M-16, or M-35.

The “monofunctional acrylate” in the present invention means a compound having only one acryloxy group, and there is no limitation on having a group other than an acryloxy group, for example, an unsaturated group other than an acryloxy group. You may have a bond. Moreover, it is preferable that a monofunctional acrylate does not have a methacryloxy group, a (meth) acrylamide group, and a vinyloxy group.
Similarly, “monofunctional methacrylate”, “monofunctional acrylamide”, and “monofunctional vinyl ether” mean that each compound has only one such group, and there are no restrictions on having a group other than the group. Absent.
Similarly, “polyfunctional acrylate” and “polyfunctional methacrylate” mean compounds each having two or more of the groups, and there is no limitation on having a group other than the groups.
The monofunctional methacrylate, monofunctional acrylamide, monofunctional vinyl ether, polyfunctional acrylate, and polyfunctional methacrylate are (meth) acryloxy group, (meth) acrylamide group, and vinyloxy group. Of these, it is preferable not to have a group other than the group.

  Of the monomers represented by formula (I) or formula (II) in the ink composition of the present invention, at least one is preferably a monofunctional monomer, and at least one is a monofunctional acrylate. It is more preferable. It is preferable to use a monofunctional monomer because sufficient cured film flexibility can be obtained in addition to sufficient curability.

  When the ink composition of the present invention has a monofunctional acrylate, monofunctional methacrylate, monofunctional acrylamide, or monofunctional vinyl ether represented by the formula (I) or (II), the monofunctional acrylate, monofunctional methacrylate, The proportion of the functional acrylamide and monofunctional vinyl ether in the ink composition is preferably 50 to 90% by weight, more preferably 54 to 90% by weight, and still more preferably 54 to 75% by weight. . Within the above range, the surface tack-free property, the blocking resistance of the cured film, the water resistance, the solvent resistance, and the adhesion to the plastic substrate are excellent, and the viscosity is appropriate.

  When the ink composition of the present invention has a monomer having two or more functional groups selected from acrylate, methacrylate and acrylamide represented by formula (I) or formula (II), the monomer is contained in the ink composition. It is preferable that it is 0.5 to 15 weight%, It is more preferable that it is 0.5 to 10 weight%, It is further more preferable that it is 0.5 to 5 weight%. Within the above range, the curability and flexibility are excellent, and the viscosity is appropriate, which is preferable.

  The proportion of the polyfunctional acrylate having at least two or more acrylate groups in the ink composition of the present invention is preferably 0 to 15% by weight, more preferably 0 to 10% by weight, and further preferably 0 to 5% by weight. . Within the above range, an ink composition excellent in flexibility of a cured film can be provided.

(B) N-Vinyl Compound The ink composition of the present invention preferably contains an N-vinyl compound (hereinafter also referred to as component (B)), and more preferably contains 10% by weight or more.
Examples of the N-vinyl compound include N-vinyl amides, N-vinyl carbazole, N-vinyl imidazole and the like.
Examples of N-vinylamides include compounds such as N-vinyllactams, N-vinylacetamide, N-vinylformamide, N-methyl-N-vinylacetamide, and N-methyl-N-vinylformamide.

The ink composition of the present invention preferably contains N-vinyl lactams, and more preferably contains 10% by weight or more of N-vinyl lactams.
Preferable examples of N-vinyl lactams that can be used in the present invention include compounds represented by the following formula (B-1).

In formula (B-1), n represents an integer of 1 to 5, and n is 2 from the viewpoints of flexibility after the ink composition is cured, adhesion to a recording medium, and availability of raw materials. It is preferably an integer of ˜4, more preferably n is 2 or 4, and particularly preferably n is 4, that is, N-vinylcaprolactam. N-vinylcaprolactam is preferable because it is excellent in safety, is generally available and can be obtained at a relatively low price, and provides particularly good ink curability and adhesion of a cured film to a recording medium.
The N-vinyl lactams may have a substituent such as an alkyl group or an aryl group on the lactam ring, and may be linked with a saturated or unsaturated ring structure.

The ink composition of the present invention preferably contains 10% by weight or more of N-vinyl lactam, more preferably 10% by weight or more and 40% by weight or less, and more preferably 10% by weight or more and 30% by weight or less. It is more preferable that it is 12 wt% or more and 25 wt% or less. When the amount of N-vinyl lactam used is in the above range, the curability, the cured film flexibility, and the substrate adhesion of the cured film are excellent.
N-vinyl lactams are compounds having a relatively high melting point. When the content of N-vinyl lactam is 40% by weight or less, good solubility is exhibited even at a low temperature of 0 ° C. or less, and the temperature range in which the ink composition can be handled is widened.
The N-vinyl lactams may be contained in the ink composition alone or in a plurality of kinds.

(C) Radical polymerization initiator The ink composition of the present invention contains (C) a radical polymerization initiator.
As the polymerization initiator that can be used in the present invention, a known radical polymerization initiator can be used. The radical polymerization initiator that can be used in the present invention may be used alone or in combination of two or more. Moreover, you may use together a radical polymerization initiator and the cationic polymerization initiator mentioned later.
The radical polymerization initiator that can be used in the ink composition of the present invention is a compound that absorbs external energy to generate radical polymerization initiating species. External energy used for initiating polymerization is roughly divided into heat and actinic radiation, and a thermal polymerization initiator and a photopolymerization initiator are used, respectively. Examples of the active radiation include γ rays, β rays, electron beams, ultraviolet rays, visible rays, and infrared rays.

  The radical polymerization initiator that can be used in the present invention includes (a) aromatic ketones, (b) acylphosphine compounds, (c) aromatic onium salt compounds, (d) organic peroxides, and (e) thio compounds. (F) hexaarylbiimidazole compound, (g) ketoxime ester compound, (h) borate compound, (i) azinium compound, (j) metallocene compound, (k) active ester compound, (l) carbon halogen bond And (m) an alkylamine compound. These radical polymerization initiators may use the above compounds (a) to (m) alone or in combination. The radical polymerization initiator in the present invention is preferably used alone or in combination of two or more.

  Preferred examples of (a) aromatic ketones, (b) acylphosphine compounds, and (e) thio compounds include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” P. FOUASSIER J.M. F. RABEK (1993), pp. Examples include compounds having a benzophenone skeleton or a thioxanthone skeleton described in 77-117. More preferable examples include α-thiobenzophenone compounds described in JP-B-47-6416, benzoin ether compounds described in JP-B-47-3981, α-substituted benzoin compounds described in JP-B-47-22326, Benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, dialkoxybenzophenones described in JP-B-60-26483, JP-B-60-26403, JP-A Benzoin ethers described in JP-A-62-81345, JP-B-1-34242, US Pat. No. 4,318,791, α-aminobenzophenones described in European Patent 0284561A1, JP-A-2-21152 P-Di (dimethylaminobenzoyl) benze Thio-substituted aromatic ketones described in JP-A-61-194062, acylphosphine sulfides described in JP-B-2-9597, acylphosphines described in JP-B-2-9596, and JP-B-63-61950 Thioxanthones, and coumarins described in JP-B-59-42864.

  (C) As aromatic onium salt compounds, elements of Groups 15, 16 and 17 of the periodic table, specifically N, P, As, Sb, Bi, O, S, Se, Te, or I fragrances Group onium salts are included. For example, iodonium salts described in European Patent No. 104143, US Pat. No. 4,837,124, Japanese Patent Laid-Open No. 2-150848, Japanese Patent Laid-Open No. 2-96514, European Patent Nos. 370693, 233567, and 297443 are disclosed. The diazonium salts described in the specifications of U.S. Pat. Nos. 2,974,279, 279210, and 422570, U.S. Pat. Nos. 3,902,144, 4,933,377, 4,760013, 4,734,344, and 2,833,827 Benzenediazonium which may have a substituent), diazonium salt resins (formaldehyde resin of diazodiphenylamine, etc.), N-alkoxypyridinium salts, etc. (for example, US Pat. No. 4,743,528, JP-A-63) -138345, JP-A-63 142345, JP-A-63-142346, and JP-B-46-42363, specifically 1-methoxy-4-phenylpyridinium tetrafluoroborate, etc. The compounds described in JP-A 52-147277, 52-14278, and 52-14279 are preferably used. Generates radicals and acids as active species.

  (D) The organic peroxide includes almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. Examples thereof include 3,3 ′, 4,4′-tetra (t -Butylperoxycarbonyl) benzophenone, 3,3 ', 4,4'-tetra (t-amylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (t-octylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (cumylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′- Peroxyester compounds such as tetra (p-isopropylcumylperoxycarbonyl) benzophenone and di-t-butyldiperoxyisophthalate are preferred. .

  (F) Examples of hexaarylbiimidazole compounds include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) ) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (m-methoxyphenyl) biimidazole, 2 , 2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5 ' Tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 Examples include ', 5,5'-tetraphenylbiimidazole.

  (G) Examples of the ketoxime ester compound include 3-benzoyloxyiminobutane-2-one, 3-acetoxyiminobutane-2-one, 3-propionyloxyiminobutane-2-one, and 2-acetoxyiminopentane-3. -One, 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3-p-toluenesulfonyloxyiminotan-2-one, 2-ethoxy And carbonyloxyimino-1-phenylpropan-1-one.

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

  (I) Examples of azinium salt compounds include JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, and JP-B-46-42363. The compound group which has NO bond of each gazette description can be mentioned.

  (J) Examples of metallocene compounds include titanocenes described in JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, and JP-A-2-4705. Examples thereof include iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109.

  Specific examples of the titanocene compound include dichlorobis (cyclopentadienyl) titanium, bis (cyclopentadienyl) bis (phenyl) titanium, bis (cyclopentadienyl) bis (2,3,4,5,6- Pentafluorophen-1-yl) titanium, bis (cyclopentadienyl) bis (2,3,5,6-tetrafluorophen-1-yl) titanium, bis (cyclopentadienyl) bis (2,4,4) 6-trifluorophen-1-yl) titanium, bis (cyclopentadienyl) bis (2,6-difluorophen-1-yl) titanium, bis (cyclopentadienyl) bis (2,4-difluoropheny- 1-yl) titanium, bis (methylcyclopentadienyl) bis (2,3,4,5,6-pentafluoropheny 1-yl) titanium, bis (methylcyclopentadienyl) bis (2,3,5,6-tetrafluorophen-1-yl) titanium, bis (methylcyclopentadienyl) bis (2,4-difluoropheny) -1-yl) titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (pyridin-1-yl) phenyl] titanium, bis (cyclopentadienyl) bis [2,6-difluoro- And 3- (methylsulfonamido) phenyl] titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (N-butylbialoyl-amino) phenyl] titanium, and the like.

  (K) Examples of the active ester compound include the specifications of European Patent Nos. 0290750, 046083, 156153, 271851, and 0388343, U.S. Pat. Nos. 3,901,710, and 4,181,531. Nitrobenzol ester compounds described in JP-A-60-198538 and JP-A-53-133022, European Patents 0199672, 84515, 199672, 0441115, and 0101122. No. 4,618,564, U.S. Pat. No. 4,371,605, and U.S. Pat. No. 4,431,774, JP-A 64-18143, JP-A 2-245756, and JP-A-4-365048. Iminosulfonate compound, Japanese Examined Patent Publication No. 62-6223, Japanese Examined Publication No. 63 No. 14340, and compounds, and the like described in the JP-A No. 59-174831.

  (L) Preferable examples of the compound having a carbon halogen bond include, for example, compounds described in Wakabayashi et al., Bull. Chem. Soc. Japan, 42, 2924 (1969), compounds described in British Patent No. 1388492, Examples thereof include compounds described in Japanese Utility Model Publication No. 53-133428, compounds described in German Patent No. 3337024, and the like.

  Further, compounds described in J. Org. Chem., 29, 1527 (1964) by FC Schaefer et al., Compounds described in JP-A-62-258241, compounds described in JP-A-5-281728, and the like can be mentioned. it can. A compound as described in German Patent No. 2641100, a compound described in German Patent No. 3333450, a compound group described in German Patent No. 3021590, or a compound group described in German Patent No. 3021599, etc. Can be mentioned.

In the ink composition of the present invention, the total use amount of the radical polymerization initiator is based on the total use amount of the N-vinyl compound and the polymerizable compound containing the monomer represented by formula (I) or formula (II). Preferably it is 0.01 to 35 weight%, More preferably, it is 0.5 to 20 weight%, More preferably, it is the range of 1.0 to 15 weight%. The ink composition can be cured at 0.01% by weight or more, and a cured film having a uniform degree of curing can be obtained at 35% by weight or less.
Further, when using the sensitizer described later in the ink composition of the present invention, the total amount of radical polymerization initiator used is preferably a radical polymerization initiator: sensitizer weight ratio with respect to the sensitizer. The range is 200: 1 to 1: 200, more preferably 50: 1 to 1:50, and still more preferably 20: 1 to 1: 5.

(D) Colorant The ink composition of the present invention may contain a colorant as necessary.
The colorant that can be used in the present invention is not particularly limited, but pigments and oil-soluble dyes that are excellent in weather resistance and excellent in color reproducibility are preferable, and are arbitrarily selected from known colorants such as soluble dyes. Can be used. The colorant that can be suitably used in the ink composition of the present invention or the ink composition for inkjet recording functions as a polymerization inhibitor in a polymerization reaction that is a curing reaction from the viewpoint of not reducing the sensitivity of the curing reaction by actinic radiation. It is preferred to select compounds that do not.

<Pigment>
Although it does not necessarily limit as a pigment which can be used for this invention, For example, the organic or inorganic pigment of the following number described in a color index can be used.
Examples of red or magenta pigments include Pigment Red 3, 5, 19, 22, 31, 38, 42, 43, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49: 1, 53. : 1, 57: 1, 57: 2, 58: 4, 63: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 88, 104, 108, 112, 122, 123, 144 , 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange 13, 16, 20, 36,
Pigment Blue 1,15,15: 1,15: 2,15: 3,15: 4,15: 6,16,17-1,22,27,28,29,36,60 as a blue or cyan pigment ,
As a green pigment, Pigment Green 7, 26, 36, 50,
As yellow pigments, 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, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193,
As the black pigment, Pigment Black 7, 28, 26,
As a white pigment, Pigment White 6, 18, 21
Etc. can be used according to the purpose.

<Oil-soluble dye>
Below, the oil-soluble dye which can be used by this invention is demonstrated.
The oil-soluble dye that can be used in the present invention means a dye that is substantially insoluble in water. Specifically, the solubility in water at 25 ° C. (the weight of the dye that can be dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. Accordingly, the oil-soluble dye means a so-called water-insoluble pigment or oil-soluble dye, and among these, an oil-soluble dye is preferable.

  Among the oil-soluble dyes that can be used in the present invention, any yellow dye can be used. For example, phenols, naphthols, anilines, pyrazolones, pyridones, aryl or heteryl azo dyes having open-chain active methylene compounds as coupling components; for example, azomethine dyes having open-chain active methylene compounds as coupling components; Examples include methine dyes such as benzylidene dyes and monomethine oxonol dyes; quinone dyes such as naphthoquinone dyes and anthraquinone dyes; and other dye species such as quinophthalone dyes, nitro / nitroso dyes, and acridines. And dyes and acridinone dyes.

  Of the oil-soluble dyes usable in the present invention, any magenta dye can be used. For example, aryl or heteryl azo dyes having phenols, naphthols, anilines as coupling components; for example, azomethine dyes having pyrazolones, pyrazolotriazoles as coupling components; for example arylidene dyes, styryl dyes, merocyanine dyes, oxonol dyes Methine dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes; quinone dyes such as naphthoquinone, anthraquinone, anthrapyridone; condensed polycyclic dyes such as dioxazine dyes, etc. Can be mentioned.

  Among the oil-soluble dyes applicable to the present invention, any cyan dye can be used. For example, indoaniline dyes, indophenol dyes or azomethine dyes having pyrrolotriazoles as coupling components; polymethine dyes such as cyanine dyes, oxonol dyes, merocyanine dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes Phthalocyanine dyes; anthraquinone dyes; for example, aryl or heteryl azo dyes having phenols, naphthols and anilines as coupling components; indigo / thioindigo dyes;

  Each of the above dyes may exhibit yellow, magenta, and cyan colors only after a part of chromophore (chromogenic atomic group) is dissociated. In this case, the counter cation may be an alkali metal or ammonium. Such inorganic cations may be used, and organic cations such as pyridinium and quaternary ammonium salts may be used, and furthermore, polymer cations having such a partial structure may be used.

Although not limited to the following, preferred specific examples include C.I. I. Solvent Black 3, 7, 27, 29 and 34; C.I. I. Solvent Yellow 14, 16, 19, 29, 30, 56, 82, 93 and 162; C.I. I. Solvent Red 1, 3, 8, 18, 24, 27, 43, 49, 51, 72, 73, 109, 122, 132 and 218; I. Solvent Violet 3; C.I. I. Solvent Blue 2,11,25,35,38,67 and 70; I. Solvent Green 3 and 7; I. Solvent orange 2; and the like.
Particularly preferred among these are: Nubian Black PC-0850, Oil Black HBB, Oil Yellow 129, Oil Yellow 105, Oil Pink 312, Oil Red 5B, Oil Scallet 308, Vali Fast Blue chemistry 2606e B2 (Manufactured by Co., Ltd.), Aizen Spiron Blue GNH (manufactured by Hodogaya Chemical Co., Ltd.), Neopen Yellow 075, Neopen Magenta SE1378, Neopen Blue 808, Neopen Blue FF4012, and Neo42 Cy FF4012.
In the present invention, the oil-soluble dye may be used alone or in combination of several kinds.

Moreover, when using an oil-soluble dye as a colorant, other water-soluble dyes, disperse dyes, pigments, and other colorants can be used in combination as long as the effects of the present invention are not impaired.
In the present invention, a disperse dye can be used as long as it is soluble in a water-immiscible organic solvent. The disperse dye generally includes a water-soluble dye, but in the present invention, the disperse dye is preferably used as long as it is soluble in a water-immiscible organic solvent. Preferable specific examples of the disperse dye include C.I. I. Disperse Yellow 5,42,54,64,79,82,83,93,99,100,119,122,124,126,160,184: 1,186,198,199,201,204,224 and 237 C. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54, 55, 66, 73, 118, 119 and 163; I. Disperse Red 54, 60, 72, 73, 86, 88, 91, 92, 93, 111, 126, 127, 134, 135, 143, 145, 152, 153, 154, 159, 164, 167: 1,177 , 181, 204, 206, 207, 221, 239, 240, 258, 277, 278, 283, 311, 323, 343, 348, 356 and 362; I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 165, 165: 1, 165: 2, 176, 183, 185, 197, 198, 201, 214, 224, 225 , 257, 266, 267, 287, 354, 358, 365 and 368; I. Disperse Green 6: 1 and 9;

  It is preferable that the colorant that can be used in the present invention is appropriately dispersed in the ink after being added to the ink composition of the present invention or the ink composition for inkjet recording. 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.

In preparing the ink composition of the present invention, the colorant may be added by directly adding it together with the respective components. It can also be added after being uniformly dispersed or dissolved.
In the present invention, in order to avoid the problem of 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 a radical polymerizable compound. It is preferable to add and mix in advance in such a dispersion medium. 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.

  These colorants may be used by appropriately selecting one type or two or more types 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 of the present invention, the average particle diameter of the colorant particles is preferably 0.005 to 0.5 μm, more preferably 0. It is preferable to set the colorant, the dispersant, the dispersion medium, the dispersion conditions, and the filtration conditions so that the thickness is 0.01 to 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 ink storage stability, ink transparency, and curing sensitivity can be maintained.
The content of the colorant in the ink composition of the present invention is appropriately selected depending on the color and purpose of use, but is preferably 0.01 to 30% by weight based on the total weight of the ink composition.

(E) Dispersant It is preferable to add a dispersant when dispersing the colorant. The type of the dispersant is not particularly limited, but a polymer dispersant is preferably used.
Dispersor BYK-101, DisperBYK-102, DisperBYK-103, DisperBYK-106, DisperBYK-111, DisperBYK-161, DisperBYK-162, DisperBYK-164D, DisperBYK-164D, , DisperBYK-168, DisperBYK-170, DisperBYK-171, DisperBYK-174, DisperBYK-182 (manufactured by BYK Chemie), EFKA4010, EFKA4046, EFKA5080, EFKA5504, EFKA5504, EFKA5504, 62, polymer dispersing agents such as EFKA7500, EFKA7570, EFKA7575, EFKA7580 (manufactured by Fuka Additive), Disperse Aid 6, Disperse Aid 8, Disperse Aid 15, Disperse Aid 9100 (San Nopco); Solsperse) 3000, 5000, 9000, 12000, 13240, 13940, 17000, 24000, 26000, 28000, 32000, 36000, 39000, 41000, 71000, etc. (Abyssia); Adeka Pluronic L31, F38, L42, L44, L61, L64, F68, L72, P95, F77, P84, F87, P94, L101, P103, F108, L121, P-123 ( Manufactured by Denka Co., Ltd.) and Isonet S-20 (manufactured by Sanyo Chemical Co., Ltd.), “Disparon KS-860, 873SN, 874 (polymer dispersant), # 2150 (aliphatic polycarboxylic acid), # 7004 (polyether ester type) ”.
In addition, pigment derivatives such as a phthalocyanine derivative (trade name: EFKA-745 (manufactured by Efka)), Solsperse 5000, 12000, Solsperse 22000 (manufactured by Avicia) can also be used.
The content of the dispersant in the ink composition of the present invention is appropriately selected depending on the purpose of use, but is preferably 0.01 to 5% by weight with respect to the weight of the whole ink composition.

(F) Surfactant It is preferable to add a surfactant to the ink composition of the present invention in order to impart stable discharge properties for a long time.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as 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, an organic fluoro compound or a polysiloxane compound may be used as the surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compounds include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). No. (columns 8 to 17) and those described in JP-A Nos. 62-135826. The polysiloxane compound is preferably a modified polysiloxane compound in which an organic group is introduced into part of the methyl group of dimethylpolysiloxane. Examples of modification include polyether modification, methylstyrene modification, alcohol modification, alkyl modification, aralkyl modification, fatty acid ester modification, epoxy modification, amine modification, amino modification, mercapto modification, etc. is not. These modification methods may be used in combination. Of these, polyether-modified polysiloxane compounds are preferred from the viewpoint of improving ejection stability in inkjet. Examples of the polyether-modified polysiloxane compound include, for example, SILWET L-7604, SILWET L-7607N, SILWET FZ-2104, SILWET FZ-2161 (manufactured by Nippon Unicar Co., Ltd.), BYK-306, BYK-307, BYK- 331, BYK-333, BYK-347, BYK-348, etc. (manufactured by Big Chemie Japan Co., Ltd.), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945 , KF-640, KF-642, KF-643, KF-6020, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (Shin-Etsu Chemical Co., Ltd.) Manufactured).
The content of the surfactant in the ink composition of the present invention is appropriately selected depending on the purpose of use, but generally it is preferably 0.0001 to 1% by weight with respect to the total weight of the ink composition. . These sea surface active agents may be contained alone or in combination of two or more polysiloxane compounds.

(G) Other radical polymerizable compound In the present invention, in addition to the components (A) and (B), other radical polymerizable compounds (hereinafter also simply referred to as “radical polymerizable compounds”, (A), (B ) Needless to say, it means a radically polymerizable compound excluding the component.
Use of a radically polymerizable compound in combination is preferable because an ink composition having further excellent curability can be provided.
Examples of the radical polymerizable compound are described in JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, JP-A-10-863, JP-A-9-80675, and the like. A photocurable material using a photopolymerizable composition is known.

  The radical polymerizable compound is a compound having an ethylenically unsaturated bond capable of radical polymerization, and may be any compound as long as it has at least one ethylenically unsaturated bond capable of radical polymerization in the molecule. , Oligomers, polymers and the like having a chemical form. The radical polymerizable compound may contain one kind at an arbitrary ratio in order to improve the desired properties, and may contain two or more kinds.

Examples of the polymerizable compound having an ethylenically unsaturated bond capable of radical polymerization include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, and salts thereof, Saturated anhydrides, acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, unsaturated urethane (meth) acrylic monomers or prepolymers, epoxy monomers or prepolymers, urethane monomers Alternatively, a (meth) acrylic ester such as a prepolymer is preferably used.
Specific examples include (poly) ethylene glycol mono (meth) acrylate, (poly) ethylene glycol (meth) acrylate methyl ester, (poly) ethylene glycol (meth) acrylate ethyl ester, (poly) ethylene glycol (meth) acrylate phenyl Ester, (poly) propylene glycol mono (meth) acrylate, (poly) propylene glycol mono (meth) acrylate phenyl ester, (poly) propylene glycol (meth) acrylate methyl ester, (poly) propylene glycol (meth) acrylate ethyl ester, Neopentyl glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) tetramethylene glycol di (meth) acrylate, (poly Tetramethylene glycol di (meth) acrylate, bisphenol A propylene oxide (PO) adduct di (meth) acrylate, ethoxylated neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, ethylene oxide (EO) addition of bisphenol A Di (meth) acrylate, EO-modified pentaerythritol triacrylate, PO-modified pentaerythritol triacrylate, EO-modified pentaerythritol tetraacrylate, PO-modified pentaerythritol tetraacrylate, EO-modified dipentaerythritol tetraacrylate, PO-modified dipentaerythritol tetraacrylate , EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane Acrylate, EO-modified tetramethylol methane tetraacrylate, PO-modified tetramethylol methane tetraacrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, n-decyl acrylate, isooctyl acrylate, n-lauryl acrylate, n-tri Decyl acrylate, n-cetyl acrylate, n-stearyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, trimethylolpropane Triacrylate, tetramethylol methane tetraacrylate Acrylate derivatives such as rate, oligoester acrylate, N-methylol acrylamide, diacetone acrylamide, epoxy acrylate, methyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, n-decyl methacrylate , Isooctyl methacrylate, n-lauryl methacrylate, n-tridecyl methacrylate, n-cetyl methacrylate, n-stearyl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, trimethylolethane trimethacrylate, trimethylolpropane tri Methacrylate, 2,2-bis (4-methacryloxypolyethylene Methacryl derivatives such as xylphenyl) propane, other derivatives of allyl compounds such as allyl glycidyl ether, diallyl phthalate, triallyl trimellitate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10 -Decanediol diacrylate, 2-ethylhexyl-diglycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxybutyl acrylate, hydroxypivalate neopentyl glycol diacrylate, 2-acryloyloxyethylphthalic acid, tetramethylol Methane triacrylate, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, dimethylol tricyclodecane diacrylate, ethoxylated phenyl acrylate 2-acryloyloxyethyl succinic acid, modified glycerin triacrylate, bisphenol A diglycidyl ether acrylic acid adduct, modified bisphenol A diacrylate, 2-acryloyloxyethyl hexahydrophthalic acid, dipentaerythritol hexaacrylate, pentaerythritol tri Acrylate tolylene diisocyanate urethane prepolymer, lactone-modified flexible acrylate, butoxyethyl acrylate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, 2-hydroxyethyl acrylate, methoxydipropylene glycol acrylate, ditrimethylolpropane tetraacrylate, pentaerythritol Triacrylate hexamethylene diisocyanate Examples include urethane prepolymers. More specifically, Shinzo Yamashita “Cross-linking agent handbook” (1981, Taiseisha); Kato Kiyosumi “UV / EB curing handbook (raw material)” (1985, polymer) Published by Radtech Research Group, “Application and Market of UV / EB Curing Technology”, page 79 (1989, CMC); described in “Polyester Resin Handbook” by Eiichiro Takiyama (1988, Nikkan Kogyo Shimbun) Commercially available products or radically polymerizable or crosslinkable monomers, oligomers and polymers known in the industry can be used.

Furthermore, it is also preferable to use a vinyl ether compound as the radical polymerizable compound. Suitable vinyl ether compounds include, for example, ethylene glycol divinyl ether, ethylene glycol monovinyl ether, diethylene glycol divinyl ether, triethylene glycol monovinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol. Di- or trivinyl ether compounds such as divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, hydroxyethyl monovinyl ether, hydroxynonyl monovinyl ether, trimethylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octade Examples include monovinyl ether compounds such as ruvinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexanedimethanol monovinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether. It is done.
Of these vinyl ether compounds, divinyl ether compounds and trivinyl ether compounds are preferable from the viewpoints of curability, adhesion, and surface hardness, and divinyl ether compounds are particularly preferable. A vinyl ether compound may be used individually by 1 type, and may be used in combination of 2 or more type as appropriate.

  In the present invention, the monomers listed as the polymerizable compound described above have high reactivity, low viscosity, and excellent adhesion to a recording medium.

  The preferred content of the other radical polymerizable compound in the ink composition is in the range of 1% by weight to 70% by weight, and more preferably in the range of 1% by weight to 60% by weight.

  In the present invention, oligomers and polymers can be used together. Here, an oligomer means a compound having a molecular weight (weight average molecular weight for those having a molecular weight distribution) of 2,000 or more, and a polymer has a molecular weight (weight average molecular weight for those having a molecular weight distribution) of 10. Means more than 1,000 compounds. The oligomer or polymer may or may not have a radical polymerizable group. When the radically polymerizable group in one molecule of the oligomer or polymer is 4 or less (in terms of a compound having a molecular weight distribution, the average of the total number of molecules contained is 4 or less), an ink composition having excellent flexibility can be obtained. preferable. It can also be preferably used in the sense that the viscosity of the ink is adjusted to an optimum viscosity for jetting.

(H) Other components Other components than the above components can be added to the ink composition of the present invention, if necessary.
Examples of other components include sensitizers, co-sensitizers, other polymerizable compounds, other polymerization initiators, ultraviolet absorbers, antioxidants, antifading agents, conductive salts, solvents, and polymer compounds. And basic compounds.

<Sensitizer>
A sensitizer may be added to the ink composition of the present invention to absorb specific actinic radiation and promote decomposition of the polymerization initiator, particularly when used for ink jet recording. The sensitizer absorbs specific actinic radiation and enters an electronically excited state. The sensitizer in an electronically excited state comes into contact with the polymerization initiator, and effects such as electron transfer, energy transfer, and heat generation occur. As a result, the polymerization initiator undergoes a chemical change and decomposes to generate radicals, acids or bases.
As a sensitizer that can be used in the present invention, a sensitizing dye is preferable.
Examples of preferred sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region.
Polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thiacarbocyanine, oxacarbocyanine), merocyanines ( For example, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, anthraquinone), squalium (eg, squalium) ), Coumarins (eg, 7-diethylamino-4-methylcoumarin).

  More preferable examples of the sensitizing dye include compounds represented by the following formulas (IX) to (XIII).

In the formula (IX), A ¹ represents a sulfur atom or NR ⁵⁰ , R ⁵⁰ represents an alkyl group or an aryl group, and L ² forms a basic nucleus of the dye together with the adjacent A ¹ and the adjacent carbon atom. R ⁵¹ and R ⁵² each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁵¹ and R ⁵² may be bonded to each other to form an acidic nucleus of the dye. Good. W represents an oxygen atom or a sulfur atom.

In formula (X), Ar ¹ and Ar ² each independently represent an aryl group and are linked via a bond with —L ³ —. Here, L ³ represents —O— or —S—. W is synonymous with that shown in Formula (IX).

In the formula (XI), A ₂ represents a sulfur atom or NR ⁵⁹ , L ⁴ represents a nonmetallic atomic group that forms a basic nucleus of the dye together with adjacent A ₂ and a carbon atom, R ⁵³ , R ⁵⁴ , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ and R ⁵⁸ each independently represents a monovalent nonmetallic atomic group, and R ⁵⁹ represents an alkyl group or an aryl group.

In formula (XII), A ³ and A ⁴ each independently represent —S—, —NR ⁶² — or —NR ⁶³ —, wherein R ⁶² and R ⁶³ each independently represent a substituted or unsubstituted alkyl group, substituted or Represents an unsubstituted aryl group, and L ⁵ and L ⁶ each independently represent a nonmetallic atomic group that forms a basic nucleus of a dye in combination with adjacent A ³ , A ^4, and adjacent carbon atoms, and R ⁶⁰ , R ⁶¹ each independently represents a hydrogen atom or a monovalent non-metallic atomic group, or may be bonded to each other to form an aliphatic or aromatic ring.

In the formula (XIII), R ⁶⁶ represents an aromatic ring or a hetero ring which may have a substituent, and A ⁵ represents an oxygen atom, a sulfur atom or ═NR ⁶⁷ . R ⁶⁴ , R ⁶⁵ and R ⁶⁷ each independently represent a hydrogen atom or a monovalent non-metallic atomic group; R ⁶⁷ and R ⁶⁴ , and R ⁶⁵ and R ⁶⁷ each represent an aliphatic or aromatic ring. Can be combined to form.

Preferable specific examples of the compounds represented by formulas (IX) to (XIII) include (E-1) to (E-20) shown below.
In some of the following exemplary compounds, the hydrocarbon chain is described by a simplified structural formula in which the symbols of carbon (C) and hydrogen (H) are omitted.

  The content of the sensitizer in the ink composition of the present invention is appropriately selected depending on the purpose of use, but generally it is preferably 0.05 to 4% by weight based on the weight of the whole ink composition. .

<Co-sensitizer>
The ink composition of the present invention preferably contains a co-sensitizer. In the present invention, the co-sensitizer has functions such as further improving the sensitivity of the sensitizer to actinic radiation or suppressing polymerization inhibition of the polymerizable compound by oxygen.
Examples of such co-sensitizers include amines such as MR Sander et al., "Journal of Polymer Society", Vol. 10, p. Publication, JP 52-134692, JP 59-138205, JP 60-84305, JP 62-18537, JP 64-33104, Research Disclosure 33825 Specific examples thereof include triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

  Other examples of co-sensitizers include thiols and sulfides such as thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142772, No. 56-75643, such as 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercapto. And naphthalene.

Other examples include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in Japanese Patent Publication No. 48-42965 (eg, tributyltin acetate), and hydrogen described in Japanese Patent Publication No. 55-34414. Donors, sulfur compounds described in JP-A-6-308727 (eg, trithiane), phosphorus compounds described in JP-A-6-250387 (diethyl phosphite, etc.), Si-- described in JP-A-8-54735 H, Ge-H compound, etc. are mentioned.
The content of the co-sensitizer in the ink composition of the present invention is appropriately selected depending on the purpose of use, but is preferably 0.05 to 4% by weight with respect to the weight of the entire ink composition.

<Other polymerizable compounds>
In the ink composition of the present invention, a cationically polymerizable compound can be used in combination as another polymerizable compound as necessary. When a cationic polymerizable compound is used in combination, a cationic polymerization initiator is also preferably used as a polymerization initiator.
The cationically polymerizable compound that can be used in the present invention is not particularly limited as long as it is a compound that initiates a polymerization reaction with an acid generated from a photoacid generator and cures. Cationic polymerizable monomers can be used. Examples of the cationic polymerizable monomer include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and 2001-2001. Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like described in each publication such as No. 220526.

  In addition, as the cationic polymerizable compound, for example, a polymerizable compound applied to a cationic polymerization type photocurable resin is known, and recently, a photo cationic polymerization type sensitized in a visible light wavelength region of 400 nm or more. Examples of the polymerizable compound applied to the photocurable resin are disclosed in JP-A-6-43633 and JP-A-8-324137. These can also be applied to the ink composition of the present invention.

<Other polymerization initiators>
In the ink composition of the present invention, a cationic polymerization initiator can be used as another polymerization initiator, if necessary. When a cationic polymerization initiator is used in combination, a cationic polymerizable compound is also preferably used as the polymerizable compound.

As cationic polymerization initiators that can be used in the present invention, first, B (C ₆ F ₅ ) ₄ ⁻ , PF ₆ ⁻ , AsF ₆ of aromatic onium compounds such as diazonium, ammonium, iodonium, sulfonium, phosphonium and the like are used. ^- , SbF ₆ ^- and CF ₃ SO ₃ ^- salts. Secondly, sulfonated products that generate sulfonic acid can be mentioned. Thirdly, a halide that generates hydrogen halide can also be used. Fourthly, an iron allene complex can be mentioned.

  Examples of cationic polymerization initiators [(b-1) to (b-96)] suitably used in the present invention are listed below, but the present invention is not limited thereto. In some of the chemical structural formulas in the present invention, the hydrocarbon chain is described by a simplified structural formula in which symbols of carbon (C) and hydrogen (H) are omitted.

<Ultraviolet absorber>
In the present invention, an ultraviolet absorber can be used from the viewpoint of improving the weather resistance of the obtained image and preventing discoloration.
Examples of the ultraviolet absorber are described in JP-A Nos. 58-185677, 61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194433, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492 and 56-21141 Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP No. 8-501291, etc. Triazine compounds, Research Disclosure No. Examples thereof include compounds described in US Pat. No. 24239, stilbene-based and benzoxazole-based compounds that absorb ultraviolet rays and emit fluorescence, so-called fluorescent brighteners.
The addition amount is appropriately selected according to the purpose, but is preferably 0.5 to 15% by weight in terms of solid content.

<Antioxidant>
An antioxidant can be added to improve the stability of the ink composition. Examples of the antioxidant include European published patents, 223739, 309401, 309402, 310551, 310552, 359416, and 3435443. JP, 54-85535, 62-262417, 63-113536, 63-163351, JP-A-2-262654, JP-A-2-71262, Examples thereof include those described in Kaihei 3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275, and the like.
Although the addition amount is appropriately selected according to the purpose, it is preferably 0.1 to 8% by weight in terms of solid content.

<Anti-fading agent>
In the ink composition of the present invention, various organic and metal complex anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. Examples of the metal complex-based antifading agent include nickel complexes and zinc complexes. No. 17643, VII, I to J, No. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544 at page 527, ibid. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .
Although the addition amount is appropriately selected according to the purpose, it is preferably 0.1 to 8% by weight in terms of solid content.

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

<Solvent>
In order to improve the adhesion to the recording medium, it is also effective to add a very small amount of an organic solvent to the ink composition of the present invention.
As the solvent that can be used in the ink composition of the present invention, when a resin is used for the internal structure of the polymerizable particles, the solubility parameter value (SP value) of the resin and the solubility parameter value of the solvent to be used are The difference is preferably 2 or more, and more preferably 3 or more.
Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, and tert-butanol, and chlorine such as chloroform and methylene chloride. Solvents, aromatic solvents such as benzene and toluene, ester solvents such as ethyl acetate, butyl acetate and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, glycols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether Examples include ether solvents.
In this case, it is effective to add the solvent within a range that does not cause the problem of solvent resistance and VOC, and the amount is preferably 0.1 to 5% by weight, more preferably 0.1 to 3% by weight with respect to the whole ink composition. % Range.

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

<Basic compound>
The basic compound is preferably added from the viewpoint of improving the storage stability of the ink composition. As the basic compound that can be used in the present invention, known basic compounds can be used. For example, basic inorganic compounds such as inorganic salts, and basic organic compounds such as amines can be preferably used. .

In addition to this, if necessary, for example, leveling additives, matting agents, waxes for adjusting film physical properties, polymerization to inhibit the adhesion to recording media such as polyolefin and PET, and the like, The tackifier which does not do can be contained.
As a tackifier, specifically, a high molecular weight adhesive polymer (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms) described in JP-A-2001-49200, 5-6p. An ester with an alcohol having, an ester of (meth) acrylic acid and an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer comprising an ester of (meth) acrylic acid and an aromatic alcohol having 6 to 14 carbon atoms) And a low molecular weight tackifier resin having a polymerizable unsaturated bond.

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

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

The ink composition of the present invention is also preferably used as an ink set in which two or more ink compositions of the present invention are combined in order to obtain a desired image.
The ink set of the present invention is not particularly limited as long as it is an ink set in which two or more ink compositions are combined. However, cyan, magenta, yellow, black, white, light magenta, light cyan It is preferable to include two or more ink compositions of the present invention selected from the group consisting of color and light black color.
In order to obtain a full-color image using the ink composition of the present invention, an ink set including at least the four-color ink composition of the present invention consisting of yellow, cyan, magenta and black is used as the ink set of the present invention. It is more preferable to use an ink set containing at least the five-color ink composition of the present invention consisting of yellow, cyan, magenta, black, and white, and cyan, light cyan, magenta, light magenta, black, light It is more preferable to use at least an ink set of the ink composition of the present invention having eight colors consisting of black (gray), white and yellow.

(2) Inkjet recording method, inkjet recording apparatus and printed matter The ink composition of the present invention is used for inkjet recording.
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 is applied to the ink composition ejected onto the recording medium. It is a method of forming an image by irradiating and curing the ink.

More specifically, the inkjet 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 ) actinic radiation on the ejected ink composition. And a step of curing 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 device]
There is no restriction | limiting in particular as an inkjet recording device used for the inkjet recording method of this invention, The well-known inkjet recording device which can achieve the target resolution can be selected arbitrarily and can be used. That is, any known inkjet recording apparatus including a commercially available product can eject ink onto a 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 actinic radiation source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head is preferably 1-100 pl, more preferably 8-30 pl multi-size dots, 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, since it is desirable that the radiation-curable ink, like the ink composition of the present invention, has a constant temperature for the ink to be ejected, heat insulation and heating are performed from the ink supply tank to the inkjet head portion. It can be carried out. The temperature control method is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors in each piping portion and perform heating control according to the ink flow rate and the environmental temperature. The temperature sensor can be provided in the vicinity of 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 usually used in ink jet recording inks, and therefore has a large viscosity fluctuation due to temperature fluctuations during ejection. The ink viscosity fluctuation has a great influence on the change of the droplet size and the change of the droplet discharge speed, and causes the image quality deterioration. Therefore, it is necessary to keep the temperature of the ink at the time of ejection as constant as possible. Therefore, in the present invention, the control range of the ink temperature is preferably set to ± 5 ° C. of the set temperature, more preferably ± 2 ° C. of the set temperature, and further preferably set to ± 1 ° C.

Next, (b ¹ ) a step of curing the ink composition by irradiating the discharged ink composition with actinic radiation will be described.
The ink composition ejected on the recording medium is cured by irradiation with actinic radiation. This is because the polymerization initiator contained in the ink composition of the present invention is decomposed by irradiation with actinic radiation to generate radicals, acids, bases, and other starting species, and the function of the starting species is polymerization of a radical polymerizable compound. This is because the reaction occurs and is promoted. At this time, if a sensitizer is present together with the polymerization initiator in the ink composition, the sensitizer in the system absorbs actinic radiation to be in an excited state, and promotes decomposition of the polymerization initiator by contacting with the polymerization initiator. And a more sensitive curing reaction can be achieved.

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

In addition, the polymerization initiation system of the ink composition of the present invention has sufficient sensitivity even with a low output actinic radiation. 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 and gas / solid lasers are mainly used as actinic radiation sources, and mercury lamps and metal halide lamps are widely known as light sources used for curing UV photocurable ink jet recording inks. Yes. However, from the viewpoint of environmental protection, mercury-free is strongly desired, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as light sources for photo-curable ink jets.
Further, a light emitting diode (LED) and a laser diode (LD) can be used as the active radiation source. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. If even shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit actinic radiation centered between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. The actinic radiation source particularly preferred in the present invention is a UV-LED, particularly preferably a UV-LED having a peak wavelength at 350 to 420 nm.
Incidentally, it is preferable that maximum illumination intensity of the LED on a recording medium is 10 to 2,000 mW / cm ^2, more preferably 20 to 1,000 mW / cm ^2, particularly preferably 50 to 800 mW / cm ² .

The ink composition of the present invention is appropriately irradiated with such actinic radiation, preferably for 0.01 to 120 seconds, more preferably for 0.1 to 90 seconds.
Actinic radiation irradiation conditions and a basic irradiation method are disclosed in JP-A-60-132767. Specifically, the light source is provided on both sides of the head unit including the ink ejection device, and the head unit and the light source are scanned by a so-called shuttle method. Irradiation with actinic radiation takes a certain period of time (preferably 0.01 to 0.5 seconds, more preferably 0.01 to 0.3 seconds, still more preferably 0.01 to 0.15 seconds) after ink landing. Will be done. In this way, by controlling the time from ink landing to irradiation to an extremely short time, it is possible to prevent the ink that has landed on the recording medium from spreading before curing. Further, it is preferable that the porous recording medium can be exposed before the ink penetrates to a deep portion where the light source does not reach, so that the remaining unreacted monomer can be suppressed.
Further, curing may be completed by another light source that is not driven. International Publication No. 99/54415 pamphlet discloses a method using an optical fiber or a method of irradiating a recording unit with UV light by applying a collimated light source to a mirror surface provided on the side of the head unit, as an irradiation method. Such a curing method can also be applied to the ink jet recording method of the present invention.

By adopting the ink jet recording method as described above, the dot diameter of the landed ink 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 lowest brightness. By superimposing the inks in the order of low lightness, it becomes easier for the irradiation line to reach the lower ink, 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 actinic radiation.

  In the ink jet recording method of the present invention, the ink set of the present invention can be suitably used. The order of each colored ink composition to be ejected is not particularly limited, but it is preferably applied to a recording medium from a colored ink composition having low brightness, and four colors of yellow, cyan, magenta and black are used. In this case, it is preferable that the toner is applied on the recording medium in the order of yellow → cyan → magenta → black. In addition, when five colors including white are used, it is preferable to apply them on the recording medium in the order of white → yellow → cyan → magenta → black. Furthermore, the present invention is not limited to this, and the ink set of the present invention including at least eight colors of cyan, light cyan, magenta, light magenta, gray, black, white, and yellow can be preferably used.

  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, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. In addition, as the recording medium in the present invention, a non-absorbable recording medium can be preferably used.

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

The materials used in the present invention are as shown below.
・ IRGALITETE BLUE GLVO (Cyan Pigment, Ciba Specialty Chemicals)
・ CINQUASIA MAGENTA RT-335 D (Magenta pigment, manufactured by Ciba Specialty Chemicals)
・ NOVOPERM YELLOW H2G (yellow pigment, manufactured by Clariant)
SPECIAL BLACK 250 (black pigment, manufactured by Ciba Specialty Chemicals)
・ KRONOS2300 (white pigment, manufactured by KRONOS)
Exemplified compound M-1 (1-adamantyl acrylate)
Exemplified compound M-22
・ Fancrill 512A (corresponding to exemplary compound M-11, manufactured by Hitachi Chemical Co., Ltd.)
・ Fancryl 513A (corresponding to Exemplified Compound M-13, manufactured by Hitachi Chemical Co., Ltd.)
・ Fancrill 511A (equivalent to Exemplified Compound M-10, manufactured by Hitachi Chemical Co., Ltd.)
・ Fancryl 513M (equivalent to Exemplified Compound M-19, manufactured by Hitachi Chemical Co., Ltd.)
・ N-Vinylcaprolactam (NVC, manufactured by BASF)
・ KAYARAD DPCA-60 (DPCA, caprolactone-modified dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd.)
-Solsperse 32000 (Noveon dispersant)
Solsperse 36000 (Noveon dispersant)
DisperBYK-168 (polymer dispersant manufactured by BYK Chemie)
NK ester AMP-10G (PEA, phenoxyethyl acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ Rapi-Cure DVE-3 (triethylene glycol divinyl ether, manufactured by ISP Europe)
FIRSTCURE ST-1 (polymerization inhibitor, manufactured by Chem First)
・ Lucirin TPO (Photoinitiator manufactured by BASF)
・ Benzophenone (Photoinitiator, Wako Pure Chemical Industries, Ltd.)
・ Irgacure 184 (Photoinitiator, manufactured by Ciba Specialty Chemicals)
・ KF-353 (silicone surfactant, manufactured by Shin-Etsu Chemical Co., Ltd.)
-BYK-307 (surfactant, manufactured by BYK Chemie)
-FIRSTCURE ITX (sensitizer, manufactured by Chem First)

(Synthesis of Exemplified Compound M-1)
Exemplified compound M-1 (1-adamantyl acrylate) was obtained by a reaction between 1-adamantanol (Aldrich) and acryloyl chloride (Aldrich).

(Synthesis of Exemplified Compound M-22)
Exemplified compound M-22 was obtained by reaction of the following alcohol A with acrylic acid chloride.

(Preparation of cyan mill base A)
300 parts by weight of IRGALITETE BLUE GLVO, 650 parts by weight of NK ester AMP-10G, and 50 parts by weight of Solsperse 32000 were mixed with stirring to obtain a pigment ink. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 2 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of magenta mill base B)
300 parts by weight of CINQUASIA MAGENTA RT-335 D, 640 parts by weight of NK ester AMP-10G, and 60 parts by weight of Solsperse 32000 were mixed with stirring to obtain a pigment ink. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 7 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of yellow mill base C)
300 parts by weight of NOVOPERM YELLOW H2G, 640 parts by weight of NK ester AMP-10G, and 60 parts by weight of Solsperse 32000 were mixed with stirring to obtain a pigment ink. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 5 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of black mill base D)
300 parts by weight of SPECIAL BLACK 250, 650 parts by weight of NK ester AMP-10G, and 50 parts by weight of Solsperse 32000 were stirred and mixed to obtain a pigment ink. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 3 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of white mill base E)
650 parts by weight of KRONOS 2300, 280 parts by weight of NK ester AMP-10G, and 70 parts by weight of Solsperse 36000 were stirred and mixed to obtain a pigment ink. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 4 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

<Inkjet image recording method>
Next, recording on a recording medium was performed using an inkjet recording experimental apparatus having a piezoelectric inkjet nozzle. The ink supply system was composed of an original tank, supply piping, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head, and heat insulation and heating were performed from the ink supply tank to the inkjet head portion. Temperature sensors were provided near the ink supply tank and the nozzles of the ink jet head, respectively, and temperature control was performed so that the nozzle portions were always 45 ° C. ± 2 ° C. The piezo-type inkjet head was driven so that 8 to 30 pl multi-size dots could be ejected at a resolution of 720 × 720 dpi. After landing, UV light was condensed to an exposure surface illuminance of 1,630 mW / cm ² , and the exposure system, main scanning speed, and ejection frequency were adjusted so that irradiation started 0.1 seconds after ink landing on the recording medium. Further, the integrated light amount irradiated to the image was set to 1,500 mJ / cm ² . As an ultraviolet lamp, a HAN250NL high-cure mercury lamp (manufactured by GS Yuasa Corporation) was used. In the present invention, dpi represents the number of dots per 2.54 cm. As a recording medium, an ester film E5000 (film thickness 125 μm, manufactured by Toyobo Co., Ltd.) was used.

(Evaluation of surface tack-free properties)
In accordance with the ink jet recording method, an A6 size solid image having an average film thickness of 12 μm was drawn, and the degree of stickiness of the image was evaluated by palpation on the image surface after ultraviolet irradiation. The curing sensitivity was evaluated according to the following criteria.
3: No stickiness in the image.
2: The image is slightly sticky.
1: Uncured ink is not hard enough to transfer to hand.

(Evaluation of blocking resistance of cured film)
In accordance with the ink jet recording method, an A6 size solid image is drawn with an average film thickness of 12 μm, and an A6 size ester film E5000 (film thickness 125 μm, manufactured by Toyobo Co., Ltd.) is overlaid so that the entire cured film surface is covered. Further, 1 kg of A6 size ester film E5000 (thickness: 125 μm, manufactured by Toyobo Co., Ltd.) is placed as a weight, and left at 40 ° C. for 24 hours. After leaving, the A6 size ester film E5000 stacked on the cured film is peeled off, and the degree to which the cured film is transferred is evaluated.
The evaluation criteria are as follows.
4: There is no transfer to the overlaid PET film.
3: Transfer to the superimposed PET film is confirmed, but the area is 5% or less of the entire area of the cured film.
2: The transfer area to the overlapped PET film is 5% to 30% of the entire cured film area.
1: The transfer area to the overlapped PET film is 30% or more of the entire cured film area.

(Evaluation of water resistance of cured film)
According to the inkjet recording method, an A6 size solid image having an average film thickness of 12 μm was drawn. The cured film was rubbed 5 times with a cotton swab (made by the Consumers' Cooperative Association) to which water was sufficiently supplied, and the degree of peeling of the cured film was evaluated. The evaluation criteria are as follows.
3: The cured film does not peel at all.
2: The upper surface of the cured film is peeled off.
1: The cured film is peeled down to the bottom, and the support is exposed.

(Evaluation of solvent resistance of cured film)
According to the inkjet recording method, an A6 size solid image having an average film thickness of 12 μm was drawn. The cured film was rubbed 5 times with a cotton swab (manufactured by the Consumers' Cooperative Association) in which isopropyl alcohol was sufficiently supplied, and the degree of peeling of the cured film was evaluated. The evaluation criteria are as follows.
3: The cured film does not peel at all.
2: The upper surface of the cured film is peeled off.
1: The cured film is peeled down to the bottom, and the support is exposed.

(Adhesion evaluation)
According to the inkjet recording method, an A6 size solid image having an average film thickness of 12 μm was drawn. A cross cut test tape peeling test was performed using PI-1003 (pitch width 1 mm) manufactured by Tester Sangyo Co., Ltd. as a cross cutter and Scoch 610-1PK (manufactured by 3M Co.) as a cross cut tape.
The evaluation criteria are as follows.
3: The image is peeled only in an area of 1% or less in the portion where the tape is adhered.
2: The image having an area of 1% or more and less than 10% of the portion where the tape was adhered was peeled off.
1: The image of the area of 10% or more peeled off in the part where the tape was adhered.

(Viscosity measurement method)
The viscosity in this example was measured using a B-type viscometer: Brookfield LVDV-I (manufactured by Brookfield) at 25 ° C. and a rotor rotation speed of 20 rpm.

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability are shown in Table 1.

[Example 1]
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 20 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 57.5 parts ・ N-vinylcaprolactam 14.5 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ Benzophenone 3.2 part ・ Irgacure 184 2.44 part ・ KF-353 0.06 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

[Example 2]
The following components were stirred with a high-speed water-cooled stirrer to obtain a magenta UV inkjet ink. The viscosity was 23 mPa · s.
(Magenta ink composition)
・ Magenta mill base B 13.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 55.4 parts ・ N-vinylcaprolactam 10.0 parts ・ KAYARAD DPCA-60 1.4 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ Benzophenone 3.2 part ・ FIRSTCURE ITX 3.00 part ・ KF-353 0.06 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 3
The following components were stirred with a high-speed water-cooled stirrer to obtain a yellow UV inkjet ink. The viscosity was 22 mPa · s.
(Yellow color ink composition)
・ Yellow Mill Base C 13.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 58.4 parts ・ N-vinylcaprolactam 10.0 parts ・ KAYARAD DPCA-60 1.4 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ benzophenone 3.2 part ・ KF-353 0.06 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 4
The following components were stirred with a high-speed water-cooled stirrer to obtain a black UV inkjet ink. The viscosity was 19 mPa · s.
(Black ink composition)
・ Black mill base D 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 57.5 parts ・ N-vinylcaprolactam 14.5 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ Benzophenone 3.2 part ・ Irgacure 184 2.44 part ・ KF-353 0.06 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 5
The following components were stirred with a high-speed water-cooled stirrer to obtain a white UV inkjet ink. The viscosity was 24 mPa · s.
(White ink composition)
・ White Mill Base E 22.0 parts ・ Fancrill 512A 55.4 parts ・ N-vinylcaprolactam 12.0 parts ・ FIRSTCURE ST-1 0.05 parts ・ Lucirin TPO 8.5 parts ・ Irgacure 184 2.0 parts ・ BYK -307 0.05 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 6
The following components were stirred with a high-speed water-cooled stirrer to obtain a light cyan UV inkjet ink. The viscosity was 21 mPa · s.
(Light cyan ink composition)
・ Cyan Mill Base A 1.3 parts ・ DisperBYK-168 5.0 parts ・ Fancrill 512A 58.5 parts ・ N-vinylcaprolactam 15.2 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ benzophenone 3.2 part ・ Irgacure 184 2.44 part ・ KF-353 0.06 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 7
The following components were stirred with a high-speed water-cooled stirrer to obtain a light magenta UV inkjet ink. The viscosity was 24 mPa · s.
(Light magenta ink composition)
・ Magenta mill base B 2.4 parts ・ DisperBYK-168 5.0 parts ・ Fancrill 512A 58.4 parts ・ N-vinylcaprolactam 14.6 parts ・ KAYARAD DPCA-60 1.4 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ Benzophenone 3.2 part ・ FIRSTCURE ITX 3.00 part ・ KF-353 0.06 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 8
The following components were stirred with a high-speed water-cooled stirrer to obtain a light black UV inkjet ink. The viscosity was 20 mPa · s.
(Light black ink composition)
・ Black Mill Base D 1.0 part ・ DisperBYK-168 5.0 parts ・ Fancrill 512A 56.5 parts ・ N-vinylcaprolactam 17.5 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ benzophenone 3.2 part ・ Irgacure 184 2.44 part ・ KF-353 0.06 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 9
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 17 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 511A 57.5 parts ・ N-vinylcaprolactam 14.5 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ benzophenone 3.2 part ・ Irgacure 184 2.44 part ・ KF-353 0.06 part

Example 10
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 17 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrile 513A 57.5 parts ・ N-vinylcaprolactam 14.5 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ benzophenone 3.2 part ・ Irgacure 184 2.44 part ・ KF-353 0.06 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability are shown in Table 1.

Example 11
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 18 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancryl 513M 30.0 parts ・ Fankrill 512A 27.5 parts ・ N-vinylcaprolactam 14.5 parts ・ KAYARAD DPCA-60 2.0 parts・ Rapi-Cure DVE-3 3.0 parts ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 parts ・ Benzophenone 3.2 parts ・ Irgacure 184 2.44 parts ・ KF-353 0.06 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 12
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 26 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Exemplary Compound M-1 57.5 parts ・ N-vinylcaprolactam 14.5 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE- 3 3.0 parts ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 parts ・ Benzophenone 3.2 parts ・ Irgacure 184 2.44 parts ・ KF-353 0.06 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 13
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 26 mPa · s.
(Cyan ink composition)
-Cyan Mill Base A 6.0 parts-DisperBYK-168 2.0 parts-Exemplified Compound M-22 57.5 parts-N-Vinylcaprolactam 14.5 parts-KAYARAD DPCA-60 2.0 parts-Rapi-Cure DVE- 3 3.0 parts ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 parts ・ Benzophenone 3.2 parts ・ Irgacure 184 2.44 parts ・ KF-353 0.06 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 14
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 24 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 65.5 parts ・ N-vinylcaprolactam 11.5 parts ・ FIRSTCURE ST-1 0.3 parts ・ Lucirin TPO 9.0 parts ・Benzophenone 3.2 parts Irgacure 184 2.44 parts KF-353 0.06 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 15
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 27 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ Fancrill 512A 71.5 parts ・ N-vinylcaprolactam 10.0 parts ・ FIRSTCURE ST-1 0.24 parts ・ Lucirin TPO 8.0 parts ・ Benzophenone 2.2 parts ・ Irgacure 184 2.0 parts ・ KF-353 0.06 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 16
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 26 mPa · s.
(Cyan ink composition)
・ Cyan mill base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 56.0 parts ・ NK ester AMP-10G 15.0 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3.0 parts ・ FIRSTCURE ST-1 0.3 parts ・ Lucirin TPO 9.0 parts ・ Benzophenone 3.2 parts ・ Irgacure 184 2.44 parts ・ KF-353 0.06 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results are shown in Table 1.

Example 17
Using the eight ink compositions prepared in Examples 1 to 8, the following full-color image recording was performed. The evaluation results are shown in Table 1.

<Inkjet image recording method (full color)>
Next, recording on a full-color recording medium was performed using an inkjet recording experimental apparatus having a piezoelectric inkjet nozzle. The ink jet recording apparatus has a total of eight ink supply systems, and the ink supply systems are independent for each ink supply meter, and each of the original tank, supply pipe, ink supply tank immediately before the ink jet head, filter, and piezo type It consists of an inkjet head. Each ink tank is filled with cyan, magenta, yellow, black, white, light cyan, light magenta, and light black ink prepared in Examples 1 to 8, respectively, and heat insulation and heating from the ink supply tank to the inkjet head portion are performed. went. Temperature sensors were provided near the ink supply tank and the nozzles of the ink jet head, respectively, and temperature control was performed so that the nozzle portions were always 45 ° C. ± 2 ° C. The eight piezo-type inkjet heads were arranged in parallel, and were driven simultaneously so that 8 to 30 pl multi-size dots could be ejected with a resolution of 720 × 720 dpi. After landing, UV light is condensed to an exposure surface illuminance of 1,630 mW / cm ² and the exposure system, main scanning speed, and emission are set so that irradiation starts 0.1 seconds to 0.3 seconds after ink has landed on the recording medium. The frequency was adjusted. Further, the integrated light amount irradiated to the image was set to 1,500 mJ / cm ² . As an ultraviolet lamp, a HAN250NL high-cure mercury lamp (manufactured by GS Yuasa Corporation) was used. In the present invention, dpi represents the number of dots per 2.54 cm. As a recording medium, an ester film E5000 (film thickness 125 μm, manufactured by Toyobo Co., Ltd.) was used.
A composite black solid image having a film thickness of 12 μm was prepared using all of the filled eight ink colors.

Example 18
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 20 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 57.5 parts ・ N-vinylcaprolactam 14.5 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ Benzophenone 3.2 part ・ Irgacure 184 2.44 part ・ KF-353 0.06 part

(Evaluation of ink)
The UV light after landing is condensed to an exposure surface illuminance of 350 mW / cm ² , and the integrated light amount irradiated to the image is 1,500 mJ / cm ^{2. The} lamp is a UV-LED lamp: NCCU033 (manufactured by Nichia Corporation) Inkjet recording was carried out by the same method as that for inkjet recording except that was used. The evaluation results of curability are shown in Table 1.

Example 19
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 20 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 57.5 parts ・ N-vinylcaprolactam 14.5 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3 .0 part ・ FIRSTCURE ST-1 0.3 part ・ Lucirin TPO 9.0 part ・ Benzophenone 3.2 part ・ Irgacure 184 2.44 part ・ KF-353 0.06 part

(Evaluation of ink)
The UV light after landing is condensed to an exposure surface illuminance of 450 mW / cm ² , the integrated light quantity irradiated to the image is set to 8,000 mJ / cm ² , and the lamp is an ultra-high pressure generally used for projector applications etc. Mercury lamp: Inkjet recording was performed in the same manner as the above inkjet recording except that SHP270W (Phoenix Electric Co., Ltd.) was used. There was no missing dot in the obtained image, and a bright image with a thickness of 12 μm could be drawn. Table 1 shows the evaluation results of curing sensitivity, cured film flexibility, and adhesion.

[Comparative Example 1]
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 22 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ Fancrill 512A 43.0 parts ・ NK Ester AMP-10G 28.0 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3.0 parts ・ FIRSTCURE ST-1 0.3 parts ・ Lucirin TPO 9.0 parts ・ Benzophenone 3.2 parts ・ Irgacure 184 2.44 parts ・ KF-353 0.06 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability are shown in Table 1.

[Comparative Example 2]
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink. The viscosity was 15 mPa · s.
(Cyan ink composition)
・ Cyan Mill Base A 6.0 parts ・ DisperBYK-168 2.0 parts ・ NK Ester AMP-10G 71.0 parts ・ KAYARAD DPCA-60 2.0 parts ・ Rapi-Cure DVE-3 3.0 parts ・ FIRSTCURE ST- 1 0.3 parts ・ Lucirin TPO 9.0 parts ・ Benzophenone 3.2 parts ・ Irgacure 184 2.44 parts ・ KF-353 0.06 parts

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability are shown in Table 1.

Claims (8)

An ink composition comprising a total of 50% by weight or more of monomers represented by formula (I) and / or formula (II) in an ink composition.

(In Formula (I) and Formula (II), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, R ² and R ³ Each independently represents a substituent, k represents an integer of 1 to 6, q and r each independently represents an integer of 0 to 5, n represents a cyclic hydrocarbon structure, and carbonized as the cyclic hydrocarbon structure In addition to a hydrogen bond, a carbonyl bond (—C (O) —) and / or an ester bond (—C (O) O—) may be included, k existing R ¹ , k existing X ¹ , q R ² present and R ³ present may be the same or different, and one carbon atom in the adamantane skeleton in the formula (I) is bonded to a carbonyl bond (—C (O )-) And / or an ester bond (—C (O) O—) One carbon atom in the rubornene skeleton may be substituted with an ether bond (—O—) and / or an ester bond (—C (O) O—).   The ink composition according to claim 1, wherein at least one of the monomers represented by the formula (I) or the formula (II) is a monofunctional acrylate. The ink composition according to claim 1, wherein the monomer represented by the formula (II) is a monomer represented by the formula (III), the formula (IV), or the formula (V).

(In Formula (III), Formula (IV) and Formula (V), R ¹ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, X ¹ represents a divalent linking group, R ⁴ , R ⁵ and R ⁶ each independently represent a substituent, k represents an integer of 1 to 6, s, t and u each independently represents an integer of 0 to 5, and s are present. R ⁴ , R ⁵ present in t, and R ⁶ present in u may be the same or different.   The ink composition according to claim 1, wherein the ink composition is for inkjet recording.   5. The ink composition according to claim 1, wherein the ink composition is selected from the group consisting of cyan, magenta, yellow, black, white, light magenta, light cyan, and light black. Ink set containing two or more. (A ¹⁾ onto a recording medium, a step of discharging the ink composition according to any one of claims 1 to 4 and,
(B ¹ ) An inkjet recording method comprising a step of irradiating the discharged ink composition with actinic radiation to cure the ink composition. 7. The active radiation is irradiated by a light emitting diode having an emission peak wavelength in a range of 350 to 420 nm and a maximum illuminance on a recording medium surface of 10 to 2,000 mW / cm ^2. Inkjet recording method.   Printed matter recorded by the ink jet recording method according to claim 6 or 7.