JP2009067956A - Ink composition for inkjet, method for inkjet recording and print - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition for inkjets having little viscosity variation with time and excellent stability with time, curability, flexibility and adhesiveness, to provide a method for inkjet recording and to provide a print. <P>SOLUTION: The ink composition for the inkjets is characterized by comprising (A) N-vinyllactams, (B) a pigment, (C) a polymer represented by formula (1) äwherein, R<SP>1</SP>represents a (m+n)-valent organic linking group; R<SP>2</SP>represents a single bond or a divalent organic linking group; A<SP>1</SP>represents a monovalent organic group having a group selected from the group consisting of an acidic group, a group having a basic nitrogen atom, a urea group, a urethane group a group having a coordinating oxygen atom, a ≥4C hydrocarbon group, an alkoxysilyl group, an epoxy group, an isocyanate group and a hydroxy group; and P<SP>1</SP>represents a polymer skeleton} and (D) a radical polymerization initiator. The method for inkjet recording and the print are provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  As an image recording method for forming an image on a recording medium such as paper based on an image data signal, an electrophotographic method, a sublimation / melting thermal transfer method, an ink jet method, and the like are known. Among these, the ink jet method can be implemented with an inexpensive apparatus, and the ink is efficiently used because it forms an image directly on a recording medium by ejecting ink only to a required image portion. The running cost is low, the noise is low, and the image recording method is excellent. According to the inkjet method, printing is possible not only on plain paper but also on non-water-absorbing recording media such as plastic sheets and metal plates, but speeding up and high image quality are important issues when printing. In addition, the time required for drying and curing the droplets after printing has a property of greatly affecting the sharpness of the image.

As one of the ink jet methods, there is a recording method using a curable ink composition for ink jet recording which can be cured by irradiation with actinic radiation. According to this method, a sharp image can be formed by irradiating with radiation immediately after printing and curing the ink droplets.
The curable ink composition is required to have high pigment dispersibility and stability over time in order to form a high-definition image having excellent color developability. Generally, in order to give a clear color tone and high coloring power to an ink composition, it is essential to make the pigment finer. In particular, in an ink composition for ink jet recording, the ejected ink droplets have a sharpness of the image. Therefore, it is essential to use particles that are smaller in volume than the thickness of the ink cured film formed by the ink composition. As described above, if the pigment is made finer to obtain a high coloring power, it becomes difficult to disperse the pigment, and a pigment aggregate is formed. When the pigment dispersant is added, the viscosity of the ink composition is increased. The problem of rising. The occurrence of pigment aggregates and the increase in the viscosity of the ink composition both adversely affect the ink ejection properties and cause a significant decrease in the performance of the ink composition. Further, the ink composition used in the ink jet method is housed in a cartridge, heated during ejection, and cooled during non-ejection and storage, and thus undergoes repeated heating-cooling temperature changes. There is a problem in that the dispersibility is adversely affected, the dispersibility of the pigment is lowered with time, and thickening and aggregation are likely to occur.

For this reason, there is a need for an ink composition that has sufficient fluidity, stably disperses the finely divided pigment, and is excellent in the temporal dispersion stability of the pigment dispersion. Various proposals have been made on dispersants for obtaining pigment dispersions.
For example, an ink composition using a pigment derivative as a dispersant (see Patent Documents 1 and 2), a specific group such as phthalocyanine or quinacridone to improve the affinity with the pigment, a basic group as a dispersant. An ink composition using a polymer having a polymer (see Patent Document 3), a dispersant such as poly (ethyleneimine) -poly (12-hydroxystearic acid) graft polymer, and a specific monomer that dissolves the dispersant; An ink composition that does not use an organic solvent (see Patent Document 4) has been proposed.
However, in the case of these ink compositions, although the pigment dispersion stability is improved by the function of the dispersant as compared with the prior art, the fineness of the pigment used is insufficient, and further fine pigment particles There is room for improvement in the effect of improving the dispersibility, and there is a problem that the dispersion stability after a long period of time or after repeated temperature changes is not sufficient.

  In addition, there is a demand for achieving a desired color gamut, and for this purpose, radiation curable inkjet inks using special color pigments such as Pigment Orange and Pigment Green are disclosed (for example, see Patent Document 5).

JP 2003-119414 A JP 2004-18656 A JP 2003-321628 A JP 2004-131589 A Special table 2003-53223 gazette

  An object of the present invention is an ink-jet ink composition having little viscosity variation with time and excellent in stability over time, curability, flexibility and adhesion, and an ink-jet recording method and a printed matter using the ink-jet ink composition Is to provide.

The above object has been achieved by the means described in <1>, <7> and <9> below. It is shown below with <2>-<6> and <8> which are preferable embodiments.
<1> It contains (A) N-vinyl lactams, (B) pigment, (C) a polymer compound represented by the following formula (1), and (D) a radical polymerization initiator. An ink-jet ink composition;

（式中、Ｒ¹は、（ｍ＋ｎ）価の有機連結基を表し、Ｒ²は単結合又は２価の有機連結基を表す。Ａ¹は、酸性基、塩基性窒素原子を有する基、ウレア基、ウレタン基、配位性酸素原子を有する基、炭素数４以上の炭化水素基、アルコキシシリル基、エポキシ基、イソシアネート基、及び、水酸基よりなる群から選択される基を有する１価の有機基を表し、ｎ個のＡ¹は同一であっても、異なっていてもよい。ｍは１〜８を表し、ｎは２〜９を表し、ｍ＋ｎは３〜１０を満たす。Ｐ¹は高分子骨格を表す。）
＜２＞ 前記高分子化合物が下記式（２）で表される上記＜１＞記載のインクジェット用インク組成物、

(In the formula, R ¹ represents an (m + n) -valent organic linking group, R ² represents a single bond or a divalent organic linking group. A ¹ represents an acidic group, a group having a basic nitrogen atom, urea. Monovalent organic having a group selected from the group consisting of a group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, an epoxy group, an isocyanate group, and a hydroxyl group It represents a radical, n pieces of a ¹ may be the same, may be different .m represents 1 to 8, n represents 2 to 9, m + n is .P ¹ satisfying 3-10 high Represents molecular skeleton.)
<2> The inkjet ink composition according to <1>, wherein the polymer compound is represented by the following formula (2):

（式中、Ｒ³は、（ｍ＋ｎ）価の有機連結基を表し、Ｒ⁴及びＲ⁵は、各々独立に単結合あるいは２価の有機連結基を表す。Ａ²は、酸性基、塩基性窒素原子を有する基、ウレア基、ウレタン基、配位性酸素原子を有する基、炭素数４以上の炭化水素基、アルコキシシリル基、エポキシ基、イソシアネート基、及び、水酸基よりなる群から選択される基を有する１価の有機基を表し、ｎ個のＡ²は同一であっても、異なっていてもよい。ｍは１〜８を表し、ｎは２〜９を表し、ｍ＋ｎは３〜１０を満たす。Ｐ²は高分子骨格を表す。）
＜３＞ （Ｅ）式（I）又は式（II）で表されるエチレン性不飽和モノマーを含有する上記＜１＞又は＜２＞に記載のインクジェット用インク組成物、

(Wherein R ³ represents an (m + n) -valent organic linking group, and R ⁴ and R ⁵ each independently represents a single bond or a divalent organic linking group. A ² represents an acidic group or a basic group. Selected from the group consisting of a group having a nitrogen atom, a urea group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, an epoxy group, an isocyanate group, and a hydroxyl group Represents a monovalent organic group having a group, and n A ² may be the same or different, m represents 1 to 8, n represents 2 to 9, and m + n represents 3 to 10 P ² represents a polymer skeleton.)
<3> (E) The inkjet ink composition according to <1> or <2> above, which contains an ethylenically unsaturated monomer represented by formula (I) 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。）
＜４＞ （Ｆ）フェノキシエチル（メタ）アクリレートを含有する上記＜１＞〜＜３＞のいずれか１つに記載のインクジェット用インク組成物、
＜５＞ 前記顔料が、イエロー顔料、マゼンタ顔料、シアン顔料、緑色顔料、オレンジ顔料、黒色顔料及び白色顔料よりなる群から選ばれた少なくとも１種である上記＜１＞〜＜４＞のいずれか１つに記載のインクジェット用インク組成物、
＜６＞ 前記顔料が、イエロー顔料、マゼンタ顔料、シアン顔料、黒色顔料及び白色顔料よりなる群から選ばれた少なくとも１種である上記＜１＞〜＜５＞のいずれか１つに記載のインクジェット用インク組成物、
＜７＞ （ａ¹）被記録媒体上に、上記＜１＞〜＜６＞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、
＜８＞ 前記活性放射線が、発光ピーク波長が３５０〜４２０ｎｍの範囲にあり、且つ、被記録媒体表面での最高照度が１０〜２，０００ｍＷ／ｃｍ²となる紫外線を発生する発光ダイオードにより照射される紫外線である上記＜７＞に記載のインクジェット記録方法、
＜９＞ 上記＜７＞又は＜８＞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 (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—).
<4> (F) The inkjet ink composition according to any one of the above <1> to <3>, which contains phenoxyethyl (meth) acrylate,
<5> Any one of <1> to <4>, wherein the pigment is at least one selected from the group consisting of a yellow pigment, a magenta pigment, a cyan pigment, a green pigment, an orange pigment, a black pigment, and a white pigment. Ink-jet ink composition according to one,
<6> The inkjet according to any one of <1> to <5>, wherein the pigment is at least one selected from the group consisting of a yellow pigment, a magenta pigment, a cyan pigment, a black pigment, and a white pigment. Ink composition,
<7> (a ¹ ) A step of discharging the ink composition according to any one of the above <1> to <6> on a recording medium, and (b ¹ ) the discharged ink composition Irradiating actinic radiation to cure the ink composition, an inkjet recording method comprising:
<8> The actinic radiation is irradiated by a light emitting diode that generates ultraviolet rays 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. The inkjet recording method according to <7>, wherein
<9> A printed matter recorded by the inkjet recording method according to <7> or <8>.

  According to the present invention, an ink-jet ink composition having little viscosity variation over time and excellent in stability over time, curability, flexibility and adhesion, and an ink-jet recording method and a printed matter using the ink-jet ink composition are provided. Could be provided.

(Ink composition)
The ink-jet ink composition of the present invention (in the present invention, the “ink-jet ink composition” is also simply referred to as “ink composition” or “ink”) is (A) N-vinyl lactam, (B) pigment. (C) a polymer compound represented by the following formula (1) (hereinafter also simply referred to as “polymer of formula (1)” or “polymer compound”), and (D) a radical polymerization initiator. It is characterized by containing.
The inkjet ink composition of the present invention can be suitably used as an ink composition used for inkjet recording.

（式中、Ｒ¹は、（ｍ＋ｎ）価の有機連結基を表し、Ｒ²は単結合又は２価の有機連結基を表す。Ａ¹は、酸性基、塩基性窒素原子を有する基、ウレア基、ウレタン基、配位性酸素原子を有する基、炭素数４以上の炭化水素基、アルコキシシリル基、エポキシ基、イソシアネート基、及び、水酸基よりなる群から選択される基を有する１価の有機基を表し、ｎ個のＡ¹は同一であっても、異なっていてもよい。ｍは１〜８を表し、ｎは２〜９を表し、ｍ＋ｎは３〜１０を満たす。Ｐ¹は高分子骨格を表す。）
また、本発明のインクジェット用インク組成物は、必要に応じて、適宜、その他の成分を含有していてもよい。

(In the formula, R ¹ represents an (m + n) -valent organic linking group, R ² represents a single bond or a divalent organic linking group. A ¹ represents an acidic group, a group having a basic nitrogen atom, urea. Monovalent organic having a group selected from the group consisting of a group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, an epoxy group, an isocyanate group, and a hydroxyl group It represents a radical, n pieces of a ¹ may be the same, may be different .m represents 1 to 8, n represents 2 to 9, m + n is .P ¹ satisfying 3-10 high Represents molecular skeleton.)
Moreover, the ink composition for inkjet of this invention may contain the other component suitably as needed.

The ink composition of the present invention can be cured when irradiated with active energy rays.
The active energy ray is not particularly limited and may be appropriately selected depending on the purpose as long as it can impart energy capable of generating a starting species of a curing reaction in the ink composition by irradiation. Examples thereof include α rays, γ rays, X rays, ultraviolet rays, visible rays, and electron beams. In the present invention, among these, ultraviolet rays and electron beams are preferable, and ultraviolet rays are particularly preferable from the viewpoint of curing sensitivity and device availability.

(A) N-vinyl lactams The ink composition of the present invention contains N-vinyl lactams (hereinafter also referred to as “component (A)”).
Preferable examples of N-vinyl lactams that can be used in the present invention include compounds represented by the following formula (A-1).

In the formula (A-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 5% by weight or more of N-vinyl lactam, more preferably 5% by weight or more and 40% by weight or less, still more preferably 10% by weight or more and 40% by weight. % 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.

(B) Pigment The (B) pigment (hereinafter also referred to simply as “(B) component” or “pigment”) functions as a colorant for the ink composition. As a result of the fine pigment of the present invention being dispersed uniformly and stably in the ink composition by the function of the polymer dispersant, the ink composition of the present invention has excellent color development, sharpness and excellent weather resistance. Can be formed.
The pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include known organic pigments and inorganic pigments. Resin particles dyed with dyes, commercially available pigment dispersions, The surface-treated pigment (for example, a pigment dispersed in an insoluble resin or the like using a pigment as a dispersion medium, or a pigment grafted with a resin on the pigment surface) can also be used. Examples of the pigment include, for example, “Spirit Dictionary of Pigments” (2000), edited by Seijiro Ito. Herbst, K.M. Examples include those described in Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A.

  Examples of the organic pigment and inorganic pigment include a yellow pigment, a magenta pigment, a cyan pigment, a green pigment, an orange pigment, a black pigment, and a white pigment.

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

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

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

The green pigment is a pigment exhibiting a green color. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).
The orange pigment is a pigment exhibiting an orange color. I. Pigment Orange 66 (Isoindoline Orange) and the like, C.I. I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

The black pigment is a black pigment, and examples thereof include carbon black, titanium black, and aniline black.
Examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), Examples thereof include strontium titanate (SrTiO ₃ , so-called titanium strontium white). Here, the titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable. It is preferably used because of its excellent durability against alkalis and other environments. In addition to the titanium oxide, another white pigment (may be other than the white pigment described above) may be used in combination.

  Among these, the ink composition of the present invention preferably contains at least one pigment selected from the group consisting of a yellow pigment, a magenta pigment, a cyan pigment, a black pigment, and a white pigment, More preferably, it contains at least one pigment selected from the group consisting of magenta pigments and cyan pigments.

For the dispersion of the pigment, for example, a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, etc. Can be preferably used.
In the present invention, it is particularly preferable to add the polymer compound when dispersing the pigment.
In addition, when dispersing the pigment, a synergist according to various pigments may be added as a dispersion aid if necessary. The content of the dispersion aid in the ink composition is preferably 1 to 50 parts by weight with respect to 100 parts by weight of the pigment.

  The dispersion medium used when the pigment is dispersed in the ink composition is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the polymerizable compound having a low molecular weight may be selected from the dispersion medium. Or a solvent may be used as the dispersion medium. However, the ink composition of the present invention is a radiation curable ink, and is preferably solvent-free without containing the solvent in order to cure the ink after it is applied to the recording medium. This is because if the solvent remains in the cured ink image, the solvent resistance is deteriorated or a VOC (Volatile Organic Compound) problem of the remaining solvent occurs. For this reason, it is preferable to use the polymerizable compound as the dispersion medium, and to select a polymerizable compound having the lowest viscosity among them in terms of dispersion suitability and handling property of the ink composition.

There is no restriction | limiting in particular as an average particle diameter of the said pigment, Although it can select suitably according to the objective, Since it is excellent in coloring property, so that it is fine, about 0.01-0.4 micrometer is preferable, and 0.02- 0.2 μm is more preferable. The maximum particle size of the pigment is preferably 3 μm or less, more preferably 1 μm or less. The pigment particle size can be adjusted by selecting the pigment, dispersant, dispersion medium, dispersion conditions, filtration conditions, etc., and controlling the pigment particle size prevents clogging of the head nozzle. In addition, the storage stability, transparency and curing sensitivity of the ink composition can be maintained. In the present invention, since the polymer dispersant excellent in dispersibility and stability is included, even when the pigment of particles is used, a uniform and stable ink composition can be obtained.
The particle diameter of the pigment in the ink composition can be measured by a known measurement method. Specifically, it can be measured by a centrifugal sedimentation light transmission method, an X-ray transmission method, a laser diffraction / scattering method, and a dynamic light scattering method.
The content of the pigment in the ink composition is preferably 1 to 20% by weight, more preferably 1.5 to 10% by weight in terms of solid content.

(C) Polymer Compound Represented by Formula (1) The inkjet ink composition of the present invention contains a polymer compound represented by formula (1) (also referred to as “component (C)”).
In the present invention, the component (C) functions or functions as a pigment dispersant, has a high affinity with the component (B), has a good adsorptivity to the component (B), and has a specific repeating structural unit. Therefore, the ink composition of the present invention containing the component (C) is excellent in dispersion stability due to the steric repulsion effect of the polymer chain.

  The polymer compound represented by the following formula (1) is an acid group, a group having a basic nitrogen atom, a urea group, a urethane group, a group having a coordinating oxygen atom, or a group having 4 or more carbon atoms at the end of the polymer. Since it has a plurality of functional groups selected from the group consisting of hydrocarbon groups, alkoxysilyl groups, epoxy groups, isocyanate groups, and hydroxyl groups, it has excellent adsorptivity to solid surfaces, excellent micelle formation ability, and surface activity. It has various features such as having. For example, it can be suitably used as a pigment dispersant.

In the formula (1), A ¹ is an acidic group, a group having a basic nitrogen atom, a urea group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, It represents a monovalent organic group having a group selected from the group consisting of an epoxy group, an isocyanate group, and a hydroxyl group. The n A ^{1 s} may be the same or different.
Specifically, A ¹ is not particularly limited, and examples of the “monovalent organic group having an acidic group” include a carboxy group, a sulfonic acid group (—SO ₃ H), and a monosulfate ester residue. And monovalent organic groups having a group, a phosphate group, a monophosphate ester residue, a boric acid group, and the like. Among these, a carboxyl group, a sulfonic acid group, a monosulfate ester residue, a phosphate group, and a monophosphate ester residue are more preferable, and a carboxyl group, a sulfonate group, and a phosphate group are more preferable.

Examples of the “monovalent organic group having a group having a basic nitrogen atom” include, for example, a monovalent organic group having an amino group (—NH ₂ ), a substituted amino group (—NHR ⁸ , —NR ⁹ R). ¹⁰ ) having a monovalent organic group (wherein R ⁸ , R ⁹ , and R ¹⁰ are each independently an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 or more carbon atoms, or 7 or more carbon atoms). An aralkyl group.), A monovalent organic group having a guanidyl group represented by the following formula (a1), a monovalent organic group having an amidinyl group represented by the following formula (a2), and the like.

In formula (a1), R ¹¹ and R ¹² each independently represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 or more carbon atoms, or an aralkyl group having 7 or more carbon atoms.
In formula (a2), R ¹³ and R ¹⁴ each independently represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 or more carbon atoms, or an aralkyl group having 7 or more carbon atoms.

Among these, an amino group (—NH ₂ ), a substituted amino group (—NHR ⁸ , —NR ⁹ R ¹⁰ , where R ⁸ , R ⁹ , and R ¹⁰ are each independently a group having 1 to 10 carbon atoms. An alkyl group, a phenyl group, a benzyl group), a guanidyl group represented by the formula (a1) [in the formula (a1), R ¹¹ and R ¹² are each independently an alkyl group having 1 to 10 carbon atoms; Represents a phenyl group or a benzyl group. Amidinyl group represented by the formula (a2) [in the formula (a2), R ¹³ and R ¹⁴ each independently represents an alkyl group having 1 to 10 carbon atoms, a phenyl group, or a benzyl group. And the like, and an amino group (—NH ₂ ), a substituted amino group (—NHR ⁸ , —NR ⁹ R ¹⁰ , wherein R ⁸ , R ⁹ , and R ¹⁰ each independently has 1 to 5 carbon atoms. And a guanidyl group represented by the formula (a1) [in the formula (a1), R ¹¹ and R ¹² are each independently an alkyl having 1 to 5 carbon atoms. Represents a group, a phenyl group or a benzyl group. ] An amidinyl group represented by the formula (a2) [in the formula (a2), R ¹³ and R ¹⁴ each independently represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a benzyl group. ] Is particularly preferable.

As the “monovalent organic group having a urea group”, for example, —NR ¹⁵ CONR ¹⁶ R ¹⁷ (wherein R ¹⁵ , R ¹⁶ , and R ¹⁷ are each independently a hydrogen atom or a carbon number of 1 -20 alkyl groups, aryl groups having 6 or more carbon atoms, or aralkyl groups having 7 or more carbon atoms are preferred. Among these, —NR ¹⁵ CONHR ¹⁷ (wherein R ¹⁵ and R ¹⁷ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 or more carbon atoms, or 7 or more carbon atoms). -NHCONHR ¹⁷ (wherein R ¹⁷ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 or more carbon atoms, or an aralkyl group having 7 or more carbon atoms). .) Is more preferred.

Examples of the “monovalent organic group having a urethane group” include —NHCOOR ¹⁸ , —NR ¹⁹ COOR ²⁰ , —OCONHR ²¹ , —OCONR ²² R ²³ (where R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² and R ²³ each independently represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 or more carbon atoms, or an aralkyl group having 7 or more carbon atoms. Among these, —NHCOOR ¹⁸ , —OCONHR ²¹ (wherein R ¹⁸ and R ²¹ are each independently an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 or more carbon atoms, or an aralkyl having 7 or more carbon atoms). -NHCOOR ¹⁸ , -OCONHR ²¹ (wherein R ¹⁸ and R ²¹ are each independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 or more carbon atoms, or a carbon number). And more preferably 7 or more aralkyl groups).

Examples of the “group having a coordinating oxygen atom” include an acetylacetonato group and a group having a crown ether structure.
Preferred examples of the “hydrocarbon group having 4 or more carbon atoms” include an alkyl group having 4 or more carbon atoms, an aryl group having 6 or more carbon atoms, and an aralkyl group having 7 or more carbon atoms. Among these, a C4-C20 alkyl group, a C6-C20 aryl group, a C7-C20 aralkyl group, etc. are preferable, and a C4-C15 alkyl group (for example, an octyl group, a dodecyl group, etc.). An aryl group having 6 to 15 carbon atoms (for example, a phenyl group or a naphthyl group), an aralkyl group having 7 to 15 carbon atoms (for example, a benzyl group) or the like is more preferable.

Examples of the “alkoxysilyl group” include a trimethoxysilyl group and a triethoxysilyl group.
Examples of the “epoxy group” include a group having a glycidyl group.
Examples of the “isocyanate group” include a 3-isocyanatopropyl group.
Examples of the “group having a hydroxyl group” include a 3-hydroxypropyl group.

Among the above, A ¹ is preferably a monovalent organic group having a group selected from an acidic group, a group having a basic nitrogen atom, a urea group, and a hydrocarbon group having 4 or more carbon atoms. .

The A ¹ is preferably a monovalent organic group represented by the following formula (4).

In the formula (4), B ¹ is an acidic group, a group having a basic nitrogen atom, a urea group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, R ²⁴ represents a group selected from the group consisting of an epoxy group, an isocyanate group, and a hydroxyl group, and R ²⁴ represents a single bond or an (a + 1) -valent organic linking group. a represents an integer of 1 to 10, preferably 1 to 7, more preferably 1 to 5, and particularly preferably 1 to 3. The a B ¹ may be the same or different.

B ¹ has the same meaning as A ¹ in formula (4), and the preferred embodiment is also the same.
R ²⁴ represents a single bond or an (a + 1) -valent organic linking group, and a represents 1 to 10. (A + 1) valent organic linking group includes 1 to 100 carbon atoms, 0 to 10 nitrogen atoms, 0 to 50 oxygen atoms, 1 to 200 hydrogen atoms, And a group consisting of 0 to 20 sulfur atoms, which may be unsubstituted or further substituted.

  Specific examples of the (a + 1) -valent organic linking group include the following structural units or groups configured by combining the structural units. The substitution position of the following naphthalene ring or anthracene ring may be any position.

  Among the above, when the (a + 1) -valent organic linking group has a substituent, examples of the substituent include an alkyl group having 1 to 20 carbon atoms such as a methyl group and an ethyl group, a phenyl group, a naphthyl group, and the like. Such as an aryloxy group having 6 to 16 carbon atoms, a hydroxyl group, an amino group, a carboxyl group, a sulfonamide group, an N-sulfonylamide group, an acetoxy group and the like, an acyloxy group having 1 to 6 carbon atoms, a methoxy group, an ethoxy group, etc. Alkoxy groups having 1 to 6 carbon atoms, halogen atoms such as chlorine and bromine, alkoxycarbonyl groups having 2 to 7 carbon atoms such as methoxycarbonyl groups, ethoxycarbonyl groups, and cyclohexyloxycarbonyl groups, cyano groups, and t-butyl carbonate And carbonic acid ester groups.

In the formula (1), R ¹ represents an (m + n) -valent organic linking group. m + n satisfies 3-10.
Examples of the (m + n) -valent organic linking group represented by R ¹ include 1 to 100 carbon atoms, 0 to 10 nitrogen atoms, 0 to 50 oxygen atoms, 1 to Groups consisting of up to 200 hydrogen atoms and 0 to 20 sulfur atoms are included, which may be unsubstituted or further substituted.

  Specific examples of the (m + n) -valent organic linking group include the following structural units or groups formed by combining the structural units (which may form a ring structure). .

  Examples of the (m + n) -valent organic linking group include groups composed of 1 to 60 carbon atoms, 10 or less nitrogen atoms, 40 or less oxygen atoms, 1 to 120 hydrogen atoms, and 10 or less sulfur atoms. Preferably, a group composed of 1 to 50 carbon atoms, 10 or less nitrogen atoms, 30 or less oxygen atoms, 1 to 100 hydrogen atoms, and 7 or less sulfur atoms is more preferable, and 1 to 40 carbon atoms, A group composed of 8 or less nitrogen atoms, 20 or less oxygen atoms, 1 to 80 hydrogen atoms, and 5 or less sulfur atoms is particularly preferred.

  Among the above, when the polyvalent organic linking group has a substituent, examples of the substituent include carbon such as an alkyl group having 1 to 20 carbon atoms such as a methyl group and an ethyl group, a phenyl group, and a naphthyl group. Carbon number such as acyloxy group having 1 to 6 carbon atoms such as aryl group, hydroxyl group, amino group, carboxyl group, sulfonamido group, N-sulfonylamido group, acetoxy group, etc., methoxy group, ethoxy group, etc. Alkoxy groups having 1 to 6 carbon atoms, halogen atoms such as chlorine and bromine, alkoxycarbonyl groups having 2 to 7 carbon atoms such as methoxycarbonyl group, ethoxycarbonyl group, cyclohexyloxycarbonyl group, cyano group, t-butyl carbonate, etc. Examples include carbonate ester groups.

Of these, preferred specific examples of the organic linking group represented by R ¹ [specific examples (1) to (17)] are shown below. However, the present invention is not limited to these.

  Among the above, from the viewpoints of availability of raw materials, ease of synthesis, and solubility in various solvents, particularly preferred organic linking groups are the following groups.

R ² represents a single bond or a divalent organic linking group. The n R ^{2 s} may be the same or different.
The divalent organic linking group is a group consisting of 1 to 100 carbon atoms, 0 to 10 nitrogen atoms, 0 to 50 oxygen atoms, 1 to 200 hydrogen atoms, and 0 to 20 sulfur atoms. And may be unsubstituted or may further have a substituent.

  Specific examples of the divalent organic linking group include the following structural units or groups formed by combining the structural units.

The R ² is a single bond or a divalent composed of 1 to 50 carbon atoms, 8 or less nitrogen atoms, 25 or less oxygen atoms, 1 to 100 hydrogen atoms, and 10 or less sulfur atoms. Organic linking groups are preferred and are single bonds or divalent composed of 1 to 30 carbon atoms, 6 or less nitrogen atoms, 15 or less oxygen atoms, 1 to 50 hydrogen atoms, and 7 or less sulfur atoms. An organic linking group is more preferable, and is a single bond or a divalent group composed of 1 to 10 carbon atoms, 5 or less nitrogen atoms, 10 or less oxygen atoms, 1 to 30 hydrogen atoms, and 5 or less sulfur atoms. The organic linking group is particularly preferred.

  Among the above, when the divalent organic linking group has a substituent, examples of the substituent include carbon having 1 to 20 carbon atoms such as a methyl group and an ethyl group, a carbon such as a phenyl group and a naphthyl group. Carbon number such as acyloxy group having 1 to 6 carbon atoms such as aryl group, hydroxyl group, amino group, carboxyl group, sulfonamido group, N-sulfonylamido group, acetoxy group, etc., methoxy group, ethoxy group, etc. Alkoxy groups having 1 to 6 carbon atoms, halogen atoms such as chlorine and bromine, alkoxycarbonyl groups having 2 to 7 carbon atoms such as methoxycarbonyl group, ethoxycarbonyl group, cyclohexyloxycarbonyl group, cyano group, t-butyl carbonate, etc. Examples include carbonate ester groups.

In said formula (1), m represents 1-8. As m, 1-5 are preferable, 1-3 are more preferable, and 1-2 are especially preferable.
Moreover, n represents 2-9. As n, 2-8 are preferable, 2-7 are more preferable, and 3-6 are especially preferable.

In the formula (1), P ¹ represents a polymer skeleton and can be selected from known polymers according to the purpose and the like. The m P ¹ may be the same or different.
Among polymers, in order to constitute a polymer skeleton, a polymer or copolymer of vinyl monomers, ester polymers, ether polymers, urethane polymers, amide polymers, epoxy polymers, silicone polymers, and these Modified product or copolymer [for example, polyether / polyurethane copolymer, copolymer of polyether / vinyl monomer, etc. (any of random copolymer, block copolymer, graft copolymer) May be included). At least one selected from the group consisting of vinyl monomers, selected from the group consisting of polymers or copolymers of vinyl monomers, ester polymers, ether polymers, urethane polymers, and modified products or copolymers thereof. At least one kind is more preferable, and a polymer or copolymer of vinyl monomers is particularly preferable.
Furthermore, the polymer is preferably soluble in an organic solvent. If the affinity with the organic solvent is low, for example, when used as a pigment dispersant, the affinity with the dispersion medium is weakened, and it may not be possible to secure a sufficient adsorption layer for stabilizing the dispersion.

  Examples of the vinyl monomer include (meth) acrylic acid esters, crotonic acid esters, vinyl esters, maleic acid diesters, fumaric acid diesters, itaconic acid diesters, (meth) acrylamides, styrenes, and vinyl ethers. , Vinyl ketones, olefins, maleimides, (meth) acrylonitrile, vinyl monomers having an acidic group, and the like.

  Examples of the (meth) acrylate esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n- (meth) acrylate. Butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, amyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate , 2-ethylhexyl (meth) acrylate, t-octyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, acetoxyethyl (meth) acrylate, phenyl (meth) acrylate, (meth ) 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate (Meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid 4-hydroxybutyl, (meth) acrylic acid 2-methoxyethyl, (meth) acrylic acid 2-ethoxyethyl, (meth) acrylic acid 2- (2- (Methoxyethoxy) ethyl, 3-methoxy-2-hydroxypropyl (meth) acrylate, 2-chloroethyl (meth) acrylate, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, ( (Meth) vinyl acrylate, (meth) acrylic acid 2-phenylvinyl, (meth) acrylic acid 1-propenyl, (meth) acrylic acid allyl, (meth) acrylic acid 2-allyloxyethyl, (meth) acrylic acid propargyl, Benzyl (meth) acrylate, diethylene glycol monomethacrylate (meth) acrylate Ether, (meth) acrylic acid diethylene glycol monoethyl ether, (meth) acrylic acid triethylene glycol monomethyl ether, (meth) acrylic acid triethylene glycol monoethyl ether, (meth) acrylic acid polyethylene glycol monomethyl ether, (meth) acrylic acid Polyethylene glycol monoethyl ether, β-phenoxyethoxyethyl (meth) acrylate, nonylphenoxy polyethylene glycol (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, (meth) Trifluoroethyl acrylate, octafluoropentyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, Meth) acrylic acid tribromophenyl, (meth) tribromophenyl oxyethyl acrylate, and (meth) acrylic acid -γ- butyrolactone.

Examples of the crotonic acid esters include butyl crotonic acid and hexyl crotonic acid.
Examples of the vinyl esters include vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, and vinyl benzoate.
Examples of the maleic acid diesters include dimethyl maleate, diethyl maleate, and dibutyl maleate.
Examples of the fumaric acid diesters include dimethyl fumarate, diethyl fumarate, and dibutyl fumarate.
Examples of the itaconic acid diesters include dimethyl itaconate, diethyl itaconate, and dibutyl itaconate.

  Examples of the (meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- n-butylacryl (meth) amide, Nt-butyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-phenyl (meth) acrylamide, N-nitrophenyl acrylamide, N-ethyl-N-phenyl acrylamide, N-benzyl (meth) acrylamide, (meth) acryloylmorpholine, diacetone acrylamide , - methylol acrylamide, N- hydroxyethyl acrylamide, vinyl (meth) acrylamide, N, N- diallyl (meth) acrylamide, such as N- allyl (meth) acrylamide.

  Examples of the styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, butyl styrene, hydroxy styrene, methoxy styrene, butoxy styrene, acetoxy styrene, chlorostyrene, dichlorostyrene, bromostyrene, chloro Examples thereof include methylstyrene, hydroxystyrene protected with a group deprotectable by an acidic substance (for example, t-butyloxycarbonyl group (t-Boc) and the like), methyl vinylbenzoate, α-methylstyrene and the like.

Examples of the vinyl ethers include methyl vinyl ether, ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, methoxyethyl vinyl ether, and phenyl vinyl ether.
Examples of the vinyl ketones include methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
Examples of the olefins include ethylene, propylene, isobutylene, butadiene, and isoprene.
Examples of the maleimides include maleimide, butyl maleimide, cyclohexyl maleimide, and phenyl maleimide.

  Examples of the vinyl monomer include those described above, (meth) acrylonitrile, heterocyclic groups substituted with a vinyl group (for example, vinylpyridine, N-vinylpyrrolidone, vinylcarbazole, etc.), N-vinylformamide, N- Vinylacetamide, N-vinylimidazole, vinylcaprolactone, and the like can also be used. Further, for example, vinyl monomers having a functional group such as a urethane group, a urea group, a sulfonamide group, a phenol group, and an imide group can also be used. Such a monomer having a urethane group or a urea group can be appropriately synthesized using, for example, an addition reaction between an isocyanate group and a hydroxyl group or an amino group. Specifically, an addition reaction between an isocyanate group-containing monomer and a compound containing one hydroxyl group or a compound containing one primary or secondary amino group, or a hydroxyl group-containing monomer or primary or secondary amino group containing It can be appropriately synthesized by an addition reaction between a monomer and monoisocyanate.

Examples of the vinyl monomer having an acidic group include a vinyl monomer having a carboxyl group, a vinyl monomer having a sulfonic acid group, a vinyl monomer having a phosphoric acid group, a vinyl monomer having a phenolic hydroxyl group, and a sulfonamide group. Vinyl monomers to be used.
Examples of the vinyl monomer having a carboxyl group include (meth) acrylic acid, vinyl benzoic acid, maleic acid, maleic acid monoalkyl ester, fumaric acid, itaconic acid, crotonic acid, cinnamic acid, acrylic acid dimer, and the like. It is done. Further, addition reaction product of a monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and a cyclic anhydride such as maleic anhydride, phthalic anhydride, or cyclohexanedicarboxylic anhydride, ω-carboxy-polycaprolactone Mono (meth) acrylates can also be used. Moreover, you may use anhydride containing monomers, such as maleic anhydride, itaconic anhydride, and citraconic anhydride, as a precursor of a carboxyl group. Of these, (meth) acrylic acid is particularly preferable from the viewpoints of copolymerizability, cost, solubility, and the like.

Examples of the vinyl monomer having a sulfonic acid group include 2-acrylamido-2-methylpropanesulfonic acid.
Examples of the vinyl monomer having a phosphoric acid group include mono (2-acryloyloxyethyl ester) phosphate and mono (1-methyl-2-acryloyloxyethyl ester) phosphate.

  In the present invention, among the polymers represented by the formula (1), the polymer represented by the following formula (2) is preferable.

In the formula (2), A ² has the same meaning as A ¹ in the formula (1), and the preferred embodiment is also the same.
In the formula (2), R ³ represents an (m + n) -valent organic linking group.
The (m + n) -valent organic linking group represented by R ³ has the same meaning as R ¹ in formula (1), and the preferred embodiments thereof are also the same. Further, specific examples include the same structural unit as described above or a group formed by combining the structural units.

In the formula (2), R ⁴ and R ⁵ each independently represents a single bond or a divalent organic linking group. n R ⁴ and m R ⁵ may be the same or different independently.
The “divalent organic linking group” represented by R ⁴ and R ⁵ may be unsubstituted or substituted, and may be a linear, branched, or cyclic alkylene group, arylene group, aralkylene group. and, -O -, - S -, - C (= O) -, - N (R 19) -, - SO -, - SO 2 -, - CO 2 -, - N (R 20) SO 2 - Or a divalent group in which two or more of these groups are combined may be mentioned as a preferred example (the above R ¹⁹ and R ²⁰ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). .).

Examples of R ⁴ include linear and branched alkylene groups, aralkylene groups, and —O—, —C (═O) —, —N (R ¹⁹ ) —, —SO ₂ —, —CO ₂ —, — N (R ²⁰ ) SO ₂ — (wherein R ¹⁹ and R ²⁰ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), or a divalent group obtained by combining two or more of these groups Are more preferable, a linear or branched alkylene group, an aralkylene group, and —O—, —C (═O) —, —N (R ¹⁹ ) — (wherein R ¹⁹ represents a hydrogen atom or a carbon number of 1 to 4). Represents an alkyl group), —CO ₂ — or a divalent group in which two or more of these groups are combined is particularly preferred.

R ⁵ includes a single bond or a linear or branched alkylene group, an aralkylene group, —O—, —C (═O) —, —N (R ¹⁹ ) —, —SO ₂ —, —CO _2. —, —N (R ²⁰ ) SO ₂ — (wherein R ¹⁹ and R ²⁰ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), or a combination of two or more of these groups And a linear or branched alkylene group, an aralkylene group, and —O—, —C (═O) —, —N (R ¹⁹ ) — (wherein R ¹⁹ represents a hydrogen atom or a carbon number). represents 1-4 alkyl group), -. CO ₂ - or a divalent group formed by combining two or more of these groups are particularly preferred.

When R ⁴ and R ⁵ have a substituent, examples of the substituent include an alkyl group having 1 to 20 carbon atoms such as a methyl group and an ethyl group, and a carbon number of 6 such as a phenyl group and a naphthyl group. From 1 to 16 carbon atoms such as aryl groups, hydroxyl groups, amino groups, carboxyl groups, sulfonamido groups, N-sulfonylamido groups, acetoxy groups and the like, acyloxy groups having 1 to 6 carbon atoms, methoxy groups, ethoxy groups and the like. Alkoxy groups up to 6, halogen atoms such as chlorine and bromine atoms, alkoxycarbonyl groups having 2 to 7 carbon atoms such as methoxycarbonyl group, ethoxycarbonyl group, cyclohexyloxycarbonyl group, cyano group, t-butyl carbonate, etc. And carbonate ester groups.

In said formula (2), m represents 1-8. As m, 1-5 are preferable, 1-3 are more preferable, and 1-2 are especially preferable.
Moreover, n represents 2-9. As n, 2-8 are preferable, 2-7 are more preferable, and 3-6 are especially preferable.

Further, P ² in the formula (2) represents a polymer skeleton and can be selected from known polymers according to the purpose and the like. The preferred embodiment of the polymer, has the same meaning as P ¹ in formula (1), the same applies to its preferred embodiment.

Among the polymer compounds represented by the formula (2), in particular, R ³ is the specific example (1), (2), (10), (11), (16), or (17) R ⁴ is a single bond or a linear or branched alkylene group, an aralkylene group, and —O—, —C (═O) —, —N (R ¹⁹ ) — (wherein R ¹⁹ represents a hydrogen atom or Represents a C 1-4 alkyl group), —CO ₂ — or a divalent organic group obtained by combining two or more of these groups, wherein R ⁵ is a single bond, an ethylene group, a propylene group, or The following group (a) or (b), wherein P ² is a polymer or copolymer of a vinyl monomer, an ester polymer, an ether polymer, a urethane polymer, and a modified product thereof, and m is 1 to 1 The polymer compound having 2 and n of 3 to 6 is most preferable. In the following groups, R ²¹ represents a hydrogen atom or a methyl group, and l represents 1 or 2.

The molecular weight of the polymer compound according to the present invention is preferably 3,000-100,000, more preferably 5,000-80,000, and particularly preferably 7,000-60,000 in terms of weight average molecular weight. When the weight average molecular weight is within the above range, the effects of the multiple functional groups introduced at the polymer ends are fully exhibited, and the performance of adsorbing to the solid surface, micelle forming ability, and surface activity is excellent. To do. In particular, when the polymer compound according to the present invention is used as a pigment dispersant, good dispersibility and dispersion stability can be achieved.
The polymer compound represented by the formula (1) (including the polymer compound represented by the formula (2)) is not particularly limited, but can be synthesized by the following method. Of the following synthesis methods, the following synthesis methods such as 2, 3, 4, 5 and the like are more preferable, and the following synthesis methods such as 3, 4, 5, and the like are particularly preferable because of ease of synthesis.
1. A polymer in which a functional group selected from a carboxyl group, a hydroxyl group, an amino group and the like is introduced at the terminal, an acid halide having a plurality of functional groups (A ¹ or A ² in the above formula), or a plurality of functional groups (the above-mentioned A method in which an alkyl halide having A ¹ or A ² in the formula, or an isocyanate having a plurality of functional groups (A ¹ or A ² in the formula) is polymerized.
2. A method in which a polymer having a carbon-carbon double bond introduced at the terminal and a mercaptan having a plurality of functional groups (A ¹ or A ² in the above formula) are subjected to a Michael addition reaction.
3. A method in which a polymer having a carbon-carbon double bond introduced at a terminal thereof and a mercaptan having a plurality of functional groups (A ¹ or A ² in the above formula) are reacted in the presence of a radical generator.
4). A method in which a polymer in which a plurality of mercaptans are introduced at a terminal and a functional group in which a carbon-carbon double bond is introduced (A ¹ or A ² in the above formula) are reacted in the presence of a radical generator.
5). A method of radical polymerization of a vinyl monomer using a mercaptan compound having a plurality of functional groups (A ¹ or A ² in the above formula) as a chain transfer agent.

  Among the above, the polymer compound (especially the polymer compound represented by the formula (2)) can be synthesized, for example, by any one of the methods 2, 3, 4, and 5 above. From the viewpoint of ease, it is most preferable to synthesize by the above method 5.

  More specifically, it is preferable to perform radical polymerization using a compound represented by the following formula (3) as a chain transfer agent.

In the formula (3), R ⁶ , R ⁷ , A ³ , m, and n have the same meanings as R ³ , R ⁴ , A ² , m, and n in the formula (2), respectively. Is the same.

  Although it does not restrict | limit especially as said vinyl monomer, For example, (meth) acrylic acid esters, crotonic acid esters, vinyl esters, maleic acid diesters, fumaric acid diesters, itaconic acid diesters, (meth) acrylamides , Vinyl ethers, esters of vinyl alcohol, styrenes, (meth) acrylonitrile and the like are preferable. Examples of such include the following compounds.

  Examples of the (meth) acrylate esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n- (meth) acrylate. Butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, (meth) acrylic acid 2 -Ethylhexyl, t-octyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, acetoxyethyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate , 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate , 2- (2-methoxyethoxy) ethyl (meth) acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, benzyl (meth) acrylate, diethylene glycol monomethyl ether (meth) acrylate, (meth) Acrylic acid diethylene glycol monoethyl ether, (meth) acrylic acid triethylene glycol monomethyl ether, (meth) acrylic acid triethylene glycol monoethyl ether, (meth) acrylic acid polyethylene glycol monomethyl ether, (meth) acrylic acid polyethylene glycol monoethyl ether , Β-phenoxyethoxyethyl (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, dicyclopentenyl (meth) acrylate, disi (meth) acrylate Clopentenyloxyethyl, trifluoroethyl (meth) acrylate, octafluoropentyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, tribromo (meth) acrylate Examples thereof include phenyl and tribromophenyloxyethyl (meth) acrylate.

  Examples of the crotonic acid esters include butyl crotonic acid and hexyl crotonic acid.

  Examples of the vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, vinyl benzoate, and the like.

  Examples of the maleic acid diesters include dimethyl maleate, diethyl maleate, and dibutyl maleate.

  Examples of the fumaric acid diesters include dimethyl fumarate, diethyl fumarate, and dibutyl fumarate.

  Examples of the itaconic acid diesters include dimethyl itaconate, diethyl itaconate, and dibutyl itaconate.

  Examples of the (meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- n-butylacryl (meth) amide, Nt-butyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, Examples thereof include N, N-diethyl (meth) acrylamide, N-phenyl (meth) acrylamide, N-benzyl (meth) acrylamide, (meth) acryloylmorpholine, diacetone acrylamide and the like.

  Examples of the styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, butyl styrene, hydroxy styrene, methoxy styrene, butoxy styrene, acetoxy styrene, chlorostyrene, dichlorostyrene, bromostyrene, chloro Examples thereof include methylstyrene, hydroxystyrene protected with a group deprotectable by an acidic substance (for example, t-Boc and the like), methyl vinylbenzoate, and α-methylstyrene.

  Examples of the vinyl ethers include methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, and methoxyethyl vinyl ether.

In addition to the above compounds, (meth) acrylonitrile, heterocyclic groups substituted with vinyl groups (eg, vinylpyridine, vinylpyrrolidone, vinylcarbazole, etc.), N-vinylformamide, N-vinylacetamide, N-vinylimidazole Vinyl caprolactone can also be used.
In addition to the above compounds, vinyl monomers having a functional group such as a urethane group, a urea group, a sulfonamide group, a phenol group, and an imide group can also be used. Such a monomer having a urethane group or a urea group can be appropriately synthesized using, for example, an addition reaction between an isocyanate group and a hydroxyl group or an amino group. Specifically, an addition reaction between an isocyanate group-containing monomer and a compound containing one hydroxyl group or a compound containing one primary or secondary amino group, or a hydroxyl group-containing monomer or primary or secondary amino group containing It can be appropriately synthesized by an addition reaction between a monomer and monoisocyanate.

The above vinyl monomers may be polymerized by only one kind, or may be copolymerized by using two or more kinds together. Such a radical polymer is prepared by a known method in accordance with a conventional method for each corresponding vinyl monomer. It is obtained by polymerizing.
For example, a method (solution polymerization method) in which these vinyl monomers and a chain transfer agent are dissolved in a suitable solvent, a radical polymerization initiator is added thereto and polymerized in a solution at about 50 ° C. to 220 ° C. Obtained by using.

  Examples of suitable solvents used in the solution polymerization method can be arbitrarily selected depending on the monomers used and the solubility of the resulting copolymer. For example, methanol, ethanol, propanol, isopropanol, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methoxypropyl acetate, ethyl lactate, ethyl acetate, acetonitrile, tetrahydrofuran, dimethyl Examples include formamide, chloroform, and toluene. These solvents may be used as a mixture of two or more.

  Examples of radical polymerization initiators include azo compounds such as 2,2′-azobis (isobutyronitrile) (AIBN) and 2,2′-azobis- (2,4′-dimethylvaleronitrile), benzoyl par Peroxides such as oxides, and persulfates such as potassium persulfate and ammonium persulfate can be used.

The compound represented by the formula (3) can be synthesized by the following method or the like, but the following method 7 is more preferable because of ease of synthesis.
6). A method of converting a halide compound having a plurality of functional groups (A ¹ or A ² in the above formula) into a mercaptan compound (a method of reacting with thiourea and hydrolyzing, a method of reacting directly with NaSH, a reaction with CH ₃ COSNa And a method of hydrolyzing them).
7). Addition reaction of a compound having 3 to 10 mercapto groups in one molecule and a compound having a functional group (A ¹ or A ² in the above formula) and having a functional group capable of reacting with a mercapto group Method.

Suitable examples of the “functional group capable of reacting with a mercapto group” in Method 7 include acid halides, alkyl halides, isocyanates, and carbon-carbon double bonds.
It is particularly preferable that the “functional group capable of reacting with a mercapto group” is a carbon-carbon double bond, and the addition reaction is synthesized by a radical addition reaction. The carbon-carbon double bond is more preferably a mono- or di-substituted vinyl group in terms of reactivity with the mercapto group.

  Specific examples of the "compound having 3 to 10 mercapto groups in one molecule" [specific examples (18) to (34)] include the following compounds.

  Among the above, the following compounds are particularly preferable from the viewpoints of availability of raw materials, ease of synthesis, and solubility in various solvents.

A functional group (A ¹ or A ² in the above formula) and carbon - The compound having a carbon double bond is not particularly limited, include the following.

  For example, “the compound having 3 to 10 mercapto groups in one molecule” and the above “the acid group, the group having a basic nitrogen atom, the urea group, the urethane group, the group having a coordinating oxygen atom, carbon A compound having at least one functional group selected from the group consisting of a hydrocarbon group of 4 or more, an alkoxysilyl group, an epoxy group, an isocyanate group, and a hydroxyl group, and having a carbon-carbon double bond. The radical addition reaction product with the above-mentioned “compound having 3 to 10 mercapto groups in one molecule” and “acid group, group having basic nitrogen atom, urea group, urethane group, coordinating oxygen” A group having an atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, an epoxy group, an isocyanate group, and a hydroxyl group, and having a carbon-carbon double bond Obtained using the - (ene reaction method thiol) was dissolved compounds "a in a suitable solvent with, here by adding a radical generator, at about 50 ° C. to 100 ° C., a method of adding.

  Examples of suitable solvents used in the above method include “compounds having 3 to 10 mercapto groups in one molecule”, “acid groups, groups having basic nitrogen atoms, urea groups, urethane groups, A group having a coordinated oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, an epoxy group, an isocyanate group, and at least one functional group selected from the group consisting of a hydroxyl group, and a mercapto group The compound can be arbitrarily selected according to the solubility of the compound having a functional group capable of reacting with (for example, a carbon-carbon double bond) and the resulting radical addition reaction product. For example, methanol, ethanol, propanol, isopropanol, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methoxypropyl acetate, ethyl lactate, ethyl acetate, acetonitrile, tetrahydrofuran, dimethyl Examples include formamide, chloroform, and toluene. These solvents may be used as a mixture of two or more.

  As the radical generator, azo compounds such as 2,2′-azobis (isobutyronitrile) (AIBN) and 2,2′-azobis- (2,4′-dimethylvaleronitrile), benzoyl peroxide And persulfates such as potassium persulfate and ammonium persulfate can be used.

In the present invention, the component (C) may be used alone or in combination of two or more.
The content of the component (C) in the ink composition of the present invention is preferably 1 to 100% by weight and more preferably 5 to 70% by weight with respect to the amount of the component (B) (organic pigment) added.
When the added amount of the component (C) is 1% by weight or more, good dispersibility is obtained, and a dispersion having a large particle size (aggregated) can be suppressed. Moreover, the viscosity increase by an excess (C) component can be suppressed as it is 100 weight% or less.
In the ink composition of the present invention, a known pigment dispersant can be used in combination with the component (C) as long as the effects of the present invention are not impaired. In this case, the content of the known pigment dispersant in the ink composition is preferably 50% by weight or less, and more preferably 30% by weight or less with respect to the amount of the component (C) added. .

Examples of the known dispersants (pigment dispersants) include polymer dispersants (for example, polyamidoamine and salts thereof, polycarboxylic acids and salts thereof, high molecular weight unsaturated acid esters, modified polyurethanes, modified polyesters, modified poly (meta ) Acrylate, (meth) acrylic copolymer, naphthalenesulfonic acid formalin condensate), polyoxyethylene alkyl phosphate ester, polyoxyethylene alkylamine, alkanolamine, pigment derivative, and the like.
The pre-polymer dispersing agent can be further classified into a linear polymer, a terminal-modified polymer, a graft polymer, and a block polymer according to its structure.

  The pre-polymer dispersing agent is adsorbed on the surface of the pigment and acts to prevent reaggregation. Therefore, a terminal-modified polymer, a graft polymer, and a block polymer having an anchor site to the surface of the pigment are preferable structures. On the other hand, the pigment derivative has an effect of promoting adsorption of the polymer dispersant by modifying the surface of the pigment.

  Specific examples of the known dispersant (pigment dispersant) include “Disperbyk-101 (polyamidoamine phosphate), 107 (carboxylic acid ester), 110 (copolymer containing an acid group)”, 130, manufactured by BYK Chemie. (Polyamide), 161, 162, 163, 164, 165, 166, 170 (polymer copolymer) ”,“ BYK-P104, P105 (high molecular weight unsaturated polycarboxylic acid) ”,“ EFKA 4047, 4050, manufactured by EFKA Corporation ” 4010, 4165 (polyurethane-based), EFKA4330, 4340 (block copolymer), 4400, 4402 (modified polyacrylate), 5010 (polyesteramide), 5765 (high molecular weight polycarboxylate), 6220 (fatty acid polyester), 6745 (Phthalocyanine derivative), 6750 ( Zo pigment derivative) ”,“ Ajisper PB821, PB822 ”manufactured by Ajinomoto Fan Techno Co., Ltd.,“ Floren TG-710 (urethane oligomer) ”manufactured by Kyoeisha Chemical Co., Ltd.,“ Polyflow No. 50E, No. 300 (acrylic copolymer) ” “Disparon KS-860, 873SN, 874, # 2150 (aliphatic polycarboxylic acid), # 7004 (polyetherester), DA-703-50, DA-705, DA-725”, Kao, manufactured by Enomoto Kasei Co., Ltd. “Demol RN, N (Naphthalenesulfonic acid formalin polycondensate), MS, C, SN-B (aromatic sulfonic acid formalin polycondensate)”, “Homogenol L-18 (polymer polycarboxylic acid)”, “Emulgen 920, 930, 935, 985 (polyoxyethylene nonylphenyl ether)”, “Aceta Min 86 (stearylamine acetate), Lubrizol "Solsperse 5000 (phthalocyanine derivative), 22000 (azo pigment derivative), 13240 (polyesteramine), 3000, 17000, 27000 (polymer having a functional part at the end) , 24000, 28000, 32000, 38500 (graft type polymer) ”,“ Nikkor T106 (polyoxyethylene sorbitan monooleate), MYS-IEX (polyoxyethylene monostearate) ”manufactured by Nikko Chemical Co., Ltd., and the like.

(D) Radical polymerization initiator The ink composition of the present invention contains (D) 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, 4,734,444, 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′- Peroxide 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 compounds include those disclosed in 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 dicyclopentadienyl-Ti-di-chloride, dicyclopentadienyl-Ti-bis-phenyl, and dicyclopentadienyl-Ti-bis-2,3,4,5. , 6-pentafluorophen-1-yl, dicyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, dicyclopentadienyl-Ti-bis-2,4 , 6-Trifluorophen-1-yl, dicyclopentadienyl-Ti-2,6-difluorophen-1-yl, dicyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl Dimethylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, dimethylcyclopentadienyl-Ti-bis-2,3,5 -Tetrafluorophen-1-yl, dimethylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) bis (2,6-difluoro-3- (pyri- 1-yl) phenyl) titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (methylsulfonamido) phenyl] titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3 -(N-butylbialoylamino) 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 amount of radical polymerization initiator used is preferably 0.01 to 35% by weight, more preferably 0, based on the total amount of polymerizable compounds containing N-vinyl lactams. 0.5 to 20% by weight, more preferably 1.0 to 15% by weight. When the amount used is 0.01% by weight or more, the ink composition can be sufficiently cured, and when it is 35% by weight or less, a cured film having a uniform degree of curing can be obtained.
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 weight ratio of radical polymerization initiator: sensitizer to 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.

(E) Ethylenically unsaturated monomer represented by formula (I) or formula (II) The ink composition of the present invention comprises an ethylenically unsaturated monomer represented by formula (I) or formula (II) (hereinafter referred to as “ethylenically unsaturated monomer”). , (Also referred to as component (E)). 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.
An end for coupling with 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 coloring material, the end bonded to the alicyclic hydrocarbon structure of X ¹ in formula (I) or formula (II) is preferably an oxygen atom, and ether 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 a 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 ethylenically unsaturated monomer represented by the formula (I) or the formula (II) is preferably an ethylenically unsaturated 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 represents 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 exists. R ⁴ , t ⁵ R ⁵ , and u R ⁶ 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 are the same as the substituents 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 ethylenically unsaturated 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 ethylenically unsaturated monomer represented by formula (I) or formula (II), preferred specific examples of monofunctional methacrylates are shown below.

  As the ethylenically unsaturated 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 (I) or the formula (II) are shown below.

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

  The ethylenically unsaturated monomer represented by formula (I) or formula (II) in the ink composition of the present invention is preferably 0.5 to 90 parts by weight with respect to the total amount of the ink composition. More preferably, it is -70 weight part, It is further more preferable that it is 10-50 weight part. It is preferable for it to be in the above range since the curability is excellent and the viscosity is moderate.

  Of the ethylenically unsaturated 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. More preferably. 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 1 to 90 parts by weight, more preferably 2 to 70 parts by weight, and still more preferably 10 to 50 parts by weight. . Within the above range, the curability and flexibility are excellent, and the viscosity is appropriate, which is preferable.

  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 0.5-15 weight part, It is more preferable that it is 0.5-10 weight part, It is further more preferable that it is 0.5-5 weight part. 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 more preferably 0 to 5% by weight. Is more preferable. Within the above range, an ink composition excellent in flexibility of a cured film can be provided.

(F) Phenoxyethyl (meth) acrylate The ink composition of the present invention preferably contains phenoxyethyl acrylate and / or phenoxyethyl methacrylate, and more preferably contains phenoxyethyl acrylate.
The (F) phenoxyethyl (meth) acrylate in the ink composition of the present invention is preferably 0.1 to 40 parts by weight, more preferably 1 to 30 parts by weight with respect to the total amount of the ink composition. Preferably, it is 2 to 20 parts by weight. It is preferable for it to be in the above range since it is excellent in curability and has an appropriate viscosity.

(G) Other radical polymerizable compounds In the present invention, in addition to the (A) component, the (E) component, and the (F) component, other radical polymerizable compounds (hereinafter also simply referred to as “radical polymerizable compounds”, Needless to say, it means a radically polymerizable compound excluding the component (A), the component (E) and the component (F).
It is preferable to use a radically polymerizable compound in combination 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-acryloyloxyethyl phthalate, tetramethylol methane Triacrylate, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, dimethylol tricyclodecane diacrylate, 2-acryloyloxyethyl succinate , Modified glycerin triacrylate, bisphenol A diglycidyl ether acrylic acid adduct, modified bisphenol A diacrylate, 2-acryloyloxyethyl hexahydrophthalic acid, dipentaerythritol hexaacrylate, pentaerythritol triacrylate 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 urethane prepolymer Is More specifically, Yamashita Junzo “Cross-linking agent handbook” (1981, Taiseisha); Kato Kiyomi ed. “UV / EB curing handbook (raw material)” (1985, Polymer publication society); Articles on the application and market of UV / EB curing technology, p. 79 (1989, CMC); Eiichiro Takiyama's “Polyester Resin Handbook” (1988, Nikkan Kogyo Shimbun), etc. These radically polymerizable or crosslinkable monomers, oligomers and polymers 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, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, and cyclohexanedimethanol. Di- or trivinyl ether compounds such as divinyl ether and trimethylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl Monovinyl ether compounds such as ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, octadecyl vinyl ether, ethylene glycol monovinyl ether, triethylene glycol monovinyl ether, hydroxyethyl monovinyl ether, hydroxynonyl monovinyl ether, etc. Is mentioned.
Of these vinyl ether compounds, divinyl ether compounds and trivinyl ether compounds are preferred, and divinyl ether compounds are particularly preferred from the viewpoints of curability, adhesion, and surface hardness. 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 compounds described above have high reactivity, low viscosity, and excellent adhesion to a recording medium.

  The content of the other radical polymerizable compound in the ink composition is preferably 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.

(Cationically polymerizable monomer)
Examples of the cationic polymerizable monomer that can be used as the polymerizable compound include, for example, JP-A Nos. 6-9714, 2001-31892, 2001-40068, 2001-55507, 2001-310938, and 2001-310937. An epoxy compound, a vinyl ether compound, an oxetane compound and the like described in each publication such as JP-A No. 2001-220526 are preferable.

The epoxy compound may be a monofunctional epoxy compound or a polyfunctional epoxy compound.
Examples of the monofunctional epoxy compound include phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, and 1,3-butadiene mono. Oxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3-vinylcyclohexene oxide, etc. Can be mentioned.

Examples of the polyfunctional epoxy compound include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, and brominated bisphenol S diglycidyl. Ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2 -(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexyl) Methyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6 '-Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylenebis (3,4-epoxycyclohexanecarboxylate) , Epoxyhexahydrophthalate dioctyl, epoxyhexahydrophthalate di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, Serine triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8-di Examples thereof include epoxy octane, 1,2,5,6-diepoxycyclooctane, and the like.
Among these epoxy compounds, an aromatic epoxy compound and an alicyclic epoxy compound are preferable, and an alicyclic epoxy compound is particularly preferable in terms of excellent curing speed.

The vinyl ether compound may be a monofunctional vinyl ether compound or a polyfunctional vinyl ether compound.
Examples of the monofunctional vinyl ether compound include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, cyclohexyl methyl vinyl ether, 4 -Methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl Ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloro Examples thereof include ethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxy polyethylene glycol vinyl ether, and the like.

Examples of the polyfunctional vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, and bisphenol F alkylene oxide. Divinyl ethers such as divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol Hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide addition And polyfunctional vinyl ethers such as pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.
Among these vinyl ether compounds, di- or trivinyl ether compounds are preferable and divinyl ether compounds are particularly preferable in terms of curability, adhesion to a recording medium, surface hardness of the formed image, and the like.

The oxetane compound means a compound having an oxetane ring, and preferred examples thereof include known oxetane compounds described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217.
In the present invention, the oxetane compound is preferably a compound having 1 to 4 oxetane rings in its structure. When such a compound is used, it becomes easy to maintain the viscosity of the ink composition in a good handling property range, and it is possible to obtain high adhesion of the cured ink to the recording medium. Is advantageous.

The oxetane compound may be a monofunctional oxetane compound or a polyfunctional oxetane compound.
Examples of the monofunctional oxetane compound include 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, (3-ethyl-3-oxetanylmethoxy) methylbenzene, 4-fluoro -[1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, 4-methoxy- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, [1- (3-ethyl-3-oxetanyl) Methoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl-3-oxetanylmethyl) Ether, 2-ethylhexyl (3-ethyl-3-oxe) Nylmethyl) ether, ethyldiethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, Dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tetrabromophenoxy Ethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether, pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, and the like.

  Examples of the polyfunctional oxetane compound include 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)). Bis (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1, 3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether, tri Ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3- Til-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3 -Ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl- 3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-e Ru-3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentane Kis (3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A Bis (3-ethyl-3-oxetanylmethyl) ether, EO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis (3- Ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl) ether, and the like.

In addition to these, as the oxetane compound, compounds described in detail in paragraphs [0021] to [0084] of JP-A-2003-341217 can also be suitably used in the present invention.
Among the oxetane compounds described above, in the present invention, a compound having 1 to 2 oxetane rings is preferable from the viewpoint of viscosity and adhesiveness of the ink composition.

  When a cationically polymerizable compound is used in the ink composition of the present invention, the above-mentioned cationically polymerizable compound may be used alone or in combination of two or more. From the standpoint of effectively suppressing the shrinkage, it is preferable to use at least one oxetane compound in combination with at least one compound selected from an epoxy compound and a vinyl ether compound.

(Cationic polymerization initiator)
In the ink composition of the present invention, when a cationic polymerizable compound is used in combination, a cationic polymerization initiator is preferably used in combination.

First, B (C ₆ F ₅ ) ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ and CF ₃ SO ₃ ⁻ salts of aromatic onium compounds such as diazonium, ammonium, iodonium, sulfonium and phosphonium are listed. be able to. Secondly, sulfonated products that generate sulfonic acid can be mentioned. Thirdly, a halide that generates hydrogen halide can also be used. Fourthly, iron arene complexes can be mentioned.

(Other ingredients)
The ink composition of the present invention may contain other components appropriately selected according to the purpose in addition to the components described above.
Examples of the other components include sensitizers, co-sensitizers, resins, surfactants, ultraviolet absorbers, antioxidants, anti-fading agents, ejection stabilizers, adhesion improvers, leveling additives, mats. Agents and the like. These may be used individually by 1 type and may use 2 or more types together.

<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 inkjet.
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.
Examples of preferred sensitizers 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 (for example, thionine, methylene blue, toluidine blue), acridines (for example, acridine orange, chloroflavin, acriflavine), anthraquinones (for example, anthraquinone), squalium (for example, Squalium), coumarins (for example, 7-diethylamino-4-methylcoumarin).

  More preferable examples of the sensitizer 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 represent 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 nonmetallic atomic group, and 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 sensitizing dye to actinic radiation or suppressing the 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, page 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Laid-Open No. 51-82102. 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-H described in JP-A-8-54735 , Ge—H compounds and the like.
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 generally 0.05 to 4% by weight with respect to the weight of the entire ink composition. preferable.

<Surfactant>
A surfactant is preferably added to the ink composition of the present invention in order to impart stable ejection properties for a long time.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as 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. An organic fluoro compound may be used in place of 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 content of the surfactant in the ink composition of the present invention is appropriately selected depending on the purpose of use, but is preferably 0.0001 to 1% by weight with respect to the weight of the entire ink composition.

<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-58-185679, JP-A-61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194843, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492 and 56-21141 Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP The triazine compounds described in JP-A-8-501291, Research Disclosure No. Examples thereof include compounds described in US Pat. No. 24239, 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 generally it 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 anti-fading agent include nickel complexes and zinc complexes. No. 17643, Nos. VII to I, J. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .
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 the 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 based on 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.

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 the tackifier, specifically, a high molecular weight adhesive polymer described in JP-A-2001-49200, 5-6p (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms). An ester with an alcohol having, an ester of (meth) acrylic acid with an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer comprising an ester of (meth) acrylic acid with 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, the viscosity at 25 ° C. of the ink composition is preferably 3 to 50 mPa · sec, more preferably 5 mPa · s to 40 mPa · s, and even more preferably 7 mPa · s in consideration of dischargeability. ˜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 viscosity can be measured using, for example, a conical plate type rotational viscometer (E type viscometer).

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 surface tension can be measured using, for example, a Wilhelmy method surface tension meter or a Du Nouy surface tension meter.

<Manufacturing>
There is no restriction | limiting in particular as a manufacturing method of the ink composition of this invention, According to the objective, it can select suitably, For example, it can manufacture by mixing each above-mentioned component. In addition, the said mixing can be performed according to a well-known method using a well-known mixer etc.

<Use>
The ink composition of the present invention can be suitably used as an ink for various image recordings, and can be particularly suitably used as an ink composition for inkjet recording. In this case, the ink composition is printed on a recording medium by an ink jet printer, and then the printed ink composition (recorded image) is irradiated with the actinic radiation to be cured and image recording is performed. .
The image recorded matter (printed matter) obtained using the ink composition of the present invention is excellent in the strength of the image portion because the image portion is cured by irradiation with the active radiation such as ultraviolet rays. Therefore, in addition to image recording (image formation), it can be suitably used for various applications such as formation of an ink receiving layer (image portion) of a lithographic printing plate.

(Inkjet recording method and inkjet recording apparatus)
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.

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

<Inkjet recording apparatus>
There is no restriction | limiting in particular as an inkjet recording device 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 preferably has a multi-size dot of 1 to 100 pl, more preferably 8 to 30 pl, preferably 320 × 320 to 4,000 × 4,000 dpi, more preferably 400 × 400 to 1,600 ×. It can be driven so as to 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 at each piping site and perform heating control according to the ink flow rate and the environmental temperature. The temperature sensor can be provided near the ink supply tank and the nozzle of the inkjet head. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of thermal 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, the step (b ¹ ) 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 accelerated. 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 sensitizing dye, 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 that the exposure surface illuminance is preferably 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. When 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, is 50 to 800 mW / cm ² It is particularly preferred.

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 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, since the ink can be exposed to the porous recording medium before the ink penetrates to a deep portion where the light source does not reach, the residual unreacted monomer can be suppressed.
Further, the curing may be completed by another light source that is not driven. International Publication No. 99/54415 pamphlet discloses a method using an optical fiber or a method of irradiating a recording unit with UV light by applying a collimated light source to a mirror surface provided on the side of the head unit as an irradiation method. Such a curing method can also be applied to the ink jet recording method of the present invention.

By adopting the ink jet recording method as described above, the dot diameter of the landed ink 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.
In this manner, 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.

<Recording medium>
The recording medium on which an image is recorded by discharging the ink composition of the present invention is not particularly limited and can be appropriately selected according to the purpose. Papers such as ordinary uncoated paper and coated paper Examples thereof include various non-absorbable resin materials used for so-called soft packaging, or resin films obtained by molding the non-absorbent resin materials. As the resin film, for example, PET film, OPS film, OPP film, ONy film, PVC film, PE film, TAC film, polycarbonate film, acrylic film, ABS film, polyacetal film, PVA film, rubber film, Etc. Further, metals, glasses and the like can be used as the recording medium.

(Printed matter)
What was obtained by curing the ink composition of the present invention is the printed material of the present invention, and the printed material is preferably a material obtained by discharging and curing the ink composition of the present invention on the recording medium. . At this time, it is more preferable that the ejection is performed by ink jet recording using an ink jet printer.
In the printed matter of the present invention, the ink composition used for image recording is the ink composition of the present invention, and contains fine pigment particles uniformly and stably dispersed. It is a high image, excellent in weather resistance, and can be suitably used in a wide range of fields.

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.
・ IRGALITE BLUE GLVO (Cyan Pigment, Ciba Specialty Chemicals (CSC))
・ CINQUASIA MAGENTA RT-335 D (magenta pigment, manufactured by CSC)
・ NOVOPERM YELLOW H2G (yellow pigment, manufactured by Clariant)
・ SPECIAL BLACK 250 (black pigment, manufactured by CSC)
・ KRONOS2300 (white pigment, manufactured by KRONOS)
・ Solsperse 36000 (dispersant, manufactured by Noveon)
・ Fancrill 512A (equivalent to exemplary compound M-11, manufactured by Hitachi Chemical Co., Ltd.)
・ N-vinylcaprolactam (manufactured by Aldrich)
Actilane 421 (propoxylated neopentyl glycol diacrylate, manufactured by Acros)
NK ester AMP-10G (phenoxyethyl acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)
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 CSC)
-BYK-307 (surfactant, manufactured by BYK Chemie)
-FIRSTCURE ITX (sensitizer, manufactured by Chem First)

(Synthesis of polymer compound represented by formula (1))
[Synthesis of mercaptan compound having functional group A ¹ ]
As shown below, chain transfer agents B-1 and B-2 were synthesized.

(Synthesis Example B-1)
Dipentaerythritol tetrakis (3-mercaptopropionate) [DPMP; manufactured by Sakai Chemical Industry Co., Ltd.] 7.83 parts, and the following compound having a functional group A ¹ and having a carbon-carbon double bond (A-1) 6.51 parts was dissolved in 33.45 parts of 1-methoxy-2-propanol and heated to 70 ° C. under a nitrogen stream. To this, 0.06 part of 2,2′-azobis (2,4-dimethylvaleronitrile) [V-65, manufactured by Wako Pure Chemical Industries, Ltd.] was added and heated for 3 hours. Furthermore, 0.06 part of V-65 was added and reacted at 70 ° C. for 3 hours under a nitrogen stream. By cooling to room temperature, the following 30% solution of the mercaptan compound (chain transfer agent B-1) according to the present invention was obtained.

(Synthesis Example B-2)
In Synthesis Example B-1, 6.51 parts of compound (A-1) having functional group A ¹ and having a carbon-carbon double bond, 33.45 parts of 1-methoxy-2-propanol Except that the compound (A-2) having a functional group A ¹ and a carbon-carbon double bond was changed to 5.80 parts and 31.81 parts of 1-methoxy-2-propanol. In the same manner as -1, a 30% solution of the mercaptan compound (chain transfer agent B-2) according to the present invention shown below was obtained.

<Synthesis of polymer compounds>
Subsequently, the polymer compound of the present invention described above was synthesized as shown below.

(Synthesis Example C-1)
A mixed solution of 19.11 parts of a 30% solution of chain transfer agent B-1 described in Synthesis Example B-1 and 20 parts of methyl methacrylate was heated to 80 ° C. under a nitrogen stream. To this, 0.013 part of 2,2′-azobis (isobutyronitrile) [AIBN, manufactured by Wako Pure Chemical Industries, Ltd.] was added and heated for 3 hours. Furthermore, 0.013 part of AIBN was added and reacted at 80 ° C. for 3 hours under a nitrogen stream. Then, it cooled to room temperature and diluted with acetone. After reprecipitation using a large amount of methanol, vacuum drying is performed to obtain 13 parts of a solid of the polymer compound (C-1: polystyrene-equivalent weight average molecular weight 12,000) according to the present invention shown below. It was.

(Synthesis Example C-2)
In Synthesis Example C-1, Synthesis Example C-1 except that 19.11 parts of a 30% solution of chain transfer agent B-1 were changed to 9.56 parts and 0.013 parts of AIBN were changed to 0.007 parts. In the same manner as described above, 14 parts of a solid compound (C-2: weight average molecular weight 20,000 in terms of polystyrene) according to the present invention shown below was obtained.

(Synthesis Example C-3)
In Synthesis Example C-1, except that 20 parts of methyl methacrylate were changed to 19.5 parts of butyl methacrylate and 8.5 parts of 2-hydroxyethyl methacrylate, the same as in Synthesis Example C-1. Then, 13 parts of a solid of the polymer compound according to the present invention (C-3: weight average molecular weight 13,000 in terms of polystyrene) shown below was obtained.

(Synthesis Example C-4)
The same as in Synthesis Example C-1, except that 19.11 parts of chain transfer agent B-1 were changed to 18.18 parts of chain transfer agent B-2 in Synthesis Example C-1. 11 parts by weight of a solid of a polymer compound (C-4: polystyrene equivalent weight average molecular weight 13,000) was obtained.

(Synthesis Example C-5)
In Synthesis Example C-1, 19.11 parts of chain transfer agent B-1 was changed to 18.1 parts by weight of chain transfer agent B-2, and 20 parts of methyl methacrylate was changed to 19.5 parts of n-butyl methacrylate. The polymer compound shown below (C-5: weight average molecular weight of 16,000 in terms of polystyrene) was the same as in Synthesis Example C-1, except that the amount was changed to 8.5 parts of 2-hydroxyethyl methacrylate. 11 parts by weight of a solid was obtained.

(Preparation of mill base A1)
IRGALITE BLUE GLVO 300 parts by weight Actilane 421 (acrylate monomer manufactured by Akcros) 500 parts by weight Polymer compound (C-1) 200 parts by weight The above components 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.

  Mill bases A2 to A5, B1 to B4, and C1 were prepared in the same manner as the mill base A1 except that the pigments and the polymer compounds were changed to the pigments and polymer compounds shown in Table 1 below.

Example 1
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 A1 6.0 parts ・ Fancrill 512A 35.5 parts ・ N-vinylcaprolactam 25.0 parts ・ NK ester AMP-10G 20.0 parts ・ FIRSTCURE ST-1 0.05 part ・ Lucirin TPO (BASF Corporation) 8.5 parts-Benzophenone (photoinitiator) 3.0 parts-IRGACURE 184 (CSC photoinitiator) 2.0 parts-BYK-307 (BYK Chemie surfactant) 0. 05 copies

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability and N-vinylcaprolactam degradability are shown in Table 2. Table 2 shows the evaluation results of image flexibility and adhesion before and after storage.

(Example 2)
The following components were stirred with a high-speed water-cooled stirrer to obtain a magenta UV inkjet ink. The viscosity was 19 mPa · s.
(Magenta ink composition)
・ Magenta mill base A2 12.0 parts ・ Fancrill 512A 36.4 parts ・ N-vinylcaprolactam 25.0 parts ・ NK ester AMP-10G 14.0 parts ・ FIRSTCURE ST-1 0.05 part ・ Lucirin TPO (BASF Corporation) 8.5 parts-Benzophenone (photoinitiator) 3.0 parts-IRGACURE 184 (CSC photoinitiator) 2.0 parts-BYK-307 (BYK Chemie surfactant) 0. 05 copies

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability and N-vinylcaprolactam degradability are shown in Table 2. Table 2 shows the evaluation results of image flexibility and adhesion before and after storage.

(Example 3)
The following components were stirred with a high-speed water-cooled stirrer to obtain a yellow UV inkjet ink. The viscosity was 19 mPa · s.
(Yellow color ink composition)
・ Yellow mill base A3 12.0 parts ・ Fancrill 512A 36.4 parts ・ N-vinylcaprolactam 25.0 parts ・ NK ester AMP-10G 14.0 parts ・ FIRSTCURE ST-1 0.05 part ・ Lucirin TPO (BASF Corporation) 8.5 parts-Benzophenone (photoinitiator) 3.0 parts-IRGACURE 184 (CSC photoinitiator) 2.0 parts-BYK-307 (BYK Chemie surfactant) 0. 05 copies

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability and N-vinylcaprolactam degradability are shown in Table 2. Table 2 shows the evaluation results of image flexibility and adhesion before and after storage.

Example 4
The following components were stirred with a high-speed water-cooled stirrer to obtain a black UV inkjet ink. The viscosity was 17 mPa · s.
(Black ink composition)
・ Black mill base A4 6.0 parts ・ Fancrill 512A 36.4 parts ・ N-vinylcaprolactam 25.0 parts ・ NK ester AMP-10G 20.0 parts ・ FIRSTCURE ST-1 0.05 parts ・ Lucirin TPO (BASF Corporation) 8.5 parts-Benzophenone (photoinitiator) 3.0 parts-IRGACURE 184 (CSC photoinitiator) 2.0 parts-BYK-307 (BYK Chemie surfactant) 0. 05 copies

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability and N-vinylcaprolactam degradability are shown in Table 2. Table 2 shows the evaluation results of image flexibility and adhesion before and after storage.

(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 A5 31.0 parts ・ Fancrill 512A 27.4 parts ・ N-vinylcaprolactam 18.0 parts ・ NK ester AMP-10G 10.0 parts ・ FIRSTCURE ST-1 0.05 part ・ Lucirin TPO (BASF Corporation) 8.5 parts-Benzophenone (photoinitiator) 3.0 parts-IRGACURE 184 (CSC photoinitiator) 2.0 parts-BYK-307 (BYK Chemie surfactant) 0. 05 parts-FIRSTCURE ITX 1.0 part

(Evaluation of ink)
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability and N-vinylcaprolactam degradability are shown in Table 2. Table 2 shows the evaluation results of image flexibility and adhesion before and after storage.

(Examples 6 to 9 and Comparative Example 1)
In the same formulation as in Example 5, only the mill base was changed to B1 to B4 and C1, and an ink composition was prepared.
Ink jet recording was performed using the obtained ink composition. The evaluation results of curability and N-vinylcaprolactam degradability are shown in Table 2. Table 2 shows the evaluation results of image flexibility and adhesion before and after storage.

(Comparative Example 2)
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 A5 31.0 parts Actylene 421 45.4 parts NK ester AMP-10G 10.0 parts FIRSTCURE ST-1 0.05 parts Lucirin TPO (BASF photoinitiator) 8.5 parts Benzophenone (photoinitiator) 3.0 parts IRGACURE 184 (CSC photoinitiator) 2.0 parts BYK-307 (BYK Chemie surfactant) 0.05 parts FIRSTCURE ITX 1.0 part

  Further, ink jet recording was performed using the obtained ink composition. The evaluation results of curability and N-vinylcaprolactam degradability are shown in Table 2. Table 2 shows the evaluation results of image flexibility and adhesion before and after storage.

<Evaluation conditions>
The ink compositions of Examples and Comparative Examples were held at 60 ° C. for 4 weeks.
Using these ink compositions, the curability, the decomposition ratio of N-vinylcaprolactam, the flexibility, and the adhesion were evaluated by the following evaluation methods.
The decomposition ratio of N-vinylcaprolactam in the ink composition was measured by liquid chromatography, and the fluctuation of the peak area of N-vinylcaprolactam from the initial state was confirmed.

<Inkjet image recording method>
Using the ink before aging and each ink composition after aging, recording on a recording medium was performed using an inkjet recording experimental apparatus having a piezo-type 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 nozzle of the ink jet head, respectively, and temperature control was performed so that the nozzle portion was 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 landed on the recording medium. . Further, the integrated light amount irradiated to the image was set to 4,500 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.

<Method of measuring curing sensitivity (curability)>
In accordance with the inkjet recording method, a 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.
3: No stickiness.
2: There is a little stickiness.
1: The ink is not hard enough to transfer to the hand.

<Method for measuring liquid chromatography>
The ink composition before and after aging was measured using a liquid chromatography device manufactured by Waters and a column RP-18 for liquid chromatography manufactured by Kanto Chemical. The peak areas of the N-vinylcaprolactam peak before and after aging were compared, and the reduction ratio (decomposition ratio) was calculated. It shows that decomposition | disassembly can be suppressed, so that a decreasing rate is small.

<Flexibility evaluation method: Bending test>
In this example, a bending test was performed as a method for evaluating the flexibility of the cured film before and after storage.
According to the inkjet ink jet image recording method, an ester film E5000 (film thickness 125 μm, manufactured by Toyobo Co., Ltd.) was used as a recording medium, and three solid images having an average film thickness of 12 μm, 24 μm, and 36 μm were drawn. In the bending test, the recording material on which the image was formed was bent once at 25 ° C. and evaluated by the presence or absence of cracks in the image area. In general, when the average film thickness is increased, distortion applied to the image portion when the image portion is bent increases, and cracks are likely to occur. That is, by testing whether the image portion is cracked with a thicker film thickness, a measure of flexibility can be obtained.
The evaluation criteria are as follows.
4: Cracks do not occur in samples having an average film thickness of 12 μm, 24 μm, and 36 μm.
3: Cracks do not occur in samples having an average film thickness of 12 μm and 24 μm.
2: Cracks do not occur in the sample having an average film thickness of 12 μm, but cracks occur in the bent portion of the image portion in the sample having an average film thickness of 24 μm.
1: In all samples having an average film thickness of 12 μm, 24 μm, and 36 μm, cracks occur in the bent portion of the image portion.

<Base material adhesion evaluation method: cross hatch test (EN ISO 2409)>
Using PET (ester film E5000, film thickness 125 μm, manufactured by Toyobo Co., Ltd.) as a recording medium, a solid image having an average film thickness of 12 μm was drawn on each substrate in accordance with the inkjet ink jet image recording method. Thereafter, a cross-hatch test (EN ISO 2409) was performed on each printed matter.

<Viscosity measurement method>
In this example, the viscosity 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>
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 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 (manufactured by Phoenix Electric) was used. There was no missing dot in the obtained image, and a bright image with a thickness of 12 μm could be drawn. The evaluation results of curability and N-vinylcaprolactam degradability are shown in Table 2. Table 2 shows the evaluation results of image flexibility and adhesion before and after storage.

As is clear from Table 2, N-vinylcaprolactam, which is an N-vinyllactam, is decomposed by combining with the conventional dispersant (acidic) exemplified in Comparative Example 1, and the decomposition is accelerated by the thermo aging. The By decomposing the monomer, the material that is originally polymerized remains as a non-polymerizable component (low molecular weight compound), so that the curability and adhesion deteriorate.
On the other hand, the polymer dispersant represented by the formula (1) contains an acidic group, but has only a polymer terminal, and has an acid value that is negligible compared to a normal polymer dispersant, and N-vinyl lactams. Therefore, it is possible to produce a stable ink composition that can be effectively adsorbed on the pigment surface and has little fluctuation in viscosity over time.
Furthermore, N-vinyl in an acrylate monomer ((E) an ethylenically unsaturated monomer represented by formula (I) or formula (II), (F) phenoxy (meth) acrylate)) which is very slightly acidic. Although degradation of lactam monomers is sometimes promoted, such an adverse effect is not observed in the ink composition of the present invention.

Claims (9)

(A) N-vinyl lactams,
(B) a pigment,
(C) a polymer compound represented by the following formula (1), and
(D) An inkjet ink composition comprising a radical polymerization initiator.

(In the formula, R ¹ represents an (m + n) -valent organic linking group, R ² represents a single bond or a divalent organic linking group. A ¹ represents an acidic group, a group having a basic nitrogen atom, urea. Monovalent organic having a group selected from the group consisting of a group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, an epoxy group, an isocyanate group, and a hydroxyl group It represents a radical, n pieces of a ¹ may be the same, may be different .m represents 1 to 8, n represents 2 to 9, m + n is .P ¹ satisfying 3-10 high Represents molecular skeleton.) The inkjet ink composition according to claim 1, wherein the polymer compound is represented by the following formula (2).

(Wherein R ³ represents an (m + n) -valent organic linking group, and R ⁴ and R ⁵ each independently represents a single bond or a divalent organic linking group. A ² represents an acidic group or a basic group. Selected from the group consisting of a group having a nitrogen atom, a urea group, a urethane group, a group having a coordinating oxygen atom, a hydrocarbon group having 4 or more carbon atoms, an alkoxysilyl group, an epoxy group, an isocyanate group, and a hydroxyl group Represents a monovalent organic group having a group, and n A ² may be the same or different, m represents 1 to 8, n represents 2 to 9, and m + n represents 3 to 10 P ² represents a polymer skeleton.) (E) The ink composition for inkjet according to claim 1 or 2, comprising an ethylenically unsaturated monomer represented by formula (I) or formula (II).

(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 for inkjet according to any one of claims 1 to 3, comprising (F) phenoxyethyl (meth) acrylate.   The inkjet according to any one of claims 1 to 4, wherein the pigment is at least one selected from the group consisting of a yellow pigment, a magenta pigment, a cyan pigment, a green pigment, an orange pigment, a black pigment, and a white pigment. Ink composition.   The inkjet ink composition according to any one of claims 1 to 5, wherein the pigment is at least one selected from the group consisting of a yellow pigment, a magenta pigment, a cyan pigment, a black pigment, and a white pigment. (A ¹⁾ onto a recording medium, a step of discharging the ink composition according to any one claims 1-6 and,
(B ¹ ) An inkjet recording method comprising a step of irradiating the discharged ink composition with active radiation to cure the ink composition. The actinic radiation is an ultraviolet ray irradiated by a light emitting diode that generates an ultraviolet ray 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. The inkjet recording method according to claim 7.   Printed matter recorded by the ink jet recording method according to claim 7 or 8.