JP2010235684A - Ink composition, ink jet recording method and printed matter - Google Patents

Abstract

【選択図】なしThe present invention provides an ink composition capable of obtaining a cured film having excellent curability and safety, and excellent adhesion and flexibility.
(A) a compound represented by formula (A-1) or (A-2), (B) an ethylenically unsaturated compound having an alicyclic skeleton, (C) other polymerizable compound, And (D) a polymerization initiator is contained, and the compound represented by the formula (A) and the formula (A-2) is contained in an amount of 3% by weight or more based on the total weight of the ink composition. An ink composition. (R ¹ represents a hydrogen atom or a methyl group, R ² and R ³ represent a methylene group or an ethylene group, R ⁴ represents a hydrogen atom or an alkyl group, and R ⁵ and R ⁶ represent a hydrogen atom or an alkyl group. , L ¹ represents a divalent linking group.)

[Selection figure] None

Description

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

  At present, when ink is ejected onto a non-water-absorbing recording medium such as plain paper or plastic by an ink jet printer, high sensitivity of the ink and fixing property to the recording medium are important issues. ing.

  Developments have been made in order to improve the fixability to recording media. For swellable substrates (PVC, polycarbonate), N-vinyl compounds such as N-vinylcaprolactam (NVC) are used as an example of fixing improvement by slightly dissolving the surface of the recording medium (anchor effect). (Patent Document 1). However, surface uneven distribution of NVC, which is considered to be caused by poor copolymerizability between the acrylate monomer and NVC, results in an increase in ink curing surface energy. As a result, the ink wettability is reduced (repelled) on the cured ink film, and the image quality is deteriorated.

  Further, as a fixability improvement for non-swellable substrates (PP, PE, PET, Acrl), a reduction in volume shrinkage of the ink cured film has been proposed. For the purpose of improving the adhesion, a means for increasing the acrylic equivalent can be cited as a means for reducing the volume shrinkage. In general, in order to increase the acrylic equivalent, it is necessary to introduce a substituent having a large molecular weight into the side chain substituent of the polymerizable compound.

  On the other hand, as a composition suitable as an inkjet ink, Patent Document 2 discloses a compound (A) having one or more (meth) acrylate groups and one or more vinyl ether groups in one molecule, and 1 An active energy ray-curable composition comprising a compound (B) having one or more (meth) acrylate groups and one or more hetero 5-membered ring structures in the molecule is disclosed. Yes. Patent Document 3 discloses a photocurable inkjet ink containing a specific photopolymerization initiator and a polymerizable monomer having a thermosetting functional group.

JP 2008-201876 A Japanese Patent Laid-Open No. 2004-224841 JP 2008-214607 A

  The problems to be solved by the present invention include an ink composition that is excellent in curability and safety, a cured film excellent in adhesion and flexibility, an ink jet recording method using the ink composition, and a printed matter. Is to provide.

The above problems of the present invention have been solved by means described in the following <1> to <10>.
<1> (A) a compound represented by formula (A-1) and / or formula (A-2), (B) an ethylenically unsaturated compound having an alicyclic skeleton, (C) other polymerizable compound And (D) a polymerization initiator, and the compound represented by the formula (A-1) and the formula (A-2) is contained in an amount of 3% by weight or more based on the total weight of the ink composition. An ink composition,

式（Ａ−１）及び式（Ａ−２）中、Ｒ¹は水素原子又はメチル基を表し、Ｒ²及びＲ³はそれぞれ独立にメチレン基又はエチレン基を表し、Ｒ⁴は水素原子又は炭素原子数１〜５のアルキル基を表し、Ｒ⁵及びＲ⁶はそれぞれ独立に水素原子、炭素原子数１〜５のアルキル基を表し、Ｒ⁵及びＲ⁶は互いに結合して環を形成してもよく、Ｌ¹は二価の連結基を表す、
＜２＞前記（Ｄ）重合開始剤がラジカル重合開始剤を含む、前記＜１＞に記載のインク組成物、
＜３＞前記（Ｄ）重合開始剤が芳香族ケトン類及び／又はアシルホスフィン化合物である、前記＜１＞又は＜２＞に記載のインク組成物、
＜４＞（Ｅ）着色剤を含有する、前記＜１＞〜＜３＞いずれか１つに記載のインク組成物、
＜５＞前記（Ａ）式（Ａ−１）及び／又は式（Ａ−２）で表される化合物が、アクリル酸（３−エチル−３−オキセタン−３−イル）メチル、４−アクリロイルオキシメチル−２−メチル−２−エチル−１，３−ジオキソラン、４−アクリロイルオキシメチル−２−メチル−２−イソブチル−１，３−ジオキソラン及び４−アクリロイルオキシメチル−２−シクロヘキシル−１，３−ジオキソランよりなる群から選ばれた少なくとも１つである、前記＜１＞〜＜４＞いずれか１つに記載のインク組成物、
＜６＞前記（Ｂ）脂環式骨格を有するエチレン性不飽和化合物が式（Ｂ−Ｉ）又は式（Ｂ−ＩＩ）で表される化合物である、前記＜１＞〜＜５＞いずれか１つに記載のインク組成物、

In Formula (A-1) and Formula (A-2), R ¹ represents a hydrogen atom or a methyl group, R ² and R ³ each independently represent a methylene group or an ethylene group, and R ⁴ represents a hydrogen atom or a carbon group. Represents an alkyl group having 1 to 5 atoms, R ⁵ and R ⁶ each independently represent a hydrogen atom and an alkyl group having 1 to 5 carbon atoms, and R ⁵ and R ⁶ are bonded to each other to form a ring; L ¹ represents a divalent linking group,
<2> The ink composition according to <1>, wherein the (D) polymerization initiator includes a radical polymerization initiator,
<3> The ink composition according to <1> or <2>, wherein the (D) polymerization initiator is an aromatic ketone and / or an acylphosphine compound.
<4> (E) The ink composition according to any one of <1> to <3>, which contains a colorant;
<5> (A) The compound represented by the formula (A-1) and / or the formula (A-2) is acrylic acid (3-ethyl-3-oxetan-3-yl) methyl, 4-acryloyloxy Methyl-2-methyl-2-ethyl-1,3-dioxolane, 4-acryloyloxymethyl-2-methyl-2-isobutyl-1,3-dioxolane and 4-acryloyloxymethyl-2-cyclohexyl-1,3- The ink composition according to any one of <1> to <4>, which is at least one selected from the group consisting of dioxolanes;
<6> Any of the above <1> to <5>, wherein the ethylenically unsaturated compound (B) having an alicyclic skeleton is a compound represented by the formula (BI) or the formula (B-II) The ink composition according to one;

式（Ｂ−Ｉ）及び式（Ｂ−ＩＩ）中、Ｒ¹は水素原子又はメチル基を表し、Ｘ¹は二価の連結基を表し、ｋは１〜６の整数を表し、ｑ個あるＲ²及びｒ個あるＲ³はそれぞれ独立に置換基を表し、ｑは０〜５の整数を表し、ｒは０〜５の整数を表し、式（Ｂ−ＩＩ）で表される化合物はＹ¹で表される環状炭化水素構造を有していてもよい、
＜７＞前記（Ｂ）脂環式骨格を有するエチレン性不飽和化合物が、ジシクロペンテニルオキシエチル（メタ）アクリレート、ジシクロペンテニル（メタ）アクリレート及びイソボルニル（メタ）アクリレートよりなる群から選ばれた少なくとも１つの化合物である、前記＜１＞〜＜６＞いずれか１つに記載のインク組成物、
＜８＞前記（Ｃ）その他の重合性化合物として非環状多官能エチレン性不飽和化合物を含む、前記＜１＞〜＜７＞いずれか１つに記載のインク組成物、
＜９＞（ａ¹）被記録媒体上に、前記＜１＞〜＜８＞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、前記インク組成物を硬化する工程、を含むことを特徴とするインクジェット記録方法、
＜１０＞前記＜９＞に記載のインクジェット記録方法によって記録されたことを特徴とする印刷物。

In formulas (BI) and (B-II), R ¹ represents a hydrogen atom or a methyl group, X ¹ represents a divalent linking group, k represents an integer of 1 to 6, and q R ² and r R ³ each independently represent a substituent, q represents an integer of 0 to 5, r represents an integer of 0 to 5, and the compound represented by the formula (B-II) is Y May have a cyclic hydrocarbon structure represented by ¹ ,
<7> The ethylenically unsaturated compound (B) having an alicyclic skeleton was selected from the group consisting of dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate and isobornyl (meth) acrylate. The ink composition according to any one of <1> to <6>, which is at least one compound;
<8> The ink composition according to any one of <1> to <7>, including an acyclic polyfunctional ethylenically unsaturated compound as the other polymerizable compound (C).
<9> (a ¹ ) A step of ejecting the ink composition according to any one of <1> to <8> on a recording medium; and (b ¹ ) active on the ejected ink composition. Irradiating radiation to cure the ink composition, and an ink jet recording method,
<10> A printed matter recorded by the inkjet recording method according to <9>.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an ink composition that provides a cured film that is excellent in curability and safety, and has excellent adhesion and flexibility, an ink jet recording method that uses the ink composition, and a printed matter. .

I. Ink composition The ink composition of the present invention comprises (A) a compound represented by formula (A-1) and / or formula (A-2), (B) an ethylenically unsaturated compound having an alicyclic skeleton, (C) Other polymerizable compounds and (D) a polymerization initiator, and the compounds represented by the formulas (A-1) and (A-2) are 3% by weight of the total weight of the ink composition. It contains above.

式（Ａ−１）及び式（Ａ−２）中、Ｒ¹は水素原子又はメチル基を表し、Ｒ²及びＲ³はそれぞれ独立にメチレン基又はエチレン基を表し、Ｒ⁴は水素原子又は炭素原子数１〜５のアルキル基を表し、Ｒ⁵及びＲ⁶はそれぞれ独立に水素原子、炭素原子数１〜５のアルキル基を表し、Ｒ⁵及びＲ⁶は互いに結合して環を形成してもよく、Ｌ¹は二価の連結基を表す。
なお、本明細書において、数値範囲を表す「Ｘ〜Ｙ」等の表記は、「Ｘ以上Ｙ以下」と同義であり、数値範囲の両端の数値を含むものとする。また、前記「（Ａ）」等を「成分（Ａ）」等ともいう。以下、本発明のインク組成物について詳細に説明する。

In Formula (A-1) and Formula (A-2), R ¹ represents a hydrogen atom or a methyl group, R ² and R ³ each independently represent a methylene group or an ethylene group, and R ⁴ represents a hydrogen atom or a carbon group. Represents an alkyl group having 1 to 5 atoms, R ⁵ and R ⁶ each independently represent a hydrogen atom and an alkyl group having 1 to 5 carbon atoms, and R ⁵ and R ⁶ are bonded to each other to form a ring; In addition, L ¹ represents a divalent linking group.
In this specification, the notation such as “X to Y” representing a numerical range is synonymous with “X or more and Y or less”, and includes numerical values at both ends of the numerical range. The “(A)” and the like are also referred to as “component (A)” and the like. Hereinafter, the ink composition of the present invention will be described in detail.

(A) Compound represented by formula (A-1) and / or formula (A-2) In the ink composition of the present invention, the component (A) is represented by formula (A-1) and / or formula (A-2). The compound (A) is contained in an amount of 3% by weight or more based on the total weight of the ink composition.
First, the compound represented by Formula (A-1) will be described.

式（Ａ−１）において、Ｒ¹は水素原子又はメチル基を表す。
Ｒ²及びＲ³はそれぞれ独立にメチレン基又はエチレン基を表し、Ｒ²及びＲ³のいずれか１つがメチレン基であることが好ましく、反応性の観点から、Ｒ²及びＲ³のいずれもメチレン基であるオキセタン環を形成することがより好ましい。
Ｒ⁴は水素原子又は炭素原子数１〜５のアルキル基を表す。
Ｌ¹は二価の連結基を表し、エーテル基（−Ｏ−）、エステル基（−Ｃ（Ｏ）Ｏ−又は−ＯＣ（Ｏ）−）、アミド基（−Ｃ（Ｏ）ＮＲ’−又は−ＮＲ’Ｃ（Ｏ）−）、カルボニル基（−Ｃ（Ｏ）−）、窒素原子（−ＮＲ’−）、置換基を有していてもよい炭素原子数１〜５のアルキレン基、又は、これらを２以上組み合わせた二価の基であることが好ましい。

In formula (A-1), R ¹ represents a hydrogen atom or a methyl group.
R ² and R ³ each independently represent a methylene group or an ethylene group, preferably any one of R ² and R ³ is a methylene group, from the viewpoint of reactivity, none of R ² and R ³ methylene It is more preferable to form an oxetane ring as a group.
R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
L ¹ 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′— or -NR'C (O)-), a carbonyl group (-C (O)-), a nitrogen atom (-NR'-), an optionally substituted alkylene group having 1 to 5 carbon atoms, or The divalent group is a combination of two or more of these.

  The compound represented by the formula (A-1) is preferably an oxetane (meth) acrylate compound represented by the formula (A-1-1).

式（Ａ−１−１）中、Ｒ¹は水素原子又はメチル基を表し、Ｌ¹は、Ｒ¹⁰又は−Ｒ¹⁰−Ｏ−Ｒ¹²−を表し、Ｒ¹⁰及びＲ¹²は炭素原子数１〜５のアルキレン基を表し、Ｒ⁴は炭素原子数１〜５のアルキル基を表す。

In formula (A-1-1), R ¹ represents a hydrogen atom or a methyl group, L ¹ represents R ¹⁰ or —R ¹⁰ —O—R ¹² —, and R ¹⁰ and R ¹² represent 1 carbon atom. Represents an alkylene group having ˜5, and R ⁴ represents an alkyl group having 1 to 5 carbon atoms.

R ¹ is preferably a hydrogen atom, L ¹ is preferably an alkylene group having 1 to 3 carbon atoms, and R ⁴ is preferably an alkyl group having 1 to 3 carbon atoms.
In the present invention, among oxetane (meth) acrylate compounds represented by the formula (A-1-1), acrylate compounds are preferable, and acrylic acid (3-ethyl-3-oxetane-3-yl) methyl is particularly preferable. .

  Next, the compound represented by Formula (A-2) will be described.

式（Ａ−２）中、Ｒ¹は水素原子又はメチル基を表す。
Ｒ⁵及びＲ⁶はそれぞれ独立に水素原子、炭素原子数１〜５のアルキル基を表し、Ｒ⁵及びＲ⁶は互いに結合して環を形成してもよい。
Ｌ¹は二価の連結基を表し、エーテル基（−Ｏ−）、エステル基（−Ｃ（Ｏ）Ｏ−又は−ＯＣ（Ｏ）−）、アミド基（−Ｃ（Ｏ）ＮＲ’−又は−ＮＲ’Ｃ（Ｏ）−）、カルボニル基（−Ｃ（Ｏ）−）、窒素原子（−ＮＲ’−）、置換基を有していてもよい炭素原子数１〜５のアルキレン基、又は、これらを２以上組み合わせた二価の基であることが好ましい。本発明においては、Ｌ¹は炭素原子数１〜５のアルキレン基であることがより好ましく、メチレン基であることがさらに好ましい。
さらに、式（Ａ−２）で表される化合物は式（Ａ−２−１）で表される化合物であることが好ましい。

In formula (A-2), R ¹ represents a hydrogen atom or a methyl group.
R ⁵ and R ⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ⁵ and R ⁶ may be bonded to each other to form a ring.
L ¹ 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′— or -NR'C (O)-), a carbonyl group (-C (O)-), a nitrogen atom (-NR'-), an optionally substituted alkylene group having 1 to 5 carbon atoms, or The divalent group is a combination of two or more of these. In the present invention, L ¹ is more preferably an alkylene group having 1 to 5 carbon atoms, and more preferably a methylene group.
Furthermore, the compound represented by the formula (A-2) is preferably a compound represented by the formula (A-2-1).

In formula (A-2-1), R ¹ represents a hydrogen atom or a methyl group.
R ⁵ and R ⁶ are preferably a methyl group, an ethyl group, or a t-butyl group. When forming a ring, R ⁵ and R ⁶ have 3 to 8 ring members together with the carbon atom to which R ⁵ and R ⁶ are bonded. A cycloalkyl group is preferably formed, and a cyclohexyl structure is more preferably formed.

  Specific examples of the compound represented by the formula (A-2) include 4- (meth) acryloyloxymethyl-2-methyl-2-methyl-1,3-dioxolane, 4- (meth) acryloyloxymethyl-2 -Methyl-2-ethyl-1,3-dioxolane, 4- (meth) acryloyloxymethyl-2-methyl-2-isobutyl-1,3-dioxolane, 4- (meth) acryloyloxymethyl-2-cyclohexyl-1 , 3-dioxolane, 4- (meth) acryloyloxymethyl-2-methyl-2-acetonyl-1,3-dioxolane, 4- (meth) acryloyloxymethyl-2-oxo-1,3-dioxolane, 2- ( (Meth) acryloyloxyethyl-2-oxo-1,3-dioxolan-4-ylmethyl carbonate, 2-oxo-1,3-dio Solan-4-ylmethyl-3- (meth) acryloyloxypropionate, N- (meth) acryloyloxyethyl oxazolidone, N- (meth) acryloyloxyethyl pyrrolidone, 2- (meth) acryloyloxyethyl oxazoline, N- ( And (meth) acryloyloxyethyl succinimide.

In the present invention, the compound represented by the formula (A) and / or the formula (A-2) is preferably a compound having an acryloyl group in which R ¹ is a hydrogen atom. Acid (3-ethyl-3-oxetan-3-yl) methyl, 4-acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane, 4-acryloyloxymethyl-2-methyl-2-isobutyl- More preferably, it is at least one selected from the group consisting of 1,3-dioxolane and 4-acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane.

The ink composition of the present invention contains 3% by weight or more of the compound represented by the formula (A-1) and the formula (A-2) based on the total weight of the ink composition. When the ink composition contains only the compound represented by the formula (A-1) (or the formula (A-2)), it is represented by “the formula (A-1) and the formula (A-2)”. The content of “compound” is equal to the content of the compound represented by formula (A-1) (or formula (A-2)). When the content of the compound represented by Formula (A-1) or Formula (A-2) is less than 3% by weight, the adhesion and curability are poor.
10-60 weight% is preferable, as for content of the said component (A), 15-50 weight% is more preferable, and 20-45 weight% is further more preferable. It is excellent in adhesiveness and sclerosis | hardenability in it being in the range of said numerical value.

(B) Ethylenically unsaturated compound having an alicyclic skeleton The ink composition of the present invention contains an ethylenically unsaturated compound having an alicyclic skeleton as the component (B). Component (B) is preferably a compound having at least one ethylenically unsaturated bond. As the alicyclic skeleton, a cycloalkane skeleton, an adamantane skeleton and a norbornane skeleton are preferable, and an adamantane skeleton and a norbornane skeleton are more preferable.
Component (B) is preferably a monomer represented by Formula (BI) or Formula (B-II).

In formulas (BI) and (B-II), R ¹ represents a hydrogen atom or a methyl group, X ¹ represents a divalent linking group, k represents an integer of 1 to 6, and q R ² and r R ³ each independently represent a substituent, q represents an integer of 0 to 5, r represents an integer of 0 to 5, and the compound represented by the formula (B-II) is Y It may have a cyclic hydrocarbon structure represented by ¹ .
R ¹ in formula (BI) or formula (B-II) represents a hydrogen atom or a methyl group, and k R ^{1 s} may be the same or different.

X ¹ in Formula (BI) or Formula (B-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′— or —NR′C (O) —), a carbonyl group (—C (O) —), a nitrogen atom (—NR′—), and a substituent. It is preferably an alkylene group having 1 to 15 carbon atoms, or a divalent group in which two or more thereof are combined. R ′ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. The k X ^{1 s} may be the same or different.

Further, the end that binds to the vinyl group of X ¹ in the formula (B-I) or Formula (B-II) is preferably an ester group or in which the carbonyl carbon and a vinyl group X ¹ binds is an amide group In this case, the other part of X ¹ bonded to the adamantane skeleton or the norbornane skeleton may be a single bond or an arbitrary part 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 (BI) or formula (B-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. In addition, “on each alicyclic hydrocarbon structure” refers to an adamantane structure in the formula (BI), a norbornane structure in the formula (B-II), and a cyclic hydrocarbon structure including Y ¹ .
Further, from the viewpoint of improving the affinity with the colorant, the end bonded to the alicyclic hydrocarbon structure of X ¹ in the formula (BI) or (B-II) is an oxygen atom. Is more preferably an etheric oxygen atom, and X ¹ in formula (BI) or formula (B-II) is —C (O) O (CH ₂ CH ₂ O) _p — (p is 0). It represents an integer of ˜2).

R ² and R ³ in formula (BI) and formula (B-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 hydroxy group, substituted or unsubstituted An amino group, a thiol group, a siloxane group, a hydrocarbon group or a heterocyclic group having 30 or less total carbon atoms which may have a substituent, or an oxy group (= O) as a divalent substituent Preferably there is.
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.

Y ¹ in the formula (B-II) represents a cyclic hydrocarbon structure, and both ends thereof may be substituted at any position of the norbornane skeleton, and may be a monocyclic structure or a polycyclic structure. In addition, the cyclic hydrocarbon structure may include a carbonyl bond (—C (O) —) and / or an ester bond (—C (O) O—) in addition to the hydrocarbon bond.
Further, one carbon atom in the adamantane skeleton in formula (BI) may be substituted with a carbonyl bond (—C (O) —) and / or an ester bond (—C (O) O—). One carbon atom in the norbornane skeleton in B-II) may be substituted with an ether bond (—O—) and / or an ester bond (—C (O) O—).

When the monomer represented by the formula (B-II) has a cyclic hydrocarbon structure represented by Y ¹ , the monomer represented by the formula (B-III), the formula (B-IV) or the formula (B-V) It is preferable that it is a monomer represented by these.

Formula ^{(B-III), R 1} , X 1 and k in the formula (B-IV) or Formula (B-V) is, R ¹ in the formula (B-I) or Formula (B-II), X ¹ and It is synonymous with k, and its preferable range is also the same.
In formula (B-III), formula (B-IV) and formula (B-V), R ⁴ , R ⁵ and R ⁶ each independently represent a substituent, k represents an integer of 1 to 6, , T and u each independently represents an integer of 0 to 5, and s R ⁴ , t R ⁵ and u R ⁶ are the same or different. May be.

The vinyl moiety containing R ¹ and X ¹ in formula (B-III), formula (B-IV) or formula (B-V) can be represented by formula (B-III), formula (B-IV) or formula (B- The bond can be made at any position on each alicyclic hydrocarbon structure shown below in V).

R ⁴ , R ⁵ and R ⁶ in formula (B-III), formula (B-IV) or formula (B-V) each independently represent a substituent, and formula (B-III), formula (B-IV) ) Or the formula (BV) in any position on each of the above alicyclic hydrocarbon structures. The substituents in R ⁴ , R ⁵ and R ^{6 have the same} meanings as the substituents in R ² and R ³ in formula (BI) or formula (B-II), and the preferred ranges are also the same.

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

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

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

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

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

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

  Among the components (B), the ethylenically unsaturated compound having a cycloalkane skeleton is preferably a compound having a cycloalkyl group having 3 to 12 carbon atoms. Of these, (meth) acrylate and (meth) acrylamide having a cycloalkyl group are preferred. Specifically, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, cyclooctyl (meth) acrylate, cyclodecyl. (Meth) acrylate, trimethylcyclohexyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, N-cyclohexyl (meth) acrylamide and the like can be exemplified, and among them, cyclohexyl (meth) acrylate is preferable.

  In the present invention, the ethylenically unsaturated compound having an alicyclic skeleton of component (B) is preferably a (meth) acrylate having an alicyclic skeleton, and represented by formula (BI) or formula (B- (Meth) acrylate corresponding to the compound represented by II) is more preferred. Among them, monofunctional (meth) acrylate is preferable, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and isobornyl (meth) acrylate are more preferable, dicyclopentenyloxyethyl (meth) acrylate and / or More preferred is dicyclopentenyl (meth) acrylate.

  In the present invention, when the ink composition does not contain the component (B), the curability is inferior. The content of the component (B) is preferably 5 to 60% by weight, more preferably 8 to 50% by weight, more preferably 10 to 40% by weight based on 100% by weight of the solid content excluding the solvent in the ink composition. % Is more preferable. When it is within the above numerical range, the curability is excellent.

  Moreover, in this invention, it is preferable that the ratio of (A) and (B) is 10: 90-90: 10 by weight ratio, It is more preferable that it is 25: 75-80: 20, 35 : 65 to 70:30 is more preferable. It is excellent in adhesiveness and sclerosis | hardenability in it being in the range of said numerical value.

(C) Other polymerizable compounds The ink composition of the present invention contains (C) other polymerizable compounds excluding component (A) and component (B). (C) Other polymerizable compounds can be appropriately selected according to the intended ink cured film characteristics.
In the present invention, (C) the other polymerizable compound is preferably an ethylenically unsaturated compound, more preferably an acyclic ethylenically unsaturated compound having no cyclic structure, and a polyfunctional ethylenically unsaturated compound. Compounds are more preferred. That is, as the component (C), an acyclic polyfunctional ethylenically unsaturated compound is preferable. Furthermore, as the acyclic polyfunctional ethylenically unsaturated compound, an acyclic polyfunctional (meth) acrylate compound and an acyclic polyfunctional vinyl ether compound are preferable. By containing an acyclic polyfunctional ethylenically unsaturated compound, an ink composition having excellent curability and an image having high cured film strength can be obtained.

  Specific examples of the acyclic polyfunctional (meth) acrylate compound include neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tri Ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra ( (Meth) acrylate, tetramethylolmethane tetra (meth) acrylate, tetramethylolmethane tri (meth) acrylate, modified glycerin tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol di (meth) acrylate, Caprolactone-modified dipentaerythritol hexa (meth) acrylate, (poly) tetramethylene glycol di (meth) Acrylate, EO modified pentaerythritol tri (meth) acrylate, PO modified pentaerythritol tri (meth) acrylate, EO modified pentaerythritol tetra (meth) acrylate, PO modified pentaerythritol tetra (meth) acrylate, EO modified dipentaerythritol tetra (meth) ) Acrylate, PO-modified dipentaerythritol tetra (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO-modified tetramethylolmethane tetra (meth) acrylate and PO-modified tetra Methylolmethane tetra (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, pentaerythritol Examples thereof include tri (meth) acrylate tolylene diisocyanate urethane prepolymer, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate urethane prepolymer, and the like. Among them, those having 2 to 3 functional groups are preferable, and dipropylene glycol di ( (Meth) acrylate, trimethylolpropane tri (meth) acrylate, and propoxylated neopentyl glycol di (meth) acrylate are preferred.

  Examples of the acyclic polyfunctional vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, Examples thereof include di- or trivinyl ether compounds such as methylolpropane trivinyl ether, among which triethylene glycol divinyl ether is preferable.

(C) The proportion of the non-cyclic polyfunctional ethylenically unsaturated compound in other polymerizable compounds is preferably 50 to 100% by weight, more preferably 70 to 100% by weight, and even more preferably 100% by weight.
Moreover, 50-100 weight% is preferable and, as for the ratio for which acyclic polyfunctional (meth) acrylate accounts in (C) other polymeric compounds, 70-100 weight% is more preferable.
Further, the proportion of (C) other polymerizable compound in the entire ink composition is preferably 4 to 40% by weight, more preferably 10 to 30% by weight, and more preferably 15 to 25% by weight. It is preferable for it to be within the above numerical value range because an ink composition having excellent curability and an image having a high cured film strength can be obtained.

(D) Polymerization initiator The ink composition of the present invention contains a polymerization initiator as the component (D). As the component (D), a radical polymerization initiator is preferable. The radical polymerization initiator may be used alone or in combination of two or more. A radical polymerization initiator and a cationic polymerization initiator may be used in combination.
The radical polymerization initiator 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.

  Examples of the radical polymerization initiator include (a) aromatic ketones, (b) acylphosphine compounds, (c) aromatic onium salt compounds, (d) organic peroxides, (e) thio compounds, and (f) hexaary. Rubiimidazole compound, (g) ketoxime ester compound, (h) borate compound, (i) azinium compound, (j) metallocene compound, (k) active ester compound, (l) compound having carbon halogen bond and (m) Examples thereof include alkylamine compounds. You may use the compound of said (a)-(m) individually or in combination.

  (A) As a preferable example of aromatic ketones, “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” P. FOUASSIER J.M. F. RABEK (1993), pp. Examples thereof include a compound having a benzophenone skeleton described in 77 to 117 (benzophenone compound) or a compound having a thioxanthone skeleton (thioxanthone compound). Examples of preferable (a) aromatic ketones and (b) acylphosphine compounds 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, and JP-B-60-26483 Dialkoxybenzophenone, benzoin ethers described in JP-B-60-26403, JP-A-62-81345, JP-B-1-34242, US Pat. No. 4,318,791, European Patent 0284561A1 Α-Aminobenzophenones, JP-A-2-211452 P-di (dimethylaminobenzoyl) benzene described in JP-A-61-194062, thio-substituted aromatic ketone described in JP-A-61-194062, acylphosphine sulfide described in JP-B-2-9597, described in JP-B-2-9596 Acyl phosphines, thioxanthones described in JP-B-63-61950, and coumarins described in JP-B-59-42864.

Examples of the benzophenone compound include benzophenone, 4-phenylbenzophenone, isophthalophenone, 4-benzoyl-4′-methylphenyl sulfide and the like. As the benzophenone compound, it is also preferable to use a diaminobenzophenone compound. An example of the diaminobenzophenone compound is p, p′-tetramethyldiaminobenzophenone.
Examples of the thioxanthone compound include 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone and the like.

In the present invention, (a) the aromatic ketone is preferably an α-hydroxyketone, such as 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane- 1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone and the like.
Among these, as (a) aromatic ketones, a 1-hydroxycyclohexyl phenyl ketone compound is particularly preferable. In the present invention, the 1-hydroxycyclohexyl phenyl ketone compound means a compound in which 1-hydroxycyclohexyl phenyl ketone and 1-hydroxycyclohexyl phenyl ketone are substituted with an arbitrary substituent. The substituent can be arbitrarily selected as long as it can exhibit the ability as a radical polymerization initiator, and specific examples thereof include alkyl groups (eg, methyl group, ethyl group, propyl group, butyl group). it can.

In the present invention, the (b) acylphosphine compound is preferably an acylphosphine oxide compound.
Examples of the acylphosphine oxide compound include those having the structural formula of formula (7) or formula (8) in the structure of the compound.

  In particular, as the acylphosphine oxide compound, those having a chemical structure of the formula (9) or the formula (10) are particularly preferable.

式（９）中、Ｒ₆、Ｒ₇、Ｒ₈はメチル基又はエチル基を置換基として有していてもよい芳香族炭化水素基を表す。

In formula (9), R ₆ , R ₇ and R ₈ represent an aromatic hydrocarbon group which may have a methyl group or an ethyl group as a substituent.

式（１０）中、Ｒ₉、Ｒ₁₀、Ｒ₁₁はメチル基又はエチル基を置換基として有していてもよい芳香族炭化水素基を表す。

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

  As the acylphosphine oxide compound, a monoacylphosphine oxide compound, a bisacylphosphine oxide compound, or the like can be used. As the monoacylphosphine oxide compound, a known monoacylphosphine oxide compound can be used. Examples thereof include monoacylphosphine oxide compounds described in Japanese Patent Publication No. 60-8047 and Japanese Patent Publication No. 63-40799. Specific examples include isobutyryl-methylphosphinic acid methyl ester, isobutyryl-phenylphosphinic acid methyl ester, pivaloyl-phenylphosphinic acid methyl ester, 2-ethylhexanoyl-phenylphosphinic acid methyl ester, pivaloyl-phenylphosphinic acid isopropyl ester, p. -Toluyl-phenylphosphinic acid methyl ester, o-toluyl-phenylphosphinic acid methyl ester, 2,4-dimethylbenzoyl-phenylphosphinic acid methyl ester, p-tert-butylbenzoyl-phenylphosphinic acid isopropyl ester, acryloyl-phenylphosphinic acid Methyl ester, isobutyryl-diphenylphosphine oxide, 2-ethylhexanoyl-diphenylphosphine oxide, o-to Yl-diphenylphosphine oxide, p-tertiarybutylbenzoyl-diphenylphosphine oxide, 3-pyridylcarbonyl-diphenylphosphine oxide, acryloyl-diphenylphosphine oxide, benzoyl-diphenylphosphine oxide, pivaloyl-phenylphosphinic acid vinyl ester, adipoyl-bis- Diphenylphosphine oxide, pivaloyl-diphenylphosphine oxide, p-toluyl-diphenylphosphine oxide, 4- (tertiarybutyl) -benzoyl-diphenylphosphine oxide, terephthaloyl-bis-diphenylphosphine oxide, 2-methylbenzoyl-diphenylphosphine oxide, versatoyl -Diphenylphosphine oxide, 2-methyl-2-ethyl Examples include ruhexanoyl-diphenylphosphine oxide, 1-methyl-cyclohexanoyl-diphenylphosphine oxide, pivaloyl-phenylphosphinic acid methyl ester, and pivaloyl-phenylphosphinic acid isopropyl ester.

  A known bisacylphosphine oxide compound can be used as the bisacylphosphine oxide compound. Examples thereof include bisacylphosphine oxide compounds described in JP-A-3-101686, JP-A-5-345790, and JP-A-6-298818. Specific examples include bis (2,6-dichlorobenzoyl) -phenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichlorobenzoyl). -4-ethoxyphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2-naphthylphosphine oxide, bis (2,6-di Chlorobenzoyl) -1-naphthylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-chlorophenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,4-dimethoxyphenylphosphine oxide, bis ( 2,6-dichlorobenzoyl) -decylphosphine oxide, bis (2 , 6-Dichlorobenzoyl) -4-octylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,5-dimethylphenylphosphine oxide Bis (2,6-dichloro-3,4,5-trimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichloro-3,4,5-trimethoxybenzoyl) -4- Ethoxyphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-ethoxyphenylphosphine oxide, bis (2-methyl-1 -Naphthoyl) -2-naphthylphosphine oxide, bis (2-methyl- 1-naphthoyl) -4-propylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methoxy-1-naphthoyl) -4-engineered phenylphenylphosphine oxide Bis (2-chloro-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, and the like.

  Among these, in the present invention, as the acylphosphine oxide compound, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure 819: manufactured by Ciba Specialty Chemicals), bis (2,6-dimethoxy) Benzoyl) -2,4,4-trimethyl-pentylphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Darocur TPO: Ciba Specialty Chemicals, Lucirin TPO: BASF), etc. Is preferred.

  (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 No. 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 ′, Perester ester compounds such as 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone and di-t-butyldiperoxyisophthalate Thing is preferable.

  (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 ′ − Traphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 Examples include ', 5,5'-tetraphenylbiimidazole.

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

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

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

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

  Specific examples of the titanocene compound include di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, and di-cyclopentadienyl-Ti-bis-2,3. 4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti- Bis-2,4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4 -Difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti- -2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyridin-1-yl) phenyl) titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (methylsulfonamido) phenyl] titanium, bis (cyclopenta And dienyl) bis [2,6-difluoro-3- (N-butylbialoyl-amino) phenyl] titanium.

  (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.

  (M) Alkylene diamines include alkylene diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.), polyalkylenes (alkylene having 2 to 6 carbon atoms), polyamines (diethylene triamine, triethylene tetramine, pentaethylene hexamine, iminobispropyl). Amine, bis (hexamethylene) triamine, etc.), alkyl or hydroxyalkylamine compounds (alkyl (C1-3) aminopropylamine, aminoethylethanolamine, methyliminobispropylamine, etc.), N-aminoethylpiperazine, 1,3-diaminocyclohexane, ifolonediamine, hydrogenated methylenedianiline, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] un Cans and the like, N, N- dimethylcyclohexylamine, triethylamine, N- methylmorpholine, N- ethylmorpholine, triethylenediamine, 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 present invention, among the compounds (a) to (m), (a) aromatic ketones and / or (b) acylphosphine compounds are preferable, and (a) aromatic ketones and (b) An embodiment in which an acylphosphine compound is used in combination is more preferred.

  Preferred examples of (a) aromatic ketones include 1-hydroxy-cyclohexyl-phenyl-ketone and isopropylthioxanthone. Examples of (b) acylphosphine compounds include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide.

(D) The total amount of polymerization initiator used is preferably 0.01 to 35% by weight, more preferably 0.5 to 20% by weight, based on the total amount of polymerizable compounds including (A) to (C). 1.0 to 15% by weight is more preferable. When it is within the above numerical range, it is excellent in curability and a uniform cured film can be obtained. When the total amount of the ink composition is 100% by weight, the content of the (D) polymerization initiator is preferably 1 to 20% by weight, and more preferably 5 to 15% by weight.
When adding a sensitizer to the ink composition, the total amount of radical polymerization initiator used is preferably a weight ratio of radical polymerization initiator: sensitizer to the sensitizer, preferably 200: 1 to 1. The range is 1: 200, more preferably 50: 1 to 1:50, and still more preferably 20: 1 to 1: 5.

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

  Colorants that can be used in the present invention include pigments and oil-soluble dyes. The pigment is not particularly limited, and for example, organic or inorganic pigments described in the color index can be used. Preferably, red or magenta pigments, blue or cyan pigments described in JP-A-2008-019408 are used. A pigment such as a pigment, a green pigment, a yellow pigment, a black pigment, or a white pigment can be used. As the oil-soluble dye, oil-soluble dyes described in the same publication can be used. The oil-soluble dye that can be used in the present invention means a dye that is substantially insoluble in water. Specifically, the solubility in water at 25 ° C. (the weight of the dye that can be dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. These colorants may be used by appropriately selecting one type or two or more types according to the purpose of use of the ink composition.

  It is preferable that the colorant that can be used in the present invention is appropriately dispersed in the ink composition after being added to the ink composition of the present invention. For dispersing the colorant, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, or a paint shaker can be used.

  In the preparation of the ink composition of the present invention, the colorant may be blended by direct addition with each component. However, in order to improve the dispersibility, the colorant is previously added to a dispersion medium such as a solvent or a polymerizable compound used in the present invention. It can also be added after being added, uniformly dispersed or dissolved. In the present invention, in order to avoid the problem of deterioration of solvent resistance when the solvent remains in the cured image and the problem of VOC (Volatile Organic Compound) of the remaining solvent, the colorant contains a polymerizable compound. It is preferable to add and mix in advance in such a dispersion medium. In consideration of only dispersibility, it is preferable to select a monomer having the lowest viscosity as the polymerizable compound used for the addition of the colorant.

In the present invention, when using a colorant such as a pigment that remains solid, the average particle diameter of the colorant particles is preferably 0.005 to 0.5 μm, more preferably 0.01 to 0.45 μm. Furthermore, it is preferable to set the colorant, the dispersant, the dispersion medium, the dispersion conditions, and the filtration conditions so that the thickness is 0.015 to 0.4 μm. By controlling the particle size, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.
The content of the colorant in the ink composition of the present invention is selected depending on the color and purpose of use, but is preferably 0.01 to 30% by weight with respect to the weight of the whole ink composition.

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

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

<Polymerization inhibitor>
The ink composition of the present invention may contain a polymerization inhibitor in order to suppress undesired radical polymerization during storage. Polymerization inhibitors include phenolic hydroxyl group-containing compounds, quinones, N-oxide compounds, piperidine 1-oxyl free radical compounds, pyrrolidine 1-oxyl free radical compounds, N-nitrosophenylhydroxylamines, and And compounds selected from the group consisting of cationic dyes.

  Specific examples of the polymerization inhibitor include haloid quinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, resorcinol, catechol, t-butylcatechol, hydroquinone, benzoquinone, 4,4-thiobis (3-methyl). -6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2,6,6-tetramethylpiperidine and its derivatives, di-tert-butyl nitroxide, 2, 2,6,6-tetramethylpiperidine-N-oxide and its derivatives, such as piperidine 1-oxyl free radical, 2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-oxo-2,2, 6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy- , 2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-maleimido-2,2,6,6-tetra Methylpiperidine 1-oxyl free radical, 4-phosphonoxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 3-carboxy-2,2,5,5-tetramethylpyrrolidine 1-oxyl free radical, N-nitrosophenylhydroxylamine primary cerium salt, N-nitrosophenylhydroxylamine aluminum salt, crystal violet, methyl violet, ethyl violet, Victoria pure blue BOH and the like.

  The content of the polymerization inhibitor in the ink composition is preferably 0.0001 to 1% by weight, more preferably 0.001 to 0.5% by weight, and still more preferably 0.001 to 0.3% by weight. Within the above numerical range, polymerization during preparation of the ink composition can be suppressed, and clogging of the ink jet nozzle can be prevented.

  Furthermore, the ink composition of the present invention includes a sensitizer, a co-sensitizer (strong sensitizer), a cationic polymerizable compound, a cationic polymerization initiator, an ultraviolet absorber, described in JP-A-2008-207411. Antioxidants, anti-fading agents, conductive salts, solvents, polymer compounds, basic compounds and the like can be added.

(Ink properties)
In the present invention, the viscosity of the ink composition at 25 ° C. is preferably 40 mPa · s or less, more preferably 5 to 40 mPa · s, and more preferably 7 to 30 mPa · s in consideration of dischargeability. Is more preferable.
Moreover, it is preferable that the viscosity in discharge temperature (Preferably 25-80 degreeC, More preferably, 25-50 degreeC) is 3-20 mPa * s, and it is more preferable that it is 3-15 mPa * s. It is preferable that the composition ratio of the ink composition of the present invention is appropriately adjusted so that the viscosity is in the above range. By setting the viscosity at room temperature high, even when a porous recording medium is used, ink penetration into the recording medium can be avoided and uncured monomer can be reduced. Furthermore, it is preferable that ink bleeding at the time of ink droplet landing can be suppressed, and as a result, the image quality is improved.

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

II. Inkjet recording method and printed matter The ink composition of the invention is preferably 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.), and the ink composition ejected onto the recording medium is irradiated with actinic radiation. It is a method for forming an image by curing a composition.
In the inkjet recording method of the present invention, (a ¹ ) a step of ejecting the ink composition of the present invention onto a recording medium, and (b ¹ ) irradiating the ejected ink composition with actinic radiation, And a step of curing the ink composition.
The printed matter of the present invention is recorded by the ink jet recording method of the present invention. Hereinafter, the inkjet recording method and printed matter of the present invention will be described.

In the step (a ¹ ) in the ink jet recording method, an ink jet recording apparatus described in detail below can be used.
There is no restriction | limiting in particular as an inkjet recording device used for the inkjet recording method of this invention, The well-known inkjet recording device which can achieve the target resolution can be selected arbitrarily and can be used. That is, any known ink jet recording apparatus including a commercially available product can discharge the ink composition onto the recording medium in the step (a ¹ ) of the ink jet recording method of the present invention.

Examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and an actinic radiation source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head preferably has a multi-size dot of 1 to 100 pl, more preferably 8 to 30 pl, preferably 320 × 320 to 4,000 × 4,000 dpi, more preferably 400 × 400 to 1,600 ×. It can be driven so that it can discharge at a resolution of 1,600 dpi, more preferably 720 × 720 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

  As described above, 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 heat energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

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

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

Next, (b ¹ ) a step of curing the ink composition by irradiating the discharged ink composition with active radiation will be described.
The ink composition ejected on the recording medium is cured by irradiation with actinic radiation. This is because (D) the polymerization initiator contained in the ink composition of the present invention is decomposed by irradiation with actinic radiation to generate initiating species such as radicals, acids and bases, and the function of the initiating species is radically polymerizable. This is because the polymerization reaction of the compound 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 sensitizer, it is preferable that it is 200-600 nm, for example, it is more preferable that it is 300-450 nm, and it is further more preferable that it is 350-420 nm.

In addition, the polymerization initiation system of the ink composition of the present invention has sufficient sensitivity even with a low output actinic radiation. Therefore, it is appropriate 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. The actinic radiation source particularly preferred in the present invention is a UV-LED, particularly preferably a UV-LED having a peak wavelength at 350 to 420 nm.
Incidentally, it is preferable that maximum illumination intensity of the LED on a recording medium is 10 to 2,000 mW / cm ^2, more preferably 20 to 1,000 mW / cm ^2, particularly preferably 50 to 800 mW / cm ² .

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

  The material used for the recording medium is not particularly limited, and any material may be used. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, acrylic resin (poly (meth) acrylic ester resin) And (meth) acrylic acid ester copolymer), cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl chloride, High impact polystyrene, polyvinyl acetal, etc.), paper or plastic film on which the above-mentioned metal is laminated or deposited. These materials may be appropriately used after surface treatment. In the present invention, acrylic resin, polyvinyl chloride, polycarbonate and high impact polystyrene are preferable from the viewpoint of adhesion, and acrylic resin is particularly preferable.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on weight.
(Material)
The materials used in the examples and comparative examples are as shown below.
<Component (A)>
OXE-10 (acrylic acid (3-ethyl-3-oxetane-3-yl) methyl), MEDOL (4-acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane), MIBDOL ( 4-acryloyloxymethyl-2-methyl-2-isobutyl-1,3-dioxolane) and CHDOL (4-acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane) (manufactured by Osaka Organic Chemical Industry Co., Ltd.) Using.

<Component (B)>
FA-512A (dicyclopentenyloxyethyl acrylate, manufactured by Hitachi Chemical Co., Ltd.)
FA-511A (dicyclopentenyl acrylate, manufactured by Hitachi Chemical Co., Ltd.)
SR506 (isobornyl acrylate, manufactured by SARTOMER)
・ V # 155 (cyclohexyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)

<Ingredient (C)>
SR339 (2-phenoxyethyl acrylate, manufactured by SARTOMER)
SR285 (tetrafurfuryl acrylate, manufactured by SARTOMER)
SR508 (dipropylene glycol diacrylate, manufactured by SARTOMER)
SR351S (trimethylolpropane triacrylate, manufactured by SARTOMER)
・ RAPI-CURE DVE-3 (triethylene glycol divinyl ether, manufactured by ISP)
SR9003 (propoxylated (2) neopentyl glycol diacrylate (a compound obtained by diacrylated neopentyl glycol propylene oxide 2 mol adduct), manufactured by SARTOMER)
SR212 (1,3-butylene glycol diacrylate, manufactured by SARTOMER)
SR213 (1,4-butanediol diacrylate, manufactured by SARTOMER)

<Component (D)>
IRGACURE 184 (1-hydroxy-cyclohexyl-phenyl-ketone, manufactured by Ciba Specialty Chemicals)
IRGACURE 819 (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, manufactured by Ciba Specialty Chemicals)
・ Lucirin TPO (diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide, manufactured by BASF)
FIRSTCURE ITX (Isopropylthioxanthone, manufactured by Chem First)

<Ingredient (E)>
・ IRGALITE BLUE GLVO (Cyan Pigment, Ciba Specialty Chemicals)
・ NOVOPERM YELLOW H2G (yellow pigment, manufactured by Clariant)
・ CINQUASIA MAGENTA RT-335 D (Magenta pigment, manufactured by Ciba Specialty Chemicals)
・ TIPAQUE CR-60-2 (white pigment, manufactured by Ishihara Sangyo Co., Ltd.)

<Component (F)>
FIRSTCURE ST-1 (polymerization inhibitor, manufactured by Chem First)
DISPERBYK-168 (pigment dispersant, manufactured by BYK Chemie)
SOLPERSE 32000 (pigment dispersant, manufactured by Lubrizol)
SOLPERSE 36000 (pigment dispersant, manufactured by Lubrizol)
・ BYK-307 (silicone surfactant, manufactured by Shin-Etsu Chemical Co., Ltd.)

(Preparation of mill base)
Cyan, yellow, magenta, and white mill bases were mixed in the following composition and stirred for 10 minutes at 2,500 rpm using a mixer (Silverson L4R). Then, it put into bead mill disperser DISPERMAT LS (made by VMA), and disperse | distributed for 6 hours at 2500 rotation / min using the YTZ ball | bowl (made by Nikkato Co., Ltd.) with a diameter of 0.65 mm.

<Cyan mill base>
IRGALITETE BLUE GLVO 30 parts RAPI-CURE DVE-3 50 parts DISPERBYK-168 20 parts

<Yellow mill base>
NOVOPERM YELLOW H2G 30 parts RAPI-CURE DVE-3 42 parts DISPERBYK-168 28 parts

<Magenta mill base>
CINQUASIA MAGENTA RT-335 D 30 parts SOLPERSE 32000 11 parts SR9003 58 parts FIRSTCURE ST-1 1 part

<White mill base>
TIPAQUE CR-60-2 70 parts SR339 25 parts SOLSPERSE 36000 5 parts

Example 1
The following components were stirred at 2,500 rpm for 15 minutes using a mixer (Silverson L4R) to obtain a cyan ink composition 1.
OXE-10 34.0 parts FA-512A 30.0 parts SR508 14.3 parts SR351S 1.0 parts FIRSTCURE ST-1 0.1 parts IRGACURE 184 3.0 parts IRGACURE 819 1.0 part Lucirin TPO 5.5 parts FIRSTCURE ITX 1.0 part BYK-307 0.1 part Cyan Mill Base 10.0 part

(Evaluation of ink composition)
<Curing speed>
The ink composition 1 was applied to the surface of polyvinyl chloride (thickness 220 μm) as a recording medium using a K hand coater (bar No. 2) so as to have a wet film thickness of 12 μm. Next, inside the UV conveyor device CSOT (manufactured by GS Yuasa Lighting), which is equipped with an ozone-less metal halide lamp MAN125L and set to a conveyor speed of 8.7 m / min and an exposure intensity of 760 W / cm ² , until the coating surface is no longer sticky Repeated passage and radiation curing. The curing rate was evaluated according to the following criteria. The results are shown in Table 2.
A: Tack-free after one pass. The curing rate is extremely fast.
○: Tack-free after 2 passes. Cure speed is fast.
Δ: Tack-free after 3 passes. The curing rate is slightly slow.
X: It became tack-free when the number of passes was 4 or more. Cure speed is slow.

<Adhesion to recording medium>
The ink composition 1 was applied to the surface of an acrylic substrate as a recording medium using a K hand coater (bar No. 2) so as to have a wet film thickness of 12 μm. Next, inside the UV conveyor device CSOT (manufactured by GS Yuasa Lighting), which is equipped with an ozone-less metal halide lamp MAN125L and set to a conveyor speed of 8.7 m / min and an exposure intensity of 760 W / cm ² , until the coating surface is no longer sticky Repeated passage and radiation curing. The adhesion to the recording medium was evaluated according to the following criteria by ISO 2409 (cross cut method) using this cured coating film. The results are shown in Table 2.
0: The edge of the cut is completely smooth and there is no peeling to the eyes of any lattice.
1: Small peeling of the coating film at the intersection of cuts. The cross cut is not affected by more than 5%.
2: Peel along the edge of the cut of the coating and / or at the intersection. The cross-cut portion is affected by more than 5% but not more than 15%.
3: The coating film is partially or completely peeled along the edge of the cut, and / or various parts of the eye are partially or completely peeled off. The cross-cut part is affected by more than 15% but not more than 35%.
4: The coating film is partially or completely peeled along the edge of the cut, and / or some eyes are partially or completely peeled off. The cross-cut portion is affected by more than 35% but not more than 65%.

<Flexibility>
The ink composition 1 was applied to the surface of polyvinyl chloride (thickness 220 μm) as a recording medium using a K hand coater (bar No. 2) so as to have a wet film thickness of 12 μm. Next, the ozone-less metal halide lamp MAN125L is installed, and it is repeatedly passed through the UV conveyor device CSOT (manufactured by GS Yuasa Lighting) set at a conveyor speed of 8.7 m / min and an exposure intensity of 760 W / cm ² for radiation curing. It was. The evaluation of the flexibility was performed by reciprocating the same place of the cured coating film 5 times and bending it, and then evaluating the degree of cracks generated in the coating film according to the following criteria. The results are shown in Table 2.
A: No crack was generated. Flexibility is extremely high.
○: Slight cracks occurred. Flexibility is high.
Δ: Slightly large cracks occurred. Flexibility is somewhat low.
X: A crack was completely generated. Flexibility is low.

<Skin irritation>
The test was conducted with reference to the Draize method. The ink composition was used to prepare a 15% solution (in corn oil), immersed in an adhesive bandage, and then applied to a rabbit so as to be in contact with the skin for 24 hours. After 24 hours, the adhesive bandage was peeled off and judged by visual observation after 1 hour. The results are shown in Table 2.
○: Almost no change is observed.
Δ: Light erythema is observed.
×: Heavy red spots and water bubbles are observed

(Examples 2 to 21 and Comparative Examples 1 to 5)
Ink compositions 2 to 21 and comparative ink compositions 1 to 5 were prepared in the same manner as the ink composition 1 except that the components and amounts in the ink composition 1 were changed as shown in Table 1. Example 1 And evaluated in the same manner. The results are shown in Table 2.

Claims (10)

(A) a compound represented by formula (A-1) and / or formula (A-2),
(B) an ethylenically unsaturated compound having an alicyclic skeleton,
(C) other polymerizable compounds, and
(D) contains a polymerization initiator,
An ink composition comprising the compound represented by the formula (A-1) and the formula (A-2) in an amount of 3% by weight or more based on the total weight of the ink composition.

In Formula (A-1) and Formula (A-2), R ¹ represents a hydrogen atom or a methyl group, R ² and R ³ each independently represent a methylene group or an ethylene group, and R ⁴ represents a hydrogen atom or a carbon group. Represents an alkyl group having 1 to 5 atoms, R ⁵ and R ⁶ each independently represent a hydrogen atom and an alkyl group having 1 to 5 carbon atoms, and R ⁵ and R ⁶ are bonded to each other to form a ring; In addition, L ¹ represents a divalent linking group.   The ink composition according to claim 1, wherein the polymerization initiator (D) includes a radical polymerization initiator.   The ink composition according to claim 1, wherein the polymerization initiator (D) is an aromatic ketone and / or an acylphosphine compound.   (E) The ink composition according to any one of claims 1 to 3, comprising a colorant.   The compound represented by the formula (A) and / or the formula (A-2) is acrylic acid (3-ethyl-3-oxetan-3-yl) methyl, 4-acryloyloxymethyl-2 -Methyl-2-ethyl-1,3-dioxolane, 4-acryloyloxymethyl-2-methyl-2-isobutyl-1,3-dioxolane and 4-acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane The ink composition according to any one of claims 1 to 4, which is at least one selected from the group. The ink according to claim 1, wherein the (B) ethylenically unsaturated compound having an alicyclic skeleton is a compound represented by the formula (BI) or the formula (B-II). Composition.

In formulas (BI) and (B-II), R ¹ represents a hydrogen atom or a methyl group, X ¹ represents a divalent linking group, k represents an integer of 1 to 6, and q R ² and r R ³ each independently represent a substituent, q represents an integer of 0 to 5, r represents an integer of 0 to 5, and the compound represented by the formula (B-II) is Y It may have a cyclic hydrocarbon structure represented by ¹ .   The ethylenically unsaturated compound (B) having an alicyclic skeleton is at least one selected from the group consisting of dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate and isobornyl (meth) acrylate. The ink composition according to any one of claims 1 to 6, which is a compound.   The ink composition according to any one of claims 1 to 7, comprising an acyclic polyfunctional ethylenically unsaturated compound as the other polymerizable compound (C). (A ¹⁾ onto a recording medium, a step of discharging the ink composition according to any one claims 1 to 8 and,
(B ¹ ) A step of irradiating the discharged ink composition with actinic radiation to cure the ink composition. A printed matter recorded by the ink jet recording method according to claim 9.