JP2012193230A - Active energy ray-curable inkjet ink composition and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ultraviolet-curable inkjet ink that has high photocuring sensitivity and provides a high-quality image excellent in weather resistance, and an inkjet recording method using the inkjet ink.SOLUTION: The active energy ray-curable inkjet ink composition contains a pigment and at least two polymerizable compounds each having an unsaturated double bond, wherein the moieties of the unsaturated double bonds included in the at least two polymerizable compounds have difference in e value of 2.8-6, and a compound which is unpolymerizable and has a substituent capable of reacting with a nucleophilic agent is contained.

Description

  The present invention relates to a novel active energy ray-curable inkjet ink composition and an inkjet recording method.

  In recent years, the inkjet recording method has been used in various printing fields such as photographs, various printing, marking, and special printing such as color filters from the viewpoint of being able to create an image easily and inexpensively.

  As an inkjet ink used in such an inkjet recording system, an aqueous inkjet ink containing water as a main solvent, a non-volatile solvent that does not volatilize at room temperature, an oil-based inkjet ink that does not substantially contain water, and volatilizes at room temperature. Non-water-based inkjet ink that contains mainly solvent and contains substantially no water, hot-melt ink that heats and melts solid ink at room temperature, and active energy ray-curable inkjet that cures with actinic rays such as ultraviolet rays after printing There are various types of ink-jet inks, such as inks, and they have been properly used according to the application. Among them, the active energy ray-curable ink-jet ink has a fast curing property and can be used on a wide variety of recording media. However, because of the feature that printing is possible, the drying load is large and the recording medium is limited. The aqueous inkjet ink and that, oil-based inkjet ink, has attracted attention as a next-generation inkjet ink to replace the non-aqueous inkjet ink, a large expected that expanding applications.

  Conventionally, active energy ray-curable inkjet inks are mainly classified into radical polymerization type and cationic polymerization type inkjet inks. Radical polymerization type ink-jet inks are widely researched and developed and put to practical use because they have a wide range of material choices and a high degree of freedom in ink design. However, there is a problem that the handling is careful because it is easily affected by the inhibition of polymerization by oxygen, the odor of the polymerizable compound (monomer) and the skin sensitization. On the other hand, although the cationic polymerization type ink-jet ink is not affected by the inhibition of polymerization by oxygen, it has been a problem that the polymerization is inhibited by the influence of humidity, and there are few material variations and the price is high.

  Monomers with low e-values such as vinyl ether and monomers with high e-values such as maleimide for the purpose of achieving both safety of materials used such as polymerizable compounds (monomers), polymerization initiators and sensitizers, and practical curing sensitivity. The charge transfer complex polymerization reaction (abbreviated as CT polymerization reaction, for example, Sonny Johnson, et.al, Polymer Materials Sci. & Engineer. 1995, 72, 470-472) is described in detail. ) Is applied to an active energy ray-curable composition such as ultraviolet rays (see, for example, Patent Documents 1, 2, and 3).

  However, the authors have found that there is a problem that sufficient strength cannot be ensured for a film formed from this CT polymerization type ink-jet ink. In particular, when a light source with low illuminance, such as an LED, is used, the resistance (weather resistance) to outdoor light and rain tends to be insufficient. In recent years, an active energy ray-curable ink that is cured with a smaller amount of light is required for an inkjet system, and even the CT polymerization type inkjet ink cannot meet the demand.

Japanese Patent No. 3353020 Japanese Patent Laid-Open No. 11-124403 JP 2003-213171 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultraviolet curable inkjet ink that has high photocuring sensitivity and is capable of obtaining a high-quality image with excellent weather resistance, and an inkjet recording method using the inkjet ink. It is to provide.

  The above object of the present invention is achieved by the following configurations.

  1. An active energy ray-curable inkjet ink composition containing at least two kinds of a polymerizable compound having a pigment and an unsaturated double bond, wherein e is an unsaturated double bond portion of the at least two kinds of polymerizable compounds An active energy ray-curable inkjet ink composition comprising a compound having a value difference of 2.8 or more and 6 or less and having a non-polymerizable substituent capable of reacting with a nucleophile.

  2. Among the polymerizable compounds having at least two types of unsaturated double bonds, the polymerizable compound having the maximum e value is an unsaturated compound represented by the following general formula (1) or general formula (2). 2. The active energy ray-curable inkjet ink composition as described in 1 above, wherein the polymerizable compound having the minimum e value is an unsaturated compound represented by the following general formula (3).

[Wherein, EWG ₁ and EWG ₂ each represent an electron-withdrawing group, and a part of EWG ₁ or EWG ₂ may be bonded to form a cyclic structure. The electron-withdrawing group represents a cyano group, a halogen group, a pyridyl group, a pyrimidyl group, a nitro group, a group represented by the following general formula (a), or a group represented by the following general formula (b). EWG ₁ and EWG ₂ may be bonded to each other to form the following electron-withdrawing linking group to form a cyclic structure. As the linking group, —CO—O—CO—, —CO—N (R _X ) —CO—, —S (O) _n —O—CO—, —S (O) _n —N (R) —CO _{-, - S (O) n} -O-S (O) n -, or _{-S (O) n -N (R} X) -S (O) n - can be exemplified. EWG ₁ and EWG ₂ may form a cyclic structure via a linking group such as a linear alkylene group, a branched alkylene group, a cyclic alkylene group, an alkylene group having a hydroxyl group, an arylene group or an arylalkylene group, and a substituent. You may have. Further, a part of EWG ₁ or EWG ₂ may form a polyfunctional polymerizable compound having two or more unsaturated bonds through a linking group. R _X represents a substituent. ]

[Wherein Q ₁ represents OH, OR ′, NR′R ″ or R ′. R ′ and R ″ each have a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group or a hydroxyl group. An alkyl group, an aryl group or an arylalkyl group is represented. n represents 1 or 2. ]

[Wherein, X represents —O—, —NR _D —, —S—, or —SO—. Y represents a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group, or an arylalkyl group, and may further have a substituent. R _A , R _B , R _C and R _D each independently represent a hydrogen atom, a linear alkyl group, or a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group, or an arylalkyl group; It may have a substituent. Further, a part of R _B or R _C and Y may be bonded to form a cyclic structure. Moreover, you may form the polyfunctional polymerizable compound which one part of Y has a 2 or more unsaturated bond part through a coupling group. ]
3. The unsaturated compound represented by the general formula (1) or the general formula (2) is at least one unsaturated compound selected from the following general formula (A-1) to general formula (A-12). 3. The active energy ray-curable inkjet ink composition as described in 2 above.

[Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group or an arylalkyl group. And may further have a substituent, and can be a linking group for forming a polyfunctional polymerizable compound having two or more unsaturated bond moieties. X ₁ represents a halogen atom. ]
4). The unsaturated compound represented by the general formula (3) is at least one unsaturated compound selected from the following general formulas (D-1) to (D-9): Or the active energy ray-curable inkjet ink composition according to 3;

[Wherein R ₅ to R ₉ each independently represents a hydrogen atom, a linear alkyl group, or a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group or an arylalkyl group, and further a substituent. May be used as a linking group for forming a polyfunctional polymerizable compound having two or more unsaturated bond moieties. Z represents —O—, —N (R ₁₀ ) — or —S—. R ₁₀ represents a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group, or an arylalkyl group, and may further have a substituent. ]
5. The unsaturated compound represented by the general formula (1) or the general formula (2) is represented by the general formula (A-1), the general formula (A-2), or the general formula (A-5). The unsaturated compound represented by the general formula (3) is an unsaturated compound represented by the general formula (D-1), the general formula (D-2), or the general formula (D-3). 5. The active energy ray-curable inkjet ink composition as described in 4 above, which is a saturated compound.

  6). 6. The active energy ray-curable inkjet ink composition according to any one of 1 to 5, wherein the nucleophile is a compound containing a hydroxyl group or a carboxyl group.

  7). 7. The substituent according to any one of 1 to 6 above, wherein the substituent capable of reacting with the nucleophile is a group represented by the following general formula (4), (5), or (6): An active energy ray-curable inkjet ink composition.

[In General Formula (4), R _D represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. * Represents a binding site.

In General Formula (5), R _E represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. * Represents a binding site.

In general formula (6), * represents a binding site. ]
8). 8. An inkjet recording method comprising recording an image using the active energy ray-curable inkjet ink composition described in any one of 1 to 7 above.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an active energy ray-curable inkjet ink composition that has high curing sensitivity and forms an image having excellent durability even when posted outdoors for a long time, and an inkjet recording method using the same. It was.

It is a front view which shows an example of a structure of the principal part of the inkjet recording device used for the inkjet recording method of this invention. It is a top view which shows another example of a structure of the principal part of the inkjet recording device used for the inkjet recording method of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

  As a result of intensive studies in view of the above problems, the present inventor has found that the active energy ray-curable inkjet ink composition containing at least two polymerizable compounds having an unsaturated bond has an e of the at least two polymerizable compounds. An active energy ray-curable inkjet ink composition comprising a compound having a value difference of 2.8 or more and 6.0 or less and having a non-polymerizable substituent capable of reacting with a nucleophile It has been found that an active energy ray-curable inkjet ink composition capable of forming an image having high curing sensitivity and having excellent durability even when posted outdoors for a long period of time can be realized.

  The present inventor conducted an analysis on the problems of the active energy ray-curable inkjet ink composition (hereinafter also referred to as an ink composition or ink) as described above, and obtained the following estimation.

  That is, in the case of an application for posting an image outdoors as a poster, the image is always exposed to moisture such as sunlight, rain, and dew. Therefore, it is known that the image is decomposed under the influence of light, oxygen and moisture from the surface of the image. This also has the same effect on images formed using an active energy ray-curable ink, and the polymer formed from the polymerizable compound decomposes when posted over a long period of time, causing the image itself to crack, peel off, rain, etc. It will be affected by the outflow of moisture. In conventional printing, in order to reduce these effects, measures such as adding a large amount of a polyfunctional polymerizable compound to increase the degree of crosslinking and adding a large amount of polymer in advance have been taken.

  When an active energy ray curable ink is used for inkjet, it cannot be emitted when the viscosity is high, so the amount of polyfunctional polymerizable compound or polymer compound is limited, and the effects of light, oxygen, and moisture are affected. It is difficult to add an amount to reduce. In addition, when it is difficult to give a sufficient amount of integrated light, such as when using a light source with low illuminance such as an LED that prints at high speed, the degree of cross-linking in the formed film is insufficient and is particularly strongly affected by light, oxygen, and moisture. It became clear. It has also been found that this phenomenon is particularly noticeable when a so-called rigid base material such as plastic cardboard or resin board is used.

  In the case of a rigid base material, the surface is generally subjected to a modification treatment by corona discharge for the purpose of improving image quality and adhesion. Therefore, it is said that nucleophilic groups such as hydroxyl groups and carboxyl groups exist on the surface. These substituents have the ability to attack the polymer formed from the polymerizable compound in the image and to break the polymer chain to reduce the image resistance. Therefore, when an image is posted outdoors for a long time, in addition to the influence of light, oxygen, and moisture, these nucleophilic substituents also cut the polymer chain in the image and accelerate the peeling and outflow of the image. .

  It has been clarified by the authors that image degradation outdoors can be suppressed by adding a compound having a substituent capable of reacting with these nucleophilic substituents. This is considered to be because the substituent capable of reacting with the nucleophilic substituent reacts with the nucleophilic group quickly and thus renders it harmless before the polymer chain is cleaved. In particular, since these compounds are non-polymerizable, they exist independently of the polymer chain formed from the polymerizable compound in the ink, and it is considered that the influence on the polymer chain can be minimized.

<< Inkjet ink composition >>
First, details of each component of the inkjet ink composition of the present invention will be described.

[E value of unsaturated bond part of polymerizable compound]
Hereinafter, the e value according to the present invention will be described.

  The Q-e concept is described in POLYMER HANDBOOK FORTH EDITION Volume 1, (editor J. BRANDRUP, EH IMMERGUT, and EA GRULKE, publication year 1999, publisher Wiley-Interscience Publication). It is known as a semi-empirical theory for organizing and predicting monomer reactivity ratios in radical copolymerization. In the above-mentioned reference, the e value is derived by calculation from the empirically obtained monomer reactivity ratios r1 and r2. The e value of the polymerizable compound according to the present invention can also be determined according to the calculation formula described in the above-mentioned reference. However, according to the inventors' investigation, the e value of the polymerizable compound having the same or similar structure is used. I found that it could be substituted. That is, the e value of a polymerizable compound having a structure that is the same as or close to the unsaturated bond portion of the polymerizable compound according to the present invention, in which r1 and r2 are known and the e value has already been determined by calculation. The effect of the present invention can be explained by using. The ink composition of the present invention is characterized in that the difference in e value between at least two polymerizable compounds is 2.8 or more and 6.0 or less. If the difference between the e values is less than 2.8, CT polymerization is difficult to occur. On the other hand, if the difference in e value exceeds 6.0, the charge transfer complex is stabilized, and the polymerization rate is decreased.

(Monomer with high e value)
The monomer having a high e value according to the present invention is a polymerizable compound containing at least one unsaturated bond moiety having a structure that is the same as or similar to the polymerizable compound having a high e value. Among the polymerizable compounds having at least two unsaturated bonds, a monomer having a relatively high e value is indicated. The e value is 1.0 or more, preferably 1.5 or more.

  In the ink composition of the present invention, among the polymerizable compounds having at least two unsaturated bonds, the polymerizable compound having the maximum e value is represented by the general formula (1) or the general formula (2). An unsaturated compound is preferable.

In the general formula (1) or the general formula (2), EWG ₁ and EWG ₂ each represent an electron-withdrawing group, and a part of EWG ₁ or EWG ₂ may be bonded to have a cyclic structure. . The electron-withdrawing group represents a cyano group, a halogen group, a pyridyl group, a pyrimidyl group, a nitro group, or a group represented by the general formula (a) or the general formula (b). EWG ₁ and EWG ₂ may be bonded to each other to form the following electron-withdrawing linking group to form a cyclic structure. As the linking group, —CO—O—CO—, —CO—N (R _X ) —CO—, —S (O) _n —O—CO—, —S (O) _n —N (R) —CO _{-, - S (O) n} -O-S (O) n -, or _{-S (O) n -N (R} X) -S (O) n - can be exemplified. EWG ₁ and EWG ₂ may form a cyclic structure via a linking group such as a linear alkylene group, a branched alkylene group, a cyclic alkylene group, an alkylene group having a hydroxyl group, an arylene group or an arylalkylene group, and a substituent. You may have. Further, a part of EWG ₁ or EWG ₂ may form a polyfunctional polymerizable compound having two or more unsaturated bonds through a linking group.

In the general formulas (a) and (b), Q ₁ represents OH, OR ′, NR′R ″ or R ′. R ′ and R ″ each represent a hydrogen atom, a linear alkyl group, or a branched alkyl group. Represents a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group or an arylalkyl group, and may further have a substituent.

  Specific examples of the unsaturated compound represented by the general formula (1) or the general formula (2) include, for example, a vinylene imide compound, a vinylene dicarboxylic acid, a vinylene dicarboxylic acid ester, a vinylene monocarboxylic acid amide monocarboxylic acid, and a vinylene monocarboxylic acid. Acid amide monocarboxylic acid ester, vinylene dicarboxylic acid amide, vinylene nitrile compound substituted with nitrile groups at both ends of vinylene skeleton, vinyl halide compound substituted with halogen groups at both ends of vinylene skeleton, vinylene ketone compound substituted with carbonyl at both ends of vinylene skeleton , Vinylene dithiocarboxylic acid anhydride, vinylene thioimide compound, vinylene dithiocarboxylic acid, vinylene dithiocarboxylic acid ester, vinylene monothiocarboxylic acid amide monothiocarboxylic acid, vinylene monothiocarboxylic acid amido Thiocarboxylic acid esters, vinyl range thio carboxylic acid amide, compounds pyridyl group which is substituted vinylene backbone ends, but such compounds structure pyrimidyl group is substituted on vinylene skeleton ends include, but are not limited to.

  Among these, preferable unsaturated compounds include vinylene imides such as maleimide, vinylene dicarboxylic acids such as maleic acid and fumaric acid, and vinylene dicarboxylic acid esters such as maleic acid esters and fumaric acid esters.

  Moreover, in this invention, the unsaturated compound represented by General formula (1) or General formula (2) is at least 1 sort (s) chosen from the said General formula (A-1)-General formula (A-12). An unsaturated compound is preferred.

In the general formula (A-1) to general formula (A-12), R ₁ , R ₂ , R ₃ , and R ₄ each independently represent a hydrogen atom, a linear alkyl group, a branched alkyl group, or a cyclic alkyl. A group, a hydroxyl group-containing alkyl group, an aryl group or an arylalkyl group, which may further have a substituent, and a linking group for forming a polyfunctional polymerizable compound having two or more unsaturated bonds; can do. X ₁ represents a halogen atom.

  In the unsaturated compound represented by the general formula (1) or the general formula (2) according to the present invention, preferably the unsaturated compound represented by the general formula (A-1) to the general formula (A-12). Furthermore, it is preferable that it is an unsaturated compound represented by general formula (A-1), general formula (A-2), or general formula (A-5).

  Below, an example of e value of the unsaturated bond part of the polymeric compound which concerns on this invention represented by general formula (A-1)-general formula (A-12) is shown. In addition, the following e value is excerpted from POLYMER HANDBOOK FORTH EDITION Volume 1, (editor J. BRANDRUUP, EH IMMERGUT, and E.A. GRULKE, issue year 1999, publisher Wiley-Interscience Publication) is there.

1) General formula (A-1): e value 3.70 (when R ₁ is aliphatic; N-butylmaleimide value is substituted), e value 3.24 (when R ₁ is aromatic; N— (Substitutes the value of phenylmaleimide)
2) General formula (A-2): e value of 1.08 (diethyl maleate value substituted)
4) General formula (A-5): e value of 2.26 (value of diethyl fumarate substituted)
5) General formula (A-9): e value 2.73 (substitute the value of fumaronitrile)
6) General formula (A-12): e value of 2.23 (the value of 4-cyclopentene-1,3-dione is substituted)
In the present invention, examples of the monofunctional polymerizable compound having a preferable unsaturated bond moiety include the following examples. Examples of compounds having vinylene imide include maleimide, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-2-ethylhexylmaleimide, N-dodecylmaleimide, N-octadecylmaleimide, N-phenylmaleimide, N-cyclohexyl Maleimide, N- (p-carbomethoxyphenyl) maleimide, 4,4'-dimaleimidobisphenol F, N-butylmaleimide, N- (2-chlorophenyl) maleimide, N- (4-chlorophenyl) maleimide, 2,3- Examples of dimethyl-1-N- (2-methacryloxyethylmaleimide, vinylene dicarboxylic acid, maleic acid, fumaric acid, vinylene dicarboxylic acid ester, dimethyl maleate, diethyl maleate, diisopropyl maleate Di-n-butyl maleate, di-tert-butyl maleate, di (2-ethylhexyl) maleate, dimethyl fumarate, diethyl fumarate, diisopropyl fumarate, di-n-butyl fumarate, di-tert fumarate -Butyl, di (2-ethylhexyl) fumarate, and the like can be mentioned, but none is limited to these specific examples.

  In order to obtain the polyfunctional polymerizable compound having a preferable unsaturated bond moiety, it can be obtained by using various conventionally known linking group skeletons. Examples thereof include polyfunctional maleimide derivatives as described in US Pat. No. 6,034,150 and Patent Document 2.

  Below, the maleimide derivative which can be preferably used for an active energy ray hardening-type inkjet ink composition is demonstrated in detail.

  The maleimide compound according to the present invention is preferably a maleimide compound having a chiral structure in the molecule from the viewpoints of solubility, low viscosity, and ejection stability required as an inkjet ink composition.

  In the present invention, the maleimide compound having a chiral group preferably has at least one chiral carbon atom in the molecule. Furthermore, as the maleimide compound, a compound represented by the following general formula (M) Is preferred.

General formula (M)
_{Z 1 - (Y 1) n1} - (Y 2) n2 - (Y 3) n3 - (Y 4) n4 - (Y 5) n5 -Z 2
In the general formula (M), Z ₁ and Z ₂ may have a maleimide group, a hydrogen atom, a hydroxyl group, an alkoxy group, an oxycarbonyl group, an alkyloxycarbonyl group, or a substituent, which may have a substituent. Represents a good amino group. However, at least one of Z ₁ and Z ₂ represents a maleimide group.

  Examples of the substituent of the maleimide group include an alkyl group having 1 to 6 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group). In addition, they may be bonded to each other to form a cyclopropylene ring, a cyclobutylene ring, a cyclopentene ring, a cyclohexene ring, or the like.

Z ₁ and Z ₂ are a maleimide group, a hydrogen atom, a hydroxyl group, preferably an alkoxy group having 1 to 8 carbon atoms (for example, methoxy group, propoxy group, 2-ethylhexyloxy group), an oxycarbonyl group, preferably 1 carbon atom. To 8 alkyloxycarbonyl groups (for example, methoxycarbonyl group, ethoxycarbonyl group, isobutoxycarbonyl group, hexylcarbonyl group) and optionally substituted amino groups (for example, amino group, methylamino group, 2-hydroxyethyl group) Amino group) and the like.

Y ₁ , Y ₃ and Y ₅ represent a divalent organic linking group in which groups selected from an alkylene group, an alkyleneoxy group, a phenylene group, an ester group, an ether group and a thioether group are combined, and Y ₂ and Y ₄ Represents a divalent group having an asymmetric carbon. n1, n2, n3, n4, and n5 each represents 0 or 1. However, n1 + n3 + n5 is an integer of 0 to 3, and n2 + n4 represents 1 or 2.

Examples of the divalent organic linking group represented by Y ₁ , Y ₃ , and Y ₅ include an alkylene group (for example, a methylene group, an ethylene group, a butylene group, a hexylene group), an alkyleneoxy group (for example, an ethyleneoxy group, Polyethyleneoxy group, butyleneoxy group, polybutyleneoxy group), alkyleneoxycarbonyl group (eg, ethyleneoxycarbonyl group, hexyleneoxycarbonyl group, etc.), alkylene ester group (eg, methylene ester group, hexylene ester group, etc.) Phenylene group (for example, methylphenylene group), oxycarbonylphenylenecarbonyloxy group, carbonyloxyphenyleneoxycarbonyl group, ether group, thioether group and the like.

Y ₂ and Y ₄ represent a divalent group having an asymmetric carbon (chiral carbon). Specifically, the following formula may be mentioned.

In the formula, X ₂ represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an oxyalkyl group having 1 to 18 carbon atoms, an alkyloxycarbonyl group having 1 to 18 carbon atoms, or a hydroxyl group. Preferably, the alkyl group having 1 to 4 carbon atoms (for example, methyl group, ethyl group, propyl group, isobutyl group), the oxyalkyl group having 1 to 4 carbon atoms (for example, methoxy group, isopropoxy group), 1 to 6 carbon atoms. Alkyloxycarbonyl groups (for example, methoxycarbonyl group, ethoxycarbonyl group, isobutoxycarbonyl group, hexylcarbonyl group) and the like.

  Of these maleimide compounds having a chiral group, a structure in which a chiral carbon is directly bonded to the maleimide group is particularly preferred. For example, in the general formula M, it is preferable that either n1 or n5 or both are 0.

  For emission from an inkjet head, the molecular weight of the maleimide compound having a chiral group is 200 to 1000, preferably 300 to 800, and more preferably 400 to 700. If it is less than 200, crystallization is likely and clogging is likely to occur during emission. On the other hand, if the molecular weight is larger than 1000, the viscosity becomes high and the emission becomes difficult. Furthermore, since the degree of crosslinking of the formed image becomes small, a tendency to be inferior in outdoor durability, which is an effect of the present invention, can be seen.

  More preferably, the maleimide compound represented by the following structural formula is mentioned.

Here, n11 and n12 are preferably integers of 0 to 6, and n13 is preferably an integer of 1 to 30. Examples of R ₁₁ and R ₁₂ include a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group). In addition, they may be bonded to each other to form a cyclopropylene ring, a cyclobutylene ring, a cyclopentene ring, a cyclohexene ring, or the like. Z _A represents an n-valent linking group. Preferably n is 1-4. Z _A is hydrogen atom, alkyl group (methyl group, ethyl group, hexyl group), hydroxyl group, carboxyl group, alkyl ester group, etc., when n = 1, simple bond, carbon number when n = 2 An alkylene group having 1 to 18 carbon atoms, an alkenylene group having 1 to 18 carbon atoms, an oxyalkylene group having 1 to 18 carbon atoms, and an alkyloxycarbonyl group having 1 to 18 carbon atoms. X ₃ has the same meaning as the _{X 2.} W represents a hydrogen atom or a methyl group.

  Although the specific example of a compound represented by general formula (M) below is shown, this invention is not limited to this.

  Methods for synthesizing these maleimide compounds are known, and can be easily synthesized using, for example, the method described in Patent Document 2 or Macromolecular Chemical and physics, 2009, 210, 269-278.

(Monomer with low e value)
The monomer having a low e value according to the present invention is a polymerizable compound containing at least one unsaturated bond moiety having the same or similar structure as the polymerizable compound having a low e value. Among the polymerizable compounds having at least two unsaturated bonds, a monomer having a relatively low e value is indicated. The e value is preferably −1.0 or less, more preferably −1.5 or less.

  In the ink composition of the present invention, among the polymerizable compounds having at least two unsaturated bonds, the polymerizable compound having the minimum e value is the unsaturated compound represented by the general formula (3). Preferably there is.

In the general formula (3), X represents —O—, —NR _D —, —S—, or —SO—. Y represents a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group, or an arylalkyl group, and may further have a substituent. R _A , R _B , R _C and R _D each independently represent a hydrogen atom, a linear alkyl group, or a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group or an arylalkyl group; It may have a substituent. Further, a part of R _B or R _C and Y may be bonded to form a cyclic structure. Moreover, you may form the polyfunctional polymerizable compound which one part of Y has a 2 or more unsaturated bond part through a coupling group.

  In the polymerizable compound having an unsaturated bond moiety represented by the general formula (3) according to the present invention, a monofunctional polymerizable compound having one unsaturated bond moiety, or Y has a linking group structure moiety, A polyfunctional polymerizable compound having two or more unsaturated bond moieties may be formed.

  Specific examples of the unsaturated compound represented by the general formula (3) according to the present invention include alkenyl ethers such as vinyl ether and propenyl ether, alkenyl thioethers such as vinyl thioether and propenyl thioether, vinyl sulfoxide, propenyl sulfoxide and the like. Alkenyl sulfoxides, vinyl esters in which a vinyl group is bonded to the oxygen atom of a carboxylic acid ester, vinylamines in which a vinyl group is bonded to the nitrogen atom of an amino group, vinylamides in which a vinyl group is bonded to the nitrogen atom of an amide group, imidazole Examples include vinylimidazole in which a vinyl group is bonded to the nitrogen atom of the ring, vinylcarbazole in which a vinyl group is bonded to the nitrogen atom of the carbazole ring, a cyclic 5-membered ring containing a vinylene skeleton and an oxygen atom in the ring, and a cyclic 6-membered ring compound. It is done.

  The unsaturated bond portion represented by the general formula (3) according to the present invention is at least one unsaturated compound selected from the general formula (D-1) to the general formula (D-9). preferable.

In the general formulas (D-1) to (D-9), R ₅ to R ₉ are each independently a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, or an alkyl having a hydroxyl group. Represents a group, an aryl group or an arylalkyl group, may further have a substituent, and can be a linking group for forming a polyfunctional polymerizable compound having two or more unsaturated bond moieties. Z represents —O—, —N (R ₁₀ ) — or —S—. R ₁₀ represents a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group, or an arylalkyl group, and may further have a substituent.

  Subsequently, an example of e value of the unsaturated bond part of the polymeric compound which concerns on this invention represented by general formula (D-1)-general formula (D-9) is shown. In addition, the following e value is excerpted from POLYMER HANDBOOK FORTH EDITION Volume 1, (editor J. BRANDRUUP, EH IMMERGUT, and E.A. GRULKE, issue year 1999, publisher Wiley-Interscience Publication) is there.

1) General formula (D-1): e value −6.86 (when R ₈ is aromatic: the value of vinyl-m-cresyl ether is substituted), −1.80 (when R ₈ is aliphatic: (The value of vinyl ethyl ether is used instead)
2) General formula (D-2): e value -1.29 (the value of N-vinylcarbazole is substituted)
3) General formula (D-3): e value -1.18 (the value of N-vinylcaprolactam is substituted)
4) General formula (D-6): e value -1.79 (value of vinyl methyl sulfoxide substituted)
5) General formula (D-7): e value −1.66 (value of vinyl methyl sulfide is substituted)
Furthermore, the polymerizable compound which has the following vinyl ether groups as a polymerizable compound which has a preferable unsaturated bond part is mentioned.

  Examples of vinyl ether compounds include the following.

<Bifunctional vinyl ether compound>
Bifunctional vinyl ether compounds include 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, nonanediol divinyl ether, cyclohexanediol divinyl ether, cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether. , Triethylene glycol divinyl ether (TEGDVE), trimethylolpropane divinyl ether, ethylene oxide-modified trimethylolpropane divinyl ether, pentaerythritol divinyl ether, and the like.

  In addition, a vinyl ether compound having an alicyclic skeleton containing at least an oxygen atom disclosed in Japanese Patent No. 4037856, a vinyl ether having an alicyclic skeleton disclosed in Japanese Patent Application Laid-Open No. 2005-015396, 1-indanyl vinyl ether disclosed in JP-A-137974, 4-acetoxycyclohexyl vinyl ether disclosed in JP-A-2008-150341, and the like.

  In addition, by introducing a substituent at the α-position or β of the vinyl ether group, such as by substituting the vinyl ether group of the above-mentioned divinyl ether with a propenyl ether group, an isopropenyl ether group, a butenyl ether group, or an isobutenyl ether group. You can also.

  Among these bifunctional vinyl ether compounds, in consideration of curability, adhesion, and surface hardness, diethylene glycol divinyl ether and triethylene glycol divinyl ether, cyclohexanediol divinyl ether, cyclohexanedimethanol divinyl ether are curable, and various materials Are excellent in terms of compatibility, odor, and safety.

<Trifunctional or higher polyfunctional vinyl ether compound>
Specific examples of the trifunctional or higher polyfunctional vinyl ether compound suitable for the present invention include trimethylolpropane trivinyl ether, ethylene oxide modified trimethylolpropane trivinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, ethylene oxide modified pentaerythritol trivinyl ether. Examples include vinyl ether, ethylene oxide modified pentaerythritol tetravinyl ether, dipentaerythritol hexavinyl ether, ethylene oxide modified dipentaerythritol hexavinyl ether, and the like.

  As a trifunctional vinyl ether compound, a compound having an oxyalkylene group in the molecule, such as a compound represented by the following general formula (7), is compatible with other compounds, has solubility, and adherence to a substrate. It is preferable in obtaining. The total number of oxyalkylene groups is preferably 10 or less. When it is larger than 10, the water resistance of the cured film is lowered. In the following general formula (7), an oxyethylene group is exemplified, but an oxyalkylene group having a different carbon number may be used. The number of carbon atoms in the oxyalkylene group is preferably 1 to 4, and more preferably 1 or 2.

In the general formula (7), R ₂₁ represents hydrogen or an organic group. Examples of the organic group represented by R ₂₁ include an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group, a fluoroalkyl group having 1 to 6 carbon atoms, an aryl group, and a furyl group. Or thienyl group, allyl group, 1-propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group or 3-butenyl group, etc. An alkenyl group having 1 to 6 carbon atoms, phenyl group, benzyl group, fluorobenzyl group, aryl group such as methoxybenzyl group or phenoxyethyl group, alkoxy group such as methoxy group, ethoxy group and butoxy group, propylcarbonyl group, C1-C6 alkylcarbonyl group such as butylcarbonyl group or pentylcarbonyl group, ethoxycarbonyl group, propoxy Examples thereof include a group such as an alkoxycarbonyl group having 1 to 6 carbon atoms such as a carbonyl group or a butoxycarbonyl group, an alkoxycarbamoyl group having 1 to 6 carbon atoms such as an ethoxycarbamoyl group, a propylcarbamoyl group or a butylpentylcarbamoyl group. It is not limited to these. Among these, as the organic group, a hydrocarbon group containing no hetero atom is preferable from the viewpoint of curability. Moreover, p, q, and r are 0 or an integer greater than or equal to 1, and p + q + r is an integer of 3-10.

  Examples of the polyfunctional vinyl ether compound having 4 or more vinyl ether groups include compounds represented by the following general formulas (8) and (9).

In the general formula (8), R ₂₂ is a linking group containing any one of a methylene group, an alkylene group having 1 to 6 carbon atoms, an oxyalkylene group, and an ester group, and p, q, l, and m are each 0. Or it is an integer greater than or equal to 1, and the total number of p + q + l + m is an integer of 3-12.

In the general formula (9), R ₂₃ represents a linking group including any one of a methylene group, an alkylene group having 1 to 6 carbon atoms, an oxyalkylene group, and an ester group, and p1, q1, r1, l1, m1 , S1 are each an integer of 0 or 1 or more, and the total number of p1 + q1 + r1 + l1 + m1 + s1 is an integer of 3-12.

  In the general formulas (8) and (9), an oxyethylene group is exemplified, but an oxyalkylene group having a different carbon number may be used. The number of carbon atoms in the oxyalkylene group is preferably 1 to 4, and more preferably 1 or 2.

  In the present invention, the trifunctional or higher polyfunctional vinyl ether is more preferably tetrafunctional or higher in order to obtain excellent curing characteristics such as solvent resistance and weather resistance of the cured film.

  In addition, the above-described trifunctional or higher polyfunctional vinyl ether is preferably a functional group represented by the following general formula (10) as a vinyl ether group in order to improve curing sensitivity and reduce odor.

In the general formula (10), R ₃₁ and R ₃₂ each represent a hydrogen atom or an organic group, and the total number of carbon atoms of the organic group of R ₃₁ and R ₃₂ is an integer of 1 or more.

[Monofunctional vinyl ether compound]
Examples of the monofunctional vinyl ether compound include n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, allyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, 9-hydroxy. Nonyl vinyl ether, 4-hydroxycyclohexyl vinyl ether, cyclohexanedimethanol monovinyl ether, triethylene glycol monovinyl ether and the like can be mentioned.

  In addition to the above, various vinyl ether compounds disclosed so far can be applied. For example, a compound containing a (meth) acryloyl group and a vinyl ether group in the molecule disclosed in Japanese Patent No. 3461501, a vinyl ether compound having a heterocyclic skeleton containing at least an oxygen atom disclosed in Japanese Patent No. 4037856 , Vinyl ethers having an alicyclic skeleton disclosed in Japanese Patent Application Laid-Open No. 2005-015396, 1-indanyl vinyl ether disclosed in Japanese Patent Application Laid-Open No. 2008-137974, and Japanese Patent Application Laid-Open No. 2008-150341. 4-acetoxycyclohexyl vinyl ether and the like can be mentioned.

  A polyfunctional (bifunctional or higher functional) vinyl ether has a cyclic skeleton such as an alicyclic ring or an aromatic ring, and a highly hydrophobic monomer is preferable from the viewpoint of less yellowing of the cured film.

  Among cyclic skeletons, alicyclic is superior in sensitivity to aromatic rings having UV absorption, and high sensitivity is obtained compared to a heterocyclic containing a hetero atom such as an oxygen atom in the ring. Particularly preferred. Moreover, alicyclic is preferable from the viewpoint of odor.

  As the cyclic skeleton, cyclopentane ring, cyclohexane ring, dicyclohexane ring, dicyclopentadiene ring, norbornene ring, isobornene ring, adamantane ring, and the like homocyclic alicyclic group, benzene ring, naphthalene ring, Homocyclic aromatic cyclic groups such as biphenyl ring and pyrene ring, epoxy ring, oxetane ring, thiophene ring, pyrrole ring, furan ring, pyridine ring, pyrrolidine ring, piperidine ring, piperazine ring, morpholine ring, dioxane ring Quinuclidine ring, tetrahydrofuran ring, aziridine ring, dithiane ring, pyrazole ring, triazole ring, imidazole ring, oxazole ring, thiazole ring, pyridone ring, quinolone ring, indole ring, benzotriazole ring, quinoline ring, isoquinoline ring, pyridazine ring, Pyrimidine ring, pyrazine ring Thiadiazole ring, an isoxazole ring, a heterocyclic ring group, such as an isothiazole ring, and the like.

  Examples of the monomer having an aromatic ring skeleton include hydroquinone divinyl ether and bisphenol A divinyl ether. Further, these aromatic rings may be substituted with a linear or branched alkyl group or alkoxyl group.

  Monomers having a heterocyclic skeleton include oxetane methanol divinyl ether, oxapentanediol divinyl ether, oxacyclohexanediol divinyl ether, oxanorbornanediol divinyl ether, oxanorbornane dimethanol divinyl ether, oxatricyclodecanediol divinyl ether, oxaadamantanediol Examples thereof include divinyl ether and dioxolanmentanol divinyl ether. Moreover, the monomer which made the oxetane ring and the hydrofuran ring bridge | crosslinking frame | skeleton like patent 4037856 is also mentioned.

  Monomers having an alicyclic skeleton include cyclopentanediol divinyl ether, cyclopentane dimethanol divinyl ether, tricyclodecane diol divinyl ether, tricyclodecane dimethanol divinyl ether, adamantane diol divinyl ether, cyclohexane diol divinyl ether, cyclohexane di Examples include methanol divinyl ether, norbornyl dimethanol divinyl ether, and isobornyl divinyl ether.

  Among these, as described above, from the viewpoint of curing sensitivity, cured film yellowing, and odor, cyclohexanediol divinyl ether, cyclohexane dimethanol divinyl ether, norbornyl dimethanol divinyl ether having an alicyclic skeleton that does not contain heteroatoms, Bornyl divinyl ether, more preferably cyclohexanediol divinyl ether and cyclohexanedimethanol divinyl ether are preferred.

  As other polymerizable compounds having an alkenyl ether group, for example, 1) Crevello, Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 31, 1473-1482 (1993), 2) Crevello, Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 33, 1381-1389 (1995), 3) Oskar Nuyken, et, al, Macromol. Chem. Phys. 199, 191-196 (1998) and the like, and the compounds described in each document can be mentioned.

  Examples of the polymerizable compound containing vinyl thioether and vinyl sulfoxide include vinyl methyl sulfoxide, vinyl tert-butyl sulfide, vinyl methyl sulfide, and vinyl ethyl sulfide.

  Examples of the polymerizable compound having a cyclic 5-membered ring or cyclic 6-membered ring compound containing a vinylene skeleton and an oxygen atom in the ring include imidazole, pyrrole, furan, dihydrofuran, pyran, and dihydropyran.

  Specific examples of the N-vinyl compound having a structure in which a vinyl group is substituted on a nitrogen atom include, for example, N-vinylformamide, N-vinylcarbazole, N-vinylindole, N-vinylpyrrole, N-vinylacetamide, N -Vinylpyrrolidone, N-vinylcaprolactam, N-vinyl-N-ethylurea, N-vinyloxazolidone, N-vinylsuccinimide, N-vinylethylcarbamate and derivatives thereof, among these compounds, especially N-vinylcaprolactam N-vinylformamide is preferred.

(Monomer addition ratio)
The addition ratio of the monomer (A) having a high e value and the monomer (B) having a low e value according to the present invention is such that the unsaturated bond molar ratio (A) / (B) of (A) and (B) is 2/8. From the viewpoint of curing sensitivity, a range of ˜8 / 2 is preferable, more preferably 2.5 / 7.5 to 7/3, and still more preferably 3/7 to 5/5. When the unsaturated bond molar ratio (A) / (B) is less than 2/8 or more than 8/2, residual monomers that are not cured increase, the film becomes sticky, and the strength is insufficient.

[Other monomers]
Examples of other polymerizable compounds include radically polymerizable compounds.

  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. Only one kind of radically polymerizable compound may be used, or two or more kinds thereof may be used in combination at an arbitrary ratio in order to improve desired properties. It is preferable to use two or more kinds in combination for controlling performance such as reactivity and physical properties. The inventors have confirmed that cyclic allyl sulfide monomers and other methacrylate monomers and acrylate monomers can be copolymerized.

  Examples of the polymerizable compound having an ethylenically unsaturated bond capable of radical polymerization include unsaturated carboxylic acids such as acrylic acid and methacrylic acid and salts thereof, anhydrides having an ethylenically unsaturated group, acrylonitrile, styrene, Examples thereof include radically polymerizable compounds such as various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes.

  Specifically, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, tridecyl acrylate, 2-phenoxyethyl acrylate, bis (4-acryloxypolyethoxyphenyl) Propane, polyethylene glycol diacrylate, polypropylene glycol diacrylate, dipentaerythritol tetraacrylate, trimethylolpropane triacrylate, oligoester acrylate, N-methylolacrylamide, diacetone acrylamide, epoxy acrylate, isobornyl acrylate, dicyclopentenyl acrylate, Dicyclopentenyloxyethyl acrylate, Acrylic acid derivatives such as cyclopentanyl acrylate; methyl methacrylate, n-butyl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2-bis (4- Methacryl derivatives such as methacryloxypolyethoxyphenyl) propane; and other derivatives of allyl compounds such as allyl glycidyl ether, diallyl phthalate, and triallyl trimellitate. More specifically, Shinzo Yamashita, “Crosslinker Handbook”, (1981 Taiseisha); Kato Kiyosumi, “UV / EB Curing Handbook (Materials)” (1985, Polymer Publications); Radtech Study Group, “Application and Market of UV / EB Curing Technology”, p. 79, (1989, CMC); Eiichiro Takiyama, “Polyester Resin Handbook”, (1988, Nikkan Kogyo Shimbun) Commercially available products or radically polymerizable and crosslinkable monomers, oligomers and polymers known in the industry can be used.

  Among these acrylates and methacrylates, alcohol acrylates having an ether oxygen atom such as tetrahydrofurfuryl acrylate and 2-phenoxyethyl acrylate are preferable from the viewpoints of curability and film properties after curing. For the same reason, an acrylate of an alcohol having an alicyclic structure is also preferable, and a bicyclo ring structure or a tricyclo ring structure such as isobornyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyl acrylate, etc. Specific examples of preferable acrylates include dicyclopentenyl acrylate and dicyclopentenyloxyethyl acrylate having a double bond in the alicyclic structure.

  Examples of the radically polymerizable compound include JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, JP-A-10-863, JP-A-9-134011, and JP-T-2004. There are known photocurable polymerizable compounds used in the photopolymerizable compositions described in JP-A-514014 and the like, and these can also be applied to the ink composition of the present invention.

  Other polymerizable compounds include (meth) acrylic monomers or prepolymers, (meth) acrylic acid esters such as epoxy monomers or prepolymers, urethane monomers or prepolymers (hereinafter referred to as acrylate compounds as appropriate). .) May be used, and the compounds shown below are listed as compound examples.

  That is, 2-ethylhexyl-diglycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxybutyl acrylate, hydroxypivalate neopentyl glycol diacrylate, 2-acryloyloxyethyl phthalate, methoxy-polyethylene glycol acrylate, Tetramethylol methane triacrylate, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, dimethylol tricyclodecane diacrylate, ethoxylated phenyl acrylate, 2-acryloyloxyethyl succinic acid, nonylphenol EO adduct acrylate, modified glycerin Triacrylate, bisphenol A diglycidyl ether acrylic acid adduct, modified bisphenol A diacrylate, phenoxy-poly Tylene glycol acrylate, 2-acryloyloxyethylhexahydrophthalic acid, PO adduct diacrylate of bisphenol A, EO adduct diacrylate of bisphenol A, dipentaerythritol hexaacrylate, pentaerythritol triacrylate tolylene diisocyanate urethane prepolymer Lactone-modified flexible acrylate, butoxyethyl acrylate, propylene glycol diglycidyl ether acrylic acid adduct, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, 2-hydroxyethyl acrylate, methoxydipropylene glycol acrylate, ditrimethylolpropane Tetraacrylate, pentaerythritol triacrylate hexamethyl Nji diisocyanate urethane prepolymer, stearyl acrylate, isoamyl acrylate, isomyristyl acrylate, isostearyl acrylate, lactone-modified acrylate, and the like.

  These acrylate compounds are polymerizable compounds that have been used in UV curable inks, have low skin irritation and sensitization (ease of rashes), and have relatively low viscosity and stable ink ejection properties. It is preferable because the sensitivity and adhesiveness with the recording medium are good.

  The monomers listed here as other polymerizable compounds are low in sensitization even with a low molecular weight, have high reactivity, low viscosity, and excellent adhesion to a recording medium.

  Monofunctional acrylate as monofunctional monomer, stearyl acrylate, isoamyl acrylate, isomistyl acrylate, isostearyl acrylate 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, as monofunctional monomer Examples thereof include ethylene glycol monovinyl ether and triethylene glycol monovinyl ether, and monofunctional acrylates are preferred. Among these, as monofunctional acrylates, stearyl acrylate, isoamyl acrylate, isomistyl acrylate, and isostearyl acrylate have high sensitivity and low shrinkage to prevent curling, and also prevent bleeding, odor of printed matter, and cost of irradiation equipment. This is preferable. Specifically, SR339, SR489, and SR506 (manufactured by Sartomer) can be preferably mentioned.

  As the oligomer that can be used in combination with the monofunctional acrylate, an epoxy acrylate oligomer and a urethane acrylate oligomer are particularly preferable.

  In addition, methacrylate has better skin irritation than acrylate.

  Examples of the bifunctional monomer include bifunctional acrylate, polyethylene glycol diacrylate, and polypropylene glycol diacrylate, and bifunctional acrylate is preferable.

  Specifically, SR508 and SR9045 (manufactured by Sartomer) can be preferably mentioned.

  Examples of the polyfunctional monomer include polyfunctional acrylate, dipentaerythritol tetraacrylate, trimethylolpropane triacrylate, and oligoester acrylate, and polyfunctional acrylate is preferable.

  Specifically, SR399 (manufactured by Sartomer) can be preferably mentioned.

[Photo radical polymerization initiator]
The ink composition of the present invention preferably contains a radical photopolymerization initiator and a sensitizer from the viewpoint of obtaining high sensitivity.

  As the radical photopolymerization initiator applicable to the ink composition of the present invention, those of molecular cleavage type or hydrogen abstraction type are suitable for the present invention. Specific examples include benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, benzyl, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpholino Phenyl) -butan-1-one, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and the like are preferably used. Further, other molecular cleavage types include 1-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4- Isopropyl fe ) -2-hydroxy-2-methylpropan-1-one and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 1- [4- (2-hydroxyethoxy)- Phenyl] -2-hydroxy-2-methyl-1-propan-1-one or the like may be used in combination, and hydrogen abstraction type photopolymerization initiators such as benzophenone, 4-phenylbenzophenone, isophthalphenone, 4- Benzoyl-4'-methyl-diphenyl sulfide, a metallocene type polymerization initiator bis (2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) ) -Phenyl) titanium, an oxime ester type polymerization initiator, 1,2-octanedione, 1- (4- (phenylthio) -, 2- (O-benzoyloxime)), ethanone, 1- (9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl)-, 1- (O-acetyloxime) and the like Can be used.

  In addition, as a sensitizer for the photo radical polymerization initiator, for example, trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, A radical polymerizable compound such as N, N-dimethylbenzylamine and 4,4′-bis (diethylamino) benzophenone can be used in combination with an amine that does not cause an addition reaction. Of course, the photo radical polymerization initiator and the sensitizer are preferably selected from those having excellent solubility in the radical polymerizable compound.

  The radical photopolymerization initiator and the sensitizer are in the range of 0.1 to 20% by mass, preferably 1 to 12% by mass with respect to the total mass of the active energy ray-curable inkjet ink composition.

  In addition, a dendrimer core described in European Patent 1,674,499A is bound to an amine-based initiator as an initiator structure, European Patent 2,161,264A, European Patent No. An initiator having a polymerizable group described in the specification of 2,189,477A, an amine-based initiator, and a plurality of amine-based initiators described in EP 1,927,632B1 are contained in one molecule. A type having a plurality of thioxanthones in the molecule described in WO2009 / 060235, an α hydroxypropiophenone represented by ESACURE ONE and ESACUR KIP150 marketed by Lamberti Oligomer type polymerization initiators bonded to can also be preferably used.

  In the present invention, when a maleimide-containing polymerizable compound is used, the maleimide-containing polymerizable compound itself can function as an initiator.

[Compounds having substituents capable of reacting with nucleophiles]
A feature of the present invention is that it contains a non-polymerizable compound having a substituent capable of reacting with a nucleophile.

As described above, nucleophilic substituents such as hydroxyl groups and carboxyl groups exist on the surface of the rigid base. In the present invention, a compound having a substituent that reacts with a hydroxyl group or a carboxyl group is particularly preferred. Examples of the substituent include -X (X represents a halogen atom or a nitro group), -OW (W represents an alkylcarbonyl group, an arylcarbonyl group, an alkylsulfonyl group, an arylsulfonyl group), an epoxy group, or the like. A cyclic ether group, -COOR _S (R _S represents an alkyl group or an aryl group, and may combine with other sites to form a cyclic structure), -COOCO-R _T (R _T is an alkyl group or an aryl group) And may be bonded to other sites to form a cyclic structure). Among them, the epoxy group represented by the general formula (4), the succinic anhydride derivative and the maleic acid copolymer represented by the general formulas (5) and (6) are preferable. R _D and R _E represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and * represents a binding site.

  As these compounds, commercially available compounds can be used. For example, epoxy resins manufactured by DIC (EPICLON series), maleic anhydride-modified resins manufactured by Nihon Unicar (Nack Ace GB-301), Kuraray Co., Ltd. Examples thereof include isobutylene / maleic anhydride copolymer resins (Isoban series) manufactured by the Company.

  These compounds exhibit an effect even with a low molecular weight or a high molecular weight. The addition amount of these compounds is preferably 0.1 to 10%, and more preferably 0.2 to 5%. By making the addition amount 0.1% or more, the effect of the present invention can be easily obtained. On the other hand, by making the addition amount 10% or less, the viscosity does not become too high, the emission from the inkjet head is stabilized, and the film after curing is obtained. Strength becomes good.

  Next, other components of the ink composition of the present invention will be described.

[Colorant]
When coloring the inkjet ink of this invention, it is preferable to use a pigment as a coloring agent. As the pigment, colorless inorganic pigments such as carbon black, titanium oxide, calcium carbonate, or colored organic pigments can be used. Examples of organic pigments include insoluble azo pigments such as toluidine red, toluidine maroon, Hansa yellow, benzidine yellow and pyrazolone red, soluble azo pigments such as ritole red, heliobordeaux, pigment scarlet, and permanent red 2B; alizarin, indanthrone, thio Derivatives from vat dyes such as indigo maroon; phthalocyanine organic pigments such as phthalocyanine blue and phthalocyanine green; quinacridone organic pigments such as quinacridone red and quinacridone magenta; perylene organic pigments such as perylene red and perylene scarlet; isoindolinone Isoindolinone organic pigments such as yellow and isoindolinone orange; Pyranthrone organic pigments such as pyranthrone red and pyranthrone orange; Thioindigo Machine pigments, condensed azo organic pigments, benzimidazolone organic pigments, quinophthalone organic pigments such as quinophthalone yellow; isoindoline organic pigments such as isoindoline yellow; other pigments such as flavanthron yellow, acylamide yellow, nickel Azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet and the like can be mentioned.

  Organic pigments are exemplified below by color index (CI) numbers.

C. I. Pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 109, 110, 117, 120, 125, 128, 129, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185,
C. I. Pigment Orange 16, 36, 43, 51, 55, 59, 61,
C. I. Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 177, 180, 192, 202, 206, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240,
C. I. Pigment violet 19, 23, 29, 30, 37, 40, 50,
C. I. Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64,
C. I. Pigment Green 7, 36,
C. I. Pigment brown 23, 25, 26,
Among the above pigments, quinacridone-based, phthalocyanine-based, benzimidazolone-based, isoindolinone-based, condensed azo-based, quinophthalone-based, and isoindoline-based organic pigments are preferable because of their excellent light resistance.

  The organic pigment is preferably fine particles having an average particle diameter in the ink of 10 to 150 nm as measured by laser scattering. When the average particle size of the pigment is less than 10 nm, the light resistance is lowered due to the small particle size, and when it exceeds 150 nm, it is difficult to maintain stable dispersion, and the precipitation of the pigment is likely to occur. Stability is lowered, and a problem that minute mist called satellite occurs. However, in the case of titanium oxide, the average particle diameter is 150 to 300 nm, preferably 180 to 250 nm, in order to provide whiteness and concealment.

  In addition, it is preferable that coarse particles are removed by sufficient dispersion or filtration so that the maximum particle size of the pigment in the ink does not exceed 1.0 μm. When coarse particles are present, the ejection stability tends to be lowered.

  The organic pigment can be refined by the following method. That is, a mixture composed of at least three components of an organic pigment, a water-soluble inorganic salt of 3 mass times or more of the organic pigment, and a water-soluble solvent is made into a clay, and is kneaded strongly with a kneader or the like to be refined, and then poured into water. Stir with a high speed mixer or the like to form a slurry. Next, filtration and washing of the slurry are repeated, and the water-soluble inorganic salt and the water-soluble solvent are removed by aqueous treatment. In the miniaturization step, a resin, a pigment dispersant and the like may be added.

  Examples of the water-soluble inorganic salt include sodium chloride and potassium chloride. These inorganic salts are used in the range of 3 to 20 times the mass of the organic pigment, but after the dispersion treatment, chlorine ions (halogen ions) are washed with water in order to achieve the halogen ion content defined in the present invention. Perform the operation to remove. If the amount of the inorganic salt is less than 3 times by mass, a treated pigment having a desired size cannot be obtained, and if it is more than 20 times by mass, the washing process in the subsequent step is enormous, Processing amount is reduced.

  The water-soluble solvent is not particularly limited as long as it is a solvent that can be used for making an appropriate clay state of an organic pigment and a water-soluble inorganic salt used as a crushing aid and performing sufficient crushing efficiently, and is soluble in water. However, since the temperature rises during kneading and the solvent easily evaporates, a high boiling point solvent having a boiling point of 120 to 250 ° C. is preferable from the viewpoint of safety. As water-soluble solvents, 2- (methoxymethoxy) ethanol, 2-butoxyethanol, 2- (i-pentyloxy) ethanol, 2- (hexyloxy) ethanol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether , Triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, low molecular weight Examples thereof include polypropylene glycol.

  In addition, in order to ensure the dispersion stability of the pigment, surface treatment by a known technique such as acidic treatment or basic treatment, synergist, various coupling agents in order to promote adsorption with the pigment dispersant on the surface thereof. Is preferable.

  In order to obtain a sufficient concentration and sufficient light resistance, the pigment is in the range of 1.5 to 8% by mass in the case of a color excluding white in the inkjet ink, and in the range of 10 to 30% by mass in the case of a white ink using titanium oxide. It is preferable that it is contained.

(Pigment dispersant)
Examples of the pigment dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a salt of a long chain polyaminoamide and a polar acid ester, a high molecular weight unsaturated acid ester, Polymer copolymer, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, polyoxyethylene alkyl phosphate ester, polyoxyethylene nonyl Examples thereof include phenyl ether, stearylamine acetate, and pigment derivatives.

  Specific examples include “Anti-Terra-U (polyaminoamide phosphate)”, “Anti-Terra-203 / 204 (high molecular weight polycarboxylate)” manufactured by BYK Chemie, “Disperbyk-101 (polyaminoamide phosphate) Salt (acid ester), 107 (hydroxyl group-containing carboxylic acid ester), 110 (copolymer containing acid group), 130 (polyamide), 161, 162, 163, 164, 165, 166, 170 (polymer copolymer) ) "," 400 "," Bykumen "(high molecular weight unsaturated acid ester)," BYK-P104, P105 (high molecular weight unsaturated acid polycarboxylic acid) "," P104S, 240S (high molecular weight unsaturated acid polycarboxylic acid) And silicone) ”,“ Lactimon (long chain amine and unsaturated acid polycarboxylic acid) Recone) "and the like.

  Further, “Efka CHEMICALS” “Efka 44, 46, 47, 48, 49, 54, 63, 64, 65, 66, 71, 701, 764, 766”, “Efka Polymer 100 (modified polyacrylate), 150 (fat) Group modified polymer), 400, 401, 402, 403, 450, 451, 452, 453 (modified polyacrylate), 745 (copper phthalocyanine)); “Floren TG-710 (urethane oligomer)” manufactured by Kyoei Chemical Co., Ltd. "Flonon SH-290, SP-1000", "Polyflow No. 50E, No. 300 (acrylic copolymer)"; "Disparon KS-860, 873SN, 874 (polymer dispersing agent) manufactured by Enomoto Kasei Co., Ltd. , # 2150 (aliphatic polyvalent carboxylic acid), # 7004 (polyether ester type) ”, etc. It is below.

  Furthermore, “Demol RN, N (Naphthalenesulfonic acid formalin condensate sodium salt), MS, C, SN-B (aromatic sulfonic acid formalin condensate sodium salt), EP”, “Homogenol L-18” manufactured by Kao Corporation. (Polycarboxylic acid type polymer) "," Emulgen 920, 930, 931, 935, 950, 985 (polyoxyethylene nonyl phenyl ether) "," Acetamine 24 (coconut amine acetate), 86 (stearyl amine acetate) "; “Solspers 5000 (phthalocyanine ammonium salt type), 13240, 13940 (polyesteramine type), 17000 (fatty acid amine type), 24000, 32000, 7000” manufactured by Zeneca Corporation; “Nikkor T106 (polyoxyethylene sorbitan) manufactured by Nikko Chemical Co., Ltd.” mono Rate), MYS-IEX (polyoxyethylene monostearate), Hexagline4-0 (hexaglyceryl ruthenate Huwei Rate) ", manufactured by Ajinomoto Fine-Techno Co., of AJISPER 821,822,824, and the like.

  These pigment dispersants are contained in an amount of 5 to 70% by mass, preferably 10 to 50% by mass, based on the pigment 100. If it is less than 5%, it may be difficult to obtain dispersion stability, and if it is more than 70%, ejection stability may be deteriorated.

  Furthermore, these pigment dispersants preferably have a solubility of 5% by mass or more with respect to the whole cationic polymerizable compound at 0 ° C. If the solubility is less than 5% by mass, when the ink is stored at a low temperature between about 0 ° C. and 10 ° C., undesired polymer gel or pigment soft agglomerates may occur, and the ink storage stability And discharge stability may deteriorate.

[Radical polymerization inhibitor]
In the active energy ray-curable inkjet ink composition or inkjet ink of the present invention, it is preferable to add a radical polymerization inhibitor from the viewpoint of storage stability. In the ink-jet ink of the present invention, radical polymerization may occur during storage due to radicals generated by the influence of heat or light. The use of a radical polymerization inhibitor in the active energy ray-curable inkjet ink composition or inkjet ink of the present invention has the effect of preventing radical polymerization that occurs during storage, but does not inhibit the curing of photocationic polymerization. This is a very preferable embodiment because it has the effect of enhancing only the storage stability of the ink over time without inhibiting the photocuring of the ink mainly composed of vinyl ether as in the present invention and having excellent curability.

  As radical polymerization inhibitors, phenolic hydroxyl group-containing compounds, methoquinone (hydroquinone monomethyl ether), hydroquinone, 4-methoxy-1-naphthol, hindered amine antioxidants, 1,1-diphenyl-2-picrylhydrazyl free radicals , N-oxide compounds, piperidine 1-oxyl free radical compounds, pyrrolidine 1-oxyl free radical compounds, N-nitrosophenylhydroxylamines, nitrogen-containing heterocyclic mercapto compounds, thioether antioxidants, hindered phenols Antioxidants, ascorbic acids, zinc sulfate, thiocyanates, thiourea derivatives, various sugars, phosphate antioxidants, nitrites, sulfites, thiosulfates, hydroxylamine derivatives, dicyandiamide and polyamines Examples thereof include polycondensates of lucylene polyamine, phenothiazine, and the like.

  Specific examples of the radical polymerization inhibitor include the following compounds.

  Examples of the phenolic compound include the following compounds: phenol, alkylphenol, such as o-, m- or p-cresol (methylphenol), 2-t-butyl-4-methylphenol, 6-t-butyl. -2,4-dimethylphenol, 2,6-di-t-butyl-4-methylphenol, 2-t-butylphenol, 4-t-butylphenol, 2,4-di-t-butylphenol, 2-methyl-4 -T-butylphenol, 4-t-butyl-2,6-dimethylphenol, or 2,2'-methylene-bis- (6-t-butyl-methylphenol), 4,4'-oxydiphenyl, 3,4 -Methylenedioxydiphenol (sesame oil), 3,4-dimethylphenol, benzcatechin (1,2-dihydroxybenzol), 2- 1'-methylcyclohexyl-1'-yl) -4,6-dimethylphenol, 2- or 4- (1'-phenyleth-1'-yl) phenol, 2-t-butyl-6-methylphenol, 2 , 4,6-Tris-t-butylphenol, 2,6-di-t-butylphenol, nonylphenol [CAS-Nr. 11066-49-2], octylphenol [CAS-Nr. 140-66-9], 2,6-dimethylphenol, bisphenol A, bisphenol B, bisphenol C, bisphenol F, bisphenol S, 3,3 ', 5,5'-tetrabromobisphenol A, 2,6-di- t-butyl-p-cresol, BASF Aktiengesellschaft, Kolesin, 3,5-di-t-butyl-4-hydroxybenzoic acid methyl ester, 4-t-butylbenzcatechin, 2-hydroxybenzyl alcohol, 2- Methoxy-4-methylphenol, 2,3,6-trimethylphenol, 2,4,5-trimethylphenol, 2,4,6-trimethylphenol, 2-isopropylphenol, 4-isopropylphenol, 6-isopropyl-m- Cresol, n-oct Decyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1, 3,5-trimethyl-2,4,6-tris- (3,5-di-tert-butyl-4-hydroxybenzyl) benzol, 1,3,5-tris- (3,5-di-tert-butyl -4-hydroxybenzyl) isocyanurate, 1,3,5-tris- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl-isocyanurate, 1,3,5-tris- (2 , 6-Dimethyl-3-hydroxy-4-t-butylbenzyl) isocyanurate or pentaerythrit-tetrakis- [β- (3,5-di-t-butyl-4-hydroxyphenyl) propione 2,6-di-t-butyl-4-dimethylaminomethylphenol, 6-s-butyl-2,4-dinitrophenol, Irganox 565, 1010, 1076, 1141, Firma Ciba Specialiaetenchemie, 1192, 1222 and 1425, 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid octadecyl ester. 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid hexadecyl ester, 3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid Octyl ester, 3-thia-1,5-pentanediol-bis- [3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate], 4,8-dioxa-1,11-undecanediol -Bis- [3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate], 4,8-dioxa-1,11-undecandiol-bis-[(3'-t-butyl-4 '-Hydroxy-5'-methylphenyl) propionate], 1,9-nonanediol-bis-[(3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] 1,7-heptanediamine-bis [3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionic acid amide], 1,1-methanediamine-bis [3- (3 ′, 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid amide], 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionic acid hydrazide, 3- (3' , 5'-dimethyl-4'-hydroxyphenyl) propionic hydrazide, bis- (3-tert-butyl-5-ethyl-2-hydroxyphen-1-yl) methane, bis- (3,5-di-t -Butyl-4-hydroxyphen-1-yl) methane, bis- [3- (1'-methylcyclohex-1'-yl) -5-methyl-2-hydroxyphen-1-yl] methane, bis- ( 3-t-butyl- -Hydroxy-5-methylphen-1-yl) methane, 1,1-bis- (5-tert-butyl-4-hydroxy-2-methylphen-1-yl) ethane, bis- (5-tert-butyl-4) -Hydroxy-2-methylphen-1-yl) sulfide, bis- (3-tert-butyl-2-hydroxy-5-methylphen-1-yl) sulfide, 1,1-bis- (3,4-dimethyl-2) -Hydroxyphen-1-yl) -2-methylpropane, 1,1-bis- (5-tert-butyl-3-methyl-2-hydroxyphen-1-yl) butane, 1,3,5-tris- [1 '-(3 ", 5" -di-t-butyl-4 "-hydroxyphen-1" -yl) methy-1'-yl] -2,4,6-trimethylbenzol, 1,1,4 -Tris- (5'-t-butyl-4'-hydro Xyl-2'-methylphen-1'-yl) butane and t-butylcatechol, and aminophenols such as p-aminophenol, nitrosophenols such as p-nitrosophenol, p-nitroso-o-cresol, alkoxyphenols For example, 2-methoxyphenol (guaiacol, benzcatechin monomethyl ether), 2-ethoxyphenol, 2-isopropoxyphenol, 4-methoxyphenol (hydroquinone monomethyl ether), mono- or di-t-butyl-4-methoxyphenol 3,5-di-t-butyl-4-hydroxyanisole, 3-hydroxy-4-methoxybenzyl alcohol, 2,5-dimethoxy-4-hydroxybenzyl alcohol (syringa alcohol), 4-hydroxy-3-me Xylbenzaldehyde (vanillin), 4-hydroxy-3-ethoxybenzaldehyde (ethylvanillin), 3-hydroxy-4-methoxybenzaldehyde (isovanillin), 1-((4-hydroxy-3-methoxyphenyl) ethanone (acetovanillin), Eugenol, dihydroeugenol, isoeugenol, tocopherol, for example α-, β-, γ-, δ- and ε-tocopherol, tocol, α-tocopherol hydroquinone, and 2,3-dihydro-2,2-dimethyl-7- Hydroxybenzofuran (2,2-dimethyl-7-hydroxycoumaran).

  Examples of quinone and hydroquinone include hydroquinone or hydroquinone monomethyl ether (4-methoxyphenol), methylhydroquinone, 2,5-di-t-butylhydroquinone, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, Trimethylhydroquinone 4-methylbenzcatechin, t-butylhydroquinone, 3-methylbenzcatechin, benzoquinone, 2-methyl-p-hydroquinone, 2,3-dimethylhydroquinone, trimethylhydroquinone, t-butylhydroquinone, 4-ethoxyphenol, 4 -Butoxyphenol, hydroquinone monobenzyl ether, p-phenoxyphenol, 2-methylhydroquinone, tetramethyl-p-benzoquinone, diethyl-1,4-cyclohexanedione-2,5- Carboxylate, phenyl-p-benzoquinone, 2,5-dimethyl-3-benzyl-p-benzoquinone, 2-isopropyl-5-methyl-p-benzoquinone (thymoquinone), 2,6-diisopropyl-p-benzoquinone, 2, 5-dimethyl-3-hydroxy-p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, envelopen, tetrahydroxy-p-benzoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2-amino-5-methyl -P-benzoquinone, 2,5-bisphenylamino-1,4-benzoquinone, 5,8-dihydroxy-1,4-naphthoquinone, 2-anilino-1,4-naphthoquinone, anthraquinone, N, N-dimethylindoaniline N, N-diphenyl-p-benzoquinone diimine, 1,4-benzox Dioxime, cerlignon, 3,3'-di-t-butyl-5,5'-dimethyldiphenoquinone, p-rosoleic acid (orine), 2,6-di-t-butyl-4-benzylidene-benzoquinone, 2 , 5-di-tert-butyl-amylhydroquinone is preferred.

  Examples of N-oxyl (a compound having a nitroxyl- or N-oxyl-group and at least one> NO-group) include, for example, 4-hydroxy-2,2,6,6-tetramethyl-piperidine. -N-oxyl, 4-oxo-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-methoxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, 4-acetoxy -2,2,6,6-tetramethyl-piperidine-N-oxyl, 2,2,6,6-tetramethyl-piperidine-N-oxyl, BASF Aktiengesellschaft, Uvinul 4040P, 4,4 ', 4 "-Tris- (2,2,6,6-tetramethyl-piperidine-N-oxyl) phosphite, 3-oxo-2,2,5,5-te Lamethyl-pyrrolidine-N-oxyl, 1-oxyl-2,2,6,6-tetramethyl-4-methoxypiperidine, 1-oxyl-2,2,6,6-tetramethyl-4-trimethylsilyloxypiperidine, 1 -Oxyl-2,2,6,6-tetramethylpiperidin-4-yl-2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-sebacate, 1- Oxyl-2,2,6,6-tetramethylpiperidin-4-yl-stearate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-benzoate, 1-oxyl-2,2 , 6,6-Tetramethylpiperidin-4-yl- (4-t-butyl) benzoate, bis- (1-oxyl-2,2,6,6-tetramethylpiperidine- 4-yl) succinate, bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate, 1,10-decanedioic acid-bis- (1-oxyl-2,2,6) , 6-Tetramethylpiperidin-4-yl) ester, bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) n-butylmalonate, bis- (1-oxyl-2) , 2,6,6-Tetramethylpiperidin-4-yl) phthalate, bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) isophthalate, bis- (1-oxyl- 2,2,6,6-tetramethylpiperidin-4-yl) terephthalate, bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) hexahydroterephthalate, , N'-bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipinamide, N- (1-oxyl-2,2,6,6-tetramethylpiperidine-4 -Yl) caprolactam, N- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) dodecylsuccinimide, 2,4,6-tris- [N-butyl-N- (1-oxyl) -2,2,6,6-tetramethylpiperidin-4-yl] triazine, N, N'-bis- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) -N, N'-bis-formyl-1,6-diaminohexane, 4,4'-ethylene-bis- (1-oxyl-2,2,6,6-tetramethylpiperazin-3-one) are preferred.

  As aromatic amine or phenylenediamine, for example, N, N-diphenylamine, N-nitroso-diphenylamine, nitrosodiethylaniline, p-phenylenediamine, N, N'-dialkyl-p-phenylenediamine (in this case, the alkyl groups are the same) Or may be different, each independent of one another, containing 1 to 4 carbon atoms and may be linear or molecular)), for example, N, N′-di-iso-butyl-p-phenylenediamine N, N'-di-iso-propyl-p-phenylenediamine, Irmax 5057 from Firma Ciba Specialiaetenchemie, N-phenyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N-isopropyl- N-phenyl-p-phenylenediamine, N, N'-di-s-butyl-p-phenylenediamine (Kerobit BPD from BASF Aktiengesellschaft), N-phenyl-N'-isopropyl-p-phenylenediamine (Vulkanox 4010 from Bayer AG) N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, N-phenyl-2-naphthylamine, iminodibenzyl, N, N′-diphenylbenzidine, N-phenyltetraaniline, acridone, 3-hydroxydiphenylamine and 4-hydroxydiphenylamine are preferred.

  Examples of imines include methylethylimine, (2-hydroxyphenyl) benzoquinoneimine, (2-hydroxyphenyl) benzophenoneimine, N, N-dimethylindoaniline, and thionine (7-amino-3-imino-3H-phenothiazine). , Methylene violet (7-dimethylamino-3-phenothiazinone).

  Examples of sulfonamides that are effective as radical polymerization inhibitors include N-methyl-4-toluolsulfonamide, Nt-butyl-4-toluolsulfonamide, Nt-butyl-N-oxyl-4-toluene. Allsulfonamide, N, N′-bis (4-sulfanilamide) piperidine, 3-{[5- (4-aminobenzoyl) -2,4-dimethylbenzoylsulfonyl] ethylamino} -4-methylbenzolsulfonic acid is there.

  Examples of oximes effective as radical polymerization inhibitors include aldoxime, ketoxime or amidoxime, preferably diethyl ketoxime, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime, benzaldehyde oxime, benzyldioxime, dimethylglyoxime, 2-pyridine aldoxime, Salicylaldoxime, phenyl-2-pyridylketoxime, 1,4-benzoquinone dioxime, 2,3-butanedione dioxime, 2,3-butanedione monooxime, 9-fluorenone oxime, 4-t-butyl-cyclohexanone Oxime, N-ethoxy-acetimidic acid ethyl ester, 2,4-dimethyl-3-pentanone oxime, cyclododecanone oxime, 4-heptanone oxime and di-2-furanylethanedione It may be an oxime or other aliphatic or aromatic oxime or alkyl transfer agent such as its reaction product with an alkyl halide, -triflate, -sulfonate, -tosylate, -carbonate, -sulfate, -phosphate, etc. .

  Examples of the hydroxylamine include N, N-diethylhydroxylamine and compounds described in PCT / EP / 03/03139 international patent application.

  As the urea derivative, for example, urea or thiourea is suitable.

  The phosphorus-containing compound is, for example, triphenylphosphine, triphenylphosphite, hypophosphorous acid, trinonylphosphite, triethylphosphite or diphenylisopropylphosphine.

  Suitable sulfur-containing compounds are, for example, diphenyl sulfide, phenothiazine and sulfur-containing natural substances such as cysteine.

  Complexing agents based on tetraazaannulene (TAA) are described, for example, in Chem. Soc. Rev. 1998, 27, 105-115, for example, dibenzotetraaza [14] ring and porphyrin.

  In addition, each metal salt (copper, manganese, cerium, nickel, chromium, etc.) such as carbonic acid, chloride, dithiocarbamic acid, sulfuric acid, salicylic acid, acetic acid, stearic acid, and ethylhexanoic acid can be exemplified.

  Macromol. Rapid Commun. , 28, 1929 (2007), the N-oxyl free radical compound having a vinyl ether functional group has a structure having both a polymerizable function and a radical scavenging function in the same molecule. From the viewpoint of curability and ink storage stability, It is preferable to add to the ink of the present invention. In addition, the polymer obtained by polymerizing this N-oxyl free radical compound having a vinyl ether functional group is a polymer having a structure having a free radical in the side chain, and is cured such as solvent resistance, scratch resistance and weather resistance. From the viewpoint of film physical properties and ink storage stability, it is preferably added to the ink of the present invention.

  The addition amount of the radical polymerization inhibitor is preferably 1.0 to 5000 μg / g ink, and more preferably 10 to 2000 μg / g ink. If it is 1.0 μg / g or more, desired storage stability can be obtained, ink thickening and liquid repellency with respect to the ink jet nozzle can be obtained, and this is preferable from the viewpoint of ejection stability. Moreover, if it is 5000 microgram / g ink or less, the high generation sensitivity can be maintained, without impairing the acid generation efficiency of a polymerization initiator.

[Other additives]
In the active energy ray-curable ink-jet ink composition or ink-jet ink of the present invention, in addition to the above description, emission stability, print head and ink packaging container compatibility, storage stability, image storage stability, etc. Various known additives such as surfactants, lubricants, fillers, antifoaming agents, gelling agents, thickeners, specific resistance adjusting agents, film forming agents, ultraviolet absorbers depending on the purpose of improving the performance of An agent, an antioxidant, a discoloration inhibitor, an antibacterial agent, a rust inhibitor, and the like can be appropriately selected and used.

  Further, if necessary, a small amount of solvent such as ester solvent, ether solvent, ether ester solvent, ketone solvent, aromatic hydrocarbon solvent, nitrogen-containing organic solvent may be added.

  Specific examples include dimethyl sulfoxide, diethyl sulfoxide, methyl ethyl sulfoxide, diphenyl sulfoxide, tetraethylene sulfoxide, dimethyl sulfone, methyl ethyl sulfone, methyl-isopropyl sulfone, methyl-hydroxyethyl sulfone, sulfolane, or N-methyl-2- Pyrrolidone, 2-pyrrolidone, β-lactam, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone , Γ-butyrolactone, γ-valerolactone, isophorone, cyclohexanone, propylene carbonate, anisole, methyl ethyl ketone, acetone, ethyl lactate, butyl lactate, dioxane, ethyl acetate, butyrate , Diethylene glycol dimethyl ether, dibasic ester, methoxybutyl acetate, etc., can be mentioned. When these are added to the ink in an amount of 1.5 to 30%, preferably 1.5 to 15%, adhesion to a resin recording medium such as polyvinyl chloride is improved.

  Other specific examples include alkylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, and alkylenes such as ethylene glycol dibutyl ether and tetraethylene glycol dimethyl ether. Examples include glycol dialkyl ethers, alkylene glycol monoalkyl ether acetates such as ethylene glycol monobutyl ether acetate, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol diacetate, and propylene glycol diacetate.

  Examples of the surfactant that can be used in the active energy ray-curable inkjet ink composition or inkjet ink of the present invention include anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, Nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic such as alkylamine salts and quaternary ammonium salts Surfactants, silicone-based and fluorine-based surfactants are exemplified, and silicone-based or fluorine-based surfactants are particularly preferable.

  By adding a silicone-based or fluorine-based surfactant, it is possible to further suppress ink mixing on recording media made of various hydrophobic resins such as vinyl chloride sheets and recording media that absorb slowly such as printing paper. And high-quality printed images can be obtained. The surfactant is particularly preferably used in combination with the low surface tension water-soluble organic solvent.

  The silicone surfactant is preferably a polyether-modified polysiloxane compound. For example, KF-351A, KF-642, X-22-4272 manufactured by Shin-Etsu Chemical Co., Ltd., BYK307, BYK345, BYK347 manufactured by Big Chemie, BYK348, TSF4452 manufactured by Toshiba Silicone Co., etc. can be mentioned.

  The fluorine-based surfactant means a compound in which a part or all of the surfactant is substituted with fluorine in place of hydrogen bonded to carbon of the hydrophobic group of a normal surfactant. Of these, those having a perfluoroalkyl group in the molecule are preferred.

  Among the fluorosurfactants, some are from DIC under the trade name Megafac F and from Asahi Glass under the trade name Surflon, Minnesota Mining and Manufacturing Company Under the trade name Fluorad FC from the company, under the trade name Monflor from Imperial Chemical Industry, and under the trade name Zonyls from EI Dupont Nemeras & Company, Also, the product name of Licobet VPF is available from Farbeberke-Hoechst and the name of footage is available from Neos.

  The addition amount of the surfactant is preferably 0.1% by mass or more and less than 2.0% by mass with respect to the total mass of the ink.

  If the surface tension of the ink is 15 mN / m or more, the area around the nozzles of the inkjet head does not get wet and the discharge capacity does not decrease. This is preferable because the recording medium made of paper or resin is well wetted and does not cause whitening.

[Ink properties]
The physical properties of the inkjet ink of the present invention preferably have the same physical properties as those of a normal active energy ray-curable inkjet ink. That is, the viscosity is 2 to 50 mPa · s at 25 ° C., the share rate dependency is as small as possible, the surface tension is in the range of 22 to 35 mN / m at 25 ° C., and when a pigment is used as the colorant, It is preferable that there is no gel-like substance having an average particle size exceeding 1.0 μm other than the particles, the conductivity is 10 μS / cm or less, and the ink is free from electrical corrosion inside the head. . In the continuous type, it is necessary to adjust the electric conductivity by the electrolyte. In this case, it is necessary to adjust the electric conductivity to 0.5 mS / cm or more.

  In addition, as a physical property of the ink-jet ink of the present invention, a more preferable form is that the calorific value per unit mass is obtained when the DSC measurement of the ink is performed in the range of 25 ° C. to −25 ° C. at a rate of 5 ° C. per minute. The exothermic peak of 10 mJ / mg or more is not exhibited. By selecting a material according to the configuration of the present invention, it is possible to suppress heat generation of a certain amount or more in DSC measurement. By adopting such a configuration, even when the ink is stored at a low temperature, the generation of gel and the generation of precipitates can be suppressed.

[Ink preparation method]
The ink-jet ink of the present invention comprises an active energy ray-curable compound, a polymerizable compound, a photopolymerization initiator, a pigment dispersant as a colorant, and a pigment as a colorant. It is manufactured by well dispersing using a disperser. It is preferable to prepare a concentrated solution having a high pigment concentration in advance and dilute with a polymerizable compound. Sufficient dispersion is possible even with dispersion by ordinary dispersers. Therefore, excessive dispersion energy is not applied and a large amount of dispersion time is not required, so it is difficult to cause deterioration during dispersion of ink components, and stability. Can be prepared. The prepared ink is preferably filtered through a filter having a pore diameter of 3 μm or less, and more preferably 1 μm or less.

"recoding media"
As a recording medium used in the inkjet recording method of the present invention, a wide range of conventional synthetic resins used in various applications are all targeted, and specifically, for example, polyester, polyvinyl chloride, polyethylene, polyurethane, polypropylene , Acrylic resin, polycarbonate, polystyrene, acrylonitrile-butadiene-styrene copolymer, polyethylene terephthalate, polybutadiene terephthalate and the like, and the thickness and shape of these synthetic resin substrates are not limited at all. In addition, metals, glass, printing paper, etc. can be used.

  In addition, as a recording medium (so-called rigid base material) having a resin base material that does not contain a plasticizer or a non-absorbing inorganic base material as a constituent element (so-called rigid base material), one type of base material can be used alone with the following various base materials as constituent elements. Or in combination of multiple types of substrates. Examples of the resin base material containing no plasticizer used in the present invention include ABS resin, polycarbonate (PC) resin, polyacetal (POM) resin, polyamide (PA) resin, polyethylene terephthalate (PET) resin, and polyimide (PI). Examples thereof include a resin, an acrylic resin, a polyethylene (PE) resin, a polypropylene (PP) resin, and a hard polyvinyl chloride (PVC) resin that does not contain a plasticizer.

  These resins are characterized by not containing a plasticizer, but there are no particular restrictions on other properties such as thickness, shape, color, softening temperature, and hardness.

  The recording medium used in the present invention is preferably ABS resin, PET resin, PC resin, POM resin, PA resin, PI resin, hard PVC resin containing no plasticizer, acrylic resin, PE resin, or PP resin. More preferred are ABS resin, PET resin, PC resin, PA resin, hard PVC resin not containing plasticizer, and acrylic resin.

  Moreover, as a non-absorbing inorganic base material used for this invention, a metal plate, such as a glass plate, iron, and aluminum, a ceramic plate etc. are mentioned, for example. These inorganic substrates are characterized by not having an ink-absorbing layer on the surface. These non-absorbing inorganic base materials are not particularly limited with respect to other properties such as thickness, shape, color, softening temperature, and hardness.

<Inject recording method>
The ink-jet head used in the in-jet recording method of the present invention for ejecting the ink-jet ink of the present invention to form an image may be an on-demand system or a continuous system. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, thermal ink jet) Any ejection method such as a mold, a bubble jet (registered trademark) mold, or the like may be used.

  The ink jet recording method of the present invention is a recording method in which the active energy ray-curable ink jet ink of the present invention is ejected onto a recording medium from an ink jet nozzle and then irradiated with active energy rays such as ultraviolet rays to cure the ink. .

(Activation energy ray irradiation conditions after ink landing)
In the ink jet recording method of the present invention, the active energy ray is preferably irradiated for 0.001 second to 1.0 second after ink landing, more preferably 0.001 second. ~ 0.5 seconds.

  In order to form a high-definition image, it is preferable that the irradiation timing is as early as possible.

  The irradiation method of an active energy ray is not specifically limited, For example, it can carry out with the following method.

  A light source is provided on both sides of the head unit described in JP-A-60-132767, and the head and the light source are scanned by a shuttle method. Irradiation is performed after a certain period of time after ink landing, and is not accompanied by driving. A method of completing curing with another light source, a method using an optical fiber as described in US Pat. No. 6,145,979, or a collimated light source is applied to a mirror surface provided on the side of the head unit, and the recording unit is irradiated with ultraviolet rays. The method of doing can be mentioned.

  Any of these irradiation methods can be used in the inkjet recording method of the present invention.

  Also, the irradiation of active energy rays is divided into two stages. First, the active energy rays are irradiated by the above-described method within 0.001 to 2.0 seconds after ink landing, and after the completion of all printing, the active energy rays are further irradiated. The method of irradiating is also a preferred embodiment.

  By dividing the irradiation of the active energy ray into two stages, it is possible to further suppress the shrinkage of the recording material that occurs during ink curing.

(Total ink film thickness after ink landing)
In the ink jet recording method of the present invention, the total ink film thickness after ink has landed on the recording medium and cured by irradiation with active energy rays is 2 to 20 μm. It is preferable from the aspect of the texture change.

  Here, “total ink film thickness” means the maximum value of the film thickness of the ink drawn on the recording medium, and even for a single color, other two color layers (secondary colors), three color layers, Even when recording is performed using a four-color overlapping (white ink base) inkjet recording method, the meaning of the total ink film thickness is the same.

(Ink heating and ejection conditions)
In the inkjet recording method of the present invention, it is preferable from the viewpoint of ejection stability that the active energy ray-curable inkjet ink is heated and irradiated with the active energy ray.

  The temperature for heating is preferably 35 to 100 ° C., and more preferably in view of discharge stability and irradiation with active energy rays while being kept at 35 to 80 ° C.

  There is no particular limitation on the method of heating and keeping the ink-jet ink at a predetermined temperature.For example, an ink supply system such as an ink tank constituting a head carriage, a supply pipe, a front chamber ink tank immediately before the head, a pipe with a filter, There is a method in which a piezo head or the like is insulated and heated to a predetermined temperature by a panel heater, a ribbon heater, warm water or the like.

  The control range of the ink temperature is preferably set temperature ± 5 ° C., more preferably set temperature ± 2 ° C., and particularly preferably set temperature ± 1 ° C. from the viewpoint of ejection stability.

  The amount of liquid droplets ejected from each nozzle is preferably 2 to 20 pl from the viewpoint of recording speed and image quality.

  Next, an ink jet recording apparatus (hereinafter simply referred to as a recording apparatus) that can be used in the ink jet recording method of the present invention will be described.

  Hereinafter, the recording apparatus will be described with reference to the drawings as appropriate.

  FIG. 1 is a front view showing a configuration of a main part of the recording apparatus.

  The recording apparatus 1 includes a head carriage 2, a recording head 3, an irradiation unit 4, a platen unit 5, and the like.

  In the recording apparatus 1, the platen unit 5 is installed under the recording medium P.

  The platen unit 5 has a function of absorbing ultraviolet rays, and absorbs excess ultraviolet rays that have passed through the recording medium P.

  As a result, a high-definition image can be reproduced very stably.

  The recording medium P is guided by the guide member 6 and moves from the near side to the far side in FIG. 1 by the operation of the conveying means (not shown). A head scanning unit (not shown) scans the recording head 3 held by the head carriage 2 by reciprocating the head carriage 2 in the Y direction in FIG.

  The head carriage 2 is installed on the upper side of the recording medium P, and accommodates a plurality of recording heads 3 to be described later according to the number of colors used for image printing on the recording medium P, with the discharge ports arranged on the lower side.

  The head carriage 2 is installed with respect to the main body of the recording apparatus 1 in such a manner that it can reciprocate in the Y direction in FIG. 1, and reciprocates in the Y direction in FIG. 1 by driving the head scanning means.

  In FIG. 1, the head carriage 2 is white (W), yellow (Y), magenta (M), cyan (C), black (K), light yellow (Ly), light magenta (Lm), and light cyan (Lc). In the drawing, the recording head 3 for light black (Lk) and white (W) is drawn. However, in practice, the number of colors of the recording head 3 stored in the head carriage 2 is appropriately determined. Is.

  The recording head 3 is operated by a discharge means (not shown) provided with a plurality of active energy ray curable inkjet inks (for example, UV curable ink) supplied by an ink supply means (not shown). The ink is discharged from the discharge port toward the recording medium P.

  The recording head 3 is a certain area (landing possible area) in the recording medium P during the scanning in which the recording head 3 moves from one end of the recording medium P to the other end of the recording medium P in the Y direction in FIG. On the other hand, UV ink is ejected as ink droplets, and ink droplets are landed on the landable area.

  The above-described scanning is performed as many times as necessary, and the active energy ray-curable inkjet ink is ejected toward one landable area. Then, the recording medium P is appropriately moved from the front to the back in FIG. While performing scanning by the head scanning means, the recording head 3 discharges UV ink to the next landable area adjacent to the rearward direction in FIG.

  An assembly of active energy ray-curable inkjet ink droplets on the recording medium P by repeating the above operation and ejecting the recording head 3 or the active energy ray-curable inkjet ink in conjunction with the head scanning means and the conveying means. Is formed.

  The irradiation unit 4 includes, for example, an ultraviolet lamp that emits ultraviolet light in a specific wavelength region with stable exposure energy and a filter that transmits ultraviolet light of a specific wavelength.

  Here, as the ultraviolet lamp, a mercury lamp, a metal halide lamp, an excimer laser, an ultraviolet laser, a cold cathode tube, a hot cathode tube, a black light, an LED (light emitting diode) and the like can be applied. A cathode tube, a hot cathode tube, a mercury lamp or black light is preferred.

  In particular, a low-pressure mercury lamp, a hot cathode tube, a cold cathode tube, and a germicidal lamp that emit ultraviolet light having a wavelength of 254 nm are preferable because they can prevent bleeding and control the dot diameter efficiently.

  By using black light as the radiation source of the irradiation means 4, the irradiation means 4 for curing the UV ink can be produced at low cost.

  The irradiating means 4 has substantially the same shape as the maximum one that can be set by the recording apparatus (UV inkjet printer) 1 among the landable areas in which the recording head 3 ejects UV ink by one scan driven by the head scanning means. , Having a shape larger than the landable area.

  The irradiation means 4 is fixed on both sides of the head carriage 2 so as to be substantially parallel to the recording medium P.

  As described above, as a means for adjusting the illuminance of the ink discharge portion, not only the entire recording head 3 is shielded, but in addition, the ink discharge of the recording head 3 is determined from the distance h1 between the irradiation means 4 and the recording medium P. It is effective to increase the distance h2 between the portion 31 and the recording medium P (h1 <h2) or to increase the distance d between the recording head 3 and the irradiation means 4 (d is increased).

  Further, it is more preferable that a bellows structure 7 is provided between the recording head 3 and the irradiation means 4.

  Here, the wavelength of the ultraviolet rays irradiated by the irradiation unit 4 can be changed as appropriate by exchanging the ultraviolet lamp or the filter provided in the irradiation unit 4.

  FIG. 2 is a top view illustrating another example of the configuration of the main part of the ink jet recording apparatus.

  The ink jet recording apparatus shown in FIG. 2 is called a line head system, and a plurality of ink jet recording heads 3 of each color are fixedly arranged on the head carriage 2 so as to cover the entire width of the recording medium P. ing.

  On the other hand, on the downstream side of the head carriage 2, that is, the rear portion of the head carriage 2 in the direction in which the recording medium P is conveyed, the entire width of the recording medium P is also covered so as to cover the entire ink printing surface. Arranged irradiation means 4 are provided.

  As the ultraviolet lamp used in the illuminating means 4, the same one as described in FIG. 1 can be used.

  In this line head system, the head carriage 2 and the irradiation means 4 are fixed, and only the recording medium P is conveyed, and ink ejection and curing are performed to form an image.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

《Synthesis of maleimide compound》
[Synthesis of Exemplified Compound M-5]
In a 300 ml eggplant type flask equipped with a stirrer, a decompression device and a trap, 33.8 g of 2-maleimido-2-methylacetic acid, 10.2 g of diethylene glycol, p-toluenesulfone synthesized by the method described in Patent Document “No. 3599160” Acid monohydrate (4.47 g), 2,6-tert-butyl-p-cresol (0.35 g) and toluene (20 ml) were sequentially added, and the reaction temperature was 80 ° C. while azeotropically distilling off the water and toluene produced under reduced pressure. The reaction was terminated by stirring for 5 hours under the conditions described above. The reaction solution was cooled to room temperature, dissolved in 300 ml of ethyl acetate, and washed 3 times with 100 ml of saturated aqueous sodium hydrogen carbonate solution and once with 100 ml of saturated brine. The organic layer was dried over magnesium sulfate and concentrated to obtain 24.7 g of exemplary compound M-5. This material is a liquid at room temperature. Moreover, e value of the maleimide which is a polymeric compound containing the same structure as the unsaturated bond part which exemplary compound M-5 has is 2.86.

As a result of analyzing the synthesized exemplary compound M-5 using NMR,
¹ H NMR (400 MHz, CDCl ₃ ):
6.75 (s, 4H, -CH = CH-), 4.82 (q, 2H, N-CH-),
4.20-4.32 (m, 4H, - ( C = O) -O-CH 2 -),
_{3.58-3.67 (m, 4H, -CH 2} -O-),
_{1.59 (d, 6H, -CH 3} ) and,
¹³ C NMR (100 MHz, CDCl ₃ ):
169.7 [N- (C = O)], 169.5 [-(C = O) -O-],
134.3 (—CH═CH—), 68.7 [— (C═O) —O—CH ₂ —],
64.6 (—CH ₂ —O—), 47.4 (—CH—), 15.1 (—CH ₃ )
It was confirmed that.

[Synthesis of Exemplified Compound M-20]
N-β-oxy-n-propyl synthesized in a 300 ml eggplant type flask equipped with a stirrer, a decompression device and a trap according to the method described in the literature “Organic Synthetic Chemistry, Vol. 23, No. 2 (1965)” 5.0 g of maleimide, 2.82 g of azelaic acid, 0.7 g of p-toluenesulfonic acid monohydrate, 0.05 g of 2,6-tert-butyl-p-cresol and 20 ml of toluene are sequentially charged and produced under reduced pressure. While azeotropically distilling off water and toluene, the reaction was terminated by stirring for 12 hours at a reaction temperature of 80 ° C. The reaction solution was cooled to room temperature, dissolved in 300 ml of ethyl acetate, and washed 3 times with 100 ml of saturated aqueous sodium hydrogen carbonate solution and once with 100 ml of saturated brine. The organic layer was dried over magnesium sulfate and concentrated to obtain 3.2 g of exemplary compound M-20. This material is a liquid at room temperature. Moreover, e value of the maleimide which is a polymeric compound containing the same structure as the unsaturated bond part which exemplary compound M-20 has is 2.86.

As a result of analyzing the synthesized exemplary compound M-20 using NMR,
¹ H NMR (400 MHz, CDCl ₃ ):
6.74 (s, 4H, -CH = CH-),
5.11-5.15 (m, 2H,-(C = O) -O-CH-),
3.64-3.68 (m, 4H, N—CH ₂ —),
2.23 (t, 4H, -O- ( C = O) -CH 2 -),
1.55 (brs, 4H, —CH ₂ —), 1.24 to 1.27 (m, 6H, —CH ₂ —),
_{1.24 (d, 6H, -CH 3} ) and,
¹³ C NMR (100 MHz, CDCl ₃ ):
173.1 [— (C═O) —O—], 170.4 [N— (C═O)],
134.0 (—CH═CH—), 67.9 [— (C═O) —O—CH—],
41.8 (—N—CH ₂ —), 34.1 [—O— (C═O) —CH ₂ —],
_{28.7 (2C) (- CH 2} -), 24.5 (-CH 2 -),
17.5 _(-CH 3),
It was confirmed that.

[Synthesis of Exemplified Compound M-3]
Synthesis of Exemplified Compound M-5 was performed under the same conditions except that 15.4 g of 1,9-nonanediol was used instead of 10.2 g of diethylene glycol. Obtained. This material is a liquid at room temperature. Moreover, e value of the maleimide which is a polymeric compound containing the same structure as the unsaturated bond part which exemplary compound M-3 has is 2.86.

As a result of analyzing the synthesized exemplary compound M-3 using NMR,
¹ H NMR (400 MHz, CDCl ₃ ):
6.74 (s, 4H, -CH = CH-), 4.78 (q, 2H, N-CH-),
4.08-4.18 (m, 4H, - ( C = O) -O-CH 2 -),
_{1.58-1.65 (m, 10H, -CH 2} -, - CH 3),
_{1.24-1.28 (m, 10H, -CH 2} -) and,
¹³ C NMR (100 MHz, CDCl ₃ ):
169.8 [N- (C = O)], 169.6 [-(C = O) -O-],
134.3 (—CH═CH—), 65.8 [— (C═O) —O—CH ₂ —],
47.5 (N—CH—), 29.2 (—CH ₂ —), 28.9 (—CH ₂ —),
_{28.3 (-CH 2 -), 25.6} (-CH 2 -), 15.1 (-CH 3)
It was confirmed that.

[Synthesis of Maleimide Compounds A to C]
Maleimide compound A, maleimide compound B, and maleimide compound C were synthesized according to the methods described in JP-A-11-124403 and JP-A-2003-213171.

  Specific structures of the synthesized maleimide compounds A to C are shown below.

Example 1
[Preparation of Pigment Dispersion 1]
As a magenta pigment, C.I. I. Pigment Red 122 (6.0 g), Addispar PB822 (manufactured by Ajinomoto Finetech Co., Ltd.) as a pigment dispersant, 3.0 g, Triethylene glycol divinyl ether (manufactured by Nippon Carbide) (40 g), 0.5 mm zirconia beads 200 g (200 parts by mass) and 100 ml of polypropylene in a sealed container, dispersion is performed for 6 hours using a paint shaker (RED DEVICE EQUIIPMENT CO. TWIN-ARM ONE-GALLON SHAKER 5400), and pigment dispersion 1 is obtained. Obtained.

[Preparation of ink]
(Preparation of ink 1-1)
3. Pigment Dispersion 1 prepared as described above was mixed with a mixture of Example Compound M-5 and triethylene glycol divinyl ether (manufactured by Nippon Carbide) under the condition that the functional group molar ratio was 35:65. 5% by mass, 3.0% by mass of acylphosphine oxide photopolymerization initiator Lucirin TPO (manufactured by BASF), 2.0% by mass of sensitizer isopropylthioxanthone, and IRGASTAB UV-10 as a polymerization inhibitor (BASF) is mixed so as to be 0.15% by mass, and finally the functional group molar ratio of the exemplified compound M-5 and triethylene glycol divinyl ether (Nippon Carbide) is 35:65. Ink 1-1 was prepared by finishing 100% by mass with the mixed liquid mixture.

(Preparation of ink 1-2 to 1-30)
In the preparation of the ink 1-1, the maleimide compound, triethylene glycol divinyl ether, the compound having a substituent capable of reacting with the nucleophile, the initiator and the sensitizer were changed as shown in Table 1, and the ink 1- 2 to 1-30 were prepared.

The compounds listed in Table 1 are as follows:
TEGDVE: Triethylene glycol divinyl ether (manufactured by Nippon Carbide)
CHVE: cyclohexane dimethanol divinyl ether (manufactured by Nippon Carbide)
NVC: N-vinylcaprolactam (manufactured by BASF)
VCE: Vinyl-m-cresyl ether (synthesized according to known literature)
IB-600: Isoban-600 (manufactured by Kuraray)
EPC: EPICLON EXA-4850-150 (manufactured by DIC)
GB-301: Nack Ace GB-301 (Nihon Unicar)
[Evaluation of ink]
(Evaluation of curability)
Using each ink prepared above, each ink was applied on a plastic corrugated board (thickness 4 mm; made of polypropylene) with a wire bar (No. 3), and an LED with an output of 2 W / cm ² (emission wavelength 385 nm). The film surface was touched by light irradiation, and the curability was evaluated according to the following criteria.

◎: Surface tack (adhesive feeling) disappears when the irradiation integrated light quantity is less than 50 mJ / cm ² ○: Surface tack disappears when the irradiation integrated light quantity is between 50 and 100 mJ / cm ² Δ: Integrated irradiation light quantity is 100 to 200 mJ / cm ^No surface tack between ² ×: Irradiation integrated light quantity is 200 mJ / cm ² or more (durability evaluation)
The coated sample of each ink cured by the above-described evaluation of the curability is irradiated with light, sprayed with water, and heated for 300 hours under the following conditions in a xenon weather meter (XL75; manufactured by Suga Test Instruments) to visually check the surface state of the sample. The durability was evaluated according to the following criteria.

Light irradiation: irradiation with 70.000 lux light for 3 hours and 55 minutes Water spray: water spray for 5 minutes while irradiating light with 70.000 lux Heating: turn off and heat at 60 ° C./95% RH for 4 hours * Repeat above A: No crack or peeling is observed. ○: A fine crack is seen on a part of the image surface. Δ: A crack is seen on 30% or more of the image surface, or a part of the sample is peeled off. 60% or more of the image surface is cracked, or 30% or more is peeled off. The results obtained as described above are shown in Table 2.

  As is clear from the results shown in Table 2, the difference (Δe value) in the e value of the polymerizable compound having the same structure as the unsaturated bond moiety of the two polymerizable compounds defined in the present invention is 2. It can be seen that the ink of the present invention containing a compound having a substituent which is 8 or more and 6.0 or less and can react with a nucleophile is superior in curability and durability to the comparative example.

Example 2
In the inks 1-1 and 1-2 described in Example 1, the pigment type was C.I. I. Pigment red 122 to C.I. I. Pigment Yellow 150 (pigment content 3.5% by mass), C.I. I. Pigment Blue 15: 4 (pigment content 2.5% by mass), carbon black (pigment content 2.5% by mass), and ink 2-1 and 2-2, 3-1 and 3-2, 4-1 and 4-2 were prepared. Ink sets were prepared by combining inks 1-1, 2-1, 3-1, and 4-1, and 1-2, 2-2, 3-2, and 4-2, respectively. Using these ink sets, a piezo head KM512MH manufactured by Konica Minolta IJ, with a droplet amount of 14 pl per dot, 720 dpi × 720 dpi (dpi in the present invention represents the number of dots per 2.54 cm) A solid image (secondary color that combines each single color and two colors) is printed on a plastic cardboard, and a cured image film is formed by irradiating light of 320 mJ / cm ² with a 385 nm LED with an output of 2 W / cm ^2. did. When this was evaluated for durability in Example 1, the ink set using the ink of the present invention showed good durability, but the ink set using the comparative ink was often cracked and peeled off after evaluation. It was seen.

DESCRIPTION OF SYMBOLS 1 Recording device 2 Head carriage 3 Recording head 31 Ink ejection port 4 Irradiation means 5 Platen part 6 Guide member 7 Bellows structure 8 Irradiation light source P Recording medium

Claims (8)

  An active energy ray-curable inkjet ink composition containing at least two kinds of a polymerizable compound having a pigment and an unsaturated double bond, wherein e is an unsaturated double bond portion of the at least two kinds of polymerizable compounds An active energy ray-curable inkjet ink composition comprising a compound having a value difference of 2.8 or more and 6 or less and having a non-polymerizable substituent capable of reacting with a nucleophile. Among the polymerizable compounds having at least two types of unsaturated double bonds, the polymerizable compound having the maximum e value is an unsaturated compound represented by the following general formula (1) or general formula (2). The active energy ray-curable inkjet ink composition according to claim 1, wherein the polymerizable compound having the minimum e value is an unsaturated compound represented by the following general formula (3).

[Wherein, EWG ₁ and EWG ₂ each represent an electron-withdrawing group, and a part of EWG ₁ or EWG ₂ may be bonded to form a cyclic structure. The electron-withdrawing group represents a cyano group, a halogen group, a pyridyl group, a pyrimidyl group, a nitro group, a group represented by the following general formula (a), or a group represented by the following general formula (b). EWG ₁ and EWG ₂ may be bonded to each other to form the following electron-withdrawing linking group to form a cyclic structure. As the linking group, —CO—O—CO—, —CO—N (R _X ) —CO—, —S (O) _n —O—CO—, —S (O) _n —N (R) —CO _{-, - S (O) n} -O-S (O) n -, or _{-S (O) n -N (R} X) -S (O) n - can be exemplified. EWG ₁ and EWG ₂ may form a cyclic structure via a linking group such as a linear alkylene group, a branched alkylene group, a cyclic alkylene group, an alkylene group having a hydroxyl group, an arylene group or an arylalkylene group, and a substituent. You may have. Further, a part of EWG ₁ or EWG ₂ may form a polyfunctional polymerizable compound having two or more unsaturated bonds through a linking group. R _X represents a substituent. ]

[Wherein Q ₁ represents OH, OR ′, NR′R ″ or R ′. R ′ and R ″ each have a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group or a hydroxyl group. An alkyl group, an aryl group or an arylalkyl group is represented. n represents 1 or 2. ]

[Wherein, X represents —O—, —NR _D —, —S—, or —SO—. Y represents a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group, or an arylalkyl group, and may further have a substituent. R _A , R _B , R _C and R _D each independently represent a hydrogen atom, a linear alkyl group, or a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group, or an arylalkyl group; It may have a substituent. Further, a part of R _B or R _C and Y may be bonded to form a cyclic structure. Moreover, you may form the polyfunctional polymerizable compound which one part of Y has a 2 or more unsaturated bond part through a coupling group. ] The unsaturated compound represented by the general formula (1) or the general formula (2) is at least one unsaturated compound selected from the following general formula (A-1) to general formula (A-12). The active energy ray-curable inkjet ink composition according to claim 2.

[Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group or an arylalkyl group. And may further have a substituent, and can be a linking group for forming a polyfunctional polymerizable compound having two or more unsaturated bond moieties. X ₁ represents a halogen atom. ] The unsaturated compound represented by the general formula (3) is at least one unsaturated compound selected from the following general formula (D-1) to general formula (D-9). 4. The active energy ray-curable inkjet ink composition according to 2 or 3.

[Wherein R ₅ to R ₉ each independently represents a hydrogen atom, a linear alkyl group, or a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group or an arylalkyl group, and further a substituent. May be used as a linking group for forming a polyfunctional polymerizable compound having two or more unsaturated bond moieties. Z represents —O—, —N (R ₁₀ ) — or —S—. R ₁₀ represents a hydrogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, an alkyl group having a hydroxyl group, an aryl group, or an arylalkyl group, and may further have a substituent. ]   The unsaturated compound represented by the general formula (1) or the general formula (2) is represented by the general formula (A-1), the general formula (A-2), or the general formula (A-5). The unsaturated compound represented by the general formula (3) is an unsaturated compound represented by the general formula (D-1), the general formula (D-2), or the general formula (D-3). The active energy ray-curable inkjet ink composition according to claim 4, which is a saturated compound.   The active energy ray-curable inkjet ink composition according to claim 1, wherein the nucleophile is a compound containing a hydroxyl group or a carboxyl group. The substituent that can react with the nucleophile is a group represented by the following general formula (4), (5), or (6). Active energy ray-curable inkjet ink composition.

[In General Formula (4), R _D represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. * Represents a binding site.
In General Formula (5), R _E represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. * Represents a binding site.
In general formula (6), * represents a binding site. ]   An ink jet recording method comprising recording an image using the active energy ray-curable ink jet ink composition according to claim 1.

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