JP2007224227A - Ink composition, inkjet recording method and printed matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition curing in high sensitivity and forming high-definition image by irradiation of active radiation, excellent in flexibility of a printed matter and good storage stability and to provide an inkjet recording method using the ink composition and to provide the printed matter excellent in flexibility and obtained by using the ink composition excellent in storage stability and being curable in high sensitivity by irradiation of radiation. <P>SOLUTION: The ink composition comprises (a) a polyfunctional oxetane compound, (b) a polyfunctional oxirane compound, (c) a monofunctional oxetane compound having a highly polar group and/or a monofunctional oxirane compound having a highly polar group, (d) a cation polymerization initiator and (e) a coloring agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink composition suitably used for inkjet recording, an inkjet recording method, and a printed matter using the same. Specifically, an ink composition that can be cured with high sensitivity to radiation irradiation, can form a high-quality image, and has good storage stability, an inkjet recording method suitable for inkjet recording, and The present invention relates to a printed matter using the same.

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

  Ink compositions that can be cured by irradiation with radiation such as ultraviolet rays, in particular ink jet recording inks (radiation curable ink jet recording inks), are required to provide sufficiently high sensitivity and high image quality. By achieving high sensitivity, high curability is imparted to radiation, reducing power consumption, extending life by reducing the load on the radiation generator, preventing the generation of low-molecular substances due to insufficient curing, etc. Profits are generated.

In Patent Document 1, as an active energy ray-curable ink having excellent photopolymerizability and good curability, 1) 10 to 50% by weight of an oxirane group-containing compound, 2) 50 to 90% by weight of an oxetane ring-containing compound, and 3 An active energy ray-curable ink-jet ink comprising 4) a pigment dispersed in a liquid component comprising 0) to 40% by weight of a vinyl ether compound is disclosed. Further, Patent Document 2 discloses an image forming method by an inkjet recording method that has excellent character quality, does not cause color mixing, can record a high-definition image, and does not generate wrinkles or curls of the printed material, and printed material. For the purpose of providing a recording apparatus, an ink containing a photoacid generator and an oxetane compound having a hydrophobic group is disclosed.
Further, Patent Document 3 discloses a dispersant used for pigment dispersion for the purpose of providing an ultraviolet curable ink composition for jet ink recording that has good pigment dispersibility, curability, and solvent resistance without using an organic solvent. And a solvent-free ultraviolet curable jet ink composition comprising a monomer and / or an oligomer that dissolves the dispersant.
However, these ink compositions cannot sufficiently satisfy all the characteristics of sensitivity to active energy rays, flexibility of printed matter, and storage stability of ink.

JP 2002-188025 A JP 2004-18577 A JP 2002-179967 A

The object of the present invention made in consideration of the above-mentioned problems is that it can be cured with high sensitivity by irradiation with actinic radiation, can form a high-quality image, has excellent flexibility of printed matter, and has good storage stability. An ink composition and an ink jet recording method using the ink composition are provided.
Another object of the present invention is to provide a printed matter having excellent flexibility and obtained by using an ink composition which is excellent in storage stability and can be cured with high sensitivity by irradiation with radiation.

The above object has been achieved by the means described in <1>, <8> and <9> below. It is shown below with <2>-<7> which are preferable embodiments.
<1> (a) polyfunctional oxetane compound, (b) polyfunctional oxirane compound, (c) monofunctional oxetane compound having a high polar group and / or monofunctional oxirane compound having a high polar group, (d) initiation of cationic polymerization An ink composition comprising an agent and (e) a colorant;
<2> (c) A monofunctional oxetane compound having a high polar group or a monofunctional oxirane compound having a high polar group is an ester bond, carbonate bond, hydroxyl group, amino group, urethane bond, amide bond, urea bond, substituent The ink composition according to <1>, which has at least one selected from the group consisting of a bisphenoxy bond, a nitrogen-containing cyclic compound group, an oxygen-containing cyclic compound group, and an alkylene glycol structure,
<3> (c) The ink composition according to <1> or <2>, wherein the monofunctional oxetane compound having a highly polar group or the monofunctional oxirane compound having a highly polar group is a compound having 3 or more total oxygen atoms. object,
<4> (c) The monofunctional oxetane compound having a high polarity group or the monofunctional oxirane compound having a high polarity group does not have a hydrogen bonding group, <1> to <3> An ink composition,
<5> (c) A monofunctional oxetane compound having a highly polar group or a monofunctional oxirane compound having a highly polar group has one 3-membered or 4-membered cyclic ether, and is represented by the formula (1) The ink composition according to any one of <1> to <4>,

（式（１）中、Ｒ₁はアルキレン基、シクロアルキレン基、又はアリーレン基を表す。ｎは１以上の整数を表す。）

(In Formula (1), R ₁ represents an alkylene group, a cycloalkylene group, or an arylene group. N represents an integer of 1 or more.)

<6> (c) The content of the monofunctional oxetane compound having a high polar group and the monofunctional oxirane compound having a high polar group is 5% by weight to 70% by weight of the whole ink, and the content of the polyfunctional oxetane compound is 10 wt% to 50 wt% of the entire ink, the content of the polyfunctional oxirane compound is 10 wt% to 50 wt% of the entire ink, and the total content of the polyfunctional oxirane compound and the polyfunctional oxetane compound is the ink The ink composition according to any one of <1> to <5>, which is 20% to 70% by weight of the total,
<7> The ink composition according to any one of <1> to <6>, which is for inkjet recording.
<8> An inkjet recording method comprising: (a) a step of ejecting an ink composition onto a recording medium; and (b) a step of irradiating the ejected ink composition with active radiation to cure the ink composition. An ink jet recording method, wherein the ink composition is the ink composition according to any one of <1> to <7>,
<9> Printed matter recorded by the inkjet recording method according to <8>.

According to the present invention, an ink composition that can be cured with high sensitivity to radiation irradiation, can form a high-quality image, has excellent flexibility in printed matter, and has good storage stability, and the ink. An ink jet recording method using the composition can be provided.
Moreover, the printed matter obtained by using the ink composition which is excellent in the storage stability and can be cured with high sensitivity by irradiation with radiation has high image quality and excellent flexibility in the image area.

The ink composition of the present invention (hereinafter also simply referred to as “ink”) comprises (a) a polyfunctional oxetane compound, (b) a polyfunctional oxirane compound, (c) a monofunctional oxetane compound having a highly polar group, and / or It contains a monofunctional oxirane compound having a highly polar group, (d) a cationic polymerization initiator, and (e) a colorant.
The present invention will be described in detail below.

(1) Components contained in ink composition The ink composition of the present invention is curable by radiation, and includes (a) a polyfunctional oxetane compound, (b) a polyfunctional oxirane compound, and (c) a single group having a highly polar group. A functional oxetane compound and / or a monofunctional oxirane compound having a highly polar group, (d) a cationic polymerization initiator, and (e) a colorant, and if necessary, (f) a co-sensitizer, (g ) Other polymerizable compounds, (h) other polymerization initiators, (i) may contain other components.
The “radiation” referred to in the present invention is not particularly limited as long as it is an actinic radiation that can impart energy capable of generating an initial species in the ink composition by irradiation, and is broadly α-ray, γ-ray, X Among these, ultraviolet rays and electron beams are preferable, and ultraviolet rays and electron beams are particularly preferable from the viewpoints of curing sensitivity and device availability. Therefore, the ink composition of the present invention is preferably an ink composition that can be cured by irradiating ultraviolet rays as radiation.

In the present invention, when a specific portion is referred to as a “group”, the substituent is substituted even if it is substituted with one or more (up to the maximum possible number) substituents, unless otherwise specified. It means that it is not necessary. For example, “alkyl group” means a substituted or unsubstituted alkyl group.
Further, in the present invention, when a specific moiety is referred to as “ring”, or when “ring” is included in “group”, it may be monocyclic or condensed, and may be substituted unless otherwise specified. It may be unsubstituted. For example, the “aryl group” may be a phenyl group or a naphthyl group, or a substituted phenyl group.

(A) Polyfunctional Oxetane Compound The ink composition of the present invention contains (a) a polyfunctional oxetane compound. A polyfunctional oxetane compound is a compound having two or more oxetane rings in the same molecule.
In this invention, a polyfunctional oxetane compound can also be used individually by 1 type, and can also be used in combination of 2 or more type.
The polyfunctional oxetane compound has two or more oxetane rings in the molecule, but preferably has 2 to 6, more preferably 2 to 4. It is preferable for the number of functional groups to be in the above range since good curability and good flexibility of the cured film can be obtained.

  Examples of the compound having two oxetane rings in the molecule include compounds represented by the following formulas (1) and (2).

R ^a1 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, a furyl group, or a thienyl group. When two R ^a1 are present in the molecule, they may be the same or different.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Preferred examples of the fluoroalkyl group include those in which any hydrogen of these alkyl groups is substituted with a fluorine atom.

R ^a3 represents a linear or branched alkylene group, a linear or branched poly (alkyleneoxy) group, a linear or branched unsaturated hydrocarbon group, a carbonyl group or an alkylene group containing a carbonyl group, a carboxyl group Represents an alkylene group containing, an alkylene group containing a carbamoyl group, or a group shown below. Examples of the alkylene group include an ethylene group, a propylene group, and a butylene group. Examples of the poly (alkyleneoxy) group include a poly (ethyleneoxy) group and a poly (propyleneoxy) group. Examples of the unsaturated hydrocarbon group include a propenylene group, a methylpropenylene group, and a butenylene group.

When R ^a3 is the above polyvalent group, R ^a4 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a nitro group, a cyano group, a mercapto group, Represents a lower alkyl carboxyl group, a carboxyl group, or a carbamoyl group.
R ^a5 represents an oxygen atom, a sulfur atom, a methylene group, NH, SO, SO ₂ , C (CF ₃ ) ₂ , or C (CH ₃ ) ₂ .
R ^a6 represents an alkyl group having 1 to 4 carbon atoms or an aryl group, and n is an integer of 0 to 2,000. R ^a7 represents an alkyl group having 1 to 4 carbon atoms, an aryl group, or a monovalent group having the following structure. In the following formula, R ^a8 is an alkyl group having 1 to 4 carbon atoms or an aryl group, and m is an integer of 0 to 100.

  Examples of the compound represented by the formula (1) include 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene (OXT-121: Toagosei Co., Ltd.). Examples of the compound represented by (2) include bis (3-ethyl-3-oxetanylmethyl) ether (OXT-221: Toagosei Co., Ltd.).

  As a compound which has 3-4 oxetane rings in a molecule | numerator, the compound shown by following formula (3) is mentioned, for example.

In the formula (3), R ^a1 has the same ^{meaning as} in the formula (1). In addition, as R ^a9 which is a polyvalent linking group, for example, a branched polyalkylene group having 1 to 12 carbon atoms such as groups represented by the following A to C, a branched poly ( An alkyleneoxy) group or a branched polysiloxy group such as a group represented by E below. j is 3 or 4.

In the above A, R ^a10 represents a methyl group, an ethyl group or a propyl group. Moreover, in said D, p is an integer of 1-10.

  Another embodiment of the oxetane compound that can be suitably used in the present invention includes a compound represented by the following formula (4) having an oxetane ring in the side chain.

In the formula (4), R ^a1 and R ^a8 have the same ^{meaning as} in the above formula. R ^a11 is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group or a trialkylsilyl group, and r is 1 to 4.

  The compound having such an oxetane ring is described in detail in JP-A No. 2003-341217, paragraph numbers 0021 to 0084, and the compound described here can be suitably used in the present invention. In addition, oxetane compounds described in JP-A-2004-91556 can also be used in the present invention. This is described in detail in paragraphs 0022 to 0058.

(B) Polyfunctional oxirane compound The ink composition of the present invention contains a polyfunctional oxirane compound. A polyfunctional oxirane compound is a compound having two or more oxirane rings in the same molecule. In this invention, an oxirane compound can be used individually by 1 type, and can also use 2 or more types of polyfunctional oxirane compounds together.
In the present invention, the polyfunctional oxirane compound has two or more oxirane rings in the molecule, preferably 2 to 6 and more preferably 2 to 4. It is preferable for the oxirane ring in the molecule to be in the above range since sufficient curability and flexibility can be achieved.

  Examples of the polyfunctional oxirane compound include a polyfunctional aromatic oxirane compound, a polyfunctional alicyclic oxirane compound, a polyfunctional aliphatic oxirane compound, and the aromatic oxirane compound includes a polyfunctional oxirane compound having at least one aromatic nucleus. Examples include di- or polyglycidyl ethers produced by the reaction of a monohydric phenol or its alkylene oxide adduct and epichlorohydrin, such as di- or polyglycidyl ether of bisphenol A or its alkylene oxide adduct, hydrogenated bisphenol A or its alkylene. Examples thereof include di- or polyglycidyl ethers of oxide adducts and novolak-type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

The polyfunctional alicyclic oxirane compound is obtained by epoxidizing a compound having at least two cycloalkane rings such as cyclohexene ring or cyclopentene ring with an appropriate oxidizing agent such as hydrogen peroxide or peracid. Preferred are cyclohexene oxide or cyclopentene oxide-containing compounds. Moreover, the cyclohexene dioxide and cyclopentene dioxide containing compound obtained by epoxidizing the compound which has cycloalkadiene rings, such as a cyclohexadiene ring or a cyclopentadiene ring, can also be illustrated.
Examples of the polyfunctional aliphatic oxirane compound include di- or polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, and typical examples thereof include diglycidyl ether of ethylene glycol and diglycidyl of propylene glycol. Polyglycidyl ethers of polyhydric alcohols such as diglycol or diglycidyl ether of alkylene glycol such as ether or 1,6-hexanediol, diglycidyl ether of glycerin or its alkylene oxide adduct, polyethylene glycol or alkylene oxide thereof Polyalkylene glycols typified by diglycidyl ethers of adducts, polypropylene glycol or diglycidyl ethers of adducts thereof with alkylene oxide. Diglycidyl ethers of Lumpur thereof. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

The polyfunctional oxirane compound which can be used for this invention is illustrated in detail.
For example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, epoxy novolac resin, hydrogenated Bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl) -5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4 Epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6′-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene Diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexanecarboxylate), dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1 , 4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol di Glycidyl ether, polypropylene glycol diglycidyl ether, 1,13-tetradecadiene dioxide, limonene dioxide, 1,2,7,8-diepoxyoctane, 1,2,5,6-diepoxycyclooctane, etc. Can be mentioned.

  Among these polyfunctional oxirane compounds, polyfunctional aromatic oxirane compounds and polyfunctional alicyclic oxirane compounds are preferable from the viewpoint of excellent curing speed, and polyfunctional alicyclic oxirane compounds are particularly preferable.

(C) Monofunctional oxetane compound having a high polar group, monofunctional oxirane compound having a high polar group The ink composition of the present invention has (c) a monofunctional oxetane compound having a high polar group and / or a high polar group. Contains a monofunctional oxirane compound (hereinafter also referred to as “specific cyclic ether compound”).
In the present invention, good dispersibility can be obtained by containing a monofunctional oxetane compound having a highly polar group or a monofunctional oxirane compound having a highly polar group.
The oxetane compound having a highly polar group and the monofunctional oxirane compound having a highly polar group can be used singly or in combination of two or more. Only a monofunctional oxetane compound having a highly polar group can be used, or only a monofunctional oxirane compound having a highly polar group can be used, or both can be used in combination.

In the present invention, the highly polar group means an ester bond, a carbonate bond, a hydroxyl group, an amino group, a urethane bond, an amide bond, a urea bond, a bisphenoxy bond, or a nitrogen-containing cyclic compound group that may have a substituent. , A functional group containing a highly polar group such as an oxygen-containing cyclic compound group or an alkylene glycol structure. Examples of the alkylene glycol structure include alkylene glycol chains such as ethylene glycol chain, propylene glycol chain, and tetraethylene glycol chain, and polyalkylene glycol chains such as polyethylene glycol chain, polypropylene glycol chain, and polytetraethylene glycol chain.
In the present invention, it is preferable to have an alkylene glycol structure as a highly polar group, and it is particularly preferable to have a polyalkylene glycol structure. Furthermore, it preferably has an ethylene glycol structure, a polyethylene glycol structure and a polypropylene glycol structure.
The total number of oxygen atoms contained in the monofunctional oxetane compound or monofunctional oxirane compound having a highly polar group is preferably 3 or more. The total number of oxygen atoms is more preferably 3-7. When the total number of oxygen atoms is 3 or more, the ink composition can be kept at a low viscosity, and further good dispersion stability is provided, which is preferable.
In the present invention, the high polar group is preferably an ether bond, a polyalkylene glycol chain, an ester bond or a carbonate bond, more preferably a polyethylene glycol chain or a polypropylene glycol chain.

In the present invention, the specific cyclic ether compound preferably has no hydrogen bonding group. Here, the hydrogen bonding group means a substituent having a hydrogen bond.
The substituent having a hydrogen bond means a substituent having a heteroatom having a high electronegativity and having a hydrogen atom as a substituent and containing a functional group or a linking group capable of hydrogen bonding between molecules. Includes substituents containing a hydroxyl group, a mono-, dihydro-substituted amino group, a thiol group, an amide bond, a urea bond, and the like. It is preferable not to have a hydrogen bonding group as a substituent because the ink composition can be kept at low viscosity and good dispersion stability can be obtained.

  In the present invention, the monofunctional oxetane compound having a highly polar group and the monofunctional oxirane compound having a highly polar group are partial structures containing a cyclic ether (an oxetane ring or an oxirane ring, hereinafter referred to as “cyclic ether structure” as appropriate). And a partial structure represented by the following formula (II) (hereinafter appropriately referred to as “alkylene glycol structure”) in the molecular structure is particularly preferable.

In the partial structure represented by the formula (II), R ¹ represents an alkylene group, a cycloalkylene group, or an arylene group. n represents an integer of 1 or more. When n is 2 or more, the specific cyclic ether compound has a polyalkylene structure.

(Cyclic ether structure)
As the cyclic ether structure, a cyclic ether having 3 or 4 carbon atoms is used. Specific examples of the cyclic ether contained in the cyclic ether structure are the cyclic ethers shown below from the viewpoint of reactivity.

  The partial structure (I) may further have a substituent when it can be introduced, and examples of the substituent include a halogen atom, an alkoxy group, an aryloxy group, a nitro group, and an amino group. .

  One partial structure (I) is included in the specific cyclic ether compound.

In the partial structure represented by the formula (II) (partial structure (II)), R ¹ represents an alkylene group, a cycloalkylene group, or an arylene group.
Examples of the alkylene group represented by R ¹ include alkylene groups having 2 to 12 (preferably 2 to 8, more preferably 2 to 6) carbon atoms. Specific examples include an ethylene group, a propylene group, an isopropylene group, a butylene group, a pentylene group, and a hexylene group.

Examples of the cycloalkylene group represented by R ¹ include cycloalkylene groups having 4 to 12 (preferably 4 to 8, more preferably 5 to 7) carbon atoms. Specific examples include groups in which one hydrogen atom has been removed from a group such as a cycloheptyl group, a cyclohexyl group, a cyclopentyl group, or a bicyclo ring group.
Examples of the arylene group represented by R ¹ include an arylene group having 6 to 12 carbon atoms (preferably 6 to 12, more preferably 6 to 8). Specifically, a phenyl group, a biphenyl group, a naphthyl group, and a benzyl group are preferable, and a group obtained by removing one hydrogen atom from a group such as a phenyl group or a benzyl group can be given.

R ¹ may further have a substituent when it can be introduced. Examples of the substituent include a halogen atom, an alkoxy group, an aryloxy group, a nitro group, and an amino group. However, an alkylene group, a cycloalkylene group, or an arylene group having no substituent is preferable.

  n shows an integer greater than or equal to 1, the integer of 1-8 is preferable, the integer of 1-6 is more preferable, and the integer of 2-4 is especially preferable.

The partial structure (II) is preferably linked to a carbon atom in the cyclic ether (oxetane ring or oxirane ring) contained in the partial structure (I) via a linking group such as an alkylene group.
One partial structure (II) may be contained in the specific cyclic ether compound, or two or more thereof may be contained.

As the specific cyclic ether compound, one partial structure (I) is contained in the specific cyclic ether compound, and further, it is an oxetane structure having 3 carbon atoms. In the partial structure (II), R ¹ has ¹ carbon atom. A combination in which an alkyl group of ˜4 and n is an integer of 2 to 4 is a particularly preferred embodiment.

  Hereinafter, typical specific examples [Exemplary compounds (1) to (57)] of the specific cyclic ether compound according to the present invention will be listed, but the present invention is not limited to these specific examples.

In the present invention, the content of the specific cyclic ether compound is 5% to 70% by weight of the whole ink, the content of the polyfunctional oxetane compound is 10% to 50% by weight of the whole ink, and the polyfunctional oxirane compound The content of the polyfunctional cyclic ether compound (the total amount of the polyfunctional oxetane compound and the polyfunctional oxirane compound) is 20% by weight to 70% by weight of the whole ink. Preferably there is.
More preferably, the content of the specific cyclic ether compound is 5% by weight to 40% by weight of the whole ink, and further preferably 5% by weight to 30% by weight.
It is preferable to set the content of the specific cyclic ether compound within the above range because good curability and good flexibility of the cured film can be obtained.

(D) Cationic polymerization initiator The ink composition of the present invention contains (d) a cationic polymerization initiator. As the cationic polymerization initiator (photoacid generator) that can be used in the present invention, for example, a chemical amplification type photoresist or a compound used for photocationic polymerization is used (Organic Electronics Materials Research Group, “For Imaging”). “Organic materials”, Bunshin Publishing (1993), pages 187-192). Examples of the cationic polymerization initiator suitable for the present invention are listed below.

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

  The (d) cationic polymerization initiator that can be used in the present invention may be used alone or in combination of two or more. In the present invention, (d) the cationic polymerization initiator is contained in an amount of preferably 0.01 to 20 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. Is appropriate.

(E) Colorant The ink composition of the present invention contains (e) a colorant.
The colorant that can be used in the present invention is not particularly limited, but pigments and oil-soluble dyes that are excellent in weather resistance and excellent in color reproducibility are preferable, and are selected from any known colorant such as a soluble dye. Can be used. The colorant that can be suitably used in the ink composition of the present invention or the ink composition for inkjet recording preferably does not function as a polymerization inhibitor in a polymerization reaction that is a curing reaction. This is because the sensitivity of the curing reaction by actinic radiation is not reduced.

(E-1) Pigment The pigment that can be used in the present invention is not particularly limited. For example, organic or inorganic pigments having the following numbers described in the color index can be used.

  That is, as red or magenta pigment, Pigment Red 3, 5, 19, 22, 31, 38, 43, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49: 1, 53 : 1, 57: 1, 57: 2, 58: 4, 63: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 88, 104, 108, 112, 122, 123, 144 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange 13, 16, 20, 36, blue or cyan pigments include Pigment Blue 1, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16 17-1, 22, 27, 28, 29, 36, 60, as green pigment, Pigment Green 7, 26, 36, 50, as yellow pigment, Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193, Pigment Black 7, 28, 26 as the black pigment, and Pigment White 6, 18, 21, etc. as the white pigment can be used according to the purpose.

(E-2) Oil-soluble dye The oil-soluble dye that can be used in the present invention is described below.
The oil-soluble dye that can be used in the present invention means a dye that is substantially insoluble in water. Specifically, the solubility in water at 25 ° C. (the mass of the dye that can be dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. Accordingly, the oil-soluble dye means a so-called water-insoluble pigment or oil-soluble dye, and among these, an oil-soluble dye is preferable.

  In the present invention, the oil-soluble dye may be used alone or in combination of several kinds. In addition, other water-soluble dyes, disperse dyes, pigments, and other colorants may be contained as necessary as long as the effects of the present invention are not impaired.

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

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

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

  Each of the above dyes may exhibit yellow, magenta, and cyan colors only after part of the chromophore is dissociated. In this case, the counter cation is an alkali metal or an inorganic cation such as ammonium. Alternatively, it may be an organic cation such as pyridinium or a quaternary ammonium salt, and may further be a polymer cation having these in a partial structure.

  Although not limited to the following, preferred specific examples include C.I. I. Solvent Black 3, 7, 27, 29 and 34; C.I. I. Solvent Yellow 14, 16, 19, 29, 30, 56, 82, 93 and 162; C.I. I. Solvent Red 1, 3, 8, 18, 24, 27, 43, 49, 51, 72, 73, 109, 122, 132 and 218; I. Solvent Violet 3; C.I. I. Solvent Blue 2,11,25,35,38,67 and 70; I. Solvent Green 3 and 7; I. Solvent orange 2; and the like. Among these, particularly preferred are the Black Black PC-0850, Oil Black HBB, Oil Yellow 129, Oil Yellow 105, Oil Pink 312, Oil Red 5B, Oil Scallet 308, Vali Fast Blue chemistry 2606e Bile 2OSe 2B eO (Manufactured by Co., Ltd.), Aizen Spillon Blue GNH (manufactured by Hodogaya Chemical Co., Ltd.), Neopen Yellow 075, Neopen Magenta SE1378, Neopen Blue 808, Neopen Blue FF4012, and Neo42 Cy FF4012.

  In the present invention, a disperse dye can be used as long as it is soluble in a water-immiscible organic solvent. Preferred examples thereof include C.I. I. Disperse Yellow 5,42,54,64,79,82,83,93,99, 100,119,122,124,126,160,184: 1,186,198,199,201,204,224 and 237 C. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54, 55, 66, 73, 118, 119 and 163; I. Disperse Red 54, 60, 72, 73, 86, 88, 91, 92, 93, 111, 126, 127, 134, 135, 143, 145, 152, 153, 154, 159, 164, 167: 1,177 , 181, 204, 206, 207, 221, 239, 240, 258, 277, 278, 283, 311, 323, 343, 348, 356 and 362; I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 165, 165: 1, 165: 2, 176, 183, 185, 197, 198, 201, 214, 224, 225 , 257, 266, 267, 287, 354, 358, 365 and 368; I. Disperse Green 6: 1 and 9;

  Particularly preferred oil-soluble dyes include azo or azomethine dyes represented by the following formula (1) or (2). The dye represented by the following formula (2) is known as a dye formed from a coupler and a developing agent by oxidation in a photographic material.

In the above formulas (1) and (2), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, halogen atom, aliphatic group, aromatic group, heterocyclic group, cyano group, hydroxy group , Nitro group, amino group, alkylamino group, alkoxy group, aryloxy group, amide group, arylamino group, ureido group, sulfamoylamino group, alkylthio group, arylthio group, alkoxycarbonylamino group, sulfonamido group, carbamoyl Group, sulfamoyl group, sulfonyl group, alkoxycarbonyl group, heterocyclic oxy group, azo group, acyloxy group, carbamoyloxy group, silyloxy group, aryloxycarbonyl group, aryloxycarbonylamino group, imide group, heterocyclic thio group, sulfinyl Group, phosphoryl group, acyl group, carboxyl group or sulfo group Represents a group.

In the formulas (1) and (2), in particular, R ² is a hydrogen atom, a halogen atom, an aliphatic group, an alkoxy group, an aryloxy group, an amide group, a ureido group, or a sulfamoylamino group among the above substituents. It is preferably an alkoxycarbonylamino group or a sulfonamide group.

In the present invention, the aliphatic group means an alkyl group, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an alkynyl group, a substituted alkynyl group, an aralkyl group and a substituted aralkyl group. The aliphatic group may have a branch or may form a ring. The number of carbon atoms in the aliphatic group is preferably 1-20, and more preferably 1-18. The aryl part of the aralkyl group and the substituted aralkyl group is preferably phenyl or naphthyl, particularly preferably phenyl. Examples of the substituent of the alkyl moiety of the substituted alkyl group, the substituted alkenyl group, the substituted alkynyl group, and the substituted aralkyl group include the substituents exemplified in the description of R ^{1 to} R ⁴ . The example of the substituent of the aryl part of a substituted aralkyl group is the same as the example of the substituent of the following substituted aryl group.

In the present invention, the aromatic group means an aryl group and a substituted aryl group. The aryl group is preferably phenyl or naphthyl, particularly preferably phenyl. The aryl part of the substituted aryl group is the same as the above aryl group. Examples of the substituent of the substituted aryl group include the substituents exemplified in the description of R ^{1 to} R ⁴ .

In the formulas (1) and (2), A represents —NR ⁵ R ⁶ or a hydroxy group, and R ⁵ and R ⁶ each independently represents a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group. . A is preferably —NR ⁵ R ⁶ . R ⁵ and R ⁶ may be bonded to each other to form a ring. R ⁵ and R ⁶ are each preferably a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, each having a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or 1 carbon atom. Most preferred is a substituted alkyl group of ˜18.

In the formula (2), B ¹ represents = C (R ³ )-or = N-, and B ² represents -C (R ⁴ ) = or -N =. The case where B ¹ and B ² are not simultaneously -N = is preferred, and the case where B ¹ is = C (R ³ )-and B ² is -C (R ⁴ ) = is more preferred. Any of R ¹ and R ⁵ , R ³ and R ^6, and R ¹ and R ² may be bonded to each other to form an aromatic ring or a heterocyclic ring.

In the formula (1), Y represents an unsaturated heterocyclic group. Y is preferably a 5-membered or 6-membered unsaturated heterocyclic ring. The heterocyclic ring may be condensed with an aliphatic ring, an aromatic ring or another heterocyclic ring. N, O, and S can be mentioned as an example of the hetero atom of a heterocyclic ring.
Examples of the unsaturated heterocyclic ring include pyrazole ring, imidazole ring, thiazole ring, isothiazole ring, thiadiazole ring, thiophene ring, benzothiazole ring, benzoxazole ring, benzoisothiazole ring, pyrimidine ring, pyridine ring, and quinoline. A ring or the like is preferable. In addition, the unsaturated heterocyclic group may have the substituents exemplified in R ^{1 to} R ⁴ .

In the formula (2), X represents a color photographic coupler residue. The following are preferred as the residues of the color photographic coupler.
Yellow coupler: U.S. Pat. Nos. 3,933,501, 4,022,620, 4,326,024, 4,401,752, 4,248,961, and JP-B-58-10939 British Patents 1,425,020, 1,476,760, U.S. Patents 3,973,968, 4,314,023, 4,511,649, European Patent 249,473A, Couplers represented by formulas (I) and (II) of No. 502,424A, couplers represented by formulas (1) and (2) of No. 513,496A (particularly Y-28 on page 18), No. 568,037A, the coupler represented by formula (I) of claim 1, US Pat. No. 5,066,576, column 1, line 45 to 55, the coupler represented by formula (I), JP-A-4-274425 Formula (I) in paragraph 0008 of the Gazette Couplers described in claim 1 on page 40 of European Patent 498,381A1 (particularly D-35 on page 18), couplers represented by formula (Y) on page 4 of 447,969A1 ( In particular, Y-1 (page 17), Y-54 (page 41)), couplers represented by formulas (II) to (IV) in columns 7 to 58 of U.S. Pat. No. 4,476,219 (column 7). In particular, II-17, 19 (column 17), II-24 (column 19)).

  Magenta couplers: US Pat. Nos. 4,310,619, 4,351,897, European Patent 73,636, US Pat. Nos. 3,061,432, 3,725,067, Research Disclosure No. 24220 (June 1984), ibid. 24230 (June 1984), JP-A-60-33552, JP-A-60-43659, JP-A-61-72238, JP-A-60-35730, JP-A-55-118034, JP-A-60-185951, U.S. Pat. No. 500,630, No. 4,540,654, No. 4,556,630, International Publication No. WO88 / 04795, JP-A-3-39737 (L-57 (page 11, lower right), L-68 (12 (Lower right of page), L-77 (lower right of page 13)), [A-4] -63 (page 134), [A-4] -73, -75 (page 139) of European Patent 456,257, 486, 965, M-4, -6 (page 26), M-7 (page 27), 571, 959A, M-45 (page 19), and JP-A-5-204106, M-1 (Page 6), paragraph 0237 M- 2, US Pat. No. 3,061,432 and No. 3,725,067.

  Cyan coupler: U.S. Pat. Nos. 4,052,212, 4,146,396, 4,228,233, 4,296,200, European Patent 73,636, Japanese Patent Laid-Open No. 4-204843 CX-1,3,4,5,11,12,14,15 (pages 14 to 16); JP-A-4-43345, C-7,10 (page 35), 34,35 (page 37), ( I-1), (I-17) (pages 42 to 43); couplers represented by formula (Ia) or (Ib) of claim 1 of JP-A-6-67385.

  Other couplers described in JP-A-62-215272 (page 91), JP-A-2-33144 (pages 3, 30), EP 355,660A (pages 4, 5, 45, 47) Is also useful.

  Of the oil-soluble dyes represented by the formula (1), a dye represented by the following formula (3) is particularly preferably used as the magenta dye.

In the formula (3), Z ¹ represents an electron-withdrawing group having a Hammett's substituent constant σp value of 0.20 or more. Z ¹ is preferably an electron-withdrawing group having a σp value of 0.30 or more and 1.0 or less. Preferred examples of the substituent include an electron-withdrawing substituent described later. Among them, an acyl group having 2 to 12 carbon atoms, an alkyloxycarbonyl group having 2 to 12 carbon atoms, a nitro group, a cyano group, An alkylsulfonyl group having 1 to 12 carbon atoms, an arylsulfonyl group having 6 to 18 carbon atoms, a carbamoyl group having 1 to 12 carbon atoms, and a halogenated alkyl group having 1 to 12 carbon atoms are preferable. Particularly preferred are a cyano group, an alkylsulfonyl group having 1 to 12 carbon atoms, and an arylsulfonyl group having 6 to 18 carbon atoms, and most preferred is a cyano group.

In the formula (3), Z ² represents a hydrogen atom, an aliphatic group or an aromatic group.
In said Formula (3), R < ¹ > -R < ⁶ > is synonymous with each of the said Formula (1).

In the formula (3), Q represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group. Among these, Q is preferably a group composed of a nonmetallic atom group necessary for forming a 5- to 8-membered ring. Among these, an aromatic group or a heterocyclic group is particularly preferable. The 5- to 8-membered ring may be substituted, may be a saturated ring, or may have an unsaturated bond. Preferred nonmetallic atoms include nitrogen atoms, oxygen atoms, sulfur atoms or carbon atoms. Specific examples of such a ring structure include, for example, a benzene ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, cyclohexene ring, pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, imidazole ring. , A benzimidazole ring, an oxazole ring, a benzoxazole ring, an oxane ring, a sulfolane ring, a thiane ring, and the like. When these rings further have a substituent, the substituent is the substituent of the formula (1). group exemplified in R ¹ to R ⁴ can be mentioned.

  In addition, about the preferable structure of the compound represented by the said Formula (3), it describes in Unexamined-Japanese-Patent No. 2001-335714.

  Of the dyes represented by the formula (2), a dye represented by the following formula (4) is particularly preferably used as the magenta dye.

  In the above formula (4), G is a hydrogen atom, aliphatic group, aromatic group, heterocyclic group, cyano group, alkoxy group, aryloxy group, alkylthio group, arylthio group, ester group, amino group, carbamoyl group, sulfonyl group Represents a group, a sulfamoyl group, a ureido group, a urethane group, an acyl group, an amide group or a sulfonamide group.

In said formula (4), R < ¹ >, R < ² >, A, B < ¹ > and B < ² > are synonymous with each of said formula (2), and those preferable ranges are also the same.

  In the formula (4), L is an aliphatic group, aromatic group, heterocyclic group, cyano group, alkoxy group, aryloxy group, alkylthio group, arylthio group, ester group, amino group, carbamoyl group, sulfonyl group, sulfamoyl. Represents a group of atoms that form a 5- or 6-membered nitrogen-containing heterocycle optionally substituted with at least one of a group, a ureido group, a urethane group, an acyl group, an amide group, and a sulfonamide group, Furthermore, a condensed ring may be formed with another ring.

In the compound represented by the formula (4), A is preferably —NR ⁵ R ⁶ , L preferably forms a 5-membered nitrogen-containing heterocyclic ring, and examples of the 5-membered nitrogen-containing heterocyclic ring include imidazole. Rings, triazole rings and terazole rings are included.

Examples of magenta dye compounds (M-0 to 6, a-21 to 25) among the dyes represented by the formula (1) and the formula (2) are shown below. It is for explaining in detail, and the present invention is not limited by these.
In the present invention, M-0, M-4, M-6, and a-21 can be used, and M-4, M-6, and a-21 can be particularly preferably used.

  Other examples of the colorant compound that can be used in the present invention are described in, for example, JP-A Nos. 2001-240763, 2001-181549, and JP-A-2001-335714. It is not limited to these.

  The compound represented by the formula (3) can be synthesized, for example, with reference to the methods described in JP-A Nos. 2001-335714 and 55-161856. The compound represented by the formula (4) can be obtained by referring to, for example, methods described in JP-A-4-1267772 and JP-B-7-94180 and JP-A-2001-240763. Can be synthesized.

  Of the dyes represented by the formula (2), a pyrrolotriazole azomethine dye represented by the following formula (5) can be particularly preferably used as the cyan dye.

In the formula (5), A, R ¹ , R ² , B ¹ and B ² have the same meanings as those in the formula (2), and preferred ranges thereof are also the same.

In the formula (5), Z ³ and Z ⁴ are each independently synonymous with G in the formula (4). Z ³ and Z ⁴ may be bonded to each other to form a ring structure. It is more preferable that Z ³ is an electron-withdrawing group having a Hammett substituent constant σp value of 0.30 or more because the absorption is sharp. Z ³ is more preferably an electron-withdrawing group having a Hammett substituent constant σp value of 0.45 or more, and most preferably an electron-withdrawing group having a Hammett substituent constant σp value of 0.60 or more. And those having a sum of Hammett substituent constants σp values of Z ³ and Z ⁴ of 0.70 or more exhibit an excellent hue as cyan, and are more preferable.

In the formula (5), M is an atomic group forming a 1,2,4-triazole ring condensed with the 5-membered ring in the formula (5), and two atoms in the condensed part with the 5-membered ring One of B ³ and B ⁴ is a nitrogen atom and the other is a carbon atom.

  The compound represented by the formula (5) is preferably used as a cyan dye, but can also be used as a magenta dye by changing a substituent.

  Here, Hammett's substituent constant σp value used in this specification will be described. Hammett's rule is an empirical rule proposed by L. P. Hammett in 1935 to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives, which is widely accepted today. Substituent constants determined by Hammett's rule include σp value and σm value, and these values can be found in many general books. For example, JA Dean edition, “Lange's Handbook of Chemistry” 12th edition, 1979 (Mc Graw-Hill), “Chemical domain” extra edition, 122, 96-103, 1979 (Nankodo). In the present invention, each substituent is limited or explained by Hammett's substituent constant σp, but this is limited to only a substituent having a known value that can be found in the above-mentioned book. Needless to say, it also includes substituents that would be included in the range when measured based on Hammett's rule even if the value is unknown. The formulas (1) to (5) include those that are not benzene derivatives, but the σp value is used as a scale indicating the electronic effect of the substituent regardless of the substitution position. In the present invention, the σp value is used in this sense.

  Examples of the electron-withdrawing group having a Hammett substituent constant σp value of 0.60 or more include a cyano group, a nitro group, and an alkylsulfonyl group (for example, a methanesulfonyl group and an arylsulfonyl group (for example, a benzenesulfonyl group)). As the electron withdrawing group having a Hammett σp value of 0.45 or more, in addition to the above, an acyl group (for example, acetyl group), an alkoxycarbonyl group (for example, dodecyloxycarbonyl group), an aryloxycarbonyl group (for example, m-chlorophenoxy) Carbonyl), alkylsulfinyl group (for example, n-propylsulfinyl), arylsulfinyl group (for example, phenylsulfinyl), sulfamoyl group (for example, N-ethylsulfamoyl, N, N-dimethylsulfamoyl), halogenated alkyl group (For example, a trif Fluoromethyl).

  As the electron-withdrawing group having a Hammett substituent constant σp value of 0.30 or more, in addition to the above, an acyloxy group (for example, acetoxy), a carbamoyl group (for example, N-ethylcarbamoyl, N, N-dibutylcarbamoyl), halogen Alkoxy group (for example, trifluoromethyloxy), halogenated aryloxy group (for example, pentafluorophenyloxy), sulfonyloxy group (for example, methylsulfonyloxy), halogenated alkylthio group (for example, difluoromethylthio), two An aryl group (for example, 2,4-dinitrophenyl, pentachlorophenyl) substituted with an electron-withdrawing group having a σp value of 0.15 or more, and a heterocyclic ring (for example, 2-benzoxazolyl, 2-benzothiazolyl) 1-phenyl-2-benzimidazolyl) Can. Specific examples of the electron-withdrawing group having a σp value of 0.20 or more include a halogen atom in addition to the above.

  Moreover, in this invention, the oil-soluble dye represented by a following formula (AI) can be used preferably.

In formula (AI): X ₁ , X ₂ , X ₃ and X ₄ are each independently —SO—Z, —SO ₂ —Z, —SO ₂ NR ₁ R ₂ , —CONR ₁ R ₂ , It represents a group selected from -CO ₂ R ₁ and a sulfo group. Here, Z is a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted group. Represents a substituted heterocyclic group. R ₁ and R ₂ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, substituted or unsubstituted It represents a substituted aryl group or a substituted or unsubstituted heterocyclic group. However, R ₁ and R ₂ are not both hydrogen atoms. M represents a hydrogen atom, a metal element, a metal oxide, a metal hydroxide, or a metal halide. Y ₁ , Y ₂ , Y ₃ and Y ₄ each independently represent a hydrogen atom or a monovalent substituent. _{a 1 ~a 4, b 1 ~b} 4 represents the number of _{X 1 ~X 4, Y 1 ~Y} 4, each independently, an integer of 0-4. However, the sum of a _{1 to} a ₄ is 2 or more.

  Of the oil-soluble dyes represented by the formula (AI), an oil-soluble dye represented by the following formula (A-II) can be particularly preferably used.

Formula (A-II) _{in: X 11 ~X 14, Y 11} ~Y 18 , and M are the same as _{X 1 ~X 4, Y 1 ~Y} 4, M in Formula (A-I) synonymous . a ₁₁ ~a ₁₄ each independently represent a integer of 1 or 2.

  Illustrative compound (AII-17) is shown as a specific example of formula (A-II), but this is for the purpose of illustrating the present invention in detail, and the present invention is not limited thereby. .

  In the present invention, it is preferable to use an oil-soluble dye having an oxidation potential nobler than 1.0 V (SCE). The oxidation potential is more preferable as it is noble, the oxidation potential is more noble than 1.1 V (SCE), more preferably 1.2 V (SCE).

  A person skilled in the art can easily measure the value of the oxidation potential (Eox). Regarding this method, for example, “New Instrumental Methods in Electrochemistry” by P. Delahay (1954, published by Interscience Publishers), “Electrochemical Methods” by AJ Bard et al. (1980, published by John Wiley & Sons), Akira Fujishima et al. It is described in the book "Electrochemical measurement method" (1984, published by Gihodo Publishing Co., Ltd.).

Specifically, the oxidation potential is 1 × 10 ⁻⁴ to 1 × 10 ⁻⁶ mol / in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate. Approximate the oxidization wave in a straight line by dissolving 1 liter and sweeping to the oxidation side (noble side) using carbon (GC) as the working electrode and rotating platinum electrode as the counter electrode by cyclic voltammetry and DC polarography equipment Then, the intermediate potential of the line segment formed by the intersection of this straight line and the residual current / potential line and the intersection of the straight line and the saturation current line (or the intersection of the straight line parallel to the vertical axis passing through the peak potential value) Values are measured as values for SCE (saturated calomel electrode). Although this value may be deviated by several tens of mil volts due to the influence of the liquid potential difference or the liquid resistance of the sample solution, the reproducibility of the potential can be ensured by inserting a standard sample (for example, hydroquinone). The supporting electrolyte and solvent to be used can be selected appropriately depending on the oxidation potential and solubility of the test sample. The supporting electrolytes and solvents that can be used are described in Akira Fujishima et al., “Electrochemical measurement method” (1984, published by Gihodo Publishing Co., Ltd.), pages 101 to 118.
In the concentration range of the measurement solvent and the phthalocyanine compound sample, the oxidation potential in a non-associated state is measured.

The value of Eox represents the ease of transfer of electrons from the sample to the electrode, and the greater the value (the higher the oxidation potential), the less transfer of electrons from the sample to the electrode, in other words, less oxidation.
When a dye having a low oxidation potential is used, polymerization inhibition by the dye is large and curability is lowered. When a dye having a noble oxidation potential is used, there is almost no polymerization inhibition.

The colorant that can be used in the present invention is preferably added to the ink composition of the present invention or the ink composition for inkjet recording and then appropriately dispersed in the ink. For dispersing the colorant, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, or a paint shaker can be used.
It is also possible to add a dispersant when dispersing the colorant. The type of the dispersant is not particularly limited, but a polymer dispersant is preferably used, and examples of the polymer dispersant include Solsperse series manufactured by Zeneca. Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. In the present invention, these dispersant and dispersion aid are preferably added in an amount of 1 to 50 parts by weight with respect to 100 parts by weight of the colorant.
The colorant may be added directly to the ink composition of the present invention, but may be added in advance to a dispersion medium such as a solvent or a polymerizable compound used in the present invention in order to improve dispersibility. In the present invention, in order to avoid the problem of deterioration of solvent resistance when the solvent remains in the cured image and the problem of VOC (Volatile Organic Compound) of the remaining solvent, the colorant is added to the polymerizable compound. It is preferable to add. Further, as a polymerizable compound to be used, it is preferable in view of dispersion suitability to select a monomer having the lowest viscosity.

  In the present invention, the average particle diameter of the colorant particles is preferably 0.005 to 0.5 μm, more preferably 0.01 to 0.45 μm, and still more preferably 0.015 to 0.3 μm. The maximum particle size of the colorant is preferably 0.3 to 10 μm, more preferably 0.3 to 3 μm. It is preferable to set the colorant, the dispersant, the dispersion medium, the dispersion conditions, and the filtration conditions so that the maximum particle diameter is obtained. This particle size control is preferable because clogging of the head nozzle can be suppressed and ink storage stability, ink transparency, and curing sensitivity can be maintained.

  The colorant is preferably added in the ink composition in an amount of 1 to 20% by weight, more preferably 2 to 15% by weight based on the total weight of the ink composition.

(F) Co-sensitizer The ink composition of the present invention preferably contains (f) a co-sensitizer. In the present invention, the co-sensitizer has functions such as further improving the sensitivity of the sensitizing dye to actinic radiation or suppressing polymerization inhibition of the polymerizable compound by oxygen.
Examples of such co-sensitizers include amines such as MR Sander et al., “Journal of Polymer Society”, Vol. 10, page 3173 (1972), Japanese Examined Patent Publication No. 44-20189, Japanese Patent Laid-Open No. 51-82102. Publication, JP 52-134692, JP 59-138205, JP 60-84305, JP 62-18537, JP 64-33104, Research Disclosure 33825 Specifically, triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like can be mentioned.

  Other examples of co-sensitizers include thiols and sulfides, for example, thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142773, and JP-A-56. And the like. Specific examples include 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzoimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercaptonaphthalene. Etc.

  Other examples include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in Japanese Patent Publication No. 48-42965 (eg, tributyltin acetate), and hydrogen described in Japanese Patent Publication No. 55-34414. Donors, sulfur compounds described in JP-A-6-308727 (eg, trithiane), phosphorus compounds described in JP-A-6-250387 (diethylphosphite, etc.), Si-- described in Japanese Patent Application No. 6-191605 H, Ge-H compound, etc. are mentioned.

  The co-sensitizer is preferably added in the ink composition in an amount of 1 to 20% by weight, more preferably 1 to 5% by weight based on the weight of the entire ink composition (in terms of solid content).

(G) Other polymerizable compound The ink composition of the present invention comprises (a) a polyfunctional oxetane compound, (b) a polyfunctional oxirane compound, (c) a specific cyclic ether compound, and (g) another polymerizable compound. You can also Examples of the polymerizable compound that can be used in combination with the present invention include cationic polymerizable compounds and radical polymerizable compounds that do not fall under (a) to (c). Examples of the radical polymerizable compound are described in JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, JP-A-10-863, JP-A-7-231444, and the like. A photocurable material using a photopolymerizable composition that has been used is known.

  The radically polymerizable compound that can be used in the present invention is a compound having one or more carbon-carbon double bonds (ethylenically unsaturated bonds) capable of radical polymerization, and ethylenically unsaturated capable of radical polymerization in the molecule. Any compound having one bond may be used, including compounds having chemical forms such as monomers, oligomers and polymers. 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.

Examples of the polymerizable compound having an ethylenically unsaturated bond capable of radical polymerization include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, and salts thereof, Examples thereof include radically polymerizable compounds such as anhydrides having a saturated group, acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes.
Specifically, acrylic acid derivatives such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, diacetone acrylamide, epoxy acrylate, methyl methacrylate, Examples include methacryl derivatives such as n-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, and other derivatives of allyl compounds such as allyl glycidyl ether. Is Yamashita Shinzo, “Crosslinking agent handbook” (1981 Taiseisha); Kato Vision, “UV / EB Curing Handbook (Raw Materials)” (1985, Polymer Publications); Radtech Study Group, “Application and Market of UV / EB Curing Technology”, p. 79, (1989, CMC) ); Commercially available products described in Eichiro Takiyama, “Polyester Resin Handbook”, (1988, Nikkan Kogyo Shimbun), or radically polymerizable or cross-linkable monomers, oligomers and polymers known in the industry can be used.
When a radically polymerizable compound and a cationically polymerizable compound are used in combination, a high sensitivity and a low volume shrinkage that is a characteristic of radical polymerization, and a printed material that has both high sensitivity and adhesion, or Since a lithographic printing plate is obtained, it is preferable.

  Moreover, the vinyl ether compound which is a cationically polymerizable compound can also be used together. Examples of the vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, Di- or trivinyl ether compounds such as methylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether, n-propyl Pills vinyl ether, isopropyl vinyl ether, isopropenyl ether -O- propylene carbonate, dodecyl vinyl ether, and a monovinyl ether compounds such as diethylene glycol monovinyl ether.

Below, monofunctional vinyl ether and polyfunctional vinyl ether are illustrated in detail.
Examples of the monofunctional vinyl ether include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, cyclohexyl methyl vinyl ether, 4-methyl Cyclohexylmethyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether , Tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloroethoxy Examples include ethyl vinyl ether, phenyl ethyl vinyl ether, phenoxy polyethylene glycol vinyl ether, and the like.

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

(H) Other Polymerization Initiator The ink composition of the present invention can be used in combination with (d) a cationic polymerization initiator and (h) another polymerization initiator. Examples of the polymerization initiator used in combination include known radical polymerization initiators. The other polymerization initiators may be used alone or in combination of two or more.
The radical polymerization initiator that can be used in the ink composition of the present invention is a compound that absorbs external energy to generate a polymerization initiating species. External energy used for initiating polymerization is roughly divided into heat and actinic radiation, and a thermal polymerization initiator and a photopolymerization initiator are used, respectively. Examples of the active radiation include γ rays, β rays, electron beams, ultraviolet rays, visible rays, and infrared rays. The polymerization initiator that can be used in the present invention is preferably a radiation-sensitive radical polymerization initiator that is sensitive to actinic radiation, so-called photo radical polymerization initiator.

  Preferred radical polymerization initiators that can be used in combination with the present invention include (a) aromatic ketones, (b) organic peroxides, (c) thio compounds, (d) hexaarylbiimidazole compounds, (e) ketoxime esters. Compounds, (f) borate compounds, (g) azinium compounds, (h) metallocene compounds, (i) active ester compounds, (j) compounds having a carbon halogen bond, and (k) alkylamine compounds. These radical polymerization initiators may use the above compounds (a) to (k) alone or in combination.

(I) Other components Other components can be added to the ink composition of the present invention as necessary. Examples of other components include basic compounds, radical polymerization inhibitors, solvents, and the like.
The basic compound is preferably added from the viewpoint of improving the storage stability of the ink composition. As the basic compound that can be used in the present invention, known basic compounds can be used. For example, basic inorganic compounds such as inorganic salts and basic organic compounds such as amines can be preferably used. .
The radical polymerization inhibitor is preferably added from the viewpoint of improving the storage stability. Further, when the ink composition of the present invention is used as an ink composition for ink jet recording, it is preferably discharged at a temperature in the range of 40 to 80 ° C. with a reduced viscosity, and also for preventing head clogging due to thermal polymerization. It is preferable to add a polymerization inhibitor. The polymerization inhibitor is preferably added in an amount of 200 to 20,000 ppm based on the total amount of the ink composition of the present invention. Examples of the polymerization inhibitor include hydroquinone, benzoquinone, p-methoxyphenol, TEMPO, TEMPOL, and cuperon Al.

In view of the fact that the ink composition of the present invention and the ink composition for ink jet recording are radiation curable ink compositions, it is preferable that no solvent is contained so that the ink composition can react quickly and be cured immediately after landing of the ink composition. However, a predetermined solvent can be included as long as the curing rate of the ink composition is not affected. In the present invention, an organic solvent or water can be used as the solvent. In particular, the organic solvent can be added in order to improve the adhesion to the recording medium (support such as paper). The addition of an organic solvent is effective because the problem of volatile organic compounds (VOC) can be avoided. The amount of the organic solvent is, for example, in the range of 0.1 to 5% by weight, preferably 0.1 to 3% by weight, based on the total weight of the ink composition of the present invention.
As a means for preventing a decrease in sensitivity due to the light-shielding effect of the colorant that can be used in the ink composition, in addition to a combination of a cationic polymerizable compound and a cationic polymerization initiator, and a combination of a radical polymerizable compound and a radical polymerization initiator Also, a radical-cation hybrid type curable ink using these polymerizable compounds and a polymerization initiator in combination may be used.

  In addition to this, a known compound can be added to the ink composition of the present invention as necessary. For example, surfactants, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins, waxes and the like are appropriately selected and added. be able to. In order to improve the adhesion to a recording medium such as polyolefin or PET, it is also preferable to contain a tackifier that does not inhibit the polymerization. Specifically, a high molecular weight adhesive polymer described in JP-A-2001-49200, pages 5 to 6 (for example, (meth) acrylic acid and an alcohol having an alkyl group having 1 to 20 carbon atoms). Ester, (meth) acrylic acid and a C3-14 alicyclic alcohol ester, (meth) acrylic acid and a C6-14 aromatic alcohol ester copolymer), and polymerizability Examples thereof include a low molecular weight tackifying resin having an unsaturated bond.

The ink composition of the present invention preferably contains a sensitizer for the purpose of improving the acid generation efficiency of the onium type polymerization initiator and increasing the photosensitive wavelength. As the sensitizer, an onium type polymerization initiator that is sensitized by an electron transfer mechanism or an energy transfer mechanism is preferable. A sensitizing dye is preferable as the sensitizer.
Examples of the sensitizing dye used in the present invention include those belonging to the compounds listed below and having an absorption wavelength in the wavelength region of 300 nm to 450 nm.
Examples of preferred sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region.
For example, polynuclear aromatics (for example, phenanthrene, anthracene, pyrene, perylene, triphenylene, 9,10-dialkoxyanthracene), xanthenes (for example, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), thioxanthones (Isopropylthioxanthone, diethylthioxanthone, chlorothioxanthone), cyanines (eg thiacarbocyanine, oxacarbocyanine), merocyanines (eg merocyanine, carbomerocyanine), phthalocyanines, thiazines (eg thionine, methylene blue, toluidine blue) , Acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, anthraquinone), squariums (eg Squalium), acridine orange, coumarins (eg 7-diethylamino-4-methylcoumarin), ketocoumarins, phenothiazines, phenazines, styrylbenzenes, azo compounds, diphenylmethane, triphenylmethane, distyrylbenzenes Carbazoles, porphyrins, spiro compounds, quinacridone, indigo, styryl, pyrylium compounds, pyromethene compounds, pyrazolotriazole compounds, benzothiazole compounds, barbituric acid derivatives, thiobarbituric acid derivatives, and the like, and further, European Patent No. 568. , 993, U.S. Pat. Nos. 4,508,811, 5,227,227, JP-A-2001-125255, JP-A-11-271969, etc. But It is below.

Among them, the sensitizer in the present invention is used in combination with polynuclear aromatics (for example, phenanthrene, anthracene, pyrene, perylene, triphenylene, 9,10-dialkoxyanthracene), thioxanthones, distyrylbenzenes, and styrylbenzenes. Is preferable from the viewpoint of starting efficiency, and most preferably combined with distyrylbenzenes, styrylbenzene, and diphenylbutadienes.
Specifically, the following compounds can be exemplified.

In the ink composition of the present invention, when a sensitizing dye is used as a sensitizer, the content thereof is 0.01 to 20% by weight with respect to the total weight of the ink composition from the viewpoint of colorability of the ink. Preferably, 0.1 to 15 weight% is more preferable, More preferably, it is the range of 0.5 to 10 weight%.
A sensitizer may be used individually by 1 type and may use 2 or more types together.
In addition, the content ratio of the sensitizer and the onium type polymerization initiator in the ink composition is, in terms of weight ratio, from the viewpoint of improving the decomposition rate of the onium type polymerization initiator and transmitting light (onium type). (Polymerization initiator) / (sensitizer) = 100 to 0.5 is preferable, 50 to 1 is more preferable, and 10 to 1.5 is still more preferable.

(2) Properties of ink composition When the obtained ink composition is used for inkjet recording, the temperature at the time of ejection (for example, 40 to 80 ° C, preferably 25 to 30 ° C) in consideration of ejectability. The viscosity of the ink composition is preferably 7 to 30 mPa · s, more preferably 7 to 20 mPa · s. For example, the viscosity of the ink composition of the present invention at room temperature (25 to 30 ° C.) is preferably 7 to 500 mPa · s, more preferably 7 to 200 mPa · s. It is preferable that the composition ratio of the ink composition of the present invention is appropriately adjusted so that the viscosity is in the above range. By setting the viscosity at room temperature high, even when a porous recording medium is used, ink penetration into the recording medium can be avoided, and uncured monomers and odors can be reduced. Further, it is preferable because ink bleeding at the time of ink droplet landing can be suppressed, and as a result, the image quality is improved.

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

(3) Inkjet recording method and apparatus The ink composition of the present invention is preferably used for inkjet recording.
An ink jet recording method that can be suitably employed in the present invention will be described below.

(3-1) Inkjet recording method The present invention ejects the ink composition onto a recording medium (support, recording material, etc.) and irradiates the ink composition ejected onto the recording medium with active radiation. Thus, a method for forming an image by curing ink is provided. That is, the present invention
(A) a step of discharging the ink composition onto a recording medium; and (b) a step of irradiating the discharged ink composition with active radiation to cure the ink composition;
An inkjet recording method comprising:
The present invention relates to an ink jet recording method in which the ink composition is the ink composition of the present invention.
The cured ink composition forms an image on the recording medium.
The peak wavelength of the active radiation is preferably 200 to 600 nm, more preferably 300 to 450 nm, and more preferably 350 to 420 nm. The output of active radiation is preferably 2,000 mJ / cm ² or less, more preferably from 10 to 2,000 mJ / cm ^2, more preferably be 20 to 1,000 mJ / cm ² Particularly preferably, it is 50 to 800 mJ / cm ² .

(3-1-2) Step of discharging the ink composition onto the recording medium When the ink composition of the present invention or the ink composition for inkjet recording is discharged onto the surface of the recording medium, the ink composition or the inkjet recording The ink composition is preferably heated to 40 to 80 ° C., more preferably 25 to 30 ° C., and the viscosity of the ink composition is preferably lowered to 7 to 30 mPa · s, more preferably 7 to 20 mPa · s. It is preferable to discharge. In particular, it is preferable to use an ink composition having an ink viscosity at 25 ° C. of 7 to 500 mPa · s, more preferably 7 to 200 mPa · s because a great effect can be obtained. By using this method, high ejection stability can be realized. A radiation curable ink composition such as the ink composition of the present invention generally has a higher viscosity than a water-based ink that is usually used in an ink composition or an ink for inkjet recording. Viscosity fluctuation of the ink has a great influence on the change of the droplet size and the change of the droplet discharge speed, and consequently causes the image quality deterioration. Therefore, it is necessary to keep the temperature of the ink at the time of ejection as constant as possible. Therefore, in the present invention, it is appropriate that the temperature control range is set to ± 5 ° C. of the set temperature, preferably ± 2 ° C. of the set temperature, more preferably set temperature ± 1 ° C.

(3-1-3) A step of irradiating the ejected ink composition with actinic radiation to cure the ink composition The ink composition ejected onto the surface of the recording medium irradiates with actinic radiation. It hardens by. This is because the cationic polymerization initiator in the polymerization initiation system contained in the ink composition of the present invention absorbs radiation to generate a photoacid, and the polymerizable compound is cationically polymerized and cured.
Here, α rays, γ rays, electron beams, X rays, ultraviolet rays, visible light, infrared rays, or the like can be used as the active radiation used. The peak wavelength of the actinic radiation is, for example, from 200 to 600 nm, preferably from 300 to 450 nm, more preferably from 350 to 450 nm, although it depends on the absorption characteristics of the sensitizing dye. In the present invention, the polymerization initiation system has sufficient sensitivity even with a low-power active radiation. Therefore, the output of active radiation is, for example, 2,000 mJ / cm ² or less, preferably 10 to 2,000 mJ / cm ² , more preferably 20 to 1,000 mJ / cm ² , and still more preferably 50 to 800 mJ. An irradiation energy of / cm ² is appropriate. The active radiation, the illumination intensity on the exposed surface is, for example, 10 to 2,000 mW / cm ^2, preferably, it is suitable to be irradiated at 20 to 1,000 mW / cm ^2.

The ink composition of the present invention is appropriately irradiated with such actinic radiation, for example, for 0.01 to 120 seconds, and preferably for 0.1 to 90 seconds.
Actinic radiation irradiation conditions and a basic irradiation method are disclosed in JP-A-60-132767. Specifically, the light source is provided on both sides of the head unit including the ink ejection device, and the head unit and the light source are scanned by a so-called shuttle method. Irradiation with actinic radiation takes a certain time (for example, 0.01 to 0.5 seconds, preferably 0.01 to 0.3 seconds, more preferably 0.01 to 0.15 seconds) after ink landing. Will be done. In this way, by controlling the time from ink landing to irradiation to an extremely short time, it is possible to prevent the ink that has landed on the recording medium from spreading before curing. Further, since the ink can be exposed to a porous recording medium before the ink penetrates to a deep part where the light source does not reach, residual unreacted monomer can be suppressed, and as a result, odor can be reduced. .
Further, the curing may be completed by another light source that is not driven. In WO99 / 54415, as an irradiation method, a method using an optical fiber or a method in which a collimated light source is applied to a mirror surface provided on the side surface of the head unit to irradiate the recording unit with UV light is disclosed.

By adopting the ink jet recording method as described above, the dot diameter of the landed ink can be kept constant even on various recording media having different surface wettability, and the image quality is improved. In addition, in order to obtain a color image, it is preferable to superimpose in order from a color with low brightness. By superimposing the inks in the order of low lightness, the irradiation line can easily reach the lower ink, and good curing sensitivity, reduction of residual monomers, reduction of odor, and improvement of adhesion can be expected. In addition, irradiation can be performed by discharging all colors and collectively exposing, but exposure for each color is preferable from the viewpoint of promoting curing.
Thus, the ink composition of the present invention is cured by irradiation with actinic radiation to form a hydrophobic image on the surface of the hydrophilic support.

(3-2) Inkjet recording apparatus There is no restriction | limiting in particular as an inkjet recording apparatus used for this invention, A commercially available inkjet recording apparatus can be used. That is, in the present invention, recording can be performed on a recording medium using a commercially available inkjet recording apparatus.
Examples of the ink jet recording apparatus that can be used in the present invention include an ink supply system, a temperature sensor, and an actinic radiation source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head has a multi-size dot of 1 to 100 pl, preferably 8 to 30 pl, for example, 320 × 320 to 4,000 × 4,000 dpi, preferably 400 × 400 to 1,600 × 1,600 dpi. More preferably, it can be driven so as to discharge at a resolution of 720 × 720 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

  As described above, since it is desirable that the radiation curable ink has a constant temperature for the ejected ink, heat insulation and heating can be performed from the ink supply tank to the inkjet head portion. The temperature control method is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors at each piping site and perform heating control according to the ink flow rate and the environmental temperature. The temperature sensor can be provided near the ink supply tank and the nozzle of the inkjet head. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of thermal energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

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

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples.

The compounds used in this example are described below.
(Pigment)
C pigment (cyan pigment): IRGALITETE BLUE GLVO (manufactured by Ciba Specialty Chemicals)
M pigment (magenta pigment): CINQUASIA MAGENTA RT-335 D (manufactured by Ciba Specialty Chemicals)
Y pigment (yellow pigment): NOVOPERM YELLOW H2G (manufactured by Clariant)
K pigment (black pigment): SPECIAL BLACK 250 (manufactured by Ciba Specialty Chemicals)
(Dispersant)
BYK168 (manufactured by BYK Chemie)

(Polyfunctional oxetane compound)
OXT-221 (manufactured by Toagosei Co., Ltd.)
Compound A: Compound having the following structure

(Polyfunctional oxirane compounds)
Cylacure UVR6105 (manufactured by Dow Chemical)
Celoxide 3000 (manufactured by Daicel Chemical Industries)

(Monofunctional oxetane compound)
Exemplary compound (1)
Exemplary compound (2)
Compound B: Compound having the following structure Compound C: Compound having the following structure

(Monofunctional oxirane compound)
Exemplary compound (20)
Exemplary compound (39)
(Polymerization initiator)
Esacure 1064 (manufactured by Lamberti)
(Additive)
TPM: Tripropylene glycol monomethyl ether (manufactured by Dow Chemical)
(Surfactant)
BYK307 (manufactured by BYK Chemie)

(Preparation of cyan mill base A)
IRGALITTE BLUE GLVO 300 parts by weight OX221 500 parts by weight BYK168 200 parts by weight The above components were stirred and mixed to obtain cyan mill base A. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 6 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of magenta mill base B)
CINQUASIA MAGENTA RT-335 D 300 parts by weight OX221 300 parts by weight BYK168 400 parts by weight The above components were stirred and mixed to obtain magenta mill base B. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 10 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of yellow mill base C)
NOVOPERM YELLOW H2G 300 parts by weight OX221 300 parts by weight BYK168 400 parts by weight The above components were stirred and mixed to obtain Yellow Mill Base C. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 10 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of black mill base D)
SPECIAL BLACK 250 300 parts by weight OX221 300 parts by weight BYK168 400 parts by weight The above components were stirred and mixed to obtain Black Mill Base D. The pigment mill base was prepared in a disperser motor mill M50 (manufactured by Eiger) and dispersed for 10 hours at a peripheral speed of 9 m / s using zirconia beads having a diameter of 0.65 mm.

(Preparation of ink)
Millbases A to D, the respective polysynthetic compounds, the polymerization initiator, and the additives were mixed according to the formulations shown in Table 1 and stirred at high speed to obtain an ink composition.

(Examples 2 to 20, Comparative Examples 1 to 7)
An ink composition was prepared in exactly the same manner except that each component used in Example 1 was changed as shown in the following table.

<Measurement of ink viscosity>
The viscosity of each ink composition prepared at 25 ° C. was measured using a B-type viscometer (LVDV-1, manufactured by Brookfield). The results are shown in Table 2.

<Inkjet image recording>
Next, recording on a recording medium was performed using a commercially available inkjet recording apparatus having a piezoelectric inkjet nozzle. The ink supply system was composed of an original tank, supply piping, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head, and heat insulation and heating were performed from the ink supply tank to the inkjet head portion. Temperature sensors were provided near the ink supply tank and the nozzles of the inkjet head, respectively, and temperature control was performed so that the nozzle portions were always 40 ° C. ± 2 ° C. The piezo-type inkjet head was driven so that 8 to 30 pl multi-size dots could be ejected at a resolution of 720 × 720 dpi. After landing, UV light was condensed to an exposure surface illuminance of 700 mW / cm ² , and the exposure system, main scanning speed, and ejection frequency were adjusted so that irradiation started 0.1 seconds after ink landed on the recording medium. Further, the exposure time was variable, and exposure energy was irradiated. A HAN250NL high-cure mercury lamp (manufactured by GS Yuasa Corporation) was used as the ultraviolet lamp. In the present invention, dpi represents the number of dots per 2.54 cm. As a recording medium, an ester film E5000 (thickness 125 μm, manufactured by Toyobo Co., Ltd.) was used.

<Evaluation of inkjet image>
Subsequently, the sensitivity, film flexibility, and storage stability required for curing were evaluated for each formed image according to the method described below.

(Measurement of curing sensitivity)
In accordance with the inkjet recording method, a solid image having an average film thickness of 12 μm was drawn, and the exposure energy amount (mJ / cm ² ) at which the tackiness disappeared on the image surface after ultraviolet irradiation was defined as the curing sensitivity. The smaller the value, the higher the sensitivity.
The curing sensitivity was evaluated according to the following criteria.
3 ··· 150mJ / cm ² or less ² ··· 150mJ / cm 2 Beyond 600mJ / cm ² less than 1 ··· 600mJ / cm ² or more

(Bending test)
As the recording medium, an ester film E5000 (film thickness 125 μm, manufactured by Toyobo Co., Ltd.) is used, the exposure energy is constant at 900 (mJ / cm ² ), and the average film thickness of the image area is 12 μm, 24 μm, and 36 μm. Three solid images were drawn. In the bending test, the recording material on which the image was formed was bent once at 25 ° C. and evaluated by the presence or absence of cracks in the image area. In general, when the average film thickness is increased, distortion applied to the image portion when the image portion is bent increases, and cracks are likely to occur. That is, by testing whether the image portion is cracked with a thicker film thickness, a measure of flexibility can be obtained.
The evaluation criteria are as follows.
4 ... No cracks occur in all samples having an average film thickness of 12 μm, 24 μm, and 36 μm.
3 ... Cracks do not occur in samples having an average film thickness of 12 μm and 24 μm, but cracks occur in the bent portion of the image portion in the sample having an average film thickness of 36 μm. .
2 ... Although cracks do not occur in the samples having an average film thickness of 12 μm, cracks occur in the bent portions of the image portions in the samples having an average film thickness of 24 μm and 36 μm.
1... Samples having average film thicknesses of 12 [mu] m, 24 [mu] m, and 36 [mu] m are cracked in the bent portion of the image portion.

(Evaluation of storage stability)
The prepared ink was stored at 75% RH and 60 ° C. for 3 days, then the ink viscosity at the ejection temperature was measured, and the increase in the ink viscosity was expressed as the viscosity ratio after storage / before storage. If the viscosity does not change and is close to 1.0, the storage stability is good, and if it exceeds 1.5, clogging may occur at the time of injection, which is not preferable.
Storage stability was evaluated according to the following criteria.
3 ... The viscosity ratio after storage / before storage is 1.0 or more and less than 1.20 2 ... The viscosity ratio after storage / before storage is 1.20 or more and less than 1.50 1 ... After / after storage The previous viscosity ratio is 1.50 or more.

(Examples 21 to 26, Comparative Examples 8 to 13)
<Inkjet image recording>
Next, recording on a recording medium was performed using a commercially available inkjet recording apparatus having a piezoelectric inkjet nozzle. The ink supply system was composed of an original tank, supply piping, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head, and heat insulation and heating were performed from the ink supply tank to the inkjet head portion. Temperature sensors were provided near the ink supply tank and the nozzles of the inkjet head, respectively, and temperature control was performed so that the nozzle portions were always 40 ° C. ± 2 ° C. The piezo-type inkjet head was driven so that 8 to 30 pl multi-size dots could be ejected at a resolution of 720 × 720 dpi. After landing, UV-LED light was condensed to an exposure surface illuminance of 300 mW / cm ² , and the exposure system, main scanning speed, and ejection frequency were adjusted so that irradiation started 0.1 seconds after ink landed on the recording medium. . Further, the exposure time was variable, and exposure energy was irradiated. NCCU033 (manufactured by Nichia Corporation) was used for the UV-LED lamp. In the present invention, dpi represents the number of dots per 2.54 cm. As a recording medium, an ester film E5000 (film thickness 125 μm, manufactured by Toyobo Co., Ltd.) was used.
The curability and flexibility tests were performed in the same manner as in Examples (1 to 20) except that the criteria for the curability test were as follows. The storage stability test was omitted because it is a characteristic of the ink itself. The results are shown in Table 3.
The curing sensitivity was evaluated according to the following criteria.
3 ··· 300mJ / cm ² or less ² ··· 300mJ / cm 2 Beyond 900mJ / cm ² less than 1 ··· 900mJ / cm ² or more

From Table 2 and Table 3, (a) polyfunctional oxetane compound of the present invention, (b) polyfunctional oxirane compound, (c) monofunctional oxetane compound having a high polar group and / or monofunctional oxirane compound having a high polar group The ink composition containing (d) a cationic polymerization initiator and (e) a colorant is highly sensitive to irradiation with radiation, and has high image quality in terms of image formation on paper. It can be seen that the image can be formed and the storage stability is also good.

Claims (9)

(A) a polyfunctional oxetane compound,
(B) a polyfunctional oxirane compound,
(C) a monofunctional oxetane compound having a highly polar group and / or a monofunctional oxirane compound having a highly polar group,
(D) a cationic polymerization initiator, and
(E) An ink composition comprising a colorant.   (C) A monofunctional oxetane compound having a highly polar group or a monofunctional oxirane compound having a highly polar group has an ester bond, a carbonate bond, a hydroxyl group, an amino group, a urethane bond, an amide bond, a urea bond, and a substituent. The ink composition according to claim 1, which has at least one selected from the group consisting of a bisphenoxy bond, a nitrogen-containing cyclic compound group, an oxygen-containing cyclic compound group, and an alkylene glycol structure.   (C) The ink composition according to claim 1 or 2, wherein the monofunctional oxetane compound having a highly polar group or the monofunctional oxirane compound having a highly polar group is a compound having 3 or more total oxygen atoms.   (C) The ink composition according to any one of claims 1 to 3, wherein the monofunctional oxetane compound having a highly polar group or the monofunctional oxirane compound having a highly polar group does not have a hydrogen bonding group. (C) A structure in which a monofunctional oxetane compound having a high polarity group or a monofunctional oxirane compound having a high polarity group has one 3-membered or 4-membered cyclic ether and is represented by the formula (1) The ink composition according to claim 1, which has a unit.

(In Formula (1), R ₁ represents an alkylene group, a cycloalkylene group, or an arylene group. N represents an integer of 1 or more.)   (C) The content of the monofunctional oxetane compound having a high polarity group and the monofunctional oxirane compound having a high polarity group is 5% by weight to 70% by weight of the whole ink, and the content of the polyfunctional oxetane compound is that of the whole ink. 10% by weight to 50% by weight, the content of the polyfunctional oxirane compound is 10% by weight to 50% by weight of the whole ink, and the total content of the polyfunctional oxirane compound and the polyfunctional oxetane compound is 20% of the whole ink. The ink composition according to any one of claims 1 to 5, which is in a range of from wt% to 70wt%.   The ink composition according to any one of claims 1 to 6, which is for inkjet recording. (A) a step of discharging the ink composition onto a recording medium; and (b) a step of irradiating the discharged ink composition with active radiation to cure the ink composition;
An inkjet recording method comprising:
The ink-jet recording method, wherein the ink composition is the ink composition according to any one of claims 1 to 7.   A printed matter recorded by the inkjet recording method according to claim 8.