JP2010018728A - Ink composition, inkjet recording method and printed material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition for inkjet recording, having high sensitivity to active radiation, excellent curability and excellent ejection stability and giving an image having excellent blocking resistance. <P>SOLUTION: The ink composition for inkjet recording contains (A) a polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton and a long-chain alkyl group and a radically polymerizable group on a side chain, (B) a sensitizing dye expressed by general formula (i), (C) a radically polymerizable compound different from the polymer (A), and (D) a radical polymerization initiator. In the formula (i), X is O, S or NR; R is a hydrogen atom, an alkyl group or an acyl group; n is 0 or 1; and R<SP>1</SP>to R<SP>8</SP>are each independently a hydrogen atom or a univalent substitution group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention mainly relates to an ink composition suitable for ink jet recording, an ink jet recording method using the ink composition, and a printed matter obtained by the ink jet recording method.

  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. For example, the ink jet method can be implemented with an inexpensive apparatus, and the ink can be used efficiently because the image is directly formed on the recording medium by ejecting the ink only to the required image portion. Cost is low. Furthermore, there is little noise and it is excellent as an image recording method.

According to the inkjet system, printing is possible not only on plain paper but also on non-water-absorbing recording media such as plastic sheets and metal plates. However, high speed and high image quality are important issues for printing. The time required for drying and curing the droplets after printing has a property of greatly affecting the productivity of printed matter and the sharpness of the printed image.
As one of the ink jet methods, there is a recording method using an ink jet ink that can be cured by irradiation of radiation. According to this method, the productivity of printing can be improved and a sharp image can be formed by irradiating the ink immediately after ink ejection or after a certain time and curing the ink droplets.
By achieving high sensitivity of inkjet inks that can be cured by irradiation with radiation such as ultraviolet rays, high curability is imparted to radiation, improving productivity of inkjet recording, reducing power consumption, and loading on the radiation generator There are many benefits, such as long life due to mitigation and prevention of volatilization of low molecular weight materials due to insufficient curing. Higher sensitivity is particularly important in improving the strength of the formed image.

Such a curable ink jet method using radiation, for example, ultraviolet rays, has been attracting attention in recent years because it has a relatively low odor, can be recorded on a recording medium having no quick-drying property, and no ink absorbability. A UV curable ink composition has been proposed (see, for example, Patent Document 1 to Patent Document 5).
In addition, as an ink composition having a high curing sensitivity and giving a good image quality, at least one hydrophobic polymer selected from the group consisting of a fluorine group-containing polymer, a long-chain alkyl group-containing polymer, and an alicyclic group-containing polymer Ink compositions containing the same are known (for example, see Patent Document 6).
However, these ink compositions have problems such as the stickiness of the formed image and the phenomenon that the low molecular weight component exudes from the image surface (so-called no-out) and the like, and the blocking resistance is insufficient. It was. Further, if a large amount of polyfunctional monomer is used in order to suppress the discharge, problems such as an increase in viscosity and a concern about ejection properties, and a cured film to be formed become brittle.

On the other hand, in ultraviolet curable ink compositions, benzyl, benzoin, benzoin ethyl ether, Michler's ketone, anthraquinone, acridine, phenazine, benzophenone, 2-ethylanthraquinone and the like have been generally used as photopolymerization initiators (for example, (Refer nonpatent literature 1.).
However, when these photopolymerization initiators are used, since the sensitivity of curing of the composition is low, a long time is required for image exposure in image formation. For this reason, when a fine image is formed, if there is a slight vibration in the operation, an image with good image quality cannot be reproduced, and the amount of energy emitted from the light source of the exposure must be increased. It was necessary to consider the radiation of the exothermic heat.
In general, as a method for increasing sensitivity to radiation in a radiation curable composition, use of various polymerization initiation systems is disclosed (Non-patent Document 1, Patent Document 7 to Patent Document 9). However, there is no example in which a polymerization initiating system satisfying sufficient sensitivity for scanning exposure is employed in ink.

In view of the above, an ink composition that can be cured with high sensitivity to radiation and can form an image excellent in blocking resistance has been desired.
JP-A-63-235382 JP-A-3-216379 Japanese Patent Laid-Open No. 5-214280 Japanese Patent Publication No.6-212256 Japanese Patent Publication No. 6-62905 JP 2006-182970 A Bruce M. Monroe (Bruce M. Monroe et al., Chemical Reviews), Vol. 93, (1993), p. 435-448. U.S. Pat. No. 4,134,813 JP-A-1-253731 JP-A-6-308727

  An object of the present invention is an inkjet ink composition that is highly sensitive to irradiation with actinic radiation, excellent in curability, excellent in ejection stability, and capable of forming an image excellent in blocking resistance. An object of the present invention is to provide an ink jet recording method using an ink composition and a printed matter obtained from the ink jet recording method.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by using a specific radical polymerizable polymer and a specific sensitizing dye in combination, and complete the ink composition of the present invention. It came to.

  That is, the inkjet ink composition of the present invention is a polymer having (A) a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group, and a radically polymerizable group in the side chain. And (B) a sensitizing dye represented by the following general formula (i), (C) a radical polymerizable compound different from the polymer of (A), and (D) a radical polymerization initiator. It is characterized by that.

In the general formula (i), X represents O, S, or NR, and R represents a hydrogen atom, an alkyl group, or an acyl group. n represents 0 or 1. R ^{1 to} R ⁸ each independently represent a hydrogen atom or a monovalent substituent. ^{Two of} R ¹ , R ² , R ³ , and R ⁴ may be connected to each other to form a ring. R ⁵ or R ⁶ and R ⁷ or R ⁸ may be linked to each other to form an aliphatic ring, but they do not form an aromatic ring.

In the inkjet ink composition of the present invention, it is one of the preferred embodiments that (E) a colorant is further contained.
In the present invention, the polymer (A) is one of the preferred embodiments in which the main chain structure is a polymer synthesized by radical chain polymerization, and the polymer (A) is a main chain structure. It is also a preferred embodiment that the polymer contains a urethane structure or a urea structure as a repeating unit.

The ink jet recording method of the present invention comprises (1) a step of ejecting the ink composition of the present invention onto a recording medium, and (2) irradiating the ejected ink composition with actinic radiation to produce the ink composition. And a step of curing the object.
The printed matter of the present invention is recorded by the ink jet recording method of the present invention.

About the effect | action of the inkjet ink composition of this invention, it estimates as follows.
In the present invention, the combination of the sensitizing dye that cures efficiently with a small addition amount and the polymer of (A) that suppresses the crying out of the low molecular component allows the crying out of the non-curing component after exposure. A cured product having an extremely low cross-linking density on the surface is obtained. As a result, the ink composition for inkjet is capable of forming a cured product with high sensitivity, excellent curability, and excellent flexibility. Furthermore, since the solubility of the sensitizing dye is good, nozzle clogging is difficult to occur, and the addition of the polymer (A) can also improve the wettability with respect to the nozzle plate required for ejection. It is considered that the ink-jet ink composition of the invention can realize stable ejection properties.

  According to the present invention, an inkjet ink composition that has high sensitivity to irradiation with actinic radiation, excellent curability, excellent ejection stability, and can form an image excellent in blocking resistance, and the inkjet An ink jet recording method using the ink composition, and a printed matter obtained from the ink jet recording method can be provided.

[Inkjet ink composition]
The inkjet ink composition of the present invention comprises (A) a polymer having a side chain having a radically polymerizable group and a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group; (B) a sensitizing dye represented by the general formula (i), (C) a radical polymerizable compound different from the polymer (A), and (D) a radical polymerization initiator. And
Hereinafter, essential components constituting the inkjet ink composition of the present invention (hereinafter sometimes simply referred to as “ink composition”) will be described.

<(A) Polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group, and a radically polymerizable group in the side chain>
The ink composition of the present invention comprises (A) a polymer having a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group, and a radically polymerizable group in the side chain (hereinafter, And appropriately referred to as “surface segregation polymer”).

The surface segregation polymer in the present invention is a polymer containing in its side chain a partial structure selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group.
Hereinafter, the partial structures 1) to 3) will be described.

[1] Fluorine-substituted hydrocarbon group]
The fluorine-substituted hydrocarbon group in the surface segregation polymer in the present invention may be a hydrocarbon group substituted with at least one fluorine atom. For example, at least one hydrogen atom in an alkyl group or an alkylene group may be a fluorine atom. A substituted fluoroalkyl group and a fluoroalkylene group can be mentioned, and a perfluoroalkyl group and a perfluoroalkylene group in which all hydrogens of the alkyl group and the alkylene group are substituted with fluorine are more preferable, and a perfluoroalkyl group is still more preferable.

As an alkyl group, C3-C12 is preferable, C4-C10 is more preferable, and C6-C8 is still more preferable.
As an alkylene group, C2-C12 is preferable, C4-C10 is more preferable, and C6-C8 is still more preferable.

Specific embodiments of the fluorine-substituted hydrocarbon group in the present invention will be described.
Preferred fluorine-substituted hydrocarbon groups possessed by the surface segregation polymer include those shown in the following (A) or (B).
(A) A substituent derived from a fluoroaliphatic compound produced by a telomerization method or an oligomerization method (hereinafter, appropriately referred to as “fluoroaliphatic group”)
(B) Substituent represented by the following (general formula I)

In the above (general formula I), R ² and R ³ are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, X is a covalent bond or a divalent linking group (organic group), and m is 0 or more. N represents an integer of 1 or more.
When m is 2 or more, functional groups on adjacent carbons (that is, R ² and R ³ bonded to adjacent carbons) may be bonded to form an aliphatic ring. .
The substituent represented by (general formula I) is connected to the polymer main chain at the portion *.

(A) Substituent derived from fluoroaliphatic compound produced by telomerization method or oligomerization method The fluorine-substituted hydrocarbon group in the present invention is a telomerization method (also called telomer method) or oligomerization. A substituent (fluoroaliphatic group) derived from a fluoroaliphatic compound produced by the method (also referred to as oligomer method) is preferred.
With regard to a method for producing such a fluoroaliphatic group, for example, “Synthesis and Function of Fluorine Compound” (Supervision: Nobuo Ishikawa, Issue: CMC Co., 1987), “Chemistry of Organic Fluorine” Compounds II "(Monograph 187, Ed by Milos Hudricky and Attila E. Pavlath, American Chemical Society 1995), pages 747-752.

The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen.
As a specific example, Synthesis Example 1 below is shown.

  The obtained terminal iodinated telomer is usually subjected to appropriate terminal chemical modification as in, for example, Synthesis Example 2 below, and led to a fluoroaliphatic compound. These compounds are further converted into a desired monomer structure as necessary, and used for the production of a polymer having a fluoroaliphatic group in the side chain such as the surface segregation polymer in the present invention.

In the present invention, the fluoroaliphatic compound synthesized by the telomer method is preferably a fluoroaliphatic compound represented by the following general formula [TM-1].
By using such a fluoroaliphatic compound as it is or converted into a desired monomer structure, it can be introduced into the fluorine-substituted hydrocarbon group in the surface segregation polymer in the present invention.

In the above general formula [TM-1], T is one group selected from the following (Group T), Z is one group selected from the following (Group Z), and n is an integer of 0 to 20. To express.
When the fluoroaliphatic compound represented by the general formula [TM-1] has a polymerizable group such as a double bond in Z, it should be used as a copolymerization component when synthesizing the surface segregation polymer in the present invention. Can do.

  In the above general formula [TM-1], when the group represented by Z is one group selected from the following (Group Z ′), a structure having an acryloyl group or a methacryloyl group at the molecular terminal Become. For this reason, since the surface segregation polymer in this invention is obtained from the fluoro aliphatic compound represented by general formula [TM-1] simply by vinyl polymerization, it is especially preferable.

  Specific examples of the compound produced by the telomer method, which is preferably used when synthesizing the surface segregation polymer in the present invention (commercially available based on a fluoroaliphatic compound represented by the general formula [TM-1]) Product), for example, fluorine chemical products A-1110, A-1210, A-1310, A-1420, A-1620, A-1820, A-2020 sold by Daikin Chemicals Sales Co., Ltd. , A-1260, A-1460, A-1660, A-1860, A-1435, A-1635, A-1835, A-1473, A-1637, A-1837, A-1514, A-3420, A -3620, A-3820, A-4020, A-3260, A-3460, A-3660, A-3860, A-3737, A-3737, A-5210, -5410, A-5610, A-5810, A-7110, A-7210, A-7310, A-9210, C-1100, C-1200, C-1300, C-1400, C-1500, C-1600 , C-1700, C-1800, C-1900, C-2000, C-5200, C-5400, C-5600, C-5800, C-5208, C-5408, C-5608, C-6008, C -8200, C-8300, C-8500, C-9111, C-8208, C-8308, C-8508, C-9216, E-1430, E-1630, E-1830, E-2030, E-3430 , E-3630, E-3830, E-4030, E-5244, E-5444, E-5644, E-5844, F-1420, F-1620, F-18 0, F-2020, I-1200, I-1300, I-1400, I-1600, I-1700, I-1800, I-2000, I-1420, I-1620, I-1820, I-2020, I-3200, I-3400, I-3600, I-3800, I-4000, I-3620, I-3820, I-4020, I-5200, I-5400, I-5600, I-8208, I- 8207, I-8407, I-8607, M-1110, M-1210, M-1420, M-1620, M-1820, M-2020, M-3420, M-3620, M-3820, M-4020, M-3433, M-3633, M-3833, M-4033, M-5210, M-5410, M-5610, M-5810, M-6010, M-7210, M- 7310, R-1110, R-1210, R-1420, R-1620, R-1820, R-2020, R-1433, R-1633, R-1833, R-3420, R-3620, R-3820, R-4020, R-3433, R-5210, R-5410, R-5610, R-5810, 6010, R-7210, R-7310, U-1310, U-1710, and Nippon Mektron Co., Ltd. CHEMINOX FA, FA-M, FAAC, FAAC-M, FAMAC, FAMAC-M and the like manufactured by

  The fluoroaliphatic compound produced by the telomer method can easily synthesize a polymer having a fluoroaliphatic group in the side chain, such as the surface segregation polymer in the present invention, by a method known to those skilled in the art. .

In the present invention, a substituent derived from a fluoroaliphatic compound produced by an oligomerization method (oligomer method) is also preferred.
The oligomerization method is a method for producing an oligomer by cationic polymerization of tetrafluoroethylene in a polar solvent such as diglyme using potassium fluoride or cesium fluoride as a catalyst. As a specific example, Synthesis Example 3 below is shown.
Fluoroaliphatic compounds obtained by the oligomer method, like the compounds by the telomer method described above, use a polymerizable group (unsaturated bond) in the oligomer obtained by cationic polymerization, and if necessary, appropriate chemical modification Then, a polymer having a substituent (fluorine-containing hydrocarbon group) derived from the fluoroaliphatic compound in the side chain can be synthesized.

(B) Substituent Represented by (General Formula I) The surface segregation polymer in the invention preferably has a substituent represented by the following (general formula I) from the viewpoint of uneven distribution on the ink surface.

In the above (general formula I), R ² and R ³ each represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, * represents a linking site to a polymer chain, and X represents a covalent bond or a divalent linking group. , M represents an integer of 0 or more, and n represents an integer of 1 or more.
When m is 2 or more, functional groups on adjacent carbons (that is, R ² and R ³ bonded to adjacent carbons) may be bonded to form an aliphatic ring. .

  Among the substituents represented by the above (General Formula I), those in which “n” in (General Formula I) is 1 to 10 are preferable, 1 to 4 are more preferable, 2 or 3 It is particularly preferred that

  That is, as the surface segregation polymer in the present invention, the structure of the side chain portion bonded to the polymer main chain is a structure represented by the following (general formula IB), and in particular, n = 2, 3, It is preferable because it exhibits very good performance.

In the above (formula ^{IB), R 2, R 3} , X, m, and n have the same meanings as ^{R 2, R 3, X,} m, and n in both (general formula I).

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ² and R ³ in (General Formula I) and (General Formula IB) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, An isobutyl group, a tert-butyl group, etc. are mentioned, Preferably they are a hydrogen atom or a methyl group, More preferably, it is a hydrogen atom.

In (General Formula I) and (General Formula IB), when X is a covalent bond, it means that the polymer main chain and the carbon atom to which R ² and R ³ are bonded are directly linked. To do.
When X is a divalent linking group, examples of the linking group include —O—, —S—, —N (R ⁴ ) —, —CO—, and the like. Among these, -O- is more preferable.
Here, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group, and a hydrogen atom and a methyl group are preferable.

In (General Formula I) and (General Formula IB), m represents an integer of 0 or more, preferably an integer of 2 to 8, and particularly preferably 2. Further, when m is 2 or more, functional groups on adjacent carbons (that is, R ² or R ³ bonded to adjacent carbons) may be bonded to form an aliphatic ring. .

  In (General Formula I) and (General Formula IB), n represents an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 4, and particularly preferably 2 or 3.

In (General Formula I), * represents a linking site with a polymer main chain, and specific examples of the polymer main chain include the following examples.
For example, acrylic resin, methacrylic resin, styryl resin, polyester resin, polyurethane resin, polycarbonate resin, polyamide resin, polyacetal resin, phenol / formaldehyde condensation resin, polyvinylphenol resin, maleic anhydride / α-olefin resin, α-hetero substituted A methacrylic resin or the like can be used. Among these, acrylic resins, methacrylic resins, styryl resins, polyester resins, and polyurethane resins are useful, and acrylic resins, methacrylic resins, and polyurethane resins are particularly useful.

  The surface segregation polymer having 1) a fluorine-substituted hydrocarbon group in the present invention has, for example, the above-mentioned monomer (A) having a fluoroaliphatic group or (B) the substituent represented by the above (general formula I). A monomer (that is, a monomer having a fluorine-substituted hydrocarbon group) is appropriately selected and used, and can be easily obtained by methods known to those skilled in the art, such as condensation polymerization, addition polymerization, and ring-opening polymerization. Further, these monomers may be mixed as necessary.

(Monomer having a fluorine-substituted hydrocarbon group)
In the present invention, as described above, it is preferable to obtain a surface segregation polymer by using a monomer having a fluorine-substituted hydrocarbon group (hereinafter referred to as a fluorine-substituted hydrocarbon group-containing monomer).
Preferred examples of the fluorine-substituted hydrocarbon group-containing monomer include monomers represented by the following (General Formula II).

In (General Formula II), R ¹ represents a hydrogen atom, a halogen atom, an optionally substituted methyl group, or an optionally substituted ethyl group. ^{Further, R 2, R 3, X,} m, and n are both the same meaning as ^{R 2, R 3, X,} m, and n in (formula I), and their preferable examples are also the same.

In addition, examples of the halogen atom represented by R ¹ in (General Formula II) include a fluorine atom, a chlorine atom, and a bromine atom.

  Specific examples of the monomer represented by (General Formula II) used in the present invention are shown below.

  As a monomer used for the synthesis of the surface segregation polymer in the present invention, among the monomers represented by the above (General Formula II), “n” in (General Formula II) is preferably 1 to 10, and 1 to 4 Is more preferable, and 2 or 3 is particularly preferable.

[2] Siloxane skeleton
The siloxane skeleton contained in the surface segregation polymer in the present invention is not particularly limited as long as it has “—Si—O—Si—”.
In the present invention, the surface segregation polymer having a siloxane skeleton is represented by the following structural formula (A) from the viewpoint of increasing the ejection stability of the ink composition and increasing the surface segregation property when the ink composition is used as a coating film. It is preferably a polymer obtained by polymerizing a compound represented (hereinafter also referred to as “specific siloxane compound”).
In the structural formula (A), R ¹ is a linking group between a Si atom of a siloxane bond and X or Y.

In the structural formula (A), R ¹ represents a linear or branched alkylene group having 2 to 6 carbon atoms which may have a substituent such as a hydroxyl group, an amine group, or a halogen atom, or the following structural formula (B ) Represents a divalent linking group.

In the structural formula (B), R ² represents a hydrogen atom or a methyl group, and n represents an integer of 1 to 50. Here, two or more R ² exist in the structural formula (B), but they may be different or the same.

In the structural formula (A), x ¹ , x ² , and x ³ are integers whose sum satisfies 1 to 100.
Further, ^{y 1} is an integer of 1 to 30.
In the structural formula (A), X is a single bond or a divalent group represented by the following structural formula (C).

In the structural formula (C), R ³ represents a linear or branched alkylene group having 1 to 6 carbon atoms which may have a substituent such as a hydroxyl group, an amine group, or a halogen atom, and Z ¹ and Z ² represents an oxygen atom, a sulfur atom, or —NR ⁴ —, and Z ¹ and Z ² may be different from each other or the same. R ⁴ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
In the structural formula (C), Z ² is bonded to R ¹ in the structural formula (A).

  In the structural formula (A), Y represents a monovalent group represented by the following structural formula (D) to the following structural formula (F).

In the structural formulas (D) to (F), R ⁵ represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms.
R ⁶ represents a linear or branched alkylene group having 2 to 10 carbon atoms, and R ⁷ represents a linear or branched alkylene group having 1 to 6 carbon atoms.

  In the structural formula (A), Z represents a monovalent group represented by the following structural formula (G).

In the structural formula (G), R ⁶ represents an unsubstituted alkyl group having 1 to 4 carbon atoms, y ¹ represents an integer of ¹ to 100, preferably an integer of 1 to 50, more preferably 1 to 20 Is an integer.

[3] Long chain alkyl group]
The 3) long-chain alkyl group contained in the surface-segregating polymer in the present invention refers to a substituent represented by -C n _H 2n _{+ 1} in the structural unit represented by the following general formula (1). This long-chain alkyl group is preferably introduced into the polymer in a state of being linked to Y constituting the polymer main chain as in the structural unit represented by the following general formula (1).

In the general formula (1), n represents an integer of 6 to 40, preferably an integer of 10 to 30, and particularly preferably an integer of 12 to 20 from the viewpoint of surface segregation.
Y represents a trivalent linking group that constitutes a polymer main chain and is linked to a long-chain alkyl group.
What is preferable as such a structural unit represented by the general formula (1) is shown in the following general formula (1-2), but the present invention is not limited thereto.

In said general formula (1-2), n represents the integer of 6-40. W represents a divalent linking group, and Z ¹ , Z ² , and Z ³ each independently represent a hydrogen atom or a monovalent substituent.

The structural unit represented by the general formula (1-2) may have a plurality of long-chain alkyl groups. In that case, the long-chain alkyl group may be bonded to the Z ¹ or Z ³ position via the linking group W. The coupling | bonding group W has a branched structure, and the aspect which another long-chain alkyl group has connected with the front-end | tip can be taken.

As W in the general formula (1-2), a linear or branched, chain or cyclic alkylene group having 1 to 20 carbon atoms, a linear or branched chain or cyclic alkenylene group having 2 to 20 carbon atoms, C2-C20 alkynyl group, C6-C20 arylene (monocyclic, heterocyclic) group, -OC (= O)-, -OC (= O) Ar-, -OC (= O) O- , -OC (= O) OAr - , - C (= O) NR -, - C (= O) NAr -, - SO 2 NR -, - SO 2 NAr -, - O- ( alkyleneoxy, polyalkyleneoxy -OAr-aryleneoxy, polyaryleneoxy), -C (= O) O-, -C (= O) O-Ar-, -C (= O) Ar-, -C (= O) _{-, - SO 2 O -,} - SO 2 OAr -, - OSO 2 -, - OSO 2 Ar -, - NRSO 2 -, _{NArSO 2 -, - NRC (=} O) -, - NArC (= O) -, - NRC (= O) O -, - NArC (= O) O -, - OC (= O) NR -, - OC ( = O) NAr -, - NAr -, - NR -, - N + RR '-, - N + RAr -, - N + ArAr' -, - S -, - SAr -, - ArS-, Hajime Tamaki ( Examples of the hetero atom include at least one or more of nitrogen, oxygen, sulfur and the like, a 3-membered to 12-membered monocyclic or condensed ring, -OC (= S)-, -OC (= S) Ar-. , -C (= S) O-, -C (= S) OAr-, -C (= S) OAr-, -C (= O) S-, -C (= O) SAr-, -ArC (= O)-, -ArC (= O) NR-, -ArC (= O) NAr-, -ArC (= O) O-, -ArC (= O) O-, -ArC (= O) S-,- A C (= S) O -, - ArO -, - ArNR- and the like.
R and R ′ are each independently a hydrogen atom, a linear or branched alkyl group, a chain or cyclic alkyl group, a linear or branched alkenyl group, a chain or cyclic alkenyl group, or a linear chain. Alternatively, it represents a branched alkynyl group or a chain or cyclic alkynyl group, and Ar and Ar ′ each independently represents an aryl group.

  Among these linking groups, W includes an arylene (monocyclic, heterocyclic) group having 6 to 20 carbon atoms, —C (═O) NR—, —C (═O) NAr—, —O— ( Alkyleneoxy, including polyalkyleneoxy), —OAr— (aryleneoxy, polyaryleneoxy), —C (═O) O—, —C (═O) O—Ar—, —C (═O) —, -C (= O) Ar-, -S-, -SAr-, -ArS-, -ArC (= O)-, -ArC (= O) O-, -ArC (= O) O-, -ArO- , -ArNR- and the like, preferably an arylene (monocyclic, heterocyclic) group having 6 to 20 carbon atoms, -C (= O) NR-, -C (= O) NAr-, -O- (alkyleneoxy, poly Alkyleneoxy), -OAr- (aryleneoxy, polyaryleneoxy), -C (= O) O-,- (═O) O—Ar—, —SAr—, —ArS—, —ArC (═O) —, —ArC (═O) O—, —ArC (═O) O—, —ArO—, —ArNR— Etc. are more preferable.

  In the present invention, the linking group represented by W may be a combination of two or more of the linking groups listed here.

In General Formula (1-2), Z ¹ , Z ² , and Z ³ are each independently a hydrogen atom, a linear or branched, linear or cyclic alkyl group having 1 to 20 carbon atoms (for example, methyl , Ethyl, propyl, heptafluoropropyl, isopropyl, butyl, t-butyl, t-pentyl, cyclopentyl, cyclohexyl, octyl, 2-ethylhexyl, dodecyl, etc.), straight or branched, chained or cyclic having 2 to 20 carbon atoms Alkenyl groups (for example, vinyl, 1-methylvinyl, cyclohexen-1-yl, etc.), C2-C20 alkynyl groups (for example, ethynyl, 1-propynyl, etc.), C6-C20 aryl groups (for example, Phenyl, naphthyl, anthryl, etc.), C1-C20 acyloxy groups (for example, acetoxy, tetradecanoyloxy, benzoylo) ), C2-C20 alkoxycarbonyloxy group (e.g., methoxycarbonyloxy group, 2-methoxyethoxycarbonyloxy group, etc.), C7-C20 aryloxycarbonyloxy group (e.g., phenoxycarbonyloxy group). Etc.), a carbamoyloxy group having 1 to 20 carbon atoms (for example, N, N-dimethylcarbamoyloxy etc.), a carbonamido group having 1 to 20 carbon atoms (for example, formamide, N-methylacetamide, acetamide, N-methylformamide) , Benzamide, etc.), a sulfonamide group having 1 to 20 carbon atoms (for example, methanesulfonamide, dodecane sulfonamide, benzenesulfonamide, p-toluenesulfonamide, etc.), a carbamoyl group having 1 to 20 carbon atoms (for example, N -Methylcarbamoyl, N, N-di Ethylcarbamoyl, N-mesylcarbamoyl, etc.), C 0-20 sulfamoyl groups (for example, N-butylsulfamoyl, N, N-diethylsulfamoyl, N-methyl-N- (4-methoxyphenyl) sulfamoyl) Etc.), an alkoxy group having 1 to 20 carbon atoms (for example, methoxy, propoxy, isopropoxy, octyloxy, t-octyloxy, dodecyloxy, 2- (2,4-di-t-pentylphenoxy) ethoxy, polyalkylene Oxy, etc.), aryloxy groups having 6 to 20 carbon atoms (for example, phenoxy, 4-methoxyphenoxy, naphthoxy, etc.), aryloxycarbonyl groups having 7 to 20 carbon atoms (for example, phenoxycarbonyl, naphthoxycarbonyl, etc.),

C2-C20 alkoxycarbonyl group (for example, methoxycarbonyl, t-butoxycarbonyl, etc.), C1-C20 N-acylsulfamoyl group (for example, N-tetradecanoylsulfamoyl, N-benzoyl) Sulfamoyl and the like), N-sulfamoylcarbamoyl group having 1 to 20 carbon atoms (for example, N-methanesulfonylcarbamoyl group and the like), alkylsulfonyl group having 1 to 20 carbon atoms (for example, methanesulfonyl, octylsulfonyl, 2 -Methoxyethylsulfonyl, 2-hexyldecylsulfonyl, etc.), arylsulfonyl groups having 6 to 20 carbon atoms (for example, benzenesulfonyl, p-toluenesulfonyl, 4-phenylsulfonylphenylsulfonyl, etc.), alkoxycarbonyl having 2 to 20 carbon atoms. Amino groups (eg ethoxycal Nylamino, etc.), C7-20 aryloxycarbonylamino groups (eg, phenoxycarbonylamino, naphthoxycarbonylamino, etc.), C0-20 amino groups (eg, amino, methylamino, diethylamino, diisopropylamino, anilino) , Morpholino, etc.), an ammonio group having 3 to 20 carbon atoms (for example, trimethylammonio group, dimethylbenzylammonio group, etc.), cyano group, nitro group, carboxyl group, hydroxy group, sulfo group, mercapto group, carbon number 1 -20 alkylsulfinyl groups (for example, methanesulfinyl, octanesulphinyl, etc.), arylsulfinyl groups having 6-20 carbon atoms (for example, benzenesulfinyl, 4-chlorophenylsulfinyl, p-toluenesulfinyl, etc.), C1-20 Alkylthio group (eg, methylthio, octylthio, cyclohexylthio, etc.), arylthio group having 6-20 carbon atoms (eg, phenylthio, naphthylthio, etc.), ureido group having 1-20 carbon atoms (eg, 3-methylureido, 3, 3 -Dimethylureido, 1,3-diphenylureido, etc.), a C2-C20 heterocyclic group (the hetero atom includes, for example, at least one nitrogen, oxygen, sulfur, etc., a 3- to 12-membered monocyclic ring) A condensed ring such as 2-furyl, 2-pyranyl, 2-pyridyl, 2-thienyl, 2-imidazolyl, morpholino, 2-quinolyl, 2-benzimidazolyl, 2-benzothiazolyl, 2-benzoxazolyl, etc.) , An acyl group having 1 to 20 carbon atoms (for example, acetyl, benzoyl, trifluoroacetyl, etc.), 0 to carbon atoms 20 sulfamoylamino groups (for example, N-butylsulfamoylamino, N-phenylsulfamoylamino, etc.), silyl groups having 3 to 50 carbon atoms (for example, trimethylsilyl, dimethyl-t-butylsilyl, triphenylsilyl) Etc.), an azo group, and a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, etc.).
In addition, when Z ^{1 to} Z ³ are not hydrogen atoms, halogen atoms, or the like other than those that cannot further have a substituent, these may further have a substituent. Examples of the substituent As such, the substituents mentioned in the above specific examples can be mentioned.

As the ^Z 1 to Z ^3, independently, a hydrogen atom, a straight-chain or branched having 1 to 20 carbon atoms, chain or cyclic alkyl group, an aryl group having 6 to 20 carbon atoms, having 1 to 20 carbon atoms Acyloxy group, C1-20 carbonamido group, C1-20 alkoxy group, C6-20 aryloxy group, C7-20 aryloxycarbonyl group, C2-20 alkoxy A carbonyl group, an amino group having 0 to 20 carbon atoms, a cyano group, a hydroxy group, and a halogen atom are preferable, a hydrogen atom, a linear or branched, chain or cyclic alkyl group having 1 to 20 carbon atoms, and 6 to 20 carbon atoms. An aryloxy group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aryloxycarbonyl group having 7 to 20 carbon atoms, and 2 carbon atoms 20 alkoxycarbonyl group, an amino group having 0 to 20 carbon atoms, a cyano group, a halogen atom is more preferable.

  The structural unit represented by the general formula (1-2) is preferably a structural unit represented by the following general formula (1-3) from the viewpoint of segregation on the ink surface.

In the general formula (1-3), n represents an integer of 6 to 40, and R represents a hydrogen atom or a methyl group.
W is synonymous with W in the general formula (1-2).
Specific examples of the divalent substituent represented by W in the structural unit represented by the general formula (1-3) are shown below in terms of segregation on the ink surface. It is not limited to these.

Z ¹ has the same meaning as ^{Z 1} in the general formula (1-2).
Hereinafter, specific examples of Z ¹ in the structural unit represented by the general formula (1-3) are particularly preferable from the viewpoint of stable solubility in the ink composition, but the present invention is not limited thereto. Absent.

  Here, although the specific example of the structural unit which has the long-chain alkyl group which comprises the surface segregation polymer in this invention is given below, this invention is not limited to these.

In the present invention, the content in the surface segregation polymer of the partial structure selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group is 3% by mass to 60% by mass, respectively. % Is preferable, more preferably 3% by mass to 50% by mass, and still more preferably 5% by mass to 40% by mass.
By setting it as the above range, the surface segregation polymer can be efficiently segregated in the ink composition.

  In addition, the total content of specific sites in the case of containing two or more partial structures selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group depends on the surface segregation polymer. On the other hand, they are 3 mass%-60 mass%, More preferably, they are 3 mass%-50 mass%, More preferably, they are 5 mass%-40 mass%.

  The content of the partial structure selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group in the total solid content of the ink composition in the present invention is 0.1 mass. % To 20% by mass is preferable, more preferably 0.5% to 15% by mass, and still more preferably 1% to 10% by mass. By setting it as the said range, it is excellent in surface curability and blocking suppression, and the surface tension (22 mN / m-28 mN / m) and moderate viscosity which can be discharged are obtained.

[Radically polymerizable group]
The surface segregation polymer in this invention has a radically polymerizable group in a side chain.
When the surface segregation polymer contains a radical polymerizable group, the curability of the ink composition is improved, the surface stickiness is suppressed, and the blocking property is improved.

Examples of the radical polymerizable group include a polymerizable group having an ethylenically unsaturated bond capable of radical polymerization.
Examples of polymerizable groups having an ethylenically unsaturated bond capable of radical polymerization include acrylic acid ester groups, methacrylic acid ester groups, itaconic acid ester groups, crotonic acid ester groups, isocrotonic acid ester groups, and maleic acid ester groups. Examples thereof include radically polymerizable groups such as unsaturated carboxylic acid ester groups and styrene groups. Among these, a methacrylic acid ester group and an acrylic acid ester group are preferable.

  The content of the radical polymerizable group is preferably 5 mol% to 90 mol% in the surface segregation polymer, more preferably 5 mol% to 85 mol%, still more preferably 10 mol% to 80 mol%.

  As a method for introducing a radically polymerizable group into a surface segregation polymer, a monomer in which a reaction is blocked with a double bond of a radically polymerizable group using a protective group, this monomer is copolymerized, and the protective group is removed. Examples thereof include a method of forming a radical polymerizable group (double bond) and a method of introducing a low molecular compound having a radical polymerizable group into a surface segregation polymer by a polymer reaction.

The surface segregation polymer in the present invention is a copolymer having a partial structure selected from the group consisting of 1) a fluorine-substituted hydrocarbon group, 2) a siloxane skeleton, and 3) a long-chain alkyl group, and a structure other than a radical polymerizable group. A component (other copolymerization component) may be included. The other copolymer component is preferably used in the surface segregation polymer from the viewpoint of improving the solubility in the ink composition and improving the blocking property by controlling the polymer Tg.
The other copolymerization component is not particularly limited as long as it is derived from a radically polymerizable monomer, but from the viewpoint of copolymerization performance and solubility of the produced polymer in the ink composition, a monomer having an unsaturated double bond. Among them, acrylate or methacrylate is preferable. The preferable content of the other copolymerization component in the surface segregation polymer is 0 mol% to 70 mol%, more preferably 0 mol% to 50 mol%, and most preferably 0 mol% to 30 mol%.

Here, a preferred embodiment as a main chain structure of the surface segregation polymer contained in the ink composition of the present invention is a methacrylic resin or an acrylic resin.
In addition, the main chain structure of the surface segregation polymer is preferably synthesized by radical chain polymerization, and the main chain structure is a polymer containing a urethane structure or a urea structure as a repeating unit. Is also a preferred embodiment.

  The weight average molecular weight of the surface segregation polymer is preferably 3,000 to 200,000, more preferably 5,000 to 100,000, and still more preferably 10,000 to 80,000. By setting it as the said range, moderate viscosity is obtained and it is favorable from a viewpoint of handling property and blocking suppression.

  Below, the preferable specific example (a-1 to a-22) of the surface segregation polymer in this invention is given. The present invention is not limited to these specific examples.

  The content of the surface segregation polymer contained in the ink composition of the present invention is preferably 0.2% by mass to 5% by mass and more preferably 0.2% by mass to 3% by mass in the total solid content of the ink composition. 0.2 mass% to 1.5 mass% is more preferable.

<(B) Sensitizing dye represented by formula (i)>
The ink composition of the present invention contains a sensitizing dye in order to promote decomposition of the polymerization initiator by irradiation with actinic rays. The sensitizing dye is represented by the general formula (i) described in detail below. A sensitizing dye (hereinafter referred to as “specific sensitizing dye”) is contained as an essential component.
In general, a sensitizing dye absorbs specific actinic radiation and enters an electronically excited state. The sensitizing dye in an electronically excited state is brought into contact with the polymerization initiator to cause actions such as electron transfer, energy transfer, and heat generation, thereby causing a chemical change of the polymerization initiator, that is, decomposition, radical, acid or base. The generation of active species such as these causes the active species generated here to cause and accelerate the polymerization and curing reaction of the polymerizable compound described later.

As the sensitizing dye, a compound corresponding to the wavelength of actinic radiation that generates an initiating species in the polymerization initiator used in the ink composition may be used, but it should be used for a curing reaction of a general ink composition. In view of the above, examples of preferable sensitizing dyes include those having an absorption wavelength in the 350 nm to 450 nm region.
The ink composition of the present invention is required to contain a sensitizing dye (specific sensitizing dye) represented by the following general formula (i).

In the general formula (i), X represents O, S, or NR, and R represents a hydrogen atom, an alkyl group, or an acyl group. n represents 0 or 1. R ^{1 to} R ⁸ each independently represent a hydrogen atom or a monovalent substituent. ^{Two of} R ¹ , R ² , R ³ , and R ⁴ may be connected to each other to form a ring. R ⁵ or R ⁶ and R ⁷ or R ⁸ may be linked to each other to form an aliphatic ring, but they do not form an aromatic ring.

In general formula (i), X is preferably O or S, more preferably S.
Here, when n is 0, (CR ⁷ R ⁸ ) does not exist, and X and a carbon atom bonded to R ⁵ and R ⁶ are directly bonded to form a 5-membered heterocyclic ring containing X. Will be composed.

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom or a monovalent substituent.
When R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ represent a monovalent substituent, the monovalent substituent includes a halogen atom, an 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, aryloxy Carbonylamino group, imide group, heterocyclic thio group, sulfinyl group, phosphoryl group, acyl Group, and a carboxyl group, or sulfo group, and among them, preferably, an alkyl group, an alkoxy group, a halogen atom.

In addition, as R < ¹ >, R < ² >, R < ³ >, R < ⁴ >, R < ⁵ >, R < ⁶ >, R < ⁷ > and R < ⁸ > in General Formula (i) represents a monovalent substituent, the alkyl group has 1 carbon atom. 10 to 10 alkyl groups are preferable, and those having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group and t-butyl group are more preferable.
Similarly, alkoxy groups include those having 1 to 4 carbon atoms such as methoxy, ethoxy, hydroxyethoxy, propoxy, n-butoxy, isobutoxy, sec-butoxy, and t-butoxy. Preferably mentioned.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

R ¹ , R ² , R ³ , and R ⁴ may be bonded to each other, for example, fused together to form a ring.
Examples of the ring structure in the case where these form a ring include a 5- to 6-membered aliphatic ring and an aromatic ring, and may be a heterocyclic ring containing an element other than a carbon atom, or may be formed. The rings may be further combined to form a binuclear ring, for example, a condensed ring. Furthermore, these ring structures may further have a substituent exemplified in the case where R ^{1 to} R ⁸ represent a monovalent substituent in the general formula (i). N, O, and S can be mentioned as an example of a hetero atom in case the formed ring structure is a heterocyclic ring.

When n = 1, R ⁵ or R ⁶ and R ⁷ or R ⁸ may be connected to each other to form an aliphatic ring, but do not form an aromatic ring. The formed aliphatic ring is preferably a 3- to 6-membered ring, more preferably a 5-membered ring or a 6-membered ring.

  Examples of the sensitizing dye that can be used more suitably include compounds represented by the following general formula (iA).

In the general formula (iA), X represents O or S. n represents 0 or 1. R ^1A , R ^2A , R ^3A , R ^4A , R ^5A , R ^6A , R ^7A , and R ^8A are each independently a hydrogen atom, alkyl group, halogen atom, hydroxyl group, cyano group, nitro group, amino group, An alkylthio group, an alkylamino group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxyl group, or a sulfo group is represented. Two adjacent R ^1A , R ^2A , R ^3A , and R ^4A may be linked (condensed) with each other to form a ring. R ^5A or R ^6A and R ^7A or R ^8A may be linked to each other to form an aliphatic ring, but do not form an aromatic ring.

  Further, examples of the sensitizing dye that can be suitably used include compounds represented by the following general formula (iB).

In the formula (iB), X represents O or S. R ^1B , R ^2B , R ^3B , R ^4B , R ^5B , R ^6B , R ^7B , and R ^8B are each independently a hydrogen atom, an alkyl group, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amino group, An alkylthio group, an alkylamino group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxyl group, or a sulfo group is represented. Further, R ^1B , R ^2B , R ^3B , and R ^4B may be linked (condensed) with each other adjacent two to form a ring. R ^5B or R ^6B and R ^7B or R ^8B may be linked to each other to form an aliphatic ring, but do not form an aromatic ring.

  Examples of sensitizing dyes that can be used more suitably include sensitizing dyes represented by the following general formula (iC).

In the general formula (iC), R ^1C , R ^2C , R ^3C , R ^4C , R ^5C , R ^6C , R ^7C , and R ^8C are each independently a hydrogen atom, an alkyl group, a halogen atom, a hydroxyl group, cyano Represents a group, a nitro group, an amino group, an alkylthio group, an alkylamino group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxyl group, or a sulfo group.
R ^1C , R ^2C , R ^3C , and R ^4C may be formed by condensing two adjacent groups to form a 5- to 6-membered aliphatic ring or an aromatic ring. Heterocycles containing elements other than carbon atoms may be used, and the formed rings may be further combined to form a binuclear ring, for example, a condensed ring. Further, these ring structures are exemplified when R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ represent a monovalent substituent in the general formula (i). Each of the substituents may be further included. When the ring structure is a heterocyclic ring, examples of heteroatoms include N, O, and S. R ^5C or R ^6C and R ^7C or R ^8C may be linked to each other to form an aliphatic ring, but do not form an aromatic ring.

In addition, at least one of R ^1C , R ^2C , R ^3C , R ^4C , R ^5C , R ^6C , R ^7C , and R ^8C is preferably a halogen atom. Preferred substitution positions for the halogen atom include R ^1C , R ^2C , R ^3C , and R ^4C , with R ^2C being most preferred. The number of halogen atoms is preferably one or two, and more preferably one.

Furthermore, R ^2C is preferably a substituent other than hydrogen, and among them, an alkyl group, a halogen atom, an acyloxy group, and an alkoxycarbonyl group are preferable, and an alkyl group and a halogen atom are particularly preferable. Is highly sensitive.

In addition, either R ^7C or R ^8C is preferably a substituent other than hydrogen, and more preferably both are substituents other than hydrogen. Preferable substituents include an alkyl group, a halogen atom, a carboxyl group, and an alkoxycarbonyl group. Among them, an alkyl group and an alkoxycarbonyl group are preferable, and an alkyl group is most preferable.

When any of R ^1C , R ^2C , R ^3C , R ^4C , R ^5C , R ^6C , R ^7C , and R ^8C is an alkyl group, the alkyl group includes an alkyl group having 1 to 10 carbon atoms. Preferably, those having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group and t-butyl group are more preferable.
When any of R ^1C , R ^2C , R ^3C , R ^4C , R ^5C , R ^6C , R ^7C , and R ^8C is a halogen atom, the halogen atom includes a fluorine atom, chlorine atom, bromine atom, iodine An atom can be mentioned, A chlorine atom, a bromine atom, and an iodine atom are preferable.

When any of R ^1C , R ^2C , R ^3C , R ^4C , R ^5C , R ^6C , R ^7C , and R ^8C is an acyloxy group, the acyloxy group is an aliphatic acyloxy group having 2 to 10 carbon atoms. And an aliphatic acyloxy group having 2 to 5 carbon atoms is more preferable.
When any of R ^1C , R ^2C , R ^3C , R ^4C , R ^5C , R ^6C , R ^7C , and R ^8C is an alkoxycarbonyl group, the alkoxycarbonyl group includes a fatty acid having 2 to 10 carbon atoms A group alkoxycarbonyl group is preferable, and an alkoxycarbonyl group having 2 to 5 carbon atoms is more preferable.

  Specific examples of the specific sensitizing dye that can be suitably used in the present invention [Exemplary compounds (I-1) to (I-133)] are shown below, but the present invention is not limited thereto.

  Specific sensitizing dyes according to the present invention include, for example, Japanese Patent Application Laid-Open No. 2004-189695, “Tetrahedron” Vol. 49, p939 (1993), “Journal of Organic Chemistry” p893 (1945), and “Journal”. of Organic Chemistry "p4939 (1965) and the like.

The content of the specific sensitizing dye in the ink composition of the present invention is preferably about 0.05% by mass to 30% by mass, and preferably 0.1% by mass to 20% by mass with respect to the ink composition as a solid content. More preferably, it is more preferable that it is 0.2 mass%-10 mass%.
In addition, since this specific sensitizing dye hardly absorbs in the visible light region, it has an advantage that there is no concern of affecting the hue of the ink composition even if an amount capable of exhibiting the effect is added. .
When the content is described in relation to the aforementioned radical polymerization initiator, the mass ratio of specific polymerization initiator: specific sensitizing dye is 200: 1 to 1: 200, preferably 50: 1 to 1:50. Preferably, it is contained in an amount of 20: 1 to 1: 5.

[Other sensitizing dyes]
In the present invention, in addition to the specific sensitizing dye described above, a known sensitizing dye can be used in combination as long as the effects of the present invention are not impaired. The other sensitizing dye is 1: 5 to 100: 1, preferably 1: 1 to 100: 1, more preferably, in a mass ratio of the specific sensitizing dye to the other sensitizing dye with respect to the specific sensitizing dye. Can be added in an amount of 2: 1 to 100: 1.
Examples of known sensitizing dyes that can be used in combination include benzophenone, thioxanthone (particularly isopropylthioxanthone), anthraquinone, 3-acylcoumarin derivatives, terphenyl, styryl ketone, 3- (aroylmethylene) thiazoline, camphorquinone, and eosin. , Rhodamine, erythrosine and the like.
Further examples of sensitizing dyes that can be used in combination are as follows.

(1) Thioxanthone Thioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-dodecylthioxanthone, 2,4-di-ethylthioxanthone, 2,4-dimethylthioxanthone, 1-methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3 -(2-methoxyethoxycarbonyl) thioxanthone, 4-butoxycarbonylthioxanthone, 3-butoxycarbonyl-7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-ethoxycarbonyl-3-chlorothioxanthone, 1-ethoxycarbonyl- 3-ethoxythioxanthone, 1-ethoxycarbonyl-3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfurylthioxanthone, 3,4- Di- [2- (2-methoxyethoxy) ethoxycarbonyl] thioxanthone, 1-ethoxycarbonyl-3- (1-methyl-1-morpholinoethyl) thioxanthone, 2-methyl-6-dimethoxymethylthioxanthone, 2-methyl-6 -(1,1-dimethoxybenzyl) thioxanthone, 2-morpholinomethylthioxanthone, 2-methyl-6-morpholinomethylthioxanthone, n-allylthioxanthone-3,4-dicarboximide, n-octylthioxanthone-3,4-di Carboximide, N- (1,1,3,3-tetramethylbutyl) thioxanthone-3,4-dicarboximide, 1-phenoxythioxanthone, 6-ethoxycarbonyl-2-methoxythioxanthone, 6-ethoxycarbonyl-2- Methylthioxanthate , Thioxanthone-2-polyethylene glycol ester, 2-hydroxy-3- (3,4-dimethyl-9-oxo -9H- thioxanthone-2-yloxy) -N, N, N-trimethyl-1-propanaminium chloride;

(2) Benzophenone Benzophenone, 4-phenylbenzophenone, 4-methoxybenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-dimethylbenzophenone, 4,4′-dichlorobenzophenone, 4,4′-dimethylaminobenzophenone, 4 , 4'-diethylaminobenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4- (4-methylthiophenyl) benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, methyl-2-benzoylbenzoate 4- (2-hydroxyethylthio) benzophenone, 4- (4-tolylthio) benzophenone, 4-benzoyl-N, N, N-trimethylbenzenemethanaminium chloride, 2-hydroxy-3- (4-benzoylphenoxy) ) -N, N, N-trimethyl-1-propanaminium chloride monohydrate, 4- (13-acryloyl-1,4,7,10,13-pentaoxatridecyl) benzophenone, 4-benzoyl-N , N-dimethyl-N- [2- (1-oxo-2-propenyl) oxy] ethylbenzenemethanaminium chloride;

(3) 3-acylcoumarin 3-benzoylcoumarin, 3-benzoyl-7-methoxycoumarin, 3-benzoyl-5,7-di (propoxy) coumarin, 3-benzoyl-6,8-dichlorocoumarin, 3-benzoyl- 6-chlorocoumarin, 3,3′-carbonylbis [5,7-di (propoxy) coumarin], 3,3′-carbonylbis (7-methoxycoumarin), 3,3′-carbonylbis (7-diethylaminocoumarin) ), 3-isobutyroylcoumarin, 3-benzoyl-5,7-dimethoxycoumarin, 3-benzoyl-5,7-diethoxycoumarin, 3-benzoyl-5,7-dibutoxycoumarin, 3-benzoyl-5 7-di (methoxyethoxy) coumarin, 3-benzoyl-5,7-di (allyloxy) coumarin, 3-benzoyl-7- Dimethylaminocoumarin, 3-benzoyl-7-diethylaminocoumarin, 3-isobutyroyl-7-dimethylaminocoumarin, 5,7-dimethoxy-3- (1-naphthoyl) coumarin, 5,7-dimethoxy-3- (1-naphthoyl) ) Coumarin, 3-benzoylbenzo [f] coumarin, 7-diethylamino-3-thienoylcoumarin, 3- (4-cyanobenzoyl) -5,7-dimethoxycoumarin;

(4) 3- (Aroylmethylene) thiazoline 3-methyl-2-benzoylmethylene-β-naphthothiazoline, 3-methyl-2-benzoylmethylenebenzothiazoline, 3-ethyl-2-propionylmethylene-β-naphthothiazoline;

(5) Anthracene 9,10-dimethoxy-anthracene, 9,10-diethoxy-anthracene, 9,10-dimethoxy-2-ethyl-anthracene,

(6) Other carbonyl compounds Acetophenone, 3-methoxyacetophenone, 4-phenylacetophenone, benzyl, 2-acetylnaphthalene, 2-naphthaldehyde, 9,10-naphtholaquinone, 9-fluorenone, dibenzosuberone, xanthone, 2,5 -Bis (4-diethylaminobenzylidene) cyclopentanone, α- (para-dimethylaminobenzylidene) ketone, such as 2- (4-dimethylaminobenzylidene) indan-1-one or 3- (4-dimethylaminophenyl)- 1-Indan-5-ylpropenone, 3-phenylthiophthalimide, N-methyl-3,5-di (ethylthio) phthalimide.

<(C) Radical polymerizable compound>
The ink composition of the present invention contains a radical polymerizable compound (hereinafter simply referred to as “radical polymerizable compound”) different from the above-mentioned (A) surface segregation polymer.
The radical polymerizable compound is a compound having at least one ethylenically unsaturated bond capable of radical polymerization in the molecule, and any compound having a structure different from the above-described (A) surface segregation polymer. A thing with chemical forms, such as a monomer, an oligomer, and a polymer, is contained. Only one kind of radically polymerizable compound may be used, or two or more kinds thereof may be used in combination at an arbitrary ratio in order to improve desired properties. It is preferable to use two or more kinds in combination for controlling performance such as reactivity and physical properties.

  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, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, bis (4-acryloxypolyethoxyphenyl) propane, neopentyl glycol Diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, pentaerythritol triacrylate, pentaerythritol Tetraacrylate, dipentaery Acrylic acid derivatives such as lithol tetraacrylate, trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, N-methylol acrylamide, diacetone acrylamide, epoxy acrylate, methyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate , Lauryl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, 1,6-hexanediol dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylol Methacryl derivatives such as tan trimethacrylate, trimethylolpropane trimethacrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, and other derivatives of allyl compounds such as allyl glycidyl ether, diallyl phthalate, triallyl trimellitate More specifically, Yamashita Junzo, “Cross-linker Handbook”, (1981 Taiseisha); Kato Kiyomi, “UV / EB Curing Handbook (Raw Materials)” (1985, Polymer Publication) ); Rad-Tech Study Group, “Application and Market of UV / EB Curing Technology”, p. 79, (1989, CMC); Eiichiro Takiyama, “Polyester Resin Handbook”, (1988, Nikkan Kogyo Shimbun) Commercially available products described in the above, or radically polymerizable or crosslinkable monomers known in the industry, Ligomers and polymers can be used.

  Examples of the radical polymerizable compound include those disclosed in JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, JP-A-10-863, JP-A-9-134011, and the like. Photo-curable polymerizable compound materials used for the described photopolymerizable compositions are known, and these can also be applied to the ink composition of the present invention.

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

In the total solid content of the ink composition of the present invention, the content of the radical polymerizable compound is preferably 50% by mass to 90% by mass, more preferably 55% by mass to 90% by mass, and still more preferably. 60 mass% to 85 mass%. By setting it as the said range, a coating film with favorable curability and color reproducibility is obtained.
In order to further improve the flexibility of the coating film, the content of the monofunctional monomer in the total radical polymerizable compound is preferably 60% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and 80% by mass. % To 100% by mass is more preferable.

<(D) Radical polymerization initiator>
The ink composition of the present invention contains (D) a radical polymerization initiator.
In the present invention, it is preferable to contain a polymerization initiator selected from the group consisting of α-aminoketones and acylphosphine oxides described in detail below, and this polymerization initiator and other known polymerization initiators. An agent can be used in combination.

[Polymerization initiator selected from the group consisting of α-aminoketones and acylphosphine oxides]
Hereinafter, a polymerization initiator selected from the group consisting of α-aminoketones and acylphosphine oxides (hereinafter referred to as a specific polymerization initiator) will be described in detail.
The polymerization initiator suitably used in the present invention is a photopolymerization initiator selected from the group consisting of α-aminoketones and acylphosphine oxides.
The α-amino ketones that are specific polymerization initiators are compounds represented by the following general formula (1).

In General Formula (1), Ar is a phenyl group substituted with —SR ¹³ or —N (R ^7E ) (R ^8E ), where R ¹³ represents a hydrogen atom or an alkyl group. .
R ^1D and R ^2D are each independently an alkyl group having 1 to 8 carbon atoms. R ^1D and R ^2D may be bonded to each other to form an alkylene group having 2 to 9 carbon atoms.
R ^3D and R ^4D are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 2 to 4 carbon atoms substituted with 1 to 4 carbon atoms, or an alkenyl group having 3 to 5 carbon atoms. Represents a group. Here, R ^3D and R ^4D may be bonded to each other to form an alkylene group having 3 to 7 carbon atoms, and the alkylene group is —O— or —N (R ¹² ) — in the alkylene chain. Wherein R ¹² represents an alkyl group having 1 to 4 carbon atoms.
R ^7E and R ^8E each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 2 to 4 carbon atoms substituted with an alkoxy group having 1 to 4 carbon atoms, or an alkenyl group having 3 to 5 carbon atoms. Represents a group. Here, R ^7E and R ^8E may be bonded to each other to form an alkylene group having 3 to 7 carbon atoms, and the alkylene group is —O— or —N (R ¹² ) — in the alkylene chain. May be included. Here, R ¹² has the same meaning as described above.

  Examples of the compounds included in the α-amino ketones include 2-methyl-1-phenyl-2-morpholinopropan-1-one, 2-methyl-1- [4- (hexyl) phenyl] -2- And morpholinopropan-1-one, 2-ethyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, and the like. Further, Irgacure series manufactured by Ciba Geigy, for example, Irgacure 907, Irgacure 369, Irgacure 379, and the like are also available as commercial products, and these are compounds included in α-aminoketones, which are suitable for the present invention. Can be used for

  The compound included in the acylphosphine oxides is a compound represented by the following general formula (2) or general formula (3).

In the general formula (2), R ^5D and R ^6D each independently represent an aliphatic group, an aromatic group, an aliphatic oxy group, an aromatic oxy group, or a heterocyclic group, and R ^7D represents an aliphatic group. Represents a group, an aromatic group, or a heterocyclic group.

Examples of the aliphatic group represented by R ^5D , R ^6D, or R ^7D include 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. Among them, an alkyl group, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an aralkyl group, or a substituted aralkyl group is preferable, and an alkyl group and a substituted alkyl group are particularly preferable. The aliphatic group may be a cyclic aliphatic group or a chain aliphatic group. Moreover, the chain aliphatic group may have a branch.

  Examples of the alkyl group include linear, branched and cyclic alkyl groups, and the number of carbon atoms of the alkyl group is preferably 1 to 30, and more preferably 1 to 20. The preferred range of the number of carbon atoms in the alkyl part of the substituted alkyl group is the same as in the case of the alkyl group. Further, the alkyl group may be either a substituted alkyl group or an unsubstituted alkyl group. Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group, decyl group, dodecyl group, octadecyl group, cyclohexyl group, cyclopentyl group, neopentyl group, An isopropyl group, an isobutyl group, etc. are mentioned.

  Examples of the substituent of the substituted alkyl group include a carboxyl group, a sulfo group, a cyano group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom), a hydroxy group, and an alkoxycarbonyl group having 30 or less carbon atoms (for example, methoxycarbonyl). Group, ethoxycarbonyl group, benzyloxycarbonyl group), alkylsulfonylaminocarbonyl group having 30 or less carbon atoms, arylsulfonylaminocarbonyl group, alkylsulfonyl group, arylsulfonyl group, acylaminosulfonyl group having 30 or less carbon atoms, carbon number 30 The following alkoxy groups (for example, methoxy group, ethoxy group, benzyloxy group, phenoxyethoxy group, phenethyloxy group, etc.), alkylthio groups having 30 or less carbon atoms (for example, methylthio group, ethylthio group, methylthioethylthioethyl group, etc.) An aryloxy group having 30 or less carbon atoms (eg, phenoxy group, p-tolyloxy group, 1-naphthoxy group, 2-naphthoxy group, etc.), nitro group, alkyl group having 30 or less carbon atoms, alkoxycarbonyloxy group, aryloxy A carbonyloxy group,

Acyloxy group having 30 or less carbon atoms (for example, acetyloxy group, propionyloxy group, etc.), Acyl group having 30 or less carbon atoms (for example, acetyl group, propionyl group, benzoyl group, etc.), carbamoyl group (for example, carbamoyl group, N , N-dimethylcarbamoyl group, morpholinocarbonyl group, piperidinocarbonyl group, etc.), sulfamoyl group (for example, sulfamoyl group, N, N-dimethylsulfamoyl group, morpholinosulfonyl group, piperidinosulfonyl group, etc.), carbon An aryl group having a number of 30 or less (for example, phenyl group, 4-chlorophenyl group, 4-methylphenyl group, α-naphthyl group, etc.), substituted amino group (for example, amino group, alkylamino group, dialkylamino group, arylamino group) , Diarylamino group, acylamino group, etc.), substituted urea De group, a substituted phosphono group, and a heterocyclic group. Here, the carboxyl group, the sulfo group, the hydroxy group, and the phosphono group may be in a salt state. At that time, examples of the cation forming the salt include M ⁺ described later.

  Examples of the alkenyl group include linear, branched, and cyclic alkenyl groups. The number of carbon atoms of the alkenyl group is preferably 2 to 30, and more preferably 2 to 20. The alkenyl group may be a substituted alkenyl group having a substituent or an unsubstituted alkenyl group, and the preferred range of the number of carbon atoms in the alkenyl part of the substituted alkenyl group is the same as that of the alkenyl group. . Examples of the substituent of the substituted alkenyl group include the same substituents as those of the substituted alkyl group.

  Examples of the alkynyl group include linear, branched, and cyclic alkynyl groups, and the number of carbon atoms of the alkynyl group is preferably 2 to 30, and more preferably 2 to 20. The alkynyl group may be a substituted alkynyl group having a substituent or an unsubstituted alkynyl group, and the preferred range of the number of carbon atoms in the alkynyl part of the substituted alkynyl group is the same as in the case of the alkynyl group. . Examples of the substituent for the substituted alkynyl group include the same substituents as those for the substituted alkyl group.

  Examples of the aralkyl group include linear, branched, and cyclic aralkyl groups. The number of carbon atoms in the aralkyl group is preferably 7 to 35, and more preferably 7 to 25. The aralkyl group may be a substituted aralkyl group having a substituent or an unsubstituted aralkyl group, and the preferred range of the number of carbon atoms in the aralkyl part of the substituted aralkyl group is the same as in the case of the aralkyl group. . Examples of the substituent for the substituted aralkyl group include the same substituents as those for the substituted alkyl group.

Examples of the aromatic group represented by R ^5D , R ^6D or R ^7D include an aryl group and a substituted aryl group. As a carbon atom number of an aryl group, 6-30 are preferable and 6-20 are more preferable. The preferable range of the number of carbon atoms in the aryl part of the substituted aryl group is the same as that of the aryl group. Examples of the aryl group include a phenyl group, an α-naphthyl group, a β-naphthyl group, and the like. Examples of the substituent for the substituted aryl group include the same substituents as those for the substituted alkyl group.

The aliphatic oxy group represented by R ^5D or R ^6D is preferably an alkoxy group having 1 to 30 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a butoxy group, an octyloxy group, and a phenoxyethoxy group. . However, it is not limited to these.

The aromatic oxy group represented by R ^5D or R ^6D is preferably an aryloxy group having 6 to 30 carbon atoms, such as a phenoxy group, a methylphenyloxy group, a chlorophenyloxy group, a methoxyphenyloxy group, or an octyloxy group. A phenyloxy group etc. are mentioned. However, it is not limited to these.

The heterocyclic group represented by R ^5D , R ^6D or R ^7D is preferably a heterocyclic group containing an N, O or S atom, for example, a pyridyl group, a furyl group, a thienyl group, an imidazolyl group, a pyrrolyl group or the like. Is mentioned.

R ^8D and R ^10D in the general formula (3) each independently represent an alkyl group, an aryl group, or a heterocyclic group, and R ^9D represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, or Represents a heterocyclic group. The alkyl group, aryl group, heterocyclic group, alkoxy group, and aryloxy group represented by R ^8D , R ^9D, or R ^10D may have a substituent, and as the substituent, Examples thereof include the same substituents as in the general formula (2).

  The alkyl group, aryl group, heterocyclic group, alkoxy group, and aryloxy group in the general formula (3) have the same meaning as in the general formula (2).

  Examples of the acylphosphine oxides represented by the general formula (2) or the general formula (3) include, for example, Japanese Patent Publication No. 63-40799, Japanese Patent Publication No. 5-29234, Japanese Patent Application Laid-Open No. 10-95788, Examples thereof include compounds described in JP-A-10-29997.

  Specific examples of acylphosphine oxides include the following compounds [Exemplary compounds (P-1) to (P-26)], but the present invention is not limited to these. .

  Among the exemplified compounds, for example, (P-2) [2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide] is available under the trade name of Darocur TPO (manufactured by Ciba Specialty Chemicals), (P-19) [Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide] is available under the trade name Irgacure 819 (Ciba Specialty Chemicals).

  The content of the specific polymerization initiator in the ink composition of the present invention is preferably in the range of 0.1 to 30% by mass and in the range of 0.2 to 20% by mass in terms of solid content. More preferred.

[Other polymerization initiators]
The ink composition of the present invention may be used in combination with another photopolymerization initiator in addition to the specific polymerization initiator as a radical polymerization initiator.
As other photopolymerization initiators, known compounds can be used, but preferred compounds that can be used in the present invention include (A) aromatic ketones, (B) acylphosphine oxide compounds, and (C) aromatic oniums. Salt compound, (D) organic peroxide, (E) thio compound, (F) hexaarylbiimidazole compound, (G) ketoxime ester compound, (H) borate compound, (I) azinium compound, (J) metallocene Compounds, (K) active ester compounds, (L) compounds having a carbon halogen bond, and (M) alkylamine compounds.
In the present invention, other photopolymerization initiators may be used alone or in combination. From the viewpoint of the effect, it is preferable to use two or more other photopolymerization initiators in combination.

  As other photopolymerization initiators used in the present invention, specifically, for example, benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, benzyl, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, bis (2,4,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 1 , 2-octanedione, 1- (4- (phenylthio) -2,2- (O-benzoyloxime)) and the like. Further, other molecular cleavage initiators include 1-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropyl Phenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, and the like may be used in combination. Further, isophthalphenone, 4-benzoyl-4′-methyl-diphenyl sulfide, etc., which are hydrogen abstraction type photoinitiators, can be used in combination.

The content of the radical polymerization initiator in the ink composition of the present invention is preferably 0.01 parts by mass to 35 parts by mass with respect to 100 parts by mass of the total content of the above-described radical polymerizable compounds, and more preferably. It is 0.1 mass part-30 mass parts, More preferably, it is 0.5 mass part-30 mass parts.
In addition, content of the radical polymerization initiator described here means the total content of radical polymerization initiators including the specific polymerization initiator and other polymerization initiators that can be used in combination.

<(E) Colorant>
The ink composition of the present invention may contain (E) a colorant having various hues.
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 or ink-jet ink composition of the present invention 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.

[Pigment]
The pigment is not particularly limited, and all commercially available organic and inorganic pigments or pigments dispersed in an insoluble resin or the like as a dispersion medium, or the resin is grafted onto the pigment surface Can be used. Moreover, what dye | stained the resin particle with dye can be used.
Examples of these pigments include, for example, “Pigment Dictionary” (2000), edited by Seijiro Ito. Herbst, K.M. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Specific examples of organic pigments and inorganic pigments that can be used in the present invention include C.I. I. Pigment Yellow 1 (Fast Yellow G etc.), C.I. I. Pigment yellow 74, C.I. I. Monoazo pigments such as CI Pigment Yellow 120; I. Pigment yellow 155, C.I. I. Pigment Yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as C.I. Pigment Yellow 17; I. Non-benzidine type azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Condensed azo pigments such as CI Pigment Yellow 95 (Condensed Azo Yellow GR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (such as quinoline yellow lake); I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.); I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow, etc.).

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

  As a pigment exhibiting blue or cyan, C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Phthalocyanine pigments such as C.I. Pigment Blue 15 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).

  As a pigment exhibiting green, C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).

  As a pigment exhibiting an orange color, C.I. I. An isoindoline pigment such as C.I. Pigment Orange 66 (isoindoline orange); I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

  Examples of the black pigment include carbon black, titanium black, and aniline black.

Specific examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), Strontium titanate (SrTiO ₃ , so-called titanium strontium white) or the like can be used.

  Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so that it has a large hiding power and coloring power as a pigment. Excellent durability against other environments. Therefore, it is preferable to use titanium oxide as the white pigment. Of course, other white pigments (may be other than the listed white pigments) may be used as necessary.

For dispersing the pigment, for example, a dispersing device such as a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, or a wet jet mill is used. be able to.
It is also possible to add a dispersant when dispersing the pigment. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular weight copolymer, a modified polyacrylate, an aliphatic Examples thereof include polyvalent carboxylic acids, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate esters, and pigment derivatives. It is also preferable to use a commercially available polymer dispersant such as the Solsperse series from Noveon.
Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

  In the ink composition of the present invention, as a dispersion medium for various components such as a pigment, a solvent may be added, or a solvent-free solvent may be used, but the ink composition to which the ink composition of the present invention is applied is It is a radiation curable ink, and is preferably solvent-free because it is cured after the ink composition is applied onto the recording medium. This is because if the solvent remains in the cured ink image, the solvent resistance is deteriorated or a VOC (Volatile Organic Compound) problem of the remaining solvent occurs.

The average particle diameter of the pigment is preferably 0.02 to 0.9 μm, more preferably 0.05 to 0.8 μm, and more preferably 0.06 to 0.6 μm.
The selection of pigment, dispersant, dispersion medium, dispersion conditions, and filtration conditions are set so that the average particle diameter of the pigment particles is within the above-mentioned preferable range. By controlling the particle size, when the ink composition of the present invention is applied to inkjet recording, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

[dye]
The dye that can be used in the present invention is preferably oil-soluble. Specifically, it means that the solubility in water at 25 ° C. (the mass of the dye dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. Therefore, a so-called water-insoluble oil-soluble dye is preferably used.

The dye that can be used in the present invention preferably has an oil-solubilizing group introduced into the dye matrix in order to dissolve the necessary amount in the ink composition.
As the oil-solubilizing group, long chain, branched alkyl group, long chain, branched alkoxy group, long chain, branched alkylthio group, long chain, branched alkylsulfonyl group, long chain, branched acyloxy group, long chain, branched alkoxycarbonyl group, Long chain, branched acyl group, long chain, branched acylamino group long chain, branched alkylsulfonylamino group, long chain, branched alkylaminosulfonyl group and these long chains, aryl groups containing branched substituents, aryloxy groups, aryloxycarbonyl Group, arylcarbonyloxy group, arylaminocarbonyl group, arylaminosulfonyl group, arylsulfonylamino group and the like.
In addition, for water-soluble dyes having carboxylic acid and sulfonic acid, long chain, branched alcohol, amine, phenol, aniline derivatives are used as oil-solubilizing alkoxycarbonyl groups, aryloxycarbonyl groups, alkylaminosulfonyl groups, A dye may be obtained by conversion to an arylaminosulfonyl group.

The oil-soluble dye preferably has a melting point of 200 ° C. or lower, more preferably has a melting point of 150 ° C. or lower, and still more preferably has a melting point of 100 ° C. or lower. By using an oil-soluble dye having a low melting point, dye crystal precipitation in the ink composition is suppressed, and the storage stability of the photocured product is improved.
Further, it is desirable that the oxidation potential is noble (high) in order to improve fading, particularly resistance to oxidizing substances such as ozone and curing characteristics. For this reason, as the oil-soluble dye used in the present invention, those having an oxidation potential of 1.0 V (vs SCE) or more are preferably used. The oxidation potential is preferably higher, the oxidation potential is more preferably 1.1 V (vs SCE) or more, and particularly preferably 1.15 V (vs SCE) or more.

As the yellow dye, a compound having a structure represented by the general formula (Y-I) described in JP-A No. 2004-250483 is preferable.
Particularly preferred dyes are dyes represented by general formulas (Y-II) to (Y-IV) described in paragraph [0034] of JP-A No. 2004-250483. And the compounds described in paragraph numbers [0060] to [0071] of JP-A-250483. The oil-soluble dye represented by the general formula (Y-I) described in the publication may be used not only for yellow but also for inks of any color such as black ink and red ink.

The magenta dye is preferably a compound having a structure represented by the general formulas (3) and (4) described in JP-A No. 2002-114930. Specific examples include paragraphs of JP-A No. 2002-114930. Examples include the compounds described in [0054] to [0073].
Particularly preferred dyes are azo dyes represented by the general formulas (M-1) to (M-2) described in paragraph numbers [0084] to [0122] of JP-A No. 2002-121414, and specific examples Examples thereof include compounds described in paragraph numbers [0123] to [0132] of JP-A No. 2002-121414. The oil-soluble dyes represented by the general formulas (3), (4) and (M-1) to (M-2) described in the publication are used not only for magenta but also for any color ink such as black ink and red ink. May be.

Examples of the cyan dye include dyes represented by formulas (I) to (IV) described in JP-A No. 2001-181547, and paragraphs [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) described above are preferred, and specific examples include paragraph numbers [0052] to [0066] of JP-A No. 2001-181547. Examples thereof include the compounds described in paragraph Nos. [0079] to [0081] of Kai 2002-121414.
Particularly preferred dyes are phthalocyanine dyes represented by general formulas (CI) and (C-II) described in paragraphs [0133] to [0196] of JP-A No. 2002-121414, A phthalocyanine dye represented by formula (C-II) is preferred. Specific examples thereof include the compounds described in JP-A No. 2002-121414, paragraph numbers [0198] to [0201]. The oil-soluble dyes of the formulas (I) to (IV), (IV-1) to (IV-4), (CI), and (C-II) are not only cyan but also black ink or green ink. The ink may be used for any color ink.

-Oxidation potential-
The oxidation potential value (Eox) of the dye in the present invention can be easily measured by those skilled in the art. Regarding this method, for example Delahay, “New Instrumental Methods in Electrochemistry” (1954, published by Interscience Publishers); J. et al. "Electrochemical Methods" by Bard et al. (1980, published by John Wiley & Sons) and Akira Fujishima et al., "Electrochemical Measurement Method" (published by Gihodo Publishing Co., Ltd., 1984).
Specifically, the oxidation potential is measured by placing a test sample in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate in the range of 1 × 10 ⁻² to 1 × 10 ⁻⁶ mol / 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 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) The potential value is measured as a value relative to 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.

  These colorants are preferably added in an amount of 1% by mass to 30% by mass in terms of solid content in the ink composition, and more preferably 2% by mass to 25% by mass.

In the ink composition of the present invention, in addition to the above components, other components can be used in combination for the purpose of improving physical properties, as long as the effects of the present invention are not impaired.
Hereinafter, these optional components will be described below.

<Co-sensitizer>
The ink composition of the present invention can also contain 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 co-sensitizers include amines such as M.I. R. Sander et al., “Journal of Polymer Science”, Vol. 10, page 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, Japanese Patent Publication No. 59-138205. No. 60-84305, JP-A 62-18537, JP-A 64-33104, Research Disclosure 33825, and the like. Specific examples include triethanolamine. P-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

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

  Other examples of the co-sensitizer include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in JP-B-48-42965 (eg, tributyltin acetate), JP-B 55- No. 34414, a hydrogen donor described in JP-A-6-308727 (eg, trithiane), a phosphorus compound described in JP-A-6-250387 (eg diethylphosphite), JP-A-8-65779 Si-H and Ge-H compounds described in the above No.

<Ultraviolet absorber>
In the ink composition of the present invention, an ultraviolet absorber can be used from the viewpoint of improving the weather resistance of the obtained image and preventing discoloration.
Examples of the ultraviolet absorber are described in JP-A-58-185679, JP-A-61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194843, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492 and 56-21141 Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP The triazine compounds described in JP-A-8-501291, Research Disclosure No. Examples thereof include compounds described in No. 24239, compounds that emit ultraviolet light by absorbing ultraviolet rays typified by stilbene and benzoxazole compounds, so-called fluorescent brighteners, and the like.
The addition amount is appropriately selected according to the purpose, but generally it is preferably 0.5% by mass to 15% by mass in terms of solid content.

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

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

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

<Solvent>
In order to improve the adhesion to the recording medium, it is also effective to add a very small amount of an organic solvent to the ink composition of the present invention.
Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, and tert-butanol, and chlorine such as chloroform and methylene chloride. Solvents, aromatic solvents such as benzene and toluene, ester solvents such as ethyl acetate, butyl acetate and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, glycols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether And ether solvents.
In this case, it is effective to add the solvent within a range that does not cause the problem of solvent resistance and VOC, and the amount thereof is preferably 0.1% by mass to 5% by mass, more preferably 0.1% by mass with respect to the entire ink composition. % To 3% by mass.

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

<Surfactant>
A surfactant may be added to the ink composition of the present invention.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts.
An organic fluoro compound may be used in place of the surfactant.
The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compound include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). (Columns 8 to 17) and those described in JP-A Nos. 62-135826.

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

[Preferred physical properties of ink composition]
When the ink composition of the present invention is applied to ink jet recording, the viscosity is preferably at a temperature at the time of ejection (for example, 40 ° C. to 80 ° C., preferably 25 ° C. to 30 ° C.) in consideration of ejectability. 7 mPa · s to 30 mPa · s, more preferably 7 mPa · s to 20 mPa · s. For example, the viscosity of the ink composition of the present invention at room temperature (25 ° C. to 30 ° C.) is preferably 35 to 500 mPa · s, more preferably 35 mPa · s 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 preferably 20 mN / m to 30 mN / m, more preferably 23 mN / m to 28 mN / m. When recording on various recording media such as polyolefin, PET, coated paper, and non-coated paper, 20 mN / m or more is preferable from the viewpoint of bleeding and penetration, and the wettability is preferably 30 mN / m or less.

  The ink composition of the present invention is suitably used for ink jet recording. When applied to ink jet recording, the ink composition of the present invention is ejected onto a recording medium by an ink jet recording apparatus, and then the ejected ink composition is irradiated with radiation and cured to perform recording.

  In the printed matter obtained by this ink composition, the image portion is cured by irradiation with radiation such as ultraviolet rays, and the strength of the image portion is excellent. Therefore, in addition to the image formation by the ink composition, for example, the ink of a lithographic printing plate It can be used for various purposes such as formation of a receiving layer (image portion).

<Inkjet recording method and printed matter>
The ink jet recording method to which the ink composition of the present invention is preferably applied (the ink jet recording method of the present invention) will be described below.
The ink jet recording method of the present invention comprises a step of ejecting the above-described ink composition of the present invention onto a recording medium (support, recording material, etc.) by an ink jet recording apparatus, and actinic radiation to the ejected ink composition. And a step of curing the ink composition. An image is formed on the recording medium by the cured ink composition.

The recording medium applied to the ink jet recording method of the present invention is not particularly limited, and various non-absorbing resin materials used for ordinary non-coated paper, coated paper, and so-called soft packaging, or the like. A resin film formed into a film can be used, and examples of the various plastic films include PET film, OPS film, OPP film, ONy film, PVC film, PE film, and TAC film. In addition, examples of the plastic that can be used as a recording medium material include polycarbonate, acrylic resin, ABS, polyacetal, PVA, and rubbers. Metals and glasses can also be used as the recording medium.
Furthermore, examples of the recording material applicable to the present invention include a support for a lithographic printing plate.

Examples of the actinic radiation applied to the ink jet recording method of the present invention include α rays, γ rays, X rays, ultraviolet rays, visible rays, infrared rays, and electron beams. The peak wavelength of the actinic radiation is preferably 200 nm to 600 nm, more preferably 300 nm to 450 nm, and still more preferably 350 nm to 420 nm. The output of active radiation is preferably 2,000 mJ / cm ² or less, more ^preferably from ^{10mJ / cm 2 ~2,000mJ / cm 2} , more preferably, 20 mJ ^/ cm 2 to 1, It was 000mJ / cm ^2, particularly ^{preferably 50mJ / cm 2 ~800mJ / cm 2} .

Particularly, in the ink jet recording method of the present invention, radiation is emission wavelength peak is 350Nm～420nm, and maximum illuminance of the surface of the recording medium becomes 10mW ^/ cm ² ~2,000mW ^/ cm 2 UV Irradiation from a light emitting diode that generates The ink composition of the present invention can be cured with high sensitivity even with low exposure light such as light emitted from a light emitting diode.

  In the ink jet recording method of the present invention, the ink composition of the present invention described above is used, and the ink composition is cured by irradiating actinic radiation. Therefore, the ink composition has excellent scratch resistance and has a smooth surface. A suppressed image can be formed. In addition, although irradiation of actinic radiation can expose collectively after discharging all the colors, it is more preferable to expose for every color from a viewpoint of hardening acceleration.

Moreover, the printed matter of the present invention is an image in which an image is formed from the ink composition of the present invention by the above-described ink jet recording method (the ink jet recording method of the present invention).
Therefore, the printed matter has an image excellent in scratch resistance and having reduced surface stickiness.

Further, as described above, the ink composition of the present invention is suitably used for image formation of general printed matter, and also suitably in an embodiment in which processing is performed after an image is formed on a recording medium such as a support. Can be used.
Nowadays, printed materials such as decorative sheets subjected to molding are used in various applications. For example, the membrane switch surface sheet used for electrical appliances, etc., is a click feeling on the switch part (click part) after an image (image) is formed on a thin plastic sheet (PET, polycarbonate, polystyrene, etc. with a membrane pressure of about 100 μm). Embossing is applied for the purpose. In addition, there are many examples of embossing the printed material after forming the image in order to finish the printed material in a matte tone or to give a three-dimensional appearance in design.

  In addition, vending machines for beverage products such as drinking water, tea and juice are widely used, and dummy displays showing products to be sold are displayed on these vending machines. As these dummy exhibits, first, a flat support with a decorative print (formed image) was made on a transparent thermoplastic resin sheet, and then a half size of a full-size beverage product container. It is manufactured so as to appeal the product image strongly by making a deeply formed product (in some cases deep drawing of 25 mm or more) by deep drawing and giving illumination from the back.

As a processing method for producing such a deep-drawn molded article of a decorated thermoplastic resin sheet, vacuum forming, pressure forming, or vacuum / pressure forming is most preferable. In vacuum forming, in principle, a flat support is preheated to a temperature at which it can be thermally deformed in advance, and this is sucked into a mold by decompression and stretched while being pressed and cooled to the mold. Pressure is applied from the opposite side to the mold and cooled by pressure. In vacuum / pressure forming, the pressure reduction and pressurization are performed simultaneously.
As for the performance of the ink used for the printed matter subjected to these processes, the obtained image (printed matter) is not likely to crack or peel off, and has a high impact resistance, flexibility, and substrate adhesion of the cured film. Is required. On the other hand, since the ink composition of the present invention has a specific compound, the surface can be cured efficiently, so that it is resistant to impacts, and further, a bulky flexible film (a soft film with low viscoelasticity). ), It is possible to ensure the curability of the surface (a film having high viscoelasticity and no stickiness), and therefore, particularly good effects can be exhibited in applications where the above-described processing is performed after image formation.
Among the above, the use of the ink composition of the present invention is particularly preferably for vacuum forming.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the embodiments in these examples. The following examples relate to inks for each color of UV inkjet. Further, in the following description, unless otherwise specified, “parts” means “parts by mass”.

[Example 1]
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink composition.

(Cyan ink composition)
・ Phenoxyethyl acrylate 25.0 parts ・ N-vinylcaprolactam 32.0 parts ・ FA-512A 13.4 parts ・ Solsperse 32000 (Noveon's dispersant) 0.4 parts ・ Irgalite Blue GLVO 3.6 parts (Ciba Specialty) Chemicals pigments)
-Genorad 16 (stabilizer manufactured by Rahn) 0.05 part-Rapi-Cure DVE-3 (vinyl ether manufactured by ISP Europe)
8.0 parts Darocur TPO 8.5 parts (Ciba Specialty Chemicals photopolymerization initiator)
Irgacure 907 [specific polymerization initiator] 4.0 parts (photopolymerization initiator manufactured by Ciba Specialty Chemicals)
-Byk 307 (defoamer manufactured by BYK Chemie) 0.05 part-Surface segregation polymer (a-1) 1.0 part-Specific sensitizing dye (I-1) 4.0 part

[Example 2]
The following components were stirred with a high-speed water-cooled stirrer to obtain a magenta UV inkjet ink composition.

(Magenta ink composition)
・ Phenoxyethyl acrylate 25.0 parts ・ N-vinylcaprolactam 32.0 parts ・ FA-512A 13.4 parts ・ Solsperse 32000 (Noveon dispersant) 0.4 part ・ Cinquasia Magenta RT-355 D
(Ciba Specialty Chemicals Pigment) 3.6 parts Genorad 16 (Rahn Stabilizer) 0.05 parts Rapid-Cure DVE-3 8.0 parts (ISP Europe Vinyl Ether)
Darocur TPO 8.5 parts (Ciba Specialty Chemicals photopolymerization initiator)
・ Irgacure 907 [specific polymerization initiator] 4.0 parts (Ciba Specialty Chemicals photoinitiator)
-Byk 307 (antifoam manufactured by BYK Chemie) 0.05 part-Surface segregation polymer (a-2) 1.0 part-Specific sensitizing dye (I-2) 4.0 part

Example 3
The following components were stirred with a high-speed water-cooled stirrer to obtain a yellow UV inkjet ink composition.

(Yellow color ink composition)
・ Phenoxyethyl acrylate 25.0 parts ・ N-vinylcaprolactam 36.0 parts ・ FA-512A 13.4 parts ・ Solsperse 32000 (Noveon dispersant) 0.4 parts ・ Chromophthalal Yellow LA 3.6 parts (Ciba Specialty) Chemicals pigments)
-Genorad 16 (stabilizer manufactured by Rahn) 0.05 parts-Rapi-Cure DVE-3 4.0 parts (vinyl ether manufactured by ISP Europe)
Darocur TPO 8.5 parts (Ciba Specialty Chemicals photopolymerization initiator)
Irgacure 907 [specific polymerization initiator] 4.0 parts (photopolymerization initiator manufactured by Ciba Specialty Chemicals)
-Byk 307 (defoaming agent manufactured by BYK Chemie) 0.05 part-Surface segregation specific polymer (a-3) 1.0 part-Specific sensitizing dye (I-4) 4.0 parts

Example 4
The following components were stirred with a high-speed water-cooled stirrer to obtain a black UV inkjet ink composition.

(Black ink composition)
-Phenoxyethyl acrylate 25.0 parts-N-vinylcaprolactam 36.0 parts-FA-512A 13.4 parts-Solsperse 32000 (Noveon's dispersant) 0.4 parts-Microlith Black C-K 2.6 parts ( Ciba Specialty Chemicals pigment)
-Genorad 16 (stabilizer manufactured by Rahn) 0.05 part-Rapi-Cure DVE-3 5.0 parts (vinyl ether manufactured by ISP Europe)
Darocur TPO 8.5 parts (Ciba Specialty Chemicals photopolymerization initiator)
Irgacure 907 [specific polymerization initiator] 4.0 parts (photopolymerization initiator manufactured by Ciba Specialty Chemicals)
-Byk 307 (defoamer manufactured by BYK Chemie) 0.05 part-Specific polymer (a-13) 1.0 part-Specific sensitizing dye (I-14) 4.0 parts

Example 5
The following components were stirred with a high-speed water-cooled stirrer to obtain a white UV inkjet ink composition.

(White ink composition)
・ Phenoxyethyl acrylate 20.0 parts ・ N-vinylcaprolactam 32.0 parts ・ FA-512A 10.0 parts ・ Solsperse 32000 (Noveon's dispersant) 0.4 parts ・ MICROLITH WHITE RA 15.0 parts ( Ciba Specialty Chemicals pigment)
-Genorad 16 (stabilizer manufactured by Rahn) 0.05 part-Rapi-Cure DVE-3 5.0 parts (vinyl ether manufactured by ISP Europe)
Darocur TPO 8.5 parts (Ciba Specialty Chemicals photopolymerization initiator)
Irgacure 907 [specific polymerization initiator] 4.0 parts (photopolymerization initiator manufactured by Ciba Specialty Chemicals)
-Byk 307 (defoamer manufactured by BYK Chemie) 0.05 part-Surface segregation polymer (a-14) 1.0 part-Specific sensitizing dye (I-15) 4.0 part

[Examples 6 to 8]
The surface segregation polymer (a-14) and the specific sensitizing dye (I-15) in the white UV inkjet ink composition of Example 5 were replaced with the surface segregation polymer and the specific sensitizing dye described in Table 1 below, respectively. A white UV inkjet ink composition was prepared in the same manner as in Example 5 except that.

[Comparative Examples 1 to 3]
The surface segregation polymer (a-14) and / or the specific sensitizing dye (I-15) in the white UV inkjet ink composition of Example 5 is changed as shown in Table 1 below, or not added A white UV inkjet ink composition was prepared in the same manner as in Example 5 except that.

[Evaluation]
<Inkjet image recording>
First, the prepared ink composition was filtered with a filter having an absolute filtration accuracy of 2 μm.
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 ink jet head, respectively, and temperature control was performed so that the nozzle portions were always 70 ° C. ± 2 ° C. The piezo-type inkjet head was driven so that multi-size dots of 8 pl to 30 pl could be ejected with a resolution of 720 × 720 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

Using the ink jet recording apparatus, the filtered ink composition was ejected at an environmental temperature of 25 ° C., and the UV-LED was irradiated with ultraviolet rays using NCCU033 manufactured by Nichia. The LED outputs ultraviolet light having a wavelength of 365 nm from one chip. When a current of about 500 mA is applied, light of about 100 mW is emitted from the chip. A plurality of these are arranged at intervals of 7 mm to obtain a power of 0.3 W / cm ^{2 on} the surface of the recording medium. The exposure time after ink droplet ejection and the exposure time can be changed depending on the transport speed of the recording medium and the distance between the head and the LED in the transport direction. In this embodiment, the exposure is performed about 0.2 seconds after landing.
Depending on the setting of the transport speed of the distance and the recording medium with the UV-LED and the recording medium, it is possible to adjust the exposure energy on the recording medium between 0.01J ^/ cm ² ~15J ^/ cm 2 . Note that the irradiation time was set until the sticky feeling disappeared on the image surface after the ultraviolet irradiation. A soft vinyl chloride sheet was used as the recording medium.

  Under these conditions, the exposure sensitivity and ejection stability of the ink composition, and the blocking sensitivity, stretch ratio, scratch resistance, and adhesion to the recording medium of the image formed using the ink composition are as follows. evaluated.

(Measurement of exposure sensitivity)
The exposure energy amount (mJ / cm ² ) at which the sticky feeling disappears on the solid image surface after irradiation with ultraviolet rays obtained by applying the above inkjet recording method was defined as exposure sensitivity. The smaller the value, the higher the sensitivity.
Allowable range of the exposure sensitivity is at 750 mJ / cm ² or less, more preferably 350 mJ / cm ² or less.

(Evaluation of ejection stability)
The ejection stability at the head nozzle of the ink composition (after filtration) obtained as described above was evaluated as follows.
That is, the number of nozzle losses in continuous ejection for 60 minutes was measured with a commercially available inkjet recording apparatus having a piezoelectric inkjet nozzle under the following conditions.
-Condition-
-Number of channels: 318 / head-Drive frequency: 4.8 kHz / dot
・ Ink drops: 7 drops, 42 pl
・ Temperature: 45 ℃

In the experiment, a method of performing exposure (exposure amount: 1,000 mW / cm ² ) after discharging the ink composition onto the PET substrate was used, and the number of nozzle losses (number of nozzles clogged) at that time was counted. .

-Evaluation criteria-
○: The number of nozzle loss is 0 or more and less than 5 △: The number of nozzle loss is 5 or more and less than 10 ×: The number of nozzle loss is 10 or more

(Blocking sensitivity evaluation)
500 images of PET (size: the same size as the soft vinyl chloride sheet imaged both vertically and horizontally, weight: 2 g / sheet) are superimposed on the image obtained by applying the above-described inkjet recording method after ultraviolet irradiation. The sample was allowed to stand for one day, and the transfer to PET was visually evaluated. The case where there was no transfer was indicated as ◯, the case where there was transfer as x, and the amount of exposure energy (mJ / cm ² ) required until there was no transfer was defined as the blocking sensitivity.
The allowable range of blocking sensitivity is 12,000 mJ / cm ² or less, more preferably 6,000 mJ / cm ² or less.

(Abrasion resistance evaluation)
A sample on which a solid image was printed on a soft vinyl chloride sheet at a resolution of 720 × 720 dpi was rubbed with an eraser (K-50 Plastic Eraser Keep from Hoshiya), and the transfer to the eraser was evaluated. The evaluation criteria are as follows.
-Evaluation criteria-
○: No transfer ×: Transfer

(Elongation rate evaluation)
The exposure sensitivity is evaluated except that the integrated exposure amount is 12,000 mJ / cm ² , the illuminance is 2140 mW / cm ² , and the support is made of Fasson PE (polyethylene film manufactured by Fasson: film thickness: 100 μm) instead of the soft vinyl chloride sheet. Similarly, a cured film was prepared. The obtained cured film is cut into a shaft length of 5 cm and a width of 2.5 cm, and stretched at a speed of 30 cm / min using a tensile tester (manufactured by Shimadzu Corporation, Autograph AGS-J), and the cured film is broken. The elongation was measured. The state of elongation from the initial length to twice the length was defined as 100% elongation.
The allowable range of the stretching ratio is 200% or more, more preferably 300% or more.

(Evaluation of adhesion)
Evaluation was performed by a cross hatch test using a sample in which a solid image was printed at a resolution of 720 × 720 dpi on an untreated polypropylene substrate. This test is evaluated on a scale of 0 to 5, with 0 being the best and 1 being a level with no practical problem.
-Evaluation criteria-
○: 0 range Δ: 1 range ×: 2-5 range

  Table 1 below shows the surface segregation polymers and specific sensitizing dyes in the ink compositions of Examples and Comparative Examples, and the evaluation results of the ink compositions.

  As is apparent from Table 1, the ink compositions of the examples have high exposure sensitivity and are excellent in ejection stability when applied to an ink jet recording apparatus. It can also be seen that the images obtained by curing the ink compositions of the examples have high blocking sensitivity, and are excellent in scratch resistance, stretchability, and adhesion to the recording medium.

Claims (6)

(A) a partial structure selected from the group consisting of a fluorine-substituted hydrocarbon group, a siloxane skeleton, and a long-chain alkyl group, and a polymer having a radically polymerizable group in the side chain;
(B) a sensitizing dye represented by the following general formula (i);
(C) a radically polymerizable compound different from the polymer of (A),
(D) a radical polymerization initiator;
An ink-jet ink composition comprising:

(In general formula (i), X represents O, S, or NR, R represents a hydrogen atom, an alkyl group, or an acyl group. N represents 0 or 1. R ^{1 to} R ^8. Each independently represents a hydrogen atom or a monovalent substituent, and R ¹ , R ² , R ³ , and R ⁴ may be bonded to each other to form a ring. R ⁵ or R ⁶ and R ⁷ or R ⁸ may be linked to each other to form an aliphatic ring, but they do not form an aromatic ring.   The ink composition for inkjet according to claim 1, further comprising (E) a colorant.   The inkjet ink composition according to claim 1 or 2, wherein the polymer (A) is a polymer whose main chain structure is synthesized by radical chain polymerization.   The inkjet ink composition according to claim 1 or 2, wherein the polymer (A) is a polymer containing a urethane structure or a urea structure as a repeating unit in the main chain structure. (1) A step of discharging the ink composition for inkjet according to any one of claims 1 to 4 onto a recording medium; and
(2) a step of irradiating the ejected ink composition for inkjet with actinic radiation to cure the ink composition;
An inkjet recording method comprising:   A printed matter recorded by the ink jet recording method according to claim 5.