JP5334477B2 - Photocurable composition, ink composition, and ink jet recording method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a photocurable composition having high sensitivity and capable of forming a cured film having high adhesion to a solid surface; an ink composition including the photocurable composition, having high curing sensitivity, excellent in color reproducibility, capable of forming an image having high adhesion to a recording medium, and suitable for inkjet recording; and an inkjet recording method using the ink composition. <P>SOLUTION: The photocurable composition includes (i) a sensitizing dye represented by general formula (I), (ii) a photopolymerization initiator represented by general formula (II), and (iii) a polymerizable compound having an ethylenically unsaturated bond. In the general formula (I), X represents O, S or NR, R represents H, alkyl or acyl; n represents 0 or 1; and R<SP>1</SP>-R<SP>8</SP>represent H or a monovalent substituent. In the general formula (II), A represents a divalent aromatic condensed ring group; Ar<SP>1</SP>represents a heterocyclic group or the like; and R<SP>21</SP>-R<SP>24</SP>represent alkyl, aryl, alkenyl or the like. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a photocurable composition that is cured with high sensitivity upon irradiation with actinic rays, an ink composition that is suitably used for inkjet recording using the composition, and an inkjet recording method. Specifically, a photocurable composition that cures with high sensitivity to irradiation with actinic radiation, and by containing the photocurable composition, it cures with high sensitivity and the cured product has sufficient flexibility even after ink curing. The present invention relates to an ink composition suitable for inkjet recording and an inkjet 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. The electrophotographic system requires a process of forming an electrostatic latent image on a photosensitive drum by charging and exposure, and there is a problem that the system becomes complicated and consequently the manufacturing cost becomes high. In addition, although the thermal transfer system is inexpensive, there are problems such as high running costs and waste materials due to the use of ink ribbons.
On the other hand, the ink jet method is an inexpensive device and ejects ink only to a required image portion to form an image directly on a recording medium. Therefore, the ink can be used efficiently and the running cost is low. Furthermore, there is little noise and it is excellent as an image recording method.

  Ink compositions that can be cured by irradiation with actinic radiation such as ultraviolet rays (radiation curable ink compositions), such as ink compositions for ink jet recording, can be cured with high sensitivity and form high-quality images. It has been demanded. By achieving high sensitivity, high curability is imparted by irradiation with actinic radiation, so that sufficient curing is achieved in addition to reducing power consumption and extending life by reducing the load on the actinic radiation generator. As a result, there are various advantages such as suppression of volatilization of uncured low molecular weight substances and reduction in the strength of the formed image.

  The curable inkjet method using ultraviolet light has been attracting attention in recent years because it has a relatively low odor and can record on a recording medium having no quick drying and no ink absorption. In particular, benzyl, benzoin, benzoin ethyl ether, Michler's ketone, anthraquinone, acridine, phenazine, benzophenone, 2-ethylanthraquinone, and the like have been generally used as photopolymerization initiators (see, for example, Non-Patent Document 1). However, when these photopolymerization initiators are used, it takes a long time for image exposure in image formation because the photopolymerizable composition has low curing sensitivity. For this reason, in the case of a fine image, if there is a slight vibration in the operation, an image with good image quality cannot be reproduced, and further, the amount of energy emitted from the light source of the exposure must be increased. It was necessary to consider radiation. In addition, ink used in the ink jet recording system requires various characteristics such as no change in physical properties or precipitation due to storage (solution stability), no clogging of the nozzle (ejection stability), etc. It is.

Generally, the use of various polymerization initiation systems has been disclosed as a method for increasing the sensitivity to radiation in a radiation-curable polymerizable compound (Non-patent Document 1, Patent Document 1, Patent Document 2, and Patent Document 3). ). However, there is no example in which an ink for ink jet recording employs a polymerization initiating system satisfying sufficient sensitivity for scanning exposure, storage stability, and ejection stability.
For this reason, ink that can be cured with high sensitivity to low-output radiation, can form high-quality images, and has good storage stability and ejection stability, and is suitably used for inkjet recording. Compositions are anxious.
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

The objective of this invention is providing the photocurable composition which can form the cured film which has high sensitivity with respect to irradiation of actinic radiation, and has high adhesiveness with respect to the solid surface.
Another object of the present invention is that it has high sensitivity to irradiation with actinic radiation, has excellent color reproducibility, and can form an image having high adhesion to a recording medium, and is suitable for inkjet recording. An ink composition and an ink jet recording method using the ink composition are provided.

In order to solve the above-mentioned problems, the present inventors have made extensive studies, and as a result, a specific sensitizing dye has a high sensitizing effect with respect to a specific initiator, and an ink composition using them as an initiator system is The present invention was completed by finding that it can be cured with high sensitivity and can form a flexible image.
That is, the photocurable composition of the present invention, a sensitizing dye represented by (i) the following general formula (I-C), a photopolymerization initiator represented by (ii) the following general formulas (II), ( and iii) a polymerizable compound having an ethylenically unsaturated bond.

(In the general formula ^{(I-C), R 1C} , R 2C, R 3C, R 4C, R 5C, R 6C, each independently ^{R 7C} and ^{R 8C,} represent a hydrogen atom, an alkyl group, or a halogen atom. )

In the formula (II), A represents a divalent aromatic fused ring group having 4 to 16 carbon atoms, and may be an aromatic heterofused ring group. Ar ¹ represents a group represented by the following (II-2).
R ²¹ and R ²² each independently represents an alkyl group, an aryl group, or an alkenyl group, and R ²¹ and R ²² are bonded to each other to form an alkylene group having 2 to 8 carbon atoms and 3 to 9 carbon atoms. May be formed, or an azaalkylene group having 3 to 9 carbon atoms. R ²³ and R ²⁴ each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, or COR ^10, which are bonded to each other to form an alkylene group having 2 to 6 carbon atoms, or 2 to 2 carbon atoms. A oxaalkylene group having 6 carbon atoms, a thiaalkylene group having 2 to 6 carbon atoms, or an azaalkylene group having 2 to 6 carbon atoms may be formed. Here, R ¹⁰ represents an alkyl group, an aryl group, an alkenyl group, an alkoxy group, or an aryloxy group.

In general formula (II-2), R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ and R ²⁹ are each independently a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an acyl group, an alkoxy group, an aryloxy group, An acyloxy group, an alkoxycarbonyloxy group, an alkylthio group, an arylthio group, an alkylamino group, a dialkylamino group, an arylamino group, a diarylamino group, an alkylarylamino group, or a halogen atom. R ^{25 to} R ²⁹ may integrally form an aromatic ring.

In addition, the ink composition of the present invention includes the photocurable composition of the present invention.
When forming a colored image with the ink composition of the present invention, it is preferable that the ink composition further contains a colorant. In addition, the ink composition of the present invention can be cured with high sensitivity by radiation irradiation, and therefore is suitable for inkjet recording.

The ink jet recording method of the present invention comprises: (a) a step of ejecting the ink composition of the present invention onto a recording medium; and (b) irradiating the ejected ink composition with actinic radiation to form an ink composition. And a step of curing.
Irradiation with actinic radiation at this time, the emission peak wavelength is in the range of 340Nm～370nm, and light emission which generates ultraviolet maximum illuminance of the surface of the recording medium becomes 10mW ^/ cm ² ~2,000mW ^/ cm 2 It is preferable that the ultraviolet ray is irradiated by the diode.

As an effect | action of this invention, it estimates as follows.
In the present invention, the photopolymerization initiator represented by the general formula (II) and the sensitization represented by the general formula (IC) which is a preferred embodiment of the specific sensitizing dye represented by the general formula (I). It adopts the initiating system used in combination with dyes, the specific sensitizing dye, triplet excitation energy is high, causing efficient triplet energy transfer to a specific polymerization initiator represented by the general formula (II) Therefore, it is considered that the specific polymerization initiator can be cured with high sensitivity in combination with the high radical generation efficiency of the specific polymerization initiator and the characteristic that the generated radical species are not easily inhibited by oxygen polymerization. In addition, the specific sensitizing dye has higher solubility and lower crystallinity than a commonly used thioxanthone compound, and thus has excellent stability as a solution of an ink composition, and an ink composition containing the same When the product is used for inkjet recording, it is considered that excellent ejection stability can be obtained.

ADVANTAGE OF THE INVENTION According to this invention, the photocurable composition which can form the cured film which has high sensitivity with respect to irradiation of actinic radiation, and has high adhesiveness with respect to a solid surface can be provided.
In addition, according to the present invention, an ink composition capable of forming an image having high sensitivity to irradiation with actinic radiation, excellent color reproducibility, and having high adhesion to a recording medium, and An ink jet recording method using the ink composition can be provided.

[Photocurable composition]
First, the photocurable composition of the present invention will be described in detail.
The photocurable composition of the present invention comprises (i) the following general formula (IC), which is a preferred embodiment of the sensitizing dye represented by the following general formula (I) (hereinafter referred to as a specific sensitizing dye as appropriate). ), A photopolymerization initiator represented by the following general formula (II) (hereinafter referred to as a specific polymerization initiator as appropriate), and (iii) a polymerization having an ethylenically unsaturated bond. A chemical compound.
The ink composition of the present invention can be suitably used for inkjet recording.
Hereinafter, components essential to the ink composition of the present invention will be sequentially described.

<(I) Sensitizing dye represented by formula (I)>
The curable composition of the present invention contains a sensitizing dye in order to promote decomposition of the polymerization initiator by irradiation with actinic rays. As the sensitizing dye, the specific sensitizing dye described in detail below is an essential component. contains.
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 photocurable composition of the present invention is a sensitizing dye represented by the following general formula (I-C), which is a preferred embodiment of the sensitizing dye (specific sensitizing dye) represented by the following general formula (I). It is necessary to contain.

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, and 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, examples of the monovalent substituent include a halogen atom, aliphatic group, aromatic Group, heterocyclic group, cyano group, hydroxy group, nitro group, amino group, alkylamino group, alkoxy group, aryloxy group, amide group, arylamino group, ureido group, sulfamoylamino group, alkylthio group, arylthio Group, alkoxycarbonylamino group, sulfonamido group, carbamoyl group, sulfamoyl group, sulfonyl group, alkoxycarbonyl group, heterocyclic oxy group, azo group, acyloxy group, carbamoyloxy group, silyloxy group, aryloxycarbonyl group, aryloxycarbonyl Amino group, imide group, heterocyclic thio group, sulfinyl group, phosphoryl group, acyl , A carboxyl group or a sulfo group. 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, Ten 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 linked 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. Further, 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 number of ring members of the aliphatic ring is preferably a 3- to 6-membered ring, more preferably a 5-membered ring or a 6-membered ring.

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

In the 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, alkylthio group Represents an alkylamino group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxyl group or a sulfo group. 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.

  Examples of sensitizing dyes that can be used more suitably include sensitizing dyes 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, alkyl group, halogen atom, hydroxyl group, cyano group, nitro group, amino group, alkylthio group Represents an alkylamino group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acyl group, a carboxyl group or a sulfo group. 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 ^combine with 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 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, alkyl group, halogen atom, hydroxyl group, cyano group Nitro group, amino group, alkylthio group, alkylamino group, alkoxy group, alkoxycarbonyl group, acyloxy group, acyl group, carboxyl group or 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 aromatic ring, and these rings are 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 substituent 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 ^combine with 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.

Further, 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.

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.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and 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 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 including the sensitizing dye represented by the general formula (IC) that can be suitably used in the present invention [Exemplary compounds (I-1) to (I-133)] are shown below. Although shown, this invention is not limited to these.

  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 photocurable 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 solid content with respect to the photocurable composition. It is more preferable that it is mass%, and it is more preferable that it is 0.2 mass%-10 mass%.
In addition, since this specific sensitizing dye has almost no absorption in the visible light region, it has an advantage that there is no concern of affecting the hue of the photocurable composition even when an amount capable of producing the effect is added. It is.
When the content is described in relation to the specific polymerization initiator described later, 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, in particular isopropylthioxanthone, anthraquinone and 3-acylcoumarin derivatives, terphenyl, styryl ketone and 3- (aroylmethylene) thiazoline, camphorquinone, eosin, Examples include rhodamine and erythrosine.

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.

<Polymerization initiator>
The photocurable composition of the present invention contains a polymerization initiator.
The present invention is characterized by containing the specific polymerization initiator described in detail below, but a known polymerization initiator can also be used in combination. As the polymerization initiator in the present invention, a radical polymerization initiator is preferably used.

[(Ii) Photopolymerization initiator represented by formula (II)]
Hereinafter, the specific polymerization initiator which is a characteristic component of the present invention will be described in detail.
The polymerization initiator suitably used in the present invention is a compound represented by the following general formula (II).

In the general formula (II), R ²¹ and R ²² each independently represents an alkyl group, an aryl group, or an alkenyl group, and R ²¹ and R ²² are bonded to each other to form an alkylene having 2 to 8 carbon atoms. A oxaalkylene group having 3 to 9 carbon atoms or an azaalkylene group having 3 to 9 carbon atoms may be formed.
R ²¹ is an alkyl group, an aryl group, or an alkenyl group. Specifically, it is a linear, branched, or cyclic alkyl group having 1 to 18 carbon atoms, or an alkenyl group or an aryl group having 4 to 18 carbon atoms. is there.

Examples of the alkyl group in the substituent R ²¹ in the general formula (II) include linear, branched, monocyclic or condensed polycyclic alkyl groups having 1 to 18 carbon atoms. Specific examples include methyl Group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, octadecyl group, isopropyl group, isobutyl group, isopentyl group, sec-butyl group, tert -Butyl group, sec-pentyl group, tert-pentyl group, tert-octyl group, neopentyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group, 4-decylcyclohexyl group, etc. However, it is not limited to these.

Examples of the aryl group in the substituent R ²¹ in the general formula (II) include a monocyclic or condensed polycyclic aryl group having 4 to 18 carbon atoms which may include a hetero atom, and specific examples thereof include a phenyl group, 1-naphthyl group, 2-naphthyl group, 9-anthryl group, 9-phenanthryl group, 1-pyrenyl group, 5-naphthacenyl group, 1-indenyl group, 2-azurenyl group, 1-acenaphthyl group, 2-furanyl group, 2 -Pyrrolyl group, 9-fluorenyl group, 2-furyl group, 2-thienyl group, 2-indolyl group, 3-indolyl group, 6-indolyl group, 2-benzofuryl group, 2-benzothienyl group, 4-quinolinyl group, 4-isoquinolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-acridinyl group, 3-phenothiazinyl group, 2-phenoxa Although a thiynyl group, 3-phenoxazinyl group, 3-thianthenyl group etc. can be mentioned, it is not limited to these.

As the linear, branched or cyclic alkenyl group having 1 to 18 carbon atoms in the substituent R ²¹ in the general formula (II), linear, branched, monocyclic or condensed having 1 to 18 carbon atoms And a polycyclic alkenyl group, which may have a plurality of carbon-carbon double bonds in the structure. Specific examples thereof include a vinyl group, a 1-propenyl group, a 2-propenyl group, and 2-butenyl. Group, 3-butenyl group, isopropenyl group, isobutenyl group, 1-pentenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4 -Hexenyl group, 5-hexenyl group, cyclopentenyl group, cyclohexenyl group, 1,3-butadienyl group, cyclohexadienyl group, cyclopentadienyl group, etc. However, it is not limited to these.

Of the above substituents, R ²¹ is preferably an alkyl group or an alkenyl group in terms of the difficulty of synthesis and sensitivity as a radical generator, and specifically includes a methyl group, an ethyl group, a benzyl group, A p-methylbenzyl group or a 2-propenyl group is particularly preferable.

The substituent R ²² in the general formula (II) has the same meaning as R ²¹ , but these are bonded to each other to form an alkylene group having 2 to 8 carbon atoms or an oxaalkylene having 3 to 9 carbon atoms. Group or an azaalkylene group may be formed.
As the alkylene group in the alkylene group having 2 to 8 carbon atoms formed by combining the substituents R ²² and R ²¹ in the general formula (II), R ²² is R ²¹ , and those bonded Examples of forming a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, and the like in combination with the carbon atoms present are not limited thereto. .

As the oxa- or azaalkylene group in the case of an oxaalkylene group or an azaalkylene group having 3 to 9 carbon atoms formed by combining the substituents R ²² and R ²¹ in the general formula (II), Examples include, but are not limited to, an aspect in which R ²² forms a tetrahydrofuran ring, a pyrrolidine ring, a piperidine ring, and the like together with R ²¹ and the carbon atom to which they are bonded.

R ²³ and R ²⁴ each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, or COR ^10, which are bonded to each other to form an alkylene group having 2 to 6 carbon atoms, or 2 to 2 carbon atoms. A oxaalkylene group having 6 carbon atoms, a thiaalkylene group having 2 to 6 carbon atoms, or an azaalkylene group having 2 to 6 carbon atoms may be formed. Here, R ¹⁰ represents an alkyl group, an aryl group, an alkenyl group, an alkoxy group, or an aryloxy group.

Here, when R ²³ and R ²⁴ represent an alkyl group or an aryl group, the alkyl group or aryl group has the same meaning as the alkyl group or aryl group in the description of R ²¹ .
The alkenyl group in the case where the substituents R ²³ and R ²⁴ in the general formula (II) represent an alkenyl group is a linear, branched or cyclic alkenyl group having 1 to 18 carbon atoms, Examples of the 18 linear or branched alkenyl groups include linear, branched, monocyclic or condensed polycyclic alkenyl groups having 1 to 18 carbon atoms, which have a plurality of carbon-carbon dicarbon groups in the structure. It may have a heavy bond, and specific examples include vinyl group, 1-propenyl group, 2-propenyl group, 2-butenyl group, 3-butenyl group, isopropenyl group, isobutenyl group, 1-pentenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, Ropenteniru group, cyclohexenyl group, 1,3-butadienyl group, cyclohexadienyl group, there may be mentioned the cyclopentadienyl group, but is not limited thereto.

Here, the substituent R ¹⁰ represents an alkyl group, an aryl group, an alkenyl group, an alkoxy group, or an aryloxy group, and the alkyl group, aryl group, and alkenyl group herein have the same meaning as in R ²¹ . .
Examples of the alkoxy group when R ¹⁰ represents an alkoxy group include linear, branched, monocyclic or condensed polycyclic alkoxy groups having 1 to 18 carbon atoms. Specific examples include methoxy group, ethoxy group Group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, dodecyloxy group, octadecyloxy group, isopropoxy group, isobutoxy group, isopentyloxy group, sec-butoxy group, tert-butoxy group, sec-pentyloxy group, tert-pentyloxy group, tert-octyloxy group, neopentyloxy group, cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group , Adamantyloxy group, Bornyloxy group, Boroniruokishi group, 4-decyl cyclohexyl group, 2-tetrahydrofuranyl group, and the like can be mentioned 2-tetrahydropyranyloxy group, but is not limited thereto.

When R ¹⁰ represents an aryloxy group, the aryloxy group includes a monocyclic or condensed polycyclic aryloxy group having 4 to 18 carbon atoms which may contain a hetero atom, and specific examples include a phenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, 9-anthryloxy group, 9-phenanthryloxy group, 1-pyrenyloxy group, 5-naphthacenyloxy group, 1-indenyloxy group, 2-azurenyloxy group, 1-acenaphthyloxy group, 9-fluorenyloxy group, 2-furanyloxy group, 2-thienyloxy group, 2-indolyloxy group, 3-indolyloxy group, 2-benzofuryloxy group, 2-benzo Thienyloxy, 2-carbazolyloxy, 3-carbazolyloxy, 4-carbazolyloxy, 9-acridinyloxy And the like can be mentioned groups, but is not limited thereto.

As the alkylene group in the case where the substituents R ²³ and R ²⁴ in the general formula (II) are bonded to form an alkylene having 2 to 6 carbon atoms, R ²³ is R ²⁴ , and they are bonded An embodiment in which a propyleneimine ring, a pyrrolidine ring, a piperidine ring, a pipecoline ring, or the like is formed in cooperation with the nitrogen atom can be exemplified, but is not limited thereto.
The oxaalkylene, thiaalkylene or aza in the case where the substituents R ²³ and R ²⁴ in the general formula (II) are bonded to each other to form an oxaalkylene, thiaalkylene or azaalkylene group having 2 to 6 carbon atoms Examples of the alkylene group include an embodiment in which R ²³ is combined with R ²⁴ and the nitrogen atom to which they are bonded to form a morpholine ring, thiomorpholine ring, thiazolidine ring, piperazine ring, or homopiperazine ring. However, it is not limited to these.

Among the above substituents, as the substituents R ²³ and R ²⁴ , an alkyl group, an alkenyl group, and substituents R ²³ and R ²⁴ are bonded to each other from the viewpoint of difficulty of synthesis and sensitivity as a radical generator. And preferably an alkylene group having 2 to 6 carbon atoms, an oxaalkylene group, a thiaalkylene group or an azaalkylene group having 2 to 6 carbon atoms, specifically, a methyl group, an ethyl group, or a morpholino group. A thiomorpholino group or a piperazino group is particularly preferred.

The monovalent substituent represented by R ^{21 to} R ²⁴ described above, or the divalent group formed by bonding R ²¹ and R ²² , R ²³ and R ²⁴ to each other further has a substituent. The substituents that can be introduced into these groups include alkyl groups, aryl groups, alkenyl groups, acyl groups, alkoxy groups, aryloxy groups, acyloxy groups, alkoxycarbonyloxy groups, alkylthio groups, arylthio groups, alkyl groups. Examples include an amino group, a dialkylamino group, an arylamino group, a diarylamino group, an alkylarylamino group, and a halogen atom.

In the formula (II), A represents a divalent aromatic fused ring group having 4 to 16 carbon atoms, and may be an aromatic heterofused ring group.
Here, the aromatic condensed ring group refers to a group derived from a product in which two or more rings are condensed and at least one ring is an aromatic ring. In particular, the aromatic condensed ring is preferably bonded so as to be conjugated with at least one of the two carbonyl groups in the general formula (II).
Here, the aromatic fused ring group may contain a hetero atom, but there is no particular limitation on the type of hetero atom, the number of hetero atoms, and the substitution position of the hetero atoms.
From the viewpoint of effects, the heteroatom is preferably a nitrogen atom, an oxygen atom, or a sulfur atom, and the number of heteroatoms contained is preferably 0 to 4.
In the case of containing a hetero atom, the substitution position of the hetero atom in the divalent aromatic fused ring group is not particularly limited, but at least one of the aromatic ring contained in A and the two carbonyl groups of the general formula (II) It is preferable that they are bonded so as not to block the conjugation.

  More specifically, the divalent aromatic fused ring group represented by A is represented by the following general formula (II-3), general formula (II-4), general formula (II-5), or general formula (II). Those represented by II-6) are preferred.

In general formula (II-3), Y represents —O—, —S—,>S═O,> SO ₂ , —N (R ¹¹ ) —, —CO—, —CH ₂ —, —CH ₂ CH _2. —, —CH═CH—, an alkylidene group having 2 to 6 carbon atoms, or a single bond, Z represents —O—, —S—,>S═O,> SO ₂ , —N (R ¹¹ ) —. _{, -CO -, - CH 2 -} , - CH 2 CH 2 -, - CH = CH-, represents an alkylidene group or a single bond having 2 to 6 carbon atoms.

In General Formula (II-4), U represents —O—, —S—, or —N (R ¹¹ ) —, wherein R ¹¹ represents an alkyl group, an aryl group, an alkenyl group, an alkoxy group, An aryloxy group, a heterocyclic group, or a heterocyclic oxy group is represented.
As the alkyl group, aryl group, alkenyl group, alkoxy group, or aryloxy group in the substituent R ¹¹ , the alkyl group, aryl group, alkenyl group, alkoxy group, or aryloxy group in the aforementioned substituents R ^{25 to} R ^{29 is used} . And preferred examples are also the same.
Preferable specific examples of the substituent R ¹¹ include an alkyl group containing two or more oxygen atoms (—O—) in the chain, and an alkoxyl group by containing two or more —O— in the chain. The alkoxyl group formed by containing two or more —O— in the chain is linear, branched or monocyclic having 2 to 18 carbon atoms and interrupted by two or more —O—. or include condensed polycyclic alkoxyl _{group, -O- (CH 2 -O) k} -CH 3 ( where k is 2 to _{10), - O-CH 2} -CH 2 -O-CH 2 -O —CH ₂ —CH ₃ , —O— (CH ₂ —CH ₂ —O) _n —CH ₃ (where n is 2 to 8), —O— (CH ₂ —CH ₂ —CH ₂ —O) _m -CH ₂ (wherein m is 5 _{2), - O-CH 2} -CH 2 -O-CH 2 -CH (CH 3) -O-CH 2 -CH 3, -O-CH 2 - CH- _{(OCH 3)} but ₂ and the like, but is not limited thereto.

In general formula (II-5) and general formula (II-6), U is the same as in general formula (II-4).
More specifically, as A, naphthyl group, anthryl group, phenanthrenyl group, naphthacenyl group, pyrenyl group, phenylnaphthyl group, indenyl group, azulenyl group, acenaphthylenyl group, acenaphthenyl group, furanyl group, pyrrolyl group, thienyl group, Indolyl group, benzofuranyl group, benzothienyl group, indenyl group, quinolinyl group, isoquinolinyl group, carbazolyl group, dibenzofuranyl group, dibenzothiophenyl group, fluorenyl group dibenzo [b, e] [1,4] dioxinyl group, phenoxathi Inyl group, phenothiazinyl group, thiantenyl group, xanthenyl group, thioxanthenyl group, phenoxazinyl group, phenazinyl group, acridinyl group, xanthonyl group, benzoxazolyl group, benzothiazolyl group, benzimidazolyl group, Danazolyl group, 1,2-benzisoxazolyl group, phenananthridinyl group, phenanthrolinyl group, pyrazinyl group, pyridazinyl group, iminostilbenyl group, acridonyl group, triphenylamine group, N-phenylpyrrole But may be mentioned, but not limited thereto.

Ar ¹ represents a group or a heterocyclic group represented by the following (II-2).

In general formula (II-2), R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ and R ²⁹ are each independently a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an acyl group, an alkoxy group, an aryloxy group, An acyloxy group, an alkoxycarbonyloxy group, an alkylthio group, an arylthio group, an alkylamino group, a dialkylamino group, an arylamino group, a diarylamino group, an alkylarylamino group, or a halogen atom. R ^{25 to} R ²⁹ may integrally form an aromatic ring.

Examples of the heterocyclic group in the case where Ar ¹ represents a heterocyclic group include an aromatic or aliphatic heterocyclic group having 2 to 24 carbon atoms, including a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom. 2-thienyl group, 2-benzothienyl group, naphtho [2,3-b] thienyl group, 3-thianthrenyl group, 2-thianthrenyl group, 2-furyl group, 2-benzofuryl group, pyranyl group, iso Benzofuranyl group, chromenyl group, xanthenyl group, phenoxathiinyl group, 2H-pyrrolyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, indolizinyl group, isoindolyl group, 3H -Indolyl group, 2-indolyl group, 3-indolyl group, 1H-indazolyl group, purinyl group, 4H-quinolidinyl group , Isoquinolyl group, quinolyl group, phthalazinyl group, naphthyridinyl group, quinoxanilyl group, quinazolinyl group, cinnolinyl group, pteridinyl group, 4aH-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, β-carbolinyl group, phenanthridinyl group 2-acridinyl group, perimidinyl group, phenanthrolinyl group, phenazinyl group, phenalsadinyl group, isothiazolyl group, phenothiazinyl group, isoxazolyl group, furazanyl group, 3-phenixazinyl group, isochromanyl group, chromanyl group, pyrrolidinyl group, pyrrolinyl group Imidazolidinyl group, imidazolinyl group, pyrazolidinyl group, pyrazolinyl group, piperidyl group, piperazinyl group, indolinyl group, isoindolinyl group, quinuclidinyl group, morpholinyl group, thioxa Tolyl group, 4-quinolinyl group, 4-isoquinolyl group, 3-phenothiazinyl group, 2-phenoxathiinyl group, 3-coumarinyl of the group and the like, but is not limited thereto.

The monovalent group such as an alkyl group, an aryl group, or a heterocyclic group in Ar ¹ may further have a substituent. Examples of the substituent that can be introduced include an alkyl group, an aryl group, an alkenyl group, and an acyl group. Group, alkoxy group, aryloxy group, acyloxy group, alkoxycarbonyloxy group, alkylthio group, arylthio group, alkylamino group, dialkylamino group, arylamino group, diarylamino group, alkylarylamino group, halogen atom, etc. It is done.
Although the preferable specific example of a compound represented by general formula (II) in this invention is given to the following, this invention is not limited to these.

  Examples of the specific polymerization initiator represented by the general formula (II) include paragraph numbers [0103] to [0127] of JP-A-2006-206799 and paragraph numbers [0101] to [0105 of JP-A-2008-31280. And the like can be used in the present invention. The specific polymerization initiator can be synthesized by the method described in each of the above publications.

In the photocurable composition of the present invention, (ii) only one type of specific photopolymerization initiator may be used, or two or more types may be used in combination.
The content of the specific polymerization initiator represented by the general formula (II) in the photocurable composition of the present invention is preferably in the range of 0.1 to 30% by mass, and 0.2 to 20% by mass. A range is more preferable.

[Other polymerization initiators]
The photocurable composition of the present invention is required to contain at least the specific polymerization initiator as a photopolymerization initiator. However, as long as the effects of the present invention are not impaired, other photopolymerization initiators are used in combination. May be.
Known polymerization initiators that can be used in combination include radical polymerization initiators: (a) aromatic ketones, (b) acylphosphine compounds, (c) aromatic onium salt compounds, (d) organic peroxides (E) thio compounds, (f) hexaarylbiimidazole compounds, (g) ketoxime ester compounds, (h) borate compounds, (i) azinium compounds, (j) metallocene compounds, (k) active ester compounds, 1) A compound having a carbon halogen bond, and (m) an alkylamine compound.
As an example of the radical polymerization initiator mentioned above, the radical polymerization initiator described in paragraph number [0135]-[0208] of the specification of Unexamined-Japanese-Patent No. 2006-085049 can be mentioned, for example.
As described above, the radical polymerization initiators may be used alone or in combination of two or more.

  The content of the polymerization initiator in the photocurable composition of the present invention is preferably 0.01 to 35 parts by mass with respect to 100 parts by mass of the polymerizable compound having an ethylenically unsaturated bond described later (iii). More preferably, it is 0.1 to 30 parts by mass, and further preferably 0.5 to 25 parts by mass. Here, the content of the polymerization initiator means the total content of the polymerization initiator including the specific polymerization initiator and other polymerization initiators that can be used in combination.

<(Iii) Polymerizable compound having an ethylenically unsaturated bond>
The photocurable composition of the present invention contains a polymerizable compound.
The polymerizable compound that can be suitably used in the present invention is a compound having an ethylenically unsaturated bond capable of radical polymerization, and any compound having at least one ethylenically unsaturated bond capable of radical polymerization in the molecule. Any type may be used, including those having chemical forms such as monomers, oligomers, and polymers.
Only one kind of radically polymerizable compound may be used, or two or more kinds thereof may be used in combination at an arbitrary ratio in order to improve desired properties. 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 include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and their salts, and ethylenically unsaturated groups. Examples thereof include radically polymerizable compounds such as anhydrides, 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, tetramethylolmethane 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, Shinzo Yamashita, “Cross-linking agent handbook”, (1981 Taiseisha); Kato Kiyomi, “UV / EB curing handbook (raw material)” (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 are described in JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, JP-A-10-863, JP-A-9-134011 and the like. And a photocurable polymerizable compound used in the photopolymerizable composition.

In order to further improve sensitivity, bleeding, and adhesion to a recording medium, a monoacrylate and a polyfunctional acrylate monomer or a polyfunctional acrylate oligomer having a molecular weight of 400 or more, preferably 500 or more are used in combination as a radical polymerizable compound. Is preferred. In particular, in an ink composition used for recording on a flexible recording medium such as a PET film or a PP film, a combination of a monoacrylate selected from the above compound group and a polyfunctional acrylate monomer or polyfunctional acrylate oligomer is used. It is preferable because the film strength can be increased while the film is flexible to improve adhesion.
Furthermore, an aspect in which at least three kinds of polymerizable compounds of monofunctional, bifunctional, and trifunctional or higher polyfunctional monomers are used in combination further maintains sensitivity, bleeding, and adhesion to a recording medium. This is preferable from the viewpoint of further improvement.

As monoacrylates, stearyl acrylate, isoamyl acrylate, isomystil acrylate, and isostearyl acrylate have high sensitivity and low shrinkage to prevent curling. preferable.
As the oligomer that can be used in combination with the monoacrylate, an epoxy acrylate oligomer and a urethane acrylate oligomer are particularly preferable.
Note that methacrylate has a lower skin irritation than acrylate.
Among the above compounds, when alkoxy acrylate is used in an amount of less than 70% by mass and the balance is acrylate, it is preferable because it has good sensitivity, bleeding characteristics, and odor characteristics.

The photocurable composition of the present invention contains the components (i) to (iii) as essential components. However, depending on the intended use of the photocurable composition, the effects of the present invention are not impaired. Other components known as additives can be used in combination.
Hereinafter, preferable optional components will be described with reference to an example in which the photocurable composition of the present invention is applied to an ink composition which is an optimal application.

<Colorant>
When applying the photocurable composition of the present invention to applications such as image portion formation of an ink composition or a lithographic printing plate, in order to improve the visibility of the image portion formed by the photocurable composition, Or when it is going to form a colored image using an ink composition, a coloring agent can be contained.

  The colorant that can be used in the present invention is not particularly limited, but (1) pigments and (2) oil-soluble dyes that are excellent in weather resistance and rich in color reproducibility are preferable. The known colorant can be selected and used. The colorant that can be suitably used in the ink composition of the present invention or the ink composition for inkjet recording functions as a polymerization inhibitor in a polymerization reaction that is a curing reaction from the viewpoint of not reducing the sensitivity of the curing reaction by actinic radiation. It is preferred to select compounds that do not.

(1) Pigment The pigment that can be used in the present invention is not particularly limited. For example, organic or inorganic pigments having the following numbers described in the color index can be used.
Examples of the red or magenta pigment include Pigment Red 3, 5, 19, 22, 31, 38, 43, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49: 1, and 53. : 1, 57: 1, 57: 2, 58: 4, 63: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 88, 104, 108, 112, 122, 123, 144 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange 13, 16, 20, 36, and the like.
Examples of the blue or cyan pigment include Pigment Blue 1, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17-1, 22, 27, 28, 29, 36. , 60, and the like.
Examples of the green pigment include Pigment Green 7, 26, 36, 50, and the like.
Examples of the yellow pigment include Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, and 137. 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193, and the like.
Examples of the black pigment include Pigment Black 7, 28, 26, and the like.
Examples of the white pigment include Pigment White 6, 18, 21, and the like.
These pigments can be appropriately selected and used according to the purpose.

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

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

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

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

  Each of the above dyes may exhibit yellow, magenta, and cyan colors only after a part of chromophore (chromogenic atomic group) is dissociated. In this case, the counter cation may be an alkali metal or ammonium. Such inorganic cations may be used, and organic cations such as pyridinium and quaternary ammonium salts may be used, and furthermore, polymer cations having such a structure may be used.

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

In the present invention, the oil-soluble dye may be used alone or in combination of several kinds.
Further, when an oil-soluble dye is used as a colorant, other water-soluble dyes, disperse dyes, pigments, and other colorants can be used in combination as long as the effects of the present invention are not impaired. .

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

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

  It is also possible to add a dispersant when dispersing the colorant. The type of the dispersant is not particularly limited, but a polymer dispersant is preferably used, and examples of the polymer dispersant include Solsperse series manufactured by Zeneca. Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. In the present invention, these dispersant and dispersion aid are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the colorant.

  In preparing the photocurable composition and ink composition of the present invention, the colorant may be blended by direct addition together with the respective components. However, in order to improve dispersibility, a colorant or a specific monofunctional compound in the present invention is used in advance. It can also be added after being added to a dispersion medium such as a (meth) acrylic acid derivative or other polymerizable compound used in combination, and uniformly dispersed or dissolved.

  In the present invention, in order to avoid the problem of deterioration of the solvent resistance of the image area over time, which is a concern when the solvent remains in the cured image, the colorant contains a specific monofunctional (meth) acrylic acid derivative. It is preferable to add and mix in advance with any one of the polymerizable compounds to be contained or a mixture thereof. In consideration of only dispersibility, it is preferable to select a monomer having the lowest viscosity as the polymerizable compound used for the addition of the colorant.

One or more colorants may be appropriately selected according to the intended use of the ink composition.
In the curable composition and ink composition of the present invention, when a colorant such as a pigment that remains in a solid state is used, the average particle diameter of the colorant particles is preferably 0.005 to 0.00. It is preferable to set the colorant, the dispersant, the dispersion medium, the dispersion conditions, and the filtration conditions so as to be 5 μm, more preferably 0.01 to 0.45 μm, and still more preferably 0.015 to 0.4 μm. . This particle size control is preferable because clogging of the head nozzle can be suppressed and ink storage stability, ink transparency, and curing sensitivity can be maintained.

  The content of the colorant in the photocurable composition and the ink composition of the present invention is appropriately selected depending on the purpose of use, but generally considering the physical properties of the ink and the colorability, generally the mass of the entire composition The content is preferably 1 to 10% by mass, and more preferably 2 to 8% by mass.

<Other ingredients>
If necessary, other components can be added to the photocurable composition of the present invention. Examples of other components include a polymerization inhibitor and a solvent.
(Polymerization inhibitor)
A polymerization inhibitor may be added from the viewpoint of enhancing the storage stability. In addition, when the photocurable composition of the present invention is used as an ink composition for ink jet recording, it is preferably heated and reduced in viscosity in the range of 40 to 80 ° C. to prevent head clogging due to thermal polymerization. In order to prevent this, it is preferable to add a polymerization inhibitor. The polymerization inhibitor is preferably added in an amount of 200 to 20,000 ppm based on the total amount of the ink composition of the present invention. Examples of the polymerization inhibitor include hydroquinone, benzoquinone, p-methoxyphenol, TEMPO, TEMPOL, and cuperon Al.

(solvent)
In view of the fact that the ink composition of the present invention and the ink composition for ink jet recording are radiation curable ink compositions, it is preferable that no solvent is contained so that the ink composition can react quickly and be cured immediately after landing of the ink composition. However, a predetermined solvent can be included as long as the curing rate of the ink composition is not affected. In the present invention, an organic solvent or water can be used as the solvent. In particular, the organic solvent can be added in order to improve the adhesion to the recording medium (support such as paper).
When the organic solvent is added, for example, when the photocurable composition of the present invention is used in an ink composition, for example, 0.1 to 5% by mass is preferable with respect to the total mass. More preferably, it is the range of 0.1-3 mass%.

(Other ingredients)
In addition, a known compound can be added to the photocurable composition of the present invention as necessary. For example, surfactants, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins, washes, etc. are appropriately selected and added. be able to. In order to improve the adhesion to a recording medium such as polyolefin or PET, it is also preferable to contain a tackifier that does not inhibit the polymerization. Specifically, a high molecular weight adhesive polymer described in JP-A-2001-49200, pages 5 to 6 (for example, (meth) acrylic acid and an alcohol having an alkyl group having 1 to 20 carbon atoms). An ester, a copolymer of (meth) acrylic acid and an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer of an ester of (meth) acrylic acid and an aromatic alcohol having 6 to 14 carbon atoms), and polymerizability. Examples thereof include a low molecular weight tackifying resin having an unsaturated bond.
In addition, various resin additives such as thermoplastic polymer compounds, fillers, antifoaming agents, thickeners, flame retardants, antioxidants, stabilizers and the like are usually used as long as the effects of the present invention are not impaired. Can be added within the range of use.

  The photocurable composition of the present invention is a radiation curable ink composition, image forming materials such as three-dimensional stereolithography, holography, lithographic printing plates, color proofs, photoresists and color filters, paints, adhesives, etc. It can be used for photo-curing resin materials.

[Ink composition]
The ink composition of the present invention includes the above-described photocurable composition of the present invention.
That is, the ink composition of the present invention comprises (i) a sensitizing dye represented by the general formula (IC) which is a preferred embodiment of the sensitizing dye (specific sensitizing dye) represented by the general formula (I) , (Ii) a photopolymerization initiator represented by the general formula (II) and (iii) a polymerizable compound having an ethylenically unsaturated bond, and if necessary, a colorant and the like. .
These components are preferably (i) a specific sensitizing dye with respect to the total mass of the ink composition of the present invention, and preferably 0.1 wt% to 20 wt%, more preferably 0.3 wt% to 10 wt%. % By weight, (ii) the specific polymerization initiator is preferably from 0.01 to 35% by weight, more preferably from 0.1 to 30% by weight, more preferably from 0 to (iii) the polymerizable compound. 0.5 to 30% by weight, (iii) The polymerizable compound is preferably 10% to 95% by weight, more preferably 30% to 93% by weight, still more preferably 50% to 90% by weight, When a colorant is used, the colorant is preferably 1 to 20% by weight, more preferably 2 to 8% by weight, and it is appropriate that the total amount of each component is 100% by weight. It is.

-Properties of ink composition-
In the ink composition of the present invention, low viscosity is more advantageous for triplet energy transfer sensitization from the viewpoint of ease of molecular diffusion, and since it is excellent in stability as a solution, it is used as an ink for ink jet recording. It can be preferably used. The preferred physical properties in the usage mode as the ink for inkjet recording will be described.
When the ink composition is used as an ink for ink jet recording, the viscosity is preferably 7 to 30 mPa at the temperature at the time of ejection (for example, 40 to 80 ° C., preferably 25 to 50 ° C.) in consideration of the ejectability. · S, more preferably 7 to 25 mPa · s. For example, the viscosity of the ink composition of the present invention at room temperature (25 to 30 ° C.) is preferably 35 to 500 mPa · s, more preferably 35 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. Furthermore, ink bleeding at the time of ink droplet landing can be suppressed, and as a result, image quality is improved.

  The surface tension of the ink composition of the present invention is preferably 20 to 30 mN / m, more preferably 23 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.

[Inkjet recording method]
Next, an ink jet recording method of the present invention and an ink jet recording apparatus applicable to the method will be described.
In the inkjet recording method of the present invention, the ink composition of the present invention is ejected onto a recording medium (support, recording material, etc.) for inkjet recording, and the ink composition ejected onto the recording medium is active. In this method, an image is formed by irradiating radiation and curing the ink.

That is, the inkjet 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, And a step of curing the ink composition.
By including the steps (1) and (2), the ink jet recording method of the present invention forms an image with the ink composition cured on the recording medium.
Here, the peak wavelength of the active radiation in the step (2) is preferably 200 nm to 600 nm, more preferably 300 nm to 450 nm, and more preferably 350 nm to 420 nm. The output of active radiation is preferably 2,000 mJ / cm ² or less, more preferably ^{10mJ / cm 2 ~2,000mJ / cm 2} , more preferably 20mJ ^/ cm 2 ~1,000mJ ^/ cm ² , particularly preferably 50 mJ / cm ^{2 to} 800 mJ / cm ² .

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

<Inkjet recording apparatus>
There is no restriction | limiting in particular as an inkjet recording device used for the recording method of this invention, The well-known inkjet recording device which can achieve the target resolution can be selected arbitrarily and can be used. That is, any known inkjet recording apparatus including a commercially available product can eject ink onto the recording medium in step (1) of the inkjet recording method of the present invention.
Examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and an actinic radiation source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head has a multi-size dot of 1 to 100 pl, preferably 8 to 30 pl, for example, 320 × 320 to 4000 × 4000 dpi, preferably 400 × 400 to 1600 × 1600 dpi, more preferably 720 × 720 dpi. It can drive so that it can discharge with the resolution of. In the present invention, dpi represents the number of dots per 2.54 cm.

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

Next, (2) the step of curing the ink composition by irradiating the discharged ink composition with actinic radiation will be described.
The ink composition ejected on the recording medium is cured by irradiation with actinic radiation. This is because the polymerization initiator contained in the ink composition of the present invention is decomposed by irradiation with actinic radiation to generate radicals, acids, bases and other starting species, and the function of the starting species causes a specific monofunctionality ( This is because the polymerization reaction of the (meth) acrylic acid derivative and other polymerizable compound used in combination as required occurs and is accelerated, and the ink composition is cured. At this time, if a sensitizing dye is present together with the polymerization initiator in the ink composition, the sensitizing dye in the system absorbs actinic radiation to be in an excited state and promotes decomposition of the polymerization initiator by contacting with the polymerization initiator. And achieve a more sensitive curing reaction.

Here, α rays, γ rays, electron beams, X rays, ultraviolet rays, visible light, infrared rays, or the like can be used as the active radiation used. Although the peak wavelength of actinic radiation is based also on the absorption characteristic of a sensitizing dye, it is preferable that it is 200-600 nm, for example, it is more preferable that it is 300-450 nm, and it is further more preferable that it is 350-420 nm.
In the present invention, the polymerization initiating system has sufficient sensitivity even with low-power actinic radiation. Thus, the output of the active radiation is preferably 2,000 mJ / cm ² or less, more preferably from 10 to 2,000 mJ / cm ^2, more preferably, be 20 to 1,000 mJ / cm ² Particularly preferably, it is 50 to 800 mJ / cm ² .
The active radiation, the illumination intensity on the exposed surface is, for example, 10 to 2,000 mW / cm ^2, preferably, it is suitable to be irradiated at 20 to 1,000 mW / cm ^2.

  Mercury lamps and gas / solid lasers are mainly used as actinic radiation sources, and mercury lamps and metal halide lamps are widely known as light sources used for curing UV photocurable ink jet recording inks. Yes. However, from the viewpoint of environmental protection, mercury-free is strongly desired, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long life, have high efficiency, and are low in cost, and are expected as light sources for photocurable ink jets.

Further, a light emitting diode (LED) and a laser diode (LD) can be used as the active radiation source. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. When even shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit actinic radiation centered between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. The actinic radiation source particularly preferred in the present invention is a UV-LED, particularly preferably a UV-LED having a peak wavelength at 340 to 370 m.
It is preferable that maximum illumination intensity of the LED on a recording medium is ^{10mW / cm 2 ~2,000mW / cm 2} , more preferably ^{20mW / cm 2 ~1,000mW / cm 2} , particularly preferably is a ^{50mW / cm 2 ~800mW / cm 2} .

In the present invention, the active radiation in the step (2) is an ultraviolet ray having an emission peak wavelength in the range of 340 nm to 370 nm and a maximum illuminance on the surface of the recording medium of 10 to 2,000 mW / cm ^2. It is preferable that it is an ultraviolet-ray irradiated with the light emitting diode (UV-LED) to generate | occur | produce.

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

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

Here, the actinic radiation source used for curing the ink or preferred irradiation conditions thereof are also the same as those described in the ink jet recording method.
The ink composition of the present invention is cured with high sensitivity by actinic radiation, and can form a hydrophobic region excellent in adhesion to the support and film quality. For this reason, in addition to the formation of colored images, marking, etc., it can also be used, for example, for the formation of the image portion of a lithographic printing plate. By applying to this application, a lithographic plate having high image quality and excellent printing durability. It is also possible to obtain a printed version.
The ink composition of the present invention is excellent for ink jet recording for the reasons described above, but it is needless to say that it is also useful as a commonly used ink composition.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to the form in these Examples. The following examples relate to UV ink jet ink compositions for each color. 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 white UV inkjet ink composition.
(White ink composition)
・ Light acrylate LA 22.9 parts [Lauryl acrylate: monofunctional acrylate]
Actylane 421 (Akcros acrylate monomer) 27.0 parts [propoxylated neopentyl glycol diacrylate: bifunctional acrylate]
-Photomer 2017 (UV diluent manufactured by EChem) 15.0 parts-Solsperse 36000 (dispersant made by Noveon) 2.0 parts-15.0 parts-MICROLITH WHITE R-A (pigment manufactured by Ciba Specialty Chemicals)
-Genorad 16 (stabilizer manufactured by Rahn) 0.05 parts-Rapi-Cure DVE-3 8.0 parts (vinyl ether manufactured by ISP Europe)
Specific sensitizing dye [Compound A: Structure below] 4.0 parts Specific polymerization initiator [Compound (1): Structure below] 8.5 parts (Photopolymerization initiator manufactured by Ciba Specialty Chemicals)
・ Irgacure 907 [specific polymerization initiator] 6.0 parts (Ciba Specialty Chemicals photopolymerization initiator)
・ Byk 307 (defoamer manufactured by BYK Chemie) 0.05 parts

<Evaluation of ink composition>
<Evaluation of Ink> The ink composition obtained in Example 1 was ejected onto a sheet made of polyvinyl chloride and irradiated by passing it at a specific speed under the light of an ultraviolet light emitting diode (UV-LED). The ink was cured to obtain a printed matter.
In this example, the ink was ejected by a commercially available ink jet recording apparatus having a piezo ink jet nozzle, and NCCU033 manufactured by Nichia Chemical was used as a light emitting diode (UV-LED) for curing. 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, and a power of 0.3 W / cm ² is obtained on the surface of the recording medium (hereinafter also referred to as a medium). The exposure time after the droplet ejection and the exposure time can be changed according to the transport speed of the medium and the distance between the head and the LED in the transport direction. In this embodiment, the exposure is performed about 0.5 seconds after landing.
The exposure energy on the medium can be adjusted between 0.01 and 15 J / cm ² depending on the setting of the distance to the medium and the conveyance speed.
At this time, the following evaluation was performed.

-Curing sensitivity-
Curing sensitivity was defined by the exposure energy at which the surface was not sticky after printing.
The presence or absence of stickiness on the surface after printing was determined by pressing plain paper (copy paper C2 manufactured by Fuji Xerox Co., Ltd.) immediately after printing.
The lower the energy value, the higher the curing sensitivity, and the following criteria were used.

<Evaluation criteria>
A: Surface stickiness disappeared at an exposure energy of 1000 mJ / cm ² or less.
◯: Surface stickiness disappeared when the exposure energy exceeded 1000 mJ / cm ^{2 and} was 1500 mJ / cm ² or less.
△: beyond the exposure energy 1500mJ / cm ^2, there is no more stickiness of 2000mJ / cm ² or less at the surface.
X: An exposure energy exceeding 2500 mJ / cm ² was required to eliminate surface stickiness.

-Evaluation of ink adhesion-
The image forming surface that had been sprayed and hardened was cut with a cutter, a cellophane tape was applied, and the cellophane tape was peeled off. At this time, whether the cured ink remained on the medium was determined based on the following criteria.
In addition, as for the printed matter used for the adhesive test, all used what was exposed with the exposure energy of 2000 mJ / cm < ² > in the sclerosis | hardenability (tack free sensitivity) test.
<Evaluation criteria>
○: All ink remains.
Δ: Ink around the cut portion has moved to the tape.
X: Almost all in close contact with the tape has moved to the tape side.

[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)
Light acrylate L-A 19.4 parts Actylene 421 (Akcros acrylate monomer) 33.5 parts Photomer 2017 (EChem UV diluent) 20.0 parts Solsperse 32000 (Noveon dispersant) 0 .4 parts-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)
Specific sensitizer [compound A: the above structure] 4.0 parts Specific polymerization initiator [compound (2): the following structure] 6.0 parts (Photopolymerization initiator manufactured by Ciba Specialty Chemicals)
Byk 307 (antifoaming agent manufactured by BYK Chemie) 0.05 parts The ink composition obtained in Example 2 was evaluated in the same manner as in Example 1.
The results are shown in Table 1 below.

Example 3
The following components were stirred with a high-speed water-cooled stirrer to obtain a cyan UV inkjet ink composition.
(Cyan ink composition)
Light acrylate L-A 22.9 parts Actylene 421 (Akcros acrylate monomer) 30.0 parts Photomer 2017 (EChem UV diluent) 20.0 parts Solsperse 32000 (Noveon dispersant) 0 .4 parts ・ Irgalite Blue GLVO 3.6 parts (Ciba Specialty Chemicals pigment)
-Genorad 16 (stabilizer manufactured by Rahn) 0.05 part-Rapi-Cure DVE-3 (vinyl ether manufactured by ISP Europe)
8.0 parts / specific sensitizer [compound B: structure below] 4.0 parts / specific polymerization initiator [compound (3): structure below] 6.0 parts / byk 307 (defoamer manufactured by BYK Chemie) 0.05 part The ink composition obtained in Example 3 was evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

Example 4
The following components were stirred with a high-speed water-cooled stirrer to obtain a yellow UV inkjet ink composition.
(Yellow color ink composition)
Light acrylate LA 14.0 parts Actylene 421 (Akcros acrylate monomer) 42.9 parts Photomer 2017 (EChem UV diluent) 20.0 parts Solsperse 32000 (Noveon dispersant) 0 .4 parts · Chromophthalal Yellow LA 3.6 parts (Ciba Specialty Chemicals pigment)
-Genorad 16 (stabilizer manufactured by Rahn) 0.05 parts-Rapi-Cure DVE-3 4.0 parts (vinyl ether manufactured by ISP Europe)
Specific sensitizing dye [Compound C: Structure below] 4.0 parts Specific polymerization initiator [Compound (4): Structure below] 6.0 parts Byk 307 (antifoam manufactured by BYK Chemie) 0.05 parts The ink composition obtained in Example 4 was evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

Example 5
The following components were stirred with a high-speed water-cooled stirrer to obtain a black UV inkjet ink composition.
(Black ink composition)
Light acrylate L-A 26.9 parts Actylene 421 (Akcros acrylate monomer) 31.0 parts Photomer 2017 (EChem UV diluent) 20.0 parts Solsperse 32000 (Noveon 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)
Specific sensitizer [Compound D: Structure below] 4.0 parts Specific polymerization initiator [Compound (5): Structure below] 6.0 parts Byk 307 (antifoam manufactured by BYK Chemie) 0.05 parts The ink composition obtained in Example 5 was evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

Example 6
The following components were stirred with a high-speed water-cooled stirrer to obtain a black UV inkjet ink composition.
(Black ink composition)
Light acrylate L-A 26.9 parts Actylene 421 (Akcros acrylate monomer) 31.0 parts Photomer 2017 (EChem UV diluent) 20.0 parts Solsperse 32000 (Noveon 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)
Specific sensitizer [Compound E: Structure below] 4.0 parts Specific polymerization initiator [Compound (6): Structure below] 6.0 parts Byk 307 (defoamer manufactured by BYK Chemie) 0.05 parts The ink composition obtained in Example 6 was evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

Example 7
The following components were stirred with a high-speed water-cooled stirrer to obtain a black UV inkjet ink composition.
(Black ink composition)
Light acrylate L-A 22.9 parts Actylene 421 (Akcros acrylate monomer) 31.0 parts Photomer 2017 (EChem UV diluent) 20.0 parts Solsperse 32000 (Noveon 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)
Specific sensitizer [Compound A: the structure] 4.0 parts Specific polymerization initiator [Compound (4): the structure] 6.0 parts Irgacure TPO 4.0 parts (Photopolymerization started by Ciba Specialty Chemicals) Agent)
Byk 307 (defoamer manufactured by BYK Chemie) 0.05 part The ink composition obtained in Example 7 was evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[Comparative Examples 1-6]
Specific sensitizer in Example 1 Compound A, specific polymerization initiator A white ink composition was prepared in the same manner as in Example 1 except that the compound (1) was replaced with the sensitizer and polymerization initiator shown in Table 1. Adjustments were made and evaluated as in Example 1.
The structures of the comparative sensitizing dye F, the comparative sensitizing dye G, and the comparative polymerization initiator C-1 used in the comparative examples are shown below.

As is clear from Table 1, all of the ink compositions of Examples 1 to 7 to which the curable composition of the present invention was applied were cured with high sensitivity and excellent in adhesion to the recording medium. Moreover, when the cured image formed with the ink composition of each color was visually observed, it was found that the color reproducibility was excellent in any hue.
On the other hand, the white ink compositions of Comparative Examples 1 to 7 that do not contain the sensitizing dye according to the present invention or use the comparative sensitizing dye. Both curing sensitivity and adhesion were inferior to those of the examples. In Comparative Examples 3 to 7 using the comparative sensitizing dye, the color reproducibility of the white image is not good because the cured image formed with the white ink is yellow, which is estimated to be caused by the comparative sensitizing dye. It was.

Claims (7)

(I) a sensitizing dye represented by the following general formula (I-C), (ii ) a photopolymerization initiator represented by the following formula (II), a polymerizable compound having a (iii) an ethylenically unsaturated bond And a photocurable composition containing.


(In the general formula ^{(I-C), R 1C} , R 2C, R 3C, R 4C, R 5C, R 6C, each independently ^{R 7C} and ^{R 8C,} represent a hydrogen atom, an alkyl group, or a halogen atom. )


In the general formula (II), A represents a divalent aromatic fused ring group having 4 to 16 carbon atoms, and may be an aromatic heterofused ring group. Ar ¹ represents a group represented by the following general formula (II-2) or a heterocyclic group.
R ²¹ and R ²² each independently represents an alkyl group, an aryl group, or an alkenyl group, and R ²¹ and R ²² are bonded to each other to form an alkylene group having 2 to 8 carbon atoms and 3 to 9 carbon atoms. May be formed, or an azaalkylene group having 3 to 9 carbon atoms. R ²³ and R ²⁴ each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, or COR ^10, which are bonded to each other to form an alkylene group having 2 to 6 carbon atoms, or 2 to 2 carbon atoms. A oxaalkylene group having 6 carbon atoms, a thiaalkylene group having 2 to 6 carbon atoms, or an azaalkylene group having 2 to 6 carbon atoms may be formed. Here, R ¹⁰ represents an alkyl group, an aryl group, an alkenyl group, an alkoxy group, or an aryloxy group.


In general formula (II-2), R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ and R ²⁹ are each independently a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an acyl group, an alkoxy group, an aryloxy group, An acyloxy group, an alkoxycarbonyloxy group, an alkylthio group, an arylthio group, an alkylamino group, a dialkylamino group, an arylamino group, a diarylamino group, an alkylarylamino group, or a halogen atom. R ^{25 to} R ²⁹ may integrally form an aromatic ring. R in the general formula (IC) ^1c , R ^2c , R ^3c And R ^4c Each independently represents a hydrogen atom, an alkyl group, or a halogen atom, and R ^5c , R ^6c , R ^7c And R ^8c The photocurable composition according to claim 1, wherein each independently represents a hydrogen atom or an alkyl group. An ink composition comprising the photocurable composition according to claim 1 . Furthermore, the ink composition of Claim 3 containing a coloring agent. The ink composition according to claim 3 or 4 , which is for inkjet recording. (A) a step of discharging the ink composition according to claim 5 onto a recording medium; and (b) a step of irradiating the discharged ink composition with active radiation to cure the ink composition. An ink jet recording method comprising: The active radiation, emission peak wavelength is in the range of 340Nm～370nm, and is illuminated by the light emitting diodes that emit ultraviolet maximum illuminance of the surface of the recording medium becomes 10mW ^/ cm ² ~2,000mW ^/ cm 2 The inkjet recording method according to claim 6 , wherein the ultraviolet ray is ultraviolet light.