JP2017186481A - Radiation-curable inkjet composition and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-curable inkjet composition achieving a low viscosity and curability of the composition, having excellent responsiveness (adhesiveness) to various recording media and excellent rubbing resistance of a recorded image, and a recording method using the composition.SOLUTION: The radiation-curable inkjet composition according to the present invention comprises a polymerizable compound A represented by general formula (1) CH=CR-COOR-O-CH=CH-R, a polymerizable compound B represented by general formula (2) below, and an epoxy (meth)acrylate, and contains the polymerizable compound A by 12 mass% or more. In formula (1), Rrepresents a hydrogen atom or a methyl group; Rrepresents a divalent organic residue having 2 to 20 carbon atoms; and Rrepresents a hydrogen atom or a monovalent organic residue having 1 to 11 carbon atoms. In formula (2), n represents an integer of 2 to 6.SELECTED DRAWING: None

Description

  The present invention relates to a radiation curable ink jet composition and a recording method using the composition.

  In recent years, in order to form an image having high water resistance, solvent resistance, and abrasion resistance on the surface of a recording medium, a radiation curable ink jet composition that is cured when irradiated with radiation in an ink jet recording method has been used. ing. Generally, a radiation curable inkjet composition is composed of a polymerizable compound such as a monofunctional monomer or a polyfunctional monomer, a photopolymerization initiator, a pigment, and the like.

  The radiation curable inkjet composition is often recorded on a recording medium that does not absorb or hardly absorbs the composition such as plastic, glass, and coated paper. Therefore, it is required that the curability of the composition and the adhesion and abrasion resistance of an image recorded on a recording medium are good. Further, since the radiation curable inkjet composition is used in an inkjet recording method, it is also required to have a low viscosity.

  For example, Patent Document 1 discloses a radiation curable ink composition containing phenoxyethyl acrylate and epoxy acrylate. In this radiation curable ink composition, by setting the hydroxyl value in the ink within a specific range, the tackiness of the recorded image can be reduced, and an image having excellent storage stability and good gloss can be obtained. It is disclosed.

  Patent Document 2 discloses a radiation curable inkjet ink composition containing a predetermined amount of a compound having both a vinyl group and a (meth) acryl group in the molecule and N-vinylcaprolactam. It is disclosed that the radiation curable ink jet ink composition is excellent in all of abrasion resistance, adhesion, and alcohol resistance.

JP 2011-195724 A JP 2012-116934 A

  However, the radiation curable ink compositions disclosed in Patent Document 1 and Patent Document 2 have low ink viscosity and curability, compatibility with various recording media (adhesion), and recorded images. It could not be said that the rub resistance and the like were sufficiently satisfactory.

  Accordingly, some aspects of the present invention solve at least a part of the above-described problems, thereby reducing the viscosity and curability of the composition, compatibility with various recording media (adhesion), and recording. The present invention provides a radiation curable ink jet composition excellent in abrasion resistance of a printed image, and a recording method using the composition.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

（式（２）中、ｎは２〜６の整数を表す。） [Application Example 1]
One aspect of the radiation curable inkjet composition according to the present invention is:
Polymerizable compound A represented by the following general formula (1);
Polymerizable compound B represented by the following general formula (2);
Epoxy (meth) acrylate,
A radiation curable inkjet composition containing
12% by mass or more of the polymerizable compound A is contained.
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (1)
(In the formula (1), ^{R 1} is a hydrogen atom or a methyl group, ^{R 2} is a divalent organic residue having 2 to 20 carbon atoms, ^{R 3} is a monovalent hydrogen atom or a C 1 to 11 This is an organic residue.)

(In formula (2), n represents an integer of 2 to 6)

  According to the radiation curable inkjet composition of Application Example 1, by containing both the polymerizable compound B represented by the general formula (2) and the epoxy (meth) acrylate, the compatibility with various recording media ( Excellent adhesion). On the other hand, the viscosity of the composition is likely to increase due to the hydroxyl group derived from epoxy (meth) acrylate. And when polymeric compound B is solid at normal temperature, the viscosity of a composition tends to rise further. Therefore, when the polymerizable compound A represented by the general formula (1) is contained in an amount of 12% by mass or more, the composition has a low viscosity, which is suitable for an ink jet recording method. Moreover, since the reactivity of epoxy (meth) acrylate improves by containing the polymeric compound A 12 mass% or more, not only the compatibility (adhesiveness) to various recording media improves, but also sclerosis | hardenability. Further, the abrasion resistance is further improved.

[Application Example 2]
In the radiation curable inkjet composition of Application Example 1,
The content of the polymerizable compound A may be 40% by mass or less.

  According to the radiation curable inkjet composition of Application Example 2, not only the effects of Application Example 1 described above can be achieved, but also the storage stability of the composition can be maintained in an excellent state.

[Application Example 3]
In the radiation curable inkjet composition of Application Example 1 or Application Example 2,
Content of the said polymeric compound B can be 5 mass% or more and 15 mass% or less.

  According to the radiation curable inkjet composition of Application Example 3, the composition has excellent adhesion to the recording medium and excellent recorded image abrasion resistance.

[Application Example 4]
In the radiation curable inkjet composition according to any one of Application Examples 1 to 3, the content of the epoxy (meth) acrylate may be 3% by mass or more and 15% by mass or less.

  According to the radiation curable inkjet composition of Application Example 4, the adhesiveness to various recording media is excellent.

[Application Example 5]
In the radiation curable inkjet composition of any one of Application Examples 1 to 4, the monofunctional (meth) acrylate having an aromatic skeleton may further be contained in an amount of 20% by mass to 50% by mass.

  According to the radiation curable inkjet composition of Application Example 5, the solubility of the polymerization initiator tends to be good, and the curability is further improved. In particular, when an acylphosphine oxide polymerization initiator or a thioxanthone polymerization initiator is used, the solubility tends to be good.

[Application Example 6]
In the radiation curable inkjet composition of any one of Application Examples 1 to 5, the epoxy (meth) acrylate can have two (meth) acryloyl groups in one molecule.

  According to the radiation curable inkjet composition of Application Example 6, since the epoxy (meth) acrylate having two (meth) acryloyl groups in one molecule contains an appropriate crosslinking density in a recorded image, recording is performed. The image has an appropriate hardness.

[Application Example 7]
In the radiation curable inkjet composition of any one of Application Examples 1 to 6, the epoxy (meth) acrylate may have an aliphatic skeleton or an alicyclic skeleton.

  According to the radiation curable inkjet composition of Application Example 7, the recording image has an appropriate hardness by containing an epoxy (meth) acrylate having an aliphatic skeleton or an alicyclic skeleton.

[Application Example 8]
In the radiation curable inkjet composition according to any one of Application Examples 1 to 7, the epoxy (meth) acrylate has a mass average molecular weight of 2000 or less and a single viscosity of 2000 mPa · s or less at 25 ° C. be able to.

  According to the radiation curable inkjet composition of Application Example 8, since the increase in viscosity of the composition can be reduced, the inkjet recording method is more suitable.

[Application Example 9]
One aspect of the recording method according to the present invention is:
Recording is performed on a recording medium using the radiation curable inkjet composition according to any one of Application Examples 1 to 8.

  According to the recording method of Application Example 9, since the composition has a low viscosity, it is possible to realize good recording by the ink jet method. Further, it is possible to record an image having excellent adhesion to various recording media and excellent curability and abrasion resistance.

[Application Example 10]
In the recording method of application example 9,
The recording medium may contain any one of vinyl chloride, polyester, polycarbonate, and polyolefin resins.

  According to the recording method of Application Example 10, an image having excellent adhesion to various recording media including resins such as vinyl chloride, polyester, polycarbonate, and polyolefin can be recorded.

  Hereinafter, preferred embodiments of the present invention will be described. Embodiment described below demonstrates an example of this invention. In addition, the present invention is not limited to the following embodiments, and includes various modifications that are implemented within a range that does not change the gist of the present invention.

  The epoxy (meth) acrylate in the present invention refers to a compound obtained by reacting an unsaturated carboxylic acid and an epoxy compound. In this reaction, the epoxy group of the epoxy compound is ring-opened to form an ester bond with the unsaturated carboxylic acid.

  In the present specification, “(meth) acryloyl” means at least one of acryloyl and the corresponding methacryloyl, and “(meth) acrylate” means at least one of the acrylate and the corresponding methacrylate. , “(Meth) acryl” means at least one of acrylic and methacryl corresponding thereto.

  In the present specification, “curability” refers to a property of being cured by polymerization in the presence or absence of a polymerization initiator by irradiation with light. In the present invention, “curing” means that stickiness is not felt when a recorded material is touched with a finger, that is, tack-free.

  In this specification, “(record) image” indicates a print pattern formed from a group of dots, and includes text printing and solid printing.

1. Radiation curable inkjet composition The radiation curable inkjet composition according to the present embodiment (hereinafter also simply referred to as “inkjet composition” or “composition”) is a composition used by being ejected from an inkjet head by an inkjet method. is there. Hereinafter, a radiation curable inkjet ink composition will be described as one embodiment of the radiation curable inkjet composition, but the composition may be a composition other than the ink composition, for example, a composition used for 3D modeling. . Moreover, although it may describe as "ultraviolet ray curable type" as one embodiment of "radiation curable type", in this embodiment, if the composition is a radiation curable composition used by being cured by irradiation with radiation. Well, an ultraviolet curable composition or an ultraviolet curable composition may be read as a radiation curable composition or a radiation curable composition. Examples of radiation include ultraviolet rays, infrared rays, visible rays, and X-rays. As the radiation, ultraviolet rays are preferable because a radiation source is easily available and widely used, and a material suitable for curing by ultraviolet radiation is easily available and widely used.

（式（２）中、ｎは２〜６の整数を表す。） The radiation curable inkjet composition according to this embodiment includes a polymerizable compound A represented by the following general formula (1), a polymerizable compound B represented by the following general formula (2), and an epoxy (meth) acrylate. Is a radiation curable ink jet composition containing 12% by mass or more of the polymerizable compound A.
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (1)
(In the formula (1), ^{R 1} is a hydrogen atom or a methyl group, ^{R 2} is a divalent organic residue having 2 to 20 carbon atoms, ^{R 3} is a monovalent hydrogen atom or a C 1 to 11 This is an organic residue.)

(In formula (2), n represents an integer of 2 to 6)

  Hereinafter, components that can be included in the radiation-curable inkjet composition according to this embodiment will be described.

1.1. Polymerizable compound 1.1.1. Polymerizable compound A
The inkjet composition according to the present embodiment contains 12% by mass or more of the polymerizable compound A represented by the following general formula (1).
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (1)
(In the formula (1), ^{R 1} is a hydrogen atom or a methyl group, ^{R 2} is a divalent organic residue having 2 to 20 carbon atoms, ^{R 3} is a monovalent hydrogen atom or a C 1 to 11 This is an organic residue.)

  When the composition according to the present embodiment contains the polymerizable compound B represented by the general formula (2) and the epoxy (meth) acrylate described later, the adhesiveness to various recording media can be improved. However, sufficient characteristics cannot be obtained in terms of curability and viscosity reduction. In particular, the viscosity of the epoxy (meth) acrylate is likely to increase due to the hydroxyl group. In addition, when the polymerizable compound B represented by the general formula (2) is solid at room temperature, the viscosity is more likely to increase. When both of the polymerizable compound B represented by the general formula (2) and the epoxy (meth) acrylate are present in the system, the viscosity tends to increase synergistically. Therefore, when the polymerizable compound A represented by the general formula (1) is contained in an amount of 12% by mass or more, the composition has a low viscosity, which is suitable for an ink jet recording method. Moreover, since the reactivity of epoxy (meth) acrylate improves by containing the polymeric compound A 12 mass% or more, not only the adhesiveness to various recording media improves, but also sclerosis | hardenability and abrasion resistance. It will be further improved.

In the general formula (1), the divalent organic residue having 2 to 20 carbon atoms represented by R ² may be a linear, branched or cyclic substituted group having 2 to 20 carbon atoms. A good alkylene group, an optionally substituted alkylene group having an oxygen atom by an ether bond and / or an ester bond in the structure, and an optionally substituted divalent fragrance having 6 to 11 carbon atoms Group groups are preferred. Among these, C2-C6 alkylene groups such as ethylene group, n-propylene group, isopropylene group, and butylene group, oxyethylene group, oxy n-propylene group, oxyisopropylene group, and oxybutylene group An alkylene group having 2 to 9 carbon atoms having an oxygen atom due to an ether bond in the structure is preferably used.

In the general formula (1), the monovalent organic residue having 1 to 11 carbon atoms represented by R ³ may be linear, branched or cyclic substituted having 1 to 10 carbon atoms. A good alkyl group and an optionally substituted aromatic group having 6 to 11 carbon atoms are preferred. Among these, C6-C2 aromatic groups, such as a C1-C2 alkyl group which is a methyl group or an ethyl group, a phenyl group, and a benzyl group, are used suitably.

When each of the organic residues is an optionally substituted group, the substituent is divided into a group containing a carbon atom and a group not containing a carbon atom. First, when the substituent is a group containing a carbon atom, the carbon atom is counted in the carbon number of the organic residue. Examples of the group containing a carbon atom include, but are not limited to, a carboxy group and an alkoxy group. Next, examples of the group not containing a carbon atom include, but are not limited to, a hydroxyl group and a halo group.

  The lower limit of the content of the polymerizable compound A may be 12% by mass or more, preferably 13% by mass or more, more preferably 14% by mass or more, with respect to the total mass (100% by mass) of the composition. Especially preferably, it is 15 mass% or more. On the other hand, the upper limit of the content of the polymerizable compound A is preferably 40% by mass or less, more preferably 37% by mass or less, and still more preferably 35% by mass with respect to the total mass (100% by mass) of the composition. Hereinafter, it is particularly preferably 30% by mass or less. When the content of the polymerizable compound A is within the above range, the composition has a low viscosity, which is suitable for an ink jet recording method. Further, since the reactivity of the epoxy (meth) acrylate is improved, not only the adhesion to various recording media is improved, but also the curability and the abrasion resistance are further improved. If the lower limit value of the content of the polymerizable compound A is less than 12% by mass, the viscosity increases, so that it tends to be unsuitable for the ink jet recording method. Further, since the reactivity of the epoxy (meth) acrylate is lowered, the adhesion to the recording medium, the curability, and the abrasion resistance tend to be lowered.

Specific examples of the polymerizable compound A include, but are not limited to, for example, 2-vinyloxyethyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, 1-methyl-2-vinyloxyethyl (meth) acrylate, (Meth) acrylic acid 2-vinyloxypropyl, (meth) acrylic acid 4-vinyloxybutyl, (meth) acrylic acid 1-methyl-3-vinyloxypropyl, (meth) acrylic acid 1-vinyloxymethylpropyl, (meth) 2-methyl-3-vinyloxypropyl acrylate, 1,1′-dimethyl-2-vinyloxyethyl (meth) acrylate, 3-vinyloxybutyl (meth) acrylate, 1-methyl-2-vinyloxy (meth) acrylate Propyl, 2-vinyloxybutyl (meth) acrylate, 4-vinyloxycyclohexyl (meth) acrylate Sil, 6-vinyloxyhexyl (meth) acrylate, 4-vinyloxymethylcyclohexylmethyl (meth) acrylate, 3-vinyloxymethylcyclohexylmethyl (meth) acrylate, 2-vinyloxymethylcyclohexyl (meth) acrylate Methyl, p-vinyloxymethylphenylmethyl (meth) acrylate, m-vinyloxymethylphenylmethyl (meth) acrylate, o-vinyloxymethylphenylmethyl (meth) acrylate, 2- (vinyl) (meth) acrylate (Roxyethoxy) ethyl, 2- (vinyloxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxy) propyl (meth) acrylate, 2- (vinyloxyethoxy) isopropyl (meth) acrylate, (meth ) Acrylic acid 2- (vinyloxyisopropoxy) pro (Meth) acrylic acid 2- (vinyloxyisopropoxy) isopropyl, (meth) acrylic acid 2- (vinyloxyethoxyethoxy) ethyl, (meth) acrylic acid 2- (vinyloxyethoxyisopropoxy) ethyl, (meta ) 2- (vinyloxyisopropoxyethoxy) ethyl acrylate, 2- (vinyloxyisopropoxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyethoxy) propyl (meth) acrylate, (meth) acryl 2- (vinyloxyethoxyisopropoxy) propyl acid, 2- (vinyloxyisopropoxyethoxy) propyl (meth) acrylate, 2- (vinyloxyisopropoxyisopropoxy) propyl (meth) acrylate, (meth) acrylic acid 2- (Vinyloxyethoxyethoxy) isopropyl , 2- (vinyloxyethoxyisopropoxy) isopropyl (meth) acrylate, 2- (vinyloxyisopropoxyethoxy) isopropyl (meth) acrylate, 2- (vinyloxyisopropoxyisopropoxy) isopropyl (meth) acrylate 2- (vinyloxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxy) ethyl (meth) acrylate, ( 2- (isopropenoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxyethoxyethoxyethoxy) ethyl (meth) acrylate, (Meth) acrylic Examples include acid polyethylene glycol monovinyl ether and (meth) acrylic acid polypropylene glycol monovinyl ether.

  Among those exemplified above, since it is further excellent in curability, (meth) acrylic acid 2-vinyloxyethyl, (meth) acrylic acid 3-vinyloxypropyl, (meth) acrylic acid 1-methyl-2-vinyloxyethyl, (meth) acrylic 2-vinyloxypropyl acid, 4-vinyloxybutyl (meth) acrylate, 4-vinyloxycyclohexyl (meth) acrylate, 5-vinyloxypentyl (meth) acrylate, 6-vinyloxyhexyl (meth) acrylate, ( 4-vinyloxymethyl cyclohexylmethyl methacrylate), p-vinyloxymethyl phenylmethyl (meth) acrylate, 2- (vinyloxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxy) (meth) acrylate Ethoxy) ethyl, (meth) acrylic acid 2- (vinyloxyethoxy) Tokishietokishi) ethyl are preferred.

  Among these, because of low viscosity, high flash point, and excellent curability, 2- (vinyloxyethoxy) ethyl (meth) acrylate, that is, 2- (vinyloxyethoxy) ethyl acrylate and methacrylic acid At least one of 2- (vinyloxyethoxy) ethyl is preferable, and the former is more preferable. Examples of 2- (vinyloxyethoxy) ethyl (meth) acrylate include 2- (2-vinyloxyethoxy) ethyl (meth) acrylate and 2- (1-vinyloxyethoxy) ethyl (meth) acrylate. Examples of 2- (vinyloxyethoxy) ethyl acrylate include 2- (2-vinyloxyethoxy) ethyl acrylate and 2- (1-vinyloxyethoxy) ethyl acrylate.

  The polymerizable compound A may be used alone or in combination of two or more.

  The production method of the polymerizable compound A is not limited to the following, but is a method of esterifying (meth) acrylic acid and a hydroxyl group-containing vinyl ether (production method C), and a (meth) acrylic acid halide is converted to a hydroxyl group-containing vinyl ether. Esterification method (production method D), (meth) acrylic anhydride and hydroxyl group-containing vinyl ethers (ester E), (meth) acrylic acid esters and hydroxyl group-containing vinyl ethers are transesterified Method (Production Method F), Method of Esterification of (Meth) Acrylic Acid and Halogen-Containing Vinyl Ether (Production Method G), Method of Esterification of Alkali (Meth) acrylate (Earth) Metal Salt and Halogen-Containing Vinyl Ether (Production Method H), a method of vinyl-exchange of hydroxyl group-containing (meth) acrylic acid esters and vinyl carboxylate Process I), hydroxyl group-containing (meth) How to ether exchange and acrylic acid esters and alkyl vinyl ethers (process J) and the like.

（式（２）中、ｎは２〜６の整数を表す。） 1.1.2. Polymerizable compound B
The inkjet composition according to this embodiment contains a polymerizable compound B represented by the following general formula (2).

(In formula (2), n represents an integer of 2 to 6)

When the composition according to the present embodiment contains the polymerizable compound B represented by the general formula (2), the adhesion to various recording media can be improved. In addition, when used in combination with epoxy (meth) acrylate, epoxy (meth) acrylate has high sensitivity and reactivity, so that not only adhesion to various recording media is improved, but also curability and resistance. The rubbing property is further improved.

  Specific examples of the polymerizable compound B include N-vinylpyrrolidone and N-vinylcaprolactam.

  The content of the polymerizable compound B is preferably 1% by mass to 20% by mass, more preferably 3% by mass to 18% by mass, and particularly preferably 5% by mass with respect to the total mass (100% by mass) of the composition. It is not less than 15% by mass. When the content of the polymerizable compound B is within the above range, not only the adhesion of the composition to the recording medium is improved, but also the curability and the abrasion resistance are further improved. In addition, the storage stability of the radiation curable inkjet composition tends to be excellent.

1.1.3. Epoxy (meth) acrylate The composition according to the present embodiment contains epoxy (meth) acrylate. When the composition according to the present embodiment contains an epoxy (meth) acrylate, the adhesiveness to various recording media is excellent.

  When the composition according to the present embodiment contains only one of the polymerizable compound B and the epoxy (meth) acrylate, the adhesion to a specific type of recording medium is improved, but the compatibility with various recording media is improved. Is not expensive. Specifically, the adhesion to a vinyl chloride recording medium tends to be good, but the adhesion to a polyester recording medium and a PET recording medium tends not to improve so much. Therefore, by using the polymerizable compound B and the epoxy (meth) acrylate in combination, the adhesiveness to various recording media such as not only vinyl chloride recording media but also polyester recording media and PET recording media is improved. can do.

  However, when the polymerizable compound B and the epoxy (meth) acrylate are used in combination, the viscosity of the composition is likely to increase due to the influence of hydrogen bonding based on the hydroxyl group derived from the polymerizable compound B having a low melting point or the epoxy (meth) acrylate. . Therefore, when the polymerizable compound A represented by the general formula (1) is contained in an amount of 12% by mass or more, the composition has a low viscosity, and thus can be suitable for an ink jet recording method. Further, by containing 12% by mass or more of the polymerizable compound A, the reactivity of the epoxy (meth) acrylate is improved, so that not only adhesion to various recording media is improved, but also curability and abrasion resistance. Is further improved.

  The epoxy (meth) acrylate contained in the composition according to this embodiment can be synthesized from an unsaturated carboxylic acid and an epoxy compound. The synthesis method is not particularly limited, and a known synthesis method can be adopted. For example, it can synthesize | combine by mixing polymerization inhibitors, such as unsaturated carboxylic acid, an epoxy compound, a synthesis catalyst, and hydroquinone monomethyl ether, and making this mixture react at predetermined | prescribed temperature.

  Specific examples of the unsaturated carboxylic acid include mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and the like. One type selected from these That can be the end. In particular, at least one selected from the group consisting of acrylic acid and methacrylic acid is preferable.

As the synthesis catalyst, a known catalyst used in an esterification reaction between an acid group and an epoxy group can be used. However, from the viewpoint of a high reaction rate, tertiary amines, quaternary ammonium salts, and quaternary phosphonium salts are preferable as the synthesis catalyst. Examples of the tertiary amine include dimethylaminoethyl methacrylate. Examples of the quaternary ammonium salt include tetrabutylammonium chloride, tetraethylammonium bromide, tetrabutylammonium bromide, and tetrabutylammonium hydroxide. Examples of the quaternary phosphonium salt include tetraethylphosphonium bromide, tetrabutylphosphonium bromide, benzyltriphenylphosphonium chloride, and benzyltriphenylphosphonium bromide. These may be used alone or in combination of two or more.

  The epoxy compound is not particularly limited, but is preferably a compound having an aliphatic skeleton or an alicyclic skeleton. By using such an epoxy compound, the synthesized epoxy (meth) acrylate has an aliphatic skeleton or an alicyclic skeleton. By containing an epoxy (meth) acrylate having an aliphatic skeleton or an alicyclic skeleton, the hardness of the recorded image becomes appropriate. Note that the aliphatic skeleton and the alicyclic skeleton may have an unsaturated bond, or may have a heteroatom such as oxygen, nitrogen, sulfur, and chlorine bonded to a carbon chain. Moreover, although the said epoxy compound may contain an aromatic ring and a heterocyclic skeleton, not containing it is preferable at the point which reduces a viscosity and suppresses coloring.

  Examples of the epoxy compound having an aliphatic skeleton include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, lauryl alcohol glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol. Diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether Etc.

  Examples of the epoxy compound having an alicyclic skeleton include hydrogenated bisphenol A type, hydrogenated bisphenol F type epoxy compounds, alkylene oxide adducts thereof, cyclopentanediol diglycidyl ether, cyclopentane dimethanol diglycidyl ether, cyclohexane. Pentane diethanol diglycidyl ether, cyclohexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, cyclohexanediethanol diglycidyl ether, norbornanediol diglycidyl ether, norbornane dimethanol diglycidyl ether, norbornane diethanol diglycidyl ether, decalindiol diglycidyl ether, Decalin dimethanol diglycidyl ether, decalin diethanol jig Epoxy compounds of cycloaliphatic glycols such as sidyl ether 3,4-epoxycyclohexylmethylcarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-metadioxane, bis ( And alicyclic epoxy compounds such as 3,4-epoxycyclohexyl) adipate.

Specific examples of the epoxy (meth) acrylate include a reaction product of 1,6-hexanediol and (meth) acrylic acid (for example, trade name: Denacol DA-212, manufactured by Nagase ChemteX Corporation), propylene glycol di Reaction product of glycidyl ether and (meth) acrylic acid (for example, trade name: Denacol DA-911M, manufactured by Nagase ChemteX Corporation), reaction product of polyethylene glycol diglycidyl ether and (meth) acrylic acid (for example, Product names: Denacol DA-811, Denacol DM-811, Denacol DM-832, Denacol DM-851, manufactured by Nagase ChemteX Corporation), reaction product of polypropylene glycol diglycidyl ether and (meth) acrylic acid (for example, , Product name: Denacor DA-92 , Denacol DA-931, manufactured by Nagase ChemteX Corporation), reaction product of glycerol polyglycidyl ether and (meth) acrylic acid (for example, trade name: Denacol DA-314, manufactured by Nagase ChemteX Corporation), hydrogenated Reaction product of bisphenol A diglycidyl ether and (meth) acrylic acid (for example, trade name: Denacol DA-250, manufactured by Nagase ChemteX Corporation), epichlorohydrin-modified hydrogenated phthalic acid diacrylate (for example, trade name: Denacol) DA-722, manufactured by Nagase ChemteX Corporation).

  Among these, an epoxy (meth) acrylate having two (meth) acryloyl groups in one molecule is preferable. It is preferable that the number of (meth) acryloyl groups in one molecule is two because the crosslinking density in the recorded image (cured film) becomes appropriate and the hardness of the recorded image becomes appropriate. Moreover, the viscosity of the composition tends to be within a suitable range without becoming too high, which is preferable. When the number of (meth) acryloyl groups in one molecule is 3 or more, the crosslinking density in the cured film tends to be too high and too hard.

  The upper limit of the mass average molecular weight of the epoxy (meth) acrylate is preferably 2000 or less, more preferably 1500 or less, and particularly preferably 1000 or less. The lower limit of the mass average molecular weight of the epoxy (meth) acrylate is preferably 100 or more, more preferably 200 or more, and particularly preferably 300 or more. When the mass average molecular weight of the epoxy (meth) acrylate is within the above range, the increase in the viscosity of the composition can be reduced, so that it is suitable for an ink jet recording method.

  The unit viscosity of the epoxy (meth) acrylate at 25 ° C. is preferably 2000 mPa · s or less, more preferably 1500 mPa · s or less, and particularly preferably 1100 mPa · s or less. When the single viscosity of the epoxy (meth) acrylate is within the above range, the increase in the viscosity of the composition can be reduced, which is suitable for an ink jet recording method. The single-component viscosity of epoxy (meth) acrylate can be measured using a DVM-E type rotational viscometer (manufactured by Tokyo Keiki Co., Ltd.).

  The epoxy (meth) acrylate contained in the composition according to the present embodiment satisfies both the above-mentioned mass average molecular weight and unit viscosity at 25 ° C. from the viewpoint of reducing the viscosity of the composition. Particularly preferred. Further, from the viewpoint of lowering the viscosity of the composition, it is particularly preferable that there are two (meth) acryloyl groups in one molecule and the mass average molecular weight is in the above range.

  The content of the epoxy (meth) acrylate is preferably 1% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less, particularly preferably relative to the total mass (100% by mass) of the composition. It is 4 mass% or more and 12 mass% or less. When the content of the epoxy (meth) acrylate is within the above range, not only the adhesion to various recording media is improved, but also the curability and abrasion resistance are improved.

1.1.4. Other polymerizable compounds In the composition according to the present embodiment, various monomers and oligomers other than the above-described polymerizable compound, such as monofunctional, bifunctional, and trifunctional or more polyfunctional, can also be used.

  Although it does not specifically limit as a monofunctional monomer, The conventionally well-known monofunctional monomer which has a polymerizable functional group, especially the polymerizable functional group which has the unsaturated double bond between carbon can be used.

  Specific examples of the monofunctional monomer include, for example, unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, crotonic acid, isocrotonic acid and maleic acid; salts of the unsaturated carboxylic acid; esters of the unsaturated carboxylic acid , Urethanes, amides and anhydrides; acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, unsaturated urethanes; N- such as N-vinylformamide, N-vinylcarbazole and N-vinylacetamide A vinyl compound is mentioned. These monofunctional monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  Among these monofunctional monomers, from the viewpoint of improving the curability of the composition, monofunctional (meth) acrylic acid esters, that is, monofunctional (meth) acrylates are preferable.

  Monofunctional (meth) acrylates include isoamyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, isomyristyl (meth) acrylate, isostearyl (meth) ) Acrylate, 2-hydroxybutyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, lactone-modified flexible (meth) acrylate , T-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, (meth) acryloylmorpholine, cyclic trimethylolpropane formal (meth) acrylate, (2- Examples include methyl-2-ethyl-1,3-dioxolan-4-yl) methyl (meth) acrylate and 2- (meth) acrylic acid-1,4-dioxaspiro [4,5] dec-2-ylmethyl.

  Among the above monofunctional (meth) acrylates, it is also preferable to contain a monofunctional (meth) acrylate having an aromatic skeleton. When the monofunctional (meth) acrylate having an aromatic skeleton is contained, the solubility of the polymerization initiator described later tends to be good, and the curability tends to be improved, which is preferable. In particular, when an acylphosphine oxide polymerization initiator or a thioxanthone polymerization initiator is used, the solubility tends to be good. Among monofunctional (meth) acrylates having an aromatic skeleton, phenoxyethyl (meth) acrylate and benzyl (meth) acrylate are preferred, but phenoxyethyl (meth) acrylate is more preferred because of its lower odor.

  The content of the monofunctional (meth) acrylate having an aromatic skeleton is preferably 20% by mass or more and 50% by mass or less, more preferably 22% by mass or more and 40% by mass with respect to the total mass (100% by mass) of the composition. % Or less, particularly preferably 25% by mass or more and 38% by mass or less. When the content of the monofunctional (meth) acrylate having an aromatic skeleton is within the above range, the solubility of the polymerization initiator tends to be good, and the curability is further improved. In particular, when an acylphosphine oxide polymerization initiator or a thioxanthone polymerization initiator is used, the solubility tends to be good.

  The content of the monofunctional monomer is preferably 50% by mass or less, more preferably 1% by mass with respect to the total mass (100% by mass) of the composition from the viewpoint of improving the curability of the composition. % To 45% by mass, particularly preferably 5% to 40% by mass.

Although it does not specifically limit as a bifunctional monomer, For example, bifunctional (meth) acrylate can be used, As the specific example, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol diester (Meta)
Acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, bisphenol A EO (ethylene oxide) Adduct di (meth) acrylate, PO (propylene oxide) adduct di (meth) acrylate of bisphenol A, neopentyl glycol di (meth) acrylate hydroxypivalate, and poly Tiger glycol di (meth) acrylate.

  Although it does not specifically limit as a polyfunctional monomer more than trifunctional, For example, a polyfunctional (meth) acrylate more than trifunctional can be used, As a specific example, a trimethylol propane tri (meth) acrylate, EO modified | denatured tri Methylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerin propoxytri (meth) acrylate, Caprolactone-modified trimethylolpropane tri (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, and caprolactam-modified dipentaerythritol hexa (meth) acrylate Relate and the like.

  The content of the bifunctional or higher polyfunctional monomer is preferably 0.5% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass or less, based on the total mass (100% by mass) of the composition. Particularly preferably, the content is 2% by mass or more and 8% by mass or less. By setting it as the said preferable range, it exists in the tendency which is excellent with sclerosis | hardenability, storage stability, and discharge stability.

  The composition according to the present embodiment is a non-aqueous composition containing the largest amount of the above-described polymerizable compound among medium components in which a solid content such as a polymerization initiator or a coloring material is dissolved or dispersed. From the viewpoint of stability and storage stability. The medium component having the largest mass ratio among the medium components contained in the composition is a polymerizable compound. The content of the polymerizable compound is preferably 40% by mass to 95% by mass, more preferably 50% by mass or more, still more preferably 60% by mass or more, based on the total mass (100% by mass) of the composition. More preferably, it is less than 80% by weight, and more preferably less than 80% by weight. When the content of the polymerizable compound is within the above range, the viscosity can be further reduced, and the solubility and reactivity of the polymerization initiator can be further improved.

1.2. Polymerization initiator The composition according to this embodiment preferably contains a polymerization initiator. Although it does not specifically limit as a polymerization initiator, For example, well-known polymerization initiators, such as an alkylphenone type polymerization initiator, an acyl phosphine oxide type polymerization initiator, a titanocene type polymerization initiator, a thioxanthone polymerization initiator, are mentioned. Of these, acylphosphine oxide polymerization initiators are preferred. By containing an acyl phosphine oxide-based polymerization initiator, the curability of the composition is excellent, and in particular, the curability by the curing process by UV-LED tends to be further excellent.

  Examples of the acylphosphine oxide polymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and bis- (2,6-dimethoxy). And benzoyl) -2,4,4-trimethylpentylphosphine oxide.

Examples of commercially available acylphosphine oxide polymerization initiators include IRGACU.
RE 819 (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide), IRGACURE 1800 (bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and 1-hydroxy- And a mixture of cyclohexyl-phenyl ketone having a mass ratio of 25:75), IRGACURE TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide) (all manufactured by BASF) and the like.

  A polymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more type. In particular, by using a combination of an acyl phosphine oxide polymerization initiator and a thioxanthone polymerization initiator, not only can the composition have excellent curability, but also prevent coloring of the initial cured film after inkjet recording. You can also. Thus, the polymerization initiator preferably contains an acyl phosphine oxide polymerization initiator, and more preferably contains an acyl phosphine oxide polymerization initiator and a thioxanthone polymerization initiator.

  Among the thioxanthone polymerization initiators, 2,4-diethylthioxanthone is preferable because of its excellent sensitizing effect on acylphosphine oxide, solubility in polymerizable compounds, and safety.

  Examples of commercially available thioxanthone polymerization initiators include KAYACURE DETX-S (2,4-diethylthioxanthone) (trade name, manufactured by Nippon Kayaku Co., Ltd.) ITX (manufactured by BASF), Quanture CTX (manufactured by Aceto Chemical) ).

  The content of the polymerization initiator is preferably 1% by mass or more and 20% by mass or less, more preferably 15% by mass or less, in terms of further excellent curability and discharge stability with respect to the total mass (100% by mass) of the composition. More preferably, it is more preferably 13% by mass or less, and particularly preferably 10% by mass or less. Moreover, 3 mass% or more is further more preferable, and 5 mass% or more is especially preferable.

1.3. Other Additives The composition according to this embodiment may further contain additives such as a coloring material, a dispersant, a polymerization inhibitor, a surfactant, a sensitizer, and a polymerization inhibitor, as necessary.

<Color material>
The composition according to this embodiment may further include a color material. When the composition according to the present embodiment includes a coloring material, it can be used as a colored ink composition. As the color material, at least one of a pigment and a dye can be used.

(Pigment)
By using a pigment as the color material, the light resistance of the ink composition can be improved. As the pigment, both inorganic pigments and organic pigments can be used.

  As the inorganic pigment, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, iron oxide, and titanium oxide can be used.

Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc. Polycyclic pigments, dye chelates (eg basic dye chelates, acid dye chelates, etc.), dye rakes (basic dye rakes, acid dye rakes), nitro pigments, nitroso pigments, aniline black, daylight A fluorescent pigment is mentioned.

More specifically, as a carbon black used for black ink, No. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B, etc. (Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (above, Columbia Carbon, Carbon 1 Rubbi 400, Carbon Co. Rega1 330R, Rega1 660R, Mogul L, Monarch 700, Monarch 800, Monarch
880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (manufactured by Cabot Corporation (CABOT JAPAN K.K.)), Color Black FW1, Color Black FW2, Color Black VLC, Color Black FW2, Color Black FW , Color B1ack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6, Speck Black, A Etsu Chemical Co., Ltd.) and the like.

  Examples of pigments used in white ink include C.I. I. Pigment white 6, 18, and 21.

  Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, or C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50.

  Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15:34, 15: 4, 16, 18, 22, 25, 60, 65, 66, C.I. I. Bat Blue 4, 60.

  Examples of pigments other than magenta, cyan, and yellow include C.I. I. Pigment green 7, 10, C.I. I. Pigment brown 3, 5, 25, 26, C.I. I. Pigment orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, 63.

  The said pigment may be used individually by 1 type, and may use 2 or more types together.

  When using said pigment, the average particle diameter has preferable 300 nm or less, and 50-200 nm is more preferable. When the average particle diameter is in the above range, the ink composition is more excellent in reliability such as ejection stability and dispersion stability, and an image with excellent image quality can be formed. Here, the average particle diameter in the present specification is measured by a dynamic light scattering method.

(dye)
A dye can be used as the coloring material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive black 3, 4, and 35 are mentioned.

  The said dye may be used individually by 1 type, and may use 2 or more types together.

  The content of the color material is preferably 1% by mass or more and 20% by mass or less with respect to the total mass (100% by mass) of the ink composition. It is good also as a clear composition (clear ink) which does not contain a coloring material or contains a coloring material to such an extent that it does not aim at coloring (for example, 0.1 mass% or less).

<Dispersant>
When the ink composition contains a pigment, it may further contain a dispersant in order to improve pigment dispersibility. Although it does not specifically limit as a dispersing agent, For example, the dispersing agent currently used in preparing pigment dispersion liquids, such as a polymer dispersing agent, is mentioned. Specific examples include polyoxyalkylene polyalkylene polyamines, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, sulfur-containing polymers, fluorine-containing polymers, and epoxies. The thing which has 1 or more types of resin as a main component is mentioned. Commercially available polymer dispersants include Ajinomoto Fine-Techno's Adisper Series, Avecia and Noveon Solsperse Series (Solsperse 36000, etc.), BYK Additives & Instruments Dispervic Series , Disparon series manufactured by Enomoto Kasei.

<Polymerization inhibitor>
The composition according to this embodiment may further contain a hindered amine compound or other substances as a polymerization inhibitor. Examples of other polymerization inhibitors include, but are not limited to, p-methoxyphenol, hydroquinone monomethyl ether (MEHQ), phenothiazine, hydroquinone, cresol, t-butylcatechol, 3,5-di-t-butyl-4- Hydroxytoluene, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-butylphenol), and 4,4′-thiobis (3-methyl-6) -T-butylphenol). A polymerization inhibitor may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the polymerization inhibitor is preferably 0.0 with respect to the total mass (100% by mass) of the composition.
It is 5 mass% or more and 0.5 mass%, More preferably, it is 0.1 mass% or more and 0.5 mass% or less.

<Surfactant>
The composition according to this embodiment may further contain a surfactant. As the surfactant, a silicone-based surfactant is preferable, and polyester-modified silicone or polyether-modified silicone is more preferable. Examples of the polyester-modified silicone include BYK-347, 348, BYK-UV3500, 3510, 3530 (manufactured by BYK Additives & Instruments) and the like, and examples of the polyether-modified silicone include BYK-3570 (manufactured by BYK Additives & Instruments). Can be mentioned. Surfactant may be used individually by 1 type and may be used in combination of 2 or more type.

  The content of the surfactant is preferably 0.01% by mass to 2% by mass, and more preferably 0.05% by mass to 1% by mass with respect to the total mass (100% by mass) of the composition.

<Sensitizer>
The composition according to this embodiment may further contain a sensitizer. Sensitizers include amine compounds (aliphatic amines, amines containing aromatic groups, piperidine, reaction products of epoxy resins and amines, triethanolamine triacrylate, etc.), urea compounds (allylthiourea, o-tolylthiourea, etc.) ), Sulfur compounds (sodium diethyldithiophosphate, soluble salts of aromatic sulfinic acid, etc.), nitrile compounds (N, N-diethyl-p-aminobenzonitrile, etc.), phosphorus compounds (tri-n-butylphosphine, sodium) Diethyldithiophosphide), nitrogen compounds (Michler ketone, N-nitrisohydroxylamine derivatives, oxazolidine compounds, tetrahydro-1,3-oxazine compounds, formaldehyde or acetaldehyde and diamine condensates), chlorine compounds (carbon tetrachloride) , Hexachloroethane, etc.), and the like.

1.4. Physical Properties The viscosity at 20 ° C. of the composition according to this embodiment is preferably 25 mPa · s or less, and more preferably 5 to 20 mPa · s. When the viscosity of the composition at 20 ° C. is in the above range, the composition can be discharged from the nozzle in an appropriate amount, and the flight bending and scattering of the composition can be further reduced. Therefore, the composition can be suitably used for an ink jet recording apparatus. . The viscosity is measured by using a viscoelasticity tester MCR-300 (manufactured by Pysica), increasing the Shear Rate to 10 to 1000 in an environment of 20 ° C., and reading the viscosity at Shear Rate 200. Can be measured.

  The surface tension at 20 ° C. of the composition according to this embodiment is preferably 20 mN / m or more and 30 mN / m or less. When the surface tension of the composition at 20 ° C. is in the above range, the composition is less likely to get wet with the nozzle subjected to the liquid repellent treatment. Accordingly, an appropriate amount of the composition is ejected from the nozzle, and the flight bending and scattering of the composition can be further reduced. Therefore, the composition can be suitably used for an ink jet recording apparatus. The surface tension is measured by using an automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) by confirming the surface tension when the platinum plate is wetted with ink in an environment of 20 ° C. be able to.

1.5. Method for Producing Composition The composition can be produced (prepared) by mixing the components contained in the composition and stirring the components so that they are sufficiently uniformly mixed. In this embodiment, the preparation of the composition is a step of performing at least one of ultrasonic treatment and heating treatment on a mixture obtained by mixing a polymerization initiator and at least a part of the polymerizable compound in the course of preparation. It is preferable to have. Thereby, the dissolved oxygen amount of the composition after preparation can be reduced, and it can be set as the composition excellent in discharge stability and storage stability. The said mixture should just contain said component at least, and may further contain the other component contained in a composition, and may contain all the components contained in a composition. The polymerizable compound included in the mixture may be at least part of the polymerizable compound included in the composition.

2. Recording Method The recording method according to this embodiment is characterized in that recording is performed on a recording medium using the above-mentioned radiation curable inkjet composition. In this way, a cured film is formed at the location where the composition is applied on the recording medium. According to the recording method according to the present embodiment, since the composition has a low viscosity, it is possible to realize good recording of the ink jet system. Further, it is possible to record an image having excellent adhesion to various recording media and excellent curability and abrasion resistance. Hereinafter, detailed steps in the recording method according to the present embodiment will be described.

<Application process>
In the step of applying the composition onto the recording medium, a known ink jet recording apparatus can be used. When discharging the composition, as described above, the viscosity of the composition at 20 ° C. is preferably 25 mPa · s or less, and more preferably 5 to 20 mPa · s. If the viscosity of the composition is within the above range, the composition can be discharged at room temperature or without heating the composition. On the other hand, the viscosity may be preferably discharged by heating the composition to a predetermined temperature. In this way, good discharge stability is realized.

  A radiation curable inkjet composition generally has a higher viscosity than a water-based ink composition used for inkjet applications, and therefore has a large viscosity variation due to temperature variation during ejection. Viscosity fluctuation of such a composition has a great influence on the change of the droplet size and the change of the droplet discharge speed, and can cause image quality deterioration. Therefore, it is preferable to keep the temperature of the composition during ejection as constant as possible.

  By using the above-mentioned radiation curable inkjet composition, it is possible to record an image having excellent adhesion to various recording media. Therefore, the recording medium is not particularly limited, but preferably contains any one of vinyl chloride (polyvinyl chloride), polyester (polyethylene terephthalate), polycarbonate, and polyolefin (polypropylene, polyethylene). .

<Curing process>
Next, in the curing step, the composition applied on the recording medium is cured by irradiation with UV-LED. In other words, the coating film of the composition formed on the recording medium becomes a cured film by UV-LED irradiation. This is because the polymerization initiator that can be contained in the composition is decomposed by irradiation of ultraviolet rays to generate starting species such as radicals, acids, and bases, and the polymerization reaction of the polymerizable compound is accelerated by the function of the starting species. It is to be done. Or it is because the photopolymerization reaction of a polymeric compound starts by irradiation of an ultraviolet-ray. At this time, if a sensitizing dye is present together with the polymerization initiator in the 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 photopolymerization initiator. And a more sensitive curing reaction can be achieved.

Further, by using a UV-LED as an ultraviolet ray source, it is possible to reduce the size of the apparatus and reduce the cost. Since the UV-LED as the ultraviolet ray source is small, it can be mounted in the ink jet recording apparatus. For example, it can be attached to a carriage (both ends along the medium width direction and / or the medium conveyance direction side) on which a print head for discharging the composition is mounted. Furthermore, low energy and high speed curing can be realized due to the composition of the composition described above. The irradiation energy is calculated by multiplying the irradiation time by the irradiation intensity. Therefore, the irradiation time can be shortened and the printing speed is increased. On the other hand, the irradiation intensity can also be reduced. Thereby, since the temperature rise of printed matter can be reduced, it leads also to the low odor of a cured film.

The irradiation energy, from the viewpoint of reducing the odor of the cured film is preferably 50~1000mJ / cm ^2, more preferably ^{100~700mJ / cm 2, 200~600mJ / cm} 2 is particularly preferred.

The irradiation intensity, from the viewpoint of reducing the odor of the cured film is preferably 10 to 1,000 / cm ^2, more preferably ^{30~700mW / cm 2, 50~500mW / cm} 2 is particularly preferred.

3. Examples Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples.

3.1. Preparation of composition First, a part of the pigment (CI Pigment Blue 15: 3) and the polymerizable compound (PEA) is weighed and placed in a pigment dispersion tank, and a ceramic bead mill having a diameter of 1 mm is placed in the tank. To obtain a 30% pigment dispersion in which the pigment is dispersed in the polymerizable compound. Then, the remaining polymerizable compound, polymerization initiator, polymerization inhibitor and surfactant are put into a tank for the mixture which is a stainless steel container so as to have the composition described in Tables 1 to 3, and mixed and stirred. After complete dissolution, the pigment dispersion obtained above was added, mixed and stirred at room temperature for 1 hour, and further filtered through a 5 μm membrane filter to obtain each composition.

The components used in the table are as follows.
<Polymerizable compound>
(Polymerizable compound A)
VEEA (trade name, manufactured by Nippon Shokubai Co., Ltd., 2- (2-vinyloxyethoxy) ethyl acrylate)
(Polymerizable compound B)
・ N-VC (manufactured by BASF, N-vinylcaprolactam)
(Epoxy (meth) acrylate)
DA-212 (trade name, manufactured by Nagase ChemteX Corporation, reaction product of 1 molecule of 1,6-hexanediol diglycidyl ether and 2 molecules of (meth) acrylic acid)
DA-911M (trade name, manufactured by Nagase ChemteX Corporation, reaction product of 1 molecule of propylene glycol diglycidyl ether and 2 molecules of (meth) acrylic acid)
DA-920 (trade name, manufactured by Nagase ChemteX Corporation, reaction product of 1 molecule of polypropylene glycol diglycidyl ether and 2 molecules of (meth) acrylic acid)
DA-931 (trade name, manufactured by Nagase ChemteX Corporation, reaction product of one molecule of polypropylene glycol diglycidyl ether and two molecules of (meth) acrylic acid)
DA-314 (trade name, manufactured by Nagase ChemteX Corporation, reaction product of 1 molecule of glycerol polyglycidyl ether and 3 molecules of (meth) acrylic acid)
DA-722 (trade name, manufactured by Nagase ChemteX Corporation, epichlorohydrin-modified hydrogenated phthalic acid diacrylate)
DA-250 (trade name, manufactured by Nagase ChemteX Corporation, reaction product of 1 molecule of hydrogenated bisphenol A diglycidyl ether and 2 molecules of (meth) acrylic acid)
DA-141 (trade name, manufactured by Nagase ChemteX Corporation, phenolic epoxy acrylate)
・ EBECRYL3708 (trade name, manufactured by Daicel Ornex Co., Ltd., modified epoxy acrylate)
(Other polymerizable compounds)
-PEA (trade name “Biscoat # 192”, manufactured by Osaka Organic Chemical Industry Co., Ltd., phenoxyethyl acrylate)
・ IBXA (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., isobornyl acrylate)
<Polymerization initiator>
・ TPO (trade name “IRGACURE TPO”, manufactured by BASF, 2,4,6-trimethylbenzoyldiphenylphosphine oxide)
IRGACURE 819 (trade name, manufactured by BASF, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide)
DETX (trade name “KAYACURE DETX-S”, Nippon Kayaku Co., Ltd., 2,4-diethylthioxanthone)
<Polymerization inhibitor>
MEHQ (trade name “p-methoxyphenol”, manufactured by Kanto Chemical Co., Inc., hydroquinone monomethyl ether)
・ Phenothiazine (Kanto Chemical Co., Ltd.)
<Surfactant>
BYK-UV3500 (trade name, manufactured by BYK Additives & Instruments, polyether-modified polydimethylsiloxane having an acrylic group)
<Pigment>
・ Cyan pigment (CI Pigment Blue 15: 3)

3.2. Evaluation method About the radiation-curable inkjet composition prepared in each Example and Comparative Example, the curability, adhesion, viscosity, and abrasion resistance were evaluated by the following methods.

<Curing property>
Using the inkjet printer PX-G5000 (trade name, manufactured by Seiko Epson Corporation), each of the nozzle arrays was filled with the radiation curable inkjet composition. A solid pattern image was printed on a vinyl chloride sheet (Viewcal 2000 (white), manufactured by Sakurai Co., Ltd.) at normal temperature and normal pressure under the conditions of a recording resolution of 720 dpi × 720 dpi and a droplet weight of 7 ng. Note that this solid pattern image is an image in which dots are recorded for all of the pixels that are the minimum recording unit area defined by the recording resolution. Along with the above printing, a solid pattern image was cured by irradiating UV light having an irradiation intensity of 400 mW / cm ² and a wavelength of 395 nm from a UV-LED in an ultraviolet irradiation device mounted on the side of the carriage. In addition, it was judged that it was hardened | cured when the tackiness of the image (coating film surface) disappeared by the finger touch test.

Evaluation was performed by calculating the irradiation energy of ultraviolet rays required for curing. The irradiation energy [mJ / cm ² ] was determined from the product of the irradiation intensity [mW / cm ² ] on the irradiated surface irradiated from the light source and the irradiation duration [s]. The irradiation intensity was measured using an ultraviolet intensity meter UM-10 and a light receiving unit UM-400 (both manufactured by KONICA MINOLTA SENSING, INC.). The evaluation criteria are as follows. ○ and Δ are practically acceptable evaluation criteria. The evaluation results are shown in Tables 1 to 3.
(Evaluation criteria)
○: Less than 300 mJ / cm ² Δ: 300 mJ / cm ² or more and less than 500 mJ / cm ² ×: 500 mJ / cm ² or more

<Adhesion>
Using the inkjet printer PX-G5000 (trade name, manufactured by Seiko Epson Corporation), each of the nozzle arrays was filled with the radiation curable inkjet composition. Irradiation with ultraviolet rays mounted on the side of the carriage against the composition deposited on the medium, ejected with an ink drop amount of 10 μm (cured film) on one of the following media at room temperature and normal pressure UV rays having an irradiation intensity of 400 mW / cm ² and a wavelength of 395 nm were irradiated from the UV-LED in the apparatus to be completely cured.

In order to evaluate adhesion, first, as a cutting tool, a single blade cutting tool (generally available cutter) and a guide for cutting at equal intervals using a single blade cutting tool were prepared. First, the blade of the cutting tool was applied so as to be perpendicular to the obtained cured film, and six cuts (distance between the cuts: 1 mm, the same applies hereinafter) were made in the cured film. After making these six cuts, the direction of 90 ° was changed, and another six cuts were made so as to be orthogonal to the cuts already made. Next, a transparent adhesive tape (width: 25 ± 1 mm) with a length of about 75 mm is applied to the part of the cured film cut in a lattice shape, and the tape is rubbed with fingers enough to see through the cured film. It was. Next, within 5 minutes after applying the tape, the tape was reliably peeled off from the cured film in an angle close to 60 ° in 0.5 to 1.0 seconds, and the state of the cured film was visually observed. . The evaluation criteria are as follows. ○ and Δ are practically acceptable evaluation criteria. The evaluation results are shown in Tables 1 to 3.
(Media type)
・ Media A: Vinyl chloride sheet (trade name “Viewcal2000 (white)”, manufactured by Sakurai Co., Ltd.)
・ Media B: Polycarbonate film (trade name “Iupilon FE-2000”, manufactured by Mitsubishi Engineering Plastics)
Media C: PET film (trade name “PET50A PL Thin”, manufactured by Lintec Corporation)
(Evaluation criteria)
(Double-circle): Peeling of the cured film was not recognized.
○: Separation of the cured film was observed in more than 0% and 5% or less of the lattice.
Δ: Exfoliation of the cured film was observed in more than 5% and not more than 35% of the lattice.
X: Exfoliation of the cured film was observed in more than 35% of the lattice.

<Viscosity>
Using a DVM-E rotational viscometer (manufactured by Tokyo Keiki Co., Ltd.), the viscosity at 20 ° C. of each composition prepared above was measured. As the rotor, a DVM-E type cone having a cone angle of 1 ° 34 ′ and a cone radius of 2.4 cm was used. The rotation speed was 10 rpm. The evaluation criteria are as follows. ○ and Δ are practically acceptable evaluation criteria. The evaluation results are shown in Tables 1 to 3. (Evaluation criteria)
○: Less than 15 mPa · s Δ: 15 mPa · s or more and less than 25 mPa · s ×: 25 mPa · s or more

<Abrasion resistance>
Printing and curing of a solid pattern image similar to the above evaluation items of curability were performed on the vinyl chloride sheet (Viewcal 2000 (white), manufactured by Sakurai Co., Ltd.). And the peeling degree of the cured film (coating film) was confirmed using the load fluctuation type frictional wear test system (Brand name "Tribogear TYPE-HHS2000", Shinto Kagaku Co., Ltd. product). Conditions were such that the load was set to 150 gf, the solid pattern image after curing was scratched with a sapphire needle of φ0.2 mm, and the degree to which the coating film was peeled off was confirmed. The evaluation criteria are as follows. ○ and Δ are practically acceptable evaluation criteria. The evaluation results are shown in Tables 1 to 3.
(Evaluation criteria)
○: There is no scratch or peeling on the coating surface.
Δ: The coating film surface is scratched. There is no peeling.
X: The coating surface is scratched and the coating is peeled off.

3.3. Evaluation results Tables 1 to 3 below show the compositions of the compositions used in Examples and Comparative Examples, and the evaluation results. In addition, the numerical value of each component shown in each Example and each comparative example in a table | surface represents the mass%.

From the evaluation results of Tables 1 to 3, the compositions of Examples 1 to 25 according to the present invention have a low viscosity composition and can sufficiently correspond to an ink jet recording method. It was confirmed that the adhesiveness to various recording media and the abrasion resistance of recorded images were excellent. In addition, the composition of Example 12 had a viscosity increase with time compared with the composition of Example 11, and was inferior in storage stability.

  The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

Claims (10)

Polymerizable compound A represented by the following general formula (1);
Polymerizable compound B represented by the following general formula (2);
Epoxy (meth) acrylate,
A radiation curable inkjet composition containing
A radiation curable inkjet composition containing 12% by mass or more of the polymerizable compound A.
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (1)
(In the formula (1), ^{R 1} is a hydrogen atom or a methyl group, ^{R 2} is a divalent organic residue having 2 to 20 carbon atoms, ^{R 3} is a monovalent hydrogen atom or a C 1 to 11 This is an organic residue.)

(In formula (2), n represents an integer of 2 to 6)   The radiation curable inkjet composition according to claim 1, wherein the content of the polymerizable compound A is 40% by mass or less.   The radiation curable inkjet composition according to claim 1 or 2, wherein the content of the polymerizable compound B is 5% by mass or more and 15% by mass or less.   The radiation curable inkjet composition according to any one of claims 1 to 3, wherein the content of the epoxy (meth) acrylate is 3% by mass or more and 15% by mass or less.   The radiation curable inkjet composition according to any one of claims 1 to 4, further comprising 20% by mass or more and 50% by mass or less of a monofunctional (meth) acrylate having an aromatic skeleton.   The radiation curable inkjet composition according to any one of claims 1 to 5, wherein the epoxy (meth) acrylate has two (meth) acryloyl groups in one molecule.   The radiation curable inkjet composition according to any one of claims 1 to 6, wherein the epoxy (meth) acrylate has an aliphatic skeleton or an alicyclic skeleton.   The radiation-curable inkjet according to any one of claims 1 to 7, wherein the epoxy (meth) acrylate has a mass average molecular weight of 2000 or less and a single-body viscosity of 2000 mPa · s or less at 25 ° C. Composition.   A recording method for recording on a recording medium using the radiation curable inkjet composition according to claim 1.   The recording method according to claim 9, wherein the recording medium includes any one of vinyl chloride, polyester, polycarbonate, and polyolefin resins.