JP2017197647A - Radiation-curable inkjet composition and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-curable inkjet composition having reduced odor and showing good curability.SOLUTION: The radiation-curable inkjet composition comprises a monomer A represented by general formula (I) CH=CR-COOR-O-CH=CH-R, a monomer B described below, and a monomer C that is a monofunctional (meth)acrylate having an aromatic ring skeleton. In formula (I), 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. The monomer B has one (meth)acryloyloxy group or (meth)acryloyl group, in which a total number of nitrogen atoms and oxygen atoms except for oxygen atoms included in the above (meth)acryloyloxy group and (meth)acryloyl group is 2 or more, and has a cyclic, linear or branched chain structure. The composition contains the monomer B by 15 mass% or more with respect to the total mass.SELECTED DRAWING: None

Description

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

  In recent years, in order to form images with high water resistance, solvent resistance, scratch resistance, etc. on the surface of a recording medium, a radiation curable ink composition that cures when irradiated with radiation in an ink jet recording method has been used. Has been.

  For example, in the technique described in Patent Document 1, by using an ink composition containing a plurality of types of monomers including a polyfunctional acrylate monomer, the curability, extensibility, and wrinkle of an image formed on a recording medium are used. We are trying to reduce it.

JP 2013-060548 A

  However, the radiation curable inkjet composition is composed of a polymerizable compound such as a monofunctional monomer or a polyfunctional monomer, or an organic material such as a photopolymerization initiator. For this reason, in the radiation curable inkjet composition, reducing the odor of the composition itself is one of the important issues.

  The ink composition disclosed in Patent Document 1 contains 2- (2-vinyloxyethoxy) ethyl acrylate as a kind of monomer. Therefore, although sclerosis | hardenability became favorable, the odor was strong.

  According to investigations by the inventors, it has been found that there is a possibility of reducing the odor by adding a certain amount of a specific monomer or more. However, the specific monomer is similar to acrylamides such as N-acryloylmorpholine and is considered to have a molecular structure, but the ability to dissolve the polymerization initiator tends to be insufficient. When the solubility of the polymerization initiator is insufficient, the curability of the composition becomes insufficient. Accordingly, it has been found that reducing the odor by increasing the amount of the monomer added and maintaining good curability are in a trade-off relationship.

  One of the objects according to some embodiments of the present invention is to provide a radiation curable ink jet composition having reduced odor and good curability, and an ink jet recording method.

  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.

One aspect of the radiation curable inkjet composition according to the present invention is:
Monomer A represented by the following general formula (I):
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
(In Formula (I), R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent having 1 to 11 carbon atoms. This is an organic residue.)
One (meth) acryloyloxy group or one (meth) acryloyl group, the number of nitrogen atoms, and the number of oxygen atoms other than oxygen atoms contained in the (meth) acryloyloxy group and the (meth) acryloyl group A monomer B having a cyclic, linear or branched structure, the total of which is 2 or more;
Monomer C which is a monofunctional (meth) acrylate having an aromatic ring skeleton,
Containing
The monomer B is contained in a total of 15% by mass or more with respect to the total mass.

  According to such a radiation curable inkjet composition, the odor can be reduced by containing 15% by mass or more of the monomer B. Moreover, by containing the monomer C, a polymerization initiator can fully be dissolved and favorable curability can be obtained.

In the radiation curable inkjet composition according to the present invention,
The monomer B may be contained in a total amount of 15% by mass to 49% by mass with respect to the total mass.

  Such a radiation curable inkjet composition is sufficiently suppressed in odor.

In the radiation curable inkjet composition according to the present invention,
The monomer C is a compound represented by the following general formula (II), and
_{^{CH 2 = CR 4 -COOR 5 -Ar}} ··· (II)
Following compound represented by general formula ^{_{(III) CH 2 = CR 4}} -COO-Ar ··· (III)
May be at least one of the following.

(In the above formulas (II) and (III), R ⁴ is a hydrogen atom or a methyl group. In the above formula (II), Ar representing an aromatic ring skeleton has at least an aryl group and constitutes the aryl group. In which the carbon atom to be bonded is a monovalent organic residue bonded to the group represented by R ⁵ , and R ⁵ is a divalent organic residue having 1 to 4 carbon atoms. Ar representing an aromatic ring skeleton is a monovalent organic residue having at least an aryl group, and a carbon atom constituting the aryl group bonded to —COO— in the formula.
According to such a radiation curable inkjet composition, the molecular structure of the monomer C is more easily compatible with the molecule of the polymerization initiator, so that the polymerization initiator can be dissolved more satisfactorily. Thereby, sclerosis | hardenability is further favorable.

In the radiation curable inkjet composition according to the present invention,
An acyl phosphine oxide photopolymerization initiator may be contained.

  According to such a radiation curable inkjet composition, the polymerization initiator has higher affinity with the monomer C, which is a monofunctional (meth) acrylate having an aromatic ring skeleton, and the polymerization initiator can be dissolved more satisfactorily. The curability is even better.

In the radiation curable inkjet composition according to the present invention,
The acylphosphine oxide photopolymerization initiator may be contained in a total amount of 1% by mass to 10% by mass with respect to the total mass.

  According to such a radiation curable ink jet composition, the polymerization initiator can be sufficiently dissolved and sufficient active species can be generated. This further improves the curability.

In the radiation curable inkjet composition according to the present invention,
The monomer B may be a compound having a cyclic skeleton.

  According to such a radiation curable inkjet composition, odor can be further reduced.

In the radiation curable inkjet composition according to the present invention,
The monomer A may be contained in a total amount of 10% by mass to 30% by mass with respect to the total mass.

  According to such a radiation curable inkjet composition, the curability is further improved, and the odor can be further suppressed by the action of the monomer B contained in a total amount of 15% by mass or more with respect to the total mass.

In the radiation curable inkjet composition according to the present invention,
The monomer C may be contained in a total amount of 10% by mass to 30% by mass with respect to the total mass.

  According to such a radiation curable inkjet composition, the polymerization initiator can be dissolved more satisfactorily. Thereby, sclerosis | hardenability is further favorable.

In the radiation curable inkjet composition according to the present invention,
The monomer A may be a compound having a glycol ether chain.

  Such a radiation curable ink jet composition can have a lower viscosity and is excellent in curability.

In the radiation curable inkjet composition according to the present invention,
The monomer B may be an acrylamide.

  According to such a radiation curable inkjet composition, odor can be further reduced.

In the radiation curable inkjet composition according to the present invention,
30 mass% or less may be sufficient as content of the total of polyfunctional (meth) acrylate.

  In such a radiation curable inkjet composition, the total content of the polyfunctional (meth) acrylate is 30% by mass or less with respect to the total mass of the inkjet composition. can do.

One aspect of the inkjet recording method according to the present invention is:
Attaching the radiation curable inkjet composition described above to a recording medium;
Irradiating the radiation-curable inkjet composition with UV-LED light.

In the inkjet recording method according to the present invention,
The irradiation energy of the UV-LED may be 50 to 1000 mJ / cm ² .

In the inkjet recording method according to the present invention,
The irradiation intensity of the UV-LED may be 10 to 1000 mW / cm ² .

In the inkjet recording method according to the present invention,
The temperature of the recording medium in the step of attaching to the recording medium may be less than 45 ° C.

  According to such an ink jet recording method, odor can be reduced and an excellent curable image can be recorded.

  Several embodiments of the present invention will be described below. Embodiment described below demonstrates an example of this invention. The present invention is not limited to the following embodiments, and includes various modified embodiments that are implemented within a range that does not change the gist of the present invention. Note that not all of the configurations described below are essential configurations of the present invention.

  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.

1. Radiation curable inkjet composition The radiation curable inkjet composition according to this 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, the radiation curable inkjet ink composition will be described as an 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. . In addition, as an embodiment of the “radiation curable type”, there are cases where it is described as “ultraviolet curable type”, “photo curable type”, etc., but in this embodiment, the composition is used by being cured by irradiation with radiation. Any curable composition may be used, and 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.

The radiation curable inkjet composition according to this embodiment includes a monomer A represented by the following general formula (I):
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
(In Formula (I), R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent having 1 to 11 carbon atoms. This is an organic residue.)
One (meth) acryloyloxy group or one (meth) acryloyl group, the number of nitrogen atoms, and the number of oxygen atoms other than oxygen atoms contained in the (meth) acryloyloxy group and the (meth) acryloyl group A monomer B having a cyclic, linear or branched structure, the total of which is 2 or more;
Monomer C which is a monofunctional (meth) acrylate having an aromatic ring skeleton,
Containing
The monomer B is contained in a total of 15% by mass or more with respect to the total mass.

  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. Monomer A
The radiation curable inkjet composition of this embodiment contains monomer A (vinyl ether group-containing (meth) acrylate) represented by the following general formula (I).

_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
(In Formula (I), R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent having 1 to 11 carbon atoms. This is an organic residue.)
Hereinafter, the vinyl ether group-containing (meth) acrylate represented by the general formula (I) may be simply referred to as “compound of formula (I)”.

  When the composition according to this embodiment contains the compound of formula (I), the curability of the composition can be made excellent. Moreover, it is easy to suppress the viscosity of a composition low by containing the compound of Formula (I). Furthermore, rather than using a compound having a vinyl ether group and a compound having a (meth) acryl group separately, it is preferable to use a compound (monomer A) having both a vinyl ether group and a (meth) acryl group in one molecule. It is preferable for improving the curability of the composition.

In the general formula (I), the divalent organic residue having 2 to 20 carbon atoms represented by R ² may be linear, branched or cyclic substituted 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. Furthermore, R ² is an oxyethylene group, an oxy n-propylene group, an oxyisopropylene group, and an oxybutylene from the viewpoint of lowering the viscosity of the radiation-curable inkjet composition and further improving the curability. A compound having a glycol ether chain, which is an alkylene group having 2 to 9 carbon atoms having an oxygen atom by an ether bond in the structure of the group or the like, is more preferable.

In the general formula (I), 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 carboxyl 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 content of the compound of formula (I) is preferably 1% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and still more preferably, with respect to the total mass (100% by mass) of the composition. Is 10% by mass or more and 30% by mass or less, and particularly preferably 10% by mass or more and 25% by mass or less. When the content of the compound of formula (I) is 1% by mass or more, the viscosity of the composition can be reduced, and the curability of the composition can be further improved. On the other hand, when the content is 50% by mass or less, the storage stability of the ink can be maintained in an excellent state.

  Specific examples of the compound of the formula (I) are not particularly limited. For example, 2-vinyloxyethyl (meth) acrylate, 3-vinyloxypropyl (meth) acrylate, 1-methyl-2- (meth) acrylate Vinyloxyethyl, 2-vinyloxypropyl (meth) acrylate, 4-vinyloxybutyl (meth) acrylate, 1-methyl-3-vinyloxypropyl (meth) acrylate, 1-vinyloxymethylpropyl (meth) acrylate, ( 2-methyl-3-vinyloxypropyl (meth) acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth) acrylate, 3-vinyloxybutyl (meth) acrylate, 1-methyl-2-vinyl (meth) acrylate Loxypropyl, 2-vinyloxybutyl (meth) acrylate, 4-vinyloxycyclohexane (meth) acrylate Sil, 6-vinyloxyhexyl (meth) acrylate, 4-vinyloxymethylcyclohexylmethyl (meth) acrylate, 3-vinyloxymethylcyclohexylmethyl (meth) acrylate, 2-vinyloxymethylcyclohexyl (meth) acrylate Methyl, (meth) acrylic acid p-vinyloxymethylphenylmethyl, (meth) acrylic acid m-vinyloxymethylphenylmethyl, (meth) acrylic acid o-vinyloxymethylphenylmethyl, methacrylic acid 2- (2-vinylic acid) Loxyethoxy) ethyl, 2- (2-vinyloxyethoxy) ethyl acrylate (VEEA), 2- (vinyloxyisopropoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxy) propyl (meth) acrylate, (Meth) acrylic acid 2- (vinyloxyethoxy) isopropyl Pill, 2- (vinyloxyisopropoxy) propyl (meth) acrylate, 2- (vinyloxyisopropoxy) isopropyl (meth) acrylate, 2- (vinyloxyethoxyethoxy) ethyl (meth) acrylate, (meth) 2- (vinyloxyethoxyisopropoxy) ethyl acrylate, 2- (vinyloxyisopropoxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyisopropoxyisopropoxy) ethyl (meth) acrylate, (meth) acrylic 2- (vinyloxyethoxyethoxy) propyl acid, 2- (vinyloxyethoxyisopropoxy) propyl (meth) acrylate, 2- (vinyloxyisopropoxyethoxy) propyl (meth) acrylate, 2- (meth) acrylic acid 2- (Vinyloxyisopropoxyisopropoxy) propyl, 2- (vinyloxyethoxyethoxy) isopropyl (meth) acrylate, 2- (vinyloxyethoxyisopropoxy) isopropyl (meth) acrylate, 2- (vinyloxyisopropoxyethoxy) isopropyl (meth) acrylate, (meth) 2- (vinyloxyisopropoxyisopropoxy) isopropyl acrylate, 2- (vinyloxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2- (vinyloxyethoxyethoxyethoxyethoxy) ethyl (meth) acrylate, (meth) 2- (isopropenoxyethoxyethoxy) ethyl acrylate, 2- (isopropenoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxyethoxyethoxy) ethyl (meth) acrylate, (meth) acrylic acid 2- (Isopropeno Shi ethoxyethoxy ethoxyethoxy) ethyl, and (meth) Polyethylene glycol monovinyl ether acrylate, and (meth) acrylic acid polypropylene glycol monovinyl ether. Among these specific examples, VEEA: 2- (2-vinyloxyethoxy) ethyl acrylate is particularly preferable because it is easy to balance the curability and viscosity of the composition.

1.1.2. Monomer B
The radiation curable inkjet composition of the present embodiment has one (meth) acryloyloxy group or (meth) acryloyl group, the number of nitrogen atoms, and the (meth) acryloyloxy group and the (meth) acryloyl group. Contains a monomer B having a cyclic, linear or branched structure in which the total number of oxygen atoms other than oxygen atoms contained in is 2 or more.

The composition according to this embodiment contains 15% by mass or more of monomer B with respect to the total mass of the composition. Although the composition which concerns on this embodiment can make sclerosis | hardenability and a viscosity favorable by containing the monomer A, on the other hand, the point with a strong odor was a subject. The odor of a composition can be reduced because the composition which concerns on this embodiment contains the monomer B in the said range.

  The upper limit of the content of the monomer B in the composition according to the present embodiment is 50% by mass or less, preferably 49% by mass or less, more preferably 35% by mass or less, particularly with respect to the total mass of the composition. Preferably it is 30 mass% or less. When the upper limit value of the content of the monomer B is within the above range, both the low odor property of the composition itself and the low odor property of the cured film formed from the composition can be achieved. On the other hand, when the upper limit of the content of the monomer B exceeds the above range, the solubility of the polymerization initiator may be impaired, and the curability tends to be inferior.

  Monomer B is preferably a compound having a (meth) acryloyl group, and more preferably a compound in which a (meth) acryloyl group is directly bonded to a nitrogen atom. Moreover, it is preferable to contain at least any one of a nitrogen atom and an oxygen atom as an atom constituting the ring. Monomer B is preferably a compound having a cyclic skeleton. More preferably, the cyclic skeleton has a heterocyclic structure. With such a compound, the odor of the composition can be more suitably reduced. Moreover, the vaporization of the composition which concerns on this embodiment containing the monomer A is suitably suppressed by containing the monomer B, and the odor of a composition can be reduced suitably.

  Specific examples of monomer B include N-acryloylmorpholine (ACMO), N-methacryloylmorpholine, 1-acryloylpyrrolidin-2-one, 1-methacryloylpyrrolidin-2-one, 1-acryloylpiperidin-2-one, 1-methacryloylpiperidin-2-one, 2-hydroxy-3-phenoxypropyl (meth) acrylate, cyclic trimethylolpropane formal (meth) acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl ) Methyl (meth) acrylate, hydroxyethyl acrylamide (HEAA), hydroxyethyl methacrylamide, dimethylaminopropyl acrylamide (DMAPAA), dimethylaminopropyl methacrylamide and derivatives thereof.

  "The total number of nitrogen atoms and oxygen atoms is 2 or more" means having 2 or more nitrogen atoms, having 2 or more oxygen atoms, and having 2 or more nitrogen atoms and oxygen atoms in total. It includes cases.

  Of the above examples, the monomer B is more preferably an acrylamide. Furthermore, the monomer B is more preferably a compound having a cyclic skeleton. By being such a compound, there exists a tendency which can reduce an odor more suitably. Further, when the monomer B has a cyclic skeleton, the viscosity increase tends to be more suitably suppressed. From such a viewpoint, as monomer B, N-acryloylmorpholine (ACMO), hydroxyethylacrylamide (HEAA), and dimethylaminopropylacrylamide (DMAPAA) are preferable, and N-acryloylmorpholine (ACMO) is particularly preferable.

  Monomer B may be used individually by 1 type, and may be used in combination of 2 or more type. The upper limit of the total content of monomers B in the composition according to this embodiment is preferably 35% by mass or less, preferably 30% by mass or less, more preferably 25% by mass or less, with respect to the total mass of the composition. It is. When the upper limit value of the content of the monomer B is within the above range, the solubility of the initiator is not excessively deteriorated.

The lower limit of the content of the monomer B in the composition according to this embodiment is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 20% by mass or more with respect to the total mass of the composition. is there. When the lower limit value of the content of the monomer B is in the above range, the odor of the composition can be sufficiently reduced.

1.1.3. Monomer C
The inkjet composition of this embodiment contains the monomer C which is a monofunctional (meth) acrylate having an aromatic ring skeleton. Although the composition which concerns on this embodiment can reduce the odor resulting from the presence of the monomer A by containing the monomer B, the monomer B has the ability to dissolve the polymerization initiator described later. Is not high, and due to this, the curability of the composition tends to be insufficient. However, by containing the monomer C, the solubility of the initiator of the composition according to the present embodiment is good, and the curability of the composition can be good.

  A monofunctional (meth) acrylate having an aromatic ring skeleton is a compound having an aromatic ring skeleton and one (meth) acryloyl group in a molecule as a polymerizable functional group. Examples of monofunctional (meth) acrylates having an aromatic ring skeleton include, but are not limited to, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate (PEA), alkoxylated 2-phenoxyethyl (meth) acrylate, and ethoxylation. Nonylphenyl (meth) acrylate, alkoxylated nonylphenyl (meth) acrylate, p-cumylphenol EO modified (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate. As these commercially available products, for example, Biscoat # 192 (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name, phenoxyethyl acrylate), SR340 (phenoxyethyl methacrylate), SR339A (phenoxyethyl acrylate), SR504 (ethoxylated nonylphenyl acrylate) , CD614 (alkoxylated nonylphenyl acrylate), and CD9087 (alkoxylated 2-phenoxyethyl acrylate) (all are trade names manufactured by Sartomer).

  Among these, at least one of the compound represented by the following general formula (II) and the compound represented by the general formula (III) is preferable.

_{^{CH 2 = CR 4 -COOR 5 -Ar}} ··· (II)
^{_{CH 2 = CR 4 -COO-Ar}} ··· (III)
(In the above formulas (II) and (III), R ⁴ is a hydrogen atom or a methyl group. In the above formula (II), Ar representing an aromatic ring skeleton has at least one aryl group, and the aryl group carbon atoms constituting is a monovalent organic residue attached to the group represented by R5, also R ⁵ is a divalent organic residue having 1 to 4 carbon atoms. the above formula (III) In the formula, Ar representing an aromatic ring skeleton is a monovalent organic residue having at least one aryl group, and a carbon atom constituting the aryl group bonded to —COO— in the formula.
In the above general formula (II), the group represented by R ⁵ includes a linear, branched or cyclic alkylene group having 1 to 4 carbon atoms, and an ether in the structure. Preferable examples include an optionally substituted alkylene group having 1 to 4 carbon atoms having an oxygen atom by a bond and / or an ester bond. Among these, an alkylene group having 1 to 4 carbon atoms such as an ethylene group, an n-propylene group, an isopropylene group, and a butylene group, and an oxyethylene group, an oxy n-propylene group, an oxyisopropylene group, and an oxybutylene group An alkylene group having 1 to 4 carbon atoms having an oxygen atom due to an ether bond in the structure is suitably used. When the organic residue is a group that may be substituted, the substituent is not particularly limited, and examples thereof include a carboxyl group, an alkoxy group, a hydroxyl group, and a halo group, and the substituent includes a carbon atom. When it is a group, the carbon atom is counted in the carbon number of the organic residue.

In the above general formulas (II) and (III), the aryl group contained in at least one Ar (aryl) (aromatic ring skeleton) is not limited to the following, and examples thereof include a phenyl group and a naphthyl group. The number of aryl groups is 1 or more, preferably 1 or 2. The aryl group is a carbon atom bonded to the organic residue represented by R ⁵ in the formula (II), a carbon atom bonded to —COO— in the formula (III) among the carbon atoms constituting the group, and When it has two or more aryl groups, it may be substituted with a carbon atom other than the carbon atom that connects the aryl groups. When substituted, the number of substitutions per aryl group is 1 or more, preferably 1 or 2. Although it does not specifically limit as a substituent, For example, a C1-C10 linear, branched or cyclic alkyl group and alkoxy group, a carboxyl group, a halo group, and a hydroxyl group are mentioned.

  By containing the monomer C which is a monofunctional (meth) acrylate having an aromatic ring skeleton, the solubility of the photopolymerization initiator described later tends to be good, and the curability tends to be improved, which is preferable. In particular, when an acylphosphine oxide photopolymerization initiator or a thioxanthone photopolymerization initiator is used, the solubility tends to be good. Among monofunctional (meth) acrylates having an aromatic ring skeleton, phenoxyethyl (meth) acrylate and benzyl (meth) acrylate are preferred, but phenoxyethyl (meth) acrylate is more preferred because of its lower odor.

  Furthermore, compatibility with additives such as a photopolymerization initiator is improved, viscosity and odor can be further reduced, and reactivity (curability) can be further improved. ) Acrylates are preferred, and phenoxyethyl acrylate (PEA) is particularly preferred.

  The total content of the monofunctional (meth) acrylate having an aromatic ring skeleton is preferably 5% by mass or more and 40% by mass or less with respect to the total mass (100% by mass) of the ink composition. When the content is 5% by mass or more, the curability and the solubility of the photopolymerization initiator are good. On the other hand, if the content is 40% by mass or less, the curability is good. Further, the above content is more excellent in the solubility of the photopolymerization initiator and the curability of the composition. Preferably they are 15 mass% or more and 250 mass% or less.

1.1.4. Other Monomers The radiation curable inkjet composition of the present embodiment may contain monomers other than the monomer A, monomer B and monomer C. Examples of such monomers include, but are not limited to, various monomers and oligomers such as monofunctional, bifunctional, and trifunctional or more polyfunctional.

  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-vinylformamide, N-vinylcarbazole, N-vinylacetamide, N-vinyl N-vinyl compounds such as pyrrolidone and N-vinylcaprolactam; acrylamides such as dimethylacrylamide (DMAA) and dimethylaminoethyl acrylate benzyl chloride quaternary salt (DMAEA); 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, isodecyl (meth) acrylate (IDA), and isomyristyl. (Meth) acrylate, isostearyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, butoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate , 2-hydroxypropyl (meth) acrylate, lactone-modified flexible (meth) acrylate, t-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate DOO, dicyclopentenyl oxyethyl (meth) acrylate, 1,4-2- (meth) acrylic acid-dioxaspiro [4,5] deci-2-ylmethyl, and the like.

  Examples of the bifunctional (meth) acrylate include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and 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-bisphenol A (propylene oxide) adduct di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, and polytetramethylene glycol di (meth) acrylate.

  Examples of the trifunctional or higher polyfunctional (meth) acrylate include trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and 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 modification Dipentaerythritol hexa (meth) acrylate is mentioned.

  The total content of the bifunctional or higher polyfunctional (meth) acrylate is preferably 0.5% by mass or more and 50% by mass or less, more preferably 1% by mass with respect to the total mass (100% by mass) of the composition. It is more than 45 mass%, Most preferably, it is 2 mass% or more and 30 mass% or less. Further, it is more preferably 20% by mass or less, and still more preferably 15% by mass or less. By setting it as the said preferable range, it exists in the tendency which is excellent in coating-film stretchability.

The composition according to the present embodiment is a non-aqueous composition containing the largest amount of the polymerizable compound among the medium components in which solid components such as a photopolymerization initiator and a coloring material are dissolved or dispersed. It is preferable in terms of curability and storage stability. The medium component having the largest mass ratio among the medium components contained in the composition is a polymerizable compound. The total content of the polymerizable compounds is preferably 40% by mass to 95% by mass, more preferably 50% by mass or more, and further preferably 60% by mass or more, based on the total mass (100% by mass) of the composition. 90 mass% or less is more preferable, and 80 mass% or less is further more preferable. When the content of the polymerizable compound is within the above range, the viscosity and odor can be further reduced, and the solubility and reactivity of the photopolymerization initiator can be further improved.

  The content of the monomer other than the monomer A, the monomer B, and the monomer C is preferably 50% by mass with respect to the total mass (100% by mass) of the composition from the viewpoint of improving the curability of the composition. Hereinafter, more preferably 1% by mass to 45% by mass, and particularly preferably 5% by mass to 40% by mass.

1.2. Polymerization Initiator The composition according to the present embodiment contains a radiation polymerization initiator (hereinafter also referred to as a photopolymerization initiator or a polymerization initiator) that generates active species when irradiated with radiation as a polymerization initiator. It is preferable to do. The photopolymerization initiator is not particularly limited. For example, known photopolymerization such as alkylphenone photopolymerization initiator, acylphosphine oxide photopolymerization initiator, titanocene photopolymerization initiator, and thioxanthone photopolymerization initiator. Initiators are mentioned. Of these, acylphosphine oxide photopolymerization initiators are preferred. By containing an acylphosphine oxide photopolymerization initiator, the composition is excellent in curability, and in particular, it tends to be more excellent in curability by a curing process using UV-LED.

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

  Examples of commercially available acylphosphine oxide photopolymerization initiators include IRGACURE 819 (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide), IRGACURE 1800 (bis- (2,6-dimethoxybenzoyl)). A mixture of -2,4,4-trimethylpentylphosphine oxide and 1-hydroxy-cyclohexyl-phenylketone at a mass ratio of 25:75), IRGACURE TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide) (all above BASF) and the like. Further, among these, IRGACURE 819 and IRGACURE TPO are preferably used in combination. Since IRGACURE 819 has higher reactivity, and IRGACURE TPO has good reactivity and high solubility, it is possible to improve reactivity and solubility by using both in combination.

A photoinitiator may be used individually by 1 type and may be used in combination of 2 or more type. The total content of the photopolymerization initiator is preferably 1% by mass or more and 20% by mass or less, more preferably 3% in terms of excellent curability and solubility with respect to the total mass (100% by mass) of the composition. The content is from 5% by mass to 15% by mass, more preferably from 5% by mass to 10% by mass, and particularly preferably from 7% by mass to 9% by mass.
When an acylphosphine oxide photopolymerization initiator is contained as a photopolymerization initiator, it is preferably 1% by mass or more and 20% by mass or less, more preferably 1% by mass or more, based on the total mass (100% by mass) of the composition. It is 10 mass% or less, More preferably, it is 3 mass% or more and 9 mass% or less, Most preferably, it is 5 mass% or more and 8 mass% or less.

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 slip agent, a photosensitizer, 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, chelate azo pigments, etc., 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, the carbon black used in the black composition is 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 the pigment used in the white composition include C.I. I. Pigment white 6, 18, and 21.

  Examples of the pigment used in the yellow composition 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 the pigment used in the magenta composition 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 the pigment used in the cyan composition 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. Moreover, 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 size 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. Direct 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 total content of the color materials 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 for 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 Co., Ltd., Ajisper Series, Solsperse Series (Solsperse 36000 available from Avecia and Noveon)
Etc.), Dispervic series manufactured by BYK Additives & Instruments, and Dispalon 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. Other polymerization inhibitors include, but are not limited to, for example, p-methoxyphenol, hydroquinone monomethyl ether (MEHQ), 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 total content of the polymerization inhibitor is preferably 0.05% by mass or more and 0.5% by mass, more preferably 0.1% by mass or more and 0.5% by mass with respect to the total mass (100% by mass) of the composition. It is below mass%.

<Slip agent>
The composition according to this embodiment may further contain a slip agent. As the slip agent, 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. A slip agent may be used individually by 1 type, and may be used in combination of 2 or more type.

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

<Photosensitizer>
The composition according to this embodiment may further contain a photosensitizer. Photosensitizers 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 a condensate of acetaldehyde and diamine), chlorine compounds (tetrachloride) Arsenide, 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 the composition in an environment of 20 ° C. can do.

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 the present embodiment, the composition is prepared by subjecting a mixture obtained by mixing the photopolymerization initiator and at least a part of the polymerizable compound to at least one of ultrasonic treatment and heating treatment in the course of preparation. It is preferable to have a process. 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. Inkjet Recording Method An inkjet recording method according to the present embodiment includes a step of attaching the radiation curable inkjet composition to a recording medium, and a UV-LED (ultraviolet light emission) with respect to the radiation curable inkjet composition on the recording medium. A step of irradiating light from a diode). In this way, a cured film is formed at the location where the composition is applied on the recording medium.

<Adhesion process>
In the step of depositing the composition on 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.

  The recording medium is not particularly limited, and examples thereof include plastics such as polyvinyl chloride, polyethylene terephthalate, polypropylene, polyethylene, and polycarbonate, those whose surfaces are processed, glass, coated paper, and the like.

<Curing process (light irradiation process)>
Next, in the curing step, the composition applied on the recording medium is cured by irradiation with UV-LED light. In other words, the coating film of the composition formed on the recording medium becomes a cured film by irradiation with UV-LED light. This is because the photopolymerization initiator that can be contained in the composition is decomposed by irradiation with ultraviolet rays to generate active species (initiating species) such as radicals, acids, and bases, and the polymerization reaction of the photopolymerizable compound This is because it is promoted by the function of the starting species. 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 photopolymerization initiator in the composition, the sensitizing dye in the system absorbs actinic radiation to be in an excited state and contacts the photopolymerization initiator to decompose 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.

  Further, the temperature of the recording medium during recording is preferably less than 45 ° C., more preferably 40 ° C. or less, and particularly preferably 35 ° C. or less. By setting the temperature of the recording medium at the time of recording within the above range, the temperature of the recording medium is smaller than the mol average Tg of the monofunctional monomer in the above composition, so that the monomer to the atmosphere after forming the coating film Volatilization is suppressed, and low odor can be achieved.

3. Examples and Comparative Examples Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

3.1. Preparation of Inkjet Composition First, a part of each of the coloring material, the dispersing agent and each monomer 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 and stirred to polymerize the coloring material. A pigment dispersion liquid dispersed in the organic compound was obtained. Next, after the remaining monomer, the polymerization initiator and the polymerization inhibitor are put into a mixture tank which is a stainless steel container so that the composition shown in Table 1 or 2 is obtained, the mixture is stirred and completely dissolved. The pigment dispersion obtained above was added, mixed and stirred at room temperature for 1 hour, and filtered through a 5 μm membrane filter to obtain ink jet compositions of Examples and Comparative Examples. In addition, the numerical value of each component shown in each Example and each comparative example in a table | surface represents the mass%.

  The abbreviation components used in the table are as follows.

<Polymerizable compound>
(Monomer A)
VEEA (trade name, manufactured by Nippon Shokubai Co., Ltd., 2- (2-vinyloxyethoxy) ethyl acrylate)
(Monomer B)
・ ACMO (trade name, manufactured by KJ Chemicals, acryloylmorpholine)
・ HEAA (trade name, manufactured by KJ Chemicals, hydroxyethylacrylamide)
・ DMAPAA (trade name, manufactured by KJ Chemicals, dimethylaminopropylacrylamide)
(Monomer C)
・ PEA (trade name “Biscoat # 192, manufactured by Osaka Organic Chemical Industry Co., Ltd., phenoxyethyl acrylate”)
(Other monomers)
DMAEA (trade name “DMAEA-BQ”, manufactured by KJ Chemicals Co., Ltd., dimethylaminoethyl acrylate benzyl chloride quaternary salt)
・ DMAA (trade name, manufactured by KJ Chemicals, dimethylacrylamide)
・ IDA (trade name, manufactured by BASF Japan Ltd., isodecyl acrylate)
(Polyfunctional monomer)
・ DPHA (trade name, manufactured by Daicel Ornex Co., Ltd., dipentaerythritol hexaacrylate)
<Photopolymerization initiator>
IRGACURE 819 (Irq. 819) (trade name, manufactured by BASF, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide)
・ TPO (trade name “IRGACURE TPO”, manufactured by BASF, 2,4,6-trimethylbenzoyldiphenylphosphine oxide)
<Polymerization inhibitor>
MEHQ (trade name “p-methoxyphenol”, manufactured by Kanto Chemical Co., Inc., hydroquinone monomethyl ether)
<Slip agent>
BYK-UV3500 (trade name, manufactured by BYK Additives & Instruments, polyether-modified polydimethylsiloxane having an acrylic group)
<Color material>
・ Carbon black (trade name “MA-100”, manufactured by Mitsubishi Chemical Corporation)
<Dispersant>
Solsperse 36000 (trade name, manufactured by Lubrizol, a polymer dispersant).

3.2. Evaluation Method (1) Evaluation of Odor Strength of Inkjet Composition The odor of each composition obtained above was directly sniffed immediately after preparation, and evaluated based on the following evaluation criteria.

(Evaluation criteria)
A: Odorless B: Finally an odor that can be sensed C: A weak odor that tells what odor it is D: An odor that can be easily detected.

(2) Evaluation of curability Ink printing and curing were performed as follows. First, a PET film with a receiving layer is affixed and transported on a table of a transport unit configured to transport a test sample in a straight line, and an ink jet composition is ejected from the ink jet head on the way. The printed sample was irradiated with light through the bottom of the sheet, and the curability at that time was confirmed by a finger erosion test. Printing was performed at a resolution of 720 dpi × 720 dpi, and the ink weight at the time of printing was 14 ng / dot. The temperature of the print sample at the time of printing was 35 ° C. The irradiation intensity of the printing surface of the irradiator was 1 W / cm ² . The print sample was printed with a size of 1 inch × 1 inch. The amount of energy was adjusted by changing the sample transport speed. Irradiation energy (unit: mJ / cm ² ) required for irradiating ultraviolet rays from a UV-LED having a peak wavelength at 395 nm and curing the ink was measured for the inkjet compositions of each Example and each Comparative Example. . Irradiation of ultraviolet rays necessary for curing is performed until the sticky print pattern is touched and no stickiness is felt, and the integrated light amount at that time is measured by an integrated light meter UM-40 (Konica Minolta Holdings, Inc.). ). The evaluation criteria are as follows. The evaluation results are shown in Tables 1 and 2.

A: Integrated light quantity is 200 mJ / cm ² or less B: Integrated light quantity is more than 200 mJ / cm ² and 350 mJ / cm ² or less C: Integrated light quantity is more than 350 mJ / cm ² and 500 mJ / cm ² or less D: Integrated light quantity is 500 mJ / cm ² or less ^More than ² .

(3) Evaluation of viscosity Viscosity was evaluated about the inkjet composition of each Example and each comparative example. After preparing an ink jet composition using a vibration type viscometer (MV100 model number, manufactured by Yamaichi Electronics Co., Ltd.), the viscosity of the ink jet composition when 1 hour has passed is measured and evaluated according to the following criteria. 2. The measurement temperature was 20 ° C.

A: Over 4 mPa · s, 6 mPa · s or less B: Over 6 mPa · s, 8 mPa · s or less C: Over 8 mPa · s D: Over 10 mPa · s D: Over 10 mPa · s.

(4) Solubility of polymerization initiator For each ink jet composition, an ink composition without pigment was similarly prepared using only the other components without adding the pigment and pigment dispersant components, and sufficiently stirred. Thereafter, whether or not the photopolymerization initiator remained undissolved was visually evaluated. For samples in which the photopolymerization initiator was not dissolved, the ink composition was placed in a thermostatic bath at 0 ° C., taken out after 24 hours and returned to room temperature, and then the photopolymerization initiator was deposited in the ink composition. This was visually observed again. The evaluation criteria are as follows. The evaluation results are shown in Tables 1 and 2.

A: No dissolution or precipitation of photopolymerization initiator was observed after stirring at room temperature and after storage at 0 ° C. B: No photopolymerization initiator was dissolved after stirring at room temperature, but light after storage at 0 ° C. C: Precipitation of polymerization initiator was observed: Undissolved residue of photopolymerization initiator was observed after stirring at room temperature.

(5) Stretchability of coating film Each ink composition was applied on a polyvinyl chloride film (JT5829R, manufactured by MACtac) with a bar coater so as to have a thickness of 10 μm. Subsequently, using a metal halide lamp (manufactured by Eye Graphics Co., Ltd.), it was cured with an energy of 400 mJ / cm ² to form a coating film. The release film of the polyvinyl chloride film on which the coating film was formed was peeled off and cut into strips having a width of 1 cm and a length of 8 cm to prepare test pieces. About the test piece of each ink composition, the elongation rate as stretchability was measured using the tensile tester (TENSILON, the product made by ORIENTEC). The elongation rate was a value at the time when the crack occurred. The index of evaluation is as follows.
A: 40% or more and less than 80% B: 20% or more and less than 40% C: Less than 20%.

3.3. Evaluation Results Tables 1 and 2 show the compositions of the radiation curable inkjet compositions used in Examples and Comparative Examples, and the evaluation results.

  From Table 1 and Table 2, the radiation curable inkjet compositions of Examples 1 to 20 according to the present invention had low odor and good curability.

  On the other hand, the composition of the comparative example 1 which contains the monomer B in total less than 15 mass% (5 mass%) with respect to the total mass had strong odor intensity | strength. Moreover, it has one (meth) acryloyloxy group or (meth) acryloyl group, the number of nitrogen atoms, and the number of oxygen atoms other than oxygen atoms contained in the (meth) acryloyloxy group and the (meth) acryloyl group The compositions of Comparative Examples 2 to 4 using the compounds having the sum of 1 or 0 also had strong odor intensity. Furthermore, the odor intensity was strong also about the composition of the comparative example 5 which does not contain the monomer B.

  Moreover, the composition of Comparative Examples 6-8 which does not contain the monomer A or the monomer C was insufficient in curability. Furthermore, it is considered that the composition of Comparative Example 8 that does not contain monomer C has poor initiator solubility, and thus has poor curability.

  Moreover, when each Example was seen, it turned out that dipropylene glycol diacrylate does not have big influence on odor intensity | strength, sclerosis | hardenability, and a viscosity by the some among polyfunctional monomers. The composition of Comparative Example 1 was changed to ACMO 5 mass%, VEEA 26 mass%, PEA 26 mass%, dipropylene glycol diacrylate 25 mass%, and DPHA 7 mass% (other compositions are comparative examples) The evaluation of odor intensity was also B for 1). From this, it can be seen that in Comparative Example 1, a large amount of dipropylene glycol does not cause a decrease in odor intensity. Further, in Examples 8, 9, 10, 12, and 14, when the linear or branched HEAA or DMPAA is used as the monomer B, compared with the case where ACMO having a cyclic structure is used, the ink jet composition is used. It was found that the viscosity of the product tends to increase. That is, it has been found that the use of a compound having a cyclic structure as the monomer B is more advantageous in terms of ejection stability of the ink jet composition.

  Moreover, when Example 18 was seen, as the monomer C, it turned out that the direction which uses PEA has a higher odor reduction effect than the case where benzyl acrylate is used. This is thought to be due to the difference in molecular structure, but details are unknown.

  Further, when Example 19 is used, when only bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irq. 819) is used as the polymerization initiator, the reactivity is high but the solubility is low. The solubility of the initiator was slightly inferior. Further, in Example 20, when only 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO) is used, it is considered that the solubility is good, but the reactivity is not so high, and the curability is slightly higher. I found it inferior.

The present invention is not limited to the above-described embodiments, and various modifications can be made. 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 exhibits the same operational effects 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 (15)

Monomer A represented by the following general formula (I):
_{^{CH 2 = CR 1 -COOR 2 -O}} -CH = CH-R 3 ··· (I)
(In Formula (I), R ¹ is a hydrogen atom or a methyl group, R ² is a divalent organic residue having 2 to 20 carbon atoms, and R ³ is a hydrogen atom or a monovalent having 1 to 11 carbon atoms. This is an organic residue.)
One (meth) acryloyloxy group or one (meth) acryloyl group, the number of nitrogen atoms, and the number of oxygen atoms other than oxygen atoms contained in the (meth) acryloyloxy group and the (meth) acryloyl group A monomer B having a cyclic, linear or branched structure, the total of which is 2 or more;
Monomer C which is a monofunctional (meth) acrylate having an aromatic ring skeleton,
Containing
A radiation-curable inkjet composition containing the monomer B in a total amount of 15% by mass or more based on the total mass. In claim 1,
A radiation-curable inkjet composition containing the monomer B in a total amount of 15% by mass to 49% by mass with respect to the total mass. In claim 1 or claim 2,
The monomer C is a compound represented by the following general formula (II), and
_{^{CH 2 = CR 4 -COOR 5 -Ar}} ··· (II)
Following compound represented by general formula ^{_{(III) CH 2 = CR 4}} -COO-Ar ··· (III)
A radiation curable inkjet composition which is at least one of the following.
(In the above formulas (II) and (III), R ⁴ is a hydrogen atom or a methyl group. In the above formula (II), Ar representing an aromatic ring skeleton has at least an aryl group and constitutes the aryl group. In which the carbon atom to be bonded is a monovalent organic residue bonded to the group represented by R ⁵ , and R ⁵ is a divalent organic residue having 1 to 4 carbon atoms. Ar representing an aromatic ring skeleton is a monovalent organic residue having at least an aryl group, and a carbon atom constituting the aryl group bonded to —COO— in the formula. In any one of Claims 1 to 3,
A radiation curable inkjet composition containing an acylphosphine oxide photopolymerization initiator. In claim 4,
A radiation curable inkjet composition containing the acylphosphine oxide photopolymerization initiator in a total amount of 1% by mass to 10% by mass with respect to the total mass. In any one of Claims 1 thru | or 5,
The monomer B is a radiation curable inkjet composition, which is a compound having a cyclic skeleton. In any one of Claims 1 thru | or 6,
A radiation-curable inkjet composition containing the monomer A in a total amount of 10% by mass to 30% by mass with respect to the total mass. In any one of Claims 1 thru | or 7,
A radiation-curable inkjet composition containing the monomer C in a total amount of 10% by mass to 30% by mass with respect to the total mass. In any one of Claims 1 thru | or 8,
The monomer A is a radiation curable inkjet composition, which is a compound having a glycol ether chain. In any one of Claims 1 thru | or 9,
The monomer B is a radiation curable inkjet composition, which is an acrylamide. In any one of Claims 1 thru | or 10,
A radiation curable ink jet composition having a total content of polyfunctional (meth) acrylate of 30% by mass or less. Attaching the radiation curable inkjet composition according to any one of claims 1 to 11 to a recording medium;
Irradiating the radiation curable inkjet composition with UV-LED light. In claim 12,
The ink jet recording method, wherein the irradiation energy of the UV-LED is 50 to 1000 mJ / cm ² . In claim 12 or claim 13,
The inkjet recording method, wherein the irradiation intensity of the UV-LED is 10 to 1000 mW / cm ² . In any one of claims 12 to 14,
The inkjet recording method, wherein the temperature of the recording medium in the step of attaching to the recording medium is less than 45 ° C.