JP2013142104A - Energy ray-curable inkjet ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy ray-curable inkjet ink composition having high adhesion onto recording medium surfaces made of various materials, and having excellent extensibility after being cured.SOLUTION: In this energy ray-curable inkjet ink composition containing a coloring material and a polymerizable monomer, the polymerizable monomer contains a monofunctional monomer having an aromatic hydrocarbon-based cyclic structure in the molecule and a monofunctional monomer having an aliphatic hydrocarbon-based cyclic structure in the molecule, and 90 mass% or more of the polymerizable monomer is the monofunctional monomer.

Description

  The present invention relates to an energy ray curable inkjet ink composition. More specifically, the present invention relates to an energy beam curable inkjet ink composition that has high adhesion to the surface of a recording medium made of various materials and realizes excellent stretchability that has never been achieved after curing. The energy beam curable inkjet ink composition of the present invention can be used as either an image forming ink or a primer ink.

  An ink jet system that discharges ink from an ink nozzle head as droplets is applied to many printers because it is small and inexpensive, and can form an image without contact with the surface of a recording medium. Recently, commercial printing and industrial printing using an ink jet printer have been performed for advertisements, posters, decorations, etc., and this includes the surface of non-permeable recording media such as plastics. There is a strong demand to enable printing on recording media of various materials and to realize a printing surface with higher image quality.

  In order to meet such demands, research has been conducted on inkjet ink compositions that can be printed on the surface of various materials including non-permeable recording media by improving the configuration of inkjet ink compositions used in inkjet printers. For example, an energy beam curable inkjet ink composition containing a reactive liquid substance containing monofunctional and polyfunctional monomers and oligomers and having a specific viscosity, and oligomers and heterocyclic radiation curable monomers as polymerizable compounds In addition, energy ray curable inkjet ink compositions containing an alkoxylated monomer have been proposed (Patent Documents 1 and 2).

JP 2001-525479 A JP 2004-514014 A

  However, the conventional energy ray curable inkjet ink composition as described above imparts quick drying properties to the ink composition for the purpose of preventing bleeding of the formed image and improving the quality of the formed image. In order to increase the adhesion of the ink composition to the surface of the recording medium, a polymerizable compound having a relatively high curability is used. For this reason, when the print surface formed using these ink compositions is stretched together with the recording medium after printing, the printed image is cracked or peeled, and the stretchability is poor. Therefore, it has been difficult to apply to a use in which a printed image is stretched with a recording medium after printing, such as a marking film or a three-dimensional stereoscopic display member.

  The object of the present invention is to have excellent adhesion to recording media made of various materials including the surface of a non-permeable recording medium, and further, excellent flexibility and unprecedented print image after printing. An object of the present invention is to provide an energy ray curable inkjet ink composition that realizes stretchability.

The present invention provides the following [1] to [8].
[1] An energy ray curable inkjet ink composition containing a colorant and a polymerizable monomer, wherein the polymerizable monomer has a monofunctional monomer having an aromatic hydrocarbon ring structure in the molecule and the molecule An energy ray curable inkjet ink composition comprising a monofunctional monomer having an aliphatic hydrocarbon-based cyclic structure, wherein 90% by mass or more of the polymerizable monomer is a monofunctional monomer.
[2] The energy ray-curable inkjet ink composition according to [1], wherein the monofunctional monomer having an aromatic hydrocarbon-based cyclic structure includes 2-hydroxy-3-phenoxypropyl acrylate.
[3] Monofunctional monomers having an aliphatic hydrocarbon ring structure include isobornyl acrylate, cyclohexyl acrylate, 3,5,5-trimethylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl. The energy beam curable inkjet ink composition according to the above [1] or [2], which contains at least one selected from the group consisting of acrylate and dicyclopentanyl acrylate.
[4] The above [1] to [1] containing the monofunctional monomer having an aromatic hydrocarbon ring structure and the monofunctional monomer having an aliphatic hydrocarbon ring structure in a mass ratio of 1:10 to 10: 1. 3] The energy ray curable inkjet ink composition according to any one of [3].
[5] The energy beam curable inkjet ink composition according to any one of [1] to [4], wherein the polymerizable monomer contains 2-hydroxy-3-phenoxypropyl acrylate and isobornyl acrylate.
[6] Any of the above-mentioned [1] to [5], which contains at least one photopolymerization initiator selected from the group consisting of a thioxanthone-based initiator, an acylphosphine oxide-based initiator, and an α-aminoalkylphenone-based initiator. An energy ray curable inkjet ink composition according to claim 1.
[7] The energy ray curable inkjet ink composition according to any one of [1] to [6], which is used as an image forming ink.
[8] The energy ray curable inkjet ink composition according to any one of [1] to [6], which is used as a primer ink.

  According to the present invention, an energy beam curable inkjet ink composition having high adhesion to the surface of a recording medium made of various materials and realizing excellent flexibility and stretchability after curing. Can be provided.

  Hereinafter, the present invention will be described in detail.

(Polymerizable compound)
The energy beam curable inkjet ink composition of the present invention (hereinafter sometimes referred to as “the ink composition of the present invention”) is a monofunctional compound having an aromatic hydrocarbon-based cyclic structure in the molecule as a polymerizable compound. It contains a monomer and a monofunctional monomer having an aliphatic hydrocarbon-based cyclic structure in the molecule.

  In the present invention, a monofunctional monomer having an aromatic hydrocarbon-based cyclic structure in the molecule (hereinafter sometimes referred to as “aromatic cyclic structure monofunctional monomer”) means one unsaturated bond in the molecule. And a polymerizable monomer having a cyclic structure of one or more aromatic hydrocarbons. Examples of the cyclic structure of the aromatic hydrocarbon include an aromatic hydrocarbon ring structure such as a monocyclic aromatic group such as benzene and a polycyclic aromatic group such as naphthalene and anthracene. As the unsaturated bond, an ethylenic double bond is preferable. The ethylenic double bond preferably has a (meth) acryloyloxy group, (meth) acrylamide group, vinyl group or vinyl ether group in the molecule, and particularly preferably has a (meth) acryloyloxy group.

Examples of such aromatic cyclic structure monofunctional monomers include benzyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate (2-HPA), 2-methacryloyloxyhexahydrophthalic acid, 2-methacryloyloxyethyl-2-hydroxypropylphthalic acid, EO-modified phenol (meth) acrylate, EO-modified cresol (meth) acrylate, EO-modified nonylphenol (meth) acrylate, PO-modified nonylphenol (meth) a Having one or more aromatic hydrocarbon cyclic structure in the molecule, such as relations (meth) acrylate compounds. Also, for example, styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid methyl ester, 3-methyl Styrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene, 3-octyl Styrene, 4-octylstyrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allyl styrene, isopropenyl styrene, butenyl styrene, octenyl styrene, 4-t- Aromatic vinyl compounds such as toxoxycarbonyl styrene, 4-methoxy styrene and 4-t-butoxy styrene, and one or more aromatic hydrocarbons in the molecule such as benzyl vinyl ether, phenyl ethyl vinyl ether and phenoxy polyethylene glycol vinyl ether. Vinyl ether compounds having a cyclic structure can also be used. These can be used alone or in combination of two or more. In particular, the ink composition of the present invention preferably contains, as the aromatic cyclic structure monofunctional monomer, a (meth) acrylate compound having one or more aromatic hydrocarbon-based cyclic structures in the molecule. It is more preferable to contain -3-phenoxypropyl acrylate. By containing 2-hydroxy-3-phenoxypropyl acrylate, it is possible to obtain an ink composition having sufficient stretchability while ensuring excellent adhesion to recording media of various materials.
In the present specification, “(meth) acrylate” represents acrylate or methacrylate, and notations such as “(meth) acryloyloxy” and “(meth) acrylamide” have the same meaning.

  In the present invention, a monofunctional monomer having an aliphatic hydrocarbon-based cyclic structure in the molecule (hereinafter sometimes referred to as “alicyclic structure monofunctional monomer”) means one unsaturated bond in the molecule. And a polymerizable monomer having one or more alicyclic hydrocarbon structures. Examples of the alicyclic hydrocarbon structure include aliphatic cyclic structures such as a cycloalkane skeleton, an admantane skeleton, and a norbornane skeleton. As the unsaturated bond, an ethylenic double bond is preferable. The ethylenic double bond preferably has a (meth) acryloyloxy group, (meth) acrylamide group, vinyl group or vinyl ether group in the molecule, and particularly preferably has a (meth) acryloyloxy group.

  Such alicyclic monofunctional monomers include cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) ) (Meth) acrylate compounds having an alicyclic hydrocarbon structure in the molecule such as acrylate, 3,5,5-trimethylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate and dicyclopentanyl acrylate It is done. In addition, vinyl ether compounds having an alicyclic hydrocarbon structure in the molecule such as cyclohexyl vinyl ether, cyclohexyl methyl vinyl ether, 4-methyl cyclohexyl methyl vinyl ether, and 4-hydroxymethyl cyclohexyl methyl vinyl ether can also be used. These can be used alone or in combination of two or more. In particular, the ink composition of the present invention preferably contains a (meth) acrylate compound having an alicyclic hydrocarbon structure in the molecule as the alicyclic structure monofunctional monomer, and includes isobornyl acrylate, cyclohexyl acrylate, 3 Containing at least one selected from the group consisting of 5,5-trimethylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate and dicyclopentanyl acrylate More preferred. By containing at least one selected from the above group as the polymerizable monomer, an ink composition having sufficient stretchability is obtained while ensuring excellent adhesion to recording media of various materials. be able to.

  In a preferred embodiment of the present invention, the ink composition of the present invention contains 2-hydroxy-3-phenoxypropyl acrylate and isobornyl acrylate as polymerizable monomers.

  The ink composition of the present invention comprises an aromatic cyclic structure monofunctional monomer and an alicyclic structure monofunctional monomer in an aromatic cyclic structure monofunctional monomer: alicyclic structure monofunctional monomer of 1:10 to 10: 1. It is preferably contained in a mass ratio, more preferably contained in a mass ratio of 1: 5 to 5: 1, and particularly preferably contained in a mass ratio of 1: 4 to 3: 2. By containing these two types of monofunctional monomers in the above ranges, sufficient stretchability and adhesion can be imparted to the resulting ink composition.

  In addition to the monofunctional monomer having an aromatic hydrocarbon ring structure in the molecule and the monofunctional monomer having an aliphatic hydrocarbon ring structure in the molecule, the ink composition of the present invention includes, as a polymerizable compound: The monofunctional monomer which has a structure different from the said 2 types of monofunctional monomer may be contained. Such a monofunctional monomer is not particularly limited as long as it is a compound that can be polymerized by an active radical generated from a photopolymerization initiator by the action of light, and a conventionally known monofunctional monomer may be used in this field. Can be used.

  The monofunctional monomer that the ink composition of the present invention can contain in addition to the two monofunctional monomers is a polymerizable monomer having one ethylenic double bond in a molecule having a property of being cured by energy rays, for example. Examples thereof include monofunctional (meth) acrylate compounds, (meth) acrylamide compounds, and monofunctional vinyl ether compounds.

  Specific examples of the monofunctional (meth) acrylate compound include, for example, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, tert-octyl (meth) acrylate, isoamyl (meth) acrylate, Decyl (meth) acrylate, isodecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, 2-ethylhexyl diglycol (meth) acrylate, butoxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 4-bromobutyl (meth) acrylate, cyanoethyl (meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, alkoxymethyl (meth) acrylate Lilate, alkoxyethyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate 1H, 1H, 2H, 2H-perfluorodecyl (meth) acrylate, glycidyl (meth) acrylate, glycidyloxybutyl (meth) acrylate, glycidyloxyethyl (meth) acrylate, glycidyloxypropyl (meth) acrylate, Tetrahydrofurfuryl (meth) acrylate, hydroxyalkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy Til (meth) acrylate, 4-hydroxybutyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, trimethoxysilylpropyl ( (Meth) acrylate, trimethylsilylpropyl (meth) acrylate, polyethylene oxide monomethyl ether (meth) acrylate, oligoethylene oxide monomethyl ether (meth) acrylate, polyethylene oxide (meth) acrylate, oligoethylene oxide (meth) acrylate, oligoethylene oxide monoalkyl ether (meta ) Acrylate, polyethylene oxide monoalkyl ether (meth) acrylate , Dipropylene glycol (meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, oligopropylene oxide monoalkyl ether (meth) acrylate, 2-methacryloyloxyethyl succinic acid, butoxydiethylene glycol (meth) acrylate, trifluoroethyl ( And (meth) acrylate, perfluorooctylethyl (meth) acrylate, and EO-modified-2-ethylhexyl (meth) acrylate.

  Specific examples of the (meth) acrylamide compound include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, Nn-butyl (meth) ) Acrylamide, Nt-butyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, (meth) acryloylmorpholine, etc. are mentioned.

  Specific examples of the monofunctional vinyl ether compound include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl. Vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, polyethylene Recall vinyl ether, chloroethyl vinyl ether, etc. chlorobutyl vinyl ether and chloroethoxyethyl vinyl ether.

  Among them, as the monofunctional monomer other than the aromatic cyclic structure monofunctional monomer and the alicyclic structure monofunctional monomer that can be contained in the ink composition of the present invention, a monofunctional (meth) acrylate compound is preferable, and isooctyl acrylate, 2 -Ethylhexyl acrylate and tetrahydrofurfuryl acrylate are particularly preferred. These monofunctional monomers are suitable for preparing a low viscosity ink composition.

  When the ink composition of the present invention contains a monofunctional monomer other than the aromatic cyclic structure monofunctional monomer and the alicyclic structure monofunctional monomer, the content of the aromatic cyclic structure monofunctional monomer and the alicyclic structure It is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass in total of the monofunctional monomers. Although the lower limit is not particularly limited, if the content of the monofunctional monomer other than the aromatic cyclic structure monofunctional monomer and the alicyclic structure monofunctional monomer is large, the adhesion to the surface of the recording medium may decrease, The smaller the content of the monofunctional monomer other than the aromatic cyclic structure monofunctional monomer and the alicyclic structure monofunctional monomer, the better. Therefore, the monofunctional monomer constituting the ink composition of the present invention may be only an aromatic cyclic structure monofunctional monomer and an alicyclic structure monofunctional monomer.

  Furthermore, the ink composition of the present invention may contain a polyfunctional monomer and / or a polymerizable oligomer as the polymerizable compound. The polyfunctional monomer and polymerizable oligomer are not particularly limited as long as they are compounds that can be polymerized by active radicals generated from a photopolymerization initiator by the action of light, and conventionally known ones can be used. . In the present specification, “oligomer” refers to those having a weight average molecular weight of 800 or more and 10,000 or less, and “weight average molecular weight” means a weight average molecular weight in terms of polystyrene measured by GPC (Gel Permeation Chromatography). To do. Generally, the coating film strength of the surface of the printed matter obtained using the ink composition can be improved by containing a polyfunctional monomer. Further, by containing a polymerizable oligomer, excellent flexibility and stretchability can be imparted to the ink composition.

  The polyfunctional monomer that can be contained in the ink composition of the present invention is a polymerizable monomer having two or more unsaturated bonds in a molecule having a property of polymerizing by energy rays. For example, bifunctional, trifunctional, tetrafunctional, pentafunctional and hexafunctional polyfunctional (meth) acrylate compounds and polyfunctional vinyl ether compounds having an ethylenic double bond as an unsaturated bond can be used.

As a bifunctional (meth) acrylate compound, specifically, for example,
1,6-hexanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2,4-dimethyl-1,5-pentanediol di (meth) acrylate , Butylethylpropanediol (meth) acrylate, ethoxylated cyclohexanemethanol di (meth) acrylate, polyethylene glycol di (meth) acrylate, oligoethylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, 2-ethyl- 2-butyl-butanediol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, EO-modified bisphenol A di (meth) acrylate, bisphenol F polyethoxydi (meth) Acrylate, polypropylene glycol di (meth) acrylate, oligopropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 2-ethyl-2-butylpropanediol di (meth) acrylate, 1,9- Nonane (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate and tricyclodecane di (meth) acrylate.

Examples of trifunctional (meth) acrylate compounds include:
Trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane alkylene oxide modified tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, trimethylol Propane tris ((meth) acryloyloxypropyl) ether, isocyanuric acid alkylene oxide modified tri (meth) acrylate, dipentaerythritol propionate tri (meth) acrylate, tris ((meth) acryloyloxyethyl) isocyanurate, hydroxypivalaldehyde Modified dimethylolpropane tri (meth) acrylate, sorbitol tri (meth) acrylate, propoxylated trimethylolpro Entry (meth) acrylate, and ethoxylated glycerin triacrylate, and the like.

  Tetrafunctional (meth) acrylates include pentaerythritol tetra (meth) acrylate, sorbitol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate propionate and ethoxylated pentaerythritol. Tetra (meth) acrylate, etc., pentafunctional (meth) acrylate, sorbitol penta (meth) acrylate and dipentaerythritol penta (meth) acrylate, etc., and hexafunctional (meth) acrylate, dipentaerythritol hexa (meth) Acrylate, sorbitol hexa (meth) acrylate, phosphazene alkylene oxide modified hexa (meth) acrylate and caprolactone modified dipenta Risuri Tall hexa (meth) acrylate, and the like.

Polyfunctional vinyl ether compounds include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, etc. Divinyl ethers of
Trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide Addition trimethylolpropane trivinyl ether, ethylene oxide addition ditrimethylolpropane tetravinyl ether, propylene oxide addition ditrimethylolpropane tetravinyl ether, ethylene oxide addition pentaerythritol tetravinyl ether, propylene oxide addition pentaerythritol te La ether, ethylene oxide adduct of dipentaerythritol hexavinyl ether, polyfunctional vinyl compounds such as propylene oxide adduct of dipentaerythritol hexa vinyl ether.

Examples of the polymerizable oligomer that can be contained in the ink composition of the present invention include a urethane acrylate oligomer, a polyester acrylate oligomer, and an epoxy acrylate oligomer.
Examples of the urethane acrylate oligomer include a reaction product of an isocyanate compound obtained by reacting a polyol and a polyvalent isocyanate and a (meth) acrylate having a hydroxy group. Examples of the isocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, hydrogenated xylylene diisocyanate, and examples of the (meth) acrylate having a hydroxy group include 2-hydroxyethyl acrylate.
The polymerizable oligomer is preferably a urethane acrylate oligomer, a polyester acrylate oligomer, an epoxy acrylate oligomer, or a mixture thereof, and more preferably a urethane acrylate oligomer. Moreover, as a urethane acrylate oligomer, the aliphatic urethane acrylate oligomer which consists of aliphatic isocyanate and the acrylate which has a hydroxyl group from a viewpoint of being easy to provide adhesiveness and obtaining a softness | flexibility etc. is preferable.

  In the present invention, the proportion of the monofunctional monomer in the total amount of polymerizable monomers contained in the ink composition of the present invention is 90% by mass or more, and preferably 95% by mass or more. Moreover, all the polymerizable monomers contained may be monofunctional monomers. In other words, when the ink composition of the present invention contains a polyfunctional monomer, the content thereof is less than 10% by mass, preferably less than 5% by mass, based on the total amount of polymerizable monomers. When the ratio of the monofunctional monomer to the total amount of the polymerizable monomer is less than 90% by mass, sufficient flexibility cannot be imparted to the resulting ink composition, resulting in an ink composition having poor stretchability, and various Adhesion to the surface of the recording medium made of the material is also reduced. Here, the amount of the monofunctional monomer means the total amount of the aromatic cyclic structure monofunctional monomer, the alicyclic structure monofunctional monomer, and the monofunctional monomer having a structure other than the above two types.

  The content of the polymerizable monomer contained in the ink composition of the present invention is preferably 70 parts by mass or more and more preferably 80 parts by mass or more with respect to 100 parts by mass of the ink composition. Moreover, it is preferable that it is 95 mass parts or less, and it is more preferable that it is 90 mass parts or less. Moreover, when the ink composition of the present invention contains a polymerizable oligomer, the content thereof is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass of the ink composition. By containing the polymerizable oligomer in addition to the polymerizable monomer, excellent flexibility and stretchability can be imparted to the ink composition.

(Coloring material)
The ink composition of the present invention contains a colorant. As the coloring material used in the present invention, various conventionally known dyes can be used. From the viewpoint of weather resistance, it is preferable to use either or both of an inorganic pigment and an organic pigment.
Basically, a pigment having a cyan color, a pigment having a magenta color, a pigment having a yellow color, a black pigment, and a white pigment are used. In some cases, an image having excellent color reproducibility can be formed by using special color pigments such as violet, blue, green, orange and red. In addition to general black pigments and white pigments, and three primary color pigments of cyan, magenta and yellow, depending on the purpose, for example, metallic luster pigments such as gold and silver, colorless or light color extender pigments, etc. May be.

  Specific examples of the inorganic pigment include, for example, titanium oxide, zinc white, zinc oxide, tripone, iron oxide, aluminum oxide, silicon dioxide, kaolinite, montmorillonite, talc, barium sulfate, calcium carbonate, silica, alumina, cadmium. Red, Red, Molybdenum Red, Chrome Vermillion, Molybdate Orange, Yellow Lead, Chrome Yellow, Cadmium Yellow, Yellow Iron Oxide, Titanium Yellow, Chrome Oxide, Pyridian, Cobalt Green, Titanium Cobalt Green, Cobalt Chrome Green, Ultramarine Blue, Ultra Examples include marine blue, bitumen, cobalt blue, cerulean blue, manganese violet, cobalt violet, and mica.

  Specific examples of organic pigments include azo, azomethine, polyazo, phthalocyanine, quinacridone, anthraquinone, indigo, thioindigo, quinophthalone, benzimidazolone, and isoindoline organic pigments. Etc. Carbon black made of acidic, neutral or basic carbon may be used. Further, crosslinked hollow particles of acrylic resin or the like may be used as the organic pigment.

  Specific examples of the pigment having a cyan color include C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. And CI Pigment Blue 60. Among these, from the viewpoint of weather resistance and coloring power, C.I. I. Pigment blue 15: 3, C.I. I. Either or both of Pigment Blue 15: 4 are preferred.

  Specific examples of pigments having a magenta color include C.I. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 168, C.I. I. Pigment red 184, C.I. I. Pigment red 202, C.I. I. Pigment red 209, C.I. I. Pigment red 254, C.I. I. Pigment violet 19 and the like. Among these, from the viewpoint of weather resistance and coloring power, C.I. I. Pigment red 122, C.I. I. Pigment red 202, C.I. I. Pigment red 209, C.I. I. Pigment red 254, and C.I. I. At least one selected from the group consisting of CI Pigment Violet 19 is preferred.

  Specific examples of the pigment having a yellow color include C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14C, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 130, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 139, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 213, C.I. I. And CI Pigment Yellow 214. Among these, from the viewpoint of weather resistance, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 139, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 213, and C.I. I. At least one selected from the group consisting of CI Pigment Yellow 214 is preferred.

  Specific examples of the black pigment include, for example, HCF, MCF, RCF, LFF, and SCF manufactured by Mitsubishi Chemical Corporation; Monarch and Legal manufactured by Cabot; Color black, special black, and printtex manufactured by Degussa Huls; Examples include Toka Black manufactured by Tokai Carbon; Raven manufactured by Columbia, and the like. Among these, HCF # 2650, HCF # 2600, HCF # 2350, HCF # 2300, MCF # 1000, MCF # 980, MCF # 970, MCF # 960, MCF88, LFFMA7, MA8, MA11, MA77 manufactured by Mitsubishi Chemical Corporation MA100 and Degussa Huls, Printex 95, Printex 85, Printex 75, Printex 55, Printex 45, and at least one selected from the group consisting of Printex 45 are preferable.

Examples of white pigments include Pigment White 6, 18, and 21. Specific examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white). ), Strontium titanate (SrTiO ₃ , so-called titanium strontium white), and the like can be used. Titanium oxide has a lower specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so it has a high hiding power and coloring power as a pigment, and it also has acid, alkali, and other environments. Excellent durability against. Therefore, it is preferable to use titanium oxide as the white pigment. Other white pigments (may be other than the listed white pigments) may be used as necessary.

  The content of the colorant in the ink composition may be appropriately selected depending on the color and purpose of use, but is generally preferably 0.1 parts by mass or more with respect to 100 parts by mass of the ink composition, The amount is more preferably 0.3 parts by mass or more, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. When the content of the colorant is within the above range, the fluidity is maintained without increasing the viscosity of the ink composition, and the ink composition of the present invention having excellent image coloring power can be obtained.

When a pigment is used as the coloring material, a pigment derivative or a pigment dispersant may be further used to improve the dispersibility of the pigment. Specific examples of the pigment derivative include a pigment derivative having a dialkylaminoalkyl group and a pigment derivative having a dialkylaminoalkylsulfonic acid amide group. Specific examples of the pigment dispersant include ionic or nonionic surfactants and anionic, cationic or nonionic polymer compounds. Among these, a polymer compound containing a cationic group or an anionic group is preferable from the viewpoint of dispersion stability. Examples of commercially available pigment dispersants include SOLSPERS manufactured by Lubrizol, DISPERBYK manufactured by BYK Chemie, EFKA manufactured by Fuka Additives, and the like.
The contents of the pigment derivative and the pigment dispersant in the ink composition are each preferably 0.05 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the ink composition.

(Photopolymerization initiator)
The ink composition of the present invention preferably contains a photopolymerization initiator in order to initiate polymerization by a low energy irradiation means. Examples of the photopolymerization initiator that can be contained in the ink composition of the present invention include acylphosphine oxide initiators, α-aminoalkylphenone initiators and thioxanthone initiators, arylalkyl ketone initiators, and oxime ketone initiators. , Acylphosphonate initiators, thiobenzoic acid S-phenyl initiators, titanocene initiators, aromatic ketone initiators, benzyl initiators, quinone derivative initiators, ketocoumarin initiators, and the like. Among these, it is preferable to contain at least one photopolymerization initiator selected from the group consisting of acylphosphine oxide initiators, α-aminoalkylphenone initiators, and thioxanthone initiators. By using such a photopolymerization initiator, sufficient curability can be imparted. In particular, it is preferable to use an α-aminoalkylphenone-based initiator and a thioxanthone-based initiator together because they are less susceptible to oxygen inhibition and can obtain a more sufficient curing rate.

  Specific examples of the acylphosphine oxide initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2, 3,5,6-tetramethylbenzoyldiphenylphosphine oxide, 2,6-dimethylbenzoyldiphenylphosphine oxide, 4-methylbenzoyldiphenylphosphine oxide, 4-ethylbenzoyldiphenylphosphine oxide, 4-isopropylbenzoyldiphenylphosphine oxide, 1-methyl Cyclohexanoylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2,4,6-trimethylbenzoylphenylphosphinic acid isopropyl ester, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide Etc. These may be used alone or in combination. Moreover, as an acyl phosphine oxide type | system | group initiator available on the market, DAROCURE TPO made from BASF is mentioned, for example.

  Specific examples of the α-aminoalkylphenone initiator include 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino- Examples include 1- (4-morpholinophenyl) butanone-1, 2-methyl-1- [4- (methoxythio) -phenyl] -2-morpholinopropan-2-one. These may be used alone or in combination. Examples of the α-aminoalkylphenone initiator available on the market include IRGACURE 369 and IRGACURE 907 manufactured by BASF.

  Specific examples of the thioxanthone initiator include thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2, Examples include 4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propoxythioxanthone. These may be used alone or in combination. Examples of thioxanthone initiators available on the market include KAYACURE DETX-S manufactured by Nippon Kayaku Co., and Chivacure ITX manufactured by Double Bond Chemical.

The content of the photopolymerization initiator in the ink composition is preferably 2 parts by mass or more, more preferably 5 parts by mass with respect to 100 parts by mass of the ink composition, although it depends on the content and type of the polymerizable compound. It is above, Preferably it is 30 mass parts or less, More preferably, it is 20 mass parts or less. When the content of the photopolymerization initiator is in the above range, sufficient curability can be imparted to the ink composition, and the ink composition can be prevented from being precipitated at a low temperature.
Further, when an α-aminoalkylphenone initiator and a thioxanthone initiator are used in combination as a photopolymerization initiator, the ratio is as follows with respect to the total amount of the α-aminoalkylphenone initiator and the thioxanthone initiator: It is preferable that it exists in the range.
α-aminoalkylphenone initiator: 40 to 99%
Thioxanthone initiator: 1 to 60%

  When the ink composition of the present invention contains a photopolymerization initiator other than an acylphosphine oxide initiator, an α-aminoalkylphenone initiator, and a thioxanthone initiator as a photopolymerization initiator, The content of the polymerization initiator is preferably 5 parts by mass or less in total with respect to 100 parts by mass of the ink composition. If the content of the other photopolymerization initiator is too large, the reactivity may decrease.

(Surface conditioner)
The ink composition of the present invention preferably contains a surface conditioner for the purpose of improving wettability to the surface of the recording medium and preventing repelling. In the present specification, the “surface adjusting agent” means a substance having a hydrophilic part and a hydrophobic part in the molecular structure and capable of adjusting the surface tension of the ink composition by adding.

  Specific examples of the surface conditioner that can be contained in the ink composition of the present invention include anionic surface conditioners such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxy Nonionic surface conditioners such as ethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, cationic surface conditioners such as alkylamine salts and quaternary ammonium salts, silicone surface conditioners And a fluorine-based surface conditioner. These surface conditioners can be used alone or in combination of two or more.

  The content of the surface conditioner in the ink composition of the present invention can be appropriately selected depending on the purpose of use. For example, the total amount is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the ink composition. The amount is more preferably 0.05 parts by mass or more, more preferably 5 parts by mass or less, and even more preferably 2.5 parts by mass or less. If the amount of the surface conditioner is too large, undissolved material may be produced or foaming may be caused.

[Anti-gelling agent]
The ink composition of the present invention preferably contains an anti-gelling agent. Storage stability can be improved by containing an antigelling agent. Moreover, it is preferable to add an antigelling agent from the viewpoint of preventing head clogging due to polymerization of the polymerizable compound by thermal energy.

Examples of the anti-gelling agent include hydroquinone, benzoquinone, p-methoxyphenol, hydroquinone monomethyl ether, hydroquinone monobutyl ether, TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl), and TEMPOL (4-hydroxy). -2,2,6,6-tetramethylpiperidineoxyl), cuperone Al and the like. Examples of commercially available products include IRGASTAB UV-10, IRGASTAB UV-22, and FIRSTCURE ST-1 (manufactured by ALBEMARLE). These anti-gelling agents can be used alone or in combination.

  The content of the anti-gelling agent in the ink composition of the present invention is preferably 0.001 part by mass or more and more preferably 0.01 part by mass or more with respect to 100 parts by mass of the ink composition. Moreover, it is preferable that it is 5 mass parts or less, and it is more preferable that it is 1 mass part or less.

The ink composition of the present invention may contain a sensitizing dye as a sensitizer. By containing a sensitizer, the sensitivity of the photopolymerization initiator can be improved. Examples of preferred sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region. For example, polynuclear aromatics, xanthenes, cyanines, merocyanines, thiazines, acridines, anthraquinones, coumarins and the like are preferable.
Furthermore, as the co-sensitizer, a known compound having an action such as further improving sensitivity or suppressing polymerization inhibition by oxygen can be used. Examples thereof include amines, and specific examples include triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

  When the ink composition of the present invention uses a non-permeable or slowly penetrable recording medium from the viewpoint of stability over time such as non-uniformity with time, liquid turbidity due to dye precipitation, etc. From the viewpoint of drying properties, water is not substantially contained.

In the ink composition of the present invention, for example, for the purpose of improving the polarity and viscosity of the ink composition, the surface tension, the solubility and dispersibility of the coloring material, adjusting the conductivity, and adjusting the printing performance, a solvent is used. Can be contained. The solvent is not particularly limited as long as it is compatible with the components constituting the ink composition of the present invention, particularly the polymerizable monomer, and a known solvent can be used.
For example, an alcohol solvent, a ketone solvent, an ester solvent, an ether solvent, a hydrocarbon solvent, and the like can be given. Specifically, methanol, 2-butanol, acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, and the like can be used. These solvents may be used alone or in combination of two or more.

When the ink composition of the present invention contains a solvent, the content of the solvent is preferably 10 parts by mass or less, preferably 1 part by mass or less, with respect to 100 parts by mass of the ink composition. The lower limit is not particularly limited. The ink composition of the present invention preferably contains substantially no solvent.
Note that “substantially free” means that water or a solvent is unavoidably mixed, for example, water or a solvent contained in a raw material or a raw material used for cleaning a production facility in the production process is unavoidable. It means not to exclude the case of mixing.

If necessary, the ink composition of the present invention may further contain a storage stabilizer, conductive salts and other additives as optional components. Examples of other additives that can be used include known additives such as polymers, ultraviolet absorbers, antioxidants, anti-fading agents, and pH adjusters.
As for the ultraviolet absorber, antioxidant, fading inhibitor, and pH adjuster, known compounds may be appropriately selected and used. Specifically, for example, addition described in JP-A-2001-181549 An agent or the like can be used.

  As a method for preparing the ink composition of the present invention, a conventionally known preparation method can be used. Specifically, for example, a mixture is prepared by premixing a pigment, a part or all of a polymerizable monomer (polymerizable oligomer in the case of blending), and, if necessary, a pigment dispersant. To prepare a primary dispersion. Examples of the disperser include a disperser; a container drive medium mill such as a ball mill, a centrifugal mill, and a planetary ball mill; a high-speed rotating mill such as a sand mill; and a medium agitation mill such as a stirring tank mill.

  Next, the remaining polymerizable compound, the polymerization initiator and the surface conditioner, and other additives such as an anti-gelling agent as necessary are added to the primary dispersion and mixed uniformly using a stirrer. Specific examples of the stirrer include a three-one motor, a magnetic stirrer, a disperser, and a homogenizer. Further, the ink composition may be mixed using a mixer such as a line mixer. Furthermore, the ink composition may be mixed using a disperser such as a bead mill or a high-pressure jet mill for the purpose of further reducing the particles in the ink composition.

  In order to stably discharge onto the surface of the recording medium by the ink jet method, the viscosity at 25 ° C. of the ink composition of the present invention is preferably about 3 mPa · s to 35 mPa · s. The viscosity of the ink composition can be measured using a rotary viscometer.

  In addition, from the viewpoint of preventing the ink composition from spreading and repelling on the surface of the recording medium, and from the viewpoint of ensuring stable continuous ejection, the surface tension of the ink composition of the present invention is about 25 to 33 mN / m. Preferably there is. If the surface tension of the ink composition is less than 25 mN / m, the surface of the recording medium is likely to be repelled, and there is a possibility that an image cannot be drawn. The ink composition tends to spread on the surface, and the image may be blurred. In addition, if the above range is greatly deviated, the ink may be out of the IJP suitability, and the ink itself may cause ejection failure.

  The ink composition of the present invention is very excellent in stretchability after curing. For example, when the printed film is stretched after printing on an olefin-based film (for example, SPM100: manufactured by Nihon Matai Co., Ltd.), it is at least 700%. Has elongation. For this reason, for example, a printing film such as a marking film (car wrapping film used for decoration of vehicles, etc.) is printed and the printed film is stretched together with the surface of the recording medium, or a printed matter such as a three-dimensional stereoscopic display member is formed in three dimensions. It is suitable for.

Accordingly, in a preferred embodiment of the present invention, the ink composition of the present invention is used as an image forming ink. In particular, the ink composition of the present invention can be suitably used as an image-forming ink in applications that require a large stretchability or in applications such as overcoat or lamination.
In this embodiment, the ink composition of the present invention may be directly applied to the surface of the recording medium by an ink jet method.

  Further, the ink composition of the present invention has excellent adhesion to recording media of various materials such as a non-permeable recording medium. Therefore, for example, when printing is performed using a general inkjet ink composition having relatively low adhesion to a non-permeable recording medium, the ink composition of the present invention can be used as a primer ink. .

When the ink composition of the present invention is used as a primer ink, for example, a primer layer is formed by applying the ink composition of the present invention on a recording medium by an inkjet method, and at the same time or immediately after that, on the primer layer. An image can be formed by discharging an ink composition for image formation that is cured by irradiation with energy rays and curing the ink composition with energy rays.
In particular, since the ink composition of the present invention can be applied by an ink jet method, when the ink composition of the present invention is used as a primer ink, at least one ink case constituting an ink set is filled with the ink composition of the present invention. The printing process by the multi-pass method can be performed, and the primer layer and the image can be formed in a series of processes. Of course, the ink composition of the present invention may be applied to the recording medium in advance by using a separate coating apparatus, and then image formation may be performed with the image forming ink.

  When the ink composition of the present invention is used as a primer ink, the image forming ink used for forming an image on the primer formed by the primer ink of the present invention is not particularly limited, and a conventional inkjet method A known ink composition used in the above can be used, but it is preferable to use an ink composition containing an energy ray-curable polymerizable compound and using a pigment as a coloring material.

In particular, in the case where a strength higher than the strength of the surface of the printed coating obtained when the ink composition of the present invention is used as an image forming ink is required, the ink jet method is used on the recording medium. A primer layer is formed by applying an ink composition, and then various images are formed by using an image forming ink having high surface hardness after curing and excellent chemical resistance and scratch resistance. It is possible to obtain a printed matter having excellent adhesion to a recording medium made of the above material and having high printing surface strength.
Hereinafter, in order to obtain the above effect, an image forming ink composition particularly suitable for use with the ink composition of the present invention as a primer ink will be described.

  The image forming ink composition is configured to be at least a composition for forming an image. Specifically, for example, it contains at least one kind of polymerizable compound and, if necessary, is composed of a polymerization initiator, a colorant, a surface conditioner, an antigelling agent, other additives, and the like.

As the polymerizable compound, for example, a polymerizable compound such as a polymerizable monomer exemplified as one that can be used in the ink composition of the present invention can be appropriately selected and used.
As the polymerizable compound used in the image forming ink composition, a (meth) acrylate compound and a (meth) acrylamide compound are preferable from the viewpoint of curing speed. In particular, it is preferable to mainly use a polyfunctional polymerizable compound, and it is preferable to contain a tetrafunctional or higher functional (meth) acrylate. Furthermore, from the viewpoint of reducing the viscosity of the ink composition for image formation and improving the adhesion, trifunctional or higher polyfunctional (meth) acrylate and monofunctional (meth) acrylate or bifunctional (meth) acrylate or (meth) It is preferable to use acrylamide together.

In the image forming ink composition, the mixing ratio of the monofunctional polymerizable compound to the polyfunctional polymerizable compound is 9: 1 to 1: 9 in terms of mass ratio (monofunctional polymerizable compound: polyfunctional polymerizable compound). It is preferably 8: 2 to 2: 8, more preferably 4: 6 to 2: 8. When the mixing ratio of the monofunctional polymerizable compound and the polyfunctional polymerizable compound is within the above numerical range, an image forming ink composition having an appropriate curing speed and viscosity and capable of realizing excellent surface hardness is obtained. be able to.
The content of the polymerizable compound is preferably 50 to 99.6% by mass, and preferably 60 to 99.0% by mass, based on the solid content (mass) of the image forming ink composition.

  As a polymerization initiator, the photoinitiator illustrated as what can be used for the ink composition of this invention, for example can be selected suitably, and can be used. Specifically, from the viewpoint of curability, aromatic ketones are preferable, compounds having a benzophenone skeleton or a thioxanthone skeleton are more preferable, and α-aminoalkylphenone compounds and acylphosphine oxide compounds are particularly preferable. A polymerization initiator can be used individually or in combination of 2 or more types. Moreover, it can also use together with a well-known sensitizer for the purpose of a sensitivity improvement.

  The polymerization initiator is preferably selected and contained as long as the storage stability of the image forming ink composition can be maintained to a desired level. The content is, for example, preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass with respect to the solid content of the image forming ink composition. Further, the content ratio of the polymerization initiator and the polymerizable compound is preferably 0.5: 100 to 30: 100 in terms of mass ratio (polymerization initiator: polymerizable compound), and 1: 100 to 15: 100. It is more preferable that

  The ink composition for image formation includes colorants, surface conditioners, anti-gelling agents, sensitizers, co-sensitizers, storage stabilizers, conductive salts, solvents, other additives, and the like depending on the purpose. May be included. As these components, each component illustrated as what can be used for the ink composition of this invention can be selected suitably, and can be used.

The ink composition of the present invention can be used for recording media of various materials and exhibits good adhesion to the surface of recording media of various materials.
As the recording medium, any of a permeable recording medium, a non-permeable recording medium, and a slowly permeable recording medium can be used.

  Among others, the effect of the present invention is more remarkably exhibited in non-permeable and slowly permeable recording media. Here, in this specification, the “penetrable recording medium” means, for example, a time required for the entire liquid amount to permeate when an ink droplet of 10 pL (picoliter) is dropped on the surface of the recording medium. A recording medium having a millisecond or less is referred to. “Non-permeable recording medium” refers to a recording medium in which liquid droplets do not substantially permeate. Note that “substantially does not permeate” specifically means that, for example, the ink penetration rate of a droplet after dropping an ink droplet on the surface of a recording medium is 5% or less. The “slowly permeable recording medium” refers to a recording medium in which the time until the entire liquid amount permeates is 100 milliseconds or more when a 10 pL ink droplet is dropped on the surface of the recording medium. Say.

  Examples of the permeable recording medium include plain paper, porous paper, and other recording media that can absorb ink droplets. Examples of the non-permeable or slowly permeable recording medium include art paper, synthetic resin, rubber, resin-coated paper, glass, metal, earthenware, and wood. In the present invention, for the purpose of adding a function, a recording medium in which a plurality of these materials are combined and combined can be used.

  Synthetic resins include, for example, polyesters such as polyethylene terephthalate and polybutadiene terephthalate, polyolefins such as polyvinyl chloride, polystyrene, polyethylene, polyurethane, and polypropylene, acrylic resins, polycarbonate, acrylonitrile-butadiene-styrene copolymers, diacetates, and triacetates. , Polyimide, cellophane, celluloid and the like.

The thickness and shape of the recording medium when a synthetic resin is used are not particularly limited, and may be any of a film shape, a card shape, and a block shape, and may be either transparent or opaque. .
As a usage form of the synthetic resin, it is also preferable to use it in the form of a film used for so-called soft packaging, and various non-absorbable plastics and films thereof can be used. Examples of the plastic film include PET film, OPS film, OPP film, PNY film, PVC film, PE film, TAC film, and PP film. Other plastics that can be used include polycarbonate, acrylic resin, ABS, polyacetal, PVA, and rubbers.

  Examples of the resin-coated paper include a transparent polyester film, an opaque polyester film, an opaque polyolefin resin film, and a paper support in which both surfaces of paper are laminated with a polyolefin resin.

  Examples of the metal include aluminum, iron, gold, silver, copper, nickel, titanium, chromium, molybdenum, silicon, lead, zinc, and stainless steel, and composite materials thereof.

  The recording medium that can exhibit the effect of the ink composition of the present invention is a recording medium that is not particularly permeable, such as an OPP film, a CPP film, PE, PET, PP, a metal plate, a soft bag with low permeability. Materials, laminated paper, coated paper, art paper, and the like.

  The inkjet method is not particularly limited, but is a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electrical signal. An acoustic ink jet method using a radiation pressure that irradiates the ink by changing the sound beam into an acoustic beam, and a thermal ink jet method using the pressure generated by heating the ink to form bubbles. The ink jet method includes a method of ejecting a large number of low-density inks called photo inks in a minute volume, a method of improving image quality using a plurality of inks having substantially the same hue and different densities, and colorless and transparent inks. The method using is included.

  In the present invention, energy application for initiating the polymerization reaction of the polymerizable compound can be performed by irradiation with a conventionally known energy beam. As the irradiation means, an ultraviolet LED, an ultraviolet laser, or the like can be used in addition to a mercury lamp or a metal halide lamp. The energy rays are preferably applied to the ink composition after 1 to 1,000 milliseconds have elapsed after the ink composition is discharged onto the surface of the recording medium. If the elapsed time is less than 1 millisecond, the distance between the head and the light source is too short, and the head may be irradiated with energy rays, leading to an unexpected situation. On the other hand, if the elapsed time exceeds 1,000 milliseconds, the image quality tends to deteriorate due to ink bleeding when multiple colors are used.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following, “part” means “part by mass”.

  The component composition of the ink composition used in each example and comparative example is shown in Table 1 below.

[Preparation of ink composition]
Example 1: Ink composition The formulation shown in Table 2 contains the colorant (MA-8), dispersant (Sol. 33000), and polymerizable compound (HPPA, IBOA, IOA) shown in Table 2 in a 100 ml plastic bottle. The mixture was weighed in an amount, 100 parts of zirconia beads having a diameter of 0.1 mm were added thereto, and this mixture was subjected to a dispersion treatment for 2 hours with a paint conditioner (manufactured by Toyo Seiki Co., Ltd.) to obtain a primary dispersion. Next, a photopolymerization initiator (IRGACURE907, ChivacureITX), a surface conditioner (Tegorad 2100), and an anti-gelling agent (H-TEMPO) were added to the obtained primary dispersion in the amounts shown in Table 2, and magnetic. The mixture was stirred for 30 minutes with a stirrer. After stirring, the mixture was suction filtered using a glass filter (manufactured by Kiriyama Seisakusho) to prepare an ink composition.

Examples 2-18 and Comparative Examples 1-4
Ink compositions were prepared in the same manner as in Example 1 so that the compositions shown in Table 2 were obtained.

  The viscosity and surface tension of each ink composition of Examples and Comparative Examples prepared as described above were measured by the following methods. The results are shown in Table 3.

〔viscosity〕
Using an R100 viscometer (manufactured by Toki Sangyo Co., Ltd.), the viscosity was measured under the conditions of 25 ° C. and cone rotation speed of 10 rpm.

〔surface tension〕
The surface tension at 25 ° C. was measured using a fully automatic balance type electro surface tension meter ESB-V (manufactured by Kyowa Kagaku).

1. Evaluation as image forming ink The following four types of recording media were used, and the ink compositions of Examples 1 to 18 and Comparative Examples 1 to 4 were applied to the surface of each recording medium, and the adhesion was evaluated. The results are shown in Table 3.
[Recording medium]
Glass: MICRO SLIDEGLASS S9112 made by MATSUNAMI
Tile: KEL-GEF made by INAX
Acrylic plate: Kuraray Trading Co. (thickness 1.0mm)
Copper plate: HC336 manufactured by Hikari Co., Ltd.

Using the following film as a recording medium, the ink compositions of Examples 1 to 18 and Comparative Examples 1 to 4 were applied to the surface of each recording medium, the elongation was measured, and the stretchability of each ink composition was evaluated. . The results are shown in Table 3.
[Recording medium]
Media for stretching test: SPM100 (olefin film) manufactured by Nippon Matai

(Image forming method)
In the procedure described below, each ink composition was applied on each recording medium to form an image, and a printed matter was obtained.

(A) An ink solid print was produced on a recording medium using an ink jet recording apparatus provided with a piezo ink jet nozzle, and an ink layer having a film thickness of 3 μm was formed. This ink jet recording apparatus includes an ink tank, a supply pipe, a front chamber ink tank immediately before the head, and a piezo head as an ink supply system. In addition, the ink jet recording apparatus was driven at a driving frequency of 10 KHz so that ink could be ejected with a droplet size of about 7 pL and a resolution of 600 × 600 dpi.
(B) An ultraviolet LED (“NLBU21W01-E2” manufactured by Nichia Corporation) is used as an irradiating means on the ink layer, and the ink layer is irradiated with ultraviolet rays so that the total irradiation light amount is 300 mJ / cm ^2. The layer was cured.

  Each print was evaluated for its characteristics by the following method. The results are shown in Table 3.

[Adhesion evaluation method]
Evaluation was performed according to “cross cut test tape (registered trademark) peeling” defined in JIS K5600-5-6. The evaluation criteria were as follows.
○: 10 or less peeled parts in cross cut test Δ: 11 to 20 peeled parts in cross cut test ×: 21 or more peeled parts in cross cut test

(Measurement of elongation)
A printed image was formed on the stretching test medium by the procedures (A) and (B). The obtained printed matter was cut into a 10 mm × 70 mm strip shape to obtain a test piece.
The positions of 10 mm on both sides of the test piece were fixed to the sample stage, and evaluated using a tensile tester: AUTOGRAGH AGS-H 100N manufactured by SIMADZU, at a pulling speed of 10 mm / min. When cracks occurred in the printed part of the test piece, the tension was stopped and the elongation rate was determined. The evaluation criteria were as follows. The results are shown in Table 3.
A: The film broke when it was stretched to 700%. There were no cracks or the like in the printed portion other than the broken portion of the film.
○: Elongation rate 200% or more and less than 700% ×: Elongation rate 200% or less

  It was confirmed that each of the ink compositions of Examples 1 to 18 has excellent adhesion to glass, tile, acrylic plate and copper plate. It was also confirmed that a high elongation was achieved when an image was formed on an olefin film.

2. Evaluation as primer ink [Preparation of ink composition for forming image layer]
In a 100 ml plastic bottle, the colorant, dispersant and polymerizable compound are weighed in the amounts shown in Table 4, 100 parts of zirconia beads having a diameter of 0.1 mm are added thereto, and this mixture is added to a paint conditioner (manufactured by Toyo Seiki Co., Ltd.). ) For 2 hours to obtain a primary dispersion. Next, a photopolymerization initiator, a surface conditioner, and an antigelling agent were added to the obtained primary dispersion in the amounts shown in Table 4, and the mixture was stirred for 30 minutes with a magnetic stirrer. After stirring, this mixture was suction filtered using a glass filter (manufactured by Kiriyama Seisakusho) to prepare image forming ink compositions P-1 to P-5.

(Image forming method)
The ink composition of Example 1 was applied to each recording medium of glass, tile, acrylic plate and copper plate according to the procedure described in (A) above, and the ink composition applied by the procedure described in (B) above. The product was cured to form a primer layer. Thereafter, an image was formed on the primer layer using the image forming ink P-1 according to the procedure described in the above (A) and (B) to obtain a printed matter. Similarly, an image was formed using each of the image forming inks (P-2 to P-5) to obtain a printed matter.
Further, with respect to the ink composition of Example 5, an image was formed with each image forming ink in the same manner as in the above method, and a printed matter was obtained.

  Adhesiveness was evaluated about the obtained printing surface. The evaluation was performed by the same method as the evaluation method in the above-described image forming ink composition. The results with the ink composition of Example 1 are shown in Table 5, and the results with the ink composition of Example 5 are shown in Table 6.

  When the ink composition of the present invention was used as a primer ink, it was confirmed that excellent adhesion was exhibited with respect to any of glass, tile, acrylic plate and copper plate.

  According to the present invention, there is provided an energy ray curable inkjet ink composition that has high adhesion to the surface of a recording medium made of various materials and realizes excellent stretchability that has not been achieved after curing. be able to.

Claims (8)

  An energy beam curable inkjet ink composition comprising a colorant and a polymerizable monomer, wherein the polymerizable monomer is a monofunctional monomer having an aromatic hydrocarbon ring structure in the molecule and an aliphatic carbonization in the molecule. An energy ray curable inkjet ink composition comprising a monofunctional monomer having a hydrogen-based cyclic structure, wherein 90% by mass or more of the polymerizable monomer is a monofunctional monomer.   The energy ray-curable inkjet ink composition according to claim 1, wherein the monofunctional monomer having an aromatic hydrocarbon-based cyclic structure includes 2-hydroxy-3-phenoxypropyl acrylate.   The monofunctional monomer having an aliphatic hydrocarbon ring structure includes isobornyl acrylate, cyclohexyl acrylate, 3,5,5-trimethylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate. The energy ray-curable ink-jet ink composition according to claim 1 or 2, which contains at least one selected from the group consisting of dicyclopentanyl acrylate.   The monofunctional monomer having an aromatic hydrocarbon ring structure and the monofunctional monomer having an aliphatic hydrocarbon ring structure in a mass ratio of 1:10 to 10: 1. The energy beam curable inkjet ink composition described.   The energy ray curable inkjet ink composition according to any one of claims 1 to 4, comprising 2-hydroxy-3-phenoxypropyl acrylate and isobornyl acrylate as the polymerizable monomer.   The energy beam according to any one of claims 1 to 5, comprising at least one photopolymerization initiator selected from the group consisting of a thioxanthone-based initiator, an acylphosphine oxide-based initiator, and an α-aminoalkylphenone-based initiator. A curable inkjet ink composition.   The energy ray-curable inkjet ink composition according to claim 1, which is used as an image forming ink.   The energy ray-curable inkjet ink composition according to any one of claims 1 to 6, which is used as a primer ink.