Active energy ray curable ink composition for ink jet printing

Abstract

The present invention addresses the problem of providing an active-energy-ray-curable inkjet printing ink composition in which the ink composition has low viscosity, no offensive odor, and excellent storage stability, discharge stability, and curing properties, and in which curing wrinkles do not occur during curing, and the cured coating film also has excellent bending resistance, abrasion resistance, and water resistance. As a solution to this problem, the present invention provides an active-energy-ray-curable inkjet ink composition that satisfies conditions A through D. A: The content of amine-modified oligomers is 1.0-20.0 mass% with respect to all the active-energy-ray-polymerizable components. B: The content of alkoxy-group-including (meth)acrylates is 2.0-20.0 mass% with respect to all the active-energy-ray-polymerizable components. C: The content of C10-20 alkyl-group-containing (meth)acrylates is 2.0-25.0 mass% with respect to all the active-energy-ray-polymerizable components. D: The content of at least one selected from the group consisting of 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, dipropylene glycol diacrylate, propoxylated (2) neopentyl glycol diacrylate, 1,10-decanediol diacrylate, and hydroxy pivalic acid neopentyl glycol diacrylate is 30.0-60.0 mass% with respect to all the active-energy-ray-polymerizable components.

Description

[Technical field]

[0001] The present invention relates to an actinic ray-curable ink composition for inkjet printing suitable for printing on substrates such as paper, capsules, gel, metal foil, glass, wood, and cloth, particularly on cardboard sheets, and to a printed matter obtained using the same. [Background technology]

[0002] As described in Patent Document 1, it is known that preventing the occurrence of curing wrinkles during curing of photocurable inkjet inks is an issue. In addition, an inkjet ink composition containing an amine-modified oligomer and a monomer having multiple (meth)acryloyl groups is also known, for example, as described in Patent Document 2. However, such an ink composition does not satisfy the requirements C and D of the present invention. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2007 / 074768 [Patent Document 2] International Publication No. 2017 / 073654 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide an actinic ray-curable ink composition for inkjet printing, which has a low viscosity, is odorless, has excellent storage stability, ejection stability and curing properties, does not produce curing wrinkles upon curing, and provides a cured coating film that is also excellent in bending resistance, abrasion resistance and water resistance. [Means for solving the problem]

[0005] As a result of intensive research into solving the above problems, the present inventors have found that the above problems can be solved by using a specific composition, and have thus completed the present invention. That is, the present invention is as follows. 1. An actinic ray-curable inkjet ink composition that satisfies the following requirements A to D. A: The content of the amine-modified oligomer is 1.0 to 20.0 mass % of the total active energy ray-polymerizable components. B: Contains 2.0 to 20.0% by mass of an alkoxy group-containing (meth)acrylate in the total active energy ray-polymerizable components. C: Contains 2.0 to 25.0% by mass of (meth)acrylate containing an alkyl group having 10 to 20 carbon atoms in the total active energy ray-polymerizable components. D: At least one selected from the group consisting of 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, dipropylene glycol diacrylate, propoxylated (2) neopentyl glycol diacrylate, 1,10-decanediol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate is contained in an amount of 30.0 to 60.0% by mass in all active energy ray-polymerizable components. 2. The actinic energy ray-curable ink composition for inkjet printing according to 1, wherein at least a part or all of requirement B is a polyfunctional alkoxy group-containing (meth)acrylate monomer, and the polyfunctional alkoxy group-containing (meth)acrylate monomer is contained in an amount of 5.0 to 20.0 mass % of all actinic energy ray-polymerizable components. 3.E: The actinic ray-curable ink composition for ink-jet printing according to 1 or 2, wherein the ink composition contains 5.0 to 30.0% by mass of a (meth)acrylic monomer having a hydroxyl group. 4.F: The actinic ray-curable ink composition for ink-jet printing according to any one of 1 to 3, which contains a photopolymerization initiator. 5. The actinic ray-curable ink composition for ink-jet printing according to any one of items 1 to 4, wherein at least a part of the (meth)acrylate containing an alkyl group having 10 to 20 carbon atoms in requirement C is lauryl acrylate and / or stearyl acrylate. 6.G: The actinic ray-curable ink composition for ink-jet printing according to any one of 1 to 5, further comprising a colorant. Effect of the Invention

[0006] The active energy ray-curable ink composition for inkjet printing of the present invention can exhibit the following effects: the ink composition has a low viscosity, is odorless, has excellent storage stability, ejection stability and curing properties, does not generate curing wrinkles upon curing, and the cured coating film has excellent bending resistance, abrasion resistance and water resistance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The actinic energy ray-curable ink composition for ink-jet printing of the present invention satisfies the above requirements A to D. The following will explain each requirement in turn. <Requirement A> Requirement A is that the content of the amine-modified oligomer is 1.0 to 20.0% by mass based on the total polymerizable components of the actinic energy ray-curable ink composition for ink-jet printing. Examples of the amine-modified oligomer include acrylated amine compounds such as CN371, CN373, CN383, and CN386 (manufactured by Sartomer Corporation), which are oligomers of acrylated amine compounds having two active energy ray-polymerizable functional groups and two amino groups in the molecule. If the content of the amine-modified oligomer in the actinic energy ray-curable ink composition for inkjet printing is less than 1.0% by mass, the surface curability and abrasion resistance will be poor. If it exceeds 20.0% by mass, the viscosity of the actinic energy ray-curable ink composition for inkjet printing will tend to increase, resulting in poor storage stability and abrasion resistance. The content of the amino group-containing oligomer in the total polymerizable components of the active energy ray-curable ink composition for inkjet printing is preferably 1.2% by mass or more, more preferably 1.4% by mass or more, even more preferably 1.6% by mass or more, most preferably 1.8% by mass or more, and extremely preferably 5.0% by mass or more. Also, it is preferably 17.0% by mass or less, more preferably 15.0% by mass or less.

[0008] <Requirement B> Requirement B is that the active energy ray-curable ink composition for ink-jet printing contains an alkoxy group-containing (meth)acrylate in an amount of 2.0 to 20.0 mass % of the total polymerizable components. The (meth)acrylate monomer having an alkoxy group is not particularly limited. For example, the (meth)acrylic monomer may be any monofunctional (meth)acrylate monomer, bifunctional (meth)acrylate monomer, trifunctional (meth)acrylate monomer, or polyfunctional acrylate monomer having 4 or more functional groups, each of which has little odor. In consideration of the environmental aspect, a (meth)acrylate monomer having an alkoxy group derived from biomass may be used. Specific examples of the alkoxyalkyl (meth)acrylate include monofunctional alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxybutyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 3-methoxybutyl (meth)acrylate, and 2-butoxyethyl (meth)acrylate; and polyalkylene glycol structure-containing monofunctional alkoxy group-containing (meth)acrylates such as 2-butoxydiethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, octoxypolyethylene glycol-polypropylene glycol mono(meth)acrylate, lauroxypolyethylene glycol mono(meth)acrylate, and stearoxypolyethylene glycol mono(meth)acrylate. Furthermore, polyfunctional alkoxy group-containing (meth)acrylates such as ethoxylated (3) trimethylolpropane tri(meth)acrylate and propoxylated (2) neopentyl glycol di(meth)acrylate can also be used. As the alkoxy group-containing (meth)acrylate which is the requirement B, the above-mentioned alkoxy group-containing polyfunctional (meth)acrylate is preferably contained in an amount of 30 to 100 mass % in requirement B. When the alkoxy group-containing polyfunctional (meth)acrylate is contained in this range, the abrasion resistance is excellent. In addition, it is preferable that the content of the alkoxy group-multifunctional (meth)acrylate monomer is 5.0 to 20.0% by mass in the total active energy ray-polymerizable components.

[0009] If the content of the alkoxy group-containing (meth)acrylate in the total active energy ray-polymerizable components is less than 2.0 mass %, bending resistance will be poor, and if it exceeds 20.0 mass %, water resistance will be poor. The content of the alkoxy group-containing (meth)acrylate in the total polymerizable components of the active energy ray-curable ink composition for inkjet printing is preferably 4.0% by mass or more, more preferably 8.0% by mass or more, even more preferably 10.0% by mass or more, and most preferably 11.0% by mass or more. Also, it is preferably 18.0% by mass or less, more preferably 16.0% by mass or less, even more preferably 14.0% by mass or less, and most preferably 13.0% by mass or less.

[0010] <Requirement C> As requirement C, the content of the (meth)acrylate containing an alkyl group having 10 to 20 carbon atoms may be 2.0 to 25.0 mass % in the total active energy ray-polymerizable component. The alkyl group having 10 to 20 carbon atoms may have any of a linear, branched, and alicyclic structure. Here, the (meth)acrylate containing an alkyl group having 10 to 20 carbon atoms is a monofunctional (meth)acrylate, and examples thereof include tridecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, isotetradecyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like.

[0011] If the content of the (meth)acrylate containing an alkyl group having 10 to 20 carbon atoms in the actinic energy ray-curable ink composition for inkjet printing is less than 2.0% by mass, the bending resistance will be poor, and if it exceeds 25.0% by mass, the abrasion resistance will be poor. The content of the (meth)acrylate containing an alkyl group having 10 to 20 carbon atoms in the total polymerizable components of the active energy ray-curable ink composition for inkjet printing is preferably 2.5% by mass or more, more preferably 3.0% by mass or more, even more preferably 3.5% by mass or more, and most preferably 4.0% by mass or more. Also, it is preferably 20.0% by mass or less, more preferably 18.0% by mass or less.

[0012] One of the raw materials of this alkyl group-containing (meth)acrylate having 10 to 20 carbon atoms is (meth)acrylic acid, and the other raw material is an alcohol having 10 to 20 carbon atoms. This alcohol can be obtained, for example, from a raw material derived from a plant, and has renewable carbon. The raw material derived from a plant is a plant raw material such as palm oil, palm kernel oil, coconut oil, etc. Since an alkyl group having 10 to 20 carbon atoms has a relatively large number of carbon atoms, the more (meth)acrylate made from this alkyl group as a raw material is used in an active energy ray-curable ink composition for inkjet printing, the more biomass-derived carbon can be used in the entire composition.

[0013] <Requirement D> Requirement D is that the content of at least one selected from 1,6-hexanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, propoxylated (2) neopentyl glycol diacrylate, 1,10-decanediol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate is 30.0 to 60.0 mass % of all polymerizable components in the active energy ray-curable ink composition for inkjet printing. If the content of requirement D in the actinic energy ray-curable ink composition for inkjet printing is less than 30.0 mass %, the curability and abrasion resistance will be poor, and if it exceeds 60.0 mass %, the bending resistance will be poor.

[0014] <Requirement E> Requirement E is that the content of the (meth)acrylic monomer having a hydroxyl group is 5.0 to 30.0 mass % of all polymerizable components in the active energy ray-curable ink composition for inkjet printing. However, the active energy ray-curable ink composition for inkjet printing may or may not contain the (meth)acrylic monomer having a hydroxyl group. As the (meth)acrylic monomer having a hydroxyl group, a (meth)acrylate monomer is preferable, and one or more of the following monomers can be used. Hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate; polyethylene glycol mono(meth)acrylates such as diethylene glycol monoethyl ether (meth)acrylate; glycol mono(meth)acrylates such as polypropylene glycol mono(meth)acrylate and 1,4-cyclohexanedimethanol mono(meth)acrylate; caprolactone-modified (meth)acrylates; hydroxyethylacrylamide; and EO (ethylene oxide)-modified succinic acid (meth)acrylate. In addition, (meth)acrylic monomers having a hydroxyl group such as 4-hydroxybutyl (meth)acrylate, which has little odor, are preferred.

[0015] In the present invention, the content of the (meth)acrylic monomer having a hydroxyl group in all polymerizable components in the active energy ray-curable ink composition for ink jet printing is preferably 7.0 mass % or more and preferably 25.0 mass % or less.

[0016] <Requirement H> Furthermore, as requirement H, a vinyl monomer can be contained. The vinyl monomer can be contained in an amount of 1.0 to 20.0 mass % of the total polymerizable components in the active energy ray curable ink composition for ink jet printing. By containing a vinyl monomer, when the ink composition is printed on a cardboard sheet or the like and the cardboard sheet or the like is folded, the folding resistance becomes better. However, the actinic energy ray-curable ink composition for ink-jet printing may or may not contain a vinyl monomer. The vinyl monomer is not particularly limited. Examples of the vinyl monomer include ethylene glycol divinyl ether, triethylene glycol divinyl ether, diethylene glycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, ethylene glycol monovinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, and trimethylolpropane trivinyl ether. Among these, the vinyl monomer is preferably triethylene glycol divinyl ether or the like, which has little odor.

[0017] <Compounds other than requirements A to E and H> In the present invention, in addition to the polymerizable components covered by requirements A to E and H, polymerizable compounds can be contained within a range in which performance is not deteriorated and odor is minimal. In the description of the compounds below, the (poly) before the polyol portion means a condensation product of mono-, di- or higher polyols. (Alkylene glycol di(meth)acrylate) (poly)alkylene glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-propanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,2-hexanediol di(meth)acrylate, and 1,5-hexanediol di(meth)acrylate, 2,5-Hexanediol di(meth)acrylate, 1,7-Heptanediol di(meth)acrylate, 1,8-Octanediol di(meth)acrylate, 1,2-Octanediol di(meth)acrylate, 1,9-Nonanediol di(meth)acrylate, 1,2-Decanediol di(meth)acrylate, 2-Methyl-2-Propyl-1,3-Propanediol di(meth)acrylate, 2,4-Dimethyl-2,4-Pentanediol di(meth)acrylate, 2,2-Diethyl-1,3-Propanediol di(meth)acrylate, 2,2,4-Trimethyl-1,3-Pentanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,2-dodecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,2-tetradecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, 1,2-hexadecanediol di(meth)acrylate, 2-methyl-2,4-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2-methyl-2-propyl-1,3-propanediol di(meth)acrylate, 2,4-dimethyl-2,4-pentane Diol di(meth)acrylate, 2,2-diethyl-1,3-propanediol di(meth)acrylate, 2,2,4-trimethyl-1,3-pentanediol di(meth)acrylate, dimethylol octane di(meth)acrylate, 2-ethyl-1,3-hexanediol di(meth)acrylate, 2,5-dimethyl-2,5-hexanediol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 2,4-diethyl-1,5-pentanediol di(meth)acrylate, Triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate,

[0018] ((Poly)glycerin poly(meth)acrylate) Glycerin di(meth)acrylate, glycerin tetra(meth)acrylate, diglycerin tetra(meth)acrylate, ((Poly)trimethylolpropane poly(meth)acrylate) Trimethylolpropane (meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane tetra(meth)acrylate, ditrimethylolpropane (meth)acrylate, ditrimethylolpropane di(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate,

[0019] ((Poly)pentaerythritol poly(meth)acrylate) pentaerythritol tetra(meth)acrylate and its ethylene oxide modified product, dipentaerythritol penta(meth)acrylate and its ethylene oxide modified product, dipentaerythritol hexa(meth)acrylate and its ethylene oxide modified product, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth)acrylate,

[0020] (Other polyacrylates) As polyhydric acrylates not included in the above, the following can be used. Monomers having 4 or more functional groups, such as pentaerythritol tetracaprolactonate tetra(meth)acrylate, ditrimethylolpropane tetracaprolactonate tetra(meth)acrylate, ditrimethylolbutane tetra(meth)acrylate, ditrimethylolhexane tetra(meth)acrylate, ditrimethyloloctane tetra(meth)acrylate, and tripentaerythritol polyalkylene oxide hepta(meth)acrylate. Hydroxypivalyl hydroxypivalate di(meth)acrylate, hydroxypivalyl hydroxypivalate dicaprolactonate di(meth)acrylate, dimethylol octane di(meth)acrylate, 2-ethyl-1,3-hexanediol di(meth)acrylate, 2,5-dimethyl-2,5-hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, and the like. Incidentally, 2-(2-vinyloxyethoxy)ethyl acrylate and methyl 2-(allyloxymethyl)acrylate may or may not be contained.

[0021] <Other polymerizable components> Examples of the polymerizable component that can be incorporated in the actinic ray-curable ink composition for ink-jet printing of the present invention include the following. Benzyl methacrylate, butyl (meth)acrylate, ethyl carbitol (meth)acrylate, caprolactone (meth)acrylate, methoxytripropylene glycol (meth)acrylate, phenoxyethyl (meth)acrylate, Other examples include acryloylmorpholine, acrylonitrile, acrylamide, diethylacrylamide, styrene, (meth)acrylic acid, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, pentaerythritol ethoxy tetraacrylate, caprolactam-modified dipentaerythritol hexaacrylate, ethoxylated bisphenol A diacrylate, alkoxylated tetrahydrofurfuryl acrylate, dimethylol-tricyclodecane di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, polytetramethylene glycol diacrylate, trimethylolpropane tri(meth)acrylate and its ethylene oxide modified product, and pentaerythritol tri(meth)acrylate. The amide group-containing monomer may or may not be contained.

[0022] <Requirement F> The actinic energy ray-curable ink composition for ink-jet printing of the present invention may contain a photopolymerization initiator. When an electron beam is used as the actinic energy ray, the ink composition may or may not contain a photopolymerization initiator. Examples of photopolymerization initiators that can be used include the following. Acylphosphine oxide polymerization initiators include bis-2,6-dimethoxybenzoyl-2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzyl-diphenylphosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819, or SB-PI719), and ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide (TPOL). The α-hydroxyketone polymerization initiators 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one (Irgacure 127), 2-hydroxy-4'-hydroxyethoxy-2-methylpropiophenone (Irgacure 2959), 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184), oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone} (ESACURE 185), ONE), 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-hydroxycyclohexyl phenyl ketone, bis[4-(2-hydroxy-2-methylpropanoyl)phenyl]ether (KIP160), etc.

[0023] Others include benzophenone, 4,4'-diethylaminobenzophenone, ethyl Michler's ketone, diethylthioxanthone, 2-methyl-1-(4-methylthio)phenyl-2-morpholinopropan-1-one, 4'-(methylthio)-α-morpholino-α-methylpropiophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 1-chloro-4-propoxythioxanthone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2,2-dimethyl-2-hydroxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-benzyl-2-dimethylamino-1-(morpholinophenyl)-butan-1-one, and polymer-type initiators (Omnipol TP, Omnipol BP), 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one (ESACURE1001M). Such photopolymerization initiators are commercially available and can be obtained under the trade names, for example, Irgacure 907, Irgacure 369, Irgacure 184, Irgacure 379, Irgacure 819, TPO, etc. A plurality of photopolymerization initiators may be used in combination.

[0024] Among them, it is preferable to use an acylphosphine oxide polymerization initiator in combination with an α-hydroxyketone polymerization initiator, and it is further preferable to use 2,4,6-trimethylbenzyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone} in combination. The acylphosphine oxide polymerization initiator and the α-hydroxyketone polymerization initiator can be mixed in a mass ratio of preferably acylphosphine oxide polymerization initiator:α-hydroxyketone polymerization initiator=8:1 to 2:1, more preferably 7:1 to 3:1. Furthermore, 2,4,6-trimethylbenzyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide can be blended in a mass ratio of preferably 2,4,6-trimethylbenzyl-diphenylphosphine oxide:bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide=2:3 to 10:1, more preferably 1:1 to 8:1. The thioxanthone-based photopolymerization initiator may not be contained.

[0025] In order to promote curing by ultraviolet light using a light-emitting diode (LED) as a light source, the active energy ray-curable ink composition for inkjet printing of this embodiment may further contain a photosensitizer (compound) that has light absorption characteristics mainly in the ultraviolet wavelength range of 400 nm or more and exhibits a sensitizing function for the curing reaction by light in that wavelength range. By using such a sensitizer, the ink composition of this embodiment can have enhanced LED curability.

[0026] The photosensitizer is an anthracene-based sensitizer, a thioxanthone-based sensitizer, or the like, and is preferably a thioxanthone-based sensitizer. The photosensitizers may be used in combination. Specifically, the photosensitizer is an anthracene-based sensitizer such as 9,10-dibutoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, or 9,10-bis(2-ethylhexyloxy)anthracene, or a thioxanthone-based sensitizer such as 2,4-diethylthioxanthone, 2-isopropylthioxanthone, or 4-isopropylthioxanthone. Representative examples of commercially available products include DBA and DEA (manufactured by Kawasaki Chemical Industries, Ltd.) as an anthracene-based sensitizer, and DETX, ITX, CPTX (manufactured by LAMBSON), Omnipol TX (manufactured by IGM), or the like as a thioxanthone-based sensitizer.

[0027] When a photosensitizer is included, the content of the photosensitizer in the ink composition is preferably more than 0 and not more than 5.0% by mass. If the content of the photosensitizer exceeds 5.0% by mass, the effect of blending the photosensitizer in the ink composition is unlikely to be improved, and there is a tendency for excessive addition.

[0028] When a thioxanthone-based sensitizer is contained as a photosensitizer, the active energy ray-curable ink composition for inkjet printing tends to turn yellow, resulting in a hue that is more yellowish than the color (original hue) based on a pigment or the like. Therefore, it is preferable to appropriately determine the content of the thioxanthone-based sensitizer for each color. Specifically, in the case of the white ink composition and the clear ink composition, which are susceptible to changes in color tone, it is preferable that the ink composition does not contain a thioxanthone-based sensitizer as a photosensitizer. In addition, in the case of the magenta ink composition and the cyan ink composition, since a vinylamide compound is used as a photopolymerizable compound, the cured coating film that has turned yellow tends to fade, and changes in hue are likely to become a problem. Therefore, it is preferable to use the photosensitizer within a range that does not cause problems in hue. In addition, in the case of the black ink composition and the yellow ink composition, since discoloration does not affect the hue easily and the photopolymerization is poorer than other hues, it is preferable to use a thioxanthone-based sensitizer in combination as a photopolymerization initiator.

[0029] It is also possible to use acrylic resins, vinyl chloride resins, vinyl chloride-vinyl acetate resins and ethylene-vinyl acetate resins, styrene-acrylic resins, styrene-maleic acid resins, rosin resins, rosin ester resins, petroleum resins, coumarone-indene resins, terpene phenol resins, phenol resins, ketone resins, urethane resins, melamine resins, urea resins, epoxy resins, cellulose resins, xylene resins, alkyd resins, aliphatic hydrocarbon resins, butyral resins, maleic acid resins, fumaric acid resins, and the like in combination, within a range in which the performance of the active energy ray-curable ink composition for ink jet printing of the present invention is not impaired.

[0030] <Requirement G> As the colorant contained in the active energy ray-curable ink composition for inkjet printing of the present invention, known pigments and dyes that have been conventionally used in active energy ray-curable ink compositions for inkjet printing can be used, and color pigments such as organic color pigments and inorganic color pigments are preferred. As a result, active energy ray-curable ink compositions for inkjet printing of each color can be obtained. Examples of organic coloring pigments include dye lake pigments, azo-based, benzimidazolone-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigo-based, thioindigo-based, perylene-based, perinone-based, diketopyrrolopyrrole-based, isoindolinone-based, nitro-based, nitroso-based, anthraquinone-based, flavanthrone-based, quinophthalone-based, pyranthrone-based, and indanthrone-based pigments. Inorganic color pigments include colored pigments such as titanium oxide, red ocher, antimony red, cadmium yellow, cobalt blue, ultramarine, Prussian blue, iron black, chromium oxide green, carbon black, and graphite (including achromatic color pigments such as white and black), and extender pigments such as calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc.

[0031] Specific examples of the representative hues of the above color pigments are as follows: Yellow pigments include CI Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 42, 73, 74, 75, 81, 83, 87, 93, 95, 97, 98, 108, 109, 114, 120, 128, 129, 138, 139, 150, 151, 155, 166, 180, 184, 185, 213, etc., and CI Pigment Yellow 150, 155, 180, 213, etc. are preferred. Magenta pigments include CI Pigment Red 5, 7, 12, 19, 22, 38, 48:1, 48:2, 48:4, 49:1, 53:1, 57, 57:1, 63:1, 101, 102, 112, 122, 123, 144, 146, 149, 168, 177, 178, 179, 180, 184, 185, 190, 202, 209, 224, 242, 254, 255, 270, CI Pigment Violet 19, and the like, and preferably CI Pigment Red 122, 202, CI Pigment Violet 19, and the like. Cyan pigments include CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 18, 22, 27, 29, 60, etc., and preferably CI Pigment Blue 15:4, etc. The black pigment is carbon black, such as CI Pigment Black 7. The white pigment is titanium oxide, aluminum oxide, or the like, and is preferably titanium oxide or the like that has been surface-treated with various materials such as alumina or silica. The content of the colorant in the ink composition is preferably 1% by mass or more, and preferably 20% by mass or less in the ink composition. When the content of the colorant is within the above range, the ink composition provides suitable image quality in the resulting printed matter and has excellent viscosity characteristics.

[0032] (Pigment dispersant)

[0113] Examples of pigment dispersants that may be contained in the active energy ray-curable ink composition for ink jet printing of the present invention when it contains a pigment include ionic or nonionic surfactants, and anionic, cationic or nonionic polymer compounds. Among these, polymeric compounds are preferred, such as the carbodiimide compounds described in JP2004-083872A, WO2003 / 076527A, and WO2004 / 000950A, and basic functional group-containing copolymers such as AJISPER PB821 and 822 (manufactured by Ajinomoto Fine-Techno Co., Ltd.), Solsperse 56000 (manufactured by Lubrizol Corp.), Solsperse 32000 (manufactured by Lubrizol Corp.), Solsperse 39000 (manufactured by Lubrizol Corp.), and DISPERBYK (manufactured by BYK Japan KK). These pigment dispersants can be used alone or in combination of two or more kinds. Among these, a copolymer containing a basic functional group having an amine value of 10 to 40 mgKOH / g is preferred. The pigment dispersant is appropriately selected depending on the type of pigment and the type of organic solvent used.

[0033] (Organic solvent) The actinic radiation-curable ink composition for ink-jet printing of the present invention may be a so-called solventless type in which all liquid components are solidified by a curing reaction, or a solvent type in which the coating film after printing is dried to remove the solvent and then cured, provided that water is not used as a solvent. The case where an organic solvent is contained in the actinic ray-curable ink composition for ink-jet printing of the present invention will be described below. The organic solvent that may be contained in the actinic ray-curable ink composition for ink-jet printing of the present invention is propylene carbonate, diethylene glycol dialkyl ether, dipropylene glycol alkyl ether acetate, or the like.

[0034] As the diethylene glycol dialkyl ether, it is preferable to use diethylene glycol ethyl methyl ether and / or diethylene glycol diethyl ether, and further, another diethylene glycol dialkyl ether can be used in combination. As the dipropylene glycol alkyl ether acetate, preferably an alkyl group having 6 or less carbon atoms, more preferably an alkyl group having 3 or less carbon atoms, and further preferably an alkyl group having 2 or less carbon atoms can be used.

[0035] In order to adjust the drying property and further improve the prevention of mottling, an alkylene glycol derivative having a flash point of 50 to 150° C. can be used in combination with the diethylene glycol dialkyl ether. Examples of such alkylene glycol derivatives having a flash point of 50 to 150°C include (poly)ethylene glycol dialkyl ethers such as triethylene glycol dimethyl ether, triethylene glycol diethyl ether, and tetraethylene glycol dimethyl ether; (poly)propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, tetrapropylene glycol diethyl ether, and tetrapropylene glycol dimethyl ether; (poly)propylene glycol monoalkyl ethers such as propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether; and (poly)propylene glycol monoalkyl ethers such as propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, and dipropylene glycol monobutyl ether acetate. Alkyl ether monoalkyl esters, (poly)ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, and tetraethylene glycol monobutyl ether, (poly)ethylene glycol monoalkyl ether monoalkyl esters such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, and triethylene glycol monomethyl ether acetate, (poly)ethylene glycol diesters such as ethylene glycol diacetate, diethylene glycol diacetate, and triethylene glycol diacetate, and ethylene glycol monomethyl ether acetate,Examples of the monoether monoesters include (poly)ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether acetate, and triethylene glycol monobutyl ether acetate. Among alkylene glycol derivatives having a flash point of 50 to 150° C., diethylene glycol ethyl methyl ether and diethylene glycol diethyl ether can be mentioned first. Furthermore, ethylene glycol diethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, and the like, which have a flash point outside the range of 50 to 150°C, may be used in combination so long as the flash point of the entire solvent is not significantly changed.

[0036] (Other ingredients) Furthermore, in the active energy ray-curable ink composition for ink-jet printing of the present invention, various additives such as a surfactant, a plasticizer, a polymerization inhibitor, a surface conditioner, an ultraviolet protection agent, a light stabilizer, and an antioxidant can be used as necessary.

[0037] (Viscosity of active energy ray-curable ink composition for inkjet printing) The active energy ray-curable ink composition for ink jet printing of the present invention preferably has a viscosity of 30.0 mPa·s or less at 25° C. If the viscosity exceeds 30 mPa·s, it may become difficult to eject the ink composition from the ink jet printing nozzle. The viscosity was measured using an E-type viscometer (product name: RE100L type viscometer, manufactured by Toki Sangyo Co., Ltd.) at 25° C. and 20 rpm.

[0038] (Production of active energy ray-curable ink composition for inkjet printing) Next, a method for producing the actinic ray-curable ink composition for ink-jet printing of the present invention using these materials will be described. The active energy ray-curable ink composition for inkjet printing of the present invention can be obtained by dispersing and mixing using a dispersing machine such as a wet circulation mill, a bead mill, a ball mill, a sand mill, an attritor, a roll mill, a DCP mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a high-pressure homogenizer (such as Microfluidizer, Nanomizer, Ultimizer, Genus PY, or DeBEE2000), or a pearl mill, and adjusting the viscosity of the active energy ray-curable ink composition for inkjet printing to be 2 to 10 mPa s. The total organic solvent content in the active energy ray-curable ink composition for ink-jet printing of the present invention is the amount obtained by subtracting the total amount of each solid content and other additives used as necessary from the total amount of the ink composition, and it is preferable to appropriately change the content so that the ink viscosity falls within the above-mentioned range. The active energy ray-curable ink composition for inkjet printing of the present invention thus obtained can be used by an inkjet printer on a substrate having at least a surface layer made of paper or a resin such as a vinyl chloride polymer or an ethylene-vinyl acetate copolymer.

[0039] (Manufacturing method of printed matter) Next, a method for producing a printed matter using the active energy ray-curable ink composition for ink-jet printing of the present invention will be described. The method for producing a printed matter of the present invention includes a step of printing the above-described active energy ray-curable ink composition for inkjet printing on a substrate by an inkjet system. The substrate is not particularly limited. For example, the substrate may be a resin substrate, paper, capsule, gel, metal foil, glass, wood, cloth, or the like. The ink composition of the present embodiment exhibits excellent bending resistance even when the substrate is folded after being printed on the substrate. Therefore, the ink composition is particularly suitable for use when the substrate is a substrate used for applications in which the substrate is folded, such as a cardboard sheet. When the substrate is a corrugated board sheet such as a C liner or a K liner, the ink composition may be applied directly to the corrugated board sheet, or may be applied after providing a precoat layer (primer layer) on the corrugated board sheet or performing a corona discharge treatment or the like. In recent years, waste paper or recycled paper may be used for the corrugated board sheet in consideration of the environment. When a K liner is used as the corrugated board sheet, the surface has rough unevenness, the color is unclear, and the ink has high permeability when printed. Therefore, when the ink composition is printed on the corrugated board sheet, the brown color of the liner base paper, which is the base, is likely to cause a decrease in print quality.

[0040] In particular, if the color of the base is expressed in the printed portion, the inkjet image will look dull and the appearance of the printed matter may be impaired. In order to eliminate the above-mentioned unevenness and the like, a precoat layer is appropriately provided on such corrugated board sheets. The precoat layer (primer layer) is provided for the purpose of adjusting the whiteness and color of the liner base paper that constitutes the corrugated cardboard sheet and increasing the whiteness of the base. The precoat layer can be formed by applying a precoat agent containing a pigment and an adhesive. The pigment is not particularly limited. For example, the pigment may be titanium dioxide (anatase, rutile), aluminum hydroxide, barium sulfate, calcium carbonate, amorphous silica, clay, or other extender pigments. The content of the white pigment is preferably 20 to 85 parts by mass, more preferably 20 to 80 parts by mass, in 100 parts by mass of the precoat agent. The binder resin used in the precoat layer of the corrugated board is preferably an aqueous resin. The aqueous resin is preferably a natural resin, a synthetic resin, etc., and more preferably a starch derivative, casein, shellac, a polyvinyl alcohol derivative, an acrylic resin, or a maleic acid resin. More specifically, the aqueous resin is preferably an aqueous acrylic resin copolymerized with acrylic acid or methacrylic acid and its alkyl ester, or styrene as a main monomer component, an aqueous styrene-acrylic resin, an aqueous styrene-maleic acid resin, an aqueous styrene-acrylic acid-maleic acid resin, an aqueous polyurethane resin, an aqueous polyester resin, etc. The content of the binder resin is preferably 1 to 25 parts by mass, more preferably 1 to 15 parts by mass, in 100 parts by mass of the precoat agent.

[0041] The aqueous medium that can be used in the precoat layer (primer layer) can be water or a mixture of water and a water-miscible solvent. The water-miscible solvent can be lower alcohols, polyhydric alcohols, and their alkyl ethers or alkyl esters. Specifically, the water-miscible solvent can be lower alcohols such as methyl alcohol, ethyl alcohol, normal propyl alcohol, and isopropyl alcohol, polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoacetate, diethylene glycol monomethyl ether, and dipropylene glycol monomethyl ether. In addition to the components listed above, various additives such as film-forming agents, pigment dispersants or pigment dispersing resins, antiblocking agents, wetting agents, viscosity adjusters, pH adjusters, defoamers, and general surfactants may be appropriately selected and used in the precoat layer as necessary. The method of producing a precoat agent using these various materials is not particularly limited. As an example, a method of producing a precoat agent is generally a method of mixing and kneading a white pigment, an aqueous binder resin, water, a water-miscible solvent as required, and a pigment dispersant or a pigment dispersing resin, and further adding and mixing an additive, water, a water-miscible solvent as required, and the remaining predetermined materials. The precoat agent can be easily obtained by mixing the required amounts of the above components and mixing and dispersing them using a high-speed stirrer such as a homomixer or a lab mixer, or a disperser such as a three-roll mill or a bead mill. When a primer layer is provided, the thickness of the primer layer (the amount of the precoat agent applied) is not particularly limited. The primer layer has a solid content of 0.1 to 5 g / m 2 By having the thickness of the primer layer (amount of application of the precoat agent) within the above range, the whiteness and color of the corrugated cardboard sheet can be easily adjusted appropriately.

[0042]

[0043] Specific examples of the method for printing and curing the active energy ray-curable ink composition for inkjet printing of the present invention include a method in which the active energy ray-curable ink composition for inkjet printing of the present invention is ejected onto a substrate by an inkjet head, and then the coating film of the ink composition of the present invention that has landed on the substrate is exposed to light and cured. For example, ejection onto a substrate (printing of an image) can be performed by supplying the active energy ray-curable ink composition for inkjet printing of the present invention to a printer head compatible with low viscosity inks of an inkjet recording printer, and ejecting the ink composition from the printer head so that the coating film on the substrate has a thickness of, for example, 1 to 60 μm. Furthermore, exposure to light and curing (curing of an image) can be performed by irradiating the coating film of the active energy ray-curable ink composition for inkjet printing of the present invention, which has been applied onto a substrate as an image, with active energy rays. As a printer for inkjet recording that prints the active energy ray-curable ink composition for inkjet printing of the present invention, a printer for inkjet recording that has been conventionally used can be used. When a continuous type printer for inkjet recording is used, a conductivity imparting agent is further added to the active energy ray-curable ink composition for inkjet printing of the present invention to adjust the electrical conductivity. Examples of the active energy ray source for curing the coating film include ultraviolet rays (UV lamp), ultraviolet rays (light-emitting diode (LED)), electron beams, visible light, and the like. Specific examples of the device include ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, mercury xenon lamps, metal halide lamps, high power metal halide lamps, xenon lamps, pulsed xenon lamps, deuterium lamps, fluorescent lamps, Nd-YAG triple harmonic lasers, He-Cd lasers, nitrogen lasers, Xe-Cl excimer lasers, Xe-F excimer lasers, semiconductor excited solid-state lasers, LED lamps, and the like. From an environmental standpoint, a light-emitting diode (LED) that generates ultraviolet rays with an emission peak wavelength in the range of 350 to 420 nm is preferable. Note that ultraviolet light emitted from a light-emitting diode (LED) as a light source is defined as "light emitted from a light-emitting diode that generates ultraviolet light with an emission peak wavelength in the range of 350 to 420 nm." The temperature of the ink composition during printing may be room temperature, about 20 to 26° C., or other temperatures. EXAMPLES

[0043] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass." The materials used in the following Examples and Comparative Examples are as follows. The units of values ​​in the columns for pigment, dispersant, resin, solvent and total in the tables are "mass %".

[0044] (Pigments) PY155: Pigment Yellow 155 PV19: Pigment Violet 19 PB15:4: Pigment Blue 15:4 P.Bl.7: Pigment Black 7 PG7: Pigment Green 7 PO13: Pigment Orange 13 PV23: Pigment Violet 23 PY150: Pigment Yellow 150 (Pigment dispersant) PB822 (Ajisper PB822, manufactured by Ajinomoto Fine-Techno Co., Ltd.)

[0045] (Amine modified oligomer) CN371 (Sartomer) (Photopolymerization initiator) TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide SB-PI719: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide Esacure ONE: Oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone} TPO-L: Ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate Omnipol TP (IGM) (sensitizer) Omnipol TX (IGM) DETX: Diethylthioxanthone (Lambson) (Polymerization inhibitor) MEHQ (hydroquinone monomethyl ether) HQ (hydroquinone) (Surface conditioner) BYK-331: Silicone Surfactant

[0046] (Examples 1 to 15, Comparative Examples 1 to 6) <Production of active energy ray-curable ink composition for inkjet printing> According to the formulation in Table 1 (the blending ratio of each material is in mass %), after stirring and mixing each material, it was kneaded to obtain pigment dispersion liquids of various colors. Then, an ink composition for active energy ray-curable inkjet printing of the examples was obtained according to the formulation in Table 2. <Corrugated board substrate> K liner, C liner

[0047] <Precoat agent> 45 parts by mass of calcium carbonate with an average particle diameter of 0.05 μm, 25 parts by mass of a styrene maleic acid resin with an acid value of 170 mg KOH / g (solid content 25%), and 30 parts by mass of water were dispersed with a bead mill to obtain a 45% slurry of calcium carbonate. 80 parts by mass of the 45% slurry of calcium carbonate and 20 parts by mass of a styrene-maleic acid resin with an acid value of 170 mg KOH / g (solid content 25%) were mixed and stirred to obtain a precoat agent. <Coating of the precoat agent on the K liner> The precoat agent adjusted above was applied to the K liner using a 0.1 mm Mayer bar so that the coating amount was about 4 g / m 2 of the coating amount. Then, the drying of the precoat agent-coated surface was carried out by hot air drying.

[0048] <Evaluation method and evaluation criteria> The evaluation criteria described in Table 2 are as follows. (Viscosity) The viscosity of the active energy ray-curable inkjet printing ink compositions obtained in the examples and comparative examples was measured using an E-type viscometer (product name: RE100L type viscometer, manufactured by Toki Sangyo Co., Ltd.) under the conditions of a temperature of 25 °C and a rotor rotation speed of 20 rpm.

[0049] (Coating film odor) After forming and curing a coating film on the substrate so that the size of the coating film became 8 cm × 12 cm, the substrate was put into a chuck bag of 24 cm × 34 cm, and the odor inside the bag was confirmed after one hour. Ten people were asked to smell it and evaluate it in the following five grades. The table shows the average value of the ten people rounded off to the decimal point. 5: Odorless 4: Low odor 3: Medium odor 2: Strong odor 1: Extremely stinky

[0050] (Storage stability) The actinic ray-curable ink composition for ink-jet printing was placed in a glass bottle, sealed, and stored at 70° C. for 7 days, after which the condition was evaluated according to the following evaluation criteria. ◯: Neither thickening nor sedimentation was observed in the actinic ray-curable ink composition for ink-jet printing. Δ: The actinic energy ray-curable ink composition for ink-jet printing showed increased viscosity and precipitates, which returned to their original state when lightly shaken. ×: The actinic energy ray-curable ink composition for ink-jet printing showed thickening or sedimentation to such an extent that it could not be restored even by vigorously shaking.

[0051] (Discharge stability) An inkjet recording device equipped with an inkjet nozzle and an active energy ray curable ink composition for inkjet printing were placed in an atmosphere at 25° C. for 24 hours, and the temperatures of the inkjet recording device and the active energy ray curable ink composition for inkjet printing were adjusted to 25° C. Thereafter, the ink composition was used to continuously print (print) on a K liner and a C liner on which a precoat had been applied at 25° C., and the ejection stability was evaluated according to the following evaluation criteria. ◯: There was no disturbance in printing and the ink was discharged stably. △: There was some disturbance in the printing, but the ink was discharged almost stably. ×: Printing was disturbed or ink could not be ejected stably.

[0052] (curable) An inkjet recording device equipped with an inkjet nozzle and an active energy ray curable ink composition for inkjet printing were placed in an atmosphere at 25° C. for 24 hours, and the temperatures of the inkjet recording device and the active energy ray curable ink composition for inkjet printing were adjusted to 25° C. Thereafter, the ink composition was used to continuously print on a K liner and a C liner to which a precoat had been applied at 25° C., and then the ink composition was used to continuously print on a K liner and a C liner to which a precoat had been applied at 25° C., and the ink composition was then used to continuously print on a K liner and a C liner to which a precoat had been applied at 2 cm from a UV-LED lamp manufactured by Phoseon Technology, with a UV cumulative light quantity of 180 mJ / cm. 2 The mixture was cured with. Then, using a conveyor-type light irradiation device (Heraeus STM-250E-16, lamp: Z-8 lamp (metal halide type)), 120W x 50m / min, UV cumulative light amount 75mJ / cm 2 [The UV integrated light amount was determined by measuring the amount of irradiation at the measurement ranges of 250-260 nm, 280-320 nm, 320-390 nm, and 395-445 nm using a UVIMAP (UM 365H-S) manufactured by EIT Co., Ltd.] The obtained curable coating film was rubbed with a cotton swab, and the curability was evaluated based on the degree of removal according to the following evaluation criteria. ○: There was no take. △: There was a slight takeover. ×: There was a takeover.

[0053] (hardening wrinkles) The ink composition was printed on the K liner and C liner to which the precoat had been applied, and the printed sample was visually evaluated for the presence of hardening wrinkles. ◯: No hardening wrinkles. ×: Hardening wrinkles.

[0054] (Bending resistance) An ink composition was printed on the precoat layer of a K liner and a C liner, each of which had a precoat layer formed on one side, and the liner was folded 90 degrees so that the printed surface was facing outward (so that the back sides of the K liner and C liner, not the printed sides, faced each other), and evaluated according to the evaluation criteria below. ◯: When folded, no creases or fine cracks were observed in the coating film. △: Fine cracks occurred when bent. ×: Creases occurred when folded.

[0055] (Abrasion resistance) The cured films obtained in the above curability evaluation were visually observed for the degree to which the cured film was removed from the K liner and C liner to which the precoat was applied when the coating film was rubbed 200 times with 500 g of bleached cloth using a Gakushin type fastness tester (manufactured by Daiei Scientific Instruments Manufacturing Co., Ltd.), and evaluated according to the following evaluation criteria. ◯: No removal of the cured film was observed. △: There were scratches on the surface of the cured film. ×: The cured film was removed and the sheet was visible.

[0056] (water resistance) The cured films obtained in the above curability evaluation were visually observed to see how well they were removed from the K liner and C liner to which the precoat was applied when the coating film was rubbed 30 times with 500 g of water-soaked bleached cloth using a Gakushin type fastness tester (manufactured by Daiei Scientific Instruments Manufacturing Co., Ltd.), and evaluated according to the following evaluation criteria. ◯: No removal of the cured film was observed. △: There were scratches on the surface of the cured film. ×: The cured film was removed and the sheet was visible.

[0057] [Table 1]

[0058] [Table 2] JPEG0007662647000003.jpg160170

[0059]

[0113] According to each of the Examples which are examples in accordance with the present invention, an active energy ray-curable ink composition for inkjet printing was obtained which has a low viscosity, is odorless, has excellent storage stability, ejection stability and curing properties, does not produce curing wrinkles upon curing, and produces a cured coating film which is also excellent in bending resistance, abrasion resistance and water resistance. However, Comparative Example 1, which did not contain the amine-modified oligomer, was inferior in curability, bending resistance, and abrasion resistance, and Comparative Example 2, which contained an excess of the amine-modified oligomer, was high in viscosity and had poor storage stability and ejection stability. Comparative Example 3, which had a low content of the component satisfying requirement C, had poor bending resistance, and Comparative Example 4, which had an excessive content of the component satisfying requirement C, had poor storage stability, developed hardening wrinkles, and had poor abrasion resistance. Moreover, according to Comparative Example 5 in which the component satisfying requirement B was excessive, the coating film had poor water resistance.

Claims

1. An active energy ray-curable inkjet ink composition that satisfies the following requirements A to D: A: Contains 1.0 to 20.0 mass % of an amine-modified oligomer in the total active energy ray-polymerizable components; B: Contains 8.0 to 20.0 mass % of an alkoxy group-containing (meth)acrylate in the total active energy ray-polymerizable components; C: Contains 2.0 to 25.0 mass % of an alkyl group-containing (meth)acrylate having 10 to 20 carbon atoms in the total active energy ray-polymerizable components; D: At least one selected from the group consisting of 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, dipropylene glycol diacrylate, propoxylated (2) neopentyl glycol diacrylate, 1,10-decanediol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate is contained in an amount of 30.0 to 60.0% by mass in all active energy ray-polymerizable components.

2. An active energy ray-curable inkjet ink composition that satisfies the following requirements A to E: A: Contains 1.0 to 20.0 mass % of an amine-modified oligomer in the total active energy ray-polymerizable components; B: Contains 2.0 to 20.0 mass % of an alkoxy group-containing (meth)acrylate in the total active energy ray-polymerizable components; C: Contains 2.0 to 25.0 mass % of an alkyl group-containing (meth)acrylate having 10 to 20 carbon atoms in the total active energy ray-polymerizable components; D: At least one selected from the group consisting of 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, dipropylene glycol diacrylate, propoxylated (2) neopentyl glycol diacrylate, 1,10-decanediol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate is contained in an amount of 30.0 to 60.0% by mass based on the total active energy ray-polymerizable components; E: The ink composition contains 5.0 to 30.0% by mass of a (meth)acrylic monomer having a hydroxyl group.

3. An active energy ray-curable inkjet ink composition that satisfies the following requirements A to D: A: Contains 1.0 to 20.0 mass % of an amine-modified oligomer in the total active energy ray-polymerizable components; B: Contains 2.0 to 20.0 mass % of an alkoxy group-containing (meth)acrylate in the total active energy ray-polymerizable components; C: The total active energy ray-polymerizable component contains 2.0 to 25.0 mass % of a (meth)acrylate containing an alkyl group having 10 to 20 carbon atoms, and at least a part of the (meth)acrylate containing an alkyl group having 10 to 20 carbon atoms is lauryl acrylate and / or stearyl acrylate; D: At least one selected from the group consisting of 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, dipropylene glycol diacrylate, propoxylated (2) neopentyl glycol diacrylate, 1,10-decanediol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate is contained in an amount of 30.0 to 60.0% by mass in all active energy ray-polymerizable components.

4. The active energy ray-curable ink composition for inkjet printing according to any one of claims 1 to 3, wherein at least a part or all of requirement B is a polyfunctional alkoxy group-containing (meth)acrylate monomer, and the polyfunctional alkoxy group-containing (meth)acrylate monomer is contained in an amount of 5.0 to 20.0 mass % of all active energy ray-polymerizable components.

5. The actinic ray-curable ink composition for ink-jet printing according to any one of claims 1 to 4, further comprising a photopolymerization initiator.

6. The actinic ray-curable ink composition for ink-jet printing according to any one of claims 1 to 5, further comprising a colorant.

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