Active energy ray curable ink composition for ink jet printing

Abstract

The present invention addresses the problem of providing an actinic ray curable ink composition that is for inkjet printing and that has a low viscosity, and has the effects of providing an odor-free coating film after being cured, having excellent curability, having no tackiness, and providing a cured coating film having excellent bending resilience, rub resistance, and water resistance. As a solution, provided is an actinic ray curable ink composition that is for inkjet printing and that meets requirements A-E. (A) The contained amount of an amine-modified oligomer is 1.0-20.0 mass% in the actinic ray curable ink composition for inkjet printing. (B) The contained amount of a (meth)acrylate monomer having an alkoxy group is 2.0-20.0 mass% in the actinic ray curable ink composition for inkjet printing. (C) The contained amount of a (meth)acrylate monomer having an alkyl group having 6-20 carbon atoms is 2.0-25.0 mass% in the actinic ray curable ink composition for inkjet printing. (D) The contained amount of at least one selected from 1,6-hexanedioldiacrylate, 3-methyl-1,5-pentanedioldiacrylate, dipropylene glycol diacrylate, 1,10-decanedioldiacrylate, propoxylated (2)neopentyl glycol diacrylate, and hydroxypivalate neopentyl glycol diacrylate is 30.0-60.0 mass% in the actinic ray curable ink composition for inkjet printing (E) The contained amount of ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide as a photopolymerization initiator is 3.0-15.0 mass% in the actinic ray curable ink composition for inkjet printing, and the contained amount of oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone) and / or 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)phenoxy]phenyl}-2-methylpropanone as a photopolymerization initiator is 2.0-10.0 mass% in the actinic ray curable ink composition for inkjet printing, and the total contained amount of the polymerization initiators is 6.0-25.0 mass% in the actinic ray curable ink composition for inkjet printing.

Description

[Technical field]

[0001] The present invention relates to an ink composition for inkjet printing curable with active energy rays that is suitable for printing on substrates such as papers and sheets made of resins such as vinyl chloride polymers and ethylene-vinyl acetate copolymers, in particular papers such as cardboard sheets, and a printed matter obtained using the ink composition. [Background technology]

[0002] As described in Patent Document 1, it is known that preventing the occurrence of curing wrinkles during curing of photocurable inkjet ink is an issue. Furthermore, an inkjet ink composition containing an amine-modified oligomer and an alkoxy group-containing monomer is also known, as described in Patent Document 2. However, such an ink composition does not satisfy the requirements C and D of the present invention. Furthermore, with the rise in awareness of environmental conservation, attention is being paid to the need to minimize waste by reconsidering the materials used in everyday items. [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 active energy ray-curable ink composition for inkjet printing, which has a low viscosity, and has the effects of providing a coating film after curing that is odorless, has excellent curability, is free of tackiness, and provides a cured coating film that is excellent in bending resistance, abrasion resistance, and water resistance. [Means for solving the problem]

[0005] Means of Solving the Problems The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by using a specific composition, thereby completing the present invention. That is, the present invention is as follows. 1. An actinic ray-curable ink composition for ink-jet printing, which satisfies the following requirements (A) to (E). The content of the amine-modified oligomer (A) in the actinic energy ray-curable ink composition for inkjet printing is 1.0 to 20.0% by mass. (B) An active energy ray-curable ink composition for inkjet printing contains a (meth)acrylate monomer having an alkoxy group at 2.0 to 20.0% by mass. (C) The active energy ray-curable ink composition for inkjet printing contains 2.0 to 25.0% by mass of a (meth)acrylate monomer having an alkyl group having 6 to 20 carbon atoms. (D) At least one selected from the group consisting of 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, dipropylene glycol diacrylate, 1,10-decanediol diacrylate, propoxylated (2) neopentyl glycol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate is contained in an active energy ray-curable ink composition for inkjet printing at 30.0 to 60.0% by mass. (E) as a photopolymerization initiator, ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide is contained in an active energy ray-curable inkjet printing ink at 3.0 to 15.0 mass % and oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone) and / or 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)phenoxy]phenyl}-2-methylpropanone is contained in an active energy ray-curable inkjet printing ink composition at 2.0 to 10.0 mass %, The total content of the photopolymerization initiator in the active energy ray-curable ink composition for inkjet printing is 6.0 to 25.0% by mass. 2. The active energy ray-curable ink composition for inkjet printing according to 1, wherein at least a part of the (B) (meth)acrylate monomer having an alkoxy group is a polyfunctional (meth)acrylate monomer, and the active energy ray-curable ink composition for inkjet printing contains this polyfunctional (meth)acrylate monomer in an amount of 5.0 to 20.0 mass %. 3. The actinic ray-curable ink composition for ink-jet printing according to 1 or 2, wherein one of the (meth)acrylate monomers having an alkyl group having 6 to 20 carbon atoms is lauryl acrylate and / or stearyl acrylate. 4. The actinic ray-curable ink composition for ink-jet printing according to any one of 1 to 3, wherein one of the (meth)acrylate monomers having an alkyl group having 10 to 20 carbon atoms is lauryl acrylate synthesized using a compound derived from a plant. 5. The actinic ray-curable ink composition for ink-jet printing according to any one of 1 to 4, wherein the 1,10-decanediol diacrylate is synthesized using a compound derived from a plant. 6. The actinic ray-curable ink composition for ink-jet printing according to any one of 1 to 5, further comprising (H) a colorant. Effect of the Invention

[0006] The active energy ray-curable ink composition for inkjet printing of the present invention has low viscosity, and after curing, the coating film has no odor, is excellent in curability, is free of tackiness, 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 E, and will be described below in order. <Requirement A> The requirement A is that the content of the amine-modified oligomer in the actinic energy ray-curable ink composition for inkjet printing is 1.0 to 20.0% by mass. Among them, an acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule is preferred. Here, the acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule is not limited. For example, the photopolymerizable functional group in the acrylated amine compound may be a functional group that undergoes polymerization reaction by visible light or invisible light including ionizing radiation such as ultraviolet light or electron beam, and can form a crosslinked bond between molecules. In addition, the photopolymerizable functional group includes both a narrow-sense photopolymerizable functional group that is directly activated by light irradiation and undergoes photopolymerization reaction, and a broad-sense photopolymerizable functional group that initiates and promotes polymerization reaction by the action of active species generated from a photopolymerization initiator when the photopolymerizable functional group and a photopolymerization initiator are coexisting and irradiated with light.

[0008] The photopolymerizable functional group may be one having photoradical polymerization reactivity such as an ethylenic double bond, one having photocationic polymerization and photoanionic polymerization reactivity such as a cyclic ether group such as an epoxy group, etc. Among these, the photopolymerizable functional group is preferably an ethylenic double bond such as a (meth)acryloyl group, a vinyl group, an allyl group, etc., and more preferably a (meth)acryloyl group. It is preferable that the acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule has both (meth)acryloyl groups and an amine value of 130 to 142 KOHmg / g. The amine value means the amine value per 1 g of solid content, and is a value measured by potentiometric titration (e.g., COMTITE (AUTO TITRATOR COM-900, BURET B-900, TITSTATION K-900), manufactured by Hiranuma Sangyo Co., Ltd.) using a 0.1 N aqueous hydrochloric acid solution, and then converted into an equivalent amount of potassium hydroxide.

[0009] The acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule is preferably an acrylated amine compound obtained by reacting a bifunctional (meth)acrylate with an amine compound. Bifunctional (meth)acrylates include alkylene glycol di(meth)acrylates such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, and neopentyl glycol di(meth)acrylate, di(meth)acrylates of ethylene oxide adducts of bisphenol A, di(meth)acrylates of ethylene oxide adducts of bisphenol F, and bisphenol A di(meth)acrylates of ethylene oxide adducts of bisphenol B. Examples of the difunctional (meth)acrylate include bisphenol alkylene oxide adduct di(meth)acrylates such as di(meth)acrylate of ethylene oxide adduct of phenol S, di(meth)acrylate of ethylene oxide adduct of thiobisphenol, and di(meth)acrylate of ethylene oxide adduct of brominated bisphenol A, polyalkylene glycol di(meth)acrylates such as polyethylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate, and di(meth)acrylate of hydroxypivalic acid neopentyl glycol ester. Among these, the bifunctional (meth)acrylate is preferably 1,6-hexanediol di(meth)acrylate.

[0010] Examples of the amine compound include monofunctional amine compounds such as benzylamine, phenethylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, n-pentylamine, isopentylamine, n-hexylamine, cyclohexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine, and n-octadecylamine; diethylenetriamine, triethylenetriamine, and the like; Examples of suitable amine compounds include polyfunctional amine compounds such as ethylenetetramine, tetraethylenepentamine, 1,6-hexamethylenediamine, 1,8-octamethylenediamine, 1,12-dodecamethylenediamine, o-phenylenediamine, p-phenylenediamine, m-phenylenediamine, o-xylylenediamine, p-xylylenediamine, m-xylylenediamine, menthanediamine, bis(4-amino-3-methylcyclohexyl)methane, isophoronediamine, 1,3-diaminocyclohexane, and spiroacetal diamines. The amine compound may also be a high molecular weight type polyfunctional amine compound such as polyethyleneimine, polyvinylamine, and polyallylamine.

[0011] The acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule is preferably a compound obtained by reacting 1,6-hexanediol di(meth)acrylate with an amine compound. Specifically, it is an acrylated amine compound such as CN371, CN373, CN383, CN386 (manufactured by Sartomer), which is an oligomer of an acrylated amine compound having two active energy ray polymerizable functional groups and two amino groups in the molecule. In addition, EB7100 (EBECRYL 7100, manufactured by Cytec), Agi008 (manufactured by DSM), etc. can also be used. The content of the amine-modified oligomer in the actinic energy ray-curable ink composition for inkjet printing is 1.0 mass % or more, preferably 3.0 mass % or more, more preferably 4.0 mass % or more, and even more preferably 5.0 mass % or more. Furthermore, the content of the amine-modified oligomer in the actinic energy ray-curable ink composition for inkjet printing is 20.0 mass % or less, preferably 15.0 mass % or less, more preferably 12.0 mass % or less, and most preferably 9.0 mass % or less. When the content of the amine-modified oligomer is less than 1.0% by mass, the curability of the actinic energy ray-curable ink composition for inkjet printing tends to be poor, whereas when the content exceeds 20.0% by mass, the storage stability and ejection stability of the ink composition tend to be reduced.

[0012] Furthermore, the content of the amine-modified oligomer relative to all polymerizable components in the active energy ray-curable ink composition for inkjet printing is preferably 2.0 mass % or more, more preferably 3.0 mass % or more, and even more preferably 4.0 mass % or more. Furthermore, the content of the amine-modified oligomer relative to all polymerizable components in the active energy ray-curable ink composition for inkjet printing is preferably 16.0 mass % or less, more preferably 10.0 mass % or less, and even more preferably 8.0 mass % or less.

[0013] <Requirement B> Requirement B is that the active energy ray-curable ink composition for ink-jet printing contains an alkoxy group-containing (meth)acrylate monomer 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)acrylate 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, propoxylated (2) neopentyl glycol di(meth)acrylate, and propoxylated (2) neopentyl glycol diacrylate 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.

[0014] The content of the alkoxy group-containing (meth)acrylate monomer in the actinic energy ray-curable ink composition for inkjet printing is preferably 5.0% by mass or more, and more preferably 10.0% by mass or more. Furthermore, the content of the alkoxy group-containing (meth)acrylate monomer in the active energy ray-curable ink composition for inkjet printing is preferably 18.0 mass % or less, more preferably 16.0 mass % or less, and even more preferably 14.0 mass % or less. If the content of the alkoxy group-containing (meth)acrylate monomer 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 20.0% by mass, the water resistance will be poor. The content of the alkoxy group-containing (meth)acrylate monomer in the total polymerizable components of the active energy ray-curable ink composition for inkjet printing is preferably 6.0% by mass or more, more preferably 10.0% by mass or more, and even more preferably 12.0% by mass or more. It is also preferably 20.0% by mass or less, more preferably 18.0% by mass or less, and even more preferably 16.0% by mass or less.

[0015] <Requirement C> Requirement C is that the active energy ray-curable ink composition for inkjet printing contains 2.0 to 25.0 mass % of a (meth)acrylate having an alkyl group having 6 to 20 carbon atoms. The alkyl group having 6 to 20 carbon atoms may have any of a linear, branched, or alicyclic structure. Here, the (meth)acrylate containing an alkyl group having 6 to 20 carbon atoms is a monofunctional (meth)acrylate. For example, Examples of the acrylate include tridecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, isotetradecyl (meth)acrylate, isobornyl (meth)acrylate, and cyclohexyl (meth)acrylate. Stearyl acrylate and lauryl acrylate are preferred.

[0016] The content of the (meth)acrylate containing an alkyl group having 6 to 20 carbon atoms in the actinic energy ray-curable ink composition for inkjet printing is 2.0 mass % or more, preferably 5.0 mass % or more, and more preferably 7.0 mass % or more. Furthermore, the content of the (meth)acrylate containing an alkyl group having 6 to 20 carbon atoms in the actinic energy ray-curable ink composition for inkjet printing is 25.0 mass % or less, preferably 18.0 mass % or less, and more preferably 15.0 mass % or less. If the content of the (meth)acrylate containing an alkyl group having 6 to 20 carbon atoms in the actinic energy ray-curable ink composition for inkjet printing is less than 2.0 mass %, the bending resistance will be poor, and if it exceeds 25.0 mass %, the abrasion resistance will be poor. The content of the alkyl group-containing (meth)acrylate having 6 to 20 carbon atoms in all polymerizable components of the active energy ray-curable ink composition for inkjet printing is preferably 7.0% by mass or more, more preferably 9.0% by mass or more, and even more preferably 10.0% by mass or more, and is preferably 25.0% by mass or less, more preferably 22.0% by mass or less, and even more preferably 18.0% by mass or less.

[0017] One of the raw materials for this alkyl group-containing (meth)acrylate having 6 to 20 carbon atoms is (meth)acrylic acid, and the other raw material is an alcohol having 6 to 20 carbon atoms. This alcohol can be obtained, for example, from a plant-derived raw material and has renewable carbon. The plant-derived raw material is a plant-derived raw material such as palm oil, palm kernel oil, coconut oil, etc. Since alkyl groups having 6 to 20 carbon atoms have a relatively large number of carbon atoms, the more (meth)acrylate made from such an alkyl group in the actinic energy ray-curable ink composition for inkjet printing is used, the more biomass-derived carbon can be used in the entire composition.

[0018] <Requirement D> Requirement D is to use at least one selected from the group consisting of 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, dipropylene glycol diacrylate, 1,10-decanediol diacrylate, propoxylated (2) neopentyl glycol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate. The total content of the compounds satisfying Requirement D is 30.0 to 60.0% by mass in the active energy ray-curable ink composition for inkjet printing. If the total amount of requirement D is less than 30.0% by mass, the abrasion resistance is poor, and if it exceeds 60.0% by mass, the bending resistance is poor. The raw materials for these compounds may be derived from plants.

[0019] <Requirement E> Requirement E is that the active energy ray-curable inkjet printing ink contains 3.0 to 15.0 mass % of ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide as a photopolymerization initiator, and 2.0 to 10.0 mass % of oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone) and / or 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)phenoxy]phenyl}-2-methylpropanone as a photopolymerization initiator, and the total content of the photopolymerization initiator in the active energy ray-curable inkjet printing ink is 6.0 to 25.0 mass %.

[0020] As an example of the content of the photopolymerization initiator used in requirement E, when ultraviolet light (UV) or ultraviolet light (light-emitting diode (LED)) is used as the light source, the content of the photopolymerization initiator in the active energy ray-curable ink composition for inkjet printing is preferably 6.0% by mass or more, and more preferably 8.0% by mass or more. The content of the photopolymerization initiator in the active energy ray-curable ink composition for inkjet printing is preferably 25.0% by mass or less, and more preferably 15.0% by mass or less. When the content of the photopolymerization initiator is within the above range, the active energy ray-curable ink composition for inkjet printing can have sufficient curability, internal curability, and be low cost.

[0021] The active energy ray-curable ink composition for ink-jet printing of the present invention may contain a photopolymerization initiator other than those described above, as long as the effect of the present invention is not impaired. When an electron beam is used as the active energy ray, a photopolymerization initiator may or may not be contained. Examples of photopolymerization initiators that can be used include the following. Acylphosphine oxide polymerization initiators: bis-2,6-dimethoxybenzoyl-2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzyl-diphenylphosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, etc. α-Hydroxyketone polymerization initiators, such as 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-hydroxycyclohexyl phenyl ketone (Irgacure 184), 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 1-hydroxycyclohexyl phenyl ketone.

[0022] Others include benzophenone compounds (4,4'-diethylaminobenzophenone, etc.) and thioxanthone compounds (2,4-diethylthioxanthone), 2-methyl-1-(4-methylthio)phenyl-2-morpholinopropan-1-one, 4'-(methylthio)-α-morpholino-α-methylpropiophenone, thiophenyl compounds (4-benzoyl-4'-methyldiphenyl sulfide), 1-chloro-4-propoxythioxanthone, isopropylthioxanthone), 2,2-dimethyl-2-hydroxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-benzyl-2-dimethylamino-1-(morpholinophenyl)-butan-1-one, 4-benzoyl-4'-methyldiphenyl sulfide, ethyl Michler's ketone, 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.

[0023] (sensitizer) In the active energy ray-curable ink composition for inkjet printing of the present invention, a photosensitizer (compound) that has light absorption properties mainly in the ultraviolet wavelength range of 400 nm or more and exhibits a sensitizing function for the curing reaction by light in that range of wavelengths can be used together with the polymerization initiator in order to promote curing properties against ultraviolet light using a light-emitting diode (LED) as a light source. Note that the above phrase "exhibits a sensitizing function by light with a wavelength of 400 nm or more" refers to having light absorption properties in the wavelength range of 400 nm or more. By using such a sensitizer, the ink composition of this embodiment can promote LED curing properties.

[0024] Examples of such sensitizers include anthracene-based sensitizers and thioxanthone-based sensitizers, and preferably thioxanthone-based sensitizers. These can be used alone or in combination of two or more kinds. Specific examples of the sensitizers include anthracene sensitizers such as 9,10-dibutoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, and 9,10-bis(2-ethylhexyloxy)anthracene, and thioxanthone sensitizers such as 2,4-diethylthioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone. Representative examples of commercially available products include anthracene sensitizers such as DBA and DEA (manufactured by Kawasaki Chemical Industries, Ltd.), and thioxanthone sensitizers such as DETX, ITX, and CPTX (manufactured by LAMBSON), and Omnipol TX (manufactured by IGM). The content of the sensitizer is preferably 0 to 8.0% by mass based on the total mass of the active energy ray-polymerizable component. If the content exceeds 8.0% by mass, no improvement in effect is observed, and it is undesirable because it becomes an excessive addition. When a thioxanthone-based sensitizer is used as the sensitizer, it tends to discolor the active energy ray-curable ink composition for inkjet printing to yellow, resulting in a hue that is more yellowish than the color (original hue) based on the pigment or the like. Therefore, it is preferable to appropriately determine the content of the thioxanthone-based sensitizer for each color. Specifically, in the white ink composition and the clear ink composition, which are susceptible to changes in color, it is preferable not to include a thioxanthone compound as a sensitizer. In addition, in the magenta ink composition and the cyan ink composition, changes in hue become a problem, so it is preferable to use a thioxanthone compound within a range in which problems with hue do not occur. In addition, in the black ink composition and the yellow ink composition, since discoloration does not affect the hue and the active energy ray polymerizability is poorer than other hues, it is preferable to use a thioxanthone compound in combination as a sensitizer.

[0025] (Requirement G) Requirement G that may be adopted is that the content of the (meth)acrylate monomer having a hydroxyl group is 0 to 25.0% by mass in all polymerizable components in the active energy ray-curable ink composition for inkjet printing. In the case of inks other than white inks, the content of the (meth)acrylate monomer having a hydroxyl group can be preferably 5.0 to 25.0 mass %, and more preferably 7.0 to 25.0 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 a (meth)acrylate monomer having a hydroxyl group. In the case of a white ink, it is preferable that the active energy ray-curable ink composition for inkjet printing does not contain a (meth)acrylate monomer having a hydroxyl group, but the active energy ray-curable ink composition for inkjet printing may contain a (meth)acrylate monomer having a hydroxyl group. As the (meth)acrylate monomer having a hydroxyl group, 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)acrylate monomers having a hydroxyl group, such as 4-hydroxybutyl (meth)acrylate, which has little odor, are preferred.

[0026] <Requirement H> As an optional 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.

[0027] <Other polymerizable compounds> In the present invention, in addition to the above-mentioned polymerizable components, other polymerizable compounds may be contained within the range in which the performance is not deteriorated and the odor is small. In the description of the compounds below, the (poly) before the polyol portion means a condensation product of mono-, di- or higher polyols. Benzyl methacrylate, butyl (meth)acrylate, ethyl carbitol (meth)acrylate, caprolactone (meth)acrylate, methoxytripropylene glycol (meth)acrylate, ethyl carbitol (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.

[0028] (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; ,2-Hexanediol di(meth)acrylate, 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 butyl-2-ethyl-1,3-propanediol 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, Polyethylene glycol di(meth)acrylate, Polypropylene glycol di(meth)acrylate,

[0029] ((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,

[0030] ((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, dipentaerythritol hexa(meth)acrylate,

[0031] (Other poly(meth)acrylates) 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, etc. Incidentally, 2-(2-vinyloxyethoxy)ethyl acrylate, methyl 2-(allyloxymethyl)acrylate, and amide group-containing monomers may or may not be contained.

[0032]

[0113] It is also possible to use resins other than the above-mentioned acrylic resins in combination, as long as the performance of the active energy ray-curable ink composition for ink jet printing of the present invention is not impaired, such as 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.

[0033] (Requirement F) As the colorant contained in the actinic energy ray-curable ink composition for inkjet printing of the present invention, known pigments and dyes that have been conventionally used in actinic energy ray-curable ink compositions for inkjet printing can be used, and pigments such as organic color pigments and inorganic color pigments are preferred. The ink composition of the present embodiment suitably contains a colorant as component (I). By incorporating a colorant, ink compositions of various colors can be prepared.

[0034] 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.

[0035] Specific examples of color pigments for each representative hue of the ink composition of the present invention 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 (CI Pigment Black 7) or the like. 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. The content of the colorant in the ink composition is preferably 20% by mass or less. When the content of the colorant is within the above range, the ink composition provides suitable image quality for the resulting printed matter and has excellent viscosity characteristics.

[0036] (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 them, polymeric compounds are preferred, such as carbodiimide compounds described in JP2004-083872A, WO2003 / 076527A, and WO2004 / 000950A, basic functional group-containing copolymers AJISPER PB821 and 822 (manufactured by Ajinomoto Fine-Techno Co., Ltd.) (acid value and amine value are both 10 to 20 mgKOH / g), 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. 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.

[0037] (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.

[0038] 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.

[0039] 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 monoether monoesters such as 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.

[0040] (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.

[0041] (Viscosity of active energy ray-curable ink composition for inkjet printing) The actinic 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 it exceeds 30.0 mPa·s, it may become difficult to eject the ink composition from an 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.

[0042] (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 content of the organic solvent in the actinic 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 ink jet printing of the present invention thus obtained can be used on paper substrates such as printing paper and cardboard paper by using an ink jet printer.

[0043] (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. This production method includes a step of printing the above-described active energy ray-curable ink composition for ink jet printing onto a substrate by an ink jet method. The substrate is not particularly limited. For example, the substrate is a substrate such as a resin substrate, paper, capsule, gel, metal foil, glass, wood, or cloth, particularly paper such as a cardboard sheet. 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 cardboard sheet such as a C liner or a K liner, the ink composition may be applied directly to the cardboard sheet, or may be applied after providing a precoat layer (primer layer) on the cardboard sheet or performing a corona discharge treatment or the like. That is, in recent years, waste paper, recycled paper, etc. are sometimes used for cardboard sheets in consideration of the environment. When a K liner is used as the cardboard 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 cardboard sheet, the brown color of the liner base paper, which is the base, is likely to cause a decrease in print quality. 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 is provided for the purpose of adjusting the whiteness and color of the liner base paper constituting the corrugated cardboard sheet, increasing the whiteness of the base, etc. 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.

[0044] 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. 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.

[0045] 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.

[0046]

[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.

[0047] 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. Specifically, the device may be, for example, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a mercury xenon lamp, a metal halide lamp, a high power metal halide lamp, a xenon lamp, a pulsed xenon lamp, a deuterium lamp, a fluorescent lamp, an Nd-YAG triple harmonic laser, a He-Cd laser, a nitrogen laser, a Xe-Cl excimer laser, a Xe-F excimer laser, a semiconductor excited solid state laser, an LED lamp, 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. The 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

[0048] 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 %".

[0049] (Pigments) PB15:4: Pigment Blue 15:4 Titanium dioxide

[0050] CN371 (Sartomer) (amine-modified oligomer) EOTMPTA: Ethoxytrimethylolpropanetriacrylate (alkoxy group-containing photopolymerizable compound) HDDA: 1,6-Hexanediol diacrylate LA: Lauryl acrylate STA: Stearyl acrylate 4HBA: 4-Hydroxybutyl acrylate

[0051] (Photopolymerization initiator) TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide Irgacure 819: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide TPOL: Ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide Esacure ONE: Oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone} KIP160: 2-Hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)phenoxy]phenyl}-2-methylpropanone

[0052] (sensitizer) DETX: Diethylthioxanthone (Lambson) TX1: Omnipol TX (IGM) (Polymerization inhibitor) UV-5 (Surface conditioner) BYK-331: Silicone Surfactant (Pigment dispersant) PB822 (Ajinomoto Fine-Techno Co., Ltd.)

[0053] (Examples 1 to 12, Comparative Examples 1 to 8) <Manufacture of Ink Composition for Active Energy Ray-Curable Inkjet Printing> According to the formulations in Table 1, ink compositions for active energy ray-curable inkjet printing of the examples and comparative examples were obtained.

[0054] <Corrugated Base Material> K liner, C liner <Primer> 45 parts by mass of calcium carbonate with an average particle size of 0.05 μm, 25 parts by mass of a styrene maleic acid resin with an acid value of 170 mgKOH / g (solid content 25%), and 30 parts by mass of water were dispersed in 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 mgKOH / g (solid content 25%) were mixed and stirred to obtain a primer. <Coating of Primer on K Liner> The primer 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. Subsequently, the drying of the primer-coated surface was carried out by hot air drying.

[0055] <Evaluation Methods and Criteria> The evaluation base materials described in Table 1 are as follows. (Viscosity) For the ink compositions for active energy ray-curable inkjet printing obtained in the examples and comparative examples, the viscosity was measured using an E-type viscometer (trade 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.

[0056] (Coating Film Odor) After forming and curing a coating film on the base material so that the coating film size became 8 cm × 12 cm, the base material 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 nearest decimal place 5: Odorless 4: Low odor 3: Medium odor 2: Strong odor 1: Extremely stinky

[0057] (curable) The inkjet recording device and the 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 set to 25° C. Thereafter, the active energy ray curable ink composition was used to continuously print on a K liner and a C liner precoated with the ink composition at 25° C., and then the ink composition was exposed to UV light of 180 mJ / cm using a UV-LED lamp manufactured by Phoseon Technology, with a distance of 2 cm between the lamp and the ink application surface. 2 The resulting curable coating film was rubbed with a cotton swab, and the curability was evaluated based on how well it was removed according to the following evaluation criteria. ○: There was no take. △: There was a slight takeover. ×: There was a takeover.

[0058] (tackiness) An inkjet printing (recording) device equipped with an inkjet nozzle for low-viscosity ink and each ink composition were placed in an atmosphere at 25°C for 24 hours, and the temperature of the inkjet printing device and each ink composition was set to 25°C. After that, each ink composition was continuously printed on PVC80 (vinyl chloride resin sheet (12 cm x 18 cm), manufactured by Lintec Corporation) at 25°C, and then cured with a UV-LED light lamp manufactured by Phoseon Technology Co., Ltd. at a distance of 2 cm between the lamp and the coated surface of the ink at an integrated UV light amount of 180 J / m2. The surface of the coating was touched with a finger, and the state of the coating was visually confirmed to evaluate the tackiness. ○: No fingerprints are left on the coating. △: Fingerprints are slightly left on the coating. ×: Fingerprints remain on the coating.

[0059] (Bending resistance) The ink composition was printed on the precoated K liner and C liner, and then folded 90 degrees so that the printed surface was facing outward (so that the back surfaces of the K liner and C liner, not the printed surfaces, 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.

[0060] (Abrasion resistance) The cured films obtained in the curing 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 200 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.

[0061] (water resistance) The cured films obtained in the curing evaluation were visually observed to see how well they were removed from the K liner and C liner to which the precoat had been 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.

[0062] [Table 1] JPEG0007651577000002.jpg144170

[0063]

[0113] According to each of the Examples which are examples according to the present invention, it was possible to obtain an active energy ray-curable ink composition for inkjet printing which has a low viscosity, a coating film which has no odor, excellent curability, a cured coating film which is free of tackiness, and which is also excellent in bending resistance, abrasion resistance and water resistance. In contrast, Comparative Example 1, which did not contain ESACURE ONE or KIP160, had a coating odor and was poor in curability, tackiness, adhesion to some substrates, abrasion resistance and water resistance, while Comparative Example 2, which also did not contain ESACURE ONE or KIP160 and had a high total content of Irgacure 819 and TPOL, was poor in tackiness and abrasion resistance. In addition, Comparative Example 3, which had a low total TPOL content, had a coating odor and was poor in curability, tackiness, abrasion resistance and water resistance, Comparative Example 4, which did not contain the amine-modified oligomer, had a coating odor and was poor in curability, tackiness, bending resistance and abrasion resistance, and Comparative Example 5, which had a low content of the compound satisfying requirement D, had a coating odor and was poor in curability, tackiness, abrasion resistance and water resistance. Furthermore, Comparative Example 6, which did not contain the compound of requirement C and did not contain a (meth)acrylate monomer having an alkyl group having 6 to 20 carbon atoms, was poor in bending resistance, Comparative Example 7, which contained an excess of the component of requirement D, had a coating odor and was poor in curability, tackiness, bending resistance and abrasion resistance, and Comparative Example 8, which contained an excess of the compound of requirement C, had a coating odor and was poor in curability, tackiness and abrasion resistance.

Claims

1. An active energy ray-curable ink composition for inkjet printing that satisfies the following requirements A to E: (A) the content of the amine-modified oligomer in the active energy ray-curable ink composition for inkjet printing is 1.0 to 20.0% by mass; (B) an alkoxy group-containing (meth)acrylate monomer is contained in an amount of 2.0 to 20.0% by mass in the active energy ray-curable ink composition for inkjet printing; (C) a (meth)acrylate monomer having an alkyl group having 6 to 20 carbon atoms (excluding those having an alkoxy group) is contained in an amount of 2.0 to 25.0% by mass in the active energy ray-curable ink composition for ink-jet printing; (D) at least one selected from the group consisting of 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, dipropylene glycol diacrylate, 1,10-decanediol diacrylate, propoxylated (2) neopentyl glycol diacrylate, and hydroxypivalic acid neopentyl glycol diacrylate is contained in an amount of 30.0 to 60.0% by mass in the active energy ray-curable ink composition for inkjet printing; (E) ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide as a photopolymerization initiator in an amount of 3.0 to 15.0% by mass in the active energy ray-curable ink composition for ink-jet printing; an active energy ray-curable ink composition for ink-jet printing contains 2.0 to 10.0% by mass of oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone) and / or 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)phenoxy]phenyl}-2-methylpropanone; The total content of the photopolymerization initiator in the active energy ray-curable inkjet printing ink is 6.0 to 25.0% by mass.

2. 2. The active energy ray-curable ink composition for inkjet printing according to claim 1, wherein at least a part of the (meth)acrylate monomer having an alkoxy group of (B) is a polyfunctional (meth)acrylate monomer, and the active energy ray-curable ink composition for inkjet printing contains this polyfunctional (meth)acrylate monomer in an amount of 5.0 to 20.0 mass %.

3. The active energy ray-curable ink composition for inkjet printing according to claim 1 or 2, wherein the (C) (meth)acrylate monomer having an alkyl group having 6 to 20 carbon atoms is lauryl acrylate and / or stearyl acrylate.

4. The active energy ray-curable ink composition for inkjet printing according to any one of claims 1 to 3, wherein one of the (meth)acrylate monomers having an alkyl group having 6 to 20 carbon atoms (C) is lauryl acrylate synthesized using a compound derived from plants.

5. 5. The active energy ray-curable ink composition for ink-jet printing according to claim 1, wherein the 1,10-decanediol diacrylate is synthesized using a compound derived from a plant.

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

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