Active energy ray-curable inkjet ink composition

Abstract

The purpose of this invention is to obtain an active energy radiation-curable inkjet ink composition, characterized in that, while improving color development, it can be cured by LED, further resulting in a film with high hardness, excellent abrasion resistance, and excellent water resistance. As a solution, an active energy radiation-curable inkjet ink composition is provided, characterized in that it contains pigments, a pigment dispersant, and a photopolymerizable compound. The pigments contain Pigment Violet 19 and Pigment Orange 71, with Pigment Violet 19 comprising 30.0–85.0% by mass relative to the total mass of Pigment Violet 19 and Pigment Orange 71. The photopolymerizable compound satisfies all the main conditions of (A) to (F) below: (A) it contains 0.20–15.0% by mass of a polyfunctional amine-modified oligomer in the total amount of polymerizable components; (B) it contains 50.0% by mass of a polyfunctional amine-modified oligomer in the total amount of polymerizable components. (C) Contains monofunctional monomers accounting for 35.0% or more of the total polymerizable components and having a glass transition temperature of 20°C or more; (D) Contains monofunctional monomers accounting for 35.0% or more of the total polymerizable components and having a glass transition temperature of 10°C or less; (E) Contains polyfunctional monomers accounting for 2.0 to 11.0% of the total polymerizable components and having a glass transition temperature of 10°C or less; (F) Contains nitrogen-containing monofunctional monomers accounting for 10.0 to 25.0% of the total polymerizable components.

Description

Technical Field

[0001] This invention relates to an active energy ray curable ink composition for inkjet printing and a printing method thereof. Background Technology

[0002] Patent document 1 describes an inkjet ink containing pigment violet 19.

[0003] Patent document 2 describes an ink composition containing any one of pigment orange 43, pigment green 36, and pigment violet 23.

[0004] Patent document 3 describes an inkjet ink composition containing at least one organic pigment that is orange, purple, or green.

[0005] Furthermore, as described in these patent documents, ink compositions containing either pigment orange or pigment violet are known individually.

[0006] Furthermore, as described in Patent Document 4, active energy ray curable inkjet printing ink compositions containing monofunctional, multifunctional photopolymerizable compounds and oligomers are known.

[0007] According to this active energy ray curable ink composition for inkjet printing, it exhibits excellent performance in various aspects such as storage stability, effectiveness, and viscosity. However, it has not been confirmed whether it can be used on various substrates, nor has it been explored whether it can be used on other substrates such as polycarbonate or polyvinyl chloride, or whether it can improve the hardness, abrasion resistance, and water resistance of the cured coating.

[0008] That is, the ink composition for active energy ray curing inkjet is not intended to be applicable to a wider range of substrates, or to have higher hardness, or to have properties such as abrasion resistance or water resistance, so that the cured film can be used in a wider range of fields.

[0009] Therefore, depending on the application or environment of the substrate to which the coating is formed using an active energy ray curable inkjet ink composition, there is a possibility that it may not be adequately addressed.

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2018-95739

[0012] Patent Document 2: Japanese Patent Application Publication No. 2020-84102

[0013] Patent Document 3: Japanese Patent Application Publication No. 2009-67955

[0014] Patent Document 4: Japanese Patent Application Publication No. 2019-31618 Summary of the Invention

[0015] As described in the aforementioned patent documents, ink compositions containing either pigment orange or pigment violet are known individually.

[0016] However, in such ink compositions, as a magenta ink composition, it is impossible to simultaneously achieve a more suitable optical density and b... Value. The objective of this invention is to obtain an active energy ray curable ink composition for inkjet printing, characterized in that, while improving color development, it can be cured by LED, further resulting in a film with high hardness, excellent abrasion resistance, and excellent water resistance.

[0017] The inventors conducted in-depth research to solve the above-mentioned problems and found that by preparing an active energy ray curable inkjet ink composition having a specific pigment composition, the above-mentioned problems could be solved, thus completing the present invention.

[0018] The active energy ray curable ink composition of the present invention achieves suitable optical density and b color due to its excellent color rendering properties as red. It has excellent adhesion to various substrates, can be fully cured by active energy rays with LED as the light source, and the resulting coating has high hardness, exhibiting excellent abrasion resistance and water resistance. Detailed Implementation

[0019] The active energy ray curable ink composition for inkjet printing of the present invention will be described below.

[0020] First, the glass transition temperature in this invention is defined as follows.

[0021] <Glass transition temperature>

[0022] Regarding the glass transition temperature of the resin in this invention, when the resin is an acrylic copolymer resin, it is the theoretical glass transition temperature obtained by the following Wood formula.

[0023] Wood type: 1 / Tg=W1 / Tg1+W2 / Tg2+W3 / Tg3+ +Wx / Tgx

[0024] [In the formula, Tg1~Tgx represent monomers 1, 2, 3 that constitute the resin.] The glass transition temperatures of the respective homopolymers of x, where W1~Wx represent monomers 1, 2, 3, and 4. The respective polymerization fractions of x, and Tg representing the theoretical glass transition temperature. Wherein, the glass transition temperature in Wood's formula is an absolute temperature.

[0025] <Pigment>

[0026] The active energy ray curable ink composition of the present invention contains pigment violet 19 and pigment orange 71.

[0027] Furthermore, relative to the total mass of Pigment Violet 19 and Pigment Orange 71, Pigment Violet 19 is 30.0 to 85.0% by mass. Preferably, Pigment Violet 19 is 40.0% or more by mass, more preferably 45.0% or more by mass, further preferably 50.0% or more by mass, and most preferably 55.0% or more by mass.

[0028] Furthermore, the amount of pigment violet 19 is preferably 83.0% by mass or less, more preferably 75.0% by mass or less, even more preferably 70.0% by mass or less, and most preferably 65.0% by mass or less.

[0029] When the content ratio of Pigment Violet 19 and Pigment Orange 71 is within this range, the color rendering of red in the printing section becomes excellent.

[0030] From the viewpoint of improving the color development of the printing section, the total amount of pigment violet 19 and pigment orange 71 relative to the total amount of polymerizable components in the ink composition is preferably 2.0% by mass or more, more preferably 3.0% by mass or more, and even more preferably 4.0% by mass or more. Furthermore, from the viewpoint of improving ejection stability, it is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and even more preferably 7.0% by mass or less.

[0031] The pigments used in this invention need to be the specific pigments described above, but other pigments may be formulated without compromising the effects of this invention.

[0032] Other pigments include organic and inorganic pigments other than Pigment Violet 19 and Pigment Orange 71 used in inkjet ink compositions.

[0033] Examples of organic pigments include dye lake pigments, azo pigments, benzimidazolone pigments, phthalocyanine pigments, quinacridone pigments, anthraquinone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, perylene pigments, violet ketone pigments, diketopyrrolopyrrole pigments, isoindolinone pigments, nitro pigments, nitroso pigments, anthraquinone pigments, yellow anthraquinone pigments, quinophthalone pigments, pinantrone pigments, and indigoantrone pigments. Examples of inorganic pigments include carbon black, titanium dioxide, zinc white, iron oxide red, graphite, iron black, chromium oxide green, and aluminum hydroxide. These pigments can also be surface-treated with known surface treatment agents.

[0034] The following pigments can be listed as specific examples of representative hues of the pigments.

[0035] Examples of yellow pigments include CI pigments 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, and 213.

[0036] Examples of magenta pigments include CI pigments 5, 7, 12, 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, and 270.

[0037] Examples of 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.

[0038] Examples of orange pigments include CI pigments 1, 2, 3, 4, 5, 13, 15, 16, 17, 19, 24, 31, 34, 36, 38, 40, 43, 46, 48, 49, 51, 60, 61, 62, 64, 65, 66, 67, 68, 69, 72, 73, 74, 81, etc.

[0039] Examples of purple pigments include CI pigments 1, 2, 3, 3:1, 3:3, 5:1, 13, 17, 23, 25, 27, 29, 31, 32, 36, 37, 38, 42, and 50.

[0040] Examples of black pigments include carbon black (CI Pigment Black 7).

[0041] As a white pigment, examples include titanium dioxide and aluminum oxide, and it can also be surface-treated with various materials such as aluminum oxide and silicon dioxide.

[0042] <Pigment Dispersant>

[0043] In the active energy ray curable ink composition of the present invention, a pigment dispersant is preferably used.

[0044] Since the pigment dispersant is used to improve the dispersibility of pigments and the storage stability of active energy ray curable inkjet ink compositions, conventionally used pigment dispersants can be used without particular restriction, with polymeric pigment dispersants being preferred. The pigment dispersant can be used alone or in combination of two or more.

[0045] Examples of dispersants for the aforementioned polymeric pigments include carbodiimide dispersants, polyester amine dispersants, fatty acid amine dispersants, modified polyacrylate dispersants, modified polyurethane dispersants, multi-chain polymeric nonionic dispersants, and polymeric ionic surfactants.

[0046] Examples of such polymeric pigment dispersants include BYKJET-9150, BYKJET-9151, BYKJET-9170, DISPERBYK-168, DISPERBYK-190, DISPERBYK-198, DISPERBYK-2010, DISPERBYK-2012, DISPERBYK-2015 (BYK Chemicals), SMA1440, SMA2625, SMA17352, SMA3840, SMA1000, SMA2000, SMA3000 (Cray Valley), JONCRYL67, JONCRYL678, JONCRYL586, JONCRYL611, JONCRYL680, and JON. CRYL682, JONCRYL690, JONCRYL819, JONCRYL-JDX5050, EFKA4550, EFKA4560, EFKA4585, EFKA4701, EFKA5220, EFKA6230 (BASF), SOLSPERSE20000, SOLSPERSE27000, SOLSPERSE41000, SOLSPERSE41090, SOLSPERSE43000, SOLSPERSE44000, SOLSPERSE46000, SOLSPERSE47000, SOLSPERSE54000, SOLSPERSE56000 (Lubrizol), AJISPER PB821, AJISPER PB822, AJISPER PB824, AJISPER PB881 (Ajinomoto Fine-Techno), etc.

[0047] From the viewpoint of improving the dispersibility of pigments and the storage stability of active energy ray curable inkjet ink compositions, the content of pigment dispersant is preferably 1.0% by mass or more, more preferably 5.0% by mass or more, and further preferably 100% by mass or less, more preferably 60.0% by mass or less, relative to the total mass of pigments.

[0048] <(A) Polyfunctional amine modified oligomers>

[0049] The polyfunctional amine-modified oligomer contained in the photopolymerizable compound is not particularly limited as long as it is a polyfunctional amine-modified (meth)acrylate oligomer having at least one amino group and at least two (meth)acryloyl groups in its molecule. Furthermore, the number of (meth)acryloyl groups in the polyfunctional amine-modified (meth)acrylate oligomer molecule is not particularly limited, but preferably two to six, and more preferably two to four. When the number of (meth)acryloyl groups is within the above range, the polyfunctional amine-modified (meth)acrylate oligomer readily reacts with the polymerizable compound, and the viscosity of the active energy radiation-curable inkjet ink composition is also easily achieved within a suitable range.

[0050] Polyfunctional amine-modified (meth)acrylate oligomers can be synthetic products synthesized by polymerizing desired monomers, or they can be commercially available products. For example, GENOMER5161, GENOMER5275 (RAHN), CN371, CN371NS, CN373, CN383, CN384, CN386, CN501, CN503, CN550, CN551 (Sartomer), EBECRYL80, EBECRYL81, EBECRYL83, EBECRYL7100, EBECRYL84, EBECRYLP115 (Dairu), LAROMER PO 83F, LAROMER PO 84F, Laromer LR8946, Laromer LR8956, Laromer LR8996, Laromer LR8894 (BASF), AgiSyn001, AgiSyn002, Agisyn003, Agisyn008 (DSM Coating) (Resin, Inc.), Photomer4771, Photomer4775, Photomer4967, Photomer5096, Photomer5662, Photomer5930 (Cognnis), DoublecureEPD, DoublecureOPD, Doublecure115, Doublecure225, Doublecure645, PolyQ222, PolyQ226, PolyQ224, PolyQ101 (DoubleBond Chemicals). Among these, oligomers having two photopolymerizable functional groups within the molecule are preferred, and (meth)acryloyl groups are more preferred.

[0051] Regarding the polyfunctional amine-modified (meth)acrylate oligomers usable in this invention, they contain 0.20 to 15.0% by mass in the total amount of polymerizable components in the active energy radiation-curable inkjet ink composition. Preferably, they contain 0.40% by mass or more, more preferably 0.50% by mass or more. Furthermore, they preferably contain 10.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 1.00% by mass or less.

[0052] The viscosity of the polyfunctional amine-modified oligomer is not limited. In particular, when the viscosity at 25°C is below 2000 cps, the overall viscosity of the active energy ray curable inkjet ink composition can be set to an appropriate range, which is preferred.

[0053] Furthermore, without impairing the effects based on the present invention, for example, epoxy (meth)acrylate oligomers may also be included.

[0054] Epoxy (meth)acrylate oligomers can be synthetic products synthesized by polymerizing desired monomers, or they can be commercially available products. Examples include EBECRYL 3708, EBECRYL 1606 (Dairu), CN116, CN120B60, CN120M50, CN131B, CN132, CN137, CN152, CN153, CN2102E, and CN2003 (Sartomer).

[0055] <(B) Monofunctional Monomer>

[0056] Examples of monofunctional monomers contained in photopolymerizable compounds include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, isoamyl methacrylate, octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, isodecyl methacrylate, tridecyl methacrylate, isomyristyl methacrylate, stearyl methacrylate, isostearyl methacrylate, isobornyl methacrylate, lauryl methacrylate, and other alkyl methacrylates.

[0057] Cyclohexyl methacrylate, butylcyclohexyl acrylate, trimethylcyclohexyl acrylate, adamantyl methacrylate, dicyclopentyl methacrylate, dicyclopentenyl methacrylate, and other cyclic hydrocarbon-containing methacrylates.

[0058] Ethyl carbitol (meth)acrylate, ethoxyethyl (meth)acrylate, 2-methoxyethyl acrylate, butoxyethyl (meth)acrylate, and other alkoxyalkyl (meth)acrylates.

[0059] Hydroxymethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, polyethylene glycol (meth)acrylate, hydroxybutyl methacrylate, hydroxyphenoxypropyl methacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-ethylhexyl-diethylene glycol (meth)acrylate, 2-acryloyloxyethyl hexahydrophthalic acid, butoxyethyl acrylate, ethoxydiethylene glycol (meth)acrylate, diethylene glycol monoethyl ether (meth)acrylate, caprolactone (meth)acrylate, ethyl carbitol acrylate, methoxydiethylene glycol (meth)acrylate, butoxydiethylene glycol (meth)acrylate, butoxytriethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethylhexyl-diethylene glycol acrylate, phenoxydiethylene glycol (meth)acrylate, etc., are (meth)acrylates containing hydroxyl and ether bonds.

[0060] Methoxy polyethylene glycol (meth)acrylate, methoxy propylene glycol (meth)acrylate, and other polyalkylene glycol monoalkyl ethers (meth)acrylates.

[0061] Polyalkylene glycol monoaryl ethers such as hexaethylene glycol monophenyl ether are (meth)acrylates, glycerol (meth)acrylates, 2-hydroxyethyl (meth)acrylate and other (meth)acrylates with hydroxyl groups, tetrahydrofurfuryl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolane-4-yl)methyl (meth)acrylate, (3-ethyloxetane-3-yl)methyl methacrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane methyl acetal (meth)acrylate and other (meth)acrylates with heterocyclic structures.

[0062] Phenolic glycol-modified acrylates, 2-hydroxypropyl acrylate (meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate (meth)acrylate, ethoxyphenyl acrylate (EO 2 mol), ethoxyphenyl acrylate (EO 1 mol), 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid, lactone-modified flexible acrylates, tert-butylcyclohexyl acrylate (meth)acrylate, EO (ethylene oxide)-modified succinic acid (meth)acrylate, ethyleneoxyethoxyethyl acrylate (meth)acrylate, methylphenoxyethyl acrylate (meth)acrylate, 2-phenoxyethyl acrylate (meth)acrylate and its ethylene oxide modified derivatives, 2-ethylhexyl carbitol (meth)acrylate, ethyl carbitol (meth)acrylate, acryloylmorpholine, acrylonitrile, acrylamide, diethylacrylamide, styrene, benzyl acrylate (meth)acrylate, (meth)acrylic acid, and other compounds.

[0063] Acryloylmorpholine or vinylcaprolactam, (meth)acrylamide, N-methoxymethylacrylamide, diacetoneacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, hydroxymethyl (meth)acrylamide, di(2-hydroxyethyl) (meth)acrylamide, di(3-hydroxypropyl) (meth)acrylamide, di(4-hydroxybutyl) (meth)acrylamide and other N-alkyl alcohols (C1~5) (meth)acrylamides and 1~3 molar adducts of these N-alkyl alcohols (C1~5) (meth)acrylamides) in ethylene oxide or propylene oxide, etc., monofunctional monomers with amide structures, N-vinylcarbazole, N-vinylacetamide, N-vinylpyrrolidone and other nitrogen-containing monomers.

[0064] Furthermore, the monofunctional monomer (B) in this invention also includes monomers listed below such as (C) monofunctional monomers with a glass transition temperature of 20°C or higher, (D) monofunctional monomers with a glass transition temperature of 10°C or lower, and (F) nitrogen-containing monofunctional monomers. Moreover, one or more monofunctional monomers conforming to the following criteria are included in the composition of (B) monofunctional monomers, while also being components of (C), (D), and (F). The results are recorded in their respective proportions.

[0065] Monofunctional monomers are specifically incorporated into ink compositions for inkjet printing that are cured by active energy radiation to achieve low viscosity. The composition contains at least 50.0% by mass of the monofunctional monomer in the total amount of polymerizable components, preferably at least 80.0% by mass, more preferably at least 90.0% by mass, and even more preferably at least 95.0% by mass. Furthermore, it is preferable to contain 99.0% by mass or less, more preferably 98.0% by mass or less, and even more preferably 97.0% by mass or less.

[0066] When the ink composition contains a monofunctional monomer with an amide structure, its content in the total polymerizable component of the active energy radiation curable inkjet ink composition is preferably 4.0% by mass or more, more preferably 8.0% by mass or more, further preferably 12.0% by mass or more, and most preferably 14.0% by mass or more. Furthermore, it is preferably 30.0% by mass or less, more preferably 25.0% by mass or less, further preferably 20.0% by mass or less, and most preferably 18.0% by mass or less.

[0067] The monofunctional monomer having an amide structure preferably contains vinylcaprolactam. The content of vinylcaprolactam in the total polymerizable component of the active energy radiation curable inkjet ink composition is preferably 3.0% by mass or more, more preferably 6.0% by mass or more, further preferably 10.0% by mass or more, and most preferably 13.0% by mass or more. Furthermore, it is preferably 25.0% by mass or less, more preferably 22.0% by mass or less, further preferably 20.0% by mass or less, and most preferably 18.0% by mass or less.

[0068] The monofunctional monomer having an amide structure preferably contains acryloylmorpholine. The content of acryloylmorpholine in the total polymerizable component of the active energy radiation curable inkjet ink composition is preferably 2.0% by mass or more, more preferably 3.0% by mass or more, further preferably 4.0% by mass or more, and most preferably 5.0% by mass or more. Furthermore, it is preferably 20% by mass or less, more preferably 10.0% by mass or less, further preferably 8.0% by mass or less, and most preferably 7.0% by mass or less.

[0069] <(C) Monofunctional monomers with a glass transition temperature above 20°C>

[0070] The monofunctional monomer with a glass transition temperature of 20°C or higher contained in the photopolymerizable compound is a monofunctional monomer with a glass transition temperature of 20°C or higher selected from the aforementioned monofunctional monomers. Examples include methyl methacrylate, n-propyl methacrylate, stearyl methacrylate, isobornyl methacrylate, cyclotrimethylolpropane methyl acetal (CTFA), adamantyl methacrylate, dicyclopentyl methacrylate, dicyclopentenyl methacrylate, styrene, acryloylmorpholine, acrylamide, N-vinylcaprolactam, methacrylic acid, acrylonitrile, vinyl acetate, etc. One or more of these monomers may be used.

[0071] Among the monofunctional monomers with a glass transition temperature of 20°C or higher, the monofunctional monomers having an amide structure and compounds having a cyclic structure are preferred. In addition to the monofunctional monomers having an amide structure, it is preferred to contain one or more of isobornyl (meth)acrylate or cyclic trimethylolpropane methyl acetal acrylate. From the perspective of obtaining better curability and adhesion of the coating film, it is preferred to further contain N-vinylcaprolactam.

[0072] More preferably, the total polymerizable content of monofunctional monomers with a glass transition temperature of 20°C or higher is 5.0% by mass or more of acrylamide monomers and / or 5.0% by mass or more of N-vinylcaprolactam.

[0073] Furthermore, among the monofunctional monomers with a glass transition temperature of 20°C or higher, monomers with a glass transition temperature of 50°C or higher are preferred, and monomers with a glass transition temperature of 70°C or higher are more preferred.

[0074] It may or may not contain 3,3,5-trimethylcyclohexyl acrylate.

[0075] The content of monofunctional monomers with a glass transition temperature of 20°C or higher is 35.0% by mass or more in the total amount of polymerizable components, preferably 38.0% by mass or more, more preferably 40.0% by mass or more, and even more preferably 42.0% by mass or more. Furthermore, it is preferable to contain 60.0% by mass or less, more preferably 55.0% by mass or less, and even more preferably 50.0% by mass or less. When the content of monofunctional monomers with a glass transition temperature of 20°C or higher is less than 35.0% by mass, the curability of the active energy ray curable inkjet ink composition of the present invention is reduced when photocured by LED.

[0076] <(D) Monofunctional monomers with a glass transition temperature below 10°C>

[0077] As a monofunctional monomer with a glass transition temperature of 10°C or less that can be used in this invention, particularly preferred examples include methyl acrylate, ethyl acrylate, n-butyl acrylate, n-hexyl methacrylate, 2-ethylhexyl (meth)acrylate, isononyl acrylate, tetrahydrofurfuryl (meth)acrylate, isooctyl (meth)acrylate, isoamyl acrylate, isomyristyl acrylate, lauryl acrylate, etc. Two or more of these monomers may also be used together.

[0078] The content of monofunctional monomers with a glass transition temperature of 10°C or less in the total polymerizable component is 35.0% by mass or more, preferably 38.0% by mass or more, more preferably 45.0% by mass or more, and even more preferably 50.0% by mass or more. Furthermore, it is preferable to contain 70.0% by mass or less, more preferably 60.0% by mass or less, and even more preferably 55.0% by mass or less.

[0079] When the content of monofunctional monomers with a glass transition temperature of 10°C or less is less than 35.0% by mass, the viscosity of the active energy ray curable inkjet ink composition of the present invention tends to become too high.

[0080] Furthermore, among monofunctional monomers with a glass transition temperature of 10°C or less, monomers with a glass transition temperature of -30°C or less are preferred, and monomers with a glass transition temperature of -50°C or less are even more preferred.

[0081] <(E) Multifunctional monomers with a glass transition temperature below 10°C>

[0082] As a multifunctional monomer with a glass transition temperature below 10°C that can be used in this invention, it is a compound having multiple carbon-carbon unsaturated bonds in its molecule. Examples include (meth)acrylate ethyleneoxyethoxyethyl ester, EO (10 mol or 20 mol) modified bisphenol A diacrylate, polyethylene glycol (400) di(meth)acrylate, polyethylene glycol (600) diacrylate, alkoxylated hexanediol diacrylate, ethoxylated (30) bisphenol A diacrylate, alkoxylated neopentyl glycol diacrylate, ethoxylated (3) trimethylolpropane triacrylate, ethoxylated (6) trimethylolpropane triacrylate, ethoxylated (9) trimethylolpropane triacrylate, propoxylated (3) trimethylolpropane triacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol (600) dimethacrylate, etc.

[0083] The content of the multifunctional monomers with a glass transition temperature of 10°C or less in the total polymerizable components is 2.0 to 11.0% by mass, preferably 3.0% by mass or more, more preferably 4.0% by mass or more. Furthermore, it is preferable to contain 9.0% by mass or less, more preferably 7.0% by mass or less, and even more preferably 5.0% by mass or less.

[0084] When the content of multifunctional monomers with a glass transition temperature below 10°C is less than 2.0% by mass, the adhesion to various substrates is poor, and the hardness, abrasion resistance, and water resistance of the cured coating also deteriorate. When the content of multifunctional monomers with a glass transition temperature below 10°C exceeds 11.0% by mass, the adhesion to various substrates deteriorates.

[0085] Furthermore, among the multifunctional monomers with a glass transition temperature of 10°C or less, monomers with a glass transition temperature of -20°C or less are preferred, and monomers with a glass transition temperature of -30°C or less are even more preferred.

[0086] In addition, it may or may not contain α,β-unsaturated ether monomers.

[0087] <(F) Nitrogen-containing monofunctional monomers>

[0088] Examples of nitrogen-containing monofunctional monomers that can be used in this invention include acryloylmorpholine, vinylcaprolactam, acrylonitrile, (meth)acrylamide, N-methoxymethylacrylamide, diacetone acrylamide, N,N-dimethylacrylamide, diethylacrylamide, N-vinylcarbazole, N-vinylacetamide, N-vinylpyrrolidone, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, hydroxymethyl(meth)acrylamide, di(2-hydroxyethyl)(meth)acrylamide, and di... (3-hydroxypropyl) (meth)acrylamide, di(4-hydroxybutyl) (meth)acrylamide and other N-alkyl alcohols (C1-5) (meth)acrylamides and 1-3 molar adducts of these N-alkyl alcohols (C1-5) (meth)acrylamides in ethylene oxide or propylene oxide, N-vinylcaprolactam, vinylmethyl oxazolidinone, caprolactone-modified tetrahydrofurfuryl methacrylate, (meth)acryloylpyrrolidine, (meth)acryloylpiperidine, cyclic trimethylolpropane methyl acetal (meth)acrylate, lactone-modified flexible acrylate.

[0089] Regarding the content of nitrogen-containing monofunctional monomers, it is preferably 10.0 to 25.0% by mass in the total amount of polymerizable components, more preferably 12.0% by mass or more, and even more preferably 15.0% by mass or more.

[0090] Furthermore, it is preferable to contain 22.0% by mass or less, more preferably 20.0% by mass or less, and even more preferably 18.0% by mass or less.

[0091] When the content of nitrogen-containing monofunctional monomers is less than 10.0% by mass, the curability is poor when using LEDs as a light source; when it exceeds 25.0% by mass, the adhesion to various substrates is poor.

[0092] (Other polymeric components)

[0093] In the active energy ray curable inkjet ink composition of the present invention, as other polymerizable components, it may also contain oligomers that are not polyfunctional amine modified oligomers, or polyfunctional monomers with a glass transition temperature exceeding 10°C, without impairing the effects of the present invention.

[0094] (Multifunctional monomers with a glass transition temperature exceeding 10°C)

[0095] Without impairing the effects of the present invention, the active energy ray curable ink composition for inkjet printing may contain multifunctional monomers with a glass transition temperature exceeding 10°C.

[0096] Examples of such multifunctional monomers are shown below. Higher concentrations result in poorer adhesion to the substrate.

[0097] Ethylene glycol dimethacrylate, propylene glycol dimethacrylate, butanediol dimethacrylate, hexanediol dimethacrylate, dipropylene glycol dimethacrylate, triethylene glycol dimethacrylate, tripropylene glycol dimethacrylate, 1,9-nonanediol dimethacrylate, neopentyl glycol dimethacrylate, dimethyloltricyclodecane dimethacrylate, neopentyl hydroxypentanoic acid neopentyl glycol dimethacrylate, polybutylene glycol dimethacrylate, trimethylolpropane trimethacrylate Esters and their ethylene oxide-modified derivatives, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate and its ethylene oxide-modified derivatives, dipentaerythritol penta(meth)acrylate and its ethylene oxide-modified derivatives, dipentaerythritol hexa(meth)acrylate and its ethylene oxide-modified derivatives, polyurethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, pentaerythritol ethoxytetraacrylate, caprolactam-modified dipentaerythritol hexaacrylate, ethoxylated bisphenol A diacrylate, alkoxylated tetrahydrofurfuryl acrylate, etc.

[0098] (Photopolymerization initiator)

[0099] The active energy ray curable inkjet ink composition of the present invention contains a photopolymerization initiator. This photopolymerization initiator is not particularly limited to any substance that begins polymerization upon receiving active energy rays; the photopolymerization initiator used in active energy ray curable inkjet ink compositions can be used.

[0100] Examples of photopolymerization initiators include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-keto alcohol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanone-based photopolymerization initiators, triazine-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators. Among these, triazine-based photopolymerization initiators and acylphosphine oxide-based photopolymerization initiators are preferred from the viewpoint of good curing properties relative to light emitted by light-emitting diodes (LEDs). These photopolymerization initiators can be used alone or in combination of two or more.

[0101] Examples of photopolymerization initiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, ethoxy(2,4,6-trimethylbenzoyl)phenylphosphine oxide, benzophenone, diethylthioxanthone, 2-methyl-1-(4-methylthio)phenyl-2-morpholinylpropane-1-one, 4-benzoyl-4'-methyldiphenyl sulfide, 1-chloro-4-propoxythioxanthone, isopropylthioxanthone, and 2-hydroxy-2-methyl-1-phenylpropane-1-one. 1-Hydroxycyclohexylphenyl ketone, bis-2,6-dimethoxybenzoyl-2,4,4-trimethylpentylphosphine oxide, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2,2-dimethyl-2-hydroxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4,6-trimethylbenzyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(morpholinophenyl)-butane-1-one, etc.

[0102] (sensitizer)

[0103] The active energy ray curable ink composition of the present invention may also contain a sensitizer from the viewpoint of improving curability. The sensitizer may be used alone or in combination of two or more.

[0104] Examples of anthracene sensitizers include 9,10-dibutoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, and 9,10-bis(2-ethylhexyloxy)anthracene; and thioxanthone sensitizers such as 2,4-diethylthioxanthone, 2,4-diethylthioxanthone-9-one, 2-isopropylthioxanthone, and 4-isopropylthioxanthone, with thioxanthone sensitizers being preferred. Commercially available examples of these sensitizers include anthracene sensitizers with trade names such as "DBA" and "DEA" (both from Kawasaki Chemical Industry Co., Ltd.), and thioxanthone sensitizers with trade names such as "DETX" and "ITX" (Lambson Co., Ltd.).

[0105] From the viewpoint of preventing excessive addition, the proportion of the sensitizer in the ink composition is preferably 5% by mass or less. Furthermore, as shown in this invention, thioxanthone-based sensitizers can be used for magenta-colored ink compositions.

[0106] In this invention, the ink composition preferably contains 7.0 to 14.0% by mass of a photopolymerization initiator and / or sensitizer relative to the total amount of polymerizable components. Here, when both a photopolymerization initiator and a sensitizer are present, this ratio is the ratio of their total amounts; when only one is present, it is the ratio of their individual amounts.

[0107] Color rendering of coatings based on active energy ray-cured ink compositions for inkjet printing

[0108] When the active energy ray curable ink composition of the present invention is used at 25°C, and a solid portion is formed on a polyvinyl chloride sheet using a 0.1 mm coating rod, the OD value (optical density) of the ink film is preferably 1.30 or more, and more preferably 1.33 or more.

[0109] In addition, b The value is preferably 28.0 or higher, more preferably 30.0 or higher, even more preferably 31.0 or higher, preferably 33.0 or lower, more preferably 32.5 or lower, and even more preferably 32.0 or lower.

[0110] In addition, OD value and b The values ​​were obtained by measuring a spectrophotometer / concentration meter (X-rite eXact).

[0111] (Other ingredients)

[0112] The active energy ray curable ink composition of the present invention may also contain various additives such as surfactants, organic solvents, polymerization inhibitors, preservation enhancers, ultraviolet absorbers, antioxidants, defoamers, mildew inhibitors, rust inhibitors, tackifiers, humectants, and pH adjusters as other components.

[0113] (surfactant)

[0114] In the active energy ray curable inkjet printing ink composition of the present invention, depending on the inkjet head used, known surfactants used in active energy ray curable inkjet printing ink compositions can be used without particular limitation, such as nonionic surfactants, cationic surfactants, anionic surfactants, and betaine surfactants. Specific examples of such surfactants include silicone surfactants such as polyether-modified silicone oil, polyester-modified polydimethylsiloxane, and polyester-modified methylalkyl polysiloxane, fluorinated surfactants, and acetylene surfactants. The surfactants can be used alone or in combination of two or more.

[0115] Examples of silicone surfactants include BYK-307, BYK-315N, BYK-331, BYK-333, BYK-347, BYK-348, BYK-349, BYK-345, BYK-377, BYK-378, and BYK-3455 (BYK Chemical Company).

[0116] Examples of fluorinated surfactants include F-410, F-444, F-553 (DIC), FS-65, FS-34, FS-35, FS-31, and FS-30 (DuPont).

[0117] Examples of acetylene surfactants include Dynol 607, Dynol 609, Olfine E1004, Olfine E1010, Olfine E1020, Olfine PD-001, Olfine PD-002W, Olfine PD-004, Olfine PD-005, Olfine EXP.4001, Olfine EXP.4200, Olfine EXP.4123, Olfine EXP.4300 (Nikshin Chemical Co., Ltd.), Surfynol 104E, Surfynol 104H, Surfynol 104A, Surfynol 104BC, Surfynol 104DPM, Surfynol 104PA, Surfynol 104PG-50, Surfynol 420, Surfynol 440, and Surfynol 465 (EVONIK Co., Ltd.).

[0118] In the active energy ray curable inkjet ink composition of the present invention, from the viewpoint of reducing the surface tension of the ink composition and improving the ejection stability from the inkjet head, the proportion of the surfactant is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and from the viewpoint of suppressing bubbles in the ink composition generated during mixing and improving ejection stability, it is preferably 1.5% by mass or less, more preferably 1% by mass or less.

[0119] When surface modifiers are present, the content of surface modifiers is not particularly limited, but preferably the content is such that the surface tension of the active energy ray curable inkjet ink composition reaches 22.0 to 30.0 mN / m, and more preferably 0.10 to 1.50 by mass in the active energy ray curable inkjet ink composition.

[0120] (solvent)

[0121] In the active energy ray curable inkjet ink composition of the present invention, a solvent may be added as needed. Examples of such solvents include ester-based organic solvents, ether-based organic solvents, ether-ester organic solvents, ketone-based organic solvents, aromatic hydrocarbon solvents, and nitrogen-containing organic solvents. Furthermore, solvents with a boiling point of 150-220°C at one atmosphere are also possible examples. From the viewpoint of curability of the ink composition and environmental considerations, it is preferable to avoid using such solvents as much as possible. Therefore, the proportion of such solvents in the ink composition is preferably 5% by mass or less, more preferably 2% by mass or less.

[0122] <Additives>

[0123] In the active energy ray curable inkjet printing ink composition of the present invention, various additives may be added as needed to exhibit various functionalities. Specifically, examples include surface conditioners, light stabilizers, surface treatment agents, antioxidants, anti-aging agents, crosslinking promoters, polymerization inhibitors, plasticizers, preservatives, pH adjusters, defoamers, and humectants. Furthermore, a non-curable resin that functions as a carrier may or may not be added. Additionally, it may or may not contain solvents.

[0124] (Preservative enhancer)

[0125] As a preservation enhancer, hindered amines such as N-CH3 type, NH type, and N-OR type can be used.

[0126] (UV absorber)

[0127] Ultraviolet absorbers include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylates, hydroxyphenyltriazine-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, nickel complex salt-based ultraviolet absorbers, etc.

[0128] (Antioxidants)

[0129] Antioxidants include phenolic antioxidants, amine antioxidants, sulfur antioxidants, and phosphorus antioxidants.

[0130] (Defoamer)

[0131] The defoamers include silicone defoamers, Pluronic (registered trademark) defoamers, etc.

[0132] The viscosity of the active energy ray curable inkjet ink composition of the present invention at 25°C is preferably 2000 cps or less, more preferably 30 cps or less, and even more preferably 10 cps or less. A viscosity modifier may be added to the ink composition as needed. Furthermore, the viscosity described in this application specification is the viscosity measured using an E-type viscometer (RE100L type viscometer, manufactured by Toki Sangyo Co., Ltd.) at 25°C and 20 rpm.

[0133] In addition, the surface tension is preferably 20.0~25.0 mN / m.

[0134] <Preparation Method of Active Energy Ray Curable Ink Composition for Inkjet Printing>

[0135] Next, a method for manufacturing the active energy ray curable inkjet ink composition of the present invention using these materials will be described.

[0136] The active energy radiation-curable inkjet ink composition of the present invention can be obtained by dispersing and mixing the components using a wet circulating mill, bead mill, ball mill, sand mill, vertical ball mill (attritor), roller mill, DCP mill, mixer, Henschel mixer, colloid mill, ultrasonic homogenizer, high-pressure homogenizer (Micro fluidizer, Nanomizer, Ultimizer, Genus PY, DeBEE2000, etc.), Pearl Mill, etc., and adjusting the viscosity of the active energy radiation-curable inkjet ink composition as needed. Alternatively, the active energy radiation-curable inkjet ink composition can also be prepared by mixing the pigment with the aforementioned pigment dispersant and the aforementioned photopolymerizable monomer to obtain a base ink composition in advance, and then adding the residual portions of the aforementioned components to achieve the desired composition.

[0137] <Printing Methods>

[0138] A printing method for an ink composition for inkjet printing based on the active energy ray curing method of the present invention will be described.

[0139] The inkjet printing apparatus used is not particularly limited, but examples include: supplying an ink composition for inkjet printing that is cured by active energy rays to the printhead of an inkjet recording printing apparatus, ejecting the ink composition from the printhead onto the substrate to be printed, and then exposing and curing the ink composition on the substrate by active energy rays. Examples of active energy rays include ultraviolet light, electron beams, and visible light emitted from light-emitting diodes (LEDs) or various lamps or electrodes. Curing performance is particularly superior compared to ultraviolet light using LEDs as a light source.

[0140] Furthermore, the substrate is not particularly limited, as long as it is a substrate suitable for conventionally known energy-curable inkjet ink compositions. Examples of suitable substrates include plastics, paper, capsules, gels, metal foils, glass, wood, and cloth. Examples of suitable plastics include polycarbonate, rigid vinyl chloride, flexible vinyl chloride, ABS, polyethylene, polyester, polypropylene, acrylic resin, and polystyrene.

[0141] Specifically, a method for printing and curing the ink composition of the present invention can be exemplified by: spraying the ink composition of the present invention onto a substrate through an inkjet head, and then exposing and curing the coating of the ink composition of the present invention on the substrate by light.

[0142] For example, the ejection onto the substrate (image printing) can be carried out by supplying the ink composition of the present invention to a low-viscosity printhead for inkjet printing, and ejecting the ink composition from the printhead onto the substrate in such a way that the film thickness reaches, for example, 1 to 60 μm. Furthermore, exposure and curing under light (image curing) can be carried out by irradiating light onto the film of the ink composition of the present invention, which serves as an image coated onto the substrate.

[0143] As an inkjet printing apparatus for printing the ink composition of the present invention, conventional inkjet printing apparatuses can be used. Furthermore, when using a continuous inkjet printing apparatus, a conductivity-imparting agent can be added to the ink composition of the present invention to adjust the conductivity.

[0144] As a light source for curing the above-mentioned coating, examples include ultraviolet (UV), ultraviolet light (LED), electron beam, visible light, etc. From an environmental perspective, it is preferable to use an ultraviolet light (LED) that produces an ultraviolet light peak in the range of 350~420nm.

[0145] Example

[0146] The following examples illustrate the present invention in further detail, but the present invention is not limited to these examples.

[0147] Active energy ray curable inkjet ink compositions were prepared for each of the examples and comparative examples described in Table 1 below, and the test results related to each active energy ray curable inkjet ink composition are recorded in Table 1.

[0148] PV19: Pigment Violet 19

[0149] PR122: Pigment Red 122

[0150] PR202: Pigment Red 202

[0151] PO71: Pigment Orange 71

[0152] PX4701: Acrylic acid copolymer (EFKAPX4701, BASF)

[0153] S56000: Water-soluble polymeric dispersant (Solsperrse S56000, Lubrizol Corporation, Japan)

[0154] BYKJET-9151: Water-soluble polymeric dispersant (BYKJET-9151, BYK Corporation)

[0155] PB821: Ester dispersant (AJISPER PB821, Ajinomoto Fine-Techno)

[0156] CN371NS: Amine-modified (meth)acrylate oligomer (Sartomer CN371NS, Sartomer Arkema)

[0157] CN373: Amine-modified (meth)acrylate oligomers (Sartomer Arkema)

[0158] Agisyn008: Amine-modified (meth)acrylate oligomers (DSM-Agi)

[0159] Agisyn003: Amine-modified (meth)acrylate oligomer (DSM-Agi)

[0160] TPO: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide

[0161] DETX: 2,4-Diethylthiazolidinone

[0162] MEHQ: Hydroquinone Monomethyl Ether

[0163] UV22: Quinone polymerization inhibitor (BASF)

[0164] BYK377: 100% solids, polyether-modified siloxane surfactant (BYK Corporation)

[0165] (Viscosity)

[0166] The viscosity (cps) of the active energy ray curable inkjet ink compositions obtained in the Examples and Comparative Examples was measured using an E-type viscometer (trade name: RE100L type viscometer, manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25°C and a rotor rotation speed of 20 rpm.

[0167] (Surface tension)

[0168] For each active energy ray curable inkjet ink composition, the surface tension was measured at 25°C using a dynamic wettability testing machine (trade name: WET-6000) manufactured by Rhesca.

[0169] (Red color development)

[0170] (Evaluation of the exhibit) (OD value) (b) value)

[0171] For cured coatings prepared under the same conditions as those prepared to confirm the adhesion described below, the OD value (optical density) and L were measured using an eXact spectrophotometer / concentration meter (manufactured by X-rite). a b Values. The OD values ​​and b in Table 1. The measured values ​​are recorded in the value column.

[0172] In addition, based on OD value and b The measured values ​​are used to evaluate the developing chromophores according to the following standards.

[0173] ○: OD value above 1.30, and b Value between 28 and 32

[0174] ×: OD value below 1.30, or b Values ​​below 28 or above 32

[0175] (Seamless fit)

[0176] Using a #4 coating rod, the active energy radiation-curable inkjet printing ink compositions obtained in the examples and comparative examples were coated onto various substrates (acrylic (Acrylite L, Mitsubishi Rayon), PVC (vinyl chloride sheet) (PVC80, LINTEC), polycarbonate (NF2000 white, Mitsubishi Gas Chemical), PS (polystyrene)). A UV-LED lamp manufactured by Phoseon Technology was used, with a distance of 2 cm between the lamp and the ink coating surface, and each irradiation lasting 1 second (cumulative UV light intensity 60 mJ / cm² per second). 2 Under the conditions described above, the coating is irradiated twice to form a cured film.

[0177] The cured coating film is cut into 100 square pieces using a cutter. Transparent tape (manufactured by Nichiban Corporation, trade name CELLOTAPE (registered trademark)) is applied to each cut portion and then peeled off. The number of square pieces that remain on the substrate without being peeled off the tape is counted. For example, 100 / 100 means none were peeled off, and all pieces remain on the substrate; 20 / 100 means 20 pieces remain on the substrate, and 80 pieces were peeled off from the transparent tape.

[0178] (patience)

[0179] (Pencil hardness)

[0180] The surface of the cured coating obtained for the test of adhesion is evaluated by pencil scratch test (pencil hardness) based on Japanese Industrial Standard (JIS) K5600-5-4.

[0181] (Abrasion resistance)

[0182] Using a #4 coating rod, the active energy radiation-curable ink composition for inkjet printing obtained in the examples and comparative examples was coated onto PVC80 (manufactured by LINTEC). Then, using a UV-LED lamp manufactured by Phoseon Technology, the lamp was placed at a distance of 2 cm from the ink coating surface, with each irradiation lasting 1 second (cumulative UV light intensity of 60 mJ / cm² per second). 2 Under the conditions described above, the coating is irradiated twice to form a cured film.

[0183] Compared to the cured coating, the peeling of the cured coating on PVC80 (LINTEC) after rubbing with 500g of bleached cloth for 50 times was visually observed using a vibration-type friction tester (manufactured by Daiei Scientific Instruments Co., Ltd.), and evaluated according to the following evaluation criteria.

[0184] ○: Even after more than 50 rubs, the cured coating did not peel off.

[0185] △: After 10 to 49 rubs, the cured coating will peel off.

[0186] ×: After rubbing 1 to 9 times, the cured coating will peel off.

[0187] (Water resistance)

[0188] Compared to the cured coating used in the evaluation of abrasion resistance, the peeling of the cured coating on PVC80 (LINTEC) after rubbing the coating with 200g of bleached cloth containing 5 drops of water for 50 times was visually observed using a vibratory abrasion tester (manufactured by Daiei Scientific Instruments Co., Ltd.). The evaluation was carried out according to the following evaluation criteria.

[0189] ○: Even after more than 50 rubs, the cured coating did not peel off.

[0190] △: After 10 to 49 rubs, the cured coating will peel off.

[0191] ×: After rubbing 1 to 9 times, the cured coating will peel off.

[0192] (LED curability)

[0193] At an ambient temperature of 25°C, the inkjet recording device and the active energy radiation-curable inkjet ink composition were placed for 24 hours to maintain a temperature of 25°C. Then, at 25°C, the active energy radiation-curable inkjet ink composition was applied to PVC80 (manufactured by LINTEC) using a #4 coating stick. Finally, it was cured using a UV-LED lamp manufactured by Phoseon Technology.

[0194] The curing performance using UV-LED lamps was evaluated using the following method. The results are shown in Table 1.

[0195] (Curing properties when using UV-LED lamps)

[0196] Using a UV-LED lamp manufactured by Phoseon Technology, with a distance of 2 cm between the lamp and the ink coating surface, and an irradiation time of 1 second per session (cumulative UV light intensity of 60 mJ / cm² per second). 2 The cumulative amount of irradiation energy until the surface viscosity disappears is evaluated.

[0197] [Table 1]

[0198]

[0199]

[0200]

[0201] According to various embodiments that serve as examples of the present invention, the ink composition for active energy ray curable inkjet inks exhibits an appropriate range of viscosity, excellent red color development, adhesion to various substrates, durability, and LED curability.

[0202] In contrast, compared to the total mass of Pigment Violet 19 and Pigment Orange 71, Pigment Violet 19 was not 30.0~85.0% by mass in Comparative Examples 1 and 2, and the evaluation results of the color development were particularly poor. According to Comparative Examples 3 and 4, where neither Pigment Violet 19 nor Pigment Orange 71 was used, the overall red color development was poor.

[0203] Furthermore, according to Comparative Example 5, which does not contain (A) polyfunctional amine modified oligomers, the adhesion to various substrates and LED curing performance are poor. According to Comparative Example 6, which contains excess (A) polyfunctional amine modified oligomers, the active energy ray curable inkjet ink composition becomes highly viscous and has poor adhesion to various substrates.

[0204] Comparative Example 7, which does not contain a polyfunctional monomer with a glass transition temperature of 10°C or less (E), exhibits poor adhesion, abrasion resistance, and water resistance on various substrates. Comparative Example 8, which contains a polyfunctional monomer with an excess of (E) and a glass transition temperature of 10°C or less (E), exhibits insufficient adhesion on various substrates.

[0205] Comparative Example 9, which has a low content of vinylcaprolactam (N-vinylcaprolactam), a nitrogen-containing monofunctional monomer (F), exhibits poor adhesion to various substrates and LED curing properties. Comparative Example 10, which has a high content of nitrogen-containing monofunctional monomer (F), exhibits insufficient adhesion to various substrates.

[0206] Comparative Examples 11 and 12, which contain multifunctional monomers with glass transition temperatures below 10°C but do not contain (E) glass transition temperatures below 10°C, exhibit insufficient adhesion to various substrates.

Claims

1. A composition of ink for inkjet printing that is cured by active energy rays, characterized in that, Contains pigments, pigment dispersants, and photopolymerizing compounds. The pigment contains Pigment Violet 19 and Pigment Orange 71, with Pigment Violet 19 accounting for 30.0% to 85.0% by mass relative to the total mass of Pigment Violet 19 and Pigment Orange 71. Photopolymerizable compounds satisfy all the main conditions (A) to (F) below: (A) Contains polyfunctional amine-modified oligomers accounting for 0.20~15.0% by mass of the total polymerizable components. (B) Contains a monofunctional monomer accounting for more than 50.0% by mass of the total polymerizable components. (C) Contains monofunctional monomers with a glass transition temperature of 20°C or higher, comprising 35.0% to 60.0% by mass of the total polymerizable components. (D) Contains monofunctional monomers with a glass transition temperature of 10°C or lower, comprising 35.0% to 60.0% by mass of the total polymerizable components. (E) Contains 2.0 to 11.0% by mass of a multifunctional monomer with a glass transition temperature below 10°C, in the total amount of polymerizable components. (F) Contains a nitrogen-containing monofunctional monomer in the total amount of polymerizable components, which accounts for 10.0 to 25.0% by mass.

2. The active energy ray curable ink composition for inkjet printing according to claim 1, characterized in that, (A) The polyfunctional amine modified oligomer is a difunctional amine modified oligomer, and its viscosity at 25°C is below 2000 cps.

3. The active energy ray curable ink composition for inkjet printing according to claim 1 or 2, characterized in that, The nitrogen-containing monofunctional monomer is selected from at least one of vinylcaprolactam, N,N-dimethylacrylamide, vinylmethyloxazolidinone and acrylmorpholine.

4. The active energy ray curable ink composition for inkjet printing according to any one of claims 1 to 3, characterized in that, The ink film with an OD value of 1.30 or higher, formed by color development using a #4 coating bar or by inkjet printing to create a solid portion, is b. The value is between 28.0 and 32.0.

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