Photocurable ink composition for inkjet

Abstract

The present invention addresses the problem of providing a photocurable ink jet ink composition which can be reduced in viscosity as an ink jet ink composition, has sufficiently high reactivity, and is capable of reducing the amount of substances that migrate to other surfaces that come into contact with the surface of the cured photocurable ink jet ink composition. As a solution, provided is a photocurable inkjet ink composition characterized by containing the following A-E: A. a polymer photopolymerization initiator containing an ethylenically unsaturated bond; b, a thioxanthone polymer photosensitizer with the molecular weight of 500 or more; c. a (meth) acrylate compound; d. An amine-modified oligomer having a weight average molecular weight of from 500 to 3,000 and a viscosity of less than 4,000 cps; the ratio of A / D is 1 / 9-9 / 1, the total amount of A and D in the ink composition is 5-40%, the content of a photopolymerization initiator having a molecular weight of less than 500 is less than 0.2%, the viscosity is 100 cps or less, and the surface tension is 32.0 mN / m or less.

Description

Technical Field

[0001] The present invention relates to a photocurable inkjet ink composition. Background Art

[0002] There are two types of photocurable inkjet ink compositions: solvent-based ink compositions containing a solvent and solvent-free ink compositions containing no solvent. The solvent-free inkjet ink compositions are generally photocurable inkjet ink compositions.

[0003] When printing is performed using a solvent-based inkjet ink composition, the ink composition needs to be dried or cured after printing. Without such a step, it is difficult to process the printed material in a subsequent processing step.

[0004] In the printing process taking such post-processing into consideration, it is preferred to use a solvent-free material in the photocurable inkjet ink composition. However, in order to quickly process after printing and to allow the photocurable inkjet ink composition to cure immediately, a photopolymerization initiator with particularly high reactivity and low molecular weight is selected as the photopolymerization initiator.

[0005] However, when such a highly reactive low molecular weight photopolymerization initiator is used, there is a possibility that components derived from the photopolymerization initiator, such as unreacted initiator and initiator fragments, migrate from the coating film of the photocurable inkjet ink composition after photocuring.

[0006] To address the above problems, as disclosed in Patent Document 1, there is known an inkjet composition containing a specific acylphosphine oxide compound as a photopolymerization initiator in order to reduce the amount of migration.

[0007] Furthermore, as shown in Patent Document 2, there is known an inkjet ink composition containing a specific compound having an amide bond and a photopolymerization initiator having a molecular weight of 400 to 2,000.

[0008] Furthermore, as shown in Patent Document 3, there is known an inkjet ink composition which contains a polymer initiator having an acylphosphine structure, a polymerizable compound, and a colorant and has little migration.

[0009] Furthermore, it is also known that OMNIPOL TX may be contained as a sensitizer, and tripropylene glycol diacrylate or EO-modified trimethylolpropane triacrylate may be used as a polymerizable compound.

[0010] However, if the composition is one in which the molecular weight of the photopolymerization initiator is increased from the viewpoint of preventing migration to other articles as in the inventions described in these patent documents, the viscosity of the photocurable inkjet ink composition may increase.

[0011] Patent Literature Patent Document 1: International Publication No. 2018-047484 Patent Document 2: Japanese Patent Application Publication No. 2014-240464 Patent Document 3: Japanese Patent Application Publication No. 2014-185319 Summary of the invention The present invention has been made in view of the above circumstances. By making a photocurable inkjet ink composition of a specific composition contain a specific photopolymerization initiator, a photocurable inkjet ink composition can be provided. The photocurable inkjet ink composition can be prepared to have a suitable viscosity as an inkjet ink composition, can achieve sufficiently high reactivity, and can reduce the migration substances generated from the coating film of the cured photocurable inkjet ink composition.

[0012] The present inventors have found that the above-mentioned problems can be solved by preparing the following photocurable inkjet ink composition, and have completed the present invention.

[0013] 1. A photocurable inkjet ink composition, characterized in that it contains the following A to E: A. A polymer photopolymerization initiator containing ethylenically unsaturated bonds; B. Thioxanthone polymer photosensitizer with molecular weight above 500; C. (Meth)acrylate polymerizable compounds; D. an amine-modified photopolymerizable oligomer having a weight average molecular weight of 500 to 3,000 and a viscosity of less than 4,000 cps; E. Surface conditioning agent, The ratio of A / D is 1 / 9 to 9 / 1, the total amount of A and D in the ink composition is 5 to 40%, the content of the photopolymerization initiator with a molecular weight of less than 500 is less than 0.2%, the viscosity is less than 100 cps, and the surface tension is less than 32.0 mN / m.

[0014] 2. The photocurable inkjet ink composition according to item 1, wherein the content of the sensitizer having a molecular weight of less than 500 is less than 0.2%.

[0015] 3. The photocurable inkjet ink composition according to 1 or 2, further comprising a pigment having an average particle size of 500 nm or less.

[0016] According to the present invention, a photocurable inkjet ink composition can be obtained which has sufficiently high reactivity and excellent anti-migration properties sufficient for food packaging applications, and has excellent adhesion to resin films and LED curability and metal halide lamp curability. In particular, even if a polymer initiator is contained, the viscosity can be adjusted to an appropriate level.

[0017] In the present invention, in the printed portion formed by printing and curing the photocurable inkjet ink composition, all components derived from the initiator, including unreacted initiator or initiator fragments, that pass through the substrate and migrate to the simulated food (ethanol aqueous solution) are referred to as migrated components. DETAILED DESCRIPTION

[0018] Hereinafter, the photocurable inkjet ink composition of the present invention (hereinafter sometimes simply referred to as "ink composition" depending on the circumstances) is used for the same purpose as the conventional photocurable inkjet ink composition. In addition, in this specification, the total polymerizable components in the present invention are the monomers and oligomers contained in the ink composition, and are all components that react with each other and polymerize during curing. In addition, "(meth)acrylate" means "acrylate and / or methacrylate", "(meth)acrylamide" means "acrylamide and / or methacrylamide", and "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid".

[0019] Furthermore, the photocurable inkjet ink composition of the present invention is for printing, and is not used for obtaining a three-dimensional object.

[0020] <A. Polymer photopolymerization initiator containing ethylenically unsaturated bonds> The photocurable inkjet ink composition of the present invention contains a polymeric photopolymerization initiator containing an ethylenically unsaturated bond. In addition, in the present invention, the photocurable inkjet ink composition may contain one or more polymeric photopolymerization initiators containing an ethylenically unsaturated bond.

[0021] The ethylenically unsaturated bond possessed by the polymer photopolymerization initiator containing ethylenically unsaturated bonds is one or more bonds selected from (meth) acrylamide, (meth) acrylate, vinyl, vinyl ether, methyl vinyl ether, allyl, (meth) allyl ether and maleimide. In addition, when the polymer photopolymerization initiator containing ethylenically unsaturated bonds contains two or more ethylenically unsaturated bonds, they can be the same or different. Further, as an ethylenically unsaturated bond, it is preferred to have at least one (meth) acrylamide. When the polymer photopolymerization initiator containing ethylenically unsaturated bonds is a free radical photopolymerization initiator, since it contains a (meth) acrylamide group, the absorption wavelength of light can be shifted to the long wavelength side, so high energy and dangerous short wavelength light can be omitted, thereby improving the safety of the photocuring reaction. In addition, since the (meth) acrylamide group has high polymerizability, the photocurability of the photocurable inkjet ink composition containing the (meth) acrylamide group will increase. When used in combination with a substance in which the polymer photopolymerization initiator containing an ethylenically unsaturated bond is a cationic photopolymerization initiator, or a substance in which the polymer photopolymerization initiator containing an ethylenically unsaturated bond is an anionic photopolymerization initiator, since the (meth)acrylamide group has excellent hydrolysis resistance under both acidic and alkaline conditions, the stability of the composition before curing and the durability of the cured product after curing are also good.

[0022] The free radical photopolymerization initiating functional group used in the polymer photopolymerization initiator containing an ethylenically unsaturated bond is a substance that generates active free radicals by light irradiation, and preferably has a hydrogen abstraction type free radical photopolymerization initiating functional group that exists in the cured product as a structural unit through a covalent bond after the photopolymerization reaction. These photopolymerization initiating functional groups can be used alone or in combination of two or more.

[0023] Furthermore, a thioxanthone-based polymer photopolymerization initiator may or may not be used in combination.

[0024] The radical photopolymerization initiating functional group used in the polymer photopolymerization initiator containing an ethylenically unsaturated bond may be a hydrogen abstraction type photopolymerization initiating functional group, and may be a group derived from a benzophenone derivative having a diaryl ketone skeleton, such as benzophenone, alkyldiaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide. In addition, from the perspective of having both high photopolymerization initiation and good coloration resistance, a group derived from benzophenone is preferred. These photopolymerization initiating functional groups may be used alone or in combination of two or more.

[0025] When the polymer photopolymerization initiator containing an ethylenically unsaturated bond has a hydrogen-abstracting free radical photopolymerization initiating functional group, it is preferred that the molecule has a functional group that can become a hydrogen-donating group. There is no particular limitation on the functional group that can become a hydrogen-donating group, and examples thereof include: an amide group, a carbamate group, a urea group, a hydroxyl group, a thiol group, a carboxylic acid, etc. Among them, a carbamate group having excellent color fastness is more preferred. In addition, the functional group that can become a hydrogen-donating group can be directly bonded to the photopolymerization initiating functional group, but when bonded through other functional groups, hydrogen abstraction can occur between or within the molecule, and sufficient polymerization initiation is also shown to long-wavelength light with high safety from a wavelength of 360nm, so it is particularly preferred.

[0026] The polymer photopolymerization initiator containing an ethylenically unsaturated bond has: one or more divalent organic groups having a polyether skeleton and a urethane bond and a benzophenone skeleton bonded to the organic group as repeating units, and one or more (meth)acrylamide units bonded to the repeating units. The interaction between the flexibility of the polyether skeleton and the toughness of the urethane bond can make the ink composition and the coating film after curing have excellent adhesion to the resin film. In addition, the molecular weight of the polymer photopolymerization initiator can be easily adjusted, and the viscosity of the ink composition can also be appropriately adjusted. The present invention is based on the effect that the ink composition and the coating film after curing have excellent adhesion to the resin film.

[0027] The molecular weight of the polymer photopolymerization initiator containing an ethylenically unsaturated bond is preferably 1,000 to 100,000 in terms of number average molecular weight. Furthermore, if the number average molecular weight is 1,000 or more, even if unreacted initiator remains, migration will not occur. In addition, if the number average molecular weight is 100,000 or less, it is easy to adjust the polarity (balance between hydrophilicity and hydrophobicity) of the obtained photopolymerization initiator, and the solubility of each component used in the photocurable inkjet ink composition is high. The viscosity of the composition in which the polymer photopolymerization initiator containing an ethylenically unsaturated bond is dissolved can be controlled within a range suitable for various operations such as coating, spraying, and extrusion, and the transparency of the photocurable inkjet ink composition can also be ensured.

[0028] The content of the high molecular weight photopolymerization initiator containing an ethylenically unsaturated bond in the ink composition is 1.0 to 40.0% by mass, more preferably 1.5% by mass or more, and even more preferably 5.0% by mass or more. In addition, it is preferably 37.0% by mass or less, and more preferably 30.0% by mass or less.

[0029] In addition, the polymer photopolymerization initiator containing an ethylenically unsaturated bond in the present invention has one or more ethylenically unsaturated bonds and one or more photopolymerization initiating functional groups in the molecule. In addition, from the perspective of improving the photopolymerization initiability and photocurability to long-wavelength light, and from the perspective of being able to enter the cured product through covalent bonds after photopolymerization initiation, it is preferred that the molecule has two or more ethylenically unsaturated bonds. Furthermore, the number ratio of the ethylenically unsaturated bonds (groups) in the molecule to the number ratio of the photopolymerization initiating functional groups (the number ratio of the ethylenically unsaturated groups to the number ratio of the photopolymerization initiating functional groups) is preferably 1 / 10 to 10 / 1, more preferably 1 / 8 to 8 / 1, and particularly preferably 1 / 5 to 5 / 1. When the number ratio is less than 0.1 (1 / 10), although it also depends on the content of the photopolymerization initiator in the photocurable inkjet ink composition, the photopolymerization rate of the photocurable inkjet ink composition may be significantly accelerated. On the other hand, when the number ratio exceeds 10.0 (10 / 1), even if the photopolymerization initiator completes the photopolymerization reaction (curing), it will not be fixed in the cured product as a structural unit through a covalent bond. Although the result also depends on the molecular weight of the photopolymerization initiator, a low-molecular-weight photopolymerization initiator exists in the cured product as a free low-molecular weight, so there is a risk that the odor problem of the cured product or the problem of easy coloration over time will not be fully solved.

[0030] The polymer photopolymerization initiator containing an ethylenically unsaturated bond in the present invention is a high molecular weight compound having one or more ethylenically unsaturated groups and photopolymerization initiating groups, and regardless of the polymer structure other than these groups, each group must be contained in one polymer. By having such a structure, the effect of the present invention can be exerted.

[0031] The free radical photopolymerization initiating functional group used in the polymer photopolymerization initiator containing an ethylenically unsaturated bond in the present invention is not particularly limited as long as it is a functional group that generates active free radicals by light irradiation. For example, hydrogen-abstracting type and electron-donating type free radical photopolymerization initiating functional groups that generate free radicals by exchanging hydrogen or electrons after light absorption can be cited. In addition, from the perspective of being present in the cured product as a structural unit through a covalent bond after the photopolymerization reaction and from the perspective of being easy to obtain or manufacture industrially, the photopolymerization initiator preferably has a hydrogen-abstracting type free radical photopolymerization initiating functional group. These photopolymerization initiating functional groups can be used alone or in combination of two or more.

[0032] The polymer photopolymerization initiator containing an ethylenically unsaturated bond in the present invention can be synthesized by referring to the method described in Japanese Patent No. 7016199.

[0033] Furthermore, as an example of the polymer photopolymerization initiator containing an ethylenically unsaturated bond in the present invention, there are shown those having the ethylenically unsaturated groups, the number of ethylenically unsaturated groups / the number of benzophenone groups, and the number average molecular weight shown in Table 1 below.

[0034] [Table 1]

[0035] The polymer photopolymerization initiator containing an ethylenically unsaturated bond may be used in combination or not, and is not particularly limited as long as it is a substance that can initiate polymerization by receiving active energy rays, within the range that does not impair the effects of the present invention. A polymer photopolymerization initiator different from the polymer photopolymerization initiator containing an ethylenically unsaturated bond used in a conventional photocurable inkjet ink composition, or a photopolymerization initiator that is not a polymer, may be used.

[0036] Examples of such photopolymerization initiators include benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketone photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, triazine photopolymerization initiators, and acylphosphine oxide photopolymerization initiators. Among these, triazine photopolymerization initiators and acylphosphine oxide photopolymerization initiators are preferred from the perspective of good curability to light from a light emitting diode (LED). The aforementioned photopolymerization initiators may be used alone or in combination of two or more.

[0037] Examples of such photopolymerization initiators include phenyl (2,4,6-trimethylbenzoyl) phosphinic acid glycerolethoxylated triester (Omnipol-TP (IGM Resins BV)), bis (2,4,6-trimethylbenzoyl) phenyl phosphine oxide, ethoxy (2,4,6-trimethylbenzoyl) phenyl phosphine oxide, benzophenone, diethyl thioxanthone, 2-methyl-1-(4-methylthio) phenyl-2-morpholinopropane-1-one, 4-benzoyl-4'-methyldiphenyl sulfide, 1-chloro-4-propoxy thioxanthone, isopropyl thioxanthone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclopentane Hexyl phenyl 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. In addition, a thioxanthone-based polymer photopolymerization initiator may or may not be used in combination.

[0038] Here, as a non-polymer photopolymerization initiator, the content of the photopolymerization initiator having a molecular weight of less than 500 is preferably set to less than 0.20% by mass, more preferably less than 0.15% by mass, and further preferably less than 0.10% by mass. By reducing the content of the photopolymerization initiator having a molecular weight of less than 500, the content of low molecular weight components in the ink composition layer after photocuring can be reduced, thereby suppressing the occurrence of migration.

[0039] In addition, a polymer photopolymerization initiator other than the polymer photopolymerization initiator containing an ethylenically unsaturated bond in the present invention may be used in combination or not. Such a polymer photopolymerization initiator is a substance having a number average molecular weight of 450 or more, and examples thereof include polymer compounds having a benzoyl group, a phosphono group, an acyl oxime group, etc., compounds having a low molecular photopolymerization initiator bonded to a skeleton of a polyether structure or a polyester structure, polymers of low molecular photopolymerization initiators (Keycure POL-8150 (UV Chem-keys)), and photopolymerizable polymer compounds bonded to low molecular photopolymerization initiators (LoMicure 450 (BCH Bruhl Chemikalien Handel)).

[0040] Specific examples of the polymer initiator include poly(oxy-1,2-ethanediyl)α-(1-oxo-2-propenyl)-ω-(4-benzoyl-phenoxy)- and oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone.

[0041] <B. Thioxanthone-based polymer photosensitizers with a molecular weight of 500 or more> Examples of thioxanthone-based polymeric photosensitizers having a molecular weight of 500 or more include Omnipol-TX ((2-carboxymethoxythioxanthone)-(polytetramethylene glycol 250) diester) (number average molecular weight: 660) (manufactured by IGM Resins BV) and Genopol TX-1 (number average molecular weight: 820) (manufactured by RaHN).

[0042] The active energy ray-curable inkjet ink composition preferably contains a thioxanthone polymer photosensitizer having a molecular weight of 500 or more in an amount of 0.05 to 10.0 parts by mass relative to 100 parts by mass of the total amount of all polymerizable components. The amount is more preferably 0.1 parts by mass or more, further preferably 0.2 parts by mass or more, more preferably 8.0 parts by mass or less, further preferably 6.0 parts by mass or less.

[0043] (Other polymer sensitizers) Other polymer sensitizers can be used in the present invention. Examples of acylphosphine polymer sensitizers include SpeedCure 7010 (molecular weight 1839) (manufactured by Lambson), oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)acetone) (manufactured by Lamberti, "ESACURE KIP 150", "ESACURE 1"), polyethylene glycol 200-bis(β-4(4-(2-dimethylamino-2-benzyl)butanoylphenyl)piperazine) (manufactured by IGM, "Omnipol 910"), (carboxymethoxymethoxybenzophenone)-(polyethylene glycol 250) diester (manufactured by IGM, "Omnipol BP"), etc. These can be used alone or in combination.

[0044] In the present invention, by containing a polymer sensitizer, the curing property can be improved in synergy with the polymer polymerization initiator, and by making the polymer sensitizer difficult to migrate, the volatile components or migrating components remaining after curing can be reduced.

[0045] (Other photosensitizers) The present invention may or may not contain other non-polymeric sensitizers within a range not impairing the effects thereof. In addition, the thioxanthone-based photosensitizers may be used alone or in combination of two or more.

[0046] Examples of thioxanthone-based photosensitizers include 2,4-diethylthioxanthone, 2,4-diethylthioxan-9-one, 2-isopropylthioxanthone, and 4-isopropylthioxanthone. Examples of thioxanthone-based photosensitizers include trade names such as “DETX” (2,4-diethylthioxanthone) and “ITX” (Lambson Corporation).

[0047] In addition, for example, as anthracene sensitizers such as 9,10-dibutoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, and 9,10-bis(2-ethylhexyloxy)anthracene, trade names "DBA" and "DEA" (above, Kawasaki Chemical Industries, Ltd.) can be cited. In addition to the above, Omnirad EDB diethylaminobenzoic acid ethyl ester (IGM RESINS B.V.) can also be used.

[0048] In addition, aminobenzoic acid ester compounds can also play the same role as (meth)acrylamide compounds even as sensitizers.

[0049] From the perspective of preventing excessive addition, when other sensitizers are contained, within the range not impairing the effects of the present invention, 0.3 to 10.0 parts by mass of other photosensitizers may be contained based on 100 parts by mass of the total photopolymerizable component. Furthermore, 1.0 parts by mass or more may be contained, or 9.0 parts by mass or less may be contained.

[0050] Here, as other photosensitizers, the content of a sensitizer having a molecular weight of less than 500 is preferably less than 0.20% by mass, more preferably less than 0.15% by mass, and further preferably less than 0.10% by mass. By reducing the content of such a sensitizer having a molecular weight of less than 500, the content of low molecular weight components in the ink composition layer after photocuring can be reduced, thereby suppressing the occurrence of migration.

[0051] <C. (Meth)acrylate polymerizable compound> The (meth)acrylate polymerizable compound C in the present invention is one type of photopolymerizable compound, and one or more of the following compounds may be used. In addition, the following D. amine-modified photopolymerizable oligomer is not included.

[0052] C. (meth)acrylate polymerizable compounds include, in terms of monomers, monofunctional (meth)acrylate polymerizable compounds and polyfunctional (meth)acrylate polymerizable compounds.

[0053] The content of C. (meth)acrylate polymerizable compound in the total photopolymerizable components is preferably 50.0 mass % or more, more preferably 60.0 mass % or more, and further preferably 65.0 mass % or more. It is preferably 97.0 mass % or less, more preferably 95.0 mass % or less, and further preferably 90.0 mass % or less.

[0054] (Monofunctional (meth)acrylate polymerizable compound) Examples of the monofunctional (meth)acrylate polymerizable compound include alkyl (meth)acrylate compounds, hydroxyl group-containing (meth)acrylate compounds, halogen-containing (meth)acrylate compounds, ether group-containing (meth)acrylate compounds, carboxyl group-containing (meth)acrylate compounds, and other (meth)acrylate compounds.

[0055] In the present invention, the content of the monofunctional (meth)acrylate polymerizable compound in the total photopolymerizable component is preferably 15.0 mass % or more, more preferably 20.0 mass % or more, and further preferably 25.0 mass % or more. In addition, it is preferably 70.0 mass % or less, more preferably 65.0 mass % or less, and further preferably 60.0 mass % or less.

[0056] -(Meth)acrylic acid alkyl ester compounds- Examples of the alkyl (meth)acrylate compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, and t-butyl (meth)acrylate. Isooctadecyl acrylate, isodecyl (meth)acrylate, isomyristyl (meth)acrylate, dicyclopentyl (meth)acrylate, tridecyl (meth)acrylate, nonyl (meth)acrylate, hexadecyl (meth)acrylate, myristyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 1-adamantyl (meth)acrylate, 3,5,5-trimethylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, etc.

[0057] When the photocurable inkjet ink composition of the present invention contains a monofunctional alkyl (meth)acrylate compound, the content thereof in the total photopolymerizable components is preferably 10.0% by mass or more, more preferably 12.0% by mass or more, and further preferably 15.0% by mass or more. In addition, it is preferably 85.0% by mass or less, more preferably 80.0% by mass or less, and further preferably 75.0% by mass or less.

[0058] -Hydroxy-containing (meth)acrylate compounds- Examples of the hydroxyl group-containing (meth)acrylate compounds include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, 2-hydroxy-3-methoxypropyl (meth)acrylate, 2-hydroxy-3-butoxypropyl (meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate. (meth)acrylate, 1,6-hexanediol mono(meth)acrylate, glycerol mono(meth)acrylate, 2-hydroxy-3-chloropropyl(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, 2-hydroxy-3-allyloxypropyl(meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropylphthalate, 2-ethylhexyl EO-modified(meth)acrylate, o-phenylphenol EO-modified(meth)acrylate, p-cumylphenol EO-modified(meth)acrylate, nonylphenol EO-modified(meth)acrylate, and the like (poly)alkylene glycol-modified(meth)acrylates, etc. In the present invention, it is preferred to contain a hydroxyl group-containing(meth)acrylate compound, and it is more preferred to contain a hydroxyalkyl(meth)acrylate.

[0059] The content of the hydroxyl-containing (meth)acrylate compound in the total polymerizable components is preferably 20.0% by mass or more, more preferably 25.0% by mass or more, and further preferably 30.0% by mass or more. In addition, it is preferably 65.0% by mass or less, more preferably 60.0% by mass or less, and further preferably 55.0% by mass or less.

[0060] -Halogen-containing (meth)acrylate compounds- Examples of the halogen-containing (meth)acrylate compounds include trifluoromethyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H-hexafluoroisopropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, 1H,1H,2H,2H-heptadecafluorodecyl (meth)acrylate, 2,6-dibromo-4-butylphenyl (meth)acrylate, 2,4,6-tribromophenoxyethyl (meth)acrylate, and 2,4,6-tribromophenol 3EO (ethylene oxide) addition (meth)acrylate.

[0061] -Ether group-containing (meth)acrylate compounds- Examples of the ether group-containing (meth)acrylate compounds include 1,3-butanediol methyl ether (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, ethylcarbitol (meth)acrylate, 2-ethylhexylcarbitol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, tolylpolyethylene glycol (meth)acrylate, and (meth)acrylate- 2-(vinyloxyethoxy)ethyl acrylate, phenoxyethyl (meth)acrylate, p-nonylphenoxyethyl (meth)acrylate, p-nonylphenoxypolyethylene glycol (meth)acrylate, glycidyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxy-polyethylene glycol (meth)acrylate, hexaethylene glycol monophenyl ether mono(meth)acrylate, diethylene glycol monobutyl ether acrylate, dipropylene glycol monomethyl ether (meth)acrylate, 3-methoxybutyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methyl oxypropylene glycol (meth)acrylate, methoxy polyethylene glycol (meth)acrylate (EO repeating unit number 400, 700, etc.), 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl acrylate, ethoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, alkoxylated 2-phenoxyethyl (meth)acrylate (ethoxylated 2-phenoxyethyl ( Alkoxy and / or phenoxy (meth)acrylates such as ethoxylated nonylphenyl (meth)acrylate (ethoxylated (4) nonylphenol (meth)acrylate, etc.), 2-phenoxyethyl (meth)acrylate, p-cumylphenoxyglycol (meth)acrylate, methylphenoxyethyl (meth)acrylate, ethoxylated succinic acid (meth)acrylate, ethoxylated tribromophenyl (meth)acrylate, ethoxylated nonylphenyl (meth)acrylate, etc.

[0062] -Carboxyl-containing (meth)acrylate compounds- Examples of the carboxyl group-containing (meth)acrylate compounds include β-carboxyethyl (meth)acrylate, monoacryloxyethyl succinate, ω-carboxypolycaprolactone mono(meth)acrylate, 2-(meth)acryloxyethyl hydrogen phthalate, 2-(meth)acryloxypropyl hydrogen phthalate, 2-(meth)acryloxypropyl hexahydro hydrogen phthalate, and 2-(meth)acryloxypropyl tetrahydro hydrogen phthalate.

[0063] -Other (meth)acrylate compounds- Examples of other (meth)acrylate compounds include benzyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, morpholinylethyl (meth)acrylate, trimethylsilyloxyethyl (meth)acrylate, diphenyl-2-(meth)acryloyloxyethyl phosphate, 2-(meth)acryloyloxyethyl acid phosphate, caprolactone-modified 2-(meth)acryloyloxyethyl acid phosphate, and 2- Hydroxy-1-(meth)acryloyloxy-3-methacryloyloxypropane, (meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, 2-(meth)acryloyloxypropyl phthalate, tricyclodecane monohydroxymethyl (meth)acrylate, (meth)acrylic acid dimer, diethylaminoethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)hexahydrophthalate ) acryloyloxyethyl ester, 2-ethylhexyl-diglycol (meth)acrylate, aminoethyl (meth)acrylate, ethylcarbitol (meth)acrylate, ethyl diglycol (meth)acrylate, dimethylaminoethyl (meth)acrylate benzyl chloride quaternary salt, tribromophenyl (meth)acrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, cresol (meth)acrylate, trimethylolpropane methylal (meth)acrylate, neopentyl glycol (meth)acrylate benzoate, ( methyl meth)acrylate, 1-(methyl)acryloylpiperidin-2-one, 2-(methyl)acrylate-1,4-dioxaspiro[4,5]deca-2-ylmethyl ester, N-(methyl)acryloyloxyethyl hexahydrophthalimide, γ-butyrolactone (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, imide (meth)acrylate, vinyl (meth)acrylate, maleimide, etc.

[0064] (Multifunctional polymerizable compound) As the polyfunctional polymerizable compound (a compound having two or more unsaturated bonds), for example, the following polyfunctional (meth)acrylate compounds or vinyl ether group-containing (meth)acrylate compounds can be used.

[0065] -Multifunctional (meth)acrylate compounds- As the polyfunctional (meth)acrylate compound, polyethylene glycol di(meth)acrylate such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol (400) di(meth)acrylate, polyethylene glycol (600) di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, pentanediol di(meth)acrylate, etc. can be used. , neopentyl glycol di(meth)acrylate, hydroxypivaloyl hydroxypivalate di(meth)acrylate, hydroxypivaloyl hydroxypivalate dicaprolactone di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,2-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, 1,10-decanediol di(meth)acrylate (Meth)acrylate, 1,2-decanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, 1,2-dodecanediol di(meth)acrylate, 1,14-tetradecanediol di(meth)acrylate, 1,2-tetradecanediol di(meth)acrylate, 1,16-hexadecanediol di(meth)acrylate, 1,2-hexadecanediol di(meth)acrylate, 2-methyl-2,4-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2-methyl-2-propyl-1,3-propanediol di(meth)acrylate 2,4-dimethyl-2,4-pentanediol di(meth)acrylate, 2,2-diethyl-1,3-propanediol di(meth)acrylate, 2,2,4-trimethyl-1,3-pentanediol di(meth)acrylate, dimethylol octane di(meth)acrylate, 2-ethyl-1,3-hexanediol di(meth)acrylate, 2,5-dimethyl-2,5-hexanediol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 2,4-diethyl-1,Alkylene glycol di(meth)acrylates such as 5-pentanediol di(meth)acrylate, tricyclodecane dimethylol di(meth)acrylate, tricyclodecane dimethylol dicaprolactone di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and dicyclopentyl di(meth)acrylate, bisphenol A tetraethylene oxide adduct di(meth)acrylate, bisphenol F tetraethylene oxide adduct di(meth)acrylate, bisphenol S tetraethylene oxide adduct di(meth)acrylate, hydrogenated bisphenol A Tetraethylene oxide adduct di(meth)acrylate, hydrogenated bisphenol F tetraethylene oxide adduct di(meth)acrylate, hydrogenated bisphenol A di(meth)acrylate, hydrogenated bisphenol F di(meth)acrylate, bisphenol A tetraethylene oxide adduct dicaprolactone di(meth)acrylate, bisphenol F tetraethylene oxide adduct dicaprolactone di(meth)acrylate, etc., bifunctional monomers such as di(meth)acrylates of polyols such as glycerol, pentaerythritol, diglycerol, ditrimethylolpropane and dipentaerythritol, etc. Among these multifunctional (meth)acrylate compounds, polyalkylene glycol di(meth)acrylate is preferred, dialkylene glycol di(meth)acrylate is more preferred, and dipropylene glycol di(meth)acrylate is further preferred. ,

[0066] In addition, trifunctional monomers such as glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane tricaprolactone tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolhexane tri(meth)acrylate, trimethyloloctane tri(meth)acrylate, and pentaerythritol tri(meth)acrylate can be mentioned; and 3EO (ethylene oxide)-modified products thereof, 6EO-modified products, 9EO-modified products (EO-modified trimethylolpropane tri(meth)acrylate, 3EO-modified trimethylolpropane tri(meth)acrylate, 3EO-modified trimethylolethane tri(meth)acrylate, 3EO-modified trimethylolhexane tri(meth)acrylate, etc.), pentaerythritol tetra(meth)acrylate, etc. Monomers having four or more functions, such as acrylate, pentaerythritol tetracaprolactone tetra(meth)acrylate, diglycerol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ditrimethylolpropane tetracaprolactone tetra(meth)acrylate, ditrimethylolethane tetra(meth)acrylate, ditrimethylolbutane tetra(meth)acrylate, ditrimethylolhexane tetra(meth)acrylate, ditrimethyloloctane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth)acrylate, and tripentaerythritol polyoxyalkylene hepta(meth)acrylate; etc. Among these, trimethylolpropane triacrylate (TMPTA; 3-functional), ditrimethylolpropane tetraacrylate (DITMPTA; 4-functional), dipentaerythritol hexaacrylate (DPHA; 6-functional), hexanediol diacrylate (HDDA; 2-functional), and the like can be used.

[0067] -(Meth)acrylate compounds containing vinyl ether groups- Examples of the (meth)acrylate compounds containing a vinyl ether group include 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 1-methyl-3-vinyloxypropyl (meth)acrylate, 1-vinyloxymethylpropyl (meth)acrylate, 2-methyl-3-vinyloxypropyl (meth)acrylate, 3-methyl-3-vinyloxypropyl (meth)acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth)acrylate, 3-vinyloxybutyl (meth)acrylate, 1-methyl-2-vinyloxypropyl (meth)acrylate, 2-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 5-vinyloxypentyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, and 1,1-dimethyl-2-vinyloxyethyl (meth)acrylate. 4-vinyloxymethylcyclohexylmethyl acrylate, 3-vinyloxymethylcyclohexylmethyl (meth)acrylate, 2-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenylmethyl (meth)acrylate, m-vinyloxymethylphenylmethyl (meth)acrylate, o-vinyloxymethylphenylmethyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxy)propyl (meth)acrylate, 2-(vinyloxyethoxy)isopropyl acrylate, 2-(vinyloxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxyisopropoxy)ethyl (meth)acrylate, and the like.

[0068] Among these polyfunctional polymerizable compounds, ether group-containing (meth)acrylate compounds or (poly)alkylene glycol di(meth)acrylates are preferred. Among the ether group-containing (meth)acrylate compounds, at least one selected from EO-modified trimethylolpropane triacrylate and 3EO-modified trimethylolpropane triacrylate is preferred.

[0069] Among them, it is more preferred to contain PO-modified neopentyl glycol diacrylate and / or EO-modified trimethylolpropane triacrylate and / or 3EO-modified trimethylolpropane triacrylate and dipropylene glycol diacrylate, and it is most preferred to contain PO-modified neopentyl glycol diacrylate and dipropylene glycol diacrylate.

[0070] In addition, EO modification means ethylene oxide modification, and PO modification means propylene oxide modification.

[0071] The content of the polyfunctional (meth)acrylate compound that can be contained in the photocurable inkjet ink composition of the present invention is preferably 15.0% by mass or more, more preferably 20.0% by mass or more, and further preferably 25.0% by mass or more, relative to the total amount of the photopolymerizable component. In addition, it is preferably 55.0% by mass or less, more preferably 50.0% by mass or less, and further preferably 45.0% by mass or less.

[0072] When the photocurable inkjet ink composition of the present invention contains dipropylene glycol diacrylate and PO-modified neopentyl glycol diacrylate, the mass ratio of dipropylene glycol diacrylate to PO-modified neopentyl glycol diacrylate is preferably 1 / 10 to 10 / 1, more preferably 3 / 7 to 7 / 3, and further preferably 4 / 6 to 6 / 4.

[0073] ((Meth)acrylamide compounds) The photocurable inkjet ink composition of the present invention may contain a (meth)acrylamide compound or may not contain it. Examples of the (meth)acrylamide compound include acryloylmorpholine, (meth)acrylamide, N-isopropyl (meth)acrylamide, and N-(2-hydroxyethyl) (meth)acrylamide. Among them, acryloylmorpholine is preferred.

[0074] In addition, these (meth)acrylamide compounds may be compounds that repeat with the above-mentioned (meth)acrylate compounds, etc. In the case of repeating, it is generally considered to correspond to each compound.

[0075] The content of the (meth)acrylamide compound when contained is preferably 2.0% by mass or more, more preferably 4.0% by mass or more, and further preferably 6.0% by mass or more relative to the total photopolymerizable component. In addition, it is preferably 20.0% by mass or less, more preferably 18.0% by mass or less, and further preferably 15.0% by mass or less.

[0076] <D. Amine-modified photopolymerizable oligomer> The amine-modified photopolymerizable oligomer has a weight average molecular weight of 500 to 3,000 and a viscosity of less than 4,000 cps. In addition, an amine-modified photopolymerizable oligomer including an acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule can be used.

[0077] The amine-modified photopolymerizable oligomer is not particularly limited as long as it is an acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule. For example, the photopolymerizable functional group in the acrylated amine compound can be a functional group that can form a cross-linked bond between molecules by polymerization reaction by visible light or invisible light including ionizing radiation such as ultraviolet rays or electron beams. In addition, the photopolymerizable functional group includes the following two types: a photopolymerizable functional group in a narrow sense that undergoes photopolymerization reaction by direct activation by light irradiation; and a photopolymerizable functional group in a broad sense that initiates polymerization reaction and is promoted by the action of active species generated by the photopolymerization initiator when the photopolymerizable functional group coexists with a photopolymerization initiator and is irradiated with light.

[0078] The photopolymerizable functional group is a functional group with free radical photopolymerization reactivity such as an olefinic double bond, a functional group with cationic photopolymerization and anionic photopolymerization reactivity such as a cyclic ether group such as an epoxy group, etc. Among them, the photopolymerizable functional group is preferably an olefinic double bond such as a (meth) acryloyl group, a vinyl group, an allyl group, and more preferably a (meth) acryloyl group. In the acrylic amine compound having two photopolymerizable functional groups and two amino groups in the molecule, the two photopolymerizable functional groups are both (meth) acryloyl groups, and the amine value is preferably 130~142mgKOH / g. In addition, in the present embodiment, the amine value refers to the amine value per 1g of the solid component, which is measured using a 0.1N hydrochloric acid aqueous solution by potentiometric titration (for example, COMTITE (AUTO TITRATORCOM-900, BURETB-900, TITSTATION K-900), manufactured by Hiranuma Industry Co., Ltd.), and then converted to a value equivalent to potassium hydroxide.

[0079] 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. The bifunctional (meth)acrylate includes 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-butanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate, di(meth)acrylates of ethylene oxide adducts of bisphenol A, and di(meth)acrylates of ethylene oxide adducts of bisphenol F. Bisphenol alkylene oxide adduct di(meth)acrylates such as bisphenol S ethylene oxide adduct di(meth)acrylate, bisphenol S ethylene oxide adduct di(meth)acrylate, bisphenol S ethylene oxide adduct di(meth)acrylate, bisphenol A bromide ethylene oxide adduct di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, etc., di(meth)acrylate of hydroxypivalic acid neopentyl glycol ester, etc. Among these, the bifunctional (meth)acrylate is preferably 1,6-hexanediol di(meth)acrylate.

[0080] The amine compound includes monofunctional amine compounds such as benzylamine, phenylethylamine, 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, and polyfunctional amine compounds such as diethylenetriamine, triethylenetetramine, 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 diamine. Furthermore, the amine compound may be a high molecular weight type polyfunctional amine compound such as polyethyleneimine, polyvinylamine, polyallylamine, or the like.

[0081] As the oligomer of the acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule, CN371NS, CN549NS, CN550, CN551NS, CN371, CN373, CN383, CN386, CN501, CN503, CN3755 (Sartomer), EBECRYL LEO 10101, EBECRYL LEO 10103, EBECRYL80, EBECRYL81, EBECRYL83, EBECRYL7100, EBECRYL84, EBECRYLP115 (Daicel allnex), ETERCURE63922 (Eternal), LAROMER PO 83F, LAROMER PO 84F, Laromer LR8946, Laromer LR8956, Laromer LR8996, Laromer LR8894 (BASF), AgiSyn 001, 002, 003, 008, 701, 701P, 703 and 703TF (DSM), Photomer4771, 4775, 4967, 5096, 5662, 5930 (Cognis), PHOTOCRYLA104, Miramer AS1000 (MIWON), Doublecure EPD, OPD, 115, 225, 645, PolyQ222, 226, 224, 101 (DoubleBondChemicals), etc.

[0082] The amine-modified photopolymerizable oligomer is preferably 3.0% by mass or more, more preferably 4.0% by mass or more, and further preferably 5.0% by mass or more, relative to the total photopolymerizable component, and is preferably 26.0% by mass or less, more preferably 24.0% by mass or less, and further preferably 22.0% by mass or less.

[0083] If the content of the amine-modified photopolymerizable oligomer is less than 3.0 mass %, LED curability and metal halide lamp curability may be poor.

[0084] <E. Surface Conditioning Agent (Surfactant)> In the photocurable inkjet ink composition of the present invention, a known surfactant that can be used in the photocurable inkjet ink composition can be used as a surface conditioner without particular limitation, depending on the inkjet head used or the printed material, and examples thereof include nonionic surfactants, cationic surfactants, anionic surfactants, and betaine surfactants. Specific examples of the aforementioned surfactants include silicone-based surfactants such as polyether-modified silicone oils, polyester-modified polydimethylsiloxanes, and polyester-modified methylalkylpolysiloxanes, fluorine-based surfactants, and acetylene-based surfactants. The aforementioned surfactants can be used alone or in combination of two or more.

[0085] Examples of the silicone-based surfactant 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 Chemie).

[0086] Examples of the fluorine-based surfactant include F-410, F-444, and F-553 (DIC Corporation), FS-65, FS-34, FS-35, FS-31, and FS-30 (Du Pont Corporation).

[0087] Examples of the acetylene surfactant 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 (Nissin Chemical Co., Ltd.), SURFYNOL104E, SURFYNOL104H, SURFYNOL104A, SURFYNOL104BC, SURFYNOL104DPM, SURFYNOL104PA, SURFYNOL104PG-50, SURFYNOL420, SURFYNOL440, SURFYNOL465 (EVONIK Co., Ltd.), etc.

[0088] In the photocurable inkjet ink composition of the present invention, the proportion of the above-mentioned surfactant is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, from the viewpoint of reducing the surface tension of the ink composition and improving the ejection stability from the inkjet head, and is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, from the viewpoint of suppressing the foam in the ink composition generated during the preparation process and improving the ejection stability.

[0089] When a surface conditioner is contained, the content of the surface conditioner is not particularly limited, but is preferably such that the surface tension of the photocurable inkjet ink composition is 32.0 mN / m or less. If the surface tension exceeds 32.0 mN / m, the wettability to the substrate is insufficient, resulting in poor image quality.

[0090] [Other polymerizable compounds] -Unsaturated carboxylic acid compounds- Examples of the unsaturated carboxylic acid-based compound include unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, crotonic acid, isocrotonic acid, fumaric acid, and maleic acid, and salts thereof and anhydrides thereof.

[0091] (Vinyl compounds) In the photocurable inkjet ink composition of the present invention, a vinyl compound may be formulated in addition to the above-mentioned photopolymerizable component. Such a vinyl compound is a vinyl compound having no structure derived from (meth)acrylic acid, and examples thereof include N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, N-vinyl-2-caprolactam, N-vinylcarbazole, and vinylmethyloxazolidinone.

[0092] When a vinyl compound is contained, the content of the vinyl compound is preferably 1.0% by mass or more, more preferably 3.0% by mass or more, and further preferably 5.0% by mass or more relative to the total photopolymerizable component. In addition, it is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and further preferably 6.0% by mass or less.

[0093] -Styrene compounds- Examples of the styrene-based compound include styrene, vinyltoluene, p-hydroxystyrene, p-chlorostyrene, p-bromostyrene, p-methylstyrene, p-methoxystyrene, p-tert-butoxystyrene, p-tert-butoxycarbonylstyrene, p-tert-butoxycarbonyloxystyrene, 2,4-diphenyl-4-methyl-1-pentene, and divinylbenzene.

[0094] -Aryl compounds- Examples of the arylate compound include allyl glycidyl ether, diallyl phthalate, triallyl trimellitate, and triaryl isocyanurate.

[0095] -Other compounds having one ethylenically unsaturated bond- As the compound having one ethylenically unsaturated bond, “other compounds having one ethylenically unsaturated bond” other than the above-mentioned compounds may be used.

[0096] Examples of such compounds include vinyl acetate, vinyl chloroacetate, vinyl benzoate, vinyl pivalate, vinyl butyrate, vinyl laurate, divinyl adipate, vinyl crotonate, vinyl 2-ethylhexanoate, three-membered ring compounds (e.g., vinyl cyclopropanes, 1-phenyl-2-vinylcyclopropanes, 2-phenyl-3-vinyloxiranes, 2,3-divinyloxiranes, etc.), cyclic ketene acetals (e.g., 2-methylene-1,3-dioxolanes, polydioxolanes, 2-methylene-4-phenyl-1,3-dioxolane, 4,7-dimethyl-2-methylene-1,3-dioxolane, 5,6-benzo-2-methylene-1,3-dioxolane, etc.), and the like.

[0097] (Other oligomers) As oligomers other than the above-mentioned amine-modified photopolymerizable oligomers, polyurethane oligomers and / or polyurethane polyurea oligomers using polyester polyols obtained using plant-derived dicarboxylic acid components or diol components as raw materials may be used in consideration of environmental aspects.

[0098] As the vegetable oil-modified multifunctional polyester acrylate oligomer, any vegetable oil-modified polyester acrylate oligomer having 2 to 6 acrylate groups in the molecule can be used without limitation.

[0099] Among them, for example, the use of one or more selected from EBECRYL 450, 452, 820, 1622 or tall oil fatty acid-modified hexafunctional polyester acrylate (eg, AgiSyn 716) is preferred because the biomass content of the photocurable inkjet ink composition can be increased.

[0100] These oligomers can be used alone or in combination of two or more.

[0101] (polymer) The polymer of the curable resin having an ethylenically unsaturated bond is a component that increases the molecular weight like the above-mentioned monomer or oligomer. Since it has a large molecular weight before being irradiated with active energy rays such as ultraviolet rays, it is a component that helps to improve the viscoelasticity of the ink composition.

[0102] Such polymers can be used in a state of being dissolved or dispersed in a monomer of a low-viscosity liquid, for example. As polymers having ethylenically unsaturated bonds, polydiallyl phthalate, acrylic resins having unreacted unsaturated groups, acrylic acid-modified phenolic resins, etc. can be cited. Among them, polydiallyl phthalate can be preferably used because of its particularly excellent compatibility with the above-mentioned monomers or oligomers.

[0103] Furthermore, the polymer having an ethylenically unsaturated bond may not be contained. However, when contained, the content of the polymer having an ethylenically unsaturated bond is preferably 0 to 50.0% by mass, more preferably 0 to 30.0% by mass, and further preferably 0 to 20.0% by mass, based on the entire photopolymerizable component.

[0104] [pigment] The photocurable inkjet ink composition of the present invention contains a pigment. The pigment is a component added to impart coloring power or covering power to the ink composition, and examples thereof include coloring pigments, white pigments, and metal powders. Examples of such pigments include, without particular limitation, organic and / or inorganic pigments conventionally used in ink compositions, such as those described below.

[0105] The average particle size of the pigment is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 350 nm or less. When the average particle size of the pigment is 500 nm or less, the photocurable inkjet ink composition can exhibit higher curability.

[0106] Examples of the pigment include dye lake pigments, azo pigments, benzimidazolone pigments, phthalocyanine pigments, quinacridone pigments, anthraquinone pigments, dioxazines pigments, indigo pigments, thioindigo pigments, perylene pigments, perinone pigments, dione pyrrolopyrrole pigments, isoindolinone pigments, nitro pigments, nitroso pigments, flavonoid pigments, quinophthalone pigments, pyranthrone pigments, indanthrone pigments, and various inorganic pigments.

[0107] Examples of these pigments include yellow pigments such as disazo yellow (Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 1) and Hansa Yellow, magenta pigments such as Brilliant Carmine 6B, Lake Red C, Watching Red, and quinacridone, cyan pigments such as phthalocyanine blue, phthalocyanine green, and alkaline blue, colored pigments such as titanium oxide, red iron oxide, antimony red, cadmium yellow, cobalt blue, Prussian blue, ultramarine, black iron oxide, chromium oxide green, carbon black, and graphite (including achromatic coloring pigments such as white and black), and metal powders such as aluminum paste and bronze powder.

[0108] The content of the pigment may be exemplified as about 1 to 20% by mass relative to the total ink composition, depending on the target coloring degree, but is not particularly limited. In addition, when preparing a colored ink composition, a pigment or dye of another color may be used as a complementary color, or an ink composition of another color may be added.

[0109] The average particle size (D50) of the pigment contained in the photocurable inkjet ink composition is preferably 50 nm or more, more preferably 100 nm or more from the viewpoint of coloring power, and is preferably 500 nm or less, more preferably 350 nm or less from the viewpoint of dispersion stability.

[0110] (Pigment dispersants and pigment dispersion resins) When a pigment is used as a colorant in the photocurable inkjet ink composition of the present invention, a pigment dispersant and / or a pigment dispersing resin different from the above-mentioned E. surface conditioning agent may be formulated.

[0111] As the pigment dispersant, one or more selected from known nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants can be used.

[0112] As the surfactant, for example, one or more selected from silicone surfactants (for example, polyether-modified silicone oil, polyester-modified polydimethylsiloxane, polyester-modified methyl alkyl polysiloxane, etc.), fluorine-based surfactants, oxyalkylene ether-based surfactants, acetylene glycol-based surfactants, phosphorus-based surfactants, sulfonic acid-based surfactants, etc. can be used.

[0113] In addition, as the pigment dispersing resin, one or more selected from polymer dispersants (e.g., carbodiimide, polyester, polyamine, polyesteramine, polyurethane, fatty acid amine dispersants, polyacrylates, polycaprolactones, polysiloxanes, multi-chain polymer nonionic, polymer ionic dispersants, etc.) can be used.

[0114] When the photocurable inkjet ink composition of the present invention contains a pigment dispersant or a pigment dispersing resin, it preferably contains 1 to 200 parts by mass of the pigment dispersant or the pigment dispersing resin based on 100 parts by mass of the total amount of the pigments used.

[0115] (Other ingredients) The photocurable inkjet ink composition of the present invention may contain various additives such as surfactants, polymerization inhibitors, freshness-improving agents, ultraviolet absorbers, antioxidants, defoamers, mildew inhibitors, rust inhibitors, thickeners, humectants, and pH adjusters as other components. In addition, a non-curable resin may or may not be added. In addition, a solvent may or may not be contained.

[0116] (Solvent) The photocurable ink composition for inkjet of the present invention may be formulated with a solvent as needed. Examples of the aforementioned solvent include ester organic solvents, ether organic solvents, ether ester organic solvents, ketone organic solvents, aromatic hydrocarbon solvents, nitrogen-containing organic solvents, and the like. In addition, examples of the aforementioned solvent include substances having a boiling point of 150 to 220° C. at 1 atmosphere. From the perspective of the curability of the ink composition, environmental issues, and the like, the aforementioned solvent is preferably not used as much as possible, and the proportion of the aforementioned solvent in the ink composition is preferably 5% by mass or less, and more preferably 2% by mass or less.

[0117] In order to prevent polymerization of the photocurable inkjet ink composition during storage, a known polymerization inhibitor may be contained. As the polymerization inhibitor, phenol compounds such as butylated hydroxytoluene or tocopherol acetate, nitrosamine, benzotriazole, hindered amine, etc. are preferably exemplified, and butylated hydroxytoluene is more preferably exemplified. By adding such a polymerization inhibitor, the viscosity increase of the ink composition caused by the polymerization reaction during storage can be suppressed. As the content of the polymerization inhibitor in the ink composition, when the total photopolymerizable component is set to 100 parts by mass, about 0.1 to 1.0 parts by mass can be exemplified.

[0118] (UV absorber) The ultraviolet absorber is a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a hydroxyphenyltriazine ultraviolet absorber, a cyanoacrylate ultraviolet absorber, a nickel complex ultraviolet absorber, and the like.

[0119] (Antioxidant) The antioxidants include phenol antioxidants, amine antioxidants, sulfur antioxidants, phosphorus antioxidants and the like.

[0120] (Defoaming agent) The defoaming agent is a silicone defoaming agent, a Pluronic (registered trademark, プルロニック) type defoaming agent, or the like.

[0121] The viscosity of the photocurable inkjet ink composition of the present invention at 25°C is preferably 6.0 cps or more, more preferably 8.0 cps or more, and further preferably 10.0 cps or more, preferably 90.0 cps or less, more preferably 80.0 cps or less, and further preferably 75.0 cps or less. A viscosity modifier and the like may be formulated in the ink composition as required. In addition, the viscosity described in the specification of this application is the viscosity measured at 25°C and 10 rpm using an E-type viscometer (RE100L type viscometer, manufactured by Toki Sangyo Co., Ltd.).

[0122] Furthermore, the surface tension is preferably less than 32.0 mN / m.

[0123] <Method for preparing photocurable inkjet ink composition> Next, a method for producing the photocurable inkjet ink composition of the present invention using these materials will be described.

[0124] The photocurable inkjet ink composition of the present invention can be obtained by, for example, dispersing and mixing the components using a disperser such as a wet circulation mill, a bead mill, a ball mill, a sand mill, an attritor, a roller mill, a DCP mill, a stirrer, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a high-pressure homogenizer (Micro fluidizer, Nanomizer, Ultimizer, Genus PY, DeBEE2000, etc.), and a pearl mill, and adjusting the viscosity of the photocurable inkjet ink composition as needed. In addition, the photocurable inkjet ink composition can also be prepared by mixing a pigment, the above-mentioned pigment dispersant, and the above-mentioned photopolymerizable monomer to obtain a base ink composition in advance, and then adding the remaining parts of the above-mentioned components thereto in a manner to achieve the desired composition.

[0125] <Printing method> A printing method using the photocurable inkjet ink composition of the present invention will be described.

[0126] The inkjet printing device used is not particularly limited, and the following method can be cited: a photocurable inkjet ink composition is provided to a print head of an inkjet recording printing device, the ink composition is ejected from the print head onto a substrate to be printed, and then the ink composition landed on the substrate is exposed to active energy rays to cure it. Examples of active energy rays include ultraviolet rays, electron beams, and visible rays emitted from light-emitting diodes (LEDs) or various lamps or electrodes. In particular, the curing property is excellent for ultraviolet rays using light-emitting diodes (LEDs) as light sources.

[0127] In addition, the substrate is not particularly limited as long as it is a substrate applicable to a conventionally known photocurable inkjet ink composition. Examples of the substrate include plastics, paper, capsules, gel, metal foil, glass, wood, cloth, and the like. In addition, as for the aforementioned plastic, as its base material, for example, one or more selected from polyester polymers (for example, polyethylene terephthalate (PET), polyethylene naphthalate, etc.), cellulose polymers (for example, cellulose diacetate, cellulose triacetate (TAC), etc.), polycarbonate polymers, polyacrylic acid polymers (for example, polymethyl methacrylate, etc.), vinyl chloride polymers, polyolefin polymers (for example, polyethylene, polypropylene, polyolefin polymers having a cyclic or norbornene structure, ethylene-propylene copolymer polymers, etc.), polyamide polymers (for example, nylon, aromatic polyamide polymers, etc.), polystyrene polymers (for example, polystyrene, acrylonitrile-styrene copolymer polymers, etc.), polyimide polymers, polysulfone polymers, polyethersulfone polymers, polyetherketone polymers, polyphenylene sulfide polymers, polyvinyl alcohol polymers, polyvinylidene chloride polymers, polyvinyl butyral polymers, polyarylate polymers, polyoxymethylene polymers and polyepoxy polymers, mixtures of these polymers, etc. can be cited.

[0128] Specific examples of the method for printing and curing the ink composition of the present invention include a method in which the ink composition of the present invention is discharged onto a substrate using an inkjet head and then the coating film of the ink composition of the present invention landed on the substrate is exposed to light to cure the coating film.

[0129] For example, the ink composition of the present invention can be ejected onto a substrate (printing of an image) by providing the ink composition of the present invention to a low-viscosity corresponding print head of an inkjet recording printer, and ejecting the ink composition from the print head in such a manner that the coating film thickness reaches, for example, 1 to 60 μm relative to the substrate. In addition, light exposure and curing (curing of an image) can be performed by irradiating light to the coating film of the ink composition of the present invention applied to the substrate as an image.

[0130] As the inkjet recording printing apparatus for printing the ink composition of the present invention, a conventionally used inkjet recording printing apparatus can be used. In addition, when a continuous inkjet recording printing apparatus is used, a conductive agent is further added to the ink composition of the present invention to adjust the conductivity.

[0131] As the light source for curing the above-mentioned coating film, there can be cited ultraviolet rays (UV lamp), ultraviolet rays (metal halide lamp), ultraviolet rays (light emitting diode (LED)), electron beams, visible rays, etc. Ultraviolet rays using light emitting diode (LED) as a light source refer to "light irradiated from a light emitting diode that generates ultraviolet rays with a peak emission wavelength in the range of 360 to 420 nm".

[0132] Example The present invention is further described in detail by enumerating examples below, but the present invention is not limited to these examples. In addition, unless otherwise stated, "%" means "mass %" and "parts" means "mass parts". In addition, the numbers of the amounts of each material in the table are also "mass parts".

[0133] The photocurable inkjet ink compositions of the Examples and Comparative Examples described in Tables 2 to 5 below were prepared, and the test results of the photocurable inkjet ink compositions are described in Tables 2 to 5.

[0134] (Photocurable inkjet ink composition) The components used in the following Tables 2 to 5 are as follows.

[0135] PY150: Pigment Yellow 150 PR122: Pigment Red 122 PR254: Pigment Red 254 PB15:4: Pigment Blue 15:4 P.Bk.7: Carbon black S56000: polymer dispersant (Solsperse56000, manufactured by Japan LUBRIZOL Co., Ltd.) CN371NS: Amine-modified (meth)acrylate oligomer (an acrylated amine compound having two photopolymerizable functional groups and two amino groups in the molecule, Sartomer Arkema) DPGDA: Dipropylene glycol diacrylate (PO)NPGDA:PO (propoxylated) modified neopentyl glycol diacrylate A1 to A12: The polymer photopolymerization initiators containing ethylenically unsaturated bonds listed in Table 1 above TPO: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (number average molecular weight: 348) (acylphosphine oxide photopolymerization initiator) TX: (2-Carboxymethoxythioxanthone)-(polytetramethylene glycol 250) diester (number average molecular weight: 660) ((Omnipol TX) IGM Resins BV) DETX: 2,4-diethylthioxanthone (manufactured by IGM RESINS BV) UV22: Quinone inhibitor (BASF) BYK-377: Silicone surfactant (solid content 100%) (BYK) (Preparation of Photocurable Inkjet Ink Composition) The components were blended in the ratios (mass %) listed in Tables 2 to 5, and stirred and mixed to obtain photocurable inkjet ink compositions of Examples and Comparative Examples.

[0136] <Evaluation Method> (Viscosity) The photocurable inkjet ink compositions obtained in Examples and Comparative Examples were measured for viscosity (cps) using an E-type viscometer (trade name: RE100L viscometer, manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25° C. and a rotor speed of 10 rpm.

[0137] (Surface tension) The surface tension (mN / m) of each photocurable inkjet ink composition was measured at a temperature of 25° C. using a dynamic wettability tester (trade name: WET-6000, manufactured by RHESCA Corporation).

[0138] (LED curing) The photocurable inkjet ink compositions obtained in Examples and Comparative Examples were applied to the surface of a polyethylene terephthalate film (E5100 manufactured by Toyobo Co., Ltd.) using a bar coater No. 6 to obtain respective coated articles. Next, an LED lamp manufactured by Phoseon Technology Co., Ltd. was used at a cumulative light intensity of 80 mJ / cm 2 Under the irradiation conditions, the LED with a wavelength of 395nm was irradiated and evaluated according to the following evaluation criteria.

[0139] ○: The ink coating does not peel off even when wiped with a cotton swab.

[0140] ×: The ink coating peeled off when wiping with a cotton swab.

[0141] (Metal halide lamp curing) The photocurable inkjet ink compositions obtained in Examples and Comparative Examples were applied to the surface of a polyethylene terephthalate film (E5100 manufactured by Toyobo Co., Ltd.) using a bar coater No. 6 to obtain each coated article. Next, a conveyor-type light irradiation device (STM-250E-16 manufactured by Heraeus Co., Ltd., lamp: Z-8 lamp (metal halide type)) was used at 120 W × 50 m / min and UV cumulative light intensity of 75 mJ / cm 2 The irradiation was performed under the following irradiation conditions: [UV cumulative light intensity was obtained by measuring the irradiation intensity in the measurement ranges of 250-260nm, 280-320nm, 320-390nm, and 395-445nm using UVIMAP (UM 365H-S) manufactured by EIT Corporation as a measuring instrument]. Evaluation was performed according to the following evaluation criteria.

[0142] ○: The ink coating does not peel off even when wiped with a cotton swab.

[0143] ×: The ink coating peeled off when wiping with a cotton swab.

[0144] (Migration test from initiator) The photocurable inkjet ink compositions obtained in the examples and comparative examples were printed on the surface of a biaxially oriented polypropylene film (P2161 manufactured by Toyobo Co., Ltd.) using a single pass printer at a printing speed of 48 m / min, and then cured by irradiation with an LED at an irradiation energy of 500 mJ to obtain respective coatings. These coatings were cut into 13 mm×13 mm pieces to obtain test pieces.

[0145] Add 200 mL of 50% ethanol aqueous solution to the migration evaluation element (evaluation cell), and leave it at 40°C for 10 days with the back of the printed surface of the test piece in contact with the 50% ethanol aqueous solution. After 10 days, recover the ethanol aqueous solution, and add 0.2 mg of the internal standard solution (terphenyl) to the recovered 200 mL ethanol aqueous solution. After passing the ethanol aqueous solution with the internal standard solution through a solid phase extraction column, extract the retained components with 1 mL of methanol. This obtains a methanol solution in which the components eluted from the test piece into the ethanol aqueous solution are concentrated 200 times.

[0146] For each methanol solution, the peak area of ​​the internal standard solution (1000 ppb) and the peak area of ​​the migration component were compared by GC / MS analysis. The concentration of the migration component derived from the photopolymerization initiator component in the filtrate was calculated from the GC / MS results and evaluated according to the following evaluation criteria.

[0147] 〇:10ppb or less △: greater than 10ppb and less than 1ppm ×: greater than 1ppm [Table 2]

[0148] [Table 3]

[0149] [Table 4]

[0150] [Table 5]

[0151] According to various embodiments of the ink composition of the present invention, the ink composition of the present invention has not only suitable viscosity and surface tension, but also excellent LED curability and metal halide lamp curability, and no migration occurs.

[0152] In contrast, according to Comparative Example 1 containing a non-polymer initiator and a sensitizer, migration occurred. According to Comparative Examples 2 and 3 using only one of a polymer initiator and a polymer sensitizer, LED curability and metal halide lamp curability were poor, and migration from the initiator could not be evaluated. According to Comparative Example 4 not containing an amine-modified oligomer, LED curability and metal halide lamp curability were poor. In addition, according to Comparative Example 5 not containing a surface conditioner, the wetting and spreading of ink dots due to excessive surface tension was low.

[0153] According to Comparative Example 6, in which the total amount of the polymer initiator and the amine-modified oligomer in the ink composition exceeded 40%, the viscosity of the ink composition exceeded 100 cps, and it was difficult to use it as an inkjet ink. According to Comparative Example 7, in which the total amount was less than 5%, the LED curability and metal halide lamp curability were poor. In addition, according to Comparative Examples 8 and 9, in which the ratio of the polymer initiator / amine-modified oligomer was outside the range of 1 / 9 to 9 / 1, the LED curability and metal halide lamp curability were poor.

Claims

1. A photocurable inkjet ink composition, characterized in that: Contains the following A~E: A. A polymer photopolymerization initiator containing ethylenically unsaturated bonds; B. Thioxanthone polymer photosensitizer with molecular weight above 500; C. (Meth)acrylate polymerizable compounds; D. an amine-modified photopolymerizable oligomer having a weight average molecular weight of 500 to 3,000 and a viscosity of less than 4,000 cps; E. Surface conditioning agent, The ratio of A / D is 1 / 9 to 9 / 1, the total amount of A and D in the ink composition is 5 to 40%, the content of the photopolymerization initiator with a molecular weight of less than 500 is less than 0.2%, the viscosity is less than 100 cps, and the surface tension is less than 32.0 mN / m.

2. The photocurable inkjet ink composition according to claim 1, wherein: The content of the sensitizer with a molecular weight of less than 500 is less than 0.2%.

3. The photocurable inkjet ink composition according to claim 1 or 2, wherein: Contains a pigment with an average particle size of 500nm or less.

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