Ink composition, ink set, printed matter, inkjet recording apparatus, recording method, and method for manufacturing printed matter

Abstract

To provide an active energy ray-curable ink composition capable of forming a cured film of the ink composition having adhesion to various substrates.SOLUTION: The active energy ray-curable ink composition to be discharged by an inkjet method contains a polymerizable compound. The polymerizable compound contains a polymerizable compound represented by the following general formula (1) (where R1 represents hydrogen or a methyl group; R2 represents hydrogen or a C1-10 optionally branched alkyl group; and R3 represents hydrogen or a C1-10 optionally branched alkyl group).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an ink composition, an ink set, a printed matter, an inkjet recording apparatus, a recording method, and a method for manufacturing a printed matter.

Background Art

[0002] In recent years, there has been a trend towards small-lot, multi-variety production of printed matter, and as an alternative to the conventional offset printing method, an inkjet printing method, which is an on-demand printing method, has attracted attention. The inkjet printing method is simpler than the conventional offset printing method and has advantages such as economy and energy savings.

[0003] Among such inkjet printing methods, there is an active energy ray-curable ink composition that cures by ultraviolet rays, electron beams, or other active energy rays. Since the active energy ray-curable ink composition has quick-drying properties, it can prevent ink bleeding even when printing on substrates that do not absorb or hardly absorb ink, such as plastic, glass, and coated paper.

[0004] For example, Patent Document 1 describes an active energy ray-curable ink characterized by containing a polymerizable compound having a specific structure. Patent Document 1 describes that this active energy ray-curable ink has excellent adhesion performance to polycarbonate substrates and vinyl chloride substrates.

[0005] Further, Patent Document 2 describes an active energy ray-curable ink characterized by containing a polymerizable compound having a specific structure. Patent Document 2 describes that this active energy ray-curable ink can form an image excellent in adhesion over time and abrasion resistance over time to polyvinyl chloride building materials.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Now, an active energy ray-curable ink composition ejected by an inkjet method is required to form a cured film with high adhesion to various substrates such as a flexible polyvinyl chloride resin substrate and a hard acrylic resin substrate.

[0008] An object of the present invention is to provide an active energy ray-curable ink composition capable of forming a cured film having adhesion to various substrates.

Means for Solving the Problems

[0009] As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by an ink composition containing a specific polymerizable compound, and has completed the present invention. Specifically, the present invention provides the following.

[0010] (1) An active energy ray-curable ink composition ejected by an inkjet method, containing a polymerizable compound, wherein the polymerizable compound contains a polymerizable compound represented by the following general formula (1).

Chemical formula

[0011] (2) The ink composition according to (1), wherein the polymerizable compound represented by the general formula (1) is a liquid at 20 °C and 1 atm.

[0012] (3) The ink composition according to (2), wherein the polymerizable compound represented by the general formula (1) has a vapor pressure at 20 °C of 60 Pa or less.

[0013] (4) The ink composition according to (1) or (2), wherein the total number of carbon atoms contained in R1R2R3 in the general formula (1) is 3 or more.

[0014] (5) The ink composition according to (1) or (2), which contains a binder resin having a weight average molecular weight of 10,000 or more, and the content of the binder resin is 0.05% by mass or more and 25% by mass or less in the total amount of the ink composition.

[0015] (6) The ink composition according to (1) or (2), wherein the polymerizable compound contains a polyfunctional polymerizable compound, and the polyfunctional polymerizable compound having 4 or more functional groups is 25% by mass or less in the total amount of the ink composition.

[0016] (7) The ink composition according to (6), wherein the total content of the binder resin and the polyfunctional polymerizable compound having 4 or more functional groups is 30% by mass or less in the total amount of the ink composition.

[0017] (8) The ink composition according to (1) or (2), which contains a coloring material and may further contain a dispersant for dispersing the coloring material. When the dispersant is contained, the content of the dispersant is less than the content of the coloring material.

[0018] (9) The ink composition according to (1) or (2), which is cured by active energy rays irradiated from an LED lamp.

[0019] (10) An ink set containing the ink composition according to (1) or (2).

[0020] (11) A printed matter printed with the ink composition according to (1) or (2).

[0021] (12) An inkjet recording apparatus provided with a storage mechanism filled with the ink composition according to (1) or (2).

[0022] (13) A recording method of ejecting the ink composition according to (1) or (2) by an inkjet method.

[0023] (14) A method for manufacturing a printed matter by ejecting the ink composition according to (1) or (2) by an inkjet method Method for manufacturing a printed matter.

Effect of the Invention

[0024] The active energy ray-curable ink composition of the present invention can form a cured film of an ink composition having adhesion to various substrates.

Mode for Carrying Out the Invention

[0025] Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention.

[0026] ≪1. Active energy ray-curable ink composition≫ The active energy ray-curable ink composition according to the present embodiment contains a polymerizable compound, and is characterized by containing a polymerizable compound represented by the following general formula (1).

[0027]

Chemical formula

[0028] An active energy ray-curable ink composition that cures by active energy rays is required to form a cured film with good adhesion to various base materials such as a flexible film base material like a polyvinyl chloride resin or a hard acrylic resin. In particular, an acrylic resin base material is a relatively hard and transparent base material that is used in a wide range of applications, but there has been a problem that it is difficult to form a cured film of an ink composition having sufficient adhesion.

[0029] However, surprisingly, it has been clarified by the research of the present inventor that an active energy ray-curable ink composition according to this embodiment containing a predetermined amount of a polymerizable compound represented by such a general formula (1) can form a cured film with good adhesion to various base materials such as a hard acrylic resin.

[0030] Since the polymerizable compound represented by the general formula (1) has an amide group, intermolecular interactions such as hydrogen bonds act between the compounds, and the intermolecular distance tends to become close. As a result, the polymerization reaction of the polymerizable compound represented by the general formula (1) easily proceeds, and as a result, it becomes possible to form a cured film having adhesion to various base materials.

[0031] In addition, the active energy ray-curable ink composition according to this embodiment may contain a polymerization initiator as an optional component. However, when a polymerization initiator that is not listed as a candidate for inclusion as a substance of very high concern (SVHC) in Annex XIV of the REACH Regulation established by the European Union is used as this polymerization initiator, compared with the case where a polymerization initiator that is listed as a candidate for inclusion as a substance of very high concern is used, the curability of the active energy ray-curable ink composition may relatively decrease.

[0032] However, in the case of an active energy ray-curable ink composition containing a predetermined amount of the polymerizable compound represented by the general formula (1), even if a polymerization initiator that relatively easily reduces the curability of the ink composition is used, it is possible to suppress a decrease in the curability of the ink composition.

[0033] Note that the active energy ray-curable ink composition according to the present embodiment may be a colored ink containing a coloring material. In this specification, the "coloring material" includes dyes and pigments, and for example, dyes or pigments contained in colored inks that form images such as yellow, magenta, cyan, black, red, orange, violet, blue, green, and intermediate colors or light colors thereof, white dyes or white pigments contained in white ink, and bright coloring materials contained in metallic ink are also used as concepts included.

[0034] This colored ink may be a colored ink that forms images such as yellow, magenta, cyan, black, red, orange, violet, blue, green, and intermediate colors or light colors thereof. Further, the colored ink may be a white ink containing a white coloring material, or may be a metallic ink containing a bright coloring material or the like.

[0035] Further, when the active energy ray-curable ink composition according to the present embodiment contains a coloring material, it may contain a dispersant that disperses at least a part of the coloring material in the ink composition.

[0036] Further, the active energy ray-curable ink composition according to the present embodiment may be a clear ink that does not contain a coloring material. Specifically, it may be a primer ink for forming a primer layer on the surface of a substrate or the like, an overcoat ink for forming an overcoat layer on the surface of a recorded matter, a matting ink composition for matting the surface of a recorded matter (object), an ink composition for imparting gloss or texture, or an ink containing an ultraviolet absorber, a light stabilizer, or the like for forming a weather-resistant layer.

[0037] Incidentally, the water content in the active energy ray-curable ink composition according to the present embodiment is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 1.0% by mass or less in the total amount of the ink composition.

[0038] Hereinafter, each component contained in the active energy ray-curable ink composition according to the present embodiment will be described.

[0039] [Polymerizable compound] The active energy ray-curable ink composition according to the present embodiment contains a polymerizable compound. The polymerizable compound is a compound (polymerizable monomer) having one or more ethylenically unsaturated double bonds and polymerizing upon irradiation with active energy rays to form a cured product. The active energy rays include electromagnetic waves such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, visible light rays, infrared rays, X-rays, γ-rays, etc., as well as electron beams, proton beams, neutron beams, etc. This polymerizable compound is mainly liquid and has a function of polymerizing to form a cured product, and also has a function as a dispersion medium or solvent of the ink composition.

[0040] The polymerizable compound may be a monofunctional polymerizable compound having one ethylenically unsaturated double bond in the compound, or a polyfunctional polymerizable compound having two or more ethylenically unsaturated double bonds in the compound.

[0041] Also, the polymerizable compound may be a polymerizable compound having a relatively large weight average molecular weight such as those referred to as oligomers.

[0042] Now, the polymerizable compound contained in the active energy ray-curable ink composition according to the present embodiment contains a polymerizable compound represented by the following general formula (1).

[0043] [Chemical formula] (In the formula, R1 is hydrogen or a methyl group, R2 is hydrogen or an optionally branched alkyl group having 1 to 10 carbon atoms, and R3 is hydrogen or an optionally branched alkyl group having 1 to 10 carbon atoms, or an optionally branched alkyl group having 1 to 10 carbon atoms containing a functional group.)

[0044] Note that R1, R2, and R3 may be the same or different. R1 is more preferably hydrogen. R2 is preferably hydrogen or an optionally branched alkyl group having 1 to 6 carbon atoms, more preferably an optionally branched alkyl group having 2 to 4 carbon atoms, and even more preferably an optionally branched alkyl group having 2 to 3 carbon atoms. R3 is preferably an optionally branched alkyl group having 1 to 8 carbon atoms or an optionally branched alkyl group having 2 to 6 carbon atoms containing a functional group, more preferably an optionally branched alkyl group having 2 to 4 carbon atoms, and even more preferably an optionally branched alkyl group having 2 to 3 carbon atoms.

[0045] Examples of the "functional group" in the optionally branched alkyl group having 1 to 10 carbon atoms containing a functional group include, but are not limited to, a hydroxy group, an alkoxy group, a carboxy group, a carbonyl group, an amino group, an imino group, a cyano group, an azo group, an acyl group, an acetyl group, a sulfo group, a nitro group, and the like.

[0046] Examples of the polymerizable compound represented by the general formula (1) include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-ethyl-N-methyl-(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-dibutyl(meth)acrylamide, N-ethyl-N-butyl-acrylamide, N-isopropyl(meth)acrylamide, N-propyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-octyl(meth)acrylamide, N-2-ethylhexyl(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, N-[3-(dimethylamino)propyl](meth)acrylamide, diacetone(meth)acrylamide, N-tert-butyl(meth)acrylamide, N-(dibutylaminomethyl)(meth)acrylamide, and the like. The active energy ray-curable ink composition according to the present embodiment may contain one kind of the polymerizable compound represented by the general formula (1), or may contain a plurality of the polymerizable compounds represented by the general formula (1). Note that “(meth)acrylate” means both “acrylate” and “methacrylate”.

[0047] The content of the polymerizable compound represented by the general formula (1) is not particularly limited, but it is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, even more preferably 10% by mass or more, and even more preferably 15% by mass or more in the total amount of the ink composition. The content of the polymerizable compound represented by the general formula (1) is preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 75% by mass or less, even more preferably 70% by mass or less, and even more preferably 60% by mass or less in the total amount of the ink composition. The content of the polymerizable compound represented by the general formula (1) is preferably 2% by mass or more and 90% by mass or less, more preferably 5% by mass or more and 80% by mass or less, still more preferably 8% by mass or more and 75% by mass or less, even more preferably 10% by mass or more and 70% by mass or less, and even more preferably 15% by mass or more and 60% by mass or less in the total amount of the ink composition.

[0048] When the content of the polymerizable compound represented by the general formula (1) is within the above range, the solubility of polymer components such as resins and oligomers becomes good, and the polymer components can act as components for imparting or improving the coating film performance. Furthermore, when the content of the polymerizable compound represented by the general formula (1) is within the above range, the ink composition containing the components can be made into an ink composition that maintains a stable state.

[0049] In addition, when the content of the polymerizable compound represented by the general formula (1) is within the above-mentioned range, the solubility of the components contained in the ink composition such as the polymerization initiator, polymerization chain transfer agent, and additives becomes good, and furthermore, the curability is good, and it can be made excellent in ejection property and coating film performance. Compounds that are not candidates for inclusion in the list of substances of very high concern listed in Annex XIV of the REACH Regulation established by the European Union, which will be described later (for example, polymerization initiators corresponding to formulas (2) to (8) described later), may be difficult to dissolve in general polymerizable compounds, and in addition, since the curing performance as a polymerization initiator is insufficient, it may be necessary to increase the addition amount, and it may be a problem to maintain good solubility in the ink composition. When the content of the polymerizable compound represented by the general formula (1) is within the above-mentioned range, it becomes possible to maintain good solubility in the ink composition while maintaining the curing performance as a polymerization initiator.

[0050] The polymerizable compound represented by the general formula (1) is preferably a liquid at 20°C under 1 atm. The active energy ray-curable ink composition may be stored in a cool and dark place. In particular, when the ink composition is stored in a refrigerator, the components contained in the ink composition (such as polymerization initiators, polymerization chain transfer agents, antioxidants, ultraviolet absorbers, stabilizers, pH adjusters, polymerization inhibitors, surfactants, dispersants, dispersion aids, resins, oligomers, and other constituent components contained in the ink composition) may precipitate. Therefore, since the polymerizable compound represented by the general formula (1) is a liquid at 20°C under 1 atm, it is possible to suppress the volatilization of the polymerizable compound represented by the general formula (1) during storage, so that it is possible to suppress the precipitation of the components contained in the ink composition and improve the storage stability. In addition, due to good solubility, the fluidity of the ink composition inside the nozzle and the inkjet head becomes high, and it becomes possible to improve the inkjet ejection property. Furthermore, since the polymerizable compound represented by the general formula (1) is a liquid at 20°C under 1 atm, the curability can be improved, and it is possible to suppress the separation or precipitation of the solute from the cured coating film, so that a uniform coating film can be obtained and the physical properties of the coating film after curing of the ink composition can be made good.

[0051] The polymerizable compound represented by the general formula (1) that is a liquid at 1 atm and 20°C includes, for example, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-ethyl-N-methyl-(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-dibutyl(meth)acrylamide, N-ethyl-N-butyl-acrylamide, N-isopropyl(meth)acrylamide, N-propyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-octyl(meth)acrylamide, N-2-ethylhexyl(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, N-[3-(dimethylamino)propyl](meth)acrylamide, and the like.

[0052] The polymerizable compound represented by the general formula (1) preferably has a vapor pressure at 20°C of 60 Pa or less, more preferably 50 Pa or less. When the vapor pressure at 20°C is high (high volatility), the ink composition is likely to dry near the nozzle, components contained in the ink composition may precipitate near the nozzle, or the viscosity of the ink composition may become too high, which may deteriorate the inkjet ejectability. However, when the vapor pressure at 20°C is 60 Pa or less, more preferably 50 Pa or less, drying of the ink composition near the nozzle, precipitation of components contained in the ink composition, and increase in the viscosity of the ink composition can be suppressed, and the inkjet ejectability can be made good.

[0053] Examples of the polymerizable compound represented by the general formula (1) and having a vapor pressure of 60 Pa or less at 20°C include N,N - diethyl(meth)acrylamide, N - ethyl - N - methyl - (meth)acrylamide, N,N - dipropyl(meth)acrylamide, N,N - dibutyl(meth)acrylamide, N - ethyl - N - butyl - acrylamide, N - isopropyl(meth)acrylamide, N - propyl(meth)acrylamide, N - butyl(meth)acrylamide, N - hexyl(meth)acrylamide, N - octyl(meth)acrylamide, N - 2 - ethylhexyl(meth)acrylamide, N - (2 - hydroxyethyl)(meth)acrylamide, N - [3 - (dimethylamino)propyl](meth)acrylamide, and the like.

[0054] In the polymerizable compound represented by the general formula (1), the total number of carbon atoms contained in R1R2R3 is preferably 3 or more, more preferably 4 or more. As the upper limit of the total number of carbon atoms contained in R1R2R3 in the general formula (1), it is preferably 18 or less, more preferably 10 or less, and even more preferably 8 or less. By being within this range, the above - mentioned effects can be made better.

[0055] In the polymerizable compound represented by the general formula (1), it is more preferable that both R2 and R3 are alkyl groups. By making the acid - base interaction appropriate, the storage stability of the ink composition becomes good. Also, by maintaining good solubility of the components contained in the ink composition (such as polymerization initiators, polymerization chain transfer agents, antioxidants, ultraviolet absorbers, stabilizers, pH adjusters, polymerization inhibitors, surfactants, dispersants, dispersion aids, resins, oligomers, and other components included in the ink composition), the inkjet ejection property can be made good, and furthermore, a uniform coating film can be obtained.

[0056] In addition, the active - energy - ray - curable ink composition according to this embodiment may contain other polymerizable compounds different from the polymerizable compound represented by the general formula (1).

[0057] Examples of other monofunctional polymerizable compounds different from the polymerizable compound represented by the general formula (1) include tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl) (meth)acrylate, (2-methyl-2-isobutyl-1,3-dioxolan-4-yl) (meth)acrylate, (cyclohexane spiro-2-(1,3-dioxolan-4-yl)) (meth)acrylate, 4-t-butylcyclohexyl (meth)acrylate which is an alkylcycloalkyl acrylate, n-butylcyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, γ-butyrolactone (meth)acrylate, cresol (meth)acrylate, 2-acryloyloxyethyl phthalate, 2-acryloyloxyethyl-2-hydroxyethyl phthalate, 2-acryloyloxyethyl hexahydrophthalate, 2-acryloyloxypropyl phthalate, para-cumylphenoxyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, 1-adamantyl (meth)acrylate, cyclohexyl (meth)acrylate, cyclooctyl (meth)acrylate, hydroxycyclohexyl (meth)acrylate, 3-3-5-trimethylcyclohexyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth), N-vinylpyrrole acrylate, acryloylmorpholine, N-vinylcaprolactam, imide (meth)acrylate, isooctyl (meth)acrylate, tridecyl (meth)acrylate, lauryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, stearyl (meth)acrylate, isodecyl (meth)acrylate, caprolactone (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, 2-methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate,2-ethylhexyl (meth)acrylate, vinylcyclohexane, tert-butyl-4-ethynylcyclohexane, cycloheptyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclobutyl (meth)acrylate, phenyl (meth)acrylate, styrene, N-vinylpyrrolidone, N-vinyl oxazolidone, 2-vinyl-2-oxazoline N-vinylpyridine, N-vinylimidazole, 2-isopropenyl-2-oxazoline, methyl (meth)acrylate, butyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, octyl (meth)acrylate, trifluoroethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, methyl α-(hydroxymethyl)(meth)acrylate, ethyl α-(hydroxymethyl)(meth)acrylate, n-butyl α-(hydroxymethyl)(meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, N-vinyl succinimide, N-vinyl methylcarbamate, N,N-methylvinylacetamide, (meth)acryloyloxyethyltrimethylammonium chloride, (meth)acrylonitrile, and those having various modifications such as alkoxy modification and caprolactone modification of these acrylates can be mentioned. These other polymerizable compounds may be used alone or in combination of a plurality of polymerizable compounds. Note that "(meth)acrylate" means both "acrylate" and "methacrylate".

[0058] Examples of other polyfunctional polymerizable compounds different from the polymerizable compound represented by the general formula (1) include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, long-chain aliphatic di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, ethylene oxide modification (EO modification) (2) of 1,6-hexanediol di(meth)acrylate, ethylene oxide modification (EO modification) (3) of 1,6-hexanediol di(meth)acrylate, ethylene oxide modification (EO modification) (5) of 1,6-hexanediol di(meth)acrylate, propylene oxide modification (PO modification) (2) of 1,6-hexanediol di(meth)acrylate, propylene oxide modification (PO modification) (3) of 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide modification (EO modification) (2) of neopentyl glycol di(meth)acrylate, ethylene oxide modification (EO modification) (3) of neopentyl glycol di(meth)acrylate, propylene oxide modification (PO modification) (2) of neopentyl glycol di(meth)acrylate, propylene oxide modification (PO modification) (8) of neopentyl glycol di(meth)acrylate, propylene oxide modification (PO modification) (16) of neopentyl glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate hydroxy pivalate, caprolactone modification (2) of neopentyl glycol di(meth)acrylate hydroxy pivalate, caprolactone modification (4) of neopentyl glycol di(meth)acrylate hydroxy pivalate, polyalkylene glycol diacrylate, ethylene oxide modification (EO modification) (4) of polyalkylene glycol diacrylate, ethylene oxide modification (EO modification) (9) of polyalkylene glycol diacrylate,Ethylene oxide modification (EO modification) of polyalkylene glycol diacrylate (14), Ethylene oxide modification (EO modification) of polyalkylene glycol diacrylate (23), Ethylene oxide modification (EO modification) of polyalkylene glycol diacrylate (46), Propylene oxide modification (PO modification) of polyalkylene glycol diacrylate (3), Propylene oxide modification (PO modification) of polyalkylene glycol diacrylate (7), Propylene oxide modification (PO modification) of polyalkylene glycol diacrylate (12), Ethylene oxide and propylene oxide modification of polyalkylene glycol diacrylate (PO modification (12) & EO modification (6)), Ethylene oxide and propylene oxide modification of polyalkylene glycol diacrylate (PO modification (6) & EO modification (12)), Ethylene oxide and propylene oxide modification of polyalkylene glycol diacrylate (PO modification (4) & EO modification (12)), Ethylene oxide and propylene oxide modification of polyalkylene glycol diacrylate (PO modification (4) & EO modification (17)), Ethylene oxide and propylene oxide modification of polyalkylene glycol diacrylate (PO modification (13) & EO modification (5)), Butylene oxide modification (BO modification) of polyalkylene glycol diacrylate (3.5), Butylene oxide modification (BO modification) of polyalkylene glycol diacrylate (9), Butylene oxide modification (BO modification) of polyalkylene glycol diacrylate (14), Stearic acid-modified pentaerythritol di(meth)acrylate, Propylene glycol di(meth)acrylate, Glycerol di(meth)acrylate, Triethylene glycol di(meth)acrylate, 2-(2-Vinyloxyethoxy)ethyl acrylate, Tetraethylene glycol di(meth)acrylate, Tetramethylene glycol di(meth)acrylate, Butylene glycol di(meth)acrylate, Propoxylated neopentyl glycol di(meth)acrylate, Polyethylene glycol di(meth)acrylate, Polypropylene di(meth)acrylate, Triglycerol di(meth)acrylate,Neopentyl glycol modified trimethylolpropane di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, methoxylated cyclohexyl di(meth)acrylate, acrylated isocyanurate, bis(acryloxyneopentyl glycol) adipate, bisphenol A di(meth)acrylate, ethylene oxide modification (EO modification) (2) of bisphenol A di(meth)acrylate, ethylene oxide modification (EO modification) (3) of bisphenol A di(meth)acrylate, ethylene oxide modification (EO modification) (4) of bisphenol A di(meth)acrylate, ethylene oxide modification (EO modification) (10) of bisphenol A di(meth)acrylate, ethylene oxide modification (EO modification) (20) of bisphenol A di(meth)acrylate, ethylene oxide modification (EO modification) (30) of bisphenol A di(meth)acrylate, propylene oxide modification (PO modification) (3) of bisphenol A di(meth)acrylate, ethylene oxide and propylene oxide modification (PO modification (6) & EO modification (3)) of bisphenol A di(meth)acrylate, tetrabromobisphenol A di(meth)acrylate, bisphenol S di(meth)acrylate, butanediol di(meth)acrylate, phthalic acid di(meth)acrylate, phosphoric acid di(meth)acrylate, zinc di(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethylene oxide modification (EO modification) (4) of pentaerythritol tetra(meth)acrylate, ethylene oxide modification (EO modification) (35) of pentaerythritol tetra(meth)acrylate, propylene oxide modification (PO modification) (4) of pentaerythritol tetra(meth)acrylate, propylene oxide modification (PO modification) (10) of pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide modification (EO modification) (6) of dipentaerythritol hexa(meth)acrylate, ethylene oxide modification (EO modification) (12) of dipentaerythritol hexa(meth)acrylateEthylene oxide modification (EO modification) (18) of dipentaerythritol hexa(meth)acrylate, ethylene oxide modification (EO modification) (24) of dipentaerythritol hexa(meth)acrylate, ethylene oxide modification (EO modification) (48) of dipentaerythritol hexa(meth)acrylate, propylene oxide modification (PO modification) (6) of dipentaerythritol hexa(meth)acrylate, caprolactone modification (2) of dipentaerythritol hexa(meth)acrylate, caprolactone modification (3) of dipentaerythritol hexa(meth)acrylate, caprolactone modification (6) of dipentaerythritol hexa(meth)acrylate, caprolactone modification (12) of dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethylene oxide modification (EO modification) (3) of trimethylolpropane tri(meth)acrylate, ethylene oxide modification (EO modification) (6) of trimethylolpropane tri(meth)acrylate, ethylene oxide modification (EO modification) (9) of trimethylolpropane tri(meth)acrylate, ethylene oxide modification (EO modification) (15) of trimethylolpropane tri(meth)acrylate, ethylene oxide modification (EO modification) (20) of trimethylolpropane tri(meth)acrylate, ethylene oxide modification (EO modification) (30) of trimethylolpropane tri(meth)acrylate, propylene oxide modification (PO modification) (3) of trimethylolpropane tri(meth)acrylate, propylene oxide modification (PO modification) (6) of trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerin tri(meth)acrylate, ethylene oxide modification (EO modification) (3) of glycerin tri(meth)acrylate, ethylene oxide modification (EO modification) (6) of glycerin tri(meth)acrylate, ethylene oxide modification (EO modification) (9) of glycerin tri(meth)acrylate, ethylene oxide modification (EO modification) (20) of glycerin tri(meth)acrylate, propylene oxide modification (PO modification) (3) of glycerin tri(meth)acrylatePropion oxide modification (PO modification) of glycerol tri(meth)acrylate (5.5), propion oxide modification (PO modification) of glycerol tri(meth)acrylate (6), propion oxide modification (PO modification) of glycerol tri(meth)acrylate (9), dimethyloltricyclodecane diacrylate, and (meth)acrylates with different degrees of modification, different types of modification, and different structures, etc. can be mentioned.

[0059] The active energy ray-curable ink composition according to this embodiment preferably contains a monofunctional polymerizable compound and a polyfunctional polymerizable compound (polyfunctional monomer) having two or more functional groups as other polymerizable compounds different from the polymerizable compound represented by the general formula (1). When containing a monofunctional polymerizable compound and a polyfunctional polymerizable compound, the content of the polyfunctional polymerizable compound is preferably 50% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less in the total amount of the ink composition.

[0060] Furthermore, when containing a polyfunctional polymerizable compound (polyfunctional monomer) having four or more functional groups, its content is preferably 25% by mass or less, more preferably 18% by mass or less, even more preferably 15% by mass or less, and still more preferably 10% by mass or less in the total amount of the ink composition. If the content of the polyfunctional polymerizable compound (polyfunctional monomer) having four or more functional groups is too high, curing shrinkage may occur where the volume shrinks due to curing. When curing shrinkage occurs, the ink coating film (cured film) may be relatively easily peeled off from the substrate, wrinkles or unevenness may occur on the surface of the ink coating film, and cracks or warping of the coating film may be relatively likely to occur. By the content of the polyfunctional polymerizable compound (polyfunctional monomer) having four or more functional groups being within the above range, the printing quality can be made good, and the peeling of the cured film due to curing shrinkage can be more effectively suppressed. As a result, it becomes possible to form a cured film having higher adhesion to the substrate.

[0061] In addition, when containing a binder resin having a weight average molecular weight of 10,000 or more described later, the total content of the binder resin and the polyfunctional polymerizable compound having four or more functional groups is preferably 30% by mass or less in the total amount of the ink composition, more preferably 27% by mass or less in the total amount of the ink composition, and even more preferably 25% by mass or less in the total amount of the ink composition. By containing a polyfunctional polymerizable compound having high reactivity and improving the crosslink density and a polymer resin component for improving printing quality and coating film resistance in the ink composition, the balance of curability, printing quality, and coating film physical properties can be made good, and inkjet ejectability can also be made good. When the contents of the binder resin and the polyfunctional polymerizable compound having four or more functional groups are within the above ranges, the effect is further improved.

[0062] In addition, as other polymerizable compounds different from the polymerizable compound represented by the general formula (1), it is preferable to contain a polymerizable oligomer. Generally, a polymerizable oligomer means a polymer in which a relatively small number of monomers are bonded. Examples of the polymerizable oligomer include compounds having a weight average molecular weight of less than 10,000 in which several to several tens of constitutional unit molecules are polymerized. By containing a predetermined amount of the polymerizable oligomer, it becomes possible to adjust the curability and viscosity of the ink composition. Furthermore, the polymerizable compound represented by the general formula (1) has high solubility in the polymerizable oligomer, and in the case of the active energy ray-curable ink composition according to the present embodiment containing the polymerizable compound represented by the general formula (1), it is possible to dissolve the polymerizable oligomer, and furthermore, it is possible to increase the solubility in other additives, and it becomes possible to widen the ink design range as desired by the designer.

[0063] Examples of the polymerizable oligomer include various ones such as urethane acrylate, epoxy acrylate, polyester acrylate, and polymer type acrylate (acrylic acrylate), and they can be obtained from Rahn AG, Sartomer, Daicel Corporation, Daisheng Fine Co., Ltd., Mitsubishi Chemical Corporation, Daiichi Kogyo Seiyaku Co., Ltd., Kyoeisha Chemical Co., Ltd., Shin-Nakamura Chemical Co., Ltd., etc.

[0064] When containing a polymerizable oligomer, the content of the polymerizable oligomer is preferably 1.0% by mass or more, more preferably 1.3% by mass or more, and still more preferably 1.5% by mass or more in the total amount of the ink composition. The content of the polymerizable oligomer is preferably 20.0% by mass or less, more preferably 17.0% by mass or less, and still more preferably 15.0% by mass or less in the total amount of the ink composition. The content of the polymerizable oligomer is preferably 1.0% by mass or more and 20.0% by mass or less, more preferably 1.3% by mass or more and 17.0% by mass or less, and still more preferably 1.5% by mass or more and 15.0% by mass or less in the total amount of the ink composition.

[0065] These polymerizable compounds may be solid or liquid at normal temperature. Among them, at least one of the polymerizable compounds contained in the ink composition according to this embodiment is preferably liquid at normal temperature. Since the polymerizable compound is liquid at normal temperature, this liquid polymerizable compound can be used as a solvent (dispersion medium) for dissolving or dispersing each component contained in the ink composition.

[0066] The content of the polymerizable compound is not particularly limited, but it is preferably 40% by mass or more, more preferably 50% by mass or more, and still more preferably 60% by mass or more in the total amount of the ink composition. When the content of the polymerizable compound is 40% by mass or more in the total amount of the ink composition, the curability of the cured film of the fluorescent layer formed when irradiated with active energy rays can be improved. The content of the polymerizable compound is preferably 90% by mass or less, more preferably 87% by mass or less, and still more preferably 85% by mass or less in the total amount of the ink composition. When the content of the polymerizable compound is 90% by mass or less in the total amount of the ink composition, the content of coloring materials and the like can be relatively increased, so that desired properties can be imparted to the ink composition and the resulting printed matter. The content of the polymerizable compound is preferably 40% by mass or more and 90% by mass or less, more preferably 50% by mass or more and 87% by mass or less, and still more preferably 60% by mass or more and 85% by mass or less in the total amount of the ink composition.

[0067] [Polymerization initiator] The active energy ray-curable ink composition according to the present embodiment may contain a polymerization initiator as needed. A polymerization initiator is a substance that promotes the polymerization reaction of the polymerizable compound in the ink composition by irradiation with active energy rays. In the ink composition according to the present embodiment, the polymerization initiator is not necessarily essential. For example, when an electron beam is used as the active energy ray, the polymerization initiator may not be used.

[0068] Specific examples of the polymerization initiator include, for example, bisacylphosphine oxides such as bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; acylphosphine oxide-based polymerization initiators such as 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, methyl 2,4,6-trimethylbenzoylphenylphosphinate, 2-methylbenzoyldiphenylphosphine oxide, isopropyl pivaloylphenylphosphinate, diphenyl-2,4,6-trimethylbenzoylphosphine = oxide, and aminoacetophenone-based polymerization initiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one, and thioxanthone-based polymerization initiators such as 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.

[0069] Among these, diphenyl-2,4,6-trimethylbenzoylphosphine oxide, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, and 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one can more effectively promote the polymerization reaction of polymerizable compounds, but they are candidates for inclusion as substances of very high concern listed in Annex XIV of the REACH Regulation established by the European Union. For this reason, it is preferable to contain a polymerization initiator other than these polymerization initiators. Moreover, in the case of the active energy ray-curable ink composition according to this embodiment containing a predetermined amount of the polymerizable compound represented by the general formula (1), even if it contains a polymerization initiator other than these polymerization initiators, it is possible to suppress a decrease in the curability of the ink composition.

[0070] Examples of polymerization initiators that are not candidates for inclusion as substances of very high concern listed in Annex XIV of the REACH Regulation established by the European Union include polymerization initiators containing a phosphine oxide derivative having two or more alkylbenzene structures in the molecule, polymerization initiators containing an alkoxyphosphine oxide derivative, and fluorenylaminoketone polymerization initiators. For example, Omnirad 819 (manufactured by IGM Resins B.V.), A-TPO-N (manufactured by Deroide Materials), SpeedCure TPO-L (manufactured by Sartomer), SpeedCure XKm (manufactured by Sartomer), NPI-20400 (manufactured by TRONLY), SPEEDCURE BMS (manufactured by Sartomer), mnirad ITX (manufactured by IGM Resins), etc. can be mentioned.

[0071] As the polymerization initiator that is not a candidate for inclusion as a substance of very high concern, for example, those having the following structures can be preferably used.

[0072]

Chemical formula

[0073]

Chem.

[0074]

Chem.

[0075]

Chem.

[0076]

Chem.

[0077]

Chem.

[0078]

Chem.

[0079] When the active energy ray-curable ink composition according to this embodiment contains a polymerization initiator, the content of the polymerization initiator is not particularly limited, but it is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2.0% by mass or more in the total amount of the ink composition. The content of the polymerization initiator is preferably 15.0% by mass or less, more preferably 12.0% by mass or less, and even more preferably 10.0% by mass or less in the total amount of the ink composition. The content of the polymerization initiator is preferably 1.0% by mass or more and 15.0% by mass or less, more preferably 1.5% by mass or more and 12.0% by mass or less, and even more preferably 2.0% by mass or more and 10.0% by mass or less in the total amount of the ink composition.

[0080] [Polymerization inhibitor] The ink composition according to this embodiment may contain a polymerization inhibitor as needed. The polymerization inhibitor is not particularly limited, and for example, diphenylpicrylhydrazide, tri-p-nitrophenylmethyl, p-benzoquinone, p-tert-butylcatechol, picric acid, copper chloride, methylhydroquinone, methoquinone, tert-butylhydroquinone, phenothiazines, nitrosoamines and other polymerization inhibitors can be used.

[0081] [Colorant] The active energy ray-curable ink composition according to this embodiment may contain a colorant as needed. When the active energy ray-curable ink composition according to this embodiment contains a colorant, the colorant is not particularly limited, and it may be a dye-based or a pigment-based, but it is preferable to use a pigment (pigment-based colorant) from the viewpoint of good resistance such as water resistance and light resistance of the recording. In the active energy ray-curable ink composition according to this embodiment, the pigments that can be used are not particularly limited, and examples include organic pigments or inorganic pigments used in conventional ink compositions. These may be used alone or in combination of two or more. Note that the ink composition according to this embodiment may not contain a colorant. Also, a pigment or a dye may be included in the resin and used.

[0082] When using a pigment in the active energy ray curable ink composition according to the present embodiment, the dispersion stability of the pigment can be improved by using a dispersant, a dispersion aid (pigment derivative), and a surfactant, which will be described later.

[0083] Specific organic pigments include, for example, insoluble azo pigments, soluble azo pigments, derivatives from dyes, phthalocyanine-based organic pigments, quinacridone-based organic pigments, perylene-based organic pigments, perinone-based organic pigments, azomethine-based organic pigments, anthraquinone-based organic pigments (anthrone-based organic pigments), xanthene-based organic pigments, diketopyrrolopyrrole-based organic pigments, dioxazine-based organic pigments, nickel azo-based pigments, isoindolinone-based organic pigments, pyranthrone-based organic pigments, thioindigo-based organic pigments, condensed azo-based organic pigments, benzimidazolone-based organic pigments, quinophthalone-based organic pigments, isoindoline-based organic pigments, quinacridone-based solid solution pigments, perylene-based solid solution pigments, and other pigments such as lake pigments and carbon black.

[0084] Examples of organic pigments are illustrated by Color Index (C.I.) numbers, including C.I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 20, 24, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 117, 120, 125, 128, 129, 130, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185, 213, 214, C.I. Pigment Red 5, 7, 9, 12, 48, 49, 52, 53, 57:1, 97, 112, 122, 123, 146, 149, 150, 168, 177, 180, 184, 192, 202, 206, 208, 209, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 255, 269, 291, C.I. Pigment Orange 16, 36, 43, 51, 55, 59, 61, 64, 71, 73, C.I. Pigment Violet 19, 23, 29, 30, 37, 40, 50, C.I. Pigment Blue 15, 15:1, 15:3, 15:4, 15:6, 16, 22, 60, 64, C.I. Pigment Green 7, 36, 58, 59, 62, 63, C.I. Pigment Brown 23, 25, 26, C.I. Pigment Black 7, etc.

[0085] In the active energy ray-curable ink composition according to this embodiment, specific examples of dyes that can be used include azo dyes, benzoquinone dyes, naphthoquinone dyes, anthraquinone dyes, cyanine dyes, squarylium dyes, croconium dyes, merocyanine dyes, stilbene dyes, diarylmethane dyes, triarylmethane dyes, fluoran dyes, spiropyran dyes, phthalocyanine dyes, indigo dyes such as indigoid, fulgide dyes, nickel complex dyes, and azulene dyes.

[0086] In the active energy ray-curable ink composition according to this embodiment, specific examples of inorganic pigments that can be used include titanium oxide, barium sulfate, calcium carbonate, zinc oxide, barium carbonate, silica, talc, clay, synthetic mica, alumina, zinc white, lead sulfate, yellow lead, zinc yellow, red iron oxide (III), ultramarine, dark blue, chromium oxide green, cobalt green, amber, titanium black, aluminum, titanium, indium, nickel, chromium, gold, silver, copper, synthetic iron black, iron oxide, mica, fish scale foil, bismuth oxychloride, inorganic solid solution pigments, and the like. In addition to the above pigments, materials having optical properties and functions other than for decorative purposes, such as conductive pigments, insulating pigments, pigments that absorb specific wavelengths, and pigments that emit or reflect specific wavelengths, can also be mentioned.

[0087] In the active energy ray-curable ink composition according to this embodiment, the average particle diameter of the pigments that can be contained may be any as long as the desired color development is possible, and is not particularly limited. Although it varies depending on the type of pigment used, from the viewpoint of good dispersibility and dispersion stability of the pigment and obtaining sufficient coloring power, the average particle diameter is preferably in the range of 5 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more. By the average particle diameter being equal to or greater than the above lower limit value, the light resistance of the ink composition can be improved. From the viewpoints of dispersion stability in the ink composition and inkjet ejection properties, the average particle diameter is preferably in the range of 1000 nm or less, more preferably 800 nm or less, even more preferably 500 nm or less, and still more preferably 350 nm. The average particle diameter of the pigment is preferably in the range of 5 nm or more and 1000 nm or less, more preferably 20 nm or more and 800 nm or less, and even more preferably 30 nm or more and 500 nm or less.

[0088] In the present embodiment, the volume average particle diameter of the pigment is the volume-based cumulative 50% particle diameter (D50) measured under the condition of 25°C using a particle size distribution measuring device (such as the particle size analyzer NANOTRAC WAVE manufactured by Microtrac Bell Corporation, "FPIA-3000S" manufactured by Sysmex Corporation, "FPAR-1000" manufactured by Otsuka Electronics Co., Ltd., etc.). In this specification, the "volume-based cumulative 50% particle diameter (D50)" means the particle diameter at which the cumulative volume calculated from the smaller diameter side is 50%. The "volume-based cumulative 50% particle diameter (D50)" may also be referred to as the "volume average particle diameter", "average particle diameter", or "median diameter".

[0089] In the active energy ray-curable ink composition according to the present embodiment, the content of the pigment is not particularly limited as long as a desired image can be formed and is appropriately adjusted. Specifically, although it varies depending on the type of pigment, it is preferably in the range of 0.05% by mass or more, more preferably in the range of 0.08% by mass or more, and even more preferably in the range of 0.1% by mass or more with respect to the total amount of the ink composition. It is preferably in the range of 20% by mass or less, more preferably in the range of 15% by mass or less, and even more preferably in the range of 10% by mass or less with respect to the total amount of the ink composition. The content of the pigment is preferably in the range of 0.05% by mass or more and 20% by mass or less, more preferably in the range of 0.08% by mass or more and 15% by mass or less, and even more preferably in the range of 0.1% by mass or more and 10% by mass or less with respect to the total amount of the ink composition. When the content of the pigment is in the range of 0.05% by mass or more or 20% by mass or less, it is possible to obtain an excellent balance between the dispersion stability and coloring power of the pigment.

[0090] In addition, the color for recording (printing) the active energy ray-curable ink composition according to the present embodiment is not particularly limited, and it may be selected and used in combination according to the purpose. The colors include inks of various colors such as yellow, magenta, cyan, black, red, orange, violet, blue, green, etc., and can also be used for light magenta, light cyan, light black, white, clear, fluorescent ink, etc. At this time, in an ink set including the active energy ray-curable ink composition according to the present embodiment, color materials of the same type of color may be selected.

[0091] [Dispersant] In the active energy ray-curable ink composition according to the present embodiment, a dispersant may be used as needed. As the dispersant, any dispersant used in the ink composition can be used. It is preferable to use a polymer dispersant as the dispersant. Such dispersants have a main chain composed of polyester-based, polyacrylic-based, polyurethane-based, polyamine-based, polycaprolactone-based, etc., and have polar groups such as amino groups, carboxyl groups, sulfone groups, and hydroxyl groups as side chains. In the case of polyacrylic-based dispersants, for example, Disperbyk-2000, 2001, 2008, 2009, 2010, 2020, 2020N, 2022, 2025, 2050, 2070, 2095, 2150, 2151, 2155, 2163, 2164, BYKJET-9130, 9131, 9132, 9133, 9151, 9152 (manufactured by BYK), Efka PX4310, PX4320, PX4330, PA4401, 4402, PA4403, 4570, 7411, 7477, PX4700, PX4701, PX4703 (manufactured by BASF), TREPLUS D-1200, D-1410, D-1420, MD-1000 (manufactured by Otsuka Chemical Co., Ltd.), Floren DOPA-15BHFS, 17HF, 22, G-700, 900, NC-500, GW-1500 (manufactured by Kyoeisha Chemical Co., Ltd.), etc. are used. In the case of polycaprolactone-based dispersants, for example, Ajisper PB821, PB822, PB881 (manufactured by Ajinomoto Fine-Techno Co., Inc.), Hinact KF-1000, T-6000, T-7000, T-8000, T-8000E, T-9050 (manufactured by Kawaken Fine Chemicals Co., Ltd.), Solsperse 20000, 24000, 32000, 32500, 32550, 32600, 33000, 33500, 34000, 35200, 36000, 37500, 39000, 71000, 76400, 76500, 86000, 88000, J180, J200 (manufactured by Lubrizol), TEGO Dispers 652, 655, 685, 688, 690 (manufactured by Evonik), etc. are used.Preferred dispersants include PB881, BYKJET-9130, 9131, 9132, 9133, 9151, 9152, Efka PX4310, PX4320, PX4330, PX4700, PX4701, PX4703, Solsperse 20000, 24000, 32000, 33000, 33500, 34000, 35200, 39000, 71000, 76500, 86000, 88000, J180, J200, TEGO Dispers 655, 685, 688, 690, etc. These can be used alone or as a mixture thereof.

[0092] The content of the dispersant is not particularly limited, but it is preferably adjusted according to the content of the coloring material contained in the ink composition. In particular, in the active energy ray-curable ink composition according to this embodiment containing the polymerizable compound represented by the general formula (1), it is preferable to adjust the content of the dispersant so that the content of the coloring material is more than the content of the dispersant (that is, the content of the dispersant is less than the content of the coloring material). Thereby, it becomes possible to effectively disperse the dispersibility of the coloring material in the ink composition, and the storage stability and ejection stability of the ink composition can be improved.

[0093] The lower limit value of the content of the dispersant is not particularly limited. It is added as necessary depending on R1, R2, R3 of the compound (1), the content of the compound (1), and other constituent components. When R2 and R3 have 2 to 4 carbon atoms, the dispersibility may be particularly good, and the dispersant can be reduced.

[0094] When the coloring material is an organic coloring material, the upper limit value of the content of the dispersant is preferably 80 parts by mass or less, more preferably 75 parts by mass or less, still more preferably 50 parts by mass or less, and even more preferably 35 parts by mass or less with respect to 100 parts by mass of the coloring material.

[0095] When the coloring material is an inorganic coloring material, the upper limit of the content of the dispersant is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less with respect to 100 parts by mass of the coloring material.

[0096] [Dispersion aid] In the active energy ray curable ink composition according to the present embodiment, a dispersion aid may be contained as necessary. The dispersion aid adsorbs on the surface of the coloring material (pigment), and the functional group enhances the affinity with the polymerizable compound and the dispersant in the ink composition, improving the dispersion stability. As the dispersion aid, known pigment derivatives having functional groups such as acidic groups, basic groups, and neutral groups on the organic pigment residue can be used.

[0097] [Surfactant] The ink composition according to this embodiment may contain a surfactant as needed. The surfactant is not particularly limited, but specific examples include "BYK-306", "BYK-307", "BYK-331", "BYK-333", "BYK-354", "BYK-361N", "BYK-371", "BYK-377", "BYK-378", "BYK-3455", "BYK-UV3500", "BYK-UV3505", "BYK-UV3510", "BYK-UV3535", "BYK-UV3570" manufactured by BYK and having dimethylpolysiloxane; "TEGO Flow425", "TEGO Glide100", "TEGO Glide110", "TEGO Glide130", "TEGO Glide432", "TEGO Glide435", "TEGO Glide440", "TEGO Glide450", "TEGO GlideZG400", "TEGO Twin4000", "TEGO Twin4200", "TEGO Wet270", "TEGO Rad2010", "TEGO Rad2010", "TEGO Rad2100", "TEGO Rad2200N", "TEGO Rad2250", "TEGO Rad2300", "TEGO Rad2500", "TEGO Rad2700" manufactured by Evonik; "Polyflow KL-401", "Polyflow KL-402", "Polyflow KL-403", "Polyflow KL-404" manufactured by Kyoeisha Chemical Co., Ltd.; in the case of acrylic polymers, "Polyflow No.75", "Polyflow No.77", "Polyflow No.90", "Polyflow No.95", "Polyflow No.99C" manufactured by Kyoeisha Chemical Co., Ltd.; "TEGO Wet500" manufactured by Evonik Degussa Japan Co., Ltd., and the like.

[0098] The content of the surfactant is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more in the total amount of the ink composition. Also, the content of the surfactant is preferably 5.0% by mass or less, more preferably 4.5% by mass or less, and even more preferably 4.0% by mass or less in the total amount of the ink composition. By setting it to 0.1% by mass or more or 5.0% by mass or less, the ink composition will have preferable wettability to a thermoplastic resin substrate or the like, and when recording (forming an image) on the substrate, the active energy ray-curable ink composition can spread wet without causing repellency, so that a particularly preferable ink composition can be obtained. The content of the surfactant is preferably 0.1% by mass or more and 5.0% by mass or less, more preferably 0.2% by mass or more and 4.5% by mass or less, and even more preferably 0.3% by mass or more and 4.0% by mass or less in the total amount of the ink composition.

[0099] [Binder resin] In the active energy ray-curable ink composition according to the present embodiment, a binder resin may be contained as necessary. The binder resin referred to here means a non-polymerizable resin, which is different from additives such as polymerizable resins, polymerizable oligomers, surfactants, and dispersants for dispersing color materials. The resin is not particularly limited. For example, acrylic resins, polystyrene resins, polyester resins, polyethylene terephthalate resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, polyethylene resins, polyurethane resins, rosin-modified resins, phenolic resins, xylene resins, terpene resins, polyamide resins, vinyl toluene-α-methylstyrene copolymers, ethylene-vinyl acetate copolymers, cellulose resins, silicone resins, acrylamide resins, epoxy resins, diallyl phthalate resins, allyl resins, or copolymer resins or mixtures thereof can be used. Among these, those containing at least one of vinyl chloride-vinyl acetate copolymer resin, polyethylene terephthalate resin, diallyl phthalate resin, acrylic resin, allyl resin, xylene resin, and cellulose resin are preferred. The binder resin is more preferably those containing at least one selected from the group consisting of vinyl chloride-vinyl acetate copolymer resin, diallyl phthalate resin, xylene resin, and acrylic resin. The weight average molecular weight of the binder resin is preferably 10,000 or more, and more preferably 15,000 or more. The weight average molecular weight of the binder resin is preferably 500,000 or less, and more preferably 300,000 or less. By the weight average molecular weight of the binder resin being within this range, the storage stability, ejection property, and coating film physical properties of the ink composition can be made good.

[0100] By containing a binder resin together with a polymerizable compound, it becomes possible to cure the ink composition in a state where the density inside the coating film is increased, and it becomes possible to improve the abrasion resistance and chemical resistance of the formed coating film. On the other hand, when a binder resin is contained together with the polymerizable compound, a part of the contained components such as the binder resin may precipitate during storage of the ink composition, and the storage stability and ejection stability may relatively decrease, and further, the formed coating film may become non-uniform or the color development may further decrease. Here, since the polymerizable compound represented by the general formula (1) has high solubility in the contained components, a decrease in storage stability and ejection stability hardly occurs. From this, by using an ink composition containing a binder resin together with the polymerizable compound represented by the general formula (1), it is possible to avoid the disadvantages caused by containing the binder resin and enjoy only the benefits of improving the abrasion resistance and chemical resistance of the formed coating film. Furthermore, the polymerizable compound represented by the general formula (1) has a low viscosity, and even when it contains specific components such as a binder resin, the viscosity of the ink composition does not become too high, and it is possible to suppress a decrease in storage stability and ejection stability.

[0101] When the active energy ray-curable ink composition according to the present embodiment contains a binder resin, the content of the binder resin is not particularly limited, but it is preferably 0.05% by mass or more, more preferably 0.08% by mass or more, further preferably 0.1% by mass or more, and still more preferably 0.3% by mass or more based on the total amount of the ink composition. The content of the binder resin is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, further preferably 10.0% by mass or less, and still more preferably 5.0% by mass or less in the total amount of the ink composition. The content of the binder resin is preferably 0.05% by mass or more and 20.0% by mass or less, more preferably 0.08% by mass or more and 15.0% by mass or less, and further preferably 0.1% by mass or more and 10.0% by mass or less in the total amount of the ink composition.

[0102] [Other Additives] The ink composition according to this embodiment may contain various additives as other additives, such as organic solvents, plasticizers, light stabilizers, waxes, ultraviolet absorbers, antioxidants, alignment agents, antibacterial agents, antiviral agents, and the like.

[0103] Also, the ink composition according to this embodiment may contain a volatile organic solvent. However, when the polymerizable compound contained is a liquid at room temperature, the polymerizable compound serves as a solvent (dispersion medium) for dissolving or dispersing each component, so it may not be necessary to contain a volatile organic solvent. Among these, when the polymerizable compound contained includes a liquid at room temperature, the content of the volatile organic solvent is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, still more preferably 5.0% by mass or less, and even more preferably 1.0% by mass or less in the total amount of the ink composition. When the polymerizable compound includes a liquid at room temperature and the content of the volatile organic solvent is 20.0% by mass or less in the total amount of the ink composition, it is possible to suppress the precipitation of the contained components due to the evaporation of the ink composition in the inkjet nozzle, so that it is possible to further improve the ejection performance of the inkjet.

[0104] (Viscosity and surface tension of the ink composition) From the viewpoints of inkjet ejection performance and ejection stability, the viscosity of the ink composition according to this embodiment is preferably 30 mPa·s or less, more preferably 25 mPa·s or less, and still more preferably 22 mPa·s or less at the ejection temperature (for example, 40°C). Also, the viscosity of the ink composition according to this embodiment at the ejection temperature (for example, 40°C) is preferably 3 mPa·s or more, more preferably 5 mPa·s or more, and still more preferably 8 mPa·s or more, but it is preferably adjusted appropriately according to the inkjet head used. The viscosity can be measured with a vibrating viscometer, a rheometer, a falling ball viscometer, or the like.

[0105] Furthermore, from the viewpoints of inkjet ejection property, ejection stability, and leveling property on a substrate, the surface tension of the ink composition according to the present embodiment preferably has a surface tension of 20 mN / m or more at 25°C, more preferably 23 mN / m or more, and even more preferably 25 mN / m or more. Also, the surface tension of the ink composition according to the present embodiment is preferably 40 mN / m or less, more preferably 37 mN / m or less, and even more preferably 35 mN / m or less.

[0106] (Method for manufacturing ink composition) The method for manufacturing the active energy ray-curable ink composition according to an embodiment of the present invention is not particularly limited, and a conventionally known method can be used. For example, using a disperser, a polymerizable compound, a colorant, and, if necessary, a dispersant are mixed and dispersed, and then a polymerization initiator, a polymerization inhibitor, a leveling agent, etc. are added as necessary and stirred uniformly to obtain a mixture, and then the ink composition is obtained by filtering with a filter.

[0107] ≪2. Ink set≫ The above active energy ray-curable ink composition may be a colored ink, a clear ink containing no colorant, a primer ink, or an overcoat ink. The ink set according to the present embodiment may be an ink set combining these ink compositions.

[0108] The ink set according to this embodiment may be an ink set in which at least one ink composition included in the ink set is an ink composition containing a polymerizable compound represented by the above general formula (1). For example, in an ink set including an ink composition A and an ink composition B, the ink composition A may be an ink composition containing a polymerizable compound represented by the above general formula (1), and the ink composition B may be an ink composition different from the ink composition containing a polymerizable compound represented by the above general formula (1). Also, both the ink composition A and the ink composition B may be ink compositions containing a polymerizable compound represented by the above general formula (1). The same applies to an ink set including three or more types of ink compositions.

[0109] Further, it may be an ink set in which coloring ink compositions containing colorants are combined. For example, it may be an ink set in which a plurality of ink compositions selected from yellow, magenta, cyan, black, red, orange, violet, blue, green, intermediate colors and light colors of these, a white ink composition containing a white colorant, or a metallic ink containing a fluorescent colorant are combined.

[0110] ≪3. Recording method≫ The recording method according to this embodiment is a recording method in which an ink composition containing a polymerizable compound represented by the general formula (1) is applied onto a substrate by an inkjet method.

[0111] An ink composition containing a polymerizable compound represented by the general formula (1) can form a cured film of an ink composition having good adhesion to various substrates.

[0112] Also, the recording method according to this embodiment may include a discharging step of discharging an ink composition containing a polymerizable compound represented by the general formula (1) onto the surface of a surface-treated resin substrate by inkjet.

[0113] Moreover, it may include an irradiation step of irradiating the ink composition applied to the surface of the substrate with active energy rays. By this irradiation, a cured product of the ink composition is formed on the surface of the substrate. The active energy rays can include electromagnetic waves such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, visible light, infrared rays, X-rays, and γ-rays, as well as active energy rays of electron beams, proton beams, and neutron beams. Among these, active energy rays having a peak wavelength of 365 nm or more and 395 nm or less are preferable.

[0114] The light source for irradiating the active energy rays is not particularly limited, and examples include high-pressure mercury lamps, metal halide lamps, low-pressure mercury lamps, ultra-high-pressure mercury lamps, ultraviolet lasers, sunlight, LED lamps, etc. From the viewpoints of energy saving and high degree of freedom in the design and equipment of the printing apparatus, it is more preferable to use an LED lamp as the light source.

[0115] In order to obtain a surface-treated resin substrate, it may include a pretreatment step of subjecting the surface of the substrate to surface treatment in advance to obtain a surface-treated substrate.

[0116] Examples of this surface treatment method include surface treatments such as corona treatment, frame treatment, plasma treatment, flame treatment, ultraviolet irradiation treatment, chromic acid treatment, and silane coupling treatment. Two or more surface treatments may be combined.

[0117] The substrate to be pretreated may be either a non-absorbent substrate or an absorbent substrate as described below.

[0118] In addition, the inkjet ejection method of the ink composition containing the polymerizable compound represented by the general formula (1) may be any method such as a piezo method or an electrostatic method. The inkjet method may be a serial head method or a line head method, and is not particularly limited.

[0119] Further, the ink composition containing the polymerizable compound represented by the general formula (1) may be applied onto a substrate by means other than inkjet, for example, by spraying, dispenser, or the like.

[0120] ≪4. Method for manufacturing printed matter≫ The above-described recording method can also be defined as a method for manufacturing a printed matter by applying an ink composition containing a polymerizable compound represented by the general formula (1) onto a substrate by an inkjet method. Further, a printed matter can also be manufactured by applying it onto a substrate by means other than inkjet, for example, by spraying, dispenser, or the like.

[0121] ≪5. Printed matter≫ The printed matter obtained by using the ink composition according to the above embodiment includes a substrate (recording medium) and a cured product layer formed on the surface of this substrate (recording medium). And this cured product layer contains the cured product of the polymerizable compound contained in the ink composition according to the above embodiment.

[0122] Here, since the polymerizable compound contained in the ink composition according to the above embodiment contains the polymerizable compound represented by the general formula (1), a cured film with high adhesiveness can be formed on various substrates such as a flexible polyvinyl chloride resin substrate or a hard acrylic resin substrate. Further, even when it does not contain a polymerization initiator or contains a polymerization initiator that does not correspond to the highly concerned substances listed in Annex XIV of the REACH Regulation, it is possible to effectively suppress the decrease in the curability of the ink composition.

[0123] [Substrate (recording medium)] The substrate (recording medium) contained in the recording matter according to the present embodiment is not particularly limited, and may be a non-absorbent substrate such as a resin substrate, a metal plate, or glass, or an absorbent substrate such as paper or cloth, or a substrate with surface coating such as a substrate provided with a receiving layer, and various substrates can be used.

[0124] Examples of the non-absorbent base material include resin base materials such as polyester resins (polyethylene terephthalate, polyethylene naphthalate), polypropylene synthetic paper, polyolefin resins (polypropylene resins, polyethylene resins, etc.), acrylic resins, polystyrene resins, polycarbonate resins, ABS resins, vinyl chloride resins, polyimide resins, etc., metals, metal foil-coated paper, glass, synthetic rubber, natural rubber, etc. Among these, a resin base material containing at least one selected from the group consisting of polypropylene resins, polycarbonate resins, polystyrene resins, polyethylene resins, ABS resins, vinyl chloride resins, polyethylene terephthalate resins, and acrylic resins is preferred.

[0125] In particular, the ink composition containing the polymerizable compound represented by the general formula (1) can form a cured film having high adhesion to a polyvinyl chloride resin or an acrylic resin base material. Therefore, it is particularly preferred that the base material (recording medium) is a polyvinyl chloride resin or an acrylic resin base material.

[0126] Examples of the absorbent base material include blotting paper, medium-quality paper, high-quality paper, synthetic paper, cotton, chemical fiber fabric, silk, hemp, fabric, non-woven fabric, leather, etc.

[0127] Examples of the base material with surface coating include coated paper, art paper, cast paper, lightweight coated paper, lightly coated paper, etc.

[0128] [Cured Film of Ink Composition] The cured film of the ink composition is formed by polymerization of the polymerizable compound contained in the ink composition. For example, when the ink composition contains a coloring material, it becomes a decorative layer or its base layer for forming a desired image. In the present specification, the shape of the "cured film" is not limited to, for example, a flat plate shape or a layer shape, and may have irregularities, may have holes formed in part, or may have a cured film formed on part of the surface, for example. Also, for the sake of convenience, an absorbent substrate that has absorbed the ink composition and is in a state where the cured film of the ink composition is substantially like a part of the substrate is also referred to as the cured film of the ink composition.

[0129] When an ink composition containing a polymerizable compound represented by the general formula (1) is used as an overcoat ink, it becomes an overcoat layer formed on the surface of a recording. In this case, the ink composition for forming the recording layer provided in the recording may be a polymerizable compound ink composition represented by the general formula (1) or may be an ink composition different from the polymerizable compound ink composition represented by the general formula (1).

[0130] The thickness of the cured product (for example, a recording layer or an overcoat layer) of the ink composition containing the polymerizable compound represented by the general formula (1) is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The thickness of the cured product (for example, a recording layer or an overcoat layer) of the ink composition is preferably 100 μm or less, more preferably 90 μm or less, and even more preferably 80 μm or less. The thickness of the cured product of the ink composition is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 90 μm or less, and even more preferably 10 μm or more and 80 μm or less. Desired functions can be imparted to the cured product of the ink composition. The thickness of the cured product is the average value of the thicknesses measured at a plurality of arbitrary locations on the surface of the cured product.

[0131] ≪6. Inkjet recording apparatus≫ The inkjet recording apparatus according to the present embodiment is an inkjet recording apparatus including a storage mechanism filled with an ink composition containing a polymerizable compound represented by the general formula (1).

[0132] The inkjet recording apparatus according to the present embodiment may be an inkjet recording apparatus of a multi-pass system (also referred to as a serial head system) in which an inkjet head reciprocates to eject an ink composition, or may be an inkjet recording apparatus of a single-pass system (also referred to as a line head system) in which an ink composition is ejected onto a recording medium (substrate) without the inkjet head moving.

[0133] The storage mechanism mounted on the inkjet recording apparatus according to the present embodiment is not particularly limited, and examples thereof include containers such as ink bottles, pouches, bag-in-boxes, and drums. Further, these containers may be further housed in a cartridge or the like. The material of the storage container is not particularly limited, and may be a conventionally known resin material, or a material containing a part of a metal material (for example, an aluminum pouch provided with an aluminum vapor deposition layer).

[0134] Also, the ejection method in each ejection unit may be any method such as a piezo method, a thermal method, an electrostatic method, or the like.

[0135] The inkjet recording apparatus according to the present embodiment may include a light source that irradiates active energy rays. The light source that irradiates active energy rays is not particularly limited, and examples thereof include a high-pressure mercury lamp, a metal halide lamp, a low-pressure mercury lamp, an ultra-high-pressure mercury lamp, an ultraviolet laser, sunlight, an LED lamp, and the like. From the viewpoints of energy saving and high degree of freedom in the design and equipment of the printing apparatus, it is more preferable to use an LED lamp as the light source.

Examples

[0136] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these descriptions at all.

[0137] 1. Production of Ink Composition Ink compositions of experimental examples and comparative examples were produced. Specifically, ink compositions of the experimental examples and comparative examples were prepared such that the polymerizable monomer, polymerization initiator, polymerization inhibitor, and coloring material (pigment mill base) were in the proportions shown in the following table. The units in the table are mass%.

[0138] 2. Evaluation of Ink Composition (Storage Stability) The storage stability of the ink compositions of the experimental examples and comparative examples was evaluated. Specifically, the ink compositions of the experimental examples and comparative examples were sealed in a light-shielding glass bottle and stored at 60°C for 7 days, and the occurrence of precipitates and aggregates in the ink composition after storage was visually confirmed. Furthermore, the viscosity of the ink composition before and after storage was measured, and the viscosity change rate was evaluated. [Evaluation Criteria] A: No precipitates or aggregates occurred, and the viscosity change rate was less than 10%. B: No precipitates or aggregates occurred, and the viscosity change rate was 10% or more and less than 20%. C: The occurrence of precipitates or aggregates was confirmed, or the viscosity change rate was 10% or more. A and B are within the usable range.

[0139] (Dischargeability) The dischargeability (inkjet dischargeability) of the ink compositions of the experimental examples and comparative examples was evaluated. Specifically, using a droplet observation device JetXpert manufactured by ImageXpert, the ink compositions of the experimental examples and comparative examples were inkjet discharged from an inkjet head for 10 minutes, and the non-discharge, bending, and scattering discharge defect occurrence rates of the inkjet head were evaluated. [Evaluation Criteria] AA: The discharge defect occurrence rate is less than 1%. A: The discharge defect occurrence rate is 1% or more and less than 3%. B: The discharge defect occurrence rate is 3% or more and less than 10%. C: The discharge defect occurrence rate is 10% or more. AA, A, and B are within the usable range.

[0140] (Sclerosing) The curability of the ink compositions of the examples and comparative examples was evaluated. Specifically, the ink compositions of the examples and comparative examples were ejected onto the surface of a PET film (Toyobo Co., Ltd.'s Cosmo Shine A4300) using an inkjet recording apparatus, "Material Printer DMP-2850" manufactured by Fujifilm Corporation, and irradiated with active energy rays having a peak illuminance of 250 mW / cm 2 and an integrated light quantity of 650 mJ / cm 2 from an LED lamp with a wavelength of 385 nm to form a cured product of the ink composition on the surface of the PET film, and the curability of the cured product was evaluated based on the following evaluation criteria. [Evaluation Criteria] AA: Even when rubbed with a cotton swab, there was no ink adhesion. A: Even when rubbed with a cotton swab, there was almost no ink adhesion. B: Although there was some stickiness, there was no ink adhesion even when rubbed with a cotton swab. C: Ink adhered when rubbed with a cotton swab. AA, A, and B are within the usable range.

[0141] (Rub resistance 1) The rub resistance (rub resistance on a vinyl chloride film) of the ink compositions of the examples and comparative examples was evaluated. Specifically, the ink compositions of the examples and comparative examples were ejected onto the surface of a vinyl chloride film (IMAGin JT5829R: manufactured by MACtac) using an inkjet recording apparatus, "Material Printer DMP-2850" manufactured by Fujifilm Corporation, and irradiated with active energy rays having a peak illuminance of 250 mW / cm 2 and an integrated light quantity of 650 mJ / cm 2 from an LED lamp with a wavelength of 385 nm. The printed surface of the printed matter was rubbed with a test cloth piece under a load of 200 g for 50 reciprocations and evaluated according to the following evaluation criteria. A and B are within the actual usable range. [Evaluation Criteria] AA: The cured film did not peel off, and there was no ink adhesion on the test cloth piece either. A: The cured film hardly peeled off, and there was almost no ink adhesion on the test cloth piece either. B: The cured film was slightly peeled off, and a small amount of ink adhered to the test cloth piece. C: The cured film was peeled off, and ink adhered to the test cloth piece. AA, A, and B are within the usable range.

[0142] (Rub resistance 2) Regarding the ink compositions of the examples and comparative examples, using test pieces prepared in the same manner as for rub resistance 1, the printed surface of the printed matter was rubbed 5 times with a load of 200 g using a test cloth piece to which a 50% by mass aqueous ethanol solution was attached, and evaluated according to the following evaluation criteria. A and B are within the actual usable range. [Evaluation criteria] AA: The cured film was not peeled off, and there was no adhesion of ink to the test cloth piece at all. A: The cured film was hardly peeled off, and there was almost no adhesion of ink to the test cloth piece. B: The cured film was slightly peeled off, and a small amount of ink adhered to the test cloth piece. C: The cured film was peeled off, and ink adhered to the test cloth piece. AA, A, and B are within the usable range.

[0143] (Adhesion 1) Regarding the ink compositions of the examples and comparative examples, the adhesion of the cured film on the PET film was evaluated. Specifically, the ink compositions of the examples and comparative examples were ejected onto the surface of a PET film (Toyobo Co., Ltd. Cosmo Shine A4360) using an inkjet recording apparatus, "Material Printer DMP-2850" manufactured by Fuji Film Co., Ltd., and irradiated with active energy rays having a peak illuminance of 250 mW / cm 2 and an integrated light quantity of 650 mJ / cm 2 . Then, an adhesive tape (Nichiban Co., Ltd. Cellotape (registered trademark) CT-18) was adhered to the surface, and the presence or absence of peeling of the metal foil surface when peeled off was visually confirmed and evaluated according to the following evaluation criteria. [Evaluation criteria] AA: No peeling occurred. A: Almost no peeling occurred. B: Peeling was observed, but it was generally within the allowable range. C: The area of the peeling surface was 1 / 2 or more of the surface to which the adhesive tape was adhered. AA, A, and B are within the usable range.

[0144] (Adhesion 2) Regarding the ink compositions of the examples and comparative examples, the adhesion of the cured film on the acrylic resin plate was evaluated. The ink compositions of the examples and comparative examples were ejected onto the surface of an acrylic resin plate (Mitsubishi Chemical Corporation's Acrylite L) using an inkjet recording apparatus, "Material Printer DMP-2850" manufactured by Fuji Film Co., Ltd., and irradiated with active energy rays having a peak illuminance of 250 mW / cm 2 and an integrated light quantity of 650 mJ / cm 2 from an LED lamp with a wavelength of 385 nm. An adhesive tape (Nichiban Co., Ltd.'s Cellotape (registered trademark) CT-18) was adhered to the surface, and the presence or absence of peeling on the surface of the metal foil when peeled was visually confirmed and evaluated according to the following evaluation criteria. [Evaluation Criteria] AA: No peeling occurred. A: Almost no peeling occurred. B: Peeling was observed, but it was generally within the acceptable range. C: The area of the peeling surface was 1 / 2 or more of the surface to which the adhesive tape was adhered. AA, A, and B are within the usable range.

[0145] (High Concern Substances) Each component included in the ink compositions of the examples and comparative examples was checked to see if it contained substances that were candidates for inclusion in the list of high concern substances. Specifically, an ink composition that did not contain substances that were candidates for inclusion in the list of "substances subject to authorization" (high concern substances) listed in Annex XIV of the REACH Regulation established by the European Union was designated as "A", and an ink composition that contained substances that were candidates for inclusion in the list of "substances subject to authorization" (high concern substances) listed in Annex XIV of the REACH Regulation established by the European Union was designated as "C".

[0146] [Table 1]

[0147]

Table 2

[0148]

Table 3

[0149]

Table 4

[0150] In the table, "PR122" of the pigment (colorant) refers to C.I. Pigment Red 122. In the table, "PV19" of the pigment (colorant) refers to C.I. Pigment Violet 19. In the table, "PR254" of the pigment (colorant) refers to C.I. Pigment Red 254. In the table, "PR202" of the pigment (colorant) refers to C.I. Pigment Red 202. In the table, "PB15:4" of the pigment (colorant) refers to C.I. Pigment Blue 15:4. In the table, "PB15:6" of the pigment (colorant) refers to C.I. Pigment Blue 15:6. In the table, "PY138" of the pigment (colorant) refers to C.I. Pigment Yellow 138. In the table, "PY150" of the pigment (colorant) refers to C.I. Pigment Yellow 150. In the table, "PY155" of the pigment (colorant) refers to C.I. Pigment Yellow 155. In the table, "PG36" of the pigment (colorant) refers to C.I. Pigment Green 36. In the table, "PG58" of the pigment (colorant) refers to C.I. Pigment Green 58. In the table, "PB7" of the pigment (colorant) refers to C.I. Pigment Black 7. In the table, "PW6" of the pigment (colorant) refers to C.I. Pigment White 6. In the table, "D1" of the dispersant (dispersant for coloring material dispersion) is Solsperse 33000 (manufactured by Lubrizol Corporation). In the table, "D2" of the dispersant (dispersant for coloring material dispersion) is BYK 9151 (manufactured by BYK). In the table, "D3" of the dispersant (dispersant for coloring material dispersion) is PX 4701 (manufactured by Efka). In the table, "DMAA" of the polymerizable compound of formula (1) is N,N-dimethylacrylamide. In the table, "DEAA" of the polymerizable compound of formula (1) is N,N-diethylacrylamide. In the table, "DBAA" of the polymerizable compound of formula (1) is N,N-dibutylacrylamide. In the table, "OAA" of the polymerizable compound of formula (1) is N-octylacrylamide. In the table, "AA" of the polymerizable compound of formula (1) is acrylamide. In the table, "HMAA" of the polymerizable compound of formula (1) is N-(hydroxymethyl)acrylamide. In the table, "PHEA" of the monofunctional polymerizable compound is phenoxyethyl acrylate. In the table, "IBXA" of the monofunctional polymerizable compound is isobornyl acrylate. In the table, "TBCH" of the monofunctional polymerizable compound is tert-butyl acrylate. In the table, "CTFA" of the monofunctional polymerizable compound is cyclic trimethylolpropane formal acrylate. In the table, "NOA" of the monofunctional polymerizable compound is n-octyl acrylate. In the table, "PO(3)-TMPTA" of the polyfunctional polymerizable compound is PO-modified trimethylolpropane triacrylate. In the table, "16HDA" of the polyfunctional polymerizable compound is 1,6-hexanediol diacrylate. In the table, "NPGDA" of the polyfunctional polymerizable compound is neopentyl glycol diacrylate. In the table, "PETA" of the polyfunctional polymerizable compound is pentaerythritol tetraacrylate. In the table, "O1" of the polymerizable oligomer is 8UX-122A (acrylate oligomer manufactured by Taisei Fine Chemical Co., Ltd.). In the table, "O2" of the polymerizable oligomer is CN9011 (acrylate oligomer manufactured by Sartomer Company). In the table, "O3" of the polymerizable oligomer is CN996 (acrylate oligomer manufactured by Sartomer Company). In the table, "R1" of the resin is Solvaine CL (vinyl chloride-vinyl acetate copolymer resin manufactured by Nissin Chemical Industry Co., Ltd., weight average molecular weight 25,000). In the table, "R2" of the resin is Daiso Dap (diallyl phthalate resin manufactured by Osaka Soda Co., Ltd., weight average molecular weight 55,000). In the table, "R3" of the resin is Paraloid B60 (acrylic resin manufactured by The Dow Chemical Company, weight average molecular weight 50,000). In the table, "Compound (2-1)" of the polymerization initiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. In the table, "Compound (2-2)" of the polymerization initiator is (2,4,6-trimethylbenzoyl)bis(p-tolyl)phosphine oxide. In the table, "Compound (2-3)" of the polymerization initiator is (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide. In the table, "Compound (2-4)" of the polymerization initiator is ethyl(3-benzoyl-2,4,6-trimethylbenzoyl)phenylphosphinate. In the table, "Compound (2-5)" of the polymerization initiator is 1-(9,9-dibutyl-9H-fluoren-2-yl)-2-methyl-2-(morpholin-4-yl)propan-1-one. In the table, "Compound (2-6)" of the polymerization initiator is 4-benzoyl 4'-methyldiphenyl sulfide. In the table, "Compound (2-7a)" of the polymerization initiator is 2,4-diethylthioxanthone-9-one. In the table, the "compound (2-7b)" of the polymerization initiator is 2-isopropylthioxanthone. In the table, the "initiator 369" of the polymerization initiator is 2-benzyl-2-(N,N-dimethylamino)-1-(4-morpholinophenyl)butan-1-one. In the table, the "initiator TPO" of the polymerization initiator is diphenyl-2,4,6-trimethylbenzoylphosphine oxide.

[0151] As can be seen from the above table, it can be understood that by using an ink composition containing the polymerizable compound represented by the general formula (1), a cured film with high adhesion to various substrates such as acrylic resins can be formed.

[0152] In addition, the ink composition of the example does not contain a polymerization initiator that is a candidate for inclusion as a highly concerned substance in Annex XIV of the REACH Regulation established by the European Union, but it has been confirmed that the curability of the ink composition is good.

[0153] Also, the ink composition of Example 14 contains a binder resin in addition to the ink composition of Example 1, and the content of the polyfunctional polymerizable compound is reduced by the content of the binder resin. The ink composition of Example 14 containing such a predetermined amount of binder resin is even more excellent in curability, abrasion resistance, and adhesion compared to the ink composition of Example 1.

[0154] Similarly, the ink composition of Example 16 contains a binder resin in the ink composition of Example 2, and the content of the polymerizable oligomer is reduced by the content of the resin. The ink composition of Example 16 containing such a predetermined amount of binder resin is even more excellent in curability, abrasion resistance, and adhesion compared to the ink composition of Example 2.

[0155] On the other hand, the ink composition of the comparative example that does not contain the polymerizable compound represented by the general formula (1) has not been able to form a cured film with high adhesion to the acrylic resin substrate.

Claims

1. An active energy ray-curable ink composition that is discharged by an inkjet method, comprising: The ink composition contains a polymerizable compound in an amount of 40% by mass or more and 90% by mass or less based on the total amount of the ink composition, The polymerizable compound is contained in an amount of 5% by mass or more and 75% by mass or less of the total amount of the ink composition, the polymerizable compound being represented by the following general formula (1): Further containing a binder resin which is a non-polymerizable resin having a weight average molecular weight of 10,000 or more, the binder resin contains at least one selected from the group consisting of vinyl chloride-vinyl acetate copolymer resins, diallyl phthalate-based resins, acrylic-based resins, and allyl-based resins; The water content is 5.0% by mass or less based on the total amount of the ink composition. Ink composition. 【Chemistry 1】 (In the formula, R １ is hydrogen or a methyl group, R ２ is hydrogen or an alkyl group having 1 to 10 carbon atoms which may be branched, R ３ is hydrogen or an alkyl group having 1 to 10 carbon atoms which may be branched, and the total number of carbon atoms contained in R 1 R 2 R 3 is 3 or more.

2. The polymerizable compound represented by the general formula (1) is a liquid at 20° C. under 1 atmosphere. The ink composition according to claim 1 .

3. The polymerizable compound represented by the general formula (1) has a vapor pressure of 60 Pa or less at 20° C. The ink composition according to claim 2.

4. The content of the binder resin is 0.05% by mass or more and 25% by mass or less in the total amount of the ink composition. The ink composition according to claim 1 or 2.

5. The ink composition according to claim 1 or 2, wherein the polymerizable compound contains a polyfunctional polymerizable compound, and the polyfunctional polymerizable compound having 4 or more functional groups accounts for 25 mass % or less of the total amount of the ink composition.

6. the total content of the binder resin and the polyfunctional polymerizable compound having 4 or more functional groups is 30 mass % or less of the total amount of the ink composition; The ink composition according to claim 5 .

7. Contains coloring material, It may further contain a dispersant for dispersing the colorant. In the case where the dispersant is contained, the content of the dispersant is less than the content of the coloring material. The ink composition according to claim 1 or 2.

8. It hardens by the active energy rays emitted from the LED lamp. The ink composition according to claim 1 or 2.

9. An ink set comprising the ink composition according to claim 1 or 2.

10. A printed matter comprising the ink composition according to claim 1 or 2 printed on the surface of a substrate.

11. An ink jet recording device comprising a storage mechanism filled with the ink composition according to claim 1 or 2.

12. A recording method comprising ejecting the ink composition according to claim 1 or 2 by an ink-jet method.

13. 3. A method for producing a printed matter by discharging the ink composition according to claim 1 or 2 by an ink-jet method. A method for producing printed matter.

Images