Active energy ray-curable inkjet ink, active energy ray-curable ink set, and image recording method

Abstract

Disclosed are: an active energy ray-curable inkjet ink which contains a bifunctional (meth)acrylate having 4 to 10 carbon atoms and a linear or branched alkylene group, a silicone-based surfactant having a (meth)acryloyl group, a coloring agent, and an acrylic resin having a glass transition temperature of 30°C or more, wherein the content of the bifunctional (meth)acrylate is 20% by mass or more relative to the total mass of this active energy ray-curable inkjet ink; and applications of this active energy ray-curable inkjet ink.

Description

Active energy ray-curable inkjet ink, active energy ray-curable ink set, and image recording method

[0001] The present disclosure relates to an actinic energy ray-curable inkjet ink, an actinic energy ray-curable ink set, and an image recording method.

[0002] 2. Description of the Related Art Conventionally, when an image is recorded on a substrate using ink, a method of curing the ink using active energy rays is known.

[0003] For example, JP 2018-035369 A discloses a composition containing a radical polymerizable compound as component A, a radical polymerization initiator as component B, a color pigment as component C, and a pigment dispersant as component D, in which component A includes benzyl (meth)acrylate and / or 2-phenoxyethyl (meth)acrylate as component A-1, a monofunctional or bifunctional (meth)acrylate compound having an aliphatic hydrocarbon group having 6 or more carbon atoms as component A-2, and a small amount selected from the group consisting of compounds represented by either of the following formulas II and III as component A-3: the total content of Component A-1 is 10 to 50 mass % relative to the total mass of the ink composition, the total content of Component A-2 is 5 to 40 mass % relative to the total mass of the ink composition, and the total content of Component A-3 is 10 to 50 mass % relative to the total mass of the ink composition; and the ink composition contains, as Component C, at least one inorganic pigment selected from the group consisting of Pigment Blue 28, Pigment Red 101, Pigment Yellow 42, and Pigment Yellow 184.

[0004] In some cases, an image recorded by applying ink onto a substrate is required to have excellent abrasion resistance and separability of the image from the substrate.

[0005] The present disclosure has been made in view of the above circumstances, and an object of one embodiment of the present invention is to provide an actinic energy ray-curable inkjet ink, an actinic energy ray-curable ink set, and an image recording method that are capable of producing an image recorded product that is excellent in abrasion resistance and separability of the image from the substrate.

[0006] The present disclosure includes the following aspects. <1> An actinic energy ray-curable inkjet ink comprising: a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms; a silicone-based surfactant having a (meth)acryloyl group; a colorant; and an acrylic resin having a glass transition temperature of 30°C or higher, wherein the content of the bifunctional (meth)acrylate is 20% by mass or more relative to the total amount of the actinic energy ray-curable inkjet ink. <2> The actinic energy ray-curable inkjet ink according to <1>, wherein the mass ratio of the content of the silicone-based surfactant having a (meth)acryloyl group to the content of the acrylic resin is 1 to 10. <3> The actinic energy ray-curable inkjet ink according to <1> or <2>, wherein the mass ratio of the content of the silicone-based surfactant having a (meth)acryloyl group to the content of the acrylic resin is 4 to 7. <4> The actinic energy ray-curable inkjet ink according to any one of <1> to <3>, wherein the content of the silicone surfactant having a (meth)acryloyl group is 0.5% by mass to 10% by mass, based on the total amount of the actinic energy ray-curable inkjet ink. <5> The actinic energy ray-curable inkjet ink according to any one of <1> to <4>, wherein the content of the silicone surfactant having a (meth)acryloyl group is 4% by mass to 7% by mass, based on the total amount of the actinic energy ray-curable inkjet ink. <6> The actinic energy ray-curable inkjet ink according to any one of <1> to <5>, wherein the silicone surfactant having a (meth)acryloyl group contains a polyether structure and a polysiloxane structure, and the mass ratio of the content of the polysiloxane structure to the content of the polyether structure is 0.5 or more. <7> The actinic energy ray-curable inkjet ink according to any one of <1> to <6>, further containing a monofunctional (meth)acrylate having a hydroxyl group. <8> The actinic ray-curable inkjet ink according to any one of <1> to <7>, wherein the acrylic resin has a weight-average molecular weight of 5,000 to 100,000.<9> An actinic energy ray-curable ink set comprising: a first ink that is the actinic energy ray-curable inkjet ink according to any one of <1> to <8>, wherein the colorant is a pigment other than a white pigment; and a second ink that is the actinic energy ray-curable inkjet ink according to any one of <1> to <8>, wherein the colorant is a white pigment. <10> The actinic energy ray-curable ink set according to <9>, wherein, when the first ink and the second ink are equal in mass, the content of the acrylic resin in the first ink is greater than the content of the acrylic resin in the second ink. <11> The actinic energy ray-curable ink set according to <9> or <10>, further comprising a third ink containing at least one acid group-containing compound selected from the group consisting of polymerizable monomers having an acid group and polymers having an acid group. <12> The actinic ray-curable ink set according to <11>, wherein, when the first ink, the second ink, and the third ink are the same in mass, the content of the acrylic resin in the first ink is greater than the content of the acrylic resin in the second ink, and the content of the acrylic resin in the first ink is greater than the content of the acrylic resin in the third ink. <13> An image recording method comprising the steps of applying the actinic ray-curable inkjet ink according to any one of <1> to <8> onto a substrate by inkjet recording, and irradiating the applied actinic ray-curable inkjet ink with actinic rays. <14> An image recording method using the actinic ray-curable ink set according to any one of <9> to <12>, comprising the steps of applying the second ink onto a substrate by inkjet recording and irradiating the applied second ink with actinic rays, applying the first ink onto the substrate to which the second ink has been applied by inkjet recording, and irradiating the applied first ink with actinic rays.

[0007] According to one embodiment of the present invention, there are provided an actinic energy ray-curable inkjet ink, an actinic energy ray-curable ink set, and an image recording method that are capable of obtaining an image recorded product that has excellent abrasion resistance and separability of the image from the substrate.

[0008] The actinic energy ray-curable inkjet ink, actinic energy ray-curable ink set, and image recording method of the present disclosure will be described in detail below.

[0009] In this specification, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this specification, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0010] As used herein, the amount of each component in a composition refers to the total amount of the components in the composition unless otherwise specified, when the composition contains multiple substances corresponding to each component. In this specification, a combination of two or more preferred aspects is a more preferred aspect. As used herein, the term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0011] In this specification, the term "image" refers to a film formed by applying ink in general, and "image recording" refers to the formation of an image (i.e., a film). The concept of "image" in this specification also includes a solid image.

[0012] In this specification, the term "(meth)acrylate" encompasses both acrylate and methacrylate, and the term "(meth)acrylic" encompasses both acrylic and methacrylic.

[0013] An actinic ray-curable inkjet ink (hereinafter also simply referred to as "ink") according to one embodiment of the present disclosure comprises a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms, a silicone surfactant having a (meth)acryloyl group, a colorant, and an acrylic resin having a glass transition temperature of 30°C or higher, and the content of the bifunctional (meth)acrylate is 20% by mass or higher relative to the total amount of the actinic ray-curable inkjet ink.

[0014] For example, by applying an ink according to an embodiment of the present disclosure to a substrate and then irradiating it with active energy rays, an image recording can be obtained in which an ink film is formed as an image on the substrate. The ink according to an embodiment of the present disclosure contains a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms and a silicone-based surfactant having a (meth)acryloyl group, and therefore a polymerization reaction proceeds upon irradiation with active energy rays. In particular, due to the inclusion of a silicone-based surfactant having a (meth)acryloyl group, the ink film formed by the polymerization reaction is thought to have surfactant properties. For example, when an image recording is immersed in a treatment liquid (e.g., an alkaline aqueous solution), the adhesion between the substrate and the ink film decreases, causing the ink film to peel off from the substrate. Because the ink film formed by the ink according to an embodiment of the present disclosure has surfactant properties, it easily floats after peeling off from the substrate, resulting in excellent separability. This allows the substrate from which the image has been separated to be recovered, for example, when the substrate is reused. Furthermore, since the ink according to an embodiment of the present disclosure contains an acrylic resin with a glass transition temperature of 30° C. or higher, it is believed that the ink film has high surface hardness and excellent abrasion resistance.

[0015] On the other hand, JP 2018-035369 A does not anticipate that the content of the bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms will be 20% by mass or more relative to the total amount of the ink.

[0016] Hereinafter, each component contained in the ink according to an embodiment of the present disclosure will be described.

[0017] [Actinic Energy Ray-Curable Inkjet Ink] The ink according to an embodiment of the present disclosure is an active energy ray-curable ink. That is, the ink according to an embodiment of the present disclosure is cured by irradiation with active energy rays. Examples of active energy rays include gamma rays, beta rays, electron beams, ultraviolet rays, and visible light. Of these, ultraviolet rays are preferred. The ink according to an embodiment of the present disclosure is preferably an ultraviolet ray-curable ink.

[0018] <Bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms> The ink according to one embodiment of the present disclosure contains a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms (hereinafter also referred to as a “specific bifunctional (meth)acrylate”).

[0019] The bifunctional (meth)acrylate means a compound having two (meth)acryloyloxy groups.

[0020] The specific bifunctional (meth)acrylate has a linear or branched alkylene group and has 4 to 10 carbon atoms, and therefore the resulting image has excellent abrasion resistance.

[0021] Examples of the linear or branched alkylene group include a methylene group, an ethylene group, an i-propylene group, an n-butylene group, a t-butylene group, and a heptylene group. From the same viewpoint as above, the number of carbon atoms in the linear or branched alkylene group is preferably 6 to 8, and more preferably 6.

[0022] The ink may contain only one type of specific bifunctional (meth)acrylate, or two or more types of specific bifunctional (meth)acrylate.

[0023] Examples of the specific bifunctional (meth)acrylate include 3-methyl-1,5-pentanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol diacrylate, 1,7-heptanediol diacrylate, 1,8-octanediol diacrylate, and 1,9-nonanediol di(meth)acrylate.

[0024] Among these, from the viewpoint of ejection properties, the specific bifunctional (meth)acrylate is preferably at least one selected from the group consisting of 3-methyl-1,5-pentanediol di(meth)acrylate and 1,6-hexanediol diacrylate, and more preferably 3-methyl-1,5-pentanediol di(meth)acrylate.

[0025] The content of the specific bifunctional (meth)acrylate is 20% by mass or more, preferably 20% by mass to 80% by mass, and more preferably 30% by mass to 50% by mass, relative to the total amount of the ink, from the viewpoints of abrasion resistance and odor.

[0026] <Monofunctional (meth)acrylate having a hydroxyl group> The ink according to an embodiment of the present disclosure preferably contains a monofunctional (meth)acrylate having a hydroxyl group (hereinafter also referred to as a "specific monofunctional (meth)acrylate").

[0027] The monofunctional (meth)acrylate means a compound having one (meth)acryloyloxy group.

[0028] The specific monofunctional (meth)acrylate has a hydroxyl group, which prevents water from accumulating locally in the ink film and improves water resistance. Furthermore, the presence of the specific monofunctional (meth)acrylate reduces the oxygen concentration in the ink, suppressing polymerization inhibition by oxygen and improving curability. As a result, the amount of unreacted polymerizable compound can be reduced, and odor can be reduced.

[0029] The ink may contain only one type of specific monofunctional (meth)acrylate, or two or more types of specific monofunctional (meth)acrylate.

[0030] The number of hydroxyl groups contained in the specific monofunctional (meth)acrylate is not particularly limited and is, for example, 1 to 6. From the viewpoint of ink viscosity, the number of hydroxyl groups is preferably 1 to 3, and more preferably 1 or 2.

[0031] From the viewpoint of low odor and low viscosity, the molecular weight of the specific monofunctional (meth)acrylate is preferably 130 to 150.

[0032] Examples of the specific monofunctional (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Among these, the specific monofunctional (meth)acrylate is preferably 4-hydroxybutyl (meth)acrylate from the viewpoints of water resistance and low odor.

[0033] From the viewpoints of water resistance and low odor, the content of the specific monofunctional (meth)acrylate is preferably 30% by mass to 70% by mass, and more preferably 40% by mass to 50% by mass, relative to the total amount of the ink.

[0034] <Other Polymerizable Compounds> The ink according to an embodiment of the present disclosure may contain other polymerizable compounds in addition to the specific bifunctional (meth)acrylate and the specific monofunctional (meth)acrylate, as long as the effects of the present disclosure are not significantly impaired.

[0035] The other polymerizable compound is not particularly limited as long as it is a compound other than the specific bifunctional (meth)acrylate and the specific monofunctional (meth)acrylate and has a polymerizable group.

[0036] From the viewpoint of reactivity with the specific bifunctional (meth)acrylate, the polymerizable group in the other polymerizable compound is preferably a radical polymerizable group, more preferably an ethylenically unsaturated group, and even more preferably a (meth)acryloyloxy group. That is, the other polymerizable compound is preferably a radical polymerizable compound, more preferably an ethylenically unsaturated compound, and even more preferably a (meth)acrylate compound.

[0037] The other polymerizable compound may be a monofunctional polymerizable compound having one polymerizable group, or may be a polyfunctional polymerizable compound having two or more polymerizable groups.

[0038] Monofunctional Polymerizable Compounds Examples of monofunctional polymerizable compounds include monofunctional (meth)acrylates, monofunctional (meth)acrylamides, monofunctional aromatic vinyl compounds, monofunctional vinyl ethers, and monofunctional N-vinyl compounds.

[0039] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, tert-octyl (meth)acrylate, isoamyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-n-butylcyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, bornyl (meth)acrylate, and isobornyl (meth)acrylate. runyl (meth)acrylate, 2-ethylhexyl diglycol (meth)acrylate, butoxyethyl (meth)acrylate, 2-chloroethyl (meth)acrylate, 4-bromobutyl (meth)acrylate, cyanoethyl (meth)acrylate, benzyl (meth)acrylate, butoxymethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-(2-methoxyethoxy)ethyl (meth)acrylate, 2-(2-butoxyethoxy)ethyl (meth)acrylate, 2,2,2-tetrafluoroethyl (meth)acrylate, 1H,1H,2H,2H-perfluorodecyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-tetramethylphenyl (meth)acrylate, 4-chlorophenyl (meth)acrylate, 2-phenoxymethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, glycidyloxybutyl (meth)acrylate, glycidyloxyethyl (meth)acrylate, glycidyloxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, phenyl glycidyl ether (meth)acrylate acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, trimethylsilylpropyl (meth)acrylate, polyethylene oxide monomethyl ether (meth)acrylate, polyethylene oxide (meth)acrylate, polyethylene oxide monoalkyl ether (meth)acrylate, dipropylene glycol (meth)acrylate acrylate, polypropylene oxide monoalkyl ether (meth)acrylate, 2-methacryloyloxyethyl succinate, 2-methacryloyloxyhexahydrophthalic acid, ethoxydiethylene glycol (meth)acrylate, butoxydiethylene glycol (meth)acrylate, trifluoroethyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, ethylene oxide (EO)-modified phenol (meth)acrylate, EO-modified cresol (meth)acrylate, EO-modified nonylphenol (meth)acrylate acrylate, propylene oxide (PO)-modified nonylphenol (meth)acrylate, EO-modified 2-ethylhexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, (3-ethyl-3-oxetanylmethyl) (meth)acrylate, phenoxyethylene glycol (meth)acrylate, 2-carboxyethyl (meth)acrylate, and 2-(meth)acryloyloxyethyl succinate.

[0040] Examples of monofunctional (meth)acrylamides include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-n-butyl(meth)acrylamide, N-t-butyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-methylol(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and (meth)acryloylmorpholine.

[0041] Examples of monofunctional aromatic vinyl compounds include styrene, dimethylstyrene, trimethylstyrene, isopropylstyrene, chloromethylstyrene, methoxystyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, bromostyrene, vinyl benzoic acid methyl ester, 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4-hexylstyrene, 3-octylstyrene, 4-octylstyrene, 3-(2-ethylhexyl)styrene, 4-(2-ethylhexyl)styrene, allylstyrene, isopropenylstyrene, butenylstyrene, octenylstyrene, 4-t-butoxycarbonylstyrene, and 4-t-butoxystyrene.

[0042] Examples of monofunctional vinyl ethers include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, 4-methylcyclohexylmethyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexylmethyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, and phenoxypolyethylene glycol vinyl ether.

[0043] Examples of the monofunctional N-vinyl compound include N-vinyl-ε-caprolactam and N-vinylpyrrolidone.

[0044] - Polyfunctional Polymerizable Compound - Examples of polyfunctional polymerizable compounds include polyfunctional (meth)acrylate compounds and polyfunctional vinyl ethers.

[0045] Examples of polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, EO-modified neopentyl glycol di(meth)acrylate, PO-modified neopentyl glycol di(meth)acrylate, EO-modified hexanediol di(meth)acrylate, PO-modified hexanediol di(meth)acrylate, decanediol di(meth)acrylate, dodecanediol di(meth)acrylate, and glycerin di(meth)acrylate. tris(meth)acrylate, pentaerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane EO adduct tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(meth)acryloyloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly(meth)acrylate, and tris(2-acryloyloxyethyl)isocyanurate.

[0046] Examples of polyfunctional vinyl ethers include 1,4-butanediol divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, and ditrimethylolpropane. trivinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexavinyl ether, EO-added trimethylolpropane trivinyl ether, PO-added trimethylolpropane trivinyl ether, EO-added ditrimethylolpropane tetravinyl ether, PO-added ditrimethylolpropane tetravinyl ether, EO-added pentaerythritol tetravinyl ether, PO-added pentaerythritol tetravinyl ether, EO-added dipentaerythritol hexavinyl ether, and PO-added dipentaerythritol hexavinyl ether.

[0047] Colorant The ink according to one embodiment of the present disclosure contains at least one colorant.

[0048] In the present disclosure, a colorant refers to a substance that, when contained in an ink, makes the ink a chromatic or achromatic ink.

[0049] The colorant may be a chromatic colorant (for example, cyan, magenta, yellow, etc.) or an achromatic colorant (for example, white and black).

[0050] The colorant may be a dye or a pigment. From the viewpoint of durability such as heat resistance, light resistance, and water resistance, the colorant is preferably a pigment.

[0051] When a pigment is used as a colorant, the pigment can be contained in the ink as a pigment dispersion. The pigment dispersion is a liquid obtained by dispersing a pigment in a liquid medium using a dispersant, and contains at least a pigment, a dispersant, and a liquid medium. Details of the dispersant will be described later. The liquid medium may be an organic solvent or a polymerizable compound.

[0052] As the pigment, any of commercially available organic pigments and inorganic pigments can be used, including, for example, pigments described in "Dictionary of Pigments" edited by Seijiro Ito (published in 2000), "Industrial Organic Pigments" by W. Herbst and K. Hunger, and JP-A Nos. 2002-12607, 2002-188025, 2003-26978, and 2003-342503.

[0053] The content of the colorant is preferably 0.5% by mass to 15% by mass, more preferably 1% by mass to 10% by mass, and even more preferably 2% by mass to 5% by mass, based on the total amount of the ink.

[0054] <Dispersant> When a pigment is used as the colorant, the pigment can be contained in the ink as a pigment dispersion. The pigment can be dispersed in a liquid medium using a dispersant. As the dispersant, a commonly known dispersant can be used. From the viewpoint of dispersion stability, the dispersant is preferably a compound having both a hydrophilic structure and a hydrophobic structure.

[0055] Examples of dispersants include low molecular weight dispersants having a molecular weight of less than 1000, such as higher fatty acid salts, alkyl sulfates, alkyl ester sulfates, alkyl sulfonates, sulfosuccinates, naphthalene sulfonates, alkyl phosphates, polyoxyalkylene alkyl ether phosphates, polyoxyalkylene alkyl phenyl ethers, polyoxyethylene polyoxypropylene glycols, glycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene fatty acid amides, and amine oxides.

[0056] Further, examples of the dispersant include high-molecular-weight dispersants having a molecular weight of 1,000 or more obtained by copolymerizing a hydrophilic monomer and a hydrophobic monomer. From the viewpoint of dispersion stability, the hydrophilic monomer is preferably a dissociable group-containing monomer, and is preferably a dissociable group-containing monomer having a dissociable group and an ethylenically unsaturated bond. Examples of the dissociable group-containing monomer include a carboxyl group-containing monomer, a sulfonic acid group-containing monomer, and a phosphate group-containing monomer. From the viewpoint of dispersion stability, the hydrophobic monomer is preferably an aromatic group-containing monomer having an aromatic group and an ethylenically unsaturated bond, or an aliphatic hydrocarbon group-containing monomer having an aliphatic hydrocarbon group and an ethylenically unsaturated bond. The polymer may be either a random copolymer or a block copolymer.

[0057] The dispersant may be a commercially available product. Examples of commercially available products include DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-110, DISPERBYK-111, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-167, DISPERBYK-168, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, and DISPERBYK-182 (all manufactured by BYK Chemie). Examples of the solvent include SOLSPERSE 3000, SOLSPERSE 5000, SOLSPERSE 9000, SOLSPERSE 12000, SOLSPERSE 13240, SOLSPERSE 13940, SOLSPERSE 17000, SOLSPERSE 22000, SOLSPERSE 24000, SOLSPERSE 26000, SOLSPERSE 28000, SOLSPERSE 32000, SOLSPERSE 36000, SOLSPERSE 39000, SOLSPERSE 41000, and SOLSPERSE 71000 (all manufactured by Lubrizol).

[0058] As a dispersing device for dispersing the pigment, a known dispersing device can be used, and examples thereof include a ball mill, a sand mill, a bead mill, a roll mill, a jet mill, a paint shaker, an attritor, an ultrasonic disperser, and a disperser.

[0059] From the viewpoint of dispersion stability, the content of the dispersant relative to the content of the pigment in the ink is preferably 0.05 to 1.0 by mass, and more preferably 0.1 to 0.5.

[0060] <Silicone-Based Surfactant Having a (Meth)acryloyl Group> The ink according to one embodiment of the present disclosure contains at least one silicone-based surfactant having a (meth)acryloyl group.

[0061] When the ink contains a silicone surfactant having a (meth)acryloyl group, the ink film formed has surface activity. For example, when an image-recorded product is immersed in a treatment liquid (e.g., an alkaline aqueous solution), the adhesion between the substrate and the ink film decreases, causing the ink film to peel off from the substrate. Because the ink film has surface activity, it easily floats after peeling off from the substrate, exhibiting excellent separability.

[0062] The number of (meth)acryloyl groups contained in the silicone surfactant having a (meth)acryloyl group may be only one, or may be two or more. From the viewpoint of separability, the number of (meth)acryloyl groups is preferably two or more, and more preferably three or more. The upper limit of the number of (meth)acryloyl groups is not particularly limited, but from the viewpoint of ejection properties, it is, for example, five.

[0063] The silicone surfactant having a (meth)acryloyl group is preferably a polyether-modified polydimethylsiloxane having a (meth)acryloyl group. In the polyether-modified polydimethylsiloxane having a (meth)acryloyl group, the position of the polyether chain is not particularly limited, and may be at one end of the main chain, at both ends of the main chain, or as a side chain. The polyether chain is preferably a polyoxyalkylene chain.

[0064] Commercially available silicone surfactants having a (meth)acryloyl group include, for example, BYK-UV3500, 3505, 3530, 3570, 3575, and 3576 (manufactured by BYK Corporation), Tegorad 2100, 2200, 2250, 2300, 2500, 2600, 2700, 2800, 2010, and 2011 (manufactured by Evonik Corporation), EBECRYL 350 and 1360 (manufactured by Daicel-Allnex Corporation), and KP-410, 411, 412, 413, 414, 415, 416, 418, 420, 422, and 423 (manufactured by Shin-Etsu Silicones Co., Ltd.).

[0065] From the viewpoint of separability, the silicone surfactant having a (meth)acryloyl group preferably contains a polyether structure and a polysiloxane structure, and the mass ratio of the content of the polysiloxane structure to the content of the polyether structure is preferably 0.5 or more, more preferably 0.6 or more, and the upper limit of this mass ratio is, for example, 0.95.

[0066] The mass ratio of the polysiloxane structure content to the polyether structure content was determined by nuclear magnetic resonance spectroscopy (Nuclear Magnetic Resonance; １ 1H-NMR).

[0067] From the viewpoint of separability, the content of the silicone surfactant having a (meth)acryloyl group is preferably 0.5% by mass to 10% by mass, and more preferably 4% by mass to 7% by mass, relative to the total amount of the ink.

[0068] <Acrylic Resin Having a Glass Transition Temperature of 30° C. or Higher> The ink according to an embodiment of the present disclosure contains at least one acrylic resin having a glass transition temperature of 30° C. or higher (hereinafter also referred to as “specific acrylic resin”).

[0069] In the present disclosure, an acrylic resin refers to a resin containing at least one of a structural unit derived from (meth)acrylic acid and a structural unit derived from a (meth)acrylic acid ester.

[0070] When the ink contains the specific acrylic resin, the surface of the ink film becomes hard, which is thought to result in excellent abrasion resistance.

[0071] From the viewpoint of further improving abrasion resistance, the glass transition temperature of the specific acrylic resin is preferably 35° C. or higher, and more preferably 65° C. or higher. There is no particular upper limit to the glass transition temperature, but from the viewpoint of ejection properties, the glass transition temperature is preferably 140° C. or lower, and more preferably 100° C. or lower.

[0072] In the present disclosure, the glass transition temperature of the specific acrylic resin refers to a value measured using differential scanning calorimetry (DSC). As the differential scanning calorimeter (DSC), for example, an EXSTAR6220 (manufactured by SII NanoTechnology, Inc.) is used.

[0073] When the ink contains two or more specific acrylic resins, the glass transition temperature (Tg) refers to the weighted average of the glass transition temperatures of the individual acrylic resins.

[0074] From the viewpoint of abrasion resistance, the specific acrylic resin preferably has a weight average molecular weight of 5,000 to 100,0000, and more preferably 10,000 to 50,000.

[0075] In the present disclosure, the weight-average molecular weight is measured using gel permeation chromatography (GPC). For example, an HLC-8220GPC (manufactured by Tosoh Corporation) is used as the GPC, three TSKgel SuperAWM-H (manufactured by Tosoh Corporation, 6.0 mm I.D. x 15 cm) columns are used, and N-methylpyrrolidone (with 10 mM LiBr added) is used as the eluent. The conditions are a sample concentration of 0.1% by mass, a flow rate of 0.5 mL / min, a sample injection volume of 60 μl, and a measurement temperature of 40°C, and detection is performed using a differential refractive index (RI) detector. A calibration curve is prepared using eight samples of "TSK Standard Polystyrene" manufactured by Tosoh Corporation under the product names: "F-40," "F-20," "F-4," "F-1," "A-5000," "A-2500," "A-1000," and "n-propylbenzene" as standard samples.

[0076] From the viewpoint of achieving a glass transition temperature of 30°C or higher, the specific acrylic resin preferably contains a structural unit derived from at least one selected from the group consisting of a linear or branched aliphatic hydrocarbon group-containing (meth)acrylate and an alicyclic hydrocarbon group-containing (meth)acrylate, and more preferably contains a structural unit derived from a linear or branched aliphatic hydrocarbon group-containing (meth)acrylate and a structural unit derived from an alicyclic hydrocarbon group-containing (meth)acrylate.

[0077] Examples of linear or branched aliphatic hydrocarbon group-containing (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, n-amyl (meth)acrylate, i-amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, i-octyl (meth)acrylate, decyl (meth)acrylate, i-decyl (meth)acrylate, lauryl (meth)acrylate, i-dodecyl (meth)acrylate, stearyl (meth)acrylate, i-stearyl (meth)acrylate, and behenyl (meth)acrylate.

[0078] Examples of alicyclic hydrocarbon group-containing (meth)acrylates include cyclopropyl(meth)acrylate, cyclobutyl(meth)acrylate, cyclopentyl(meth)acrylate, cyclohexyl(meth)acrylate, cycloheptyl(meth)acrylate, cyclooctyl(meth)acrylate, cyclononyl(meth)acrylate, cyclodecyl(meth)acrylate, isobornyl(meth)acrylate, norbornyl(meth)acrylate, and adamantyl(meth)acrylate.

[0079] The mass ratio of the content of the silicone surfactant having a (meth)acryloyl group to the content of the specific acrylic resin is preferably 1 to 10, and more preferably 4 to 7. When the mass ratio is 1 or more, the ejection properties are improved. Furthermore, when the mass ratio is 10 or less, the abrasion resistance is improved.

[0080] From the viewpoint of abrasion resistance, the content of the specific acrylic resin is preferably 0.2% by mass to 3% by mass, and more preferably 0.5% by mass to 1.5% by mass, relative to the total amount of the ink.

[0081] <Polymerization initiator> The ink according to an embodiment of the present disclosure may contain at least one polymerization initiator. The polymerization initiator is preferably a radical polymerization initiator that generates radicals.

[0082] Examples of the radical polymerization initiator include alkylphenone compounds, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds.

[0083] Among these, the polymerization initiator is preferably at least one selected from the group consisting of an acylphosphine compound and a thio compound, more preferably at least one selected from the group consisting of an acylphosphine oxide compound and a thioxanthone compound, and even more preferably a combination of an acylphosphine oxide compound and a thioxanthone compound.

[0084] The acylphosphine oxide compound includes a monoacylphosphine oxide compound and a bisacylphosphine oxide compound.

[0085] Examples of the monoacylphosphine oxide compound include isobutyryldiphenylphosphine oxide, 2-ethylhexanoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, o-toluyldiphenylphosphine oxide, p-t-butylbenzoyldiphenylphosphine oxide, 3-pyridylcarbonyldiphenylphosphine oxide, acryloyldiphenylphosphine oxide, benzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid vinyl ester, acryloyldiphenylphosphine oxide, benzo ... Examples of the diphenylphosphine oxide include dipoylbisdiphenylphosphine oxide, pivaloyldiphenylphosphine oxide, p-toluyldiphenylphosphine oxide, 4-(t-butyl)benzoyldiphenylphosphine oxide, terephthaloylbisdiphenylphosphine oxide, 2-methylbenzoyldiphenylphosphine oxide, versatoyldiphenylphosphine oxide, 2-methyl-2-ethylhexanoyldiphenylphosphine oxide, 1-methyl-cyclohexanoyldiphenylphosphine oxide, pivaloylphenylphosphine acid methyl ester, and pivaloylphenylphosphine acid isopropyl ester.

[0086] Examples of the bisacylphosphine oxide compound include bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-ethoxyphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2-naphthylphosphine oxide, and bis(2,6-dichlorobenzoyl). phenyl)-1-naphthylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-chlorophenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,4-dimethoxyphenylphosphine oxide, bis(2,6-dichlorobenzoyl)decylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-octylphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, bis(2,4,6-trimethylbenzoyl)-2, 5-dimethylphenylphosphine oxide, bis(2,6-dichloro-3,4,5-trimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichloro-3,4,5-trimethoxybenzoyl)-4-ethoxyphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-4-ethoxyphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2- naphthylphosphine oxide, bis(2-methyl-1-naphthoyl)-4-propylphenylphosphine oxide, bis(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide, bis(2-methoxy-1-naphthoyl)-4-ethoxyphenylphosphine oxide, bis(2-chloro-1-naphthoyl)-2,5-dimethylphenylphosphine oxide and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0087] Examples of thioxanthone compounds include thioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-dodecylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 1-methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3-(2-methoxyethoxycarbonyl)thioxanthone, 4-butoxycarbonylthioxanthone, and 1-methyl-2-methyl-2-methylthioxanthone. thioxanthone, 3-butoxycarbonyl-7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-ethoxycarbonyl-3-chlorothioxanthone, 1-ethoxycarbonyl-3-ethoxythioxanthone, 1-ethoxycarbonyl-3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfurylthioxanthone, 3,4-di[2-(2-methoxyethoxy)ethoxycarbonyl]thioxanthone, 1-ethoxycarbonyl-3-phenylsulfurylthioxanthone, thioxanthone, 2-methyl-6-dimethoxymethylthioxanthone, 2-methyl-6-(1,1-dimethoxybenzyl)thioxanthone, 2-morpholinomethylthioxanthone, 2-methyl-6-morpholinomethylthioxanthone, n-allylthioxanthone-3,4-dicarboximide, n-octylthioxanthone-3,4-dicarboximide, N-(1,1,3,3-tetramethylthioxanthone), methylbutyl)thioxanthone-3,4-dicarboximide, 1-phenoxythioxanthone, 6-ethoxycarbonyl-2-methoxythioxanthone, 6-ethoxycarbonyl-2-methylthioxanthone, thioxanthone-2-polyethylene glycol ester, and 2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthone-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride.

[0088] The thioxanthone compound may be a commercially available product, such as the SPEEDCURE series manufactured by Lambson (e.g., SPEEDCURE 7010, SPEEDCURE CPTX, SPEEDCURE ITX, etc.).

[0089] From the viewpoint of further reducing odor, the ink according to an embodiment of the present disclosure preferably contains, as a polymerization initiator, at least one selected from the group consisting of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, and more preferably contains phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide.

[0090] Furthermore, from the viewpoint of further reducing odor, the total content of at least one compound selected from the group consisting of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide (preferably the total content of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide) is preferably 3.5% by mass or more, and more preferably 5% by mass or more, relative to the total amount of the ink. The upper limit of the total content is not particularly limited, but is, for example, 10% by mass.

[0091] Furthermore, from the viewpoint of further reducing odor, the ink according to an embodiment of the present disclosure preferably contains, as a polymerization initiator, a compound having two or more thioxanthone skeletons in the molecule.

[0092] The content of the compound having two or more thioxanthone skeletons in the molecule is preferably 1% by mass to 10% by mass, and more preferably 2% by mass to 8% by mass, relative to the total amount of the ink.

[0093] <Polymerization Inhibitor> The ink according to an embodiment of the present disclosure preferably contains at least one polymerization inhibitor.

[0094] Examples of the polymerization inhibitor include hydroquinone compounds, phenothiazine, catechols, alkylphenols, alkylbisphenols, zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate, copper dibutyldithiocarbamate, copper salicylate, thiodipropionic acid esters, mercaptobenzimidazole, phosphites, nitrosamine compounds, hindered amine compounds, and nitroxyl radicals.

[0095] Among these, the polymerization inhibitor is more preferably a nitrosamine compound.

[0096] Examples of the nitrosamine compound include N-nitroso-N-phenylhydroxylamine aluminum salt and N-nitroso-N-phenylhydroxylamine, with N-nitroso-N-phenylhydroxylamine aluminum salt being preferred as the nitrosamine compound.

[0097] The content of the polymerization inhibitor is preferably 0.05% by mass to 1% by mass relative to the total amount of the ink, from the viewpoint of improving the stability of the ink over time.

[0098] <Additives> The ink according to an embodiment of the present disclosure may contain additives such as a co-sensitizer, an ultraviolet absorber, an antioxidant, an anti-fading agent, a conductive salt, a solvent, and a basic compound, as needed.

[0099] <Physical Properties> The viscosity of the ink is preferably 0.5 mPa·s to 50 mPa·s, more preferably 5 mPa·s to 40 mPa·s, preferably 7 mPa·s to 35 mPa·s, and even more preferably 8 mPa·s to 30 mPa·s. The viscosity is measured at 25°C using a viscometer, for example, a TV-22 viscometer manufactured by Toki Sangyo Co., Ltd.

[0100] The surface tension of the ink is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and even more preferably 25 mN / m to 45 mN / m. The surface tension is measured at 25°C using a surface tensiometer, for example, an automatic surface tensiometer (product name "CBVP-Z" manufactured by Kyowa Interface Science Co., Ltd.) by the plate method.

[0101] [Actinic Energy Ray-Curable Ink Set] An ink set according to an embodiment of the present disclosure includes a first ink and a second ink. The first ink is an embodiment of the ink according to an embodiment of the present disclosure, and the colorant is a pigment other than a white pigment. The second ink is an embodiment of the ink according to an embodiment of the present disclosure, and the colorant is a white pigment.

[0102] Preferred aspects of the first ink and the second ink are the same as the preferred aspects of the ink according to one embodiment of the present disclosure, except for the following.

[0103] Examples of pigments other than white pigments include cyan pigments, magenta pigments, yellow pigments, and black pigments. Examples of white pigments include titanium dioxide, barium sulfate, calcium carbonate, silica, zinc oxide, zinc sulfide, mica, talc, and pearls.

[0104] From the viewpoint of hiding power, the average primary particle diameter of the white pigment is preferably 150 nm or more, and more preferably 200 nm or more. From the viewpoint of ink jetting performance, the average primary particle diameter of the white pigment is preferably 400 nm or less, and more preferably 350 nm or less. The average primary particle diameter of the white pigment is preferably 150 nm to 400 nm.

[0105] In the present disclosure, the average primary particle diameter of the white pigment is a value measured using a transmission electron microscope (TEM). Specifically, 50 particles of the white pigment are randomly selected within the field of view observed with the TEM, and the primary particle diameters of the 50 particles are measured and averaged. As the transmission electron microscope, a 1200EX transmission electron microscope manufactured by JEOL Ltd. can be used.

[0106] From the viewpoint of improving water resistance, when the first ink and the second ink are of the same mass, it is preferable that the content of the specific acrylic resin in the first ink is greater than the content of the specific acrylic resin in the second ink.

[0107] Specifically, the mass ratio of the content of the specific acrylic resin in the first ink to the content of the specific acrylic resin in the second ink is preferably equal to or greater than 2, and more preferably equal to or greater than 5. The upper limit of this mass ratio is, for example, 15.

[0108] The content of the specific acrylic resin in the first ink is preferably 0.2% to 3% by mass, and more preferably 0.5% to 1.5% by mass, relative to the total amount of the first ink. The content of the specific acrylic resin in the second ink is preferably 0.1% to 1% by mass, and more preferably 0.3% to 1% by mass, relative to the total amount of the second ink.

[0109] In addition to the first ink and the second ink, the ink set according to one embodiment of the present disclosure preferably further comprises a third ink containing at least one acid group-containing compound selected from the group consisting of polymerizable monomers having an acid group and polymers having an acid group.

[0110] <Acid Group-Containing Compound> When an acid group reacts with an alkali to form a salt, the water solubility is improved. The third ink is preferably applied directly onto the substrate, and when the third ink contains an acid group-containing compound, the alkali strippability is improved.

[0111] Examples of the acid group in the acid group-containing compound include a carboxy group, a sulfo group, a phosphonic acid group, a phosphoric acid group, and a sulfonamide group.

[0112] -Polymerizable Monomer Having an Acid Group- In the present disclosure, a "monomer" refers to a compound having a molecular weight of less than 1,000. A "polymerizable monomer" refers to a compound having a molecular weight of less than 1,000 and having a polymerizable group. The molecular weight of a monomer can be calculated based on the type and number of atoms constituting the monomer.

[0113] Examples of polymerizable monomers having a carboxy group include 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxypropyl phthalate, 2-(meth)acryloyloxypropyl hexahydrophthalate, 2-carboxyethyl (meth)acrylate, and (meth)acrylic acid.

[0114] Examples of polymerizable monomers having a sulfo group include 2-hydroxy-3-sulfopropyl(meth)acrylate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl(meth)acrylate, 3-sulfopropyl(meth)acrylate, and 4-styrenesulfonic acid.

[0115] Examples of polymerizable monomers having a phosphoric acid group include 2-phosphonooxyethyl (meth)acrylate and 2-(meth)acryloyloxyethyl acid phosphate.

[0116] Among these, the polymerizable monomer having an acid group is preferably a polymerizable monomer having a carboxy group from the viewpoints of improving alkaline strippability, safety, and low viscosity.

[0117] The polymerizable monomer having an acid group may be a monofunctional polymerizable monomer having an acid group or a polyfunctional polymerizable monomer having an acid group. From the viewpoints of improving alkali strippability, safety, and low viscosity, however, it is preferably a monofunctional polymerizable monomer having an acid group, more preferably a monofunctional polymerizable monomer having a carboxy group, and even more preferably a monofunctional (meth)acrylate having a carboxy group.

[0118] -Polymer Having Acid Groups- In the present disclosure, the term "polymer" refers to a compound having a weight-average molecular weight of 1,000 or more.

[0119] Examples of the polymer having an acid group include a (meth)acrylic copolymer, a polyurethane, a polyvinyl alcohol, a polyvinyl butyral, a polyvinyl formal, a polyamide, a polyester, and an epoxy resin. Of these, the polymer having an acid group is preferably a (meth)acrylic copolymer, a polyurethane, or a polyvinyl butyral.

[0120] In the present disclosure, the term "(meth)acrylic copolymer" refers to a copolymer containing (meth)acrylic acid, (meth)acrylic acid esters (e.g., (meth)acrylic acid alkyl esters, (meth)acrylic acid aryl esters, (meth)acrylic acid allyl esters, etc.), (meth)acrylamide, (meth)acrylamide derivatives, and other (meth)acrylic acid derivatives as structural units. Polyurethane refers to a polymer obtained by a condensation reaction between a polyfunctional isocyanate compound having two or more isocyanate groups and a polyhydric alcohol having two or more hydroxyl groups. Polyvinyl butyral refers to a polymer obtained by reacting polyvinyl alcohol, obtained by partial or complete saponification of polyvinyl acetate, with butyraldehyde under acidic conditions. Polyvinyl butyral also includes polymers having functional groups introduced into the molecule.

[0121] The (meth)acrylic copolymer preferably contains a structural unit having an acid group. Among these, the acid group is preferably a carboxy group. Examples of the structural unit having a carboxy group include a structural unit derived from (meth)acrylic acid and a structural unit derived from a structural unit represented by the following formula 1:

[0122]

[0123] In formula (1), R １ represents a hydrogen atom or a methyl group, R ２ represents a single bond or an (n+1)-valent linking group; A represents an oxygen atom or —NR ３ represents -, and R ３ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 1 to 5.

[0124] For preferred embodiments and specific examples of the structural unit represented by formula (1), as well as preferred embodiments of structural units other than the structural unit represented by formula (1), reference can be made to Japanese Patent Nos. 4,668,111 and 5,588,887.

[0125] In particular, the polymer having an acid group preferably contains a structural unit derived from (meth)acrylic acid and a structural unit derived from a (meth)acrylic acid alkyl ester. The number of carbon atoms in the alkyl group contained in the (meth)acrylic acid alkyl ester is preferably 1 to 10, and more preferably 1 to 6.

[0126] The weight average molecular weight of the polymer having an acid group is preferably 1,000 to 1,000,000, more preferably 5,000 to 500,000, and even more preferably 10,000 to 200,000.

[0127] From the viewpoint of further improving alkali strippability, the total content of the acid group-containing compounds is preferably 8% by mass or more, more preferably 10% by mass or more, and even more preferably 14% by mass or more, relative to the total amount of the third ink. The upper limit of this total content is, for example, 20% by mass.

[0128] <Bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms> The third ink preferably contains a specific bifunctional (meth)acrylate. Preferred aspects of the specific bifunctional (meth)acrylate contained in the third ink are the same as the preferred aspects of the specific bifunctional (meth)acrylate contained in the ink according to an embodiment of the present disclosure.

[0129] <Monofunctional (meth)acrylate having a hydroxyl group> The third ink preferably contains a specific monofunctional (meth)acrylate. Preferred aspects of the specific monofunctional (meth)acrylate contained in the third ink are the same as the preferred aspects of the specific monofunctional (meth)acrylate that may be contained in the ink according to an embodiment of the present disclosure.

[0130] <Other Polymerizable Compounds> The third ink may contain other polymerizable compounds.

[0131] Examples of other polymerizable compounds contained in the third ink include the same polymerizable compounds as those contained in the ink according to an embodiment of the present disclosure.

[0132] <Acrylic resin having a glass transition temperature of 30° C. or higher> The third ink preferably contains a specific acrylic resin. Preferred aspects of the specific acrylic resin contained in the third ink are the same as the preferred aspects of the specific acrylic resin contained in the ink according to an embodiment of the present disclosure.

[0133] When the first ink, second ink, and third ink are of the same mass, the content of the specific acrylic resin in the first ink (Mc) is preferably greater than the content of the specific acrylic resin in the second ink (Mw), and the content of the specific acrylic resin in the first ink (Mc) is preferably greater than the content of the specific acrylic resin in the third ink (Mp). Furthermore, the content of the specific acrylic resin in the second ink is more preferably greater than the content of the specific acrylic resin in the third ink. Among these, 1<Mc / Mw≦4 is preferred, and 1.5≦Mc / Mw≦3 is even more preferred. Furthermore, 1<Mc / Mp≦10 is preferred, and 2≦Mc / Mp≦8 is even more preferred.

[0134] For example, when the third ink, the second ink, and the first ink are applied to a substrate in this order, the ink film formed by the first ink will be located on the outermost side. If the content of the acrylic resin in the first ink is greater than the content of the specific acrylic resin in the second ink and the third ink, water resistance will be improved.

[0135] <Polymerization Initiator> The third ink may contain at least one type of polymerization initiator.

[0136] The polymerization initiator contained in the third ink may be the same as the polymerization initiator contained in the ink according to an embodiment of the present disclosure.

[0137] <Polymerization Inhibitor> The third ink preferably contains at least one type of polymerization inhibitor.

[0138] The polymerization inhibitor contained in the third ink may be the same as the polymerization inhibitor contained in the ink according to an embodiment of the present disclosure.

[0139] From the viewpoint of improving the stability of the third ink over time, the content of the polymerization inhibitor is preferably 0.05% by mass to 0.5% by mass relative to the total amount of the third ink.

[0140] <Surfactant> The third ink preferably contains at least one surfactant.

[0141] Examples of surfactants contained in the third ink include those similar to the silicone surfactants having a (meth)acryloyl group contained in the ink according to an embodiment of the present disclosure.

[0142] <Additives> The third ink may contain additives such as a co-sensitizer, an ultraviolet absorber, an antioxidant, an anti-fading agent, a conductive salt, a solvent, and a basic compound, as needed.

[0143] The third ink preferably does not contain a colorant and preferably serves as a primer for removing the image recorded by the first ink and the second ink with an alkali.

[0144] <Physical Properties> The viscosity of the third ink is preferably 0.5 mPa·s to 50 mPa·s, more preferably 5 mPa·s to 40 mPa·s, even more preferably 7 mPa·s to 35 mPa·s, and particularly preferably 8 mPa·s to 30 mPa·s.

[0145] The surface tension of the third ink is preferably 60 mN / m or less, more preferably 20 mN / m to 40 mN / m, and even more preferably 23 mN / m to 30 mN / m.

[0146] [Image Recording Method A] Image recording method A, which is an embodiment of the present disclosure, includes a step of applying the ink (the ink of an embodiment of the present disclosure) onto a substrate using an inkjet recording method, and a step of irradiating the applied ink with actinic energy rays.

[0147] (Step of applying using an inkjet recording method) The type of substrate is not particularly limited, and commonly known substrates can be used as the substrate. Examples of substrates include glass, quartz, and plastic films. Examples of resins constituting the plastic film include cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, acrylic resin, chlorinated polyolefin resin, polyethersulfone resin, polyethylene terephthalate (PET), polyethylene naphthalate, nylon, polyethylene, polystyrene, polypropylene, polycycloolefin resin, polyimide resin, polycarbonate resin, and polyvinyl acetal. The plastic film may be a film containing only one of these resins, or a film containing a mixture of two or more of them.

[0148] The thickness of the substrate is not particularly limited and is, for example, 1 μm to 10 mm. When the substrate is a film, the thickness is preferably 1 μm to 500 μm, more preferably 2 μm to 200 μm, even more preferably 5 μm to 100 μm, and particularly preferably 10 μm to 90 μm. When the substrate is glass, the thickness is preferably 0.1 mm to 10 mm, more preferably 0.15 mm to 8 mm, and even more preferably 0.2 mm to 5 mm.

[0149] The substrate may be a beverage container.

[0150] The material of the beverage container is not particularly limited, and examples thereof include glass and plastic. Among these, the beverage container is preferably a plastic container, and more preferably a PET bottle containing polyethylene terephthalate as a main component.

[0151] The substrate may also be a plastic film that is attached to the surface of a beverage container. The substrate may be subjected to a hydrophilization treatment. Examples of hydrophilization treatments include, but are not limited to, corona treatment, plasma treatment, heat treatment, abrasion treatment, light irradiation treatment (e.g., UV treatment), and flame treatment. Corona treatment can be performed using, for example, a Corona Master (product name "PS-10S", manufactured by Shinko Electric Meter Co., Ltd.). The conditions for the corona treatment may be selected appropriately depending on the type of substrate, etc.

[0152] The inkjet recording method is not particularly limited as long as it is a method capable of recording an image, and any known method can be used. Examples of inkjet recording methods include a charge control method that uses electrostatic attraction to eject ink, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezoelectric element, an acoustic inkjet method that converts an electric signal into an acoustic beam and irradiates the ink with it, thereby ejecting the ink using radiation pressure, and a thermal inkjet (Bubble Jet (registered trademark)) method that heats the ink to form bubbles and uses the resulting pressure.

[0153] Inkjet heads used in inkjet recording methods include a shuttle method in which a short serial head is used and recording is performed while the head is scanned in the width direction of the substrate, and a line method in which a line head is used in which recording elements are arranged corresponding to the entire area of ​​one side of the substrate.

[0154] The line method allows for pattern formation over the entire surface of a substrate by scanning the substrate in a direction intersecting the direction of the recording element arrangement, eliminating the need for a transport system such as a carriage for scanning a short head. Furthermore, the line method does not require complex scanning control of the carriage movement and the substrate, and only the substrate moves, making it possible to achieve faster recording speeds than the shuttle method.

[0155] The volume of ink droplets ejected from the inkjet head is preferably 1 pL (picoliter) to 100 pL, more preferably 3 pL to 80 pL, and even more preferably 3 pL to 50 pL.

[0156] (Step of irradiating the applied ink with active energy rays) Examples of active energy rays include gamma rays, beta rays, electron beams, ultraviolet rays, and visible light. Of these, ultraviolet rays are preferred as the active energy rays.

[0157] The peak wavelength of the ultraviolet light is, for example, preferably 200 nm to 405 nm, more preferably 250 nm to 400 nm, and even more preferably 300 nm to 400 nm.

[0158] As light sources for ultraviolet irradiation, various lasers such as mercury lamps, gas lasers, and solid-state lasers are mainly used, and discharge lamps such as mercury lamps, metal halide lamps, and ultraviolet fluorescent lamps are widely known. In addition, semiconductor light sources such as UV-LEDs (ultraviolet light-emitting diodes) and UV-LDs (ultraviolet laser diodes) are small, have a long life, are highly efficient, and are low cost, and are expected to be light sources for ultraviolet irradiation. Among these, the light source for ultraviolet irradiation is preferably a metal halide lamp, a high-pressure mercury lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp, or a UV-LED.

[0159] In the present disclosure, polymerizing only a portion of the polymerizable monomers in the ink is also referred to as “pre-curing,” and the irradiation of active energy rays for pre-curing is also referred to as “pinning exposure.” In the present disclosure, polymerizing substantially all of the polymerizable compounds in the ink is also referred to as “main curing,” and the irradiation of active energy rays for main curing is also referred to as “main exposure.”

[0160] In the step of irradiating the ink with actinic radiation, it is preferable to temporarily cure the ink and then fully cure it. Specifically, it is preferable to apply the ink, then subject the ink to pinning exposure, and finally subject the ink to full exposure.

[0161] The reaction rate of the ink after pinning exposure is preferably 10% to 80%.

[0162] Here, the reaction rate of the ink means the polymerization rate of the polymerizable compound contained in the ink, which is determined by high performance liquid chromatography.

[0163] By ensuring that the ink reaction rate is 10% or more, insufficient dot spreading is suppressed, and as a result, the graininess of the final image is improved.

[0164] Furthermore, by keeping the ink reactivity at 80% or less, interference between ink dots is suppressed, resulting in an improvement in the quality of the image that is ultimately obtained.

[0165] The reaction rate of the ink is preferably 15% or more from the viewpoint of further improving the graininess of the final image.

[0166] From the viewpoint of further improving the image quality of the final image obtained, the ink reactivity is preferably 75% or less, more preferably 50% or less, preferably 40% or less, more preferably 30% or less, and even more preferably 25% or less.

[0167] The reaction rate of the ink after the main exposure is preferably more than 80% and not more than 100%, more preferably 85% to 100%, and even more preferably 90% to 100%. When the reaction rate is more than 80%, the adhesion is further improved.

[0168] The ink reactivity is determined by the following method. A substrate is prepared that has been subjected to the operations up to the end of irradiation of the ink with actinic energy rays. A sample piece (hereinafter referred to as post-irradiation sample piece) measuring 20 mm x 50 mm is cut out from the region of this substrate where the ink film is present. The cut post-irradiation sample piece is immersed in 10 mL of THF (tetrahydrofuran) for 24 hours to obtain an eluate in which the ink has dissolved. The amount of polymerizable compound (hereinafter referred to as "post-irradiation monomer amount X1") is determined for the obtained eluate by high performance liquid chromatography. Separately, the same operation as above is carried out except that the ink on the substrate is not irradiated with actinic energy rays, and the amount of polymerizable compound (hereinafter referred to as "unirradiated monomer amount X1") is determined. The ink reactivity (%) is determined based on the post-irradiation monomer amount X1 and the unirradiated monomer amount X1 using the following formula: Ink reactivity (%) = ((unirradiated monomer amount X1 - post-irradiation monomer amount X1) / unirradiated monomer amount X1) x 100

[0169] The exposure dose of the active energy rays for pinning exposure is set to 10 mJ / cm from the viewpoint of making it easier to achieve the above-mentioned ink reaction rate. ２ ~100 mJ / cm ２ and preferably 20 mJ / cm ２ ~60 mJ / cm ２ It is more preferable that:

[0170] The exposure dose of the active energy rays for the main exposure is 50 mJ / cm from the viewpoint of completely curing the ink. ２ ~1000mJ / cm ２ and preferably 200 mJ / cm ２ ~800 mJ / cm ２ It is more preferable that:

[0171] In the main exposure, from the viewpoint of improving adhesion to the substrate, it is preferable to irradiate with active energy rays in an atmosphere with an oxygen concentration of less than 1% by volume, more preferably 0.5% by volume or less, and even more preferably 0.3% by volume or less.

[0172] In the step of irradiating with active energy rays, from the viewpoint of image quality, it is preferable to irradiate with active energy rays within 0.1 to 5 seconds from the time the ink lands. When pinning exposure and main exposure are performed, it is preferable to irradiate with active energy rays for pinning exposure within 0.1 to 5 seconds from the time the ink lands. It is more preferable that the time from the time the ink lands to the irradiation with active energy rays (when pinning exposure and main exposure are performed, active energy rays for pinning exposure) is within 0.2 to 1 second.

[0173] [Image Recording Method B] Image recording method B, which is an embodiment of the present disclosure, uses the ink set described above (the ink set, which is an embodiment of the present disclosure), and includes the steps of applying the second ink onto a substrate by inkjet recording; irradiating the applied second ink with actinic energy rays; applying the first ink onto the substrate to which the second ink has been applied by inkjet recording; and irradiating the applied first ink with actinic energy rays.

[0174] The type of substrate, the method of applying the ink by ink jet recording, and the method of irradiating with active energy rays are the same as those in the image recording method A described above.

[0175] The differences from image recording method A will be explained below.

[0176] In image recording method B, it is preferable to apply the second ink, then subject the second ink to pinning exposure, apply the first ink onto the provisionally cured second ink, then apply the first ink, then subject the first ink to pinning exposure, and finally subject the first ink to main exposure. By provisionally curing the second ink, the image quality of the final image obtained is improved.

[0177] Image recording method B may further include the steps of applying a third ink onto a substrate by inkjet recording and irradiating the applied third ink with actinic energy rays. In this case, it is preferable that the second ink is applied onto the substrate to which the third ink has been applied. It is also preferable that after applying the third ink, the third ink is subjected to pinning exposure, after applying the second ink, the second ink is subjected to pinning exposure, the first ink is applied onto the provisionally cured second ink, after applying the first ink, the first ink is subjected to pinning exposure, and finally, the main exposure is performed.

[0178] Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to the following examples as long as it does not depart from the gist of the disclosure.

[0179] Examples 1 to 34, Comparative Examples 1 to 5 Preparation of First Ink and Second Ink To prepare the first ink (cyan ink), a cyan pigment dispersion was first prepared. To prepare the second ink (white ink), a white pigment dispersion was first prepared.

[0180] A cyan pigment (30 parts by mass), SOLSPERSE 32000 (9 parts by mass) as a dispersant, 3MPDDA (60 parts by mass) as a dispersion medium, and UV22 (1 part by mass) as a polymerization inhibitor were charged into a dispersing machine, Motor Mill M50 (manufactured by Eiger), and a dispersion treatment was carried out using zirconia beads having a diameter of 0.65 mm at a peripheral speed of 9 m / s for 4 hours, thereby obtaining a cyan pigment dispersion.

[0181] In preparing the second ink (white ink), first, a white pigment dispersion was prepared.

[0182] A white pigment (60 parts by mass), SOLSPERSE 32000 (9 parts by mass) as a dispersant, 3MPDDA (30 parts by mass) as a dispersion medium, and UV22 (1 part by mass) as a polymerization inhibitor were charged into a dispersing machine, Motor Mill M50 (manufactured by Eiger GmbH), and a dispersion treatment was carried out using zirconia beads having a diameter of 0.65 mm at a peripheral speed of 9 m / s for 4 hours, thereby obtaining a white pigment dispersion.

[0183] Details of the components contained in the cyan pigment dispersion and the white pigment dispersion are as follows.

[0184] Cyan pigment: C.I. Pigment Blue 15:4 (product name "Heliogen (registered trademark) Blue D 7110 F", Sun Chemical (DIC Corporation)) White pigment: titanium oxide (product name "KRONOS 2300", KRONOS Corporation) SOLSPERSE 32000: polyethyleneimine-based dispersant (product name "SOLSPERSE 32000", Lubrizol Corporation) 3MPDDA: 3-methyl-1,5-pentanediol diacrylate (product name "SR341", Sartomer Corporation) UV22: A mixture of 2,6-bis(1,1-dimethylethyl)-4-(phenylmethylene)-2,5-cyclohexadiene-1-one and propoxylated glycerin triacrylate (product name "IRGASTAB UV-22", manufactured by BASF)

[0185] Although UV22 contains propoxylated glycerin triacrylate as another polymerizable compound, the content of propoxylated glycerin triacrylate is very small, so it is listed in the "polymerization inhibitor" column in the table.

[0186] Next, the prepared cyan pigment dispersion was mixed with the components shown in Tables 2 to 9 below, so that the content (mass%) of each component was as shown in Tables 2 to 9. The mixture was stirred for 20 minutes at 5,000 rpm at 25°C using a mixer (product name "L4R", manufactured by Silverson) to obtain a first ink. The prepared white pigment dispersion was mixed with the components shown in the tables below to obtain a second ink. The mixture was stirred for 20 minutes at 5,000 rpm at 25°C using a mixer (product name "L4R", manufactured by Silverson) to obtain a second ink.

[0187] [Preparation of third ink] The components shown in Tables 2 to 9 below were mixed so that the content (mass %) of each component was as shown in Tables 2 to 9. The mixture was stirred for 20 minutes at 25°C and 5,000 rpm using a mixer (product name "L4R", manufactured by Silverson) to obtain a third ink.

[0188] Details of each component listed in Tables 2 to 9 are as follows. Speedcure 7010L (manufactured by Lambson) was used to prepare the ink. Speedcure 7010L is a mixture of Speedcure 7010 and EOTMPTA, with a mixing ratio of 1:1 by mass. Speedcure 7010 is a polymerization initiator and EOTMPTA is another polymerizable compound, so they will be explained in the columns for polymerization initiators and other polymerizable compounds, respectively.

[0189] <Specific bifunctional (meth)acrylate> The specific bifunctional (meth)acrylate is a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms. 3MPDDA: As described above. HDDA: 1,6-hexanediol diacrylate (product name "Viscoat #230", manufactured by Osaka Organic Chemical Industry Ltd.) NDDA: 1,9-hexanediol diacrylate (product name "Viscoat #260", manufactured by Osaka Organic Chemical Industry Ltd.) DDDA: 1,10-decanediol diacrylate (product name "SR595", manufactured by Sartomer) BDDA: 1,4-butanediol diacrylate (product name "Viscoat #195", manufactured by Osaka Organic Chemical Industry Ltd.)

[0190] <Specific Monofunctional (Meth)acrylate> The specific monofunctional (meth)acrylate is a monofunctional (meth)acrylate having a hydroxyl group. 4-HBA: 4-hydroxybutyl acrylate (product name "4-HBA", manufactured by Osaka Organic Chemical Industry Ltd.)

[0191] <Polymerizable monomer having an acid group> A-SA: 2-acryloyloxyethyl succinic acid (product name "NK Ester A-SA", manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0192] <Polymers having acid groups> Polymer A: Binder A described in paragraph 0225 of Japanese Patent No. 5588887 (structural units derived from methacrylic acid:structural units derived from methyl methacrylate=20:80)

[0193] <Other Polymerizable Compounds> The other polymerizable compounds are polymerizable compounds other than the specific bifunctional (meth)acrylates, the specific monofunctional (meth)acrylates, and the polymerizable monomers having an acid group. CTFA: cyclic trimethylolpropane formal acrylate (product name "Viscoat #200", manufactured by Osaka Organic Chemical Industry Ltd.) EOTMPTA: trimethylolpropane EO adduct triacrylate (50% by mass contained in "product name "Speedcure 7010L", manufactured by Lambson) PEG400DA: polyethylene glycol diacrylate (product name "SR344", manufactured by Sartomer)

[0194] <Polymerization initiator> BAPO: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (product name "Omnirad 819", manufactured by IGM Resins B.V.) Speedcure 7010: 1,3-di({α-[1-chloro-9-oxo-9H-thioxanthen-4-yl)oxy]acetylpoly[oxy(1-methylethylene)]}oxy)-2,2-bis({α-[1-methylethylene)]}oxymethyl)propane (50% by mass contained in "product name "Speedcure 7010L", manufactured by Lambson")

[0195] <Polymerization inhibitor> UV12: N-nitroso-N-phenylhydroxylamine aluminum salt (product name "FLORSTAB UV-12", manufactured by Kromachem) UV22: As described above.

[0196] <Silicone-Based Surfactant> The mass ratio M of the content of the polysiloxane structure to the content of the polyether structure is as follows. Tegorad 2010: (meth)acryloyl group-containing silicone surfactant (product name "Tegorad 2010", manufactured by Evonik, mass ratio M: 0.627119) Tegorad 2500: (meth)acryloyl group-containing silicone surfactant (product name "Tegorad 2500", manufactured by Evonik, mass ratio M: 0.937369) Tegorad 2100: (meth)acryloyl group-containing silicone surfactant (product name "Tegorad 2100", manufactured by Evonik, mass ratio M: 0.355208) Tegorad 2200N: (meth)acryloyl group-containing silicone surfactant (product name "Tegorad 2200N", manufactured by Evonik, mass ratio M: 0.36319) Tegorad 2250: (meth)acryloyl group-containing silicone surfactant (product name "Tegorad 2250", manufactured by Evonik, mass ratio M: 0.451587) Tegorad 2300: (meth)acryloyl group-containing silicone surfactant (product name "Tegorad 2300", manufactured by Evonik, mass ratio M: 0.612617)

[0197] <Colorants> Cyan pigment: as described above White pigment: as described above

[0198] <Dispersant> SOLSPERSE 32000: As described above.

[0199] <Acrylic resin> BR113: Product name "Dianal BR113", manufactured by Mitsubishi Chemical Corporation, glass transition temperature 75°C, weight average molecular weight 30,000 Polymer A to Polymer I: Acrylic resins synthesized by the following method

[0200] -Synthesis of Polymer A- 20 g of a mixed solution of methyl methacrylate and isobornyl acrylate and 30 g of methyl ethyl ketone were introduced into a nitrogen-purged three-neck flask. The mixture was stirred with a stirrer (Three-One Motor, manufactured by Shinto Scientific Co., Ltd.) and heated to 65°C while flowing nitrogen into the flask. 80 mg of 2,2-azobis(2,4-dimethylvaleronitrile) (product name "V-65", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to the mixed solution, and the mixture was stirred at 65°C for 30 minutes. 80 mg of V-65 was added, and the mixture was stirred at 65°C for an additional hour. The resulting reaction solution was poured into 1,000 mL of hexane with stirring, and the resulting precipitate was dried by heating to obtain Polymer A. The weight-average molecular weight of Polymer A was 30,000 to 35,000.

[0201] -Synthesis of Polymer B to Polymer I- Polymers B to I were obtained using polymerizable monomers with masses (g) shown in Table 1 in the same manner as in the synthesis of Polymer A, by appropriately changing the amount of V-65 added and the heating time. Generally, increasing the amount of V-65 decreases the weight-average molecular weight of the resulting polymer. Decreasing the amount of V-65 increases the weight-average molecular weight of the resulting polymer. Furthermore, increasing the heating time increases the weight-average molecular weight of the resulting polymer. Shortening the heating time decreases the weight-average molecular weight of the polymer.

[0202] Details of the polymerizable monomers used in the synthesis of Polymers A to I are as follows.

[0203] Isobornyl methacrylate (product name "Light Ester IB-X", manufactured by Kyoeisha Chemical Co., Ltd.) t-Butyl methacrylate (product name "Light Ester TB", manufactured by Kyoeisha Chemical Co., Ltd.) 2-Phenoxyethyl methacrylate (product name "SR340", manufactured by Sartomer) 2-Ethylhexyl methacrylate (product name "Light Ester EH", manufactured by Kyoeisha Chemical Co., Ltd.) Isodecyl methacrylate (product name "Light Ester ID", manufactured by Kyoeisha Chemical Co., Ltd.) n-Lauryl methacrylate (product name "Light Ester L", manufactured by Kyoeisha Chemical Co., Ltd.) n-Butyl methacrylate (product name "Light Ester NB", manufactured by Kyoeisha Chemical Co., Ltd.) Methyl methacrylate (product name "M0087", manufactured by Tokyo Chemical Industry Co., Ltd.)

[0204] - Weight average molecular weight of acrylic resin ("Mw" in Table 1) - The weight average molecular weight of each acrylic resin was measured using high performance liquid chromatography (HPLC) (product name "HLC-8220GPC", manufactured by Tosoh Corporation). Three TSKgel SuperAWM-H columns (manufactured by Tosoh Corporation, 6.0 mm I.D. x 15 cm) were used, and N-methylpyrrolidone (with 10 mM LiBr added) was used as the eluent. The conditions were a sample concentration of 0.1% by mass, a flow rate of 0.5 mL / min, a sample injection volume of 60 μL, and a measurement temperature of 40°C, and detection was performed using a refractive index (RI) detector. The calibration curve was prepared using eight samples of "TSK Standard Polystyrene" manufactured by Tosoh Corporation under the product names: "F-40," "F-20," "F-4," "F-1," "A-5000," "A-2500," "A-1000," and "n-propylbenzene" as standard samples.

[0205] - Glass Transition Temperature of Acrylic Resin ("Tg" in Table 1) - The glass transition temperature of the acrylic resin was measured using a differential scanning calorimeter (DSC) (product name "EXSTAR6220", manufactured by SII NanoTechnology Inc.).

[0206]

[0207] Image recording was performed using the prepared first ink, second ink, and third ink. In image recording A, image recording was performed using only the first ink. In image recording B, image recording was performed using the first ink and the third ink. In image recording C, image recording was performed using the first ink, the second ink, and the third ink.

[0208] (Image Recording A) The first ink (cyan ink) was applied to an acrylic substrate (Acryl manufactured by Nippon Acrylace Co., Ltd.) using an inkjet recording device (product name "CylinderJET" manufactured by Tritec Corporation) and an inkjet head (product name "KM1800i" manufactured by Konica Minolta, Inc.). Specifically, the first ink was applied to a 7 cm x 5 cm rectangle under conditions of a droplet volume of 10.5 pL (picoliter) and a resolution of 600 x 600 dpi (dots per inch), thereby recording a 100% solid image with a thickness of 4 μm to 6 μm. After applying the first ink, an LED light source attached to the inkjet recording device was used to record an exposure amount of 100 mJ / cm. ２ ~1000mJ / cm ２ The substrate was irradiated with ultraviolet light at a wavelength of 385 nm. A UV-LED irradiator (product name "G4B", manufactured by Kyocera Corporation) with a peak wavelength of 385 nm was used as the LED light source. In the image recording, the gap between the acrylic substrate surface and the inkjet head was adjusted to 0.5 mm to 1 mm. The ejection voltage was also adjusted to adjust the ejected droplet velocity to 7 m / s to 9 m / s.

[0209] (Image Recording B) The third ink (primer) was applied to the body of a PET bottle (product name "PET500 Round" manufactured by Kokugo Co., Ltd.) using an inkjet recording device (product name "CylinderJET" manufactured by Tritec Corporation) and an inkjet head (product name "KM1800i" manufactured by Konica Minolta, Inc.). Specifically, the third ink was applied to a surface measuring 7 cm in the longitudinal direction of the PET bottle and 5 cm in the circumferential direction of the PET bottle at a droplet volume of 10.5 pL (picoliter) and a resolution of 600 x 600 dpi (dots per inch), thereby recording a 100% solid image with a thickness of 4 μm to 6 μm. Furthermore, under the same conditions as for the application of the third ink, the first ink (cyan ink) was applied to the surface to which the third ink had been applied, thereby recording a 100% solid image with a thickness of 4 μm to 6 μm. After the application of the third ink and after the application of the first ink, an exposure amount of 10 mJ / cm was applied using an LED light source attached to the inkjet recording apparatus. ２ ~100 mJ / cm ２ The bottle was irradiated with ultraviolet light at a wavelength of 385 nm. A UV-LED irradiator (product name "G4B", manufactured by Kyocera Corporation) with a peak wavelength of 385 nm was used as the LED light source. The PET bottle with the recorded image was then placed in an exposure machine. The PET bottle was set sideways. The exposure machine is capable of rotating the PET bottle. The entire image recorded on the PET bottle was exposed using the LED light source while being rotated. Exposure amount: 50 mJ / cm ２ ~500 mJ / cm ２ The ink was then irradiated with ultraviolet light at a temperature of 1000 K to completely cure the third ink and the first ink, thereby obtaining a recorded image. During the image recording, the gap between the PET bottle surface and the inkjet head was adjusted to 0.5 mm to 1 mm. The ejection voltage was also adjusted to obtain an ejected droplet velocity of 7 m / s to 9 m / s.

[0210] (Image Recording C) The third ink (primer) was applied to the body of a PET bottle (product name "PET500 Maru" manufactured by Kokugo Co., Ltd.) using an inkjet recording device (product name "CylinderJET" manufactured by Tritec Corporation) and an inkjet head (product name "KM1800i" manufactured by Konica Minolta, Inc.). Specifically, the third ink was applied to a surface measuring 7 cm in the longitudinal direction of the PET bottle and 5 cm in the circumferential direction of the PET bottle at a droplet volume of 10.5 pL (picoliter) and a resolution of 600 x 600 dpi (dots per inch), thereby recording a 100% solid image with a thickness of 4 to 6 μm. Furthermore, under the same conditions as for the application of the third ink, the second ink (white ink) was applied to the surface to which the third ink had been applied, thereby recording a 100% solid image with a thickness of 4 to 6 μm. Furthermore, under the same conditions as for the application of the third ink, the first ink (cyan ink) was applied to the surface to which the third ink and the second ink had been applied, and a 100% solid image with a thickness of 4 μm to 6 μm was recorded. After the application of the third ink, after the application of the second ink, and after the application of the first ink, an LED light source attached to the inkjet recording apparatus was used to record an image with an exposure amount of 10 mJ / cm. ２ ~100 mJ / cm ２ The bottle was irradiated with ultraviolet light at a wavelength of 385 nm. A UV-LED irradiator (product name "G4B", manufactured by Kyocera Corporation) with a peak wavelength of 385 nm was used as the LED light source. The PET bottle with the recorded image was then placed in an exposure machine. The PET bottle was set sideways. The exposure machine is capable of rotating the PET bottle. The entire image recorded on the PET bottle was exposed using the LED light source while being rotated. The exposure dose was 50 mJ / cm2 to 500 mJ / cm2. ２ The ink was then irradiated with ultraviolet light at a temperature of 1000 K. The third ink, second ink, and first ink were completely cured to obtain a recorded image. During the image recording, the gap between the PET bottle surface and the inkjet head was adjusted to 0.5 mm to 1 mm. The ejection voltage was also adjusted to obtain an ejected droplet velocity of 7 m / s to 9 m / s.

[0211] [Evaluation] For each Example and Comparative Example, the image recorded matter obtained by image recording A, image recording B, and image recording C was evaluated for abrasion resistance, separation ability, water resistance, and odor. The ejection properties of the first ink and the second ink were also evaluated. In Tables 2 to 9, Evaluation 1 lists the evaluation results of abrasion resistance, separation ability, water resistance, and odor using the image recorded matter obtained by image recording A, as well as the evaluation results of the ejection properties of the first ink. In Tables 2 to 9, Evaluation 2 lists the evaluation results of abrasion resistance, separation ability, water resistance, and odor using the image recorded matter obtained by image recording B. In Tables 2 to 9, Evaluation 3 lists the evaluation results of abrasion resistance, separation ability, water resistance, and odor using the image recorded matter obtained by image recording C, as well as the evaluation results of the ejection properties of the second ink. The evaluation methods are as follows.

[0212] <Separability (Image Recorded Matter Obtained by Image Recording A)> The obtained image recorded matter was cut into 0.5 cm x 0.5 cm squares to prepare 20 samples. Each sample was stirred in a 1.5% by mass aqueous sodium hydroxide solution at 85°C. The image recorded matter obtained by Image Recording A was stirred for 30 minutes, while the image recorded matter obtained by Image Recording B or Image Recording C was stirred for 10 minutes. The samples were then left to stand for 10 minutes, and the ink film floating on the surface was collected. The samples that had precipitated in the aqueous sodium hydroxide solution were washed with water and dried in a thermostatic chamber at 30°C for 12 hours. After drying, the condition of each sample was visually confirmed. Each sample in which the ink film completely peeled off was given a plus 5 points. Each sample in which the ink film partially peeled off was given a plus 2 points. Each sample in which the ink film did not peel off at all was given a minus 5 points. The 20 samples were assigned scores based on the above criteria, and the separability was evaluated based on the total score. The evaluation criteria are as follows: 5: Total score is 91 to 100 points. 4: Total score is 81 to 90 points. 3: Total score is 51 to 80 points. 2: Total score is 10 to 50 points. 1: Total score is 9 points or less.

[0213] <Abrasion Resistance> A white cotton cloth for rubbing was attached to the tip of the friction element, and the image recording surface of the image-recorded material was rubbed back and forth 100 times using a Gakushin-type abrasion fastness tester (product name "AB-301", manufactured by Tester Sangyo Co., Ltd.) without a weight. The staining of the white cotton cloth and discoloration of the image-recorded material were evaluated using a staining gray scale. 100% cotton Kanakin No. 3 was used as the white cotton cloth for rubbing. The staining of the white cotton cloth and discoloration of the image-recorded material in terms of dry abrasion fastness were evaluated according to the following evaluation criteria. The staining gray scale is expressed in nine levels according to JIS L 0805 (2005): 1, 1-2, 2, 2-3, 3, 3-4, 4, 4-5, and 5. 5: 5 level 4: 4-5 level 3: 4 level 2: 2-3, 3, 3-4 level 1: 1, 1-2, 2 level

[0214] <Water Resistance> The obtained image-recorded product was immersed in ion-exchanged water at 10°C to 25°C. After 24 hours, the image-recorded product was removed from the ion-exchanged water. The image-recorded surface of the removed image-recorded product was scratched with a pencil (hardness H), and visually confirmed whether or not image peeling had occurred. If image peeling had not occurred, the image-recorded product was immersed again in ion-exchanged water, removed after 24 hours, and the image-recorded surface of the image-recorded product was scratched with a pencil (hardness H). This operation was repeated a maximum of nine times. If image peeling had occurred, the next operation was not performed. The evaluation criteria were as follows: Rank 3 or higher was a level that was not problematic in practical use. 5: No image peeling had occurred after 8 operations. 4: Image peeling had occurred after 8 operations. 3: Image peeling had occurred after 7 operations. 2: Image peeling had occurred after 6 operations. 1: Image peeling had occurred after 5 or fewer operations.

[0215] <Odor> An image sample measuring 10 cm x 10 cm was cut out from the obtained image recording. Within 10 minutes after the completion of image recording, the image sample was placed in a large-mouthed 500 mL glass bottle, tightly sealed, and left for 3 days. After 3 days, a sensory evaluation of odor was conducted. Ten subjects scored "no odor" with 50 points, "very slight odor" with 47 points, "slight odor" with 30 points, "definite odor" with 20 points, and "strong odor" with 0 points, and the odor was evaluated based on the total score. The evaluation criteria are as follows: Rank 3 or higher is a level that is not problematic for practical use. 5: 495 points or higher 4: 485 points or higher but less than 495 points 3: 470 points or higher but less than 485 points 2: 450 points or higher but less than 470 points 1: Less than 450 points

[0216] <Ejection Performance> The ejection performance of the first ink or the second ink was evaluated using an inkjet recording device (product name "CylinderJET", manufactured by Tritec Corporation) and an inkjet head (product name "KM1800i", manufactured by Konica Minolta, Inc.). The number of ejection nozzles before image recording was counted using a nozzle check pattern. In addition, after 10 minutes of image recording, the number of ejection nozzles after image recording was counted using a nozzle check pattern. The number of ejection nozzles before image recording and the number of ejection nozzles after image recording were used to calculate the reduction in the number of ejection nozzles. The same test was performed three times, and the ejection performance was evaluated based on the average value N of the reduction in the number of ejection nozzles. The evaluation criteria were as follows: Reduction in number of ejection nozzles = Number of ejection nozzles before image recording - Number of ejection nozzles after image recording 5: N is less than 1. 4: N is 1 or more and less than 3. 3: N is 3 or more and less than 4. 2: N is 4 or more and less than 7. 1: N is 7 or more.

[0217] Tables 2 to 9 show the evaluation results.

[0218] In Tables 2 to 9, "Ms / Mc" means the mass ratio of the content of the silicone surfactant having a (meth)acryloyl group to the content of the acrylic resin.

[0219]

[0220]

[0221]

[0222]

[0223]

[0224]

[0225]

[0226]

[0227]

[0111] As shown in Tables 2 to 9, in Examples 1 to 34, a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms, a silicone surfactant having a (meth)acryloyl group, a colorant, and an acrylic resin having a glass transition temperature of 30°C or higher were contained, and the content of the bifunctional (meth)acrylate was 20% by mass or more with respect to the total amount of the actinic energy ray-curable inkjet ink. Therefore, it was found that the obtained image recorded matter had excellent abrasion resistance and separability.

[0228] On the other hand, Comparative Example 1 did not contain an acrylic resin with a glass transition temperature of 30°C or higher, and therefore was found to have poor abrasion resistance. Comparative Example 2 did not contain a silicone surfactant having a (meth)acryloyl group, and therefore was found to have poor separability. Comparative Example 3 did not contain an acrylic resin with a glass transition temperature of less than 30°C, and therefore was found to have poor abrasion resistance. Comparative Example 4 did not contain a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms, and therefore was found to have poor abrasion resistance. Comparative Example 5 did not contain a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms, and therefore the ink could not be ejected, and an image recording could not be obtained.

[0229] In Example 1, the mass ratio of the content of the silicone surfactant having a (meth)acryloyl group to the content of the acrylic resin in the first ink was 4 or more, and therefore it was found that the ejection properties were superior to those of Example 5. Furthermore, in Example 1, the mass ratio of the content of the silicone surfactant having a (meth)acryloyl group to the content of the acrylic resin in the first ink was 7 or less, and therefore it was found that the abrasion resistance was superior to that of Example 4.

[0230] In Example 29, the mass ratio of the content of polysiloxane structures to the content of polyether structures in the silicone-based surfactant having a (meth)acryloyl group contained in the first ink was 0.5 or more, and therefore it was found to have superior separability compared to Examples 30 and 31.

[0231] In Example 8, the weight average molecular weight of the acrylic resin contained in the first ink was 5,000 to 100,000, and therefore it was found that the scratch resistance was superior to that of Examples 12 and 13.

[0232] Example 101 A first ink C1 (cyan ink), a first ink M1 (magenta ink), a first ink Y1 (yellow ink), a first ink K1 (black ink), a second ink W1 (white ink), and a third ink P1 (clear ink) were prepared.

[0233] The first ink C1 was the first ink in Example 1. The second ink W1 was the second ink in Example 1. The third ink P1 was the third ink in Example 1.

[0234] [Preparation of First Inks M1, Y1, K1] First, a magenta pigment dispersion, a yellow pigment dispersion, and a black pigment dispersion were prepared by replacing the cyan pigment in the preparation of the cyan pigment dispersion described above with a magenta pigment, a yellow pigment, and a black pigment, respectively.

[0235] Details of the magenta pigment, yellow pigment, and black pigment are as follows.

[0236] Magenta pigment: C.I. Pigment RED 122, product name "TRM-33", manufactured by Dainichiseika Color & Chemicals Co., Ltd. Yellow pigment: C.I. Pigment Yellow 185, product name "Paliotol Yellow D 1155", manufactured by Sun Chemical (DIC) Black pigment: Carbon black, product name "MOGUL E", manufactured by CABOT

[0237] Next, each of the prepared magenta pigment dispersions, yellow pigment dispersions, and black pigment dispersions was mixed with the components shown in Table 10 so that the content of each component was the content (mass %) shown in Table 10. The mixture was stirred for 20 minutes at 25°C and 5,000 rpm using a mixer (product name "L4R", manufactured by Silverson) to obtain first inks M1, Y1, and K1.

[0238]

[0239] [Image recording] The third ink P1 was applied to the body of a PET bottle (product name "PET500 Maru", manufactured by Kokugo Co., Ltd.) using an inkjet recording device (product name "CylinderJET", manufactured by Tritec Corporation) and an inkjet head (product name "KM1800i", manufactured by Konica Minolta, Inc.) Specifically, the third ink P1 was applied to a surface measuring 7 cm in the longitudinal direction of the PET bottle and 5 cm in the circumferential direction of the PET bottle under conditions of a droplet volume of 10.5 pL (picoliter) and a resolution of 600 x 600 dpi (dots per inch), thereby recording a 100% solid image with a thickness of 4 to 6 μm. Furthermore, under the same conditions as for applying the third ink P1, the second ink W1, the first ink K1, the first ink C1, the first ink M1, and the first ink Y1 were applied in this order onto the surface to which the third ink P1 had been applied, and 100% solid images with a thickness of 4 μm to 6 μm were recorded, respectively. After applying the third ink P1, the second ink W1, the first ink K1, the first ink C1, the first ink M1, and the first ink Y1, an exposure amount of 10 mJ / cm was recorded using an LED light source attached to the inkjet recording apparatus. ２ ~100 mJ / cm ２The bottle was irradiated with ultraviolet light at a wavelength of 385 nm. A UV-LED irradiator (product name "G4B", manufactured by Kyocera Corporation) with a peak wavelength of 385 nm was used as the LED light source. The PET bottle with the recorded image was then placed in the exposure machine. The PET bottle was set sideways. The exposure machine is capable of rotating the PET bottle. The entire image recorded on the PET bottle was exposed using the LED light source while being rotated. Exposure amount: 50 mJ / cm ２ ~500 mJ / cm ２ The inks were irradiated with ultraviolet light at a temperature of 1000 KJ / 2000 K to completely cure the third ink P1, second ink W1, first ink K1, first ink C1, first ink M1, and first ink Y1, thereby obtaining a recorded image. During the image recording, the gap between the PET bottle surface and the inkjet head was adjusted to 0.5 mm to 1 mm. The ejection voltage was also adjusted to provide an ejected droplet velocity of 7 m / s to 9 m / s.

[0240] The obtained image recording matter was evaluated for abrasion resistance, separation property, water resistance, and odor using the same evaluation methods as in Example 1. The ejection properties of the first inks M1, Y1, and K1 were also evaluated using the same evaluation methods as in Example 1. All evaluation results were "5."

[0241] The disclosure of Japanese Patent Application No. 2023-013499, filed on January 31, 2023, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. The composition comprises a bifunctional (meth)acrylate having a linear or branched alkylene group having 4 to 10 carbon atoms, a silicone surfactant having a (meth)acryloyl group, a colorant, and an acrylic resin having a glass transition temperature of 30°C or higher, The content of the bifunctional (meth)acrylate is 20% by mass or more based on the total amount of the actinic energy ray-curable inkjet ink.

2. 2. The actinic ray-curable inkjet ink according to claim 1, wherein a mass ratio of the content of the silicone surfactant having a (meth)acryloyl group to the content of the acrylic resin is 1 to 10.

3. 2. The actinic ray-curable inkjet ink according to claim 1, wherein a mass ratio of the content of the silicone surfactant having a (meth)acryloyl group to the content of the acrylic resin is 4 to 7.

4. 2. The actinic energy ray-curable inkjet ink according to claim 1, wherein a content of the silicone surfactant having a (meth)acryloyl group is 0.5% by mass to 10% by mass with respect to a total amount of the actinic energy ray-curable inkjet ink.

5. 2. The actinic energy ray-curable inkjet ink according to claim 1, wherein a content of the silicone surfactant having a (meth)acryloyl group is 4% by mass to 7% by mass with respect to a total amount of the actinic energy ray-curable inkjet ink.

6. The silicone surfactant having a (meth)acryloyl group contains a polyether structure and a polysiloxane structure, 2. The actinic ray-curable inkjet ink according to claim 1, wherein a mass ratio of the content of the polysiloxane structure to the content of the polyether structure is 0.5 or more.

7. The actinic ray-curable inkjet ink according to claim 1 , further comprising a monofunctional (meth)acrylate having a hydroxyl group.

8. 2. The actinic ray-curable inkjet ink according to claim 1, wherein the acrylic resin has a weight average molecular weight of 5,000 to 100,000.

9. a first ink, which is the actinic energy ray-curable inkjet ink according to any one of claims 1 to 8, wherein the colorant is a pigment other than a white pigment; an active energy ray-curable ink set comprising: a second ink, the active energy ray-curable inkjet ink according to any one of claims 1 to 8, wherein the colorant is a white pigment;

10. When the first ink and the second ink are the same in mass, 10. The actinic ray curable ink set according to claim 9, wherein the content of the acrylic resin in the first ink is greater than the content of the acrylic resin in the second ink.

11. 10. The actinic ray-curable ink set according to claim 9, further comprising a third ink containing at least one acid group-containing compound selected from the group consisting of polymerizable monomers having an acid group and polymers having an acid group.

12. The third ink further contains an acrylic resin having a glass transition temperature of 30°C or higher; When the first ink, the second ink, and the third ink are the same in mass, the content of the acrylic resin in the first ink is greater than the content of the acrylic resin in the second ink; 12. The actinic ray-curable ink set according to claim 11, wherein the content of the acrylic resin in the first ink is greater than the content of the acrylic resin in the third ink.

13. applying the actinic ray-curable inkjet ink according to any one of claims 1 to 8 onto a substrate by an inkjet recording method; and irradiating the applied actinic energy ray-curable inkjet ink with actinic energy rays.

14. The actinic ray curable ink set according to claim 9 is used, applying the second ink onto a substrate by an inkjet recording method; irradiating the applied second ink with actinic energy rays; applying the first ink onto the substrate to which the second ink has been applied by an inkjet recording method; irradiating the applied first ink with actinic energy rays; An image recording method comprising: