Water transfer inkjet ink set, water transfer inkjet prints

Abstract

To provide an inkjet ink set for water transfer which prevents bleeding, and enables manufacture of a printed matter for water transfer in a shorter time than a conventional inkjet ink set for water transfer.SOLUTION: An inkjet ink set for water transfer for printing water transfer paper in which a concealing layer, a design layer, and a protective layer are laminated on a base material coated with a water-soluble resin contains first to third inkjet inks, wherein the first inkjet ink contains a coloring pigment, a di- or higher functional (meth)acrylate monomer or oligomer, and a photopolymerization initiator, the second inkjet ink contains a coloring pigment, a di- or higher functional (meth)acrylate monomer or oligomer, and a photopolymerization initiator, the third inkjet ink contains an acrylic resin polymer having Tg of 20-50°C, a fluorine-based surface modifier, and an organic solvent, and surface tensions (S1 to S3) of the first to third inkjet inks satisfy a relation of S1>S2>S3.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water transfer inkjet ink set and a water transfer inkjet print. More specifically, the present invention relates to a water transfer inkjet ink set and a water transfer inkjet print that are less likely to bleed and can produce water transfer prints in a shorter time than conventional methods. [Background technology]

[0002] Conventionally, water transfer sheets for transferring various designs onto a substrate have been known (for example, the water transfer sticker of Patent Document 1 and the transfer mark sheet of Patent Document 2). The water transfer sticker of Patent Document 1 is formed from a substrate, a release layer, a first protective layer, a design layer consisting of an inkjet printed layer, and a second protective layer. The transfer mark sheet of Patent Document 2 comprises a substrate on which a water-soluble adhesive layer is formed, an ink layer, and a peelable resin layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-55269 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-196245 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the water transfer sticker described in Patent Document 1 has a first protective layer as a base and a peelable second protective layer formed by screen printing. To create a high-definition design by screen printing, the design layer must be formed by multi-stage screen printing, which requires a drying process after each step. Therefore, the water transfer sticker described in Patent Document 1 takes a long time to manufacture. Furthermore, the transfer mark sheet described in Patent Document 2 has an ink layer formed using a solvent-based ink. Therefore, this transfer mark sheet cannot be printed in multiple colors at the same time. Furthermore, the applied colors are prone to bleeding.

[0005] The present invention has been made to solve these problems, and has an object to provide a water transfer inkjet ink set and a water transfer inkjet print that are less likely to bleed and can produce water transfer prints in a shorter time than conventional methods. [Means for solving the problem]

[0006] The water transfer inkjet ink set and water transfer inkjet print of the present invention, which solve the above problems, mainly comprise the following components.

[0007] (1) A water transfer inkjet ink set for printing water transfer paper having a concealing layer, a design layer formed on the concealing layer, and a protective layer formed on the design layer laminated on a substrate coated with a water-soluble resin, the inkjet ink set comprising a first inkjet ink for forming the concealing layer, a second inkjet ink for forming the design layer, and a third inkjet ink for forming the protective layer, the first inkjet ink comprising (1a) a color pigment, (1b) at least one of a difunctional or higher functional (meth)acrylate monomer or a difunctional or higher functional (meth)acrylate oligomer, and (1c) a photopolymerization initiator, the second inkjet ink comprises (2a) a color pigment, (2b) at least one of a di- or higher functional (meth)acrylate monomer or a di- or higher functional (meth)acrylate oligomer, (2c) a photopolymerization initiator, and (2e) a surface conditioner; and the third inkjet ink comprises (3a) an acrylic resin polymer having a glass transition temperature (Tg) of 20 to 50°C, (3b) a fluorine-containing surface conditioner, and (3c) an organic solvent, wherein the surface tensions (S1) of the first inkjet ink, (S2) of the second inkjet ink, and (S3) of the third inkjet ink satisfy the relationship S1>S2>S3.

[0008] With this configuration, the concealing layer and the design layer have excellent solvent resistance to the organic solvent in the protective layer. Therefore, the water transfer inkjet ink set makes it easy to produce water transfer inkjet prints from which the protective layer can be easily peeled off during water transfer. Furthermore, the design layer has excellent UV curing properties. Therefore, the design layer is less likely to bleed colors even when simultaneously printed. Furthermore, the protective layer exhibits excellent peelability and moderate elongation, firmness, and stiffness. Therefore, the resulting water transfer inkjet prints are easy to handle during water transfer.

[0009] (2) The water transfer inkjet ink set according to (1), wherein the first inkjet ink contains (1b) at least one of a difunctional or higher (meth)acrylate monomer and a difunctional or higher (meth)acrylate oligomer in a total content of 60% by mass or more of the total resin components, and the second inkjet ink contains (2b) at least one of a difunctional or higher (meth)acrylate monomer and a difunctional or higher (meth)acrylate oligomer in a total content of 60% by mass or more of the total resin components.

[0010] With this configuration, the design layer has better UV curing properties. Therefore, the design layer is less likely to bleed colors even when printed simultaneously. Furthermore, the concealing layer and the design layer have better solvent resistance to the organic solvent in the protective layer. Therefore, the water transfer inkjet ink set makes it easier to produce water transfer inkjet prints in which the protective layer is more easily peeled off during water transfer.

[0011] (3) The inkjet ink set for water transfer printing according to (1) or (2), wherein the first inkjet ink contains (1d) an organic solvent, and the second inkjet ink contains (2d) an organic solvent.

[0012] With this configuration, the inkjet ink can be easily adjusted to a low viscosity, and has excellent ejection properties from the inkjet head.

[0013] (4) The water transfer inkjet ink set according to (3), wherein (1d) the organic solvent is a glycol ether-based solvent having a boiling point of 150 to 250°C, and (2d) the organic solvent is a glycol ether-based solvent having a boiling point of 150 to 250°C.

[0014] According to this configuration, the water transfer inkjet ink set makes it easy to produce a water transfer inkjet print in which the protective layer is more easily peeled off during water transfer.

[0015] (5) The water transfer inkjet ink set according to any one of (1) to (4), wherein the organic solvent (3c) is a glycol ether solvent having a boiling point of 150 to 250°C.

[0016] According to this configuration, the water transfer inkjet ink set makes it easy to produce a water transfer inkjet print in which the protective layer is more easily peeled off during water transfer.

[0017] (6) A water transfer inkjet print comprising a water transfer paper formed on a substrate coated with a water-soluble resin, the water transfer paper comprising a concealing layer, a design layer formed on the concealing layer, and a protective layer formed on the design layer, the concealing layer, the design layer, and the protective layer being layers to which the first inkjet ink, the second inkjet ink, and the third inkjet ink of the inkjet ink set described in any one of (1) to (5) are applied, respectively.

[0018] According to this configuration, the water transfer inkjet print is less likely to bleed and can be produced in a shorter time than conventional methods. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a water transfer inkjet ink set and a water transfer inkjet print that are less likely to bleed and that can produce a water transfer print in a shorter time than conventional methods. DETAILED DESCRIPTION OF THE INVENTION

[0020] <Water transfer inkjet ink set> A water transfer inkjet ink set (hereinafter also referred to as an ink set) according to one embodiment of the present invention is an ink set for printing water transfer paper having a substrate coated with a water-soluble resin, a hiding layer, a design layer formed on the hiding layer, and a protective layer formed on the design layer, laminated thereon. The ink set includes a first inkjet ink for forming the hiding layer, a second inkjet ink for forming the design layer, and a third inkjet ink for forming the protective layer. The first inkjet ink includes (1a) a color pigment, (1b) at least one of a difunctional or higher functional (meth)acrylate monomer or a difunctional or higher functional (meth)acrylate oligomer, and (1c) a photopolymerization initiator. The second inkjet ink includes (2a) a color pigment, (2b) at least one of a difunctional or higher functional (meth)acrylate monomer or a difunctional or higher functional (meth)acrylate oligomer, (2c) a photopolymerization initiator, and (2e) a surface conditioner. The third inkjet ink contains (3a) an acrylic resin polymer having a glass transition temperature (Tg) of 20 to 50°C, (3b) a fluorine-based surface modifier, and (3c) an organic solvent. The surface tensions of the first inkjet ink (S1), the second inkjet ink (S2), and the third inkjet ink (S3) are in the relationship S1>S2>S3. Each of these will be described below.

[0021] (First inkjet ink) The first inkjet ink is an ink for forming a hiding layer on a substrate coated with a water-soluble resin, and contains (1a) a color pigment, (1b) at least one of a difunctional or higher functional (meth)acrylate monomer or a difunctional or higher functional (meth)acrylate oligomer, and (1c) a photopolymerization initiator.

[0022] (1a) Color pigments The color pigment may be any of various inorganic or organic pigments. Examples of inorganic pigments include oxides, composite oxides, hydroxides, sulfides, ferrocyanides, chromates, carbonates, silicates, phosphates, carbons (carbon black), and metal powders. Examples of organic pigments include nitroso pigments, dye lakes, azo lakes, insoluble azo pigments, monoazos, disazos, condensed azo pigments, benzimidazolones, phthalocyanines, anthraquinones, perylenes, quinacridones, dioxazines, isoindolines, azomethines, and pyrrolopyrroles. These pigments may be used in combination.

[0023] In order to further improve the weather resistance of the resulting water transfer inkjet print, it is preferable to use an inorganic pigment as the color pigment of this embodiment, and it is also preferable to use an organic pigment from the viewpoint of achieving excellent color development of the resulting water transfer inkjet print.

[0024] The color pigment may be dispersed in various dispersants. The color pigment of this embodiment is more preferably a pigment dispersed in a polymer dispersant, since the resulting water transfer inkjet print has better water repellency.

[0025] The polymer dispersant is not particularly limited. Examples of the polymer dispersant include polyoxyalkylene polyalkylene polyamine, vinyl polymer or copolymer, acrylic polymer or copolymer, polyester, polyamide, polyimide, polyurethane, amino polymer, etc. The polymer dispersants may be used in combination.

[0026] The acid value of the polymeric dispersant is preferably 5 mgKOH / g or more, more preferably 15 mgKOH / g or more. The amine value of the polymeric dispersant is preferably 15 mgKOH / g or more, more preferably 25 mgKOH / g or more. Polymeric dispersants with these acid values ​​and amine values ​​have excellent adsorption properties for color pigments. In this embodiment, the acid value refers to the acid value per gram of dispersant solid content and can be calculated by potentiometric titration in accordance with JIS K 0070. The amine value refers to the amine value per gram of dispersant solid content and can be calculated by converting the value calculated by potentiometric titration using a 0.1 mol / L aqueous hydrochloric acid solution into the equivalent amount of potassium hydroxide.

[0027] When a color pigment is contained, the content of the color pigment in the first inkjet ink is preferably 0.1% by mass or more, and more preferably 1% by mass or more. Furthermore, the content of the color pigment in the first inkjet ink is preferably 30% by mass or less, and more preferably 20% by mass or less. By keeping the content of the color pigment within the above range, the resulting water transfer inkjet print tends to exhibit sufficient color development while maintaining ejection stability.

[0028] (1b) At least one of a di- or higher functional (meth)acrylate monomer or a di- or higher functional (meth)acrylate oligomer The first inkjet ink of this embodiment contains at least one of a di- or higher functional (meth)acrylate monomer and a di- or higher functional (meth)acrylate oligomer.

[0029] The difunctional or higher functional (meth)acrylate monomer is not particularly limited. Examples of the difunctional or higher functional (meth)acrylate monomer include triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, bisphenol A PO adduct diacrylate, and neopentyl glycol hydroxypivalate. Examples of suitable (meth)acrylate monomers include difunctional (meth)acrylate monomers such as diacrylate and polytetramethylene glycol diacrylate, and polyfunctional (meth)acrylate monomers having two or more functional groups, such as trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, glycerin propoxy triacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol ethoxy tetraacrylate, and caprolactam-modified dipentaerythritol hexaacrylate. Among these, preferred (meth)acrylate monomers having two or more functional groups are 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and neopentyl glycol diacrylate, due to their excellent adhesion to the substrate. The difunctional (meth)acrylate monomers may be used in combination.

[0030] The content of the di- or higher functional (meth)acrylate monomer is not particularly limited. For example, the content of the di- or higher functional (meth)acrylate monomer in the first inkjet ink is preferably 1% by mass or more, and more preferably 10% by mass or more. The content of the di- or higher functional (meth)acrylate monomer in the first inkjet ink is preferably 90% by mass or less, and more preferably 80% by mass or less. When the content of the di- or higher functional (meth)acrylate monomer is within the above range, the inkjet ink has excellent curability when exposed to ultraviolet light, easily wets and spreads on various substrates, and can have improved adhesion to the substrate.

[0031] The di- or higher functional (meth)acrylate oligomer is not particularly limited, and examples thereof include urethane (meth)acrylate oligomers, polyester (meth)acrylate oligomers, and epoxy (meth)acrylate oligomers.

[0032] The urethane (meth)acrylate oligomer is a urethane (meth)acrylate oligomer obtained by reacting a polyol with a diisocyanate compound to form a compound having a terminal isocyanate group, and then reacting the resulting compound with hydroxyethyl (meth)acrylate. The polyol is a polyether polyol obtained by adding ethylene oxide, propylene oxide, or the like to a polyol such as a diol such as ethylene glycol or propylene glycol, a triol such as glycerin, trimethylolpropane, hexanetriol, or triethanolamine, a tetraol such as diglycerin or pentaerythritol, or a hexaol such as sorbitol, a condensation polyester polyol, a lactone polyester polyol, or a polyester polyol such as polycarbonate diol.

[0033] The polyester (meth)acrylate oligomer is an ester of a polyester polyol such as ethylene adipate, diethylene adipate, or butylene adipate with (meth)acrylic acid.

[0034] Epoxy (meth)acrylate oligomers include adducts of diallyl ether and (meth)acrylic acid, adducts of hexanediol and glycidyl (meth)acrylate, adducts of glycerin and glycidyl (meth)acrylate, adducts of phthalic acid and glycidyl (meth)acrylate, adducts of polyethylene glycol and glycidyl (meth)acrylate, and adducts of polypropylene glycol and glycidyl (meth)acrylate.

[0035] The weight-average molecular weight of the difunctional or higher (meth)acrylate oligomer is not particularly limited. For example, the weight-average molecular weight is preferably 1,000 or more, and more preferably 5,000 or more. The weight-average molecular weight is preferably 50,000 or less, and more preferably 40,000 or less.

[0036] The content of the difunctional or higher functional (meth)acrylate oligomer is not particularly limited. For example, the content of the difunctional or higher functional (meth)acrylate monomer in the first inkjet ink is preferably 1% by mass or more, and more preferably 10% by mass or more. Furthermore, the content of the difunctional or higher functional (meth)acrylate monomer in the first inkjet ink is preferably 50% by mass or less, and more preferably 40% by mass or less. By having the content of the difunctional or higher functional (meth)acrylate monomer within the above range, the first inkjet ink can be easily adjusted to a relatively low viscosity, and has excellent ejection properties from an inkjet head. Furthermore, the first inkjet ink has excellent curability when exposed to ultraviolet light.

[0037] In the first inkjet ink of this embodiment, the total content of the difunctional or higher (meth)acrylate monomer and the difunctional or higher (meth)acrylate oligomer is preferably 60% by mass or more, and more preferably 70% by mass or more, of the total resin components. When the total content is within the above range, the resulting hiding layer has better solvent resistance to the organic solvent in the protective layer. Therefore, the ink set of this embodiment makes it easy to produce printed matter in which the protective layer is more easily peeled off during water transfer.

[0038] (1c) Photopolymerization initiator The photopolymerization initiator is added to the inkjet ink in order to appropriately cure the inkjet ink by ultraviolet light or the like.

[0039] The photopolymerization initiator is not particularly limited. Examples of the photopolymerization initiator include alkylphenone compounds, benzophenone compounds, benzoin compounds, thioxanthone compounds, halomethylated triazine compounds, halomethylated oxadiazole compounds, biimidazole compounds, oxime ester compounds, titanocene compounds, benzoic acid ester compounds, and acridine compounds. The photopolymerization initiators may be used in combination.

[0040] The alkylphenone compound is not particularly limited. For example, the alkylphenone compound may be 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, etc.

[0041] The benzophenone-based compound is not particularly limited, and examples thereof include benzophenone, 4,4'-bis(dimethylamino)benzophenone, and 2-carboxybenzophenone.

[0042] The benzoin-based compound is not particularly limited, and examples thereof include benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

[0043] The thioxanthone compound is not particularly limited, and examples thereof include thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, and 2,4-diethylthioxanthone.

[0044] The halomethylated triazine compound is not particularly limited. Examples of the halomethylated triazine compound include 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-sec-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-sec-triazine, 2-(4-ethoxynaphthyl)-4,6-bis(trichloromethyl)-sec-triazine, and 2-(4-ethoxycarboxynylnaphthyl)-4,6-bis(trichloromethyl)-sec-triazine.

[0045] The halomethylated oxadiazole compound is not particularly limited. Examples of the halomethylated oxadiazole compound include 2-trichloromethyl-5-[β-(2'-benzofuryl)vinyl]-1,3,4-oxadiazole, 2-trichloromethyl-5-[β-(2'-(6"-benzofuryl)vinyl)]-1,3,4-oxadiazole, and 2-trichloromethyl-5-furyl-1,3,4-oxadiazole.

[0046] The biimidazole compound is not particularly limited, and examples thereof include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, and 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole.

[0047] The oxime ester compound is not particularly limited, and examples thereof include 1-[4-(phenylthio)-, 2-(O-benzoyloxime)]-1,2-octanedione and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime)ethanone.

[0048] The titanocene compound is not particularly limited. An example of the titanocene compound is bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium.

[0049] The benzoate ester compound is not particularly limited, and examples thereof include p-dimethylaminobenzoic acid and p-diethylaminobenzoic acid.

[0050] The acridine compound is not particularly limited, and an example of the acridine compound is 9-phenylacridine.

[0051] The content of the photopolymerization initiator is not particularly limited. For example, the content of the photopolymer in the first inkjet ink is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. The content of the photopolymer in the first inkjet ink is preferably 15% by mass or less, and more preferably 12% by mass or less. By ensuring that the content of the photopolymer is within the above range, the first inkjet ink can be appropriately cured by ultraviolet light or the like.

[0052] (1d) Organic solvents The first inkjet ink preferably contains an organic solvent, which allows the first inkjet ink to be easily adjusted to a relatively low viscosity and provides excellent ejection properties from an inkjet head.

[0053] The organic solvent is not particularly limited. Examples of the organic solvent include lactone-based organic solvents, ketone-based organic solvents, glycol ether-based organic solvents, acetate-based organic solvents, and carbonate-based organic solvents. Among these, it is preferable that the organic solvent contains a glycol ether-based organic solvent. Glycol ether-based organic solvents have low viscosity and a relatively high boiling point. Therefore, the first inkjet ink containing such a solvent has improved drying properties and superior ejection stability during inkjet printing.

[0054] Lactone organic solvents include γ-butyrolactone, γ-valerolactone, δ-valerolactone, etc. Ketone organic solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl isoamyl ketone, diisobutyl ketone, methyl hexyl ketone, isophorone, etc.

[0055] Glycol ether organic solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono(iso)propyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and triethylene glycol monomethyl ether. glycol mono-n-propyl ether, triethylene glycol mono-n-butyl ether, tripropylene glycol monoethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol butyl methyl ether, triethylene glycol butyl methyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, and the like.

[0056] Acetate-based organic solvents include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol mono-n-butyl ether acetate, ethylene glycol mono-sec-butyl ether acetate, ethylene glycol monoisobutyl ether acetate, ethylene glycol mono-tert-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monoisopropyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol mono-n-butyl ether acetate, and propylene glycol mono-sec-butyl ether acetate. alkylene glycol monoalkyl ether acetates such as propylene glycol monoisobutyl ether acetate, propylene glycol mono-tert-butyl ether acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-ethoxybutyl acetate, 3-methyl-3-propoxybutyl acetate, 3-methyl-3-isopropoxybutyl acetate, 3-methyl-3-n-butoxyethyl acetate, 3-methyl-3-isobutoxybutyl acetate, 3-methyl-3-sec-butoxybutyl acetate, and 3-methyl-3-tert-butoxybutyl acetate; ethylene glycol diacetate, diethylene glycol diacetate, triethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol diacetate, and tripropylene glycol diacetate.

[0057] Among the above organic solvents, the organic solvent preferably contains a glycol ether-based organic solvent having a boiling point of 150 to 250°C, and more preferably a glycol ether-based organic solvent having a boiling point of 170 to 220°C. When the boiling point is within the above range, the first inkjet ink has improved drying properties and superior ejection stability during inkjet printing. Furthermore, by using a first inkjet ink containing such an organic solvent, it is easy to obtain clear prints with little bleeding. Furthermore, the resulting ink set makes it easy to produce prints in which the protective layer is more easily peeled off during water transfer.

[0058] When an organic solvent is blended, the content of the organic solvent is not particularly limited. For example, the content of the organic solvent in the first inkjet ink is preferably 0.1% by mass or more, and more preferably 1% by mass or more. Furthermore, the content of the organic solvent in the first inkjet ink is preferably 70% by mass or less, and more preferably 60% by mass or less. By having the content of the organic solvent within the above range, the first inkjet ink is less likely to lose its curability when cured with ultraviolet light, has an appropriate viscosity, and exhibits excellent ejection stability during inkjet printing.

[0059] ·Optional ingredients In addition to the above components, the first inkjet ink of this embodiment may contain optional components well known in the field of inkjet inks, such as a curing catalyst, a dispersant, a slip agent (leveling agent), a dispersant, a polymerization accelerator, a polymerization inhibitor, a penetration accelerator, a humectant (moisturizing agent), a fixing agent, an antifungal agent, a preservative, an antioxidant, a chelating agent, and a thickener.

[0060] The curing catalyst is not particularly limited. Examples of the curing catalyst include organic acid salts, alcoholates, and chelate compounds of metals such as tin, titanium, zirconium, iron, antimony, bismuth, manganese, zinc, and aluminum; amines such as hexylamine and dodecylamine; amine salts such as hexylamine acetate and dodecylamine phosphate; quaternary ammonium salts such as benzyltrimethylammonium acetate; and alkali metal salts such as potassium acetate. More specifically, the curing catalyst includes organic bismuth compounds such as bismuth octoate and bismuth neodecanoate; organic tin compounds such as dibutyltin dilaurate, dibutyltin dioctoate, dimethyltin dineodecanoate, and stannous octoate; and organic titanium compounds such as tetrabutyl titanate, tetraisopropyl titanate, diisopropoxybis(acetylacetone)titanium, and diisopropoxybis(ethylacetoacetate)titanium. The curing catalysts may be used in combination. In this embodiment, the curing catalyst is preferably a tin-based compound, more preferably a dialkyltin-based compound such as dibutyltin dilaurate or dimethyltin dineodecanoate, and even more preferably dibutyltin dilaurate. When dibutyltin dilaurate is contained as the curing catalyst, the first ink-jet ink has better curability.

[0061] When a curing catalyst is blended, the content of the curing catalyst is not particularly limited. For example, the content of the curing catalyst in the first inkjet ink is preferably 0.001% by mass or more, and more preferably 0.005% by mass or more. Furthermore, the content of the curing catalyst in the first inkjet ink is preferably 5% by mass or less, and more preferably 3% by mass or less. By having the content of the curing catalyst within the above range, the curing properties of the first inkjet ink are likely to be improved.

[0062] Polymerization inhibitor A polymerization inhibitor may be suitably added to prevent the polymerization reaction of the first ink-jet ink before curing.

[0063] The polymerization inhibitor is not particularly limited. Examples of the polymerization inhibitor include methylhydroquinone, t-butylhydroquinone, 4-methoxynaphthol, 1,4-benzoquinone, methoquinone, dibutylhydroxytoluene, N-nitrosophenylhydroxylamine aluminum salt, 1,4-naphthoquinone, and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (4-hydroxyTEMPO).

[0064] Returning to the description of the first inkjet ink as a whole, there are no particular limitations on the viscosity of the first inkjet ink. For example, the viscosity of the first inkjet ink is preferably 3 mPa·s or more, and more preferably 5 mPa·s or more, at 35°C. Furthermore, the viscosity of the first inkjet ink is preferably 30 mPa·s or less, and more preferably 20 mPa·s or less, at 35°C. When the viscosity is within the above range, the first inkjet ink has a sufficiently low viscosity, is easy to handle, and exhibits excellent ejection stability during inkjet printing. In this embodiment, the viscosity can be measured using a Brookfield viscometer (TVB-20LT, manufactured by Toki Sangyo Co., Ltd.).

[0065] The method for adjusting the viscosity to within the above range is not particularly limited. For example, the viscosity can be adjusted by the amount and type of each component used. The viscosity may also be adjusted using a viscosity adjuster such as a thickener, if necessary.

[0066] The surface tension of the first inkjet ink is not particularly limited. The surface tension of the first inkjet ink is preferably 20 mN / m or more, more preferably 25 mN / m or more, at 25°C. The surface tension of the first inkjet ink is preferably 40 mN / m or less, more preferably 35 mN / m or less, at 25°C. When the surface tension is within the above range, the first inkjet ink has excellent ejection stability. Furthermore, the first inkjet ink has excellent wettability to the substrate, and the resulting print has excellent adhesion. In this embodiment, the surface tension can be measured using a static surface tensiometer (plate method) (CBVP-A3, manufactured by Kyowa Interface Science Co., Ltd.).

[0067] The method for adjusting the surface tension to within the above range is not particularly limited. For example, the surface tension may be adjusted by adjusting the content of an alicyclic monofunctional (meth)acrylate monomer having a surface tension of 20 to 30 mN / m and a terminal hydroxyl group-containing monofunctional (meth)acrylate monomer having a surface tension of 40 to 60 mN / m, or by adding an acrylic surface conditioner, a silicone surface conditioner, a fluorine surface conditioner, or the like.

[0068] The method for preparing the first inkjet ink of this embodiment is not particularly limited. As an example, the first inkjet ink can be prepared by mixing the materials to be used, dispersing the mixture using a disperser such as a roll mill, a ball mill, a colloid mill, a jet mill, or a bead mill, and then filtering the mixture.

[0069] (Second inkjet ink) The second inkjet ink is an ink for forming a design layer formed on the hiding layer, and includes (2a) a color pigment, (2b) at least one of a difunctional or higher functional (meth)acrylate monomer or a difunctional or higher functional (meth)acrylate oligomer, (2c) a photopolymerization initiator, and (2e) a surface conditioner.

[0070] (2a) Color pigments The second inkjet ink comprises a (2a) color pigment, which is similar to the (1a) color pigment described in relation to the first inkjet ink.

[0071] One or more color pigments are selected depending on the color of the desired design layer. One or more second inkjet inks are prepared depending on the respective colors. For example, master batches containing yellow pigment, red pigment, blue pigment, black pigment, etc. may be prepared as the second inkjet inks constituting the design layer. The prepared master batches are mixed with components (2b) and (2c), etc., described below, to form the second inkjet ink.

[0072] (2b) At least one of a di- or higher functional (meth)acrylate monomer or a di- or higher functional (meth)acrylate oligomer The second inkjet ink contains (2b) at least one of a difunctional or higher functional (meth)acrylate monomer and a difunctional or higher functional (meth)acrylate oligomer. The (2b) at least one of a difunctional or higher functional (meth)acrylate monomer and a difunctional or higher functional (meth)acrylate oligomer is the same as the (1b) at least one of a difunctional or higher functional (meth)acrylate monomer and a difunctional or higher functional (meth)acrylate oligomer described in relation to the first inkjet ink.

[0073] In the second inkjet ink of this embodiment, the total content of the difunctional or higher (meth)acrylate monomer and the difunctional or higher (meth)acrylate oligomer is preferably 60% by mass or more, and more preferably 70% by mass or more, of the total resin components. When the total content is within the above range, the resulting design layer has better UV curability. Therefore, the design layer is less likely to bleed color even when simultaneously printed. Furthermore, the design layer has better solvent resistance to organic solvents in the protective layer. Therefore, the ink set of this embodiment makes it easier to produce printed materials in which the protective layer is more easily peeled off during water transfer.

[0074] (2c) Photopolymerization initiator The second ink-jet ink contains (2c) a photopolymerization initiator, which is the same as (1c) the photopolymerization initiator described in relation to the first ink-jet ink.

[0075] (2d) Organic solvents The second inkjet ink preferably contains (2d) an organic solvent. The (2d) organic solvent is the same as the (1d) organic solvent described in relation to the first inkjet ink. This prevents the resin or pigment in the ink from aggregating due to the different solvent, and even head clogging, even if the spray of ink droplets ejected from an inkjet head adheres to the surface of another head during inkjet printing.

[0076] The organic solvent preferably contains a glycol ether-based organic solvent, more preferably a glycol ether-based organic solvent having a boiling point of 150 to 250°C. Glycol ether-based organic solvents have low viscosity and relatively high boiling points. Therefore, a first inkjet ink containing such a solvent has improved drying properties and superior ejection stability during inkjet printing. Furthermore, when the boiling point is within the above range, the second inkjet ink has improved drying properties and superior ejection stability during inkjet printing. Furthermore, the use of a second inkjet ink containing such an organic solvent makes it easier to obtain clear prints with minimal bleeding. Furthermore, the resulting ink set makes it easier to produce prints in which the protective layer is more easily peeled off during water transfer.

[0077] (2e) Surface conditioner The second inkjet ink contains a surface conditioner. The surface conditioner is not particularly limited. Examples of the surface conditioner include a fluorine-based surface conditioner and a silicone-based surface conditioner. Among these, it is preferable that the surface conditioner contains a fluorine-based surface conditioner.

[0078] The fluorine-based surface conditioner is not particularly limited. Examples thereof include perfluoroalkyl sulfonates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl trimethyl ammonium salts, perfluoroalkyl amino sulfonates, perfluoroalkyl group-hydrophilic group-containing oligomers, perfluoroalkyl group-lipophilic group-containing oligomers, perfluoroalkyl group-(hydrophilic group and lipophilic group)-containing oligomers, perfluoroalkyl group-lipophilic group-containing urethanes, perfluoroalkyl phosphate esters, perfluoroalkyl carboxylates, perfluoroalkyl amine compounds, perfluoroalkyl quaternary ammonium salts, perfluoroalkyl betaines, non-dissociative perfluoroalkyl compounds, and block copolymers having a fluorine-based segment and a (meth)acrylic segment.

[0079] The silicone surface conditioner is not particularly limited, and examples thereof include polyether-modified polydimethylsiloxane, silicone-modified (meth)acrylic polymers having hydroxyl groups, and block copolymers having silicone segments and (meth)acrylic segments.

[0080] The second inkjet ink of this embodiment contains a surface conditioner (2e), and the surface tensions of the first inkjet ink (S1), the second inkjet ink (S2), and the third inkjet ink (S3) are adjusted to satisfy the relationship S1 > S2 > S3. This results in a printed product with higher resolution and less color bleeding. In this embodiment, when multiple second inkjet inks are used (for example, when second inkjet inks containing different color pigments are prepared), the surface tensions of the multiple second inkjet inks may be the same or different. Furthermore, it is preferable that the surface tensions of all of the multiple second inkjet inks be adjusted to satisfy the relationship S1 > S2 > S3.

[0081] Specifically, the surface tension (S1) of the first inkjet ink at 25°C can be adjusted to 27 to 35 (dyne / cm), the surface tension (S2) of the second inkjet ink to 23 to 25 (dyne / cm), and the surface tension (S3) of the third inkjet ink to 19 to 23 (dyne / cm) (where S1>S2>S3).

[0082] When a surface conditioner is contained, the content of the surface conditioner is not particularly limited. For example, the content of the surface conditioner in the second inkjet ink is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more. Furthermore, the content of the surface conditioner in the second inkjet ink is preferably 2% by mass or less, and more preferably 1% by mass or less. When the content of the surface conditioner is within the above range, the second inkjet ink is less likely to cause color bleeding, and high-resolution water transfer inkjet prints can be easily produced.

[0083] ·Optional ingredients In addition to the above components, the second inkjet ink of this embodiment may also contain optional components well known in the art of inkjet inks, as appropriate, which are the same as those described above in relation to the first inkjet ink.

[0084] Returning to the description of the second inkjet ink as a whole, there are no particular limitations on the viscosity of the second inkjet ink. For example, the viscosity of the second inkjet ink is preferably 3 mPa·s or more, and more preferably 5 mPa·s or more, at 35°C. Furthermore, the viscosity of the second inkjet ink is preferably 30 mPa·s or less, and more preferably 20 mPa·s or less, at 35°C. When the viscosity is within the above range, the second inkjet ink has a sufficiently low viscosity, is easy to handle, and exhibits excellent ejection stability during inkjet printing. In this embodiment, the viscosity can be measured using a Brookfield viscometer (TVB-20LT, manufactured by Toki Sangyo Co., Ltd.).

[0085] The method for adjusting the viscosity to within the above range is not particularly limited. For example, the viscosity can be adjusted by the amount and type of each component used. The viscosity may also be adjusted using a viscosity adjuster such as a thickener, if necessary.

[0086] The surface tension of the second inkjet ink is not particularly limited. The surface tension of the second inkjet ink is preferably 20 mN / m or more, more preferably 25 mN / m or more, at 25°C. The surface tension of the second inkjet ink is preferably 40 mN / m or less, more preferably 35 mN / m or less, at 25°C. When the surface tension is within the above range, the second inkjet ink has excellent ejection stability. Furthermore, the second inkjet ink has excellent wettability to the substrate, and the resulting print has excellent adhesion. In this embodiment, the surface tension can be measured using a static surface tensiometer (plate method) (CBVP-A3, manufactured by Kyowa Interface Science Co., Ltd.).

[0087] The method for preparing the second inkjet ink of this embodiment is not particularly limited. As an example, the second inkjet ink can be prepared by mixing the materials to be used, dispersing the mixture using a disperser such as a roll mill, a ball mill, a colloid mill, a jet mill, or a bead mill, and then filtering the mixture.

[0088] (Third inkjet ink) The third inkjet ink is an ink for forming a protective layer on the design layer. When the design layer is provided on a portion of the concealing layer, the protective layer is formed so as to cover both the concealing layer and the design layer. The third inkjet ink contains (3a) an acrylic resin polymer having a glass transition temperature (Tg) of 20 to 50°C, (3b) a fluorine-based surface conditioner, and (3c) an organic solvent.

[0089] (3a) Acrylic resin polymer having a glass transition temperature (Tg) of 20 to 50°C The acrylic resin polymer having a Tg of 20 to 50°C is not particularly limited. For example, the acrylic resin polymer is a polymer or copolymer thereof made of (3c) organic solvent-soluble (meth)acrylate, which will be described later. The (meth)acrylate is an alkyl (meth)acrylate such as ethyl, propyl, or butyl (meth)acrylate; or a hydroxyalkyl (meth)acrylate such as hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, or hydroxypentyl (meth)acrylate.

[0090] The Tg of the acrylic resin polymer may be 20°C or higher, and preferably 25°C or higher. The Tg of the acrylic resin polymer may be 50°C or lower, and preferably 45°C or lower. If the Tg is lower than 20°C, the inkjet film of the third inkjet ink is likely to become tacky and is too soft, making it difficult to handle during water transfer. If the Tg is higher than 50°C, the inkjet film of the third inkjet ink is likely to become hard, causing the film to crack during water transfer.

[0091] The content of the acrylic resin polymer having a Tg of 20 to 50°C is not particularly limited. For example, the content of the acrylic resin polymer having a Tg of 20 to 50°C in the third inkjet ink is preferably 1% by mass or more, and more preferably 5% by mass or more. Furthermore, the content of the acrylic resin polymer having a Tg of 20 to 50°C in the third inkjet ink is preferably 20% by mass or less, and more preferably 10% by mass or less. By ensuring that the content of the acrylic resin polymer having a Tg of 20 to 50°C is within the above range, the third inkjet ink can be easily adjusted to a viscosity suitable for inkjet printing while increasing the resin solids content.

[0092] The third inkjet ink may contain resins other than the acrylic resins described above, provided that the inkjet performance is not impaired. Examples of such resins include vinyl chloride resins, vinyl chloride-vinyl acetate resins, ethylene-vinyl acetate resins, styrene-acrylic resins, styrene-maleic acid resins, rosin resins, rosin ester resins, petroleum resins, coumarone-indene resins, terpene phenol resins, phenol resins, ketone resins, urethane resins, melamine resins, urea resins, epoxy resins, cellulose resins, xylene resins, alkyd resins, aliphatic hydrocarbon resins, butyral resins, maleic acid resins, and fumaric acid resins.

[0093] (3b) Fluorine-based surface conditioners The fluorine-based surface conditioner is not particularly limited. Examples thereof include perfluoroalkyl sulfonates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl trimethyl ammonium salts, perfluoroalkyl amino sulfonates, perfluoroalkyl group-hydrophilic group-containing oligomers, perfluoroalkyl group-lipophilic group-containing oligomers, perfluoroalkyl group-(hydrophilic group and lipophilic group)-containing oligomers, perfluoroalkyl group-lipophilic group-containing urethanes, perfluoroalkyl phosphate esters, perfluoroalkyl carboxylates, perfluoroalkyl amine compounds, perfluoroalkyl quaternary ammonium salts, perfluoroalkyl betaines, non-dissociative perfluoroalkyl compounds, and block copolymers having a fluorine-based segment and a (meth)acrylic segment.

[0094] The content of the fluorine-based surface conditioner is not particularly limited. For example, the content of the fluorine-based surface conditioner in the third inkjet ink is preferably 1% by mass or more, and more preferably 2% by mass or more. Furthermore, the content of the fluorine-based surface conditioner in the third inkjet ink is preferably 5% by mass or less, and more preferably 4% by mass or less. When the content of the fluorine-based surface conditioner is within the above range, the third inkjet ink is less likely to cause color bleeding, and high-resolution water transfer inkjet prints can be easily produced.

[0095] (3c) Organic solvents The third ink-jet ink contains (3c) an organic solvent. The type of (3c) organic solvent is the same as the (1d) organic solvent described in relation to the first ink-jet ink.

[0096] The organic solvent preferably contains a glycol ether-based organic solvent, and more preferably contains a glycol ether-based organic solvent having a boiling point of 150 to 250°C. Glycol ether-based organic solvents have low viscosity and relatively high boiling points. Therefore, third inkjet inks containing these as solvents have improved drying properties and superior ejection stability during inkjet printing. Furthermore, when the boiling point is within the above range, the third inkjet ink has improved drying properties and superior ejection stability during inkjet printing. Furthermore, use of a third inkjet ink containing such an organic solvent makes it easier to obtain clear prints with minimal bleeding. Furthermore, the resulting ink set makes it easier to produce prints in which the protective layer is more easily peeled off during water transfer.

[0097] The content of the organic solvent is not particularly limited. For example, the organic solvent is preferably 80% by mass or more, and more preferably 85% by mass or more, in the third inkjet ink. Furthermore, the organic solvent is preferably 99% by mass or less, and more preferably 95% by mass or less, in the third inkjet ink. When the content of the organic solvent is within the above range, the third inkjet ink has an appropriate viscosity and excellent ejection stability during inkjet printing.

[0098] ·Optional ingredients In addition to the above components, the third inkjet ink of this embodiment may also contain optional components well known in the art of inkjet inks, as appropriate, and the optional components are the same as those described above in relation to the first inkjet ink.

[0099] The third inkjet ink may also contain a plasticizer as an optional component. The plasticizer is not particularly limited. Examples of the plasticizer include fatty acid esters, epoxy compounds, and polyester compounds.

[0100] When a plasticizer is blended, the content of the plasticizer is not particularly limited. For example, the content of the plasticizer in the third inkjet ink is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more. Furthermore, the content of the plasticizer in the third inkjet ink is preferably 10% by mass or less, and more preferably 5% by mass or less. By ensuring that the content of the plasticizer is within the above range, the third inkjet ink can adjust the firmness and stiffness of the inkjet film as desired.

[0101] Returning to the description of the third inkjet ink as a whole, there are no particular limitations on the viscosity of the third inkjet ink. For example, the viscosity of the third inkjet ink is preferably 3 mPa·s or more, and more preferably 5 mPa·s or more, at 35°C. Furthermore, the viscosity of the third inkjet ink is preferably 30 mPa·s or less, and more preferably 20 mPa·s or less, at 35°C. When the viscosity is within the above range, the third inkjet ink has a sufficiently low viscosity, is easy to handle, and exhibits excellent ejection stability during inkjet printing. In this embodiment, the viscosity can be measured using a Brookfield viscometer (TVB-20LT, manufactured by Toki Sangyo Co., Ltd.).

[0102] The method for adjusting the viscosity to within the above range is not particularly limited. For example, the viscosity can be adjusted by the amount and type of each component used. The viscosity may also be adjusted using a viscosity adjuster such as a thickener, if necessary.

[0103] The surface tension of the third inkjet ink is not particularly limited. The surface tension of the third inkjet ink is preferably 20 mN / m or more, more preferably 25 mN / m or more, at 25°C. The surface tension of the third inkjet ink is preferably 40 mN / m or less, more preferably 35 mN / m or less, at 25°C. When the surface tension is within the above range, the third inkjet ink has excellent ejection stability. Furthermore, the third inkjet ink has excellent wettability to the substrate, and the resulting print has excellent adhesion. In this embodiment, the surface tension can be measured using a static surface tensiometer (plate method) (CBVP-A3, manufactured by Kyowa Interface Science Co., Ltd.).

[0104] The method for preparing the third inkjet ink of this embodiment is not particularly limited. As an example, the third inkjet ink can be prepared by mixing the materials to be used, dispersing the mixture using a disperser such as a roll mill, a ball mill, a colloid mill, a jet mill, or a bead mill, and then filtering the mixture.

[0105] As described above, the inkjet ink set of this embodiment provides a print in which the concealing layer and design layer have excellent solvent resistance to the organic solvent in the protective layer. Therefore, the ink set facilitates the production of a print in which the protective layer is easily peeled off during water transfer printing. Furthermore, the design layer has excellent UV curing properties. Therefore, the design layer is less likely to bleed color even when simultaneously printed. Furthermore, the protective layer exhibits excellent peelability and also exhibits appropriate elongation, firmness, and stiffness. Therefore, the print in question is easy to handle during water transfer printing.

[0106] <Method of manufacturing an inkjet print for water transfer and an inkjet print for water transfer> A method for producing a water-transfer inkjet printed material (hereinafter also referred to as a method for producing a printed material) according to one embodiment of the present invention is a method for producing a water-transfer inkjet printed material (hereinafter also referred to as a method for producing a printed material) using the ink set described above. The method for producing a printed material includes a first printing step for forming a concealing layer and a design layer, and a second printing step for forming a protective layer. The first printing step includes: (1-1) applying a first inkjet ink to a substrate coated with a water-soluble resin; (1-2) irradiating the applied first inkjet ink with ultraviolet light to cure it, thereby forming a concealing layer; (1-3) applying a second inkjet ink to the concealing layer; and (1-4) irradiating the applied second inkjet ink with ultraviolet light to cure it, thereby forming a design layer. The second printing step includes: (2-1) applying a third inkjet ink to the design layer; and (2-2) drying and removing the organic solvent from the applied third inkjet ink, thereby forming a protective layer. Each of these will be explained below.

[0107] (1st printing process) The first printing step includes (1-1) applying a first inkjet ink onto a substrate coated with a water-soluble resin.

[0108] The substrate coated with the water-soluble resin is not particularly limited. For example, the substrate coated with the water-soluble resin is a substrate generally used for water transfer printing. For example, the substrate coated with the water-soluble resin is a substrate in which a water-soluble resin such as starch is coated on paper. The paper is preferably high-quality paper, coated paper, or the like. The thickness of the coated water-soluble resin is about 1 to 10 μm.

[0109] The inkjet recording method for applying the first inkjet ink to the substrate is not particularly limited, and examples of such methods include continuous methods such as a charge modulation method, a microdot method, a charge spray control method, and an ink mist method, and on-demand methods such as a piezo method, a pulse jet method, a bubble jet (registered trademark) method, and an electrostatic suction method.

[0110] The amount of the first inkjet ink to be applied is not particularly limited. For example, the amount of ink to be applied is 10 g / m 2 It is preferable that the weight is 20 g / m or more. 2 It is more preferable that the amount of ink applied is 100 g / m or more. 2 Preferably, it is 90 g / m or less. 2 More preferably, it is:

[0111] Next, (1-2) the step of irradiating the applied first inkjet ink with ultraviolet light to cure it and form a concealing layer is carried out.

[0112] The curing conditions for the first inkjet ink are not particularly limited. For example, the UV irradiation intensity is 50 mW / cm. 2 It is preferable that the power is 100 mW / cm or more. 2 It is more preferable that the UV irradiation intensity is 2000 mW / cm or more. 2Preferably, it is 1000 mW / cm or less. 2 When the UV irradiation intensity is within the above range, the hiding layer can be appropriately cured.

[0113] The UV irradiation energy (integral light amount) is not particularly limited. For example, the integrated light amount is 50 mJ / cm 2 It is preferable that the concentration is 100 mJ / cm or more. 2 It is more preferable that the cumulative light amount is 3000 mJ / cm or more. 2 Preferably, it is 2000 mJ / cm or less. 2 When the integrated amount of light is within the above range, the hiding layer can be appropriately cured.

[0114] The thickness of the cured concealing layer is not particularly limited. For example, the thickness of the concealing layer is preferably 5 μm or more, more preferably 10 μm or more. Furthermore, the thickness of the concealing layer is preferably 60 μm or less, more preferably 50 μm or less. When the thickness of the concealing layer is within the above range, the inkjet film of the printed matter does not become too thick, and appropriate concealing properties can be imparted.

[0115] Next, (1-3) the step of applying a second inkjet ink onto the hiding layer is carried out.

[0116] The inkjet recording method for applying the second inkjet ink onto the hiding layer is not particularly limited, and examples of such methods include continuous methods such as a charge modulation method, a microdot method, a charge spray control method, and an ink mist method, and on-demand methods such as a piezo method, a pulse jet method, a bubble jet (registered trademark) method, and an electrostatic suction method.

[0117] The amount of the second inkjet ink to be applied is not particularly limited. For example, the amount of ink to be applied is 0.01 g / m 2 relative to the masking layer. 2 It is preferable that the content is 0.1 g / m or more. 2It is more preferable that the amount of ink applied is 30 g / m or more. 2 Preferably, it is 20 g / m or less. 2 More preferably, it is:

[0118] Next, (1-4) the step of irradiating the applied second inkjet ink with ultraviolet light to cure it and form a design layer is carried out.

[0119] The curing conditions for the second inkjet ink are not particularly limited. For example, the UV irradiation intensity is 50 mW / cm. 2 It is preferable that the power is 100 mW / cm or more. 2 It is more preferable that the UV irradiation intensity is 2000 mW / cm or more. 2 Preferably, it is 1000 mW / cm or less. 2 It is more preferable that the UV irradiation intensity is within the above range, so that the design layer can be appropriately cured.

[0120] The UV irradiation energy (integral light amount) is not particularly limited. For example, the integrated light amount is 50 mJ / cm 2 Preferably, it is 100 mJ / cm or more. 2 It is more preferable that the cumulative light amount is 3000 mJ / cm or more. 2 Preferably, it is 2000 mJ / cm or less. 2 When the integrated light amount is within the above range, the design layer can be appropriately cured.

[0121] The thickness of the cured design layer is not particularly limited. For example, the thickness of the design layer is preferably 0.01 μm or more, and more preferably 0.1 μm or more. The thickness of the design layer is preferably 30 μm or less, and more preferably 20 μm or less. By keeping the thickness of the design layer within the above range, the printed matter does not require an inkjet film that is too thick, making it easy to express the desired image.

[0122] In this embodiment, when a multi-color design is to be formed as the design layer, masterbatches containing the respective color materials are prepared as the second inkjet ink. Each masterbatch is individually ejected from the head of the inkjet recording device to form the desired design. In this embodiment, the second inkjet ink can be instantly cured by ultraviolet light. Therefore, the inks containing the respective color materials do not bleed into each other.

[0123] In this embodiment, the above-described steps (1-1) to (1-4) are performed substantially simultaneously as a series of steps. That is, the inkjet recording device is a serial printer, with a first row of heads for printing the concealing layer, followed by a second row of heads for printing the design layer, arranged in order from the substrate transport entrance, and an ultraviolet irradiation device installed next to the heads. Steps (1-1) to (1-4) are performed consecutively so that they are substantially simultaneous. This results in higher manufacturing efficiency than when using conventional solvent-based inks, which require drying after each application of each colorant. Furthermore, even without the need for drying after each application, the first printing step of this embodiment is less likely to cause bleeding in the resulting design.

[0124] (2nd printing process) The second printing step includes (2-1) applying a third inkjet ink onto the design layer.

[0125] The method for applying the third inkjet ink onto the design layer by inkjet recording is not particularly limited, and examples of such methods include continuous methods such as a charge modulation method, a microdot method, a charge spray control method, and an ink mist method, and on-demand methods such as a piezo method, a pulse jet method, a bubble jet (registered trademark) method, and an electrostatic suction method.

[0126] The amount of the third inkjet ink applied is not particularly limited. For example, the amount of ink applied is 50 g / m 2 for the design layer. 2 It is preferable that the content is 100 g / m or more. 2It is more preferable that the amount of ink applied is 300 g / m or more. 2 Preferably, it is 250 g / m or less. 2 More preferably, it is:

[0127] Next, (2-2) the step of drying and removing the organic solvent from the applied third inkjet ink to form a protective layer is carried out.

[0128] The drying conditions are not particularly limited, but an example is drying in an oven at 150°C for 3 minutes.

[0129] The thickness of the dried protective layer is not particularly limited. For example, the thickness of the protective layer is preferably 10 μm or more, more preferably 15 μm or more. The thickness of the protective layer is preferably 40 μm or less, more preferably 30 μm or less. When the thickness of the protective layer is within the above range, the printed matter has an appropriate thickness and is easy to handle during water transfer.

[0130] Through the above steps, an inkjet print for water transfer is produced. The inkjet print for water transfer of this embodiment is an inkjet print for water transfer, in which a water transfer paper is formed on a substrate coated with a water-soluble resin, and the water transfer paper has a concealing layer, a design layer formed on the concealing layer, and a protective layer formed on the design layer laminated thereon. When the design layer is provided on a portion of the concealing layer, the protective layer is formed so as to cover the concealing layer and the design layer. The concealing layer, the design layer, and the protective layer are layers to which the first inkjet ink, the second inkjet ink, and the third inkjet ink of the inkjet ink set described above are applied, respectively.

[0131] In the printed matter of this embodiment, the concealing layer and the design layer have excellent solvent resistance to the organic solvent in the protective layer. Therefore, the protective layer of the printed matter is easily peeled off during water transfer. Furthermore, the design layer has excellent UV curing properties. Therefore, the design layer is less likely to bleed colors even when simultaneously printed. Furthermore, the protective layer exhibits excellent peelability and moderate stretch, firmness, and stiffness. Therefore, the printed matter is easy to handle during water transfer.

[0132] More specifically, when water transfer is performed on the resulting print, the substrate is first removed. That is, by submerging the print in water, part of the substrate (for example, the starch layer) dissolves, and the water transfer paper (printed film) floats on the water. The floating printed film is then scooped up by another substrate to which it is to be transferred. Any water or air that has entered between the substrate and the printed film is pushed out as appropriate. The wetted substrate is then thermally dried. This solidifies the starch that was wet with water, and the printed film adheres to the substrate. Next, the protective layer is peeled off, and a top coat is applied to cover the print to improve adhesion and add hardness. [Example]

[0133] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0134] The raw materials used are shown below. (color pigments) Each colorant was dispersed in the following formulation to prepare a master batch. W Masterbatch Color pigment 1 50.0 parts by mass Dispersant 1 6.2 parts by mass Solvent 1 43.8 parts by mass Total 100.0 parts by mass Color pigment 1: Titanium oxide white pigment, Typaque PFC107, manufactured by Ishihara Sangyo Kaisha, Ltd. Dispersant 1: SOLSPERSE 33000, manufactured by Lubrizol Solvent 1: DEDG (diethylene glycol diethyl ether), manufactured by Nippon Nyukazai Co., Ltd. ·K Masterbatch Color pigment 2 15.0 parts by mass Dispersant 2 8.0 parts by mass Solvent 2 77.0 parts by mass Total 100.0 parts by mass Color pigment 2: Carbon-based (carbon black) black pigment, NIPEX35, manufactured by Orion Engineered Carbons Co., Ltd. Dispersant 2: SOLSPERSE 33000, manufactured by Lubrizol Solvent 2: DEDG (diethylene glycol diethyl ether), manufactured by Nippon Nyukazai Co., Ltd. M Masterbatch Color pigment 3 15.0 parts by mass Dispersant 3 10.0 parts by mass Solvent 3 75.0 parts by mass Total 100.0 parts by mass Color pigment 3: quinacridone black pigment, Ink Jet Red E5B 02, manufactured by Clariant Japan Co., Ltd. Dispersant 3: SOLSPERSE 32000, manufactured by Lubrizol Solvent 3: DEDG (diethylene glycol diethyl ether), manufactured by Nippon Nyukazai Co., Ltd. (UV-curable oligomer) UV-curable oligomer 1: EBECRYL 8810, manufactured by Daicel Allnex Co., Ltd., bifunctional UV-curable oligomer 2: CN9009, manufactured by Sartomer, bifunctional (UV-curable monomer) UV-curable monomer 1: CN9003, manufactured by Sartomer, bifunctional UV-curable monomer 2: IBXA, manufactured by Osaka Organic Chemical Industry, Ltd., monofunctional (acrylic resin polymer) Acrylic resin polymer 1: BR-117, manufactured by Mitsubishi Chemical Corporation, Tg 34°C Acrylic resin polymer 2: BR-1122, manufactured by Mitsubishi Chemical Corporation, Tg 20°C Acrylic resin polymer 3: BR-116, manufactured by Mitsubishi Chemical Corporation, Tg 48°C Acrylic resin polymer 4: BR-90, manufactured by Mitsubishi Chemical Corporation, Tg 65°C (surface conditioner) Surface conditioner 1: Megafac F-563, manufactured by DIC Corporation, fluorine-based surface conditioner Surface conditioner 2: Megafac F-556, manufactured by DIC Corporation, fluorine-based surface conditioner Surface conditioner 3: BYK-UV 3570, manufactured by BYK Japan Co., Ltd., silicone-based surface conditioner (organic solvent) Organic solvent 1: DEDG, diethylene glycol diethyl ether, glycol ether type, boiling point 189°C Organic solvent 2: DPM, dipropylene glycol methyl ether, glycol ether type, boiling point 188°C (Photopolymerization initiator) Photopolymerization initiator 1: Omnirad 184, manufactured by IGM Resins BV Photopolymerization initiator 2: Omnirad 819, manufactured by IGM Resins BV (others) Plasticizer: Sanso Cizer E-9000H, manufactured by New Japan Chemical Co., Ltd. Polymerization inhibitor: 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl

[0135] Example 1 A first inkjet ink, a second inkjet ink, and a third inkjet ink were prepared according to the formulations (unit: parts by mass) shown in Tables 1 and 2 below. The viscosity and surface tension of each inkjet ink were measured using the following evaluation methods. The first inkjet ink was applied to a substrate (water transfer paper, SPA, manufactured by Marusige Shiko Co., Ltd.) under the following inkjet printing conditions 1 (step (1-1) of the first printing process), and then irradiated with ultraviolet light under the following ultraviolet irradiation conditions 1 to form a concealing layer (thickness: 20 μm) (step (1-2) of the first printing process). Next, the second inkjet ink was applied to the concealing layer under the following inkjet printing conditions 2 (step (1-3) of the first printing process), and then irradiated with ultraviolet light under the following ultraviolet irradiation conditions 2 and dried under the following drying conditions 1 to form a design layer (thickness: 10 μm) (step (1-4) of the first printing process). Furthermore, a third inkjet ink was applied to the design layer under the following inkjet printing condition 3 (step (2-1) of the second printing step), and dried under the following drying condition 1 to form a protective layer (thickness: 20 μm) (step (2-2) of the second printing step). In this way, the water transfer inkjet print of Example 1 was produced. The obtained print was evaluated for printed image design (bleeding), printed image design (streaks), handleability of the transfer film, and peelability of the protective layer using the following evaluation methods. The results are shown in Tables 1 and 2.

[0136] <Examples 2 to 8 and Comparative Examples 1 to 6> Aside from changing the formulation as shown in Tables 1 and 2, water transfer inkjet prints were produced in the same manner as in Example 1. In Example 8, second inkjet inks containing K masterbatch and M masterbatch were prepared and used.

[0137] (viscosity) Measurement was carried out at 50°C using a Brookfield viscometer (TVB-20LT, manufactured by Toki Sangyo Co., Ltd.). (surface tension) The surface tension was measured at 25°C using a static surface tensiometer (CBVP-A3, Kyowa Interface Science Co., Ltd.) by the Wilhelmy method.

[0138] (Inkjet printing condition 1) Nozzle diameter 40μm Voltage 70V Pulse width 10μs Drive frequency 10kHz Resolution: 400 x 800 dpi Application amount: 40g / m 2 (Ultraviolet irradiation condition 1) Lamp type: Metal halide lamp, manufactured by Integration Technology Irradiation intensity (measurement wavelength 365nm) 480mW / cm 2 Accumulated light intensity (measured at 365 nm): 1440 mJ / cm 2 Irradiation height: 45cm (Inkjet printing condition 2) Nozzle diameter 40μm Voltage 70V Pulse width 10μs Drive frequency 10kHz Resolution: 400 x 800 dpi Application amount: 20g / m 2 (Ultraviolet irradiation condition 2) Lamp type: Metal halide lamp, manufactured by Integration Technology Irradiation intensity (measurement wavelength 365nm) 480mW / cm 2 Accumulated light intensity (measured at 365 nm): 1440 mJ / cm 2 Irradiation height: 45cm (Inkjet printing condition 3) Nozzle diameter 40μm Voltage 70V Pulse width 10μs Drive frequency 10kHz Resolution: 400 x 800 dpi Application amount: 200g / m 2 (Drying condition 1) Drying temperature 150℃ Drying time: 1 minute

[0139] <Printed image design (bleeding)> The degree of bleeding was evaluated according to the following evaluation criteria. (Evaluation criteria) ○: The printed ink dots were independent and did not bleed. △: The printed ink dots were slightly blurred. ×: The printed ink dots bled and the colors mixed.

[0140] <Printed image design (streaks)> The degree of streaking was evaluated according to the following evaluation criteria. (Evaluation criteria) ◯: The printed image was clean and free of streaks. ×: The printed image had many streaks and looked pale.

[0141] <Handling of transfer membrane> The state of the transfer film (the ink film after the printed material is floated on water and the substrate is detached as the water-soluble resin layer dissolves) when floated on water was evaluated according to the following evaluation criteria. (Evaluation criteria) ◯: The transfer film did not crack or stick (it became crumpled due to tack), and water transfer was possible. ×: The transfer film cracked or stuck (crumpled due to tack), and water transfer was not possible.

[0142] <Removability of protective layer> The degree of peelability of the protective layer was evaluated according to the following evaluation criteria. (Evaluation criteria) ◯: The protective layer could be peeled off cleanly. △: The protective layer was peelable, but a portion remained on the concealing layer and the design layer. ×: The protective layer could not be peeled off and remained on the concealing layer or the design layer.

[0143] [Table 1]

[0144] [Table 2]

[0145] As shown in Tables 1 and 2, the water transfer inkjet ink sets and water transfer inkjet prints of Examples 1 to 8 of the present invention were produced in a short time, with each layer being formed by inkjet printing and UV curing. Furthermore, the resulting prints were highly precise, with no bleeding or streaks. Furthermore, the resulting prints had transfer films that were easy to handle, and the protective layer was easy to peel off.

Claims

1. An inkjet ink set for water transfer printing for printing water transfer paper, the water transfer paper comprising a substrate coated with a water-soluble resin, a concealing layer, a design layer formed on the concealing layer, and a protective layer formed on the design layer, the water transfer paper comprising: the inkjet ink set includes a first inkjet ink for forming the hiding layer, a second inkjet ink for forming the design layer, and a third inkjet ink for forming the protective layer; the first ink-jet ink contains (1a) a color pigment, (1b) at least one of a di- or higher functional (meth)acrylate monomer or a di- or higher functional (meth)acrylate oligomer, and (1c) a photopolymerization initiator; the second ink-jet ink contains (2a) a color pigment, (2b) at least one of a di- or higher functional (meth)acrylate monomer or a di- or higher functional (meth)acrylate oligomer, (2c) a photopolymerization initiator, and (2e) a surface conditioner; The third ink-jet ink contains (3a) an acrylic resin polymer having a glass transition temperature (Tg) of 20 to 50°C, (3b) a fluorine-containing surface conditioner, and (3c) an organic solvent; a surface tension (S1) of the first inkjet ink, a surface tension (S2) of the second inkjet ink, and a surface tension (S3) of the third inkjet ink satisfy the relationship S1 > S2 > S3.

2. The first ink-jet ink comprises: (1b) a total content of at least one of a di- or higher functional (meth)acrylate monomer and a di- or higher functional (meth)acrylate oligomer of 60% by mass or more of the total resin components; 2. The water transfer inkjet ink set according to claim 1, wherein the second inkjet ink contains (2b) at least one of a di- or higher functional (meth)acrylate monomer and a di- or higher functional (meth)acrylate oligomer in a total content of 60 mass % or more of all resin components.

3. the first inkjet ink contains (1d) an organic solvent; The water transfer inkjet ink set according to claim 1 or 2, wherein the second inkjet ink contains (2d) an organic solvent.

4. (1d) the organic solvent is a glycol ether solvent having a boiling point of 150 to 250°C; The ink-jet ink set for water transfer printing according to claim 3, wherein the organic solvent (2d) is a glycol ether solvent having a boiling point of 150 to 250°C.

5. The water transfer inkjet ink set according to any one of claims 1 to 4, wherein (3c) the organic solvent is a glycol ether solvent having a boiling point of 150 to 250°C.

6. A water transfer inkjet print is formed by laminating a hiding layer, a design layer formed on the hiding layer, and a protective layer formed on the design layer on a substrate coated with a water-soluble resin, and forming a water transfer paper thereon; 6. A water-transfer inkjet printed matter, wherein the concealing layer, the design layer, and the protective layer are layers to which the first inkjet ink, the second inkjet ink, and the third inkjet ink of the inkjet ink set according to any one of claims 1 to 5 are applied, respectively.

Images