Decorative sheet

Abstract

To provide a decorative sheet that can employ various substrates, has excellent brightness, and also has excellent coating properties such as water resistance.SOLUTION: A decorative sheet includes a substrate, a first layer provided on the substrate, and a second layer provided on the first layer, wherein the first layer is endowed with a first ink, the first ink is a UV-curable ink, and the second layer is endowed with a second ink including metal particles.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a decorative sheet. More specifically, this invention relates to a decorative sheet that can use various substrates, has excellent brightness, and has excellent coating film properties such as water resistance. [Background technology]

[0002] Conventionally, metallic decorative sheets using various substrates are known (for example, Patent Document 1). Patent Document 1 discloses an ultraviolet-curable ink containing metal particles. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-179093 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the UV-curable ink described in Patent Document 1 tends to produce varying levels of brightness depending on the type of substrate. Furthermore, the resulting coating film had room for improvement in physical properties such as water resistance.

[0005] This invention was made to solve these problems, and aims to provide a decorative sheet that can be used with various substrates, has excellent brightness, and has excellent coating film properties such as water resistance. [Means for solving the problem]

[0006] The decorative sheet of the present invention, which solves the above problems, mainly includes the following configuration.

[0007] (1) A decorative sheet comprising a substrate, a first layer provided on the substrate, and a second layer provided on the first layer, wherein the first layer is a layer to which a first ink is applied, the first ink is an ultraviolet-curable ink, and the second layer is a layer to which a second ink containing metal particles is applied.

[0008] With this configuration, the first layer improves the ink resistance, solvent resistance, and smoothness of the substrate. Furthermore, the first ink constituting the first layer is an ultraviolet-curable ink, and can constitute a first layer with a large film thickness. Therefore, even when various substrates are used, the surface condition of the substrate is easily made uniform due to the presence of the first layer. As a result, the decorative sheet can use various substrates with different surface conditions, the surface condition can be made uniform for any substrate, and the brightness is easily improved by adding the second layer.

[0009] (2) The decorative sheet according to (1), comprising a third layer provided on the second layer, wherein the third layer is a layer to which a third ink is applied, and the third ink is either a water-based ink or a solvent-based ink.

[0010] With this configuration, the decorative sheet has superior abrasion resistance and water resistance. Furthermore, if a colored ink is used as the third ink, metallic decorative sheets of various colors can be produced.

[0011] (3) The decorative sheet according to (2), wherein the thickness of the third layer is 5 to 100 μm.

[0012] With this configuration, the decorative sheet has superior abrasion resistance and water resistance. Furthermore, if a colored ink is used as the third ink, metallic decorative sheets of various colors can be produced.

[0013] (4) The decorative sheet according to (2) or (3), wherein the third ink comprises a polyurethane resin, a polyester resin, or a polyacrylic resin.

[0014] According to such a configuration, the decorative sheet is less likely to have its texture of the base material impaired.

[0015] (5) The thickness of the first layer is 3 to 50 μm, and the thickness of the second layer is 5 μm or less. The decorative sheet according to any one of (1) to (4).

[0016] According to such a configuration, the surface state of the base material of the decorative sheet is more likely to be made uniform, and excellent brightness can be easily exhibited even when various base materials are used.

[0017] (6) The second ink is an inkjet ink. The decorative sheet according to any one of (1) to (5).

[0018] According to such a configuration, it is easy to form the second layer showing a desired metallic tone on the decorative sheet.

[0019] (7) The first ink is an inkjet ink. The decorative sheet according to any one of (1) to (6).

[0020] According to such a configuration, the first layer is more likely to be diffusely reflected as compared with the case of forming by a method other than an inkjet recording method such as screen printing. As a result, it has a glittery lame-like appearance, and the brightness is more likely to be improved. Also, adjustment of the brightness is facilitated.

[0021] (8) The average particle diameter of the metal particles is 0.2 to 0.5 μm. The decorative sheet according to any one of (1) to (7).

[0022] According to such a configuration, when the second ink constituting the second layer is applied by an inkjet recording method, the ejection property is excellent. Also, the second ink is likely to form a second layer showing excellent brightness.

[0023] (9) In the second layer, the composition ratio of the metal particles to the resin component constituting the second layer is 1:0.025 to 1:10. The decorative sheet according to any one of (1) to (8).

[0024] With this configuration, the second layer exhibits excellent brightness. Furthermore, even when a third layer is formed, the second layer has excellent solvent resistance to the third ink, making it easier to maintain its excellent brightness.

[0025] (10) The decorative sheet according to any one of (1) to (9), wherein the glass transition temperature (Tg) of the resin component constituting the first ink is 25 to 85°C.

[0026] With this configuration, the first ink constituting the first layer has excellent wettability and is easily applied to the substrate. In addition, the flexibility of the first layer can be easily adjusted to match the flexibility of the substrate.

[0027] (11) The decorative sheet according to any one of (1) to (10), wherein the metal particles contain indium.

[0028] With this configuration, the decorative sheet has better water resistance. [Effects of the Invention]

[0029] According to the present invention, various substrates can be used, and a decorative sheet can be provided that has excellent brightness and coating film properties such as water resistance. [Modes for carrying out the invention]

[0030] <Decorative sheet> A decorative sheet according to one embodiment of the present invention comprises a substrate, a first layer provided on the substrate, and a second layer provided on the first layer. The first layer is a layer to which a first ink is applied. The first ink is an ultraviolet-curable ink. The second layer is a layer to which a second ink containing metal particles is applied. Each of these will be described below.

[0031] (base material) The substrate is not particularly limited. For example, the substrate may be a metal plate such as steel plate, aluminum, or stainless steel; a plastic plate or film such as acrylic, polycarbonate (PC), ABS, polypropylene (PP), polyethylene terephthalate (PET), polymethacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS), or vinyl chloride; a ceramic plate; concrete; wood; glass; synthetic leather; artificial leather; natural leather. The substrate may also be a transparent substrate that exhibits light transmission, or a colored substrate. In the case of a transparent substrate, the substrate may be used with the substrate side as the front side or the back side. If the substrate is a film, the film may be a single layer or a multi-layer product. Furthermore, the substrate may be treated to impart various functionalities such as water repellency, flame retardancy, or stain resistance.

[0032] Even when a substrate with an uneven surface, such as synthetic leather, is used in the decorative sheet of this embodiment, the surface condition of the substrate is easily made uniform by providing the first layer described later. As a result, the decorative sheet can use various substrates with different surface conditions, the surface condition can be made uniform for any substrate, and the brightness can be easily improved by applying the second layer.

[0033] The thickness of the substrate is not particularly limited. For example, the thickness of the substrate is preferably 10 μm or more, and more preferably 50 μm or more. Furthermore, the thickness of the substrate is preferably 500 μm or less, and more preferably 400 μm or less. By having the substrate thickness within the above range, the decorative sheet is easy to transport in various recording methods, resulting in good convenience during manufacturing.

[0034] (1st layer) The first layer is a layer provided on the substrate and is formed by applying the first ink to the substrate.

[0035] • First ink The first ink is an ultraviolet-curable ink. The first ink may contain, for example, a reactive monomer, a reactive oligomer, a photopolymerization initiator, a binder resin, a dispersant, a solvent, and various optional components. The first ink may also be a clear ink or a colored ink. If the first ink is a colored ink, it contains a coloring pigment.

[0036] The coloring pigments may be a mixture of various inorganic or organic pigments. Examples of inorganic pigments include oxides, complex oxides, hydroxides, sulfides, ferrocyanides, chromates, carbonates, silicates, phosphates, carbons (carbon black), and metal powders. Examples of organic pigments include nitroso compounds, colored lakes, azo lakes, insoluble azo compounds, monoazo compounds, disazo compounds, condensed azo compounds, benzimidazolone compounds, phthalocyanines, anthraquinones, perylene compounds, quinacridone compounds, dioxazine compounds, isoindolines, azomethines, and pyrrolopyrroles. These may be used in combination.

[0037] In this embodiment, when improving the weather resistance of the decorative sheet, it is preferable to use inorganic pigments as the coloring pigment. Furthermore, from the viewpoint of obtaining excellent color development of the resulting decorative sheet, it is preferable to use organic pigments.

[0038] The coloring pigment may be dispersed in various dispersants. In this embodiment, it is more preferable that the coloring pigment is dispersed in a polymer dispersant, as this results in a more superior water repellency of the resulting decorative sheet.

[0039] The polymeric dispersant is not particularly limited. Examples include polyoxyalkylene, polyalkylene, polyamine, vinyl polymers or copolymers, acrylic polymers or copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, etc. Multiple polymeric dispersants may be used in combination.

[0040] The acid value of the polymeric dispersant is preferably 5 mg KOH / g or higher, and more preferably 15 mg KOH / g or higher. The amine value of the polymeric dispersant is preferably 15 mg KOH / g or higher, and more preferably 25 mg KOH / g or higher. Polymeric dispersants with these acid and amine values ​​exhibit excellent adsorption properties to colored pigments. In this embodiment, the acid value represents the acid value per gram of dispersant solids and can be calculated by potentiometric titration in accordance with JIS K 0070. The amine value represents the amine value per gram of dispersant solids and can be calculated by converting the value obtained by potentiometric titration using a 0.1 mol / L hydrochloric acid aqueous solution to the equivalent amount of potassium hydroxide.

[0041] If a coloring pigment is included, the content of the coloring pigment in the first ink is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more. Furthermore, the content of the coloring pigment in the first ink is preferably 20% by mass or less, and more preferably 10% by mass or less. When the content of the coloring pigment is within the above range, the resulting decorative sheet is more likely to develop color sufficiently.

[0042] Reactive monomers are not particularly limited. For example, reactive monomers include various aromatic vinyl monomers, vinyl ester monomers, vinyl ethers, allyl compounds, (meth)acrylamides, and (meth)acrylates. More specifically, reactive monomers include aromatic vinyl monomers such as styrene, α-methylstyrene, α-chlorostyrene, vinyltoluene, and divinylbenzene; vinyl ester monomers such as vinyl acetate, vinyl butyrate, N-vinylformamide, N-vinylacetamide, N-vinyl-2-pyrrolidone, N-vinylcaprolactam, and divinyl adipate; vinyl ethers such as ethyl vinyl ether and phenyl vinyl ether; allyl compounds such as diallyl phthalate, trimethylolpropanediallyl ether, and allyl glycidyl ether; acrylamide, N,N-dimethylacrylamide, N,(Meth)acrylamides such as N-dimethylmethacrylamide, N-methylolacrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide, Nt-butylacrylamide, acryloylmorpholine, methylenebisacrylamide; (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethyl (meth)acrylate (meth)hexyl, (meth)lauryl acrylate, (meth)stearyl acrylate, (meth)tetrahydrofurfuryl meth)acrylate, (meth)morpholyl meth)acrylate, (meth)2-hydroxyethyl meth)acrylate, (meth)2-hydroxypropyl meth)acrylate, (meth)4-hydroxybutyl meth)acrylate, (meth)glycidyl meth)acrylate, (meth)dimethylaminoethyl meth)acrylate, (meth)diethylaminoethyl meth)acrylate, (meth)benzyl meth)acrylate, (meth)cyclohexyl meth)acrylate, (meth)phenoxyethyl meth)acrylate, (meth) Monofunctional (meth)acrylates such as tricyclodecane acrylic acid, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, allyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, isobornyl (meth)acrylate, methyl acrylic acid (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl acrylate, tetrahydrofurfuryl acrylate, and phenyl (meth)acrylate; and ethylene glycol di(meth)acrylate, di(meth)acrylic acid Diethylene glycol, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate (n=5~14), propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate (n=5~14), 1,3-butylene glycol di(meth)acrylate, 1,4-Butanediol, polybutylene glycol di(meth)acrylate (n=3~16), poly(1-methylbutylene glycol) di(meth)acrylate (n=5~20), 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate ester, dicyclopentanediol di(meth)acrylate, tricyclodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylol Examples include polyfunctional (meth)acrylates such as ropanetrioxyethyl (meth)acrylate, trimethylolpropanetrioxypropyl (meth)acrylate, trimethylolpropanepolyoxyethyl (meth)acrylate, trimethylolpropanepolyoxypropyl (meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate di(meth)acrylate, ethylene oxide-added bisphenol A di(meth)acrylate, ethylene oxide-added bisphenol F di(meth)acrylate, propylene oxide-added bisphenol A di(meth)acrylate, propylene oxide-added bisphenol F di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, bisphenol A epoxy di(meth)acrylate, and bisphenol F epoxy di(meth)acrylate. These reactive monomers may be used in combination. Among these, reactive monomers such as (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl acrylate and tetrahydrofurfuryl acrylate are preferred due to their relatively low viscosity.

[0043] The reactive monomer may be a reactive monomer to which a functional group such as phosphorus, fluorine, ethylene oxide, or propylene oxide has been added.

[0044] When a reactive monomer is incorporated, the amount of the reactive monomer is not particularly limited. For example, the amount of the reactive monomer is preferably 50 parts by mass or more, and more preferably 60 parts by mass or more, per 100 parts by mass of the first ink. Furthermore, the amount of the reactive monomer is preferably 95 parts by mass or less, and more preferably 90 parts by mass or less, per 100 parts by mass of the first ink. When the amount of the reactive monomer is within the above range, the viscosity of the first ink is easily adjusted, and ejection defects are less likely to occur when inkjet printing is performed. In addition, the first ink is easily cured properly.

[0045] The reactive oligomer is not particularly limited. For example, the reactive oligomer may be urethane acrylate, polyester acrylate, epoxy acrylate, silicone acrylate, polybutadiene acrylate, etc. The reactive oligomer may be used in combination. Among these, the reactive oligomer is preferably urethane acrylate due to its excellent toughness, flexibility, and adhesion. The urethane acrylate is not particularly limited. For example, the urethane acrylate is preferably aliphatic urethane acrylate made of hydrocarbons due to its excellent resistance to yellowing. The reactive oligomer may be used in combination with the reactive monomer.

[0046] The weight-average molecular weight (Mw) of the reactive oligomer is not particularly limited. For example, the Mw of the reactive oligomer is preferably 1000 or more, and more preferably 2000 or more. Furthermore, the Mw of the reactive oligomer is preferably 50000 or less, and more preferably 30000 or less. When the molecular weight of the reactive oligomer is within the above range, the viscosity of the first ink can be easily adjusted, and ejection defects are less likely to occur when inkjet printing is performed. In this specification, the Mw of the reactive oligomer is a value measured by GPC (gel permeation chromatography), for example, and can be measured using a high-speed GPC instrument (HLC-8120GPC, manufactured by Tosoh Corporation).

[0047] When a reactive oligomer is incorporated, the amount of the reactive oligomer is not particularly limited. For example, the amount of the reactive oligomer is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more, per 100 parts by mass of the first ink. Furthermore, the amount of the reactive oligomer is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less, per 100 parts by mass of the first ink. When the amount of the reactive oligomer is within the above range, the viscosity of the first ink is easily adjusted, and ejection defects are less likely to occur when inkjet printing is performed. In addition, the first ink easily forms a coating film with excellent coating film properties.

[0048] The photopolymerization initiator is not particularly limited. For example, photopolymerization initiators include benzoins, benzyl ketals, amino ketones, titanocenes, bisimidazoles, hydroxyketones, and acylphosphine oxides. Photopolymerization initiators may be used in combination. Among these, hydroxyketones and acylphosphine oxides are preferred as photopolymerization initiators due to their excellent reactivity and resistance to yellowing.

[0049] When a photopolymerization initiator is included, the amount of the photopolymerization initiator is not particularly limited. For example, the amount of the photopolymerization initiator is preferably 1 part by mass or more, and more preferably 3 parts by mass or more, per 100 parts by mass of the first ink. Furthermore, the amount of the photopolymerization initiator is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the first ink. Polymerization proceeds easily when the amount of the photopolymerization initiator is within the above range.

[0050] Binder resins are preferably included, for example, to adjust the viscosity of the first ink, adjust the hardness of the first layer, or control its shape.

[0051] The type of binder resin is not particularly limited. Examples of binder resins include fluororesins, epoxy resins, diallyl phthalate resins, silicone resins, phenolic resins, unsaturated polyester resins, polyimide resins, polyurethane resins, melamine resins, urea resins, ionomer resins, ethylene ethyl acrylate resins, acrylonitrile acrylate styrene copolymer resins, acrylonitrile styrene resins, acrylonitrile chlorinated polyethylene styrene copolymer resins, ethylene vinyl acetate resins, ethylene vinyl alcohol copolymer resins, acrylonitrile butadiene styrene copolymer resins, vinyl chloride resins, chlorinated polyethylene resins, polyvinylidene chloride resins, cellulose acetate resins, polyoxymethylene resins, and polyamide resins. Examples include polyarylate resin, thermoplastic polyurethane elastomer, polyether ether ketone resin, polyether sulfone resin, polyethylene, polypropylene, polycarbonate resin, polystyrene, polystyrene maleic acid copolymer resin, polystyrene acrylic acid copolymer resin, polyphenylene ether resin, polyphenylene sulfide resin, polybutadiene resin, polybutylene terephthalate resin, acrylic resin, methylpentene resin, polylactic acid, polybutylene succinate resin, butyral resin, formal resin, polyvinyl alcohol, polyvinylpyrrolidone, ethylcellulose, carboxymethylcellulose, gelatin, and copolymer resins thereof. The binder resin may be appropriately selected considering film strength, viscosity, viscosity of the remaining first ink, dispersion stability of the colorant, thermal stability, non-colorability, water resistance, and chemical resistance. The binder resin may be used in combination with other resins.

[0052] When a binder resin is incorporated, the binder resin content is not particularly limited. For example, the binder resin is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, in terms of solid content, in the first ink. Furthermore, the binder resin is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, in the first ink. If the binder resin content is less than 1% by mass, it is difficult to obtain the desired performance as a binder, and adhesion to the substrate tends to decrease. On the other hand, if the binder resin content exceeds 40% by mass, the viscosity of the first ink increases, and when performing inkjet printing, the ejection stability tends to decrease.

[0053] A dispersant is preferably included in the first ink to disperse the colored pigment when the first ink contains a colored pigment. The dispersant is not particularly limited. For example, dispersants include anionic surfactants, nonionic surfactants, polymeric dispersants, etc. Dispersants may be used in combination.

[0054] Examples of anionic surfactants include fatty acid salts, alkyl sulfate salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, lignin sulfonates, dialkyl sulfosuccinates, alkyl phosphate salts, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl sulfate salts, and their substituted derivatives.

[0055] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines, glycerin fatty acid esters, oxyethylene oxypropylene block polymers, and their substituted derivatives.

[0056] Polymeric dispersants that possess both acid and base values, and where the acid value is greater than the base value, are preferable from the viewpoint of obtaining more stable dispersion characteristics. Examples of polymeric dispersants include the PB series from Ajinomoto Fine Techno Co., Ltd., the Hinoact series from Kawaken Fine Chemical Co., Ltd., the Solspers series from Nippon Lubrizol Co., Ltd., the DISPARLON series from Kusumoto Chemical Co., Ltd., and the Efka® series from BASF Japan Ltd.

[0057] When a dispersant is included in the first ink, the amount of dispersant is appropriately determined depending on the type and amount of color pigment to be dispersed. For example, the amount of dispersant is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more, per 100 parts by mass of color pigment. Furthermore, the amount of dispersant is preferably 150 parts by mass or less, and more preferably 80 parts by mass or less, per 100 parts by mass of color pigment. If the amount of dispersant is less than 5 parts by mass, the color pigment tends to be difficult to disperse. On the other hand, if the amount of dispersant exceeds 150 parts by mass, raw material costs tend to increase, and the dispersion of the color pigment tends to be inhibited.

[0058] The solvent is preferably included in the first ink to dissolve the reactive oligomer and binder resin. The type of solvent is not particularly limited. For example, solvents include water, glycol ether solvents, acetate solvents, alcohol solvents, ketone solvents, ester solvents, hydrocarbon solvents, fatty acid ester solvents, aromatic solvents, etc. Solvents may be used in combination. In this embodiment, it is preferable that the solvent includes at least one of glycol ether solvents and acetate solvents. Both glycol ether solvents and acetate solvents have low viscosity and relatively high boiling points. Therefore, the first ink containing these as solvents has improved drying properties and better ejection stability when inkjet printing is performed.

[0059] Glycol ether 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 Examples include 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, and tripropylene glycol dimethyl ether.

[0060] Acetate 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, propylene glycol mono-sec-butyl ether acetate, and Examples include 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.

[0061] The solvent in this embodiment preferably has a boiling point of 150°C or higher, and more preferably 180°C or higher. Furthermore, the solvent preferably has a boiling point of 300°C or lower, and more preferably 280°C or lower. When the boiling point is within the above range, the resulting first ink has improved drying properties and superior ejection stability when inkjet printing is performed. When the boiling point of the solvent is below 150°C, the first ink tends to dry easily near the print head nozzle when inkjet printing is performed, and ejection stability tends to decrease.

[0062] The solvent content is not particularly limited. For example, the solvent content is preferably 1% by mass or more, and more preferably 3% by mass or more, in the first ink. Furthermore, the solvent content is preferably 30% by mass or less, and more preferably 20% by mass or less, in the first ink. If the solvent content is less than 1% by mass, the viscosity of the first ink increases, and the ejection stability tends to decrease when inkjet printing is performed. On the other hand, if the solvent content exceeds 30% by mass, the proportion of coloring pigments, reactive monomers, and binder resins that can be added to the first ink decreases, and it tends to be difficult to obtain the desired color development and performance.

[0063] In addition to the components described above, the first ink may contain optional components as appropriate. Examples of optional components include heat stabilizers, antioxidants, preservatives, defoamers, penetrating agents, reduction inhibitors, leveling agents, pH adjusters, polymerization inhibitors, wetting agents, ultraviolet absorbers, and light stabilizers.

[0064] In this embodiment, the glass transition temperature (Tg) of the resin component constituting the first ink is preferably 25°C or higher, and more preferably 30°C or higher. Furthermore, the glass transition temperature (Tg) of the resin component constituting the first ink is preferably 85°C or lower, and more preferably 80°C or lower. Because the Tg of the resin component constituting the first ink is within the above range, the first ink has excellent wettability and is easily applied to the substrate. In addition, the resulting first layer is easily made flexible enough to match the flexibility of the substrate.

[0065] Here, the Tg of the resin component constituting the first ink is the calculated glass transition temperature calculated from Fox's formula below. This calculated glass transition temperature is determined based on the type and amount of each monomer and oligomer component constituting the first layer. (Fox's formula) 1 / Calculation Tg=W1 / Tg(1)+W2 / Tg(2)+···+Wn / Tg(n) (1) Here, W1, W2, ...Wn represent the weight fraction (wt%) of each monomer or oligomer component (1), monomer or oligomer component (2), ...monomer or oligomer component (n) that constitute the first layer, relative to the total monomer and oligomer components. Tg(1), Tg(2), ...Tg(n) represent the glass transition temperature (in K) of the homopolymer of each monomer or oligomer component (1), monomer or oligomer component (2), ...monomer or oligomer component (n).

[0066] The viscosity of the first ink is not particularly limited. For example, the viscosity of the first ink is preferably 2 mPa·s or more, and more preferably 5 mPa·s or more. Furthermore, the viscosity is preferably 50 mPa·s or less, and more preferably 30 mPa·s or less. When the viscosity is within the above range, the first ink is less likely to cause ejection failures from the print head when inkjet printing is performed, and the ejection stability is excellent. In this embodiment, the viscosity of the first ink can be measured using a B-type viscometer (Toki Sangyo Co., Ltd., TVB-20LT, rotor rotation speed 60 rpm). The method for adjusting the viscosity within the above range is not particularly limited. For example, the viscosity can be adjusted by the amount of each component added, or by the type and amount of solvent added. The viscosity may also be adjusted by using viscosity modifiers such as thickeners as needed.

[0067] The surface tension of the first ink is not particularly limited. For example, the surface tension of the first ink is preferably 20 dyne / cm or more, and more preferably 22 dyne / cm or more, at 25°C. Furthermore, the surface tension of the first ink is preferably 40 dyne / cm or less, and more preferably 35 dyne / cm or less, at 25°C. When the surface tension is within the above range, the first ink exhibits excellent ejection stability when inkjet printing is performed. In this embodiment, the surface tension can be measured using a static surface tensile meter (plate method) (CBVP-A3, manufactured by Kyowa Interface Science Co., Ltd.).

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

[0069] Returning to the description of the first layer, the first layer is the layer to which the first ink described above is applied. Specifically, the first layer is produced by applying the first ink to the substrate and curing it by irradiating it with ultraviolet light.

[0070] The method for applying the first ink onto the substrate is not particularly limited. For example, the first ink can be applied by methods such as inkjet recording, screen printing, roll coater, or spray. Among these, it is preferable that the first ink in the first layer of this embodiment is an inkjet ink. As a result, the first layer is more prone to diffuse reflection compared to when it is formed by methods other than inkjet recording, such as screen printing. Consequently, the first layer has a glittery, shimmering appearance, and the brightness can be easily controlled.

[0071] The method of applying the first ink to the substrate by an inkjet recording method is not particularly limited. Examples of such methods include continuous methods such as a charge modulation method, a microdot method, a charged jet control method, an ink mist method, etc., and on-demand methods such as a piezo method, a pulse jet method, a bubble jet (registered trademark) method, an electrostatic attraction method, etc.

[0072] The application amount of the first ink is not particularly limited. For example, the ink application amount is preferably 3 g / m 2 or more, more preferably 5 g / m 2 or more. Also, the ink application amount is preferably 50 g / m 2 or less, more preferably 40 g / m 2 or less.

[0073] Next, the applied first ink is irradiated with ultraviolet rays and cured to form the first layer.

[0074] The curing conditions of the first ink are not particularly limited. For example, the UV irradiation intensity is preferably 50 mW / cm 2 or more, more preferably 100 mW / cm 2 or more. Also, the UV irradiation intensity is preferably 2000 mW / cm 2 or less, more preferably 1000 mW / cm 2 or less. By having the UV irradiation intensity within the above range, a properly cured first layer can be produced.

[0075] The UV irradiation energy (integrated light amount) is not particularly limited. For example, the integrated light amount is preferably 50 mJ / cm 2 or more, more preferably 100 mJ / cm 2 or more. Also, the integrated light amount is preferably 3000 mJ / cm 2 or less, more preferably 2000 mJ / cm 2 or less. By having the integrated light amount within the above range, a properly cured first layer can be produced.

[0076] The thickness of the cured first layer is not particularly limited. For example, the thickness of the first layer is preferably 3 μm or more, and more preferably 5 μm or more. Furthermore, the thickness of the first layer is preferably 50 μm or less, and more preferably 40 μm or less. When the thickness of the first layer is within the above range, the surface condition of the substrate of the decorative sheet is more uniform, and the formation of the second layer, described later, with an appropriate thickness makes it easier to exhibit excellent brightness even when various substrates are used.

[0077] (2nd layer) The second layer is a layer provided on top of the first layer, and is formed by applying a second ink containing metal particles to the first layer.

[0078] • Second ink The second ink contains metal particles. The metal particles are not particularly limited. For example, metal particles may include aluminum, silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, copper, etc. Among these, it is preferable that the metal particles include indium. This gives the decorative sheet better water resistance.

[0079] The average particle diameter of the metal particles is preferably 0.2 μm or more, and more preferably 0.25 μm or more. Furthermore, the average particle diameter of the metal particles is preferably 0.5 μm or less, and more preferably 0.4 μm or less. Having the average particle diameter within the above range allows the second ink to exhibit excellent ejection properties when applied by an inkjet method. Additionally, the second ink easily forms a second layer that exhibits excellent brightness. In this embodiment, the average particle diameter is the 50% cumulative frequency (hereinafter, P) of the area circle equivalent diameter in the number distribution measured by a flow-type particle image analyzer. 50 (Also known as) refers to P 50P is the diameter of the circle corresponding to the projected area of ​​the captured particle image (equivalent circle area diameter), and is the particle size at which the cumulative frequency in the cumulative distribution of this equivalent circle area diameter is 50%. Unless otherwise specified in this specification, "particle size" refers to the above "equivalent circle area diameter". Examples of flow-type particle image analyzers include the product names "FPIA-2100", "FPIA-3000", and "FPIA-3000S" manufactured by Sysmex Corporation. Furthermore, in this specification, "P" measured by a flow-type particle image analyzer is also used. 50 " refers to the value measured under the following measurement conditions. Imaging unit: High-magnification imaging unit Magnification: 40x (20x eyepiece x 2x objective lens) Measurement mode: HPF measurement mode Measurement time: Approximately 2 minutes Measurement solvent: Ethanol Binarization threshold setting coefficient: 85% Dilution ratio with solvent during measurement: 2000 times Sheath fluid: Ethanol

[0080] The content of metal particles is not particularly limited. For example, the content of metal particles in the second ink is preferably 1% by mass or more, and more preferably 2% by mass or more. Furthermore, the content of metal particles in the second ink is preferably 30% by mass or less, and more preferably 20% by mass or less. By having the content of metal pigment within the above range, the second layer is likely to have excellent brightness.

[0081] The second ink is preferably an ultraviolet-curable ink. Because the second ink is an ultraviolet-curable ink, the second layer has excellent solvent resistance to the third ink, even when the third layer described later is formed, and it is easier to maintain excellent brightness.

[0082] The second ink may contain, in addition to the metal particles described above, reactive monomers, reactive oligomers, photopolymerization initiators, binder resins, dispersants, solvents, and various optional components. The reactive monomers, reactive oligomers, photopolymerization initiators, binder resins, dispersants, solvents, and various optional components that may be included in the second ink are the same as those described above in relation to the first ink.

[0083] The second ink may be a colored ink. If the second ink is a colored ink, the second ink contains the colored pigment described above in relation to the first ink.

[0084] The viscosity of the second ink is not particularly limited. For example, the viscosity of the second ink is preferably 2 mPa·s or more, and more preferably 5 mPa·s or more. Furthermore, the viscosity is preferably 50 mPa·s or less, and more preferably 30 mPa·s or less. When the viscosity is within the above range, the first ink is less likely to cause ejection failures from the print head when inkjet printing is performed, and the ejection stability is excellent. The method for adjusting the viscosity within the above range is not particularly limited. For example, the viscosity can be adjusted by the amount of each component added, or by the type and amount of solvent added. The viscosity may also be adjusted by using viscosity modifiers such as thickeners as needed.

[0085] The surface tension of the second ink is not particularly limited. For example, the surface tension of the second ink is preferably 20 dyne / cm or more, and more preferably 22 dyne / cm or more, at 25°C. Furthermore, the surface tension of the second ink is preferably 40 dyne / cm or less, and more preferably 35 dyne / cm or less, at 25°C. When the surface tension is within the above range, the second ink exhibits excellent ejection stability when inkjet printing is performed.

[0086] The method for preparing the second ink in this embodiment is not particularly limited. For example, the second ink can be prepared by mixing the materials to be used, further dispersing the mixture using a disperser such as a roll mill, ball mill, colloid mill, jet mill, or bead mill, and then filtering it.

[0087] Returning to the description of the second layer, the second layer is the layer to which the second ink described above is applied. Specifically, the second layer can be produced by applying the second ink to the first layer and curing it by irradiating it with ultraviolet light.

[0088] The method for applying the second ink onto the first layer is not particularly limited. For example, the second ink can be applied by methods such as inkjet recording, screen printing, roll coater, or spray. Among these, it is preferable that the second ink in this embodiment is inkjet ink. This makes it easier for the second layer to exhibit the desired metallic appearance compared to when it is formed by methods other than inkjet recording, such as screen printing.

[0089] The method for applying the second ink onto the first layer using an inkjet recording method is not particularly limited. The method for applying the second ink onto the first layer using an inkjet recording method, the amount of ink applied, the curing conditions, etc., are the same as those described above for the first ink.

[0090] The thickness of the cured second layer is not particularly limited. For example, the thickness of the second layer is preferably 0.1 μm or more, and more preferably 0.2 μm or more. Furthermore, the thickness of the second layer is preferably 5 μm or less, and more preferably 3 μm or less. By having the thickness of the second layer within the above range, the decorative sheet has a uniform surface condition of the substrate due to the first layer, and the second layer is formed with an appropriate thickness. As a result, the decorative sheet is more likely to exhibit a superior brightness.

[0091] In the second layer, the composition ratio of metal particles to the resin components constituting the second layer is preferably 1:0.025 to 1:10, and more preferably 1:0.25 to 1:2.5. By having the composition ratio within the above range, the second layer exhibits excellent brightness. Furthermore, even when the third layer, which will be described later, is formed, the second layer has excellent solvent resistance to the third ink, and its excellent brightness is easily maintained.

[0092] (3rd layer) The third layer is a preferably provided layer, and is a layer on which a third ink is applied on the second layer. The provision of the third layer improves the abrasion resistance and water resistance of the decorative sheet.

[0093] • Third Ink The third ink is preferably a water-based ink or a solvent-based ink. The third ink may also be a clear ink or a colored ink. When a colored ink is used as the third ink, metallic decorative sheets of various colors can be produced. If the third ink is a colored ink, it contains a coloring pigment or dye. The coloring pigment is the same as the coloring pigment described above in relation to the first ink.

[0094] The dyes that may be included in the third ink are not particularly limited. For example, dyes include basic dyes, acid dyes, direct dyes, soluble vat dyes, acid mordant dyes, mordant dyes, reactive dyes, vat dyes, sulfur dyes, etc. Among these, dyes that are azo dyes, rhodamine dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, triphenylmethane dyes, diphenylmethane dyes, methylene blue, etc.

[0095] If a dye is included, the dye content is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more, in the third ink. Furthermore, the dye content is preferably 20% by mass or less, and more preferably 15% by mass or less, in the third ink. When the dye content is within the above range, the resulting decorative sheet is more likely to develop color sufficiently.

[0096] The third ink may contain, as appropriate, a binder resin, a dispersant, a solvent (including water), and various optional components.

[0097] The binder resin is suitably formulated, for example, to adjust the viscosity of the third ink, or to adjust the hardness of the resulting third layer. Examples of binder resins are similar to those described above in relation to the second ink.

[0098] In this embodiment, the third ink preferably contains a polyurethane resin, polyester resin, or polyacrylic resin among the binder resins. This ensures that the resulting decorative sheet does not impair the texture of the base material. In particular, when the base material is synthetic leather, the third ink preferably contains a polyurethane resin. On the other hand, when the base material is a polycarbonate resin or an acrylic resin, the third ink preferably contains a polyester resin or an acrylic resin.

[0099] Polyurethane resins are not particularly limited. Examples include polyether-based polyurethane resins, polyester-based polyurethane resins, polyester-polyether-based polyurethane resins, and polycarbonate-based polyurethane resins.

[0100] The weight-average molecular weight (Mw) of the polyurethane resin is not particularly limited. For example, Mw is preferably 5,000 or more, more preferably 10,000 or more. Mw is preferably 100,000 or less, more preferably 50,000 or less. When Mw is within the above range, the third ink containing such a polyurethane resin exhibits excellent ejection stability when inkjet printing is performed.

[0101] Polyester resins are not particularly limited. Examples of polyester resins include polyethylene terephthalate (PET), polytetramethylene terephthalate, polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate, polyhydroxybutyric acid (PHB), polyhydroxyalkanoate (PHA), polybutylene succinate (PBS), polylactic acid (PLA), and polybutylene naphthalate (PBN).

[0102] The weight-average molecular weight (Mw) of the polyester resin is not particularly limited. For example, Mw is preferably 5,000 or more, more preferably 10,000 or more. Mw is preferably 100,000 or less, more preferably 50,000 or less. When Mw is within the above range, the third ink containing such a polyester resin exhibits excellent ejection stability when inkjet printing is performed.

[0103] Polyacrylic resins are not particularly limited. For example, polyacrylic resins include polymers of acrylic acid esters (acrylates) or methacrylic acid esters (methacrylates). More specifically, polyacrylic resins include polymers of alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, and 2-ethylhexyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, and 2-ethylhexyl methacrylate; hydroxyl group-containing acrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate; and hydroxyl group-containing methacrylic acid esters such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl methacrylate. These may be used in combination.

[0104] The weight-average molecular weight (Mw) of the polyacrylic resin is not particularly limited. For example, Mw is preferably 5,000 or more, more preferably 10,000 or more. Mw is preferably 100,000 or less, more preferably 50,000 or less. When Mw is within the above range, the third ink containing such polyacrylic resin exhibits excellent ejection stability when inkjet printing is performed.

[0105] Returning to the overall explanation of the binder resin, the binder resin content is not particularly limited. For example, the binder resin is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, in terms of solid content, in the third ink. Furthermore, the binder resin is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, in the third ink. When the binder resin content is within the above range, the third ink exhibits excellent ejection stability when inkjet printing is performed. In addition, the third ink exhibits excellent adhesion to the second layer.

[0106] The dispersant is suitably formulated to disperse the pigment. The dispersant is not particularly limited. For example, dispersants include anionic surfactants, nonionic surfactants, polymeric dispersants, etc. These are similar to those mentioned above in relation to the second ink.

[0107] The amount of dispersant is appropriately determined depending on the type and amount of pigment to be dispersed. For example, the amount of dispersant is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more, per 100 parts by mass of pigment. Furthermore, the amount of dispersant is preferably 150 parts by mass or less, and more preferably 80 parts by mass or less, per 100 parts by mass of pigment. When the amount of dispersant is within the above range, the pigment is easily dispersed.

[0108] The solvent is a liquid component used to dissolve the binder resin. The type of solvent is not particularly limited. The solvent can be appropriately selected depending on whether the third ink is a water-based ink or a solvent-based ink, etc. Examples of solvents include water, glycol ether-based solvents, acetate-based solvents, alcohol-based solvents, ketone-based solvents, ester-based solvents, hydrocarbon-based solvents, fatty acid ester-based solvents, aromatic solvents, etc.

[0109] When the third ink is a solvent-based ink, it is preferable that the solvent contains at least one of a glycol ether-based solvent and an acetate-based solvent. Both glycol ether-based solvents and acetate-based solvents have low viscosity and relatively high boiling points. Therefore, the third ink containing these as solvents has improved drying properties and superior ejection stability when inkjet printing is performed. When the third ink is a solvent-based ink, the glycol ether-based solvent and acetate-based solvent can be the same as those described above in relation to the second ink.

[0110] The solvent in this embodiment preferably has a boiling point of 150°C or higher, and more preferably 180°C or higher. Furthermore, the solvent preferably has a boiling point of 300°C or lower, and more preferably 280°C or lower. When the boiling point is within the above range, the resulting third ink has improved drying properties and superior ejection stability when inkjet printing is performed.

[0111] The solvent content is not particularly limited. For example, the solvent content is preferably 50% by mass or more, and more preferably 60% by mass or more, in the third ink. Furthermore, the solvent content is preferably 99% by mass or less, and more preferably 80% by mass or less, in the third ink. By having the solvent content within the above range, the third ink is easy to blend with various components, has an appropriate viscosity, and exhibits excellent ejection stability when inkjet printing is performed.

[0112] In addition to the components described above, the third ink of this embodiment may contain optional components as appropriate. Optional components include heat stabilizers, antioxidants, preservatives, defoamers, penetrating agents, reduction inhibitors, leveling agents, pH adjusters, polymerization inhibitors, UV absorbers, and light stabilizers.

[0113] The viscosity of the third ink is not particularly limited. For example, the viscosity of the third ink is preferably 2 mPa·s or more, and more preferably 5 mPa·s or more. Furthermore, the viscosity is preferably 50 mPa·s or less, and more preferably 30 mPa·s or less. When the viscosity is within the above range, the third ink is less likely to cause ejection failures from the print head when inkjet printing is performed, and the ejection stability is excellent. The method for adjusting the viscosity within the above range is not particularly limited. For example, the viscosity can be adjusted by the amount of each component added, or by the type and amount of solvent added. The viscosity may also be adjusted by using viscosity modifiers such as thickeners as needed.

[0114] The surface tension of the third ink is not particularly limited. For example, the surface tension of the third ink is preferably 20 dyne / cm or more, and more preferably 22 dyne / cm or more, at 25°C. Furthermore, the surface tension of the third ink is preferably 40 dyne / cm or less, and more preferably 35 dyne / cm or less, at 25°C. When the surface tension is within the above range, the third ink exhibits excellent ejection stability when inkjet printing is performed.

[0115] The method for preparing the third ink in this embodiment is not particularly limited. For example, the third ink can be prepared by mixing the materials to be used, further dispersing the mixture using a disperser such as a roll mill, ball mill, colloid mill, jet mill, or bead mill, and then filtering it.

[0116] Returning to the explanation of the third layer, the third layer is the layer to which the third ink described above is applied. Specifically, the third layer is created by applying the third ink to the second layer and drying it.

[0117] The method for applying the third ink onto the second layer is not particularly limited. For example, the third ink can be applied by methods such as inkjet recording, screen printing, roll coater, or spray. Among these, it is preferable that the third ink in this embodiment is inkjet ink. This makes it easier to synchronize the third layer with the second layer and to apply the third ink only to the necessary parts, compared to when the third layer is formed by methods other than inkjet recording, such as screen printing.

[0118] The method for applying the third ink onto the second layer using an inkjet recording method is not particularly limited. The method for applying the third ink onto the second layer using an inkjet recording method, the amount of ink applied, etc., are the same as the conditions described above for the first ink.

[0119] The amount of the third ink applied is not particularly limited. For example, the amount of ink applied is 10 g / m² relative to the substrate. 2 Preferably, it is 20 g / m 2 It is more preferable that the amount is greater than or equal to the above. Also, the ink application rate should be 200 g / m². 2 Preferably, it is 180 g / m². 2 The following is more preferable:

[0120] Next, the applied third ink is dried to remove the solvent, forming a third layer.

[0121] The drying conditions for the third ink are not particularly limited. For example, drying may be performed by heat treatment at 50-250°C. Such drying removes the solvent from the third ink. It is preferable that drying is performed simultaneously with or immediately after the third ink is applied to the second layer in order to prevent bleeding of the third layer.

[0122] The thickness of the dried third layer is not particularly limited. For example, the thickness of the third layer is preferably 5 μm or more, and more preferably 10 μm or more. Furthermore, the thickness of the third layer is preferably 100 μm or less, and more preferably 90 μm or less. When the thickness of the third layer is within the above range, the decorative sheet has better abrasion resistance and water resistance. In addition, when a colored ink is used as the third ink, metallic decorative sheets of various colors can be produced.

[0123] As described above, the decorative sheet of this embodiment improves the ink resistance, solvent resistance, and smoothness of the substrate by the first layer. Furthermore, the first ink constituting the first layer is an ultraviolet-curable ink, and can constitute a first layer with a large film thickness. Therefore, the substrate's surface condition is easily made uniform by the presence of the first layer. As a result, the decorative sheet can be used with various substrates that have different surface conditions, and the surface condition can be made uniform for any substrate, making it easier to improve the perceived brightness by adding the second layer. [Examples]

[0124] The present invention will be described more specifically below with reference to examples. The present invention is not limited in any way to these examples.

[0125] The raw materials used are listed below. <First Ink> (UV-curable oligomer) UV-curable oligomer 1: CN996, urethane acrylate oligomer, Tg: 281K, manufactured by Arkema. UV-curable oligomer 2: EBECRYL 8810, urethane acrylate oligomer, Tg: 327K, manufactured by Daicel Ornex Corporation. (UV-curable monomer) UV-curable monomer 1: ACMO, acrylic morpholine, Tg: 418K, manufactured by KJ Chemicals. UV-curable monomer 2: SR479D, tridecyl acrylate, Tg: 218K, manufactured by Arkema. UV-curable monomer 3:A9300-1CL, caprolactam-modified trisacryloxyethyl isocyanurate, Tg:371K, manufactured by Shin-Nakamura Chemical Industry Co., Ltd. UV-curable monomer 4: AO-MA, methyl 2-(allyloxymethyl)acrylate, Tg: 355K, manufactured by Nippon Shokubai Co., Ltd. UV-curable monomer 5:V#150, tetrahydrofurfuryl acrylate, Tg:261K, manufactured by Osaka Organic Chemical Industry Co., Ltd. (Polymerization initiator) Polymerization initiator 1: Irgacure184, 1-hydroxycyclohexylphenyl ketone, manufactured by IGM Resins BV. (Polymerization inhibitor) Polymerization inhibitor 1: hydroxy TEMPO, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, manufactured by Nanjing Lepu Shipin Co., Ltd. (Wetting agent) Wetting agent 1: F-556, oligomer containing fluorine-containing groups, hydrophilic groups, and lipophilic groups, manufactured by DIC Corporation <Second Ink> (Metal particle dispersion) MB1: MIJ-F406PM, aluminum particle propylene glycol monomethyl ether acetate dispersion, manufactured by Toyo Aluminum Co., Ltd., NV (solids content): 10%, average particle size: 0.5 μm MB2:49CJ-0620, Indium particle MMB dispersion, manufactured by Oike Metallic Design Co., Ltd., NV (solids content): 20%, average particle size: 0.28 μm (solvent) Solvent 1: Solfit MMB, 3-Methoxy-3-methyl-1-butanol, manufactured by Kuraray Co., Ltd. Solvent 2: GBL, γ-butyrolactone, manufactured by Kuraray Co., Ltd. (UV-curable monomer) UV-curable monomer 4:AO-XA UV-curable monomer 5:CN2304, polyester acrylate oligomer, manufactured by Arkema. UV-curable monomer 6:SR444NS, pentaerythritol triacrylate, manufactured by Arkema. (Polymerization initiator) Polymerization initiator 2: Irgacure 819, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, manufactured by IGM Resins BV. (Polymerization inhibitor) Polymerization inhibitor 2: IRGASTABUV10, manufactured by BASF. Polymerization inhibitor 3: GENORAD21, manufactured by RANH. <Third Ink> (Solvent-based ink) IPX-HF: Acrylic screen ink, manufactured by Teikoku Ink Mfg. Co., Ltd., polyester resin. (Water-based ink) PUE-800FW: Polycarbonate urethane dispersion, manufactured by Murayama Chemical Research Institute Co., Ltd. (Wetting agent) Wetting agent 2: KS-NF30, perfluoroalkyl compound, manufactured by AGC Seimi Chemical Co., Ltd. <Base material> Substrate 1: PMMA / PC, Panlite PC-N501, Thickness: 400 μm, manufactured by Teijin Limited. Base material 2: Synthetic leather, QUOLE, Thickness: 500 μm, manufactured by Seiren Co., Ltd.

[0126] <Example 1> According to the formulations (unit: parts by mass) shown in Tables 1 to 3 below, a UV clear (1) ink was prepared as the first ink, a UV-based (1) ink as the second ink, and a solvent-based (1) ink as the third ink. In Table 1, the Tg of the resin component constituting the first ink is the calculated glass transition temperature calculated from Fox's formula described above. Each of the obtained inks was applied to the substrate 1 to the thickness shown in Tables 4 and 5 below to create a decorative sheet. The conditions for forming the first to third layers are as follows.

[0127] (Conditions for the formation of the first layer) The substrate was coated with the first ink under the inkjet printing conditions 1 described below, and then irradiated with ultraviolet light under the ultraviolet irradiation conditions 1 described below to form the first layer (thickness 20 μm). • Inkjet printing conditions 1 Nozzle diameter 40 μm Voltage 70V Puzzle width 10 μs Drive frequency 10kHz Resolution: 400 x 800 dpi Application amount: 20g / m² 2 ·Ultraviolet irradiation conditions 1 Lamp type: Metal halide lamp manufactured by Integration Technologies. Irradiation intensity (measurement wavelength 365nm) 480mW / cm 2 Integrated light intensity (measured at a wavelength of 365 nm): 1040 mJ / cm² 2 Irradiation height: 45cm

[0128] (Conditions for the formation of the second layer) The substrate on which the first layer was formed was coated with the second ink under the inkjet printing conditions 2 described below, and then irradiated with ultraviolet light under the ultraviolet irradiation conditions 2 described below to form the second layer (thickness 3 μm). • Inkjet printing conditions 2 Nozzle diameter 40 μm Voltage 70V Puzzle width 10 μs Drive frequency 10kHz Resolution: 400 x 800 dpi Coating amount 5g / m 2 • Solvent drying conditions The product was dried using a tabletop dryer at 50°C for 3 minutes. ·Ultraviolet irradiation conditions 2 Lamp type: Metal halide lamp manufactured by Integration Technologies. Irradiation intensity (measurement wavelength 365nm) 480mW / cm 2 Integrated light intensity (measured at a wavelength of 365 nm): 1040 mJ / cm² 2 Irradiation height: 45cm

[0129] (Conditions for the formation of the third layer) A third ink was applied to the substrate on which the first and second layers had formed, under the following coating conditions 1, and dried under the following drying conditions 1 to form the third layer (thickness 80 μm). (Solvent-based coating conditions) Screen coating method, mesh #200, 3 coats + mesh #100, 3 coats (Solvent-based drying conditions) 80℃ for 120 minutes (Water-based coating conditions) Bar coater application method, #20 (Water-based drying conditions) 80℃ for 3 minutes

[0130] Based on the above, the decorative sheet of Example 1 was prepared. The obtained decorative sheet was evaluated for brightness, ink wettability, water resistance, and abrasion resistance according to the following evaluation method. The results are shown in Table 4.

[0131] <Examples 2-18, Comparative Examples 1-8> Decorative sheets were prepared using the same method as in Example 1, except that the formulations were changed as shown in Tables 1 to 5. The brightness, ink wettability, water resistance, and abrasion resistance of the obtained decorative sheets were evaluated. The results are shown in Tables 4 to 6.

[0132] (Brightness (Glossiness)) Brightness was measured using a gloss checker (IG-410, manufactured by Horiba, Ltd.) at a range of 1000, and evaluated according to the following evaluation criteria. ○: It had a metallic, glossy appearance, and its gloss level was 200 or higher. △: A metallic, glossy appearance was noticeable, with a gloss level value between 50 and 200. ×: It lacked a metallic shine and its gloss level was below 50.

[0133] (Ink wettability) The ink application was evaluated according to the following evaluation criteria. ○: The ink of the second layer was applied evenly on top of the first layer without repelling. △: The ink from the second layer was slightly repelled from the first layer, but was generally applied evenly. ×: The ink from the second layer was repelled from the first layer, resulting in uneven application.

[0134] (Water resistance (high temperature and high humidity test)) Using a constant temperature and humidity chamber (IG-410, manufactured by Horiba, Ltd.), the samples were placed at a temperature of 50°C and a relative humidity of 95% for 500 hours. After this, glossiness was measured using the same measurement method as for luminance, and evaluated according to the following evaluation criteria. ○: It had a metallic, glossy appearance, and its gloss level was 200 or higher. △: A metallic, glossy appearance was noticeable, with a gloss level value between 50 and 200. ×: It lacked a metallic shine and its gloss level was below 50.

[0135] (Abrasion resistance) Using a Taber abrasion tester (No. 101-H, Yasuda Seiki Seisakusho Co., Ltd.), the abrasion resistance was measured at a load of 1 kg for 2000 cycles and evaluated according to the following evaluation criteria. ○: The second layer was hardly worn away, and the metallic sheen remained. △: Although part of the second layer had been scraped away, a metallic sheen remained. ×: The second layer was almost completely removed, and the metallic sheen was no longer present.

[0136] [Table 1]

[0137] [Table 2]

[0138] [Table 3]

[0139] [Table 4]

[0140] [Table 5]

[0141] [Table 6]

[0142] As shown in Tables 4 to 6, the decorative sheets of Examples 1 to 18 of the present invention all exhibited excellent brightness and superior coating film properties such as wettability and water resistance. In particular, the decorative sheets of Examples 1 to 14, which had a third layer, also exhibited excellent abrasion resistance, and the decorative sheets of Examples 1 to 6 and 9 to 14, in which the thickness of the third layer was 10 μm or more, exhibited particularly excellent abrasion resistance.

Claims

1. The material comprises a base material, a first layer provided on the base material, a second layer provided on the first layer, and a third layer provided on the second layer. The first layer is a layer to which the first ink is applied. The first ink is an ultraviolet-curing ink, The second layer is a layer to which a second ink containing metal particles is applied. The aforementioned third layer is a layer to which the third ink is applied. The third ink is either a water-based ink or a solvent-based ink. The thickness of the third layer is 5 to 100 μm. A decorative sheet wherein the glass transition temperature (Tg) of the resin component constituting the first ink is 25 to 85°C.

2. A material comprising a base material, a first layer provided on the base material, a second layer provided on the first layer, and a third layer provided on the second layer, The first layer is a layer to which the first ink is applied. The first ink is an ultraviolet-curing ink, The second layer is a layer to which a second ink containing metal particles is applied. The aforementioned third layer is a layer to which the third ink is applied. The third ink is either a water-based ink or a solvent-based ink. The thickness of the third layer is 5 to 100 μm. The thickness of the first layer is 3 to 50 μm. The second layer has a thickness of 5 μm or less, and is used as a decorative sheet.

3. The decorative sheet according to claim 1 or 2, wherein the third ink comprises a polyurethane resin, a polyester resin, or a polyacrylic resin.

4. The decorative sheet according to any one of claims 1 to 3, wherein the second ink is an inkjet ink.

5. The decorative sheet according to any one of claims 1 to 4, wherein the first ink is an inkjet ink.

6. The decorative sheet according to any one of claims 1 to 5, wherein the average particle size of the metal particles is 0.2 to 0.5 μm.

7. The decorative sheet according to any one of claims 1 to 6, wherein the composition ratio of the metal particles to the resin component constituting the second layer is 1:0.025 to 1:

10.

8. The decorative sheet according to any one of claims 1 to 7, wherein the metal particles include indium.

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