Decorative sheet and method for manufacturing decorative sheet

Abstract

To provide a decorative sheet capable of reducing the occurrence of delamination and a method for producing the decorative sheet.SOLUTION: There is provided a decorative sheet 10 which comprises a base material 11, a pattern layer 12, an adhesive layer 13, a transparent resin layer 14 and a surface protective layer 15 in this order, wherein the adhesive layer 13 is composed of a polyether urethane resin and the polyether urethane resin contains at least one of a polyethylene ether glycol, a polypropylene ether glycol and a polytetramethylene ether glycol having a number average molecular weight of 200 or more, an isocyanate compound having a cyclic structure and a compound having at least two hydroxy groups and at one carboxy group substituted with an alkanolamine as resin components and has a hydroxy value of 10 mgKOH / g or more and 150 mgKOH / g or less and an acid value of 5 mgKOH / g or more and 80 mgKOH / g or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a decorative sheet and a method for producing a decorative sheet. [Background technology]

[0002] For interior or exterior building materials such as walls, ceilings, floors, and entrance doors, and for fixtures or construction materials such as window frames, doors, handrails, baseboards, moldings, and trim, decorative sheets are generally laminated to the adherends, which are generally made of metal materials such as steel plates, resin materials, or wood materials. Many decorative sheets are laminates, and decorative sheets used for building exteriors, bathrooms, and the like, in particular, can experience problems such as moisture penetrating from the edges of the decorative sheet into the interior of the sheet, causing delamination.

[0003] In general, when manufacturing a decorative sheet, which is a laminate, an adhesive layer may be provided. This adhesive layer is generally made of acrylic resin, polyurethane resin, epoxy resin, or polyester resin (Patent Document 1). In such cases, delamination may occur between the adhesive layer and the transparent resin layer formed on the adhesive layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4737722 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to solve the above-mentioned problems, the present invention aims to provide a decorative sheet that can reduce the occurrence of interlayer delamination (particularly the occurrence of interlayer delamination between an adhesive layer and a transparent resin layer), and a method for manufacturing such a decorative sheet. [Means for solving the problem]

[0006] As a result of extensive research, the inventors discovered that the above-mentioned goals can be achieved by using a decorative sheet that uses a resin containing specific elements in the adhesive layer (also called an anchor layer or anchor coat layer), and thus arrived at the present invention. In order to solve the above problems, a decorative sheet according to one embodiment of the present invention is a decorative sheet comprising, in this order, a polyolefin substrate, a pattern layer, an anchor coat layer, a transparent resin layer mainly composed of polypropylene, and a top coat layer, wherein the anchor coat layer is composed of a polyether-based urethane resin, and the polyether-based urethane resin contains, as resin components, a polyalkylene glycol having a number average molecular weight of 200 or more and selected from polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), and polytetramethylene ether glycol (PTMG), an isocyanate compound having a cyclic structure, and a compound having at least two hydroxyl groups and at least one carboxy group substituted with an alkanolamine, and has a hydroxyl value in the range of 10 mgKOH / g or more and 150 mgKOH / g or less, and an acid value in the range of 5 mgKOH / g or more and 80 mgKOH / g or less. Effect of the Invention

[0007] According to one aspect of the present invention, there is provided a decorative sheet that is capable of reducing the occurrence of delamination (particularly the occurrence of delamination between an adhesive layer and a transparent resin layer), and a method for producing the decorative sheet. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a cross-sectional structure of a decorative sheet according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Configuration of decorative sheet] The configuration of a decorative sheet according to one embodiment of the present invention will be described with reference to the drawings. Here, the configuration shown in Fig. 1 is schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc. differ from the actual ones. Furthermore, the embodiments shown below are examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the materials, shapes, structures, etc. of the components described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims described in the claims.

[0010] Fig. 1 is a cross-sectional view showing the configuration of a decorative sheet 10 according to this embodiment. The decorative sheet 10 comprises a substrate (polyolefin substrate) 11, a pattern layer 12 formed on the substrate 11, an adhesive layer (anchor coat layer) 13 formed on the pattern layer 12, a transparent resin layer 14 formed on the adhesive layer 13, and a surface protective layer (top coat layer) 15 formed on the transparent resin layer 14. Hereinafter, as this embodiment, a decorative sheet 10 in which the transparent resin layer 14 is bonded via the adhesive layer 13 to the substrate 11 on which the pattern layer 12 is printed, and further the surface protective layer 15 is provided, will be described with reference to Fig. 1.

[0011] (adhesive layer) The adhesive layer 13 is a layer provided for bonding the design layer 12 and the transparent resin layer 14 together. The adhesive layer 13 is made of a polyether-based urethane resin, and is formed by using a typical coating method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating. The polyether-based urethane resin constituting the adhesive layer 13 is formed (synthesized) containing, as a resin component, at least one polyalkylene glycol selected from polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), and polytetramethylene ether glycol (PTMG) having a number average molecular weight of 200 or more, an isocyanate compound having a cyclic structure, and a compound having at least two hydroxyl groups and at least one carboxyl group substituted with an alkanolamine. Furthermore, this polyether-based urethane resin has a hydroxyl value in the range of 10 mgKOH / g to 150 mgKOH / g, and an acid value in the range of 5 mgKOH / g to 80 mgKOH / g. The polyether-based urethane resin of the present embodiment can be synthesized by a known technique, that is, an addition polymerization reaction between a polyol and a polyisocyanate. The adhesive layer 13 can be hardened by making the terminal of the urethane resin a hydroxyl group and adding an appropriate amount of a hardener such as an isocyanate.

[0012] The polyalkylene glycol constituting the polyether-based urethane resin of this embodiment may be, for example, at least one of polytetramethylene ether glycol (PTMEG), polytetramethylene glycol (PTMG), and pentamethylene glycol (PMG). These polyalkylene glycols increase the flexibility of the polyether-based urethane resin, and can impart excellent flexibility to the entire adhesive layer 13. The polyalkylene glycol constituting the polyether-based urethane resin of the present embodiment may be hexamethylene glycol. The polyalkylene glycol constituting the polyether-based urethane resin of the present embodiment has a number average molecular weight of at least 200, and preferably at least 500. The number average molecular weight is preferably at most 5000, and more preferably at most 2000.

[0013] The isocyanate compound having a cyclic structure constituting the polyether-based urethane resin of the present embodiment is, for example, 1,2-bis(isocyanatomethyl)cyclohexa ... Nya , 1,3-bis(isocyanatomethyl)cyclohexane (H-XDI) can be used. These isocyanate compounds can increase the flexibility of the polyether-based urethane resin, and can impart excellent flexibility to the entire adhesive layer 13. Among the above-mentioned materials, 1,3-bis(isocyanatomethyl)cyclohexane (H-XDI) is preferable in terms of flexibility. Furthermore, since the above-mentioned isocyanate compounds have a three-dimensional structure, the polyether-based urethane resin constituting the adhesive layer 13 can be imparted with the necessary hardness without adding a separate crosslinking agent. Furthermore, the isocyanate compound having a cyclic structure constituting the polyether-based urethane resin of this embodiment may be toluene diisocyanate. The content of the isocyanate compound is preferably in the range of 5 parts by mass or more and 100 parts by mass or less, and more preferably in the range of 10 parts by mass or more and 60 parts by mass or less, relative to 100 parts by mass of the polyalkylene glycol.

[0014] The compound having at least two hydroxyl groups and at least one carboxy group substituted with an alkanolamine that constitutes the polyether-based urethane resin of this embodiment can be, for example, dimethylolpropionic acid whose carboxy group has been neutralized with an alkanolamine. In this embodiment, the compound neutralized with an alkanolamine is preferably dimethylolpropionic acid, but the present invention is not limited to this (dimethylolpropionic acid). In this embodiment, the compound neutralized with an alkanolamine may be, for example, dimethylolbutanoic acid, dimethylolheptanoic acid, or methylolbutyric acid. The content of the compound neutralized with the alkanolamine is preferably in the range of 2 parts by mass or more and 50 parts by mass or less, and more preferably in the range of 5 parts by mass or more and 30 parts by mass or less, per 100 parts by mass of the polyalkylene glycol.

[0015] The alkanolamine of the present embodiment may be at least one selected from the group consisting of, for example, triisopanolamine, methylethanolamine, methyldiethanolamine, ethylethanolamine, and ethyldiethanolamine. These alkanolamines are easily available, and can increase the versatility of the polyether-based urethane resin. In addition, with these alkanolamines, the alkanolamine (unreacted molecules) that has not reacted with the carboxy group easily evaporates and is unlikely to remain as an impurity (unreacted residue) in the polyether-based urethane resin, so that the expected physical properties of the polyether-based urethane resin can be easily obtained. Among the above-mentioned materials, triisopanolamine is preferable because it easily reacts with the carboxy group and improves the affinity and adhesion to water. In addition, the alkanolamine of the present embodiment may be ethanolamine or triisopropanolamine.

[0016] The polyether-based urethane resin of the present embodiment may have a hydroxyl value in the range of 10 mgKOH / g to 150 mgKOH / g, more preferably in the range of 50 mgKOH / g to 100 mgKOH / g, and most preferably in the range of 75 mgKOH / g to 85 mgKOH / g. .Ma In addition, if the hydroxyl value exceeds 150 mgKOH / g, the water resistance may decrease, and if the hydroxyl value exceeds 150 mgKOH / g, it becomes difficult to obtain various components that constitute the polyether-based urethane resin, which is problematic from the viewpoint of versatility.

[0017] The polyether-based urethane resin of the present embodiment may have an acid value in the range of 5 mgKOH / g to 80 mgKOH / g, more preferably in the range of 10 mgKOH / g to 50 mgKOH / g, and most preferably in the range of 25 mgKOH / g to 35 mgKOH / g. .MaIn addition, if the acid value exceeds 80 mgKOH / g, the water resistance may decrease, and if the acid value exceeds 80 mgKOH / g, it becomes difficult to obtain various components that constitute the polyether-based urethane resin, which is problematic from the viewpoint of versatility.

[0018] The molecular weight of the polyether-based urethane resin of this embodiment is not particularly limited, and for example, taking into consideration the printability of the adhesive layer 13 formed by normal printing and the various performance properties of the decorative sheet 10, it is desirable for the mass average molecular weight (Mw) to be in the range of 5,000 to 100,000. Within the above numerical range, printability can be easily improved.

[0019] The polyether-based urethane resin of this embodiment may contain at least one of an isocyanate compound different from the isocyanate compound having a cyclic structure, such as 1,3-bis(isocyanatomethyl)cyclohexane (H-XDI), and an epoxy compound, as a curing agent for increasing the crosslink density of the polyether-based urethane resin. In other words, the adhesive layer 13 of this embodiment is a layer formed from an aqueous ink that contains the polyether-based urethane resin as the main component of the resin component, and further contains at least one of an isocyanate compound different from the isocyanate compound having a cyclic structure, and an epoxy compound, as a secondary component of the resin component, which is a curing agent for increasing the crosslink density of the polyether-based urethane resin. The isocyanate compound used as a curing agent for increasing the crosslink density of the polyether-based urethane resin of the present embodiment is not particularly limited, and can be appropriately selected from commercially available curing agents including, for example, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate and hydrogenated products thereof, or diphenylmethane diisocyanate and hydrogenated products thereof. The epoxy compound used as a curing agent for increasing the crosslink density of the polyether-based urethane resin of the present embodiment is not particularly limited, and may be a monofunctional epoxy compound having one epoxy group, or a polyfunctional epoxy compound having two or more epoxy groups. These may also be used in combination.

[0020] Examples of monofunctional epoxy compounds include silane coupling agents having an epoxy group, such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylethyldiethoxysilane. Examples of monofunctional epoxy compounds other than silane coupling agents having an epoxy group include phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, ethyl diethylene glycol glycidyl ether, dicyclopentadiene glycidyl ether, and 2-hydroxyethyl glycidyl ether. These monofunctional epoxy compounds may be used alone or in combination of two or more.

[0021] Examples of polyfunctional epoxy compounds include hydroquinone diglycidyl ether, resorcinol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, cyclohexene diol diglycidyl ether, cyclohexane dimethanol diglycidyl ether, dicyclopentadiene diol diglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, phenol novolac type epoxy resin, cresol novolac type epoxy resin, epoxidized polybutadiene, etc. Any one of these polyfunctional epoxy compounds may be used alone, or two or more may be used in combination.

[0022] The method for bonding the transparent resin layer 14 to the substrate 11 provided with the pattern layer 12 may be via an adhesive layer 13, and various lamination techniques such as thermal lamination, extrusion lamination, dry lamination, and sand lamination can be used.

[0023] (base material) The resin constituting the substrate 11, i.e., the resin component, is preferably polyolefin or polyester, and is most preferably polyolefin in terms of versatility. The resin constituting the substrate 11 can be arbitrarily selected from existing materials such as polyethylene, polypropylene, polybutylene, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. In addition, examples of materials other than the polyolefin-based resins include α-olefins (e.g., 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl ...4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl These include homopolymers or copolymers of two or more types of α-olefins (e.g., hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.) as well as copolymers of ethylene or α-olefins with other monomers, such as ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate copolymer.

[0024] In order to improve adhesion with adjacent layers, the substrate 11 may be subjected to a surface treatment such as corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet treatment, dichromate treatment, etc. Furthermore, a primer layer (not shown) may be provided between the substrate 11 and the design layer 12 to ensure adhesion. If the base material 11 is made of polyolefin or polyester, adhesion to the design layer 12 described below is ensured, and if the base material 11 is made of polyolefin, adhesion to the design layer 12 is even more ensured.

[0025] When it is desired to impart concealing properties to the decorative sheet 10, a concealing colored sheet may be used for the substrate 11, or a concealing layer (not shown) may be provided on the substrate 11 and below the pattern layer 12. When a colored sheet is used as the substrate 11, a colorant may be added to the resin material constituting the substrate 11 to color it. As the colorant, for example, inorganic pigments (titanium oxide, carbon black, etc.) and organic pigments (phthalocyanine blue, etc.) as well as dyes may be used. As the colorant of this embodiment, one or more types may be selected from known or commercially available colorants, and the amount added may be adjusted so that the desired concealing properties and design properties are obtained. In addition, various additives such as a filler, a foaming agent, a flame retardant, a lubricant, an antistatic agent, an antioxidant, a crystal nucleating agent, an ultraviolet absorber, a light stabilizer, a heat stabilizer, a colorant, and a matting agent may be added to the base material 11 as necessary.

[0026] (Picture layer) The pattern layer 12 is, for example, a layer including a pattern printed on the substrate 11 using ink. The ink used to form the pattern layer 12 may include, for example, a binder resin. The binder resin included in the ink used to form the pattern layer 12 may be appropriately selected from, for example, nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc., either alone or modified. In addition, they may be water-based, solvent-based, or emulsion type, and may be one-liquid type or two-liquid type using a hardener. In this embodiment, the ink used to form the pattern layer 12 is preferably a water-based colored ink from the viewpoint of coatability. Examples of methods for hardening the ink used to form the design layer 12 include a method of hardening the ink by irradiation with ultraviolet light, electron beams, etc. Among these, the most common method is a method using a urethane-based ink and hardening it with polyisocyanate.

[0027] In addition to the binder resin described above, the ink used to form the design layer 12 may contain various additives such as pigments, colorants such as dyes, extender pigments, solvents, light stabilizers, etc., which are contained in ordinary inks. Examples of versatile pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica. The method for providing the design layer 12 is not particularly limited, and for example, a typical printing method such as gravure printing, offset printing, screen printing, flexographic printing, or ink jet printing can be used.

[0028] (Transparent resin layer) Polyolefins are preferably used as the material for the transparent resin layer 14, such as polypropylene, polyethylene, polybutene, and various α-olefin copolymers (copolymers of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc.). Among these resins, polypropylene is the most preferable material for the transparent resin layer 14. The transparent resin layer 14 of the present embodiment may be a sheet formed by film formation, or may be a laminate of already formed sheets. The transparent resin layer 14 may be made of, for example, a highly crystalline polypropylene resin.

[0029] It is preferable that polypropylene accounts for 80% by mass or more, and more preferably 90% by mass or more, of the total mass of the transparent resin layer 14. Note that "a transparent resin layer mainly composed of polypropylene" means that polypropylene accounts for 80% by mass or more of the total mass of the transparent resin layer 14. If necessary, various additives such as a heat stabilizer, a flame retardant, an ultraviolet absorber, a light stabilizer, an antiblocking agent, a catalyst scavenger, and, within a range that does not impair the characteristics of this embodiment, a colorant, a light scattering agent, and a gloss adjuster may also be added to the transparent resin layer 14. In general, any combination of the following may be added: heat stabilizers, such as phenol-based, sulfur-based, phosphorus-based, and hydrazine-based agents; flame retardants, such as aluminum hydroxide and magnesium hydroxide; ultraviolet absorbents, such as benzotriazole-based, benzoate-based, benzophenone-based, and triazine-based agents; and light stabilizers, such as hindered amine-based agents.

[0030] The method for producing the transparent resin layer 14 is not particularly limited, and for example, a typical method such as calendar film formation or extrusion film formation can be used. The transparent resin layer 14 may be provided with surface irregularities, so-called embossing, in order to provide design. Examples of methods for providing irregularities include a method of subjecting the transparent resin layer 14 to thermal embossing after extrusion molding, and a method of subjecting the layer to embossing simultaneously with extrusion molding using a cooling roll with irregularities during extrusion molding. More specifically, the irregular pattern (embossed pattern) is directly provided on the transparent resin layer 14, for example, a highly crystalline polypropylene sheet, and the method includes a method of providing an irregular pattern on a polypropylene sheet formed by heat and pressure using an embossing plate having an irregular pattern, and a method of providing an embossment simultaneously with cooling when forming a film using an extruder. Here, it is also possible to fill the recesses of the irregular pattern with colored ink to further improve design. The uneven pattern may be provided if necessary, but may not be provided if unnecessary. Furthermore, one or both surfaces of the transparent resin layer 14 may be activated, for example, by corona treatment, plasma treatment, electron beam treatment, ultraviolet treatment, dichromate treatment, or the like, as necessary.

[0031] (Surface protective layer) The surface protective layer 15 according to this embodiment is a layer provided to impart functions such as weather resistance, scratch resistance, stain resistance, and design properties to the decorative sheet 10. The material constituting the surface protective layer 15 is not particularly limited, and can be appropriately selected from, for example, urethane-based, acrylic-based, acrylic silicone-based, fluorine-based, and epoxy-based resin materials. From the viewpoint of coatability, a water-based ink mainly composed of a urethane polymer is suitable as the material for the surface protective layer 15. Here, "water-based ink mainly composed of a urethane polymer" means that the urethane polymer accounts for 80% by mass or more of the total mass of the water-based ink. In this embodiment, a urethane-based surface protection layer 15 utilizing an isocyanate reaction is preferable from the viewpoints of workability, cost, cohesive strength of the resin itself, and the like.

[0032] In forming the surface protective layer 15, the isocyanate may be appropriately selected from among curing agents such as adducts, biurets, and isocyanurates, which are derivatives of tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (HXDI), trimethylhexamethylene diisocyanate (TMDI), and various prepolymers. In addition, the surface protective layer 15 may contain various additives, such as an ultraviolet absorber, a heat stabilizer, a light stabilizer, an antiblocking agent, a catalyst scavenger, a colorant, a light scattering agent, and a gloss adjuster, as necessary.

[0033] The method for forming the surface protective layer 15 is not particularly limited, and the surface protective layer 15 may be formed by coating the above-mentioned material in a coating liquid form using a conventional method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating, and then curing the liquid using a method suitable for the material, such as thermal curing or ultraviolet curing. Moreover, the surface protective layer 15 may be provided after the pattern layer 12 formed on the base material 11 and the transparent resin layer 14 are bonded together via the adhesive layer 13 .

[0034] (Primer layer) The decorative sheet 10 according to this embodiment may further include a primer layer 16 on the back surface, which is the surface opposite to the surface on which the design layer 12 of the substrate 11 is formed. The primer layer 16 may be formed from the same component as the binder resin contained in the colored ink for forming the design layer 12 .

[0035] The method for forming the primer layer 16 is not particularly limited, and the primer layer 16 may be formed by coating the above-mentioned material in a coating liquid form using a conventional method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating, and then curing the coating using a method suitable for the material, such as thermal curing or ultraviolet curing. In addition, the primer layer 16 may be provided after forming a laminate having the substrate 11, the pattern layer 12, the adhesive layer 13, the transparent resin layer 14, and the surface protective layer 15 in this order, or the primer layer 16 may be provided on the back surface of the substrate 11, and then a laminate having the substrate 11 with the primer layer 16 provided thereon, the pattern layer 12, the adhesive layer 13, the transparent resin layer 14, and the surface protective layer 15 in this order may be formed. In addition, considering that the primer layer 16 will be applied to the back surface of the decorative sheet and will be wound up in web form, inorganic fillers such as silica, alumina, magnesia, titanium oxide, barium sulfate, etc. may be added to the primer layer 16 in order to avoid blocking and to increase adhesion to the adhesive.

[0036] Regarding the thickness of each layer constituting the decorative sheet 10 according to this embodiment, the base material 11 is preferably in the range of 50 μm to 100 μm in consideration of printing workability, cost, etc., the design layer 12 is preferably in the range of 1 μm to 5 μm in consideration of printing workability, cost, etc., the adhesive layer 13 is preferably in the range of 1 μm to 3 μm in consideration of printing workability, transparent resin layer 14 is preferably in the range of 70 μm to 100 μm in consideration of printing workability, transparent resin layer 14 is preferably in the range of 3 μm to 15 ... If the thickness of each layer is less than the respective lower limit value, the function (performance) of each layer may not be obtained. If the thickness of each layer exceeds the respective upper limit value, the function (performance) of each layer is not significantly improved, so it is preferable to set the thickness of each layer to be equal to or less than the respective upper limit value from the viewpoint of production costs. In addition, when the primer layer 16 is provided, the thickness of the primer layer 16 is preferably within the range of 1 μm to 5 μm. If the thickness of the primer layer 16 is within the above numerical range, the function (performance) of the primer layer 16 can be reliably exhibited. The total thickness of the decorative sheet 10 is preferably within the range of 125 μm to 240 μm. Within the above numerical range, printing workability can be easily improved and manufacturing costs can be reduced.

[0037] The peel strength between the adhesive layer 13 and the transparent resin layer 14 in the decorative sheet 10 according to this embodiment is preferably 15 N / inch or more. If the peel strength between the adhesive layer 13 and the transparent resin layer 14 is 15 N / inch or more, when the decorative sheet 10 is produced in a roll form, it is possible to reliably prevent the roll from slipping. It is also preferable that the peel strength between the adhesive layer 13 and the transparent resin layer 14 is 10 N / inch or more after the decorative sheet 10 is exposed to a 40°C, 90% RH environment for 500 hours. If the peel strength between the adhesive layer 13 and the transparent resin layer 14 is 10 N / inch or more after the decorative sheet 10 is exposed to a 40°C, 90% RH environment for 500 hours, excellent durability can be imparted to the decorative sheet 10.

[0038] The peel strength in this embodiment can be determined, for example, by a delamination test described below. <Delamination test> In the decorative sheet 10 in which the adhesive layer 13 has a thickness of 10 μm, a test (interlayer peeling test) is performed to determine whether peeling occurs between the adhesive layer 13 and the transparent resin layer 14.

[0039] After Nichiban cellophane tape is pressed onto the surface of the decorative sheet 10, it is strongly peeled off with a constant force (e.g., 5 N / inch, 10 N / inch, 15 N / inch, 20 N / inch), and the presence or absence of peeling between the adhesive layer 13 and the transparent resin layer 14 is evaluated under a microscope. In this embodiment, the maximum force at which peeling does not occur between the adhesive layer 13 and the transparent resin layer 14 is defined as the "peel strength." It should be noted that the measurement of the peel strength in this embodiment is not limited to the above method, and for example, a T-peel test may be performed between the adhesive layer 13 and the transparent resin layer 14 in accordance with JIS K6854-3:1999 to measure (determine) the peel strength between the adhesive layer 13 and the transparent resin layer 14.

[0040] [Method of manufacturing decorative sheet] A method for producing the decorative sheet 10 according to one embodiment of the present invention will now be briefly described. First, the design layer 12 is formed with a thickness of 1 μm to 5 μm on the substrate 11, which is a polyolefin substrate with a thickness in the range of 50 μm to 100 μm, using a water-based colored ink. Next, on the pattern layer 12, an adhesive layer 13 is formed with a thickness of 1 μm or more and 3 μm or less, the adhesive layer 13 being composed of a polyether-based urethane resin containing at least one polyether glycol selected from polytetramethylene ether glycol (PTMEG), polytetramethylene glycol (PTMG), and pentamethylene glycol (PMG) as at least a resin component, an isocyanate compound having a cyclic structure, and a compound having at least one carboxy group and at least two hydroxyl groups neutralized with triisopanolamine, the hydroxyl value being within the range of 10 mgKOH / g or more and 150 mgKOH / g or less, and the acid value being within the range of 5 mgKOH / g or more and 80 mgKOH / g or less. Next, on the adhesive layer 13, a transparent resin layer 14 containing polypropylene as a main component is formed by extrusion molding to a thickness of 70 μm or more and 100 μm or less. Finally, on the transparent resin layer 14, a surface protection layer 15 is formed with a thickness of 3 μm to 15 μm using a water-based ink containing a urethane polymer as a main component. In this manner, the decorative sheet 10 according to this embodiment is manufactured.

[0041] After forming the design layer 12 and before forming the adhesive layer 13, the surface of the design layer 12 facing the adhesive layer 13 may be subjected to a surface treatment so that the surface has a wetting index of 60 dyne or more. In addition, the colored ink used in the process of forming the pattern layer 12 may contain a binder resin, and a primer layer 16 made of the same component as the binder resin contained in the colored ink and having a film thickness in the range of 1 μm or more and 5 μm or less may be formed on the back surface of the substrate 11, which is the surface opposite to the surface on which the pattern layer 12 is formed.

[0042] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. <Example 1> Part A (100 parts) of polyethylene ether glycol (PEG) with a number average molecular weight of 1,000, part B of tolylene diisocyanate (TDI), part C of dimethylolpropionic acid whose carboxyl group has been neutralized with part D of ethanolamine, and 975 parts of methyl ethyl ketone (MEK) were placed in a reactor and a urethane reaction was carried out at 80°C for 4 hours to obtain a prepolymer having an NCO terminal. Next, 11 parts of sodium dodecylbenzenesulfonate (Na-DBS) was dissolved as an emulsifier in this prepolymer solution, and the solution was gradually added to 1,578 parts of distilled water set at 30° C. with stirring to prepare an emulsion of the prepolymer solution. After that, 106 parts of water was added, the temperature was raised to 40°C, and the mixture was reacted for 1.5 hours to increase the molecular weight. Finally, MEK was removed under reduced pressure to obtain a polyurethane emulsion (polyether-based urethane resin) with a solid content of 30%. The polyurethane emulsion thus obtained had a hydroxyl value of 149.24mgKOH / g and an acid value of 33.4mgKOH / g. The hydroxyl value and acid value of the polyurethane emulsion (polyether-based urethane resin) were adjusted by adjusting the content ratio of each of the above-mentioned alkylene glycol, isocyanate compound having a cyclic structure, COOH and OH group-containing compound, and alkanolamine.

[0043] A wood grain pattern was gravure printed on a polyethylene base film (70 μm thick) with opacity using a two-component urethane ink (V180; manufactured by Toyo Ink Co., Ltd.) to form a pattern layer (3 μm thick). The polyurethane emulsion was applied to the substrate thus obtained to form an adhesive layer (anchor coat layer: thickness 10 μm). The substrate and the transparent polyolefin resin forming the transparent resin layer were dry laminated via this adhesive layer. Furthermore, as a surface protective layer, a two-component cured polyurethane resin layer consisting of an acrylic polyol (a copolymer of methyl methacrylate and 2-hydroxy methacrylate) and a curing agent (a nurate form of hexamethylene diisocyanate) was applied (layer thickness 8 μm) onto the transparent polyolefin resin to obtain the decorative sheet of Example 1.

[0044] <Example 2> The decorative sheet of Example 2 was obtained in the same manner as in Example 1, except that the content ratio of tolylene diisocyanate (TDI) was adjusted to set the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) to 100.68 mg KOH / g and the acid value to 22.56 mg KOH / g.

[0045] <Example 3> The decorative sheet of Example 3 was obtained in the same manner as in Example 1, except that the content ratio of tolylene diisocyanate (TDI) was adjusted to set the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) to 22.47 mg KOH / g and the acid value to 5.03 mg KOH / g.

[0046] <Example 4> The decorative sheet of Example 4 was obtained in the same manner as in Example 1, except that the polyethylene ether glycol (PEG) having a number average molecular weight of 1000 was replaced with polypropylene ether glycol (PPG) having a number average molecular weight of 1000, and the content ratio of tolylene diisocyanate (TDI) was adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.68 mg KOH / g and the acid value was 22.56 mg KOH / g.

[0047] <Example 5> The decorative sheet of Example 5 was obtained in the same manner as in Example 1, except that the polyethylene ether glycol (PEG) having a number average molecular weight of 1000 was replaced with polytetramethylene ether glycol (PTMG) having a number average molecular weight of 1000, and the content ratio of tolylene diisocyanate (TDI) was adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.68 mg KOH / g and the acid value was 22.56 mg KOH / g.

[0048] <Example 6> Tolylene diisocyanate (TDI) and 1,2-bis(isocyanatomethyl)cyclohexa N The decorative sheet of Example 6 was obtained in the same manner as in Example 1, except that the content ratio was adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.00 mg KOH / g and the acid value was 22.41 mg KOH / g.

[0049] <Example 7> The decorative sheet of Example 7 was obtained in the same manner as in Example 1, except that tolylene diisocyanate (TDI) was replaced with 1,3-bis(isocyanatomethyl)cyclohexane (H-XDI) and the content ratio was adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.03 mg KOH / g and the acid value was 22.41 mg KOH / g.

[0050] <Example 8> The decorative sheet of Example 8 was obtained in the same manner as in Example 1, except that ethanolamine was replaced with triisopropanolamine, and the content ratio of tolylene diisocyanate (TDI) and dimethylolpropionic acid was adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.03 mg KOH / g and the acid value was 22.87 mg KOH / g.

[0051] <Example 9> The decorative sheet of Example 9 was obtained in the same manner as in Example 1, except that ethanolamine was replaced with methylethanolamine, and the content ratios of tolylene diisocyanate (TDI) and dimethylolpropionic acid were adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.02 mg KOH / g and the acid value was 24.66 mg KOH / g.

[0052] <Example 10> The decorative sheet of Example 10 was obtained in the same manner as in Example 1, except that ethanolamine was replaced with methyldiethanolamine, the content ratio of tolylene diisocyanate (TDI) was adjusted, the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was set to 100.02 mg KOH / g, and the acid value was set to 21.86 mg KOH / g.

[0053] <Example 11> The decorative sheet of Example 11 was obtained in the same manner as in Example 1, except that ethanolamine was replaced with ethylethanolamine, and the content ratios of tolylene diisocyanate (TDI) and dimethylolpropionic acid were adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.03 mg KOH / g and the acid value was 26.49 mg KOH / g.

[0054] <Example 12> The decorative sheet of Example 12 was obtained in the same manner as in Example 1, except that ethanolamine was replaced with ethyldiethanolamine, and the content ratios of tolylene diisocyanate (TDI) and dimethylolpropionic acid were adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.04 mg KOH / g and the acid value was 23.42 mg KOH / g.

[0055] <Example 13> The decorative sheet of Example 13 was obtained in the same manner as in Example 1, except that dimethylolpropionic acid was replaced with methylolbutyric acid, and the respective content ratios of tolylene diisocyanate (TDI), dimethylolpropionic acid, and ethanolamine were adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.05 mg KOH / g and the acid value was 22.17 mg KOH / g.

[0056] <Comparative Example 1> Polyethylene ether glycol (PEG) with a number average molecular weight of 1000 was replaced with 1,6-hexanediol, and tolylene diisocyanate (TDI) was replaced with 1,2-bis(isocyanatomethyl)cyclohexafluoropropane. N Instead, ethanolamine was replaced with triisopropanolamine, and 1,2-bis(isocyanatomethyl)cyclohexa And The decorative sheet of Comparative Example 1 was obtained in the same manner as in Example 1, except that the content ratios of dimethylolpropionic acid and triisopropanolamine were adjusted to set the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) to 100.02 mg KOH / g and the acid value to 15.48 mg KOH / g.

[0057] <Comparative Example 2> The decorative sheet of Comparative Example 2 was obtained in the same manner as in Example 1, except that tolylene diisocyanate (TDI) was replaced with hexamethylene diisocyanate (HDI), ethanolamine was replaced with triisopropanolamine, and the respective content ratios of hexamethylene diisocyanate (HDI) and dimethylolpropionic acid were adjusted so that the hydroxyl value of the polyurethane emulsion (polyether-based urethane resin) was 100.07 mg KOH / g and the acid value was 21.52 mg KOH / g.

[0058] <Evaluation> The decorative sheets obtained in the above Examples and Comparative Examples were evaluated by measuring the peel strength (N / inch) and the peel strength (N / inch) after 500 hours exposure in a 90% RH environment using the following method. The evaluation results are shown in Tables 1 and 2. <Delamination test> In the decorative sheets of each of the Examples and Comparative Examples in which the adhesive layer had a thickness of 10 μm, a test was carried out to check whether peeling occurred between the adhesive layer and the transparent resin layer (interlayer peeling test).

[0059] After pressing Nichiban cellophane tape onto the surface of the decorative sheet, it was strongly pulled off with a constant force (from 1 N / inch to 10 N / inch, increasing in 1 N / inch increments), and the presence or absence of peeling between the adhesive layer and the transparent resin layer was evaluated under a microscope. In this example, the maximum force at which peeling did not occur between the adhesive layer and the transparent resin layer was defined as "peel strength (N / inch)." The "peel strength (N / inch) after 500 hours of exposure in a 90% RH environment" was determined by placing the decorative sheets of each Example and Comparative Example in a HAST chamber (highly accelerated life testing device), exposing them to a 90% RH environment for 500 hours, and then conducting the above-mentioned interlayer peeling test.

[0060] <Evaluation criteria> ○: Peel strength is 8N / inch or more △: Peel strength is 6N / inch or more and 7N / inch or less ×: Peel strength is 5N / inch or less In this embodiment, if at least one of the "peel strength (N / inch)" and the "peel strength (N / inch) after 500 hours exposure under 90% RH environment" was rated as "x", the overall evaluation was "x". If one of the "peel strength (N / inch)" and the "peel strength (N / inch) after 500 hours exposure under 90% RH environment" was rated as "○" and the other was rated as "△", the overall evaluation was "△". If both of the "peel strength (N / inch)" and the "peel strength (N / inch) after 500 hours exposure under 90% RH environment" were rated as "○", the overall evaluation was "○". If the overall evaluation was "◯" or "Δ", it was determined that the occurrence of delamination was reduced and the product was deemed to have passed.

[0061] [Table 1]

[0062] [Table 2] [Industrial Applicability]

[0063] The present invention can be used as a decorative sheet that requires durability against high temperature and humidity for building exteriors, bathrooms, etc., and can also be used as an indoor sheet such as a surface material for building fixtures or a flooring material. [Explanation of symbols]

[0064] 10 Decorative Sheet 11 Substrate (polyolefin substrate) 12 Picture layer 13 Adhesive layer (anchor coat layer) 14 Transparent resin layer 15 Surface protective layer 16 Primer layer

Claims

1. A decorative sheet comprising, in this order, a polyolefin substrate, a design layer, an anchor coat layer, a transparent resin layer mainly composed of polypropylene, and a top coat layer, The anchor coat layer is made of a polyether-based urethane resin, The polyether-based urethane resin contains, as resin components, at least one polyalkylene glycol selected from polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), and polytetramethylene ether glycol (PTMG) having a number average molecular weight of 200 or more, an isocyanate compound having a cyclic structure, and a compound having at least two hydroxyl groups and at least one carboxy group substituted with an alkanolamine, and is characterized in that the polyether-based urethane resin has a hydroxyl value in the range of 10 mgKOH / g or more and 150 mgKOH / g or less and an acid value in the range of 5 mgKOH / g or more and 80 mgKOH / g or less.

2. 2. The decorative sheet according to claim 1, wherein the isocyanate compound includes either 1,2-bis(isocyanatomethyl)cyclohexane or 1,3-bis(isocyanatomethyl)cyclohexane (H-XDI).

3. 3. The decorative sheet according to claim 1, wherein the alkanolamine comprises at least one alkanolamine selected from the group consisting of triisopanolamine, methylethanolamine, methyldiethanolamine, ethylethanolamine, and ethyldiethanolamine.

4. The thickness of the polyolefin substrate is in the range of 50 μm or more and 100 μm or less, The thickness of the pattern layer is in the range of 1 μm to 5 μm, The thickness of the anchor coat layer is in the range of 1 μm or more and 3 μm or less, The film thickness of the transparent resin layer is in the range of 70 μm or more and 100 μm or less, 4. The decorative sheet according to claim 1, wherein the thickness of the top coat layer is within a range of 3 μm or more and 15 μm or less.

5. 5. The decorative sheet according to claim 1, wherein the design layer is formed from a water-based colored ink.

6. 6. The decorative sheet according to claim 1, wherein the top coat layer is formed from a water-based ink containing a urethane polymer as a main component.

7. The polyolefin substrate further includes a primer layer formed on a back surface opposite to the design layer side, The design layer is formed of a water-based colored ink containing a binder resin, 7. The decorative sheet according to claim 1, wherein the primer layer is formed from the same component as the binder resin contained in the colored ink for forming the design layer.

8. A decorative sheet comprising, in this order, a polyolefin substrate, a design layer, an anchor coat layer, a transparent resin layer mainly composed of polypropylene, and a top coat layer, The anchor coat layer is made of a polyether-based urethane resin, The polyether-based urethane resin is a decorative sheet characterized in that it contains, as resin components, at least one polyalkylene glycol selected from polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), and polytetramethylene ether glycol (PTMG) having a number average molecular weight of 200 or more, an isocyanate compound having a cyclic structure, and a compound having at least two hydroxyl groups and at least one carboxy group substituted with an alkanolamine.

9. A step of forming a pattern layer with a thickness of 1 μm to 5 μm on a polyolefin substrate with a thickness of 50 μm to 100 μm using a water-based colored ink; forming an anchor coat layer on the pattern layer with a thickness of 1 μm to 3 μm, the anchor coat layer being composed of a polyether-based urethane resin containing, as at least a resin component, a polyalkylene glycol having a number average molecular weight of 200 or more, at least one of polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), and polytetramethylene ether glycol (PTMG), an isocyanate compound having a cyclic structure, and a compound having at least one carboxyl group and at least two hydroxyl groups neutralized with triisopanolamine, the hydroxyl value being in the range of 10 mgKOH / g to 150 mgKOH / g and the acid value being in the range of 5 mgKOH / g to 80 mgKOH / g; forming a transparent resin layer mainly composed of polypropylene on the anchor coat layer by extrusion molding to a thickness of 70 μm or more and 100 μm or less; and forming a topcoat layer on the transparent resin layer using a water-based ink containing a urethane polymer as a main component, the topcoat layer having a thickness of 3 μm to 15 μm.

10. The method for producing a decorative sheet according to claim 9, characterized in that the surface of the design layer facing the anchor coat layer is surface-treated so that the surface has a wetting index of 60×10 −5 N or more.

11. The color ink used in the step of forming the design layer contains a binder resin, A method for producing a decorative sheet according to claim 9 or 10, characterized in that a primer layer is formed on the back surface of the polyolefin substrate, which is the surface opposite to the surface on which the pattern layer is formed, the primer layer being composed of the same component as the binder resin contained in the colored ink and having a film thickness in the range of 1 μm to 5 μm.

12. A step of forming a pattern layer with a thickness of 1 μm to 5 μm on a polyolefin substrate with a thickness of 50 μm to 100 μm using a water-based colored ink; forming an anchor coat layer on the pattern layer with a thickness of 1 μm or more and 3 μm or less, the anchor coat layer being composed of a polyether-based urethane resin containing, as at least a resin component, at least one polyalkylene glycol selected from polyethylene ether glycol (PEG), polypropylene ether glycol (PPG), and polytetramethylene ether glycol (PTMG) having a number average molecular weight of 200 or more, an isocyanate compound having a cyclic structure, and a compound having at least one carboxyl group and at least two hydroxyl groups neutralized with triisopanolamine; forming a transparent resin layer mainly composed of polypropylene on the anchor coat layer by extrusion molding to a thickness of 70 μm or more and 100 μm or less; and forming a topcoat layer on the transparent resin layer using a water-based ink containing a urethane polymer as a main component, the topcoat layer having a thickness of 3 μm to 15 μm.

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