Decorative sheet and method for producing the same

Abstract

To provide a decorative sheet excellent in moisture heat resistance and water resistance, and a method for manufacturing the decorative sheet.SOLUTION: A decorative sheet 10 according to an embodiment of the present invention comprises: a base material 1; a pattern layer 2 formed on the base material 1 with an aqueous colored ink; an anchor layer 3 formed on the pattern layer 2, containing a resin having a crosslinked structure formed with an aqueous ink containing a resin emulsion containing a polyether-based urethane having a hydroxyl value of 10 or more as a main component of a resin component and an aqueous isocyanate compound having an NCO content of 5% or more as a curing component, and having a film thickness of 1 μm or more and 3 μm or less; a transparent resin layer 4 formed on the anchor layer 3 with a resin containing polypropylene as a main component; and a topcoat layer 5 formed on the transparent resin layer 4 with an aqueous ink containing a urethane polymer as a main component.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] Generally, when the above laminate is laminated to produce a decorative sheet, 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 this case, delamination may occur between the adhesive layer and the transparent resin layer. In addition, for applications requiring resistance to heat and moisture, acrylic resins that do not have functional groups that cause hydrolysis can be used, but the resulting layer may be hard and brittle, which can lead to cracks when the decorative sheet is processed into a building material, leading to problems such as whitening and moisture penetration. [Prior art documents] [Patent documents]

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

[0005] SUMMARY OF THE PRESENT EMBODIMENT In view of the above problems, an object of the present invention is to provide a decorative sheet which is excellent in water resistance as well as in wet heat resistance, and a method for producing such a decorative sheet. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors discovered that a decorative sheet using a water-based ink containing specific elements in an adhesive layer (also called an anchor layer) can achieve the above-mentioned objectives, and thus arrived at the present invention.

[0007] In order to solve the above problems, a decorative sheet according to one embodiment of the present invention comprises a polyolefin substrate, a pattern layer formed on the polyolefin substrate using an aqueous colored ink, an anchor coat layer on the pattern layer containing a resin having a crosslinked structure formed using an aqueous ink containing, as a resin component, a resin emulsion containing a polyether-based urethane with a hydroxyl value of 10 or more, and as a curing component, an aqueous isocyanate compound with an NCO content of 5% or more, and having a film thickness in the range of 1 μm to 3 μm, a transparent resin layer on the anchor coat layer formed using a resin mainly composed of polypropylene, and a top coat layer on the transparent resin layer formed using an aqueous ink mainly composed of a urethane polymer.

[0008] In addition, in order to solve the above-mentioned problems, a decorative sheet according to one embodiment of the present invention comprises a polyolefin substrate, a pattern layer formed on the polyolefin substrate using an aqueous colored ink, an anchor coat layer on the pattern layer containing a resin having a cross-linked structure formed using an aqueous ink containing, as a resin component, a resin emulsion containing a polyether-based urethane with an acid value of 10 or more, and as a curing component, an epoxy compound with an epoxy equivalent of 50 or more, and having a film thickness in the range of 1 μm or more and 3 μm or less, a transparent resin layer on the anchor coat layer formed using a resin mainly composed of polypropylene, and a top coat layer on the transparent resin layer formed using an aqueous ink mainly composed of a urethane polymer. Effect of the Invention

[0009] According to one aspect of the present invention, there is provided a decorative sheet having excellent water resistance as well as moist heat resistance, and a method for producing the decorative sheet. [Brief description of the drawings]

[0010] [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

[0011] An 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.

[0012] [Overall composition of decorative sheet] 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 1, a design layer 2 formed on the substrate 1, an anchor layer (anchor coat layer) 3 formed on the design layer 2, a transparent resin layer 4 formed on the anchor layer 3, and a top coat layer 5 formed on the transparent resin layer 4. Hereinafter, as this embodiment, a decorative sheet 10 in which the transparent resin layer 4 is bonded via the anchor layer 3 to the substrate 1 on which the design layer 2 is printed, and further the top coat layer 5 is provided, will be described with reference to Fig. 1.

[0013] (Anchor layer) The anchor layer 3 is a layer containing a resin having a crosslinked structure formed by an aqueous ink containing a resin component and a curing component. Here, "aqueous ink" refers to a printing ink that does not use petroleum-based solvents and uses a water-soluble resin as a vehicle. The use of aqueous ink has the advantage of improving safety in the production process. In addition, since aqueous ink does not use solvents, the use of aqueous ink has the advantage of being able to provide an environmentally friendly decorative sheet, a so-called eco-sheet.

[0014] The main component of the resin component contained in the aqueous ink used to form the anchor layer 3 (hereinafter also referred to as the aqueous ink for forming the anchor layer) is a resin emulsion containing a polyether-based urethane having a hydroxyl value (mgKOH / g) of 10 or more, or a resin emulsion containing a polyether-based urethane having an acid value (mgKOH / g) of 10 or more. Here, the "main component" refers to a component that accounts for 50 mass% or more of the total mass of the resin components contained in the aqueous ink. A hydrophilic site of the polyether-based urethane having a hydroxyl value or an acid value of 10 or more can be reacted with a curing component described later to form a resin having a crosslinked structure. This increases the hardness of the anchor layer 3, reduces interlayer peeling that occurs between the anchor layer 3 and the transparent resin layer 4, and provides the anchor layer 3 with excellent moist heat resistance and excellent water resistance. In addition, in conventional anchor layers (adhesive layers), the resin component always has hydrophilic sites, and it is thought that various reactions take place starting from these hydrophilic sites, resulting in a decrease in moist heat resistance or water resistance.

[0015] In this embodiment, there is no upper limit to the hydroxyl value of the polyether-based urethane, but in consideration of handling of the water-based ink for forming the anchor layer, it is preferably 100 or less. In this embodiment, there is no upper limit to the acid value of the polyether-based urethane, but in consideration of the handling of the water-based ink for forming the anchor layer, it is preferably 60 or less. In this embodiment, the molecular weight (Mw) of the polyether urethane has no upper limit, but considering the handling of the aqueous ink for forming the anchor layer, it is preferably 100,000 or less. In this embodiment, the molecular weight (Mw) of the polyether urethane has no lower limit, but considering the handling of the aqueous ink for forming the anchor layer, it is preferably 50,000 or more.

[0016] The curing component contained in the aqueous ink for forming the anchor layer is an aqueous isocyanate compound having an NCO content of 5% or more when a resin emulsion containing a polyether-based urethane having a hydroxyl value of 10 or more is used as the above-mentioned resin component. If the NCO content of the aqueous isocyanate compound is 5% or more, the hydrophilic site of the above-mentioned polyether-based urethane and the aqueous isocyanate compound react sufficiently, and the efficiency of forming a resin having a crosslinked structure can be increased.

[0017] Furthermore, when a resin emulsion containing a polyether-based urethane having an acid value of 10 or more is used as the above-mentioned resin component, the curing component contained in the aqueous ink for forming the anchor layer is an epoxy compound having an epoxy equivalent of 50 or more. Similarly, an epoxy compound having an epoxy equivalent of 50 or more can sufficiently react with the hydrophilic site of the above-mentioned polyether-based urethane and the epoxy compound, thereby increasing the efficiency of forming a resin having a crosslinked structure. In this embodiment, there is no upper limit to the NCO content of the aqueous isocyanate compound, but in consideration of handling of the aqueous ink for forming the anchor layer, it is preferably 20% or less. In this embodiment, there is no upper limit to the epoxy equivalent of the epoxy compound, but in consideration of handling of the water-based ink for forming the anchor layer, it is preferably 600 or less.

[0018] Examples of the aqueous isocyanate compound include those manufactured by DIC Corporation under the trade names "BURNOCK DNW-5000", "BURNOCK DNW-5010", "BURNOCK DNW-5100", "BURNOCK DNW-5200", "BURNOCK DNW-5500", and "BURNOCK DNW-6000"; those manufactured by Nippon Polyurethane Industry Co., Ltd. under the trade names "AQUANATE 100", "AQUANATE 105", "AQUANATE 110", "AQUANATE 120", "AQUANATE 130", "AQUANATE 200", and "AQUANATE 210"; and those manufactured by Mitsui Polyurethane Co., Ltd. Examples of such polyurethanes include trade names "Takenate WD-220", "Takenate WD-240", "Takenate WD-720", "Takenate WD-725", "Takenate WD-726", "Takenate WD-730", "Takenate WB-700", "Takenate WB-720", and "Takenate WB-920" manufactured by Chemical Polyurethanes Co., Ltd.; and trade names "Elastron BN-04", "Elastron BN-11", "Elastron BN-27", "Elastron BN-69", and "Elastron BN-77" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0019] Examples of epoxy resins include various compounds containing two or more epoxy groups in the molecule, such as bisphenol-type epoxy resins, aliphatic epoxy resins, aromatic epoxy resins, halogenated bisphenol-type epoxy resins, and biphenyl-type epoxy resins.

[0020] The content of the resin emulsion containing polyether-based urethane in the aqueous ink for forming an anchor layer is preferably 15% by mass or more and 35% by mass or less, and more preferably 21% by mass or more and 35% by mass or less, of the total mass of the aqueous ink for forming an anchor layer. In other words, the anchor layer 3 is preferably composed of a resin containing 15% by mass or more and 35% by mass or less of polyether-based urethane, and more preferably 21% by mass or more and 35% by mass or less, of the total mass of the anchor layer 3.

[0021] In addition, the ratio of the number of functional groups of the resin emulsion containing polyether-based urethane in the aqueous ink for forming the anchor layer to the number of functional groups of the curing component (the number of functional groups of the curing component / the number of functional groups of the resin emulsion) is preferably within the range of 1.0 to 1.5. If it is within the above numerical range, the amount of the curing component that does not contribute to the crosslinking reaction can be reduced. The thickness of the anchor layer 3 is within the range of 1 μm or more and 3 μm or less. If the thickness of the anchor layer 3 is 1 μm or more, the pattern layer 2 and the transparent resin layer 4 can be sufficiently adhered to each other. Furthermore, if the thickness of the anchor layer 3 is 3 μm or less, coating unevenness that occurs during coating of the anchor layer 3 can be reduced.

[0022] In this embodiment, the anchor layer forming water-based ink may further contain, as a subcomponent, a resin emulsion containing a polycarbonate-based urethane having a hydroxyl value (mgKOH / g) of 10 or more. Here, the "subcomponent" refers to a component whose proportion of the mass of the total resin components contained in the water-based ink is less than 50% by mass. In other words, the content of the resin emulsion containing a polycarbonate-based urethane is preferably less than the content of the resin emulsion containing the polyether-based urethane described above. If the anchor layer forming water-based ink further contains the resin emulsion containing the polycarbonate-based urethane described above, the hydrophilic site of the polycarbonate-based urethane can be reacted with the curing component described above to form a resin having a crosslinked structure. This further increases the hardness of the anchor layer 3, and the anchor layer 3 is provided with even better moist heat resistance and even better water resistance. Also, if the anchor layer forming water-based ink further contains the resin emulsion containing the polycarbonate-based urethane described above, the anchor layer 3 is provided with excellent heat resistance.

[0023] In this embodiment, there is no upper limit to the hydroxyl value of the polycarbonate-based urethane, but in consideration of the handling of the water-based ink for forming the anchor layer, it is preferably 30 or less. In this embodiment, there is no upper limit to the molecular weight (Mw) of the polycarbonate-based urethane, but in consideration of the handling of the aqueous ink for forming the anchor layer, it is preferably 100,000 or less. In addition, the ratio of the number of functional groups of the resin emulsion containing polycarbonate-based urethane in the aqueous ink for forming the anchor layer to the number of functional groups of the curing component (the number of functional groups of the curing component / the number of functional groups of the resin emulsion) is preferably within the range of 1.0 to 1.5. Within the above numerical range, the amount of the curing component that does not contribute to the crosslinking reaction can be reduced.

[0024] In this embodiment, the aqueous ink for forming an anchor layer may contain a resin emulsion containing a polyether-based urethane having a hydroxyl value of 10 or more, and a resin emulsion containing a polycarbonate-based urethane having a hydroxyl value of 10 or more, in which case the content of the resin emulsion containing polyether-based urethane may be greater than the content of the resin emulsion containing polycarbonate-based urethane. By using the aqueous ink for forming an anchor layer prepared in this manner, an anchor layer 3 containing a polyether-based urethane component and a polycarbonate-based urethane component and having excellent moist heat resistance and water resistance can be formed.

[0025] The ratio of the content of the resin emulsion containing polyether-based urethane (main component) to the content of the resin emulsion containing polycarbonate-based urethane (secondary component) (content of the resin emulsion containing polyether-based urethane: content of the resin emulsion containing polycarbonate-based urethane) is preferably within the range of 100:0 to 70:30. If the content of the resin emulsion containing polyether-based urethane is within the above numerical range, a crosslinked structure is effectively formed, the hardness of the anchor layer 3 is increased, and the anchor layer 3 is provided with excellent moist heat resistance and excellent water resistance. The anchor layer 3 is formed by applying the above-mentioned water-based ink using a common application method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating.

[0026] (base material) The resin constituting the substrate 1, i.e., the resin component, is preferably polyolefin or polyester, and can be arbitrarily selected from existing materials such as polyethylene, polypropylene, polybutylene, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Among them, a polyolefin substrate, i.e., a substrate containing polyolefin, or a layer composed of a substrate containing only polyolefin, is preferable as the substrate 1. Polyethylene is the most preferable polyolefin constituting the substrate 1. By making the substrate 1 a layer composed of a polyolefin substrate, it is possible to reduce the generation of harmful gases, etc., at the time of disposal. In addition, by making the substrate 1 a layer composed of a substrate containing polyethylene, or a substrate containing only polyethylene, it is possible to further reduce the generation of harmful gases, etc., at the time of disposal. The substrate 1 may be subjected to a surface treatment such as corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet treatment, or dichromate treatment in order to improve adhesion with adjacent layers. If the base material 1 is made of polyolefin, the adhesion to the pattern layer 2 described below is ensured.

[0027] (Picture layer) The pattern layer 2 is, for example, a layer including a pattern printed on the substrate 1 using a water-based colored ink. The ink used to form the pattern layer 2 may include, for example, a binder resin. The binder resin included in the ink used to form the pattern layer 2 may be selected from, for example, nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc., either alone or modified. They may be water-based, solvent-based, or emulsion type, and may be one-liquid type or two-liquid type using a hardener. In addition, as the ink used to form the pattern layer 2, water-based colored ink is most preferable, taking into consideration the adhesiveness to the anchor layer 3 and the adhesiveness to the substrate 1.

[0028] Examples of methods for curing the ink used to form the design layer 2 include a method of curing 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 curing it with polyisocyanate. In addition to the binder resin described above, the ink used to form the design layer 2 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.

[0029] The method for providing the design layer 2 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. The wettability index of the surface of the design layer 2 facing the anchor layer 3 is preferably 60 dyne or more. If the wettability index of the surface of the design layer 2 facing the anchor layer 3 is 60 dyne or more, the water-based ink for forming the anchor layer will be more easily adhered to the design layer 2, the adhesion between the design layer 2 and the anchor layer 3 will be improved, and the surface flatness of the anchor layer 3 will also be improved. The wettability index of the surface of the design layer 2 can be confirmed using a so-called "wetting reagent."

[0030] (Transparent resin layer) The decorative sheet 10 according to this embodiment comprises a transparent resin layer 4 and a topcoat layer 5 formed on one side of the transparent resin layer 4, that is, on the upper layer of the transparent resin layer 4. The transparent resin layer 4 is a layer formed on the anchor layer 3 from a resin containing polypropylene as a main component. In other words, the transparent resin layer 4 is a layer formed without using a solvent. Here, the term "main component" means that the mass of polypropylene in the total mass of the transparent resin layer 4 is 50 mass% or more.

[0031] Polyolefin is preferably used as the material for the transparent resin layer 4, and examples of materials other than the above-mentioned polypropylene include polyethylene, polybutene, and various α-olefin copolymers (copolymers of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc.). The transparent resin layer 4 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.

[0032] The method for producing the transparent resin layer 4 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 4 may be provided with surface irregularities, so-called embossing, in order to provide a design. Examples of methods for providing the irregularities include a method of subjecting the transparent resin layer 4 to thermal embossing after extrusion molding, and a method of subjecting the layer to embossing simultaneously with extrusion molding using a cooling roll provided with irregularities during extrusion molding.

[0033] In this embodiment, the peel strength between the anchor layer 3 and the transparent resin layer 4 is preferably 15 N / inch or more. If the peel strength between the anchor layer 3 and the transparent resin layer 4 is 15 N / inch or more, the adhesive strength between the anchor layer 3 and the transparent resin layer 4 is sufficient. In this embodiment, the peel strength between the anchor layer 3 and the transparent resin layer 4 of the decorative sheet after exposure to an environment of 105°C and 100% RH for 24 hours is preferably 5 N / inch or more. If the peel strength between the anchor layer 3 and the transparent resin layer 4 of the decorative sheet after exposure to an environment of 105°C and 100% RH for 24 hours is 5 N / inch or more, the adhesive strength between the anchor layer 3 and the transparent resin layer 4 is sufficient.

[0034] The wetting index of the surface of the transparent resin layer 4 facing the topcoat layer 5 is preferably 60 dyne or more. If the surface of the transparent resin layer 4 facing the topcoat layer 5 has a wetting index of 60 dyne or more, the ink for forming the topcoat layer will be more easily attached to the transparent resin layer 4, the adhesion between the transparent resin layer 4 and the topcoat layer 5 will be improved, and the surface flatness of the topcoat layer 5 will also be improved. The wetting index of the surface of the transparent resin layer 4 can be confirmed using a so-called "wetting reagent."

[0035] (Topcoat layer) The topcoat layer 5 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 topcoat layer 5 is not particularly limited, and may be appropriately selected from, for example, urethane-based, acrylic-based, acrylic silicone-based, fluorine-based, epoxy-based, and other resin materials. Among them, the topcoat layer 5 is preferably a layer formed from a water-based ink containing a urethane polymer as a main component. Here, the term "main component" means that the mass of the urethane polymer in the total mass of the topcoat layer 5 is 50% by mass or more.

[0036] The topcoat layer 5 may contain various additives, such as an ultraviolet absorbing agent, a heat stabilizer, a light stabilizer, an antiblocking agent, a catalyst scavenger, a colorant, a light scattering agent, and a gloss adjusting agent, as required. Generally, a filler is added to the topcoat layer 5 as a gloss regulator, and for example, any of organic materials such as acrylic beads and silicone beads, and inorganic materials such as alumina and silica can be used, but silica (silica filler) made of an inorganic material is preferred in terms of scratch resistance. Silica exhibits good scratch resistance compared to other materials, which is thought to be due to the fact that silica has an appropriate hardness.

[0037] The silica preferably has a spherical shape and a pore volume of 1 mL / g or more. The larger the pore volume of the silica (specifically, 1 mL / g or more), the more excellent the scratch resistance. This is believed to be due to the influence of the binder resin component impregnating the silica pores. In addition, the silica with a large pore volume has a large function of reducing gloss and is also effective in reducing the required amount of gloss regulator. The content of the gloss regulator is preferably in the range of 1 mass% to 30 mass% and more preferably in the range of 2 mass% to 20 mass% with respect to the total mass of the top coat layer 5. That is, in this embodiment, when silica (silica filler) with a pore volume of 1 mL / g or more is added as the gloss regulator, the content of the silica is preferably in the range of 1 mass% to 30 mass% and more preferably in the range of 2 mass% to 20 mass% with respect to the total mass of the top coat layer 5.

[0038] Moreover, the silica is preferably spherical in shape and has an oil supply amount of, for example, 100mL to 200mL / 100g. Silica tends to have excellent scratch resistance when it has a large oil absorption amount (specifically, 100mL to 200mL / 100g), which is thought to be influenced by the increased affinity between the binder resin component and the silica surface. Furthermore, silica with a large oil supply amount has a large function of reducing gloss and is also effective in reducing the required amount of gloss regulator. Therefore, in this embodiment, when silica (silica filler) with an oil supply amount of 100mL to 200mL / 100g is added as a gloss regulator, the content of the silica is preferably in the range of 1 mass% to 30 mass% and more preferably in the range of 2 mass% to 20 mass% with respect to the total mass of the top coat layer 5.

[0039] In addition, an ultraviolet absorber or a light stabilizer can be added to the top coat layer 5 as a weathering agent, if necessary. The ultraviolet absorber is, for example, a benzotriazole-based, benzoate-based, benzophenone-based, or triazine-based agent, and the light stabilizer is, for example, a hindered amine-based agent, and is generally added in any combination. That is, the top coat layer 5 may contain an ultraviolet absorber having a triazine skeleton and a light stabilizer having a NOR skeleton as a weathering agent. The content of the ultraviolet absorber having a triazine skeleton in the top coat layer 5 is preferably in the range of 1% by mass to 10% by mass, and more preferably in the range of 3% by mass to 6% by mass, based on the total mass of the top coat layer 5. In addition, the content of the light stabilizer having a NOR skeleton in the top coat layer 5 is preferably in the range of 1% by mass to 10% by mass, and more preferably in the range of 3% by mass to 6% by mass, based on the total mass of the top coat layer 5. When the content of the ultraviolet absorber having a triazine skeleton and the content of the light stabilizer having a NOR skeleton are within the above numerical ranges, the weather resistance can be further improved while maintaining the basic functions of the top coat layer 5, such as scratch resistance and contamination resistance.

[0040] In the top coat layer 5, the content of the ultraviolet absorber having a triazine skeleton is preferably higher than the content of the light stabilizer having a NOR skeleton, and is preferably within a range of 1.5 to 3 times. If the content of the ultraviolet absorber having a triazine skeleton is within the above numerical range, the weather resistance can be further improved while maintaining the basic functions of the top coat layer 5 such as scratch resistance and stain resistance. Furthermore, a polyethylene wax can be added as a lubricant to the top coat layer 5 as needed. Here, "polyethylene wax" refers to low molecular weight polyethylene having a molecular weight of tens of thousands or less. Also, "wax" refers to "(1) something that is solid or semi-solid at room temperature, has a melting point of 40°C or higher, and (2) melts when heated without decomposing, and has low viscosity."

[0041] Examples of the polyethylene wax that can be used include the "Sun Wax" series manufactured by Sanyo Chemical Industries, Ltd. and the "Hi Wax" series manufactured by Mitsui Chemicals, Inc. The content of the polyethylene wax in the top coat layer 5 is preferably within a range of 1% by mass to 10% by mass, and more preferably within a range of 3% by mass to 6% by mass, based on the total mass of the top coat layer 5. If the content of the polyethylene wax is within the above numerical range, the basic functions of the top coat layer 5, such as scratch resistance, can be maintained while the stain resistance can be further improved. It is preferable that the gloss change of the top coat layer 5 before and after 500 hours of exposure in an environment of 85°C and 85% RH is within 5%. If the gloss change of the top coat layer 5 before and after 500 hours of exposure in an environment of 85°C and 85% RH is within 5%, the weather resistance of the top coat layer 5 is sufficient.

[0042] The method for forming the topcoat layer 5 is not particularly limited, and the topcoat layer 5 may be formed by coating the above-mentioned materials in a coating liquid 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. Moreover, the topcoat layer 5 may be provided after the design layer 2 formed on the substrate 1 and the transparent resin layer 4 are bonded together via the anchor layer 3 .

[0043] (Primer layer) The decorative sheet 10 according to this embodiment may have a primer layer 6 on the back surface, which is the surface opposite to the surface on which the design layer 2 of the substrate 1 is formed. The primer layer 6 is a layer formed from the same component as the binder resin contained in the colored ink used to form the design layer 2, and has a film thickness in the range of 1 μm to 5 μm. The binder resin contained in the colored ink used to form the design layer 2 contains a component that easily adheres to the substrate 1, so if the primer layer 6 is formed from the same component as the binder resin contained in the colored ink, the primer layer 6 will have high adhesion to the substrate 1, just like the design layer 2.

[0044] Furthermore, if the thickness of the primer layer 6 is 1 μm or more, the primer function inherent to the primer layer 6 (for example, easy adhesion and flat surface smoothness) can be exhibited. If the thickness of the primer layer 6 is 5 μm or less, coating unevenness occurring during coating of the primer layer 6 can be reduced. The material used to form the primer layer 6 may be, for example, a urethane resin, an acrylic resin, a polyester resin, a vinyl chloride / vinyl acetate copolymer, a chlorinated polypropylene resin, a chlorinated polyethylene resin, or the like.

[0045] Furthermore, the primer layer 6 may be, for example, a urethane resin-based primer layer made of an acrylic modified urethane resin (acrylic urethane-based resin), a primer layer made of a urethane-cellulose-based resin (for example, a resin obtained by adding hexamethylene diisocyanate to a mixture of urethane and soluble cellulose), or a resin-based primer layer made of a block copolymer of acrylic and urethane. In order to prevent blocking that may occur when the primer layer 6 is wound up in web form, the primer layer 6 may contain an inorganic filler such as silica, alumina, magnesia, titanium oxide, barium sulfate, or the like.

[0046] The following describes the thickness of each layer constituting the decorative sheet 10 of this embodiment. Considering printing workability, cost, and the like, the thickness of the substrate 1 is preferably in the range of 20 μm to 150 μm, and more preferably in the range of 50 μm to 100 μm. Similarly, in consideration of printing workability, costs, etc., the film thickness of the design layer 2 is preferably in the range of 0.5 μm to 10 μm, more preferably in the range of 1 μm to 5 μm. Similarly, in consideration of printing workability, costs, and the like, the film thickness of the transparent resin layer 4 is preferably in the range of 20 μm or more and 200 μm or less, and more preferably in the range of 70 μm or more and 100 μm or less.

[0047] Similarly, in consideration of printability, cost, and the like, the film thickness of the topcoat layer 5 is preferably in the range of 3 μm to 20 μm, and more preferably in the range of 3 μm to 15 μm. Additionally, the total thickness of the decorative sheet 10 is preferably within the range of 45 μm to 250 μm. If the total thickness of the decorative sheet 10 is less than 45 μm, the strength of the entire decorative sheet 10 is insufficient, and for example, when the decorative sheet 10 is manufactured in-line, the decorative sheet 10 may be damaged during manufacturing. If the total thickness of the decorative sheet 10 exceeds 250 μm, the flexibility of the entire decorative sheet 10 decreases, and the decorative sheet 10 may crack or whiten.

[0048] [Manufacturing method of decorative sheet] A method for producing the decorative sheet 10 according to this embodiment will now be briefly described. First, the design layer 2 is formed on the base material 1 using a water-based colored ink. Next, an anchor coat layer 3 is formed on the design layer 2 to a thickness of 1 μm or more and 3 μm or less using a water-based ink containing, as the main resin component, a resin emulsion containing a polyether-based urethane having a hydroxyl value of 10 or more, and as the curing component, a water-based isocyanate compound having an NCO content of 5% or more. Alternatively, an anchor coat layer 3 is formed on the design layer 2 to a thickness of 1 μm or more and 3 μm or less using a water-based ink containing, as the main resin component, a resin emulsion containing a polyether-based urethane having an acid value of 10 or more, and as the curing component, an epoxy compound having an epoxy equivalent of 50 or more.

[0049] Next, a transparent resin layer 4 containing polypropylene as a main component is formed on the anchor coat layer 3 by extrusion molding. Finally, a topcoat layer 5 is formed on the transparent resin layer 4 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. In each step of forming the pattern layer 2 and the transparent resin layer 4, the surfaces of the pattern layer 2 and the transparent resin layer 4 may be treated so that the wetting index of each surface is 60 dyne or more. In addition, a primer layer 6 made of the same component as the binder resin contained in the colored ink used to form the pattern layer 2 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 1, which is the surface opposite to the surface on which the pattern layer 2 is formed.

[0050] 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.

[0051] <Example 1> As the substrate 1, a substrate having a thickness of 70 μm and formed by extrusion molding of polypropylene resin was used. Next, on the substrate 1, a design layer 2 was formed to a thickness of 2 μm using a colored ink containing a two-component urethane ink (V180; manufactured by Toyo Ink Co., Ltd.) as a binder. Next, the anchor layer 3 was formed on the pattern layer 2. The anchor layer 3 was formed by applying an aqueous ink containing a polyether-based urethane resin emulsion (product name: w5661; manufactured by Mitsui Chemicals, Inc.) having a hydroxyl value of 10 or more and an acid value of 10 or more as a main component and an aqueous isocyanate compound (product name: WT-30-100; manufactured by Asahi Kasei Corporation) having an NCO content of 16.5% as a curing component to a thickness of 2 μm by gravure coating, so that the film thickness after drying was 1 μm. In the aqueous ink for forming the anchor layer 3, the content of the polyether-based urethane resin emulsion was 25% by mass, and the content of the aqueous isocyanate compound was 30% by mass.

[0052] Next, a transparent resin layer 4 was formed on the anchor layer 3. The transparent resin layer 4 was formed by extrusion lamination of polypropylene resin so as to have a thickness of 70 μm. Furthermore, a topcoat layer 5 was provided on the transparent resin layer 4. The topcoat layer 5 was formed to a thickness of 7 μm by a gravure coating method using a water-based ink containing a urethane polymer (product name: w6010; manufactured by Mitsui Chemicals, Inc.) as the main component. Finally, a primer layer 6 made of the same component as the binder used in the design layer 2 was formed on the back surface of the substrate 1 to a thickness of 2 μm. In this manner, the decorative sheet of Example 1 was produced.

[0053] <Example 2> A decorative sheet of Example 2 was produced in the same manner as in Example 1, except that the thickness of the anchor layer 3 was set to 3 μm. <Example 3> A decorative sheet of Example 3 was produced in the same manner as in Example 1, except that the curing component was an epoxy compound having an epoxy equivalent of 50 or more (product name: EX830).

[0054] <Example 4> A decorative sheet of Example 4 was produced in the same manner as in Example 1, except that a resin emulsion containing polycarbonate-based urethane (product name: HA-207) was further added. In the water-based ink (anchor layer 3), the component ratio (by mass) of the polyether-based urethane resin emulsion (main component) to the resin emulsion containing polycarbonate-based urethane (secondary component) was 70:30. <Example 5> A decorative sheet of Example 5 was produced in the same manner as in Example 4, except that the curing component was an epoxy compound having an epoxy equivalent of 50 or more (product name: EX830).

[0055] <Comparative Example 1> A decorative sheet of Comparative Example 1 was produced in the same manner as in Example 1, except that the polyether-based urethane resin emulsion was a polyether-based urethane resin emulsion (product name: HA-15) with a hydroxyl value of 0 (none) and an acid value of 0 (none). <Comparative Example 2> A decorative sheet of Comparative Example 2 was produced in the same manner as Comparative Example 1, except that the curing component was an epoxy compound having an epoxy equivalent of 50 or more (product name: EX830). <Comparative Example 3> A decorative sheet of Comparative Example 3 was produced in the same manner as in Example 1, except that no curing component was added.

[0056] <Comparative Example 4> A decorative sheet of Comparative Example 4 was produced in the same manner as in Example 1, except that the thickness of the anchor layer 3 was set to 0.8 μm. <Comparative Example 5> A decorative sheet of Comparative Example 5 was produced in the same manner as in Example 1, except that the thickness of the anchor layer 3 was set to 3.2 μm.

[0057] <Evaluation> The decorative sheets obtained in the above Examples and Comparative Examples were evaluated for moist heat resistance and water resistance by the following methods. The evaluation results are shown in Table 1.

[0058] (a) Moisture and heat resistance The decorative sheet was subjected to a moist heat treatment in a HAST chamber (105°C, 100% RH, 24 hours), after which the T-peel strength between the anchor layer and the transparent resin layer was measured (sample width: 25 mm, tensile speed: 50 mm / min). <Evaluation criteria> Passed: No change in peel strength before and after the heat and moisture resistance test Failed: Peel strength decreased after heat and moisture resistance test

[0059] (b) Water resistance Water resistance was evaluated by immersing the decorative sheet in boiling water for 1 hour, and then measuring the T-peel strength between the anchor layer and the transparent resin layer (sample width: 25 mm, tensile speed: 50 mm / min). <Evaluation criteria> Pass: Peel strength after test is 17N / inch or more Fail: Peel strength after test is less than 17N / inch

[0060] [Table 1]

[0061] The decorative sheet shown in this embodiment comprises an anchor layer 3 which contains a resin having a cross-linked structure formed from an aqueous ink containing, as the main resin component, a resin emulsion containing a polyether-based urethane with a hydroxyl value of 10 or more, and as the curing component, an aqueous isocyanate compound with an NCO content of 5% or more, and which is a layer with a thickness of 1 μm or more and 3 μm or less. This reduces interlayer delamination that occurs between the anchor layer 3 and the transparent resin layer 4, and provides excellent both moist heat resistance and water resistance. In addition, by making the anchor layer 3 a layer containing a resin having a cross-linked structure formed by an aqueous ink containing, as the main resin component, a resin emulsion including a polyether-based urethane with an acid value of 10 or more, and as the curing component, an epoxy compound with an epoxy equivalent of 50 or more, and having a film thickness of 1 μm or more and 3 μm or less, interlayer delamination that occurs between the anchor layer 3 and the transparent resin layer 4 is reduced, and both moist heat resistance and water resistance are excellent. [Industrial Applicability]

[0062] 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]

[0063] 10 Decorative Sheet 1 Base material 2. Picture layer 3 Anchor Layer 4 Transparent resin layer 5 Topcoat layer 6 Primer layer

Claims

1. A polyolefin substrate; A design layer formed on the polyolefin substrate using a water-based colored ink; an anchor coat layer on the design layer, the anchor coat layer including a resin having a crosslinked structure formed by an aqueous ink containing, as a resin component, a resin emulsion containing a polyether-based urethane having a hydroxyl value of 10 or more, and a resin emulsion containing a polycarbonate-based urethane having a hydroxyl value of 10 or more, and, as a curing component, an aqueous isocyanate compound having an NCO content of 5% or more, and a thickness of 1 μm or more and 3 μm or less; a transparent resin layer formed on the anchor coat layer using a resin mainly composed of polypropylene; A decorative sheet comprising a topcoat layer formed on the transparent resin layer using a water-based ink containing a urethane polymer as a main component.

2. A polyolefin substrate; A design layer formed on the polyolefin substrate using a water-based colored ink; an anchor coat layer on the design layer, the anchor coat layer including a resin having a crosslinked structure formed by an aqueous ink containing, as a resin component, a resin emulsion containing a polyether-based urethane having an acid value of 10 or more, and a resin emulsion containing a polycarbonate-based urethane, and, as a curing component, an epoxy compound having an epoxy equivalent of 50 or more, and a thickness of 1 μm or more and 3 μm or less; a transparent resin layer formed on the anchor coat layer using a resin mainly composed of polypropylene; A decorative sheet comprising a topcoat layer formed on the transparent resin layer using a water-based ink containing a urethane polymer as a main component.

3. 3. The decorative sheet according to claim 1, wherein the surface of said design layer facing said anchor coat layer has a wetting index of 60 dyne or more.

4. 4. The decorative sheet according to claim 1, wherein a peel strength between the anchor coat layer and the transparent resin layer is 15 N / inch or more.

5. 5. The decorative sheet according to claim 1, wherein the peel strength between the anchor coat layer and the transparent resin layer after exposure of the decorative sheet to an environment of 105° C. and 100% RH for 24 hours is 5 N / inch or more.

6. The top coat layer contains a silica filler as a gloss adjuster, 6. The decorative sheet according to claim 1, wherein the silica filler has a pore volume of 1 mL / g or more, or an oil absorption amount within the range of 100 mL / 100 g to 200 mL / 100 g.

7. 6. The decorative sheet according to claim 1, wherein the top coat layer contains acrylic beads or silicone beads as a gloss adjusting agent.

8. 8. The decorative sheet according to claim 1, wherein the top coat layer contains, as weather resistance agents, an ultraviolet absorber having a triazine skeleton and a light stabilizer having a NOR type skeleton.

9. 9. The decorative sheet according to claim 1, wherein the top coat layer contains a polyethylene wax as a lubricant.

10. 10. The decorative sheet according to claim 1, wherein the transparent resin layer has a surface facing the top coat layer with a wetting index of 60 dynes or more.

11. 11. The decorative sheet according to claim 1, wherein the change in gloss of the top coat layer before and after exposure for 500 hours in an environment of 85°C and 85% RH is within 5%.

12. A decorative sheet as described in any one of claims 1 to 11, characterized in that a primer layer is provided on the back surface of the polyolefin substrate opposite 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.

13. 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 film thickness of the transparent resin layer is in the range of 70 μm or more and 100 μm or less, 13. 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.

14. A decorative sheet as described in claim 1, characterized in that the content of the resin emulsion containing the polyether-based urethane is greater than the content of the resin emulsion containing the polycarbonate-based urethane.

15. A decorative sheet as described in claim 1, characterized in that the content of the resin emulsion containing the polyether-based urethane is 70% or more of the total content of the resin emulsion containing the polyether-based urethane and the resin emulsion containing the polycarbonate-based urethane.

16. A method for producing a decorative sheet, comprising the steps of: forming a pattern layer on a polyolefin substrate using an aqueous colored ink; forming an anchor coat layer on this pattern layer to a thickness of 1 μm or more and 3 μm or less using an aqueous ink containing, as resin components, a resin emulsion containing a polyether-based urethane having a hydroxyl value of 10 or more and a resin emulsion containing a polycarbonate-based urethane having a hydroxyl value of 10 or more, and, as a curing component, an aqueous isocyanate compound having an NCO content of 5% or more; forming a transparent resin layer mainly composed of polypropylene on this anchor coat layer by extrusion molding; and forming a top coat layer on this transparent resin layer using an aqueous ink mainly composed of a urethane polymer.

17. A method for producing a decorative sheet, comprising the steps of: forming a pattern layer on a polyolefin substrate using an aqueous colored ink; forming an anchor coat layer on this pattern layer to a thickness of 1 μm or more and 3 μm or less using an aqueous ink containing, as resin components, a resin emulsion containing a polyether-based urethane with an acid value of 10 or more and a resin emulsion containing a polycarbonate-based urethane, and, as a curing component, an epoxy compound with an epoxy equivalent of 50 or more; forming a transparent resin layer mainly composed of polypropylene on this anchor coat layer by extrusion molding; and forming a top coat layer on this transparent resin layer using an aqueous ink mainly composed of a urethane polymer.

18. 18. The method for producing a decorative sheet according to claim 16 or 17, 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 dyne or more.

19. 19. The method for producing a decorative sheet according to any one of claims 16 to 18, wherein a peel strength between the anchor coat layer and the transparent resin layer is 15 N / inch or more.

20. 20. The method for producing a decorative sheet according to any one of claims 16 to 19, wherein the peel strength between the anchor coat layer and the transparent resin layer of the decorative sheet after exposure to an environment of 105°C and 100% RH for 24 hours is 5 N / inch or more.

21. The top coat layer contains a silica filler as a gloss adjuster, 21. The method for producing a decorative sheet according to any one of claims 16 to 20, wherein the silica filler has a pore volume of 1 mL / g or more, or an oil absorption amount within the range of 100 mL / 100 g to 200 mL / 100 g.

22. 21. The method for producing a decorative sheet according to any one of claims 16 to 20, characterized in that the top coat layer contains acrylic beads or silicone beads as a gloss adjusting agent.

23. 23. The method for producing a decorative sheet according to any one of claims 16 to 22, characterized in that the top coat layer contains, as weather resistance agents, an ultraviolet absorber having a triazine skeleton and a light stabilizer having a NOR type skeleton.

24. 24. The method for producing a decorative sheet according to any one of claims 16 to 23, characterized in that the top coat layer contains a polyethylene wax as a lubricant.

25. 25. The method for producing a decorative sheet according to any one of claims 16 to 24, wherein a surface of the transparent resin layer facing the top coat layer is surface-treated so that the surface has a wetting index of 60 dynes or more.

26. The method for producing a decorative sheet according to any one of claims 16 to 25, wherein the change in gloss of the top coat layer before and after exposure for 500 hours in an environment of 85°C and 85% RH is within 5%.

27. A method for producing a decorative sheet according to any one of claims 16 to 26, 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.

28. 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 film thickness of the transparent resin layer is in the range of 70 μm or more and 100 μm or less, 28. The method for producing a decorative sheet according to any one of claims 16 to 27, characterized in that the film thickness of the top coat layer is within the range of 3 μm or more and 15 μm or less.

29. A method for producing a decorative sheet as described in claim 16, characterized in that the content of the resin emulsion containing the polyether-based urethane is greater than the content of the resin emulsion containing the polycarbonate-based urethane.

30. A method for producing a decorative sheet as described in claim 16, characterized in that the content of the resin emulsion containing the polyether-based urethane is 70% or more of the total content of the resin emulsion containing the polyether-based urethane and the resin emulsion containing the polycarbonate-based urethane.

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