Decorative sheet, decorative material and material selection method of decorative sheet

Abstract

To provide a decorative sheet which improves a plurality of physical properties (scratch resistance and contamination resistance), and can efficiently evaluate the plurality of physical properties, a decorative material and a material selection method of a decorative sheet.SOLUTION: A decorative sheet 10 includes a base material layer 1 formed using a polyolefin or polyester resin, a pattern layer 2 formed on the base material layer 1, an adhesive layer 3 formed on the pattern layer 2, a transparent resin layer 4 formed on the adhesive layer 3, and a surface protective layer 5 formed on the transparent resin layer 4, wherein the transparent resin layer 4 contains polyolefin as a main component and a nucleating agent, and has a nanoindentation hardness of 60 MPa or more, a composite elastic modulus of 1.5 GPa or more and a stress relaxation degree of 0.2 or less, and the surface protective layer 5 has a nanoindentation hardness of 220 MPa or more, a composite elastic modulus of 4.0 GPa or more and a stress relaxation degree of 0.15 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a decorative sheet, a decorative material, and a method for selecting materials for a decorative sheet. [Background technology]

[0002]

[0003] In recent years, the demand for high functionality in decorative sheets used on the interior and exterior surfaces of buildings, fittings, furniture, etc. has been increasing due to the diversification of usage environments. In terms of physical properties, various innovations have been implemented to achieve a balance between physical properties that are sometimes traded off, such as scratch resistance, stain resistance, and weather resistance, and decorative sheets with excellent performance have been developed. For example, Patent Document 1 discloses the addition of a matting agent with a specific particle size to a surface protective layer in order to impart scratch resistance and stain resistance to a decorative sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-187378 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, decorative sheets have been used in a wide variety of applications. For example, when used as flooring materials, improvements in multiple physical properties such as scratch resistance and stain resistance, and their stability, are becoming important issues. However, in order to evaluate the above-mentioned multiple physical properties of decorative sheets, it is necessary to carry out a wide variety of measurements, which makes the work complicated. Furthermore, when selecting the material formulation and layer structure during the production of decorative sheets, it is necessary to evaluate the physical properties of a considerable number of samples, which takes a lot of time.

[0005] The present disclosure has been made with a focus on the above-mentioned problems, and aims to provide a decorative sheet, a decorative material, and a method for selecting materials for a decorative sheet that can improve multiple physical properties (scratch resistance and stain resistance) and efficiently evaluate the multiple physical properties. [Means for solving the problem]

[0006] In order to solve the above problems, a decorative sheet according to one embodiment of the present disclosure is a decorative sheet comprising a base layer formed using a polyolefin or polyester resin, a pattern layer formed on the base layer, an adhesive layer formed on the pattern layer, a transparent resin layer formed on the adhesive layer, and a surface protective layer formed on the transparent resin layer, wherein the transparent resin layer is primarily composed of polyolefin and contains a nucleating agent, and has a nanoindentation hardness of 60 MPa or more, a composite modulus of elasticity of 1.5 GPa or more, and a stress relaxation rate of 0.2 or less, and the surface protective layer has a nanoindentation hardness of 220 MPa or more, a composite modulus of elasticity of 4.0 GPa or more, and a stress relaxation rate of 0.15 or less.

[0007] Furthermore, a decorative material according to one aspect of the present disclosure is characterized by comprising a substrate and the decorative sheet according to any one of claims 1 to 4 attached to at least one surface of the substrate. In addition, in order to solve the above-mentioned problems, a material selection method for a decorative sheet according to one embodiment of the present disclosure is a material selection method for a decorative sheet comprising a base layer formed using a polyolefin or polyester resin, a pattern layer formed on the base layer, an adhesive layer formed on the pattern layer, a transparent resin layer formed on the adhesive layer, and a surface protective layer formed on the transparent resin layer, wherein the transparent resin layer is formed from a polyolefin as its main component with the addition of a nucleating agent, and has a nanoindentation hardness of 60 MPa or more, a composite modulus of elasticity of 1.5 GPa or more, and a stress relaxation rate of 0.2 or less, and the surface protective layer has a nanoindentation hardness of 220 MPa or more, a composite modulus of elasticity of 4.0 GPa or more, and a stress relaxation rate of 0.15 or less. [Effects of the Invention]

[0008] According to one aspect of the present disclosure, it is possible to provide a decorative sheet, a decorative material, and a method for selecting materials for a decorative sheet that can improve multiple physical properties (scratch resistance and stain resistance) and efficiently evaluate the multiple physical properties. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of a decorative sheet according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a cross-sectional view schematically illustrating an example of a decorative material according to a modified example of an embodiment of the present disclosure. [Figure 3] 1 is a graph showing a measurement curve obtained by a nanoindentation method. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present disclosure will be described in detail below. Note that FIG. 1 is a schematic diagram, and the size and shape of each part are appropriately exaggerated for ease of understanding. For example, the relationship between the thickness of each layer and the planar dimensions, the thickness ratio of each layer, etc., differ from the actual ones. Furthermore, the embodiments shown below are merely 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.

[0011] Furthermore, the directions of "left and right" and "up and down" in the following explanation are merely definitions for the convenience of explanation and do not limit the technical idea of ​​the present disclosure. Therefore, for example, if the page is rotated 90 degrees, "left and right" and "up and down" are read interchangeably, and if the page is rotated 180 degrees, "left" becomes "right" and "right" becomes "left."

[0012] After extensive research, the present inventors have found that evaluation using values ​​obtained by nanoindentation measurement of the cross section of a decorative sheet (values ​​measured with a nanoindenter) allows for efficient selection of material formulations and layer configurations capable of improving physical properties such as scratch resistance and stain resistance in a decorative sheet. Specifically, they have found that excellent scratch resistance and stain resistance can be easily imparted to a decorative sheet by ensuring that the nanoindentation measurement values, such as the hardness (nanoindentation hardness), composite elastic modulus, and stress relaxation rate obtained by nanoindentation measurement, in the transparent resin layer and surface protective layer satisfy specific conditions (within a certain range). This has led the present inventors to invent a decorative sheet that can achieve both the required scratch resistance and stain resistance, and a decorative material comprising the decorative sheet.

[0013] A decorative sheet 10 according to an embodiment of the present invention will now be described with reference to Fig. 1. Fig. 1 is a cross-sectional view that schematically shows an example of the structure of the decorative sheet 10.

[0014] (Composition of decorative sheet) As shown in Figure 1, decorative sheet 10 comprises a substrate layer (resin substrate) 1, a pattern layer 2 formed on substrate layer 1, an adhesive layer 3 formed on pattern layer 2, a transparent resin layer 4 formed on adhesive layer 3, and a surface protective layer 5 formed on transparent resin layer 4. Decorative sheet 10 may also comprise a primer layer 6 on the surface of substrate layer 1 opposite to the pattern layer 2. Each layer of the decorative sheet 10 will be described below with reference to FIG.

[0015] (Base material layer 1) The substrate layer 1 is made of, for example, a resin substrate. The resin component constituting the substrate layer 1 is preferably polyolefin or polyester. The resin constituting the substrate layer 1 can be arbitrarily selected from existing materials such as polyethylene, polypropylene, polybutylene, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. From the viewpoint of versatility, polyolefin is most preferable as the material for the substrate layer 1. Furthermore, examples of materials other than the above-mentioned 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-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 4-ethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hex ... Examples include materials obtained by homopolymerizing or copolymerizing two or more types of α-olefins (e.g., 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene), 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.

[0016] To improve adhesion between adjacent layers, the front and back surfaces of the base layer 1 may be subjected to surface treatments such as corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet treatment, and dichromate treatment. Furthermore, a primer layer may be provided between the base layer 1 and the pattern layer 2 to ensure adhesion. Furthermore, if the base layer 1 is formed from polyolefin or polyester, adhesion to the pattern layer 2 described below will be ensured, and if the base layer 1 is formed from polyolefin, adhesion to the pattern layer 2 will be even more ensured.

[0017] If it is desired to impart opacity to the decorative sheet 10, a concealing colored sheet may be used as the base layer 1, or a concealing layer (not shown) may be provided above the base layer 1 and below the design layer 2 (between the base layer 1 and the design layer 2). When a colored sheet is used as the base layer 1, the resin material constituting the base layer 1 can be colored by adding a colorant. Examples of colorants that can be used include inorganic pigments (titanium oxide, carbon black, etc.) and organic pigments (phthalocyanine blue, etc.), as well as dyes. The colorant used in this embodiment can be one or more types selected from known or commercially available colorants, and the amount added can be adjusted to achieve the desired opacity and design properties. In addition, various additives such as fillers, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, nucleating agents, ultraviolet absorbers, light stabilizers, heat stabilizers, colorants, and matting agents may be added to the base layer 1 as needed.

[0018] (Picture layer 2) The design layer 2 is, for example, a layer containing a design printed on the base layer 1 using ink. The ink used to form the design layer 2 may contain, for example, a binder resin. The binder resin contained in the ink used to form the design layer 2 may be appropriately selected from, for example, soluble nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, and the like, either alone or modified from these. The ink may be water-based, solvent-based, or emulsion-type, and may be a one-component type or a two-component type using a curing agent. Examples of methods for curing the ink used to form the design layer 2 include methods for 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.

[0019] 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, and light stabilizers that are commonly contained in 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 2 is not particularly limited, and for example, a typical printing method such as gravure printing, offset printing, screen printing, flexographic printing, or inkjet printing can be used.

[0020] (adhesive layer 3) The adhesive layer 3 is a layer provided to bond the pattern layer 2 and the transparent resin layer 4. When the pattern layer 2 is provided only on a portion of the base layer 1, the adhesive layer 3 is provided to bond the base layer 1, the side surfaces of the pattern layer 2, the top surface of the pattern layer 2, and the transparent resin layer 4.

[0021] The material constituting the adhesive layer 3 is not particularly limited, and can be an ink made by appropriately selecting a material that has excellent adhesion to the design layer 2 and the transparent resin layer 4 from, for example, urethane-based, acrylic-based, acrylic silicone-based, fluorine-based, epoxy-based, polyester-based, or other resin materials. The resin component preferably has a reactive group such as a hydroxyl group or a carboxyl group, and is preferably crosslinked with a curing agent having an isocyanate group or a glycidyl group, with crosslinking between a hydroxyl group and an isocyanate group being particularly preferred.

[0022] There is no particular limitation on the method for forming the adhesive layer 3. The adhesive layer 3 can be formed using a common coating method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating.

[0023] When laminating the transparent resin layer 4 onto the base material layer 1 provided with the pattern layer 2, the lamination method is not particularly limited as long as lamination is performed via the adhesive layer 3. For example, various lamination methods such as thermal lamination, extrusion lamination, dry lamination, and sand lamination can be used as the lamination method for the transparent resin layer.

[0024] (Transparent resin layer 4) The transparent resin layer 4 is formed of a transparent resin whose main component is polyolefin. Polyolefins such as polypropylene, polyethylene, polybutene, and various α-olefin copolymers (copolymers of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc.) are used as the material for the transparent resin layer 4. Among these resins, polypropylene is the most preferable material for the transparent resin layer 4. The transparent resin layer 4 of the present embodiment may be a sheet-like layer formed by film formation, or may be a layer formed by laminating already formed sheets. The transparent resin layer 4 may be made of, for example, a highly crystalline polypropylene resin.

[0025] The transparent resin layer 4 preferably contains polyolefin as the main component, accounting for 80% by mass or more, and more preferably 90% by mass or more, of the total mass of the transparent resin layer 4. Note that "a transparent resin layer containing polyolefin as the main component" means that polyolefin accounts for 80% by mass or more of the total mass of the transparent resin layer 4.

[0026] A nucleating agent is added to the transparent resin layer 4 to improve the hardness of the film. In other words, the transparent resin layer 4 is primarily composed of polyolefin and contains a nucleating agent. Here, the nucleating agent is added to promote the formation of crystal nuclei during resin crystallization. There are two types of nucleating agents: melt-type nucleating agents that melt into the base resin and re-precipitate to form crystal nuclei, and non-melt-type nucleating agents that do not melt after being added to the base resin and remain as crystal nuclei with the same particle size. Examples of nucleating agents for polypropylene resin include metal phosphates, metal benzoates, metal pimelates, metal rosin salts, benzylidene sorbitol, chitocridone, cyanine blue, and talc. Addition of a nucleating agent increases the degree of crystallinity during film formation, resulting in improved nanoindentation hardness. The amount (content) of the nucleating agent added to the transparent resin layer 4 is preferably 0.1 mass % or more relative to the total mass of the transparent resin layer 4. If the amount added is less than 0.1 mass %, crystallization does not proceed, and the desired hardness cannot be obtained.

[0027] If necessary, various additives such as ultraviolet absorbers, weather resistance agents such as light stabilizers, heat stabilizers, flame retardants, antiblocking agents, catalyst scavengers, and, within the scope of not impairing the features of this embodiment, colorants, light scattering agents, and gloss adjusters may also be added to the transparent resin layer 4. Examples of heat stabilizers that can be used include phenol-based, sulfur-based, phosphorus-based, and hydrazine-based additives. Examples of flame retardants that can be used include aluminum hydroxide and magnesium hydroxide. Examples of ultraviolet absorbers that can be used include benzotriazole-based, benzoate-based, benzophenone-based, and triazine-based ultraviolet absorbers. Examples of light stabilizers that can be used include hindered amine-based additives. These additives are generally added in any combination.

[0028] The method for producing the transparent resin layer 4 is not particularly limited, and for example, a common method such as calender film formation or extrusion film formation can be used. The transparent resin layer 4 may be provided with surface irregularities, or so-called embossed portions (not shown), to impart design features. Examples of methods for providing the irregularities include a method of subjecting the transparent resin layer 4 to thermal embossing after extrusion molding, or a method of simultaneously embossing the extrusion using a chill roll with irregularities during extrusion molding. More specifically, the irregular pattern (embossed pattern) is directly applied to the transparent resin layer 4, e.g., a highly crystalline polypropylene sheet. Methods include a method of applying an irregular pattern to a polypropylene sheet after film formation using heat and pressure using an embossing plate with an irregular pattern, or a method of simultaneously embossing the polypropylene sheet during film formation using an extruder using a chill roll with an irregular pattern. In this case, colored ink can be embedded in the recesses of the irregular pattern to further enhance the design. The irregular pattern may be provided if necessary, but need not be provided if unnecessary. Furthermore, one or both surfaces of the transparent resin layer 4 may be activated, as necessary, by, for example, corona treatment, plasma treatment, electron beam treatment, ultraviolet treatment, or dichromate treatment.

[0029] In the decorative sheet 10 according to this embodiment, the transparent resin layer 4 satisfies specific conditions for nanoindentation hardness, composite elastic modulus, and stress relaxation, which are nanoindentation measurement values. Specifically, the transparent resin layer 4 satisfies the condition (first condition) that the nanoindentation hardness is 60 MPa or more, the composite elastic modulus is 1.5 GPa or more, and the stress relaxation rate is 0.2 or less for the above three types of nanoindentation measurement values. By satisfying the first condition above, that the transparent resin layer 4 has a nanoindentation hardness of 60 MPa or more, a composite elastic modulus of 1.5 GPa or more, and a stress relaxation rate of 0.2 or less, the interaction with the laminated surface protection layer 5 provides good scratch resistance and contamination resistance suitable for flooring applications. On the other hand, if the nanoindentation hardness of the transparent resin layer 4 is less than 60 MPa, the composite elastic modulus is less than 1.5 GPa, or the stress relaxation rate exceeds 0.2, and the above three types of nanoindentation measurement values ​​do not satisfy the above specific condition (first condition) (are outside the range), the scratch resistance and contamination resistance will be inferior, making it difficult to apply to flooring applications.

[0030] The nanoindentation hardness of the transparent resin layer 4 can be adjusted by improving the crystallinity by adding a nucleating agent, by adjusting the thermal history during film formation, or by adding a soft component resin. Furthermore, by adjusting the nanoindentation hardness as described above, other nanoindentation measurement values ​​(composite elastic modulus and stress relaxation rate) are also adjusted accordingly. The nanoindentation measurement will be described in detail later.

[0031] (Surface protective layer 5) In this embodiment, the surface protective layer 5 is a layer provided to impart functions such as weather resistance, scratch resistance, stain resistance, and designability to the decorative sheet 10. Suitable materials for the surface protective layer 5 include, for example, ionizing radiation curable resins and thermosetting resins. Of these, in order to achieve the hardness required for flooring applications, an ionizing radiation curable resin with a high crosslink density is preferred for the surface protective layer 5. It is particularly preferred to use an ultraviolet (UV) curable resin, as described below.

[0032] The ionizing radiation curable resin may be an electron beam (EB) curable resin or a UV curable resin. For example, known materials such as various monomers and commercially available oligomers may be used. For example, polyfunctional monomers such as urethane acrylate, pentaerythritol triacrylate (PET3A), pentaerythritol tetraacrylate (PET4A), trimethylolpropane triacrylate (TMPTA), and dipentaerythritol hexaacrylate (DPHA), polyfunctional oligomers, or mixtures thereof, are preferably used. An example of a polyfunctional oligomer is Shiko UV-1700B (manufactured by Mitsubishi Chemical Corporation).

[0033] In this embodiment, the surface protection layer 5 preferably contains a UV-curable resin as its main component. The UV-curable resin preferably accounts for 80% by mass or more, and more preferably 90% by mass or more, of the total mass of the surface protective layer 5. More specifically, the UV-curable resin that is the main component of the surface protective layer 5 preferably contains a urethane acrylate having at least four functional groups and dipentaerythritol hexaacrylate. This allows the surface protective layer 5 to have the desired hardness and to suitably control the nanoindentation measurement values. Furthermore, the blending amount of dipentaerythritol hexaacrylate in the entire main component (UV curable resin) of the surface protective layer 5 is preferably 10% by mass or more relative to the mass of the entire UV curable resin, thereby enabling the hardness of the surface protective layer 5 to be more suitably adjusted. By adjusting the number of functional groups in the UV-curable resin (polyfunctional monomer, polyfunctional oligomer) used in the surface protective layer 5 and / or the amount of UV-curable resin, the nanoindentation measurement values ​​of the surface protective layer 5 described below can be suitably controlled, and the decorative sheet 10 can have good physical properties (scratch resistance, contamination resistance) described below.

[0034] A thermosetting resin may also be used for the surface protective layer 5. The thermosetting resin used for the surface protective layer 5 is not particularly limited, and for example, a polymer having a reactive group such as a hydroxyl group or a carboxyl group, such as various acrylic polymers, various polyesters, various polyethers, various polycarbonates, and various polyurethanes, and a curing agent having a difunctional or higher functional isocyanate group, epoxy group, or the like, may be appropriately selected and combined for use.

[0035] Similar to the transparent resin layer 4, the surface protective layer 5 may contain, as needed, various additives such as weathering agents such as ultraviolet absorbers, light stabilizers, and heat stabilizers, flame retardants, antiblocking agents, and catalyst scavengers, as well as colorants, light scattering agents, and gloss adjusters, provided that the features of this embodiment are not impaired. The various additives may be made of the same materials as those used for the transparent resin layer 4.

[0036] In particular, it is preferable to use an ultraviolet absorber having a triazine skeleton or a light stabilizer having a NOR skeleton as a weather resistance agent in the surface protective layer 5. This can improve the weather resistance of the decorative sheet 10. While the various additives mentioned above are generally added in any combination, it is preferable that the surface protective layer 5 contains at least both an ultraviolet absorber having a triazine skeleton and a light stabilizer having a NOR skeleton.

[0037] The method for forming the surface protection layer 5 is not particularly limited, and the surface protection layer 5 may be formed by preparing a coating liquid from the above-mentioned material and applying it by a conventional method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating, and then curing it by a method suitable for the material, such as heat curing or ultraviolet curing. Alternatively, the surface protective layer 5 may be provided after the pattern layer 2 formed on the base layer 1 and the transparent resin layer 4 are bonded together via the adhesive layer 3 .

[0038] In the decorative sheet 10 according to this embodiment, the surface protective layer 5, like the transparent resin layer 4, satisfies specific conditions for three types of nanoindentation measurement values: nanoindentation hardness, composite elastic modulus, and stress relaxation rate. Specifically, the surface protection layer 5 satisfies the condition (second condition) that the nanoindentation hardness is 220 MPa or more, the composite elastic modulus is 4.0 GPa or more, and the stress relaxation rate is 0.15 or less for the above three types of nanoindentation measurement values. By satisfying the second condition above, that is, the surface protective layer 5 has a nanoindentation hardness of 220 MPa or more, a composite elastic modulus of 4.0 GPa or more, and a stress relaxation rate of 0.15 or less, the interaction with the underlying transparent resin layer 4 provides scratch resistance and contamination resistance suitable for flooring applications.

[0039] On the other hand, if the nanoindentation hardness of the surface protective layer 5 is less than 220 MPa, the composite elastic modulus is less than 4.0 GPa, or the stress relaxation rate exceeds 0.15, and the values ​​of the above three types of nanoindentation measurement values ​​do not satisfy the specific condition (the above second condition) of the surface protective layer 5 (outside the above numerical range), the scratch resistance and contamination resistance will be inferior, making it difficult to apply to flooring applications.

[0040] In other words, when the three nanoindentation measurement values ​​of the transparent resin layer 4 satisfy the first condition and the three nanoindentation measurement values ​​of the surface protective layer 5 satisfy the second condition, the multiple physical properties (particularly physical properties suitable for flooring applications) required of the decorative sheet 10 are improved. Therefore, the multiple physical properties can be efficiently evaluated using the nanoindentation measurement values ​​of the transparent resin layer 4 and the surface protective layer 5.

[0041] The nanoindentation hardness of the surface protective layer can be adjusted by changing the crosslink density depending on the number of functional groups in the resin material (oligomer, monomer) used, or by changing the blending amount of the resin material used, as described above. Furthermore, by adjusting the hardness, which is one of the nanoindentation measurement values, as described above, other nanoindentation measurement values ​​(composite elastic modulus, stress relaxation rate) are also adjusted accordingly.

[0042] (Primer layer 6) The decorative sheet 10 according to this embodiment may further comprise a primer layer 6 on the back surface of the base layer 1, which is the surface opposite to the surface on which the design layer 2 is located. The primer layer 6 may be formed from the same component as the binder resin contained in the colored ink for forming the design layer 2.

[0043] The method for forming the primer layer 6 is not particularly limited, and the primer layer 6 may be formed by preparing a coating liquid from the above-mentioned material and applying it by a conventional method such as gravure coating, microgravure coating, comma coating, knife coating, or die coating, and then curing it by a method suitable for the material, such as heat curing or ultraviolet curing. In addition, the primer layer 6 may be provided after forming a laminate having the base layer 1, the pattern layer 2, the adhesive layer 3, the transparent resin layer 4, and the surface protective layer 5 in this order, or the primer layer 6 may be provided in advance on the back surface of the base layer 1, and then a laminate having the base layer 1 with the primer layer 6 provided thereon, the pattern layer 2, the adhesive layer 3, the transparent resin layer 4, and the surface protective layer 5 in this order may be formed.

[0044] Furthermore, since the primer layer 6 is applied to the back surface of the decorative sheet 10, and in consideration of the fact that it will be wound up into a web, inorganic fillers such as silica, alumina, magnesia, titanium oxide, barium sulfate, etc. may be added to the primer layer 6 to avoid blocking and to improve adhesion with the adhesive.

[0045] (Thickness of each layer) The thickness of each layer constituting the decorative sheet 10 of this embodiment will be described below. The thickness of the base layer 1 is preferably in the range of 20 μm to 150 μm, more preferably in the range of 50 μm to 100 μm, taking into consideration printing workability and cost. The 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, taking into consideration printing workability and cost. The thickness of the adhesive layer 3 is preferably in the range of 0.5 μm to 3 μm, more preferably in the range of 1 μm to 2.5 μm, and even more preferably in the range of 1.5 μm to 2 μm, taking into consideration hydrolysis resistance, printing workability, cost, etc. The thickness of the transparent resin layer 4 is preferably in the range of 20 μm to 200 μm, more preferably in the range of 70 μm to 100 μm, taking into consideration printing workability and cost, etc. Considering printing workability, costs, and the like, the thickness of the surface protection layer 5 is preferably in the range of 13 μm to 20 μm, and more preferably in the range of 3 μm to 15 μm.

[0046] If the thickness of each layer is less than the respective lower limit values ​​described above, the function (performance) of each layer may not be sufficiently obtained. Also, even if the thickness of each layer exceeds the respective upper limit values ​​described above, the function (performance) of each layer does not improve significantly, so it is preferable from the viewpoint of manufacturing costs to set the thickness of each layer to be equal to or less than the respective upper limit values. If both the transparent resin layer and the surface protective layer are thin, scratch resistance tends to be poor, and if they are thick, processability tends to be poor.

[0047] Furthermore, in consideration of printing workability, cost, etc., the thickness of the primer layer 6 is preferably in the range of 0.5 μm to 10 μm, and more preferably in the range of 1 μm to 5 μm. If the thickness of the primer layer 6 is in the range of 1 μm to 5 μm, the function (performance) of the primer layer 6 can be reliably exhibited. Additionally, it is preferable that the total thickness of the decorative sheet 10 be within the range of 45 μm or more and 250 μm or less. If the total thickness of the decorative sheet 10 is less than 45 μm, the strength of the entire decorative sheet 10 will be insufficient, and if the decorative sheet 10 is manufactured in-line, for example, there is a risk that the decorative sheet 10 will be damaged during manufacturing. If the total thickness of the decorative sheet 10 exceeds 250 μm, the flexibility of the entire decorative sheet 10 will decrease, and there is a risk that cracks or deformation will occur in the decorative sheet 10. If the total thickness of the decorative sheet 10 is within the range of 45 μm or more and 250 μm or less, printing workability can be easily improved and manufacturing costs can be reduced.

[0048] (Variation) A decorative material according to a modified example of this embodiment of the present disclosure will be described with reference to Fig. 2. The decorative sheet 10 according to this embodiment can be suitably used to prepare a decorative material (for example, a decorative material for floors) by laminating it with a substrate for the decorative material (for example, a wood substrate). Fig. 2 is a cross-sectional view illustrating one structural example of a decorative material 100 according to a modified example of this embodiment of the present disclosure.

[0049] 2, the decorative material 100 according to this modification is obtained by laminating the decorative sheet 10 according to this embodiment onto a substrate 12 so that the surface protective layer 5 of the decorative sheet 10 is the outermost layer. That is, the decorative material 100 differs from the decorative sheet 10 in that it includes an adhesive 11 and a substrate 12.

[0050] (decorative materials) 2, decorative material 100 has a design layer 2, adhesive layer 3, transparent resin layer 4, and surface protection layer 5 laminated in this order on one side of base layer 1 of decorative sheet 10, and a primer layer 6, adhesive 11, and base material 12 provided on the other side of base material layer 1. In other words, decorative material 100 comprises base material 12 and decorative sheet 10, which is a laminate bonded to base material 12. This makes it possible for the decorative material 100 to provide a decorative material with excellent scratch resistance and stain resistance.

[0051] (wood base material) The substrate 12 may be a wood substrate. A wood board is used as the substrate 12, which is a wood substrate. More specifically, examples of wood boards include chipboards and wood fiberboards (MDF, HDF, etc.). Furthermore, a combination of these chipboards or wood fiberboards with wood veneers or wood plywood may also be used as the wood substrate (substrate 12).

[0052] For example, in the decorative material 100, among these wood substrate materials, when chipboard (ten-point average roughness Rzjis: approximately 80 to 250 μm) or a composite substrate having such chipboard on the surface is used, it is possible to suppress the remaining of air bubbles between the decorative sheet 10 and the substrate 12 (wood substrate) using such chipboard. Furthermore, the decorative material 100 using such chipboard as the substrate 12 can exhibit good impact resistance, abrasion resistance, and walking feel. The ten-point average roughness Rzjis is a value measured using a measurement method in accordance with JIS B0601-2001.

[0053] The shape of the base material 12, which is a wood base material, may be a flat plate, taking into consideration that the decorative material 100 is usually installed as a flooring material (flooring). An adhesive 11 can be used to bond the decorative sheet 10 to the base material 12, which is a wood base material. Examples of adhesives that can be used for the adhesive 11 include known adhesives whose active ingredients include polyvinyl acetate, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ionomer, butadiene-acrylonitrile rubber, neoprene rubber, natural rubber, and urethane-based reactive hot melt adhesive (PUR). When bonding the base material 12 (wood base material) and the decorative sheet 10, bonding devices such as a cold press, hot press, roll press, laminator, wrapping machine, edge banding machine, and vacuum press can be used.

[0054] (Effects of this embodiment) The decorative sheet and decorative material according to this embodiment have the following effects. (1) The decorative sheet 10 of this embodiment is a decorative sheet comprising a base layer 1 formed using polyolefin or polyester resin, a pattern layer 2 formed on the base layer 1, an adhesive layer 3 formed on the pattern layer 2, a transparent resin layer 4 formed on the adhesive layer 3, and a surface protective layer 5 formed on the transparent resin layer 4, wherein the transparent resin layer 4 is primarily composed of polyolefin and contains a nucleating agent, has a nanoindentation hardness of 60 MPa or more, a composite modulus of elasticity of 1.5 GPa or more, and a stress relaxation rate of 0.2 or less, and the surface protective layer 5 has a nanoindentation hardness of 220 MPa or more, a composite modulus of elasticity of 4.0 GPa or more, and a stress relaxation rate of 0.15 or less. According to this configuration, it is possible to provide a decorative sheet that improves multiple physical properties, namely scratch resistance and stain resistance, and that allows for efficient evaluation of these multiple physical properties. (2) The surface protective layer 5 of the decorative sheet 10 may contain an ultraviolet curable resin as its main component. According to this configuration, the three nanoindentation measurement values ​​of the surface protective layer 5, namely, the nanoindentation hardness, the composite elastic modulus, and the stress relaxation rate, can be suitably controlled, and multiple physical properties, such as scratch resistance and contamination resistance, can be reliably improved. (3) The ultraviolet curable resin that is the main component of the surface protective layer 5 in the decorative sheet 10 may contain urethane acrylate having at least four functional groups and dipentaerythritol hexaacrylate. According to this configuration, the above three nanoindentation measurement values ​​of the surface protective layer 5 can be more suitably controlled, and multiple physical properties, namely scratch resistance and contamination resistance, can be reliably improved. (4) The content of the nucleating agent in the transparent resin layer 4 of the decorative sheet 10 may be 0.1% by mass or more relative to the total mass of the transparent resin layer 4. According to this configuration, crystallization proceeds favorably and a desired nanoindentation hardness can be obtained, so that the three nanoindentation measurement values ​​of the composite elastic modulus and stress relaxation degree in the transparent resin layer 4 can be more favorably controlled. (5) The decorative material 100 according to this embodiment includes a substrate 12 and a decorative sheet 10 bonded to at least one surface of the substrate 12. According to this configuration, it is possible to provide a decorative material that improves multiple physical properties, namely scratch resistance and stain resistance, and that allows the multiple physical properties to be efficiently evaluated.

[0055] (Decorative sheet manufacturing method) A method for producing the decorative sheet 10 according to this embodiment will now be described. The manufacturing method of the decorative sheet 10 in this embodiment is a manufacturing method of a laminate (decorative sheet) in which a pattern layer 2 is formed on a base layer 1, an adhesive layer 3 is formed on the pattern layer 2, a transparent resin layer 4 is formed on the adhesive layer 3, and a surface protection layer 5 is formed on the transparent resin layer 4. First, a polyolefin-containing substrate layer 1 is formed to a thickness of 20 μm to 150 μm, and a design layer 2 is formed on the substrate layer 1 to a thickness of 0.5 μm to 10 μm. When forming a primer layer 6, it is preferable to form the primer layer 6 simultaneously with the design layer 2 to a thickness of 0.5 μm to 10 μm. Next, an adhesive layer 3 is formed on the design layer 2 to a thickness of 0.5 μm to 3 μm. Next, a transparent resin layer 4 is formed on the adhesive layer 3 by extrusion molding to a thickness of 70 μm to 100 μm. Next, a surface protection layer 5 is formed on the transparent resin layer 4 to a thickness of 3 μm to 15 μm. In this way, the decorative sheet 10 according to this embodiment is manufactured.

[0056] In addition, in the above manufacturing method, the transparent resin layer 4 is formed using polyolefin as the main component with the addition of a nucleating agent, and the transparent resin layer 4 is set to have a nanoindentation hardness of 60 MPa or more, a composite elastic modulus of 1.5 GPa or more, and a stress relaxation rate of 0.2 or less. In addition, in the surface protection layer 5, by adjusting at least one of the crosslink density depending on the number of functional groups in the resin material and the blending amount of the resin material, the nanoindentation hardness is set to 220 MPa or more, the composite elastic modulus is set to 4.0 GPa or more, and the stress relaxation rate is set to 0.15 or less.

[0057] The above-described manufacturing method can produce the decorative sheet 10 according to the present embodiment described above. Therefore, it is possible to obtain a decorative sheet that has improved physical properties, such as scratch resistance and stain resistance, and that can efficiently evaluate these physical properties.

[0058] (How to select materials for decorative sheets) The following describes a method for selecting materials for the decorative sheet 10 of the present embodiment. The method for selecting materials for the decorative sheet 10 of the present embodiment is a method for selecting materials for a laminate (decorative sheet) in which a pattern layer 2 is formed on a base layer 1, an adhesive layer 3 is formed on the pattern layer 2, a transparent resin layer 4 is formed on the adhesive layer 3, and a surface protective layer 5 is formed on the transparent resin layer 4. Specifically, the material selection method involves forming the transparent resin layer 4 with polyolefin as the main component and adding a nucleating agent, and setting the nanoindentation hardness of the transparent resin layer 4 to 60 MPa or more, the composite elastic modulus to 1.5 GPa or more, and the stress relaxation rate to 0.2 or less. In addition, in the surface protection layer 5, by adjusting at least one of the crosslink density depending on the number of functional groups in the resin material and the blending amount of the resin material, the nanoindentation hardness is set to 220 MPa or more, the composite elastic modulus is set to 4.0 GPa or more, and the stress relaxation rate is set to 0.15 or less. The above-described material selection method makes it possible to obtain the decorative sheet 10 according to the present embodiment described above. Therefore, it is possible to obtain a decorative sheet that has improved physical properties, such as scratch resistance and stain resistance, and that can efficiently evaluate these physical properties.

[0059] (nanoindentation measurement value) Next, the nanoindentation measurement values ​​(nanoindentation hardness, composite elastic modulus, and stress relaxation rate) will be explained in detail. In the present disclosure, the nanoindentation measurement values ​​represent three measurements calculated by the nanoindentation method: hardness, composite modulus, and stress relaxation rate. The nanoindentation method is a measurement method in which a quasi-static indentation test is performed on a target object to be measured (in this example, the transparent resin layer 4 and the surface protective layer 5) to obtain the mechanical properties of the sample. The indentation test yields the graph shown in FIG. 3. FIG. 3 is a graph showing a load-displacement curve. The vertical axis of the graph represents the load applied to the layer to be measured, and the horizontal axis represents the indentation depth of the indenter, i.e., the displacement.

[0060] The contact depth hc is calculated by analysis using the Oliver-Pharr method. The contact depth hc can be calculated by the following formula (1).

[0061]

number

[0062] Here, ε is a constant related to the indenter shape in the indentation test. For a Berkovich indenter, this constant is 0.75. The maximum load Pmax and maximum displacement hmax of the unloading curve can be determined based on the graph shown in Figure 3. S is contact stiffness. Contact stiffness S is the slope of the approximate curve immediately after removal when the unloading curve in Figure 3 is fitted with the function of the following equation (2) over the range of 60 to 95% of the maximum load. A, hf, and m in equation (2) represent fitting parameters used in the fitting.

[0063]

number

[0064] Next, the contact projected area Ac, which indicates the cross-sectional area of ​​the indenter, is calculated based on the shape of the indenter and the contact depth hc. The contact projected area Ac can be expressed as a function of the contact depth hc, as shown in the following equation (3). This equation corrects for the influence of the roundness of the indenter tip using correction terms C1 to C5. C1 to C5 were calculated by measuring fused quartz as a test specimen with maximum loads of 20 μN to 10 mN, and the measurement results of the composite elastic modulus under each maximum load condition were consistent with the composite elastic modulus Er of fused quartz, which is 69.6 GPa.

[0065]

number

[0066] Next, the composite elastic modulus Er is calculated based on the contact projected area Ac and the contact stiffness S. The composite elastic modulus Er can be calculated by the following formula (4).

[0067]

number

[0068] The composite elastic modulus Er is determined by measuring the composite elastic modulus at multiple locations, for example, 30 locations, per test piece, and averaging the obtained composite elastic moduli to obtain the composite elastic modulus Er.

[0069] Next, the nanoindentation hardness H is calculated based on the contact projected area Ac and the maximum load Pmax of the unloading curve shown in Fig. 3. The nanoindentation hardness H can be determined by the following formula (5).

[0070]

number

[0071] The degree of stress relaxation is a value (parameter) that indicates the degree to which stress changes with respect to a certain strain. The degree of stress relaxation is calculated based on the maximum load (Fmax) of the load curve and the maximum load (Pmax) of the unload curve in the measurement curve (load-displacement curve) shown in Figure 3 obtained by the nanoindentation method. The degree of stress relaxation can be determined by the following formula (6).

[0072]

number

[0073] A specific method for measuring nanoindentation measurements will be described later.

[0074] (Example) The present invention will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the following examples.

[0075] Example 1 [Preparation of coating material for surface protection layer] UV-curable resin oligomer: urethane acrylate (UA) "EBECRYL (registered trademark) 8301R (hexafunctional, manufactured by Daicel Allnex Corporation)" 80 parts by weight UV curing monomer: dipentaerythritol hexaacrylate (DPHA) (manufactured by Toagosei Co., Ltd.) 20 parts by weight Photopolymerization initiator: Omnirad (registered trademark) 184 (manufactured by IGM Resins BV) 7 parts by weight Filler: Mizukasil (registered trademark) P803 (manufactured by Mizusawa Industrial Chemicals Co., Ltd.), particle size 5 μm... 10 parts by mass UV absorber: Tinuvin® 400 (BASF) 6 parts by weight Light stabilizer: "Tinuvin (registered trademark) 123 (manufactured by BASF)" 3 parts by weight Antibacterial agent: "Apacider (registered trademark) AW (manufactured by Sangi Co., Ltd.)", particle size 2 μm... 0.3 parts by mass The above formulation was used after adjusting the solid content appropriately with ethyl acetate. [Additives for transparent resin layer] UV absorber: benzophenone-based UV absorber: 0.5% by mass Light stabilizer: Hindered amine light stabilizer: 0.5% by mass Nucleating agent: Phosphate ester metal salt nucleating agent: 0.1% by mass

[0076] [Creating decorative sheets] A 55 μm thick polyethylene sheet with opacifying properties was used as the base layer 1, and a 3 μm thick pattern layer 2 was formed on one side of it using a two-component urethane-based pattern ink (V180, manufactured by Toyo Ink Co., Ltd.) by gravure printing.In addition, a primer layer 6 composed of the same resin components as the pattern layer 2 was formed on the other side of the base layer 1. An adhesive layer 3 was formed on the surface of this pattern layer 2 using a gravure printing method with a coating material for the adhesive layer, to a thickness of 2 μm, and then a transparent resin layer 4 of 70 μm in thickness was formed on top of this using a polypropylene resin containing the above-mentioned additives by extrusion lamination. Furthermore, the above-mentioned surface protective layer coating material was used to provide a surface protective layer 5 with a thickness of 6 μm on this transparent resin layer 4 by gravure coating. In this way, the decorative sheet 10 of Example 1 was produced.

[0077] <Example 2> The decorative sheet of Example 2 was produced in the same manner as Example 1, except that the oligomer and monomer compositions of the coating material for the surface protective layer were as follows: Oligomer: Urethane acrylate (UA) "EBECRYL (registered trademark) 4680 (tetrafunctional, manufactured by Daicel Allnex Corporation)" 90 parts by weight Monomer: Dipentaerythritol hexaacrylate (DPHA) manufactured by Toagosei Co., Ltd. 10 parts by weight

[0078] Example 3 The decorative sheet of Example 3 was produced in the same manner as Example 1, except that the amount of nucleating agent added to the transparent resin layer was 0.2%.

[0079] Example 4 The decorative sheet of Example 4 was produced in the same manner as Example 2, except that the amount of nucleating agent added to the transparent resin layer was set to 0.2%.

[0080] <Comparative Example 1> A decorative sheet of Comparative Example 1 was produced in the same manner as in Example 1, except that no nucleating agent was added to the transparent resin layer.

[0081] <Comparative Example 2> The decorative sheet of Comparative Example 2 was produced in the same manner as in Example 1, except that the oligomer and monomer compositions of the coating material for the surface protective layer were as follows: Oligomer: Urethane acrylate (UA) "UN-9200A (bifunctional, manufactured by Negami Chemical Industrial Co., Ltd.)" 80 parts by weight Monomer: Dipentaerythritol hexaacrylate (DPHA) manufactured by Toagosei Co., Ltd. 20 parts by weight

[0082] <Comparative Example 3> The decorative sheet of Comparative Example 3 was produced in the same manner as in Example 1, except that the oligomer and monomer compositions of the coating material for the surface protective layer were as follows: Oligomer: EBECRYL 4680 (tetrafunctional, manufactured by Daicel Allnex Corporation) 100 parts by mass Monomer (DPHA); no additives

[0083] <Comparative Example 4> The decorative sheet of Comparative Example 4 was produced in the same manner as in Example 1, except that the oligomer and monomer compositions of the coating material for the surface protective layer were as follows: Oligomer: UN-9200A (bifunctional, manufactured by Negami Chemical Industrial Co., Ltd.) 100 parts by weight Monomer: No added

[0084] (Measurement of nanoindentation measurements) The nanoindentation measurement values ​​(nanoindentation hardness, composite elastic modulus, and stress relaxation rate) were measured as follows. <Cross-sectional sample creation> The decorative sheets prepared in each Example and Comparative Example were used as samples. First, the front and back surfaces of each decorative sheet were corona-treated, and the film was cut with a razor into 2 x 3 mm strips and embedded in resin. A visible light-curing resin, "Aronix LCR D-800" manufactured by Toa Gosei Co., Ltd., was used as the embedding resin, and after embedding, it was cured by light irradiation. After curing, the embedding resin containing the film pieces was fixed in an insert for an SPM sample holder. Trimming and cross-section cutting of the film were performed with a glass knife at room temperature (25°C). Subsequently, cross-section cutting was performed with a diamond knife at a cutting speed of 3 mm / s and a cutting film thickness of 500 nm until a mirror finish was obtained. A "Leica Microsystems EM UC7 Ultramicrotome" was used as the cross-section cutting device. The cutting direction was horizontal to the layer interface. The cross-sectioned sample (cross-section sample) was fixed in place with an insert for an AFM sample holder and used to measure nanoindentation hardness, composite elastic modulus, and stress relaxation.

[0085] <Measurement> The measurement device used was a Hysitron TI-Premier (product name) manufactured by Bruker Japan Co., Ltd. The indenter used was a Berkovich type diamond indenter manufactured by Bruker Japan Co., Ltd. Nanoindentation measurements were performed by first scanning the surface of the sample in imaging mode with an indenter to obtain height and gradient images, and then positioning the target layers (surface protection layer, transparent resin layer). Then, in displacement control mode, the indenter was indented to a depth of 200 nm at a rate of 100 nm / s, held at the maximum depth for 2 seconds, and then unloaded at a rate of 100 nm / s. Thirty points were designated on the target layer at intervals of 1 μm or more, and an indentation test (indentation and unloading) was performed on each target layer, followed by measurements using the nanoindentation method. To calculate the hardness and composite modulus, we first tested a standard sample of fused quartz and calibrated the relationship between the contact depth and the projected contact area between the indenter and the sample. We then analyzed the unloading curve in the 60-95% range of the maximum load at unloading using the Oliver-Pharr method to calculate the nanoindentation hardness and composite modulus. The stress relaxation was then calculated from the measurement curve (see Figure 3) obtained from the indentation test.

[0086] (evaluation) The decorative sheets of Examples 1 to 4 and Comparative Examples 1 to 4 obtained by the above-mentioned methods were evaluated for scratch resistance and stain resistance as follows. <Scratch resistance evaluation> A pencil hardness test was carried out on the decorative sheets 10 of each example and each comparative example using a "Tester Sangyo HA-301" under a load of 750 g. After the test, the condition of the sample (the occurrence of scratches) was evaluated visually. The evaluation criteria were as follows: <Evaluation criteria> 〇: Scratches occur when the hardness is H or higher ×: Hardness is less than H and scratches occur In this evaluation, "〇" was considered a pass.

[0087] <Evaluation of contamination resistance> A 1% aqueous solution of sodium hydroxide was dropped onto the surface of the decorative sheet 10 described above, and after leaving it for 24 hours, the surface was wiped off and the surface condition was visually evaluated according to the following criteria. <Evaluation criteria> 〇: No trace △: Slight traces ×: Clear traces present In this evaluation, "〇" was considered a pass.

[0088] [Evaluation results] The evaluation results of Examples 1 to 4 and Comparative Examples 1 to 4, along with the decorative sheet compositions and nanoindentation measurement values, are shown in Table 1. In the sheet compositions shown in Table 1, materials that were not added are indicated with "-". Urethane acrylate is abbreviated as "UA" and dipentaerythritol hexaacrylate is abbreviated as "DPHA".

[0089] [Table 1]

[0090] As can be seen from Table 1, all of the decorative sheets of Examples 1 to 4 passed the evaluation for both scratch resistance and stain resistance, demonstrating excellent performance. Specifically, the decorative sheets of Examples 1 to 4 received evaluation results of "Good" (pass) for both scratch resistance and stain resistance, resulting in an overall evaluation of "Good." This confirmed that both scratch resistance and stain resistance could be achieved. This is thought to be because, in the decorative sheets of each Example, all three of the nanoindentation measurement values ​​(hardness, composite modulus, and stress relaxation rate) for the transparent resin layer satisfied the first condition, and further, all three of the nanoindentation measurement values ​​for the surface protective layer 5 satisfied the second condition. On the other hand, in Comparative Examples 1 to 4, the transparent resin layer did not satisfy the first condition or the surface protective layer did not satisfy the second condition, and therefore, scratch resistance and contamination resistance could not be achieved at the same time, resulting in an overall evaluation of "X".

[0091] From the above, it was found that when the nanoindentation measurement values ​​(hardness, composite modulus, and stress relaxation rate) of the transparent resin layer and the surface protective layer satisfy the above-mentioned specific conditions (condition 1 and condition 2), it is possible to improve the multiple physical properties required of the decorative sheet (scratch resistance and stain resistance), that is, the multiple physical properties are all achieved. In other words, it was found that the multiple physical properties (scratch resistance and stain resistance) can be efficiently evaluated by the nanoindentation measurement values ​​of the transparent resin layer and the surface protective layer.

[0092] Furthermore, for example, this embodiment can have the following configuration. (1) A decorative sheet comprising a base layer formed using a polyolefin or polyester resin, a pattern layer formed on the base layer, an adhesive layer formed on the pattern layer, a transparent resin layer formed on the adhesive layer, and a surface protective layer formed on the transparent resin layer, The transparent resin layer is The main component is polyolefin and contains a nucleating agent, The nanoindentation hardness is 60 MPa or more, the composite elastic modulus is 1.5 GPa or more, and the stress relaxation rate is 0.2 or less, The surface protective layer is Nanoindentation hardness is 220 MPa or more, composite elastic modulus is 4.0 GPa or more, and stress relaxation is 0.15 or less. A decorative sheet characterized by: (2) The surface protection layer is mainly composed of an ultraviolet curable resin. The decorative sheet according to (1) above. (3) The ultraviolet curable resin that is the main component of the surface protective layer is Contains a urethane acrylate having a functionality of at least 4 and dipentaerythritol hexaacrylate. The decorative sheet according to (2) above. (4) The content of the nucleating agent in the transparent resin layer is 0.1% by mass or more with respect to the total mass of the transparent resin layer. The decorative sheet according to any one of (1) to (3) above, characterized in that: (5) A substrate; and a decorative sheet according to any one of (1) to (4) above, which is attached to at least one surface of the substrate. A decorative material characterized by: (6) A method for selecting materials for a decorative sheet comprising a base layer formed using a polyolefin or polyester resin, a pattern layer formed on the base layer, an adhesive layer formed on the pattern layer, a transparent resin layer formed on the adhesive layer, and a surface protective layer formed on the transparent resin layer, comprising: the transparent resin layer is formed from a polyolefin as a main component and a nucleating agent added thereto, and is set to have a nanoindentation hardness of 60 MPa or more, a composite elastic modulus of 1.5 GPa or more, and a stress relaxation rate of 0.2 or less; The surface protective layer has a nanoindentation hardness of 220 MPa or more, a composite elastic modulus of 4.0 GPa or more, and a stress relaxation rate of 0.15 or less. A method for selecting materials for decorative sheets. [Industrial Applicability]

[0093] The decorative sheet according to the present disclosure can achieve both scratch resistance and stain resistance, and can therefore be used extremely beneficially in a variety of industries, including the construction industry. [Explanation of symbols]

[0094] 1 Base material layer 2. Picture layer 3 Adhesive layer 4 Transparent resin layer 5 Surface protective layer 6 Primer layer 10 Decorative Sheet 11. Adhesive 12 Base material 100 Cosmetic Materials

Claims

1. A decorative sheet comprising a base layer formed using a polyolefin or polyester resin, a pattern layer formed on the base layer, an adhesive layer formed on the pattern layer, a transparent resin layer formed on the adhesive layer, and a surface protective layer formed on the transparent resin layer, The transparent resin layer is The main component is polyolefin and contains a nucleating agent, The nanoindentation hardness is 60 MPa or more, the composite elastic modulus is 1.5 GPa or more, and the stress relaxation rate is 0.2 or less, The surface protective layer is The nanoindentation hardness is 220 MPa or more, the composite elastic modulus is 4.0 GPa or more, and the stress relaxation rate is 0.15 or less. A decorative sheet characterized by:

2. The surface protection layer is mainly composed of an ultraviolet curable resin.

2. The decorative sheet according to claim 1.

3. The ultraviolet curable resin that is the main component of the surface protective layer is Contains a urethane acrylate having a functionality of at least 4 and dipentaerythritol hexaacrylate.

3. The decorative sheet according to claim 2.

4. The content of the nucleating agent in the transparent resin layer is 0.1 mass% or more with respect to the total mass of the transparent resin layer.

2. The decorative sheet according to claim 1.

5. A substrate; and the decorative sheet according to any one of claims 1 to 4 bonded to at least one surface of the substrate. A decorative material characterized by:

6. A method for selecting materials for a decorative sheet comprising a base layer formed using a polyolefin or polyester resin, a pattern layer formed on the base layer, an adhesive layer formed on the pattern layer, a transparent resin layer formed on the adhesive layer, and a surface protective layer formed on the transparent resin layer, comprising: the transparent resin layer is formed from a polyolefin as a main component and a nucleating agent added thereto, and has a nanoindentation hardness of 60 MPa or more, a composite elastic modulus of 1.5 GPa or more, and a stress relaxation rate of 0.2 or less; The surface protective layer has a nanoindentation hardness of 220 MPa or more, a composite elastic modulus of 4.0 GPa or more, and a stress relaxation rate of 0.15 or less. A method for selecting materials for decorative sheets.

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