Decorative sheets and decorative materials

Abstract

We provide decorative sheets that reproduce the texture of real wood and possess high design quality. We also provide high-quality decorative materials that incorporate such decorative sheets. [Solution] A decorative sheet comprising a base layer, a pattern layer provided on the upper side of the base layer, and a surface protection layer provided on the upper side of the pattern layer, wherein the base layer is made of a polyolefin resin, the thickness of the base layer is 10 μm or more and 100 μm or less, the surface protection layer is made of an ionizing radiation curing resin, the surface of the surface protection layer has an uneven structure, the uneven structure of the surface protection layer has a load length ratio Rmr(10%) at a cutting level of 10% of 0.4 or more and 0.7 or less, a root mean square slope Rdq is 0.15 or more and 0.4 or less, and a root mean square height Rq is 2.3 μm or more and 5.6 μm or less.

Description

[Technical Field]

[0001] The present invention relates to decorative sheets and decorative materials. [Background technology]

[0002] Conventionally, decorative sheets have been used for the surface finishing of building materials such as interior materials, joinery, fixtures, furniture, housing equipment, and home appliances in buildings such as houses. Decorative sheets are used, for example, for the surface finishing of interior and exterior materials such as fixtures, furniture, joinery, and flooring, with the purpose of adding aesthetic appeal and durability to these components.

[0003] Design appeal can be enhanced, for example, by creating a wood grain pattern using various printing methods. This allows for a visual reproduction of the appearance of wood material.

[0004] Furthermore, there are decorative sheets in which an uneven surface is formed by embossing, thereby imparting a desired texture and feel to the surface. An example of a decorative sheet with an uneven surface formed by embossing is the decorative sheet described in Patent Document 1. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-108699 [Overview of the project] [Problems that the invention aims to solve]

[0006] The technology described in Patent Document 1, for example, can provide a decorative sheet that has a tactile feel similar to that of real wood, which is created by the unevenness of the vessels and fibers. However, there is a problem in that when you touch the decorative sheet with your hand, it cannot reproduce the cold feeling you get when you touch real wood.

[0007] Based on the above circumstances, the present invention aims to provide a decorative sheet that reproduces the cool feeling one experiences when touching real wood and possesses high design quality. Furthermore, it also aims to provide a high-quality decorative material equipped with such a decorative sheet. [Means for solving the problem]

[0008] To solve the above problems, one aspect of the present invention includes the following:

[0009] [1] A decorative sheet comprising a base layer, a pattern layer provided on the upper side of the base layer, and a surface protection layer provided on the upper side of the pattern layer, wherein the base layer is made of a polyolefin resin, the thickness of the base layer is 10 μm or more and 100 μm or less, the surface protection layer is made of an ionizing radiation curing resin, the surface of the surface protection layer has an uneven structure, the uneven structure of the surface protection layer has a load length ratio Rmr(10%) at a cutting level of 10% of 0.4 or more and 0.7 or less, a root mean square slope Rdq is 0.15 or more and 0.4 or less, and a root mean square height Rq is 2.3 μm or more and 5.6 μm or less.

[0010] [2] The decorative sheet according to [1], comprising an adhesive layer formed on the upper side of the pattern layer and a transparent resin layer formed on the upper side of the adhesive layer and on the lower side of the surface protective layer, wherein the transparent resin layer is made of polyolefin resin and the thickness of the transparent resin layer is 10 μm or more and 100 μm or less.

[0011] [3] The decorative sheet according to either [1] or [2], wherein the precursor of the ionizing radiation-curable resin is acrylate.

[0012] [4] The decorative sheet according to any one of [1] to [3], wherein the precursor of the ionizing radiation-curable resin is a trifunctional acrylate containing a repeating structure, and the number of repetitions of the repeating structure is 3 or more and 15 or less.

[0013] [5] The precursor of the radiation-curable resin is a tetrafunctional acrylate containing a repeating structure, and the number of repetitions of the repeating structure is 35 or less. The decorative sheet according to any one of [1] to [4].

[0014] [6] The surface protection layer contains a cured product of a resin and particles. The decorative sheet according to any one of [1] to [5].

[0015] [7] The particles have an average particle diameter of 3 μm or more and 11 μm or less. The decorative sheet according to [6].

[0016] [8] The particles are contained in the surface protection layer in an amount of 2 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the resin. The decorative sheet according to [6] or [7].

[0017] [9] The pattern layer has a wood grain pattern. The decorative sheet according to any one of [1] to [8].

[0018]

[10] A decorative material comprising the decorative sheet according to any one of [1] to [9], and a base material for a decorative material attached to the lower side of the decorative sheet.

Advantages of the Invention

[0019] According to the present invention, it is possible to provide a decorative sheet that reproduces the cold feeling felt when touching real wood and has high design quality. Further, it is possible to provide a high-quality decorative material provided with such a decorative sheet.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a schematic view of a decorative sheet 1 and a decorative material 100 according to the first embodiment. [Figure 2] FIG. 2 is a micrograph of the surface of the surface protection layer 14. [Figure 3] FIG. 3 is a schematic view showing a decorative sheet 2A according to the second embodiment.

Modes for Carrying Out the Invention

[0021] [First Embodiment] The decorative sheet according to this embodiment will be described below with reference to Figures 1 to 3. Note that in all the following drawings, the dimensions and proportions of each component have been varied as appropriate for clarity. The items described below can be incorporated into each of the above embodiments, either individually or in combination.

[0022] Furthermore, the embodiments shown below illustrate configurations for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited by the material, shape, and structure of the components described below. Various modifications can be made to the technical concept of the present invention within the technical scope defined by the claims described in the claims.

[0023] Figure 1 is a schematic diagram of the decorative sheet 1 and decorative material 100 of the first embodiment. As shown in Figure 1, the decorative sheet 1 has a base layer 12, a pattern layer 13, and a surface protection layer 14. The decorative material 100 has the decorative sheet 1 and a base material 50 for the decorative material.

[0024] The decorative base material 50 is a base material attached to the underside of the decorative sheet 1. The decorative base material 50 is, for example, a board. The board is, for example, a wood-based board, an inorganic board, a metal plate, or a composite board made of multiple materials. The decorative base material 50 may have a shape other than a board. The decorative material 100 having the decorative base material 50 which is a board is a decorative panel. The decorative panel may be flat, bent, or folded.

[0025] The decorative material 100 may also employ a material other than a sheet as the base material 50 for the decorative material. For example, the base material 50 for the decorative material may be a resin molded body.

[0026] 《Anti-Atomic Class》 The base layer 12 is made of a polyolefin resin. Examples of polyolefin resins that can be used include polypropylene and polyethylene. The base layer 12 may be a single layer or a laminate.

[0027] The thickness of the raw material layer 12 is preferably in the range of 10 μm to 100 μm, and more preferably in the range of 50 μm to 100 μm. The effects of making the thickness of the raw material layer 10 μm to 100 μm will be described later.

[0028] The inventors experimentally confirmed that by using a polyolefin resin in the base layer 12, a person touching the decorative sheet will feel the coolness of wood, compared to materials such as polyvinyl chloride.

[0029] 《Picture Layer》 The pattern layer 13 is formed by printing onto the base layer 12 using ink, and is a layer for adding a pattern to the decorative sheet to enhance its aesthetic appeal. The pattern layer 13 is formed, for example, by printing a pattern such as wood grain, stone pattern, or sand pattern. Known printing methods such as gravure printing, offset printing, flexographic printing, screen printing, or inkjet printing can be used as the printing method.

[0030] As the ink binder, for example, nitrated cotton, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl bristyl, polyurethane, acrylic, polyesters, or modified versions thereof can be used individually or in combination. The binder 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. The pattern layer 13 may be formed by curing a layer formed with a curable ink by irradiation with ultraviolet light or electron beams. Among these, the most common method is to use a urethane-based ink and cure it with isocyanate.

[0031] The ink used to form the pattern layer 13 may further contain, in addition to the binder, colorants such as pigments and dyes, extender pigments, solvents, and various additives, which are typically found in inks. Examples of versatile pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolon, cobalt, phthalocyanine, carbon, titanium dioxide, iron oxide, mica, and other pearl pigments.

[0032] 《Surface protective layer》 The surface protection layer 14 is formed on the pattern layer 13. Preferably, the surface protection layer 14 covers the entire upper surface of the pattern layer 13. The surface of the surface protection layer 14 is provided with a ridged, protruding uneven structure (uneven portion 14a).

[0033] Here, in the decorative sheet 1 according to this embodiment, "ridge-like" refers to a convex shape that is linear in plan view. The shape of the uneven portion 14a in plan view may be curved or straight, but it is preferable that it be curved from the viewpoint of fingerprint resistance of the decorative sheet 1. The ridge-like protrusions on the surface of the surface protective layer 14 may or may not be branched in plan view.

[0034] Figure 2 is a micrograph of the surface of the surface protective layer 14. As shown in Figure 2, the ridge-like convex shapes of the uneven portion 14a are each curved, and at least some are adjacent in the width direction. At positions where at least some of the convex shapes are adjacent in the width direction, the cross-section of the surface protective layer 14 parallel to this width direction and the thickness direction of the surface protective layer 14 has a wave shape, such as a sinusoidal shape, in the portion where the uneven structure is provided.

[0035] The uneven structure of the surface protective layer 14 has a load length ratio Rmr(10%) of 0.4 to 0.7 at a cutting level of 10%. Preferably, the load length ratio Rmr(10%) is 0.45 to 0.65, and more preferably 0.5 to 0.6.

[0036] The load length ratio Rmr(10%) is the ratio of the load length of the roughness curve at cutting level 10% to the evaluation length. Cutting level 10% is the level where the distance in the depth direction from the highest point of the roughness curve is 10% of the maximum cross-sectional height Rt. When a user lightly touches a textured surface with their finger, their finger touches the portion from the highest point of the protrusion to approximately 10% of the height of the protrusion. Therefore, the load length ratio Rmr(10%) correlates with the amount of contact between the finger and the protrusion when a user lightly touches the textured surface with their finger. The load length ratio Rmr(10%) and the maximum cross-sectional height Rt are surface texture parameters specified in JIS B0601:2013.

[0037] The load length ratio Rmr(10%) is expressed by the following equation 1.

[0038]

number

[0039] The uneven structure of the surface protective layer 14 has a root mean square slope Rdq of 0.15 or more and 0.4 or less. Preferably, the root mean square slope Rdq is 0.2 or more and 0.35 or less, and more preferably 0.25 or more and 0.3 or less.

[0040] The root mean square slope Rdq is the root mean square of the local slope of the roughness curve at a reference length. The root mean square slope Rdq is a parameter that can be used to evaluate the magnitude of the local slope angle. Specifically, the root mean square slope Rdq quantifies the steepness of the convex or concave parts of a surface texture. The root mean square slope Rdq is a surface texture parameter specified in JIS B0601:2013.

[0041] The root mean square slope Rdq is expressed by the following equation 2.

[0042]

number

[0043] The uneven structure is preferably such that the root mean square height Rq is between 2.3 μm and 5.6 μm. Preferably, the root mean square height Rq is between 3 μm and 5 μm, and more preferably between 3.5 μm and 4.5 μm.

[0044] The root mean square height Rq is the root mean square of the vertical coordinate value Z(x) of the roughness curve at a reference length l. The root mean square height Rq is a parameter that can be used to evaluate the height of the protrusions or depressions contained in a surface texture. The root mean square height Rq is a surface texture parameter specified in JIS B0601:2013.

[0045] The root mean square height Rq is expressed by the following equation 3.

[0046]

number

[0047] The thickness of the surface protective layer 14 is preferably 5 μm to 14 μm. By keeping the thickness of the surface protective layer 14 within the above range, the scratch resistance when used as a building material can be made suitable. Here, the thickness of the surface protective layer 14 is determined by observing the cross-section with a scanning electron microscope and averaging 25 points. Specifically, the thickness of the surface protective layer 14 can be measured by the following method.

[0048] (Thickness of the surface protective layer) The decorative sheet 1 is embedded in a resin such as a cold-curing epoxy resin or a UV-curing resin and allowed to cure completely. Then, the sheet is cut so that the cross-section of the decorative sheet 1 is exposed, and the measurement surface is obtained by mechanical polishing. Subsequently, the thickness of the surface protective layer is measured using a scanning electron microscope (for example, a SIGMA500 scanning electron microscope manufactured by Carl Zeiss Microscopy).

[0049] Length measurements are taken at 25 arbitrary points on the surface protective layer 14, including both the convex and concave parts of the uneven structure. The average length value obtained from these 25 points is defined as the "thickness of the surface protective layer." The measurement conditions are: acceleration voltage of 0.5 keV (low acceleration voltage), SE2 mode for imaging, and 2000x magnification. No sputtering is performed on the measurement sample.

[0050] Furthermore, if the coating liquid for the surface protection layer, described later, does not contain a solvent, the thickness of the coating film made from the coating liquid for the surface protection layer is equal to the thickness of the surface protection layer 14.

[0051] The surface protective layer 14 preferably includes a cured resin and particles. The surface protective layer 14 is an ionizing radiation-curable resin. Here, "ionizing radiation" refers to charged particle beams such as electron beams. Ionizing radiation-curable resins harden when irradiated with ionizing radiation. Ionizing radiation-curable resins can also be hardened by ultraviolet irradiation. The ionizing radiation-curable resin used here hardens when irradiated with light with a wavelength of 200 nm or less, while having a large absorption coefficient for this light.

[0052] The amount of cured ionizing radiation-curable resin in the surface protective layer 14 is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. As the ionizing radiation-curable resin, known materials such as various monomers and commercially available oligomers can be used, for example, (meth)acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins can be used. The ionizing radiation-curable resin may be either an aqueous resin or a non-aqueous (organic solvent) resin.

[0053] The main component of the ionizing radiation-curable resin is preferably acrylate. Here, the main component of the ionizing radiation-curable resin refers to a component that accounts for 60% by mass or more of the ionizing radiation-curable resin. The ionizing radiation-curable resin preferably contains acrylate in an amount of 70 parts by mass or more, and more preferably 80 parts by mass or more. By making acrylate the main component of the ionizing radiation-curable resin, the hardness of the surface protective layer 14 can be made suitable.

[0054] In a preferred embodiment, the acrylate is a trifunctional acrylate containing multiple divalent groups corresponding to the same monomer within the molecule. The "divalent groups corresponding to the same monomer" are hereinafter referred to as "repeating structures." An example of a repeating structure is the -CH2-CH2-O- group (monomer: ethylene oxide (EO)).

[0055] The number of repeating structures within the molecule is preferably between 3 and 15. By using a trifunctional acrylate with a repeating structure of 3 to 15, the molecules in the surface protective layer are of a size that allows for easy movement, making it easier to form an uneven surface that can reproduce the coolness of wood, and also allowing for a suitable hardness of the surface protective layer.

[0056] Examples of trifunctional acrylates with a repeating structure number of 3 to 15 include, for example, trimethylolpropane EO-modified triacrylate (3 moles of EO added; number of repeating structures: 3), trimethylolpropane EO-modified triacrylate (9 moles of EO added; number of repeating structures: 9), trimethylolpropane EO-modified triacrylate (15 moles of EO added; number of repeating structures: 15), and ethoxylated glycerin triacrylate (A-GLY-9E; number of repeating structures: 9).

[0057] In another preferred embodiment, the acrylate is a tetrafunctional acrylate which may contain repeating structures within the molecule. When using a tetrafunctional acrylate, it is preferable to use a mixture of two or more different tetrafunctional acrylates, and the number of repeating structures in this acrylate is preferably 35 or less. Examples of tetrafunctional acrylates include, for example, pentaerythritol tetraacrylate (A-TMMT; number of repeating structures: 0) and ethoxylated pentaerythritol tetraacrylate (ATM-35E; number of repeating structures: 35), and it is particularly preferable to use a mixture of these. By using these mixtures, the distribution of molecular sizes in the surface protective layer becomes suitable for the formation of an uneven structure.

[0058] The above repeating units can be analyzed using MALDI-TOF-MS. Ionizing radiation-curable resins may have a molecular weight distribution. If a molecular weight distribution exists, the number of repeats above should correspond to the molecular weight with the strongest peak in the MALDI-TOF-MS mass spectrum.

[0059] Inorganic particles may be added to the surface protective layer 14 to control the formation of the uneven surface structure. Examples of particles that can be added to the surface protective layer 14 include particles made of organic materials such as polyethylene (PE) wax, polypropylene (PP) wax, and resin beads, or particles made of inorganic materials such as silica, glass, alumina, titania, zirconia, calcium carbonate, and barium sulfate.

[0060] The inorganic particles preferably have an average particle size (D50) of 3 μm or more and 11 μm or less. The average particle size is smaller than the thickness of the surface protective layer 14.

[0061] When the surface protective layer 14 contains particles, wrinkles can be generated more uniformly on the coating surface in the second irradiation step described later. On the other hand, when the surface protective layer 14 contains particles, stain resistance tends to decrease, and it becomes difficult to give a cool, woody feel. By keeping the average particle size (D50) within a desirable range, it is possible to generate wrinkles uniformly without the unevenness of the particles interfering with the "cool, woody feel."

[0062] Here, "average particle size (D50)" refers to the median diameter (D50) measured by a laser diffraction / scattering particle size distribution analyzer. Note that if the coating liquid for the surface protection layer contains particles, the surface protection layer 14 obtained from this coating liquid will also contain particles. The average particle size of the particles contained in the surface protection layer 14 can be determined by observing its cross-section, measuring the particle sizes of multiple particles, and averaging the result. The value obtained in this way is substantially the same as the median diameter (D50) measured by a laser diffraction / scattering particle size distribution analyzer. Therefore, the range of average particle size described above can also be interpreted as the range of average particle size of the particles contained in the surface protection layer 14.

[0063] The amount of particles added is preferably 2 to 5 parts by mass per 100 parts by mass of the resin. Note that "100 parts by mass of resin" refers to the parts by mass of the solid content of the resin.

[0064] When the amount of added particles is within the above range, wrinkles can be generated more uniformly on the surface of the coating in the second irradiation step described later. As a result, the gloss level decreases, and the aesthetic appeal is improved.

[0065] If the amount of added particles is too high, the particles are more likely to fall off the surface protective layer 14, making it difficult to achieve high scratch resistance. Also, if the amount of added particles is too high, it may be difficult to achieve high stain resistance. Furthermore, if the amount of added particles is too low, the effect of creating uniform wrinkles tends to be reduced. Therefore, if the amount of added particles is too low, it may be difficult to achieve a "cold wood texture."

[0066] <Manufacturing method for decorative sheets> The decorative sheet 1, as described with reference to Figure 1, is manufactured, for example, by the following method. Here, for simplification, the base layer 12 and the pattern layer 13 are omitted.

[0067] (Preparation of coating solution for surface protection layer) First, a coating liquid for the surface protective layer is prepared and stirred. The coating liquid for the surface protective layer contains, for example, the resin and particles mentioned above. Here, it is assumed that the main component of the resin precursor is acrylate. With a normal stirring method, the particles may appear to be uniformly mixed at first glance, but due to particle aggregation, etc., the dispersion of particles may become non-uniform in the microscopic region. In this case, wrinkles are less likely to form uniformly on the surface of the surface protective layer 14. In this case, the load length ratio Rmr (10%) of the uneven structure tends to be small. By stirring the coating liquid for the surface protective layer more vigorously or for a longer period compared to a normal stirring method, the above non-uniformity can be eliminated. In this case, the load length ratio Rmr (10%) can be increased.

[0068] In other words, if the load length ratio Rmr(10%) of the resulting uneven structure is smaller than the target value as a result of the manufacturing method for the decorative sheet, the load length ratio Rmr(10%) can be brought closer to the target value by changing the stirring conditions of the coating liquid for the surface protective layer and stirring it more strongly or for a longer period of time.

[0069] The coating solution for the surface protective layer may further contain a solvent and additives for improving the functionality of the final product, such as antimicrobial agents and antifungal agents. The coating solution for the surface protective layer may further contain other additives such as ultraviolet absorbers and light stabilizers. Examples of ultraviolet absorbers that can be used include benzotriazole-based, benzoate-based, benzophenone-based, and triazine-based types. Examples of light stabilizers that can be used include hindered amine-based types. Furthermore, according to the method described herein, a surface protective layer 14 with low gloss can be formed without gloss modifiers (matte additives).

[0070] In the third irradiation step described later, when the entire coating film consisting of the surface protective layer coating liquid is cured by ultraviolet irradiation, it is preferable that the surface protective layer coating liquid further contains a photoinitiator. The photoinitiator is not particularly limited, but examples include benzophenone-based, acetophenone-based, benzoin ether-based, and thioxanthone-based photoinitiators.

[0071] (Formation of coating film) Next, a coating film consisting of a surface protective coating liquid is formed on one side of the pattern layer 13. This coating film can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, and inkjet printing, or by various coating methods such as roll coating, knife coating, microgravure coating, and die coating.

[0072] (1st irradiation step) After forming a coating film consisting of a surface protective coating liquid, a first irradiation step is performed. In the first irradiation step, light with a wavelength of approximately 200 nm to 400 nm (hereinafter referred to as the first radiation) is irradiated onto the coating film. This partially hardens the coating film. By partially hardening the coating film through the first irradiation step, the wrinkled uneven structure (texture) produced by the second irradiation step described later can be uniformly generated. Alternatively, by appropriately setting the irradiation conditions of the first irradiation step, it is possible to adjust the uneven structure, particularly the depth of the uneven structure.

[0073] For the first irradiation step, the light source can be selected from, for example, a high-pressure mercury lamp, a metal halide lamp, and a single-wavelength LED lamp having light with a wavelength of 200 nm to 400 nm.

[0074] The integrated light intensity in the first irradiation process is 2 mJ / cm². 2 More than 100mJ / cm 2 The following is preferable: 10 mJ / cm² 2 More than 80mJ / cm 2 It is more preferable to set it to the following: 20 mJ / cm² 2 More than 60mJ / cm 2The following is even more preferable: If the cumulative light intensity is reduced, the effect of the first irradiation step described above will not be observed. If the cumulative light intensity is increased, the coating film will fully harden, and wrinkles will not be formed in the subsequent second irradiation step.

[0075] (Second irradiation process) Next, the second irradiation process is carried out. In the second irradiation process, light with a wavelength of 200 nm or less (hereinafter referred to as the second radiation) is irradiated onto the coating film. The ionizing radiation-curable resin contained in the surface protective layer coating liquid has a large absorption coefficient for the second irradiation light. Therefore, the second irradiation light incident on the coating film can only reach a distance of several tens to several hundreds of nanometers from its outermost surface. Consequently, in the second irradiation process, the crosslinking reaction proceeds in the surface region of the coating film, forming an extremely thin cured film, while in other regions, the crosslinking reaction does not proceed and the film remains semi-cured.

[0076] The coating film after the second irradiation step has wrinkles on its surface corresponding to the aforementioned uneven portion 14a. The inventors believe the reason why wrinkles form on the coating film surface due to the second irradiation step is as follows.

[0077] As described above, the second radiation can only reach a distance of tens to hundreds of nanometers from the outermost surface of the coating film. In other words, the crosslinking reaction of the ionizing radiation-curable resin due to irradiation with the second radiation occurs only at the surface of the coating film, and in regions further away from the outermost surface than tens to hundreds of nanometers, some areas remain uncured, and highly fluid molecules exist there. These highly fluid molecules swell the cured film, increasing its volume. As a result, it is thought that the cured film buckles in response to the in-plane compressive stress caused by the increase in volume in the in-plane direction, resulting in wrinkles on the surface of the coating film.

[0078] Furthermore, the inventors believe that the reason why a surface protective layer 14 having surface properties characterized by the above-mentioned parameters can be obtained by the above method is as follows.

[0079] As described above, when a coating film made of a surface protective coating liquid is irradiated with a second radiation, a hardened film is formed on its surface, and the hardened film increases in volume in the in-plane direction, causing wrinkles to form on the surface of the coating film. Since the second radiation is usually irradiated from a vertical direction, the increase in volume of the hardened film in the in-plane direction is greater in areas with a nearly horizontal surface compared to areas with an inclined surface. That is, at the tops of convex parts and the bottoms of concave parts, the rate of increase in volume of the hardened film in the in-plane direction is greater than in other parts.

[0080] Furthermore, during the process of creating this wrinkle shape, mass migration occurs within the coating film from areas corresponding to the recesses of the wrinkles to areas corresponding to the protrusions of the wrinkles. As a result, the thickness of the coating film decreases in the recessed areas and increases in the protruding areas. If the coating film is irradiated with the first radiation prior to the second radiation, the mass migration within the coating film due to the in-plane volume increase of the hardened film becomes gentler. In other words, if the coating film is irradiated with the first radiation, deformation of the coating film surface due to irradiation with the second radiation becomes less likely compared to cases where the first radiation irradiation is omitted. However, in areas with greater thickness, deformation is more likely to occur compared to areas with less thickness because there is a larger amount of material that can contribute to deformation.

[0081] Thus, in the convex areas, the rate of increase in the in-plane volume of the hardened film is large, and deformation is more likely to occur. Therefore, if irradiation with the second radiation is continued, the ridge-like convex areas formed on the surface of the coating film expand so that the portion of the cross-section perpendicular to its length that corresponds to the surface of the coating film becomes, for example, a convex curve, and its width also increases.

[0082] As the convex portions expand to have the cross-sectional shape described above, and the distance between the convex portions shortens, the amount of light from the second radiation reaching the concave portions decreases. Therefore, in the concave portions, the rate of increase in the in-plane volume of the hardened film decreases.

[0083] As a result, an uneven structure is formed that has characteristics such as a gentle slope near the top of the protrusions. In other words, it is considered that a surface protective layer 14 having surface properties characterized by the above-mentioned parameters is obtained.

[0084] Furthermore, the uniformity of particle distribution within the coating film affects the uniformity of distribution in convex and concave areas, and therefore affects the surface properties of the surface protective layer 14. Accordingly, the above method eliminates the non-uniformity of particle dispersion by stirring the coating liquid for the surface protective layer more strongly or for a longer period compared to a normal stirring method.

[0085] The second type of radiation can be extracted from excimer VUV (Vacuum Ultra Violet) light. Excimer VUV light can be generated from lamps using noble gases or noble gas halide compounds. When high-energy electrons are supplied from an external source to a lamp containing a noble gas or noble gas halide compound, numerous discharge plasmas (dielectric barrier discharges) are generated. This plasma discharge excites the atoms of the discharge gas (noble gas), causing them to instantaneously enter an excimer state. When returning from this excimer state to the ground state, it emits light in a wavelength range specific to that excimer state.

[0086] The gas used in an excimer lamp can be any conventionally used gas, as long as it emits light of 200 nm or less. As gases, noble gases such as Xe, Ar, and Kr, or mixed gases of noble gases and halogen gases such as ArBr and ArF can be used. The wavelength (center wavelength) of an excimer lamp varies depending on the gas used, and for example, it has wavelengths of approximately 172 nm (Xe), approximately 126 nm (Ar), approximately 146 nm (Kr), approximately 165 nm (ArBr), and approximately 193 nm (ArF).

[0087] Considering the magnitude of the photon energy and the difference between the wavelength and the bonding energy of the organic material, it is preferable to use a xenon lamp that emits excimer light with a central wavelength of 172 nm as the light source. Furthermore, considering the costs of equipment maintenance and material availability, it is also preferable to use a xenon lamp as the light source.

[0088] The second irradiation step is performed in an atmosphere with a low oxygen concentration. Oxygen has a large absorption coefficient for light of 200 nm or less. Therefore, the second irradiation step is preferably performed, for example, in a nitrogen gas atmosphere. The oxygen concentration in the gas phase in the second irradiation step, that is, the residual oxygen concentration in the reaction atmosphere, is preferably 2000 ppm or less, and more preferably 1000 ppm or less.

[0089] In addition, oxygen in the atmosphere inhibits radical polymerization. Therefore, the residual oxygen concentration in the reaction atmosphere affects the formation of wrinkles on the coating film surface. Therefore, when the residual oxygen concentration in the reaction atmosphere is changed, the surface properties of the surface protective layer 14 can also change.

[0090] The integrated light amount of the second radiation is preferably 0.5 mJ / cm 2 or more and 200 mJ / cm 2 or less, more preferably 1 mJ / cm 2 or more and 100 mJ / cm 2 or less, still more preferably 3 mJ / cm 2 or more and 50 mJ / cm 2 or less, even more preferably 5 mJ / cm 2 or more and 30 mJ / cm 2 or less, and most preferably. When the integrated light amount is reduced, the in-plane expansion of the cured film becomes smaller. When the integrated light amount is increased, the surface state of the coating film deteriorates.

[0091] After the second irradiation step is completed, the third irradiation step is performed. In the third irradiation step, the coating film is irradiated with the third radiation to cure the entire coating film. Thereby, the surface protective layer 14 is obtained.

[0092] The third radiation is ionizing radiation such as an electron beam or ultraviolet light having a longer wavelength compared to the first radiation.

[0093] The integrated light amount of the third radiation is preferably 10 mJ / cm 2 or more and 500 mJ / cm 2 or less, more preferably 50 mJ / cm 2 or more and 400 mJ / cm2 It is more preferable to use the following: 100 mJ / cm² 2 More than 300mJ / cm 2 The following is even more preferable.

[0094] The decorative sheet 1 can be manufactured, for example, by the method described above. The decorative sheet 1 may also be manufactured by other methods. For example, a plate may be formed for the surface protective layer 14 using the method described above, and the surface protective layer 14 having an uneven surface structure may be formed by transfer using this plate.

[0095] <Effects> The decorative sheet 1 has a surface protective layer 14 that has the surface properties described above. When the pattern layer 13 of such a decorative sheet 1 has a wood grain pattern, when a user presses the surface of the surface protective layer 14 with their skin and slides their skin across the surface, for example, when a user presses the surface of the surface protective layer 14 with their finger and slides their finger across the surface, the decorative sheet 1 gives the user a "cold woody feel." Such a decorative sheet 1 is not only low-gloss and aesthetically pleasing, but also has excellent tactile properties. The following describes this tactile property.

[0096] In the decorative sheet 1 described above, the load length ratio Rmr (10%) of the uneven structure of the surface protective layer 14 is within the range described above. Therefore, when a user lightly touches the uneven structure with their finger, the contact area between the finger and the protrusions is relatively large. Also, normally, when the decorative sheet 1 is placed at room temperature, the surface temperature of the decorative sheet 1 is lower than the user's body temperature. Therefore, when a user touches the decorative sheet 1 with their finger, the user's heat is easily conducted to the decorative sheet 1, giving the decorative sheet 1 a cool tactile sensation to the user.

[0097] Furthermore, in the decorative sheet 1 described above, by using a polyolefin resin for the base layer, heat from the user is more easily conducted to the decorative sheet 1, making it easier to give the user a cool touch. Also, by setting the thickness of the base layer within the range of 10 μm to 100 μm, the base layer does not retain heat easily, so the cool touch to the user is more likely to last. The synergistic effect of these factors and the uneven structure provided on the surface of the surface protective layer makes it easier to express the "cool wood touch".

[0098] Furthermore, the decorative sheet 1 described above has a root mean square slope Rdq of the uneven structure within the range described above. Also, the decorative sheet 1 described above has a root mean square height Rq of the uneven structure within the range described above. The protrusions forming such an uneven structure are moderately steep and have a moderate size in the height direction. Therefore, when a user slides their finger across the surface of the surface protection layer 14, the decorative sheet 1 stimulates the user's finger, giving the user a tactile sensation of moderate roughness, that is, a tactile sensation similar to that produced by the unevenness of vessels and fibers in actual wood.

[0099] Thus, when the load length ratio Rmr (10%) of the uneven structure is within the range described above, the decorative sheet 1 gives the user a cool touch, and when the root mean square slope Rdq and root mean square height Rq of the uneven structure are within the range described above, the decorative sheet 1 gives the user a wood-like touch. For this reason, the decorative sheet 1 gives the user a tactile sensation that integrates these two sensations, namely, a "cool woody touch."

[0100] Furthermore, when the frequency of irregularities in an uneven structure is similar, an uneven structure with steeply shaped peaks has a smaller load length ratio Rmr(10%) than an uneven structure with gently shaped peaks. In this case, it is possible to distinguish between the two using only the load length ratio Rmr(10%) parameter. On the other hand, an uneven structure with steeply shaped peaks and a high frequency of irregularities may have a similar load length ratio Rmr(10%) to an uneven structure with gently shaped peaks and a low frequency of irregularities. In this case, it is not possible to distinguish between the two using only the load length ratio Rmr(10%) parameter. In other words, the load length ratio Rmr(10%) parameter alone cannot express that the protrusions of an uneven structure are moderately steep and of a moderate size in the height direction (i.e., giving the user a wood-like tactile sensation). Therefore, it is appropriate to use the load length ratio Rmr (10%) in combination with the root mean square slope Rdq as a parameter to express the "cold feel of wood." Furthermore, it is preferable to combine this with the root mean square height Rq as a parameter to express the "cold feel of wood."

[0101] Since the surface protective layer 14 of the decorative sheet 1 has the surface properties described above, it can achieve a low gloss level even without containing a gloss adjuster (matte additive). Because gloss adjusters reduce the oil repellency of the layer formed by the resin material, the surface protective layer 14 containing a gloss adjuster is prone to fingerprints. The surface protective layer 14 without a gloss adjuster does not easily absorb oil, so fingerprints are less likely to adhere to it. In addition, the surface protective layer 14 with excellent oil repellency is less likely to cause oil stains or the adsorption of contaminants. Furthermore, when the surface of the surface protective layer 14 without a gloss adjuster is scratched, the particles of the gloss adjuster do not fall off, and therefore, the decorative sheet 1 containing such a surface protective layer 14 is less likely to experience changes in gloss or scratches.

[0102] Furthermore, as mentioned above, the surface protection layer 14 can achieve a low gloss level. In this case, the reflection of external light onto the surface of the surface protection layer 14 can be reduced. Therefore, for example, if the pattern layer 13 has a wood grain pattern, the wood grain pattern can be clearly seen. In this case, it is particularly easy to give the user the "feel of cool wood." It should be noted that while the above parameters are related to low gloss, other parameters are also involved in achieving low gloss. For this reason, a low-gloss decorative sheet does not necessarily meet the requirements of the above parameters.

[0103] Furthermore, it is believed that the surface protective layer 14 having the above surface properties can be obtained by the method described above for the reasons explained above, as well as for the following reasons.

[0104] In the second irradiation step, oxygen in the gas phase not only absorbs short-wavelength ultraviolet light but also inhibits radical polymerization. The effect of oxygen in the gas phase on radical polymerization is greatest in the portion of the coating film made of ionizing radiation-curable resin adjacent to the gas phase, and decreases as the distance from the coating film surface increases. Therefore, by changing the oxygen concentration in the gas phase in the second irradiation step, the relationship between the distance from the coating film surface and the progress of the crosslinking reaction can be changed.

[0105] When this relationship changes, the thickness of the cured film formed on the surface of the coating by the second irradiation process and the degree of in-plane expansion of the cured film in accordance with the progress of the crosslinking reaction change. The cumulative light intensity in the first and second irradiation processes also affects the thickness of the cured film and the degree of in-plane expansion of the cured film. Furthermore, the thickness of the cured film and the degree of in-plane expansion of the cured film affect the surface properties of the protective layer. In addition, the particle size and amount of particles added in the coating film, as well as the thickness of the coating film, also affect wrinkle formation.

[0106] Therefore, by appropriately setting, for example, the stirring method of the coating liquid for the surface protective layer, the composition of the ionizing radiation-curable resin, the particle size and amount added, the thickness of the coating film, the oxygen concentration in the gas phase during the second irradiation step, and the cumulative light intensity during the first and second irradiation steps, a surface protective layer with desired surface properties can be obtained. This makes it possible to create a decorative sheet that reproduces the texture (gloss, coolness, feel) of the real material while being highly durable.

[0107] [Second Embodiment] Figure 3 is a schematic diagram showing the decorative sheet of the second embodiment, and is a cross-sectional view corresponding to Figure 1. In the following description, components common to the first embodiment are denoted by the same reference numerals, and detailed descriptions are omitted.

[0108] The decorative sheet 2A shown in Figure 3 has a base layer 12, a pattern layer 13, an adhesive layer 25, a transparent resin layer 26, and a surface protection layer 14.

[0109] 《Adhesive layer》 The adhesive layer 25 is formed on the upper side of the pattern layer 13 and covers the surface of the pattern layer 13. The adhesive layer 25 plays the role of bonding the pattern layer 13 and the transparent resin layer 26.

[0110] The material of the adhesive layer 25 is not particularly limited, but can be appropriately selected from resin materials such as acrylic, polyester, polyurethane, and epoxy. The coating method can be appropriately selected depending on the viscosity of the adhesive. Generally, gravure coating is used, and after forming the adhesive layer 25 on the upper surface of the pattern layer 13 with gravure coating, a transparent resin layer 26 is laminated.

[0111] 《Transparent resin layer》 The transparent resin layer 26 is formed on the upper side of the adhesive layer 25 and covers the surface of the adhesive layer 25. By providing the adhesive layer 25, the transparent resin layer 26 can be formed while preventing damage to the pattern layer 13 caused by directly coating the pattern layer 13 with the monomer of the transparent resin layer 26. Similarly, by providing the transparent resin layer 26, the surface protection layer 14 can be formed while preventing damage to the pattern layer 13 caused by directly coating the pattern layer 13 with the monomer of the ionizing radiation-curable resin of the surface protection layer 14. The transparent resin layer 26 is preferably made of a polyolefin resin, and its thickness is preferably 10 micrometers or more and 100 μm or less. By using a polyolefin resin for the transparent resin layer and keeping the thickness within the above range, the thermal conductivity of the decorative sheet can be increased, and the reproduction rate of the "cold wood texture" can be increased regardless of the material to which the decorative sheet is applied. [Examples]

[0112] The present invention will be described in detail with reference to the following examples. The present invention is not limited to the following examples.

[0113] <Example 1> A 50 μm thick resin sheet made of polypropylene was prepared as the base layer 12. A pattern layer was formed on one side of the base layer 12 using oil-based nitrate cotton resin-based gravure printing ink (PCNT (PCRNT) various colors: manufactured by Toyo Ink Co., Ltd.). The pattern of the pattern layer was a wood grain pattern.

[0114] Next, a coating solution for the surface protective layer was prepared. For the surface protective layer, 100 parts by mass of SR9035, a trimethylolpropane EO-modified triacrylate (with 15 moles of EO added) manufactured by Sartomer, was used, along with 2 parts by mass of Silicea 250N silica particles (particle size 5 μm) manufactured by Fuji Silysia Chemical Co., Ltd.

[0115] Next, the coating liquid for the surface protection layer was stirred. The stirring was carried out as follows: First, the coating liquid for the surface protection layer was placed in the stirring container. A ZT-20 (manufactured by Satake Multinics Co., Ltd.) was used as the stirring container. A Satake Multi A mixer AT14-VPR-0.09BI (manufactured by Satake Multinics Co., Ltd.) was used for stirring. The stirring method was central stirring. The power used for stirring the coating liquid for the surface protection layer was 0.75 kW, and the stirring time was 5 minutes.

[0116] Next, a coating liquid for the surface protective layer was applied to the pattern layer 13. The coating film made of the surface protective layer was formed to a thickness of 11.58 μm.

[0117] Subsequently, the first irradiation process was carried out. Specifically, in the atmosphere, a high-pressure mercury lamp emitting ultraviolet light with a main wavelength of 365 nm was used to emit ultraviolet light with an integrated light intensity of 50 mJ / cm² onto the surface of the coating film consisting of a surface protective layer coating liquid. 2 The irradiation was applied in such a manner that the coating film was partially cured.

[0118] Subsequently, a second irradiation process was carried out. Specifically, under atmospheric pressure and in a nitrogen gas atmosphere with an oxygen concentration of 500 ppm, a Xe excimer lamp was used to emit ultraviolet light with a wavelength of 172 nm, accumulating to a total light intensity of 50 mJ / cm². 2 The irradiation was applied in such a manner that wrinkles were created on the surface of the coating.

[0119] Next, the third irradiation step was performed. Specifically, the entire surface of the coating film, which consists of a coating liquid for the surface protective layer, was irradiated with ionizing radiation at a dose of 20 kGy to cure the entire surface, thereby forming the surface protective layer 14. In this way, the decorative sheet of Example 1 was obtained.

[0120] <Example 2> The decorative sheet of Example 2 was obtained by the same method as in Example 1, except that a 10 μm thick resin sheet made of polypropylene was used as the base layer 12.

[0121] <Example 3> The decorative sheet of Example 3 was obtained by the same method as in Example 1, except that a 100 μm thick resin sheet made of polypropylene was used as the raw material layer 12.

[0122] <Example 4> The decorative sheet of Example 4 was obtained by the same method as in Example 1, except that a resin sheet with a thickness of 50 μm made of low-density polyethylene (LDPE) was used as the base layer 12.

[0123] <Example 5> The decorative sheet of Example 5 was obtained by the same method as in Example 1, except that a resin sheet with a thickness of 50 μm made of high-density polyethylene (HDPE) was used as the raw material layer 12.

[0124] <Example 6> Apply a dry laminating adhesive (Mitsui Chemicals Takelac A540: application rate 2g / m²) to the pattern layer. 2 The decorative sheet of Example 6 was obtained by the same method as in Example 1, except that a coating was applied to form an adhesive layer, and then it was bonded to a 5 μm thick transparent resin layer made of polypropylene (PP) by an extrusion lamination method.

[0125] <Example 7> The decorative sheet of Example 7 was obtained in the same manner as in Example 6, except that a transparent resin layer (10 μm thick) made of PP was used.

[0126] <Example 8> The decorative sheet of Example 8 was obtained in the same manner as in Example 6, except that a transparent resin layer (50 μm thick) made of PP was used.

[0127] <Example 9> The decorative sheet of Example 9 was obtained in the same manner as in Example 6, except that a transparent resin layer (100 μm thick) made of PP was used.

[0128] <Example 10> The decorative sheet of Example 10 was obtained in the same manner as in Example 6, except that a transparent resin layer (150 μm thick) made of PP was used.

[0129] <Example 11> A decorative sheet of Example 11 was obtained in the same manner as in Example 1, except that the particle size of the particles added to the surface protective layer 14 was as follows, and the thickness of the surface protective layer 14 was set to 10.76 μm. ·particle Product Name: Silicia 250N (Manufactured by Fuji Silicia Chemical Co., Ltd.) Particle size: 3μm Formula: 5 parts by mass

[0130] <Example 12> A decorative sheet of Example 12 was obtained in the same manner as in Example 1, except that the particle size of the particles added to the surface protective layer 14 was as follows, and the thickness of the surface protective layer 14 was set to 10.00 μm. ·particle Product Name: Silicia 250N (Manufactured by Fuji Silicia Chemical Co., Ltd.) Particle size: 11μm Formula: 5 parts by mass

[0131] <Example 13> Except for setting the particle size of the particles added to the surface protective layer 14 as follows and setting the thickness of the surface protective layer 14 to 12.80 μm, the decorative sheet of Example 13 was obtained in the same manner as in Example 1. ·particle Product Name: Silicia 250N (Manufactured by Fuji Silicia Chemical Co., Ltd.) Particle size: 14μm Formula: 5 parts by mass

[0132] <Example 14> The ionizing radiation-curable resin used for the surface protective layer 14 was as follows, with a particle content of 5 parts by mass. A coating film made of the coating liquid for the surface protective layer was formed to a thickness of 12.07 μm. The decorative sheet of Example 14 was obtained in the same manner as in Example 1. ·Ionizing radiation curable resin Type: Trimethylolpropane EO-modified triacrylate (EO 9 molar addition) Product Name: SR502 (manufactured by Sartomer)

[0133] <Example 15> The ionizing radiation-curable resin used for the surface protective layer 14 was prepared as follows, with a particle composition of 5 parts by mass. A coating film made of the coating liquid for the surface protective layer was formed to a thickness of 13.11 μm. The decorative sheet of Example 15 was obtained in the same manner as in Example 1.

[0134] <Example 16> The ionizing radiation-curable resin used for the surface protective layer 14 was as follows, and no particles were added. Furthermore, a coating film consisting of the surface protective layer coating liquid was formed to a thickness of 6.69 μm. Otherwise, the decorative sheet of Example 16 was obtained in the same manner as in Example 1. ·Ionizing radiation curable resin Type: Trimethylolpropane EO-modified triacrylate (EO 3 molar addition) Product Name: Miramer M3130 (manufactured by Miwon) Composition: 100 parts by mass

[0135] <Example 17> The ionizing radiation-curable resin used for the surface protective layer 14 was as follows, and no particles were added. Furthermore, a coating film consisting of the surface protective layer coating liquid was formed to a thickness of 6.21 μm. Otherwise, the decorative sheet 1 of Example 17 was obtained in the same manner as in Example 1. ·Ionizing radiation curable resin Type: Trimethylolpropane EO-modified triacrylate (EO 9 molar addition) Product Name: SR9035 (manufactured by Sartomer) Amount: 100 parts by mass

[0136] <Example 18> The ionizing radiation-curable resin used for the surface protective layer 14 was as follows, and no particles were added. Furthermore, a coating film consisting of the surface protective layer coating liquid was formed to a thickness of 5.85 μm. Otherwise, the decorative sheet of Example 18 was obtained in the same manner as in Example 1. ·Ionizing radiation curable resin Types: Pentaerythritol tetraacrylate (A-TMMT), Ethoxylated pentaerythritol tetraacrylate (ATM-35E) Product Name: A-TMMT, ATE-35E (Manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) Composition: A-TMMT25 parts by mass: ATE-35E75 parts by mass

[0137] <Comparative Example 1> A decorative sheet for Comparative Example 1 was obtained in the same manner as in Example 3, except that a resin sheet (50 μm thick) made of PVC was used as the base layer.

[0138] <Comparative Example 2> A decorative sheet of Comparative Example 2 was obtained in the same manner as in Example 3, except that a thermoplastic resin layer (5 μm thick) made of PP was provided on the base layer.

[0139] <Comparative Example 3> A decorative sheet of Comparative Example 3 was obtained in the same manner as in Example 3, except that a thermoplastic resin layer (150 μm thick) made of PP was provided on the base layer.

[0140] <Comparative Example 4> A coating film consisting of a surface protective layer coating liquid was formed to a thickness of 11.18 μm. Furthermore, a decorative sheet of Comparative Example 4 was obtained in the same manner as in Example 3, except that no particles were incorporated.

[0141] <Comparative Example 5> A coating film consisting of a surface protective coating liquid was formed to a thickness of 10.88 μm. The amount of particles was 5 parts by mass. Otherwise, the decorative sheet of Comparative Example 5 was obtained in the same manner as in Example 3.

[0142] <Comparative Example 6> A coating film consisting of a surface protective coating liquid was formed to a thickness of 2.94 μm. The amount of particles was 5 parts by mass. Otherwise, the decorative sheet of Comparative Example 6 was obtained in the same manner as in Example 3.

[0143] <Comparative Example 7> The amount of particles added was 5 parts by mass. A coating film consisting of the surface protective coating liquid was formed to a thickness of 16.23 μm. Otherwise, the decorative sheet of Comparative Example 7 was obtained in the same manner as in Example 3. In addition, a coating film consisting of the surface protective coating liquid was formed to a thickness of 11.48 μm.

[0144] <Comparative Example 8> The ionizing radiation-curable resin used for the surface protective layer 14 was as follows, with a particle content of 5 parts by mass. A coating film consisting of the coating liquid for the surface protective layer was formed to a thickness of 11.48 μm. Otherwise, the decorative sheet of Comparative Example 8 was obtained in the same manner as in Example 1. ·Ionizing radiation curable resin Type: Trimethylolpropane EO-modified triacrylate (EO 3 molar addition) Product Name: Miramer M3130 (Manufactured by Miwon)

[0145] <Comparative Example 9> The ionizing radiation-curable resin used for the surface protective layer 14 was as follows, with a particle content of 5 parts by mass. A coating film consisting of the coating liquid for the surface protective layer was formed to a thickness of 10.38 μm. Otherwise, the decorative sheet of Comparative Example 8 was obtained in the same manner as in Example 1. ·Ionizing radiation curable resin Type: Ethylene glycol diacrylate (EO9 molar addition) Product Name: Light Acrylate 9EG-A (Manufactured by Kyoeisha Chemical Co., Ltd.)

[0146] The following evaluations were performed on each of the obtained decorative sheets.

[0147] <Stain Resistance Evaluation> To evaluate stain resistance, a stain test A, as defined by the Japanese Agricultural Standards (JAS), was conducted. Specifically, lines 10 mm wide were drawn on the surface protective layer of each decorative sheet using blue ink, black quick-drying ink, and red crayon, and left for 4 hours. After that, the lines of blue ink, black quick-drying ink, and red crayon were wiped off with a cloth soaked in ethanol. The evaluation criteria were as follows. Decorative sheets that received an A or AA rating were considered acceptable. AA: The lines of each color could be easily wiped away without applying any pressure. A: Although it required some force, I was able to easily wipe away the lines of each color. B: Some of the lines of each color were wiped away, but some stains remained. • C: It was not possible to wipe away the lines of each color.

[0148] <Touch and feel evaluation> Tactile sensation was evaluated using the following method. First, preliminary preparations were made to ensure consistency in evaluation criteria among evaluators regarding surface roughness. Specifically, three standard test specimens with different surface properties were prepared (a specimen with an Rdq of less than 0.15, a specimen with an Rdq between 0.15 and 0.4, and a specimen with an Rdq greater than 0.4). Next, each of the five evaluators, blindfolded, pressed their fingers onto the surface of the standard test specimens and slid their fingers across the surface. After that, they were asked to classify the tactile sensation regarding surface roughness into the following three groups. The above procedure was repeated until the evaluations by each evaluator agreed for three consecutive times or more, and the evaluation results among the evaluators agreed for three consecutive times. • Group 1: Because there was little sense of roughness, it gave a tactile sensation similar to a flat plastic sheet. • Group 2: Because it had a moderate roughness, it provided a tactile sensation similar to that of actual wood, which is caused by the irregularities of the pores and fibers. • Group 3: The roughness was strongly felt, resulting in a sandpaper-like texture.

[0149] <Tactile evaluation of temperature sensation> Next, the tactile sensation related to temperature was evaluated using the following method. First, preliminary preparations were made to ensure consistency in evaluation criteria among evaluators regarding the tactile sensation related to temperature. Specifically, three standard test specimens with different surface properties were prepared (a specimen with Rmr(10%) greater than 0.35 and less than 0.4, a specimen with Rmr(10%) in the range of 0.4 to 0.7, and a specimen with Rmr(10%) greater than 0.7). Next, each of the five evaluators, blindfolded, pressed their fingers against the surface of the standard test specimens and slid their fingers across the surface, and then classified the tactile sensation related to temperature into the following three groups. The above procedure was repeated until the evaluations by each evaluator agreed three or more times in a row, and the evaluation results agreed three times in a row among the evaluators. • Group a: A lukewarm sensation was obtained. • Group b1: A cool tactile sensation similar to that of actual wood was obtained. • Group b2: A slightly cooler tactile sensation was obtained compared to actual wood. • Group c: The texture was too cold.

[0150] <Overall evaluation of tactile sensation> Next, for each of the decorative sheets prepared in the above examples and comparative examples, each of the evaluators was asked to slide their fingers across the surface of the protective layer while pressing down on it, while blindfolded. After that, they were asked to classify the tactile sensations related to surface roughness and temperature into the above groups. This procedure was repeated until the evaluations by each evaluator agreed three or more times in a row, and the evaluation results agreed three times in a row among the evaluators. Based on these results, the tactile sensation was evaluated according to the following criteria. AA (Cold wood texture): This applies when the texture related to surface roughness is classified into group 2, and the texture related to temperature sensation is classified into group b1, and the texture is particularly evaluated as being close to that of actual wood. A1 (Cold woody feel): When the tactile sensation related to surface roughness is classified into group 2, and the tactile sensation related to temperature is classified into group b1. A2 (A cold, woody feel, but not as good as A1): When the tactile sensation related to surface roughness is classified into group 2, and the tactile sensation related to temperature is classified into group b2. D (Tactile sensations other than the cold feel of wood): When the tactile sensation related to surface roughness is classified into a group other than Group 2, or when the tactile sensation related to temperature is classified into Group a or c.

[0151] <Evaluation Results> The results of the stain resistance evaluation and the overall tactile evaluation are shown in Tables 1 to 3.

[0152] [Table 1]

[0153] [Table 2]

[0154] [Table 3]

[0155] The evaluation results confirmed that Examples 1-12 and 14-18 were of high quality in terms of texture and stain resistance.

[0156] Based on the above, it has been confirmed that the present invention is useful. [Explanation of Symbols]

[0157] 1,2A…Decorative sheet, 12…Base layer, 13…Pattern layer, 14…Surface protection layer, 14a…Rimmed area, 25…Adhesive layer, 26…Transparent resin layer, 50…Base material for decorative material, 100…Decorative material, Rdq…Root mean square slope, Rmr…Load length ratio, Rq…Root mean square height

Claims

1. The nuclear franc and, A pattern layer provided on the upper side of the aforementioned raw material layer, The system comprises a surface protective layer provided on the upper side of the pattern layer, The aforementioned raw material layer is made of a polyolefin resin, The thickness of the aforementioned raw material layer is 10 μm or more and 100 μm or less. The aforementioned surface protective layer is formed of an ionizing radiation-curable resin. The surface of the aforementioned surface protective layer is provided with an uneven structure. The aforementioned uneven structure is a decorative sheet in which the load length ratio Rmr(10%) at a cutting level of 10% is 0.4 or more and 0.7 or less, the root mean square slope Rdq is 0.15 or more and 0.4 or less, and the root mean square height Rq is 2.3 μm or more and 5.6 μm or less.

2. An adhesive layer formed on the upper side of the pattern layer, It comprises a transparent resin layer formed above the adhesive layer and below the surface protective layer, The transparent resin layer is made of polyolefin resin. The decorative sheet according to claim 1, characterized in that the thickness of the transparent resin layer is 10 μm or more and 100 μm or less.

3. The decorative sheet according to claim 1 or 2, wherein the precursor of the ionizing radiation-curable resin is acrylate.

4. The acrylate is a trifunctional acrylate containing a repeating structure, The decorative sheet according to claim 3, wherein the number of repeating structures is 3 or more and 15 or less.

5. The acrylate is a tetrafunctional acrylate which may contain a repeating structure. The decorative sheet according to claim 3, wherein the number of repeating structures is 35 or less.

6. The decorative sheet according to claim 3, wherein the surface protective layer comprises a cured resin and particles.

7. The decorative sheet according to claim 6, wherein the particles have an average particle size of 3 μm or more and 11 μm or less.

8. The decorative sheet according to claim 6, wherein the particles are included in the surface protective layer in an amount of 2 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the resin.

9. The decorative sheet according to claim 1, wherein the patterned layer has a wood grain pattern.

10. The decorative sheet according to claim 9, A decorative material comprising a base material for decorative material attached to the lower side of the decorative sheet.

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