Decorative sheet

Abstract

To provide a decorative sheet which has improved wiping property on its surface and has a wrinkle-like uneven surface on the surface.SOLUTION: A decorative sheet has a matte layer 30 having an uneven surface 32, wherein the matte layer contains a resin layer 36 and a plurality of particles 38, the uneven surface has a wrinkle structure, a maximum height Rz specified in JIS B0601:2013 on the uneven surface is 6 μm or less, and an average length RSm specified in JIS B0601:2013 on the uneven surface is 45 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to decorative sheets. [Background technology]

[0002] Decorative sheets have traditionally been used for the interior and exterior decoration of buildings, the surfaces of fixtures, furniture, home appliances, and the interior decoration of vehicles. Decorative sheets can have a design layer. The design layer includes a picture layer corresponding to a predetermined pattern, color, and the like. A matte layer for suppressing gloss may be provided on the surface of the decorative sheet. The matte layer has an uneven surface (a so-called matte surface) on its surface. Light incident on the matte layer is diffusely reflected and diffused by this uneven surface, thereby reducing the gloss on the surface of the matte layer.

[0003] In recent years, a method for producing a textured surface has been proposed in which an excimer light is used to form a wrinkled textured surface on the surface of a resin. One example of such a method for producing a textured surface is disclosed in Patent Document 1. In Patent Document 1, first, an excimer light is irradiated onto the surface of a coating film made of a photocurable resin. Then, ultraviolet light is irradiated onto the coating film to cure the entire coating film. As a result, wrinkles are formed on the surface of the coating film. In Patent Document 1, the wrinkles formed in this manner result in a coating film with low gloss. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-24102 Summary of the Invention [Problem to be solved by the invention]

[0005] With use, decorative sheets may become soiled. When soiling a decorative sheet, it is removed by wiping it off with, for example, a cloth or tissue paper. Therefore, decorative sheets are required to have a surface that is easy to wipe off. That is, it is required that soiling can be easily removed by rubbing the surface of the decorative sheet with a cloth or tissue paper. However, in the past, decorative sheets with a wrinkled, uneven surface on the surface have made it difficult to remove soiling that has adhered to the decorative sheet due to the wrinkled, uneven structure. Therefore, there have been no decorative sheets with a wrinkled, uneven surface on the surface that have achieved good wiping properties.

[0006] An embodiment of the present disclosure aims to improve the wiping properties of a decorative sheet having a wrinkled, uneven surface. [Means for solving the problem]

[0007] A decorative sheet according to one embodiment of the present disclosure comprises: A matte layer having an uneven surface is provided, the matte layer includes a resin layer and a plurality of particles, the uneven surface has a wrinkled structure, The maximum height Rz of the uneven surface as defined in JIS B0601:2013 is 6 μm or less, The mean length RSm of the uneven surface as defined in JIS B0601:2013 is 45 μm or less.

[0008] In a decorative sheet according to one embodiment of the present disclosure, The maximum height Rz is 3 μm or less, The average length RSm may be 40 μm or less.

[0009] In a decorative sheet according to one embodiment of the present disclosure, The plurality of particles may include particles having a maximum dimension equal to or greater than half the thickness of the resin layer.

[0010] In a decorative sheet according to one embodiment of the present disclosure, The plurality of particles may include particles having a maximum dimension equal to or greater than the thickness of the resin layer.

[0011] In a decorative sheet according to one embodiment of the present disclosure, The plurality of particles may have an average particle size of 1 μm or more.

[0012] In a decorative sheet according to one embodiment of the present disclosure, The matte layer may be provided over the entire surface of one side of the decorative sheet.

[0013] In a decorative sheet according to one embodiment of the present disclosure, The 60° specular gloss of the textured surface may be 5 or less as defined in JIS Z8741:1997.

[0014] The decorative material according to one embodiment of the present disclosure comprises: The decorative sheet has an adherend and the decorative sheet described above provided on the adherend. [Effects of the Invention]

[0015] According to one embodiment of the present disclosure, in a decorative sheet having a wrinkled uneven surface on its surface, the wiping properties of the surface are improved. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating an embodiment of the present disclosure, and is a cross-sectional view of an example of a decorative sheet. [Figure 2] FIG. 2 is a photograph of the textured surface of Sample 1. [Figure 3] FIG. 3 is a photograph of the textured surface of Sample 2. [Figure 4] FIG. 4 is a photograph of the textured surface of Sample 3. [Figure 5] FIG. 5 is a photograph of the uneven surface of Sample 4. [Figure 6]FIG. 6 is a photograph of the textured surface of Sample 5. [Figure 7] FIG. 7 is a photograph of the textured surface of Sample 6. [Figure 8] FIG. 8 is a photograph of the uneven surface of Sample 7. [Figure 9] FIG. 9 is a photograph of the textured surface of Sample 8. [Figure 10] FIG. 10 is a photograph of the textured surface of Sample 9. [Figure 11] FIG. 11 is a photograph of the textured surface of Sample 10. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios have been changed and exaggerated from those of the actual objects in order to make the drawings easier to understand. Note that the embodiments shown below are examples of embodiments of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited to these embodiments.

[0018] In this specification, the terms "plate," "sheet," and "film" are not distinguished from one another solely based on differences in name. For example, "sheet" also includes members called "plate" or "film."

[0019] Furthermore, the term "plate surface (sheet surface, film surface)" refers to the surface that coincides with the extension direction of the target plate-shaped (sheet-shaped, film-shaped) member when the target plate-shaped (sheet-shaped, film-shaped) member is viewed overall and in a broad perspective. Furthermore, the normal direction used for a plate-shaped (sheet-shaped, film-shaped) member refers to the direction in which the normal to the plate surface (sheet surface, film surface) of the member extends.

[0020] In this specification, "plan view" refers to the state of a target plate-shaped (sheet-shaped, film-shaped) member as viewed from the normal direction of the member. For example, when a certain plate-shaped member "has a rectangular shape in a plan view," this means that the member has a rectangular shape when viewed from the normal direction to the plate surface.

[0021] Terms used in this specification that specify shapes, geometric conditions, physical characteristics, and their degrees, such as "parallel," "orthogonal," and "identical," as well as ranges of lengths, angles, and values ​​of physical characteristics, are not strictly limited to those ranges but include ranges within which similar functions can be expected, unless otherwise specified to be strictly interpreted.

[0022] The decorative sheet 10 of the embodiment of the present disclosure is used, for example, as a component constituting the outermost layer of the interior and exterior of buildings, the surfaces of fixtures, furniture, and home appliances, and the interior of vehicles. More specifically, the decorative sheet 10 may be used, for example, as interior components for buildings such as walls, ceilings, and floors; exterior components such as exterior walls, eaves ceilings, roofs, fences, and fences; fixtures or fittings such as window frames, doors, door frames, handrails, baseboards, moldings, and other fixtures and fittings; general furniture such as chests of drawers, shelves, and desks; kitchen furniture such as dining tables and sinks; surface decorative panels for cabinets and the like for home appliances and office automation equipment; and interior and exterior components for vehicles. The decorative sheet 10 may also be used for packaging materials, antiglare films for displays, whiteboards or blackboards, various cards such as credit cards, cash cards, telephone cards, and various certificates; various keyboard keys; transparent panels (window glass, etc.) for windows, doors, and partitions; artificial leather, etc.

[0023] The decorative sheet 10 of this embodiment may be laminated on another member (adherend). In this case, the adherend and the decorative sheet 10 provided on this adherend constitute a decorative material. The adherend may be, for example, a member that constitutes the lower layer of the interior and exterior of a building, the surface of fittings, furniture, home appliances, etc., or the interior of a vehicle, etc.

[0024] The decorative sheet 10 of this embodiment includes a matte layer 30. The matte layer 30 has an uneven surface 32 and a back surface 34. The uneven surface 32 and the back surface 34 face each other and face away from each other. The uneven surface 32 constitutes the surface of the matte layer 30. The uneven surface 32 is a so-called matte surface. Light incident on the matte layer 30 is diffused by the uneven surface 32, thereby reducing the gloss on the surface of the matte layer 30. In other words, the matte layer 30 exhibits a matte effect. In this embodiment, the uneven surface 32 has a specific shape. Therefore, dirt can be easily removed by rubbing the dirty areas of the uneven surface 32 with a cloth, tissue paper, or the like. In other words, the wiping ability of dirt from the uneven surface 32 is improved. In particular, in the decorative sheet 10 of this embodiment, the uneven surface 32 has a specific shape, which improves the wiping ability of dirt while still providing a sufficient matte effect. The shape of the uneven surface 32 will be described later.

[0025] An example of a decorative sheet 10 having such a matte layer 30 will be described below with reference to FIG. 1. FIG. 1 shows a cross section of an example of the decorative sheet 10. In the illustrated example, the decorative sheet 10 has a substrate 12, a design layer 20, an adhesive layer 14, a transparent resin layer 16, a primer layer 18, and a matte layer 30, in that order. Note that none of the substrate 12, design layer 20, adhesive layer 14, transparent resin layer 16, and primer layer 18 are essential components of the decorative sheet 10. The decorative sheet 10 may not have one or more of the substrate 12, design layer 20, adhesive layer 14, transparent resin layer 16, and primer layer 18. The decorative sheet 10 may also have other components (layers) intended to perform specific functions.

[0026] The substrate 12 has a function of supporting the matte layer 30. In particular, in this embodiment, the substrate 12 supports the design layer 20, the adhesive layer 14, the transparent resin layer 16, the primer layer 18, and the matte layer 30. The substrate 12 is disposed facing the back surface 34 of the matte layer 30. The substrate 12 may be a film-like member. The thickness of the substrate 12 may be 10 μm or more and 1 mm or less. Preferably, the thickness of the substrate 12 may be 20 μm or more and 300 μm or less.

[0027] The substrate 12 may be made of, for example, a resin material, a metal material, or a fibrous material. The resin material may be, for example, a polyester resin such as polyethylene terephthalate, an olefin resin such as polyethylene or polypropylene, a vinyl chloride resin such as polyvinyl chloride, or an acrylic resin. The metal material may be, for example, aluminum, iron, copper, gold, silver, chromium, nickel, cobalt, tin, titanium, or an alloy thereof. The fibrous material may be, for example, paper, woven fabric, nonwoven fabric, or a resin-impregnated material thereof. The substrate 12 may include only one layer made of these materials. Alternatively, the substrate 12 may include multiple layers made of these materials. When the substrate 12 includes multiple layers, the multiple layers may be made of different materials.

[0028] The design layer 20 has the function of displaying a design that should be visible to an observer observing the decorative sheet 10. This design may be, for example, a picture, photograph, figure, pattern, mark, letter, color, or other pattern. The design layer 20 may also display a monochrome color pattern as a design. The design layer 20 is disposed facing the back surface 34 of the matte layer 30. In this embodiment, the design layer 20 is disposed between the substrate 12 and the matte layer 30. The thickness of the design layer 20 may be 0.5 μm or more and 20 μm or less. Preferably, the thickness of the design layer 20 may be 1 μm or more and 10 μm or less. More preferably, the thickness of the design layer 20 may be 2 μm or more and 5 μm or less.

[0029] The design layer 20 may include a coloring layer 22 and a pattern layer 24. The coloring layer 22 is a layer that imparts a desired color to the entire surface of the substrate 12. The coloring layer 22 may be a so-called solid layer. The coloring layer 22 may have a single color. Alternatively, the coloring layer 22 may have a pattern composed of multiple colors. The pattern layer 24 is a layer that constitutes the design to be displayed by the design layer 20. The coloring layer 22 and the pattern layer 24 may each be formed by coating, printing, or the like using ink. For example, an ink containing a binder resin and a colorant such as a pigment or dye may be used. Note that the design layer 20 may have only either the coloring layer 22 or the pattern layer 24. That is, the design layer 20 may have only the coloring layer 22 or only the pattern layer 24.

[0030] The transparent resin layer 16 functions to protect the design layer 20. The transparent resin layer 16 also functions to increase the strength of the decorative sheet 10. The transparent resin layer 16 is disposed facing the back surface 34 of the matte layer 30. In this embodiment, the transparent resin layer 16 is disposed between the design layer 20 and the matte layer 30. The transparent resin layer 16 is formed of a transparent resin material. Examples of the resin material include polyolefin resin, polyester resin, polycarbonate resin, acrylonitrile-butadiene-styrene resin (ABS resin), acrylic resin, and vinyl chloride resin. The transparent resin layer 16 may contain additives such as weathering agents, ultraviolet absorbers, light stabilizers, and colorants. The thickness of the transparent resin layer 16 may be 20 μm or more and 150 μm or less. Preferably, the thickness of the transparent resin layer 16 may be 40 μm or more and 120 μm or less. More preferably, the thickness of the transparent resin layer 16 may be 60 μm or more and 100 μm or less.

[0031] As used herein, "transparent" means that the visible light transmittance is 50% or more, preferably 80% or more. The visible light transmittance is determined as the average value of the total light transmittance at each wavelength measured in 1-nm increments within the measurement wavelength range of 380 nm to 780 nm using a spectrophotometer (Shimadzu Corporation's "UV-3100PC," compliant with JIS K0115). "Transparent" also includes colorless transparency and colored transparency.

[0032] The adhesive layer 14 functions to bond the design layer 20 and the transparent resin layer 16 together. If the decorative sheet 10 does not have the design layer 20, the adhesive layer 14 may bond the substrate 12 and the transparent resin layer 16 together. The adhesive layer 14 may be made of, for example, a urethane adhesive, an acrylic adhesive, an epoxy adhesive, or a rubber adhesive. The thickness of the adhesive layer 14 may be 0.1 μm or more and 30 μm or less. Preferably, the thickness of the adhesive layer 14 may be 1 μm or more and 15 μm or less. More preferably, the thickness of the adhesive layer 14 may be 2 μm or more and 10 μm or less.

[0033] The primer layer 18 functions to improve adhesion between the transparent resin layer 16 and the matte layer 30. The primer layer 18 is formed, for example, from a resin material. The resin material may be a resin such as a urethane resin, an acrylic polyol resin, an acrylic resin, an ester resin, an amide resin, a butyral resin, a styrene resin, a urethane-acrylic copolymer, a polycarbonate-based urethane-acrylic copolymer, a vinyl chloride-vinyl acetate copolymer resin, a vinyl chloride-vinyl acetate-acrylic copolymer resin, a chlorinated propylene resin, a nitrocellulose resin, or a cellulose acetate resin. The primer layer 18 may contain additives such as an ultraviolet absorber or a light stabilizer, as needed. The thickness of the primer layer 18 may be 0.1 μm or more and 10 μm or less. Preferably, the thickness of the primer layer 18 may be 1 μm or more and 8 μm or less. More preferably, the thickness of the primer layer 18 may be 2 μm or more and 6 μm or less.

[0034] The matte layer 30 is a layer that provides a matte effect on the surface of the decorative sheet 10. The matte layer 30 has an uneven surface 32 provided on its surface. If the decorative sheet 10 has a substrate 12, the uneven surface 32 faces away from the substrate 12. The uneven surface 32 is a so-called matte surface. Light incident on the matte layer 30 is diffused by the uneven surface 32. This reduces the gloss on the surface of the matte layer 30. In other words, the matte effect is provided by the matte layer 30. Such a matte layer 30 may be provided over the entire surface of one side of the decorative sheet 10. Alternatively, the matte layer 30 may be provided on only a portion of one side of the decorative sheet 10. In this embodiment, the matte layer 30 includes a resin layer 36 and a plurality of particles 38. The resin layer 36 constitutes the main body of the matte layer 30. The uneven surface 32 is formed on the surface of the resin layer 36. In other words, the resin layer 36 has the uneven surface 32. The uneven surface 32 has a wrinkled structure. The plurality of particles 38 function as a wrinkle-forming agent for imparting a specific wrinkled structure to the uneven surface 32.

[0035] The wrinkle structure is a structure including a streak-like uneven structure (see FIGS. 2 to 11). In particular, the wrinkle structure of this embodiment includes streak-like protrusions and / or streak-like recesses. The streak-like protrusions and / or streak-like recesses have irregular shapes and are irregularly arranged in a plan view. The wrinkle structure may include a plurality of curved streak-like protrusions and a recess formed by being surrounded by the plurality of protrusions. The wrinkle structure may also include a plurality of curved streak-like recesses and a protrusion formed by being surrounded by the plurality of recesses. "Curved" means that, in a plan view, the direction of extension of one streak-like protrusion or recess has an inverted portion where it is reversed from one side to the other. The wrinkle structure may include meandering streak-like protrusions and a recess formed by being surrounded by the meandering streak-like protrusions. The wrinkle structure may also include meandering streak-like recesses and a protrusion formed by being surrounded by the meandering streak-like recesses. "Meandering" means that, in a planar view, one streak-like convex or concave portion includes two or more inverted portions, and the extension directions of the convex or concave portions are reversed in opposite directions in two adjacent inverted portions of one convex or concave portion.

[0036] The convex portions and concave portions in the wrinkle structure may be distinguished from each other, for example, by utilizing the difference in brightness of the image of the surface of the decorative sheet 10. For example, the darkest portion in the density distribution image of the surface of the decorative sheet 10 is designated as gradation 255, and the lightest portion in the density distribution image is designated as gradation 0, and the density of the density distribution image is divided into gradations 0 to 255. Of these, gradations 0 to 127 may be designated as concave portions, and gradations 128 to 255 may be designated as convex portions by binarization processing. The gradation threshold for distinguishing between concave portions and convex portions can be set arbitrarily.

[0037] The thickness of the matte layer 30 may be 1 μm or more. Preferably, the thickness of the matte layer 30 may be 2 μm or more. More preferably, the thickness of the matte layer 30 may be 3 μm or more. Even more preferably, the thickness of the matte layer 30 may be 4 μm or more. Alternatively, the thickness of the matte layer 30 may be 300 μm or less. Preferably, the thickness of the matte layer 30 may be 200 μm or less. More preferably, the thickness of the matte layer 30 may be 100 μm or less. Even more preferably, the thickness of the matte layer 30 may be 50 μm or less. In this embodiment, the thickness of the matte layer 30 refers to the thickness of the matte layer 30 excluding the particles 38. In other words, the thickness of the matte layer 30 is the thickness of the resin layer 36. The thickness of the resin layer 36 is determined by measuring the thickness at 20 points on an image of a cross section parallel to the normal direction of the resin layer 36 taken using a scanning electron microscope (SEM), and calculating the arithmetic mean of the thickness values ​​at the 20 points. The acceleration voltage of the SEM is set to 3 kV, and the magnification is set according to the thickness. The same applies to the thicknesses of the other layers.

[0038] The textured surface 32 is required to fully exhibit a matte effect on the surface of the decorative sheet 10. At the same time, the surface of the decorative sheet 10 is also required to have good wiping properties. However, in the past, decorative sheets with a wrinkled surface have had difficulty removing dirt adhering to the decorative sheet due to the wrinkled structure. Therefore, no decorative sheets with a wrinkled surface have achieved good wiping properties. The present inventors conducted extensive research into the wiping properties of decorative sheets with a wrinkled surface and found that imparting a specific shape to the surface of the matte layer 30 (the textured surface 32) improves the wiping properties of the surface of the decorative sheet 10. In particular, they found that by setting the maximum height Rz and average length RSm of the textured surface 32, as specified in JIS B0601:2013, within a predetermined range, the matte layer 30 still exhibits a sufficient matte effect while effectively improving the wiping properties of dirt on the surface of the matte layer 30 (the textured surface 32). The shape of the uneven surface 32 in this embodiment will be described below.

[0039] The maximum height Rz of the uneven surface 32, as defined in JIS B0601:2013, is 6 μm or less. The maximum height Rz of the uneven surface 32 is the arithmetic mean of the maximum heights Rz at any 20 locations on the uneven surface 32. The maximum height Rz can be measured using a shape analysis laser microscope (Keyence Corporation, VK-X150 (controller) / VK-X160 (measuring unit)). The maximum height Rz is one of the peak and height parameters of a profile curve, and is the sum of the height of the highest peak and the depth of the deepest valley in the profile curve over a reference length. A larger maximum height Rz indicates the presence of valleys with greater depths as viewed from the peaks of the peaks, and a tendency for such valleys to be abundant. According to the inventors' research, when the wrinkled uneven surface 32 has depressions with greater depths as viewed from the peaks of the peaks, contaminants that have entered these depressions may not be sufficiently removed even by rubbing with a cloth, tissue paper, or the like. That is, the inventors' studies have found that contaminants that have entered the recesses can be more easily removed by reducing the depth of the recesses as seen from the top of the convex portions of the textured surface 32. In particular, it has been found that for the textured surface 32 having a wrinkled structure, contaminants that have entered the recesses of the textured surface 32 can be more easily removed by setting the maximum height Rz to 6 μm or less. It has not been known in the past that adjusting the maximum height Rz of a textured surface having a wrinkled structure can make it easier to remove contaminants that have entered the recesses of the textured surface. Therefore, the technology of this embodiment, which improves the wiping ability of the textured surface 32 by setting the maximum height Rz of the textured surface 32 having a wrinkled structure to 6 μm or less, makes a significant technical contribution to the prior art.

[0040] Preferably, the maximum height Rz may be 3 μm or less. Furthermore, the maximum height Rz of the uneven surface 32 may be 0.5 μm or more. In this case, the maximum height Rz of the uneven surface 32 is ensured. This allows the uneven surface 32 to appropriately exhibit a matte effect. Preferably, the maximum height Rz may be 1 μm or more. Note that the cutoff value for measuring the maximum height Rz in this specification is 0.8 mm.

[0041] The mean length RSm of the uneven surface 32, as defined in JIS B0601:2013, is 45 μm or less. The mean length RSm of the uneven surface 32 is the arithmetic mean of the mean lengths RSm of any 20 locations on the uneven surface 32. The mean length RSm can be measured using a shape analysis laser microscope (Keyence Corporation, VK-150 (controller) / VK-160 (measuring unit)). The mean length (mean length of curved elements) RSm is a horizontal parameter of the profile curve and is the average length of the profile curve elements over a reference length. The smaller the mean length RSm, the narrower the widths of the convex and concave portions, indicating that the surface shape tends to have narrower convex and concave portions. In this embodiment, when the mean length RSm of the uneven surface 32 is 45 μm or less, the uneven surface 32 has a fine wrinkle structure. Therefore, the gloss on the surface of the matte layer 30 is effectively reduced. In other words, the uneven surface 32 fully exhibits a matte effect.

[0042] Preferably, the average length RSm may be 40 μm or less. Furthermore, the average length RSm on the uneven surface 32 may be 5 μm or more. In this case, the matte layer 30 can be produced stably. Preferably, the average length RSm may be 10 μm or more. Note that the cutoff value for measuring the average length RSm in this specification is 0.8 mm.

[0043] The 60° specular gloss of the uneven surface 32 as defined in JIS Z8741:1997 may be 5 or less. The 60° specular gloss can be measured, for example, using a gloss meter (MICRO-TRI-GLOSS, manufactured by BYK Gardner). When the gloss of the uneven surface 32 is 5 or less, the uneven surface 32 can exhibit a sufficient matte effect. The gloss of the uneven surface 32 may be 1 or more.

[0044] The resin layer 36 includes a resin composition. The resin composition used for the resin layer 36 may include an ionizing radiation-curable resin. The ionizing radiation-curable resin is a resin having an ionizing radiation-curable functional group. The ionizing radiation-curable functional group is a group that crosslinks upon irradiation with ionizing radiation. The ionizing radiation-curable functional group may be, for example, a functional group having an ethylenic double bond, such as a (meth)acryloyl group, a vinyl group, or an allyl group. In this specification, a (meth)acryloyl group refers to an acryloyl group or a methcroyl group. In this specification, a (meth)acrylate refers to an acrylate or a methacrylate. In addition, ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing and / or crosslinking molecules. Examples of ionizing radiation include electromagnetic waves such as ultraviolet (UV) rays, electron beams (EB), X-rays, and gamma rays, as well as charged particle beams such as alpha rays and ion beams.

[0045] The ionizing radiation curable resin may be an electron beam curable resin or an ultraviolet ray curable resin. The ionizing radiation curable resin may be appropriately selected from polymerizable monomers and polymerizable oligomers that have been conventionally used as ionizing radiation curable resins.

[0046] The polymerizable monomer is preferably a (meth)acrylate-based monomer having a radically polymerizable unsaturated group in the molecule. In particular, the polymerizable monomer is preferably a polyfunctional (meth)acrylate monomer. The polyfunctional (meth)acrylate monomer may be a (meth)acrylate monomer having two or more ionizing radiation-curable functional groups in the molecule, and having at least a (meth)acryloyl group as the functional group. The number of functional groups in the polyfunctional (meth)acrylate monomer may be 2 or more and 8 or less. Preferably, the number of functional groups in the polyfunctional (meth)acrylate monomer may be 2 or more and 6 or less. These polyfunctional (meth)acrylates may be used alone or in combination of two or more.

[0047] The polymerizable oligomer may be, for example, a (meth)acrylate oligomer having two or more ionizing radiation-curable functional groups in the molecule and having at least a (meth)acryloyl group as the functional group. The polymerizable oligomer may be, for example, a urethane (meth)acrylate oligomer, an epoxy (meth)acrylate oligomer, a polyester (meth)acrylate oligomer, a polyether (meth)acrylate oligomer, a polycarbonate (meth)acrylate oligomer, an acrylic (meth)acrylate oligomer, etc. Furthermore, the polymerizable oligomer may also be a highly hydrophobic polybutadiene (meth)acrylate oligomer having a (meth)acrylate group in the side chain of a polybutadiene oligomer, a silicone (meth)acrylate oligomer having a polysiloxane bond in the main chain, an aminoplast resin (meth)acrylate oligomer obtained by modifying an aminoplast resin having many reactive groups in a small molecule, or an oligomer having a cationically polymerizable functional group in the molecule, such as a novolac epoxy resin, a bisphenol epoxy resin, an aliphatic vinyl ether, or an aromatic vinyl ether.

[0048] These polymerizable oligomers may be used alone or in combination of two or more. The polymerizable oligomer may be a urethane (meth)acrylate oligomer, an epoxy (meth)acrylate oligomer, a polyester (meth)acrylate oligomer, a polyether (meth)acrylate oligomer, a polycarbonate (meth)acrylate oligomer, or an acrylic (meth)acrylate oligomer. Preferably, the polymerizable oligomer may be a urethane (meth)acrylate oligomer or a polycarbonate (meth)acrylate oligomer. More preferably, the polymerizable oligomer may be a urethane (meth)acrylate oligomer.

[0049] The number of functional groups of these polymerizable oligomers may be 2 or more and 8 or less. Preferably, the number of functional groups of the polymerizable oligomers may be 2 or more and 6 or less. The weight average molecular weight of the polymerizable oligomers may be 2500 or more and 7500 or less. Preferably, the weight average molecular weight of the polymerizable oligomers may be 3000 or more and 7000 or less. More preferably, the weight average molecular weight of the polymerizable oligomers may be 3500 or more and 6000 or less. Here, the weight average molecular weight is an average molecular weight measured by GPC analysis and converted into standard polystyrene.

[0050] In this embodiment, a combination of a polymerizable oligomer and a polymerizable monomer may be used as the resin forming the resin layer 36. The polymerizable oligomer may be a polyfunctional urethane (meth)acrylate oligomer. Preferably, the polymerizable oligomer may be a polyfunctional urethane acrylate oligomer. The polymerizable monomer may be a polyfunctional polymerizable monomer. Preferably, the polymerizable monomer may be a polyfunctional (meth)acrylate monomer. More preferably, the polymerizable monomer may be a polyfunctional acrylate monomer. The mixing ratio of the polymerizable oligomer and the polymerizable monomer can be adjusted appropriately depending on the required properties.

[0051] The resin composition used in the resin layer 36 may contain other components in addition to the above-mentioned resins depending on the desired performance, etc. For example, the resin composition used in the resin layer 36 may contain a monofunctional (meth)acrylate for the purpose of reducing its viscosity, etc. These monofunctional (meth)acrylates may be used alone or in combination of two or more types.

[0052] Furthermore, when the resin is an ultraviolet-curable resin that is cured by ultraviolet light, it may contain additives such as a photopolymerization initiator and a photopolymerization accelerator. As the photopolymerization initiator, for example, one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyl dimethyl ketal, benzoyl benzoate, α-acyloxime ester, thioxanthones, etc. may be used. The photopolymerization accelerator can reduce polymerization inhibition by air during curing and increase the curing rate. As the photopolymerization accelerator, for example, one or more selected from p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, etc. may be used.

[0053] Particles 38 function as a wrinkle-forming agent for imparting a specific wrinkled structure to textured surface 32. In conventional techniques for forming a wrinkled textured surface on a resin surface using excimer light or the like, it was difficult to precisely control the shape of the wrinkled structure of the textured surface. After extensive research into this issue, the present inventors found that the shape of the wrinkled structure of textured surface 32 can be controlled by further adding particles 38 to the resin composition for forming matte layer 30.

[0054] A technique for forming a matte layer by adding particles such as silica to a resin layer without a wrinkled structure has been known. In this technique, particles protruding from the surface of the resin layer form irregularities on the surface, which provide a matte effect. In contrast, in the present embodiment, the irregularities on the irregular surface 32 are realized by the wrinkled structure. The particles 38 of this embodiment are not intended to form the irregularities on the irregular surface 32 themselves. In this respect, the particles 38 of this embodiment are essentially different from particles added to a resin layer without a wrinkled structure. The present inventors speculate that when a resin composition is irradiated with excimer light or the like, as in the manufacturing method described below, the particles 38 act as the starting point for the formation of the convex and / or concave portions that constitute the wrinkled structure. This is believed to make it possible to impart a shape to the wrinkled structure that was difficult to achieve using conventional techniques. In this embodiment, the inclusion of particles 38 in the matte layer 30 allows the irregular surface 32 to have a maximum height Rz of 6 μm or less and an average length RSm of 45 μm or less. Such particles 38 will be described below.

[0055] The particles 38 may be, for example, organic particles or inorganic particles. Examples of organic materials that may be used for the organic particles include polymethyl methacrylate, acrylic-styrene copolymer resin, melamine resin, polycarbonate, polystyrene, polyvinyl chloride resin, benzoguanamine-melamine-formaldehyde condensate, silicone, fluorine-based resin, and polyester-based resin. Examples of inorganic materials that may be used for the inorganic particles include silica, alumina, calcium carbonate, aluminosilicate, and barium sulfate. Among these, silica is preferably used for the inorganic particles. The shape of the particles 38 may be, for example, spherical, polyhedral, scaly, or irregular.

[0056] The average particle diameter of the particles 38 may be 1 μm or more. Preferably, the average particle diameter of the particles 38 may be 1.3 μm or more. More preferably, the average particle diameter of the particles 38 may be 1.5 μm or more. Even more preferably, the average particle diameter of the particles 38 may be 1.8 μm or more. The average particle diameter of the particles 38 may be 20 μm or less. Preferably, the average particle diameter of the particles 38 may be 15 μm or less. Even more preferably, the average particle diameter of the particles 38 may be 10 μm or less. In this specification, the average particle diameter of the particles 38 is the average particle diameter (arithmetic mean diameter) of particle diameters measured for 100 randomly selected non-aggregates of the particles 38 when a cross section of the matte layer 30 in the thickness direction is observed using a scanning electron microscope (SEM) at an acceleration voltage of 3.0 kV and a magnification of 50,000 times. The particle diameter is the value measured by sandwiching the cross section of particle 38 between any two parallel lines and measuring the distance between the two lines that is the maximum distance between the two lines.

[0057] The plurality of particles 38 may include particles 38 having a maximum dimension equal to or greater than half the thickness of the resin layer 36. The present inventors' studies have revealed that the shape of the wrinkle structure of the textured surface 32 can be more appropriately controlled when the plurality of particles 38 include particles 38 having a maximum dimension equal to or greater than half the thickness of the resin layer 36. Preferably, the plurality of particles 38 may include particles 38 having a maximum dimension equal to or greater than the thickness of the resin layer 36. More preferably, the plurality of particles 38 may include particles 38 having a maximum dimension equal to or greater than 1.5 times the thickness of the resin layer 36. Even more preferably, the plurality of particles 38 may include particles 38 having a maximum dimension equal to or greater than twice the thickness of the resin layer 36. Furthermore, the maximum dimension of the particles 38 may be equal to or less than 10 times the thickness of the resin layer 36. In this case, the thickness of the resin layer 36 is sufficiently secured relative to the maximum dimension of the particles 38. This allows the resin layer 36 to fully function as a binder. Therefore, the particles 38 are appropriately held by the resin layer 36. Preferably, the maximum dimension of the particles 38 may be no greater than eight times the thickness of the resin layer 36 .

[0058] The maximum dimension of particle 38 is the dimension of particle 38 measured by observing a cross section of matte layer 30 in the thickness direction using a scanning electron microscope (SEM) at an accelerating voltage of 3.0 kV and a magnification of 50,000 times. The maximum dimension of particle 38 is the value measured by sandwiching the cross section of particle 38 between two parallel lines, and then measuring the distance between the two lines that is the longest. Depending on the position of the cross section of particle 38, the maximum dimension of particle 38 measured as described above may differ from the true maximum dimension of particle 38. However, the maximum dimension of particle 38 measured as described above will never be larger than the true maximum dimension of particle 38. Therefore, it can be assumed that the true maximum dimension of particle 38 is equal to or larger than the maximum dimension of particle 38 measured as described above.

[0059] The content of particles 38 may be 0.5 parts by mass or more relative to 100 parts by mass of the resin forming resin layer 36. Preferably, the content of particles 38 may be 0.75 parts by mass or more. More preferably, the content of particles 38 may be 1 part by mass or more. Even more preferably, the content of particles 38 may be 1.2 parts by mass or more. The content of particles 38 may be 25 parts by mass or less relative to 100 parts by mass of the resin forming resin layer 36. Preferably, the content of particles 38 may be 15 parts by mass or less. Even more preferably, the content of particles 38 may be 10 parts by mass or less. Even more preferably, the content of particles 38 may be 7.5 parts by mass or less. Even more preferably, the content of particles 38 may be 6 parts by mass or less.

[0060] Next, an example of a method for manufacturing the decorative sheet 10 of this embodiment will be described. First, a laminate of the substrate 12, the design layer 20, the adhesive layer 14, the transparent resin layer 16, and the primer layer 18 is prepared. Next, a mixture of particles 38 and a resin composition that will later become the resin layer 36 is placed on the primer layer 18 of this laminate. The mixture may be applied to the primer layer 18 in a fluid state, for example. The mixture may be applied by gravure printing, bar coating, roll coating, reverse roll coating, comma coating, or the like. Alternatively, the mixture may be formed into a sheet and then attached to the primer layer 18.

[0061] Next, the resin composition is irradiated with light having a wavelength of more than 380 nm to pre-cure the entire resin composition. Preferably, the wavelength of this light may be 385 nm or more and 400 nm or less. Note that this pre-cure step is not an essential step and may be omitted.

[0062] The surface of the resin composition is then irradiated with light having a wavelength of 100 nm or more and 380 nm or less. This forms a wrinkled structure on the surface of the resin composition. The mechanism by which this wrinkled structure is formed is presumed to be as follows. When the surface of the resin composition is irradiated with light having a wavelength of 100 nm or more and 380 nm or less, the light energy penetrates only the surface portion due to the short wavelength of the light, and the light energy does not reach the layers below. At this time, only the surface portion of the resin composition begins to harden. As a result, only the surface undergoes cure shrinkage, and a wrinkled structure is formed on the surface of the resin composition. It is believed that only the portion of the resin composition within a certain thickness from the surface is in a hardened state. Furthermore, it is believed that at this time, particles 38 function like a nucleus that triggers the formation of the wrinkled structure. Therefore, it is presumed that the resin on the surface portion of the resin composition gathers around particles 38, forming the convex and concave portions of the wrinkled structure.

[0063] Examples of light having a wavelength of 100 nm or more and 380 nm or less include "excimer light," which includes light in the ultraviolet wavelength range from excited dimers, i.e., excimers, formed by discharge of rare gases such as Ar, Kr, Xe, and Ne, halides of rare gases such as halogens F, Cl, I, and Br, or mixed gases thereof. The wavelength and source of the excimer light may be, for example, 126 nm light emitted from the excimer of Ar (hereinafter abbreviated as "126 nm (Ar)"), 146 nm (Kr), 157 nm (F), 172 nm (Xe), 193 nm (ArF), 222 nm (KrCl), 247 nm (KrF), 308 nm (XeCl), or 351 nm (XeF). The excimer light may be spontaneous emission light or highly coherent laser light due to stimulated emission. Discharge lamps that emit such light are also called "excimer lamps." Excimer light has a single wavelength peak and a narrower half-width wavelength than ordinary ultraviolet light (e.g., ultraviolet light emitted from metal halide lamps, mercury lamps, etc.). Using such excimer light stabilizes wrinkle formation and improves the matte effect stably.

[0064] The wavelength of the light irradiated onto the surface of the resin composition may be 120 nm or more. Preferably, the wavelength of the light may be 140 nm or more. More preferably, the wavelength of the light may be 150 nm or more. Even more preferably, the wavelength of the light may be 155 nm or more. The wavelength of the light irradiated onto the surface of the resin composition may be 320 nm or less. Preferably, the wavelength of the light may be 300 nm or less. Even more preferably, the wavelength of the light may be 250 nm or less. Even more preferably, the wavelength of the light may be 200 nm or less. Even more preferably, the wavelength of the light may be 172 nm (Xe2).

[0065] When the light irradiated onto the surface of the resin composition has a wavelength of 172 nm, the integrated light intensity of the light is 0.1 mJ / cm 2 Preferably, the integrated light amount is 0.5 mJ / cm 2More preferably, the integrated light amount is 1 mJ / cm 2 The integrated light amount of the light irradiated onto the surface of the resin composition may be 300 mJ / cm or more. 2 Preferably, the integrated light amount is 100 mJ / cm 2 More preferably, the integrated light amount is 50 mJ / cm 2 It may be the following:

[0066] When the light irradiated onto the surface of the resin composition has a wavelength of 172 nm, the power density of the light may be 0.001 W / cm or more. Preferably, the power density may be 0.01 W / cm or more. More preferably, the power density may be 0.02 W / cm or more. The power density of the light irradiated onto the surface of the resin composition may be 1 W / cm or less. Preferably, the power density may be 0.5 W / cm or less. More preferably, the power density may be 0.1 W / cm or less.

[0067] The oxygen concentration when irradiating the surface of the resin composition with light may be 1000 ppm or less. Preferably, the oxygen concentration may be 750 ppm or less. More preferably, the oxygen concentration may be 500 ppm or less. Still more preferably, the oxygen concentration may be 300 ppm or less.

[0068] As described above, the surface of the resin composition is irradiated with light having a wavelength of 100 nm or more and 380 nm or less, and then the resin composition is irradiated with light having a wavelength longer than the wavelength of the light irradiated with the light. This causes curing to proceed in the depthwise distant portion of the resin composition from the surface, resulting in the entire resin composition being cured. At this time, the formation of a wrinkle structure further progresses due to the difference in the degree of curing progress between the surface portion of the resin composition and the depthwise distant portion of the resin composition. For example, ultraviolet (UV) light may be used as the light used to completely cure the resin composition. Furthermore, other ionizing radiation, such as an electron beam (EB), may be used instead of ultraviolet light to completely cure the resin composition.

[0069] The decorative sheet 10 of this embodiment comprises a matte layer 30 having an uneven surface 32, the matte layer 30 including a resin layer 36 and a plurality of particles 38, the uneven surface 32 having a wrinkled structure, the maximum height Rz of the uneven surface 32 as specified in JIS B0601:2013 being 6 μm or less, and the average length RSm of the uneven surface 32 as specified in JIS B0601:2013 being 45 μm or less.

[0070] In this decorative sheet 10, the average length RSm is 45 μm or less, so that the uneven surface 32 has a fine wrinkle structure. Therefore, the gloss on the surface of the matte layer 30 is effectively reduced. That is, the uneven surface 32 fully exhibits a matte effect. Furthermore, the maximum height Rz is 6 μm or less, so that the depth of the recesses as seen from the tops of the protrusions of the uneven surface 32 is reduced. This makes it easier to remove contaminants that have entered the recesses of the uneven surface 32. Therefore, the wiping ability of the uneven surface 32 is effectively improved. In particular, it was not previously known that adjusting the maximum height Rz of an uneven surface having a wrinkle structure makes it easier to remove contaminants that have entered the recesses of the uneven surface. Therefore, the technology of this embodiment, which improves the wiping ability of the uneven surface 32 by setting the maximum height Rz of the uneven surface 32 having a wrinkle structure to 6 μm or less, makes an extremely significant technical contribution over the prior art.

[0071] In the decorative sheet 10 of this embodiment, the plurality of particles 38 include particles 38 having a maximum dimension that is equal to or greater than half the thickness of the resin layer 36 .

[0072] With such a decorative sheet 10, the particles 38 that serve as the starting points for forming the convex and concave portions in the wrinkled structure have a large maximum size, so the shape of the wrinkled structure of the uneven surface 32 can be more appropriately controlled.

[0073] An example of an experiment conducted by the present inventors will be described below. Note that the embodiments of the present disclosure are not limited to the results of the following experiment.

[0074] Samples 1 to 10 were prepared under the following conditions. Photographs of the matte layer surface were taken for each sample. Figures 2 to 10 are photographs of the matte layer surface for each sample. Furthermore, the maximum height Rz, average length RSm, and surface glossiness were measured for each sample. Furthermore, the surface wiping properties were evaluated for each sample. Table 1 shows the conditions for each sample, the measured maximum height Rz and average length RSm values, glossiness, and wiping property evaluation, as well as the drawing number of the corresponding surface photograph.

[0075] Sample 1 A photopolymerization initiator was added to 100 parts by mass of a bifunctional monomer to prepare a resin composition, and 3 parts by mass of silica particles with an average particle size of 8 μm were added to this resin composition to prepare an ink. An adhesive was applied to a polypropylene sheet and dried, and the ink was applied to the adhesive and dried. The ink coating thickness was 1 μm (when dry). The ink was pre-cured by irradiating it with ultraviolet light using a UV-LED light source. The cumulative light dose was 30 mJ / cm 2 It was. Next, the ink was irradiated with excimer light (wavelength 172 nm) from an excimer lamp to cure the surface of the resin composition. The cumulative light dose was 5 mJ / cm 2 It was. The ink was then irradiated with electron beams to cure the entire resin composition, thereby forming a matte layer from the ink. The acceleration voltage was 125 kV and the irradiation dose was 50 kGy (5 Mrad).

[0076] Sample 2 The same procedure as in Sample 1 was followed, except that the coating thickness of the resin composition was 4 μm.

[0077] Sample 3 The same procedure as in Sample 1 was followed, except that the coating thickness of the resin composition was 10 μm.

[0078] Sample 4 The same as Sample 1 was used except that the average particle size of the silica particles was 2 μm.

[0079] Sample 5 The same procedures as in Sample 1 were carried out except that the coating thickness of the resin composition was 4 μm and the average particle size of the silica particles was 2 μm.

[0080] Sample 6 The same procedure was followed as in Sample 1, except that the monomer contained in the resin composition was changed to a trifunctional monomer.

[0081] Sample 7 The same procedure as in Sample 6 was followed, except that the coating thickness of the resin composition was 4 μm.

[0082] Sample 8 The same as Sample 6 was used except that the average particle size of the silica particles was 2 μm.

[0083] Sample 9 The same procedures as in Sample 6 were carried out except that the coating thickness of the resin composition was 4 μm and the average particle size of the silica particles was 2 μm.

[0084] Sample 10 The same procedures as in Sample 6 were carried out except that the coating thickness of the resin composition was 10 μm and the average particle size of the silica particles was 2 μm.

[0085] The maximum height Rz was measured using a shape analysis laser microscope (Keyence Corporation, VK-X150 (controller) / VK-X160 (measuring unit)) in accordance with JIS B0601:2013. The maximum height Rz was measured at 20 locations on the matte layer, and the arithmetic mean value was used as the maximum height Rz value for each sample.

[0086] The average length RSm was measured using a shape analysis laser microscope (Keyence Corporation, VK-X150 (controller) / VK-X160 (measuring unit)) in accordance with JIS B0601:2013. The average length RSm was measured at 20 locations on the matte layer, and the arithmetic mean value was used as the average length RSm value for each sample.

[0087] The gloss is the 60° specular gloss Gs(60) measured in accordance with JIS Z8741:1997 using a micro-tri-gloss (manufactured by BYK Gardner).

[0088] Wiping properties were evaluated in accordance with the JAS Staining A Test. A 10 mm-wide line was drawn on the surface of the matte layer using a marking pen specified in JIS S6037:2006 in black oil-based ink. After leaving the line for 4 hours, the line was wiped off with a cloth soaked in solvent. Table 1 shows the wiping properties rated A to C. A rating was given for cases where the oil-based ink was not visible to the naked eye after wiping. A rating was given for cases where the oil-based ink was slightly visible to the naked eye after wiping, but within an acceptable range. A rating was given for cases where the oil-based ink was clearly visible to the naked eye after wiping.

[0089] [Table 1]

[0090] As shown in Table 1, Samples 1 to 9, which have an average length RSm of 45 μm or less, have a gloss level of 5 or less, demonstrating a sufficient matte effect. Samples 1, 2, 4, and 6 to 10, which have a maximum height Rz of 6 μm or less, have wiping properties rated A or B, demonstrating good wiping properties. Samples 6, 8, and 10, which have a maximum height Rz of 3 μm or less, have wiping properties rated A, demonstrating even better wiping properties.

[0091] Furthermore, comparing Samples 1 to 3, it can be seen that the smaller the resin layer thickness relative to the particle diameter, i.e., the larger the particle diameter relative to the resin layer thickness, the smaller the maximum height Rz and average length RSm. Also, comparing the photographs of Samples 1 to 3, it can be seen that the larger the particle diameter relative to the resin layer thickness, the more finely wrinkled the structure formed. Furthermore, it can be seen that the larger the particle diameter relative to the resin layer thickness, the better the evaluation of wiping performance. This is also true for comparing Samples 4 and 5, and for comparing Samples 6 and 7. Therefore, these experimental results show that the larger the particle diameter relative to the resin layer thickness, the more finely wrinkled the structure formed and the better the wiping performance.

[0092] Although one embodiment has been described with reference to specific examples, the above-described specific examples do not limit the present invention. The above-described embodiment can be implemented with various other specific examples, and various omissions, substitutions, changes, additions, etc. can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0093] 10 Decorative Sheet 12 Base material 14 Adhesive layer 16 Transparent resin layer 18 Primer layer 20 Design Layer 22 Colored layer 24 Picture layer 30 Matte layer 32 Uneven surface 34 Back side 36 Resin layer 38 particles

Claims

1. A decorative sheet provided with a matte layer having an uneven surface, the matte layer includes a resin layer and a plurality of particles, the uneven surface has a wrinkled structure, The arithmetic mean value of the maximum height Rz defined in JIS B0601:2013 at any 20 points on the uneven surface is 6 μm or less, The decorative sheet has an average length RSm of 45 μm or less on the uneven surface as defined in JIS B0601:2013.

2. the arithmetic mean value is 3 μm or less, 2. The decorative sheet according to claim 1, wherein said average length RSm is 40 μm or less.

3. 3. The decorative sheet according to claim 1, wherein said plurality of particles include particles having a maximum dimension equal to or greater than half the thickness of said resin layer.

4. The decorative sheet according to claim 3 , wherein said plurality of particles includes particles having a maximum dimension equal to or greater than the thickness of said resin layer.

5. The decorative sheet according to any one of claims 1 to 4, wherein the average particle size of the plurality of particles is 1 µm or more.

6. The decorative sheet according to any one of claims 1 to 5, wherein the matte layer is provided over the entire surface of one side of the decorative sheet.

7. The decorative sheet according to any one of claims 1 to 6, wherein the 60° specular gloss of the textured surface, as defined in JIS Z8741:1997, is 5 or less.

8. A decorative material comprising an adherend and the decorative sheet according to any one of claims 1 to 7 provided on the adherend.

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