Decorative piece

Abstract

A decorative sheet with excellent water resistance, low gloss and scratch resistance is provided. A decorative sheet (1) comprises: a raw material layer (2) containing paper, a pigment-containing layer (3) disposed on the raw material layer (2) and containing a cured product of a first ionizing radiation curable resin and a pigment, and a surface protective layer (4) disposed on the pigment-containing layer (3), wherein the surface protective layer (4) contains a cured product of a second ionizing radiation curable resin as a resin cured product, and has an uneven structure on its surface comprising a plurality of ridges protruding in a ridge shape, wherein the ratio of the average length RSm of the roughness curve element of the uneven structure to the arithmetic mean roughness Ra, RSm / Ra, is in the range of 10 to 800.

Description

Technical Field

[0001] This invention relates to decorative sheets. Background Technology

[0002] Decorative sheets are used to enhance the design and durability of interior and exterior decorative materials such as doors, windows, furniture, building materials, and flooring materials. Decorative sheets are generally used as decorative panels that are glued to the surface of substrates such as wood, wood-based panels, metal panels, non-combustible boards, paper substrates, and resin substrates using adhesives or the like.

[0003] Design elements can be incorporated, such as using various printing techniques to create patterns like wood grain or stone texture. Decorative pieces are sometimes preferred in solid colors without patterns. The choice of whether or not to have patterns, and the type of patterns, varies greatly depending on the intended use and personal preference.

[0004] In the design of decorative panels, the surface gloss is also important. As decorative panels, depending on the purpose and preference, a variety of options are available, ranging from high gloss like a mirror to low gloss with no reflection at all.

[0005] In addition, as mentioned earlier, another important function of decorative panels, alongside design features, is to provide durability. Durability refers to a comprehensive evaluation of resistance to damage, staining, and whether these properties can be ensured over a long period. Requirements vary depending on the environment and conditions in which the decorative panels are used, but high-performance decorative panels are always required.

[0006] To enhance durability, a protective coating is typically formed on the outermost surface of the decorative piece. Additionally, to adjust the gloss level, particularly to achieve a low-gloss finish, a gloss modifier (matte additive) is usually added to the protective coating.

[0007] Furthermore, since decorative panels are typically processed by cutting or bending in order to form decorative materials such as decorative panels, it is preferable to have processability that can withstand these processes.

[0008] Thus, as a decorative sheet that takes into account design (low gloss), scratch resistance, and stain resistance, there is, for example, the decorative sheet described in Patent Document 1.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2019-119138 Summary of the Invention

[0012] The purpose of this invention is to provide decorative sheets with excellent water resistance, low gloss, and scratch resistance.

[0013] According to one aspect of the present invention, a decorative sheet is provided, comprising: a raw material layer containing paper, a pigment-containing layer disposed on the raw material layer and containing a cured product of a first ionizing radiation-curable resin and a pigment, and a surface protective layer disposed on the pigment-containing layer, wherein the surface protective layer contains a cured product of a second ionizing radiation-curable resin as a resin cured product, and has an uneven structure on its surface comprising a plurality of ridges each protruding in a ridge shape, wherein the ratio of the average length RSm of the roughness curve element of the uneven structure to the arithmetic mean roughness Ra, RSm / Ra, is in the range of 10 or more and 800 or less.

[0014] According to other aspects of the invention, a decorative sheet relating to the above aspects is provided, wherein the first ionizing radiation-curable resin contains acrylate.

[0015] According to yet another aspect of the invention, a decorative sheet relating to any of the above aspects is provided, wherein the thickness of the pigment-containing layer is in the range of 0.5 μm to 20 μm.

[0016] According to yet another aspect of the invention, a decorative sheet relating to any of the above aspects is provided, wherein the thickness of the surface protective layer is in the range of 2 μm to 20 μm.

[0017] According to yet another aspect of the invention, a decorative sheet is provided that relates to any of the above aspects, wherein the combined thickness of the pigment-containing layer and the surface protective layer is in the range of 3 μm to 40 μm.

[0018] According to yet another aspect of the invention, a decorative sheet is provided that relates to any of the above aspects, wherein, when the mass of the first ionizing radiation-curable resin is set to 100 parts by mass, the mass of the pigment is 3 parts by mass or more and 50 parts by mass or less.

[0019] According to yet another aspect of the invention, a decorative sheet relating to any of the above aspects is provided, wherein the pigment is titanium oxide.

[0020] According to yet another aspect of the invention, a decorative sheet relating to any of the above aspects is provided, wherein the second ionizing radiation-curable resin contains acrylate.

[0021] According to yet another aspect of the invention, a decorative sheet relating to the above aspects is provided, wherein the second ionizing radiation-curable resin contains an acrylate with two or more functions comprising a repeating structure.

[0022] According to another aspect of the present invention, a decorative sheet relating to the above aspects is provided, wherein the repeating structure is repeated three times or more.

[0023] According to another aspect of the invention, a decorative sheet relating to the above aspects is provided, wherein the number of repetitions of the repeating structure is 30 or less.

[0024] According to another aspect of the invention, a decorative sheet relating to the above aspects is provided, wherein the surface protective layer further contains particles with an average particle size of less than 10 μm.

[0025] According to another aspect of the invention, a decorative sheet relating to the above aspects is provided, wherein, when the mass of the second ionizing radiation-curable resin is set to 100 parts by mass, the mass of the particles is in the range of 0.5 parts by mass to 20 parts by mass.

[0026] According to another aspect of the invention, a decorative sheet relating to the above aspects is provided, wherein the gloss of the surface protective layer is 20.0 or less.

[0027] According to another aspect of the present invention, a decorative material is provided, comprising: a decorative sheet according to any of the above aspects, and a substrate for attaching the decorative sheet.

[0028] According to another aspect of the present invention, a method for manufacturing a decorative sheet is provided, comprising: forming a first coating film containing pigment and a first ionizing radiation-curable resin on a paper-containing raw material layer; forming a second coating film containing a second ionizing radiation-curable resin as resin on the first coating film; and irradiating the second coating film with ionizing radiation or ultraviolet light to completely cure the second coating film.

[0029] According to another aspect of the present invention, a method for manufacturing a decorative sheet according to the above aspects is provided, wherein the complete curing of the second coating film includes: an irradiation step of irradiating the second coating film with light having a wavelength of 200 nm or less; and then an irradiation step of irradiating the second coating film with ionizing radiation or ultraviolet light having a wavelength longer than the light irradiated in the irradiation step.

[0030] According to the present invention, a decorative sheet with excellent water resistance, low gloss and scratch resistance is provided. Attached Figure Description

[0031] [ Figure 1 ] Figure 1 This is a cross-sectional view of a decorative material comprising a decorative sheet according to one embodiment of the present invention.

[0032] [ Figure 2 ] Figure 2 yes Figure 1 A cross-sectional view of the surface protective layer contained in the decorative piece.

[0033] [ Figure 3 ] Figure 3This is a microscope image of the surface protective layer contained in a decorative sheet, which is an example of the present invention.

[0034] [ Figure 4 ] Figure 4 It is Figure 2 A cross-sectional view showing a portion of the surface protective layer. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are more specific embodiments of any of the above aspects. The matters described below may be incorporated into the above aspects individually or in combination.

[0036] Furthermore, the embodiments shown below illustrate configurations for embodying the technical concept of the present invention. The technical concept of the present invention is not limited by the material, shape, or structure of the constituent components described below. Various modifications can be made to the technical concept of the present invention within the scope defined by the claims.

[0037] It should be noted that for elements with the same or similar functions, the same reference numerals will be used in the accompanying drawings below, and repeated descriptions will be omitted. Furthermore, the drawings are schematic; the relationship between dimensions in one direction and dimensions in other directions, as well as the relationship between the dimensions of one component and the dimensions of other components, may differ from the actual situation.

[0038] <1> Decorative materials and decorative panels

[0039] Figure 1 This is a cross-sectional view of a decorative material comprising a decorative sheet according to one embodiment of the present invention. Figure 2 yes Figure 1 A cross-sectional view of the surface protective layer contained in the decorative piece. Figure 3 This is a microscope image of the surface protective layer contained in a decorative sheet, which is an example of the present invention. Figure 4 It is Figure 2 A cross-sectional view showing a portion of the surface protective layer.

[0040] It should be noted that, Figure 2 and Figure 4 The cross-section shown is along the thickness direction of the surface protective layer. Additionally, Figure 3 The microscope images are planar images obtained using a laser microscope (Olympus Corporation OLS-4000).

[0041] Figure 1The decorative material 11 shown includes a substrate B and a decorative sheet 1 adhered thereto. Here, the decorative material 11 is a decorative panel. The decorative panel can be flat, curved, or folded. The decorative material 11 can also have shapes other than flat.

[0042] Here, substrate B is a board material. The board material can be, for example, wood-based panels, inorganic panels, metal panels, or composite panels made of multiple materials. Substrate B can also have shapes other than those of a board.

[0043] Decorative sheet 1 includes a raw material layer 2, a pigment-containing layer 3, and a surface protective layer 4. The pigment-containing layer 3 and the surface protective layer 4 are sequentially disposed on the side of the raw material layer 2 opposite to the side facing the substrate B, starting from the raw material layer 2 side. Decorative sheet 1 may also include one or more other layers such as a transparent resin layer.

[0044] The elements included in decorative piece 1 will be described in turn below.

[0045] <1.1> Raw Material Layer

[0046] The base material layer 2 contains paper. The base material layer 2 can have a single-layer structure or a multi-layer structure. According to one example, the entire base material layer 2 is made of paper. According to other examples, the base material layer 2 has a multi-layer structure, with at least the outermost layer facing the surface protective layer 4 being made of paper. In the case where the base material layer 2 has a multi-layer structure, in addition to one or more layers made of paper, it may also include one or more layers made of materials other than paper.

[0047] The paper may be, for example, thin sheet paper, resin-blended paper, titanium paper, resin-impregnated paper, flame-retardant paper, or inorganic paper. The paper contained in the base material layer 2 may contain, for example, cellulose fibers. The base material layer 2 may have various forms, such as film, sheet, board, or cast molded body.

[0048] <1.2> Pigment contains layers

[0049] The pigment-containing layer 3 is, for example, a continuous film covering the entire surface of the base material layer 2. The pigment-containing layer 3 can function as a masking layer for the substrate B or the base material layer 2. Additionally, the pigment-containing layer 3 can also function as a planarization layer.

[0050] The pigment-containing layer 3 contains a cured product of a first ionizing radiation-curable resin and a pigment. According to one example, the pigment-containing layer 3 contains only the first ionizing radiation-curable resin as a resin curing product. According to other examples, the pigment-containing layer 3 contains both a first ionizing radiation-curable resin and a thermosetting resin as resin curing products. Here, "ionizing radiation" refers to a beam of charged particles such as an electron beam. The first ionizing radiation-curable resin is cured by irradiation with ionizing radiation. Alternatively, the first ionizing radiation-curable resin can also be cured by irradiation with ultraviolet light. The thermosetting resin will be described later.

[0051] When the mass of the pigment-containing layer 3 is set to 100 parts by mass, the mass of the cured product of the first ionizing radiation curable resin contained in the pigment-containing layer 3 is preferably 50 parts by mass or more and 97 parts by mass or less, more preferably 60 parts by mass or more and 95 parts by mass or less.

[0052] As the first ionizing radiation curable resin, various known resins such as monomers or commercially available oligomers can be used, for example, (meth)acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, or epoxy resins. The first ionizing radiation curable resin can be either a water-based resin or a non-water-based (organic solvent-based) resin. The first ionizing radiation curable resin can also be solvent-free. Preferably, the first ionizing radiation curable resin contains acrylate.

[0053] According to one example, the first ionizing radiation-curable resin is an aqueous dispersion or emulsion comprising at least one of urethane acrylate and polyurethane resin. As such a dispersion or emulsion, for example, a substance comprising a resin having acryloyl groups can be used.

[0054] According to other examples, the first ionizing radiation curable resin is a mixture of acrylate and methacrylate. When using the above mixture as the first ionizing radiation curable resin, high adhesion between the pigment-containing layer 3 and the surface protective layer 4 can be achieved.

[0055] The cured product of the first ionizing radiation-curable resin preferably contains one or more bonds selected from the group consisting of urethane bonds, carbonate bonds, and amide bonds.

[0056] Furthermore, as described above, the pigment containing layer 3 may also contain a first ionizing radiation-curable resin and a thermosetting resin as resin curing products. According to one example, the thermosetting resin comprises one or more of an aqueous urethane dispersion, an aqueous epoxy dispersion, and an aqueous polyamine dispersion. As the aqueous dispersion, for example, a substance containing a carboxylic acid derivative with a polycarbonate backbone can be used.

[0057] It should be noted that when an aqueous dispersion or emulsion is used as at least one of the first ionizing radiation curable resin and thermosetting resin, surfactant may remain in the pigment-containing layer 3 as a trace of it.

[0058] As described below, the additives added to the first ionizing radiation-curable resin are used to improve the function of the final product, and are, for example, one or more of an antibacterial agent, a mildew inhibitor, an ultraviolet absorber, and a light stabilizer. The total amount of additives is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, relative to 100 parts by mass of the first ionizing radiation-curable resin.

[0059] The pigment includes at least one of white pigments and colored pigments. Examples of pigments that can be used include inorganic pigments such as carbon black, titanium dioxide (titanium white), zinc white, carmine, chrome yellow, dark blue, and cadmium red; organic pigments such as azo pigments, lake pigments, anthraquinone pigments, phthalocyanine pigments, isoindolinone pigments, and dioxazine pigments; or mixtures thereof. Titanium dioxide is preferred as the pigment.

[0060] The average particle size of the pigment is preferably in the range of 50 nm to 5 μm, more preferably in the range of 100 nm to 1 μm. It should be noted that, for the particles of the surface protective layer 4, this average particle size is the median particle size (D50) described later.

[0061] The amount of pigment, relative to 100 parts by weight of the first ionizing radiation curable resin, is preferably in the range of 3 to 50 parts by weight, more preferably in the range of 5 to 30 parts by weight. When the amount of pigment is small, the effect of masking the substrate B or the original material layer 2, i.e., the masking performance, is easily reduced. For example, when the above amount is less than 3 parts by weight, it is difficult to achieve high masking performance. In addition, when the above amount is greater than 50 parts by weight, the uniformity of the coating film may sometimes decrease.

[0062] The thickness of the pigment-containing layer 3 is preferably in the range of 0.5 μm to 20 μm, more preferably in the range of 2 μm to 15 μm, and even more preferably in the range of 3 μm to 10 μm. When the thickness of the pigment-containing layer 3 is small, it is difficult to achieve high concealment. When the thickness of the pigment-containing layer 3 is large, the processability of the decorative sheet 1 is reduced, and it is prone to whitening during bending processing.

[0063] <1.4> Surface Protective Layer

[0064] A surface protective layer 4 is disposed on the pigment-containing layer 3. Here, the surface protective layer 4 covers the entire upper surface of the pigment-containing layer 3.

[0065] The specular gloss GS (60°) of the surface protective layer 4 is preferably 20.0 or less, more preferably 18 or less, and even more preferably 15 or less. According to one example, the specular gloss GS (60°) of the surface protective layer 4 is 0.5 or more. Here, "spectral gloss GS (60°)" refers to the specular gloss measured using a gloss meter at an incident angle of 60 degrees according to ISO 2813. It should be noted that the specular gloss GS (60°) is sometimes indicated by adding "%" after the numerical value, but the "%" is omitted here.

[0066] An uneven structure is provided on the surface of the surface protective layer 4. The uneven structure provided on the upper surface of the surface protective layer 4 serves to reduce the specular gloss GS (60°) of the surface protective layer 4.

[0067] Here, the surface of the surface protective layer 4 is provided with a concave-convex structure comprising multiple ridge-shaped portions, each protruding in a ridge-like manner. That is, as shown... Figure 2 and Figure 4 As shown, the surface protective layer 4 includes: a thin layer, namely a core 4A, having a flat upper surface; and a plurality of ridges 4B each protruding in a ridge shape from the upper surface of the core 4A.

[0068] In this disclosure, the ridge portion 4B refers, for example, to the portion extending from the lowest point to the highest point of the protrusion provided on the surface of the surface protective layer 4, and the core portion 4A refers to the portion of the surface protective layer 4 excluding the ridge portion 4B. Furthermore, "ridge" refers to a convex shape extending in a linear form in a plan view.

[0069] The ridge 4B can be curved or straight in a plan view, but from the viewpoint of fingerprint resistance of the decorative piece 1 surface, it is preferred. Figure 3 The example is a curved shape. It should be noted that, as described later, the surface protective layer 4 with the ridge portion 4B can be formed, for example, by irradiating the surface of a coating containing a second ionizing radiation-curable resin with light of a specific wavelength, causing the cured film generated on the surface of the coating to expand inward.

[0070] The ratio of the average length RSm of the roughness curve elements of the uneven structure on the upper surface of the surface protective layer 4 to the arithmetic mean roughness Ra, RSm / Ra, is in the range of 10 to 800. The RSm / Ra ratio is preferably in the range of 10 to 600, more preferably in the range of 10 to 500, even more preferably in the range of 10 to 400, even more preferably in the range of 50 to 400, and even more preferably in the range of 50 to 350. When the RSm / Ra ratio decreases, the spacing between the protrusions becomes smaller. As a result, it becomes difficult to wipe away dirt adhering to the surface of the decorative piece 1, and the stain resistance decreases. When the RSm / Ra ratio increases, the spacing between the protrusions becomes larger, and the effect of the uneven structure in reducing the specular gloss GS (60°) of the surface protective layer 4 becomes smaller.

[0071] The RSm / Ra ratio is preferably 80 or higher. As the RSm / Ra ratio increases, the spacing between the protrusions increases, and the affinity of water or detergent (water containing surfactants or alcohols) for the upper surface of the surface protective layer 4 increases. If the decorative sheet 1 has such surface properties as the surface protective layer 4, it is easy to wipe away dirt with water or detergent even if the surface is contaminated.

[0072] The RSm / Ra ratio is preferably 100 or higher. If the RSm / Ra ratio is within this range, it is possible to make contact between a commercially available cleaning sponge and the boundary of the protrusion on the upper surface of the surface protective layer 4 and the area theren. Therefore, even if the surface of the decorative piece 1 is contaminated, it is easy to wipe away dirt with a commercially available cleaning sponge.

[0073] Here, the arithmetic mean roughness Ra and the average length RSm of the roughness curve elements are measured values ​​when measured using a line roughness meter (according to JIS B0601:2013).

[0074] The arithmetic mean roughness Ra is preferably in the range of 0.2 μm to 10.0 μm, more preferably in the range of 0.5 μm to 5.0 μm, and even more preferably in the range of 0.8 μm to 4.0 μm.

[0075] The average length RSm of the roughness curve element is preferably in the range of 50 μm to 800 μm, more preferably in the range of 80 μm to 600 μm, and even more preferably in the range of 100 μm to 500 μm.

[0076] The upper surface of the surface protective layer 4 can also be sinusoidal in shape in a cross-section parallel to the thickness direction and the arrangement direction of the ridges 4B. Here, as... Figure 4As shown, "sine wave shape" refers to the shape of a line that can be represented by a sine wave from the lowest position C of the ridge 4B to the highest position D (apex).

[0077] The thickness of the surface protective layer 4 is preferably in the range of 2 μm to 20 μm, more preferably in the range of 2.5 μm to 15 μm, and most preferably in the range of 3 μm to 12 μm. When the thickness of the surface protective layer 4 is small, it is difficult to achieve the above-described surface properties by the method described later while referring to the RSm / Ra ratio, etc. When the thickness of the surface protective layer 4 is increased, the processability of the decorative sheet 1 decreases, and it is prone to whitening during bending processing.

[0078] Here, the thickness of the surface protective layer 4 is the thickness of a layer with an apparent area and volume equal to that of the surface protective layer 4 and a flat surface. The thickness of the surface protective layer 4 is determined, for example, by the following method: First, a cross-section parallel to the thickness direction of the surface protective layer 4 and perpendicular to the length direction of the ridge portion 4B is photographed. Next, the dimensions of the surface protective layer 4 in the width direction of the ridge portion 4B and the area of ​​the cross-section of the surface protective layer 4 are determined based on this cross-sectional image. The thickness of the surface protective layer 4 is obtained by dividing this area by the aforementioned dimensions. It should be noted that, in the case where the coating liquid used for the surface protective layer, as described later, is solvent-free, the thickness of the coating film formed by this coating liquid is equal to the thickness of the surface protective layer 4.

[0079] Furthermore, the thickness of the surface protective layer 4 is preferably set such that the ratio of the thickness (or height) of the ridge portion 4B to the thickness of the core portion 4A (thickness of the ridge portion 4B / thickness of the core portion 4A) is in the range of 0.01 to 2.0, and more preferably in the range of 0.1 to 1.0.

[0080] The surface protective layer 4 contains a resin-cured product. As described later, the surface protective layer 4 may also contain particles. When the mass of the surface protective layer 4 is set to 100 parts by mass, the mass of the resin-cured product contained in the surface protective layer 4 is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 80 parts by mass or more.

[0081] The surface protective layer 4 contains a cured product of the second ionizing radiation-curable resin as a resin curing product. According to one example, the surface protective layer 4 contains only a cured product of the second ionizing radiation-curable resin as a resin curing product other than the particles. According to other examples, the surface protective layer 4 contains only a cured product of the second ionizing radiation-curable resin as a resin curing product. As described above, the ionizing radiation is a beam of charged particles such as an electron beam. The second ionizing radiation-curable resin is cured by irradiation with ionizing radiation. Alternatively, the second ionizing radiation-curable resin can also be cured by irradiation with ultraviolet light. The second ionizing radiation-curable resin used here is cured by irradiation with light of wavelength less than 200 nm, which has a high absorption coefficient.

[0082] As a second ionizing radiation curable resin, various known resins such as monomers or commercially available oligomers can be used, for example, (meth)acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, or epoxy resins. The second ionizing radiation curable resin can be either a water-based resin or a non-water-based (organic solvent-based) resin. The second ionizing radiation curable resin can also be solvent-free.

[0083] The main component of the second ionizing radiation curable resin is preferably acrylate. Here, "main component" means that it contains 60 parts by mass or more, more preferably 70 parts by mass or more, and most preferably 80 parts by mass or more, relative to 100 parts by mass of the constituent resin.

[0084] The acrylate is preferably a acrylate with two or more functional groups, more preferably a acrylate with three or more functional groups. In order to obtain a surface protective layer 4 with excellent scratch resistance, the acrylate is preferably three or more functional groups. There is no upper limit to the number of functional groups of the acrylate, and according to one example, it is six functional groups or less.

[0085] The acrylate preferably contains a repeating structure. This repeating structure is, for example, any one of an ethylene oxide (EO) structure, a propylene oxide (PO) structure, and an ε-caprolactone (CL) structure. The repeating structure is preferably ethylene oxide or propylene oxide. In the acrylate, the repeating structure may be located between an acryloyl group and a hydroxymethyl group in the ring-opening state.

[0086] The repetition number of the repeating structure is preferably 3 or more. When using an acrylate with a high repetition number, the cured film is prone to expand inward during the second irradiation step described later, thus easily creating wrinkles on the coating surface corresponding to the ridge 4B. However, as the repetition number increases, the crosslinking density decreases, and the scratch resistance of the surface protective layer 4 decreases. In addition, if the repeating unit is hydrophilic, when the repetition number is too high, water can easily penetrate into the surface protective layer 4 when water adheres to it. Therefore, the repetition number is preferably 30 or less, more preferably 20 or less.

[0087] The number of repetitions of the above repeating structure can be analyzed using MALDI-TOF-MS. Ionizing radiation-cured resins sometimes exhibit molecular weight distributions. In the case of molecular weight distributions, the number of repetitions is set as the number of repetitions corresponding to the molecular weight with the strongest peak in the MALDI-TOF-MS mass spectrum.

[0088] The second ionizing radiation curable resin can be a single acrylate or a mixture of two or more acrylates. For example, the second ionizing radiation curable resin can be a mixture of acrylates containing repeating structures and acrylates not containing repeating structures. In this case, the RSm / Ra ratio described above can be easily adjusted. The ratio M2 / M1 of the mass of the acrylate not containing repeating structures to the mass of the acrylate containing repeating structures is preferably, for example, in the range of 2.0 or less.

[0089] The second type of ionizing radiation-curable resin may also contain methacrylates if it contains acrylates.

[0090] In addition to the resin curing product, the surface protective layer 4 may also contain particles.

[0091] The particles contained in the surface protective layer 4 can be, for example, particles made of organic materials such as polyethylene (PE) wax, polypropylene (PP) wax, and resin beads; or particles made of inorganic materials such as silicon dioxide, glass, alumina, titanium dioxide, zirconium oxide, calcium carbonate, and barium sulfate.

[0092] The average particle size (D50) is preferably 10 μm or less, more preferably in the range of 1 μm to 8 μm, even more preferably in the range of 2 μm to 7 μm, and most preferably in the range of 3 μm to 6 μm. When the average particle size (D50) is increased, the particles may easily detach from the surface protective layer 4, making it difficult to achieve high damage resistance. With smaller particles, the effect of uniformly generating wrinkles becomes less pronounced.

[0093] Here, "average particle size" or "average particle size (D50)" refers to the median particle size (D50) measured by a laser diffraction / scattering particle size distribution measuring device. It should be noted that if the coating liquid used for the surface protective layer contains particles, the surface protective layer 4 obtained from that coating liquid also contains particles. The average particle size of the particles contained in the surface protective layer 4 can be obtained by observing its cross-section, measuring the particle size of multiple particles, and averaging the results. The value obtained in this way is substantially the same as the median particle size (D50) measured by the laser diffraction / scattering particle size distribution measuring device. Therefore, the aforementioned range of average particle size can also be read as the range of the average particle size of the particles contained in the surface protective layer 4.

[0094] Relative to 100 parts by mass of the cured resin product, the amount of particles in the surface protective layer 4 is preferably in the range of 0.5 parts by mass to 20 parts by mass, more preferably in the range of 0.5 parts by mass to 10 parts by mass, further preferably in the range of 2 parts by mass to 8 parts by mass, and most preferably in the range of 2 parts by mass to 6 parts by mass.

[0095] When the amount of particles added is within the above range, the effect of uniform wrinkling is particularly significant. When too many particles are added, the particles may easily detach from the surface protective layer 4, making it difficult to achieve high scratch resistance.

[0096] The combined thickness of the pigment-containing layer 3 and the surface protective layer 4 is preferably in the range of 3 μm to 40 μm, more preferably in the range of 4.5 μm to 30 μm. When the combined thickness of these layers is within the above range, high water resistance can be achieved.

[0097] The thickness of the decorative sheet 1 is preferably in the range of 30 μm to 160 μm, more preferably in the range of 50 μm to 130 μm. When the thickness of the decorative sheet 1 is within the above range, it is easy to bend, thus achieving high processability.

[0098] <2> Manufacturing method of decorative sheet

[0099] Decorative piece 1 is manufactured, for example, by the following method.

[0100] First, a first coating containing pigment and a first ionizing radiation-curable resin is formed on one surface of the paper-containing base layer 2. Here, the first coating is formed in such a way that it covers the entire upper surface of the base layer 2.

[0101] According to one example, the first coating film consists only of a mixture of pigment and a first ionizing radiation-curable resin. According to other examples, the first coating film consists only of a mixture of pigment, a first ionizing radiation-curable resin, and additives dissolved therein.

[0102] The first coating is formed by applying a pigment-containing coating liquid to the base material layer 2. The first coating can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, inkjet printing, etc.; or by various coating methods such as roller coating, doctor blade coating, micro-gravure coating, mold coating, etc.

[0103] The pigment-containing coating liquid contains the aforementioned pigment and a first ionizing radiation-curable resin. The pigment-containing coating liquid may also contain other components, such as thermosetting resins, solvents, and one or more additives for improving the functionality of the final product, such as antibacterial agents and antifungal agents. The pigment-containing coating liquid may also contain other additives such as ultraviolet absorbers and light stabilizers. Examples of ultraviolet absorbers include benzotriazole, benzoate, benzophenone, and triazine compounds. Examples of light stabilizers include hindered amine compounds. When the pigment-containing coating liquid contains a solvent, the first coating film is obtained by drying the coating film formed by coating with the pigment-containing coating liquid.

[0104] Next, the first irradiation step is performed. In the first irradiation step, the first coating is irradiated with a first radiation to cure the first coating. The first irradiation step can be performed in a manner that completely cures the first coating or in a manner that partially cures the first coating.

[0105] The first radiation is, for example, ionizing radiation. As mentioned above, ionizing radiation is a beam of charged particles such as an electron beam. The first radiation can also be ultraviolet light from which the first ionizing radiation-cured resin exhibits a small absorption coefficient. The wavelength of the ultraviolet light irradiating the first coating is preferably greater than 200 nm, more preferably in the range of 230 nm to 450 nm, and even more preferably in the range of 250 nm to 400 nm.

[0106] When the first coating is irradiated with ionizing radiation or the aforementioned ultraviolet light, it can be cured substantially uniformly over its entire thickness. Therefore, unlike the second coating described later, the cured first coating does not have an uneven surface.

[0107] It should be noted that, according to one example, the minimum cumulative light intensity required for the first coating to fully cure is 10 mJ / cm². 2 Above 1000mJ / cm 2 Within the following range. Additionally, according to one example, the minimum absorbed dose required for complete curing of the first coating is in the range of 3 kGy to 200 kGy.

[0108] When the first coating contains a thermosetting resin, the first coating may be heated after the first irradiation step to induce a crosslinking reaction of the thermosetting resin. This heating is preferably performed at a temperature between 80°C and 200°C, and more preferably at a temperature between 100°C and 160°C. It should be noted that even when the first coating contains a thermosetting resin, the first coating may not be heated immediately after the first irradiation step.

[0109] The first irradiation step can also be omitted. For example, if the first coating loses its fluidity due to drying or heating, the first irradiation step can be omitted.

[0110] Next, a second coating film, consisting of a surface protective coating liquid, is formed on the cured first coating film. Here, the second coating film is formed in such a way that it covers the entire upper surface of the first coating film.

[0111] The second coating can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, inkjet printing, etc.; or by various coating methods such as roller coating, doctor blade coating, micro-gravure coating, mold coating, etc.

[0112] The coating liquid for the surface protective layer contains the aforementioned second ionizing radiation-curing resin. As described above, according to one example, the second ionizing radiation-curing resin is an acrylate. Additionally, according to other examples, the second ionizing radiation-curing resin is a mixture of acrylate and methacrylate.

[0113] The coating liquid for the surface protective layer may also contain other components, such as the aforementioned particles, solvents, and one or more additives for improving the functionality of the final product, such as antibacterial agents and antifungal agents. The coating liquid for the surface protective layer may also contain other additives such as ultraviolet absorbers and light stabilizers. Examples of ultraviolet absorbers include benzotriazole series, benzoate series, benzophenone series, and triazine series. Examples of light stabilizers include hindered amine series.

[0114] Next, the second coating is irradiated with ionizing radiation or ultraviolet light to completely cure it. For example, the second irradiation step and the third irradiation step described below are performed sequentially.

[0115] In the second irradiation process, the second coating is irradiated with a second type of radiation. The second type of radiation is light with a wavelength of less than 200 nm.

[0116] The second ionizing radiation-curing resin contained in the coating liquid of the surface protective layer has a high absorption coefficient for the second radiation. Therefore, the second radiation incident on the second coating film can only reach a position tens to hundreds of nm away from its outermost surface. Therefore, in the second irradiation process, a cross-linking reaction occurs in the surface area of ​​the second coating film to form an extremely thin cured film, while in other areas, no cross-linking reaction occurs and it remains uncured.

[0117] The second coating after the second irradiation process has wrinkles on its surface corresponding to the ridge 4B. The inventors believe that the wrinkles are generated on the coating surface by the second irradiation process for the following reasons.

[0118] As described above, the second radiation can only reach locations tens to hundreds of nm away from the outermost surface of the second coating. That is, the cross-linking reaction of the second ionizing radiation-cured resin occurs only on the surface of the second coating; regions farther from the outermost surface than tens to hundreds of nm remain uncured, containing highly fluid molecules. These highly fluid molecules cause the cured film to swell, increasing its volume. Due to the in-plane compressive stress generated by this volume increase, the cured film bends, resulting in wrinkles on the surface of the second coating.

[0119] The second type of radiation can be extracted from excimer VUV (Vacuum Ultra Violet) light. Excimer VUV light can be generated by lamps using rare gases or rare gas halides. When high-energy electrons are applied from the outside to a lamp enclosed in a rare gas or rare gas halide gas, a large amount of discharge plasma (dielectric barrier discharge) is generated. Through this plasma discharge, the atoms of the discharge gas (rare gas) are excited and momentarily enter the excimer state. When returning from this excimer state to the ground state, light in the wavelength region specific to that excimer is emitted.

[0120] The gas used for excimer lamps only needs to emit light below 200 nm, and can be any gas previously used. As the gas, rare gases such as Xe, Ar, and Kr, as well as mixtures of rare gases and halogen gases such as ArBr and ArF, can be used. The wavelength (center wavelength) of the excimer lamp varies depending on the gas, 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).

[0121] Considering the difference between the photon energy, wavelength, and binding energy of organic matter, a xenon lamp emitting excimer light with a center wavelength of 172 nm is preferred as the light source. Furthermore, considering the cost of equipment maintenance and the availability of materials, a xenon lamp is also preferred as the light source.

[0122] The second irradiation step is carried out in an atmosphere with low oxygen concentration. Oxygen has a high absorption coefficient for light below 200 nm. Therefore, the second irradiation step is preferably carried out, for example, in a nitrogen atmosphere. The oxygen concentration in the gas phase of the second irradiation step, i.e., the residual oxygen concentration in the reaction atmosphere, is preferably set to 2000 ppm or less, more preferably 1000 ppm or less.

[0123] Furthermore, oxygen in the atmosphere inhibits free radical polymerization. Therefore, the residual oxygen concentration in the reaction atmosphere affects the formation of wrinkles on the surface of the second coating. Consequently, the surface properties of the surface protective layer 4 may also change when the residual oxygen concentration in the reaction atmosphere changes.

[0124] The cumulative intensity of the second radiation is preferably set at 0.5 mJ / cm². 2 Above 200mJ / cm 2 Within the following range, more preferably at 1 mJ / cm 2 Above 100mJ / cm 2 Within the following range, it is further preferred to be set at 3mJ / cm 2 Above 50mJ / cm 2 Within the following range, the optimal setting is 5 mJ / cm. 2 Above 30mJ / cm 2 Within the following range: When the cumulative light intensity decreases, the in-plane expansion of the cured film decreases. When the cumulative light intensity increases, the surface condition of the second coating deteriorates.

[0125] In the third irradiation step, the second coating is irradiated with a third type of radiation. The third type of radiation is either ionizing radiation or ultraviolet light with a wavelength longer than the light irradiated in the second irradiation step. The third type of radiation can be derived from the first type of radiation mentioned above.

[0126] In the third irradiation step, a crosslinking reaction is carried out over the entire thickness of the second coating.

[0127] The cumulative intensity of the third radiation is preferably set at 10 mJ / cm². 2 Above 500mJ / cm 2 Within the following range, more preferably at 50 mJ / cm 2 Above 400mJ / cm 2 Within the following range, it is further preferred to be set at 100 mJ / cm 2 Above 300mJ / cm 2 Within the following range.

[0128] The third radiation exposure is preferably carried out in a manner with an absorbed dose of 5 kGy to 200 kGy, more preferably in a manner with an absorbed dose of 10 kGy to 150 kGy, and even more preferably in a manner with an absorbed dose of 15 kGy to 100 kGy.

[0129] In the third irradiation step, if a layer with sufficient intensity cannot be obtained by irradiation with only a single type of radiation, the type of the third radiation can be changed simultaneously. For example, irradiation with ionizing radiation can be performed first, followed by irradiation with ultraviolet light with a wavelength longer than that irradiated in the second irradiation step. Alternatively, irradiation with ultraviolet light with a wavelength longer than that irradiated in the second irradiation step can be performed first, followed by irradiation with ionizing radiation. Alternatively, irradiation with ultraviolet light with a wavelength longer than that irradiated in the second irradiation step can be performed first, followed by irradiation with ultraviolet light with an even longer wavelength.

[0130] As described above, decorative piece 1 is obtained. It should be noted that in decorative piece 1 obtained by the above method, there is no interface between the core portion 4A and the ridge portion 4B; they are integrally formed.

[0131] <3> Effect

[0132] The decorative sheet 1 described above has the property of inhibiting stains or marks caused by water absorption, i.e., water resistance. This will be explained below.

[0133] As described above, the base material layer 2 contains paper. Therefore, without omitting the pigment-containing layer 3, when water adheres to the surface protective layer 4, the water is absorbed by the paper contained in the base material layer 2. This absorbent portion can be considered a stain. Furthermore, in the absorbent portion, due to paper shrinkage during the drying process, traces of water absorption can be seen even after drying.

[0134] The surface protective layer 4 can impart a certain degree of water resistance to the decorative piece 1. However, as mentioned above, the surface protective layer 4 has an uneven surface structure, resulting in uneven thickness. Therefore, in order to achieve high water resistance solely through this surface protective layer 4, its minimum thickness needs to be significantly increased. However, since the thickness of the second coating may affect the surface properties of the surface protective layer 4, the thickness of the surface protective layer 4 cannot be determined solely based on water resistance.

[0135] In contrast, the decorative sheet 1 described above includes a pigment-containing layer 3 containing a cured product of a first ionizing radiation-curable resin. Compared to cured products of resins such as thermosetting resins, the first ionizing radiation-curable resin has a high crosslinking density. Therefore, even if water adhering to the surface protective layer 4 reaches the pigment-containing layer 3, the water will not pass through the pigment-containing layer 3. Thus, the decorative sheet 1 described above can achieve high water resistance.

[0136] Furthermore, the decorative piece 1 described above has an uneven structure on the surface of its protective layer. The ratio of the average length RSm of the roughness curve element of this uneven structure to the arithmetic mean roughness Ra, RSm / Ra, is preferably within the aforementioned range. Such an uneven structure enables the achievement of low gloss.

[0137] Furthermore, the decorative piece 1 has a textured structure on the surface of its protective layer, comprising multiple ridges protruding in a ridge-like manner. This textured structure enables high scratch resistance.

[0138] Example

[0139] Hereinafter, examples of the present invention will be described. It should be noted that the “particle size” described below refers to the “average particle size (D50)” mentioned above.

[0140] <Example 1>

[0141] The reference was created using the following method. Figures 1 to 4 Decorative piece 1 as described.

[0142] First, prepare a unit area mass of 50g / m². 2 Impregnated paper (GFR-506: manufactured by Xingren Co., Ltd.) is used as the raw material layer 2.

[0143] Next, a pigment-containing layer coating liquid having the following composition is applied to the original material layer 2. The pigment-containing layer coating liquid is applied in such a way that the thickness of the pigment-containing layer 3 is 5 μm.

[0144] (The pigment contains a coating liquid)

[0145] • First ionizing radiation-cured resin

[0146] Type: Water-based UV-curable resin

[0147] Product Name: Ziguang (Registered Trademark) UV-W300 (Manufactured by Mitsubishi Chemical Corporation)

[0148] ·pigment

[0149] Type: Titanium oxide

[0150] Average particle size: 230nm

[0151] Mixture: 15 parts by weight

[0152] Then, the first irradiation step is performed. Specifically, the first coating film, which is composed of a pigment-containing layer coating liquid, is irradiated with an electron beam as ionizing radiation in such a way that the absorbed dose of the first coating film is 3 kGy. As a result, the first coating film is cured.

[0153] Next, a surface protective layer coating liquid having the following composition is printed onto the first coating film. The surface protective layer coating liquid is printed in such a way that the thickness of the surface protective layer 4 is 5 μm.

[0154] (Surface protective coating liquid)

[0155] • Second type of ionizing radiation-cured resin

[0156] Type: Trimethylolpropane EO-modified triacrylate (EO6 molar addition)

[0157] Product Name: Miramer M3160 (Made by Miwon)

[0158] Mixture: 100 parts by weight

[0159] ·particle

[0160] Product Name: SYLYSIA 250N (Manufactured by Fuji Silysia Chemical Ltd.)

[0161] Particle size: 5μm

[0162] Mixture: 0.5 parts by weight

[0163] Next, the second irradiation process is carried out. Specifically, an Xe excimer lamp is used in a nitrogen atmosphere with atmospheric pressure and an oxygen concentration of 500 ppm to achieve a cumulative light intensity of 50 mJ / cm². 2 The surface of the second coating film, which is composed of a surface protective layer and a coating liquid, is irradiated with ultraviolet light of a wavelength of 172 nm. As a result, wrinkles are generated on the surface of the second coating film.

[0164] Next, the third irradiation process is carried out. Specifically, the second coating is irradiated with 100 kGy of ionizing radiation to completely cure the second coating, thereby forming the surface protective layer 4.

[0165] Decorative piece 1 was obtained through the above process.

[0166] <Example 2>

[0167] The following resin was used as the second ionizing radiation curable resin, and the thickness of the surface protective layer 4 was set to 20 μm. Otherwise, a reference was manufactured using the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0168] • Second type of ionizing radiation-cured resin

[0169] Type: Trimethylolpropane EO-modified triacrylate (EO30 molar addition)

[0170] Product Name: NAM-AT30E (Manufactured by Nagase America LLC)

[0171] Mixture: 100 parts by weight

[0172] <Example 3>

[0173] Except that the thickness of the surface protective layer 4 was set to 1 μm, a reference was manufactured using the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0174] <Example 4>

[0175] Except for using the following resin as the second ionizing radiation curing resin, a reference was manufactured by the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0176] • Second type of ionizing radiation-cured resin

[0177] Type: Ethoxylated trimethylolpropane triacrylate

[0178] Product Name: A-TMPT-6PO (Manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0179] Mixture: 100 parts by weight

[0180] <Example 5>

[0181] Except for using the following resin as particles, a reference was manufactured using the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0182] ·particle

[0183] Product Name: SYLYSIA 780 (Manufactured by Fuji Silysia Chemical Ltd.)

[0184] Particle size: 11.3 μm

[0185] Mixture: 5 parts by weight

[0186] <Example 6>

[0187] Except that the thickness of the pigment-containing layer 3 was set to 1.5 μm, a reference was manufactured using the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0188] <Example 7>

[0189] Except that the thickness of the pigment-containing layer 3 was set to 22 μm, a reference was manufactured using the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0190] <Example 8>

[0191] Except for using the following resin as the first ionizing radiation curable resin, a reference was manufactured by the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0192] • First ionizing radiation-cured resin

[0193] Type: Water-based UV-curable resin

[0194] Product Name: UVPUD-7502E (Manufactured by UBE Company)

[0195] <Example 9>

[0196] Except for using a mixture of the following resins as the second ionizing radiation curing resin, a reference was manufactured by the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0197] • Second type of ionizing radiation-cured resin

[0198] (First acrylate)

[0199] Type: Trimethylolpropane EO-modified triacrylate (EO6 molar addition)

[0200] Product Name: Miramer M3160 (Made by Miwon)

[0201] Formula: 60 parts by weight

[0202] (Second acrylate)

[0203] Type: Dipentaerythritol hexaacrylate (DPHA)

[0204] Product Name: ARONIX M-404 (Manufactured by Toa Synthetic Co., Ltd.)

[0205] Formula: 40 parts by weight

[0206] <Example 10>

[0207] Except for using a mixture of the following resins as the second ionizing radiation curing resin, a reference was manufactured by the same method as in Example 1. Figures 1 to 4 Decorative piece 1 as described.

[0208] • Second type of ionizing radiation-cured resin

[0209] (First acrylate)

[0210] Type: Trimethylolpropane EO-modified triacrylate (EO6 molar addition)

[0211] Product Name: Miramer M3160 (Made by Miwon)

[0212] Formula: 40 parts by weight

[0213] (Second acrylate)

[0214] Type: Dipentaerythritol hexaacrylate (DPHA)

[0215] Product Name: ARONIX M-404 (Manufactured by Toa Synthetic Co., Ltd.)

[0216] Formula: 60 parts by weight

[0217] <Comparative Example 1>

[0218] The second irradiation step was omitted, and the particle composition of the surface protective layer in the coating liquid was set to 20 parts by mass. Otherwise, a product similar to the reference was manufactured using the same method as in Example 1. Figures 1 to 4 Similar decorative pieces are described.

[0219] <Comparative Example 2>

[0220] A mixture of the following resins was used as the second ionizing radiation curable resin, and the thickness of the surface protective layer 4 was set to 1 μm. Otherwise, a product similar to the reference was manufactured using the same method as in Example 1. Figures 1 to 4 Similar decorative pieces are described.

[0221] • Second type of ionizing radiation-cured resin

[0222] (First acrylate)

[0223] Type: Trimethylolpropane EO-modified triacrylate (EO6 molar addition)

[0224] Product Name: Miramer M3160 (Made by Miwon)

[0225] Mixture: 20 parts by weight

[0226] (Second acrylate)

[0227] Type: Dipentaerythritol hexaacrylate (DPHA)

[0228] Product Name: ARONIX M-404 (Manufactured by Toa Synthetic Co., Ltd.)

[0229] Mixture: 80 parts by weight

[0230] <Comparative Example 3>

[0231] Except that the following resin was used instead of the first ionizing radiation curable resin, the same method as in Example 1 was used to manufacture a product similar to the reference resin. Figures 1 to 4Similar decorative sheets as described.

[0232] Type: Aqueous acrylic dispersion

[0233] Product name: SETAQUA6411 (manufactured by Daicel-Allnex Ltd.)

[0234] Composition: 100 parts by mass

[0235] <Comparative Example 4>

[0236] Except for using the following resin instead of the first ionizing radiation curable resin, a decorative sheet similar to the reference was manufactured by the same method as in Example 1. Figures 1 to 4 Similar decorative sheets as described.

[0237] Type: Thermosetting polyurethane resin

[0238] Product name: WS-5661 (manufactured by Mitsui Chemicals, Inc.)

[0239] Composition: 100 parts by mass

[0240] <Evaluation>

[0241] The above decorative sheets were evaluated as described below. Note that decorative sheets evaluated as "AAA", "AA", or "A" have no problems in actual use and are therefore considered qualified. [[ID=3३]]

[0242] (1) Thickness of the surface protective layer

[0243] The thickness of the surface protective layer was measured by the same method as above.

[0244] Specifically, the decorative sheet was embedded in a resin such as a cold-curing type epoxy resin or a UV curable resin, and the resin was fully cured. Then, it was cut to expose the cross-section of the decorative sheet, and a measurement surface was obtained by mechanical polishing.

[0245] Next, a cross-section of the surface protective layer was photographed using a scanning electron microscope SIGMA500 manufactured by Carl Zeiss Microscopy GmbH. When taking this photograph, the acceleration voltage was set to 0.5 keV (low acceleration voltage), the imaging mode was set to SE2 mode, and the magnification was set to 2000 times. Note that the measurement sample was not sputtered.

[0246] Next, based on this cross-sectional image, the size of the surface protective layer in the width direction of the ridge portion and the area of the cross-section of the surface protective layer were determined. The thickness of the surface protective layer was calculated by dividing this area by the above size. The thickness obtained in this way is equal to the thickness of the coating film composed of the surface protective layer coating liquid.

[0247] In addition, the thickness of the pigment-containing layer was measured using the same method as described above.

[0248] (2) Gloss

[0249] Regarding gloss, the specular gloss GS (60°) was measured using a Rhopoint IQ-S (manufactured by Rhopoint Instruments). The “60° gloss value” in Tables 1 and 2 below represents the specular gloss GS (60°).

[0250] (3) Damage resistance

[0251] Each decorative panel was adhered to the wood substrate B using a urethane-based adhesive. Then, a steel wool abrasion test was performed as an evaluation of scratch resistance. Specifically, the decorative panel was rubbed back and forth with steel wool 20 times while a load of 100g was applied, and any damage or changes in gloss on the surface of the decorative panel were visually confirmed.

[0252] The evaluation criteria are as follows.

[0253] AAA: No damage or change in gloss was observed on the surface.

[0254] AA: A portion of the surface has experienced minor damage or a change in gloss.

[0255] A: The surface has suffered minor damage or a change in gloss.

[0256] B: The surface has obvious damage or changes in gloss.

[0257] (4) Water resistance

[0258] Use a urethane-based adhesive to glue each decorative piece onto the wood substrate B. Drip water onto the protective coating of each decorative piece, cover it with a dial, and leave it for 24 hours. Then, wipe the water off the protective coating and observe the decorative piece.

[0259] The evaluation criteria are as follows.

[0260] AAA: Absolutely no stains or water marks.

[0261] AA: There are stains or water absorption marks in some areas, but it is difficult to identify them.

[0262] A: There are stains or water absorption marks in some areas, which are relatively easy to identify.

[0263] B: The water absorption marks are clearly visible throughout.

[0264] (5) Bending workability

[0265] The obtained decorative sheets are then subjected to wrapping. The surface of the decorative sheets is examined using an optical microscope to observe whether whitening or cracking occurs at the bent portions, thus evaluating the processability. It should be noted that this wrapping processability is equivalent to so-called bending processability.

[0266] The evaluation criteria are as follows.

[0267] AAA: No whitening or cracking was observed.

[0268] AA: Some areas show slight whitening.

[0269] A: Partial whitening has occurred.

[0270] B: The entire surface is whitened or partially cracked.

[0271] The evaluation results are shown in Tables 1 to 3. It should be noted that in the "Resin Type" column of Tables 1 to 3, "A-1" indicates the use of UV-W300 (manufactured by Mitsubishi Chemical Corporation, a registered trademark), "A-2" indicates the use of UVPUD-7502E (manufactured by UBE Corporation), "B" indicates the use of SETAQUA6411 (manufactured by Daicel-Allnex Ltd.), and "C" indicates the use of WS-5661 (manufactured by Mitsui Chemicals Co., Ltd.).

[0272]

[0273]

[0274]

[0275] As shown in Tables 1 to 3, the decorative sheets involved in Examples 1 to 10 all exhibited sufficient performance in terms of low gloss, scratch resistance, water resistance, and processability. In contrast, the decorative sheet involved in Comparative Example 1 did not perform adequately in terms of scratch resistance. Furthermore, the sheet involved in Comparative Example 2 did not perform adequately in terms of low gloss and bending processability. Additionally, the sheets involved in Comparative Examples 3 and 4 did not perform adequately in terms of water resistance.

[0276] Explanation of symbols

[0277] 1…Decorative piece, 2…Material layer, 3…Pigment-containing layer, 4…Surface protective layer, 4A…Core, 4B…Spine, 11…Decorative material, B…Substrate, C…Position, D…Position.

Claims

1. A decorative piece, comprising: Contains paper-based raw material layers, A pigment-containing layer disposed on the original material layer and containing a cured product and pigment of a first ionizing radiation-curable resin, and a pigment-containing layer thereof. A surface protective layer disposed on the pigment-containing layer The surface protective layer contains a cured product of a second ionizing radiation-curable resin as the resin curing product, and has a concave-convex structure on its surface comprising multiple ridge-shaped portions, each protruding in a ridge-like manner. The ratio of the average length RSm of the roughness curve element of the concave-convex structure to the arithmetic mean roughness Ra, RSm / Ra, is in the range of 10 to 800.

2. The decorative piece according to claim 1, wherein, The first ionizing radiation-curable resin contains acrylate.

3. The decorative piece according to claim 1 or 2, wherein, The thickness of the pigment-containing layer is in the range of 0.5 μm to 20 μm.

4. The decorative piece according to any one of claims 1 to 3, wherein, The thickness of the surface protective layer is in the range of 2 μm to 20 μm.

5. The decorative piece according to any one of claims 1 to 4, wherein, The combined thickness of the pigment-containing layer and the surface protective layer is in the range of 3 μm to 40 μm.

6. The decorative piece according to any one of claims 1 to 5, wherein, When the mass of the first ionizing radiation curable resin is set to 100 parts by mass, the mass of the pigment is 3 to 50 parts by mass.

7. The decorative piece according to any one of claims 1 to 6, wherein, The pigment is titanium dioxide.

8. The decorative sheet according to any one of claims 1 to 7, wherein, The second ionizing radiation-curable resin contains acrylate.

9. The decorative piece according to any one of claims 1 to 8, wherein, The second ionizing radiation-curable resin contains acrylates with two or more functions, including repeating structures.

10. The decorative piece according to claim 9, wherein, The repeating structure is repeated 3 times or more.

11. The decorative sheet according to claim 9 or 10, wherein, The number of repetitions in the repeating structure is 30 or less.

12. The decorative sheet according to any one of claims 1 to 11, wherein, The surface protective layer also contains particles with an average particle size of less than 10 μm.

13. The decorative piece according to claim 12, wherein, When the mass of the second ionizing radiation curable resin is set to 100 parts by mass, the mass of the particles is in the range of 0.5 parts by mass to 20 parts by mass.

14. The decorative sheet according to any one of claims 1 to 13, wherein, The gloss level of the surface protective layer is below 20.

0.

15. A decorative material, comprising: The decorative piece as described in any one of claims 1 to 14, and The substrate for attaching the decorative piece.

16. A method for manufacturing a decorative sheet, comprising: A first coating containing pigment and a first ionizing radiation-curable resin is formed on a paper-containing raw material layer; A second coating film containing a second ionizing radiation-curable resin is formed on the first coating film; and Ionizing radiation or ultraviolet light is irradiated onto the second coating film to completely cure the second coating film.

17. The method for manufacturing a decorative sheet according to claim 16, wherein, The complete curing of the second coating includes: An irradiation process in which the second coating film is irradiated with light of wavelength less than 200 nm; Then, the second coating is irradiated with ionizing radiation or with ultraviolet light with a wavelength longer than that of the light irradiated in the irradiation process.

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