Decorative sheets and decorative panels

Abstract

To provide a decorative sheet that can suppress coating defects during film formation and also has excellent abrasion resistance. [Solution] A decorative sheet comprising a base sheet and at least a protective layer, wherein the protective layer contains a cured product of a cross-linked curable resin and alumina particles, and the alumina particles contain electrofused alumina particles.

Description

[Technical Field]

[0001] This invention relates to decorative sheets and decorative panels. [Background technology]

[0002] Decorative sheets with designs are used to adorn building materials, furniture, home appliances, and other items.

[0003] In decorative sheets used to decorate floors, especially those used for floors where shoes are worn, a protective layer containing alumina particles may be provided on the surface to improve scratch resistance and abrasion resistance.

[0004] For example, Patent Document 1 discloses an embodiment in which a resin curing layer is provided on at least one side of a substrate, and the resin curing layer contains alumina particles. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-82440 [Overview of the project] [Problems that the invention aims to solve]

[0006] For decorative sheets used as flooring in areas with heavy foot traffic, attempts have been made to improve abrasion resistance by increasing the amount of alumina particles added to the protective layer.

[0007] However, when attempting to form such a protective layer, there were problems such as coating defects occurring during film formation due to increased viscosity associated with increasing the amount of alumina particles added.

[0008] Furthermore, as the amount of alumina particles added increased, the compatibility between the coating agent containing the cross-linked curing resin and the alumina particles decreased, causing the alumina particles to detach from the cured coating film, resulting in insufficient abrasion resistance.

[0009] Therefore, the present invention aims to provide a decorative sheet that can suppress coating defects during film formation and also has excellent abrasion resistance. [Means for solving the problem]

[0010] The inventors have discovered that in a decorative sheet having at least a protective layer on a base sheet, using electrofused alumina particles as the alumina particles contained in the protective layer improves the fluidity of the coating agent containing a cross-linked curable resin and suppresses coating defects. Furthermore, they have found that it is possible to suppress the generation of brittle secondary particles of alumina particles and improve compatibility with the coating agent, thereby suppressing the shedding of alumina particles and obtaining a decorative sheet with excellent abrasion resistance, thus completing the present invention.

[0011] In other words, the present invention provides a decorative sheet comprising a base sheet with at least a protective layer, wherein the protective layer contains a cured product of a crosslinked curable resin and alumina particles, and the alumina particles contain electrofused alumina particles.

[0012] In the decorative sheet of the present invention, the protective layer is preferably 30 μm or more and 80 μm or less in thickness. Furthermore, it is preferable that the cured product of the above-mentioned cross-linked curing resin is a cured product of an ionizing radiation curing resin. Furthermore, it is preferable that the electrofused alumina particles have an average particle diameter of 10 μm or more and 60 μm or less. Furthermore, the above-mentioned electrofused alumina particles have a heavy-load bulk density of 1.5 g / cm³. 3 More than 2.3g / cm 3 The following is preferable: Furthermore, it is preferable that the above-mentioned electrofused alumina particles have a porosity of 1.0% to 7.0%. Also, the electrofused alumina particles are preferably spherical. Also, the content of the electrofused alumina particles is preferably 30% by mass or more and 100% by mass or less with respect to the total mass of the alumina particles. Also, for the protective layer, the content of the alumina particles is preferably 30% by mass or more and 100% by mass or less with respect to the cured product of the crosslinking and curing type resin. Also, the protective layer preferably has an uneven shape on the side opposite to the side provided with the base material sheet. Also, it is preferable to provide a pattern layer and a transparent resin layer in this order from the base material sheet side between the base material sheet and the protective layer. Also, a second protective layer is provided on the side opposite to the side of the protective layer provided with the base material sheet, and the second protective layer preferably contains a cured product of a radiation-curable resin. Also, the protective layer preferably contains a biomass-derived component. Moreover, the present invention is also a decorative panel provided with the decorative sheet on a substrate.

Advantages of the Invention

[0013] The present invention provides a decorative sheet that can suppress coating defects during film formation and also has excellent abrasion resistance.

Brief Description of the Drawings

[0014] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating a preferred example of the decorative sheet of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically illustrating another preferred example of the decorative sheet of the present invention.

Modes for Carrying Out the Invention

[0015] <Decorative Sheet> The cosmetic sheet of the present invention includes at least a protective layer on a base sheet, and the protective layer contains a cured product of a crosslinking and curing type resin and alumina particles, and the alumina particles contain fused alumina particles.

[0016] FIG. 1 is a cross-sectional view schematically illustrating an example of the cosmetic sheet of the present invention. As shown in FIG. 1, the cosmetic sheet 10 includes at least a protective layer 4 on a base sheet 1, and the protective layer 4 contains alumina particles 5. Further, between the base sheet 1 and the protective layer 4, a pattern layer 2 and a transparent resin layer 3 are provided in this order from the side of the base sheet 1. Further, in the cosmetic sheet 10, unevenness 6 is provided on the side opposite to the side of the protective layer 4 that includes the base sheet 1.

[0017] FIG. 2 is a cross-sectional view schematically illustrating another preferable example of the cosmetic sheet of the present invention. As shown in FIG. 2, the cosmetic sheet 10 includes at least a protective layer 4 on a base sheet 1, and the protective layer 4 contains alumina particles 5. Further, between the base sheet 1 and the protective layer 4, an adhesion auxiliary layer 8a (also referred to as a pattern auxiliary layer), a pattern layer 2, an adhesive layer 9, a transparent resin layer 3, and an adhesion auxiliary layer 8b (also referred to as a surface adhesion auxiliary layer) are provided in this order from the side of the base sheet 1. Further, an adhesion auxiliary layer 8c (also referred to as a back surface adhesion auxiliary layer) is provided on the side opposite to the side of the base sheet 1 that includes the protective layer 4, and a second protective layer 7 is provided on the side opposite to the side of the protective layer 4 that includes the base sheet 1. Further, in the cosmetic sheet 10, unevenness 6 is provided on the side opposite to the side of the protective layer 4 that includes the base sheet 1 (the side of the second protective layer). Hereinafter, each component of the cosmetic sheet of the present invention will be described in detail.

[0018] (Protective layer) The cosmetic sheet of the present invention includes a protective layer.

[0019] The protective layer contains a cured product of a crosslinking and curing type resin and alumina particles.

[0020] While a thermosetting resin may be used as the crosslinking-curing resin, an ionizing radiation-curing resin is preferred from the viewpoint of providing suitable wear resistance.

[0021] Examples of thermosetting resins include ester-based urethanes and acrylic-based urethanes.

[0022] Examples of ionizing radiation-curable resins include oligomers and / or monomers having radically polymerizable unsaturated groups or cationic polymerizable functional groups in their molecules. Ionizing radiation refers to electromagnetic waves or charged particles with energy capable of polymerizing or crosslinking molecules, and commonly refers to electron beams (EB) or ultraviolet rays (UV). The method for forming the protective layer is not particularly limited, and known methods can be used.

[0023] As oligomers having radically polymerizable unsaturated groups in the molecule, oligomers such as urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, and triazine (meth)acrylate can be preferably used, with urethane (meth)acrylate oligomers being even more preferred. The molecular weight is usually between 250 and 100,000.

[0024] As monomers having radically polymerizable unsaturated groups in the molecule, polyfunctional monomers are preferred, and polyfunctional (meth)acrylates are more preferred. Examples of polyfunctional (meth)acrylates include diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, bisphenol A ethylene oxide modified di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate {pentafunctional (meth)acrylate}, and dipentaerythritol hexa(meth)acrylate {hexafunctional (meth)acrylate}. Monofunctional monomers may also be used as appropriate.

[0025] The ionizing radiation-curable resin preferably contains a urethane acrylate oligomer and a polyfunctional monomer in a mass ratio of urethane acrylate oligomer to polyfunctional monomer in the range of 6 / 4 to 9 / 1.

[0026] When crosslinking an ionizing radiation-curable resin with ultraviolet light, it is preferable to use a photopolymerization initiator. The photopolymerization initiator can be appropriately selected from known photopolymerization initiators, and the amount of photopolymerization initiator added is, for example, 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of ionizing radiation-curable resin.

[0027] The cross-linked curing resin may also contain biomass-derived resin. By including biomass-derived resin, the environmental impact can be reduced. As a biomass-derived resin, urethane (meth)acrylate or the like, which consists of biomass-derived components, can be used. The urethane (meth)acrylate comprising the above biomass-derived components contains at least one biomass-derived component among the polyol, isocyanate compound, and hydroxy(meth)acrylate contained in the urethane (meth)acrylate.

[0028] The cross-linked curable resin preferably has a weight-average molecular weight of 1,000 to 20,000. In this specification, weight-average molecular weight is the average molecular weight measured by GPC analysis and converted to standard polystyrene.

[0029] The cross-linked curing resin preferably has a glass transition temperature (Tg) of -55°C or higher and 250°C or lower. In this specification, the glass transition temperature (Tg) is a value measured using differential thermal analysis (DTA) or differential scanning calorimetry (DSC) in accordance with JIS K 7121:2012.

[0030] The alumina particles contain electrofused alumina particles. The electrofused alumina particles are alumina particles obtained by melting sintered alumina in an electric furnace (at 2000 °C or higher) to form an ingot and then pulverizing it with a ball mill or the like. Note that sintered alumina can be obtained, for example, by pressure-molding aluminum hydroxide with a briquetting machine or the like, and then sintering it at a high temperature close to its melting point (2050 °C) in a rotary kiln after drying.

[0031] From the viewpoint of suitably imparting abrasion resistance, the electrofused alumina particles preferably have an average particle diameter of 10 μm or more and 60 μm or less. In this specification, the "average particle diameter" means the average value (arithmetic mean diameter) of the particle diameters measured for 100 non-aggregated particles randomly selected by observing a cross-section in the thickness direction of the cosmetic sheet with a scanning electron microscope (SEM). When the alumina particles are amorphous, they are calculated using the equivalent diameter of the circumference circle. The average particle diameter of the electrofused alumina particles is more preferably 15 μm or more, and even more preferably 20 μm or more. Also, it is more preferably 55 μm or less, and even more preferably 50 μm or less.

[0032] From the viewpoints of suppressing coating defects and suppressing the dropout of alumina particles, the tapped bulk density of the electrofused alumina particles is preferably 1.5 g / cm 3 or more and 2.3 g / cm 3 or less. In this specification, the "tapped bulk density" means the tapped bulk density measured and calculated in accordance with JIS R 9301-2-3:1999. The tapped bulk density of the electrofused alumina particles is more preferably 1.6 g / cm 3 or more, even more preferably 1.7 g / cm 3 or more, and particularly preferably 1.8 g / cm 3 or more. Also, it is more preferably 2.2 g / cm 3 or less, and even more preferably 2.0 g / cm 3 or less.

[0033] From the viewpoint of suppressing coating defects and preventing the shedding of alumina particles, it is preferable that the porosity of the electrofused alumina particles be between 1.0% and 7.0%. In this specification, "porosity" refers to the porosity measured and calculated in accordance with JIS R 1655:2003. The porosity of the electrofused alumina particles is more preferably 2% or more, even more preferably 3% or more, and even more preferably 6.8% or less.

[0034] Electrofused alumina particles can be spherical, fibrous, plate-like, irregularly shaped, or flaky, but from the viewpoint of providing suitable wear resistance, they are preferably spherical. Note that "spherical" may refer to a perfect sphere, a nearly spherical shape, a spheroid, etc.

[0035] In addition to fused alumina particles, sintered alumina particles and the like may also be included as alumina particles.

[0036] The content of electrofused alumina particles is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass, relative to the total mass of alumina particles.

[0037] From the viewpoint of suppressing coating defects and preventing the shedding of alumina particles, the alumina particle content is preferably 30% by mass or more and 100% by mass or less relative to the cured product of the cross-linked curable resin. It is more preferable that the alumina particle content be 50% by mass or more relative to the cured product of the cross-linked curable resin.

[0038] The protective layer may contain various additives such as dyes and pigments, weathering agents, light stabilizers, fillers, defoamers, matting agents, leveling agents, thixotropy-imparting agents, flame retardants, antibacterial agents, antiviral agents, and anti-allergen agents. The amount of each additive should be appropriately selected according to its respective properties.

[0039] As a method for forming a protective layer, a coating agent containing a cross-linked curable resin, alumina particles, additives as needed, and a known solvent may be applied by a known method and cured by ionizing radiation or the like.

[0040] The protective layer is preferably 30 μm to 80 μm thick. By having the protective layer thickness within the above range, abrasion resistance can be suitably provided. The protective layer is preferably 40 μm or thicker, and preferably 70 μm or less. Furthermore, if the uneven surface described later is formed, the thickness of the protective layer is defined as the length from the area on the protective layer surface where the uneven surface is not formed to the surface on the transparent resin layer side of the protective layer.

[0041] (Base sheet) The decorative sheet of the present invention comprises a base sheet.

[0042] Examples of resins that make up the base sheet include ester resins, olefin resins, urethane resins, acrylic resins, polycarbonate resins, polystyrene resins; vinyl chloride resins, vinyl acetate resins, and vinyl chloride-vinyl acetate copolymer resins. Among these, ester resins and olefin resins are preferred, and polyethylene and polypropylene are more preferred.

[0043] Furthermore, in recent years, the use of biomass-derived resins or recycled resins, which have a low environmental impact, has been explored in many fields. The resin used to form the base sheet of the decorative sheet of the present invention can also contain components of biomass-derived or recycled resins. Specifically, biomass polyolefins, recycled polyolefins, and the like can be used.

[0044] The base sheet may be colored as needed. Furthermore, the surface may be treated with surface treatments such as corona discharge, plasma treatment, or ozone treatment, or a primer may be applied to enhance adhesion with adjacent layers.

[0045] The base sheet may contain various additives as needed, such as colorants, fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, UV absorbers, antioxidants, and light stabilizers. The amount of each additive should be selected appropriately according to its respective properties.

[0046] The base sheet may have surface treatments such as corona discharge treatment, plasma treatment, or ozone treatment applied to its surface, or it may have a primer applied to it, which is a base coat to improve adhesion with adjacent layers.

[0047] The thickness of the base sheet is preferably, for example, 50 μm or more and less than 100 μm, and more preferably 60 μm or more and 80 μm or less.

[0048] There are no particular limitations on the specific method for forming a film (sheeting) on ​​the base sheet. Examples include the T-die method, which involves extruding molten resin using a T-die to laminate the sheet, the calendering method, and the circular die method (inflation method, tubular method). Among these, the T-die method is preferred when it is necessary to improve production efficiency (production speed) or to alleviate internal stress during sheeting. The calendering method is preferred when it is necessary to make the thickness of the base sheet uniform or to reduce foreign matter defects.

[0049] (Picture layer) The decorative sheet of the present invention preferably includes a pattern layer.

[0050] The pattern layer applies a desired pattern (design) to the decorative sheet, and the type of pattern is not limited. Examples include wood grain, stone pattern, sand pattern, tile pattern, brick pattern, fabric pattern, leather texture, geometric figures, letters, symbols, abstract patterns, etc.

[0051] The ink used to form the pattern layer contains a coloring agent component, a resin component, and a liquid component. The ink may also be appropriately mixed with extender pigments, solvents, stabilizers, plasticizers, catalysts, curing agents, etc.

[0052] As coloring agents, for example, inorganic pigments such as carbon black (ink), iron black, titanium white, antimony white, lead yellow, titanium yellow, iron oxide, cadmium red, ultramarine, and cobalt blue; organic pigments or dyes such as quinacridone red, isoindolinone yellow, and phthalocyanine blue; metallic pigments in the form of flaky foil pieces such as aluminum and brass; and pearlescent pigments in the form of flaky foil pieces such as titanium dioxide-coated mica and basic lead carbonate can be used. As for the resin components, there are no particular restrictions, and any of the following can be used, for example, urethane resins, acrylic resins, ester resins, amide resins, butyral resins, styrene resins, nitrocellulose resins, cellulose acetate resins, acrylic-urethane resins, vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-acrylic copolymer resins, chlorinated polypropylene resins, etc., either individually or in combination of two or more. As liquid components, for example, organic solvents such as methyl ethyl ketone, toluene, cyclohexanone, ethyl acetate alcohol, ethanol, methanol, or water can be used.

[0053] The pattern layer can be formed by partially printing an ink containing coloring agents, resin components, and liquid components using a gravure printing method with an intaglio roll. The pattern layer may also be formed by partially printing inks of the same or different compositions in different areas and / or overlapping them in the same area multiple times.

[0054] The thickness of the pattern layer is preferably, for example, 0.1 μm or more and 5 μm or less.

[0055] (Transparent resin layer) The decorative sheet of the present invention preferably comprises a transparent resin layer. Furthermore, the term "transparency" above means that the image layer may be semi-transparent or colored, as long as it is visible.

[0056] As the transparent resin layer, for example, in addition to ester resins and olefin resins, acrylic resins, carbonate resins, urethane resins, styrene resins, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, etc., can be used. From the viewpoint of improving moldability and scratch resistance, ester resins and olefin resins are preferred, and olefin resins such as polypropylene and polyester are more preferred.

[0057] Furthermore, in recent years, the use of biomass-derived resins or recycled resins, which have a low environmental impact, has been explored in many fields. The resin forming the transparent resin layer of the decorative sheet of the present invention can also contain components of biomass-derived or recycled resins. Specifically, biomass polyolefins, recycled polyolefins, etc., can be used.

[0058] The transparent resin layer may further contain various additives as needed. Examples include antioxidants, UV absorbers, light stabilizers, lubricants, nucleating agents, and colorants such as dyes and pigments. The amount of additives should be appropriately selected according to their respective properties.

[0059] The thickness of the transparent resin layer is preferably 40 μm or more and 150 μm or less. By having the thickness of the transparent resin layer within the above range, the scratch resistance of the decorative sheet can be suitably improved.

[0060] The method for laminating the transparent resin layer is not limited to any particular method, and examples include the dry lamination method and the extrusion lamination method, which involves extruding molten resin using a T-die to create the laminate. Furthermore, T-dies and the like that can extrude molten resin can be used as the extrusion mechanism described above.

[0061] The transparent resin layer may be subjected to surface treatments such as saponification, glow discharge treatment, corona discharge treatment, plasma discharge treatment, ultraviolet (UV) treatment, and flame treatment.

[0062] (Second protective layer) In the present invention, it is preferable that the decorative sheet comprises a second protective layer on the side opposite to the side of the protective layer that has the base sheet. By providing a second protective layer, abrasion resistance can be suitably imparted.

[0063] The second protective layer preferably contains a cured product of an ionizing radiation-curable resin. For ionizing radiation-curing resins, you can select any of the options described in the section on protective layers as appropriate.

[0064] The second protective layer may contain a biomass-derived resin. For biomass-derived resins, you can select the appropriate ones as described in the section on protective layers.

[0065] The second protective layer may contain various additives such as dyes and pigments, weathering agents, fillers, defoamers, matting agents, leveling agents, thixotropy-imparting agents, flame retardants, antibacterial agents, antiviral agents, and anti-allergen agents. The amount of each additive should be appropriately selected according to its respective properties.

[0066] As a method for forming the second protective layer, a coating agent containing a cross-linking curable resin, additives as needed, and a known solvent may be applied by a known method and cured by ionizing radiation or the like.

[0067] The second protective layer is preferably 10 μm or more and 40 μm or less in thickness. Furthermore, if the uneven surface described later is formed, the thickness of the second protective layer shall be the length from the area where the uneven surface is not formed on the second protective layer to the protective layer side surface of the second protective layer.

[0068] (adhesive layer) The decorative sheet of the present invention may have an adhesive layer between the pattern layer and the transparent resin layer. The adhesive layer is preferably transparent.

[0069] As adhesives for forming the adhesive layer, for example, urethane-based adhesives such as ester-based urethane and acrylic-based urethane, acrylic adhesives, epoxy adhesives, and rubber-based adhesives can be used.

[0070] The thickness of the adhesive layer is, for example, between 0.1 μm and 30 μm. Furthermore, the method for forming the adhesive layer is not particularly limited, and any known method may be selected as appropriate.

[0071] (adhesion auxiliary layer) The decorative sheet of the present invention may optionally have an adhesive auxiliary layer (pattern auxiliary layer) between the base sheet and the pattern layer, an adhesive auxiliary layer (surface adhesive auxiliary layer) between the transparent resin layer and the protective layer, or an adhesive auxiliary layer (backside adhesive auxiliary layer) on the back surface of the base sheet (the side opposite to the side with the pattern layer). The adhesion support layer functions as a primer layer or an easy-adhesion layer.

[0072] The adhesive auxiliary layer can be formed using, for example, ester resins, urethane resins, acrylic resins, polycarbonate resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral resins, nitrocellulose resins, etc., and one or more of these resins can be used.

[0073] From the viewpoint of effectively suppressing poor adhesion between layers, the adhesive auxiliary layer is preferably 0.1 μm or more and 30 μm or less in thickness. Furthermore, the method for forming the adhesive auxiliary layer is not particularly limited, and any known method may be selected as appropriate.

[0074] The adhesive layer and adhesive support layer may contain additives as needed. Examples of the additives mentioned above include lubricants such as silicone resins, waxes, and fluororesins; colorants such as dyes and pigments; antioxidants, UV absorbers, light stabilizers, radical scavengers, flame retardants, deodorizers, antibacterial agents, antiviral agents, anti-allergen agents, and antifungal agents. The amount of each additive should be appropriately selected according to its respective properties.

[0075] (uneven shape) From the viewpoint of suitably providing aesthetic appeal, the decorative sheet of the present invention has an uneven shape on the side with the protective layer.

[0076] The uneven surface may extend to the transparent resin layer or the adhesive auxiliary layer (adhesive auxiliary layers 8a, 8b, etc. in Figure 2), or it may be a flat shape (a fine uneven surface).

[0077] Preferably, the maximum height Rz of the uneven surface is, for example, 10 μm or more and 60 μm or less. By having the maximum height Rz of the uneven surface within the above range, it is possible to suitably impart excellent design qualities that allow for a sense of three-dimensionality not only visually but also tactilely (by touch). Note that "maximum height Rz" refers to the maximum height Rz specified in JIS B 0601 (2001).

[0078] The method for forming the uneven shape is not particularly limited and includes, for example, heat embossing and methods for transferring the uneven shape using a shaping sheet. Examples of heat-induced embossing include embossing using a well-known sheet-fed or rotary embossing machine. Examples of embossed patterns include sand texture, hairline finish, pearlescent finish, wood grain groove, stone surface texture, fabric surface texture, and fine groove.

[0079] (others) The decorative sheet of the present invention may optionally have a backer layer on the side opposite to the pattern layer of the base sheet. The presence of a backer layer allows for more favorable impartment of impact resistance.

[0080] The backer layer can be produced by molding a resin composition into a sheet (film) using methods such as calendering, inflation, or T-die extrusion.

[0081] The resin used to form the backer layer is preferably a thermoplastic resin, such as polypropylene (PP), polyethylene (PE), ethylene-propylene copolymer, acrylic, polyurethane, polyvinyl chloride, polymethylene, polymethylpentene, polyethylene terephthalate (PET), polybutylene terephthalate, polycarbonate, polyarylate, polyethylene naphthalate-isophthalate copolymer, polyimide, polystyrene, polyamide, ABS, etc.

[0082] The thickness of the backer layer is preferably, for example, 100 μm or more and 400 μm or less.

[0083] <Manufacturing method for decorative sheets> A method for manufacturing the decorative sheet of the present invention involves applying a coating agent that forms a protective layer onto a base sheet and curing it to form the protective layer. Furthermore, it is preferable to provide a pattern layer and a transparent resin layer between the base sheet and the protective layer, and to provide a second protective layer on the side of the protective layer opposite to the side with the base sheet. Adhesion aid layers and adhesive layers may be provided between each layer as needed. The methods for forming these layers can be those described in the description of each layer.

[0084] In the method for manufacturing the decorative sheet of the present invention, the order in which each layer is formed is not particularly limited. For example, an adhesive auxiliary layer (pattern auxiliary layer), a pattern layer, an adhesive layer, a transparent resin layer, an adhesive auxiliary layer (surface adhesive auxiliary layer), and a protective layer may be formed on one side of the base sheet in this order. Furthermore, the processes for forming each layer do not need to proceed continuously; other processes or treatments may be performed between these processes.

[0085] <Decorative panel> The decorative panel of the present invention comprises a decorative sheet of the present invention on a substrate.

[0086] Examples of substrates include wood-based boards, gypsum-based boards, cement boards, ceramic boards, metal boards, resin boards, and fiber-reinforced plastic boards. As for the method of laminating the substrates, for example, the substrates can be laminated on the side opposite to the side of the base sheet that has a protective layer, with the aforementioned adhesive layer in between.

[0087] This specification discloses the following:

[0088] (1) The present disclosure is a decorative sheet comprising at least a protective layer on a base sheet, wherein the protective layer contains a cured product of a crosslinked curable resin and alumina particles, and the alumina particles contain electrofused alumina particles. Disclosure (2) is a decorative sheet according to Disclosure (1), wherein the protective layer has a thickness of 30 μm or more and 80 μm or less. Disclosure (3) is a decorative sheet as described in Disclosure (1) or (2), wherein the cured product of the crosslinked curable resin is a cured product of an ionizing radiation curable resin. Disclosure (4) is a decorative sheet according to any of Disclosures (1) to (3), wherein the electrofused alumina particles have an average particle diameter of 10 μm or more and 60 μm or less. This disclosure (5) states that the electrofused alumina particles have a heavy bulk density of 1.5 g / cm³. 3 More than 2.3g / cm 3 The decorative sheet is one of the following items (1) to (4) of this disclosure. Disclosure (6) is a decorative sheet according to any of Disclosures (1) to (5), wherein the electrofused alumina particles have a porosity of 1.0% or more and 7.0% or less. Disclosure (7) is a decorative sheet according to any of Disclosures (1) to (6), wherein the electrofused alumina particles are spherical. Disclosure (8) is a decorative sheet according to any one of Disclosures (1) to (7), wherein the content of the electrofused alumina particles is 30% by mass or more and 100% by mass or less relative to the total mass of the alumina particles. Disclosure (9) is a decorative sheet according to any one of Disclosures (1) to (8), wherein the protective layer is a decorative sheet according to any one of Disclosures (1) to (8), wherein the content of the alumina particles is 30% by mass or more and 100% by mass or less relative to the cured product of the crosslinked curable resin. Disclosure (10) is a decorative sheet according to any one of Disclosures (1) to (9) wherein the protective layer has an uneven shape on the side opposite to the side having the base sheet. The present disclosure (11) is a decorative sheet according to any one of the present disclosures (1) to (10), comprising, between the base sheet and the protective layer, a pattern layer and a transparent resin layer in order from the base sheet side. The present disclosure (12) is a decorative sheet according to any one of the present disclosures (1) to (11), wherein the protective layer comprises a second protective layer on the side opposite to the side of the protective layer that has the base sheet, and the second protective layer contains a cured product of an ionizing radiation-curable resin. Disclosure (13) states that the protective layer is a decorative sheet according to any of Disclosures (1) to (12) and contains biomass-derived components. The present disclosure (14) is a decorative panel comprising a decorative sheet described in any of the present disclosures (1) to (13) on a substrate. [Examples]

[0089] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0090] (Example 1) A colored polypropylene sheet with a thickness of 60 μm was prepared as the base material. An adhesive auxiliary layer (backside adhesive auxiliary layer) mainly composed of urethane resin was formed on one side of the base sheet using a gravure printing method with an intaglio roll, so as to cover the entire surface. An adhesive auxiliary layer (pattern auxiliary layer) mainly composed of ester-based polyurethane resin was formed on the other side of the base sheet by solid printing of an ink containing an organic solvent using a gravure printing method with an intaglio roll. Furthermore, a pattern layer mainly composed of acrylic-urethane resin was formed on the side opposite to the side adjacent to the base sheet of the adhesive auxiliary layer by solid printing of an ink containing an organic solvent using a gravure printing method with an intaglio roll. An ester-based polyurethane was applied to the side of the base sheet opposite the patterned layer to form a 10 μm thick adhesive layer, and a 100 μm thick transparent resin layer was formed on the adhesive layer by dry lamination. Furthermore, an adhesive auxiliary layer (surface adhesive auxiliary layer) made of acrylic-urethane copolymer resin with a thickness of 2 μm was formed on the side of the transparent resin layer opposite to the adhesive layer. A coating agent (urethane acrylate-based ionizing radiation-curable resin composition) containing fused alumina particles with a viscosity of 760 mPa·s as measured by an E-type rotational viscometer was applied to the adhesive auxiliary layer using reverse coating. The coating agent was then cured by irradiation with ionizing radiation to form a protective layer with a thickness of 50 μm, thereby manufacturing a decorative sheet.

[0091] The composition of the coating agent used to form the protective layer is as follows: (Coating agent) Bifunctional urethane acrylate oligomer A (polyol component is polyester diol, Tg: 25℃, weight-average molecular weight: 1500) Hexafunctional aliphatic urethane acrylate oligomer B (Tg: 200℃ or higher, weight-average molecular weight: 1500, manufactured by Kyoeisha Chemical Co., Ltd., UA306H) Blending ratio (mass ratio): Bifunctional urethane acrylate oligomer A : Hexafunctional aliphatic urethane acrylate oligomer B = 80 : 20 Content of ionizing radiation-curable resin (total of bifunctional urethane acrylate oligomer A and hexafunctional aliphatic urethane acrylate oligomer B): 100 parts by mass Solvent (ethyl acetate): 100 parts by mass Matting agent (average particle size 11 μm): 8 parts by mass The alumina particles were as described in Table 1.

[0092] (Examples 2-3, 5, 9) The decorative sheet was manufactured in the same manner as in Example 1, except that the alumina particles were modified as shown in Table 1. The average particle size, bulk density, and porosity listed in Table 1 were measured and calculated using the method described herein. Furthermore, in Table 1, "Addition Amount" refers to the content relative to the cured product of the ionizing radiation-curable resin, and in "Type," "Fused" refers to "Fused Alumina Particles," while "Sintered" refers to "Sintered Alumina Particles." Furthermore, in the section on "Types of Cross-Cross-Curing Resins," "EB" refers to ionizing radiation-curing resins, and "UV" refers to ultraviolet-curing resins.

[0093] (Example 4) A decorative sheet was manufactured in the same manner as in Example 1, except that the coating agent was changed to one with the following composition. (Coating agent) Ultraviolet curable resin: 90 parts by mass Product name: UA-33H (manufactured by Shin Nakamura Chemical Industry Co., Ltd.) Properties: Molecular weight 1400, number of functional groups 9 Photopolymerization initiator: 8 parts by mass. Product name: Irgacure 184 (manufactured by BASF). UV absorber A: 2 parts by mass, Product name: Tinuvin 326 (manufactured by BASF) UV absorber B: 2 parts by mass, Product name: Tinuvin P (manufactured by BASF) Light stabilizer: 2.0 parts by mass. Product name: Sanol LS765 (manufactured by BASF). Solvent: 60 parts by mass Product name: Ethyl acetate The alumina particles were as described in Table 1.

[0094] (Example 6) The decorative sheet was manufactured in the same manner as in Example 2, except that the coating agent was changed to one with the following composition. (Coating agent) Glycerin diacrylate A derived from biomass (molecular weight: 348, manufactured by Toagosei Co., Ltd., product name "Arronix M-930") Hexafunctional aliphatic urethane acrylate oligomer B (Tg: 200℃ or higher, molecular weight 1500, manufactured by Kyoeisha Chemical Co., Ltd., product name "UA306H") Mixing ratio (mass ratio): Biomass-derived glycerin diacrylate A: Hexafunctional aliphatic urethane acrylate oligomer B = 80:20 Solvent (ethyl acetate): 100 parts by mass Matting agent (average particle size 11 μm): 8 parts by mass The alumina particles were as described in Table 1. In Table 1, "BO" in the "Types of Cross-linked Curing Resins" column refers to biomass-derived resins.

[0095] (Examples 7 and 8) The decorative sheet was manufactured in the same manner as in Example 3, except that the thickness of the protective layer was changed as shown in Table 1.

[0096] (Comparative Examples 1-2) A decorative sheet was manufactured in the same manner as in Example 1, except that the sintered alumina particles listed in Table 1 were used.

[0097] (Comparative Example 3) The decorative sheet was manufactured in the same manner as in Comparative Example 2, except that the sintered alumina particles were modified as shown in Table 1.

[0098] <Evaluation Method>

[0099] (1) Abrasion resistance A decorative panel was fabricated by bonding the base sheet of the decorative sheet to MDF using an emulsion-based adhesive. The decorative panel mentioned above was processed into a test piece size of 100mm x 100mm, and a 10mm hole was drilled in the center. The above test specimen was fixed to the rotating disc of a rotary abrasion resistance tester, wrapped with abrasive paper as specified in JIS A 1453:2015, and then two rubber discs as specified in JIS A 1453:2015 were attached. The above test specimen was checked every 100 rotations, and the abrasive paper was replaced every 200 rotations. This test was repeated. The tests were conducted until the initial pattern loss occurred, and evaluated according to the following criteria. <Evaluation Criteria> +++: The initial pattern loss occurred after more than 4200 spins. ++: The initial pattern loss occurred between 3600 and 4200 spins. +: The initial pattern loss occurred between 3000 and 3600 spins. -: The initial pattern loss occurred between 2000 and 3000 spins. --: The initial image loss occurred within 2000 spins. Furthermore, grades of "+++", "++", and "+" were considered passing grades, while grades of "-" and "--" were considered failing grades.

[0100] (2) Coating suitability The viscosity of the coating agent used in the production of the decorative sheet was measured using a Zahn cup No. 4 and evaluated according to the following criteria. +: Less than 40 seconds -: 40 seconds or more Furthermore, if the viscosity exceeds 40 seconds, coating defects occur, making it difficult to form a protective layer. Therefore, a "+" rating was judged as a pass, and a "-" rating was judged as a fail.

[0101] [Table 1]

[0102] Table 1 shows that in the example where the protective layer contains a cured product of a cross-linked curable resin and alumina particles, and the alumina particles contain electrofused alumina particles, it was confirmed that the abrasion resistance was excellent and coating defects could be suppressed. [Explanation of Symbols]

[0103] 1. Base sheet 2 Image Layers 3 Transparent resin layer 4 protective layer 5 Alumina particles 6 Uneven shape 7 Second protective layer 8a, 8b, 8c Adhesion auxiliary layer 9 Adhesive layer 10 Decorative sheets

Claims

1. A base sheet is provided with at least a protective layer, The protective layer contains a cured product of a cross-linked curable resin and alumina particles. The alumina particles are a decorative sheet containing electrofused alumina particles.

2. The decorative sheet according to claim 1, wherein the protective layer has a thickness of 30 μm or more and 80 μm or less.

3. The decorative sheet according to claim 1 or 2, wherein the cured product of the cross-linked curable resin is a cured product of an ionizing radiation curable resin.

4. The decorative sheet according to claim 1 or 2, wherein the electrofused alumina particles have an average particle diameter of 10 μm or more and 60 μm or less.

5. The aforementioned electrofused alumina particles have a heavy bulk density of 1.5 g / cm³. ３ 2.3g / cm or more ３ The decorative sheet according to claim 1 or 2, which is as follows:

6. The decorative sheet according to claim 1 or 2, wherein the electrofused alumina particles have a porosity of 1.0% or more and 7.0% or less.

7. The decorative sheet according to claim 1 or 2, wherein the electrofused alumina particles are spherical.

8. The decorative sheet according to claim 1 or 2, wherein the content of the electrofused alumina particles is 30% by mass or more and 100% by mass or less based on the total mass of the alumina particles.

9. The decorative sheet according to claim 1 or 2, wherein the protective layer contains alumina particles in an amount of 30% by mass or more and 100% by mass or less relative to the cured product of the crosslinked curable resin.

10. The decorative sheet according to claim 1 or 2, wherein the protective layer has an uneven shape on the side opposite to the side having the base sheet.

11. The decorative sheet according to claim 1 or 2, further comprising, between the base sheet and the protective layer, a pattern layer and a transparent resin layer, in order from the base sheet side.

12. The decorative sheet according to claim 1 or 2, wherein a second protective layer is provided on the side of the protective layer opposite to the side with the base sheet, and the second protective layer contains a cured product of an ionizing radiation-curable resin.

13. The decorative sheet according to claim 1 or 2, wherein the protective layer comprises a biomass-derived component.

14. A decorative panel comprising a decorative sheet according to claim 1 or 2 on a substrate.

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