Decorative sheets and decorative panels

Abstract

To provide a decorative sheet that is excellent in scratch resistance and abrasion resistance, and that can suppress damage to objects it comes into contact with. [Solution] A decorative sheet comprising a base sheet, a first protective layer, and at least a second protective layer on the side of the first protective layer opposite to the side of the base sheet, wherein the first protective layer and the second protective layer contain a cured product of a cross-linked curable resin, the first protective layer contains alumina particles, and the second protective layer does not contain alumina particles.

Description

Technical Field

[0001] The present invention relates to a decorative sheet and a decorative board.

Background Art

[0002] Decorative sheets with designs are used to decorate building materials, furniture, household appliances, etc.

[0003] In the case of a decorative sheet for decorating a floor, especially a decorative sheet for a floor used in areas with heavy walking, a protective layer containing alumina particles may be provided on the surface in order to improve scratch resistance and wear resistance.

[0004] For example, Patent Document 1 discloses an aspect in which a resin cured layer is provided on at least one surface side of a substrate, and the resin cured layer contains alumina particles.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the case of a decorative sheet for floor use in areas with heavy walking, attempts have been made to impart even better scratch resistance and wear resistance by increasing the amount of alumina particles added to the protective layer or increasing the average particle size of the alumina particles.

[0007] However, when the amount of alumina particles added to the protective layer is increased or the average particle size is increased, problems such as the alumina particles protruding from or falling off the protective layer, which impairs the design and smoothness, have occurred.

[0008] Furthermore, alumina particles that protruded from the protective layer could damage objects that came into contact with (or rubbed against) the decorative sheet.

[0009] Therefore, the present invention aims to provide a decorative sheet that is excellent in scratch resistance and abrasion resistance, and that can suppress damage to objects it comes into contact with. [Means for solving the problem]

[0010] The present inventors have found that by providing a base sheet with at least a first protective layer and a second protective layer on the side of the first protective layer opposite to the side of the base sheet, and by providing a cured product of a cross-linked curable resin in both the first and second protective layers, and by providing alumina particles in the first protective layer and not in the second protective layer, it is possible to suppress the protrusion and detachment of alumina particles from the protective layer, thereby obtaining a decorative sheet that is excellent in scratch resistance and abrasion resistance, and that can suppress damage to objects that come into contact with it, and thus completed the present invention.

[0011] In other words, the present invention provides a decorative sheet comprising a base sheet, a first protective layer, and a second protective layer on the side of the first protective layer opposite to the side of the base sheet, wherein the first protective layer and the second protective layer contain a cured product of a crosslinked curable resin, the first protective layer contains alumina particles, and the second protective layer does not contain alumina particles.

[0012] In the decorative sheet of the present invention, the first protective layer preferably has a thickness of 30 μm or more and 80 μm or less. Furthermore, it is preferable that the first protective layer contains a cured product of an ionizing radiation-curable resin. Furthermore, it is preferable that the average particle size of the alumina particles in the first protective layer is 10 μm or more and 60 μm or less. Furthermore, it is preferable that the content of the alumina particles in the first protective layer is 30% by mass or more and 100% by mass or less relative to the cured product of the cross-linked curable resin. Furthermore, the second protective layer described above preferably has a thickness of 10 μm or more and 40 μm or less. Furthermore, it is preferable that the second protective layer contains a cured product of an ionizing radiation-curable resin. Furthermore, it is preferable that the second protective layer contains an inorganic substance. Furthermore, it is preferable to have a pattern layer and a transparent resin layer between the base sheet and the first protective layer, in that order from the base sheet side. Furthermore, it is preferable that the second protective layer has an uneven shape on the side opposite to the side with the first protective layer. Furthermore, it is preferable that the side of the second protective layer opposite to the side with the first protective layer has a maximum peak height Sp of less than 20 μm and a crustosis Sku of 3 or less. Furthermore, it is preferable that at least one layer selected from the group consisting of the first protective layer and the second protective layer contains biomass-derived components. Furthermore, the present invention is also a decorative panel comprising the above-mentioned decorative sheet on a substrate. [Effects of the Invention]

[0013] The present invention provides a decorative sheet that is excellent in scratch resistance and abrasion resistance, and that can suppress damage to objects it comes into contact with. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic cross-sectional view illustrating a preferred example of the decorative sheet of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view illustrating another preferred example of the decorative sheet of the present invention. [Modes for carrying out the invention]

[0015] <Decorative sheet> The decorative sheet of the present invention comprises at least a first protective layer and a second protective layer on a base sheet, on the side of the first protective layer opposite to the side of the base sheet, the first protective layer and the second protective layer contain a cured product of a crosslinked curable resin, the first protective layer contains alumina particles, and the second protective layer does not contain alumina particles.

[0016] Figure 1 is a cross-sectional view schematically illustrating an example of the cosmetic sheet of the present invention. As shown in Figure 1, the cosmetic sheet 10 includes at least a first protective layer 4 on the base material sheet 1 and a second protective layer 6 on the side opposite to the base material sheet 1 of the first protective layer 4. In the cosmetic sheet 10, the first protective layer 4 contains alumina particles 5, and the second protective layer 6 does not contain alumina particles 5. Also, between the base material sheet 1 and the first protective layer 4, in order from the side of the base material sheet 1, a pattern layer 2 and a transparent resin layer 3 are provided. Furthermore, the cosmetic sheet 10 has an uneven shape 7 on the side opposite to the side provided with the base material sheet 1.

[0017] Figure 2 is a cross-sectional view schematically illustrating another preferable example of the cosmetic sheet of the present invention. As shown in Figure 2, the cosmetic sheet 10 includes at least a first protective layer 4 on the base material sheet 1 and a second protective layer 6 on the side opposite to the base material sheet 1 of the first protective layer 4. In the cosmetic sheet 10, the first protective layer 4 contains alumina particles 5, and the second protective layer 6 does not contain alumina particles 5. Note that the alumina particles 5 existing across both the first protective layer 4 and the second protective layer 6 (for example, the alumina particles 5 protruding from the first protective layer 4 in Figure 2) are regarded as being in the first protective layer 4. Also, between the base material sheet 1 and the first protective layer 4, in order from the side of the base material sheet 1, 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. Also, 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 material sheet 1 provided with the protective layer 4. Furthermore, the cosmetic sheet 10 has an uneven shape 7 on the side opposite to the side provided with the base material sheet 1. Hereinafter, each component of the cosmetic sheet of the present invention will be described in detail.

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

[0019] The first protective layer contains a cured product of a cross-linked curing 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 cross-linked curable resin used to form the first protective layer may also contain a biomass-derived resin. By including biomass-derived resin, the environmental impact can be reduced. As a biomass-derived resin, urethane (meth)acrylate and the like, which are composed of biomass-derived components, can be used. In the above-mentioned urethane (meth)acrylate, at least one component of the polyol, isocyanate compound, and hydroxy(meth)acrylate contained in the urethane (meth)acrylate is a biomass-derived component.

[0026] 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.

[0027] 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.

[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] From the viewpoint of appropriately imparting scratch resistance and abrasion resistance, the alumina particles preferably have an average particle diameter of 10 μm or more and 60 μm or less. In this specification, "average particle diameter" means the average particle diameter (arithmetic mean diameter) measured for 100 randomly selected non-aggregated particles when the cross-section of the decorative sheet in the thickness direction is observed with a scanning electron microscope (SEM). Furthermore, if the alumina particles are irregularly shaped, the calculation is performed using the equivalent diameter of the circumference. The average particle size of the alumina particles is more preferably 15 μm or larger, and even more preferably 20 μm or larger. Furthermore, it is more preferably 55 μm or smaller, and even more preferably 50 μm or smaller.

[0031] Alumina particles can be spherical, fibrous, plate-like, irregularly shaped, or flaky, but from the viewpoint of providing suitable scratch resistance and abrasion resistance, they are preferably spherical. Note that "spherical" may refer to a perfect sphere, a nearly spherical shape, a spheroid, etc.

[0032] From the viewpoint of appropriately imparting scratch resistance and abrasion resistance, and from the viewpoint of suppressing the shedding of alumina particles, the content of alumina particles 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.

[0033] The first protective layer may contain various additives such as colorants (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.

[0034] As a method for forming the first 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.

[0035] The first protective layer preferably has a thickness of 30 μm or more and 80 μm or less. By having the thickness of the first protective layer within the above range, scratch resistance and abrasion resistance can be suitably provided. The first protective layer is preferably 40 μm or more in thickness, and preferably 70 μm or less. Furthermore, if the uneven surface described later is formed, the thickness of the first protective layer is defined as the length from the area on the surface of the first protective layer where the uneven surface is not formed to the surface of the transparent resin layer of the first protective layer.

[0036] (Second protective layer) The decorative sheet of the present invention comprises a second protective layer.

[0037] The second protective layer contains a cured product of a cross-linked curing resin.

[0038] The second protective layer preferably contains a cured product of an ionizing radiation-curable resin. As the cross-linking curing resin and the ionizing radiation curing resin, you may appropriately select from those described in the first protective layer section.

[0039] The cross-linked curing resin used to form the second protective layer may also contain a biomass-derived resin. For the biomass-derived resin, you can select one of the options described in the first protective layer section as appropriate.

[0040] The second protective layer does not contain the alumina particles contained in the first protective layer. The alumina particles contained in the first protective layer refer to alumina particles of the same size (average particle diameter) and shape as those described for the alumina particles contained in the first protective layer.

[0041] The second protective layer preferably contains inorganic material.

[0042] Examples of inorganic materials include fine particles made from inorganic materials such as silica, glass, titania, zirconia, calcium carbonate, barium sulfate, and fine alumina (average particle size less than 10 μm, different from the alumina particles contained in the first protective layer).

[0043] The inorganic content is preferably 0.5% by mass or more and 25% by mass or less relative to the cured product of the cross-linked curable resin.

[0044] 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.

[0045] 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.

[0046] 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 of ​​the second protective layer where the uneven surface is not formed to the surface of the second protective layer on the first protective layer side.

[0047] On the side of the second protective layer opposite to the side with the first protective layer, it is preferable that the maximum peak height Sp is less than 20 μm and the crustosis Sku is 3 or less. If the maximum peak height Sp and kurtosis Sku are within the above range, the surface of the decorative sheet is smooth, and scratching of the object it comes into contact with can be effectively suppressed. On the side of the second protective layer opposite to the side with the first protective layer, the maximum peak height Sp is more preferably 18 μm or less, even more preferably 15 μm or less, and particularly preferably 13 μm or less. Furthermore, on the side of the second protective layer opposite to the side with the first protective layer, the kurtosis Sku is more preferably 2.7 or less, even more preferably 2.5 or less, and particularly preferably 2.4 or less. In this specification, the maximum peak height Sp and kurtosis Sku are based on ISO 25178 and were measured using a digital microscope (model: VHX-7000, magnification 200x, manufactured by Keyence Corporation) to measure the surface irregularities of the decorative sheet. The fact that the maximum peak height Sp and kurtosis Sku are kept within the above numerical range confirms, by measuring the surface irregularities, that the protrusion of the alumina particles is being controlled within an appropriate range.

[0048] (Base sheet) The decorative sheet of the present invention comprises a base sheet.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] (Picture layer) The decorative sheet of the present invention preferably includes a pattern layer.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] The thickness of the pattern layer is preferably, for example, 0.1 μm or more and 5 μm or less.

[0061] (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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] (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.

[0068] 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.

[0069] 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.

[0070] (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 first 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] (Uneven shape) From the viewpoint of suitably imparting aesthetic appeal, the decorative sheet of the present invention has an uneven shape on the side that has the second protective layer.

[0075] The uneven surface may extend to the transparent resin layer or the adhesive auxiliary layer (adhesive auxiliary layer 8b in Figure 2), or it may be a flat shape (a fine uneven surface).

[0076] The maximum height Rz of the uneven surface is preferably, 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).

[0077] 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 grooves, stone surface texture, fabric surface texture, and fine grooves.

[0078] (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.

[0079] 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.

[0080] 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.

[0081] The thickness of the backer layer is preferably, for example, 100 μm or more and 400 μm or less.

[0082] <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 first protective layer, and to provide a second protective layer on the side of the first 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 method for forming these layers may be the method described in the description of each layer.

[0083] 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), a first protective layer, and a second 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.

[0084] <Decorative panel> The decorative panel of the present invention comprises a decorative sheet of the present invention on a substrate.

[0085] 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.

[0086] This specification discloses the following:

[0087] (1) The present disclosure is a decorative sheet comprising a base sheet, a first protective layer and a second protective layer on the side of the first protective layer opposite to the side of the base sheet, wherein the first protective layer and the second protective layer contain a cured product of a crosslinked curable resin, the first protective layer contains alumina particles, and the second protective layer does not contain alumina particles. Disclosure (2) is a decorative sheet according to Disclosure (1), wherein the first protective layer has a thickness of 30 μm or more and 80 μm or less. Disclosure (3) is a decorative sheet according to Disclosure (1) or (2) wherein the first protective layer contains a cured product of an ionizing radiation-curable resin. Disclosure (4) is a decorative sheet according to any one of Disclosures (1) to (3), wherein the average particle size of the alumina particles in the first protective layer is 10 μm or more and 60 μm or less. Disclosure (5) is a decorative sheet according to any one of Disclosures (1) to (4), wherein the content of the alumina particles in the first protective layer is 30% by mass or more and 100% by mass or less relative to the cured product of the crosslinked curable resin. Disclosure (6) states that the second protective layer is a decorative sheet according to any of Disclosures (1) to (5), wherein the thickness is 10 μm or more and 40 μm or less. Disclosure (7) is a decorative sheet according to any one of Disclosures (1) to (6) wherein the second protective layer is a decorative sheet according to any one of Disclosures (1) to (6) containing a cured product of an ionizing radiation-curable resin. Disclosure (8) states that the second protective layer is a decorative sheet according to any of Disclosures (1) to (7) that contains an inorganic substance. The present disclosure (9) is a decorative sheet according to any one of the present disclosures (1) to (8), comprising, between the base sheet and the first protective layer, a pattern layer and a transparent resin layer in order from the base sheet side. Disclosure (10) is a decorative sheet according to any one of Disclosures (1) to (9) wherein the second protective layer has an uneven shape on the side opposite to the side having the first protective layer. (11) of this disclosure is a decorative sheet according to any one of (1) to (10) of this disclosure, wherein the side of the second protective layer opposite to the side having the first protective layer has a maximum peak height Sp of less than 20 μm and a kurtosis Sku of 3 or less. Disclosure (12) is a decorative sheet according to any one of Disclosures (1) to (11), wherein at least one layer selected from the group consisting of the first protective layer and the second protective layer contains a biomass-derived component. Disclosure (13) is a decorative panel comprising a decorative sheet described in any of Disclosures (1) to (12) on a substrate. [Examples]

[0088] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0089] (Example 1) A colored polypropylene sheet with a thickness of 60 μm was prepared as the base material. A back-side adhesive auxiliary layer, mainly composed of ester-based polyurethane resin, was formed on one side of the base sheet by solid printing of an organic solvent-containing ink 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 of the adhesive auxiliary layer (pattern auxiliary layer) opposite to the base sheet 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 first protective layer coating agent (urethane acrylate-based ionizing radiation-curable resin composition) containing alumina particles with a viscosity of 760 mPa·s as measured by an E-type rotational viscometer was applied to the adhesive auxiliary layer (surface adhesive auxiliary layer) using reverse coating. Then, a second protective layer coating agent (urethane acrylate-based ionizing radiation-curable resin composition) that does not contain alumina particles was applied, and the coating agents were cured by irradiation with ionizing radiation to form a first protective layer with a thickness of 50 μm and a second protective layer with a thickness of 30 μm, thereby manufacturing a decorative sheet. The average particle size of alumina particles, the maximum peak height Sp of the decorative sheet, and the kurtosis Sku listed in Table 1 were measured and calculated using the method described herein.

[0090] The composition of the coating agent used to form the first and second protective layers is as follows. (Coating agent for the first protective layer) Bifunctional urethane acrylate oligomer A (polyol component is polyester diol, Tg: 25℃, weight-average molecular weight: 1500) Content of ionizing radiation-curable resin (bifunctional urethane acrylate oligomer A): 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. (Coating agent for the second protective layer) 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

[0091] (Examples 2-3, Comparative Example 1) The decorative sheet was manufactured in the same manner as in Example 1, except that the average particle size of the alumina particles was changed as shown in Table 1. The average particle size of alumina particles, the maximum peak height Sp of the decorative sheet, and the kurtosis Sku listed in Table 1 were measured and calculated using the method described herein. Furthermore, in Table 1, "EB" in the "Types of Cross-linked Curing Resins" column refers to ionizing radiation curing resins, and "UV" refers to ultraviolet curing resins.

[0092] (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 for the first protective layer) Ultraviolet curable resin (weight average molecular weight: 1400, number of functional groups: 9, manufactured by Shin Nakamura Chemical Co., Ltd., UA-33H): 90 parts by mass, Photopolymerization initiator (BASF, Irgacure 184): 8 parts by mass UV absorber A (BASF, Tinuvin 326): 2 parts by mass UV absorber B (BASF, Tinuvin P): 2 parts by mass Light stabilizer (Sanol LS765, manufactured by BASF): 2.0 parts by mass Solvent (ethyl acetate): 60 parts by mass The alumina particles were as described in Table 1. (Coating agent for the second protective layer) Ultraviolet curable resin (weight average molecular weight: 1400, number of functional groups: 9, manufactured by Shin Nakamura Chemical Co., Ltd., UA-33H): 90 parts by mass, Photopolymerization initiator (BASF, Irgacure 184): 8 parts by mass UV absorber A (BASF, Tinuvin 326): 2 parts by mass UV absorber B (BASF, Tinuvin P): 2 parts by mass Light stabilizer (Sanol LS765, manufactured by BASF): 2.0 parts by mass Solvent (ethyl acetate): 60 parts by mass

[0093] (Example 5) The decorative sheet was manufactured in the same manner as in Example 1, except that the thickness of the second protective layer and the first protective layer, and the average particle size of the alumina particles were changed as shown in Table 1.

[0094] (Example 6) The decorative sheet was manufactured in the same manner as in Example 1, except that the thicknesses of the second protective layer and the first protective layer were changed as shown in Table 1.

[0095] (Example 7) The decorative sheet was manufactured in the same manner as in Example 1, except that the amount of alumina particles added was changed as shown in Table 1.

[0096] (Example 8) 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 for the first protective layer) Biomass-derived glycerin diacrylate A (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. (Coating agent for the second protective layer) Biomass-derived glycerin diacrylate A (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 In Table 1, "BO" in the "Types of Cross-linked Curing Resins" column refers to biomass-derived resins.

[0097] (Comparative Examples 2-4) A decorative sheet was manufactured in the same manner as in Example 1, except that a second protective layer was not formed and the average particle size of the alumina particles was changed 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) Scratch resistance A decorative panel was fabricated by bonding the base sheet of the decorative sheet to MDF using an emulsion-based adhesive. The above decorative panel was processed into test specimens measuring 75mm x 100mm. The above test specimens were fixed to scratch testing machines (Elcometer 3000 motor-driven type and manual Klemen hardness tester, manufactured by Elcometer, Inc.), and the surface of the decorative sheet (side of the second protective layer) was scratched 50 mm while applying load with a tungsten test needle with a diameter of 1 mm, and the scratch resistance was evaluated. The test was conducted at three load levels: 2 kg, 3 kg, and 4 kg. If the pattern was damaged or a gouge reached the base sheet occurred, the test was terminated and evaluated according to the following criteria. <Evaluation Criteria> Up to a load of ++: No fraying or damage occurred. Up to a load of +3kg, no fraying or damage occurred, but at a load of 4kg, the pattern was removed or gouges reaching the base sheet occurred. - Up to a load of 2 kg, no fuzzing or scratches occurred in the coating, but at a load of 3 kg, the pattern was removed and gouges that reached the base sheet occurred. --: A 2kg load caused the design to be damaged, resulting in a gouge that reached the base sheet. Furthermore, a rating of "++" or "+" was considered a pass, while a rating of "-" or "--" was considered a fail.

[0101] (3) Heel mark test A decorative panel was fabricated by bonding the base sheet of the decorative sheet to MDF using an emulsion-based adhesive. The above decorative panel was processed into test specimens measuring 100mm x 100mm. The above test specimens were attached to the side of the hexagonal prism drum inside the heel mark testing machine (JIS K 3920:2009). Next, six black rubber blocks were placed in the drum and rotated at 50 revolutions per minute for 5 minutes. Afterward, it was rotated in the opposite direction for 5 minutes, for a total test duration of 10 minutes. After the above tests, the test specimens were removed, and the degree of soiling on the surface of the specimens and the ease with which the soiling could be removed by wiping with a napped cotton cloth (flannel) were checked and evaluated according to the following criteria. <Evaluation Criteria> ++: All dirt on the surface of the test specimen can be removed by wiping it dry without applying any pressure. +: All dirt on the surface of the test specimen can be removed by wiping it firmly with a dry cloth. -: 70% of the dirt on the surface of the test specimen can be removed by wiping it firmly with a dry cloth. --: Dirt on the surface of the test specimen can be removed by vigorously wiping it with a dry cloth. Furthermore, a rating of "++" or "+" was considered a pass, while a rating of "-" or "--" was considered a fail.

[0102] [Table 1]

[0103] Table 1 shows that the decorative sheet of the example, which comprises a first protective layer and a second protective layer on a base sheet, and in which the first and second protective layers contain cured products of a cross-linked curable resin, and in which the first protective layer contains alumina particles, and the second protective layer does not contain the above alumina particles, exhibits excellent scratch resistance and abrasion resistance, and can suppress damage to objects it comes into contact with. [Explanation of Symbols]

[0104] 1. Base sheet 2 Image Layers 3 Transparent resin layer 4 1st protective layer 5 Alumina particles 6 Second protective layer 7 Uneven shape 8a, 8b, 8c Adhesion auxiliary layer 9 Adhesive layer 10 Decorative sheets

Claims

1. A base sheet is provided with a first protective layer and at least a second protective layer on the side of the first protective layer opposite to the side of the base sheet that is provided with the base sheet. The first protective layer and the second protective layer contain a cured product of a cross-linked curable resin. The first protective layer contains alumina particles, The second protective layer is a decorative sheet that does not contain the alumina particles.

2. The decorative sheet according to claim 1, wherein the first 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 first protective layer contains a cured product of an ionizing radiation-curable resin.

4. The decorative sheet according to claim 1 or 2, wherein the average particle size of the alumina particles in the first protective layer is 10 μm or more and 60 μm or less.

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

6. The decorative sheet according to claim 1 or 2, wherein the second protective layer has a thickness of 10 μm or more and 40 μm or less.

7. The decorative sheet according to claim 1 or 2, wherein the second protective layer contains a cured product of an ionizing radiation-curable resin.

8. The decorative sheet according to claim 1 or 2, wherein the second protective layer contains an inorganic substance.

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

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

11. The decorative sheet according to claim 1 or 2, wherein the side of the second protective layer opposite to the side with the first protective layer has a maximum peak height Sp of less than 20 μm and a kurtosis Sku of 3 or less.

12. The decorative sheet according to claim 1 or 2, wherein at least one layer selected from the group consisting of the first protective layer and the second protective layer contains a biomass-derived component.

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

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