Decorative sheet, decorative material, and method for producing decorative sheet

Abstract

To provide a decorative sheet excellent in impact resistance and abrasion resistance.SOLUTION: In the decorative sheet, a surface protective layer containing bubbles is laminated at least on a base sheet, where the surface protective layer is made of a cured product of an ionizing radiation-curable resin component, and a cross-sectional area occupancy of the enclosed bubbles is 5% or more and less than 30%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a decorative sheet, a decorative material, and a method for manufacturing a decorative sheet. [Background technology]

[0002] Decorative sheets for building materials are required to have excellent surface properties (impact resistance, abrasion resistance, etc.) so that they can withstand long-term use as surface decorative materials for residential interior materials, etc.

[0003] In order to satisfy these requirements, decorative sheets having a transparent resin layer that protects a picture layer (design layer) and a surface protective layer have been considered.

[0004] For example, Patent Document 1 discloses a decorative sheet having a first olefin resin layer (transparent resin layer), a second olefin resin layer (transparent resin layer), and a surface protective layer in that order, in which the second olefin resin layer and the surface protective layer have specific hardnesses. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-189905 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, decorative sheets are being required to have even better surface performance (such as impact resistance and abrasion resistance).

[0007] The present inventors have investigated methods for thickening the surface protective layer made of an ionizing radiation curable resin component in order to impart further surface performance to the decorative sheet. However, it has been found that while the thicker the surface protection layer, the harder it can be, the more flexibility is lost, resulting in a decrease in impact resistance.

[0008] SUMMARY OF THE INVENTION Accordingly, the present invention is intended to solve the above-mentioned problems, and has as its object to provide a decorative sheet that is excellent in impact resistance and abrasion resistance. [Means for solving the problem]

[0009] After extensive research, the inventors discovered that by forming the surface protective layer that constitutes the decorative sheet using a specific method and incorporating air bubbles within a specific range, it is possible to impart flexibility to the surface protective layer, thereby solving all of the above-mentioned problems, and thus completed the present invention.

[0010] The present invention is a decorative sheet comprising a base sheet and at least a surface protective layer containing bubbles laminated thereon, the surface protective layer being made of a cured product of an ionizing radiation curable resin component, and the cross-sectional area occupancy rate of the contained bubbles being 5% or more and less than 30%.

[0011] In the decorative sheet of the present invention, the thickness of the surface protective layer is preferably 60 μm or more and 200 μm or less. The average diameter of the bubbles contained in the surface protective layer is preferably 1 μm or more and 40 μm or less. The average diameter of the bubbles contained in the surface protective layer is preferably 10 μm or more and 20 μm or less. It is also preferable that a design layer, a transparent resin layer, and at least one primer layer are laminated in this order between the substrate sheet and the surface protective layer. The surface protection layer preferably has an irregular shape on the surface opposite to the base sheet. The uneven shape is preferably a wrinkled shape. It is also preferable that the surface protective layer further has a release film on the side opposite to the base sheet. The present invention also relates to a decorative material comprising a substrate and the decorative sheet of the present invention on the substrate. The present invention also relates to a method for producing a decorative sheet in which at least a surface protective layer is laminated on a base sheet, the method including a coating step of coating an ionizing radiation curable resin component at a viscosity of 40 seconds or more and 100 seconds or less as measured with a Zahn Cup No. 3. Furthermore, the method for producing a decorative sheet of the present invention preferably further comprises, after the coating step, a curing step of irradiating the ionizing radiation curable resin component with ionizing radiation and curing it within 10 seconds. [Effects of the Invention]

[0012] The present invention can provide a decorative sheet that is excellent in impact resistance and abrasion resistance. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view in the thickness direction showing a preferred example of the decorative sheet of the present invention. [Figure 2] FIG. 2 is a cross-sectional view in the thickness direction showing another preferred example of the decorative sheet of the present invention. [Figure 3] FIG. 3 is a cross-sectional view in the thickness direction showing another preferred example of the decorative sheet of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Decorative sheet> The decorative sheet of the present invention comprises a substrate sheet and a surface protective layer containing air bubbles laminated thereon, The surface protection layer is made of a cured product of an ionizing radiation curable resin component, and the cross-sectional area occupancy rate of the contained air bubbles is 5% or more and less than 30%.

[0015] FIG. 1 is a cross-sectional view in the thickness direction showing a preferred example of the decorative sheet of the present invention. As shown in FIG. 1, in the decorative sheet 10, a surface protective layer 6 containing air bubbles 7 is laminated on a base sheet 1. In addition, in the decorative sheet 10, it is preferable that a design layer 2, an adhesive layer 3, a transparent resin layer 4, and a primer layer 5 are laminated in this order between the base sheet 1 and the surface protective layer 6.

[0016] FIG. 2 is a cross-sectional view in the thickness direction showing another preferred example of the decorative sheet of the present invention. The decorative sheet 10 shown in Figure 2 is laminated with a base sheet 1, a pattern layer 2, an adhesive layer 3, a transparent resin layer 4, a primer layer 5, and a surface protection layer 6 containing air bubbles 7, similar to Figure 1. In the decorative sheet 10 of FIG. 2, the surface protective layer 6 has an uneven shape on the side opposite to the base sheet 1.

[0017] FIG. 3 is a cross-sectional view in the thickness direction showing another preferred example of the decorative sheet of the present invention. The decorative sheet 10 shown in Figure 3 is laminated with a base sheet 1, a pattern layer 2, an adhesive layer 3, a transparent resin layer 4, a primer layer 5, and a surface protection layer 6 containing air bubbles 7, similar to Figure 1. In the decorative sheet 10 of FIG. 3, the surface protective layer 6 has an uneven shape on the side opposite the base sheet 1, and furthermore, a release film 8 is laminated on the side of the surface protective layer 6 opposite the base sheet 1 side. Each layer that constitutes the decorative sheet 10 will now be described.

[0018] (Base sheet) The decorative sheet of the present invention comprises a base sheet.

[0019] Examples of the base sheet include polyester-based resins such as polyethylene terephthalate (PET); polyolefin-based resins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer resin, ethylene-propylene-butene copolymer resin, and olefin-based thermoplastic elastomer; polyurethane-based resins such as acrylic-modified urethane-based resin, polyester-modified urethane-based resin, and vinyl chloride-vinyl acetate copolymer-modified urethane-based resin; acrylic resins; polycarbonate-based resins; polystyrene-based resins; vinyl chloride-based resins, vinyl acetate-based resins, and vinyl chloride-vinyl acetate copolymer resins. Among these, polyethylene and polypropylene are preferred.

[0020] The substrate sheet may be colored as needed. The surface may be subjected to a surface treatment such as corona discharge treatment, plasma treatment, or ozone treatment, or may be coated with a primer, which is a base coating, to improve adhesion to adjacent layers.

[0021] The thickness of the substrate sheet is, for example, preferably 50 μm or more and 100 μm or less, and more preferably 60 μm or more and 80 μm or less.

[0022] (Surface protective layer) The decorative sheet of the present invention comprises at least a surface protective layer containing air bubbles laminated on the above-mentioned base sheet.

[0023] The surface protective layer is made of a cured product of an ionizing radiation curable resin component.

[0024] Examples of the cured product of the ionizing radiation curable resin component include cured products of oligomers and / or monomers having a radically polymerizable unsaturated group or a cationically polymerizable functional group in the molecule. The ionizing radiation refers to electromagnetic waves or charged particles having enough energy to polymerize or crosslink molecules, and is generally an electron beam (EB) or ultraviolet light (UV). The method for forming the surface protective layer is not particularly limited, and any known method can be used.

[0025] As the oligomer having a radically polymerizable unsaturated group or a cationically polymerizable functional group in the molecule, for example, oligomers such as urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, triazine (meth)acrylate, etc. can be preferably used, and urethane (meth)acrylate oligomers are more preferred. As for the molecular weight, those having a molecular weight of about 250 or more and 100,000 or less are usually used.

[0026] As the monomer having a radically polymerizable unsaturated group or a cationically polymerizable functional group in the molecule, for example, a polyfunctional monomer is preferred, and a polyfunctional (meth)acrylate is 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}, dipentaerythritol hexa(meth)acrylate {hexafunctional (meth)acrylate}, etc. Monofunctional monomers may also be used as appropriate.

[0027] When the ionizing radiation curable resin component is crosslinked by ultraviolet light, a photopolymerization initiator is preferably used. The amount of the photopolymerization initiator added is, for example, 0.1 to 10 parts by mass per 100 parts by mass of the ionizing radiation curable component.

[0028] In the surface protection layer, the cross-sectional area occupancy rate of the bubbles contained therein is 5% or more and less than 30%. When the cross-sectional area occupancy of the contained bubbles is within the above range, flexibility can be imparted to the surface protective layer, and impact resistance and abrasion resistance can be imparted to the decorative sheet. From the viewpoint of providing suitable impact resistance, the surface protective layer preferably has the encapsulated bubbles occupying a cross-sectional area of ​​7% or more, more preferably 10% or more, and even more preferably 15% or more, and the encapsulated bubbles occupying a cross-sectional area of ​​25% or less, more preferably 20% or less.

[0029] The cross-sectional area occupancy of the bubbles contained in the surface protective layer is measured and calculated by the following procedure.

[0030] (1) To observe the cross section of the decorative sheet in the thickness direction, an arbitrarily selected area is cut in the thickness direction of the decorative sheet with a sharp blade such as a single-edged trimming razor or a microtome. (2) A cross section of the cut decorative sheet in the thickness direction is observed with a digital microscope (width 1400 μm; "width" is the direction perpendicular to the thickness direction) to obtain a cross section photograph. (3) Using the "area measurement" function of the digital microscope's "measurement and scale" function, (a) the area of ​​the bubble (μm 2 ) and (b) the area (μm ) of the surface protection layer (width 1400 μm). 2 ) to calculate (4) From each calculated area, the ratio (occupancy rate) of the area occupied by the bubbles to the total area of ​​the cross section of the surface protection layer is calculated. Occupancy rate (%) = [a / b] × 100 (5) The above is performed for arbitrarily selected regions (10 locations), and the average value is defined as the cross-sectional area occupancy rate (%) of bubbles.

[0031] The equipment used to measure and calculate the cross-sectional area occupancy rate of the bubbles contained in the surface protective layer was a digital microscope (model number: VHX-7000, magnification 200x, manufactured by Keyence Corporation).

[0032] The average diameter of the bubbles contained in the surface protective layer is preferably 1 μm or more and 40 μm or less, from the viewpoint of providing the surface protective layer with suitable flexibility and obtaining a decorative sheet with excellent impact resistance. The average diameter of the bubbles contained in the surface protective layer is preferably 5 μm or more, more preferably 10 μm or more, and is preferably 30 μm or less, more preferably 20 μm or less.

[0033] The average diameter of the bubbles contained in the surface protective layer is measured and calculated by the following procedure.

[0034] (1) To observe the cross section of the decorative sheet in the thickness direction, an arbitrarily selected area is cut in the thickness direction of the decorative sheet with a sharp blade such as a single-edged trimming razor or a microtome. (2) A cross section (width 1400 μm; "width" is the direction perpendicular to the thickness direction) of the cut decorative sheet is observed with a digital microscope to obtain a cross section photograph. (3) Using the “area measurement” function of the digital microscope’s “measurement and scale” function, measure the area a of each bubble from the cross-sectional photograph. n (Width 1400μm) is calculated. (4) From each calculated area, calculate the diameter of a perfect circle (air bubble) that has the same area as each calculated area, and define this as the air bubble diameter (μm). Bubble diameter (μm) = (4a n / π) 1 / 2 (5) The average value of the diameters of the individual bubbles calculated by the above procedure is defined as the average bubble diameter (μm).

[0035] The device used to measure and calculate the average diameter of the bubbles contained in the surface protective layer was a digital microscope (model number: VHX-7000, magnification 200x, manufactured by Keyence Corporation).

[0036] The surface protection layer preferably has an irregular shape on the surface opposite to the base sheet. By having the above-described uneven shape, it is possible to impart design properties more favorably.

[0037] The uneven shape is preferably a wrinkled shape. When the uneven shape is a wrinkled shape, a matte effect can be imparted.

[0038] The above-mentioned uneven shape being a wrinkled shape means that the uneven shape is imparted by irregular wrinkles, and it is preferable that the irregular wrinkles have a plurality of convex portions formed by a plurality of protrusions and a concave portion formed by being surrounded by the plurality of protrusions.

[0039] The height of the convex portion is preferably, for example, 0.5 μm or more and 10 μm or less, and the width of the convex portion is preferably, for example, 10 μm or less.

[0040] The depth of the recess is preferably, for example, 0.5 μm or more and 10 μm or less, and the width of the recess is preferably, for example, 10 μm or less.

[0041] When the uneven shape has a wrinkled shape, the 60° gloss value is preferably, for example, 10.0 or less.

[0042] Examples of methods for forming the wrinkled shape include (1) performing irradiation treatment with light of a first wavelength of 100 nm or more and less than 200 nm, followed by (2) performing irradiation treatment with at least one of an electron beam and light of a second wavelength of 200 nm or more and 400 nm or less.

[0043] The thickness of the surface protective layer is preferably 60 μm or more, and more preferably 80 μm or more, from the viewpoint of increasing hardness and suitably imparting abrasion resistance. The thickness of the surface protective layer is preferably 200 μm or less, and from the viewpoint of providing suitable impact resistance, more preferably 150 μm or less.

[0044] When the surface protection layer does not have the above-mentioned uneven shape, the thickness of the surface protection layer is the length from the surface of the surface protection layer 6 opposite the base sheet 1 to the surface of the surface protection layer 6 on the base sheet 1 side, as shown in Figure 1. Furthermore, when the surface protection layer has the above-mentioned uneven shape, the thickness of the surface protection layer is the length from the outermost layer of the surface protection layer 6 where the uneven shape is not formed to the surface of the surface protection layer 6 on the base sheet 1 side, as shown in Figure 2.

[0045] (Picture layer) The decorative sheet of the present invention preferably comprises a design layer, a transparent resin layer, and at least one primer layer laminated in this order between the substrate sheet and the surface protective layer. First, the picture layer will be described.

[0046] The pattern layer can be formed with any desired pattern, such as wood grain, stone grain, sand grain, tiled pattern, brickwork pattern, fabric pattern, leather-striped pattern, geometric figures, letters, symbols, and abstract patterns.

[0047] The design layer can be formed by printing with a printing ink containing, for example, a polyvinyl resin, a polyester resin, an acrylic resin, a polyvinyl acetal resin, a cellulose resin, a polyurethane resin, or the like as a binder and a known pigment or dye as a colorant.

[0048] Methods for forming the design layer include known printing methods such as gravure printing, offset printing, silk screen printing, transfer printing from a transfer sheet, sublimation transfer printing, and ink jet printing.

[0049] The thickness of the design layer is preferably, for example, 0.1 μm or more and 10 μm or less.

[0050] (Transparent resin layer) Next, the transparent resin layer will be described. In the transparent resin layer, the term "transparency" means that the layer may be semi-transparent or colored, as long as the pattern layer can be seen.

[0051] Examples of the transparent resin layer include polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ionomer, polymethylpentene, acrylic acid ester, methacrylic acid ester, polycarbonate, and cellulose triacetate.

[0052] The thickness of the transparent resin layer is preferably, for example, 40 μm or more and 150 μm or less.

[0053] (Primer layer) The primer layer is not particularly limited, and a layer formed from a known primer agent can be used. Examples of the primer agent include a urethane resin-based primer agent made of an acrylic-modified urethane resin (acrylic urethane-based resin), a primer agent made of a urethane-cellulose-based resin (for example, a resin obtained by adding hexamethylene diisocyanate to a mixture of urethane and soluble nitrocellulose), and a resin-based primer agent made of an acrylic-urethane block copolymer.

[0054] The thickness of the primer layer is not particularly limited, but is preferably, for example, 0.5 μm or more and 10 μm or less.

[0055] The primer layer may be provided between the layers or on the opposite side of the substrate sheet from the surface protective layer.

[0056] (Release film) The decorative sheet of the present invention preferably further comprises a release film on the side of the surface protective layer opposite to the base sheet.

[0057] Examples of the release film include films made of polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polyolefin resins such as polypropylene and polyethylene; and polycarbonate resins.

[0058] The thickness of the release film is not particularly limited, but is preferably, for example, 10 μm or more and 100 μm or less.

[0059] The release film is preferably laminated on the surface protective layer via a release layer, if necessary, in order to improve the releasability from the surface protective layer. The release layer is peeled off and removed from the decorative sheet together with the release film when the release film is peeled off. Examples of the release layer that can be used include silicone resin, melamine resin, polyamide resin, urethane resin, polyolefin resin, wax, and the like, either alone or in combination. Furthermore, by providing the release film, the surface protective layer can be protected.

[0060] (others) The decorative sheet of the present invention may have an adhesive layer between each layer.

[0061] As the adhesive for forming the adhesive layer, for example, a urethane adhesive such as an ester urethane or an acrylic urethane, an acrylic adhesive, an epoxy adhesive, or a rubber adhesive can be used.

[0062] The thickness of the adhesive layer is, for example, 0.1 to 30 μm. The method for forming the adhesive layer is not particularly limited, and any known method may be appropriately selected.

[0063] The decorative sheet of the present invention may have a backer layer provided on the side of the substrate sheet opposite the surface protective layer. By providing the backer layer, impact resistance can be more suitably imparted.

[0064] The backer layer can be produced by molding the resin composition into a sheet (film) by a calendering method, an inflation method, a T-die extrusion method or the like.

[0065] The resin forming 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.

[0066] The thickness of the backer layer is preferably, for example, 100 μm or more and 350 μm or less.

[0067] Each layer constituting the decorative sheet of the present invention may contain additives as required. Examples of the additives include lubricants such as silicone resins, waxes, and fluororesins, colorants such as dyes and pigments, antioxidants, ultraviolet absorbers, light stabilizers, radical scavengers, flame retardants, deodorizers, antibacterial agents, antiviral agents, antiallergens, and antifungal agents. The amount of additives to be added can be appropriately determined depending on the product characteristics.

[0068] <Manufacturing method of decorative sheet> The method for producing a decorative sheet of the present invention is a method for producing a decorative sheet in which at least a surface protective layer is laminated on a base sheet, and includes a coating step in which an ionizing radiation curable resin component is applied in a state in which the viscosity at room temperature (20±5°C) measured with a Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.) is 40 seconds or more and 100 seconds or less.

[0069] By including the coating step, it is possible to uniformly disperse bubbles in the ionizing radiation curable resin component.

[0070] In the coating step, the viscosity of the ionizing radiation curable resin component at room temperature (20±5°C), measured with a Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.), is preferably 50 seconds or more, more preferably 60 seconds or more, and more preferably 80 seconds or less.

[0071] The viscosity of the ionizing radiation curable resin component measured with Zahn Cup No. 3 can be adjusted by stirring for 1 hour (after leaving to stand) in a room temperature (20°C) environment, and diluting with a solvent. Examples of the solvent include ethyl acetate, MEK (methyl ethyl ketone), IPA (isopropyl alcohol), toluene, MIBK (methyl isobutyl ketone), methanol, and butyl acetate.

[0072] The decorative sheet manufacturing method of the present invention preferably further comprises, after the coating step, a curing step of irradiating the ionizing radiation curable resin component with ionizing radiation and curing it within 10 seconds.

[0073] As in the curing step, by irradiating the ionizing radiation curable resin component with ionizing radiation and curing it within 10 seconds, it is possible to incorporate air bubbles into the surface protective layer. The time required for the ionizing radiation curable resin component to harden is preferably within 5 seconds, more preferably within 2 seconds. As the ionizing radiation, ultraviolet rays or electron beams may usually be used, but visible light, X-rays, ion beams, etc. may also be used. Any light intensity can be used for curing as long as it can be cured within 5 seconds, but when curing with ultraviolet light, it is preferable that the wavelength is 200 nm or more and 400 nm or less.The preferred electron beam irradiation dose is 0.1 to 30 Mrad, using electrons with an energy of 100 to 300 keV.

[0074] When a surface protective layer is formed on the surface of the base sheet, a coating step and a curing step can be performed on the surface of the base sheet. When a surface protective layer is formed on the surface of a primer layer formed on a transparent resin layer, as shown in Figure 1, a coating step and a curing step can be performed on the surface of the primer layer.

[0075] Each layer (transparent resin layer) constituting the decorative sheet of the present invention may be laminated via the adhesive layer or primer layer. The design layer may be formed on the base sheet by the method for forming the design layer. Furthermore, the uneven shape may be formed on the side having the surface protective layer by the method described above for the surface protective layer.

[0076] <Decorative materials> The decorative material of the present invention comprises the decorative sheet of the present invention on a substrate.

[0077] Examples of the substrate include wood boards, gypsum boards, cement boards, ceramic boards, metal boards, resin boards, and fiber-reinforced plastic boards.

[0078] The decorative sheet of the present invention may be laminated on the substrate by, for example, laminating it via the adhesive described above for the adhesive layer.

[0079] The present specification discloses the following:

[0080] The present disclosure (1) is a decorative sheet in which at least a surface protective layer containing bubbles is laminated on a base sheet, the surface protective layer being made of a cured product of an ionizing radiation curable resin component, and the cross-sectional area occupancy rate of the contained bubbles is 5% or more and less than 30%. The present disclosure (2) is the decorative sheet according to the present disclosure (1), wherein the thickness of the surface protective layer is 60 μm or more and 200 μm or less. The present disclosure (3) is the decorative sheet according to the present disclosure (1) or (2), wherein the average diameter of the bubbles contained in the surface protective layer is 1 μm or more and 40 μm or less. The present disclosure (4) is the decorative sheet according to the present disclosure (3), wherein the average diameter of the bubbles contained in the surface protective layer is 10 μm or more and 20 μm or less. The present disclosure (5) is a decorative sheet according to any one of the present disclosures (1) to (4), in which a pattern layer, a transparent resin layer, and at least one primer layer are laminated in this order between the substrate sheet and the surface protective layer. The present disclosure (6) is the decorative sheet according to any one of the present disclosures (1) to (5), wherein the surface protective layer has an uneven shape on the surface opposite to the base sheet. The present disclosure (7) is the decorative sheet according to any one of the present disclosures (1) to (6), wherein the uneven shape is a wrinkled shape. The present disclosure (8) is the decorative sheet according to any one of the present disclosures (1) to (7), further comprising a release film on the side of the surface protective layer opposite to the base sheet. The present disclosure (9) is a decorative material comprising a substrate and the decorative sheet of the present invention on the substrate. The present disclosure (10) is a method for producing a decorative sheet in which at least a surface protective layer is laminated on a base sheet, the method including a coating step of coating an ionizing radiation curable resin component in a state in which the viscosity measured with Zahn Cup No. 3 is 40 seconds or more and 100 seconds or less. The present disclosure (11) is a method for producing a decorative sheet according to the present disclosure (10), further comprising, after the coating step, a curing step of irradiating the ionizing radiation curable resin component with ionizing radiation to cure it within 10 seconds. [Example]

[0081] The present invention will now be described in more detail with reference to examples, but is not limited to these examples.

[0082] Example 1 As a substrate sheet, a colored polypropylene sheet having a thickness of 60 μm was prepared. A primer layer mainly composed of an ester-based polyurethane resin was formed on one side of the substrate sheet so as to cover the entire surface by solid printing with an ink containing an organic solvent using a gravure printing method using an intaglio roll. On the other side of the substrate sheet, a design layer mainly composed of an acrylic-urethane resin was formed by solid printing with an ink containing an organic solvent by gravure printing using an intaglio roll. An ester-based polyurethane was applied to the surface of the design layer opposite the substrate sheet to form an adhesive layer having a thickness of 10 μm, and a 60 μm transparent resin layer was formed on the adhesive layer by dry lamination. Furthermore, a 2 μm-thick primer layer made of an acrylic-urethane copolymer resin was formed on the side of the transparent resin layer opposite the adhesive layer. A surface protective layer composition (urethane acrylate-based ionizing radiation-curable resin composition) with a viscosity at room temperature (20±5°C) measured with a Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.) of 40 seconds (abbreviated as "Zahn Cup viscosity" in the tables) was then applied onto this primer layer using a die coater, and the composition was then exposed to ionizing radiation for instantaneous curing (within 10 seconds) to form a 100 μm-thick surface protective layer, thereby producing a decorative sheet.

[0083] Example 2 A decorative sheet was manufactured in the same manner as in Example 1, except that the composition for the surface protection layer in Example 1 was changed to a composition for the surface protection layer (urethane acrylate-based ionizing radiation curable resin composition) having a viscosity of 60 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.).

[0084] Example 3 A decorative sheet was manufactured in the same manner as in Example 1, except that the composition for the surface protection layer in Example 1 was changed to a composition for the surface protection layer (urethane acrylate-based ionizing radiation curable resin composition) having a viscosity of 80 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.).

[0085] Example 4 The composition for the surface protective layer in Example 1 was changed to the following composition, and the composition was instantly cured (within 10 seconds) using a high-pressure mercury lamp to form a surface protective layer. ·UV 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 weight Product name: Irgacure 184 (manufactured by BASF) UV absorber A: 2 parts by weight Product name: Tinuvin 326 (manufactured by BASF) UV absorber B: 2 parts by weight Product name: Tinuvin P (manufactured by BASF) Light stabilizer: 2 parts by weight Product name: Sanol LS765 (manufactured by BASF) A decorative sheet was manufactured in the same manner as in Example 1, except that a surface protective layer was formed using the above-mentioned surface protective layer composition, which had a viscosity of 60 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.).

[0086] Example 5 A decorative sheet was manufactured in the same manner as in Example 1, except that the surface protection layer composition in Example 1 was changed to a surface protection layer composition (urethane acrylate-based ionizing radiation curable resin composition) having a viscosity of 80 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.), and a surface protection layer 200 μm thick was formed.

[0087] (Comparative Example 1) A decorative sheet was manufactured in the same manner as in Example 1, except that the composition for the surface protection layer in Example 1 was changed to a composition for the surface protection layer (urethane acrylate-based ionizing radiation curable resin composition) having a viscosity of 140 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.).

[0088] (Comparative Example 2) A decorative sheet was manufactured in the same manner as in Example 1, except that the composition for the surface protection layer in Example 1 was changed to a composition for the surface protection layer (urethane acrylate-based ionizing radiation curable resin composition) having a viscosity of 20 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.).

[0089] (Comparative Example 3) A decorative sheet was manufactured in the same manner as in Example 1, except that the composition for the surface protection layer in Example 1 was changed to a composition for the surface protection layer (urethane acrylate-based ionizing radiation curable resin composition) having a viscosity of 180 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.).

[0090] Comparative Example 4 A decorative sheet was manufactured in the same manner as in Example 1, except that the composition for the surface protection layer in Example 1 was changed to a composition for the surface protection layer (urethane acrylate-based ionizing radiation curable resin composition) having a viscosity of 30 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.).

[0091] (Comparative Example 5) The composition for the surface protective layer in Example 1 was changed to the following composition, and after coating, it was dried at 60°C for 1 minute and then cured by aging at 40°C for 3 days to form a surface protective layer. Thermosetting resin (100 parts by mass of acrylic polyol, 15 parts by mass of hexanemethylene diisocyanate as a curing agent): 100 parts by mass UV absorber A: 2 parts by weight Product name: Tinuvin 326 (manufactured by BASF) UV absorber B: 2 parts by weight Product name: Tinuvin P (manufactured by BASF) Light stabilizer: 2 parts by weight Product name: Sanol LS765 (manufactured by BASF) A decorative sheet was manufactured in the same manner as in Example 1, except that the surface protective layer was formed by the above-mentioned thermal curing using the above-mentioned surface protective layer composition, which had a viscosity of 40 seconds at room temperature (20±5°C) as measured using Zahn Cup No. 3 (manufactured by Rigo Co., Ltd.).

[0092] <Cross-sectional area occupancy of bubbles contained in the surface protection layer> Using the method described in this specification, the cross-sectional area occupancy of the bubbles contained in the surface protective layer of each decorative sheet was measured and calculated. The results are shown in Table 1. In Table 1, this is abbreviated as "cross-sectional area occupancy."

[0093] <Average diameter of bubbles contained in the surface protection layer> The average diameter of the bubbles contained in the surface protective layer of each decorative sheet was measured and calculated using the method described in this specification. The results are shown in Table 1. In Table 1, this is abbreviated as "average diameter."

[0094] <Production of test decorative materials> The side of the produced decorative sheet having the surface protective layer and the opposite side were attached to MDF (thickness 3 mm) using a urethane-modified emulsion adhesive (isocyanate-based curing agent) to prepare a test decorative material.

[0095] <Impact resistance> The test was carried out using a DuPont impact tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in the following manner. The test decorative material was placed between the impact point with a diameter of 6.3 mm and the impact point support, and a 500 g weight was dropped from heights of 10 cm, 20 cm, and 30 cm. Thereafter, the surface of the test decorative material (the surface on the decorative sheet side) was visually inspected for cracks and evaluated according to the following criteria. The results are shown in Table 1. (Evaluation criteria) ++: No cracks were observed in the decorative sheet in any of the tests at drop heights of 10 cm, 20 cm, and 30 cm. +: No cracks were observed in the decorative sheet when dropped from a height of 10cm or 20cm, but cracks were observed in the decorative sheet when dropped from a height of 30cm. -: No cracks were observed in the sheet when dropped from a height of 10 cm, but cracks were observed in the decorative sheet in both the 30 cm and 20 cm tests. --: Cracks were observed in the decorative sheet in all tests, with drop heights of 10cm, 20cm, and 30cm.

[0096] <Wear resistance> The test decorative material was cut into a test piece size of 100 mm x 100 mm, and a 10 mm hole was drilled in the center. The test piece was fixed to the rotating plate of a rotary abrasion resistance tester, and two rubber disks specified in JIS A 1453:2015 wrapped with abrasive paper specified in JIS A 1453:2015 were attached to evaluate the abrasion resistance. The test was repeated, rotating at 100 revolutions per minute and replacing the abrasive paper at 200 revolutions per minute, until the initial pattern removal occurred, and the test was evaluated according to the following criteria. (Evaluation criteria) +: The initial pattern capture occurred after more than 1000 spins. -: The initial pattern capture occurred after more than 500 spins but less than 1000 spins. --: The initial pattern capture occurred within 500 spins.

[0097] [Table 1]

[0098] It was confirmed that the decorative sheets in the examples had excellent impact resistance and abrasion resistance. [Explanation of symbols]

[0099] 1 Base sheet 2. Picture layer 3 Adhesive layer 4 Transparent resin layer 5 Primer layer 6 Surface protective layer 7. Bubbles 8 Release film 10 Decorative Sheet

Claims

1. At least a surface protection layer containing air bubbles is laminated on a substrate sheet, The decorative sheet, wherein the surface protective layer is made of a cured product of an ionizing radiation curable resin component, and the cross-sectional area occupancy rate of the contained air bubbles is 5% or more and less than 30%.

2. 2. The decorative sheet according to claim 1, wherein the thickness of the surface protective layer is 60 μm or more and 200 μm or less.

3. 3. The decorative sheet according to claim 1, wherein the average diameter of the bubbles contained in said surface protective layer is 1 μm or more and 40 μm or less.

4. 4. The decorative sheet according to claim 3, wherein the average diameter of the bubbles contained in said surface protective layer is 10 μm or more and 20 μm or less.

5. 3. The decorative sheet according to claim 1, further comprising a design layer, a transparent resin layer, and at least one primer layer laminated in this order between the substrate sheet and the surface protective layer.

6. 3. The decorative sheet according to claim 1, wherein the surface protective layer has an uneven shape on the surface opposite to the base sheet.

7. 7. The decorative sheet according to claim 6, wherein the uneven shape is a wrinkled shape.

8. 3. The decorative sheet according to claim 1, further comprising a release film on the surface protective layer opposite to the base sheet.

9. A decorative material comprising the decorative sheet according to claim 1 or 2 on a substrate.

10. A method for producing a decorative sheet in which at least a surface protective layer is laminated on a base sheet, comprising: A method for producing a decorative sheet, comprising a coating step of applying an ionizing radiation curable resin component in a state where the viscosity measured with a Zahn Cup No. 3 is 40 seconds or more and 100 seconds or less.

11. The method for producing a decorative sheet according to claim 10, further comprising, after the coating step, a curing step of irradiating the ionizing radiation curable resin component with ionizing radiation and curing it within 10 seconds.

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