Laminated sheet

Abstract

The objective is to provide a laminated sheet that exhibits excellent balance of surface irregularities, small variation in glossiness, and suppresses changes in the appearance of the surface layer even when the viewing angle of the surface layer is changed. [Solution] The laminated sheet 1 comprises a base material 2 and a surface layer 3 provided on the surface 2a of the base material 2, and the surface 3a of the surface layer 3 has valleys 4 and peaks 5 in accordance with ISO 25178-2:2021. The following relationships (1) to (2) hold between the maximum valley depth Sv of the valleys 4 in accordance with ISO 25178-2:2021 and the maximum peak height Sp of the peaks 5 in accordance with ISO 25178-2:2021. [Mathematics 1] 1.50 μm <Sv<8.50μm (1) [Math 2] 0.40

Description

[Technical Field]

[0001] This invention relates to a laminated sheet. [Background technology]

[0002] Laminated sheets are used to enhance the aesthetic appeal of various applications, such as wall coverings, joinery materials, fixtures and fittings, surface decoration of furniture, and exterior finishes for automobile interiors and low-voltage electrical equipment. Examples of such laminated sheets include those with a low-gloss (matte) layer on a base material.

[0003] For example, a laminated sheet has been proposed comprising a base material and a surface layer provided on the surface of the base material, wherein the surface layer contains a matting agent such as mica, silica, alumina, or calcium carbonate (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-062081 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in the laminated sheet described in Patent Document 1 above, as the content of the matting agent increases, the particles constituting the matting agent aggregate, which reduces the balance of the uneven shape on the surface of the surface layer. As a result, there is a problem in that the variation in the glossiness of the surface layer increases, and the appearance of the surface layer changes greatly when the viewing angle of the surface layer is changed.

[0006] Therefore, the present invention has been made in view of the above problems, and aims to provide a laminated sheet that has excellent balance of unevenness on the surface of the surface layer, has little variation in glossiness of the surface layer, and can suppress changes in the appearance of the surface layer even when the viewing angle of the surface layer is changed. [Means for solving the problem]

[0007] To achieve the above objective, the laminated sheet of the present invention comprises a base material and a surface layer provided on the surface of the base material, wherein the surface of the surface layer has valleys and peaks in accordance with ISO 25178-2:2021, and the relationship between the maximum valley depth Sv in accordance with ISO 25178-2:2021 and the maximum peak height Sp in accordance with ISO 25178-2:2021 is characterized by the following relationship (1) to (2).

[0008] [Mathematics 1] 1.50 μm <Sv<8.50μm (1)

[0009] [Math 2] 0.40 <Sv / (Sv+Sp)<0.65 (2) [Effects of the Invention]

[0010] The present invention makes it possible to provide a laminated sheet that suppresses variations in the glossiness of the surface layer and suppresses changes in the appearance of the surface layer even when the viewing angle of the surface layer is changed. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing a laminated sheet according to an embodiment of the present invention. [Figure 2] This is a laser microscope image showing the surface condition of the surface layer in the laminated sheet of Example 1. [Modes for carrying out the invention]

[0012] The laminated sheet of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments, and can be modified and applied as appropriate without altering the essence of the invention.

[0013] <Laminated sheet> As shown in Figure 1, the laminated sheet 1 of the present invention comprises a base material 2 and a surface layer 3 provided on the surface 2a of the base material 2.

[0014] <Base material> The base material 2 is formed of, for example, a thermoplastic resin sheet, and as this thermoplastic resin sheet, those generally used as a base material in a laminated sheet 1 can be used. Specific examples thereof include a polyvinyl chloride (PVC) sheet, a glycol-modified polyethylene terephthalate (PETG) sheet, an amorphous crystalline polyester resin (APET) sheet, a polyolefin sheet (a polyethylene sheet, a polypropylene sheet, etc.), an acrylonitrile-butadiene-styrene resin (ABS) sheet, a polycarbonate sheet, and the like. Further, examples of the amorphous crystalline polyester resin (APET) sheet used for the base material 2 include a recycled polyethylene terephthalate (RPET) sheet made from raw materials such as PET bottles.

[0015] In addition, as the thermoplastic resin sheet, a polyvinyl chloride sheet is preferred from the viewpoints of facilitating quadratic surface processing and being excellent in three-dimensional moldability.

[0016] Further, the thermoplastic resin sheet may be a stretched sheet or an unstretched sheet. In addition, the thermoplastic resin sheet may contain additives such as colorants, ultraviolet absorbers, hindered amine light stabilizers, antioxidants, antistatic agents, storage stabilizers, lubricants, and fillers as necessary. In addition, it is preferable that the thermoplastic resin sheet is colored from the viewpoint of designability.

[0017] The thickness of the base material 2 is not particularly limited, but is preferably 50 to 800 µm, more preferably 250 to 500 µm. If the thickness of the base material 2 is 50 µm or more, mechanical strength and hiding properties can be sufficiently improved. Further, if the thickness of the base material 2 is 800 µm or less, the three-dimensional moldability is more excellent, and it becomes easier to ensure flexibility and printability.

[0018] <Surface layer> The surface layer 3 is formed of a transparent resin or a coating film. The reason for using the surface layer 3 formed of a transparent resin is that from the viewpoint of designability, a layer that is transparent to an extent that does not hide the colored or printed surface of the base material 2 is desirable. Further, when the surface layer 3 is formed of a transparent resin, irregularities are formed by a method such as embossing with an embossing roll.

[0019] The transparent resin only needs to be a resin that is transparent to an extent that does not hide the surface of the base material 2, and examples thereof include vinyl chloride resin and PET resin to which no pigment is added. These resins may be used alone, or two or more kinds thereof may be used in combination. Further, the transparent resin may contain other components within a range that does not impair the effects of the invention.

[0020] When the surface layer 3 is formed of a coating film of a coating material containing urethane acrylate as a main component, the surface layer 3 can be formed by applying the coating material onto the surface 2a of the base material 2 and curing it with ultraviolet light, and the surface layer 3 is formed of a cured product of the coating material. Further, as shown in FIG. 1, irregularities (wrinkles) are formed on the surface 3a of the surface layer 3 (that is, the surface on the opposite side from the base material 2 side).

[0021] As urethane acrylates, those with 2 to 10 functionalities are used, such as phenylglycidyl ether acrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, and dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer. Also, EBECRYL8402, KRM8452, EBECRYL210, EBECRYL220, EBECRYL4500, EBECRYL230, EBECRYL270, EBECRYL4858, EBECRYL8804, EBECRYL8807, EBECRYL9270, EBECRYL4100, EBECRYL4666, EBECRYL4513, EBECRYL8311, EBECRYL8465, EBECRYL9260, EBECRYL8606, EBEC Commercially available products such as RYL8701, KRM8667, EBECRYL4265, EBECRYL4587, EBECRYL4200, EBECRYL8210, EBECRYL1290, EBECRYL5129, EBECRYL8254, EBECRYL8301R, KRM8200, KRM8904, U-6LPA, UA-1100H, U-200PA, UA-160TM, UV-3300B, UV-6630B, and UV-7620EA (all product names) can be used. These urethane acrylates may be used individually or in combination of two or more types.

[0022] Furthermore, the surface layer 3 may contain a monofunctional acrylate. Examples of monofunctional acrylates include ethyl carbitol acrylate, methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, β-(meth)acryloyloxyethyl hydrogen phthalate, β-(meth)acryloyloxyethyl hydrogen succinate, nonylphenoxyethyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxypolyethylene glycol. (meth)acrylate, butoxypolyethylene glycol (meth)acrylate, alkyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxyethylphthalic acid 3-Acryloyloxyglycerin mono(meth)acrylate, 2-Hydroxybutyl(meth)acrylate, 2-Hydroxy-1-(meth)acryloxy-3-(meth)acryloxypropane, Polypropylene glycol mono(meth)acrylate, Polyethylene glycol mono(meth)acrylate, Poly-ε-Caprolactone mono(meth)acrylate, Dialkylaminoethyl(meth)acrylate, Glycidyl(meth)acrylate, Mono[2-(meth)acryloyloxyethyl]acid phosphate Examples include trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 2,2,3,4,4,4-hexafluorobutyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, dicyclopentenyloxyalkyl (meth)acrylate, dicyclopentenyl (meth)acrylate, tricyclodecanyl (meth)acrylate, tricyclodecanyloxyethyl (meth)acrylate, and isobornyloxyethyl (meth)acrylate. These monofunctional acrylates may be used individually or in combination of two or more.

[0023] Furthermore, the mixing ratio of urethane acrylate to monofunctional acrylate in the surface layer 3 is not particularly limited as long as it does not impair the characteristics of the laminated sheet 1 of the present invention. For example, the mass ratio of urethane acrylate to monofunctional acrylate can be in the range of 1:0.5 to 1:4.

[0024] Furthermore, the thickness of the surface layer 3 is not particularly limited, but when formed as a coating film, 1 to 10 μm is preferred. This is because if the thickness of the surface layer 3 is 10 μm or more, the surface roughness of the surface 3a of the surface layer 3 increases, which improves fingerprint resistance but may reduce tactile sensitivity.

[0025] Furthermore, the paint may contain other components besides urethane acrylate and monofunctional acrylate, to the extent that it does not impair the effects of the invention. Examples of other components include polyfunctional acrylate, vinyl chloride-vinyl acetate copolymer, silicone acrylate, photopolymerization initiator, colorant, ultraviolet absorber, hindered amine-based light stabilizer, antioxidant, antistatic agent, preservative stabilizer, plasticizer, lubricant, filler, and the like.

[0026] Examples of polyfunctional acrylates include dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, EBECRYL145, EBECRYL150, IRR214K, EBECRYL130, trimethylolpropane triacrylate, EBECRYL160S, OTA480, PETIA, PETRA, EBECRYL40, PETA, EBECRYL140, EBECRYL1140, EBECRYL1142, DPHA, EBECRYL895, EBECRYL896, ethoxyca bisphenol A diacrylate, and glycerin triacrylate. These polyfunctional acrylates may be used individually or in combination of two or more types.

[0027] Examples of photopolymerization initiators that can be used include alkylphenone-based, acylphosphine oxide-based, and cationic initiators.

[0028] <Manufacturing method> When manufacturing the laminated sheet 1 of the present invention, first, a base material 2 made of the above-mentioned thermoplastic resin sheet is prepared. This thermoplastic resin sheet may be a commercially available product, or it may be manufactured by a known manufacturing method such as the calendering method or extrusion molding method.

[0029] Next, a coating is applied to the surface 2a of the substrate 2, which contains a solvent such as methyl ethyl ketone, to which, for example, urethane acrylate, monofunctional acrylate, polyfunctional acrylate, silicone acrylate, vinyl chloride-vinyl acetate copolymer, and a photopolymerization initiator is added, thereby forming a coating film that will become the surface layer 3 on the surface 2a of the substrate 2.

[0030] Furthermore, for example, when using a 2- to 10-functional urethane acrylate containing a photopolymerization initiator, the use of a monofunctional acrylate can be omitted.

[0031] Furthermore, the method of coating the paint is not particularly limited and includes, for example, the cast coating method, die coating method, gravure coating method, roll knife coating method, reverse roll coating method, roll coating method, and comma coating method.

[0032] Next, the coating film formed on the surface 2a of the substrate 2 is irradiated with excimer light. More specifically, the coating film is irradiated with excimer light having a short peak wavelength (in the range of 120 to 230 nm).

[0033] Furthermore, when irradiating with excimer light using an excimer lamp, the peak wavelength of the electromagnetic wave can be changed by changing the discharge gas filled in the excimer lamp. Examples of discharge gases used to irradiate with excimer light of the above peak wavelength include Ar 2 , Kr 2 Xe 2 The following can be used.

[0034] Then, by irradiating the coating with ultraviolet light (350-450 nm) to cure it, a surface layer 3, which is an ultraviolet-cured material, is formed on the surface 2a of the substrate 2, as shown in Figure 1, and a laminated sheet 1 is manufactured in which irregularities (wrinkles) are formed on the surface 3a of the surface layer 3.

[0035] Furthermore, even if the coating is irradiated again with excimer light (within the range of 120-230 nm) instead of the ultraviolet light (350-450 nm) mentioned above, the coating will not completely harden.

[0036] Then, by irradiating the coating film with the excimer light described above, hardening occurs only on the outermost surface of the coating film, creating non-uniformity between the surface and the interior of the coating film. As a result, coating components move from the unreacted parts inside the coating film to the surface, causing irregularities (wrinkles) to form on the surface of the coating film, and consequently making it possible to control the gloss level of the surface layer 3.

[0037] Furthermore, in the laminated sheet 1 of the present invention, as shown in Figure 1, the surface 3a of the surface layer 3 has valleys 4 and peaks 5 in accordance with ISO 25178-2:2021, and when the maximum valley depth of the valleys 4 in accordance with ISO 25178-2:2021 is Sv and the maximum peak height of the peaks 5 in accordance with ISO 25178-2:2021 is Sp, the following relationships (3) to (4) hold.

[0038] [Math 3] 1.50 μm <Sv<8.50μm (3)

[0039] [Math 4] 0.40 <Sv / (Sv+Sp)<0.65 (4)

[0040] Furthermore, in the present invention, by controlling the maximum valley depth Sv of the valley 4 and the maximum peak height Sp of the peak 5 so that the relationship shown in equations (3) to (4) above holds, the balance of the uneven shape on the surface 3a of the surface layer 3 is improved, thereby reducing the variation in glossiness on the surface 3a of the surface layer 3. Therefore, even when the viewing angle of the surface 3a of the surface layer 3 is changed, it becomes possible to suppress changes in the appearance of the surface layer 3.

[0041] Furthermore, if the maximum groove depth Sv is large, it becomes more difficult to remove dirt and the resistance to contamination decreases. Therefore, the range of the maximum groove depth Sv for groove 4 is preferably 5.9 μm to 8.0 μm.

[0042] Furthermore, if the maximum peak height Sp is large, roughness will occur on the tactile surface; therefore, the range of the maximum peak height Sp of peak 5 is preferably 3.8 μm to 7.5 μm.

[0043] Furthermore, "maximum peak height Sp" represents the maximum height from the average surface (reference surface) of the surface in the measurement area (definition area), and can be determined in accordance with ISO 25178-2:2021 by the method described in the examples below.

[0044] Furthermore, "maximum valley depth Sv" represents the absolute value of the minimum height from the average surface (reference surface) of the surface in the measurement area (definition area), and can be determined in accordance with ISO 25178-2:2021 by the method described in the examples below.

[0045] Furthermore, in the laminated sheet 1 of the present invention, as described above, the relationships in equations (3) to (4) above hold true, and variations in glossiness on the surface 3a of the surface layer 3 can be suppressed. Therefore, if the 85° glossiness of the surface 3a of the surface layer 3 is A and the 20° glossiness of the surface 3a of the surface layer 3 is B, the relationship in equation (5) below holds true, and the difference between the glossiness when viewed at an 85° angle to the surface 3a of the surface layer 3 and the glossiness when viewed at a 20° angle to the surface 3a of the surface layer 3 can be reduced.

[0046] [Number 5] AB ≤ 11 (5)

[0047] The term "glossiness" used here refers to an indicator of low gloss, and is measured according to the method compliant with JIS Z 8741:1997. For example, "20° glossiness" refers to the glossiness calculated based on the results of measurements taken by a photodetector placed in the direction of the reflection angle when light is incident on the measurement surface (surface 3a of surface layer 3) of laminated sheet 1 at an incident angle of 20°.

[0048] As described above, in the present invention, variations in glossiness on the surface 3a of the surface layer 3 can be suppressed, so even when the viewing angle of the surface 3a of the surface layer 3 is changed, it is possible to suppress changes in the appearance of the surface layer 3.

[0049] Furthermore, in the laminated sheet 1 of the present invention, as described above, irregularities (i.e., valleys 4 and peaks 5) are formed on the surface 3a of the surface layer 3 by irradiating the coating film with excimer light and ultraviolet light. Therefore, the surface layer 3 does not contain particles for forming the valleys 4 and peaks 5. [Examples]

[0050] The present invention will be described below based on examples. However, the present invention is not limited to these examples, and these examples can be modified or altered in accordance with the spirit of the invention; such modifications do not exclude them from the scope of the invention.

[0051] The materials used to create the laminated sheets are listed below. (1) Urethane acrylate - 1:9 functional urethane acrylate (manufactured by Mitsubishi Chemical Corporation, product name: UV-7620EA) (2) Urethane acrylate-2: tetrafunctional urethane acrylate (manufactured by Daicel Ornex Co., Ltd., product name: EBECRYL8606) (3) Urethane acrylate - 3:2 functional urethane acrylate (manufactured by Mitsubishi Chemical Corporation, product name: UV-6630B) (4) Urethane acrylate-4:10 functional urethane acrylate (manufactured by Daicel Ornex Co., Ltd., product name: KRM8452) (5) Urethane acrylate - 5:2 functional urethane acrylate (manufactured by Mitsubishi Chemical Corporation, product name: UV-3300B) (6) Urethane acrylate - 6:6 functional urethane acrylate (manufactured by Mitsubishi Chemical Corporation, product name: UV-7600B) (7) Polyfunctional acrylate: Hexafunctional acrylate (manufactured by Daicel Ornex Co., Ltd., product name: Dipentaerythritol Hexaacrylate (DPHA)) (8) Monofunctional acrylate: Tetrahydrofurfuryl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., product name: Light Acrylate THF-A) (9) Silicone acrylate: (Modified polydimethylsiloxane with acrylic groups) (Manufactured by BYK, trade name: UV3505) (10) Vinyl chloride-vinyl acetate copolymer (manufactured by Nisshin Chemical Industry Co., Ltd., product name: Solvine CL) (11) Glass beads: Average particle size 5 μm (manufactured by Potters Palottini Co., Ltd., product name: EMB-10) (12) Initiator: Alkylphenone-based photopolymerization initiator (manufactured by IGM Resins BV, trade name: Omnirad183)

[0052] (Example 1) <Fabrication of laminated sheets> First, a polyvinyl chloride (PVC) sheet with a thickness of 350 μm was prepared as the base material. Next, the materials shown in Table 1 were blended to prepare the paint of Example 1 having the composition (parts by mass) shown in Table 1. This paint was then applied to the surface of the base material using a bar coater to form a surface layer coating on the surface of the base material.

[0053] Next, the aforementioned coating was dried using a hot air dryer at a temperature of 50°C for 20 seconds.

[0054] Next, using an excimer irradiation device (manufactured by Ushio Inc., product name: 172nm Light Emission Unit, model: SUS1000), Xe was irradiated under a nitrogen atmosphere. 2 The coating was irradiated with excimer light (peak wavelength: 172 nm) using as the discharge gas. The integrated light intensity was 11 mJ / cm². 2 The irradiation intensity is 25 mW / cm². 2 The irradiation was applied in such a manner that it resulted in the following:

[0055] Then, using an ultraviolet irradiation device (a 4kW high-pressure mercury lamp for ultraviolet curing manufactured by iGraphics Co., Ltd. (ECS-401GX)), ultraviolet light (dominant wavelength: 365nm) was irradiated onto the coating film to photo-cure the coating film, thereby forming a surface layer on the surface of the substrate and creating a laminated sheet. The ultraviolet irradiation was performed under conditions of an irradiation distance of 150cm and a lamp movement speed of 7.8m / min (illuminance: 170mW / cm²). 2 ) was performed, and the irradiation dose (cumulative light dose) was set to 200 mJ / cm². 2 That's what I decided.

[0056] Furthermore, Figure 2 shows a laser microscope image illustrating the surface condition of the surface layer. As shown in Figure 2, it can be seen that numerous irregularities are formed on the surface of the surface layer when the coating film, which forms the surface layer, is irradiated with excimer light.

[0057] <Measuring Thickness> Next, the thickness of the surface layer (coating) of the fabricated laminated sheet was measured using a digital microscope (Keyence Corporation, product name: VHX-5000) or a field emission scanning electron microscope (SEM) (Hitachi High-Technologies Corporation, product name: S-4800).

[0058] More specifically, the sheet was cut to expose the cross-section, and five locations with high and low coating heights were selected from the cross-section observed using a digital microscope (magnification: 500x) or a field emission scanning electron microscope (magnification: 1000x). The thickness was measured, and the average value was calculated. This measurement was performed three times, and the average of the coating heights from the three measurements was calculated as the thickness of the surface layer. The results are shown in Table 1.

[0059] <Measurement of maximum valley depth Sv and maximum peak height Sp> Next, the maximum valley depth Sv and maximum peak height Sp on the surface of the surface layer of the produced laminated sheet were measured in accordance with ISO 25178-2:2021 using a shape analysis laser microscope (manufactured by Keyence Corporation, product name: VK-X1050).

[0060] A 661 nm semiconductor laser was used as the laser type; in the surface profile mode (high-speed mode), a 50× standard objective lens was used, under the condition that the measurement pitch was 0.13 μm, and in a measurement range of 1024 pixels × 768 pixels (area of the measurement region (defined region): 276.778 μm × 207.516 μm = 57436 μm 2 ), the maximum valley depth Sv and maximum peak height Sp on the surface of the surface layer were measured. The above measurement was performed at arbitrary positions (3 locations) on the surface of the surface layer of the laminated sheet, the respective average values of the three measurements of maximum valley depth Sv and three measurements of maximum peak height Sp were calculated, and these were taken as the maximum valley depth Sv and maximum peak height Sp on the surface of the surface layer. The value of Sv / (Sv+Sp) was also calculated based on the measured maximum valley depth Sv and maximum peak height Sp. The above results are shown in Table 1.

[0061] <Measurement of glossiness> Next, the 85° glossiness A and 20° glossiness B on the surface of the surface layer of the above-produced laminated sheet were measured in accordance with JIS Z 8741:1997 using a gloss meter (manufactured by Konica Minolta Japan, Inc., product name: Appearance Analyzer Rhopoint IQ-S). The above measurement was performed three times, the average value of the three glossiness measurements was calculated, and this was taken as the surface glossiness of the surface layer. The above results are shown in Table 1.

[0062] (Examples 2 to 5, Comparative Examples 1 to 3) A laminated sheet was produced in the same manner as in Example 1 described above, except that the composition of the coating components was changed to the composition (parts by mass) shown in Table 1.

[0063] Then, in the same manner as in Example 1 described above, the thickness, maximum valley depth Sv and maximum peak height Sp, and glossiness were measured. The results are shown in Tables 1 and 2.

[0064] (Example 6) First, a polyvinyl chloride sheet with a thickness of 90 μm was prepared as the base material, and a transparent polyvinyl chloride sheet with a thickness of 60 μm was prepared as the surface layer.

[0065] Next, a transparent polyvinyl chloride sheet with a thickness of 60 μm, which will serve as the surface layer, was laminated onto a polyvinyl chloride sheet with a thickness of 90 μm, thereby obtaining a polyvinyl chloride sheet having a laminated structure (two-layer structure) comprising a base material and a surface layer provided on the surface of the base material.

[0066] Next, using an embossing roll produced by milling, predetermined irregularities were formed on the surface of the resulting laminated polyvinyl chloride sheet (i.e., the surface on the surface layer side), thereby producing a laminated sheet having a surface layer with irregularities.

[0067] Then, in the same manner as in Example 1 described above, the thickness, maximum valley depth Sv and maximum peak height Sp, and glossiness were measured. The results are shown in Table 1.

[0068] (Comparative Example 4) First, a commercially available decorative sheet (manufactured by Takiron CI Co., Ltd., product name: belbien® WA-227R Berg Cherry, a sheet in which a surface layer containing ultraviolet-curable resin is provided on the surface of a polyvinyl chloride sheet, base material thickness: 150 μm, surface layer thickness: 2 μm) was prepared.

[0069] Then, in the same manner as in Example 1 described above, the maximum valley depth Sv and maximum peak height Sp, as well as the glossiness, were measured. The results are shown in Table 2.

[0070] [Table 1]

[0071] [Table 2]

[0072] As shown in Table 1, in the laminated sheets of Examples 1 to 5, where the maximum valley depth Sv and the maximum peak height Sp, according to ISO 25178-2:2021, satisfy the relationship given by equations (3) to (4) above, the difference between the 85° gloss A and the 20° gloss B of the surface layer (i.e., AB) is 11 or less. This indicates that the balance of the uneven shape on the surface layer is excellent, variations in the gloss of the surface layer can be suppressed, and changes in the appearance of the surface layer can be suppressed even when the viewing angle of the surface layer is changed. [Industrial applicability]

[0073] As described above, the present invention is suitable for laminated sheets. [Explanation of Symbols]

[0074] 1 Laminated sheet 2 Base material 2a Surface of the substrate 3 Surface layer 3a Surface of the surface layer 4. Valleys on the surface of the surface layer 5. Mountains on the surface of the surface layer

Claims

1. Substrate and A surface layer provided on the surface of the substrate and Equipped with, The laminated sheet having valleys and peaks on the surface of the aforementioned surface layer in accordance with ISO 25178-2:2021, A laminated sheet characterized in that the following relationships (1) to (2) hold between the maximum valley depth Sv in accordance with ISO 25178-2:2021 and the maximum peak height Sp in accordance with ISO 25178-2:2021. [Mathematics 1] 1.50μm<Sv<8.50μm (1) [Mathematics 2] 0.40<Sv / (Sv+Sp)<0.65 (2)

2. The laminated sheet according to claim 1, characterized in that the surface layer is an ultraviolet-cured product.

3. The laminated sheet according to claim 1 or 2, characterized in that the surface layer contains a 2- to 10-functional urethane acrylate and a monofunctional acrylate.

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