Laminated sheet

Abstract

The objective is to provide a laminated sheet that offers an excellent balance between scratch resistance and three-dimensional moldability. [Solution] The laminated sheet 1 comprises a base material 2 and a surface layer 3 provided on the surface of the base material 2 and containing tetrafunctional or less urethane acrylate. The laminated sheet is characterized in that the content of tetrafunctional or less urethane acrylate relative to the total surface layer 3 is 85% by mass or more, and when the indentation modulus of the surface layer 3 is Er [GPa] and the indentation hardness of the surface layer 3 is H [GPa], the following relationships (1) to (3) hold true. [Mathematics 1] 0.0194 × Er 2 -0.025 × Er + 0.04 ≥ H (1) [Math 2] 0.4 ≤ Er ≤ 3.1 (2) [Math 3] 0.01 ≤ H ≤ 0.1 (3)

Description

Technical Field

[0001] The present invention relates to a laminated sheet.

Background Art

[0002] Laminated sheets are used for surface decoration to improve design in various applications, including wall materials, moldings, construction materials such as fittings, surface decoration of furniture, decoration sheets for mobility-related applications, and window materials for mobility.

[0003] As such a laminated sheet, for example, a self-healing layer is laminated on one side of a thermoplastic elastomer base material, the self-healing layer is formed by thermally crosslinking urethane resin, silicone resin and isocyanate, and the Martens hardness of the thermoplastic elastomer base material is 0.1 to 10.0 N / mm 2 and the Martens hardness of the self-healing layer is 50 to 300 mN / mm 2 has been proposed. It is described that with such a configuration, a laminated sheet that can ensure good curved surface followability and durability due to self-healing properties can be provided (see, for example, Patent Document 1).

[0004] There is also proposed a laminated sheet having a decorative layer containing a colorant on a base material, and a clear layer containing wet gel method silica particles having an average particle diameter of 5 µm or less measured by a Coulter counter method (AP50 µm) on the decorative layer. It is described that with such a configuration, a laminated sheet that can suitably maintain the color tone of the decorative layer can be provided even when the clear layer contains inorganic particles (see, for example, Patent Document 2).

Prior Art Literature

Patent Literature

[0005]

Patent Document 1

Patent Document 2

[0006] In this context, laminated sheets are required to have scratch resistance and three-dimensional moldability that allows them to be processed into molded products with complex shapes. However, the laminated sheet described in Patent Document 1, while possessing three-dimensional moldability, suffers from poor scratch resistance due to insufficient hardness of the self-healing layer.

[0007] Furthermore, although the laminated sheet described in Patent Document 2 has sufficient hardness, it has the problem of poor three-dimensional moldability because it contains silica particles.

[0008] Therefore, the present invention has been made in view of the above problems, and aims to provide a laminated sheet that has good scratch resistance and three-dimensional moldability, and that has an excellent balance between the conflicting properties of scratch resistance and three-dimensional moldability. [Means for solving the problem]

[0009] 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 and containing a tetrafunctional or less urethane acrylate, wherein the content of the tetrafunctional or less urethane acrylate relative to the total surface layer is 85% by mass or more, and the following relationships (1) to (3) hold when the indentation modulus of the surface layer is Er [GPa] and the indentation hardness of the surface layer is H [GPa].

[0010] [Mathematics 1] 0.0194 × Er 2 -0.025 × Er + 0.04 ≥ H (1)

[0011] [Math 2] 0.4 ≤ Er ≤ 3.1 (2)

[0012] [Math 3] 0.01≦H≦0.1 (3) [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a laminated sheet having good scratch resistance and three-dimensional moldability, and an excellent balance between scratch resistance and three-dimensional moldability. [Brief Description of the Drawings]

[0014] [Figure 1] It is a cross-sectional view showing a laminated sheet according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view showing a modified example of the laminated sheet of the present invention. [Figure 3] It is a figure showing the relationship between indentation elastic modulus Er [GPa] and indentation hardness H [GPa] in the surface layer of the laminated sheet according to the embodiment of the present invention. [Mode for Carrying Out the Invention]

[0015] Hereinafter, the laminated sheet of the present invention will be specifically described. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within a range that does not change the gist of the present invention.

[0016] <Laminated Sheet> As shown in Fig. 1, the laminated sheet 1 of the present invention comprises a base material and a surface layer 3 provided on the surface 2a of the base material 2.

[0017] <Base Material> The base material 2 is made of, for example, a thermoplastic resin sheet, and as this thermoplastic resin sheet, those commonly used for base materials in laminated sheets 1 can be used. Specific examples thereof include polyvinyl chloride (PVC) sheets, glycol-modified polyethylene terephthalate (PETG) sheets, amorphous crystalline polyester resin (APET) sheets, polyolefin sheets (polyethylene sheets, polypropylene sheets, etc.), acrylonitrile butadiene styrene resin (ABS) sheets, polycarbonate sheets, acrylic resin (PMMA) sheets, and the like. Further, examples of the amorphous crystalline polyester resin (APET) sheet used for the base material 2 include recycled polyethylene terephthalate (RPET) sheets made from raw materials such as PET bottles.

[0018] Note that as the thermoplastic resin sheet, resins that facilitate quadratic surface processing and are excellent in three-dimensional moldability are preferable.

[0019] Further, the thermoplastic resin sheet may be a stretched sheet or an unstretched sheet. Additionally, the thermoplastic resin sheet may contain additives such as colorants, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, storage stabilizers, lubricants, and fillers as necessary.

[0020] The thickness of the base material 2 is not particularly limited, but is preferably 0.05 mm to 30 mm, and more preferably 0.25 mm to 10 mm. If the thickness of the base material 2 is 0.05 mm or more, mechanical strength and hiding property can be sufficiently improved. Further, if the thickness of the base material 2 is 30 mm or less, the base material can be continuously produced by extrusion molding.

[0021] <Surface layer> The surface layer 3 is a coating film of a coating material containing urethane acrylate as a main component. This surface layer 3 can be formed by applying the coating material onto the surface 2a of the base material 2 and curing the same, and the surface layer 3 is formed of a cured product of the coating material.

[0022] As the urethane acrylate, those with four or fewer functionalities can be used, such as aliphatic urethane acrylates and aromatic urethane acrylates. In addition, commercially available products such as UV-6640B, UV-7000B, UV-3000B, UV-6630B, EBECRYL8465, EBECRYL4740, EBECRYL270, EBECRYL9260, EBECRYL8402, EBECRYL8405, EBECRYL8701, EBECRYL8409, EBECRYL8804, KRM7735, and EBECRYL8809 (all trade names) can be used. These urethane acrylates may be used individually or in combination of two or more types.

[0023] The weight-average molecular weight (Mw) of the tetrafunctional or less urethane acrylate of the present invention is 1000 or more. A weight-average molecular weight of 1000 or more improves the flexibility of the coating film, enabling three-dimensional molding.

[0024] Furthermore, the term "weight-average molecular weight" used here refers to the weight-average molecular weight in polystyrene terms obtained by gel permeation chromatography (GPC) measurement.

[0025] Furthermore, from the viewpoint of imparting flexibility to the coating film, the content of urethane acrylate relative to the entire surface layer 3 (i.e., 100% by mass of the surface layer) is 85% by mass or more, preferably 88% by mass or more, and more preferably 90% by mass or more.

[0026] Furthermore, the surface layer 3 may contain a polyfunctional (meth)acrylate, specifically a trifunctional or higher acrylate. By using this trifunctional or higher acrylate, it becomes possible to improve the hardness of the coating film.

[0027] In this context, "polyfunctional (meth)acrylate" refers to a monomer of (meth)acrylic acid ester containing two or more (meth)acryloyl groups.

[0028] Examples of acrylates with three or more functionalities include trimethylolpyropane triacrylate, trimethylolpropaneethoxytriacrylate, glycerin propoxytriacrylate, pentaerythritol (tri / tetra)acrylate, pentaerythritol alkoxytetraacrylate, pentaerythritol ethoxytetraacrylate, ditrimethylolpropanetetraacrylate, and dipentaerythritol hexaacrylate. In addition, commercially available products such as TMPTA, DPHA, PETA, PETIA, PETRA, EBECRYL895, EBECRYL160S, EBECRYL40, EBECRYL50, EBECRYL140, EBECRYL1140, EBECRYL896, and EBECRYL1142 (all trade names) can be used. These acrylates with three or more functionalities may be used individually or in combination of two or more types.

[0029] Furthermore, from the viewpoint of imparting hardness to the surface layer 3 and improving the hardness of the coating film, it is preferable that the weight-average molecular weight (Mw) of the trifunctional or more acrylate of the present invention is less than 1000.

[0030] Furthermore, the mixing ratio of tetrafunctional or less urethane acrylate and trifunctional or more 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, but a mass ratio of tetrafunctional or less urethane acrylate to trifunctional or more acrylate in the range of 3:1 to 200:1 is preferred. This is because if the mass ratio of tetrafunctional or less urethane acrylate is too high, the coating may have poor scratch resistance, and if the mass ratio of trifunctional or more acrylate is too high, the coating may have poor three-dimensional moldability.

[0031] Furthermore, the paint may contain other components besides tetrafunctional or less urethane acrylate and trifunctional or more acrylate, to the extent that it does not impair the effects of the invention. Examples of other components include silicone acrylate, photopolymerization initiator, surface modifier, colorant, UV absorber, light stabilizer, antioxidant, antistatic agent, preservative stabilizer, plasticizer, lubricant, filler, etc.

[0032] As photopolymerization initiators, for example, alkylphenone-based, acylphosphine oxide-based, and cationic initiators can be used. Furthermore, as surface modifiers, for example, silicone-modified acrylic polymers can be used.

[0033] <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 one manufactured by a known manufacturing method such as the calendering method or extrusion molding method.

[0034] Next, a coating is applied to the surface 2a of the substrate 2, which is made by adding, for example, the above-mentioned tetrafunctional or less urethane acrylate, trifunctional or more acrylate, and silicone-modified acrylic polymer to a solvent such as methyl ethyl ketone, thereby forming a coating film that will become the surface layer 3 on the surface 2a of the substrate 2.

[0035] Furthermore, the coating method for 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, comma coating method, dip coating method, and flow coating method.

[0036] Then, by irradiating the coating with ultraviolet light (350-450 nm) to cure it, a laminated sheet 1 is manufactured, in which a surface layer 3 is formed on the surface 2a of the substrate 2, as shown in Figure 1.

[0037] Furthermore, the laminated sheet 1 of the present invention has a gloss level of 50 or higher on the surface 3a of the surface layer 3 (i.e., the surface opposite to the substrate 2 side), making it possible to achieve high gloss.

[0038] Furthermore, from the viewpoint of improving glossiness, the glossiness of the surface 3a of the surface layer 3 is preferably 60 or higher, and more preferably 80 or higher.

[0039] Furthermore, the term "glossiness" used here refers to the 60° glossiness measured according to the method compliant with JIS Z 8741:1997. This glossiness is 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 the laminated sheet 1 at an incident angle of 60°.

[0040] Furthermore, in the laminated sheet 1 of the present invention, when the indentation modulus of the surface layer 3 is Er [GPa] and the indentation hardness of the surface layer 3 is H [GPa], the following relationships (4) to (6) hold true. This makes it possible to balance the hardness and flexibility of the coating film forming the surface layer 3, and as a result, it becomes possible to obtain a laminated sheet with an excellent balance between scratch resistance and three-dimensional moldability, which are conflicting properties.

[0041] [Math 4] 0.0194 × Er 2 -0.025 × Er + 0.04 ≥ H (4)

[0042] [Number 5] 0.4 ≤ Er ≤ 3.1 (5)

[0043] [Number 6] 0.01 ≤ H ≤ 0.1 (6)

[0044] In other words, as shown in Figure 3, in region R where the relationship described in (4) to (6) above holds between the indentation modulus Er [GPa] of the surface layer 3 and the indentation hardness H [GPa] of the surface layer 3, it becomes possible to balance the hardness and flexibility of the coating film forming the surface layer 3, as described in the later examples. This makes it possible to obtain a laminated sheet with an excellent balance between the conflicting properties of scratch resistance and three-dimensional moldability.

[0045] The indentation modulus Er and indentation hardness H are measured in accordance with ISO 14577 by the nanoindentation method using a nanoindenter, and are obtained from the load-displacement curve obtained by pressing the indenter indenter into the surface 3a of the surface layer 3 which is the target of measurement (sample).

[0046] More specifically, the indentation modulus Er is calculated using the following equation (7), with respect to the slope S of the tangent to the unloading curve obtained from the load-displacement curve described above, and the contact projection area A between the indenter and the surface layer.

[0047] [Number 7] Compression modulus Er[GPa] = (√π / 2) × (S / √A) (7)

[0048] Furthermore, the indentation hardness H is calculated using the maximum load Pmax obtained from the load-displacement curve described above and the contact projection area A, by the following equation (8).

[0049] [Number 8] Indentation hardness H[GPa] = Pmax / A (8)

[0050] Furthermore, from the viewpoint of balancing scratch resistance and three-dimensional moldability, the indentation modulus Er is preferably 0.4 GPa or more and 3.1 GPa or less, and more preferably 0.8 GPa or more and 2.9 GPa or less.

[0051] Similarly, from the viewpoint of balancing scratch resistance and three-dimensional moldability, the indentation hardness H is preferably 0.01 GPa or more and 0.1 GPa or less, and more preferably 0.02 GPa or more and 0.08 GPa or less.

[0052] Furthermore, in the laminated sheet 1 of the present invention, as described above, it is possible to balance the hardness and flexibility of the coating film forming the surface layer 3, thereby obtaining a good pencil hardness. In addition to being used as a building material, the laminated sheet is also used as a decorative sheet for mobility-related applications, and therefore, a pencil hardness of 2B or higher is preferred for the surface layer 3, with HB or higher being more preferable.

[0053] Furthermore, the term "pencil hardness" used here refers to the pencil hardness (750g load) measured in accordance with JIS K5600-5-4 (1999).

[0054] As described above, the present invention makes it possible to provide a laminated sheet that has an excellent balance between scratch resistance and three-dimensional moldability.

[0055] <Other forms> In the above embodiment, a laminated sheet having a two-layer structure in which the base material and surface layer are laminated in that order was described as an example. However, as shown in Figure 2, for example, an intermediate layer (primer layer) 4 may be provided on the surface 2a of the base material 2 between the base material 2 and the surface layer 3, and the laminated sheet 10 may have a three-layer structure in which the base material, intermediate layer, and surface layer are laminated in that order.

[0056] The intermediate layer 4 is not particularly limited as long as it can improve the adhesion between the substrate 2 and the surface layer 3. For example, a two-component curing primer mainly composed of polyester resin, or a primer mainly composed of acrylic resin and vinyl chloride-vinyl acetate copolymer can be used.

[0057] Furthermore, from the viewpoint of improving the adhesion between the substrate 2 and the surface layer 3, the thickness of the intermediate layer 4 is preferably 0.01 to 100 μm, and more preferably 0.5 to 10 μm. [Examples]

[0058] 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 and altered in accordance with the spirit of the invention; such modifications do not exclude them from the scope of the invention.

[0059] The materials used to create the laminated sheets are listed below. (1) Urethane acrylate - 1:2 functional urethane acrylate (weight-average molecular weight: 5000, manufactured by Mitsubishi Chemical Corporation, product name: UV-6640B) (2) Urethane acrylate-2:2 functional urethane acrylate (weight-average molecular weight: 3500, manufactured by Mitsubishi Chemical Corporation, product name: UV-7000B) (3) Urethane acrylate-3: Trifunctional urethane acrylate (weight-average molecular weight: 1400, manufactured by Daicel Ornex Co., Ltd., product name: EBECRYL8465) (4) Urethane acrylate-4: Trifunctional urethane acrylate (weight-average molecular weight: 1250, manufactured by Daicel Ornex Co., Ltd., product name: EBECRYL4740) (5) Urethane acrylate-5:2 functional urethane acrylate (weight-average molecular weight: 1000, manufactured by Daicel Ornex Co., Ltd., product name: EBECRYL8402) (6) Urethane acrylate-6: tetrafunctional urethane acrylate (weight-average molecular weight: 2700, manufactured by Daicel Ornex Co., Ltd., product name: EBECRYL8405) (7) Urethane acrylate - 7:2 functional urethane acrylate (weight-average molecular weight: 36000, manufactured by Daicel Ornex Co., Ltd., product name: EBECRYL8413) (8) Urethane acrylate-8:2 functional urethane acrylate (weight-average molecular weight: 3000, manufactured by Daicel Ornex Co., Ltd., product name: KRM7735) (9) Polyfunctional (meth)acrylate - 1:3 functional acrylate (acrylic equivalent: 95, weight-average molecular weight: 286, manufactured by Daicel Ornex Co., Ltd., product name: trimethylolpropane triacrylate (TMPTA)) (10) Polyfunctional (meth)acrylate-2: Hexafunctional acrylate (acrylic equivalent: 87), weight-average molecular weight: 520, manufactured by Daicel Ornex Co., Ltd., product name: Dipentaerythritol hexaacrylate (DPHA) (11) Modified acrylate-1:6 functional silicone acrylate (weight-average molecular weight: 1100, manufactured by Daicel Ornex Co., Ltd., product name: EBECRYL1360) (12) Modified acrylate-2:12 functional silicone acrylate (manufactured by Daicel Ornex Co., Ltd., product name: KRM8479) (13) Silicone-modified acrylic polymer (manufactured by BIC Chemie Japan Co., Ltd., product name: SILCLEAN3700)

[0060] (Example 1) <Fabrication of laminated sheets> First, a PVC substrate with a thickness of 250 μm was prepared. 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 substrate using a bar coater to form a surface layer coating on the substrate surface.

[0061] Next, using an ultraviolet irradiation device (a 4kW high-pressure mercury lamp for ultraviolet curing manufactured by iGraphics Co., Ltd. (H04-L41)), ultraviolet light (dominant wavelength: 365nm) was irradiated onto the coating film to photo-cure it, 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 15cm and a lamp movement speed of 0.50m / min, with an irradiation dose of 250mJ / cm². 2 That's what I decided.

[0062] <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).

[0063] More specifically, the sheet was cut to expose the cross-section, and the thickness [μm] of the cross-section was measured using a digital microscope (magnification: 500x) or a field emission scanning electron microscope (magnification: 1000x), and the average value was calculated. The above measurement was performed three times, and the average of the three coating heights was calculated and used as the thickness of the surface layer. The results are shown in Table 1.

[0064] <Measuring pencil hardness> In accordance with JIS K5600-5-4 (1999), the pencil hardness of the surface layer of the prepared laminated sheet was measured using a pencil hardness tester (manufactured by Shinto Kagaku Co., Ltd., product name: HEIDON-14DR) under the conditions of a load of 750g, a speed of 1mm / second, and a pencil (manufactured by Mitsubishi Pencil Co., Ltd., product name: uni) at a 45° angle to the laminated sheet. The pencil hardness was defined as the hardest pencil that did not cause damage to the surface layer when scratched with pencils of each hardness. The results are shown in Table 1.

[0065] <Evaluation of scratch resistance (nail scratch resistance)> Next, the laminated sheet prepared as described above was placed on a glass plate, and the surface layer of the laminated sheet was rubbed five times at a speed of approximately 300 mm / sec with the fingernail of the index finger at an angle of approximately 90° to the surface layer of the laminated sheet (i.e., five different parts of the surface layer of the laminated sheet were rubbed once each). The condition of the surface layer of the laminated sheet was then visually inspected, and the scratch resistance was evaluated based on the following evaluation criteria. The results are shown in Table 1.

[0066] No scratches were found on the surface layer of the laminated sheet: ◎ Depending on the viewing angle, faint scratches can be seen on the surface layer of the laminated sheet: ○ There are faint scratches visible on the surface layer of the laminated sheet, regardless of the viewing angle: △ There are large, clearly recognizable scratches on the surface layer of the laminated sheet: ×

[0067] <Heat stretching treatment and evaluation of heat stretchability> Next, the prepared laminated sheets were subjected to heat stretching. More specifically, strip-shaped test pieces measuring 25 mm x 80 mm were prepared, and a tensile test was conducted by stretching them in the long-side direction at a stretching temperature of 90°C, a tensile speed of 300 mm / min, and a chuck distance of 50 mm. The heat stretching treatment was performed in 10% increments from 10% to 100% until cracks occurred in the test pieces, and the "upper limit of the stretching ratio [%] at which cracks do not occur" was defined as the heat stretching rate [%].

[0068] For example, if no cracks occurred when stretched 60% in the long side direction, but cracks occurred when stretched 70% in the long side direction, then the "upper limit of the stretching ratio [%] at which cracks do not occur" was determined to be 60%, and the heat stretching ratio was set to 60%. Furthermore, a heat stretching ratio of 60% or higher was considered to indicate good heat stretchability. The results are shown in Table 1.

[0069] <Evaluation of three-dimensional moldability> Next, an MDF substrate (a substrate with a roughly rectangular prism shape, 100 mm wide, 150 mm long, and 15 mm thick, with all corners chamfered to a radius of 2 mm) was prepared. The laminated sheet prepared as described above was placed on the MDF substrate, and using a vacuum forming machine (manufactured by Seibu Co., Ltd., product name: STN-40-600-800) at a heating temperature of 110°C, the top surface and four sides of the MDF substrate (a total of 5 surfaces) were covered with the laminated sheet. Vacuum forming was performed on the top surface and four sides of the MDF substrate (a total of 5 surfaces) so that the laminated sheet conformed to the MDF substrate, and the laminated sheet was made to adhere tightly to the top surface and four sides of the MDF substrate (a total of 5 surfaces). The condition of the surface layer of the laminated sheet covering the top surface, sides, and corners of the MDF substrate was visually inspected with the naked eye and using a 10x magnifying glass, and the three-dimensional moldability was evaluated based on the following evaluation criteria. The results are shown in Table 1.

[0070] The laminated sheet is molded along the MDF substrate, and there are no cracks or changes in gloss on the surface layer of the laminated sheet: ○ There are visible cracks in the surface layer of the laminated sheet: ×

[0071] <Measurement of indentation modulus Er and indentation hardness H> In accordance with ISO 14577, the indentation modulus Er and indentation hardness H of the surface layer of the fabricated laminated sheet were measured using the nanoindentation method with a nanoindenter (Bruker Corporation, product name: TS 77) under the following measurement conditions. More specifically, a load-displacement curve was obtained by pressing the indenter of the nanoindenter into the surface layer of the fabricated laminated sheet. Then, the indentation modulus Er and indentation hardness H of the surface layer were calculated from the obtained load-displacement curve based on equations (7) to (8) described above. Furthermore, the value of the left side of equation (4) described above was calculated using the calculated value of the indentation modulus Er. The results are shown in Table 1.

[0072] (Measurement conditions) Measurement method: Quasi-static nanoindentation Indenter used: Berkovich indenter (triangular pyramidal diamond indenter, ridge angle 115°) Measurement temperature: 23℃ Indentation speed: 50nm / sec Maximum load holding time: 5sec Unloading speed: 50nm / sec Indentation depth: 200nm

[0073] <Measurement of glossiness> The 60° gloss of the surface layer of the fabricated laminated sheet was measured using a gloss meter (Horiba, Ltd., product name: Gloss Checker IG-320) in accordance with JIS Z 8741:1997. This measurement was performed three times, and the average of the three gloss values ​​was calculated to determine the gloss of the surface layer. The results are shown in Table 1.

[0074] (Examples 2-10, Comparative Examples 1-12) The laminated sheet was prepared in the same manner as in Example 1 described above, except that the composition of the paint components was changed to the composition (parts by mass) shown in Table 1.

[0075] Then, in the same manner as in Example 1 described above, thickness was measured, pencil hardness was measured, scratch resistance (nail scratch resistance) was evaluated, heat stretching treatment was performed and heat stretchability was evaluated, three-dimensional moldability was evaluated, the indentation modulus Er and indentation hardness H were measured, and glossiness was measured. The results are shown in Tables 1 to 3.

[0076] [Table 1]

[0077] [Table 2]

[0078] [Table 3]

[0079] As shown in Table 1, in the laminated sheets of Examples 1 to 10, the relationships (4) to (6) above hold between the indentation modulus Er [GPa] of the surface layer 3 and the indentation hardness H [GPa] of the surface layer 3. Therefore, it can be seen that the sheet exhibits good scratch resistance and three-dimensional moldability, and that a laminated sheet with an excellent balance between the conflicting properties of scratch resistance and three-dimensional moldability can be obtained. [Industrial applicability]

[0080] As described above, the present invention is suitable for laminated sheets. [Explanation of symbols]

[0081] 1 Laminated sheet 2 Base material 2a Surface of the substrate 3 Surface layer 3a Surface of the surface layer 4. Middle Class 10 Laminated Sheets

Claims

1. Substrate and The substrate is provided with a surface layer containing a tetrafunctional or less urethane acrylate, The content of the tetrafunctional or less urethane acrylate relative to the entire surface layer is 85% by mass or more. A laminated sheet characterized in that, when the indentation modulus of the surface layer is Er [GPa] and the indentation hardness of the surface layer is H [GPa], the following relationships (1) to (3) hold true. [Mathematics 1] 0.0194×Er ２ -0.025×Er+0.04≧H (1) [Mathematics 2] 0.4 ≤ Er ≤ 3.1 (2) [Mathematics 3] 0.01 ≤ H ≤ 0.1 (3)

2. The laminated sheet according to claim 1, characterized in that the pencil hardness (750g load) of the surface layer, measured in accordance with JIS K5600-5-4 (1999), is 2B or higher.

3. The laminated sheet according to claim 1 or 2, characterized in that the glossiness of the surface layer is 50 or higher.

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