Decorative sheet, decorative member, moving body, building structure, and method for manufacturing decorative member

Abstract

A decorative sheet (20) is provided with a substrate layer (21) and a decorative layer (23). The decorative layer (23) is formed on one surface (21B or 21A) of the substrate layer (21). When subjected to a tensile property test performed under the conditions of a test speed of 300 mm / min and an ambient temperature of 23 °C, the decorative sheet (20) satisfies the following expressions of y>30, y>-0.85x+170, and 0<x<200, where the strength at break and the elongation at break are x(N) and y(%), respectively.

Description

Decorative sheet, decorative member, mobile body, architectural structure, and method for manufacturing decorative member

[0001] The present disclosure relates to a decorative sheet, a decorative member, a moving body, an architectural structure, and a method for manufacturing a decorative member.

[0002] Painting is applied to various products, such as building materials, home appliances, and automobile bodies, to impart functionality such as design and durability to them. For example, as described in JP2004-271052A, the process of painting the body of a mobile object such as an automobile includes a coating step of applying paint to the body and a drying step of placing the painted body in a drying oven to bake the paint onto the body. By painting the body, the mobile object is decorated and exhibits an excellent appearance.

[0003] However, there are concerns about the environmental impact of volatile organic compounds in paint and carbon dioxide emitted during the drying process. In recent years, growing environmental concerns have led to demand for more environmentally friendly manufacturing methods for vehicles.

[0004] An embodiment of the present disclosure aims to reduce the environmental impact during the production of decorative members.

[0005] The decorative sheet of the present disclosure comprises: a base layer; and a decorative layer formed on one surface of the base layer, and in a tensile property test conducted at a test speed of 300 mm / min and an ambient temperature of 23°C, the strength at break and the elongation at break satisfy the following equations: y>30 y>-0.85x+170, 0<x<200, where x (N) and y (%) represent the strength at break and the elongation at break, respectively.

[0006] According to an embodiment of the present disclosure, it is possible to reduce the environmental impact during the production of a decorative member.

[0007] FIG. 1 is a perspective view of a moving body. FIG. 2 is a cross-sectional view of a decorative member. FIG. 3 is a diagram illustrating a manufacturing method of a decorative member. FIG. 4 is a diagram illustrating a manufacturing method of a decorative member. FIG. 5 is a cross-sectional view illustrating the layer structure of a decorative sheet. FIG. 6 is a perspective view of a mold illustrating a first bending test. FIG. 7 is a diagram illustrating a cross-section of a laminate plate press-formed using the mold shown in FIG. 6. FIG. 8 is a diagram illustrating the strength against breakage and elongation at breakage of the decorative sheets of Examples 1 to 22 and Comparative Examples 1 to 8.

[0008] One embodiment of the present disclosure relates to the following <1> to <11>.

[0009] <1> A decorative sheet comprising: a base layer; and a decorative layer formed on one surface of the base layer, wherein, in a tensile property test conducted at a test speed of 300 mm / min and an ambient temperature of 23°C, the following formulas are satisfied: y>30, y>-0.85x+170, 0<x<200, where x (N) is the strength at break and y (%) is the elongation at break, respectively.

[0010] <2> The decorative sheet according to <1>, which satisfies the following condition: 30<y<425.

[0011] <3> The decorative sheet according to <1> or <2>, wherein the base layer contains polyethylene terephthalate or thermoplastic polyurethane.

[0012] <4> The decorative sheet according to any one of <1> to <3>, further comprising a surface protection layer that forms a front side of the decorative sheet.

[0013] <5> The decorative sheet according to <4>, wherein the surface protective layer contains polycarbonate (meth)acrylate and / or urethane (meth)acrylate.

[0014] <6> The decorative sheet according to any one of <1> to <5>, further comprising a backer layer that forms a back surface of the decorative sheet or that is disposed between the back surface of the decorative sheet and the decorative layer.

[0015] <7> The decorative sheet according to <6>, wherein the backer layer contains polyvinyl chloride.

[0016] <8> A decorative member comprising the decorative sheet according to any one of <1> to <7>.

[0017] <9> A moving body including the decorative member according to <8>.

[0018] <10> An architectural structure comprising the decorative member according to <8>.

[0019] <11> A method for manufacturing a moving body, comprising: a step of preparing a decorative sheet according to any one of <1> to <7>; a step of adhering the decorative sheet to a steel plate; and a step of bending the steel plate with the decorative sheet adhered thereto at a temperature of −5° C. or higher and 40° C. or lower.

[0020] In the drawings accompanying this specification, the scale and the aspect ratios of the dimensions are appropriately changed and exaggerated from those of the actual objects for the sake of convenience in illustration and understanding.

[0021] In this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely on the basis of differences in name. For example, a "decorative sheet" cannot be distinguished from a member called a decorative film or a decorative plate solely on the basis of differences in name.

[0022] In this specification, the direction perpendicular to a sheet-like (film-like, plate-like) member refers to a direction parallel to a perpendicular or normal line to the plate surface of the target sheet-like (film-like, plate-like) member. The term "sheet surface (film surface, plate surface)" refers to a surface that coincides with the target sheet-like (film-like, plate-like) member when the target sheet-like (film-like, plate-like) member is viewed overall and globally.

[0023] In this specification, multiple upper limit candidate values ​​and multiple lower limit candidate values ​​for a numerical range may be described in separate sentences. In this description, the numerical range may be constructed by combining any one upper limit candidate value and any one lower limit candidate value. As an example, consider the description, "Parameter B may be A1 or more, A2 or more, or A3 or more. Parameter B may be A4 or less, A5 or less, or A6 or less." In this example, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

[0024] An embodiment of the present disclosure will be described with reference to the drawings. A mobile body is shown as an embodiment of the present disclosure, but the present disclosure is not limited thereto and may also be applied to architectural structures (e.g., doors, bathrooms, interior walls, exterior walls), home appliances, etc. FIG. 1 shows a mobile body 1 according to an embodiment of the present disclosure. The mobile body 1 is a movable device or equipment. In the example shown in FIG. 1, the mobile body 1 is an automobile. The mobile body 1 may also be a motorcycle, bicycle, tricycle, train, airplane, ship, snowmobile, industrial robot, drone, etc. The automobile may also be a truck, bus, taxi, ambulance, fire engine, police vehicle, construction vehicle, etc.

[0025] <<Decorative Member>> The moving body 1 has a decorative member 10. In the example shown in Fig. 1 , an automobile has the decorative member 10 as a part of its exterior body. The part of the exterior body of the automobile is, for example, at least one of a hood, a roof, a fender, a bumper, a mirror, a door, a pillar, a sill, and a trunk lid. In the example shown, the automobile has the hood as the decorative member 10. The moving body 1 may have multiple decorative members 10.

[0026] The decorative member 10 may include a flat portion on its surface. The decorative member 10 may include a curved portion on its surface. Fig. 2 shows a cross-sectional view of the decorative member 10. In Fig. 2, the decorative member 10 has been bent. In the illustrated example, the central portion C of the decorative member 10 is formed with irregularities. In addition, the edge portion E of the decorative member 10 is folded back (so-called hemming).

[0027] As shown in Fig. 2, the decorative member 10 includes an adherend 11, a decorative sheet 20, and an adhesive layer 15 between the adherend 11 and the decorative sheet 20. The decorative sheet 20 displays a design. By covering the adherend 11 with the decorative sheet 20, the decorative member 10 displays the design. This gives the decorative member 10 an excellent appearance. Furthermore, by decorating the adherend 11 by covering it with the decorative sheet 20, the amount of volatile organic compounds used and carbon dioxide emissions can be effectively reduced compared to decorating the adherend 11 by painting.

[0028] The adherend 11 is formed of a steel plate, more specifically, a cold-rolled steel plate (SPCC). Steel plates are widely used as materials for components constituting the bodies of mobile objects (particularly automobiles). The cold-rolled steel plate (SPCC) may be subjected to a rust prevention treatment such as hot-dip galvanizing. The adherend 11 is bent.

[0029] The adherend 11 includes a first surface 11A and a second surface 11B. The first surface 11A and the second surface 11B are a pair of main surfaces of the adherend 11. The second surface 11B is the surface opposite to the first surface 11A. The second surface 11B of the adherend 11 forms the back side of the decorative member 10. The thickness of the adherend 11 is not particularly limited, but may be, for example, 0.4 mm or more and 0.8 mm or less.

[0030] The decorative sheet 20 covers the first surface 11A of the adherend 11. The decorative sheet 20 is bent together with the adherend 11.

[0031] The decorative sheet 20 includes a first surface 20A and a second surface 20B. The first surface 20A and the second surface 20B are a pair of main surfaces of the decorative sheet 20. The second surface 20B is the surface opposite to the first surface 20A. The first surface 20A and the second surface 20B form the front and back surfaces of the decorative sheet 20, respectively. The first surface 20A of the decorative sheet 20 forms the front surface of the decorative member 10. The second surface 20B of the decorative sheet 20 faces the first surface 11A of the adherend 11. In the illustrated example, the decorative sheet 20 is attached to the adherend 11 by an adhesive layer 15. The configuration of the decorative sheet 20 will be described in detail later.

[0032] From the viewpoint of stably displaying the design, a lower limit may be set for the thickness of the decorative sheet 20. The thickness of the decorative sheet 20 may be 30 μm or more, 38 μm or more, 55 μm or more, or 60 μm or more.

[0033] From the viewpoint of facilitating bending, an upper limit may be set for the thickness of the decorative sheet 20. The thickness of the decorative sheet 20 may be 300 μm or less, 265 μm or less, 200 μm or less, 165 μm or less, 130 μm or less, or 105 μm or less.

[0034] The thickness of the decorative sheet 20 and the thickness of the components of the decorative sheet 20 are determined by observing a cross-sectional image of the decorative sheet 20. A scanning transmission electron microscope (STEM) is used to observe the cross-sectional image of the decorative sheet 20. The thickness of the decorative sheet 20 and the thickness of the components of the decorative sheet 20 are determined as the arithmetic mean of five measured values ​​at five different locations.

[0035] The adhesive layer 15 is in the form of a thin film. The adhesive layer 15 exhibits adhesiveness at temperatures of -5°C or higher and 40°C or lower. -5°C or higher and 40°C or lower are the environmental temperatures during normal bending of steel plates. The adhesive layer 15 may exhibit adhesiveness at temperatures of -40°C or higher and 95°C or lower. -40°C or higher and 95°C or lower are the environmental temperatures in which the moving body 1 may be placed.

[0036] The material forming the adhesive layer 15 is not particularly limited, but the adhesive layer 15 may contain a resin. The adhesive layer 15 may contain a thermoplastic resin or a thermosetting resin. A thermoplastic resin is a resin that softens when heated. A thermosetting resin is a resin that hardens when heated. The adhesive layer 15 may contain a polyurethane resin, a polyester urethane resin, a polyester, a polyolefin, a polyamide, polymethyl (meth)acrylate, or an ethylene-vinyl acetate copolymer. The thickness of the adhesive layer 15 is not particularly limited, but may be, for example, 10 μm or more and 100 μm or less.

[0037] For example, "Mold Fit 50" manufactured by Nichiei Shinka Co., Ltd. may be used as the adhesive layer 15. Alternatively, an adhesive composition containing a base agent available from Daido Kasei Kogyo Co., Ltd. under the product name "Dicalac (registered trademark) 5021" and a curing agent available from Tosoh Corporation under the product name "Coronate HX" may be used as the adhesive layer 15.

[0038] An adhesive layer that has a bond strength of 7 N / 25 mm or more or that breaks (breaks material) when subjected to the following method can be suitably used as the adhesive layer 15. Furthermore, an adhesive layer with an adhesive strength of 10 N / 25 mm or more is more suitable.

[0039] <Measurement Method> Measurements can be made in accordance with JIS Z0237:2009 (Test Methods for Pressure-Sensitive Adhesive Tapes and Sheets) and Method 1 of the Test Method for Adhesive Strength (a test method in which the tape and sheet are peeled off at 180° from a stainless steel test plate at a temperature of 23°C and a humidity of 50%). However, the standing time after lamination is set at room temperature (23°C), a humidity of 50%, and 24 hours. If the adhesiveness does not meet the above requirements, it may be heated to improve the adhesiveness so that it falls within the above index. The heating conditions may be 40°C, 60°C, 80°C, or 95°C.

[0040] <<Method of Manufacturing Decorative Molded Member>> In the illustrated example, the decorative member 10 is manufactured as follows: First, an adhesive layer 15 is formed on the first surface 11A of the adherend 11 or the second surface 20B of the decorative sheet 20. The adhesive layer 15 may be formed by applying the above-described material for the adhesive layer 15 to the first surface 11A or the second surface 20B.

[0041] Next, the decorative sheet 20 is adhered to the adherend 11. Specifically, the decorative sheet 20 is laminated on the adherend 11 so that the first surface 11A of the adherend 11 and the second surface 20B of the decorative sheet 20 face each other via the adhesive layer 15. The step of adhering the decorative sheet 20 to the adherend 11 may be performed at the ambient temperature (room temperature) used in normal steel plate bending, or at a temperature higher than the ambient temperature. In other words, in the step of adhering the decorative sheet 20 to the adherend 11, the decorative sheet 20 may or may not be heated. The step of adhering the decorative sheet 20 to the adherend 11 may be performed at a temperature between −5° C. and 250° C., for example. Furthermore, in the step of adhering the decorative sheet 20 to the adherend 11, the decorative sheet 20 does not need to be stretched. In this way, the laminate plate 12 shown in FIG. 3 is produced. In FIG. 3, the adhesive layer 15 is not shown.

[0042] Next, the laminate sheet 12 is bent and formed into the shape of the hood shown in FIG. 1 . In other words, the adherend 11 and the decorative sheet 20 are simultaneously formed into the shape of the hood. In the illustrated example, the laminate sheet 12 is formed into the shape shown in FIGS. 1 and 2 by performing a first bending process and a second bending process. In the first bending process, a press die 30 is first prepared. Next, the laminate sheet 12 is pressed in the press die 30 to form the portion other than its edge E. More specifically, as shown in FIG. 3 , the laminate sheet 12 is placed between a male die 31 and a female die 32 of the press die 30, and the male die 31 and the female die 32 are brought close to each other to deform the laminate sheet 12 as shown in FIG. 4 . In the second bending process, a hemming process is performed on the edge E of the laminate sheet 12. In the illustrated example, the edge E of the pressed laminate plate 12 shown in Fig. 4 is folded back using a known hemming device, thereby producing the decorative member 10 shown in Fig. 1 .

[0043] The first bending step may be performed in a state where the first surface 20A of the decorative sheet 20 is covered with a protective film. The protective film may be made of polyethylene terephthalate (PET) or the like.

[0044] In this embodiment, the bending of the laminate plate 12 may be performed at the environmental temperature (room temperature) used when bending steel plates. In other words, the laminate plate 12 or the decorative sheet 20 does not need to be heated during the bending process. By performing the bending process without heating, it is possible to effectively reduce carbon dioxide emissions during the manufacturing process of the decorative member 10. As described above, the environmental temperature used when bending steel plates is between -5°C and 40°C.

[0045] The molding of the laminate plate 12 involves the molding of the decorative sheet 20 included in the laminate plate 12. If the molding causes any abnormalities in the appearance of the decorative sheet 20, the appearance of the decorative member 10 will be impaired. The abnormalities in the appearance of the decorative sheet 20 include whitening of the decorative sheet 20, the formation of cracks in the decorative sheet 20, and the fracture (tear) of the decorative sheet 20. Whitening of the decorative sheet 20 is thought to be caused by the formation of minute cracks in one or more layers constituting the decorative sheet 20. These abnormalities in appearance occur when the decorative sheet 20, to which tensile stress is applied during molding, is unable to sufficiently stretch. Furthermore, even if the decorative sheet 20 is sufficiently stretched during molding, if it shrinks due to the residual stress after stretching, the decorative sheet 20 will not be able to maintain its adhesion to the adherend 11, and a portion of it will peel off and float away from the adherend 11. Hereinafter, this problem will also be referred to as the "floating problem" of the decorative sheet. In this case, the appearance of the decorative member 10 is also impaired.

[0046] The present inventors conducted extensive research into the above-mentioned problems of appearance abnormalities and lifting of the decorative sheet, and have discovered the following. That is, when the following conditions are satisfied: · x is the strength (N) of the decorative sheet against breakage, and · y is the elongation (%) of the decorative sheet at break, · y > 30 ... (1) · y > -0.85x + 170 ... (2) · 0 < x < 200 ... (3) The problems of appearance abnormalities and lifting of the decorative sheet are suppressed. When conditions (1) and (2) are satisfied, the risk of the above-mentioned appearance abnormalities occurring in the decorative sheet is suppressed, even when the decorative sheet is bent at a large bending angle and a large tensile stress is applied to the decorative sheet. Furthermore, when condition (3) is satisfied, the problem of lifting of the decorative sheet is suppressed. This is because when condition (3) is satisfied, the residual stress in the stretched decorative sheet is low, and the risk of the decorative sheet shrinking after bending is suppressed. In other words, if x is 200 or more, the deformation resistance of the decorative sheet is too high, and the decorative sheet stretched during bending is likely to shrink and peel off from the adherend a short time after bending. From the viewpoint of stably suppressing abnormal appearance of the decorative sheet due to bending, a lower limit may be set for x, i.e., the strength against breakage. In the decorative sheet, x may be 25 N or more, or 30 N or more.

[0047] Furthermore, in consideration of the manufacturing process of the decorative sheet, y<425 (4) may be satisfied. This is because a decorative sheet with a large elongation at break is inherently elongate, and its base layer also tends to be elongate easily, making such a base layer difficult to handle in the manufacturing process of the decorative sheet. From the same perspective, the elongation at break of the decorative sheet may be 300(%) or less.

[0048] In addition to the above-mentioned condition (2), the decorative sheet may also satisfy the following condition (5). That is, the decorative sheet may also satisfy the conditions (1), (2), (3), and (5): y>-0.85x+200 ... (5) When conditions (1) and (5) are satisfied, even if the decorative sheet is bent at a large bending angle and a large tensile stress is applied to the decorative sheet, the risk of the above-mentioned appearance abnormalities occurring in the decorative sheet can be stably suppressed.

[0049] In the decorative sheet, condition (6) may be satisfied when x, i.e., the strength against breakage, is 100 N or less, and condition (7) may be satisfied when x exceeds 100 N. In the decorative sheet, conditions (1), (2), (3), (6), and (7) may be satisfied. In the decorative sheet, conditions (1), (2), (3), (5), (6), and (7) may be satisfied. 30<y<800 (6) 30<y<250 (7) By satisfying condition (6), even if the strength against breakage is relatively low, the risk of the above-mentioned appearance abnormalities occurring during bending due to relatively large elongation can be stably suppressed. Furthermore, by satisfying condition (7), the use of a base layer that is difficult to handle in the manufacturing process of the decorative sheet can be avoided when the strength against breakage is relatively high.

[0050] In this specification, the strength against break of a decorative sheet is defined as "tensile breaking stress of decorative sheet × thickness (mm) of decorative sheet × 10 (mm)." In other words, in this specification, the strength against break of a decorative sheet is determined by cutting a 10 mm wide test piece from the decorative sheet, measuring the tensile breaking stress of the test piece, and multiplying the measurement result by the thickness and width (10 mm) of the test piece. In addition, in this specification, the elongation at break of a decorative sheet means the nominal tensile breaking strain (εtb defined in 3.8.1 of JIS K 7161-1:2014) (unit: %) measured in accordance with JIS K 7161-1:2014. Here, the tensile breaking stress is the tensile breaking stress (σb defined in 3.6.4 of JIS K 7161-1:2014) (unit: MPa) measured in accordance with JIS K 7161-1:2014, expressed as N / mm ２ The test conditions for determining the tensile breaking stress and nominal tensile breaking strain are in accordance with JIS K 7127:1999. The type of test specimen is type 2. The width (b) of the test specimen is 10 mm, and the total length (l ３ The initial distance (L) between the chucks is 100 mm. The thickness of the decorative sheet is measured by the measurement method (Method A) in accordance with JIS K 7130:1999.

[0051] <<Decorative Sheet>> Next, the decorative sheet 20 will be described in detail with reference to Fig. 5 . The decorative sheet 20 includes a base layer 21 and a decorative layer 23. In the example shown in Fig. 5 , the decorative sheet 20 further includes a surface protective layer 24, a bonding layer 25, and a backer layer 26. In this example, the surface protective layer 24, the base layer 21, the decorative layer 23, the bonding layer 25, and the backer layer 26 are stacked in this order in the direction from the first surface 20A to the second surface 20B. Therefore, in the example shown in Fig. 3 , the surface protective layer 24 forms the first surface (front side surface) 20A of the decorative sheet 20. The backer layer 26 forms the second surface (rear side surface) 20B of the decorative sheet 20.

[0052] <Surface Protective Layer> The surface protective layer 24 protects the other layers of the decorative sheet 20. The surface protective layer 24 has various functions, such as scratch resistance, abrasion resistance, weather resistance, and chemical resistance. The surface protective layer 24 also has the ductility required for forming the decorative member 10.

[0053] The surface protection layer 24 is in the form of a thin film. The thickness of the surface protection layer 24 may be, for example, 0.1 μm or more, 0.5 μm or more, 20 μm or less, or 10 μm or less.

[0054] The surface protective layer 24 is transparent. In this specification, "transparent" means that the visible light transmittance is 40% or more, 70% or more, or 80% or more. In this specification, the visible light transmittance is specified as the average value of the light transmittance at each wavelength when measured in 1 nm increments within a wavelength range of 380 nm to 780 nm using a spectrophotometer (Shimadzu Corporation's "UV-3600i Plus," compliant with JIS K0115). When no particular transmission direction is specified, the angle of incidence when measuring the visible light transmittance is set to 0°. The angle of incidence is the angle between the normal to the incident surface and the traveling direction of the incident light, and is a value less than 90°.

[0055] The surface protective layer 24 may contain a cured resin. The cured resin is a cured product of a curable resin composition. The curable resin composition may be a thermosetting resin composition. The curable resin composition may be an ionizing radiation curable resin composition. The curable resin composition may be an ultraviolet curable resin composition. The curable resin composition may be an electron beam curable resin composition. The surface protective layer 24 may contain a cured product of a thermosetting resin composition and a cured product of an ionizing radiation curable resin composition. The cured product of the curable resin composition can improve the scratch resistance of the first surface 20A of the decorative sheet 20. The ionizing radiation curable resin composition is particularly useful from the viewpoint of improving scratch resistance. The ionizing radiation curable resin composition may include an ultraviolet curable resin composition. The ionizing radiation curable resin composition may include an electron beam curable resin composition.

[0056] The thermosetting resin composition contains a thermosetting compound. The thermosetting compound is a resin that hardens when heated. The thermosetting compound is not particularly limited. Examples of thermosetting compounds include phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, melamine-urea co-condensation resins, and silicone resins. The thermosetting resin composition may contain one or more of these thermosetting compounds. The thermosetting resin composition may contain a curing agent. The curing agent promotes the curing of the thermosetting compound. The curing agent may contain an isocyanate compound. The isocyanate compound is a compound containing an isocyanate group. The isocyanate compound may be a polyisocyanate containing multiple isocyanate groups.

[0057] The ionizing radiation-curable resin composition contains a compound having an ionizing radiation-curable functional group. Hereinafter, the compound having an ionizing radiation-curable functional group is also referred to as an "ionizing radiation-curable compound." Examples of the ionizing radiation-curable functional group include ethylenically unsaturated bond groups such as (meth)acryloyl groups, vinyl groups, and allyl groups, as well as epoxy groups and oxetanyl groups.

[0058] The material forming the surface protective layer 24 may be the material for the surface protective layer described in Japanese Patent No. 5476903. The ionizing radiation curable resin forming the surface protective layer 24 may be, for example, a mixture of polycarbonate (meth)acrylate and a polyfunctional (meth)acrylate. In this case, from the viewpoint of improving scratch resistance and moldability, the mass ratio of the polycarbonate (meth)acrylate to the polyfunctional (meth)acrylate is preferably 95:5 to 80:20.

[0059] When an ultraviolet-curable resin composition is used as the ionizing radiation-curable resin composition, it is desirable to add about 0.1 to 5 parts by mass of a photopolymerization initiator per 100 parts by mass of the ultraviolet-curable resin. The photopolymerization initiator is not particularly limited, and known initiators can be used. The photopolymerization initiator may be, for example, the photopolymerization initiator described in Japanese Patent No. 5,476,903. Furthermore, the photosensitizer may be, for example, the photosensitizer described in Japanese Patent No. 5,476,903.

[0060] The ionizing radiation curable resin composition may be applied by a known method such as gravure coating, bar coating, roll coating, reverse roll coating, or comma coating, preferably by gravure coating.

[0061] The ionizing radiation curable resin composition is irradiated with ionizing radiation such as electron beams or ultraviolet rays. The ionizing radiation curable resin composition is cured by irradiation with ionizing radiation. The surface protective layer 24 may be formed by curing the ionizing radiation curable resin composition.

[0062] When an electron beam is used to form the surface protective layer 24, the acceleration voltage can be appropriately selected depending on the type of electron beam curable resin and the thickness of the surface protective layer 24. For example, the acceleration voltage of the electron beam may be 70 kV or more, 150 kV or more, 165 kV or more, or 300 kV or more.

[0063] In electron beam irradiation, the higher the acceleration voltage, the greater the penetration ability. When a resin that is easily deteriorated by electron beam irradiation is used under the surface protective layer 24, the acceleration voltage is selected so that the penetration depth of the electron beam is substantially equal to the thickness of the surface protective layer 24. This makes it possible to prevent excess electron beam irradiation of layers located under the surface protective layer 24, thereby minimizing deterioration of each layer due to excess electron beams.

[0064] The electron beam irradiation dose is preferably an amount at which the crosslink density of the surface protective layer 24 is saturated. The electron beam irradiation dose may be 5 kGy or more (0.5 Mrad or more), or 10 kGy or more (1 Mrad or more). The electron beam irradiation dose may be 300 kGy or less (30 Mrad or less), or 50 kGy or less (5 Mrad or less).

[0065] <Substrate Layer> The substrate layer 21 supports other layers included in the decorative sheet 20, such as the decorative layer 23, the surface protective layer 24, and the bonding layer 25. The substrate layer 21 is in the form of a film. The substrate layer 21 includes a first surface 21A and a second surface 21B. The first surface 21A and the second surface 21B are a pair of main surfaces of the substrate layer 21. The second surface 21B is the surface opposite to the first surface 21A. The thickness of the substrate layer 21 may be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. The thickness of the substrate layer 21 may be 200 μm or less, 180 μm or less, 150 μm or less, or 120 μm or less. The substrate layer 21 may be transparent. In this case, the layer on the second surface 21B side (the decorative layer 23 in the illustrated example) can be observed through the base material layer 21.

[0066] There are no particular limitations on the material of the base layer 21. The base layer 21 may contain a resin. Resin is preferable in that it is lightweight and easy to manufacture.

[0067] The resin used for the base layer 21 may be an olefin-based resin such as polyethylene (low density, medium density, or high density), polypropylene (PP), polymethylpentene, or polybutene. The resin used for the base layer 21 may be a polyolefin-containing resin such as an ethylene-vinyl acetate copolymer or an ethylene-acrylic acid copolymer. The resin used for the base layer 21 may be a vinyl-based resin such as polyvinyl chloride (PVC), polyvinylidene chloride, polyvinyl alcohol, an ethylene-vinyl acetate copolymer, or an ethylene-vinyl alcohol copolymer. The resin used for the base layer 21 may be a thermoplastic resin such as polyester, acrylonitrile-butadiene-styrene (ABS) resin, or polyvinyl chloride (PVC). The resin used for the base layer 21 may be an ester-based resin such as polyethylene terephthalate (PET), polyethylene naphthalate, or polybutylene terephthalate (PBT). The resin used for the base layer 21 may be a urethane-based resin. The resin used for the base layer 21 may be an acrylic resin such as polymethyl(meth)acrylate or polyethyl(meth)acrylate. The resin used for the base layer 21 may be a styrene resin such as polystyrene, a polyamide resin such as nylon 6 or nylon 66, or a cellulose resin such as triacetyl cellulose. Further examples of the resin used for the base layer 21 include resins such as polycarbonate, polyimide resins, and cycloolefin resins obtained from cycloolefins such as norbornene and dicyclopentadiene.

[0068] The resin used for the base layer 21 may be a polyethylene-based resin. The polyethylene-based resin used for the base layer 21 may be a homopolymer of ethylene, i.e., polyethylene, or may be a copolymer of ethylene and another comonomer copolymerizable with ethylene (for example, an α-olefin such as propylene, 1-butene, 1-hexene, or 1-octene, vinyl acetate, or vinyl alcohol). Examples of polyethylene include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), and low-density polyethylene (LDPE), as well as linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), ultra-high molecular weight polyethylene (UHMWPE), and cross-linked polyethylene (PEX).

[0069] The resin used for the base layer 21 may be a polypropylene resin. The polypropylene-based resin used for the base layer 21 may be a homopolymer of propylene, i.e., polypropylene, or a copolymer of propylene and another comonomer copolymerizable with propylene (for example, an α-olefin such as ethylene, 1-butene, 1-hexene, or 1-octene; vinyl acetate, vinyl alcohol, or the like).

[0070] The substrate layer 21 may contain only one of the above-mentioned resins, or may contain two or more of the above-mentioned resins.

[0071] Considering the above-mentioned conditions (1) to (3), it is preferable that the resin forming the base layer 21 is, for example, polyethylene terephthalate (PET), thermoplastic polyurethane (TPU), or polyvinyl chloride (PVC).

[0072] The base material layer 21 may contain a colorant. By containing the colorant, the base material layer 21 is colored to a desired color. The colored base material layer can improve the design displayed by the decorative sheet 20. The colorant may contain one or more of a pigment and a dye.

[0073] The substrate layer 21 may include only a single layer or may include multiple layers. The substrate layer 21 may include a primer layer 22 such as an easy-adhesion layer. In the illustrated example, the primer layer 22 forms the first surface 21A of the substrate layer 21 and is in contact with the surface protective layer 24. The primer layer 22 may be formed from the above-mentioned thermosetting resin composition.

[0074] <Decorative Layer> The decorative layer 23 forms the design displayed by the decorative sheet 20. The design formed by the decorative layer 23 may be monochromatic. The material of the decorative layer 23 is not particularly limited. The decorative layer 23 may include, for example, a binder resin and at least one of a colorant and a luster material. In this case, the decorative layer 23 forms the design using the colorant and / or the luster material. The thickness of the decorative layer 23 may be, for example, 0.1 μm or more, 5 μm or more, 50 μm or less, 20 μm or less, 10 μm or less, or 5 μm or less.

[0075] The binder resin may contain a colorant and a luster material. The binder resin may be, for example, a urethane resin, an acrylic polyol resin, an acrylic resin, an ester resin, an amide resin, a butyral resin, a styrene resin, a urethane-acrylic copolymer, a vinyl chloride-vinyl acetate copolymer resin, a vinyl chloride-vinyl acetate-acrylic copolymer resin, a chlorinated propylene resin, a nitrocellulose resin, or a cellulose acetate resin.

[0076] The colorant may be a dye, a pigment, or a combination of a dye and a pigment. Considering weather resistance, etc., the colorant is preferably a pigment. The pigment may be a colored pigment or a fluorescent pigment. The colored pigment may be, for example, an organic pigment such as a quinacridone pigment (e.g., quinacridone red), an azo pigment (e.g., pigment red), a phthalocyanine pigment (e.g., phthalocyanine blue, phthalocyanine green), or a perylene pigment (e.g., perylene red), or an inorganic pigment such as titanium oxide or carbon black. The color of the colorant may be a chromatic color or an achromatic color. The luster material reflects light. The luster material may be, for example, aluminum flake, mica, or a pearl pigment.

[0077] In the illustrated example, the decorative layer 23 is formed on the base layer 21. The decorative layer 23 may be formed by printing or by transfer. The decorative layer 23 may be formed of a film containing a colorant and / or a glittering material.

[0078] <Backer Layer> The backer layer 26 is a layer for reinforcing the decorative sheet 20. The backer layer 26 may be a member formed in a film shape. The thickness of the backer layer 26 may be, for example, 30 μm or more and 380 μm or less.

[0079] The backer layer 26 may be transparent or opaque. When the backer layer 26 is opaque, it can conceal at least a portion of the adherend 11.

[0080] The material of the backer layer 26 is not particularly limited. The backer layer 26 may contain a resin. The resin contained in the backer layer 26 may be, for example, polyvinyl chloride resin (PVC), acrylonitrile butadiene styrene (ABS) resin, polyolefin resin, styrene resin, (meth)acrylic resin, polycarbonate resin, or polyethylene terephthalate (PET). The polyolefin resin may be polypropylene resin. Considering the above-mentioned conditions (1) to (3), the resin contained in the backer layer 26 is particularly preferably polyvinyl chloride resin (PVC), acrylonitrile butadiene styrene (ABS) resin, polyolefin resin, or polyethylene terephthalate (PET).

[0081] The backer layer 26 may further contain a plasticizer in addition to the resin. The plasticizer imparts flexibility to the resin contained in the backer layer 26. The strength against breakage of the decorative sheet 20 may be adjusted by adjusting the content of the plasticizer contained in the backer layer 26. Examples of plasticizers include ester-based plasticizers, polyester-based plasticizers, epoxy-based plasticizers, and phosphate ester-based plasticizers. The plasticizer may be contained in an amount of 31 parts by mass or more, 35 parts by mass or more, or 39 parts by mass or more per 100 parts by mass of the resin. In the backer layer 26, the plasticizer may be contained in an amount of 55 parts by mass or less, 50 parts by mass or less, or 45 parts by mass or less per 100 parts by mass of the resin.

[0082] The backer layer 26 may contain a coloring material. The backer layer 26 is colored by using the coloring material. Such a decorative sheet 20 has a design feature in the colored backer layer 26. The coloring material may contain one or more of a pigment and a dye.

[0083] <Bonding Layer> The bonding layer 25 bonds the backer layer 26 to other layers of the decorative sheet 20. The thickness of the bonding layer 25 is, for example, not less than 2 μm and not more than 30 μm.

[0084] The bonding layer 25 may contain a thermoplastic resin, a (meth)acrylic acid ester copolymer, etc. The thermoplastic resin is not particularly limited, and examples thereof include acrylic resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, polyester resin, chlorinated polypropylene, chlorinated rubber, urethane resin, epoxy resin, and styrene resin. These resins may be used alone or in combination of two or more.

[0085] <<Modifications of Decorative Sheet>> In the above-described example, the decorative sheet 20 includes the surface protective layer 24, the bonding layer 25, and the backer layer 26, but is not limited to this. The decorative sheet 20 does not have to include at least one of the surface protective layer 24, the primer layer 22, the bonding layer 25, and the backer layer 26. The decorative sheet 20 does not have to include all of the surface protective layer 24, the primer layer 22, the bonding layer 25, and the backer layer 26. Furthermore, the base layer 21 does not have to include the primer layer 22. In the above-described example, the decorative layer 23 is formed on the second surface 21B of the base layer 21, but is not limited to this. The decorative layer 23 may be formed on the first surface 21A of the base layer 21. In this case, the base layer 21 may be opaque. Furthermore, the backer layer 26 does not have to form the back surface 20B of the decorative sheet 20. The backer layer 26 may be disposed between the back side surface 20B and the decorative layer 23 .

[0086] <<Method for Evaluating Decorative Sheets>> Next, a method for evaluating decorative sheets will be described. Here, decorative sheets 20 of Examples 1 to 22 and decorative sheets 120 of Comparative Examples 1 to 8 were prepared, and each decorative sheet 20, 120 was evaluated. The decorative sheets 20 of Examples 1 to 22 are decorative sheets whose strength against break and elongation at break satisfy all of the above-mentioned conditions (1) to (3). The decorative sheets 120 of Comparative Examples 1 to 8 are decorative sheets whose strength against break and elongation at break do not satisfy at least one of the above-mentioned conditions (1) to (3). The present disclosure is not limited by the examples.

[0087] In the evaluation of the decorative sheets 20, 120, first, a first bending test and a second bending test were performed on the laminate board 12, 112 including test pieces of each decorative sheet 20, 120. Next, in the evaluation of the decorative sheets 20, 120, the changes in appearance of the test pieces of each decorative sheet 20, 120 after each bending test were observed visually or microscopically. Note that multiple test pieces were cut from each decorative sheet 20, 120, and the tensile test, first bending test, and second bending test were performed on different test pieces. The test pieces used in the tensile test were 10 mm wide and 150 mm long. On the other hand, the test pieces used in the first bending test and second bending test were 100 mm wide and 100 mm long.

[0088] <Measurement of Strength to Break and Elongation at Break> As described above, the strength to break and elongation at break of each test piece were measured through a tensile property test in accordance with JIS K 7161-1:2014 and JIS K 7130:1999. The tensile property test was performed on test pieces (test piece type 2) cut out from each decorative sheet 20, 120 using a tensile tester manufactured by Instron. The initial distance between the grips of the tensile tester was 100 mm, and the test speed, i.e., the speed at which the grips separated from each other, was 300 mm / min. The tensile property test was also performed at an ambient temperature of 23°C.

[0089] <First bending test> First, an adhesive layer 15 was formed on the second surface 20B, 120B of a test piece cut out from each decorative sheet 20, 120, and the test piece was attached to a flat cold-rolled steel plate 11 to produce a laminate sheet 12, 112. The cold-rolled steel plate 11 had a thickness of 0.6 mm. The adhesive layer 15 was "Mold Fit 50" manufactured by Nichiei Shinka Co., Ltd. The thickness of the adhesive layer 15 was 50 μm.

[0090] Next, the laminate sheet 12, 112 was pressed using a press mold 30 as shown in FIG. 6 . Specifically, the decorative sheet 20, 120 of the laminate sheet 12, 112 was covered with a protective film (not shown), and then the laminate sheet 12, 112 was placed between the male mold 31 and female mold 32 of the press mold 30. The protective film was made of polyethylene terephthalate. Next, the male mold 31 and female mold 32 were brought close to each other, and a load was applied to the press mold 30 along the normal direction of the laminate sheet 12, 112 using a press machine. This resulted in simultaneous bending of the test piece of the decorative sheet 20, 120 and the cold-rolled steel sheet 11. The width and length of the male mold 31 and female mold 32 of the press mold 30 were both 100 mm. The press speed was 70 mm / s. The load applied to the press mold 30 during pressing was 50 tons. The clearance between the male die 31 and the female die 32 during pressing was 1 mm. The temperature of the press die 30 during pressing was approximately the same as the ambient temperature, about 23° C. In FIG. 6, the adhesive layer 15 of the laminate plates 12, 112 is not shown.

[0091] After the press working, the press mold 30 was removed from the laminated plates 12, 112. In addition, the protective films that had covered the decorative films 20, 120 were peeled off from the laminated plates 12, 112.

[0092] 7 is a diagram showing the cross-sectional shape of the laminate plate 12, 112 after press processing. On the front side of the laminate plate 12, 112 (the first surface 20A, 120A of the decorative sheet 20, 120), the laminate plate 12, 112 has a pair of flat portions P1, a recessed portion P2 between the flat portions P1, and a protruding portion P3. The flat portion P1 is a portion that has not been bent. The recessed portion P2 and the protruding portion P3 are portions that have been bent. The radius of curvature of the recessed portion P2 on the first surface 20A, 120A of the decorative sheet 20, 120 was 0.44 mm, and the radius of curvature of the protruding portion P3 on the first surface 20A, 120A was 1.29 mm. The height D of the top of the convex portion P3 relative to the flat portion P1 (the distance between the flat portion P1 and the top of the convex portion P3 along the normal direction of the flat portion P1) was 6.5 mm.

[0093] Immediately after press processing, the decorative sheet 20, 120 of the laminate plate 12, 112 was checked for defects such as whitening, cracks, and breakage. In particular, the decorative sheet 20, 120 in the area including the recessed portion P2 and the protruding portion P3 was checked for defects such as whitening, cracks, and breakage. The presence or absence of defects in the decorative sheet 20, 120 was checked after the laminate plate 12, 112 was removed from the press mold 30 and the protective film was peeled off from the laminate plate 12, 112. Furthermore, after leaving the laminate plate 12, 112 at ambient temperature for 24 hours or more, the decorative sheet 20, 120 was checked for lifting from the cold-rolled steel plate 11. A 10x magnification microscope (Keyence Corporation VH-5500) was used to check for defects.

[0094] <Second Bending Test> First, laminate sheets 12, 112 were prepared in the same manner as in the first bending test. A 180° bending test was performed on each laminate sheet 12, 112 using a Type 1 testing apparatus as specified in JIS K 5600-5-1:1999, Section 6.2.1. This resulted in simultaneous bending of the decorative sheet 20, 120 test piece and the cold-rolled steel sheet 11. The laminate sheets 12, 112 were attached to the testing apparatus with the cold-rolled steel sheet 11 in contact with the mandrel. The bending of the laminate sheets 12, 112 using the testing apparatus took 2 seconds. The mandrel was made of stainless steel and had a diameter of 2 mm. The temperature of the mandrel during bending was approximately 23°C, which was approximately the same as the ambient temperature (23°C). Other conditions for carrying out the second bending test were in accordance with JIS K 5600-5-1:1999.

[0095] After the bending was completed, without removing the laminate plate 12, 112 from the testing device, the presence or absence of defects such as whitening or cracks in the decorative sheet 20, 120 of the laminate plate 12, 112 was confirmed using a microscope with a magnification of 10x (VH-5500 manufactured by Keyence Corporation).

[0096] <Configuration of test pieces of decorative sheet> Next, the layer configuration, thickness, strength against breakage, elongation at breakage, and material and thickness of the base material layer 21 of the decorative sheets 20 and 120 of each example and comparative example will be described. In addition, if the decorative sheets 20 and 120 include a backer layer 26, the material and thickness of the backer layer 26 will also be described.

[0097] In the following description of the test specimens, the order of the layers in the "layer structure" of the decorative sheet 20, 120 corresponds to the order in which the layers included in the decorative sheet 20, 120 are arranged in the direction from the first surface 20A, 120A to the second surface 20B, 120B of the decorative sheet 20, 120. For example, the description "layer structure: base layer / decorative layer" means that the decorative sheet 20 includes a base layer 21 and a decorative layer 23, and that the base layer 21 and the decorative layer 23 are stacked in this order in the direction from the first surface 20A, 120A to the second surface 20B, 120B. The description "layer structure: surface protective layer / primer layer / base layer / decorative layer" means that the surface protective layer 24, primer layer 22, base layer 21, and decorative layer 23 are stacked in this order in the direction from the first surface 20A, 120A to the second surface 20B, 120B.

[0098] In the decorative sheet 20 of Example 1, the decorative layer 23 was formed from ink. The ink contained an acrylic resin and a colorant. The ink was applied by gravure coating. The decorative layer 23 was formed by drying the ink. The thickness of the decorative layer 23 was 5 μm.

[0099] In the decorative sheet 20 of Example 7, the decorative layer 23 was formed from ink. The ink contained a urethane resin and a colorant. The ink was applied by die coating. The decorative layer 23 was formed by curing the ink. The ink was placed in a drying oven for curing. The thickness of the decorative layer 23 was 5 μm.

[0100] In the decorative sheet 20 of Example 10, the decorative layer 23 was formed from ink. The ink contained an acrylic resin and a glittering material. The glittering material was aluminum flakes. The median diameter of the aluminum flakes was 12 μm. The average thickness of the aluminum flakes was 0.2 μm. The decorative layer 23 was formed by drying the ink. The thickness of the decorative layer 23 was 5 μm.

[0101] The material, thickness, and formation method of the decorative layer 23 of the decorative sheet 20 of Example 1 are the same as or similar to the material, thickness, and formation method of the decorative layer 23 of the decorative sheets 20 of Examples 2 to 6, 12, and 22. The material, thickness, and formation method of the decorative layer 23 of the decorative sheet 20 of Example 1 are the same as or similar to the material, thickness, and formation method of the decorative layer of the decorative sheet 120 of Comparative Examples 1 to 8. The material, thickness, and formation method of the decorative layer 23 of the decorative sheet 20 of Example 7 are the same as or similar to the material, thickness, and formation method of the decorative layer 23 of the decorative sheets 20 of Examples 8 to 9, and 13 to 21. The material, thickness, and formation method of the decorative layer 23 of the decorative sheet 20 of Example 10 are the same as or similar to the material, thickness, and formation method of the decorative layer 23 of Example 11.

[0102] In the decorative sheet 20 of Example 4, the primer layer 22 was formed from a thermosetting resin composition. The thermosetting resin composition was applied by gravure coating. The thermosetting resin composition included a thermosetting compound and a curing agent. In the thermosetting resin composition, the curing agent was contained in an amount of 8 parts by mass per 100 parts by mass of the thermosetting compound. The thermosetting compound was an acrylic urethane resin. The acrylic urethane resin included an acrylic resin and a urethane resin. In the acrylic urethane resin, the weight ratio of the acrylic resin to the urethane resin was 1:9. The curing agent was m-xylylene diisocyanate (m-XDI). The primer layer 22 was formed by curing ink. The ink was placed in a drying oven for curing. The thickness of the primer layer 22 was 1 μm.

[0103] In the decorative sheet 20 of Example 10, the primer layer 22 was formed from a thermosetting resin composition. The thermosetting resin composition was applied by gravure coating. The thermosetting resin composition contained a thermosetting compound and a curing agent. The thermosetting compound was an acrylic polyol. The curing agent was an isocyanate-based curing agent. The primer layer 22 was formed by curing the thermosetting compound. The thermosetting resin composition was placed in a drying oven to cure the thermosetting compound. The primer layer 22 contained a urethane resin. The thickness of the primer layer 22 was 2 μm.

[0104] The material, thickness and formation method of the primer layer 22 of the decorative sheet 20 of Example 4 are the same as or similar to the material, thickness and formation method of the primer layer 22 of the decorative sheet 20 of Examples 5 and 6. The material, thickness and formation method of the primer layer 22 of the decorative sheet 20 of Example 4 are the same as or similar to the material, thickness and formation method of the primer layer of the decorative sheet 120 of Comparative Example 2. The material, thickness and formation method of the primer layer 22 of the decorative sheet 20 of Example 10 are the same as or similar to the material, thickness and formation method of the primer layer 22 of the decorative sheet 20 of Example 11.

[0105] (1-1) Decorative sheet 20 of Example 1 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 80 μm Strength against breakage: 130 (N) Elongation at breakage: 136 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 75 μm

[0106] (1-2) Decorative sheet 20 of Example 2 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 105 μm Strength against breakage: 160 (N) Elongation at breakage: 130 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 100 μm

[0107] (1-3) Decorative sheet 20 of Example 3 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 55 μm Strength against breakage: 84 (N) Elongation at breakage: 129 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 50 μm

[0108] (1-4) Decorative sheet 20 of Example 4 - Decorative sheet 20 Layer structure: surface protective layer / primer layer / base layer / decorative layer Thickness: 63 μm Strength against breakage: 100 (N) Elongation at breakage: 179 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 50 μm - Surface protective layer 24 Material: to be described later Forming method: After forming an uncured resin layer by gravure coating, the uncured resin layer is cured by ultraviolet irradiation Thickness: 7 μm

[0109] (1-5) Decorative sheet 20 of Example 5 Decorative sheet 20 Layer structure: surface protective layer / primer layer / base layer / decorative layer / backer layer Thickness: 163 μm Strength at break: 105 (N) Elongation at break: 155 (%) Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 50 μm Backer layer 26 Material: 100 parts by mass of polyvinyl chloride manufactured by Riken Technos Corporation mixed with 39 parts by mass of polyester plasticizer Thickness: 100 μm Surface protective layer 24 Material: described below Forming method: same as in Example 4 Thickness: 7 μm

[0110] (1-6) Decorative sheet 20 of Example 6 - Decorative sheet 20 Layer structure: surface protective layer / primer layer / base layer / decorative layer / backer layer Thickness: 123 μm Strength against break: 100 (N) Elongation at break: 151 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 50 μm - Backer layer 26 Material: A mixture of 100 parts by mass of polyvinyl chloride manufactured by Riken Technos Corporation and 39 parts by mass of polyester plasticizer Thickness: 60 μm - Surface protective layer 24 Material: See below Forming method: Same as in Example 4 Thickness: 7 μm

[0111] (1-7) Decorative sheet 20 of Example 7 - Decorative sheet 20 Layer structure: surface protective layer / base layer / decorative layer Thickness: 163 μm Strength against breakage: 32 (N) Elongation at breakage: 250 (%) - Base layer 21 Material: TPU film "SHG2393" manufactured by Seedam Thickness: 150 μm - Surface protective layer 24 Material: See below Forming method: Same as in Example 4 Thickness: 8 μm

[0112] (1-8) Decorative sheet 20 of Example 8 - Decorative sheet 20 Layer structure: surface protective layer / base layer / decorative layer / backer layer Thickness: 263 μm Strength against breakage: 67 (N) Elongation at breakage: 270 (%) - Base layer 21 Material: TPU film "SHG2393" manufactured by Seedam Co., Ltd. Thickness: 150 μm - Backer layer 26 Material: 100 parts by mass of polyvinyl chloride manufactured by Riken Technos Corporation mixed with 39 parts by mass of polyester plasticizer Thickness: 100 μm - Surface protective layer 24 Material: See below Forming method: Same as in Example 4 Thickness: 8 μm

[0113] (1-9) Decorative sheet 20 of Example 9 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 155 μm Strength against breakage: 35 (N) Elongation at breakage: 431 (%) - Base layer 21 Material: TPU film "SHG2393" manufactured by Seedam Co., Ltd. Thickness: 150 μm

[0114] (1-10) Decorative sheet 20 of Example 10 - Decorative sheet 20 Layer structure: base layer / primer layer / decorative layer Thickness: 157 μm Strength against break: 23 (N) Elongation at break: 530 (%) - Base layer 21 Material: Low-density polyethylene (LDPE) "KF260T" manufactured by Japan Polyethylene Co., Ltd. Thickness: 150 μm

[0115] (1-11) Decorative sheet 20 of Example 11 - Decorative sheet 20 Layer structure: base layer / primer layer / decorative layer Thickness: 87 μm Strength against break: 35 (N) Elongation at break: 700 (%) - Base layer 21 Material: A resin composition obtained by mixing 0.12 parts by mass of a hydroxyphenyl triazine-based ultraviolet absorber (TINUVIN 460 manufactured by BASF) and 0.15 parts by mass of a hydroxyphenyl triazine-based ultraviolet absorber (ADEKA STAB LA-46 manufactured by ADEKA Corporation) with 100 parts by mass of polypropylene-based resin, and hot-melt-extruded into a sheet using a T-die extruder Thickness: 80 μm

[0116] (1-12) Decorative sheet 20 of Example 12 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 105 μm Strength at break: 35 (N) Elongation at break: 286 (%) - Base layer 21 Material: 100 parts by mass of polyvinyl chloride (manufactured by Riken Technos Corporation) mixed with 39 parts by mass of polyester plasticizer Thickness: 100 μm

[0117] (1-13) Decorative sheet 20 of Example 13 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 85 μm Strength against breakage: 75 (N) Elongation at breakage: 380 (%) - Base layer 21 Material: TPU film "SNY97" manufactured by Okura Kogyo Co., Ltd. Thickness: 80 μm

[0118] (1-14) Decorative sheet 20 of Example 14 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 85 μm Strength against breakage: 25 (N) Elongation at breakage: 254 (%) - Base layer 21 Material: TPU film "SNY90" manufactured by Okura Kogyo Co., Ltd. Thickness: 80 μm

[0119] (1-15) Decorative sheet 20 of Example 15 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 155 μm Strength against breakage: 65 (N) Elongation at breakage: 312 (%) - Base layer 21 Material: TPU film "SNYD85" manufactured by Okura Kogyo Co., Ltd. Thickness: 150 μm

[0120] (1-16) Decorative sheet 20 of Example 16 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 155 μm Strength against breakage: 80 (N) Elongation at breakage: 502 (%) - Base layer 21 Material: TPU film "PX98" manufactured by Nippon Matai Co., Ltd. Thickness: 150 μm

[0121] (1-17) Decorative sheet 20 of Example 17 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 130 μm Strength against breakage: 38 (N) Elongation at breakage: 660 (%) - Base layer 21 Material: TPU film "PX93" manufactured by Nippon Matai Co., Ltd. Thickness: 125 μm

[0122] (1-18) Decorative sheet 20 of Example 18 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 155 μm Strength against breakage: 44 (N) Elongation at breakage: 648 (%) - Base layer 21 Material: TPU film "SHG2393" manufactured by Seedom Co., Ltd. Thickness: 150 μm

[0123] (1-19) Decorative sheet 20 of Example 19 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 155 μm Strength against breakage: 40 (N) Elongation at breakage: 730 (%) - Base layer 21 Material: TPU film "SHG2086" manufactured by Seedom Co., Ltd. Thickness: 150 μm

[0124] (1-20) Decorative sheet 20 of Example 20 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 205 μm Strength against breakage: 85 (N) Elongation at breakage: 600 (%) - Base layer 21 Material: TPU film "Platilon (registered trademark) 4201U" manufactured by Covestro AG Thickness: 200 μm

[0125] (1-21) Decorative sheet 20 of Example 21 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 105 μm Strength at break: 43 (N) Elongation at break: 484 (%) - Base layer 21 Material: TPU film "Platilon (registered trademark) 4201U" manufactured by Covestro AG Thickness: 100 μm

[0126] (1-22) Decorative sheet 20 of Example 22 - Decorative sheet 20 Layer structure: base layer / decorative layer Thickness: 80 μm Strength against breakage: 71 (N) Elongation at breakage: 142 (%) - Base layer 21 Material: Polyester film "Lumirror (registered trademark) Easy Forming Film QV22" manufactured by Toray Industries, Inc. Thickness: 75 μm

[0127] (2-1) Decorative sheet 120 of Comparative Example 1 - Decorative sheet 120 Layer structure: base layer / decorative layer Thickness: 30 μm Strength against breakage: 38 (N) Elongation at breakage: 102 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 25 μm

[0128] (2-2) Decorative sheet 120 of Comparative Example 2 Decorative sheet 120 Layer structure: surface protective layer / primer layer / base layer / decorative layer Thickness: 38 μm Strength against breakage: 44 (N) Elongation at breakage: 126 (%) Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 25 μm Surface protective layer 24 Material: See below Forming method: Same as in Example 4 Thickness: 7 μm

[0129] (2-3) Decorative sheet 120 of Comparative Example 3 - Decorative sheet 120 Layer structure: base layer / decorative layer / backer layer Thickness: 130 μm Strength against breakage: 64 (N) Elongation at breakage: 107 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 25 μm - Backer layer 26 Material: A mixture of 100 parts by mass of polyvinyl chloride manufactured by Riken Technos Corporation and 39 parts by mass of polyester-based plasticizer Thickness: 100 μm

[0130] (2-4) Decorative sheet 120 of Comparative Example 4 - Decorative sheet 120 Layer structure: base layer / decorative layer Thickness: 130 μm Strength at break: 206 (N) Elongation at break: 132 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 125 μm

[0131] (2-5) Decorative sheet 120 of Comparative Example 5 - Decorative sheet 120 Layer structure: base layer / decorative layer Thickness: 155 μm Strength at break: 251 (N) Elongation at break: 145 (%) - Base layer 21 Material: PET film "Cosmoshine A4360" manufactured by Toyobo Co., Ltd. Thickness: 150 μm

[0132] (2-6) Decorative sheet 120 of Comparative Example 6 - Decorative sheet 120 Layer structure: base layer / decorative layer Thickness: 130 μm Strength against breakage: 55 (N) Elongation at breakage: 8 (%) - Base layer 21 Material: Acrylic resin (PMMA) film "HBS 006H" manufactured by Mitsubishi Chemical Corporation Thickness: 125 μm

[0133] (2-7) Decorative sheet 120 of Comparative Example 7 - Decorative sheet 120 Layer structure: base layer / decorative layer Thickness: 130 μm Strength against breakage: 50 (N) Elongation at breakage: 5 (%) - Base layer 21 Material: Acrylic resin (PMMA) film "015NAH" manufactured by Kaneka Corporation Thickness: 125 μm

[0134] (2-8) Decorative sheet 120 of Comparative Example 8 - Decorative sheet 120 Layer structure: base layer / decorative layer Thickness: 55 μm Strength against breakage: 16 (N) Elongation at breakage: 44 (%) - Base layer 21 Material: "Kureha KFC Film FT-50Y" manufactured by Kureha Extron Co., Ltd. (co-extruded multilayer film consisting of a polyvinylidene fluoride (PVDF) layer and an acrylic resin layer). However, the acrylic resin layer is arranged facing the decorative layer. Thickness: 50 μm

[0135] In Examples 4 to 8 and Comparative Example 2, the material used to form the surface protective layer 24 was 100 parts by weight of ultraviolet-curable resin to which approximately 0.1 to 5 parts by weight of a photopolymerization initiator was added. The ultraviolet-curable resin was a mixture of a bifunctional polycarbonate (meth)acrylate and a hexafunctional urethane (meth)acrylate oligomer in a weight ratio of 94:6. The weight-average molecular weight of the bifunctional polycarbonate (meth)acrylate was 10,000. The weight-average molecular weight of the hexafunctional urethane (meth)acrylate oligomer was 6,000.

[0136] <Evaluation Results> The evaluation results of Examples 1 to 12 and Comparative Examples 1 to 8 are shown in Table 1. The evaluation results of Examples 13 to 22 are shown in Table 2. In Tables 1 and 2, "crack resistance" refers to the resistance to crack formation in the decorative sheets 20, 120. In "crack resistance" in Tables 1 and 2, A to D mean the following: A: No cracks were observed. B: Cracks were observed, but they were very small and did not affect the appearance. C: Cracks that affected the appearance were observed. D: Cracks that significantly affected the appearance were observed. Furthermore, in Tables 1 and 2, "break resistance" refers to the resistance to breakage of the decorative sheets 20, 120. In "break resistance" in Tables 1 and 2, A to D mean the following: A: No breaks were observed. B: Breaks were observed, but they were very small and did not affect the appearance. C: Breaks that affected the appearance were observed. D: Breakage that significantly affected the appearance was observed. In Tables 1 and 2, "whitening resistance" refers to the resistance of the decorative sheet 20, 120 to whitening. In "whitening resistance" in Tables 1 and 2, A to D mean the following: A: No whitening was observed. B: Whitening was observed, but it was slight and did not affect the appearance. C: Whitening that affected the appearance was observed. D: Whitening that significantly affected the appearance was observed. In Tables 1 and 2, "lifting resistance" refers to the resistance of the decorative sheet to lifting. In "lifting resistance" in Tables 1 and 2, A to D mean the following: A: No lifting from the steel plate was observed. B: Lifting from the steel plate was observed, but it was slight and did not affect the appearance. C: Lifting from the adherend that significantly affected the steel plate was observed. D: Lifting from the adherend that significantly affected the steel plate was observed.

[0137]

[0138]

[0139] As can be seen from Tables 1 and 2, in the first bending test and the second bending test, no whitening, cracks, breaks, or lifting from the adherend that would affect the appearance was observed in the decorative sheets 20 of Examples 1 to 22. On the other hand, in the first bending test and / or the second bending test, in the decorative sheets 120 of Comparative Examples 1 to 8, whitening, cracks, breaks, and / or lifting from the adherend that would significantly affect the appearance was observed.

[0140] FIG. 8 shows the strength against breakage and elongation at breakage of the decorative sheets 20, 120 of Examples 1 to 22 and Comparative Examples 1 to 8. In FIG. 8, the above-mentioned conditions (1) to (3) are indicated by a thick dashed line, a thick dashed line, and a thick dashed double-dot line, respectively. Also, in FIG. 8, condition (4) is indicated by a thin dashed line. Also, in FIG. 8, the region satisfying all of conditions (1) to (4) is surrounded by a thick solid line. As can be seen from FIG. 8, all of Examples 1 to 22 satisfy all of conditions (1) to (3). Furthermore, all of Examples 1 to 8 and 12 satisfy all of conditions (1) to (4). Examples 1 to 22 satisfy all of conditions (1) to (3) and conditions (5) to (7). On the other hand, all of Comparative Examples 1 to 8 do not satisfy at least one of conditions (1) to (3). From Figure 8, it can be seen that the decorative sheet 20 that satisfies all of the conditions (1) to (3) is less likely to suffer from problems such as whitening, cracking, breaking, and lifting when bent at ambient temperatures, and has good bending processability.

[0141] The decorative sheet 20 according to the embodiment described above includes a base layer 21 and a decorative layer 23. The decorative layer 23 is formed on one surface 21B or 21A of the base layer 21. In a tensile property test performed at a test speed of 300 mm / min and an ambient temperature of 23°C, the decorative sheet 20 satisfies the following formulas, where x (N) and y (%) represent the strength at break and the elongation at break. y > 30, y > -0.85x + 170, and 0 < x < 200. This decorative sheet 20 exhibits excellent bending processability and is less susceptible to problems such as whitening, cracking, breakage, and lifting, even when bent together with an adherend 11 at ambient temperature. Therefore, there is no need to heat the decorative sheet 20 when bending a laminate plate 12 to produce a decorative member 10. Furthermore, by decorating the adherend 11 by covering it with the decorative sheet 20, the amount of volatile organic compounds used and the amount of carbon dioxide emitted can be effectively reduced compared to decorating the adherend 11 by painting, thereby reducing the environmental impact during the production of the decorative member 10.

[0142] In the embodiment described above, the elongation y (%) at break of the decorative sheet 20 is 300<y<425. In this case, the decorative sheet 20 is easy to manufacture.

[0143] In the embodiment described above, the base material layer 21 contains polyethylene terephthalate or thermoplastic polyurethane. In this case, even when bending is performed together with the adherend 11 at ambient temperature, problems such as whitening, cracking, breakage, and lifting are unlikely to occur, and bending processability is good.

[0144] In the embodiment described above, the decorative sheet 20 further includes a surface protection layer 24 that forms the front side 20A of the decorative sheet 20. In this case, the decorative sheet 20 can be provided with scratch resistance, abrasion resistance, weather resistance, or chemical resistance.

[0145] In the embodiment described above, the surface protective layer 24 contains polycarbonate (meth)acrylate and / or urethane (meth)acrylate. In this case, even when bending is performed together with the adherend 11 at ambient temperature, problems such as whitening, cracking, breakage, and lifting are unlikely to occur, and bending processability is good.

[0146] In the embodiment described above, the decorative sheet 20 further includes a backer layer 26. The backer layer 26 forms the back surface 20B of the decorative sheet 20 or is disposed between the back surface 20B and the decorative layer 23. In this case, the strength of the decorative sheet 20 can be improved.

[0147] In the embodiment described above, the backer layer 26 contains polyvinyl chloride. In this case, even when bending is performed together with the adherend 11 at ambient temperature, problems such as whitening, cracking, breakage, and lifting are unlikely to occur, and bending workability is good.

[0148] The decorative member 10 according to the embodiment described above includes the decorative sheet 20. Such a decorative member 10 is less likely to suffer from problems such as whitening, cracking, breaking, or lifting of the decorative sheet 20, and presents a good aesthetic appearance.

[0149] The moving body 1 according to the embodiment described above includes the above-mentioned decorative member 10. Such a moving body 1 is less likely to suffer from problems such as whitening, cracking, breaking, or lifting of the decorative sheet 20, and presents a good aesthetic appearance.

[0150] The method for manufacturing the decorative member 10 according to the embodiment described above includes the steps of preparing the decorative sheet 20, adhering the decorative sheet 20 to a steel plate 11, and bending the steel plate 11 with the decorative sheet 20 adhered thereto at a temperature of −5°C to 40°C. This method for manufacturing the decorative member 10 effectively reduces the amount of volatile organic compounds used and carbon dioxide emissions. Furthermore, the decorative sheet 20 is less likely to suffer from whitening, cracks, breakage, or lifting, making it possible to manufacture a decorative member 10 that exhibits a beautiful appearance.

[0151] Although several modifications of the above-described embodiment have been described, it is of course possible to combine a plurality of modifications as appropriate.

Claims

1. A decorative sheet comprising: a base layer; and a decorative layer formed on one surface of the base layer, wherein, in a tensile property test conducted at a test speed of 300 mm / min and an ambient temperature of 23°C, the strength to break and the elongation at break are x (N) and y (%), respectively, and the following formulas are satisfied: y > 30, y > -0.85x + 170, 0 < x < 200.

2. The decorative sheet according to claim 1, which satisfies the following condition: 30<y<425.

3. The decorative sheet according to claim 1, wherein the base layer comprises polyethylene terephthalate or thermoplastic polyurethane.

4. The decorative sheet according to claim 1, further comprising a surface protection layer forming a front surface of the decorative sheet.

5. The decorative sheet according to claim 4, wherein the surface protective layer contains polycarbonate (meth)acrylate and / or urethane (meth)acrylate.

6. The decorative sheet according to claim 1, further comprising a backer layer forming a back surface of the decorative sheet or disposed between the back surface of the decorative sheet and the decorative layer.

7. The decorative sheet according to claim 6, wherein the backer layer comprises polyvinyl chloride.

8. A decorative member comprising the decorative sheet according to any one of claims 1 to 7.

9. A moving body comprising the decorative member according to claim 8.

10. An architectural structure comprising the decorative member according to claim 8.

11. A method for manufacturing a decorative member, comprising the steps of: preparing a decorative sheet according to any one of claims 1 to 7; adhering the decorative sheet to a steel plate; and bending the steel plate with the decorative sheet adhered thereto at a temperature of -5°C or higher and 40°C or lower.

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