Decorative sheet and method for producing same

Abstract

This decorative sheet comprises at least a substrate layer and a brilliant pigment layer, wherein, when a cross-section in the thickness direction of a surface portion of the substrate layer on the brilliant pigment layer side is observed using a scanning electron microscope, the substrate layer exhibits a maximum height roughness Rz (μm) of elements, as defined by JIS B0601-2013, of not more than 7.0 μm, and a ratio (Ra / Rsm) of the value of the arithmetic mean roughness (Ra) (μm) to the value of the average length Rsm (μm) of elements of not more than 0.040.

Description

Decorative sheet and method for manufacturing the same

[0001] This disclosure relates to decorative sheets and methods for manufacturing the same.

[0002] Decorative sheets are known to be used for decorative purposes on items such as furniture and fixtures, and are applied by laminating them to the surface of the item.

[0003] For example, in a decorative sheet with a pattern, a printed layer expressing the pattern is formed on a base layer, and the pattern on this printed layer gives the article a design (see Patent Document 1).

[0004] International Publication No. 2007 / 116942

[0005] In recent years, decorative sheets (wrapping sheets) have been increasingly used for decorative purposes on the exteriors of automobiles. These decorative sheets for automobile exteriors are often required to create metallic-looking designs, for example.

[0006] One possible method for imparting a metallic-looking design to a decorative sheet is to laminate a glossy pigment layer containing glossy pigments onto the decorative sheet. However, when laminating a glossy pigment layer onto a decorative sheet, it is necessary to use an ink containing glossy pigments and form the glossy pigment layer as a thin printed layer using printing techniques such as gravure printing.

[0007] When printing inks containing luminous pigments using printing techniques such as gravure printing, it is difficult to use large-sized luminous pigments. Therefore, it is desirable to use small-sized luminous pigments.

[0008] However, when the size of the luminous pigments becomes smaller, a problem arises in that metallic designs become difficult to achieve. Metallic designs are those with a high degree of angle dependence of brightness. For example, when observing a decorative sheet, if the angle dependence of brightness is low, it becomes difficult to recognize it as a metallic design even if the brightness is high.

[0009] Under these circumstances, the primary objective of this disclosure is to provide a decorative sheet comprising at least a lustrous pigment layer and a substrate layer, which has an excellent metallic design. Furthermore, the disclosure also aims to provide a method for manufacturing the decorative sheet.

[0010] The inventors of this disclosure have diligently studied to solve the aforementioned problems. As a result, they have found that, in a decorative sheet comprising a base layer and a glossy pigment layer, an uneven shape is formed on the surface portion of the base layer on the glossy pigment layer side, and when the cross-section of the surface portion in the thickness direction is observed with a scanning electron microscope, the maximum height roughness Rz (μm) of the elements, as defined in JIS B0601-2013, is set to a predetermined value or less, and furthermore, the ratio of the arithmetic mean roughness Ra (μm) to the average length Rsm (μm) of the elements (Ra / Rsm) is set to a predetermined value or less, thereby exhibiting an excellent metallic-like design. This disclosure was completed by further studies based on these findings.

[0011] That is, the present disclosure provides inventions in the following embodiments: Item 1. A decorative sheet comprising at least a base layer and a lustrous pigment layer, wherein, when the cross-section in the thickness direction of the surface portion on the lustrous pigment layer side of the base layer is observed with a scanning electron microscope, the maximum height roughness Rz (μm) of the elements as defined in JIS B0601-2013 is 7.0 μm or less, and the ratio of the arithmetic mean roughness Ra (μm) to the average length Rsm (μm) of the elements (Ra / Rsm) is 0.040 or less. Item 2. The decorative sheet according to Item 1, wherein when the cross-sections in the thickness direction of the surface portions on the lustrous pigment layer side and the opposite side of the base layer are observed with a scanning electron microscope, at least one of the surface portions has an arithmetic mean roughness Ra of 0.25 μm or more. Item 3. A decorative sheet according to claim 1 or 2, further comprising a first primer layer between the base material layer and the lustrous pigment layer. Claim 4. A decorative sheet according to any one of claims 1 to 3, further comprising a surface protective layer. Claim 5. A decorative sheet according to claim 4, further comprising a second primer layer in contact with the surface of the surface protective layer on the base material layer side. Claim 6. A decorative sheet according to any one of claims 1 to 5, further comprising an adhesive layer as the outermost layer. Claim 7. A decorative sheet according to any one of claims 1 to 6, for use in automotive exteriors. Claim 8. A method for manufacturing a decorative sheet, comprising at least a base layer and a glossy pigment layer, comprising at least a step of laminating the base layer and the glossy pigment layer to obtain a laminate constituting the decorative sheet, wherein, when the cross-section in the thickness direction of the surface portion on the glossy pigment layer side of the base layer is observed with a scanning electron microscope, the maximum height roughness of the elements as defined in JIS B0601-2013 is 7.0 μm or less, and the ratio of the numerical value of the arithmetic mean roughness Ra (μm) to the numerical value of the numerical value of the average length Rsm (μm) of the elements (Ra / Rsm) is 0.040 or less. Item 9. A decorative article having a decorative sheet according to any one of items 1 to 7 attached to the outer surface of the article. Item 10. An automobile having a decorative sheet according to any one of items 1 to 7 attached to the body of the automobile.

[0012] According to this disclosure, it is possible to provide a decorative sheet comprising at least a lustrous pigment layer and a substrate layer, which has an excellent metallic design. Furthermore, according to this disclosure, it is possible to provide a method for manufacturing the decorative sheet.

[0013] This is a schematic diagram of the cross-sectional structure of one form of the decorative sheet of this disclosure. This is a schematic diagram of the cross-sectional structure of one form of the decorative sheet of this disclosure. This is a schematic diagram of the cross-sectional structure of one form of the decorative sheet of this disclosure. This is a schematic diagram of the cross-sectional structure of one form of the decorative sheet of this disclosure. This is a schematic diagram of the cross-sectional structure of one form of the decorative sheet of this disclosure. This is a schematic diagram of the cross-sectional structure of one form of the decorative sheet of this disclosure. This is a schematic diagram of the cross-sectional structure of one form of the decorative sheet of this disclosure.

[0014] [Decorative Sheet] The decorative sheet of this disclosure comprises at least a base layer and a glossy pigment layer, wherein, when the cross-section in the thickness direction of the surface portion on the glossy pigment layer side of the base layer is observed with a scanning electron microscope, the maximum height roughness Rz (μm) of the elements as defined in JIS B0601-2013 is 7.0 μm or less, and the ratio of the arithmetic mean roughness Ra (μm) to the average length Rsm (μm) of the elements (Ra / Rsm) is 0.040 or less. The decorative sheet of this disclosure, having such a configuration, has an excellent metallic design.

[0015] The decorative sheets of this disclosure will be described in detail below with reference to Figures 1 to 7. In this specification, numerical ranges indicated by "~" mean "greater than or equal to" and "less than or equal to". For example, the notation 2 to 15 mm means 2 mm or more and 15 mm or less. In numerical ranges described in stages in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Alternatively, upper and lower limits, upper and lower limits, or lower and lower limits described separately may be combined to form numerical ranges. Furthermore, in numerical ranges described in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples. In this specification, "(meth)acrylate" means "acrylate or methacrylate," and other similar terms have the same meaning.

[0016] (Laminated structure and physical properties of the decorative sheet) The decorative sheet 10 of this disclosure comprises, for example, a base layer 1 and a lustrous pigment layer 2, as shown in Figures 1 to 7. When the cross-section in the thickness direction of the surface portion on the lustrous pigment layer 2 side of the base layer 1 is observed with a scanning electron microscope, the maximum height roughness Rz (μm) of the elements, as defined in JIS B0601-2013, is 7.0 μm or less, and the ratio of the arithmetic mean roughness Ra (μm) to the average length Rsm (μm) of the elements (Ra / Rsm) is 0.040 or less.

[0017] The decorative sheet of this disclosure is used to decorate articles by being attached (laminated) to the outer surface of articles, such as the exterior of automobiles. In the decorative sheet 10 of this disclosure, as long as the glossy pigment layer 2 is visible from the observer's side, the predetermined surface irregularity shape on the glossy pigment layer 2 side of the base layer 1 may be located on the observer's side or on the opposite side when the decorative sheet is applied to decorate an article. In the laminated configuration of the decorative sheet 10 shown in Figures 1 to 7, the upper side of the decorative sheet 10 is the observer's side and the lower side is the article's side. In the decorative sheet 10 of Figures 1, 2, 4 and 5, the predetermined surface irregularity shape on the glossy pigment layer 2 side of the base layer 1 is located on the observer's side when the decorative sheet 10 is applied to decorate an article. In the decorative sheet 10 shown in Figures 3, 6, and 7, the predetermined surface irregularities on the lustrous pigment layer 2 side of the base layer 1 are located on the opposite side from the observer when the decorative sheet 10 is applied to decorate an article.

[0018] As shown in Figures 2 to 7, in addition to the base layer 1 and the glossy pigment layer 2, the decorative sheet 10 of this disclosure may further include one or more other layers at arbitrary positions, depending on the function to be imparted to the decorative sheet, such as a surface protection layer 3, a first primer layer 4, a second primer layer 5, an adhesive layer 6, and even a transparent resin layer (not shown).

[0019] For example, the decorative sheet 10 shown in Figures 2 to 7 comprises a base layer 1 and a glossy pigment layer 2, in addition to a surface protection layer 3. In the decorative sheet 10 shown in Figures 2, 4, and 5, the surface protection layer 3 is formed on the side of the base layer 1 that has the predetermined surface uneven shape. In the decorative sheet 10 shown in Figures 3, 6, and 7, the surface protection layer 3 is formed on the side of the base layer 1 that is opposite to the side with the predetermined surface uneven shape. In the decorative sheet 10, the surface protection layer 3 is positioned on the observer's side.

[0020] The decorative sheet 10 shown in Figures 4 to 7 includes a first primer layer 4 between the base layer 1 and the lustrous pigment layer 2. In the decorative sheet 10 shown in Figures 4 to 7, the base layer 1 and the lustrous pigment layer 2 are laminated via the first primer layer 4. In the decorative sheet 10 shown in Figures 4 to 7, the base layer 1 and the first primer layer 4 are adjacent and in contact with each other, and the first primer layer 4 and the lustrous pigment layer 2 are adjacent and in contact with each other. The first primer layer 4 is laminated on the surface of the base layer 1 with the predetermined surface uneven shape, and has a surface uneven shape corresponding to the predetermined surface uneven shape of the base layer 1. The lustrous pigment layer 2 is laminated on the surface of the first primer layer 4 with the said surface uneven shape.

[0021] The decorative sheets 10 shown in Figures 5 to 7 include a second primer layer 5 that is in contact with the surface of the surface protective layer 3 on the substrate layer 1 side. In the decorative sheet 10 of Figure 5, the surface protective layer 3 and the glossy pigment layer 2 are laminated via the second primer layer 5. In the decorative sheets 10 of Figures 6 and 7, the surface protective layer 3 and the substrate layer 1 are laminated via the second primer layer 5.

[0022] In the decorative sheet 10 shown in Figure 7, an adhesive layer 6 is laminated on the side of the lustrous pigment layer 2 opposite to the base layer 1. The adhesive layer 6 constitutes the outermost layer on one side of the decorative sheet 10.

[0023] The laminated structures of the decorative sheets of this disclosure include: a laminated structure in which a base layer and a lustrous pigment layer are laminated; a laminated structure in which a base layer, a lustrous pigment layer, and a surface protection layer are laminated in this order; a laminated structure in which a base layer, a first primer layer, a lustrous pigment layer, and a surface protection layer are laminated in this order; a laminated structure in which a base layer, a first primer layer, a lustrous pigment layer, a second primer layer, and a surface protection layer are laminated in this order; a laminated structure in which a lustrous pigment layer and a base layer are laminated; a laminated structure in which a lustrous pigment layer, a first primer layer, a base layer, and a surface protection layer are laminated in this order; a laminated structure in which a lustrous pigment layer, a first primer layer, a base layer, a second primer layer, and a surface protection layer are laminated in this order; and an adhesive layer, a lustrous pigment layer, a first primer layer, a base layer, a second primer layer, and a surface protection layer are laminated in this order. Examples include a laminated structure in which a backer layer / first primer layer / lustrous pigment layer / second primer layer / substrate layer / surface protection layer are laminated in this order; and a laminated structure in which a backer layer / first primer layer / lustrous pigment layer / second primer layer / substrate layer / second primer layer / surface protection layer are laminated in this order. In addition, a color layer may be provided in the area in contact with the lustrous pigment layer in order to adjust the color tone. When the color layer is on the observer side relative to the lustrous pigment layer, the color density of the color layer is set to an extent that does not impair the brightness of the lustrous pigment layer. In the decorative sheet of this disclosure, the transparent resin layer may be colored and provided as a color layer, or both the transparent resin layer and the color layer may be laminated.

[0024] Figure 1 shows a schematic cross-sectional view of an example of a decorative sheet in which a base layer and a lustrous pigment layer are laminated in that order, as one aspect of the laminated structure of the decorative sheet of this disclosure. Figure 2 shows a schematic cross-sectional view of an example of a decorative sheet in which a base layer, a lustrous pigment layer, and a surface protection layer are laminated in that order, as one aspect of the laminated structure of the decorative sheet of this disclosure. Figure 3 shows a schematic cross-sectional view of an example of a decorative sheet in which a lustrous pigment layer, a base layer, and a surface protection layer are laminated in that order, as one aspect of the laminated structure of the decorative sheet of this disclosure. Figure 4 shows a schematic cross-sectional view of an example of a decorative sheet in which a base layer, a first primer layer, a lustrous pigment layer, and a surface protection layer are laminated in that order, as one aspect of the laminated structure of the decorative sheet of this disclosure. Figure 5 shows a schematic cross-sectional view of an example of a decorative sheet in which a base layer, a first primer layer, a lustrous pigment layer, a second primer layer, and a surface protection layer are laminated in that order, as one aspect of the laminated structure of the decorative sheet of this disclosure. Figure 6 shows a schematic cross-sectional view of an example of a decorative sheet in which a glossy pigment layer / first primer layer / substrate layer / second primer layer / surface protection layer are laminated in the order shown, as one aspect of the laminated structure of the decorative sheet of the present disclosure. Figure 7 shows a schematic cross-sectional view of an example of a decorative sheet in which an adhesive layer / glossy pigment layer / first primer layer / substrate layer / second primer layer / surface protection layer are laminated in the order shown, as one aspect of the laminated structure of the decorative sheet of the present disclosure.

[0025] In the decorative sheet 10, the ratio of the total thickness of the base layer 1, the glossy pigment layer 2, the optional surface protection layer 3, the optional first primer layer 4, the optional second primer layer 5, and the optional adhesive layer 6 to the thickness (total thickness) of the laminate constituting the decorative sheet 10 is, for example, 80% or more, preferably 90% or more, and more preferably 95% or more.

[0026] As a specific example, if the decorative sheet 10 of this disclosure includes a base layer 1, a glossy pigment layer 2, a surface protection layer 3, and a first primer layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the decorative sheet 10 is, for example, 80% or more, preferably 90% or more, and more preferably 95% or more. Also, if the decorative sheet 10 of this disclosure includes a base layer 1, a glossy pigment layer 2, a surface protection layer 3, a first primer layer 4, and a second primer layer 5, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the decorative sheet 10 is, for example, 80% or more, preferably 90% or more, and more preferably 95% or more. Furthermore, if the decorative sheet 10 of this disclosure includes an adhesive layer 6, a base layer 1, a glossy pigment layer 2, a surface protective layer 3, a first primer layer 4, and a second primer layer 5, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the decorative sheet 10 is, for example, 80% or more, preferably 90% or more, and more preferably 95% or more.

[0027] The decorative sheet 10 of this disclosure is preferably evaluated as "A" in the following (evaluation criteria for metallic design) when the metallic design is evaluated from the surface side of the protective layer. Furthermore, it is preferable that the following (evaluation criteria for brightness, observation angle 15°, illumination 135°) and (evaluation criteria for brightness, observation angle 75°, illumination 135°) are evaluated as "very bright".

[0028] [Evaluation of the metallic appearance of decorative sheets] The metallic appearance of the decorative sheet will be evaluated from the observer's side (surface protective layer side). In evaluating the metallic appearance, visual evaluation and, as a reference value, evaluation using a colorimeter will be performed. Visual evaluation will be performed using the standard light source D defined by the International Commission on Illumination (CIE). 65The evaluation is conducted in a room with a lamp installed on the ceiling. For specular reflection evaluation, the object to be evaluated is held at eye level, with the surface angled at 45° relative to the ground. For evaluations other than specular reflection, the object to be evaluated is fixed to a table or similar object at a position lower than eye level. The surface of the object to be evaluated is viewed from a direction of 45° relative to the ground. For metallic effect evaluation, the brightness observed in specular reflection and the difference in brightness between specular reflection and non-specular reflection are checked. The larger both are, the better the metallic effect is considered to be.

[0029] The colorimeter evaluation will employ a light source with illumination from a single direction (45° direction) and two-angle reception (multi-angle measurement at two angles, 15° and 45°, as viewed from the specularly reflected light). The specific evaluation conditions are as follows: • Equipment: Commercially available colorimeter • Optical system: 45° illumination, observation angles 15° and 45° • Measurement wavelength range: 400-700 nm • Observation light source: D 65 • Light-receiving element: Blue-sensitized silicon photodiode • Measurement item: Brightness L * Value (JIS Z 8781-4) Here, the observation angle of 15° is used to evaluate the brightness as a metallic tone near specular reflection. The observation angle of 45° is measured as the brightness at a representative angle other than specular reflection. The angle dependence of brightness, which is one of the characteristics of metals, is L at the observation angle of 15°. * From the value, L is observed at an angle of 45°. * The difference in values ​​is evaluated, and the larger the value, the more metallic the material is judged to be. However, the color measurement results from this colorimeter are supplementary data to support the visual evaluation of metallic design and cannot be considered an absolute value that defines metallicity.

[0030] The criteria for visually evaluating a "metallic design" are as follows: (Visual evaluation criteria for metallic designs) A: It appears dazzlingly bright in specular reflection, and dark at the other observation angle. B: It appears bright in specular reflection, and slightly dark at the other observation angle. C: It appears slightly bright in specular reflection, and slightly bright at the other observation angle.

[0031] (Each layer constituting the decorative sheet) [Base layer 1] The base layer 1 is a layer (resin sheet, resin film) that serves as a support in the decorative sheet 10 of this disclosure.

[0032] In the decorative sheet 10 of this disclosure, when the cross-section in the thickness direction of the surface portion on the lustrous pigment layer 2 side of the base layer 1 is observed with a scanning electron microscope, the maximum height roughness Rz (μm) of the elements as defined in JIS B0601-2013 is 7.0 μm or less, and the ratio of the arithmetic mean roughness Ra (μm) to the average length Rsm (μm) of the elements (Ra / Rsm) is 0.040 or less. In the decorative sheet 10 of this disclosure, since the lustrous pigment layer 2 is laminated on the surface uneven shape, even when printing ink containing small lustrous pigments is printed using printing techniques such as gravure printing, the angle dependence of the brightness of the decorative sheet 10 becomes large, and an excellent metallic design is expressed. In the decorative sheet 10 of this disclosure, even when a first primer layer 4 is laminated between the base layer 1 and the glossy pigment layer 2, if the first primer layer 4 has a surface uneven shape corresponding to the predetermined surface uneven shape of the base layer 1, the glossy pigment layer 2 will be laminated on the surface of the surface uneven shape of the first primer layer 4, and a similarly excellent metallic design will be expressed.

[0033] In the decorative sheet 10 of this disclosure, the maximum height roughness Rz (μm) of the base layer 1 may be 7.0 μm or less, but from the viewpoint of more favorably exhibiting the effects of the invention of this disclosure, it is preferably 5.0 μm or less, more preferably 4.0 μm or less, and even more preferably 3.0 μm or less. For example, the lower limit of the maximum height roughness Rz (μm) is 0.5 μm.

[0034] Furthermore, the ratio of the arithmetic mean roughness Ra (μm) to the average length Rsm (mm) of the elements (Ra / Rsm) of the base layer 1 should be 0.040 or less, but from the viewpoint of more favorably exhibiting the effects of the present invention, it is preferably 0.030 or less, more preferably 0.020 or less, and even more preferably 0.010 or less. For example, the lower limit of this ratio is 0.001.

[0035] The method for measuring the arithmetic mean roughness Ra and the average element length Rsm of the base material layer 1 is as follows.

[0036] [Measurement of Arithmetic Mean Roughness Ra and Average Element Length Rsm] For the base layer (polypropylene film) contained in the decorative sheet, the cross-section in the thickness direction of the surface portion facing the glossy pigment layer is observed using a scanning electron microscope, and the arithmetic mean roughness Ra and average element length Rsm are measured. The specific measurement procedure is as follows: 1) Cut out the sample to be measured. 2) Expose the portion to be observed by cross-processing it while cooling using cryo-ion milling. A commercially available cryo-ion milling apparatus is used, and the apparatus conditions are: acceleration voltage 4kV, Ar gas chamber pressure 4.1 × 10⁻⁶ -3 The process is performed using Pa, with a processing time of 12 hours and a cooling temperature of -40°C. The processing area is the substrate layer, with a cross section of 1 mm or more exposed horizontally. 3) Observe the cross section using a scanning electron microscope (SEM). A commercially available scanning electron microscope (SEM) is used for SEM observation, with the following observation conditions: acceleration voltage 3.0 kV, emission current 10 μA, W.D: 8 mm, and observation magnification 2,500x. For the observation area, acquire an image of 40 μm horizontally and 30 μm in the substrate thickness direction, then move to the adjacent area and acquire an image of the same size. Acquire a total of 10 or more images and stitch them together. 4) Record the unevenness of the substrate as a cross-sectional curve from the cross-sectional observation. The measurement area is 300 μm in the direction perpendicular to the thickness (plane direction). To record the cross-sectional curve, set an average line approximately perpendicular to the thickness direction on the image. On the screen, the upper side of the average line represents the convex part, and the lower side represents the concave part. The mean line is defined as the point where the number of concave and convex points on the screen is approximately equal.

[0037] Once the average line is set, taking the direction parallel to the average line as the X-axis, set the left end of the measurement area in the X-axis direction on the screen as the 0 point of X, and the right end of the measurement area as the final point of X (approximately 300 μm, but if the average line is inclined on the screen, it will deviate from 300 μm). Taking the direction perpendicular to the parallel lines as the Y-axis, set the position of the average line as the 0 μm point of the Y-axis. Examine the positional relationship between the average line at the 0 μm point of X and the surface on the side of the light-emitting pigment layer of the substrate. If it is above the average line on the screen (on the side of the light-emitting pigment layer in the thickness direction), it is "+", and if it is below, it is "-". Record the Y-axis position of the surface on the side of the light-emitting pigment layer of the substrate at the 0 point of X, and then record the relationship between X and Y in an electronic spreadsheet such as Excel. Record X at intervals of 0.5 μm. When calculating Ra, use the following formula. Ra = 1 / l ∫Y(X)dx

[0038] Here, l: reference length 300 μm, Y(X): absolute value of Y at the X point, dx: 0.5 μm. When calculating Rsm, use the following formula. Rsm = 1 / m ΣXsi

[0039] m is the number of sets of valleys, with one adjacent valley set as one set, and Xsi is the size in the X-axis direction of one set of valleys constituting the contour element. In this case, as the mountains (valleys) constituting the contour element, those with a height (in the Y-axis direction) of 10% or less of the maximum height or a length (in the X-axis direction) of 1% or less of the length of the calculation section (for example, 3 μm or less when the calculation section is 300 μm) are regarded as noise and recognized as part of the subsequent valleys (mountains).

[0040] The arithmetic mean roughness Ra and the average length of elements Rsm of the substrate layer 1 can be adjusted by means such as adjusting the surface state of the cooling (chill) roll and nip roll, the nip roll pressing load, the melting temperature of the molten resin, and the film conveying speed in the T-die casting method for manufacturing the substrate layer 1. In particular, changing the surface state of the nip roll and cooling roll that the high-temperature film coming out of the T-die first contacts directly determines the surface state of the film. The nip roll is often a rubber roll or a metal roll. When making the surface state flatter, a highly mirror-finished metal roll is used.

[0041] When the substrate layer 1 is observed with a scanning electron microscope in the thickness direction of the surface portions on the side of the phosphorescent pigment layer 2 and the opposite side thereof, it is desirable that the arithmetic mean roughness Ra is 0.20 µm or more in the surface portion on at least one side. If the arithmetic mean roughness Ra of the surface portion of either surface of the substrate layer 1 is less than 0.20 µm, in the process of printing a phosphorescent pigment layer, a primer layer, or the like on the surface layer using this substrate layer, when the substrate wound in a roll shape is unwound and sent to the printing unit, a so-called blocking phenomenon occurs where the substrates stick to each other and cannot be sent out. From the viewpoint of stably preventing blocking, the arithmetic mean roughness Ra of either surface of the substrate layer 1 is preferably 0.25 µm or more, more preferably 0.35 µm or more, and a preferable range is about 0.25 to 0.50 µm.

[0042] The substrate layer 1 preferably contains a thermoplastic resin. Specific examples of the thermoplastic resin contained in the substrate layer 1 include acrylonitrile-butadiene-styrene resin (hereinafter sometimes referred to as "ABS resin"), acrylonitrile-styrene-acrylic ester resin (hereinafter sometimes referred to as "ASA resin"), acrylic resin, polyolefins such as polyethylene and polypropylene, polycarbonate, polyvinyl chloride, polyethylene terephthalate (PET), and the like. Among these, ABS resin, polycarbonate, and polyolefin are preferable, and polyolefin is more preferable. Further, the substrate layer 1 may be formed of a single-layer sheet of these resins, or may be formed of a multi-layer sheet of the same or different resins.

[0043] Examples of polyolefins include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymer of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymer of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. Among these, polypropylene is preferred. When polyolefin resins are copolymers, they may be block copolymers or random copolymers. These polyolefin resins may be used individually or in combination of two or more.

[0044] Furthermore, the polyolefin may be a cyclic polyolefin. A cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of olefins that are constituent monomers of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, isoprene, and the like. Examples of cyclic monomers that are constituent monomers of the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene, and the like. Among these, cyclic alkenes are preferred, and norbornene is more preferred.

[0045] The resin forming the base layer 1 may be recycled material. In other words, the base layer 1 may contain recycled material. Examples of recycled resins include recycled thermoplastic resins (ABS resin, ASA resin, acrylic resin, polypropylene, polyolefins such as polypropylene, polycarbonate, polyvinyl chloride, polyethylene terephthalate (PET), etc.) as mentioned above. The base layer 1 may be composed solely of recycled material, or it may be composed of a mixture of recycled material and virgin material. Recycled resin refers to resin that has been recovered, isolated, and purified from various products used in the market or waste generated from the manufacturing process to make it reusable. Virgin resin material refers to materials that are not recycled, such as new synthetic resins synthesized from new raw materials.

[0046] The base layer 1 may be subjected to physical or chemical surface treatments, such as oxidation or embossing, on one or both sides as necessary to improve adhesion with the layer provided thereon. Examples of oxidation methods used for surface treatment of the base layer 1 include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, and ozone ultraviolet treatment. Examples of embossing methods used for surface treatment of the base layer 1 include sandblasting and solvent treatment. These surface treatments are appropriately selected depending on the resin components constituting the base layer 1, but corona discharge treatment is preferred from the viewpoint of effectiveness and ease of operation.

[0047] Furthermore, the base layer 1 may be subjected to treatments such as forming a known adhesive layer.

[0048] Furthermore, the base layer 1 may or may not be colored using a coloring agent. The base layer 1 may also be colorless and transparent, colored and transparent, or semi-transparent. The coloring agent used in the base layer 1 is not particularly limited, but preferably one that does not discolor even at temperatures of 150°C or higher. Specifically, examples include existing dry colors, paste colors, and masterbatch resin compositions. The base layer 1 may also have an uneven surface to provide aesthetic appeal and tactile sensation.

[0049] The total thickness of the base layer 1 is appropriately set according to the application of the decorative sheet, the lamination method used to integrate it with the article, etc., and is preferably 80 μm or more, more preferably 120 μm or more, and preferably 800 μm or less, and more preferably 600 μm or less. Preferred ranges include approximately 80 to 800 μm, approximately 80 to 600 μm, approximately 120 to 800 μm, and approximately 120 to 600 μm.

[0050] If the base layer 1 is a multi-layered structure, a primer layer, adhesive layer, etc., can be provided between the base layer layers for bonding.

[0051] [Glossy Pigment Layer 2] The glossy pigment layer 2 is a layer provided for the purpose of giving the decorative sheet a metallic design, and is a layer containing a glossy pigment. As described above, in the decorative sheet 10 of this disclosure, as long as the glossy pigment layer 2 is visible from the observer's side, the predetermined surface uneven shape of the base layer 1 may be located on the observer's side or on the opposite side when the decorative sheet is applied to decorate an article. That is, in the decorative sheet 10 of this disclosure, the glossy pigment layer 2 may be laminated on the observer's side of the base layer 1 or on the opposite side of the base layer 1 from the observer's side. In the decorative sheet 10 of this disclosure, if the glossy pigment layer 2 is laminated on the opposite side of the base layer 1 from the observer's side, the glossy pigment layer 2 will be visible through the base layer 1 when it is attached to the outer surface of an article such as the exterior of an automobile.

[0052] The lustrous pigment contained in the lustrous pigment layer 2 is one that can be applied to printing technologies such as gravure printing. Examples of lustrous pigments include glass flakes. The glass flakes are not particularly limited as long as they exhibit a lustrous design, but preferably glass flakes coated with at least one of a metal and a metal oxide are used. The metal used to coat the glass flakes is not particularly limited, but examples include metals such as gold, silver, platinum, palladium, nickel, copper, aluminum, chromium, brass, and tin, as well as metal alloys such as Hastelloy and silver-tin alloy. Among these, silver is preferred from the viewpoint of exhibiting high lustrousness. As for metal oxides, titanium oxide is preferred from the viewpoint of exhibiting high lustrousness. The glass used as the base material for the glass flakes is not particularly limited, but preferred examples include silicate glass, acrylic silicate glass, soda-lime glass, and lead glass. Luminous glass flakes can be obtained by coating the surface of a glass substrate with at least one of a metal and a metal oxide, for example, by electroless plating or sputtering. Such lustrous glass flakes can also be obtained commercially. Luminous glass flakes may be used individually or in combination of two or more types. Aluminum flakes can also be given as lustrous materials. Aluminum flakes can be produced by crushing aluminum with a machine and then spreading it, or by peeling off an aluminum coating obtained by attaching aluminum evaporated by heating to a film on plastic, and then crushing the resulting aluminum coating (hereinafter referred to as vapor-deposited aluminum). Vapor-deposited aluminum is preferred.

[0053] The particle size (average particle size (median diameter) D50) of the luminous pigment can be any size that is applicable to printing technologies such as gravure printing, but from the viewpoint of more favorably exhibiting the effects of the present invention, it is preferably 2 μm or more, more preferably 4 μm or more, even more preferably 6 μm or more, and also preferably 50 μm or less, more preferably 35 μm or less, even more preferably 25 μm or less. Preferred ranges include approximately 2 to 50 μm, approximately 2 to 35 μm, approximately 2 to 25 μm, approximately 4 to 50 μm, approximately 4 to 35 μm, approximately 4 to 25 μm, approximately 6 to 50 μm, approximately 6 to 35 μm, and approximately 6 to 25 μm.

[0054] Furthermore, the thickness of the luminous pigment can be any thickness that is applicable to printing technologies such as gravure printing, but from the viewpoint of exhibiting the effects of the present invention more favorably, it is preferably 1.2 μm or less, more preferably 0.8 μm or less, even more preferably 0.4 μm or less, and also preferably 0.01 μm or more, more preferably 0.03 μm or more, even more preferably 0.05 μm or more. Preferred ranges include approximately 0.01 to 1.2 μm, approximately 0.01 to 0.8 μm, approximately 0.01 to 0.4 μm, approximately 0.03 to 1.2 μm, approximately 0.03 to 0.8 μm, approximately 0.03 to 0.4 μm, approximately 0.05 to 1.2 μm, approximately 0.05 to 0.8 μm, and approximately 0.05 to 0.4 μm.

[0055] The aspect ratio (particle size / thickness) of the particle size to thickness of the luminous pigment is preferably 2.0 or higher, more preferably 3.0 or higher, and even more preferably 5.0 or higher, from the viewpoint of even better demonstrating the effects of the present invention. Furthermore, from the viewpoint of stable procurement of the photopigment, it is more preferably 30 or lower, and even more preferably 25 or lower. Preferred ranges include approximately 2.0 to 30, approximately 2.0 to 25, approximately 3.0 to 30, approximately 3.0 to 25, approximately 5.0 to 30, and approximately 5.0 to 25.

[0056] The lustrous pigment layer 2 contains a lustrous pigment to produce a metallic-looking design, and preferably also contains a binder resin.

[0057] The lustrous pigment layer 2 can be formed by printing a lustrous composition that includes, for example, a lustrous pigment, a binder resin, and a solvent, and optionally contains an extender pigment, stabilizer, plasticizer, catalyst, curing agent, etc.

[0058] The content of the lustrous pigment in the lustrous pigment layer 2 is not particularly limited, but is preferably 1 to 50 parts by mass, and more preferably 10 to 30 parts by mass, per 100 parts by mass of the binder resin in the lustrous pigment layer 2.

[0059] The binder resin of the lustrous pigment layer 2 preferably contains a thermoplastic resin, and more preferably is a thermoplastic resin. Examples of thermoplastic resins include thermoplastic acrylic resins, chlorine-based resins, polyurethanes, polyesters, polyamides, butyral resins, polystyrenes, nitrocellulose resins, and cellulose acetate resins, with thermoplastic acrylic resins and chlorine-based resins being particularly preferred, and thermoplastic acrylic resins being even more preferred. These other thermoplastic resins may be used individually or in combination of two or more.

[0060] Examples of thermoplastic acrylic resins include polymethyl (meth)acrylate, polybutyl (meth)acrylate, methyl (meth)acrylate-butyl (meth)acrylate copolymer, and methyl (meth)acrylate-styrene copolymer. The thermoplastic acrylic resin may be used individually or in combination of two or more types.

[0061] When the binder resin contains a thermoplastic acrylic resin, the content of the thermoplastic acrylic resin in the binder resin of the lustrous pigment layer 2 is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass. In other words, it is preferable that the binder resin of the lustrous pigment layer 2 is substantially composed of a thermoplastic acrylic resin.

[0062] The solvent included in the lustrous composition is not particularly limited as long as it uniformly disperses the lustrous pigment and binder resin components within the composition and is suitable for printing, but preferred examples include methyl ethyl ketone, ethyl acetate, and toluene. The solvent may be used alone or in combination of two or more types.

[0063] The thickness of the lustrous pigment layer 2 is not particularly limited, but from the viewpoint of metallic design and printability, it is preferably 0.1 μm to 10 μm, and more preferably 1 μm to 5 μm. The thickness of the lustrous pigment layer 2 is measured by observing the cross-section of the decorative sheet with an optical microscope at a location where no lustrous pigment is present and the surface of the lustrous pigment layer 2 is not raised by the lustrous pigment.

[0064] The lustrous pigment layer 2 is formed, for example, by printing using a lustrous composition. The printing method for forming the lustrous pigment layer 2 is not particularly limited, but examples include gravure printing, offset printing, screen printing, printing by transfer from a transfer sheet, and inkjet printing.

[0065] [Surface protection layer 3] The surface protection layer 3 is a layer provided to protect the surface of the decorative sheet.

[0066] The material constituting the surface protection layer 3 is not particularly limited, as long as it provides a function of protecting the surface of the decorative sheet. Examples include thermoplastic resins, thermosetting resins, and ionizing radiation-curable resins. Among these, from the viewpoint of suitably imparting the function of a surface protection layer to the decorative sheet, it is preferable that the surface protection layer 3 be composed of a cured product of an ionizing radiation-curable resin composition. The surface protection layer 3 may also be composed of a cured product of an ultraviolet radiation-curable resin composition. The ionizing radiation-curable resin used to form the surface protection layer 3 will be described in detail below.

[0067] (Ionizing Radiation Curable Resin) The ionizing radiation curable resin used to form the surface protective layer 3 is a resin that crosslinks and hardens when irradiated with ionizing radiation. Specifically, it is a mixture of at least one of the following: prepolymers, oligomers, and monomers having polymerizable unsaturated bonds or epoxy groups in their molecules. Here, ionizing radiation refers to electromagnetic waves or charged particle beams that have energy quanta capable of polymerizing or crosslinking molecules. Ultraviolet rays (UV) or electron beams (EB) are usually used, but it also includes electromagnetic waves such as X-rays and gamma rays, and charged particle beams such as alpha rays and ion beams. Among ionizing radiation curable resins, electron beam curable resins are suitable for use in forming the surface protective layer 3 because they can be made solvent-free, do not require photopolymerization initiators, and provide stable curing characteristics.

[0068] As the monomer used as an ionizing radiation-curable resin, (meth)acrylate monomers having radically polymerizable unsaturated groups in the molecule are preferred, and among these, polyfunctional (meth)acrylate monomers are preferred. As a polyfunctional (meth)acrylate monomer, any (meth)acrylate monomer having two or more polymerizable unsaturated bonds (bifunctional or more), preferably three or more (trifunctional or more), in the molecule is acceptable. Specifically, polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphate di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, and trimethylol di(meth)acrylate. Examples include ropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl) isocyanurate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and the like. These monomers may be used individually or in combination of two or more.

[0069] Furthermore, as the oligomer used as an ionizing radiation-curable resin, (meth)acrylate oligomers having radically polymerizable unsaturated groups in the molecule are preferred, and among these, polyfunctional (meth)acrylate oligomers having two or more polymerizable unsaturated bonds (bifunctional or more) in the molecule are preferred. Examples of polyfunctional (meth)acrylate oligomers include polycarbonate (meth)acrylate, acrylic silicone (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, polybutadiene (meth)acrylate, silicone (meth)acrylate, and oligomers having cationic polymerizable functional groups in the molecule (e.g., novolac-type epoxy resin, bisphenol-type epoxy resin, aliphatic vinyl ether, aromatic vinyl ether, etc.). Here, the polycarbonate (meth)acrylate is not particularly limited as long as it has a carbonate bond in the polymer main chain and a (meth)acrylate group in the terminal or side chain, and can be obtained, for example, by esterifying a polycarbonate polyol with (meth)acrylic acid. The polycarbonate (meth)acrylate may also be, for example, a urethane (meth)acrylate having a polycarbonate skeleton. A urethane (meth)acrylate having a polycarbonate skeleton can be obtained, for example, by reacting a polycarbonate polyol with a polyvalent isocyanate compound and a hydroxy(meth)acrylate. Acrylic silicone (meth)acrylate can be obtained by radical copolymerizing a silicone macromonomer with a (meth)acrylate monomer. A urethane (meth)acrylate can be obtained, for example, by esterifying a polyurethane oligomer obtained by reacting a polyether polyol or polyester polyol with a polyisocyanate compound with (meth)acrylic acid. Epoxy (meth)acrylates can be obtained, for example, by reacting (meth)acrylic acid with the oxirane ring of a relatively low molecular weight bisphenol-type epoxy resin or novolac-type epoxy resin to esterify it.Furthermore, carboxyl-modified epoxy (meth)acrylates, obtained by partially modifying this epoxy (meth)acrylate with a dibasic carboxylic acid anhydride, can also be used. Polyester (meth)acrylates can be obtained, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends, obtained by condensation of a polycarboxylic acid and a polyhydric alcohol, with (meth)acrylic acid, or by esterifying the terminal hydroxyl groups of an oligomer obtained by adding an alkylene oxide to a polycarboxylic acid with (meth)acrylic acid. Polyether (meth)acrylates can be obtained by esterifying the hydroxyl groups of a polyether polyol with (meth)acrylic acid. Polybutadiene (meth)acrylates can be obtained by adding (meth)acrylic acid to the side chain of a polybutadiene oligomer. Silicone (meth)acrylates can be obtained by adding (meth)acrylic acid to the end or side chain of a silicone having a polysiloxane bond in its main chain. These oligomers may be used individually or in combination of two or more.

[0070] Among the ionizing radiation-curable resins described above, polycarbonate (meth)acrylate is preferred from the viewpoint of improving aesthetic design, as well as abrasion resistance and moldability. It is also preferable to use a combination of polycarbonate (meth)acrylate and urethane (meth)acrylate.

[0071] Furthermore, the surface protection layer 3 may contain at least one of inorganic particles and organic particles. In the surface protection layer 3, the inorganic particles and organic particles mainly have the function of reducing the gloss of the surface protection layer 3 (making it matte). When the surface protection layer 3 contains inorganic particles or organic particles, these particles are dispersed in the surface protection layer 3. The surface protection layer 3 may be matted by dispersing particles inside the surface protection layer 3, or by having particles present on the surface portion of the surface protection layer 3. When the surface protection layer 3 is matted, the entire surface protection layer 3 may be matted, or it may be partially matted with some parts remaining glossy.

[0072] The inorganic particles are not particularly limited as long as they are particles formed from inorganic compounds, and examples include silica particles, calcium carbonate particles, barium sulfate particles, alumina particles, and glass balloon particles. One type of inorganic particle may be used alone, or two or more types may be used in combination. The particle size of the inorganic particles is, for example, about 0.5 μm or more, preferably about 1 μm or more, and preferably about 20 μm or less, more preferably about 10 μm or less. Preferred ranges for the particle size of the inorganic particles include about 0.5 to 20 μm, about 0.5 to 10 μm, about 1 to 20 μm, and about 1 to 10 μm. The primary particle size of the inorganic particles is preferably 0.001 μm or more, more preferably 0.01 μm or more, even more preferably 0.02 μm or more, even more preferably 0.03 μm or more, and also preferably 3 μm or less, more preferably 2 μm or less, and may include particles in the preferred range of about 0.001 to 3 μm and about 0.01 to 2 μm. In this invention, the particle size of the inorganic particles is the average value of the particle sizes of any 30 inorganic particles observed when the cross-section of the surface protective layer 3 is observed with an SEM (scanning electron microscope). The primary particle size of the inorganic particles is preferably 0.001 μm or more, more preferably 0.01 μm or more, even more preferably 0.02 μm or more, even more preferably 0.03 μm or more, and also preferably 3 μm or less, more preferably 2 μm or less, and a preferred range is approximately 0.001 to 3 μm, and particles of approximately 0.01 to 2 μm may be included.

[0073] When the surface protective layer 3 contains inorganic particles, the amount of inorganic particles is not particularly limited, but is preferably about 1 part by mass or more, more preferably about 10 parts by mass or more, and also preferably about 60 parts by mass or less, and more preferably about 40 parts by mass or less, per 100 parts by mass of the ionizing radiation-curable resin. Preferred ranges for the amount of inorganic particles include about 1 to 60 parts by mass, about 1 to 40 parts by mass, about 10 to 60 parts by mass, and about 10 to 40 parts by mass, per 100 parts by mass of the ionizing radiation-curable resin. One type of inorganic particle may be used alone, or two or more types may be used in combination.

[0074] Furthermore, the organic particles are not particularly limited as long as they are particles formed from resin, and examples include urethane beads, nylon beads, acrylic beads, silicone beads, styrene beads, melamine beads, urethane acrylic beads, polyester beads, polyethylene beads, etc. The organic particles may be used individually or in combination of two or more types. The particle size of the organic particles is about 0.5 μm or more, preferably about 1 μm or more, and preferably about 30 μm or less, more preferably about 20 μm or less. Preferred ranges for the particle size of the organic particles include about 0.5 to 30 μm, about 0.5 to 20 μm, about 1 to 30 μm, and about 1 to 20 μm. The particle size of the organic particles is measured by the same method as for the inorganic particles described above.

[0075] When the surface protective layer 3 contains organic particles, the content of the organic particles is not particularly limited, but is preferably about 1 part by mass or more, more preferably about 10 parts by mass or more, and also preferably about 200 parts by mass or less, and more preferably 150 parts by mass or less, per 100 parts by mass of the ionizing radiation-curable resin. A preferred range for the content of organic particles is about 1 to 200 parts by mass, about 1 to 150 parts by mass, about 10 to 200 parts by mass, and more preferably about 10 to 150 parts by mass, per 100 parts by mass of the ionizing radiation-curable resin.

[0076] Furthermore, if the surface protective layer 3 contains at least one of inorganic particles and organic particles, some of these particles may protrude from the surface of the surface protective layer 3, or the particles may be embedded within the surface protective layer 3.

[0077] (Other additives) Various additives can be added to the surface protective layer 3 depending on the desired physical properties to be provided to the surface protective layer 3. Examples of such additives include weather resistance improvers such as ultraviolet absorbers and light stabilizers, abrasion resistance improvers, polymerization inhibitors, crosslinking agents, infrared absorbers, adhesion improvers, leveling agents, thixotropic agents, coupling agents, plasticizers, defoamers, fillers, solvents, and colorants. These additives can be appropriately selected from those that are commonly used. In addition, reactive ultraviolet absorbers and light stabilizers having polymerizable groups such as (meth)acryloyl groups in their molecules can also be used as ultraviolet absorbers and light stabilizers.

[0078] (Formation of surface protective layer 3) The surface protective layer 3 is formed, for example, by preparing an ionizing radiation-curable resin composition containing an ionizing radiation-curable resin (including, if necessary, the inorganic particles, organic particles, and various additives mentioned above), applying it, and curing it. The viscosity of the ionizing radiation-curable resin composition should be such that it is possible to form an uncured resin layer by the application method described later.

[0079] In this disclosure, the prepared resin composition is applied by known methods such as gravure coating, bar coating, roll coating, reverse roll coating, and comma coating, preferably by gravure coating, to form an uncured resin layer.

[0080] The uncured resin layer formed in this manner is irradiated with ionizing radiation such as electron beams or ultraviolet rays to cure the uncured resin layer and form a surface protective layer 3. When using electron beams as the ionizing radiation, the acceleration voltage can be appropriately selected according to the resin used and the thickness of the layer, but typically the acceleration voltage is 70 kV or more, and 300 kV or less. The preferred range for the acceleration voltage is 70 to 300 kV.

[0081] Furthermore, in electron beam irradiation, the higher the acceleration voltage, the greater the penetration capability. Therefore, when using a resin that is easily degraded by electron beam irradiation beneath the surface protection layer 3, the acceleration voltage should be selected so that the electron beam penetration depth and the thickness of the surface protection layer 3 are substantially equal. This suppresses the irradiation of excess electron beams to the layers located beneath the surface protection layer 3, thereby minimizing the degradation of each layer due to excess electron beams.

[0082] Furthermore, the irradiation dose is preferably the amount at which the crosslinking density of the surface protective layer 3 saturates, and is usually 5 kGy or more (0.5 Mrad or more), preferably 10 kGy or more (1 Mrad or more), and also usually 300 kGy or less (30 Mrad or less), preferably 50 kGy or less (5 Mrad or less). The preferred range of irradiation dose is selected from the ranges of 5 to 300 kGy (0.5 to 30 Mrad), 5 to 50 kGy (0.5 to 5 Mrad), 10 to 300 kGy (1 to 30 Mrad), and 10 to 50 kGy (1 to 5 Mrad).

[0083] Furthermore, there are no particular restrictions on the electron source; for example, various electron beam accelerators such as Cockcroft-Walton type, Van de Graft type, resonant transformer type, insulated core transformer type, linear type, dynamitron type, and high-frequency type can be used.

[0084] When using ultraviolet light as ionizing radiation, it is sufficient to emit light containing ultraviolet light with wavelengths of 190 to 380 nm. There are no particular restrictions on the ultraviolet light source, but examples include high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, and carbon arc lamps.

[0085] The surface protective layer 3 thus formed may be subjected to treatment by adding various additives to impart functions such as hard coating, anti-fogging, anti-staining, anti-glare, anti-reflective coating, ultraviolet shielding, and infrared shielding.

[0086] The thickness of the surface protective layer 3 is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and also preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. Preferred ranges include approximately 1 to 50 μm, approximately 1 to 30 μm, approximately 1 to 20 μm, approximately 3 to 50 μm, approximately 3 to 30 μm, approximately 3 to 20 μm, approximately 5 to 50 μm, approximately 5 to 30 μm, and approximately 5 to 20 μm.

[0087] [First Primer Layer 4] The first primer layer 4 is a layer that is laminated between the substrate layer 1 and the lustrous pigment layer 2 as needed, with the aim of improving the adhesion between them. It is preferable that the first primer layer 4 is in contact with the substrate layer 1 and the lustrous pigment layer 2.

[0088] As described above, in the decorative sheet 10 of this disclosure, even when a first primer layer 4 is laminated between the base layer 1 and the glossy pigment layer 2, if the first primer layer 4 has a surface uneven shape corresponding to the predetermined surface uneven shape of the base layer 1, the glossy pigment layer 2 will be laminated on the surface of the surface uneven shape of the first primer layer 4, and a similarly excellent metallic design will be expressed.

[0089] The primer composition constituting the first primer layer 4 is not particularly limited as long as it can improve adhesion between the substrate layer 1 and the glossy pigment layer 2. Preferably, a primer composition using urethane resin, (meth)acrylic resin, (meth)acrylic-urethane copolymer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, butyral resin, chlorinated polypropylene, chlorinated polyethylene, etc. as a binder resin is used, and one or more of these resins can be used. Among these, urethane resin, (meth)acrylic resin, and (meth)acrylic-urethane copolymer resin are preferred.

[0090] As the urethane resin, polyurethane can be used, with a polyol (polyhydric alcohol) as the main component and an isocyanate as the crosslinking agent (curing agent). The polyol can be one having two or more hydroxyl groups in its molecule, such as polyester polyol, polyethylene glycol, polypropylene glycol, acrylic polyol, or polyether polyol. The isocyanate can be a polyhydric isocyanate having two or more isocyanate groups in its molecule, an aromatic isocyanate such as 4,4-diphenylmethane diisocyanate, or an aliphatic (or alicyclic) isocyanate such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, or hydrogenated diphenylmethane diisocyanate. It is also possible to construct the resin by mixing urethane resin and butyral resin.

[0091] In forming the first primer layer 4, it is preferable to combine an acrylic polyol or polyester polyol as the polyol and hexamethylene diisocyanate or 4,4-diphenylmethane diisocyanate as the crosslinking agent, and it is particularly preferable to use a combination of acrylic polyol and hexamethylene diisocyanate.

[0092] Examples of (meth)acrylic resins include homopolymers of (meth)acrylic acid esters, copolymers of two or more different (meth)acrylic acid ester monomers, or copolymers of (meth)acrylic acid esters with other monomers. Specifically, (meth)acrylic resins consisting of a single or copolymer containing (meth)acrylic acid esters such as polymethyl (meth)acrylate, polyethyl (meth)acrylate, polypropyl (meth)acrylate, polybutyl (meth)acrylate, (methyl)acrylate-butyl (meth)acrylate copolymer, (ethyl)meth)acrylate-butyl (meth)acrylate copolymer, ethylene-methyl (meth)acrylate copolymer, and styrene-methyl (meth)acrylate copolymer are preferably used.

[0093] As the (meth)acrylic-urethane copolymer resin, for example, an acrylic-urethane (polyester urethane) block copolymer resin is preferred. As the curing agent, the above-mentioned various isocyanates can be used. The acrylic-urethane (polyester urethane) block copolymer resin preferably has an acrylic / urethane ratio (mass ratio) of 1 / 9 or more, more preferably 2 / 8 or more. Furthermore, the acrylic / urethane ratio (mass ratio) preferably has a ratio of 9 / 1 or less, more preferably 8 / 2 or less.

[0094] The thickness of the first primer layer 4 is not particularly limited, as long as it achieves the effects of the present invention, but for example it is 0.5 μm or more, preferably 1 μm or more, preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less, with preferred ranges being approximately 0.5 to 15 μm and approximately 1 to 1 μm.

[0095] The first primer layer 4 is formed using a primer composition by conventional coating methods such as gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, reverse roll coating, kiss coating, wheeler coating, dip coating, solid coating by silkscreen, wire bar coating, flow coating, comma coating, pour coating, brush coating, and spray coating, as well as by transfer coating methods. Here, the transfer coating method is a method in which a coating film of the first primer layer 4 is formed on a thin sheet (film substrate), and then coated onto the surface of the target layer in the decorative sheet.

[0096] [Second Primer Layer 5] The second primer layer 5 is a layer that is laminated between the surface protective layer 3 and the layer located beneath it, as needed, for the purpose of improving the adhesion between these layers. The second primer layer 5 is provided so as to be in contact with the surface of the surface protective layer 3 on the substrate layer 1 side.

[0097] The primer composition constituting the second primer layer 5 is not particularly limited as long as it can improve the adhesion between the surface protective layer 3 and the layer located beneath it. Preferably, a primer composition using urethane resin, (meth)acrylic resin, (meth)acrylic-urethane copolymer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, butyral resin, chlorinated polypropylene, chlorinated polyethylene, etc. as a binder resin is used, and one or more of these resins can be used in combination. Among these, urethane resin, (meth)acrylic resin, and (meth)acrylic-urethane copolymer resin are preferred. Specific examples of these resins (urethane resin, (meth)acrylic resin, and (meth)acrylic-urethane copolymer resin) are the same as those exemplified in the first primer layer 4.

[0098] The thickness of the second primer layer 5 is not particularly limited, as long as it achieves the effects of the present invention, but for example it is 0.5 μm or more, preferably 1 μm or more, preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less, with preferred ranges being approximately 0.5 to 15 μm and approximately 1 to 1 μm.

[0099] The second primer layer 5 is formed using a primer composition by conventional application methods such as gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, reverse roll coating, kiss coating, wheeler coating, dip coating, solid coating by silkscreen, wire bar coating, flow coating, comma coating, pour coating, brush coating, and spray coating, as well as by transfer coating methods. Here, the transfer coating method is a method in which a coating film of the second primer layer 5 is formed on a thin sheet (film substrate), and then coated onto the surface of the target layer in the decorative sheet.

[0100] [Adhesive layer 6] The adhesive layer 6 is provided as the outermost layer of the decorative sheet 10 for purposes such as improving the adhesion between the decorative sheet 10 and the article. If the decorative sheet 10 has a surface protection layer 3, the adhesive layer 6 constitutes the surface opposite to the surface protection layer 3.

[0101] For example, a resin composition is used to form the adhesive layer 6.

[0102] Examples of the resin composition include rubber-based resins, acrylic-based resins, epoxy-based resins, and urethane-based resins. Of these, urethane-based resins are preferably used. By using urethane-based resins, stronger adhesive strength can be obtained, and a decorative sheet with excellent flexibility can be provided.

[0103] Urethane resins are polyurethanes that use polyols (polyhydric alcohols) as the main component and isocyanates as crosslinking agents (curing agents).

[0104] Polyols are molecules that have two or more hydroxyl groups in their molecule. Examples of polyols include polyethylene glycol, polypropylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, acrylic polyol, polyester polyol, and polyether polyol.

[0105] In this invention, isocyanates that are commonly used in the production of polyurethanes are also used. Examples of isocyanates include aliphatic polyisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, lysine ester triisocyanate, 1,4,8-triisocyanate octane, 1,3,6-triisocyanate hexane, 2,5,7-trimethyl-1,8-diisocyanate-5-isocyanate methyl octane, and 1,3-cyclopentene diisocyanate. Alicyclic compounds such as anneates, 1,4-cyclohexanediisocyanate, 1,3-cyclohexanediisocyanate, 3-isocyanate-methyl-3,5,5-trimethylcyclohexyl isocyanate (common name: isophorone diisocyanate), 1,3,5-triisocyanate-cyclohexane, 1,3,5-trimethylisocyanate-cyclohexane, and 2-(3-isocyanate-propyl)-2,5-di(isocyanate-methyl)-bicyclo(2,2,1)heptane. Polyisocyanates, 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, aromatic aliphatic polyisocyanates such as 1,3- or 1,4-bis(1-isocyanate-1-methylethyl)benzene and 1,3,5-triisocyanatemethylbenzene, aromatic polyisocyanates such as m-phenylenediisocyanate, p-phenylenediisocyanate, triphenylmethane-4,4',4''-triisocyanate and 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate, and derivatives of these polyisocyanates can be used. Two or more of these polyisocyanates may be used in combination. Among these polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic aliphatic polyisocyanates, and derivatives of these polyisocyanates are preferably used. These polyisocyanates have excellent safety, hygiene, and weather resistance.

[0106] The thickness of the adhesive layer 6 is not particularly limited, but is, for example, 0.5 μm or more, preferably 1 μm or more, and preferably 20 μm or less, more preferably 10 μm or less. Preferred ranges include approximately 0.5 to 20 μm and approximately 1 to 10 μm.

[0107] [Backer Layer] A backer layer may be provided on the side of the decorative sheet opposite to the observer's side. The backer layer generally constitutes one side of the surface of the decorative sheet. The backer layer is a layer provided as needed, for example, to give rigidity to the decorative sheet and maintain its shape.

[0108] The backer layer can be made of, for example, a thermoplastic resin or a paper-based substrate. The thermoplastic resin is not particularly limited, but examples include transparent acrylonitrile-butadiene-styrene resin (sometimes referred to as "ABS resin"), acrylic resin, polyolefin resins such as polypropylene and polyethylene, polycarbonate resin, vinyl chloride resin, polyethylene terephthalate (PET) resin, and acrylonitrile-styrene-acrylic acid ester resin. Among these, the backer layer is preferably made of a polyolefin resin or polyvinyl chloride resin. The resin forming the backer layer may be one type or two or more types.

[0109] The thickness of the backer layer is set appropriately depending on the application of the decorative sheet, the lamination method used to integrate it with the article, etc., and is preferably 80 μm or more, more preferably 120 μm or more, and preferably 800 μm or less, and more preferably 600 μm or less. Preferred ranges include approximately 80 to 800 μm, approximately 80 to 600 μm, approximately 120 to 800 μm, and approximately 120 to 600 μm.

[0110] [Method for Manufacturing Decorative Sheets] The decorative sheet according to this disclosure can be manufactured by a method comprising at least the step of laminating a base layer 1 and a glossy pigment layer 2 to obtain a laminate constituting a decorative sheet. As described above, when the cross-section in the thickness direction of the surface portion on the glossy pigment layer 2 side of the base layer 1 to be laminated is observed with a scanning electron microscope, the maximum height roughness of the elements is 7.0 μm or less, as specified in JIS B0601-2013, and the ratio of the arithmetic mean roughness Ra (μm) to the average length Rsm (μm) of the elements (Ra / Rsm) is 0.040 or less. As described above, as the base layer 1, it is preferable to use one in which the arithmetic mean roughness Ra and the average length Rsm of the elements on the surface have been adjusted as described above by means such as adjusting the surface condition of the cooling (chill) roll and nip roll, adjusting the pressing load of the nip roll, adjusting the melting temperature of the molten resin, and adjusting the film transport speed in the T die-casting method for manufacturing the base layer 1.

[0111] [Articles to which decorative sheets are attached] The decorative sheets of this disclosure can impart an excellent metallic design to the object to which they are attached. The object to which they are attached refers to the article to which the decorative sheet is attached. In recent years, decorative sheets (wrapping sheets) have been increasingly used for decorative purposes on the exteriors of automobiles. Decorative sheets for automobile exteriors are required to express, for example, a metallic design. The decorative sheet 10 of this disclosure can be suitably used, for example, for decorative purposes on the exteriors of automobiles.

[0112] Furthermore, the decorative sheet of this disclosure can be integrated with a molded resin layer and used to manufacture a decorative resin molded product. Also, when the decorative sheet is provided on a molded part by lamination, the material of the molded part may be metal.

[0113] Specifically, the decorative resin molded product of the present disclosure can be manufactured by a method comprising the step of forming a molded resin layer by injecting resin onto the decorative sheet 10 of the present disclosure. For example, the manufacturing method of the decorative resin molded product of the present disclosure comprises the steps of electrostatically charging the decorative sheet of the present disclosure and fixing the decorative sheet to a mold, and integrating the decorative sheet 10 and the molded resin layer 6 by injecting resin into the mold.

[0114] Various injection molding methods can be used to integrate the decorative sheet and the molded resin layer according to this disclosure, including insert molding, cavity process (ICP, see, for example, Japanese Patent No. 7177996), blow molding, and gas injection molding. Among these, insert molding is particularly suitable in this disclosure.

[0115] In the insert molding method, first, in the vacuum forming process, the decorative sheet of this disclosure is vacuum-formed to the surface shape of the molded product using a vacuum forming die (offline pre-forming), and then excess portions are trimmed as needed to obtain a molded sheet. This molded sheet is inserted into an injection molding die, the injection molding die is clamped, and a fluid resin is injected into the mold and solidified, thereby integrating the decorative sheet with the outer surface of the resin molded product at the same time as injection molding, and thus a decorated resin molded product is manufactured.

[0116] More specifically, the decorative resin molded articles of this disclosure are manufactured by an insert molding method that includes the following steps.

[0117] The present disclosure comprises a vacuum forming step of pre-forming a decorative sheet into a three-dimensional shape using a vacuum forming die, a step of trimming excess portions of the vacuum-formed decorative sheet to obtain a molded sheet, and a step of inserting the molded sheet obtained in the above step into an injection molding die (mold), closing the injection molding die, and injecting a fluid resin into the mold to integrate the resin and the molded sheet. In this step, the decorative sheet can be electrostatically charged to fix it to the injection molding die.

[0118] In the vacuum forming step of the insert molding method, the decorative sheet may be heated during the molding process. The heating temperature at this time is not particularly limited and can be appropriately selected depending on the type of resin constituting the decorative sheet and the thickness of the decorative sheet. However, in this disclosure, since the base layer 1 is made of polyolefin, the temperature can be, for example, about 100 to 180°C, preferably about 120 to 160°C. Furthermore, in the integration step, the temperature of the resin in the flow state is not particularly limited, but can usually be about 160 to 240°C, preferably about 180 to 220°C.

[0119] (Production of decorated molded products by in-cavity process) For example, using a ceramic heater or the like as a heat source, the decorative sheet is heated to a temperature of 150°C using a preheated heating plate. The decorative sheet is held in a movable heater and pressed into a tray-shaped mold with a high degree of deep drawing to form it. Meanwhile, polypropylene resin is used as the injection resin, and after being brought to a melted state, it is injected into the cavity to obtain a laminate of the decorative sheet and the injection resin. The obtained laminate is removed from the mold and molded by the in-cavity process to obtain a decorated molded product. Alternatively, an infrared heater may be used as the heat source to hold the film and then emit infrared rays onto the film.

[0120] If the material of the molded part is metal, the decorative molded product may further have an electrodeposited coating film as an undercoat formed between the molded part and the decorative sheet. In this case, the decorative sheet can replace the intermediate and top coats in conventional painting. Also, if the material of the molded part is metal, the decorative molded product may further have a rust-preventive plating layer formed on the surface of the molded part for rust prevention. The rust-preventive plating layer may be, for example, a zinc alloy plating film or an iron-nickel alloy plating film. If the material of the molded part is metal, the molded part may be made by applying the decorative sheet to a molded metal plate. Alternatively, if the material of the molded part is metal, the molded part may be made by applying the decorative sheet to a metal plate to make a laminated metal plate, and then molding the laminated metal plate.

[0121] The decorative sheets disclosed herein can be applied not only to automobile bodies, but also to interior or exterior (exterior) cover materials for vehicles such as railway cars, ships, and aircraft, as well as panel materials for various signs and outdoor advertisements, and to objects to be laminated, such as building wall materials (exterior and interior materials), partitions, doors, window frames and other fixtures, desks, dining tables, cupboards, counter tables, sinks, furniture, and interior decorations. In particular, because they can be easily positioned and laminated even to large-area objects, they are suitable for use on the exteriors of vehicles.

[0122] An article to which the decorative sheet of this disclosure is attached is formed by integrating the decorative sheet 10 of this disclosure with the article. That is, an article to which the decorative sheet of this disclosure is attached is a decorative article (including a decorative molded article) to which the decorative sheet of this disclosure is attached to the outer surface of the article. For example, a decorative article to which the decorative sheet of this disclosure is attached to the outer surface of an automobile is an automobile to which the decorative sheet of this disclosure is attached to the body of an automobile.

[0123] The present disclosure will be described in detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the examples.

[0124] [Manufacturing of Decorative Sheets] <Example 1> A decorative sheet was manufactured by sequentially laminating a first primer layer (2 μm thick urethane resin formed from acrylic polyol and isocyanate curing agent), a lustrous pigment layer (4 μm thick resin composition for forming lustrous pigments containing acrylic polymer and aluminum flakes (average particle size (median diameter) D50 12 μm, thickness 0.2 μm)) on one side of a polypropylene film (PP, 100 μm thick) as a base layer using gravure printing, and a second primer layer (2 μm thick urethane resin formed from acrylic polyol and isocyanate curing agent), and a surface protection layer (10 μm thick UV-curable urethane acrylate). The laminated structure was such that the base layer, first primer layer, lustrous pigment layer, second primer layer, and surface protection layer were laminated in this order. For the surface protection layer, UV-curable urethane acrylate was applied by gravure coating to a thickness of 10 μm after curing to form an uncured resin layer. This uncured resin layer was then cured by UV irradiation to form the surface protection layer.

[0125] In Example 1, the polypropylene film used as the base layer had the arithmetic mean roughness Ra (μm) and average element length Rsm (μm) values ​​shown in Table 1 when the cross-section in the thickness direction of the surface portion on the luminous pigment layer side was observed with a scanning electron microscope. The arithmetic mean roughness Ra (μm) and average element length Rsm (μm) of the surface portion of the base layer were adjusted by the surface condition of the roll and the nip pressure in a T-die casting method using a metal nip roll.

[0126] <Examples 2-3 and Comparative Examples 1-3> Decorative sheets were manufactured in the same manner as in Example 1, except that a polypropylene film with the arithmetic mean roughness Ra (μm) and average element length Rsm (mm) listed in Table 1 was used as the base layer (when the cross-section in the thickness direction of the surface portion on the lustrous pigment layer side was observed with a scanning electron microscope, the arithmetic mean roughness Ra (μm) and average element length Rsm (μm) were the values ​​listed in Table 1). The arithmetic mean roughness Ra (μm) and average element length Rsm (μm) of the surface portion of the base layer were adjusted by the surface condition of the roll and the nip pressure in a T-die casting method using a metal nip roll or a rubber roll, respectively.

[0127] <Example 4> On one side of a polypropylene film (PP, 100 μm thick) used as a base layer, a first primer layer (2 μm thick urethane resin formed from acrylic polyol and isocyanate curing agent), a glossy pigment layer (4 μm thick resin composition for forming glossy pigment containing acrylic polymer and aluminum flakes (size average particle size (median diameter) D50 12 μm, thickness 0.2 μm)) and an adhesive layer (1.5 μm thick acrylic polymer) were sequentially laminated by gravure printing. On the other side of the base layer, a second primer layer (2 μm thick urethane resin formed from acrylic polyol and isocyanate curing agent) and a surface protection layer (10 μm thick UV-curable urethane acrylate) were sequentially laminated to produce a decorative sheet having a laminated structure in which the adhesive layer, glossy pigment layer, first primer layer, base layer, second primer layer, and surface protection layer were laminated in this order. For the surface protection layer, UV-curable urethane acrylate was applied by gravure coating to a thickness of 10 μm after curing to form an uncured resin layer. This uncured resin layer was then cured by UV irradiation to form the surface protection layer.

[0128] In Example 4, the polypropylene film used as the base layer, when observed with a scanning electron microscope in the thickness direction of the surface portion on the luminous pigment layer side, had the arithmetic mean roughness Ra (μm) and average element length Rsm (mm) specified in JIS B0601-2013, respectively, as shown in Table 2. The arithmetic mean roughness Ra (μm) and average element length Rsm (μm) of the surface portion of the base layer were adjusted by the surface condition of the roll and the nip pressure in a T-die casting method using a metal nip roll.

[0129] <Examples 5-6 and Comparative Example 4> Decorative sheets were manufactured in the same manner as in Example 4, except that a polypropylene film with the arithmetic mean roughness Ra (μm) and average element length Rsm (mm) listed in Table 2 was used as the base layer (when the cross-section in the thickness direction of the surface portion on the lustrous pigment layer side was observed with a scanning electron microscope, the arithmetic mean roughness Ra (μm) and average element length Rsm (μm) specified in JIS B0601-2013 were, respectively, the values ​​listed in Table 2). The arithmetic mean roughness Ra (μm) and average element length Rsm (mm) of the surface portion of the base layer were adjusted by the surface condition of the roll and the nip pressure in a T-die casting method using a metal nip roll or a rubber roll, respectively.

[0130] [Measurement of Arithmetic Mean Roughness Ra and Average Element Length Rsm] For the base layer (polypropylene film) contained in the decorative sheet, the cross-section in the thickness direction of the surface portion facing the glossy pigment layer was observed using a scanning electron microscope, and the maximum element height roughness Rz (μm), the average element length Rsm, and the arithmetic mean roughness Ra were measured as specified in JIS B0601-2013. In addition, the arithmetic mean roughness Ra' was measured on the side opposite to the glossy pigment layer (the back side). The specific measurement procedure is as follows. The results are shown in Tables 1 and 2.

[0131] [Evaluation of the metallic appearance of decorative sheets] The metallic appearance of the decorative sheets was evaluated from the observer's side (surface protective layer side). In evaluating the metallic appearance, visual evaluation and, as a reference value, evaluation using a colorimeter were performed. Visual evaluation was performed using the standard light source D defined by the International Commission on Illumination (CIE). 65 The evaluation was conducted in a room with a lamp installed on the ceiling. For specular reflection evaluation, the object was held at eye level, with its surface at a 45° angle to the ground. For evaluations other than specular reflection, the object was fixed to a table or similar object at a position lower than eye level. The surface of the object was viewed from a 45° angle to the ground. For metallic appearance evaluation, the brightness observed under specular reflection, and the difference in brightness between specular and non-specular reflection were checked. The larger both of these differences, the better the metallic appearance.

[0132] The evaluation by the colorimeter adopts the evaluation by a light source with single-direction irradiation (45° direction) and two-angle light reception (multi-angle measurement at two angles of 15° and 45° as viewed from the specular reflection light). The specific evaluation conditions are as follows. - Equipment: X-Rite MA68 II - Optical system: 45° illumination, observation angles of 15° and 45° - Measurement wavelength range: 400 - 700 nm - Observation light source: D 65 - Light-receiving element: Blue-enhanced silicon photodiode - Measurement item: Luminance L * Value (JIS Z 8781-4) Here, the observation angle of 15° is used to evaluate the brightness as a metallic tone near the specular reflection. The observation angle of 45° measures the luminance at a typical angle other than the specular reflection. The angular dependence of the luminance, which is one of the characteristics of the metal, is evaluated as the difference between the L * value at the observation angle of 15° and the L * value at the observation angle of 45°. The larger the value, the more it is judged to have the characteristics as a metallic tone.

[0133] (Evaluation criteria for metallic tone designs) Here, the observation angle of 15° is used to evaluate the brightness as a metallic tone near the specular reflection. The observation angle of 45° measures the luminance at a typical angle other than the specular reflection. The angular dependence of the luminance, which is one of the characteristics of the metal, is evaluated as the difference between the L * value at the observation angle of 15° and the L * value at the observation angle of 45°. The larger the value, the more it is judged to have the characteristics as a metallic tone.

[0134] (Evaluation criteria for metallic tone designs by visual inspection) A: It is bright enough to be dazzling at specular reflection and appears dark at the other observation angle. B: It is bright at specular reflection and appears slightly dark at the other observation angle. C: It is slightly bright at specular reflection and is slightly bright at the other observation angle.

[0135] [Processing handling property] For the polypropylene films used as the base material layers in the examples and comparative examples, the processing handling properties were evaluated by the following procedure 1) and procedure 2), respectively. The results are shown in Tables 1 and 2. Procedure 1) Stack two polypropylene films, place a weight with a diameter of 3 cm on the upper part of the stacked polypropylene films, and apply a pressure of 1.5 kg / cm 2Apply pressure. Leave in a 25°C environment for 24 hours. Step 2) After 24 hours, remove the weight and peel the two polypropylene films apart by hand. Check the resistance at this time. If there is resistance when peeling, it means that the polypropylene film cannot be fed out for printing, or that part of the polypropylene film stretches and becomes loose when peeled off with too much force.

[0136] (Evaluation criteria for processing and handling ease) A: Peels off without resistance. C: There is resistance when peeling.

[0137]

[0138]

[0139] 1. Substrate layer 2. Luminous pigment layer 3. Surface protective layer 4. First primer layer 5. Second primer layer 6. Adhesive layer 10. Decorative sheet

Claims

1. A decorative sheet comprising at least a base layer and a glossy pigment layer, wherein, when the cross-section in the thickness direction of the surface portion on the glossy pigment layer side of the base layer is observed with a scanning electron microscope, the maximum height roughness Rz (μm) of the elements as defined in JIS B0601-2013 is 7.0 μm or less, and the ratio of the arithmetic mean roughness Ra (μm) to the average length Rsm (μm) of the elements (Ra / Rsm) is 0.040 or less.

2. The decorative sheet according to claim 1, wherein when the cross-section in the thickness direction of the surface portion on the side of the lustrous pigment layer and the opposite side of the substrate layer is observed with a scanning electron microscope, at least one of the surface portions has an arithmetic mean roughness Ra of 0.25 μm or more.

3. The decorative sheet according to claim 1 or 2, further comprising a first primer layer between the base material layer and the lustrous pigment layer.

4. The decorative sheet according to claim 1 or 2, further comprising a surface protective layer.

5. The decorative sheet according to claim 4, further comprising a second primer layer in contact with the surface of the surface protective layer on the substrate layer side.

6. The decorative sheet according to claim 1 or 2, further comprising an adhesive layer as the outermost layer.

7. The decorative sheet according to claim 1 or 2, for use on the exterior of an automobile.

8. A method for manufacturing a decorative sheet, comprising at least a base layer and a glossy pigment layer, the method comprising at least a step of laminating the base layer and the glossy pigment layer to obtain a laminate constituting the decorative sheet, wherein, when the cross-section in the thickness direction of the surface portion on the glossy pigment layer side of the base layer is observed with a scanning electron microscope, the maximum height roughness of the elements as defined in JIS B0601-2013 is 7.0 μm or less, and the ratio of the numerical value of the arithmetic mean roughness Ra (μm) to the numerical value of the numerical value of the average length Rsm (μm) of the elements (Ra / Rsm) is 0.040 or less.

9. A decorated article having the decorative sheet described in claim 1 or 2 attached to the outer surface of the article.

10. An automobile having the decorative sheet described in claim 1 or 2 attached to the body of the automobile.

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