Decorative sheet and manufacturing method thereof

Abstract

To provide a decorative sheet that can avoid increase in the amount of addition of an inorganic pigment, has excellent flexibility such as bending workability, and excellent concealability, and a method for producing the same.SOLUTION: A decorative sheet 1 according to an embodiment has at least a white sheet 2 and a pattern layer 5, which are stacked in the stated order. The pattern layer 5 contains at least one blue pigment. A spectrophotometric reflectance measured from the pattern layer 5 side has a minimum value in a wavelength range of 500 nm or more and 650 nm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a decorative sheet and a method for producing the same. [Background technology]

[0002] In recent years, many decorative sheets using olefin resins (e.g., polypropylene sheets) have been proposed as alternatives to decorative sheets made of polyvinyl chloride, which are environmentally hazardous. Patent Document 1, for example, describes a technology relating to decorative sheets using olefin resins. These decorative sheets do not use vinyl chloride resin, which reduces the generation of toxic gases when incinerated. However, polypropylene sheets generally have poor scratch resistance due to their low elastic modulus, and they tend to stretch when tension is applied to the sheet during sheet preparation for printing, etc.

[0003] Decorative sheets become decorative boards by being attached to the surface of a substrate such as a wood substrate, a metal substrate, or a non-flammable substrate, and the decorative sheet imparts a design to the decorative board according to the purpose. Therefore, the decorative sheet must completely conceal the surface of the substrate as needed. In this case, a decorative sheet that is colored with at least a pigment and has concealing properties must be used. The simplest decorative sheet configuration is one consisting of a single colored sheet (single layer). With such single-layer decorative sheets, the designs that can be imparted are usually limited to a single color without a pattern. However, by adding a lustrous material such as aluminum flakes or pearl pigments as a pigment, a lustrous feel can be imparted, making it possible to express the necessary and sufficient design. Furthermore, if a more sophisticated design is desired, it is also effective to decorate the surface of the sheet itself, such as by printing.

[0004] Among decorative sheets, white sheets are used for door frames, baseboards, various storage compartments, etc. The surface of the substrate is easily visible through white sheets, so a large amount of pigment needs to be added to impart hiding properties. However, adding a large amount of pigment causes the entire white sheet to become hard and prone to breaking, which is a problem. For example, Patent Document 2 proposes a decorative sheet that has excellent hiding properties by compounding an inorganic pigment in a vesiculated state and increasing the amount of pigment added. However, the decorative sheet in Patent Document 2 cannot avoid increasing the amount of pigment added, and the problem of the white sheet's reduced bending processability and prone to breaking remains unresolved. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3271022 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-155233 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in light of the above-mentioned problems, and aims to provide a decorative sheet that can avoid an increase in the amount of inorganic pigment added, has excellent flexibility such as bending workability, and has excellent hiding power, and a method for producing the same. [Means for solving the problem]

[0007] The inventors have conducted various studies and experiments and have found that, for example, by adding at least one type of blue pigment to the pattern layer, it is possible to provide a decorative sheet with a minimum value of spectral reflectance in a wavelength region within a specified range and excellent hiding power, as well as a method for manufacturing the same.

[0008] That is, in order to achieve the above object, a decorative sheet according to one aspect of the present invention is a decorative sheet in which at least a white sheet and a pattern layer are laminated in this order, and the pattern layer comprises:As a pigment blue pigment Only or only the blue pigment and titanium dioxide The gist of the invention is that the spectral reflectance measured from the pattern layer side has a minimum value in a wavelength region of 500 nm or more and 650 nm or less, and when the reflected chromaticity is measured from the pattern layer side using a D65 light source, L* in the Lab color system is in the range of +90 or more and +100 or less, a* is in the range of -1.5 or more and +1.5 or less, and b* is in the range of -1.5 or more and +2.0 or less. Further, a method for producing a decorative sheet according to one aspect of the present invention comprises: Only blue pigment as pigment or , the blue pigment and titanium dioxide only By adding to the pattern layer, the colorimeter has a minimum value of spectral reflectance measured from the pattern layer side in a wavelength region of 500 nm or more and 650 nm or less, When the reflected chromaticity is measured from the pattern layer side using a D65 light source, The gist of the present invention is to produce a decorative sheet in which L* in the Lab color system is in the range of +90 or more and +100 or less, a* is in the range of -1.5 or more and +1.5 or less, and b* is in the range of -1.5 or more and +2.0 or less. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to provide a decorative sheet that can avoid an increase in the amount of inorganic pigment added, has excellent flexibility such as bending workability, and has excellent hiding power, and a method for producing the same. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing an example of the structure of a decorative sheet according to an embodiment of the present invention. [Figure 2] A cross-sectional view showing an example of the structure of another decorative sheet according to an embodiment of the present invention. [Figure 3] 1 is a graph showing the spectral reflectance of a white sheet containing only titanium oxide. [Figure 4] 1 is a graph showing the spectral reflectance of decorative sheets containing cobalt blue and ultramarine blue as blue pigments in the design layer. [Figure 5] 1 is a graph showing the spectral reflectance measured for the same white sheet with a white background and a black background. [Figure 6] 1 is a graph showing the spectral reflectance of the decorative sheets of Examples 1-4 and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., differ from the actual ones. Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, shapes, structures, etc. of the components to those described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims.

[0012] "composition" The decorative sheet 1 of the embodiment shown in FIG. 1 is an example produced by laminating a white sheet 2 and a design layer 5. The white sheet 2 of this embodiment has at least a colored layer 3 formed by mixing an inorganic pigment with an olefin-based resin such as polypropylene resin, i.e., a colored layer 3 containing an inorganic pigment and an olefin-based resin such as polypropylene resin. The white sheet 2 may also be composed of the colored layer 3 and a skin layer 4 made of polypropylene resin. The skin layer 4 may be formed on at least one side of the colored layer 3. The skin layer 4 is intended to prevent the inorganic pigment contained in the colored layer 3 from bleeding and adhering to the manufacturing equipment (e.g., an extruder) during the manufacturing process of the decorative sheet 1, resulting in film formation defects. The skin layer 4 may contain a nano-sized nucleating agent to improve the crystallinity of the polypropylene resin. Improving the crystallinity of the polypropylene resin improves scratch resistance. In this embodiment, the nucleating agent may be contained in the form of a nucleating agent vesicle, for example, encapsulated in an outer membrane. Moreover, a pattern layer 5 is formed (laminated) on one surface of the white sheet 2 in order to improve the design of the decorative sheet 1.

[0013] As shown in Fig. 2, the decorative sheet 1 may have a structure in which at least one of a transparent resin layer 6 and a top coat layer 7 is laminated on a design layer 5, i.e., on one side of the design layer 5, as needed. The decorative sheet 1 illustrated in Fig. 2 is an example in which a design layer 5, a transparent resin layer 6, and a top coat layer 7 are laminated in this order on one side of a white sheet 2. Alternatively, either the transparent resin layer 6 or the top coat layer 7 may be omitted.

[0014] Depending on the design requirements, at least one of the transparent resin layer 6 and the top coat layer 7 may be provided with an embossed pattern (embossed pattern 6a). Ink may be embedded in the embossed pattern 6a to further enhance the design. Furthermore, if there are problems with the adhesion between the design layer 5 and the transparent resin layer 6, an adhesive resin layer 6b may be provided as needed to improve the adhesion between the design layer 5 and the transparent resin layer 6. When the adhesive resin layer 6b is provided, it may be formed by co-extrusion of the transparent resin layer 6 and the adhesive resin layer 6b. The adhesive resin layer 6b may be formed from, for example, an acid-modified resin such as polypropylene, polyethylene, or acrylic resin. The thickness of the adhesive resin layer 6b is preferably 2 μm or more to improve adhesive strength. Furthermore, to meet requirements such as scratch resistance, at least one of the transparent resin layer 6 and the top coat layer 7 may be laminated in multiple layers. The decorative sheet 1 according to this embodiment may also be configured to include other known layers.

[0015] 1 and 2, the symbol B represents a substrate. The substrate B is a substrate to which the decorative sheet 1 is attached. There are no particular limitations on the substrate B, but examples include composite boards formed from multiple materials such as wood boards, inorganic boards, and metal plates. A primer layer 8 or a concealing layer (not shown) may be provided between the decorative sheet 1 and the substrate B as appropriate.

[0016] The tensile modulus of the decorative sheet 1 of this embodiment, particularly the tensile modulus of the white sheet 2 alone, is preferably in the range of 1000 MPa to 2200 MPa. If the tensile modulus is less than 1000 MPa, scratch resistance tends to be poor. Furthermore, if the tensile modulus exceeds 2200 MPa, the crystallinity is too high, and even when a nucleating agent (e.g., nucleating agent vesicles) is used, problems such as whitening and cracking may occur during bending.

[0017] Next, each layer that constitutes the decorative sheet 1 will be described.

[0018] <White sheet> The white sheet 2 has a colored layer 3 formed by, for example, mixing an inorganic pigment in a resin at an appropriate ratio. If the colored layer 3 is the outermost layer, the pigment component contained in the colored layer 3 may bleed and contaminate the T-die of the extruder or the rolls during transport, so it is desirable to provide skin layers 4 on both sides of the colored layer 3. If the skin layer 4 is thin, the pigment component contained in the colored layer 3 will bleed, so the thickness of the skin layer 4 is preferably within the range of 3 μm to 20 μm. Note that if the purpose is to improve scratch resistance, the skin layer 4 may be formed on at least one side of the colored layer 3.

[0019] (inorganic pigments) The inorganic pigment contains, for example, titanium oxide, to impart hiding properties to the white sheet 2. The white sheet 2 serves to conceal the pattern on the substrate B. To obtain the hiding properties required from the standpoint of the design of the decorative sheet 1, the light transmittance of the white sheet 2 is preferably 40% or less. If the hiding properties of the white sheet 2 are low, the pattern on the substrate B will be visible through the white sheet 2. This results in the pattern of the picture layer 5 and the pattern of the substrate B being mixed together in the decorative sheet 1, which is undesirable. By incorporating an inorganic pigment into the colored layer 3 that constitutes the white sheet 2, a decorative sheet 1 with good hiding properties can be obtained. The total amount (addition amount) of the inorganic pigment in the colored layer 3 is preferably within the range of 5 to 70 parts by mass, based on 100 parts by mass of the resin material. If the amount of inorganic pigment mixed is less than 5 parts by mass, the hiding properties of the white sheet 2 will be poor, and if the amount of inorganic pigment mixed is more than 70 parts by mass, the white sheet 2 will become embrittled, which is undesirable. Fig. 3 shows a graph of the spectral reflectance of a white sheet 2 containing only titanium oxide as the inorganic pigment in the colored layer 3. As shown in Fig. 3, the white sheet 2 has low spectral reflectance for light on the short wavelength side (here, wavelengths less than 450 nm), but shows a spectral reflectance of 90% or more in the wavelength range of 450 nm or more and 700 nm or less.

[0020] In this embodiment, the spectral reflectance was measured using a fluorescence spectrodensitometer (FD-7) manufactured by Konica Minolta, Inc., and the spectral reflectance was measured in the wavelength range of 400 nm to 700 nm. In addition, taking into consideration the influence of the color of the base, an opacity test paper ( Spectral reflectance was measured on a white background (Byko-Chart high brightness 2A).

[0021] The inorganic pigment contained in the colored layer 3 of the white sheet 2 may be other than the above-mentioned titanium oxide. For example, known inorganic pigments can be mixed and used as the inorganic pigment. The inorganic pigment to be mixed is not particularly limited, but examples thereof include natural inorganic pigments and synthetic inorganic pigments. Examples of natural inorganic pigments include earth pigments, calcined earth, and mineral pigments. Examples of synthetic inorganic pigments include oxide pigments, hydroxide pigments, sulfide pigments, silicate pigments, phosphate pigments, carbonate pigments, metal powder pigments, and carbon pigments. Also, a mixed pigment containing one or more natural and synthetic inorganic pigments may be used. Furthermore, organic pigments such as phthalocyanine and carbon black may be used in combination in the colored layer 3.

[0022] (resin) From an environmental perspective, the resin mixed with the inorganic pigment in the colored layer 3 of the white sheet 2 is preferably an olefin-based resin. Examples of olefin-based resins include olefin homopolymers such as ethylene, propylene, and butene; ethylene-propylene block copolymers; and random copolymers. Other examples of olefin-based resins include copolymers of at least one of ethylene and propylene with at least one other olefin such as butene, pentene, and hexene; and copolymers of at least one of ethylene and propylene with at least one other monomer such as vinyl acetate or vinyl alcohol. Among these, polyethylene and polypropylene are preferred for the resin used in the colored layer 3 from the viewpoint of achieving excellent scratch resistance and good bending processability. In other words, in this embodiment, the white sheet 2 is preferably primarily composed of polyethylene and titanium oxide, or primarily composed of polypropylene and titanium oxide. Here, unless otherwise specified, the term "main component" in this embodiment refers to 90% by mass or more of the target material.

[0023] [Polyethylene resin] The polyethylene mixed with the inorganic pigment in the colored layer 3 may be a homopolymer of ethylene, or a copolymer of ethylene and another comonomer copolymerizable with ethylene (e.g., propylene, The polyethylene resin may be a copolymer with an α-olefin such as 1-butene, 1-hexene, or 1-octene, vinyl acetate, or vinyl alcohol. Examples of such polyethylene include ethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), ultra-high molecular weight polyethylene (UHMWPE), cross-linked polyethylene (PEX), etc. These polyethylenes may be used alone or in combination of two or more.

[0024] [Polypropylene resin] It is preferable to use the highly crystalline polypropylene described below as the polypropylene resin to be mixed with the inorganic pigment in the colored layer 3, but it is also possible to mix the highly crystalline homopolypropylene with, for example, a random polypropylene resin having an ethylene content within a specified range or a known amorphous polypropylene resin.

[0025] In this embodiment, it is preferable to use a highly crystalline polypropylene resin as the polypropylene resin to be mixed with the inorganic pigment. In particular, it is preferable to use a highly crystalline homopolypropylene resin, which is a propylene homopolymer having an isotactic pentad fraction (mmmm fraction) of 95% or more, in an amount of 50% by mass to 100% by mass based on the mass of the total polypropylene resin.

[0026] The crystallization temperature of polypropylene resin is generally in the range of 100°C to 130°C, and when a nucleating agent is added, it is in the range of 110°C to 140°C. Furthermore, when a polypropylene resin with an isotactic pentad fraction (mmmm fraction) of less than 95% is used, the crystallinity is insufficient. Therefore, even if the manufacturing process is controlled, the tensile modulus may be lower than the preferred range. Similarly, when the highly crystalline homopolypropylene resin is less than 50% by mass, the crystallinity is insufficient. Therefore, even if the manufacturing process is controlled, the tensile modulus may be lower than the preferred range.

[0027] Here, the isotactic pentad fraction (mmmm fraction) is calculated from the numerical value (electromagnetic wave absorption rate) obtained by resonating a resin material at a predetermined resonance frequency using 13C-NMR (nuclear magnetic resonance) measurement using carbon (C) with a mass of 13. This value defines the atomic arrangement, electronic structure, and molecular microstructure of the resin material. The pentad fraction of a crystalline polypropylene resin is the ratio of five propylene units arranged in a row as determined by 13C-NMR and is used as a measure of crystallinity or stereoregularity. The pentad fraction is one of the important factors that primarily determine the scratch resistance of a surface; generally, a higher pentad fraction indicates a higher degree of crystallinity.

[0028] In the decorative sheet 1, when the white sheet 2 is formed from a resin such as an olefin-based resin and has an inactive surface, it is desirable to subject both the front and back surfaces of the white sheet 2 to, for example, corona treatment, plasma treatment, ozone treatment, electron beam treatment, ultraviolet treatment, dichromate treatment, etc.

[0029] Furthermore, additives such as fatty acid metal salts may be added to resins such as polypropylene resins in order to improve dispersibility and extrudability.

[0030] <Picture layer 5> A pattern layer 5 can be provided on the surface of the white sheet 2 to add a pattern to the decorative sheet 1. Examples of patterns that can be used include wood grain, stone grain, sand grain, tiled, brickwork, fabric grain, leather-striped patterns, and geometric shapes.

[0031] The pattern layer 5 contains at least one type of blue pigment. Powdered lapis lazuli was used as a deep blue-purple pigment. It was called ultramarine because it was brought from far across the ocean. Nowadays, ultramarine can be synthesized and is known as ultramarine. Ultramarine can be made, for example, by mixing the clay mineral kaolin with sulfur, activated carbon, etc., and baking the mixture. The three-dimensional aluminosilicate lattice that makes up ultramarine contains three sulfur atoms that are bonded to form ions. The blue color of the pigment is due to a radical anion with an unpaired electron, and it is vulnerable to acids. Ultramarine can also be made by mixing, for example, a sulfur-containing sodium silicate complex (Na 8-10 Al6Si6O 24 S 2-4 ) is available.

[0032] Furthermore, Prussian blue (Millory blue) is the first synthetic pigment developed in Germany and is also known as Prussian blue. Another bright blue pigment is cobalt blue. Other than these, inorganic pigments such as cerulean blue and gosu (underground blue) can be used as blue pigments. Prussian blue (Millory blue) is a pigment represented by the composition formula Fe4[Fe(CN)6]3, for example. Cobalt blue is a pigment represented by the composition formula CoAl2O4 or CoOAl2O3, for example. Cerulean blue is a pigment represented by the composition formula CoO·nSnO2·mMgO (n=1.5-3.5, m=2-6), for example. Gosu is, for example, quartz, halloysite, and lithiopholite. The decorative sheet 1 according to this embodiment uses ultramarine (ultramarine blue) as a blue pigment. Marine), Prussian Blue (Milory Blue), Cobalt Blue, Cerulean Blue, and Gosu It is sufficient that at least one type is contained.

[0033] The graph in Figure 4 shows an example of the spectral reflectance of a decorative sheet containing cobalt blue alone as the blue pigment in the picture layer 5, and a decorative sheet containing ultramarine alone as the blue pigment in the picture layer 5. Although the spectral reflectance varies depending on the type of blue pigment, qualitatively, a decorative sheet containing at least one type of blue pigment in the picture layer 5 has a minimum spectral reflectance in the wavelength range of 500 nm or more and 650 nm or less when measured from the picture layer 5 side. This allows the decorative sheet 1 to achieve good hiding power.

[0034] The opacity of a decorative sheet is judged by the color difference between a white substrate and a black substrate. As shown in FIG. 5, the spectral reflectance of a white sheet differs at wavelengths longer than 500 nm. Therefore, by adding at least one type of blue pigment to the design layer 5 laminated on the white sheet 2 and providing a minimum spectral reflectance in the wavelength range of 500 nm to 650 nm, as shown in FIG. 4, the spectral reflectance at longer wavelengths is reduced, resulting in a decorative sheet 1 with excellent opacity. In other words, by including at least one type of blue pigment in the design layer 5, the decorative sheet 1 can achieve excellent opacity without increasing the amount of pigment added. Therefore, the decorative sheet 1 according to this embodiment avoids the need for an increased amount of pigment, and can avoid the need for an increased amount of inorganic pigment added. It offers excellent flexibility, such as bendability, and excellent opacity.

[0035] Furthermore, to further improve the hiding power of the decorative sheet 1, it is desirable to use titanium oxide in combination with a pigment other than blue in the design layer 5, i.e., to contain a blue pigment and titanium oxide in the design layer 5. The decorative sheet 1 according to this embodiment only needs to contain titanium oxide in at least one of the white sheet 2 and the design layer 5. In this embodiment, the appropriate blending ratio of titanium oxide to blue pigment in the decorative sheet 1 is as follows: When the total amount of titanium oxide contained in the decorative sheet 1, i.e., the total amount of titanium oxide contained in at least one of the white sheet 2 and the design layer 5, is taken as 100 parts by mass, the amount of blue pigment added to the design layer 5 may be between 0.3 and 3 parts by mass, and more preferably between 1 and 2 parts by mass. If the amount of blue pigment added is less than 1 part by mass, it is difficult to achieve the effect of improving hiding power. Furthermore, if the amount of blue pigment added is more than 2 parts by mass, the design layer 5 becomes too blue, and the white sheet 2 laminated with the design layer 5 may not be perceived as white. Note that if the design layer 5 does not contain titanium oxide, the total amount of titanium oxide contained in the white sheet 2 corresponds to the total amount of titanium oxide contained in the decorative sheet 1. Furthermore, if the white sheet 2 does not contain titanium oxide, the total amount of titanium oxide contained in the design layer 5 corresponds to the total amount of titanium oxide contained in the decorative sheet 1.

[0036] In this embodiment, the decorative sheet 1 formed by the white sheet 2 and the pattern layer 5 contains titanium oxide and at least one type of blue pigment in the appropriate blending ratio described above, thereby more reliably achieving a spectral reflectance with a minimum value in the wavelength range of 500 nm or more and 650 nm or less.

[0037] Furthermore, when the decorative sheet 1 formed by the white sheet 2 and the picture layer 5 is measured for reflected chromaticity using a D65 light source from the picture layer 5 side, it is found that the L * is in the range of +90 to +100, and a * is between -1.5 and +1.5, and b * is preferably in the range of -1.5 or more and 2.0 or less. This allows the decorative sheet 1 according to this embodiment to obtain better hiding power. * , a * , b * In this embodiment, by containing titanium oxide and at least one type of blue pigment in the above-mentioned appropriate blending ratio, the reflected chromaticity values ​​(L * , a * , b * ) can be set within the above-mentioned appropriate range.

[0038] The Lab color system is a set of three values ​​(L * a * b * ) is a color system expressed in coordinates using L * indicates brightness, and the larger the value, from 0 to 100, the brighter it becomes. * , b * and a * , b * If both are 0, the color will be achromatic. * The more positive the value, the stronger the redness, and the more negative the value, the stronger the greenness. * The more positive the value, the stronger the yellowness, and the more negative the value, the stronger the blueness. In this embodiment, the reflected chromaticity of the decorative sheet 1 was measured using a spectrophotometer (530JP / LP) manufactured by X-rite, and was measured on a white background of an obscuration test paper (byko-chart high brightness 2A) manufactured by BYK-GARDNER, using the D65 light source, which is the standard light source defined by the International Commission on Illumination (CIE).

[0039] The materials contained in the design layer 5 other than the blue pigment and titanium oxide are not particularly limited. For example, printing inks or coating agents prepared by dissolving or dispersing a matrix and a colorant such as a dye or pigment in a solvent can be used. Examples of the matrix include various synthetic resins, such as oil-based nitrocellulose resin, two-component urethane resin, acrylic resin, styrene resin, polyester resin, urethane resin, polyvinyl resin, alkyd resin, epoxy resin, melamine resin, fluorine-containing resin, silicone resin, and rubber resin, as well as mixtures or copolymers thereof. Examples of the colorant include inorganic pigments such as carbon black, titanium white, zinc white, red iron oxide, yellow lead, and cadmium red; organic pigments such as azo pigments, lake pigments, anthraquinone pigments, phthalocyanine pigments, isoindolinone pigments, and dioxazine pigments; and mixtures thereof. As the solvent, for example, toluene, xylene, ethyl acetate, butyl acetate, methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, water, or a mixture thereof can be used.

[0040] In addition, functional additives such as extender pigments, plasticizers, dispersants, surfactants, tackifiers, adhesive aids, drying agents, curing agents, curing accelerators, and curing retarders may be added to the design layer 5 to impart various functions.

[0041] Furthermore, depending on the level of the desired design, a base solid ink layer may be provided as the pattern layer 5. The base solid ink layer is provided, for example, so as to cover the entire surface of the white sheet 2. The base solid ink layer may also be multi-layered, consisting of two or more layers, as needed for hiding properties, etc. Furthermore, the pattern layer 5 may be formed by laminating the same number of plates as necessary to express the desired design. In this way, the pattern layer 5 can be formed in various combinations depending on the desired design, i.e., the design to be expressed, but is not particularly limited.

[0042] Here, the design layer 5 can be formed by various printing methods, such as gravure printing, offset printing, screen printing, electrostatic printing, and inkjet printing. Furthermore, since the base solid ink layer covers the entire surface of the white sheet 2, it can also be formed by various coating methods, such as roll coating, knife coating, microgravure coating, and die coating. While these printing and coating methods may be selected separately depending on the layer to be formed, it is more efficient to select the same method and process all at once.

[0043] The thickness of the design layer 5 is preferably within the range of 3 μm to 20 μm. When the thickness of the design layer 5 is within this range, the printing can be made clear, the printing workability when producing the decorative sheet 1 is improved, and production costs can be reduced.

[0044] The thickness of the decorative sheet 1 may be in the range of 40 μm to 200 μm. Here, the design layer 5 and top coat layer 7 of the decorative sheet 1 are very thin. Therefore, the thicknesses of the design layer 5 and top coat layer 7 may be ignored, and the total thickness of the entire decorative sheet 1 may be designed to be 40 μm to 200 μm, considering only the thickness of the white sheet 2. In this embodiment, the thickness of the white sheet 2 may be in the range of 40 μm to 200 μm, and more preferably in the range of 50 μm to 150 μm. A thickness of less than 40 μm is undesirable because it significantly reduces the ability to cover irregularities (unevenness resistance) of the substrate (e.g., substrate B) to which the decorative sheet 1 is attached. On the other hand, a thickness of the decorative sheet 1 exceeding 200 μm may reduce bending workability, resulting in problems such as whitening and cracking.

[0045] <Transparent resin layer> The resin material used as the main component of the transparent resin layer 6 is preferably composed of an olefin-based resin, and in addition to polypropylene, polyethylene, polybutene, etc., α-olefins (for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-pent ... Examples of suitable olefins include homopolymers or copolymers of two or more of α-olefins (e.g., ethylene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.), as well as copolymers of ethylene or α-olefins with other monomers, such as ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, etc. Furthermore, when it is desired to improve the surface strength of the decorative sheet 1, it is preferable to use highly crystalline polypropylene.

[0046] When a transparent resin layer 6 is provided, the thickness of the transparent resin layer 6 is preferably within a range of 50 μm to 100 μm. If the thickness of the transparent resin layer 6 is less than 50 μm, the effect of improving the scratch resistance of the surface of the transparent resin layer 6 is low, and there is little point in providing the transparent resin layer 6. Furthermore, if the thickness of the transparent resin layer 6 exceeds 100 μm, the decorative sheet 1 may have too high rigidity, which may cause defects such as whitening and cracking during bending.

[0047] However, when the top coat layer 7 is provided on the transparent resin layer 6, the thickness of the transparent resin layer 6 may be less than 50 μm.

[0048] The resin composition constituting the transparent resin layer 6 may contain various functional additives, such as a heat stabilizer, a light stabilizer, an antiblocking agent, a catalyst scavenger, a colorant, a light scattering agent, and a gloss adjuster, as needed. These various functional additives can be appropriately selected from well-known additives.

[0049] The adhesive used to bond the design layer 5 and the transparent resin layer 6 can be any material, including lamination methods such as thermal lamination, extrusion lamination, and dry lamination. The adhesive can be selected from acrylic, polyester, and polyurethane materials. Due to their cohesive strength, two-component curing urethane materials that utilize the reaction between isocyanate and polyol are typically preferred. There are no particular restrictions on the lamination method for the design layer 5 and the transparent resin layer 6, but methods that apply heat and pressure, extrusion lamination, and dry lamination are common. To apply an embossed pattern 6a, a sheet may be laminated using various methods and then embossed using heat and pressure, or a cooling roll may be provided with a textured pattern and embossed simultaneously with extrusion lamination. Alternatively, a method may be used in which the pattern layer 5, which has been embossed simultaneously with extrusion, and the transparent resin layer 6 are bonded together by heat or dry lamination.

[0050] Furthermore, when further lamination strength is required in the extrusion lamination method, an adhesive resin layer 6b may be provided between the transparent resin layer 6 and the adhesive. When the adhesive resin layer 6b is provided, the transparent resin layer 6 and the adhesive resin layer 6b are laminated by co-extrusion. The adhesive resin layer 6b may be formed of, for example, an acid-modified resin such as polypropylene, polyethylene, or acrylic resin. The thickness of the adhesive resin layer 6b is preferably 2 μm or more to improve adhesive strength.

[0051] <Top coat layer> If further improvement in scratch resistance or adjustment of gloss is required, a top coat layer 7 can be provided on the surface of the transparent resin layer 6.

[0052] The resin material that is the main component of the top coat layer 7 can be appropriately selected from polyurethane-based, acrylic silicone-based, fluorine-based, epoxy-based, vinyl-based, polyester-based, melamine-based, aminoalkyd-based, urea-based, and other resin materials. The form of the resin material is not particularly limited, and may be aqueous, emulsion-based, solvent-based, or the like. The curing method can also be appropriately selected from one-component types, two-component types, ultraviolet curing, and the like.

[0053] As the resin material used as the main component of the top coat layer 7, a urethane-based resin using isocyanate is preferred from the viewpoints of workability, cost, the cohesive strength of the resin itself, etc. The isocyanate can be appropriately selected from curing agents such as adducts, biurets, and isocyanurates, which are derivatives of tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (HXDI), trimethylhexamethylene diisocyanate (TMDI), etc., but in consideration of weather resistance, curing agents based on hexamethylene diisocyanate (HMDI) or isophorone diisocyanate (IPDI), which have a linear molecular structure, are preferred. In addition, when improving the surface hardness, it is preferable to use a resin that is cured by active energy rays such as ultraviolet rays or electron beams. These resins can be used in combination with each other, and for example, by using a hybrid type of thermosetting and photocuring resins, it is possible to improve the surface hardness, suppress shrinkage on curing, and improve adhesion.

[0054] A gloss adjuster can be added to the top coat layer 7 to adjust the gloss. Commercially available gloss adjusters can be used. Examples of gloss adjusters include fine particles made of inorganic materials such as silica, glass, alumina, calcium carbonate, and barium sulfate. Alternatively, fine particles made of organic materials such as acrylic can also be used. However, when high transparency is required, it is desirable to use fine particles of highly transparent silica, glass, and acrylic. In particular, among fine particles such as silica and glass, gloss adjusters with low bulk density, which are formed by secondary aggregation of fine primary particles rather than solid spherical particles, have a high matting effect relative to the amount added. Therefore, by using such gloss adjusters, the amount of gloss adjuster added can be reduced.

[0055] Furthermore, functional additives such as antibacterial agents and antifungal agents may be added to impart various functions to the top coat layer 7. Furthermore, ultraviolet absorbers and light stabilizers may be added as needed. Examples of ultraviolet absorbers that can be used include benzotriazoles, benzoates, benzophenones, triazines, and cyanoacrylates. Furthermore, hindered amines can be used as light stabilizers.

[0056] The thickness of the top coat layer 7 is preferably in the range of 3 μm to 15 μm. If the thickness of the top coat layer 7 is less than 3 μm, the effect of improving scratch resistance is low, which may diminish the significance of providing the top coat layer 7. If the thickness of the top coat layer 7 exceeds 15 μm, cracks or breakage may occur during bending, which may cause problems with the design or deteriorate the weather resistance.

[0057] <Primer layer> The primer layer 8 can basically be made of the same material as the design layer 5. Considering that the primer layer 8 is applied to the back surface of the decorative sheet 1 and wound up in web form, the primer layer 8 may contain inorganic fillers such as silica, alumina, magnesia, titanium oxide, and barium sulfate. This prevents blocking of the primer layer 8 during winding and improves adhesion with the adhesive. The thickness of the primer layer 8 is preferably within the range of 0.1 μm to 3.0 μm, as its purpose is to ensure adhesion with the substrate B. The primer layer 8 is necessary when the white sheet 2 has an inactive surface, such as an olefin-based material, but is not particularly necessary when the surface is active.

[0058] "Manufacturing method" An example of a method for producing the decorative sheet 1 will now be described. It is desirable to mix polypropylene resin within a predetermined range into the colored layer 3 of the white sheet 2 to facilitate dispersion of the inorganic pigment. Furthermore, the polypropylene resin to be mixed is preferably a random polypropylene resin with an ethylene content or a known amorphous polypropylene resin. Furthermore, it is preferable to use a homopolypropylene resin with high crystallinity as the polypropylene resin used in the skin layer 4 of the white sheet 2. Polypropylene resins may be used alone or in combination. Furthermore, polyethylene resin may be mixed into the colored layer 3 within a predetermined range.

[0059] The resin material for the white sheet 2 described above is heated and melted, and formed into a sheet having a thickness in the range of 40 μm to 200 μm (preferably 50 μm to 150 μm) by extrusion molding or the like to form the white sheet 2.

[0060] Furthermore, a pattern layer 5 is formed on the upper surface of the white sheet 2 by printing. A blue pigment is added to the pattern layer 5 within the above-mentioned appropriate range. As a result, the decorative sheet 1 has a minimum value of spectral reflectance measured from the pattern layer 5 side in the wavelength range of 500 nm or more and 650 nm or less. In addition, at least one of a transparent resin layer 6 and a top coat layer 7 is formed on the pattern layer 5 as needed.

[0061] <Other effects> (1) The decorative sheet 1 of this embodiment is formed by laminating a white sheet 2 and a pattern layer 5 in this order, and the pattern layer 5 contains at least one type of blue pigment, and the spectral reflectance measured from the pattern layer 5 side has a minimum value in the wavelength range of 500 nm or more and 650 nm or less. With this configuration, it is not necessary to increase the amount of inorganic pigment added compared to the prior art, and therefore it is possible to provide a decorative sheet 1 that is excellent in flexibility and hiding power. (2) When the decorative sheet 1 according to this embodiment is measured for reflected chromaticity from the pattern layer 5 side using a D65 light source, the L * is in the range of +90 to +100, and a * is between -1.5 and +1.5, and b * is within the range of -1.5 or more and +2.0 or less. With this configuration, it is possible to provide a decorative sheet 1 with even better hiding properties.

[0062] (3) The decorative sheet 1 of this embodiment contains at least one of ultramarine, Prussian blue (milory blue), cobalt blue, cerulean blue, and gosu as a blue pigment in the design layer 5. With this configuration, it is possible to reliably provide a decorative sheet 1 with even better hiding power.

[0063] (4) The decorative sheet 1 of this embodiment may contain titanium oxide in at least one of the white sheet 2 and the design layer 5. With this configuration, it is possible to reliably provide a decorative sheet 1 with even better hiding power. (5) In the decorative sheet 1 of this embodiment, the amount of blue pigment added may be in the range of 0.3 parts by mass or more and 3 parts by mass or less, assuming that the total amount of titanium oxide contained in at least one of the white sheet 2 and the design layer 5 is 100 parts by mass. With this configuration, it is possible to reliably provide a decorative sheet 1 with even better hiding power.

[0064] (6) The decorative sheet 1 of this embodiment may contain titanium oxide in the design layer 5. With this configuration, it is possible to reliably provide a decorative sheet 1 with even better hiding power.

[0065] (7) In the decorative sheet 1 of this embodiment, the white sheet 2 may be primarily composed of polypropylene and titanium oxide. With this configuration, it is not necessary to increase the amount of inorganic pigment added compared to conventional techniques, and therefore a decorative sheet 1 with excellent flexibility and hiding power can be provided. (8) In the decorative sheet 1 of this embodiment, the white sheet 2 may be primarily composed of polyethylene and titanium oxide. With this configuration, it is not necessary to increase the amount of inorganic pigment added compared to conventional techniques, and therefore a decorative sheet 1 with excellent flexibility and hiding power can be provided.

[0066] (9) The thickness of the decorative sheet 1 of this embodiment may be within the range of 40 μm or more and 200 μm or less. With this configuration, the decorative sheet 1 can be endowed with both unevenness resistance and bending workability. (10) In this embodiment, by adding a blue pigment to the pattern layer 5, a decorative sheet 1 is produced that has a minimum value of spectral reflectance measured from the pattern layer 5 side in the wavelength region of 500 nm or more and 650 nm or less. This makes it possible to produce a decorative sheet 1 that is excellent in flexibility and hiding power without increasing the amount of inorganic pigment added compared to conventional techniques.

[0067] [Example] Specific examples of the decorative sheet 1 of this embodiment will be described below.

[0068] Example 1 The raw materials for the colored layer 3 were 60 parts by mass of polypropylene resin and 40 parts by mass of titanium oxide pigment as an inorganic pigment. The raw materials for the skin layer 4 were 100 parts by mass of polypropylene resin and 0.5 parts by mass of a hindered amine light stabilizer (BASF's "Chimassorb 944") and 0.5 parts by mass of a benzotriazole UV absorber (BASF's "Tinuvin 328") were added and mixed. The mixture for the colored layer 3 and the mixture for the skin layer 4 were co-extruded using a melt extruder in the order of skin layer 4, colored layer 3, and skin layer 4 to thicknesses of 10 μm:120 μm:10 μm, to form a white sheet 2 with a thickness of 140 μm.

[0069] A picture was printed on the surface of a 140 μm-thick white sheet 2 to form a picture layer 5. For the picture layer 5, a cobalt blue pigment was added as a blue pigment to a two-component urethane ink (V180; manufactured by Toyo Ink Co., Ltd.) in an amount of 0.4 parts by mass relative to the binder resin content of the ink. The amount of cobalt blue pigment added was 0.4 parts by mass relative to 40 parts by mass of the titanium oxide pigment added to the colored layer 3. Furthermore, 0.5 parts by mass of a hindered amine light stabilizer (Chimasorb 944; manufactured by BASF) was added to the ink to form the picture layer 5. A primer layer 8 was also formed on the back surface of the white sheet 2. The primer layer 8 was formed by printing the same two-component urethane ink as used for the picture layer 5. In this way, the decorative sheet 1 of Example 1 was obtained.

[0070] Example 2 A decorative sheet 1 of Example 2 was formed in the same manner as in Example 1, except that the blue pigment added to the design layer 5 was 0.8 parts by mass of cobalt blue pigment.

[0071] Example 3 A decorative sheet 1 of Example 3 was formed in the same manner as in Example 1, except that the blue pigment added to the above-mentioned design layer 5 was 0.4 parts by mass of ultramarine blue pigment.

[0072] Example 4 A decorative sheet 1 of Example 4 was formed in the same manner as in Example 1, except that the blue pigment added to the design layer 5 was 0.2 parts by mass of cobalt blue pigment.

[0073] Example 5 A decorative sheet 1 of Example 5 was formed in the same manner as in Example 1, except that the blue pigment added to the design layer 5 was 1.0 part by mass of cobalt blue pigment.

[0074] Example 6 The decorative sheet 1 of Example 6 was formed in the same manner as Example 1, except that 0.2 parts by mass of cobalt blue pigment was added to the above-mentioned pattern layer 5, and 20 parts by mass of titanium oxide was added to the pattern layer 5.

[0075] Example 7 Using the same mixture of colored layer 3 and skin layer 4 as in Example 1, the layers were co-extruded using a melt extruder in the order of skin layer 4, colored layer 3, and skin layer 4 to a thickness of 3 μm:44 μm:3 μm, to form a white sheet 2 having a thickness of 50 μm.

[0076] A design layer 5 was formed on the surface of the 50 μm thick white sheet 2 in the same manner as in Example 1, to obtain a decorative sheet 1 of Example 7.

[0077] Example 8 Using the same mixture of colored layer 3 and skin layer 4 as in Example 1, a melt extruder was used to co-extrude the skin layer 4, colored layer 3, and skin layer 4 in that order to form a thickness of 3 μm:94 μm:3 μm, thereby forming a white sheet 2 having a thickness of 100 μm.

[0078] A design layer 5 was formed on the surface of the 100 μm thick white sheet 2 in the same manner as in Example 1, to obtain a decorative sheet 1 of Example 8.

[0079] Example 9 Using the same mixture of colored layer 3 and skin layer 4 as in Example 1, the layers were co-extruded using a melt extruder in the order of skin layer 4, colored layer 3, and skin layer 4 to a thickness of 3 μm:34 μm:3 μm, to form a white sheet 2 having a thickness of 40 μm.

[0080] A design layer 5 was formed on the surface of the above-mentioned 40 μm thick white sheet 2 in the same manner as in Example 1, to obtain a decorative sheet 1 of Example 9.

[0081] Example 10 Using the same mixture of colored layer 3 and skin layer 4 as in Example 1, a melt extruder was used to co-extrude the skin layer 4, colored layer 3, and skin layer 4 in that order to form a thickness of 10 μm:160 μm:10 μm, thereby forming a white sheet 2 having a thickness of 180 μm.

[0082] A design layer 5 was formed on the surface of the 180 μm thick white sheet 2 in the same manner as in Example 1, to obtain a decorative sheet 1 of Example 10.

[0083] Example 11 The raw materials for the colored layer 3 were 60 parts by mass of polypropylene resin, to which were added and mixed 40 parts by mass of titanium oxide pigment as an inorganic pigment, 0.3 parts by mass of a hindered amine-based light stabilizer (BASF's "Chimasorb 944"), and 0.3 parts by mass of a benzotriazole-based UV absorber (BASF's "Tinuvin 328") The skin layer 4 was not formed, and the colored layer 3 was extruded using a melt extruder to a thickness of 120 μm to form a white sheet 2.

[0084] A design layer 5 was formed on the surface of the 120 μm thick white sheet 2 in the same manner as in Example 1, to obtain a decorative sheet 1 of Example 11.

[0085] Example 12 The raw materials for the colored layer 3 were 60 parts by weight of polyethylene resin and 40 parts by weight of titanium oxide pigment as an inorganic pigment. The raw materials for the skin layer 4 were 100 parts by weight of polypropylene resin and 0.5 parts by weight of a hindered amine light stabilizer (BASF's "Chimassorb 944") and 0.5 parts by weight of a benzotriazole UV absorber (BASF's "Tinuvin 328") were added and mixed. The mixture for the colored layer 3 and the mixture for the skin layer 4 were co-extruded using a melt extruder in the order of skin layer 4, colored layer 3, and skin layer 4 to a thickness of 10 μm:120 μm:10 μm, to form a white sheet 2 with a thickness of 140 μm.

[0086] A design layer 5 was formed on the surface of the 140 μm thick white sheet 2 in the same manner as in Example 1, to obtain a decorative sheet 1 of Example 12.

[0087] Example 13 The raw materials for the colored layer 3 were 70 parts by mass of polypropylene resin and 30 parts by mass of titanium oxide pigment, and the materials were co-extruded using a melt extruder in the same manner as in Example 1 to produce a white sheet 2 having a thickness of 140 μm.

[0088] A picture was printed on the surface of the 140 μm-thick white sheet 2 to form a picture layer 5. The picture layer 5 was formed by adding cobalt blue pigment as a blue pigment to a two-component urethane ink (V180; manufactured by Toyo Ink Co., Ltd.) relative to the binder resin content of the ink. The amount of cobalt blue pigment added was 0.3 parts by mass relative to 30 parts by mass of the titanium oxide pigment added to the colored layer 3. Furthermore, the ink was formed by adding 0.5 parts by mass of a hindered amine light stabilizer (Chimasorb 944; manufactured by BASF). A primer layer 8 was also formed on the back surface of the white sheet 2. The primer layer 8 was formed by printing the same two-component urethane ink as the picture layer 5. In this way, the decorative sheet 1 of Example 13 was obtained.

[0089] Example 14 The raw materials for the colored layer 3 were 80 parts by mass of polypropylene resin and 20 parts by mass of titanium oxide pigment, and the materials were co-extruded using a melt extruder in the same manner as in Example 1 to produce a white sheet 2 having a thickness of 140 μm.

[0090] A picture was printed on the surface of the 140 μm-thick white sheet 2 to form a picture layer 5. The picture layer 5 was formed by adding cobalt blue pigment as a blue pigment to a two-component urethane ink (V180; manufactured by Toyo Ink Co., Ltd.) relative to the binder resin content of the ink. The amount of cobalt blue pigment added was 0.2 parts by mass relative to 20 parts by mass of the titanium oxide pigment added to the colored layer 3. Furthermore, the ink was formed by adding 0.5 parts by mass of a hindered amine light stabilizer (Chimasorb 944; manufactured by BASF). A primer layer 8 was also formed on the back surface of the white sheet 2. The primer layer 8 was formed by printing the same two-component urethane ink as the picture layer 5. In this way, the decorative sheet 1 of Example 14 was obtained.

[0091] Example 15 The raw materials for the colored layer 3 were 80 parts by mass of polypropylene resin and 20 parts by mass of titanium oxide pigment, and the materials were co-extruded using a melt extruder in the same manner as in Example 1 to produce a white sheet 2 having a thickness of 140 μm.

[0092] In addition, the decorative sheet 1 of Example 15 was formed in the same manner as Example 1, except that 20 parts by mass of titanium oxide was added as the pigment to the above-mentioned pattern layer 5, and the amount of cobalt blue pigment added was 0.2 parts by mass relative to the total of 40 parts by mass of titanium oxide contained in the white sheet 2 and pattern layer 5.

[0093] Example 16 A pattern was printed on the surface of a 140 μm thick white sheet 2 produced in the same manner as in Example 1 to form a pattern layer 5 in the same manner as in Example 1, and a two-component curing urethane top coat ("W184" manufactured by DIC Graphics Corporation) was applied on the pattern layer 5 in an amount of 3 g / m 2to form a top coat layer 7. In this way, a decorative sheet 1 of Example 16 was obtained.

[0094] Example 17 A pattern layer 5 similar to that of Example 2 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 1, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 17.

[0095] Example 18 A pattern layer 5 similar to that of Example 3 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 1, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 18.

[0096] Example 19 A pattern layer 5 similar to that of Example 4 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 1, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 19.

[0097] Example 20 A pattern layer 5 similar to that of Example 5 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 1, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 20.

[0098] Example 21 A pattern layer 5 similar to that of Example 6 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 1, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 21.

[0099] Example 22 A pattern layer 5 similar to that of Example 7 was formed on the surface of a 50 μm thick white sheet 2 prepared in the same manner as in Example 7, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 22.

[0100] Example 23 A pattern layer 5 similar to that of Example 8 was formed on the surface of a 100 μm thick white sheet 2 prepared in the same manner as in Example 8, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 23.

[0101] Example 24 A pattern layer 5 similar to that of Example 9 was formed on the surface of a 40 μm thick white sheet 2 prepared in the same manner as in Example 9, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 24.

[0102] Example 25 A pattern layer 5 similar to that of Example 10 was formed on the surface of a 180 μm thick white sheet 2 prepared in the same manner as in Example 10, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 25.

[0103] Example 26 A pattern layer 5 similar to that of Example 11 was formed on the surface of a 120 μm thick white sheet 2 prepared in the same manner as in Example 11, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 26.

[0104] Example 27 A pattern layer 5 similar to that of Example 12 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 12, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 27.

[0105] Example 28 A pattern layer 5 similar to that of Example 13 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 13, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 28.

[0106] Example 29 A pattern layer 5 similar to that of Example 14 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 14, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 29.

[0107] Example 30 A pattern layer 5 similar to that of Example 15 was formed on the surface of a 140 μm thick white sheet 2 prepared in the same manner as in Example 15, and a top coat layer 7 was then formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining the decorative sheet 1 of Example 30.

[0108] (Comparative Example 1) A decorative sheet 1 of Comparative Example 1 was formed in the same manner as in Example 7, except that no blue pigment was added to the above-mentioned design layer 5.

[0109] (Comparative Example 2) A 50 μm thick white sheet 2 was prepared in the same manner as in Comparative Example 1, and a pattern layer 5 similar to that of Comparative Example 1 was formed on the surface of the white sheet 2.Furthermore, a top coat layer 7 was formed on the pattern layer 5 in the same manner as in Example 16, thereby obtaining a decorative sheet 1 of Comparative Example 2.

[0110] (Comparative Example 3) A decorative sheet 1 of Comparative Example 3 was formed in the same manner as in Example 1, except that the blue pigment added to the design layer 5 was 1.2 parts by mass of cobalt blue pigment.

[0111] [evaluation] The decorative sheets 1 of Examples 1-30 and Comparative Examples 1-3 were evaluated for spectral reflectance, hue, hiding power, and bending processability.

[0112] <Spectral reflectance> The spectral reflectance was measured using a fluorescence spectrodensitometer (FD-7) manufactured by Konica Minolta, Inc., and the spectral reflectance was obtained in the wavelength region of 400 nm to 700 nm. When the hiding power of the white sheet 2 is low, it is affected by the color of the base. Therefore, for all decorative sheets 1 of Examples 1-30 and Comparative Examples 1-3, a hiding test paper (byko-cha) manufactured by BYK-GARDNER was used. Measurements were taken on a white background (high brightness 2A).

[0113] <Hue> Hue was evaluated using an X-rite spectrophotometer (530JP / LP) and chromaticity (reflected chromaticity) measured on a white background using BYK-GARDNER's obscuration test paper (byko-chart high brightness 2A) under the D65 light source, the standard light source defined by the International Commission on Illumination (CIE).

[0114] <Concealment> The hiding power was evaluated using an X-rite spectrophotometer (530JP / LP) and judged by the color difference measured on a white and black background using BYK-GARDNER hiding test paper (byko-chart high brightness 2A). The smaller the color difference, the better the hiding power. A color difference of 0.5 or less was rated as "◎", more than 0.5 and less than 0.7 was rated as "○", more than 0.7 and less than 1.0 was rated as "△", and more than 1.0 was rated as "×". Note that a rating of "△" or higher indicates no practical problems.

[0115] <Bending workability> The bending workability was evaluated by the following bending workability test. In the bending processability test, first, a medium density fiberboard (MDF) was used as substrate B to which decorative sheet 1 was attached. Each of the decorative sheets 1 of Examples 1-30 and Comparative Examples 1-3 obtained by the method described above was attached to one side of substrate B using a urethane adhesive. A V-shaped groove was made on the other side of substrate B up to the boundary where substrate B and decorative sheet 1 were attached, so as to prevent scratches on the decorative sheet 1 attached to the opposite side. Next, substrate B was bent 90 degrees along the V-shaped groove so that the surface to which decorative sheet 1 was attached formed a mountain fold, and the bent portion of the surface of decorative sheet 1 was observed using a microscope (Keyence VHX-1000) to check for whitening, cracks, etc., and the state of bending processability was evaluated. As a result of observation under an optical microscope, when no whitening or cracks were observed, the rating was "◎", when slight whitening was observed in some areas, the rating was "○", when whitening was observed in some areas, the rating was "△", and when whitening was observed over the entire surface or when cracks were observed in some areas, the rating was "×". Note that an evaluation of "△" or higher is acceptable for practical use.

[0116] The evaluation results are shown in Table 1. [Table 1]

[0117] (Spectral reflectance evaluation results) As shown in Table 1, the decorative sheet 1 of Example 1-30 contained a blue pigment in the design layer 5, resulting in a minimum value of spectral reflectance ("Yes"). Here, the spectral reflectances of the decorative sheets 1 of Examples 1-4 and Comparative Example 1 are shown in Figure 6 as representative examples. Because the decorative sheet 1 of Example 1-4 contains a blue pigment in the design layer 5, it has a minimum spectral reflectance in the wavelength range of 500 nm to 650 nm. Although not shown, Examples 5-30 also have similar spectral reflectance characteristics to Examples 1-4, with a minimum spectral reflectance in the same wavelength range. As a result, the decorative sheet 1 of Examples 1-30 received a concealment evaluation result of "Fair" or better, achieving a level of concealment that is at least acceptable for practical use. On the other hand, the decorative sheet 1 of Comparative Example 1 does not contain a blue pigment in the design layer 5, and therefore exhibits a monotonically decreasing spectral reflectance. Furthermore, the decorative sheet 1 of Comparative Example 2 also has the same spectral reflectance characteristics as Comparative Example 1, and similarly exhibits a monotonically decreasing spectral reflectance (not shown). Therefore, the decorative sheets 1 of Comparative Examples 1 and 2 were both rated "Poor" for concealment, indicating that their concealment was not practically acceptable.

[0118] (Evaluation results of opacity and bending workability) As shown in Table 1, in each of the decorative sheets 1 of Examples 1-3 and 16-18, the white sheet 2 contained 40 parts by mass of titanium oxide and the picture layer 5 contained 0.4 parts by mass or more of blue pigment, so that the hiding power was very good and the hiding power evaluation result was "◎". The bending processability was also good and the bending processability evaluation result was "◯". Furthermore, each of the decorative sheets 1 of Examples 16-18 has a structure in which a top coat layer 7 is laminated on the picture layer 5 of each of the decorative sheets 1 of Examples 1-3. As shown in Table 1, it can be seen that each of the decorative sheets 1 of Examples 16-18, which is provided with a top coat layer 7, is able to achieve both excellent hiding power and excellent bending processability while imparting a sophisticated design.

[0119] Furthermore, as shown in Table 1, the decorative sheets 1 of Examples 4 and 19 were evaluated for hiding power as "good." Each of the decorative sheets 1 of Examples 4 and 19 contained 40 parts by mass of titanium oxide in the white sheet 2 and 0.2 parts by mass of blue pigment in the picture layer 5, with the amount of blue pigment added to the picture layer 5 being small. As a result, hiding power was slightly reduced compared to the decorative sheets 1 of Examples 1-3, but was still at a good level. Furthermore, each of the decorative sheets 1 of Examples 4 and 19 had good bending processability (evaluation result of "good").

[0120] In each of the decorative sheets 1 of Examples 5 and 20, the amount of titanium oxide added to the white sheet 2 was 40 parts by mass, and the amount of blue pigment added was 1.0 part by mass, which was a large blend to produce the pattern layer 5. As a result, as will be described later, the hue was leaning towards blue (b* was on the negative side), but the hiding power was very good. The result was good (evaluation result was "A").

[0121] In each of the decorative sheets 1 of Examples 6 and 21, the white sheet 2 contained 40 parts by mass of titanium oxide, and the picture layer 5 contained 0.2 parts by mass of blue pigment and 20 parts by mass of titanium oxide. As a result, the hiding power was very good (evaluated as "◎"). Furthermore, because of the high pigment content, the bending processability was reduced compared to the decorative sheets 1 of Examples 1-3, but this was at a level that was not problematic in practical use (evaluated as "△").

[0122] The decorative sheets 1 of Examples 8 and 23 were each produced so that the thickness of the colored layer 3 was 94 μm, which was thinner than, for example, the colored layer 3 of the decorative sheets 1 of Examples 1-3. As a result, although the hiding power was reduced, it was still at a good level (evaluation result: "O"). Furthermore, the decorative sheets 1 of Examples 8 and 23 each had good bending processability (evaluation result: "O").

[0123] The decorative sheets 1 of Examples 7 and 22 were each produced so that the thickness of the colored layer 3 was 44 μm, thinner than the decorative sheets 1 of Examples 8 and 23. As a result, the hiding power was reduced, but was still at a good level (evaluation result: "O"). Furthermore, the decorative sheets 1 of Examples 7 and 22 each had good bending processability (evaluation result: "O").

[0124] The decorative sheets 1 of Examples 9 and 24 were each produced so that the thickness of the colored layer was 34 μm, even thinner than the decorative sheets of Examples 7 and 22. As a result, the hiding power was significantly reduced, but it was at a level that was not problematic in practical use (evaluation result: "△"). Furthermore, the decorative sheets 1 of Examples 9 and 24 each had good bending processability (evaluation result: "◯").

[0125] The decorative sheets 1 of Examples 10 and 25 were each produced with a colored layer thickness of 160 μm, which was thicker than, for example, the colored layer 3 of the decorative sheets 1 of Examples 1-3. As a result, the hiding power was very good (evaluated as "◎"). On the other hand, the bending processability was reduced, but was at a level that was not problematic in practical use (evaluated as "△").

[0126] The decorative sheets 1 of Examples 11 and 26 were good in both hiding power and bending processability (evaluation result: "Good"). Furthermore, in the decorative sheets 1 of Examples 11 and 26, the skin layer 4 was not formed on the white sheet 2, and there was concern about bleeding out of the pigment component of the colored layer 3, but in this evaluation, no film formation defects were observed.

[0127] The decorative sheets 1 of Examples 12 and 27 used polyethylene resin instead of polypropylene resin, but the hiding power was very good (evaluation result: "◎") and the bending processability was also good (evaluation result: "◯"), resulting in a problem-free finish.

[0128] In the decorative sheets of Examples 13 and 28, the amount of titanium oxide added to the white sheet 2 was 30 parts by mass, which was less than that of Example 1, so the hiding power was slightly reduced, but it was still at a good level (evaluation result: "O") and the bending processability was also good (evaluation result: "O").

[0129] In the decorative sheets 1 of Examples 14 and 29, the amount of titanium oxide added to the white sheet 2 was 20 parts by mass, which was significantly less than that of Example 1, so the hiding power was further reduced, but it was still at a level that was not problematic in practical use (evaluation result: "△"). In addition, the bending processability was also good (evaluation result: "◯").

[0130] In the decorative sheets 1 of Examples 15 and 30, the amount of titanium oxide added to the white sheet 2 was 20 parts by mass, which is considerably less than that of Example 1, but the amount of titanium oxide added to the picture layer 5 was 20 parts by mass, making the total amount of titanium oxide added 40 parts by mass. As a result, the hiding power was good (evaluation result: "Good") and the bending processability was also at a good level (evaluation result: "Good").

[0131] The decorative sheets of Comparative Examples 1 and 2 do not contain a blue pigment in the picture layer 5. For this reason, as described above, the spectral reflectance does not have a minimum value in the wavelength region of 500 nm or more and 650 nm or less, and as a result, the hiding power is poor, resulting in decorative sheets that are not suitable for practical use (evaluation result: "X").

[0132] (Hue evaluation results) As described above, in each of the decorative sheets 1 of Examples 5 and 20, the design layer 5 was prepared with a large blend of 1.0 part by mass of blue pigment added to 40 parts by mass of titanium oxide added in total. As a result, although the hue leaned toward blue (b* was on the negative side), this was at a level that was not problematic in practical use. In the decorative sheets 1 of the examples other than Examples 5 and 20, the hue did not lean towards the blue side. On the other hand, the decorative sheet 1 of Comparative Example 3 had a pattern layer 5 prepared with a very high amount of blue pigment added, at 1.2 parts by mass. As a result, the hue of the decorative sheet 1 of Comparative Example 3 was significantly leaning towards blue (b* value was -1.75), to the point where the white sheet 2 could not be recognized as white. As a result, the decorative sheet 1 of Comparative Example 3 was a decorative sheet of a level that was not suitable for practical use.

[0133] From the above, it was clear that the decorative sheet 1 of Example 1-30 was a decorative sheet that could avoid an increase in the amount of inorganic pigment added, had excellent flexibility in bending processability, and had excellent hiding power. The decorative sheet of the present invention is not limited to the above-described embodiments and examples, and various modifications are possible within the scope that does not impair the characteristics of the invention. [Industrial Applicability]

[0134] As explained above, the present invention is a technology particularly suitable for decorative sheets used as building materials for the exterior and interior of buildings, surfaces of building fixtures, surface materials for home appliances, and the like. [Explanation of symbols]

[0135] 1 decorative sheet 2 white sheets 3 Colored layer 4 Skin Layer 5. Picture layer 6 Transparent resin layer 6a Embossed pattern 6b Adhesive resin layer 7 Topcoat layer 8 Primer layer B board

Claims

1. A decorative sheet in which at least a white sheet and a pattern layer are laminated in this order, the design layer contains only a blue pigment or only the blue pigment and titanium oxide as a pigment, The spectral reflectance measured from the pattern layer side has a minimum value in a wavelength region of 500 nm or more and 650 nm or less, When the reflected chromaticity is measured from the pattern layer side using a D65 light source, In the Lab color system, L* is in the range of +90 to +100, a* is in the range of -1.5 to +1.5, and b* is in the range of -1.5 to +2.

0. A decorative sheet characterized by:

2. At least one of the white sheet and the design layer contains titanium oxide.

2. The decorative sheet according to claim 1, wherein:

3. When the total amount of titanium oxide contained in at least one of the white sheet and the design layer is 100 parts by mass, the amount of the blue pigment added is in the range of 0.3 parts by mass to 3 parts by mass.

3. The decorative sheet according to claim 2, wherein:

4. The design layer contains titanium oxide.

4. The decorative sheet according to claim 1, wherein the decorative sheet is a sheet having a thickness of 100 μm or more.

5. The pattern layer is formed on the surface of the white sheet.

5. The decorative sheet according to claim 1, wherein:

6. The main components of the white sheet are polypropylene and titanium oxide.

6. The decorative sheet according to any one of claims 1 to 5, wherein:

7. The main components of the white sheet are polyethylene and titanium oxide.

6. The decorative sheet according to any one of claims 1 to 5, wherein:

8. The thickness of the decorative sheet is within the range of 40 μm or more and 200 μm or less.

8. The decorative sheet according to claim 1, wherein:

9. The design layer contains one of ultramarine and cobalt blue as the blue pigment.

5. The decorative sheet according to claim 1, wherein:

10. A method for producing a decorative sheet according to any one of claims 1 to 9, By adding only a blue pigment or only the blue pigment and titanium oxide to the pattern layer as the pigment, the decorative sheet can be produced, which has a minimum value of spectral reflectance measured from the pattern layer side in a wavelength region of 500 nm or more and 650 nm or less, and when the reflected chromaticity is measured from the pattern layer side using a D65 light source, L* is in the range of +90 or more and +100 or less, a* is in the range of -1.5 or more and +1.5 or less, and b* is in the range of -1.5 or more and +2.0 or less in the Lab color system. A method for producing a decorative sheet, characterized by:

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