decorative sheet

Abstract

To provide a decorative sheet excellent in scratch resistance while capable of preventing an elongation during print processing and of reducing occurrence of flexural whitening or cracking, and a method of manufacturing the decorative sheet.SOLUTION: A decorative sheet 1 of the present embodiment includes a substrate layer 2 composed of a pigmented polypropylene film formed by mixing an inorganic pigment in a polypropylene resin. The substrate layer 2 also contains a nano-sized nucleating agent. The substrate layer 2 has a value of peak intensity ratio x, calculated from an absorption spectrum obtained by Fourier-type infrared spectroscopy, of 0.7 or more and 0.9 or less. The thickness of the substrate layer 2 is 50 μm or more and 150 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to decorative sheets used for building exteriors and interiors, surfaces of building fixtures, surface materials for home appliances, and the like. [Background technology]

[0002] In recent years, as shown in Patent Document 1, many decorative sheets using olefin resins (e.g., polypropylene sheets) have been proposed as alternatives to polyvinyl chloride decorative sheets, which pose environmental concerns. These decorative sheets do not use polyvinyl chloride resin, thus suppressing the generation of toxic gases during incineration. However, polypropylene sheets generally have drawbacks, such as poor scratch resistance due to their low elastic modulus and their tendency to stretch easily when tension is applied during sheet creation, such as during printing.

[0003] By the way, decorative sheets are applied to the surface of substrates such as wood substrates, metal substrates, and non-combustible substrates to create decorative panels, and the decorative sheets provide the decorative panels with a design appropriate to the purpose. Therefore, the decorative sheets need to cover the surface of the substrate so that it is not visible as needed. In this case, it is necessary to use decorative sheets that are colored with pigments and have opacity. The simplest configuration of a decorative sheet is a base layer consisting only of a single colored sheet (single layer). In the case of a decorative sheet consisting only of such a base layer, the design that can be applied is usually limited to a single color without a pattern, but by adding a glossy material such as aluminum flakes or pearl pigments as pigments, a glossy effect can be added, so sufficient design expression is possible. Furthermore, if a more sophisticated design is desired, it is also effective to apply decorations such as printing to the surface of the base layer.

[0004] On the other hand, as mentioned above, colored polypropylene films have a low elastic modulus, so when used as a single-layer decorative sheet, it is necessary to ensure scratch resistance and prevent stretching when tension is applied during processing such as printing. Regarding stretching when tension is applied, conventional colored polypropylene films can be improved by increasing the layer thickness to about 50 μm or more. Furthermore, regarding scratch resistance, conventional colored polypropylene films can be improved by providing a transparent resin layer made of polypropylene resin or a topcoat layer using a urethane-based thermosetting resin made of polyol and isocyanate, as described in Patent Documents 2 and 3.

[0005] Furthermore, as described in Patent Documents 2 and 3, it is possible to improve scratch resistance and elongation during printing by optimally selecting the polypropylene resin used in the colored polypropylene film. However, while increasing crystallinity improves the elastic modulus, the breaking stress does not increase proportionally to the elastic modulus, making the film itself more prone to tearing, and thus more likely to cause defects such as tearing during printing. Moreover, during post-processing as a decorative sheet, especially during bending processes such as V-cuts, defects such as cracking and whitening at the bent areas are more likely to occur. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 3271022 [Patent Document 2] Patent No. 3861472 [Patent Document 3] Patent No. 3772634 [Overview of the project] [Problems that the invention aims to solve]

[0007] Conventionally, decorative sheets using colored polypropylene film alone, or decorative sheets with colored polypropylene film as a base layer, have been required to have both printability (resistance to stretching, etc.), scratch resistance, and flexibility. This invention has been made in view of the above-mentioned points, and aims to provide a decorative sheet using a colored polypropylene film alone, a decorative sheet with a colored polypropylene film as a base layer, or a method for manufacturing such decorative sheets, which can improve scratch resistance, suppress elongation during printing, and reduce the occurrence of bending whitening and cracking. [Means for solving the problem]

[0008] The inventors have found that by encapsulating a nucleating agent that improves the crystallinity of polypropylene in a vesicle having a single-layer outer film, for example, and adding it as a nucleating agent vesicle, and further conducting various studies and experiments on the manufacturing process to optimize the crystallinity, they can provide a decorative sheet and a method for manufacturing the same that improves the above-mentioned problems. To achieve the objective, a decorative sheet according to one aspect of the present invention has a base layer made of a colored polypropylene film obtained by mixing an inorganic pigment with a polypropylene resin, the base layer contains a nano-sized nucleating agent, the thickness of the base layer is 50 μm or more and 150 μm or less, and the value of the peak intensity ratio x calculated from the absorption spectrum obtained by Fourier infrared spectroscopy is 0.7 or more and 0.9 or less. In addition, in the decorative sheet according to one aspect of the present invention, the nucleating agent may be contained in the form of nucleating agent vesicles that are encapsulated in the outer film and formed into vesicles. Here, a nucleating agent vesicle is a capsule-shaped vesicle with a single-layer outer membrane in which the nucleating agent is encapsulated, and can be prepared, for example, by supercritical reverse-phase evaporation. Furthermore, the nucleating agent is a substance that acts as a starting point for crystallization in crystalline polypropylene resin. [Effects of the Invention]

[0009] According to one aspect of the present invention, a decorative sheet can be provided that has printability (resistance to stretching, etc.), scratch resistance, and bendability by, for example, vesicling a nucleating agent to improve the crystallinity of polypropylene and adding it as a nucleating agent vesicle, and by optimizing the peak intensity ratio value and film thickness obtained in Fourier infrared spectroscopy. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view showing a decorative sheet according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view showing another decorative sheet according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. Here, the drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of the thickness of each layer, etc., may differ from reality. Furthermore, the embodiments shown below illustrate configurations for realizing the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not limit the materials, shapes, and structures 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 described in the patent claims.

[0012] "composition" The decorative sheet 1 in the embodiment shown in Figure 1 is an example of a single-layer structure consisting only of a base layer 2 (raw material layer). The base layer 2 in this embodiment is made of a colored polypropylene film. The base layer 2, which is made of a colored polypropylene film, contains an inorganic pigment mixed with polypropylene resin for coloring, as well as a nano-sized nucleating agent. In this embodiment, the nucleating agent may be contained, for example, in the form of nucleating agent vesicles that are enclosed in an outer film and formed into vesicles.

[0013] The thickness of the base material layer 2 is 50 μm or more and 150 μm or less, and the peak intensity ratio x calculated from the absorption spectrum obtained by Fourier transform infrared spectroscopy is 0.7 or more and 0.9 or less. The polypropylene resin constituting the base material layer 2 preferably has 50% by mass or more and 100% by mass or less of a highly crystalline homopolypropylene resin with an isotactic pentad fraction (mmmm fraction) of 95% or more.

[0014] The addition amount of the nano-sized nucleating agent is preferably 0.01 part by mass or more and 0.5 part by mass or less with respect to 100 parts by mass of the polypropylene resin. When using a nucleating agent vesicle, the addition amount of the nucleating agent vesicle is preferably 0.01 part by mass or more and 0.5 part by mass or less in terms of the nucleating agent in the nucleating agent vesicle with respect to 100 parts by mass of the polypropylene resin. The nucleating agent vesicle is preferably a nucleating agent liposome having an outer membrane made of phospholipid.

[0015] If necessary, a pattern layer 3 may be formed (laminated) on one surface of the base material layer 2 to improve the design property. Also, in the decorative sheet 1, at least one of the transparent resin layer 4 and the top coat layer 5 may be laminated on one surface side of the base material layer 2. The decorative sheet 1 illustrated in FIG. 2 is an example in which the pattern layer 3, the transparent resin layer 4, and the top coat layer 5 are laminated in this order on one surface of the decorative sheet 1. One of the transparent resin layer 4 or the top coat layer 5 may be omitted. Also, the pattern layer 3 may be omitted.

[0016] Here, at least one of the transparent resin layer 4 and the top coat layer 5 may be provided with an embossed concavo-convex pattern (embossed pattern 4a) depending on the design requirements. Ink can be embedded in the embossed pattern 4a to further improve the design. Also, if there is a problem with the adhesion between the pattern layer 3 and the transparent resin layer 4, an adhesive resin layer 4b may be provided as appropriate. When providing the adhesive resin layer 4b, it is formed by a co-extrusion method of the transparent resin layer 4 and the adhesive resin layer 4b. The adhesive resin layer 4b is, for example, a resin such as polypropylene, polyethylene, or acrylic resin that has been acid-modified. The thickness of the adhesive resin layer 4b is desirably 2 μm or more for the purpose of improving the adhesive strength. Further, depending on requirements such as scratch resistance, it is also possible to laminate a plurality of layers of at least one of the transparent resin layer 4 and the top coat layer 5, and other known layers may be arranged as well.

[0017] In FIGS. 1 and 2, reference numeral B represents a substrate. The substrate B is a substrate to which the decorative sheet 1 is bonded. The substrate B is not particularly limited, and examples include wood boards, inorganic boards, metal plates, composite boards made of a plurality of materials, etc. A primer layer 6, a concealment layer (not shown), etc. may be provided between the decorative sheet 1 and the substrate B as appropriate. The tensile elastic modulus of the decorative sheet 1 of the present embodiment, particularly the range of the tensile elastic modulus of the base material layer 2 alone, is preferably 850 MPa or more and 1600 MPa or less. If the tensile elastic modulus is less than 850 MPa, there is a risk that defects during printing cannot be suppressed. If the tensile elastic modulus exceeds 1600 MPa, due to excessive crystallinity, even when a nucleating agent (for example, nucleating agent vesicles) is used, there is a risk that defects such as whitening and cracking may occur during bending.

[0018] Next, each layer constituting the decorative sheet 1 will be described. <Base material layer 2> The base layer 2 consists of a colored polypropylene film. The colored polypropylene film is made primarily from polypropylene resin, which is colored by mixing inorganic pigments with the polypropylene resin. Furthermore, a nano-sized nucleating agent is added to the base layer 2 to increase its crystallinity. In this embodiment, the nano-sized nucleating agent may be added in the form of nucleating agent vesicles.

[0019] (Polypropylene resin) While it is preferable to use highly crystalline homopolypropylene, as described later, the polypropylene resin is not limited to highly crystalline homopolypropylene. In applications where processability, such as bending, is of paramount importance, the highly crystalline homopolypropylene can be mixed with, for example, a random polypropylene resin having an ethylene content within a predetermined range or a known amorphous polypropylene resin.

[0020] The peak intensity ratio x, calculated from the absorption spectrum obtained by Fourier-type infrared spectroscopy of the substrate layer 2 made of colored polypropylene film, is adjusted to be between 0.7 and 0.9. If the peak intensity ratio x is less than 0.7, it is highly likely that defects during printing and processing cannot be suppressed, and it will be difficult to ensure the scratch resistance required for practical use. On the other hand, if the peak intensity ratio x exceeds 0.9, the crystallinity is too high, and even when using nucleating agent vesicles, defects such as whitening and cracking may occur during bending.

[0021] Here, we will explain Fourier-type infrared spectroscopy. First, infrared spectroscopy is a measurement method that obtains information about the chemical structure and state of a substance by measuring the infrared light absorbed by the substance, which is infrared light with a wavelength of 2.5 μm to 25 μm, based on the vibration and rotational motion of the substance's molecules. Specifically, the measurement method involves irradiating the substance with infrared light from a light source, generating an interference wave by combining the separated transmitted light and reflected light, and measuring the infrared spectrum by calculating the intensity of each wavenumber component from the signal intensity of the interference wave. In particular, in this embodiment, the calculation of the interference wave was performed using the Fourier transform method, and the measurement was performed using Fourier-type infrared spectroscopy, which is a method of measuring the infrared spectrum. A graph plotting the wavenumber obtained by the above method on the horizontal axis and the measured absorbance (or transmittance) on the vertical axis is called an infrared absorption spectrum (or infrared transmission spectrum), and a unique pattern can be observed for each substance. In this case, the absorbance on the vertical axis changes in value at a given wavenumber in proportion to the concentration and thickness of the substance, and in the case of crystalline substances, the amount of crystalline or amorphous portion. Therefore, quantitative analysis can also be performed from the height and area of ​​the peak.

[0022] In this embodiment, the above-described characteristics of the infrared absorption spectrum are utilized to determine the absorbance of the crystalline portion of the colored polypropylene film in the absorption spectrum obtained by the aforementioned measurement, specifically the wavenumber 997 cm⁻¹. -1 The peak intensity and the absorbance of the amorphous portion of the film correspond to a wavenumber of 973 cm⁻¹. -1 The ratio of the peak intensity to the chromatic wave number, i.e., the peak intensity ratio x representing the degree of crystallinity of polypropylene, is calculated using the following formula. The relationship between this peak intensity ratio x and the rigidity of the colored polypropylene film is clarified, and a decorative sheet with excellent rigidity is provided by using a colored polypropylene film with a peak intensity ratio x within a predetermined range as the base layer. Note: wave number 997 cm. -1 Peak intensity and wavenumber 973cm -1 The peak intensities are, respectively, at wavenumber 938 cm⁻¹. -1 Background correction is performed using the peak intensity.

[0023]

number

[0024] Furthermore, it is important that the thickness of the base layer 2, which is made of colored polypropylene film, is between 50 μm and 150 μm. If the thickness of the substrate layer 2 is less than 50 μm, even if the peak intensity ratio x is within the optimal range, the film strength will be insufficient, making it difficult to suppress defects during printing and deterioration of scratch resistance. Yes. On the other hand, if the thickness of the base material layer 2 exceeds 150 μm, there is a risk of defects such as whitening or cracking occurring during bending. In this embodiment, it is preferable to use a highly crystalline polypropylene resin as the polypropylene resin. In particular, it is preferable to use a highly crystalline homopolypropylene resin, which is a propylene monopolymer with an isotactic pentad fraction (mmmm fraction) of 95% or more, in an amount of 50% to 100% by mass relative to the total mass of the polypropylene resin.

[0025] The crystallization temperature of polypropylene resin is generally considered to be in the range of 100 to 130°C, and when a nucleating agent is added, it is in the range of 110 to 140°C. In the colored polypropylene film of the decorative sheet 1 of this embodiment, the value of the peak intensity ratio x is adjusted to 0.7 or more and 0.9 or less by controlling the cooling time from the crystallization temperature within this range to the curing completion temperature using a known cooling process. Furthermore, if a polypropylene resin with an isotactic pentad fraction (mmmm fraction) of less than 95% is used, the crystallinity is insufficient, and even if the cooling process is controlled, the peak intensity ratio x may fall below the preferred range. Similarly, if the highly crystalline homopolypropylene resin is less than 50% by mass, the crystallinity is insufficient, and even if the cooling process is controlled, the peak intensity ratio x may fall below the preferred range.

[0026] Here, the isotactic pentad fraction (mmmm fraction) is calculated from a numerical value (electromagnetic wave absorption rate) obtained by resonating a resin material at a predetermined resonance frequency using 13C-NMR (nuclear magnetic resonance) measurement with carbon (C) of mass 13 (nuclide). It defines the atomic arrangement, electronic structure, and molecular microstructure of the resin material. In the case of crystalline polypropylene resin, the pentad fraction is the ratio of propylene units arranged in groups of five, 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 mainly determine the scratch resistance of the surface, and basically, a higher pentad fraction indicates a higher degree of crystallinity.

[0027] (Inorganic pigments) Inorganic pigments can be known inorganic pigments, such as titanium dioxide, which provides opacity. Examples of inorganic pigments for coloring include composite oxides such as iron-zinc, chromium-antimony, and iron-aluminum, as well as iron oxide, whose formulations can be freely adjusted according to the desired color. Furthermore, luminescent materials such as aluminum flakes and pearl pigments can also be added as inorganic pigments. Organic pigments, such as carbon black, may also be used in combination. Furthermore, additives such as fatty acid metal salts may be added to improve dispersibility and extrusion suitability.

[0028] (Nucleating agent vesicles) Furthermore, the base layer 2 contains a nano-sized nucleating agent. The nano-sized nucleating agent may be added to the polypropylene resin in the form of a nucleating agent vesicle, for example, which is encapsulated in a vesicle having a single-layer outer film. Because the base layer 2 contains a nucleating agent, its crystallinity can be improved, and the scratch resistance (scratch resistance) of the base layer 2 can be improved. In this embodiment, the nucleating agent in the resin constituting the base layer 2 may be encapsulated in a vesicle with a portion of the nucleating agent exposed. The nano-sized nucleating agent preferably has an average particle size of 1 / 2 or less of the wavelength range of visible light. Specifically, since the wavelength range of visible light is 400 nm to 750 nm, it is preferable that the average particle size be 375 nm or less.

[0029] Because nano-sized nucleating agents have extremely small particle sizes, the amount of nucleating agent present per unit volume is The number and surface area increase inversely proportional to the cube of the particle diameter. As a result, the distance between each nucleating agent particle becomes smaller, so when crystal growth occurs from the surface of one nucleating agent particle added to the polypropylene resin, the growing edge of the crystal immediately comes into contact with the edge of the crystal growing from the surface of another nucleating agent particle adjacent to that particle. The edges of the crystals inhibit each other's growth, stopping the growth of each crystal. Therefore, the average particle size of spherulites in the crystalline portion of the crystalline polypropylene resin can be reduced, for example, to 1 μm or less. As a result, a highly hard colored polypropylene film with a high degree of crystallinity can be produced, and the stress concentration between spherulites that occurs during bending is efficiently dispersed, making it possible to realize a colored polypropylene film that suppresses cracking and whitening during bending.

[0030] When a nucleating agent is simply added, the particle size increases due to secondary aggregation of the nucleating agent in the polypropylene resin, and the number of crystal nuclei relative to the amount of nucleating agent added may be less than when it is added as nucleating agent vesicles. As a result, the average particle size of spherulites in the crystalline part of the polypropylene resin increases, and cracking and whitening during bending tend to be less suppressed compared to when it is added as nucleating agent vesicles. Therefore, when a nucleating agent is simply added, it tends to be more difficult to achieve both improved elastic modulus due to increased crystallinity and improved processability compared to when it is added as nucleating agent vesicles.

[0031] In this embodiment, the base layer 2, which is made of a colored polypropylene film and constitutes the decorative sheet 1, preferably contains a nucleating agent (nucleating agent vesicles) in an amount of 0.01 parts by mass or more and 0.5 parts by mass or less, preferably 0.05 parts by mass or more and 0.3 parts by mass or less, relative to 100 parts by mass of polypropylene resin as the main component. If the amount of nucleating agent (nucleating agent vesicles) added is less than 0.01 parts by mass, the degree of crystallinity may not improve sufficiently, and the required elastic modulus (hardness) may not be reached. If the amount added exceeds 0.5 parts by mass, the crystal nuclei will be excessive, which will inhibit spherulite growth, and as a result, the degree of crystallinity may not improve sufficiently, and the required elastic modulus (hardness) may not be reached.

[0032] Furthermore, as methods for nano-sizing nucleating agents, appropriate methods can be used, such as solid-phase methods that obtain nano-sized particles by mainly mechanically grinding the nucleating agent; liquid-phase methods that synthesize or crystallize nano-sized particles in the nucleating agent or a solution in which the nucleating agent is dissolved; and gas-phase methods that synthesize or crystallize nano-sized particles from the nucleating agent or a gas / vapor composed of the nucleating agent. Examples of solid-phase methods include ball mills, bead mills, rod mills, colloid mills, conical mills, disc mills, hammer mills, and jet mills. Examples of liquid-phase methods include crystallization, coprecipitation, sol-gel, liquid-phase reduction, and hydrothermal synthesis. Examples of gas-phase methods include electric furnaces, chemical flames, lasers, and thermal plasmas.

[0033] As a method for nano-sizing nucleating agents, supercritical reverse-phase evaporation is preferred. Supercritical reverse-phase evaporation is a method for producing capsules (nano-sized vesicles) containing the target substance using carbon dioxide in a supercritical state or under temperature or pressure conditions above the critical point. Supercritical carbon dioxide refers to carbon dioxide in a supercritical state above the critical temperature (30.98°C) and critical pressure (7.3773±0.0030 MPa), while carbon dioxide under temperature or pressure conditions above the critical point refers to carbon dioxide under conditions where only the temperature or only the pressure exceeds the critical conditions.

[0034] Furthermore, as a specific nano-processing method using supercritical reverse-phase evaporation, first, an aqueous phase is injected into a mixed fluid of supercritical carbon dioxide, phospholipid as an outer film-forming material, and a nucleating agent as an encapsulating material, and the mixture is stirred to generate an emulsion of supercritical carbon dioxide and the aqueous phase. Next, by reducing the pressure, the carbon dioxide expands and evaporates, causing a phase inversion, and generating nanocapsules (nanovesicles) in which the phospholipid covers the surface of the nucleating agent particles with a single-layer film. By using this supercritical reverse-phase evaporation method, unlike conventional encapsulation methods in which the outer film on the surface of the nucleating agent particles becomes a multi-layer film, it is possible to easily generate single-layer capsules, thus enabling the preparation of smaller diameter capsules. Furthermore, nucleating agent vesicles can be prepared by methods such as the Bangham method, extrusion method, hydration method, surfactant dialysis method, reverse-phase evaporation method, freeze-thaw method, and supercritical reverse-phase evaporation method. Among these, the supercritical reverse-phase evaporation method is particularly preferred. The outer membrane constituting the nucleating agent vesicle is composed of, for example, a single layer membrane. Furthermore, this outer membrane is composed of, for example, a substance containing biolipids such as phospholipids.

[0035] In this specification, nucleating agent vesicles whose outer membrane is composed of a substance containing biolipids such as phospholipids are referred to as nucleating agent liposomes. Examples of phospholipids that make up the outer membrane include glycerophospholipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, cardiopine, egg yolk lecithin, hydrogenated egg yolk lecithin, soy lecithin, and hydrogenated soy lecithin, as well as sphingophospholipids such as sphingomyelin, ceramide phosphorylethanolamine, and ceramide phosphorylglycerol.

[0036] Other substances that form the outer film of the vesicle include, for example, nonionic surfactants and dispersants such as mixtures thereof with cholesterols or triacylglycerols. Among these, one or more nonionic surfactants can be used, such as polyglycerin ether, dialkylglycerin, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ether, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxyethylene polyoxypropylene copolymer, polybutadiene-polyoxyethylene copolymer, polybutadiene-poly2-vinylpyridine, polystyrene-polyacrylic acid copolymer, polyethylene oxide-polyethylethylene copolymer, and polyoxyethylene-polycaprolactam copolymer. Cholesterols can be, for example, cholesterol, α-cholestanol, β-cholestanol, cholestan, desmosterol (5,24-cholestadiene-3β-ol), sodium cholate, or cholecalciferol.

[0037] Furthermore, the outer membrane of the liposome may be formed from a mixture of phospholipid and a dispersant. In the decorative sheet 1 of this embodiment, it is preferable to use radical scavenger liposomes having an outer membrane made of phospholipid as the nucleating agent vesicle, and by making the outer membrane from phospholipid, the compatibility between the resin material, which is the main component of the substrate layer 2, and the vesicle can be improved.

[0038] The nucleating agent is not particularly limited as long as it is a substance that acts as a starting point for crystallization when the resin crystallizes. Examples of nucleating agents include metal phosphate salts, metal benzoate salts, metal pimephosphate salts, metal rosin salts, benzylidene sorbitol, quinacridone, cyanine blue, and talc. In particular, to maximize the effect of the nano-processing, it is preferable to use metal phosphate salts, metal benzoate salts, metal pimephosphate salts, and metal rosin salts, which are non-melting types and can be expected to have good transparency. However, if the transparency of the material itself can be achieved by the nano-processing, colored quinacridone, cyanine blue, and talc can also be used. In addition, molten benzylidene sorbitol may be appropriately mixed with the non-melting nucleating agent.

[0039] As described above, one of the features (specific features of the invention) of the decorative sheet 1 of this embodiment is that "the base layer 2 contains a nucleating agent encapsulated in vesicles." By adding the nucleating agent to the resin composition while it is encapsulated in vesicles, the dispersibility of the nucleating agent in the resin material, i.e., in the base layer 2, is dramatically improved. This feature is achieved in the finished decorative sheet 1. Directly identifying the material based on its structure and properties in the state of sheet 1 is impractical, as it may be difficult depending on the circumstances. The reason is as follows: The nucleating agent added in the form of vesicles is dispersed with high dispersibility, and even in the state of the manufactured decorative sheet 1, the nucleating agent is highly dispersed in the base layer 2. However, in the manufacturing process of decorative sheet 1, after the base layer 2 is manufactured by adding the nucleating agent in the form of vesicles to the resin composition constituting the base layer 2, various treatments such as compression and hardening treatments are usually performed on the laminate. However, such treatments may cause the outer membrane of the vesicles containing the nucleating agent to be crushed or chemically reacted, making it highly possible that the nucleating agent is not contained (encased) by the outer membrane. Furthermore, the state of crushing or chemical reaction of the outer membrane varies depending on the processing steps of the decorative sheet 1. Furthermore, in situations where the nucleating agent is not contained within the outer film, it is difficult to specify the physical properties themselves within a numerical range. It is also conceivable that it may be difficult to determine whether the constituent material of the crushed outer film is the outer film of the vesicles or a material added separately from the nucleating agent. Thus, although the present invention differs from the conventional invention in that the nucleating agent is blended in a highly dispersed manner within the substrate layer 2, it is conceivable that it may be impractical to determine, based on measurements and analysis of the structure and properties of the decorative sheet 1, whether the nucleating agent was added in the form of vesicles containing it, within a numerical range. Here, the nucleating agent vesicle with the above configuration may also be included in the transparent resin layer 4 and the topcoat layer 5.

[0040] (Pattern layer 3) A pattern layer 3 can be provided on the surface of the colored polypropylene film (base layer 2) to add a pattern to the decorative sheet 1. Examples of patterns that can be used include wood grain, stone, sand, tile, brick, fabric, leather, and geometric shapes. Furthermore, a solid undercoat ink layer (not shown) may be provided between the base layer 2 and the pattern layer 3, depending on the desired degree of design. The solid undercoat ink layer is provided so as to cover the entire surface of the base layer 2. The solid undercoat ink layer may also be made up of two or more layers as needed for opacity, etc. Furthermore, the pattern layer 3 may be formed by laminating as many layers as necessary to express the desired design. Thus, the pattern layer 3 and the solid undercoat ink layer can be in various combinations depending on the desired design, that is, the design to be expressed, but are not particularly limited.

[0041] The constituent materials of the base solid ink layer and the pattern layer 3 are not particularly limited. For example, printing inks and coating agents can be used, which are obtained by dissolving and dispersing a matrix and a coloring agent such as a dye or pigment in a solvent. As the matrix, for example, various synthetic resins such as oily nitrite resin, two-component urethane resin, acrylic resin, styrene resin, polyester resin, urethane resin, polyvinyl resin, alkyd resin, epoxy resin, melamine resin, fluororesin, silicone resin, rubber resin, or mixtures or copolymers thereof can be used. As the coloring agent, for example, inorganic pigments such as carbon black, titanium white, zinc oxide, iron oxide, yellow lead, Prussian blue, and cadmium red, or organic pigments such as azo pigments, lake pigments, anthraquinone pigments, phthalocyanine pigments, isoindolinone pigments, and dioxazine pigments, or mixtures thereof can be used. Furthermore, as solvents, for example, toluene, xylene, ethyl acetate, butyl acetate, methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, water, or mixtures thereof can be used.

[0042] Furthermore, functional additives such as extender pigments, plasticizers, dispersants, surfactants, tackifiers, adhesion aids, drying agents, curing agents, curing accelerators, and curing retarders may be added to the base solid ink layer and the pattern layer 3 in order to impart various functions. Here, the base solid ink layer and the pattern layer 3 are, for example, gravure printing, offset printing The layers can be formed by various printing methods such as screen printing, electrostatic printing, and inkjet printing. Furthermore, since the base solid ink layer covers the entire surface of the substrate layer 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 them all at once.

[0043] (Transparent resin layer 4) The resin material used as the main component of the transparent resin layer 4 is preferably an olefin-based resin, and in addition to polypropylene, polyethylene, and polybutene, 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-pentene) Examples include monopolymers or copolymers of two or more types of polypropylene (such as 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene), 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, and ethylene-butyl acrylate copolymer. Furthermore, to improve the surface strength of the decorative sheet 1, it is preferable to use a highly crystalline polypropylene resin, similar to the base layer 2. Here, in this specification, the main component refers to 90% or more by mass of the material in question, unless otherwise specified.

[0044] When a transparent resin layer 4 is provided, the thickness of the transparent resin layer 4 is preferably 50 μm or more and 100 μm or less. If it is less than 50 μm, the effect of improving the scratch resistance of the surface of the transparent resin layer 4 is low, and the significance of providing the transparent resin layer 4 may be diminished. If it exceeds 100 μm, the rigidity of the decorative sheet 1 is too high, and defects such as whitening and cracking may occur during bending. However, if a topcoat layer 5 is provided on top of the transparent resin layer 4, the thickness of the transparent resin layer 4 may be less than 50 μm. Furthermore, the resin composition constituting the transparent resin layer 4 may contain various functional additives as needed, such as heat stabilizers, light stabilizers, blocking inhibitors, catalyst scavengers, colorants, light scattering agents, and gloss modifiers. These various functional additives can be appropriately selected from well-known sources.

[0045] (Top coat layer 5) If further improvement in scratch resistance or adjustment of gloss is required, a topcoat layer 5 can be provided on the surface of the transparent resin layer 4. The main component resin material for the top coat layer 5 can be appropriately selected from, for example, polyurethane-based, acrylic silicone-based, fluorine-based, epoxy-based, vinyl-based, polyester-based, melamine-based, amino alkyd-based, and urea-based resin materials. The form of the resin material is not particularly limited and can be aqueous, emulsion-based, solvent-based, etc. The curing method can also be appropriately selected from one-component type, two-component type, ultraviolet curing method, etc.

[0046] As the main component of the top coat layer 5, the resin material used is an isocyanate. Urethane-based curing agents are preferred from the viewpoints of workability, cost, and the cohesive strength of the resin itself. For isocyanates, curing agents such as adducts, burettes, 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(isocyanate-methyl)cyclohexane (HXDI), and trimethylhexamethylene diisocyanate (TMDI), can be appropriately selected and used. However, considering weather resistance, curing agents based on hexamethylene diisocyanate (HMDI) or isophorone diisocyanate (IPDI), which have a linear molecular structure, are preferred. In addition, if surface hardness is to be improved, it is preferable to use a resin that cures with active energy rays such as ultraviolet light or electron beams. Furthermore, these resins can be used in combination with each other. For example, by using a hybrid type combining a thermosetting resin and a photocuring resin, it is possible to improve surface hardness, suppress curing shrinkage, and enhance adhesion.

[0047] A gloss adjuster can be added to the top coat layer 5 to adjust the gloss. Any commercially available, well-known gloss adjuster can be used. For example, fine particles made of inorganic materials such as silica, glass, alumina, calcium carbonate, or barium sulfate may be used. Alternatively, fine particles made of organic materials such as acrylic may be used. However, if high transparency is required, it is desirable to use fine particles of silica, glass, acrylic, etc., which have high transparency. In particular, among fine particles of silica, glass, etc., gloss adjusters with low bulk density, which are not solid spherical particles but rather fine primary particles that have undergone secondary aggregation, 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.

[0048] Furthermore, functional additives such as antibacterial agents and antifungal agents may be added to the topcoat layer 5 to impart various functions. UV absorbers and light stabilizers may also be added as needed. Examples of UV absorbers include benzotriazole, benzoate, benzophenone, triazine, and cyanoacrylate types. Hindered amine types can be used as light stabilizers. The thickness of the topcoat layer 5 is preferably between 3 μm and 15 μm. If it is less than 3 μm, the effect of improving scratch resistance is low, and the significance of providing the topcoat layer 5 may be diminished. If it exceeds 15 μm, cracks or breaks may occur during bending, which may cause design problems or deterioration of weather resistance.

[0049] <Manufacturing method> This section describes an example of the manufacturing process for decorative sheet 1. A nucleating agent is encapsulated within a vesicle to create a nucleating agent vesicle, and this nucleating agent vesicle is then added to a polypropylene resin along with an inorganic pigment to produce a resin material for the substrate layer. The nucleating agent vesicles are prepared, for example, by encapsulating the nucleating agent within a vesicle having a single layer film using supercritical reverse-phase evaporation. It is preferable to use highly crystalline homopolypropylene resin with an isotactic pentad fraction (mmmm fraction) of 95% or more of the polypropylene resin used, which accounts for 50% to 100% by mass of the resin.

[0050] The resin material for the base layer described above is heated and melted, and then formed into a sheet with a thickness of 50 μm to 150 μm by extrusion molding or the like to form the base layer 2. At this time, by adjusting the cooling time from the crystallization temperature to the curing completion temperature using a known adjustment method, the value of the peak intensity ratio x calculated from the absorption spectrum obtained in the Fourier infrared spectroscopy measurement of the substrate layer 2 is controlled to be between 0.7 and 0.9. Furthermore, if necessary, a pattern layer 3 is formed on the upper surface of the base layer 2 by printing, and a transparent layer is placed on top of it. At least one of the resin layer 4 and the topcoat layer 5 is formed by printing. Although the above manufacturing method describes the case in which the substrate layer 2 is manufactured using nucleating agent vesicles, the present invention is not limited thereto. For example, the substrate layer 2 may be manufactured by replacing the nucleating agent vesicles with nano-sized nucleating agents that are not encapsulated in vesicles.

[0051] <Functions and other effects> (1) The decorative sheet 1 of this embodiment has a base layer 2 made of a colored polypropylene film obtained by mixing an inorganic pigment with a polypropylene resin, the base layer 2 contains a nano-sized nucleating agent, the thickness of the base layer 2 is 50 μm or more and 150 μm or less, and the value of the peak intensity ratio x calculated from the absorption spectrum obtained by Fourier infrared spectroscopy is 0.7 or more and 0.9 or less. In addition, the tensile modulus of the base layer 2 is 850 MPa or more and 1600 MPa or less. According to this configuration, by adding a nucleating agent that improves the crystallinity of polypropylene, and further optimizing the value of the peak intensity ratio x calculated from the absorption spectrum obtained by Fourier infrared spectroscopy, as well as the film thickness, it is possible to provide a decorative sheet 1 that achieves both printability (resistance to stretching, etc.), scratch resistance, and flexibility.

[0052] (2) In this embodiment, it is preferable that 50% to 100% by mass of the polypropylene resin constituting the base layer 2 of the decorative sheet 1 consists of a highly crystalline homopolypropylene resin with an isotactic pentad fraction (mmmm fraction) of 95% or more. This configuration makes it possible to more reliably adjust the peak intensity ratio x, calculated from the absorption spectrum obtained in Fourier-type infrared spectroscopy, to be between 0.7 and 0.9.

[0053] (3) In this embodiment, it is preferable that the amount of nucleating agent added to the base layer 2 of the decorative sheet 1 is 0.05 parts by mass or more and 0.5 parts by mass or less per 100 parts by mass of polypropylene resin. With this configuration, the degree of crystallinity of the colored polypropylene constituting the base layer 2 is sufficiently improved, ensuring that the required tensile modulus of elasticity of 850 MPa to 1600 MPa is reliably secured.

[0054] (4) In this embodiment, the decorative sheet 1 is preferably a nucleating agent vesicle in which the nucleating agent is encapsulated in a vesicle having a single-layer outer membrane. According to this configuration, a nucleating agent that improves the crystallinity of polypropylene is vesicled and added as nucleating agent vesicles, and by further optimizing the value of the peak intensity ratio x calculated from the absorption spectrum obtained by Fourier infrared spectroscopy, and the film thickness, it is possible to provide a decorative sheet 1 that can achieve both printability (resistance to stretching, etc.), scratch resistance, and bendability.

[0055] (5) The decorative sheet 1 of this embodiment is preferably formed by adding nucleating agent vesicles to 100 parts by mass of polypropylene resin in an amount of 0.05 parts by mass or more and 0.5 parts by mass or less when converted to nucleating agent in the nucleating agent vesicles. According to this configuration, a nucleating agent that improves the crystallinity of polypropylene is vesicled and added as nucleating agent vesicles, and by further optimizing the value of the peak intensity ratio x calculated from the absorption spectrum obtained by Fourier infrared spectroscopy, and the film thickness, it is possible to provide a decorative sheet 1 that can achieve both printability (resistance to stretching, etc.), scratch resistance, and bendability.

[0056] (6) In this embodiment, it is preferable that the amount of nucleating agent vesicles added to the base layer 2 of the decorative sheet 1 is 0.05 parts by mass or more and 0.5 parts by mass or less in terms of nucleating agent in the nucleating agent vesicles, per 100 parts by mass of polypropylene resin. With this configuration, the degree of crystallinity of the colored polypropylene constituting the base layer 2 is sufficiently improved. This ensures that the required tensile modulus of elasticity between 850 MPa and 1600 MPa is reliably secured.

[0057] (7) In this embodiment, the decorative sheet 1 is preferably a nucleating agent vesicle which is a nucleating agent liposome having an outer membrane made of phospholipids. This configuration allows for good compatibility between the resin material, which is the main component of the base layer 2, and the vesicles. (8) In this embodiment, it is preferable that the decorative sheet 1 has a pattern layer 3 laminated on one side of the base layer 2. This configuration makes it possible to improve the aesthetic appeal of the decorative sheet 1. (9) In this embodiment, it is preferable that the decorative sheet 1 has at least one of the transparent resin layer 4 and the top coat layer 5 laminated on one side of the base layer 2.

[0058] [Examples] The following describes a specific example of the decorative sheet 1 of this embodiment. (Method for manufacturing nucleating agent vesicles) First, the method for producing the nucleating agent liposomes used in this embodiment will be explained. The nucleating agent liposomes were prepared using the aforementioned supercritical reverse-phase evaporation method. 100 parts by mass of methanol, 70 parts by mass of a phosphate ester metal salt nucleating agent (ADEKA Stab NA-21; manufactured by ADEKA), and 5 parts by mass of phosphatidylcholine as a phospholipid constituting the outer membrane of the vesicle were placed in a sealed, high-pressure stainless steel container maintained at 60°C. Carbon dioxide was then injected into the container to create a supercritical state, bringing the pressure to 20 MPa. Subsequently, the contents of the container were vigorously stirred, and 100 parts by mass of ion-exchanged water were added. After further stirring and mixing for 15 minutes while maintaining the temperature and pressure in a supercritical state, carbon dioxide was released from the container to return to atmospheric pressure, thereby obtaining nucleating agent vesicles containing the nucleating agent within a vesicle having a single-layer outer membrane made of phospholipid.

[0059] (Example 1) As a raw material for the colored polypropylene film, 78 parts by mass of highly crystalline homopolypropylene resin with a pentad fraction of 97.8%, a melt flow rate (MFR) of 15 g / 10 min (230°C), and a molecular weight distribution MWD (Mw / Mn) of 2.3 was mixed with 6 parts by mass of titanium dioxide pigment, 16 parts by mass of chromium-antimony composite oxide pigment, and 0.01 parts by mass of the aforementioned nucleating agent vesicle as a nucleating agent. A substrate layer 2 consisting of a colored polypropylene film with a thickness of 55 μm was produced by extrusion molding using a melt extruder. (Example 2) Except for adding the aforementioned nucleating agent vesicles as a nucleating agent in an amount of 0.5 parts by mass, a substrate layer 2 with a thickness of 55 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 1.

[0060] (Example 3) As raw materials for the colored polypropylene film, 39 parts by mass of highly crystalline homopolypropylene resin with a pentad fraction of 97.8%, a melt flow rate (MFR) of 15 g / 10 min (230°C), and a molecular weight distribution MWD (Mw / Mn) of 2.3 were mixed with 39 parts by mass of random polypropylene resin with a melt flow rate (MFR) of 12 g / 10 min (230°C) containing 4% ethylene, 6 parts by mass of titanium dioxide pigment and 16 parts by mass of chromium-antimony composite oxide pigment as inorganic pigments, and the above-mentioned nucleating agent vesicle was added in a nucleating agent amount of 0.01 parts by mass. A base layer 2 consisting of a colored polypropylene film with a thickness of 55 μm was produced by extrusion molding using a melt extruder.

[0061] (Example 4) The above-mentioned nucleating agent vesicle was added as a nucleating agent in an amount of 0.5 parts by mass, except that this is the example. Similar to step 3, a substrate layer 2 with a thickness of 55 μm was formed by extrusion molding using a melt extruder. (Example 5) Similar to Example 1, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder. (Example 6) Similar to Example 2, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder. (Example 7) Similar to Example 3, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder. (Example 8) Similar to Example 4, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder.

[0062] (Example 9) A pattern layer 3 was formed by printing a pattern onto the surface of a 55 μm thick substrate layer 2, which was prepared in the same manner as in Example 1. The pattern layer 3 was formed using an ink prepared by adding 0.5 parts by mass of a hindered amine-based light stabilizer (Kimasorb 944; manufactured by BASF) to a two-component urethane ink (V180; manufactured by Toyo Ink Co., Ltd.) relative to the binder resin component of the ink. In addition, a primer layer 6 was formed on the back surface of the substrate layer 2. The primer layer 6 was formed by printing the same two-component urethane ink as the pattern layer 3. Next, a mixture prepared by mixing 100 parts by mass of crystalline polypropylene resin (pentad fraction 97.8%, molecular weight distribution 2.3, MFR 18g / 10min) with 0.5 parts by mass of a hindered amine-based light stabilizer (BASF's "Kimasorb 944") and 0.5 parts by mass of a benzotriazole-based ultraviolet absorber (BASF's "Tinuvin 328") was co-extruded with a polyethylene-based easy-adhesion resin using a melt extruder to form a transparent resin layer 4 with a thickness of 60 μm and an adhesive resin layer 4b with a thickness of 10 μm. Then, a dry laminating adhesive (Takelac A540; manufactured by Mitsui Chemicals, Inc.; application amount 2g / m²) was applied to the surface of the substrate on which the pattern layer 3 was formed. 2 A coating was applied. Subsequently, the pattern layer 3 of the substrate to which the adhesive was applied and the transparent resin layer 4 were bonded together by extrusion lamination via the formed adhesive resin layer 4b. Furthermore, an embossed pattern 4a was applied to the transparent resin layer 4 side of the bonded sheet by pressing it with an embossing die roll, and then a two-component curing urethane topcoat (DIC Graphics "W184") was applied to the embossed pattern 4a surface at a rate of 3g / m². 2 The material was then applied to form a topcoat layer 5. In this way, the decorative sheet 1 shown in Figure 2 was obtained.

[0063] (Example 10) A transparent resin layer 4 and a top coat layer 5 were formed on a substrate layer 2 with a thickness of 55 μm, which was prepared in the same manner as in Example 2, in the same manner as in Example 9, to obtain a decorative sheet 1. (Example 11) A transparent resin layer 4 and a topcoat layer 5 were formed on a substrate layer 2 with a thickness of 55 μm, which was prepared in the same manner as in Example 3, in the same manner as in Example 9, to obtain a decorative sheet 1. (Example 12) A transparent resin layer 4 and a top coat layer 5 were formed on a substrate layer 2 with a thickness of 55 μm, which was prepared in the same manner as in Example 4, in the same manner as in Example 9, to obtain a decorative sheet 1.

[0064] (Example 13) A transparent resin layer 4 and a topcoat layer 5 were formed on a substrate layer 2 with a thickness of 145 μm, which was prepared in the same manner as in Example 5, in the same manner as in Example 9, to obtain a decorative sheet 1. (Example 14) A 145 μm thick substrate layer 2, prepared in the same manner as in Example 6, was subjected to a transparent coating, similar to that in Example 9. A resin layer 4 and a top coat layer 5 were formed to obtain a decorative sheet 1. (Example 15) A transparent resin layer 4 and a topcoat layer 5 were formed on a substrate layer 2 with a thickness of 145 μm, which was prepared in the same manner as in Example 7, in the same manner as in Example 9, to obtain a decorative sheet 1. (Example 16) A transparent resin layer 4 and a topcoat layer 5 were formed on a substrate layer 2 with a thickness of 145 μm, which was prepared in the same manner as in Example 8, in the same manner as in Example 9, to obtain a decorative sheet 1.

[0065] (Example 17) Except for using a nucleating agent without an outer film instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 7. (Example 18) Except for using a nucleating agent without an outer film instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 145 μm was produced by extrusion molding using a melt extruder, in the same manner as in Example 8. (Example 19) Except for using a nucleating agent without an outer film instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 145 μm was fabricated by extrusion molding using a melt extruder, in the same manner as in Example 5. (Example 20) Except for using a nucleating agent without an outer film instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 6.

[0066] (Comparative Example 1) Except for using the untreated nucleating agent instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 55 μm was produced by extrusion molding using a melt extruder, in the same manner as in Example 1. (Comparative Example 2) Except for using the untreated nucleating agent instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 55 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 2. (Comparative Example 3) Except for using an untreated nucleating agent instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 55 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 3. (Comparative Example 4) Except for using the untreated nucleating agent instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 55 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 4.

[0067] (Comparative Example 5) Except for using the untreated nucleating agent instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 5. (Comparative Example 6) Except for using the untreated nucleating agent instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 6. (Comparative Example 7) Except for using the untreated nucleating agent instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 7. (Comparative Example 8) Except for using the untreated nucleating agent instead of the nucleating agent vesicles described above, a substrate layer 2 with a thickness of 145 μm was formed by extrusion molding using a melt extruder, in the same manner as in Example 8.

[0068] (Comparative Example 9) Similar to Comparative Example 2, a substrate layer 2 with a thickness of 155 μm was formed by extrusion molding using a melt extruder. Then, a transparent resin layer 4 and a top coat layer 5 were formed in the same manner as in Example 9, and a decorative sheet was formed. I obtained T1. (Comparative Example 10) Similar to Example 2, a substrate layer 2 with a thickness of 155 μm was formed by extrusion molding using a melt extruder. Then, a transparent resin layer 4 and a top coat layer 5 were formed in the same manner as in Example 9 to obtain a decorative sheet 1. (Comparative Example 11) Similar to Example 2, a substrate layer 2 with a thickness of 45 μm was formed by extrusion molding using a melt extruder.

[0069] (Comparative Example 12) As raw materials for the colored polypropylene film, 31.2 parts by mass of highly crystalline homopolypropylene resin with a pentad fraction of 97.8%, a melt flow rate (MFR) of 15 g / 10 min (230°C), and a molecular weight distribution MWD (Mw / Mn) of 2.3 was mixed with 46.8 parts of random polypropylene resin with a melt flow rate (MFR) of 12 g / 10 min (230°C) containing 4% ethylene, 6 parts by mass of titanium dioxide pigment and 16 parts by mass of chromium-antimony composite oxide pigment as inorganic pigments, and 0.5 parts by mass of the aforementioned nucleating agent vesicle as a nucleating agent. A base layer 2 consisting of a colored polypropylene film with a thickness of 55 μm was produced by extrusion molding using a melt extruder.

[0070] (Comparative Example 13) As a raw material for the colored polypropylene film, 39 parts by mass of a highly crystalline homopolypropylene resin with a pentad fraction of 97.8%, a melt flow rate (MFR) of 15 g / 10 min (230 °C), and a molecular weight distribution MWD (Mw / Mn) of 2.3, 39 parts of a random polypropylene resin with a melt flow rate (MFR) of 12 g / 10 min (230 °C) containing 4% ethylene component, 6 parts by mass of titanium oxide pigment as an inorganic pigment, 16 parts by mass of a chromium-antimony composite oxide pigment, and 1.0 part by mass of the above-mentioned nucleating agent vesicle as a nucleating agent were added, and extrusion molding was performed using a melt extruder to produce a base material layer 2 made of a colored polypropylene film with a thickness of 55 μm.

[0071] (Evaluation) For the above Examples 1 to 20 and Comparative Examples 1 to 13, Fourier transform infrared spectroscopy measurement, measurement of tensile modulus, evaluation of defects (printing process suitability) during printing, scratch resistance, bending process suitability, and wrapping process smoothness (surface uniformity during wrapping process) were carried out. <Fourier transform infrared spectroscopy measurement> For Fourier transform infrared spectroscopy measurement, a Fourier transform infrared spectroscopy measurement device (Spectrum Spotlight 400) manufactured by PerkinElmer was used to obtain an absorption spectrum from 4000 cm -1 to 700 cm -1 From the obtained absorption spectrum, the peak intensity ratios at wave numbers 997 cm -1 , 973 cm -1 , and 938 cm -1 were extracted, and the peak intensity ratio x was calculated by the following formula.

[0072] [Number]

[0073] <Tensile modulus> For the measurement of tensile modulus, an autograph (AGS-500NX) manufactured by Shimadzu Corporation was used to conduct a tensile test at a tensile speed of 50 mm / min, and the tensile modulus was calculated. <Defects during printing (printing process suitability)> The pattern layer 3 was formed by gravure printing using a gravure printing press. During this process, the base material layer 2 stretched due to tension, and any misalignment of registration during the lamination of each color was evaluated as a printing defect. "◎" indicates that no registration adjustment is necessary, "○" indicates that adjustment can be easily performed using automatic registration adjustment, "△" indicates that careful registration adjustment is required, and "×" indicates that registration adjustment is impossible and printing cannot be continued. "×" also indicates that the film breaks frequently during printing, causing problems with mass production. A rating of "△" or higher indicates that the printing process is acceptable.

[0074] <Scratch resistance> Scratch resistance was evaluated by conducting a pencil hardness test. In the pencil hardness test, a 3B pencil was used, and the angle of the pencil to the decorative sheet 10 was fixed at 45±1°. A load of 750 kg was applied to the pencil, and the surface condition of the decorative sheet 10 was observed while it was slid (in accordance with the old JIS standard JIS K5400). The test was performed five times, and the pencil scratches and marks were evaluated. "◎" indicates no scratches or marks at all, "○" indicates slight pencil marks, "△" indicates visible pencil marks, and "×" indicates pencil scratches or tears in the colored polypropylene film. A rating of "○" or higher indicates no practical problems. A rating of "△" or higher also indicates no problems, although its use is limited to applications such as furniture or high vertical surfaces that are not easily touched. A rating of "○" or higher is preferable.

[0075] <Suitability for bending processes> In the bending suitability test, each decorative sheet 1 obtained by the above method in Examples 1 to 20 and Comparative Examples 1 to 13 was attached to one side of a medium-density fiberboard (MDF) as the base layer 2 using a urethane-based adhesive. On the other side of the base layer 2, a V-shaped groove was made up to the boundary where the base layer 2 and the decorative sheet 1 were bonded, so as not to damage the decorative sheet 1 on the opposite side. Next, the base layer 2 was bent 90 degrees along the V-shaped groove so that the surface of the decorative sheet 1 was folded inwards. The state of bending suitability was evaluated by observing the folded portion of the surface of the decorative sheet 1 using an optical microscope to check for whitening, cracks, etc. "◎" indicates no whitening or cracking at all, "○" indicates slight whitening in some areas, "△" indicates some whitening, and "×" indicates whitening throughout or some cracking. A rating of "△" or higher indicates no practical problems.

[0076] <Surface uniformity during wrapping process> In the surface uniformity test during the wrapping process, a rectangular timber was used as the base layer 2, consisting of 3 to 5 sheets of board material or particleboard laminated between two sheets of medium-density fiberboard (MDF). Each decorative sheet 1 obtained in Examples 1 to 20 and Comparative Examples 1 to 13, obtained by the above method, was attached to the decorative panel using hot-melt adhesive through a wrapping process. Subsequently, the surface where the decorative sheet 1 was attached to the edge of the board material was observed visually to check for surface irregularities caused by unevenness in the board material or steps at the bonded parts of the board material. Furthermore, the obtained decorative panel was left in an environment of 80°C and 85% humidity for 1000 hours, and the surface irregularities and peeling of the decorative sheet 1 in the same area were checked. A rating of "◎" indicates that the surface is completely smooth with no bumps or unevenness visible initially or after 1000 hours. A rating of "○" indicates that the surface appears slightly rough. A rating of "△" indicates that some bumps or unevenness are visible in certain areas. A rating of "×" indicates that bumps or unevenness are visible throughout the entire surface, or that the decorative sheet 10 has peeled off after 1000 hours. While a rating of "△" or higher is acceptable for practical use, a rating of "○" or higher is preferable. These evaluation results are shown in Table 1.

[0077] [Table 1]

[0078] As can be seen from Table 1, in the decorative sheet 1 of Examples 1-8 and 17-20, during printing and processing... It can be seen that the material is able to withstand practical use while ensuring sufficient durability and strength, and that bending is also possible. Furthermore, the decorative sheet 1 in Examples 9 to 16 has a pattern layer 3, a transparent resin layer 4, and a top coat layer 5 laminated on top of Examples 1 to 9, and it can be seen that it is able to achieve both high design and high scratch resistance while also being able to be bent.

[0079] On the other hand, in the decorative sheet 1 of Comparative Examples 1 to 9, since a non-vesicle-formed micro-sized nucleating agent was used, the improvement in strength due to the improvement in crystallinity was insufficient, and defects occurred during printing and processing, especially when the film thickness was thin and the blending ratio of highly crystalline homopolypropylene resin was low. Furthermore, even when there were no defects during printing and processing, some decorative sheets 1 lacked the required strength or exhibited defects during bending. These are thought to be due to the lower ability to improve crystallinity and the relatively larger spherulite size compared to vesicle-formed nucleating agents.

[0080] Furthermore, in the decorative sheets 1 of Comparative Examples 10 to 13, at least one of the film thickness of the base layer 2 and the peak intensity x exceeds the numerical range specified in this application, and it can be seen that at least one of the evaluation results is problematic. In Comparative Example 11, although automatic registration adjustment was possible, the film frequently broke during printing, making it impossible to produce a product. This is thought to be because, although the peak strength x and tensile modulus were sufficient, the film was too thin, and therefore could not withstand the tension fluctuations during printing, resulting in a high frequency of breakage.

[0081] From the above, it has become clear that the decorative sheets 1 of Examples 1 to 20 are decorative sheets that achieve a balance of all three aspects: printability (suitability for printing), scratch resistance, and flexibility. Furthermore, it has become clear that the decorative sheets 1 of Examples 1 to 20 also possess smoothness for wrapping. Furthermore, the decorative sheet of the present invention is not limited to the above embodiments and examples, and various modifications are possible as long as they do not impair the features of the invention. [Explanation of Symbols]

[0082] 1…Decorative sheet, 2…Base layer, 3…Pattern layer, 4…Transparent resin layer, 4a…Embossed pattern, 4b…Adhesive resin layer, 5…Top coat layer, 6…Primer layer, B…Substrate

Claims

1. The material has a base layer made of a colored polypropylene film obtained by mixing an inorganic pigment with a polypropylene resin, the base layer contains a nano-sized nucleating agent, the thickness of the base layer is 50 μm or more and 150 μm or less, and the value of the peak intensity ratio x calculated using the following formula 1 from the absorption spectrum obtained by Fourier infrared spectroscopy is 0.7 or more and 0.9 or less. The above substrate layer further contains a fatty acid metal salt as an additive. The above inorganic pigments include titanium dioxide and iron oxide, or contain titanium dioxide alone. The above nucleating agent comprises a non-melting type nucleating agent and a melting type nucleating agent. The above-mentioned molten nucleating agent is benzylidenesorbitol, and the decorative sheet is characterized in this respect. Here, in the following equation, I ９９７ Wave number 997 cm －１ Peak intensity value, I ９３８ Wave number 938 cm －１ Peak intensity value, I ９７３ Wave number 973 cm －１ This shows the peak intensity value. [Math 1]

2. The decorative sheet according to claim 1, characterized in that its tensile modulus is 850 MPa or more and 1600 MPa or less.

3. The decorative sheet according to claim 1 or 2, characterized in that 50% to 100% by mass of the above-mentioned polypropylene resin consists of a highly crystalline homopolypropylene resin having an isotactic pentad fraction (mmmm fraction) of 95% or more.

4. The decorative sheet according to any one of claims 1 to 3, characterized in that the amount of the nano-sized nucleating agent added is 0.01 parts by mass or more and 0.5 parts by mass or less per 100 parts by mass of the polypropylene resin.

5. The above-mentioned nucleating agent is a nucleating agent vesicle in which the nucleating agent is encapsulated within a vesicle having a single-layer outer membrane. The decorative sheet according to any one of claims 1 to 4, characterized in that the above-mentioned nucleating agent vesicles are added in an amount of 0.01 parts by mass or more and 0.5 parts by mass or less, calculated as nucleating agent in the above-mentioned nucleating agent vesicles, per 100 parts by mass of the above-mentioned polypropylene resin.

6. The above-mentioned nucleating agent is a nucleating agent vesicle in which the nucleating agent is encapsulated within a vesicle having a single-layer outer membrane. The cosmetic sheet according to any one of claims 1 to 5, characterized in that the nucleating agent vesicle is a nucleating agent liposome having an outer membrane made of phospholipids.

7. The above-mentioned nucleating agent is a nucleating agent vesicle in which the nucleating agent is encapsulated within a vesicle having a single-layer outer membrane. The decorative sheet according to any one of claims 1 to 6, characterized in that the amount of the nucleating agent vesicle added is 0.01 parts by mass or more and 0.5 parts by mass or less in terms of nucleating agent in the nucleating agent vesicle, per 100 parts by mass of the polypropylene resin.

8. A decorative sheet according to any one of claims 1 to 7, characterized in that a pattern layer is laminated on one side of the above-mentioned base material layer.

9. The decorative sheet according to claim 2, characterized in that the tensile modulus is the tensile modulus of the base material layer.

10. The cosmetic sheet according to any one of claims 1 to 9, characterized in that the nano-sized nucleating agent comprises a metal benzoate salt, a metal pimephosphate salt, a metal rosin salt, benzylidene sorbitol, quinacridone, cyanine blue, or talc.

11. The decorative sheet according to any one of claims 1 to 9, characterized in that the above-mentioned base material layer does not contain aluminosilicate, metal hydroxide, lithium silicate, silica gel, or alumina.

12. The decorative sheet according to any one of claims 1 to 9, characterized in that the non-melting nucleating agent is a metal phosphate salt, a metal benzoate salt, a metal pimephosphate salt, or a metal rosin salt.

13. The decorative sheet according to any one of claims 1 to 12, characterized in that the above-mentioned base material layer does not contain a foaming agent and 1,2-polybutadiene, respectively.

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