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] The present invention relates to a decorative sheet used as a building material for the exterior and interior of buildings, the surface of building fixtures, the surface material of home appliances, etc. [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 decorative sheets made of polyvinyl chloride, which are environmentally hazardous. These decorative sheets do not use vinyl chloride resin, and therefore the generation of toxic gases and the like during incineration is suppressed. However, polypropylene sheets generally have issues such as poor scratch resistance due to their low elastic modulus, and they tend to stretch when tension is applied to the sheets during sheet production for printing, etc.

[0003] A decorative sheet is attached to the surface of a substrate, such as a wood substrate, metal substrate, or non-flammable substrate, to form a decorative board, which then imparts a design to the decorative board according to its intended purpose. Therefore, the decorative sheet must completely conceal the surface of the substrate as needed. In this case, a decorative sheet that is at least colored with a pigment and has concealing properties must be used. The simplest decorative sheet configuration is one consisting of only a base layer made of a single colored sheet (single layer). With such a decorative sheet consisting of only a base layer, the designs that can be imparted are typically limited to a single color without a pattern. However, by adding a lustrous pigment, such as aluminum flake or pearl pigment, a lustrous effect can be imparted, making it possible to achieve a sufficient design. Furthermore, if a more sophisticated design is desired, it is also effective to decorate the surface of the base layer, for example by printing.

[0004] On the other hand, as mentioned above, colored polypropylene films have a low modulus of elasticity, so when used as a single-layer decorative sheet, they need to be scratch-resistant and not stretch even when tension is applied during processing such as printing. The stretchability when tension is applied can be improved in conventional colored polypropylene films by increasing the layer thickness to about 50 μm or more. Furthermore, the scratch resistance of conventional colored polypropylene films can be improved by providing a transparent resin layer made of polypropylene resin or a top coat layer using a urethane-based thermosetting resin made of polyol and isocyanate, as in Patent Documents 2 and 3.

[0005] Furthermore, as in Patent Documents 2 and 3, by optimally selecting the polypropylene resin used in the colored polypropylene film, it is possible to improve scratch resistance and elongation during printing. However, while increasing the crystallinity improves the elastic modulus, the breaking stress does not increase commensurately with the elastic modulus, making the film itself more susceptible to tearing, and problems such as breakage during printing. Furthermore, during post-processing as a decorative sheet, particularly during bending such as V-cutting, problems such as cracking and whitening at the bent portions 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 Summary of the Invention [Problem to be solved by the invention]

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

[0008] The present inventors have discovered that by adding a nucleating agent that improves the crystallinity of polypropylene, for example by encapsulating it in a vesicle having a single-layer outer membrane to form a nucleating agent vesicle, and then by conducting various studies and experiments on the manufacturing process to optimize the crystallinity range, it is possible to provide a decorative sheet and a manufacturing method thereof that alleviates the above-mentioned problems. To achieve the object, a decorative sheet according to one embodiment of the present invention has a substrate layer made of a colored polypropylene film obtained by mixing an inorganic pigment into a polypropylene resin, the substrate layer contains a nano-sized nucleating agent, the thickness of the substrate 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 measurement is 0.7 or more and 0.9 or less. Note that in the decorative sheet according to one embodiment of the present invention, the nucleating agent may be contained in the form of a nucleating agent vesicle in which the nucleating agent is encapsulated in an outer membrane and turned into a vesicle. Here, the nucleating agent vesicle is a capsule-like vesicle having a single-layer outer membrane and encapsulating a nucleating agent, and can be prepared, for example, by supercritical reverse phase evaporation. The nucleating agent is a substance that serves as a starting point for crystallization in a crystalline polypropylene resin. [Effects of the Invention]

[0009] According to one aspect of the present invention, a nucleating agent that improves the crystallinity of polypropylene is, for example, vesiculated and added as a nucleating agent vesicle, and the peak intensity ratio value and film thickness obtained in Fourier infrared spectroscopy measurement are optimized, thereby providing a decorative sheet that can be provided with printability (such as resistance to stretching), scratch resistance, and bending processability. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a decorative sheet according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing another decorative sheet according to an embodiment of the present invention. 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 Figure 1 is an example of a single-layer structure consisting of only a substrate layer 2 (raw fabric layer). The substrate layer 2 of this embodiment is made of a colored polypropylene film. The substrate layer 2 made of a colored polypropylene film contains a polypropylene resin mixed with an inorganic pigment for coloring, and also contains a nano-sized nucleating agent. Note that in this embodiment, the nucleating agent may be contained in the form of, for example, a nucleating agent vesicle, which is formed by being encapsulated in an outer membrane.

[0013] The thickness of the base 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 infrared spectroscopy is 0.7 or more and 0.9 or less. The polypropylene resin constituting the base layer 2 is preferably a highly crystalline homopolypropylene resin having an isotactic pentad fraction (mmmm fraction) of 95% or more, with 50% or more and 100% or less by mass being the polypropylene resin.

[0014] The amount of the nano-sized nucleating agent added is preferably 0.01 parts by mass or more and 0.5 parts by mass or less relative to 100 parts by mass of the polypropylene resin. When a nucleating agent vesicle is used, the amount of the nucleating agent vesicle added is preferably 0.01 to 0.5 parts by mass, calculated as the nucleating agent in the nucleating agent vesicle, per 100 parts by mass of polypropylene resin. The nucleating agent vesicle is preferably a nucleating agent liposome having an outer membrane made of phospholipids.

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

[0016] Depending on the design requirements, at least one of the transparent resin layer 4 and the top coat layer 5 may be provided with an embossed pattern (embossed pattern 4a). Ink can be embedded in the embossed pattern 4a to further enhance the design. If there are problems with the adhesion between the design layer 3 and the transparent resin layer 4, an adhesive resin layer 4b may be provided as appropriate. When the adhesive resin layer 4b is provided, it is formed by co-extrusion of the transparent resin layer 4 and the adhesive resin layer 4b. The adhesive resin layer 4b may be, for example, an acid-modified resin such as polypropylene, polyethylene, or acrylic resin. The thickness of the adhesive resin layer 4b is preferably 2 μm or more to improve adhesive strength. Furthermore, depending on requirements such as scratch resistance, at least one of the transparent resin layer 4 and the top coat layer 5 may be laminated in multiple layers, and other known layers may also be disposed.

[0017] 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 wood boards, inorganic boards, metal plates, and composite boards made of multiple materials. A primer layer 6 or a concealing layer (not shown) may be provided between the decorative sheet 1 and the substrate B as appropriate. The tensile modulus of the decorative sheet 1 of this embodiment, particularly the tensile modulus of the base layer 2 alone, is preferably in the range of 850 MPa to 1600 MPa. If the tensile modulus is less than 850 MPa, problems during printing may not be suppressed. If the tensile modulus exceeds 1600 MPa, the crystallinity is too high, and problems such as whitening and cracking may occur during bending, even when a nucleating agent (for example, nucleating agent vesicles) is used.

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

[0019] (polypropylene resin) The polypropylene resin is preferably a highly crystalline homopolypropylene, which will be described later, but is not limited to the highly crystalline homopolypropylene. In applications where processability, such as bending, is more important, 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 infrared spectroscopy of the base layer 2 made of a colored polypropylene film is adjusted to 0.7 or more and 0.9 or less. If the peak intensity ratio x is less than 0.7, defects during printing processing cannot be suppressed, and it is likely that 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 defects such as whitening and cracking may occur during bending processing, even when nucleating agent vesicles are used.

[0021] Here, we will explain Fourier 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, utilizing the principle that the amount of infrared light, which is light with a wavelength of 2.5 μm to 25 μm, absorbed by the substance changes 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 split transmitted light and reflected light, and calculating the light intensity of each wavenumber component from the signal intensity of the interference wave to measure the infrared spectrum. In particular, in this embodiment, the interference wave is calculated using the Fourier transform method, and measurement is performed by Fourier infrared spectroscopy, a method for measuring infrared spectra. A graph in which the wavenumber obtained by the above method is plotted 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 is observed for each substance. In this case, the absorbance on the vertical axis changes in peak intensity 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 parts, so 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 obtain the absorbance at the wavenumber 997 cm , which corresponds to the absorbance of the crystalline portion of the colored polypropylene film in the absorption spectrum obtained by the above-described measurement. -1 and the wavenumber 973 cm corresponding to the absorbance of the amorphous part of the film. -1 The ratio of the peak intensity of the colored polypropylene film to the peak intensity of the colored polypropylene film, i.e., the peak intensity ratio x, which represents the crystallinity of the polypropylene, is calculated using the following formula, and the relationship between the peak intensity ratio x and the rigidity of the colored polypropylene film is clarified. The present invention provides a decorative sheet having excellent rigidity, which employs a colored polypropylene film having a peak intensity ratio x within a predetermined range as a base layer. -1 Peak intensity and wavenumber 973cm -1 The peak intensities are at wavenumber 938 cm -1 The background correction was performed using the peak intensity of

[0023]

number

[0024] It is also important that the thickness of the base layer 2 made of a colored polypropylene film is 50 μm or more and 150 μm or less. If the thickness of the base layer 2 is less than 50 μm, the film strength will be insufficient even if the peak intensity ratio x is within the optimum range, making it difficult to prevent defects during printing processing and deterioration of scratch resistance. On the other hand, if the thickness of the base layer 2 exceeds 150 μm, problems such as whitening and cracking may occur during bending. In this embodiment, it is preferable to use a polypropylene resin having high crystallinity as the polypropylene resin. 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.

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

[0026] 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.

[0027] (inorganic pigments) As the inorganic pigment, known inorganic pigments, such as titanium oxide, can be used to impart hiding power. Examples of inorganic pigments for coloring include iron-zinc, chromium-antimony, and iron-aluminum composite oxides, as well as iron oxide, and the like, and these can be freely blended to suit the desired color. Furthermore, lustrous materials such as aluminum flakes and pearl pigments can also be added as inorganic pigments. Organic pigments, such as carbon black, can also be used in combination. Furthermore, additives such as fatty acid metal salts may be added to improve dispersibility and extrudability.

[0028] (Nucleating agent vesicles) The base layer 2 also 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, encapsulated in a vesicle having a single-layer outer membrane. Since the base layer 2 contains a nucleating agent, the 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. It is preferable that the average particle size of the nano-sized nucleating agent is less than half the wavelength range of visible light. Specifically, since the wavelength range of visible light is 400 nm or more and 750 nm or less, it is preferable that the average particle size is 375 nm or less.

[0029] Nano-sized nucleating agents have extremely small particle sizes, so the amount of nucleating agent present per unit volume is The number and surface area of ​​nucleating agent particles increase inversely proportional to the cube of the particle diameter. As a result, the distance between each nucleating agent particle becomes shorter. When crystal growth occurs from the surface of one nucleating agent particle added to the polypropylene resin, the end of the growing crystal immediately comes into contact with the end of a crystal growing from the surface of another nucleating agent particle adjacent to the first nucleating agent particle. The ends of the crystals hinder each other's growth, stopping the growth of each crystal. This allows the average particle size of the spherulites in the crystalline portion of the crystalline polypropylene resin to be reduced, for example, the spherulite size to 1 μm or less. As a result, a colored polypropylene film with high crystallinity and high hardness can be obtained. Furthermore, the stress concentration between spherulites that occurs during bending is efficiently dispersed, allowing a colored polypropylene film that is less susceptible to cracking and whitening during bending to be realized.

[0030] Here, 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 smaller than when added as nucleating agent vesicles. As a result, the average particle size of the spherulites in the crystalline portion of the polypropylene resin increases, and cracking and whitening during bending tend to be more difficult to suppress compared to when 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 and processability by increasing the crystallinity compared to when added as nucleating agent vesicles.

[0031] The base layer 2 made of a colored polypropylene film constituting the decorative sheet 1 of this embodiment preferably contains 0.01 to 0.5 parts by mass, preferably 0.05 to 0.3 parts by mass, of nucleating agent (nucleating agent vesicle) per 100 parts by mass of polypropylene resin as the main component. If the amount of nucleating agent (nucleating agent vesicle) added is less than 0.01 parts by mass, the crystallinity may not be sufficiently improved, and the required modulus of elasticity (hardness) may not be achieved. Furthermore, if the amount added exceeds 0.5 parts by mass, the crystalline nuclei may be excessive, inhibiting spherulite growth, resulting in an insufficient improvement in crystallinity and a risk of not achieving the required modulus of elasticity (hardness).

[0032] Furthermore, methods for nano-sizing nucleating agents include, for example, solid-phase methods, which primarily involve mechanical pulverization of the nucleating agent to obtain nano-sized particles; liquid-phase methods, which involve the synthesis and crystallization of nano-sized particles in a solution containing the nucleating agent; and gas-phase methods, which involve the synthesis and crystallization of nano-sized particles from a gas or vapor containing the nucleating agent. Examples of solid-phase methods include ball mills, bead mills, rod mills, colloid mills, conical mills, disk mills, hammer mills, and jet mills. Examples of liquid-phase methods include crystallization, coprecipitation, sol-gel processes, liquid-phase reduction, and hydrothermal synthesis. Examples of gas-phase methods include, for example, electric furnace processes, chemical flame processes, laser processes, and thermal plasma processes.

[0033] Supercritical reverse-phase evaporation is a preferred method for nano-sizing nucleating agents. Supercritical reverse-phase evaporation is a method for producing capsules (nano-sized vesicles) encapsulating a 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 at or above the critical temperature (30.98°C) and critical pressure (7.3773±0.0030 MPa). Carbon dioxide under temperature or pressure conditions above the critical point refers to carbon dioxide under conditions where only the temperature or pressure exceeds the critical conditions.

[0034] In addition, a specific nano-processing method using supercritical reverse-phase evaporation involves first injecting an aqueous phase into a fluid mixture of supercritical carbon dioxide, phospholipids as an outer membrane-forming substance, and a nucleating agent as an encapsulating substance, and then stirring to generate an emulsion of supercritical carbon dioxide and aqueous phase. Next, by reducing the pressure, the carbon dioxide expands and evaporates, causing a phase inversion, producing nanocapsules (nanovesicles) in which the phospholipids cover the surface of the nucleating agent particles with a single-layer membrane. Unlike conventional encapsulation methods, in which the outer membrane on the surface of the nucleating agent particles becomes multi-layered, this supercritical reverse-phase evaporation method makes it easy to produce capsules with a single membrane, allowing for the preparation of smaller capsules. Nucleating agent vesicles can be prepared by, for example, the Bangham method, extrusion method, hydration method, surfactant dialysis method, reverse phase evaporation method, freeze-thaw method, supercritical reverse phase evaporation method, etc. Among these, supercritical reverse phase evaporation method is particularly preferred. The outer membrane constituting the nucleating agent vesicle is composed of, for example, a monolayer membrane, and the outer membrane is composed of a substance containing, for example, a biological lipid such as a phospholipid.

[0035] Nucleating vesicles whose outer membrane is composed of materials containing biological lipids such as phospholipids are referred to herein as nucleating liposomes. Examples of phospholipids constituting the outer membrane include glycerophospholipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, cardiopin, egg yolk lecithin, hydrogenated egg yolk lecithin, soybean lecithin, and hydrogenated soybean lecithin, and sphingophospholipids such as sphingomyelin, ceramide phosphorylethanolamine, and ceramide phosphorylglycerol.

[0036] Other substances that form the outer membrane of the vesicles include dispersants such as nonionic surfactants and mixtures of these with cholesterols or triacylglycerols. Among these, nonionic surfactants can be used alone or in combination with one or more of the following: polyglycerol 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, polyoxyethylene-polycaprolactam copolymer, etc. Cholesterols that can be used include, for example, cholesterol, α-cholestanol, β-cholestanol, cholestane, desmosterol (5,24-cholestadien-3β-ol), sodium cholate, and cholecalciferol.

[0037] The outer membrane of the liposome may also be formed from a mixture of phospholipids and a dispersant. In the decorative sheet 1 of this embodiment, it is preferable that the nucleating agent vesicle is a radical scavenger liposome equipped with an outer membrane made of phospholipids, and by forming the outer membrane from phospholipids, it is possible to improve the compatibility between the resin material, which is the main component of the base layer 2, and the vesicle.

[0038] The nucleating agent is not particularly limited as long as it is a substance that serves as a starting point for crystallization when the resin crystallizes. Examples of nucleating agents include metal phosphate salts, metal benzoates, metal pimelate 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 benzoates, metal pimelate salts, and metal rosin salts, which are non-melting and expected to have good transparency. However, if the material itself can be made transparent by the nano-processing, colored quinacridone, cyanine blue, talc, etc. can also be used. Furthermore, a non-melting nucleating agent may be appropriately mixed with melting benzylidene sorbitol.

[0039] As mentioned above, one of the features (invention-specific matters) 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 encapsulated in vesicles to the resin composition, the dispersibility of the nucleating agent in the resin material, i.e., in the base layer 2, is dramatically improved. Direct identification based on the structure or properties of an object in the state of sheet 1 may be difficult depending on the situation, and is therefore impractical. The reason for this is as follows: A nucleating agent added in the form of vesicles is dispersed with high dispersibility, and even in the state of the produced decorative sheet 1, the nucleating agent is highly dispersed in the base layer 2. However, in the process of producing decorative sheet 1 after adding the nucleating agent in the form of vesicles to the resin composition that makes up the base layer 2 to produce the base layer 2, various treatments such as compression treatment and hardening treatment are usually performed on the laminate. However, these treatments may cause the outer membrane of the vesicles encapsulating the nucleating agent to be crushed or chemically reacted, and there is a high possibility that the nucleating agent is not enclosed (enveloped) by the outer membrane, and the state in which the outer membrane is crushed or chemically reacted varies depending on the treatment process of the decorative sheet 1. In situations where the nucleating agent is not encapsulated in an outer membrane, it is difficult to specify the physical properties within a numerical range, and it is also possible that it may be difficult to determine whether the material constituting the shattered outer membrane is the outer membrane of the vesicles or a material added separately from the nucleating agent. Thus, although the present invention differs from the prior art in that the nucleating agent is blended in a highly dispersed state in the base layer 2, it is also possible that there may be cases where it is impractical to specify within a numerical range a value obtained by analyzing the structure and properties of the decorative sheet 1 based on measurements to determine whether the nucleating agent was added in the form of vesicles encapsulating the nucleating agent. Here, the nucleating agent vesicles having the above-mentioned structure may also be contained in the transparent resin layer 4 and the top coat layer 5.

[0040] (Picture layer 3) A pattern layer 3 can be provided on the surface of the colored polypropylene film (base layer 2) to impart 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-trimmed patterns, and geometric shapes. Furthermore, a base solid ink layer (not shown) may be provided between the base layer 2 and the picture layer 3 depending on the level of the desired design. The base solid ink layer is provided so as to cover the entire surface of the base layer 2. The base solid ink layer may also be multi-layered, with two or more layers, as needed for hiding properties, etc. Furthermore, the picture layer 3 may be formed by laminating the same number of plates as necessary to express the desired design. In this way, the picture layer 3 and the base solid ink layer can be combined in various ways depending on the desired design, i.e., the design to be expressed, but there are no particular limitations.

[0041] The materials constituting the base solid ink layer and the design layer 3 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 resins, two-component urethane resins, acrylic resins, styrene resins, polyester resins, urethane resins, polyvinyl resins, alkyd resins, epoxy resins, melamine resins, fluorine-containing resins, silicone resins, and rubber resins, 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, iron blue, 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.

[0042] In addition, 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 to impart various functions. Here, the base solid ink layer and the pattern layer 3 are formed by, for example, gravure printing or offset printing. The base solid ink layer can be formed by various printing methods such as a printing method, a screen printing method, an electrostatic printing method, an inkjet printing method, etc. In addition, since the base solid ink layer covers the entire surface of the base material layer 2, it can also be formed by various coating methods such as a roll coating method, a knife coating method, a microgravure coating method, a die coating method, etc. These printing methods and coating methods may be selected separately depending on the layer to be formed, but it is more efficient to select the same method and process all the layers at once.

[0043] (Transparent resin layer 4) The resin material used as the main component of the transparent resin layer 4 is preferably made 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 such copolymers include homopolymers or copolymers of two or more types of α-olefins (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.) and copolymers of ethylene or α-olefins with other monomers, such as ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, etc. Furthermore, when it is intended to improve the surface strength of the decorative sheet 1, it is preferable to use a highly crystalline polypropylene resin, as with the base layer 2. Here, in this specification, the term "main component" refers to 90% by mass or more 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 may be low, which may diminish the significance of providing the transparent resin layer 4. If it exceeds 100 μm, the decorative sheet 1 may have too high rigidity, which may cause problems such as whitening and cracking during bending. However, when the top coat layer 5 is provided on the transparent resin layer 4, the thickness of the transparent resin layer 4 may be less than 50 μm. The resin composition constituting the transparent resin layer 4 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.

[0045] (Top coat layer 5) If further improvement in scratch resistance or adjustment of gloss is required, a top coat layer 5 can be provided on the surface of the transparent resin layer 4. The resin material that is the main component of the top coat layer 5 can be appropriately selected from polyurethane-based, acrylic silicone-based, fluorine-based, epoxy-based, vinyl-based, polyester-based, melamine-based, aminoalkyd-based, and urea-based resin materials. The form of the resin material is not particularly limited, and can 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.

[0046] The resin material used as the main component of the top coat layer 5 is a water-based resin containing isocyanate. Isocyanates based on ethylenediisocyanate are preferred from the standpoints of workability, cost, and the cohesive strength of the resin itself. 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. However, considering weather resistance, curing agents based on hexamethylene diisocyanate (HMDI) or isophorone diisocyanate (IPDI), which have a linear molecular structure, are preferred. Additionally, to improve surface hardness, it is preferable to use resins that are cured with active energy rays such as ultraviolet light or electron beams. These resins can be used in combination with one another. For example, by using a hybrid type of thermosetting resin and photocuring resin, it is possible to improve surface hardness, suppress shrinkage on curing, and improve adhesion.

[0047] A gloss adjuster can be added to the top coat layer 5 to adjust the gloss. Commercially available gloss adjusters can be used. For example, fine particles made of inorganic materials such as silica, glass, alumina, calcium carbonate, and barium sulfate can be used. 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, acrylic, and the like. In particular, among fine particles such as silica and glass, gloss adjusters with low bulk density, which are not solid spherical particles but are formed by secondary aggregation of fine primary 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.

[0048] In addition, functional additives such as antibacterial agents and antifungal agents may be added to impart various functions to the top coat layer 5. 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. The thickness of the top coat layer 5 is preferably 3 μm or more and 15 μm or less. If it is less than 3 μm, the effect of improving scratch resistance may be low, which may diminish the significance of providing the top coat layer 5. If it is more than 15 μm, cracks or breakage may occur during bending, which may cause problems with the design or deteriorate the weather resistance.

[0049] <Manufacturing method> A manufacturing example of the decorative sheet 1 will now be described. A nucleating agent vesicle is prepared by encapsulating a nucleating agent in a vesicle to form the nucleating agent, and the prepared nucleating agent vesicle is added to a polypropylene resin together with an inorganic pigment to prepare a resin material for the base layer. The nucleating agent vesicle is prepared, for example, by encapsulating the nucleating agent in a vesicle having a monolayer membrane by supercritical reverse phase evaporation to form a vesicle. The polypropylene resin used preferably contains 50% by mass or more and 100% by mass or less of a highly crystalline homopolypropylene resin having an isotactic pentad fraction (mmmm fraction) of 95% or more.

[0050] The resin material for the base layer is heated and melted, and formed into a sheet having 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 by Fourier infrared spectroscopy measurement of the base layer 2 is controlled to be 0.7 or more and 0.9 or less. Furthermore, if necessary, a pattern layer 3 is formed on the upper surface of the base layer 2 by printing, and a transparent At least one of the resin layer 4 and the top coat layer 5 is formed by printing. In the above-described manufacturing method, the base layer 2 is manufactured using nucleating agent vesicles, but the present invention is not limited to this. For example, the base layer 2 may be manufactured by replacing the nucleating agent vesicles with a nano-sized nucleating agent that is not encapsulated in a vesicle.

[0051] <Other effects> (1) The decorative sheet 1 of this embodiment has a substrate layer 2 made of a colored polypropylene film obtained by mixing an inorganic pigment with a polypropylene resin, the substrate layer 2 contains a nano-sized nucleating agent, the thickness of the substrate 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 substrate 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 measurement, and the film thickness, it is possible to provide a decorative sheet 1 that is compatible with printability (resistance to stretching, etc.), scratch resistance, and bending processability.

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

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

[0054] (4) In the decorative sheet 1 of this embodiment, the nucleating agent 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 vesiculated and added as a nucleating agent vesicle, and by further optimizing the value of the peak intensity ratio x calculated from the absorption spectrum obtained by Fourier infrared spectroscopy measurement and the film thickness, it is possible to provide a decorative sheet 1 that is compatible with printability (resistance to stretching, etc.), scratch resistance, and bending processability.

[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 so that the amount of nucleating agent in the nucleating agent vesicles is within the range of 0.05 parts by mass or more and 0.5 parts by mass or less. According to this configuration, a nucleating agent that improves the crystallinity of polypropylene is vesiculated and added as a nucleating agent vesicle, and by further optimizing the value of the peak intensity ratio x calculated from the absorption spectrum obtained by Fourier infrared spectroscopy measurement and the film thickness, it is possible to provide a decorative sheet 1 that is compatible with printability (resistance to stretching, etc.), scratch resistance, and bending processability.

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

[0057] (7) In the decorative sheet 1 of this embodiment, the nucleating agent vesicles are preferably nucleating agent liposomes having an outer membrane made of phospholipids. This configuration allows for good compatibility between the resin material that is the main component of the base layer 2 and the vesicles. (8) In the decorative sheet 1 of this embodiment, it is preferable that a pattern layer 3 be laminated on one surface of the base layer 2 . According to this configuration, the design of the decorative sheet 1 can be improved. (9) In the decorative sheet 1 of this embodiment, it is preferable that at least one of the transparent resin layer 4 and the top coat layer 5 is laminated on one surface of the base layer 2 .

[0058] [Example] Specific examples of the decorative sheet 1 of this embodiment will be described below. (Method for producing nucleating agent vesicles) First, the method for producing the nucleating agent liposome used in this example will be described. Nucleating agent liposomes were prepared using the supercritical reverse phase evaporation method described above. 100 parts by weight of methanol, 70 parts by weight of a phosphate ester metal salt nucleating agent (ADK STAB NA-21; manufactured by ADEKA Corporation) as the nucleating agent, and 5 parts by weight of phosphatidylcholine as the phospholipid that constitutes the outer membrane of the vesicles were placed in a high-pressure stainless steel vessel maintained at 60°C and sealed. Carbon dioxide was then injected into the vessel to create a supercritical state at a pressure of 20 MPa. The vessel was then vigorously stirred, and 100 parts by weight of ion-exchanged water was then injected. After stirring and mixing for an additional 15 minutes while maintaining the temperature and pressure in the supercritical state, the carbon dioxide was evacuated from the vessel and the pressure was returned to atmospheric pressure, yielding nucleating agent vesicles encapsulating the nucleating agent in vesicles with a monolayer outer membrane composed of phospholipids.

[0059] Example 1 As the raw material for the colored polypropylene film, 78 parts by mass of highly crystalline homopolypropylene resin having 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 added to 6 parts by mass of titanium oxide pigment as an inorganic pigment, 16 parts by mass of chromium-antimony composite oxide pigment as a nucleating agent, and 0.01 part by mass of the above-mentioned nucleating agent vesicle as a nucleating agent, and the mixture was extruded using a melt extruder to form a substrate layer 2 consisting of a colored polypropylene film with a thickness of 55 μm. Example 2 A substrate layer 2 having a thickness of 55 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 1, except that the above-mentioned nucleating agent vesicle was added as a nucleating agent in an amount of 0.5 parts by mass.

[0060] Example 3 The raw materials for the colored polypropylene film were 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 by mass of a random polypropylene resin containing 4% ethylene and having a melt flow rate (MFR) of 12 g / 10 min (230°C), 6 parts by mass of titanium oxide pigment as inorganic pigments, 16 parts by mass of chromium-antimony composite oxide pigment, and 0.01 part by mass of the above-mentioned nucleating agent vesicle as a nucleating agent, and extrusion molding was carried out using a melt extruder to produce a base layer 2 made of a 55 μm thick colored polypropylene film.

[0061] Example 4 In the examples, the nucleating agent vesicles were added in an amount of 0.5 parts by mass as a nucleating agent. As in 3, a base layer 2 having a thickness of 55 μm was formed by extrusion molding using a melt extruder. Example 5 As in Example 1, a base layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder. Example 6 As in Example 2, a base layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder. Example 7 As in Example 3, a base layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder. Example 8 As in Example 4, a base layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder.

[0062] Example 9 A design layer 3 was formed by printing a design on the surface of a 55 μm-thick substrate layer 2 prepared in the same manner as in Example 1. The design layer 3 was formed using a two-component urethane ink (V180; manufactured by Toyo Ink Co., Ltd.) to which 0.5 parts by mass of a hindered amine light stabilizer (Chimasorb 944; manufactured by BASF) had been added relative to the binder resin content of the ink. A primer layer 6 was also 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 used for the design layer 3. Next, 100 parts by mass of crystalline polypropylene resin (pentad fraction 97.8%, molecular weight distribution 2.3, MFR 18g / 10min) was mixed with 0.5 parts by mass of a hindered amine light stabilizer (BASF's "Chimasorb 944") and 0.5 parts by mass of a benzotriazole UV absorber (BASF's "Tinuvin 328") and a polyethylene-based easy-adhesion resin. The mixture was co-extruded using a melt extruder to form a 60 μm thick transparent resin layer 4 and a 10 μm thick adhesive resin layer 4b. Next, a dry lamination adhesive (Takelac A540; Mitsui Chemicals, Inc.; coating amount 2 g / m) was applied to the surface of the substrate on which the pattern layer 3 was formed. 2 ) was applied to the substrate. Subsequently, the pattern layer 3 of the substrate coated with the adhesive and the transparent resin layer 4 were bonded together by extrusion lamination via the formed adhesive resin layer 4b. Furthermore, the surface of the laminated sheet facing the transparent resin layer 4 was pressed using an embossing die roll to form an embossed pattern 4a, and then a two-component curing urethane top coat ("W184" manufactured by DIC Graphics Corporation) was applied in an amount of 3 g / m2 onto the surface with the embossed pattern 4a. 2 to form a top coat layer 5. In this way, the decorative sheet 1 shown in FIG. 2 was obtained.

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

[0064] Example 13 A transparent resin layer 4 and a top coat layer 5 were formed in the same manner as in Example 9 on a substrate layer 2 having a thickness of 145 μm, which was prepared in the same manner as in Example 5, to obtain a decorative sheet 1. Example 14 The substrate layer 2 having a thickness of 145 μm was prepared in the same manner as in Example 6. A resin layer 4 and a top coat layer 5 were formed, and a decorative sheet 1 was obtained. Example 15 A transparent resin layer 4 and a top coat layer 5 were formed in the same manner as in Example 9 on a substrate layer 2 having a thickness of 145 μm, which was prepared in the same manner as in Example 7, to obtain a decorative sheet 1. Example 16 A transparent resin layer 4 and a top coat layer 5 were formed in the same manner as in Example 9 on a substrate layer 2 having a thickness of 145 μm, which was prepared in the same manner as in Example 8, to obtain a decorative sheet 1.

[0065] Example 17 A substrate layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 7, except that a nucleating agent without an outer membrane was used instead of the above-mentioned nucleating agent vesicle. Example 18 A substrate layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 8, except that a nucleating agent without an outer membrane was used instead of the above-mentioned nucleating agent vesicle. Example 19 A substrate layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 5, except that a nucleating agent without an outer membrane was used instead of the above-mentioned nucleating agent vesicle. Example 20 A substrate layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 6, except that a nucleating agent without an outer membrane was used instead of the above-mentioned nucleating agent vesicle.

[0066] (Comparative Example 1) A substrate layer 2 having a thickness of 55 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 1, except that an untreated nucleating agent was used instead of the above-mentioned nucleating agent vesicles. (Comparative Example 2) A substrate layer 2 having a thickness of 55 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 2, except that an untreated nucleating agent was used instead of the above-mentioned nucleating agent vesicles. (Comparative Example 3) A substrate layer 2 having a thickness of 55 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 3, except that an untreated nucleating agent was used instead of the above-mentioned nucleating agent vesicles. Comparative Example 4 A substrate layer 2 having a thickness of 55 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 4, except that an untreated nucleating agent was used instead of the above-mentioned nucleating agent vesicles.

[0067] (Comparative Example 5) A substrate layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 5, except that an untreated nucleating agent was used instead of the above-mentioned nucleating agent vesicles. (Comparative Example 6) A substrate layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 6, except that an untreated nucleating agent was used instead of the above-mentioned nucleating agent vesicles. (Comparative Example 7) A substrate layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 7, except that an untreated nucleating agent was used instead of the above-mentioned nucleating agent vesicles. (Comparative Example 8) A substrate layer 2 having a thickness of 145 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 8, except that an untreated nucleating agent was used instead of the above-mentioned nucleating agent vesicles.

[0068] (Comparative Example 9) As in Comparative Example 2, a base layer 2 having a thickness of 155 μm was formed by extrusion molding using a melt extruder. Thereafter, as in Example 9, a transparent resin layer 4 and a top coat layer 5 were formed, and a decorative sheet was obtained. I got the top 1. (Comparative Example 10) A substrate layer 2 having a thickness of 155 μm was formed by extrusion molding using a melt extruder in the same manner as in Example 2. Thereafter, 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 1 was obtained. (Comparative Example 11) As in Example 2, a base layer 2 having a thickness of 45 μm was formed by extrusion molding using a melt extruder.

[0069] (Comparative Example 12) The raw materials for the colored polypropylene film were 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, 46.8 parts of random polypropylene resin containing 4% ethylene and having a melt flow rate (MFR) of 12 g / 10 min (230°C), 6 parts by mass of titanium oxide pigment as inorganic pigments, 16 parts by mass of chromium-antimony composite oxide pigment, and 0.5 parts by mass of the above-mentioned nucleating agent vesicle as a nucleating agent, and extrusion molding was carried out using a melt extruder to produce a base layer 2 made of a 55 μm thick colored polypropylene film.

[0070] (Comparative Example 13) The raw materials for the colored polypropylene film were 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 by mass of a random polypropylene resin containing 4% ethylene and having a melt flow rate (MFR) of 12 g / 10 min (230°C), 6 parts by mass of titanium oxide pigment as inorganic pigments, 16 parts by mass of chromium-antimony composite oxide pigment, and 1.0 part by mass of the above-mentioned nucleating agent vesicle as a nucleating agent, and extrusion molding was carried out using a melt extruder to produce a base layer 2 made of a 55 μm thick colored polypropylene film.

[0071] (evaluation) For the above Examples 1 to 20 and Comparative Examples 1 to 13, Fourier infrared spectroscopy, measurement of tensile modulus, defects during printing (suitability for printing), scratch resistance, suitability for bending, and lapping smoothness (surface uniformity during lapping) were evaluated. <Fourier-type infrared spectroscopy> Fourier-type infrared spectroscopy was performed using a PerkinElmer Fourier-type infrared spectrometer (Spectrum Spotlight 400) at 4000 cm -1 From 700cm -1 The absorption spectrum was obtained from the obtained absorption spectrum. -1 , 973cm -1 , 938cm -1 The peak intensity ratio was extracted and the peak intensity ratio x was calculated using the following formula.

[0072]

number

[0073] <Tensile modulus> The tensile modulus was measured using an autograph (AGS-500NX) manufactured by Shimadzu Corporation, and a tensile test was carried out at a tensile speed of 50 mm / min, and the tensile modulus was calculated. <Problems during printing (printing suitability)> The design layer 3 was formed by gravure printing using a gravure printing machine, and the substrate layer 2 was stretched by tension during the printing, resulting in misregistration during lamination of each color, which was evaluated as a printing defect. If no register adjustment was required at all, it was marked "◎", if it could be easily adjusted by automatic register adjustment, it was marked "○", if care was required for register adjustment, it was marked "△", and if register adjustment was impossible and printing could not continue, it was marked "X". Also, if the film broke frequently during printing and there were problems with mass production, it was marked "X". Note that a rating of "△" or higher means there are no problems with the printing process.

[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 pencil was fixed at an angle of 45±1° relative to the decorative sheet 10, and the pencil was slid with a load of 750 kg applied to it, and the surface condition of the decorative sheet 10 was observed (in accordance with the old JIS standard JISK5400). The test was conducted five times, and pencil scratches and marks were evaluated. The case where no scratches or marks were visible was rated as "◎", the case where slight pencil marks were visible was rated as "◯", the case where pencil marks were visible was rated as "△", and the case where pencil scratches or tears in the colored polypropylene film were visible was rated as "×". If the rating is "○" or higher, there is no practical problem. If the rating is "△" or higher, there is no problem, although the application is limited to furniture and high, vertical surfaces that people cannot touch. A rating of "○" or higher is preferable.

[0075] <Bending process suitability> In the bending process suitability test, the decorative sheet 1 of each of Examples 1 to 20 and Comparative Examples 1 to 13 obtained by the above method was attached to one side of a medium density fiberboard (MDF) as the base layer 2 using a urethane adhesive, and a V-shaped groove was made on the other side of the base layer 2 up to the boundary where the base layer 2 and decorative sheet 1 were attached so as not to scratch the decorative sheet 1 on the opposite side. Next, the base layer 2 was bent to 90 degrees along the V-shaped groove so that the surface of the decorative sheet 1 formed a mountain fold, and the bent portion of the surface of the decorative sheet 1 was observed using an optical microscope to see if there was any whitening or cracking, and the state of bending processability was evaluated. 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 a rating of "△" or higher is acceptable for practical use.

[0076] <Surface uniformity during lapping> In the surface uniformity test during lapping, a square timber consisting of two sheets of medium-density fiberboard (MDF) and three to five sheets of board or particle board glued between them was used as the base layer 2, and the decorative sheet 1 of each of Examples 1 to 20 and Comparative Examples 1 to 13 obtained by the above method was attached by lapping using a hot melt adhesive to obtain a decorative board. Next, the surface where the decorative sheet 1 was glued to the edge of the board was observed, and visual inspection was performed to determine whether there were any surface irregularities caused by irregularities in the board or steps at the bonded parts of the board. Furthermore, the obtained decorative board was left in an environment of 80°C temperature and 85% humidity for 1000 hours, and the surface irregularities and peeling of the decorative sheet 1 at the same location were checked. A smooth surface with no visible irregularities or steps was rated as "◎" initially or after 1000 hours, a slightly rough surface was rated as "○", a partial surface irregularity or step was rated as "△", and an overall surface irregularity or step was rated as "×" or "×". Note that a rating of "△" or higher is acceptable for practical use, but a rating of "○" or higher is preferred. The evaluation results are shown in Table 1.

[0077] [Table 1]

[0078] As can be seen from Table 1, in the decorative sheets 1 of Examples 1 to 8 and 17 to 20, It can be seen that the decorative sheets 1 of Examples 9 to 16 are obtained by laminating a pattern layer 3, a transparent resin layer 4, and a top coat layer 5 to Examples 1 to 9, and are able to achieve both high design quality and high scratch resistance while also being able to be bent.

[0079] On the other hand, in the decorative sheets 1 of Comparative Examples 1 to 9, a micro-sized nucleating agent that was not vesiculated was used, and therefore the improvement in strength due to the improvement in crystallinity was insufficient, and problems occurred during printing, particularly when the film thickness was thin and the blending ratio of highly crystalline homopolypropylene resin was low. Furthermore, even when there were no problems during printing, some of the decorative sheets 1 lacked the strength required, or problems occurred during bending. These are thought to be due to the lower ability to improve crystallinity compared to vesiculated nucleating agents, and the relatively larger spherulite size.

[0080] Furthermore, in the decorative sheets 1 of Comparative Examples 10 to 13, at least one of the film thickness and peak intensity x of the base layer 2 exceeded the numerical range of the present application, and it was found that the evaluation results showed that one of these was problematic. In Comparative Example 11, although automatic register 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 thickness was too thin, so the film could not withstand tension fluctuations during printing, resulting in an increased frequency of breakage.

[0081] From the above, it was revealed that the decorative sheets 1 of Examples 1 to 20 were decorative sheets 1 that achieved all of the following: defects during printing (printing suitability), scratch resistance, and bending suitability. Furthermore, it was also revealed that the decorative sheets 1 of Examples 1 to 20 also had wrapping process smoothness. 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. [Explanation of symbols]

[0082] 1...decorative sheet, 2...base material 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. a substrate layer made of a colored polypropylene film obtained by mixing an inorganic pigment with a polypropylene resin, the substrate layer containing a nano-sized nucleating agent, the substrate layer having a thickness of 50 μm or more and 150 μm or less, and a value of a peak intensity ratio x calculated from an absorption spectrum obtained by Fourier infrared spectroscopy using the following formula 1 being 0.7 or more and 0.9 or less; the substrate layer further contains a fatty acid metal salt as an additive, The inorganic pigment contains titanium oxide and iron oxide, or contains only titanium oxide, The nucleating agent includes a non-melting type nucleating agent and a melting type nucleating agent, A decorative sheet characterized in that the melt-type nucleating agent is benzylidene sorbitol. Here, in the following formula, I ９９７ The wave number is 997 cm －１ The peak intensity value of I ９３８ The wave number is 938 cm －１ The peak intensity value of I ９７３ The wave number is 973 cm －１ The peak intensity values ​​are shown. [Equation 1]

2. 2. The decorative sheet according to claim 1, wherein the tensile modulus is 850 MPa or more and 1600 MPa or less.

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

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

6. The nucleating agent is a nucleating agent vesicle in which a nucleating agent is encapsulated in a vesicle having a single-layer outer membrane, 6. The decorative sheet according to claim 1, wherein the nucleating agent vesicle is a nucleating agent liposome having an outer membrane made of phospholipids.

7. The nucleating agent is a nucleating agent vesicle in which a nucleating agent is encapsulated in a vesicle having a single-layer outer membrane, A 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, calculated as the nucleating agent in the nucleating agent vesicle, per 100 parts by mass of the polypropylene resin.

8. 8. The decorative sheet according to claim 1, wherein a pattern layer is laminated on one surface of the substrate layer.

9. 3. The decorative sheet according to claim 2, wherein the tensile modulus of elasticity is that of the base material layer.

10. 10. The decorative sheet according to claim 1, wherein the nano-sized nucleating agent comprises a metal salt of benzoic acid, a metal salt of pimelic acid, a metal salt of rosin, benzylidene sorbitol, quinacridone, cyanine blue, or talc.

11. 10. The decorative sheet according to claim 1, wherein the substrate layer does not contain aluminosilicate, metal hydroxide, lithium silicate, silica gel, or alumina.

12. 10. The decorative sheet according to claim 1, wherein the non-melting nucleating agent is a metal salt of phosphate, a metal salt of benzoate, a metal salt of pimelate, or a metal salt of rosin.

13. 13. The decorative sheet according to any one of claims 1 to 12, wherein the substrate layer does not contain a foaming agent and does not contain 1,2-polybutadiene.

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