decorative sheet

Abstract

To provide a decorative sheet excellent in stain resistance and designability.SOLUTION: A decorative sheet 10 includes at least a top coat layer 4 on a substrate layer 1. In the decorative sheet, arithmetic average roughness (Ra0.008) is 10 μm or less in accordance with JIS B0601:2001, measured vertically to a deposition direction when a cut-off value λc is 2.5 mm, a cut-off value λs is 8 μm and an evaluation length is 10 mm, with regard to a front side of the top coat layer 4, and an average length RSm and a ten point average roughness RzJIS of a roughness curve element satisfy a condition of the following equation (1): 5≤RSm / RzJIS≤40 ...(1).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This invention relates to a decorative sheet. [Background technology]

[0002] Decorative sheets are used, for example, as interior and exterior materials for buildings such as houses, as well as building materials such as joinery, fixtures, furniture, fixtures, housing equipment, and home appliances. Some decorative sheets are used for semi-exterior applications such as exterior materials for eaves and entrance doors that are somewhat exposed to wind and rain, and for applications in children's rooms, kitchens / dining rooms, and bathrooms where wipeability against markers and household contaminants, water repellency, and stain resistance are required.

[0003] The decorative materials used in the various applications described above (including decorative panels, decorative paper, decorative sheets, etc.) are required to have durability and weather resistance that can withstand use over long periods of time, such as decades. In addition, they may be required to have stain resistance so that contaminants do not adhere firmly to the surface, so that even if contaminants adhere to the surface due to natural forces such as rainwater or dust, or due to the user's negligence, they can be easily wiped off and the aesthetic appearance can be maintained.

[0004] In particular, kitchens and dining rooms, where food contaminants such as oils like salad oil and tempura oil, and colored condiments like soy sauce and sauces are likely to spill or splash and adhere to surfaces; children's rooms, where mud, crayons, and markers are likely to be brought in from outside on children's hands, feet, and clothes; and toilets, washrooms, and laundry rooms, where water and soapy solutions are likely to splash during flushing, washing, and laundry, require a much higher level of stain resistance against everyday contaminants than typical living rooms and bedrooms, and ordinary urethane coatings used in ordinary cosmetic materials are simply not sufficient.

[0005] One method for imparting a high degree of stain resistance to the surface of a decorative material is to form a stain-resistant layer on the surface by applying a silicone resin or fluororesin with low surface tension (see, for example, Patent Document 1). However, this method can lead to problems such as the surface becoming extremely slippery, resulting in poor tactile feel and handling, and insufficient surface hardness making it susceptible to scratches and abrasion. Therefore, a method of adding silicone oil to a conventional paint film made of urethane resin or the like to create an anti-fouling layer (see, for example, Patent Document 2) has been relatively widely adopted in the past. This is because the main component of the paint film is a conventional cosmetic paint such as urethane resin, so it has sufficient surface properties such as scratch resistance, abrasion resistance, and weather resistance. In addition, some of the silicone oil in the paint film seeps out to the surface of the paint film and forms an oil film, and this oil film prevents contaminants from adhering, thus exhibiting excellent stain resistance.

[0006] However, this oil film is wiped away along with the contaminants, and while sufficient silicone oil is present in the coating, it seeps out again to form a new oil film, restoring stain resistance. However, over time and with repeated wiping, the silicone oil in the coating is lost, and stain resistance is no longer exhibited, posing a challenge in terms of the durability of stain resistance. Furthermore, especially with decorative materials supplied in a rolled state, such as decorative paper, decorative sheets, and wallpaper, the silicone oil that seeps out onto the surface of the coating can transfer to the back of the decorative material, repelling the adhesive when it adheres to the substrate or substrate, causing adhesion inhibition.

[0007] As a means of ensuring sufficient surface properties in the surface coating of decorative materials while providing excellent long-term durability and stain resistance, various methods have already been investigated, including chemically bonding the main resin component of the coating with a silicone component for imparting stain resistance. A typical example is a two-component crosslinking reaction type resin using acrylic resin as the main component and a silicone compound as the curing agent (see, for example, Patent Documents 3 and 4). While it is true that, compared to the original acrylic resin, the introduction of silicone components does indeed improve stain resistance due to a decrease in surface tension, the improvement in stain resistance is often not as significant as when silicone oil is added, perhaps because the silicone components are bound to the two acrylic skeletons as a crosslinking agent and cannot move freely.

[0008] There are also proposed methods using (meth)acrylate-based ionizing radiation-curable resins containing silicone (meth)acrylate compounds (see, for example, Patent Document 5). However, since this method utilizes special curing systems such as electron beams or ultraviolet light, it requires expensive equipment, and its applicability to special shapes where uniform irradiation is difficult, as well as problems such as substrate degradation due to irradiation, often limits its range of application. In addition, ionizing radiation-curable resins have a very high crosslinking density, and the molecular motion of the silicone component is hindered by the extremely rigid three-dimensional crosslinked structure of the cured product, making it often difficult to obtain a sufficient improvement in stain resistance. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 11-58614 [Patent Document 2] Japanese Patent Application Publication No. 10-58611 [Patent Document 3] Japanese Patent Application Publication No. 5-222819 [Patent Document 4] Japanese Patent Application Publication No. 5-246001 [Patent Document 5] Japanese Patent Application Publication No. 5-86306 [Overview of the project] [Problems that the invention aims to solve]

[0010] This invention was made to solve the problems of the prior art described above, and its purpose is to provide a stain-resistant decorative material (decorative sheet) that not only has excellent stain resistance to various household pollutants, but also excellent aesthetic qualities such as tactile feel and design. [Means for solving the problem]

[0011] The stain-resistant decorative material (decorative sheet) of the present invention is characterized by improved stain resistance and design due to the uneven surface shape applied to its surface. Specifically, a stain-resistant decorative material (decorative sheet) according to one aspect of the present invention has at least a surface protection layer on a base layer, and the arithmetic mean roughness (Ra0.008) measured perpendicular to the film formation direction with respect to the surface side of the surface protection layer, with a cutoff value λc of 2.5 mm, a cutoff value λs of 8 μm, and an evaluation length of 10 mm, is 10 μm or less, and the average length RSm of the roughness curve elements and the ten-point average roughness RzJIS satisfy the conditions of the following equation (1). 5 ≦ RSm / RzJIS ≦ 40 (1)

[0012] Furthermore, we discovered that by encapsulating a nucleating agent that improves the crystallinity of polypropylene within a vesicle having a single-layer outer film, and adding this nucleating agent vesicle to the polypropylene resin, and by further investigating and conducting various experiments on the manufacturing process, we can provide a decorative sheet with improved scratch resistance by optimizing the Martens hardness. Specifically, a decorative sheet according to one aspect of the present invention comprises a base layer having a core layer containing an inorganic pigment and a polypropylene resin, and a skin layer formed on both sides of the core layer and containing a polypropylene resin, wherein the skin layer may be formed by adding nucleating agent vesicles, in which nano-sized nucleating agents are encapsulated in vesicles having a single-layer outer film, to the polypropylene resin.

[0013] 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. Moreover, a nucleating agent is a substance that serves as a crystallization starting point in a crystalline polypropylene resin.

Advantages of the Invention

[0014] According to one aspect of the present invention, by controlling the surface uneven shape applied on the base material, it is possible to provide a decorative sheet excellent in stain resistance and design (touch feeling and design feeling).

Brief Description of the Drawings

[0015] [Figure 1] It is a cross-sectional view showing the configuration of a decorative sheet according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view showing the configuration of another decorative sheet according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thicknesses of each layer, etc. are different from the actual ones. Further, the embodiments shown below are 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 as the following. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

[0017] The decorative material of the present embodiment includes at least a base material B and a decorative sheet 10. Hereinafter, the base material B and the decorative sheet 10 of the present embodiment will be described in detail. In FIGS. 1 and 2, the symbol B represents a substrate. The substrate B is a substrate to which the decorative sheet 10 described later is bonded. The substrate B is not particularly limited, and examples thereof include wood boards, inorganic boards, metal plates, composite boards made of a plurality of materials, and the like. Further, a primer layer, a concealment layer, or the like may be provided between the decorative sheet 10 and the substrate B as appropriate.

[0018] The decorative sheet 10 of this embodiment comprises, for example, a base layer 1, a pattern layer 2, a transparent resin layer 3, and a top coat layer 4 in this order. The following describes each layer that makes up the decorative sheet 10. <Base material layer 1> The base layer 1 consists of a colored polypropylene film with a three-layer structure, for example, a core layer 1a at the center with skin layers 1b on both sides thereof. The core layer 1a is mainly made of polypropylene resin, and may be colored by mixing inorganic pigments into the polypropylene resin. The skin layer 1b may also be formed containing polypropylene resin. The skin layer 1b does not necessarily contain inorganic pigments.

[0019] (Polypropylene resin) The polypropylene resin used in the core layer 1a is preferably a highly flexible random polypropylene resin with ethylene content, or a known amorphous polypropylene resin mixed with the random polypropylene resin or a highly crystalline homopolypropylene resin, taking into consideration the dispersibility of the inorganic pigment. The polypropylene resin used in the skin layer 1b is preferably high-crystalline homopolypropylene because it is not necessary to consider the dispersibility of inorganic pigments, but it is not limited to high-crystalline homopolypropylene. In applications where processability such as bending is more important, high-crystalline homopolypropylene can be mixed with, for example, random polypropylene resin having an ethylene content within a predetermined range or known amorphous polypropylene resin.

[0020] The skin layer 1b of the substrate layer 1, which is made of colored polypropylene film, has a Martens hardness of 80 N / mm². 2 More than 120N / mm 2 The following ranges are preferable, and the core layer 1a has a Martens hardness of 50 N / mm². 2 More than 80N / mm 2 The following range is preferable.

[0021] The Martens hardness of core layer 1a is 50 N / mm². 2If it is less than this value, it is highly likely to be difficult to ensure the practical scratch resistance. On the other hand, when the martensite hardness of the core layer 1a is 80 N / mm 2 exceeds this value, due to the excessively high crystallinity, there is a risk of problems such as whitening and cracking in bending processing, or cracking in the impact resistance test. Also, when the martensite hardness of the skin layer 1b is 80 N / mm 2 is less than this value, it is highly likely to be difficult to ensure the practical scratch resistance. On the other hand, when the martensite hardness of the skin layer 1b is 120 N / mm 2 exceeds this value, due to the excessively high crystallinity, even when using a nucleating agent vesicle, there is a risk of problems such as whitening and cracking in bending processing, or cracking in the impact resistance test.

[0022] The preferable range of the martensite hardness of the core layer 1a of the base material layer 1 is 60 N / mm 2 or more and 80 N / mm 2 or less. The preferable range of the martensite hardness of the skin layer 1b of the base material layer 1 is 80 N / mm 2 or more and 100 N / mm 2 or less. By setting the range in this way, it is possible to achieve excellent compatibility in terms of scratch resistance, impact resistance, and bending processing. Here, the martensite hardness is a kind of index indicating the hardness of a substance. A load is applied to an indenter and pressed into the surface of a sample, and the depth of the depression (indentation) formed at that time (penetration depth) is measured, and it is defined as the quotient of the penetration force calculated from the load and the surface area of the depression calculated from the penetration depth. The measurement is carried out by the method defined in ISO14577.

[0023] The arithmetic mean height Ra and the ten-point mean roughness Rz of the top coat layer (surface protection layer) 4 indicate the information in the height direction of the unevenness formed on the top coat layer 4. The average length RSm is the average value of the length Xs of the profile curve elements at the reference length, and indicates the lateral information such as the pitch interval of the unevenness formed on the surface of the top coat layer 4. When Ra and Rz are small, the surface irregularities formed on the topcoat layer 4 are small, resulting in a shape that makes it difficult for contaminants to adhere. When RSm is large, the pitch between the irregularities formed on the surface of the topcoat layer 4 is wide, resulting in a shape that makes it easy to wipe away contaminants even if they get inside.

[0024] In this embodiment, when the Ra of the topcoat layer 4 is greater than 10 μm and the RSm / RzJIS is less than 5, the surface of the topcoat layer 4 has large irregularities and a dense shape with a narrow pitch between the irregularities. Therefore, if contaminants adhere firmly, they cannot be easily wiped off, and the surface cannot be said to have excellent stain resistance. Furthermore, if RSm / RzJIS is greater than 40, it often results in a smooth, uneven surface, which can compromise the aesthetic appeal. Furthermore, the Ra of the top coat layer 4 is preferably 1.0 μm or greater. In other words, the Ra of the top coat layer 4 in this embodiment is preferably within the range of 1.0 μm to 10 μm. If the Ra of the top coat layer 4 is less than 1.0 μm, the design quality will be inferior, which may impair the commercial value of the decorative sheet 10.

[0025] Here, Ra was measured using a surface roughness meter (Mitutoyo Corporation, model SJ-310) according to the measurement method compliant with JIS B0601:2001, with a cutoff value λc of 2.5 mm, a cutoff value λs of 8 μm, and an evaluation length of 10 mm. Measurements were taken in the direction of the pattern if present, and perpendicular to the film formation direction if absent. Measurements were taken at five arbitrary points, and the average value was used as the measured value. The same procedure was followed for RSm and RzJIS.

[0026] Methods for adjusting the surface roughness of the top coat layer 4 include, for example, (1) adding an inorganic filler to the top coat layer 4, and (2) creating an embossed shape using an embossing plate. In this embodiment, the surface roughness of the top coat layer 4 is adjusted by method (2). In this embodiment, the thickness of the substrate layer 1, which is made of colored polypropylene film, may be within the range of 40 μm to 200 μm.

[0027] If the thickness of the base layer 1 is less than 40 μm, even if the Martens hardness of the skin layer 1b is set to the optimal range, the film strength will be insufficient, making it difficult to suppress defects during printing and deterioration of scratch resistance, and also difficult to maintain surface smoothness during wrapping. On the other hand, if the thickness of the base layer 1 exceeds 200 μm, there is a high possibility of defects such as whitening and cracking occurring during bending, and during wrapping, the ability to follow the edges and laminated parts of the wood substrate becomes significantly worse, resulting in insufficient adhesive strength, which may lead to defects such as delamination over time. A more suitable range for the thickness of the base material layer 1 is between 60 μm and 150 μm. Within this range, it is possible to achieve a sufficient balance between defects during printing, surface smoothness during wrapping, scratch resistance, and bending.

[0028] Regarding the thickness of the skin layer 1b and core layer 1a of the base layer 1, it is preferable that the thickness of the core layer 1a is within the range of 3 to 50 times the thickness of the skin layer 1b. If the thickness of the core layer 1a is less than 3 times, it is difficult to satisfy the minimum required opacity for a decorative sheet. If the thickness of the core layer 1a exceeds 50 times, the thickness of the skin layer 1b becomes relatively too small, resulting in insufficient film strength, and even if the Martens hardness is set to the optimal range, it is difficult to suppress defects during printing and deterioration of scratch resistance. A more suitable range for the thickness of the core layer 1a is when the thickness of the core layer 1a is between 10 and 40 times the thickness of the skin layer 1b. By keeping the thickness within this range, it is possible to achieve a sufficient balance between opacity, defects during printing, surface smoothness during wrapping, scratch resistance, and bendability.

[0029] In this embodiment, as described above, it is preferable to use a highly crystalline polypropylene resin as the polypropylene resin used for the skin layer 1b. 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 30% to 100% by mass relative to the total mass of the polypropylene resin. The crystallization temperature of polypropylene resin is generally considered to be in the range of 100°C to 130°C, and when a nucleating agent is added, it is in the range of 110°C to 140°C. In the skin layer 1b of the colored polypropylene film in the decorative sheet 10 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 achieving a Martens hardness of 80 N / mm². 2 More than 120N / mm 2 The following ranges are used for adjustment. Note that if the content of highly crystalline homopolypropylene resin is less than 30% by mass, the crystallinity will be insufficient, and even with controlled cooling processes, the Martens hardness may fall below the optimal range.

[0030] 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.

[0031] (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.

[0032] (Nucleating agent vesicles) Furthermore, the skin layer 1b of the base layer 1 may contain 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, which is encapsulated in a vesicle having a single-layer outer film. When a nucleating agent is included in the skin layer 1b of the base layer 1, the crystallinity of the polypropylene resin can be improved, and the scratch resistance (scratch resistance) of the base layer 1 can be improved. In this embodiment, the nucleating agent in the resin constituting the skin layer 1b of the base layer 1 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.

[0033] Because nano-sized nucleating agents have extremely small particle sizes, the number of nucleating agents per unit volume and their 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 polypropylene resin, the growing edge of the crystal immediately comes into contact with the edge of a 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 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, thus enabling the creation of a colored polypropylene film that suppresses cracking and whitening during bending.

[0034] In this case, when a nucleating agent is simply added, the nucleating agent in the polypropylene resin undergoes secondary aggregation, increasing the particle size. Furthermore, the number of crystal nuclei relative to the added nucleating agent may be significantly less than when it is added as nucleating agent vesicles. This can lead to an increase in the average particle size of spherulites in the crystalline portion of the polypropylene resin, making it difficult to suppress cracking and whitening during bending. Therefore, improving elastic modulus through increased crystallinity and achieving good processability may not be compatible.

[0035] In this embodiment, the skin layer 1b of the base layer 1, which is made of a colored polypropylene film and constitutes the decorative sheet 10, only needs to be added in an amount of 0.05 parts by mass or more and 0.5 parts by mass or less, when converted to an amount of nucleating agent added per 100 parts by mass of polypropylene resin as the main component, and it is preferable that the amount of nucleating agent vesicles added is in the range of 0.1 parts by mass or more and 0.3 parts by mass or less. If the amount of nucleating agent vesicles added is less than 0.05 parts by mass, the degree of crystallinity may not improve sufficiently, and the required elastic modulus (hardness) may not be reached. On the other hand, if the amount of nucleating agent vesicles added exceeds 0.5 parts by mass, the crystal nuclei are excessive, which inhibits spherulite growth, and as a result, the degree of crystallinity may not improve sufficiently, and the required elastic modulus (hardness) may not be reached.

[0036] Furthermore, methods for nano-sizing nucleating agents include, for example, a solid-phase method that primarily uses mechanical grinding to obtain nano-sized particles of the nucleating agent, and a method that uses a solution of the nucleating agent to nano-size particles. Methods such as liquid-phase methods for synthesizing and crystallizing particles, and gas-phase methods for synthesizing and crystallizing nano-sized particles from nucleating agents or gases / vapors composed of nucleating agents can be used as appropriate. 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.

[0037] 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.

[0038] 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.

[0039] 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. In this embodiment, a nucleating agent vesicle whose outer membrane is composed of a substance containing biolipids such as phospholipids is referred to as a nucleating agent liposome. 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.

[0040] 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.

[0041] Furthermore, the outer membrane of the liposome may be formed from a mixture of phospholipid and a dispersant. In the decorative sheet 10 of this embodiment, it is preferable that the nucleating agent vesicle be a radical scavenging liposome having an outer membrane made of phospholipid, and by making the outer membrane from phospholipid, the compatibility between the resin material, which is the main component of the substrate layer 1, and the vesicle can be improved.

[0042] 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.

[0043] As described above, one of the features (specific features of the invention) of the decorative sheet 10 of this embodiment is that "the skin layer 1b of the base layer 1 contains a nucleating agent encapsulated in vesicles." Adding the nucleating agent to the resin composition while it is encapsulated in vesicles dramatically improves the dispersibility of the nucleating agent in the resin material, i.e., in the skin layer 1b of the base layer 1. However, directly identifying this feature in the structure and properties of the finished decorative sheet 10 may be difficult depending on the circumstances and can be considered impractical. 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 10, the nucleating agent is highly dispersed in the skin layer 1b of the base layer 1. However, in the process of manufacturing the decorative sheet 10 after the base layer 1 is made by adding a nucleating agent in the form of vesicles to the resin composition constituting the skin layer 1b of the base layer 1, 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 the crushed or chemically reacted outer membrane varies depending on the processing steps of the decorative sheet 10. In situations where the nucleating agent is not contained by the outer membrane, it is difficult to specify the physical properties themselves within a numerical range, and it may also be difficult to determine whether the constituent material of the crushed 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 conventional invention in that the nucleating agent is blended in a highly dispersed manner within the substrate layer 1, it is conceivable that it may be impractical to determine, based on numerical ranges and measurements of the structure and characteristics of the decorative sheet 10, whether this is due to the nucleating agent being added in the form of vesicles containing the nucleating agent. Furthermore, the nucleating agent vesicle with the above configuration may also be included in the transparent resin layer 3.

[0044] <Pattern Layer 2> A pattern layer 2 can be provided on the surface of the colored polypropylene film (base layer 1) to add a pattern to the decorative sheet 10. Examples of patterns that can be used include wood grain, stone, sand, tile, brick, fabric, leather, and geometric shapes. Furthermore, a base solid ink layer (not shown) may be provided between the base layer 1 and the pattern layer 2, depending on the desired degree of design. The base solid ink layer is provided so as to cover the entire surface of the base layer 1. The base solid ink layer may also be made up of two or more layers as needed for opacity, etc. Furthermore, the pattern layer 2 may be formed by laminating as many layers as necessary to express the desired design. In this way, the pattern layer 2 and the base solid ink layer are formed as desired The design can take many forms depending on the desired expression, but there are no particular limitations.

[0045] The constituent materials of the base ink layer and the pattern layer 2 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.

[0046] 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 2 in order to impart various functions. Here, the base solid ink layer and the pattern layer 2 can be formed by various printing methods such as gravure printing, offset printing, screen printing, electrostatic printing, and inkjet printing. Furthermore, since the base solid ink layer covers the entire surface of the substrate layer 1, it can also be formed by various coating methods such as roll coating, knife coating, microgravure coating, and die coating. These printing 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 them all at once.

[0047] <Transparent resin layer 3> The resin material used as the main component of the transparent resin layer 3 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 of the following (e.g., 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 10, it is preferable to use a highly crystalline polypropylene resin, similar to the skin layer 1b of the base layer 1. In this embodiment, unless otherwise specified, "main component" refers to 90% by mass or more of the material in question.

[0048] When a transparent resin layer 3 is provided, the thickness of the transparent resin layer 3 is in the range of 50 μm to 100 μm. The interior is preferable. If the thickness of the transparent resin layer 3 is less than 50 μm, the effect of improving the scratch resistance of the surface of the transparent resin layer 3 is low, and the significance of providing the transparent resin layer 3 may diminish. If the thickness of the transparent resin layer 3 exceeds 100 μm, defects such as whitening and cracking may occur during bending. However, if a topcoat layer 4 is provided on top of the transparent resin layer 3, the thickness of the transparent resin layer 3 may be less than 50 μm. Furthermore, the resin composition constituting the transparent resin layer 3 may optionally contain various functional additives, 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.

[0049] <Top coat layer 4> If further improvement in scratch resistance or adjustment of gloss is required, a topcoat layer (surface protective layer) 4 can be applied to the surface of the transparent resin layer 3. In this embodiment, the surface shape (uneven shape) of the top coat layer 4 is designed such that, with respect to the surface side of the top coat layer 4, the cutoff value λc is 2.5 mm, the cutoff value λs is 8 μm, and the evaluation length is 10 mm, the arithmetic mean roughness (Ra0.008) measured perpendicular to the film formation direction of the top coat layer 4 in accordance with JIS B0601:2001 is 10 μm or less, and the average length RSm of the roughness curve elements and the ten-point mean roughness RzJIS satisfy the conditions of equation (1) below. 5 ≦ RSm / RzJIS ≦ 40 (1) If the surface shape of the topcoat layer 4 satisfies the above conditions, stain resistance and aesthetic appeal can be improved.

[0050] The main component resin material for the top coat layer 4 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.

[0051] As the main component of the topcoat layer 4, a urethane-based resin material using isocyanate is preferred from the viewpoint of workability, cost, and the cohesive strength of the resin itself. For the isocyanate, 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, to improve surface hardness, it is preferable to use resins that harden with active energy rays such as ultraviolet rays or electron beams. These resins can be used in combination with each other; for example, by using a hybrid type of thermosetting and photocuring resins, surface hardness can be improved, curing shrinkage can be suppressed, and adhesion can be improved.

[0052] A gloss adjuster can be added to the top coat layer 4 to adjust the gloss. Any commercially available, known gloss adjuster may 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, or acrylic with high transparency. In particular, Among fine particles such as lichen and glass, gloss modifiers that are not solid, perfectly spherical particles but rather low-bulk-density particles formed by secondary aggregation of fine primary particles have a high matting effect relative to the amount added. Therefore, by using such gloss modifiers, the amount of gloss modifier added can be reduced.

[0053] Furthermore, functional additives such as antibacterial agents and antifungal agents may be added to the topcoat layer 4 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 4 is preferably within the range of 3 μm to 15 μm. If the thickness of the topcoat layer 4 is less than 3 μm, the effect of improving scratch resistance is low, and the significance of providing the topcoat layer 4 may diminish. If the thickness of the topcoat layer 4 exceeds 15 μm, cracks or fissures may occur during bending, which may cause design problems and deterioration of weather resistance.

[0054] In this embodiment, the tensile modulus of the decorative sheet 10, particularly the tensile modulus of the base material layer 1 alone, may be within the range of 700 MPa to 2000 MPa. If the tensile modulus is less than 700 MPa, it may not be possible to suppress defects during printing or maintain surface smoothness during wrapping. If the tensile modulus exceeds 2000 MPa, the crystallinity is too high, and even when using a nucleating agent vesicle, defects such as whitening or cracking may occur during bending. The preferred range for the tensile modulus is between 1000 MPa and 1800 MPa. By keeping it within this range, it is possible to achieve excellent balance in terms of defects during printing, scratch resistance, surface smoothness during wrapping, and bending.

[0055] "Manufacturing method" A manufacturing example of decorative sheet 10 will be described. A nucleating agent is encapsulated within a vesicle to create a nucleating agent vesicle, and this nucleating agent vesicle is added to a polypropylene resin to produce a resin material for the skin layer. In addition, an inorganic pigment is added to the polypropylene resin to produce a resin material for the core 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. For the polypropylene resin used in skin layer 1b, it is preferable to use a highly crystalline homopolypropylene resin with an isotactic pentad fraction (mmmm fraction) of 95% or more in the proportion of 30% to 100% by mass.

[0056] The resin materials for the base layer described above are individually heated and melted, and then formed into a sheet with a thickness of 40 μm to 200 μm by extrusion molding or the like to form the base layer 1. Although the skin layer 1b and core layer 1a can be molded separately and then bonded together, for example, using dry lamination, to produce the base layer 1, it is simpler and more productive to combine the molten resin in a T-die or feed block before the T-die during extrusion molding and produce the base layer 1 by co-extrusion molding and shaping. At this time, by adjusting the cooling time from the crystallization temperature to the curing completion temperature using a known adjustment method, the Martens hardness of the skin layer 1b of the substrate layer 1 can be set to 80 N / mm². 2 More than 120N / mm 2 The following range will be controlled. In addition, the Martens hardness of the core layer 1a of the base layer 1 will be 50 N / mm². 2 More than 80N / mm 2 Control it within the following range.

[0057] Furthermore, if necessary, a pattern layer 2 is formed on the upper surface of the base layer 1 by printing, and at least one of the transparent resin layer 3 and the top coat layer 4 is formed on top of it by printing. In this case, it is preferable that the thickness of the transparent resin layer 3 be in the range of 50 μm to 100 μm, the thickness of the top coat layer 4 be in the range of 3 μm to 15 μm, and the total thickness of the decorative sheet 10 be in the range of 100 μm to 250 μm. Furthermore, the top coat layer 4 is formed by embossing the surface side of the top coat layer 4, setting the cutoff value λc to 2.5 mm, the cutoff value λs to 8 μm, and the evaluation length to 10 mm, so that the arithmetic mean roughness (Ra0.008) measured perpendicular to the film formation direction in accordance with JIS B0601:2001 is 10 μm or less, and the average length RSm of the roughness curve elements and the ten-point mean roughness RzJIS satisfy the conditions of equation (1) below. 5 ≦ RSm / RzJIS ≦ 40 (1)

[0058] <Functions and other effects> (1) The decorative sheet 10 of this embodiment has a top coat layer 4 on a base layer 1. The arithmetic mean roughness (Ra0.008) measured perpendicular to the film formation direction of the top coat layer 4 with respect to the surface side of the top coat layer 4, with a cutoff value λc of 2.5 mm, a cutoff value λs of 8 μm, and an evaluation length of 10 mm, is 10 μm or less according to JIS B0601:2001, and the average length RSm of the roughness curve elements and the ten-point mean roughness RzJIS satisfy the conditions of the following equation (1). 5 ≦ RSm / RzJIS ≦ 40 (1) With this configuration, even if contaminants get into the irregularities formed on the surface of the decorative sheet 10, the contaminants can be easily wiped away. In addition, because an appropriate level of irregularity is maintained, the aesthetic appeal is not compromised.

[0059] (2) The decorative sheet 10 of this embodiment has a base layer 1 made of a colored polypropylene film having a core layer 1a containing an inorganic pigment and a polypropylene resin, and a skin layer 1b formed of polypropylene resin on both sides of the core layer 1a. The skin layer 1b of the base layer 1 contains a nano-sized nucleating agent, and the nucleating agent is added in the form of nucleating agent vesicles that are enclosed in the outer film and formed into vesicles. The skin layer 1b has a Martens hardness of 80 N / mm 2 More than 120N / mm 2 Within the following range, the core layer 1a has a Martens hardness of 50 N / mm². 2 More than 80N / mm 2The following ranges apply, and the thickness of the substrate layer 1 is within the range of 40 μm to 200 μm. According to this configuration, a nucleating agent that improves the crystallinity of the polypropylene resin is vesicled and added as nucleating agent vesicles, and by further optimizing the Martens hardness and film thickness, a decorative sheet 10 with excellent scratch resistance can be provided.

[0060] (3) In this embodiment, it is preferable that the thickness of the core layer 1a of the decorative sheet 10 is within the range of 3 to 50 times the thickness of one of the skin layers 1b of the base layer 1. This configuration allows for a comfortable balance of scratch resistance, impact resistance, high concealment, and flexibility. (4) In this embodiment, the amount of nucleating agent vesicles added to the skin layer 1b of the base layer 1 of the decorative sheet 10 is preferably within the range of 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 polypropylene resin constituting the skin layer 1b of the base layer 1 is sufficiently improved, ensuring that the required elastic modulus (hardness) is reliably secured.

[0061] (5) In this embodiment, the decorative sheet 10 is preferably a nucleating agent vesicle that 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 1, and the vesicles. (6) In this embodiment, the decorative sheet 10 is preferably formed by encapsulating the nucleating agent vesicle within a vesicle having a single layer film using a supercritical reverse-phase evaporation method. stomach. With this configuration, the degree of crystallinity of the polypropylene resin constituting the skin layer 1b of the base layer 1 is reliably improved, and the required elastic modulus (hardness) can be reliably secured.

[0062] (7) In this embodiment, it is preferable that the decorative sheet 10 has a pattern layer 2 laminated on one side of the base layer 1. This configuration makes it possible to improve the aesthetic appeal of the decorative sheet 10. (8) In this embodiment, the decorative sheet 10 preferably has at least one of the transparent resin layer 3 and the top coat layer 4 laminated on one side of the base layer 1, and the total thickness of the decorative sheet 10 is in the range of 100 μm or more and 250 μm or less. This configuration significantly reduces the ability to conform to the edges and laminated sections of the wood substrate during the wrapping process, resulting in insufficient adhesive strength and thus preventing problems such as delamination over time.

[0063] [Examples] The following describes a specific example of the decorative sheet 10 of this embodiment. For the core layer 1a of the colored polypropylene film, 60 parts by mass of random polypropylene resin with a melt flow rate (MFR) of 12 g / 10 min (230°C) containing 4% ethylene was mixed with 40 parts by mass of titanium dioxide pigment as an inorganic pigment. For the skin layer 1b, 50 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 50 parts by mass of random polypropylene resin with a melt flow rate (MFR) of 12 g / 10 min (230°C) containing 4% ethylene. The films were then co-extruded and shaped using a melt extruder to produce a core layer with a thickness of 100 μm and a skin layer with a thickness of 5 μm. Next, corona treatment was applied to both sides of the substrate layer 1, and a pattern was printed on one side using a two-component curing urethane ink (V180; manufactured by Toyo Ink Mfg. Co., Ltd.) to form the pattern layer 2. Furthermore, a two-component curing urethane topcoat (W184; manufactured by DIC Graphics, application rate 10g / m²) is applied to the surface of the pattern layer 2. 2 A top coat layer 4 was formed by applying ) to obtain a decorative sheet 10.

[0064] The following explains the case where a nucleating agent is added to the skin layer. (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 achieve a supercritical state with a pressure of 20 MPa. Subsequently, the contents of the container were vigorously stirred, and 100 parts by mass of deionized 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.

[0065] As the raw material for the core layer 1a of the colored polypropylene film, 60 parts by mass of random polypropylene resin with a melt flow rate (MFR) of 12 g / 10 min (230°C) and 4% ethylene component are mixed with 40 parts by mass of titanium dioxide pigment as an inorganic pigment. As the raw material for the skin layer 1b, 50 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 are mixed with 4% ethylene component. Fifty parts by mass of random polypropylene resin with a low rate (MFR) of 12 g / 10 min (230°C) and 0.1 parts by mass of the aforementioned nucleating agent vesicles were added as a nucleating agent. Co-extrusion molding and shaping were performed using a melt extruder to produce a film with a core layer thickness of 100 μm and a skin layer thickness of 5 μm. Subsequent processes were the same.

[0066] (Example 1) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 3.7 and a roughness curve element average length RSm / ten-point mean roughness RzJIS of 7.7, which was designated as the decorative sheet 10 of Example 1. (Example 2) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 6.1 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 11.0, which was designated as the decorative sheet 10 of Example 2. (Example 3) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 2.4 and a ratio of the average length of roughness curve elements RSm / ten-point mean roughness RzJIS of 14.1, which was designated as the decorative sheet 10 of Example 3. (Example 4) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 3.8 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 15.0, which was designated as the decorative sheet 10 of Example 4.

[0067] (Example 5) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 5.5 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 18.6, which was designated as the decorative sheet 10 of Example 5. (Example 6) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 2.9 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 21.8, which was designated as the decorative sheet 10 of Example 6. (Example 7) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 4.9 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 22.1, which was designated as the decorative sheet 10 of Example 7.

[0068] (Example 8) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 3.9 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 25.8, which was designated as the decorative sheet 10 of Example 8. (Example 9) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 3.9 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 28.9, which was designated as the decorative sheet 10 of Example 9. (Example 10) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 3.9 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 31.1, which was designated as decorative sheet 10 of Example 10.

[0069] (Example 11) A skin layer 1b was fabricated using polypropylene resin with the aforementioned nucleating agent added. Furthermore, after forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 3.5 and an average length RSm / ten-point mean roughness RzJIS of 7.6, which was designated as the decorative sheet 10 of Example 11. (Example 12) A skin layer 1b was fabricated using polypropylene resin with the aforementioned nucleating agent added. After forming a topcoat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 3.8 and a roughness curve element average length RSm / ten-point mean roughness RzJIS of 33.9, which was designated as decorative sheet 10 of Example 12.

[0070] (Comparative Example 1) A skin layer 1b was fabricated using polypropylene resin with the aforementioned nucleating agent added. After forming a topcoat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 7.8 and a roughness curve element average length RSm / ten-point mean roughness RzJIS of 2.0, which was designated as the decorative sheet 10 of Comparative Example 1. (Comparative Example 2) A skin layer 1b was fabricated using polypropylene resin with the aforementioned nucleating agent added. After forming a topcoat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 1.9 and a roughness curve element average length RSm / ten-point mean roughness RzJIS of 47.9, which was designated as the decorative sheet 10 of Comparative Example 2. (Comparative Example 3) After forming the top coat layer 4, a decorative sheet was prepared with an arithmetic mean roughness Ra of 7.8 and a ratio of average length RSm of roughness curve elements to ten-point mean roughness RzJIS of 2.0, which was designated as the decorative sheet 10 of Comparative Example 3.

[0071] <Surface roughness> The arithmetic mean roughness (Ra 0.008) of the surface of the topcoat layer 4 on the decorative sheet 10 of each example and comparative example was measured using a surface roughness meter (Mitutoyo Corporation, model number: SJ-310) in accordance with the measurement method of JIS B0601:2001, with a cutoff value of 0.008 mm and an evaluation length of 10 mm. Measurements were taken at five arbitrary points along a direction perpendicular to the film formation direction, and the average value was taken as the measured value. The measurement results are shown in Table 1.

[0072] <Stain resistance> Blue ink (marker) was applied to the decorative sheet 10 of each example and comparative example, and after being left for 4 hours, it was wiped off with a neutral detergent or alcohol. Alternatively, in the same manner, crayon, neutral detergent, chemical (ethanol), or food (soy sauce) was applied, and after being left for 6 hours, it was wiped off. The condition of the dirt after wiping was visually observed and evaluated according to the evaluation criteria below. The evaluation results are shown in Table 1. Furthermore, a rating of ++ or higher indicates that there are no problems in practical use. +++: No residue left behind ++: Minor staining +: There are some remaining stains. -: Many stains remain

[0073] <Design and Tactile Sensibility> Twenty subjects visually observed the surface of the decorative sheet 10 for each example and comparative example, then touched the surface with their hands and evaluated it according to the evaluation criteria below. The evaluation results are shown in Table 1. A rating of △ or higher indicates that there are no problems in actual use. ○: More than 10 people felt that it had a smooth texture and good design. △: 5 to 10 people found the tactile sensation to be pleasant and the design to be good. ×: Fewer than 5 people feel that the tactile feel or design is good.

[0074] <Scratch resistance> Scratch resistance was evaluated by conducting a pencil hardness test. In the pencil hardness test, an HB pencil was used, and the pencil angle was fixed at 45±1° against the decorative sheet 10 of each example and comparative example. 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 according to the evaluation criteria below. The evaluation results are shown in Table 1. A rating of ○ or higher indicates that there are no problems in practical use. A rating of △ or higher means that problems do not occur, although applications are limited to, for example, furniture or high, vertical surfaces that are not touched by people. A rating of ○ or higher is desirable. ◎: No scars or marks whatsoever ○: Slight pencil marks are visible. △: Pencil marks are visible. ×: Pencil marks and tears in the colored polypropylene film are visible.

[0075] [Table 1]

[0076] As can be seen from Table 1, the decorative sheets 10 of Examples 1 to 12 have optimal surface roughness, resulting in no problems with stain resistance or design, and also yielding good results in pencil hardness tests. In particular, Examples 11 and 12 used a substrate layer containing a nucleating agent, resulting in very good results in pencil hardness tests.

[0077] On the other hand, in the decorative sheets 10 of Comparative Examples 1 and 2, although the Martens hardness was suitable and scratch resistance was good, the surface roughness was outside the range. In Comparative Example 1, the RSm / RzJIS was 2, and the surface had a large and densely packed structure, making it difficult to easily wipe away strongly adsorbed contaminants, leaving stains behind. Furthermore, in Comparative Example 2, the RSm / RzJIS ratio was 47.9, indicating that while the surface had few irregularities and a gentle structure, making it easy to wipe away contaminants, the aesthetic appeal and pleasant tactile feel were compromised. Finally, in Comparative Example 3, not only the surface roughness but also the Martens hardness fell outside the desirable range, resulting in impaired stain resistance and aesthetic appeal, as well as reduced scratch resistance.

[0078] From the above, it has become clear that the decorative sheets 10 of Examples 1 to 12 do not cause any defects as a surface of the base material layer 1, and are decorative sheets 10 that possess stain resistance and design properties. 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. [Industrial applicability]

[0079] The decorative sheet according to the present invention can be used for interior and exterior materials of buildings such as houses, building materials such as joinery and fixtures, furniture and fixtures, housing equipment and home appliances, etc. In particular, the decorative sheet according to the present invention is suitable for semi-exterior applications such as exterior materials for eaves and entrance doors that are subject to some degree of wind and rain, and for applications such as children's rooms, kitchens and dining rooms, and washrooms where wipeability against magic markers and household contaminants, water repellency, and stain resistance are required. [Explanation of Symbols]

[0080] 10 decorative sheets 1 Base material layer 2 Image Layers 3 Transparent resin layer 4. Top coat layer B substrate

Claims

1. A decorative sheet having at least a surface protective layer on a base layer, The surface of the aforementioned surface protective layer was measured perpendicular to the film formation direction, with a cutoff value λc of 2.5 mm, a cutoff value λs of 8 μm, and an evaluation length of 10 mm, in accordance with JIS B0601:2001. (1) The arithmetic mean roughness (Ra 0.008) is 10 μm or less, (2) The average length RSm and the ten-point average roughness RzJIS of the roughness curve elements satisfy the conditions of equation (1) below. The substrate layer comprises a core layer containing an inorganic pigment and a polypropylene resin, and skin layers formed on both sides of the core layer and containing a polypropylene resin. The Martens hardness of the aforementioned skin layer is 80 N / mm². ２ 120N / mm or more ２ The following range: The Martens hardness of the core layer is 50 N / mm². ２ 80N / mm or more ２ A decorative sheet characterized by being within the following range. 5≦RSm / RzJIS≦40...(1)

2. The decorative sheet according to claim 1, characterized in that the thickness of the base material layer is within the range of 40 μm to 200 μm.

3. The decorative sheet according to claim 1, characterized in that the thickness of the core layer is within the range of 3 times or more and 50 times or less the thickness of one of the skin layers.

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