JP7622361B2 - Decorative sheet - Google Patents

Description

The present invention relates to decorative sheets used for the surface decoration of interior and exterior buildings, fixtures, furniture, construction materials, flooring materials, etc., and in particular to technology suitable for decorative sheets for fixtures and construction materials.

It is preferable that the decorative sheet has scratch resistance and processability, particularly when used as a decorative sheet for fittings and fixtures.
Here, an example of a decorative sheet that takes scratch resistance into consideration is the decorative sheet described in Patent Document 1.
By the way, a decorative sheet is attached to the surface of a substrate such as a wooden substrate, a metal substrate, or a non-flammable substrate to form a decorative board, and the decorative sheet imparts a design to the decorative board according to the purpose. Therefore, the decorative sheet needs to cover the surface of the substrate completely so that it cannot be seen as necessary. In this case, it is necessary to use a decorative sheet that is colored at least with a pigment and has a hiding property.

JP 2013-83139 A

In recent years, due to the expansion of applications of decorative boards using decorative sheets and the increasing sophistication of consumer awareness of quality, there is a demand for the sheets to have both scratch resistance, bending workability, and hiding power.
To meet the above requirements, it is necessary to make the decorative sheet thicker or harder in order to improve scratch resistance, but either of these approaches results in a deterioration of bending workability, and so there is a trade-off between these two.
Furthermore, in order to achieve high hiding power, it is necessary to increase the concentration of the inorganic pigment, but in this case, there is a risk of powdery lifting on the surface of the base layer and a decrease in interlayer adhesion.

The scratches here can be deep scratches that gouge the surface, or shallow scratches that cause gloss changes. A gloss change is noticeable even to the naked eye when there is a change of 10% or more in the 60° gloss value. In many cases, the scratches that cause gloss changes are shallow scratches with a depth of 100 μm or less. Deep scratches that gouge the surface can be prevented by increasing the hardness of the resin. On the other hand, shallow scratches that cause gloss changes are difficult to prevent simply by increasing the hardness of the resin, and another solution is required.

The present invention was made with the above points in mind, and aims to provide a decorative sheet that combines scratch resistance, bending workability, and hiding power, and in particular, reduces gloss changes caused by deep, gouged scratches and shallow scratches.

The inventors discovered the present invention by adding a nucleating agent vesicle, which improves the crystallinity of polypropylene, to a polypropylene resin for the base layer, which can be used as a decorative sheet and has further improved scratch resistance, by encapsulating the nucleating agent in a vesicle having a single-layer outer membrane to form a vesicle, and then adding the nucleating agent vesicle to the polypropylene resin. They also conducted various studies and experiments on the manufacturing process to find an optimum range for the Martens hardness, and by examining the gloss regulator and abrasion resistance agent to be added to the surface protective layer.

In order to solve the problems, a decorative sheet according to one embodiment of the present invention comprises a substrate layer and a surface protective layer formed on the substrate layer, the substrate layer having a core layer formed by mixing an inorganic pigment into a polypropylene resin and a skin layer formed of polypropylene resin on both sides of the core layer, the skin layer being formed by adding nucleating agent vesicles having a single-layer outer membrane and a nano-sized nucleating agent encapsulated in the vesicle to the polypropylene resin, the skin layer having a Martens hardness in the range of 50 N/ ^mm2 to 120 N/ ^mm2 , the substrate layer having a thickness in the range of 40 μm to 200 μm, the surface protective layer having a lower layer formed on the substrate layer side and an upper layer formed on the lower layer, the lower layer containing a spherical gloss adjuster and a spherical anti-wear agent.

According to one aspect of the present invention, a nucleating agent that improves the crystallinity of polypropylene is converted into a vesicle and added as a nucleating agent vesicle to optimize the Martens hardness, layer structure, and film thickness of the base layer, and a spherical gloss regulator and a wear-resistant agent are added to the surface protection layer, providing a decorative sheet that achieves both scratch resistance, bending workability, and hiding properties, and that reduces gloss changes caused by shallow scratches and deep scratches that gouge the surface.

FIG. 1 is a cross-sectional view illustrating a configuration of a decorative sheet according to an embodiment of the present invention.

Hereinafter, the configuration of a decorative sheet according to an embodiment of the present invention will be described with reference to the drawings.
Here, the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc. are different from the actual ones. Furthermore, 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 described below. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.

(composition)
As shown in Fig. 1, the decorative sheet 1 of this embodiment is constructed by laminating a pattern layer 3 and a surface protective layer 4 in this order on the front side, which is one surface of a base layer 2. The decorative sheet 1 of this embodiment is provided with a concealing layer 5 and a primer layer 6 on the back side, which is the other surface of the base layer (original fabric layer) 2. The concealing layer 5 and the primer layer 6 may be omitted.
The decorative sheet 1 of this embodiment is preferably designed so that its layer thickness is in the range of 100 μm to 250 μm. If the layer thickness of the decorative sheet 1 is less than 100 μm, the strength of the decorative sheet 1 as a whole is insufficient, which may cause problems with smoothness during wrapping. If the layer thickness of the decorative sheet 1 is more than 250 μm, the strength of the decorative sheet 1 as a whole is too high, which may cause problems during bending.

Furthermore, in order to improve the design of the decorative sheet 1 of this embodiment, the surface of the base layer 2 facing the pattern layer 3 may be provided with an uneven shape by embossing.
1, the decorative sheet 1 of this embodiment is laminated to a substrate B to form a decorative material 11. The substrate B is not particularly limited, but may be, for example, a wood board, an inorganic board, a metal plate, or a composite board made of multiple materials.

<Base layer 2>
The base layer 2 is, for example, a three-layer colored polypropylene film having a core layer 2a and skin layers 2b on both sides of the core layer 2a. The core layer 2a is mainly made of polypropylene resin, and is colored by mixing inorganic pigment into the polypropylene resin. The skin layer 2b is formed by containing polypropylene resin, but does not contain inorganic pigment.
Furthermore, in order to increase crystallinity, a nano-sized nucleating agent is added to the skin layer 2b of the base layer 2. In this embodiment, the nano-sized nucleating agent is added in the form of nucleating agent vesicles.

(Polypropylene resin)
The polypropylene resin used for the core layer 2a is preferably a highly flexible random polypropylene resin having an ethylene content, or a mixture of a known amorphous polypropylene resin with a random polypropylene resin or a homopolypropylene resin with high crystallinity, taking into consideration the dispersibility of the inorganic pigment.
The polypropylene resin used for the skin layer 2b is preferably a highly crystalline homopolypropylene because it is not necessary to consider the dispersibility of the inorganic pigment, but is not limited to the highly crystalline homopolypropylene. In applications where processability such as bending is more important, for example, a random polypropylene resin having an ethylene content within a predetermined range or a known amorphous polypropylene resin can be mixed with the highly crystalline homopolypropylene.
The skin layer 2b of the base layer 2 made of a colored polypropylene film has a Martens hardness adjusted to be within the range of 50 N/mm2 or ^more and 120 N/mm2 or ^less .

If the Martens hardness of the skin layer 2b is less than 50 N/ ^mm2 , it is highly likely that it will be difficult to ensure the scratch resistance (especially deep scratches) required for practical use. On the other hand, if the Martens hardness of the skin layer 2b is more than 120 N/ ^mm2 , the crystallinity will be too high, and even if a nucleating agent vesicle is used, problems such as whitening and cracking may occur during bending.
The Martens hardness of the skin layer 2b of the base layer 2 is preferably in the range of 70 N/mm2 or ^more and 100 N/mm2 or ^less . By setting the Martens hardness in this range, it is possible to achieve excellent resistance to scratching (especially deep scratches) and excellent bending workability.

Here, Martens hardness is a kind of index showing the hardness (hardness) of a substance, and is defined as the quotient of the indentation force calculated from the load and the surface area of the indentation calculated from the indentation depth, which is calculated by applying a load to an indenter and pressing it into the surface of a sample, and measuring the depth (indentation depth) of the indentation (impression) formed at that time. The measurement is performed according to the method specified in ISO14577.
It is also important that the thickness of the base layer 2 made of a colored polypropylene film is within the range of 40 μm or more and 200 μm or less.

When the thickness of the base layer 2 is less than 40 μm, even if the Martens hardness of the skin layer 2 b is in the optimum range, the film strength is insufficient, making it difficult to suppress deterioration of scratch resistance. On the other hand, when the thickness of the base layer 2 is more than 200 μm, problems such as whitening and cracking may occur during bending.
A more preferable range for the thickness of the base layer 2 is 60 μm or more and 150 μm or less. Within this range, scratch resistance (particularly deep scratches) and bending workability can be achieved with a sufficient margin.

The thickness of the skin layer 2b and the core layer 2a of the base layer 2 is preferably within a range of 3 to 50 times the thickness of one of the skin layers 2b. If the thickness of the core layer 2a is less than 3 times, it is difficult to satisfy the minimum required concealment of a decorative sheet. If the thickness of the core layer 2a is more than 50 times, the thickness of the skin layer 2b becomes too small relatively, resulting in insufficient film strength, and it is difficult to suppress deterioration of scratch resistance (especially deep scratches) even if the Martens hardness is in the optimal range.

A more preferable range of the thickness of the core layer 2a is 10 times or more and 40 times or less the thickness of the skin layer 2b. By setting the thickness in this range, it is possible to achieve a sufficient balance between the concealment property, the scratch resistance (especially against deep scratches), and the bending workability.
In this embodiment, it is preferable to use a polypropylene resin having high crystallinity as the polypropylene resin used for the skin layer 2b. 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 30% by mass to 100% by mass with respect to the mass of the total polypropylene resin.

The crystallization temperature of polypropylene resin is generally within the range of 100°C to 130°C, and when a nucleating agent is added, it is within the range of 110°C to 140°C. In the skin layer 2b of the colored polypropylene film in the decorative sheet 1 of this embodiment, the Martens hardness is adjusted to within the range of 50 N/ ^mm2 to 120 N/ ^mm2 by controlling the cooling time from the crystallization temperature within this range to the curing completion temperature using a known cooling process. In addition, when the highly crystalline homopolypropylene resin is less than 30% by mass, the crystallinity is insufficient, so that the Martens hardness may be lower than the suitable range even if the cooling process is controlled.

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 measurement (nuclear magnetic resonance measurement) using carbon C (nuclear species) with a mass of 13, and specifies the atomic arrangement, electronic structure, and molecular microstructure of the resin material. The pentad fraction of a crystalline polypropylene resin is the proportion of five propylene units lined up 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, the higher the pentad fraction, the higher the crystallinity.

(Inorganic pigments)
The inorganic pigment may be a known inorganic pigment, typically titanium oxide, for imparting hiding power. Examples of inorganic pigments for coloring include iron-zinc, chromium-antimony, iron-aluminum composite oxides, and iron oxide, and the like, and the blending ratio of these can be freely adjusted according to the desired color. In addition, lustrous materials such as aluminum flakes and pearl pigments may 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 extrudability.

(Nucleating Agent Vesicles)
In addition, the skin layer 2b of the base layer 2 contains a nano-sized nucleating agent. The nano-sized nucleating agent is added to the polypropylene resin in the form of a nucleating agent vesicle encapsulated in a vesicle having a single-layer outer membrane. Since the skin layer 2b of the base layer 2 contains a nucleating agent, the crystallization degree can be improved, and the scratch resistance of the base layer 2 can be improved. In this embodiment, the nucleating agent in the resin constituting the skin layer 2b of the base layer 2 may be encapsulated in a vesicle with a part 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 or more and 750 nm or less, the average particle size is preferably 375 nm or less.

Nano-sized nucleating agents have extremely small particle sizes, so the number of nucleating agents present 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 closer, so that when crystal growth occurs from the surface of one nucleating agent particle added to the polypropylene resin, the end from which the crystal is growing immediately comes into contact with the end of the crystal growing from the surface of another nucleating agent particle adjacent to the one nucleating agent particle, and the ends of the crystals inhibit each other's growth, stopping the growth of each crystal. Therefore, the average particle size of the spherulites in the crystalline part of the crystalline polypropylene resin can be reduced, for example, the spherulite size can be reduced to 1 μm or less. As a result, a colored polypropylene film with high crystallinity and high hardness can be obtained, and the stress concentration between the spherulites that occurs during bending processing can be efficiently dispersed, thereby realizing a colored polypropylene film that suppresses cracking and whitening during bending processing.

Here, if a nucleating agent is simply added, the particle size of the nucleating agent in the polypropylene resin will increase due to secondary aggregation, and the number of crystal nuclei relative to the amount of nucleating agent added may be significantly less than when added as nucleating agent vesicles. This causes the average particle size of the spherulites in the crystalline portion of the polypropylene resin to increase, and cracking and whitening during bending may not be suppressed. Therefore, it may not be possible to achieve both improved scratch resistance and processability by increasing the degree of crystallinity.

The skin layer 2b of the base layer 2 made of a colored polypropylene film constituting the decorative sheet 1 of this embodiment may be added in an amount of 0.05 parts by mass to 0.5 parts by mass in terms of the amount of nucleating agent added per 100 parts by mass of polypropylene resin as the main component, and it is preferable that the nucleating agent vesicle is added in an amount of 0.1 parts by mass to 0.3 parts by mass. If the amount of nucleating agent vesicle added is less than 0.05 parts by mass, the crystallinity may not be sufficiently improved and the required hardness may not be achieved. Furthermore, if the amount of nucleating agent vesicle added is more than 0.5 parts by mass, the spherulite growth may be inhibited due to the excessive crystal nuclei, and as a result, the crystallinity may not be sufficiently improved and the required hardness may not be achieved.

As a method for nano-sizing the nucleating agent, for example, a solid-phase method in which the nucleating agent is mainly mechanically pulverized to obtain nano-sized particles, a liquid-phase method in which nano-sized particles are synthesized or crystallized in a solution in which the nucleating agent or nucleating agent is dissolved, and a gas-phase method in which nano-sized particles are synthesized or crystallized from a nucleating agent or a gas or vapor containing the nucleating agent can be appropriately used. 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 methods, co-precipitation methods, sol-gel methods, liquid-phase reduction methods, and hydrothermal synthesis methods. Examples of gas-phase methods include electric furnace methods, chemical flame methods, laser methods, and thermal plasma methods.

The preferred method for nano-sizing a nucleating agent is supercritical reverse phase evaporation. 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. Carbon dioxide in a supercritical state refers to carbon dioxide in a supercritical state above the critical temperature (30.98°C) and critical pressure (7.3773±0.0030 MPa), and 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.

In addition, a specific nano-processing method using the supercritical reverse phase evaporation method involves first injecting an aqueous phase into a mixed fluid of supercritical carbon dioxide, phospholipids as an outer membrane forming substance, and a nucleating agent as an encapsulating substance, and stirring to generate an emulsion of supercritical carbon dioxide and aqueous phase. Next, the pressure is reduced, causing the carbon dioxide to expand and evaporate, resulting in phase inversion, and generating nanocapsules (nanovesicles) in which the phospholipids cover the surfaces 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 multiple membranes, this supercritical reverse phase evaporation method makes it easy to generate capsules with a single layer membrane, making it possible to prepare capsules with a smaller diameter.

The nucleating agent vesicle can be prepared by, for example, the Bangham method, the extrusion method, the hydration method, the surfactant dialysis method, the reverse phase evaporation method, the freeze-thaw method, the supercritical reverse phase evaporation method, etc. Among these, the supercritical reverse phase evaporation method is particularly preferred.
The outer membrane constituting the nucleating agent vesicle is, for example, composed of a monolayer membrane, and the outer membrane is composed of a substance containing a biological lipid such as a phospholipid.
Nucleating vesicles whose outer membrane is composed of materials that include biological lipids, such as phospholipids, are referred to herein as nucleating liposomes.

Examples of phospholipids that make up the outer membrane include glycerophospholipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, cardiopine, yolk egg lecithin, hydrogenated yolk egg lecithin, soybean lecithin, and hydrogenated soybean lecithin, and sphingophospholipids such as sphingomyelin, ceramide phosphorylethanolamine, and ceramide phosphorylglycerol.

Other substances that form the outer membrane of the vesicle include dispersants such as nonionic surfactants and mixtures of these with cholesterols or triacylglycerol. Among these, examples of nonionic surfactants that can be used include one or more of the following: 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-poly 2-vinylpyridine, polystyrene-polyacrylic acid copolymer, polyethylene oxide-polyethylethylene copolymer, polyoxyethylene-polycaprolactam copolymer, etc. Examples of cholesterols that can be used include cholesterol, α-cholestanol, β-cholestanol, cholestane, desmosterol (5,24-cholestadiene-3β-ol), sodium cholate, cholecalciferol, etc.

The outer membrane of the liposome may 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 having an outer membrane made of phospholipids, and by forming the outer membrane from phospholipids, it is possible to improve the compatibility between the vesicle and the resin material that is the main component of the base layer 2.

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 salts of phosphate esters, metal salts of benzoate, metal salts of pimelate, metal salts of rosin, benzylidene sorbitol, quinacridone, cyanine blue, and talc. In particular, in order to maximize the effect of the nano-processing, it is preferable to use metal salts of phosphate esters, metal salts of benzoate, metal salts of pimelate, and metal salts of rosin, which are non-melting types and can be expected to have good transparency, but if the material itself can be made transparent by the nano-processing, colored quinacridone, cyanine blue, talc, etc. can also be used. In addition, melting benzylidene sorbitol may be appropriately mixed with a non-melting nucleating agent.

As described above, one of the features of the decorative sheet 1 of this embodiment is that "the skin layer 2b of the base layer 2 contains a nucleating agent encapsulated in a vesicle." Adding the nucleating agent encapsulated in a vesicle to the resin composition has the effect of dramatically improving the dispersibility of the nucleating agent in the resin material, i.e., in the skin layer 2b of the base layer 2, but it is expected that it may be difficult to directly identify this feature in the structure or properties of the object in the completed decorative sheet 1 depending on the situation, and it is impractical. The reason is as follows. The nucleating agent added in the form of a vesicle is in a dispersed state with high dispersibility, and the nucleating agent is highly dispersed in the skin layer 2b of the base layer 2 even in the state of the produced decorative sheet 1. However, in the process of producing the decorative sheet 1 after the nucleating agent is added in the form of a vesicle to the resin composition constituting the skin layer 2b of 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, but such treatments may cause the outer membrane of the vesicle containing the nucleating agent to be crushed or chemically reacted, and the nucleating agent is likely 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 a situation in which the nucleating agent is not enclosed by the outer membrane, it is difficult to specify the physical properties themselves in a numerical range, and it is also expected that it may be difficult to determine whether the constituent material of the crushed outer membrane is the outer membrane of the vesicle or a material added separately from the nucleating agent. Thus, the present invention differs from the prior art in that the nucleating agent is highly dispersed in the base layer 2, but it is conceivable that there may be cases where it is impractical to determine within a numerical range the structure and properties of the decorative sheet 1, based on analysis of measurements, to determine whether this is due to the nucleating agent being added in the form of vesicles that encapsulate the nucleating agent.

<Pattern layer 3>
The design layer 3 is a layer of a design printed on the base layer 2 using ink.
The ink binder may be selected from, for example, nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc., either alone or modified. The binder may be water-based, solvent-based, or emulsion type, and may be a one-liquid type or a two-liquid type using a hardener. Furthermore, a method may be used in which a hardening ink is used and the ink is hardened by irradiation with ultraviolet light or electron beams. The most common method is to use a urethane-based ink and harden it with isocyanate. In addition to the binder, for example, pigments, colorants such as dyes, extender pigments, solvents, and various additives contained in normal inks are added to the design layer 3. Examples of versatile pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica.

In addition to applying ink, it is also possible to apply a design to the pattern layer 3 by vapor deposition or sputtering of various metals. In particular, it is preferable that a light stabilizer is added to the ink, which suppresses deterioration of the decorative sheet 1 itself caused by photodegradation of the ink and extends the life of the decorative sheet 1.

<Surface protective layer 4>
The resin material as the main component of the surface protection layer 4 can be appropriately selected from polyurethane, acrylic silicone, fluorine, epoxy, vinyl, polyester, melamine, aminoalkyd, urea, and other resin materials. The form of the resin material is not particularly limited, and may be water-based, emulsion, solvent-based, or the like. The curing method may be appropriately selected from one-liquid type, two-liquid type, ultraviolet curing method, or the like.
As the resin material for the surface protective layer 4, a thermosetting resin is preferable from the viewpoints of workability, cost, adhesion to the pattern layer 3, and the like.

The thermosetting resin is formed, for example, by thermally curing a polymer (polyol) containing a hydroxyl group and an isocyanate compound, which will be described below.
The polyol compound is not particularly limited, but may be used, for example, to impart mechanical properties by elongation of the molecular structure, and may be appropriately selected from, for example, various acrylic polyols, various polyester polyols, various polyether polyols, various polycarbonate polyols, various caprolactone diols, and the like.

When an acrylic polyol is used as the polyol constituting the thermosetting resin, its mass average molecular weight is preferably in the range of 20,000 to 200,000, and more preferably in the range of 20,000 to 100,000. If the mass average molecular weight of the acrylic polyol is less than 20,000, coating during sheet production may be difficult. If the mass average molecular weight exceeds 200,000, the solubility may decrease, and the design may become poor.

As with the above, the isocyanate compound is not particularly limited, but examples thereof include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hydrogenated diphenylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (H6XDI), isophorone diisocyanate (IPDI), etc.

When the thermosetting resin constituting the surface protective layer 4 is composed of an acrylic polyol and an isocyanate curing agent, the glass transition point Tg of the thermosetting resin is preferably 60°C or higher. If the glass transition point of the thermosetting resin is less than 60°C, the desired Martens hardness of the surface protective layer 4 may not be achieved, or coating may be difficult when preparing the sheet.

The surface protective layer 4 has a lower layer 4b on the side of the design layer 3 and an upper layer 4a formed on the lower layer 4b.
The surface protective layer 4 is preferably a resin layer having a Martens hardness in the range of 140 N/mm2 ^{or more} and 200 N/mm2 or ^less . If the resin constituting the surface protective layer 4 has a Martens hardness of less than 140 N/ ^mm2 , deep scratches may be formed in the surface protective layer 4, which is not preferable. Furthermore, if the resin constituting the surface protective layer 4 has a Martens hardness of more than 200 N/ ^mm2 , workability may decrease and whitening may occur when the layer is bent, which is not preferable.

The upper layer 4a of the surface protection layer 4 preferably has a thickness in the range of 2 μm to 10 μm.
In addition, the thickness of the upper layer 4a can be set within the range of 2 μm to 10 μm by applying the coating liquid for the upper layer 4a so that the coating amount after drying is within the range of 2 μm to 10 μm. If the thickness of the upper layer 4a is less than 2 μm, scratch resistance decreases, which is not preferable. Furthermore, if the thickness of the upper layer 4a is thicker than 10 μm, workability decreases and whitening may occur when bending, which is not preferable.

The lower layer 4b of the surface protective layer 4 preferably has a thickness in the range of 2 μm to 10 μm.
In addition, the coating liquid for the lower layer 4b is applied so that the coating amount after drying is in the range of 2 μm to 10 μm, so that the layer thickness of the lower layer 4b can be set in the range of 2 μm to 10 μm. If the layer thickness of the lower layer 4b is less than 2 μm, the scratch resistance decreases, which is not preferable. Also, if the layer thickness of the lower layer 4b is thicker than 10 μm, the processability decreases and whitening may occur when bending, which is not preferable.

The surface protective layer 4 of the decorative sheet 1 of this embodiment contains spherical gloss adjusting agents 10a at least in the lower layer 4b.
The optimum shape of the gloss regulator 10a is spherical. Here, "spherical" includes a perfect sphere or an elliptical shape, and in the case of an elliptical shape, the ratio of the major axis to the minor axis is 2 or less. By making the shape of the gloss regulator 10a spherical, the slipperiness is improved and the scratch resistance (especially for shallow scratches) is improved.

The optimal particle size (average particle size) of the gloss regulator 10a is in the range of 2 μm to 15 μm. Here, the "particle size (average particle size)" may be a value (average value) obtained by measuring the particle size distribution of the particles used, or may be a value obtained by averaging the particle sizes of multiple particles measured from cross-sectional observation of the obtained cosmetic material. Although the measurement methods for both are different, the particle size values obtained are substantially the same. If the particle size of the gloss regulator 10a is less than 2 μm, the effect of adding the gloss regulator 10a may not be achieved, which is not preferable. In addition, if the particle size of the gloss regulator 10a is greater than 15 μm, the gloss regulator 10a may fall off, which is not preferable.

The amount of gloss adjuster 10a added is preferably in the range of 2 parts by mass to 30 parts by mass to 100 parts by mass of the resin that is the main component of the lower layer 4b. More preferably, it is in the range of 2 parts by mass to 20 parts by mass to 100 parts by mass of the resin that is the main component of the lower layer 4b. If the amount of gloss adjuster 10a added is less than 2 parts by mass, the matte effect of the gloss adjuster 10a is small, which is not preferred. Also, if the amount of gloss adjuster 10a added is 30 parts by mass or more, the gloss adjuster 10a may fall off, which is not preferred.

Commercially available particles can be used as the gloss adjuster 10a. For example, organic materials such as PE wax, PP wax, and resin beads, and inorganic materials such as silica, glass, and alumina can all be used as the gloss adjuster 10a. In terms of matting performance, porous silica is preferred. The oil absorption of silica is preferably 200 mL/100 g or more. Silica with a high oil absorption has a high matting performance and is also effective in reducing the amount of matting agent required to be added.

The surface protective layer 4 of the decorative sheet 1 of this embodiment contains spherical anti-wear agents 10b at least in the lower layer 4b.
The optimum shape of the anti-wear agent 10b is spherical. Here, "spherical" includes a perfect sphere or an elliptical shape, and in the case of an elliptical shape, the ratio of the major axis to the minor axis is 2 or less. By making the shape of the anti-wear agent 10b spherical, the slipperiness is improved and the scratch resistance (especially for shallow scratches) is improved.

The optimal particle size (average particle size) of the anti-wear agent 10b is in the range of 2 μm to 15 μm. Here, the "particle size (average particle size)" may be a value (average value) obtained by measuring the particle size distribution of the particles used, or may be a value obtained by averaging the particle sizes of multiple particles measured from cross-sectional observation of the obtained decorative material. Although the measurement methods for both are different, the particle size values obtained are essentially the same. If the particle size of the anti-wear agent 10b is less than 2 μm, the effect of adding the anti-wear agent 10b may not be achieved, which is not preferable. In addition, if the particle size of the anti-wear agent 10b is greater than 15 μm, the anti-wear agent 10b may fall off, which is not preferable.

The amount of the anti-wear agent 10b added is preferably in the range of 1 part by mass to 15 parts by mass to 100 parts by mass of the resin that is the main component of the lower layer 4b. More preferably, it is in the range of 5 parts by mass to 10 parts by mass to 100 parts by mass of the resin that is the main component of the lower layer 4b. If the amount of the anti-wear agent 10b added is less than 1 part by mass, the scratch resistance decreases, which is not preferable. Also, if the amount of the anti-wear agent 10b added is 15 parts by mass or more, it is not preferable because the surfaces of the decorative sheet 1 may be rubbed and scratched when transported together.
The anti-wear agent 10b may be any commercially available known particle. From the viewpoint of abrasion resistance, it is preferable that the anti-wear agent 10b contains at least one of silica and glass. Silica and glass have a suitable hardness and therefore exhibit good scratch resistance.

At least the upper layer 4a of the surface protective layer 4 of the decorative sheet 1 of this embodiment may contain a lubricant.
As the lubricant, a commercially available known lubricant can be used, and examples of the lubricant include wax and surface conditioners.
The amount of lubricant added is preferably in the range of 0.5 parts by mass to 5 parts by mass relative to 100 parts by mass of the resin that is the main component of the upper layer 5a. If the amount of lubricant added is less than 0.5 parts by mass, there is a risk of scratches being caused by rubbing when the surfaces of the decorative sheet 1 are placed together during transportation. If the amount of lubricant added exceeds 5 parts by mass, there is a risk of a large change in gloss due to shallow scratches, resulting in a decrease in scratch resistance.

The surface protective layer 4 of the decorative sheet 1 of this embodiment can be added with functional additives such as antibacterial agents and antifungal agents to impart various functions. In addition, ultraviolet absorbers and light stabilizers can be added to the surface protective layer 4 as necessary. It is common to add any combination of ultraviolet absorbers such as benzotriazoles, benzoates, benzophenones, and triazines, and light stabilizers such as hindered amines.

<Hiding layer 5>
Furthermore, when it is desired to impart concealment properties to the substrate B to the decorative sheet 1, this can be achieved by providing a separate opaque concealment layer 5.
The concealing layer 5 can basically be made of the same material as the picture layer 3, but since the purpose is concealment, it is preferable to use, as the pigment, an opaque pigment, titanium oxide, iron oxide, etc. Also, in order to improve the concealment, it is possible to add metals such as gold, silver, copper, aluminum, etc. Generally, flake-shaped aluminum is often added.

<Primer layer 6>
The primer layer 6 can be made of the same material as the pattern layer 3. Since the primer layer 6 is applied to the back surface of the decorative sheet 1, and considering that the decorative sheet 1 will be wound up in a web form, an inorganic filler may be added to the primer layer 6 to avoid blocking and to increase adhesion with the adhesive. Examples of inorganic fillers include silica, alumina, magnesia, titanium oxide, barium sulfate, etc.

(Production 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, and the prepared nucleating agent vesicle is added to a polypropylene resin to prepare a resin material for a skin layer. Also, an inorganic pigment is added to the polypropylene resin to prepare a resin material for a core 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 for the skin layer 2b is preferably a highly crystalline homopolypropylene resin having an isotactic pentad fraction (mmmm fraction) of 95% or more, which accounts for 30% by mass to 100% by mass.

The above-mentioned resin materials for the base layer are individually heated and melted, and then molded into a sheet having a thickness of 40 μm to 200 μm by extrusion molding or the like to form the base layer 2 .
The skin layer 2b and the core layer 2a can be molded separately and then bonded together, for example, using dry lamination to produce the base layer 2. However, it is simpler and more productive to merge the molten resins in a T-die or a feed block before the T-die during extrusion molding and produce the base layer 2 by co-extrusion molding.
At this time, the Martens hardness of the skin layer 2b of the base layer 2 is controlled within the range of 50 N/ ^mm2 or more and 120 N/mm2 ^{or less} by adjusting the cooling time from the crystallization temperature to the hardening completion temperature using a known adjustment method.

When forming an uneven shape (embossed pattern) on the decorative sheet 1 by embossing, a method can be used in which the sheet is first laminated by the above-mentioned lamination method and then the embossed pattern is applied by heat and pressure, or a method can be used in which an uneven pattern is provided on a cooling roll and the embossed pattern is formed simultaneously with extrusion lamination.
Furthermore, a pattern layer 3 is formed on the upper surface of the base material layer 2 by printing, and a surface protection layer 4 is formed thereon by printing.
In this case, it is preferable that the thickness of the surface protective layer 4 is within a range of 4 μm or more and 20 μm or less, and the total thickness of the decorative sheet 10 is within a range of 100 μm or more and 250 μm or less.

(Action and others)
The decorative sheet 1 of this embodiment comprises a substrate layer 2 and a surface protective layer 4 formed on the substrate layer 2. The substrate layer 2 comprises a core layer 2a formed by mixing an inorganic pigment into a polypropylene resin, and a skin layer 2b formed on both sides of the core layer 2a and made of polypropylene resin. The skin layer 2b is formed by adding, to the polypropylene resin, nucleating agent vesicles in which a nano-sized nucleating agent is encapsulated in a vesicle having a single-layer outer membrane. The skin layer 2b has a Martens hardness of 50 N/mm2 or ^more and 120 N/mm2 or less. ² or less, the thickness of the base layer 2 is within the range of 40 μm or more and 200 μm or less, the surface protective layer 4 has a lower layer 4b formed on the base layer 2 side and an upper layer 4a formed on the lower layer 4b, and the lower layer 4b contains a spherical gloss adjuster 10a and a spherical abrasion-resistant agent 10b, thereby providing a decorative sheet 1 which has both scratch resistance, bending processability and hiding properties and which, with regard to scratches in particular, suppresses gloss changes due to deep scratches that gouge out as well as shallow scratches.

(Modification)
In this embodiment, the spherical gloss adjuster 10a and the spherical anti-wear agent 10b are included in at least the lower layer 4b of the surface protective layer 4, but the present invention is not limited thereto. For example, the spherical gloss adjuster 10a may be included in the upper layer 4a of the surface protective layer 4. In that case, the amount of the gloss adjuster 10a added is preferably in the range of 2 parts by mass to 30 parts by mass with respect to 100 parts by mass of the resin that is the main component of the upper layer 4a. More preferably, it is in the range of 2 parts by mass to 20 parts by mass with respect to 100 parts by mass of the resin that is the main component of the upper layer 4a. If the amount of the gloss adjuster 10a added is less than 2 parts by mass, the matte effect of the gloss adjuster 10a is small, which is not preferable. Also, if the amount of the gloss adjuster 10a added is 30 parts by mass or more, the gloss adjuster 10a may fall off, which is not preferable.

In addition, when the gloss modifier 10a is contained in both the upper layer 4a and the lower layer 4b, the content of the gloss modifier 10a in the upper layer 4a may be greater than the contents of the gloss modifier 10a and the anti-wear agent 10b in the lower layer 4b. In this case, the amount of the gloss modifier 10a added can be reduced to prevent the gloss modifier 10a from falling off.
In addition, when the gloss regulator 10a is contained in both the upper layer 4a and the lower layer 4b, the content of the gloss regulator 10a in the upper layer 4a may be less than the content of the gloss regulator 10a in the lower layer 4b. In this case, the flexibility (pliability) of the entire surface protective layer 4 of the decorative sheet can be increased.

The thickness of the upper layer 4a may be made thinner than the thickness of the lower layer 4b, in which case the flexibility (pliability) of the entire surface protective layer 4 of the decorative sheet can be increased.
The average particle size of the gloss regulator 10a contained in the upper layer 4a may be larger than the average particle size of the gloss regulator 10a contained in the lower layer 4b. In this case, the occurrence of deep scratches can be suppressed, and the occurrence of shallow scratches (changes in gloss) can be effectively suppressed.
The average particle size of the gloss regulator 10a contained in the upper layer 5a may be smaller than the average particle size of the gloss regulator 10a contained in the lower layer 4b. In this case, the occurrence of shallow scratches (changes in gloss) can be suppressed, and the occurrence of deep scratches can be effectively suppressed.

The Martens hardness of the skin layer 2b located on the pattern layer 3 side and the Martens hardness of the skin layer 2b located on the concealing layer 5 side may be the same value or different values. When the Martens hardness of the skin layer 2b located on the pattern layer 3 side and the Martens hardness of the skin layer 2b located on the concealing layer 5 side are different values, the Martens hardness of the skin layer 2b located on the pattern layer 3 side may be higher or lower than the Martens hardness of the skin layer 2b located on the concealing layer 5 side. For example, the Martens hardness of the skin layer 2b located on the pattern layer 3 side may be in the range of 1.1 to 3 times the Martens hardness of the skin layer 2b located on the concealing layer 5 side, or in the range of 0.5 to 0.9 times. Within this range, scratch resistance (especially deep scratches) and bending workability can be achieved with a sufficient margin.

The Martens hardness of the skin layer 2b and the Martens hardness of the core layer 2a may be different values. The Martens hardness of the skin layer 2b may be higher or lower than the Martens hardness of the core layer 2a. For example, the Martens hardness of the skin layer 2b may be in the range of 1.1 to 3 times the Martens hardness of the core layer 2a, or in the range of 0.5 to 0.9 times the Martens hardness of the core layer 2a. Within this range, scratch resistance (especially deep scratches) and bending workability can be achieved with a sufficient margin.

[Example]
Specific examples of the decorative sheet 1 of this embodiment will be described below.
(Method of 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 by the above-mentioned supercritical reverse phase evaporation method, by placing 100 parts by mass of methanol, 70 parts by mass of a phosphate metal salt nucleating agent (Adeka STAB NA-21; manufactured by ADEKA) as a nucleating agent, and 5 parts by mass of phosphatidylcholine as a phospholipid constituting the outer membrane of the vesicle in a high-pressure stainless steel container kept at 60°C and sealing the container, and then injecting carbon dioxide into the container so that the pressure became 20 MPa to create a supercritical state. Thereafter, the container was vigorously stirred and 100 parts by mass of ion-exchanged water was injected. After stirring and mixing for another 15 minutes while maintaining the temperature and pressure in a supercritical state, carbon dioxide was discharged from the container and the pressure was returned to atmospheric pressure, thereby obtaining a nucleating agent vesicle in which a nucleating agent is encapsulated in a vesicle having a monolayer outer membrane made of phospholipid.

Example 1
As the raw material for the core layer 2a of the colored polypropylene film, 60 parts by mass of random polypropylene resin containing 4% ethylene component and having a melt flow rate (MFR) of 12 g/10 min (230 ° C.) was blended with 40 parts by mass of titanium oxide pigment as an inorganic pigment, and as the raw material for the skin layer 2b, 50 parts by mass of highly crystalline homopolypropylene resin containing 4% ethylene component and having a melt flow rate (MFR) of 12 g/10 min (230 ° C.) and 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 50 parts by mass of random polypropylene resin containing 4% ethylene component and having a melt flow rate (MFR) of 12 g/10 min (230 ° C.), and 0.1 part by mass of the above-mentioned nucleating agent vesicle was added as a nucleating agent, and the base material layer 2 consisting of a colored polypropylene film having a core layer thickness of 120 μm and a skin layer thickness of 10 μm was produced by co-extrusion molding using a melt extruder.
Next, both sides of the base layer 2 were subjected to a corona treatment, and a pattern was printed on one side of the base layer 2 using a two-component curing urethane ink (V180; manufactured by Toyo Ink Mfg. Co., Ltd.) to form a pattern layer 3.

The following composition for forming the surface protective layer was used for the pattern layer 3, and the thermosetting composition for the lower layer 4b (amount applied after drying (described as film thickness after drying; the same applies below) 5 μm) and the thermosetting composition for the upper layer 4a (amount applied after drying 5 μm) were sequentially laminated to form the surface protective layer 4, thereby obtaining the decorative sheet of Example 1 with a total thickness of 160 μm.

(Upper layer 4a)
The thermosetting composition for the upper layer 4a was prepared by blending the following polymer solution A with the following curing agent, ultraviolet absorber, and light stabilizer.

Polymer solution A
In a four-neck flask equipped with a stirrer, a nitrogen inlet tube, and a reflux condenser, 80 g of methyl methacrylate and 20 g of 2-hydroxyethyl methacrylate were introduced, 100 g of ethyl acetate was added to dissolve, and the mixture was stirred in a nitrogen atmosphere on an oil bath. Polymerization was initiated by adding 0.2 g of α,α'-azobisisobutyronitrile to the mixture, and the mixture was heated and stirred for 5 hours on a 60°C oil bath to obtain a colorless, viscous polymer solution A containing polyol.
Blend (amount of polymer solution A): 100 parts by weight

Hardener Product name: Duranate 24A-100 (manufactured by Asahi Kasei Corporation)
Formulation: 10 parts by weight Lubricant Product name: CERAFLOUR 991 (BYK Japan Co., Ltd.)
Blend: 0.5 parts by weight UV absorber Product name: Tinuvin 400 (manufactured by BASF)
Blended: 5.0 parts by weight Light stabilizer Product name: Tinuvin 123 (manufactured by BASF)
Blend: 2.0 parts by weight Dilution solvent name: Ethyl acetate Blend: 50 parts by weight

(Lower layer 4b)
The thermosetting composition for the lower layer 4b was prepared by blending the above polymer solution A with the following curing agent, lubricant, gloss regulator, anti-wear agent, UV absorber, and light stabilizer.

Polymer solution A
Mixture (amount of polymer solution A): 100 parts by weight Hardener name: Duranate 24A-100 (manufactured by Asahi Kasei Corporation)
Formulation: 5 parts by weight Gloss adjuster Product name: Sunsphere H-52 (AGC Si-Tech Co., Ltd.)
Properties: Spherical, average particle size 5μm, oil absorption 300mL/100g
Formulation: 10 parts by weight Anti-wear agent Product name: Sunsphere NP-100 (AGC Si-Tech Co., Ltd.)
Properties: Spherical, average particle size 10μm
Blend: 10 parts by weight UV absorber Product name: Tinuvin 400 (manufactured by BASF)
Blended: 5.0 parts by weight Light stabilizer Product name: Tinuvin 123 (manufactured by BASF)
Blend: 2.0 parts by weight Dilution solvent name: Ethyl acetate Blend: 50 parts by weight

Example 2
A decorative sheet of Example 2 was obtained in the same manner as in Example 1, except that the thickness of the core layer 2a in Example 1 was 30 μm and the thickness of the skin layer 2b was 5 μm.

Example 3
A decorative sheet of Example 3 was obtained in the same manner as in Example 1, except that the thickness of the core layer 2a in Example 1 was 170 μm and the thickness of the skin layer 2b was 10 μm.

Example 4
A decorative sheet of Example 4 was obtained in the same manner as in Example 1, except that the gloss regulator in Example 1 was replaced with the following.
・Gloss adjuster Product name: Sunsphere H-32 (AGC Si-Tech Co., Ltd.)
Properties: Spherical, average particle size 3μm, oil absorption 300mL/100g

Example 5
A decorative sheet of Example 5 was obtained in the same manner as in Example 1, except that the gloss regulator in Example 1 was replaced with the following.
・Gloss adjuster Product name: Sunsphere H-122 (AGC Si-Tech Co., Ltd.)
Properties: Spherical, average particle size 12μm, oil absorption 300mL/100g

Example 6
A decorative sheet of Example 6 was obtained in the same manner as in Example 1, except that the gloss regulator in Example 1 was replaced with the following:
・Gloss adjuster Product name: Sunsphere H-201 (AGC Si-Tech Co., Ltd.)
Properties: Spherical, average particle size 20μm, oil absorption 150mL/100g

Example 7
A decorative sheet of Example 7 was obtained in the same manner as in Example 1, except that the anti-wear agent in Example 1 was replaced with the following.
・Wear-resistant agent Product name: Sunsphere NP-200 (AGC Si-Tech Co., Ltd.)
Properties: Spherical, average particle size 20μm

Example 8
A decorative sheet of Example 8 was obtained in the same manner as in Example 1, except that polymer solution A in Example 1 was replaced with polymer solution B shown below and the curing agent was replaced with the following.
Polymer solution B
Into a four-neck flask equipped with a stirrer, a nitrogen inlet tube, and a reflux condenser, 50 g of methyl methacrylate, 10 g of 2-hydroxyethyl methacrylate, and 40 g of butyl acrylate were introduced, and 100 g of ethyl acetate was added to dissolve the mixture, followed by stirring in a nitrogen atmosphere on an oil bath. Polymerization was initiated by adding 0.2 g of α,α'-azobisisobutyronitrile to the mixture, and heating and stirring were continued for 5 hours on a 60°C oil bath to obtain a colorless, viscous polymer solution B containing polyol.
・Hardening agent Product name: Takenate D-110 (manufactured by Mitsui Chemicals)

<Example 9>
A decorative sheet of Example 9 was obtained in the same manner as in Example 1, except that the blending amount of the lubricant in Example 1 was changed to 0.4 parts by mass.

Example 10
A decorative sheet of Example 10 was obtained in the same manner as in Example 1, except that the amount of lubricant used in Example 1 was changed to 6 parts by mass.

Example 11
A decorative sheet of Example 11 was obtained in the same manner as in Example 1, except that the thickness of the core layer 2a in Example 1 was 75 μm and the thickness of the skin layer 2b was 30 μm.

Example 12
A decorative sheet of Example 12 was obtained in the same manner as in Example 1, except that the thickness of the core layer 2a in Example 1 was 165 μm and the thickness of the skin layer 2b was 3 μm.

<Example 13>
The decorative sheet of Example 13 was obtained in the same manner as Example 8, except that the thickness of the core layer 2a of Example 8 was 22 μm, the thickness of the skin layer 2b was 9 μm, the amount of nucleating agent vesicles added to the skin layer 2b as a nucleating agent was 0.04 parts by mass, the gloss adjuster and wear-resistant agent were replaced as follows, and the amount of lubricant was replaced by 0.4 parts by mass.
・Gloss adjuster Product name: Sunsphere H-201 (AGC Si-Tech Co., Ltd.)
Properties: Spherical, average particle size 20μm, oil absorption 150mL/100g
・Wear-resistant agent Product name: Sunsphere NP-200 (AGC Si-Tech Co., Ltd.)
Properties: Spherical, average particle size 20μm

<Example 14>
The decorative sheet of Example 14 was obtained in the same manner as Example 13, except that the thickness of the core layer 2a of Example 13 was 180 μm, the thickness of the skin layer 2b was 3.5 μm, the amount of nucleating agent vesicle added to the skin layer 2b was 0.6 parts by mass as a nucleating agent, and the amount of lubricant was replaced with 6 parts by mass.

<Comparative Example 1>
A decorative sheet of Comparative Example 1 was obtained in the same manner as in Example 1, except that the gloss regulator in Example 1 was replaced with the following.
Gloss adjuster Product name: Silica 250N (manufactured by Fuji Silysia Chemical Ltd.)
Properties: Amorphous, average particle size 5μm, oil absorption 330mL/100g

<Comparative Example 2>
A decorative sheet of Comparative Example 2 was obtained in the same manner as in Example 1, except that the anti-wear agent added in Example 1 was removed.

<Comparative Example 3>
A decorative sheet of Comparative Example 3 was obtained in the same manner as in Example 1, except that the nucleating agent vesicles added to the skin layer 2b of Example 1 were changed to 0.04 parts by mass as the nucleating agent.

<Comparative Example 4>
A decorative sheet of Comparative Example 4 was obtained in the same manner as in Example 1, except that the nucleating agent vesicles added to the skin layer 2b of Example 1 were changed to 0.6 parts by mass as the nucleating agent.

<Comparative Example 5>
A decorative sheet of Comparative Example 5 was obtained in the same manner as in Example 1, except that the thickness of the core layer 2a in Example 1 was 30 μm and the thickness of the skin layer 2b was 3 μm.

<Comparative Example 6>
A decorative sheet of Comparative Example 6 was obtained in the same manner as in Example 1, except that the thickness of the core layer 2a in Example 1 was 200 μm and the thickness of the skin layer 2b was 10 μm.

<Comparative Example 7>
A decorative sheet of Comparative Example 7 was obtained in the same manner as in Example 1, except that an untreated nucleating agent was used instead of the nucleating agent vesicles of Example 1.

(evaluation)
For the decorative sheets of Examples 1 to 14 and Comparative Examples 1 to 7 obtained by the above-mentioned methods, the Martens hardness was measured and evaluations were made on the scratch resistance, bending workability, and hiding power.
In this embodiment, the evaluations of "◎", "◯" and "△" were deemed acceptable since there was no problem in using the product.

<Martens hardness measurement method>
The method for measuring the Martens hardness will be described. The Martens hardness of each decorative sheet was measured using a Martens hardness measuring device (Fisherscope HM2000; manufactured by Fisher Instruments Co., Ltd.) conforming to ISO14577. Since the measurement was performed from the cross section, the decorative sheet 1 of the sample was embedded in a resin such as a cold-curing epoxy resin or a UV-curable resin and sufficiently cured, and then cut so that the cross section of the decorative sheet 1 appeared, and mechanical polishing was performed to obtain a measurement surface. The specific measurement method was to press an indenter into the measurement surface of each sample, and calculate the Martens hardness from the indentation depth and the load. The measurement was performed under the measurement conditions of a test force of 10 mN, a test force load time of 10 seconds, and a test force holding time of 5 seconds. The calculated Martens hardness of each sample is as shown in Table 1.

<Scratch resistance>
After attaching the sample to wood substrate B using a urethane adhesive, a Hoffman scratch test was performed using a Hoffman scratch hardness tester (manufactured by BYK-Gardner). The detailed evaluation methods for each evaluation test are described below.

Evaluation of deep scratches For scratch resistance, especially for deep scratches, a Hoffman scratch test was carried out with a load of 300 g to 2000 g in increments of 100 g.
The evaluation criteria were as follows.
◎: No scratches at 1900g to 2000g 〇: No scratches at 1500g to 1800g △: No scratches at 1000g to 1400g ×: Scratches at 900g or less

Evaluation of shallow scratches (change in gloss) For scratch resistance, particularly for shallow scratches, a Hoffman scratch test was carried out 10 times in succession with a load of 500 g so as to form a thick line. Thereafter, the glossiness was measured before and after the Hoffman scratch test, and the amount of change in gloss was calculated as follows.
Change in gloss=(glossiness after test−glossiness before test)/glossiness before test. The glossiness was measured at 85° using a Rhopoint IQ (manufactured by Konica Minolta).
The evaluation criteria were as follows.
◎: The gloss change is less than 5%. ◯: The gloss change is less than 10%. △: The gloss change is 10% or more but less than 20%. ×: The gloss change is 20% or more.

<Bending workability>
After attaching it to the wooden board B with a urethane adhesive, a V-shaped groove was made on the other side of the decorative sheet 1 up to the boundary where the wooden board B and the decorative sheet 1 were attached, so as not to scratch the opposite side of the decorative sheet 1. Next, the wooden board B was bent 90 degrees along the V-shaped groove so that the surface of the decorative sheet 1 formed a mountain fold, and the bent part of the surface of the decorative sheet 1 was observed with an optical microscope to see if there was any whitening or cracking, and the state of bending workability was evaluated.
The evaluation criteria were as follows.
◎: No whitening or cracks are observed. 〇: Slight whitening is observed in some areas. △: Whitening is observed in some areas. ×: Whitening is observed over the entire surface or cracks are observed in some areas.

<Concealment>
The evaluation of the hiding power was made by using a spectrophotometer (530JP/LP) manufactured by X-Rite, and judging the color difference measured on a hiding test paper (byco-chart high brightness 2A) manufactured by BYK-Gardner, Inc. with a white background and a black background. The smaller the color difference value, the better the hiding power.
The evaluation criteria were as follows.
⊚: hiding power is less than 0.3; ◯: hiding power is 0.3 or more and less than 0.5; Δ: hiding power is 0.5 or more and less than 1.0; ×: hiding power is 1.0 or more

The evaluation results are shown in Table 1.

As shown in Table 1, the decorative sheets of Examples 1 to 14 provide a decorative sheet that combines scratch resistance, bending workability, and hiding power, and in particular, reduces gloss changes caused by deep, gouged scratches and shallow scratches.

Reference Signs List 1 Decorative sheet 2 Base layer 2a Core layer 2b Skin layer 3 Design layer 4 Surface protective layer 4a Upper layer 4b Lower layer 5 Concealing layer 6 Primer layer 10a Gloss regulator 10b Abrasion resistant agent 11 Decorative material B Substrate

Claims (14)

A substrate layer and a surface protective layer formed on the substrate layer,
the base layer has a core layer containing an inorganic pigment and a polypropylene resin, and skin layers containing polypropylene resin formed on both sides of the core layer,
The skin layer is formed by adding a nucleating agent vesicle having a single-layer outer membrane and a nano-sized nucleating agent encapsulated in the vesicle to the polypropylene resin, and the skin layer has a Martens hardness in the range of 68 N/mm2 or ^more and 120 N/mm2 or ^less ;
The thickness of the base layer is in the range of 40 μm or more and 200 μm or less,
the surface protective layer has a lower layer formed on the base layer side and an upper layer formed on the lower layer,
A decorative sheet comprising a spherical gloss control agent and a spherical abrasion resistant agent in the lower layer. the gloss control agent contained in the lower layer contains silica, and the average particle size of the silica is within a range of 2 μm or more and 15 μm or less;
2. The decorative sheet according to claim 1, wherein the anti-wear agent contained in the lower layer contains at least one of silica and glass, and the average particle size thereof is within a range of 2 μm to 15 μm. The main material of the resin component constituting the surface protective layer is a thermosetting resin,
3. The decorative sheet according to claim 1, wherein the thermosetting resin is composed of an acrylic polyol and an isocyanate curing agent, and has a Martens hardness in the range of 140 N/mm2 or ^more and 200 N/ ^mm2 or less. The decorative sheet according to any one of claims 1 to 3, characterized in that the upper layer contains a lubricant in a range of 0.5 parts by mass to 5 parts by mass per 100 parts by mass of the resin that is the main component of the upper layer. The decorative sheet according to any one of claims 1 to 4, characterized in that the thickness of the core layer is in the range of 3 to 50 times the thickness of one of the skin layers. The decorative sheet according to any one of claims 1 to 5, characterized in that the amount of the nucleating agent vesicle added is in the range of 0.05 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. The decorative sheet according to any one of claims 1 to 6, characterized in that the nucleating agent vesicle is a nucleating agent liposome having an outer membrane made of phospholipids. The decorative sheet according to any one of claims 1 to 7, characterized in that the nucleating agent vesicle is formed by encapsulating the nucleating agent in a vesicle having a monolayer membrane by supercritical reverse phase evaporation. The decorative sheet according to any one of claims 1 to 8, characterized in that a pattern layer is laminated between the substrate layer and the surface protective layer. 10. The decorative sheet according to claim 1, wherein the skin layer has a Martens hardness of 80 N/ ^mm2 or more. The decorative sheet according to any one of claims 1 to 10, characterized in that the skin layers formed on both sides of the core layer have different Martens hardnesses. The decorative sheet according to any one of claims 1 to 9, characterized in that the Martens hardness of the skin layer located on the surface protective layer side is in the range of 1.1 to 3 times, or in the range of 0.5 to 0.9 times, the Martens hardness of the skin layer located on the opposite side to the surface protective layer side. The decorative sheet according to any one of claims 1 to 10, characterized in that the Martens hardness of the skin layer is different from the Martens hardness of the core layer. The decorative sheet according to any one of claims 1 to 10, characterized in that the Martens hardness of the skin layer is in the range of 1.1 to 3 times the Martens hardness of the core layer, or in the range of 0.5 to 0.9 times the Martens hardness of the core layer.

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