Decorative sheet and decorative laminate

Abstract

To provide a decorative sheet and a decorative laminate which are excellent in scratch resistance and also excellent in impact resistance and are made of a polyolefin-based resin.SOLUTION: A decorative sheet 10 includes: a colored resin layer 11 containing a polyolefin-based resin; a pattern layer 12 provided on the colored resin layer 11; a transparent resin layer 13 provided on the pattern layer 12 and containing a crystalline polypropylene resin; and a surface protective layer 14 which is provided on the transparent resin layer 13 and at least the outermost surface of which contains an ultraviolet-curable resin. The transparent resin layer 13 is formed with a nano-sized nucleating agent contained in an amount of 0.01 pt.mass or more and 0.02 pt.mass or less based on the crystalline polypropylene resin.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a decorative sheet and decorative board for use in the exterior and interior decoration of buildings, and is particularly suitable for use as a flooring material. [Background technology]

[0002] Polyvinyl chloride, which is widely used in decorative sheets, generates toxic gases and the like when incinerated, so in recent years polyolefin-based resins have been widely used in decorative sheets. Decorative sheets using polyolefin-based resins use general polypropylene sheets or soft polypropylene sheets, and therefore have inferior surface scratch resistance compared to decorative sheets made of polyvinyl chloride. Therefore, the present inventors have conducted extensive research and developed decorative sheets and decorative panels made of polyolefin-based resins with excellent surface scratch resistance (see Patent Documents 1 to 4 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6636776 [Patent Document 2] Patent No. 6861941 [Patent Document 3] Patent No. 6933830 [Patent Document 4] Patent No. 6933831 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a decorative sheet made of polyolefin resin with excellent scratch resistance as described above is used as a flooring material, when an object is dropped on it, depending on the hardness of the object, impact cracks may occur on the surface of the decorative sheet.

[0005] In view of the above, an object of the present invention is to provide a decorative sheet and decorative board made of a polyolefin resin that is excellent in both abrasion resistance and impact resistance. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the decorative sheet of the present invention comprises a colored resin layer containing a polyolefin resin, a pattern layer provided on the colored resin layer, a transparent resin layer provided on the pattern layer and containing a crystalline polypropylene resin, and a surface protection layer provided on the transparent resin layer, at least the outermost surface of which contains an ultraviolet-curable resin, wherein the transparent resin layer is formed containing 0.01 parts by mass or more and 0.02 parts by mass or less of a nano-sized nucleating agent per 100 parts by mass of the crystalline polypropylene resin.

[0007] In addition, the decorative sheet of the present invention is preferably such that, in the above-mentioned decorative sheet, the surface protection layer has two layers: a topcoat layer located on the surface side and containing an ultraviolet-curable resin, and an undercoat layer located on the transparent resin layer side and containing a two-component curable resin.

[0008] Moreover, in the decorative sheet according to the present invention, in the decorative sheet described above, the crystalline polypropylene resin is preferably a highly crystalline polypropylene resin having an isotactic pentad fraction (mmmm fraction) of 95% or more.

[0009] In addition, the decorative sheet according to the present invention is preferably the decorative sheet described above, in which the nucleating agent is encapsulated in vesicles.

[0010] In addition, the decorative sheet of the present invention is preferably the decorative sheet described above, wherein the vesicle has an outer membrane containing at least one of a polymeric surfactant, a fatty acid metal salt, a silane coupling agent, a titanate coupling agent, a silicone, a wax, and a modified resin.

[0011] Furthermore, in the decorative sheet according to the present invention, in the above-mentioned decorative sheet, it is preferable that the vesicle has a single-layer outer membrane containing phospholipids.

[0012] On the other hand, in order to solve the above-mentioned problems, the decorative board of the present invention is characterized in that it comprises the decorative sheet of the present invention described above, a substrate provided on the back side of the decorative sheet, and an adhesive layer provided between the decorative sheet and the substrate. Effect of the Invention

[0013] In the decorative sheet and decorative plate of the present invention, the transparent resin layer is formed by incorporating a nano-sized nucleating agent into the crystalline polypropylene resin, so that not only can it exhibit excellent scratch resistance, but also, since the content of the nucleating agent is 0.01 part by mass or more and 0.02 part by mass or less, it can exhibit excellent impact resistance. [Brief description of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing a schematic structure of a main embodiment of a decorative sheet according to the present invention. [Diagram 2] 1 is a cross-sectional view showing a schematic structure of a main embodiment of a decorative board according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The embodiments of the decorative sheet and decorative board according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the following embodiments described with reference to the drawings, and various technical matters described in each embodiment can be appropriately replaced or combined as necessary.

[0016] [Decorative sheet / Main embodiment] A main embodiment of the decorative sheet according to the present invention will be described with reference to FIG.

[0017] <Overall structure of decorative sheet> As shown in Fig. 1, a design layer 12 is provided on a colored resin layer 11 made of a polyolefin resin. A transparent resin layer 13 containing a crystalline polypropylene resin is provided on the design layer 12. A surface protective layer 14 is provided on the transparent resin layer 13, the surface protective layer 14 having two layers: an overcoat layer 14b located on the surface side and containing an ultraviolet (UV) curable resin, and an undercoat layer 14a located on the transparent resin layer 13 side and containing a two-component curable resin.

[0018] The decorative sheet 10 according to this embodiment preferably has a thickness of 80 μm or more and 250 μm or less. In Fig. 1, 10a denotes an embossed portion. Next, each layer of the decorative sheet 10 will be described in more detail.

[0019] <Colored resin layer 11> The colored resin layer 11 is a polyolefin resin containing inorganic filler so as to have concealing properties, and in consideration of workability, cost, etc., it is preferable that the thickness is 30 μm or more and 150 μm or less.

[0020] Examples of polyolefin resins include polypropylene, polyethylene, polybutene, and the like, as well as α-olefins (e.g., 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, 4-ethyl ... Examples of such copolymers include those obtained by homopolymerizing or copolymerizing two or more types of α-olefins (e.g., 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) and those obtained by copolymerizing ethylene or α-olefins with other monomers.

[0021] Examples of inorganic fillers include opaque pigments, calcium carbonate, talc, titanium oxide, iron oxide, etc. Among them, calcium carbonate is very suitable because it is possible to easily control the particle size by the manufacturing method, and adjust the compatibility with polyolefin resins by surface treatment, and also because the material cost is inexpensive. In addition, in order to further improve the hiding power, it is possible to contain metals such as gold, silver, copper, and aluminum. Generally, flake-shaped aluminum is often contained.

[0022] The colored resin layer 11 is preferably made of a uniaxially stretched sheet or a biaxially stretched sheet. When the colored resin layer 11 is a uniaxially stretched sheet or a biaxially stretched sheet, the mechanical strength of the colored resin layer 11 can be further improved. In addition, by using a uniaxially stretched sheet or a biaxially stretched sheet, the surface smoothness of the colored resin layer 11 can be further improved, and the ink receptivity can be further improved when printing the design layer 12, resulting in a colored resin layer 11 with excellent printability.

[0023] The colored resin layer 11 is preferably a mixture of 50 parts by mass or more and 900 parts by mass or less of inorganic filler with respect to 100 parts by mass of polyolefin resin. In this embodiment, the content of the inorganic filler in the colored resin layer 11 is specified by the mixing ratio when preparing the resin composition constituting the colored resin layer 11. This is for the following reason.

[0024] When the colored resin layer 11 formed from the resin composition mixed in the above ratio is subjected to post-processing such as bending, the inorganic filler moves due to deformation caused by the processing. Since the colored resin layer 11 is deformed more in the vicinity of the surface than in the interior, the inorganic filler does not move uniformly throughout the colored resin layer 11, but moves more in the vicinity of the surface than in the interior, resulting in a density difference between the interior and the vicinity of the surface. Therefore, it is practically difficult to specify the content of the inorganic filler per unit volume in the post-processed colored resin layer 11 in general.

[0025] In addition, when measuring the content of the inorganic filler in the colored resin layer 11, the colored resin layer 11 must first be separated into inorganic material and organic material, and the inorganic filler in the separated inorganic material must be identified, and then the content of the inorganic filler must be calculated. This is because many pretreatment steps must be performed, which requires a lot of time and effort and is not practical.

[0026] <Pattern layer 12> The design layer 12 is printed with ink so as to provide a design on the colored resin layer 11. The ink is a binder containing a coloring agent such as a pigment or dye, an extender pigment, a solvent, and various additives.

[0027] Examples of binders include nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, polyester, etc., either alone or modified. The binder can be of any of the following types: water-based, solvent-based, and emulsion types, and can be of either a one-liquid type or a two-liquid type using a hardener, as required. Furthermore, types that are hardened by irradiation with ultraviolet rays, electron beams, etc. can also be used.

[0028] Examples of the pigment include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica.

[0029] Generally, inks that use a urethane binder and are cured with isocyanate are the most widely used. In addition to printing with ink, it is also possible to apply designs such as patterns by vapor deposition or sputtering of various metals.

[0030] <Transparent resin layer 13> The transparent resin layer 13 is formed by containing 0.01 to 0.02 parts by mass of a nano-sized nucleating agent relative to 100 parts by mass of crystalline polypropylene resin. In consideration of design, post-processing, cost, etc., the transparent resin layer 13 preferably has a thickness of 20 μm to 250 μm, more preferably 30 μm to 150 μm.

[0031] The crystalline polypropylene resin can be designed by appropriately selecting from isotactic polypropylene, syndiotactic polypropylene, random polypropylene, block polypropylene, and mixtures thereof, which have different pentad fractions. It is most preferable that the crystalline polypropylene resin is a homopolymer of propylene, i.e., a highly crystalline homopolymer, with an isotactic pentad fraction (mmmm fraction) of 95% or more, more preferably 96% or more.

[0032] Here, we will explain the isotactic pentad fraction (mmmm fraction). The mmmm fraction is a fraction that uses carbon C (nuclide) with a mass number of 13. 13 It is determined from the numerical value (electromagnetic wave absorption rate) obtained by resonating a resin material at a specified resonance frequency using C-nuclear magnetic resonance (NMR) measurement, and specifies the atomic arrangement, electronic structure, and molecular microstructure of the resin material.

[0033] In the case of polypropylene resin, the mmmm fraction is: 13 This is the ratio of five propylene units arranged in a row determined by C-NMR measurement, and can be used as a measure of crystallinity and stereoregularity. The higher the value of this mmmm fraction, the higher the crystallinity and the higher the scratch resistance.

[0034] The transparent resin layer 13 may contain 90% by mass or more of crystalline polypropylene resin and 10% by mass or less of other polyolefin resins. The other polyolefin resins may be appropriately selected depending on the purpose of blending, as long as they do not significantly affect the physical properties of the crystalline polypropylene resin. In particular, it is highly preferable that the other polyolefin resins have excellent compatibility with the crystalline polypropylene resin, considering post-processing.

[0035] Nucleating agents are mixed into resins to promote the formation of crystal nuclei in the resin or to make the nuclei themselves crystal nuclei when the resin crystallizes. There are two types of nucleating agents: molten type, which melts in the resin when mixed into it and then precipitates again to form crystal nuclei, and non-molten type, which does not melt in the resin and remains as it is to become crystal nuclei.

[0036] Examples of nucleating agents for polypropylene resin include metal phosphates, metal benzoates, metal pimelates, metal rosins, benzylidene sorbitol, quinacridone, cyanine blue, and talc. In order to maximize the effect of nano-processing, it is preferable to use metal phosphates, metal benzoates, metal pimelates, and metal rosins, which are non-melting and can be expected to have good transparency. In addition, when transparency can be achieved by nano-processing, colored quinacridones, cyanine blue, and talc can be used. It is also possible to appropriately mix melting benzylidene sorbitol with a non-melting nucleating agent.

[0037] The nucleating agent is made into nano-sized particles by a nano-sizing technique (nano-processing). More specifically, the nucleating agent preferably has an average particle size of 375 nm or less. Examples of nano-processing include a solid-phase method in which the nucleating agent is mainly mechanically pulverized to make nano-sized particles, a liquid-phase method in which nano-sized particles are synthesized or crystallized in a solution in which the nucleating agent is dissolved, and a gas-phase method in which nano-sized particles are synthesized or crystallized from the gas or vapor of the nucleating agent.

[0038] Specific means for carrying out these methods are listed below. Examples of solid phase methods include a ball mill, a bead mill, a rod mill, a colloid mill, a conical mill, a disk mill, a hammer mill, and a jet mill. Examples of liquid phase methods include a crystallization method, a coprecipitation method, a sol-gel method, a liquid phase reduction method, and a hydrothermal synthesis method. Examples of gas phase methods include an electric furnace method, a chemical flame method, a laser method, and a thermal plasma method.

[0039] A more specific method of nano-processing is described below. As the solid phase method, for example, a mixture of 100g of isopropyl alcohol and 50g of sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphonate is treated for 60 minutes using stabilized zirconia beads with a diameter of 30 μm. This allows the production of nano-sized nucleating agent particles with an average particle size of about 100 to 150 nm.

[0040] In the liquid phase method (crystallization method), for example, 50 g of sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphonate is dissolved in a mixed solvent of 96 g of xylene, 72 g of isopropyl alcohol, and 24 g of water, and the solution is brought into contact with a poor solvent such as ethanol in a microreactor. This allows the nucleating agent to precipitate nano-sized particles with an average particle size of 1 to 150 nm.

[0041] The nucleating agent is preferably encapsulated in a vesicle (nucleating agent-encapsulated vesicle). The average particle size of the nano-sized nucleating agent-encapsulated vesicle is preferably 1 / 2 or less of the wavelength of visible light. Specifically, since the wavelength range of visible light is 400 to 750 nm, the average particle size is preferably 375 nm or less.

[0042] The nucleating agent-containing vesicle has a liquid phase inside a vesicle-like capsule (vesicle) having a membrane structure (outer membrane) closed in a spherical shell shape, and contains the nucleating agent in this liquid phase. It is preferable that the outer membrane of the nucleating agent-containing vesicle is made of a dispersant. Such nucleating agent-containing vesicles are difficult to aggregate because the outer membranes repel each other, and can exhibit extremely high dispersibility. Therefore, the nucleating agent-containing vesicle is easily dispersed uniformly in the resin material. Examples of the dispersant include polymeric surfactants, fatty acid metal salts, silane coupling agents, titanate coupling agents, silicones, waxes, modified resins, and the like.

[0043] Examples of polymer surfactants include aliphatic polyvalent polycarboxylic acids, polycarboxylate alkylamines, polyacrylic acids, polymethacrylic acids, polyoxyethylene alkyl ethers, sorbitan fatty acid esters, etc. Examples of fatty acid metal salts include those in which stearic acid, lauric acid, 12-hydroxystearic acid, montanic acid, behenic acid, ricinoleic acid, myristic acid, etc. are combined with lithium, sodium, potassium, magnesium, calcium, barium, zinc, aluminum, etc.

[0044] Examples of the silane coupling agent include 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0045] Examples of titanate coupling agents include tetrakis[2,2-bis(allyloxymethyl)butoxy]titanium(IV), di-i-propoxytitanium diisostearate, (2-n-butoxycarbonylbenzoyloxy)tributoxytitanium, isopropyl titanium triisostearate, di-n-butoxy bis(triethanolaminato)titanium, tetrakis(2-ethylhexyloxy)titanium, and di-i-propoxy bis(acetylacetonato)titanium.

[0046] Examples of silicones include dimethyl silicone oil, methyl phenyl silicone oil, methyl hydrogen silicone oil, cyclic dimethyl silicone oil, alkyl modified silicone oil, long chain alkyl modified silicone oil, higher fatty acid modified silicone oil, etc., and examples of olefin polymers or polyolefins thermally decomposed and further oxidized or modified with maleic acid, sulfonic acid, carboxylic acid, rosin acid, etc. Examples of modified resins include polyolefin resins modified with maleic acid, sulfonic acid, carboxylic acid, rosin acid, etc.

[0047] Examples of vesicle formation techniques for obtaining nucleating agent-encapsulating vesicles include the Bangham method, extrusion method, hydration method, surfactant dialysis method, reverse phase evaporation method, freeze-thaw method, supercritical reverse phase evaporation method, etc. Such vesicle formation treatments will be briefly described below.

[0048] In the Bangham method, chloroform or a mixed solvent of chloroform and methanol is placed in a container such as a flask, and then phospholipids are added and dissolved, and the solvent is removed using an evaporator to form a thin film made of lipids. Then, a dispersion of a nucleating agent is added, and the mixture is stirred with a vortex mixer to hydrate and disperse, thereby obtaining vesicles containing the nucleating agent.

[0049] The extrusion method is a method of obtaining nucleating agent vesicles by preparing a solution of phospholipids that will become a thin film and passing the solution through a filter instead of the mixer used as an external perturbation in the Bangham method. The hydration method is a preparation method almost the same as the Bangham method, but it is possible to obtain nucleating agent-encapsulated vesicles by dispersing the solution by gentle stirring without using a mixer.

[0050] In the reverse phase evaporation method, phospholipids are dissolved in diethyl ether or chloroform, a solution containing a nucleating agent is added to form a W / O emulsion, the organic solvent is removed by reducing the pressure, and then water is added to obtain vesicles containing the nucleating agent. The freeze-thaw method uses cooling and heating as an external perturbation, and vesicles containing the nucleating agent can be obtained by repeating this cooling and heating.

[0051] The nucleating agent-encapsulating vesicle is preferably one having a single-layer outer membrane, since the diameter size can be made smaller. Examples of a method for forming a single-layer outer membrane include supercritical reverse phase evaporation. The supercritical reverse phase evaporation method is a method for producing a vesicle encapsulating a nucleating agent using carbon dioxide in a supercritical state or a temperature or pressure state above the critical point. The supercritical state refers to a supercritical state above the critical temperature (30.98°C) and the critical pressure (7.3773±0.0030MPa). The temperature or pressure state above the critical point refers to a state in which only the temperature or pressure exceeds the critical state.

[0052] A specific processing method using the supercritical reverse phase evaporation method will be described. An aqueous phase is injected into a mixed fluid of supercritical carbon dioxide, phospholipids, and a nucleating agent, and the mixture is stirred to generate an emulsion of supercritical carbon dioxide and an aqueous phase. When the pressure is reduced, the carbon dioxide expands and evaporates, causing a phase inversion, and nanocapsules are generated in which the phospholipids cover the surface of the nucleating agent particles with a single layer membrane.

[0053] By applying such a supercritical reverse phase evaporation method, unlike the conventional method in which the surface of the nucleating agent particles is covered with multiple membranes, it is possible to easily produce nanocapsules in which the surface of the nucleating agent particles is covered with a single layer of membrane, and therefore it is possible to easily prepare nanocapsules with a smaller diameter. In addition, when the surface of the nucleating agent particles is covered with multiple membranes, this can be easily done by injecting supercritical carbon dioxide into a mixed fluid of phospholipids, nucleating agent, and an aqueous phase and stirring the mixture.

[0054] Examples of phospholipids include glycerophospholipids such as phosphatidylcholine, phosphatidiethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, cardiopin, yolk egg lecithin, hydrogenated yolk egg lecithin, soybean lecithin, and hydrogenated soybean lecithin, and sphingophospholipids such as sphingomyelin, ceramide phosphorylethanolamine, and ceramide phosphorylglycerol. Such nucleating agent-encapsulating vesicles having an outer membrane made of phospholipids can achieve excellent compatibility with resin materials.

[0055] The number and surface area of ​​nucleating agents per unit volume in a resin increases inversely proportional to the cube of the particle diameter, so if the particle size is extremely small (nanometer size), the distance between each particle becomes very close. Therefore, when crystal growth occurs from the surface of one particle in the resin, the end of the growing crystal immediately comes into contact with the end of the crystal growing from the surface of another particle adjacent to that particle, and the ends of the crystals inhibit each other's growth, stopping the growth of each crystal. This allows the average diameter of spherulites in the crystalline part of the crystalline polypropylene resin to be extremely small.

[0056] In other words, by adding a nano-sized nucleating agent to the resin, it is possible to generate a larger number of finer crystal nuclei in the resin than with conventional nucleating agents. This shortens the distance between crystal nuclei in the crystal part, suppresses the growth of individual crystals, and makes it possible to make the average diameter of the spherulites extremely small.

[0057] In this case, if the nano-sized nucleating agent is contained in an amount of 0.01 part by mass or more and 0.02 part by mass or less per 100 parts by mass of crystalline polypropylene resin, not only can excellent scratch resistance be exhibited, but also excellent impact resistance can be exhibited.

[0058] In addition, by making the nano-sized nucleating agent into a vesicle state, i.e., a nucleating agent-encapsulated vesicle, it is possible to significantly suppress aggregation of the nucleating agent and significantly improve dispersibility. In addition, in the resin, the outer membrane of the nucleating agent-encapsulated vesicle partially collapses to expose the nucleating agent, thereby forming spherulites with the nucleating agent particles as crystal nuclei during the resin crystallization process.

[0059] Here, when the nucleating agent-encapsulating vesicles have an extremely small size obtained by supercritical reverse phase evaporation, the average particle size of the spherulites in the crystalline portion of the crystalline polypropylene resin can be made extremely small, and the crystallinity of the crystalline portion can be dramatically improved.

[0060] The transparent resin layer 13 may contain various additives, such as a heat stabilizer, a flame retardant, an ultraviolet absorber, a light stabilizer, an antiblocking agent, a catalyst trap, a colorant, a light scattering agent, and a gloss adjuster, as necessary.

[0061] Examples of the heat stabilizer include phenol-based, sulfur-based, phosphorus-based, and hydrazine-based agents. Examples of the flame retardant include aluminum hydroxide and magnesium hydroxide. Examples of the ultraviolet absorber include benzotriazole-based, benzoate-based, benzophenone-based, and triazine-based agents. Examples of the light stabilizer include hindered amine-based agents.

[0062] In particular, the ultraviolet absorbing agent and the light stabilizer are appropriately combined and mixed depending on the purpose. Specifically, from the viewpoint of weather resistance, it is preferable that each of them is contained in the transparent resin layer 13 in the range of 0.1 mass % or more and 1.0 mass % or less.

[0063] <Surface protective layer 14> The surface protective layer 14 has two layers: an undercoat layer 14a made of a two-component curable resin provided on the transparent resin layer 13, and an overcoat layer 14b made of a UV-curable resin provided on the undercoat layer 14a. These curable resins can be in various forms such as water-based, emulsion, and solvent-based.

[0064] The two-component curing resin is preferably a urethane resin from the viewpoints of workability, cost, cohesive strength of the resin itself, etc. Examples of the urethane resin include those obtained by reacting an acrylic polyol with an isocyanate.

[0065] Examples of isocyanates include tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), bis(isocyanatomethyl)cyclohexane (HXDI), trimethylhexamethylene diisocyanate (TMDI), their derivatives such as adducts, biuret, and isocyanurate, and curing agents for various prepolymers. Among these, the application of a curing agent based on hexamethylene diisocyanate (HMDI) or isophorone diisocyanate (IPDI) having a linear molecular structure is preferable from the viewpoint of weather resistance.

[0066] Examples of UV-curable resins include polyester acrylates, epoxy acrylates, urethane acrylates, acrylic acrylates, etc. Among these, urethane acrylates and acrylic acrylates are preferred from the viewpoint of weather resistance (light resistance).

[0067] The surface protective layer 14 may contain an ultraviolet absorbing agent or a light stabilizer to further improve weather resistance. The surface protective layer 14 may also contain functional additives such as antibacterial agents and antifungal agents to achieve various functions. Furthermore, the surface protective layer 14 may contain alumina, silica, silicon nitride, silicon carbide, glass beads, etc. to adjust the gloss and further improve the abrasion resistance.

[0068] <Method of manufacturing the decorative sheet 10> A method for producing the decorative sheet 10 according to this embodiment will be described below. One or both sides of the colored resin layer 11 made of a polyolefin resin film containing an inorganic filler are subjected to activation treatment such as corona treatment, plasma treatment, electron beam treatment, ultraviolet treatment, dichromate treatment, etc. as necessary, and then ink is printed on the colored resin layer 11 (one side) by gravure printing, offset printing, screen printing, flexographic printing, electrostatic printing, ink jet printing, etc. to provide the design layer 12.

[0069] Then, a highly crystalline polypropylene resin containing a nano-sized nucleating agent is extruded from an extruder onto the pattern layer 12 while pressing an embossing plate having an uneven surface against the pattern layer 12 to form a transparent resin layer 13 having embossments 10a on its surface. Subsequently, an activation treatment such as a corona treatment is applied to the transparent resin layer 13, and then a two-component curing resin is applied onto the transparent resin layer 13 to form an undercoat layer 14a, and a UV-curing resin is further applied onto the undercoat layer 14a to form an overcoat layer 14b, thereby forming the surface protective layer 14. In this way, the decorative sheet 10 can be obtained.

[0070] <effect> In the decorative sheet 10 according to this embodiment, the transparent resin layer 13 is formed by incorporating a nano-sized nucleating agent into the crystalline polypropylene resin. Therefore, the average particle size of the spherulites in the crystalline portion of the crystalline polypropylene resin can be made very small, and excellent scratch resistance can be achieved. Here, since the content of the nano-sized nucleating agent relative to the crystalline polypropylene resin is 0.01 parts by mass or more and 0.02 parts by mass or less, excellent impact resistance can be further achieved (more specifically described below).

[0071] In addition, since the nucleating agent is encapsulated in the vesicle (nucleating agent-encapsulated vesicle), the outer membrane has dispersibility, making it difficult for the nucleating agent to aggregate and enabling extremely high dispersibility to be exhibited. Therefore, the nucleating agent-encapsulated vesicle is easily dispersed uniformly in the resin material, making it possible to make the crystallinity of the crystalline polypropylene uniform, and enabling it to exhibit better scratch resistance and post-processability.

[0072] In addition, by making the outer membrane a single layer, the vesicles encapsulating the nucleating agent can be made smaller, and the average particle size of the spherulites in the crystalline portion of the crystalline polypropylene resin can be made smaller, thereby achieving better scratch resistance.

[0073] [Decorative sheet / other embodiments] In the above embodiment, the embossment 10a is directly formed on the transparent resin layer 13 by pressing the crystalline polypropylene sheet extruded from the extruder while being heated with an embossing plate, but the present invention is not limited to this. As another embodiment, for example, the embossment 10a can be directly formed on the transparent resin layer 13 by pressing the crystalline polypropylene sheet extruded from the extruder while being heated with a cooling roll having an uneven surface while being cooled. In addition, the embossment 10a can be formed by laminating the surface protection layer 14 on the transparent resin layer 13 and then pressing the embossing plate while being heated. Furthermore, the design can be further improved by embedding ink in the embossment 10a.

[0074] In the above-described embodiment, the decorative sheet 10 is manufactured by sequentially laminating the layers using an extrusion lamination method, but the present invention is not limited to this. In other embodiments, the decorative sheet can be manufactured by, for example, laminating the layers together and thermocompression bonding them, or dry laminating them with an adhesive layer interposed therebetween.

[0075] In the above-mentioned embodiment, the decorative sheet 10 has two layers, an undercoat layer 14a containing a two-component curable resin and an overcoat layer 14b containing a UV-curable resin, and is provided with a surface protective layer 14 containing a UV-curable resin on the outermost surface, but the present invention is not limited to this. As another embodiment, for example, it is possible to omit the undercoat layer 14a and provide only the overcoat layer 14b, thereby providing a decorative sheet with a surface protective layer containing a UV-curable resin on the outermost surface.

[0076] [Decorative board / Main embodiment] A main embodiment of the decorative board according to the present invention will be described with reference to Fig. 2. However, for parts similar to those in the above-mentioned embodiment, the same reference numerals as those used in the description of the above-mentioned embodiment will be used, and descriptions that overlap with those in the above-mentioned embodiment will be omitted.

[0077] <Overall structure of decorative panel> 2, an undercoat layer 25 is provided on the back surface side (lower surface side in FIG. 2) of the colored resin layer 11. In this embodiment, the decorative sheet 20 is configured with such an undercoat layer 25.

[0078] An adhesive layer 102 is adhered to the back side (the bottom side in FIG. 2) of the base layer 25 of the decorative sheet 20. A substrate 101 is adhered to the adhesive layer 102. In other words, the decorative sheet 20 includes the substrate 101 provided on the back side (the bottom side in FIG. 2) of the decorative sheet 20, and the adhesive layer 102 provided between the decorative sheet 20 and the substrate 101. In this embodiment, the decorative sheet 20, the substrate 101, the adhesive layer 102, etc. constitute the decorative board 100.

[0079] <Base layer 25> The underlayer 25 is provided mainly for the purpose of improving adhesion, and also has functions such as stabilizing the surface after surface treatment, imparting tackiness, and preventing deterioration of the adhesive. From the viewpoint of ensuring adhesion, the underlayer 25 preferably has a thickness of 0.1 μm or more and 3 μm or less. The underlayer 25 is formed, for example, by applying a urethane resin by gravure printing or the like.

[0080] Considering that the base layer 25 is provided on the back surface of the decorative sheet 20 and rolled up into a web, it is preferable for the base layer 25 to contain an inorganic filler such as silica, alumina, magnesia, titanium oxide, barium sulfate, etc., thereby increasing adhesion to the adhesive layer 102 while avoiding blocking.

[0081] <Substrate 101> The substrate 101 is made of a hard material such as a wooden substrate such as wood plywood, a composite substrate made of a mixture of wood powder and plastic, or a resin substrate made of polyolefin such as polyethylene (PE) or polypropylene (PP) or polyvinyl chloride (PVC). Examples of wooden substrates include tropical wood plywood, particle board, medium density fiberboard (MDF), and ordinary plywood as specified by the Japanese Agricultural Standards. It is also possible to use a substrate made of an olefin resin containing wood powder. By providing the substrate 101, a decorative board 100 can be provided that is less susceptible to scratches.

[0082] <Adhesive layer 102> Adhesive layer 102 is provided on substrate 101 in order to attach decorative sheet 10 to substrate 101. When substrate 101 is made of, for example, a wood-based material, adhesive layer 102 is preferably a vinyl acetate emulsion type, a two-component curing urethane type, or the like.

[0083] <effect> The decorative panel 100 of this embodiment is not only able to exhibit excellent scratch resistance, like the decorative sheet 10 of the previously described embodiment, but also able to exhibit excellent impact resistance.

[0084] [Decorative board / other embodiments] In the above embodiment, the decorative board 100 is described in which the substrate 101 is attached to the base layer 25 of the decorative sheet 20 via the adhesive layer 102, but the present invention is not limited to this. In another embodiment, for example, when the colored resin layer 11 has sufficient adhesiveness, it is also possible to make a decorative board by attaching the substrate 101 to the colored resin layer 11 of the decorative sheet 10 via the adhesive layer 102. EXAMPLES

[0085] Examples of the decorative sheet and decorative board according to the present invention will be described specifically below, but the present invention is not limited to only the specific examples described below.

[0086] [Preparation of test specimens and comparison specimens] Test specimen 1 A pigment-containing colored polyethylene sheet (55 μm thick) manufactured by Riken Technos Corporation was used as a colored resin layer, and a polyurethane ink "Lamistar (registered trademark)" manufactured by Toyo Ink Co., Ltd. was gravure printed on the surface of this to form a pattern layer. Next, 0.01 parts by mass of a nucleating agent was mixed with high crystalline polypropylene resin "Prime Polypro (registered trademark)" manufactured by Prime Polymer Co., Ltd., and extrusion laminated onto the pattern layer using an extruder, while pressing an embossing plate having unevenness in the shape of wood grain vessels on its surface, thereby forming a transparent resin layer (80 μm thick) with embossing in the shape of wood grain vessels.

[0087] Next, the surface of the transparent resin layer was subjected to a corona treatment, and then 3 g / m of acrylic urethane two-component curing resin "UC Clear (product name)" manufactured by DIC Graphics Corporation was applied to the surface. 2 Then, a urethane acrylate UV-curable resin "UVT Clear (product name)" manufactured by DIC Graphics Corporation was applied at a rate of 5 g / m2 when dry. 2 After applying the coating in layers so that the surface is protected, the coating is cured by irradiating it with UV light from a metal halide lamp to form a topcoat layer.

[0088] In addition, a polyurethane ink "Lamistar (registered trademark)" manufactured by Toyo Ink Co., Ltd. was applied to the back side of the colored resin layer at a solid content of 1 g / m 2 The undercoat layer was provided by gravure printing so that the thickness of the undercoat layer was 100 μm. In this manner, a decorative sheet specimen 1A was produced.

[0089] Then, "BA-10L (product number)" and "BA-11B (product number)" of "Rikabond (registered trademark)", a two-part curing water-based emulsion adhesive manufactured by Japan Coating Resin Co., Ltd., are mixed in a mass ratio of 100:2.5. This is applied in a wet state to the surface of a substrate made of medium density fiberboard (MDF) of hardwood with a thickness of 2.5 mm. 2 Next, the undercoat layer of specimen 1A and the adhesive layer of the substrate were attached to each other and cured for three days to prepare specimen 1B of the decorative board.

[0090] Test specimen 2 A decorative sheet specimen 2A and a decorative board specimen 2B were produced under the same conditions as those for specimen 1, except that the amount of nucleating agent mixed was 0.02 parts by mass.

[0091] Comparison body 1 A comparative decorative sheet specimen 1A and a comparative decorative board specimen 1B were produced under the same conditions as those of specimen 1, except that the amount of nucleating agent mixed was 0.05 parts by mass.

[0092] Comparison body 2 A comparative decorative sheet sample 2A and a comparative decorative board sample 2B were produced under the same conditions as those of test sample 1, except that the amount of nucleating agent mixed was 0.1 parts by mass.

[0093] Comparison 3 Comparative decorative sheet specimen 3A and comparative decorative board specimen 3B were produced under the same conditions as specimen 1, except that the amount of nucleating agent mixed was 0 parts by mass, that is, mixing of the nucleating agent was omitted.

[0094] [Test Method] <Coin scratch test> A 10 yen coin was placed on the surface (surface protection layer) of decorative sheet specimens 1A, 2A and comparative specimens 1A-3A, and the condition of the surface was visually confirmed by moving the coin while applying a load to it. The load was increased in 1 kg increments from 1 kg to 4 kg and tests were performed. The results are shown in Table 1. In Table 1, "○" indicates that no continuous scars were produced even with a load of 2 kg or more, and "×" indicates that continuous scars were produced with a load of 2 kg or less.

[0095] <DuPont impact test> Plywood (12 mm thick) was further attached to the substrate of decorative laminate test specimens 1B, 2B and comparative specimens 1B to 3B, and a 500 g weight was dropped from a height of 50 cm using an impact tester conforming to "6. DuPont method" of "Weight drop resistance" specified in the Japanese Industrial Standards (JIS) "K5600-5-3", and the surface condition was visually confirmed. The results are shown in Table 1. In Table 1, "○" indicates that no cracks were generated, and "×" indicates that cracks were generated.

[0096] [Test Results] The results of the above tests are shown in Table 1 below.

[0097] [Table 1]

[0098] As can be seen from Table 1, Comparative Samples 1 and 2 did not produce continuous scars at loads of 2 kg or more in the scratch test, but failed the impact test. On the other hand, Comparative Sample 3 (without nucleating agent) performed well in the impact test, but produced continuous scars at loads of 2 kg or less in the scratch test. In contrast, Samples 1 and 2 not only did not produce continuous scars at loads of 2 kg or more in the scratch test, but also performed well in the impact test.

[0099] From the above, it is recognized that the decorative sheet and decorative board according to the present invention can not only exhibit excellent scratch resistance, but also exhibit excellent impact resistance. [Industrial Applicability]

[0100] The decorative sheet and decorative board of the present invention can not only exhibit excellent scratch resistance, but also excellent impact resistance, and can therefore be used extremely beneficially in various industries, including the construction industry. [Explanation of symbols]

[0101] 10 Decorative Sheet 10a Emboss 11 Colored resin layer 12 Picture layer 13 Transparent resin layer 14 Surface protective layer 14a Undercoat layer 14b Top coat layer 20 Decorative Sheet 25 Base layer 100 Veneer 101 Substrate 102 Adhesive layer

Claims

1. A colored resin layer containing a polyolefin resin; A pattern layer provided on the colored resin layer; a transparent resin layer provided on the pattern layer and containing a crystalline polypropylene resin; a surface protection layer provided on the transparent resin layer, the surface protection layer having at least an outermost surface containing an ultraviolet curable resin; In the decorative sheet, The transparent resin layer is formed by containing 0.01 parts by mass or more and 0.02 parts by mass or less of a nano-sized nucleating agent with respect to 100 parts by mass of the crystalline polypropylene resin. A decorative sheet characterized by:

2. The surface protective layer is A topcoat layer containing an ultraviolet-curable resin located on the surface side; an undercoat layer located on the transparent resin layer side and containing a two-component curing resin; It has two layers:

2. The decorative sheet according to claim 1.

3. The crystalline polypropylene resin is a highly crystalline polypropylene resin having an isotactic pentad fraction (mmmm fraction) of 95% or more.

2. The decorative sheet according to claim 1.

4. The nucleating agent is encapsulated in a vesicle.

2. The decorative sheet according to claim 1.

5. The vesicle has an outer membrane containing at least one of a polymeric surfactant, a fatty acid metal salt, a silane coupling agent, a titanate coupling agent, a silicone, a wax, and a modified resin.

5. The decorative sheet according to claim 4.

6. The vesicle has a single-layer outer membrane containing phospholipids.

5. The decorative sheet according to claim 4.

7. The decorative sheet according to any one of claims 1 to 6, A substrate provided on the back side of the decorative sheet; an adhesive layer provided between the decorative sheet and the substrate; A decorative panel comprising:

Images