Decorative sheet and decorative member

Abstract

To provide a decorative sheet which hardly causes changes in appearance when subjected to a stretching load.SOLUTION: There is provided a decorative sheet comprising at least a colored resin layer, a printing layer and a transparent resin layer in this order, which satisfies all of the following conditions (1) to (3). (1) Both of the colored resin layer and the transparent resin layer are an olefin-based thermoplastic resin layer. (2) At least one or both of the colored resin layer and the transparent resin layer contain a fibrous material composed mainly of cellulose. (3) The aspect ratio defined by the (average fiber length / average fiber diameter) of the fibrous material is 1 or more and less than 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a decorative sheet and a decorative member. [Background technology]

[0002] Decorative sheets used for the surface decoration of building materials can be broadly divided into those based on a paper layer and those based on a resin layer. In Japan, around the year 2000, polyolefin layers began to be used more frequently than PVC layers as the resin layer material for decorative sheets. Polyolefins have many advantages, such as not generating dioxin gas when burned, not using plasticizers that are suspected to have adverse effects on the human body, and having a light specific gravity and high heat resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3089957 Summary of the Invention [Problem to be solved by the invention]

[0004] However, polyolefin layers have a high surface resistivity and are easily charged with static electricity, which means that decorative sheets with polyolefin layers have the problem that the static electricity that builds up on the decorative sheet attracts surrounding dust and dirt, and that the attracted dust and dirt is difficult to remove by cleaning (especially in very narrow areas).

[0005] The present invention has been devised to solve such problems, and an object of the present invention is to provide a decorative sheet that can reduce the surface resistivity. [Means for solving the problem]

[0006] [1] A decorative sheet comprising at least a colored resin layer, a printed layer, and a transparent resin layer in this order, A decorative sheet that meets all of the following conditions (1) to (3). (1) Both the colored resin layer and the transparent resin layer are olefin-based thermoplastic resin layers. (2) At least one of or both of the colored resin layer and the transparent resin layer contains a fibrous material whose main component is cellulose. (3) The aspect ratio of the fibrous material, defined as (average fiber length / average fiber diameter), is 1 or more and less than 10. [2] The decorative sheet according to [1], wherein only the transparent resin layer of the colored resin layer and the transparent resin layer contains the fibrous material whose main component is cellulose. [3] The decorative sheet according to [1] or [2], wherein the transparent resin layer contains the fibrous material at a concentration of 0.1 to 5.0% by mass. [4] At least one of the colored resin layer and the transparent resin layer containing the fibrous material contains a polyolefin graft-polymerized with a carboxylic acid anhydride. The decorative sheet according to any one of [1] to [3]. [5] The decorative sheet according to [4], wherein the carboxylic acid anhydride is maleic anhydride. [6] A decorative member comprising a substrate and the decorative sheet according to any one of [1] to [5] attached onto the substrate. [Effects of the Invention]

[0007] According to the present invention, the surface resistivity of the decorative sheet can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view illustrating a decorative sheet according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (decorative sheet) An example of the decorative sheet of the present invention will be described with reference to FIG.

[0010] As shown in FIG. 1, the decorative sheet 100 comprises at least a colored resin layer 10, a printed layer 20, and a transparent resin layer 30 in this order.

[0011] (Colored resin layer 10) The colored resin layer 10 is an olefin-based thermoplastic resin layer. An olefin-based thermoplastic resin is a resin whose main component is polyolefin. Examples of polyolefins include polyethylene, polypropylene, polybutene, copolymers of ethylene and one or more α-olefins, and copolymers of two or more α-olefins. Examples of α-olefins include 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-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene.

[0012] "Polyolefin as the main component" means that polyolefin is the largest component, and the amount of polyolefin may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more.

[0013] The colored resin layer 10 may contain multiple types of polyolefins.

[0014] The colored resin layer 10 may contain a polyolefin graft-polymerized with a carboxylic acid anhydride. An example of the carboxylic acid anhydride is maleic anhydride. The amount of the polyolefin graft-polymerized with the carboxylic acid anhydride may be 0.1% by mass or more and 20% by mass or less of the total polyolefin.

[0015] The colored resin layer 10 contains a colorant such as a pigment. Examples of the pigment include inorganic pigments such as metal oxides, such as titanium oxide and iron oxide, and composite oxides, such as iron-zinc oxide, chromium-antimony oxide, and iron-aluminum oxide. The hue of the base color of the printed layer 20 can be selected appropriately depending on the type of colorant.

[0016] The amount of colorant in the colored resin layer 10 may be 0.1% by mass or more and 30% by mass or less.

[0017] The types and compositions of the polyolefin, colorant, and fibrous material in the colored resin layer can be appropriately selected in consideration of ease of sheeting, printability, and suitability for bending.

[0018] The colored resin layer 10 may contain a fibrous material mainly composed of cellulose, which will be described in detail in the section on the transparent resin layer 30. The type and concentration of the fibrous material mainly composed of cellulose can be as described in the section on the transparent resin layer 30, which will be described later.

[0019] It is preferable that the colored resin layer 10 does not contain a fibrous material whose main component is cellulose. When the decorative sheet is in use, the surface exposed to the outside is the transparent resin layer side, not the colored resin layer side, and by including a fibrous material whose main component is cellulose in the transparent resin layer but not in the colored resin layer, the surface resistivity of the decorative sheet can be efficiently reduced with a small amount of added fibrous material.

[0020] The thickness of the colored resin layer 10 may be 3 μm or more, 20 μm or more, 60 μm or less, or 110 μm or less.

[0021] The colored resin layer may be formed by any method, for example, an extrusion molding method such as T-die molding or inflation molding.

[0022] (Printing layer) The printed layer 20 is a layer that forms a picture pattern to impart design to the decorative sheet 100. Various known printing methods can be used to form the printed layer 20. The printing method is not particularly limited, but gravure printing is preferred in consideration of productivity and pattern quality. Furthermore, for example, if the colored resin layer 10 can be prepared in a rolled state, the printed layer 20 can be formed using a roll-to-roll printing device. Other printing methods include, for example, offset printing, screen printing, flexographic printing, electrostatic printing, inkjet printing, and transfer printing from a transfer sheet. When using such a printing method, the picture pattern of the printing layer 20 can be formed by multi-color printing using the usual process colors of yellow, red, blue, and black, or by multi-color printing using special colors in which plates of the individual colors that make up the picture pattern are prepared.

[0023] The pattern of the printed layer 20 can be any pattern depending on the design of the flooring material or fitting. For example, a marble grain pattern can be used to evoke the image of a stone floor such as marble. Furthermore, for example, if a wood-based pattern is desired, various wood grains or cork can be used as the pattern. Furthermore, in addition to patterns of natural materials, artificial patterns based on these motifs or geometric patterns can also be used. In addition to these, other examples of pattern designs include wood grain patterns composed of spring wood and autumn wood regions in the cross section of tree rings, vessel parts, etc., leather (grain) patterns, stone grain patterns on the surface of stone materials such as marble, granite, and sandstone, sand grain patterns, tile patterns, brickwork patterns, fabric patterns, geometric shapes, letters, symbols, abstract patterns, floral patterns, landscapes, characters, etc.

[0024] The ink for forming the print layer is a mixture of a solvent and solid components such as a colorant and a binder resin.

[0025] Examples of solvents include petroleum-based organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ester-based organic solvents such as ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and 2-ethoxyethyl acetate; alcohol-based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, and propylene glycol; ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based organic solvents such as diethyl ether, dioxane, and tetrahydrofuran; chlorine-based organic solvents such as dichloromethane, carbon tetrachloride, trichloroethylene, and tetrachloroethylene; and inorganic solvents such as water. The solvents may be used alone or in combination of two or more.

[0026] Examples of binder resins include chlorine-based resins, urethane resins, acrylic urethane resins, acrylic resins, polyester resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins (nitrocellulose), and cellulose acetate resins. Examples of chlorine-based resins include polyvinyl chloride resins such as polyvinyl chloride, chlorinated polyethylene, polyvinylidene chloride, ethylene-vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, and vinyl chloride-vinyl acetate-(meth)acrylic copolymer, as well as polypropylene chloride and chlorinated polypropylene, where (meth)acrylic means acrylic or methacrylic. The binder resin may be a single type or a combination of two or more types.

[0027] Examples of colorants include inorganic pigments such as carbon black, iron black, titanium white (titanium oxide), antimony white, yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine blue, and cobalt blue; and organic pigments such as quinacridone red, isoindolinone yellow, and phthalocyanine blue. The colorant may be one type alone or two or more types in combination. The solvent contained in the printing ink will eventually volatilize, so the printed layer 20 is mainly formed from solid components such as colorants and binder resins.

[0028] The printing ink may also contain other components such as a stabilizer, a plasticizer, a catalyst, and a curing agent. The printing ink may be selected in accordance with the printing method, taking into consideration in particular the adhesion to the colored resin layer 10, printability, and weather resistance as a flooring material or fitting. The thickness of the printed layer 20 can be adjusted as appropriate, taking into consideration the decorative properties required of the printed layer 20, the three-dimensional formability of the decorative sheet 100, etc. The thickness of the printed layer 20 is usually 1 μm or more and 1 mm or less, preferably 2 μm or more and 0.1 mm or less, and more preferably 2 μm or more and 50 μm or less.

[0029] (adhesive layer 25) For the purpose of improving the adhesion between the printing layer 20 and the transparent resin layer 30, an adhesive layer 25 may be provided on the surface of the printing layer 20 that comes into contact with the transparent resin layer 30. By strengthening this adhesion, it may become easier to impart bending processability to the decorative sheet 100 so that it can follow curved surfaces and right-angled surfaces. The resin used for the adhesive layer 25 is not particularly limited. For example, a two-component curing urethane resin can be used. Alternatively, the adhesive layer can be formed by adhering an adhesive resin to the printing layer 20 with a urethane adhesive. For example, a coating device or a gravure printing device can be used to apply the resin used for the adhesive layer 25. The thickness of adhesive layer 25 may be 0.1 μm or more, 1 μm or more, 5 μm or less, or 15 μm or less.

[0030] (Transparent resin layer) The transparent resin layer 30 is a resin layer that not only adds thickness and depth for design purposes, but also protects the printed layer 20 and imparts good surface properties to improve the weather resistance and abrasion resistance of the decorative sheet 100. The transparent resin layer 30 is an olefin-based thermoplastic resin layer. An olefin-based thermoplastic resin is a resin whose main component is polyolefin. Examples of polyolefins include polyethylene, polypropylene, polybutene, copolymers of ethylene and one or more α-olefins, and copolymers of two or more α-olefins. Examples of α-olefins include 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-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene.

[0031] "Polyolefin as the main component" means that polyolefin is the largest component, and the amount of polyolefin may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more.

[0032] The transparent resin layer 30 may contain multiple types of polyolefins.

[0033] The transparent resin layer 30 may contain a polyolefin graft-polymerized with a carboxylic acid anhydride. An example of the carboxylic acid anhydride is maleic anhydride. The amount of the polyolefin graft-polymerized with the carboxylic acid anhydride may be 0.1% by mass or more and 20% by mass or less of the total polyolefin.

[0034] When the transparent resin layer contains a polyolefin graft-polymerized with a carboxylic acid anhydride, the compatibility between the polyolefin and the fibrous material whose main component is cellulose is improved, and poor appearance due to poor dispersion of the fibrous material is suppressed.

[0035] The transparent resin layer 30 does not contain a colorant such as a pigment, for example, titanium oxide.

[0036] (fibrous material whose main component is cellulose) The transparent resin layer 30 contains a fibrous material whose main component is cellulose.

[0037] Examples of fibrous materials whose main component is cellulose include plant fibers, recycled fibers, acetate-based fibers (diacetate and triacetate), pulp fibers, and cellulose fibers.

[0038] Examples of plant fibers include cotton and hemp.

[0039] Examples of acetate-based fibers include acetate fibers, diacetate fibers, and triacetate fibers.

[0040] Examples of regenerated fibers include rayon and cupra.

[0041] Pulp fibers are fibers obtained by removing lignin and hemicellulose from plant fibers.

[0042] The cellulose fibers are fibers obtained by defibrating pulp fibers. The diameter of the cellulose fibers may be 1 μm or more, or may be less than 1 μm. The diameter of the cellulose fibers may be 0.003 to 10 μm.

[0043] The cellulose in the fibrous material may be modified with a hydrophobic functional group such as fluorene.

[0044] A fibrous material containing cellulose as a main component, such as cellulose fiber, may contain at least one of hemicellulose and lignin in addition to cellulose. Cellulose may account for 50% by mass or more, or 70% by mass or more, of the fibrous material.

[0045] The aspect ratio of the cellulose-based fibrous material is equal to or greater than 1 and less than 10. The aspect ratio may be 9.0 or less, 8.0 or less, 7.0 or less, 6.0 or less, or 5.0 or less.

[0046] The aspect ratio of a cellulose-based fibrous material is defined as (average fiber length / average fiber diameter). Specifically, the fiber diameter and fiber length of any 20 fibers in a transmission electron microscope image of the transparent resin layer are obtained, and the aspect ratio can be calculated as the ratio of the average fiber length to the average fiber diameter.

[0047] The aspect ratio of the fibrous material in the transparent resin layer can vary not only depending on the aspect ratio of the fibrous material at the raw material stage of resin production, but also on the kneading conditions during the production of the transparent resin layer.

[0048] By melt-kneading the polyolefin, colorant, and fibrous material in a device with high shear such as a twin-screw extruder, the aspect ratio of the fibrous material can be made sufficiently smaller than that of the raw material. In particular, in a twin-screw kneader, the use of a polyolefin with a small MFR, kneading at a relatively low temperature, and / or applying high shear to the raw materials by adjusting the screw elements are effective.

[0049] The diameter of the fibrous material may be 0.003 to 10 μm, and from the viewpoint of increasing transparency, it may be 5 μm or less, or may be less than 1 μm.

[0050] The amount of fibrous material containing cellulose as a main component in the transparent resin layer may be 0.1% by mass or more, 0.2% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 1.0% by mass or more, 10% by mass or less, 7.0% by mass or less, 6.0% by mass or less, or 5.0% by mass or less. By setting the amount of cellulose-based fiber material to 0.1 parts by mass or more, the effect of reducing surface resistivity is easily achieved, and by setting it to 5.0 parts by mass or less, discoloration of the transparent resin layer is easily suppressed.

[0051] The thickness of the transparent resin layer 30 may be 20 μm or more, 50 μm or more, 70 μm or less, or 120 μm or less.

[0052] The transparent resin layer may be formed by any method, for example, an extrusion molding method such as T-die molding or inflation molding. The obtained transparent resin layer 30 can be laminated to the printed layer side of the colored resin layer via an adhesive or the like. Furthermore, for example, when the transparent resin layer 30 and the adhesive layer 25 are formed simultaneously, a method of forming them by co-extrusion can be employed.

[0053] (Surface protective layer 40) The surface protective layer 40 is a layer that provides surface properties such as abrasion resistance to the decorative sheet 100. The surface protective layer 40 also serves to adjust the gloss of the surface of the decorative sheet 100. The surface protective layer 40 may be a single layer or multiple layers.

[0054] For example, the surface protective layer 40 may be formed by providing two layers, a first surface protective layer and a second surface protective layer, in this order on the transparent resin layer 30 . When providing a surface protection layer 40 consisting of a first surface protection layer and a second surface protection layer, each layer may be applied and the coating film may be hardened using a known coating device, heat drying device, or ionizing radiation irradiation device depending on the type of curable resin. Preferably, the surface protective layer 40 is primarily composed of a curable resin, i.e., the resin component of the surface protective layer 40 is substantially composed of a curable resin. "Substantially" refers to, for example, 80 parts by mass or more when the total resin is 100 parts by mass. The surface protective layer 40 may contain weathering agents, plasticizers, stabilizers, fillers, dispersants, colorants such as dyes and pigments, solvents, etc., as needed.

[0055] For example, an ionizing radiation curable resin or a two-component curable urethane resin can be used as the material of the surface protection layer 40. The ionizing radiation curable resin is not particularly limited. For example, a transparent resin can be used whose main component is a prepolymer (including oligomer) and / or monomer containing a radically polymerizable double bond in the molecule that can undergo polymerization and crosslinking reaction upon irradiation with ionizing radiation such as infrared rays, ultraviolet rays, or electron beams. These prepolymers or monomers can be used alone or in combination. Specific examples of prepolymers or monomers include compounds having radically polymerizable unsaturated groups such as (meth)acryloyl groups and (meth)acryloyloxy groups, and cationically polymerizable functional groups such as epoxy groups in the molecule. Also preferred is a polyene / thiol-based prepolymer obtained by combining a polyene with a polythiol. Here, the (meth)acryloyl group means an acryloyl group or a methacryloyl group.

[0056] Examples of prepolymers having a radically polymerizable unsaturated group include polyester (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, triazine (meth)acrylate, silicone (meth)acrylate, etc. The molecular weight of these is preferably about 250 to 100,000. Furthermore, examples of the monomer having a radically polymerizable unsaturated group include monofunctional monomers such as methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and phenoxyethyl (meth)acrylate. Examples of polyfunctional monomers include diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylpropane tri(meth)acrylate, trimethylolpropane ethylene oxide tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0057] Examples of prepolymers having a cationically polymerizable functional group include prepolymers of epoxy resins such as bisphenol-type epoxy resins and novolac-type epoxy compounds, and vinyl ether resins such as fatty acid vinyl ethers and aromatic vinyl ethers. Furthermore, examples of polyene-based prepolymers include those in which allyl alcohol is added to both ends of polyurethane made from diol and diisocyanate. Examples of thiol-based prepolymers include polythiols such as trimethylolpropane trithioglycolate and pentaerythritol tetrathioglycolate.

[0058] The ionizing radiation may be, for example, electromagnetic waves or charged particles having enough energy to cause a curing reaction of molecules in the ionizing radiation curable resin (composition). Examples of the curing reaction include crosslinking curing reactions. The ultraviolet light source may be, for example, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light, or a metal halide lamp. The wavelength of the ultraviolet light is preferably, for example, 190 nm or more and 380 nm or less. As the electron beam source, for example, an electron beam accelerator such as a Cockcroft-Walton type, a Van de Graaff type, a resonant transformer type, an insulating core transformer type, a linear type, a dynamitron type, a high frequency type, etc. is usable. In particular, one that can irradiate electrons having an energy of 100 keV or more and 1000 keV or less (more preferably, electrons having an energy of 100 keV or more and 300 keV or less) is preferred.

[0059] The two-component curing urethane resin is not particularly limited. For example, it may contain a polyol component having OH groups as the main component and an isocyanate component as the curing agent. Examples of the polyol component having OH groups include acrylic polyol, polyester polyol, polyether polyol, and epoxy polyol. Examples of the isocyanate component include tolylene diisocyanate, hexamethylene diisocyanate, and metaxylene diisocyanate.

[0060] The thickness of the surface protection layer 40 may be 3 μm or more, 9 μm or more, 12 μm or less, or 21 μm or less.

[0061] (Primer coating layer 50) The primer coat layer 50 can be provided on the side of the colored resin layer 10 opposite the printed layer 20. The primer coat layer 50 is a layer for improving adhesion and corrosion resistance with a substrate (not shown) to which the decorative sheet 100 is attached.

[0062] The primer coating layer 50 is formed using, for example, a polyester resin, an organic additive, a pigment, etc. The primer coating layer 50 may contain an anti-rust pigment to improve corrosion resistance. The thickness of the primer coating layer 50 is, for example, in the range of 1 μm to 10 μm.

[0063] (Transformation mode) In the above embodiment, the transparent resin layer 30 contains a fibrous material whose main component is cellulose, but the transparent resin layer 30 may not contain a fibrous material whose main component is cellulose, and instead, the colored resin layer 10 may contain a fibrous material whose main component is cellulose.

[0064] (Action and effect) According to the decorative sheet of this embodiment, it is possible to reduce the surface resistivity while having an olefin-based thermoplastic resin layer. The reason for this is unclear, but the following is thought to be the case. In the decorative sheet of this embodiment, at least one of the colored resin layer and the transparent resin layer contains a fibrous material whose main component is cellulose. This fibrous material has hydrophilic groups such as hydroxyl groups, and therefore can adsorb water in the environment through hydrogen bonding or the like, contributing to a reduction in surface resistivity. Furthermore, an aspect ratio of the fibrous material of 1 or more and less than 10 means that the fibrous material has an extremely large number of cut surfaces, i.e., a large specific surface area, which is thought to enhance the effect of water adsorption by the hydrophilic groups.

[0065] (decorative materials) The decorative member according to this embodiment includes a substrate and the decorative sheet described above attached to the substrate. Examples of the substrate are not particularly limited, and include plywood (such as linden, oak, and lauan), MDF (medium density fiberboard), etc. The decorative sheet may be attached to the substrate using various adhesives. [Example]

[0066] Examples 1 to 4 A printed layer was applied to a random PP-based colored base film (manufactured by Riken Technos, OW, thickness 60 μm) as a colored resin layer using an inkjet printer (manufactured by Muto Industries, PerformanceJet PJ-2508UF).

[0067] A cellulose nanofiber PP masterbatch (T-NC316 manufactured by Seiko PMC, cellulose concentration 40%), random PP (B241 manufactured by Prime Polymer, MFR=0.5), and maleic acid-modified PP (Umex 1001 manufactured by Sanyo Chemical Industry) were mixed and pelletized at a set temperature of 130°C using a twin-screw extruder in the formulation shown in Table 1. The mixture was then extruded into pellets at a thickness of 100 μm using a single-screw T-die extruder to create a transparent resin layer containing cellulose fiber. When the aspect ratios of the cellulose fibers in the transparent resin layer were observed using an electron microscope, they were all found to be in the range of 1 or more and less than 10, due to the cellulose being broken by the high shear force applied to the resin during twin-screw extrusion.

[0068] After corona treatment was applied to both sides of the created transparent resin layer, an isocyanate-curing polyester adhesive (Tomoflex TM593: base agent, CAT-RA85: hardener, both manufactured by Toyo-Morton) was applied using a wire bar at a coating amount of 5g / m2 (after drying), and the printed layer side of the previously prepared colored resin layer was then attached.

[0069] Next, a UV-curable acrylic resin coating agent was applied to the outermost surface of the transparent resin layer using a wire bar at a coating amount of 10 g / m2 (after drying), and then cured with LED-type UV light to create a surface protection layer.

[0070] For the colored resin layer, a medium ink (V350 manufactured by Toyo Ink) containing no pigment component was applied as a primer coat layer by wire bar coating at a coating thickness of 1 g / m 2 (after drying), to obtain decorative sheets of Examples 1-4.

[0071] (Comparative Example 1) A decorative sheet of Comparative Example 1 was obtained with the formulation shown in Table 1 in the same manner as in Example 1, except that the cellulose nanofiber masterbatch was not added.

[0072] (Comparative Example 2) A decorative sheet of Comparative Example 2 was produced in the same manner as Example 1, except that pelletization by kneading using a twin-screw extruder was not performed, and the dry blend was kneaded and extruded in a single-screw extruder as is. By not using twin-screw extrusion, high shear force was not applied to the resin, and the aspect ratio of the cellulose fiber was 330.

[0073] (evaluation) (Surface resistivity) After leaving the decorative sheet undisturbed for 24 hours in an environment with a temperature of 20°C and humidity of 40%, the surface resistivity was measured (the median value of five measurements is displayed to one significant digit) using a surface resistance measuring device (Hiresta-UX MCP-HT800 manufactured by Nitto Seiko Analytech) in accordance with JIS C2139-3-2.

[0074] (exterior) The color tone as a decorative sheet was confirmed by visual inspection. The conditions and evaluation are shown in Table 1.

[0075] [Table 1] [Explanation of symbols]

[0076] 20...printed layer, 10...colored resin layer, 30...transparent resin layer, 100...decorative sheet.

Claims

1. A decorative sheet comprising at least a colored resin layer, a printed layer, and a transparent resin layer in this order, A decorative sheet that satisfies all of the following conditions (1) to (3): (1) Both the colored resin layer and the transparent resin layer are olefin-based thermoplastic resin layers. (2) At least one of or both of the colored resin layer and the transparent resin layer contains a fibrous material whose main component is cellulose. (3) The aspect ratio of the fibrous material, defined as (average fiber length / average fiber diameter), is 1 or more and less than 10.

2. 2. The decorative sheet according to claim 1, wherein only the transparent resin layer of the colored resin layer and the transparent resin layer contains the fibrous material containing cellulose as a main component.

3. 3. The decorative sheet according to claim 1, wherein said transparent resin layer contains said fibrous material in a concentration of 0.1 to 5.0% by mass.

4. 3. The decorative sheet according to claim 1, wherein at least one of the colored resin layer and the transparent resin layer containing the fibrous material contains a polyolefin graft-polymerized with a carboxylic acid anhydride.

5. 5. The decorative sheet according to claim 4, wherein said carboxylic acid anhydride is maleic anhydride.

6. A decorative member comprising a substrate and the decorative sheet according to claim 1 or 2 attached to the substrate.

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