Decorative film

Abstract

To provide a decorative film that exhibits high performance in ultraviolet shielding, toughness, heat resistance, dimensional stability, and the like.SOLUTION: A decorative film comprises, as its constituent, a film composed of a polyethylene-based thermoplastic resin composition, the composition containing 100 pts.wt. of a polyethylene-based thermoplastic resin (A) in combination with 1 to 60 pts.wt. of cellulose nanofiber (B) having an average fiber diameter of 1 to 1,000 nm and 1 to 20 pts.wt. of at least one inorganic ultraviolet shielding agent (C) selected from the group consisting of zinc oxide, titanium oxide, platinum, aluminum, palladium, cerium oxide, iron oxide, silica, aluminum oxide, and zirconium dioxide.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a decorative film. [Background technology]

[0002] Decorative films are films (or sheets) decorated by printing, painting, vacuum deposition, coloring, etc., which are attached to the surface of molded products, or only the design layer is transferred to the molded products. The basic structure of decorative films is, for example, a resin film (substrate film or sheet) / adhesive layer / decorative layer / hard coat layer / peeling layer. The main purpose of decorative films has traditionally been to provide surface designs (metallic, wood grain, embossed, mesh, grain, etc.), hard coats, anti-reflection, etc., but in recent years, new functions such as water repellency, heat insulation, heat shielding, UV shielding, near infrared shielding, heat dissipation, antibacterial and antiviral properties, electromagnetic wave shielding, inkjet printing, and 3D printer decoration have been considered. In particular, when a molded product to which a decorative film is attached is used in an outdoor environment, the UV shielding property of the decorative film is important in order to suppress deterioration and discoloration of the decorative film itself due to UV rays, or deterioration and discoloration of the molded product to which the decorative film is attached. Methods for bonding decorative film to molded products include in-mold molding (IM-D, IM-L), in which the decorative film is inserted into a mold and then molten resin is injected to bond the film to the surface of the molded product, and out-mold molding (OMD).

[0003] On the other hand, painting has been commonly used as a method of decorating the surface of molded products, but problems have been pointed out with painting using solvents, such as low production efficiency due to manual work, low yield, dirty work sites, large carbon dioxide emissions and energy consumption in the drying process of the solvent, compliance with VOC (volatile organic compound) emission standards, and the need for measures to prevent health damage to workers. In addition, improvements have been made with powder paints and water-based paints, but there are concerns about health damage from inhalation of powder paints, and while water-based paints do not emit VOCs, they have problems such as large energy consumption in the drying process and the need for wastewater treatment. On the other hand, film decoration does not use solvents and has features such as high precision, high productivity, labor saving, and high yield, so in recent years it has been attracting attention as a paint-free method, mainly in the automotive field.

[0004] Here, cellulose nanofiber is a biomass material derived from plants, and has characteristics such as light weight, high strength, low dimensional change rate, and thixotropy. Therefore, many materials and molded products have been proposed that incorporate it into inks, adhesives, plastics, etc. (see, for example, Patent Documents 1 to 3). Also, decorative films having ultraviolet shielding properties have been proposed (see, for example, Patent Documents 4 to 7), and an ultraviolet shielding sealant film for packaging materials has been proposed (see, for example, Patent Document 8). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7248988 [Patent Document 2] Patent No. 7303015 Publication [Patent Document 3] Patent Publication No. 2021-109911 [Patent Document 4] Patent No. 5910272 [Patent Document 5] Patent No. 6681562 [Patent Document 6] Patent Publication No. 2021-30584 [Patent Document 7] JP 2023-39963 A [Patent Document 8] Patent No. 7218505 Summary of the Invention [Problem to be solved by the invention]

[0006] The compositions containing cellulose nanofibers proposed in Patent Documents 1 to 3 do not state anything about decoration. In addition, for the decorated films described in Patent Documents 4 to 7, organic ultraviolet shielding agents are proposed as ultraviolet shielding agents, but the organic ultraviolet shielding agents volatilize during melt kneading or melt molding, generating gas and causing deterioration in the film appearance. In addition, when used for a long period of time, there is a problem that the agent bleeds out onto the film surface, causing deterioration in the film appearance and decreasing the ultraviolet shielding property. Furthermore, the film described in Patent Document 8 does not state anything about decoration, and has problems such as insufficient heat resistance and dimensional stability.

[0007] Therefore, an object of the present invention is to provide a decorative film that is excellent in ultraviolet shielding properties, toughness, heat resistance, dimensional stability, appearance, and the like. [Means for solving the problem]

[0008] Means for Solving the Problems The present inventors conducted intensive research to solve the above problems and discovered that a decorative film comprising a film made of a polyethylene thermoplastic resin composition containing a polyethylene thermoplastic resin, specific cellulose nanofibers, and a specific ultraviolet blocking agent is excellent in ultraviolet blocking properties, toughness, heat resistance, dimensional stability, etc., and thus completed the present invention.

[0009] That is, the respective aspects of the present invention are [1] to [4] shown below. [1] A decorative film comprising, as a component, a film made of a polyethylene thermoplastic resin composition containing, per 100 parts by weight of a polyethylene thermoplastic resin (A), 1 to 60 parts by weight of cellulose nanofibers (B) having an average fiber diameter of 1 to 1,000 nm, and 1 to 20 parts by weight of at least one inorganic ultraviolet ray blocking agent (C) selected from the group consisting of zinc oxide, titanium oxide, platinum, aluminum, palladium, cerium oxide, iron oxide, silica, aluminum oxide, and zirconium dioxide. [2] The decorative film according to [1], wherein the cellulose nanofiber (B) is a cellulose nanofiber in which the hydroxyl groups of cellulose are acetylated or acylated. [3] The decorative film according to any one of [1] to [2], wherein the polyethylene-based thermoplastic resin composition further contains 1 to 10 parts by weight of an organic ultraviolet ray shielding agent (D). [4] The decorative film according to any one of [1] to [3], wherein the polyethylene-based thermoplastic resin composition further contains 10 to 100 parts by weight of a biomass resin (E). Effect of the Invention

[0010] According to the present invention, it is possible to provide a decorative film that does not emit VOCs and has excellent UV shielding properties, toughness, heat resistance, dimensional stability, appearance, etc., for decorating the surface of a molded article with high productivity and high yield, and the industrial value of the film is extremely high. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below.

[0012] The polyethylene-based thermoplastic resin constituting the decorative film of the present invention may be, for example, a homopolymer such as high-density polyethylene, medium-density polyethylene, branched low-density polyethylene, linear low-density polyethylene, or ultra-high molecular weight polyethylene, or may be an ethylene-α-olefin copolymer. In the case of an ethylene-α-olefin copolymer, examples of the α-olefin include propylene, 1-butene, 4-methyl-1-pentene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-hexadecene, and 1-octadecene. In addition, an ethylene-based copolymer may be used. In the case of ethylene-based copolymers, examples of ethylene-based copolymers include ethylene-vinyl acetate copolymers, saponified ethylene-vinyl acetate copolymers, ethylene-α,β-unsaturated carboxylic acid alkyl ester copolymers, ethylene-maleic anhydride copolymers, ethylene-α,β-unsaturated carboxylic acid alkyl ester-maleic anhydride copolymers, ethylene-α,β-unsaturated carboxylic acid glycidyl ester copolymers, ethylene-α,β-unsaturated carboxylic acid glycidyl ester-vinyl acetate copolymers, and ethylene-α,β-unsaturated carboxylic acid glycidyl ester-α,β-unsaturated carboxylic acid alkyl ester copolymers. The density of the polyethylene thermoplastic resin is not particularly limited, but is usually 0.890 to 0.975 g / cm. 3 Since it is easy to obtain mechanical strength, it is 0.910 to 0.960 g / cm 3 It is more preferable that the polyethylene thermoplastic resin is one of these. It is also possible to use these polyethylene thermoplastic resins alone or in combination.

[0013] Furthermore, the melt flow rate (MFR) of the polyethylene thermoplastic resin at 190°C under a load of 2.16 kg is not particularly limited, but is usually preferably 0.01 to 80 g / 10 min, and more preferably 0.05 to 50 g / 10 min in order to improve moldability.

[0014] The cellulose nanofiber (B) constituting the decorative film of the present invention may be any cellulose nanofiber containing material, and the cellulose that is the raw material of the cellulose nanofiber is generally known to be derived from plants such as wood, bamboo, hemp, rice, jute, kenaf, cotton, beet, oil palm, cloth, pulp, recycled pulp, waste paper, and agricultural waste such as olive oil extraction residue, or from algae, microorganisms (e.g., acetic acid bacteria) or animals (e.g., sea squirts), and any of these can be used in the present invention. Cellulose derived from plants or microorganisms is preferred, and cellulose derived from plants is more preferred. These cellulose nanofibers can be used alone or in combination. Furthermore, the cellulose nanofiber can also be used as a master batch in which it is previously incorporated into a polyethylene resin or the like.

[0015] The cellulose nanofiber (B) used in the present invention has an average fiber diameter of 1 to 1,000 nm. If the average fiber diameter of the cellulose nanofiber is less than 1 nm, the productivity of the cellulose nanofiber is low, and the production cost increases. On the other hand, if the average fiber diameter of the cellulose nanofiber exceeds 1,000 nm, the effect of improving the heat resistance and dimensional change rate by adding the cellulose nanofiber is poor, and many fish eyes are generated in the film, which deteriorates the appearance of the decorative film. The fiber length of the cellulose nanofiber is not particularly limited, but since the effect of improving the heat resistance and dimensional change rate by adding the cellulose nanofiber is particularly excellent, it is preferable that the fiber length / fiber diameter (aspect ratio) is 10 to 10,000. The average fiber diameter of the cellulose nanofiber is measured by observation with a scanning electron microscope (SEM) and calculated as the average diameter of 50 or more fibers.

[0016] Furthermore, the cellulose nanofibers can be produced by publicly known methods, for example, by mechanically opening the fibers using a twin-screw extruder, a Banbury mixer, a pressure kneader, a homogenizer, a media stirring mill, a vibration mill, a grinder, a ball mill, a high-pressure water jet, an ultrasonic dispersion processor, a beater, a disk refiner, a conical refiner, a double disk refiner, or the like.

[0017] Furthermore, the cellulose nanofiber constituting the present invention is preferably a hydrophobic cellulose nanofiber in which the hydroxyl groups of the cellulose nanofiber are acetylated or acylated, and by making the cellulose nanofiber acetylated or acylated, the dispersibility in a polyethylene-based thermoplastic resin is excellent, and a decorative film excellent in toughness, heat resistance and dimensional stability can be obtained. As a method for acetylating or acylating the hydroxyl groups of the cellulose nanofiber, a publicly known method can be used, and for example, a method of substituting the hydroxyl groups of cellulose with an acid anhydride such as acetic anhydride, propionic anhydride, butyric anhydride, pentanoic anhydride, hexanoic anhydride, decanoic anhydride, benzoic anhydride, stearic anhydride, maleic anhydride, succinic anhydride, phthalic anhydride, maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified diene polymer, or polybasic acid anhydride can be used. The degree of substitution of the hydroxyl groups of the cellulose nanofibers with acetyl or acyl groups is optimized as appropriate depending on the type of polyethylene resin, thermally conductive particles and / or thermally conductive fibers that constitute the present invention and the target physical properties. In order to obtain a decorative film with particularly excellent thermal conductivity, toughness, heat resistance and dimensional stability, the degree of substitution is preferably 0.3 to 1, and more preferably 0.5 to 1.

[0018] The amount of the cellulose nanofiber blended is 100 parts by weight of the polyethylene thermoplastic resin. When the amount of the cellulose nanofiber is less than 1 part by weight, the heat resistance and dimensional stability of the decorative film are poor, whereas when the amount of the cellulose nanofiber is more than 60 parts by weight, the toughness and moldability of the film are poor.

[0019] The inorganic ultraviolet shielding agent (C) constituting the decorative film of the present invention is at least one inorganic ultraviolet shielding agent selected from the group consisting of zinc oxide, titanium oxide, platinum, aluminum, palladium, cerium oxide, iron oxide, silica, aluminum oxide and zirconium dioxide. The inorganic ultraviolet shielding agent may be surface-treated in advance with a functional compound such as an epoxy compound, an isocyanate compound, a silicone compound or a titanate compound, or a polymer.

[0020] The amount of the inorganic ultraviolet shielding agent (C) is 1 to 20 parts by weight based on 100 parts by weight of the polyethylene thermoplastic resin (A). When the amount of the inorganic ultraviolet shielding agent is less than 1 part by weight, the ultraviolet shielding property of the decorative film is poor. On the other hand, when the amount of the inorganic ultraviolet shielding agent is more than 20 parts by weight, the film is poor in toughness, moldability, and appearance. The decorative film of the present invention is characterized by using the cellulose nanofiber and the inorganic ultraviolet shielding agent in combination. An interaction occurs so that the inorganic ultraviolet shielding agent is supported by the cellulose nanofiber dispersed in the polyethylene thermoplastic resin, and the dispersion and orientation of the inorganic ultraviolet shielding agent in the polyethylene thermoplastic resin become uniform, and as a result, excellent ultraviolet shielding property is expressed by adding a smaller amount of the inorganic ultraviolet shielding agent.

[0021] Furthermore, the polyethylene thermoplastic resin composition constituting the present invention may contain an organic ultraviolet shielding agent (D) as necessary. Examples of the organic ultraviolet shielding agent include commonly known benzotriazole ultraviolet shielding agents, benzophenone ultraviolet shielding agents, triazine ultraviolet shielding agents, malonic acid ester ultraviolet shielding agents, oxalic acid anilide ultraviolet shielding agents, and benzoate ultraviolet shielding agents. The blending amount of the organic ultraviolet shielding agent per 100 parts by weight of the polyethylene thermoplastic resin is preferably 1 to 10 parts by weight, since it results in a decorative film excellent in ultraviolet shielding properties, heat resistance, dimensional stability, and appearance.

[0022] The polyethylene-based thermoplastic resin composition constituting the present invention may contain a biomass resin (E) useful for carbon neutrality. The biomass resin is generally classified into a type produced in a microorganism body, a type obtained by polymerizing a monomer obtained by fermenting, decomposing, and modifying biomass such as starch and fats and oils, and a type obtained by chemically modifying natural products such as polysaccharides, and examples thereof include polylactic acid, polyhydroxyalkanoate, polybutylene succinate, biomass polyethylene, biomass polypropylene, biomass polyethylene terephthalate, biomass polytrimethylene terephthalate, and biomass polyamide. The amount of the biomass resin (D) to be blended with respect to 100 parts by weight of the polyethylene-based thermoplastic resin is preferably 10 to 100 parts by weight because it is effective for carbon neutrality.

[0023] The polyethylene thermoplastic resin composition may be used by mixing various additives within the scope of the present invention, and may be one or more of conventional additives such as plasticizers such as polyalkylene oxide oligomer compounds, thioether compounds, ester compounds, and organic phosphorus compounds, slip agents, antiblocking agents, antioxidants, heat stabilizers, hindered amine light stabilizers, waxes, rosins, and terpenes. Furthermore, the polyethylene thermoplastic resin composition may be one or more of various thermoplastic resins such as polyester resins such as polyethylene terephthalate, polyamide resins such as polyamide 6, polyolefin resins such as polypropylene, polystyrene resins such as polystyrene, and polyurethane.

[0024] The polyethylene-based thermoplastic resin composition can be produced by feeding the polyethylene-based thermoplastic resin (A), the cellulose nanofibers (B), the inorganic ultraviolet blocking agent (C), and, if necessary, any additives and thermoplastic resins into an extruder, and extruding the resulting composition to form an image.

[0025] Examples of the method for producing the decorative film of the present invention include a method of co-extruding a film made of the polyethylene-based thermoplastic resin composition with a decorative layer, a hard coat layer, a peeling layer, etc.; a method of forming a decorative layer, a peeling layer, an adhesive layer, etc. on a film made of the polyethylene-based thermoplastic resin composition by a printing method such as gravure printing or screen printing; a method of laminating a film made of the polyethylene-based thermoplastic resin composition with a decorative layer, a hard coat layer and / or a peeling layer, etc. using an adhesive or pressure-sensitive adhesive by using a dry laminator or the like; a method of heat-sealing a film made of the polyethylene-based thermoplastic resin composition with a decorative layer, a hard coat layer, a peeling layer, etc.; a method of coating a film made of the polyethylene-based thermoplastic resin composition with a decorative layer, a hard coat layer, a peeling layer, an adhesive layer, etc. as a coating liquid; and a method of extrusion laminating the polyethylene-based thermoplastic resin composition on a film made of a decorative layer, a hard coat layer, a peeling layer, etc.

[0026] In addition, the decorative film of the present invention can also be laminated with films or membranes having functions such as heat dissipation, waterproofness, water repellency, scratch resistance, abrasion resistance, sliding properties, rust prevention, stain resistance, heat insulation, electromagnetic wave shielding, antibacterial properties, antiviral properties, chemical resistance, and flame retardancy as components.

[0027] The decorative film obtained by the present invention can be suitably used for the purpose of decorating portable devices such as smartphones, electric devices such as home appliances and car stereos, electronic devices such as notebook computers, interior and exterior materials for automobiles, interior and exterior materials for buildings and building materials, furniture, window glass, etc., and imparting properties such as ultraviolet shielding, heat dissipation, waterproofing, water repellency, scratch resistance, abrasion resistance, sliding properties, rust prevention, stain resistance, heat shielding, electromagnetic wave shielding, antibacterial properties, high virus resistance, chemical resistance, flame retardancy, etc. EXAMPLES

[0028] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. It is not something that is done.

[0029] The polyethylene-based thermoplastic resins used in the examples and comparative examples are shown below.

[0030] Low-density polyethylene (hereinafter referred to as PE (A-1)); manufactured by Tosoh Corporation, (product name) Petrothene 212, MFR 8.0 g / 10 min.

[0031] Ethylene-vinyl acetate copolymer (hereinafter referred to as PE (A-2)) manufactured by Tosoh Corporation, (product name) Ultrathene 751, MFR 5.7 g / 10 min.

[0032] Saponified ethylene-vinyl acetate copolymer (hereinafter referred to as PE (A-3)) manufactured by Tosoh Corporation, (product name) Mersen H6051, MFR 5.5g / 10min.

[0033] Polylactic acid (hereinafter referred to as PLA(E)); manufactured by NatureWorks, (product name) Ingeo4032D, MFR 4g / 10min.

[0034] Polypropylene (hereinafter referred to as PP(F)); manufactured by Japan Polypropylene Corporation, (product name) Novatec FA3KM, MFR = 10g / 10min.

[0035] Microcellulose fiber (hereinafter referred to as MCF (B-2)); manufactured by Rettenmaier Co., Ltd., (product name) ARBOCEL BC200, average fiber length 300 μm, number average fiber diameter 20 μm.

[0036] Pulp preparation example 8 kg (5 kg solids) of wet softwood unbleached kraft pulp (NUKP) was refined and repeatedly defibrated by refinery until the CSF reached 50 ml. 5,000 ml of acetic anhydride was added to the refined NUKP and reacted at 80°C for 4 hours. The reaction mixture was then cooled to 40°C and separated from the liquid, after which acetic anhydride and acetic acid were removed at 70°C under reduced pressure. The mixture was then dried under reduced pressure at 60°C for 20 hours to obtain acetylated NUKP. The acetyl group substitution degree of the obtained acetylated NUKP was 0.8.

[0037] Inorganic UV protection agents Zinc oxide (hereinafter referred to as C-1); manufactured by Hakusui Tech Co., Ltd., (product name) zinc oxide type 1.

[0038] Titanium oxide (hereinafter referred to as C-2): manufactured by Ishihara Sangyo Kaisha, Ltd., (product name) Typeque CR-63, titanium oxide coated with an alumina hydrate, a silica hydrate, and an organosilicon compound.

[0039] Organic UV protection agents Benzotriazole-based ultraviolet screening agent (hereinafter referred to as D-1); manufactured by Adeka Corporation, (product name) Adeka STAB LA-31. <Evaluation of UV resistance> A film made of a composition containing a thermoplastic resin, cellulose nanofibers, and an ultraviolet shielding agent was subjected to a weathering test for 500 hours using a Sunshine carbon arc lamp weathering tester (manufactured by Suga Test Instruments Co., Ltd., product name: Sunshine Super Long Life Weather Meter) in accordance with JIS D-205 WAN-1S. The ultraviolet resistance was evaluated according to the following formula (1) from the L value, a value, and b value of the film before the ultraviolet resistance test and the L value, a value, and b value after the ultraviolet resistance test. Films with a ΔE of 10 or less after the ultraviolet resistance test were judged to have excellent ultraviolet resistance. The L value, a value, and b value of the film before and after the ultraviolet resistance test were measured using a colorimeter (manufactured by Suga Test Instruments Co., Ltd., product name: SM Color Computer).

[0040] ΔE=((L1-L2) 2 +(a1-a2) 2 +(b1-b2) 2 (1) (Here, L1 is the L value before the UV resistance test, a1 is the a value before the UV resistance test, b1 is the b value before the UV resistance test, L2 is the L value after the UV resistance test, a2 is the a value after the UV resistance test, and b2 is the b value after the UV resistance test. <Measurement of linear expansion coefficient of decorative film> Using a laser interference method (double-path Michaelson type), a film sample with a width of 5 mm and a length of 5 mm was used, and measurements were taken at a temperature rise rate of 2°C / min and at a measurement temperature of 0°C to 50°C. It was determined that when the linear expansion coefficient was less than 100 ppm / K, the heat resistance and dimensional stability of the decorative film were excellent, and when the linear expansion coefficient was 100 ppm / K or more, the heat resistance and dimensional stability of the decorative film were poor. <Measurement of tensile breaking stress> The measurement was performed at a pulling speed of 200 mm / min in accordance with ISO 1872-2. When the tensile breaking strength was 15 MPa or more, the decorative film was judged to have excellent strength, and when the tensile breaking strength was less than 15 MPa, the decorative film was judged to have poor strength. <Measurement of tensile elongation at break> The measurement was performed at a tensile speed of 200 mm / min in accordance with ISO 1872-2. When the tensile breaking elongation was 15% or more, the toughness of the decorative film was judged to be excellent, and when the tensile breaking elongation was less than 15%a, the toughness of the decorative film was judged to be poor.

[0041] Example 1 100 parts by weight of PE (A-1), 80 parts by weight of PE (A-2), 15 parts by weight of acetylated NUKP, and 12 parts by weight of zinc oxide (C-1) were mixed uniformly in advance and fed into a hopper of a twin-screw extruder (manufactured by Japan Steel Works, Ltd., (product name) TEX-25αIII, L / D=55) having four kneading zones. Then, melt-kneading was performed under the condition that the cylinder temperature of the kneading zone was heated to 220°C, and a polyethylene-based thermoplastic resin composition in which acetylated NUKP and zinc oxide (C-1) were dispersed was produced. Then, the obtained polyethylene-based thermoplastic resin composition was fed into a film forming machine having a screw diameter of 15 mmφ equipped with a T-die having a discharge port width of 100 mm, and formed into a film having a thickness of about 80 μm at a temperature of 220°C. Then, the fiber diameter of the acetylated cellulose nanofiber (hereinafter referred to as CNF (B-1)) measured by observation with a scanning electron microscope (SEM) was 60 nm. The film made of the polyethylene-based thermoplastic resin composition was then decorated with a wood grain pattern by gravure printing. The results of the measurements and evaluations are shown in Table 1.

[0042] Examples 2 to 6 Decorative films were produced in the same manner as in Example 1, with the blending ratios of polyethylene resin (A), acetylated cellulose nanofiber (B-1), zinc oxide (C-1), titanium oxide (C-2), benzotriazole-based ultraviolet shielding agent (D-3), and polylactic acid (E) set as shown in Table 1. They were then evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. All of the decorative films obtained were excellent in ultraviolet shielding properties, toughness, heat resistance, and dimensional change rate.

[0043] Comparative Examples 1 to 7 The decorative films were produced in the same manner as in Example 1, with the blending ratios of polyethylene resin (A), acetylated cellulose nanofiber (B-1), microcellulose fiber (B-2), zinc oxide (C-1), titanium oxide (C-2), polylactic acid (E), and polypropylene (F) set as shown in Table 2. Then, the films were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. The decorative films obtained in Comparative Examples 1 and 3 were inferior in heat resistance and dimensional change rate. The decorative film obtained in Comparative Example 1 was inferior in strength, and the decorative films obtained in Comparative Examples 2, 4, 5, 6, and 7 were inferior in toughness. The decorative films obtained in Comparative Examples 2 and 5 were inferior in ultraviolet shielding property.

[0044] [Table 1]

[0045] [Table 2] [Industrial Applicability]

[0046] The present invention provides a decorative film that is excellent in ultraviolet shielding properties, toughness, heat resistance, dimensional stability, etc., and is useful for decorating and shielding ultraviolet rays from portable devices such as smartphones, electric devices such as home appliances and car stereos, electronic devices such as notebook computers, interior and exterior materials for automobiles, interior and exterior materials for buildings and building materials, furniture, window glass, etc.

Claims

1. The decorative film comprises, as a constituent, a film made of a polyethylene thermoplastic resin composition containing, per 100 parts by weight of a polyethylene thermoplastic resin (A), 1 to 60 parts by weight of cellulose nanofibers (B) having an average fiber diameter of 1 to 1,000 nm, and 1 to 20 parts by weight of at least one inorganic ultraviolet shielding agent (C) selected from the group consisting of zinc oxide, titanium oxide, platinum, aluminum, palladium, cerium oxide, iron oxide, silica, aluminum oxide, and zirconium dioxide.

2. The decorative film according to claim 1 , wherein the cellulose nanofiber (B) is a cellulose nanofiber in which a hydroxyl group of cellulose is acetylated or acylated.

3. The decorative film according to claim 1, wherein the polyethylene-based thermoplastic resin composition further comprises 1 to 10 parts by weight of an organic ultraviolet ray shielding agent (D).

4. The decorative film according to claim 1, wherein the polyethylene-based thermoplastic resin composition further comprises 10 to 100 parts by weight of a biomass resin (E).

Images