Method for manufacturing metallic tone decorative film

Abstract

To provide a method for manufacturing a metallic tone decorative film, different from a manufacturing method causing cracks without being limited to a specific metal, such as indium and tin easily exhibiting a sea island structure, excellent in reproducibility in a position and a size of a space between metals used as a penetration path of an electric wave and capable of simply producing a metallic tone decorative film having high-definition electric wave penetrability only by washing away with environmentally friendly water without using an etching solution harmful to an environment like a photolithography process.SOLUTION: A method for manufacturing a metallic tone decorative film having electric wave penetrability comprises: a water-soluble primer layer formation step of imparting a water-soluble primer composition along a predetermined pattern shape on a base material to form a water-soluble primer layer; a metal layer formation step of forming a metal layer consisting of a first metal layer covering the water-soluble primer layer and a second metal layer except the first metal layer by a physical vapor phase growth method; and a washing step of expressing electric-wave penetrability by removing the water-soluble primer layer and the first metal layer.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for producing a metallic decorative film. More specifically, the present invention relates to a method for producing a metallic decorative film that is not limited to a specific metal such as indium or tin that is likely to exhibit a sea island structure, has excellent reproducibility of the position and size of the gap between metals that serves as a transmission path for radio waves, and can easily produce a metallic decorative film with high radio wave transmittance by simply washing with environmentally friendly water without using an etching solution that is harmful to the environment as in a photolithography process. [Background technology]

[0002] Conventionally, metallic decorative films with radio wave permeability have been developed. In order to exhibit radio wave permeability, specific metals that are likely to exhibit a sea island structure are used. In response to this, methods that can use metals other than those that are likely to exhibit a sea island structure have also been considered. Patent Document 1 discloses that a crack-inducing layer and a metal film layer are provided on a base sheet, and a metal film decorative sheet having cracks is obtained by heating while pulling. Patent Document 2 also discloses a method for manufacturing a radio wave permeable cover that includes a transparent resin material that serves as an exposed portion, a decorative body that is disposed inside the transparent resin material, a resin substrate that serves as an attachment portion, and a metallic radio wave permeable layer that is disposed between the transparent resin material and the resin substrate, and a radio wave radar device is disposed on the back side, the method comprising the steps of preparing a laminate having a metal layer with a thickness of 60 nm or more and a crack-inducing layer that induces cracks in the metal layer, and a step of integrally molding the transparent resin material, the resin substrate, and the laminate, and forming the radio wave permeable layer by generating cracks in the metal layer at the temperature and pressure during integral molding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-5999 A [Patent Document 2] JP 2019-64100 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the manufacturing methods described in Patent Documents 1 and 2 are methods in which tension or the like is applied to the metal layer to generate cracks and thereby exhibit radio wave transparency, so that it is difficult to control the reproducibility of crack generation. In addition, since the toughness of metals varies depending on the type of metal, the manufacturing methods described in Patent Documents 1 and 2 require complex setting of conditions for generating cracks. As a result, the obtained metallic design has poor reproducibility. In addition, the metal layer after crack generation is likely to have a rough appearance. As a result, the obtained metallic decorative film is likely to have poor quality.

[0005] The present invention has been made in consideration of such conventional inventions, and aims to provide a method for producing a metallic decorative film that is not limited to specific metals such as indium and tin, which are likely to exhibit a sea island structure, and that, unlike production methods that cause cracks, has excellent reproducibility of the position and size of the gaps between metals that serve as radio wave transmission paths, and that can easily produce a metallic decorative film with high-quality radio wave transmittance by simply rinsing with environmentally friendly water without using an etching solution that is harmful to the environment, as in the photolithography process. [Means for solving the problem]

[0006] As a result of intensive research, the present inventors have found that the above-mentioned problems can be solved by forming a water-soluble primer layer of a predetermined pattern shape using a water-soluble primer composition, forming a metal layer thereon by physical vapor deposition, and then washing with water, and have completed the present invention. That is, the manufacturing method of the metallic tone decorative film of the present invention that solves the above-mentioned problems mainly includes the following configurations.

[0007] (1) A method for producing a metallic decorative film having radio wave transparency, comprising: a water-soluble primer layer forming step of applying a water-soluble primer composition onto a substrate along a predetermined pattern to form a water-soluble primer layer; a metal layer forming step of forming a metal layer consisting of a first metal layer covering the water-soluble primer layer and a second metal layer other than the first metal layer by physical vapor deposition; and a water washing step of removing the water-soluble primer layer and the first metal layer to exhibit radio wave transparency.

[0008] According to this configuration, the method for producing the metallic decorative film is not limited to specific metals such as indium and tin that tend to exhibit a sea island structure, and has excellent reproducibility of the position and size of the gaps between metals that serve as radio wave transmission paths. In addition, the method for producing the metallic decorative film can easily achieve high-quality radio wave transmission by simply washing with environmentally friendly water without using an etching solution that is harmful to the environment as in the photolithography process.

[0009] (2) The method for producing the metallic decorative film having radio wave transparency described in (1), wherein the substrate is composed of a base sheet and an anchor layer formed on the base sheet, and the method includes an anchor layer forming step of forming an anchor layer on the base sheet prior to the water-soluble primer layer forming step.

[0010] According to this configuration, the method for producing a metallic decorative film can further improve the adhesion between the substrate and the metal layer.

[0011] (3) The method for producing a radio wave transparent metallic decorative film according to (1) or (2), wherein the physical vapor deposition method is a deposition method.

[0012] According to this configuration, the method for producing the metallic decorative film has better productivity.

[0013] (4) The method for producing a radio wave transparent metallic decorative film according to (1) or (2), wherein the physical vapor deposition method is a sputtering method.

[0014] According to this configuration, the method for producing a metallic decorative film has superior film quality for the formed metal layer.

[0015] (5) The method for producing a radio wave transparent metallic decorative film according to any one of (1) to (4), wherein the metal layer contains aluminum.

[0016] According to this configuration, the method for producing a metallic decorative film has a metallic luster that is superior to that of the obtained metallic decorative film. Effect of the Invention

[0017] According to the present invention, a method for producing a metallic decorative film can be provided that is not limited to specific metals such as indium and tin, which are prone to exhibiting a sea island structure, and that has excellent reproducibility of the position and size of the gaps between metals that serve as radio wave transmission paths, and that can easily produce a metallic decorative film with high radio wave transmittance by simply rinsing with environmentally friendly water without using an etching solution that is harmful to the environment as in the photolithography process. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic cross-sectional view of a substrate prepared in a method for producing a metallic decorative film according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a state in which a water-soluble primer layer is formed by applying a water-soluble primer composition to a substrate and onto the substrate along a predetermined pattern shape in a manufacturing method of a metallic decorative film according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic cross-sectional view of a state in which a metal layer has been formed by physical vapor deposition in a method for producing a metallic decorative film according to one embodiment of the present invention. [Figure 4]FIG. 4 is a schematic cross-sectional view of a state in which the water-soluble primer layer and the first metal layer are removed by washing with water in a manufacturing method of a metallic decorative film according to one embodiment of the present invention, and a laminate (metallic decorative film) is formed in which the substrate and the second metal layer are laminated. [Diagram 5] FIG. 5 is a schematic plan view of a metallic decorative film according to one embodiment of the present invention. [Figure 6] FIG. 6 is a schematic plan view of a metallic decorative film according to one embodiment of the present invention. [Figure 7] FIG. 7 is a graph showing the measurement results of the electric field shielding property. [Figure 8] FIG. 8 is a graph showing the measurement results of the magnetic field shielding property. [Figure 9] FIG. 9 is a schematic diagram showing the equipment configuration of the KEC method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] <Metallic decorative film manufacturing method> The manufacturing method of the metallic decorative film (hereinafter, also referred to as film) according to one embodiment of the present invention includes a water-soluble primer layer forming step of applying a water-soluble primer composition on a substrate along a predetermined pattern shape to form a water-soluble primer layer, a metal layer forming step of forming a metal layer consisting of a first metal layer covering the water-soluble primer layer and a second metal layer other than the first metal layer by physical vapor deposition, and a water washing step of removing the water-soluble primer layer and the first metal layer to exhibit radio wave transparency. Each of these steps will be described below.

[0020] (Water-soluble primer layer formation process) The water-soluble primer layer forming step is a step of applying a water-soluble primer composition onto a substrate along a predetermined pattern shape to form a water-soluble primer layer. Figure 1 is a schematic cross-sectional view of a substrate 1 prepared in the method for producing a metallic decorative film of this embodiment.

[0021] ·Base material The substrate is not particularly limited. For example, the substrate may be made of a poly(meth)acrylic acid ester such as polymethyl methacrylate (PMMA), polycarbonate, polyethylene terephthalate, polyethylene-2,6-naphthalate, polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or the like.

[0022] The thickness of the substrate is not particularly limited. For example, the thickness of the substrate is preferably 4 μm or more, more preferably 10 μm or more. The thickness of the substrate is preferably 200 μm or less, more preferably 125 μm or less. When the thickness of the substrate is within the above range, the film has excellent scratch resistance and abrasion resistance.

[0023] The substrate may be subjected to a desired surface treatment. The surface treatment is not particularly limited. Examples of the surface treatment include matte treatment, satin treatment, embossing, hairline treatment, etc. In addition, the surface of the substrate (the surface opposite to the surface on which the anchor layer is formed) may be subjected to various types of coating (fluorine treatment, hard coat treatment, etc.), transfer treatment, etc. This can impart various designs and functions to the surface of the substrate.

[0024] The substrate may be subjected to various surface treatments. The surface treatment is not particularly limited. Examples of the surface treatment include corona treatment, plasma treatment, ion bombardment treatment, and ion implantation treatment. This can improve the adhesion of the substrate to a layer formed thereon.

[0025] The substrate may be a substrate on which an anchor layer is formed in order to improve adhesion with a metal layer described later. In this case, the substrate is composed of a substrate sheet made of the above-mentioned material and an anchor layer formed on the substrate sheet.

[0026] The anchor layer is not particularly limited. For example, the anchor layer may be made of a material that has good adhesion to the base sheet and good acceptability for the metal contained in the metal layer, such as an acrylic resin, a nitrocellulose resin, a polyurethane resin, a polyester resin, a styrene-maleic acid resin, or a chlorinated PP resin.

[0027] The thickness of the anchor layer is not particularly limited. For example, the thickness of the anchor layer is preferably 0.05 μm or more, more preferably 0.2 μm or more. The thickness of the anchor layer is preferably 10 μm or less, more preferably 2 μm or less. When the thickness of the anchor layer is within the above range, the film has excellent adhesion between the substrate and the metal layer.

[0028] The anchor layer may be provided with a design by adding a colorant or a metallic pigment. For example, by blending a yellow pigment as a colorant, the laminate film may have a golden appearance. The type and content of the colorant may be appropriately adjusted according to the desired metallic appearance. In addition, the anchor layer may be provided with functionality such as an antistatic effect by blending an antistatic agent or the like.

[0029] The method of forming the anchor layer is not particularly limited. For example, the anchor layer is formed by an anchor layer forming step of forming an anchor layer on a substrate sheet before a water-soluble primer layer forming step, and can be formed by screen printing, gravure printing, offset printing, flexographic printing, inkjet printing, blade coating, gravure offset coating, bar coating, roll coating, knife coating, air knife coating, comma coating, U comma coating, AKKU coating, smoothing coating, microgravure coating, reverse roll coating, four-roll coating, five-roll coating, dip coating, curtain coating, slide coating, die coating, spray coating, organic vapor deposition, CVD, etc.

[0030] The resin solution of the anchor layer is applied to the base sheet and then dried. This allows the surface of the base sheet to be soaked in the solvent of the resin solution, and the resin constituting the anchor layer and the base sheet become compatible with each other. As a result, a substrate in which the anchor layer and the base sheet are firmly attached to each other can be produced.

[0031] Water-soluble primer composition The water-soluble primer composition is a material for forming a water-soluble primer layer, and is a component that dissolves in water so that it can be removed by the water washing process described below. The water-soluble primer composition is not particularly limited. For example, the water-soluble primer composition is a polyvinyl resin-based paint (modified polyvinyl resin, amorphous silica, barium sulfate, methanol, isopropyl alcohol), a cellulose resin-based paint (cellulose resin, propylene glycol, calcium carbonate, silica, water), an ethylene glycol resin-based paint (ethylene glycol), etc.

[0032] FIG. 2 is a schematic cross-sectional view showing a substrate 1 and a water-soluble primer layer 2 formed by applying a water-soluble primer composition onto the substrate 1 along a predetermined pattern shape in the manufacturing method of the metallic decorative film of this embodiment.

[0033] The method of forming a water-soluble primer layer by applying a water-soluble primer composition along a predetermined pattern shape is not particularly limited. For example, the water-soluble primer composition may be applied to a substrate along a predetermined pattern shape by a screen printing method, a gravure printing method, an offset printing method, a flexographic printing method, or an inkjet printing method. In addition, the water-soluble primer composition may be applied to a substrate along a predetermined pattern shape by a blade coating method, a gravure offset coating method, a bar coating method, a roll coating method, a knife coating method, an air knife coating method, a comma coating method, a U comma coating method, an AKKU coating method, a smoothing coating method, a microgravure coating method, a reverse roll coating method, a four-roll coating method, a five-roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method, an organic deposition method, a CVD method, or the like. Thereafter, the applied water-soluble primer layer is appropriately dried to form a water-soluble primer layer of a predetermined pattern shape. In the film manufacturing method of this embodiment, a transmission path of radio waves is formed along a predetermined pattern shape by carrying out a metal layer forming step and a cleaning step described later. The position and size of the gap between the metals in such a transmission path of radio waves can be easily adjusted with excellent reproducibility in the water-soluble primer layer forming step.

[0034] The thickness of the water-soluble primer layer is not particularly limited. For example, the thickness of the water-soluble primer layer is preferably 0.5 μm or more, more preferably 1 μm or more. The thickness of the water-soluble primer layer is preferably 15 μm or less, more preferably 10 μm or less. By having the thickness of the water-soluble primer layer within the above range, the water-soluble primer layer is easily and appropriately removed by the water washing step described below.

[0035] ·Metal layer formation process The metal layer forming step is a step of forming a metal layer consisting of a first metal layer covering the water-soluble primer layer and a second metal layer other than the first metal layer by physical vapor deposition. In this embodiment, the first metal layer and the second metal layer are layers formed simultaneously by physical vapor deposition. The first metal layer and the second metal layer are distinguished from each other depending on the position where the metal layer is formed (on the substrate or on the water-soluble primer layer).

[0036] The physical vapor deposition (PVD) method is not particularly limited. Examples of the PVD method include deposition (resistance heating, high-frequency induction heating, electron beam heating, etc.), sputtering (magnetron, dual magnetron, facing targets, etc.), ion beam sputtering, ion beam deposition, ion plating, laser ablation, molecular beam epitaxy, cluster ion beam method, etc.

[0037] The type of metal constituting the metal layer is not particularly limited. For example, the type of metal is appropriately selected depending on the type of PVD method. Specifically, when the deposition method is used, the metal may be Al, Cu, Ag, Cr, Ni, In, Sn, Au, Pt, ZnS, SiO2, ZnS, TiO2, MgF2, or the like. When the sputtering method is used, the metal may be ITO, SiO2, Ag, Ag-Cu alloy, APC, Cu, Ni-Cr alloy, zinc-based oxide, or the like. Thus, the film manufacturing method of this embodiment is not limited to specific metals such as indium and tin that tend to exhibit a sea island structure, and various metals can be used. For example, the metal layer preferably contains aluminum. As a result, the film manufacturing method of this embodiment provides a film with a superior metallic luster.

[0038] In this embodiment, the physical vapor deposition is preferably a deposition method, and more preferably a deposition method using a high-frequency induction heating system, which provides the film production method of this embodiment with superior film productivity.

[0039] Fig. 3 is a schematic cross-sectional view of a state in which a metal layer 3 is formed by physical vapor deposition in the manufacturing method of the metallic decorative film of this embodiment. As shown in Fig. 3, the metal layer 3 is composed of a first metal layer 31 that covers the water-soluble primer layer 2, and a second metal layer 32 other than the first metal layer 31. Note that the first metal layer 31 is also formed slightly on the side surface of the water-soluble primer layer 2, but this is omitted in Fig. 3.

[0040] The thickness of the metal layer (first metal layer and second metal layer) is not particularly limited. For example, the thickness of the metal layer is preferably 5 nm or more, more preferably 10 nm or more. The thickness of the metal layer is preferably 1 μm or less, more preferably 0.5 μm or less. When the thickness of the metal layer is within the above range, the obtained film can realize various metallic patterns, and has better design and design. When the thickness of the metal layer is within the above range, the water-soluble primer layer and the first metal layer are easily removed in the water washing step described later.

[0041] ·Water washing process The water washing step is a step for removing the water-soluble primer layer and the first metal layer, thereby exhibiting radio wave transparency.

[0042] The water used in the water washing step is not particularly limited, and examples thereof include tap water, pure water (e.g., ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, etc.), and ultrapure water.

[0043] The water may contain additives such as surfactants as appropriate.

[0044] The washing method in the water washing step is not particularly limited. For example, the water washing step may be carried out by applying the above-mentioned water as running water to the laminate on which the substrate, the water-soluble primer layer and the metal layer are formed, or by immersing the laminate in a water tank containing water. This allows the water-soluble primer layer and the first metal layer to be removed. During or after washing with water, the laminate may be subjected to ultrasonic treatment of the substrate on which the printing and film are formed, or rubbing treatment with a sponge roll, as appropriate.

[0045] 4 is a schematic cross-sectional view of the state in which the water-soluble primer layer 2 and the first metal layer 31 (see FIG. 3) are removed by washing with water in the manufacturing method of the metallic decorative film of this embodiment, and a laminate (metallic decorative film 10) is formed in which the base material 1 and the second metal layer 32 are laminated. As shown in FIG. 4, the metallic decorative film 10 exhibits radio wave transparency due to the formation of a portion not covered by the metal layer.

[0046] In addition, such a water washing process is not only environmentally friendly, but also very easy to carry out, since it does not use an etching solution that is harmful to the environment, as in conventional photolithography processes. In addition, the resulting metallic decorative film has a metal layer (second metal layer) remaining along the specified pattern shape, and has high design reproducibility. Furthermore, the resulting film can exhibit high-quality radio wave transmittance.

[0047] <Metallic decorative film> The metallic decorative film (hereinafter also referred to as film) of one embodiment of the present invention comprises a substrate and a metal layer (second metal layer) formed on the substrate in a predetermined pattern shape, and has radio wave transparency.

[0048] Fig. 5 is a schematic plan view of the metallic decorative film 10a of this embodiment. Fig. 5 illustrates the metallic decorative film 10a with a striped pattern. As shown in Fig. 5, the metallic decorative film 10a is composed of an area A where a second metal layer is formed on a substrate, and an area B where the substrate is exposed. Area A shows a metallic design. On the other hand, area B shows radio wave transparency.

[0049] The width L1 of the region A is preferably 0.05 μm or more, more preferably 0.1 μm or more, and even more preferably 1 μm or more. The width L1 is preferably 1,000 μm or less, and more preferably 500 μm or less. By having the width L1 within the above range, the film has excellent metal design properties.

[0050] The width L2 of the region B is preferably 0.01 μm or more, more preferably 0.015 μm or more, and even more preferably 1 μm or more. The width L2 is preferably 1,000 μm or less, and more preferably 500 μm or less. When the width L2 is within the above range, the film has excellent radio wave transmittance.

[0051] The ratio (L1:L2) of the width L1 to the width L2 is preferably L1:L2=30:1 to 1:3, and more preferably 10:1 to 1:1. When the ratio (L1:L2) is within the above range, the film can achieve both better radio wave transparency and metal design.

[0052] Fig. 6 is a schematic plan view of the metallic decorative film 10b of this embodiment. Fig. 6 illustrates the metallic decorative film 10b in which a lattice pattern is formed. That is, the film has a plurality of second metal layers 32, each of which has a rectangular shape in a plan view, arranged in rows. The dimensions of each second metal layer 32 are a vertical width L3 and a horizontal width L4. The second metal layers 32 constituting adjacent rows are arranged so that their positions are shifted by half the length (L3 / 2) of the vertical width L3.

[0053] The vertical width L3 is preferably 0.05 μm or more, and more preferably 0.1 μm or more. The vertical width L3 is preferably 1,000 μm or less, and more preferably 500 μm or less. By having the vertical width L3 within the above range, the film has excellent metal design properties.

[0054] The width L4 is preferably 0.05 μm or more, and more preferably 0.1 μm or more. The width L4 is preferably 1,000 μm or less, and more preferably 500 μm or less. By having the width L4 within the above range, the film has excellent metal design properties.

[0055] The spacing (width L5) between the second metal layers constituting adjacent rows is preferably 0.01 μm or more, and more preferably 0.015 μm or more. The width L5 is preferably 1,000 μm or less, and more preferably 500 μm or less. By having the width L5 within the above range, the film has excellent radio wave transmittance.

[0056] The spacing (width L6) between the second metal layers constituting the same row is preferably 0.01 μm or more, and more preferably 0.015 μm or more. The width L6 is preferably 1,000 μm or less, and more preferably 500 μm or less. By having the width L6 within the above range, the film has excellent radio wave transmittance.

[0057] In the film of this embodiment, the structure (Sea island structure) as shown in Fig. 6 can be artificially produced by the above-mentioned film production method. Therefore, the types of metals that can be used in the film are not limited to specific metals such as indium and tin that tend to exhibit a Sea island structure, and various metals can be used. As a result, the film can exhibit excellent radio wave transmission and metal design properties even when, for example, a general-purpose metal is used.

[0058] In particular, when a lattice pattern shape as shown in Fig. 6 is adopted, the film has excellent three-dimensional formability, and therefore the film can be easily processed into a molded product (metallic molded product).

[0059] Specifically, the film may be provided with a separator. The film may be a separator with an adhesive layer provided in advance, or the film may be a separator with an adhesive layer formed thereon, and the adhesive layer may be attached to the metal vapor deposition layer so that the adhesive layer is in contact with the metal vapor deposition layer.

[0060] The separator is not particularly limited, and examples thereof include polyethylene terephthalate (PET), polyethylene, polypropylene, and plastic films or papers whose surfaces are coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent.

[0061] When the separator is peeled off, the adhesive layer is exposed. The exposed adhesive layer is attached to an adherend (described later) before molding.

[0062] (adherent) In the film of the present embodiment, an adherend (backing sheet, backer) may be provided on the adhesive layer. The adherend is preferably provided when a film insert method is adopted in manufacturing the metallic molded product described below. The adherend is not particularly limited. As an example, the adherend may be a thermoformable polymer sheet, and is preferably an ABS sheet, a polyacrylic sheet, a polypropylene sheet, a polyethylene sheet, a polycarbonate sheet, an A-PET sheet, a PET-G sheet, a polyvinyl chloride (PVC) sheet, a polyamide sheet, or the like.

[0063] The thickness of the adherend is not particularly limited. For example, the thickness of the adherend is preferably 0.05 to 5 mm, and more preferably 0.3 to 3 mm, from the viewpoint of moldability in compression molding or the like.

[0064] The adherend may be subjected to a desired surface treatment. The surface treatment is not particularly limited. Examples of the surface treatment include matte finish, satin finish, embossed finish, hairline finish, various patterns, and the like.

[0065] The adherend may have an adhesive layer already formed thereon, or an adhesive layer may be formed on the adherend, and the adherend may be attached so that the adhesive layer is in contact with the metal layer.

[0066] Thereafter, the adherend to which the film of the present embodiment is attached is appropriately processed into a three-dimensional shape to produce a metallic molded product. The molding method of the metallic molded product is not particularly limited. For example, the molding method is vacuum molding, TOM (Three Dimension Overlay Method) molding, etc. In TOM molding, the film is applied to a previously prepared adherend, and is softened by heat, so as to be integrally molded to conform to the adherend. On the other hand, in vacuum molding, the film is heated and softened by a heater. Next, the heated film is pressed against a mold having a desired three-dimensional shape while being vacuum-suctioned, and is deformed to conform to the shape of the three-dimensional molded product.

[0067] In this way, the metallic toned molded body is easily manufactured by molding. The above-mentioned film is used for the metallic toned molded body that is molded. Therefore, the metallic toned molded body can be given various designs. In addition, the metallic toned molded body exhibits radio wave transparency.

[0068] The metallic molded body is not particularly limited. For example, the metallic molded body is a metallic vehicle interior / exterior member, a metallic signboard, a metallic home appliance, a metallic amusement product, a metallic building material, etc. Among these, the metallic molded body is preferably used as a metallic vehicle interior / exterior member. The metallic vehicle interior / exterior member is not particularly limited. For example, the metallic vehicle interior / exterior member is an instrument panel garnish and ornament, an audio panel, an automatic air conditioner panel, a steering ornament, a door trim ornament, a power window switch bezel, an operation knob, various switches and caps or covers, a radiator grill, a pillar garnish, a back door ornament, a side mirror cover, an outer panel, a rear spoiler, an inside or outside door handle, a side visor, a wheel cover, a cowling for a two-wheeled vehicle, etc. Among these, the metallic vehicle interior / exterior member of the present embodiment is more preferably used in the front part of an electric vehicle (the grill part in an engine vehicle). That is, an electric vehicle does not need a grill in the front part of the vehicle. Furthermore, for the purposes of ADAS (Advanced Driver Assistance System) and autonomous driving technology, a millimeter wave radar is provided at the front of the vehicle. In such a case, the metallic molded body of the present embodiment is capable of transmitting millimeter waves, and therefore can conceal devices such as the millimeter wave radar while transmitting millimeter waves. As a result, the metallic molded body can be used in place of the grille portion and various designs can be adopted for the front of the electric vehicle without impairing the function of the millimeter wave radar. EXAMPLES

[0069] The present invention will be described in more detail below with reference to the following examples. The present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass".

[0070] <Example 1> A PET substrate (50 μm thick, U41 manufactured by Toray Industries, Inc.) was prepared, and a water-soluble primer layer was formed on the PET substrate in the striped shape shown in FIG. 5 using a water-soluble primer composition (TSM-397 manufactured by GOO Chemical Industry Co., Ltd., cellulose resin-based paint) and a screen printing plate manufactured by Nakanuma Art Screen Co., Ltd. (water-soluble primer layer forming step). The dimensions of the width X of the opening portion and the width Y of the non-opening portion of the striped screen printing plate manufactured by Nakanuma Art Screen Co., Ltd. were set to X / Y=45 μm / 90 μm. The thickness of the printed water-soluble primer layer was about 6 μm. The printed water-soluble primer composition oozed out slightly. Therefore, the width L2 of the printed striped water-soluble primer layer in the width direction was larger than 45 μm, which is the width A of the opening portion of the screen printing plate (the edge portion in the width direction was jagged, so the average was calculated to exceed 45 μm). After that, an aluminum layer was formed on the entire surface by vacuum deposition (metal layer forming step). The thickness of the aluminum layer was about 50 nm. Next, the obtained laminate was immersed in an ultrasonic water tank filled with tap water for 1 minute and subjected to a rubbing treatment with a sponge to remove the water-soluble primer layer and the aluminum layer (first metal layer) formed on the water-soluble primer layer, thereby obtaining a sample of Example 1.

[0071] <Comparative Example 1> A PET substrate (thickness 50 μm, U41 manufactured by Toray Industries, Inc.) was prepared, and an aluminum layer was formed on the entire surface of the PET substrate by vacuum deposition to obtain a sample of Comparative Example 1. The thickness of the aluminum layer was about 50 nm.

[0072] The metallic luster and electromagnetic wave shielding properties (electric field shielding properties and magnetic field shielding properties) were evaluated by the following methods using the samples obtained in Example 1 and Comparative Example 1. The results are shown in Figs. 7 and 8 and Tables 1 and 2.

[0073] (Metallic luster) The presence or absence of metallic luster was confirmed by visual inspection.

[0074] (Electromagnetic wave shielding) An electromagnetic shielding characteristic measuring system (N9000A, manufactured by Agilent Technologies) was used to evaluate the electric field shielding property and the magnetic field shielding property by the KEC method, with the measurement frequency range set to 100 kHz to 1 GHz. The KEC method is a method developed by the Kansai Electronics Industry Development Center, and can measure the magnetic field strength and the electric field strength in the near field (space close to the electromagnetic wave source). FIG. 9 is a schematic diagram showing the equipment configuration of the KEC method. As shown in FIG. 9, an electromagnetic wave of a predetermined frequency sent from a signal generator SG is transmitted through a sample (not shown) held by a jig J, and the intensity difference before and after the electromagnetic wave passes through the sample is measured. In FIG. 9, reference characters D, P, SA, and PC indicate an attenuator, a preamplifier, a spectrum analyzer, and a personal computer, respectively.

[0075] [Table 1]

[0076] [Table 2]

[0077] As shown in Tables 1 and 2, the sample (metallic decorative film) of Example 1 of the present invention had metallic luster, and also had electric field permeability and magnetic field permeability. FIG. 7 is a graph showing the measurement results of electric field shielding. FIG. 8 is a graph showing the measurement results of magnetic field shielding. As shown in FIG. 7 and FIG. 8, the sample (metallic decorative film) of Example 1 of the present invention did not have electric field shielding or magnetic field shielding, but had electric field permeability and magnetic field permeability. Thus, according to the manufacturing method of the metallic decorative film of the present invention, it is possible to easily form gaps between metals that serve as a transmission path for radio waves without being limited to specific metals such as indium and tin that tend to exhibit a sea island structure, and it was possible to easily obtain a film that can exhibit high-quality radio wave permeability by simply washing with environmentally friendly water without using an etching solution that is harmful to the environment as in the photolithography process. [Explanation of symbols]

[0078] 1 Base material 2 Water-soluble primer layer 3 metal layer 31 1st metal layer 32 Second metal layer 10, 10a, 10b Metallic decorative film A, B area SG Signal Generator D Attenuator J Jig L1, L2, L5, L6 width L3 Height L4 Width P Preamp PC SA Spectrum Analyzer

Claims

1. a water-soluble primer layer forming step of applying a water-soluble primer composition onto a substrate along a predetermined pattern shape to form a water-soluble primer layer; a metal layer forming step of forming a metal layer including a first metal layer covering the water-soluble primer layer and a second metal layer other than the first metal layer by physical vapor deposition; and a water washing step of removing the water-soluble primer layer and the first metal layer to thereby exhibit radio wave transparency.

2. The substrate includes a base sheet and an anchor layer formed on the base sheet, The method for producing a metallic decorative film having radio wave transparency according to claim 1, further comprising the step of forming an anchor layer on the base sheet prior to the step of forming the water-soluble primer layer.

3. The method for producing a radio wave transparent metallic decorative film according to claim 1 or 2, wherein the physical vapor deposition method is a deposition method.

4. The method for producing a metallic decorative film having radio wave transparency according to claim 1 or 2, wherein the physical vapor deposition method is a sputtering method.

5. The method for producing a radio wave transparent metallic decorative film according to claim 1 , wherein the metal layer contains aluminum.

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