JPH0739230B2 - Conductive transfer sheet - Google Patents

Description

Detailed Description of the Invention

 Purpose of the invention

[Industrial applications]

The object of the present invention is to improve an electroconductive transfer sheet used for imparting electroconductivity to the surface of a molded article such as plastic, ceramic or glass.

[Prior art]

For example, as a means of imparting conductivity to the surface of a plastic molded product, a conductive transfer sheet that has a metal deposition layer on a releasable base film is used, and the metal deposition layer is transferred to the surface of the molded product. There is a way to do it. However, when the metal vapor deposition layer is transferred to the surface of a molded article using this transfer sheet, the metal vapor deposition layer has no ductility, and thus cracks are likely to occur. As a means for forming a circuit pattern on the surface of a molded article, similarly to the above, a metal vapor deposition layer and an etching resist layer are provided in this order on a releasable substrate film, and a circuit pattern is formed by etching, There is a method of transferring a circuit pattern using a transfer sheet. In this case as well, there is the same problem as above. Also, since there is an etching step, this technique is costly.

[Problems to be Solved by the Invention]

It is an object of the present invention to improve the above-mentioned conventional technique to form a surface or a circuit pattern having sufficient conductivity on the surface of a molded article such as plastic, which has a high surface corrosion resistance, at a low cost. An object of the present invention is to provide a conductive transfer sheet that enables Structure of the invention

[Means for solving problems]

In one and basic embodiment of the present invention, as shown in FIG. 1, a conductive transfer sheet 1A comprises a releasable base material film 11, a conductive material vapor deposition layer 12, and a conductive material. An ink layer 13 and an adhesive layer (not shown) are provided on the entire surface in this order, and the conductive material vapor deposition layer is a layer of two or more layers of different metals or conductive compounds, and the surface after transfer. Is a conductive transfer sheet for a plastic molded product, in which the layer exposed at is nickel, chromium or tin. In the modified embodiment of the present invention, as shown in FIG. 2, the conductive transfer sheet 1B is formed by forming the conductive ink layer 13 according to the circuit pattern. A mode in which the vapor deposition layer is etched into a circuit pattern and then a conductive ink layer is formed on the circuit pattern is also possible. The material of the releasable substrate film may be a single or laminated film of plastic such as polyester, polyamide, polyvinyl chloride, polyethylene, polypropylene, polycarbonate, polyimide, polyetherimide, polysulfone, cellulose acetate, polyarylate. . Needless to say, the releasability does not need to be particularly taken into consideration as long as the base film itself has releasability.
When it has no releasability as it is, a release layer is provided for use. The release layer is roll coated using a thermoplastic resin such as polyvinyl chloride, acrylic resin, polyamide, nitrocellulose, polyvinyl acetate, polyester, polyvinyl butyral, or a thermosetting resin such as melamine, phenol or polyurethane. Method, gravure printing method, silk screen printing method, dipping method, spraying method, or any other method. The release layer includes a type that remains on the substrate film side after transfer and a type that moves to the vapor deposition layer side. If it is moved to the vapor deposition layer side, it can also serve as a protective layer. that time,
The release layer is not printed at the place where conduction is maintained. The deposited layer of conductive material is aluminum, tin, zinc,
Metals and alloys such as copper, silver, gold, nickel, chromium, titanium, cobalt, selenium and molybdenum, or tin oxide,
A metal compound such as indium oxide, barium titanate, titanium oxide, zinc sulfide, or tungsten oxide may be used as a material and may be formed by any means such as a vacuum deposition method, a sputtering method, or an ion plating method. The conductive ink is prepared by kneading powder of metal such as gold, palladium, silver, nickel, copper or carbon powder with a binder. The binder is mainly composed of a synthetic resin, which is a thermosetting resin such as phenol, epoxy or amino resin, and polyolefin, polyester, vinyl chloride-vinyl acetate copolymer, polyamide, acrylic resin, polyvinyl butyral. From thermoplastic resins such as
Select an appropriate one and use it. The application is arbitrary such as silk screen printing, gravure printing or offset printing. Adhesive is polyester, polyamide, acrylic resin,
Roll coating method, gravure printing using thermoplastic resin such as vinyl chloride-vinyl acetate copolymer, nitrocellulose, ethylene-vinyl acetate copolymer, polyimide, polyvinyl butyral, or thermosetting resin such as epoxy or polyurethane. Method, silk screen printing method or any other method. To explain the method of using the transfer sheet of the present invention, in a typical example, the transfer sheet 1B shown in FIG. 2 is placed in injection molds 2A and 2B as shown in FIG. Injection molding of synthetic resin is performed. Take out the molded product and base film
When 11 is peeled off, the vapor deposition layer 12 of the conductive material in the portion where the conductive ink layer 13 is not present has a weak adhesiveness with the molded product, and thus is removed on the side of the releasable base material film, as shown in FIG. ,
A circuit pattern including a conductive ink layer 13 and a conductive material vapor deposition layer 12 is formed on the surface of the molded product 3. Similarly, when the transfer sheet 1A is used, a conductive ink layer and a conductive material vapor deposition layer are formed in this order on the entire surface of the molded product. As another usage, transfer sheet 1A (1B) on the surface of the molded product
It is also possible to transfer the material by placing it on it and heating and pressing it.

[Work]

When the transfer sheet of the present invention is used to transfer to the surface of a molded article such as plastic, a molded article having a conductive ink layer under a vapor deposition layer of a conductive substance can be obtained. Even if a crack occurs in the vapor-deposited layer of a conductive substance during transfer, the conductive ink layer covers it and sufficient conductivity can be secured.
The adhesive layer ensures the adhesion of the conductive ink layer to the molded part. This effect is particularly useful when the plastic molded product has a deeply drawn curved surface. By using nickel, chromium, or tin as the layer that appears on the surface after transfer out of the two vapor-deposited layers, it is possible to provide desirable properties such as corrosion resistance by utilizing their physical and chemical stability. In the embodiment in which the conductive ink layer is formed according to the circuit pattern, the circuit pattern can be formed without etching.

Example 1 A melamine resin was coated on the entire surface of a 75 μm thick polyetherimide film by gravure printing to obtain a releasable base film. On this releasable substrate film, tin, copper and nickel were vacuum-deposited in this order. A conductive ink obtained by kneading a binder containing a vinyl chloride-vinyl acetate copolymer as a main component and copper powder, on the above metal vapor deposition layer,
A desired circuit pattern was printed by a silk screen printing method and dried. An acrylic resin adhesive was printed on the above conductive ink layer by a silk screen method and dried. The obtained conductive transfer sheet was placed in an injection molding die to perform injection molding of polycarbonate, a molded product was taken out, and the releasable base material film was peeled off. The metal vapor deposition layer in the portion without the conductive ink layer was removed, and a circuit pattern composed of the conductive ink layer and the metal vapor deposition layer was formed on the surface of the molded product. The resistance value of this circuit pattern was 0.05Ω / □.

Example 2 A 50 μm-thick polyester film was coated with a melamine resin to form a releasable base film, and tin and copper were vacuum-deposited in this order on the base film. A conductive ink obtained by kneading a binder containing a polyester resin as a main component and nickel powder was applied on the entire surface of the metal vapor deposition layer by silk screen printing and dried. Next, in the same manner as in Example 1, an adhesive layer was formed on the above conductive ink layer. The surface of the adhesive layer of the obtained conductive transfer sheet was placed on a molded article of ABS resin and transferred by heating and pressing, and a conductive ink layer and a metal deposition layer were formed on the entire surface of the molded article. It was The resistance value of the surface of this ABS resin molded product was 0.1 Ω / □. EFFECTS OF THE INVENTION By using the conductive transfer sheet of the present invention, it is possible to impart high conductivity to the surface of a molded article such as plastic, which has sufficient electromagnetic wave shielding performance as well as antistatic property. When a transfer sheet having a conductive ink layer formed according to a circuit pattern is used, a molded product having a desired circuit pattern on its surface can be manufactured at low cost.

[Brief description of drawings]

1 and 2 are schematic cross-sectional views each showing the structure of the conductive transfer sheet of the present invention. FIG. 3 shows the conductive transfer sheet shown in FIG. 2 placed in an injection mold. FIG. 4 is a cross-sectional view of a molded product having a circuit pattern manufactured as shown in FIG. 1A, 1B …… Transfer sheet 11 …… Releasable base film 12 …… Electric vapor deposition layer 13 …… Conductive ink layer 2A, 2B …… Injection mold 3 …… Molded product

Claims (2)

[Claims] 1. A vapor-deposition layer of a conductive substance, a conductive ink layer and an adhesive layer are provided in this order on a releasable substrate film, and the vapor-deposition layer of the conductive substance is made of a different metal or conductive material. A conductive transfer sheet for a plastic molded article, which comprises two or more layers of a conductive compound, and the layer exposed on the surface after transfer is nickel, chromium or tin. 2. The conductive transfer sheet according to claim 1, wherein the conductive ink layer and the adhesive layer are formed according to a circuit pattern.