JPH0427030B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin molded article having electrical conductivity.

In this specification, the term "thermally activated adhesive" means that when a dried adhesive layer interposed between a pair of objects to be bonded is heated, the adhesive layer becomes activated, that is, softens and melts, and becomes sticky again. means an adhesive with properties.

Conventionally, synthetic resin molded products having a conductive layer include a conductive sheet made of thermoplastic resin containing a conductive metal,
A laminated material consisting of a thermoplastic resin substrate heat-sealed thereto is thermoformed into a desired shape by air pressure forming or vacuum forming under heating. However, the thermoplastic resin sheet constituting the above-mentioned laminate contains a large amount of conductive metal flakes or short metal fibers, and some of these metal flakes or short metal fibers become entangled with each other to form lumps. Since these particles were scattered within the sheet, the conductive sheet had poor thermoformability. In addition, since the sheet and the substrate are integrated by heat fusion, the conductive sheet stretches to follow the stretching of the substrate during thermoforming, resulting in poor thermoformability as described above. The molded product broke at the stretched portion, resulting in a blemish that damaged the appearance of the molded product.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method for manufacturing a conductive synthetic resin molded article that can solve all of the above-mentioned problems.

The method for manufacturing a molded product according to the present invention includes the steps of: molding a laminate consisting of a conductive sheet made of thermoplastic resin and a substrate made of thermoplastic resin superimposed on the sheet into a desired shape under heating; A coating layer made of a heat-activated adhesive is interposed between the sheet and the substrate beforehand, and the laminated material connects the sheet and the substrate so that air can escape between them. Alternatively, the air may be forcibly removed and the coating layer may be bonded under heating with the coating layer. The laminated material may be formed by bonding the sheet and the substrate together under pressure and heat using a coating layer of the adhesive.

Typical examples of thermoplastic resins constituting the conductive sheet and the substrate, respectively, include vinyl chloride-based, acrylic-based, and acrylonitrile-butadiene-styrene-based resins.

Heat-activated adhesives include chloroprene rubber-based, nitrile rubber-based, and acrylic-based adhesives, and the coating layer is activated, that is, softened and melted at the thermoforming temperature of the conductive sheet and substrate, and becomes sticky again. The one that carries it is used.

Conductive sheets made of thermoplastic resin usually have a thickness of
It is 0.5 to 3.0 mm and includes metal flakes, short metal fibers, short glass fibers whose surface is coated with metal, mica flakes, etc.

Thermoplastic resin substrates are usually 1.0 to 5.0 mm thick.
belongs to.

Heat-activated adhesives are applied to the inside surface of a conductive sheet or substrate, typically in a thickness ranging from 10 to 500 microns.

Hereinafter, the present invention will be specifically explained with reference to embodiments shown in the drawings.

Example 1 100 parts by weight of polyvinyl chloride resin, tin-based stabilizer 3
1.5 parts by weight, extruded from a formulation consisting of 5 parts by weight of processing aid and 100 parts by weight of short copper fibers.
A conductive sheet with a thickness of 4.0 mm and a substrate with a thickness of 4.0 mm extruded from a compound consisting of three components of the above composition other than short copper fibers were prepared. A heat-activated adhesive (manufactured by Konishi Co., Ltd., trade name "Bond G19") was applied to a thickness of 30 μm on one side of the substrate and dried.

Next, as shown in FIG. 1A, a substrate 4 with the adhesive coating layer 3 facing up is placed between the pair of upper and lower clamps 1 and 2 of the molding machine, and a conductive layer is placed on top of the substrate 4 in an overlapping manner. A sheet 5 is arranged, a breathable member 6 is interposed between the substrate 4 and the conductive sheet 5 at the peripheral edge,
The substrate 4, sheet 5, and breathable member 6 are clamped 1,
Fixed at 2. Examples of the breathable member include a plate-like member 8 having ventilation grooves 7 on the lower surface as shown in FIG. 2A, a plate-like member 10 having ventilation holes 9 as shown in FIG.
There were a net-like material 11 as shown in FIG.

Next, as shown in FIG.
3, the conductive sheet 5 was heated for 40 seconds, and the lower heater 14 was used to heat the substrate 4 for 50 seconds (170° C.) to soften them. As a result, the conductive sheet 5 extends slightly more than the substrate 4 and overlaps the substrate 4 with the adhesive coating layer 3 in a softened and molten state interposed therebetween, and the air between them escapes through the breathable member 6. Ta. In this way, the laminated material 15 in a softened state was formed.

Next, the laminated material 15 in a heated and softened state is
As shown in FIG. After cooling and demolding, a molded article 17 was obtained. Further, as shown in FIG.
8 to obtain a molded product 19.

No breakage was observed in the conductive sheet portions of these molded products 17 and 19. Further, the sheet portion and the substrate portion were completely integrated by the adhesive force of the heat-activated adhesive after cooling.

Example 2 A laminate in which a conductive sheet and a substrate were bonded together under pressure and heat with a coating layer of adhesive was used (the conductive sheet, substrate, and adhesive were the same as in Example 1). (This is the same as the one used.) This laminated material was also pressure-formed or vacuum-formed to obtain a container-shaped molded product.

The molded product was also completely free of fractures.
Furthermore, the adhesion between the sheet part and the substrate part was perfect.

Example 3 As a breathable member of a molding machine, one having the structure shown in FIG. 3 was used. This breathable member 20 has a rectangular frame shape, and is made up of four rectangular tube-shaped frame members 21 and four T-shaped connecting members 22 that connect them.
One frame member 21 has a plurality of suction holes 23 on the inside and a connecting pipe 24 on the outside. This air permeable member 20 has a fitting portion 22a of the connecting member 22.
It can be easily disassembled by applying force to the protrusion 22b so that it comes out from the inside of the cylinder of the frame member 21.

As shown in FIGS. 1A and 1B, the substrate 4 is heated and softened by the same operation as in Example 1, and
Air between the conductive sheet 5 and the substrate 4 was forcibly extracted through the breathable member 20. In this way, the laminated material 15 in a softened state was formed, and a container-shaped molded product was manufactured from the laminated material 15 in the same manner as in Example 1.

In the case of this embodiment, since the air between the conductive sheet 5 and the substrate 4 is forcibly removed, the air can be removed reliably, and since the breathable member 20 can be assembled and disassembled freely, it is easy to take out the molded product. I was able to do it.

As described above, according to the method for manufacturing a synthetic resin molded product of the present invention, a coating layer made of a heat-activated adhesive is interposed between the conductive sheet and the substrate constituting the laminate before molding. By molding the laminated material in a heat-softened state, the adhesive coating layer can be softened and melted during molding to make it sticky. Therefore, the conductive sheet can extend independently at the bent portion of the molded article without following the stretching of the substrate, and therefore, the sheet will not break at the bent portion at all. In addition, since the conductive sheet and the substrate are bonded together by allowing the air between them to escape or by forcibly removing the air, there is no remaining air layer or bubble between them. . In this way, according to the manufacturing method of the present invention, a molded product with good appearance can be obtained.

[Brief explanation of drawings]

Figure 1 A, B, C, and D are vertical sectional views showing the manufacturing process of an embodiment of the present invention, Figure 2 A, B, C, and D are side views showing the breathable member, and Figure 3 is an embodiment. 3 is a perspective view showing the breathable member used in Example 3. FIG. 1, 2... Upper and lower clamps, 3... Adhesive coating layer, 4... Substrate, 5... Conductive sheet, 6... Air permeable member, 13, 14... Upper and lower heaters, 15...
Laminated material, 16... Air pressure forming machine, 18... Vacuum forming machine, 17, 19... Molded product, 20... Breathable member, 21... Frame member, 22... Connection member, 23...
...Suction hole, 24...Connection pipe.

Claims (1)

[Scope of Claims] 1. When molding a laminate consisting of a conductive sheet made of thermoplastic resin and a substrate made of thermoplastic resin superimposed on the sheet into a desired shape under heating, before molding, A coating layer made of a heat-activated adhesive is interposed between the sheet and the substrate, and the laminated material connects the sheet and the substrate in such a way that the air between them can escape or the same air can escape. 1. A method for producing a synthetic resin molded article having electrical conductivity, the method comprising: forcibly removing the molded article and adhering it with the coating layer under heating. 2. The method according to claim 1, wherein the laminated material is formed by bonding the sheet and the substrate together under pressure and heat using a coating layer of the adhesive.