JPH0358558B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a conductive thermoplastic resin chip used for shielding electromagnetic waves, and particularly a method for manufacturing the conductive thermoplastic resin chip for shielding electromagnetic waves efficiently, that is, at low cost. It is related to.

In Western countries, the housing of electronic devices such as computers, word processors, etc. is It is mandatory to use a device that has been treated to shield electromagnetic waves emitted by the electronic device.

The aforementioned electromagnetic shielding of electronic equipment is becoming mandatory in Japan sooner or later, and various electromagnetic shielding methods are being considered.

Shielding of electromagnetic waves like this can basically be achieved by imparting appropriate conductivity to the housing that covers the electronic device, so a fibrous conductive material is added to the thermoplastic resin that makes up the housing. Methods of electromagnetic shielding in which the housing itself is electrically conductive are also well known.

When manufacturing such conductive resin molded products,
It is common to use a chip mixed with a fibrous conductive material and mold it into a predetermined shape.

The conductive thermoplastic resin chip for shielding electromagnetic waves as described above is conventionally made by inserting a fibrous conductive material, for example, metal fiber 2, into a molten thermoplastic resin 1, as shown in FIG. A conductive thermoplastic resin chip for shielding electromagnetic waves was manufactured by forming a thermoplastic resin layer 3 on the surface and cutting the linear body in the transverse direction.

However, according to this method of manufacturing conductive thermoplastic resin chips for shielding electromagnetic waves, only one linear body for manufacturing conductive thermoplastic resin chips for shielding electromagnetic waves can be manufactured at a time, which is extremely difficult. The drawback was that it was inefficient and therefore costly.

The present invention has been made in view of the above points,
To provide a method for efficiently and inexpensively manufacturing the electromagnetic wave shielding conductive thermoplastic resin chip by manufacturing a plurality of linear bodies of the thermoplastic resin-coated fibrous conductive material as described above at once. With the goal.

Therefore, the method for producing conductive thermoplastic resin chips for shielding electromagnetic waves according to the present invention involves arranging a plurality of fibrous conductive materials at predetermined intervals in a plurality of rows in the longitudinal direction of a thermoplastic resin film or sheet, and then applying the thermoplastic resin Thermoplastic resin films or sheets of the same quality as the film or sheet are laminated by heat and pressure bonding, cooled, and then longitudinally cut between the rows of the fibrous conductive material to produce a linear body covered with thermoplastic resin. The present invention is characterized in that the linear body is formed into a chip shape by cutting the linear body in the transverse direction.

According to the method of manufacturing a conductive thermoplastic resin chip for shielding electromagnetic waves according to the present invention, fibrous conductive material is placed on a thermoplastic resin film or sheet at predetermined intervals, and this is covered with a thermoplastic resin film or seal. After cooling and hardening, it is possible to produce multiple linear bodies of thermoplastic resin-coated fibrous conductive material at once by cutting the gaps between the laid metal fibers, which is faster than conventional methods. This method has the advantage that a large amount of conductive thermoplastic resin chips for shielding electromagnetic waves can be manufactured at one time.

The present invention will be explained in more detail.

In the present invention, first, a thermoplastic resin film or sheet is prepared.

The thermoplastic resin used in the present invention is basically not limited, and resins conventionally used for housings of electronic devices of this type can be effectively used. For example, it can be a film or sheet made of one or more resins such as polypropylene resin, ABS resin, modified PPO resin, polyamide resin, polycarbonate resin, and PPS resin.

A plurality of rows of tow-like fibrous conductive materials are laid down at predetermined intervals on such a film or sheet.

Such fibrous conductive materials are not fundamentally limited in the present invention. Any fiber may be used as long as it has conductivity. For example, metal fibers made of iron, iron alloys such as stainless steel, aluminum, aluminum alloys, copper, copper alloys, etc., or carbon fibers such as polyacrylonitrile-based, pitch-based, rayon-based, etc. can be used. A thermoplastic resin of the same quality as the thermoplastic resin film or sheet is laminated on the film or sheet in which the fibrous conductive material is placed by heat and pressure, and then cooled.

The reason why the thermoplastic resin of the same quality as the thermoplastic resin on which the fibrous conductive material is laid is laminated is because the adhesive properties of both thermoplastic resins are taken into consideration.

By cooling in this manner, the films or sheets are bonded to each other and integrated.

The fibrous conductive material of the thus formed laminated film or sheet is cut in the longitudinal direction between a plurality of rows laid out in the longitudinal direction. By cutting in this manner, a linear body containing the fibrous conductive material inside can be formed.

By cutting this linear body into a predetermined size in the transverse direction, a large amount of conductive thermoplastic resin chips for shielding electromagnetic waves can be manufactured in large quantities.

Next, examples of the present invention will be described.

2 and 3 are schematic diagrams of an apparatus for implementing an embodiment of the manufacturing method according to the present invention,
In the figure, 22 and 24 are thermoplastic resin films or sheets, 25 is a hot pressure bonding roll, 27 is a fibrous conductive material, 29 is a laminated film or sheet, 2
00 is a cooling roll, 210 is a serrated roll, 220
230 is a cutter, and 240 is a conductive thermoplastic resin chip for shielding electromagnetic waves.

A bottom thermoplastic resin film or sheet 22 wound around a storage roll 21 and a top thermoplastic film or sheet 24 in a semi-molten state just extruded from an extruder 23 are bonded together by a hot pressure bonding roll 25.

At this time, the fibrous conductive materials 27, 27, 27... wound around the plurality of rolls 26, 26, 26... are arranged at predetermined intervals in the length direction of the film or sheet.
It is placed on the bottom thermoplastic resin film or sheet 22.

Layout of this fibrous conductive material 27, 27, 27... and thermoplastic resin film or sheet 22
The bonding with 24 and 24 is performed, for example, as shown in FIG. That is, roll 26,2
Fibrous conductive material 27, 27, from 6, 26...
27, . . . are placed on the bottom thermoplastic resin film or sheet 22 in the length direction at predetermined intervals by comb teeth 28. In this way, the fibrous conductive material 2
After forming rows 7, 27, 27... at predetermined intervals, a top film or sheet 24 is laminated,
Bonding is carried out using a hot pressure bonding roll 25.

The laminated film or sheet 29 bonded in this way is guided to a cooling roll 200 and cooled by the cooling roll 200 to harden the thermoplastic resin film or sheet 24, and the thermoplastic resin film or sheet 22 and the fibrous conductive Material 27,2
7, 27, . . . and the top thermoplastic resin film or sheet 24 are integrated.

The thus integrated laminated film or sheet 29 passes through a serrated roll 210. The serrated roll 210 has serrated sharp protrusions 2 on the surface of the roll.
11 and the upper roll 210a
and the protrusion 211 of the lower roll 210b are designed to interlock with each other, and this protrusion 211
is placed between the rows of fibrous conductive materials 27, 27, 27..., the rows of fibrous conductive materials 27, 27, 27... are separated from each other, and the fibrous conductive materials 27, 27, 27... are separated from each other. A linear body containing 27 can be formed.

When it is not possible to cut between the rows with the serrated rolls 210, a cutter 220 may be provided to cut along the grooves formed by the serrated rolls 211. In any case, the fibrous conductive material 27, 27, 27
By cutting in the longitudinal direction between the rows, a linear body containing a fibrous conductive material can be manufactured.

In this way, the linear body is cut into a predetermined length in the width direction using the cutter 230 to obtain a conductive thermoplastic resin chip 240 for shielding electromagnetic waves.

As explained above, according to the method for manufacturing conductive thermoplastic resin chips for shielding electromagnetic waves according to the present invention, compared to the conventional method for manufacturing conductive thermoplastic resin chips for shielding electromagnetic waves, multiple chips can be manufactured in one process. Since it is possible to manufacture a linear body containing fibrous conductive material,
This method has the advantage that a large amount of conductive thermoplastic resin chips for shielding electromagnetic waves can be manufactured quickly and the cost can be reduced.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a conventional apparatus for producing conductive thermoplastic resin chips for shielding electromagnetic waves, and Fig. 2 shows an embodiment of the method for producing conductive thermoplastic resin chips for shielding electromagnetic waves according to the present invention. FIG. 3 is an enlarged view of the part of the apparatus shown in FIG. 2 where the fibrous conductive material is laid down. 22... Thermoplastic resin film or sheet (bottom), 24... Thermoplastic film or sheet (top), 27... Fibrous conductive material, 28
... Comb tooth, 200 ... Cooling roll, 210 ... Giza roll.

Claims (1)

[Claims] 1. A plurality of rows of fibrous conductive materials are arranged at predetermined intervals in the longitudinal direction of a thermoplastic resin film or sheet, and then a thermoplastic resin film or sheet of the same quality as the thermoplastic resin film or sheet is heated. After laminating by crimping and cooling, the fibrous conductive material is cut in the longitudinal direction between the rows to form a linear body covered with a thermoplastic resin, and the linear body is cut in the transverse direction. 1. A method for producing conductive thermoplastic resin chips for shielding electromagnetic waves, the method comprising: forming a conductive thermoplastic resin chip into a chip shape. 2. A method for manufacturing a conductive thermoplastic resin chip for shielding electromagnetic waves according to claim 1, wherein the cutting in the longitudinal direction is performed in a step including means using a serrated roll.