JPS5914699A - Heat shrinkable plastic mold for magnetic shield - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic molded body having a magnetic shielding effect and having a magnetic shielding effect as a heat-shrinkable member.

Recently, polyethylene, ethylene vinyl acetate copolymer,
When manufacturing sheets, films, or thin sleeve-shaped molded products from plastics such as ethylene acrylic acid copolymer, ethylene chloride inzam, and ethylene propylene terpolymer, the molecules are aligned in a certain direction by stretching electron beam irradiation, etc. Materials that have been given contractility due to the memory effect have been used for a variety of purposes, including electrical insulators, and many improvements have been proposed, but to date, nothing that has a magnetic shielding effect has appeared. Not yet.

By the way, electrical and magnetic shielding is becoming increasingly necessary due to the miniaturization 1 rationalization of equipment, performance stability, close placement, etc. Until now, pure iron, permalloy, ferrite sintered shielding, etc. Solid plates are used, and ribbons of these materials are used for special electron tubes and cables, and only the essential parts of the circuit can be shielded.
For example, it is preferable because it can achieve the purpose of fca shielding, which impairs the characteristics of a small and light circuit.

The heat-shrinkable glass molded article for magnetic shielding of the present invention was created to solve this purpose, and is made of polyethylene, ethylene vinyl acetate copolymer, ethylene acrylic acid copolymer, ethylene zolopyrene rubber, etc. polymer,
A thin film, sheet or tube is made from a composition containing 1007+ (if part) of glasstic 1007+ (if part mixed with 0 to 95 calorific weight At this time, in the production of films or sheets, the film is stretched by the method of producing a uniaxially or biaxially stretched film, and in the production of tubes, it is expanded at the point where it exits the head during extrusion. Or, later, by increasing the internal pressure with a fluid and expanding it, or,
A short tube-shaped heat-shrinkable molded product or a cap-shaped heat-shrinkable molded product can be produced by injection molding in the same manner as described above.

The structure of the f'L fc molded product obtained according to the present invention is as shown in Fig. 1 (a ferrite plastic film stretched in the XX direction, or as shown in Fig. 2, expanded to a diameter of 70,000 times).
It is shown as a plastic tube filled with industrial light.

In this way, if the molded object is a film like that shown in Figure 1 (-), then place the film 1 around the area that requires shielding as shown in Figure 1 (o) so that the XX direction is tubular. Wrap horizontally and heat A tJ: A material that can be shrunk in the housing direction to tightly cover the main parts of the interior, and that requires shielding when the molded product is a tube 2 as shown in Figure 2. can be inserted into this and heat-shrinked to tightly cover the inside.Also, when the molded body is a cap-shaped body 3 as shown in FIG. It can be fitted and heat-shrinked, or it can be used in conjunction with the tube 2 of FIG. 2 and fitted onto its ends to achieve complete shielding.

This □ structure is much easier to work with than the conventional method of cutting out a ferrite sintered body and molding it to fit the dimensions of the product, which requires internal shielding. Shielding can be achieved.

As an example of the molded product of the present invention, a tube with an inner diameter of 10 mm and a thickness of 2III+ is made from a composition made of ethylene propylene rubber with addition of 7-elite, zinc steriophosphate, and an antioxidant.P1: After crosslinking the tube A tube metal having an inner diameter of 15 mm was obtained by stretching in the radial direction. This was heat-shrinked onto a 12-inch iron bar, and its magnetic permeability and other properties were measured.

For comparison, a sample containing no ferrite is also shown. Further, this tube has a heat shrinkage rate of about 20%.

As can be seen from the table above, the molded product using the ferrite additive of the present invention has excellent magnetic permeability, which varies depending on the type of ferrite, in addition to heat shrinkability, and the amount of 7E2 added to the resin On the other hand, a range of 10 to 95 Judo X is a preferable range from the viewpoint of processability and other physical properties. That is, if the ferrite content is less than 10% by weight, the magnetic permeability is insufficient, and if it exceeds 951% by weight,
It becomes too hard and is difficult to handle in practice.

Either or both of the outer bottom surfaces are coated with an insulating coating to prevent the heat-shrinkable ferrite layer from peeling off, or to provide shielding depending on the shape of the product. Of course, it is possible to mold it into an irregular shape other than that shown in the drawings as appropriate.

[Brief explanation of the drawing]

Figure 1 shows the case of a film among the molded articles of the present invention (a)
2 is a perspective view of the expanded state, (B) is a cross-sectional view of the rolled state, FIG. 2 is a perspective view of the tubular body, and FIG. 3 is a perspective view of the cap-like body. (1) Film (2) Pipe body (3) Cap-shaped body Agent Patent attorney Mamoru Takeuchi

Claims (1)

[Scope of Claims] <1> Heat-shrinkable plastic molding for magnetic shielding, characterized in that it consists of a thin layer that is made of a composition made by adding and blending ferrite powder into plastic and is given heat-shrinkability. body. (2) The blending amount of ferrite powder is 10 to 95% by weight
A heat-shrinkable glass molded article for magnetic shielding according to claim 1.