JPH10270892A - Material and body for electromagnetic shielding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a radio-wave shielding body which makes use of the characteristic of a cork by a method wherein a cork base material is mixed with a metal fiber and a heated and compression-bonded sheetlike or boardlike radio- wave shielding body is molded to be a desire shaped. SOLUTION: When a radio-wave shielding material is manufactured, a cork blank is first prepared, it is crushed to small pieces in a size of about 3 to 10 mm while humidity is being kept at 3% or lower, and a base material 1 is formed. On the other hand, a stainless steel fiber 2 which is formed to be a thickness of about 2 to 50 μm is prepared, and the stainless steel fiber 2 is fixed uniformly so as to become a volume of about 0.5 to 1.0% of the volume of the base material 1. Then, this mixture is housed in a mold, it is heated while a pressure is being applied. Then, it is plastically deformed due to a bonding force by a resinlike composition by a cork itself, and a radio-wave shielding material (body) 6 is molded. The radio-wave shielding material (body) 6 has the characteristic and the outward appearance of the cork, it is excellent in a physical property and a mechanical property, and it does not contaminate an environment even after it is thrown away.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight electromagnetic wave shielding material, and more particularly, to a heat insulating property, a soundproof property, and a waterproof property suitable for preventing electromagnetic waves radiated from various electric devices from radiating outside. Also, the present invention relates to a lightweight electromagnetic shielding material and an electromagnetic shielding material excellent in oil resistance and the like.

[0002]

2. Description of the Related Art Conventionally, various products have been developed and used as lightweight shielding materials for preventing radiation of electromagnetic waves radiated from various electric devices to the outside. For example, in a base of a general-purpose plastic, there is, for example, a metal filament such as copper or a mesh or the like constituted by the filament embedded therein, but because the general-purpose plastic used is lipophilic. However, there are drawbacks that they are easily stained by an oil agent or the like and that the soundproofness is insufficient.

On the other hand, cork, which is the outer bark of cork oak, is composed of an aggregate of independent tetrahedral cells ( ² to 40 million cells in 1 cm ² ) containing countless very small air. In addition to being excellent in water resistance and soundproofing, it is extremely lightweight and buoyant, and has excellent compressibility and elasticity. Since it has various characteristics, such as a small number, it is used for various purposes such as houses, automobiles, electricity, aircraft, and more recently, an elastic material of a reactor containment and an outer wall surface of a space shuttle.

[0004] In recent years, in which environmental problems are highlighted, in various fields, a review for using natural materials instead of petroleum products has been made.
Therefore, the present inventor described above, as a result of variously examining plastic alternatives for the electromagnetic shield using a general-purpose plastic, particularly when cork is used as a base material,
The present inventors have found that this is an extremely good electromagnetic shielding material having excellent design properties, and arrived at the present invention.

[0005]

SUMMARY OF THE INVENTION Accordingly, it is a first object of the present invention to provide an electromagnetic shielding material or an electromagnetic shielding material utilizing the characteristics of cork. A second object of the present invention is to
An object of the present invention is to provide an electromagnetic shielding material and an electromagnetic shielding material which are excellent in heat insulating property, soundproofing and vibration-proofing property and are lightweight. Further, a third object of the present invention is to provide an electromagnetic shielding material or an electromagnetic shielding material which is excellent in antifouling property and hardly deteriorates over time, and is excellent in design.

[0006]

SUMMARY OF THE INVENTION The above objects of the present invention are attained by mixing a cork base material and a metal fiber, heating and compressing the mixture into a sheet-like or plate-like electromagnetic shielding material, and forming the material into a desired shape. This was achieved by an electromagnetic shield.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The cork base material used in the present invention includes virgin cork, waste from cork collection, waste from plugs, shavings (cork waist) generated during the production of cork products, and recovery after use. Any of cork and the like may be used, and these may be used alone or in combination. In use, it is preferable to use a lump of 3 to 10 mm, but a lump of a larger lump or a smaller lump can be used.

[0008] The metal fibers to be mixed with the cork base material are as follows:
There is no particular limitation as long as it can shield electromagnetic waves, but from the viewpoints of durability, weight, price, and the like, stainless steel fibers are particularly preferable, and SUS304 or SUS316L is particularly preferable. The thickness of the fiber is 2
The length is preferably about 50 μm, and the length is 10 mm or less, preferably 5 mm or less from the viewpoint of uniform mixing. Such a metal fiber does not necessarily have to be a single fiber. Even if it is not a single fiber, it is sufficient if it can be mixed substantially uniformly.

The mixing ratio between the cork base material and the metal fibers is about 0.3 to 2.0%, preferably 0.5 to 1.0%, by volume. In the present invention, to the extent that the performance as an electromagnetic shielding material is not impaired, it is also possible to add a dye / pigment or other additives, and to enhance the adhesion between the cork base materials or between the cork base material and the metal fiber. Agents and the like can also be added.

Next, the method of the electromagnetic shielding material of the present invention will be described in detail. FIG. 1 is an explanatory view showing an example of a method of manufacturing an electromagnetic shielding plate of the present invention, FIG. 2 is an explanatory view showing an example of a method of manufacturing an electromagnetic shielding sheet of the present invention, and FIG. It is a perspective view of a shielding plate. In the figure, reference numeral 1 denotes a substrate made of cork powder or cork granules, the size of which is about 3 to 10 mm. 2 is a stainless steel fiber mixed with the substrate 1. Reference numeral 3 denotes a uniform mixture of the substrate 1 and the stainless steel fiber 2, 4 denotes a mold, 5 denotes a heated roll, and 6 denotes an electromagnetic shielding plate of the present invention. Note that, in this specification, “electromagnetic shielding material” refers to a plate-shaped or sheet-shaped electromagnetic shielding material that can be appropriately cut or joined and used, and “electromagnetic shielding body” refers to a component outside an electric device. Various kinds of products having a specific shape such as a housing are collectively referred to.

In order to manufacture the electromagnetic shielding material of the present invention, first, a cork material is prepared, and while keeping the humidity at 3% or less, a cork material is prepared.
The substrate 1 is crushed to a size of about 10 to 10 mm. In this case, if a high-quality cork base material is used, the quality of the product naturally increases.

On the other hand, SUS304 or SUS316
A stainless steel fiber 2 made of a material such as L and having a thickness of about 2 to 50 μm is prepared, and the stainless steel fiber 2 is made to have a capacity of about 0.5 to 1.0% of the capacity of the base material 1. Fiber 2
Is uniformly mixed with the substrate 1. Then, this mixture 3 is
When housed in a mold 4 formed in a desired shape and heated while applying pressure, it is molded by the adhesive force of the resinous composition of the cork itself and formed into an electromagnetic shielding material (body) 6 having a desired shape. Is done. At this time, an adhesive may be added to the mixture 3 as needed.

At the time of manufacture, a mold is formed in accordance with the shape of the outer casing of the various electric devices, and the mixture is put in the mold and pressurized and heated to obtain a desired mold. An outer casing having a shape and having an electromagnetic shielding effect can be integrally formed. In the case of producing a long electromagnetic shielding sheet or plate, it is also possible to use a heating roll, insert the mixture between two rotating rolls, heat compress it, and continuously mold it ( (See FIG. 2).

The electromagnetic shielding material of the present invention has a compressibility, a tension and a thermal conductivity of 20%, 0.8 MPa and 0.0 MPa, respectively.
It is about 50 and has good soundproofness, water resistance, oil resistance, durability, chemical resistance, etc. and is nonflammable. In addition, the appearance has a characteristic of cork, and has a beautiful design.

[0015]

EXAMPLES Next, examples of the electromagnetic shielding sheet of the present invention will be described, but the present invention is not limited thereto.
The base material 1 made of cork having a particle size of about 3 to 10 mm
A mixture was prepared by mixing stainless steel fibers 2 of US316L stainless steel having a fiber diameter of 15 μm and a length of about 5 mm with respect to the base material 1 so as to be 0.7% by volume.
Next, the mixture was placed in a mold, and heated to 200 ° C. while applying a pressure of 100 kg / cm ³ to produce an electromagnetic shielding plate having a thickness of 3 cm. This electromagnetic shielding plate cleared both the electric field strength and the magnetic field strength at 40 MHz at 500 MHz.

[0016]

As described above, the electromagnetic shielding material (body) of the present invention has cork characteristics and appearance, is excellent in physical and mechanical properties, and pollutes the environment after disposal. Therefore, it is extremely effective as a new electromagnetic shielding material.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a manufacturing process of an electromagnetic shielding material of the present invention.

FIG. 2 is an explanatory view showing an example of a method for producing the electromagnetic shielding sheet of the present invention.

FIG. 3 is a perspective view of an electromagnetic shielding material manufactured according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Steel fiber 3 Mixture 4 Die 5 Hot-press roll 6 Electromagnetic shielding material (body)

Claims (4)

[Claims] 1. A sheet-shaped or plate-shaped electromagnetic shielding material obtained by mixing a cork base material and a metal fiber and heating them by compression. 2. The sheet-shaped or plate-shaped electromagnetic shielding material according to claim 1, wherein the metal fiber is a stainless steel fiber. 3. An electromagnetic shield formed by mixing a cork base material and a metal fiber, and compressing and heating to form a desired shape. 4. The electromagnetic shield according to claim 3, wherein the metal fiber is a stainless steel fiber.