JPS59184597A - Electromagnetic wave reflector - 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 novel electromagnetic wave reflecting object.

Conventionally, metal plates (copper, aluminum, iron, permalloy, etc.) have generally been used as electromagnetic wave reflectors. Although this metal plate has a high electromagnetic wave reflectance and is excellent, it is expensive and has problems in terms of weight.Furthermore, it has drawbacks in terms of rust prevention, salt damage resistance, deformation resistance, etc. be. In actual use, a plastic surface coating is applied to prevent rust and salt damage, but in this case, the plastic layer easily peels off, so it is necessary to periodically apply this plastic coating, which requires a lot of effort. The problem is that it costs a lot of money.

On the other hand, as electromagnetic wave reflecting materials in place of metal plates, materials whose surfaces are coated with conductive paint and materials containing wire mesh, metal fibers, metallized glass fibers, carbon fibers, etc. in plastic have been proposed. All of these materials have problems in terms of durability, electromagnetic wave reflection characteristics, moldability, light weight, etc., and have not yet been put into practical use.

As a result of various research into the development of electromagnetic reflective materials to replace metal plates, the inventors of the present invention have developed a composite of plastics and filler-containing plastics with sheet materials made of conductive polymer fibers as electromagnetic reflective surfaces. It has an electromagnetic reflectance equivalent to that of a metal plate, has excellent rust prevention and salt damage resistance, is lightweight and easy to carry, and has mechanical strength and
They discovered that it also has excellent weather resistance and completed the present invention.

That is, according to the present invention, the electromagnetic wave reflecting material is substantially entirely made of plastic or filler-containing plastic, and a sheet-like material made of conductive polymer fiber is composited inside or on the surface of the material. Provided is an electromagnetic wave reflecting object characterized in that the proboscis-like shape of the sheet is made into an electromagnetic wave reflecting surface. In this specification, the electromagnetic wave reflecting object refers to various conventionally known shaped objects used to reflect electromagnetic waves, such as parabolic antennas for microwaves, reflectors for parasitic relays, and electromagnetic wrappers. , bass length lenses, etc.

The conductive polymer fibers used in the present invention are conventionally known, and are made by bonding a conductive metal or metal compound to the surface of polymer fibers such as acrylonitrile fibers, polyester, polyamide, etc. so that the entire body exhibits conductivity. Commercially available products such as r Thunderon,
5S-NJ (trade name, manufactured by Nihon Kasuke Dyeing Co., Ltd.), etc. can be used. In the present invention, specific resistance (unit: Ω
Polymeric conductive fibers having a diameter of about 1 or less, preferably 10 or less are generally used.

In the present invention, this polymeric conductive fiber is used to form a sheet-like material, and this is composited with plastic as an electromagnetic reflective surface. In this case, the C I-like object is
In addition to cloth-like products formed by knitting or weaving monofilaments of polymeric conductive fibers or twisted plural fibers thereof, nonwoven fabrics formed using short polymeric conductive fibers are included.

Furthermore, when used as a woven or knitted fabric, it is not necessary that all the warp and weft threads be made of polymer conductive fibers, and only one of the warp threads and weft threads may be made of polymer conductive fibers. In addition, the diameter of the warp and weft in woven or knitted fabrics is 0.1 to 3 mm, preferably 0.1 to 2 mm.
It is.

The sheet-like material made of conductive polymer fibers used in the present invention has a mesh-like void formed by mutual fibers,
In this case, the distance d between the polymer conductive fibers forming the void (the distance between the centers of two fibers separated in parallel) is equal to the wavelength of the target electromagnetic wave. When λ, d/λ should be 0.25 or less. In the case of the present invention, considering the compatibility with various electromagnetic waves, the distance d between the fibers is usually 0.25 as d/λ.
Below, it is preferable to set it to 0.1 to 0.01.

31 As the plastic material used in the present invention, various conventionally known thermoplastic resins, thermosetting resins, room temperature curable resins (cured with a curing accelerator), etc. can be used. This plastic also contains conventional additives such as talc, silica, alumina, and charcoal.
Fillers (including reinforcing agents) such as calcium, calcium sulfite, glass fibers, carbon fibers, carbon flakes, asbestos fibers, and gypsum can be contained. Preferred plastic materials used in the present invention include fiber reinforced plastics, such as
Fiber-reinforced unsaturated polyester resin (F'RP) can be mentioned.

There are various methods for producing the electromagnetic wave reflecting material of the present invention. For example, a sheet-like material made of conductive polymer fibers (hereinafter simply referred to as a sheet-like material) is held in a molten resin, and the material is cooled and solidified. Method.

A method in which a sheet-like object is held in a liquid resin and cured at room temperature or while heating in the presence of a curing accelerator, and two pre-formed plastic molded products are bonded together with an adhesive with a sheet-like object interposed between them. 4- In addition to methods such as attaching a sheet to the surface of the plastic molded product, there is also a method of laminating and adhering a sheet-like material to the surface of the plastic molded product and, if necessary, coating the top with plastic. Any method can be used as long as it is capable of compositing a sheet-like material made of conductive polymer fibers inside or on the surface of a plastic molded product.

In the present invention, when polymer conductive fibers are composited with plastic in sheet form as described above, curved products such as parabolic antennas are created because polymer conductive fibers are highly flexible. It has the great advantage that it is extremely easy to process, and curved products with excellent surface precision can be easily obtained. Moreover, the adhesion of polymeric conductive fibers to plastics is good;
Furthermore, since the resin or adhesive penetrates into the voids between the fibers, the bonding force of the sheet made of conductive polymer fibers to the plastic becomes extremely strong, and the plastic and conductive polymer fibers become strong and bonded. An integrated composite product can be obtained.

Examples of cross-sectional structures of the electromagnetic wave reflecting material of the present invention are shown in FIGS. 1 to 3.

Figure 1 shows a sheet material made of conductive polymer fibers inserted into liquid or molten plastic, and then cured as a whole, with reference numeral 1 being plastic and 3 being made of conductive polymer fibers. A sheet-like product is shown. In this case, the plastic 1 is integrally connected to the sheet-like material 3 through the gap.

In Figure 2, a sheet-like material 3 made of polymeric conductive fiber is interposed between plastics 1 and 2.
It has a structure in which the surfaces are bonded together with an adhesive.

In FIG. 3, a sheet-like material 3 made of conductive polymeric fibers is adhered to the surface of a plastic 1 with an adhesive, and the surface is coated with plastic to form a plastic coating layer 4.

Since the electromagnetic wave reflecting object of the present invention is substantially composed entirely of plastic or filler-containing plastic, it is lightweight and convenient to carry, is inexpensive, and has good weather resistance and durability. It also has excellent mechanical strength. Furthermore, the electromagnetic wave reflecting object of the present invention has electromagnetic wave reflecting performance equivalent to that of a metal plate, and is essentially different from conventional metal plates in terms of directivity and phase characteristics required for an electromagnetic wave reflecting object. It never happens.

FIG. 4 shows the frequency 70 of the parabolic antenna according to the present invention.
FIG. 3 shows a graph of the gain characteristics for 0.00 MHz in relation to the diameter of the parabolic antenna. The parabolic antenna in this case has the cross-sectional structure shown in Figure 1, and the sheet material 3 made of polymeric conductive fibers has an average specific resistance of 5. .85 x 10 r Thunderon, 5
S-NJ (manufactured by Nippon Joke Dyeing Co., Ltd., trade name) was used for the woven fabric (tight, mesh, spacing 5 mm), and as the plastic material, fiber-reinforced unsaturated polyester resin (FRP) was used. .

As is clear from the graph shown in FIG. 4, it is clear that the product of the present invention has excellent electromagnetic reflection performance.

In addition, in the case of a conventional parabolic antenna made of a metal plate (aluminum plate), the gain at diameters of 0.3 m, 0.6 m, and 1.2 m is 2 at 7000 MHz, respectively.
3 dB, 29 dB and 35 dB.

7-

[Brief explanation of drawings]

Figures 1 to 3 are detailed explanatory views of the present invention. Figure 1 is an example in which a sheet-like material made of polymeric conductive fibers is composited into a single piece of plastic, and Figure 2 is a An example in which a sheet-like material made of conductive polymer fibers is bonded to the laminated surface of two plastic laminates using an adhesive. Examples are shown in which the plastic coating layer 4 is provided on the surface of the composite. FIG. 4 is a graph showing the gain of the invention (parabolic antenna) in relation to its diameter. Patent Applicant: Nippon Satsuki Dyeing Co., Ltd. (2 idiots) Agent: Patent Attorney Toshiaki Ikeura 8- Figure 1 Figure 2 Figure 6 Figure 4 Frequency 7000 MH2 Procedure Amendment Book May 16, 1982 Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office■, Indication of the case, Patent Application No. 5971.1 of 1982, Name of the invention, Electromagnetic Wave Reflector 3, Person making the amendment, Relationship with the case Patent Applicant Address: Kyoto, Kyoto Prefecture 35 Butai-cho, Fushimi-ku, City Name
Japan Silk Hair Dyeing Co., Ltd. (and 2 others), Representative Shinji Tomibe 4, Agent 151 Address 1-58-10-5 Yoyogi, Shibuya-ku, Tokyo.
Date of amendment order: 6, Number of inventions increased by amendment: 0 7, Subject of amendment: Detailed explanation of the invention in the specification, column 8
, Contents of the amendment The following amendments will be made in the specification of the application. (1) Change the [requirements of conductive fibers] on page 4, line 7 to “
Correct it to ``need'' to make it a conductive fiber. (2) Page 8, line 13, “Nit, mesh, interval 5m
m) J, mesh spacing 0.5mm)
Correct to J.

Claims (1)

[Claims] (1) The electromagnetic wave reflecting object is substantially entirely composed of plastic or filler-containing plastic, and
An electromagnetic wave reflecting object characterized in that a sheet-like material made of conductive polymer fiber is composited inside or on the surface thereof, and the sheet-like material serves as an electromagnetic wave reflecting surface.