JPH0362703A - Electromagnetic wave reflecting body - Google Patents

Abstract

PURPOSE:To obtain an electromagnetic wave reflecting body with less deterioration in the working performance due to winding kink and having excellent electromagnetic wave reflecting performance by integrating a cloth woven by wefts and warps one of which is a metallic wire and a nonmetallic wire and the other of which is a metallic wire into a synthetic resin. CONSTITUTION:A nonmetallic wire 12 and a metallic wire 14 are used for warps and a metallic wire 16 is used for wefts. The nonmetallic wire 12 and the metallic wire 14 are arranged in parallel and woven in crossing with the metallic wire 16 respectively. Various weaving methods such as plain weave or twill weave are applicable to woven structure of the wefts and warps. The diameter of the metallic wire of the wefts and warps is selected to be 50-300mum. The metallic wire-woven cloth formed in this way is cut out in a proper shape, laminated in a metallic die and subject to press forming integrally with a resin sheet, or suspended perpendicularly in a laterally open metallic die and integrated with a resin sheet with injection molding after closing die. If wefts are made up only of metallic wires, winding furrows are caused, cutting performance is deteriorated and it is impossible to suspend the close in the perpendicular direction.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to parabolic antennas for satellite broadcast reception and data facsimile transmission and reception, reflectors for radio wave absorbers to prevent radar interference and TV ghost prevention, and personal computers. , printers, etc. OA a, etc. EM I
(electromagnetic 1nterf
erence) relates to an electromagnetic wave reflector used for shielding.

[Conventional technology]

As these electromagnetic wave reflectors, in addition to using metal plates themselves, metal foil and backup resin, wire mesh and bank-up resin, conductive non-woven fabric and backup resin, conductive paint, Zn spraying and backup resin, etc. are used. be. Various manufacturing methods are being considered for each application from the viewpoint of shape or economy.

In particular, when a wire mesh is used as an electromagnetic wave reflecting material, the weaving density of the metal wire can be changed depending on the target shielding frequency. It is generally said that this weaving density needs to be A/4 or higher (Utility Model Application No. 17615/1983), but especially in the case of parabolic reflectors for satellite broadcast reception, the reflection loss is 0.3 dB.
Based on this, the present inventors have already proposed the necessary wire diameter and density (Japanese Patent Laid-Open No. 61
No. 212904).

In addition, in order to improve workability, we would like to present a woven fabric that is a blend of metal wire and non-metal wire.
issue).

It goes without saying that the wire mesh used as an electromagnetic wave reflector (1) has excellent electromagnetic wave reflection performance, but it also needs to be lightweight and have excellent workability such as formability, impregnability, and cuttability. It is.

However, in the case of a general filter wire mesh, when the wire diameter is 100 μm, the weaving density (wires/25 mm, hereinafter the same) is 715 ~
The fibers are as small as 120, and have poor resin impregnation properties, and the oil used during weaving needs to be degreased with trichlene or the like, resulting in high costs. Further, if the wire diameter exceeds 200 μm, the cutting properties are poor, and although the weave density can be made somewhat coarse (20 to 65 wires), the weight is heavy and the wire tends to curl, making it difficult to handle.

In addition, when using a wire mesh as a reflective material for microwaves at 8 to 20 GHz, the wire diameter and density (wires/25 mm) are 50 to 90 μm, and the density (120 to 80 wires, preferably 30 to 50 wires). When the wire diameter is 90 to 130 μm, the density is 15 to 60, preferably 20 to 50,
When the wire diameter is 130 to 170 μm, the density is 10 to 45 wires, preferably 20 to 40 wires, which is R) 1'4, which provides a good balance of reproducibility, formability, workability, cost, etc. JP-A No. 61212904). However, wire meshes in these ranges are difficult to manufacture, and looms are also limited. In addition, even if the wire diameter and density of the metal wire are set in this way, if metal wire is used for all the warp and weft threads, it will be difficult to mold a fabric with curls, especially if you try to return it to a flat shape. Removal becomes insufficient.

In addition, all warp and weft threads are
Using a blended yarn of metal wire and non-metal wire as described in No. 9 and JP-A No. 61-212904 improves workability, but the material cost and manufacturing cost of the yarn itself increases, and the resin Impregnation increases the contact resistance between metal wires,
Electromagnetic wave reflection performance may deteriorate.

[Problem to be solved by the invention]

In consideration of the above facts, the present invention is equivalent to obtaining an opposite body to the electromagnetic 21 using an electromagnetic wave reflector that is flexible, does not reduce workability due to curling curls, and has good electromagnetic wave reflection performance.

[Means for resolving slavery issues]

The present invention is an electromagnetic wave reflector in which a cloth material woven with warp and weft is integrated with a synthetic resin, and in the heavy phase, one of the warp and weft is a metal wire or a non-metal wire, and the other is a metal wire or a non-metal wire. It is characterized by being made of metal wire.

In addition, in the present invention, the metal wires of the warp and weft have a wire diameter of 50
The thickness can be from μm to 300 μm.

By using a non-metallic wire in combination with a metal wire for only one of the warp or weft threads, we have created a reflective material that is highly flexible, has almost no winding curls, has no winding creases, is low-cost, and has good electromagnetic wave reflection performance. It becomes possible to form a woven fabric. Out of all the warps or wefts forming the woven fabric before cutting, at least 115 or more warps or wefts, more preferably 1/3 or more warps or wefts are cut from the combination of non-metallic wires and metal wires or flexible. desirable for security. Further, as a method of combining them, a method of aligning one or more non-metallic wires and one or more metal wires, or a configuration in which these are twisted together in advance is possible. Alternatively, the metal wires and the non-metal wires may not be combined, but the non-metal wires may be arranged at appropriate intervals on the warp or cotton yarn.

The metal wire-containing woven fabric created in this way is either cut into an appropriate shape and laminated in a mold and press-molded integrally with the resin sheet, or it is hung vertically in a side-opening mold.
It is possible to integrate it with the resin by injection molding after the mold is closed. If the warp direction is made of only metal wires, winding wrinkles will occur, the cuttability will be poor, and it will be impossible to hang vertically.

The metal wires used for the warp and weft include brass, copper, stainless steel, galvanized iron, aluminum, etc., but brass is preferable in consideration of workability, cuttability, and cost. These metal wires may be formed from a single strand, or may be formed by twisting several strands together to form a single metal wire. The wire diameter of the metal wire is 5
0 to 300 μm is good, more preferably 100 to 17
0 μm is good. If the thickness is less than 50 μm, the weaving density of the metal wire must be io wires/25 mm or more for radio wave reflection performance, which increases the number of manufacturing steps for the woven fabric and increases the cost.

Furthermore, if the thickness exceeds 300 μm, the strength of the metal wire increases and it becomes difficult to weave a woven fabric. The weaving density of the metal wires is appropriately selected from 10 to 80 wires depending on the desired frequency, which is effective in terms of performance. The wire diameters and weaving density of the warp and weft can be changed depending on the radio wave resistance performance, formability, dimensional stability, strength, etc.

Both organic and inorganic materials can be used as the non-metallic wire, including fibers such as polynisdel, vinylon, polyamide, polyethylene, polypropylene, cellulose, hemp, glass, carbon, twine, fiber bundle, spun yarn, or blends thereof. String etc. are effective.

[Embodiments of the invention]

FIG. 1A shows a woven structure of an electromagnetic wave reflecting material for an electromagnetic wave reflector according to a first embodiment of the present invention.

A non-metal wire 12 and a metal wire 14 are used as the warp, and a metal wire 16 is used as the weft. Non-metal wire 12 and metal wire 14
are arranged parallel to each other, and the metal wires 16
It has a woven structure that intersects with each other.

Various weaving methods such as plain weave and twill weave can be applied to this weaving structure of the warp and weft, and this point also applies to the following modified examples.

Referring next to FIG. 1B, a second embodiment of the present invention is shown.

In this embodiment, the number of non-metallic wires 12 in the warp yarns in the first embodiment is smaller than the number of metal wires 14, and they are thinned out.

FIG. 2A shows a woven structure in which metallic wires 14 are pretwisted around non-metallic wires 12. According to this, the metal wire 14 is reliably twisted with the non-metal wire 12, so weaving is ensured, but the contact point between the metal wire 14 and the metal wire 16 is different from the weaving structure of the first embodiment. Therefore, there is a possibility that the reflection performance will be less favorable than that of the electromagnetic wave reflecting material of the first embodiment.

Further, in the fourth embodiment shown in FIG. 2B, the number of non-metallic wires 12 in the third embodiment is thinned out and reduced. Naturally, the metal wires 14 in the areas where the non-metallic wires 12 are thinned out are untwisted, as in FIG. 1B.

In the fifth embodiment shown in FIG.
A state in which the metal wires 14 and 14 are alternately implanted at equal intervals is shown.

FIG. 4 shows an example of a parabolic antenna 20 to which these woven structures are applied. In this parabolic antenna 20, an electromagnetic wave reflector 22 is sandwiched between a back-up layer 24 and a surface layer 26, the back-amp layer 24 and the surface layer 26 are integrally formed, and the whole is bent into a parabolic shape. ing.

The back-up layer 24 and the surface layer 26 can be made of synthetic resin reinforced with glass fibers, and the surface layer 26 can be made by painting or in-mold coating, or by using non-woven fabric or woven fabric made of glass or polyester yarn, or resin-impregnated fabric. The bristle gunte may be laminated and integrated with the reflective material and the resin for the back-up layer.

The resin for the back-up layer may be either a fiber-reinforced synthetic resin or a non-reinforced synthetic resin, and a thermosetting or thermoplastic resin may be selected as appropriate.

In this way, the warp threads of the electromagnetic wave reflector 22 include a mixture of metal wires 14 and non-metal wires 12, so even if the wires are bundled into a roll after being manufactured and stored, the warp threads of the electromagnetic wave reflector 22 will not curl if they are straightened during molding. The problem is resolved and molding work can be started immediately.

In the above embodiment, a metal wire and a non-metallic wire are used for the warp threads, and a metal wire is used for the weft threads, but it is also possible to use a metal wire and a non-metallic wire for the weft threads.

Furthermore, if misalignment or cuts occur during molding, the surface of the woven fabric may be treated with an acrylic, polyester, epoxy, poval, or the like binder.

In FIGS. 1A to 3 in the above embodiment, the warp and weft are shown arranged with a large interval, but
Needless to say, these can be closely interwoven.

Experimental example (1) As a woven fabric of electromagnetic wave reflecting material, one brass wire with a wire diameter of 1000 μm and one glass fiber: T, It East were aligned in the warp direction and the first fabric was made with a density of 20 wires/25 mm.
It was arranged as shown in Figure A. One brass wire with a wire diameter of 150 μm was inserted into the weft at a density of 24 wires/25 mm.

This reflection+;I woven fabric and a sheet molding compound (SMC
) and glass cloth (100 g/m') as a surface layer were laminated in a mold and heat compression molded. The molding conditions were a mold temperature of 140° C., a mold clamping pressure of 50 kg/cnt, and a hold time of 4 minutes to obtain a molded product with a thickness of 3 mm. The electromagnetic wave reflection coefficient of the obtained molded product is 12 Gllz, 0.96 in the warp direction, and 1? A good parabolic antenna with a thread direction of 0.97 was molded.

(2) 1 with a wire diameter of 100 μm in the warp direction as a reflective woven fabric
Twist together one brass wire and one glass fiber bundle, 28
They were arranged as shown in Fig. 2Δ with an implantation density of 1/25 mm. One brass wire with a wire diameter of 1.50 μm is used for the weft.
It was implanted at a density of 4 pieces/25 m+n.

This reflective woven fabric was molded with SMC in the same manner as in (1). The electromagnetic wave reflection coefficient of the obtained molded product was 0985 in the warp and weft directions, making it a good parabolic antenna molded product.
In the case of the 45 type reflector, the gain was as high as 34 dB.

In addition, when the present invention is applied to the reflector for a parabolic antenna of the above embodiment, in particular, when the short axis of the reflecting surface is 90 cm.
When used in a large parabolic antenna with a diameter of m or more, the warp direction using a non-metal is a reinforcing rib that is generally provided on the back side of such a reflector for a parabolic antenna, especially one that extends in the long axis (up and down) direction. It is preferable to make the direction substantially coincident with the direction of the existing reinforcing ribs in order to ensure Rb surface accuracy of the reflective surface.

〔Effect of the invention〕

Since the present invention has the above configuration, it is possible to obtain an inexpensive electromagnetic wave reflecting material that has excellent electromagnetic wave reflecting performance, is highly flexible, and is resistant to curling. In addition, there are no cracks or cuts when integrally formed with a resin, and the resin is highly impregnated, making it possible to obtain an electromagnetic wave reflector with excellent surface appearance and weather resistance.

[Brief explanation of drawings]

Fig. 1Δ is an enlarged plan view showing the woven structure of the electromagnetic wave reflecting material for an electromagnetic wave reflector according to the first embodiment of the present invention, and Fig. 1B is an enlarged plan view showing the woven structure according to the second embodiment. Eight flashes are the third
An enlarged plan view showing the weaving structure △ according to the example, FIG. 2B is an enlarged plan view showing the weaving structure according to the fourth example, and FIG. 3 shows the weaving structure according to the fifth example. Enlarged plan view, Figure 4 is a longitudinal sectional view showing an example of an electromagnetic wave reflector to which the present invention is applied. 12... Non-metal wire, 14. 16... Metal wire, 20... Parabola Antenna, 22... Electromagnetic wave reflector, 24... Backup layer, 26... Surface layer.

Claims (2)

[Claims] (1) An electromagnetic wave reflector in which a cloth material woven with warp and weft threads is integrated with a synthetic resin, wherein one of the warp threads and weft threads is a metal wire or a non-metallic wire, and the other is a metal wire. An electromagnetic wave reflector characterized by being a line. (2) The warp and weft metal wires have a wire diameter of 50 μm to 3
The electromagnetic wave reflector according to claim 1, wherein the electromagnetic wave reflector has a diameter of 00 μm.