JPH0452109A - Production of reflecting mirror for parabolic antenna - Google Patents

Abstract

PURPOSE:To raise productive efficiency and to enhance receiving characteristics by previously coating a film with electrically-conductive coating and weather resistant coating and inserting the film thus prepared into a mold and injection-molding resin. CONSTITUTION:Nylon cloth 14 is applied with a wax-based peeling agent 13 and dried. Thereafter this nylon cloth 14 is applied with fluororesin-based weather resistant coating 12 and dried. Furthermore this coated weather resistant coating 12 is printed with electrically-conductive paste 11 wherein 40 parts medium is kneaded with 60 parts copper powder. Thereafter the said paste 11 is dried and hardened at 80 deg.C in an oven. After this printed material 10 is provided so that the cloth side is placed on the face of a mold and the film coated with copper is placed on the inner face of a reflecting mirror, resin is injection-molded. After this resin is solidified, a molded form is taken out and the nylon cloth 14 is peeled. The layer 11 coated with copper and the layer 12 coated with weather resistant coating are transferred on the molded form, namely on the inner face of the reflecting mirror. A parabolic antenna is completed by applying final coating on the reflecting mirror produced by the above-mentioned method and thereafter fitting a primary reflector and a BS converter to the focus part of the reflecting mirror.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a reflecting mirror, which is a main component of a parabolic antenna of a satellite broadcast receiving system.

[Conventional technology]

Conventional VHF broadcasting is around 100MHz, so the wavelength is 3.
In contrast to I11, satellite broadcasting uses a higher frequency of the 12 GHz band, so the wavelength is about 2.5 cm (satellite broadcasting cannot be received with a conventional Yagi antenna). Therefore, satellite broadcasting can be received by using a parabolic antenna that provides high gain. This parabolic antenna has the shape of a paraboloid of revolution, and is designed to concentrate and reflect radio waves at its focal point by pointing toward the broadcasting satellite. Generally, an offset parabolic antenna is used, which uses a part of a large paraboloid of revolution. The advantage of this method is that the primary radiator can be set around the reflector, and the reflector can be designed to be smaller accordingly.

Conventionally, there are the following methods for manufacturing a reflecting mirror for a parabolic antenna for this purpose.

First, a base body of a reflecting mirror having a paraboloid of revolution is created by a method such as injection molding. At this time, the resin used is FRP. Next, a metal foil or mesh made of aluminum or the like is cut and pasted along the inner surface of the reflector. Finally, apply weather-resistant paint to the entire interior and exterior surfaces.

In this case, in the process of cutting and pasting the metal foil or metal mesh, since the reflecting mirror is not made of a paraboloid of revolution, the metal foil or metal mesh must be cut and pasted by hand, resulting in extremely poor productivity. ing. Moreover, if the paste fails and wrinkles occur, the reality is that the reflector itself is disposed of as it cannot be repaired. For the above reasons, the production cost of parabolic anti-slips is extremely high.

Other manufacturing methods include 1. A method of deep drawing pressing a metal plate such as aluminum; 2. There is a method in which metal foil, metal mesh, or metal woven fabric is set in a mold when resin is injection molded, but the former cannot produce large diameter products due to cost issues. Moreover, in the latter case, the foil etc. may be cut or wrinkled during pressing.

Previously, the present inventor disclosed a method for manufacturing a reflective mirror in which a mold is coated with conductive paint in advance and then resin is injected (Japanese Unexamined Patent Publication No. 2-32603). It was found that it took time and production efficiency was not good.

[Problems to be Solved by the Invention] The present invention has been developed by studying a method for improving workability and dramatically reducing the defective rate during the manufacturing of reflective mirrors, and by developing a manufacturing method disclosed previously (Japanese Unexamined Patent Application Publication No. 2003-100002-1). This was completed while improving the 32603).

Means for Solving Problem C] That is, the present invention provides a method for manufacturing a reflector for a parabolic antenna, in which a release layer is first formed on the entire surface of a film or cloth by printing or painting, and then a release layer is further formed on the entire surface of the film or cloth. A weather-resistant paint layer and a conductive paint layer are sequentially formed, and this transfer printed material is placed in a mold. After the resin is injected or injection molded into the mold and solidified, the molded product is taken out and the film is Alternatively, there is a method for manufacturing a reflecting mirror for a parabolic antenna, which is characterized in that a weather-resistant paint layer and a conductive paint layer are transferred to the surface of a molded product when the cloth is peeled off from the molded product.

[Function] The conductive paint referred to in the present invention refers to a paint containing metal powder or carbon powder as a filler, and can be painted with a spray gun or screen printed. In this case, the metal powder is silver powder.

Copper powder and nickel powder are suitable, and the paint may be acrylic, urethane, epoxy, phenol, etc.

Acrylic-based copper paint is the most desirable in terms of cost and performance. In this case, since it is cured at room temperature, no particularly large-scale heat curing equipment is required, and a warm air dryer is sufficient to shorten the drying and curing time. Further, even after curing, since acrylic is a thermoplastic resin, the resin constituting the antenna base is injection molded at high temperature and pressure, so that the acrylic partially hardens and becomes movable.

As a result, the acrylic resin that was interposed between the copper powder moves during injection molding, and as a result, contact between the copper powders progresses.
l The conductivity of the coating film is improved.

In order to improve the reception characteristics of a parabolic antenna, it is necessary to lower the surface resistance value of the reflective layer. Since the conductivity of the copper coating film is improved during injection molding, the reception characteristics are better compared to the method of painting the molded product with copper paint. Furthermore, in the present invention, since injection molding is performed at high temperature and high pressure, the adhesion is also good.

As the film or cloth referred to in the present invention, films of polyethylene terephthalate, polyimide, etc. are suitable, and as cloth, nylon cloth, cotton cloth, etc. are suitable. Since the paint layer is transferred onto a curved surface, it must have stretchability. By preparing a film or cloth that is continuously printed and operating the film or cloth feed/winding device and the injection molding device in conjunction, continuous production becomes possible and productivity is improved.

The release agent may be silicone-based or wax-based so that the layer can be easily peeled off during transfer. The presence of a layer of release agent facilitates transfer.

When injecting resin, it is desirable to use a two-component curing type polyurethane resin. In this case, the curing reaction is completed within 1 to 10 minutes after the resin is injected into the mold, so there is no need to inject the resin at high temperature and pressure as in normal injection molding, and the equipment is relatively simple and the mold is inexpensive. I can deal with it.

On the other hand, when injection molding resin, there are no particular restrictions as long as the resin can be injected, but since it will be used for many years, it must be able to withstand wind pressure and impact, and ABS
Resin, PPE resin or glass fiber composite AB
S resin is preferable.

[Example] A method of manufacturing a reflecting mirror for a parabolic antenna using the present invention will be described with reference to the drawings.

First, a fluororesin-based weather-resistant paint 12 (Nidoflon manufactured by Nitto Denko ■) is applied to a film thickness of 30 μm on a nylon cloth 14 that has been coated with a wax-based peeling agent 13 to a thickness of 30 μm and dried.
It was coated and dried to a thickness of m. Furthermore, copper powder 60
(manufactured by Fukuda Metal Foil & Powder Industry ■, product name FCC115A)
and 40 parts of Medium (manufactured by Teikoku Ink Manufacturing Co., Ltd.).

Mix paste 11 (trade name: Medium) with a 120 mesh screen to a film thickness of 90 g/n'T (after drying).
After printing, it was dried and cured in an oven at 80°C.

After installing this printed matter 10 with the right side facing the mold so that the copper coating film is on the inner surface of the reflecting mirror, resin (manufactured by Asahi Kasei Kogyo ■, product name STYRAC 8240A) is applied at 240°C and injection pressure 30°C.
Injection molding was performed at 0 kg/c1il. After the resin solidifies,
The molded product was taken out and the nylon cloth 14 was peeled off.

Since the release layer 13 was applied in advance, the copper coating layer 11 and the weather-resistant coating layer 12 were transferred to the inner surface of the molded product, ie, the reflecting mirror. In this case, the surface of the weather-resistant paint layer 12 is smooth, and the surface of the copper paint layer 11. The adhesion between the weather-resistant paint N12 and the substrate 30 (reflector) was good.

After applying the final coating to the reflector manufactured by the above method, the parabolic antenna is completed by attaching a primary reflector and a BS converter to the focal point of the reflector.

〔Effect of the invention〕

In the conventional method, metal foil or metal mesh was cut and pasted by hand, resulting in poor productivity and a high defect rate. In contrast, in the present invention, a film or cloth pre-coated with conductive paint and weather-resistant paint is prepared, inserted into a mold, and resin is injection molded, resulting in extremely high production efficiency. Further, in the method of the present invention, since the radio wave reflecting surface is a replica of the mold surface, both dimensional accuracy and surface roughness are improved, and as a result, reception characteristics are also improved.

As described above, the present invention greatly contributes to improving productivity and quality when manufacturing a reflecting mirror for a parabolic antenna.

[Brief explanation of drawings]

FIG. 1 is a process diagram of an embodiment of the present invention. Figures 2 and 3
FIG. 4 is a schematic diagram showing an embodiment of the present invention, respectively. 10, printed matter for transfer 11, conductive paint layer 12, weather-resistant paint layer 13, release layer 14, cloth 21, mold 22, mold 23, resin injection port 30, reflector base

Claims (1)

[Claims] (1) In the method of manufacturing a reflector for a parabolic antenna, first a release agent layer is formed by printing or painting on the entire surface of a film or cloth, and then a weather-resistant paint layer and a conductive paint layer are sequentially formed on top of it. create something that
After placing this transfer printed matter in the mold, resin is injected or injection molded into the mold, solidified, the molded product is taken out, and when the film or cloth is peeled off from the molded product, a weather-resistant paint layer and conductive paint are removed. A method for manufacturing a reflector for a parabolic antenna, characterized by transferring a layer onto the surface of a molded product.