JPH03224307A - Reflector and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce the man-hour required for packing of a surface protective layer by forming a fiber mixed thermosetting resin as the backup material and a conductive reflection material as the reflection material into one body in a cavity having a reflector form and charging a thermosetting resin between a core mold face and the resin formed body and heating and pressurizing them again to form the surface protective layer. CONSTITUTION:A core mold 10 is stamped with the form of the reflection face of a reflector, and a cavity mold 11 is stamped with the form of the backup face of the reflector, and a cavity S is formed between them. A brass wire net is used as conductive materials 2 for radio wave reflection, and a sheet molding compound containing 26wt.% glass is laminated as a backup material 1. It is thrown into molds 10 and 11 for 45 type offset reflector, and about 2mm space (b) is opened after molding by heat and pressure. After a one liquid urethane resin is charged as a surface protective material 3 into a tub 17 by an injector 14 in such a state, they are molded again by heating and pressuring. By this pressure, the resin in the tub 17 is quickly moved to the surface of the reflection material 2.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a reflector for microwaves, etc., which can be used for receiving satellite broadcasting, transmitting and receiving communications satellites, and furthermore, for wireless relay stations, etc., and a method for manufacturing the same. In particular, the present invention relates to a reflector that takes into consideration the formation of a surface protective layer on the synthetic resin reflector, and a method for manufacturing the same.

[Conventional technology]

Currently, many parabolic antenna reflectors are mainly made of synthetic resin;
Weather-resistant resin is formed on the surface, and it is also common to have an attractive color applied to the surface.

There are the following three methods for forming this surface protective layer.

The first method is to integrate conductive nonwoven fabric, wire mesh, or aluminum foil with adhesive treatment on one side with SMC (sheet molding compound) by heat compression molding, then take out the molded product, sand it, and then There is a method of applying post-coating by spraying etc. According to this method, equipment for a painting line is required, and furthermore, primer coating or sanding treatment is required to ensure the adhesion of the top coat, and therefore the overall cost increases.

The second method is to heat and compression mold the SMC as it is with a wire mesh sandwiched between them to form a protective layer, but this method is difficult to flatten the surface due to sink marks during resin molding, and visual inspection is also required. In some cases, this was a drawback that was difficult to detect.

Furthermore, as a third method, a method has been proposed in which a weather-resistant resin film serving as a surface protective layer is laminated or aluminum foil coated with resin is used, and this is overlaid and integrated with the above-mentioned SMC. It is necessary to preform this film into the shape of a reflector, which significantly increases the number of work steps.

Furthermore, in many cases, the front and back sides of the reflector are made to have different colors, but the first method requires a long time for masking, and the second method is technically difficult. Furthermore, in the third method, a boundary was created between the edge of the resin film (laminated with aluminum foil) and the SMC serving as a backup material at the flange portion of the reflector, which was not desirable in terms of design.

In addition to this, a fourth method is to use conductive nonwoven fabric or wire mesh as SMC.
There is also a method in which the mold is placed on top of the molded body and molded under heat and pressure, then the mold on the front side is opened, a thermosetting resin that will become the surface protective layer is poured onto the surface of the molded object, and the mold is closed again and the protective layer is formed by heat and pressure. It has been proposed (Japanese Unexamined Patent Publication No. 61-430
No. 4).

However, with this method, the mold on the front side is completely opened once, so there is a risk that foreign matter such as paris generated around the molded product will fall onto the surface and cause surface defects on the most important reflector. there were.

Furthermore, the resin that is poured into the hole also has the disadvantage of causing uneven coloring if the heat is not suitable.

[Problem to be solved by the invention]

The present invention provides the above-mentioned fourth method which is excellent in terms of design and cost.
The present invention is a further improvement of the above method, and aims to provide a reflector that reduces the number of steps required for filling the surface protective layer and prevents color unevenness, and a method for producing the reflector.

[Means to solve the problem]

A method for manufacturing a reflector according to the present application: A cavity in the shape of a beam reflector is provided, and the core mold is carved with the reflective surface of the reflector, and the cavity mold is formed with the backup surface of the reflector. After integrally molding the short fiber-containing thermosetting resin and the conductive reflective material that will serve as the reflector's reflective material in a cavity under heat and pressure, the pressure of the mold is released or reduced, and the core mold is formed. A feature is that a thermosetting resin to serve as a surface protective layer is injected between the surface and the resin molded body, and then heated and pressed again to form a weather-resistant surface protective layer on the reflective side surface.

The reflector according to the present application includes a paraboloid that reflects radio waves, a flange portion folded back to the outer peripheral edge, and a flat portion formed therebetween as necessary.
The folding angle of the 7 rungs is 3° to the punching direction.
30°, and is characterized in that a surface protective layer is also formed on the flange portion.

Here, the conductive reflective material referred to in this application includes woven or non-woven fabrics of conductive fibers such as aluminum coated glass, carbon fiber, nickel-plated polyester, nickel-plated glass, or metal fibers such as brass wire, aluminum wire, galvanized iron wire, etc. The wire mesh or metal wire/glass mixed fabric is flexible, and can be laminated with a thermosetting resin sheet and integrally molded by simply punching it out.

In this case, as an adhesive layer, a laminate group is prepared by laminating aluminum foil with a hot-melt film made of modified polyolefin, nylon, urethane, ethylene-vinyl acetate copolymer, etc., or double-sided polyvinyl fluoride film, etc., which is then preformed. It is also possible to use it as

Thermosetting resin molding materials that serve as back-up materials are generally reinforced with glass fibers, and SMC (
Examples include sheet molding compound (sheet molding compound), BMC (bulk molding compound), TMC (thick molding compound), and glass cloth prepreg.

In addition, if necessary, interposing a woven fabric or non-woven fabric made of glass fiber, polyester fiber, vinylon fiber, etc. between the conductive reflective material and the thermosetting resin material is to prevent the reflective material from being disturbed or cut. It is effective for

On the other hand, as the surface protective layer, a cured resin such as urethane type, polyester type, vinyl ester type, epoxy type, epoxy acrylic type, or a resin modified or mixed with these resins can be used. There are two-component systems: one-component systems in which the curing agent is mixed in advance, and two-component systems in which the curing agent is separated, but in the case of thermal curing, it is more effective to use a one-component system because it does not require a mixing device or the like.

In the present invention, when injecting the resin that will become the surface protective layer, the pressurized state is released, but this can be done by actively forming a very small gap between the upper and lower molds, or by applying pressure. There are two methods: lowering the pressure and press-fitting the resin under high pressure. The former is to reduce the pressure to 0 or less, and the latter is to reduce the pressure not to 0 but to the extent that the resin can be press-fitted.

In the former case, it is preferable to raise the upper mold once, and for this reason, it is preferable to provide a plurality of cylinders that push the upper mold upward in the opposite direction to the downward pressure of the press. In this case, the resin may be injected using a low pressure such as a nitrogen cylinder of 150 kg/Crl or less, and the resin is supplied into the cylinder by a static mixer.

Generally, the injector is attached to the mold via a heat insulating plate or a cooling zone, and the injector is press-fitted into the mold by opening and closing a shaft off pin.

On the other hand, in the latter case, the pressure is lowered or released, but the resin is press-fitted in the closed state, so the pressure is lowered or released.
A high pressure of 100 to 400 kg/cat is required for the press mold clamping pressure of ~100 kg/ctl, and it is necessary to generate high pressure with an accumulator and introduce it into the cylinder of the injector.

In either case, it is possible to provide the injection port for the resin that forms the surface protective layer on the molding surface of the mold, but considering the appearance of the molded product, the injection port for the resin forming the surface protective layer may be provided at the edge of the cylinder. Place one or two tabs on the holder and inject the liquid there.
From here, a method should be adopted in which the resin is spread around the surface of the molded product. In this case, the tab portion will be cut out after the cylinder is removed from the mold.

The amount of such resin injected is determined by the size of the beam cylinder, but a good film can be obtained with a film thickness of 30 to 300 μm, preferably 50 to 150 μm.

Generally, a reflector made of synthetic resin has a flange formed around it, and this flange forms the boundary between the reflective material, the end, and the backup material resin. It is also necessary to form a surface protective layer. For this reason, the flange portion preferably opens outward by 3° to 30° with respect to the drawing direction, and generally preferably opens outward by 10° or more. This is 3
If it is less than 30 degrees, the protective layer becomes thin and the conductive reflective material lacks hiding power, and if it exceeds 30 degrees, the paraboloid tends to warp, resulting in poor paraboloid accuracy and is also undesirable in terms of design. It depends.

〔Example〕

FIG. 1 shows a partial cross-sectional view of a cylinder manufactured in accordance with the present invention. A conductive reflective material 2 is formed on the surface of a back-up material 1 serving as a base material of the reflector. Furthermore, a surface protection layer 3 is formed on the surface of this reflective material 2. The circumference of these backup material 1, conductive reflective material 2, and surface protection layer 3 is continuous via a flat part F to a flange part 4 bent at an acute angle from this flat part F.

As can be seen from the image, a boundary a between the backup material 1 and the conductive reflective material 2 is exposed at the flange portion 4 of the reflector, which is shown to be covered with the surface protection layer 3. The flange portion 4 is shaped to open outward at an inclination angle θ with respect to a perpendicular line at the outer end of the flat portion F.

Experimental Example 1 FIG. 2 shows a core mold 10, a cavity mold 11, and various devices associated therewith, which are used in the reflector manufacturing method in Experimental Example 1. Code 1 in the diagram
2 is a resin supply device, 13 is a nitrogen cylinder for pressurization, 14 is an injector, and 15 is a shut-off cylinder.

Further, the core mold 10 is engraved with the shape of the reflective surface of the beam cylinder, while the cavity mold 11 is similarly engraved with the shape of the backup surface of the beam cylinder, and a cavity S is formed between them. be done. Reference numeral 16 in the figure is a boss portion for attaching the reflector into which an M6 nut is inserted. Furthermore, a tab 17 serving as a resin reservoir is provided at the end of the flange of the cavity mold 11.

Now, a brass wire mesh (wire diameter 150 μm x 24 meshes) is used as the conductive material 2 for electromagnetic wave reflection, and the backup material 1
1 kg of a sheet molding compound having a glass content of 26 wt% was weighed and laminated.

This is molded into mold 10 for a 45-inch offset reflector.
11, mold clamping pressure 100 tons, mold temperature 14
Heat and pressure molding was performed at 0° C. for about 90 seconds. After that, hydraulic cylinders placed at the four corners of the press were operated to open a gap of about two inches.

In this state, measure approximately 30 cc of one-component urethane resin (a urethane resin made of acrylic polyol, non-yellowing isocyanate, and toner, with peroxide and catalyst added as a hardening agent) using the injector 14, and shut off. Nitrogen cylinder 1 is released by opening cylinder 15.
The gas pressure from No. 3 was injected into the tub 17 at a pressure of about 50 kg/cIIt using reduced pressure. After injection, the cylinders at the four corners were lowered, a press ram pressure of 100 tons was applied again, and the mold was heated and pressed at a mold temperature of 140° C. for about 90 seconds.

Due to this pressurization, the resin inside the tab 17 suddenly changes to the reflective material 2.
move to the surface of Further, since the flange portion 4 is inclined by the angle θ (FIG. 1), sufficient communication of the resin from the tab 17 is ensured as long as the molds 10, 11 are slightly separated.

The resulting cylinder has a film thickness of approximately 120μ on the reflective surface.
A good molded product with a gray color N8.0 of approximately 30 μm at the m1 flange portion 4 and having an excellent appearance and no color unevenness was obtained.

In addition, in the figure, the gap is exaggerated, and the core mold 10 and the cavity mold 11 are
There shall be no gaps beyond this.

Further, since the flange portion has an angle of θ-about 5° C., as can be seen from the image side, a surface protective layer is also formed on the surface of this flange portion.

Experimental Example 2 FIG. 3 shows the core mold 10, cavity mold 11, and various devices associated therewith in the reflector manufacturing method in Experimental Example 2.

In the figure, reference numeral 18 indicates a high-pressure pump, 19 indicates a shut-off bin, and the others are the same as in the previous example.

As in Experimental Example 1, the conductive reflective material 2 made of brass wire mesh and the SMC backup material 1 were laminated and placed in a mold 10.11 for a 45-type reflector. A tab 17 of approximately 25 mm square is provided in advance on the mold 11, and a shaft-off nozzle is inserted into this tab. As before, heat and pressure molding was carried out at a mold clamping pressure of 100 tons and a mold temperature of 140° C. for about 80 seconds, and then the mold clamping pressure was released without opening the mold.

In this state, 40 cc of resin was measured using the injector 14 and injected at a high pressure of 300 kg/ci using hydraulic pressure. That is, the mold 10 is lifted by the resin pressure. After the injection, a mold clamping pressure of 100 tons was applied again, and heating and pressure molding was performed for about 90 seconds.

The resulting cylinder has a film thickness of approximately 120 μm on the reflective surface.
The flange portion was covered with a good light gray protective layer of about 40 μm.

Experimental Example 3 Brass wire mesh and SMC were laminated in the same manner as Experimental Example 1, and this was placed in a mold for a 75-type offset reflector with a flange angle θ = 30°, and the clamping pressure was 400 tons and the mold temperature was 140°C. The molded product was heated and pressed for about 120 seconds.

Thereafter, hydraulic cylinders placed at the four corners of the press were operated to create a gap of about 2 mm between the molds 10 and 11, and about 140 cc of one-component urethane resin was injected. After injection, the mold was heated and pressed again at a mold clamping pressure of 300 tons and a mold temperature of 140° C. for about 90 seconds. The resulting reflector has a reflective surface area of about 140
The flange portion was covered with a good protective layer having a thickness of about 80 μm.

Experimental Example 4 Brass wire mesh and SMC were laminated in the same manner as Experimental Example 2, and this was placed in a mold for a 35-type offset lift crater with a flange angle θ of 12°, the clamping pressure was 70 tons, and the mold temperature was 150°C. After heating and pressurizing the mold for about 70 seconds, the mold clamping pressure was released without opening the mold.

In this state, the resin was adjusted to white using an injector. Approximately 2.
5 cc was injected at high pressure of about 300 kg/crl.

After injection, the molding was again carried out under heat and pressure. The obtained reflector was covered with a protective layer having a good white color and excellent hiding power, with a reflective surface part of about 120 μm and a flange part of about 50 μm.

〔Effect of the invention〕

The present invention employs the above-mentioned manufacturing method, so that it is possible to reliably form the surface protective layer not only on the paraboloid but also on the flange without contaminating the most important receiving surface of the reflector. have an effect.

In addition, it is possible to form a surface protective layer with excellent adhesion and durability in one coat without any base treatment or primer, making it an inexpensive reflector with an excellent design.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of a reflector manufactured according to the present invention, and FIG. 2 is a reflector applied to the first embodiment.
Conceptual Diagram of Manufacturing Apparatus FIG. 3 is a conceptual diagram of the manufacturing apparatus in the second embodiment. DESCRIPTION OF SYMBOLS 1... Backup material, 2... Conductive reflective material, 3... Surface protective layer, 4... Flange part, 10... Core mold, 11... Cavity mold, 12... Resin Supply device, 17...Tab, C...Cavity.

Claims (2)

[Claims] (1) A cavity is provided between a core mold that forms the reflective side surface of the reflector and a corresponding cavity mold that forms the backup side back surface of the reflector, and a conductive material that becomes the reflective material of the reflector is provided within this cavity. After the fiber-reinforced thermosetting resin that serves as the reflective material and backup material is integrally molded under heat and pressure, the pressure on the mold is released or reduced to form a surface protective layer between the core mold surface and the resin molded body. A method for manufacturing a reflector, characterized by forming a weather-resistant surface protective layer on the reflective side surface by injecting a thermosetting resin and heating and pressurizing it again. (2) In a reflector that has a paraboloid that reflects radio waves, a flange portion folded back to the outer periphery, and a flat portion formed therebetween as necessary, the folding angle of the flange portion is 3° to 30° with respect to the drawing direction. 2. The reflector manufactured by the method according to claim 1, wherein the surface protective layer is also formed on the flange portion.