JPS6024702A - Electromagnetic wave reflector excellent in weatherproofness - Google Patents

Abstract

PURPOSE:To increase weatherproofness by forming uneven pattern on the surface resin layer of a reflecting face of an electromagnetic wave reflector consisting of a fiber reinforced unsaturated polyester resin layer and a conductive layer inside of the former. CONSTITUTION:Fiber reinforced unsaturated polyester resin forming material made of glass fiber soaked with resin compound is put on a die having uneven pattern consisting of protruded parts 9 and recessed parts 10. A sheet of ''Toreca'' cloth #6343 carbon fiber textile is placed on it, and fiber reinforced unsaturated polyester resin forming material similar to the above is put in as a reinforcing layer, and formed at temperature of 120 deg.C and pressure of 20kg/cm<2> for 3min. Thus, an electromagnetic wave reflector 1 having uneven pattern consisting of protruded parts of about 4mm. square and recessed parts of 0.3mm. deep and 1mm. wide on the surface, having a surface layer 3 and a reinforcing layer 5 made of fiber reinforced unsaturated polyester resin, and having central conductive layer 4 made of unsaturated polyester resin containing carbon fiber textile is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic wave reflector with excellent weather resistance.

Conventionally, thermosetting resin electromagnetic wave reflectors have been manufactured by various molding methods using fiber-reinforced unsaturated polyester resin molding materials and conductive materials, and have been mainly used as reflectors for outdoor parabolic antennas. The surface of such a reflector is not made of a fiber-reinforced unsaturated polyester resin layer, and as it is exposed to sunlight and wind and rain, the surface deteriorates and peels from the conductive molding material layer or the glass fibers in the unsaturated polyester resin layer deteriorate. The surface is exposed, and contaminants in the air then adhere to it, leaving the outer surface dirty and deteriorating its appearance.

Furthermore, as this deterioration phenomenon progresses, the conductive material layer may detach,
Diffuse reflection of incident electromagnetic radiation due to deformation increases. Alternatively, in the fiber-reinforced unsaturated polyester resin layer, peeling occurs at the interface between the unsaturated polyester resin and the glass fibers, and cracking gradually occurs to the inside, resulting in a significant decrease in strength performance.

As a result of intensive research to improve the weather resistance of thermosetting resin electromagnetic wave reflectors, the inventors of the present invention have found that by forming an uneven pattern on the resin layer on the reflective surface of the electromagnetic wave reflector, the weather resistance can be improved. The present invention was achieved by discovering that an excellent electromagnetic wave reflector can be obtained.

That is, the present invention provides an electromagnetic wave reflector in which at least the surface on the reflective surface side is made of a fiber-reinforced unsaturated polyester resin layer, and the inside thereof is a conductive layer. A linear convex portion with a width of 0.1 to 5 mm and/or a regular or irregular convex portion that fits into a rectangle of 10 m in length and 10 mm in width is formed by a concave portion with a depth of 0.05 to 1.0 mm. The object of the present invention is to provide a plastic reflector with excellent weather resistance.

The fiber-reinforced unsaturated polyester resin used in the present invention is obtained from a fiber reinforcement material and an unsaturated polyester resin. Examples of the fiber reinforcing material in this case include glass fiber, carbon fiber, etc., and usually have long fibers or a length of 25 to 50 mm in order to provide strength to the electromagnetic wave reflector. In addition, unsaturated polyester resins that are generally used for molding may be used, such as unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, or lower alkyl esters thereof; phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride,
Saturated dicarboxylic acid such as adipic acid or its lower alkyl ester; ethylene glycol, propylene glycol, butanediol, diethylene glycol, diethylene glycol, bisphenol A, hydrogenated bisphenol A
Unsaturated polyesters obtained using polyhydric alcohols such as alkylene oxide adducts of 1-bisphenol A, glycerin, and trimethylolpronochloride, and unsaturated monomers such as styrene, methacrylic acid alkyl esters, and acrylic acid alkyl esters. It consists of. As this unsaturated polyester resin, polyepoxy compounds such as Evicron-850, -85DH, -830, -840 are used.
(both manufactured by Dainippon Ink Chemical Co., Ltd.), Epicoat-10
It is also possible to use vinyl esters obtained by reacting 01, -1004, and -834 (all manufactured by Shell) with (meth)acrylic acid and the unsaturated monomers mentioned above. Such molding materials usually contain 10 to 50% by weight of fiber reinforcing material, and the unsaturated polyester resin and fiber reinforcing material may be mixed at the time of use, or SMC (sheet molding compound) or BMC ( It may also be an uncured mixture of an unsaturated polyester resin such as a bulk molding compound and a fiber reinforcing material. In addition, other fillers, thermoplastic low-shrinkage imparting agents, curing agents, curing aids, mold release agents, pigments, and other known materials may be mixed into the above-mentioned molding material, regardless of their type.

The conductive substances used to obtain the conductive layer in the present invention include, for example, metals such as copper, silver, iron, aluminum, stainless steel, and nickel, and carbon powders, foils, fibers, mats, and textiles; metal plates; Known materials such as wire mesh, metal-coated mica powder, and metal-coated glass fiber can be used.

The surface layer on the reflective surface side of the electromagnetic wave reflector of the present invention is made of fiber-reinforced unsaturated polyester resin, and almost entirely has a medium-free surface layer.
．． A linear convex portion of 1 to 5 mm, preferably 0.5 to 3 mm, and/or a regular or irregular convex portion that fits into a rectangle with a length of 10 mm and a width of 10 mm, preferably a rectangle with a length of 7 mw and a width of 711 + l + 1. is partitioned into four parts with a relatively narrow width, that is, 0.1 to 5 squares, preferably 0.2 to 6 squares. In addition, such linear convex portions are so-called linear, zigzag, or patterned, and have a length of 10 asg.
The regular or amorphous convex portion that fits into the square with a width of 10 mm may be circular, angular, dot-like, or any other shape.

The electromagnetic wave reflector of the present invention can be produced by forming a surface layer with an uneven pattern as described above on a conductive layer obtained by molding a metal plate, and further forming a reinforcing layer on the back surface as necessary. conductive unsaturated polyester resin obtained by combining a conductive substance and an unsaturated polyester resin as a molding material for forming a conductive layer;
For example, when an unsaturated polyester resin containing conductive powder and/or a conductive mat is used, and if necessary, a fiber-reinforced unsaturated polyester resin is used as a molding material for the reinforcing layer, a general FRP molding method, For example, handley attach method, spray up method, resin injection method, Matsushido e-mold die method, SMC and BMC
Compression molding method) is preferable because the electromagnetic wave reflector of the present invention can be obtained easily and efficiently.

Among these, compression molding using a mold with an uneven pattern is preferable because it allows integral molding. Materials for the mold used during molding include wood, resin, aluminum, iron, plaster, etc. However, considering the ability to form a noticeable uneven pattern on the surface of the electromagnetic wave reflector, the material for the mold is metal. is desirable.

The electromagnetic wave reflector of the present invention and its uneven pattern will be explained below with reference to the drawings.

Figure 1 is a perspective view of a parabolic antenna using an example of the electromagnetic wave reflector with excellent weather resistance of the present invention, and Figures 2 to 5 are plan views showing specific examples of the uneven pattern on the reflective surface of the electromagnetic wave reflector. It is.

Next, the present invention will be explained using examples. All parts and percentages in the examples are based on weight.

Example 1 A fiber-reinforced unsaturated polyester resin molding material made of the following glass fibers (glass fiber content 30%) impregnated with the following resin compound was placed on a mold having an uneven pattern as shown in Figure 2. Insert the trading card cross on top of it≠6
346 (carbon fiber fabric manufactured by Toshisha Co., Ltd.) was placed, and then the same fiber-reinforced unsaturated polyester resin molding material as above was added as a reinforcing layer, and molded under the heating and pressure conditions described below. Approximately 4 mm square convex part and 0.3 m deep
The surface has an uneven pattern consisting of recesses with a width of 1 mm, the surface layer and the reinforcing layer are made of fiber-reinforced unsaturated polyester resin, and the conductive layer in the center is an unsaturated polyester resin containing carbon fiber fabric. A three-layer electromagnetic wave reflector of the present invention was obtained.

<Resin compound> Unsaturated polyester resin (Polylite PM-141, Dainippon 100 parts manufactured by Ink Kagaku Co., Ltd.) Calcium carbonate (MS-200, Japan 70 parts manufactured by Shufunka Co., Ltd.) Benzoyl peroxide paste 2 parts (hardening agent, Japan) (Manufactured by Yushisha Co., Ltd.) Gray pigment (PC-3575, thick 2 parts, manufactured by Nippon Ink Chemical Co., Ltd.) <Glass fiber> Concave and convex pattern side Surf Ace mat (manufactured by Asahi Fiber Glass Co., Ltd.) 50 g/mF 1 sheet Inside of the concave and convex pattern surface Continuous mat (manufactured by Asahi Fiberglass Co., Ltd.) 450I/rrL2 3 sheets <Heating and pressure conditions> Temperature 120°C, pressure 20)g/i, molding time 3 minutes Example-2 Example except that the molding conditions were changed to the following Comparative Example-1 The depth of the concave part of the electromagnetic wave reflector after molding was set to CJ, 05 rgm in the same manner as in 1.
An electromagnetic wave reflector having a concavo-convex pattern was obtained in the same manner as in Example-1 except for the following.

Comparative Example-2 An electromagnetic wave reflector without an uneven pattern was obtained in the same manner as in Example-1 except that a smooth mold without an uneven pattern was used.

Test Examples The electromagnetic wave reflectors of Examples-1 and -2 and Comparative Examples-1 and -2 were subjected to a sunshine weather resistance test and an outdoor exposure weather resistance test. The results are shown in Tables-1 and -2.

[Brief explanation of drawings]

Figure 1 is a partially cutaway perspective view of a parabolic antenna using the electromagnetic wave reflector with excellent weather resistance of the present invention, and Figures 2 to 5 are plan views showing specific examples of the uneven pattern on the reflecting surface of the electromagnetic wave reflector. be. 1: Electromagnetic wave reflector, 2: Reflective surface, 3: Surface layer with uneven pattern, 4: Conductive layer, 5: Reinforcement layer, 6: Reflective horn, 7: Arm, 8: Support, 9: Convex part , 10: recess. Agent Patent Attorney 11 Harutoshi Takahashi Figure-4 Figure-5

Claims (1)

[Claims] In an electromagnetic wave reflector in which at least the surface on the reflective surface side is made of a fiber-reinforced unsaturated polyester resin layer and the inside thereof is a conductive layer, the entire surface of the reflective surface of the electromagnetic wave reflector has a width of 0.1 ~5 rtrm'AfJ-shaped convex part and/or a regular or amorphous convex part that fits in a rectangle with a length of 10 mm and a width of 10 mm is formed by four parts with a depth of 0.05 to 1.0. An electromagnetic wave reflector with excellent weather resistance.