JPH0469441B2 - - Google Patents

Description

[Detailed description of the invention]

[]Purpose of the Invention The present invention provides circularly polarized waves made of a laminate consisting of a thermoplastic resin layer with excellent weather resistance, a metal foil that reflects radio waves, and an olefinic polymer layer containing an inorganic filler that functions as a structure. The present invention relates to a method of manufacturing a reflector for an antenna. More specifically, a metal foil laminated with a thermoplastic resin layer with excellent weather resistance on one side and an olefinic polymer layer on the other side is used, and the thermoplastic resin layer of the laminated metal foil is injected. The olefin polymer layer is attached to the movable mold surface of the molding mold so that it is on the stationary mold side, and after the mold is closed, the olefin polymer containing an inorganic filler is injection molded. This relates to a method for manufacturing a reflector for a circularly polarized antenna, which is characterized by a circularly polarized antenna that has significantly improved adhesion between the metal foil and the inorganic filler-containing olefinic polymer layer that functions as a structure. The purpose of this invention is to provide a reflector for []Background of the Invention Satellite broadcasting using geostationary satellites is planned to be put into practical use in Europe, America, Japan, and other countries around the world in the near future. However, since a geostationary satellite has only one orbit, there is a risk of interference between multiple broadcast radio waves. In order to avoid such mutual interference of broadcast waves, it is necessary to utilize cross-polarization identification of satellite broadcast receiving antennas. In this way, when receiving terrestrial broadcast waves, the radio waves are linearly polarized horizontally or vertically, and the polarization plane of the receiving antenna is matched to the polarization plane of the broadcast waves, using cross-polarization discrimination. However, when receiving radio waves from a broadcasting satellite, there is a shift in the plane of polarization due to disturbances caused by the ionosphere in the radio wave propagation path and the angle of incidence of the radio waves at the receiving point, so the above-mentioned It is difficult to match the planes of polarization. Frequency allocation to multiple broadcasting satellites is likely to be done taking into account the degree of polarization plane discrimination from the point of view of effective use of satellite broadcasting frequency bands.
For satellite broadcast radio waves with such frequency allocation, the quality of the polarization plane adjustment of the receiving antenna directly determines the level of interference between broadcast channels, so if the broadcast satellite radio waves are linearly polarized, there will be large cross-polarization. One cannot expect to obtain any degree of discrimination. However, when broadcasting satellite radio waves are circularly polarized waves, it is easy for ordinary listeners to identify them by the direction in which the circularly polarized waves are applied, regardless of the shift in the plane of polarization as described above. The receiving antenna not only adjusts its pointing direction to point to the desired broadcasting satellite, but also does not require adjustment of the plane of polarization, making it much easier to adjust the receiving antenna than when linearly polarized waves are used. Therefore, it is possible to obtain the degree of polarization discrimination as designed for the receiving antenna. For these reasons, plans are being made to use circularly polarized waves for broadcast satellite radio waves in future satellite broadcasting systems. In contrast, conventional circularly polarized antennas include those that use a conical horn, those that combine two dipoles at right angles, and parabolic antennas that use these antennas as primary radiators. Because the structure is complex, large, and expensive to manufacture, it is not suitable for general audience receiving antennas for receiving satellite broadcast radio waves using microwaves in the 12 gigahertz (GHz) band. do not have. On the other hand, the structure is extremely simple, and as a small and lightweight microwave antenna, a rectangular waveguide is extended in the axial direction from the center of a parabolic reflector, and its tip is curved so that the opening end surface becomes a parabolic shape. so that it faces the parabolic reflector at the focal point,
There is a so-called Hihat-type parabolic antenna that uses this as a primary radiator. This antenna is widely used in microwave antennas for mobile relays, etc., but all conventional Hihatt-type parabolic antennas now transmit and receive linearly polarized waves using short waveguides as described above. Therefore, it cannot be used for circularly polarized waves. Generally, metal plates or metal nets have been used as parabolic antennas. However, since metals corrode, it is necessary to use anti-corrosion alloys or apply anti-corrosion coatings. If anti-corrosion alloys are used, they are expensive. On the other hand, regarding anti-corrosion coating,
In order to achieve complete corrosion protection, it is necessary to repeat the coating several times, which is not only expensive, but also causes the problem that the coated product deteriorates over many years of use. Furthermore, attempts have been made to manufacture radio wave reflecting plates in which glass fibers with metallized surfaces are laminated to thermosetting resins such as unsaturated polyester resins as radio wave reflecting layers, but the manufacturing method is complicated and It has been extremely difficult to maintain the radio wave reflecting layer at a constant thickness and without unevenness. []Structure of the Invention Based on the above, the present inventors aimed to obtain a reflector for a circularly polarized antenna that has a simple manufacturing process, has radio wave reflecting ability, and can maintain its performance for a long period of time. As a result of various searches, we found that using a metal foil laminated with a thermoplastic resin layer with excellent weather resistance on one side and an olefinic polymer layer on the other side, the thermoplastic resin layer of the laminated metal foil was used. is attached to the movable mold surface of an injection mold so that the olefin polymer layer is on the fixed mold side, and after closing the mold, the inorganic filler-containing olefin polymer is injection molded. We have discovered that a method for manufacturing a reflector for circularly polarized antennas characterized by We have arrived at the present invention. []Effects of the Invention The circularly polarized antenna reflector manufactured by the present invention exhibits the following effects (features) including its manufacturing process. (1) Due to its excellent corrosion resistance, there is no change in radio wave reflection characteristics over a long period of time. (2) Since the coefficient of linear expansion of the metal layer and the inorganic filler-containing olefinic polymer layer is extremely small, no separation occurs between the layers even if subjected to heat cycles (repetitive cold and hot temperatures) for a long period of time. (3) The reflector for a circularly polarized antenna is lightweight and the manufacturing process is simple. (4) The metal layer can be formed uniformly, and there is no uneven reflection of radio waves. (5) Olefinic polymers containing inorganic fillers can be easily formed into various complex shapes, and therefore have good appearance and functionality. (6) Since the olefinic polymer layer is interposed between the inorganic filler-containing olefinic polymer layer and the metal foil, which functions as a structure, the interaction between the inorganic filler-containing olefinic polymer layer and the metal foil is Adhesion has been greatly improved, and even if an attempt is made to separate the inorganic filler-containing olefin polymer layer from the metal foil, by selecting a primer for the metal foil and the olefin polymer layer, the metal foil will remain intact. It can exhibit adhesive strength to the extent that it can be cut. (7) An inorganic filler-containing olefin that functions as a structure because the olefin polymer layer on which the metal foil is laminated and the inorganic filler-containing olefin polymer layer are partially mixed during injection molding. It does not adversely affect the mechanical strength such as rigidity inherent in the polymer layer. (8) The laminated metal foil is easy to handle; for example, it can be held in a roll. (9) When setting the laminated metal foil in the mold during injection molding, the laminated metal foil can be used in a rolled state, so it can be continuously supplied, increasing productivity. will be significantly improved. []Specific description of the invention (A) Thermoplastic resin The thermoplastic resin used to manufacture the thermoplastic resin layer of the present invention is widely produced industrially and used in many fields. Their manufacturing methods and various physical properties are well known. Their molecular weight varies depending on the type, but generally ranges from 10,000 to 1,000,000. Typical thermoplastic resins include homopolymers of monomers with double bonds such as ethylene, propylene, vinylidene fluoride, vinyl chloride, and styrene, and copolymers containing these as the main component (50% by weight or more). Polymer, copolymer of styrene and acrylonitrile (AS
Resin) Resin whose main component is methyl phthalate (MMA resin) Butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber (NBR),
Rubbers such as styrene-butadiene copolymer rubber (SBR), acrylic rubber, ethylene-propylene copolymer rubber (EPR), ethylene-propylene-diene terpolymer rubber (EPOM), and chlorinated polyethylene, and styrene alone or in combination with styrene. Examples include graft copolymer resins obtained by graft copolymerizing with vinyl compounds (for example, acrylonitrile, methyl methacrylate), polyamide resins, polyester resins, polyphenylene oxide resins, and polycarbonate resins. Furthermore, even if these thermoplastic resins are modified by grafting an organic compound having at least one double bond (for example, an unsaturated carboxylic acid or its anhydride), they have excellent processability. You can use whatever you like.
Furthermore, in addition to the above-mentioned graft copolymer resin, compositions obtained by blending the above-mentioned rubber with these thermoplastic resins (the blending ratio of rubber is generally at most 40% by weight) can also be used. . Among these thermoplastic resins, fluorine-containing resins such as polyvinylidene fluoride are preferred because of their excellent weather resistance. Furthermore, resins mainly composed of vinyl chloride, ethylene and/or
Alternatively, even if the resin has propylene as its main component, its weather resistance can be improved by adding an ultraviolet absorber, so blends of these can also be preferably used. Furthermore, polyamide resins, polyester resins and polycarbonate resins can also be used. Among these thermoplastic resins, olefin resins (ethylene homopolymer, propylene homopolymer,
A modification obtained by graft polymerizing an organic compound having at least one double bond (especially preferably an unsaturated carboxylic acid and its anhydride) to a copolymer mainly composed of ethylene and/or propylene. It is advantageous to use part or all of the resin because it has excellent adhesion to the metal layer described later. (B) Metal layer Furthermore, typical examples of metals that are raw materials for the metal layer in the present invention include simple metals such as aluminum, iron, nickel, copper, and zinc, and alloys containing these metals as main components (for example, stainless steel). steel, brass). These metals do not need to be surface-treated, and may be previously subjected to surface treatment such as chemical treatment or plating treatment. Furthermore, those that have been painted or printed can also be preferably used. (C) Olefin polymer In addition, the olefin polymer used for producing the olefin polymer layer and the inorganic filler-containing olefin polymer layer on which the metal foil is laminated in the present invention is an ethylene homopolymer. homopolymers of propylene, copolymers of ethylene and propylene, copolymers of ethylene and/or propylene with other α-olefins having at most 12 carbon atoms (the proportion of copolymerization of α-olefins is high) 20% by weight). Melt index of these olefin polymers (according to JIS K-6760, measured at a temperature of 190°C and a load of 2.16 kg,
(hereinafter referred to as "MI") or melt flow index (according to JIS K-6758)
Measured under the conditions of 230°C and a load of 2.16 kg, hereinafter referred to as "MFI") is preferably 0.01 to 100 g/10 minutes, particularly preferably 0.02 to 80 g/10 minutes. If an olefinic polymer having an MI or MFI of less than 0.01 g/10 min is used, the resulting mixture will not have good moldability. On the other hand, 100g/
When using an olefin polymer that lasts for more than 10 minutes,
The mechanical properties of the resulting molded product are poor. moreover,
Low density (0.900g/cm ³ ) or high density (0.980
g/cm ³ ) of an ethylene homopolymer or a copolymer of ethylene with a small amount of the above α-olefin, or a propylene homopolymer or a random or block copolymer of propylene with ethylene and/or other α-olefins. desirable. These olefinic polymers are produced by using a catalyst system (so-called Ziegler catalyst) obtained from a transition metal compound and an organoaluminum compound, and a chromium-containing compound (e.g., chromium oxide) supported on a carrier (e.g., silica). It can also be obtained by homopolymerizing or copolymerizing olefins using a catalyst system (so-called Phillips catalyst) or a radical initiator (eg, an organic peroxide). Furthermore, in the present invention, modified materials obtained by graft polymerizing these olefinic polymers with a compound having at least one double bond (for example, an unsaturated carboxylic acid, a monobasic carboxylic acid, a vinyl silane compound) Also included are polyolefins. The production methods for these olefin resins and modified polyolefins are well known. These olefin polymers and modified polyolefins may be used alone or in combination of two or more. Furthermore, two or more of these olefin polymers and modified polyolefins may be used as a resin blend in any proportion. The production methods for these olefin polymers and modified polyolefins are well known. (D) Inorganic filler The inorganic filler used to produce the inorganic filler-containing olefinic polymer layer is generally one widely used in the fields of synthetic resins and rubber. These inorganic fillers are preferably inorganic compounds that do not react with oxygen and water and do not decompose during kneading and molding. The inorganic fillers include metals such as aluminum, copper, iron, lead and nickel, oxides of these metals and metals such as magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, antimony and titanium, and their water. It is broadly classified into compounds such as hydrates (hydroxides), sulfates, carbonates, silicates, their double salts, and mixtures thereof. Typical examples of the inorganic fillers include the above-mentioned metals, aluminum oxide (alumina), its hydrates, calcium hydroxide, magnesium oxide (magnesia), magnesium hydroxide, zinc oxide (zinc white), red lead, and lead. Lead oxides such as mortar, magnesium carbonate, calcium carbonate,
Basic magnesium carbonate, white carbon,
Asbestos, mica, talc, glass fiber, glass powder, glass beads, clay, diatomaceous earth, silica, wollastonite, iron oxide, antimony oxide, titanium oxide (titania), lithopone, pumice powder, aluminum sulfate (gypsum, etc.) , zirconium silicate, zirconium oxide, barium carbonate,
Examples include dolomite, molybdenum disulfide and iron sand. Among these inorganic fillers, those in powder form preferably have a diameter of 1 mm or less (preferably 0.5 mm or less). In addition, fibrous materials have a diameter of 1 to 500 microns (preferably 1 to 300 microns) and a length of 0.1 to 6 mm (preferably
0.1 to 5 mm) is desirable. Furthermore, the diameter of the flat plate is 2 mm or less (preferably 1 mm or less). (E) Structure of each layer (1) Thermoplastic resin layer The thermoplastic resin of the present invention prevents corrosion of the metal layer described later. It works to prevent the occurrence.
From this, the thickness is 5 microns or 5 mm.
and preferably 10 microns to 5 mm,
Particularly suitable is 10 microns to 1 mm. If the thickness of this thermoplastic resin layer is less than 5 microns, not only will the metal layer corrode, but also the metal layer will wear out and become exposed due to contact and friction with other articles during use. occurs and there is a problem. On the other hand, if it exceeds 5 mm, it is not preferable because it not only lowers the reflectance of radio waves but also increases the cost and weight of the laminate. (2) Metal layer (metal foil) Furthermore, the metal layer of the present invention functions to reflect radio waves. The thickness of this metal layer is 5
The diameter is from micron to 1 mm, preferably from 5 to 500 micron, particularly preferably from 10 to 500 micron. If the thickness of the metal layer is less than 5 microns, the metal layer is likely to wrinkle or fold during the production of a laminate, resulting in problems in terms of appearance and performance. On the other hand, 1mm
If it exceeds this, not only will the weight increase, but also the cost will increase, and furthermore, it will cause problems when bending or bending the laminate. (3) Olefin polymer layer The olefin polymer layer constituting the laminated metal foil in the present invention is an adhesive between the metal foil serving as a radio wave reflecting layer and the inorganic filler-containing olefin polymer layer functioning as a structure. This function not only improves the properties of the laminated metal foil but also facilitates storage and handling of the laminated metal foil. The thickness of this olefinic polymer layer is usually 5 microns to 500 microns,
5 to 300 microns is desirable, especially 5 to 300 microns.
200 microns is preferred. If the thickness of the olefin polymer layer is less than 5 microns, the olefin polymer will tend to wrinkle when manufacturing the laminated metal foil, which will affect the surface of the metal foil, resulting in poor appearance and performance. There is a problem with this. On the other hand, if it exceeds 500 microns, a problem arises because the mechanical properties such as strength and rigidity of the inorganic filler-containing olefinic polymer layer decrease. (4) Inorganic filler-containing olefin polymer layer The composition ratio of the inorganic filler in the inorganic filler-containing olefin polymer layer of the present invention is 10 to 10.
80% by weight (that is, the composition ratio of the olefin polymer is 90 to 20% by weight), preferably 10 to 70% by weight, and particularly preferably 10 to 60% by weight. The composition ratio of the inorganic filler in the inorganic filler-containing olefin polymer layer is 10% by weight.
If the temperature is less than 100%, the linear expansion coefficient of the inorganic filler-containing olefin polymer layer is too different from that of the metal layer, and peeling occurs between the metal layer and the inorganic filler-containing olefin polymer layer due to heat cycles. In addition, there is a problem that the rigidity of the obtained laminate is insufficient. On the other hand, if it exceeds 80% by weight, it is difficult to produce a uniform composition, and even if a uniform composition is obtained, it will be difficult to produce a laminate by sheet production or injection molding as described below. In this case, it is not possible to obtain a good product (laminate). The thickness of this inorganic filler-containing olefinic polymer layer is 500 microns to 15 mm;
-10 mm is desirable, and 1-7 mm is especially suitable. If the thickness of the inorganic filler-containing olefinic polymer layer is less than 500 microns, it is undesirable because it lacks rigidity and may be deformed or damaged by external force. On the other hand, if it exceeds 15 mm, it will take time to cool down during molding, and not only will sink marks be more likely to occur on the surface, but the weight will increase, causing problems in use. In producing the thermoplastic resin layer, the olefinic polymer layer, and the inorganic filler-containing olefinic polymer layer, stabilizers against oxygen, heat and ultraviolet rays, metal deterioration inhibitors, and hardening agents commonly used in the respective fields are used. Additives such as combustion agents, colorants, electrical property improvers, antistatic agents, lubricants, processability improvers, and tack improvers are added to the thermoplastic resin layer and the inorganic filler-containing olefinic polymer layer of the present invention. They may be added as long as they do not impair the properties of the composition. When blending the above additives into the thermoplastic resin and olefin polymer of the present invention, and when producing an inorganic filler-containing olefin polymer (including cases where the above additives are blended), it is common practice in each industry to It may be dry blended using a mixer such as a commonly used Henschel mixer, or may be obtained by melt kneading using a mixer such as a Banbury mixer, kneader, roll mill, or screw extruder. can. At this time, a homogeneous composition can be obtained by dry blending in advance and melt-kneading the resulting composition (mixture). In particular, it is preferable to use the olefinic polymer in the form of powder because it allows for more uniform mixing. In this case, the mixture is generally melt-kneaded and then formed into pellets, which are then subjected to the forming described later. In producing the inorganic filler-containing olefin polymer of the present invention, all the ingredients may be mixed at the same time, or some of the ingredients may be mixed in advance to produce a so-called masterbatch, and the resulting masterbatch and the remaining may be mixed with other ingredients. When melt-kneading is carried out in the production of the above blends, it must be carried out at a temperature higher than the melting point or softening point of the thermoplastic resin or olefinic polymer used. The system polymer deteriorates. For these reasons, the temperature is generally 20°C higher than the melting point or softening point of the respective thermoplastic resin or olefinic polymer (preferably,
(above 50°C), but within a temperature range that does not cause deterioration. (F) Manufacturing method of laminated metal foil In the present invention, a commonly practiced dry lamination method (extrusion lamination method) is applied as a method of laminating the thermoplastic resin layer and olefin polymer layer on the metal foil. This can be achieved by below,
The method will be explained in detail. The method of laminating (adhering) the thermoplastic resin layer with excellent weather resistance and the metal foil that is the metal layer can generally be carried out by a dry lamination method, but among thermoplastic resins, it is possible to It is possible to extrude. Also,
In the case of an olefin polymer, the thermoplastic resin layer and the metal foil can be laminated (adhered) by an extrusion lamination method. To produce laminated metal foil using the extrusion lamination method, a T-die film molding machine is used to form a thermoplastic resin layer at a resin temperature in the range of 240 to 370°C.Thermoplastic resin and olefin resin are used. The olefinic polymer forming the polymer layer may be extruded to the above-mentioned thickness, and at the same time, it may be bonded to the metal foil using a cooling pressure roll. When using thermoplastic resins and olefinic polymers that have excellent adhesion to metal foils, laminated metal foils can be produced as described above. However, if neither the thermoplastic resin nor the olefinic polymer has sufficient adhesion to the metal foil, a primer (anchor coating agent) commonly used in the field of thermoplastic resins may be used. ) is applied to one side of metal foil by gravure coating method or bar coating method and dried at 50 to 100°C.
Next, a thermoplastic resin film or sheet is pressed onto the surface of the metal foil primer using a pressure roll heated to 50 to 100°C. It can be obtained by laminating a film or sheet of an olefinic polymer on the other side of the metal foil laminated with the thermoplastic resin thus obtained, with a primer interposed therebetween. Alternatively, in contrast to this method, an olefin polymer film or sheet may be laminated on the metal foil with a primer interposed in advance, and a thermoplastic resin film or sheet may be laminated on the other side with a primer interposed. good. If one of the thermoplastic resins and olefinic polymers has sufficient adhesion to the metal foil, and the other is not satisfactory, use a material with sufficient adhesion in advance. A laminate of the film or sheet is produced by the extrusion lamination method without intervening a primer as described above on one side of the metal foil, and a primer is interposed on the other side of the metal foil of this laminate in the same manner as described above. Films or sheets that do not have sufficient adhesive properties may be laminated. Alternatively, a film or sheet with insufficient adhesion may be laminated on one side of the metal foil with a primer interposed in the same manner as described above, and a film or sheet with sufficient adhesion may be coated with a primer on the other side of the laminated metal foil. The adhesive may be bonded by the extrusion lamination method described above without intervening. The primer differs depending on the type of thermoplastic resin in the thermoplastic resin layer and the olefin polymer in the olefin polymer layer, but it is commonly used in each field, and there are aqueous and solvent-based primers. . The types include vinyl, acrylic, polyamide, epoxy, rubber, urethane, and titanium. The laminated metal foil (metal layer) produced in this manner will be explained with reference to FIG.
FIG. 1 is a partially enlarged sectional view of the laminated metal foil. In this drawing, A is a thermoplastic resin with excellent weather resistance, and B is a metal layer (metal foil). Further, C is an olefin polymer layer. Further, a and b are primer layers (a and/or b do not exist if either or one of the primers is not used). (G) Manufacture of reflector for circularly polarized antenna The thermoplastic resin of the laminated metal foil obtained as described above is placed on the moving side mold surface of the mold of an injection molding machine to form an olefin polymer layer. Attach it so that it faces the fixed side of the mold, and close the mold.
Next, the reflector plate for a circularly polarized antenna of the present invention can be manufactured by injection molding the inorganic filler-containing olefin polymer. At this time, the injection molding temperature is such that the resin temperature is higher than the melting point of the olefinic polymer containing an inorganic filler, but lower than the thermal decomposition temperature of the olefinic polymer. When using a propylene polymer as the olefin polymer, insert injection molding is
It is desirable to carry out at a temperature range of 170-290°C. On the other hand, when an ethylene polymer is used as the olefin polymer, insert injection molding is carried out at a temperature in the range of 120 to 250°C. In addition, if the injection pressure is 40 kg/cm ² or more at the gauge pressure at the nozzle of the cylinder of the injection molding machine, the inorganic filler-containing olefin polymer can be shaped into a shape almost similar to that of the mold. Not only that, but also a product with good appearance can be obtained. Injection pressure is generally 40-140Kg/ ^cm2 ,
In particular, 70 to 120 Kg/cm ² is desirable. (H) Reflector for circularly polarized antenna The reflector for circularly polarized antenna of the present invention obtained as described above will be explained below with reference to FIGS. 2 and 3. FIG. 1 is a partial perspective view of an antenna to which a reflector for a circularly polarized antenna is attached.
FIG. 2 is a sectional view of the reflector for the circularly polarized antenna. Moreover, FIG. 3 is a partially enlarged view of the cross-sectional view. In FIG. 1, is a reflector for a circularly polarized antenna of the present invention, and is a converter;
is the converter support rod, and is the reflector support rod. Also, is the wiring. Moreover, in FIGS. 3 and 4, 1 is a laminated metal foil. Furthermore, A is a thermoplastic resin layer with excellent weather resistance, and B is a metal foil. Further, C is an olefin polymer layer,
D is an inorganic filler-containing olefinic polymer layer in which an olefinic polymer is mixed. Furthermore, although a and b are primer layers, one or both may be absent. Furthermore, in order to attach the thus obtained reflector for a circularly polarized antenna to a support, a mounting rib may be provided so that it can be attached to the inorganic filler-containing olefin polymer layer, and the reflector may be reinforced. It is also possible to add reinforcing ribs for this purpose. Furthermore, it is also possible to drill holes in the circularly polarized antenna support obtained by the present invention and attach various support attachment parts using bolts, nuts, etc. In addition, the diameter of the reflector for the circularly polarized antenna is usually 60cm to 120cm.
cm. []Examples and Comparative Examples The present invention will now be explained in more detail with reference to Examples. In the Examples and Comparative Examples, the radio wave reflectance was measured as a microwave reflection coefficient based on the voltage standing wave ratio when a rectangular waveguide was used and the tip of the waveguide was short-circuited. In addition, the weather resistance test was conducted using a Sunshine Carbon Weather Meter, with a black panel temperature of 83°C and a due cycle of 12 minutes/12 minutes.
The surface appearance (adverse changes such as discoloration, fading, gloss change, crazing, blistering, peeling of metal foil, and cracks) after 2000 hours under the conditions of (60 minutes of irradiation) was evaluated.
In addition, heat cycle tests test samples at 80°C.
After 2 hours of exposure to temperature, the temperature was gradually cooled to -45°C over 4 hours, exposed to this temperature for 2 hours, and then gradually heated to 80°C over 4 hours, and the cycle continued.
After carrying out the test 100 times, the appearance of the surface of the sample was evaluated in the same manner as in the weather resistance test. Peel strength was determined by cutting a test piece with a width of 15 mm from a manufactured reflector for a circularly polarized antenna, and laminating the laminated metal foil at 180 degrees at a peeling speed of 50 mm/min in accordance with ASTM D-903. The strength was evaluated when it was peeled off. In this column of Table 1, "cohesive failure" refers to the fact that the adhesive strength between the laminated metal foil and the inorganic filler-containing olefinic polymer layer is too strong, causing the metal foil to break. Furthermore, the bending stiffness was measured according to ASTM D-790, and the coefficient of thermal expansion was measured according to ASTM D-696. The types and physical properties of the thermoplastic resin, olefin polymer, inorganic filler, and metal foil used in the thermoplastic resin layer in Examples and Comparative Examples are shown below. [(A) Thermoplastic resin] As a thermoplastic resin, polyvinylidene fluoride (hereinafter referred to as polyvinylidene fluoride) has a melt flow rate (measured according to ASTM D-1238 at a temperature of 250°C and a load of 10 kg) of 6.1 g/10 minutes. PVdF), a benzotriazole-based ultraviolet absorber.
Propylene homopolymer containing 0.4% and 0.5% by weight of carbon black [melt flow index (according to JIS K-6758, temperature
Measured at 230℃ and a load of 2.16Kg, hereinafter referred to as "MFI") is 0.5g/10 minutes, hereinafter referred to as "PP(A)"
[density 0.958 g/
cm ³ , melt index (measured according to JIS K-6760 at a temperature of 190°C and a load of 2.16 kg, hereinafter referred to as "MI") is 0.8 g/10 minutes, hereinafter referred to as "HDPE(1)". As a mixture, 20 parts by weight of chlorinated polyethylene (chlorine content 3.15% by weight, amorphous, molecular weight of raw material polyethylene approximately 200,000) having a Mooney viscosity (ML ₁₊₄ ) of 108 and 80 parts by weight of acrylonitrile Styrene copolymer resin (acrylonitrile content 23% by weight) and 2 parts by weight of dibutyl tin malate stabilizer [manufactured by Sankyoki Gosei Co., Ltd., trade name: Stann BM]
was kneaded for 10 minutes using a roll (surface temperature 180°C), and the resulting composition (hereinafter referred to as "ACS"), 20 parts by weight of dioctyl phthalate (as a plasticizer) and 5.0 parts by weight of dibutyltin maleate. (as a dehydrochlorination inhibitor) and 100 parts by weight of vinyl chloride homopolymer (degree of polymerization 1100, hereinafter referred to as "PVC") was used. [(B) Olefin polymer] As an olefin polymer, MFI is 2.0g/10
Propylene homopolymer [hereinafter referred to as “PP(B)”]
], propylene with an MFI of 15 g/10 min.
Ethylene block copolymer [ethylene content 15% by weight, hereinafter referred to as "PP(C)"], MI 0.8g/10
High-density ethylene homopolymer [density 0.950
g/cm ³ , hereinafter referred to as “HDPE(2)”] and MI
A high-density ethylene homopolymer [density 0.961 g/cm ³ , hereinafter referred to as "HDPE(3)"] with a density of 20 g/10 minutes was used. [(C) Inorganic filler] Inorganic fillers include talc with an average particle size of 3 microns (aspect ratio of about 7), mica with an average particle size of 3 microns (aspect ratio of about 8), glass fiber (single fiber diameter 11 microns, cut length 3
mm, hereinafter referred to as "GF"), and the average particle size is 0.8
Calcium carbonate (hereinafter referred to as "CaCO ₃ ")
) was used. [(D) Metal foil] Aluminum (hereinafter referred to as "Al"), copper, brass, and silver foils each having a thickness of about 20 microns were used. Examples 1 to 13, Comparative Examples 1 to 3 The thermoplastic resins, PP (B) and HDPE (2) were molded to produce films each having a thickness of 50 microns. In addition, an acrylic primer (manufactured by Showa Kobunshi Co., Ltd., trade name Vinyroll) was applied to one side of each metal foil.
92T) to a thickness of 20 microns on each surface, and urethane primer (manufactured by Toyo Morton Co., Ltd., trade name: Adcoat 335) to a thickness of 20 microns on each surface and dried. (In Examples 6 and 7, the urethane primer was applied to both sides). The thermoplastic resin film produced in this way (Comparative Example 1
A laminated metal foil was made by dry laminating a metal foil coated with a primer on both sides and an olefin polymer film (not used in Comparative Example 3). Manufactured. Furthermore, an inorganic filler and an olefin polymer (the types of each inorganic filler and olefin polymer and the content of the inorganic filler in the composition are shown in Table 1. (without any agent) were dry blended for 5 minutes using a Henschel mixer, and each mixture was used to produce a composition using a vented extruder at a resin temperature of 230°C. The thus produced laminated metal foil was inserted into a mold of an injection molding machine (mold clamping force: 1500 tons) so that the moving side mold surface (the olefin polymer layer was the fixed mold surface). After closing the mold, the injection pressure
Under the conditions of 80Kg/cm ² and resin temperature of 240℃, the first
The compositions whose types of olefinic resin and inorganic filler and the content of the inorganic fillers in the composition are shown in Table 1 were subjected to insert injection molding to form a circle having the same shape as in Example 1. We manufactured a reflector for polarized antennas. The elastic modulus and linear expansion coefficient of the inorganic filler-containing olefin polymer layer of each circularly polarized antenna reflector obtained as described above, and the peel strength of the metal foil from the inorganic filler-containing olefin polymer layer. measurements were carried out. The results are shown in Table 1.

[Table] When we measured the radio wave reflectance of each circularly polarized antenna reflector obtained as above, all of them were
It was 98%. Furthermore, a weather resistance test and a heat cycle test were conducted, and all of them except Comparative Example 1 showed discoloration, fading, change in gloss, crazing, etc.
No harmful changes such as blistering, peeling of the metal foil, or cracks were observed. However, in Comparative Example 1, the surface aluminum foil corroded.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view of a laminated metal foil. Furthermore, FIG. 2 is a partial perspective view of an antenna to which a typical reflector for a circularly polarized antenna manufactured according to the present invention is attached. Moreover, FIG. 3 is a sectional view of the reflector for the circularly polarized antenna. Furthermore, FIG. 4 is a partially enlarged view of the sectional view. A...Thermoplastic resin layer with excellent weather resistance, B...
...metal layer (metal foil), C...olefin polymer layer, a...primer layer, b...primer layer,
D... Inorganic filler-containing olefinic polymer layer mixed with olefinic polymer layer, 1... Laminated metal foil,... Reflection plate for circularly polarized antenna,... Converter,... Converter support Rod,...reflector support rod,...wiring.

Claims (1)

[Claims] 1 Using a metal foil laminated with a thermoplastic resin layer with excellent weather resistance on one side and an olefin polymer layer on the other side, the thermoplastic resin layer of the laminated metal foil is molded into an injection molding mold. The method is characterized in that the olefin polymer layer is attached to the movable mold surface of the mold so as to face the stationary mold side, and after the mold is closed, the inorganic filler-containing olefin polymer is injection molded. A method for manufacturing a reflector for a circularly polarized antenna.