JPS60246104A - Cylindrical radio wave reflecting tube - Google Patents

Abstract

PURPOSE:To obtain a reflecting tube having excellent corrosion resistance and whose radio wave transmitting characteristic is unchanged for a long period by forming the reflecting tube that a coating film with excellent weather resistance, the metallic layer and the olefinic polymer layer are laminated sequentially. CONSTITUTION:The thickness of the coating film layer with excellent weather resistance being an inner layer is 5mu-1mm., the thickness of the metallic layer being an intermediate layer is 5mu-1mm., and the thickness of the olefinic polymer layer being an outer layer is 0.5mm.-15mm.. As a typical example of a paint 1, an unsaturated or a saturated polyester resin group paint is used. As a typical example of a metal 2, a metal simple substance or an alloy such as aluminum, iron, copper or zinc is used. As the olefinic polymer 3, ethylene homopolymer, a propylene homopolymer, or an ethylene and propylene copolymer is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [I] Object of the Invention The present invention relates to a cylindrical radio wave reflecting tube having a metal layer as an intermediate layer. More specifically, it is a cylindrical radio wave reflecting tube formed by sequentially laminating at least (A) a coating layer with excellent weather resistance, (B) a metal layer, and (C) an olefin polymer layer, and the inner layer is a weather resistant The thickness of the coating layer with excellent properties is 5 microns to 1 fl 1 m, and the thickness of the intermediate metal layer is 5 microns to 1 fl 1 m.
The invention relates to a cylindrical radio wave reflecting tube characterized in that the thickness of the olefin polymer layer as the outer layer is 0.5 m+e to 15 mm, and the metal layer as the intermediate layer is The purpose of this invention is to provide a waveguide that reflects .

[II] Background of the Invention Conventionally, pipes or pipe-shaped nets made of metal such as aluminum or copper have been used as waveguides for radio waves. However, since metals corrode, it is necessary to make them into anti-corrosive alloys or apply anti-corrosive coatings. However, anti-corrosion alloys are expensive. In addition, with regard to anti-corrosive coating, it is necessary to apply the coating several times in order to achieve complete corrosion protection, which not only ends up being expensive, but even if it is applied several times, it will take a long time. Corrosion progresses gradually with use. Furthermore, attempts have been made to fabricate waveguides using various thermoplastic resins or thermosetting resins that are free from corrosion and by notarizing the inner surface using electroless plating or the like. However, it is difficult to manufacture the inner reflective layer uniformly and without loss of radio waves, and it is also difficult to prevent corrosion of the inner metallized layer. Attempts have also been made to mold pipes and create waveguides by filling various thermoplastic resins or thermosetting resins with metal powder, carbon black, carbon fiber, etc., but this has resulted in large radio wave losses. It is difficult to make the inner surface smooth, and it has not been possible to obtain a waveguide that can withstand long-term use and has no radio wave transmission loss.

[m] Structure of the invention Based on the above, the present inventors have obtained a cylindrical radio wave reflecting tube that has a simple manufacturing process, has radio wave reflecting ability, and can maintain its performance for a long period of time. This is the result of various searches regarding this matter.

At least (A) a coating layer with excellent weatherability, (B) a metal layer, and (C) an olefin polymer layer.

It is a cylindrical radio wave reflecting tube made by sequentially laminating layers, and the inner layer, a coating layer with excellent weather resistance, has a thickness of 5 microns to 1 micron.
mm, and the thickness of the intermediate metal layer is 5 μm to 1 μm.

And the thickness of the outer olefin polymer layer is 0.5■
It has been discovered that a cylindrical radio wave reflecting tube characterized by a diameter of 15II to 15II11 has a relatively simple manufacturing process, good durability, and excellent radio wave transmission characteristics, and the present invention has been made based on the present invention. reached.

[IV] Effects of the invention The cylindrical radio wave reflecting tube of the invention exhibits the following effects (features) including its manufacturing process.

(1) Due to its excellent corrosion resistance, there is no change in radio wave transmission characteristics over a long period of time.

(2) The reflecting tube is lightweight and does not deform even under local external pressure.

(3) It is possible to form the metal layer uniformly,
In addition, since it is possible to manufacture a laminate without scratches or wrinkles on the metal layer, there is no uneven reflection of radio waves.

(4) The olefin polymer used can be easily formed into various complex shapes, so it can be used in places where good appearance and functionality such as installation are required.

(6) The cylindrical radio wave reflecting tube (cylindrical laminate molded product) has excellent mechanical strength (rigidity, creep deformability) and can be used as a structure.

The cylindrical radio wave reflecting tube obtained by the present invention can be used in a wide variety of ways to achieve the following effects. Typical applications include various parts in applied technology fields that utilize microwaves, such as parabolic antennas, radar, and microwave ovens.

[V] Detailed Description of the Invention (A) Paint The paint used to manufacture the metal layer having a coating layer with good weather resistance of the present invention is widely produced industrially and is used in many ways as a paint for metals. It has been used for a long time. The manufacturing method and various physical properties of these paints are well known.1. +. These paints are classified into solvent type using organic solvents such as toluene and xylene, aqueous emulsion type, and solvent-free type, but any type of paint can be selected depending on the coating method. Typical of these paints are:
Unsaturated or saturated polyester resin paints, polyurethane resin paints obtained by reacting polyester polyols, polyether polyols or polyurethane polyols with diisocyanates, aminoalkyd resin paints, acrylic resin paints, melamine resin paints, cyano Acrylate resin paint, epoxy resin paint, silicone resin paint, organic titanate paint,
Vinyl chloride resin paint, acrylic urethane resin paint,
Examples include amide resin-based paints and fluorine-containing resin-based paints such as vinylidene fluoride resin. Furthermore, additives such as a matting agent such as silicic acid, a coloring agent such as tF48 and dye, an antioxidant, and an ultraviolet absorber can be added to these paints. Among the above paints, polyurethane resin paints, acrylic resin paints, epoxy resin paints, aminoalkynode resin paints, and vinylidene fluoride resin paints are preferred because of their excellent weather resistance. Particularly, by incorporating an antioxidant and an ultraviolet absorber into the paint of the present invention, a paint with good weather resistance can be obtained, which is suitable.

(B) Metal 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 These metals do not require surface treatment and are chemically treated in advance.

It may be surface-treated such as plating, and it may also be preferably painted or printed.

(C) Olefin polymer The olefin polymer used for manufacturing the outer layer of the cylindrical radio wave reflecting tube in the present invention may also be an ethylene homopolymer, a propylene homopolymer, or a copolymer of ethylene and propylene. Copolymers of ethylene and/or propylene with other α-olefins having at most 12 carbon atoms (the copolymerization ratio of α-olefins is at most 20
Weight %) force ζ can be raised. The melt index (measured according to JIS K-El?EiO at a temperature of 190°C and a load of 2.18 kg, hereinafter referred to as rM, 1.) or melt flow index (JIS K-El?EiO) of these olefin polymers -8758,
Measured at a temperature of 230°C and a load of 2.18 kg, hereinafter referred to as r MFIJ) is 0.01 to 100 g/
10 minutes is preferable, especially 0.02 to 80 g/
A time of 10 minutes is preferred. M, 1. or III
If an olefin polymer with an FI of less than 0.01 g/10 minutes is used, the formability of the cylindrical laminate molded product will be poor, unevenness will occur on the surface, and it will be difficult to form a uniform molded product. difficult to obtain. On the other hand, when an olefin polymer with a weight exceeding 100 g/10 minutes is used, moldability is excellent, but the mechanical properties of the resulting molded product are poor. Sarani, low density (0,900 g/cm') and high density (0,1180 g/cm') ethylene homopolymer or copolymer of ethylene with a small amount of the above α-olefins, or propylene homopolymer Random or pro-quench copolymers of propylene and ethylene and/or other alpha-olefins are preferred.

These olefinic polymers are obtained 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) mixed with a dielectric substance (e.g., silica). It can also be obtained by homopolymerization or copolymerization of olefins with a catalyst system (so-called Phillips catalyst) or using a radical initiator (for example, an organic peroxide).

Furthermore, in the present invention, a modified boron olefin obtained by graft polymerizing a compound having at least one double bond (for example, an unsaturated carboxylic acid, a monocarboxylic acid, or a vinyl silane compound) to these olefin polymers is used. It is also built.

Regarding these olefin polymers and modified polyolefins, their manufacturing methods are described below.

These olefin polymers and modified polyolefins may be used alone or in combination of two or more. Two or more of these olefin polymers and modified polyolefins may be resin blended in any proportion.

Furthermore, various inorganic fillers can be added to the olefin polymer used as the outer layer of the cylindrical radio wave reflecting tube of the present invention in order to reduce the coefficient of linear expansion of the olefin polymer layer. The inorganic fillers used to produce the olefinic polymer layer containing inorganic fillers are generally those widely used in the field of synthetic resins and GoJ. 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. White lead oxide, magnesium carbonate, calcium carbonate, basic magnesium carbonate, white carbon, asbestos, mica, talc, glass fiber, glass powder, glass peas, clay, diatomaceous earth, silica, wollastonite, iron oxide, Examples include antimony oxide, titanium oxide (titania), lithopone, pumice powder, aluminum sulfate (gypsum, etc.), silica-resistant zirconium, zirconium oxide, barium carbonate, 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 IJ, below). In the case of fibrous materials, the diameter is 1 to 500 microns (preferably 1 to 300 microns) and the length is 0.1 microns.
~611m1 (suitably 0.1~5a+m2) is desirable. Further, the diameter of the flat plate is 2 mm or less (preferably 1 mm or less). (D) 8-layer structure (1) Inner layer (coating layer with excellent weather resistance) The cylindrical shape of the present invention The coating that makes up the inner layer of the radio wave reflecting tube! i! The layer serves to prevent corrosion of the metal layer from occurring. From this, the thickness is 5 microns to lam, preferably 10 microns to 0.5 mm, and particularly preferably 10 microns to OJ+em. The thickness of this coating layer is 5
If it is less than a micron, not only will the metal layer corrode, but it will also cause corrosion due to contact and friction with other items during use.
There is a problem in that the metal layer may become loose due to wear. 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 Furthermore, the metal layer of the present invention serves to reflect radio waves. The thickness of this metal layer is between 5 microns and 1 mm.
and preferably 5 to 500 microns, especially 1
0-500 microns is preferred. The thickness of the metal layer is 5
At less than micron, cylindrical radio wave reflecting tube is used as IJ! ! During manufacturing, wrinkles and creases are likely to occur in the metal layer.
There are problems with appearance and performance H. On the other hand, if it exceeds 1 ane, not only will the weight increase, but also the cost will increase, and furthermore, it will cause problems when bending or bending the cylindrical radio wave reflecting tube.

(3) Outer layer (olefin polymer layer) Furthermore, the olefin polymer layer constituting the outer layer of the uninvented cylindrical radio wave reflecting tube may be composed only of the olefin polymer, or the inorganic It is also possible to further incorporate fillers. When adding an inorganic filler,
The blending ratio (composition ratio) of the inorganic filler is at most 80% by weight (that is, the composition ratio of the olefin polymer is at least 20% by weight), preferably 70% by weight or less,
Particularly suitable is 60% by weight or less. If the composition ratio (content) of the inorganic filler in this layer exceeds 80% by weight, it will be difficult to produce a uniform composition, and even if a uniform composition can be obtained, it will be discussed later. When manufacturing cylindrical radio wave reflecting tubes by sheet manufacturing or injection molding, it is not possible to obtain a good product (cylindrical radio wave reflecting tube).

The thickness of this olefinic polymer layer is 500 microns to 151111, preferably 1 to 10 IIIm,
Especially 1~? mm is preferred. If the thickness of the olefinic polymer layer constituting the outer layer is less than 500 micrometers, it is not desirable because it lacks rigidity and may be deformed or damaged by external force. On the other hand, 151! If it exceeds II+, 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-1-.

In manufacturing the olefin polymer layer that constitutes the outer layer, we use stabilizers against oxygen, heat and ultraviolet rays, metal deterioration inhibitors, flame retardants, and colorants that are commonly used in each field of olefin polymers. , an electrical property improver, an antistatic agent, a lubricant, a processability improver, and an adhesion improver without impairing the properties of the composition of the olefinic polymer layer constituting the outer layer of the present invention. It may be added within a range.

When producing the olefin polymer constituting the outer layer of the present invention (including the case in which the additives mentioned above are mixed), a mixer such as a Henschel mixer, which is commonly used in the olefin polymer industry, is used. They may be triblended and can be obtained by melt-kneading using mixers such as pan/Heary mixers, kneaders, roll mills and single screw extruders. At this time, the composition (mixture) obtained by tri-blending in advance
A homogeneous composition can be obtained by melt-kneading.

In particular, it is preferable to use the olefin polymer in the form of powder because it allows for more uniform mixing.

In this case, the mixture is generally melt-kneaded, then molded into pellets, and subjected to the molding described later.

In producing the olefinic polymer containing an inorganic filler to produce the outer layer of the present invention, all of the ingredients may be mixed at the same time, or some of the ingredients may be mixed in advance to form a so-called master bath. may be prepared, and the resulting master patch and the remaining formulation components may be mixed.

When melt-kneading is performed to produce the above-mentioned blend, it must be carried out at a temperature higher than the melting point or softening point of the olefinic polymer used; however, if carried out at high temperatures, the olefinic polymer will deteriorate. For these reasons, it is generally 20% lower than the melting point or softening point of the olefin polymer.
C. (preferably higher than 50.degree. C.), but within a temperature range that does not cause deterioration.

(E) Cylindrical radio wave reflecting tube The inner diameter of the cylindrical radio wave reflecting tube obtained by the present invention varies depending on the frequency band of the transmitted radio wave, but is at least 1.
111 is common. If the inner diameter of the cylindrical radio wave reflecting tube is less than 1 mm, the frequency range is too high to be practical.

As described above, the cylindrical radio wave reflecting tube of the present invention is composed of (A) a coating layer with excellent weather resistance as an inner layer, (B) a metal layer as an intermediate layer, and (C) an olefin polymer layer as an outer layer. be. This reflecting tube will be explained in more detail with reference to FIG. FIG. 1 is an enlarged sectional view of the cylindrical radio wave reflecting tube of the present invention. In this figure, numeral 1 is the inner layer, which is a coated N coating layer with excellent weather resistance. 2 is a metal layer which is an intermediate layer.

Further, 3 is an olefin polymer layer which is an outer layer.

As described above, the cylindrical radio wave reflecting tube of the present invention has a coating layer (1) with excellent weather resistance as an inner layer, and a metal layer (1) as an intermediate layer.
2) and an olefin polymer layer (3) as an outer layer. If the metal layer and the inner coating film layer have good adhesion, and the metal layer and the outer olefin polymer layer have good adhesion, they may be left in close contact with each other, but if the adhesion is poor, In order to maintain sufficient adhesion (adhesion) between them, a primer and an adhesive such as an olefinic polymer grafted with an unsaturated carboxylic acid or its anhydride may be interposed.

(E) Method for manufacturing cylindrical radio wave reflecting tube There are various methods for manufacturing the cylindrical radio wave reflecting tube of the present invention. Typical examples of this method include applying an adhesion agent to one side of the metal layer in advance and extrusion laminating a coating layer with excellent weather resistance. The coating layer with excellent weather resistance is press-molded and shaped into a cylindrical shape so that the coating layer with excellent weather resistance is on the inner surface.The obtained cylindrical laminate is coated with an olefin polymer layer as shown below. It may be laminated. At this time, if the adhesion between the olefin polymer layer and the metal layer is good, no adhesion agent is applied to the metal layer.
A laminate may also be produced by direct extrusion lamination or press molding.

After shaping the laminate thus obtained into a cylindrical shape so that the coating layer with excellent weather resistance is on the inner layer, the outer layer of the cylindrical metal layer is laminated with the olefin polymer layer. The other side of the laminate may be coated with an adhesion agent in advance, and the olefin polymer layer may be extruded, spiral-wound, or circular die coated. It can also be manufactured by inserting the olefin polymer into the mold and injection molding the olefin polymer. In any of these methods, if the adhesion between the metal layer and the olefin polymer layer is excellent, the metal layer can be formed into a cylindrical laminate without applying an adhesion agent. A product (cylindrical radio wave reflecting tube) may also be manufactured. None of the above-mentioned extrusion spiral wind method, round guid coat method, and insert injection molding method is unique to the present invention, and any commonly used method may be applied. When heating in these methods, it goes without saying that the heating must be carried out within a temperature range in which the olefin polymer used does not undergo thermal deterioration. The methods for manufacturing these laminates are merely some examples, and other methods may be applied.

[VI] Examples and Comparative Examples The present invention will be explained in more detail with reference to Examples below.

In the Examples and Comparative Examples, the radio wave reflectance was measured as a microwave reflection coefficient using a circular waveguide and a voltage standing wave ratio when using the cylindrical radio wave reflecting tube of the present invention. In addition, the salt spray test follows JIS.
The appearance of the metal layer surface (discoloration, fading, gloss change, crazing, blistering, peeling of metal foil, cracking, and other harmful changes) was observed using a saline solution, and evaluation was made based on the time at which harmful changes occurred. Furthermore, a heat cycle test tested the sample at 80°C.
After being exposed to for 2 hours, it 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 after repeating this cycle 100 times. The appearance of the surface of the sample was evaluated in the same manner as in the above-mentioned Takashiko salt spray test. In addition, the bending rigidity is ASTI
Measured according to ID-790.

The types and physical properties of the olefin polymers, coating layers with excellent weather resistance, inorganic fillers and metal foils used in Examples and Comparative Examples are shown below.

[(A) Paint] Two-component fluororesin (manufactured by Dainippon Toyo Co., Ltd., product name: V-Flon, hereinafter referred to as "F paint") and two-component polyurethane resin (manufactured by Nippon Oil Co., Ltd., product name: Hi-Flyon) were used as paints. Urethane (hereinafter referred to as "U paint") was used.

((B) Olefin polymer) In order to produce the inner layer and outer layer of the present invention, a propylene homopolymer [melt flow index (according to JIS K-13758, temperature is 230°C and load is 2 .Measured under the condition of 16 kg, hereinafter referred to as rMFIJ) is 0.5g710 minutes, hereinafter referred to as rP
P(a) J], high density polyethylene [density 0
, 958 g/cm', melt index (,
JIS K-El? 60, measured at a temperature of 190°C and a load of 2.16 kg, hereinafter rl11.
1. J) is 0.8g/10 minutes, hereinafter r) IDP
E(1) J], MFI is 0. '1g710
Propylene-ethylene block copolymer (ethylene content 10.5% by weight, hereinafter referred to as rPP(B)J) with a weight ratio of 20 g/10 min, a high-density ethylene-Ni autopolymer (density 0.981g/c
rn', hereinafter referred to as ``IDPE(2)'') was used.

C) Inorganic fillers] As inorganic fillers, 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, force/length 3mm, hereinafter r
GFJ) and calcium carbonate (hereinafter referred to as rCaCO5J) having an average particle size of 0.8 microns were used.

[(C) Metal foil] Aluminum foil each having a thickness of about 20 microns (
(hereinafter referred to as "A9"), copper and brass foils were used.

Examples 1 to 9, Comparative Examples 1 and 2 An epoxy resin primer (manufactured by Dainippon Toyo Co., Ltd., trade name: V-Fron Primer) was applied to one side of the metal foil whose type is shown in Table 1. It was coated to a thickness of 20 microns and dried.

The primer-coated surface of the obtained metal foil was coated with a paint whose type is shown in Table 1 (U paint for Example 6, F paint # for the others).
4) was applied to a dry thickness of 30 microns and left overnight. 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. In Comparative Example 2, the inorganic filler (without blending) were tri-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. Each of the obtained compositions (pellets) or olefin polymers was
- A 2 mi thick sort was produced using a gouy molding machine.

The metal foil having the coating layer obtained as described above was
Cut into cm pieces with a diameter of 50 mm and a length of 30 cm at 70°C.
The foil was wrapped around a heated aluminum acid mandrel and then seamed to produce a cylindrical metal foil with a length of 30 cm. A urethane primer (manufactured by Toyo Morton Co., Ltd., trade name Adko 335) was applied to the outer surface of the cylindrical metal foil wrapped around the obtained mandrel so that the dry thickness was 30 microns, and dried. . The obtained cylindrical metal laminate coated with an outer surface primer was extruded by the spiral winding method (Examples 1 and 3.4), the round coating method (Example 2), and the insert injection molding method (Example 2).
5-7, Comparative Examples Cylindrical radio wave reflecting tubes were manufactured according to 1.2). The bending strength and salt water corrosion test of the cylindrical radio wave reflecting tube thus obtained were measured. The results are shown in Table 1.

When the radio wave conductivity of each cylindrical radio wave reflecting tube thus obtained was measured, it was 96% in all cases.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a cylindrical radio wave reflecting tube of the present invention. l... Inner layer, coating layer with excellent weather resistance, 2...
Metal foil as an intermediate layer; 3. Olefin polymer layer as an outer layer.Patent applicant
Showa'wt Co., Ltd. Representative Patent Attorney Sei Kikuchi

Claims (1)

[Claims] A cylindrical radio wave reflecting tube formed by sequentially laminating at least (A) a coating layer with excellent weather resistance, (B) a metal layer, and (C) an olefin polymer layer, the inner layer being The thickness of the coating layer with excellent weather resistance is 5 microns to 1
A cylindrical radio wave reflecting device characterized in that the thickness of the metal layer as the intermediate layer is 5 μm to lem, and the thickness of the olefin polymer layer as the outer layer is 0.5 m+o to 15 mm. tube.