JP2003019735A - Resin pipe manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure sufficient dimensional accuracy to a degree usable as the waveguide for the transfer device or common device of a microwave or milli- wave band transmitting-receiving antenna and to easily perform the elution work of a core. SOLUTION: A sodium hydrogencarbonate foaming agent is added to a water soluble polyvinyl alcohol resin to mold the core 10 and a liquid crystal polyester resin is injected in a cavity in such a state that the core 10 is arranged to mold a tubular resin molded article 20 having the core 10 arranged therein and the core 10 of the resin molded article 20 is eluted by water to obtain a resin waveguide 30 having high dimensional accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a resin tube, and is particularly suitable for use as a waveguide for a phase shifter or a duplexer of a microwave band transmission / reception antenna or a millimeter wave band transmission / reception antenna. The present invention relates to a method for manufacturing a resin pipe.

[0002]

2. Description of the Related Art As a conventional technique of this type, for example, there is one disclosed in JP-A-60-185404. That is, in this conventional technique, first, a core is formed from a metal such as an aluminum alloy, and a conductor layer is attached to the outer periphery of the core by electroplating. Next, the tubular body is molded by filling the outer periphery of the conductor layer with the resin for pipes while the core is placed inside the molding die. Finally, after releasing the cylindrical body, the core can be eluted by a chemical reaction or the like to obtain a resin tube having a desired shape.

According to such a conventional technique, since the core is made of metal, it is possible to secure a sufficiently high precision in its dimensions. Further, even when the pipe resin is filled in the molding die, there is no risk of the core being deformed by the filling pressure of the pipe resin.
As a result, it becomes possible to expect sufficient dimensional accuracy for the inner peripheral surface of the resin pipe molded using this core. Therefore, it becomes possible to use this resin tube as a waveguide for a transfer device or a waveguide for a duplexer of a microwave transmitting / receiving antenna or a millimeter wave transmitting / receiving antenna that requires high dimensional accuracy.

[0004]

By the way, in the above-mentioned prior art, since the core is formed of a metal such as an aluminum alloy, the work for eluting it is extremely complicated. In particular, if the resin pipe to be molded is bent or curved in the middle, the core cannot be pulled out in the middle, so it must be completely eluted, which requires an extremely long elution time. Become. Further, when the metal core is melted by a chemical reaction, there is a possibility that the material and shape of the resin pipe may be affected to some extent.

On the other hand, in the prior art, Japanese Patent Laid-Open No. 10-19
There is also provided a method for producing a resin molded product as disclosed in Japanese Patent No. 3387. That is, in this prior art, an oxyalkylene group-containing polyvinyl alcohol-based resin is applied as the core. According to this conventional technique, the polyvinyl alcohol resin containing an oxyalkylene group as a core exhibits water solubility. Therefore,
When the core is dissolved, water or hot water may be used, and the work can be performed very easily. Further, since water is used as the solvent, there is no fear of affecting the material and shape of the resin pipe.

[0006] However, in the core molded from the oxyalkylene-containing polyvinyl alcohol resin, the influence of sink marks and warpage cannot be ignored, and it is difficult to secure high dimensional accuracy. Further, when the pipe resin is filled in the state where it is placed inside the molding die, the core may be deformed due to the filling pressure of the pipe resin. For this reason, even with a resin tube molded using such a core, it is not possible to expect sufficient dimensional accuracy, and the above-mentioned microwave band transmission / reception antenna or millimeter wave band transmission / reception antenna transfer waveguide or shared It cannot be used as an instrumental waveguide.

The present invention has been made in view of the above circumstances, and is of a size sufficient to be used as a waveguide for a transfer device or a waveguide for a duplexer of a microwave band transmission / reception antenna or a millimeter wave band transmission / reception antenna. An object of the present invention is to obtain a method for manufacturing a resin pipe which can ensure accuracy and can easily perform core elution work.

[0008]

In order to achieve the above object, a method for producing a resin pipe according to the present invention is to add a foaming agent to a core resin which is soluble in a predetermined solvent to form a core. A core molding step of molding, a resin injection step of injecting a resin for pipes into a cavity in a state where the core is arranged to obtain a tubular resin molded product in which the core is arranged, and the resin molding A core elution step of eluting the core of the product with the solvent.

According to the present invention, the foaming pressure of the foaming agent added to the core resin prevents the core from sinking or warping,
The dimensional accuracy can be improved, and the amount of core resin to be eluted can be reduced.

A method of manufacturing a resin pipe according to the next invention is
In the above invention, water is used as the solvent.

According to the present invention, the core can be eluted by pouring water.

A method of manufacturing a resin pipe according to the next invention is
In the above invention, ultrasonic waves are applied to the solvent in the core elution step.

According to the present invention, the chemical reaction at the time of elution can be promoted.

A method of manufacturing a resin pipe according to the next invention is
In the above invention, the core molding step includes a step of insert-molding a reinforcing material into a soluble core resin.

According to the present invention, even when the resin for pipes is filled with the resin placed inside the molding die, there is no risk of the core being deformed by the filling pressure of the resin. Further, it is possible to reduce the amount of core resin to be eluted by the volume of the reinforcing material.

A method of manufacturing a resin pipe according to the next invention is
In the above invention, the core molding step includes a step of plating the outer surface of the core with metal.

According to the present invention, the metal plating applied to the core can be transferred to the inner peripheral surface of the resin pipe.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the method for producing a resin pipe according to the present invention will be described in detail below with reference to the accompanying drawings.

First, the resin tube manufactured according to the present invention is used as a waveguide in, for example, the phase shifter 2 or the duplexer 3 of the microwave transmitting / receiving antenna for the ground station of satellite communication shown in FIG. . The microwave transmitting / receiving antenna shown in FIG. 3 converts the parabolic antenna reflecting mirror 1 and the circular polarized wave reflected by the reflecting mirror 1 into a linear polarized wave, and also converts the linear polarized wave from the duplexer 3 into a circular polarized wave. 90 ° phase shifter 2, a duplexer 3 for both transmission and reception having a waveguide branched to divide an electromagnetic wave into a transmission wave and a reception wave depending on the frequency or phase, and a conductor propagating through the waveguide of the duplexer 3. TEM for microstrip lines of electromagnetic waves in the tube mode
The waveguide / coaxial conversion unit 4 is provided for converting the electromagnetic wave of the mode into the electromagnetic wave of the mode and the electromagnetic wave of the TEM mode from the microstrip line into the waveguide mode. The duplexer 3 has a built-in short-circuit plate (not shown) made of a metal plate.

Embodiment 1. 1 (a) to 1 (c)
FIG. 4 shows a method of manufacturing a resin waveguide which is Embodiment 1 of the present invention. In the first embodiment, first, as shown in FIG. 1A, a foaming agent is added to a water-soluble core resin to mold the core 10 by injection molding. The surface is plated with metal 11, specifically copper. Here, when injection molding is performed using the core 10 to which the foaming agent is added, the foaming agent causes a chemical reaction at the heating temperature during core molding and foams. Therefore, it becomes possible to effectively prevent sinking and warping of the core 10 by the foaming pressure of the foaming agent, and greatly improve the dimensional accuracy of the core 10 as compared with the core 10 simply molded of a resin material. Will be possible.

Next, the core 10 is placed in a metal mold for pipe molding, and from this state, a pipe resin (not water-soluble) is injected to the outer peripheral portion of the core 10. As shown in FIG. 1 (b), a tubular resin molded product 20 in which the core 10 is arranged is obtained.

Finally, if water or hot water is applied to the core 10, the core 10 will be eluted, as shown in FIG.
As shown in, the resin waveguide 30 having the metal plating 11 on the inner wall surface of the waveguide can be obtained. Here, as described above, the core 10 used in the present manufacturing method has high dimensional accuracy without sink marks or warpage. Therefore, this core 1
Even in the resin waveguide 30 molded using 0, high dimensional accuracy can be expected on the inner wall surface of the waveguide. Further, in the elution work of the core 10, simply water,
Alternatively, since it suffices to apply hot water, the work can be performed extremely easily and the resin waveguide 30
There is no fear of affecting the material or shape of the resin molded product 20 that will be the outer skin of the product. Furthermore, the foamed core 10
Since an innumerable number of cavities are formed therein, the amount of core resin to be substantially eluted becomes small.
Furthermore, by irradiating the water, which is the solvent, or hot water with ultrasonic waves, the chemical reaction at the time of elution is promoted. As a result, it becomes possible to shorten the elution work time of the core 10 and further facilitate the work. The first embodiment
Since the metal plating 11 is applied to the outer surface of the core 10, the step of plating after molding the resin waveguide 30 is unnecessary, but the metal plating 11 is not necessarily applied to the outer surface of the core 10. It is not necessary to apply the metal plating, and the metal plating 11 may be applied to the inner surface of the waveguide after molding the resin waveguide 30.

Embodiment 2. 2 (a) to 2 (c)
FIG. 5 shows a method for manufacturing a resin waveguide which is the second embodiment of the present invention. In the second embodiment, first, as shown in FIG. 2A, the reinforcing metal fitting 12 is insert-molded by performing injection molding using a water-soluble core resin having a foaming agent added. Get the child 10. Also in this case, as in Embodiment 1, the foaming agent causes a chemical reaction at the heating temperature during core molding to foam during injection molding. Therefore, it becomes possible to effectively prevent sinking and warping of the core 10 by the foaming pressure of the foaming agent, and greatly improve the dimensional accuracy of the core 10 as compared with the core 10 simply molded of a resin material. Will be possible. It is the same as in the first embodiment that the outer surface of the core 10 is preferably plated with a metal 11 such as copper.

Next, the core 10 is placed in a metal mold for pipe molding, and from this state, a pipe resin (not water-soluble) is injected to the outer peripheral portion of the core 10. As shown in FIG. 2B, a tubular resin molded product 20 in which the core 10 is arranged is obtained. Here, in the core 10 in which the reinforcing metal fitting 12 is insert-molded as described above, there is no risk of deformation due to the injection pressure of the pipe resin when the pipe resin is injected, and the desired shape is maintained. Like

Finally, if water or hot water is applied to the core 10, the core 10 is eluted, and after the core 10 is eluted, the reinforcing metal member 12 can be pulled out, as shown in FIG. As shown in (), the resin waveguide 30 having the metal plating 11 on the inner wall surface of the waveguide can be obtained.
Here, as described above, the core 10 used in the present manufacturing method.
Has high dimensional accuracy without sink marks or warpage. Moreover, the desired shape is maintained even when the pipe resin is injected. Therefore, even in the resin waveguide 30 formed by using the core 10, it is possible to expect high dimensional accuracy on the inner wall surface of the waveguide. Also, the core 1
In the elution work of 0, since it is sufficient to simply pull out the reinforcing metal fitting 12 after applying water or hot water, the work can be carried out very easily, and the resin which becomes the outer skin of the resin waveguide 30 can be obtained. There is no risk of affecting the material or shape of the molded product 20. Further, since the foamed core 10 has an innumerable number of cavities formed therein, and further, since the reinforcing metal fitting 12 is insert-molded inside, the core core 10 to be substantially eluted should be used. The amount of resin is smaller than that in the first embodiment. Also, by irradiating the water or hot water as a solvent with ultrasonic waves, the chemical reaction at the time of elution is promoted. As a result, it is possible to significantly shorten the elution work time of the core 10 and to further facilitate the work. Note that, also in the second embodiment, since the metal plating 11 is applied to the outer surface of the core 10, the step of plating after molding the resin waveguide 30 is not necessary, but the core 10 is not necessarily required. Metal plating on outer surface 11
It is not necessary to apply the metal plating 11, and the metal plating 11 may be applied to the inner surface of the waveguide after the resin waveguide 30 is molded.

Although the above-described first and second embodiments exemplify the method of manufacturing each tubular waveguide, it is of course applicable to the case of manufacturing a cylindrical waveguide. It is possible. Although water is used as the solvent, an organic solvent may be used.

Specific examples of the present invention will be described below.

(Example 1) As a water-soluble resin for cores, a polyvinyl alcohol resin (Kuraray's Poval) was used.
CP-1000) was used, and a sodium hydrogencarbonate foaming agent (Cerbon SC-K manufactured by Eiwa Chemical Industry Co., Ltd.) was used as a foaming agent to be added thereto to mold a core by injection molding. The sodium hydrogencarbonate foaming agent added to the polyvinyl alcohol resin is 1 to 10% by weight. The resin containing the foaming agent was injected into a core molding die maintained at 30 ° C. at a temperature of 180 ° C. and an injection pressure of 80 MPa to obtain a core.

The core is set in a waveguide molding die,
Liquid crystal polyester resin (polyplastics, Vectra C8) with good adhesion to plating and excellent precision moldability
Insert molding was performed in 10). Then, water or hot water was applied to the core of the insert-molded product to elute the core to form a waveguide. After that, metal plating was applied to the inner peripheral surface of the waveguide to obtain a waveguide having a desired dimensional accuracy. In the above-described manufacturing method, the insert molded product was immersed in water or hot water irradiated with ultrasonic waves of 50 kHz in an ultrasonic cleaning device to elute the core, thereby significantly shortening the elution time.

In the above-mentioned manufacturing method, even if ammonium carbonate, ammonium bicarbonate, sodium nitrite, azide compound, or sodium borohydride is used as the inorganic chemical foaming agent, the sink marks and sleds of the core are caused by the foaming pressure. It can be effectively prevented, and the dimensional accuracy can be greatly improved.

(Example 2) As a water-soluble core resin, a polyvinyl alcohol resin (Kuraray's Poval) was used.
CP-1000) was used, and a diazo compound foaming agent (Vinihol SW # 7 manufactured by Eiwa Chemical Industry Co., Ltd.) was used as a foaming agent to be added thereto to mold a core by injection molding. The diazo compound foaming agent added to the polyvinyl alcohol resin is 1 to 10% by weight. The resin added with this foaming agent is at a temperature of 180 ° C. and an injection pressure of 80 MPa.
Then, a core was obtained by injecting into a core molding die maintained at 30 ° C.

This core is set in a waveguide molding die,
Liquid crystal polyester resin (polyplastics, Vectra C8) with good adhesion to plating and excellent precision moldability
Insert molding was performed in 10). Then, water or hot water was applied to the core of the insert-molded product to elute the core to form a waveguide. After that, metal plating was applied to the inner peripheral surface of the waveguide to obtain a waveguide having a desired dimensional accuracy.

In the above-mentioned manufacturing method, even if a nitroso compound or a sulfonylhydrazide compound is used as the organic chemical foaming agent, sinking or warping of the core can be effectively prevented by the foaming pressure, and the dimensional accuracy thereof can be improved. It has become possible to greatly improve.

Example 3 As a water-soluble core resin, a polyvinyl alcohol resin (Kuraray's Poval) was used.
CP-1000), and after melting this, 80
A core was molded by filling a carbon dioxide gas in a supercritical state at 100 ° C at 100 ° C and performing injection molding.

This core is set in a waveguide molding die,
Liquid crystal polyester resin (polyplastics, Vectra C8) with good adhesion to plating and excellent precision moldability
Insert molding was performed in 10). Then, water or hot water was applied to the core of the insert-molded product to elute the core to form a waveguide. After that, metal plating was applied to the inner peripheral surface of the waveguide to obtain a waveguide having a desired dimensional accuracy. In the above-described manufacturing method, the insert molded product was immersed in water or hot water irradiated with ultrasonic waves of 50 kHz in an ultrasonic cleaning device to elute the core, thereby significantly shortening the elution time.

In the above-mentioned manufacturing method, even if nitrogen gas is used as the inorganic physical foaming agent, sinking and warping of the core can be effectively prevented by the foaming pressure, and the dimensional accuracy thereof is greatly improved. It has become possible.

[0037]

As described above, according to the present invention, sinking or warping of the core can be prevented by the foaming pressure of the foaming agent added to the core resin, and its dimensional accuracy can be improved. Therefore, it is possible to improve the dimensional accuracy of the resin pipe molded using this core. Moreover, in the foamed core, the amount of the core resin to be eluted is reduced, so that the elution time can be shortened and the operation can be facilitated.

According to the next invention, since the core can be eluted by pouring water, there is no fear of affecting the material and shape of the molded resin pipe.

According to the next invention, since the chemical reaction at the time of elution can be promoted, the elution time can be shortened.

According to the next invention, even when the resin for pipes is filled in the state of being arranged inside the molding die, there is no possibility that the core will be deformed by the filling pressure of the resin, so that the resin molding pipe It is possible to further improve the dimensional accuracy of. Further, since the amount of the core resin to be eluted can be reduced by the volume of the reinforcing material, the core elution time can be further shortened.

According to the next invention, since the metal plating applied to the core can be transferred to the inner peripheral surface of the resin tube, when the resin tube is used as a waveguide, the inner wall surface is separately plated. Since it is not necessary to apply it, the waveguide manufacturing method can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view sequentially showing a method of manufacturing a resin pipe according to a first embodiment of the present invention.

FIG. 2 is a sectional view sequentially showing a method of manufacturing a resin pipe which is Embodiment 2 of the present invention.

FIG. 3 is a block diagram showing a microwave transmitting / receiving antenna in which a resin tube molded according to the present invention is applied as a waveguide for a transporter or a waveguide for a duplexer.

[Explanation of symbols]

1 reflector, 2 phase shifter, 3 duplexer, 4 waveguide / coaxial converter, 10 core, 11 metal plating, 12 reinforcing metal fittings, 20 resin molded product, 30 resin waveguide.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29L 23:00 B29L 23:00 (72) Inventor Naoshi Yamada 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanrishi Electric Machinery Co., Ltd. (72) Inventor Hideki Asao 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd. (72) Inventor Kazuhisa Itami 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd. In-house F-term (reference) 4F202 AG08 AJ03 CA11 CB01 CD01 CD22 CD30 CK81 CM27 5J014 DA03 DA04

Claims (5)

[Claims] 1. A core molding step of molding a core by adding a foaming agent to a core resin that is soluble in a predetermined solvent, and injecting a pipe resin into a cavity with the core arranged. By so doing, a resin injection step of obtaining a tubular resin molded product in which the core is arranged, and a core elution step of eluting the core of the resin molded product with the solvent are included. Method for producing a resin pipe to be used. 2. The method for producing a resin pipe according to claim 1, wherein water is used as the solvent. 3. The method for producing a resin pipe according to claim 1, wherein the solvent is irradiated with ultrasonic waves in the core elution step. 4. The resin pipe manufacturing method according to claim 1, wherein the core molding step includes a step of insert-molding a reinforcing material into a soluble core resin. Method. 5. The method of manufacturing a resin pipe according to claim 1, wherein the core molding step includes a step of plating the outer surface of the core with metal.