JP2006196209A - Coaxial cable and insulated cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coaxial cable in which copper induced degradation caused by contact of an insulating body and a copper conductive body can be prevented. <P>SOLUTION: In the coaxial cable 10 composed of an internal conductor 11 of the center, the insulator 12 of polypropylene or a polypropylene based resin (its polymer, resin composition containing polypropylene, or these foamed body), an external conductor 13, and a sheath 14, because a copper inhibiting layer is made to be interposed at least between the internal conductor 11 and the insulator 12, and between the insulator 12 and the external conductor 13, basically the insulator and a copper conductor is separated by the copper inhibiting layer, and a superior copper inhibiting effect can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coaxial cable and an insulated cable that prevent copper damage caused by contact between an insulator and a copper conductor.

  For example, a coaxial cable using polypropylene as an insulator has been conventionally proposed. Such a coaxial cable is shown in FIG. 3, as shown in FIG. 3, a central inner conductor 1 made of a copper twisted wire conductor, an insulator 2 made of a polypropylene coating layer, an outer conductor 3 made of a copper twisted wire braid, and an outermost layer. The sheath 4 made of PVC or the like is used.

  In the case of this polypropylene, its polymer, polypropylene-containing resin composition, or these foams (hereinafter abbreviated as polypropylene resin), polyethylene or polyethylene resin (polyethylene polymer, polypropylene-containing resin composition, Or, these cables are lighter and have higher heat resistance, strength, and rigidity, so that an excellent cable can be obtained depending on applications.

  However, in the case of a cable using such polypropylene or polypropylene resin as an insulator, when the insulator and a conductor, that is, a copper conductor are in contact with each other, particularly at a high temperature, the insulator resin reacts with copper to form a complex, It is known that a degradation phenomenon that decomposes (hereinafter abbreviated as copper damage) occurs.

For this reason, conventionally, when using polypropylene or a polypropylene resin as an insulator, a copper damage inhibitor is added to these resins (Patent Document 1), or the copper conductor side is plated (tin plating). Etc. are done.
JP2003-020372A

  However, when a copper damage inhibitor is added to the insulator resin, if the addition amount is too small, an effective copper damage prevention effect cannot be obtained, so that it is naturally necessary to add a certain amount. Since this required addition amount is not necessarily a small amount, there is a problem that the characteristics of the normal insulator, for example, the dielectric loss tangent (tan δ) increases.

  When the tan δ of the insulator is increased, there is a problem that transmission loss increases when used in a high frequency region, for example, a GHz region, in a coaxial cable or the like.

  On the other hand, when the copper conductor is plated (tin-plated), the resistance of the conductor surface increases, so that there is a problem that the transmission loss of the cable also increases.

  Therefore, the present inventors use polypropylene or polypropylene-based resin as an insulator, while a copper damage prevention layer on a portion that comes into contact with these insulators, that is, a polyethylene layer, a cross-linked polyethylene layer, which is a resin resistant to copper damage, The idea was to provide a polyethylene-based resin layer or a foamed layer thereof, and when it was carried out, it was found that a good copper damage prevention effect was obtained.

  The present invention has been made based on such an idea, and basically a coaxial cable in which an insulator and a copper conductor are separated by a copper damage prevention layer so that a good copper damage prevention effect can be obtained. And an insulated cable.

  In the first aspect of the present invention, in the coaxial cable using polypropylene, a polymer thereof, a polypropylene-containing resin composition, or a foam thereof as an insulator, a copper damage prevention layer is provided inside the insulator. The coaxial cable is characterized by that.

  The present invention according to claim 2 is a coaxial cable using polypropylene, a polymer thereof, a polypropylene-containing resin composition, or a foam thereof as an insulator, and a copper damage prevention layer is provided outside the insulator. The coaxial cable is characterized by that.

  The present invention according to claim 3 is a coaxial cable using polypropylene, a polymer thereof, a polypropylene-containing resin composition, or a foam thereof as an insulator, and a copper damage prevention layer is provided on the inside and outside of the insulator. The coaxial cable is characterized by being provided.

  A fourth aspect of the present invention is the coaxial cable according to the first, second, or third aspect, wherein the copper damage prevention layer is a polyethylene layer, a crosslinked polyethylene layer, or a foamed layer thereof.

  The present invention according to claim 5 is the insulation cable using polypropylene, its polymer, polypropylene-containing resin composition, or these foams as an insulator, and a copper damage prevention layer is provided on the side in contact with the insulator. An insulated cable is provided.

  A sixth aspect of the present invention is the insulated cable according to the fifth aspect, wherein the copper damage prevention layer is a polyethylene layer, a crosslinked polyethylene layer, or a foamed layer thereof.

  In the coaxial cable or the insulated cable according to the present invention, even if polypropylene or polypropylene-based resin is used as an insulator, a copper damage prevention layer is provided on a portion that comes into contact with the insulator and the copper conductor. The insulator and the copper conductor are separated by the layer, and a good copper damage prevention effect is obtained.

FIG. 1 shows an embodiment of a coaxial cable according to the present invention.
In this coaxial cable 10, 11 is a central inner conductor made of a copper stranded wire conductor, etc., and 12 is a coating layer of polypropylene or a polypropylene resin (polymer thereof, polypropylene-containing resin composition, or foam thereof). An insulator, 13 is an outer conductor made of a copper stranded wire braid, and 14 is a sheath made of PVC or the like as the outermost layer. Reference numeral 15 denotes a copper damage prevention layer interposed between the inner conductor 11 and the insulator 12, and reference numeral 16 denotes a copper damage prevention layer interposed between the insulator 12 and the outer conductor 13.

  These copper damage prevention layers 15 and 16 are not particularly limited as long as they do not react with copper on the conductor side. For example, a polyethylene layer, a cross-linked polyethylene layer, or a foamed layer thereof centered on polyethylene that is less likely to react with copper than polypropylene can be used. As the polyethylene, any of low density, high density, linear low density, and the like can be used. Examples of other resin materials include polyamide-based resins, PTFE, FEP, PFA, and polyester.

  The copper damage prevention layers 15 and 16 made of such materials may be extrusion coating layers, or tapes made of these materials may be provided with gaps (overlapping portions) and added vertically or spirally wound. What is necessary is just to form by setting it as the tape coating layer which was made.

  Since these copper damage prevention layers 15 and 16 are interposed between the inner conductor 11 and the insulator 12, and between the insulator 12 and the outer conductor 13, the copper of each conductor portion is a polypropylene made of an insulator material. In addition, copper damage is fundamentally prevented because there is no direct contact with polypropylene resin. Depending on the use of the cable, either one of the copper damage prevention layers 15 and 16 can be used. Of course, in this case, the copper damage prevention performance is somewhat lowered.

FIG. 2 shows an embodiment of the insulated cable according to the present invention.
In this insulated cable 20, 21 is a central conductor made of a copper twisted wire conductor, etc. 22 is an insulation made of a coating layer of polypropylene or a polypropylene resin (polymer thereof, polypropylene-containing resin composition, or foam thereof). , 24 is a sheath made of PVC or the like as the outermost layer, and 27 is a copper damage prevention layer interposed between the central conductor 21 and the insulator 22.

  Even in the normal insulated cable 20, by providing the copper damage prevention layer 27, the copper in the conductor portion is not directly brought into contact with the insulating material polypropylene or polypropylene resin, so that the copper damage is fundamentally prevented. Is done. The configuration of the copper damage prevention layer 27, the material used, and the like may be the same as those of the coaxial cable 10. Also, the cable structure is not limited to the case of FIG. 2, and basically any other structure can be used as long as the copper damage prevention layer 27 is provided at the portion where the insulator and the copper conductor come into contact. Shall be.

<Examples and comparative examples>
As a coaxial cable (Example) according to the present invention, a coaxial cable having the same structure as that of FIG. 1 was manufactured under the following conditions. The outer diameter of this coaxial cable is about 3.0 mm, the inner conductor is a copper twisted wire conductor in which seven outer diameter 0.18 mm copper wires are twisted, the inner copper damage prevention layer is a 0.05 mm thick polyethylene layer, Insulator is 0.43mm thick polypropylene layer, outer copper damage prevention layer is 0.05mm thick polyethylene layer, outer conductor is copper wire braided with 0.1mm outer diameter copper wire, sheath is 0mm thick A 4 mm PVC layer was obtained. In addition, although about 1000 ppm of antioxidant is added to the polypropylene layer of the insulator and the polyethylene layer of the copper damage prevention layer, the copper damage prevention agent is not added.

  As a coaxial cable for comparison (comparative example), a coaxial cable having the same structure as that of FIG. 3 was manufactured under the following conditions. The outer diameter of this coaxial cable is about 3.0 mm, the inner conductor is a copper twisted wire conductor in which seven outer diameter 0.18 mm tin-plated copper wires are twisted, the insulator is a polypropylene layer having a thickness of 0.53 mm, the outer conductor Was a braided copper wire braided with 0.1 mm outer diameter tin-plated copper wire, and the sheath was a PVC layer with a thickness of 0.4 mm. In addition, although about 1000 ppm of antioxidant is added to the polypropylene layer of the insulator, copper damage inhibitor is not added.

  In the coaxial cables of these examples and the comparative example, when a transmission test was performed at a frequency of 3.0 GHz, the attenuation of the coaxial cable of the example was 16.2 dB / 10 m, and the attenuation of the coaxial cable of the comparative example. Was 16.7 dB / 10 m. That is, when a difference of 0.5 dB was recognized at 10 m, it was found that the coaxial cable according to the present invention has a small attenuation and a good result can be obtained.

Moreover, when both the coaxial cables of the above example and the comparative example were left in an atmosphere of about 200 ° C. and the oxidation induction period (time until the start of oxidation deterioration) inside the insulator in contact with the inner conductor was measured, In both the coaxial cables of the examples, the onset of oxidative degradation was recognized in about 22 minutes, but in both the coaxial cables of the comparative examples, the onset of oxidative degradation was recognized in about 5 minutes.
From this, in the case of the coaxial cable of the example, it can be seen that the oxidation induction period is approximately four times longer than both the coaxial cables of the comparative example. When the oxidative deterioration in the insulator starts, the attenuation of the cable transmission characteristics increases rapidly, so the coaxial cable of the example maintains good cable transmission characteristics over a long period of time even when used in a high temperature environment. Will be.

It is a longitudinal section used as one embodiment of the coaxial cable concerning the present invention. It is a longitudinal section used as one embodiment of an insulated cable concerning the present invention. It is a longitudinal cross-sectional view which becomes an example of the conventional coaxial cable.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Coaxial optical cable, 11 ... Inner conductor, 12 ... Insulator, 13 ... Outer conductor, 14 ... Sheath, 15, 16 ... Copper damage prevention layer, 20 ... Insulation Optical cable, 21 ... conductor, 22 ... insulator, 24 ... sheath, 27 ... copper damage prevention layer

Claims (6)

  A coaxial cable using polypropylene, a polymer thereof, a polypropylene-containing resin composition, or a foamed product thereof as an insulator, wherein a copper damage prevention layer is provided inside the insulator.   A coaxial cable using a polypropylene, a polymer thereof, a polypropylene-containing resin composition, or a foamed material thereof as an insulator, wherein a copper damage prevention layer is provided outside the insulator.   A coaxial cable using polypropylene as an insulator, a polymer thereof, a polypropylene-containing resin composition, or a foamed product thereof, wherein a copper damage prevention layer is provided on the inside and outside of the insulator. .   The coaxial cable according to claim 1, wherein the copper damage prevention layer is a polyethylene layer, a crosslinked polyethylene layer, or a foamed layer thereof.   Insulated cable using polypropylene, its polymer, a polypropylene-containing resin composition, or a foamed product thereof as an insulator, wherein a copper damage prevention layer is provided on the side in contact with the insulator . The insulated cable according to claim 5, wherein the copper damage prevention layer is a polyethylene layer, a crosslinked polyethylene layer, or a foamed layer thereof.

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