JPS59194311A - Electric cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in rubber and plastic insulated plastic earth cables, and in particular to cables that prevent the insulation layer of the cable from deteriorating due to water absorption, are resistant to chemicals, and are flame retardant. It is.

In rubber and plastic insulated electrical cables, cross-linking is performed to improve the thermal properties of the insulator. For example, in the case of plastics with excellent electrical properties such as polyethylene, cross-linking improves the thermal properties, making them suitable for use as high-voltage cables. It is developing. However, as the voltage increases, the existence of water-tree and ze-tree phenomena is recognized.

The influence of water due to steam crosslinking during the manufacturing stage has been debated, and a new dry crosslinking method has been used to prevent moisture from entering the insulation during the manufacturing stage of cables. Even if moisture intrusion is prevented at the initial stage, moisture may enter the cable sheath due to the surrounding environment after the cable is installed.
It is quite conceivable that the water will eventually penetrate into the insulating layer and cause dielectric breakdown due to the water tree phenomenon during operation of the cable.

At the same time, if the cable is installed in an atmosphere containing chemical solutions or gases, the insulation may deteriorate due to chemicals, etc. Furthermore, ordinary insulation layers such as polyethylene are flammable, so special consideration must be given to flame retardancy. One solution to this problem is to wrap a metal-silastic laminate tape around the cable core, or to use corrugated steel sheathing or lead-sheathed cables. The latter is heavy, expensive, and difficult to handle, while the former requires careful consideration of metal and plastic laminate materials.

For example, in the case of aluminum, plastic laminate,
Aluminum is easily attacked by chemicals and is not practical. Also, the plastic in the laminate cannot be made into a practical product unless it is carefully examined in relation to the sheath.

The present invention has been made in view of the above circumstances, and will be described below with reference to the drawings.

The figure shows an example of the electric cable of the present invention, in which an inner semiconducting layer 2, an insulating layer 3 such as cross-linked polyethylene, an outer semiconducting layer 4, and a wire shield 5 are applied around a conductor 1 to form a cable core 6f.
r, constitutes. Next, a laminate tape 11 of lead or lead alloy and plastic is attached vertically, and a polyvinyl chloride sheath 12 is applied to the outside of the tape 11 to form an electric cable.

The detailed structure of the lead or lead alloy and plastic laminate tape 11 is shown in FIG. It is shi.

That is, a conductive polyvinyl chloride layer 8 is provided on one side of the lead or lead alloy tape 70, and a polyester such as polyethylene terephthalate or a hard to semi-hard polyvinyl chloride layer 9 and a thermoplastic polyester layer 10 are sequentially formed on the opposite side. Install lead or lead alloy and plastic laminate tape 1
1. Such a laminate tape 11 is used to apply the conductive polyvinyl chloride layer 8 on the wire shield 5 of the cable core 6 so as to be in close contact with it when constructing the cable shown in FIG.

In the above cable, the sheath is made of polyvinyl chloride,
The plastic used in the laminate is also polyvinyl chloride or polyester, so it is relatively flame retardant, and the metal used in the laminate is lead or lead alloys, which ensures that the cable insulation is completely water resistant. This guarantees chemical resistance. However, since lead or lead alloy sheets are too soft, they are coated with a layer of polyester such as polyethylene terephthalate or hard or semi-hard polyvinyl chloride, which allows for efficient vertical mounting or This allows for wrapping. In addition, the thermoplastic polyester layer 10 adheres well to the conductive polyvinyl chloride layer 8 in the laminate tape 11, the polyester such as polyethylene terephthalate or hard to semi-hard vinyl chloride layer 9, and the polyvinyl chloride sheath 12 of the outermost layer of the cable. The structure is such that there are no gaps between the layers.

The structure of this thermoplastic polyester is an amorphous, high molecular weight saturated polyester formed by the condensation polymerization of a dibasic acid and a dihydric alcohol.The structure of this thermoplastic polyester is an amorphous high molecular weight saturated polyester formed by the condensation polymerization of a dibasic acid and a dihydric alcohol. It is effective.

The conductive polyvinyl chloride layer 8 on one side of the laminate is made of a composition in which a conductive casen blank is blended into polyvinyl chloride, and the outer semiconductive layer 4 on the surface of the cable core is
It acts integrally with the wire shield 5.

As described above, the present invention uses a lead or lead alloy tape, and a cable core is coated with a laminate tape made by laminating a specific plastic material, and is then covered with a polyvinyl chloride sheath coated by extrusion. It is an electric cable that exhibits the specified ice, chemical, and flame resistance effects.

Although the above description has been made of a cable with a wire shield, the cable can be similarly implemented in the case of a copper tape-wrapped seal V instead of the wire shield.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of the electric cable of the present invention;
FIG. 2 is a cross-sectional view showing the structure of the laminate tape used in the cable. 1... Conductor 2... Circular semiconductive layer 3-... Insulator 4... External semiconductive layer 5... Wire shield 6...
- Cable core 7 - Conductive polyvinyl chloride layer 8 - Lead or lead alloy tape 9 - Polyester such as polyethylene terephthalate or rigid or semi-rigid polyvinyl chloride 1G - Thermoplastic polyester 11 - Laminated tape 12...Po'Jm vinyl sheath Agent Patent attorney Mori Takeuchi Seki 1 Seki 2 Figure 1

Claims (1)

[Claims] A conductive polyvinyl chloride layer is provided on one side of a tape made of lead or lead alloy on the outside of the cable core having a rubber or plastic insulation layer, and a polyester layer or a hard to semi-hard polyvinyl chloride layer is provided on the other side. A laminate tape comprising a thermoplastic polyester layer and a thermoplastic polyester layer is placed vertically or horizontally with the conductive polyvinyl chloride layer inside, and a polyvinyl chloride layer is provided on top of the laminated tape. electric cable.