JPS59211913A - Water permeation preventive 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 a water permeation prevention cable, and more particularly to a corrugated type laminate sheathed cable treated to prevent water permeation.

The protective covering sheath of cables, eg power capes) v2 and communication cables, not only provides mechanical protection for all conductors within the cable core, but also serves to ensure the overall waterproofing of the core.

In the old days, lead was used for cable sheaths, but
Currently, aluminum is mainly used in place of lead because of its low mechanical strength and high weight. However, although aluminum has excellent mechanical strength, it is a hard material and may reduce the flexibility of the cable.

Therefore, in order to increase the malleability of metal cables, it has been proposed to apply a corrugated metal thin tape, such as iron, nutless, copper, or aluminum tape, vertically around the cable core. The abutting edges of the vertically attached laminated metal tapes were joined together by electric resistance stitching, etc., but this method was expensive, so recently, the seams of the vertically attached corrugated tape 1 were simply overlapped, Cables with poly:rfV,/t-coated on the outside, such as Alves sheathed cables and Stalves sheathed cables, have been developed. Furthermore, a laminated sheath cable or a glover sheath cable has been developed that uses an aluminum tape with a thin plastic film layer that is easily adhered to the polyethylene sheath formed in advance on one or both sides of the tube.

However, due to the laminated structure of the overlapping portions of the laminated metal tapes, it is difficult to overlap them without any gaps, and water and moisture may enter the core through the gaps.

The present inventors conducted research to economically improve the water permeation prevention properties of the laminated tape overlapping part of a corrugated type laminated sheath cable, and found that by supplying a compound with a high flash point to the overlapping part. The present inventors have discovered that the water permeation prevention properties are significantly improved and have completed the present invention.

The gist of the present invention resides in a water permeation prevention cable characterized in that, in a corrugated type laminate sheathed cable, a compound having a flash point of 250° C. or higher is supplied to the overlapping portion of corrugated type laminate tapes longitudinally attached around the core.

In the present invention, the laminated sea cable is of a conventional and usual structure1, and also includes a sherry-filled cable filled with a waterproofing compound to prevent water from running inside the core.

■The compound that is applied and supplied to the joining part generally has a flash point of 250°C or higher, preferably 300°C or higher.
It is a highly volatile compound with temperatures above 350'C. If the flash point of the compound is low, that is, if the compound has low volatility, it is not preferable because gas will be generated by the heat during coating the polyethylene sheath and cause blistering of the polyethylene sheath.

The compound desirably has excellent adhesion to the single layer of polymer coated on the aluminum tape, and from the viewpoint of water permeation prevention, it is preferable that the compound does not crack even when solidified.

Examples of compounds include compounds consisting of atactic polypropylene, mineral oil and rosin, compounds consisting of atactic polypropylene, polybutene 3 and petroleum wax, and combinations thereof.

The cable of the present invention can be manufactured in the same manner as conventional laminated sheath cables, except that the compound is applied to the surface of the overlapping portion of the corrugated type laminate tape.

FIG. 1 shows a cross section of an example of the structure of the cable of the present invention.

In this structure, a corrugated laminated metal tape 2 is longitudinally attached around a sherry-filled cable core 1, and a compound 3 for preventing water permeation is supplied to the overlapped portion. A polyethylene sheath is placed around the metal tape 2,
4 is extrusion coated.

Next, examples will be shown to specifically explain the present invention.

Examples 1 to 32 and Comparative Examples 1 to 2 0.5 to 100 pairs of corrugated laminated aluminum sheathed cables with sherry-filled expanded polyethylene insulation,
The following compound was supplied to the overlapping part of the aluminum sheath (not supplied in Comparative Example 1), and the cable water permeation prevention property was determined by B,
P, 0.5 pec, M l Evaluation was made in accordance with 42C.

Compound composition (parts by weight) A near tactical polypropylene 60 mineral oil
350 gin
5 B Near Tactical Polypropylene 5゜Polybutene 40 Petroleum Warehouse
10C near tactical polypropylene 5
5 Polybutene 40 Rosin
5D: oil
40 petroleum wax 45
polybutene 10 rosin
5 The results are shown in the table below.

table Note 1) 2 to 3 pieces 710m

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of the cable of the present invention. 1... Cable core, 2... Corrugated laminate metal tape, 3... Compound, 4...
...Polyethylene sheath. Patent applicant: Dainichi Nippon Electric Cable Co., Ltd. Representative: Patent attorney: Aohaku Ao (2 others) Figure 1, 59-

Claims (1)

[Claims] 1. Corrugated type laminate sheath cable 2.
A water-permeable prevention cable characterized in that a compound with a flash point of 250°C or more is supplied to the overlapping part of corrugate-type laminated tape attached vertically around the core.