JPS5981804A - Watertight 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 watertight cable in which a watertight mixture is filled between the strands of stranded conductor wires.

This is because there is a risk of oxidation and corrosion of the conductor wires if moisture infiltrates between the conductor wires, not only for submarine cables and other cables that are installed under constant water immersion, but also for outdoor high-voltage distribution lines and outdoor low-voltage distribution lines. However, there are some problems that cannot be solved simply by improving the sheath portion, and for this reason, it has been considered to fill the gaps between the conductor strands with a water-like mixture. Most of these watertight mixtures fill the conductor gap with the mixture in a heated fluid state, but it is difficult to completely fill the entire length of a long and slender cable, and height differences occur during the installation stage. Therefore, a flow phenomenon may occur in the watertight mixture, and voids may locally regenerate, so the emergence of a more perfect technology has been long awaited.

As a result of various studies, the inventors of the present invention have found that, without simply using a watertight mixture with high viscosity and fluidity mainly consisting of polyisobutylene or fluid rubber as in the past, the present inventors have developed a completely watertight structure that can be used immediately in the event of water infiltration. He invented a water prayer cable that could be used at the water's edge.

That is, as shown in the drawing, the present invention provides a composition 2 mainly composed of rubber or plastic and a super absorbent resin between the twisted wires of a conductor 1.
Although not shown in the drawings, such cables are usually twisted together with a necessary number of intervening elements, and are made of a plastic sheath and a metal cable. A sheath or a combination of these sheaths is provided to constitute a cable.

In the above, the rubber or plastic constituting the watertight composition includes butadiene rubber and urethane rubber.

Rubbers such as ethylene propylene terpolymer, styrene-ptadiene rubber, polyethylene/ethylene-vinyl copolymer, polyethylene ethyl acrylate.

Can be used for vinyl chloride/vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, etc.

Examples of super absorbent resins include acrylic acid (salt) grafted starch, vinyl alcohol acrylic acid (ba) block copolymer, and crosslinked polyacrylic acid (salt).

All kinds of citrus materials such as modified PVA are applicable.

The blending ratio of rubber or plastic and superabsorbent resin is generally selected as appropriate between 1 and 200 parts by weight per 100 parts by weight of rubber or plastic, although it depends on the specific type of accessory.

In addition to the rubber or plastic that serves as the paste and the superabsorbent resin, the above composition also contains appropriate amounts of crosslinking agents, inorganic fillers, pigments (including Chikarazen Black), plasticizers, anti-aging agents, etc., as necessary. Can be used mixed. A rubber or plastic insulator is extruded and coated on the watertight conductor, twisted together with an intervening material for several seconds, and then a sheath material such as polyvinyl chloride, chloroprene, or corrugated metal is coated on the outside. The cable is completed.

If moisture gets into any part of such a cable, nk 7! ils, the water is immediately captured by the water-absorbing resin and the gaps between the conductors are completely saturated with water, so water does not flow in the longitudinal direction and corrosion of the conductors does not occur at all.

As an example of the present invention, 20 parts by weight of a starch-based water-absorbing resin was added to 100M of ethylene-vinyl copolymer on 7 conductors/2.6m, and 100. iOkibe.

When we prototyped cables sequentially coated with three types of polyethylene insulated vinyl chloride sheaths filled with 200 parts by weight, and when water was injected from the ends of the cables, the conductor filling mixture immediately solidified and swelled at the core of each cable. It was completely watertight, and no water leaked out on the other side.

It should be noted that the cable according to the present invention does not suffer from any loss in flexibility as with conventional cables.

[Brief explanation of the drawing]

The figure is a cross-sectional view showing one embodiment of the present invention.

Claims (1)

[Claims] Rubber or plastic and super absorbent material (4
A watertight cable characterized by being filled with a composition mainly consisting of oil and having a rubber or plastic insulating layer provided on the outside.