JPS62176006A - Water-penetration-proof cable and manufacture of the same - 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] [Industrial Application Field] The present invention relates to a water running prevention type cable and a manufacturing method thereof;
The object of the present invention is to significantly improve the water running resistance of this type of cable, thereby increasing its durability, and to provide a manufacturing method for easily obtaining the same.

[Conventional technology]

Traditionally, outdoor high-voltage cables, such as CV cables,
Due to the occurrence of a 2-tooth (or sheath) trauma accident, other water intrusion or deterioration due to a/I2I, or water seeping into the cable from the end of the wire, phenomena such as water treeing may occur, resulting in a decline in cable performance and damage to insulation. The problem is that it causes destruction.

In order to solve these problems, water running prevention cables have recently been used for outdoor high-voltage power lines, etc. Especially recently, there has been an increasing demand for higher-voltage power transmission and maintenance-free cables. It is expected that the performance will be improved more and more. Needless to say, in response to such demands, various studies have been made not only on the materials used to construct the cable, but also on the structure of the cable.

For example, with regard to cable constituent materials, various improvements have been made to the waterproof material of the jacket and the waterproof material of the insulating layer.On the other hand, regarding the structure of the cable, the inner surface of the fat jacket is filled with a specific watertight resin compound, TBL
Providing thermoplastic resin foam tape with base fabric, +C1
Measures have been taken, such as providing a conductive or semiconductive watertight tape containing foamed thermoplastic resin particles together with the base fabric. However, in the former case and the latter case, there is a limit to the extent to which drastic improvements can be made due to the usage pattern of the electric wire, and many drawbacks have been pointed out in the latter case (bl to (cl) as well. In other words, the thickness of the tape foam layer limits the length and makes the taping operation difficult, and the thickness of the conductive layer or semiconductive layer in the jacket and insulating layer tends to become uneven, so it is difficult to prevent water running. The disadvantage is that it is difficult to achieve sufficient results.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is to solve the above-mentioned drawbacks of conventional anti-water running cables and to develop a method for easily producing cables free of such drawbacks. An object of the present invention is to develop a water-travel-preventing cable that is even more excellent in water-travel prevention properties and durability in a water-travel prevention type cable composed of a cable, a watertight layer, and a jacket, and a method for manufacturing the same.

[Means for solving problems]

The above problem is that in cables that have a sandwich structure layer of semiconductive tape/wire strand/semiconductive tape on the inner surface of the jacket, the main components of the semiconductive tape are expanded foam of thermally expandable microcapsules and super absorbent water. This is achieved by using a tape containing heat-expandable microcapsules and a super absorbent resin as a semiconductive tape, and at the time of forming the jacket or before forming the jacket. This is achieved by heating the thermally expandable microcapsules to expand and foam them.

[Configuration and operation of the present invention]

The present invention will be explained with reference to the drawings. FIG. 1 shows a cross-sectional view of the anti-water running cable of the present invention. First, the insulated cable (
A> consists of a conductor (1), an extruded inner half layer (2), an insulator (3) and an extruded outer layer (4), and this insulated coated cable (
A semiconductive tape (5), wire strands (6), and semiconductive tape (7) are sequentially provided on the outside of A) to form a watertight layer (B), and then the watertight layer (B) is heated and foamed. After that, cover with a jacket (8).

Here, the semiconductive tape forming the watertight layer (B) must contain as main components an expanded foam of thermally expandable microcapsules and a super absorbent resin. There is. And as each tape,
A normal tape that does not contain either of these at all, a tape that contains at least one of these as a main component and that contains both of these as a whole, or a tape that contains both of these are used. Ru. These expanding foams and superabsorbent resins can be contained in two types: one is that they are contained inside the tape, and the other is that a coating layer containing these components is formed on the surface of the tape.

Typical examples of the forms in which the expanded foam and superabsorbent resin are contained in these semiconductive tapes are shown in Table 1 below. However, for convenience, the expanded foam is shown as (i) and the super absorbent resin is shown as (11).

These semiconductive tapes include thermally expandable microcapsules and/or semiconductive tapes prepared from a compound itself containing a superabsorbent resin, or ordinary semiconductive tapes with thermally expandable microcapsules and/or A typical example is a tape coated with a composition containing a super absorbent resin. It goes without saying that in the present invention, a normal tape containing neither of these at all may be used as one of the tapes. However, in the case of coating, it is preferable to form the coated surface on the wire strand side.

A thermally expandable microcapsule is one that contains a volatile liquid (butane, hexane, fluorotrichloromethane, etc.) in the center.
, has a thermoplastic resin (acrylonitrile, its copolymer, etc.) layer that softens at a temperature higher than the vaporization temperature of the volatile liquid on the outside, and a gelatin-based coating layer as the outermost shell layer, and generally has a thickness of about 1 to 50 microns. Served. In addition, super absorbent resins include polyacrylate-based, polyvinyl alcohol/cyclic acid anhydride graft copolymer, starch/polyacrylic acid graft copolymer, vinyl acetate/acrylic ester copolymer, and starch/polyacrylic acid ester copolymer. These include acrylonitrile graft copolymer systems, carboxymethyl cellulose systems, etc.

These thermally expandable microcapsules, superabsorbent resins, or thermally expandable microcapsules and superabsorbent resins are combined into a semiconductive composition consisting of a base polymer such as ethylene rubber, butyl rubber, or EVA, and conductive particles (carbon black, etc.). The semiconductive tape (5) or (7) is obtained by appropriately blending it into a product and processing it into a tape, or by coating it on a tape made of ordinary base fabric such as plastic. Preferable base fabrics of this type are woven fabrics or non-woven fabrics made of various fibers.

To explain the anti-water running cable of the present invention in more detail with reference to FIGS. 2 to 5, FIG. This shows the state before heating and foaming sandwiched between a tape (5) made of a resin-containing compound and having semi-conductivity and a tape (7) made of a compound containing heat-expandable microcapsules and having semi-conductivity. As shown in FIG. 3, the semiconductive tapes (5) and (7) foam in the direction of the wire strand (6) and fill the voids. Figure 4 is an example in which the semiconductive tape on the insulated cable (A) side in Figure 2 contains only a super absorbent resin, and the semiconductive tape on the (8) side is Tape (7)
Only the foam was formed. FIG. 5 shows that, in place of the thermally expandable microcapsules and the compound tape containing the thermally expandable microcapsules and superabsorbent resin in FIG. An example is shown in which a tape coated with a composition containing capsules (5-2) and a composition containing thermally expandable microcapsules and a superabsorbent resin (7-2) is used, and the composition layer is coated with a wire strand. (6) It is foamed in the direction. In this way, the remaining voids in the wire strands (6) sandwiched with semiconductive tapes are completely or almost eliminated and a foam layer with closed cells is formed, so that almost no water running occurs. This can be effectively prevented without any problems.

Examples of the wire strand used in the present invention include copper and conductors, and examples of the jacket include materials such as vinyl chloride and ethylene, which have good barrier properties against water, steam, chemicals, and the like. Further, the mutual adhesion of the semiconductive tape can be further improved by making the surface uneven or giving it some degree of plasticity in order to increase the degree of surface contact with the wire strands.

According to the present invention, by using a tape using thermally expandable microcapsules or a composition containing thermally expandable microcapsules and a superabsorbent resin, the length can be adjusted at will, and the thickness does not need to be very large. Therefore, uneven thickness can be avoided in forming a watertight layer, and due to the foamed adhesiveness of such a tape, a watertight layer with good mutual adhesion between the semiconductive tape and the wire strands can be easily obtained without using an equivalent adhesive.

〔Effect of the invention〕

As explained above, the water running prevention type cable of the present invention is
Manufacturing advantages such as easy taping, no need for troublesome watertight layer formation, no need for adhesives, tape formation operations can be performed as usual, heating operations can be saved depending on the situation, etc., and watertightness. In addition to the advantage that it is extremely useful and optimal for the durability of the cable in that it prevents uneven thickness of the layer and water running, it also allows the formation of a stronger layer without significantly impairing the conductivity of the watertight layer. be.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the water running prevention type cable of the present invention, Figure 2-
Figure 5 shows a partial sectional view of the process of forming a watertight layer of a water-travel prevention type cable, and each symbol indicates the following. (A) Insulated cable...(1): Conductor, (2)
: Extruded inner half layer, (3) : Insulator, (4): Extruded outer half layer (B) Watertight layer... (5) - Semi-conductive tape, (6)
: Wire strand, (7) : Semiconductive tape (8) : Jacket

Claims (5)

[Claims] (1) In a cable that has a sandwich structure of semiconductive tape/wire strand/semiconductive tape on the inner surface of the jacket, this integrated tape is used as a tape that combines the above two semiconductor tapes to expand thermally expandable microcapsules. A water running prevention type cable characterized by being mainly composed of a foam and a super absorbent resin. (2) Claim 1, wherein the other tape of the semiconductive tape mainly composed of an expanded foam of thermally expandable microcapsules is composed mainly of a superabsorbent resin. Water running prevention type cable. (3) The other tape of the semiconductive tape mainly composed of an expanding foam of a thermally expandable microcapsule and a super absorbent resin is a thermally expandable microcapsule or (and)
The water running prevention type cable according to claim 1, which is made of a super absorbent resin as a main component. (4) Only one side of the semiconductive tape mainly consists of an expanding foam of thermally expandable microcapsules and a super absorbent resin,
The anti-water running cable according to claim 1, wherein the other tape is a tape containing neither an expanded foam of thermally expandable microcapsules nor a superabsorbent resin. (5) In a cable that has a sandwich structure layer of semiconductive tape/wire strand/semiconductive tape on the inner surface of the jacket, one of the semiconductive tapes contains thermally expandable microcapsules and superabsorbent resin as the main components. 1. A method for producing a water running prevention type cable, which comprises using a tape comprising the above-mentioned thermally expandable microcapsules, and heating the thermally expandable microcapsules at the time of or before forming the jacket to expand and foam the thermally expandable microcapsules.