JPH10302561A - Water running preventing stranded wire conductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide sufficient water running preventing function by applying polyether synthetic oil to a central conductor, attaching water absorbing, expanding powder thereon to form a stranded wire layer, applying the polyether synthetic oil to the stranded wire layer, then attaching water absorbing, expanding powder thereon. SOLUTION: A central conductor is supplied in the arrow direction with a central conductor supply device 15, and a polyether synthetic oil cover and a water absorbing, expanding powder attaching layer are formed on only the central conductor in a position 21. According to the number of necessary stranded wire layers, polyether synthetic oil coating and powder attaching are conducted in positions 22, 23, 24, 25 with stranded wire layer stranding machines 11-14, and a presser tape 16 is wound in the arrow direction so as to prevent the scattering of the water absorbing, expanding powder attached to the stranded wire conductor obtained. The stranded wire conductor is used in an electric wire or cable, and in the cable for example, the presser tape, an inner semi-conducting layer, an insulating layer, and an outer semi-conducting layer are arranged in order on a wire conductor, then a protecting sheath is covered thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a stranded wire conductor capable of preventing water running.

[0002]

2. Description of the Related Art Conventionally, electric wires and cables are formed by processing a central conductor (core wire) made of a metal wire into a multi-layered structure, and a pressing tape, an insulator and a protective sheath are provided thereon. . However, an unexpected accident during use causes some damage to the wires, cables or their connection parts, etc., from which moisture such as rain penetrates into the stranded layer or reaches the center conductor, and the center conductor and There is also a problem that water runs by capillary action, that is, water runs in the gap between the stranded layers. This water running causes problems such as corrosion of the conductor and deterioration of the electrical performance of the insulator covering the conductor.

[0003] Therefore, various methods have been proposed for filling the voids between the wires constituting the electric wire or the like with a water-absorbing and swellable powder. The water-absorbing and swellable powder absorbs water and swells to close the voids, thereby preventing water from penetrating further into the inner layer and preventing water running.

However, usually, the surface of the wire is polished, and the lower central conductor is rotated during the laying process, so that the water-absorbing and swellable powder can be efficiently removed from the wire. There was a problem that it could not be attached to the surface.

On the other hand, Japanese Utility Model Laid-Open Publication No. Sho 56-46110 proposes that a thin film of an adhesive die is provided on the surface of a metal wire before the water-swellable powder is attached.

However, since the adhesive die roll has a high viscosity, not only is it difficult to apply it to metal strands, but also the thickness of the layer formed by applying it becomes non-uniform, resulting in various types of electric wires and the like. There is a problem that the filling amount of the water-absorbing and swellable powder varies in the gaps between the strands, and the reliability of the function of preventing water running decreases.

The inventors of the present invention have found that the use of a specific oil can form a uniform film and can efficiently adhere (fill) the water-absorbing and swellable powder, thereby solving the above problems. The present invention has been completed.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a water transport preventing wire conductor having a water absorbing and swelling powder uniformly adhered and filled throughout, and having a sufficient water running preventing function.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a stranded conductor having a center conductor made of a metal strand and a stranded layer made of a plurality of metal strands, comprising a polyether synthetic oil on the center conductor. After applying the water-absorbing swellable powder to form a wire layer, and then applying a polyether synthetic oil on the wire layer and attaching the water-absorbing swellable powder, The present invention relates to a method for manufacturing a conductor.

In this case, the polyether synthetic oil is preferably polyoxyethylene polyoxypropylene monobutyl ether.

Further, the water-absorbing swellable powder is preferably made of sodium polyacrylate.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a stranded conductor having a center conductor composed of a metal strand and a stranded layer composed of a plurality of metal strands. After applying and adhering the water-absorbing swellable powder, a wire layer is formed, and then a polyether synthetic oil is applied on the wire layer to adhere the water-absorbing swellable powder, thereby preventing the water from swelling. A method for producing the same.

FIG. 1 is a schematic sectional view showing the concept of a strand conductor for preventing water running obtained in the present invention. In FIG. 1, 1
Denotes a metal strand, 2 denotes a polyether synthetic oil coating, and 3 denotes a water-absorbing and swellable powder adhered layer. According to the present invention, on the center conductor and the stranded wire, the thickness of the polyether synthetic oil coating 2 is made uniform, and the water-absorbing and swelling properties are obtained by adhering the water-absorbing and swelling powder evenly between the metal wires. The powder adhering layer 3 can be formed, and a stranded conductor having an excellent water running preventing function can be obtained.

The metal wire that can be used in the present invention may be any conductive material (conductor) that constitutes an electric wire and a cable. For example, copper, copper alloy, aluminum, aluminum alloy and the like can be mentioned.

Further, the metal surface is coated with another metal by electroplating, hot-dip plating, etc., a phosphate film is formed by a phosphate treatment, or a metal oxide is formed by anodic oxidation or thermal oxidation. What was done is given.

Of these, from the viewpoint of improving the electrical conductivity, it is preferable to use a copper or copper alloy as the center conductor and to use a copper or copper alloy as the stranded wire.

The diameter of the metal wire used in the present invention is not particularly limited as long as it is within the range of those conventionally used for electric wires and cables. What is necessary is just 5 mm.
In addition, when used for a stranded wire, it may be 1 to 5 mm.

Further, in the present invention, the polyether synthetic oil applied to the center conductor and the stranded wire layer forms a uniform film on the surface of the metal wire by application to cause corrosion and discoloration of the metal wire. In the following step, it also serves as an adhesive so that the water-absorbing swelling powder can be efficiently attached in the subsequent step, and does not impair the water-absorbing swelling property of the powder. It does not swell a semiconductive layer made of a vinyl acetate copolymer or the like. Examples of such polyether synthetic oils include polyoxyethylene polyoxypropylene monobutyl ether, polyoxyethylene polyoxypropylene diethyl ether, and the like. It is particularly preferable to use polyoxyethylene polyoxypropylene monobutyl ether because it does not adversely affect the constituent materials such as the semiconductive layer and the insulating layer provided thereon when the cable is manufactured. .

Further, the polyether synthetic oil forms a film having a uniform thickness on the surface of the metal strand, has a low viscosity, and specifically, is 400 centipoise or less from the viewpoint of easy application. It is more preferably 200 to 400 centipoise from the viewpoint that it does not drip after coating.

The thickness of the polyether synthetic oil film formed on the surface of the metal wire according to the present invention is not particularly limited, but is 50 to 500 μm from the viewpoint of uniformly adhering the water-swellable powder. It is more preferably 50 to 200 μm from the viewpoint that the water-absorbing swellable powder does not absorb moisture with the polyether synthetic oil.

In the present invention, as a method of applying the polyether synthetic oil to the center conductor and the stranded layer, for example, brushing, spraying, dipping, etc. can be mentioned, but a more uniform film can be formed as a whole. In view of this, it is preferable to perform spraying.

Next, in the present invention, the water-absorbing and swelling powder to be adhered after the polyether synthetic oil is applied onto the central conductor and the stranded layer has been conventionally used for electric wires and cables for preventing water running. Can be used. Those having a water absorption ratio of 10 to 500 times are preferable, and those having a water absorption ratio of 50 to 200 times are particularly preferable. Specific examples of these water-swellable powders include, for example, sodium polyacrylate, potassium polyacrylate,
Starch-polyacrylate-based graft copolymer, acrylic acid-vinyl alcohol copolymer, alkali hydrolyzate of acrylonitrile / vinyl chloride / ethylene monomer copolymer, acrylonitrile / vinylidene chloride / ethylene monomer Polyacrylic acid-based organic polymers, such as an alkali hydrolyzate of a copolymer with a monomer, a crosslinked formaldehyde of an acrylamide polymer, and a crosslinked formaldehyde of a polymer obtained by hydrolyzing an acrylonitrile polymer with an alkali; Epichlorohydrin crosslinked product of polyvinyl alcohol, phosphoric acid condensate of polyvinyl alcohol, copolymer of 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, and 2-methyl-5-vinylpyridine and N, N′-methylenebisacrylamide Copolymer, N, N'- Copolymer of methylaminoethyl methacrylate and N, N'-methylenebisacrylamide, copolymer of N-vinyl-2-pyrrolidone and ethylene glycol dimethacrylate, cross-linked polyoxyethylene by irradiation, acidity of starch Lower heat condensate, a dried product of a saponified copolymer of a vinyl ester and an ester unsaturated carboxylic acid or a derivative thereof, and the like,
It is preferable to use a polyacrylic acid-based organic polymer in that it does not adversely affect the metal strand, such as deterioration,
Further, it is particularly preferable to use sodium polyacrylate because it does not swell a semiconductive layer made of an ethylene-vinyl acetate copolymer or the like coated on the wire conductor when a cable is manufactured.

The average particle size of the water-swellable powder used in the present invention before water absorption is not particularly limited,
1 to 2 in terms of easy adhesion to polyether synthetic oil
The thickness is preferably from 00 to 100 μm, but is preferably from 20 to 100 μm from the viewpoint that it is difficult to be scattered in the work, and from the viewpoint that it is easy to uniformly adhere to the metal strand.
Particularly preferably, it is 80 μm.

The thickness of the adhesion layer formed on the wire conductor for preventing water running, which is obtained in the present invention, is a thickness having a water running preventing function, for example, 0.5 m to 2 mm.
Should be fine.

The stranded conductor for preventing water running in the present invention has one or more stranded layers except for the center conductor. The number of stranded layers depends on the cross-sectional area of the stranded conductor to be obtained, but is usually about 1 to 5 layers. Also, 1
The number of metal strands constituting the twisted layer of the layers is usually six for the first layer, twelve for the second layer, eighteen for the third layer, twenty-four for the fourth layer, and five for the fifth layer. The number of layers is 30.

FIG. 2 shows a manufacturing process diagram for obtaining a wire conductor for preventing water running according to the present invention. In FIG. 2, 11-1
Numeral 4 denotes a first to fourth strand twisting machine, 15 a feeder for supplying a metal strand as a central conductor, and 16 a pressing tape wound around the obtained strand conductor. Positions 21 to
Reference numerals 25 denote positions where polyether synthetic oil is applied and then water-absorbing swelling powder is attached.

In FIG. 2, the center conductor is supplied in the direction of the arrow by a center conductor feeder. First, at a position 21, a polyether synthetic oil film and a water-absorbing swellable powder adhesion layer are provided only on the center conductor. Then, a twisting machine is provided according to the required number of twisted layers, and the holding tape 16 is wound in the direction of the arrow so that the water-absorbing and swellable powder attached to the obtained twisted wire conductor is not easily scattered. The pressing tape is usually made of polypropylene, polyethylene, polyethylene terephthalate (Teflon) or the like.

The stranded wire conductor of the present invention can be used for electric wires and cables in a usual manner. For example, when used for a cable, the stranded wire conductor is pressed onto the stranded wire conductor obtained in the present invention in a usual manner. A tape, an inner semiconductive layer, an insulating layer, and an outer semiconductive layer are provided in this order, and further covered with a protective sheath.

The wire conductor for preventing water running obtained in the present invention is used in an environment where a large amount of water is present,
For example, it can be preferably used for underground cables.

[0030]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited only to these.

Example 1 In accordance with the manufacturing process diagram shown in FIG. 2, a copper conductor was used as a central conductor and a stranded wire as a stranded wire, and a polyether synthetic oil (polyoxyethylene polyoxypropylene monobutyl ether, viscosity: 360 Centipoise),
As the water-absorbing and swelling powder, one made of sodium polyacrylate (average particle size: 40 to 70 μm) is used, and after spraying oil onto the central conductor, the powder is adhered through a water-absorbing and swelling powder-filled box filled with the water-absorbing and swelling powder. Then, the stranding prevention wire strand conductor (66 kV, 250 mm ^{2) of the} present invention having five metal strand layers including the central conductor layer is formed by repeating the stranding, oil spraying and adhesion of the water-absorbing swellable powder. ,
61-strand compressed conductor). The outermost layer is wrapped with a pressing tape made of polypropylene, and ethylene-
An inner semiconductive layer made of a composition obtained by mixing carbon black with a vinyl acetate copolymer, an insulating layer made of crosslinked polyethylene, and an outer semiconductive layer made of a composition obtained by mixing carbon black with an ethylene-vinyl acetate copolymer A cable was obtained by sequentially covering the conductive layer and further covering a protective sheath made of polyvinyl chloride.

[Evaluation] A cable obtained by using a wire conductor for preventing water running was subjected to IEC (International)
Electrotechnical Commiss
ion) Water penetration test according to 840 (Water)
(Penetration Test). In the test, as shown in FIG. 3, the cable was cut off to a layer of the holding tape by a portion having a width A (50 mm) to expose the stranded wire conductor of the present invention. Evaluate how far the water will run in the length direction.

FIG. 3 is a schematic sectional view of the apparatus used for the water intrusion test. 31 is the cable obtained in Example 1, 32
Is a cut-out portion of the cable 31, and 33 is a pipe made of vinyl chloride, which is filled with water. Both ends are hardened with an epoxy-based adhesive 34 and a waterproof tape (not shown) so that water does not leak. 35 is a water tank. In FIG. 3, A is 50 mm, B is 1000 mm, and C is 10 mm.
That is all.

In order to simulate a damaged cable buried underground, the cable was heated, the conductor temperature of the cable was maintained at 90 ° C. for 8 hours, and then 10 heat cycles were performed in which heat was released for 16 hours.

Next, a protective sheath, a semiconductive layer, an insulating layer,
After removing the semiconductive layer and the holding tape, the wire layer was disassembled one layer at a time from the outside, and the extent of water running from the end of the center cutout was visually inspected together with the degree of flooding. . Starting from the end of the cut-off portion, the length (water running length) of a portion where water penetrated and the water-absorbing swellable powder had a mark of water infiltration was measured. Table 1 shows the results.

[0036]

[Table 1]

[0037]

According to the present invention, it is possible to obtain a wire conductor having a sufficient water running prevention function.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing the concept of a strand conductor for preventing water running obtained in the present invention.

FIG. 2 is a schematic view for explaining a method for manufacturing a wire conductor for preventing water running according to the present invention.

FIG. 3 is a schematic cross-sectional view of an apparatus used in a water penetration prevention test on a water conductor for preventing water running according to the invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 metal strand 2 polyether synthetic oil coating 3 water-absorbing and swellable powder adhesion layer 11 first twisted-layer twisting machine 12 second twisted-layer twisting machine 13 third twisted-layer twisting machine 14 fourth twisted-layer Twisting machine 15 Center conductor feeder 16 Holding tape 21, 22, 23, 24, 25 Polyether synthetic oil applied and water-absorbing swellable powder attachment position 31 Cable 32 Holding tape cut-off portion 33 PVC pipe 34 Epoxy adhesive 35 Aquarium

Claims (3)

[Claims] 1. A method for manufacturing a stranded conductor having a center conductor made of a metal strand and a stranded layer made of a plurality of metal strands, wherein a polyether synthetic oil is applied on the center conductor to absorb water and swell. A method for producing a line conductor by preventing water running, which comprises forming a wire layer after adhering, then applying a polyether synthetic oil on the wire layer and adhering a water-swellable powder. 2. The method according to claim 1, wherein the polyether synthetic oil is polyoxyethylene polyoxypropylene monobutyl ether. 3. The method according to claim 1, wherein the water-swellable powder comprises sodium polyacrylate.