JPS62272409A - Watertight cable and manufacture thereof - 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 3. Detailed Description of the Invention The present invention relates to a watertight cable with excellent water running prevention properties and a method for manufacturing the same.

``U'' and ``'' should be used. When making a cable waterproof, the gaps between the many cable cores in the sheath are generally filled with a waterproofing compound, but this type of cable is not installed underground. In the case of direct burial, it is required to further improve waterproofness.

Conventionally, in order to make the cable waterproof,
A method has been adopted in which a waterproof composition that is solid at room temperature and has a softening point or melting point of 60 to 100° C. is filled between cable cores. By the way, in order to fill the above-mentioned waterproof composition, it is necessary to heat the composition to a high temperature above its softening point or melting point. There is a problem in that shrinkage creates voids between the cable core and the metal waterproof tape applied thereon. The void is
Of course, if water enters the cable core, there is a danger that it will become a running channel.

In order to solve the above-mentioned problems, the present invention provides a cable core in which the spaces between a large number of cable wires are filled with a waterproof compound, and a foam tape layer, a metal A watertight cable with a water-blocking tape layer and an organic polymer jacket attached vertically, and a waterproof compound heated and made into a fluid state are filled into the spaces between the many cable wires that make up the cable core. The first step is to apply a foamable tape onto the cable core containing the waterproofing compound, and the second step is to extrude cover the jacket with an organic polymer. It is an object of the present invention to provide a method for manufacturing a watertight cable which further includes a third step of foaming.

Tatsuri The watertight cable of the present invention and the watertight cable manufactured by the method of the present invention have a foamed tape layer between the cable core and the metal waterproof tape layer, so even if the waterproof compound filled in the cable core is Even if the volume shrinks due to cooling after heating and filling, by keeping the foamed tape layer in a compressed state while the cable is in operation, it is possible to create a gap between the cable core and the metal water-shielding tape layer that will serve as a running channel. Generation is prevented.

Further, according to the manufacturing method of the present invention, a foamable tape is applied on the cable core containing the waterproof compound in the second step, and a jacket of the organic polymer is extruded and coated in the third step. By foaming the foamable tape using the heat during extrusion coating, it is possible to easily form a foamed tape layer that is always kept in a compressed state between the cable core and the metal waterproof tape layer.

Figure 1 is an example of a cross-sectional view of a watertight cable manufactured by an embodiment of the specific invention or the method of the invention.

Cable core 2 consisting of multiple cable elements &il 1
A waterproof compound 3 is filled between each of the cable strands 1, and a foamed tape layer 4 is provided on the cable core 2, and a metal water-shielding tape layer 5 is provided on the outer side of the foamed tape layer 4.

An organic polymer jacket 6 is provided on the metal water-shielding tape 6 and is integrally bonded with the metal water-shielding tape 5.

The waterproof compound 3 may be various types of greases that exhibit appropriate fluidity at room temperature and do not require heating during filling operations, such as urea grease or silicone grease, or may have a softening point of 60 to 100°C as described above. Or waterproof compositions that are solid at room temperature and have a melting point, and therefore need to be applied by heating to a high temperature above their softening point or melting point, such as waterproofing compound (#5B) manufactured by Liteco, Inc. in the United States. There may be. In the present invention, since the foamed tape layer 4 has the effect described above, it is particularly suitable for use with the above-mentioned waterproof composition that requires heating during filling.

The foam tape layer 4 is composed of a foam tape made of an organic polymer and having good cushioning properties. For example, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-propylene-diene terpolymer, ethylene-propylene copolymer, acrylonitrile-butadiene-copolymer rubber, styrene-butadiene-copolymer The foamed tape layer 4, which is preferably a foamed tape of elastomer such as rubber, urethane rubber, natural rubber, or butyl rubber, may be formed by horizontally or vertically wrapping the above foamed tape on the cable core 2 in advance. Alternatively, an unfoamed elastomer tape may be applied on the cable core and foamed before, during, or after the application of the metal waterproof tape layer 5 or the organic polymer jacket 6. However, after the watertight cable of the present invention is completed, the foamed tape layer 4 is preferably in a moderately compressed state by the cable core 2 and the metal water-blocking tape layer 5 (or the organic polymer jacket 6). Therefore, the foam tape layer 4 has a thickness of about 0.5 to 1.5 m when it is not compressed, and the foam tape with a foaming degree of about 10 to 70% has a thickness of 95% of the original thickness.
Hereinafter, when forming the foam tape layer 4 using the above-mentioned foamed tape, which is particularly preferably compressed to 90% or less, when applying the metal water-blocking tape N5 or the organic polymer jacket 6. It is preferable to form these layers so as to compress the foam tape layer 4.

Examples of tapes constituting the metal water-shielding tape layer 5 include metal tapes having an adhesive polymer layer on at least one side, such as lead, aluminum, and copper tapes. Furthermore, in the present invention, a composite tape having an adhesive polymer layer on one side and an unfoamed or foamed organic polymer layer capable of forming the foamed tape layer 4 on the other side is used to form the foamed tape layer 4. The metal water-blocking tape layer 5 may also be formed at the same time.

The organic polymer jacket 6 can be formed by conventional extrusion coating of an organic jacketing polymer such as polyethylene or polyvinyl chloride.

Next, examples of the method invention will be described. The first step is
A currently available waterproofing compound, for example a waterproofing compound manufactured by Liteco, Inc. in the United States, may be used for heating and filling in a conventional manner.

FIG. 2 is an example of a cross-sectional view of a foamable tape used in the second step of the present invention, and the foamable tape 7 is composed of an organic polymer layer 71 containing a foaming agent and a reinforcing layer 72. The organic polymer may be, for example, one or a mixture of two or more of the above-mentioned elastomers.The blowing agent is not particularly limited, but the blowing agent may be extrusion coated with the organic polymer jacket in the next third step. A material that exhibits a foaming action due to the heat generated during extrusion coating of the organic polymer is used. As this type of blowing agent, it is preferable to use a volatile liquid such as n-hexane, cyclohexane, □styrene, etc., microencapsulated with a solvent-resistant organic polymer. Examples include Matsumoto Microsphere-F manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.

The amount of blowing agent used is 20 parts by weight per 100 parts by weight of the organic polymer.
Approximately 20 Offili parts are appropriate.

As the reinforcing layer 72, for example, a woven fabric or nonwoven fabric of an organic polymer such as polyester, polypropylene, or nylon is used. Note that if the layer 71 of organic polymer containing a foaming agent has good mechanical strength, reinforcement 1! i
72 is not necessarily necessary.

The foam tape 7 is applied horizontally or vertically on the cable core filled with waterproofing compound, and on top of that, the metal waterproof tape layer 5 is also applied horizontally or vertically.
It is preferably applied vertically.

In the third step, an organic polymer such as polyethylene or polyvinyl chloride is extrusion coated to form an organic polymer jacket, and the foamable tape 7 is foamed by the heat of the organic polymer during extrusion coating.

Although the waterproofing compounds that have been used in the past have the problem of volumetric shrinkage described above, they have a track record of long-term use in terms of deterioration characteristics, electrical properties, and other aspects. According to the present invention, it is possible to easily manufacture a watertight cable that compensates for the drawbacks of conventionally used waterproof compounds and has excellent water running prevention properties.

EXAMPLE 1 The present invention will now be described in more detail with reference to Examples and Comparative Examples.

Electric wire 2 having a polyethylene insulation coating layer with a diameter of 0.9 m
A waterproof compound (#5B manufactured by Liteco, Inc., USA), which had been heated to 105° C. and made fluid, was filled in the gap between the cable cores consisting of 00 pairs by a conventional method. Then,
After cooling the cable core to approximately room temperature, butyl rubber 1
00 parts by weight of a foaming agent (microencapsulated foaming agent manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.: Matsumoto Microsphere-F was used). A foam tape (tape width 75mm) with a 140μ thick polyester nonwoven fabric reinforcing layer pasted on is attached vertically, and on top of that, a 50μ thick modified ethylene-acetic acid layer is placed on one side of the 200μ thick aluminum. An aluminum tape laminated with a vinyl copolymer is laminated vertically with the ethylene-vinyl acetate copolymer layer on the outside, and polyethylene is extruded on top of it at 200°C to form a polyethylene jacket. Foamed.

[Brief explanation of the drawing]

FIG. 1 is an example of a cross-sectional view of a watertight cable manufactured by a specific embodiment of the present invention or the method of the present invention. L...Cable wire 2...Cable core 3...Waterproof compound 4...Foamed tape layer 5...Metal water-shielding tape layer 6...Organic polymer jacket FIG. It is an example of a cross-sectional view of the foamable tape used. 7. Foaming tape 71, organic polymer layer 72 containing foaming agent, reinforcing layer

Claims (1)

[Claims] 1. A foam tape layer is sequentially formed on a cable core in which the spaces between a large number of cable wires are filled with a waterproof compound;
A watertight cable characterized by having a metal water-shielding tape layer and an organic polymer jacket. 2. The watertight cable according to claim 1, wherein the foam tape layer is held in a compressed state by the cable core and a metal water-shielding tape layer or an organic polymer jacket layer. 3. The first step is to fill the spaces between the many cable wires that make up the cable core with a waterproof compound that has been heated and made into a fluid state.The second step is to apply foam tape on top of the cable core containing the waterproof compound. and a third step of extrusion coating an organic polymer jacket and foaming the above foamable tape using the heat generated during extrusion coating of the organic polymer. 4. The method for producing a watertight cable according to claim 3, wherein the foamable tape is a tape made of an organic polymer containing microcapsules containing a volatile organic liquid as a foaming agent. 5. After the foam tape is applied on the cable core, a metal water-blocking tape having an adhesive polymer layer on at least one side is further applied vertically thereon, according to any one of claims 3 to 4. A method for manufacturing a watertight cable as described in .