JPS62272410A - 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] 3. Detailed explanation of the invention! Yo Yuuki Riko! The present invention relates to a novel watertight cable with excellent anti-water running properties.

Conventional technology and problems to be solved When making a cable waterproof, the gaps between the many cable cores within the sheath are generally filled with a waterproof compound.
When this type of cable is directly buried underground, it is required to improve its water-retaining properties.

Conventionally, in order to make the cable waterproof,
A method has been adopted in which a waterproof compound, which is solid at room temperature and has a softening point or melting point of 60 to 100° C., is filled between the cable cores. By the way, in order to fill the above-mentioned waterproof compound, it is necessary to apply the composition by heating it to a high temperature above its softening point or melting point, but cooling after application causes the composition to shrink in volume. However, there is a problem in that a gap is created between the cable core and the metal waterproof tape applied thereon. Of course, there is a risk that the gap will become a running channel if water enters the cable core.

In order to solve the above problems, the present invention provides a cable core filled with a waterproof compound that is solid at room temperature and has a softening point or melting point of 60-100°C between the cable strands. In a structure having a metal water-shielding tape layer and an organic polymer jacket on the cable core, a water-absorbing organic polymer string is spirally wound on the cable core or on the metal water-shielding tape layer. The aim is to provide a watertight cable with the following characteristics.

■ In the present invention, since the spiral winding of the water-absorbing organic polymer edge is present on the cable core (that is, between the cable core and the metal water-shielding tape layer) or on the metal water-shielding tape layer, Even if water intrudes into one cable, water is captured by the water absorption by the spiral wound body of one of the water-absorbing organic polymer edges mentioned above and its own swelling action, and water is prevented from propagating into the cable. .

Figures 1 to 4 are perspective views of cables according to embodiments of the present invention, in which 1 is a cable core made up of a large number of cable strands, and 2 is a section between each of the above-mentioned cable strands. A waterproofing compound that is solid at room temperature and has a softening point or melting point of 60 to 100°C is filled in, 3 is a cable core l restraining tape, 4 is a spirally wound water-absorbing organic polymer edge, 5 is a longitudinally attached The metal waterproof tape layer 6 is an organic polymer jacket.

In the embodiment of FIGS. 1 and 2, the water-absorbing organic polymer rim 4 is applied over the cable core l (i.e. between the cable core and the metal waterproof tape layer 5), while In the embodiments of FIGS. 3 and 4, the water-absorbing organic polymer border 4 is applied on top of the metal waterproof tape layer 5. In the embodiment of FIGS. Furthermore, in the embodiments shown in FIGS. 1 and 3, the water-absorbing organic polymer edge 4 is spirally wound only in one direction, but in the embodiments shown in FIGS. teeth,
On top of the water-absorbing 11r polymer string 4 spirally wound in one direction, one more water-absorbing organic polymer edge 4° is wound overlappingly in the opposite direction.

As the waterproof compound 2, for example, a waterproof compound (95B) manufactured by Liteco, Inc. in the United States is used.

The waterproof compound 2 may be heated and filled using a conventional method.

Examples of water-absorbing organic polymers as constituent materials for the string 4 include polyacrylates, carboxymethylcelluloses, polyvinyl alcohols, polyethylene oxides, vinyl acetate-acrylic acid graft copolymers, and starch-polyacrylonitrile grafts. copolymers, isobutylene-maleic acid copolymers, etc.

The string 4 may be a thread-like material made by twisting together single fibers of a water-absorbing organic polymer as described above, a string-like material made by twisting a large number of such thread-like materials, or a film made of a water-absorbing organic polymer. A water-absorbing organic polymer that can be made by processing a net into a string shape, or even by processing the above-mentioned polymer onto a base material such as a woven fabric or non-woven fabric into a string shape! kl)
Although it is preferable that the spiral winding pitch of No. 4 be as small as possible, even a pitch approximately equal to the outer diameter of the metal water-blocking tape layer 5 is sufficiently effective. In the event that water gets into the cable, the water-absorbing organic polymer edge 4
As mentioned above, as shown in the embodiments of FIGS. 2 and 4, the water-absorbing organic polymer rim formed by spirally winding in one direction If one more layer of water-absorbing organic polymer edge 4 is wrapped on top of 4 in the opposite direction, even if water that has entered the cable tries to move in the longitudinal direction of the cable, the string will 4 or the string 4°, water is captured more reliably during this traversal by the above-mentioned water absorption or swelling effect.

Therefore, in the present invention, it is particularly preferable to alternately wind the left and right windings as in the embodiment shown in FIG. 2 or 4.

The metal water-shielding tape is preferably a tape made of metal such as lead, aluminum, copper, etc., which has one layer of adhesive polymer on at least one side. It is preferable to have good adhesion to 6.

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

In the present invention, the restraining piece 13 on the cable core l is not necessarily required, but if it is adopted, it will be easier to spirally wind the machine polymer string 4 and vertically attach the metal water-blocking tape. If a tape having a grease layer on one or both sides of the tape (hereinafter referred to as grease tape) as described later is used as the restraining tape 3, the water-shielding effect of the cable will be further improved.

Grease generally has fluidity at room temperature, and at 100℃
It has the property of not easily flowing down even when heated to high temperatures. Therefore, even if volume shrinkage occurs due to cooling of the waterproof compound used in the present invention, the voids that would otherwise occur on the cable core are filled by the grease due to the fluidity of the grease layer of the grease tape applied on the cable core. Generation of voids is prevented. Further, as described above, grease has a property that it does not easily flow down even when heated to a high temperature, so even if the cable encounters high temperatures, there is no problem of grease flowing down.

Grease tapes include polyester, nylon or other polymeric woven or non-woven tapes, lead,
A tape having a layer of grease described below on one or both sides of the tape, such as metal water-shielding tape made of copper, aluminum, etc., is used. When the thickness of the grease layer is applied to both sides of the tape, the total thickness of both sides is preferably about 0.2 to 3.0 mm, particularly about 0.3 to 1.01 mm.

Examples of grease include petroleum oils such as transformer oil, spindle oil, cable oil, insulation oil, machine oil, natural oils such as rosin oil, castor oil, olive oil, whale oil, polybutene, and chlorinated oils. base oils such as paraffin, polyethylene glycol, synthetic polymers, and fatty acids such as sodium, potassium, lithium, barium,
Calcium, strontium, zinc, lead, cadmium,
Metal soap thickeners that are salts with aluminum etc., bentonite, silica gel, copper phthalocyanine, urea,
Grease prepared by appropriately combining a thickener such as a non-soap thickener such as polymer powder, petroleum hydrocarbon oil, olefin polymer oil such as polybutene, polyalkylene glycol oil, Examples include halogenated hydrocarbon oil such as chlorinated paraffin, liquid rubber such as liquid chloroprene rubber, and a mixture of a polymer compound such as silicone oil and the above grease. Specific examples of grease include sodium stone kengris, lithium stone kengris, potassium stone kengris, calcium stone kengris, aluminum stone kengris, composite calcium stone kengris, composite aluminum stone kengris, urea grease,
Examples include silicone grease, bentonite grease, Teflon grease, and copper phthalocyanine grease.

Among the above greases, JIS K 22205.3
Those having a working consistency of 85 to 475 at 25°C, furthermore, those having a working consistency of 100 to 400.
Particularly preferred are those having a molecular weight of 150 to 350. Particularly preferred are those having the above-mentioned mixing consistency and excellent electrical insulation properties, such as urea grease and silicone grease.

Grease tape may be applied on the cable core while the waterproof compound filled in the cable core is still at a high temperature, but immediately after the above filling process is completed, the cable core should be exposed to air cooling, etc. It is preferable that the waterproofing compound in the cable core undergoes considerable to sufficient volumetric contraction by cooling in a conventional manner before application. Although it may be applied on the cable core l, it is preferable to increase the aperture when applying the tape vertically so that the depressions and gaps created in the cable core due to the volume contraction of the waterproof compound are sufficiently filled with grease.

Although the conventionally used waterproofing compounds have the above-mentioned volumetric shrinkage problem, they have a long history of use in terms of deterioration characteristics, electrical properties, and other aspects. A watertight cable with excellent water running prevention properties can be easily produced by compensating for the defects of the compound.

[Brief explanation of the drawing]

1 to 4 are perspective views of cables according to embodiments of the present invention, in which 1 is a cable core made up of a large number of cable strands, and 2 is a cable core filled between each of the above-mentioned cable strands. A waterproof compound that is solid at room temperature and has a softening point or melting point of 60 to 100 degrees Celsius; 3 is a restraining tape for the cable core 1; 4 is a spirally wound water-absorbing organic polymer string; 5 is a longitudinally attached metal shield. The water tape layer 6 is an organic polymer jacket.

Claims (1)

[Claims] 1. On the cable core filled with a waterproof compound that is solid at room temperature and has a softening point or melting point of 60 to 100°C between the cable strands, a metal waterproof tape layer and an organic polymer layer are formed. 1. A watertight cable having a jacketed structure, comprising a water-absorbing organic polymer string spirally wound on the cable core or on the metal water-blocking tape layer. 2. The watertight cable according to claim 1, wherein a water-absorbing organic polymer string is further wound over the water-absorbing organic polymer string spirally wound in one direction, and further wound in an opposite direction. .