Self-sealing electrical cable using rubber resins
View Patent ↗An electrical cable and a method for manufacturing the electrical cable are provided in which a plurality of insulated conductors have an inner protective layer extruded thereabout. A plurality of longitudinally extending ribs or fins or exterior ribbed or finned surfaces are formed outward of the inner protective layer between which exist a plurality of voids. An outer insulation layer can be formed in the same operation as the fins or ribbed surface and the inner layer or in a subsequent operation. A self-sealing elastomeric material is applied to the conductor surface or is present between the fins and between the inner protective layer and the outer insulation layer.
1. A method of making a self-sealing electrical cable, the method comprising:
(a) providing a stranded conductor;
(b) forming a multi-layer flow comprising:
an inner layer,
an outer layer,
a plurality of fins connecting the inner layer and the outer layer, and
a sealant material disposed between the inner layer, the outer layer, and the plurality of fins; and
(c) applying the multi-layer flow onto the stranded conductor;
wherein the multi-layer flow is formed prior to being applied onto the stranded conductor, and the composition of the inner layer and the outer layer are different.
2. The method of claim 1 , wherein the stranded conductor comprises copper, aluminum, copper alloys, or aluminum alloys.
3. The method of claim 1 , wherein the self-sealing electrical cable is a 600 volt cable.
4. The method of claim 1 , wherein the inner layer comprises a thermoplastic or a thermoset.
5. The method of claim 1 , wherein the inner layer comprises a polyethylene or a PVC.
6. The method of claim 1 , wherein the outer layer comprises a thermoplastic or a thermoset.
7. The method of claim 1 , wherein the outer layer comprises a polyethylene or a PVC.
8. The method of claim 1 , wherein the sealant material comprises an elastomer material.
9. The method of claim 8 , wherein the elastomer material is a dielectric.
10. The method of claim 8 , wherein the elastomer material does not absorb moisture or swell upon contact with moisture.
11. The method of claim 8 , wherein the elastomer material has a 100 gram needle penetration value greater than 100 tenths of a millimeter at 25° C.
12. The method of claim 8 , wherein the elastomer material is a butyl rubber.
13. The method of claim 1 , wherein the sealant material comprises a flow modifier.
14. The method of claim 13 , wherein the sealant material comprises from about 25% to about 60% flow modifiers.
15. The method of claim 13 , wherein the flow modifier comprises a polyisobutene, isobutene, or a combination thereof.
16. The method of claim 1 , wherein the sealant material comprises a filler.
17. The method of claim 16 , wherein the filler comprises glass or ceramic microspheres.
18. The method of claim 1 , wherein the sealant material comprises a polyisobutene.
19. The method of claim 1 , wherein the sealant material comprises a butyl rubber, a styrene butadiene rubber, an ethylene propylene diene monomer rubber, a natural rubber, a polyolefin elastomer, or a combination thereof.
20. The method of claim 1 , wherein the sealant material comprises a butyl rubber.
21. The method of claim 1 , wherein the sealant material is flowable at about −20° C.
22. The method of claim 1 , wherein the self-sealing electrical cable has, per 50 feet of cable, initially less than about 0.2 inch shrinkback of the inner layer and the outer layer after performing a complete circular cut of the inner layer and the outer layer.
23. The method of claim 1 , wherein the self-sealing electrical cable has, per 50 feet of cable, less than about 0.5 inch shrinkback of the inner layer and the outer layer subsequent to accomplishing a complete circular cut of the inner layer and the outer layer and aging for one week.
24. The method of claim 1 , wherein the multi-layer flow is formed within a multi-layer extrusion head prior to be applied onto the stranded conductor.
25. The method of claim 1 , wherein the self-sealing electrical cable comprises at least 2 fins.
26. The method of claim 1 , wherein the self-sealing electrical cable comprises 6 fins.
27. The method of claim 1 , wherein the fins comprise a portion of the inner layer and a portion of the outer layer.
28. A method of making a self-sealing electrical cable, the method comprising:
(a) providing a conductor comprising copper, aluminum, copper alloys, or aluminum alloys;
(b) forming a multi-layer flow comprising:
an inner layer comprising a thermoplastic or a thermoset,
an outer layer comprising a thermoplastic or a thermoset,
a plurality of fins connecting the inner layer and the outer layer, and
a sealant material disposed between the inner layer, the outer layer, and the plurality of fins; and
(c) applying the multi-layer flow onto the conductor;
wherein the multi-layer flow is formed prior to being applied onto the conductor, and the composition of the inner layer and the outer layer are different.
29. The method of claim 28 , wherein the sealant material comprises a polyisobutene.
30. The method of claim 28 , wherein the sealant material comprises a butyl rubber, a styrene butadiene rubber, an ethylene propylene diene monomer rubber, a natural rubber, a polyolefin elastomer, or a combination thereof.
31. The method of claim 28 , wherein the fins comprise a portion of the inner layer and a portion of the outer layer.