Coaxial cable with improved properties and process of making same
First Claim
1. An electrical cable having at least one inner conductor, an outer tubular conductor circumferentially surrounding the inner conductor and a gas expanded polyolefin dielectric formed by a composite of polyolefin, entrapped gas, and particles of a nucleating agent disposed between the inner and outer conductors to electrically insulate the inner and outer conductors from each other, the improvement comprising said composite of polyolefin, and entrapped gas and nucleating agent having a density between 0.20 and 0.10 grams per cubic centimeter and said nucleating agent being composed of undecomposed particles selected from the group consisting essentially of azobisformanies, calcium carbonate, silica, and silicates.
1 Assignment
0 Petitions
Accused Products
Abstract
Disclosed is a coaxial cable having greatly improved mechanical and electrical properties derived from a foamed dielectric having a dielectric constant in the range of 1.32 to 1.1, a density between 0.1 and 0.29 grams per cubic centimeter, said foamed dielectric having dispersed throughout it undecomposed particles of a nucleating agent such cable being provided by a novel method of coating a center conductor of the cable with a dielectric with an extruded cellular polyolefin base composition which has been rendered cellular by the direct injection of a blowing agent in a liquid form into the polymer during an extrusion process.
62 Citations
25 Claims
- 1. An electrical cable having at least one inner conductor, an outer tubular conductor circumferentially surrounding the inner conductor and a gas expanded polyolefin dielectric formed by a composite of polyolefin, entrapped gas, and particles of a nucleating agent disposed between the inner and outer conductors to electrically insulate the inner and outer conductors from each other, the improvement comprising said composite of polyolefin, and entrapped gas and nucleating agent having a density between 0.20 and 0.10 grams per cubic centimeter and said nucleating agent being composed of undecomposed particles selected from the group consisting essentially of azobisformanies, calcium carbonate, silica, and silicates.
- 8. An electrical cable having at least one inner conductor, an outer tubular conductor circumferentially surrounding the inner conductor and a gas expanded polyolefin dielectric formed by a composite of polyolefin, entrapped gas, and particles of a nucleating agent disposed between the inner and outer conductors to electrically insulate the inner and outer conductors from each other, the improvement comprising said composite of polyolefin, entrapped gas nucleating agent having a density between 0.29 and 0.10 grams per cubic centimeter and being essentially free of decomposition residues of said nucleating agent.
- 15. An electrical cable having at least one inner conductor, an outer tubular conductor circumferentially surrounding the inner conductor and a gas expanded polyolefin dielectric formed by a composite of polyolefin, entrapped gas, and particles of a nucleating agent disposed between the inner and outer conductors to electrically insulate the inner and outer conductors from each other, the improvement comprising said composite having a density between 0.29 and 0.10 grams per cubic centimeter a dielectric constant no greater than 1.32 and said nucleating agent being composed of undecomposed particles selected from the group consisting essentially of azobisformanies, calcium carbonate, silica, and silicates.
- 17. An electrical cable having at least one inner conductor, an outer tubular conductor circumferentially surrounding the inner conductor and a gas expanded polyolefin dielectric formed by a composite of polyolefin, entrapped gas, and particles of a nucleating agent disposed between the inner and outer conductors to electrically insulate the inner and outer conductors from each other, the improvement comprising said composite having a dielectric constant of no greater than 1.32 and a density between 0.29 and 0.10 grams per cubic centimeter and being essentially free of decomposition residues of said necleating agent.
- 20. An electrical cable having at least one inner conductor, an outer tubular conductor circumferentially surrounding said inner conductor and a gas expanded polyolefin dielectric formed by a composite of polyolefin, entrapped gas, and a nucleating agent disposed between the inner and outer conductors to electrically insulate the inner and outer conductors from each other, the improvement comprising the said composite having a dielectric constant of not more than 1.32 and not less than 0.10 and being essentially free of decomposition residues of said nucleating agent.
Specification