Anaconda-ericsson Inc.

George N Benjamin

Robert M Wade

Daniel H Jessop

Marwick H Solomon

An improved multilayer electric cable is disclosed having a conductive core, an extruded strand shield (ESS) layer, an insulating layer of polymeric insulation material surrounding the core and coaxial therewith, a semiconductive insulation shield (EIS) layer strippably bonded to the insulation layer surrounding it and coaxial therewith and, preferably, a plurality of axially extending drain wires disposed within the semiconductive EIS layer. The semiconductive EIS layer is formed of a copolymer of an ethylene/acrylate/monoalkyl ester of 1,4-butenedioic acid copolymer, conductive carbon black, a peroxide curing agent and polyethylene or polyethylene copolymer. The semiconductive EIS layer is applied by extrusion at elevated temperature in a dry gas atmosphere. Such dry processing conditions are sufficiently severe that the copolymer of ethylene/acrylate/ester can reliably serve as a suitable basis for the semiconductive EIS layer, since other conventional semiconductive compositions are susceptible to being adversely affected by the severe conditions of dry processing.

Process for continuous production of a multilayer electric cable

An improved multilayer electric cable is disclosed having a conductive core, an extruded strand shield (ESS) layer, an insulating layer of polymeric insulation material surrounding the core and coaxial therewith, a semi-conductive insulation shield (EIS) layer strippably bonded to the insulation layer surrounding it and coaxial therewith and, preferably, a plurality of axially extending drain wires disposed within the semiconductive EIS layer. The semi-conductive EIS layer is formed of a copolymer of an ethylene/alkylacrylate/monoalkyl ester of 1,4-butenedioic acid copolymer, conductive carbon black, and a peroxide curing agent and preferably also a copolymer of ethylene and propylene or a copolymer of ethylene, propylene and an unconjugated diene. The semi-conductive EIS layer is applied by extrusion at elevated temperature in a dry gas atmosphere. Such dry processing conditions are sufficiently severe that the copolymer of ethylene/acrylate/ester can reliably serve as a suitable basis for the semi-conductive EIS layer, since other conventional semi-conductive compositions are susceptible to being adversely affected by the severe conditions of dry processing.

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Stamford, CT, United States of America

George N Benjamin