Strippable cable shield compositions
AssigneeGeneral Cable Technologies Corporation
InventorMark R. Easter
Life of this patent
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Abstract
A semiconductive resin composition for use as a semiconductive layer in contact with a crosslinked wire and cable insulation layer is disclosed for use where the insulation layer is crosslinked using a peroxide cure system. The resin has a two component base polymer where the first component has a weight average molecular weight of not more than 200,000. The second component is either a polymer having a melting point between 110° C. and 130° C. or a nitrile rubber. The composition also has an adhesion modifying compound different from the base polymer and carbon black. Methods of making the composition and cables using the composition are also disclosed.
Claims50
A semiconductive resin composition for use as a semiconductive layer in contact with a crosslinked wire and cable insulation layer, wherein said insulation layer is crosslinked using a peroxide cure system, said resin composition comprising,
- 15 to 85 weight percent, based upon the weight of the semiconductive resin composition, of a base polymer comprising at least two components, a first component having a weight average molecular weight of not more than 200,000 and selected from the group consisting of ethylene vinyl acetate copolymers, ethylene alkyl acrylate copolymers wherein the alkyl group is selected from C1 to C6 hydrocarbons, ethylene alkyl methacrylate copolymers wherein the alkyl group is selected from C1 to C6 hydrocarbons and ethylene alkyl acrylate alkyl methacrylate terpolymers wherein the alkyl group is independently selected from C1 to C6 hydrocarbons;
- a second component selected from the group consisting of polymers having a melting point between 110° C. and 130° C. and nitrile rubbers , wherein said second component is from about 1 to 40 weight percent of the base polymer, and
- 0.1 to 20 weight percent, based upon the weight of the semiconductive resin composition, of a an adhesion modifying compound different from said base polymer comprising a hydrocarbon wax or ethylene vinyl acetate wax;
- and
- 15 to 45 weight percent, based upon the weight of the semiconductive resin composition, of a conductive carbon black in an amount sufficient to give the semiconductive resin composition a resistance below about 550 ohm-meter;
- wherein said semiconductive resin composition forms a strippable semiconductive layer in contact with said peroxide crosslinked insulation layer.
A method of making a semiconductive resin composition in contact with a crosslinked wire and cable insulation layer, wherein said insulation layer is crosslinked using a peroxide cure system, comprising the steps of:
- (a) compounding 15 to 85 weight percent, based upon the weight of the semiconductive resin composition, of a base polymer comprising at least two components, a first component having a weight average molecular weight of not more than 200,000 and selected from the group consisting of ethylene vinyl acetate copolymers, ethylene alkyl acrylate copolymers wherein the alkyl group is selected from C1 to C6 hydrocarbons, ethylene alkyl methacrylate copolymers wherein the alkyl group is selected from C1 to C6 hydrocarbons and ethylene alkyl acrylate alkyl methacrylate terpolymers wherein the alkyl group is independently selected from C1 to C6 hydrocarbons;
- a second component selected from the group consisting of polymers having a melting point between 110° C. and 130° C. and nitrile rubbers , wherein said second component is from about 1 to 40 weight percent of the base polymer, with;
- 0.1 to 20 weight percent, based upon the weight of the semiconductive resin composition, of a an adhesion modifying compound different from said base polymer comprising a hydrocarbon wax or ethylene vinyl acetate wax;
- and
- a conductive carbon black in an amount sufficient to give the semiconductive shield a resistance below about 550 ohm-meter together in a mixer to form a mixture,
- (b) extruding the mixture to form the semiconductive resin composition, wherein said semiconductive resin composition forms a strippable semiconductive layer in contact with said peroxide crosslinked wire and cable insulation layer.
A medium voltage electric power cable comprising a conductive core, an insulation layer crosslinked using a peroxide cure system, a strippable semi-conductive shield formed from a semiconductive resin composition, a grounded metal wire or tape and a jacket;
- wherein said semiconductive resin composition comprises,
- 15 to 85 weight percent, based upon the weight of the semiconductive resin composition, of a base polymer comprising at least two components, a first component having a weight average molecular weight of not more than 200,000 and selected from the group consisting of ethylene vinyl acetate copolymers, ethylene alkyl acrylate copolymers wherein the alkyl group is selected from C1 to C6 hydrocarbons, ethylene alkyl methacrylate copolymers wherein the alkyl group is selected from C1 to C6 hydrocarbons and ethylene alkyl acrylate alkyl methacrylate terpolymers wherein the alkyl group is independently selected from C1 to C6 hydrocarbons;
- a second component selected from the group consisting of polymers having a melting point between 110° C. and 130° C. and nitrile rubbers , wherein said second component is from about 1 to 40 weight percent of the base polymer, and
- 0.1 to 20 weight percent, based upon the weight of the semiconductive resin composition, of a an adhesion modifying compound different from said base polymer comprising a hydrocarbon wax or ethylene vinyl acetate wax;
- and
- 15 to 45 weight percent, based upon the weight of the semiconductive resin composition, of a conductive carbon black in an amount sufficient to give the semiconductive resin composition a resistance below about 550 ohm-meter.
Dependencies are inferred from the claim text.