Abstract: A novel adhesion adjusting additive for semiconductive dielectric shields for electric power cables is disclosed. The additive comprises a compound with a carbon-oxygen dipole, and a molecular weight less than 20,000 daltons. The additive is blended with a base polymer and conductive carbon black to form the material for the semiconductive shield.

Abstract: A composition of matter for use as dielectric shield in an electric power cable having insulation of XLPE, EPR or EPDM comprises: a base polymer which is a copolymer of ethylene with a mono-unsaturated ester; conductive carbon black in an amount to give the composition an electrical resistivity below 500 Am; and as an adhesion-adjusting additive, 1-20% by weight of the base polymer of a copolymer which consists essentially of ethylene and a comonomer having in its molecule at least one carbon-oxygen dipole, said copolymer having a molecular weight less than 20,000 Daltons but a melting point higher than 30° C. This new class of additive permits use of EVA's with lower vinyl acetate content than prior art additives and so enables the composition to have less rubbery physical properties.

Abstract: A composition of matter useful for strippable shields for electric power cables comprises:a base polymer which is a copolymer of ethylene with a mono-unsaturated ester;conductive carbon black in an amount to give the composition an electrical resistivity below 500 .OMEGA.m; andas adhesion-controlling additive, a copolymer of ethylene with a mono-unsaturated ester containing from 0.5 to 2% by weight of side-chains each of which comprises an inflexible ring structure bonded to a backbone carbon atom of the copolymer with at most five atoms interposed between them.The compositions have the advantage of being less rubbery than current strippable-screen compositions and can be made successfully with copolymers of lower ester content.