Patent ID: 8404756

Claim:
Process for forming insulation onto a conductor comprising: forming a composition by blending together a first copolymer comprising tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkyl vinyl ether) and a second copolymer consisting essentially of tetrafluoroethylene and perfluoro(alkyl vinyl ether), wherein the alkyl contains 1-4 carbon atoms, with foam cell nucleating agent and a blowing agent; melt draw down extruding the composition from an extrusion die onto the conductor to form the insulation on the conductor, the melt down extruding forming a cone of the composition in a molten state extending from the die to the formation of the insulation on the conductor, wherein the melting temperature of the second copolymer is no more than 35° C. greater than the melting temperature of the first copolymer, and/or wherein the first copolymer and the second copolymer each have a melt flow rate (MFR) within the range of 1 to 40 g/10 min and the MFR of one of the first and second copolymers is at least twice that of the other copolymer, the blowing agent causing the molten composition to foam on the conductor.