| 摘要 |
Electrical conductors which are insulated by an inner polymeric layer having little or no cross-linking and high elongation, and an outer polymeric layer having a relatively high level of cross-linking and low elongation. Preferably each of the components of polymeric compositions employed for producing the inner and outer polymer layers comprises a crystalline fluorocarbon polymer, especially an ethylene/tetrafluoroethylene copolymer. Such articles can be prepared by (1) melt-extruding a first polymeric composition which contains little or no crosslinking agent, and a second polymer composition which contains a greater amount of cross-linking agent, (2) maintaining the two extrudates under conditions such that cross-linking agent migrates from the second to the first composition, and (3) cross-linking both compositions, preferably by radiation. |
