MELT-SHAPABLE FLUOROPOLYMER COMPOSITIONS

摘要

Melt-shapeable polymeric compositions comprising a first fluoropolymer of relatively low crystallinity and a second fluoropolymer of relatively high crystallinity, especially a fluoropolymer obtained by irradiating a fluoropolymer which cannot be melt-shaped in the absence of other polymers. The first fluoropolymer is preferably a copolymer of tetrafluoroethylene and an perfluorinated comonomer, e.g. hexafluoropropylene or a perfluorinated vinyl ether. The second fluoropolymer is preferably tetrafluoroethylene which has been irradiated to a dosage of 2.5 to 40 Mrad. The weight ratio of the first to the second polymer is preferably 0.3:1 to 2.5:1. The compositions are melt-shapeable, and the resulting shaped products have a valuable combination of properties derived from both fluoropolymers. For example, the compositions are particularly useful for electrical insulation, especially as low loss foamed insulation in coaxial cables.