Raychem Limited

Other

Donald A Reed

Hans E Lunk

Andrew N Au

Marguerite E Deep

Charles Hill

Melt-shapeable polymeric compositions comprising a first fluoropolymer of relatively low crystallinity, e.g. a copolymer of tetrafluoroethylene and a perfluorinated comonomer, and a second fluoropolymer of relatively high crystallinity, especially a fluoropolymer obtained by irradiating PTFE or another fluoropolymer which cannot be melt-shaped in the absence of other polymers. The weight ratio of the first to the second polymer is preferably 0.3:1 to 2.5:1. The compositions have a wide variety of uses, for example as insulating materials or, if they contain carbon black or another conductive filler, as PTC conductive polymers.

Melt-shapeable fluoropolymer compositions

Foamed polymers having low loss at microwave frequencies are prepared through use of perfluorinated alkane foaming agents. The invention is particularly valuable for polymers which are melt-processed at high temperatures, especially fluoropolymers such as tetrafluoroethylene copolymers. The polymeric foams are particularly useful as electrical insulation, especially for coaxial cables suitable for use at microwave frequencies.

Growing community of inventors

Menlo Park, CA, United States of America

Donald A Reed