FEP (fluorinated-ethylene-propylene)

FEP, like PFA is melt processible so can be extruded and injection moulded as well as transfer moulded. It is transparent which is why it is used as a shatterproof coating on fluorescent lamps. Like all fully fluorinated polymers, FEP has very good chemical and UV resistance, low friction coefficient,  and can withstand high temperatures though not as high as PFA or PTFE. Flex-crack resistance is not as good as PFA but can be significantly improved, (by a factor of 10) by using a third monomer – usually a PFAVE, (per-fluorinated-alkyl-vinyl-ether). Such modified FEP’s are therefore ter-polymers.  FEP has very good electrical insulation properties with dielectric constant similar to PFA and PTFE though dielectric strength is not quite as high as PFA.

FEP can replace PFA to line pipes, vessels, valves, fittings and heat exchangers if the temperature resistance requirements are less extreme. It is also used to make tubing, sleeving, electric cable coating, and injection moulded parts.