Wikipedia
ECTFE
ECTFE (Ethylene ChloroTriFluoroEthylene) was designed to provide excellent chemical resistance in heavy duty corrosion applications. It is a partially fluorinated polymer (a fluoropolymer), semi-crystalline and can be processed in the melt. Chemically it is a copolymer of ethylene and chlorotrifluoroethylene. It is marketed under the brand name Halar ECTFE by Solvay Specialty Polymers, a subsidiary of Solvay.